[R] Exact String Compare in R?

Dear R users: Here's a barebones example of what I can't make work. As you can see, regexpr() does not perform an exact string match, which only occurs in row 1 of these data frames. Instead, as it's supposed to do, it finds "b" in "bb" and "c" in "cc". Does anybody know what function I can use s

[R] exact string match?

Dear R users: I need to compare character strings stored in 2 separate data frames. I need an exact match, so finding "a" in "animal" is no good. I've tried regexpr, match, and grepl, but to no avail. Anybody know how to accomplish this? Ben -- View this message in context: http://old.nabble.c

[R] Data frame column name as function argument?

Any help is very much appreciated. The following is a toy example: > #1. Create a data frame with two named columns (x,y): > DF <- data.frame(cbind(x=1:5, y=6:10)) > DF x y 1 1 6 2 2 7 3 3 8 4 4 9 5 5 10 > #2. Define a function to compute the sum of a given column: > foo.fnc = function

[R] Syntax for crossed random effects in nlme

Hello R users, I've read the posts on this topic, and had a look at the R documentation for nlme, but I can't seem to make this work. I'd like to be able to fit a mixed effects model with crossed random effects, but also be able to specify the covariance matrix structure for the residuals. Here's

[R] Alternate error structures in lme4?

Hi R users, The nlme library enabled several alternate error structures useful for longitudinal or repeated-measures data. For example, a continuous AR(1) process: model_2 = update(model_1, correlation = corCAR1(form = ~ time | subject)) Does anybody know if this is available in lme4? Thank y