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Re: An expression calculator? [message #36204]

Mon, 11 August 2003 18:19

Weimin Wang
Messages: 7
Registered: October 2002

Junior Member

I got it.The execute function may complete my task.:)

Weimin Wang 写锟斤拷锟斤拷
>
> Hi,all
>
> Now i have a simple program written.However,I encounter a problem.A
> mathematical expression stored as string variable is inputed to my
> procedure.I want to calculate its value with after parameter are
> known.Does someone have an experience finishing such a mission?
>
> Many thanks in advance.
>

--
Best Regards,

Wang Weimin

WaterCenter,Institute of Geo.
Sci. & Nature Resource Research,
Chinese Academy of Science,
Beijing,100101,China
Tel:86-10-64889762-5

http://qtirsl.igsnrr.ac.cn

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Re: An expression calculator? [message #36214 is a reply to message #36204]

Mon, 11 August 2003 09:16

R.Bauer
Messages: 1424
Registered: November 1998

Senior Member

Weimin Wang wrote:

> Hi,all
>
> Now i have a simple program written.However,I encounter a problem.A
> mathematical expression stored as string variable is inputed to my
> procedure.I want to calculate its value with after parameter are
> known.Does someone have an experience finishing such a mission?
>
> Many thanks in advance.
>

Dear Weimin

there are several solution possible,

The oldest one ist to use execute. But then the routine won't run by vm or
rt.

a=6
b=7

x=execute('result=a+b')
print,result
13

One other posibility is to write a routine like icgs_calc.

http://www.fz-juelich.de/icg/icg-i/idl_icglib/idl_source/idl _html/dbase/icgs_calc_dbase.pro.html

One other is to write the string to a function, declare the input variables
for the function and then call the function by call function.

regards
Reimar

--
Forschungszentrum Juelich
email: R.Bauer@fz-juelich.de
http://www.fz-juelich.de/icg/icg-i/
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