longest common prefix with comments

Longest Common Prefix.py

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+class Solution:
+    def longestCommonPrefix(self, strs: List[str]) -> str:
+        # compares first letter of all words, then moves to next letter
+        s = ""
+        if len(strs)==0: #edge case, no elements in list
+            return s
+        elif len(strs)==1: #edge case, single element in list
+            return strs[0]
+
+        #word length of shortest word to prevent index out of range
+        for a in range(len(min(strs))): 
+            #loops through each word in list, starting with second word
+            for b in range(1, len(strs)): 
+                #compares nth character of first word to other words
+                if strs[0][a]==strs[b][a]: 
+                    #only adds to pattern if nth character same up to the last word
+                    if b==len(strs)-1: 
+                        s += strs[0][a]
+                else: #exits when characters don't match
+                    return s
+        return s