in reply to file open with variables

An alternate way to build a string (your file name) is to use the concatenation ('.') operator (refer: Additive Operators) rather than interpolation. In this case it has the advantage that you keep your single quotes and single backslashes. I have used Test::Simple to verify that I have constructed the string you expect. 
use strict;
use warnings;
use Test::Simple tests=>1;

# Expected
#
my $expected_file_name = 'D:\PROJ\N123_X3\dataInfo_X-4_Y5_decode.csv';


# Given

my $X_info =  3;
my $Y_info = -4;
my $Z_info =  5;


my $concatenated_name = 
      'D:\PROJ\N123_X'
    . $X_info               #  3
    . '\dataInfo_X'
    . $Y_info               # -4
    . '_Y'
    . $Z_info               #  5
    . '_decode.csv'
    ;

ok($concatenated_name eq $expected_file_name, 'concatenation');

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OUTPUT:

1..1
ok 1 - concatenation

[download]
Bill

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Re^2: file open with variables
by AnomalousMonk (Archbishop) on Sep 28, 2022 at 23:10 UTC

    An alternative to chained string concatenation is the join built-in. This has the advantage IMHO that it operates on a "pure" list, i.e., one that can be built | built arbitrarily from strings, arrays, function calls, etc. 

    Win8 Strawberry 5.8.9.5 (32)  Wed 09/28/2022 18:56:53
C:\@Work\Perl\monks
>perl

use strict;
use warnings;
use Test::Simple tests=>1;
1..1

# Expected
my $expected_file_name = 'D:\PROJ\N123_X3\dataInfo_X-4_Y5_decode.csv';

# Given
my $X_info =  3;
my $Y_info = -4;
my $Z_info =  5;

my @intro = ('D:\PROJ\N123_X', $X_info, '\dataInfo_X', $Y_info);

my $concatenated_name = join '',
    @intro, '_Y', $Z_info, '_decode.csv',
    ;

ok($concatenated_name eq $expected_file_name, 'join concatenation');

^Z
ok 1 - join concatenation

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