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rdateif-statement
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Reputation: 381

if statement with dates in R - generalizing per year

I start from the following question to seek generalization properties: if statement with dates in R

df <- data.frame(date = as.Date(c("16.04.2015", "04.08.2014", "11.09.2013",
                                  "20.11.2015", "04.04.2014"), '%d.%m.%Y'))

I want to identify all the dates between 07-15 (%m-%d) and 12-31, e.g.

> date        value
> 16.04.2015  0
> 04.08.2014  1
> 11.09.2013  1
> 20.11.2015  1
> 04.04.2014  0

My solution is based on a solution by @rawr posted in the above question:

Function for the interval:

`%between%` <- function(x, interval) x >= interval[1] & x <= interval[2]

vector with all the possible beginning:

begi <- as.Date(sprintf('%s-07-15',1993:2018))

# Vector with all the possible intervals
dates <- as.Date(c(sprintf('%s-07-15',1993:2018), sprintf('%s-12-31',1993:2018)))

Loop using the function

df$value <- NA

for (i in length(begi)) {
  ind<-which(format(df$date,"%Y") == format(begi[i], "%Y"))
  df$value[ind] <- 1*(df$date[ind] %between% as.Date(c(begi[i], 
                dates[i+length(begi)])))
}

If I ran the i one by one I obtain the wanted result. However, if I ran the loop the last i, it overwrites the entire column instead of using only the position indicated by ind. Why?

Upvotes: 1

Views: 269

Answers (2)

IceCreamToucan
IceCreamToucan

Reputation: 28675

You can format your dates as %m-%d and use string comparison

df$value <- as.numeric(format(df$date, '%m-%d') %between% c('07-15', '12-31'))
df
#         date value
# 1 2015-04-16     0
# 2 2014-08-04     1
# 3 2013-09-11     1
# 4 2015-11-20     1
# 5 2014-04-04     0

Upvotes: 1

12b345b6b78
12b345b6b78

Reputation: 1015

df$leapyear <- ifelse(as.integer(format(df$date, "%Y")) %% 4 == 0, 1, 0)
df$leapyear <- ifelse(as.integer(format(df$date, "%Y")) %% 100 == 0, 0, 1)
df$leapyear <- ifelse(as.integer(format(df$date, "%Y")) %% 400 == 0, 1, 0)

df[format(df$date, "%j") > ifelse(df$leapyear == 0, 197, 196), ]

thanks to @RyanD for pointing out that subsetting based on day of year fails to take leap years into account

Upvotes: 0

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