Perl

Perl (for me)

1. How chomp can be screwed up

########################

#! /usr/bin/perl -w

$/="something";

chomp ($name = );

#chomp $name;

print "$name\n";

########################



Now what happens is chomp won't remove the newline. It will remove
'something'!!!

This is because $/ by default is set to "\n" and we have set it to
'something'.

Good thing to remember.

2. Something about Lists

########################

#! /usr/bin/perl -w

@abc= ("a","b","c","d");

print @abc,"\n";

print "@abc\n";

########################

OUTPUT

abcd

a b c d

3. Printing arrays in so many ways (Look at ***5***)

#######################

#! /usr/bin/perl -w

@abc= ("a","b","c","d");



print "\n***1***\n";

for ($x=0;$x<=$#abc;$x++) { print "$abc[$x]"; } print "\n***2***\n"; for $x (0..$#abc){ print "$abc[$x]"; } print "\n***3***\n"; foreach $alphabet (@abc){ print "$alphabet"; } print "\n***4***\n"; foreach (@abc){ print "$_"; } print "\n***5***\n"; foreach (@abc){ print ; }

print "\n***6***\n";

print @abc[0..$#abc],"\n";

4. Using 'Last'

#######################

#! /usr/bin/perl -w

@alphabets = ('a','b','c','d','e','f','g','h','i');

foreach $letter (@alphabets) {

print "$letter\n";

last if $letter=~/e/;

}

#######################

5. Splice

#######################
#! /usr/bin/perl



@vowels = ('a','e','i','o');

@alphabets = ('a','b','c','d');

&display;

splice (@vowels,0,0, @alphabets);

&display;


sub display{

print "Vowels: @vowels\n";

print "Alphabets: @alphabets\n";

}
#######################


6. HASH

########################

foreach $x (sort hash_val_descending (keys(%hash_val))) {
print OUTFILE "$x \, $hash_val{$x} \n";
}
print "\nOUTPUT FILE: merged.csv\n";

close OUTFILE;
close INFILE;
}

sub hash_val_descending {
$hash_val{$b} <=> $hash_val{$a};