Programs & Examples On #Named

How to enable named/bind/DNS full logging?

I usually expand each log out into it's own channel and then to a separate log file, certainly makes things easier when you are trying to debug specific issues. So my logging section looks like the following:

logging {
    channel default_file {
        file "/var/log/named/default.log" versions 3 size 5m;
        severity dynamic;
        print-time yes;
    };
    channel general_file {
        file "/var/log/named/general.log" versions 3 size 5m;
        severity dynamic;
        print-time yes;
    };
    channel database_file {
        file "/var/log/named/database.log" versions 3 size 5m;
        severity dynamic;
        print-time yes;
    };
    channel security_file {
        file "/var/log/named/security.log" versions 3 size 5m;
        severity dynamic;
        print-time yes;
    };
    channel config_file {
        file "/var/log/named/config.log" versions 3 size 5m;
        severity dynamic;
        print-time yes;
    };
    channel resolver_file {
        file "/var/log/named/resolver.log" versions 3 size 5m;
        severity dynamic;
        print-time yes;
    };
    channel xfer-in_file {
        file "/var/log/named/xfer-in.log" versions 3 size 5m;
        severity dynamic;
        print-time yes;
    };
    channel xfer-out_file {
        file "/var/log/named/xfer-out.log" versions 3 size 5m;
        severity dynamic;
        print-time yes;
    };
    channel notify_file {
        file "/var/log/named/notify.log" versions 3 size 5m;
        severity dynamic;
        print-time yes;
    };
    channel client_file {
        file "/var/log/named/client.log" versions 3 size 5m;
        severity dynamic;
        print-time yes;
    };
    channel unmatched_file {
        file "/var/log/named/unmatched.log" versions 3 size 5m;
        severity dynamic;
        print-time yes;
    };
    channel queries_file {
        file "/var/log/named/queries.log" versions 3 size 5m;
        severity dynamic;
        print-time yes;
    };
    channel network_file {
        file "/var/log/named/network.log" versions 3 size 5m;
        severity dynamic;
        print-time yes;
    };
    channel update_file {
        file "/var/log/named/update.log" versions 3 size 5m;
        severity dynamic;
        print-time yes;
    };
    channel dispatch_file {
        file "/var/log/named/dispatch.log" versions 3 size 5m;
        severity dynamic;
        print-time yes;
    };
    channel dnssec_file {
        file "/var/log/named/dnssec.log" versions 3 size 5m;
        severity dynamic;
        print-time yes;
    };
    channel lame-servers_file {
        file "/var/log/named/lame-servers.log" versions 3 size 5m;
        severity dynamic;
        print-time yes;
    };

    category default { default_file; };
    category general { general_file; };
    category database { database_file; };
    category security { security_file; };
    category config { config_file; };
    category resolver { resolver_file; };
    category xfer-in { xfer-in_file; };
    category xfer-out { xfer-out_file; };
    category notify { notify_file; };
    category client { client_file; };
    category unmatched { unmatched_file; };
    category queries { queries_file; };
    category network { network_file; };
    category update { update_file; };
    category dispatch { dispatch_file; };
    category dnssec { dnssec_file; };
    category lame-servers { lame-servers_file; };
};

Hope this helps.

Purpose of #!/usr/bin/python3 shebang

This line helps find the program executable that will run the script. This shebang notation is fairly standard across most scripting languages (at least as used on grown-up operating systems).

An important aspect of this line is specifying which interpreter will be used. On many development-centered Linux distributions, for example, it is normal to have several versions of python installed at the same time.

Python 2.x and Python 3 are not 100% compatible, so this difference can be very important. So #! /usr/bin/python and #! /usr/bin/python3 are not the same (and neither are quite the same as #! /usr/bin/env python3 as noted elsewhere on this page.

How to reenable event.preventDefault?

You would have to unbind the event and either rebind to a separate event that does not preventDefault or just call the default event yourself later in the method after unbinding. There is no magical event.cancelled=false;

As requested

 $('form').submit( function(ev){

         ev.preventDefault();

         //later you decide you want to submit
         $(this).unbind('submit').submit()

  });

google console error `OR-IEH-01`

i found that my google payment account was not activated. i activated it and the error was solved. link for vitrification: google account verification

Tar error: Unexpected EOF in archive

I had a similar error, but in my case the cause was file renaming. I was creating a gzipped file file1.tar.gz and repeatedly updating it in another tarfile with tar -uvf ./combined.tar ./file1.tar.gz. I got the unexpected EOF error when after untarring combined.tar and trying to untar file1.tar.gz.

I noticed there was a difference in the output of file before and after tarring:

$file file1.tar.gz
file1.tar.gz: gzip compressed data, was "file1.tar", last modified: Mon Jul 29 12:00:00 2019, from Unix
$tar xvf combined.tar
$file file1.tar.gz
file1.tar.gz: gzip compressed data, was "file_old.tar", last modified: Mon Jul 29 12:00:00 2019, from Unix

So, it appears that the file had a different name when I originally created combined.tar, and using the tar update function doesn't overwrite the metadata for the gzipped filename. The solution was to recreate combined.tar from scratch instead of updating it.

I still don't know exactly what happened, since changing the name of a gzipped file doesn't normally break it.

horizontal scrollbar on top and bottom of table

As far as I'm aware this isn't possible with HTML and CSS.

How can I run MongoDB as a Windows service?

This was the only thing that worked for me. As everything had to be an absolute path:

C:\Program Files\MongoDB\Server\3.2\bin>mongod --install --dbpath=c:/data/db --logpath=c:/data/logs/log.txt

I also had to run it from admin cmd

Checking that a List is not empty in Hamcrest

This works:

assertThat(list,IsEmptyCollection.empty())

A connection was successfully established with the server, but then an error occurred during the login process. (Error Number: 233)

I got that error message in code line containing SqlConnection.Open() running my .NET code as x64 application. Running as x86 causing no errors.

Solution was to deactivate the Force protocol encryption option for TCP/IP in %windir%\System32\cliconfg.exe

Force protocol encryption

How to get process ID of background process?

pgrep can get you all of the child PIDs of a parent process. As mentioned earlier $$ is the current scripts PID. So, if you want a script that cleans up after itself, this should do the trick:

trap 'kill $( pgrep -P $$ | tr "\n" " " )' SIGINT SIGTERM EXIT

How to get SLF4J "Hello World" working with log4j?

you need to add 3 dependency ( API+ API implementation + log4j dependency) 
Add also this 
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.5</version>
</dependency>

# And to see log in command line , set log4j.properties 

# Root logger option
log4j.rootLogger=INFO, file, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.Target=System.out
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

#And to see log in file  , set log4j.properties 
# Direct log messages to a log file
log4j.appender.file=org.apache.log4j.RollingFileAppender
log4j.appender.file.File=./logs/logging.log
log4j.appender.file.MaxFileSize=10MB
log4j.appender.file.MaxBackupIndex=10
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-5p %c{1}:%L - %m%n

Squash the first two commits in Git?

There is an easier way to do this. Let's assume you're on the master branch

Create a new orphaned branch which will remove all commit history:

$ git checkout --orphan new_branch

Add your initial commit message:

$ git commit -a

Get rid of the old unmerged master branch:

$ git branch -D master

Rename your current branch new_branch to master:

$ git branch -m master

Force GUI update from UI Thread

Call Application.DoEvents() after setting the label, but you should do all the work in a separate thread instead, so the user may close the window.

How to set a cron job to run every 3 hours

Change Minute parameter to 0.

You can set the cron for every three hours as:

0 */3 * * * your command here ..

The remote server returned an error: (407) Proxy Authentication Required

Thought of writing this answer as nothing worked from above & you don't want to specify proxy location.

If you're using httpClient then consider this.

HttpClientHandler handler = new HttpClientHandler();

IWebProxy proxy = WebRequest.GetSystemWebProxy();
proxy.Credentials = CredentialCache.DefaultCredentials;
handler.Proxy = proxy;

var client = new HttpClient(handler);
// your next steps...

And if you're using HttpWebRequest:

HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri + _endpoint);

IWebProxy proxy = WebRequest.GetSystemWebProxy();
proxy.Credentials = CredentialCache.DefaultCredentials;
request.Proxy = proxy;

Kind referencce: https://medium.com/@siriphonnot/the-remote-server-returned-an-error-407-proxy-authentication-required-86ae489e401b

Get the item doubleclick event of listview

Either use the MouseDoubleClick event, and also, all the MouseClick events have a click count in the eventargs variable 'e'. So if e.ClickCount == 2, then doubleclicked.

Get the first element of each tuple in a list in Python

Use a list comprehension:

res_list = [x[0] for x in rows]

Below is a demonstration:

>>> rows = [(1, 2), (3, 4), (5, 6)]
>>> [x[0] for x in rows]
[1, 3, 5]
>>>

Alternately, you could use unpacking instead of x[0]:

res_list = [x for x,_ in rows]

Below is a demonstration:

>>> lst = [(1, 2), (3, 4), (5, 6)]
>>> [x for x,_ in lst]
[1, 3, 5]
>>>

Both methods practically do the same thing, so you can choose whichever you like.

Generate your own Error code in swift 3

I know you have already satisfied with an answer but if you are interested to know the right approach, then this might be helpful for you. I would prefer not to mix http-response error code with the error code in the error object (confused? please continue reading a bit...).

The http response codes are standard error codes about a http response defining generic situations when response is received and varies from 1xx to 5xx ( e.g 200 OK, 408 Request timed out,504 Gateway timeout etc - http://www.restapitutorial.com/httpstatuscodes.html )

The error code in a NSError object provides very specific identification to the kind of error the object describes for a particular domain of application/product/software. For example your application may use 1000 for "Sorry, You can't update this record more than once in a day" or say 1001 for "You need manager role to access this resource"... which are specific to your domain/application logic.

For a very small application, sometimes these two concepts are merged. But they are completely different as you can see and very important & helpful to design and work with large software.

So, there can be two techniques to handle the code in better way:

1. The completion callback will perform all the checks

completionHandler(data, httpResponse, responseError) 

2. Your method decides success and error situation and then invokes corresponding callback

if nil == responseError { 
   successCallback(data)
} else {
   failureCallback(data, responseError) // failure can have data also for standard REST request/response APIs
}

Happy coding :)

Text file in VBA: Open/Find Replace/SaveAs/Close File

I have had the same problem and came acrosse this site.

the solution to just set another "filename" in the

... for output as ... command was very simple and useful.

in addition (beyond the Application.GetSaveAsFilename() Dialog)

it is very simple to set a** new filename** just using

the replace command, so you may change the filename/extension

eg. (as from the first post)

sFileName = "C:\filelocation"
iFileNum = FreeFile

Open sFileName For Input As iFileNum
content = (...edit the content) 

Close iFileNum

now just set:

newFilename = replace(sFilename, ".txt", ".csv") to change the extension

or

newFilename = replace(sFilename, ".", "_edit.") for a differrent filename

and then just as before

iFileNum = FreeFile
Open newFileName For Output As iFileNum

Print #iFileNum, content
Close iFileNum 

I surfed over an hour to find out how to rename a txt-file,

with many different solutions, but it could be sooo easy :)

Check if element at position [x] exists in the list

int? here = (list.ElementAtOrDefault(2) != 0 ? list[2]:(int?) null);

Drop data frame columns by name

Another solution if you don't want to use @hadley's above: If "COLUMN_NAME" is the name of the column you want to drop:

df[,-which(names(df) == "COLUMN_NAME")]

jQuery: Check if button is clicked

$('input[type="button"]').click(function (e) {
    if (e.target) {
        alert(e.target.id + ' clicked');
    }
});

you should tweak this a little (eg. use a name in stead of an id to alert), but this way you have more generic function.

Catch multiple exceptions in one line (except block)

From Python Documentation:

An except clause may name multiple exceptions as a parenthesized tuple, for example

except (IDontLikeYouException, YouAreBeingMeanException) as e:
    pass

Or, for Python 2 only:

except (IDontLikeYouException, YouAreBeingMeanException), e:
    pass

Separating the exception from the variable with a comma will still work in Python 2.6 and 2.7, but is now deprecated and does not work in Python 3; now you should be using as.

mysql SELECT IF statement with OR

Presumably this would work:

IF(compliment = 'set' OR compliment = 'Y' OR compliment = 1, 'Y', 'N') AS customer_compliment

bootstrap popover not showing on top of all elements

When you have some styles on a parent element that interfere with a popover, you’ll want to specify a custom container so that the popover’s HTML appears within that element instead.

For instance say the parent for a popover is body then you can use.

    <a href="#" data-toggle="tooltip" data-container="body"> Popover One </a>

Other case might be when popover is placed inside some other element and you want to show popover over that element, then you'll need to specify that element in data-container. ex: Suppose, we have popover inside a bootstrap modal with id as 'modal-two', then you'll need to set 'data-container' to 'modal-two'.

    <a href="#" data-toggle="tooltip" data-container="#modal-two"> Popover Two </a>

Excel formula to reference 'CELL TO THE LEFT'

Please select the entire sheet and HOME > Styles - Conditional Formatting, New Rule..., Use a formula to determine which cells to format and Format values where this formula is true::

=A1<>XFD1

Format..., select choice of formatting, OK, OK.

jquery - fastest way to remove all rows from a very large table

It's better to avoid any kind of loops, just remove all elements directly like this:

$("#mytable > tbody").html("");

How do I convert an enum to a list in C#?

