You need to expand the tilde manually:

    my_dir = os.path.expanduser(&#39;~/some_dir&#39;)


The conversion of `~/some_dir` to `$HOME/some_dir` is called [tilde expansion](http://www.gnu.org/software/bash/manual/bashref.html#Tilde-Expansion) and is a common user interface feature. The file system does not know anything about it.

In Python, this feature is implemented by [os.path.expanduser](http://docs.python.org/library/os.path.html#os.path.expanduser):

    my_dir = os.path.expanduser(&quot;~/some_dir&quot;)

That&#39;s probably because Python is not Bash and doesn&#39;t follow same conventions. You may use this:

    homedir = os.path.expanduser(&#39;~&#39;)

When I&#39;m editing a large file, I often want to have it open in two editing windows at once (eg. for reference, or because I&#39;m working on two different parts of the file at once). 

Is there any way to do this with Eclipse?



Eclipse: have the same file open in two editors?

I&#39;m wondering whether to use matrix or query parameters in my URLs. I found an older [discussion][1] to that topic not satisfying.

Examples

- URL with query params: http://some.where/thing?paramA=1&amp;paramB=6542
- URL with matrix params: http://some.where/thing;paramA=1;paramB=6542

At first sight matrix params seem to have only advantages:

 - more readable
 - no encoding and decoding of &quot;&amp;&quot; in XML documents is required
 - URLs with &quot;?&quot; are not cached in many cases; URLs with matrix params are cached
 - matrix parameters can appear everywhere in the path and are not limited to its end
 - matrix parameters can have more than one value: `paramA=val1,val2`
 
But there are also disadvantages:

 - only a few frameworks like [JAX-RS][2] support matrix parameters
 - When a browser submits a form via GET, the params become query params. So it ends up in two kinds of parameters for the same task. To not confuse users of the REST services and limit the effort for the developers of the services, it would be easier to use always query params - in this area.

Since the developer of the service can choose a framework with matrix param support, the only remaining disadvantage would be that browsers create by default query parameters.

Are there any other disadvantages? What would you do?


  [1]: https://stackoverflow.com/questions/401981/when-to-use-query-parameters-versus-matrix-parameters
  [2]: https://jsr311.dev.java.net/

URL matrix parameters vs. query parameters

I have a little problem with `~` in my paths.

This code example creates some directories called `~/some_dir` and do not understand that I wanted to create `some_dir` in my home directory.

    my_dir = &quot;~/some_dir&quot;
    if not os.path.exists(my_dir):
        os.makedirs(my_dir)

Note this is on a Linux-based system.


os.makedirs doesn&#39;t understand &quot;~&quot; in my path

I have a little problem with <code>~</code> in my paths.
This code example creates some directories called <code>~/some_dir</code> and do not understand that I wanted to create <code>some_dir</code> in my home directory.
<pre><code class="hljs language-lua">my_dir = "~/some_dir"
if not os.path.exists(my_dir):
 os.makedirs(my_dir)
</code></pre>
Note this is on a Linux-based system.

How could I get the version defined in `setup.py` from my package (for `--version`, or other purposes)?

How can I get the version defined in setup.py (setuptools) in my package?

How would you go about formatting a long line such as this? I&#39;d like to get it to no more than 80 characters wide:

    logger.info(&quot;Skipping {0} because its thumbnail was already in our system as {1}.&quot;.format(line[indexes[&#39;url&#39;]], video.title))

Is this my best option?

    url = &quot;Skipping {0} because its thumbnail was already in our system as {1}.&quot;
    logger.info(url.format(line[indexes[&#39;url&#39;]], video.title))


How can I break up this long line in Python?

I need to analyze sound written in a .wav file. For that I need to transform this file into set of numbers (arrays, for example). I think I need to use the wave package. However, I do not know how exactly it works. For example I did the following:


    import wave
    w = wave.open(&#39;/usr/share/sounds/ekiga/voicemail.wav&#39;, &#39;r&#39;)
    for i in range(w.getnframes()):
        frame = w.readframes(i)
        print frame

As a result of this code I expected to see sound pressure as function of time. In contrast I see a lot of strange, mysterious symbols (which are not hexadecimal numbers). Can anybody, pleas, help me with that?

Reading *.wav files in Python

I am building a class which subclasses &lt;code&gt;dict&lt;/code&gt;, and overrides &lt;code&gt;\__setitem__&lt;/code&gt;. I would like to be certain that my method will be called in all instances where dictionary items could possibly be set.

