How do I check if a string is a number (float)?

Question

What is the best possible way to check if a string can be represented as a number in Python?

The function I currently have right now is:

def is_numb         


        

Answer 1

For int use this:

>>> "1221323".isdigit()
True

But for float we need some tricks ;-). Every float number has one point...

>>> "12.34".isdigit()
False
>>> "12.34".replace('.','',1).isdigit()
True
>>> "12.3.4".replace('.','',1).isdigit()
False

Also for negative numbers just add lstrip():

>>> '-12'.lstrip('-')
'12'

And now we get a universal way:

>>> '-12.34'.lstrip('-').replace('.','',1).isdigit()
True
>>> '.-234'.lstrip('-').replace('.','',1).isdigit()
False