# xarray.Dataset.drop_duplicates

#### Dataset.drop_duplicates(dim, , keep='first')[[source]](https://github.com/pydata/xarray/blob/main/xarray/core/dataset.py#L10133-L10220)

Return a new Dataset with duplicate dimension values removed.

* **Parameters:**
  * **dim** (`dimension label` or `labels`) – Pass … to drop duplicates along all dimensions.
  * **keep** (`{"first", "last", False}`, *default*: `"first"`) – Determines which duplicates (if any) to keep.
    - `"first"` : Drop duplicates except for the first occurrence.
    - `"last"` : Drop duplicates except for the last occurrence.
    - False : Drop all duplicates.
* **Returns:**
  [`Dataset`](xarray.Dataset.html.md#xarray.Dataset)

#### SEE ALSO
[`DataArray.drop_duplicates`](xarray.DataArray.drop_duplicates.html.md#xarray.DataArray.drop_duplicates)

### Examples

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```pycon
>>> ds = xr.Dataset(
...     {"temperature": ("time", [10, 12, 14, 16])},
...     coords={"time": [0, 1, 1, 2]},
... )
```

```pycon
>>> ds
<xarray.Dataset> Size: 64B
Dimensions:      (time: 4)
Coordinates:
  * time         (time) int64 32B 0 1 1 2
Data variables:
    temperature  (time) int64 32B 10 12 14 16
```

By default, the first value for each coordinate label is kept:

```pycon
>>> ds.drop_duplicates("time")
<xarray.Dataset> Size: 48B
Dimensions:      (time: 3)
Coordinates:
  * time         (time) int64 24B 0 1 2
Data variables:
    temperature  (time) int64 24B 10 12 16
```

Use `keep="last"` to retain the last value for a repeated label:

```pycon
>>> ds.drop_duplicates("time", keep="last")
<xarray.Dataset> Size: 48B
Dimensions:      (time: 3)
Coordinates:
  * time         (time) int64 24B 0 1 2
Data variables:
    temperature  (time) int64 24B 10 14 16
```

Use `keep=False` to discard every occurrence of duplicated labels:

```pycon
>>> ds.drop_duplicates("time", keep=False)
<xarray.Dataset> Size: 32B
Dimensions:      (time: 2)
Coordinates:
  * time         (time) int64 16B 0 2
Data variables:
    temperature  (time) int64 16B 10 16
```

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