Compare occurrences between 2 dataframes in R

Question

I would like to compare to a string frequence between two dataframes in R.

My first dataframe (X):

 List1
 Engl001
 Engl002
 Engl003

My second dataframe (Y):

 List1    ram
Engl001   noi2
Engl001   oui5
Engl003   ki4

My expected output:

  List1    Count
 Engl001    2
 Engl002    0
 Engl003    1

Thank you!

Answer 1

This would be a solution

A<-read.table(text=" List1
 Engl001
 Engl002
           Engl003", header=TRUE,colClasses = "character")

B <- read.table(text=" List1    ram
Engl001   noi2
Engl001   oui5
Engl003   ki4", header=TRUE,colClasses = "character")

CAUTION: A$List1 and B$List1 are of class character!

tmp<-sapply(A$List1,function(x){sum(B$List1==x)})
data.frame(List1=names(tmp),Count=tmp)

Result:

          List1 Count
Engl001 Engl001     2
Engl002 Engl002     0
Engl003 Engl003     1

Answer 2

Using factors and table:

# Dummy data
X <- read.table(text=" List1
 Engl001
 Engl002
              Engl003", header=TRUE,colClasses = "character")
Y <- read.table(text=" List1    ram
                Engl001   noi2
                Engl001   oui5
                Engl003   ki4", header=TRUE,colClasses = "character")

# get counts, add colnames
result <- as.data.frame(table(factor(Y$List1,levels=unique(X$List1))))
colnames(result) <- c("List1","Count")

# Output
result
# List1 Count
# 1 Engl001     2
# 2 Engl002     0
# 3 Engl003     1

Thanks to @hardingnj at Biostar