python - 在找到常量后查找下一个模式

Question

我有一个单词列表，想知道下一个单词的位置或索引遵循某种模式（这是一个简单的例子，但正则表达式有点像魔鬼）

list = ["A","B","C","D","A","B","C","D","A","B","-","C","D"]

现在我找到了“A”的位置

a = [i for i,x in enumerate(list) if x == "A"]

但是，如果我想每次找到“A”时都找到“C”，然后递归地从下一个“A”重新开始。

Answer 1

list.index有一个可选参数start，您可以使用它来指定起始索引。

>>> lis = ["A","B","C","D","A","B","C","D","A","B","-","C","D"]
>>> for i,x in enumerate(lis):
...     if x == 'A':
...         print "next 'C' found at",lis.index('C',i)
...         
next 'C' found at 2
next 'C' found at 6
next 'C' found at 11

更新：

>>> import re
>>> strs =  "".join(lis)
>>> strs
'ABCDABCDAB-CD'
>>> r = re.compile(r'A[^C]+C')
>>> [m.end()-1 for m in r.finditer(strs)]
[2, 6, 11]
#or
>>> r = re.compile(r'A[^C]+')
>>> [m.end() for m in r.finditer(strs)]
[2, 6, 11]