Programs & Examples On #Django managers

A Manager is the interface through which database query operations are provided to Django models.

spring autowiring with unique beans: Spring expected single matching bean but found 2

For me it was case of having two beans implementing the same interface. One was a fake ban for the sake of unit test which was conflicting with original bean. If we use

@component("suggestionServicefake")

, it still references with suggestionService. So I removed @component and only used

@Qualifier("suggestionServicefake")

which solved the problem

Append values to query string

The following solution works for ASP.NET 5 (vNext) and it uses QueryHelpers class to build a URI with parameters.

    public Uri GetUri()
    {
        var location = _config.Get("http://iberia.com");
        Dictionary<string, string> values = GetDictionaryParameters();

        var uri = Microsoft.AspNetCore.WebUtilities.QueryHelpers.AddQueryString(location, values);
        return new Uri(uri);
    }

    private Dictionary<string,string> GetDictionaryParameters()
    {
        Dictionary<string, string> values = new Dictionary<string, string>
        {
            { "param1", "value1" },
            { "param2", "value2"},
            { "param3", "value3"}
        };
        return values;
    }

The result URI would have http://iberia.com?param1=value1&param2=value2&param3=value3

Add Foreign Key relationship between two Databases

If you need rock solid integrity, have both tables in one database, and use an FK constraint. If your parent table is in another database, nothing prevents anyone from restoring that parent database from an old backup, and then you have orphans.

This is why FK between databases is not supported.

SQL Server - Adding a string to a text column (concat equivalent)

like said before best would be to set datatype of the column to nvarchar(max), but if that's not possible you can do the following using cast or convert:

-- create a test table 
create table test (
    a text
) 
-- insert test value
insert into test (a) values ('this is a text')
-- the following does not work !!!
update test set a = a + ' and a new text added'
-- but this way it works: 
update test set a = cast ( a as nvarchar(max))  + cast (' and a new text added' as nvarchar(max) )
-- test result
select * from test
-- column a contains:
this is a text and a new text added

hope that helps

XmlSerializer: remove unnecessary xsi and xsd namespaces

//Create our own namespaces for the output
XmlSerializerNamespaces ns = new XmlSerializerNamespaces();

//Add an empty namespace and empty value
ns.Add("", "");

//Create the serializer
XmlSerializer slz = new XmlSerializer(someType);

//Serialize the object with our own namespaces (notice the overload)
slz.Serialize(myXmlTextWriter, someObject, ns)

Setting a WebRequest's body data

Update

See my other SO answer.


Original

var request = (HttpWebRequest)WebRequest.Create("https://example.com/endpoint");

string stringData = ""; // place body here
var data = Encoding.Default.GetBytes(stringData); // note: choose appropriate encoding

request.Method = "PUT";
request.ContentType = ""; // place MIME type here
request.ContentLength = data.Length;

var newStream = request.GetRequestStream(); // get a ref to the request body so it can be modified
newStream.Write(data, 0, data.Length);
newStream.Close();

Display Two <div>s Side-by-Side

Try this : (http://jsfiddle.net/TpqVx/)

.left-div {
    float: left;
    width: 100px;
    /*height: 20px;*/
    margin-right: 8px;
    background-color: linen;
}
.right-div {

    margin-left: 108px;
    background-color: lime;
}??

<div class="left-div">
    &nbsp;
</div>
<div class="right-div">
    My requirements are <b>[A]</b> Content in the two divs should line up at the top, <b>[B]</b> Long text in right-div should not wrap underneath left-div, and <b>[C]</b> I do not want to specify a width of right-div. I don't want to set the width of right-div because this markup needs to work within different widths.
</div>
<div style='clear:both;'>&nbsp;</div>

Hints :

  • Just use float:left in your left-most div only.
  • No real reason to use height, but anyway...
  • Good practice to use <div 'clear:both'>&nbsp;</div> after your last div.

fatal: bad default revision 'HEAD'

Note: Git 2.6 (Q3/Q4 2015) will finally provide a more meaningful error message.

See commit ce11360 (29 Aug 2015) by Jeff King (peff).
(Merged by Junio C Hamano -- gitster -- in commit 699a0f3, 02 Sep 2015)

log: diagnose empty HEAD more clearly

If you init or clone an empty repository, the initial message from running "git log" is not very friendly:

$ git init
Initialized empty Git repository in /home/peff/foo/.git/
$ git log
fatal: bad default revision 'HEAD'

Let's detect this situation and write a more friendly message:

$ git log
fatal: your current branch 'master' does not have any commits yet

We also detect the case that 'HEAD' points to a broken ref; this should be even less common, but is easy to see.
Note that we do not diagnose all possible cases. We rely on resolve_ref, which means we do not get information about complex cases. E.g., "--default master" would use dwim_ref to find "refs/heads/master", but we notice only that "master" does not exist.
Similarly, a complex sha1 expression like "--default HEAD^2" will not resolve as a ref.

But that's OK. We fall back to a generic error message in those cases, and they are unlikely to be used anyway.
Catching an empty or broken "HEAD" improves the common case, and the other cases are not regressed.

nodejs send html file to client

Try your code like this:

var app = express();
app.get('/test', function(req, res) {
    res.sendFile('views/test.html', {root: __dirname })
});
  1. Use res.sendFile instead of reading the file manually so express can handle setting the content-type properly for you.

  2. You don't need the app.engine line, as that is handled internally by express.

Join two sql queries

I would just use a Union

In your second query add the extra column name and add a '' in all the corresponding locations in the other queries

Example

//reverse order to get the column names
select top 10 personId, '' from Telephone//No Column name assigned 
Union 
select top 10 personId, loanId from loan

Iterating through a string word by word

for word in string.split():
    print word

AngularJs: How to set radio button checked based on model

Just do something like this,<input type="radio" ng-disabled="loading" name="dateRange" ng-model="filter.DateRange" value="1" ng-checked="(filter.DateRange == 1)"/>

How do I disable text selection with CSS or JavaScript?

You can use JavaScript to do what you want:


if (document.addEventListener !== undefined) {
  // Not IE
  document.addEventListener('click', checkSelection, false);
} else {
  // IE
  document.attachEvent('onclick', checkSelection);
}

function checkSelection() {
    var sel = {};
    if (window.getSelection) {
        // Mozilla
        sel = window.getSelection();
    } else if (document.selection) {
        // IE
        sel = document.selection.createRange();
    }

    // Mozilla
    if (sel.rangeCount) {
        sel.removeAllRanges();
        return;
    }

    // IE
    if (sel.text > '') {
        document.selection.empty();
        return;
    }
}

Soap box: You really shouldn't be screwing with the client's user agent in this manner. If the client wants to select things on the document, then they should be able to select things on the document. It doesn't matter if you don't like the highlight color, because you aren't the one viewing the document.

Finding the indices of matching elements in list in Python

if you're doing a lot of this kind of thing you should consider using numpy.

In [56]: import random, numpy

In [57]: lst = numpy.array([random.uniform(0, 5) for _ in range(1000)]) # example list

In [58]: a, b = 1, 3

In [59]: numpy.flatnonzero((lst > a) & (lst < b))[:10]
Out[59]: array([ 0, 12, 13, 15, 18, 19, 23, 24, 26, 29])

In response to Seanny123's question, I used this timing code:

import numpy, timeit, random

a, b = 1, 3

lst = numpy.array([random.uniform(0, 5) for _ in range(1000)])

def numpy_way():
    numpy.flatnonzero((lst > 1) & (lst < 3))[:10]

def list_comprehension():
    [e for e in lst if 1 < e < 3][:10]

print timeit.timeit(numpy_way)
print timeit.timeit(list_comprehension)

The numpy version is over 60 times faster.

How to add Active Directory user group as login in SQL Server

In SQL Server Management Studio, go to Object Explorer > (your server) > Security > Logins and right-click New Login:

enter image description here

Then in the dialog box that pops up, pick the types of objects you want to see (Groups is disabled by default - check it!) and pick the location where you want to look for your objects (e.g. use Entire Directory) and then find your AD group.

enter image description here

You now have a regular SQL Server Login - just like when you create one for a single AD user. Give that new login the permissions on the databases it needs, and off you go!

Any member of that AD group can now login to SQL Server and use your database.

How do I pass a value from a child back to the parent form?

I think the easiest way is to use the Tag property in your FormOptions class set the Tag = value you need to pass and after the ShowDialog method read it as

myvalue x=(myvalue)formoptions.Tag;

How to add a touch event to a UIView?

You can achieve this by adding Gesture Recogniser in your code.

Step 1: ViewController.m:

// Declare the Gesture.
UITapGestureRecognizer *gesRecognizer = [[UITapGestureRecognizer alloc] 
                                          initWithTarget:self 
                                          action:@selector(handleTap:)];
gesRecognizer.delegate = self;

// Add Gesture to your view.
[yourView addGestureRecognizer:gesRecognizer]; 

Step 2: ViewController.m:

// Declare the Gesture Recogniser handler method.
- (void)handleTap:(UITapGestureRecognizer *)gestureRecognizer{
   NSLog(@"Tapped");
}

NOTE: here yourView in my case was @property (strong, nonatomic) IBOutlet UIView *localView;

EDIT: *localView is the white box in Main.storyboard from below

enter image description here

enter image description here

Responsive design with media query : screen size?

The screen widths Bootstrap v3.x uses are as follows:

  • Extra small devices Phones (<768px) / .col-xs-
  • Small devices Tablets (=768px) / .col-sm-
  • Medium devices Desktops (=992px) / .col-md-
  • Large devices Desktops (=1200px) / .col-lg-

So, these are good to use and work well in practice.

Converting Symbols, Accent Letters to English Alphabet

There is no easy or general way to do what you want because it is just your subjective opinion that these letters look loke the latin letters you want to convert to. They are actually separate letters with their own distinct names and sounds which just happen to superficially look like a latin letter.

If you want that conversion, you have to create your own translation table based on what latin letters you think the non-latin letters should be converted to.

(If you only want to remove diacritial marks, there are some answers in this thread: How do I remove diacritics (accents) from a string in .NET? However you describe a more general problem)

onCreateOptionsMenu inside Fragments

Call

setSupportActionBar(toolbar)

inside

onViewCreated(...) 

of Fragment

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    Toolbar toolbar = (Toolbar) view.findViewById(R.id.toolbar);
    ((MainActivity)getActivity()).setSupportActionBar(toolbar);
    setHasOptionsMenu(true);
}

How can I display a tooltip on an HTML "option" tag?

At least on firefox, you can set a "title" attribute on the option tag:

<option value="" title="Tooltip">Some option</option>

Force "portrait" orientation mode

Don't apply the orientation to the application element, instead you should apply the attribute to the activity element, and you must also set configChanges as noted below.

Example:

<activity
   android:screenOrientation="portrait"
   android:configChanges="orientation|keyboardHidden">
</activity>

This is applied in the manifest file AndroidManifest.xml.

ArrayBuffer to base64 encoded string

Below are 2 simple functions for converting Uint8Array to Base64 String and back again

arrayToBase64String(a) {
    return btoa(String.fromCharCode(...a));
}

base64StringToArray(s) {
    let asciiString = atob(s);
    return new Uint8Array([...asciiString].map(char => char.charCodeAt(0)));
}

How to set UITextField height?

In Swift 3 use:

yourTextField.frame.size.height = 30

What's sizeof(size_t) on 32-bit vs the various 64-bit data models?

size_t is defined by the C standard to be the unsigned integer return type of the sizeof operator (C99 6.3.5.4.4), and the argument of malloc and friends (C99 7.20.3.3 etc). The actual range is set such that the maximum (SIZE_MAX) is at least 65535 (C99 7.18.3.2).

However, this doesn't let us determine sizeof(size_t). The implementation is free to use any representation it likes for size_t - so there is no upper bound on size - and the implementation is also free to define a byte as 16-bits, in which case size_t can be equivalent to unsigned char.

Putting that aside, however, in general you'll have 32-bit size_t on 32-bit programs, and 64-bit on 64-bit programs, regardless of the data model. Generally the data model only affects static data; for example, in GCC:

`-mcmodel=small'
     Generate code for the small code model: the program and its
     symbols must be linked in the lower 2 GB of the address space.
     Pointers are 64 bits.  Programs can be statically or dynamically
     linked.  This is the default code model.

`-mcmodel=kernel'
     Generate code for the kernel code model.  The kernel runs in the
     negative 2 GB of the address space.  This model has to be used for
     Linux kernel code.

`-mcmodel=medium'
     Generate code for the medium model: The program is linked in the
     lower 2 GB of the address space but symbols can be located
     anywhere in the address space.  Programs can be statically or
     dynamically linked, but building of shared libraries are not
     supported with the medium model.

`-mcmodel=large'
     Generate code for the large model: This model makes no assumptions
     about addresses and sizes of sections.

You'll note that pointers are 64-bit in all cases; and there's little point to having 64-bit pointers but not 64-bit sizes, after all.

Is there a way to take the first 1000 rows of a Spark Dataframe?

The method you are looking for is .limit.

Returns a new Dataset by taking the first n rows. The difference between this function and head is that head returns an array while limit returns a new Dataset.

Example usage:

df.limit(1000)

How can I add or update a query string parameter?

My take from here (compatible with "use strict"; does not really use jQuery):

function decodeURIParams(query) {
  if (query == null)
    query = window.location.search;
  if (query[0] == '?')
    query = query.substring(1);

  var params = query.split('&');
  var result = {};
  for (var i = 0; i < params.length; i++) {
    var param = params[i];
    var pos = param.indexOf('=');
    if (pos >= 0) {
        var key = decodeURIComponent(param.substring(0, pos));
        var val = decodeURIComponent(param.substring(pos + 1));
        result[key] = val;
    } else {
        var key = decodeURIComponent(param);
        result[key] = true;
    }
  }
  return result;
}

function encodeURIParams(params, addQuestionMark) {
  var pairs = [];
  for (var key in params) if (params.hasOwnProperty(key)) {
    var value = params[key];
    if (value != null) /* matches null and undefined */ {
      pairs.push(encodeURIComponent(key) + '=' + encodeURIComponent(value))
    }
  }
  if (pairs.length == 0)
    return '';
  return (addQuestionMark ? '?' : '') + pairs.join('&');
}

//// alternative to $.extend if not using jQuery:
// function mergeObjects(destination, source) {
//   for (var key in source) if (source.hasOwnProperty(key)) {
//     destination[key] = source[key];
//   }
//   return destination;
// }

function navigateWithURIParams(newParams) {
  window.location.search = encodeURIParams($.extend(decodeURIParams(), newParams), true);
}

Example usage:

// add/update parameters
navigateWithURIParams({ foo: 'bar', boz: 42 });

// remove parameter
navigateWithURIParams({ foo: null });

// submit the given form by adding/replacing URI parameters (with jQuery)
$('.filter-form').submit(function(e) {
  e.preventDefault();
  navigateWithURIParams(decodeURIParams($(this).serialize()));
});

Add a new column to existing table in a migration

I'll add on to mike3875's answer for future readers using Laravel 5.1 and onward.

To make things quicker, you can use the flag "--table" like this:

php artisan make:migration add_paid_to_users --table="users"

This will add the up and down method content automatically:

/**
 * Run the migrations.
 *
 * @return void
 */
public function up()
{
    Schema::table('users', function (Blueprint $table) {
        //
    });
}

Similarily, you can use the --create["table_name"] option when creating new migrations which will add more boilerplate to your migrations. Small point, but helpful when doing loads of them!

Could not read JSON: Can not deserialize instance of hello.Country[] out of START_OBJECT token

If you want to avoid using an extra Class and List<Object> genomes you could simply use a Map.

