Programs & Examples On #Stringcomparer

Case insensitive access for generic dictionary

Its not very elegant but in case you cant change the creation of dictionary, and all you need is a dirty hack, how about this:

var item = MyDictionary.Where(x => x.Key.ToLower() == MyIndex.ToLower()).FirstOrDefault();
    if (item != null)
    {
        TheValue = item.Value;
    }

Sorting string array in C#

Actually I don't see any nulls:

given:

static void Main()
        {
            string[] testArray = new string[]
            {
                "aa",
                "ab",
                "ac",
                "ad",
                "ab",
                "af"
            };

            Array.Sort(testArray, StringComparer.InvariantCulture);

            Array.ForEach(testArray, x => Console.WriteLine(x));
        }

I obtained:

enter image description here

Convert list to dictionary using linq and not worrying about duplicates

        DataTable DT = new DataTable();
        DT.Columns.Add("first", typeof(string));
        DT.Columns.Add("second", typeof(string));

        DT.Rows.Add("ss", "test1");
        DT.Rows.Add("sss", "test2");
        DT.Rows.Add("sys", "test3");
        DT.Rows.Add("ss", "test4");
        DT.Rows.Add("ss", "test5");
        DT.Rows.Add("sts", "test6");

        var dr = DT.AsEnumerable().GroupBy(S => S.Field<string>("first")).Select(S => S.First()).
            Select(S => new KeyValuePair<string, string>(S.Field<string>("first"), S.Field<string>("second"))).
           ToDictionary(S => S.Key, T => T.Value);

        foreach (var item in dr)
        {
            Console.WriteLine(item.Key + "-" + item.Value);
        }

LINQ query to return a Dictionary<string, string>

Use the ToDictionary method directly.

var result = 
  // as Jon Skeet pointed out, OrderBy is useless here, I just leave it 
  // show how to use OrderBy in a LINQ query
  myClassCollection.OrderBy(mc => mc.SomePropToSortOn)
                   .ToDictionary(mc => mc.KeyProp.ToString(), 
                                 mc => mc.ValueProp.ToString(), 
                                 StringComparer.OrdinalIgnoreCase);

How can I make git show a list of the files that are being tracked?

The accepted answer only shows files in the current directory's tree. To show all of the tracked files that have been committed (on the current branch), use

git ls-tree --full-tree --name-only -r HEAD
  • --full-tree makes the command run as if you were in the repo's root directory.
  • -r recurses into subdirectories. Combined with --full-tree, this gives you all committed, tracked files.
  • --name-only removes SHA / permission info for when you just want the file paths.
  • HEAD specifies which branch you want the list of tracked, committed files for. You could change this to master or any other branch name, but HEAD is the commit you have checked out right now.

This is the method from the accepted answer to the ~duplicate question https://stackoverflow.com/a/8533413/4880003.

Understanding inplace=True

inplace=True is used depending if you want to make changes to the original df or not.

df.drop_duplicates()

will only make a view of dropped values but not make any changes to df

df.drop_duplicates(inplace  = True)

will drop values and make changes to df.

Hope this helps.:)

ASP.NET: Session.SessionID changes between requests

In my case I figured out that the session cookie had a domain that included www. prefix, while I was requesting page with no www..
Adding www. to the URL immediately fixed the problem. Later I changed cookie's domain to be set to .mysite.com instead of www.mysite.com.

How to append strings using sprintf?

You need:

sprintf(Buffer,"Hello World");
sprintf(Buffer + strlen(Buffer),"Good Morning");
sprintf(Buffer + strlen(Buffer),"Good Afternoon");

and of course you need your buffer to be big enough.

How to view an HTML file in the browser with Visual Studio Code

If you're just on Mac this tasks.json file:

{
    "version": "0.1.0",
    "command": "open",
    "args": ["${file}"],
}

...is all you need to open the current file in Safari, assuming its extension is ".html".

Create tasks.json as described above and invoke it with ?+shift+b.

If you want it to open in Chrome then:

{
    "version": "0.1.0",
    "command": "open",
    "args": ["-a", "Chrome.app", "${file}"],
}

This will do what you want, as in opening in a new tab if the app is already open.

Form inside a form, is that alright?

No we can't nest forms within another form like this

<form name='form1'>
      <form name='form2'>
            //some code here
      </form>
</form>

it will work in some cases but it is not recommended for universal platforms. You can use plenty of SUBMIT buttons inside a single form, but you can't manage a nested form appropriately.

Display back button on action bar

In your onCreate() method add this line

getSupportActionBar().setDisplayHomeAsUpEnabled(true);

and, in the same Activity, add this method to handle the button click

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    if (item.getItemId() == android.R.id.home) {
        this.finish();
        return true;
    }
    return super.onOptionsItemSelected(item);
}

How to remove a row from JTable?

A JTable normally forms the View part of an MVC implementation. You'll want to remove rows from your model. The JTable, which should be listening for these changes, will update to reflect this removal. Hence you won't find removeRow() or similar as a method on JTable.

Entity Framework is Too Slow. What are my options?

I ran into this issue as well. I hate to dump on EF because it works so well, but it is just slow. In most cases I just want to find a record or update/insert. Even simple operations like this are slow. I pulled back 1100 records from a table into a List and that operation took 6 seconds with EF. For me this is too long, even saving takes too long.

I ended up making my own ORM. I pulled the same 1100 records from a database and my ORM took 2 seconds, much faster than EF. Everything with my ORM is almost instant. The only limitation right now is that it only works with MS SQL Server, but it could be changed to work with others like Oracle. I use MS SQL Server for everything right now.

If you would like to try my ORM here is the link and website:

https://github.com/jdemeuse1204/OR-M-Data-Entities

Or if you want to use nugget:

PM> Install-Package OR-M_DataEntities

Documentation is on there as well

Git: "Not currently on any branch." Is there an easy way to get back on a branch, while keeping the changes?

Alternatively, you could setup your submodules so that rather than being in their default detached head state you check out a branch.

Edited to add:

One way is to checkout a particular branch of the submodule when you add it with the -b flag:

git submodule add -b master <remote-repo> <path-to-add-it-to>

Another way is to just go into the submodule directory and just check it out

git checkout master

How do I get the SQLSRV extension to work with PHP, since MSSQL is deprecated?

Quoting http://php.net/manual/en/intro.mssql.php:

The MSSQL extension is not available anymore on Windows with PHP 5.3 or later. SQLSRV, an alternative driver for MS SQL is available from Microsoft: » http://msdn.microsoft.com/en-us/sqlserver/ff657782.aspx.

Once you downloaded that, follow the instructions at this page:

In a nutshell:

Put the driver file in your PHP extension directory.
Modify the php.ini file to include the driver. For example:

extension=php_sqlsrv_53_nts_vc9.dll  

Restart the Web server.

See Also (copied from that page)

The PHP Manual for the SQLSRV extension is located at http://php.net/manual/en/sqlsrv.installation.php and offers the following for Installation:

The SQLSRV extension is enabled by adding appropriate DLL file to your PHP extension directory and the corresponding entry to the php.ini file. The SQLSRV download comes with several driver files. Which driver file you use will depend on 3 factors: the PHP version you are using, whether you are using thread-safe or non-thread-safe PHP, and whether your PHP installation was compiled with the VC6 or VC9 compiler. For example, if you are running PHP 5.3, you are using non-thread-safe PHP, and your PHP installation was compiled with the VC9 compiler, you should use the php_sqlsrv_53_nts_vc9.dll file. (You should use a non-thread-safe version compiled with the VC9 compiler if you are using IIS as your web server). If you are running PHP 5.2, you are using thread-safe PHP, and your PHP installation was compiled with the VC6 compiler, you should use the php_sqlsrv_52_ts_vc6.dll file.

The drivers can also be used with PDO.

Docker: Multiple Dockerfiles in project

In newer versions(>=1.8.0) of docker, you can do this

docker build -f Dockerfile.db .
docker build -f Dockerfile.web .

A big save.

EDIT: update versions per raksja's comment

EDIT: comment from @vsevolod: it's possible to get syntax highlighting in VS code by giving files .Dockerfile extension(instead of name) e.g. Prod.Dockerfile, Test.Dockerfile etc.

how to parse JSONArray in android

Here is a better way for doing it. Hope this helps

protected void onPostExecute(String result) {
                Log.v(TAG + " result);


                if (!result.equals("")) {

                    // Set up variables for API Call
                    ArrayList<String> list = new ArrayList<String>();

                    try {
                        JSONArray jsonArray = new JSONArray(result);

                        for (int i = 0; i < jsonArray.length(); i++) {

                            list.add(jsonArray.get(i).toString());

                        }//end for
                    } catch (JSONException e) {
                        Log.e(TAG, "onPostExecute > Try > JSONException => " + e);
                        e.printStackTrace();
                    }


                    adapter = new ArrayAdapter<String>(ListViewData.this, android.R.layout.simple_list_item_1, android.R.id.text1, list);
                    listView.setAdapter(adapter);
                    listView.setOnItemClickListener(new OnItemClickListener() {
                        @Override
                        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

                            // ListView Clicked item index
                            int itemPosition = position;

                            // ListView Clicked item value
                            String itemValue = (String) listView.getItemAtPosition(position);

                            // Show Alert
                            Toast.makeText( ListViewData.this, "Position :" + itemPosition + "  ListItem : " + itemValue, Toast.LENGTH_LONG).show();
                        }
                    });

                    adapter.notifyDataSetChanged();
...

Docker-Compose with multiple services

The thing is that you are using the option -t when running your container.

Could you check if enabling the tty option (see reference) in your docker-compose.yml file the container keeps running?

version: '2'
services:
  ubuntu:
        build: .
        container_name: ubuntu
        volumes:
            - ~/sph/laravel52:/www/laravel
        ports:
          - "80:80"
        tty: true

Remove or uninstall library previously added : cocoapods

The unwanted side effects of simple folder delete or installing over existing installation have been removed by a script written by Kyle Fuller - deintegrate and here is the proper workflow:

  1. Install clean:

    $ sudo gem install cocoapods-clean
    
  2. Run deintegrate in the folder of the project:

    $ pod deintegrate
    
  3. Clean (this tool is no longer available):

    $ pod clean
    
  4. Modify your podfile (delete the lines with the pods you don't want to use anymore) and run:

    $ pod install
    

Done.

What does the regex \S mean in JavaScript?

The \s metacharacter matches whitespace characters.

String formatting in Python 3

Here are the docs about the "new" format syntax. An example would be:

"({:d} goals, ${:d})".format(self.goals, self.penalties)

If both goals and penalties are integers (i.e. their default format is ok), it could be shortened to:

"({} goals, ${})".format(self.goals, self.penalties)

And since the parameters are fields of self, there's also a way of doing it using a single argument twice (as @Burhan Khalid noted in the comments):

"({0.goals} goals, ${0.penalties})".format(self)

Explaining:

  • {} means just the next positional argument, with default format;
  • {0} means the argument with index 0, with default format;
  • {:d} is the next positional argument, with decimal integer format;
  • {0:d} is the argument with index 0, with decimal integer format.

There are many others things you can do when selecting an argument (using named arguments instead of positional ones, accessing fields, etc) and many format options as well (padding the number, using thousands separators, showing sign or not, etc). Some other examples:

"({goals} goals, ${penalties})".format(goals=2, penalties=4)
"({goals} goals, ${penalties})".format(**self.__dict__)

"first goal: {0.goal_list[0]}".format(self)
"second goal: {.goal_list[1]}".format(self)

"conversion rate: {:.2f}".format(self.goals / self.shots) # '0.20'
"conversion rate: {:.2%}".format(self.goals / self.shots) # '20.45%'
"conversion rate: {:.0%}".format(self.goals / self.shots) # '20%'

"self: {!s}".format(self) # 'Player: Bob'
"self: {!r}".format(self) # '<__main__.Player instance at 0x00BF7260>'

"games: {:>3}".format(player1.games)  # 'games: 123'
"games: {:>3}".format(player2.games)  # 'games:   4'
"games: {:0>3}".format(player2.games) # 'games: 004'

Note: As others pointed out, the new format does not supersede the former, both are available both in Python 3 and the newer versions of Python 2 as well. Some may say it's a matter of preference, but IMHO the newer is much more expressive than the older, and should be used whenever writing new code (unless it's targeting older environments, of course).

Vuex - passing multiple parameters to mutation

Mutations expect two arguments: state and payload, where the current state of the store is passed by Vuex itself as the first argument and the second argument holds any parameters you need to pass.

The easiest way to pass a number of parameters is to destruct them:

mutations: {
    authenticate(state, { token, expiration }) {
        localStorage.setItem('token', token);
        localStorage.setItem('expiration', expiration);
    }
}

Then later on in your actions you can simply

store.commit('authenticate', {
    token,
    expiration,
});

Maximum Length of Command Line String

Sorry for digging out an old thread, but I think sunetos' answer isn't correct (or isn't the full answer). I've done some experiments (using ProcessStartInfo in c#) and it seems that the 'arguments' string for a commandline command is limited to 2048 characters in XP and 32768 characters in Win7. I'm not sure what the 8191 limit refers to, but I haven't found any evidence of it yet.

Given an RGB value, how do I create a tint (or shade)?

Among several options for shading and tinting:

  • For shades, multiply each component by 1/4, 1/2, 3/4, etc., of its previous value. The smaller the factor, the darker the shade.

  • For tints, calculate (255 - previous value), multiply that by 1/4, 1/2, 3/4, etc. (the greater the factor, the lighter the tint), and add that to the previous value (assuming each.component is a 8-bit integer).

Note that color manipulations (such as tints and other shading) should be done in linear RGB. However, RGB colors specified in documents or encoded in images and video are not likely to be in linear RGB, in which case a so-called inverse transfer function needs to be applied to each of the RGB color's components. This function varies with the RGB color space. For example, in the sRGB color space (which can be assumed if the RGB color space is unknown), this function is roughly equivalent to raising each sRGB color component (ranging from 0 through 1) to a power of 2.2. (Note that "linear RGB" is not an RGB color space.)

