Use $rexexp() in column?

I'm trying to remove everything in the %BPM% field (which for example contains "00319 BPM") except "319"

Currently the value field in the bpm column contains "$regexp(%bpm%,([1-9]+),$)" (without the quotes of course)

But it's printing a long error message about the + operator.

"$regexp(%bpm%,[1-9]+,$0)"

But there is still a flaw. You only want to knock out the leading zeros. Don't you?

"$regexp(%bpm%,[1-9][0-9]*,$0)"

You do not need a regular expression, a simple standard function can help too ...

$num('00123 BPM',0) ==> '123' $num('00120 BPM',0) ==> '120' $num(%BPM%,0)

If you want a regular expression ...

$regexp(%BPM%,'0*(\d+).*','$1')

DD.20160325.1827.CET

Thanks @DetlevD the $num() function worked perfectly.

For anyone coming from Google the solution was: $num(%bpm%,)