[R] repeated searching of no-missing values

Patrizio Frederic frederic.patrizio at gmail.com
Thu Dec 11 15:56:25 CET 2008

dear Hadley and Bert,
thank you very much for your suggestions. I asked one question and I
learned 2 things:

1. Hadley,

ddply(data, .(V1), colwise(cl))

that is exactly what I was searching for.

2. Bert,

> ?tapply says that the first argument is an **atomic** vector. A
> factor is not an atomic vector. So tapply interprets it as such by looking
> only at its representation, which is as integer values.

I admit I payed not enough attention to the definition of **atomic** vector.
That implies a deeper understanding of structures of data. I'm working with!

Many thanks,


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