| Re: IDL- variable variable names [message #7360] |
Sun, 10 November 1996 00:00 |
alpha
Messages: 49
Registered: September 1996
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Member |
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davidf@fortnet.org (David Fanning) writes:
> I wrote in a previous article:
> Here is an obvious modification that I overlooked that nudges it
> even closer. And I added some help for the 8.3 crowd! :-)
yes... this ugly 8.3 guys.... sometimes they even 8.203 packets...
> FUNCTION MAGIC, file
> number = 0
> RESTORE, file + '.sav'
> RETURN, number
> END
> IDL> a = 10
> IDL> number = a
> IDL> Save, number, Filename='a.sav'
> IDL> b = 'a'
> IDL> c = Magic(b)
> IDL> IF c EQ 10 THEN Print, "It's magic!"
>
> It's magic!
> This almost borders on the useful now. What do you have
> in mind for this, Hendrik?
hmmm OK, it seems it does not suffer on the 131-problem!
i will do some meditation on that...
Panther (alias Hendrik)
--
Panther in the Jungle __..--''``\--....___ _..,_
-BELIEVE AND DECEIVE- _.-' .-/"; ` ``<._ ``-+'~=.
http://www.ang-physik _.-' _..--.'_ \ `(^) )
.uni-kiel.de/~hendrik ((..-' (< _ ;_..__ ; `'
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| Re: IDL- variable variable names [message #7361 is a reply to message #7360] |
Sun, 10 November 1996 00:00  |
meron
Messages: 51
Registered: July 1995
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Member |
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In article <davidf-ya023080000711961510130001@news.frii.com>, davidf@fortnet.org (David Fanning) writes:
> I wrote in a previous article:
>
>> But..., I got about this close:
>>
>> FUNCTION MAGIC, file
>> number = 0
>> ok = EXECUTE(file + ' = 0')
>> RESTORE, file
>> RETURN, number
>> END
>>
>> IDL> a = 10
>> IDL> number = a
>> IDL> Save, a, number, Filename='a'
>> IDL> b = 'a'
>> IDL> c = Magic(b)
>> IDL> IF c EQ 10 THEN Print, "It's magic!"
>>
>> It's magic!
>
> Here is an obvious modification that I overlooked that nudges it
> even closer. And I added some help for the 8.3 crowd! :-)
>
> FUNCTION MAGIC, file
> number = 0
> RESTORE, file + '.sav'
> RETURN, number
> END
>
> IDL> a = 10
> IDL> number = a
> IDL> Save, number, Filename='a.sav'
> IDL> b = 'a'
> IDL> c = Magic(b)
> IDL> IF c EQ 10 THEN Print, "It's magic!"
>
> It's magic!
>
> This almost borders on the useful now. What do you have
> in mind for this, Hendrik?
>
Oh, you can get useful stuff using EXECUTE, and there is no need to go
through saving and restoring. Here is an example
Function One_of, v_0, v_1, v_2, v_3, v_4, v_5, v_6, v_7, value = val
;+
; NAME:
; ONE_OF
; PURPOSE:
; Called with up to 8 variables V_0 through V_7 , ONE_OF checks which
; variable is defined (only one is supposed to be).
; CATEGORY:
; Programming.
; CALLING SEQUENCE:
; Result = ONE_OF( V_0 [,V_1, ... V_7] [, VALUE = VAL])
; INPUTS:
; V_0 through V_7
; Arbitrary, all are optional.
; OPTIONAL INPUT PARAMETERS:
; See above.
; KEYWORD PARAMETERS:
; VALUE
; Optional output, see below.
; OUTPUTS:
; Returns the serial number (range 0 through 7) of the defined variable,
; or -1 if none is defined. If more than one variable is defined, ONE_OF
; issues an error message and returns to the main level.
; OPTIONAL OUTPUT PARAMETERS:
; VALUE
; The name of the variable to receive the value of the single defined
; variable, or a null string if none is defined.
; COMMON BLOCKS:
; None.
; SIDE EFFECTS:
; None.