I have discovered three situations where Python (in this case, 2.6.4) does not call my overridden &lt;code&gt;\__setitem__&lt;/code&gt; method when setting values, and instead calls &lt;code&gt;PyDict_SetItem&lt;/code&gt; directly

1. In the constructor
1. In the &lt;code&gt;setdefault&lt;/code&gt; method
1. In the &lt;code&gt;update&lt;/code&gt; method

As a very simple test:

    class MyDict(dict):
        def __setitem__(self, key, value):
            print &quot;Here&quot;
            super(MyDict, self).__setitem__(key, str(value).upper())

    &gt;&gt;&gt; a = MyDict(abc=123)
    &gt;&gt;&gt; a[&#39;def&#39;] = 234
    Here
    &gt;&gt;&gt; a.update({&#39;ghi&#39;: 345})
    &gt;&gt;&gt; a.setdefault(&#39;jkl&#39;, 456)
    456
    &gt;&gt;&gt; print a
    {&#39;jkl&#39;: 456, &#39;abc&#39;: 123, &#39;ghi&#39;: 345, &#39;def&#39;: &#39;234&#39;}

You can see that the overridden method is only called when setting the items explicitly. To get Python to always call my &lt;code&gt;\__setitem__&lt;/code&gt; method, I have had to reimplement those three methods, like this:

    class MyUpdateDict(dict):
        def __init__(self, *args, **kwargs):
            self.update(*args, **kwargs)

        def __setitem__(self, key, value):
            print &quot;Here&quot;
            super(MyUpdateDict, self).__setitem__(key, value)

        def update(self, *args, **kwargs):
            if args:
                if len(args) &gt; 1:
                    raise TypeError(&quot;update expected at most 1 arguments, got %d&quot; % len(args))
                other = dict(args[0])
                for key in other:
                    self[key] = other[key]
            for key in kwargs:
                self[key] = kwargs[key]

        def setdefault(self, key, value=None):
            if key not in self:
                self[key] = value
            return self[key]

Are there any other methods which I need to override, in order to know that Python will *always* call my &lt;code&gt;\__setitem__&lt;/code&gt; method?

**UPDATE**

Per gs&#39;s suggestion, I&#39;ve tried subclassing UserDict (actually, IterableUserDict, since I want to iterate over the keys) like this:

    from UserDict import *;
    class MyUserDict(IterableUserDict):
        def __init__(self, *args, **kwargs):
            UserDict.__init__(self,*args,**kwargs)

        def __setitem__(self, key, value):
            print &quot;Here&quot;
            UserDict.__setitem__(self,key, value)

This class seems to correctly call my &lt;code&gt;\__setitem__&lt;/code&gt; on &lt;code&gt;setdefault&lt;/code&gt;, but it doesn&#39;t call it on &lt;code&gt;update&lt;/code&gt;, or when initial data is provided to the constructor.

**UPDATE 2**

Peter Hansen&#39;s suggestion got me to look more carefully at dictobject.c, and I realised that the update method could be simplified a bit, since the built-in dictionary constructor simply calls the built-in update method anyway. It now looks like this:

    def update(self, *args, **kwargs):
        if len(args) &gt; 1:
            raise TypeError(&quot;update expected at most 1 arguments, got %d&quot; % len(args))
        other = dict(*args, **kwargs)
        for key in other:
            self[key] = other[key]


Subclassing Python dictionary to override __setitem__

I&#39;ve always used dictionaries. I write in Python.

What is the true difference between a dictionary and a hash table?

What is the difference between semaphores and mutex provided by pthread library ?

pthreads mutex vs semaphore

While running a C program, It says *&quot;(core dumped)&quot;* but I can&#39;t see any files under the current path.

I have set and verified the `ulimit`:

    ulimit -c unlimited 
    ulimit -a 

I also tried to find a file named &quot;core&quot;, but didn&#39;t get the core dumped file?  
Any help, where is my core file?


Core dumped, but core file is not in the current directory?

Using Linux, I want to compare two SQLite databases that have the same schema.
There will be just a few differences.

Is there a tool that would output these differences?
Preferably output them to the command line, so that I can grep/sed them.

SQLite uses SQL, so a general SQL tool might also do.

