similar to: searching for specific row in matrix

Hello, I have the following task I'd like to accomplish: A file contains 5 columns of data (several hundred rows), let's call them a, b, c, d and e (ie these are their column headers) I also have a set of definitions, e.g., f = a + b g = a * 3 h = c + d etc. I would like to write out a new .rda file that contains columns a b c d e f g h etc. I.e. , the original data plus new columns

Hello, which.max() only returns one index value, the one for the maximum value. If I want the two index values for the two largest values, is this a decent solution, or is there a nicer/better R'ish way? max2 <-function(v) { m=which.max(v) v[m] = -v[m] m2=which.max(v) result=c(m, m2) result } Seems to work ok. Thanks, Esmail

Hello, Still a newbie with R, though I have learned a lot from reading this list. I'm hoping someone can help with this question: I have two vectors, one for variables, and one for bits. I want to build a string (really a formula) based on the values in my vector of 1s and 0s in bits. If I have a one, I want to include the corresponding entry in the vars vector, otherwise ignore it. Of

Once again I need to tap into the collective knowledge here. Let's say I have the following columns and data below Y X1 X2 X3 X4 I would like to generate additional new columns and column names (ie the data would be squared - and I'd like the column names to reflect this) like: Y X1 X2 X3 X4 X1^2 X2^2 X3^2 X4^2 I believe I can compute the values correctly with the code below, but I

(sorry if this is a duplicate-problems with posting at my end) ---- Hello all, I need some help with a nice R-idiomatic and efficient solution to a small problem. Essentially, I am trying to eliminate randomly half of the entries in a vector that contains index values into some other vectors. More details: I am working with two strings/vectors of 0s and 1s. These will contain about 200

Hello all, I have a matrix of bit values. I compute certain values based on the bits in each row. There may be *duplicate* entries in the matrix, ie several rows may be identical. These rows change over time, and identical entries may not be next to each other. Computing these values is time consuming, so I would like a way to store a value once it's computed. That way I would be able to

Hi, I am trying to use the optimize function to optimize a function. The results I am getting don't agree with what I compute on my own and when I look at the graph of f(x) = 100 + ((x-10)**2 + (x-10)) * cos(x-10), where -10 <= x <= 10 in gnuplot. I suspect I am making a mistake in the usage of the R optimize function, perhaps someone could point out where? >

Hello all, I am trying to implement a simple Genetic Algorithm using some of the functions of R (such as lm). I am a total newbie with regard to R, but not programming or GAs. I thought I would have to do this in R but now it seems there are ways to call R functions from Java after all. (C++ would work for me too, having a compiled language should speed up the program.) Are there recommended

Colleagues, I have encountered behavior of random number generation that eludes me. I generate a random integer in a particular range using the following code: sample(1000:9999, size=1) This code exists within a script that starts with the command: remove(list=ls()) Each time that I run the script, it yields the same random number: 6420. I thought that the problem might result from

Hello all, Using Ubuntu 9.04 and R 2.8.1. For a project I need to use the Zelig package, which in turn wants to use the lme4 package. When trying to use Zelig and it tries to its required packages I get the following error message. Error in dyn.load(file, DLLpath = DLLpath, ...) : function 'cholmod_start' not provided by package 'Matrix' Error in loadModelDeps(model) :

I'm trying to compare two matrices made up of bits. doing a simple comparison of matA == matB yields this sort of output. [,1] [,2] [,3] [,4] [,5] [,6] [1,] FALSE TRUE FALSE TRUE TRUE FALSE [2,] TRUE TRUE TRUE TRUE TRUE TRUE [3,] FALSE TRUE FALSE FALSE FALSE TRUE [4,] FALSE TRUE TRUE FALSE FALSE FALSE [5,] TRUE TRUE TRUE TRUE FALSE FALSE [6,] TRUE TRUE

Perhaps most of you have already seen this? http://google-styleguide.googlecode.com/svn/trunk/google-r-style.html Comments/Critiques? Thanks, Esmail ps: Reminds me of PEP 8 for Python http://www.python.org/dev/peps/pep-0008/ Maybe not that surprising since Python is also one of the main languages used by Google.

Hello all, I have two matrices, pop and pop2, each the same number of rows and columns that I want to compare for equality. I am concerned about efficiency in this operation. I've tried a few things without success so far. Doing something simple like: if (pop==pop2) { cat('equal') } else { cat('NOT equal') } results in the warning: 1: In if (pop == pop2) { : the

I have a string of binary values, and I would like to flip certain bits in a set of positions. Let's say the vector p contains position [1, 3, 5, 7] vector b contains bits [1, 0, 1, 0, 1, 0, 1, 0, 1, 0] result r should be [0, 1, 0, 0, 0, 0, 0, 0, 1, 0] in pseudo code this would be something like --- r = c() for (i in 1:10) if (i in p) r = c(r, flip[i]) r ----

Hello all, I have the following function call to create a matrix of POP_SIZE rows and fill it with bit strings of size LEN: pop=create_pop_2(POP_SIZE, LEN) I have 3 questions: (1) If I did keep_pop[1:POP_SIZE] == pop[1:POP_SIZE] to keep a copy of the original data structure before manipulating 'pop' potentially, would this make a deep copy or just shallow? Ie

Hello all, I am stuck with R v2.8.0 under Linux for the time being and I am running into a small problem that doesn't exist under 2.9.x and 2.10.x with sprintf. If I have the following code segment to help me determine the column number for a specific column header/label: nn = names(Dataset) s = "Group" c = which(nn==s) cat(sprintf('found %s in col %d\n', s, c))

Dear sir, I am using R in windows. I want to extend R Memory size. I use the following command, but unfortunately it doesn't work. -- vsize=15M --nsize=1000K Your help is appreciated. Thanks, Esmail Amiri. __________________________________________________ Do You Yahoo!? Get email at your own domain with Yahoo! Mail. http://personal.mail.yahoo.com/

Hello, would someone please help explain the following inconsistency in the if/else statement to me? The format of the if/else #3 below is ok, but if/else #1 is not? (I get an "unexpected else" type error.) In order for it to work I have to use if/else #2 Thanks .. maybe there is some reason for this, but this looks very inconsistent to me. R version 2.10.1 (2009-12-14) Ubuntu 9.04

Hello all, I would like to maximize or minimize a given math function over a specific set of values. I was checking out Wolfram Alpha (http://www70.wolframalpha.com/) and it can do simple optimization problems in math, such as maximize 15*x - x**2 over 0 to 15 (http://www70.wolframalpha.com/input/?i=maximize+15*x+-+x**2+over+0+to+15) which finds the maximum value and input for x in

I've been trough the R documentation for about half an hour and it's not clear to me how to do this: I need to format to character a series of integers from 1 to 1000, and I like them to look like "0001" "0002", "0059", "0123" and so on. Padded with zeroes to have four digits. Cheers! Mario. r-help-request at r-project.org wrote: > Send