VERY nice. That certainly works. Now how does one plot all three
variables on one graph? :-)
Thanks very much.
Ira
On Feb 5, 2009, at 7:29 PM, Phil Spector wrote:
Ira -
As you say, there are many ways to solve this problem.
Here's one of them:
list=c("MSFT","AAPL","ORCL")
getSymbols(list)
#First, create a function that will take the name of a variable,
#get the Close value from it and pass it to the Delt function:
makedelt = function(l){now = get(l) ;
Delt(now[,paste(l,".Close",sep='')])}
#Now create a list of the results from Delt:
allclose = lapply(list,makedelt)
#Finally pass the list to Reduce to merge them all together:
result = Reduce(merge,allclose)
#To better identify the columns, you can use
colnames(result) = list
Hope this helps.
- Phil Spector
Statistical Computing Facility
Department of Statistics
UC Berkeley
spec...@stat.berkeley.edu
On Thu, 5 Feb 2009, Fuchs Ira wrote:
These are all great resposes but I think I should have given a
slightly more complete description of the problem.
I am using the quantmod package and I have called getSymbols with a
character vector that has a list of stock symbols. For example:
library("quantmod")
list=c("MSFT","AAPL","ORCL")
getSymbols(list)
this returns 3 objects (MSFT,AAPL, ORCL)
now imagine that I want to use the Delt function (also in quantmod)
to
calculate the percent difference for each of these stocks using their
closing price.
each closing price is SYMBOL$SYMBOL.Close (can also be retrieved with
Cl(SYMBOL)
I want to construct the call to Delt with the symbols in list
appended
with $SYMBOL.Adjusted
in other words I want a way to create
Delt(MSFT$MSFT.Close) merged with Delt(AAPL$AAPL.Close) and so on
(one object having the result of the Delt function for each stock).
I am sure that there are many ways to solve this particular problem.
Perhaps what I need to understand is how to take the characters in
the
list and construct an expression and then evaluate the expression.
On Feb 5, 2009, at 5:50 PM, <markle...@verizon.net> wrote:
Hi: there's mget but I couldn't figure out how to use it. if you
figure
it out, let me know.
I'm sure one of the guRus will reply with something that uses mget.
List
is slow now
because Europe is sleeping. Good luck.
On Thu, Feb 5, 2009 at 5:42 PM, Ira Fuchs wrote:
Thanks, that is better but doesn't actually solve my problem which
is
that n is an arbitrary length vector and I'd like to find a way
that
avoids having to enumerate the elements of the character vector.
Thanks,
Ira
----- Original Message -----
From: markle...@verizon.net <markle...@verizon.net>
To: Fuchs Ira <irafu...@gmail.com>
Sent: Thu Feb 05 17:25:39 2009
Subject: RE: [R] eval and as.name
Hi: below works but it's not much shorter than yours. there must
be a
better way so I'm sending off line in order to encourage better
replies.
sum(get(n[1]),get(n[2]))
On Thu, Feb 5, 2009 at 5:10 PM, Fuchs Ira wrote:
I'm sure there is a more general way to ask this question but how
do
you use the elements of a character vector as names of objects in
an
expression?
For example, say you have:
a = c(1,3,5,7)
b = c(2,4,6,8)
n=c("a","b")
and you want to use the names a and b in a function (e.g. sum)
sum(eval(as.name(n[1])),eval(as.name(n[2])))
works but
what is a simpler way to effect this level of indirection?
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and provide commented, minimal, self-contained, reproducible code.
______________________________________________
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
