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:mod:`struct` -- pack and unpack primitive data types
=====================================================
.. module:: struct
:synopsis: pack and unpack primitive data types
|see_cpython_module| :mod:`python:struct`.
The following byte orders are supported:
+-----------+------------------------+----------+-----------+
| Character | Byte order | Size | Alignment |
+===========+========================+==========+===========+
| @ | native | native | native |
+-----------+------------------------+----------+-----------+
| < | little-endian | standard | none |
+-----------+------------------------+----------+-----------+
| > | big-endian | standard | none |
+-----------+------------------------+----------+-----------+
| ! | network (= big-endian) | standard | none |
+-----------+------------------------+----------+-----------+
The following data types are supported:
+--------+--------------------+-------------------+---------------+
| Format | C Type | Python type | Standard size |
+========+====================+===================+===============+
| b | signed char | integer | 1 |
+--------+--------------------+-------------------+---------------+
| B | unsigned char | integer | 1 |
+--------+--------------------+-------------------+---------------+
| h | short | integer | 2 |
+--------+--------------------+-------------------+---------------+
| H | unsigned short | integer | 2 |
+--------+--------------------+-------------------+---------------+
| i | int | integer (`1<fn>`) | 4 |
+--------+--------------------+-------------------+---------------+
| I | unsigned int | integer (`1<fn>`) | 4 |
+--------+--------------------+-------------------+---------------+
| l | long | integer (`1<fn>`) | 4 |
+--------+--------------------+-------------------+---------------+
| L | unsigned long | integer (`1<fn>`) | 4 |
+--------+--------------------+-------------------+---------------+
| q | long long | integer (`1<fn>`) | 8 |
+--------+--------------------+-------------------+---------------+
| Q | unsigned long long | integer (`1<fn>`) | 8 |
+--------+--------------------+-------------------+---------------+
| f | float | float (`2<fn>`) | 4 |
+--------+--------------------+-------------------+---------------+
| d | double | float (`2<fn>`) | 8 |
+--------+--------------------+-------------------+---------------+
| s | char[] | bytes | |
+--------+--------------------+-------------------+---------------+
| P | void * | integer | |
+--------+--------------------+-------------------+---------------+
.. _fn:
(1) Requires long support when used with values larger than 30 bits.
(2) Requires floating point support.
.. admonition:: Difference to CPython
:class: attention
Whitespace is not supported in format strings.
Functions
---------
.. function:: calcsize(fmt)
Return the number of bytes needed to store the given *fmt*.
.. function:: pack(fmt, v1, v2, ...)
Pack the values *v1*, *v2*, ... according to the format string *fmt*.
The return value is a bytes object encoding the values.
.. function:: pack_into(fmt, buffer, offset, v1, v2, ...)
Pack the values *v1*, *v2*, ... according to the format string *fmt*
into a *buffer* starting at *offset*. *offset* may be negative to count
from the end of *buffer*.
.. function:: unpack(fmt, data)
Unpack from the *data* according to the format string *fmt*.
The return value is a tuple of the unpacked values.
.. function:: unpack_from(fmt, data, offset=0, /)
Unpack from the *data* starting at *offset* according to the format string
*fmt*. *offset* may be negative to count from the end of *data*. The return
value is a tuple of the unpacked values.
|