See also Violet Giraffe's comment about "gamma correction".

Stacking DIVs on top of each other?

Position the outer div however you want, then position the inner divs using absolute. They'll all stack up.

_x000D_
_x000D_
.inner {_x000D_
  position: absolute;_x000D_
}
_x000D_
<div class="outer">_x000D_
   <div class="inner">1</div>_x000D_
   <div class="inner">2</div>_x000D_
   <div class="inner">3</div>_x000D_
   <div class="inner">4</div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

When to use StringBuilder in Java

Some compilers may not replace any string concatenations with StringBuilder equivalents. Be sure to consider which compilers your source will use before relying on compile time optimizations.

How can I change the image displayed in a UIImageView programmatically?

Don't forget to call sizeToFit() after you change image if you then use size of UIImageView to set UIScrollView contentSize and/or compute zoom scale

let image = UIImage(named: "testImage")
imageView.image = image
imageView.sizeToFit()
scrollView.contentSize = imageView.bounds.size

Why powershell does not run Angular commands?

I solved my problem by running below command

Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser

How to get data from Magento System Configuration

$configValue = Mage::getStoreConfig('sectionName/groupName/fieldName');

sectionName, groupName and fieldName are present in etc/system.xml file of your module.

The above code will automatically fetch config value of currently viewed store.

If you want to fetch config value of any other store than the currently viewed store then you can specify store ID as the second parameter to the getStoreConfig function as below:

$store = Mage::app()->getStore(); // store info
$configValue = Mage::getStoreConfig('sectionName/groupName/fieldName', $store);

Select mysql query between date?

select * from *table_name* where *datetime_column* between '01/01/2009' and curdate()

or using >= and <= :

select * from *table_name* where *datetime_column* >= '01/01/2009' and *datetime_column* <= curdate()

Asynchronous vs synchronous execution, what does it really mean?

Simply said asynchronous execution is doing stuff in the background.

For example if you want to download a file from the internet you might use a synchronous function to do that but it will block your thread until the file finished downloading. This can make your application unresponsive to any user input.

Instead you could download the file in the background using asynchronous method. In this case the download function returns immediately and program execution continues normally. All the download operations are done in the background and your program will be notified when it's finished.

How to generate UL Li list from string array using jquery?

    <script type="text/javascript" >
        function aa()
        {
            var YourArray = ['United States', 'Canada', 'Argentina', 'Armenia'];
            var ObjUl = $('<ul></ul>');
            for (i = 0; i < YourArray.length; i++)
            {
                var Objli = $('<li></li>');
                var Obja = $('<a></a>');

                ObjUl.addClass("ui-menu-item");
                ObjUl.attr("role", "menuitem");

                Obja.addClass("ui-all");
                Obja.attr("tabindex", "-1");

                Obja.text(YourArray[i]);
                Objli.append(Obja);

                ObjUl.append(Objli);
            }
            $('.DivSai').append(ObjUl);
        }
    </script>
</head>
<body onload="aa()">
    <form id="form1" runat="server">
    <div class="DivSai" >

    </div>
    </form>
</body>

Best way to remove from NSMutableArray while iterating?

Nowadays you can use reversed block-based enumeration. A simple example code:

NSMutableArray *array = [@[@{@"name": @"a", @"shouldDelete": @(YES)},
                           @{@"name": @"b", @"shouldDelete": @(NO)},
                           @{@"name": @"c", @"shouldDelete": @(YES)},
                           @{@"name": @"d", @"shouldDelete": @(NO)}] mutableCopy];

[array enumerateObjectsWithOptions:NSEnumerationReverse usingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
    if([obj[@"shouldDelete"] boolValue])
        [array removeObjectAtIndex:idx];
}];

Result:

(
    {
        name = b;
        shouldDelete = 0;
    },
    {
        name = d;
        shouldDelete = 0;
    }
)

another option with just one line of code:

[array filterUsingPredicate:[NSPredicate predicateWithFormat:@"shouldDelete == NO"]];

Which Java library provides base64 encoding/decoding?

Java 9

Use the Java 8 solution. Note DatatypeConverter can still be used, but it is now within the java.xml.bind module which will need to be included.

module org.example.foo {
    requires java.xml.bind;
}

Java 8

Java 8 now provides java.util.Base64 for encoding and decoding base64.

Encoding

byte[] message = "hello world".getBytes(StandardCharsets.UTF_8);
String encoded = Base64.getEncoder().encodeToString(message);
System.out.println(encoded);
// => aGVsbG8gd29ybGQ=

Decoding

byte[] decoded = Base64.getDecoder().decode("aGVsbG8gd29ybGQ=");
System.out.println(new String(decoded, StandardCharsets.UTF_8));
// => hello world

Java 6 and 7

Since Java 6 the lesser known class javax.xml.bind.DatatypeConverter can be used. This is part of the JRE, no extra libraries required.

Encoding

byte[] message = "hello world".getBytes("UTF-8");
String encoded = DatatypeConverter.printBase64Binary(message);
System.out.println(encoded);
// => aGVsbG8gd29ybGQ=  

Decoding

byte[] decoded = DatatypeConverter.parseBase64Binary("aGVsbG8gd29ybGQ=");
System.out.println(new String(decoded, "UTF-8"));
// => hello world

New lines (\r\n) are not working in email body

Using <BR> is not allways enough. MS Outlook 2007 will ignore this if you dont tell outlook that it is a selfclosing html tag by using

 <BR />

How to set text color in submit button?

_x000D_
_x000D_
.button_x000D_
{_x000D_
    font-size: 13px;_x000D_
    color:green;_x000D_
}
_x000D_
<input type="submit" value="Fetch" class="button"/>
_x000D_
_x000D_
_x000D_

Trees in Twitter Bootstrap

Can you believe that the treeview on the image below does not use any JavaScript, but relies only on CSS3? Check out this CSS3 TreeView, which is good with Twitter BootStrap:

TreeView

You can get more info about this here http://acidmartin.wordpress.com/2011/09/26/css3-treevew-no-javascript/.

Default settings Raspberry Pi /etc/network/interfaces

Assuming that you have a DHCP server running at your router I would use:

# /etc/network/interfaces
auto lo eth0
iface lo inet loopback

iface eth0 inet dhcp

After changing the file issue (as root):

/etc/init.d/networking restart

Copying one structure to another

If the structures are of compatible types, yes, you can, with something like:

memcpy (dest_struct, source_struct, sizeof (*dest_struct));

The only thing you need to be aware of is that this is a shallow copy. In other words, if you have a char * pointing to a specific string, both structures will point to the same string.

And changing the contents of one of those string fields (the data that the char * points to, not the char * itself) will change the other as well.

If you want a easy copy without having to manually do each field but with the added bonus of non-shallow string copies, use strdup:

memcpy (dest_struct, source_struct, sizeof (*dest_struct));
dest_struct->strptr = strdup (source_struct->strptr);

This will copy the entire contents of the structure, then deep-copy the string, effectively giving a separate string to each structure.

And, if your C implementation doesn't have a strdup (it's not part of the ISO standard), get one from here.

EPPlus - Read Excel Table

Working solution with validate email,mobile number

 public class ExcelProcessing
        {
            public List<ExcelUserData> ReadExcel()
            {
                string path = Config.folderPath + @"\MemberUploadFormat.xlsx";
    
                using (var excelPack = new ExcelPackage())
                {
                    //Load excel stream
                    using (var stream = File.OpenRead(path))
                    {
                        excelPack.Load(stream);
                    }
    
                    //Lets Deal with first worksheet.(You may iterate here if dealing with multiple sheets)
                    var ws = excelPack.Workbook.Worksheets[0];
    
                    List<ExcelUserData> userList = new List<ExcelUserData>();
    
                    int colCount = ws.Dimension.End.Column;  //get Column Count
                    int rowCount = ws.Dimension.End.Row;
                       
                    for (int row = 2; row <= rowCount; row++) // start from to 2 omit header
                    {
                       
                        bool IsValid = true;
                        ExcelUserData _user = new ExcelUserData();
    
                        for (int col = 1; col <= colCount; col++)
                        {
                            if (col == 1)
                            {
                                _user.FirstName = ws.Cells[row, col].Value?.ToString().Trim();
                                if (string.IsNullOrEmpty(_user.FirstName))
                                {
                                    _user.ErrorMessage += "Enter FirstName <br/>";
                                    IsValid = false;
                                }
                            }
                            else if (col == 2)
                            {
                                _user.Email = ws.Cells[row, col].Value?.ToString().Trim();
    
                                if (string.IsNullOrEmpty(_user.Email))
                                {
                                    _user.ErrorMessage += "Enter Email <br/>";
                                    IsValid = false;
                                }
                                else if (!IsValidEmail(_user.Email))
                                {
                                    _user.ErrorMessage += "Invalid Email Address <br/>";
                                    IsValid = false;
                                }
                            }
                            else if (col ==3)
                            {
                                _user.MobileNo = ws.Cells[row, col].Value?.ToString().Trim();
    
                                if (string.IsNullOrEmpty(_user.MobileNo))
                                {
                                    _user.ErrorMessage += "Enter Mobile No <br/>";
                                    IsValid = false;
                                }
                                else if (_user.MobileNo.Length != 10)
                                {
                                    _user.ErrorMessage += "Invalid Mobile No <br/>";
                                    IsValid = false;
                                }
    
                            }
                            else if (col == 4)
                            {
                                _user.IsAdmin = ws.Cells[row, col].Value?.ToString().Trim();
    
                                if (string.IsNullOrEmpty(_user.IsAdmin))
                                {
                                    _user.IsAdmin = "0";
                                }
                            }
    
                            _user.IsValid = IsValid;
                        }
                        userList.Add(_user);
                    }
                    return userList;
                }
            }
            public static bool IsValidEmail(string email)
            {
                Regex regex = new Regex(@"^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$",
                 RegexOptions.CultureInvariant | RegexOptions.Singleline);
    
                return regex.IsMatch(email);
            }
        }

How to change the name of an iOS app?

The best way I like in xcode5 is to change product name in building settings. Search "product name" in "building settings", and change it.

enter image description here

if variable contains

The fastest way to check if a string contains another string is using indexOf:

if (code.indexOf('ST1') !== -1) {
    // string code has "ST1" in it
} else {
    // string code does not have "ST1" in it
}

What is the return value of os.system() in Python?

os.system() returns some unix output, not the command output. So, if there is no error then exit code written as 0.

Fastest way to get the first object from a queryset in django?

If you plan to get first element often - you can extend QuerySet in this direction:

class FirstQuerySet(models.query.QuerySet):
    def first(self):
        return self[0]


class ManagerWithFirstQuery(models.Manager):
    def get_query_set(self):
        return FirstQuerySet(self.model)

Define model like this:

class MyModel(models.Model):
    objects = ManagerWithFirstQuery()

And use it like this:

 first_object = MyModel.objects.filter(x=100).first()

Configure Log4Net in web application

Another way to do this would be to add this line to the assembly info of the web application:

// Configure log4net using the .config file
[assembly: log4net.Config.XmlConfigurator(Watch = true)]

Similar to Shriek's.

How do I remove blank pages coming between two chapters in Appendix?

I tried Noah's suggestion which leads to the best solution up to now.

Just insert \let\cleardoublepage\clearpage before all the parts with the blank pages Especially when you use \documentclass[12pt,a4paper]{book}

frederic snyers's advice \documentclass[oneside]{book} is also very good and solves the problem, but if we just want to use the book.cls or article.cls, the one would make a big difference presenting your particles.

Hence, Big support to \let\cleardoublepage\clearpage for the people who will ask the same question in the future.

Error QApplication: no such file or directory

Well, It's a bit late for this but I've just started learning Qt and maybe this could help somebody out there:

If you're using Qt Creator then when you've started creating the project you were asked to choose a kit to be used with your project, Let's say you chose Desktop Qt <version-here> MinGW 64-bit. For Qt 5, If you opened the Qt folder of your installation, you'll find a folder with the version of Qt installed as its name inside it, here you can find the kits you can choose from.

You can go to /PATH/FOR/Qt/mingw<version>_64/include and here you'll find all the includes you can use in your program, just search for QApplication and you'll find it inside the folder QtWidgets, So you can use #include <QtWidgets/QApplication> since the path starts from the include folder.

The same goes for other headers if you're stuck with any and for other kits.

Note: "all the includes you can use" doesn't mean these are the only ones you can use, If you include iostream for example then the compiler will include it from /PATH/FOR/Qt/Tools/mingw<version>_64/lib/gcc/x86_64-w64-mingw32/7.3.0/include/c++/iostream

How to specify test directory for mocha?

If in node.js, some new configurations as of Mocha v6:

Option 1: Create .mocharc.json in project's root directory:

{
  "spec": "path/to/test/files"
}

Option 2: add mocha property in project's package.json:

{
  ...

  "mocha": {
    "spec": "path/to/test/files"
  }
}

More options are here.

ASP.NET MVC3 Razor - Html.ActionLink style

Reviving an old question because it seems to appear at the top of search results.

I wanted to retain transition effects while still being able to style the actionlink so I came up with this solution.

  1. I wrapped the action link with a div that would contain the parent style:
<div class="parent-style-one">
      @Html.ActionLink("Homepage", "Home", "Home")
</div>
  1. Next I create the CSS for the div, this will be the parent css and will be inherited by the child elements such as the action link.
  .parent-style-one {
     /* your styles here */
  }
  1. Because all an action link is, is an element when broken down as html so you just need to target that element in your css selection:
  .parent-style-one a {
     text-decoration: none;
  }
  1. For transition effects I did this:
  .parent-style-one a:hover {
        text-decoration: underline;
        -webkit-transition-duration: 1.1s; /* Safari */
        transition-duration: 1.1s;         
  }

This way I only target the child elements of the div in this case the action link and still be able to apply transition effects.

How do I set up a private Git repository on GitHub? Is it even possible?

Since January 7th, 2019, it is possible: unlimited free private repositories on GitHub!
... But for up to three collaborators per private repository.

