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Raknarg

Wed May 25, 2011 9:58 am


Index function

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Is there a string indexing function in VB like there is in Turing?


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Nick

Wed May 25, 2011 10:10 am


RE:Index function

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string.IndexOf ("pattern")


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2goto1

Wed May 25, 2011 10:11 am


RE:Index function

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There are quite a few more things you can with strings, http://msdn.microsoft.com/en-us/library/system.string.aspx


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Raknarg

Wed May 25, 2011 10:36 am


RE:Index function

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Ok then, one more question: What value does String.Compare return if the string isn't inside the other string? I tried 0, but it doesn't seem to work.


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2goto1

Wed May 25, 2011 12:24 pm


Re: Index function

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Compare returns an integer that indicates their relative position in the sort order, as mentioned at http://msdn.microsoft.com/en-us/library/84787k22.aspx

It tells you the alphabetical ordering of two strings. Here are some test cases that you can try:

[code]String.Compare("A", "B")[/code]  Returns -1 since A is alphabetically before B
[code]String.Compare("a", "B")[/code]  Returns -1 since a is alphabetically before B
[code]String.Compare("B", "A")[/code]  Returns 1 since B is alphabetically after A
[code]String.Compare("B", "B")[/code]  Returns 0 since B is alphabetically the same as B

Here?s where it can get confusing:
[code]String.Compare("B", "b") [/code] Returns 1 since although B is alphabetically the same as b, B?s character code is less than b
[code]String.Compare("b", "B")[/code]  Returns -1 since although b is alphabetically the same as B, b?s character code is greater than B

The API seems to differ once you start comparing the same letter, but different case. If your intent is to determine that b is alphabetically the same as B, then your best bet is to use this method:

[code]String.Compare("b", "B", true)[/code] Returns 0 - equivalent ignoring case

Where true means to ignore case. 

The same thing applies when comparing longer strings, i.e.: 

[code]String.Compare("Apple", "Apricot", true)[/code]  Returns -1 since apple is alphabetically before Apricot
[code]String.Compare("Apricot", "Apple", true)[/code]  Returns 1 since apricot is alphabetically before apple


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Raknarg

Wed May 25, 2011 3:05 pm


RE:Index function

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Oh, thanks, I was using it wrong.