| split_by_NAs {exdex} | R Documentation |
Divides data into parts that contain no missing values
Description
Splits the values in a numeric matrix column-wise into sequences of non-missing values.
Usage
split_by_NAs(x)
Arguments
x |
A vector or matrix. |
Details
For each column in x, split_by_NAs finds runs of
values that contain no missing values and assigns them to a column in the
matrix that is returned. Different columns are treated separately.
If there are no missing values in a column then that column appears
unmodified in the output matrix. Please see the Examples
for illustrations.
Value
A matrix containing a column for each run of non-missing values in
x. The number of rows is equal to the longest run of non-missing
values in x and will therefore be at most nrow{x}. The
matrix is padded with NA values at the end of each column, where
necessary.
The returned object has an attribute called split_by_NAs_done
whose value is TRUE, so that in programming one can avoid calling
split_by_NAs more than once.
Examples
# Create a simple numeric matrix and insert some NAs
x <- matrix(1:50, 10, 5)
x[c(3, 8), 1] <- NA
x[c(1:2, 5, 10), 3] <- NA
x[1:3, 4] <- NA
x[7:10, 5] <- NA
x
res <- split_by_NAs(x)
res
# An example of a character matrix
x <- matrix(c(letters, letters[1:18]), 11, 4)
x[c(1:2, 5:11), 2] <- NA
x[c(2:4, 6:11), 3] <- NA
x[1:10, 4] <- NA
res <- split_by_NAs(x)
res