Using else conditional statement with for loop in pythonIn 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:
Pythonforiinrange(1,4):print(i)else:# Executed because no break in forprint("No Break")
Output :
123No Break
Else block is NOT executed in Python 3.x or below:
Pythonforiinrange(1,4):print(i)breakelse:# Not executed as there is a breakprint("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 the third iteration of the loop and hence the else present after the for loop is ignored. In the case of array [1, 3, 5] the if is not executed for any iteration and hence the else after the loop is executed.
Python# Python 3.x program to check if an array consists# of even numberdefcontains_even_number(l):foreleinl:ifele%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 codeprint("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 numberFor List 2:list does not contain an even number
As anexercise, predict the output of the following program.
Pythoncount=0while(count<1):count=count+1print(count)breakelse:print("No Break")