python - 如何通过删除python中的重复项进行压缩？

Question

我有包含相同字符 block 的字符串，例如 '1254,,,,,,,,,,,,,,,,982'。我的目标是将其替换为类似“1254(,16)982”的内容，以便可以重建原始字符串。如果有人能指出我正确的方向，将不胜感激

Answer 1

您正在寻找 run-length encoding : 这是一个松散地基于 this one 的 Python 实现.

import itertools

def runlength_enc(s):
    '''Return a run-length encoded version of the string'''
    enc = ((x, sum(1 for _ in gp)) for x, gp in itertools.groupby(s))
    removed_1s = [((c, n) if n > 1 else c) for c, n in enc]
    joined = [["".join(g)] if n == 1 else list(g)
                    for n, g in itertools.groupby(removed_1s, key=len)]
    return list(itertools.chain(*joined))

def runlength_decode(enc):
    return "".join((c[0] * c[1] if len(c) == 2 else c) for c in enc)

以你的例子为例:

print runlength_enc("1254,,,,,,,,,,,,,,,,982")
# ['1254', (',', 16), '982']
print runlength_decode(runlength_enc("1254,,,,,,,,,,,,,,,,982"))
# 1254,,,,,,,,,,,,,,,,982

(请注意，只有当您的字符串中有很长的运行时，这才会有效)。