i had a need of a routine to do the opposite of INSTR( in which I wanted to find the last appearance of a search field in the target string. So I wrote the following functions:
- ' Reverse instr: finds last position of search in target
Function Rinstr& (Target As String, Search As String)
- ' Case insensitive search
Function Iinstr& (start As Long, Target As String, Search As String)
- ' Case insensitive reverse seaarch
Function RIinstr& (Target As String, Search As String)
I'm not sure how useful this would be, but I suspect someone is going to need one of these at some point.
The functions include a program that runs a set of tests to confirm they work.
Glad to see I'm not the only one who is Wikilliterate around here. Anyway, kudos for writing your own version. I dd the same several years back, before _INSTRREV came along. It's a big help for word wrap in WP apps. I had a bit of a go-around with Fell when _INSTRREV first came out, regarding the seed parameter. _INSTRREV keeps the same forward seed counting as INSTR. There are reasons for that, which slip my mind at the moment, but I do recall I made an easy workaround, so it could seed backwards. Compare these two...
Code: (Select All)
For i = 1 To 8
Print i; _InStrRev(i, "12*456*8", "*")
Next
For i = 1 To 8
Print i; _InStrRev(Len("12*456*8") - i + 1, "12*456*8", "*")
Next
Pete
@Pete The reason is for easy splitting of the string.
a$ = "C:\My Dir\My File.txt"
Now, get the last slash in that string, to break it down to path + file:
path$ = LEFT$(a$, _INSTRREV(a$, "\"))
file$ = MID$(a$, _INSTRREV(a$, "\") + 1)
But your example is SEEDLESS. Great if you're growing grapes, but let's not
wine about it...
Code: (Select All)
' 1111111111222222222233333333
'1234567890123456789012345678901234567
'c:\root\mystuff\basic\qb64\myfile.bas
file$ = "c:\root\mystuff\basic\qb64\myfile.bas"
seed% = 1
Do
next_to_last$ = Mid$(file$, _InStrRev(Len(file$) - seed%, file$, "\") + 1)
Print seed%, next_to_last$
seed% = Len(next_to_last$) + 1
Loop Until seed% > Len(file$)
Print
seed% = Len(file$)
Do
next_to_last$ = Mid$(file$, _InStrRev(seed%, file$, "\") + 1)
Print seed%, next_to_last$
seed% = _InStrRev(seed%, file$, "\") - 1
Loop Until seed% < 0
End
So a couple of chop methods, but my initial contention was when we count in reverse, we should seed in reverse. I let that go, because there is at least a since of continuity that even though the searching part of the string has been reversed, the seeding order, from beginning to end, remains constant.
Pete
Here are some custom Instr functions.
The first as a string comparison, the second a filename comparison.
The string one allows * and ? where the second one has *, ?, ^ comparison.
Erik.
