How to stop a user from hitting enter on a Python Command Line program?

Question

Okay, so basically I'm writing an interactive Python program. Initially I will ask the user to enter their name, but even if they don't enter anything and just press enter, the program will still continue. How do I force them to hit enter?

how do you mean force them to hit enter, do you mean make sure they enter something other than an empty string? — Padraic Cunningham, Oct 02 '14 at 18:13

score 0 · Accepted Answer · answered Oct 02 '14 at 18:10

Check that the length of your variable is greater than 0.

To find the length of a string, use len(myStringVar). See the docs for more if you are curious.

To repeatedly prompt until they enter a name, you could do something like this:

user_name = ""
while len(user_name) == 0:   # While the user_name var is empty
    user_name = raw_input('Enter a user name: ')  # Prompt the user to enter a name, and assign to the user_name var

A more pythonic way of this might be:

user_name = ""
while not user_name:  # Empty strings evaluate to False
    user_name = raw_input('Enter a user name: ')

How to stop a user from hitting enter on a Python Command Line program?

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