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Re: FOR statement [message #24754 is a reply to message #24753]

Thu, 12 April 2001 09:12

Liam E. Gumley
Messages: 378
Registered: January 2000

Senior Member

Eli Beckerman wrote:
> I just tried running a FOR loop in the hopes
> of incrementing the variable "i" by steps of 0.25 as follows:
>
> radius=fltarr(1000)
> FOR i=0.0, 100.0, 0.25 DO BEGIN
>
> radius(i)=i
>
> ENDFOR
>
> And what I end up with is an array that starts
> with the value 0.75 and is incremented by steps of 1.
>
> I'm following the convention of the FOR statement as
> presented in IDL's online help. What am I doing wrong?!

You are using I as both an array index and a loop variable. This is not
a good idea.

Try this instead:

nx = 1000 ; number of values required
dx = 0.25 ; step size
x1 = 0.0 ; start value

radius = lindgen(nx) * dx + x1

print, radius[0:5]

Bottom line: Don't use loops to create mesh vectors or arrays.

Cheers,
Liam.
http://cimss.ssec.wisc.edu/~gumley/

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[Message index]

		Re: FOR statement By: Eli Beckerman on Fri, 13 April 2001 13:17
		Re: FOR statement By: Liam E. Gumley on Thu, 12 April 2001 14:04
		Re: FOR statement By: Eli Beckerman on Thu, 12 April 2001 12:41
		Re: FOR statement By: Craig Markwardt on Thu, 12 April 2001 09:18
		Re: FOR statement By: Liam E. Gumley on Thu, 12 April 2001 09:15
		Re: FOR statement By: Liam E. Gumley on Thu, 12 April 2001 09:12
		Re: FOR statement By: Paul van Delst on Thu, 12 April 2001 08:57
		Re: FOR statement By: John-David T. Smith on Thu, 12 April 2001 09:04

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