urlify

Author: miguelHx

Python/chapter01/1.3 - URLify/miguel_1.3_sol.py

@@ -0,0 +1,52 @@
+"""
+Python version 3.7.0
+1.3 - URLify
+Write a method to replace all spaces in a string with "%20".  You may assume that the string has sufficient
+space at the end to hold the additional characters, and that you are given the "true" length of the string.
+(Note: If implementing in Java, please use a character array so that you can perform this operation in place)
+"""
+import unittest
+from typing import Callable
+
+
+def urlify(s: str, true_length: int) -> str:
+    """
+    Given a string and it's "true" length, this function will return a new string
+    that replaces all of the spaces of the input string with '%20'.
+    Precondition(s):
+    - length of s <= true_length
+    :param s: the original string to 'urlify'
+    :param true_length: since s may have additional characters, we focus on true_length instead of actual s length
+    :return: string with each space from s replaced with '%20'
+    """
+    output = ""
+    for i, c in enumerate(s):
+        if i == true_length:
+            break
+        if c == ' ':
+            output += "%20"
+            continue
+        output += c
+    return output
+
+
+class TestUrlifyFunction(unittest.TestCase):
+    def _run_tests(self, f: Callable[[str, int], str]) -> None:
+        cases = [
+            ("Mr John Smith     ", 13, "Mr%20John%20Smith"),
+            ("Miguel Hernandez", 16, "Miguel%20Hernandez"),
+            (" Techqueria ", 11, "%20Techqueria"),
+            ("a b c d e f g h", 15, "a%20b%20c%20d%20e%20f%20g%20h"),
+            ("a b c d e f g h ignore this", 15, "a%20b%20c%20d%20e%20f%20g%20h"),
+            ("ihavenospaces", 13, "ihavenospaces"),
+            ("nospacesIgnoreme", 8, "nospaces")
+        ]
+        for case in cases:
+            self.assertEqual(f(case[0], case[1]), case[2], msg=case)
+
+    def test_urlify(self):
+        self._run_tests(urlify)
+
+
+if __name__ == '__main__':
+    unittest.main()