Detecting if input is int or str • Python 2.7

Question

**EDIT:***This has been solved!*

Im programming a program that will tell you if you are old enough to vote. And, when it asks you for your age, I want it to say a certain thing if the user types letters instead of a number, something like "Please enter a number, not a letter. Restart." Here is the code I have right now:

name = raw_input("What is your name?: ")
print("")
print("Hello, "+name+".\n")
print("Today we will tell you if you are old enough to vote.")
age = input("How old are you?: ")
if age >= 18:
    print("You are old enough to vote, "+name+".")
elif age < 18:
    print("Sorry, but you are not old enough to vote, "+name+".")

I suggest you to use string formatting, i.e. replace all those `'Hello, ' + name + '.'` with `'Hello, %s.' % name`. Here's a good tutorial for string formatting: https://pyformat.info/ — Markus Meskanen, May 28 '17 at 16:22

YLJ · Answer 1 · 2017-05-28T18:56:46.843

0

name = raw_input("What is your name?: ")
print("")
print("Hello, "+name+".\n")
print("Today we will tell you if you are old enough to vote.")
while True:
    age = raw_input("How old are you?: ")
    try:
        age = int(age)
    except ValueError:
        print("Please enter a number, not a letter. Restart.")
    else:
        break
if age >= 18:  
    print("You are old enough to vote, "+name+".")
elif age < 18:    # else:
    print("Sorry, but you are not old enough to vote, "+name+".")

In the try-except-else, we try to convert age from string to integer. If an ValueError occurs, it means that the input string isn't a legal integer. If not, then we can simply jump out the while loop and do the following task.

Note1: better don't use input() in python2. Refer to this.

Note2: elif is useless. Simply use else.

edited May 28 '17 at 18:56

answered May 28 '17 at 15:55

YLJ

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I can't figure out how to fit that into the code. D: – MrSprinkleToes May 28 '17 at 16:01
edited: complete the example and add some explanation. – YLJ May 28 '17 at 16:08
You probably meant `try-except-else` instead of `try-catch-else` ^^ – Markus Meskanen May 28 '17 at 16:23
@MarkusMeskanen you got me. Thanks :) – YLJ May 28 '17 at 18:56

RPT · Accepted Answer · 2017-05-28T16:05:34.457

-1

You can try something like this :

name = raw_input("What is your name?: ")
print("")
print("Hello, "+name+".\n")
print("Today we will tell you if you are old enough to vote.")
while True:
    try:
        #get the input to be an integer.
        age = int(raw_input("How old are you?: "))
        #if it is you break out of the while
        break
    except ValueError:
        print("Please enter a number, not a letter. Restart.")
if age >= 18:
    print("You are old enough to vote, "+name+".")
elif age < 18:
    print("Sorry, but you are not old enough to vote, "+name+".")

edited May 28 '17 at 16:05

answered May 28 '17 at 16:01

RPT

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I tried this, but I got an error: Traceback (most recent call last): File "vote.py", line 8, in age = int(input("How old are you?: ")) File "", line 1, in NameError: name 'Dhbe' is not defined – MrSprinkleToes May 28 '17 at 16:04
change `input` to `raw_input` – RPT May 28 '17 at 16:05

Detecting if input is int or str • Python 2.7

2 Answers2