You want to include a list in your program. This is how you initialize arrays.
You can write out a comma-separated list of elements:
@a = ("quick", "brown", "fox");
If you have a lot of single-word elements, use the qw( ) operator:
@a = qw(Meddle not in the affairs of wizards.);
If you have a lot of multiword elements, use a here document and extract lines:
@lines = (<< "END_OF_HERE_DOC" =~ /^\s*(.+)/gm); I sit beside the fire and think of all that I have seen, of meadow-flowers and butterflies and summers that have been; END_OF_HERE_DOC
The first technique is the one most commonly used, often because only small arrays are normally initialized as program literals. Initializing a large array would fill your program with values and make it hard to read, so such arrays either tend to be initialized in a separate library file (see Chapter 12), or else have their values read in from a file:
@bigarray = ( ); open(FH, "<", "myinfo") or die "Couldn't open myinfo: $!"; while (<FH>) { chomp; push(@bigarray, $_); } close(FH);
The second technique uses qw( ), one of several pseudo-functions in Perl used for quoting without having to resort to actual quotation marks. This one splits its string argument on whitespace to produce a list of words, where "words" in this instance means strings that don't contain any whitespace. The initial argument is not subject to interpolation of variables or (most) backslash escape sequences.
@banner = ('Costs', 'only', '$4.95'); @banner = qw(Costs only $4.95); @banner = split(' ', 'Costs only $4.95');
You can use qw( ) only when each whitespace-separated argument is to be a distinct element in the return list. Be careful not to give Columbus four ships instead of three:
@ships = qw(Niña Pinta Santa María); # WRONG @ships = ('Niña', 'Pinta', 'Santa María'); # right
The third solution takes a here document, which is a single, multiline string, and applies a global pattern match to that string. The pattern /^\s*(.+)/ says to skip any whitespace at the start of the line, then capture everything through the end of each line. The /g modifier means to apply that match globally, and the /m modifier says to permit ^ to match not just at the beginning of the string, but also immediately after a newline, which, in a multiline string, is just what you need. Applying that technique to the ships example yields:
@ships = ( << "END_OF_FLOTILLA" =~ /^\s*(.+)/gm); Niña Pinta Santa María END_OF_FLOTILLA
The "List Value Constructors" section of perldata(1); the "List Values and Arrays" section of Chapter 2 of Programming Perl; the "Quote and Quote-Like Operators" section of perlop(1); the s/// operator in perlop(1) and Chapter 5 of Programming Perl
| 4. Arrays | 4.2. Printing a List with Commas |
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