Vector operations

vector_operations.r

# http://stackoverflow.com/questions/7706876/r-script-removing-na-values-from-a-vector
# Sort vectors that have 'NA'

d <- c(1, 100, NA, 10)
max(d, na.rm=TRUE)

# Remove 'NA' in a vector

d <- d[!is.na(d)]
na.omit(d)

# http://stackoverflow.com/questions/3413879/how-to-create-an-empty-r-vector-to-add-new-items
# Create empty vector

d <- vector()

d <- rep(NA, 10) # preallocate a vector with

d <- {}

d <- c()

d <- NULL

# http://stackoverflow.com/questions/4570537/vectorizing-a-matrix
# create a vector from matrix

m <- matrix(1:9,3)

c(m)

as.vector(m)


# http://stackoverflow.com/questions/2545228/converting-a-dataframe-to-a-vector-by-rows
# convert a data frame to vector

d <- data.frame(x=c(26,21,20),y=c(34,29,28))

v <- c(t(d)) # t implicitly converts data frame to matrix 

v <- as.vector(t(d))

v <- as.vector(as.matrix(d)) # convert by column