按天省略在年初和年末的日期

Question

I'm trying to get the total number of observations with a certain color associated.

Date <- c("2017-01-01","2017-01-01","2017-01-02","2017-01-03","2017-01-03","2017-01-03","2017-01-03","2017-01-04","2017-01-04","2017-01-05")

Factor<-c("red", "blue", "green", "red", "red", "green", "green", "blue", "blue", "green")

A different table for each of the factors. They should all have one row for each day of the year and the total number of observations.

green <-  table(cut(ex$Date[which(ex$Factor=="green")], 'day'))

It somehow works, but not perfectly. If there is no observation for 01.01.2017 and there is one for 02.01.2017 it will start the List with 02.01.2017. The data set is for one year. The same problem appears at the end of the year (eg 31.12.2017, 30.12.2017,... being omitted).

2017-01-02   1
2017-01-03   2
2017-01-04   0
2017-01-05   1

Does anyone have an idea how I can solve this?

Answer 1

Here is one base R option using aggregate :

df <- data.frame(Date, Color, stringsAsFactors=FALSE)
aggregate(df$Color, by=list(Date=df$Date), FUN=function(x) { sum(x=="green") })

        Date x
1 2017-01-01 0
2 2017-01-02 1
3 2017-01-03 2
4 2017-01-04 0
5 2017-01-05 1

Data:

Date <- c("2017-01-01","2017-01-01","2017-01-02","2017-01-03","2017-01-03","2017-01-03",
    "2017-01-03","2017-01-04","2017-01-04","2017-01-05")
Color <- c("red", "blue", "green", "red", "red", "green", "green", "blue", "blue", "green")