将python数据帧转换为列表
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convert python dataframe to list
提问by user1452849
I have a Python dataFrame with multiple columns.
我有一个包含多列的 Python 数据框。
LogBlk Page BayFail
0 0 [0, 1, 8, 9]
1 16 [0, 1, 4, 5, 6, 8, 9, 12, 13, 14]
2 32 [0, 1, 4, 5, 6, 8, 9, 12, 13, 14]
3 48 [0, 1, 4, 5, 6, 8, 9, 12, 13, 14]
I want to find BayFails that is associated with LogBlk=0, and Page=0.
我想找到与 LogBlk=0 和 Page=0 关联的 BayFails。
df2 = df[ (df['Page'] == 16) & (df['LogBlk'] == 0) ]['BayFail']
This will return [0,1,8,9]
这将返回 [0,1,8,9]
What I want to do is to convert this pandas.series into a list. Does anyone know how to do that?
我想要做的是将这个 pandas.series 转换成一个列表。有谁知道这是怎么做到的吗？
回答by unutbu
pandas.Series, has a tolistmethod:
pandas.Series，有一个tolist方法：
In [10]: import pandas as pd
In [11]: s = pd.Series([0,1,8,9], name = 'BayFail')
In [12]: s.tolist()
Out[12]: [0L, 1L, 8L, 9L]
Technical note: In my original answer I said that Serieswas a subclass of numpy.ndarrayand inherited its tolistmethod. While that's true for Pandas version 0.12 or older, In the soon-to-be-released Pandas version 0.13, Serieshas been refactored to be a subclass of NDFrame. Seriesstill has a tolistmethod, but it has no direct relationship to the numpy.ndarraymethod of the same name.
技术说明：在我最初的回答中，我说这Series是一个子类numpy.ndarray并继承了它的tolist方法。虽然这对于 Pandas 0.12 或更早版本是正确的，但在即将发布的 Pandas 0.13 版本中，Series已被重构为NDFrame. Series仍然有一个tolist方法，但它numpy.ndarray与同名方法没有直接关系。
回答by unutbu
You can also convert them to numpy arrays
您也可以将它们转换为 numpy arrays
In [124]: s = pd.Series([0,1,8,9], name='BayFail')
In [125]: a = pd.np.array(s)
Out[125]: array([0, 1, 8, 9], dtype=int64)
In [126]: a[0]
Out[126]: 0
