R: The Number of Levels of a Factor

nlevels {base} | R Documentation

## The Number of Levels of a Factor

### Description

Return the number of levels which its argument has.

### Usage

    nlevels(x)

### Arguments

`x` | an object, usually a factor.

### Details

If the argument is not a `factor`, `NA` is returned.

The actual factor levels (if they exist) can be obtained with the `levels` function.

### Examples

    nlevels(gl(3,7)) # = 3

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