Ruby Programming Tutorial - 17 - Loops Video Lecture - Introduction

what is going on guys welcome to your
17th Ruby tutorial and I want to start
out this tutorial by talking to you
about something called loops now a loop
is pretty much code that runs multiple
times automatically so let me go ahead
and show you guys an example and then
I'll talk you guys through go ahead and
write eight dot times du puts and I'll
just write like bacon or something and
now what this does is whenever we hit
enter is it prints out the word bacon
eight different times now let me go
ahead and talk to guys about this
command first of all times is basically
a method that runs code a certain number
of times so this is a method that's
getting run on the eight right here now
again as you can see a loop basically
puts bacon eight different times so it
basically run this code eight times so
in order to make a loop and this is
there are a lot of different kinds of
loops but this is the most simple one
you go ahead and write a number with x
and then whatever code you want to
repeat you put it between the keyword do
and end so what do we want to do eight
times well we just want to print out the
word bacon on the screen and if a lot of
people they have trouble understanding
that the code that you want to run has
to go in between the do in the end
keyword because there's just too many
keywords so there is an alternative
syntax and that's instead of the do in
the end keyword you can just use curly
braces instead and put the code inside
so you can have something like this four
times and there isn't any do or any
keyword just go ahead and write the code
that you want to repeat in between curly
braces and I know those curly braces
look kind of weird but it's the key to
the right of the P on your keyboard if
you hold shift you see those little
curly braces above the square brackets
those ones even though these ones kind
of look like backwards seas or whatnot
so let's just go ahead and print out the
word putting hammock spelled incorrectly
putting Hancock oh that's classy so now
we go ahead and hit enter and check it
out the word putting cam
Kollek prints out four times right on
the screen so like I said this is pretty
much the most simple type of loop but
there are alternative types of loop so
let me go ahead and show you guys
another one one of the types of loop
instead of just writing how many times
you want to print something out you give
it two numbers the first number is where
you want to start counting and the
second number is it pretty much counts
to that number so I'll show you guys an
example like um 3 up 2 and let me just
give it another number now for these the
parameters that we have to use have to
go in between just regular parentheses
so let's count from 3 up to 7 and what
do we want to do let's just go ahead and
put something stupid count from 3 to 7
now go ahead and hit enter and check out
what happens this code is going to run
five times why does it run 5 times well
what it's going to do is it's going to
start with 3 and it's going to count all
the way up to 7 so 3 4 5 6 7 that's 5
different times so again instead of just
giving it a single number and say run
this code that many of times you can
give it two numbers and it's going to
pretty much count 3 4 5 6 7 and when it
gets to the end it's going to stop
running the code now alternatively you
also have kind of the opposite of this
up to and down to so you can count from
like 15 down to 12 or something and
whenever you do this it's going to run
the code from 15 14 13 12 so let's go
ahead and see what happens
so puts move my mouse puts and what do
we want to write this time this one
counts down
and I have one extra okay Bucky come on
focus focus here I hate this little
cursor I just wish it was a line
my name is go ahead and hit enter and
check it out 15 14 13 10 so pretty much
it starts at 15 and counts down to 12
therefore it loops the code four
different times now the last loop that I
want to talk to you guys about in this
tutorial is the step loop now what the
step loop does is it starts at a number
and it counts to a bigger number let's
say but it steps not in increments of
one it gives it alternative increments
and sudden me trying to explain that
I'll just go ahead and show you guys an
example so zero step and in here you
give it two parameters let's say 15 and
five so now what we're going to do is
just print out on the screen
um zero to 15 by 5's so let's go ahead
and hit enter and check it out it loops
one two three four times why does this
happen well what it does is you pretty
much give it two values the zero is your
starting point the 15 is your ending
point but instead of looping 15 times we
say hey don't count by ones anymore
count by 5's so the values that got
inputted whenever we looped were 0 5 10
and 15 so like I said instead of pretty
much looping by 1 we can loop by
different values using this step loop so
again those are different types of loops
probably the easiest one is just this
times one where you say okay loop this
amount of times but there are
alternative ones and again I'm going to
show you why a loop is useful in the
upcoming tutorials and I'm also going to
show you guys how to extract the value
from that loop in the next tutorial so
thank you guys for watching don't forget
subscribe and I'll see you guys later