如何删除 R 中的重复项？

Question

So I have file1.txt:

L["Corn Flakes"] = ""
L["Rice Oats"] = ""
L["Shreddies"] = ""

and file2.txt:

L["Marshmellows"] = "Tesco"
L["Golden Syrup"] = "Morrisons"
L["Corn Flakes"] = "Tesco"
L["Bran Flakes"] = "Asda"
L["Super Flakes"] = "Asda"
L["Rice Oats"] = "Asda"
L["Shreddies"] = "Morrisons"
L["Rice Krispies"] = "Tesco"

So I have this script which merges file2 into file1 but only for rows that exist in file1.

# Read file1
file1 <- read.table('file1.txt', sep = '=', quote = '', fill = TRUE)

# Remove commented out rows from file1
file1 <- file1[!grepl('--', file1$V1), ]

# Remove line that contains {}
file1 <- file1[!grepl('\\{\\}', file1$V2), ]

# Read file2
file2 <- read.table('file2.txt', sep = '=', quote = '', fill = TRUE)

# Remove rows from file2 if they are incomplete
file2 <- file2[!grepl('""', file2$V2),]

# Merge file1 and file2 into result but only including rows that are complete
result <- file2[file2$V1 %in% file1$V1, ]

# Write to file
write.table(result, 'result.txt', sep = '=', col.names = FALSE, row.names = FALSE, quote = FALSE)

The script works fine except for one small thing. I don't want result to include rows that are identical in file1 and file2. So if file1 contains L["Shreddies"] = "Tescos" and file2 contains L["Shreddies"] = "Tescos", I don't want L["Shreddies"] = "Tescos" to be included in result. How do I do this?

Answer 1

This should do it, after you run your existing code up to result and before write.table :

result <- unique(result)

EDIT after better understanding problem. I think this should do it:

result <- file2[(file2$V1 %in% file1$V1) &
                !(file2[c("V1", "V2")] %in% file1[c("V1","V2")]),]

One more EDIT:

result <- file2[(file2$V1 %in% file1$V1),]

library(dplyr)

result <- result %>% 
            anti_join(file1, by = c("V1", "V2"))