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