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This article mainly introduces the relevant knowledge of "how to use else in Python". The editor shows you the operation process through an actual case. The operation method is simple, fast and practical. I hope this article "how to use else in Python" can help you solve the problem.

Generally speaking, it is executed when there is nothing wrong with for, while and try statements, while else is executed only when if statements are judged to be false (faulty) in if..else statements, which should be distinguished.

The following example illustrates the role of while..else. The string has a s1.find (S2) method, which is used to find S2 in the string S1. If it is found, it returns its index value. There is no return of-1, but there is no find method in the list. The following uses while... The else statement implements the list_find method:

Or simulate the implementation of list.index ():

Finally, about try... .account1... roomt2... Else... The execution order of finally: when there is no problem with try execution (that is, no exception is caught in each except statement), then execute the else statement, and finally execute the first and last work of finally. If any exception is caught by except during execution, skip else and execute finally directly.

You don't know the use of else if-else

If-else is basically a general branch selection structure in any language. Here is a brief introduction.

If 3% 2 else 1: print ("if") else: print ("else")

If if-else satisfies if, it will enter if chunk, otherwise only one chunk code will be executed when entering else chunk if and else.

For-else

I have only encountered the use of for-else in the learning process of python. Compare with test cases.

Fruits= [apple "," orange "," pear "] for item in fruits: if item==" apple ": print (" apple ") else: print (" for-else ")

↓↓↓

Applefor-else

Here the for loop ends normally, and then the code for the else chunk is executed.

Fruits= [apple "," orange "," pear "] for item in fruits: if item==" apple ": print (" break ") breakelse: print (" for-else ")

↓↓↓

Break

When the break statement is executed out of the loop in the for loop, the else chunk is not executed.

That is, when for-else is used together, if the for loop does not jump out of the loop because of the break statement, the else statement will be executed.

While-else

While-else is similar to for-else in that else chunks are executed at the normal end of the previous cycle.

I=5while I > 0: i=i-1else: print ("while-else")

↓↓↓

While-else

The while statement executes normally. When the while condition is false, it ends the while loop and enters the else chunk.

I=5while I > 0: i=i-1 if iTunes 3: print ("break") breakelse: print ("while-else")

↓↓↓

Break

While statement because the break statement jumps out of the loop, the else chunk is not executed.

When while-else is used together, if the while loop does not jump out of the loop because of the break statement, the else statement will be executed.

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