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In previous section, you learned how to make a simple list and you learned how to work with individual

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elements in list.

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In this section, you will learn how to loop through an entire list using just a few lines of code,

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regardless of how long the list is.

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So looping allows you to make the same action or set of actions with every item in a list.

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As a result, you will be able to work efficiently with a list of any length, including those with

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thousands or even millions of items.

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And you will often want to run through all entries in the list.

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So performing the same task with each item.

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For example, in a game you might want to move every element.

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But on the screen to the same account practice.

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Um, or in a list of numbers you might want to perform the same statistical operation on every element.

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Or perhaps you will want to display each headline from a list of articles on a website.

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So when you want to do the same action with every item in a list, you can use The python's for loop,

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Python's for loop.

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So say we have a list of magician's names and we want to print out each name in the list.

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We could do this by retrieving each name from the list individually, but this approach could cause

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several problems here.

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For one, it would be repetitive to do this with a long list of names.

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Also, we'd have to change our code each time the list length created and using the for loop avoids

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both of these uses by letting Python manage these uses internally.

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So let's use a for loop to print out each name in a list of magicians.

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So here actually mutations.

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So just like that.

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Yes.

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So, magicians.

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And let's actually make it Alice.

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Alice.

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David.

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David and Carolina.

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And here we will create a for loop here.

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So for magician.

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In magicians.

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And after that we will print the magician every time.

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And here we begin by defining a list, just as we did in previous lectures.

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Oops.

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Here, let me fix my mouse right now.

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Yes.

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So here we go.

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We begin by defining a list, just as we did in previous lectures here.

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So.

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Then we define a for loop.

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This is new to us, right?

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So then we define the for loop.

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So this line.

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Tells Python to pull a name from the list.

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Magicians.

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And.

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Associated with the variable name magician.

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Next we tell Python to print the name that just been assigned to this magician here.

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Biden then repeats these last two lines, one for each name in the list.

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It might help to read this code as like this.

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So here we for this code, we have this explanation.

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Every magician in the list of magicians.

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Magicians.

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Print the magician's.

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Nay.

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So the output is simple printout of each name in the list.

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Let's try this out.

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As you can see here, we printed every user in the in the our magicians list without a problem.

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Now looping is important because it's one of the most common ways of computer automates repetitive tasks.

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For example, in a simple loop like we used in this file, in this lecture.

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Here.

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Python initially reads the first line of the loop.

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This line here.

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So this line tells Python to retrieve the first value from the list magicians and associated with the

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variable magician and the first value here.

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So here, actually, let me write that down here.

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Okay.

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So the first value here, The first.

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Oh, sorry.

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Here.

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The first value here.

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Is Alice, right?

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Yes.

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The first value here is.

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And the second value.

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And I'll also python prints the first value as Alice and the current.

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This is the current value of magician right now which is still Alice because the list contains more

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values and Python returns to the first line of the loop.

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Right.

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So Python retrieves the next name in the list, which is.

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In this case.

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David Right.

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So Python also retrieves the.

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David.

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And associates that value within the variable magician here.

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And Python then executes the line which is print the magician and Python prints the current value of

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magician again which is now is David and Python repeats the entire loop once more with the last value

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in the list, which is Caroline.

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This here.

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So because no more values are in the list.

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Python moves on to the next line of the program.

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In this case, nothing.

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Nothing comes after this line here.

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So this is empty here for now.

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And.

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And nothing comes after the for loop.

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And so for loop will end here.

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So when you are using the loops for the first time, keep in mind that the set of steps is repeated

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once for each item in the list.

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So no matter how many items are in the list and how much.

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So if you have a million items in your list, the python repeats these steps a million times and usually

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very quickly.

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Also, keep in mind when writing your own for loops that you can choose any name you want for the temporary

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variable.

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That will be associated with each value in the list.

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So however itself will do, choose a meaningful name that represents a single item for the list.

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So for example, you can.

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Let's actually create a good way to for naming these loops here.

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So another good way for naming this loop is, for example, look for Cat in cats or for dog in dogs

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or for item in list of items.

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Okay, so these are the just examples that you can name your loops.

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So to make it more meaningful and readable.

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Right.

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So these naming conventions can help you to follow the action behind being done on each item within

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a for loop.

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And using singular and plural names can help you identify whether a section of code is working with

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a single element from the list or the entire list at.