lambda函数中匹配括号字符的索引?

我懒得担心角落里的案子,但使用 itertools.accumulate

f = lambda s,i: next((i for i,x in enumerate(accumulate
    ({'(': 1, ')': -1}.get(c,0) for c in s[i:]), i) if not x), None)

In [31]: s = '(() foo ) bar'

In [32]: f(s, 0)
Out[32]: 8

In [33]: f(s, 1)
Out[33]: 2

In [34]: f(s, 2)

这通过跟踪字符串的高度来工作,计数(作为+1和)作为-1:

In [36]: list(accumulate({'(': 1, ')': -1}.get(c,0) for c in s))
Out[36]: [1, 2, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0]