Perl 101 (Part 4) - Mind Games - Different Strokes

(Page 3 of 10 )

There's also another method of reading data from a file - a loop that will run through the file, printing one line after another:

---

#!/usr/bin/perl
# open file and define a handle for it
open(MIND,"thoughts.txt");
# assign the first line to a variable
$line = <MIND>;
# use a loop to keep reading the file
# until it reaches the end
while ($line ne "")
{
print $line;
$line = <MIND>;
}
# close file when done
close(MIND);
# display message when done
print "Done!\n";

---

Well, it works - but how about making it a little more efficient? Instead of reading a file line by line, Perl also allows you to suck the entire thing straight into your program via an array variable - much faster, and definitely more likely to impress the girls!

Here's how:

---

#!/usr/bin/perl
#pen file and define a handle for it
open(MIND,"thoughts.txt");
# suck the file into an array
@file = <MIND>;
# close file when done
close(MIND);
# use a loop to keep reading the file
# until it reaches the end
foreach $line (@file)
{
print $line;
}
# display message when done
print "Done!\n";

---

As you can see, we've assigned the contents of the file "thoughts.txt" to the array variable @file via the file handle. Each element of the array variable now corresponds to a single line from the file. Once this has been done, it's a simple matter to run through the array and display its contents with the "foreach" loop.

This article copyright Melonfire 2000. All rights reserved.

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