OpenEuphoria

Re: match() in depth!

• Posted by Derek Parnell <ddparnell at bigpond.com> Feb 24, 2002
• 405 views

Hi Kat,

however the result of parse() is a nested sequence.

IOW this ==> {"this","is","a","test","of","match()"} is a sequence that
 contains six other
sequences (aka strings). And match is actually looking for matching slices. When
we are dealing with
sequences that look like strings, we can easily think of match as looking for
substrings. But in
Euphoria palance, a substring is just a slice of a sequence.

If we use some symbolic representation of the test sequence above it could be
coded as :

 {TIAtOM} 

where I've simple replaced each word with a letter representing that word.

Thus the find for "is" similarly coded is match({I}, test). This will return 2.
The scan for the
"s" word is coded match({S},test) and returns 0 because there is no "s" word in
the test sequence.

May I recommend trying to locate "is" word in a standard Euphoria sequence
string by doing :

find (" is ", test) -- Note the spaces around the word. This might save you
   parsing it too often.



25/02/2002 3:23:51 PM, Kat <gertie at PELL.NET> wrote:

>
>On 25 Feb 2002, at 14:01, Derek Parnell wrote:
>
>> 
>> Hi Kat,
>> I'm not quite sure what you are driving at either.
>> 
>> When you run this code of yours, what do you get displayed?
>> 
>> When I run it, it only reports that 'is' is found. And this is exactly what I
>> would have expected.
>> 
>> My assumption is that 'parse()' converts :
>> 
>>  "this is a test of match()"
>> 
>> to:
>> 
>>  {"this","is","a","test","of","match()"}
>
>Correct.
> 
>> In which case the match({"is"},test) call will return 2. Because "is" is the
>> second element of the test sequence.
>
>> In which case the match({"s"},test) call will return 0. Because "s" is not
>> any
>> of the elements in the test sequence.
>> 
>> What did you find surprising with your test?
>
>I had never seen the match({"is"},test) in any code i have read in the 
>archives. I have seen match("is",test). Frankly, the use of {} occasionally 
>confuses me, and to put the "is" inside the { } told me it was a nested 
>sequence, and should have returned nothing, zero, or an error,, because the 
>help files say all the parms for match() are to be sequences, and a nested 
>seq as the first parm barely makes sence. But i was looking for a way to get 
>some code running faster, and tried it.
>
>Kat
>
>
>> ------
>> Derek.
>> 
>> 
>> 25/02/2002 1:43:42 PM, Kat <gertie at PELL.NET> wrote:
>> 
>> >
>> >On 24 Feb 2002, at 22:52, rforno at tutopia.com wrote:
>> >
>> >> 
>> >> OK. But what is the strange thing about it? I don't understand.
>> >
>> >The {bracketed} and "quoted" parts in the examples below. 
>> >
>> >Kat
>> >
>> > 
>> >> ----- Original Message ----- 
>> >> From: "Kat" <gertie at PELL.NET> 
>> >> To: "EUforum" <EUforum at topica.com>
>> >> Sent: Sunday, February 24, 2002 12:49 AM
>> >> Subject: match() in depth!
>> >> 
>> >> 
>> >> > I didn't know we could do this!
>> >> > 
>> >> > include strtok.e
>> >> > with trace
>> >> > sequence test
>> >> > 
>> >> > test = "this is a test of match()"
>> >> > test = parse(test,32)
>> >> > 
>> >> > 
>> >> > if match({"is"},test) then 
>> >> >  puts(1,"found is\n") 
>> >> > end if
>> >> > 
>> >> > if match({"s"},test) then 
>> >> >  puts(1,"found s\n") 
>> >> > end if
>> >> > 
>> >> > trace(1)
>> >> > abort(0)
>> >> > 
>> >> > 
>> ---------
>> Cheers,
>> Derek Parnell 
>> 
>> 
>
>
>
---------
Cheers,
Derek Parnell