How to stop the while loop?

Question

Newbie in programming and need something like this but it doesn't stop the while condition even after entering a string starting with '0x', and it keeps calling the function.I tired putting 'break' instead of increasing i value, still didn't work. Any one knows why?

i = 1
while i < 2:
    call_fun1()
    if hx =='0x':
        i+=1

What is `hx`? If it never equals the string `0x` your loop will never end. — Francis Avila, Sep 07 '13 at 20:23

score 1 · Accepted Answer · answered Sep 07 '13 at 20:42

1

The above code will run into an infinite loop only when the while condition

while i < 2:

always turns out to be true. This will happen when the code section that is changing the value of i, i.e.

i+=1

is never executed. This will happen when the if condition

if hx =='0x':

always turns out to be false.

So check why

if hx =='0x':

is always evaluated to false. This should fix the problem.

answered Sep 07 '13 at 20:42

Sureshkumar Saroj

109
2

Rewrite the if condition as `if hx.startswith('0x')`. – Sureshkumar Saroj Sep 07 '13 at 20:49
1

Also, you have not shown how `hx` is assigned values. Since the variable part in expression `if hx =='0x':` is `hx`, you also need to make sure that `hx` is updated somewhere inside the while loop. – Sureshkumar Saroj Sep 08 '13 at 06:00

score 0 · Answer 2 · edited May 23 '17 at 11:56

0

With if hx =='0x', you are checking if hx equals "0x", not if it starts with it. You need to find a 'substring'. Check this question: Examples for string find in Python

Because of this, i is never incremented and therefore the loop will continue indefinitely.

edited May 23 '17 at 11:56

Community

1
1

answered Sep 07 '13 at 20:40

Alfie

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How to stop the while loop?

2 Answers2