python字典个数统计 python字典统计人数

字典的合并

班级学籍信息统计如下：女生籍贯分布是江苏3人，浙江2人，吉林1人；男生籍贯分布是江苏8人，浙江5人，山东5人，安徽4人，福建2人。编写程序将统计结果合并并输出。

male = {"江苏": 8, "浙江": 5, "山东": 5, "安徽": 4, "福建": 2}
female = {"江苏": 3, "浙江": 2, "吉林": 1}
dic = male.copy() //复制其中的一个空表
for k, v in female.items():
    dic[k] = dic.get(k, 0) + v
print(dic)

Python 字典get() 函数返回指定键的值，如果值不在字典中返回默认值。

dict.get(key, default=None)

字典的统计与查找

学生基本信息如表所示。请分别统计男、女生人数，并查找所有年龄超过18岁学生的姓名。

dictStudent = {"黎明": ["男", 19], "杨柳": ["女", 18], "张一帆": ["男", 18], "许可": ["女", 20], "王笑笑": ["女", 19], "陈欣": ["女", 19]}
count = {}
names = []
for k, v in dictStudent.items():
    count[v[0]] = count.get(v[0], 0) + 1
    if v[1] > 18:
        names.append(k)
print("男女生人数为"+str(count))
print("年龄超过18岁的学生姓名为"+str(names))

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例二:

班级对“双十一”期间学生消费进行了匿名调查，结果如表所示。编写程序，1、统计每一类消费项目的平均消费金额；2、分别统计男生、女生“双十一”期间消费总额的平均值。

lstExpenses = [{"性别": "女", "书本": 10, "文具": 30, "服饰": 300, "零食": 150, "日用品": 600},
               {"性别": "女", "书本": 200, "文具": 10, "服饰": 300, "零食": 300, "日用品": 100},
               {"性别": "男", "书本": 200, "文具": 100, "服饰": 100, "零食": 100, "日用品": 200},
               {"性别": "男", "书本": 50, "文具": 20, "服饰": 300, "零食": 100, "日用品": 200},
               {"性别": "男", "书本": 200, "文具": 50, "服饰": 400, "零食": 100, "日用品": 200},
               {"性别": "女", "书本": 100, "文具": 10, "服饰": 5300, "零食": 150, "日用品": 800},
               {"性别": "女", "书本": 200, "文具": 100, "服饰": 500, "零食": 300, "日用品": 200},
               {"性别": "男", "书本": 300, "文具": 50, "服饰": 0, "零食": 10, "日用品": 50},
               {"性别": "男", "书本": 100, "文具": 10, "服饰": 500, "零食": 40, "日用品": 500},
               {"性别": "男", "书本": 200, "文具": 50, "服饰": 200, "零食": 100, "日用品": 100}
               ]
dicTotal = {}
for dic in lstExpenses:
    for k, v in dic.items():
        if k != "性别":
            dicTotal[k] = dicTotal.get(k, 0) + v
for k, v in dicTotal.items():
    print("{}:{:.2f}".format(k, v / len(lstExpenses)), )  # 统计各类产品的平均消费额

dicAVG = {}
dicCnt = {}
for dic in lstExpenses:
    s = 0
    for k, v in dic.items():
        if k != "性别":
            s = s + v # 计算每一行的消费总额
    dicAVG[dic["性别"]]  = dicAVG.get(dic["性别"],0)+s # 把相应的总额加到 各类性别中去
    dicCnt[dic["性别"]]  = dicCnt.get(dic["性别"],0)+1 # 统计男女数量
for sex in ("男","女"):
    dicAVG[sex] = dicAVG[sex]/dicCnt[sex]
print(dicAVG)