Since the implementation of PEP 393 in Python 3.3, Unicode objects internally use a variety of representations, in order to allow handling the complete range of Unicode characters while staying memory efficient. There are special cases for strings where all code points are below 128, 256, or 65536; otherwise, code points must be below 1114112 (which is the full Unicode range).
Py_UNICODE* and UTF-8 representations are created on demand and cached
in the Unicode object. The Py_UNICODE* representation is deprecated
and inefficient; it should be avoided in performance- or memory-sensitive
situations.
Due to the transition between the old APIs and the new APIs, Unicode objects can internally be in two states depending on how they were created:
PyUnicode_FromUnicode()) and only bear the Py_UNICODE* representation; you will have to call PyUnicode_READY() on them before calling any other API.Note
The “legacy” Unicode object will be removed in Python 3.12 with deprecated APIs. All Unicode objects will be “canonical” since then. See PEP 623 for more information.
These are the basic Unicode object types used for the Unicode implementation in Python:
Py_UCS4Py_UCS2Py_UCS1These types are typedefs for unsigned integer types wide enough to contain
characters of 32 bits, 16 bits and 8 bits, respectively. When dealing with
single Unicode characters, use Py_UCS4.
New in version 3.3.
Py_UNICODEThis is a typedef of wchar_t, which is a 16-bit type or 32-bit type
depending on the platform.
Changed in version 3.3: In previous versions, this was a 16-bit type or a 32-bit type depending on whether you selected a “narrow” or “wide” Unicode version of Python at build time.
PyASCIIObjectPyCompactUnicodeObjectPyUnicodeObjectThese subtypes of PyObject represent a Python Unicode object. In
almost all cases, they shouldn’t be used directly, since all API functions
that deal with Unicode objects take and return PyObject pointers.
New in version 3.3.
PyUnicode_TypePyTypeObject represents the Python Unicode type. It is exposed to Python code as str.The following APIs are really C macros and can be used to do fast checks and to access internal read-only data of Unicode objects:
PyUnicode_Check(PyObject *o)PyUnicode_CheckExact(PyObject *o)PyUnicode_READY(PyObject *o)Ensure the string object o is in the “canonical” representation. This is required before using any of the access macros described below.
Returns 0 on success and -1 with an exception set on failure, which in
particular happens if memory allocation fails.
New in version 3.3.
Deprecated since version 3.10, will be removed in version 3.12: This API will be removed with PyUnicode_FromUnicode().
PyUnicode_GET_LENGTH(PyObject *o)Return the length of the Unicode string, in code points. o has to be a Unicode object in the “canonical” representation (not checked).
New in version 3.3.
PyUnicode_1BYTE_DATA(PyObject *o)PyUnicode_2BYTE_DATA(PyObject *o)PyUnicode_4BYTE_DATA(PyObject *o)Return a pointer to the canonical representation cast to UCS1, UCS2 or UCS4
integer types for direct character access. No checks are performed if the
canonical representation has the correct character size; use
PyUnicode_KIND() to select the right macro. Make sure
PyUnicode_READY() has been called before accessing this.
New in version 3.3.
PyUnicode_WCHAR_KINDPyUnicode_1BYTE_KINDPyUnicode_2BYTE_KINDPyUnicode_4BYTE_KINDReturn values of the PyUnicode_KIND() macro.
New in version 3.3.
Deprecated since version 3.10, will be removed in version 3.12: PyUnicode_WCHAR_KIND is deprecated.
PyUnicode_KIND(PyObject *o)Return one of the PyUnicode kind constants (see above) that indicate how many bytes per character this Unicode object uses to store its data. o has to be a Unicode object in the “canonical” representation (not checked).
New in version 3.3.
PyUnicode_DATA(PyObject *o)Return a void pointer to the raw Unicode buffer. o has to be a Unicode object in the “canonical” representation (not checked).
New in version 3.3.
PyUnicode_WRITE(int kind, void *data, Py_ssize_t index, Py_UCS4 value)Write into a canonical representation data (as obtained with
PyUnicode_DATA()). This macro does not do any sanity checks and is
intended for usage in loops. The caller should cache the kind value and
data pointer as obtained from other macro calls. index is the index in
the string (starts at 0) and value is the new code point value which should
be written to that location.
New in version 3.3.
PyUnicode_READ(int kind, void *data, Py_ssize_t index)Read a code point from a canonical representation data (as obtained with
PyUnicode_DATA()). No checks or ready calls are performed.
New in version 3.3.
PyUnicode_READ_CHAR(PyObject *o, Py_ssize_t index)Read a character from a Unicode object o, which must be in the “canonical”
representation. This is less efficient than PyUnicode_READ() if you
do multiple consecutive reads.
New in version 3.3.
PyUnicode_MAX_CHAR_VALUE(o)Return the maximum code point that is suitable for creating another string based on o, which must be in the “canonical” representation. This is always an approximation but more efficient than iterating over the string.
New in version 3.3.
PyUnicode_ClearFreeList()PyUnicode_GET_SIZE(PyObject *o)Return the size of the deprecated Py_UNICODE representation, in
code units (this includes surrogate pairs as 2 units). o has to be a
Unicode object (not checked).
Deprecated since version 3.3, will be removed in version 3.12: Part of the old-style Unicode API, please migrate to using
PyUnicode_GET_LENGTH().
PyUnicode_GET_DATA_SIZE(PyObject *o)Return the size of the deprecated Py_UNICODE representation in
bytes. o has to be a Unicode object (not checked).
Deprecated since version 3.3, will be removed in version 3.12: Part of the old-style Unicode API, please migrate to using
PyUnicode_GET_LENGTH().
PyUnicode_AS_UNICODE(PyObject *o)PyUnicode_AS_DATA(PyObject *o)Return a pointer to a Py_UNICODE representation of the object. The
returned buffer is always terminated with an extra null code point. It
may also contain embedded null code points, which would cause the string
to be truncated when used in most C functions. The AS_DATA form
casts the pointer to const char *. The o argument has to be
a Unicode object (not checked).
Changed in version 3.3: This macro is now inefficient – because in many cases the
Py_UNICODE representation does not exist and needs to be created
– and can fail (return NULL with an exception set). Try to port the
code to use the new PyUnicode_nBYTE_DATA() macros or use
PyUnicode_WRITE() or PyUnicode_READ().
