if __name__ == "__main__": parser = argparse.ArgumentParser( formatter_class=argparse.ArgumentDefaultsHelpFormatter) parser.add_argument("--host", default="127.0.0.1", required=False, help="host") parser.add_argument("--port", default=8091, required=False, help="port") args = parser.parse_args() # 127.0.0.1本机调用,端口为8091 app.run(host=args.host, port=int(args.port), debug=False, use_reloader=False)详细讲解一下这段代码
时间: 2023-06-08 17:08:06 浏览: 70
如果__name__等于“__main__”,则会创建一个命令行参数解析器parser,并使用argparse.ArgumentDefaultsHelpFormatter格式进行设置。然后解析器指定了两个可选参数“--host”和“--port”,并设置了它们的默认值、帮助文本和是否必须指定的选项。最后,使用parse_args()方法解析命令行参数并将其存储在args对象中。
相关问题
def get_argparser(): parser = argparse.ArgumentParser()
Sorry, as an AI language model, I don't have access to the previous context or the purpose of the function you shared. But based on the function signature, it seems like this is a Python function that returns an instance of the `ArgumentParser` class from the `argparse` module. The purpose of this class is to create a parser object that can parse command-line arguments and options.
Here's an example usage of the `ArgumentParser` class:
```
import argparse
def get_argparser():
parser = argparse.ArgumentParser()
parser.add_argument('--name', help='Enter your name')
parser.add_argument('--age', type=int, help='Enter your age')
return parser
if __name__ == '__main__':
parser = get_argparser()
args = parser.parse_args()
print(f"Hello {args.name}, you are {args.age} years old!")
```
In the above example, the `get_argparser()` function creates an instance of the `ArgumentParser` class and adds two arguments to it - `name` and `age`. The `parse_args()` method of the parser object is then called to parse the command-line arguments and options. Finally, the values of the `name` and `age` arguments are printed using the `print()` function.
formatter_class=argparse.ArgumentDefaultsHelpFormatter
The `formatter_class=argparse.ArgumentDefaultsHelpFormatter` is an argument formatter that can be used with the `ArgumentParser` class in Python's `argparse` module.
When this formatter class is used, the help message generated by the `ArgumentParser` object will include default values for each argument, along with any help text that was provided. This can be useful for helping users understand what the default behavior of the program is and how to modify it if necessary.
For example, if you have an argument defined like this:
```python
parser.add_argument('--threshold', default=0.5, type=float, help='threshold value for filtering')
```
By default, the help message generated by `ArgumentParser` would look something like this:
```
usage: my_program.py [-h] [--threshold THRESHOLD]
optional arguments:
-h, --help show this help message and exit
--threshold THRESHOLD
threshold value for filtering
```
However, if you use the `ArgumentDefaultsHelpFormatter`, the help message would look like this:
```
usage: my_program.py [-h] [--threshold THRESHOLD]
optional arguments:
-h, --help show this help message and exit
--threshold THRESHOLD
threshold value for filtering (default: 0.5)
```
Note the `(default: 0.5)` added to the end of the help text for the `--threshold` argument. This helps users understand that the default threshold value is 0.5, which they can change if necessary.