R help - Mar 2013 - Select rows from Data Frame with conditions

Hi all,

I have two dataframes. The first (A) contains all the stock prices for
today including today. So the first column is the stock Symbol and the
second column is the stock price. The second (B) is the symbol list in the
top 100 stocks.

I want to pick out from dataframe A only the rows containing the symbols
from B. i.e. something like:

            prices <- A[A[,1]==B,2]

is there any way to do this without using a for loop, I have to do this 365
times (i.e. for one year).

Thanks,
Sachin

	[[alternative HTML version deleted]]

Something along the lines of

top100 <- A[match(B,A[,1]),]

Please provide R code with sample data and desired output. See
http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example
---------------------------------------------------------------------------
Jeff Newmiller                        The     .....       .....  Go Live...
DCN:<jdnewmil at dcn.davis.ca.us>        Basics: ##.#.       ##.#.  Live
Go...
                                      Live:   OO#.. Dead: OO#..  Playing
Research Engineer (Solar/Batteries            O.O#.       #.O#.  with
/Software/Embedded Controllers)               .OO#.       .OO#.  rocks...1k
--------------------------------------------------------------------------- 
Sent from my phone. Please excuse my brevity.

Sachinthaka Abeywardana <sachin.abeywardana at gmail.com> wrote:
>Hi all,
>
>I have two dataframes. The first (A) contains all the stock prices for
>today including today. So the first column is the stock Symbol and the
>second column is the stock price. The second (B) is the symbol list in
>the
>top 100 stocks.
>
>I want to pick out from dataframe A only the rows containing the
>symbols
>from B. i.e. something like:
>
>            prices <- A[A[,1]==B,2]
>
>is there any way to do this without using a for loop, I have to do this
>365
>times (i.e. for one year).
>
>Thanks,
>Sachin
>
>	[[alternative HTML version deleted]]
>
>______________________________________________
>R-help at r-project.org mailing list
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.

On 03/08/2013 02:22 PM, Sachinthaka Abeywardana wrote:
> Hi all,
>
> I have two dataframes. The first (A) contains all the stock prices for
> today including today. So the first column is the stock Symbol and the
> second column is the stock price. The second (B) is the symbol list in the
> top 100 stocks.
>
> I want to pick out from dataframe A only the rows containing the symbols
> from B. i.e. something like:
>
>              prices <- A[A[,1]==B,2]
>
> is there any way to do this without using a for loop, I have to do this 365
> times (i.e. for one year).
Is "B" a data frame, or a vector?

Any I think you want to do something like (untested):

     prices <- A[A[,1] %in% B[,1],2]

     cheers,

         Rolf Turner