On 19 Jul 2001, Keith Bradnam wrote:
> Any acedb query gurus out there who can help me with a problem?
>> It might be that it's beyond the capabilities of the acedb query language
> in which case Ed will set me straight.
>> How do you test for the absence of a value in a tag-value pair where you
> would normally expect a value?
...snip...
> Any ideas anyone? This would be really useful to me if it is possible.
That Keith Bradnam, he knows nothing! He should have tried using
AcePerl! ;)
Having given up on constructing an acedb query, I resorted to looking at
AcePerl. The following is a simple solution for the problem of finding
Homol tags which don't have any associated value.
my $db = Ace->connect(-path => 'path_to_database');
my @sequences = $db->fetch(-class => 'Sequence');
foreach my $sequence (@sequences){
if($sequence->Homol){
my ($value) = $sequence->at('Homol');
print "$sequence - No value!\n" if (!defined($value));
}
}
It gets messier if you have subtags to 'Homol' (such as 'Pep_homol') which
you might want to additionally check for the absence of a value. Feel
free to email me if anyone finds this stuff of use and wants to know more.
Keith
~ Keith Bradnam - WormBase group: http://wormbase.sanger.ac.uk/
~
~ The Sanger Centre, Wellcome Trust Genome Campus
~ Hinxton, Cambridge, CB10 1SA, UK. Tel (01223) 497516
