r - R删除条目不是日期的行

Question

我有一个数据框，其中一列是（意味着）表单中的日期00:00:00.0 yyyy-mm-dd。大多数条目是，但有些不是。有没有办法删除包含非日期的行？类似的东西（如果列是“日期”）

data <- data[is.Date(DATE)==TRUE,]

例如。

Fruit  Date
apple  00:00:00.0 2005-02-01
pear   00:00:00.0 2006-02-01
orange 00:00:00.0 -8-2-402145
rhino  00:00:00.0 2003-04-21

我想

Fruit  Date
apple  00:00:00.0 2005-02-01
pear   00:00:00.0 2006-02-01
rhino  00:00:00.0 2003-04-21

Answer 1

按照joran的推理：

# get the test data
test <- data.frame(
    Fruit=c("apple","pear","orange","rhino"),
    Date=c("00:00:00.0 2005-02-01",
           "00:00:00.0 2006-02-01",
           "00:00:00.0 -8-2-402145",
           "00:00:00.0 2003-04-21")
)

# remove the rows by checking if not (!) an NA due to not meeting the date format
test[!is.na(strptime(test$Date,format="00:00:00.0 %Y-%m-%d")),]

结果：

  Fruit                  Date
1 apple 00:00:00.0 2005-02-01
2  pear 00:00:00.0 2006-02-01
4 rhino 00:00:00.0 2003-04-21