Perl Tutorial - 37: Comparison Operators (Strings) Video Lecture | Perl Building Blocks: An Introduction to Perl - Back-End Programming

hello guys welcome to my channel this is
the 37th tutorial in this course and in
this tutorial we'll be talking about
comparison operators in Perl for Strings
so in the last tutorial we checked out a
bunch of comparison operators that work
with the numbers in this tutorial we're
going to see the corresponding operators
that can be used with the text data so
you know I have a script opened up here
that's called comparison underscore
operators underscore strings and in this
script on line number three I have
created a scalar variable X which has
the value world and it's been enclosed
in double quotes which means that's a
string of text and then on line number
four I have created a variable Y which
has the value hello so words in a
dictionary are arranged in alphabetical
order and if you would take a word that
starts with the alphabet a and if you
would compare it with a word that starts
with the alphabet Z then you know you
could say that the word that starts with
Z is greater than the word that starts
with a because it appears on a page
number that's greater and you know
that's the sense that has been embedded
in Perl so if you would run the check
Dora X less than dollar Y then it would
see the position of the two words in a
dictionary you know like I don't know if
that's how it works exactly but of
course it looks at the ASCII value of
the first character in the two words
maybe and on the basis of that it
decides whether the you know the
condition would evaluate to true or
false so anyway the corresponding
comparison operator in strings for the
less than symbol for numbers is LT so
it's a short form for less than and
similarly you have GT for greater than
you have le for less than equal to you
have GE for greater than or equal to you
have EQ for equal to so this is you know
to the double equal to operator that we
use with numbers and then you have any
for not equal to which is the same as
the exclamation equal to operator for
numeric values so I have a bunch of if
statements in the script and I use I've
used these operators to compare the
value stored in variables x and y and on
the basis of you know what we get from
the if statement we are printing some
lines of text so anyway I'll make sure
that the script is saved and I'll run it
to show you the output so we see that
world is greater than hello and that's
because the rank of world in a
dictionary would be more than the rank
of hello and then world is greater than
or equal to hello of course it's greater
than that's why we are seeing this
message and then world and hello are not
the same and I close this window and
I'll change hello to something else or
you know it would be easier if I change
world to Apple and I'll run the script
and now we see Apple is less than hello
Apple is less than or equal to hello and
Apple in hello are not the same and then
finally I would change hello to Apple
and see how that would work and we see
Apple is less than or equal to Apple
Apple is greater than or equal to Apple
and Apple and Apple are the same so it
works perfectly I mean all the operators
we've seen the syntax now so I hope this
gives you the knowledge that's required
to compare string values in Perl and
Perl was actually designed to be a
language for text fish I think somewhere
down the line it has just lost that
reputation Python is now the most
popular language for text processing and
you know text mining and all and Perl is
still a popular language but I don't
know how many people in the world use
pearl for text mining anyway I hope you
guys had fun watching this video you may
subscribe to my channel if you haven't
already I'm going to see you in the next
video
then take care