Deprecated since version 3.3, will be removed in version 3.12: Part of the old-style Unicode API, please migrate to using the
PyUnicode_nBYTE_DATA() family of macros.
Unicode provides many different character properties. The most often needed ones are available through these macros which are mapped to C functions depending on the Python configuration.
Py_UNICODE_ISSPACE(Py_UNICODE ch)1 or 0 depending on whether ch is a whitespace character.Py_UNICODE_ISLOWER(Py_UNICODE ch)1 or 0 depending on whether ch is a lowercase character.Py_UNICODE_ISUPPER(Py_UNICODE ch)1 or 0 depending on whether ch is an uppercase character.Py_UNICODE_ISTITLE(Py_UNICODE ch)1 or 0 depending on whether ch is a titlecase character.Py_UNICODE_ISLINEBREAK(Py_UNICODE ch)1 or 0 depending on whether ch is a linebreak character.Py_UNICODE_ISDECIMAL(Py_UNICODE ch)1 or 0 depending on whether ch is a decimal character.Py_UNICODE_ISDIGIT(Py_UNICODE ch)1 or 0 depending on whether ch is a digit character.Py_UNICODE_ISNUMERIC(Py_UNICODE ch)1 or 0 depending on whether ch is a numeric character.Py_UNICODE_ISALPHA(Py_UNICODE ch)1 or 0 depending on whether ch is an alphabetic character.Py_UNICODE_ISALNUM(Py_UNICODE ch)1 or 0 depending on whether ch is an alphanumeric character.Py_UNICODE_ISPRINTABLE(Py_UNICODE ch)1 or 0 depending on whether ch is a printable character. Nonprintable characters are those characters defined in the Unicode character database as “Other” or “Separator”, excepting the ASCII space (0x20) which is considered printable. (Note that printable characters in this context are those which should not be escaped when repr() is invoked on a string. It has no bearing on the handling of strings written to sys.stdout or sys.stderr.)These APIs can be used for fast direct character conversions:
Py_UNICODE_TOLOWER(Py_UNICODE ch)Return the character ch converted to lower case.
Deprecated since version 3.3: This function uses simple case mappings.
Py_UNICODE_TOUPPER(Py_UNICODE ch)Return the character ch converted to upper case.
Deprecated since version 3.3: This function uses simple case mappings.
Py_UNICODE_TOTITLE(Py_UNICODE ch)Return the character ch converted to title case.
Deprecated since version 3.3: This function uses simple case mappings.
Py_UNICODE_TODECIMAL(Py_UNICODE ch)-1 if this is not possible. This macro does not raise exceptions.Py_UNICODE_TODIGIT(Py_UNICODE ch)-1 if this is not possible. This macro does not raise exceptions.Py_UNICODE_TONUMERIC(Py_UNICODE ch)-1.0 if this is not possible. This macro does not raise exceptions.These APIs can be used to work with surrogates:
Py_UNICODE_IS_SURROGATE(ch)0xD800 <= ch <= 0xDFFF).Py_UNICODE_IS_HIGH_SURROGATE(ch)0xD800 <= ch <= 0xDBFF).Py_UNICODE_IS_LOW_SURROGATE(ch)0xDC00 <= ch <= 0xDFFF).Py_UNICODE_JOIN_SURROGATES(high, low)
To create Unicode objects and access their basic sequence properties, use these APIs:
PyUnicode_New(Py_ssize_t size, Py_UCS4 maxchar)Return value: New reference.
Create a new Unicode object. maxchar should be the true maximum code point to be placed in the string. As an approximation, it can be rounded up to the nearest value in the sequence 127, 255, 65535, 1114111.
This is the recommended way to allocate a new Unicode object. Objects created using this function are not resizable.
New in version 3.3.
PyUnicode_FromKindAndData(int kind, const void *buffer, Py_ssize_t size)Return value: New reference.
Create a new Unicode object with the given kind (possible values are
PyUnicode_1BYTE_KIND etc., as returned by
PyUnicode_KIND()). The buffer must point to an array of size
units of 1, 2 or 4 bytes per character, as given by the kind.
New in version 3.3.
PyUnicode_FromStringAndSize(const char *u, Py_ssize_t size)Return value: New reference.
Create a Unicode object from the char buffer u. The bytes will be
interpreted as being UTF-8 encoded. The buffer is copied into the new
object. If the buffer is not NULL, the return value might be a shared
object, i.e. modification of the data is not allowed.
If u is NULL, this function behaves like PyUnicode_FromUnicode()
with the buffer set to NULL. This usage is deprecated in favor of
PyUnicode_New().
PyUnicode_FromString(const char *u)Return value: New reference.
Create a Unicode object from a UTF-8 encoded null-terminated char buffer u.
PyUnicode_FromFormat(const char *format, ...)Return value: New reference.
Take a C printf()-style format string and a variable number of
arguments, calculate the size of the resulting Python Unicode string and return
a string with the values formatted into it. The variable arguments must be C
types and must correspond exactly to the format characters in the format
ASCII-encoded string. The following format characters are allowed:
Format Characters |
Type |
Comment |
|---|---|---|
|
n/a |
The literal % character. |
|
int |
A single character, represented as a C int. |
|
int |
Equivalent to
|
|
unsigned int |
Equivalent to
|
|
long |
Equivalent to
|
|
long |
Equivalent to
|
|
unsigned long |
Equivalent to
|
|
long long |
Equivalent to
|
|
long long |
Equivalent to
|
|
unsigned long long |
Equivalent to
|
|
Py_ssize_t |
Equivalent to
|
|
Py_ssize_t |
Equivalent to
|
|
size_t |
Equivalent to
|
|
int |
Equivalent to
|
|
int |
Equivalent to
|
|
const char* |
A null-terminated C character array. |
|
const void* |
The hex representation of a C pointer. Mostly equivalent to
printf yields.
|
|
PyObject* |
The result of calling
|
|
PyObject* |
A Unicode object. |
|
PyObject*, const char* |
A Unicode object (which may be
NULL).
|
|
PyObject* |
The result of calling
|
|
PyObject* |
The result of calling
|
An unrecognized format character causes all the rest of the format string to be copied as-is to the result string, and any extra arguments discarded.
