Python-找字典中公共key-zip reduce lambda
2024-08-27 14:19:24
场景实例:
西班牙足球联赛,每轮球员进球统计:
第一轮:{’1’:1,‘2’:4,‘5’:2,‘7’:3}
第一轮:{’2’:1,‘5’:4,‘6’:2,‘3’:3}
第一轮:{’1’:1,‘4’:4,‘6’:2,‘7’:3}
……
问题:统计前N轮,都进球的球员?
如何解决这个问题呢?
方法1:
#!/usr/bin/python3 from random import randint, sample def get_s(player):
# 获得三个赛季的随机记录
s1 = {k: randint(1, 6) for k in sample(player, randint(3, 6))}
s2 = {k: randint(1, 6) for k in sample(player, randint(3, 6))}
s3 = {k: randint(1, 6) for k in sample(player, randint(3, 6))}
return s1, s2, s3 def public_keys(s1, s2, s3):
# 定义中间列表
median = [] # 判断字典公共key,在s1,在s2,在s3肯定是公共key
for key in s1:
if key in s2 and key in s3:
median.append(key)
return median if __name__ == '__main__':
# 生成abcdef个球员
player = 'abcdef' # 获得3个赛季的随机数
s1, s2, s3 = get_s(player) # 获取3个赛季都进球的球员
result = public_keys(s1,s2,s3)
print(result)
方法2:
进球的球员都是数据中的key,通过求出每一轮的keys,然后做个交集就可以求出结果
#!/usr/bin/python3 from random import randint, sample def get_s(player):
# 获得三个赛季的随机记录
s1 = {k: randint(1, 6) for k in sample(player, randint(3, 6))}
s2 = {k: randint(1, 6) for k in sample(player, randint(3, 6))}
s3 = {k: randint(1, 6) for k in sample(player, randint(3, 6))}
return s1, s2, s3 def public_keys(s1, s2, s3):
# 返回各字典的单边值,并求出交集,即是结果
return s1.keys() & s2.keys() & s3.keys() if __name__ == '__main__':
# 生成abcdef个球员
player = 'abcdef' # 获得3个赛季的随机数
s1, s2, s3 = get_s(player) # 获取3个赛季都进球的球员
result = public_keys(s1, s2, s3)
print(result)
方法3:
当N轮时候,通过map和reduce函数
#!/usr/bin/python3 from random import randint, sample
from functools import reduce def get_s(player):
# 获得三个赛季的随机记录
s1 = {k: randint(1, 6) for k in sample(player, randint(3, 6))}
s2 = {k: randint(1, 6) for k in sample(player, randint(3, 6))}
s3 = {k: randint(1, 6) for k in sample(player, randint(3, 6))}
return s1, s2, s3 def public_keys(s1, s2, s3):
result = reduce(lambda a, b: a & b, map(dict.keys, [s1, s2, s3]))
# map(dict. keys,[s1,s2,s3,......N] 获得每轮的keys集合,s1……N为字典对象
# reduce((lamda a,b: a&b,map()) 把map获得的集合,依次放入a,b,返回交集
# a,b = a&b, map中取出的一个值map(dict.keys, [s1, s2, s3])取得新的列表
# reduce中的lambda只能传入两个参数
# map 为高阶函数,接收一个map(函数, [参数]),迭代参数列表,一个传入函数中处理,返回处理结果变成新的列表 return result if __name__ == '__main__':
# 生成abcdef个球员
player = 'abcdef' # 获得3个赛季的随机数
s1, s2, s3 = get_s(player) # 获取3个赛季都进球的球员
result = public_keys(s1, s2, s3)
print(result)
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