CODEWITHSUNDEEP
perl
sfgroups
sfgroups

Reputation: 19109

Perl add delimiter and remove last one

I have file with few lines, I want combine all lines with delimiter and remove the last one.

Its not working with perl. but working with sed. can you help to make this work with perl?

 cat a
a
b
c
d

 cat a |perl -lane 'printf("%s|",$_)' |perl -lane 's/|$//;print'
a|b|c|d|

 cat a |perl -lane 'printf("%s|",$_)' |sed 's/|$//'
a|b|c|d

Upvotes: 1

Views: 472

Answers (3)

ikegami
ikegami

Reputation: 385849

Why add then remove?

perl -pe'chomp; $_="|$_" if $. > 1; END { print "\n"; }'

By the way,

cat file | perl -e'...'   # Useless use of cat

can be written as

perl -e'...' <file

And since all solutions provided read from ARGV, you can even drop the redirection and pass the file name as an argument.

perl -e'...' file

For fun, golfing:

perl -pE'chomp;$.>1&&s/^/|/;END{say""}'  # Based on mine
perl -nlE'push@L,$_}{$"="|";say"@L"'     # Based on JRF's
perl -E'chomp(@L=<>);say join"|",@L'
perl -0777pe's/\n(?!\z)/|/g'

Only the first wastes no memory. The last one is probably the fastest.

Upvotes: 5

JRFerguson
JRFerguson

Reputation: 7516

join makes this trivial. You could do:

cat a | perl -lne'push @lines,$_;END{print join "|", @lines}'

...but then you get the useless cat award, so reduce that to:

perl -lne'push @lines,$_;END{print join "|", @lines}' a

a|b|c|d

Upvotes: 4

squiguy
squiguy

Reputation: 33370

Try escaping it,

cat a |perl -lane 'printf("%s|",$_)' |perl -lane 's/\|$//;print'

Perl sees | as an or in a search-and-replace.

Upvotes: 2

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