带有 isin 的 pandas 函数
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pandas function with isin
提问by Kvothe
I have a dataframe as like this:
我有一个像这样的数据框：
aa bb cc
[a, x, y] a 1
[b, d, z] b 2
[c, e, f] s 3
np.nan d 4
I'm trying to create a new column like this:
我正在尝试创建一个这样的新列：
aa bb cc dd
[a, x, y] a 1 True
[b, d, z] b 2 True
[c, e, f] s 3 False
np.nan d 4 False
My current solution is:
我目前的解决方案是：
def some_function(row):
if row['bb].isin(row['aa'])==True:
return True
return False
df['dd'] = df.apply(lambda row: some_function(row), axis=1)
But this throws out an error ("'str' object has no attribute 'isin'", 'occurred at index 0')
但这会抛出一个错误 ("'str' object has no attribute 'isin'", 'occurred at index 0')
I suspect, because I'm missing something when it comes to checking the isin.
我怀疑，因为在检查isin.
Essentially, I need to check if the str value of bbis in column aawhich has a list in each cell.
本质上，我需要检查的 str 值bb是否aa在每个单元格中有一个列表的列中。
Any ideas on how to do this?
关于如何做到这一点的任何想法？
回答by jezrael
You need parameter infor check membership in list:
您需要参数in来检查列表中的成员资格：
df['dd'] = df.apply(lambda x: x.bb in x.aa, axis=1)
print (df)
aa bb cc dd
0 [a, x, y] a 1 True
1 [b, d, z] b 2 True
2 [c, e, f] s 3 False
EDIT:
编辑：
df['dd'] = df.apply(lambda x: (x.bb in x.aa) and (x.cc == 1), axis=1)
print (df)
aa bb cc dd
0 [a, x, y] a 1 True
1 [b, d, z] b 2 False
2 [c, e, f] s 3 False
Or:
或者：
df['dd'] = df.apply(lambda x: x.bb in x.aa, axis=1) & (df['cc'] == 1)
print (df)
aa bb cc dd
0 [a, x, y] a 1 True
1 [b, d, z] b 2 False
2 [c, e, f] s 3 False
EDIT:
编辑：
df['dd'] = df.apply(lambda x: x.bb in x.aa if type(x.aa) == list else False, axis=1)
print (df)
aa bb cc dd
0 [a, x, y] a 1 True
1 [b, d, z] b 2 True
2 [c, e, f] s 3 False
4 NaN d 4 False
