字符串比较失败 [英] String comparison fails

问题描述

output = subprocess.check_output("./mount.sh", shell=True)
print output
if output == "expected_String":
      print "Hurray!"

（打印命令只是检查输出是否符合我的预期）。每次比较都会失败我不明白为什么。我用这个代替了check_output

(The print command is just to check if the output is what I expected).The comparison fails everytime and I don't get why. I tried it with this instead of check_output

(stdout, stderr) = Popen(["./mount.sh"], stdout=PIPE).communicate()
mountout = stdout

但我不认为这是这里的问题，因为

but I don't think that's the problem here because

 print output

给出了我的期望，但是如果我尝试将其与我的 expected_String进行比较，它总是错误的。

gives me what I expect but if I try to compare it to my "expected_String" it is always false.

推荐答案

我相信问题在于您的输出末尾包含其他换行符。您可以通过调用 .strip（）来删除它们：

I believe the problem is your output contains additional new line character at the end. You can fix it by calling .strip() to remove those:

output = subprocess.check_output("./mount.sh", shell=True)
output = output.strip()

更新：如何查找字符串是否以换行符结尾？

请考虑以下交互式会话：

Update: How to Find out If a String Ends with New Line?

Consider the following interactive session:

>>> s = '''hello\n'''
>>> s.endswith('\n')
True

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