Python:已知子字符串序列，返回子字符串在原字符串的所有位置(indices)

A.循环

myDNA = 'CAAGAGAAACGCAAAGAAACUGACAGAAGAGAGUGAGCACACAAAGGCAAUUU'

substr = 'UGACAGAAGAGAGUGAGCAC'

indices = [i for i in xrange(len(myDNA)) if myDNA.startswith(substr, i)] 

print indices

结果是

[20]

B.正则表达式

import re

myDNA = 'CAAGAGAAACGCAAAGAAACUGACAGAAGAGAGUGAGCACACAAAGGCAAUUU'

substr = 'UGACAGAAGAGAGUGAGCAC'

indices = [m.start() for m in re.finditer(re.compile(substr), myDNA)]

方法B的问题是如果2个子字符串有重叠，则不能找出第二个子字符串的位置

比如

myDNA = 'ATATATA'

substr = 'ATA'

方法A得到 indices=[0,2,4]

方法B得到 indices=[0,4]

所以如果子字符串有重叠时，只能用方法A

references

Search substring in a string and get index of all occurances.reply1 reply2

Find All Indices of a SubString in a Given String