Reducing a list of strings to known signature strings

Question

I have a list consisting of string signatures:

lis1 = {"ab","cd","ef","gh"}

I have another list:

lis2 = {"ab","efij","cde"}

I would like to find elements in lis2 that begin with known signatures in lis1 and then replace them with the corresponding signatures from lis1 to get:

res = {"ab", "ef", "cd"}

Hopefully, this is clearly stated. Please let me know if it isn't.

Answer 1

There might be some edge cases to consider, but you might approach it as follows. Create a replacement rule for each element of lis1 (and keep a list of such rules):

replaceRules = (# ~~ ___ -> #) & /@ lis1

Now use this list of rules in StringReplace:

StringReplace[lis2, replaceRules]

Answer 2

Using SubsetQ:

StringJoin @@@ 
 First /@ Select[Tuples[{Characters[lis1], Characters[lis2]}]
   , SubsetQ[Last@#, First@#] &]

{"ab", "cd", "ef"}