The data structure translates into Map<String, List<Country>>

String resourceEndpoint = "http://api.geonames.org/countryInfoJSON?username=volodiaL";

Map<String, List<Country>> geonames = restTemplate.getForObject(resourceEndpoint, Map.class);

List<Country> countries = geonames.get("geonames");

Multiple ping script in Python

This script:

import subprocess
import os
with open(os.devnull, "wb") as limbo:
        for n in xrange(1, 10):
                ip="192.168.0.{0}".format(n)
                result=subprocess.Popen(["ping", "-c", "1", "-n", "-W", "2", ip],
                        stdout=limbo, stderr=limbo).wait()
                if result:
                        print ip, "inactive"
                else:
                        print ip, "active"

will produce something like this output:

192.168.0.1 active
192.168.0.2 active
192.168.0.3 inactive
192.168.0.4 inactive
192.168.0.5 inactive
192.168.0.6 inactive
192.168.0.7 active
192.168.0.8 inactive
192.168.0.9 inactive

You can capture the output if you replace limbo with subprocess.PIPE and use communicate() on the Popen object:

p=Popen( ... )
output=p.communicate()
result=p.wait()

This way you get the return value of the command and can capture the text. Following the manual this is the preferred way to operate a subprocess if you need flexibility:

The underlying process creation and management in this module is handled by the Popen class. It offers a lot of flexibility so that developers are able to handle the less common cases not covered by the convenience functions.

error: No resource identifier found for attribute 'adSize' in package 'com.google.example' main.xml

I've been searching answer but couldn't find but finally I could fix this by adding play-service-ads dependency let's try this:

*) File -> Project Structure... -> Under the module you can find app and there is a option called dependencies and you can add com.google.android.gms:play-services-ads:x.x.x dependency to your project

I faced this problem when I try to import Eclipse projects into Android Studio.

Image

Check if a string contains a string in C++

Use std::string::find as follows:

if (s1.find(s2) != std::string::npos) {
    std::cout << "found!" << '\n';
}

Note: "found!" will be printed if s2 is a substring of s1, both s1 and s2 are of type std::string.

Write a mode method in Java to find the most frequently occurring element in an array

I would use this code. It includes an instancesOf function, and it runs through each number.

public class MathFunctions {

public static int mode(final int[] n) {
    int maxKey = 0;
    int maxCounts = 0;

    for (int i : n) {
        if (instancesOf(i, n) > maxCounts) {
            maxCounts = instancesOf(i, n);
            maxKey = i;
        }
    }

    return maxKey;
}

public static int instancesOf(int n, int[] Array) {
    int occurences = 0;
    for (int j : Array) {
        occurences += j == n ? 1 : 0;
    }
    return occurences;
}

public static void main (String[] args) {
    //TODO Auto-generated method stub
    System.out.println(mode(new int[] {100,200,2,300,300,300,500}));
}
}

I noticed that the code Gubatron posted doesn't work on my computer; it gave me an ArrayIndexOutOfBoundsException.

Loop timer in JavaScript

Note that setTimeout and setInterval are very different functions:

  • setTimeout will execute the code once, after the timeout.
  • setInterval will execute the code forever, in intervals of the provided timeout.

Both functions return a timer ID which you can use to abort the timeout. All you have to do is store that value in a variable and use it as argument to clearTimeout(tid) or clearInterval(tid) respectively.

So, depending on what you want to do, you have two valid choices:

// set timeout
var tid = setTimeout(mycode, 2000);
function mycode() {
  // do some stuff...
  tid = setTimeout(mycode, 2000); // repeat myself
}
function abortTimer() { // to be called when you want to stop the timer
  clearTimeout(tid);
}

or

// set interval
var tid = setInterval(mycode, 2000);
function mycode() {
  // do some stuff...
  // no need to recall the function (it's an interval, it'll loop forever)
}
function abortTimer() { // to be called when you want to stop the timer
  clearInterval(tid);
}

Both are very common ways of achieving the same.

How do you convert CString and std::string std::wstring to each other?

This works fine:

//Convert CString to std::string
inline std::string to_string(const CString& cst)
{
    return CT2A(cst.GetString());
}

Select all 'tr' except the first one

Since tr:not(:first-child) is not supported by IE 6, 7, 8. You can use the help of jQuery. You may find it here

Rebasing remote branches in Git

Nice that you brought this subject up.

This is an important thing/concept in git that a lof of git users would benefit from knowing. git rebase is a very powerful tool and enables you to squash commits together, remove commits etc. But as with any powerful tool, you basically need to know what you're doing or something might go really wrong.

When you are working locally and messing around with your local branches, you can do whatever you like as long as you haven't pushed the changes to the central repository. This means you can rewrite your own history, but not others history. By only messing around with your local stuff, nothing will have any impact on other repositories.

This is why it's important to remember that once you have pushed commits, you should not rebase them later on. The reason why this is important, is that other people might pull in your commits and base their work on your contributions to the code base, and if you later on decide to move that content from one place to another (rebase it) and push those changes, then other people will get problems and have to rebase their code. Now imagine you have 1000 developers :) It just causes a lot of unnecessary rework.

Can Console.Clear be used to only clear a line instead of whole console?

I think I found why there are a few varying answers for this question. When the window has been resized such that it has a horizontal scroll bar (because the buffer is larger than the window) Console.CursorTop seems to return the wrong line. The following code works for me, regardless of window size or cursor position.

public static void ClearLine()
{
    Console.SetCursorPosition(0, Console.CursorTop);
    Console.Write(new string(' ', Console.WindowWidth));
    Console.SetCursorPosition(0, Console.CursorTop - (Console.WindowWidth >= Console.BufferWidth ? 1 : 0));
}

Without the (Console.WindowWidth >= Console.BufferWidth ? 1 : 0), the code may either move the cursor up or down, depending on which version you use from this page, and the state of the window.

Nginx: Permission denied for nginx on Ubuntu

just because you don't have the right to acess the file , use

chmod -R 755 /var/log/nginx;

or you can change to sudo then it

Comparing the contents of two files in Sublime Text

Compare Side-By-Side looks like the most convenient to me though it's not the most popular:

UPD: I need to add that this plugin can freeze ST while comparing big files. It is certainly not the best decision if you are going to compare large texts.

Use mysql_fetch_array() with foreach() instead of while()

the most obvious way to make foreach a possibility includes materializing the whole resultset in an array, which will probably kill you memory-wise, sooner or later. you'd need to turn to iterators to avoid that problem. see http://www.php.net/~helly/php/ext/spl/

What is the best open XML parser for C++?

TiCPP is a "more c++" version of TinyXML.

'TiCPP' is short for the official name TinyXML++. It is a completely new interface to TinyXML (http://www.grinninglizard.com/tinyxml/) that uses MANY of the C++ strengths. Templates, exceptions, and much better error handling. It is also fully documented in doxygen. It is really cool because this version let's you interface tiny the exact same way as before or you can choose to use the new 'ticpp' classes. All you need to do is define TIXML_USE_TICPP. It has been tested in VC 6.0, VC 7.0, VC 7.1, VC 8.0, MinGW gcc 3.4.5, and in Linux GNU gcc 3+

HTML Form: Select-Option vs Datalist-Option

There is another important difference between select and datalist. Here comes the browser support factor.

select is widely supported by browsers compared to datalist. Please take a look at this page for complete browser support of datalist--

Datalist browser support

Where as select is supported in effectively all browsers (since IE6+, Firefox 2+, Chrome 1+ etc)

How do I horizontally center a span element inside a div

another option would be to give the span display:table; and center it via margin:0 auto;

span {
display:table;
margin:0 auto;
}

printf %f with only 2 numbers after the decimal point?

as described in Formatter class, you need to declare precision. %.2f in your case.

Closing pyplot windows

Please use

plt.show(block=False)
plt.close('all')

Delete all rows in an HTML table

this would work iteration deletetion in HTML table in native

document.querySelectorAll("table tbody tr").forEach(function(e){e.remove()})

How to call JavaScript function instead of href in HTML

That syntax should work OK, but you can try this alternative.

<a href="javascript:void(0);" onclick="ShowOld(2367,146986,2);">

or

<a href="javascript:ShowOld(2367, 146986, 2);">

UPDATED ANSWER FOR STRING VALUES

If you are passing strings, use single quotes for your function's parameters

<a href="javascript:ShowOld('foo', 146986, 'bar');">

Adding onClick event dynamically using jQuery

Try below approach,

$('#bfCaptchaEntry').on('click', myfunction);

or in case jQuery is not an absolute necessaity then try below,

document.getElementById('bfCaptchaEntry').onclick = myfunction;

However the above method has few drawbacks as it set onclick as a property rather than being registered as handler...

Read more on this post https://stackoverflow.com/a/6348597/297641

Order columns through Bootstrap4

You can do two different container one with mobile order and hide on desktop screen, another with desktop order and hide on mobile screen

Error: EACCES: permission denied, access '/usr/local/lib/node_modules'

I was able to fix the issue using the following in mac.

sudo npm install -g @aws-amplify/cli --unsafe-perm=true

Socket.io + Node.js Cross-Origin Request Blocked

I just wanted to say that after trying a bunch of things, what fixed my CORS problem was simply using an older version of socket.io (version 2.2.0). My package.json file now looks like this:

{
  "name": "current-project",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "devStart": "nodemon server.js"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "socket.io": "^2.2.0"
  },
  "devDependencies": {
    "nodemon": "^1.19.0"
  }
}


If you execute npm install with this, you may find that the CORS problem goes away when trying to use socket.io. At least it worked for me.

What is the use of GO in SQL Server Management Studio & Transact SQL?

The GO command isn't a Transact-SQL statement, but a special command recognized by several MS utilities including SQL Server Management Studio code editor.

The GO command is used to group SQL commands into batches which are sent to the server together. The commands included in the batch, that is, the set of commands since the last GO command or the start of the session, must be logically consistent. For example, you can't define a variable in one batch and then use it in another since the scope of the variable is limited to the batch in which it's defined.

For more information, see http://msdn.microsoft.com/en-us/library/ms188037.aspx.

Create a menu Bar in WPF?

<StackPanel VerticalAlignment="Top">
    <Menu Width="Auto" Height="20">
        <MenuItem Header="_File">
            <MenuItem x:Name="AppExit" Header="E_xit" HorizontalAlignment="Left" Width="140" Click="AppExit_Click"/>
        </MenuItem>
        <MenuItem Header="_Tools">
            <MenuItem x:Name="Options" Header="_Options" HorizontalAlignment="Left" Width="140"/>
        </MenuItem>
        <MenuItem Header="_Help">
            <MenuItem x:Name="About" Header="&amp;About" HorizontalAlignment="Left" Width="140"/>
        </MenuItem>
    </Menu>
    <Label Content="Label"/>
</StackPanel>

Send Email to multiple Recipients with MailMessage?

As suggested by Adam Miller in the comments, I'll add another solution.

The MailMessage(String from, String to) constructor accepts a comma separated list of addresses. So if you happen to have already a comma (',') separated list, the usage is as simple as:

MailMessage Msg = new MailMessage(fromMail, addresses);

In this particular case, we can replace the ';' for ',' and still make use of the constructor.

MailMessage Msg = new MailMessage(fromMail, addresses.replace(";", ","));

Whether you prefer this or the accepted answer it's up to you. Arguably the loop makes the intent clearer, but this is shorter and not obscure. But should you already have a comma separated list, I think this is the way to go.

Inverse of a matrix using numpy

Another way to do this is to use the numpy matrix class (rather than a numpy array) and the I attribute. For example:

>>> m = np.matrix([[2,3],[4,5]])
>>> m.I
matrix([[-2.5,  1.5],
       [ 2. , -1. ]])

How can I send the "&" (ampersand) character via AJAX?

You can use encodeURIComponent().

It will escape all the characters that cannot occur verbatim in URLs:

var wysiwyg_clean = encodeURIComponent(wysiwyg);

In this example, the ampersand character & will be replaced by the escape sequence %26, which is valid in URLs.

How to show particular image as thumbnail while implementing share on Facebook?

I see that all the answers provided are correct. However, one important detail was overlooked: The size of the image MUST be at least 200 X 200 px, otherwise Facebook will substitute the thumbnail with the first available image that meets the criteria on the page. Another fact is that the minimum required is to include the 3 metas that Facebook requires for the og:image to take effect:

<meta property="og:title" content="Title of the page" />
<!-- NEXT LINE Even if page is dynamically generated and URL contains query parameters -->
<meta property="og:url" content="http://yoursite.com" />
<meta property="og:image" content="http://convertaholics.com/convertaholics-og.png" />

Debug your page with Facebook debugger and fix all the warnings and it should work like a charm! https://developers.facebook.com/tools/debug

changing the owner of folder in linux

Use chown to change ownership and chmod to change rights.

use the -R option to apply the rights for all files inside of a directory too.

Note that both these commands just work for directories too. The -R option makes them also change the permissions for all files and directories inside of the directory.

For example

sudo chown -R username:group directory

will change ownership (both user and group) of all files and directories inside of directory and directory itself.

sudo chown username:group directory

will only change the permission of the folder directory but will leave the files and folders inside the directory alone.

you need to use sudo to change the ownership from root to yourself.

Edit:

Note that if you use chown user: file (Note the left-out group), it will use the default group for that user.

Also You can change the group ownership of a file or directory with the command:

chgrp group_name file/directory_name

You must be a member of the group to which you are changing ownership to.

You can find group of file as follows

# ls -l file
-rw-r--r-- 1 root family 0 2012-05-22 20:03 file

# chown sujit:friends file

User 500 is just a normal user. Typically user 500 was the first user on the system, recent changes (to /etc/login.defs) has altered the minimum user id to 1000 in many distributions, so typically 1000 is now the first (non root) user.

What you may be seeing is a system which has been upgraded from the old state to the new state and still has some processes knocking about on uid 500. You can likely change it by first checking if your distro should indeed now use 1000, and if so alter the login.defs file yourself, the renumber the user account in /etc/passwd and chown/chgrp all their files, usually in /home/, then reboot.

But in answer to your question, no, you should not really be worried about this in all likelihood. It'll be showing as "500" instead of a username because o user in /etc/passwd has a uid set of 500, that's all.

Also you can show your current numbers using id i'm willing to bet it comes back as 1000 for you.

Hadoop cluster setup - java.net.ConnectException: Connection refused

In /etc/hosts:

  1. Add this line:

your-ip-address your-host-name

example: 192.168.1.8 master

In /etc/hosts:

  1. Delete the line with 127.0.1.1 (This will cause loopback)

  2. In your core-site, change localhost to your-ip or your-hostname

Now, restart the cluster.

How to initialize private static members in C++?

For future viewers of this question, I want to point out that you should avoid what monkey0506 is suggesting.

Header files are for declarations.

Header files get compiled once for every .cpp file that directly or indirectly #includes them, and code outside of any function is run at program initialization, before main().

By putting: foo::i = VALUE; into the header, foo:i will be assigned the value VALUE (whatever that is) for every .cpp file, and these assignments will happen in an indeterminate order (determined by the linker) before main() is run.

What if we #define VALUE to be a different number in one of our .cpp files? It will compile fine and we will have no way of knowing which one wins until we run the program.

Never put executed code into a header for the same reason that you never #include a .cpp file.

include guards (which I agree you should always use) protect you from something different: the same header being indirectly #included multiple times while compiling a single .cpp file

Using "super" in C++

I don't recall seeing this before, but at first glance I like it. As Ferruccio notes, it doesn't work well in the face of MI, but MI is more the exception than the rule and there's nothing that says something needs to be usable everywhere to be useful.

Change content of div - jQuery

There are 2 jQuery functions that you'll want to use here.

