as.numeric(substr(as.character(foo),1,1))

does what you are looking for, although I don't understand why you should be

interested by collecting digit "3" from 305, together with digit "1" from

17. If you simply want to extract hundreds from numbers (thus, you will get

"0" for 17), then you could use:

floor(foo/100) - floor(foo/1000)*10

Best,

Philippe Grosjean

...........]<(({?<...............<?}))><...............................

) ) ) ) ) __ __

( ( ( ( ( |__) | _

) ) ) ) ) | hilippe |__)rosjean

( ( ( ( ( Marine Biol. Lab., ULB, Belgium

) ) ) ) ) __

( ( ( ( ( |\ /| |__)

) ) ) ) ) | \/ |ariculture & |__)iostatistics

( ( ( ( (

) ) ) ) ) e-mail: phgrosje at ulb.ac.be or phgrosjean at sciviews.org

( ( ( ( ( SciViews project coordinator (http://www.sciviews.org)

) ) ) ) ) tel: 00-32-2-650.29.70 (lab), 00-32-2-673.31.33 (home)

( ( ( ( (

) ) ) ) ) "I'm 100% confident that p is between 0 and 1"

( ( ( ( ( L. Gonick & W. Smith (1993)

) ) ) ) )

.......................................................................

-----Message d'origine-----

De : owner-r-help at stat.math.ethz.ch

[mailto:owner-r-help at stat.math.ethz.ch]De la part de Ko-Kang Kevin Wang

Envoy? : mercredi 27 mars 2002 11:48

? : Uwe Ligges; Ross Darnell

Cc : r-help at stat.math.ethz.ch

Objet : Re: [R] Extracting the first element of a list

Hi,

----- Original Message -----

From: "Uwe Ligges" <

ligges@amadeus.statistik.uni-dortmund.de>

To: "Ross Darnell" <

r.darnell@shrs.uq.edu.au>

Cc: <

r-help@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

Uwe Ligges

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