duration_cast {clock} | R Documentation |
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.
duration_cast(x, precision)
x |
A duration. |
precision |
A precision. One of:
|
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).
x
cast to the new precision
.
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")