Re: FOR statement

["Liam E. Gumley" <Liam.Gumley(at)ssec.wisc.edu>]

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/