working string compressions

Author: nimbusscale

algorithms/string_compression.py

@@ -0,0 +1,46 @@
+#!/usr/bin/env python3
+"""Python solution for CtCI 6th Edition Problem 1.4
+
+Implement a method to perform basic string compression using the counts of
+repeated characters. For example, the string aabcccccaaa would become a2b1c5a3.
+If the "compressed" string would not become smaller than the original string,
+your method should return the original string. You can assume the string has
+only uppercase and lowercase letters (a - z).
+
+>>> compress_string("aabcccccaaa")
+'a2b1c5a3'
+
+>>> compress_string('aaaaaaaa')
+'a8'
+
+Following examples would return strings that are shorter than or equal to the
+original string and just return the original string.
+>>> compress_string("aabbccaa")
+'aabbccaa'
+
+>>> compress_string("aabcca")
+'aabcca'
+
+>>> compress_string("abcde")
+'abcde'
+"""
+
+
+def compress_string(string):
+    char_count = 1
+    compressed_string = ""
+    for pos, char in enumerate(string):
+        if pos + 1 < len(string) and char == string[pos + 1]:
+            char_count += 1
+        else:
+            compressed_chars = char + str(char_count)
+            compressed_string = compressed_string + compressed_chars
+            char_count = 1
+    if len(compressed_string) < len(string):
+        return compressed_string
+    else:
+        return string
+
+if __name__ == "__main__":
+    input_string = input("Enter string to compress: ")
+    print(compress_string(input_string))