Creating Variables

Creating Variables

Unlike other programming languages, Python has no command for declaring a variable.

A variable is when you assign a value to the variable.

Example

a = 555

b = "sateesh"

c = 1.314

d = 'm'

print(a)

print(b)

print(c)

print(d)

output:-

555

sateesh

1.314

m

Variables do not need to be declared with any particular type and can even change type after they have been set.

Example

a = 555   # a is of type int

b = "sateesh" # a is now of type str

print(x)

output:-

sateesh

Variable Names

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

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

Output Variables

The Python print statement is often used to output variables.

To combine both text and a variable, Python uses the + character:

Example

x = "awesome"
print("Python is " + x)

Python is awesome

You can also use the + character to add a variable to another variable:

Example

x = "Python is "
y = "awesome"
z =  x + y
print(z)

Python is awesome

For numbers, the + character works as a mathematical operator:

Example

x = 777
y = 76
print(x + y)

853

If you try to combine a string and a number, It is not valid in Python. Python will give you an error:

Example

x = 5
y = "John"
print(x + y)

TypeError: unsupported operand type(s) for +: 'int' and 'str'