Added indexed placeholders sample

examples/string_format.py

@@ -1,4 +1,4 @@
-# Basic placeholders
+# Basic placeholders usage
 
 ingredient = "sugar"
 quantity = "500g"
@@ -8,7 +8,24 @@ ingredient_string = "- {}: {}".format(ingredient, quantity)
 print(ingredient_string)
 
 
-# Named placeholders
+
+
+# Indexed placeholders usage
+#
+#   Placeholders are identified by index number, 0 being the first parameter passed
+
+
+name = "John"
+age = 30
+
+greetings = "My name is {0}, i'm {1}.".format(name, age) 
+
+
+
+
+# Named placeholders usage
+#
+#   Placeholders are identified by name, order doesn't matter
 
 fname = "John"
 lname = "Doe"
@@ -16,3 +33,8 @@ lname = "Doe"
 bond_string = "My name is {lastname}, {firstname} {lastname}".format(firstname=fname, lastname=lname)
 
 print(bond_string)
+
+
+
+
+