python中的正无穷或负无穷,使用float("inf")或float("-inf")来表示。 这里有点特殊,写成:float("inf"),float("INF")或者float('Inf')都是可以的。 当涉及 > 和 < 比较时,所有数都比无穷小float("-inf")大,所有数都比无穷大float("inf")小。 相等比较时,float("+inf")与float("+inf")、float("...
In [58]: data2.isnull()Out[58]:a Trueb Falsec Falsed Falsedtype: boolIn [59]: data2.notnull()Out[59]:a Falseb Truec Trued Truedtype: boolIn [60]: data2[data2.isnull()==True] #嵌套查询NaNOut[60]:a NaNdtype: float64In [64]: data2.count() #统计非NaN个数Out[64]: ...
fabs(1 - 2)) def test_isfinite(self): self.assertTrue(math.isfinite(456789)) self.assertFalse(math.isfinite(float('inf'))) self.assertFalse(math.isfinite(float('nan'))) def tearDown(self): print("tearDown Func ...") if __name__ == '__main__': unittest.main() 可以通过...
print('y == nan =', y == float('nan')) print('isnan(y) =', math.isnan(y)) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. nan不与任何值相等,包括它本身,所以需用isnan()检查nan。 $ python3 math_isnan.py x = inf isnan(x) = False y = x / x = nan y == nan ...
tuple_test=[]print(bool(tuple_test)) tuple_test={}print(bool(tuple_test)) ifnotxxx: 在使用列表的时候,如果你想区分x==[]和x==None两种情况的话, 此时if not x:将会出现问题: x=[] y=Noneprint('not x:%s'%(notx))print('not y:%s'%(noty))print('')print('x is None:%s'%(xis...
pandas python -检查字典中是否有nan floatNaN很奇怪，因为NaN！= NaN。这是有原因的，但它仍然会破坏...
id int64 date datetime64[ns] city object category object age int64 price float64 dtype: object 四、查看空值 import pandas as pd df = pd.DataFrame(pd.read_excel('test.xlsx', engine='openpyxl')) print(df.isnull()) id date city category age price False False False False False False False...
importnumpyasnpdeftest(a):a[0]=np.nanm=[1,2,3]test(m)print(m) output: [nan, 2, 3] Note python has this really weird error if you define local variable in a function same name as the global variable, program will promptUnboundLocalError. ...
Two'].fillna(df['One']) Out[4]: 0 21 1 11 2 25 Name: Two, dtype: float64
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