Note
The width formatter unit is number of characters rather than bytes.
The precision formatter unit is number of bytes for "%s" and
"%V" (if the PyObject* argument is NULL), and a number of
characters for "%A", "%U", "%S", "%R" and "%V"
(if the PyObject* argument is not NULL).
For integer specifiers (d, u, ld, li, lu, lld, lli, llu, zd, zi, zu, i, x): the 0-conversion flag has effect even when a precision is given.
Changed in version 3.2: Support for "%lld" and "%llu" added.
Changed in version 3.3: Support for "%li", "%lli" and "%zi" added.
Changed in version 3.4: Support width and precision formatter for "%s", "%A", "%U",
"%V", "%S", "%R" added.
PyUnicode_FromFormatV(const char *format, va_list vargs)Return value: New reference.
Identical to PyUnicode_FromFormat() except that it takes exactly two
arguments.
PyUnicode_FromEncodedObject(PyObject *obj, const char *encoding, const char *errors)Return value: New reference.
Decode an encoded object obj to a Unicode object.
bytes, bytearray and other
bytes-like objects
are decoded according to the given encoding and using the error handling
defined by errors. Both can be NULL to have the interface use the default
values (see Built-in Codecs for details).
All other objects, including Unicode objects, cause a TypeError to be
set.
The API returns NULL if there was an error. The caller is responsible for
decref’ing the returned objects.
PyUnicode_GetLength(PyObject *unicode)Return the length of the Unicode object, in code points.
New in version 3.3.
PyUnicode_CopyCharacters(PyObject *to, Py_ssize_t to_start, PyObject *from, Py_ssize_t from_start, Py_ssize_t how_many)Copy characters from one Unicode object into another. This function performs
character conversion when necessary and falls back to memcpy() if
possible. Returns -1 and sets an exception on error, otherwise returns
the number of copied characters.
New in version 3.3.
PyUnicode_Fill(PyObject *unicode, Py_ssize_t start, Py_ssize_t length, Py_UCS4 fill_char)Fill a string with a character: write fill_char into
unicode[start:start+length].
Fail if fill_char is bigger than the string maximum character, or if the string has more than 1 reference.
Return the number of written character, or return -1 and raise an
exception on error.
New in version 3.3.
PyUnicode_WriteChar(PyObject *unicode, Py_ssize_t index, Py_UCS4 character)Write a character to a string. The string must have been created through
PyUnicode_New(). Since Unicode strings are supposed to be immutable,
the string must not be shared, or have been hashed yet.
This function checks that unicode is a Unicode object, that the index is not out of bounds, and that the object can be modified safely (i.e. that it its reference count is one).
New in version 3.3.
PyUnicode_ReadChar(PyObject *unicode, Py_ssize_t index)Read a character from a string. This function checks that unicode is a
Unicode object and the index is not out of bounds, in contrast to the macro
version PyUnicode_READ_CHAR().
New in version 3.3.
PyUnicode_Substring(PyObject *str, Py_ssize_t start, Py_ssize_t end)Return value: New reference.
Return a substring of str, from character index start (included) to character index end (excluded). Negative indices are not supported.
New in version 3.3.
PyUnicode_AsUCS4(PyObject *u, Py_UCS4 *buffer, Py_ssize_t buflen, int copy_null)Copy the string u into a UCS4 buffer, including a null character, if
copy_null is set. Returns NULL and sets an exception on error (in
particular, a SystemError if buflen is smaller than the length of
u). buffer is returned on success.
New in version 3.3.
PyUnicode_AsUCS4Copy(PyObject *u)Copy the string u into a new UCS4 buffer that is allocated using
PyMem_Malloc(). If this fails, NULL is returned with a
MemoryError set. The returned buffer always has an extra
null code point appended.
New in version 3.3.
Deprecated since version 3.3, will be removed in version 4.0.
These API functions are deprecated with the implementation of PEP 393. Extension modules can continue using them, as they will not be removed in Python 3.x, but need to be aware that their use can now cause performance and memory hits.
PyUnicode_FromUnicode(const Py_UNICODE *u, Py_ssize_t size)Return value: New reference.
Create a Unicode object from the Py_UNICODE buffer u of the given size. u
may be NULL which causes the contents to be undefined. It is the user’s
responsibility to fill in the needed data. The buffer is copied into the new
object.
If the buffer is not NULL, the return value might be a shared object.
Therefore, modification of the resulting Unicode object is only allowed when
u is NULL.
If the buffer is NULL, PyUnicode_READY() must be called once the
string content has been filled before using any of the access macros such as
PyUnicode_KIND().
Deprecated since version 3.3, will be removed in version 3.12: Part of the old-style Unicode API, please migrate to using
PyUnicode_FromKindAndData(), PyUnicode_FromWideChar(), or
PyUnicode_New().
PyUnicode_AsUnicode(PyObject *unicode)Return a read-only pointer to the Unicode object’s internal
Py_UNICODE buffer, or NULL on error. This will create the
Py_UNICODE* representation of the object if it is not yet
available. The buffer is always terminated with an extra null code point.
Note that the resulting Py_UNICODE string may also contain
embedded null code points, which would cause the string to be truncated when
used in most C functions.
Deprecated since version 3.3, will be removed in version 3.12: Part of the old-style Unicode API, please migrate to using
PyUnicode_AsUCS4(), PyUnicode_AsWideChar(),
PyUnicode_ReadChar() or similar new APIs.
Deprecated since version 3.3, will be removed in version 3.10.
PyUnicode_TransformDecimalToASCII(Py_UNICODE *s, Py_ssize_t size)Return value: New reference.
Create a Unicode object by replacing all decimal digits in
Py_UNICODE buffer of the given size by ASCII digits 0–9
according to their decimal value. Return NULL if an exception occurs.
PyUnicode_AsUnicodeAndSize(PyObject *unicode, Py_ssize_t *size)Like PyUnicode_AsUnicode(), but also saves the Py_UNICODE()
array length (excluding the extra null terminator) in size.
Note that the resulting Py_UNICODE* string
may contain embedded null code points, which would cause the string to be
truncated when used in most C functions.
