如何在Pandas中创建SparseDataFrame？

Question

在编程中，有时候我们需要让程序做一些事情，比如计算、显示信息或者处理数据。为了实现这些功能，我们会用到一些代码块，这些代码块就像是程序的“指令”，告诉计算机该怎么做。

在这个例子中，

pandas.DataFrame(a)
Out[41]: 
   1   2   3
0  1   2 NaN
1  1 NaN   3

a = [{1:1.0,2:2.0}, {1:1.0,3:3.0}]

pandas.DataFrame(a)
Out[43]: 
   1   2   3
0  1   2 NaN
1  1 NaN   3

pandas.SparseDataFrame(a)
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-44-50288c1b1994> in <module>()
----> 1 pandas.SparseDataFrame(a)

/Library/Python/2.7/site-packages/pandas/sparse/frame.pyc in __init__(self, data, index, columns, default_kind, default_fill_value)
     94             sdict, columns, index = self._init_dict(data, index, columns)
     95         elif isinstance(data, (np.ndarray, list)):
---> 96             sdict, columns, index = self._init_matrix(data, index, columns)
     97         elif isinstance(data, DataFrame):
     98             sdict, columns, index = self._init_dict(data, data.index,

/Library/Python/2.7/site-packages/pandas/sparse/frame.pyc in _init_matrix(self, data, index, columns, dtype)
    203 
    204         data = dict([(idx, data[:, i]) for i, idx in enumerate(columns)])
--> 205         return self._init_dict(data, index, columns, dtype)
    206 
    207     def __array_wrap__(self, result):

/Library/Python/2.7/site-packages/pandas/sparse/frame.pyc in _init_dict(self, data, index, columns, dtype)
    174                     v = [v.get(i, nan) for i in index]
    175 
--> 176                 v = sp_maker(v)
    177             sdict[k] = v
    178 

/Library/Python/2.7/site-packages/pandas/sparse/frame.pyc in <lambda>(x)
    159                                           kind=self.default_kind,
    160                                           fill_value=self.default_fill_value,
--> 161                                           copy=True)
    162 
    163         sdict = {}

/Library/Python/2.7/site-packages/pandas/sparse/series.pyc in __new__(cls, data, index, sparse_index, kind, fill_value, name, copy)
    127             if sparse_index is None:
    128                 values, sparse_index = make_sparse(data, kind=kind,
--> 129                                                    fill_value=fill_value)
    130             else:
    131                 values = data

/Library/Python/2.7/site-packages/pandas/sparse/array.pyc in make_sparse(arr, kind, fill_value)
    426 
    427     if np.isnan(fill_value):
--> 428         mask = -np.isnan(arr)
    429     else:
    430         mask = arr != fill_value

TypeError: ufunc 'isnan' not supported for the input types, and the inputs could not be safely coerced to any supported types according to the casting rule 'safe'

就是一个代码块的占位符，里面会放一些具体的代码。代码的内容可能会涉及到变量、函数或者其他编程概念，但具体的内容在这里没有给出。

总之，代码块是编程中非常重要的部分，它们帮助我们把想法变成实际的操作，让计算机能够理解并执行我们的指令。

数据结构数据处理编程概念代码块 pandas sparsedataframe 变量与函数

如何在Pandas中创建SparseDataFrame？

1 个回答

pandas 版本 >= 1.0

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