How to check whether a pandas DataFrame is empty?

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别跟我提以往
别跟我提以往 2020-12-02 04:01

How to check whether a pandas DataFrame is empty? In my case I want to print some message in terminal if the DataFrame is empty.

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  •  陌清茗
    陌清茗 (楼主)
    2020-12-02 04:39

    I use the len function. It's much faster than empty. len(df.index) is even faster.

    import pandas as pd
    import numpy as np
    
    df = pd.DataFrame(np.random.randn(10000, 4), columns=list('ABCD'))
    
    def empty(df):
        return df.empty
    
    def lenz(df):
        return len(df) == 0
    
    def lenzi(df):
        return len(df.index) == 0
    
    '''
    %timeit empty(df)
    %timeit lenz(df)
    %timeit lenzi(df)
    
    10000 loops, best of 3: 13.9 µs per loop
    100000 loops, best of 3: 2.34 µs per loop
    1000000 loops, best of 3: 695 ns per loop
    
    len on index seems to be faster
    '''
    

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