python - 过滤掉包含特定字符串的数据帧的行

Question

我有一个庞大的数据框。数据框有 patient.drug 列。此列包含字典列表作为其元素。我想过滤掉 patient.drug 列中所有包含“NIFEDIPINE”字样的行。

数据框非常大。这是它的一个示例。

                                                         patient.drug
0                       [{'drugcharacterization': '1', 'medicinalproduct': 'PANDOL'}]
1                       [{'drugcharacterization': '2', 'medicinalproduct': 'NIFEDIPINE'}]      
2                       [{'drugcharacterization': '3', 'medicinalproduct': 'SIMVASTATIN'}]
3                       [{'drugcharacterization': '4', 'medicinalproduct': 'NIFEDIPINE'}]      

到目前为止，我已经尝试过了

df[df['patient.drug'].str.contains('NIFEDIPINE')]

但它给我一个错误。

 raise KeyError(f"None of [{key}] are in the [{axis_name}]")

KeyError: "None of [Float64Index([nan, nan, nan, nan, nan, nan, nan, nan, nan, nan,\n              ...\n              nan, nan, nan, nan, nan, nan, nan, nan, nan, nan],\n             dtype='float64', length=12000)] are in the [columns]"

我也尝试过使用 in 运算符并遍历行。

lst=[]
for i in range(len(df)):
    if 'NIFEDIPINE' in df.loc[i, "patirnt.drug"]:
        lst.append(i)
print(lst)

这也给我一个错误。我应该怎么做才能正确处理？

Answer 1

复制您的数据后，

>>> df
                                                         patient.drug
0  [{'drugcharacterization': '1', 'medicinalproduct': 'PANDOL'}]
1  [{'drugcharacterization': '2', 'medicinalproduct': 'NIFEDIPINE'}]
2  [{'drugcharacterization': '3', 'medicinalproduct': 'SIMVASTATIN'}]
3  [{'drugcharacterization': '3', 'medicinalproduct': 'SIMVASTATIN'}]
4  [{'drugcharacterization': '4', 'medicinalproduct': 'NIFEDIPINE'}]

在使用您的代码时:

>>> df[df['patient.drug'].str.contains('NIFEDIPINE')]

错误:

    raise KeyError(f"None of [{key}] are in the [{axis_name}]")
KeyError: "None of [Float64Index([nan, nan, nan, nan, nan], dtype='float64')] are in the [columns]"

解决方案:

    >>> df[df['patient.drug'].astype('str').str.contains('NIFEDIPINE')]
                                                        patient.drug
1  [{'drugcharacterization': '2', 'medicinalproduct': 'NIFEDIPINE'}]
4  [{'drugcharacterization': '4', 'medicinalproduct': 'NIFEDIPINE'}]

注意:

这是由于 indexer 检查 pandas indexer.py 部分而引发的问题，如下所示:

--> pandas/core/indexing.py

# Count missing values:
missing_mask = indexer < 0
missing = (missing_mask).sum()

if missing:
    if missing == len(indexer):
        axis_name = self.obj._get_axis_name(axis)
        raise KeyError(f"None of [{key}] are in the [{axis_name}]")

    # We (temporarily) allow for some missing keys with .loc, except in
    # some cases (e.g. setting) in which "raise_missing" will be False