Hello
gowthamvels and welcome to the monastery and to the wonderful world of Perl!
Next time please show the code you tried: generally monks prefere (with reason) to see some effort from the wisdom seeker.
You already got wise answers and smart ones too. Mine is a oneliner (be aware of windows double quotes: use single quote on Linux).
perl -F"," -lanE "$h{join ',',@F[0,1]}+=$F[2]}{map{say $_.','.$h{$_}}s
+ort keys %h" sample.csv
3211111,100,4.4
3211112,100,2.5
3211112,101,3.2
3211113,100,5.2
See perlrun to know how many useful switches and parameter you can feed to Perl!
Basically speaking -a autosplits incoming strings (at spaces), feeding the special @F array (see perlvar for it)
-F specify an alternative pattern for the autosplit
-l uses a smart line handling
-n wraps your program into a while loop without printing his input ( -p also print it)
-E executes the following code and import some feature (like say I used). Normally you can use -e
}{ is a trick: see eskimo greeting
If the oneliner seems overhelming for you, use -MO=Deparse to have it expanded:
perl -MO=Deparse -F"," -lanE "$h{join ',',@F[0,1]}+=$F[2]}{map{say $_.
+','.$h{$_}}sort keys %h" sample.csv
BEGIN { $/ = "\n"; $\ = "\n"; }
BEGIN {
$^H{'feature_unicode'} = q(1);
$^H{'feature_say'} = q(1);
$^H{'feature_state'} = q(1);
$^H{'feature_switch'} = q(1);
}
LINE: while (defined($_ = <ARGV>)) {
chomp $_;
our(@F) = split(/,/, $_, 0);
$h{join ',', @F[0, 1]} += $F[2];
}
{
map {say $_ . ',' . $h{$_};} sort(keys %h);
}
-e syntax OK
If you are really lazy you can learn what switches do using MO=Deparse adding them progressively and seeing what happens executing a noprogram ( is what perl -e 1 is, marked by '???' in the deparsed output):
perl -MO=Deparse -e 1
'???';
-e syntax OK
perl -MO=Deparse -n -e 1
LINE: while (defined($_ = <ARGV>)) {
'???';
}
-e syntax OK
perl -MO=Deparse -n -a -e 1
LINE: while (defined($_ = <ARGV>)) {
our(@F) = split(' ', $_, 0);
'???';
}
-e syntax OK
perl -MO=Deparse -n -a -F"," -e 1
LINE: while (defined($_ = <ARGV>)) {
our(@F) = split(/,/, $_, 0);
'???';
}
-e syntax OK
perl -MO=Deparse -n -a -F"," -l -e 1
BEGIN { $/ = "\n"; $\ = "\n"; }
LINE: while (defined($_ = <ARGV>)) {
chomp $_;
our(@F) = split(/,/, $_, 0);
'???';
}
-e syntax OK
perl -MO=Deparse -n -a -F"," -l -E 1
BEGIN { $/ = "\n"; $\ = "\n"; }
BEGIN {
$^H{'feature_unicode'} = q(1);
$^H{'feature_say'} = q(1);
$^H{'feature_state'} = q(1);
$^H{'feature_switch'} = q(1);
}
LINE: while (defined($_ = <ARGV>)) {
chomp $_;
our(@F) = split(/,/, $_, 0);
'???';
}
-e syntax OK
L*
There are no rules, there are no thumbs..
Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.
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