Aggregate in multiple columns

Question

I've multiple stations (+1000) with more than 50 years to work on it, so I configured my df with the stations on the columns and dates on rows as the example. Now I need to make summations of my parameter for each year in each column of data, but also i must know how many fields with no NA it counted to give me a specific value for each year in each station. I hope you guys can help me, and sorry about the syntax and language.

year<-c(rep(2000,12),rep(2001,12),rep(2002,12), rep(2003,12))
data <- data.frame( year, month=rep(1:12,4),est1=rnorm(12*4,2,1),est2=rnorm(12*4,2,1),est3=rnorm(12*4,2,1))
data[3,3]<-NA

A fairly-common question, did you search on SO before asking the question? — r2evans, Jun 14 '17 at 06:01

Łukasz Deryło · Accepted Answer · 2017-06-14T06:13:10.080

1

Sums:

> apply(data[,-(1:2)], 2, tapply, data$year, sum, na.rm=T)
         est1     est2     est3
2000 23.46997 21.36984 28.24381
2001 27.32517 28.84098 24.11784
2002 23.41737 25.47548 23.82606
2003 24.63551 24.51148 28.17723

Non NA's:

> apply(!is.na(data[,-(1:2)]), 2, tapply, data$year, sum)
     est1 est2 est3
2000   11   12   12
2001   12   12   12
2002   12   12   12
2003   12   12   12

And a version without apply (see @r2evans comment below):

sapply(data[,-(1:2)], tapply, data$year, sum, na.rm=T)

sapply(data.frame(!is.na(data[,3:5])), tapply, data$year, sum)

edited Jun 14 '17 at 06:13

answered Jun 14 '17 at 06:05

Łukasz Deryło

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Don't use `apply` with `data.frame`s, it's bad practice and will break if there's a non-`numeric` column. – r2evans Jun 14 '17 at 06:06
OK, I added a `sapply`-version. That's ugly.. :) – Łukasz Deryło Jun 14 '17 at 06:14
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This is just an aggregate operation isn't it? `aggregate(data[c("est1","est2","est3")], data["year"], FUN=sum, na.rm=TRUE)` – thelatemail Jun 14 '17 at 06:17
To answer your last question I did a lot searching. There are some things that I cant understand. Why are we using data[,-(1:2)] then 2? – Matias Zuñiga Jun 14 '17 at 06:20
We don't want to sum years or months, that's why we use `data[,-(1:2)]`. And we want sum columns, that's why we use `2`. Type `?apply` and read it's help page. This sholud help. – Łukasz Deryło Jun 14 '17 at 06:23
whenever i make this with many row/col i cant watch the whole results, what can i do?, should i export it? – Matias Zuñiga Jun 14 '17 at 06:24
Yes, that's probably the best idea – Łukasz Deryło Jun 14 '17 at 06:29

Aggregate in multiple columns

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