1) click. This will take an anonymous function as it's sole parameter, and will execute it when the element is clicked.

2) html. This will take an html string as it's sole parameter, and will replace the contents of your element with the html provided.

So, in your case, you'll want to do the following:

$('#content-container a').click(function(e){
    $(this).parent().html('<a href="#">I\'m a new link</a>');
    e.preventDefault();
});

If you only want to add content to your div, rather than replacing everything in it, you should use append:

$('#content-container a').click(function(e){
    $(this).parent().append('<a href="#">I\'m a new link</a>');
    e.preventDefault();
});

If you want the new added links to also add new content when clicked, you should use event delegation:

$('#content-container').on('click', 'a', function(e){
    $(this).parent().append('<a href="#">I\'m a new link</a>');
    e.preventDefault();
});

Finding first blank row, then writing to it

Very old thread but a simpler take :)

Sub firstBlank(c) 'as letter
    MsgBox (c & Split(Range(c & ":" & c).Find("", LookIn:=xlValues).address, "$")(2))
End Sub
Sub firstBlank(c) 'as number
    cLet = Split(Cells(1, c).address, "$")(1)
    MsgBox (cLet & Split(Range(cLet & ":" & cLet).Find("", LookIn:=xlValues).address, "$")(2))
End Sub

Use 'import module' or 'from module import'?

I was answering a similar question post but the poster deleted it before i could post. Here is one example to illustrate the differences.

Python libraries may have one or more files (modules). For exmaples,

package1
  |-- __init__.py

or

package2
  |-- __init__.py
  |-- module1.py
  |-- module2.py

We can define python functions or classes inside any of the files based design requirements.

Let's define

  1. func1() in __init__.py under mylibrary1, and
  2. foo() in module2.py under mylibrary2.

We can access func1() using one of these methods

import package1

package1.func1()

or

import package1 as my

my.func1()

or

from package1 import func1

func1()

or

from package1 import *

func1()

We can use one of these methods to access foo():

import package2.module2

package2.module2.foo()

or

import package2.module2 as mod2

mod2.foo()

or

from package2 import module2

module2.foo()

or

from package2 import module2 as mod2

mod2.foo()

or

from package2.module2 import *

foo()

Matplotlib: Specify format of floats for tick labels

The answer above is probably the correct way to do it, but didn't work for me.

The hacky way that solved it for me was the following:

ax = <whatever your plot is> 
# get the current labels 
labels = [item.get_text() for item in ax.get_xticklabels()]
# Beat them into submission and set them back again
ax.set_xticklabels([str(round(float(label), 2)) for label in labels])
# Show the plot, and go home to family 
plt.show()

Scanner method to get a char

Java's Scanner class does not have a built in method to read from a Scanner character-by-character.

http://java.sun.com/javase/6/docs/api/java/util/Scanner.html

However, it should still be possible to fetch individual characters from the Scanner as follows:

Scanner sc:

char c = sc.findInLine(".").charAt(0);

And you could use it to fetch each character in your scanner like this:

while(sc.hasNext()){
    char c = sc.findInLine(".").charAt(0);
    System.out.println(c); //to print out every char in the scanner
}

The findInLine() method searches through your scanner and returns the first String that matches the regular expression you give it.

JavaScript Extending Class

Try this:

Function.prototype.extends = function(parent) {
  this.prototype = Object.create(parent.prototype);
};

Monkey.extends(Monster);
function Monkey() {
  Monster.apply(this, arguments); // call super
}

Edit: I put a quick demo here http://jsbin.com/anekew/1/edit. Note that extends is a reserved word in JS and you may get warnings when linting your code, you can simply name it inherits, that's what I usually do.

With this helper in place and using an object props as only parameter, inheritance in JS becomes a bit simpler:

Function.prototype.inherits = function(parent) {
  this.prototype = Object.create(parent.prototype);
};

function Monster(props) {
  this.health = props.health || 100;
}

Monster.prototype = {
  growl: function() {
    return 'Grrrrr';
  }
};

Monkey.inherits(Monster);
function Monkey() {
  Monster.apply(this, arguments);
}

var monkey = new Monkey({ health: 200 });

console.log(monkey.health); //=> 200
console.log(monkey.growl()); //=> "Grrrr"

Call a function on click event in Angular 2

The line in your controller code, which reads $scope.myFunc={ should be $scope.myFunc = function() { the function() part is important to indicate, it is a function!

The updated controller code would be

app.controller('myCtrl',['$scope',function($cope){
    $scope.myFunc = function() {
    console.log("function called");
  };
}]);

How to set a Postgresql default value datestamp like 'YYYYMM'?

Right. Better to use a function:

CREATE OR REPLACE FUNCTION yyyymm() RETURNS text
    LANGUAGE 'plpgsql' AS $$
DECLARE
    retval text;
    m integer;
BEGIN
    retval := EXTRACT(year from current_timestamp);
    m := EXTRACT(month from current_timestamp);
    IF m < 10 THEN retval := retval || '0'; END IF;
    RETURN retval || m;
END $$;

SELECT yyyymm();

DROP TABLE foo;
CREATE TABLE foo (
    key             int PRIMARY KEY,
    colname text DEFAULT yyyymm()
    );
INSERT INTO foo (key) VALUES (0);
SELECT * FROM FOO;

This gives me

 key | colname 
-----+---------
   0 | 200905

Make sure you run createlang plpgsql from the Unix command line, if necessary.

How to get the mouse position without events (without moving the mouse)?

Edit 2020: This does not work any more. It seems so, that the browser vendors patched this out. Because the most browsers rely on chromium, it might be in its core.

Old answer: You can also hook mouseenter (this event is fired after page reload, when the mousecursor is inside the page). Extending Corrupted's code should do the trick:

_x000D_
_x000D_
var x = null;_x000D_
var y = null;_x000D_
    _x000D_
document.addEventListener('mousemove', onMouseUpdate, false);_x000D_
document.addEventListener('mouseenter', onMouseUpdate, false);_x000D_
    _x000D_
function onMouseUpdate(e) {_x000D_
  x = e.pageX;_x000D_
  y = e.pageY;_x000D_
  console.log(x, y);_x000D_
}_x000D_
_x000D_
function getMouseX() {_x000D_
  return x;_x000D_
}_x000D_
_x000D_
function getMouseY() {_x000D_
  return y;_x000D_
}
_x000D_
_x000D_
_x000D_

You can also set x and y to null on mouseleave-event. So you can check if the user is on your page with it's cursor.

Capturing browser logs with Selenium WebDriver using Java

A less elegant solution is taking the log 'manually' from the user data dir:

  1. Set the user data dir to a fixed place:

    options = new ChromeOptions();
    capabilities = DesiredCapabilities.chrome();
    options.addArguments("user-data-dir=/your_path/");
    capabilities.setCapability(ChromeOptions.CAPABILITY, options);
    
  2. Get the text from the log file chrome_debug.log located in the path you've entered above.

I use this method since RemoteWebDriver had problems getting the console logs remotely. If you run your test locally that can be easy to retrieve.

How can I convert IPV6 address to IPV4 address?

Here is the code you are looking for in javascript. Well you know you can't convert all of the ipv6 addresses

<script>
function parseIp6(str)
{
  //init
  var ar=new Array;
  for(var i=0;i<8;i++)ar[i]=0;
  //check for trivial IPs
  if(str=="::")return ar;
  //parse
  var sar=str.split(':');
  var slen=sar.length;
  if(slen>8)slen=8;
  var j=0;
  for(var i=0;i<slen;i++){
    //this is a "::", switch to end-run mode
    if(i && sar[i]==""){j=9-slen+i;continue;}
    ar[j]=parseInt("0x0"+sar[i]);
    j++;
  }

  return ar;
}
function ipcnvfrom6(ip6)
{
  var ip6=parseIp6(ip6);
  var ip4=(ip6[6]>>8)+"."+(ip6[6]&0xff)+"."+(ip6[7]>>8)+"."+(ip6[7]&0xff);
  return ip4;
}
alert(ipcnvfrom6("::C0A8:4A07"));
</script>

IllegalStateException: Can not perform this action after onSaveInstanceState with ViewPager

I have also experienced this issue and problem occurs every time when context of your FragmentActivity gets changed (e.g. Screen orientation is changed, etc.). So the best fix for it is to update context from your FragmentActivity.

How to iterate through a String

Using Guava (r07) you can do this:

for(char c : Lists.charactersOf(someString)) { ... }

This has the convenience of using foreach while not copying the string to a new array. Lists.charactersOf returns a view of the string as a List.

exit application when click button - iOS

exit(X), where X is a number (according to the doc) should work. But it is not recommended by Apple and won't be accepted by the AppStore. Why? Because of these guidelines (one of my app got rejected):

We found that your app includes a UI control for quitting the app. This is not in compliance with the iOS Human Interface Guidelines, as required by the App Store Review Guidelines.

Please refer to the attached screenshot/s for reference.

The iOS Human Interface Guidelines specify,

"Always Be Prepared to Stop iOS applications stop when people press the Home button to open a different application or use a device feature, such as the phone. In particular, people don’t tap an application close button or select Quit from a menu. To provide a good stopping experience, an iOS application should:

Save user data as soon as possible and as often as reasonable because an exit or terminate notification can arrive at any time.

Save the current state when stopping, at the finest level of detail possible so that people don’t lose their context when they start the application again. For example, if your app displays scrolling data, save the current scroll position."

> It would be appropriate to remove any mechanisms for quitting your app.

Plus, if you try to hide that function, it would be understood by the user as a crash.

Change key pair for ec2 instance

Once an instance has been started, there is no way to change the keypair associated with the instance at a meta data level, but you can change what ssh key you use to connect to the instance.

There is a startup process on most AMIs that downloads the public ssh key and installs it in a .ssh/authorized_keys file so that you can ssh in as that user using the corresponding private ssh key.

If you want to change what ssh key you use to access an instance, you will want to edit the authorized_keys file on the instance itself and convert to your new ssh public key.

The authorized_keys file is under the .ssh subdirectory under the home directory of the user you are logging in as. Depending on the AMI you are running, it might be in one of:

/home/ec2-user/.ssh/authorized_keys
/home/ubuntu/.ssh/authorized_keys
/root/.ssh/authorized_keys

After editing an authorized_keys file, always use a different terminal to confirm that you are able to ssh in to the instance before you disconnect from the session you are using to edit the file. You don't want to make a mistake and lock yourself out of the instance entirely.

While you're thinking about ssh keypairs on EC2, I recommend uploading your own personal ssh public key to EC2 instead of having Amazon generate the keypair for you.

Here's an article I wrote about this:

Uploading Personal ssh Keys to Amazon EC2
http://alestic.com/2010/10/ec2-ssh-keys

This would only apply to new instances you run.

SSRS Query execution failed for dataset

I just dealt with this same issue. Make sure your query lists the full source name, using no shortcuts. Visual Studio can recognize the shortcuts, but your reporting services application may not be able to recognize which tables your data should be coming from. Hope that helps.

Calculating difference between two timestamps in Oracle in milliseconds

Easier solution:

SELECT numtodsinterval(date1-date2,'day') time_difference from dates;

For timestamps:

SELECT (extract(DAY FROM time2-time1)*24*60*60)+ 
(extract(HOUR FROM time2-time1)*60*60)+
(extract(MINUTE FROM time2-time1)*60)+
extract(SECOND FROM time2-time1)
into diff FROM dual;

RETURN diff;

phpMyAdmin - The MySQL Extension is Missing

In my case I had to install the extension:

yum install php php-mysql httpd

and then restart apache:

service httpd restart

That solved the problem.

Learning Regular Expressions

The most important part is the concepts. Once you understand how the building blocks work, differences in syntax amount to little more than mild dialects. A layer on top of your regular expression engine's syntax is the syntax of the programming language you're using. Languages such as Perl remove most of this complication, but you'll have to keep in mind other considerations if you're using regular expressions in a C program.

If you think of regular expressions as building blocks that you can mix and match as you please, it helps you learn how to write and debug your own patterns but also how to understand patterns written by others.

Start simple

Conceptually, the simplest regular expressions are literal characters. The pattern N matches the character 'N'.

Regular expressions next to each other match sequences. For example, the pattern Nick matches the sequence 'N' followed by 'i' followed by 'c' followed by 'k'.

If you've ever used grep on Unix—even if only to search for ordinary looking strings—you've already been using regular expressions! (The re in grep refers to regular expressions.)

Order from the menu

Adding just a little complexity, you can match either 'Nick' or 'nick' with the pattern [Nn]ick. The part in square brackets is a character class, which means it matches exactly one of the enclosed characters. You can also use ranges in character classes, so [a-c] matches either 'a' or 'b' or 'c'.

The pattern . is special: rather than matching a literal dot only, it matches any character†. It's the same conceptually as the really big character class [-.?+%$A-Za-z0-9...].

Think of character classes as menus: pick just one.

Helpful shortcuts

Using . can save you lots of typing, and there are other shortcuts for common patterns. Say you want to match a digit: one way to write that is [0-9]. Digits are a frequent match target, so you could instead use the shortcut \d. Others are \s (whitespace) and \w (word characters: alphanumerics or underscore).

The uppercased variants are their complements, so \S matches any non-whitespace character, for example.

Once is not enough

From there, you can repeat parts of your pattern with quantifiers. For example, the pattern ab?c matches 'abc' or 'ac' because the ? quantifier makes the subpattern it modifies optional. Other quantifiers are

  • * (zero or more times)
  • + (one or more times)
  • {n} (exactly n times)
  • {n,} (at least n times)
  • {n,m} (at least n times but no more than m times)

Putting some of these blocks together, the pattern [Nn]*ick matches all of

  • ick
  • Nick
  • nick
  • Nnick
  • nNick
  • nnick
  • (and so on)

The first match demonstrates an important lesson: * always succeeds! Any pattern can match zero times.

A few other useful examples:

  • [0-9]+ (and its equivalent \d+) matches any non-negative integer
  • \d{4}-\d{2}-\d{2} matches dates formatted like 2019-01-01

Grouping

A quantifier modifies the pattern to its immediate left. You might expect 0abc+0 to match '0abc0', '0abcabc0', and so forth, but the pattern immediately to the left of the plus quantifier is c. This means 0abc+0 matches '0abc0', '0abcc0', '0abccc0', and so on.

To match one or more sequences of 'abc' with zeros on the ends, use 0(abc)+0. The parentheses denote a subpattern that can be quantified as a unit. It's also common for regular expression engines to save or "capture" the portion of the input text that matches a parenthesized group. Extracting bits this way is much more flexible and less error-prone than counting indices and substr.

Alternation

Earlier, we saw one way to match either 'Nick' or 'nick'. Another is with alternation as in Nick|nick. Remember that alternation includes everything to its left and everything to its right. Use grouping parentheses to limit the scope of |, e.g., (Nick|nick).

For another example, you could equivalently write [a-c] as a|b|c, but this is likely to be suboptimal because many implementations assume alternatives will have lengths greater than 1.

Escaping

Although some characters match themselves, others have special meanings. The pattern \d+ doesn't match backslash followed by lowercase D followed by a plus sign: to get that, we'd use \\d\+. A backslash removes the special meaning from the following character.

Greediness

Regular expression quantifiers are greedy. This means they match as much text as they possibly can while allowing the entire pattern to match successfully.

For example, say the input is

"Hello," she said, "How are you?"

You might expect ".+" to match only 'Hello,' and will then be surprised when you see that it matched from 'Hello' all the way through 'you?'.

To switch from greedy to what you might think of as cautious, add an extra ? to the quantifier. Now you understand how \((.+?)\), the example from your question works. It matches the sequence of a literal left-parenthesis, followed by one or more characters, and terminated by a right-parenthesis.

