seq_along_dim {listarrays}

Sequence along a dimension

Description

Sequence along a dimension

Usage

seq_along_dim(x, which_dim)

seq_along_rows(x)

seq_along_cols(x)

Arguments

x

a dataframe, array or vector. For seq_along_rows, and seq_along_cols sequence along the first and last dimensions, respectively. Atomic vectors are treated as 1 dimensional arrays (i.e., seq_along_rows is equivalent to seq_along when x is an atomic vector or list).

which_dim

a scalar integer or character string, specifying which dimension to generate a sequence for. Negative numbers count from the back.

Value

a vector of integers 1:nrow(x), safe for use in for loops and vectorized equivalents.

Examples

for (r in seq_along_rows(mtcars[1:4,]))
  print(mtcars[r,])

x <- 1:3
identical(seq_along_rows(x), seq_along(x))