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gh-98836: Extend PyUnicode_FromFormat() (GH-98838)
* Support for conversion specifiers o (octal) and X (uppercase hexadecimal). * Support for length modifiers j (intmax_t) and t (ptrdiff_t). * Length modifiers are now applied to all integer conversions. * Support for wchar_t C strings (%ls and %lV). * Support for variable width and precision (*). * Support for flag - (left alignment).
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‎Doc/c-api/unicode.rst‎

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@@ -394,98 +394,149 @@ APIs:
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arguments, calculate the size of the resulting Python Unicode string and return
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a string with the values formatted into it. The variable arguments must be C
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types and must correspond exactly to the format characters in the *format*
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ASCII-encoded string. The following format characters are allowed:
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.. % This should be exactly the same as the table in PyErr_Format.
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.. tabularcolumns:: |l|l|L|
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+-------------------+---------------------+----------------------------------+
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| Format Characters | Type | Comment |
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+===================+=====================+==================================+
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| :attr:`%%` | *n/a* | The literal % character. |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%c` | int | A single character, |
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| | | represented as a C int. |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%d` | int | Equivalent to |
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| | | ``printf("%d")``. [1]_ |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%u` | unsigned int | Equivalent to |
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| | | ``printf("%u")``. [1]_ |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%ld` | long | Equivalent to |
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| | | ``printf("%ld")``. [1]_ |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%li` | long | Equivalent to |
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| | | ``printf("%li")``. [1]_ |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%lu` | unsigned long | Equivalent to |
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| | | ``printf("%lu")``. [1]_ |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%lld` | long long | Equivalent to |
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| | | ``printf("%lld")``. [1]_ |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%lli` | long long | Equivalent to |
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| | | ``printf("%lli")``. [1]_ |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%llu` | unsigned long long | Equivalent to |
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| | | ``printf("%llu")``. [1]_ |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%zd` | :c:type:`\ | Equivalent to |
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| | Py_ssize_t` | ``printf("%zd")``. [1]_ |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%zi` | :c:type:`\ | Equivalent to |
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| | Py_ssize_t` | ``printf("%zi")``. [1]_ |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%zu` | size_t | Equivalent to |
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| | | ``printf("%zu")``. [1]_ |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%i` | int | Equivalent to |
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| | | ``printf("%i")``. [1]_ |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%x` | int | Equivalent to |
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| | | ``printf("%x")``. [1]_ |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%s` | const char\* | A null-terminated C character |
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| | | array. |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%p` | const void\* | The hex representation of a C |
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| | | pointer. Mostly equivalent to |
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| | | ``printf("%p")`` except that |
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| | | it is guaranteed to start with |
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| | | the literal ``0x`` regardless |
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| | | of what the platform's |
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| | | ``printf`` yields. |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%A` | PyObject\* | The result of calling |
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| | | :func:`ascii`. |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%U` | PyObject\* | A Unicode object. |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%V` | PyObject\*, | A Unicode object (which may be |
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| | const char\* | ``NULL``) and a null-terminated |
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| | | C character array as a second |
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| | | parameter (which will be used, |
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| | | if the first parameter is |
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| | | ``NULL``). |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%S` | PyObject\* | The result of calling |
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| | | :c:func:`PyObject_Str`. |
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+-------------------+---------------------+----------------------------------+
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| :attr:`%R` | PyObject\* | The result of calling |
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| | | :c:func:`PyObject_Repr`. |
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+-------------------+---------------------+----------------------------------+
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ASCII-encoded string.
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A conversion specifier contains two or more characters and has the following
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components, which must occur in this order:
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#. The ``'%'`` character, which marks the start of the specifier.
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#. Conversion flags (optional), which affect the result of some conversion
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types.
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#. Minimum field width (optional).
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If specified as an ``'*'`` (asterisk), the actual width is given in the
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next argument, which must be of type :c:expr:`int`, and the object to
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convert comes after the minimum field width and optional precision.
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#. Precision (optional), given as a ``'.'`` (dot) followed by the precision.
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If specified as ``'*'`` (an asterisk), the actual precision is given in
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the next argument, which must be of type :c:expr:`int`, and the value to
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convert comes after the precision.
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#. Length modifier (optional).
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#. Conversion type.
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The conversion flag characters are:
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.. tabularcolumns:: |l|L|
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+-------+-------------------------------------------------------------+
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| Flag | Meaning |
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+=======+=============================================================+
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| ``0`` | The conversion will be zero padded for numeric values. |
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+-------+-------------------------------------------------------------+
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| ``-`` | The converted value is left adjusted (overrides the ``0`` |
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| | flag if both are given). |
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+-------+-------------------------------------------------------------+
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The length modifiers for following integer conversions (``d``, ``i``,
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``o``, ``u``, ``x``, or ``X``) specify the type of the argument
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(:c:expr:`int` by default):
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.. tabularcolumns:: |l|L|
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+----------+-----------------------------------------------------+
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| Modifier | Types |
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+==========+=====================================================+