Nat Friedman just announced it by twitter:

Today(!) we’re thrilled to announce unlimited free private repos for all GitHub users, and a new simplified Enterprise offering:

"New year, new GitHub: Announcing unlimited free private repos and unified Enterprise offering"

For the first time, developers can use GitHub for their private projects with up to three collaborators per repository for free.

Many developers want to use private repos to apply for a job, work on a side project, or try something out in private before releasing it publicly.
Starting today, those scenarios, and many more, are possible on GitHub at no cost.

Public repositories are still free (of course—no changes there) and include unlimited collaborators.

How to set the part of the text view is clickable

For bold,

mySpannable.setSpan(new StyleSpan(Typeface.BOLD),termStart,termStop,Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);

How to get the return value from a thread in python?

Another solution that doesn't require changing your existing code:

import Queue             # Python 2.x
#from queue import Queue # Python 3.x

from threading import Thread

def foo(bar):
    print 'hello {0}'.format(bar)
    return 'foo'

que = Queue.Queue()      # Python 2.x
#que = Queue()           # Python 3.x

t = Thread(target=lambda q, arg1: q.put(foo(arg1)), args=(que, 'world!'))
t.start()
t.join()
result = que.get()
print result

It can be also easily adjusted to a multi-threaded environment:

import Queue             # Python 2.x
#from queue import Queue # Python 3.x
from threading import Thread

def foo(bar):
    print 'hello {0}'.format(bar)
    return 'foo'

que = Queue.Queue()      # Python 2.x
#que = Queue()           # Python 3.x

threads_list = list()

t = Thread(target=lambda q, arg1: q.put(foo(arg1)), args=(que, 'world!'))
t.start()
threads_list.append(t)

# Add more threads here
...
threads_list.append(t2)
...
threads_list.append(t3)
...

# Join all the threads
for t in threads_list:
    t.join()

# Check thread's return value
while not que.empty():
    result = que.get()
    print result

How to change the style of a DatePicker in android?

Calendar calendar = Calendar.getInstance();

DatePickerDialog datePickerDialog = new DatePickerDialog(getActivity(), R.style.DatePickerDialogTheme, new DatePickerDialog.OnDateSetListener() {
  public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
    Calendar newDate = Calendar.getInstance();
    newDate.set(year, monthOfYear, dayOfMonth);

    SimpleDateFormat simpleDateFormat = new SimpleDateFormat("dd-MM-yyyy");
    String date = simpleDateFormat.format(newDate.getTime());
  }
}, calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH), calendar.get(Calendar.DAY_OF_MONTH));

datePickerDialog.show();

And use this style:

<style name="DatePickerDialogTheme" parent="Theme.AppCompat.Light.Dialog">
  <item name="colorAccent">@color/colorPrimary</item>
</style>

How do I send a JSON string in a POST request in Go

I'm not familiar with napping, but using Golang's net/http package works fine (playground):

func main() {
    url := "http://restapi3.apiary.io/notes"
    fmt.Println("URL:>", url)

    var jsonStr = []byte(`{"title":"Buy cheese and bread for breakfast."}`)
    req, err := http.NewRequest("POST", url, bytes.NewBuffer(jsonStr))
    req.Header.Set("X-Custom-Header", "myvalue")
    req.Header.Set("Content-Type", "application/json")

    client := &http.Client{}
    resp, err := client.Do(req)
    if err != nil {
        panic(err)
    }
    defer resp.Body.Close()

    fmt.Println("response Status:", resp.Status)
    fmt.Println("response Headers:", resp.Header)
    body, _ := ioutil.ReadAll(resp.Body)
    fmt.Println("response Body:", string(body))
}

How to delete items from a dictionary while iterating over it?

Iterate over a copy instead, such as the one returned by items():

for k, v in list(mydict.items()):

Can't load AMD 64-bit .dll on a IA 32-bit platform

Uninstall(delete) this: jre, jdk, eclipse. Download 32 bit(x86) version of this programs:jre, jdk, eclipse. And install it.

How do I change db schema to dbo

ALTER SCHEMA dbo TRANSFER jonathan.MovieData;

See ALTER SCHEMA.

Generalized Syntax:

ALTER SCHEMA TargetSchema TRANSFER SourceSchema.TableName; 

How to check if all of the following items are in a list?

What if your lists contain duplicates like this:

v1 = ['s', 'h', 'e', 'e', 'p']
v2 = ['s', 's', 'h']

Sets do not contain duplicates. So, the following line returns True.

set(v2).issubset(v1)

To count for duplicates, you can use the code:

v1 = sorted(v1)
v2 = sorted(v2)


def is_subseq(v2, v1):
    """Check whether v2 is a subsequence of v1."""
    it = iter(v1)
    return all(c in it for c in v2) 

So, the following line returns False.

is_subseq(v2, v1)

Setting the selected value on a Django forms.ChoiceField

Both Tom and Burton's answers work for me eventually, but I had a little trouble figuring out how to apply them to a ModelChoiceField.

The only trick to it is that the choices are stored as tuples of (<model's ID>, <model's unicode repr>), so if you want to set the initial model selection, you pass the model's ID as the initial value, not the object itself or it's name or anything else. Then it's as simple as:

form = EmployeeForm(initial={'manager': manager_employee_id})

Alternatively the initial argument can be ignored in place of an extra line with:

form.fields['manager'].initial = manager_employee_id

Get folder name of the file in Python

os.path.dirname is what you are looking for -

os.path.dirname(r"C:\folder1\folder2\filename.xml")

Make sure you prepend r to the string so that its considered as a raw string.

Demo -

In [46]: os.path.dirname(r"C:\folder1\folder2\filename.xml")
Out[46]: 'C:\\folder1\\folder2'

If you just want folder2 , you can use os.path.basename with the above, Example -

os.path.basename(os.path.dirname(r"C:\folder1\folder2\filename.xml"))

Demo -

In [48]: os.path.basename(os.path.dirname(r"C:\folder1\folder2\filename.xml"))
Out[48]: 'folder2'

Viewing localhost website from mobile device

In additional you should disable your antivirus or manage it to open 80 port on your system.

How to check for Is not Null And Is not Empty string in SQL server?

An index friendly way of doing this is:

where (field is not null and field <> '')

If there aren't many rows or this field isn't indexed, you can use:

 where isnull(field,'') <> ''

Can I start the iPhone simulator without "Build and Run"?

First, add the iOS Simulator to Applications:

ln -s /Developer/Platforms/iPhoneSimulator.platform/Developer/Applications/iPhone\ Simulator.app /Applications/iPhone\ Simulator.app

From there you can open it in Finder or drag it to the launch bar.

Source: http://www.bram.us/2010/05/05/xcode-iphone-simulator-location/

How to add http:// if it doesn't exist in the URL

Try this. It is not watertight1, but it might be good enough:

function addhttp($url) {
    if (!preg_match("@^[hf]tt?ps?://@", $url)) {
        $url = "http://" . $url;
    }
    return $url;
}

1. That is, prefixes like "fttps://" are treated as valid.

Can't drop table: A foreign key constraint fails

Use show create table tbl_name to view the foreign keys

You can use this syntax to drop a foreign key:

ALTER TABLE tbl_name DROP FOREIGN KEY fk_symbol

There's also more information here (see Frank Vanderhallen post): http://dev.mysql.com/doc/refman/5.5/en/innodb-foreign-key-constraints.html

Best Practice: Access form elements by HTML id or name attribute?

Just to add to everything already said, you may access the inputs either with the name or id using preferably the elements property of the Object form, because without it you may get a property of the form named "foo" rather than an HTML element. And according to @Paul D. Waite it's perfectly ok to have both name and id.

_x000D_
_x000D_
var myForm = document.getElementById("myform")_x000D_
console.log(myForm.foo.value) // hey_x000D_
console.log(myForm.foo2.value) // hey_x000D_
//preferable_x000D_
console.log(myForm.elements.foo.value) // hey_x000D_
console.log(myForm.elements.foo2.value) // hey
_x000D_
<form id="myform">_x000D_
  <input type="text" name="foo" id="foo2" value="hey">_x000D_
</form>
_x000D_
_x000D_
_x000D_

According to MDN on the HTMLFormElement.elements page

The HTMLFormElement property elements returns an HTMLFormControlsCollection listing all the form controls contained in the element. Independently, you can obtain just the number of form controls using the length property.

You can access a particular form control in the returned collection by using either an index or the element's name or id.

VB.NET - Remove a characters from a String

The string class's Replace method can also be used to remove multiple characters from a string:

Dim newstring As String
newstring = oldstring.Replace(",", "").Replace(";", "")

How to paste yanked text into the Vim command line

  1. "[a-z]y: Copy text to the [a-z] register

  2. Use :! to go to the edit command

  3. Ctrl + R: Follow the register identity to paste what you copy.

It used to CentOS 7.

Regex that accepts only numbers (0-9) and NO characters

Your regex ^[0-9] matches anything beginning with a digit, including strings like "1A". To avoid a partial match, append a $ to the end:

^[0-9]*$

This accepts any number of digits, including none. To accept one or more digits, change the * to +. To accept exactly one digit, just remove the *.

UPDATE: You mixed up the arguments to IsMatch. The pattern should be the second argument, not the first:

if (!System.Text.RegularExpressions.Regex.IsMatch(textbox.Text, "^[0-9]*$"))

CAUTION: In JavaScript, \d is equivalent to [0-9], but in .NET, \d by default matches any Unicode decimal digit, including exotic fare like ? (Myanmar 2) and ? (N'Ko 9). Unless your app is prepared to deal with these characters, stick with [0-9] (or supply the RegexOptions.ECMAScript flag).

Python os.path.join on Windows

Consent with @georg-

I would say then why we need lame os.path.join- better to use str.join or unicode.join e.g.

sys.path.append('{0}'.join(os.path.dirname(__file__).split(os.path.sep)[0:-1]).format(os.path.sep))

How to code a modulo (%) operator in C/C++/Obj-C that handles negative numbers

I have just noticed that Bjarne Stroustrup labels % as the remainder operator, not the modulo operator.

I would bet that this is its formal name in the ANSI C & C++ specifications, and that abuse of terminology has crept in. Does anyone know this for a fact?

But if this is the case then C's fmodf() function (and probably others) are very misleading. they should be labelled fremf(), etc

How to run PowerShell in CMD

Try just:

powershell.exe -noexit D:\Work\SQLExecutor.ps1 -gettedServerName "MY-PC"

Use jQuery to change an HTML tag?

Once a dom element is created, the tag is immutable, I believe. You'd have to do something like this:

$(this).replaceWith($('<h5>' + this.innerHTML + '</h5>'));

How can I access global variable inside class in Python

It is very simple to make a variable global in a class:

a = 0

class b():
    global a
    a = 10

>>> a
10

PHP how to get value from array if key is in a variable

It should work the way you intended.

$array = array('value-0', 'value-1', 'value-2', 'value-3', 'value-4', 'value-5' /* … */);
$key = 4;
$value = $array[$key];
echo $value; // value-4

But maybe there is no element with the key 4. If you want to get the fiveth item no matter what key it has, you can use array_slice:

$value = array_slice($array, 4, 1);

Rename a file using Java

import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import static java.nio.file.StandardCopyOption.*;

Path yourFile = Paths.get("path_to_your_file\text.txt");

Files.move(yourFile, yourFile.resolveSibling("text1.txt"));

To replace an existing file with the name "text1.txt":

Files.move(yourFile, yourFile.resolveSibling("text1.txt"),REPLACE_EXISTING);

How to delete parent element using jQuery

Delete parent:

$(document).on("click", ".remove", function() {
       $(this).parent().remove(); 
});

Delete all parents:

$(document).on("click", ".remove", function() { 
       $(this).parents().remove();
});

delete map[key] in go?

Strangely enough,

package main

func main () {
    var sessions = map[string] chan int{};
    delete(sessions, "moo");
}

seems to work. This seems a poor use of resources though!

Another way is to check for existence and use the value itself:

package main

func main () {
    var sessions = map[string] chan int{};
    sessions["moo"] = make (chan int);
    _, ok := sessions["moo"];
    if ok {
        delete(sessions, "moo");
    }
}

Javascript - Replace html using innerHTML

You are replacing the starting tag and then putting that back in innerHTML, so the code will be invalid. Make all the replacements before you put the code back in the element:

var html = strMessage1.innerHTML;
html = html.replace( /aaaaaa./g,'<a href=\"http://www.google.com/');
html = html.replace( /.bbbbbb/g,'/world\">Helloworld</a>');
strMessage1.innerHTML = html;

Access maven properties defined in the pom

You can parse the pom file with JDOM (http://www.jdom.org/).

How do I return a proper success/error message for JQuery .ajax() using PHP?

Server side:

if (mysql_query($query)) {
    // ...
}
else {
    ajaxError(); 
}

Client side:

error: function() {
    alert("There was an error. Try again please!");
},
success: function(){
    alert("Thank you for subscribing!");
}

How to deal with "data of class uneval" error from ggplot2?

when you add a new data set to a geom you need to use the data= argument. Or put the arguments in the proper order mapping=..., data=.... Take a look at the arguments for ?geom_line.

Thus:

p + geom_line(data=df.last, aes(HrEnd, MWh, group=factor(Date)), color="red") 

Or:

p + geom_line(aes(HrEnd, MWh, group=factor(Date)), df.last, color="red") 

Angular - "has no exported member 'Observable'"

Just put:

import { Observable} from 'rxjs';

Just like that. Nothing more or less.

EC2 instance has no public DNS

  1. Go to AWS Console.
  2. Go to Services and select VPC
  3. Click on vpc.
  4. select the instance and click on Action.
  5. Select Edit DNS Host name click on yes.

At the end you will get your Public dns.

How to set the margin or padding as percentage of height of parent container?

The fix is that yes, vertical padding and margin are relative to width, but top and bottom aren't.

So just place a div inside another, and in the inner div, use something like top:50% (remember position matters if it still doesn't work)

What is "Advanced" SQL?

