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');

[download]

OUTPUT:

1..1
ok 1 - concatenation

[download]
Bill

In reply to Re: file open with variables by BillKSmith
in thread file open with variables by Anonymous Monk

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