Multi tool use

Converting between long and short data.frame formats

Simple (?) tidyr question:

tidyr

I have a data.frame which has several grouping columns and several value columns, in long format. I want to convert it to short (wide) format, where the key would be one of the grouping columns and the resulting data.frame would have a column for each combination of all the other grouping columns and each of the value columns.

data.frame

key

data.frame

Here's my long-format data.frame:

data.frame

set.seed(1)
library(dplyr)
df <- data.frame(treatment = rep(c(rep("T1",3),rep("T2",3)),2),
species = c(rep("S1",6),rep("S2",6)),
group = rep(LETTERS[1:3],4),
n = as.integer(runif(12,10,20))) %>%
dplyr::group_by(treatment,species) %>% dplyr::mutate(freq = n/sum(n))


And here's what I want the resulting wide-format data.frame to be:

data.frame

res.df <- data.frame(group = LETTERS[1:3],
T1.S1.n = dplyr::filter(df,treatment == "T1",species == "S1")$n,
T1.S1.freq = dplyr::filter(df,treatment == "T1",species == "S1")$freq,
T2.S1.n = dplyr::filter(df,treatment == "T2",species == "S1")$n,
T2.S1.freq = dplyr::filter(df,treatment == "T2",species == "S1")$freq,
T1.S2.n = dplyr::filter(df,treatment == "T1",species == "S2")$n,
T1.S2.freq = dplyr::filter(df,treatment == "T1",species == "S2")$freq,
T2.S2.n = dplyr::filter(df,treatment == "T2",species == "S2")$n,
T2.S2.freq = dplyr::filter(df,treatment == "T2",species == "S2")$freq)


1 Answer
1

We could use gather to convert to 'long' format, then unite the columns together and spread to 'wide'

gather

unite

spread

library(tidyverse)
gather(df, key, val, n:freq) %>%
unite(trtsp, treatment, species, key, sep = ".") %>%
spread(trtsp, val)


By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.