Convert a List to a Character Matrix

This function converts a given list of atomic vectors to a character matrix.

Usage

stri_list2matrix(
  x,
  byrow = FALSE,
  fill = NA_character_,
  n_min = 0,
  by_row = byrow
)

Arguments

x

a list of atomic vectors

byrow

a single logical value; should the resulting matrix be transposed?

fill

a single string, see Details

n_min

a single integer value; minimal number of rows (byrow==FALSE) or columns (otherwise) in the resulting matrix

by_row

alias of byrow

Value

Returns a character matrix.

Details

This function is similar to the built-in simplify2array function. However, it always returns a character matrix, even if each element in x is of length 1 or if elements in x are not of the same lengths. Moreover, the elements in x are always coerced to character vectors.

If byrow is FALSE, then a matrix with length(x) columns is returned. The number of rows is the length of the longest vector in x, but no less than n_min. Basically, we have result[i,j] == x[[j]][i] if i <= length(x[[j]]) and result[i,j] == fill otherwise, see Examples.

If byrow is TRUE, then the resulting matrix is a transposition of the above-described one.

This function may be useful, e.g., in connection with stri_split and stri_extract_all.

See also

The official online manual of stringi at https://stringi.gagolewski.com/

Gagolewski M., stringi: Fast and portable character string processing in R, Journal of Statistical Software 103(2), 2022, 1-59, doi:10.18637/jss.v103.i02

Other utils: stri_na2empty(), stri_remove_empty(), stri_replace_na()

Author

Marek Gagolewski and other contributors

Examples

simplify2array(list(c('a', 'b'), c('c', 'd'), c('e', 'f')))
#>      [,1] [,2] [,3]
#> [1,] "a"  "c"  "e" 
#> [2,] "b"  "d"  "f" 
stri_list2matrix(list(c('a', 'b'), c('c', 'd'), c('e', 'f')))
#>      [,1] [,2] [,3]
#> [1,] "a"  "c"  "e" 
#> [2,] "b"  "d"  "f" 
stri_list2matrix(list(c('a', 'b'), c('c', 'd'), c('e', 'f')), byrow=TRUE)
#>      [,1] [,2]
#> [1,] "a"  "b" 
#> [2,] "c"  "d" 
#> [3,] "e"  "f" 

simplify2array(list('a', c('b', 'c')))
#> [[1]]
#> [1] "a"
#> 
#> [[2]]
#> [1] "b" "c"
#> 
stri_list2matrix(list('a', c('b', 'c')))
#>      [,1] [,2]
#> [1,] "a"  "b" 
#> [2,] NA   "c" 
stri_list2matrix(list('a', c('b', 'c')), fill='')
#>      [,1] [,2]
#> [1,] "a"  "b" 
#> [2,] ""   "c" 
stri_list2matrix(list('a', c('b', 'c')), fill='', n_min=5)
#>      [,1] [,2]
#> [1,] "a"  "b" 
#> [2,] ""   "c" 
#> [3,] ""   ""  
#> [4,] ""   ""  
#> [5,] ""   ""