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uniq slow for loop [message #67270]

Thu, 16 July 2009 14:52

newerjazz
Messages: 5
Registered: July 2009

Junior Member

Hi All,

I have an array of [9,1,000,000]. In one of the columns are sorted
numbers (eg. 0,1,1,2,3,3,3,3,3,4,4,5,5,5,6,7,7,7,etc). I want to pick
out all the rows where column 9 is equal to some number and average
all the quantities in those rows.

Right now I use a for loop and the where function to pick out these
rows. This is of course very slow. Anyway to increase the speed of
this would be greatly appreciated. Thank you very much!

Cheers,
newerjazz

nmax = max(data(8,*))
FOR j=0, nmax DO BEGIN
w=where(data(8,*) eq j, nw)
blah=mean(data(*,w))
etc,etc
ENDFOR

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