A time range doesn&#39;t exist as a standalone index type. Generate using a single date

    In [1]: pandas.date_range(&quot;11:00&quot;, &quot;21:30&quot;, freq=&quot;30min&quot;)
    Out[1]: 
    &lt;class &#39;pandas.tseries.index.DatetimeIndex&#39;&gt;
    [2013-07-14 11:00:00, ..., 2013-07-14 21:30:00]
    Length: 22, Freq: 30T, Timezone: None

The time objects
    
    In [2]: pandas.date_range(&quot;11:00&quot;, &quot;21:30&quot;, freq=&quot;30min&quot;).time
    Out[2]: 
    array([datetime.time(11, 0), datetime.time(11, 30), datetime.time(12, 0),
           datetime.time(12, 30), datetime.time(13, 0), datetime.time(13, 30),
           datetime.time(14, 0), datetime.time(14, 30), datetime.time(15, 0),
           datetime.time(15, 30), datetime.time(16, 0), datetime.time(16, 30),
           datetime.time(17, 0), datetime.time(17, 30), datetime.time(18, 0),
           datetime.time(18, 30), datetime.time(19, 0), datetime.time(19, 30),
           datetime.time(20, 0), datetime.time(20, 30), datetime.time(21, 0),
           datetime.time(21, 30)], dtype=object)

You can also resample if you are spanning multiple dates.

What are you trying to do?

I am trying to understand why an async void method in an ASP.Net application can result in the following exception, while it appears that async Task will not:

    System.InvalidOperationException: An asynchronous module or handler 
    completed while an asynchronous operation was still pending

I am relatively new to the world of async in .NET, but do feel like I&#39;ve tried to run this one down via a number of existing resources, including all of the following:

 - [What&#39;s the difference between returning void and returning a Task?][1]
 - [It&#39;s All About the SynchronizationContext][2]
 - [Async Syntactic Sugar Suggestions][3]
 - [Async in ASP.NET][4]

From these resources, I understand the best practice is to typically return Task and avoid async void.  I also understand that async void increments the count of outstanding operations when the method is called and decrements it when it is completed.  This sounds like at least part of the answer to my question.  However, what I am missing is what happens when I return Task and why doing so makes things &quot;work&quot;.

Here is a contrived example to further illustrate my question:

&lt;!-- language: c# --&gt;

    public class HomeController : AsyncController
    {
    	// This method will work fine
        public async Task&lt;ActionResult&gt; ThisPageWillLoad()
        {
    		// Do not await the task since it is meant to be fire and forget
    		var task = this.FireAndForgetTask();
    
            return await Task.FromResult(this.View(&quot;Index&quot;));
        }
    
    	private async Task FireAndForgetTask()
    	{
    		var task = Task.Delay(TimeSpan.FromSeconds(3));
    		await task;
    	}
    
    	// This method will throw the following exception:
    	// System.InvalidOperationException: An asynchronous module or 
        // handler completed while an asynchronous operation was still pending
    	public async Task&lt;ActionResult&gt; ThisPageWillNotLoad()
    	{
    		// Obviously can&#39;t await a void method
    		this.FireAndForgetVoid();
    
    		return await Task.FromResult(this.View(&quot;Index&quot;));
    	}
    
    	private async void FireAndForgetVoid()
    	{
    		var task = Task.Delay(TimeSpan.FromSeconds(3));
    		await task;
    	}
    }

On a related note, if my understanding of async void is correct, then isn&#39;t it kind of wrong to think of async void as &quot;fire and forget&quot; in this scenario since ASP.Net is not actually forgetting about it?

  [1]: https://stackoverflow.com/questions/8043296/whats-the-difference-between-returning-void-and-returning-a-task
  [2]: http://msdn.microsoft.com/en-us/magazine/gg598924.aspx
  [3]: http://social.msdn.microsoft.com/Forums/en-US/6dbc3f00-b302-4e6b-9b97-419bc242c0d8/async-syntactic-sugar-suggestions
  [4]: http://channel9.msdn.com/Events/aspConf/aspConf/Async-in-ASP-NET


Async Void, ASP.Net, and Count of Outstanding Operations

I have downloaded the MVC Music Store ASP.NET application at location C:\Users\DEVESH\Desktop\Projects\MvcMusicStore-v3.0\MvcMusicStore-Completed\MvcMusicStore 
and added the website on IIS at the same location. I have also given permission to IIS_IUSRS, but when I run localhost I am getting the error:

**HTTP Error 403.14 - Forbidden The Web server is configured to not list the contents of this directory.**

I have googled it, but have not found a fix. What I am doing wrong?

