無法將字符串轉換為浮點 - 對象類型

Question

我正在使用 Pandas 和 Jupyter Notebook 在 Python 中處理數據框，並且我的數據框具有經度和緯度列，其值類似於“-23,4588”。 不知何故，每次我嘗試將它轉換為浮點數時，我都會收到一條錯誤消息，告訴“無法將字符串轉換為浮點數”。

我嘗試更改逗號，嘗試將 .csv 列類型更改為浮動，但沒有任何效果。

我的代碼的一部分：

ValueError                                Traceback (most recent call last)
C:\TEMP/ipykernel_12640/4061618161.py in <module>
----> 1 newocorr_sjc['Latitude'] = newocorr_sjc['Latitude'].astype(float)

c:\users\caique.fernandes\appdata\local\programs\python\python39\lib\site-packages\pandas\core\generic.py in astype(self, dtype, copy, errors)
   5875         else:
   5876             # else, only a single dtype is given
-> 5877             new_data = self._mgr.astype(dtype=dtype, copy=copy, errors=errors)
   5878             return self._constructor(new_data).__finalize__(self, method="astype")
   5879 

c:\users\caique.fernandes\appdata\local\programs\python\python39\lib\site-packages\pandas\core\internals\managers.py in astype(self, dtype, copy, errors)
    629         self, dtype, copy: bool = False, errors: str = "raise"
    630     ) -> "BlockManager":
--> 631         return self.apply("astype", dtype=dtype, copy=copy, errors=errors)
    632 
    633     def convert(

c:\users\caique.fernandes\appdata\local\programs\python\python39\lib\site-packages\pandas\core\internals\managers.py in apply(self, f, align_keys, ignore_failures, **kwargs)
    425                     applied = b.apply(f, **kwargs)
    426                 else:
--> 427                     applied = getattr(b, f)(**kwargs)
    428             except (TypeError, NotImplementedError):
    429                 if not ignore_failures:

c:\users\caique.fernandes\appdata\local\programs\python\python39\lib\site-packages\pandas\core\internals\blocks.py in astype(self, dtype, copy, errors)
    671             vals1d = values.ravel()
    672             try:
--> 673                 values = astype_nansafe(vals1d, dtype, copy=True)
    674             except (ValueError, TypeError):
    675                 # e.g. astype_nansafe can fail on object-dtype of strings

c:\users\caique.fernandes\appdata\local\programs\python\python39\lib\site-packages\pandas\core\dtypes\cast.py in astype_nansafe(arr, dtype, copy, skipna)
   1095     if copy or is_object_dtype(arr) or is_object_dtype(dtype):
   1096         # Explicit copy, or required since NumPy can't view from / to object.
-> 1097         return arr.astype(dtype, copy=True)
   1098 
   1099     return arr.view(dtype)

ValueError: could not convert string to float: '-23,5327'```

Answer 1

也許你應該使用decimal=','作為pd.read_csv參數：

>>> df.read('data.csv', decimal=',')

或replace ',' replace為 '.'：

>>> df.replace(r'(\d+),(\d+)', r'\1.\2', regex=True)