如何将一个字符串添加到另一个字符串并删除重叠的部分？

Question

How do I add one string to another and remove a part in the middle if it's double?

I really don't know how to explain this but this is what I want to do:

Lets say

string1 = "abcde"

string2 = "cdefg"

How would I create a variable that's string1+string2 but with the "cde" part only once?

I'm looking for something like:

string3 = merge(string1, string2)

That would make string3 "abcdefg" and not "abcdecdefg"

I couldn't find it with google so that's why i'm asking here.

Any help would be greatly appreciated :)

Answer 1

You can check if there is an overlap first and then append only the non-overlapping parts:

# Find overlap if there is any
for i in range(1, len(string2)):
    if string1.endswith(string2[:i]):
        k = i

# Concatenate strings:
string3 = string1 + (string2 if k is None else string2[k:])

Or even simpler, set k to zero first:

# Find overlap if there is any
k = 0
for i in range(1, len(string2)):
    if string1.endswith(string2[:i]):
        k = i

# Simply concatenate them
string3 = string1 + string2[k:]

Answer 2

We can look for each occurence of the first character of s2 in s1 , and test if the rest of s1 from this occurence is the start of s2 . We need to do that from the start of s1 towards the end, in order to be sure to get the largest possible overlap.

import re

def fusion(s1, s2):
    for m in re.finditer(s2[0], s1):
        if s2.startswith(s1[m.start():]):
            return s1[:m.start()] + s2
    # no overlap found
    return s1 + s2


string1 = "abede"
string2 = "edefg" # overlap: 'ede'

print(fusion(string1, string2))
# abedefg

Answer 3

This can be simply implemented with python set() as folows..

>>> string1 = "abcde"
>>> string2 = "cdefg"
>>> string3 = string1 + string2
>>> print (''.join(sorted(set(string3))))
abcdefg

Explanation: set() removes the duplicate elements, sorted() sorts, and the join() combines it all back.