# xarray.DataArray.var

#### DataArray.var(dim=None, , skipna=None, ddof=0, keep_attrs=None, \*\*kwargs)[[source]](https://github.com/pydata/xarray/blob/main/xarray/core/_aggregations.py#L3341-L3434)

Reduce this DataArray’s data by applying `var` (i.e., variance) along some dimension(s).

* **Parameters:**
  * **dim** ([`str`](xarray.DataArray.str.html.md#xarray.DataArray.str), `Iterable` of `Hashable`, `"..."` or [`None`](https://docs.python.org/3/builtins/constants.html#None), *default*: [`None`](https://docs.python.org/3/builtins/constants.html#None)) – Name of dimension[s] along which to apply `var`. For e.g. `dim="x"`
    or `dim=["x", "y"]`. If “…” or None, will reduce over all dimensions.
  * **skipna** ([`bool`](https://docs.python.org/3/builtins/functions.html#bool) or [`None`](https://docs.python.org/3/builtins/constants.html#None), *optional*) – If True, skip missing values (as marked by NaN). By default, only
    skips missing values for float dtypes; other dtypes either do not
    have a sentinel missing value (int) or `skipna=True` has not been
    implemented (object, datetime64 or timedelta64).
  * **ddof** ([`int`](https://docs.python.org/3/builtins/functions.html#int), *default*: `0`) – “Delta Degrees of Freedom”: the divisor used in the calculation is `N - ddof`,
    where `N` represents the number of elements.
  * **keep_attrs** ([`bool`](https://docs.python.org/3/builtins/functions.html#bool) or [`None`](https://docs.python.org/3/builtins/constants.html#None), *optional*) – If True, `attrs` will be copied from the original
    object to the new one.  If False, the new object will be
    returned without attributes.
  * **\*\*kwargs** (`Any`) – Additional keyword arguments passed on to the appropriate array
    function for calculating `var` on this object’s data.
    These could include dask-specific kwargs like `split_every`.
* **Returns:**
  **reduced** ([`DataArray`](xarray.DataArray.html.md#xarray.DataArray)) – New DataArray with `var` applied to its data and the
  indicated dimension(s) removed

#### SEE ALSO
[`numpy.var`](https://numpy.org/doc/stable/reference/generated/numpy.var.html#numpy.var), [`dask.array.var`](https://docs.dask.org/en/latest/generated/dask.array.var.html#dask.array.var), [`Dataset.var`](xarray.Dataset.var.html.md#xarray.Dataset.var)

[Aggregation](../user-guide/computation.html.md#agg)
: User guide on reduction or aggregation operations.

### Notes

Non-numeric variables will be removed prior to reducing. datetime64 and timedelta64 dtypes are treated as numeric for aggregation operations.

### Examples

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```pycon
>>> da = xr.DataArray(
...     np.array([1, 2, 3, 0, 2, np.nan]),
...     dims="time",
...     coords=dict(
...         time=("time", pd.date_range("2001-01-01", freq="ME", periods=6)),
...         labels=("time", np.array(["a", "b", "c", "c", "b", "a"])),
...     ),
... )
>>> da
<xarray.DataArray (time: 6)> Size: 48B
array([ 1.,  2.,  3.,  0.,  2., nan])
Coordinates:
  * time     (time) datetime64[us] 48B 2001-01-31 2001-02-28 ... 2001-06-30
    labels   (time) <U1 24B 'a' 'b' 'c' 'c' 'b' 'a'
```

```pycon
>>> da.var()
<xarray.DataArray ()> Size: 8B
array(1.04)
```

Use `skipna` to control whether NaNs are ignored.

```pycon
>>> da.var(skipna=False)
<xarray.DataArray ()> Size: 8B
array(nan)
```

Specify `ddof=1` for an unbiased estimate.

```pycon
>>> da.var(skipna=True, ddof=1)
<xarray.DataArray ()> Size: 8B
array(1.3)
```

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