Python: Check whether a given string is number or not using Lambda

Last update on April 22 2025 12:55:55 (UTC/GMT +8 hours)

9. String Number Checker Lambda

Write a Python program to check whether a given string is a number or not using Lambda.

Sample Solution:

Python Code :

# Define a lambda function 'is_num' that checks if a given string 'q' represents a number:
# It first removes the first decimal point in the string using 'replace()',
# then checks if the resulting string is composed of digits using 'isdigit()'
is_num = lambda q: q.replace('.', '', 1).isdigit()

# Check if the given strings are numeric by using the 'is_num' lambda function and print the results
print(is_num('26587'))
print(is_num('4.2365'))
print(is_num('-12547'))
print(is_num('00'))
print(is_num('A001'))
print(is_num('001'))

# Print a line break to separate the previous output from the next set of results
print("\nPrint checking numbers:")

# Define a lambda function 'is_num1' that further checks if a string represents a number by
# excluding a minus sign at the beginning if present and then using the 'is_num' lambda function
# This function calls 'is_num' on the string without the leading '-' if the string starts with '-'
is_num1 = lambda r: is_num(r[1:]) if r[0] == '-' else is_num(r)

# Check if the given strings (with a possible leading '-') are numeric using 'is_num1' lambda function and print the results
print(is_num1('-16.4'))
print(is_num1('-24587.11'))

Sample Output:

True
True
False
True
False
True

Print checking numbers:
True
True

For more Practice: Solve these Related Problems:

Write a Python program to check if a given string represents a valid floating-point number using lambda.
Write a Python program to determine if a given string is a valid hexadecimal number using lambda.
Write a Python program to validate whether a given string is a valid integer, including negatives, using lambda.
Write a Python program to check if a given string represents a complex number using lambda.

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Python Code Editor:

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