> ## Documentation Index
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# atoti.array.len()

### atoti.array.len(measure, /)

Return a measure equal to the number of elements of the passed array measure.

### Example

```pycon theme={"languages":{"custom":["/engine/python-sdk/0.9/languages/pycon.tmLanguage.json"]}}
>>> pnl_table = session.read_csv(
...     TEST_RESOURCES_PATH / "csv" / "pnl.csv",
...     array_separator=";",
...     keys={"Continent", "Country"},
...     table_name="PnL",
... )
>>> cube = session.create_cube(pnl_table)
>>> l, m = cube.levels, cube.measures
>>> m["Length"] = tt.array.len(m["PnL.SUM"])
>>> cube.query(m["PnL.SUM"], m["Length"])
                          PnL.SUM Length
0  doubleVector[10]{-20.163, ...}     10
```

* **Parameters:**
  **measure** (*VariableMeasureConvertible*)
* **Return type:**
  *MeasureDefinition*