EViews.com

Posted: **Wed Feb 16, 2011 10:30 am**

Hey Guys, how are you?

I have this string with non-unique elements in it, and I need to find out the positions of a particular element:
e.g.,

Code: Select all

%names = "John Paul Andrew John John Tom"

Let's say I want to find out the positions of all the "John" in this string. I know with @wfind you can find out the position of the first one (in this case, 1), but is there an easy way where Eviews can tell me the answer "1 4 5" in one shot? I have thought about putting %names into a svec but then I feel that it's a bit cumbersome. If I do @instr(%name, "John"), it only gives me the position of where the first "John" starts. Would you please let me know your thoughts on this? Thanks.

Tchaithonov

Posted: **Wed Feb 16, 2011 12:16 pm**

I can't think of an easy way since the word seeking functions only search for a single instance. Here's a bit of a hack which calls the word seeking function recursively, lopping off parts of a copy of the string as it goes. It returns the result in the form of a string of elements. If you want it as a numeric vector we can make a quick change to the subroutine. Let me know. Note also that I do the comparison as a case-sensitive @wfind. You can change this to a non-case sensitive @wfindc if you wish.

I've run a couple of quick tests and it looks okay, but you should do a bit of shakeout before using it for anything serious.

Here's the subroutine...

Code: Select all

subroutine local wfindall(string result, string src, string target)

string srctemp = src
result = "" ' initialize

' initialize recursion
!found = 0
!posit= 0
!try = @wfind(srctemp, target) ' get the first match

' recursive loop
while (!try <> 0)
	!found = !found + 1
	result = result + " " + @str(!try + !posit) ' accumulate the result
	srctemp =  @wmid(srctemp, !try+1) ' get the remainder string
	!posit= !posit + !try ' increment the number of trimmed
	!try = @wfind(srctemp, target) ' look for the next
wend
	
result = @trim(result) ' cleanup

endsub

and an example of calling it

Code: Select all

string result
call wfindall(result, %names, "John")

As I said, if you want this as a numeric vector, it's a quick modification.

Posted: **Wed Feb 16, 2011 1:44 pm**

Hi Glenn,

That's great. I think it serves the purpose I am looking for. Thanks.

Tchaithonov

EViews.com

matching strings

matching strings

Re: matching strings

Re: matching strings