New in version 3.3.
Deprecated since version 3.3, will be removed in version 3.12: Part of the old-style Unicode API, please migrate to using
PyUnicode_AsUCS4(), PyUnicode_AsWideChar(),
PyUnicode_ReadChar() or similar new APIs.
PyUnicode_AsUnicodeCopy(PyObject *unicode)Create a copy of a Unicode string ending with a null code point. Return NULL
and raise a MemoryError exception on memory allocation failure,
otherwise return a new allocated buffer (use PyMem_Free() to free
the buffer). Note that the resulting Py_UNICODE* string may
contain embedded null code points, which would cause the string to be
truncated when used in most C functions.
New in version 3.2.
Please migrate to using PyUnicode_AsUCS4Copy() or similar new APIs.
PyUnicode_GetSize(PyObject *unicode)Return the size of the deprecated Py_UNICODE representation, in
code units (this includes surrogate pairs as 2 units).
Deprecated since version 3.3, will be removed in version 3.12: Part of the old-style Unicode API, please migrate to using
PyUnicode_GET_LENGTH().
PyUnicode_FromObject(PyObject *obj)Return value: New reference.
Copy an instance of a Unicode subtype to a new true Unicode object if necessary. If obj is already a true Unicode object (not a subtype), return the reference with incremented refcount.
Objects other than Unicode or its subtypes will cause a TypeError.
The current locale encoding can be used to decode text from the operating system.
PyUnicode_DecodeLocaleAndSize(const char *str, Py_ssize_t len, const char *errors)Return value: New reference.
Decode a string from UTF-8 on Android and VxWorks, or from the current
locale encoding on other platforms. The supported
error handlers are "strict" and "surrogateescape"
(PEP 383). The decoder uses "strict" error handler if
errors is NULL. str must end with a null character but
cannot contain embedded null characters.
Use PyUnicode_DecodeFSDefaultAndSize() to decode a string from
Py_FileSystemDefaultEncoding (the locale encoding read at
Python startup).
This function ignores the Python UTF-8 mode.
See also
The Py_DecodeLocale() function.
New in version 3.3.
Changed in version 3.7: The function now also uses the current locale encoding for the
surrogateescape error handler, except on Android. Previously, Py_DecodeLocale()
was used for the surrogateescape, and the current locale encoding was
used for strict.
PyUnicode_DecodeLocale(const char *str, const char *errors)Return value: New reference.
Similar to PyUnicode_DecodeLocaleAndSize(), but compute the string
length using strlen().
New in version 3.3.
PyUnicode_EncodeLocale(PyObject *unicode, const char *errors)Return value: New reference.
Encode a Unicode object to UTF-8 on Android and VxWorks, or to the current
locale encoding on other platforms. The
supported error handlers are "strict" and "surrogateescape"
(PEP 383). The encoder uses "strict" error handler if
errors is NULL. Return a bytes object. unicode cannot
contain embedded null characters.
Use PyUnicode_EncodeFSDefault() to encode a string to
Py_FileSystemDefaultEncoding (the locale encoding read at
Python startup).
This function ignores the Python UTF-8 mode.
See also
The Py_EncodeLocale() function.
New in version 3.3.
Changed in version 3.7: The function now also uses the current locale encoding for the
surrogateescape error handler, except on Android. Previously,
Py_EncodeLocale()
was used for the surrogateescape, and the current locale encoding was
used for strict.
To encode and decode file names and other environment strings,
Py_FileSystemDefaultEncoding should be used as the encoding, and
Py_FileSystemDefaultEncodeErrors should be used as the error handler
(PEP 383 and PEP 529). To encode file names to bytes during
argument parsing, the "O&" converter should be used, passing
PyUnicode_FSConverter() as the conversion function:
PyUnicode_FSConverter(PyObject* obj, void* result)ParseTuple converter: encode str objects – obtained directly or
through the os.PathLike interface – to bytes using
PyUnicode_EncodeFSDefault(); bytes objects are output as-is.
result must be a PyBytesObject* which must be released when it is
no longer used.
New in version 3.1.
Changed in version 3.6: Accepts a path-like object.
To decode file names to str during argument parsing, the "O&"
converter should be used, passing PyUnicode_FSDecoder() as the
conversion function:
PyUnicode_FSDecoder(PyObject* obj, void* result)ParseTuple converter: decode bytes objects – obtained either
directly or indirectly through the os.PathLike interface – to
str using PyUnicode_DecodeFSDefaultAndSize(); str
objects are output as-is. result must be a PyUnicodeObject* which
must be released when it is no longer used.
New in version 3.2.
Changed in version 3.6: Accepts a path-like object.
PyUnicode_DecodeFSDefaultAndSize(const char *s, Py_ssize_t size)Return value: New reference.
Decode a string using Py_FileSystemDefaultEncoding and the
Py_FileSystemDefaultEncodeErrors error handler.
If Py_FileSystemDefaultEncoding is not set, fall back to the
locale encoding.
Py_FileSystemDefaultEncoding is initialized at startup from the
locale encoding and cannot be modified later. If you need to decode a string
from the current locale encoding, use
PyUnicode_DecodeLocaleAndSize().
See also
The Py_DecodeLocale() function.
Changed in version 3.6: Use Py_FileSystemDefaultEncodeErrors error handler.
PyUnicode_DecodeFSDefault(const char *s)Return value: New reference.
Decode a null-terminated string using Py_FileSystemDefaultEncoding
and the Py_FileSystemDefaultEncodeErrors error handler.
If Py_FileSystemDefaultEncoding is not set, fall back to the
locale encoding.
Use PyUnicode_DecodeFSDefaultAndSize() if you know the string length.
Changed in version 3.6: Use Py_FileSystemDefaultEncodeErrors error handler.
PyUnicode_EncodeFSDefault(PyObject *unicode)Return value: New reference.
Encode a Unicode object to Py_FileSystemDefaultEncoding with the
Py_FileSystemDefaultEncodeErrors error handler, and return
bytes. Note that the resulting bytes object may contain
null bytes.
If Py_FileSystemDefaultEncoding is not set, fall back to the
locale encoding.
Py_FileSystemDefaultEncoding is initialized at startup from the
locale encoding and cannot be modified later. If you need to encode a string
to the current locale encoding, use PyUnicode_EncodeLocale().
