R: Lump together least/most common factor levels into "other"

fct_lump {forcats} | R Documentation

## Lump together least/most common factor levels into "other"

### Description

Lump together least/most common factor levels into "other"

### Usage

    fct_lump(f, n, prop, w = NULL, other_level = "Other",
      ties.method = c("min", "average", "first", "last", "random", "max"))

### Arguments

`f` | A factor (or character vector).
`n, prop` | If both `n` and `prop` are missing, `fct_lump` lumps together the least frequent levels into "other", while ensuring that "other" is still the smallest level. It's particularly useful in conjunction with `fct_inorder()`. Positive `n` preserves the most common `n` values. Negative `n` preserves the least common `-n` values. It there are ties, you will get at least `abs(n)` values. Positive `prop` preserves values that appear at least `prop` of the time. Negative `prop` preserves values that appear at most `-prop` of the time.
`w` | An optional numeric vector giving weights for frequency of each value (not level) in f.
`other_level` | Value of level used for "other" values. Always placed at end of levels.
`ties.method` | A character string specifying how ties are treated. See `rank()` for details.

### See Also

`fct_other()` to convert specified levels to other.

### Examples

    x <- factor(rep(LETTERS[1:9], times = c(40, 10, 5, 27, 1, 1, 1, 1, 1)))
    x %>% table()
    x %>% fct_lump() %>% table()
    x %>% fct_lump() %>% fct_inorder() %>% table()

    x <- factor(letters[rpois(100, 5)])
    x
    table(x)
    table(fct_lump(x))

    # Use positive values to collapse the rarest
    fct_lump(x, n = 3)
    fct_lump(x, prop = 0.1)

    # Use negative values to collapse the most common
    fct_lump(x, n = -3)
    fct_lump(x, prop = -0.1)

    # Use weighted frequencies
    w <- c(rep(2, 50), rep(1, 50))
    fct_lump(x, n = 5, w = w)

    # Use ties.method to control how tied factors are collapsed
    fct_lump(x, n = 6)
    fct_lump(x, n = 6, ties.method = "max")

[Package forcats version 0.3.0 Index]