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LotusScript: over 780% faster checking for empty strings

Canardian

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I read on planetlotus.org about Bob Balaban's test of the speed difference between s="" vs len(s)=0 checking ( http://www-10.lotus.com/ldd/bpmpblog.nsf/dx/performance-testing-technique ).My test agent looks like this:Sub Initialize Dim n As Long, ni As Long n=10 ' number of test repeats Dim t1 As Double, t2 As Double, tn As Double, tt As Double Dim i As Integer, j As Integer, k As Long Const x=10000 Const s="xxxxxxxxxx" For ni=1 To n t1=Timer For i=1 To x For j=1 To x k=Len(s)=0 Next Next t2=Timer tn=t2-t1 tt=tt+tn Print ni & ": " & Format(tn,"00000.00000") & "s." Next Print "Average: " & tt / n & "s."End SubThe line with k=Len(s)=0 varied and gave the following average timings over 10 tests:<font size="1">Const s=""<font size="1">k=Len(s)=0<font size="1">7.532s<font size="1">Const s=""<font size="1">k=s""<font size="1">58.938s<font size="1">Const s="xxxxxxxxxx"<font size="1">k=Len(s)=0<font size="1">7.688s<font size="1">Const s="xxxxxxxxxx"<font size="1">k=s""<font size="1">63.089s<font size="1">Const s="xxxxxxxxxx"<font size="1">k=s=""<font size="1">65.770sThat means, even with small loops like 1 billion iterations, you get almost a minute faster results! Anyway, the number of iterations is not so important and you can't really judge on that, as someone might need even bigger iterations, but the fact that it's over 780% faster to use len(s) is important.I don't think it's concidence that several people started to blog about LotusScript performance practices, just after I started to think about revising the LotusSphere 2007 LotusScript speed presentation, even before I posted anything on my blog. I think there is somekind of shared mind, which we can't explain scientifically yet.

 

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