How to compare two SQLite databases on Linux

I have a log file in .csv format in Linux, that is being updated continuously.
I want to view the log file as it is being updated. Is there any Linux command(s) to do that?

View a log file in Linux dynamically

I have a file as below:

    line1
    line2
    line3

And I want to get:

    prefixline1
    prefixline2
    prefixline3

I could write a Ruby script, but it is better if I do not need to.

`prefix` will contain `/`. It is a path, `/opt/workdir/` for example.


Add a prefix string to beginning of each line

my scripts rely heavily on external programs and scripts.
I need to be sure that a program I need to call exists. 
Manually, I&#39;d check this using &#39;which&#39; in the commandline.

Is there an equivalent to `File.exists?` for things in `$PATH`?

(yes I guess I could parse `%x[which scriptINeedToRun]` but that&#39;s not super elegant.

Thanks!
yannick

---

UPDATE: Here&#39;s the solution I retained:

   

     def command?(command)
           system(&quot;which #{ command} &gt; /dev/null 2&gt;&amp;1&quot;)
     end


--- 

### UPDATE 2: A few new answers have come in - at least some of these offer better solutions. 

### Update 3: The [ptools gem][1] has adds a &quot;which&quot; method to the File class. 


  [1]: https://github.com/djberg96/ptools

&quot;which in ruby&quot;: Checking if program exists in $PATH from ruby

I&#39;ve got a SVN Repository that has moved to a new address/path. However, I&#39;ve got a working copy with uncommitted source code still pointing to the old (now invalid) repository path. How do you change a working copy to point at a new repository?

SVN - Change working copy to point at new svn path

This is what I have:

    glob(os.path.join(&#39;src&#39;,&#39;*.c&#39;))

but I want to search the subfolders of src. Something like this would work:

    glob(os.path.join(&#39;src&#39;,&#39;*.c&#39;))
    glob(os.path.join(&#39;src&#39;,&#39;*&#39;,&#39;*.c&#39;))
    glob(os.path.join(&#39;src&#39;,&#39;*&#39;,&#39;*&#39;,&#39;*.c&#39;))
    glob(os.path.join(&#39;src&#39;,&#39;*&#39;,&#39;*&#39;,&#39;*&#39;,&#39;*.c&#39;))

But this is obviously limited and clunky.

How to use glob() to find files recursively?

So I&#39;m running this javascript, and everything works fine, except the paths to the background image. It works on my local ASP.NET Dev environment, but it does NOT work when deployed to a server in a virtual directory.

This is in an external .js file, folder structure is

    Site/Content/style.css
    Site/Scripts/myjsfile.js
    Site/Images/filters_expand.jpg
    Site/Images/filters_colapse.jpg
    
then this is where the js file is included from

    Site/Views/ProductList/Index.aspx

    $(&quot;#toggle&quot;).click(function() {
        if (left.width() &gt; 0) {
            AnimateNav(left, right, 0);
            $(this).css(&quot;background&quot;, &quot;url(&#39;../Images/filters_expand.jpg&#39;)&quot;);
        }
        else {
            AnimateNav(left, right, 170);
            $(this).css(&quot;background&quot;, &quot;url(&#39;../Images/filters_collapse.jpg&#39;)&quot;);
        }
    });

I&#39;ve tried using `&#39;/Images/filters_collapse.jpg&#39;` and that doesn&#39;t work either; however, it seems to work on the server if I use `&#39;../../Images/filters_collapse.jpg&#39;`.

Basically, I want have the same functionallity as the ASP.NET tilda -- `~`.

**update**

Are paths in external .js files relative to the Page they are included in, or the actual location of the .js file?

Relative Paths in Javascript in an external file

Inspired by &quot;https://stackoverflow.com/questions/59895/can-a-bash-script-tell-which-directory-it-is-stored-in&quot;, what&#39;s the Ruby way to do this?


Content Type	Original Author	Original Content on Stackoverflow
Question	Johan	View Question on Stackoverflow
Solution 1 - Python	SilentGhost	View Answer on Stackoverflow
Solution 2 - Python	ddaa	View Answer on Stackoverflow
Solution 3 - Python	gruszczy	View Answer on Stackoverflow

os.makedirs doesn't understand "~" in my path

Python Problem Overview

Python Solutions

Solution 1 - Python

Solution 2 - Python

Solution 3 - Python

URL matrix parameters vs. query parameters

Eclipse: have the same file open in two editors?

Attributions