How to solve the infinite loop problem in Python

In Python, you can use the for or while instructions to perform loop processing. If the permanent loop does not end, it is called an infinite loop. In the following article, we will take a look at how to solve the problem of infinite loops in Python.

Let’s first briefly look at an example of an infinite loop

while True:
    print("hello")

When executing this program, since the condition of “while” is always “True”, therefore hello will always be output. Additionally, infinite loops may be created unintentionally. For example, consider a program that displays a value when the user enters something and ends if there is no input.

while True:
    s = input("请输入内容")
    if(s):
        print(s, "输入的文字")

In this case, if the user does not enter anything, the program can end. Therefore, there is no way to go through the loop process, so it will loop infinitely. Here's a slightly more complicated example.

l = [0]

for i in l:
    print(i)
    l.append(i+1)

In this case I am adding an element to the list "l" in a loop. Therefore, the for statement will never complete at any point and it will loop endlessly. This is an incorrect process, so the program needs to be reviewed.

Unintentional infinite loops can consume excessive amounts of computer memory and CPU. First, we need to check the program to prevent it from accidentally becoming an infinite loop. Most importantly, if you use infinite loops, we need to have a way around it. So, let’s take a look at How to solve the problem of infinite loop

We can use the break method to escape from the infinite loop, and we can use the break method to exit the loop during loop processing.

Let’s look at specific examples

Let’s modify the above program so that it no longer loops infinitely

First of all

while True:
    print("hello")

The following is an example modified using the break method. In this case, we modify it so that it ends after looping 10 times.

i = 0
while True:
    print("hello")
    i += 1
    if (i ==10):
        break

followed by

while True:
    s = input("请输入内容")
    if(s):
        print(s, "输入的文字")

changes to

while True:
    s = input("请输入内容")
    if(s):
        print(s, "输入的文字")
    else:
        break

and finally

l = [0]

for i in l:
    print(i)
    l.append(i+1)

In this case, let’s prepare beforehand It is best not to add elements to the list during the loop.

l = [0, 1, 2, 3, 4]

for i in l:
    print(i)

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