如何在四个不同的数据框中添加相同列名的值，但列数不同答案

【问题标题】：How to add values of same column names across four different data frames but with different number of columns如何在四个不同的数据框中添加相同列名的值，但列数不同
【发布时间】：2018-08-16 21:40:59
【问题描述】：

我需要在 R 中的四个不同数据框中添加相同列名的值。问题是这 4 个数据框中的列数不同，其中只有一个数据框包含所有列。其余数据框具有第一个数据框的列名子集。 4 个数据帧的行数相等。

最小可复制示例是：

假设有4个数据框，结构如下：

df1 <- setNames(data.frame(matrix(ncol = 10, nrow = 900)), c("Red", "Blue", "Yellow", "Green", "Orange", "Pink", "Brown", "Black", "Grey", "Purple"))
df2 <- setNames(data.frame(matrix(ncol = 9, nrow = 900)), c("Red", "Blue", "Yellow", "Orange", "Pink", "Brown", "Black", "Grey", "Purple"))
df3 <- setNames(data.frame(matrix(ncol = 8, nrow = 900)), c("Red", "Blue", "Yellow", "Orange", "Pink", "Brown", "Black", "Purple"))
df4 <- setNames(data.frame(matrix(ncol = 6, nrow = 900)), c("Red", "Yellow", "Green", "Orange", "Brown", "Purple")

假设四个数据帧中的每一列都有跨越 900 行的整数值。如何返回一个数据框，它基本上是在四个数据框中添加相同列的值？换句话说，df.sum[1:10] <- df1[1:10] + df2[1:9] + df3[1:8] + df4[1:6]，但在添加时标识要添加的相同列

【问题讨论】：

你在做NA元素的总和？
不，我在所有 900 行中都有整数值

标签： r dataframe

【解决方案1】：

如果没有NA元素，我们可以在尺寸相同后做+

lst <- mget(paste0("df", 1:4)) # get the datasets in a list
nm1 <- Reduce(union, lapply(lst, names)) # find all the column names
# assign missing columns in each of the dataset with value 0
# get the `+` of all list elements with Reduce
dfout <- Reduce(`+`, lapply(lst, function(x) {
        x[setdiff(nm1, names(x))] <- 0
        x[nm1]}))
dim(dfout)
#[1] 900  10

数据

set.seed(24)
df1 <- setNames(data.frame(matrix(rnorm(900 * 10), ncol = 10, nrow = 900)), 
    c("Red", "Blue", "Yellow", "Green", "Orange", "Pink", 
  "Brown", "Black", "Grey", "Purple"))
df2 <- setNames(data.frame(matrix(rnorm(900 * 9), ncol = 9, nrow = 900)), 
   c("Red", "Blue", "Yellow", "Orange", "Pink", "Brown",
        "Black", "Grey", "Purple"))
df3 <- setNames(data.frame(matrix(rnorm(900 * 8), ncol = 8, nrow = 900)), 
      c("Red", "Blue", "Yellow", "Orange", "Pink", "Brown", "Black", "Purple"))
df4 <- setNames(data.frame(matrix(rnorm(900 * 6), ncol = 6, nrow = 900)),
     c("Red", "Yellow", "Green", "Orange", "Brown", "Purple"))

【讨论】：

做我想做的事！！