For 1,000,000 observations, I observed a discrete event, X, 3 times for the control group and 10 times for the test group. I need to preform a Chi square test of independence in Matlab. This is how you would do it in r: m <- rbind(c(3, 1000000-3), c(10, 1000000-10)) # [,1] [,2] # [1,] 3 999997 # [2,] 10 999990 chisq.test(...
I'm using reshape in R to compute aggregate statistics over columns of a data.frame. Here's my data.frame: > df a a b b ID 1 1 1 1 1 1 2 2 3 2 3 2 3 3 5 3 5 3 which is just a little test data.frame to try and understand the reshape package. I melt, and then cast, to try and find the mean of the as and the bs: > melt(df, id = "ID...
Another rather basic question for which I can't find a definitive answer online: I have a data frame containing (in random places) a character value (say "foo")that I want to replace with a NA. What's the best way to do so across the whole data frame? Thanks, Roberto ...
I noticed that in the library folder of my Revolution R installation that there are some packages unique to Revolution. So I copied them to my regular R distribution and those packages worked fine. Can I use the Revolution packages free of charge in a commercial environment? My understanding is that anyone who contributes to R needs to...
As a recent graduate, I was considering doing some freelance data analysis work. While there are numerous firms offering similar services, I would direct my services towards small "mom and pop" business and the self-employed. Does anyone have experiance with this? What's been your experiance? ...
I would like to use Perl to take a previously generated SPSS syntax file and format it for use in an R environment. This is probably a very simple task for those familiar with Perl and regex, but I am stumbling. The steps as I've laid them out for this Perl script are as follows: Read in SPSS file Find appropriate chunks of SPSS fil...
In a loop, I am trying to get a column vector of class factor into numeric. If there were not a loop, the code would look like c1$values <- as.numeric(as.character(c1$values)) But how do I reference c1$values with a loop? I have tried two approaches: get(paste('c',i,"$values", sep="")) just does not work even outside the loop, wh...
I have an array with dates as indices which I'm plotting. I'd like to plot a LOESS curve along with it. However, the input for loess is a formula. Is there a good way to define a formula from array index to value which I can then give to the loess function? ...
Hi, Is this method broken in R? I am using it to find roots of the following function: f(x) = 2.5*exp(-0.5*(2*0.045 - x)) + 2.5*exp(-0.045) + 2.5*exp(-1.5*x) - 100 It is giving an answer of -38.4762403 which is not even close (f(x) = 2.903809e+25 for x=-38.4762403). The answer should be around 0.01-0.1. This function should converge.. ...
I have this for(i in 1:10) and within it, I have a data frame: e.g. df<-1:100 and I want to assign the dataframe to a specific name which I want to create something like: (not that it works) paste("name", variable[i])<- df Edit: How would I then go about accessing those constructed values in another loop (assuming i've us...
Hi everyone, I use SPSS everyday but have really been trying to learn R. The major thing that is holding me back is my need to easily generate tables, banners, and cross-tabs for the market research that I do. I love the Custom Tables option in SPSS and am looking for advice on how to replicate it with R. I believe R has a ton of adv...
I want to save the R output to a specific place, but what I want to do is add the time and day to the file(according to the system time). 29-Jul-2010 15.35.txt anyway to do it? I know about Sys.time and date() but they both contain : which windows xp doesn't like. ...
What is a good library for wavelets in R? ...
In a loop, I am trying to perform a simple renaming of the variables in a df. Without the loop, this works perfectly: names(c1) <- c("sales", "month") With a loop-friendly approach ("1" in place of i in the dry-run example) the following correctly references names(c1): names(get(paste("c","1", sep=""))) but as I write the whole op...
Hello, I need to remove the ticks and major line from a generated axis using grid.yaxis. According to ?grid.yaxis there is an "edits" parameter that will let me configure the "major", "ticks" and "labels". However, I cant find how to use the edits parameter. Here's some example code that will draw an axis in the center. grid_test_axi...
When I run R scripts I go do something else on a different desktop. If I don't check frequently, I never know when something is finished. Is there a way to invoke a beep (like a system beep) or get R to play a sound or notify growl via some code at the end of my script? ...
I have a list of vectors which are time series of inequal length. My ultimate goal is to plot the time series in a ggplot2 graph. I guess I am better off first merging the vectors in a dataframe (where the shorter vectors will be expanded with NAs), also because I want to export the data in a tabular format such as .csv to be perused by ...
How can I make sqlSave to write only a subset of columns. I've a (MS-Access) table with e.g. columns A, B, C en D and if I send a sqlSave command with a data frame with columns A, B en D (no C) I get the message: Error in odbcUpdate(channel, query, mydata, coldata[m, ], test = test, : missing columns in 'data' Calls: sqlSave -> sqlw...
I am looking to extract the p-value generated from an anova in R. Here is what I am running: test <- aov(asq[,9] ~ asq[,187]) summary(test) Yields: Df Sum Sq Mean Sq F value Pr(>F) asq[, 187] 1 3.02 3.01951 12.333 0.0004599 *** Residuals 1335 326.85 0.24483 --- Signif. codes: 0 ...
I'm trying to calculate asset-weighted returns by asset class. For the life of me, I can't figure out how to do it using the aggregate command. My data frame looks like this dat <- data.frame(company, fundname, assetclass, return, assets) I'm trying to do something like (don't copy this, it's wrong): aggregate(dat, list(dat$asset...