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VisiData is an interactive CLI table explorer with vim key bindings. Here is a really great tutorial. These are notes to myself.

Source Table Recommendations

Gather data with more granularity than you think you need. You often need three tables:

  1. Logs: Include date, build (includes platform ID), product ID, params of log, total count, unique devices.
  2. Device Activity: Includes date, build, product ID, active time, active device count.
  3. Mappings from product ID to product name: (Maybe from platform ID or from product ID.)

Open VisiData and Set Data Types

$ vd logs.csv active_devices.csv id_name.csv

Set Column Types, Widths, Names, Importance

Key Meaning
_ Adjust widths of columns
@ Column type is date.
! Column is important. (Will be key for table merging.)
# Column is integer. (Set aggregator to sum.)
+ Set aggregator, usually to “sum”
; Extract regex to new column. Ex, (video|audio), (^..) or (^([STUVW]...|..))
^ rename the column. Might have to be “product_id” or “platform_id”
- Hide column
S Go to “Sheets” sheet, to select another sheet to format.
q Leave the sheet. (gq quit all sheets)
F Make a Frequency Table for the selected column. (gF for selected columns)
U Undo. R Redo.
d Delete row. (I only use this on Sheets sheet.)
, Select all rows that match this column's value
Open duplicate sheet with only selected rows

Case Study: Exported CSV from PG&E

PG&E CSVs come with 5 rows of metadata followed by Type, Date, Start Time, End Time, Usage, Units, Cost, Notes columns. Delete the five rows of metadata in a text editor, or use tail to remove them like so:

  tail +6 pge_electric_interval_data.csv | vd -f csv -

Then prepare your PG&E data like so:

Key Meaning
- Hide columns TYPE, END TIME, UNITS and NOTES
C Go to column mode and…
t Select the DATE and START TIME columns
& Make a new column that merges them
q, - Quit the Column mode, hide DATE and START TIME columns
O Go to options mode and…
e Set disp_date_fmt to %Y-%m-%d %H:%M
q Quit options mode.
@!, %, $ Set DATE_START_TIME to date format and important, USAGE to float, COST to currency
= Add a column, enter COST/USAGE, (Make it float with %)
^ Rename COST/USAGE to kWh cost
. or g. Select columns to graph them. Notice rate changes. Notice times of high use.
+, - Navigate with hjkl, zoom in and out (more)

Protip: Use column view to set multiple columns at once

Key Meaning
C Go to column view, each row is data for a column.
t Select rows, select all integer rows.
ge Go to “type” column, enter ge (global edit), type “int”
Go to “aggregators”, enter ge, type “sum”
q Leave that table.

For example, your “logs.csv” would end up looking like:

Your active_devices.csv would look like this:

Join Sheets

Use ! to set Key columns. Use F (or gF) to remove dupes of Keys by making a Frequency Table.

Key Meaning
The key columns to join have to match names. Check and rename with ^.
S Go to Sheets sheet
t (toggle) Select the sheets you want to join by key columns.
& (or g&) Join sheets. Type “inner” for an inner join.
gu Next time you're in Sheets, “global unselect” to unselect the sheets you selected.

Protip: Remove insignificant noisy rows

Key Meaning
z| Select rows matching Python expression. Type “blits > 10000”
Make a new sheet with selected rows

And the merge of the logs and active devices sheets would look like:

Do a similar thing to join the Joined Sheet with the product Name sheet.

Process Data

In your final Joined sheet, add rows that are calculations of other rows.

Key Meaning
HL (JK for rows) Move columns
- Remove columns
Maybe use C to assure desired columns are ints and aggregators are “sum”
! Toggle key columns.
gF global Frequency Table so key columns are unique.
= Add column. Enter count_sum * 100 / active_devices_sum
% Set new column as float.
_ Resize columns
] Sort by column
. (g. for multiple columns) Make a graph based on Key column.

Now you should have some basic info to keep exploring. When you want to save what you've done:

Key Meaning
Ctrl+s Save sheet
Ctrl+d Save command log (cmdlog). Use extension “.vd”. You can replay what you've done later!

The commandlog is a CSV file too. The first lines are the open file commands. So to replay, you only have to specify the command log like so:

$ vd --play=my_cmdlog.vd --replay-wait=0.5
vd.1628281188.txt.gz · Last modified: 2021/08/06 13:19 by dblume