dicts

A python dict is a keymap, with some of the important features being:

• a dict is mutable

• dict keys MUST be immutable such as a str, int, float, or tuple

• dict values may be any object type, including list, tuple, int, str or even another dict

• a dict is iterable

• the access time for a dict is very fast, regardless of the size of the dict.  In BigO notation, the time complexity to access a value with a given key is O(1).  Learn about BigO notation.

Passing dicts to functions

Just as with a list - another mutable object - passing a dict to a function will pass by reference, not by value. This means that when a function receives a dict object, any changes made to that dict inside the function are made to the dict in global space. Because of this, if you make changes to a dict object inside a function, there is no need to return the mutated dict, as the changes are made to the actual dict.

A Practical example

We have used helper functions such as title_gen, menu_gen, get_int and so on.

The following video details a way to build a shopping basket.

Re-write this application using the helper functions we have used before, with the end result being the following: