How to reorganise data frame by multiple categories

Question

I have a dataframe with multiple groups that appear in various samples and would like to organise it by samples

I have several groups of variables with different values. Each group is part of a sample and might appear in several samples (just different value for different sample) but might not. I wish to organise the data frame so every row is a sample, every column is a group and for samples for which there is no value, a 0 should be added.

Groups<-sample(1:9,replace = T)
SampData<-data.frame(Group=LETTERS[Groups],Value=sample(1:9,replace = T),Sample=c(1,2,3,1,1,2,2,4,3))

This is a sample data frame:

   Group Value Sample
1     A     5      1
2     I     5      2
3     A     1      3
4     H     7      1
5     E     7      1
6     D     6      2
7     B     1      2
8     E     4      4
9     B     6      3

I would like to reorganise it so it looks like this:

   A  B  D  E  H  I
1  5  0  0  7  7  0
2  0  1  6  0  0  5
3  1  6  0  0  0  0
4  0  0  0  4  0  0

you are looking for the `spread` function from `dplyr` package — fmarm, Jun 27 '19 at 12:54
you are looking for the `reshape` function from `base` package — Parfait, Jun 27 '19 at 13:05

score 0 · Accepted Answer · answered Jun 27 '19 at 13:17

0

You can use dcast within reshape2:

library(dplyr)
library(reshape2)
set.seed(123)

Groups<-sample(1:9,replace = T)
SampData<-data.frame(Group=LETTERS[Groups],Value=sample(1:9,replace = T),Sample=c(1,2,3,1,1,2,2,4,3))

df <- SampData %>%
  dcast(Sample ~ Group, value.var = "Value", fun.aggregate = sum)

answered Jun 27 '19 at 13:17

Bjørn Kallerud

979
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23

Thanks a lot, that did the trick – B.Shermeister Jun 30 '19 at 10:54

How to reorganise data frame by multiple categories

1 Answers1