python - 从数据框列检查字符串是否为 nan

Question

当我打印 data['words'].values 时从数据框中得到，

['from' 'fairest' 'creatures' 'we' 'desire' 'increase' nan 'that' 'thereby']

当我像这样循环时，如何识别值是否为 nan？

for w in data['words'].values:
    check if w is nan ????

Answer 1

使用 pandas 方法 isnull测试:

In [45]:

df = pd.DataFrame({'words':['from', 'fairest', 'creatures' ,'we' ,'desire', 'increase' ,nan ,'that' ,'thereby']})
df
Out[45]:
       words
0       from
1    fairest
2  creatures
3         we
4     desire
5   increase
6        NaN
7       that
8    thereby
In [46]:

pd.isnull(df['words'])
Out[46]:
0    False
1    False
2    False
3    False
4    False
5    False
6     True
7    False
8    False
Name: words, dtype: bool