How to do vlookup and fill down (like in Excel) in R?

Question

I have a dataset about 105000 rows and 30 columns. I have a categorical variable that I would like to assign it to a number. In Excel, I would probably do something with

Answer 1

Solution #2 of @Ben's answer is not reproducible in other more generic examples. It happens to give the correct lookup in the example because the unique HouseType in houses appear in increasing order. Try this:

hous <- read.table(header = TRUE,   stringsAsFactors = FALSE,   text="HouseType HouseTypeNo
  Semi            1
  ECIIsHome       17
  Single          2
  Row             3
  Single          2
  Apartment       4
  Apartment       4
  Row             3")

largetable <- data.frame(HouseType = as.character(sample(unique(hous$HouseType), 1000, replace = TRUE)), stringsAsFactors = FALSE)
lookup <- unique(hous)

Bens solution#2 gives

housenames <- as.numeric(1:length(unique(hous$HouseType)))
names(housenames) <- unique(hous$HouseType)
base2 <- data.frame(HouseType = largetable$HouseType,
                    HouseTypeNo = (housenames[largetable$HouseType]))

which when

unique(base2$HouseTypeNo[ base2$HouseType=="ECIIsHome" ])
[1] 2

when the correct answer is 17 from the lookup table

The correct way to do it is

 hous <- read.table(header = TRUE,   stringsAsFactors = FALSE,   text="HouseType HouseTypeNo
      Semi            1
      ECIIsHome       17
      Single          2
      Row             3
      Single          2
      Apartment       4
      Apartment       4
      Row             3")

largetable <- data.frame(HouseType = as.character(sample(unique(hous$HouseType), 1000, replace = TRUE)), stringsAsFactors = FALSE)

housenames <- tapply(hous$HouseTypeNo, hous$HouseType, unique)
base2 <- data.frame(HouseType = largetable$HouseType,
  HouseTypeNo = (housenames[largetable$HouseType]))

Now the lookups are performed correctly

unique(base2$HouseTypeNo[ base2$HouseType=="ECIIsHome" ])
ECIIsHome 
       17

I tried to edit Bens answer but it gets rejected for reasons I cannot understand.