You can specify default settings for MySQL in the file ~/.my.cnf (create it if it doesn’t exist). E.g., you could spare yourself typing your password each time you connect with an entry in that file like this:
[client] password='mypassword'
This gets loaded in addition to the system configuration file, which for me is at /etc/mysql/my.cnf.
Memo to self: I installed RMySQL using
sudo aptitude install r-cran-rmysql
because when I used
install.packages("RMySQL")
it asked my to specify the MySQL libraries and headers and whatnot and don’t know where they are.
When you start using R, it can be confusing that if you assign something to an object you do not get visual feedback:
x <- rep(1:3,5)
You have to then type x to see it:
> x [1] 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3
You can exploit this fact for doing a quick-and-dirty lottery. Assume you have a file with email addresses, one per line, called "entries.txt". First, read them and assign them to an object:
entries <- readLines("entries.txt")
Next, create an index of numbers of the same length but in random order:
index <- sample(1:length(entries),length(entries))
Note that you don't see it unless you type index. Combine index and emails in a dataframe (also not directly visible):
dat <- data.frame(cbind(index,entries))
Now, go to random.org and draw a number from the index. Type dat to reveal who you drew. This method makes it a bit more "blind" and a bit less likely that you'll cheat.
For the record. I got an error running hyperref:
Paragraph ended before \Hy@setref@link was complete
This was due to having a regulare closing parenthesis directly after the curly bracket that closed a \ref, like this: (see section \ref{section-1}). Putting in a space between the closing curly bracket and parenthesis solved the problem: ... section-1} )
I don’t know the first thing about programming, but sometimes you see something and appreciate how elegant it is. This small solution from r-help is a good example. Someone wanted, given a vector c('p','p','t','t','t','p','k','t') to produce NA NA 1 2 3
test <- c('p','p','t','t','t','p','k','t')
v <- cumsum(ind <- test == 't')
v[!ind] <- NA
I didn't know you could assign something to an object and use it at the same time. Very neat. So if you wanted this all at once, you could also do:
v <- ifelse(cumsum(ind <- test=='t')==0,NA,cumsum(ind))
or
ifelse((v <- cumsum(test=='t'))==0,NA,v)
Maybe Dimitris' solution is in fact preferred for R, using indexing instead of if/ else, but I don't know enough about R to know whether that makes a difference.