I would expect:

  • stored procedure creation and usage
  • joins (inner and outer) and how to correctly use GROUP BY
  • performance evaluation/tuning
  • knowledge of efficient (and inefficient) ways of doing things in queries (understanding how certain things can affect performance, e.g. using functions in WHERE clauses)
  • dynamic SQL and knowledge of cursors (and IMO the few times they should be used)
  • understanding of schema design, indexing, and referential integrity

How do I store data in local storage using Angularjs?

Use ngStorage For All Your AngularJS Local Storage Needs. Please note that this is NOT a native part of the Angular JS framework.

ngStorage contains two services, $localStorage and $sessionStorage

angular.module('app', [
   'ngStorage'
]).controller('Ctrl', function(
    $scope,
    $localStorage,
    $sessionStorage
){});

Check the Demo

MySQL: #126 - Incorrect key file for table

Try to use limit in your query. It's because of full disk as said by @Monsters X.

I have also faced this problem and solved by limit in query, because the thousands of records were there. Now working good :)

Date to milliseconds and back to date in Swift

Heres a simple solution in Swift 5/iOS 13.

extension Date {
    
    func toMilliseconds() -> Int64 {
        Int64(self.timeIntervalSince1970 * 1000)
    }

    init(milliseconds:Int) {
        self = Date().advanced(by: TimeInterval(integerLiteral: Int64(milliseconds / 1000)))
    }
}

This however assumes you have calculated the difference between UTF time and local time and adjusted and accounted for in the milliseconds. For that look to calendar

var cal = Calendar.current
cal.timeZone = TimeZone(abbreviation: "UTC")!
let difference = cal.compare(dateGiven, to: date, toGranularity: .nanosecond)

Why am I getting a " Traceback (most recent call last):" error?

I don't know which version of Python you are using but I tried this in Python 3 and made a few changes and it looks like it works. The raw_input function seems to be the issue here. I changed all the raw_input functions to "input()" and I also made minor changes to the printing to be compatible with Python 3. AJ Uppal is correct when he says that you shouldn't name a variable and a function with the same name. See here for reference:

TypeError: 'int' object is not callable

My code for Python 3 is as follows:

# https://stackoverflow.com/questions/27097039/why-am-i-getting-a-traceback-most-recent-call-last-error

raw_input = 0
M = 1.6
# Miles to Kilometers
# Celsius Celsius = (var1 - 32) * 5/9
# Gallons to liters Gallons = 3.6
# Pounds to kilograms Pounds = 0.45
# Inches to centimete Inches = 2.54


def intro():
    print("Welcome! This program will convert measures for you.")
    main()

def main():
    print("Select operation.")
    print("1.Miles to Kilometers")
    print("2.Fahrenheit to Celsius")
    print("3.Gallons to liters")
    print("4.Pounds to kilograms")
    print("5.Inches to centimeters")

    choice = input("Enter your choice by number: ")

    if choice == '1':
        convertMK()

    elif choice == '2':
        converCF()

    elif choice == '3':
        convertGL()

    elif choice == '4':
        convertPK()

    elif choice == '5':
        convertPK()

    else:
        print("Error")


def convertMK():
    input_M = float(input(("Miles: ")))
    M_conv = (M) * input_M
    print("Kilometers: {M_conv}\n")
    restart = str(input("Do you wish to make another conversion? [y]Yes or [n]no: "))
    if restart == 'y':
        main()
    elif restart == 'n':
        end()
    else:
        print("I didn't quite understand that answer. Terminating.")
        main()

def converCF():
    input_F = float(input(("Fahrenheit: ")))
    F_conv = (input_F - 32) * 5/9
    print("Celcius: {F_conv}\n")
    restart = str(input("Do you wish to make another conversion? [y]Yes or [n]no: "))
    if restart == 'y':
        main()
    elif restart == 'n':
        end()
    else:
        print("I didn't quite understand that answer. Terminating.")
        main()

def convertGL():
    input_G = float(input(("Gallons: ")))
    G_conv = input_G * 3.6
    print("Centimeters: {G_conv}\n")
    restart = str(input("Do you wish to make another conversion? [y]Yes or [n]no: "))
    if restart == 'y':
        main()
    elif restart == 'n':
        end()
    else:
        print ("I didn't quite understand that answer. Terminating.")
        main()

def convertPK():
    input_P = float(input(("Pounds: ")))
    P_conv = input_P * 0.45
    print("Centimeters: {P_conv}\n")
    restart = str(input("Do you wish to make another conversion? [y]Yes or [n]no: "))
    if restart == 'y':
        main()
    elif restart == 'n':
        end()
    else:
        print ("I didn't quite understand that answer. Terminating.")
        main()

def convertIC():
    input_cm = float(input(("Inches: ")))
    inches_conv = input_cm * 2.54
    print("Centimeters: {inches_conv}\n")
    restart = str(input("Do you wish to make another conversion? [y]Yes or [n]no: "))
    if restart == 'y':
        main()
    elif restart == 'n':
        end()
    else:
        print ("I didn't quite understand that answer. Terminating.")
        main()

def end():
    print("This program will close.")
    exit()

intro()

I noticed a small bug in your code as well. This function should ideally convert pounds to kilograms but it looks like when it prints, it is printing "Centimeters" instead of kilograms.

def convertPK():
    input_P = float(input(("Pounds: ")))
    P_conv = input_P * 0.45
    # Printing error in the line below
    print("Centimeters: {P_conv}\n")
    restart = str(input("Do you wish to make another conversion? [y]Yes or [n]no: "))
    if restart == 'y':
        main()
    elif restart == 'n':
        end()
    else:
        print ("I didn't quite understand that answer. Terminating.")
        main()

I hope this helps.

An explicit value for the identity column in table can only be specified when a column list is used and IDENTITY_INSERT is ON SQL Server

I use the following to create a temp exact as the table but without the identity:

SELECT TOP 0 CONVERT(INT,0)myid,* INTO #temp FROM originaltable

ALTER TABLE #temp DROP COLUMN id

EXEC tempdb.sys.sp_rename N'#temp.myid', N'id', N'COLUMN'

Gets a warning about renames but no big deal. I use this on production class systems. Helps make sure the copy will follow any future table modifications and the temp produced is capable of getting rows additional times within a task. Please note that the PK constraint is also removed - if you need it you can add it at the end.

Jquery validation plugin - TypeError: $(...).validate is not a function

You're not loading the validation plugin. You need:

<script src="http://ajax.aspnetcdn.com/ajax/jquery.validate/1.11.1/jquery.validate.min.js"></script>

Put this before the line that loads the additional methods.

Also, you should get the additional methods from the CDN as well, rather than jquery.bassistance.de.

Other errors:

[4.20]

should be

[4,20]

and

rangelenght:

should be:

rangelength:

Convert String to java.util.Date

You should set a TimeZone in your DateFormat, otherwise it will use the default one (depending on the settings of the computer).

How to specify multiple return types using type-hints

Python 3.10 (use |): Example for a function which takes a single argument that is either an int or str and returns either an int or str:

def func(arg: int | str) -> int | str:
              ^^^^^^^^^     ^^^^^^^^^ 
             type of arg   return type

Python 3.5 - 3.9 (use typing.Union):

from typing import Union
def func(arg: Union[int, str]) -> Union[int, str]:
              ^^^^^^^^^^^^^^^     ^^^^^^^^^^^^^^^ 
                type of arg         return type

For the special case of X | None you can use Optional[X].

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.

Set selected item of spinner programmatically

Some explanation (at least for Fragments - never tried with pure Activity). Hope it helps someone to understand Android better.

Most popular answer by Arun George is correct but don't work in some cases.
The answer by Marco HC uses Runnable wich is a last resort due to additional CPU load.

The answer is - you should simply choose correct place to call to setSelection(), for example it works for me:

@Override
public void onResume() {
    super.onResume();

    yourSpinner.setSelection(pos);
 }

But it won't work in onCreateView(). I suspect that is the reason for the interest to this topic.

The secret is that with Android you can't do anything you want in any method - oops:( - components may just not be ready. As another example - you can't scroll ScrollView neither in onCreateView() nor in onResume() (see the answer here)

"Call to undefined function mysql_connect()" after upgrade to php-7

From the PHP Manual:

Warning This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0. Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide. Alternatives to this function include:

mysqli_connect()

PDO::__construct()

use MySQLi or PDO

<?php
$con = mysqli_connect('localhost', 'username', 'password', 'database');

How do I install package.json dependencies in the current directory using npm

Running:

npm install

from inside your app directory (i.e. where package.json is located) will install the dependencies for your app, rather than install it as a module, as described here. These will be placed in ./node_modules relative to your package.json file (it's actually slightly more complex than this, so check the npm docs here).

You are free to move the node_modules dir to the parent dir of your app if you want, because node's 'require' mechanism understands this. However, if you want to update your app's dependencies with install/update, npm will not see the relocated 'node_modules' and will instead create a new dir, again relative to package.json.

To prevent this, just create a symlink to the relocated node_modules from your app dir:

ln -s ../node_modules node_modules

phpinfo() is not working on my CentOS server

Be sure that the tag "php" is stick in the code like this:

?php phpinfo(); ?>

Not like this:

? php phpinfo(); ?>

OR the server will treat it as a (normal word), so the server will not understand the language you are writing to deal with it so it will be blank.

I know it's a silly error ...but it happened ^_^

HTML - Arabic Support

Check you have <meta charset="utf-8"> inside head block.

Ruby: How to get the first character of a string

Try this:

>> a = "Smith"
>> a[0]
=> "S"

OR

>> "Smith".chr
#=> "S"

What is the best way to remove a table row with jQuery?

If you are using Bootstrap Tables

add this code snippet to your bootstrap_table.js

BootstrapTable.prototype.removeRow = function (params) {
    if (!params.hasOwnProperty('index')) {
        return;
    }

    var len = this.options.data.length;

    if ((params.index > len) || (params.index < 0)){
        return;
    }

    this.options.data.splice(params.index, 1);

    if (len === this.options.data.length) {
        return;
    }

    this.initSearch();
    this.initPagination();
    this.initBody(true);
};

Then in your var allowedMethods = [

add 'removeRow'

Finally you can use $("#your-table").bootstrapTable('removeRow',{index:1});

Credits to this post

Include jQuery in the JavaScript Console

Turnkey solution :

Put your code in yourCode_here function. And prevent HTML without HEAD tag.

_x000D_
_x000D_
(function(head) {_x000D_
  var jq = document.createElement('script');_x000D_
  jq.src = "https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js";_x000D_
  ((head && head[0]) || document.firstChild).appendChild(jq);_x000D_
})(document.getElementsByTagName('head'));_x000D_
_x000D_
function jQueryReady() {_x000D_
  if (window.jQuery) {_x000D_
    jQuery.noConflict();_x000D_
    yourCode_here(jQuery);_x000D_
  } else {_x000D_
    setTimeout(jQueryReady, 100);_x000D_
  }_x000D_
}_x000D_
_x000D_
jQueryReady();_x000D_
_x000D_
function yourCode_here($) {_x000D_
  console.log("OK");_x000D_
  $("body").html("<h1>Hello world !</h1>");_x000D_
}
_x000D_
_x000D_
_x000D_

Regex Letters, Numbers, Dashes, and Underscores

Just escape the dashes to prevent them from being interpreted (I don't think underscore needs escaping, but it can't hurt). You don't say which regex you are using.

([A-Za-z0-9\-\_]+)

The type java.util.Map$Entry cannot be resolved. It is indirectly referenced from required .class files

I've seen occasional problems with Eclipse forgetting that built-in classes (including Object and String) exist. The way I've resolved them is to:

  • On the Project menu, turn off "Build Automatically"
  • Quit and restart Eclipse
  • On the Project menu, choose "Clean…" and clean all projects
  • Turn "Build Automatically" back on and let it rebuild everything.

This seems to make Eclipse forget whatever incorrect cached information it had about the available classes.

How to remove gaps between subplots in matplotlib?

Without resorting gridspec entirely, the following might also be used to remove the gaps by setting wspace and hspace to zero:

import matplotlib.pyplot as plt

plt.clf()
f, axarr = plt.subplots(4, 4, gridspec_kw = {'wspace':0, 'hspace':0})

for i, ax in enumerate(f.axes):
    ax.grid('on', linestyle='--')
    ax.set_xticklabels([])
    ax.set_yticklabels([])

plt.show()
plt.close()

Resulting in:

.

Using NOT operator in IF conditions

It really depends on what you're trying to accomplish. If you have no else clause then if(!doSomething()) seems fine. However, if you have

if(!doSomething()) {
    ...
}
else {
    // do something else
}

I'd probably reverse that logic to remove the ! operator and make the if clause slightly more clear.

Flutter command not found

The best way to setup Flutter on Mac

    1. Open a new terminal window
    2. Type: git clone https://github.com/flutter/flutter.git -b stable
       Wait for the SDK to clone onto your machine
    3. Type: export PATH="$PATH:`pwd`/flutter/bin", which adds flutter tool to your path
    4. Type: flutter doctor , which downloads additional dependencies

    Wait for dependencies to download and install

Import Excel spreadsheet columns into SQL Server database

First of all, try the 32 Bit Version of the Import Wizard. This shows a lot more supported import formats.

Background: All depends on your Office (Runtimes Engines) installation.

If you dont't have Office 2007 or greater installed, the Import Wizard (32 Bit) only allows you to import Excel 97-2003 (.xls) files.

If you have the Office 2010 and geater (comes also in 64 Bit, not recommended) installed, the Import Wizard also supports Excel 2007+ (.xlsx) files.

To get an overview on the runtimes see 'Microsoft.ACE.OLEDB.12.0' provider is not registered on the local machine

How do you put an image file in a json object?

I can think of doing it in two ways:

1.

Storing the file in file system in any directory (say dir1) and renaming it which ensures that the name is unique for every file (may be a timestamp) (say xyz123.jpg), and then storing this name in some DataBase. Then while generating the JSON you pull this filename and generate a complete URL (which will be http://example.com/dir1/xyz123.png )and insert it in the JSON.

2.

