为什么当过滤器为
Project ID
== None时,此过滤器不起作用?我还注意到is None
而不是== None
会返回KeyError: False
。import pandas as pd
df = pd.DataFrame(data = [['Project1', 'CT', 800], [None, 3, 1000], ['Project3', 'CA', 20]], columns=['Project ID', 'State', 'Cost'])
print df.loc[df['Project ID'] == 'Project1'].values
print df.loc[df['Project ID'] == None].values
输出:
[['Project1' 'CT' 800L]]
[]