HTTP Error 403.14 - Forbidden The Web server is configured to not list the contents

Is there a way to generate time range in pandas similar to date_range?
something like:

    pandas.time_range(&quot;11:00&quot;, &quot;21:30&quot;, freq=&quot;30min&quot;)

Create hourly/minutely time range using pandas

Is there a way to generate time range in pandas similar to date_range?
something like:
<pre><code class="hljs language-arduino">pandas.time_range("11:00", "21:30", freq="30min")
</code></pre>

In Python you have two fine ways to repeat some action more than once. One of them is `while` loop and the other - `for` loop. So let&#39;s have a look on two simple pieces of code:

    for i in range(n):
        do_sth()

And the other:

    i = 0
    while i &lt; n:
        do_sth()
        i += 1

My question is which of them is better. Of course, the first one, which is very common in documentation examples and various pieces of code you could find around the Internet, is much more elegant and shorter, but on the other hand it creates a completely useless list of integers just to loop over them. Isn&#39;t it a waste of memory, especially as far as big numbers of iterations are concerned?

So what do you think, which way is better?
    

for or while loop to do something n times

Why is `random.shuffle` returning `None` in Python?

    &gt;&gt;&gt; x = [&#39;foo&#39;,&#39;bar&#39;,&#39;black&#39;,&#39;sheep&#39;]
    &gt;&gt;&gt; from random import shuffle
    &gt;&gt;&gt; print shuffle(x)
    None

How do I get the shuffled value instead of `None`?

Why does random.shuffle return None?

Using python I am wanting to post a message to the OSX Notification Center.
What library do I need to use?  should i write a program in objective-c and then call that program from python? 


----------
**update**

How do I access the features of notification center for 10.9 such as the buttons and the text field?

Python post osx notification

I already have an existing Database that has a lot of tables and a lot of data in `MySQL`. I intend to create a `Flask` app and use sqlalchemy along with it. Now I asked out on irc and looked around on google and tried the following ideas:

**First** I used [sqlacodegen][1] to generate the models from my `DB`. But then I was confused about it a little and looked some more. And I found [this][2].

This looked like an elegant solution.

So **Second**, I rewrote my `models.py` according to the solution there and now I am even more confused. I am looking for the best approach to build this flask app along with the already existing DB. 

I looked into the flask documentation but didnt really get any help for a project with an already existing db. There is a lot of good stuff for creating something from scratch, creating the db and all. But I am really confused.

Please Note that its my first day with `Flask`, but I have experience with `Django`, so the basic concepts are not a hurdle. I need some guidance in choosing the best approach for this usecase. A detailed explanation would be greatly appreciated. By detailed I definitely do not expect someone to write all the code and spoon feed me on this, but just enough to get me started, that is integrate this db seamlessly into `flask` via `sqlalchemy`. Note my DB is in `MySQL`.


  [1]: https://pypi.python.org/pypi/sqlacodegen
  [2]: http://flask.pocoo.org/mailinglist/archive/2012/5/23/flask-sqlalchemy-with-pre-existing-database/#9974419419ee1960c88c98689f6aee9d

How to build a flask application around an already existing database?

    vec = [[1,2,3], [4,5,6], [7,8,9]]
    print [num for elem in vec for num in elem]      &lt;----- this

    &gt;&gt;&gt; [1, 2, 3, 4, 5, 6, 7, 8, 9]

This is tricking me out.  
I understand elem is the lists inside of the list from `for elem in vic`  
I don&#39;t quite understand the usage of `num` and `for num in elem` in the beginning and the end.

How does python interpret this?  
What&#39;s the order it looks at?

python list comprehension double for

How do you round up/ round down a [momentjs](http://momentjs.com/docs/) moment to nearest minute?

I have checked the [docs](http://momentjs.com/docs/), but there doesn&#39;t appear to be a method for this.

