added susbstring code for python

substring.py

@@ -0,0 +1,17 @@
+# Python3 code to demonstrate working of
+# Get all substrings of string
+# Using list comprehension + string slicing
+
+# initializing string
+test_str = "Geeks"
+
+# printing original string
+print("The original string is : " + str(test_str))
+
+# Get all substrings of string
+# Using list comprehension + string slicing
+res = [test_str[i: j] for i in range(len(test_str))
+		for j in range(i + 1, len(test_str) + 1)]
+
+# printing result
+print("All substrings of string are : " + str(res))