Here for usefulness... some code for getting the values into a list, which converts the enum into readable form for the text

public class KeyValuePair
  {
    public string Key { get; set; }

    public string Name { get; set; }

    public int Value { get; set; }

    public static List<KeyValuePair> ListFrom<T>()
    {
      var array = (T[])(Enum.GetValues(typeof(T)).Cast<T>());
      return array
        .Select(a => new KeyValuePair
          {
            Key = a.ToString(),
            Name = a.ToString().SplitCapitalizedWords(),
            Value = Convert.ToInt32(a)
          })
          .OrderBy(kvp => kvp.Name)
         .ToList();
    }
  }

.. and the supporting System.String extension method:

/// <summary>
/// Split a string on each occurrence of a capital (assumed to be a word)
/// e.g. MyBigToe returns "My Big Toe"
/// </summary>
public static string SplitCapitalizedWords(this string source)
{
  if (String.IsNullOrEmpty(source)) return String.Empty;
  var newText = new StringBuilder(source.Length * 2);
  newText.Append(source[0]);
  for (int i = 1; i < source.Length; i++)
  {
    if (char.IsUpper(source[i]))
      newText.Append(' ');
    newText.Append(source[i]);
  }
  return newText.ToString();
}

Is it better to return null or empty collection?

Depends on the situation. If it is a special case, then return null. If the function just happens to return an empty collection, then obviously returning that is ok. However, returning an empty collection as a special case because of invalid parameters or other reasons is NOT a good idea, because it is masking a special case condition.

Actually, in this case I usually prefer to throw an exception to make sure it is REALLY not ignored :)

Saying that it makes the code more robust (by returning an empty collection) as they do not have to handle the null condition is bad, as it is simply masking a problem that should be handled by the calling code.

Center text in table cell

How about simply (Please note, come up with a better name for the class name this is simply an example):

.centerText{
   text-align: center;
}


<div>
   <table style="width:100%">
   <tbody>
   <tr>
      <td class="centerText">Cell 1</td>
      <td>Cell 2</td>
    </tr>
    <tr>
      <td class="centerText">Cell 3</td>
      <td>Cell 4</td>
    </tr>
    </tbody>
    </table>
</div>

Example here

You can place the css in a separate file, which is recommended. In my example, I created a file called styles.css and placed my css rules in it. Then include it in the html document in the <head> section as follows:

<head>
    <link href="styles.css" rel="stylesheet" type="text/css">
</head>

The alternative, not creating a seperate css file, not recommended at all... Create <style> block in your <head> in the html document. Then just place your rules there.

<head>
 <style type="text/css">
   .centerText{
       text-align: center;
    }
 </style>
</head>

Ruby on Rails: How do I add placeholder text to a f.text_field?

With rails >= 3.0, you can simply use the placeholder option.

f.text_field :attr, placeholder: "placeholder text"

How to get the hostname of the docker host from inside a docker container on that host without env vars

I'm adding this because it's not mentioned in any of the other answers. You can give a container a specific hostname at runtime with the -h directive.

docker run -h=my.docker.container.example.com ubuntu:latest

You can use backticks (or whatever equivalent your shell uses) to get the output of hosthame into the -h argument.

docker run -h=`hostname` ubuntu:latest

There is a caveat, the value of hostname will be taken from the host you run the command from, so if you want the hostname of a virtual machine that's running your docker container then using hostname as an argument may not be correct if you are using the host machine to execute docker commands on the virtual machine.

NullPointerException in eclipse in Eclipse itself at PartServiceImpl.internalFixContext

I faced the same error, but only with files cloned from git that were assigned to a proprietary plugin. I realized that even after cloning the files from git, I needed to create a new project or import a project in eclipse and this resolved the error.

how to download image from any web page in java

   // Do you want to download an image?
   // But are u denied access?
   // well here is the solution.

    public static void DownloadImage(String search, String path) {

    // This will get input data from the server
    InputStream inputStream = null;

    // This will read the data from the server;
    OutputStream outputStream = null;

    try {
        // This will open a socket from client to server
        URL url = new URL(search);

       // This user agent is for if the server wants real humans to visit
        String USER_AGENT = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36";

       // This socket type will allow to set user_agent
        URLConnection con = url.openConnection();

        // Setting the user agent
        con.setRequestProperty("User-Agent", USER_AGENT);

        // Requesting input data from server
        inputStream = con.getInputStream();

        // Open local file writer
        outputStream = new FileOutputStream(path);

        // Limiting byte written to file per loop
        byte[] buffer = new byte[2048];

        // Increments file size
        int length;

        // Looping until server finishes
        while ((length = inputStream.read(buffer)) != -1) {
            // Writing data
            outputStream.write(buffer, 0, length);
        }
    } catch (Exception ex) {
        Logger.getLogger(WebCrawler.class.getName()).log(Level.SEVERE, null, ex);
     }

     // closing used resources
     // The computer will not be able to use the image
     // This is a must

     outputStream.close();
     inputStream.close();
}

How to convert image into byte array and byte array to base64 String in android?

They have wrapped most stuff need to solve your problem, one of the tests looks like this:

String filename = CSSURLEmbedderTest.class.getResource("folder.png").getPath().replace("%20", " ");
String code = "background: url(folder.png);";

StringWriter writer = new StringWriter();
embedder = new CSSURLEmbedder(new StringReader(code), true);
embedder.embedImages(writer, filename.substring(0, filename.lastIndexOf("/")+1));

String result = writer.toString();
assertEquals("background: url(" + folderDataURI + ");", result);

How to change button color with tkinter

Another way to change color of a button if you want to do multiple operations along with color change. Using the Tk().after method and binding a change method allows you to change color and do other operations.

Label.destroy is another example of the after method.

    def export_win():
        //Some Operation
        orig_color = export_finding_graph.cget("background")
        export_finding_graph.configure(background = "green")

        tt = "Exported"
        label = Label(tab1_closed_observations, text=tt, font=("Helvetica", 12))
        label.grid(row=0,column=0,padx=10,pady=5,columnspan=3)

        def change(orig_color):
            export_finding_graph.configure(background = orig_color)

        tab1_closed_observations.after(1000, lambda: change(orig_color))
        tab1_closed_observations.after(500, label.destroy)


    export_finding_graph = Button(tab1_closed_observations, text='Export', command=export_win)
    export_finding_graph.grid(row=6,column=4,padx=70,pady=20,sticky='we',columnspan=3)

You can also revert to the original color.

Reading a date using DataReader

 (DateTime)MyReader["ColumnName"];

OR

Convert.ToDateTime(MyReader["ColumnName"]);

How to find the sum of an array of numbers

If you happen to be using Lodash you can use the sum function

array = [1, 2, 3, 4];
sum = _.sum(array); // sum == 10

how to replace an entire column on Pandas.DataFrame

For those that struggle with the "SettingWithCopy" warning, here's a workaround which may not be so efficient, but still gets the job done.

Suppose you with to overwrite column_1 and column_3, but retain column_2 and column_4

columns_to_overwrite = ["column_1", "column_3"]

First delete the columns that you intend to replace...

original_df.drop(labels=columns_to_overwrite, axis="columns", inplace=True)

... then re-insert the columns, but using the values that you intended to overwrite

original_df[columns_to_overwrite] = other_data_frame[columns_to_overwrite]

Key Shortcut for Eclipse Imports

Some useful shortcuts. You're looking for the 1st one...

  1. Ctrl + Shift + O : Organize imports
  2. Ctrl + Shift + T : Open Type
  3. Ctrl + Shift + F4 : Close all Opened Editors
  4. Ctrl + O : Open declarations
  5. Ctrl + E : Open Editor
  6. Ctrl + / : Line Comment
  7. Alt + Shift + R : Rename
  8. Alt + Shift + L : extract to Local Variable
  9. Alt + Shift + M : extract to Method
  10. F3 : Open Declaration

Source Here

how to specify new environment location for conda create

If you want to use the --prefix or -p arguments, but want to avoid having to use the environment's full path to activate it, you need to edit the .condarc config file before you create the environment.

The .condarc file is in the home directory; C:\Users\<user> on Windows. Edit the values under the envs_dirs key to include the custom path for your environment. Assuming the custom path is D:\envs, the file should end up looking something like this:

ssl_verify: true
channels:
  - defaults
envs_dirs:
  - C:\Users\<user>\Anaconda3\envs
  - D:\envs

Then, when you create a new environment on that path, its name will appear along with the path when you run conda env list, and you should be able to activate it using only the name, and not the full path.

Command line screenshot

In summary, if you edit .condarc to include D:\envs, and then run conda env create -p D:\envs\myenv python=x.x, then activate myenv (or source activate myenv on Linux) should work.

Hope that helps!

P.S. I stumbled upon this through trial and error. I think what happens is when you edit the envs_dirs key, conda updates ~\.conda\environments.txt to include the environments found in all the directories specified under the envs_dirs, so they can be accessed without using absolute paths.

In Unix, how do you remove everything in the current directory and below it?

make sure you are in the correct directory

rm -rf *

Delete column from SQLite table

Just in case if it could help someone like me.

Based on the Official website and the Accepted answer, I made a code using C# that uses System.Data.SQLite NuGet package.

This code also preserves the Primary key and Foreign key.

CODE in C#:

void RemoveColumnFromSqlite (string tableName, string columnToRemove) {
 try {
    var mSqliteDbConnection = new SQLiteConnection ("Data Source=db_folder\\MySqliteBasedApp.db;Version=3;Page Size=1024;");
    mSqliteDbConnection.Open ();             
    // Reads all columns definitions from table
    List<string> columnDefinition = new List<string> ();
    var mSql = $"SELECT type, sql FROM sqlite_master WHERE tbl_name='{tableName}'";
    var mSqliteCommand = new SQLiteCommand (mSql, mSqliteDbConnection);
    string sqlScript = "";
    using (mSqliteReader = mSqliteCommand.ExecuteReader ()) {
       while (mSqliteReader.Read ()) {
          sqlScript = mSqliteReader["sql"].ToString ();
          break;
       }
    }
    if (!string.IsNullOrEmpty (sqlScript)) {
       // Gets string within first '(' and last ')' characters
       int firstIndex = sqlScript.IndexOf ("(");
       int lastIndex = sqlScript.LastIndexOf (")");
       if (firstIndex >= 0 && lastIndex <= sqlScript.Length - 1) {
          sqlScript = sqlScript.Substring (firstIndex, lastIndex - firstIndex + 1);
       }
       string[] scriptParts = sqlScript.Split (new string[] { "," }, StringSplitOptions.RemoveEmptyEntries);
       foreach (string s in scriptParts) {
          if (!s.Contains (columnToRemove)) {
             columnDefinition.Add (s);
          }
       }
    }
    string columnDefinitionString = string.Join (",", columnDefinition);
    // Reads all columns from table
    List<string> columns = new List<string> ();
    mSql = $"PRAGMA table_info({tableName})";
    mSqliteCommand = new SQLiteCommand (mSql, mSqliteDbConnection);
    using (mSqliteReader = mSqliteCommand.ExecuteReader ()) {
       while (mSqliteReader.Read ()) columns.Add (mSqliteReader["name"].ToString ());
    }
    columns.Remove (columnToRemove);
    string columnString = string.Join (",", columns);
    mSql = "PRAGMA foreign_keys=OFF";
    mSqliteCommand = new SQLiteCommand (mSql, mSqliteDbConnection);
    int n = mSqliteCommand.ExecuteNonQuery ();
    // Removes a column from the table
    using (SQLiteTransaction tr = mSqliteDbConnection.BeginTransaction ()) {
       using (SQLiteCommand cmd = mSqliteDbConnection.CreateCommand ()) {
          cmd.Transaction = tr;
          string query = $"CREATE TEMPORARY TABLE {tableName}_backup {columnDefinitionString}";
          cmd.CommandText = query;
          cmd.ExecuteNonQuery ();
          cmd.CommandText = $"INSERT INTO {tableName}_backup SELECT {columnString} FROM {tableName}";
          cmd.ExecuteNonQuery ();
          cmd.CommandText = $"DROP TABLE {tableName}";
          cmd.ExecuteNonQuery ();
          cmd.CommandText = $"CREATE TABLE {tableName} {columnDefinitionString}";
          cmd.ExecuteNonQuery ();
          cmd.CommandText = $"INSERT INTO {tableName} SELECT {columnString} FROM {tableName}_backup;";
          cmd.ExecuteNonQuery ();
          cmd.CommandText = $"DROP TABLE {tableName}_backup";
          cmd.ExecuteNonQuery ();
       }
       tr.Commit ();
    }
    mSql = "PRAGMA foreign_keys=ON";
    mSqliteCommand = new SQLiteCommand (mSql, mSqliteDbConnection);
    n = mSqliteCommand.ExecuteNonQuery ();
 } catch (Exception ex) {
    HandleExceptions (ex);
 }
}

The data-toggle attributes in Twitter Bootstrap

For example, say you were creating a web application to list and display recipes. You might want your customers to be able to sort the list, display features of the recipes, and so on before they choose the recipe to open. In order to do this, you need to associate things like cooking time, primary ingredient, meal position, and so on right inside the list elements for the recipes.

