R: split-apply-combine for vectors, with equal-length outptu

do_by {validate} | R Documentation

## split-apply-combine for vectors, with equal-length outptu

### Description

Group `x` by one or more categorical variables, compute an aggregate, repeat that aggregate to match the size of the group, and combine results. The functions `sum_by` and so on are convenience wrappers that call `do_by` internally.

### Usage

    do_by(x, by, fun, ...)

    sum_by(x, by, na.rm = FALSE)

    mean_by(x, by, na.rm = FALSE)

    min_by(x, by, na.rm = FALSE)

    max_by(x, by, na.rm = FALSE)

### Arguments

`x` | A bare variable name
`by` | a bare variable name, or a list of bare variable names, used to split `x` into groups.
`fun` | `[function]` A function that aggregates `x` to a single value.
`...` | passed as extra arguments to `fun` (e.g. `na.rm=TRUE`
`na.rm` | Toggle ignoring `NA`

### See Also

Other cross-record-helpers: `contains_exactly()`, `exists_any()`, `hb()`, `hierarchy()`, `is_complete()`, `is_linear_sequence()`, `is_unique()`

### Examples

    x <- 1:10
    y <- rep(letters[1:2], 5)
    do_by(x, by=y, fun=max)
    do_by(x, by=y, fun=sum)

[Package validate version 1.1.1 Index]