Extract specific rows from spreadsheet using a key with R-CodePudding

I have a spreadsheet Y that has thousands of rows

I would like to extract a few hundred specific rows identified by key X

I used intersect function to generate object Z as below, but do not know how to proceed.

Many thanks

Z<-intersect(X$PatientID, Y$Patient.ID)

CodePudding user response：

Try using %in%: Sample Data

Y <- data.frame(PatientID = LETTERS,
                Var1 = 1:26)

key <- data.frame(PatientID = c("A", "W", "V"),
                  Var1 = c(1, 22:23))

Using %in%:

want <- Y[Y$PatientID %in% key$PatientID, ]

Output:

#    PatientID Var1
# 1          A    1
# 22         V   22
# 23         W   23

Note if you needed to use intersect, you would just do this:

Z <- intersect(Y$PatientID, key$PatientID)

want <- Y[Y$PatientID %in% Z,]

And it would give you the same output

CodePudding user response：

You can merge:

base R

merge(Y,unique(X[,"PatientID",drop=F]))

dplyr:

dplyr::inner_join(Y, dplyr::distinct(X,PatientID))