| quick testing of string variables [message #6124] |
Tue, 23 April 1996 00:00  |
moninger
Messages: 2
Registered: March 1995
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Junior Member |
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I have an array called station_name, dimensioned (6,n). Each item is a
string 6 characters long. I would like to quickly test station_name
against a particular string variable, find_this_station, another string of
dimension 6.
Is there any way to do this without using loops?
If I have to use loops, does anyone have a tip on the fastest way to do so?
Is there are better way to configure the array station_name to make such
tests (against a particular station name) faster?
I shall appreciate any help anyone can provide.
-Bill Moninger
--
Bill Moninger, NOAA/Forecast Systems Laboratory.
home: 303-494-1709, work: 303-497-6435
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| Re: quick testing of string variables [message #6194 is a reply to message #6124] |
Sun, 28 April 1996 00:00  |
hamill
Messages: 4
Registered: April 1996
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Junior Member |
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The example below is fine. It is often convenient,and a good idea, to use
an additional argument to the WHERE function, since it returns the number
of matches found, i.e. t = WHERE(a EQ 's4',n) & IF n NE 0 THEN ... Use
of n is to my taste cleaner and easier to read.
This is my first posting to any newsgroup; so apologies if for some reason
it does not read well.
----------------------------
Jim Hamill
hamill@ais.net
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In article <DqBo3L.KL4@midway.uchicago.edu>, rivers@cars3.uchicago.edu wrote:
> In article <moninger-2304960900010001@zirkle.fsl.noaa.gov>,
moninger@fsl.noaa.gov (Bill Moninger) writes:
>> I have an array called station_name, dimensioned (6,n). Each item is a
>> string 6 characters long. I would like to quickly test station_name
>> against a particular string variable, find_this_station, another string of
>> dimension 6.
>>
>> Is there any way to do this without using loops?
>>
>> If I have to use loops, does anyone have a tip on the fastest way to do so?
>>
>> Is there are better way to configure the array station_name to make such
>> tests (against a particular station name) faster?
>
> Here is how to do it:
>
> IDL> a = ['s1', 's2', 's3', 's4', 's5', 's6']
> IDL> t = where(a eq 's4')
> IDL> print, t
> 3
>
> The where() function finds the index number of the string in the array which
> matches your test string. It returns -1 if there is no match.
>
> ____________________________________________________________
> Mark Rivers (312) 702-2279 (office)
> CARS (312) 702-9951 (secretary)
> Univ. of Chicago (312) 702-5454 (FAX)
> 5640 S. Ellis Ave. (708) 922-0499 (home)
> Chicago, IL 60637 rivers@cars3.uchicago.edu (Internet)
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