Perl Tutorial - 41: Miscellaneous Operators Video Lecture | Perl Building Blocks: An Introduction to Perl - Back-End Programming

hi guys welcome to my channel this is
the 41st roll in this playlist and in
this role we'll be talking about some
miscellaneous operators in Perl and
these are operators we haven't talked
about in the last five or six tutorials
that we had on operators and some of
these are actually quite interesting and
you might want to play with them and use
them often in your Perl scripts so I
have a script here that's called
miscellaneous underscore operators and
in the script on line number three I
have created a scalar variable called my
underscore string which has the text
I'll be back with an exclamation symbol
and a space now let's say you want to
display the string 20 times on the
screen you could do that by typing the
print statement 20 times although that
would be very time-consuming and stupid
or you could create a loop that would
have 20 hydrations and you know write
the print statement in it just once and
you know that would be a smarter
approach but again in Perl you don't
even have to do that to print a string
you know a given number of times you
just have to put the alphabet X in
lowercase between the string and the
number of times you want to display it
so you know if you want to display it 20
times and you would have to type my
underscore string the alphabets X and
then 20 and of course this has to go
along with the print statement and by
the way I have this within parentheses
so you know that's change and this
string would be displayed 20 times and
we're going to check out the output in a
while after I finished talking about the
other operators and the next one that
we're going to check out is the range
operator and this one we've already seen
a couple of times in the course and it's
you know for autocomplete basically
let's say you want to create an array
variable called my underscore list in
which you want to put numbers from 1 to
10 like 1 2 3 4 so on till 10
you could either type all the numbers
like 1 comma 2 comma 3 comma 4 so on and
so forth
that's okay if you want to create a list
of 10 numbers but let's say you want to
create a list of 50 numbers it would
take a lot of time to type numbers from
1 to 50 and you know commas in between
so if you want to do something like this
and you could use a range operator which
is nothing but 2 dot symbols put
together
so within parenthesis you would type 1
and then double dots and then the end
value which in our case would be 10 and
then I have a print statement on line
number 7 to see the output from the list
my list and then let's move on to the
pre and post increment and decrement
operators so I've got a scalar variable
called my underscore where on line
number 9
I filled it with the value 20 now let's
say you want to add 1 to this variable
and by that I mean increment it by 1 and
also see the value so if you want to add
the you know value 1 to the variable
before displaying it then you would
actually use the pre increment operator
and that is nothing but you know the
plus symbol used twice so I have a print
statement on line number 10 with two
plus symbols before the variable name so
you know these are going to update my
bar make it twenty one and then display
the value so from this print statement
we should see 21 as the output and
similarly the decrement operator would
subtract one from the variable and then
display the value so the print statement
on line number 12 should give us 20
because here
my bad would have been changed to 21
this would again bring it back to 20 and
show the value and then post increment
and post decrement operators let you
display the value and then actually make
the change so if you would use the plus
plus symbol after the variable
name like I have in the print statement
on line number 14 then we would first
see the value and then the value would
be updated after this print statement
has you know done its job so the value
would be changed for twenty-one and just
to ensure that that has happened I have
another print statement on line number
fifteen to just see the value in my
world so this should sort twenty and
then this should show 21 and similarly
for pause decrement over here we will
see 21 as the value and then the
decrement will happen after this print
statement has executed we will come back
to 20 and then I have a print statement
on line number 18 to see the value in my
eval so eventually we should see 20 as
the final value so I'll save the file
and I will press f5 to execute it and
there we go first of all we see the text
I'll be back
20 times and then we see numbers from 1
to 10 in the list my list so the range
operator and the repeat operator those
two have done their job and then finally
we see all these numbers so for
pre-increment we see 21 pre-decrement we
see 20 and then for post-increment we
first see 20 and then we see 21 and then
for post decrement we first see 21 and
then we see 20 so that's it in this
video I hope you guys had fun watching
this tutorial you may subscribe to my
channel if you haven't already I am
going to see you in the next video till
then take care