RinAction - R Functions - Applying Functions to R Objects

gistfile1.r

###################################################
### Apply Functions to Matrices and Data Frames ###
###################################################

# One of the interesting features of R functions is that they can be applied to a variety of
# data objects (scalars, vectors, matrices, arrays, and data frames).

b <- c(1.243, 5.654, 2.99)
round(b)

c <- matrix(runif(12), nrow=3)
c
log(c)
mean(c)


# Apply functions to any dimensions of an object using the apply() function
mydata <- matrix(rnorm(30), nrow=6)
mydata
apply(mydata, 1, mean)     # calculate row mean
apply(mydata, 2, mean)     # calculate column mean of the matrix
apply(mydata, 2, mean, trim=.2)  # calculate trimmed mean based on the middle 60% of data