Loops

Loops #


What are loops? Loops are used for doing a task a specific number of time, but it also has other uses which we will be exploring below and later on


Types of Loops #

There are two types of loops that we will be introducing here

  • For Loops
  • While Loops

For Loops #

Usually, for loops are used for iterating over a sequence of objects

Here is an example in which we see that we have a list and we use the for loop to print out items in the list one by one

team = ['Pichu', 'Pikachu', 'Raichu']
for pokemon in team:
    print(pokemon)

This will result in the following being printed out to console

Pichu
Pikachu
Raichu

What we did here was first we make a list named team which ended up including string objects. The second like essentially said, for every pokemon in list team , print the pokemon object

So that is why we had the names of the pokemon inside team printed out


While Loops #

We have seen what we can use for loops for, now lets see what we can do with a while loop . In a while loop, we have to set a condition, and it will continue to run until the condition is deemed to be false

Here is the basic syntax of the while loop

while(condition is true):
    run code

As stated before, if the condition is true, only then the code run

If the condition never turns false, the while loop will keep on running infinitely, which will cause your program to crash

Here is an example of a while loop which will do the same thing that we did using the for loop before

team = ['Pichu', 'Pikachu', 'Raichu']
index = 0
while index < len(team):
    print(team[index])
    index += 1
Line Number Explanation
1 Here we are defining a list named team with the elements 'Pichu', 'Pikachu', 'Raichu (which are strings) in it
2 We are defining a counter variable, named index , for the condition which will track our location within the list. Remember that the index of a list will start at 0 and not 1
3 Here we are entering our while loop , the condition we are setting is that as long as the value of our counter variable, index , does not exceed nor equal the value of the length of the list, we will continue
4 We are now using the counter variable, index , to access the current item in the list, team , and printing it out
5 Finally, we are adding a 1 to the value of the counter variable, index , each time the while loop runs. Without this, we will be accessing the same item over and over again, and the condition will also not even turn false, resulting in a infinite loop