Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!samsung!sol.ctr.columbia.edu!lll-winken!uunet!pmafire!uudell!bigtex!texsun!convex!convex.COM
From: tchrist@convex.COM (Tom Christiansen)
Newsgroups: comp.lang.perl
Subject: Re: Arrays and me :-(
Message-ID: <110866@convex.convex.com>
Date: 12 Dec 90 19:19:40 GMT
References: <29144@sequoia.execu.com> <484@decvax.decvax.dec.com.UUCP>
Sender: usenet@convex.com
Reply-To: tchrist@convex.COM (Tom Christiansen)
Distribution: usa
Organization: CONVEX Software Development, Richardson, TX
Lines: 42

In article <484@decvax.decvax.dec.com.UUCP> evans@decvax.DEC.COM writes:
:In article <29144@sequoia.execu.com>, painter@sequoia.execu.com (Tom Painter) writes:
:|> 
:|> I'd like to split a passwd file into a multi-dimensional array.  
:How about the following:

Yes, that works.

:	# read all of the file into the @lines array
:	open(PASSWD,"/etc/passwd");
:	push(@lines,$_) while (<PASSWD>);

	@lines = <PASSWD>
is faster.

:	close(PASSWD);
:
:	# print the 5 field of the 50th entry
:	printf "%s\n", &get_field($lines[50],5);
:
:	# subroutine which decomposes : seperated lines
:	sub get_field
:	{   local($line,$field) = @_;
:	    local(@fields) = split(/:/,$line);
:	    return(($#fields >= $field) ? $fields[$field] : "");
:	}

If you deference past the end of the array, you get null anyway.
You could actually just make this:

    sub get_field { (split(/:/,$_[0]))[$_[1]]; } 

Or else inline it.

But those are just speed optimizations, and they don't
make all *that* much difference.

--tom
--
Tom Christiansen		tchrist@convex.com	convex!tchrist
"With a kernel dive, all things are possible, but it sure makes it hard
 to look at yourself in the mirror the next morning."  -me