Data Validation¶
Data validation flags cells that break a rule you define, painting each failing cell red so problems stand out at a glance. Open it via Columns -> Data validation....
Rules¶
The dialog holds a list of rules. Each rule has a column (a specific
column, or (any column) to check every cell) and a kind:
| Kind | A cell fails when... |
|---|---|
| Not empty | the cell is empty or blank. |
| In range | the value is not a number, or falls outside the optional min / max (leave a bound blank to leave that side open). |
| Matches pattern | the text does not match the regular expression. |
| Unique | the value is duplicated elsewhere in the column. |
| Max length | the text is longer than the given number of characters. |
The footer shows a live count of how many cells currently fail.
How it behaves¶
Rules apply live: failing cells are highlighted the moment you add or edit a rule, and the highlight updates as you change cell values. The validation highlight is per tab and session-only - it is not saved with the file and does not change the data, only how it is shown. A manual colour mark or a conditional-formatting colour takes priority over the red validation highlight.
Add rule appends a new rule, the X button removes one, and Clear all removes them all.
See also¶
- Conditional Formatting colours cells by a rule for emphasis, rather than flagging errors.
- Search & Filter can narrow the table to the rows you want to inspect before validating.