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  • Python的collections之defaultdict的使用及其优势

    user_dict = {}
    users = ["baoshan1", "baoshan2", "baoshan3","baoshan1", "baoshan2", "baoshan2"]
    for user in users:
        if user not in user_dict:
            user_dict[user] = 1
        else:
            user_dict[user] += 1
    print(user_dict)
    
    
    user_dict = {}
    users = ["baoshan1", "baoshan2", "baoshan3","baoshan1", "baoshan2", "baoshan2"]
    for user in users:
        user_dict.setdefault(user, 0)
        user_dict[user] += 1
    print(user_dict)
    
    
    # 不需要做if else的判断
    # 效率高,少一次user_dict的查询操作
    
    from collections import defaultdict
    user_dict = defaultdict(int)
    users = ["baoshan1", "baoshan2", "baoshan3","baoshan1", "baoshan2", "baoshan2"]
    for user in users:
        user_dict[user] += 1
    print(user_dict)
    # defaultdict的好处,传递可调用的对象例如int、list、函数等
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  • 原文地址:https://www.cnblogs.com/zhzhang/p/11244478.html
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