Just use [rstrip()][1].

    result = your_string.rstrip(&#39;,&#39;)


  [1]: https://docs.python.org/2/library/string.html#string.rstrip

    str = &#39;test1,test2,test3,&#39;
    str[:-1] # &#39;test1,test2,test3&#39;

**The question is very old but tries to give the better answer**

    str = &#39;test1,test2,test3,&#39;

It will check the last character, if the last character is a comma it will remove otherwise will return the original string.

    result = str[:-1] if str[-1]==&#39;,&#39; else str

Though it is little bit over work for something like that. I think this statement will help you.

    str = &#39;test1,test2,test3,&#39;    
    result = &#39;,&#39;.join([s for s in str.split(&#39;,&#39;) if s]) # &#39;test1,test2,test3&#39;

I would like to change the name of an item in an enum type in PostgreSQL 9.1.5.  

Here is the type&#39;s create stmt:

    CREATE TYPE import_action AS ENUM
    (&#39;Ignored&#39;,
    &#39;Inserted&#39;,
    &#39;Updated&#39;,
    &#39;Task created&#39;);

I just want to change &#39;Task created&#39; to &#39;Aborted&#39;.  It seems like from the [documentation][1], that the following should work:

    ALTER TYPE import_action
    RENAME ATTRIBUTE &quot;Task created&quot; TO &quot;Aborted&quot;; 

However, I get a msg:

    ********** Error **********
    
    ERROR: relation &quot;import_action&quot; does not exist
    SQL state: 42P01

But, it clearly does exist.

The type is currently being used by more than one table. 

I&#39;m being to think that there must not be a way to do this.  I&#39;ve tried the dialog for the type in pgAdminIII, but there is no way that I can see to rename the it there.  (So, either a strong hint that I can&#39;t do it, or - I&#39;m hoping - a small oversight be the developer that created that dialog)

If I can&#39;t do this in one statment?  Then what do I need to do?  Will I have to write a script to add the item, update all of the records to new value, then drop the old item?  Will that even work?

It&#39;s seems like this should be a simple thing.  As I understand it, the records are just storing a reference to the type and item.  I don&#39;t think they are actually store the text value that I have given it.  But, maybe I&#39;m wrong here as well.


  [1]: http://www.postgresql.org/docs/9.1/static/sql-altertype.html

Rename enum item in PostgreSQL

I know that this is not possible and Apple planned it this way to force the users to upgrade their devices. But I just want to know if there is some workaround or hacks in able to do this? The client insists that we should still support armv6 because of a still &quot;large&quot; percentage of the app users.

I know a command called `lipo` to merge static libraries and I read somewhere that we can also use it to merge ipa files but I&#39;m not sure how its exactly done. I did a couple of searching around already on google and this site, buts its hard to find a concrete answer.

How to support both armv6 and armv7s for release build in xcode 4.5

Input

    str = &#39;test1,test2,test3,&#39;

Ouput 

    str = &#39;test1,test2,test3&#39;

Requirement to strip the last occurence of &#39;,&#39;

String function to strip the last comma

Input
<pre><code class="hljs language-ini">str = 'test1,test2,test3,'
</code></pre>
Ouput
<pre><code class="hljs language-ini">str = 'test1,test2,test3'
</code></pre>
Requirement to strip the last occurence of ','

I have a date and I need to make it time zone aware.


    local_tz = timezone(&#39;Asia/Tokyo&#39;)
    start_date = &#39;2012-09-27&#39;
    start_date = datetime.strptime(start_date, &quot;%Y-%m-%d&quot;)   
    start_date = start_date.astimezone(local_tz)

    
    now_utc = datetime.now(timezone(&#39;UTC&#39;))
    local_now = now_utc.astimezone(local_tz)


I need to find if this is true:

    print start_date&gt;local_now


But I get this error.
   

       start_date = start_date.astimezone(local_tz)
       ValueError: astimezone() cannot be applied to a naive datetime

I convert utc to tokyo with no issue.  I need to make start_date timezone aware ad well in tokyo.

Thanks




 




pytz and astimezone() cannot be applied to a naive datetime

For this function

    def eat_dog(name, should_digest=True):
        print &quot;ate dog named %s. Digested, too? %&quot; % (name, str(should_digest))

I want to, external to the function, read its arguments and any default values attached. So for this specific example, I want to know that `name` has no default value (i.e. that it is a required argument) and that `True` is the default value for `should_digest`.

