Python中元素列表操作的重载算术和比较运算符

Question

我有一堂课：

class Data:
    def __init__(self, data: dict):
        self.data = data
    
    

我想执行诸如

d = {'a': [1, 2, 3], 'b':[4, 5, 6]}
objA = Data(d)
objA.data['a'] + 2               # this should return element-wise addition=> [3, 4, 5]
objA.data['a'] + objA.data['b']  # this should return element-wise addition=> [5, 7, 9]
objA.data['a'] > 2               # this should return element-wise comparison=> [False, False, True]

如何重载算术和比较运算符以执行列表的元素操作？

Answer 1

你可以使用这个：

class MathList:
    def __init__(self, data: list):
        self.data = data
    
    def __add__(self, n):
        return [x + n for x in self.data]

    def __sub__(self, n):
        return [x - n for x in self.data]

    def __mul__(self, n):
        return [x * n for x in self.data]

    def __truediv__(self, n):
        return [x / n for x in self.data]

    def __eq__(self, n):
        return [x == n for x in self.data]

    def __ne__(self, n):
        return [x != n for x in self.data]

    def __lt__(self, n):
        return [x < n for x in self.data]

    def __le__(self, n):
        return [x <= n for x in self.data]

    def __gt__(self, n):
        return [x > n for x in self.data]

    def __ge__(self, n):
        return [x >= n for x in self.data]


class Data:
    def __init__(self, data: dict):
        self.data = {k: MathList(v) for k, v in data.items()}

d = Data({
    'a': [1, 2, 3],
    'b': [4, 5, 6]
})

# Arithmatic operations
print(d.data['a'] + 2)  # Output: [3, 4, 5]
print(d.data['b'] - 2)  # Output: [2, 3, 4]
print(d.data['a'] * 2)  # Output: [2, 4, 6]
print(d.data['b'] / 2)  # Output: [2.0, 2.5, 3.5]

# Boolean operations
print(d.data['a'] == 2) # Output: [False, True, False]
print(d.data['b'] != 4) # Output: [False, True, True]
print(d.data['a'] < 3)  # Output: [True, True, False]
print(d.data['b'] <= 4) # Output: [True, False, False]
print(d.data['a'] > 2)  # Output: [False, False, True]
print(d.data['b'] >= 5) # Output: [False, True, True]

这会创建一个名为MathList的新类，它会执行您想要的操作

编辑：你可能想看看 numpy，也可以这样做

Answer 2

我已将data定义为list

class Data:
    def __init__(self, data: list):
        self.data = data

    def __add__(self, x):
        self.data.append(x)
        return self

    def __sub__(self, x):
        self.data.remove(x)
        return self

    def __lt__(self, x):
        return [item < x for item in self.data]

    def __le__(self, x):
        return [item <= x for item in self.data]

    def __eq__(self, x):
        return [item == x for item in self.data]

    def __ne__(self, x):
        return [item != x for item in self.data]

    def __gt__(self, x):
        return [item > x for item in self.data]

    def __ge__(self, x):
        return [item >= x for item in self.data]

    def __repr__(self):
        return str(self.data)


objA = Data([1, 2, 3])
objB = Data([4, 5, 6])
objA = objA + 7
print(objA)  # Output: [1, 2, 3, 7]
objA = objA - 7
print(objA)  # Output: [1, 2, 3]
print(objA < 2)  # Output: [True, False, False]
print(objA <= 2)  # Output: [True, True, False]
print(objA == 2)  # Output: [False, True, False]
print(objA != 2)  # Output: [True, False, True]
print(objA < 2)  # Output: [True, False, False]
print(objA >= 2)  # Output: [False, True, True]