CODEWITHSUNDEEP
perldictionaryindexingincrement
lmocsi
lmocsi

Reputation: 1096

How do I use an incremented index in Perl's map function?


I'd like to use an incremented index in Perl, in the map function. The code I have is:

use strict;

my $ord = "46.15,18.59,47.45,21.14";
my $c = 1;

my @a = split(",",$ord);
my $str = join("\n", map "x($c++) := $_;", @a);
print $str;

This outputs:

x(1++) := 46.15;
x(1++) := 18.59;
x(1++) := 47.45;
x(1++) := 21.14;

Instead of the x(1++), I would like x(1), x(2), etc.
How can I reach it?

Upvotes: 1

Views: 962

Answers (3)

ysth
ysth

Reputation: 98398

Instead of mapping the array, you can map your count, and not need a separate variable:

my $str = join("\n", map "x($_) := $a[$_-1];", 1..@a);

Or, to include a trailing newline:

my $str = join('', map "x($_) := $a[$_-1];\n", 1..@a);

Upvotes: 6

ikegami
ikegami

Reputation: 386331

Your problem has nothing to do with map. You placed Perl code inside a string literal and hoped it would get executed.

Replace

map "x($c++) := $_;",

with

map { ++$c; "x($c) := $_;" }

Also, you are missing a trailing newline. Fixed:

my $str = join "", map { ++$c; "x($c) := $_;\n" } @a;
print $str;

or

print map { ++$c; "x($c) := $_;\n" } @a;

Upvotes: 5

lmocsi
lmocsi

Reputation: 1096

It seems, that concatenating is the answer:

my $str = join("\n", map "x(".$c++.") := $_;", @a);

Upvotes: 0

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