An alternative to `defaultdict` is to use the `setdefault` method of standard dictionaries:

     result = {}
     for widget_type, app in widgets:
         result.setdefault(widget_type, []).append(app)

This relies on the fact that lists are mutable, so what is returned from setdefault is the same list as the one in the dictionary, therefore you can append to it.

You can use a `defaultdict(list)`.

    from collections import defaultdict

    result = defaultdict(list)
    for widget_type, app in widgets:
        result[widget_type].append(app)



may be a bit slow but works

    result = {}
    for widget_type, app in widgets:
        result[widget_type] = result.get(widget_type, []) + [app]

My question is almost exactly this question:

[https://stackoverflow.com/questions/3900044/clone-textview-to-append-it-to-a-viewgroup][1]

However, I was inflating a view, and then attempting to clone it at the object level for performance reasons (I don&#39;t want to parse XML every single time), so that answer doesn&#39;t help me. View.clone() is protected and it apparently doesn&#39;t have a copy constructor. Is there any way to do this?


  [1]: https://stackoverflow.com/questions/3900044/clone-textview-to-append-it-to-a-viewgroup

How do I clone a View?

Normally, if you spawn a background thread or run an NSOperation on an NSOperationQueue you need to create an NSAutoreleasePool for that thread or operation because none exists by default.  

Does the same rule apply to a block that is placed within a Grand Central Dispatch queue and will be run on a non-main thread?  That is, do you need to create an NSAutoreleasePool within each block you dispatch to anything other than the main queue?

In my limited testing, I don&#39;t see the console warnings for autoreleased objects that you normally see with background threads or NSOperations.  However, I can&#39;t seem to find definitive documentation on this, so I was wondering if someone could point out where this is stated.


Do you need to create an NSAutoreleasePool within a block in GCD?

Can this Python code be shortened and still be readable using itertools and sets?

    result = {}
    for widget_type, app in widgets:
        if widget_type not in result:
            result[widget_type] = []
        result[widget_type].append(app)


I can think of this only:

    widget_types = zip(*widgets)[0]
    dict([k, [v for w, v in widgets if w == k]) for k in set(widget_types)])

Create or append to a list in a dictionary - can this be shortened?

Can this Python code be shortened and still be readable using itertools and sets?
<pre><code class="hljs language-ini">result = {}
for widget_type, app in widgets:
 if widget_type not in result:
 result[widget_type] = []
 result[widget_type].append(app)
</code></pre>
I can think of this only:
<pre><code class="hljs language-scss">widget_types = zip(*widgets)[0]
dict([k, [v for w, v in widgets if w == k]) for k in set(widget_types)])
</code></pre>

I have a django site with lots of models and forms. I have many custom forms and formsets and inlineformsets and custom validation and custom querysets. Hence the add model action depends on forms that need other things, and the &#39;add model&#39; in the django admin throughs a 500 from a custom queryset.

Is there anyway to disable the &#39;Add $MODEL&#39; functionality for a certain models?

I want ``/admin/appname/modelname/add/`` to give a 404 (or suitable &#39;go away&#39; error message), I don&#39;t want the &#39;Add $MODELNAME&#39; button to be on ``/admin/appname/modelname`` view.

Django admin provides a way to disable admin actions (http://docs.djangoproject.com/en/dev/ref/contrib/admin/actions/#disabling-actions) however the only action for this model is &#39;delete_selected&#39;. i.e. the admin actions only act on existing models. Is there some django-esque way to do this?

Django Admin - Disable the &#39;Add&#39; action for a specific model

If I have the follow 2 sets of code, how do I glue them together?

    void
    c_function(void *ptr) {
        int i;
    
        for (i = 0; i &lt; 10; i++) {
            printf(&quot;%p&quot;, ptr[i]);
        }
    
        return;
    }
    
    
    def python_routine(y):
        x = []
        for e in y:
            x.append(e)

    
   How can I call the c_function with a contiguous list of elements in x?  I tried to cast x to a c_void_p, but that didn&#39;t work.  

I also tried to use something like 

    x = c_void_p * 10 
    for e in y:
        x[i] = e

but this gets a syntax error. 

The C code clearly wants the address of an array.  How do I get this to happen?

How do I convert a Python list into a C array by using ctypes?

I&#39;m using standard python logging module in my python application:
&lt;pre&gt;
import logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(&quot;log&quot;)
while True:
  logger.debug(&#39;Stupid log message &quot; + &#39; &#39;.join([str(i) for i in range(20)]) )
  # Do something
&lt;/pre&gt;

The issue is that although debug level is not enable, that stupid log message is evaluated on each loop iteration, which harms performance badly.

