Python屏蔽输出信息如何用装饰器屏蔽函数的返回打印 Python屏蔽输出信息的装饰器管控教程​

import sys
import io

def silence(func):
    def wrapper(*args, **kwargs):
        # 备份标准输出
        original_stdout = sys.stdout
        # 创建一个StringIO对象来捕获输出
        sys.stdout = io.StringIO()

        try:
            result = func(*args, **kwargs)
        finally:
            # 恢复标准输出
            sys.stdout = original_stdout

        return result
    return wrapper

@silence
def my_function():
    print("This will be silenced.")
    return "Function returned something"

# 调用被装饰的函数
return_value = my_function()
print(f"Returned value: {return_value}") # 只会打印这一行

silence

sys.stdout

io.StringIO()

print

sys.stdout

silence

print

@silence
def another_function():
    return "This return value won't be printed directly"

# 屏蔽返回值打印的调用方式
_ = another_function()  # 将返回值赋给一个不使用的变量

# 或者, 如果你真的需要返回值，但不想立即打印：
return_value = another_function()
# 在需要的时候再处理返回值
print(f"Later processing: {return_value}")

import sys
import io

def conditional_silence(condition):
    def decorator(func):
        def wrapper(*args, **kwargs):
            if condition():
                original_stdout = sys.stdout
                sys.stdout = io.StringIO()
                try:
                    result = func(*args, **kwargs)
                finally:
                    sys.stdout = original_stdout
                return result
            else:
                return func(*args, **kwargs)
        return wrapper
    return decorator

# 示例：只有当DEBUG模式为True时才屏蔽输出
DEBUG = False

@conditional_silence(lambda: DEBUG)
def yet_another_function():
    print("This might be silenced, depending on DEBUG mode.")
    return "Another function returned"

return_value = yet_another_function()
print(f"Returned value: {return_value}")

DEBUG = True # 改变DEBUG模式

return_value = yet_another_function() # 输出会被屏蔽
print(f"Returned value: {return_value}")

conditional_silence

True

try...finally

finally

try

import sys
import io

def robust_silence(func):
    def wrapper(*args, **kwargs):
        original_stdout = sys.stdout
        sys.stdout = io.StringIO()
        try:
            result = func(*args, **kwargs)
            return result
        except Exception as e:
            # 记录异常信息，并恢复标准输出
            print(f"An error occurred: {e}") # 可以选择将异常信息输出到日志
            raise  # 重新抛出异常，确保异常被正确处理
        finally:
            sys.stdout = original_stdout
    return wrapper

@robust_silence
def function_that_might_fail():
    print("Trying something...")
    raise ValueError("Something went wrong")
    print("This won't be printed")

try:
    function_that_might_fail()
except ValueError as e:
    print(f"Caught the error: {e}")

robust_silence

except

sys.stdout

sys.stdout

import sys
import io
import threading

thread_local = threading.local()

def thread_safe_silence(func):
    def wrapper(*args, **kwargs):
        if not hasattr(thread_local, 'original_stdout'):
            thread_local.original_stdout = sys.stdout
            thread_local.string_io = io.StringIO()

        sys.stdout = thread_local.string_io

        try:
            result = func(*args, **kwargs)
            return result
        finally:
            sys.stdout = thread_local.original_stdout
            #可以选择在这里清空thread_local.string_io，避免内存泄漏

    return wrapper

@thread_safe_silence
def thread_function():
    print("This is from a thread.")

import threading
threads = []
for i in range(5):
    t = threading.Thread(target=thread_function)
    threads.append(t)
    t.start()

for t in threads:
    t.join()

thread_safe_silence

threading.local()

thread_local

thread_local

sys.stdout

sys.stdout

sys.stdout