假设我有一列的数据框：
df = pd.DataFrame(np.random.randint(0,9,size=(100, 1)), columns=['number'])
我有两个列表，一个列表包含偶数，另一个包含奇数。
odd_numbers = [1,3,5,7,9]
even_numbers = [0,2,4,6,8]
我想根据df ['number']中的值在数据框上创建另一个系列，说“偶数”或“奇数”
就像是：
df['odd_or_even'] = 'even' if df[number].isin(even_numbers)
df['odd_or_even'] = 'odd' if df[number].isin(odd_numbers)
我认为您可以使用numpy.where：
import pandas as pd
import numpy as np
df = pd.DataFrame(np.random.randint(0,9,size=(100, 1)), columns=['number'])
df['odd_or_even'] = np.where(df.number % 2, 'odd', 'even')
print (df)
number odd_or_even
0 1 odd
1 0 even
2 4 even
3 5 odd
4 0 even
5 0 even
6 1 odd
7 0 even
8 7 odd
9 8 even
通过评论编辑
用途loc：
import pandas as pd
import numpy as np
df = pd.DataFrame(np.random.randint(0,9,size=(20, 1)), columns=['number'])
odd_numbers = [1,3,5,7,9]
even_numbers = [0,2,4,6,8]
df.loc[df.number.isin(odd_numbers), 'odd_or_even'] = 'odd'
df.loc[df.number.isin(even_numbers), 'odd_or_even'] = 'even'
print (df)
number odd_or_even
0 5 odd
1 1 odd
2 2 even
3 3 odd
4 5 odd
5 6 even
6 3 odd
7 4 even
8 2 even
9 8 even
10 8 even
11 1 odd
12 2 even
13 1 odd
14 3 odd
15 3 odd
16 5 odd
17 4 even
18 2 even
19 5 odd
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