r - 按特定顺序从矩阵中选择行

Question

我有一个 2192*23 阶矩阵，我想选择行号“3rd”、“4th”、“10th”、“11th”、“17th”、“18th”、“24th”、“25th” "等等

[3,4,10,11,17,18,24,25,31,32,38,39,45,46,...]

按照上述顺序继续到最后一行。我将如何在 R 中执行此操作？

Answer 1

a1 <- c(3, 4)
d <- 7
n <- 10

S1 <- a1[1] + d * (seq(n) - 1)
S2 <- a1[2] + d * (seq(n) - 1)
sort(c(S1, S2))
#>  [1]  3  4 10 11 17 18 24 25 31 32 38 39 45 46 52 53 59 60 66 67

library(magrittr)
sapply(a1, function(x) (x + d * (seq(n) - 1))) %>% 
  matrix(ncol = 1) %>% 
  sort
#>  [1]  3  4 10 11 17 18 24 25 31 32 38 39 45 46 52 53 59 60 66 67

^{由 reprex package 创建于 2022-01-18 (v2.0.1)}