If your input is '(123) (456)', then the first capture will be '123'. Non-greedy quantifiers want to allow the rest of the pattern to start matching as soon as possible.

(As to your confusion, I don't know of any regular-expression dialect where ((.+?)) would do the same thing. I suspect something got lost in transmission somewhere along the way.)

Anchors

Use the special pattern ^ to match only at the beginning of your input and $ to match only at the end. Making "bookends" with your patterns where you say, "I know what's at the front and back, but give me everything between" is a useful technique.

Say you want to match comments of the form

-- This is a comment --

you'd write ^--\s+(.+)\s+--$.

Build your own

Regular expressions are recursive, so now that you understand these basic rules, you can combine them however you like.

Tools for writing and debugging regexes:

Books

Free resources

Footnote

†: The statement above that . matches any character is a simplification for pedagogical purposes that is not strictly true. Dot matches any character except newline, "\n", but in practice you rarely expect a pattern such as .+ to cross a newline boundary. Perl regexes have a /s switch and Java Pattern.DOTALL, for example, to make . match any character at all. For languages that don't have such a feature, you can use something like [\s\S] to match "any whitespace or any non-whitespace", in other words anything.

How to get the containing form of an input?

If using jQuery and have a handle to any form element, you need to get(0) the element before using .form

var my_form = $('input[name=first_name]').get(0).form;

unexpected T_VARIABLE, expecting T_FUNCTION

Use access modifier before the member definition:

    private $connection;

As you cannot use function call in member definition in PHP, do it in constructor:

 public function __construct() {
      $this->connection = sqlite_open("[path]/data/users.sqlite", 0666);
 }

How to add external JS scripts to VueJS Components

Are you using one of the Webpack starter templates for vue (https://github.com/vuejs-templates/webpack)? It already comes set up with vue-loader (https://github.com/vuejs/vue-loader). If you're not using a starter template, you have to set up webpack and vue-loader.

You can then import your scripts to the relevant (single file) components. Before that, you have toexport from your scripts what you want to import to your components.

ES6 import:
- https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import
- http://exploringjs.com/es6/ch_modules.html

~Edit~
You can import from these wrappers:
- https://github.com/matfish2/vue-stripe
- https://github.com/khoanguyen96/vue-paypal-checkout

Convert list or numpy array of single element to float in python

Use numpy.asscalar to convert a numpy array / matrix a scalar value:

>>> a=numpy.array([[[[42]]]])
>>> numpy.asscalar(a)
42

The output data type is the same type returned by the input’s item method.

It has built in error-checking if there is more than an single element:

>>> a=numpy.array([1, 2])
>>> numpy.asscalar(a)

gives:

ValueError: can only convert an array of size 1 to a Python scalar

Note: the object passed to asscalar must respond to item, so passing a list or tuple won't work.

SHOW PROCESSLIST in MySQL command: sleep

"Sleep" state connections are most often created by code that maintains persistent connections to the database.

This could include either connection pools created by application frameworks, or client-side database administration tools.

As mentioned above in the comments, there is really no reason to worry about these connections... unless of course you have no idea where the connection is coming from.

(CAVEAT: If you had a long list of these kinds of connections, there might be a danger of running out of simultaneous connections.)

How can I remove a pytz timezone from a datetime object?

To remove a timezone (tzinfo) from a datetime object:

# dt_tz is a datetime.datetime object
dt = dt_tz.replace(tzinfo=None)

If you are using a library like arrow, then you can remove timezone by simply converting an arrow object to to a datetime object, then doing the same thing as the example above.

# <Arrow [2014-10-09T10:56:09.347444-07:00]>
arrowObj = arrow.get('2014-10-09T10:56:09.347444-07:00')

# datetime.datetime(2014, 10, 9, 10, 56, 9, 347444, tzinfo=tzoffset(None, -25200))
tmpDatetime = arrowObj.datetime

# datetime.datetime(2014, 10, 9, 10, 56, 9, 347444)
tmpDatetime = tmpDatetime.replace(tzinfo=None)

Why would you do this? One example is that mysql does not support timezones with its DATETIME type. So using ORM's like sqlalchemy will simply remove the timezone when you give it a datetime.datetime object to insert into the database. The solution is to convert your datetime.datetime object to UTC (so everything in your database is UTC since it can't specify timezone) then either insert it into the database (where the timezone is removed anyway) or remove it yourself. Also note that you cannot compare datetime.datetime objects where one is timezone aware and another is timezone naive.

##############################################################################
# MySQL example! where MySQL doesn't support timezones with its DATETIME type!
##############################################################################

arrowObj = arrow.get('2014-10-09T10:56:09.347444-07:00')

arrowDt = arrowObj.to("utc").datetime

# inserts datetime.datetime(2014, 10, 9, 17, 56, 9, 347444, tzinfo=tzutc())
insertIntoMysqlDatabase(arrowDt)

# returns datetime.datetime(2014, 10, 9, 17, 56, 9, 347444)
dbDatetimeNoTz = getFromMysqlDatabase()

# cannot compare timzeone aware and timezone naive
dbDatetimeNoTz == arrowDt # False, or TypeError on python versions before 3.3

# compare datetimes that are both aware or both naive work however
dbDatetimeNoTz == arrowDt.replace(tzinfo=None) # True

Creating a generic method in C#

What about this? Change the return type from T to Nullable<T>

public static Nullable<T> GetQueryString<T>(string key) where T : struct, IConvertible
        {
            T result = default(T);

            if (String.IsNullOrEmpty(HttpContext.Current.Request.QueryString[key]) == false)
            {
                string value = HttpContext.Current.Request.QueryString[key];

                try
                {
                    result = (T)Convert.ChangeType(value, typeof(T));  
                }
                catch
                {
                    //Could not convert.  Pass back default value...
                    result = default(T);
                }
            }

            return result;
        }

log4j vs logback

Not exactly answering your question, but if you could move away from your self-made wrapper then there is Simple Logging Facade for Java (SLF4J) which Hibernate has now switched to (instead of commons logging).

SLF4J suffers from none of the class loader problems or memory leaks observed with Jakarta Commons Logging (JCL).

SLF4J supports JDK logging, log4j and logback. So then it should be fairly easy to switch from log4j to logback when the time is right.

Edit: Aplogies that I hadn't made myself clear. I was suggesting using SLF4J to isolate yourself from having to make a hard choice between log4j or logback.

Animated GIF in IE stopping

A very easy way is to use jQuery and SimpleModal plugin. Then when I need to show my "loading" gif on submit, I do:

$('*').css('cursor','wait');
$.modal("<table style='white-space: nowrap'><tr><td style='white-space: nowrap'><b>Please wait...</b></td><td><img alt='Please wait' src='loader.gif' /></td></tr></table>", {escClose:false} );

If else on WHERE clause

try this ,hope it helps

select user_display_image as user_image,
user_display_name as user_name,
invitee_phone,
(
 CASE 
    WHEN invitee_status=1 THEN "attending" 
    WHEN invitee_status=2 THEN "unsure" 
    WHEN invitee_status=3 THEN "declined" 
    WHEN invitee_status=0 THEN "notreviwed" END
) AS  invitee_status
 FROM your_tbl

Centering a background image, using CSS

background-position: center center;

doesn't work for me without...

background-attachment: fixed;

using both centered my image on x and y axis

background-position: center center;
background-repeat: no-repeat;
background-attachment: fixed;

How can I save application settings in a Windows Forms application?

If you are planning on saving to a file within the same directory as your executable, here's a nice solution that uses the JSON format:

using System;
using System.IO;
using System.Web.Script.Serialization;

namespace MiscConsole
{
    class Program
    {
        static void Main(string[] args)
        {
            MySettings settings = MySettings.Load();
            Console.WriteLine("Current value of 'myInteger': " + settings.myInteger);
            Console.WriteLine("Incrementing 'myInteger'...");
            settings.myInteger++;
            Console.WriteLine("Saving settings...");
            settings.Save();
            Console.WriteLine("Done.");
            Console.ReadKey();
        }

        class MySettings : AppSettings<MySettings>
        {
            public string myString = "Hello World";
            public int myInteger = 1;
        }
    }

    public class AppSettings<T> where T : new()
    {
        private const string DEFAULT_FILENAME = "settings.json";

        public void Save(string fileName = DEFAULT_FILENAME)
        {
            File.WriteAllText(fileName, (new JavaScriptSerializer()).Serialize(this));
        }

        public static void Save(T pSettings, string fileName = DEFAULT_FILENAME)
        {
            File.WriteAllText(fileName, (new JavaScriptSerializer()).Serialize(pSettings));
        }

        public static T Load(string fileName = DEFAULT_FILENAME)
        {
            T t = new T();
            if(File.Exists(fileName))
                t = (new JavaScriptSerializer()).Deserialize<T>(File.ReadAllText(fileName));
            return t;
        }
    }
}

How to find common elements from multiple vectors?

intersect_all <- function(a,b,...){
  all_data <- c(a,b,...)
  require(plyr)
  count_data<- length(list(a,b,...))
  freq_dist <- count(all_data)
  intersect_data <- freq_dist[which(freq_dist$freq==count_data),"x"]
  intersect_data
}


intersect_all(a,b,c)

UPDATE EDIT A simpler code

intersect_all <- function(a,b,...){
  Reduce(intersect, list(a,b,...))
}

intersect_all(a,b,c)

How do you make Vim unhighlight what you searched for?

There is hlsearch and nohlsearch. :help hlsearch will provide more information.

If you want to bind F12 to toggle it on/off you can use this:

map     <F12>   :nohlsearch<CR>
imap    <F12>   <ESC>:nohlsearch<CR>i
vmap    <F12>   <ESC>:nohlsearch<CR>gv

How to pass arguments to entrypoint in docker-compose.yml

I was facing the same issue with jenkins ssh slave 'jenkinsci/ssh-slave'. However, my case was a bit complicated because it was necessary to pass an argument which contained spaces. I've managed to do it like below (entrypoint in dockerfile is in exec form):

command: ["some argument with space which should be treated as one"]

Explain the "setUp" and "tearDown" Python methods used in test cases

You can use these to factor out code common to all tests in the test suite.

If you have a lot of repeated code in your tests, you can make them shorter by moving this code to setUp/tearDown.

You might use this for creating test data (e.g. setting up fakes/mocks), or stubbing out functions with fakes.

If you're doing integration testing, you can use check environmental pre-conditions in setUp, and skip the test if something isn't set up properly.

For example:

class TurretTest(unittest.TestCase):

    def setUp(self):
        self.turret_factory = TurretFactory()
        self.turret = self.turret_factory.CreateTurret()

    def test_turret_is_on_by_default(self):
        self.assertEquals(True, self.turret.is_on())

    def test_turret_turns_can_be_turned_off(self):
        self.turret.turn_off()
        self.assertEquals(False, self.turret.is_on())

Where are static variables stored in C and C++?

Data declared in a compilation unit will go into the .BSS or the .Data of that files output. Initialised data in BSS, uninitalised in DATA.

The difference between static and global data comes in the inclusion of symbol information in the file. Compilers tend to include the symbol information but only mark the global information as such.

The linker respects this information. The symbol information for the static variables is either discarded or mangled so that static variables can still be referenced in some way (with debug or symbol options). In neither case can the compilation units gets affected as the linker resolves local references first.

How do I enumerate through a JObject?

JObjects can be enumerated via JProperty objects by casting it to a JToken:

foreach (JProperty x in (JToken)obj) { // if 'obj' is a JObject
    string name = x.Name;
    JToken value = x.Value;
}

If you have a nested JObject inside of another JObject, you don't need to cast because the accessor will return a JToken:

foreach (JProperty x in obj["otherObject"]) { // Where 'obj' and 'obj["otherObject"]' are both JObjects
    string name = x.Name;
    JToken value = x.Value;
}

Turning a Comma Separated string into individual rows

As of Feb 2016 - see the TALLY Table Example - very likely to outperform my TVF below, from Feb 2014. Keeping original post below for posterity:


Too much repeated code for my liking in the above examples. And I dislike the performance of CTEs and XML. Also, an explicit Id so that consumers that are order specific can specify an ORDER BY clause.

CREATE FUNCTION dbo.Split
(
    @Line nvarchar(MAX),
    @SplitOn nvarchar(5) = ','
)
RETURNS @RtnValue table
(
    Id INT NOT NULL IDENTITY(1,1) PRIMARY KEY CLUSTERED,
    Data nvarchar(100) NOT NULL
)
AS
BEGIN
    IF @Line IS NULL RETURN

    DECLARE @split_on_len INT = LEN(@SplitOn)
    DECLARE @start_at INT = 1
    DECLARE @end_at INT
    DECLARE @data_len INT

    WHILE 1=1
    BEGIN
        SET @end_at = CHARINDEX(@SplitOn,@Line,@start_at)
        SET @data_len = CASE @end_at WHEN 0 THEN LEN(@Line) ELSE @end_at-@start_at END
        INSERT INTO @RtnValue (data) VALUES( SUBSTRING(@Line,@start_at,@data_len) );
        IF @end_at = 0 BREAK;
        SET @start_at = @end_at + @split_on_len
    END

    RETURN
END

Is there a way to use use text as the background with CSS?

Using pure CSS:

(But use this in rare occasions, because HTML method is PREFERRED WAY).

_x000D_
_x000D_
.container{_x000D_
 position:relative;_x000D_
}_x000D_
.container::before{ _x000D_
 content:"";_x000D_
 width: 100%; height: 100%; position: absolute; background: black; opacity: 0.3; z-index: 1;  top: 0;   left: 0;_x000D_
 background: black;_x000D_
}_x000D_
.container::after{ _x000D_
 content: "Your Text"; position: absolute; top: 0; left: 0; bottom: 0; right: 0; z-index: 3; overflow: hidden; font-size: 2em; color: red;    text-align: center; text-shadow: 0px 0px 5px black; background: #0a0a0a8c; padding: 5px;_x000D_
 animation-name: blinking;_x000D_
 animation-duration: 1s;_x000D_
 animation-iteration-count: infinite;_x000D_
 animation-direction: alternate;_x000D_
}_x000D_
@keyframes blinking {_x000D_
 0% {opacity: 0;}_x000D_
 100% {opacity: 1;}_x000D_
}
_x000D_
<div class="container">here is main content, text , <br/> images and other page details</div>
_x000D_
_x000D_
_x000D_

How to measure time elapsed on Javascript?

var seconds = 0;
setInterval(function () {
  seconds++;
}, 1000);

There you go, now you have a variable counting seconds elapsed. Since I don't know the context, you'll have to decide whether you want to attach that variable to an object or make it global.

Set interval is simply a function that takes a function as it's first parameter and a number of milliseconds to repeat the function as it's second parameter.

You could also solve this by saving and comparing times.

EDIT: This answer will provide very inconsistent results due to things such as the event loop and the way browsers may choose to pause or delay processing when a page is in a background tab. I strongly recommend using the accepted answer.

IE6/IE7 css border on select element

Using ONLY css is impossbile. In fact, all form elements are impossible to customize to look in the same way on all browsers only with css. You can try niceforms though ;)

How do I perform query filtering in django templates

I run into this problem on a regular basis and often use the "add a method" solution. However, there are definitely cases where "add a method" or "compute it in the view" don't work (or don't work well). E.g. when you are caching template fragments and need some non-trivial DB computation to produce it. You don't want to do the DB work unless you need to, but you won't know if you need to until you are deep in the template logic.

Some other possible solutions:

  1. Use the {% expr <expression> as <var_name> %} template tag found at http://www.djangosnippets.org/snippets/9/ The expression is any legal Python expression with your template's Context as your local scope.

