check if a string is a number python

Question

Can I represent a string as number in python or how can I check if there is any number in string of python function.
Supose a function is:
 

def My_num(x):
      try:
             float(x)
             return True
       except ValueError:
             return False

my question is calling float in the main function is ok or not and I am not getting my expected result. 

Answer 1

If you are looking for a parsing int instead of floats you can try isdigit() function as string objects.
e.g:
 

x = "74897"
x.isdigit()
True
y = "7687wa"
y.isdigit()
False

For different approach and accurate result you can use the code:

def My_number_tryexcept(x):
    """ Returns True if string is a number. """
    try:
        float(x)
        return True
    except ValueError:
        return False

import re    
def My_number_regex(x):
    """ Returns True is string is a number. """
    if re.match("^\d+?\.\d+?$", x) is None:
        return x.isdigit()
    return True


def My_number_repl_isdigit(x):
    """ Returns True if string is a number. """
    return x.replace('.','',1).isdigit()

Try except method that handels scientific notations correctly

funcs = [
          My_number_tryexcept, 
          My_number_regex,
          My_number_repl_isdigit
          ]

x_float = '.1234'

print('Float notation ".1234" is not supported by:')
for f in funcs:
    if not f(x_float):
        print('\t -', f.__name__)

:Let me know if it is working or not.