Yes, you can set the `help` option to `add_argument` to `argparse.SUPPRESS`. Here&#39;s an example from the [argparse documentation][1]:

    &gt;&gt;&gt; parser = argparse.ArgumentParser(prog=&#39;frobble&#39;)
    &gt;&gt;&gt; parser.add_argument(&#39;--foo&#39;, help=argparse.SUPPRESS)
    &gt;&gt;&gt; parser.print_help()
    usage: frobble [-h]

    optional arguments:
      -h, --help  show this help message and exit


  [1]: http://docs.python.org/dev/library/argparse.html#help

I do it by adding an option to enable the hidden ones, and grab that by looking at `sysv.args`. 

If you do this, you have to include the special arg you pick out of `sys.argv` directly in the parse list if you Assume the option is `-s` to enable hidden options.
    
    parser.add_argument(&#39;-a&#39;, &#39;-axis&#39;,
                        dest=&quot;axis&quot;, action=&quot;store_true&quot;, default=False,
                        help=&quot;Rotate the earth&quot;)
    if &quot;-s&quot; in sys.argv or &quot;-secret&quot; in sys.argv:
        parser.add_argument(&#39;-s&#39;, &#39;-secret&#39;,
                            dest=&quot;secret&quot;, action=&quot;store_true&quot;, default=False,
                            help=&quot;Enable secret options&quot;)
        parser.add_argument(&#39;-d&#39;, &#39;-drill&#39;,
                            dest=&quot;drill&quot;, action=&quot;store_true&quot;, default=False,
                            help=&quot;drill baby, drill&quot;)

Why in Java you&#39;re able to add Strings with the + operator, when String is a class?  In the`String.java` code I did not find any implementation for this operator. Does this concept violate object orientation?

How does the String class override the + operator?

Is there a function that can truncate or round a Double?  At one point in my code I would like a number like: `1.23456789` to be rounded to `1.23`

Scala Doubles, and Precision

Is it possible to add an Argument to an python [`argparse.ArgumentParser`][1] without it showing up in the usage or help (`script.py --help`)?


  [1]: http://docs.python.org/library/argparse.html#module-argparse

Creating hidden arguments with Python argparse

<p>Is it possible to add an Argument to an python <a href="http://docs.python.org/library/argparse.html#module-argparse" target="_blank" rel="noopener noreferrer"><code>argparse.ArgumentParser</code></a> without it showing up in the usage or help (<code>script.py --help</code>)?</p>


The classifiers in machine learning packages like liblinear and nltk offer a method `show_most_informative_features()`, which is really helpful for debugging features:

    viagra = None          ok : spam     =      4.5 : 1.0
    hello = True           ok : spam     =      4.5 : 1.0
    hello = None           spam : ok     =      3.3 : 1.0
    viagra = True          spam : ok     =      3.3 : 1.0
    casino = True          spam : ok     =      2.0 : 1.0
    casino = None          ok : spam     =      1.5 : 1.0

My question is if something similar is implemented for the classifiers in scikit-learn. I searched the documentation, but couldn&#39;t find anything the like.

If there is no such function yet, does somebody know a workaround how to get to those values?



How to get most informative features for scikit-learn classifiers?

I tried to use the [`norecursedirs`](http://pytest.org/latest/customize.html#confval-norecursedirs) option inside setup.cfg to tell py.test not to collect tests from certain directories but it seems it does ignore it.

    [tool:pytest]
    norecursedirs=lib/third

When I run `py.test` I do see how it does get tests from inside `lib/third`!



How to tell py.test to skip certain directories?

The other day I came across a Python implementation called Jython.  
With Jython you can write Java applications with Python and compile them to pure Java.  
  
I was wondering: Android programming is done with Java.  
So, is it possible to make Android apps with Jython?  

Programming Android apps in jython

I got some simple code:

    def find(str, ch):
        for ltr in str:
            if ltr == ch:
                return str.index(ltr)
    find(&quot;ooottat&quot;, &quot;o&quot;)

The function only return the first index. If I change return to print, it will print 0 0 0. Why is this and is there any way to get `0 1 2`? 

How to find char in string and get all the indexes?

I find myself typing `import numpy as np` almost every single time I fire up the python interpreter. How do I set up the python or ipython interpreter so that numpy is automatically imported?