  2. Change your template processor. Jinja2 (http://jinja.pocoo.org/2/) has syntax that is almost identical to the Django template language, but with full Python power available. It's also faster. You can do this wholesale, or you might limit its use to templates that you are working on, but use Django's "safer" templates for designer-maintained pages.

Why use Redux over Facebook Flux?

I worked quite a long time with Flux and now quite a long time using Redux. As Dan pointed out both architectures are not so different. The thing is that Redux makes the things simpler and cleaner. It teaches you a couple of things on top of Flux. Like for example Flux is a perfect example of one-direction data flow. Separation of concerns where we have data, its manipulations and view layer separated. In Redux we have the same things but we also learn about immutability and pure functions.

Alternative to header("Content-type: text/xml");

Now I see what you are doing. You cannot send output to the screen then change the headers. If you are trying to create an XML file of map marker and download them to display, they should be in separate files.

Take this

<?php
require("database.php");
function parseToXML($htmlStr)
{
$xmlStr=str_replace('<','&lt;',$htmlStr);
$xmlStr=str_replace('>','&gt;',$xmlStr);
$xmlStr=str_replace('"','&quot;',$xmlStr);
$xmlStr=str_replace("'",'&#39;',$xmlStr);
$xmlStr=str_replace("&",'&amp;',$xmlStr);
return $xmlStr;
}
// Opens a connection to a MySQL server
$connection=mysql_connect (localhost, $username, $password);
if (!$connection) {
  die('Not connected : ' . mysql_error());
}
// Set the active MySQL database
$db_selected = mysql_select_db($database, $connection);
if (!$db_selected) {
  die ('Can\'t use db : ' . mysql_error());
}
// Select all the rows in the markers table
$query = "SELECT * FROM markers WHERE 1";
$result = mysql_query($query);
if (!$result) {
  die('Invalid query: ' . mysql_error());
}
header("Content-type: text/xml");
// Start XML file, echo parent node
echo '<markers>';
// Iterate through the rows, printing XML nodes for each
while ($row = @mysql_fetch_assoc($result)){
  // ADD TO XML DOCUMENT NODE
  echo '<marker ';
  echo 'name="' . parseToXML($row['name']) . '" ';
  echo 'address="' . parseToXML($row['address']) . '" ';
  echo 'lat="' . $row['lat'] . '" ';
  echo 'lng="' . $row['lng'] . '" ';
  echo 'type="' . $row['type'] . '" ';
  echo '/>';
}
// End XML file
echo '</markers>';
?>

and place it in phpsqlajax_genxml.php so your javascript can download the XML file. You are trying to do too many things in the same file.

How to import an existing directory into Eclipse?

I Using below simple way to create a project 1- First in a directory that desire to make it project, create a .project file with below contents:

<projectDescription>
    <name>Project-Name</name>
    <comment></comment>
    <projects>
    </projects>
    <buildSpec>
    </buildSpec>
    <natures>
    </natures>
</projectDescription>

2- Now instead of "Project-Name", write your project name, maybe current directory name

3- Now save this file to directory that desire to make that directory as project with name ".project" ( for save like this, use Notepad )

4- Now go to Eclips and open project and add your files to it.

Implementation difference between Aggregation and Composition in Java

A simple Composition program

public class Person {
    private double salary;
    private String name;
    private Birthday bday;

    public Person(int y,int m,int d,String name){
        bday=new Birthday(y, m, d);
        this.name=name;
    }


    public double getSalary() {
        return salary;
    }

    public String getName() {
        return name;
    }

    public Birthday getBday() {
        return bday;
    }

    ///////////////////////////////inner class///////////////////////
    private class Birthday{
        int year,month,day;

        public Birthday(int y,int m,int d){
            year=y;
            month=m;
            day=d;
        }

        public String toString(){
           return String.format("%s-%s-%s", year,month,day);

        }
    }

    //////////////////////////////////////////////////////////////////

}
public class CompositionTst {

    public static void main(String[] args) {
        // TODO code application logic here
        Person person=new Person(2001, 11, 29, "Thilina");
        System.out.println("Name : "+person.getName());
        System.out.println("Birthday : "+person.getBday());

        //The below object cannot be created. A bithday cannot exixts without a Person 
        //Birthday bday=new Birthday(1988,11,10);

    }
}

Remove all child elements of a DOM node in JavaScript

Here's another approach:

function removeAllChildren(theParent){

    // Create the Range object
    var rangeObj = new Range();

    // Select all of theParent's children
    rangeObj.selectNodeContents(theParent);

    // Delete everything that is selected
    rangeObj.deleteContents();
}

RGB to hex and hex to RGB

My example =)

_x000D_
_x000D_
color: {_x000D_
            toHex: function(num){_x000D_
                var str = num.toString(16);_x000D_
                return (str.length<6?'#00'+str:'#'+str);_x000D_
            },_x000D_
            toNum: function(hex){_x000D_
                return parseInt(hex.replace('#',''), 16);_x000D_
            },_x000D_
            rgbToHex: function(color)_x000D_
            {_x000D_
                color = color.replace(/\s/g,"");_x000D_
                var aRGB = color.match(/^rgb\((\d{1,3}[%]?),(\d{1,3}[%]?),(\d{1,3}[%]?)\)$/i);_x000D_
                if(aRGB)_x000D_
                {_x000D_
                    color = '';_x000D_
                    for (var i=1;  i<=3; i++) color += Math.round((aRGB[i][aRGB[i].length-1]=="%"?2.55:1)*parseInt(aRGB[i])).toString(16).replace(/^(.)$/,'0$1');_x000D_
                }_x000D_
                else color = color.replace(/^#?([\da-f])([\da-f])([\da-f])$/i, '$1$1$2$2$3$3');_x000D_
                return '#'+color;_x000D_
            }
_x000D_
_x000D_
_x000D_

How do I install an R package from source?

In addition, you can build the binary package using the --binary option.

R CMD build --binary RJSONIO_0.2-3.tar.gz

ALTER TABLE add constraint

Omit the parenthesis:

ALTER TABLE User 
    ADD CONSTRAINT userProperties
    FOREIGN KEY(properties)
    REFERENCES Properties(ID)

Storing integer values as constants in Enum manner in java

You could store that const value in the enum like so. But why even use the const? Are you persisting the enum's?

public class SO3990319 {
   public static enum PAGE {
      SIGN_CREATE(1);
      private final int constValue;

      private PAGE(int constValue) {
         this.constValue = constValue;
      }

      public int constValue() {
         return constValue;
      }
   }

   public static void main(String[] args) {
      System.out.println("Name:    " + PAGE.SIGN_CREATE.name());
      System.out.println("Ordinal: " + PAGE.SIGN_CREATE.ordinal());
      System.out.println("Const:   " + PAGE.SIGN_CREATE.constValue());

      System.out.println("Enum: " + PAGE.valueOf("SIGN_CREATE"));
   }
}

Edit:

It depends on what you're using the int's for whether to use EnumMap or instance field.

Keep getting No 'Access-Control-Allow-Origin' error with XMLHttpRequest

In addition to your CORS issue, the server you are trying to access has HTTP basic authentication enabled. You can include credentials in your cross-domain request by specifying the credentials in the URL you pass to the XHR:

url = 'http://username:[email protected]/testpage'

Change the Textbox height?

for me, the best approach is remove border of the textbox, and place it inside a Panel, which can be customized as you like.

Best way to test for a variable's existence in PHP; isset() is clearly broken

Attempting to give an overview of the various discussions and answers:

There is no single answer to the question which can replace all the ways isset can be used. Some use cases are addressed by other functions, while others do not stand up to scrutiny, or have dubious value beyond code golf. Far from being "broken" or "inconsistent", other use cases demonstrate why isset's reaction to null is the logical behaviour.

Real use cases (with solutions)

1. Array keys

Arrays can be treated like collections of variables, with unset and isset treating them as though they were. However, since they can be iterated, counted, etc, a missing value is not the same as one whose value is null.

The answer in this case, is to use array_key_exists() instead of isset().

Since this is takes the array to check as a function argument, PHP will still raise "notices" if the array itself doesn't exist. In some cases, it can validly be argued that each dimension should have been initialised first, so the notice is doing its job. For other cases, a "recursive" array_key_exists function, which checked each dimension of the array in turn, would avoid this, but would basically be the same as @array_key_exists. It is also somewhat tangential to the handling of null values.

2. Object properties

In the traditional theory of "Object-Oriented Programming", encapsulation and polymorphism are key properties of objects; in a class-based OOP implementation like PHP's, the encapsulated properties are declared as part of the class definition, and given access levels (public, protected, or private).

However, PHP also allows you to dynamically add properties to an object, like you would keys to an array, and some people use class-less objects (technically, instances of the built in stdClass, which has no methods or private functionality) in a similar way to associative arrays. This leads to situations where a function may want to know if a particular property has been added to the object given to it.

As with array keys, a solution for checking object properties is included in the language, called, reasonably enough, property_exists.

Non-justifiable use cases, with discussion

3. register_globals, and other pollution of the global namespace

The register_globals feature added variables to the global scope whose names were determined by aspects of the HTTP request (GET and POST parameters, and cookies). This can lead to buggy and insecure code, which is why it has been disabled by default since PHP 4.2, released Aug 2000 and removed completely in PHP 5.4, released Mar 2012. However, it's possible that some systems are still running with this feature enabled or emulated. It's also possible to "pollute" the global namespace in other ways, using the global keyword, or $GLOBALS array.

Firstly, register_globals itself is unlikely to unexpectedly produce a null variable, since the GET, POST, and cookie values will always be strings (with '' still returning true from isset), and variables in the session should be entirely under the programmer's control.

Secondly, pollution of a variable with the value null is only an issue if this over-writes some previous initialization. "Over-writing" an uninitialized variable with null would only be problematic if code somewhere else was distinguishing between the two states, so on its own this possibility is an argument against making such a distinction.

4. get_defined_vars and compact

A few rarely-used functions in PHP, such as get_defined_vars and compact, allow you to treat variable names as though they were keys in an array. For global variables, the super-global array $GLOBALS allows similar access, and is more common. These methods of access will behave differently if a variable is not defined in the relevant scope.

Once you've decided to treat a set of variables as an array using one of these mechanisms, you can do all the same operations on it as on any normal array. Consequently, see 1.

Functionality that existed only to predict how these functions are about to behave (e.g. "will there be a key 'foo' in the array returned by get_defined_vars?") is superfluous, since you can simply run the function and find out with no ill effects.

4a. Variable variables ($$foo)

While not quite the same as functions which turn a set of variables into an associative array, most cases using "variable variables" ("assign to a variable named based on this other variable") can and should be changed to use an associative array instead.

A variable name, fundamentally, is the label given to a value by the programmer; if you're determining it at run-time, it's not really a label but a key in some key-value store. More practically, by not using an array, you are losing the ability to count, iterate, etc; it can also become impossible to have a variable "outside" the key-value store, since it might be over-written by $$foo.

Once changed to use an associative array, the code will be amenable to solution 1. Indirect object property access (e.g. $foo->$property_name) can be addressed with solution 2.

5. isset is so much easier to type than array_key_exists

I'm not sure this is really relevant, but yes, PHP's function names can be pretty long-winded and inconsistent sometimes. Apparently, pre-historic versions of PHP used a function name's length as a hash key, so Rasmus deliberately made up function names like htmlspecialchars so they would have an unusual number of characters...

Still, at least we're not writing Java, eh? ;)

6. Uninitialized variables have a type

The manual page on variable basics includes this statement:

Uninitialized variables have a default value of their type depending on the context in which they are used

I'm not sure whether there is some notion in the Zend Engine of "uninitialized but known type" or whether this is reading too much into the statement.

What is clear is that it makes no practical difference to their behaviour, since the behaviours described on that page for uninitialized variables are identical to the behaviour of a variable whose value is null. To pick one example, both $a and $b in this code will end up as the integer 42:

unset($a);
$a += 42;

$b = null;
$b += 42;

(The first will raise a notice about an undeclared variable, in an attempt to make you write better code, but it won't make any difference to how the code actually runs.)

99. Detecting if a function has run

(Keeping this one last, as it's much longer than the others. Maybe I'll edit it down later...)

Consider the following code:

$test_value = 'hello';
foreach ( $list_of_things as $thing ) {
    if ( some_test($thing, $test_value) ) {
        $result = some_function($thing);
    }
}
if ( isset($result) ) {
    echo 'The test passed at least once!';
}

If some_function can return null, there's a possibility that the echo won't be reached even though some_test returned true. The programmer's intention was to detect when $result had never been set, but PHP does not allow them to do so.

However, there are other problems with this approach, which become clear if you add an outer loop:

foreach ( $list_of_tests as $test_value ) {
    // something's missing here...
    foreach ( $list_of_things as $thing ) {
        if ( some_test($thing, $test_value) ) {
            $result = some_function($thing);
        }
    }
    if ( isset($result) ) {
        echo 'The test passed at least once!';
    }
}

Because $result is never initialized explicitly, it will take on a value when the very first test passes, making it impossible to tell whether subsequent tests passed or not. This is actually an extremely common bug when variables aren't initialised properly.

To fix this, we need to do something on the line where I've commented that something's missing. The most obvious solution is to set $result to a "terminal value" that some_function can never return; if this is null, then the rest of the code will work fine. If there is no natural candidate for a terminal value because some_function has an extremely unpredictable return type (which is probably a bad sign in itself), then an additional boolean value, e.g. $found, could be used instead.

Thought experiment one: the very_null constant

PHP could theoretically provide a special constant - as well as null - for use as a terminal value here; presumably, it would be illegal to return this from a function, or it would be coerced to null, and the same would probably apply to passing it in as a function argument. That would make this very specific case slightly simpler, but as soon as you decided to re-factor the code - for instance, to put the inner loop into a separate function - it would become useless. If the constant could be passed between functions, you could not guarantee that some_function would not return it, so it would no longer be useful as a universal terminal value.

The argument for detecting uninitialised variables in this case boils down to the argument for that special constant: if you replace the comment with unset($result), and treat that differently from $result = null, you are introducing a "value" for $result that cannot be passed around, and can only be detected by specific built-in functions.

Thought experiment two: assignment counter

Another way of thinking about what the last if is asking is "has anything made an assignment to $result?" Rather than considering it to be a special value of $result, you could maybe think of this as "metadata" about the variable, a bit like Perl's "variable tainting". So rather than isset you might call it has_been_assigned_to, and rather than unset, reset_assignment_state.

But if so, why stop at a boolean? What if you want to know how many times the test passed; you could simply extend your metadata to an integer and have get_assignment_count and reset_assignment_count...

Obviously, adding such a feature would have a trade-off in complexity and performance of the language, so it would need to be carefully weighed against its expected usefulness. As with a very_null constant, it would be useful only in very narrow circumstances, and would be similarly resistant to re-factoring.

The hopefully-obvious question is why the PHP runtime engine should assume in advance that you want to keep track of such things, rather than leaving you to do it explicitly, using normal code.

How do I post button value to PHP?

Give them all a name that is the same

For example

<input type="button" value="a" name="btn" onclick="a" />
<input type="button" value="b" name="btn" onclick="b" />

Then in your php use:

$val = $_POST['btn']

Edit, as BalusC said; If you're not going to use onclick for doing any javascript (for example, sending the form) then get rid of it and use type="submit"

How do I remove the non-numeric character from a string in java?

One more approach for removing all non-numeric characters from a string:

String newString = oldString.replaceAll("[^0-9]", "");

How to truncate text in Angular2?

