1.2. check permutation pythonic changes

use of counter and *strings for tuples

Chapter 1 Arrays and strings/1.2. check_permutation.py

@@ -1,10 +1,12 @@
 import unittest
+from time import time
+from collections import Counter
 
 def check_permutation(s1, s2):
     if len(s1) != len(s2):
         return False
-    checker = dict()
 
+    checker = dict()
     for char in s1:
         ascii_val = ord(char)
         if ascii_val not in checker:
@@ -17,29 +19,52 @@ def check_permutation(s1, s2):
         if ascii_val not in checker:
             return False
         checker[ascii_val] -= 1
-        if checker[ascii_val] == 0:
-            del checker[ascii_val]
         if checker[ascii_val] < 0:
             return False
-    if checker == {}:
     return True
-    else:
+
+def check_permutation_pythonic(s1, s2):
+    if len(s1) != len(s2):
         return False
+    if len(s1) <= 1:
+        return True
+
+    counter = Counter()
+    for char in s1:
+        counter[char] += 1
+    for char in s2:
+        if counter[char] == 0:
+            return False
+        counter[char] -= 1
+    return True
 
 class Test(unittest.TestCase):
-    dataT = [('abcd', 'dbca'), ('dfgh', 'dfgh'), ('', '')]
+    dataT = [('abcd', 'dbca'), ('dfgh', 'dhgf'), ('', '')]
     dataF = [('aane', 'anee'), ('ab', 'ca'), ('ane', 'aane')]
 
     def test(self):
         # true check
         for test_string in self.dataT:
-            s1, s2 = test_string
-            res = check_permutation(s1, s2)
+            start = time()
+            res = check_permutation(*test_string)
             self.assertTrue(res)
+            print(f"{time() - start}s")
+
+            start = time()
+            res = check_permutation_pythonic(*test_string)
+            self.assertTrue(res)
+            print(f"{time() - start}s")
+
         # false check
         for test_string in self.dataF:
-            s1, s2 = test_string
-            res = check_permutation(s1, s2)
+            start = time()
+            res = check_permutation(*test_string)
+            self.assertFalse(res)
+            print(f"{time() - start}s")
+
+            start = time()
+            res = check_permutation_pythonic(*test_string)
+            print(f"{time() - start}s")
             self.assertFalse(res)
 
 if __name__ == "__main__":