When using IndexOf with StartingIndex can it repeat StartingIndex

General
1

I am building a list of locations for a word in a string with the While loop below.
When using IndexOf with StartingIndex can it repeat StartingIndex?
That is what I am finding. I have one place in the string it is at (19) and it finds it the first time, and then I have an endless loop.

Var ptr As Integer = 0 Var cnt As Integer = 0 While ptr > -1 ptr = TextBx.Value.IndexOf(ptr, LSrchWord)// Plces.AddRow ptr wend

TextBx is the TextArea
LSrchWord is the search string
Plces is an array of integers

2

How about:

var ptr  as integer = TextBx.Value.IndexOf( LSrchWord )
while ptr <> -1
  Places.AddRow ptr
  ptr = TextBx.Value.IndexOf( ptr + LSrchWord.Length, LSrchWord )
wend

(Untested.)

3

Thanks. I’ll try that.

I assume including StartingIndex means the next value in the array has to be a higher value.
With InStr it does mean it has to be another value.
I know because I used InStr here before IndexOf.
Correct?

I also assume it means it will not recycle, but it does?

4

The first use does not include it, and your code never increments it, hence it “recycles”.

5

I did but without an incrementer.

ptr = TextBx.Value.IndexOf(ptr, LSrchWord)

Grumble. There is no example of it using Start in the LR.
Grumble. I think I’ve been spoiled by XOJO. I actually thought it took care of the increment.

I also like the way you start the while with

Plces.AddRow ptr
6

Think of it this way. Var Pos As Integer = “abcd”.IndexOf(“a”) This code will not work, it’s just for demonstration. In this case Pos will be 0 because what is returned is the index of the desired character. Think of it as “0 characters were skipped before the a was found.”

When you try IndexOf(0, “a”) you still get back zero because you told Xojo “skip the first 0 characters, then start searching for a.”

With InStr, the returned value was 1-based. This twists the logic a little. No longer does the phrase “1 character was skipped before the a was found” work because it’s not true. The result means “the a was found as the first character.” It also means when you use the start parameter, the request is “skip the first character, then start searching for a.” In a sense, your goal happened because InStr returns a 1-based value, but the start position takes a 0-based value. So you kind of got that built-in incrementing effect.

7

Thanks for the explanation. I had to drop out of the college Logic class because of this sort of stuff.