identify and delete in table

ds1 <- read.table(text = "1 A

ds2 <- read.table(text = "1 A

# find matches
ds3 <- ds1[!(ds1$V2 %in% ds2$V2), ]
ds3

Dear all,

I want to delete the exact matches in a large dataset based on a smaller dataset. In other words I want to subtract the smaller dataset from the larger one. The smaller dataset is a part of the larger one. The datasets contains hundred of thousands of lines (1 column) and the content on each line differ in length. The data is extracted paths from web logs.

On an abstract level I want to subtract dataset2 from dataset1 to get dataset3:

dataset1:
1 A
2 B
3 X
4 AA
5 A
6 D
7 XA
8 C

dataset2:
1 A
2 X
3 A

dataset3:
1 B
2 AA
3 D
4 XA
5 C

The final order in dataset3 is not important.

Thanks,

Jonas Fransson
Ph.D.stud.

IVA / Det Informationsvidenskabelige Akademi
Royal School of Library and Information Science
Birketinget 6
DK-2300 Copenhagen S
T +45 32 58 60 66
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www.iva.dk/jf