Python子进程等待，直到标准输出上的特定字符串

import subprocess
import re

process = subprocess.Popen(['command'], stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True)

while True:
    output = process.stdout.readline()
    if output == '' and process.poll() is not None:
        break
    if re.search('特定字符串', output):
        break

process.communicate()

import subprocess
import re

def wait_for_string():
    process = subprocess.Popen(['command'], stdout=subprocess.PIPE, stderr=subprocess.PIPE, universal_newlines=True)
    while True:
        output = process.stdout.readline()
        if output == '' and process.poll() is not None:
            break
        if re.search('特定字符串', output):
            break
    process.communicate()

wait_for_string()