Added isogram implementation

Author: OmkarPathak

pygorithm/string/isogram.py

@@ -0,0 +1,25 @@
+# Author: OMKAR PATHAK
+# Created On: 17th August 2017
+
+def is_isogram(word):
+    '''
+        An isogram (also known as a "nonpattern word") is a logological term for a word
+        or phrase without a repeating letter
+    '''
+    # Convert the word or sentence in lower case letters.
+    clean_word = word.lower()
+    # Make ann empty list to append unique letters
+    letter_list = []
+    for letter in clean_word:
+        # If letter is an alphabet then only check
+        if letter.isalpha():
+            if letter in letter_list:
+                return False
+            letter_list.append(letter)
+
+    return True
+
+def get_code():
+    """ returns the code for the current class """
+    import inspect
+    return inspect.getsource(is_isogram)