Convert dates encoded as serial numbers to Date class.
Source:R/excel_dates.R
excel_numeric_to_date.Rd
Converts numbers like 42370
into date values like 2016-01-01
.
Defaults to the modern Excel date encoding system. However, Excel for Mac 2008 and earlier Mac versions of Excel used a different date system. To determine what platform to specify: if the date 2016-01-01 is represented by the number 42370 in your spreadsheet, it's the modern system. If it's 40908, it's the old Mac system. More on date encoding systems at http://support.office.com/en-us/article/Date-calculations-in-Excel-e7fe7167-48a9-4b96-bb53-5612a800b487.
A list of all timezones is available from base::OlsonNames()
, and the
current timezone is available from base::Sys.timezone()
.
If your input data has a mix of Excel numeric dates and actual dates, see the
more powerful functions convert_to_date()
and convert_to_datetime()
.
Usage
excel_numeric_to_date(
date_num,
date_system = "modern",
include_time = FALSE,
round_seconds = TRUE,
tz = Sys.timezone()
)
Arguments
- date_num
numeric vector of serial numbers to convert.
- date_system
the date system, either
"modern"
or"mac pre-2011"
.- include_time
Include the time (hours, minutes, seconds) in the output? (See details)
- round_seconds
Round the seconds to an integer (only has an effect when
include_time
isTRUE
)?- tz
Time zone, used when
include_time = TRUE
(see details for more information on timezones).
Value
Returns a vector of class Date if include_time
is
FALSE
. Returns a vector of class POSIXlt if include_time
is
TRUE
.
Details
When using include_time=TRUE
, days with leap seconds will not
be accurately handled as they do not appear to be accurately handled by
Windows (as described in
https://support.microsoft.com/en-us/help/2722715/support-for-the-leap-second).
See also
Other date-time cleaning:
convert_to_date()
,
excel_time_to_numeric()
,
sas_numeric_to_date()
Examples
excel_numeric_to_date(40000)
#> [1] "2009-07-06"
excel_numeric_to_date(40000.5) # No time is included
#> [1] "2009-07-06"
excel_numeric_to_date(40000.5, include_time = TRUE) # Time is included
#> [1] "2009-07-06 12:00:00 UTC"
excel_numeric_to_date(40000.521, include_time = TRUE) # Time is included
#> [1] "2009-07-06 12:30:14 UTC"
excel_numeric_to_date(40000.521,
include_time = TRUE,
round_seconds = FALSE
) # Time with fractional seconds is included
#> [1] "2009-07-06 12:30:14 UTC"