Automatically import modules when entering the python or ipython interpreter

Given:

    import argparse
    
    pa = argparse.ArgumentParser()
    pa.add_argument(&#39;--foo&#39;)
    pa.add_argument(&#39;--bar&#39;)
    
    print pa.parse_args(&#39;--foo 1&#39;.split())

how do I

- make at least one of &quot;foo, bar&quot; mandatory: `--foo x`, `--bar y` and `--foo x --bar y` are fine
- make at most one of &quot;foo, bar&quot; mandatory: `--foo x` or `--bar y` are fine, `--foo x --bar y` is not

Require either of two arguments using argparse

My python script needs to read files from a directory passed on the command line. I have defined a readable_dir type as below to be used with argparse for validating that the  directory passed on the command line is existent and readable.
Additionally, a default value (/tmp/non_existent_dir in the example below) has also been specified for the directory argument.
The problem here is that argparse invokes readable_dir() on the default value even in a situation where a directory argument is explicitly passed in on the command line. This causes the script to crap out as the default path /tmp/non_existent_dir does not exist in a context where a directory is explicitly passed in on the command line.
I could get around this by not specifying a default value and making this argument mandatory, or by deferring the validation until later in the script but is a more elegant solution that anyone is aware of?



    #!/usr/bin/python
    import argparse
    import os
    
    def readable_dir(prospective_dir):
      if not os.path.isdir(prospective_dir):
        raise Exception(&quot;readable_dir:{0} is not a valid path&quot;.format(prospective_dir))
      if os.access(prospective_dir, os.R_OK):
        return prospective_dir
      else:
        raise Exception(&quot;readable_dir:{0} is not a readable dir&quot;.format(prospective_dir))
    
    parser = argparse.ArgumentParser(description=&#39;test&#39;, fromfile_prefix_chars=&quot;@&quot;)
    parser.add_argument(&#39;-l&#39;, &#39;--launch_directory&#39;, type=readable_dir, default=&#39;/tmp/non_existent_dir&#39;)
    args = parser.parse_args()
    


directory path types with argparse

I am currently using argparse like this:

    import argparse
    from argparse import ArgumentParser

    parser = ArgumentParser(description=&quot;ikjMatrix multiplication&quot;)
    parser.add_argument(&quot;-i&quot;, dest=&quot;filename&quot;, required=True,
        help=&quot;input file with two matrices&quot;, metavar=&quot;FILE&quot;)
    args = parser.parse_args()

    A, B = read(args.filename)
    C = ikjMatrixProduct(A, B)
    printMatrix(C)

Now I would like to note, that the argument of `-i` should be a readable file. How can I do that?


I&#39;ve tried adding `type=open`, `type=argparse.FileType(&#39;r&#39;)` and they worked, but if the file is not valid, I would like to get an error message. How can I do that?

File as command line argument for argparse - error message if argument is not valid

Suppose I have the following argparse snippet:

    diags.cmdln_parser.add_argument( &#39;--scan-time&#39;,
                         action  = &#39;store&#39;,
                         nargs   = &#39;?&#39;,
                         type    = int,
                         default = 5,
                         help    = &quot;Wait SCAN-TIME seconds between status checks.&quot;)

Currently, `--help` returns:

&lt;!-- language: lang-none --&gt;

    usage: connection_check.py [-h]
                                 [--version] [--scan-time [SCAN_TIME]]

              Test the reliability/uptime of a connection.
              
              

    optional arguments:
    -h, --help            show this help message and exit
    --version             show program&#39;s version number and exit
    --scan-time [SCAN_TIME]
                        Wait SCAN-TIME seconds between status checks.

I would prefer something like:

&lt;!-- language: lang-none --&gt;

    --scan-time [SCAN_TIME]
                        Wait SCAN-TIME seconds between status checks.
                        (Default = 5)

Peeking at the help formatter code revealed limited options.  Is there a clever way to get `argparse` to print the default value for `--scan-time` in a similar fashion, or should I just subclass the `help` formatter?

 


Argparse: Way to include default values in &#39;--help&#39;?

Optparse, the old version just ignores all unrecognised arguments and carries on.  In most situations, this isn&#39;t ideal and was changed in argparse.  But there are a few situations where you want to ignore any unrecognised arguments and parse the ones you&#39;ve specified.

For example:

    parser = argparse.ArgumentParser()
    parser.add_argument(&#39;--foo&#39;, dest=&quot;foo&quot;)
    parser.parse_args()

    $python myscript.py --foo 1 --bar 2
    error: unrecognized arguments: --bar

Is there anyway to overwrite this? 

Content Type	Original Author	Original Content on Stackoverflow
Question	Peter Smit	View Question on Stackoverflow
Solution 1 - Python	srgerg	View Answer on Stackoverflow
Solution 2 - Python	rob boudrie	View Answer on Stackoverflow

Creating hidden arguments with Python argparse

Python Problem Overview

Python Solutions

Solution 1 - Python

Solution 2 - Python

Scala Doubles, and Precision

How does the String class override the + operator?

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