In "corrr" package, how to add asterisks for statistical significance

Question

I have a correlation matrix that includes bivariate correlations among 14 variables. How can I append asterisks to denote statistical significance? I am using the following code:

pretty.matrix<-a %>%  
  correlate() %>%  
  shave() %>% 
  fashion() %>% 
  print()

Answer 1

You could use a function that prints the statistical significance. Using the colpair_map it will be easy to make a pretty matrix. I used the mtcars dataset as example. You can use the code below:

library(corrr)
  library(tidyverse)
  
  # Function
  calc_p_value <- function(vec_a, vec_b, sig_level){
    test_res <- cor.test(vec_a, vec_b)
    sig <- if_else(test_res$p.value < sig_level, "*", "")
    paste0(round(cor.test(vec_a, vec_b)$estimate, 2), sig)
  }
  
  # Matrix with p = 0.05
  colpair_map(mtcars, calc_p_value, 0.05) %>%
    shave()

Output looks like this:

# A tibble: 11 × 12
   term  mpg    cyl    disp   hp     drat   wt     qsec   vs     am    gear  carb 
   <chr> <chr>  <chr>  <chr>  <chr>  <chr>  <chr>  <chr>  <chr>  <chr> <chr> <chr>
 1 mpg   NA     NA     NA     NA     NA     NA     NA     NA     NA    NA    NA   
 2 cyl   -0.85* NA     NA     NA     NA     NA     NA     NA     NA    NA    NA   
 3 disp  -0.85* 0.9*   NA     NA     NA     NA     NA     NA     NA    NA    NA   
 4 hp    -0.78* 0.83*  0.79*  NA     NA     NA     NA     NA     NA    NA    NA   
 5 drat  0.68*  -0.7*  -0.71* -0.45* NA     NA     NA     NA     NA    NA    NA   
 6 wt    -0.87* 0.78*  0.89*  0.66*  -0.71* NA     NA     NA     NA    NA    NA   
 7 qsec  0.42*  -0.59* -0.43* -0.71* 0.09   -0.17  NA     NA     NA    NA    NA   
 8 vs    0.66*  -0.81* -0.71* -0.72* 0.44*  -0.55* 0.74*  NA     NA    NA    NA   
 9 am    0.6*   -0.52* -0.59* -0.24  0.71*  -0.69* -0.23  0.17   NA    NA    NA   
10 gear  0.48*  -0.49* -0.56* -0.13  0.7*   -0.58* -0.21  0.21   0.79* NA    NA   
11 carb  -0.55* 0.53*  0.39*  0.75*  -0.09  0.43*  -0.66* -0.57* 0.06  0.27  NA