Base 64 Encoding, It's basically a way of encoding arbitrary binary data in ASCII text. It takes 4 characters per 3 bytes of data, plus potentially a bit of padding at the end. Essentially each 6 bits of the input is encoded in a 64-character alphabet. The "standard" alphabet uses A-Z, a-z, 0-9 and + and /, with = as a padding character. There are URL-safe variants. So this approach will allow you to put your image directly in the MongoDB, while storing it Encode the image and decode while fetching it, it has some of its own drawbacks:

  • base64 encoding makes file sizes roughly 33% larger than their original binary representations, which means more data down the wire (this might be exceptionally painful on mobile networks)
  • data URIs aren’t supported on IE6 or IE7.
  • base64 encoded data may possibly take longer to process than binary data.

Source

Converting Image to DATA URI

A.) Canvas

Load the image into an Image-Object, paint it to a canvas and convert the canvas back to a dataURL.

function convertToDataURLviaCanvas(url, callback, outputFormat){
    var img = new Image();
    img.crossOrigin = 'Anonymous';
    img.onload = function(){
        var canvas = document.createElement('CANVAS');
        var ctx = canvas.getContext('2d');
        var dataURL;
        canvas.height = this.height;
        canvas.width = this.width;
        ctx.drawImage(this, 0, 0);
        dataURL = canvas.toDataURL(outputFormat);
        callback(dataURL);
        canvas = null; 
    };
    img.src = url;
}

Usage

convertToDataURLviaCanvas('http://bit.ly/18g0VNp', function(base64Img){
    // Base64DataURL
});

Supported input formats image/png, image/jpeg, image/jpg, image/gif, image/bmp, image/tiff, image/x-icon, image/svg+xml, image/webp, image/xxx

B.) FileReader

Load the image as blob via XMLHttpRequest and use the FileReader API to convert it to a data URL.

function convertFileToBase64viaFileReader(url, callback){
    var xhr = new XMLHttpRequest();
    xhr.responseType = 'blob';
    xhr.onload = function() {
      var reader  = new FileReader();
      reader.onloadend = function () {
          callback(reader.result);
      }
      reader.readAsDataURL(xhr.response);
    };
    xhr.open('GET', url);
    xhr.send();
}

This approach

  • lacks in browser support
  • has better compression
  • works for other file types as well.

Usage

convertFileToBase64viaFileReader('http://bit.ly/18g0VNp', function(base64Img){
    // Base64DataURL
});

Source

Scanner is never closed

I am assuming you are using java 7, thus you get a compiler warning, when you don't close the resource you should close your scanner usually in a finally block.

Scanner scanner = null;
try {
    scanner = new Scanner(System.in);
    //rest of the code
}
finally {
    if(scanner!=null)
        scanner.close();
}

Or even better: use the new Try with resource statement:

try(Scanner scanner = new Scanner(System.in)){
    //rest of your code
}

ORA-00918: column ambiguously defined in SELECT *

You can also see this error when selecting for a union where corresponding columns can be null.

select * from (select D.dept_no, D.nullable_comment
                  from dept D
       union
               select R.dept_no, NULL
                 from redundant_dept R
)

This apparently confuses the parser, a solution is to assign a column alias to the always null column.

select * from (select D.dept_no, D.comment
                  from dept D
       union
               select R.dept_no, NULL "nullable_comment"
                 from redundant_dept R
)

The alias does not have to be the same as the corresponding column, but the column heading in the result is driven by the first query from among the union members, so it's probably a good practice.

Text overwrite in visual studio 2010

If pressing the Insert key doesn't work, try doubleclicking the INS/OVR label in the lower right corner of Visual Studio.

Java; String replace (using regular expressions)?

What is your polynomial? If you're "processing" it, I'm envisioning some sort of tree of sub-expressions being generated at some point, and would think that it would be much simpler to use that to generate your string than to re-parse the raw expression with a regex.

Just throwing a different way of thinking out there. I'm not sure what else is going on in your app.

When do you use varargs in Java?

Varargs can be used when we are unsure about the number of arguments to be passed in a method. It creates an array of parameters of unspecified length in the background and such a parameter can be treated as an array in runtime.

If we have a method which is overloaded to accept different number of parameters, then instead of overloading the method different times, we can simply use varargs concept.

Also when the parameters' type is going to vary then using "Object...test" will simplify the code a lot.

For example:

public int calculate(int...list) {
    int sum = 0;
    for (int item : list) {
        sum += item;
    }
    return sum;
}

Here indirectly an array of int type (list) is passed as parameter and is treated as an array in the code.

For a better understanding follow this link(it helped me a lot in understanding this concept clearly): http://www.javadb.com/using-varargs-in-java

P.S: Even I was afraid of using varargs when I didn't knw abt it. But now I am used to it. As it is said: "We cling to the known, afraid of the unknown", so just use it as much as you can and you too will start liking it :)

Scroll to a div using jquery

you can try :

$("#MediaPlayer").ready(function(){
    $("html, body").delay(2000).animate({
        scrollTop: $('#MediaPlayer').offset().top 
    }, 2000);
});

How to set String's font size, style in Java using the Font class?

Font myFont = new Font("Serif", Font.BOLD, 12);, then use a setFont method on your components like

JButton b = new JButton("Hello World");
b.setFont(myFont);

Tips for using Vim as a Java IDE?

I have just uploaded this Vim plugin for the development of Java Maven projects.

And don't forget to set the highlighting if you haven't already:

enter image description here https://github.com/sentientmachine/erics_vim_syntax_and_color_highlighting

Add an image in a WPF button

In the case of a 'missing' image there are several things to consider:

  1. When XAML can't locate a resource it might ignore it (when it won't throw a XamlParseException)

  2. The resource must be properly added and defined:

    • Make sure it exists in your project where expected.

    • Make sure it is built with your project as a resource.

      (Right click ? Properties ? BuildAction='Resource')

Snippet

Another thing to try in similar cases, which is also useful for reusing of the image (or any other resource):

Define your image as a resource in your XAML:

<UserControl.Resources>
     <Image x:Key="MyImage" Source.../>
</UserControl.Resources>

And later use it in your desired control(s):

<Button Content="{StaticResource MyImage}" />

Java default constructor

Java provides a default constructor which takes no arguments and performs no special actions or initializations, when no explicit constructors are provided.

The only action taken by the implicit default constructor is to call the superclass constructor using the super() call. Constructor arguments provide you with a way to provide parameters for the initialization of an object.

Below is an example of a cube class containing 2 constructors. (one default and one parameterized constructor).

public class Cube1 {
    int length;
    int breadth;
    int height;
    public int getVolume() {
        return (length * breadth * height);
    }

    Cube1() {
        length = 10;
        breadth = 10;
        height = 10;
    }

    Cube1(int l, int b, int h) {
        length = l;
        breadth = b;
        height = h;
    }

    public static void main(String[] args) {
        Cube1 cubeObj1, cubeObj2;
        cubeObj1 = new Cube1();
        cubeObj2 = new Cube1(10, 20, 30);
        System.out.println("Volume of Cube1 is : " + cubeObj1.getVolume());
        System.out.println("Volume of Cube1 is : " + cubeObj2.getVolume());
    }
}

What HTTP status response code should I use if the request is missing a required parameter?

I Usually go for 422 (Unprocessable entity) if something in the required parameters didn't match what the API endpoint required (like a too short password) but for a missing parameter i would go for 406 (Unacceptable).

Background color in input and text fields

You want to restrict to input fields that are of type text so use the selector input[type=text] rather than input (which will apply to all input fields (e.g. those of type submit as well)).

How do I check if a PowerShell module is installed?

When I use a non-default modules in my scripts I call the function below. Beside the module name you can provide a minimum version.

# See https://www.powershellgallery.com/ for module and version info
Function Install-ModuleIfNotInstalled(
    [string] [Parameter(Mandatory = $true)] $moduleName,
    [string] $minimalVersion
) {
    $module = Get-Module -Name $moduleName -ListAvailable |`
        Where-Object { $null -eq $minimalVersion -or $minimalVersion -ge $_.Version } |`
        Select-Object -Last 1
    if ($null -ne $module) {
         Write-Verbose ('Module {0} (v{1}) is available.' -f $moduleName, $module.Version)
    }
    else {
        Import-Module -Name 'PowershellGet'
        $installedModule = Get-InstalledModule -Name $moduleName -ErrorAction SilentlyContinue
        if ($null -ne $installedModule) {
            Write-Verbose ('Module [{0}] (v {1}) is installed.' -f $moduleName, $installedModule.Version)
        }
        if ($null -eq $installedModule -or ($null -ne $minimalVersion -and $installedModule.Version -lt $minimalVersion)) {
            Write-Verbose ('Module {0} min.vers {1}: not installed; check if nuget v2.8.5.201 or later is installed.' -f $moduleName, $minimalVersion)
            #First check if package provider NuGet is installed. Incase an older version is installed the required version is installed explicitly
            if ((Get-PackageProvider -Name NuGet -Force).Version -lt '2.8.5.201') {
                Write-Warning ('Module {0} min.vers {1}: Install nuget!' -f $moduleName, $minimalVersion)
                Install-PackageProvider -Name NuGet -MinimumVersion 2.8.5.201 -Scope CurrentUser -Force
            }        
            $optionalArgs = New-Object -TypeName Hashtable
            if ($null -ne $minimalVersion) {
                $optionalArgs['RequiredVersion'] = $minimalVersion
            }  
            Write-Warning ('Install module {0} (version [{1}]) within scope of the current user.' -f $moduleName, $minimalVersion)
            Install-Module -Name $moduleName @optionalArgs -Scope CurrentUser -Force -Verbose
        } 
    }
}

usage example:

Install-ModuleIfNotInstalled 'CosmosDB' '2.1.3.528'

Please let me known if it's usefull (or not)

Delete files older than 10 days using shell script in Unix

If you can afford working via the file data, you can do

find -mmin +14400 -delete

How to make the overflow CSS property work with hidden as value

This worked for me

<div style="display: flex; position: absolute; width: 100%;">
  <div style="white-space: nowrap; overflow: hidden;text-overflow: ellipsis;">
    Lorem ipsum dolor sit amet, consectetur adipiscing elit. Integer nec odio. Praesent libero. Sed cursus ante dapibus diam. Sed nisi.
  </div>
</div>

Adding position:absolute to the parent container made it work.

PS: This is for anyone looking for a solution to dynamically truncating text.

EDIT: This was meant to be an answer for this question but since they are related and it could help someone on this question I shall also leave it here instead of deleting it.

Excel VBA Run-time error '424': Object Required when trying to copy TextBox

The problem with your macro is that once you have opened your destination Workbook (xlw in your code sample), it is set as the ActiveWorkbook object and you get an error because TextBox1 doesn't exist in that specific Workbook. To resolve this issue, you could define a reference object to your actual Workbook before opening the other one.

Sub UploadData()
    Dim xlo As New Excel.Application
    Dim xlw As New Excel.Workbook
    Dim myWb as Excel.Workbook

    Set myWb = ActiveWorkbook
    Set xlw = xlo.Workbooks.Open("c:\myworkbook.xlsx")
    xlo.Worksheets(1).Cells(2, 1) = myWb.ActiveSheet.Range("d4").Value
    xlo.Worksheets(1).Cells(2, 2) = myWb.ActiveSheet.TextBox1.Text

    xlw.Save
    xlw.Close
    Set xlo = Nothing
    Set xlw = Nothing
End Sub

If you prefer, you could also use myWb.Activate to put back your main Workbook as active. It will also work if you do it with a Worksheet object. Using one or another mostly depends on what you want to do (if there are multiple sheets, etc.).

Return JsonResult from web api without its properties

return JsonConvert.SerializeObject(images.ToList(), Formatting.None, new JsonSerializerSettings { PreserveReferencesHandling = PreserveReferencesHandling.None, ReferenceLoopHandling = ReferenceLoopHandling.Ignore });


using Newtonsoft.Json;

Convert java.util.Date to java.time.LocalDate

public static LocalDate Date2LocalDate(Date date) {
        return LocalDate.parse(date.toString(), DateTimeFormatter.ofPattern("EEE MMM dd HH:mm:ss zzz yyyy"))

this format is from Date#tostring

    public String toString() {
        // "EEE MMM dd HH:mm:ss zzz yyyy";
        BaseCalendar.Date date = normalize();
        StringBuilder sb = new StringBuilder(28);
        int index = date.getDayOfWeek();
        if (index == BaseCalendar.SUNDAY) {
            index = 8;
        }
        convertToAbbr(sb, wtb[index]).append(' ');                        // EEE
        convertToAbbr(sb, wtb[date.getMonth() - 1 + 2 + 7]).append(' ');  // MMM
        CalendarUtils.sprintf0d(sb, date.getDayOfMonth(), 2).append(' '); // dd

        CalendarUtils.sprintf0d(sb, date.getHours(), 2).append(':');   // HH
        CalendarUtils.sprintf0d(sb, date.getMinutes(), 2).append(':'); // mm
        CalendarUtils.sprintf0d(sb, date.getSeconds(), 2).append(' '); // ss
        TimeZone zi = date.getZone();
        if (zi != null) {
            sb.append(zi.getDisplayName(date.isDaylightTime(), TimeZone.SHORT, Locale.US)); // zzz
        } else {
            sb.append("GMT");
        }
        sb.append(' ').append(date.getYear());  // yyyy
        return sb.toString();
    }

Subclipse svn:ignore

I just figured out how to do this:

It appears that when you add a parent folder to version control, Eclipse adds all sub-folders. Once the sub-folders are added to version control, it is not possible to ignore them.

Here's how to do it:

Right click on the top level folder and add to version control Right click on the child folder you want to ignore, revert Right click on the child folder you want to ignore, svn:ignore (which will now be available)

xcopy file, rename, suppress "Does xxx specify a file name..." message

So, there is a simple fix for this. It is admittedly awkward, but it works. xcopy will not prompt to find out if the destination is a directory or file IF the new file(filename) already exists. If you precede your xcopy command with a simple echo to the new filename, it will overwrite the empty file. Example

echo.>newfile.txt
xcopy oldfile.txt newfile.txt /Y

How can I decrypt a password hash in PHP?

