How to run a while loop as long as there is no error

Question

I am running a code that might get an error, but I want to run it as long as there is no error.

I thought about something like that:

while ValueError:
    try:
        x = int(input("Write a number: "))
    except ValueError:
        x = int(input("You must write a number: "))`

@BhargavRao no [tag:python] in the initial revision (or no gold badge in [tag:python-3.x], depending on how you look at it!) — jonrsharpe, Apr 21 '15 at 18:08

Bhargav Rao · Accepted Answer · 2015-04-21T17:58:50.370

5

You were quite near

while True:
    try:
        x = int(input("Write a number: "))
        break
    except ValueError:
        print("You must write a number: ")

To know more about exception handling, refer the documentation

edited Apr 21 '15 at 17:58

answered Apr 21 '15 at 17:55

Bhargav Rao

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Thanks for that @Padraic ... Used to not using brains! – Bhargav Rao Apr 21 '15 at 17:59
What about an `else` block? – Zizouz212 Apr 21 '15 at 18:16
@Zizouz212 That's more *Pythonic*, this is more *intuitive*. You can choose whatever you like! :) – Bhargav Rao Apr 21 '15 at 18:17
1

I'll post an answer mentioning it. :) – Zizouz212 Apr 21 '15 at 18:19
@Zizouz212 Cool! Nice answer also – Bhargav Rao Apr 21 '15 at 18:25

score 1 · Answer 2 · answered Apr 21 '15 at 18:21

As an addition to Bhargav's answer, I figured I would mention one other option:

while True:
    try:
        x = int(input("Write a number: "))
    except ValueError:
        print("You must write a number: ")
    else:
        break

The try statement executes. If an exception is thrown, the except block takes over, and it's run. The else block is executed if no exception is thrown. And don't worry, if the except block ever executes, the else block won't be called. :)

Also, you should note that this answer is considered to be more Pythonic, while Bhargav's answer is arguably easier to read and more intuitive.

How to run a while loop as long as there is no error

2 Answers2

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