f | |
| :mod:`array` --- Efficient arrays of numeric values |
| =================================================== |
| |
| .. module:: array |
n | :synopsis: Efficient arrays of uniformly typed numeric values. |
n | :synopsis: Space efficient arrays of uniformly typed numeric values. |
| |
| |
| .. index:: single: arrays |
| |
n | This module defines an object type which can efficiently represent an array of |
n | This module defines an object type which can compactly represent an array of |
| basic values: characters, integers, floating point numbers. Arrays are sequence |
| types and behave very much like lists, except that the type of objects stored in |
| them is constrained. The type is specified at object creation time by using a |
| :dfn:`type code`, which is a single character. The following type codes are |
| defined: |
| |
| +-----------+----------------+-------------------+-----------------------+ |
| | Type code | C Type | Python Type | Minimum size in bytes | |
| exists and no length-changing operations are applied to it. |
| |
| .. note:: |
| |
| When using array objects from code written in C or C++ (the only way to |
| effectively make use of this information), it makes more sense to use the buffer |
| interface supported by array objects. This method is maintained for backward |
| compatibility and should be avoided in new code. The buffer interface is |
n | documented in the Python/C API Reference Manual (XXX reference: |
n | documented in :ref:`bufferobjects`. |
| ../api/newTypes.html). |
| |
| |
| .. method:: array.byteswap() |
| |
| "Byteswap" all items of the array. This is only supported for values which are |
| 1, 2, 4, or 8 bytes in size; for other types of values, :exc:`RuntimeError` is |
| raised. It is useful when reading data from a file written on a machine with a |
| different byte order. |
| .. method:: array.fromstring(s) |
| |
| Appends items from the string, interpreting the string as an array of machine |
| values (as if it had been read from a file using the :meth:`fromfile` method). |
| |
| |
| .. method:: array.fromunicode(s) |
| |
n | Extends this array with data from the given unicode string. The array must be a |
n | Extends this array with data from the given unicode string. The array must |
| type ``'u'`` array; otherwise a :exc:`ValueError` is raised. Use |
| be a type ``'u'`` array; otherwise a :exc:`ValueError` is raised. Use |
| ``array.fromstring(ustr.decode(enc))`` to append Unicode data to an array of |
| ``array.fromstring(unicodestring.encode(enc))`` to append Unicode data to an |
| some other type. |
| array of some other type. |
| |
| |
| .. method:: array.index(x) |
| |
| Return the smallest *i* such that *i* is the index of the first occurrence of |
| *x* in the array. |
| |
| |
| Use the :meth:`tofile` method. |
| |
| Write all items (as machine values) to the file object *f*. |
| |
| When an array object is printed or converted to a string, it is represented as |
| ``array(typecode, initializer)``. The *initializer* is omitted if the array is |
| empty, otherwise it is a string if the *typecode* is ``'c'``, otherwise it is a |
| list of numbers. The string is guaranteed to be able to be converted back to an |
n | array with the same type and value using reverse quotes (``````), so long as the |
n | array with the same type and value using :func:`eval`, so long as the |
| :func:`array` function has been imported using ``from array import array``. |
| Examples:: |
| |
| array('l') |
| array('c', 'hello world') |
n | array('u', u'hello \textbackslash u2641') |
n | array('u', u'hello \u2641') |
| array('l', [1, 2, 3, 4, 5]) |
| array('d', [1.0, 2.0, 3.14]) |
| |
| |
| .. seealso:: |
| |
| Module :mod:`struct` |
| Packing and unpacking of heterogeneous binary data. |
| |
| Module :mod:`xdrlib` |
| Packing and unpacking of External Data Representation (XDR) data as used in some |
| remote procedure call systems. |
| |
| `The Numerical Python Manual <http://numpy.sourceforge.net/numdoc/HTML/numdoc.htm>`_ |
| The Numeric Python extension (NumPy) defines another array type; see |
t | `<http://numpy.sourceforge.net/>`_ for further information about Numerical |
t | http://numpy.sourceforge.net/ for further information about Numerical Python. |
| Python. (A PDF version of the NumPy manual is available at |
| (A PDF version of the NumPy manual is available at |
| `<http://numpy.sourceforge.net/numdoc/numdoc.pdf>`_). |
| http://numpy.sourceforge.net/numdoc/numdoc.pdf). |
| |