<li><a href="recipe1.html">Borscht</a></li>
<li><a href="recipe2.html">Chocolate Mousse</a></li>
<li><a href="recipe3.html">Almond Radiccio Salad</a></li>
<li><a href="recipe4.html">Deviled Eggs</a></li>

In order to get that information into the page, you could do many different things. You could add comments to each LI element, you could add rel attributes to the list items, you could place all the recipes in separate folders based on time, meal, and ingredient (i.e. ). The solution that most developers took was to use class attributes to store information about the current element. This has several advantages:

  • You can store multiple classes on an element
  • The class names can be human readable
  • It’s easy to access classes with JavaScript (className)
  • The class is associated with the element it’s on

But there are some major drawbacks to this method:

  • You have to remember what the classes do. If you forget or a new developer takes over the project, the classes might be removed or changed without realizing that that affects how the application runs.
  • Classes are also used for styling with CSS, and you might duplicate CSS classes with data classes by mistake, ending up with strange styles on your live pages.
  • It’s more difficult to add on multiple data elements. If you have multiple data elements, you need to access them in some way with your JavaScript, either by the name of the class or the position in the class list. But it’s easy to mess up.

All the other methods I suggested had these problems as well as others. But since it was the only way to quickly and easily include data, that’s what we did. HTML5 Data Attributes to the Rescue

HTML5 added a new type of attribute to any element—the custom data element (data-*). These are custom (denoted by the *) attributes that you can add to your HTML elements to define any type of data you want. They consist of two parts:

Attribute Name This is the name of the attribute. It must be at least one lowercase character and have the prefix data-. For example: data-main-ingredient, data-cooking-time, data-meal. This is the name of your data.

Attribute Vaule Like any other HTML attribute, you include the data itself in quotes separated by an equal sign. This data can be any string that is valid on a web page. For example: data-main-ingredient="chocolate".

You can then apply these data attributes to any HTML element you want. For example, you could define the information in the example list above:

<li data-main-ingredient="beets" data-cooking-time="1 hour" data-meal="dinner"><a href="recipe1.html">Borscht</a></li>
<li data-main-ingredient="chocolate" data-cooking-time="30 minutes" data-meal="dessert"><a href="recipe2.html">Chocolate Mousse</a></li>
<li data-main-ingredient="radiccio" data-cooking-time="20 minutes" data-meal="dinner"><a href="recipe1.html">Almond Radiccio Salad</a></li>
<li data-main-ingredient="eggs" data-cooking-time="15 minutes" data-meal="appetizer"><a href="recipe1.html">Deviled Eggs</a></li>

Once you have that information in your HTML, you will be able to access it with JavaScript and manipulate the page based on that data.

Stop floating divs from wrapping

The only way I've managed to do this is by using overflow: visible; and width: 20000px; on the parent element. There is no way to do this with CSS level 1 that I'm aware of and I refused to think I'd have to go all gung-ho with CSS level 3. The example below has 18 menus that extend beyond my 1920x1200 resolution LCD, if your screen is larger just duplicate the first tier menu elements or just resize the browser. Alternatively and with slightly lower levels of browser compatibility you could use CSS3 media queries.

Here is a full copy/paste example demonstration...

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<title>XHTML5 Menu Demonstration</title>
<style type="text/css">
* {border: 0; box-sizing: content-box; color: #f0f; font-size: 10px; margin: 0; padding: 0; transition-property: background-color, background-image, border, box-shadow, color, float, opacity, text-align, text-shadow; transition-duration: 0.5s; white-space: nowrap;}
a:link {color: #79b; text-decoration: none;}
a:visited {color: #579;}
a:focus, a:hover {color: #fff; text-decoration: underline;}
body {background-color: #444; overflow-x: hidden;}
body > header {background-color: #000; height: 64px; left: 0; position: absolute; right: 0; z-index: 2;}
body > header > nav {height: 32px; margin-left: 16px;}
body > header > nav a {font-size: 24px;}
main {border-color: transparent; border-style: solid; border-width: 64px 0 0; bottom: 0px; left: 0; overflow-x: hidden !important; overflow-y: auto; position: absolute; right: 0; top: 0; z-index: 1;}
main > * > * {background-color: #000;}
main > section {float: left; margin-top: 16px; width: 100%;}
nav[id='menu'] {overflow: visible; width: 20000px;}
nav[id='menu'] > ul {height: 32px;}
nav[id='menu'] > ul > li {float: left; width: 140px;}
nav[id='menu'] > ul > li > ul {background-color: rgba(0, 0, 0, 0.8); display: none; margin-left: -50px; width: 240px;}
nav[id='menu'] a {display: block; height: 32px; line-height: 32px; text-align: center; white-space: nowrap;}
nav[id='menu'] > ul {float: left; list-style:none;}
nav[id='menu'] ul li:hover ul {display: block;}
p, p *, span, span * {color: #fff;}
p {font-size: 20px; margin: 0 14px 0 14px; padding-bottom: 14px; text-indent: 1.5em;}
.hidden {display: none;}
.width_100 {width: 100%;}
</style>
</head>

<body>

<main>
<section style="height: 2000px;"><p>Hover the first menu at the top-left.</p></section>
</main>

<header>
<nav id="location"><a href="">Example</a><span> - </span><a href="">Blog</a><span> - </span><a href="">Browser Market Share</a></nav>
<nav id="menu">
<ul>
<li><a href="" tabindex="2">Menu 1 - Hover</a>
<ul>
<li><a href="" tabindex="2">Menu 1 B</a></li>
<li><a href="" tabindex="2">Menu 1 B</a></li>
<li><a href="" tabindex="2">Menu 1 B</a></li>
<li><a href="" tabindex="2">Menu 1 B</a></li>
<li><a href="" tabindex="2">Menu 1 B</a></li>
<li><a href="" tabindex="2">Menu 1 B</a></li>
<li><a href="" tabindex="2">Menu 1 B</a></li>
<li><a href="" tabindex="2">Menu 1 B</a></li>
</ul>
</li>
<li><a href="" tabindex="2">Menu 2</a></li>
<li><a href="" tabindex="2">Menu 3</a></li>
<li><a href="" tabindex="2">Menu 4</a></li>
<li><a href="" tabindex="2">Menu 5</a></li>
<li><a href="" tabindex="2">Menu 6</a></li>
<li><a href="" tabindex="2">Menu 7</a></li>
<li><a href="" tabindex="2">Menu 8</a></li>
<li><a href="" tabindex="2">Menu 9</a></li>
<li><a href="" tabindex="2">Menu 10</a></li>
<li><a href="" tabindex="2">Menu 11</a></li>
<li><a href="" tabindex="2">Menu 12</a></li>
<li><a href="" tabindex="2">Menu 13</a></li>
<li><a href="" tabindex="2">Menu 14</a></li>
<li><a href="" tabindex="2">Menu 15</a></li>
<li><a href="" tabindex="2">Menu 16</a></li>
<li><a href="" tabindex="2">Menu 17</a></li>
<li><a href="" tabindex="2">Menu 18</a></li>
</ul>
</nav>
</header>

</body>
</html>

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

You can use something like this:

printf("%.2f", number);

If you need to use the string for something other than printing out, use the NumberFormat class:

NumberFormat formatter = new DecimalFormatter("#.##");
String s = formatter.format(3.14159265); // Creates a string containing "3.14"

Override devise registrations controller

Very simple methods Just go to the terminal and the type following

rails g devise:controllers users //This will create devise controllers in controllers/users folder

Next to use custom views

rails g devise:views users //This will create devise views in views/users folder

now in your route.rb file

devise_for :users, controllers: {
           :sessions => "users/sessions",
           :registrations => "users/registrations" }

You can add other controllers too. This will make devise to use controllers in users folder and views in users folder.

Now you can customize your views as your desire and add your logic to controllers in controllers/users folder. Enjoy !

Delete files older than 15 days using PowerShell

Basically, you iterate over files under the given path, subtract the CreationTime of each file found from the current time, and compare against the Days property of the result. The -WhatIf switch will tell you what will happen without actually deleting the files (which files will be deleted), remove the switch to actually delete the files:

$old = 15
$now = Get-Date

Get-ChildItem $path -Recurse |
Where-Object {-not $_.PSIsContainer -and $now.Subtract($_.CreationTime).Days -gt $old } |
Remove-Item -WhatIf

How to _really_ programmatically change primary and accent color in Android Lollipop?

This is what you CAN do:

write a file in drawable folder, lets name it background.xml

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android" >
    <solid android:color="?attr/colorPrimary"/>
</shape>

then set your Layout's (or what so ever the case is) android:background="@drawable/background"

on setting your theme this color would represent the same.

Regex matching in a Bash if statement

There are a couple of important things to know about bash's [[ ]] construction. The first:

Word splitting and pathname expansion are not performed on the words between the [[ and ]]; tilde expansion, parameter and variable expansion, arithmetic expansion, command substitution, process substitution, and quote removal are performed.

The second thing:

An additional binary operator, ‘=~’, is available,... the string to the right of the operator is considered an extended regular expression and matched accordingly... Any part of the pattern may be quoted to force it to be matched as a string.

Consequently, $v on either side of the =~ will be expanded to the value of that variable, but the result will not be word-split or pathname-expanded. In other words, it's perfectly safe to leave variable expansions unquoted on the left-hand side, but you need to know that variable expansions will happen on the right-hand side.

So if you write: [[ $x =~ [$0-9a-zA-Z] ]], the $0 inside the regex on the right will be expanded before the regex is interpreted, which will probably cause the regex to fail to compile (unless the expansion of $0 ends with a digit or punctuation symbol whose ascii value is less than a digit). If you quote the right-hand side like-so [[ $x =~ "[$0-9a-zA-Z]" ]], then the right-hand side will be treated as an ordinary string, not a regex (and $0 will still be expanded). What you really want in this case is [[ $x =~ [\$0-9a-zA-Z] ]]

Similarly, the expression between the [[ and ]] is split into words before the regex is interpreted. So spaces in the regex need to be escaped or quoted. If you wanted to match letters, digits or spaces you could use: [[ $x =~ [0-9a-zA-Z\ ] ]]. Other characters similarly need to be escaped, like #, which would start a comment if not quoted. Of course, you can put the pattern into a variable:

pat="[0-9a-zA-Z ]"
if [[ $x =~ $pat ]]; then ...

For regexes which contain lots of characters which would need to be escaped or quoted to pass through bash's lexer, many people prefer this style. But beware: In this case, you cannot quote the variable expansion:

# This doesn't work:
if [[ $x =~ "$pat" ]]; then ...

Finally, I think what you are trying to do is to verify that the variable only contains valid characters. The easiest way to do this check is to make sure that it does not contain an invalid character. In other words, an expression like this:

valid='0-9a-zA-Z $%&#' # add almost whatever else you want to allow to the list
if [[ ! $x =~ [^$valid] ]]; then ...

! negates the test, turning it into a "does not match" operator, and a [^...] regex character class means "any character other than ...".

The combination of parameter expansion and regex operators can make bash regular expression syntax "almost readable", but there are still some gotchas. (Aren't there always?) One is that you could not put ] into $valid, even if $valid were quoted, except at the very beginning. (That's a Posix regex rule: if you want to include ] in a character class, it needs to go at the beginning. - can go at the beginning or the end, so if you need both ] and -, you need to start with ] and end with -, leading to the regex "I know what I'm doing" emoticon: [][-])

Spring Boot Remove Whitelabel Error Page

I had a similar issue WhiteLabel Error message on my Angular SPA whenever I did a refresh.

The fix was to create a controller that implements ErrorController but instead of returning a String, I had to return a ModelAndView object that forwards to /

@CrossOrigin
@RestController
public class IndexController implements ErrorController {
    
    private static final String PATH = "/error";
    
    @RequestMapping(value = PATH)
    public ModelAndView saveLeadQuery() {           
        return new ModelAndView("forward:/");
    }

    @Override
    public String getErrorPath() {
        return PATH;
    }
}

Best way to check if a character array is empty

if (text[0] == '\0')
{
    /* Code... */
}

Use this if you're coding for micro-controllers with little space on flash and/or RAM. You will waste a lot more flash using strlen than checking the first byte.

The above example is the fastest and less computation is required.

Extract part of a regex match

Try:

title = re.search('<title>(.*)</title>', html, re.IGNORECASE).group(1)

Can Selenium interact with an existing browser session?

It appears that this feature is not officially supported by selenium. But, Tarun Lalwani has created working Java code to provide the feature. Refer - http://tarunlalwani.com/post/reusing-existing-browser-session-selenium-java/

Here is the working sample code, copied from the above link:

import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.remote.*;
import org.openqa.selenium.remote.http.W3CHttpCommandCodec;
import org.openqa.selenium.remote.http.W3CHttpResponseCodec;

import java.io.IOException;
import java.lang.reflect.Field;
import java.net.URL;
import java.util.Collections;

public class TestClass {
    public static RemoteWebDriver createDriverFromSession(final SessionId sessionId, URL command_executor){
        CommandExecutor executor = new HttpCommandExecutor(command_executor) {

            @Override
            public Response execute(Command command) throws IOException {
                Response response = null;
                if (command.getName() == "newSession") {
                    response = new Response();
                    response.setSessionId(sessionId.toString());
                    response.setStatus(0);
                    response.setValue(Collections.<String, String>emptyMap());

                    try {
                        Field commandCodec = null;
                        commandCodec = this.getClass().getSuperclass().getDeclaredField("commandCodec");
                        commandCodec.setAccessible(true);
                        commandCodec.set(this, new W3CHttpCommandCodec());

                        Field responseCodec = null;
                        responseCodec = this.getClass().getSuperclass().getDeclaredField("responseCodec");
                        responseCodec.setAccessible(true);
                        responseCodec.set(this, new W3CHttpResponseCodec());
                    } catch (NoSuchFieldException e) {
                        e.printStackTrace();
                    } catch (IllegalAccessException e) {
                        e.printStackTrace();
                    }

                } else {
                    response = super.execute(command);
                }
                return response;
            }
        };

        return new RemoteWebDriver(executor, new DesiredCapabilities());
    }

    public static void main(String [] args) {

        ChromeDriver driver = new ChromeDriver();
        HttpCommandExecutor executor = (HttpCommandExecutor) driver.getCommandExecutor();
        URL url = executor.getAddressOfRemoteServer();
        SessionId session_id = driver.getSessionId();


        RemoteWebDriver driver2 = createDriverFromSession(session_id, url);
        driver2.get("http://tarunlalwani.com");
    }
}

Your test needs to have a RemoteWebDriver created from an existing browser session. To create that Driver, you only need to know the "session info", i.e. address of the server (local in our case) where the browser is running and the browser session id. To get these details, we can create one browser session with selenium, open the desired page, and then finally run the actual test script.