Truncate Pipe with optional params:

  • limit - string max length
  • completeWords - Flag to truncate at the nearest complete word, instead of character
  • ellipsis - appended trailing suffix

-

import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
  name: 'truncate'
})
export class TruncatePipe implements PipeTransform {
  transform(value: string, limit = 25, completeWords = false, ellipsis = '...') {
    if (completeWords) {
      limit = value.substr(0, limit).lastIndexOf(' ');
    }
    return value.length > limit ? value.substr(0, limit) + ellipsis : value;
  }
}

Don't forget to add a module entry.

@NgModule({
  declarations: [
    TruncatePipe
  ]
})
export class AppModule {}

Usage

Example String:

public longStr = 'A really long string that needs to be truncated';

Markup:

  <h1>{{longStr | truncate }}</h1> 
  <!-- Outputs: A really long string that... -->

  <h1>{{longStr | truncate : 12 }}</h1> 
  <!-- Outputs: A really lon... -->

  <h1>{{longStr | truncate : 12 : true }}</h1> 
  <!-- Outputs: A really... -->

  <h1>{{longStr | truncate : 12 : false : '***' }}</h1> 
  <!-- Outputs: A really lon*** -->

How to remove all ListBox items?

I made on this way, and work properly to me:

if (listview1.Items.Count > 0)
        {
            for (int a = listview1.Items.Count -1; a > 0 ; a--)
            {
                listview1.Items.RemoveAt(a);
            }
                listview1.Refresh();

        }

Explaining: using "Clear()" erases only the items, do not removes then from object, using RemoveAt() to removing an item of beginning position just realocate the others [if u remove item[0], item[1] turns into [0] triggering a new internal event], so removing from the ending no affect de others position, its a Stack behavior, this way we can Stack over all items, reseting the object.

JavaScript open in a new window, not tab

The key is the parameters :

If you provide Parameters [ Height="" , Width="" ] , then it will open in new windows.

If you DON'T provide Parameters , then it will open in new tab.

Tested in Chrome and Firefox

Should I Dispose() DataSet and DataTable?

Do you create the DataTables yourself? Because iterating through the children of any Object (as in DataSet.Tables) is usually not needed, as it's the job of the Parent to dispose all its child members.

Generally, the rule is: If you created it and it implements IDisposable, Dispose it. If you did NOT create it, then do NOT dispose it, that's the job of the parent object. But each object may have special rules, check the Documentation.

For .NET 3.5, it explicitly says "Dispose it when not using anymore", so that's what I would do.

what do these symbolic strings mean: %02d %01d?

% is a special character you put in format strings, for example in C language printf and scanf (and family), that basically says "this is a placeholder for something else, not to be printed/read literally."

For example, a (%02d) in a format string for printf is a placeholder for an integer variable that will be printed in decimal (%02d) and padded to at least two digits, with zeros if necessary.

The actual integer is supplied by you in an an argument to the function, e.g. printf("%02d",5); would print 05 on screen, (%01d) also works similarly

Same hold for Java and other languages too :)

How to perform grep operation on all files in a directory?

If you want to do multiple commands, you could use:

for I in `ls *.sql`
do
    grep "foo" $I >> foo.log
    grep "bar" $I >> bar.log
done

Hide div if screen is smaller than a certain width

Use media queries. Your CSS code would be:

@media screen and (max-width: 1024px) {
    .yourClass {
        display: none !important;
    }
}

How can I get a resource "Folder" from inside my jar File?

Another solution, you can do it using ResourceLoader like this:

import org.springframework.core.io.Resource;
import org.apache.commons.io.FileUtils;

@Autowire
private ResourceLoader resourceLoader;

...

Resource resource = resourceLoader.getResource("classpath:/path/to/you/dir");
File file = resource.getFile();
Iterator<File> fi = FileUtils.iterateFiles(file, null, true);
while(fi.hasNext()) {
    load(fi.next())
}

Inconsistent Accessibility: Parameter type is less accessible than method

When I received this error, I had a "helper" class that I did not declare as public that caused this issue inside of the class that used the "helper" class. Making the "helper" class public solved this error, as in:

public ServiceClass { public ServiceClass(HelperClass _helper) { } }

public class HelperClass {} // Note the public HelperClass that solved my issue.

This may help someone else who encounters this.

Bootstrap 3 Glyphicons are not working

This answer is for anyone using Nancy (NancyFx).

I have an ASP.NET-hosted NancyFX app, and I obtained Boostrap via NuGet.

My glyphicons were not working, but it turned out not to be an issue of bad font files, incorrect CSS relative directory paths, or any of the other things mentioned in the other answers.

The problem was that I was missing a convention, telling Nancy where to look for content. Once I realized that, the solution was simply to add the following overload to my bootstrapper file:

protected override void ConfigureConventions(NancyConventions nancyConventions)
{
    base.ConfigureConventions(nancyConventions);
    nancyConventions.StaticContentsConventions.Add(
        StaticContentConventionBuilder.AddDirectory("/fonts"));
    nancyConventions.StaticContentsConventions.Add(
        StaticContentConventionBuilder.AddDirectory("/Scripts"));
}

how to create a logfile in php?

To write to a log file and make a new one each day, you could use date("j.n.Y") as part of the filename.

//Something to write to txt log
$log  = "User: ".$_SERVER['REMOTE_ADDR'].' - '.date("F j, Y, g:i a").PHP_EOL.
        "Attempt: ".($result[0]['success']=='1'?'Success':'Failed').PHP_EOL.
        "User: ".$username.PHP_EOL.
        "-------------------------".PHP_EOL;
//Save string to log, use FILE_APPEND to append.
file_put_contents('./log_'.date("j.n.Y").'.log', $log, FILE_APPEND);

So you would place that within your hasAccess() method.

public function hasAccess($username,$password){
    $form = array();
    $form['username'] = $username;
    $form['password'] = $password;

    $securityDAO = $this->getDAO('SecurityDAO');
    $result = $securityDAO->hasAccess($form);

    //Write action to txt log
    $log  = "User: ".$_SERVER['REMOTE_ADDR'].' - '.date("F j, Y, g:i a").PHP_EOL.
            "Attempt: ".($result[0]['success']=='1'?'Success':'Failed').PHP_EOL.
            "User: ".$username.PHP_EOL.
            "-------------------------".PHP_EOL;
    //-
    file_put_contents('./log_'.date("j.n.Y").'.txt', $log, FILE_APPEND);

    if($result[0]['success']=='1'){
        $this->Session->add('user_id', $result[0]['id']);
        //$this->Session->add('username', $result[0]['username']);
        //$this->Session->add('roleid', $result[0]['roleid']);
        return $this->status(0,true,'auth.success',$result);
    }else{
        return $this->status(0,false,'auth.failed',$result);
    }
}

Is there a "standard" format for command line/shell help text?

We are running Linux, a mostly POSIX-compliant OS. POSIX standards it should be: Utility Argument Syntax.

  • An option is a hyphen followed by a single alphanumeric character, like this: -o.
  • An option may require an argument (which must appear immediately after the option); for example, -o argument or -oargument.
  • Options that do not require arguments can be grouped after a hyphen, so, for example, -lst is equivalent to -t -l -s.
  • Options can appear in any order; thus -lst is equivalent to -tls.
  • Options can appear multiple times.
  • Options precede other nonoption arguments: -lst nonoption.
  • The -- argument terminates options.
  • The - option is typically used to represent one of the standard input streams.

How do you get a timestamp in JavaScript?

Here is another solution to generate a timestamp in JavaScript - including a padding method for single numbers - using day, month, year, hour, minute and seconds in its result (working example at jsfiddle):

var pad = function(int) { return int < 10 ? 0 + int : int; };
var timestamp = new Date();

    timestamp.day = [
        pad(timestamp.getDate()),
        pad(timestamp.getMonth() + 1), // getMonth() returns 0 to 11.
        timestamp.getFullYear()
    ];

    timestamp.time = [
        pad(timestamp.getHours()),
        pad(timestamp.getMinutes()),
        pad(timestamp.getSeconds())
    ];

timestamp.now = parseInt(timestamp.day.join("") + timestamp.time.join(""));
alert(timestamp.now);

MySQL select where column is not empty

If there are spaces in the phone2 field from inadvertant data entry, you can ignore those records with the IFNULL and TRIM functions:

SELECT phone, phone2
FROM jewishyellow.users
WHERE phone LIKE '813%'
    AND TRIM(IFNULL(phone2,'')) <> '';

Datetime in C# add days

Why do you use Int64? AddDays demands a double-value to be added. Then you'll need to use the return-value of AddDays. See here.

Plotting multiple time series on the same plot using ggplot()

ggplot allows you to have multiple layers, and that is what you should take advantage of here.

In the plot created below, you can see that there are two geom_line statements hitting each of your datasets and plotting them together on one plot. You can extend that logic if you wish to add any other dataset, plot, or even features of the chart such as the axis labels.

library(ggplot2)

jobsAFAM1 <- data.frame(
  data_date = runif(5,1,100),
  Percent.Change = runif(5,1,100)
)

jobsAFAM2 <- data.frame(
  data_date = runif(5,1,100),
  Percent.Change = runif(5,1,100)
)

ggplot() + 
  geom_line(data = jobsAFAM1, aes(x = data_date, y = Percent.Change), color = "red") +
  geom_line(data = jobsAFAM2, aes(x = data_date, y = Percent.Change), color = "blue") +
  xlab('data_date') +
  ylab('percent.change')

When do you use the "this" keyword?

You should not use "this" unless you absolutely must.

There IS a penalty associated with unnecessary verbosity. You should strive for code that is exactly as long as it needs to be, and no longer.

What is the current directory in a batch file?

%__CD__% , %CD% , %=C:%

There's also another dynamic variable %__CD__% which points to the current directory but alike %CD% it has a backslash at the end. This can be useful if you want to append files to the current directory.

With %=C:% %=D:% you can access the last accessed directory for the corresponding drive. If the variable is not defined you haven't accessed the drive on the current cmd session.

And %__APPDIR__% expands to the executable that runs the current script a.k.a. cmd.exe directory.

Make a link open a new window (not tab)

That will open a new window, not tab (with JavaScript, but quite laconically):

<a href="print.html"  
    onclick="window.open('print.html', 
                         'newwindow', 
                         'width=300,height=250'); 
              return false;"
 >Print</a>

sqlite copy data from one table to another

INSERT INTO Destination SELECT * FROM Source;

See SQL As Understood By SQLite: INSERT for a formal definition.

VBA macro that search for file in multiple subfolders

I actually just found this today for something I'm working on. This will return file paths for all files in a folder and its subfolders.

Dim colFiles As New Collection
RecursiveDir colFiles, "C:\Users\Marek\Desktop\Makro\", "*.*", True
Dim vFile As Variant

For Each vFile In colFiles
     'file operation here or store file name/path in a string array for use later in the script
     filepath(n) = vFile
     filename = fso.GetFileName(vFile) 'If you want the filename without full path
     n=n+1
Next vFile


'These two functions are required
Public Function RecursiveDir(colFiles As Collection, strFolder As String, strFileSpec As String, bIncludeSubfolders As Boolean)
Dim strTemp As String
Dim colFolders As New Collection
Dim vFolderName As Variant
strFolder = TrailingSlash(strFolder)
strTemp = Dir(strFolder & strFileSpec)
Do While strTemp <> vbNullString
    colFiles.Add strFolder & strTemp
    strTemp = Dir
Loop
If bIncludeSubfolders Then

    strTemp = Dir(strFolder, vbDirectory)
    Do While strTemp <> vbNullString
        If (strTemp <> ".") And (strTemp <> "..") Then
            If (GetAttr(strFolder & strTemp) And vbDirectory) <> 0 Then
                colFolders.Add strTemp
            End If
        End If
        strTemp = Dir
    Loop
    'Call RecursiveDir for each subfolder in colFolders
    For Each vFolderName In colFolders
        Call RecursiveDir(colFiles, strFolder & vFolderName, strFileSpec, True)
    Next vFolderName
End If
End Function

Public Function TrailingSlash(strFolder As String) As String
If Len(strFolder) > 0 Then
    If Right(strFolder, 1) = "\" Then
        TrailingSlash = strFolder
    Else
        TrailingSlash = strFolder & "\"
    End If
End If
End Function

This is adapted from a post by Ammara Digital Image Solutions.(http://www.ammara.com/access_image_faq/recursive_folder_search.html).

UnexpectedRollbackException: Transaction rolled back because it has been marked as rollback-only

The answer of Shyam was right. I already faced with this issue before. It's not a problem, it's a SPRING feature. "Transaction rolled back because it has been marked as rollback-only" is acceptable.

Conclusion

  • USE REQUIRES_NEW if you want to commit what did you do before exception (Local commit)
  • USE REQUIRED if you want to commit only when all processes are done (Global commit) And you just need to ignore "Transaction rolled back because it has been marked as rollback-only" exception. But you need to try-catch out side the caller processNextRegistrationMessage() to have a meaning log.

Let's me explain more detail:

Question: How many Transaction we have? Answer: Only one

Because you config the PROPAGATION is PROPAGATION_REQUIRED so that the @Transaction persist() is using the same transaction with the caller-processNextRegistrationMessage(). Actually, when we get an exception, the Spring will set rollBackOnly for the TransactionManager so the Spring will rollback just only one Transaction.

Question: But we have a try-catch outside (), why does it happen this exception? Answer Because of unique Transaction

  1. When persist() method has an exception
  2. Go to the catch outside

    Spring will set the rollBackOnly to true -> it determine we must 
    rollback the caller (processNextRegistrationMessage) also.
    
  3. The persist() will rollback itself first.

  4. Throw an UnexpectedRollbackException to inform that, we need to rollback the caller also.
  5. The try-catch in run() will catch UnexpectedRollbackException and print the stack trace

Question: Why we change PROPAGATION to REQUIRES_NEW, it works?

Answer: Because now the processNextRegistrationMessage() and persist() are in the different transaction so that they only rollback their transaction.

Thanks

Split string into strings by length?

>>> x = "qwertyui"
>>> chunks, chunk_size = len(x), len(x)/4
>>> [ x[i:i+chunk_size] for i in range(0, chunks, chunk_size) ]
['qw', 'er', 'ty', 'ui']

How to format an inline code in Confluence?

The easiest way I've found to do this is to write in markdown right from the start of the line. Press Ctrl+D (shortcut for opening the markup input dialog) and type markdown. The normal wiki editor doesn't seem to be very good for precise formatting. It doesn't seem to know much about character styles and only knows paragraph styles.

