array — 固定类型的数据序列

初始化

# array_string.py
import array
import binascii

s = b'This is the array.'
a = array.array('b', s)

print('As byte string:', s)
print('As array      :', a)
print('As hex        :', binascii.hexlify(a))

操作数组

# array_sequence.py
import array
import pprint

a = array.array('i', range(3))
print('Initial :', a)

a.extend(range(3))
print('Extended:', a)

print('Slice   :', a[2:5])

print('Iterator:')
print(list(enumerate(a)))

数组和文件

# array_file.py
import array
import binascii
import tempfile

a = array.array('i', range(5))
print('A1:', a)

# Write the array of numbers to a temporary file
output = tempfile.NamedTemporaryFile()
a.tofile(output.file)  # must pass an *actual* file
output.flush()

# Read the raw data
with open(output.name, 'rb') as input:
    raw_data = input.read()
    print('Raw Contents:', binascii.hexlify(raw_data))

    # Read the data into an array
    input.seek(0)
    a2 = array.array('i')
    a2.fromfile(input, len(a))
    print('A2:', a2)

# array_tobytes.py
import array
import binascii

a = array.array('i', range(5))
print('A1:', a)

as_bytes = a.tobytes()
print('Bytes:', binascii.hexlify(as_bytes))

a2 = array.array('i')
a2.frombytes(as_bytes)
print('A2:', a2)

Alternative Byte Ordering

# array_byteswap.py
import array
import binascii


def to_hex(a):
    chars_per_item = a.itemsize * 2  # 2 hex digits
    hex_version = binascii.hexlify(a)
    num_chunks = len(hex_version) // chars_per_item
    for i in range(num_chunks):
        start = i * chars_per_item
        end = start + chars_per_item
        yield hex_version[start:end]


start = int('0x12345678', 16)
end = start + 5
a1 = array.array('i', range(start, end))
a2 = array.array('i', range(start, end))
a2.byteswap()

fmt = '{:>12} {:>12} {:>12} {:>12}'
print(fmt.format('A1 hex', 'A1', 'A2 hex', 'A2'))
print(fmt.format('-' * 12, '-' * 12, '-' * 12, '-' * 12))
fmt = '{!r:>12} {:12} {!r:>12} {:12}'
for values in zip(to_hex(a1), a1, to_hex(a2), a2):
    print(fmt.format(*values))