mathijsdevaan wrote on 12/09/2010 04:21:54 PM:

> I have two columns with data (both identifiers - it's an affiliation

list)

> and I would like to delete the rows in which the observations in the

second

> column have a frequency < 5 in the entire second column. Example:

>

> 1 a

> 1 b

> 1 c

> 2 a

> 2 b

> 2 d

>

> Let's say, I would like to delete the rows in which the observation in

the

> second column has a frequency < 2 in the entire second column. This

would

> result in:

>

> 1 a

> 1 b

> 2 a

> 2 b

>

> How can I do this? Thanks in advance!

>

It's not clear whether you want to delete rows where the value second

column occurs less than 5 times or appears less than 2 times. I'll assume

the latter.

foo <- data.frame(k=rep(1:2, each=3), x=letters[c(1,2,3,1,2,4)])

bar <- subset(foo, x %in% names(table(foo$x))[table(foo$x)>=2])

No doubt others can write this more succinctly.

--

Curt Seeliger, Data Ranger

Raytheon Information Services - Contractor to ORD

[hidden email]
541/754-4638

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