Note that I do not want a string rounded to the nearest minute, I want a `moment` returned (or modified in place, either is fine). I prefer not to have to convert to a string, and the convert back too.

Thanks.

----

As requested, here is some code:

    var now = new moment(new Date());

	if (now.seconds() &gt; 0) {
	    now.add(&#39;minutes&#39;, -1);
	}

	now.seconds(0);


as you can see, I have managed to manually round down the moment here, but it seems rather hacky. Just after a more elegant way of accomplishing this.


round up/ round down a momentjs moment to nearest minute

I have a quick question regarding dates and times in x-axis in GNUPLOT. I&#39;ll let the code do the talking:

This is my data:

    #Time	Data in	Data out
    &quot;2013-07-22 15:59:00&quot;	6286	3730
    &quot;2013-07-22 15:58:00&quot;	10695	14589
    &quot;2013-07-22 15:57:00&quot;	17868	26464
    &quot;2013-07-22 15:56:00&quot;	18880	34012
    &quot;2013-07-22 15:55:00&quot;	19206	41192
    &quot;2013-07-22 15:54:00&quot;	20365	43218
    &quot;2013-07-22 15:53:00&quot;	18459	39298
    &quot;2013-07-22 15:52:00&quot;	3420	4686
    &quot;2013-07-22 15:51:00&quot;	3256	4942

And this is the code that is generating the graph:

    gnuplot&gt; set title &quot;Data usage over the last 24 hours&quot;
    gnuplot&gt; unset multiplot
    gnuplot&gt; set xdata time
    gnuplot&gt; set style data lines  
    gnuplot&gt; set term png
    Terminal type set to &#39;png&#39;
    Options are &#39;nocrop font &quot;arial,12&quot; fontscale 1.0 size 640,480 &#39;
    gnuplot&gt; set timefmt &quot;%Y-%m-%d %H:%M:%S&quot;
    gnuplot&gt; set format x &quot;%m-%d\n%H:%M&quot;
    gnuplot&gt; set xlabel &quot;Time&quot;
    gnuplot&gt; set ylabel &quot;Traffic&quot; 
    gnuplot&gt; set autoscale y  
    gnuplot&gt; set xrange [&quot;2013-07-21 16:00&quot;:&quot;2013-07-22 16:00&quot;]
    gnuplot&gt; set output &quot;datausage.png&quot;
    gnuplot&gt; plot &quot;C:\\Users\\blah\\Desktop\\plot.tmp&quot; using 1:2 t &quot;inbound&quot; w lines, &quot;C:\\Users\\blah\\Desktop\\plot.tmp&quot; u 1:3 t &quot;outbound&quot; w lines
                                                                                                                                                                     ^
             all points y value undefined!


Is the problem the space in between `date` and `time` in the x-axis? If not, what do you think could be the problem?

Gnuplot date/time in x axis

I need to parse and manipulate Times without Dates in my code. For example i might get the string &quot;15:00&quot; from a timepicker. I want to turn this into a Time object of some kind - I normally work in Python which has distinct Date, Time, and Datetime objects.

However all the solutions i&#39;ve seen focus on using the Date object. This cannot parse a string like &quot;15:00&quot; since it requires day information. I don&#39;t want to add arbitrary Date information to Times - especially since Date appears to make assumptions about things like daylight saving depending on the day and the locale, and there appears to be a risk of it automatically attempting to translate the time into a given locale. Furthermore I want to be able to add times, e.g. &quot;15:00 + 1 hour&quot;

What is the recommended solution to parse and handle &quot;raw&quot; times not associated to dates?

Javascript parsing Times without Date

I&#39;m currently attempting to display the user&#39;s time without displaying the seconds. Is there a way I can do this using Javascript&#39;s .toLocaleTimeString()?

Doing something like this:

    var date = new Date();
    var string = date.toLocaleTimeString();
will display the user&#39;s time with every unit, e.g. currently it displays 3:39:15 PM. Am I able to display that same string, just without the seconds? (e.g. 3:39 PM)

How do I use .toLocaleTimeString() without displaying seconds?

