如何根据 Pandas (python) 中的列表设置值
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How to set values based on a list in Pandas (python)
提问by SteelyDanish
I have a maybe a hopefully easy question that I wasn't able to find an answer on stack.
我有一个可能很简单的问题，我无法在堆栈中找到答案。
I have a a dataframe (df) and I want to set a value (some_value) if a value from the column 'month' is in a list (some_list).
我有一个数据框 (df)，如果“月”列中的值在列表 (some_list) 中，我想设置一个值 (some_value)。
e.g.
例如
df[df['month'].isin(some_list)] = some_value
df[df['month'].isin(some_list)] = some_value
It's barfing up an AttributeError: 'int' object has no attribute 'view'.
它引发了一个 AttributeError: 'int' object has no attribute 'view'。
Any helpful direction would be awesome.
任何有用的方向都会很棒。
[edit]:
[编辑]：
some_list = [4,5,6,7]
some_value = 100
df.month is a value from 1 - 12
df.month 是 1 - 12 之间的值
df.columns = ['datetime','weekday','hour','month','value']
df.columns = ['datetime','weekday','hour','month','value']
I realize I also want to find out the index of the rows which isin some_list then use those indices to set the value of another column ('value') to some_value. Apologies for not writing that originally.
我意识到我还想找出 some_list 中的行的索引，然后使用这些索引将另一列的值（'value'）设置为 some_value。为最初没有写那个而道歉。
回答by Marius
Your question still doesn't seem to have enough information to find the real problem. This quick example shows that your attempt can work just fine:
您的问题似乎仍然没有足够的信息来找到真正的问题。这个快速示例表明您的尝试可以正常工作：
import pandas as pd
df = pd.DataFrame({'x': [4, 5, 6], 'month': [1, 2, 3]})
some_list = [2, 3]
df[df['month'].isin(some_list)] = 99
df
Out[13]:
month x
0 1 4
1 99 99
2 99 99
...suggesting that your problem is more likely because you've mixed up the types of your variables. Currently the only thing I can suggest is only doing the assignment to specific columns, as you may be trying to assign an int value to a datetime column or something, e.g.:
...表明您的问题更有可能是因为您混淆了变量的类型。目前我唯一能建议的就是只对特定列进行分配，因为您可能试图将 int 值分配给日期时间列或其他内容，例如：
df = pd.DataFrame({'x': [4, 5, 6], 'month': [1, 2, 3]})
some_list = [2, 3]
df.loc[df['month'].isin(some_list), 'x'] = 99
df
Out[14]:
month x
0 1 4
1 2 99
2 3 99
