A detailed description of the array array module used in Python

Initialization
An array instantiation can provide a parameter to describe which data type is allowed, and an initial data sequence can be stored in an array.

Import Arrayimport Binasciis = ' This is the array. ' A = Array.array (' C ', s) print ' As String: ', Sprint ' as array: ', Aprint ' As Hex  : ', Binascii.hexlify (a)

The array is configured to contain a sequence of bytes initialized with a simple string.

>>> ================================ RESTART ================================>>> as String:this is The array. As Array:array (' C ', ' This is the array. ') As Hex  : 54686973206973207468652061727261792e

Working with arrays
Similar to other Python sequences, you can extend and work with arrays in the same way.

Import Arrayimport Pprinta = Array.array (' i ', xrange (3)) print ' Initial: ', Aa.extend (xrange (3)) print ' Extended: ', Aprint ' Slice:: ', A[2:5]print ' itetator: ' Print List ' (Enumerate (a))

Supported operations include sharding, iterating, and adding elements to the end.

>>> ================================ RESTART ================================>>> initial:array (' I ', [0, 1, 2]) Extended:array (' i ', [0, 1, 2, 0, 1, 2]) Slice:: Array (' I ', [2, 0, 1]) itetator:[(0, 0), (1, 1), (2, 2), (3, 0), (4, 1), (5, 2)]

Arrays and files
You can use a dedicated built-in method of efficient read/write files to write the contents of an array to a file or read an array from a file.

Import arrayimport Binasciiimport Tempfilea = Array.array (' i ', xrange (5)) print ' A1: ', aoutput = Tempfile. Namedtemporaryfile () a.tofile (output.file) Output.flushwith open (Output.name, ' RB ') as input:  raw_input = Input.read ()  print ' Raw Contents: ', Binascii.hexlify (raw_data)  input.seek (0)  a2 = Array.array (' i ')  A2.fromfile (input, Len (a))  print ' A2: ', A2

Candidate byte order
If the data in the array does not have an intrinsic byte order, or if a swap order is required before sending to a system that takes a different byte order, the entire array can be transformed in Python without having to iterate over each element.

Import Arrayimport binasciidef To_hex (a):  Chars_per_item = a.itemsize * 2  hex_version = Binascii.hexlify (a)  num_chunks = Len (hex_version)/Chars_per_item for  i in Xrange (num_chunks):    start = i * Chars_per_item    E nd = start + chars_per_item    yield hex_version[start:end]a1 = Array.array (' i ', xrange (5)) a2 = Array.array (' i ', xrange ( 5) A2.byteswap () FMT = '%10s%10s%10s%10s ' Print fmt% (' A1_hex ', ' A1 ', ' a2_hex ', ' A2 ') print Fmt% (('-' * ' *) * 4) for VA Lue in Zip (To_hex (A1), A1, To_hex (A2), A2):  Print FMT% value

Byteswap () swaps the byte order of the elements in the C array, which is much more efficient than looping the data in Python.

>>> ================================ RESTART ================================>>>   A1_hex     A1   A2_hex     A2----------------------------------------00000000     0  00000000     0 01000000     1  00000001  16777216 02000000     2  00000002  33554432 03000000     3  00000003  50331648 04000000     4  00000004  67108864

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