问题
In the R package reshape2, does the dcast() function parameter fun.aggregate= have the ability to accept parameters itself?
For instance:
dcast(dataFrame, x ~ y, value.var = 'z', fun.aggregate = mean(na.rm = TRUE))
I'm asking because I use my own function for the fun.aggregate parameter, and I'd rather not hard code the parameters into a growing list of functions.
This website is great; thanks everyone.
回答1:
Like many functions in R, dcast has a ... argument that is typically used to pass additional arguments on to a function. In fact, at ?dcast, you'll find this line in the "arguments section":
...further arguments are passed to aggregating function
Thus, the correct way of writing your example would be:
dcast(dataFrame, x ~ y, value.var = 'z', fun.aggregate = mean, na.rm = TRUE)
来源：https://stackoverflow.com/questions/19732640/dcast-fun-aggregate-parameters