Besides the Jeff Hardy blog post on [Django + IronPython][1] mentioned by Tony Meyer, it might be useful to also read Jeff&#39;s two other posts in the same series on his struggles with IronPython, easy_install and zlib. The first is [Solving the zlib problem][2] which discusses the absence of zlib for IronPython; hence, no easyinstall. Jeff reimplemented zlib based on ComponentAce&#39;s zlib.net. And finally, in [easy_install on IronPython, Part Deux][3] Jeff discusses some final tweaks that are needed before easy_install can be used with IronPython.


  [1]: http://jdhardy.blogspot.com/2008/12/django-ironpython.html
  [2]: http://jdhardy.blogspot.com/2008/12/solving-zlib-problem-ironpythonzlib.html
  [3]: http://jdhardy.blogspot.com/2008/12/easyinstall-on-ironpython-part-deux.html

[Here&#39;s a database provider that runs on .NET &amp; that works with Django][1]


  [1]: http://blogs.msdn.com/dinoviehland/archive/2008/03/17/ironpython-ms-sql-and-pep-249.aspx

This was [demoed][1] at last year&#39;s PyCon (the [details][2] are also available).  More recently, [Jeff Hardy has blogged about this][3], including suggestions.


  [1]: http://www.infoq.com/news/2008/03/django-and-ironpython
  [2]: http://blogs.msdn.com/dinoviehland/archive/2008/03/17/ironpython-ms-sql-and-pep-249.aspx
  [3]: http://jdhardy.blogspot.com/2008/12/django-ironpython.html

I don&#39;t think Django is yet working on IronPython, but I&#39;m not saying it cannot be done.

[Django-ironpython][1] project is a work currently underway to run Django on IronPython. The project has reported [65.7% test pass rate][2] with sqlite on 2nd of May 2010.  

  [1]: http://bitbucket.org/jdhardy/django-ironpython/overview
  [2]: http://twitter.com/#!/djangoipy

Here&#39;s what I&#39;m trying to do. I&#39;m querying an XML file using LINQ to XML, which gives me an IEnumerable`&lt;T`&gt; object, where T is my &quot;Village&quot; class, filled with the results of this query. Some results are duplicated, so I would like to perform a Distinct() on the IEnumerable&lt;Village&gt; object, like so:

    public IEnumerable&lt;Village&gt; GetAllAlliances()
    {
        try
        {
            IEnumerable&lt;Village&gt; alliances =
                 from alliance in xmlDoc.Elements(&quot;Village&quot;)
                 where alliance.Element(&quot;AllianceName&quot;).Value != String.Empty
                 orderby alliance.Element(&quot;AllianceName&quot;).Value
                 select new Village
                 {
                     AllianceName = alliance.Element(&quot;AllianceName&quot;).Value
                 };
                 
            // TODO: make it work...
            return alliances.Distinct(new AllianceComparer());
        }
        catch (Exception ex)
        {
            throw new Exception(&quot;GetAllAlliances&quot;, ex);
        }
    }

As the default comparer would not work for the Village object, I implemented a custom one, as seen here in the AllianceComparer class:

    public class AllianceComparer : IEqualityComparer&lt;Village&gt;
    {
        #region IEqualityComparer&lt;Village&gt; Members
        bool IEqualityComparer&lt;Village&gt;.Equals(Village x, Village y)
        {
            // Check whether the compared objects reference the same data.
            if (Object.ReferenceEquals(x, y)) 
                return true;

            // Check whether any of the compared objects is null.
            if (Object.ReferenceEquals(x, null) || Object.ReferenceEquals(y, null))
                return false;

            return x.AllianceName == y.AllianceName;
        }

        int IEqualityComparer&lt;Village&gt;.GetHashCode(Village obj)
        {
            return obj.GetHashCode();
        }
        #endregion
    }

The Distinct() method doesn&#39;t work, as I have exactly the same number of results with or without it. Another thing, and I don&#39;t know if it&#39;s usually possible, but I cannot step into AllianceComparer.Equals() to see what could be the problem.&lt;br/&gt;
I&#39;ve found examples of this on the Internet, but I can&#39;t seem to make my implementation work.

Hopefully, someone here might see what could be wrong here!
Thanks in advance!

C# Distinct on IEnumerable&lt;T&gt; with custom IEqualityComparer

I&#39;m working on creating a call back function for an ASP.NET cache item removal event.

The documentation says I should call a method on an object or calls I know will exist (will be in scope), such as a static method, but it said I need to ensure the static is thread safe.

Part 1: What are some examples of things I could do to make it un-thread safe?

Part 2: Does this mean that if I have

    static int addOne(int someNumber){
        int foo = someNumber;
        return foo +1; 
    }

and I call Class.addOne(5); and Class.addOne(6); simutaneously, Might I get 6 or 7 returned depending on who which invocation sets foo first? (i.e. a race condition)

How do I know if this C# method is thread safe?

I am interested in getting an install of Django running on IronPython, has anyone had any success getting this running with some level of success?  

