[R] How to copy data from data.frame to matrix

[Ivan Calandra]

Hi,

Let's say your data.frame is called df:
df <- data.frame(a=rnorm(10), b=rnorm(10))
data.matrix <- as.matrix(df)

This should work, but be careful with coercion if you have different 
modes in your data.frame

HTH,
Ivan

PS: next time, provide a reproducible example, using dput() for example

Le 3/4/2011 07:08, Dmitrij Kudriavcev a écrit :
> Hello
>
> I'm a new in R
> I have a large data.frame "s" (this is actualy just a table in mysql) :
>
>> names(s)
> [1] "symbols", "day", "value"
>
> I need to convert it to simple matrix. I have define this matrix like this:
>
>> data.matrix<- matrix(nrow=nDays, ncol=nSymbols, dimnames=list(days,
> symbols))
>
> then i just copy values to the matrix using for() loop, but it seems to take
> very long time. Is is a more fast way to do it in R? I know, what i can just
> gyve s$value as source data to the matrix, but problem is, what for some
> symbols couple days could be just missed.
>
> Cheers,
> Dima
>
> 	[[alternative HTML version deleted]]
>
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>

-- 
Ivan CALANDRA
PhD Student
University of Hamburg
Biozentrum Grindel und Zoologisches Museum
Abt. Säugetiere
Martin-Luther-King-Platz 3
D-20146 Hamburg, GERMANY
+49(0)40 42838 6231
ivan.calandra at uni-hamburg.de

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