在R中：如何测试列表或向量中矩阵元素的隶属关系

Question

说我有一个矩阵m

      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
 [1,]    0    1    3    5    9   11   15   17   21    27
 [2,]    0    0    2    4    8   10   14   16   20    26
 [3,]    0    0    0    2    6    8   12   14   18    24
 [4,]    0    0    0    0    4    6   10   12   16    22
 [5,]    0    0    0    0    0    2    6    8   12    18
 [6,]    0    0    0    0    0    0    4    6   10    16
 [7,]    0    0    0    0    0    0    0    2    6    12
 [8,]    0    0    0    0    0    0    0    0    4    10
 [9,]    0    0    0    0    0    0    0    0    0     6
[10,]    0    0    0    0    0    0    0    0    0     0

dput是：

structure(c(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 3, 2, 0, 0, 0, 0, 0, 0, 0, 0, 5, 4, 2, 0, 0, 0, 0, 0, 
0, 0, 9, 8, 6, 4, 0, 0, 0, 0, 0, 0, 11, 10, 8, 6, 2, 0, 0, 0, 
0, 0, 15, 14, 12, 10, 6, 4, 0, 0, 0, 0, 17, 16, 14, 12, 8, 6, 
2, 0, 0, 0, 21, 20, 18, 16, 12, 10, 6, 4, 0, 0, 27, 26, 24, 22, 
18, 16, 12, 10, 6, 0), .Dim = c(10L, 10L))

说我有向量p

 [1]  2  3  5  7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71

dput是：

c(2L, 3L, 5L, 7L, 11L, 13L, 17L, 19L, 23L, 29L)

我想将矩阵中不在p中的所有值设置为零

我如何优雅地做到这一点？

Answer 1

尝试

m1[!m1 %in% p] <- 0

或者像您在上一个问题中一样，我们可以将逻辑索引与'm1'相乘，以便'TRUE / FALSE gets coerced to binary ( 1 / 0`），然后将'0 / FALSE'值与'm1'的相应元素相乘得到'结果为0'。

m1 <- (m1 %in% p)*m1

数据

m1 <- structure(c(0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 1L, 0L, 0L, 
0L, 0L, 0L, 0L, 0L, 0L, 0L, 3L, 2L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 
0L, 5L, 4L, 2L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 9L, 8L, 6L, 4L, 0L, 
0L, 0L, 0L, 0L, 0L, 11L, 10L, 8L, 6L, 2L, 0L, 0L, 0L, 0L, 0L, 
15L, 14L, 12L, 10L, 6L, 4L, 0L, 0L, 0L, 0L, 17L, 16L, 14L, 12L, 
8L, 6L, 2L, 0L, 0L, 0L, 21L, 20L, 18L, 16L, 12L, 10L, 6L, 4L, 
0L, 0L, 27L, 26L, 24L, 22L, 18L, 16L, 12L, 10L, 6L, 0L), .Dim = c(10L, 
10L))

p <- c(2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47,
          53, 59, 61, 67, 71)