Python 字典
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Python 字典
1. 遍历字典
- 遍历字典的键
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dict1 = {‘a‘: 1, ‘b‘: 2, ‘c‘: 3, ‘d‘: 4} for key in dict1.keys(): print(key) # 输出:a b c d
- 遍历字典的值
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dict1 = {‘a‘: 1, ‘b‘: 2, ‘c‘: 3, ‘d‘: 4} for value in dict1.values(): print(value) dict1.get(‘a‘) dict1.get(‘b‘) dict1.get(‘c‘) # 输出:1 2 3 4
- 遍历字典的键值对
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dict1 = {‘a‘: 1, ‘b‘: 2, ‘c‘: 3, ‘d‘: 4} for k, v in dict1.items(): print(k, ": ", v) # 输出: a : 1 b : 2 c : 3 d : 4
- 更新字典
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dict1 = {‘a‘: 1, ‘b‘: 2, ‘c‘: 3, ‘d‘: 4} dict2 = {‘e‘: 5} dict1.update(dict2) print(dict1) # 输出:{‘a‘: 1, ‘b‘: 2, ‘c‘: 3, ‘d‘: 4, ‘e‘: 5}
- 删除字典所有键值对
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dict1 = {‘a‘: 1, ‘b‘: 2, ‘c‘: 3, ‘d‘: 4, ‘e‘: 5} dict1.clear() print(dict1) # 输出:{}
- 删除最后一个键值对
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dict1 = {‘a‘: 1, ‘b‘: 2, ‘c‘: 3, ‘d‘: 4, ‘e‘: 5} dict1.popitem() print(dict1) # 输出:{‘a‘: 1, ‘b‘: 2, ‘c‘: 3, ‘d‘: 4}
- 比较两个字典的差异
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dict1 = {‘a‘: 1, ‘b‘: 2, ‘c‘: 3, ‘d‘: 4} dict2 = {‘a‘: 1, ‘b‘: 2, ‘c‘: 5, ‘e‘: 6} differ = set(dict1.items()) ^ set(dict2.items()) """输出所有的差异""" print(differ) # 输出:{(‘c‘, 3), (‘e‘, 6), (‘c‘, 5), (‘d‘, 4)} """获取两个字典key的交集""" diff = dict1.keys() & dict2 print(diff) # 输出:{‘a‘, ‘c‘, ‘b‘} """输出相同key下的不同value""" diff_vals = [(k, dict1[k], dict2[k]) for k in diff if dict1[k] != dict2[k]] print(diff_vals) # 输出:[(‘c‘, 3, 5)]
- 直接赋值何copy的区别
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