I don't know if there is a way to get session info for a session which was not created by selenium.

Here is an example of session info:

Address of remote server : http://localhost:24266. The port number is different for each session. Session Id : 534c7b561aacdd6dc319f60fed27d9d6.

How do you echo a 4-digit Unicode character in Bash?

The printf builtin (just as the coreutils' printf) knows the \u escape sequence which accepts 4-digit Unicode characters:

   \uHHHH Unicode (ISO/IEC 10646) character with hex value HHHH (4 digits)

Test with Bash 4.2.37(1):

$ printf '\u2620\n'
?

What is the meaning of ToString("X2")?

It prints the byte in Hexadecimal format.

No format string: 13

'X2' format string: 0D

http://msdn.microsoft.com/en-us/library/aa311428(v=vs.71).aspx

PHP list of specific files in a directory

The $files array will get all files in the directory which the specified extension

$directory = 'pathto/directory';
$files = array();
$allowed_ext = array( "xml", "png", "jpg", "jpeg", "txt", "doc", "xls","csv"); 
// Check if the directory exists or not
if (file_exists($directory) && is_dir($directory)) {
    // Get the files in the directory
    $scan_contents = scandir($directory);
    // Filter out the current (.) and parent (..) directories 
    $files_array = array_diff($scan_contents, array('.', '..'));
    // Get each files of our directory with line break
    foreach ($files_array as $file) {
        //Get the file path
        $file_path = "$directory/$file";
        // Get the file extension
        $file_ext = strtolower(pathinfo($file_path, PATHINFO_EXTENSION));        
        if (in_array($file_ext, $allowed_ext) ) {
            $files[] = $file_path;
        }
    }
} 
echo '<pre>$files:-';
print_r($files);
echo '</pre>';

Unable to login to SQL Server + SQL Server Authentication + Error: 18456

The correct solution to the problem is to make sure SQL server authentication is turned on for your SQL Server.

dbms_lob.getlength() vs. length() to find blob size in oracle

length and dbms_lob.getlength return the number of characters when applied to a CLOB (Character LOB). When applied to a BLOB (Binary LOB), dbms_lob.getlength will return the number of bytes, which may differ from the number of characters in a multi-byte character set.

As the documentation doesn't specify what happens when you apply length on a BLOB, I would advise against using it in that case. If you want the number of bytes in a BLOB, use dbms_lob.getlength.

Eclipse error ... cannot be resolved to a type

For many new users don't forget to add an asterisk (*) after your import statements if you wanna use all the classes in a package....for example

import java.io.*;

public class Learning 
{
    public static void main(String[] args) 
    {
        BufferedInputStream sd = new BufferedInputStream(System.in);
            // no error
    }
}

================================================================

import java.io;

public class Learning 
{
    public static void main(String[] args) 
    {
        BufferedInputStream sd = new BufferedInputStream(System.in);
            // BufferedInputStream cannot be resolved to a type error
    }
}

Is it necessary to use # for creating temp tables in SQL server?

Yes. You need to prefix the table name with "#" (hash) to create temporary tables.

If you do NOT need the table later, go ahead & create it. Temporary Tables are very much like normal tables. However, it gets created in tempdb. Also, it is only accessible via the current session i.e. For EG: if another user tries to access the temp table created by you, he'll not be able to do so.

"##" (double-hash creates "Global" temp table that can be accessed by other sessions as well.

Refer the below link for the Basics of Temporary Tables: http://www.codeproject.com/Articles/42553/Quick-Overview-Temporary-Tables-in-SQL-Server-2005

If the content of your table is less than 5000 rows & does NOT contain data types such as nvarchar(MAX), varbinary(MAX), consider using Table Variables.

They are the fastest as they are just like any other variables which are stored in the RAM. They are stored in tempdb as well, not in RAM.

DECLARE @ItemBack1 TABLE
(
 column1 int,
 column2 int,
 someInt int,
 someVarChar nvarchar(50)
);

INSERT INTO @ItemBack1
SELECT column1, 
       column2, 
       someInt, 
       someVarChar 
  FROM table2
 WHERE table2.ID = 7;

More Info on Table Variables: http://odetocode.com/articles/365.aspx

How to find good looking font color if background color is known?

In a recent application that I made, I used the inverted colors. With the r,g and b values in hand, just calculate (in this example, the color range varies from 0 to 255) :

r = 127-(r-127) and so on.

How can I decrease the size of Ratingbar?

The below snippet worked for me to resize the ratingBar

<RatingBar
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/ratingBar"
    style="?android:attr/ratingBarStyleIndicator"
    android:scaleX=".5"
    android:rating="3.5"
    android:scaleY=".5"
    android:transformPivotX="0dp"
    android:transformPivotY="0dp"
    android:max="5"/>

enter image description here

Remove all child nodes from a parent?

You can use .empty(), like this:

$("#foo").empty();

From the docs:

Remove all child nodes of the set of matched elements from the DOM.

How can I find the first and last date in a month using PHP?

$month=01;
$year=2015;
$num = cal_days_in_month(CAL_GREGORIAN, $month, $year);
echo $num;

display 31 last day of date

Convert JS Object to form data

Try JSON.stringify function as below

var postData = JSON.stringify(item);
var formData = new FormData();
formData.append("postData",postData );

Python FileNotFound

try block should be around open. Not around prompt.

while True:
    prompt = input("\n Hello to Sudoku valitator,"
    "\n \n Please type in the path to your file and press 'Enter': ")
    try:
        sudoku = open(prompt, 'r').readlines()
    except FileNotFoundError:
        print("Wrong file or file path")
    else:
        break

How to iterate through property names of Javascript object?

In JavaScript 1.8.5, Object.getOwnPropertyNames returns an array of all properties found directly upon a given object.

Object.getOwnPropertyNames ( obj )

and another method Object.keys, which returns an array containing the names of all of the given object's own enumerable properties.

Object.keys( obj )

I used forEach to list values and keys in obj, same as for (var key in obj) ..

Object.keys(obj).forEach(function (key) {
      console.log( key , obj[key] );
});

This all are new features in ECMAScript , the mothods getOwnPropertyNames, keys won't supports old browser's.

What is the difference between bindParam and bindValue?

You don't have to struggle any longer, when there exists a way lilke this:

$stmt = $pdo->prepare("SELECT * FROM someTable WHERE col = :val");
$stmt->execute([":val" => $bind]); 

Why is the Android emulator so slow? How can we speed up the Android emulator?

I had intermittent slow emulator (SDK v8.0) load times, up to three minutes on Intel Core i7 920 2.67 GHz CPU running on Xubuntu 10.04 VirtualBox 3.2.12 guest with Eclipse (3.6.1) loaded. I changed the VirtualBox guest memory from 1024 MB to 2048 MB and from that point on, I never experienced the slowness again (load times consistent at 33 seconds, CPU load consistent at 20%). Both Eclipse and the emulator are memory hogs.

Constants in Kotlin -- what's a recommended way to create them?

Avoid using companion objects. Behind the hood, getter and setter instance methods are created for the fields to be accessible. Calling instance methods is technically more expensive than calling static methods.

public class DbConstants {
    companion object {
        val TABLE_USER_ATTRIBUTE_EMPID = "_id"
        val TABLE_USER_ATTRIBUTE_DATA = "data"
    }

Instead define the constants in object.

Recommended practice :

object DbConstants {
        const val TABLE_USER_ATTRIBUTE_EMPID = "_id"
        const val TABLE_USER_ATTRIBUTE_DATA = "data"
}

and access them globally like this: DbConstants.TABLE_USER_ATTRIBUTE_EMPID

All inclusive Charset to avoid "java.nio.charset.MalformedInputException: Input length = 1"?

Creating BufferedReader from Files.newBufferedReader

Files.newBufferedReader(Paths.get("a.txt"), StandardCharsets.UTF_8);

when running the application it may throw the following exception:

java.nio.charset.MalformedInputException: Input length = 1

But

new BufferedReader(new InputStreamReader(new FileInputStream("a.txt"),"utf-8"));

works well.

The different is that, the former uses CharsetDecoder default action.

The default action for malformed-input and unmappable-character errors is to report them.

while the latter uses the REPLACE action.

cs.newDecoder().onMalformedInput(CodingErrorAction.REPLACE).onUnmappableCharacter(CodingErrorAction.REPLACE)

Zabbix server is not running: the information displayed may not be current

Maybe is configuration issue

nano /etc/zabbix/zabbix_server.conf

DBHost=localhost

DBName=zabbix_db

DBUser=zabbix_user

DBPassword=XXXXXXX

works for me on Zabbix 3.0 Centos 7

Creating an iframe with given HTML dynamically

Do this

...
var el = document.getElementById('targetFrame');

var frame_win = getIframeWindow(el);

console.log(frame_win);
...

getIframeWindow is defined here

function getIframeWindow(iframe_object) {
  var doc;

  if (iframe_object.contentWindow) {
    return iframe_object.contentWindow;
  }

  if (iframe_object.window) {
    return iframe_object.window;
  } 

  if (!doc && iframe_object.contentDocument) {
    doc = iframe_object.contentDocument;
  } 

  if (!doc && iframe_object.document) {
    doc = iframe_object.document;
  }

  if (doc && doc.defaultView) {
   return doc.defaultView;
  }

  if (doc && doc.parentWindow) {
    return doc.parentWindow;
  }

  return undefined;
}

Where does Chrome store extensions?

For my Mac, extensions were here:

~/Library/Application Support/Google/Chrome/Default/Extensions/

if you go to chrome://extensions you'll find the "ID" of each extension. That is going to be a directory within Extensions directory. It is there you'll find all of the extension's files.

Rounded table corners CSS only

The best solution I've found for rounded corners and other CSS3 behavior for IE<9 can be found here: http://css3pie.com/

Download the plug-in, copy to a directory in your solution structure. Then in your stylesheet make sure to have the behavior tag so that it pulls in the plug-in.

Simple example from my project which gives me rounded corners, color gradient, and box shadow for my table:

.table-canvas 
{
    -webkit-border-radius: 8px;
    -moz-border-radius: 8px;
    overflow:hidden;
    border-radius: 10px;
    -pie-background: linear-gradient(#ece9d8, #E5ECD8);   
    box-shadow: #666 0px 2px 3px;
    behavior: url(Include/PIE.htc);
    overflow: hidden;
}

Don't worry if your Visual Studio CSS intellisense gives you the green underline for unknown properites, it still works when you run it. Some of the elements are not very clearly documented, but the examples are pretty good, especially on the front page.

Greater than and less than in one statement

This is one ugly way to do this. I would just use a local variable.

EDIT: If size() > 0 as well.

if (orderBean.getFiles().size() + Integer.MIN_VALUE-1 < Integer.MIN_VALUE + 5-1)

How do I execute code AFTER a form has loaded?

I had the same problem, and solved it as follows:

Actually I want to show Message and close it automatically after 2 second. For that I had to generate (dynamically) simple form and one label showing message, stop message for 1500 ms so user read it. And Close dynamically created form. Shown event occur After load event. So code is

Form MessageForm = new Form();
MessageForm.Shown += (s, e1) => { 
    Thread t = new Thread(() => Thread.Sleep(1500)); 
    t.Start(); 
    t.Join(); 
    MessageForm.Close(); 
};

Read an Excel file directly from a R script

As noted above in many of the other answers, there are many good packages that connect to the XLS/X file and get the data in a reasonable way. However, you should be warned that under no circumstances should you use the clipboard (or a .csv) file to retrieve data from Excel. To see why, enter =1/3 into a cell in excel. Now, reduce the number of decimal points visible to you to two. Then copy and paste the data into R. Now save the CSV. You'll notice in both cases Excel has helpfully only kept the data that was visible to you through the interface and you've lost all of the precision in your actual source data.

