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Re: array subtraction [message #63338]

Wed, 05 November 2008 08:39

Spon
Messages: 178
Registered: September 2007

Senior Member

On Nov 5, 4:29 pm, Wox <s...@nomail.com> wrote:
> On Wed, 5 Nov 2008 07:25:10 -0800 (PST), julia.waltersp...@gmail.com
> wrote:
>
>
>
>> hey guys
>> SOS call from the newbie:
>
>> I've got two data arrays, one of length 134 (=a), the other of length
>> 75 (=b) with monthly cloud cover data from modis terra and aqua.
>> Data from Terra starts feb 2000, data from Aqua starts july 2002.
>
>
> So you only need to get i in this:
> diff = a[i:*]-b
>

Hi,

Well if the time intervals are the same in both arrays (1 month), and
the last data point in both arrays is the same timepoint ('now'),
then I would do it this way:

na = n_elements(a)
nb = n_elements(b)

diff = abs(b-a[na-nb:*]) ; Given a>b as in your example

Or, if you really want a more general solution:
diff = abs(b[(nb-na>0):*] - a[(na-nb>0):*])

Regards,
Chris

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[Message index]

		Re: array subtraction By: Spon on Wed, 05 November 2008 08:39
		Re: array subtraction By: Wout De Nolf on Wed, 05 November 2008 08:29
		Re: array subtraction By: Brian Larsen on Wed, 05 November 2008 08:29
		Re: array subtraction By: julia.walterspiel on Wed, 05 November 2008 08:15
		Re: array subtraction By: R.Bauer on Wed, 05 November 2008 07:58
		Re: array subtraction By: julia.walterspiel on Mon, 10 November 2008 07:59

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