python – Default values on empty user input

python – Default values on empty user input

Python 3:

input = int(input(Enter the inputs : ) or 42)

Python 2:

input = int(raw_input(Enter the inputs : ) or 42)

How does it work?

If nothing was entered then input/raw_input returns empty string. Empty string in Python is False, bool() -> False. Operator or returns first truthy value, which in this case is 42.

This is not sophisticated input validation, because user can enter anything, e.g. ten space symbols, which then would be True.

You can do it like this:

>>> try:
        input= int(raw_input(Enter the inputs : ))
    except ValueError:
        input = 0

Enter the inputs : 
>>> input
0
>>> 

python – Default values on empty user input

One way is:

default = 0.025
input = raw_input(Enter the inputs : )
if not input:
   input = default

Another way can be:

input = raw_input(Number: ) or 0.025

Same applies for Python 3, but using input():

ip = input(Ip Address: ) or 127.0.0.1