I have this program that calculates the time taken to answer a specific question, and quits out of the while loop when answer is incorrect, but i want to delete the last calculation, so i can call `min()` and it not be the wrong time, sorry if this is confusing.

    from time import time
    
    q = input(&#39;What do you want to type? &#39;)
    a = &#39; &#39;
    record = []
    while a != &#39;&#39;:
        start = time()
        a = input(&#39;Type: &#39;)
        end = time()
        v = end-start
        record.append(v)
        if a == q:
            print(&#39;Time taken to type name: {:.2f}&#39;.format(v))
        else:
            break
    for i in record:
        print(&#39;{:.2f} seconds.&#39;.format(i))



How to delete last item in list?

I have a pandas dataframe in the following format:

    df = pd.DataFrame([[1.1, 1.1, 1.1, 2.6, 2.5, 3.4,2.6,2.6,3.4,3.4,2.6,1.1,1.1,3.3], list(&#39;AAABBBBABCBDDD&#39;), [1.1, 1.7, 2.5, 2.6, 3.3, 3.8,4.0,4.2,4.3,4.5,4.6,4.7,4.7,4.8], [&#39;x/y/z&#39;,&#39;x/y&#39;,&#39;x/y/z/n&#39;,&#39;x/u&#39;,&#39;x&#39;,&#39;x/u/v&#39;,&#39;x/y/z&#39;,&#39;x&#39;,&#39;x/u/v/b&#39;,&#39;-&#39;,&#39;x/y&#39;,&#39;x/y/z&#39;,&#39;x&#39;,&#39;x/u/v/w&#39;],[&#39;1&#39;,&#39;3&#39;,&#39;3&#39;,&#39;2&#39;,&#39;4&#39;,&#39;2&#39;,&#39;5&#39;,&#39;3&#39;,&#39;6&#39;,&#39;3&#39;,&#39;5&#39;,&#39;1&#39;,&#39;1&#39;,&#39;1&#39;]]).T
    df.columns = [&#39;col1&#39;,&#39;col2&#39;,&#39;col3&#39;,&#39;col4&#39;,&#39;col5&#39;]

df:

       col1 col2 col3     col4 col5
    0   1.1    A  1.1    x/y/z    1
    1   1.1    A  1.7      x/y    3
    2   1.1    A  2.5  x/y/z/n    3
    3   2.6    B  2.6      x/u    2
    4   2.5    B  3.3        x    4
    5   3.4    B  3.8    x/u/v    2
    6   2.6    B    4    x/y/z    5
    7   2.6    A  4.2        x    3
    8   3.4    B  4.3  x/u/v/b    6
    9   3.4    C  4.5        -    3
    10  2.6    B  4.6      x/y    5
    11  1.1    D  4.7    x/y/z    1
    12  1.1    D  4.7        x    1
    13  3.3    D  4.8  x/u/v/w    1

Now I want to group this by two columns like following:

    df.groupby([&#39;col5&#39;,&#39;col2&#39;]).reset_index()
OutPut:

                 index col1 col2 col3     col4 col5
    col5 col2                                      
    1    A    0      0  1.1    A  1.1    x/y/z    1
         D    0     11  1.1    D  4.7    x/y/z    1
              1     12  1.1    D  4.7        x    1
              2     13  3.3    D  4.8  x/u/v/w    1
    2    B    0      3  2.6    B  2.6      x/u    2
              1      5  3.4    B  3.8    x/u/v    2
    3    A    0      1  1.1    A  1.7      x/y    3
              1      2  1.1    A  2.5  x/y/z/n    3
              2      7  2.6    A  4.2        x    3
         C    0      9  3.4    C  4.5        -    3
    4    B    0      4  2.5    B  3.3        x    4
    5    B    0      6  2.6    B    4    x/y/z    5
              1     10  2.6    B  4.6      x/y    5
    6    B    0      8  3.4    B  4.3  x/u/v/b    6

I want to get the count by each row like following.
Expected Output:

    col5 col2 count
    1    A      1
         D      3
    2    B      2
    etc...

How to get my expected output? And I want to find largest count for each &#39;col2&#39; value?

