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  * polars.LazyF... 

#  polars.LazyFrame.shift  #

LazyFrame.  shift  (

     _ n  :  [ int  ](https://docs.python.org/3/library/functions.html#int "\(in Python v3.12\)") |  IntoExprColumn  =  1  _ , 
     _ *  _ , 
     _ fill_value  :  IntoExpr  |  [ None  ](https://docs.python.org/3/library/constants.html#None "\(in Python v3.12\)") =  None  _ , 
)  →  Self  [ [source]  ](https://github.com/pola-rs/polars/blob/main/py-
polars/polars/lazyframe/frame.py#L4395-L4472) #

    

Shift values by the given number of indices.

Parameters  :

    

**n**

    

Number of indices to shift forward. If a negative value is passed, values are
shifted in the opposite direction instead.

**fill_value**

    

Fill the resulting null values with this value. Accepts expression input. Non-
expression inputs are parsed as literals.

Notes

This method is similar to the ` LAG  ` operation in SQL when the value for ` n
` is positive. With a negative value for ` n  ` , it is similar to ` LEAD  ` .

Examples

By default, values are shifted forward by one index.

    
    
    >>> lf = pl.LazyFrame(
    ...     {
    ...         "a": [1, 2, 3, 4],
    ...         "b": [5, 6, 7, 8],
    ...     }
    ... )
    >>> lf.shift().co