regexp problem - extract all but last part of SNMP OID

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

Hi. I need to process some SNMP OIDs of the form 1.3.6.1.4.1.1012.4.1 (variable length) and get me everything except the last number. for instance:

print "oid[$oidfila]\n" 

oid[1.3.6.1.4.1.1012.170.2.40.1.1.1.0.4194288]
[download]

I need to extract the 4194288 from $oidfila and get me the rest... I've tried:

$oidfila  =~ s/^[0-9\.]+(\.[0-9]+)$//;
[download]

but it just gets me blanks. You help is more than appreciated. Regards, Leo

Comment on regexp problem - extract all but last part of SNMP OID Select or Download Code

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Re: regexp problem - extract all but last part of SNMP OID by Eliya (Vicar) on Nov 21, 2011 at 16:23 UTC
`$oidfila =~ s/^[0-9\.]+(\.[0-9]+)$//;` [download] This is already a good start, but you're matching - and thus substituting - too much. Leave off the first part and things will be ok: `$oidfila =~ s/\.[0-9]+$//;` [download]	[reply] [d/l] [select]
Re^2: regexp problem - extract all but last part of SNMP OID by kennethk (Abbot) on Nov 21, 2011 at 17:06 UTC
Alternatively, if the initial condition is essential, you can use a capture on the lead in. This is inefficient, but necessary without variable-length look behind support. `$oidfila =~ s/(^[0-9\.]+)\.[0-9]+$/$1/;`	[reply] [d/l]
Re^3: regexp problem - extract all but last part of SNMP OID by hbm (Hermit) on Nov 21, 2011 at 19:18 UTC
Which, according to perlre, can be written more efficiently with the "keep" construct: `$oidfila =~ s/^[\d.]+\K\.\d+$//;` [download]	[reply] [d/l]