相关疑难解决方法(0)

请考虑以下示例:

require(tibble)
require(dplyr)

set.seed(42)

tbl <- data_frame(id = letters[1:10], val = c(runif(5), NA, runif(4)))

tbl

# A tibble: 10 × 2
      id          val
   <chr>        <dbl>
1      a 0.9148060435
2      b 0.9370754133
3      c 0.2861395348
4      d 0.8304476261
5      e 0.6417455189
6      f           NA
7      g 0.5190959491
8      h 0.7365883146
9      i 0.1346665972
10     j 0.6569922904

我想排序tibble的val,把NA第一个:

tbl %>%
  arrange(val)

# A tibble: 10 × 2
      id          val
   <chr>        <dbl>
1      i 0.1346665972
2      c …