如何在R中解释data.frame

Question

I have problem in interpret the following syntax:

data=data.frame(X,Z[,5])

I check it in R. I konw that X is the dataset that pass to the data.fram, but I don't find the corresoponding argument to Z[,5] , so how to interpret this syntax?

data.frame(..., row.names = NULL, check.rows = FALSE,
           check.names = TRUE, fix.empty.names = TRUE,
           stringsAsFactors = default.stringsAsFactors())

Answer 1

X and Z[,5] are both being passed as data values through the ... argument. An attempt will be made to make both of them into separate columns of a data frame. Any arguments that follow ... in an argument list must be named. In data.frame() , ... is the first argument. So to pass values to any argument other than ... , you must use names. You haven't named any, and therefore both X and Z[,5] are passed to ... . If you had done, for example,

data.frame(X, row.names = Z[,5]) 

where there is a named argument, then Z[,5] would be passed to the row.names argument. See the Introduction to R manual for more.