Python Check if a variable is a number

In this Python tutorial, we will discuss Python Check if a variable is a number and also cover the below points:

  • How to check if a variable is an integer in Python
  • Check if variable is not a number in Python
  • Python check if variable is number or string
  • How to check if a variable is number or array in Python
  • Python check if variable is number or list
  • Check if variable is whole number in Python
  • Python check if variable is real number
  • How to check if variable contains a number in Python
  • Python check if variable is between two numbers

Python variable is like a memory location where to store a value. To declare a variable we just have to assign a value to it. You don’t have to give any additional commands unlike any other programming languages like C, C++, Java where you have to give an additional command for declaration and assigning purpose.

Python Check if a variable is a number

  • In this section, we will learn how to check if a variable is a number in Python.
  • We can use a method to check if a variable is a number is using a try-except block. In the try block, we can use the given variable to an int or float.

Syntax:

Here is the syntax of try-except block

try:
   print()
except:
   print()

Example

Let’s take an example to check if a variable is a number

Variable = "JOHN"
try:
    a = int(Variable)
    print('The variable a number')
except:
    print('The variable is not a number')

Here is the screenshot of following given code

Python check if a variable is a number
Python check if a variable is a number

Read: Python NumPy append + 9 Examples

How to check if a variable is an integer in Python

Suppose you have a couple of variables in a program A and B. A has an integer value while B has a decimal value so how will you check whether a is an integer or not and if b is also an integer or not.

  • In this section, we will learn how to check if a variable is an integer in Python.
  • Now the methods that we are going to use to check if the variable is an integer or not.
    • Isinstance method()
    • Try-except method()
    • Round method()

Isinstance method() is a built-in method in python which returns true when the specified object is an instance of the specified type otherwise it will return false.

Syntax:

isinstance (var,int)

Example

Let’s take an example to check if a variabe is an integer.

b = 3
c = 3.4
print(isinstance (b,int))
print(isinstance (c,int))

Here is the screenshot of following given code

Python check if a variable is an integer instance method
Python check if a variable is an integer isinstance method
  • In the Try-except block, we can use the given variable to an int or float.
  • we can use a method to check if a variable is an integer is using a try-except block.

Syntax:

Here is the syntax of try-except block

try:
   print()
except:
   print()

Example

Let’s take an example to check if a variable is an integer.

Variable = 3
try:
    a = int(Variable)
    print('Variable is integer')
except:
    print('variable is not an integer')

Here is the Screenshot of following given code

Python check if a variable is an integer try except method
Python check if a variable is an integer try except method

Round method in Python returns the nearest integer when no values are passed to the optional digit argument.

Syntax:

Here is the syntax of Round method

round(number,number of digits)

Example

Let’s take an example to check if a variable is an integer

def is_int(value):
   if value == round(value):
     print("True")
   else:
     print("False")

c=4
d=4.5
is_int(c)
is_int(d)

Here is the screenshot of following given code

Python check if a variable is an integer round method
Python check if a variable is an integer round method

Read: How to create a variable in python

Python check if a variable is not a number

  • In this section, we will learn how to check if a variable is not a number in Python.
  • we can use a try-except method to check if a variable is not a number is using a try-except block. In the try block, we can use the given variable to an int or float.

Syntax:

Here is the syntax of try-except block

try:
   print()
except:
   print()

Example

Let’s take an example to check if a variable is not a number

Variable = "Micheal"
try:
    a = int(Variable)
    print('Variable is a number')
except:
    print('variable is not a number')

Here is the screenshot of following given code

Python check if a variable is not a number
Python check if a variable is not a number

Python check if variable is number or string

  • In this section, we will learn how to check if a variable is a number or string in Python.
  • We can easily use an isinstance method to check if a variable is a number or string is using an isinstance() method.
  • Isinstance method() is a built-in method in python which returns true when the specified object is an instance of the specified type otherwise it will return false.

Syntax:

isinstance (var,int)

Example

Let’s take an example to check if a variable is number or string

Variable = "Micheal"
try:
    a = int(Variable)
    print('The variable a number')
except:
    print(' variable is string')
    print(isinstance (Variable,str))

Here is the Screenshot of following given code

Python check if variable is number or string
Python check if variable is number or string

This is how to check if variable is number or string in Python.

