employee_new = [{
'Name': employee['Name'],
'Salary': employee['Salary'] + 200
} if employee['Salary'] > 150 else {
'Name': employee['Name'],
'Salary': employee['Salary'] + 500
} for employee in employee_old]
"""
# employees_new = [
# {'name': employee['name'], 'salary': employee['salary'] + 200} if employee['salary'] > 5000 else
# {'name': employee['name'], 'salary': employee['salary'] + 500} for employee in employee_old]
"""
#print(employees_new)
print(employee_new)
print_info("字典推导式")
dict_old = {'a': 'A', 'b': 'B', 'c': 'C', 'd': 'D'}
dict_new = {value: key for key, value in dict_old.items()}
print(dict_new)
print_info("集合推导式:典型用法 -- 去重")
list_old = [1, 2, 3, 5, 2, 3]
set_new = {x for x in list_old}
print(set_new)
print_info("生成器")
my_generator = (x for x in range(5)) # 注意是()
print(my_generator)
print(type(my_generator))
print('a')
print(my_generator.__next__())
from tools.print_info import print_info
def say(func):
def wrapper(*args, **kwargs):
func(*args, **kwargs)
return wrapper
@say
def greet(name):
print("Hello {}".format(name))
print_info("丢失原始函数信息")
print(greet.__name__)
print_info("想要不丢失原始函数信息可以用@functools.wrapper")
import functools
import time
def timer(func):
@functools.wraps(func)
def wrapper(*args, **kwargs):
start_time = time.perf_counter()
value = func(*args, **kwargs)
end_time = time.perf_counter()
run_time = end_time - start_time
from tools.print_info import print_info
print_info('*args和**kwargs 接收参数')
def say(func):
def wrapper(*args, **kwargs):
func(*args, **kwargs)
return wrapper
@say
def greet(name):
print("Hello {}".format(name))
greet("xiaojing")
print(greet.__name__)
from tools.print_info import print_info
print_info('装饰器嵌套')
def hello(func):
def wrapper():
print("Hello")
func()
return wrapper
def welcome(func):
def wrapper():
print('Welcome')
func()
return wrapper
def say():
print('Good')
say = hello(welcome(say))
say()
print_info("使用语法糖")
from tools import print_info as info
info.print_info("手动实现装饰器")
def my_decorator(my_func):
def my_wrapper():
print('Before the function runs')
my_func()
print('After the function runs')
return my_wrapper
def my_func():
print('I am a stand alone function, don\'t you dare modify me')
# my_func()
my_func_decorator = my_decorator(my_func)
my_func_decorator()
info.print_info("语法糖")
# 使用语法糖
@my_decorator
def my_another_func():
print('Leave me alone')
import functools
import time
from tools.print_info import print_info
print_info("装饰方法")
def timer(func):
@functools.wraps(func)
def wrapper(*args, **kwargs):
start_time = time.perf_counter()
value = func(*args, **kwargs)
end_time = time.perf_counter()
run_time = end_time - start_time
# print(func.__name__)
# print(run_time)
print("Finished {} in {} s".format(repr(func.__name__),
round(run_time, 3)))
return value
return wrapper
class Calculator:
def __init__(self, num):
self.num = num
@timer
def doubled_and_add(self):
res = sum([i * 2 for i in range(self.num)])
print("Result : {}".format(res))