In R purrrr why group_split change the row order alphabetically?-CodePudding

This is my code:

df <- mtcars %>% rownames_to_column()

When I use group_split(rowname)the order is change alphabetically, why?

How can I maintain the original order?

df %>% group_split(rowname)

CodePudding user response：

That's the default behaviour of group_by which is what group_split uses behind the scenes: arrange your variable before grouping. In this case, because it's a string, it sorts alphabetically. To keep your original order you can turn the variable into a factor:

df = df %>% mutate(rowname = factor(rowname, levels = unique(rowname)))

Output:

>[32]>
[[1]]
# A tibble: 1 × 12
  rowname     mpg   cyl  disp    hp  drat    wt  qsec    vs    am  gear  carb
  <fct>     <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
1 Mazda RX4    21     6   160   110   3.9  2.62  16.5     0     1     4     4

[[2]]
# A tibble: 1 × 12
  rowname         mpg   cyl  disp    hp  drat    wt  qsec    vs    am  gear  carb
  <fct>         <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
1 Mazda RX4 Wag    21     6   160   110   3.9  2.88  17.0     0     1     4     4
.
.
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[[32]]

# A tibble: 1 × 12
  rowname      mpg   cyl  disp    hp  drat    wt  qsec    vs    am  gear  carb
  <fct>      <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
1 Volvo 142E  21.4     4   121   109  4.11  2.78  18.6     1     1     4     2