Python生成器高级应用 - 管道模式、协程与send方法详解

def echo_generator():
    """最简单的接收值的生成器"""
    while True:
        value = yield  # yield接收send发送的值
        print(f"收到: {value}")

# 使用
gen = echo_generator()
next(gen)           # 启动生成器（必须先执行到第一个yield）
gen.send("Hello")   # 收到: Hello
gen.send("World")   # 收到: World
gen.send(42)        # 收到: 42

def counter_with_input():
    """生成器同时产出值和接收控制信号"""
    count = 0
    while True:
        increment = yield count  # 产出count，接收increment
        if increment is not None:
            count += increment
        else:
            count += 1

gen = counter_with_input()
print(next(gen))       # 0 (启动)
print(gen.send(5))     # 5 (count += 5)
print(gen.send(3))     # 8 (count += 3)
print(next(gen))       # 9 (increment为None，count += 1)

def coroutine(func):
    """自动启动协程的装饰器"""
    def wrapper(*args, **kwargs):
        gen = func(*args, **kwargs)
        next(gen)  # 自动启动
        return gen
    return wrapper

@coroutine
def grep(pattern):
    """简单的grep协程"""
    print(f"搜索模式: {pattern}")
    while True:
        line = yield  # 接收输入
        if pattern in line:
            print(f"匹配: {line}")

# 使用时无需手动next()
g = grep("python")
g.send("I love python programming")  # 匹配: I love python programming
g.send("Java is great too")          # 无输出
g.send("python is easy")             # 匹配: python is easy
g.close()  # 关闭协程

def producer(n):
    """生产者：生成1到n的整数"""
    for i in range(1, n + 1):
        yield i

def squarer(source):
    """过滤器：对每个元素求平方"""
    for item in source:
        yield item ** 2

def filter_positive(source):
    """过滤器：只保留大于10的数"""
    for item in source:
        if item > 10:
            yield item

def printer():
    """消费者：打印结果"""
    while True:
        item = yield
        print(f"结果: {item}")

# 构建管道
data = producer(10)
squared = squarer(data)
filtered = filter_positive(squared)

# 消费管道输出
for result in filtered:
    print(f"结果: {result}")
# 结果: 16
# 结果: 25
# 结果: 36
# 结果: 49
# 结果: 64
# 结果: 81
# 结果: 100

import re

@coroutine
def log_parser():
    """日志解析协程"""
    pattern = r"(\d{4}-\d{2}-\d{2}) \[(\w+)\] (.+)"
    while True:
        line = yield
        match = re.match(pattern, line)
        if match:
            date, level, message = match.groups()
            print(f"日期: {date} | 级别: {level} | 内容: {message}")

@coroutine
def log_filter(target, level):
    """日志过滤协程，只处理指定级别"""
    while True:
        line = yield
        if f"[{level}]" in line:
            target.send(line)

# 使用
parser = log_parser()
error_parser = log_filter(parser, "ERROR")

error_parser.send("2024-01-15 [INFO] Server started")
error_parser.send("2024-01-15 [ERROR] Connection timeout")
# 日期: 2024-01-15 | 级别: ERROR | 内容: Connection timeout
error_parser.send("2024-01-15 [ERROR] Disk full")
# 日期: 2024-01-15 | 级别: ERROR | 内容: Disk full

def resilient_processor():
    """能处理异常的生成器"""
    while True:
        try:
            value = yield
            print(f"处理: {value}")
        except ValueError as e:
            print(f"值错误: {e}，继续处理...")
        except TypeError as e:
            print(f"类型错误: {e}，终止处理")
            break  # 遇到TypeError则退出

gen = resilient_processor()
next(gen)

gen.send("hello")        # 处理: hello
gen.throw(ValueError, "无效的值")  # 值错误: 无效的值，继续处理...
gen.send("world")        # 处理: world
gen.throw(TypeError, "类型不匹配")  # 类型错误: 类型不匹配，终止处理

def resource_manager():
    """管理资源的生成器"""
    try:
        print("打开资源...")
        while True:
            data = yield
            print(f"使用资源处理: {data}")
    except GeneratorExit:
        print("关闭资源...清理完成!")

gen = resource_manager()
next(gen)  # 打开资源...
gen.send("数据1")  # 使用资源处理: 数据1
gen.send("数据2")  # 使用资源处理: 数据2
gen.close()  # 关闭资源...清理完成!