Re: [R] sum of certain length

2010-05-23 Thread Gabor Grothendieck 
If the days are consecutive with no missing rows then the dates don't
need to be calculated and it could be represented as a ts series with
a frequency of 7.  Just aggregate it down to a frequency of 1:

   rain <- ts(dat$rain, freq = 7)
   aggregate(rain, 1)

If there are missing rows (or even there are none missing) you could
use zoo.  This time lets use dates:

   library(zoo)
   rain <- with(dat, zoo(rain, as.Date(paste(year, month, day, sep = "-"
   week <- 7 * (as.numeric(time(rain)-start(rain)) %/% 7) + start(rain) + 6
   aggregate(rain, week)

Each point in the aggregated series is associated with the date of the
end of its week.


On Sun, May 23, 2010 at 8:09 PM, Roslina Zakaria  wrote:
> Hi r-users,
>
> I have this data below.  I would like to obtain the weekly rainfall sum.  
> That is I would like to find sum for day 1 to day 7, day 8 - day15, and so on.
>    year month day rain
> 1  1922 1   1  0.0
> 2  1922 1   2  0.0
> 3  1922 1   3  0.0
> 4  1922 1   4  0.0
> 5  1922 1   5  0.0
> 6  1922 1   6  0.0
> 7  1922 1   7  0.0
> 8  1922 1   8  6.6
> 9  1922 1   9  1.5
> 10 1922 1  10  0.0
> 11 1922 1  11  0.0
> 12 1922 1  12  4.8
> 13 1922 1  13 14.7
> 14 1922 1  14  0.0
> 15 1922 1  15  0.0
> 16 1922 1  16  0.0
> 17 1922 1  17  0.0
> 18 1922 1  18  0.0
> 19 1922 1  19  0.0
> 20 1922 1  20  0.8
> 21 1922 1  21  0.0
> 22 1922 1  22  0.0
> 23 1922 1  23  0.0
> 24 1922 1  24  0.0
> 25 1922 1  25  0.0
> 26 1922 1  26  0.0
> 27 1922 1  27  0.0
> 28 1922 1  28  0.0
> 29 1922 1  29  0.0
> 30 1922 1  30  0.0
> 31 1922 1  31  0.0
> 32 1922 2   1  0.0
> 33 1922 2   2  0.0
> 34 1922 2   3  0.0
> 35 1922 2   4  0.0
> 36 1922 2   5  0.0
> 37 1922 2   6  0.0
> 38 1922 2   7  0.0
> 39 1922 2   8  0.0
> 40 1922 2   9  0.0
>
> Thank you.
>
>
>
>        [[alternative HTML version deleted]]
>
>
> __
> R-help@r-project.org mailing list
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
>

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Re: [R] sum of certain length

2010-05-23 Thread Bill.Venables 
This is one way to do it.  Suppose your data is in the file "rainfall.txt", as 
set out below.  Then

> dat <- read.table("rainfall.txt", header = TRUE)
> dat <- within(dat, {
+   date <- as.Date(paste(year, month, day, sep="-"))
+   week <- factor(as.numeric(date - date[1]) %/% 7)
+ })
> wRain <- with(dat, tapply(rain, week, sum))
> wRain
   012345 
 0.0 27.6  0.8  0.0  0.0  0.0 
> 

 

-Original Message-
From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On 
Behalf Of Roslina Zakaria
Sent: Monday, 24 May 2010 10:09 AM
To: r-help@r-project.org
Subject: [R] sum of certain length

Hi r-users,
 
I have this data below.  I would like to obtain the weekly rainfall sum.  That 
is I would like to find sum for day 1 to day 7, day 8 - day15, and so on.
   year month day rain
1  1922 1   1  0.0
2  1922 1   2  0.0
3  1922 1   3  0.0
4  1922 1   4  0.0
5  1922 1   5  0.0
6  1922 1   6  0.0
7  1922 1   7  0.0
8  1922 1   8  6.6
9  1922 1   9  1.5
10 1922 1  10  0.0
11 1922 1  11  0.0
12 1922 1  12  4.8
13 1922 1  13 14.7
14 1922 1  14  0.0
15 1922 1  15  0.0
16 1922 1  16  0.0
17 1922 1  17  0.0
18 1922 1  18  0.0
19 1922 1  19  0.0
20 1922 1  20  0.8
21 1922 1  21  0.0
22 1922 1  22  0.0
23 1922 1  23  0.0
24 1922 1  24  0.0
25 1922 1  25  0.0
26 1922 1  26  0.0
27 1922 1  27  0.0
28 1922 1  28  0.0
29 1922 1  29  0.0
30 1922 1  30  0.0
31 1922 1  31  0.0
32 1922 2   1  0.0
33 1922 2   2  0.0
34 1922 2   3  0.0
35 1922 2   4  0.0
36 1922 2   5  0.0
37 1922 2   6  0.0
38 1922 2   7  0.0
39 1922 2   8  0.0
40 1922 2   9  0.0

Thank you.


  
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[R] sum of certain length

2010-05-23 Thread Roslina Zakaria 
Hi r-users,
 
I have this data below.  I would like to obtain the weekly rainfall sum.  That 
is I would like to find sum for day 1 to day 7, day 8 - day15, and so on.
   year month day rain
1  1922 1   1  0.0
2  1922 1   2  0.0
3  1922 1   3  0.0
4  1922 1   4  0.0
5  1922 1   5  0.0
6  1922 1   6  0.0
7  1922 1   7  0.0
8  1922 1   8  6.6
9  1922 1   9  1.5
10 1922 1  10  0.0
11 1922 1  11  0.0
12 1922 1  12  4.8
13 1922 1  13 14.7
14 1922 1  14  0.0
15 1922 1  15  0.0
16 1922 1  16  0.0
17 1922 1  17  0.0
18 1922 1  18  0.0
19 1922 1  19  0.0
20 1922 1  20  0.8
21 1922 1  21  0.0
22 1922 1  22  0.0
23 1922 1  23  0.0
24 1922 1  24  0.0
25 1922 1  25  0.0
26 1922 1  26  0.0
27 1922 1  27  0.0
28 1922 1  28  0.0
29 1922 1  29  0.0
30 1922 1  30  0.0
31 1922 1  31  0.0
32 1922 2   1  0.0
33 1922 2   2  0.0
34 1922 2   3  0.0
35 1922 2   4  0.0
36 1922 2   5  0.0
37 1922 2   6  0.0
38 1922 2   7  0.0
39 1922 2   8  0.0
40 1922 2   9  0.0

Thank you.


  
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