当将 Python 的 os.popen() 函数与产生连续输出的工具一起使用时，尝试读取输出时程序经常挂起。
有问题的行进程 = os.popen("top").readlines() 由于以下原因暂停程序readlines()，它尝试一次读取整个进程的输出。
要解决此问题，请使用 subprocess.Popen() 而不是 os.popen ()。这是一个更正的示例：
<code class="python">import subprocess
import time
import os
# Start "top" process with stdout redirection
process = subprocess.Popen(["top"], stdout=subprocess.PIPE)
# Wait for 2 seconds
time.sleep(2)
# Send kill signal to "top" process
os.popen("killall top")
# Read process output
output, _ = process.communicate()
print(output.decode())</code>此修改后的代码：
如果只需要进程输出的一部分，可以使用类似尾部的解决方案来捕获特定数量的行。
捕获进程在单独的线程中输出，请尝试以下操作：
<code class="python">import collections
import subprocess
import threading
# Start process with stdout redirection
process = subprocess.Popen(["top"], stdout=subprocess.PIPE)
# Define function to read process output in a thread
def read_output(process):
for line in iter(process.stdout.readline, ""):
... # Implement your logic here to process each line
# Create and start a thread for reading and processing output
reading_thread = threading.Thread(target=read_output, args=(process,))
reading_thread.start()
# Wait for 2 seconds, then terminate the process
time.sleep(2)
process.terminate()
# Wait for the reading thread to complete
reading_thread.join()</code>您还可以使用 signal.alarm() 在指定超时后终止进程：
<code class="python">import collections
import signal
import subprocess
# Define signal handler
def alarm_handler(signum, frame):
# Raise an exception to terminate the process reading
raise Exception
# Set signal handler and alarm for 2 seconds
signal.signal(signal.SIGALRM, alarm_handler)
signal.alarm(2)
# Start process with stdout redirection
process = subprocess.Popen(["top"], stdout=subprocess.PIPE)
# Capture process output
number_of_lines = 200
q = collections.deque(maxlen=number_of_lines)
for line in iter(process.stdout.readline, ""):
q.append(line)
# Cancel alarm
signal.alarm(0)
# Print captured output
print(''.join(q))</code>或者，您可以使用 threading.Timer 来安排进程终止：
<code class="python">import collections
import subprocess
import threading
# Define function to terminate the process
def terminate_process(process):
process.terminate()
# Start process with stdout redirection
process = subprocess.Popen(["top"], stdout=subprocess.PIPE)
# Create and start a timer to terminate process in 2 seconds
timer = threading.Timer(2, terminate_process, [process])
timer.start()
# Capture process output
number_of_lines = 200
q = collections.deque(process.stdout, maxlen=number_of_lines)
# Cancel timer
timer.cancel()
# Print captured output
print(''.join(q))</code>以上是如何避免Python程序在读取连续进程输出时挂起？的详细内容。更多信息请关注PHP中文网其他相关文章！