Pandas DataFrame Groupby two columns and get counts

    import pandas as pd
    date_stngs = (&#39;2008-12-20&#39;,&#39;2008-12-21&#39;,&#39;2008-12-22&#39;,&#39;2008-12-23&#39;)

    a = pd.Series(range(4),index = (range(4)))

    for idx, date in enumerate(date_stngs):
        a[idx]= pd.to_datetime(date)

This code bit produces error: 

&gt; TypeError:&quot; &#39;int&#39; object is not iterable&quot;

Can anyone tell me how to get this series of date time strings into a DataFrame as `DateTime` objects?

In Pandas how do I convert a string of date strings to datetime objects and put them in a DataFrame?

I want to create a count of unique values from one of my Pandas dataframe columns and then add a new column with those counts to my original data frame. I&#39;ve tried a couple different things. I created a pandas series and then calculated counts with the value_counts method. I tried to merge these values back to my original dataframe, but I the keys that I want to merge on are in the Index(ix/loc).

    Color Value
    Red   100
    Red   150
    Blue  50

I want to return something like:

    Color Value Counts
    Red   100   2
    Red   150   2 
    Blue  50    1

Create column of value_counts in Pandas dataframe

I just installed pandas and statsmodels package on my python 2.7
When I tried  &quot;import pandas as pd&quot;, this error message comes out.
Can anyone help? Thanks!!!

    numpy.dtype has the wrong size, try recompiling
    Traceback (most recent call last):
      File &quot;&lt;stdin&gt;&quot;, line 1, in &lt;module&gt;
      File &quot;C:\analytics\ext\python27\lib\site-packages\statsmodels-0.5.0-py2.7-win32.egg\statsmodels\formula\__init__.py&quot;,
    line 4, in &lt;module&gt;
        from formulatools import handle_formula_data
      File &quot;C:\analytics\ext\python27\lib\site-packages\statsmodels-0.5.0-py2.7-win32.egg\statsmodels\formula\formulatools.p
    y&quot;, line 1, in &lt;module&gt;
        import statsmodels.tools.data as data_util
      File &quot;C:\analytics\ext\python27\lib\site-packages\statsmodels-0.5.0-py2.7-win32.egg\statsmodels\tools\__init__.py&quot;, li
    ne 1, in &lt;module&gt;
        from tools import add_constant, categorical
      File &quot;C:\analytics\ext\python27\lib\site-packages\statsmodels-0.5.0-py2.7-win32.egg\statsmodels\tools\tools.py&quot;, line
    14, in &lt;module&gt;
        from pandas import DataFrame
      File &quot;C:\analytics\ext\python27\lib\site-packages\pandas\__init__.py&quot;, line 6, in &lt;module&gt;
        from . import hashtable, tslib, lib
      File &quot;numpy.pxd&quot;, line 157, in init pandas.tslib (pandas\tslib.c:49133)
    ValueError: numpy.dtype has the wrong size, try recompiling

ValueError: numpy.dtype has the wrong size, try recompiling

this is a rather similar question to [this question](https://stackoverflow.com/questions/13842088/set-value-for-particular-cell-in-pandas-dataframe &quot;Set value for particular cell in pandas DataFrame&quot;) but with one key difference: I&#39;m selecting the data I want to change not by its index but by some criteria.

If the criteria I apply return a single row, I&#39;d expect to be able to set the value of a certain column in that row in an easy way, but my first attempt doesn&#39;t work:

    &gt;&gt;&gt; d = pd.DataFrame({&#39;year&#39;:[2008,2008,2008,2008,2009,2009,2009,2009], 
    ...                   &#39;flavour&#39;:[&#39;strawberry&#39;,&#39;strawberry&#39;,&#39;banana&#39;,&#39;banana&#39;,
    ...                   &#39;strawberry&#39;,&#39;strawberry&#39;,&#39;banana&#39;,&#39;banana&#39;],
    ...                   &#39;day&#39;:[&#39;sat&#39;,&#39;sun&#39;,&#39;sat&#39;,&#39;sun&#39;,&#39;sat&#39;,&#39;sun&#39;,&#39;sat&#39;,&#39;sun&#39;],
    ...                   &#39;sales&#39;:[10,12,22,23,11,13,23,24]})

