Find common character in list of strings-CodePudding

I want to find common chars in given list of strings without using collections library. Can someone help on this?

Input:

strings = ["apple", "app", "ape"]

Output:

result - ap

CodePudding user response：

You example could have 3 interpretations: common char at any position, common chars at same position, or common chars at the beginning (all these would result in 'ap'):

To get common characters at any position, you can use a set intersection over all strings:

strings = ["apple", "app", "ape"]

common = set.intersection(*map(set,strings))

print(common) # {'p', 'a'}

To get common characters at the same positions:

strings = ["apple", "app", "ape"]

common = "".join(p for p,*r in zip(*strings) if all(p==c for c in r))

print(common) # ap

To get the longest common prefix (without libraries):

strings = ["apple", "app", "ape"]

common = next((i for i,(p,*r) in enumerate(zip(*strings)) 
                                 if any(p!=c for c in r)),0)

print(strings[0][:common]) # ap

CodePudding user response：

Like this:

strings = ["apple", "app", "ape"]

char_sets = [{*s} for s in strings]

result_set = char_sets[0]
for char_set in char_sets[1:]:
    result_set.intersection_update(char_set)

print(''.join(sorted(list(result_set))))

Returns:

ap

Assumed you need all common characters sorted.

CodePudding user response：

print({c for c in strings[0] if all(c in s for s in strings[1:])})