4

I have multiple observations of one species with different observers / groups of observers and want to create a list of all unique observers. My data look like this: 

data <- read.table(text="species observer
1 A,B
1 A,B
1 B,E
1 B,E
1 D,E,A,C,C
1 F"               , header = TRUE, stringsAsFactors = FALSE)

My output should return a list of all unique observers - so: 

A,B,C,E,F

I tried to substring the data in column C using the following command but that only returns the unique combinations of observers. 

all_observers <- unique(strsplit(as.character(data$observer), ","))

all_observers
[[1]]
[1] "A" "B"

[[2]]
[1] "B" "E"

[[3]]
[1] "D" "E" "A" "C" "C"

[[4]]
[1] "F"
zx8754
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Kanoet
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3 Answers3

5

You're almost there, you just need to unlist before you do the unique:

all_observers <- unique(unlist(strsplit(as.character(data$observer), ",")))
Gregor Thomas
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2

We can use separate_rows on the 'observer', get the distinct rows, grouped by 'species', and paste the 'observer'

library(tidyverse)
data %>% 
   separate_rows(observer) %>% 
   distinct %>% 
   group_by(species) %>% 
   summarise(observer = toString(observer))
akrun
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2

You could also use scan()

unique(scan(text=data$observer, what="", sep=","))
# Read 14 items
# [1] "A" "B" "E" "D" "C" "F"
Rich Scriven
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