CODEWITHSUNDEEP
stringrdataframe
Mallvina
Mallvina

Reputation: 213

extract the values which match in both columns

I have data.frame of two columns with different size:

type1    type2
user1  user1
user2  user4
user3  user6
user4

how to get the matches? that the result would be

user1 
user4

Upvotes: 1

Views: 100

Answers (2)

flodel
flodel

Reputation: 89057

First of all, the columns in a data.frame must all have the same length (see http://cran.r-project.org/doc/manuals/R-intro.html#Data-frames.) so I will assume the last entry in your example is just an empty string "".

What you are looking for is the "intersection" of your two columns, i.e., the elements that can be found in both columns. You can use the intersect function for that:

df <- data.frame(type1 = c("user1", "user2", "user3", "user4"),
                 type2 = c("user1", "user4", "user6", ""))
df
#   type1 type2
# 1 user1 user1
# 2 user2 user4
# 3 user3 user6
# 4 user4      

intersect(df$type1, df$type2)
# [1] "user1" "user4"

Upvotes: 0

sgibb
sgibb

Reputation: 25726

See ?match or the similar ?"%in%":

df$type1[df$type1 %in% df$type2]

Upvotes: 1

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