__Is there any solution for this?__

In C++ we have `log4cxx` package that provides macros like this:&lt;br&gt;
`    LOG4CXX_DEBUG(logger, messasage)` &lt;br&gt;
That effectively evaluates to 
&lt;pre&gt;
if (log4cxx::debugEnabled(logger)) {
    log4cxx.log(logger,log4cxx::LOG4CXX_DEBUG, message)
}
&lt;/pre&gt;
But since there are no macros in Python (AFAIK), if there a efficient way to do logging?


Lazy logger message string evaluation

Can someone provide the steps needed to install python version 2.7 on SUSE and RedHat?  It version that is on there is like 2.4 and I need to have it at at least 2.6 to make my script work.
So after the install, I can type Python in a xTerm and get the Python 2.7 command line interface.

On linux SUSE or RedHat, how do I load Python 2.7

Somewhere in the bowels of my code I have something like:

    logger = logging.getLogger(&#39;debug0.x&#39;)

The way I understand it, this should **only** respond when I have previously done something like:

    logging.basicConfig(filename=&#39;10Nov2010a.txt&#39;,level=logging.DEBUG, name=&#39;debug0&#39;)

note that **name** has been defined as **debug0**. However, I have discovered that if do

    logging.basicConfig(filename=&#39;10Nov2010a.txt&#39;,level=logging.DEBUG)

without the **name** keyword, then the *debug0.x* logger defined above reacts, and writes to the log file. I was thinking it would only react in the first case, when the logger had been named.

I&#39;m confused.

Logging hierarchy vs. root logger?

I was wondering if anybody knew where I could obtain dictionaries of positive and negative words.  I&#39;m looking into sentiment analysis and this is a crucial part of it.

Sentiment Analysis Dictionaries

How do I create a Dictionary where I can store functions?

Thanks.


I have about 30+ functions which can be executed from the user. I want to be able to execute the function this way:


       private void functionName(arg1, arg2, arg3)
       {
           // code
       }

       dictionaryName.add(&quot;doSomething&quot;, functionName);

        private void interceptCommand(string command)
        {
            foreach ( var cmd in dictionaryName )
            {
                if ( cmd.Key.Equals(command) )
                {
                    cmd.Value.Invoke();
                }
            }
        }

However, the function signature is not always the same, thus having different amount of arguments. 

C# Store functions in a Dictionary

In some legacy code i have see the following extension method to facilitate adding a new key-value item or updating the value, if the key already exists.


Method-1 (legacy code).

    public static void CreateNewOrUpdateExisting&lt;TKey, TValue&gt;(
        this IDictionary&lt;TKey, TValue&gt; map, TKey key, TValue value)
    {            
        if (map.ContainsKey(key))
        {
            map[key] = value;
        }
        else
        {
            map.Add(key, value);
        }
    }

Though, I have checked that `map[key]=value`  does exactly the same job. That is, this method could be replace with Method-2 below.

Method-2.

    public static void CreateNewOrUpdateExisting&lt;TKey, TValue&gt;(
        this IDictionary&lt;TKey, TValue&gt; map, TKey key, TValue value)
    {
        map[key] = value;
    }

Now, my question is.. Could there be any problem if i replace Method-1 by Method-2? Will it break in any possible scenario?

Also, I think this used to be the difference between HashTable and Dictionary. HashTable allows updating an item, or adding a new item by using indexer while Dictionary does not!! Is this difference been eliminated in C# &gt; 3.0 versions?

The objective of this method is not too throw exception if user sends the same key-value again, the method should just update the entry with the new value, and to make a new entry if new key-value pair has been send to the method.



Method to Add new or update existing item in Dictionary

Is there a way in C++ to search for the mapped value (instead of the key) of a map, and then return the key? Usually, I do `someMap.find(someKey)-&gt;second` to get the value, but here I want to do the opposite and obtain the key (the values and keys are all unique).

Find mapped value of map

I have a Dictionary below:

    colors = {
        &quot;blue&quot; : &quot;5&quot;,
        &quot;red&quot; : &quot;6&quot;,
        &quot;yellow&quot; : &quot;8&quot;,
    }

How do I index the first entry in the dictionary?

`colors[0]` will return a `KeyError` for obvious reasons.

Content Type	Original Author	Original Content on Stackoverflow
Question	culebrón	View Question on Stackoverflow
Solution 1 - Python	Daniel Roseman	View Answer on Stackoverflow
Solution 2 - Python	Mark Byers	View Answer on Stackoverflow
Solution 3 - Python	user1139002	View Answer on Stackoverflow

Create or append to a list in a dictionary - can this be shortened?

Python Problem Overview

Python Solutions

Solution 1 - Python

Solution 2 - Python

Solution 3 - Python

Do you need to create an NSAutoreleasePool within a block in GCD?

How do I clone a View?

Attributions