Read: How to split a string using regex in python

Python check if variable is number or array

  • In this section, we will learn how to check if a variable is a number or array in Python.
  • we can use a try-except method to check if a variable is a number or array is using a try-except block. In the try block, we can use the given variable to an int or float.

Syntax:

Here is the syntax of try-except block

try:
   print()
except:
   print()

Example

Let’s take an example to check if a variable is a number or array

import numpy as np

Variable = ([1,2,3])
try:
    a = int(Variable)
    print(' variable is number')
except:
    print(' variable is array')

Here is the Screenshot of following given code

Python check if variable is number or array
Python check if variable is number or array

This is how to check if variable is number or array in Python.

Read Python Dictionary update with examples

Python check if variable is number or list

  • In this section, we will learn how to check if a variable is a number or a list in Python.
  • we can use a try-except method to check if a variable is a number or a list is using a try-except block. In the try block, we can use the given variable to an int or float.

Syntax:

Here is the syntax of try-except block

Example

Let’s take an example to check if a variable is a number or list


Var = [1,2,3,4,"John"]
try:
    a = int(Var)
    print(' variable is number')
except:
    print(' variable is a list')
    

Here is the Screenshot of following given code

Python check if variable is number or list
Python check if variable is number or list

This is how to check if variable is number or list in Python.

Read: Check if a list is empty in Python

Python check if a variable is a whole number

  • In this section, we will learn how to check if a variable is a whole number in Python.
  • Now the methods that we are going to use to check if the variable is a whole number.
    • int() method
    • try-except method

int() function is a built up function that will convert any string or float to into a integer form.

Syntax:

Here is the syntax of int() method

int(String,base)

Example

Let’s take an example to check if variable is whole number.

y = 3.2
print(y - int(y) == 0)
# true if y is a whole number
# false if it is decimal number

Here is the Screenshot of following given code.

Python Check if variable is whole number
Python check if variable is whole number
  • Now another method is the Try-except block, we can use the given variable to an int or float.
  • we can use this method to check if a variable is a whole number by using a try-except block.

Syntax:

Here is the syntax of try-except block

try:
   print()
except:
   print()

Example

Let’s take an example to check if variable is whole number.

Var = 4
try:
    a = int(Var)
    print(' variable is whole number')
except:
    print(' variable is not a whole number')
    

Here is the screenshot of following given code.

Python check if variable is whole number try except method
Python check if variable is whole number try except method

Python check if variable is real number

  • Any number that can be plotted on a number line is called a real number in Python.
  • In this section, we will learn how to check if a variable is a real number or not.
  • we can use a try-except method to check if a variable is a number or a list is using a try-except block. In the try block, we can use the given variable to an int or float.

Syntax:

try:
   print()
except:
   print()

Example

Let’s take an example to check if variable is real number or not.

Var = 4.333
try:
    a = int(Var)
    print(' variable is a real number')
except:
    print(' variable is not a whole number')

Here is the Screenshot of following given code.

Python check if a variable is a real number
Python check if a variable is a real number

This is how to check if variable is real number in Python.

Read: How to convert list to string in Python

Python check if variable is between two numbers

  • In this section, we will learn how to check if a variable is between two numbers in Python.
  • Create a range of integers from start to end. Use keyword integers to check if a variable is between two numbers.

Syntax:

range(start,stop)

Example

Let’s take an example to check if variable is between two numbers.

Var = 9
is_between = 9 in range(6, 18)
#Check if 9 lies between 6 and 18

print(is_between)

Here is the Screenshot of following given code.

Python check if variable is between two numbers
Python check if variable is between two numbers

This is how to check if variable is between two numbers in Python.

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In this Python tutorial, we learned how to check if a variable is a number in Python and the below examples:

  1. Python Check if a variable is a number
  2. Python check if a variable is an integer
  3. Python check if a variable is not a number
  4. Python check if a variable is number or string
  5. Python check if a variable is number or array
  6. Python check if a variable is number or list
  7. Python check if a variable is whole number
  8. Python check if a variable is real number
  9. Python check if a variable is between two numbers