[R] Counting the loop-round of a "for"-loop

[Ista Zahn]

Hi,

You can initialize a counter and update it in the loop. An silly example 
(unrelated to yours because it was not reproducible) of this technique is:


x <- matrix( , ncol = 2, nrow = 26)

n <- 0
for(i in letters) {
  n <- n+1
  x[n,] <- c(i, n)
}


Best,
Ista


On Sunday, February 12, 2012 07:17:33 AM jolo999 wrote:
> Dear all,
> 
> i have daily stock prices for more than 10 years and want to compute annual
> volatilities for certain dates during this period.  Since i have found no
> "easy" way to work with time data, the data presents itself in the structure
> 
> TIme Index - Stock Price
> 1 - 15,6
> 2 - 17
> ...
> ...
> 2010 - 28
> 2011- 28,5
> ...
> 4500 - 23
> 
> Since I want to have the volatility only for certain dates, I define these
> dates in a vector
> 
> Deal_Dates <- c(500,600,700,805)
> 
> and use the for-command to calculate these specific volatities via
> 
> for(i in Deal_Dates){Volatility(i)}
> 
> My problem is now, that I want to save the results in a new matrix which i
> created in the structure
> 
> results <- matrix(rep(NA,4*2),4,2) in a way that
> 
> Time Index - Volatility
> 500 - 0.55
> 600 - 0.44
> 700 - 0.45
> 805 - 0.66
> is stored in the results matrix.
> 
> How can I save the result of each for-loop  in the matrix? I want the
> respective Time-Index of the loop to be put in the first column and the
> volatility in the second column. Since my vector for the for-loop consists
> of "random" values for the Time-Index, i can't write
> 
> resultsl[i,1] = Time Index and
> results[i,2] = Volatility
> 
> I am looking for something that gives me the current round or iteration of
> the for-loop in order to replace the "i" in adressing the cells of the
> result matrix.
> 
> Hope you can help!
> 
> 
> --
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> 19p4381319.html Sent from the R help mailing list archive at Nabble.com.
> 
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