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Python中关于set的基本用法

目录
  • 1. set 的基本内容
    • 1.基本特点
    • 2.set() 实质
  • 2. set 的基本方法
    • 2.1 set 的普通基本方法
    • 2.2 set 的逻辑基本方法
  • 总结

    1. set 的基本内容

    1.基本特点

    • (1) 无序性
    • (2) 确定性
    • (3) 不重复性

    2.set() 实质

    内部进行 可迭代性的 for 循环

    例子:

    Python中关于set的基本用法

    2. set 的基本方法

    2.1 set 的普通基本方法

    2.1.1 增

    add(self, *args, **kwargs)
    copy(self, *args, **kwargs)
    
    # 1. 增
    
    # Add an element to a set. This has no effect if the element is already present.
    s = {1, 12, 32, "涟漪", "hello"}
    s.add("good")
    s.add(32)
    print(s)
    
    # Add an element to a set. This has no effect if the element is already present.
    s = {1, 12, 32, "涟漪", "hello"}
    c = s.copy()
    print(c)
    

    结果:

    Python中关于set的基本用法

    2.1.1 删

    clear(self, *args, **kwargs)
    pop(self, *args, **kwargs)
    remove(self, *args, **kwargs)
    discard(self, *args, **kwargs)
    
    # 2. 删
    
    # Remove all elements from this set.
    s = {1, 12, 32, "涟漪", "hello"}
    s.clear()
    print(s)
    
    # Remove and return an arbitrary set element. Raises KeyError if the set is empty.
    s = {1, 12, 32, "涟漪", "hello"}
    s.pop()
    print(s)
    
    # Remove an element from a set; it must be a member. If the element is not a member, raise a KeyError.
    s = {1, 12, 32, "涟漪", "hello"}
    s.remove(1)
    # s.remove("good")
    print(s)
    
    # Remove an element from a set if it is a member. If the element is not a member, do nothing.
    s = {1, 12, 32, "涟漪", "hello"}
    s.discard(1)
    s.discard("good")
    print(s)
    

    结果:

    Python中关于set的基本用法

    pop() 是随机删除。

    remove() 和 discard() 指定删除,但是指定不存在的元素时,remove() 会报错,而 discard() 不会报错

    2.2 set 的逻辑基本方法

    2.2.1 set 交集运算

    # set 交集运算
    x1 = ["a", "b", "c", "d", "e"]
    x2 = ["cDquKVKzGHA", "djavascript", "e", "f", "g"]
    x3 = []
    for x in x1:
        if x in x2:
            x3.appepythonnd(x)
    print(x3)
    
    s_x1 = set(x1)
    s_x2 = set(x2)
    inter = s_x1.intersection(s_x2)
    print(inter)
    # 交集符号运算
    print(s_x1 & s_x2)
    # update
    s_x1.intersection_update(s_x2)
    print(s_x1)
    

    结果:

    Python中关于set的基本用法

    2.2.2 set 并集运算

    # set 并集运算
    x1 = ["a", 编程客栈"b", "c", "d", "e"开发者_JAVA教程]
    x2 = ["c", "d", "e", "f", "g"]
    s_x1 = set(x1)
    s_x2 = set(x2)
    uni = s_x1.union(s_x2)
    print(uni)
    # 并集符号运算
    print(s_x1 | s_x2)
    # update
    s_x1.update(s_x2)
    print(s_x1)
    

    结果:

    Python中关于set的基本用法

    2.2.3 set 差集运算

    # set 差集运算
    x1 = ["a", "b", "c", "d", "e"]
    x2 = ["c", "d", "e", "f", "g"]
    s_x1 = set(x1)
    s_x2 = set(x2)
    dif_x1 = s_x1.difference(s_x2)
    print(dif_x1)
    dif_x2 = s_x2.difference(s_x1)
    print(dif_x2)
    # 差集符号运算
    print(s_x1 - s_x2)
    print(s_x2 - s_x1)
    # update
    s_x1.difference_update(s_x2)
    print(s_x1)
    s_x2.difference_update(s_x1)
    print(s_x2)
    

    结果:

    Python中关于set的基本用法

    2.2.4 set 对称差集运算

    # set 对称差集运算满足交换律:A△B = B△A
    s_x1 = set(x1)
    s_x2 = set(x2)
    sym = s_x1.symmetric_difference(s_x2)
    print(sym)
    # 对称差集符号运算
    print(s_x1 ^ s_x2)
    print(s_x1 - s_x2 | s_x2 - s_x1)
    print((s_x1 | s_x2) - (s_x2 & s_x1))
    # update
    s_x1.symmetric_difference_update(s_x2)
    print(s_x1)
    

    结果:

    Python中关于set的基本用法

    2.2.5 set 逻辑判断运算

    # 判断
    # Return True if two sets have a null intersection.
    x1 = {"a", "b", "c"}
    x2 = {"e", "f", "g"}
    inter = x1.isdisjoint(x2)
    print(inter)
    
    # Report whether another set contains this set.
    x1 = {"a", "b", "c"}
    x2 = {"a", "b", "c", "e", "f", "g"}
    inter = x1.issubset(x2)
    print(inter)
    
    # Report whether this set contains another set.
    x1 = {"a", "b", "c", "e", "f", "g"}
    x2 = {"a", "b", "c"}
    inter = x1.issuperset(x2)
    print(intejsr)
    

    结果:

    Python中关于set的基本用法

    总结

    以上为个人经验,希望能给大家一个参考,也希望大家多多支持我们。

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