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  • set_index

    Signature:
    df.set_index(
        ['keys', 'drop=True', 'append=False', 'inplace=False', 'verify_integrity=False'],
    )
    Docstring:
    Set the DataFrame index (row labels) using one or more existing
    columns. By default yields a new object.
    
    Parameters
    ----------
    keys : column label or list of column labels / arrays
    drop : boolean, default True
        Delete columns to be used as the new index
    append : boolean, default False
        Whether to append columns to existing index
    inplace : boolean, default False
        Modify the DataFrame in place (do not create a new object)
    verify_integrity : boolean, default False
        Check the new index for duplicates. Otherwise defer the check until
        necessary. Setting to False will improve the performance of this
        method
    
    Examples
    --------
    >>> df = pd.DataFrame({'month': [1, 4, 7, 10],
    ...                    'year': [2012, 2014, 2013, 2014],
    ...                    'sale':[55, 40, 84, 31]})
       month  sale  year
    0  1      55    2012
    1  4      40    2014
    2  7      84    2013
    3  10     31    2014
    
    Set the index to become the 'month' column:
    
    >>> df.set_index('month')
           sale  year
    month
    1      55    2012
    4      40    2014
    7      84    2013
    10     31    2014
    
    Create a multi-index using columns 'year' and 'month':
    
    >>> df.set_index(['year', 'month'])
                sale
    year  month
    2012  1     55
    2014  4     40
    2013  7     84
    2014  10    31
    
    Create a multi-index using a set of values and a column:
    
    >>> df.set_index([[1, 2, 3, 4], 'year'])
             month  sale
       year
    1  2012  1      55
    2  2014  4      40
    3  2013  7      84
    4  2014  10     31
    
    Returns
    -------
    dataframe : DataFrame
    File:      c:userslenovoanaconda3libsite-packagespandascoreframe.py
    Type:      method
    

      

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  • 原文地址:https://www.cnblogs.com/wangtaobiu/p/12006448.html
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