如何删除包含在同一字符串列表中的其他字符串中的字符串？

Question

I have a list of strings and need to remove items contained in other items like shown:

a = ["one", "one single", "one single trick", "trick", "trick must", "trick must get", "one single trick must", "must get", "must get the job done"]

I just need to drop every string contained in another string in the same list, like: "one" is contained in "one single" so it must be dropped, then "one single" is contained in "one single trick" so also need to be dropped

I have tried:

b=a
for item in a:
    for element in b:
        if item in element:
            b.remove(element)

expected result:

a = ["trick must get", "one single trick must", "must get the job done"]

Any help will be greatly appreciated! Thanks in advance!

Answer 1

A list comprehension should do this quite nicely, combined with Python's any function:

a = [phrase for phrase in a if not any([phrase2 != phrase and phrase in phrase2 for phrase2 in a])]

result:

>>> a = ["one", "one single", "one single trick", "trick", "trick must", "trick must get", "one single trick must", "must get", "must get the job done"]
>>> a = [phrase for phrase in a if not any([phrase2 != phrase and phrase in phrase2 for phrase2 in a])]
>>> a
['trick must get', 'one single trick must', 'must get the job done']

Answer 2

An efficient approach to solve the problem in O(n) time complexity is to use a set that keeps track of all the sub-phrases given a phrase, iterate from the longest string to the shortest, and only add the string to the output if the it is not already in the set of sub-phrases:

seen = set()
output = []
for s in sorted(a, key=len, reverse=True):
    words = tuple(s.split())
    if words not in seen:
        output.append(s)
    seen.update({words[i: i + n] for i in range(len(words)) for n in range(len(words) - i + 1)})

output becomes:

['one single trick must', 'must get the job done', 'trick must get']

Answer 3

Not an efficient solution, but by sorting longest to smallest and removing the last element we can check if each appears as a sub string anywhere.

a = ['one', 'one single', 'one single trick', 'trick', 'trick must', 'trick must get', 
     'one single trick must', 'must get', 'must get the job done']
a = sorted(a, key=len, reverse=True)
b = []
for i in range(len(a)):
    x = a.pop()
    if x not in "\t".join(a):
        b.append(x)

# ['trick must get', 'must get the job done', 'one single trick must']