Using else conditional statement with for loop in python
In most of the programming languages (C/C++, Java, etc), the use of else statement has been restricted with the if conditional statements. But Python also allows us to use the else condition with for loops.
The else block just after for/while is executed only when the loop is NOT terminated by a break statement.
Else block is executed in below Python 3.x program:
for i in range ( 1 , 4 ): print (i) else : # Executed because no break in for print ( "No Break" ) |
Output :
1 2 3 No Break
Else block is NOT executed in below Python 3.x program:
for i in range ( 1 , 4 ): print (i) break else : # Not executed as there is a break print ( "No Break" ) |
Output :
1
Such type of else is useful only if there is an if condition present inside the loop which somehow depends on the loop variable.
In the following example, the else statement will only be executed if no element of the array is even, i.e. if statement has not been executed for any iteration. Therefore for the array [1, 9, 8] the if is executed in third iteration of the loop and hence the else present after the for loop is ignored. In case of array [1, 3, 5] the if is not executed for any iteration and hence the else after the loop is executed.
# Python 3.x program to check if an array consists # of even number def contains_even_number(l): for ele in l: if ele % 2 = = 0 : print ( "list contains an even number" ) break # This else executes only if break is NEVER # reached and loop terminated after all iterations. else : print ( "list does not contain an even number" ) # Driver code print ( "For List 1:" ) contains_even_number([ 1 , 9 , 8 ]) print ( " \nFor List 2:" ) contains_even_number([ 1 , 3 , 5 ]) |
Output:
For List 1: list contains an even number For List 2: list does not contain an even number
As an exercise, predict the output of following program.
count = 0 while (count < 1 ): count = count + 1 print (count) break else : print ( "No Break" ) |
This article is contributed by Harshit Agrawal. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.
Recommended Posts:
- with statement in Python
- Python Continue Statement
- Python return statement
- Python break statement
- Statement, Indentation and Comment in Python
- How to write an empty function in Python - pass statement?
- Python | Using for loop in Flask
- Print first m multiples of n without using any loop in Python
- Conditional operation on Pandas DataFrame columns
- NLP | Storing Conditional Frequency Distribution in Redis
- Create a pandas column using for loop
- Create a column using for loop in Pandas Dataframe
- Python | Convert list to Python array
- Python | Merge Python key values to list
- Important differences between Python 2.x and Python 3.x with examples
Improved By : tarun2207