Extract multiple data from long string

Question

I am working in Crystal Reports XI looking at an SQL database. How can I pick up several different data bits from a realy long string? Each element I want is preceded by "Old Value =" or "New Value =". The problem is that there are up to 4 different sets of these "Old Value =", "New Value =" so I can only get the first set if I use "InStr" to find "Old Value =" or "New Value =".
Since they are preceded by unique headings like "RuntimeMinutes", I thought I could use "InStr" to find that "RuntimeMinutes" or whichever and then use that value as the location number nested in another "InStr" to find "New Value =" and nest it all in a "Mid" expression. But however I did it I got an error highlighting that "InStr" nested in "InStr" saying it was not an integer or the value was less than 1.
Any ideas?

Answer 1

The way that I'd deal with this is by creating formula fields for each value that you want to extract.  In the sample below, I'm assuming your string looks something like this:
RuntimeMinutes OldValue=123 NewValue=234 DbReads OldValue=12345 NewValue=34567
The formula for {@Runtime Minutes Old Value} would then look like (basic syntax):
dim pos as number
' Find where RuntimeMunutes old and new values start:
pos = InStr({really long string}, "RuntimeMinutes")
' Find first OldValue after RuntimeMinutes:
pos = InStr(pos + 14, {really long string}, "OldValue")  ' 14 = Len("RuntimeMinutes")
' Pull out the value:
formula = val(mid({really long string}, pos + 9,
                    Instr(pos + 9, {really long string}, " ") - pos - 9)) ' 9=Len("OldValue=")
And do the same for all of the other values you need. 
HTH,
Carl