python各种推导式

字典推导式

例一：将一个字典的key和value对调

mcase = {'a': , 'b': }
mcase_frequency = {mcase[k]: k for k in mcase}
print(mcase_frequency)

例二：合并大小写对应的value值，将k统一成小写

mcase = {'a': , 'b': , 'A': , 'Z': }
mcase_frequency = {k.lower(): mcase.get(k.lower(), ) + mcase.get(k.upper(), ) for k in mcase.keys()}
print(mcase_frequency

集合推导式

例：计算列表中每个值的平方，自带去重功能

squared = {x** for x in [, -, ]}
print(squared)
# Output: set([, ])

元组变字典面试题

t  =(('a','b'),('c','d'))
tup1 = t[]
tup2 = t[]

print(list(map(lambda t3:{t3[]:t3[]} ,zip(tup1,tup2))))