I need to decrypt a password. The password is crypted with password_hash function.

$password = 'examplepassword';
$crypted = password_hash($password, PASSWORD_DEFAULT);

Its not clear to me if you need password_verify, or you are trying to gain unauthorized access to the application or database. Other have talked about password_verify, so here's how you could gain unauthorized access. Its what bad guys often do when they try to gain access to a system.

First, create a list of plain text passwords. A plain text list can be found in a number of places due to the massive data breaches from companies like Adobe. Sort the list and then take the top 10,000 or 100,000 or so.

Second, create a list of digested passwords. Simply encrypt or hash the password. Based on your code above, it does not look like a salt is being used (or its a fixed salt). This makes the attack very easy.

Third, for each digested password in the list, perform a select in an attempt to find a user who is using the password:

$sql_script = 'select * from USERS where password="'.$digested_password.'"'

Fourth, profit.

So, rather than picking a user and trying to reverse their password, the bad guy picks a common password and tries to find a user who is using it. Odds are on the bad guy's side...

Because the bad guy does these things, it would behove you to not let users choose common passwords. In this case, take a look at ProCheck, EnFilter or Hyppocrates (et al). They are filtering libraries that reject bad passwords. ProCheck achieves very high compression, and can digest multi-million word password lists into a 30KB data file.

How to replace captured groups only?

A simplier option is to just capture the digits and replace them.

_x000D_
_x000D_
const name = 'preceding_text_0_following_text';_x000D_
const matcher = /(\d+)/;_x000D_
_x000D_
// Replace with whatever you would like_x000D_
const newName = name.replace(matcher, 'NEW_STUFF');_x000D_
console.log("Full replace", newName);_x000D_
_x000D_
// Perform work on the match and replace using a function_x000D_
// In this case increment it using an arrow function_x000D_
const incrementedName = name.replace(matcher, (match) => ++match);_x000D_
console.log("Increment", incrementedName);
_x000D_
_x000D_
_x000D_

Resources

Use .htaccess to redirect HTTP to HTTPs

It works for me:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTPS} !on           
RewriteRule ^(.*) https://%{SERVER_NAME}/$1 [R,L]
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

Ignore self-signed ssl cert using Jersey Client

For Jersey 2.*:

Client client = ClientBuilder.newBuilder()
                .hostnameVerifier(new HostnameVerifier() {
                    @Override
                    public boolean verify(String hostname, SSLSession session) {
                        return true;
                    }
                }).build();

-> https://jersey.java.net/documentation/latest/migration.html

Are string.Equals() and == operator really same?

C# has two "equals" concepts: Equals and ReferenceEquals. For most classes you will encounter, the == operator uses one or the other (or both), and generally only tests for ReferenceEquals when handling reference types (but the string Class is an instance where C# already knows how to test for value equality).

  • Equals compares values. (Even though two separate int variables don't exist in the same spot in memory, they can still contain the same value.)
  • ReferenceEquals compares the reference and returns whether the operands point to the same object in memory.

Example Code:

var s1 = new StringBuilder("str");
var s2 = new StringBuilder("str");
StringBuilder sNull = null;

s1.Equals(s2); // True
object.ReferenceEquals(s1, s2); // False
s1 == s2 // True - it calls Equals within operator overload
s1 == sNull // False
object.ReferenceEquals(s1, sNull); // False
s1.Equals(sNull); // Nono!  Explode (Exception)

How to get method parameter names?

Here is another way to get the function parameters without using any module.

def get_parameters(func):
    keys = func.__code__.co_varnames[:func.__code__.co_argcount][::-1]
    sorter = {j: i for i, j in enumerate(keys[::-1])} 
    values = func.__defaults__[::-1]
    kwargs = {i: j for i, j in zip(keys, values)}
    sorted_args = tuple(
        sorted([i for i in keys if i not in kwargs], key=sorter.get)
    )
    sorted_kwargs = {
        i: kwargs[i] for i in sorted(kwargs.keys(), key=sorter.get)
    }   
    return sorted_args, sorted_kwargs


def f(a, b, c="hello", d="world"): var = a
    

print(get_parameters(f))

Output:

(('a', 'b'), {'c': 'hello', 'd': 'world'})

How to install both Python 2.x and Python 3.x in Windows

To install and run any version of Python in the same system follow my guide below.


For example say you want to install Python 2.x and Python 3.x on the same Windows system.

  1. Install both of their binary releases anywhere you want.

    • When prompted do not register their file extensions and
    • do not add them automatically to the PATH environment variable
  2. Running simply the command python the executable that is first met in PATH will be chosen for launch. In other words, add the Python directories manually. The one you add first will be selected when you type python. Consecutive python programs (increasing order that their directories are placed in PATH) will be chosen like so:

    • py -2 for the second python
    • py -3 for the third python etc..
  3. No matter the order of "pythons" you can:

    • run Python 2.x scripts using the command: py -2 (Python 3.x functionality) (ie. the first Python 2.x installation program found in your PATH will be selected)
    • run Python 3.x scripts using the command: or py -3 (ie. the first Python 3.x installation program found in your PATH will be selected)

In my example I have Python 2.7.14 installed first and Python 3.5.3. This is how my PATH variable starts with:

PATH=C:\Program Files\Microsoft MPI\Bin\;C:\Python27;C:\Program Files\Python_3.6\Scripts\;C:\Program Files\Python_3.6\;C:\ProgramData\Oracle\Java\javapath;C:\Program Files (x86)\Common Files\Intel\Shared

...

Note that Python 2.7 is first and Python 3.5 second.

  • So running python command will launch python 2.7 (if Python 3.5 the same command would launch Python 3.5).
  • Running py -2 launches Python 2.7 (because it happens that the second Python is Python 3.5 which is incompatible with py -2). Running py -3 launches Python 3.5 (because it's Python 3.x)
  • If you had another python later in your path you would launch like so: py -4. This may change if/when Python version 4 is released.

Now py -4 or py -5 etc. on my system outputs: Requested Python version (4) not installed or Requested Python version (5) not installed etc.

Hopefully this is clear enough.

Property 'value' does not exist on type 'EventTarget'

Since I reached two questions searching for my problem in a slightly different way, I am replicating my answer in case you end up here.

In the called function, you can define your type with:

emitWordCount(event: { target: HTMLInputElement }) {
  this.countUpdate.emit(event.target.value);
}

This assumes you are only interested in the target property, which is the most common case. If you need to access the other properties of event, a more comprehensive solution involves using the & type intersection operator:

event: Event & { target: HTMLInputElement }

You can also go more specific and instead of using HTMLInputElement you can use e.g. HTMLTextAreaElement for textareas.

Differences between JDK and Java SDK

From this wikipedia entry:

The JDK is a subset of what is loosely defined as a software development kit (SDK) in the general sense. In the descriptions which accompany their recent releases for Java SE, EE, and ME, Sun acknowledge that under their terminology, the JDK forms the subset of the SDK which is responsible for the writing and running of Java programs. The remainder of the SDK is composed of extra software, such as Application Servers, Debuggers, and Documentation.

The "extra software" seems to be Glassfish, MySQL, and NetBeans. This page gives a comparison of the various packages you can get for the Java EE SDK.

How to add a filter class in Spring Boot?

We have roughly four different options to register a filter using Spring.

Firstly, we can create a Spring bean implementing Filter or extending HttpFilter:

@Component
public class MyFilter extends HttpFilter {

    @Override
    protected void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain) 
        throws IOException, ServletException {
        // Implementation details...

        chain.doFilter(request, response);
    }
}

Secondly, we can create a Spring bean extending GenericFilterBean:

@Component
public class MyFilter extends GenericFilterBean {

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain)
  throws IOException, ServletException {
    //Implementation details...

        chain.doFilter(currentRequest, servletResponse);
    }
}

Alternatively we can use the FilterRegistrationBean class:

@Configuration
public class FilterConfiguration {

    private final MyFilter myFilter;

    @Autowired
    public FilterConfiguration(MyFilter myFilter) {
        this.myFilter = myFilter;
    }

    @Bean
    public FilterRegistrationBean<MyFilter> myFilterRegistration() {
        FilterRegistrationBean<DateLoggingFilter> filterRegistrationBean = new FilterRegistrationBean<>();
        filterRegistrationBean.setFilter(myFilter);
        filterRegistrationBean.setUrlPatterns(Collections.singletonList("/*"));
        filterRegistrationBean.setDispatcherTypes(DispatcherType.REQUEST);
        filterRegistrationBean.setOrder(Ordered.LOWEST_PRECEDENCE - 1);
        return filterRegistrationBean;
    }
}

And lastly we can use the @WebFilter annotation with @ServletComponentScan:

@WebFilter(urlPatterns = "/*", dispatcherTypes = {DispatcherType.REQUEST})
public class MyFilter extends HttpFilter {

    @Override
    protected void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
  throws IOException, ServletException {
        // Implementation details...

        chain.doFilter(request, response);
    }
}

How to upper case every first letter of word in a string?

public class WordChangeInCapital{

   public static void main(String[]  args)
   {
      String s="this is string example";
      System.out.println(s);
      //this is input data.
      //this example for a string where each word must be started in capital letter
      StringBuffer sb=new StringBuffer(s);
      int i=0;
      do{
        b.replace(i,i+1,sb.substring(i,i+1).toUpperCase());
        i=b.indexOf(" ",i)+1;
      } while(i>0 && i<sb.length());
      System.out.println(sb.length());
   }

}

How to insert 1000 rows at a time

Simplest way.

Just stop execution in 10 sec.

Create table SQL_test  ( ID INT IDENTITY(1,1), UserName varchar(100)) 
while 1=1 
insert into SQL_test values ('TEST') 

How to run a class from Jar which is not the Main-Class in its Manifest file

First of all jar creates a jar, and does not run it. Try java -jar instead.

Second, why do you pass the class twice, as FQCN (com.mycomp.myproj.dir2.MainClass2) and as file (com/mycomp/myproj/dir2/MainClass2.class)?

Edit:

It seems as if java -jar requires a main class to be specified. You could try java -cp your.jar com.mycomp.myproj.dir2.MainClass2 ... instead. -cp sets the jar on the classpath and enables java to look up the main class there.

Mocha / Chai expect.to.throw not catching thrown errors

As this answer says, you can also just wrap your code in an anonymous function like this:

expect(function(){
    model.get('z');
}).to.throw('Property does not exist in model schema.');

How to transform numpy.matrix or array to scipy sparse matrix

In Python, the Scipy library can be used to convert the 2-D NumPy matrix into a Sparse matrix. SciPy 2-D sparse matrix package for numeric data is scipy.sparse

The scipy.sparse package provides different Classes to create the following types of Sparse matrices from the 2-dimensional matrix:

  1. Block Sparse Row matrix
  2. A sparse matrix in COOrdinate format.
  3. Compressed Sparse Column matrix
  4. Compressed Sparse Row matrix
  5. Sparse matrix with DIAgonal storage
  6. Dictionary Of Keys based sparse matrix.
  7. Row-based list of lists sparse matrix
  8. This class provides a base class for all sparse matrices.

CSR (Compressed Sparse Row) or CSC (Compressed Sparse Column) formats support efficient access and matrix operations.

Example code to Convert Numpy matrix into Compressed Sparse Column(CSC) matrix & Compressed Sparse Row (CSR) matrix using Scipy classes:

import sys                 # Return the size of an object in bytes
import numpy as np         # To create 2 dimentional matrix
from scipy.sparse import csr_matrix, csc_matrix 
# csr_matrix: used to create compressed sparse row matrix from Matrix
# csc_matrix: used to create compressed sparse column matrix from Matrix

create a 2-D Numpy matrix

A = np.array([[1, 0, 0, 0, 0, 0],\
              [0, 0, 2, 0, 0, 1],\
              [0, 0, 0, 2, 0, 0]])
print("Dense matrix representation: \n", A)
print("Memory utilised (bytes): ", sys.getsizeof(A))
print("Type of the object", type(A))

Print the matrix & other details:

Dense matrix representation: 
 [[1 0 0 0 0 0]
 [0 0 2 0 0 1]
 [0 0 0 2 0 0]]
Memory utilised (bytes):  184
Type of the object <class 'numpy.ndarray'>

Converting Matrix A to the Compressed sparse row matrix representation using csr_matrix Class:

S = csr_matrix(A)
print("Sparse 'row' matrix: \n",S)
print("Memory utilised (bytes): ", sys.getsizeof(S))
print("Type of the object", type(S))

The output of print statements:

Sparse 'row' matrix:
(0, 0) 1
(1, 2) 2
(1, 5) 1
(2, 3) 2
Memory utilised (bytes): 56
Type of the object: <class 'scipy.sparse.csr.csc_matrix'>

Converting Matrix A to Compressed Sparse Column matrix representation using csc_matrix Class:

S = csc_matrix(A)
print("Sparse 'column' matrix: \n",S)
print("Memory utilised (bytes): ", sys.getsizeof(S))
print("Type of the object", type(S))

The output of print statements:

Sparse 'column' matrix:
(0, 0) 1
(1, 2) 2
(2, 3) 2
(1, 5) 1
Memory utilised (bytes): 56
Type of the object: <class 'scipy.sparse.csc.csc_matrix'>

As it can be seen the size of the compressed matrices is 56 bytes and the original matrix size is 184 bytes.

For a more detailed explanation and code examples please refer to this article: https://limitlessdatascience.wordpress.com/2020/11/26/sparse-matrix-in-machine-learning/

C++ Boost: undefined reference to boost::system::generic_category()

After testing the proposed solutions described above, I found only these few of lines would work.

I am using Ubuntu 16.04.

cmake_minimum_required(VERSION 3.13)
project(myProject)

set(CMAKE_CXX_STANDARD 11)
add_executable(myProject main.cpp)

find_package(Boost 1.58.0 REQUIRED COMPONENTS system filesystem)
target_link_libraries(myProject ${Boost_LIBRARIES})

Printing out a number in assembly language?