If so can you please tell of your experiences, performance, suggest some tips, resources and gotchas?

Django on IronPython

<p>I am interested in getting an install of Django running on IronPython, has anyone had any success getting this running with some level of success?</p>
<p>If so can you please tell of your experiences, performance, suggest some tips, resources and gotchas?</p>


When I read Django code I often see in models what is called a &quot;slug&quot;. I am not quite sure what this is, but I do know it has something to do with URLs. How and when is this slug-thing supposed to be used? 

(I have read its definition in [this glossary][1].)

  [1]: http://docs.djangoproject.com/en/dev/glossary/



What is a &quot;slug&quot; in Django?

Suppose I have a Python function as defined below:

    def foo(arg1,arg2):
        #do something with args
        a = arg1 + arg2
        return a

I can get the name of the function using `foo.func_name`. How can I programmatically get its source code, as I typed above?


How can I get the source code of a Python function?

I&#39;d like to split strings like these

    &#39;foofo21&#39;
    &#39;bar432&#39;
    &#39;foobar12345&#39;


into

    [&#39;foofo&#39;, &#39;21&#39;]
    [&#39;bar&#39;, &#39;432&#39;]
    [&#39;foobar&#39;, &#39;12345&#39;]

Does somebody know an easy and simple way to do this in python?

How to split strings into text and number?

`cd` is the shell command to change the working directory.

How do I change the current working directory in Python?


Equivalent of shell &#39;cd&#39; command to change the working directory?

When I&#39;m moving through a file with a csv.reader, how do I return to the top of the file.   If I were doing it with a normal file I could just do something like &quot;file.seek(0)&quot;.  Is there anything like that for the csv module?

Thanks ahead of time ;)

Python csv.reader: How do I return to the top of the file?

I have 

    class Cab(models.Model):
        name  = models.CharField( max_length=20 )
        descr = models.CharField( max_length=2000 )

    class Cab_Admin(admin.ModelAdmin):
        ordering     = (&#39;name&#39;,)
        list_display = (&#39;name&#39;,&#39;descr&#39;, )
        # what to write here to make descr using TextArea?

    admin.site.register( Cab, Cab_Admin )


how to assign TextArea widget to &#39;descr&#39; field in admin interface?

**upd:**  
In __Admin__ interface only!

Good idea to use ModelForm.

Django-Admin: CharField as TextArea

I am trying to build the search for a Django site I am building, and in that search, I am searching in three different models. And to get pagination on the search result list, I would like to use a generic object_list view to display the results. But to do that, I have to merge three querysets into one.

How can I do that? I&#39;ve tried this:

    result_list = []
    page_list = Page.objects.filter(
        Q(title__icontains=cleaned_search_term) |
        Q(body__icontains=cleaned_search_term))
    article_list = Article.objects.filter(
        Q(title__icontains=cleaned_search_term) |
        Q(body__icontains=cleaned_search_term) |
        Q(tags__icontains=cleaned_search_term))
    post_list = Post.objects.filter(
        Q(title__icontains=cleaned_search_term) |
        Q(body__icontains=cleaned_search_term) |
        Q(tags__icontains=cleaned_search_term))

    for x in page_list:
        result_list.append(x)
    for x in article_list:
        result_list.append(x)
    for x in post_list:
        result_list.append(x)

    return object_list(
        request,
        queryset=result_list,
        template_object_name=&#39;result&#39;,
        paginate_by=10,
        extra_context={
            &#39;search_term&#39;: search_term},
        template_name=&quot;search/result_list.html&quot;)

But this doesn&#39;t work. I get an error when I try to use that list in the generic view. The list is missing the clone attribute.

How can I merge the three lists, `page_list`, `article_list` and `post_list`?





How can I combine two or more querysets in a Django view?

I have some stuff in settings.py that I&#39;d like to be able to access from a template, but I can&#39;t figure out how to do it. I already tried

    {{CONSTANT_NAME}}

but that doesn&#39;t seem to work. Is this possible?

Can I access constants in settings.py from templates in Django?

I have model Foo which has field bar. The bar field should be unique, but allow nulls in it, meaning I want to allow more than one record if bar field is `null`, but if it is not `null` the values must be unique.

Here is my model:

    class Foo(models.Model):
        name = models.CharField(max_length=40)
        bar = models.CharField(max_length=40, unique=True, blank=True, null=True, default=None)

And here is the corresponding SQL for the table:

    CREATE TABLE appl_foo
    (
        id serial NOT NULL,
         &quot;name&quot; character varying(40) NOT NULL,
        bar character varying(40),
        CONSTRAINT appl_foo_pkey PRIMARY KEY (id),
        CONSTRAINT appl_foo_bar_key UNIQUE (bar)
    )	

When using admin interface to create more than 1 foo objects where bar is null it gives me an error: &quot;Foo with this Bar already exists.&quot;

However when I insert into database (PostgreSQL):

    insert into appl_foo (&quot;name&quot;, bar) values (&#39;test1&#39;, null)
    insert into appl_foo (&quot;name&quot;, bar) values (&#39;test2&#39;, null)

This works, just fine, it allows me to insert more than 1 record with bar being null, so the database allows me to do what I want, it&#39;s just something wrong with the Django model. Any ideas?

