Faced with Null/blank/empty value

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

Hi,
This is my script to capture some info as below:

$$ref_entry{$1} = $2 if /^([\w ]+?)\s+:.(\d+)/;
$$ref_entry{$1} = $2 if /^([\w ]+?)\s+:.'(.*)'/;
$$ref_entry{$1} = $2 if /^([\w ]+?)\s+:.>(.*)</;
print "TEST   $1 ==> $2\n";
[download]

Info is here:

Location Identity        : >0085 2f5b<     132321312
Required Bearer Capability  : ><
[download]

I'm would be faced a problem when any items is null or blank or empty, as example on the "Required Bearer Capability" items as above. How could I faced it ?

Any ideas ?....

20030722 Edit by Corion: Removed PRE tags, added formatting

Comment on Faced with Null/blank/empty value Select or Download Code

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Re: Faced with Null/blank/empty value by cLive ;-) (Prior) on Jul 22, 2003 at 08:35 UTC
I may be wrong here, but it looks like you're only looking for one of these to match. If so, why not do this: `/^([\w ]+?)\s+:.(\d+)/ or /^([\w ]+?)\s+:.'(.)'/ or /^([\w ]+?)\s+:.>(.)</ or /^([\w ]+?)(.*?)/ # no value or next; # I'm assuming this is in a loop somewher +e $$ref_entry{$1} = $2 \|\| 'default value here'; print "TEST $1 ==> $2\n";` [download] .02 cLive ;-)	[reply] [d/l]
Re: Re: Faced with Null/blank/empty value by jsprat (Curate) on Jul 22, 2003 at 08:58 UTC
Good idea - especially if it is in a loop. Instead of all three regexes every time, it'll do a maximum of 3. In order to get the same results, however, the three regexes need to be reversed. In bh_perl's example, when the first match and the last match succeeded, $1 and $2 are set in the third match. In your example, if the first match succeeds the third is never evaluated so $1 and $2 are set by the first match. Reverse the three matches and the results will match the OP's.	[reply]
Re: Faced with Null/blank/empty value by cLive ;-) (Prior) on Jul 22, 2003 at 09:07 UTC
I assumed that only one match was required and that bh_perl was just a little inexperienced here in coding that idea. If you look, the 3 regular expressions are exclusive - ie, if one matches, the other two won't. cLive ;-)	[reply]
Re: Re: Faced with Null/blank/empty value by jsprat (Curate) on Jul 22, 2003 at 09:45 UTC
Re: Faced with Null/blank/empty value by TomDLux (Vicar) on Jul 22, 2003 at 07:56 UTC
Use some default value. How about zero or the empty string or 'N/A'? You're the only one who knows what these values mean, so you'll have to figure out what an appropriate default value might be. You might use a `default()` routine: `sub default { return 0 unless( @_ && length $_[0] ); return $_[0]; } $$ref_entry{$1} = default( $2 ) if /^(\w +?)\s+:.(\d+)/; $$ref_entry{$1} = default( $2 ) if /^(\w +?)\s+:.'(.)'/; $$ref_entry{$1} = default( $2 ) if /^(\w +?)\s+:.>(.)</` [download] -- `TTTATCGGTCGTTATATAGATGTTTGCA`	[reply] [d/l]