Variables

A variable is a name that refers to a value, so you store something once and use it anywhere after that line.

Last updated: 30 Sep, 2026 · Python 3.14

In print() the ticket text was typed inside every print. A variable stores it once under a name.

print(type(1))
print(type(10.0))
print(type("Hello"))
print(type(True))

a = 10
print(type(a))
a = 'Krish Naik'
print(type(a))

<class 'int'>
<class 'float'>
<class 'str'>
<class 'bool'>
<class 'int'>
<class 'str'>

print(type(1)) shows <class 'int'> where the notebook showed int: the same type, printed in full. The same a held an int and then a string, because a Python variable takes the type of whatever it holds. The rest of this page does the same with a support ticket.

Syntax:

name = value

Storing a ticket in a variable

ticket = "My parcel has not arrived"
print(ticket)

My parcel has not arrived

= means store, not equals. The line says: put this text somewhere and call it ticket. After that, writing ticket gives you the text back.

Changing a variable

waiting = 3
print("Waiting:", waiting)

waiting = waiting + 1
print("Waiting:", waiting)

Waiting: 3
Waiting: 4

print accepts several values separated by commas and puts a space between them.

waiting = waiting + 1 looks odd as maths but reads fine as instructions. Python works out the right side first, 3 + 1, then stores the result under the name on the left.

Checking a value's type

Every value has a type, which decides what you can do with it. type tells you which one you have.

print(type("My parcel has not arrived"))
print(type(3))
print(type(4.5))
print(type(True))

<class 'str'>
<class 'int'>
<class 'float'>
<class 'bool'>

str is text, short for string. int is a whole number. float is a number with a decimal point. bool is either True or False.

Using a name that does not exist

ticket = "My parcel has not arrived"
print(tickt)

Traceback (most recent call last):
  File "main.py", line 2, in <module>
    print(tickt)
NameError: name 'tickt' is not defined. Did you mean: 'ticket'?

A typo in a name is a NameError. Python only knows the names you have stored something under, and here it even suggests the one you probably meant.

Good names vs bad names

Where variables show up in AI code

• Holding the text of a prompt before it is sent to a model.
• Keeping settings such as the model name in one place, so changing it is one line.

Related

• Previous: print()
• Next: Strings
• Reference: An Informal Introduction to Python