[R] Extracting the first element of a list

[Ko-Kang Kevin Wang]

Hi,

----- Original Message -----
From: "Uwe Ligges" <ligges at amadeus.statistik.uni-dortmund.de>
To: "Ross Darnell" <r.darnell at shrs.uq.edu.au>
Cc: <r-help at stat.math.ethz.ch>
Sent: Wednesday, March 27, 2002 8:03 PM
Subject: Re: [R] Extracting the first element of a list


> For the first element of a list L:
>  L[[1]]
> For the first elements of all elements (vector) of the list:
>  lapply(L, function(x) x[1])

So, suppose I've got a vector called foo, which has elements as follows:
  305 159 251 215 101 224 306 199 194 325 329 221 318 238  17 ....
(the rest omittied)

And suppose I want to extract out the first digit of each number, so like:
  3 1 2 2 1 2 3 1 1 3 3 2 3 2 1...

Do I still use
  lapply(foo, function(x) x[1])
it doesn't seem to work...

Thanks

Kevin

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> Uwe Ligges
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