Assembly language has no direct means of printing anything. Your assembler may or may not come with a library that supplies such a facility, otherwise you have to write it yourself, and it will be quite a complex function. You also have to decide where to print things - in a window, on the printer? In assembler, none of this is done for you.

JS search in object values

search(searchText) {
  let arrayOfMatchedObjects = arrayOfAllObjects.filter(object => {
    return JSON.stringify(object)
      .toString()
      .toLowerCase()
      .includes(searchText);
  });
  return arrayOfMatchedObjects;
}

This could be very simple, easy, fast and understandable Search function for some of you just like me.

Android: How can I get the current foreground activity (from a service)?

Just recently found out about this. With apis as:

  • minSdkVersion 19
  • targetSdkVersion 26

    ActivityManager.getCurrentActivity(context)

Hope this is of any use.

Compare string with all values in list

In Python you may use the in operator. You can do stuff like this:

>>> "c" in "abc"
True

Taking this further, you can check for complex structures, like tuples:

>>> (2, 4, 8) in ((1, 2, 3), (2, 4, 8))
True

Laravel assets url

You have to put all your assets in app/public folder, and to access them from your views you can use asset() helper method.

Ex. you can retrieve assets/images/image.png in your view as following:

<img src="{{asset('assets/images/image.png')}}">

Django. Override save for model

I have found one another simple way to store the data into the database

models.py

class LinkModel(models.Model):
    link = models.CharField(max_length=500)
    shortLink = models.CharField(max_length=30,unique=True)

In database I have only 2 variables

views.py

class HomeView(TemplateView):
    def post(self,request, *args, **kwargs):
        form = LinkForm(request.POST)

        if form.is_valid():
            text = form.cleaned_data['link'] # text for link

        dbobj = LinkModel()
        dbobj.link = text
        self.no = self.gen.generateShortLink() # no for shortLink
        dbobj.shortLink = str(self.no)
        dbobj.save()         # Saving from views.py

In this I have created the instance of model in views.py only and putting/saving data into 2 variables from views only.

What is the proper way to display the full InnerException?

If you're using Entity Framework, exception.ToString() will not gives you the details of DbEntityValidationException exceptions. You might want to use the same method to handle all your exception, like:

catch (Exception ex)
{
   Log.Error(GetExceptionDetails(ex));
}

Where GetExceptionDetails contains something like this:

public static string GetExceptionDetails(Exception ex)
{
    var stringBuilder = new StringBuilder();

    while (ex != null)
    {
        switch (ex)
        {
            case DbEntityValidationException dbEx:
                var errorMessages = dbEx.EntityValidationErrors.SelectMany(x => x.ValidationErrors).Select(x => x.ErrorMessage);
                var fullErrorMessage = string.Join("; ", errorMessages);
                var message = string.Concat(ex.Message, " The validation errors are: ", fullErrorMessage);

                stringBuilder.Insert(0, dbEx.StackTrace);
                stringBuilder.Insert(0, message);
                break;

            default:
                stringBuilder.Insert(0, ex.StackTrace);
                stringBuilder.Insert(0, ex.Message);
                break;
        }

        ex = ex.InnerException;
    }

    return stringBuilder.ToString();
}

difference between $query>num_rows() and $this->db->count_all_results() in CodeIgniter & which one is recommended

Simply as bellow;

$this->db->get('table_name')->num_rows();

This will get number of rows/records. however you can use search parameters as well;

$this->db->select('col1','col2')->where('col'=>'crieterion')->get('table_name')->num_rows();

However, it should be noted that you will see bad bad errors if applying as below;

$this->db->get('table_name')->result()->num_rows();

Detect all Firefox versions in JS

here it it

var ffversion = '18';
var is_firefox = navigator.userAgent.toLowerCase().indexOf('firefox/'+ffversion) > -1;
alert(is_firefox);

Error You must specify a region when running command aws ecs list-container-instances

#1- Run this to configure the region once and for all:

aws configure set region us-east-1 --profile admin
  • Change admin next to the profile if it's different.

  • Change us-east-1 if your region is different.

#2- Run your command again:

aws ecs list-container-instances --cluster default

How do I use the conditional operator (? :) in Ruby?

Your use of ERB suggests that you are in Rails. If so, then consider truncate, a built-in helper which will do the job for you:

<% question = truncate(question, :length=>30) %>

How do I ignore ampersands in a SQL script running from SQL Plus?

I had a CASE statement with WHEN column = 'sometext & more text' THEN ....

I replaced it with WHEN column = 'sometext ' || CHR(38) || ' more text' THEN ...

you could also use WHEN column LIKE 'sometext _ more text' THEN ...

(_ is the wildcard for a single character)

Upload folder with subfolders using S3 and the AWS console

It's worth mentioning that if you are simply using S3 for backups, you should just zip the folder and then upload that. This Will save you upload time and costs.

If you are not sure how to do efficient zipping from the terminal have a look here for OSX.

And $ zip -r archive_name.zip folder_to_compress for Windows. Alternatively a client such as 7-Zip would be sufficient for Windows users

Android - Center TextView Horizontally in LinearLayout

What's happening is that since the the TextView is filling the whole width of the inner LinearLayout it is already in the horizontal center of the layout. When you use android:layout_gravity it places the widget, as a whole, in the gravity specified. Instead of placing the whole widget center what you're really trying to do is place the content in the center which can be accomplished with android:gravity="center_horizontal" and the android:layout_gravity attribute can be removed.

convert string to specific datetime format?

This another helpful code:

"2011-05-19 10:30:14".to_datetime.strftime('%a %b %d %H:%M:%S %Z %Y')

"Uncaught Error: [$injector:unpr]" with angular after deployment

If you follow your link, it tells you that the error results from the $injector not being able to resolve your dependencies. This is a common issue with angular when the javascript gets minified/uglified/whatever you're doing to it for production.

The issue is when you have e.g. a controller;

angular.module("MyApp").controller("MyCtrl", function($scope, $q) {
  // your code
})

The minification changes $scope and $q into random variables that doesn't tell angular what to inject. The solution is to declare your dependencies like this:

angular.module("MyApp")
  .controller("MyCtrl", ["$scope", "$q", function($scope, $q) {
  // your code
}])

That should fix your problem.

Just to re-iterate, everything I've said is at the link the error message provides to you.

Define: What is a HashSet?

Simply said and without revealing the kitchen secrets: a set in general, is a collection that contains no duplicate elements, and whose elements are in no particular order. So, A HashSet<T> is similar to a generic List<T>, but is optimized for fast lookups (via hashtables, as the name implies) at the cost of losing order.

SQL NVARCHAR and VARCHAR Limits

The accepted answer helped me but I got tripped up while doing concatenation of varchars involving case statements. I know the OP's question does not involve case statements but I thought this would be helpful to post here for others like me who ended up here while struggling to build long dynamic SQL statements involving case statements.

When using case statements with string concatenation the rules mentioned in the accepted answer apply to each section of the case statement independently.

declare @l_sql varchar(max) = ''

set @l_sql = @l_sql +
case when 1=1 then
    --without this correction the result is truncated
    --CONVERT(VARCHAR(MAX), '')
 +REPLICATE('1', 8000)
 +REPLICATE('1', 8000)
end

print len(@l_sql)

import module from string variable

The __import__ function can be a bit hard to understand.

If you change

i = __import__('matplotlib.text')

to

i = __import__('matplotlib.text', fromlist=[''])

then i will refer to matplotlib.text.

In Python 2.7 and Python 3.1 or later, you can use importlib:

import importlib

i = importlib.import_module("matplotlib.text")

Some notes

  • If you're trying to import something from a sub-folder e.g. ./feature/email.py, the code will look like importlib.import_module("feature.email")

  • You can't import anything if there is no __init__.py in the folder with file you are trying to import

SQL: Alias Column Name for Use in CASE Statement

In MySql, alice name may not work, therefore put the original column name in the CASE statement

 SELECT col1 as a, CASE WHEN col1 = 'test' THEN 'yes' END as value FROM table;

Sometimes above query also may return error, I don`t know why (I faced this problem in my two different development machine). Therefore put the CASE statement into the "(...)" as below:

SELECT col1 as a, (CASE WHEN col1 = 'test' THEN 'yes' END) as value FROM table;

Check if url contains string with JQuery

if(window.location.href.indexOf("?added-to-cart=555") >= 0)

It's window.location.href, not window.location.

How to implement a binary search tree in Python?

The problem, or at least one problem with your code is here:-

def insert(self,node,someNumber):
    if node is None:
        node = Node(someNumber)
    else:
        if node.data > someNumber:
            self.insert(node.rchild,someNumber)
        else:
            self.insert(node.rchild, someNumber)
    return

You see the statement "if node.data > someNumber:" and the associated "else:" statement both have the same code after them. i.e you do the same thing whether the if statement is true or false.

I'd suggest you probably intended to do different things here, perhaps one of these should say self.insert(node.lchild, someNumber) ?

Disable Logback in SpringBoot

Using Gradle & Lombok, here is the simplest configuration for Log4j2 that worked for me using the latest Spring Boot (2.4.1 at this time) :

build.gradle (partial)

configurations {
    compileOnly { extendsFrom annotationProcessor }
    compile.exclude module: 'spring-boot-starter-logging'
}


dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-web'
    implementation 'org.springframework.boot:spring-boot-starter-security' 
    implementation 'org.springframework.boot:spring-boot-starter-web-services'
    implementation 'org.springframework.boot:spring-boot-starter-log4j2'

    compileOnly 'org.projectlombok:lombok'

    // (*** other dependencies ***)

    annotationProcessor 'org.projectlombok:lombok'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
    testImplementation 'org.springframework.security:spring-security-test'
}

I noticed you will get errors if you include spring-bbot-starter-log4j2 as a compileOnly dependency instead of as an implementation.

Just annotate your classes with @Log4j2 (or @Slf4j) and lombok will make available a log variable you can use for logging.

As usual, provide a log4j2.xml configuration file in your /src/main/resources folder.

Setting environment variables in Linux using Bash

I think you're looking for export - though I could be wrong.. I've never played with tcsh before. Use the following syntax:

export VARIABLE=value

js 'types' can only be used in a .ts file - Visual Studio Code using @ts-check

Use "javascript.validate.enable": false in your VS Code settings, It doesn't disable ESLINT. I use both ESLINT & Flow. Simply follow the instructions Flow For Vs Code Setup

Adding this line in settings.json. Helps "javascript.validate.enable": false

Wait for shell command to complete

what you proposed with a change at the parenthesis at the Run command worked fine with VBA for me

Dim wsh As Object
Set wsh = VBA.CreateObject("WScript.Shell")
Dim waitOnReturn As Boolean: waitOnReturn = True
Dim windowStyle As Integer: windowStyle = 1
Dim errorCode As Integer
wsh.Run "C:\folder\runbat.bat", windowStyle, waitOnReturn

How to select top n rows from a datatable/dataview in ASP.NET

I just used Midhat's answer but appended CopyToDataTable() on the end.

The code below is an extension to the answer that I used to quickly enable some paging.

int pageNum = 1;
int pageSize = 25;

DataTable dtPage = dt.Rows.Cast<System.Data.DataRow>().Skip((pageNum - 1) * pageSize).Take(pageSize).CopyToDataTable();

How to convert a Binary String to a base 10 integer in Java

int foo = Integer.parseInt("1001", 2);

works just fine if you are dealing with positive numbers but if you need to deal with signed numbers you may need to sign extend your string then convert to an Int

public class bit_fun {
    public static void main(String[] args) {
        int x= (int)Long.parseLong("FFFFFFFF", 16);
        System.out.println("x =" +x);       

        System.out.println(signExtend("1"));
        x= (int)Long.parseLong(signExtend("1"), 2);
        System.out.println("x =" +x);

        System.out.println(signExtend("0"));
        x= (int)Long.parseLong(signExtend("0"), 2);
        System.out.println("x =" +x);

        System.out.println(signExtend("1000"));
        x= (int)Long.parseLong(signExtend("1000"), 2);
        System.out.println("x =" +x);

        System.out.println(signExtend("01000"));
        x= (int)Long.parseLong(signExtend("01000"), 2);
        System.out.println("x =" +x);
    }

    private static String signExtend(String str){
        //TODO add bounds checking
        int n=32-str.length();
        char[] sign_ext = new char[n];
        Arrays.fill(sign_ext, str.charAt(0));

        return new String(sign_ext)+str;
    }
}

output:
x =-1
11111111111111111111111111111111
x =-1
00000000000000000000000000000000
x =0
11111111111111111111111111111000
x =-8
00000000000000000000000000001000
x =8 

I hope that helps!

How to specify in crontab by what user to run script?

Since you're running Ubuntu, your system crontab is located at /etc/crontab.

As the root user (or using sudo), you can simply edit this file and specify the user that should run this command. Here is the format of entries in the system crontab and how you should enter your command:

# m h dom mon dow user  command
*/1 * * * * www-data php5 /var/www/web/includes/crontab/queue_process.php >> /var/www/web/includes/crontab/queue.log 2>&1

Of course the permissions for your php script and your log file should be set so that the www-data user has access to them.

Why I'm getting 'Non-static method should not be called statically' when invoking a method in a Eloquent model?

You can give like this

public static function getAll()
{

    return $posts = $this->all()->take(2)->get();

}

And when you call statically inside your controller function also..

Simple way to measure cell execution time in ipython notebook

This is not exactly beautiful but without extra software

class timeit():
    from datetime import datetime
    def __enter__(self):
        self.tic = self.datetime.now()
    def __exit__(self, *args, **kwargs):
        print('runtime: {}'.format(self.datetime.now() - self.tic))

Then you can run it like:

with timeit():
    # your code, e.g., 
    print(sum(range(int(1e7))))

% 49999995000000
% runtime: 0:00:00.338492

ValueError: unsupported pickle protocol: 3, python2 pickle can not load the file dumped by python 3 pickle?

Pickle uses different protocols to convert your data to a binary stream.