See also
The Py_EncodeLocale() function.
New in version 3.2.
Changed in version 3.6: Use Py_FileSystemDefaultEncodeErrors error handler.
wchar_t support for platforms which support it:
PyUnicode_FromWideChar(const wchar_t *w, Py_ssize_t size)Return value: New reference.
Create a Unicode object from the wchar_t buffer w of the given size.
Passing -1 as the size indicates that the function must itself compute the length,
using wcslen.
Return NULL on failure.
PyUnicode_AsWideChar(PyObject *unicode, wchar_t *w, Py_ssize_t size)wchar_t buffer w. At most size wchar_t characters are copied (excluding a possibly trailing null termination character). Return the number of wchar_t characters copied or -1 in case of an error. Note that the resulting wchar_t* string may or may not be null-terminated. It is the responsibility of the caller to make sure that the wchar_t* string is null-terminated in case this is required by the application. Also, note that the wchar_t* string might contain null characters, which would cause the string to be truncated when used with most C functions.PyUnicode_AsWideCharString(PyObject *unicode, Py_ssize_t *size)Convert the Unicode object to a wide character string. The output string
always ends with a null character. If size is not NULL, write the number
of wide characters (excluding the trailing null termination character) into
*size. Note that the resulting wchar_t string might contain
null characters, which would cause the string to be truncated when used with
most C functions. If size is NULL and the wchar_t* string
contains null characters a ValueError is raised.
Returns a buffer allocated by PyMem_Alloc() (use
PyMem_Free() to free it) on success. On error, returns NULL
and *size is undefined. Raises a MemoryError if memory allocation
is failed.
New in version 3.2.
Changed in version 3.7: Raises a ValueError if size is NULL and the wchar_t*
string contains null characters.
Python provides a set of built-in codecs which are written in C for speed. All of these codecs are directly usable via the following functions.
Many of the following APIs take two arguments encoding and errors, and they
have the same semantics as the ones of the built-in str() string object
constructor.
Setting encoding to NULL causes the default encoding to be used
which is ASCII. The file system calls should use
PyUnicode_FSConverter() for encoding file names. This uses the
variable Py_FileSystemDefaultEncoding internally. This
variable should be treated as read-only: on some systems, it will be a
pointer to a static string, on others, it will change at run-time
(such as when the application invokes setlocale).
Error handling is set by errors which may also be set to NULL meaning to use
the default handling defined for the codec. Default error handling for all
built-in codecs is “strict” (ValueError is raised).
The codecs all use a similar interface. Only deviation from the following generic ones are documented for simplicity.
These are the generic codec APIs:
PyUnicode_Decode(const char *s, Py_ssize_t size, const char *encoding, const char *errors)Return value: New reference.
Create a Unicode object by decoding size bytes of the encoded string s.
encoding and errors have the same meaning as the parameters of the same name
in the str() built-in function. The codec to be used is looked up
using the Python codec registry. Return NULL if an exception was raised by
the codec.
PyUnicode_AsEncodedString(PyObject *unicode, const char *encoding, const char *errors)Return value: New reference.
Encode a Unicode object and return the result as Python bytes object.
encoding and errors have the same meaning as the parameters of the same
name in the Unicode encode() method. The codec to be used is looked up
using the Python codec registry. Return NULL if an exception was raised by
the codec.
PyUnicode_Encode(const Py_UNICODE *s, Py_ssize_t size, const char *encoding, const char *errors)Return value: New reference.
Encode the Py_UNICODE buffer s of the given size and return a Python
bytes object. encoding and errors have the same meaning as the
parameters of the same name in the Unicode encode() method. The codec
to be used is looked up using the Python codec registry. Return NULL if an
exception was raised by the codec.
Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using
PyUnicode_AsEncodedString().
These are the UTF-8 codec APIs:
PyUnicode_DecodeUTF8(const char *s, Py_ssize_t size, const char *errors)Return value: New reference.
Create a Unicode object by decoding size bytes of the UTF-8 encoded string
s. Return NULL if an exception was raised by the codec.
PyUnicode_DecodeUTF8Stateful(const char *s, Py_ssize_t size, const char *errors, Py_ssize_t *consumed)Return value: New reference.
If consumed is NULL, behave like PyUnicode_DecodeUTF8(). If
consumed is not NULL, trailing incomplete UTF-8 byte sequences will not be
treated as an error. Those bytes will not be decoded and the number of bytes
that have been decoded will be stored in consumed.
PyUnicode_AsUTF8String(PyObject *unicode)Return value: New reference.
Encode a Unicode object using UTF-8 and return the result as Python bytes
object. Error handling is “strict”. Return NULL if an exception was
raised by the codec.
PyUnicode_AsUTF8AndSize(PyObject *unicode, Py_ssize_t *size)Return a pointer to the UTF-8 encoding of the Unicode object, and
store the size of the encoded representation (in bytes) in size. The
size argument can be NULL; in this case no size will be stored. The
returned buffer always has an extra null byte appended (not included in
size), regardless of whether there are any other null code points.
In the case of an error, NULL is returned with an exception set and no
size is stored.
This caches the UTF-8 representation of the string in the Unicode object, and subsequent calls will return a pointer to the same buffer. The caller is not responsible for deallocating the buffer.
New in version 3.3.
Changed in version 3.7: The return type is now const char * rather of char *.
PyUnicode_AsUTF8(PyObject *unicode)As PyUnicode_AsUTF8AndSize(), but does not store the size.
New in version 3.3.
Changed in version 3.7: The return type is now const char * rather of char *.
PyUnicode_EncodeUTF8(const Py_UNICODE *s, Py_ssize_t size, const char *errors)Return value: New reference.
Encode the Py_UNICODE buffer s of the given size using UTF-8 and
return a Python bytes object. Return NULL if an exception was raised by
the codec.
Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using
PyUnicode_AsUTF8String(), PyUnicode_AsUTF8AndSize() or
PyUnicode_AsEncodedString().
These are the UTF-32 codec APIs:
PyUnicode_DecodeUTF32(const char *s, Py_ssize_t size, const char *errors, int *byteorder)Return value: New reference.
