R - Excel VLOOKUP equivalent - Lookup, replace
r, vlookup
Solution
You are performing a join which in R is performed using the function `merge`
merge(db, df)
Using the `dplyr` package allows more natural verbs:
library(dplyr)
inner_join(db, df)
or perhaps (if you want non-matches to be shown; see `?left_join` for further information):
left_join(db, df)
Problem
I have looked pretty much everywhere and cannot find the answer to this; R equivalent of VLOOKUP on Excel. VLOOKUP allows me to look up for a specific value throughout a column and apply it to each row of my data frame. In this case I want to find the country a particular city is in (from a database) and return the name of the country in a new column. So I have this database: ``` countries <- c("UK", "US", "RUS") cities <- c("LDN", "NY", "MOSC") db <- cbind(countries, cities) db countries cities [1,] "UK" "LDN" [2,] "US" "NY" [3,] "RUS" "MOSC" ``` And want to find the country those cities are in (replace NA) based on the db above: ``` df countries cities [1,] NA "LDN" [2,] NA "NY" [3,] NA "MOSC" ``` I have absolutely no idea how to go about this on R.