R language-converts string data into DateTime, week, month, etc., including build date _r language

#假设已经有字符串如下:

D1<-c ("2011-01-02", "2011-01-09", "2011-01-16", "2011-01-23", "2011-01-30"
, "2011-02-06", "2011-02-13", "2011-02-20", "2011-02-27", "2011-03-06"
, "2011-03-13", "2011-03-20", "2011-03-27", "2011-04-03", "2011-04-10"
, "2011-04-17", "2011-04-24", "2011-05-01", "2011-05-08", "2011-05-15"
, "2011-05-22", "2011-05-29", "2011-06-05", "2011-06-12", "2011-06-19"
, "2011-06-26", "2011-07-03", "2011-07-10", "2011-07-17", "2011-07-24"
, "2011-07-31", "2011-08-07")

#转换成日期:

Dmonth<-as. Date (D1, "%y-%m-%d") #有的人日期喜欢写成 "2011/07/31", this time only need to change to/that as. Date (D1, "%y/%m/%d")

#转换成星期, Month:

Month1<-months (Dmonth) #转化为月份
Week1<-weekdays (Dmonth) #转化为星期

#时间比较 (in fact, R automatically sorted the time, interested students can try this sentence as.numeric (dmonth) < convert time into data, can be counted as R is the day as the first day of >)

#假如说 already have dataset data

Data1<-data[dmonth<= "2011-12-30"] #提取数据集data中11年之前的数据

#生成日期数据

#刚才说了怎么将时间转为数字, it must be possible to convert numbers to dates in turn.

D2<-as. Date (23768, origin = "1900-01-01") #感兴趣的朋友可以知道R的origin是多少了吧.

#利用seq函数

date1<-seq (from=as. Date (' 2006/01/01 '), To=as. Date (' 2016/08/03 '), by= ' 1 day ') #想生成月度或者星期, just replace day with month or week

#返回当前日期或系统时间:

Sys.date () #日期

Date () #具体时间