Decode size bytes from a UTF-32 encoded buffer string and return the
corresponding Unicode object. errors (if non-NULL) defines the error
handling. It defaults to “strict”.
If byteorder is non-NULL, the decoder starts decoding using the given byte
order:
*byteorder == -1: little endian
*byteorder == 0: native order
*byteorder == 1: big endian
If *byteorder is zero, and the first four bytes of the input data are a
byte order mark (BOM), the decoder switches to this byte order and the BOM is
not copied into the resulting Unicode string. If *byteorder is -1 or
1, any byte order mark is copied to the output.
After completion, *byteorder is set to the current byte order at the end of input data.
If byteorder is NULL, the codec starts in native order mode.
Return NULL if an exception was raised by the codec.
PyUnicode_DecodeUTF32Stateful(const char *s, Py_ssize_t size, const char *errors, int *byteorder, Py_ssize_t *consumed)Return value: New reference.
If consumed is NULL, behave like PyUnicode_DecodeUTF32(). If
consumed is not NULL, PyUnicode_DecodeUTF32Stateful() will not treat
trailing incomplete UTF-32 byte sequences (such as a number of bytes not divisible
by four) as an error. Those bytes will not be decoded and the number of bytes
that have been decoded will be stored in consumed.
PyUnicode_AsUTF32String(PyObject *unicode)Return value: New reference.
Return a Python byte string using the UTF-32 encoding in native byte
order. The string always starts with a BOM mark. Error handling is “strict”.
Return NULL if an exception was raised by the codec.
PyUnicode_EncodeUTF32(const Py_UNICODE *s, Py_ssize_t size, const char *errors, int byteorder)Return value: New reference.
Return a Python bytes object holding the UTF-32 encoded value of the Unicode data in s. Output is written according to the following byte order:
byteorder == -1: little endian
byteorder == 0: native byte order (writes a BOM mark)
byteorder == 1: big endian
If byteorder is 0, the output string will always start with the Unicode BOM
mark (U+FEFF). In the other two modes, no BOM mark is prepended.
If Py_UNICODE_WIDE is not defined, surrogate pairs will be output
as a single code point.
Return NULL if an exception was raised by the codec.
Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using
PyUnicode_AsUTF32String() or PyUnicode_AsEncodedString().
These are the UTF-16 codec APIs:
PyUnicode_DecodeUTF16(const char *s, Py_ssize_t size, const char *errors, int *byteorder)Return value: New reference.
Decode size bytes from a UTF-16 encoded buffer string and return the
corresponding Unicode object. errors (if non-NULL) defines the error
handling. It defaults to “strict”.
If byteorder is non-NULL, the decoder starts decoding using the given byte
order:
*byteorder == -1: little endian
*byteorder == 0: native order
*byteorder == 1: big endian
If *byteorder is zero, and the first two bytes of the input data are a
byte order mark (BOM), the decoder switches to this byte order and the BOM is
not copied into the resulting Unicode string. If *byteorder is -1 or
1, any byte order mark is copied to the output (where it will result in
either a \ufeff or a \ufffe character).
After completion, *byteorder is set to the current byte order at the end of input data.
If byteorder is NULL, the codec starts in native order mode.
Return NULL if an exception was raised by the codec.
PyUnicode_DecodeUTF16Stateful(const char *s, Py_ssize_t size, const char *errors, int *byteorder, Py_ssize_t *consumed)Return value: New reference.
If consumed is NULL, behave like PyUnicode_DecodeUTF16(). If
consumed is not NULL, PyUnicode_DecodeUTF16Stateful() will not treat
trailing incomplete UTF-16 byte sequences (such as an odd number of bytes or a
split surrogate pair) as an error. Those bytes will not be decoded and the
number of bytes that have been decoded will be stored in consumed.
PyUnicode_AsUTF16String(PyObject *unicode)Return value: New reference.
Return a Python byte string using the UTF-16 encoding in native byte
order. The string always starts with a BOM mark. Error handling is “strict”.
Return NULL if an exception was raised by the codec.
PyUnicode_EncodeUTF16(const Py_UNICODE *s, Py_ssize_t size, const char *errors, int byteorder)Return value: New reference.
Return a Python bytes object holding the UTF-16 encoded value of the Unicode data in s. Output is written according to the following byte order:
byteorder == -1: little endian
byteorder == 0: native byte order (writes a BOM mark)
byteorder == 1: big endian
If byteorder is 0, the output string will always start with the Unicode BOM
mark (U+FEFF). In the other two modes, no BOM mark is prepended.
If Py_UNICODE_WIDE is defined, a single Py_UNICODE value may get
represented as a surrogate pair. If it is not defined, each Py_UNICODE
values is interpreted as a UCS-2 character.
Return NULL if an exception was raised by the codec.
Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using
PyUnicode_AsUTF16String() or PyUnicode_AsEncodedString().
These are the UTF-7 codec APIs:
PyUnicode_DecodeUTF7(const char *s, Py_ssize_t size, const char *errors)Return value: New reference.
Create a Unicode object by decoding size bytes of the UTF-7 encoded string
s. Return NULL if an exception was raised by the codec.
PyUnicode_DecodeUTF7Stateful(const char *s, Py_ssize_t size, const char *errors, Py_ssize_t *consumed)Return value: New reference.
If consumed is NULL, behave like PyUnicode_DecodeUTF7(). If
consumed is not NULL, trailing incomplete UTF-7 base-64 sections will not
be treated as an error. Those bytes will not be decoded and the number of
bytes that have been decoded will be stored in consumed.
PyUnicode_EncodeUTF7(const Py_UNICODE *s, Py_ssize_t size, int base64SetO, int base64WhiteSpace, const char *errors)Return value: New reference.
Encode the Py_UNICODE buffer of the given size using UTF-7 and
return a Python bytes object. Return NULL if an exception was raised by
the codec.
If base64SetO is nonzero, “Set O” (punctuation that has no otherwise special meaning) will be encoded in base-64. If base64WhiteSpace is nonzero, whitespace will be encoded in base-64. Both are set to zero for the Python “utf-7” codec.
Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using
PyUnicode_AsEncodedString().
These are the “Unicode Escape” codec APIs:
PyUnicode_DecodeUnicodeEscape(const char *s, Py_ssize_t size, const char *errors)Return value: New reference.
