R: Cast a duration between precisions

duration_cast {clock} | R Documentation

## Cast a duration between precisions

### Description

Casting is one way to change a duration's precision.

Casting to a less precise precision will completely drop information that is more precise than the precision that you are casting to. It does so in a way that makes it round towards zero.

Casting to a more precise precision is done through a multiplication by a conversion factor between the current precision and the new precision.

### Usage

    duration_cast(x, precision)

### Arguments

`x` | `[clock_duration]` A duration.
`precision` | `[character(1)]` A precision. One of: `"year"` `"quarter"` `"month"` `"week"` `"day"` `"hour"` `"minute"` `"second"` `"millisecond"` `"microsecond"` `"nanosecond"`

### Details

When you want to change to a less precise precision, you often want `duration_floor()` instead of `duration_cast()`, as that rounds towards negative infinity, which is generally the desired behavior when working with time points (especially ones pre-1970, which are stored as negative durations).

### Value

`x` cast to the new `precision`.

### Examples

    x <- duration_seconds(c(86401, -86401))

    # Casting rounds towards 0
    cast <- duration_cast(x, "day")
    cast

    # Flooring rounds towards negative infinity
    floor <- duration_floor(x, "day")
    floor

    # Flooring is generally more useful when working with time points,
    # note that the cast ends up rounding the pre-1970 date up to the next
    # day, while the post-1970 date is rounded down.
    as_sys_time(x)
    as_sys_time(cast)
    as_sys_time(floor)

    # Casting to a more precise precision
    duration_cast(x, "millisecond")

[Package clock version 0.4.1 Index]