Message-ID: <510F8711.5080205@ymail.com>
Date: 2013-02-04T10:01:53Z
From: Pascal Oettli
Subject: Script for conditional sums of vectors
In-Reply-To: <894643FDEA3A854A89B3E828737E2B1FF3003D4CDA@HERMES8.ds.leeds.ac.uk>
Hello,
First, don't use "data" for a data frame, as it is a R function.
Here is a way to do what you are looking for:
a=c(1,1,1,1,1,1,2,2,2,2,2,2)
b=c(1,1,1,2,3,4,1,1,2,2,3,4)
c=c(400,200,300,100,500,300,200,100,500,400,200,100)
dat=data.frame(a=a,b=b,c=c)
dat.sum <- aggregate(c ~ a+b, dat, sum)
dat.sum <- reshape(dat.sum, timevar='b', idvar='a', direction='wide')
colnames(dat.sum) <- c('a','b.1','b.2','b.3','b.4')
HTH,
Pascal
Le 04/02/2013 18:29, Benjamin Gillespie a ?crit :
> Hi guys,
>
> I hope you can help me with this (probably) simple query:
>
> I have a data frame:
>
> --------------------------
>
> a=c(1,1,1,1,1,1,2,2,2,2,2,2)
> b=c(1,1,1,2,3,4,1,1,2,2,3,4)
> c=c(400,200,300,100,500,300,200,100,500,400,200,100)
>
>
> data=data.frame(a=a,b=b,c=c)
>
> --------------------------
>
> And I would like to get the following output:
>
> --------------------------
>
> b
> a 1 2 3 4
> 1 900 100 500 300
> 2 300 900 200 100
>
> --------------------------
>
> The values in the output represent the sum of values "c" in data frame "data", for each "a" and "b" combination.
>
> For example, where "a" = 1 and "b" = 1, the output is 400+200+300 = 900.
>
> Please would anyone be able to provide a script to create my desired output?
>
> Many thanks in advance,
>
> Ben Gillespie
> Research Postgraduate
>
> School of Geography
> University of Leeds
> Leeds
> LS2 9JT
>
>
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> and provide commented, minimal, self-contained, reproducible code.
>