A while loop over a filehandle like while(my $line = <$fh>) { ... } reads the file line-by-line* (one line is read on each iteration of the loop), as opposed to foreach my $line (<$fh>) { ... } or my @lines = <$fh>;, which reads the entire file first (obviously not particularly friendly on memory for large inputs).

For more information, see I/O Operators in perlop and readline.

* Perl's definition of what a "line" is may be changed via the input record separator $/.

... since I only work with CSV files.

Text::CSV!

I will definitely look into the Text::CSV module...

Yes! ;-)

In reply to Re^3: Find data point generating Error in Perl code by Anonymous Monk
in thread Find data point generating Error in Perl code by kgherman

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