CODEWITHSUNDEEP
r
firmo23
firmo23

Reputation: 8444

Fill a dataframe column based on a common pair of values with another dataframe

I have the dataframe dtshp

id=c(0,0)
long<-c(140.9619,140.9626   )
lat<-c(-35.79979,-35.77946)
order<-c(1,2)
hole<-c(FALSE,FALSE)
piece<-c(1,1)
group<-c(0.1,0.1)
dtshp<-data.frame(id,long,lat,order,hole,piece,group)

and the dataframe dt

Town<-c("WATSONIA","NORTH MELBOURNE")
lat<-c(-35.79979,-35.77946)
long<-c(140.9619,140.9626)
pop<-c(1232131,213312)
dt<-data.frame(Town,lat,long,pop)
dt["id"] <- NA

How could I fill the values of dt$id with the values of dtshp$id when they have common pair of lat and long?

Upvotes: 0

Views: 98

Answers (2)

cardinal40
cardinal40

Reputation: 1263

library(dplyr)
dt %>% 
  left_join(dtshp, by = c("Longitude" = "long", "Latitude" = "lat"))

This will create columns in the merged data frame for id.x and id.y, since both data frames have a column for id. You could remove it from the dt data frame first, or use mutate/transmute/select after joining to choose the columns you want.

Upvotes: 2

sumshyftw
sumshyftw

Reputation: 1131

dt$id <- dtshp[dtshp$long == dt$long & dtshp$lat == dt$lat,]$id

which gives:

           Town       lat     long     pop id
       WATSONIA -35.79979 140.9619 1232131  0
NORTH MELBOURNE -35.77946 140.9626  213312  0

Upvotes: 1

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