; RESTRICTIONS:
; Currently ONE_OF is restricted to a maximum of 8 variables. If needed,
; the number can be increased.
; PROCEDURE:
; Straightforward.
; MODIFICATION HISTORY:
; Created 15-JUL-1991 by Mati Meron.
; Modified 30-JUL-1991 by Mati Meron. The dependence of the original
; code on the EXECUTE system routine has been eliminated in order to
; assure compatibility with the OUTPUT routine.
; Modified 15-NOV-1993 by Mati Meron. Since IDL now allows for recursive
; calls to EXECUTE, the original code has been restored.
;-
on_error, 1
vnams = ['v_0','v_1','v_2','v_3','v_4','v_5','v_6','v_7']
exlist = lonarr(8)
exind = -1l
val = ''
for i = 0, n_params() - 1 do idum = $
execute('exlist(i) = n_elements(' + vnams(i) + ')')
wex = where(exlist gt 0, nex)
if nex eq 1 then begin
exind = wex(0)
idum = execute('val = ' + vnams(exind))
endif else if nex gt 1 then message, 'Only one variable may be defined!'
return, exind
end
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
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| Re: IDL- variable variable names [message #7375 is a reply to message #7372] |
Thu, 07 November 1996 00:00 |
davidf
Messages: 2866
Registered: September 1996
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Senior Member |
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I wrote in a previous article:
> But..., I got about this close:
>
> FUNCTION MAGIC, file
> number = 0
> ok = EXECUTE(file + ' = 0')
> RESTORE, file
> RETURN, number
> END
>
> IDL> a = 10
> IDL> number = a
> IDL> Save, a, number, Filename='a'
> IDL> b = 'a'
> IDL> c = Magic(b)
> IDL> IF c EQ 10 THEN Print, "It's magic!"
>
> It's magic!
Here is an obvious modification that I overlooked that nudges it
even closer. And I added some help for the 8.3 crowd! :-)
FUNCTION MAGIC, file
number = 0
RESTORE, file + '.sav'
RETURN, number
END
IDL> a = 10
IDL> number = a
IDL> Save, number, Filename='a.sav'
IDL> b = 'a'
IDL> c = Magic(b)
IDL> IF c EQ 10 THEN Print, "It's magic!"
It's magic!
This almost borders on the useful now. What do you have
in mind for this, Hendrik?
David
*************************************************
* David Fanning, Ph.D.
* 2642 Bradbury Court, Fort Collins, CO 80521
* Phone: 970-221-0438 Fax: 970-221-4762
* E-Mail: davidf@dfanning.com
*
* Sometimes I go about pitying myself, and all along my
* soul is being blown by great winds across the sky.
* -- Ojibway saying
************************************************
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| Re: IDL- variable variable names [message #7376 is a reply to message #7375] |
Thu, 07 November 1996 00:00 |
davidf
Messages: 2866
Registered: September 1996
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Senior Member |
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Hendrik Roepcke <alpha@jungle.toppoint.de> writes:
> i want to play with IDL Variable names.....Look:
> a=10
> b="a"
> c=print,MAGIC("b")
> if c eq 10 then print," its magic!"
>
> So: How to programm this function MAGIC????
This looks like deja vu all over again. Here is the
answer: Ain't no way, no how!
But..., I got about this close:
FUNCTION MAGIC, file
number = 0
ok = EXECUTE(file + ' = 0')
RESTORE, file
RETURN, number
END
IDL> a = 10
IDL> number = a
IDL> Save, a, number, Filename='a'
IDL> b = 'a'
IDL> c = Magic(b)
IDL> IF c EQ 10 THEN Print, "It's magic!"
It's magic!
David
*************************************************
* David Fanning, Ph.D.
* 2642 Bradbury Court, Fort Collins, CO 80521
* Phone: 970-221-0438 Fax: 970-221-4762
* E-Mail: davidf@dfanning.com
*
* Sometimes I go about pitying myself, and all along my
* soul is being blown by great winds across the sky.
* -- Ojibway saying
************************************************
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