Resetting a setTimeout

$(function() {

    (function(){

        var pthis = this;
        this.mseg = 115000;
        this.href = 'file.php'

        this.setTimer = function() { 
            return (window.setTimeout( function() {window.location.href = this.href;}, this.mseg));
        };
        this.timer = pthis.setTimer();

        this.clear = function(ref) { clearTimeout(ref.timer); ref.setTimer(); };
        $(window.document).click( function(){pthis.clear.apply(pthis, [pthis])} );

    })();

});

Find a pair of elements from an array whose sum equals a given number

int [] arr = {1,2,3,4,5,6,7,8,9,0};

var z = (from a in arr from b in arr where 10 - a == b select new { a, b }).ToList;

spring data jpa @query and pageable

A similar question was asked on the Spring forums, where it was pointed out that to apply pagination, a second subquery must be derived. Because the subquery is referring to the same fields, you need to ensure that your query uses aliases for the entities/tables it refers to. This means that where you wrote:

select * from internal_uddi where urn like

You should instead have:

select * from internal_uddi iu where iu.urn like ...

Create dynamic URLs in Flask with url_for()

Templates:

Pass function name and argument.

<a href="{{ url_for('get_blog_post',id = blog.id)}}">{{blog.title}}</a>

View,function

@app.route('/blog/post/<string:id>',methods=['GET'])
def get_blog_post(id):
    return id

SQL Server convert string to datetime

For instance you can use

update tablename set datetimefield='19980223 14:23:05'
update tablename set datetimefield='02/23/1998 14:23:05'
update tablename set datetimefield='1998-12-23 14:23:05'
update tablename set datetimefield='23 February 1998 14:23:05'
update tablename set datetimefield='1998-02-23T14:23:05'

You need to be careful of day/month order since this will be language dependent when the year is not specified first. If you specify the year first then there is no problem; date order will always be year-month-day.

Highlight the difference between two strings in PHP

What you are looking for is a "diff algorithm". A quick google search led me to this solution. I did not test it, but maybe it will do what you need.

System.Threading.Timer in C# it seems to be not working. It runs very fast every 3 second

 var span = TimeSpan.FromMinutes(2);
 var t = Task.Factory.StartNew(async delegate / () =>
   {
        this.SomeAsync();
        await Task.Delay(span, source.Token);
  }, source.Token, TaskCreationOptions.LongRunning, TaskScheduler.Default);

source.Cancel(true/or not);

// or use ThreadPool(whit defaul options thread) like this
Task.Start(()=>{...}), source.Token)

if u like use some loop thread inside ...

public async void RunForestRun(CancellationToken token)
{
  var t = await Task.Factory.StartNew(async delegate
   {
       while (true)
       {
           await Task.Delay(TimeSpan.FromSeconds(1), token)
                 .ContinueWith(task => { Console.WriteLine("End delay"); });
           this.PrintConsole(1);
        }
    }, token) // drop thread options to default values;
}

// And somewhere there
source.Cancel();
//or
token.ThrowIfCancellationRequested(); // try/ catch block requred.

Executing a batch file in a remote machine through PsExec

Here's my current solution to run any code remotely on a given machine or list of machines asynchronously with logging, too!

@echo off
:: by Ralph Buchfelder, thanks to Mark Russinovich and Rob van der Woude for their work!
:: requires PsExec.exe to be in the same directory (download from http://technet.microsoft.com/de-de/sysinternals/bb897553.aspx)
:: troubleshoot remote commands with PsExec arguments -i or -s if neccessary (see http://forum.sysinternals.com/pstools_forum8.html)
:: will run *in parallel* on a list of remote pcs (if given); to run serially please remove 'START "" CMD.EXE /C' from the psexec call


:: help
if '%1' =='-h' (
 echo.
 echo %~n0
 echo.
 echo Runs a command on one or many remote machines. If no input parameters
 echo are given you will be asked for a target remote machine.
 echo.
 echo You will be prompted for remote credentials with elevated privileges.
 echo.
 echo UNC paths and local paths can be supplied.
 echo Commands will be executed on the remote side just the way you typed
 echo them, so be sure to mind extensions and the path variable!
 echo.
 echo Please note that PsExec.exe must be allowed on remote machines, i.e.
 echo not blocked by firewall or antivirus solutions.
 echo.
 echo Syntax: %~n0 [^<inputfile^>]
 echo.
 echo     inputfile      = a plain text file ^(one hostname or ip address per line^)
 echo.
 echo.
 echo Example:
 echo %~n0 mylist.txt
 exit /b 0
)


:checkAdmin
>nul 2>&1 "%SYSTEMROOT%\system32\cacls.exe" "%SYSTEMROOT%\system32\config\system"
if '%errorlevel%' neq '0' (
 echo Set UAC = CreateObject^("Shell.Application"^) > "%temp%\getadmin.vbs"
 echo UAC.ShellExecute "%~s0", "", "", "runas", 1 >> "%temp%\getadmin.vbs"
 "%temp%\getadmin.vbs"
 del "%temp%\getadmin.vbs"
 exit /B
)
set ADMINTESTDIR=%WINDIR%\System32\Test_%RANDOM%
mkdir "%ADMINTESTDIR%" 2>NUL
if errorlevel 1 (
 cls
 echo ERROR: This script requires elevated privileges!
 echo.
 echo Launch by Right-Click / Run as Administrator ...
 pause
 exit /b 1
) else (
 rd /s /q "%ADMINTESTDIR%"
 echo Running with elevated privileges...
)
echo.


:checkRequirements
if not exist "%~dp0PsExec.exe" (
 echo PsExec.exe from Sysinternals/Microsoft not found 
 echo in %~dp0
 echo.
 echo Download from http://technet.microsoft.com/de-de/sysinternals/bb897553.aspx
 echo.
 pause
 exit /B
)


:environment
setlocal
echo.
echo %~n0
echo _____________________________
echo.
echo Working directory:  %cd%\
echo Script directory:   %~dp0
echo.
SET /P REMOTE_USER=Domain\Administrator : 
SET "psCommand=powershell -Command "$pword = read-host 'Kennwort' -AsSecureString ; ^
    $BSTR=[System.Runtime.InteropServices.Marshal]::SecureStringToBSTR($pword); ^
        [System.Runtime.InteropServices.Marshal]::PtrToStringAuto($BSTR)""
for /f "usebackq delims=" %%p in (`%psCommand%`) do set REMOTE_PASS=%%p
if NOT DEFINED REMOTE_PASS SET /P REMOTE_PASS=Password             : 
echo.
if '%1' =='' goto menu
SET REMOTE_LIST=%1


:inputMultipleTargets
if not exist %REMOTE_LIST% (
 echo File %REMOTE_LIST% not found
 goto menu
)
type %REMOTE_LIST% >nul
if '%errorlevel%' neq '0' (
 echo Access denied %REMOTE_LIST%
 goto menu
)
set batchProcessing=true
echo Batch processing:   %REMOTE_LIST%   ...
ping -n 2 127.0.0.1 >nul
goto runOnce


:menu
if exist "%~dp0last.computer"  set /p LAST_COMPUTER=<"%~dp0last.computer"
if exist "%~dp0last.listing"   set /p LAST_LISTING=<"%~dp0last.listing"
if exist "%~dp0last.directory" set /p LAST_DIRECTORY=<"%~dp0last.directory"
if exist "%~dp0last.command"   set /p LAST_COMMAND=<"%~dp0last.command"
if exist "%~dp0last.timestamp" set /p LAST_TIMESTAMP=<"%~dp0last.timestamp"
echo.
echo.
echo                (1)  select target computer [default]
echo                (2)  select multiple computers
echo                     -----------------------------------
echo                     last target : %LAST_COMPUTER%
echo                     last listing: %LAST_LISTING%
echo                     last path   : %LAST_DIRECTORY%
echo                     last command: %LAST_COMMAND%
echo                     last run    : %LAST_TIMESTAMP%
echo                     -----------------------------------
echo                (0)  exit
echo.
echo ENTER your choice.
echo.
echo.
:mychoice
SET /P mychoice=(0, 1, ...): 
if NOT DEFINED mychoice  goto promptSingleTarget
if "%mychoice%"=="1"     goto promptSingleTarget
if "%mychoice%"=="2"     goto promptMultipleTargets
if "%mychoice%"=="0"     goto end
goto mychoice


:promptMultipleTargets
echo.
echo Please provide an input file
echo [one IP address or hostname per line]
SET /P REMOTE_LIST=Filename             : 
goto inputMultipleTargets


:promptSingleTarget
SET batchProcessing=
echo.
echo Please provide a hostname
SET /P REMOTE_COMPUTER=Target computer      : 
goto runOnce


:runOnce
cls
echo Note: Paths are mandatory for CMD-commands (e.g. dir,copy) to work!
echo       Paths are provided on the remote machine via PUSHD.
echo.
SET /P REMOTE_PATH=UNC-Path or folder : 
SET /P REMOTE_CMD=Command with params: 
SET REMOTE_TIMESTAMP=%DATE% %TIME:~0,8%
echo.
echo Remote command starting (%REMOTE_PATH%\%REMOTE_CMD%) on %REMOTE_TIMESTAMP%...
if not defined batchProcessing goto runOnceSingle


:runOnceMulti
REM do for each line; this circumvents PsExec's @file to have stdouts separately
SET REMOTE_LOG=%~dp0\log\%REMOTE_LIST%
if not exist %REMOTE_LOG% md %REMOTE_LOG%
for /F "tokens=*" %%A in (%REMOTE_LIST%) do (
 if "%REMOTE_PATH%" =="" START "" CMD.EXE /C ^(%~dp0PSEXEC -u %REMOTE_USER% -p %REMOTE_PASS% -h -accepteula \\%%A cmd /c "%REMOTE_CMD%" ^>"%REMOTE_LOG%\%%A.log" 2^>"%REMOTE_LOG%\%%A_debug.log" ^)
 if not "%REMOTE_PATH%" =="" START "" CMD.EXE /C ^(%~dp0PSEXEC -u %REMOTE_USER% -p %REMOTE_PASS% -h -accepteula \\%%A cmd /c "pushd %REMOTE_PATH% && %REMOTE_CMD% & popd" ^>"%REMOTE_LOG%\%%A.log" 2^>"%REMOTE_LOG%\%%A_debug.log" ^)
)
goto restart


:runOnceSingle
SET REMOTE_LOG=%~dp0\log
if not exist %REMOTE_LOG% md %REMOTE_LOG%
if "%REMOTE_PATH%" =="" %~dp0PSEXEC -u %REMOTE_USER% -p %REMOTE_PASS% -h -accepteula \\%REMOTE_COMPUTER% cmd /c "%REMOTE_CMD%" >"%REMOTE_LOG%\%REMOTE_COMPUTER%.log" 2>"%REMOTE_LOG%\%REMOTE_COMPUTER%_debug.log"
if not "%REMOTE_PATH%" =="" %~dp0PSEXEC -u %REMOTE_USER% -p %REMOTE_PASS% -h -accepteula \\%REMOTE_COMPUTER% cmd /c "pushd %REMOTE_PATH% && %REMOTE_CMD% & popd" >"%REMOTE_LOG%\%REMOTE_COMPUTER%.log" 2>"%REMOTE_LOG%\%REMOTE_COMPUTER%_debug.log"
goto restart


:restart
echo.
echo.
echo Batch completed. Finished with last errorlevel %errorlevel% .
echo All outputs have been saved to %~dp0log\%REMOTE_TIMESTAMP%\.
echo %REMOTE_PATH% >"%~dp0last.directory"
echo %REMOTE_CMD% >"%~dp0last.command"
echo %REMOTE_LIST% >"%~dp0last.listing"
echo %REMOTE_COMPUTER% >"%~dp0last.computer"
echo %REMOTE_TIMESTAMP% >"%~dp0last.timestamp"
SET REMOTE_PATH=
SET REMOTE_CMD=
SET REMOTE_LIST=
SET REMOTE_COMPUTER=
SET REMOTE_LOG=
SET REMOTE_TIMESTAMP=
ping -n 2 127.0.0.1 >nul
goto menu


:end
SET REMOTE_USER=
SET REMOTE_PASS=

What is difference between XML Schema and DTD?

DTD indicates the syntax of the XML element

XML Schemas are Microsoft's alternative to DTD for validating XML

Regex for parsing directory and filename

Try this:

^(.+)\/([^\/]+)$

EDIT: escaped the forward slash to prevent problems when copy/pasting the Regex

Finding whether a point lies inside a rectangle or not

I've borrowed from Eric Bainville's answer:

0 <= dot(AB,AM) <= dot(AB,AB) && 0 <= dot(BC,BM) <= dot(BC,BC)

Which in javascript looks like this:

function pointInRectangle(m, r) {
    var AB = vector(r.A, r.B);
    var AM = vector(r.A, m);
    var BC = vector(r.B, r.C);
    var BM = vector(r.B, m);
    var dotABAM = dot(AB, AM);
    var dotABAB = dot(AB, AB);
    var dotBCBM = dot(BC, BM);
    var dotBCBC = dot(BC, BC);
    return 0 <= dotABAM && dotABAM <= dotABAB && 0 <= dotBCBM && dotBCBM <= dotBCBC;
}

function vector(p1, p2) {
    return {
            x: (p2.x - p1.x),
            y: (p2.y - p1.y)
    };
}

function dot(u, v) {
    return u.x * v.x + u.y * v.y; 
}

eg:

var r = {
    A: {x: 50, y: 0},
    B: {x: 0, y: 20},
    C: {x: 10, y: 50},
    D: {x: 60, y: 30}
};

var m = {x: 40, y: 20};

then:

pointInRectangle(m, r); // returns true.

Here's a codepen to draw the output as a visual test :) http://codepen.io/mattburns/pen/jrrprN

enter image description here

How do I set up a simple delegate to communicate between two view controllers?

