在python2.7中比较timestamp和datetime64时的奇怪行为

pandas numpy b<a

class TestCom(int):
    def __init__(self, a):
    self.value = a

    def __gt__(self, other):
    print('TestComp __gt__ called')
    return True

    def __eq__(self, other):
    return self.a == other

__gt__ < __eq__ ==

a = TestCom(9)
print(a)
# Output: 9

# my def of __ge__
a > 100

# Ouput: TestComp __gt__ called
# True

a > '100'
# Ouput: TestComp __gt__ called
# True

'100' < a

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-486-8aee1b1d2500> in <module>()
      1 # this will not use my def of __ge__
----> 2 '100' > a

TypeError: '>' not supported between instances of 'str' and 'TestCom'

timestamps_sourceCode pandas.Timestamp

pd.Timestamp np.datetime64 Timestamp.__richcmp__

# we can do the following to have a comparison of say b > a
# this converts a to np.datetime64 - .asm8 is equivalent to .to_datetime64()
b > a.asm8

# or we can confert b to datetime64[ms]
b.astype('datetime64[ms]') > a

# or convert to timestamp
pd.to_datetime(b) > a

nanoseconds

a = pd.Timestamp('2013-03-24 05:32:00.00000001')
a.nanosecond   # returns 10
# doing the comparison again where they're both ns still fails
b < a

!=

a = pd.Timestamp('2013-03-24 05:32:00.00000000')
b = np.datetime64('2013-03-24 05:32:00.00000000', 'ns')

b == a  # returns False

a == b  # returns True

False True

nanosecond 0.23.0 pd.Timestamp('2013-03-23T05:33:00.000000022', unit='ns') ns

SO_Datetime Timestamp datetime _compare_outside_nanorange

SO int64

1 > a
a > 1

Cannot compare type 'Timestamp' with type 'int'

b > a int np.greater() np.greater ufunc_docs

a == b b == a b Flase

123 == '123'