Python: Check whether a string is numeric

Last update on April 16 2025 13:06:58 (UTC/GMT +8 hours)

Check if String is Numeric

Write a Python program to check whether a string is numeric.

Sample Solution-1:

Python Code:

# Define a string named str containing the value 'a123'.
str = 'a123'

# Uncomment the line below to test a different string (e.g., '123').
# str = '123'

# Try to convert the string str to a float.
try:
    i = float(str)
except (ValueError, TypeError):
    # If a ValueError or TypeError occurs during conversion, print 'Not numeric.'
    print('\nNot numeric')

# Print a newline character to format the output.
print()

Sample Output:

Not numeric

Flowchart:

Sample Solution-2:

Python Code:

# Doesn't work for floats
# Prompt the user for input and store it in the 'text' variable.
text = input("Input a word or numbers: ")

# Check if the input consists of digits only using the 'isdigit' method.
if text.isdigit():
    # If the input contains only digits, print "The input value is numbers."
    print("The input value is numbers.")
else:
    # If the input contains characters other than digits, print "The input value is string."
    print("The input value is string.")

Sample Output:

Input a word or numbers:  a123
The input value is string.

For more Practice: Solve these Related Problems:

Write a Python program to check if a string contains only floating-point numbers.
Write a Python program to validate whether a string represents a valid integer without using `isdigit()`.
Write a Python program to extract all numeric values from a mixed alphanumeric string.
Write a Python program to determine if a string is a valid representation of a hexadecimal number.

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