Following solution is very basic and simple approach to send data from VC2 to VC1 using delegate .

PS: This solution is made in Xcode 9.X and Swift 4

Declared a protocol and created a delegate var into ViewControllerB

    import UIKit

    //Declare the Protocol into your SecondVC
    protocol DataDelegate {
        func sendData(data : String)
    }

    class ViewControllerB : UIViewController {

    //Declare the delegate property in your SecondVC
        var delegate : DataDelegate?
        var data : String = "Send data to ViewControllerA."
        override func viewDidLoad() {
            super.viewDidLoad()
        }

        @IBAction func btnSendDataPushed(_ sender: UIButton) {
                // Call the delegate method from SecondVC
                self.delegate?.sendData(data:self.data)
                dismiss(animated: true, completion: nil)
            }
        }

ViewControllerA confirms the protocol and expected to receive data via delegate method sendData

    import UIKit
        // Conform the  DataDelegate protocol in ViewControllerA
        class ViewControllerA : UIViewController , DataDelegate {
        @IBOutlet weak var dataLabel: UILabel!

        override func viewDidLoad() {
            super.viewDidLoad()
        }

        @IBAction func presentToChild(_ sender: UIButton) {
            let childVC =  UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier:"ViewControllerB") as! ViewControllerB
            //Registered delegate
            childVC.delegate = self
            self.present(childVC, animated: true, completion: nil)
        }

        // Implement the delegate method in ViewControllerA
        func sendData(data : String) {
            if data != "" {
                self.dataLabel.text = data
            }
        }
    }

Rails 4: List of available datatypes

You can access this list everytime you want (even if you don't have Internet access) through:

rails generate model -h

Create a variable name with "paste" in R?

In my case the symbols I create (Tax1, Tax2, etc.) already had values but I wanted to use a loop and assign the symbols to another variable. So the above two answers gave me a way to accomplish this. This may be helpful in answering your question as the assignment of a value can take place anytime later.

output=NULL
for(i in 1:8){
   Tax=eval(as.symbol(paste("Tax",i,sep="")))
   L_Data1=L_Data_all[which(L_Data_all$Taxon==Tax[1] | L_Data_all$Taxon==Tax[2] | L_Data_all$Taxon==Tax[3] | L_Data_all$Taxon==Tax[4] | L_Data_all$Taxon==Tax[5]),]
   L_Data=L_Data1$Length[which(L_Data1$Station==Plant[1] | L_Data1$Station==Plant[2])]
   h=hist(L_Data,breaks=breaks,plot=FALSE)
   output=cbind(output,h$counts)
}

How can I make PHP display the error instead of giving me 500 Internal Server Error

If all else fails try moving (i.e. in bash) all files and directories "away" and adding them back one by one.

I just found out that way that my .htaccess file was referencing a non-existant .htpasswd file. (#silly)

Webpack - webpack-dev-server: command not found

For global installation : npm install webpack-dev-server -g

For local installation npm install --save-dev webpack

When you refer webpack in package.json file, it tries to look it in location node_modules\.bin\

After local installation, file wbpack will get created in location: \node_modules\.bin\webpack

How to change the size of the font of a JLabel to take the maximum size

Source Code for Label - How to change Color and Font (in Netbeans)

jLabel1.setFont(new Font("Serif", Font.BOLD, 12));


jLabel1.setForeground(Color.GREEN);

Why can I not create a wheel in python?

Update your setuptools, too.

pip install setuptools --upgrade

If that fails too, you could try with additional --force flag.

How to run a method every X seconds

If you are familiar with RxJava, you can use Observable.interval(), which is pretty neat.

Observable.interval(60, TimeUnits.SECONDS)
          .flatMap(new Function<Long, ObservableSource<String>>() {
                @Override
                public ObservableSource<String> apply(@NonNull Long aLong) throws Exception {
                    return getDataObservable(); //Where you pull your data
                }
            });

The downside of this is that you have to architect polling your data in a different way. However, there are a lot of benefits to the Reactive Programming way:

  1. Instead of controlling your data via a callback, you create a stream of data that you subscribe to. This separates the concern of "polling data" logic and "populating UI with your data" logic so that you do not mix your "data source" code and your UI code.
  2. With RxAndroid, you can handle threads in just 2 lines of code.

    Observable.interval(60, TimeUnits.SECONDS)
          .flatMap(...) // polling data code
          .subscribeOn(Schedulers.newThread()) // poll data on a background thread
          .observeOn(AndroidSchedulers.mainThread()) // populate UI on main thread
          .subscribe(...); // your UI code
    

Please check out RxJava. It has a high learning curve but it will make handling asynchronous calls in Android so much easier and cleaner.

How can I force Python's file.write() to use the same newline format in Windows as in Linux ("\r\n" vs. "\n")?

You need to open the file in binary mode i.e. wb instead of w. If you don't, the end of line characters are auto-converted to OS specific ones.

Here is an excerpt from Python reference about open().

The default is to use text mode, which may convert '\n' characters to a platform-specific representation on writing and back on reading.

How to convert byte array to string and vice versa?

private static String toHexadecimal(byte[] digest){
        String hash = "";
    for(byte aux : digest) {
        int b = aux & 0xff;
        if (Integer.toHexString(b).length() == 1) hash += "0";
        hash += Integer.toHexString(b);
    }
    return hash;
}

Is a Python list guaranteed to have its elements stay in the order they are inserted in?

I suppose one thing that may be concerning you is whether or not the entries could change, so that the 2 becomes a different number, for instance. You can put your mind at ease here, because in Python, integers are immutable, meaning they cannot change after they are created.

Not everything in Python is immutable, though. For example, lists are mutable---they can change after being created. So for example, if you had a list of lists

>>> a = [[1], [2], [3]]
>>> a[0].append(7)
>>> a
[[1, 7], [2], [3]]

Here, I changed the first entry of a (I added 7 to it). One could imagine shuffling things around, and getting unexpected things here if you are not careful (and indeed, this does happen to everyone when they start programming in Python in some way or another; just search this site for "modifying a list while looping through it" to see dozens of examples).

It's also worth pointing out that x = x + [a] and x.append(a) are not the same thing. The second one mutates x, and the first one creates a new list and assigns it to x. To see the difference, try setting y = x before adding anything to x and trying each one, and look at the difference the two make to y.

WAMP 403 Forbidden message on Windows 7

I have found that if you are using ammps that for some reason its always forbidden when its in your root folder so i put it in the directory above my root folder and made a alias in the httpd.conf using this

Alias /phpmyadmin "C:/Program Files (x86)/Ampps/phpMyAdmin"

please note i am using ammps and i dont know for sure if it will work for others but its worth a try ;)

Make function wait until element exists

Here's a minor improvement over Jamie Hutber's answer

const checkElement = async selector => {
  while ( document.querySelector(selector) === null) {
    await new Promise( resolve =>  requestAnimationFrame(resolve) )
  }
  return document.querySelector(selector); 
};

To use:

checkElement('.myElement').then((selector) => {
  console.log(selector);
});

jQuery - hashchange event

You can detect if the browser supports the event by:

if ("onhashchange" in window) {
  //...
}

See also:

Using jQuery's ajax method to retrieve images as a blob

You can't do this with jQuery ajax, but with native XMLHttpRequest.

var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function(){
    if (this.readyState == 4 && this.status == 200){
        //this.response is what you're looking for
        handler(this.response);
        console.log(this.response, typeof this.response);
        var img = document.getElementById('img');
        var url = window.URL || window.webkitURL;
        img.src = url.createObjectURL(this.response);
    }
}
xhr.open('GET', 'http://jsfiddle.net/img/logo.png');
xhr.responseType = 'blob';
xhr.send();      

EDIT

So revisiting this topic, it seems it is indeed possible to do this with jQuery 3

_x000D_
_x000D_
jQuery.ajax({_x000D_
        url:'https://images.unsplash.com/photo-1465101108990-e5eac17cf76d?ixlib=rb-0.3.5&q=85&fm=jpg&crop=entropy&cs=srgb&ixid=eyJhcHBfaWQiOjE0NTg5fQ%3D%3D&s=471ae675a6140db97fea32b55781479e',_x000D_
        cache:false,_x000D_
        xhr:function(){// Seems like the only way to get access to the xhr object_x000D_
            var xhr = new XMLHttpRequest();_x000D_
            xhr.responseType= 'blob'_x000D_
            return xhr;_x000D_
        },_x000D_
        success: function(data){_x000D_
            var img = document.getElementById('img');_x000D_
            var url = window.URL || window.webkitURL;_x000D_
            img.src = url.createObjectURL(data);_x000D_
        },_x000D_
        error:function(){_x000D_
            _x000D_
        }_x000D_
    });
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.0.0/jquery.min.js"></script>_x000D_
<img id="img" width=100%>
_x000D_
_x000D_
_x000D_

or

use xhrFields to set the responseType

_x000D_
_x000D_
    jQuery.ajax({_x000D_
            url:'https://images.unsplash.com/photo-1465101108990-e5eac17cf76d?ixlib=rb-0.3.5&q=85&fm=jpg&crop=entropy&cs=srgb&ixid=eyJhcHBfaWQiOjE0NTg5fQ%3D%3D&s=471ae675a6140db97fea32b55781479e',_x000D_
            cache:false,_x000D_
            xhrFields:{_x000D_
                responseType: 'blob'_x000D_
            },_x000D_
            success: function(data){_x000D_
                var img = document.getElementById('img');_x000D_
                var url = window.URL || window.webkitURL;_x000D_
                img.src = url.createObjectURL(data);_x000D_
            },_x000D_
            error:function(){_x000D_
                _x000D_
            }_x000D_
        });
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.0.0/jquery.min.js"></script>_x000D_
    <img id="img" width=100%>
_x000D_
_x000D_
_x000D_

Is it possible to modify a string of char in C?

When you write a "string" in your source code, it gets written directly into the executable because that value needs to be known at compile time (there are tools available to pull software apart and find all the plain text strings in them). When you write char *a = "This is a string", the location of "This is a string" is in the executable, and the location a points to, is in the executable. The data in the executable image is read-only.

What you need to do (as the other answers have pointed out) is create that memory in a location that is not read only--on the heap, or in the stack frame. If you declare a local array, then space is made on the stack for each element of that array, and the string literal (which is stored in the executable) is copied to that space in the stack.

char a[] = "This is a string";

you can also copy that data manually by allocating some memory on the heap, and then using strcpy() to copy a string literal into that space.

char *a = malloc(256);
strcpy(a, "This is a string");

Whenever you allocate space using malloc() remember to call free() when you are finished with it (read: memory leak).

Basically, you have to keep track of where your data is. Whenever you write a string in your source, that string is read only (otherwise you would be potentially changing the behavior of the executable--imagine if you wrote char *a = "hello"; and then changed a[0] to 'c'. Then somewhere else wrote printf("hello");. If you were allowed to change the first character of "hello", and your compiler only stored it once (it should), then printf("hello"); would output cello!)

COALESCE Function in TSQL

declare @store table (store_id varchar(300))
insert into @store 
values ('aa'),('bb'),('cc')
declare @str varchar (4000)
select @str = concat(@str+',',store_id) from @store
select @str

AngularJS ng-if with multiple conditions

OR operator:

<div ng-repeat="k in items">
    <div ng-if="k || 'a' or k == 'b'">
        <!-- SOME CONTENT -->
    </div>
</div>

Even though it is simple enough to read, I hope as a developer you are use better names than 'a' 'k' 'b' etc..

For Example:

<div class="links-group" ng-repeat="group in groups" ng-show="!group.hidden">
    <li ng-if="user.groups.admin || group.title == 'Home Pages'"> 
        <!--Content-->
    </li>
</div>

Another OR example

<p ng-if="group.title != 'Dispatcher News' or group.title != 'Coordinator News'" style="padding: 5px;">No links in group.</p>

AND operator (For those stumbling across this stackoverflow answer looking for an AND instead of OR condition)

<div class="links-group" ng-repeat="group in groups" ng-show="!group.hidden">
    <li ng-if="user.groups.admin && group.title == 'Home Pages'"> 
        <!--Content-->
    </li>
</div>

docker unauthorized: authentication required - upon push with successful login

You can mv the xxx/.docker/config.json file somewhere for handle it. Then try to login again for create new config.json file.

#mv xx/.docker/config.json xx/.docker/config_old.json
#docker login https://index.docker.io/v1/
Login with your Docker ID to push and pull images from Docker Hub. If you don't have a Docker ID, head over to https://hub.docker.com to create one.
Username: YOUR USERNAME
Password: YOUR PASSWORD
WARNING! Your password will be stored unencrypted in /xxx/.docker/config.json.
Configure a credential helper to remove this warning. See https://docs.docker.com/engine/reference/commandline/login/#credentials-store

Login Succeeded

Sql select rows containing part of string

You can use the LIKE operator to compare the content of a T-SQL string, e.g.

SELECT * FROM [table] WHERE [field] LIKE '%stringtosearchfor%'.

The percent character '%' is a wild card- in this case it says return any records where [field] at least contains the value "stringtosearchfor".

ld: framework not found Pods

None of the previous answers pointed out the root problem in my situation. So I hope this may be useful to someone else.

