We can customize DataTables through the options argument of DT::datatable(). Below is a brief explanation of the examples above:

1. the option pageLength = 25 changes the default number of rows to display from 10 to 25;

2. the option lengthMenu = list(c(5, 15, -1), c('5', '15', 'All')) sets the length menu items (in the top left corner); it can be either a numeric vector (e.g. c(5, 10, 30, 100)), or a list of length 2 -- in the latter case, the first element is the length options, and the second element contains their labels to be shown in the menu;

3. paging = FALSE disables pagination, i.e. all records in the data are shown at once; alternatively, you can set pageLength = -1;

4. searching = FALSE disables searching, and no searching boxes will be shown;

5. any character strings wrapped in JS() will be treated as literal JavaScript code, and evaluated using eval() in JavaScript, so we can pass, for example, JS functions to DataTables;