4.1 Variable Names

By | September 29, 2021

Variable Names

A variable can have a short name (like x and y) or a more descriptive name (age, car name, total_volume). Rules for Python variables:

  • A variable name must start with a letter or the underscore character
  • A variable name cannot start with a number
  • A variable name can only contain alpha-numeric characters and underscores (A-z, 0-9, and _ )
  • Variable names are case-sensitive (age, Age and AGE are three different variables)

Example

Legal variable names:myvar = “John”
my_var = “John”
_my_var = “John”
myVar = “John”
MYVAR = “John”
myvar2 = “John”

Output:

John
John
John
John
John
John

Example

Illegal variable names:

Example

Illegal variable names:

2myvar = “John”
my-var = “John”
my var = “John”
#This example will produce an error in the result

Multi Words Variable Names

Variable names with more than one word can be difficult to read.

There are several techniques you can use to make them more readable:

Camel Case

Each word, except the first, starts with a capital letter:

myVariableName = “John”

Pascal Case

Each word starts with a capital letter:

MyVariableName = “John”

Snake Case

Each word is separated by an underscore character:

my_variable_name = “John”

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