Check if a given string is numeric in Python

This post will discuss how to check if a string is numeric in Python.

1. Using `float()` function

The idea is to convert the string to a float and return false if the conversion is not possible. This can be easily done using the float(x) function, which converts the string x into a floating-point number and raises the ValueError when it cannot convert x into a valid float.

def isNumeric(s):

try:

float(s)

return True

except ValueError:

return False

if __name__ == '__main__':

s = "100"

print(isNumeric(s)) # True

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Note that the float(x) function accepts a NaN (not-a-number) or a positive or negative infinity as the string argument.

2. Using `complex()` function

Alternatively, you can use the complex() function to convert a string to a complex number. Like the float() function, it accepts a NaN (not-a-number) or a positive or negative infinity as the string argument and returns True.

def isNumeric(s):

try:

complex(s)

return True

except ValueError:

return False

if __name__ == '__main__':

s = "100"

print(isNumeric(s)) # True

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3. Using `isdigit()` function

Another option is to use the str.isdigit() function, which returns True when the given string is a positive integer. However, it returns False when the string is a float number or a negative number.

def isNumeric(s):

return s.isdigit()

if __name__ == '__main__':

s = "100"

print(isNumeric(s)) # True

Download Run Code

That’s all about determining whether a given string is numeric in Python.

Check if a given string is numeric in Python

1. Using float() function

2. Using complex() function

3. Using isdigit() function

Share this:

1. Using `float()` function

2. Using `complex()` function

3. Using `isdigit()` function