is_leap_year {popEpi} | R Documentation |
Detect leap years
Description
Given a vector or column of year values (numeric or integer), [is_leap_year]
returns a vector of equal length
of logical indicators, i.e. a vector where corresponding leap years have value TRUE, and FALSE otherwise.
Usage
is_leap_year(years)
Arguments
years |
a vector or column of year values (numeric or integer) |
Value
A logical
vector where TRUE
indicates a leap year.
Author(s)
Joonas Miettinen
Examples
## can be used to assign new columns easily, e.g. a dummy indicator column
df <- data.frame(yrs=c(1900,1904,2005,1995))
df$lyd <- as.integer(is_leap_year(df$yrs))
## mostly it is useful as a condition or to indicate which rows have leap years
which(is_leap_year(df$yrs)) # 2
df[is_leap_year(df$yrs),] # 2nd row
[Package popEpi version 0.4.13 Index]