三元表达式 ，列表推导式 ， 字典生成式

一、三元表达式

条件成立时的返回值 if 条件 else 条件不成立时的返回值

x = 10
y = 20

print(f"x if x > y else y: {x if x > y else y}")

x if x > y else y: 20

二、列表推导式

[expression for item1 in iterable1 if condition1
for item2 in iterable2 if condition2
...
for itemN in iterableN if conditionN
]
类似于
res=[]
for item1 in iterable1:
    if condition1:
        for item2 in iterable2:
            if condition2
                ...
                for itemN in iterableN:
                    if conditionN:
                        res.append(expression)

print(F"[i for i in range(10)]: {[i for i in range(10)]}")

[i for i in range(10)]: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

print(F"[i**2 for i in range(10)]: {[i**2 for i in range(10)]}")

[i**2 for i in range(10)]: [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

三、字典生成式

print({i: i**2 for i in range(10)})

{0: 0, 1: 1, 2: 4, 3: 9, 4: 16, 5: 25, 6: 36, 7: 49, 8: 64, 9: 81}

二、zip()方法

keys = ['name', 'age', 'gender']
values = ['nick', 19, 'male']

res = zip(keys, values)
print(F"zip(keys,values): {zip(keys,values)}")

info_dict = {k: v for k, v in res}
print(f"info_dict: {info_dict}")

zip(keys,values): <zip object at 0x11074c088>
info_dict: {'name': 'nick', 'age': 19, 'sex': 'male'}

通过解压缩函数生成一个字典

info_dict = {'name': 'nick', 'age': 19, 'gender': 'male'}
print(f"info_dict.keys(): {info_dict.keys()}")
print(f"info_dict.values(): {info_dict.values()}")

res = zip(info_dict.keys(), info_dict.values())
print(F"zip(keys,values): {zip(info_dict.keys(),info_dict.values())}")

info_dict = {k: v for k, v in res}
print(f"info_dict: {info_dict}")

info_dict.keys(): dict_keys(['name', 'age', 'gender'])
info_dict.values(): dict_values(['nick', 19, 'male'])
zip(keys,values): <zip object at 0x1105cefc8>
info_dict: {'name': 'nick', 'age': 19, 'gender': 'male'}