Python code to be executed multiple times the result is different? Why-CodePudding

This problem is to seek the longest prefix

 
Def longestCommonPrefix (STRS) : 
STRS=list (set (STRS)) 
Lenth=len (STRS) 
If the STRS!=[] : 
Pub_str="" 
If STRS [0]=="" : 
Return "" 
Elif lenth==1 and STRS [0]!="" : 
Return STRS [0] 
For I in STRS [0] : 
Pub_str +=I 
Print (pub_str) 
For j in (1, lenth - 1) : 
If len (pub_str) & gt; Len (STRS) [j] or not STRS [j]. J startswith (pub_str) : 
Return pub_str] [: - 1 
The else: 
The continue 
The else: 
Return "" 
The STRS=[" aa ", "a"] 
The index=longestCommonPrefix (STRS) 
Print (index)

Why the above code execution result different for many times, from time to time is to None for a, is in don't understand

CodePudding user response:

Debug the view variable flow can be clear at a glance,