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| ``l`` | :c:expr:`long` or :c:expr:`unsigned long` |
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+----------+-----------------------------------------------------+
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| ``ll`` | :c:expr:`long long` or :c:expr:`unsigned long long` |
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+----------+-----------------------------------------------------+
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| ``j`` | :c:expr:`intmax_t` or :c:expr:`uintmax_t` |
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+----------+-----------------------------------------------------+
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| ``z`` | :c:expr:`size_t` or :c:expr:`ssize_t` |
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+----------+-----------------------------------------------------+
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| ``t`` | :c:expr:`ptrdiff_t` |
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+----------+-----------------------------------------------------+
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The length modifier ``l`` for following conversions ``s`` or ``V`` specify
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that the type of the argument is :c:expr:`const wchar_t*`.
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The conversion specifiers are:
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.. list-table::
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:widths: auto
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:header-rows: 1
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* - Conversion Specifier
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- Type
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- Comment
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* - ``%``
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- *n/a*
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- The literal ``%`` character.
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* - ``d``, ``i``
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- Specified by the length modifier
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- The decimal representation of a signed C integer.
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* - ``u``
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- Specified by the length modifier
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- The decimal representation of an unsigned C integer.
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* - ``o``
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- Specified by the length modifier
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- The octal representation of an unsigned C integer.
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* - ``x``
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- Specified by the length modifier
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- The hexadecimal representation of an unsigned C integer (lowercase).
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* - ``X``
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- Specified by the length modifier
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- The hexadecimal representation of an unsigned C integer (uppercase).
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* - ``c``
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- :c:expr:`int`
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- A single character.
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* - ``s``
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- :c:expr:`const char*` or :c:expr:`const wchar_t*`
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- A null-terminated C character array.
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* - ``p``
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- :c:expr:`const void*`
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- The hex representation of a C pointer.
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Mostly equivalent to ``printf("%p")`` except that it is guaranteed to
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start with the literal ``0x`` regardless of what the platform's
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``printf`` yields.
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* - ``A``
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- :c:expr:`PyObject*`
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- The result of calling :func:`ascii`.
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* - ``U``
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- :c:expr:`PyObject*`
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- A Unicode object.
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* - ``V``
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- :c:expr:`PyObject*`, :c:expr:`const char*` or :c:expr:`const wchar_t*`
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- A Unicode object (which may be ``NULL``) and a null-terminated
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C character array as a second parameter (which will be used,
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if the first parameter is ``NULL``).
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* - ``S``
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- :c:expr:`PyObject*`
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- The result of calling :c:func:`PyObject_Str`.
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* - ``R``
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- :c:expr:`PyObject*`
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- The result of calling :c:func:`PyObject_Repr`.
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.. note::
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The width formatter unit is number of characters rather than bytes.
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The precision formatter unit is number of bytes for ``"%s"`` and
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The precision formatter unit is number of bytes or :c:expr:`wchar_t`
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items (if the length modifier ``l`` is used) for ``"%s"`` and
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``"%V"`` (if the ``PyObject*`` argument is ``NULL``), and a number of
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characters for ``"%A"``, ``"%U"``, ``"%S"``, ``"%R"`` and ``"%V"``
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(if the ``PyObject*`` argument is not ``NULL``).
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.. [1] For integer specifiers (d, u, ld, li, lu, lld, lli, llu, zd, zi,
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zu, i, x): the 0-conversion flag has effect even when a precision is given.
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.. note::
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Unlike to C :c:func:`printf` the ``0`` flag has effect even when
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a precision is given for integer conversions (``d``, ``i``, ``u``, ``o``,
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``x``, or ``X``).
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.. versionchanged:: 3.2
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Support for ``"%lld"`` and ``"%llu"`` added.
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``"%V"``, ``"%S"``, ``"%R"`` added.
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.. versionchanged:: 3.12
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Support for conversion specifiers ``o`` and ``X``.
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Support for length modifiers ``j`` and ``t``.
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Length modifiers are now applied to all integer conversions.
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Length modifier ``l`` is now applied to conversion specifiers ``s`` and ``V``.
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Support for variable width and precision ``*``.
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Support for flag ``-``.
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An unrecognized format character now sets a :exc:`SystemError`.
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In previous versions it caused all the rest of the format string to be
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copied as-is to the result string, and any extra arguments discarded.

‎Doc/whatsnew/3.12.rst‎

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:py:meth:`~class.__subclasses__` (using :c:func:`PyObject_CallMethod`,
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for example).
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* Add support of more formatting options (left aligning, octals, uppercase
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hexadecimals, ``intmax_t``, ``ptrdiff_t``, ``wchar_t`` C
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strings, variable width and precision) in :c:func:`PyUnicode_FromFormat` and
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:c:func:`PyUnicode_FromFormatV`.
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(Contributed by Serhiy Storchaka in :gh:`98836`.)
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* An unrecognized format character in :c:func:`PyUnicode_FromFormat` and
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:c:func:`PyUnicode_FromFormatV` now sets a :exc:`SystemError`.
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In previous versions it caused all the rest of the format string to be

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