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导入模块
>>> import numpy as np
>>> import pandas as pd
>>> with open("../stack.py", "rt", encoding="utf8") as fp: exec(fp.read())
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测试stack参数
>>> df_single_level_cols = pd.DataFrame([[0, 1], [2, 3]], index=['cat', 'dog'], columns=['weight', 'height'])
>>> print(df_single_level_cols)
>>> res = stack(df_single_level_cols)
>>> print(res)
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测试unstack参数
>>> index = pd.MultiIndex.from_tuples([('one', 'a'), ('one', 'b'), ('two', 'a'), ('two', 'b')])
>>> s = pd.Series(np.arange(1.0, 5.0), index=index)
>>> print(s)
>>> res = stack(s, isstack=0)
>>> print(res)
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测试unstack参数，指定level
>>> index = pd.MultiIndex.from_tuples([('one', 'a'), ('one', 'b'), ('two', 'a'), ('two', 'b')])
>>> s = pd.Series(np.arange(1.0, 5.0), index=index)
>>> print(s)
>>> res = stack(s, isstack=0, level=0)
>>> print(res)
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