Python check if string is float

You can use isdigit() + replace() or float() + Exception handling to check if a string is a float in Python. Using the float function try to convert the string to a floating point value, and if it’s failed that it’s not a potential float value.

Python checks if the string is a float example

Simple example code.

s = "10.657"

# using isdigit() + replace()
res = s.replace('.', '', 1).isdigit()
print(res)

# using float()
try:
    float(s)
    res = True
except:
    print("Not a float")
    res = False

print(res)

Output:

Using regular expression to check if the string is a valid float

import re

def is_float(string):
    pattern = r"^[-+]?[0-9]*\.?[0-9]+$"
    match = re.match(pattern, string)
    return bool(match)

s = "10.657"
print(is_float(s))

Checking to see if a string is an integer or float

If the string is convertible to an integer, it should be digits only.

if NumberString.isdigit():
    Number = int(NumberString)
else:
    Number = float(NumberString)

If you already have Number confirmed as a float, you can always use is_integer (works with negatives):

if Number.is_integer():
    Number = int(Number)

Do comment if you have any doubts or suggestions on this Python string topic.

Note: IDE: PyCharm 2021.3.3 (Community Edition)

Windows 10

Python 3.10.1

All Python Examples are in Python 3, so Maybe its different from python 2 or upgraded versions.