2.8 Programming Page 8

Variables:

Python offers special “boxes” (containers) to store data called variables. The name suggests that the content of these containers can be varied in (almost) any way.

• a name
  
  
• a value (the content of the container)

 

Rules for naming variables:

• The name of the variable must be composed of upper-case or lower-case letters, digits, and the character underscore (underscore).
  
  
• The name of the variable must begin with a letter.
  
  
• The underscore character is a letter.
  
  
• Upper- and lower-case letters are treated as different (This is a little different than in usual writing where Alice and ALICE are the same first names. In Python, they are two different variable names, and consequently, two different variables.
  
  
• The name of the variable must not be any of Python’s reserved words , such as print. (These are keywords, which will be explained more soon).

 Keywords that should not be used as variable names:

Python does not impose restrictions on the length of variable names, but a short variable name is preferred to a long one. Short, clear and descriptive is always best!