Variables

Variables are stored with assignment statements.

An assignment statement consists of a variable name and an assignment operator (equal sign).

spam = 42

Variables are initialized the first time a value is stored in it. When a variable is assigned a new value the old value is overwritten.

>>> eggs = 'red'
>>> eggs
'red'
>>> eggs = 'green'
>>> eggs
'green'

Variable Names #

A good variable name describes the data it contains.

Variable names must follow these three rules:

  • One word no spaces
  • Only use letters, numbers and the _ character.
  • Can’t begin with a number

Variables are case sensitive. It’s python convention to start your variables lowercase.

Use either camelCase or underscore_variables. PEP 8 specifies underscores, but consistency is more important than which style you choose.

A foolish consistency is the hobgoblin of little minds

Variables and References #

Variables store a reference to the data not the actual data itself. References can be copied to other variables with things like

spam = ['eggs', 42, 'bacon']
cheese = spam

See: references