如何把python集合中的空值删除
import pandas as pd
import numpy as np
df=pd.DataFrame({'a':[1,np.nan],
'b':['x',np.nan]})
s1=set(df['a'])
s2=set(df['b'])
s1.remove(np.nan)
s2.remove(np.nan)
print(s1,s2)
import pandas as pd
import numpy as np
df=pd.DataFrame({'a':[1,np.nan],
'b':['x',np.nan]})
s1=set(df['a'])
s2=set(df['b'])
s1.remove(np.nan)
s2.remove(np.nan)
print(s1,s2)
import pandas as pd
import numpy as np
import math
df=pd.DataFrame({'a':[1,np.nan],
'b':['x',np.nan]})
s1=set(df['a'])
s2=set(df['b'])
s1 = set([x for x in s1 if not math.isnan(x)])
print(s1)