Modify columns in a data frame in R more cleanly - maybe using with() or apply()?
- by Mittenchops
I understand the answer in R to repetitive things is usually "apply()" rather than loop. Is there a better R-design pattern for a nasty bit of code I create frequently?
So, pulling tabular data from HTML, I usually need to change the data type, and end up running something like this, to convert the first column to date format (from decimal), and columns 2-4 from character strings with comma thousand separators like "2,400,000" to numeric "2400000."
X[,1] <- decYY2YY(as.numeric(X[,1]))
X[,2] <- as.numeric(gsub(",", "", X[,2]))
X[,3] <- as.numeric(gsub(",", "", X[,3]))
X[,4] <- as.numeric(gsub(",", "", X[,4]))
I don't like that I have X[,number] repeated on both the left and ride sides here, or that I have basically the same statement repeated for 2-4.
Is there a very R-style way of making X[,2] less repetitive but still loop-free? Something that sort of says "apply this to columns 2,3,4---a function that reassigns the current column to a modified version in place?"
I don't want to create a whole, repeatable cleaning function, really, just a quick anonymous function that does this with less repetition.
