CODEWITHSUNDEEP
rlistdataframeintersect
Caro
Caro

Reputation: 95

Comparing character lists in R

I have two lists of characters that i read in from excel files One is a very long list of all bird species that have been documented in a region (allBirds) and another is a list of species that were recently seen in a sample location (sampleBirds), which is much shorter. I want to write a section of code that will compare the lists and tell me which sampleBirds show up in the allBirds list. Both are lists of characters.

I have tried:

# upload xlxs file
Full_table <- read_excel("Full_table.xlsx")
Pathogen_table <- read_excel("pathogens.xlsx")

# read species columnn into a new dataframe
species <-c(as.data.frame(Full_table[,7], drop=FALSE))
pathogens <- c(as.data.frame(Pathogen_table[,3], drop=FALSE))

intersect(pathogens, species)

intersect(species, pathogens)

but intersect is outputting lists of 0, which I know cannot be true, any suggestions?

Upvotes: 0

Views: 447

Answers (2)

Steves
Steves

Reputation: 3234

You need to run the intersect on the individual columns that are stored in the list:

> a <- c(data.frame(c1=as.factor(c('a', 'q'))))
> b <- c(data.frame(c1=as.factor(c('w', 'a'))))
> intersect(a,b)
list()
> intersect(a$c1,b$c1)
[1] "a"

This will probably do in your case

intersect(Full_table[,7], Pathogen_table[,3])

Or if you insist on creating the data.frames:

intersect(pathogens[1,], species[1,])

where [1,] should select the first column of the data.frame only. Note that by using c(as.data.frame(... you are converting the data.frame to a regular list. I'd go with only as.data.frame(....

Upvotes: 1

Carpa
Carpa

Reputation: 458

Maybe you can try match() function or "==".

Upvotes: 1

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