ht {NNbenchmark}

Concatenates head() and tail() in vector, list, matrix, data.frame, array

Description

Concatenates head(n) and tail(n) rows and subset with m columns. Works also with array, list and matrix in data.frame. Keeps the data.table format (and add a timezone by default). See the matsindf package for matrix(ces) in tibble.

Usage

ht(x, n = 3, m = 4, p = 2, l = 2, names = TRUE, LTT = c("x", "L",
  "N", "M", "P", "Q", "R", "S", "T"))

ht9(x, n = 3, m = 9999, p = 2, l = 2, names = TRUE, LTT = c("x",
  "L", "N", "M", "P", "Q", "R", "S", "T"))

Arguments

x

vector, matrix, data.frame, array or list.

n

integer. Cut in the first dimension.

m

integer. Cut in the second dimension.

p

integer. Cut in the third and the next dimensions.

l

integer. Cut for a list and for data.frame with matrix inside.

names

logical. Provide names and numbers for undefined dimnames.

LTT

character. The letter used in each dimension (vector, list, array).

Value

An object of the same class than x but much shorter.

Examples

### Vector, data.frame, array
ht(1:100, names = FALSE)
ht(1:100, LTT = "z")

ht9(mtcars); dim(mtcars)

arr4 <- array(1:1680, c(8,7,6,5))
ht(arr4, n=1, p=1, names = FALSE)
ht(arr4, n=1, p=1, names = TRUE, LTT = c("x","L","X","Y","Z","T"))

### List of matrices
lstmat <- rep(list(matrix(1:100, 10)), 8)
for (i in seq_along(lstmat)) lstmat[[i]] <- lstmat[[i]] *i
lstmat
ht(lstmat, n = 2, m = 2, l = 2, names = FALSE)
ht(lstmat, n = 2, m = 3, l = 1, names = TRUE)
ht(lstmat, n = 2, m = 3, l = 1, LTT = c("x","L","X","Y","Z"))

### Data.frame with matrices inside.
### See For instance data("gasoline", package = "pls")

## Colnames on matrix B but not on matrix C. Protected data.frame.
B <- matrix(101:160, 10); colnames(B) <- paste0(1:6, "b"); B
C <- matrix(101:160, 10); C
dfrmat <- data.frame(A = 1:10, B = I(B), C = I(C), D = 11:20); dfrmat
colnames(dfrmat)

## Matrix columns are controlled by m.
## Unnamed C matrix columns have old values but new names. Be aware!
ht(dfrmat, n = 2, m = 1, l = 2, names = FALSE) # Original C.6 is now C.2
ht(dfrmat, n = 2, m = 1, l = 2, names = TRUE)  # Names keep original ranks

## Data.frame columns are controlled by l.
ht(dfrmat, n = 3, m = 2, l = 1, names = TRUE)