Daniel Konstantinov

简化:

def my_in(obj, container):
    for elem in container:
        if bool(my_compare_equal(obj, elem)):
            return True
    return False

def my_compare_equal(obj, elem):
    if id(obj) == id(elem):
        return True
    return obj.__eq__(elem)

有关更多数据,请参阅 list_contains 然后 PyObject_RichCompareBool , PyObject_RichCompare , do_richcompare

“伪执行”步骤:

c = [AA('x', np.arange(3)),
     AA('x', np.arange(3)),
     AA('y', np.arange(3))]

c[0] in c
# explain:
my_in(obj=c[0], container=c)
    # for loop:
    
    # 0-iteration:
    # elem = c[0]
    my_compare_equal(obj=c[0], elem=c[0])
        # (id(c[0]) == id(c[0])) == True
        # --> True
    bool(True)
        # True.__bool__()
        # --> True
    # --> True

c[1] in c
# explain:
my_in(obj=c[1], container=c)
    # for loop:

    # 0-iteration:
    # elem = c[0]
    my_compare_equal(obj=c[1], elem=c[0])
        # (id(c[1]) == id(c[0])) == False
        # c[1].__eq__(c[0])
            # compare tuples element by element:
            # 0-iteration:
            my_compare_equal('x', 'x') == True
            # 1-iteration:
            my_compare_equal(np.arange(3), np.arange(3))
                # (id(np.arange(3)) == id(np.arange(3))) == False
                # np.arange(3).__eq__(np.arange(3))
                # --> np.ndarray([True, True, True])
            bool(np.ndarray([True, True, True]))
                # np.ndarray([True, True, True]).__bool__()
                    raise ValueError("The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()")

c[2] in c
# explain:
my_in(obj=c[2], container=c)
    # for loop:

    # 0-iteration:
    # elem = c[0]
    my_compare_equal(obj=c[2], elem=c[0])
        # (id(c[2]) == id(c[0])) == False
        # c[2].__eq__(c[0])
            # compare tuples element by element:
            # 0-iteration:
            my_compare_equal('y', 'x') == False
            # --> False
        # --> False

    # 1-iteration:
    # analogiusly as 0-iteration:
    my_compare_equal(obj=c[2], elem=c[1])
        # --> False
    
    # 2-iteration:
    my_compare_equal(obj=c[2], elem=c[2])
        # (id(c[2]) == id(c[2])) == True
        # --> True
    # --> True