python - Pandas Dataframe - 条件列创建

Question

我正在尝试根据另一列的条件逻辑创建一个新列。我尝试过搜索，但未能找到任何可以解决我的问题的内容。

我已将 CSV 导入到 pandas 数据框中，其结构如下。我编辑了这篇文章的一些描述，但除此之外一切都是一样的:

#code used to load dataframe:
df = pd.read_csv(r"C:\filepath\filename.csv")

#output from print(type(df)):
#class 'pandas.core.frame.DataFrame'

#output from print(df.columns.values):
#['Type' 'Trans Date' 'Post Date' 'Description' 'Amount'] 

#output from print(df.columns):
    Index(['Type', 'Trans Date', 'Post Date', 'Description', 'Amount'], dtype='object')
#output from print

Type  Trans Date   Post Date            Description  Amount
0  Sale  01/25/2018  01/25/2018                  DESC1  -13.95

1  Sale  01/25/2018  01/26/2018   AMAZON MKTPLACE PMTS   -6.99

2  Sale  01/24/2018  01/25/2018          SUMMIT BISTRO   -5.85

3  Sale  01/24/2018  01/25/2018                  DESC3   -9.13

4  Sale  01/24/2018  01/26/2018    DYNAMIC VENDING INC   -1.60

然后我编写以下代码:

def criteria(row):
    if row.Description.find('SUMMIT BISTRO')>0:
        return 'Lunch'
    elif row.Description.find('AMAZON MKTPLACE PMTS')>0:
        return 'Amazon'
    elif row.Description.find('Aldi')>0:
        return 'Groceries'
    else:
        return 'NotWorking'

df['Category'] = df.apply(criteria, axis=0)

错误:

Traceback (most recent call last):
File "C:\Users\Test_BankReconcile2.py", line 44, in <module>
df['Category'] = df.apply(criteria, axis=0)
  File "C:\Users\Anaconda3\lib\site-packages\pandas\core\frame.py", line 4262, in apply
ignore_failures=ignore_failures)
  File "C:\Users\Anaconda3\lib\site-packages\pandas\core\frame.py", line 4358, in _apply_standard
results[i] = func(v)
  File "C:\Users\OneDrive\Documents\finance\Test_BankReconcile2.py", line 35, in criteria
if row.Description.find('SUMMIT BISTRO')>0:
  File "C:\Users\Anaconda3\lib\site-packages\pandas\core\generic.py", line 3081, in __getattr__
    return object.__getattribute__(self, name)
AttributeError: ("'Series' object has no attribute 'Description'", 'occurred at index Type')

我能够在来自不同银行的非常相似的 csv 文件上成功执行相同类型的命令(此示例来 self 的信用卡)，所以我不知道发生了什么，但可能我需要以某种我没有做的方式定义数据框？或者可能还有其他一些我没有看到的非常明显的东西？预先感谢大家帮助我解决这个问题。

Answer 1

是的，您的问题是您需要将 axis=1 传递给 .apply:

In [52]: df
Out[52]:
   Type  Trans Date   Post Date           Description  Amount
0  Sale  01/25/2018  01/25/2018                 DESC1  -13.95
1  Sale  01/25/2018  01/26/2018  AMAZON MKTPLACE PMTS   -6.99
2  Sale  01/24/2018  01/25/2018         SUMMIT BISTRO   -5.85
3  Sale  01/24/2018  01/25/2018                 DESC3   -9.13
4  Sale  01/24/2018  01/26/2018   DYNAMIC VENDING INC   -1.60

In [53]: def criteria(row):
    ...:     if row.Description.find('SUMMIT BISTRO')>0:
    ...:         return 'Lunch'
    ...:     elif row.Description.find('AMAZON MKTPLACE PMTS')>0:
    ...:         return 'Amazon'
    ...:     elif row.Description.find('Aldi')>0:
    ...:         return 'Groceries'
    ...:     else:
    ...:         return 'NotWorking'
    ...:

In [54]: df.apply(criteria, axis=1)
Out[54]:
0    NotWorking
1    NotWorking
2    NotWorking
3    NotWorking
4    NotWorking
dtype: object

第二个问题是你有一个逻辑错误，而不是 .find(x) > 0 你想要 .find(x) >= 0 ，或者更好, some_other_string 中的 some_string