Making a UITableView scroll when text field is selected

The simplest solution for Swift:

override func viewDidLoad() {
    super.viewDidLoad()
    
    searchBar?.becomeFirstResponder()
    NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(MyViewController.keyboardWillShow(_:)), name: UIKeyboardDidShowNotification, object: nil)
    NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(MyViewController.keyboardWillHide(_:)), name: UIKeyboardDidHideNotification, object: nil)
}

deinit {
    NSNotificationCenter.defaultCenter().removeObserver(self)
}

func keyboardWillShow(notification: NSNotification) {
    if let userInfo = notification.userInfo {
        if let keyboardHeight = userInfo[UIKeyboardFrameEndUserInfoKey]?.CGRectValue.size.height {
            tableView.contentInset = UIEdgeInsetsMake(0, 0, keyboardHeight, 0)
        }
    }
}

func keyboardWillHide(notification: NSNotification) {
    UIView.animateWithDuration(0.2, animations: { self.table_create_issue.contentInset = UIEdgeInsetsMake(0, 0, 0, 0) })
    // For some reason adding inset in keyboardWillShow is animated by itself but removing is not, that's why we have to use animateWithDuration here
    }

For Swift 4.2 or greater

override func viewDidLoad() {
    super.viewDidLoad()
    searchBar?.becomeFirstResponder()
    NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillShow), name: UIResponder.keyboardDidShowNotification, object: nil)
    NotificationCenter.default.addObserver(self, selector: #selector(self.keyboardWillHide), name: UIResponder.keyboardDidHideNotification, object: nil)
}

deinit {
    NotificationCenter.default.removeObserver(self)
}

 @objc func keyboardWillShow(notification: NSNotification) {
    if let userInfo = notification.userInfo {
            let keyboardHeight = (userInfo[UIResponder.keyboardFrameEndUserInfoKey] as AnyObject).cgRectValue.size.height
            accountSettingsTableView.contentInset = UIEdgeInsets(top: 0, left: 0, bottom: keyboardHeight, right: 0)
        
    }
}
@objc func keyboardWillHide(notification: NSNotification) {
    UIView.animate(withDuration: 0.2, animations: { self.accountSettingsTableView.contentInset = UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0) })}
}

Recommendation for compressing JPG files with ImageMagick

I use always:

  • quality in 85
  • progressive (comprobed compression)
  • a very tiny gausssian blur to optimize the size (0.05 or 0.5 of radius) depends on the quality and size of the picture, this notably optimizes the size of the jpeg.
  • Strip any comment or EXIF metadata

in imagemagick should be

convert -strip -interlace Plane -gaussian-blur 0.05 -quality 85% source.jpg result.jpg

or in the newer version:

magick source.jpg -strip -interlace Plane -gaussian-blur 0.05 -quality 85% result.jpg

Source.

From @Fordi in the comments (Don't forget to upvote him if you like this): If you dislike blurring, use -sampling-factor 4:2:0 instead. What this does is reduce the chroma channel's resolution to half, without messing with the luminance resolution that your eyes latch onto. If you want better fidelity in the conversion, you can get a slight improvement without an increase in filesize by specifying -define jpeg:dct-method=float - that is, use the more accurate floating point discrete cosine transform, rather than the default fast integer version.

Running Bash commands in Python

It is possible you use the bash program, with the parameter -c for execute the commands:

bashCommand = "cwm --rdf test.rdf --ntriples > test.nt"
output = subprocess.check_output(['bash','-c', bashCommand])

javac option to compile all java files under a given directory recursively

I've been using this in an Xcode JNI project to recursively build my test classes:

find ${PROJECT_DIR} -name "*.java" -print | xargs javac -g -classpath ${BUILT_PRODUCTS_DIR} -d ${BUILT_PRODUCTS_DIR}

What's the strangest corner case you've seen in C# or .NET?

I found a second really strange corner case that beats my first one by a long shot.

String.Equals Method (String, String, StringComparison) is not actually side effect free.

I was working on a block of code that had this on a line by itself at the top of some function:

stringvariable1.Equals(stringvariable2, StringComparison.InvariantCultureIgnoreCase);

Removing that line lead to a stack overflow somewhere else in the program.

The code turned out to be installing a handler for what was in essence a BeforeAssemblyLoad event and trying to do

if (assemblyfilename.EndsWith("someparticular.dll", StringComparison.InvariantCultureIgnoreCase))
{
    assemblyfilename = "someparticular_modified.dll";
}

By now I shouldn't have to tell you. Using a culture that hasn't been used before in a string comparison causes an assembly load. InvariantCulture is not an exception to this.

How do I space out the child elements of a StackPanel?

Use Margin or Padding, applied to the scope within the container:

<StackPanel>
    <StackPanel.Resources>
        <Style TargetType="{x:Type TextBox}">
            <Setter Property="Margin" Value="0,10,0,0"/>
        </Style>
    </StackPanel.Resources> 
    <TextBox Text="Apple"/>
    <TextBox Text="Banana"/>
    <TextBox Text="Cherry"/>
</StackPanel>

EDIT: In case you would want to re-use the margin between two containers, you can convert the margin value to a resource in an outer scope, f.e.

<Window.Resources>
    <Thickness x:Key="tbMargin">0,10,0,0</Thickness>
</Window.Resources>

and then refer to this value in the inner scope

<StackPanel.Resources>
    <Style TargetType="{x:Type TextBox}">
        <Setter Property="Margin" Value="{StaticResource tbMargin}"/>
    </Style>
</StackPanel.Resources>

Can Android Studio be used to run standard Java projects?

Tested on Android Studio 0.8.6 - 3.5

Using this method you can have Java modules and Android modules in the same project and also have the ability to compile and run Java modules as stand alone Java projects.

  1. Open your Android project in Android Studio. If you do not have one, create one.
  2. Click File > New Module. Select Java Library and click Next.
  3. Fill in the package name, etc and click Finish. You should now see a Java module inside your Android project.
  4. Add your code to the Java module you've just created.
  5. Click on the drop down to the left of the run button. Click Edit Configurations...
  6. In the new window, click on the plus sign at the top left of the window and select Application
  7. A new application configuration should appear, enter in the details such as your main class and classpath of your module.
  8. Click OK.

Now if you click run, this should compile and run your Java module.

If you get the error Error: Could not find or load main class..., just enter your main class (as you've done in step 7) again even if the field is already filled in. Click Apply and then click Ok.

My usage case: My Android app relies on some precomputed files to function. These precomputed files are generated by some Java code. Since these two things go hand in hand, it makes the most sense to have both of these modules in the same project.

NEW - How to enable Kotlin in your standalone project

If you want to enable Kotlin inside your standalone project, do the following.

  1. Continuing from the last step above, add the following code to your project level build.gradle (lines to add are denoted by >>>):

    buildscript {
        >>> ext.kotlin_version = '1.2.51'
        repositories {
            google()
            jcenter()
        }
        dependencies {
            classpath 'com.android.tools.build:gradle:3.1.3'
            >>> classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    
            // NOTE: Do not place your application dependencies here; they belong
            // in the individual module build.gradle files
        }
    }
    ...
    
  2. Add the following code to your module level build.gradle (lines to add are denoted by >>>):

    apply plugin: 'java-library'
    >>> apply plugin: 'kotlin'
    
    dependencies {
        implementation fileTree(dir: 'libs', include: ['*.jar'])
        >>> implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
        >>> runtimeClasspath files(compileKotlin.destinationDir)
    }
    ...
    
  3. Bonus step: Convert your main function to Kotlin! Simply change your main class to:

    object Main {
        ...
        @JvmStatic
        fun main(args: Array<String>) {
            // do something
        }
        ...
    }
    

Starting a node.js server

Run cmd and then run node server.js. In your example, you are trying to use the REPL to run your command, which is not going to work. The ellipsis is node.js expecting more tokens before closing the current scope (you can type code in and run it on the fly here)

How do I lock the orientation to portrait mode in a iPhone Web Application?

I came up with this CSS only method of rotating the screen using media queries. The queries are based on screen sizes that I found here. 480px seemed to be a good as no/few devices had more than 480px width or less than 480px height.

@media (max-height: 480px) and (min-width: 480px) and (max-width: 600px) { 
    html{
        -webkit-transform: rotate(-90deg);
           -moz-transform: rotate(-90deg);
            -ms-transform: rotate(-90deg);
             -o-transform: rotate(-90deg);
                transform: rotate(-90deg);
        -webkit-transform-origin: left top;
           -moz-transform-origin: left top;
            -ms-transform-origin: left top;
             -o-transform-origin: left top;
                transform-origin: left top;
        width: 320px; /*this is the iPhone screen width.*/
        position: absolute;
        top: 100%;
            left: 0
    }
}

How do I get git to default to ssh and not https for new repositories

Set up a repository's origin branch to be SSH

The GitHub repository setup page is just a suggested list of commands (and GitHub now suggests using the HTTPS protocol). Unless you have administrative access to GitHub's site, I don't know of any way to change their suggested commands.

If you'd rather use the SSH protocol, simply add a remote branch like so (i.e. use this command in place of GitHub's suggested command). To modify an existing branch, see the next section.

$ git remote add origin [email protected]:nikhilbhardwaj/abc.git

Modify a pre-existing repository

As you already know, to switch a pre-existing repository to use SSH instead of HTTPS, you can change the remote url within your .git/config file.

[remote "origin"]
    fetch = +refs/heads/*:refs/remotes/origin/*
    -url = https://github.com/nikhilbhardwaj/abc.git
    +url = [email protected]:nikhilbhardwaj/abc.git

A shortcut is to use the set-url command:

$ git remote set-url origin [email protected]:nikhilbhardwaj/abc.git

More information about the SSH-HTTPS switch

Run jar file with command line arguments

For the question

How can i run a jar file in command prompt but with arguments

.

To pass arguments to the jar file at the time of execution

java -jar myjar.jar arg1 arg2

In the main() method of "Main-Class" [mentioned in the manifest.mft file]of your JAR file. you can retrieve them like this:

String arg1 = args[0];
String arg2 = args[1];

Draggable div without jQuery UI

What I saw above is complicate.....

Here is some code can refer to.

$("#box").on({
                mousedown:function(e)
                {
                  dragging = true;
                  dragX = e.clientX - $(this).position().left;
                  //To calculate the distance between the cursor pointer and box 
                  dragY = e.clientY - $(this).position().top;
                },
                mouseup:function(){dragging = false;},
                  //If not set this on/off,the move will continue forever
                mousemove:function(e)
                {
                  if(dragging)
                  $(this).offset({top:e.clientY-dragY,left:e.clientX-dragX});

                }
            })

dragging,dragX,dragY may place as the global variable.

It's a simple show about this issue,but there is some bug about this method.

If it's your need now,here's the Example here.

How to instantiate, initialize and populate an array in TypeScript?

An other solution:

interface bar {
    length: number;
}

bars = [{
  length: 1
} as bar];

sql server Get the FULL month name from a date

Most answers are a bit more complicated than necessary, or don't provide the exact format requested.

select Format(getdate(), 'MMMM dd yyyy') --returns 'October 01 2020', note the leading zero
select Format(getdate(), 'MMMM d yyyy') --returns the desired format with out the leading zero: 'October 1 2020'

If you want a comma, as you normally would, use:

select Format(getdate(), 'MMMM d, yyyy') --returns 'October 1, 2020'

Note: even though there is only one 'd' for the day, it will become a 2 digit day when needed.

Mongoose: Find, modify, save

The user parameter of your callback is an array with find. Use findOne instead of find when querying for a single instance.

User.findOne({username: oldUsername}, function (err, user) {
    user.username = newUser.username;
    user.password = newUser.password;
    user.rights = newUser.rights;

    user.save(function (err) {
        if(err) {
            console.error('ERROR!');
        }
    });
});

Bi-directional Map in Java?

Apache commons collections has a BidiMap

How to clear https proxy setting of NPM?

I was struggling with this for ages. What I finally did was go into the .npmrc file (which can be found in the user's directory followed by the user's name, ie. C:\Users\erikj/.npmrc), opened it with a text editor, manually removed any proxy settings and changed the http:// setting to https://. In this case, it is a matter of experimenting whether http or https will work for you. In my case, https worked. Go figure.

Excel VBA - Delete empty rows

How about

sub foo()
  dim r As Range, rows As Long, i As Long
  Set r = ActiveSheet.Range("A1:Z50")
  rows = r.rows.Count
  For i = rows To 1 Step (-1)
    If WorksheetFunction.CountA(r.rows(i)) = 0 Then r.rows(i).Delete
  Next
End Sub

Try this

Option Explicit

Sub Sample()
    Dim i As Long
    Dim DelRange As Range

    On Error GoTo Whoa

    Application.ScreenUpdating = False

    For i = 1 To 50
        If Application.WorksheetFunction.CountA(Range("A" & i & ":" & "Z" & i)) = 0 Then
            If DelRange Is Nothing Then
                Set DelRange = Range("A" & i & ":" & "Z" & i)
            Else
                Set DelRange = Union(DelRange, Range("A" & i & ":" & "Z" & i))
            End If
        End If
    Next i

    If Not DelRange Is Nothing Then DelRange.Delete shift:=xlUp
LetsContinue:
    Application.ScreenUpdating = True

    Exit Sub
Whoa:
    MsgBox Err.Description
    Resume LetsContinue
End Sub

IF you want to delete the entire row then use this code

Option Explicit

Sub Sample()
    Dim i As Long
    Dim DelRange As Range

    On Error GoTo Whoa

    Application.ScreenUpdating = False

    For i = 1 To 50
        If Application.WorksheetFunction.CountA(Range("A" & i & ":" & "Z" & i)) = 0 Then
            If DelRange Is Nothing Then
                Set DelRange = Rows(i)
            Else
                Set DelRange = Union(DelRange, Rows(i))
            End If
        End If
    Next i

    If Not DelRange Is Nothing Then DelRange.Delete shift:=xlUp
LetsContinue:
    Application.ScreenUpdating = True

    Exit Sub
Whoa:
    MsgBox Err.Description
    Resume LetsContinue
End Sub

Is it possible to get a history of queries made in postgres

You can use like

\s 

it will fetch you all command history of the terminal, to export it to file using

\s filename

how to use ng-option to set default value of select element

This answer is more usefull when you are bringing data from a DB, make modifications and then persist the changes.

 <select  ng-options="opt.id as opt.name for opt in users" ng-model="selectedUser"></select>

Check the example here:

http://plnkr.co/edit/HrT5vUMJOtP9esGngbIV

Creating a range of dates in Python

Based on answers I wrote for myself this:

import datetime;
print [(datetime.date.today() - datetime.timedelta(days=x)).strftime('%Y-%m-%d') for x in range(-5, 0)]

Output:

['2017-12-11', '2017-12-10', '2017-12-09', '2017-12-08', '2017-12-07']

The difference is that I get the 'date' object, not the 'datetime.datetime' one.

Eclipse error, "The selection cannot be launched, and there are no recent launches"

Follow these steps to run your application on the device connected. 1. Change directories to the root of your Android project and execute: ant debug 2. Make sure the Android SDK platform-tools/ directory is included in your PATH environment variable, then execute: adb install bin/<*your app name*>-debug.apk On your device, locate <*your app name*> and open it.

Refer Running App

how can I copy a conditional formatting in Excel 2010 to other cells, which is based on a other cells content?

You can do this in the 'Conditional Formatting' tool in the Home tab of Excel 2010.

Assuming the existing rule is 'Use a formula to dtermine which cells to format':

Edit the existing rule, so that the 'Formula' refers to relative rows and columns (i.e. remove $s), and then in the 'Applies to' box, click the icon to make the sheet current and select the cells you want the formatting to apply to (absolute cell references are ok here), then go back to the tool panel and click Apply.

This will work assuming the relative offsets are appropriate throughout your desired apply-to range.

You can copy conditional formatting from one cell to another or a range using copy and paste-special with formatting only, assuming you do not mind copying the normal formats.

Is try-catch like error handling possible in ASP Classic?

A rather nice way to handle this for missing COM classes:

Dim o:Set o = Nothing
On Error Resume Next
Set o = CreateObject("foo.bar")
On Error Goto 0
If o Is Nothing Then
  Response.Write "Oups, foo.bar isn't installed on this server!"
Else
  Response.Write "Foo bar found, yay."
End If

Copy folder structure (without files) from one location to another

Substitute target_dir and source_dir with the appropriate values:

cd target_dir && (cd source_dir; find . -type d ! -name .) | xargs -i mkdir -p "{}"

Tested on OSX+Ubuntu.

Change the Bootstrap Modal effect

Here is pure Bootstrap 4 with CSS 3 solution.

