How to store the output of type function in python and use it in 'if' condition?

Question

How can we store the output of 'type' function in a variable ?

next = raw_input('> ')
type = type(next)

if type == 'int':
   val = int(next)
else:
   print "Type a number!"

Syntax Error at line 4....?

You can't use `type` that way - it will always be `str` because thats what raw_input returns. You could use just `input` — muddyfish, Aug 23 '16 at 13:06
@muddyfish just realized that and updated my answer. I wonder why they removed that in python 3 :) — Jean-François Fabre, Aug 23 '16 at 13:20
You may find this helpful: http://stackoverflow.com/questions/23294658/asking-the-user-for-input-until-they-give-a-valid-response — PM 2Ring, Aug 23 '16 at 13:28
BTW, overwriting the built-in functions [`next`](https://docs.python.org/2.7/library/functions.html#next) and [`type`](https://docs.python.org/2.7/library/functions.html#type) is a very very bad idea. — Matthias, Aug 23 '16 at 15:47
Well.., I figured out that I just can't use "type" as a name for any variable because it is an inbuilt python keyword. — Shash Aeon, Aug 07 '21 at 12:35

Jean-François Fabre · Accepted Answer · 2016-08-23T13:16:48.680

There are several ways of doing what you want. Note that defining a type variable to mask the type function is not good practice! (and next either BTW :))

n = raw_input('> ')  # (or input in python 3)

try: 
   val = int(n)
except ValueError:
   print("Type a number!")

or

n = raw_input('> ')  # (or input in python 3)

if n.isdigit():
   val = int(n)
else:
   print("Type a number!")

Note: as some comment indicated, that in python 2, it was possible to get what you wanted by just using

n = input("> ")

but very ill adviced since you have to control what n is really, not python 3 portable, and has huge security issues:

Ex: in python 2 on windows, try that:

import os
n = input("> ")

and type os.system("notepad")

you'll get a nice notepad windows !! You see that it is really not recommended to use input (imagine I type os.system("del <root of your system>")) ...

`int("3.5")` throws `ValueError` too. but `isdigit` is singular!! fixed! — Jean-François Fabre, Aug 23 '16 at 13:18

How to store the output of type function in python and use it in 'if' condition?

1 Answers1