Count Values in Arrow Files Online
Group and count rows by any column in Arrow files directly in your browser. Sort by frequency or value to find the most common entries — no upload required.
How to count Values in Arrow files
- Drop your file onto the upload area. The row count is shown and the first column is pre-selected.
- Choose a column in the Group by column list.
- Pick a sort order: Count (high → low), Count (low → high) or Value (A → Z).
- Click Count. The result has two columns, value and count, and the heading shows how many distinct values were found.
- Click Download to save the counts in the same format you uploaded, with _countby added to the file name.
Your file is processed locally in your browser and is never uploaded. The free limit is 50 MB per file; larger files work if your device has the memory for them.
Worked example
A city bike-share scheme wants to know which docking stations trips start from most often. A few trips from a faulty dock have no start station recorded.
Input (Arrow)
Arrow IPC file (binary, columnar) — shown as a table with its schema
| trip_id | start_station | duration_min | rider_type |
|---|---|---|---|
| 5001 | Quay St | 12 | member |
| 5002 | Park Rd | 25 | casual |
| 5003 | Quay St | 8 | member |
| 5004 | NULL | 17 | casual |
| 5005 | Quay St | 31 | casual |
| 5006 | Park Rd | 9 | member |
Schema: trip_id BIGINT, start_station VARCHAR, duration_min BIGINT, rider_type VARCHAR
Settings
- Group by column: start_station
- Sort by: Count (high → low)
Result
| value | count |
|---|---|
| Quay St | 3 |
| Park Rd | 2 |
| NULL | 1 |
Six trips collapse to three groups. Quay St has three trips, Park Rd two, and the trip with no station forms its own group with a null value. Missing values are counted, not dropped, so the counts always add up to the total row count. The output columns are always named value and count, whatever the source column was called.
Frequently Asked Questions
Can I count by more than one column?
No. The tool groups by one column. For combinations of columns, use the Aggregate tool or the SQL Query tool with GROUP BY on several columns.
How are ties ordered when sorting by count?
Values with the same count have no fixed order between them. Choose Value (A → Z) if you need a stable, alphabetical order.
Does the on-screen table show every value?
The on-screen table shows the first 500 groups. The heading still gives the full number of distinct values, and the downloaded file contains every group.
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