R corrr stretch 將相關數據幀拉伸為長格式。

stretch(x, na.rm = FALSE, remove.dups = FALSE)

x <- correlate(mtcars)
#> Correlation computed with
#> • Method: 'pearson'
#> • Missing treated using: 'pairwise.complete.obs'
stretch(x) # Convert all to long format
#> # A tibble: 121 × 3
#>    x     y          r
#>    <chr> <chr>  <dbl>
#>  1 mpg   mpg   NA    
#>  2 mpg   cyl   -0.852
#>  3 mpg   disp  -0.848
#>  4 mpg   hp    -0.776
#>  5 mpg   drat   0.681
#>  6 mpg   wt    -0.868
#>  7 mpg   qsec   0.419
#>  8 mpg   vs     0.664
#>  9 mpg   am     0.600
#> 10 mpg   gear   0.480
#> # … with 111 more rows
#> # ℹ Use `print(n = ...)` to see more rows
stretch(x, na.rm = TRUE) # omit NAs (diagonal in this case)
#> # A tibble: 110 × 3
#>    x     y          r
#>    <chr> <chr>  <dbl>
#>  1 mpg   cyl   -0.852
#>  2 mpg   disp  -0.848
#>  3 mpg   hp    -0.776
#>  4 mpg   drat   0.681
#>  5 mpg   wt    -0.868
#>  6 mpg   qsec   0.419
#>  7 mpg   vs     0.664
#>  8 mpg   am     0.600
#>  9 mpg   gear   0.480
#> 10 mpg   carb  -0.551
#> # … with 100 more rows
#> # ℹ Use `print(n = ...)` to see more rows

x <- shave(x) # use shave to set upper triangle to NA and then...
stretch(x, na.rm = TRUE) # omit all NAs, therefore keeping each
#> # A tibble: 55 × 3
#>    x     y          r
#>    <chr> <chr>  <dbl>
#>  1 mpg   cyl   -0.852
#>  2 mpg   disp  -0.848
#>  3 mpg   hp    -0.776
#>  4 mpg   drat   0.681
#>  5 mpg   wt    -0.868
#>  6 mpg   qsec   0.419
#>  7 mpg   vs     0.664
#>  8 mpg   am     0.600
#>  9 mpg   gear   0.480
#> 10 mpg   carb  -0.551
#> # … with 45 more rows
#> # ℹ Use `print(n = ...)` to see more rows
# correlation only once.