CODEWITHSUNDEEP
rdplyrtidyverse
John Huang
John Huang

Reputation: 845

Copying a column into another dataframe based on matching columns

I have two data frames. The data frames are different lengths, but have the same IDs in their ID columns. I would like to create a column in df called Classification based on the Classification in df2. I would like the Classification column in the df to match up with the appropriate ID listed in df2. Is there a good way to do this?

#Example data set
library(lubridate)
date <- rep_len(seq(dmy("26-12-2010"), dmy("20-12-2011"), by = "days"), 500)
ID <- rep(seq(1, 5), 100)
ID2 <- rep(seq(1,5), 1)
Classification2 <- c("A", "B", "C", "D", "E")

df <- data.frame(date = date,
                 x = runif(length(date), min = 60000, max = 80000),
                 y = runif(length(date), min = 800000, max = 900000),
                 ID)

df2 <- data.frame(ID2, Classification)

Upvotes: 0

Views: 864

Answers (2)

tonybot
tonybot

Reputation: 655

A dplyr solution using left_join().

left_join(df, df2, c("ID" = "ID2"))

Upvotes: 1

gsolomon10
gsolomon10

Reputation: 365

Are you looking for a merge between df and df2? Assuming Classification is a column in df.

df2 <- merge(df2, df, by.x = "ID2", by.y = "ID", all.x = TRUE)

Upvotes: 0

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