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Re: How to judge a Function's parameters ? [message #66272 is a reply to message #66271]

Thu, 07 May 2009 15:01

Paul Van Delst[1]
Messages: 1157
Registered: April 2002

Senior Member

Hu wrote:
> Hi,folks,
>
> I created a function 'RectArea' to calculate the rectangle area, and
> two parameters, side a and b, are needed when the function is
> employed.
>
> I want to do something like this: if a and b are omitted by the user,
> then the function will use the default values.
>
> But, How can I judge that the parameters are omitted?
>
> Thanks
>
> function RectArea,a,b
> return,a*b
> end

function RectArea,a,b
if ( n_elements(a) eq 0 ) then a = 1 ; or whatever default value
if ( n_elements(b) eq 0 ) then b = 1 ; or whatever default value
return,a*b
end

Although, I would rather an error be thrown if required arguments are missing.

cheers,

paulv

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[Message index]

		Re: How to judge a Function's parameters ? By: Michael Galloy on Thu, 07 May 2009 15:02
		Re: How to judge a Function's parameters ? By: Paul Van Delst[1] on Thu, 07 May 2009 15:01
		Re: How to judge a Function's parameters ? By: Paul Van Delst[1] on Thu, 07 May 2009 15:32

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