小编MHN*_*MHN的帖子

我希望按名称聚合数据框的两列,具体方法如下:

• 掉落parts的特殊聚集两列的结果列fruits和parts
• 虽然parts苹果,香蕉和草莓的价值无关紧要,一切都得到了总结,但parts葡萄和新西兰的价值应该成为新的fruits名字
• 结果(在底部)应该有8个聚合行而不是20个

这听起来似乎很简单,但经过数小时的试验和错误,我没有找到任何有用的解决方案.这是一个例子:

theDF <- data.frame(dates = as.Date(c(today()+20)),
    fruits = c("Apple","Apple","Apple","Apple","Banana","Banana","Banana","Banana",
      "Strawberry","Strawberry","Strawberry","Strawberry","Grape", "Grape",
      "Grape","Grape", "Kiwi","Kiwi","Kiwi","Kiwi"),
    parts = c("Big Green Apple","Apple2","Blue Apple","XYZ Apple4",
      "Yellow Banana1","Small Banana","Banana3","Banana4",
      "Red Small Strawberry","Red StrawberryY","Big Strawberry",
       "StrawberryZ","Green Grape", "Blue Grape", "Blue Grape",
       "Blue Grape","Big Kiwi","Small Kiwi","Big Kiwi","Middle Kiwi"),
    stock = as.vector(sample(1:20)) )      

当前数据框:

所需的输出: