Beefy Boxes and Bandwidth Generously Provided by pair Networks
No such thing as a small change
 
PerlMonks  

Re: Test if multiple variables are defined

by AnomalousMonk (Canon)
on Jun 25, 2013 at 17:50 UTC ( #1040636=note: print w/replies, xml ) Need Help??


in reply to Test if multiple variables are defined

One More Way to Do It: grep:

>perl -wMstrict -le "my ($foo, $bar); my ($no_ws, $some_ws, $lotsa_ws) = ('no_ws', ' some_ws ', ' lotsa ws '); printf qq{'$_' } for $no_ws, $some_ws, $lotsa_ws; print ''; ;; s{ \A \s+ | \s+ \z }''xmsg for grep defined, $no_ws, $foo, $some_ws, $bar, $lotsa_ws; printf qq{'$_' } for $no_ws, $some_ws, $lotsa_ws; " 'no_ws' ' some_ws ' ' lotsa ws ' 'no_ws' 'some_ws' 'lotsa ws'

Update: However,  grep as used above has the disadvantage of creating an output list that may be the same size as the input list; Perl then has twice as much data to deal with.

The advantage of a looping statement like
    defined and s/^\s+|\s+$//g for LIST;
is that the elements of  LIST are operated on in place and no new list is created.

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://1040636]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others musing on the Monastery: (14)
As of 2016-09-26 14:44 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?
    Extraterrestrials haven't visited the Earth yet because:







    Results (483 votes). Check out past polls.