在列表的两个元素中捕获值的不相等 [英] Capture non-equality of values in two elements of a list

问题描述

我想创建 if()条件以捕获 list()的 x 元素中的值不完全相同的情况 list()的 y 元素中的 OR 值在两种情况下都不都是相同的 OR .

I want to create if() conditions to capture when values in the x element of a list() are not all the same OR values in the y element of a list() are not all the same OR both situations together.

为具体起见，我在下面提供了4个带有预期警告的列表.

For concreteness, I have provided 4 lists with the expected warnings below.

在R中有可能吗?

A = list(x = c(1,1,1,1), y = c(2,4,3,3)) # Expect warning that says `y` is bad!

B = list(x = c(1,2,1,1), y = c(3,3,3,3)) # Expect warning that says `x` is bad!

C = list(x = c(1,2,1,1), y = c(3,2,3,3)) # Expect warning that says `x` and `y` are bad!

D = list(x = c(1,1,1,1), y = c(3,3,3,3)) # Expect no warning !

推荐答案

我们可以创建一个条件来检查元素中每个元素中 unique 元素的 length 列表

We could create a condition to check the length of unique elements in each of the elements in the list

f1 <- function(lst_obj) {
      v1 <- sapply(lst_obj, function(x) length(unique(x)))
      i1 <- names(which(v1 != 1))
      if(length(i1) == 1) {
          warning(paste(i1, " is bad!"))
       } else if(length(i1) > 1) {
           warning(paste(i1, collapse = ' and '), " are bad!")
       } 
    
}

f1(A)
#Warning message:
#In f1(A) : y is bad!

f1(B)
#Warning message:
#In f1(B) : x is bad!

f1(C)
#Warning message:
#In f1(C) : x and y are bad!
f1(D)

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