olars.exceptions.DuplicateError.html)
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  * [ __ ](../../../index.html)
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  * __
  * [ Aggregation ](../aggregation.html)
  * polars.LazyF... 

#  polars.LazyFrame.null_count  #

LazyFrame.  null_count  (  )  →  Self  [ [source]  ](https://github.com/pola-
rs/polars/blob/main/py-polars/polars/lazyframe/frame.py#L5267-L5290) #

    

Aggregate the columns in the LazyFrame as the sum of their null value count.

Examples

    
    
    >>> lf = pl.LazyFrame(
    ...     {
    ...         "foo": [1, None, 3],
    ...         "bar": [6, 7, None],
    ...         "ham": ["a", "b", "c"],
    ...     }
    ... )
    >>> lf.null_count().collect()
    shape: (1, 3)
    ┌─────┬─────┬─────┐
    │ foo ┆ bar ┆ ham │
    │ --- ┆ --- ┆ --- │
    │ u32 ┆ u32 ┆ u32 │
    ╞═════╪═════╪═════╡
    │ 1   ┆ 1   ┆ 0   │
    └─────┴─────┴─────┘
    

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  * ` LazyFrame.null_count()  `

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