合并 r 中的两个数据帧（更新和删除值）答案

【问题标题】：Merge two data frames in r (updating and dropping values)合并 r 中的两个数据帧（更新和删除值）
【发布时间】：2016-10-20 06:59:33
【问题描述】：

我有两个数据框：

data <- data.frame(ID1 = c("D1","D1","D1","D1","D2","D2"),
               ID3 = c("A","A","D","D","B","C"),
               Attribute = c("KL","KM","KL","KM","AB","AB"),
               Value = c(2,2,3,3,5,7))


data_new <- data.frame(ID1 = c("D1","D1","D2","D2"),
               ID2 = c("D1-1","D1-1","D2-1","D2-1"),
               Attribute = c("KL","TA","AB","AA"))

现在我想将数据中的Values 和ID3 合并到我的新数据框中。此外，我想删除一些属性并添加新属性。输出应如下所示：

expected_output <- data.frame(ID1 = c("D1","D1","D1","D1","D2","D2","D2","D2"),
                          ID2 = c("D1-1","D1-1","D1-1","D1-1","D2-1","D2-1","D2-1","D2-1"),
                          ID3 = c("A","A","D","D","B","B","C","C"),
                          Attribute = c("KL","TA","KL","TA","AB","AA","AB","AA"),
                          Value = c(2,2,3,3,5,5,7,7))

谁能帮我解决这个问题？

到目前为止，我尝试的是一个简单的合并。

mergeddata <- merge(data_new,data, 
                by.x = c("ID1"),
                by.y = c("ID1"))

ID1 = D2 的结果看起来很有希望我只需要删除列 Attribute.x"。但是 ID = D1 不是我想要的。第 5-8 行不应再出现在新表中。

有什么帮助吗？

【问题讨论】：

不清楚您要做什么。从data和data_new到expected_output的思路是什么？
假设 ID1 是基金 (ID3) 中的一种证券，该证券 (ID1) 具有一些属性，每个基金都有一个价值（头寸）。现在证券的属性发生了变化 (data_new) 并且他们获得了一个基于 ID1 的新 ID (ID2)。目标是使用新属性更新数据，但保留位置和值。是不是更清楚了？

标签： r dataframe merge

【解决方案1】：

我认为您可以尝试以下方法：

mergeddata <- merge(data_new ,unique(data[, c("ID1", "ID3", "Value")]), by = "ID1")

【讨论】：