Question

是否有一种优雅的方法可以根据pandas中数据框中的多个列来分配值？我们假设我有一个包含2列的数据框：FruitType和Color。

import pandas as pd
df = pd.DataFrame({'FruitType':['apple', 'banana','kiwi','orange','loquat'],
'Color':['red_black','yellow','greenish_yellow', 'orangered','orangeyellow']})

我想基于＆＃39; FruitType＆＃39;分配第三列的值，＆＃39; isYellowSeedless＆＃39;和＆＃39;颜色＆＃39;列。

我有一个水果清单，我认为它是无籽的，并且想检查颜色列，看它是否包含str＆＃34;黄色＆＃34;。

seedless = ['banana', 'loquat']

如何优雅地将这一切串联起来？

这是我没有尝试过的尝试：

df[(df['FruitType'].isin(seedless)) & (culture_table['Color'].str.contains("yellow"))]['isYellowSeedless'] = True

Answer 1

将loc与mask：

一起使用

m = (df['FruitType'].isin(seedless)) & (df['Color'].str.contains("yellow"))

df.loc[m, 'isYellowSeedless'] = True
print (df)
             Color FruitType isYellowSeedless
0        red_black     apple              NaN
1           yellow    banana             True
2  greenish_yellow      kiwi              NaN
3        orangered    orange              NaN
4     orangeyellow    loquat             True

如果需要True和False输出：

df['isYellowSeedless'] = m
print (df)
             Color FruitType  isYellowSeedless
0        red_black     apple             False
1           yellow    banana              True
2  greenish_yellow      kiwi             False
3        orangered    orange             False
4     orangeyellow    loquat              True

对于某些标量的if-else，请使用numpy.where：

df['isYellowSeedless'] = np.where(m, 'a', 'b')
print (df)
             Color FruitType isYellowSeedless
0        red_black     apple                b
1           yellow    banana                a
2  greenish_yellow      kiwi                b
3        orangered    orange                b
4     orangeyellow    loquat                a

转换为0和1：

df['isYellowSeedless'] = m.astype(int)
print (df)
             Color FruitType  isYellowSeedless
0        red_black     apple                 0
1           yellow    banana                 1
2  greenish_yellow      kiwi                 0
3        orangered    orange                 0
4     orangeyellow    loquat                 1

Answer 2

或者你可以尝试

df['isYellowSeedless']=df.loc[df.FruitType.isin(seedless),'Color'].str.contains('yellow')
df
Out[546]: 
             Color FruitType isYellowSeedless
0        red_black     apple              NaN
1           yellow    banana             True
2  greenish_yellow      kiwi              NaN
3        orangered    orange              NaN
4     orangeyellow    loquat             True

如何根据pandas中的多个列分配值？

2 个答案: