The format code syntax {field_name:conversion}, where field_name specifies the index number of the argument to the str.format() method that we went through in the reordering section, and conversion refers to the conversion code of the data type that you’re using with the formatter. Common String Opeerations ------------------------- URL: docs.python.org/3.6/library/string.html#format-specification-mini-language Format Specification Mini-Language ---------------------------------- URL: docs.python.org/3.6/library/string.html#format-specification-mini-language