如何从Popen stdout获取输出类型

import subprocess

# 启动一个子进程，并将其 stdout 设置为 PIPE
process = subprocess.Popen(['ls', '-l'], stdout=subprocess.PIPE)

# 从子进程的 stdout 中读取数据
output, _ = process.communicate()

# 输出结果
print(output.decode('utf-8'))

import subprocess

process = subprocess.Popen(['ls', '-l'], stdout=subprocess.PIPE)

while True:
    output = process.stdout.readline()
    if output == b'' and process.poll() is not None:
        break
    if output:
        print(output.decode('utf-8').strip())

rc = process.poll()

import subprocess
import threading

def read_output(pipe):
    for line in iter(pipe.readline, b''):
        print(line.decode('utf-8').strip())
    pipe.close()

process = subprocess.Popen(['ls', '-l'], stdout=subprocess.PIPE)
thread = threading.Thread(target=read_output, args=(process.stdout,))
thread.start()
thread.join()