Modify Whole Table or Plot - Show Only Top K Rows (e.g., Top 5 Rows)

This rule allows you to select the number of rows to show on a table or chart. The user is able to specify the number of rows (i.e., k). If used after first applying Sorting and Reordering - Sort Rows (Automatically Updates when Data Changes), it allows you to show, for example, the top 3 brands automatically. See also Modifying the Whole Table or Plot - Showing Only the Top k and Specified Rows.

Example

How to apply this rule

For the first time in a project

Select the table(s)/chart(s) that you wish to apply the rule to.
Start typing the name of the Rule into the Search features and data box in the top right of the Q window.
Click on the Rule when it appears in the QScripts and Rules section of the search results.

OR

Select Automate > Browse Online Library.
Choose this rule from the list.

Additional applications of the rule

Select a table or chart that has the rule and any table(s)/chart(s) that you wish to apply the rule to.
Click on the Rules tab (bottom-left of the table/chart).
Select the rule that you wish to apply.
Click on the Apply drop-down and choose your desired option.
Check New items to have it automatically applied to new items that you create. Use Edit > Project Options > Save as Template to create a new project template that automatically uses this rule.

Removing the rule

Select the table(s)/chart(s) that you wish to remove the rule from.
Press the Rules tab (bottom-right corner).
Press Apply next to the rule you wish to remove and choose the appropriate option.

How to modify the rule

Click on the Rules tab (bottom-left of the table/chart).
Select the rule that you wish to modify.
Click Edit Rule and make the desired changes. Alternatively, you can use the JavaScript below to make your own rule (see Customizing Rules).

JavaScript

You can find a detailed discussion of this code at Creating a Custom Rule.

includeWeb("Table JavaScript Utility Functions");
 
// creating the form
form.setHeading('Show Only the Top Rows');
let description = form.newLabel("Show only the top rows in the table.")
description.lineBreakAfter = true;
let number_label = form.newLabel('Number of rows:'); //creating the phrase 'Number of rows:' 
let numeric_up_down = form.newNumericUpDown('threshold'); //creating a control where a user can enter a number.
numeric_up_down.setDefault(5);// specifying the default number of rows to be shown
numeric_up_down.setIncrement(1); // specifying that the user must enter whole numbers.
numeric_up_down.setMinimum(1); // preventing the user from having tables with less than 1 row
form.setInputControls([description, number_label, numeric_up_down]); // telling Q to create the form
// Extracting the number of rows provided by the user and assigning it to a variable.
let maximum_number_rows = numeric_up_down.getValue();
 
// Deleting the rows.
while(table.numberRows > maximum_number_rows)
    deleteRowComplete(table.numberRows - 1); 
// creating the form title
form.setSummary('Show the top ' + maximum_number_rows + ' rows');
 
// Returns true if Statistics - Right are available for this table.
// This function needs to be kept in the main body of the rule to ensure
// that right_table is included properly before the rule code is
// executed.
function rightTableExists() {
    let exists = true;
    try { 
        right_table.statistics;
    } catch (e) {
        exists = false;
    }
    return exists;
}