有一个小标题包含数字 1 到 4。
library(tidyverse)
# reproducible data
sample_tbl <- structure(list(X1 = c(4L, 4L, 1L, 4L, 1L, 4L, 2L, 3L, 2L, 4L),
X2 = c(1L, 4L, 4L, 4L, 4L, 2L, 4L, 4L, 3L, 2L), X3 = c(4L,
3L, 3L, 3L, 2L, 2L, 1L, 1L, 4L, 2L), X4 = c(1L, 4L, 3L, 2L,
3L, 4L, 2L, 1L, 1L, 1L), X5 = c(1L, 3L, 3L, 1L, 2L, 2L, 3L,
3L, 4L, 1L), X6 = c(2L, 3L, 4L, 4L, 3L, 2L, 4L, 1L, …