我正在尝试转换这个大型数据集日期列,这是格式(YYYY/MM/DD(,我希望简单地将"date"变量中的任何观测值转换为相应月份的第一天。2018/02/03 -> 2018/02/01( 我对数据表很陌生,所以如果这是一个简单的问题,请道歉。 这是我数据集的示例 dput((。
structure(list(quantity = c(NA_real_, NA_real_, NA_real_, NA_real_,
NA_real_, NA_real_), price_mid = c(NA_real_, NA_real_, NA_real_,
NA_real_, NA_real_, NA_real_), value_mid = c(100, 241.85, 241.85,
241.85, 241.85, 241.85), currency_price = c("GBP", "GBP", "GBP",
"GBP", "GBP", "GBP"), currency_value = c("GBP", "GBP", "GBP",
"GBP", "GBP", "GBP"), date = structure(c(13515L, 13516L, 13517L,
13518L, 13521L, 13522L), class = "Date")), class = c("data.table",
"data.frame"), row.names = c(NA, -6L), .internal.selfref = <pointer: 0x15f28c0>)
如果需要对此问题进行任何编辑,请告诉我。 谢谢
你可以像这样使用format
函数
data$date <- format(data$date,format = "%Y/%m/1")
> data
quantity price_mid value_mid currency_price currency_value date
1: NA NA 100.00 GBP GBP 2007/01/1
2: NA NA 241.85 GBP GBP 2007/01/1
3: NA NA 241.85 GBP GBP 2007/01/1
4: NA NA 241.85 GBP GBP 2007/01/1
5: NA NA 241.85 GBP GBP 2007/01/1
6: NA NA 241.85 GBP GBP 2007/01/1
如果你愿意,你可以完全放弃这一天,它可能更具代表性。
data$date <- format(data$date,format = "%Y/%m")
> data
quantity price_mid value_mid currency_price currency_value date
1: NA NA 100.00 GBP GBP 2007/01
2: NA NA 241.85 GBP GBP 2007/01
3: NA NA 241.85 GBP GBP 2007/01
4: NA NA 241.85 GBP GBP 2007/01
5: NA NA 241.85 GBP GBP 2007/01
6: NA NA 241.85 GBP GBP 2007/01