Regex vs Instr

General
1 
x=( INSTR( mystring,"X") > 0 )

returns true or false if “X” is in mystring or not…

what I need (and I know RegEx can do it, I just can’t get around RegEx syntax)

x=DoesContain(mystring,"WXYZ")

which returns true or false if mystring contains ANY of the characters “W”,“X”,“Y” or “Z”

2

[WXYZ]

[ ] in a regex means “in this set”

http://documentation.xojo.com/index.php/RegEx
[a-z0-9] Matches any single character of set.

3 
Public Function DoesContain(source as string,find as string) as boolean
  Dim rg As New RegEx
  // need to escape "find" string in some cases
  rg.SearchPattern = "["+find+"]"
  return (rg.Search(source)<>Nil)
End Function
4

Or…

word|W|X|Y|Z

Rather than using a set which will check for ONLY those characters. The above construct will search for “word”, “W”, “X”, “Y” or “Z”.

5

[quote=338458:@Norman Palardy][WXYZ]

in a regex means “in this set”

http://documentation.xojo.com/index.php/RegEx
[a-z0-9] Matches any single character of set.[/quote]

Yer welcome dave

6

Remember too that RegEx can be case sensitive or case insensitive. You control that by assigning RegExOptons .

You can also do a pattern like [WXYZwxyz]

7

Be careful with this. If your set contains a closing bracket, hyphen, or backslash, you’ll have to escape those.

8

The thick plottens!

9

and if this is to parse the sql in your database app, then regex will be mandatory at some time soon…
Instr will never be enough.

10

[quote=338471:@Jean-Yves Pochez]and if this is to parse the sql in your database app, then regex will be mandatory at some time soon…
Instr will never be enough.[/quote]
neither regex or instr is a tokenizer &/or parser which is really the right thing to have to recognize & handle a language
but thats way off this topic

11

and not to worry, I have previously developed a very fast and very powerful “tokenizer” that I have used not only in Tadpole, but in various interpeter and compiler projects I have worked on over the years… And yes I know there is a difference between a tokenizer and a parser… A tokenizer determines characters that belong to a word, phrase or quoted string, while a parser would determine the meaning or relation of those tokens to an end result :slight_smile:

12

[quote=338461:@Dave S] Public Function DoesContain(source as string,find as string) as boolean Dim rg As New RegEx // need to escape "find" string in some cases rg.SearchPattern = "["+find+"]" return (rg.Search(source)<>Nil) End Function [/quote]

Seems like a great function, but its returning true for everything I throw at it. Am I not understanding the purpose. I thought it was to see if a string existed inside another. If so return true else false.

13

No… if you want to find if a string exists inside another string that is what the INSTR function is for…
What I wanted, was to find is ANY one of a series of characters existing in a string"

DoesContain("ABCDEFGHI","ZQIX")=true // BOTH strings contain the letter "I"

to do that with Instr would be

If Instr("ABCDEFGHI","Z")=true or _
 Instr("ABCDEFGHI","Q")=true or _
 Instr("ABCDEFGHI","I")=true or _
 Instr("ABCDEFGHI","X")=true then
14

[quote=338749:@Dave S]No… if you want to find if a string exists inside another string that is what the INSTR function is for…
What I wanted, was to find is ANY one of a series of characters existing in a string"

DoesContain("ABC","Z")=false DoesContain("ABCDEFGHI","ZQIX")=true // BOTH strings contain the letter "I" [/quote]

Gotcha, thanks.