Python Pandas：AttributeError：'str'对象没有属性'loc'

Question

Working with dataframe df: 使用数据框df：

Count
1
2
3
4
5

Want to add second column, that categorizes everything above 3 as '4+' - needed output: 要添加第二列，将高于3的所有内容归类为“ 4+”-所需的输出：

Count | Category
1        1
2        2
3        3
4        4+
5        4+

This is my code: 这是我的代码：

df['Category'] = df['Count']
df = df.loc[df['Count'] > 3, 'Category'] = '4+'

And I get this error: 我得到这个错误：

AttributeError: 'str' object has no attribute 'loc'

Answer 1

Just go with 随便去吧

df['Category'] = df['Count']
df.loc[df['Count'] > 3, 'Category'] = '4+'

Answer 2

You can try out with: 您可以尝试以下方法：

import pandas as pd
df = pd.DataFrame({"Count": [1,2,3,4,5]})
df["Category"] = df["Count"].apply(str)
df["Category"][df['Count'] > 3] = "4+"

Output would be: 输出为：

>>> df
   Count Category
0      1        1
1      2        2
2      3        3
3      4       4+
4      5       4+

Python Pandas：AttributeError：&#39;str&#39;对象没有属性&#39;loc&#39;