indices = [i for i, s in enumerate(mylist) if 'aa' in s]
Your idea to use enumerate() was correct.
enumerate()
indices = []for i, elem in enumerate(mylist): if 'aa' in elem: indices.append(i)
Alternatively, as a list comprehension:
indices = [i for i, elem in enumerate(mylist) if 'aa' in elem]
Without enumerate():
>>> mylist = ["aa123", "bb2322", "aa354", "cc332", "ab334", "333aa"]>>> l = [mylist.index(i) for i in mylist if 'aa' in i]>>> l[0, 2, 5]