Assignment 1 commit: Moon & Apollo

util/tools.py

@@ -0,0 +1,21 @@
+def substring(string: str, start: int, end: int = 0) -> str:
+    """
+    A substring function
+    :param string: The string
+    :param start: The starting index
+    :param end: The ending index. If None, this is set to the length of the substring     :return:
+    """
+    if not isinstance(string, str):
+        raise ValueError("No string provided")
+    if not isinstance(start, int):
+        raise ValueError("No starting index provided")
+
+    if end is None:
+        end = len(str)
+
+    result = ""
+
+    for i in range(start, end):
+        result += string[i]
+
+    return result