[R] identify and delete in table
jim holtman
jholtman at gmail.com
Mon Feb 27 15:44:41 CET 2012
Is this what you want:
> ds1 <- read.table(text = "1 A
+ 2 B
+ 3 X
+ 4 AA
+ 5 A
+ 6 D
+ 7 XA
+ 8 C", as.is = TRUE)
>
> ds2 <- read.table(text = "1 A
+ 2 X
+ 3 A", as.is = TRUE)
>
> # find matches
> ds3 <- ds1[!(ds1$V2 %in% ds2$V2), ]
> ds3
V1 V2
2 2 B
4 4 AA
6 6 D
7 7 XA
8 8 C
On Mon, Feb 27, 2012 at 6:17 AM, Jonas Fransson <jf at iva.dk> wrote:
> 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
> D +45 32 34 15 10
> www.iva.dk/jf
>
>
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> and provide commented, minimal, self-contained, reproducible code.
--
Jim Holtman
Data Munger Guru
What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.
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