Pandas 应用函数抛出 NotImplementedError

Question

我有一个非常基本的 df，我想根据一列的某些正则表达式创建 2 个新列。我创建了一个函数来执行此操作，它返回 2 个值。

def get_value(s):
    result = re.findall('(?<=Value":")(\d+)\.(\d+)?(?=")', s)
    if len(result) != 2:
        return -1, -1
    else:
        matches = []
        for match in result:
            matches.append(match[0] + '.' + match[1])
        return  float(matches[0]), float(matches[1])

当我尝试这个时：data['Test1'], data['Test2'] = zip(*data['mod_data'].apply(get_value))

它抛出一个错误“NotImplementedError：isna is not defined for MultiIndex”，但如果我把它分成 2 个 diff 函数，它就可以工作。

def get_value1(s):
    result = re.findall('(?<=Value":")(\d+)\.(\d+)?(?=")', s)
    if len(result) != 2:
        return -1
    else:
        matches = []
        for match in result:
            matches.append(match[0] + '.' + match[1])
        return  float(matches[0])

def get_value2(s):
    result = re.findall('(?<=Value":")(\d+)\.(\d+)?(?=")', s)
    if len(result) != 2:
        return -1
    else:
        matches = []
        for match in result:
            matches.append(match[0] + '.' + match[1])
        return float(matches[1])


data['From'] = data['mod_data'].apply(get_value1)
data['To'] = data['mod_data'].apply(get_value2)

另一件需要注意的事情是在最后抛出错误 NotImplementedError。我在我的 get_value 函数中添加了 print 语句，它在计算完最后一行后被抛出。

编辑：添加了我正在处理的示例 df

test = pd.DataFrame([['A', 'A1', 'Top', '[{"Value":"37.29","ID":"S1234.1","Time":"","EXPTIME_Name":"","Value":"37.01"}]'], 
                     ['B', 'B1', 'Bottom', '[{"EXPO=T10;PID=.ABCDE149;"Value":"45.29";RETICLEID=S14G1490Y2;SEQ=5A423002",Value":"56.98"}]']],
                     columns=['Module', 'line', 'area', 'mod_data'])

期望的结果：

  Module line  ...   From     To
0      A   A1  ...  37.29  37.01
1      B   B1  ...  45.29  56.98

Answer 1

首先，您的正则表达式有点不对劲。将 '(?<=Value":")(\d+)\.(\d+)?(?=")' 更改为 '(?<=Value":")(\d+\.\d+)?(?=")'，以便完整的浮点数位于一个捕获组中。您将小数点前的部分分成一组，将小数点后的部分分成另一组：

然后，您可以使用str.findall:

test = pd.DataFrame([['A', 'A1', 'Top', '[{"Value":"37.29","ID":"S1234.1","Time":"","EXPTIME_Name":"","Value":"37.01"}]'], 
                     ['B', 'B1', 'Bottom', '[{"EXPO=T10;PID=.ABCDE149;"Value":"45.29";RETICLEID=S14G1490Y2;SEQ=5A423002",Value":"56.98"}]']],
                     columns=['Module', 'line', 'area', 'mod_data'])
test[['From', 'To']] = test['mod_data'].str.findall('(?<=Value":")(\d+\.\d+)?(?=")')
test
Out[1]: 
  Module line    area                                           mod_data  \
0      A   A1     Top  [{"Value":"37.29","ID":"S1234.1","Time":"","EX...   
1      B   B1  Bottom  [{"EXPO=T10;PID=.ABCDE149;"Value":"45.29";RETI...   

    From     To  
0  37.29  37.01  
1  45.29  56.98

Pandas 应用函数抛出 NotImplementedError

Pandas apply function throws NotImplementedError

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