Python推导式

1. 列表推导式

# list
print("list")

list_a = [item * item for item in range(10)]
print(list_a)

list_to_string = [str(i) for i in range(10)]
print(list_to_string)

list_condition = [i for i in range(10) if i > 3]
print(list_condition)

list_condition_else = [i * i if i > 5 else str(i) for i in range(10)]
print(list_condition_else)

2. 元组推导式

• 这玩意出来是个生成器，因为元组不可变，所以只能这么返回，符合语法
• 生成器读取一遍，数据就没了

# tuple
print("\ntuple")
tuple_a_generator = (item * item for item in range(3, 5))
print(tuple_a_generator)
print(tuple(tuple_a_generator))
print(tuple(tuple_a_generator))

3. 映射推导式

# map
print("\nmap")
map_a = {item["key"]: item for item in [{'key': 1, 'name': 'a'}, {'key': 2, 'name': 'b'}, {'key': 3, 'name': 'c'}]}
print(map_a)