In my case I ended up having to edit my podfile at the root of my project. When I first created my podfile, swift static libraries were not supported. So I had been using use_frameworks! in my podfile under each of my targets as such:

BEFORE

...
target 'targetName' do
   use_frameworks!
   pod 'podName', '~> 0.2'
end

AFTER

...
target 'targetName' do
   pod 'podName', '~> 0.2'
end

I removed use_frameworks! from my podfile which kept installing the frameworks every time I ran pod install. After removing this line, make sure to run pod install again and remove any of the red .framework references from your Frameworks folder in Xcode. (Though mine appeared differently as attached below.)

Image of Removing .framework files that are no longer necessary

You can also read more about use_framework! here.

Get absolute path to workspace directory in Jenkins Pipeline plugin

For me WORKSPACE was a valid property of the pipeline itself. So when I handed over this to a Groovy method as parameter context from the pipeline script itself, I was able to access the correct value using "... ${context.WORKSPACE} ..."

(on Jenkins 2.222.3, Build Pipeline Plugin 1.5.8, Pipeline: Nodes and Processes 2.35)

Delete a dictionary item if the key exists

There is also:

try:
    del mydict[key]
except KeyError:
    pass

This only does 1 lookup instead of 2. However, except clauses are expensive, so if you end up hitting the except clause frequently, this will probably be less efficient than what you already have.

How to make bootstrap 3 fluid layout without horizontal scrollbar

In Bootstrap 3, putting columns immediately under body should give you a fluid layout without horizontal scroll bar

<body>
  <div class="col-md-6">.col-md-6</div>
  <div class="col-md-6">.col-md-6</div>
</body>

When to use reinterpret_cast?

The meaning of reinterpret_cast is not defined by the C++ standard. Hence, in theory a reinterpret_cast could crash your program. In practice compilers try to do what you expect, which is to interpret the bits of what you are passing in as if they were the type you are casting to. If you know what the compilers you are going to use do with reinterpret_cast you can use it, but to say that it is portable would be lying.

For the case you describe, and pretty much any case where you might consider reinterpret_cast, you can use static_cast or some other alternative instead. Among other things the standard has this to say about what you can expect of static_cast (§5.2.9):

An rvalue of type “pointer to cv void” can be explicitly converted to a pointer to object type. A value of type pointer to object converted to “pointer to cv void” and back to the original pointer type will have its original value.

So for your use case, it seems fairly clear that the standardization committee intended for you to use static_cast.

Does a TCP socket connection have a "keep alive"?

Here is some supplemental literature on keepalive which explains it in much finer detail.

http://www.tldp.org/HOWTO/html_single/TCP-Keepalive-HOWTO

Since Java does not allow you to control the actual keepalive times, you can use the examples to change them if you're using a Linux kernel (or proc based OS).

Iterating over each line of ls -l output

The read(1) utility along with output redirection of the ls(1) command will do what you want.

Code formatting shortcuts in Android Studio for Operation Systems

Really, I went to this thread because of my Ubuntu locks screen after this shortcut Ctrl + Alt + L. So if you are have the same problem just go to the Settings - Keyboard - Shortcuts - System and change the default shortcut for the "Lock screen".

How to convert a pymongo.cursor.Cursor into a dict?

to_dict() Convert a SON document to a normal Python dictionary instance.

This is trickier than just dict(...) because it needs to be recursive.

http://api.mongodb.org/python/current/api/bson/son.html

Can't access Eclipse marketplace

I know it's a bit old but I ran in the same problem today. I wanted to install eclipse on my vm with xubuntu. Because I've had problems with the latest eclipse version 2019-06 I tried with Oxygen. So I went to eclipse.org and downloaded oxygen. When running oxygen, the problem with merketplace not reachable occurs. So I downloaded the eclipse installer not immediatly the oxygen. After that I can use eclipse as expectet ( all versions)

How to print struct variables in console?

Visit here to see the complete code. Here you will also find a link for an online terminal where the complete code can be run and the program represents how to extract structure's information(field's name their type & value). Below is the program snippet that only prints the field names.

package main

import "fmt"
import "reflect"

func main() {
    type Book struct {
        Id    int
        Name  string
        Title string
    }

    book := Book{1, "Let us C", "Enjoy programming with practice"}
    e := reflect.ValueOf(&book).Elem()

    for i := 0; i < e.NumField(); i++ {
        fieldName := e.Type().Field(i).Name
        fmt.Printf("%v\n", fieldName)
    }
}

/*
Id
Name
Title
*/

how to change the dist-folder path in angular-cli after 'ng build'

You can update the output folder in .angular-cli.json:

"outDir": "./location/toYour/dist"

Difference between using gradlew and gradle

gradlew is a wrapper(w - character) that uses gradle.

Under the hood gradlew performs three main things:

  • Download and install the correct gradle version
  • Parse the arguments
  • Call a gradle task

Using Gradle Wrapper we can distribute/share a project to everybody to use the same version and Gradle's functionality(compile, build, install...) even if it has not been installed.

To create a wrapper run:

gradle wrapper

This command generate:

gradle-wrapper.properties will contain the information about the Gradle distribution

*./ Is used on Unix to specify the current directory

How to call a function, PostgreSQL

I had this same issue while trying to test a very similar function that uses a SELECT statement to decide if a INSERT or an UPDATE should be done. This function was a re-write of a T-SQL stored procedure.
When I tested the function from the query window I got the error "query has no destination for result data". I finally figured out that because I used a SELECT statement inside the function that I could not test the function from the query window until I assigned the results of the SELECT to a local variable using an INTO statement. This fixed the problem.

If the original function in this thread was changed to the following it would work when called from the query window,

$BODY$
DECLARE
   v_temp integer;
BEGIN
SELECT 1 INTO v_temp
FROM "USERS"
WHERE "userID" = $1;

Getting time difference between two times in PHP

You can use strtotime() for time calculation. Here is an example:

$checkTime = strtotime('09:00:59');
echo 'Check Time : '.date('H:i:s', $checkTime);
echo '<hr>';

$loginTime = strtotime('09:01:00');
$diff = $checkTime - $loginTime;
echo 'Login Time : '.date('H:i:s', $loginTime).'<br>';
echo ($diff < 0)? 'Late!' : 'Right time!'; echo '<br>';
echo 'Time diff in sec: '.abs($diff);

echo '<hr>';

$loginTime = strtotime('09:00:59');
$diff = $checkTime - $loginTime;
echo 'Login Time : '.date('H:i:s', $loginTime).'<br>';
echo ($diff < 0)? 'Late!' : 'Right time!';

echo '<hr>';

$loginTime = strtotime('09:00:00');
$diff = $checkTime - $loginTime;
echo 'Login Time : '.date('H:i:s', $loginTime).'<br>';
echo ($diff < 0)? 'Late!' : 'Right time!';

Demo

Check the already-asked question - how to get time difference in minutes:

Subtract the past-most one from the future-most one and divide by 60.

Times are done in unix format so they're just a big number showing the number of seconds from January 1 1970 00:00:00 GMT

Get the height and width of the browser viewport without scrollbars using jquery?

Don't use jQuery, just use javascript for correct result:

This includes scrollbar width/height:

_x000D_
_x000D_
var windowWidth = window.innerWidth;_x000D_
var windowHeight = window.innerHeight;_x000D_
_x000D_
alert('viewport width is: '+ windowWidth + ' and viewport height is:' + windowHeight);
_x000D_
_x000D_
_x000D_

This excludes scrollbar width/height:

_x000D_
_x000D_
var widthWithoutScrollbar = document.body.clientWidth;_x000D_
var heightWithoutScrollbar = document.body.clientHeight;_x000D_
_x000D_
alert('viewport width is: '+ widthWithoutScrollbar + ' and viewport height is:' + heightWithoutScrollbar);
_x000D_
_x000D_
_x000D_

How to view the contents of an Android APK file?

It's shipped with Android Studio now. Just go to Build/Analyze APK... then select your APK :)

enter image description here

How do I clear the previous text field value after submitting the form with out refreshing the entire page?

.val() or .value is IMHO the best solution because it's useful with Ajax. And .reset() only works after page reload and APIs using Ajax never refresh pages unless it's triggered by a different script.

AngularJS event on window innerWidth size change

We could do it with jQuery:

$(window).resize(function(){
    alert(window.innerWidth);

    $scope.$apply(function(){
       //do something to update current scope based on the new innerWidth and let angular update the view.
    });
});

Be aware that when you bind an event handler inside scopes that could be recreated (like ng-repeat scopes, directive scopes,..), you should unbind your event handler when the scope is destroyed. If you don't do this, everytime when the scope is recreated (the controller is rerun), there will be 1 more handler added causing unexpected behavior and leaking.

In this case, you may need to identify your attached handler:

  $(window).on("resize.doResize", function (){
      alert(window.innerWidth);

      $scope.$apply(function(){
          //do something to update current scope based on the new innerWidth and let angular update the view.
      });
  });

  $scope.$on("$destroy",function (){
      $(window).off("resize.doResize"); //remove the handler added earlier
  });

In this example, I'm using event namespace from jQuery. You could do it differently according to your requirements.

Improvement: If your event handler takes a bit long time to process, to avoid the problem that the user may keep resizing the window, causing the event handlers to be run many times, we could consider throttling the function. If you use underscore, you can try:

$(window).on("resize.doResize", _.throttle(function (){
    alert(window.innerWidth);

    $scope.$apply(function(){
        //do something to update current scope based on the new innerWidth and let angular update the view.
    });
},100));

or debouncing the function:

$(window).on("resize.doResize", _.debounce(function (){
     alert(window.innerWidth);

     $scope.$apply(function(){
         //do something to update current scope based on the new innerWidth and let angular update the view.
     });
},100));

Difference Between throttling and debouncing a function

How do I make an HTML text box show a hint when empty?

Use jQuery Form Notifier - it is one of the most popular jQuery plugins and doesn't suffer from the bugs some of the other jQuery suggestions here do (for example, you can freely style the watermark, without worrying if it will get saved to the database).

jQuery Watermark uses a single CSS style directly on the form elements (I noticed that CSS font-size properties applied to the watermark also affected the text boxes -- not what I wanted). The plus with jQuery Watermark is you can drag-drop text into fields (jQuery Form Notifier doesn't allow this).

Another one suggested by some others (the one at digitalbrush.com), will accidentally submit the watermark value to your form, so I strongly recommend against it.

What is the OR operator in an IF statement

Or is ||

And is &&

Update for changed question:

You need to specify what you are comparing against in each logical section of the if statement.

if (title == "User greeting" || title == "User name") 
{
    // do stuff
}

How to change indentation mode in Atom?

This is built into core: See Settings ? Tab Type and choose auto:

When set to "auto", the editor auto-detects the tab type based on the contents of the buffer (it uses the first leading whitespace on a non-comment line), or uses the value of the Soft Tabs config setting if auto-detection fails.

You may also want to take a look at the Auto Detect Indentation package. From the docs:

Automatically detect indentation of opened files. It looks at each opened file and sets file specific tab settings (hard/soft tabs, tab length) based on the content of the file instead of always using the editor defaults.

You might have atom configured to use 4 spaces for tabs but open a rails project which defaults to 2 spaces. Without this package, you would have to change your tabstop settings globally or risk having inconsistent lead spacing in your files.

Create a pointer to two-dimensional array

You can always avoid fiddling around with the compiler by declaring the array as linear and doing the (row,col) to array index calculation by yourself.

static uint8_t l_matrix[200];

void test(int row, int col, uint8_t val)

{

   uint8_t* matrix_ptr = l_matrix;
   matrix_ptr [col+y*row] = val; // to assign a value

}

this is what the compiler would have done anyway.

Convert the values in a column into row names in an existing data frame

As of 2016 you can also use the tidyverse.

library(tidyverse)
samp %>% remove_rownames %>% column_to_rownames(var="names")

".addEventListener is not a function" why does this error occur?

The problem with your code is that the your script is executed prior to the html element being available. Because of the that var comment is an empty array.

So you should move your script after the html element is available.

Also, getElementsByClassName returns html collection, so if you need to add event Listener to an element, you will need to do something like following

comment[0].addEventListener('click' , showComment , false ) ; 

If you want to add event listener to all the elements, then you will need to loop through them

for (var i = 0 ; i < comment.length; i++) {
   comment[i].addEventListener('click' , showComment , false ) ; 
}

How to pass variables from one php page to another without form?

use the get method in the url. If you want to pass over a variable called 'phone' as 0001112222:

<a href='whatever.php?phone=0001112222'>click</a>

then on the next page (whatever.php) you can access this var via:

$_GET['phone']

How to exclude subdirectories in the destination while using /mir /xd switch in robocopy

Rather than creating empty directories in source to exclude, you can supply the full destination path to the /XD switch to have the destination directories untouched

robocopy "%SOURCE_PATH%" "%DEST_PATH%" /MIR /XD "%DEST_PATH%"\hq04s2dba301

How to set gradle home while importing existing project in Android studio

For OSX, if going to Finder, navigate to this category: /usr/local/opt/ if you do not see gradle folder, install your grandle version manually:

https://services.gradle.org/distributions/gradle-5.4.1-all.zip

https://services.gradle.org/distributions/gradle-4.4.1-all.zip

If you are looking for specific Gradle version, simply change the version number from the zip links above, unzip and add that in the Gradle folder /usr/local/opt/gradle

java.rmi.ConnectException: Connection refused to host: 127.0.1.1;

When I got the same error on my machine ("connection is refused"), the reason was that I had defined the following on the server side:

 Naming.rebind("rmi://localhost:8080/AddService"
   ,addService); 

Thus the server binds both the IP = 127.0.0.1 and the port 8080.

