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

From: Ivan Calandra <ivan.calandra_at_uni-hamburg.de>
Date: Fri, 04 Mar 2011 15:39:30 +0100

I have never used it, but I think the reshape and/or reshape2 packages are designed for it.
Check the melt() and cast() functions in these packages... I guess...

Ivan

Le 3/4/2011 11:33, Dmitrij Kudriavcev a écrit :
> Hello, no. I need to change data format, so i can build covariance matrix on
> it
>
> Cheers,
> Dima
>
> 2011/3/4 Alberto Negron<albertonegron_at_gmail.com>
>
>> Can't you just convert you df as follow matrix<- as.matrix(s) ?
>>
>> Double check it as I am a newbie too. :-)
>>
>> Regards,
>>
>> Alberto
>>
>> On 4 March 2011 06:08, Dmitrij Kudriavcev<dimitrij.kudriavcev_at_ntsg.lt>wrote:
>>
>>> 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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>>
> [[alternative HTML version deleted]]
>
> ______________________________________________
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>

-- 
Ivan CALANDRA
PhD Student
University of Hamburg
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Received on Fri 04 Mar 2011 - 14:41:12 GMT

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