as.hour: Convert date-time object into hour units
In epitools: Epidemiology Tools

Description Usage Arguments Details Value Author(s) References See Also Examples

Convert date-time object into hour or half-hour units

1	as.hour(x, mindt, maxdt, half.hour = FALSE)

`x`	Date-time object in standard format: for example, "2004-12-23 08:27:00", "2004-12-23 08:27", "2004-12-23"
`mindt`	[required] Date-time object in standard format that will form the lower boundary of the hour or half-hour time categories. `mindt` must less than or equal to the minimum value in `x`, and must be rounded off to the nearst hour for hour categories (e.g., HH:00:00) or rounded off to the nearest half-hour for half-hour categories (e.g., HH:30:00).
`maxdt`	[required] Date-time object in standard format that will form the upper boundary of the hour or half-hour time categories. `maxdt` must greater than or equal to the minimum value in `x`, and must be rounded off to the nearst hour for hour categories (e.g., HH:00:00) or rounded off to the nearest half-hour for half-hour categories (e.g., HH:30:00).
`half.hour`	Set to TRUE for half-hour categories.

This function (1) converts standard date-time objects into 1-hour or 1/2-hour categories, and (2) generates levels for range of values that that the new 1-hour or 1/2-hour categories can take. These levels are use for converting x into a factor and for providing names for labeling the x-axis in plot. This function is used by epicurves.hours.

`$ct`	Date-time object that contains the number of seconds since the beginning of 1970 as a numeric vector and produced by `as.POSIXct`. You can use `as.POSIXlt` to convert this output in human legible (already done by this function).
`$sec`	seconds
`$min`	minutes
`$hour`	hours (0-23)
`$hour12`	hours (1-12)
`$stratum`	number of hours or 1/2 hours since beginning of 1970
`$stratum2`	factor (categorical variable) with number of hours of 1/2 hours since beginning of 1970 using `$cstratum` as the levels
`$stratum3`	factor (categorical variable) in standard date-time format indicating number of hours or 1/2 hours since beginning of 1970 using `$cstratum2` as the levels
`$cstratum`	levels for creating `$stratum2` factor
`$cstratum2`	levels for creating `$stratum3` factor
`$csec`	seconds from `$cstratum2`
`$cmin`	minutes from `$cstratum2`
`$chour`	hours from `$cstratum2` in 24-hour format
`$chour12`	hours from `$cstratum2` in 12-hour format
`$campm`	corresponding 'AM' or 'PM' for `$chour12`
`$campm2`	corresponding 'am' or 'pm' for `$chour12`
`$cweekday`	day of the week for `$cstratum2`
`$cwkday`	abbreviated day of the week for `$cstratum2`
`$cmday`	day of the month for `$cstratum2`
`$cmonth`	month for `$cstratum2`
`$cmon`	abbreviated month for `$cstratum2`
`$cyear`	year for `$cstratum2`
`$half.hour`	FALSE (default) for 1-hour categories; TRUE for 1/2-hour categories

Tomas Aragon, aragon@berkeley.edu, http://www.phdata.science

none

epitools: as.month, epicurve.dates

as.Date, strptime, DateTimeClasses

dates <- c("1/1/04", "1/2/04", "1/3/04", "1/4/04", "1/5/04",
"1/6/04", "1/7/04", "1/8/04", "1/9/04", "1/10/04", NA, "1/12/04",
"1/14/04", "3/5/04", "5/5/04", "7/6/04", "8/18/04", "12/13/05",
"1/5/05", "4/6/05", "7/23/05", "10/3/05")
aw <- as.week(dates, format = "%m/%d/%y")
aw

aw2 <- as.week(dates, format = "%m/%d/%y", sunday= FALSE)
aw2

aw3 <- as.week(dates, format = "%m/%d/%y", min.date="2003-01-01")
aw3