<div class="modal fade2" id="exampleModal" tabindex="-1" role="dialog" aria-labelledby="exampleModalLabel" aria-hidden="true">
  <div class="modal-dialog" role="document">
    <div class="modal-content">
      <div class="modal-header">
      </div>
      <div class="modal-body">
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-primary" data-dismiss="modal">OK</button>
      </div>
    </div>
  </div>
</div>
.fade2 {
    transform: scale(0.9);
    opacity: 0;
    transition: all .2s linear;
    display: block !important;
}

.fade2.show {
    opacity: 1;
    transform: scale(1);
}
$('#exampleModal').modal();

function afterModalTransition(e) {
  e.setAttribute("style", "display: none !important;");
}
$('#exampleModal').on('hide.bs.modal', function (e) {
    setTimeout( () => afterModalTransition(this), 200);
})

Full example here.

Maybe it will help someone.

--

Thank you @DavidDomain too.

How to get relative path of a file in visual studio?

Omit the "~\":

var path = @"FolderIcon\Folder.ico";

~\ doesn't mean anything in terms of the file system. The only place I've seen that correctly used is in a web app, where ASP.NET replaces the tilde with the absolute path to the root of the application.

You can typically assume the paths are relative to the folder where the EXE is located. Also, make sure that the image is specified as "content" and "copy if newer"/"copy always" in the properties tab in Visual Studio.

SQL Server Group by Count of DateTime Per Hour?

Alternatively, just GROUP BY the hour and day:

SELECT  CAST(Startdate as DATE) as 'StartDate', 
        CAST(DATEPART(Hour, StartDate) as varchar) + ':00' as 'Hour', 
        COUNT(*) as 'Ct'
FROM #Events
GROUP BY CAST(Startdate as DATE), DATEPART(Hour, StartDate)
ORDER BY CAST(Startdate as DATE) ASC

output:

StartDate   Hour    Ct
2007-01-01  0:00    3
2007-01-02  5:00    2
2007-01-03  4:00    1
2007-01-07  3:00    1

Format XML string to print friendly XML string

You will have to parse the content somehow ... I find using LINQ the most easy way to do it. Again, it all depends on your exact scenario. Here's a working example using LINQ to format an input XML string.

string FormatXml(string xml)
{
     try
     {
         XDocument doc = XDocument.Parse(xml);
         return doc.ToString();
     }
     catch (Exception)
     {
         // Handle and throw if fatal exception here; don't just ignore them
         return xml;
     }
 }

[using statements are ommitted for brevity]

How do I convert ticks to minutes?

DateTime mydate = new Date(2012,3,2,5,2,0);
int minute = mydate/600000000;

will return minutes of from given date (mydate) to current time.hope this help.cheers

How to insert table values from one database to another database?

    --Code for same server
USE [mydb1]
GO

INSERT INTO dbo.mytable1 (
    column1
    ,column2
    ,column3
    ,column4
    )
SELECT column1
    ,column2
    ,column3
    ,column4
FROM [mydb2].dbo.mytable2 --WHERE any condition

/*
steps-
    1-  [mydb1] means our opend connection database 
    2-  mytable1 the table in mydb1 database where we want insert record
    3-  mydb2 another database.
    4-  mytable2 is database table where u fetch record from it. 
*/

--Code for different server
        USE [mydb1]

    SELECT *
    INTO mytable1
    FROM OPENDATASOURCE (
            'SQLNCLI'
            ,'Data Source=XXX.XX.XX.XXX;Initial Catalog=mydb2;User ID=XXX;Password=XXXX'
            ).[mydb2].dbo.mytable2

        /*  steps - 
            1-  [mydb1] means our opend connection database 
            2-  mytable1 means create copy table in mydb1 database where we want 
                insert record
            3-  XXX.XX.XX.XXX - another server name.
            4-  mydb2 another server database.
            5-  write User id and Password of another server credential
            6-  mytable2 is another server table where u fetch record from it. */

How to read from stdin with fgets()?

here a concatenation solution:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define BUFFERSIZE 10

int main() {
  char *text = calloc(1,1), buffer[BUFFERSIZE];
  printf("Enter a message: \n");
  while( fgets(buffer, BUFFERSIZE , stdin) ) /* break with ^D or ^Z */
  {
    text = realloc( text, strlen(text)+1+strlen(buffer) );
    if( !text ) ... /* error handling */
    strcat( text, buffer ); /* note a '\n' is appended here everytime */
    printf("%s\n", buffer);
  }
  printf("\ntext:\n%s",text);
  return 0;
}

Java path..Error of jvm.cfg

In our system, for "java(jre)" for runtime purpose is availed, So If you install any different version of java, propbably the version before the one which is already installed.

E.g.; my windows 8.1 I have runtime java version of 8, then when I install Ver7 it is bu default taking V8, yet I uninstall 8, In this kind of Scenarios, Removing java.exe from c:\windows\system32 makes my java runtime work

SVN 405 Method Not Allowed

I also met this problem just now and solved it in this way. So I recorded it here, and I wish it be useful for others.

Scenario:

  1. Before I commit the code, revision: 100
  2. (Someone else commits the code... revision increased to 199)
  3. I (forgot to run "svn up", ) commit the code, now my revision: 200
  4. I run "svn up".

The error occurred.

Solution:

  1. $ mv current_copy copy_back # Rename the current code copy
  2. $ svn checkout current_copy # Check it out again
  3. $ cp copy_back/ current_copy # Restore your modifications

How to change an application icon programmatically in Android?

You cannot change the manifest or the resource in the signed-and-sealed APK, except through a software upgrade.

Convert alphabet letters to number in Python

If you are looking the opposite like 1 = A , 2 = B etc, you can use the following code. Please note that I have gone only up to 2 levels as I had to convert divisions in a class to A, B, C etc.

loopvariable = 0 
    numberofdivisions = 53
    while (loopvariable <numberofdivisions):
        if(loopvariable<26):
            print(chr(65+loopvariable))
        loopvariable +=1
        if(loopvariable > 26 and loopvariable <53):
            print(chr(65)+chr(65+(loopvariable-27)))

Changing element style attribute dynamically using JavaScript

Assuming you have HTML like this:

<div id='thediv'></div>

If you want to modify the style attribute of this div, you'd use

document.getElementById('thediv').style.[ATTRIBUTE] = '[VALUE]'

Replace [ATTRIBUTE] with the style attribute you want. Remember to remove '-' and make the following letter uppercase.

Examples

document.getElementById('thediv').style.display = 'none'; //changes the display
document.getElementById('thediv').style.paddingLeft = 'none'; //removes padding

Can clearInterval() be called inside setInterval()?

Yes you can. You can even test it:

_x000D_
_x000D_
var i = 0;_x000D_
var timer = setInterval(function() {_x000D_
  console.log(++i);_x000D_
  if (i === 5) clearInterval(timer);_x000D_
  console.log('post-interval'); //this will still run after clearing_x000D_
}, 200);
_x000D_
_x000D_
_x000D_

In this example, this timer clears when i reaches 5.

How to print object array in JavaScript?

If you are using Chrome, you could also use

console.log( yourArray );

Doing a join across two databases with different collations on SQL Server and getting an error

You can use the collate clause in a query (I can't find my example right now, so my syntax is probably wrong - I hope it points you in the right direction)

select sone_field collate SQL_Latin1_General_CP850_CI_AI
  from table_1
    inner join table_2
      on (table_1.field collate SQL_Latin1_General_CP850_CI_AI = table_2.field)
  where whatever

Adding new line of data to TextBox

Following are the ways

  1. From the code (the way you have mentioned) ->

    displayBox.Text += sent + "\r\n";
    

    or

    displayBox.Text += sent + Environment.NewLine;
    
  2. From the UI
    a) WPF

    Set TextWrapping="Wrap" and AcceptsReturn="True"   
    

    Press Enter key to the textbox and new line will be created

    b) Winform text box

    Set TextBox.MultiLine and TextBox.AcceptsReturn to true
    

Can't bind to 'ngModel' since it isn't a known property of 'input'

Simple solution: In file app.module.ts -

Example 1

import {FormsModule} from "@angular/forms";
// Add in imports

imports: [
 BrowserModule,
 FormsModule
 ],

Example 2

If you want to use [(ngModel)] then you have to import FormsModule in app.module.ts:

import { FormsModule  } from "@angular/forms";
@NgModule({
  declarations: [
    AppComponent, videoComponent, tagDirective,
  ],
  imports: [
    BrowserModule,  FormsModule

  ],
  providers: [ApiServices],
  bootstrap: [AppComponent]
})
export class AppModule { }

Mockito: Trying to spy on method is calling the original method

I've found yet another reason for spy to call the original method.

Someone had the idea to mock a final class, and found about MockMaker:

As this works differently to our current mechanism and this one has different limitations and as we want to gather experience and user feedback, this feature had to be explicitly activated to be available ; it can be done via the mockito extension mechanism by creating the file src/test/resources/mockito-extensions/org.mockito.plugins.MockMaker containing a single line: mock-maker-inline

Source: https://github.com/mockito/mockito/wiki/What%27s-new-in-Mockito-2#mock-the-unmockable-opt-in-mocking-of-final-classesmethods

After I merged and brought that file to my machine, my tests failed.

I just had to remove the line (or the file), and spy() worked.

Can RDP clients launch remote applications and not desktops

Another way is shown in this CodeProject article:

http://www.codeproject.com/KB/IP/tswindowclipper.aspx

The basic idea is to create a virutal channel that sends the windows position of the app(s) you want to show, then only render that part of the window on the client.

Is there any advantage of using map over unordered_map in case of trivial keys?

From: http://www.cplusplus.com/reference/map/map/

"Internally, the elements in a map are always sorted by its key following a specific strict weak ordering criterion indicated by its internal comparison object (of type Compare).

map containers are generally slower than unordered_map containers to access individual elements by their key, but they allow the direct iteration on subsets based on their order."

jquery Ajax call - data parameters are not being passed to MVC Controller action

If you have trouble with caching ajax you can turn it off:

$.ajaxSetup({cache: false});

Passing arguments forward to another javascript function

Spread operator

The spread operator allows an expression to be expanded in places where multiple arguments (for function calls) or multiple elements (for array literals) are expected.

ECMAScript ES6 added a new operator that lets you do this in a more practical way: ...Spread Operator.

Example without using the apply method:

_x000D_
_x000D_
function a(...args){_x000D_
  b(...args);_x000D_
  b(6, ...args, 8) // You can even add more elements_x000D_
}_x000D_
function b(){_x000D_
  console.log(arguments)_x000D_
}_x000D_
_x000D_
a(1, 2, 3)
_x000D_
_x000D_
_x000D_

Note This snippet returns a syntax error if your browser still uses ES5.

Editor's note: Since the snippet uses console.log(), you must open your browser's JS console to see the result - there will be no in-page result.

It will display this result:

Image of Spread operator arguments example

In short, the spread operator can be used for different purposes if you're using arrays, so it can also be used for function arguments, you can see a similar example explained in the official docs: Rest parameters

Git push error: "origin does not appear to be a git repository"

May be you forgot to run "git --bare init" on the remote? That was my problem

Java - Best way to print 2D array?

That's the best I guess:

   for (int[] row : matrix){
    System.out.println(Arrays.toString(row));
   }

get keys of json-object in JavaScript

[What you have is just an object, not a "json-object". JSON is a textual notation. What you've quoted is JavaScript code using an array initializer and an object initializer (aka, "object literal syntax").]

If you can rely on having ECMAScript5 features available, you can use the Object.keys function to get an array of the keys (property names) in an object. All modern browsers have Object.keys (including IE9+).

Object.keys(jsonData).forEach(function(key) {
    var value = jsonData[key];
    // ...
});

The rest of this answer was written in 2011. In today's world, A) You don't need to polyfill this unless you need to support IE8 or earlier (!), and B) If you did, you wouldn't do it with a one-off you wrote yourself or grabbed from an SO answer (and probably shouldn't have in 2011, either). You'd use a curated polyfill, possibly from es5-shim or via a transpiler like Babel that can be configured to include polyfills (which may come from es5-shim).

Here's the rest of the answer from 2011:

Note that older browsers won't have it. If not, this is one of the ones you can supply yourself:

if (typeof Object.keys !== "function") {
    (function() {
        var hasOwn = Object.prototype.hasOwnProperty;
        Object.keys = Object_keys;
        function Object_keys(obj) {
            var keys = [], name;
            for (name in obj) {
                if (hasOwn.call(obj, name)) {
                    keys.push(name);
                }
            }
            return keys;
        }
    })();
}

That uses a for..in loop (more info here) to loop through all of the property names the object has, and uses Object.prototype.hasOwnProperty to check that the property is owned directly by the object rather than being inherited.

(I could have done it without the self-executing function, but I prefer my functions to have names, and to be compatible with IE you can't use named function expressions [well, not without great care]. So the self-executing function is there to avoid having the function declaration create a global symbol.)

AngularJs event to call after content is loaded

I was using {{myFunction()}} in the template but then found another way here using $timeout inside the controller. Thought I'd share it, works great for me.

angular.module('myApp').controller('myCtrl', ['$timeout',
function($timeout) {
var self = this;

self.controllerFunction = function () { alert('controller function');}

$timeout(function () {
    var vanillaFunction = function () { alert('vanilla function'); }();
    self.controllerFunction();
});

}]);

Disable same origin policy in Chrome

Following on Ola Karlsson answer, indeed the best way would be to open the unsafe Chrome in a different session. This way you don't need to worry about closing all of the currently opened tabs, and also can continue to surf the web securely with the original Chrome session.

These batch files should just work for you on Windows.

Put it in a Chrome_CORS.bat file for easy use

start "" "c:\Program Files (x86)\Google\Chrome\Application\chrome.exe" --user-data-dir="c:/_chrome_dev" --disable-web-security

This one is for Chrome Canary. Canary_CORS.bat

start "" "c:\Users\%USERNAME%\AppData\Local\Google\Chrome SxS\Application\chrome.exe" --user-data-dir="c:/_canary_dev" --disable-web-security

Oracle: how to set user password unexpire?

The following statement causes a user's password to expire:

ALTER USER user PASSWORD EXPIRE;

If you cause a database user's password to expire with PASSWORD EXPIRE, then the user (or the DBA) must change the password before attempting to log in to the database following the expiration. Tools such as SQL*Plus allow the user to change the password on the first attempted login following the expiration.

ALTER USER scott IDENTIFIED BY password;

Will set/reset the users password.

See the alter user doc for more info

Can you use if/else conditions in CSS?

Yet another option (based on whether you want that if statement to be dynamically evaluated or not) is to use the C preprocessor, as described here.

C# importing class into another class doesn't work

using is for namespaces only - if both classes are in the same namespace just drop the using.

You have to reference the assembly created in the first step when you compile the .exe:

csc /t:library /out:MyClass.dll MyClass.cs
csc /reference:MyClass.dll /t:exe /out:MyProgram.exe MyMainClass.cs

You can make things simpler if you just compile the files together:

csc /t:exe /out:MyProgram.exe MyMainClass.cs MyClass.cs

or

csc /t:exe /out:MyProgram.exe *.cs

EDIT: Here's how the files should look like:

MyClass.cs:

namespace MyNamespace {
    public class MyClass {
        void stuff() {

        }
    }
}

MyMainClass.cs:

using System;

namespace MyNamespace {
    public class MyMainClass {
        static void Main() {
            MyClass test = new MyClass();
        }
    }
}

Link a photo with the cell in excel

Hold down the Alt key and drag the pictures to snap to the upper left corner of the cell.

Format the picture and in the Properties tab select "Move but don't size with cells"

Now you can sort the data table by any column and the pictures will stay with the respective data.

This post at SuperUser has a bit more background and screenshots: https://superuser.com/questions/712622/put-an-equation-object-in-an-excel-cell/712627#712627