R: Generate Factor Levels

gl {base} | R Documentation

## Generate Factor Levels

### Description

Generate factors by specifying the pattern of their levels.

### Usage

    gl(n, k, length = n*k, labels = seq_len(n), ordered = FALSE)

### Arguments

`n` | an integer giving the number of levels.
`k` | an integer giving the number of replications.
`length` | an integer giving the length of the result.
`labels` | an optional vector of labels for the resulting factor levels.
`ordered` | a logical indicating whether the result should be ordered or not.

### Value

The result has levels from `1` to `n` with each value replicated in groups of length `k` out to a total length of `length`.

`gl` is modelled on the GLIM function of the same name.

### See Also

The underlying `factor()`.

### Examples

    ## First control, then treatment:
    gl(2, 8, labels = c("Control", "Treat"))
    ## 20 alternating 1s and 2s
    gl(2, 1, 20)
    ## alternating pairs of 1s and 2s
    gl(2, 2, 20)

[Package base version 3.1.2 Index]