Grouping data and descriptive statistics

How to set statistical aggregators for a single column

Aggregators provide summary statistics for grouped rows.

The following statistical aggregators are available:

The follow howtos will have examples of workflows involving grouping of data and statistical aggregation.

How to create a pivot table

This example uses the file sample.tsv.

1. Press ! on the independent variable to set it as a key column.
2. Press + on a second column to add an aggregate. This configures which column is to be composed in relation to others.
3. Optional: Set the type for the column being aggregated by pressing ~ (string), # (int), % (float), $ (currency), or @ (date).
4. Press Shift+W on the dependent categorical variable to pivot on it.

How to create a frequency chart

The following examples use the file sample.tsv.

How to make a simple histogram

Question How many of each Item were sold?

1. Move the cursor to the Item column.
2. Press Shift+F to open the Frequency table.

How to use the Frequency table to view the results of statistical aggregation

Question What was the monthly revenue?

1. On the OrderDate column, type ; followed by (\d+-\d+) to create a column with only the year and the month using regex capture groups.
2. Press - to hide the OrderDate column.
3. On the **OrderDate_re0** column, type ^ followed by OrderDate to rename it.
4. On the Total column, press $ to set its type to currency.
5. Type + followed by sum to add a statistical aggregator to Total.
6. On the OrderDate column type Shift+F to open the Frequency table.
7. On the OrderDate column, press [ to sort the table in chrononological order.
8. On the **sum_Total** column, type ^ followed by Revenue to rename the column.

How to calculate some descriptive statistics

1. Press Shift+I to open the Describe sheet.

How to filter for grouped or described rows

How to filter for grouped rows

1. Press Shift+F to open the Frequency table.
2. Press s or t on the groups you are interested in to select those entries in the source sheet.
3. Press q or Ctrl+^ to return to the source sheet.
4. Press " to open a duplicate sheet with selected rows.

or

1. Press Shift+F to open the Frequency table.
2. Press Enter on the grouping you are interested in to open a sheet of the source rows that are part of that group.

How to filter for described rows

1. Press Shift+I to open the Describe sheet.
2. Use zs to select rows on source sheet which are being described in the cells of interest.
3. Press q or Ctrl+^ to return to the source sheet.
4. Press " to open a duplicate sheet with selected rows.

or

1. Press Shift+I to open the Describe sheet.
2. Press zEnter open copy of source sheet with rows being described in the current cell of interest.

How to filter for the rows aggregated in a pivot table

Enter/zEnter can both be used in the Pivot table to open a sheet of the source rows which are aggregated in the current pivot row/cell.

How to combine cells in one for column for matching rows in another

This tutorial shows you how to go from this dataset:

to

in VisiData.

1. On the value column, type + followed by list to add to it a list aggregator.
2. Press Shift+F on the field column to open the Frequency table.
3. Type = followed by ';'.join(value_list) to add an expression column with the joined values.