R - 如何 intersect() 并包含重复项？

Question

我有以下要交叉的字符字段。这些应该是相等的。

> char.y[[892]]
 [1] "E" "d" "w" "a" "r" "d" "s" " " "L" "i" "f" "e" "s" "c" "i" "e" "n" "c" "e" "s"
> char.x[[892]]
 [1] "E" "d" "w" "a" "r" "d" "s" " " "L" "i" "f" "e" "s" "c" "i" "e" "n" "c" "e" "s"
> intersect(char.x[[892]], char.y[[892]])
 [1] "E" "d" "w" "a" "r" "s" " " "L" "i" "f" "e" "c" "n"
>

预期结果：

"E" "d" "w" "a" "r" "d" "s" " " "L" "i" "f" "e" "s" "c" "i" "e" "n" "c" "e"

Answer 1

使用 intersect 将 return 通用元素，但不会重复它们。例如，s 出现了 3 次，但只会出现一次。

如果您想查看相同的布局，例如删除非交叉值，您可以使用以下内容：

a <- c("E", "d", "w", "a", "r", "d", "s", " ", "L", "i", "f", "e", "s", "c", "i", "e", "n", "c", "e", "s")
b <- c("E", "d", "w", "a", "r", "d", "s", " ", "L", "i", "f", "e", "s", "c", "i", "e", "n", "c", "e", "s")
a[a %in% intersect(a, b)]
#  [1] "E" "d" "w" "a" "r" "d" "s" " " "L" "i" "f" "e" "s" "c" "i" "e" "n" "c" "e" "s"

Answer 2

这完全取决于您比较的向量（以及顺序），但这是否足够？

b <- a <- c('E', 'd', 'w', 'a', 'r', 'd', 's', '', 'L', 'i', 'f', 'e', 's', 'c', 'i', 'e', 'n', 'c', 'e')
c <- letters[sample(1:26,100, rep=T)]

a[is.element(a,b)]
#  [1] "E" "d" "w" "a" "r" "d" "s" ""  "L" "i" "f" "e" "s" "c" "i" "e" "n" "c" "e"

a[is.element(a,c)]
# [1] "d" "w" "a" "r" "d" "s" "i" "f" "e" "s" "c" "i" "e" "n" "c" "e"

Answer 3

我遇到了完全相同的问题，但没有找到解决方案，所以我创建了自己的小函数 "intersectdup":

intersectdup <- function(vektor1, vektor2) {
    result <- c()
    for (i in 1:length(vektor2)) {
        if (is.element(vektor2[i], vektor1)){
            result <- c(result, vektor2[i])
            foundAt <- match(vektor2[i], vektor1)
            vektor1 <- c(vektor1[1:foundAt-1], vektor1[foundAt+1:length(vektor1)])
        }
    }
    return(result)
}

Answer 4

以 Clemens 为例，这是 c-based 结构中的一个简单函数：

intersectMe = function(x, y, duplicates=TRUE)
    {
    xyi = intersect(x,y);
    if(!duplicates) { return (xyi); }
    
    res = c();  
    for(xy in xyi)
        {
        y.xy = which(y == xy);  ny.xy = length(y.xy);
        x.xy = which(x == xy);  nx.xy = length(x.xy);
        
        min.xy = min(ny.xy, nx.xy);
        
        res = c(res, rep(xy, min.xy) );
        }
    
    res;    
    }

Answer 5

vecsets 库也有帮助（使用 Eric 创建的示例）

vecsets::vintersect(a, b)

 [1] "E" "d" "d" "w" "a" "r" "s" "s" "s" " " "L" "i" "i" "f" "e" "e" "e" "c" "c" "n"

R - 如何 intersect() 并包含重复项？

R - How to intersect() and include duplicates?

r

character

intersect