How to check if a string represents a float number

Question

I'm using this to check if a variable is numeric, I also want to check whether it's a floating point number.

if(width.isnumeric() == 1)

Answer 1

The easiest way is to convert the string to a float with float():

>>> float('42.666')
42.666

If it can't be converted to a float, you get a ValueError:

>>> float('Not a float')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: could not convert string to float: 'Not a float'

Using a try/except block is typically considered the best way to handle this:

try:
  width = float(width)
except ValueError:
  print('Width is not a number')

Note you can also use is_integer() on a float() to check if it's an integer:

>>> float('42.666').is_integer()
False
>>> float('42').is_integer()
True