R: Cast a time point between precisions

time_point_cast {clock} | R Documentation

## Cast a time point between precisions

### Description

Casting is one way to change a time point'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. When converting time points to a less precise precision, you often want `time_point_floor()` instead of `time_point_cast()`, as that handles pre-1970 dates (which are stored as negative durations) in a more intuitive manner.

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

### Usage

    time_point_cast(x, precision)

### Arguments

`x` | `[clock_sys_time / clock_naive_time]` A sys-time or naive-time.
`precision` | `[character(1)]` A time point precision. One of: `"day"` `"hour"` `"minute"` `"second"` `"millisecond"` `"microsecond"` `"nanosecond"`

### Value

`x` cast to the new `precision`.

### Examples

    # Hour precision time points
    # One is pre-1970, one is post-1970
    x <- duration_hours(c(25, -25))
    x <- as_naive_time(x)
    x

    # Casting rounds the underlying duration towards 0
    cast <- time_point_cast(x, "day")
    cast

    # Flooring rounds the underlying duration towards negative infinity,
    # which is often more intuitive for 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.
    floor <- time_point_floor(x, "day")
    floor

    # Casting to a more precise precision, hour->millisecond
    time_point_cast(x, "millisecond")

[Package clock version 0.5.0 Index]