Day 15 - Else¶
As you saw in Error Handling, we can use the else clause not only with conditionals, in this case we’ll see that we can use this clause with other statements.
For/Else¶
Before we explain how we can include the else, we’ll create a loop like the one below:
numbers = range(10, 21)
for number in numbers:
print(number)
The previous loop will print the numbers from 10 to 20.
If you are familiar with loops, you will know that the break sentence will interrupt the execution and continue outside of it.
numbers = range(10, 21)
for number in numbers:
if number == 17:
break
print(number)
The previous loop will print the numbers from 10 to 16, when the number 17 continues, the conditional will validate it and the loop will be interrupted, so the execution will continue.
However, there are cases when we are going through some kind of data we will realize that the loop ended without finding a break, in these cases is when we can make use of the else clause.
numbers = range(10, 21)
for number in numbers:
if number == 60:
break
else:
print("Number 60 was not found")
The else clause is executed when a loop is not interrupted, and will only execute the block of code when the loop is over.
While/Else¶
The while statement also allows the use of the else clause, and like the for loop, it will only be executed if no break is found in the while block.
while conditional:
# Do some stuff with possibilities of break
else:
# Do some stuff if no break executed