python Python字符串比较
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/2516787/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Python string comparison
提问by ravun
I have a python function that makes a subprocess call to a shell script that outputs 'true' or 'false'. I'm storing the output from subprocess.communicate()and trying to do return output == 'true'but it returns Falseevery time. I'm not too familiar with python, but reading about string comparisons says you can compare strings using ==, !=, etc.
我有一个 python 函数，它对输出“true”或“false”的 shell 脚本进行子进程调用。我正在存储来自subprocess.communicate()并尝试执行的输出，return output == 'true'但它False每次都会返回。我对 python 不太熟悉，但是阅读有关字符串比较的内容时说您可以使用 ==、!= 等来比较字符串。
Here's the code:
这是代码：
def verifydeployment(application):
from subprocess import Popen, PIPE
import socket, time
# Loop until jboss is up. After 90 seconds the script stops looping; this
# causes twiddle to be unsuccessful and deployment is considered 'failed'.
begin = time.time()
while True:
try:
socket.create_connection(('localhost', 8080))
break
except socket.error, msg:
if (time.time() - begin) > 90:
break
else:
continue
time.sleep(15) # sleep for 15 seconds to allow JMX to initialize
twiddle = os.path.join(JBOSS_DIR, 'bin', 'twiddle.sh')
url = 'file:' + os.path.join(JBOSS_DIR, 'server', 'default', 'deploy', os.path.basename(application))
p = Popen([twiddle, 'invoke', 'jboss.system:service=MainDeployer', 'isDeployed', url], stdout=PIPE)
isdeployed = p.communicate()[0]
print type(isdeployed)
print type('true')
print isdeployed
return isdeployed == 'true'
The output is:
输出是：
<type 'str'> # type(isdeployed)
<type 'str'> # type('true')
true # isdeployed
but Falseis always returned. I also tried return str(isdeployed) == 'true'.
但False总是返回。我也试过了return str(isdeployed) == 'true'。
回答by unwind
Are you sure that there isn't a terminating line feed character, making your string contain "true\n"? That seems likely.
您确定没有终止换行符，使您的字符串包含"true\n"? 这似乎很有可能。
You could try return isdeployed.startswith("true"), or some stripping.
您可以尝试 returnisdeployed.startswith("true")或一些剥离。
回答by Tuomas Pelkonen
Have you tried to call
你有没有试过打电话
isdeployed.strip()
before the comparision
对比前