You must specify in python 3 a protocol lower than 3 in order to be able to load the data in python 2. You can specify the protocol parameter when invoking pickle.dump.

Why does jQuery or a DOM method such as getElementById not find the element?

As @FelixKling pointed out, the most likely scenario is that the nodes you are looking for do not exist (yet).

However, modern development practices can often manipulate document elements outside of the document tree either with DocumentFragments or simply detaching/reattaching current elements directly. Such techniques may be used as part of JavaScript templating or to avoid excessive repaint/reflow operations while the elements in question are being heavily altered.

Similarly, the new "Shadow DOM" functionality being rolled out across modern browsers allows elements to be part of the document, but not query-able by document.getElementById and all of its sibling methods (querySelector, etc.). This is done to encapsulate functionality and specifically hide it.

Again, though, it is most likely that the element you are looking for simply is not (yet) in the document, and you should do as Felix suggests. However, you should also be aware that that is increasingly not the only reason that an element might be unfindable (either temporarily or permanently).

Stop an input field in a form from being submitted

You can write an event handler for onsubmit that removes the name attribute from all of the input fields that you want not to be included in the form submission.

Here's a quick untested example:

var noSubmitElements = [ 'someFormElementID1', 'someFormElementID2' ]; //...
function submitForm() {
    for( var i = 0, j = noSubmitElements.length; i < j; i++ ) {
        document.getElementById(noSubmitElements[i]).removeAttribute('name');
    }
}
form.onsubmit = submitForm;

Is there a numpy builtin to reject outliers from a list

Here I find the outliers in x and substitute them with the median of a window of points (win) around them (taking from Benjamin Bannier answer the median deviation)

def outlier_smoother(x, m=3, win=3, plots=False):
    ''' finds outliers in x, points > m*mdev(x) [mdev:median deviation] 
    and replaces them with the median of win points around them '''
    x_corr = np.copy(x)
    d = np.abs(x - np.median(x))
    mdev = np.median(d)
    idxs_outliers = np.nonzero(d > m*mdev)[0]
    for i in idxs_outliers:
        if i-win < 0:
            x_corr[i] = np.median(np.append(x[0:i], x[i+1:i+win+1]))
        elif i+win+1 > len(x):
            x_corr[i] = np.median(np.append(x[i-win:i], x[i+1:len(x)]))
        else:
            x_corr[i] = np.median(np.append(x[i-win:i], x[i+1:i+win+1]))
    if plots:
        plt.figure('outlier_smoother', clear=True)
        plt.plot(x, label='orig.', lw=5)
        plt.plot(idxs_outliers, x[idxs_outliers], 'ro', label='outliers')                                                                                                                    
        plt.plot(x_corr, '-o', label='corrected')
        plt.legend()
    
    return x_corr

enter image description here

Where to find the complete definition of off_t type?

If you are having trouble tracing the definitions, you can use the preprocessed output of the compiler which will tell you all you need to know. E.g.

$ cat test.c
#include <stdio.h>
$ cc -E test.c | grep off_t
typedef long int __off_t;
typedef __off64_t __loff_t;
  __off_t __pos;
  __off_t _old_offset;
typedef __off_t off_t;
extern int fseeko (FILE *__stream, __off_t __off, int __whence);
extern __off_t ftello (FILE *__stream) ;

If you look at the complete output you can even see the exact header file location and line number where it was defined:

# 132 "/usr/include/bits/types.h" 2 3 4


typedef unsigned long int __dev_t;
typedef unsigned int __uid_t;
typedef unsigned int __gid_t;
typedef unsigned long int __ino_t;
typedef unsigned long int __ino64_t;
typedef unsigned int __mode_t;
typedef unsigned long int __nlink_t;
typedef long int __off_t;
typedef long int __off64_t;

...

# 91 "/usr/include/stdio.h" 3 4
typedef __off_t off_t;

Use of Java's Collections.singletonList()?

singletonList can hold instance of any object. Object state can be modify.

List<Character> list = new ArrayList<Character>();
list.add('X');
list.add('Y');
System.out.println("Initial list: "+ list);
List<List<Character>> list2 = Collections.singletonList(list);
list.add('Z');
System.out.println(list);
System.out.println(list2);

We can not define unmodifiableList like above.

Get value of input field inside an iframe

document.getElementById("idframe").contentWindow.document.getElementById("idelement").value;

How do you perform wireless debugging in Xcode 9 with iOS 11, Apple TV 4K, etc?

Network debugging requires Xcode 9.0 or later running on macOS 10.12.4 or later, and on the device, requires iOS 11.0 or later, or tvOS 11.0 or later.

iPhone

iOS 11 won't be available for 32bit devices, i.e. iPhone 5 and iPhone 5c and below. The first 64bit iPhone is 5s.

iPad

iPad mini 2 will be the oldest iPad with iOS 11 support.

iPod

iPod needs to be an iPod 6 to be able to run iOS.

If you use your devices not only for developing but also for production, be warned that a beta OS is not for the faint hearted ;-)

How to remove from a map while iterating it?

Pretty sad, eh? The way I usually do it is build up a container of iterators instead of deleting during traversal. Then loop through the container and use map.erase()

std::map<K,V> map;
std::list< std::map<K,V>::iterator > iteratorList;

for(auto i : map ){
    if ( needs_removing(i)){
        iteratorList.push_back(i);
    }
}
for(auto i : iteratorList){
    map.erase(*i)
}

Android: How to enable/disable option menu item on button click?

Anyway, the documentation covers all the things.

Changing menu items at runtime

Once the activity is created, the onCreateOptionsMenu() method is called only once, as described above. The system keeps and re-uses the Menu you define in this method until your activity is destroyed. If you want to change the Options Menu any time after it's first created, you must override the onPrepareOptionsMenu() method. This passes you the Menu object as it currently exists. This is useful if you'd like to remove, add, disable, or enable menu items depending on the current state of your application.

E.g.

@Override
public boolean onPrepareOptionsMenu (Menu menu) {
    if (isFinalized) {
        menu.getItem(1).setEnabled(false);
        // You can also use something like:
        // menu.findItem(R.id.example_foobar).setEnabled(false);
    }
    return true;
}

On Android 3.0 and higher, the options menu is considered to always be open when menu items are presented in the action bar. When an event occurs and you want to perform a menu update, you must call invalidateOptionsMenu() to request that the system call onPrepareOptionsMenu().

Using Notepad++ to validate XML against an XSD

  1. In Notepad++ go to Plugins > Plugin manager > Show Plugin Manager then find Xml Tools plugin. Tick the box and click Install

    enter image description here

  2. Open XML document you want to validate and click Ctrl+Shift+Alt+M (Or use Menu if this is your preference Plugins > XML Tools > Validate Now).
    Following dialog will open: enter image description here

  3. Click on .... Point to XSD file and I am pretty sure you'll be able to handle things from here.

Hope this saves you some time.

EDIT: Plugin manager was not included in some versions of Notepad++ because many users didn't like commercials that it used to show. If you want to keep an older version, however still want plugin manager, you can get it on github, and install it by extracting the archive and copying contents to plugins and updates folder.
In version 7.7.1 plugin manager is back under a different guise... Plugin Admin so now you can simply update notepad++ and have it back.

enter image description here

Rollback transaction after @Test

You need to run your test with a Spring context and a transaction manager, e.g.,

@RunWith(SpringJUnit4ClassRunner.class)  
@ContextConfiguration(locations = {"/your-applicationContext.xml"})
@TransactionConfiguration(transactionManager="txMgr")
public class StudentSystemTest {

     @Test
     public void testTransactionalService() {
         // test transactional service
     }

     @Test
     @Transactional
     public void testNonTransactionalService() {
         // test non-transactional service
     }
}

See chapter 3.5.8. Transaction Management of the Spring reference for further details.

Is there a no-duplicate List implementation out there?

I needed something like that, so I went to the commons collections and used the SetUniqueList, but when I ran some performance test, I found that it seems not optimized comparing to the case if I want to use a Set and obtain an Array using the Set.toArray() method.

The SetUniqueTest took 20:1 time to fill and then traverse 100,000 Strings comparing to the other implementation, which is a big deal difference.

So, if you worry about the performance, I recommend you to use the Set and Get an Array instead of using the SetUniqueList, unless you really need the logic of the SetUniqueList, then you'll need to check other solutions...

Testing code main method:

public static void main(String[] args) {


SetUniqueList pq = SetUniqueList.decorate(new ArrayList());
Set s = new TreeSet();

long t1 = 0L;
long t2 = 0L;
String t;


t1 = System.nanoTime();
for (int i = 0; i < 200000; i++) {
    pq.add("a" + Math.random());
}
while (!pq.isEmpty()) {
    t = (String) pq.remove(0);
}
t1 = System.nanoTime() - t1;

t2 = System.nanoTime();
for (int i = 0; i < 200000; i++) {
    s.add("a" + Math.random());
}

s.clear();
String[] d = (String[]) s.toArray(new String[0]);
s.clear();
for (int i = 0; i < d.length; i++) {
    t = d[i];

}
t2 = System.nanoTime() - t2;

System.out.println((double)t1/1000/1000/1000); //seconds
System.out.println((double)t2/1000/1000/1000); //seconds
System.out.println(((double) t1) / t2);        //comparing results

}

Regards, Mohammed Sleem

How do I add my bot to a channel?

Now all clients allow to do it, but it's not pretty simple.
In any Telegram client:

  1. Open Channel info (in app title)
  2. Choose Administrators
  3. Add Administrator
  4. There will be no bots in contact list, so you need to search for it. Enter your bot's username
  5. Clicking on it you make it as administrator.

enter image description here

jquery append div inside div with id and manipulate

It's just the wrong order

var e = $('<div style="display:block; float:left;width:'+width+'px; height:'+height+'px; margin-top:'+positionY+'px;margin-left:'+positionX+'px;border:1px dashed #CCCCCC;"></div>');
$('#box').append(e);    
e.attr('id', 'myid');

Append first and then access/set attr.

Make DateTimePicker work as TimePicker only in WinForms

The best way to do this is this:

datetimepicker.Format = DatetimePickerFormat.Custom;
datetimepicker.CustomFormat = "HH:mm tt";
datetimepicker.ShowUpDowm = true;

Fixed header, footer with scrollable content

Now we've got CSS grid. Welcome to 2019.

_x000D_
_x000D_
/* Required */_x000D_
body {_x000D_
   margin: 0;_x000D_
   height: 100%;_x000D_
}_x000D_
_x000D_
#wrapper {_x000D_
   height: 100vh;_x000D_
   display: grid;_x000D_
   grid-template-rows: 30px 1fr 30px;_x000D_
}_x000D_
_x000D_
#content {_x000D_
   overflow-y: scroll;_x000D_
}_x000D_
_x000D_
/* Optional */_x000D_
#wrapper > * {_x000D_
   padding: 5px;_x000D_
}_x000D_
_x000D_
#header {_x000D_
   background-color: #ff0000ff;_x000D_
}_x000D_
_x000D_
#content {_x000D_
   background-color: #00ff00ff;_x000D_
}_x000D_
_x000D_
#footer {_x000D_
   background-color: #0000ffff;_x000D_
}
_x000D_
<body>_x000D_
   <div id="wrapper">_x000D_
      <div id="header">Header Content</div>_x000D_
      <div id="content">_x000D_
         Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum._x000D_
      </div>_x000D_
      <div id="footer">Footer Content</div>_x000D_
   </div>_x000D_
</body>
_x000D_
_x000D_
_x000D_

Django DateField default options

You could also use lambda. Useful if you're using django.utils.timezone.now

date = models.DateField(_("Date"), default=lambda: now().date())

How to pass an ArrayList to a varargs method parameter?

Source article: Passing a list as an argument to a vararg method


Use the toArray(T[] arr) method.

.getMap(locations.toArray(new WorldLocation[locations.size()]))

(toArray(new WorldLocation[0]) also works, but you would allocate a zero-length array for no reason.)


Here's a complete example:

public static void method(String... strs) {
    for (String s : strs)
        System.out.println(s);
}

...
    List<String> strs = new ArrayList<String>();
    strs.add("hello");
    strs.add("world");
    
    method(strs.toArray(new String[strs.size()]));
    //     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...

PHP equivalent of .NET/Java's toString()

Double quotes should work too... it should create a string, then it should APPEND/INSERT the casted STRING value of $myVar in between 2 empty strings.

take(1) vs first()

Here are three Observables A, B, and C with marble diagrams to explore the difference between first, take, and single operators:

first vs take vs single operators comparison

* Legend:
--o-- value
----! error
----| completion

Play with it at https://thinkrx.io/rxjs/first-vs-take-vs-single/ .

Already having all the answers, I wanted to add a more visual explanation

Hope it helps someone

Fix Access denied for user 'root'@'localhost' for phpMyAdmin

What worked for me:

Go to config.inc.php.

Change

$cfg['Servers'][$i]['AllowNoPassword'] = true;

to

$cfg['Servers'][$i]['AllowNoPassword'] = false;

Change

$cfg['Servers'][$i]['password'] = '';

to

$cfg['Servers'][$i]['password'] = ' ';

Change

$cfg['Servers'][$i]['auth_type'] = 'config';

to

$cfg['Servers'][$i]['auth_type'] = 'http';

Reload the page http://localhost/phpmyadmin

Type : root
pass : (empty)

Now you have access to it. :)

JPA - Returning an auto generated id after persist()

The ID is only guaranteed to be generated at flush time. Persisting an entity only makes it "attached" to the persistence context. So, either flush the entity manager explicitely:

em.persist(abc);
em.flush();
return abc.getId();

or return the entity itself rather than its ID. When the transaction ends, the flush will happen, and users of the entity outside of the transaction will thus see the generated ID in the entity.

@Override
public ABC addNewABC(ABC abc) {
    abcDao.insertABC(abc);
    return abc;
}

Shortest way to print current year in a website

For React.js, the following is what worked for me in the footer...

render() {
    const yearNow = new Date().getFullYear();
    return (
    <div className="copyright">&copy; Company 2015-{yearNow}</div>
);
}