r - 从循环创建数据框

Question

如何为 wkend 创建数据框而不是不打印它？

wkend<-as.Date(c("2013-01-04","2013-01-05","2013-01-06"),"%Y-%m-%d")
while(wkend < "2013-12-27") { 
   wkend <- wkend + 7
print(wkend)
 }

Answer 1

如果你想有一个data.frame，你需要将最后一天调整一个否则你会有不均匀的行。但是你可以使用 lapply申请 seq.Date对您 wkend 中的每个元素起作用像这样的向量:

df <- data.frame( lapply( wkend , seq , to = as.Date( "2013-12-26" , "%Y-%m-%d" ) , by = 7 ) )
names( df ) <- c("Col1","Col2","Col3") # Call the columns whatever you want
head(df)
    Col1       Col2       Col3
1 2013-01-04 2013-01-05 2013-01-06
2 2013-01-11 2013-01-12 2013-01-13
3 2013-01-18 2013-01-19 2013-01-20
4 2013-01-25 2013-01-26 2013-01-27
5 2013-02-01 2013-02-02 2013-02-03
6 2013-02-08 2013-02-09 2013-02-10