## ~ For Loops

### For loops

For loops tell the computer to do something for a bunch of values. They're particularly useful when we want the same "thing" done several times in succession.

## Many print statements, no for loop

Let's say, for example, we wanted to print out the numbers 0-5 in sequence. We could write print statements:

But that seems tedious!

## For loop and a list

We could also put the numbers we want in a list and then print each thing in the list:

That seems a little better.

On the first line, we make a list, called `numbers`, and fill it with the numbers we wish to print: `[0, 1, 2, 3, 4, 5]`.

On the second line, we write `for n in numbers:` This is the for loop part, and converted into English, it says "Look at the list called `numbers`. For each element in it, grab the element and temporarily call it `n`. Then .. "

On the third line, we write `print` just once, and ask Python to `print n`. That's the same as asking Python to print out the value in the variable container `n` – which we know is one of the elements in the list from the second line!

## For loop and `range( .. )` function

There's a special `range( .. )` function built into Python that gives back a range of numbers. Try running the code below:

Here we get the same result, though we didn't have to make a list ourselves. The `range(0, 6)` function gave us one that went from 0 (inclusive) to 6 (exclusive.)

## General form of a for loop

The general form of a for loop looks like this:

``````for temp_variable in some_sort_of_list:
do_something
``````

## Doing things with for loops

For loops end up being pretty useful. Take a look at the code below; when you think you know what it does, click 'Run', and take a look:

That for loop sums the numbers between 0 and 100.