Create a Unicode object by decoding size bytes of the Unicode-Escape encoded
string s. Return NULL if an exception was raised by the codec.
PyUnicode_AsUnicodeEscapeString(PyObject *unicode)Return value: New reference.
Encode a Unicode object using Unicode-Escape and return the result as a
bytes object. Error handling is “strict”. Return NULL if an exception was
raised by the codec.
PyUnicode_EncodeUnicodeEscape(const Py_UNICODE *s, Py_ssize_t size)Return value: New reference.
Encode the Py_UNICODE buffer of the given size using Unicode-Escape and
return a bytes object. Return NULL if an exception was raised by the codec.
Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using
PyUnicode_AsUnicodeEscapeString().
These are the “Raw Unicode Escape” codec APIs:
PyUnicode_DecodeRawUnicodeEscape(const char *s, Py_ssize_t size, const char *errors)Return value: New reference.
Create a Unicode object by decoding size bytes of the Raw-Unicode-Escape
encoded string s. Return NULL if an exception was raised by the codec.
PyUnicode_AsRawUnicodeEscapeString(PyObject *unicode)Return value: New reference.
Encode a Unicode object using Raw-Unicode-Escape and return the result as
a bytes object. Error handling is “strict”. Return NULL if an exception
was raised by the codec.
PyUnicode_EncodeRawUnicodeEscape(const Py_UNICODE *s, Py_ssize_t size)Return value: New reference.
Encode the Py_UNICODE buffer of the given size using Raw-Unicode-Escape
and return a bytes object. Return NULL if an exception was raised by the codec.
Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using
PyUnicode_AsRawUnicodeEscapeString() or
PyUnicode_AsEncodedString().
These are the Latin-1 codec APIs: Latin-1 corresponds to the first 256 Unicode ordinals and only these are accepted by the codecs during encoding.
PyUnicode_DecodeLatin1(const char *s, Py_ssize_t size, const char *errors)Return value: New reference.
Create a Unicode object by decoding size bytes of the Latin-1 encoded string
s. Return NULL if an exception was raised by the codec.
PyUnicode_AsLatin1String(PyObject *unicode)Return value: New reference.
Encode a Unicode object using Latin-1 and return the result as Python bytes
object. Error handling is “strict”. Return NULL if an exception was
raised by the codec.
PyUnicode_EncodeLatin1(const Py_UNICODE *s, Py_ssize_t size, const char *errors)Return value: New reference.
Encode the Py_UNICODE buffer of the given size using Latin-1 and
return a Python bytes object. Return NULL if an exception was raised by
the codec.
Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using
PyUnicode_AsLatin1String() or
PyUnicode_AsEncodedString().
These are the ASCII codec APIs. Only 7-bit ASCII data is accepted. All other codes generate errors.
PyUnicode_DecodeASCII(const char *s, Py_ssize_t size, const char *errors)Return value: New reference.
Create a Unicode object by decoding size bytes of the ASCII encoded string
s. Return NULL if an exception was raised by the codec.
PyUnicode_AsASCIIString(PyObject *unicode)Return value: New reference.
Encode a Unicode object using ASCII and return the result as Python bytes
object. Error handling is “strict”. Return NULL if an exception was
raised by the codec.
PyUnicode_EncodeASCII(const Py_UNICODE *s, Py_ssize_t size, const char *errors)Return value: New reference.
Encode the Py_UNICODE buffer of the given size using ASCII and
return a Python bytes object. Return NULL if an exception was raised by
the codec.
Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using
PyUnicode_AsASCIIString() or
PyUnicode_AsEncodedString().
This codec is special in that it can be used to implement many different codecs
(and this is in fact what was done to obtain most of the standard codecs
included in the encodings package). The codec uses mapping to encode and
decode characters. The mapping objects provided must support the
__getitem__() mapping interface; dictionaries and sequences work well.
These are the mapping codec APIs:
PyUnicode_DecodeCharmap(const char *data, Py_ssize_t size, PyObject *mapping, const char *errors)Return value: New reference.
Create a Unicode object by decoding size bytes of the encoded string s
using the given mapping object. Return NULL if an exception was raised
by the codec.
If mapping is NULL, Latin-1 decoding will be applied. Else
mapping must map bytes ordinals (integers in the range from 0 to 255)
to Unicode strings, integers (which are then interpreted as Unicode
ordinals) or None. Unmapped data bytes – ones which cause a
LookupError, as well as ones which get mapped to None,
0xFFFE or '\ufffe', are treated as undefined mappings and cause
an error.
PyUnicode_AsCharmapString(PyObject *unicode, PyObject *mapping)Return value: New reference.
Encode a Unicode object using the given mapping object and return the
result as a bytes object. Error handling is “strict”. Return NULL if an
exception was raised by the codec.
The mapping object must map Unicode ordinal integers to bytes objects,
integers in the range from 0 to 255 or None. Unmapped character
ordinals (ones which cause a LookupError) as well as mapped to
None are treated as “undefined mapping” and cause an error.
PyUnicode_EncodeCharmap(const Py_UNICODE *s, Py_ssize_t size, PyObject *mapping, const char *errors)Return value: New reference.
Encode the Py_UNICODE buffer of the given size using the given
mapping object and return the result as a bytes object. Return NULL if
an exception was raised by the codec.
Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using
PyUnicode_AsCharmapString() or
PyUnicode_AsEncodedString().
The following codec API is special in that maps Unicode to Unicode.
PyUnicode_Translate(PyObject *str, PyObject *table, const char *errors)Return value: New reference.
Translate a string by applying a character mapping table to it and return the
resulting Unicode object. Return NULL if an exception was raised by the
codec.
The mapping table must map Unicode ordinal integers to Unicode ordinal integers
or None (causing deletion of the character).
Mapping tables need only provide the __getitem__() interface; dictionaries
and sequences work well. Unmapped character ordinals (ones which cause a
LookupError) are left untouched and are copied as-is.
errors has the usual meaning for codecs. It may be NULL which indicates to
use the default error handling.
PyUnicode_TranslateCharmap(const Py_UNICODE *s, Py_ssize_t size, PyObject *mapping, const char *errors)Return value: New reference.
