Python Variable Names

Variable Names in Python

When naming your variables, you need to follow a few rules:

1. A variable name must start with a letter or the underscore (_) character.
2. It cannot start with a number.
3. Variable names can only contain letters, numbers, and underscores (A-z, 0-9, and _).
4. Variable names are case-sensitive (age, Age, and AGE are different variables).

Legal variable names:

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myvar = "Smith"
_my_var = "Smith"
myVar2 = "Smith"

Illegal variable names:

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2myvar = "Smith"  # Cannot start with a number
my-var = "Smith"  # Hyphens are not allowed
my 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:

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a = 4
A = "Sally"
# 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.

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myVariableName = "Smith"

• Pascal Case: Every word starts with a capital letter.

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MyVariableName = "Smith"

• Snake Case: Each word is separated by an underscore.

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my_variable_name = "Smith"

Assigning Multiple Values to Variables

Python allows you to assign values to multiple variables at once.

Example:

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x, y, z = "Orange", "Grapes", "Cherry"
print(x)
print(y)
print(z)

Assigning One Value to Multiple Variables

You can assign the same value to multiple variables in one line.

Example:

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x = y = z = "Orange"
print(x)
print(y)
print(z)

Unpacking a Collection

If you have a collection (like a list or tuple), you can unpack its values into variables.

Example:

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fruits = ["Orange", "Grapes", "Cherry"]
x, y, z = fruits
print(x)
print(y)
print(z)