Perl Tutorial - 26: Until Loop Video Lecture | Perl Building Blocks: An Introduction to Perl - Back-End Programming

hello guys welcome to my channel this is
the 26 to role in this course and in
this role we'll be talking about the
untell loop in Perl
so the under loop is like the exact
opposite of the while loop
just as the unless statement was the
opposite of if and you know in while
loop you keep on executing the code
that's in side the while block till the
test condition is true in until loop you
keep on doing the same thing as long as
the test condition is false right so
that's the only difference and
syntactically they are pretty much the
same so to demonstrate the anti loop
I've got a script that's called untilled
and in the script on line number 3 I
have created a scalar variable X which
has a value 10 and the objective is the
same we have to print values from 10
till 20 and this time you are also going
to print 20 I haven't put the equal to
symbol here and you know instead of the
wild keyword we have the until keyword
here and then within parentheses the
test condition is also slightly
different so instead of putting door X
less than equal to 20
we have door X is greater than 20 so you
know with X having the value 10
initially the condition is false right
because 10 is not greater than 20 and as
long as that is going to be the case we
are going to execute whatever is there
inside the until block and we have two
statements on line number seven there is
a print statement which is just going to
display the current value of X and then
on line number eight we have an update
statement so we are increasing the value
of x by one in each iteration of the
loop and X is going to change from ten
to eleven to twelve so on and so forth
till 21 and when it becomes 21 it's
going to be greater than 20 and that's
when this condition is going to be true
and until is going to stop executing so
it's fairly simple I'll execute the
script and show you the output so there
it is numbers from ten till two
and if of course you don't want to see
20 then all you have to do is put an
equal to symbol head and rerun the
script in this time you will see numbers
from 10 to 19 so that's it for this
tutorial I hope you guys had fun
watching this video you may subscribe to
my channel if you haven't already I will
see you in the next tutorial till then
take care