Python Variable Names
Variable Names in Python
When naming your variables, you need to follow a few rules:
- A variable name must start with a letter or the underscore (
_
) character. - It cannot start with a number.
- Variable names can only contain letters, numbers, and underscores (A-z, 0-9, and
_
). - Variable names are case-sensitive (
age
,Age
, andAGE
are different variables).
Legal variable names:
python
1myvar = "Smith"
2_my_var = "Smith"
3myVar2 = "Smith"
Illegal variable names:
python
12myvar = "Smith" # Cannot start with a number
2my-var = "Smith" # Hyphens are not allowed
3my var = "Smith" # Spaces are not allowed
Python Case Sensitive
Variable names in Python are case-sensitive. This means that myVar
, MyVar
, and myvar
are all different variables.
Example:
python
1a = 4
2A = "Sally"
3# Here, a and A are two different variables
Python Multi-Word Variable Names
If your variable name has more than one word, there are a few common styles for writing it:
- Camel Case: Each word except the first starts with a capital letter.
python
1myVariableName = "Smith"
- Pascal Case: Every word starts with a capital letter.
python
1MyVariableName = "Smith"
- Snake Case: Each word is separated by an underscore.
python
1my_variable_name = "Smith"
Assigning Multiple Values to Variables
Python allows you to assign values to multiple variables at once.
Example:
python
1x, y, z = "Orange", "Grapes", "Cherry"
2print(x)
3print(y)
4print(z)
Assigning One Value to Multiple Variables
You can assign the same value to multiple variables in one line.
Example:
python
1x = y = z = "Orange"
2print(x)
3print(y)
4print(z)
Unpacking a Collection
If you have a collection (like a list or tuple), you can unpack its values into variables.
Example:
python
1fruits = ["Orange", "Grapes", "Cherry"]
2x, y, z = fruits
3print(x)
4print(y)
5print(z)