5 examples of 'combine two dataframes pandas' in Python

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def _concat(df, type):
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    if df is None:
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        df = pd.DataFrame(_object_blocks[type])
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    else:
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        _df = pd.DataFrame(_object_blocks[type])
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        df = pd.concat([df, _df], sort=True)
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    return df

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def append_data(df1, df2):
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    '''
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    Append df2 to df1
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    '''
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    df = pd.concat((df1, df2))
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    return df.groupby(df.index).first()

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def _merge_dataframes(self, dataset_readers_list):
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    final_df = None
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    all_dfs = []
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    keys = []
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    for dataset, readers in dataset_readers_list:
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        dataset_df = readers[0]
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        for df in readers[1:]:
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            if df is None:
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                continue
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            dataset_df = dataset_df.add(df, fill_value=0.)
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        all_dfs.append(dataset_df)
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        keys.append(dataset)
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    final_df = pd.concat(all_dfs, keys=keys, names=['dataset'], sort=True)
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    return final_df.reset_index()

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def combine(self, obsra, inplace=True):
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    """
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    concatenates a new obsra onto the end of the current one.
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    """
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    newobsra = pd.concat([self.obsra, obsra])
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    if inplace: self.obsra = newobsra
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    return newobsra

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def feature_combiner(df):
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    combs = list(combinations(df.columns, 2))
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    for i, j in combs:
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        column_name = "%s-%s" % (i, j)
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        df[column_name] = df[i] - df[j]
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    return df