This module defines a new object type which can efficiently 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 type code, which is a single character. The following type codes are defined:
|Type code||C Type||Minimum size in bytes|
The actual representation of values is determined by the machine
architecture (strictly speaking, by the C implementation). The actual
size can be accessed through the itemsize attribute. The values
'I' items will be represented as
Python long integers when retrieved, because Python's plain integer
type cannot represent the full range of C's unsigned (long) integers.
The module defines the following function and type object:
Array objects support the following data items and methods:
(address, length)giving the current memory address and the length in bytes of the buffer used to hold array's contents. This is occasionally useful when working with low-level (and inherently unsafe) I/O interfaces that require memory addresses, such as certain ioctl() operations. The returned numbers are valid as long as the array exists and no length-changing operations are applied to it.
Read n items (as machine values) from the file object f and append them to the end of the array. If less than n items are available, EOFError is raised, but the items that were available are still inserted into the array. f must be a real built-in file object; something else with a read() method won't do.
Write all items (as machine values) to the file object f.
When an array object is printed or converted to a string, it is
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 array with the same type and value using reverse quotes
``), so long as the array() function has been
imported using "from array import array". Examples:
array('l') array('c', 'hello world') array('l', [1, 2, 3, 4, 5]) array('d', [1.0, 2.0, 3.14])
The Numeric Python extension (NumPy) defines another array type; see The Numerical Python Manual for additional information (available online at ftp://ftp-icf.llnl.gov/pub/python/numericalpython.pdf). Further information about NumPy is available at http://www.python.org/topics/scicomp/numpy.html.