    &gt;&gt;&gt; d
       day     flavour  sales  year
    0  sat  strawberry     10  2008
    1  sun  strawberry     12  2008
    2  sat      banana     22  2008
    3  sun      banana     23  2008
    4  sat  strawberry     11  2009
    5  sun  strawberry     13  2009
    6  sat      banana     23  2009
    7  sun      banana     24  2009

    &gt;&gt;&gt; d[d.sales==24]
       day flavour  sales  year
    7  sun  banana     24  2009

    &gt;&gt;&gt; d[d.sales==24].sales = 100
    &gt;&gt;&gt; d
       day     flavour  sales  year
    0  sat  strawberry     10  2008
    1  sun  strawberry     12  2008
    2  sat      banana     22  2008
    3  sun      banana     23  2008
    4  sat  strawberry     11  2009
    5  sun  strawberry     13  2009
    6  sat      banana     23  2009
    7  sun      banana     24  2009

So rather than setting 2009 Sunday&#39;s Banana sales to 100, nothing happens! What&#39;s the nicest way to do this? Ideally the solution should use the row number, as you normally don&#39;t know that in advance!

Replace value for a selected cell in pandas DataFrame without using index

One frequently finds expressions of this type in python questions on SO. Either for just accessing all items of the iterable

    for i in range(len(a)):
        print(a[i])

Which is just a clumbersome way of writing:

    for e in a:
        print(e)

Or for assigning to elements of the iterable:

    for i in range(len(a)):
        a[i] = a[i] * 2

Which should be the same as:

    for i, e in enumerate(a):
         a[i] = e * 2
    # Or if it isn&#39;t too expensive to create a new iterable
    a = [e * 2 for e in a]

Or for filtering over the indices:

    for i in range(len(a)):
        if i % 2 == 1: continue
        print(a[i])

Which could be expressed like this:

    for e in a [::2]:
        print(e)

Or when you just need the length of the list, and not its content:

    for _ in range(len(a)):
        doSomethingUnrelatedToA()

Which could be:

    for _ in a:
        doSomethingUnrelatedToA()

**In python we have `enumerate`, slicing, `filter`, `sorted`, etc... As python `for` constructs are intended to iterate over iterables and not only ranges of integers, are there real-world use-cases where you need `in range(len(a))`?**

Is there a need for range(len(a))?

As the title suggests, I am trying to figure out a way of generating random numbers using the new C++11 `&lt;random&gt;` library. I have tried it with this code:

    std::default_random_engine generator;
    std::uniform_real_distribution&lt;double&gt; uniform_distance(1, 10.001);

The problem with the code I have is that every time I compile and run it, it always generates the same numbers. So my question is what other functions in the random library can accomplish this while being truly random?

For my particular use case, I was trying to get a value within the range `[1, 10]`

Generate random numbers using C++11 random library

I understand how functions like `range()` and `zip()` can be used in a for loop. However I expected `range()` to output a list - much like `seq` in the unix shell. If I run the following code:

    a=range(10)
    print(a)

The output is `range(10)`, suggesting it&#39;s not a list but a different type of object. `zip()` has a similar behaviour when printed, outputting something like

    &lt;zip object at &quot;hexadecimal number&quot;&gt;

So my question is what are they, what advantages are there to making them this, and how can I get their output to lists without looping over them?


Python range() and zip() object type

How can I create an app that generates a random number in Android using Eclipse and then show the result in a `TextView` field? The random number has to be in a range selected by the user. So, the user will input the max and min of the range, and then I will output the answer.

How can I generate a random number in a certain range?

Go&#39;s range can iterate over maps and slices, but I was wondering if there is a way to iterate over a range of numbers, something like this:

	for i := range [1..10] {
		fmt.Println(i)
	}

Or is there a way to represent range of integers in Go like how Ruby does with the [class Range][1]?

[1]: https://docs.ruby-lang.org/en/2.7.0/Range.html

Content Type	Original Author	Original Content on Stackoverflow
Question	UNagaswamy	View Question on Stackoverflow
Solution 1 - Python	Jeff	View Answer on Stackoverflow

Create hourly/minutely time range using pandas

Python Problem Overview

Python Solutions

Solution 1 - Python

HTTP Error 403.14 - Forbidden The Web server is configured to not list the contents

Async Void, ASP.Net, and Count of Outstanding Operations

Attributions