isnumeric (checking if string is numeric) Implementation?

[kat-rng]

I am reading the output from a matrix keyboard library and am trying to check if the output (returned as a character from the library used) can be converted to a number. I saw that isalpha is implemented, but since the keypad can return "#" I am curious, is there is any equivalent to isnumeric implemented? And if not, is using a try except to get this behavior (as shown below) inadvisable? Thanks!

def isnumeric(string):
    try: 
        float(string)
    except ValueError:
        return False
    return True

[2dof]

You can check multiple instances with isinstance()

value = '#'
if  isinstance(value,(float,int)): 
      print('is nmeric')
else:
     print('not nmeric')

[rkompass]

@kat-rng The try/except is appropriate. You have to consider that issue.
So you could also check if the characters of the string are in '+-.eE0123456789'. This excludes something like '1_000e3' but that should be no problem.

[kat-rng]

Thank you. I was a little worried that running trys and excepts constantly may cause problems, but I take it that it's fine.

[jimmo]

@2dof this code does not actually do the thing that @kat-rng was asking for (namely to check if a string contains only the characters 0-9).

e.g.

>>> value = '#'
>>> isinstance(value,(float,int))
False
>>> value = '22'
>>> isinstance(value,(float,int))
False          <--- should be true

There are lots of ways to solve this particular problem... @kat-rng your solution with float() doesn't technically match CPython's implementation of str.isnumeric which is defined as "A string is numeric if all characters in the string are numeric and there is at least one character in the string."

Here is a simple version that doesn't involve try/except.

return bool(value and not value.strip("0123456789"))

[rkompass]

Thats one of many nice things: It becomes like if, else.--Diese Nachricht wurde von meinem Android Mobiltelefon mit GMX Mail gesendet.Am 16.06.23, 21:20 schrieb kat-rng ***@***.***>: Thank you. I was a little worried that running trys and accepts constantly may cause problems, but I take it that it's fine. —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you commented.Message ID: ***@***.***>