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For loops are used to process steps one at a time, and you have a bit of control over how you step through each pass of a loop.
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[MUSIC]
0:00
Hey there.
0:04
I know that loops, both the for and
0:05
the while varieties,
can be a bit tricky to understand.
0:07
We're used to doing things
repetitively in real life, but
0:10
sometimes translating things from real
life to programming can be a bit weird.
0:12
So let's do a bit more
practice with loops so
0:16
they will hopefully make a bit more sense.
0:18
I have two files here in the workspace.
0:21
The first one is named for.py and
that is for practicing for loops.
0:23
And the second one, while.py,
is for practicing while loops.
0:27
So I'm gonna show you the problems for
each of them in the appropriate videos.
0:32
You can then stop the video and write
the code yourself to solve the problems.
0:36
If you get stuck or you just wanna
see how I solved my problem,
0:40
then just watch the next video and
you'll see how I did it, all right?
0:43
Let's get started with for loops.
0:46
For a brief refresher on for loops,
0:49
they're loops that work their way
through the items in an iterable.
0:52
So you'd have for and then
some_variable in [1, 2, 3], all right?
0:57
Something like that.
1:05
For each iteration of the loop, each trip
through it, it will take the next item
1:06
from the iterable, and it will put it
into whatever variable name we've given.
1:10
And then it will execute the code
that's inside the loop and
1:15
the loop will end when
the last item is processed.
1:19
Here in for.py, I have a few
problems outlined in the comments.
1:25
And at the top of the file there is a
tuple of people, their birthdays, whether
1:29
or not they like to celebrate their
birthday, and how old they're going to be.
1:34
If you're not sure what a tuple is,
1:37
it's just like a list except
you can't change its contents.
1:38
It's actually the reason
why I'm using a tuple.
1:42
So that you don't
accidentally change anything.
1:43
One less thing for you to worry about.
1:45
So let's look at these problems.
1:47
For the first one, called Celebrations,
I want you to loop through each person
1:49
that's in the tuple, and if they celebrate
their birthday, print out their name.
1:53
Print out like, Happy Birthday Sam.
1:58
Although Sam doesn't celebrate, so
that wouldn't be the right one to print.
2:01
For the second problem right here,
Problem 2: Half Birthdays,
2:05
you're going to have to do some math.
2:07
Loop through the tuple again and for each
person figure out their half birthday.
2:10
If you're not familiar
with a half birthday,
2:13
it's the day that's exactly six
months after or before your birthday.
2:16
So it's your birthday on
the other side of the year.
2:19
A little extra reason to
eat cake never hurt, right?
2:22
For example, for Kamal here,
their birthday would be October 29th,
2:25
since they were born in April 29, or
2:30
29/10, keeping this day
slash month format.
2:33
The third problem is similar to the first.
2:38
Loop through the tuple again and for each
person, if their birth month is between
2:40
9 and 6, so 9 to 12 or 1 to 6,
then print out their name.
2:45
So if they have their birthday
during a typical school year.
2:49
And finally, for
2:54
the fourth program, you can probably
guess, the first step is a loop.
2:54
Then if the person celebrates their
birthday and they're ten years old or
2:59
less, print out however
many stars their age is.
3:02
For example, if they're turning nine,
you'd print out nine stars.
3:05
Feel free to use any and all Python
techniques that you're comfortable with
3:09
for this practice session.
3:11
The only thing you should definitely try
and use for every problem is a for loop.
3:13
You might need to turns strings into
numbers, create ranges, and more though.
3:17
I'll see you in the next video for
my solution.
3:21
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