Python | Check if the given string is numeric or not

Python Methods and Functions | Regular Expressions | String Variables

Examples :

  Input:  28  Output:  digit  Input:  a  Output:  not a digit.  Input:  21ab  Output:  not a digit. 

Code # 1: Using Python Regular Expressions

re.search (): This method either returns None (if the pattern does not match), or re.MatchObject, which contains information about the corresponding part of the string. This method stops after the first match, so it's better for checking regular expressions than for extracting data.

# Python program for identifying a digit

 
# import re module

 
# re module provides support
# for regular expressions

import re

 
# Make a regular expression
# to identify a digit

regex = '^ [0-9] + $'

 
# Define a function for
# digit identification

def check (string): 

 

# pass regex

# and a line in the search () method

  if (re.search (regex, string)): 

print ( "Digit"

 

else

prin t ( "Not a Digit"

 

 
Driver code

if __ name__ = = '__main__'

 

# Enter a string

string = " 28 "

  

  # call the run function

check (string)

  

  string = "a"

check (string)

 

string = "21ab"

check (string)

 

string = "12ab12"

check (string)

Exit :

 Digit Not a Digit Not a Digit Not a Digit 

Code # 2: Using the string.isnumeric ()

# Python code to check is whether the string is numeric or not

 
# checking numeric characters

string = '123ayu456'

print (string.isnumeric ()) 

 

string = ' 123456'

print (string.isnumeric ()) 

Exit:

 False True 




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