我想知道为什么R在迭代Date数组时将类Date转换为数字。
dates = as.Date(c("2017-01-01", "2017-01-02", "2017-01-03"))
for(i in 1:3) print(dates[i]) #Print Dates
[1] "2017-01-01"
[1] "2017-01-02"
[1] "2017-01-03"
for(d in dates) print(d) #Cast dates into numeric
[1] 17167
[1] 17168
[1] 17169