熊猫read_csv不会正确加载逗号分隔的CSV

Question

现在，我分析泰坦尼克号对Kaggel的挑战。 我的代码是这样的：

但我的理想输出是：

所以，我在去年的代码是

df["Age"].fillna(df.Age.median(), inplace=True) 

和错误发生

--------------------------------------------------------------------------- 
KeyError         Traceback (most recent call last) 
/Users/XXXi/anaconda/envs/py36/lib/python3.6/site-packages/pandas/indexes/base.py in get_loc(self, key, method, tolerance) 
    2133    try: 
-> 2134     return self._engine.get_loc(key) 
    2135    except KeyError: 

pandas/index.pyx in pandas.index.IndexEngine.get_loc (pandas/index.c:4433)() 

pandas/index.pyx in pandas.index.IndexEngine.get_loc (pandas/index.c:4279)() 

pandas/src/hashtable_class_helper.pxi in pandas.hashtable.PyObjectHashTable.get_item (pandas/hashtable.c:13742)() 

pandas/src/hashtable_class_helper.pxi in pandas.hashtable.PyObjectHashTable.get_item (pandas/hashtable.c:13696)() 

KeyError: 'Age' 

During handling of the above exception, another exception occurred: 

KeyError         Traceback (most recent call last) 
<ipython-input-4-9763f0a9951c> in <module>() 
----> 1 df["Age"].fillna(df.Age.median(), inplace=True) 

/Users/XXXi/anaconda/envs/py36/lib/python3.6/site-packages/pandas/core/frame.py in __getitem__(self, key) 
    2057    return self._getitem_multilevel(key) 
    2058   else: 
-> 2059    return self._getitem_column(key) 
    2060 
    2061  def _getitem_column(self, key): 

/Users/XXXi/anaconda/envs/py36/lib/python3.6/site-packages/pandas/core/frame.py in _getitem_column(self, key) 
    2064   # get column 
    2065   if self.columns.is_unique: 
-> 2066    return self._get_item_cache(key) 
    2067 
    2068   # duplicate columns & possible reduce dimensionality 

/Users/XXXi/anaconda/envs/py36/lib/python3.6/site-packages/pandas/core/generic.py in _get_item_cache(self, item) 
    1384   res = cache.get(item) 
    1385   if res is None: 
-> 1386    values = self._data.get(item) 
    1387    res = self._box_item_values(item, values) 
    1388    cache[item] = res 

/Users/XXXi/anaconda/envs/py36/lib/python3.6/site-packages/pandas/core/internals.py in get(self, item, fastpath) 
    3541 
    3542    if not isnull(item): 
-> 3543     loc = self.items.get_loc(item) 
    3544    else: 
    3545     indexer = np.arange(len(self.items))[isnull(self.items)] 

/Users/XXXi/anaconda/envs/py36/lib/python3.6/site-packages/pandas/indexes/base.py in get_loc(self, key, method, tolerance) 
    2134     return self._engine.get_loc(key) 
    2135    except KeyError: 
-> 2136     return self._engine.get_loc(self._maybe_cast_indexer(key)) 
    2137 
    2138   indexer = self.get_indexer([key], method=method, tolerance=tolerance) 

pandas/index.pyx in pandas.index.IndexEngine.get_loc (pandas/index.c:4433)() 

pandas/index.pyx in pandas.index.IndexEngine.get_loc (pandas/index.c:4279)() 

pandas/src/hashtable_class_helper.pxi in pandas.hashtable.PyObjectHashTable.get_item (pandas/hashtable.c:13742)() 

pandas/src/hashtable_class_helper.pxi in pandas.hashtable.PyObjectHashTable.get_item (pandas/hashtable.c:13696)() 

KeyError: 'Age' 

我用sep=','所以我真的不明白为什么这个代码不能在每个逗号分开。如何解决这个问题？

我跟着一个答案，但错误发生（我不知道为什么）

我的数据是

Answer 1

注意！

主要问题是下载数据。如果您遇到加载和处理Kaggle Titanic数据集的问题，您可以重新从here下载CSV并重新运行您的程序。

---

你可以通过delimiter=','：

df = pd.read_csv("Desktop/data/train.csv", delimiter=',') 
print(df.head()) 

    PassengerId Survived Pclass \ 
0   1   0  3 
1   2   1  1 
2   3   1  3 
3   4   1  1 
4   5   0  3 

               Name  Sex Age SibSp \ 
0       Braund, Mr. Owen Harris male 22.0  1 
1 Cumings, Mrs. John Bradley (Florence Briggs Th... female 38.0  1 
2        Heikkinen, Miss. Laina female 26.0  0 
3  Futrelle, Mrs. Jacques Heath (Lily May Peel) female 35.0  1 
4       Allen, Mr. William Henry male 35.0  0 

    Parch   Ticket  Fare Cabin Embarked 
0  0   A/5 21171 7.2500 NaN  S 
1  0   PC 17599 71.2833 C85  C 
2  0 STON/O2. 3101282 7.9250 NaN  S 
3  0   113803 53.1000 C123  S 
4  0   373450 8.0500 NaN  S 


print(df.columns) 

Index(['PassengerId', 'Survived', 'Pclass', 'Name', 'Sex', 'Age', 'SibSp', 
     'Parch', 'Ticket', 'Fare', 'Cabin', 'Embarked'], 
     dtype='object') 

接下来，您可以创建各种各样的映射：

mapping = {'male' : 0, 'female' : 1} 

而且你会打电话给pd.Series.replace：

df.Sex = df.Sex.replace(mapping) 
print(df.Sex) 

0 0 
1 1 
2 1 
3 1 
4 0 
Name: Sex, dtype: int64 

Answer 2

你read_csv看起来不错，在同一直线上替换似乎导致麻烦。

尝试先将csv读入变量df中。这样你的代码就会更干净。

df = pd.read_csv('Desktop/data/train.csv',sep=',') 
df['Sex'] = df['Sex'].map({'female': 1, 'male': 0}) 

但是你可以离开这个月的说法完全为逗号是标准的分隔符

或者做清洁与更换上新的生产线，你文件读入到DF和使用后 inplace=True：

df['Sex'].replace({'male': 0, 'female': 1}, inplace=True) 

一般建议：

Kaggle我们bpage支持在内核部分进行脚本共享和注释。 试着看一下就看你如何去分析，如果你卡住的地方：

https://www.kaggle.com/c/titanic/kernels