Locate period boundaries for a date vector
warp_boundary() detects a change in time period along x, for example,
rolling from one month to the next. It returns the start and stop positions
for each contiguous period chunk in x.
warp_boundary(x, period, ..., every = 1L, origin = NULL)
x |
A date time vector. |
period |
A string defining the period to group by. Valid inputs can be roughly broken into:
|
... |
These dots are for future extensions and must be empty. |
every |
The number of periods to group together. For example, if the period was set to |
origin |
The reference date time value. The default when left as This is generally used to define the anchor time to count from, which is
relevant when the every value is |
The stop positions are just the warp_change() values, and the start
positions are computed from these.
A two column data frame with the columns start and stop. Both are
double vectors representing boundaries of the date time groups.
x <- as.Date("1970-01-01") + -4:5
x
# Boundaries by month
warp_boundary(x, "month")
# Bound by every 5 days, relative to "1970-01-01"
# Creates boundaries of:
# [1969-12-27, 1970-01-01)
# [1970-01-01, 1970-01-06)
# [1970-01-06, 1970-01-11)
warp_boundary(x, "day", every = 5)
# Bound by every 5 days, relative to the smallest value in our vector
origin <- min(x)
origin
# Creates boundaries of:
# [1969-12-28, 1970-01-02)
# [1970-01-02, 1970-01-07)
warp_boundary(x, "day", every = 5, origin = origin)Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.