在执行 Python 文件时，如何打印该文件的 docstring？

我有一个带有 docstring 的 Python 脚本。当命令行参数的解析不成功时，我想打印用户信息的 docstring。

有什么办法吗？

最小的例子

#!/usr/bin/env python
"""
Usage: script.py


This describes the script.
"""


import sys




if len(sys.argv) < 2:
print("<here comes the docstring>")
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最佳答案

The docstring is stored in the module's __doc__ global.

print(__doc__)

By the way, this goes for any module: import sys; print(sys.__doc__). Docstrings of functions and classes are also in their __doc__ attribute.

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Here is an alternative that does not hardcode the script's filename, but instead uses sys.argv[0] to print it. Using %(scriptName)s instead of %s improves readability of the code.

#!/usr/bin/env python
"""
Usage: %(scriptName)s


This describes the script.
"""


import sys
if len(sys.argv) < 2:
print __doc__ % {'scriptName' : sys.argv[0].split("/")[-1]}
sys.exit(0)
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Argument parsing should always be done with argparse.

You can display the __doc__ string by passing it to the description parameter of Argparse:

#!/usr/bin/env python
"""
This describes the script.
"""




if __name__ == '__main__':
from argparse import ArgumentParser
parser = ArgumentParser(description=__doc__)
# Add your arguments here
parser.add_argument("-f", "--file", dest="myFilenameVariable",
required=True,
help="write report to FILE", metavar="FILE")
args = parser.parse_args()
print(args.myFilenameVariable)

If you call this mysuperscript.py and execute it you get:

$ ./mysuperscript.py --help
usage: mysuperscript.py [-h] -f FILE


This describes the script.


optional arguments:
-h, --help            show this help message and exit
-f FILE, --file FILE  write report to FILE
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This will print the __doc__ string when --help is the only argument.

if __name__=='__main__':
if len(sys.argv)==2 and sys.argv[1]=='--help':
print(__doc__)

Works for both:

  • ./yourscriptname.py --help
  • python3 yourscriptname.py --help
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An enhancement of @MartinThoma's answer so it prints multi-line docstrings inspired by Python argparse: How to insert newline in the help text?.

Argument parsing should always be done with argparse.

You can display the doc string by passing it to the description parameter of Argparse:

#!/usr/bin/env python
"""
This summarizes the script.


Additional descriptive paragraph(s).
"""  # Edited this docstring




if __name__ == '__main__':
from argparse import ArgumentParser, RawTextHelpFormatter  # Edited this line
parser = ArgumentParser(description=__doc__
formatter_class=RawTextHelpFormatter)  # Added this line
# Add your arguments here
parser.add_argument("-f", "--file", dest="myFilenameVariable",
required=True,
help="write report to FILE", metavar="FILE")
args = parser.parse_args()
print(args.myFilenameVariable)

If you call this mysuperscript.py and execute it you get:

$ ./mysuperscript.py --help
usage: mysuperscript.py [-h] -f FILE


This summarizes the script.


Additional descriptive paragraph(s).


optional arguments:
-h, --help            show this help message and exit
-f FILE, --file FILE  write report to FILE

Without the addition of the formatter_class the output would not have the line break in the docstring.


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