Translate a Py_UNICODE buffer of the given size by applying a
character mapping table to it and return the resulting Unicode object.
Return NULL when an exception was raised by the codec.
Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using
PyUnicode_Translate(). or generic codec based API
These are the MBCS codec APIs. They are currently only available on Windows and use the Win32 MBCS converters to implement the conversions. Note that MBCS (or DBCS) is a class of encodings, not just one. The target encoding is defined by the user settings on the machine running the codec.
PyUnicode_DecodeMBCS(const char *s, Py_ssize_t size, const char *errors)Return value: New reference.
Create a Unicode object by decoding size bytes of the MBCS encoded string s.
Return NULL if an exception was raised by the codec.
PyUnicode_DecodeMBCSStateful(const char *s, Py_ssize_t size, const char *errors, Py_ssize_t *consumed)Return value: New reference.
If consumed is NULL, behave like PyUnicode_DecodeMBCS(). If
consumed is not NULL, PyUnicode_DecodeMBCSStateful() will not decode
trailing lead byte and the number of bytes that have been decoded will be stored
in consumed.
PyUnicode_AsMBCSString(PyObject *unicode)Return value: New reference.
Encode a Unicode object using MBCS and return the result as Python bytes
object. Error handling is “strict”. Return NULL if an exception was
raised by the codec.
PyUnicode_EncodeCodePage(int code_page, PyObject *unicode, const char *errors)Return value: New reference.
Encode the Unicode object using the specified code page and return a Python
bytes object. Return NULL if an exception was raised by the codec. Use
CP_ACP code page to get the MBCS encoder.
New in version 3.3.
PyUnicode_EncodeMBCS(const Py_UNICODE *s, Py_ssize_t size, const char *errors)Return value: New reference.
Encode the Py_UNICODE buffer of the given size using MBCS and return
a Python bytes object. Return NULL if an exception was raised by the
codec.
Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using
PyUnicode_AsMBCSString(), PyUnicode_EncodeCodePage() or
PyUnicode_AsEncodedString().
The following APIs are capable of handling Unicode objects and strings on input (we refer to them as strings in the descriptions) and return Unicode objects or integers as appropriate.
They all return NULL or -1 if an exception occurs.
PyUnicode_Concat(PyObject *left, PyObject *right)Return value: New reference.
Concat two strings giving a new Unicode string.
PyUnicode_Split(PyObject *s, PyObject *sep, Py_ssize_t maxsplit)Return value: New reference.
Split a string giving a list of Unicode strings. If sep is NULL, splitting
will be done at all whitespace substrings. Otherwise, splits occur at the given
separator. At most maxsplit splits will be done. If negative, no limit is
set. Separators are not included in the resulting list.
PyUnicode_Splitlines(PyObject *s, int keepend)Return value: New reference.
Split a Unicode string at line breaks, returning a list of Unicode strings.
CRLF is considered to be one line break. If keepend is 0, the Line break
characters are not included in the resulting strings.
PyUnicode_Join(PyObject *separator, PyObject *seq)Return value: New reference.
Join a sequence of strings using the given separator and return the resulting Unicode string.
PyUnicode_Tailmatch(PyObject *str, PyObject *substr, Py_ssize_t start, Py_ssize_t end, int direction)1 if substr matches str[start:end] at the given tail end (direction == -1 means to do a prefix match, direction == 1 a suffix match), 0 otherwise. Return -1 if an error occurred.PyUnicode_Find(PyObject *str, PyObject *substr, Py_ssize_t start, Py_ssize_t end, int direction)str[start:end] using the given direction (direction == 1 means to do a forward search, direction == -1 a backward search). The return value is the index of the first match; a value of -1 indicates that no match was found, and -2 indicates that an error occurred and an exception has been set.PyUnicode_FindChar(PyObject *str, Py_UCS4 ch, Py_ssize_t start, Py_ssize_t end, int direction)Return the first position of the character ch in str[start:end] using
the given direction (direction == 1 means to do a forward search,
direction == -1 a backward search). The return value is the index of the
first match; a value of -1 indicates that no match was found, and -2
indicates that an error occurred and an exception has been set.
New in version 3.3.
Changed in version 3.7: start and end are now adjusted to behave like str[start:end].
PyUnicode_Count(PyObject *str, PyObject *substr, Py_ssize_t start, Py_ssize_t end)str[start:end]. Return -1 if an error occurred.PyUnicode_Replace(PyObject *str, PyObject *substr, PyObject *replstr, Py_ssize_t maxcount)Return value: New reference.
Replace at most maxcount occurrences of substr in str with replstr and
return the resulting Unicode object. maxcount == -1 means replace all
occurrences.
PyUnicode_Compare(PyObject *left, PyObject *right)Compare two strings and return -1, 0, 1 for less than, equal, and greater than,
respectively.
This function returns -1 upon failure, so one should call
PyErr_Occurred() to check for errors.
PyUnicode_CompareWithASCIIString(PyObject *uni, const char *string)Compare a Unicode object, uni, with string and return -1, 0, 1 for less
than, equal, and greater than, respectively. It is best to pass only
ASCII-encoded strings, but the function interprets the input string as
ISO-8859-1 if it contains non-ASCII characters.
This function does not raise exceptions.
PyUnicode_RichCompare(PyObject *left, PyObject *right, int op)Return value: New reference.
Rich compare two Unicode strings and return one of the following:
NULL in case an exception was raised
Py_True or Py_False for successful comparisons
Py_NotImplemented in case the type combination is unknown
Possible values for op are Py_GT, Py_GE, Py_EQ,
Py_NE, Py_LT, and Py_LE.
PyUnicode_Format(PyObject *format, PyObject *args)Return value: New reference.
Return a new string object from format and args; this is analogous to
format % args.
PyUnicode_Contains(PyObject *container, PyObject *element)Check whether element is contained in container and return true or false accordingly.
element has to coerce to a one element Unicode string. -1 is returned
if there was an error.
PyUnicode_InternInPlace(PyObject **string)PyUnicode_InternFromString(const char *v)Return value: New reference.
A combination of PyUnicode_FromString() and
PyUnicode_InternInPlace(), returning either a new Unicode string
object that has been interned, or a new (“owned”) reference to an earlier
interned string object with the same value.