&lt;b&gt;EDIT&lt;/b&gt;

The portability of the solution as far as DB is not an issue, we are happy with Postgres. 
I&#39;ve tried setting unique to a callable, which was my function returning True/False for specific values of _bar_, it didn&#39;t give any errors, however seamed like it had no effect at all.

So far, I&#39;ve removed the unique specifier from the _bar_ property and handling the _bar_ uniqueness in the application, however still looking for a more elegant solution. Any recommendations?


Unique fields that allow nulls in Django

What&#39;s the simplest way to do a find and replace for a given input string, say `abc`, and replace with another string, say `XYZ` in file `/tmp/file.txt`?

I am writting an app and using IronPython to execute commands through SSH &amp;mdash; but I don&#39;t know Unix that well and don&#39;t know what to look for.

I have heard that Bash, apart from being a command line interface, can be a very powerful scripting language. So, if this is true, I assume you can perform actions like these.

Can I do it with bash, and what&#39;s the simplest (one line) script to achieve my goal?

Find and Replace Inside a Text File from a Bash Command

I want to access some .NET assemblies written in C# from Python code. 

A little research showed I have two choices:

 - [IronPython][1] with .NET interface capability/support built-in
 - Python with the [Python .NET][2] package

What are the trade-offs between both solutions?

  [1]: http://www.codeplex.com/IronPython
  [2]: https://github.com/pythonnet/pythonnet

IronPython vs. Python .NET

Is there a way to call Python code, using IronPython I assume, from C#? If so, how?

How can I call (Iron)Python code from a C# app?

Anyone can share a working example on how to call a simple C# library (actually its WPF) from python code? (I have tried using IronPython and had too much trouble with unsupported  CPython library my python code is using so I thought of trying the other way around and calling my C# code from Python). 

Here is the example I was playing with: 


    using System.Runtime.InteropServices;
    using System.EnterpriseServices;

    namespace DataViewerLibrary
    {
        public interface ISimpleProvider
        {
           [DispIdAttribute(0)]
           void Start();
        }
    
        [ComVisible(true)]
        [ClassInterface(ClassInterfaceType.None)]
        public class PlotData : ServicedComponent, ISimpleProvider
        {
           public void Start()
           {
              Plot plotter = new Plot();
              plotter.ShowDialog();
           }
        }
    }
Plotter is a WPF windows that plots an Ellipse

I don&#39;t know how to call this code from my python all. Any suggestions? 



Calling a C# library from python

This sort of question has been asked before in varying degrees, but I feel it has not been answered in a concise way and so I ask it again.

I want to run a script in Python. Let&#39;s say it&#39;s this:

    if __name__ == &#39;__main__&#39;:
        with open(sys.argv[1], &#39;r&#39;) as f:
            s = f.read()
        print s

Which gets a file location, reads it, then prints its contents. Not so complicated.

Okay, so how do I run this in C#?

This is what I have now:

        private void run_cmd(string cmd, string args)
        {
            ProcessStartInfo start = new ProcessStartInfo();
            start.FileName = cmd;
            start.Arguments = args;
            start.UseShellExecute = false;
            start.RedirectStandardOutput = true;
            using (Process process = Process.Start(start))
            {
                using (StreamReader reader = process.StandardOutput)
                {
                    string result = reader.ReadToEnd();
                    Console.Write(result);
                }
            }
        }

When I pass the `code.py` location as `cmd` and the `filename` location as `args` it doesn&#39;t work. I was told I should pass `python.exe` as the `cmd`, and then `code.py filename` as the `args`.

I have been looking for a while now and can only find people suggesting to use IronPython or such. But there must be a way to call a Python script from C#.

Some clarification:

I need to run it from C#, I need to capture the output, and I can&#39;t use IronPython or anything else. Whatever hack you have will be fine.

P.S.: The actual Python code I&#39;m running is much more complex than this, and it returns output which I need in C#, and the C# code will be constantly calling the Python code.

Pretend this is my code:

        private void get_vals()
        {
            for (int i = 0; i &lt; 100; i++)
            {
                run_cmd(&quot;code.py&quot;, i);
            }
        }


Content Type	Original Author	Original Content on Stackoverflow
Question	Xian	View Question on Stackoverflow
Solution 1 - Python	Serx	View Answer on Stackoverflow
Solution 2 - Python	bchhun	View Answer on Stackoverflow
Solution 3 - Python	Tony Meyer	View Answer on Stackoverflow
Solution 4 - Python	jsalonen	View Answer on Stackoverflow

Django on IronPython

Python Problem Overview

Python Solutions

Solution 1 - Python

Solution 2 - Python

Solution 3 - Python

Solution 4 - Python

How do I know if this C# method is thread safe?

C# Distinct on IEnumerable<T> with custom IEqualityComparer

Attributions