I&#39;m aware of `inspect.getargspec()`, which does give me information about arguments and default values, but I see no connection between the two:

`ArgSpec(args=[&#39;name&#39;, &#39;should_digest&#39;], varargs=None, keywords=None, defaults=(True,))`

From this output how can I tell that `True` (in the `defaults` tuple) is the default value for `should_digest`?

Additionally, I&#39;m aware of the &quot;ask for forgiveness&quot; model of approaching a problem, but unfortunately output from that error won&#39;t tell me the name of the missing argument:

    &gt;&gt;&gt; eat_dog()
    Traceback (most recent call last):
      File &quot;&lt;stdin&gt;&quot;, line 1, in &lt;module&gt;
    TypeError: eat_dog() takes at least 1 argument (0 given)

To give context (why I want to do this), I&#39;m exposing functions in a module over a JSON API. If the caller omits certain function arguments, I want to return a specific error that names the specific function argument that was omitted. If a client omits an argument, but there&#39;s a default provided in the function signature, I want to use that default.

Get a function argument&#39;s default value?

I am designing a RESTful API using Python and Flask. As expected, the API needs to receive an API request and return data if all goes well, but in the instance of an error, it needs to fail softly and return the proper error. I typically raise exceptions when an error results, but in this case I need to return the error message to the user (try-catch block?).

The way I am currently dealing with errors is to have my functions return both the data and an error, and to check for the data at each level, finally returning either the data or the error to the caller of the API function.

The problem with this is that it can get cumbersome when there are several levels of function calls, requiring my functions to pass data and errors several times and perform checks each time.

Is there a better way to do this? What are some improvements I could make to make the error propagation more simple and elegant?

Here is an example of the way I&#39;m currently returning errors:

    def get_data()
        data1, error = get_some_data() # function not shown
        if data1 is None:
             return None, &quot;could not retrieve data1&quot;
        data2, error = get_some_other_data() # function not shown
        if data2 is None:
             return None, &quot;could not retrieve data2&quot;
        return (data1, data2), None

    @app.route(&quot;/api/method&quot;, methods=[&#39;GET&#39;])
    def method():
        data, error = get_data()
        if data is None:
            if error is None:
                error = &quot;unknown error&quot;
            return json.dumps({ &quot;error&quot;: error }), 500
        return json.dumps({ &quot;data&quot;: data }), 200


Returning API Error Messages with Python and Flask

I wrote this simple function:


    def padded_hex(i, l):
        given_int = i
        given_len = l
    
        hex_result = hex(given_int)[2:] # remove &#39;0x&#39; from beginning of str
        num_hex_chars = len(hex_result)
        extra_zeros = &#39;0&#39; * (given_len - num_hex_chars) # may not get used..
    
        return (&#39;0x&#39; + hex_result if num_hex_chars == given_len else
                &#39;?&#39; * given_len if num_hex_chars &gt; given_len else
                &#39;0x&#39; + extra_zeros + hex_result if num_hex_chars &lt; given_len else
                None)

Examples:

    padded_hex(42,4) # result &#39;0x002a&#39;
    hex(15) # result &#39;0xf&#39;
    padded_hex(15,1) # result &#39;0xf&#39;

Whilst this is clear enough for me and fits my use case (a simple test tool for a simple printer) I can&#39;t help thinking there&#39;s a lot of room for improvement and this could be squashed down to something very concise.

What other approaches are there to this problem?

Decorating Hex function to pad zeros

In a project using SciPy and NumPy, should I use `scipy.pi`, `numpy.pi`, or `math.pi`?


Content Type	Original Author	Original Content on Stackoverflow
Question	user1050619	View Question on Stackoverflow
Solution 1 - Python	Amber	View Answer on Stackoverflow
Solution 2 - Python	Antonin Duroy	View Answer on Stackoverflow
Solution 3 - Python	Usman Shabbir	View Answer on Stackoverflow
Solution 4 - Python	Akhter-uz-zaman	View Answer on Stackoverflow

String function to strip the last comma

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How to support both armv6 and armv7s for release build in xcode 4.5

Rename enum item in PostgreSQL

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