print vs push?

McMahon has asked for the wisdom of the Perl Monks concerning the following question:

Hello monks...

I have some code that does List::Compare on the contents of two files. I realized, though, that there's no reason why I couldn't create the second array in memory and save myself having to write a second file to disk. However, these statements don't seem to produce the same array:

open COMP, "+>$file"; 

print COMP "$var1\n";
push @comp, "$var1\n";
<some stuff>
print COMP "\t$var2\n";
push @comp, "\t$var2\n";

my @array = <COMP>
[download]

when it's all finished,

 
@array ne @comp
[download]

...and that just doesn't seem right. I'd like to understand what's going on here. I hope I've provided enough code.

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Re: print vs push? by Roy Johnson (Monsignor) on Aug 20, 2004 at 15:46 UTC
Before you read from the file you've been writing to, you need to `seek COMP, 0, 0` Caution: Contents may have been coded under pressure.	[reply] [d/l]
Re: print vs push? by Fletch (Bishop) on Aug 20, 2004 at 15:46 UTC
Unless you `seek()` back to the beginning `@array` will be empty since `COMP` will be sitting at the end of the file.	[reply] [d/l] [select]
Re: print vs push? by lhoward (Vicar) on Aug 20, 2004 at 15:47 UTC
You need to reset the file pointer to BOF before reading in COMP. You can do that with seek (if you opened the file in read/write mode to begin with), or closed and re-opened the file in read mode. L	[reply]