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REGULAR EXPRESSIONS - extracting data from a file

REGULAR EXPRESSIONS - extracting data from a file

REGULAR EXPRESSIONS - extracting data from a file

I am trying to extract information from a file. I am trying to match the line but I don't understand all the [/\s+ stuff. Is there a place I can get a simple list of what all the functions do.

What I am actually trying to do is extract the number from a line which looks like

NET "clk" PERIOD = 9ns ;

RE: REGULAR EXPRESSIONS - extracting data from a file

short answer first.....how to match a number in a string.

While this stuff can get very concise, for clarity, I will be a little verbose.

$string = 'NET "clk" PERIOD = 9ns';
$string =~ /\d+/;    # matches the first set of digits found in the string
$number = $&;     # $& contains the matched value

if you want to be a little more selective about what you match.....

$string = 'NET "clk" PERIOD = 9ns';
$string =~ /NET "clk" PERIOD = (\d+)ns/;    # catch the digits in $1
$number = $1;     # $1 contains the value matched in the first set of paren's.

For Perl RegEx stuff
The O'Reilly "Programming Perl" book has the functional basics
 "Mastering Regular Expressions" by Jeffrey E.F. Friedl,Andy Oram (Editor) also from O'Reilly & Associates goes into excruciating detail.


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