But on the client side I had used:

AddServerInterface st = (AddServerInterface)Naming.lookup("rmi://localhost"
                        +"/AddService");

Thus I forgot to add the port number after the localhost, so I rewrote the above command and added the port number 8080 as follows:

AddServerInterface st = (AddServerInterface)Naming.lookup("rmi://localhost:8080"
                        +"/AddService");

and everything worked fine.

If a folder does not exist, create it

As others have said, use System.IO.Directory.CreateDirectory.

But, you don't need to check if it exists first. From the documentation:

Any and all directories specified in path are created, unless they already exist or unless some part of path is invalid. If the directory already exists, this method does not create a new directory, but it returns a DirectoryInfo object for the existing directory.

How to convert Set to Array?

Perhaps to late to the party, but you could just do the following:

const set = new Set(['a', 'b']);
const values = set.values();
const array = Array.from(values);

This should work without problems in browsers that have support for ES6 or if you have a shim that correctly polyfills the above functionality.

Edit: Today you can just use what @c69 suggests:

const set = new Set(['a', 'b']);
const array = [...set]; // or Array.from(set)

what is the difference between $_SERVER['REQUEST_URI'] and $_GET['q']?

Given this example url:

http://www.example.com/some-dir/yourpage.php?q=bogus&n=10

$_SERVER['REQUEST_URI'] will give you:

/some-dir/yourpage.php?q=bogus&n=10

Whereas $_GET['q'] will give you:

bogus

In other words, $_SERVER['REQUEST_URI'] will hold the full request path including the querystring. And $_GET['q'] will give you the value of parameter q in the querystring.

Read CSV file column by column

I am sorry, but none of these answers provide an optimal solution. If you use a library such as OpenCSV you will have to write a lot of code to handle special cases to extract information from specific columns.

For example, if you have rows with less columns than what you're after, you'll have to write a lot of code to handle it. Using the OpenCSV example:

  CSVReader reader = new CSVReader(new FileReader(strFile));
  String [] nextLine;
  while ((nextLine = reader.readNext()) != null) {
       //let's say you are interested in getting columns 20, 30, and 40
       String[] outputRow = new String[3];
       if(parsedRow.length < 40){
            outputRow[2] = null;
       } else {
            outputRow[2] = parsedRow[40]
       }
       if(parsedRow.length < 30){
            outputRow[1] = null;
       } else {
            outputRow[1] = parsedRow[30]
       }
       if(parsedRow.length < 20){
            outputRow[0] = null;
       } else {
            outputRow[0] = parsedRow[20]
       }

  }

This is a lot of code for a simple requirement. It gets worse if you are trying to get values of columns by name. You should use a more modern parser such as the one provided by uniVocity-parsers.

To reliably and easily get the columns you want, simply write:

CsvParserSettings settings = new CsvParserSettings();
parserSettings.selectIndexes(20, 30, 40);
CsvParser parser = new CsvParser(settings);
List<String[]> allRows = parser.parseAll(new FileReader(yourFile));

Disclosure: I am the author of this library. It's open-source and free (Apache V2.0 license).

Extending from two classes

Yes. slandau is right. Java does not allow extending from several classes.

What you want is probably public class Main extends ListActivity implements ControlMenu. I am guessing you are trying to make a list.

Hope that helps.

How can I create a correlation matrix in R?

The cor function will use the columns of the matrix in the calculation of correlation. So, the number of rows must be the same between your matrix x and matrix y. Ex.:

set.seed(1)
x <- matrix(rnorm(20), nrow=5, ncol=4)
y <- matrix(rnorm(15), nrow=5, ncol=3)
COR <- cor(x,y)
COR
image(x=seq(dim(x)[2]), y=seq(dim(y)[2]), z=COR, xlab="x column", ylab="y column")
text(expand.grid(x=seq(dim(x)[2]), y=seq(dim(y)[2])), labels=round(c(COR),2))

enter image description here

Edit:

Here is an example of custom row and column labels on a correlation matrix calculated with a single matrix:

png("corplot.png", width=5, height=5, units="in", res=200)
op <- par(mar=c(6,6,1,1), ps=10)
COR <- cor(iris[,1:4])
image(x=seq(nrow(COR)), y=seq(ncol(COR)), z=cor(iris[,1:4]), axes=F, xlab="", ylab="")
text(expand.grid(x=seq(dim(COR)[1]), y=seq(dim(COR)[2])), labels=round(c(COR),2))
box()
axis(1, at=seq(nrow(COR)), labels = rownames(COR), las=2)
axis(2, at=seq(ncol(COR)), labels = colnames(COR), las=1)
par(op)
dev.off()

enter image description here

Prevent double submission of forms in jQuery

I solved a very similar issue using:

$("#my_form").submit(function(){
    $('input[type=submit]').click(function(event){
        event.preventDefault();
    });
});

Winforms issue - Error creating window handle

I got same error in my application.I am loading many controls in single page.In button click event i am clearing the controls.clearing the controls doesnot release the controls from memory.So dispose the controls from memory. I just commented controls.clear() method and include few lines of code to dispose the controls. Something like this

for each ctl as control in controlcollection

ctl.dispose()

Next

How to pass parameters to the DbContext.Database.ExecuteSqlCommand method?

If your underlying database data types are varchar then you should stick with the approach below. Otherwise the query would have a huge performance impact.

var firstName = new SqlParameter("@firstName", System.Data.SqlDbType.VarChar, 20)
                            {
                                Value = "whatever"
                            };

var id = new SqlParameter("@id", System.Data.SqlDbType.Int)
                            {
                                Value = 1
                            };
ctx.Database.ExecuteSqlCommand(@"Update [User] SET FirstName = @firstName WHERE Id = @id"
                               , firstName, id);

You can check Sql profiler to see the difference.

Sending SMS from PHP

You need to subscribe to a SMS gateway. There are thousands of those (try searching with google) and they are usually not free. For example this one has support for PHP.

Find the files existing in one directory but not in the other

Meld (http://meldmerge.org/) does a great job at comparing directories and the files within.

Meld comparing directories

Has been compiled by a more recent version of the Java Runtime (class file version 57.0)

I have run into this issue When I recently upgraded my IntelliJ version to 2020.3. I had to disable a plugin to solve this issue. The name of the plugin is Thrift Support.

Steps to disable the plugin is following:

  1. Open the Preferences of IntelliJ. You can do so by clicking on Command + , in mac.
  2. Navigate to plugins.
  3. Search for the Thrift Support plugin in the search window. Click on the tick box icon to deselect it.
  4. Click on the Apply icon.
  5. See this image for reference Disable_Thrift_support_plugin

For more detail please refer to this link java.lang.UnsupportedClassVersionError 2020.3 version intellij. I found this comment in the above link which has worked for me.

bin zhao commented 31 Dec 2020 08:00 @Lejia Chen @Tobias Schulmann Workflow My IDEA3.X didn't installed Erlang plugin, I disabled Thrift Support 1.4.0 and it worked. Both IDEA 3.0 and 3.1 have the same problem.

How to check for null in Twig?

you can use the following code to check whether

{% if var is defined %}

var is variable is SET

{% endif %}

MySQL: ALTER TABLE if column not exists

Add field if not exist:

CALL addFieldIfNotExists ('settings', 'multi_user', 'TINYINT(1) NOT NULL DEFAULT 1');

addFieldIfNotExists code:

DELIMITER $$

DROP PROCEDURE IF EXISTS addFieldIfNotExists 
$$

DROP FUNCTION IF EXISTS isFieldExisting 
$$

CREATE FUNCTION isFieldExisting (table_name_IN VARCHAR(100), field_name_IN VARCHAR(100)) 
RETURNS INT
RETURN (
    SELECT COUNT(COLUMN_NAME) 
    FROM INFORMATION_SCHEMA.columns 
    WHERE TABLE_SCHEMA = DATABASE() 
    AND TABLE_NAME = table_name_IN 
    AND COLUMN_NAME = field_name_IN
)
$$

CREATE PROCEDURE addFieldIfNotExists (
    IN table_name_IN VARCHAR(100)
    , IN field_name_IN VARCHAR(100)
    , IN field_definition_IN VARCHAR(100)
)
BEGIN

    SET @isFieldThere = isFieldExisting(table_name_IN, field_name_IN);
    IF (@isFieldThere = 0) THEN

        SET @ddl = CONCAT('ALTER TABLE ', table_name_IN);
        SET @ddl = CONCAT(@ddl, ' ', 'ADD COLUMN') ;
        SET @ddl = CONCAT(@ddl, ' ', field_name_IN);
        SET @ddl = CONCAT(@ddl, ' ', field_definition_IN);

        PREPARE stmt FROM @ddl;
        EXECUTE stmt;
        DEALLOCATE PREPARE stmt;

    END IF;

END;
$$

Spring boot - configure EntityManager

With Spring Boot its not necessary to have any config file like persistence.xml. You can configure with annotations Just configure your DB config for JPA in the

application.properties

spring.datasource.driverClassName=oracle.jdbc.driver.OracleDriver
spring.datasource.url=jdbc:oracle:thin:@DB...
spring.datasource.username=username
spring.datasource.password=pass

spring.jpa.database-platform=org.hibernate.dialect....
spring.jpa.show-sql=true

Then you can use CrudRepository provided by Spring where you have standard CRUD transaction methods. There you can also implement your own SQL's like JPQL.

@Transactional
public interface ObjectRepository extends CrudRepository<Object, Long> {
...
}

And if you still need to use the Entity Manager you can create another class.

public class ObjectRepositoryImpl implements ObjectCustomMethods{

    @PersistenceContext
    private EntityManager em;

}

This should be in your pom.xml

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.2.5.RELEASE</version>
</parent>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-jpa</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-orm</artifactId>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>4.3.11.Final</version>
    </dependency>
</dependencies>

Perform a Shapiro-Wilk Normality Test

You are applying shapiro.test() to a data.frame instead of the column. Try the following:

shapiro.test(heisenberg$HWWIchg)

Convert/cast an stdClass object to another class

And yet another approach using the decorator pattern and PHPs magic getter & setters:

// A simple StdClass object    
$stdclass = new StdClass();
$stdclass->foo = 'bar';

// Decorator base class to inherit from
class Decorator {

    protected $object = NULL;

    public function __construct($object)
    {
       $this->object = $object;  
    }

    public function __get($property_name)
    {
        return $this->object->$property_name;   
    }

    public function __set($property_name, $value)
    {
        $this->object->$property_name = $value;   
    }
}

class MyClass extends Decorator {}

$myclass = new MyClass($stdclass)

// Use the decorated object in any type-hinted function/method
function test(MyClass $object) {
    echo $object->foo . '<br>';
    $object->foo = 'baz';
    echo $object->foo;   
}

test($myclass);

scale Image in an UIButton to AspectFit?

1 - clear Button default text (important)

2 - set alignment like image

3 - set content mode like image

enter image description here

How do I parse command line arguments in Java?

I know most people here are going to find 10 million reasons why they dislike my way, but nevermind. I like to keep things simple, so I just separate the key from the value using a '=' and store them in a HashMap like this:

Map<String, String> argsMap = new HashMap<>();
for (String arg: args) {
    String[] parts = arg.split("=");
    argsMap.put(parts[0], parts[1]);
} 

You could always maintain a list with the arguments you are expecting, to help the user in case he forgot an argument or used a wrong one... However, if you want too many features this solution is not for you anyway.

How to set null to a GUID property

Guid? myGuidVar = (Guid?)null;

It could be. Unnecessary casting not required.

Guid? myGuidVar = null;

How can I ask the Selenium-WebDriver to wait for few seconds in Java?

Using Thread.sleep(2000); is an unconditional wait. If your test loads faster you will still have to wait. So in principle using implicitlyWait is the better solution.

However, I don't see why implicitlyWait does not work in your case. Did you measure if the findElement actually takes two seconds before throwing an exception. If so, can you try to use WebDriver's conditional wait as described in this answer?

Google Play Services Missing in Emulator (Android 4.4.2)

google play service is just a library to create application but in order to use application that use google play service library , you need to install google play in your emulator.and for that it need the unique device id. and device id is only on the real device not have on emulator. so for testing it , you need real android device.

How to use hex() without 0x in Python?

Old style string formatting:

In [3]: "%02x" % 127
Out[3]: '7f'

New style

In [7]: '{:x}'.format(127)
Out[7]: '7f'

Using capital letters as format characters yields uppercase hexadecimal

In [8]: '{:X}'.format(127)
Out[8]: '7F'

Docs are here.

How to extract base URL from a string in JavaScript?

WebKit-based browsers, Firefox as of version 21 and current versions of Internet Explorer (IE 10 and 11) implement location.origin.

location.origin includes the protocol, the domain and optionally the port of the URL.

For example, location.origin of the URL http://www.sitename.com/article/2009/09/14/this-is-an-article/ is http://www.sitename.com.

To target browsers without support for location.origin use the following concise polyfill:

if (typeof location.origin === 'undefined')
    location.origin = location.protocol + '//' + location.host;

Jquery assiging class to th in a table

You had thead in your selector, but there is no thead in your table. Also you had your selectors backwards. As you mentioned above, you wanted to be adding the tr class to the th, not vice-versa (although your comment seems to contradict what you wrote up above).

$('tr th').each(function(index){     if($('tr td').eq(index).attr('class') != ''){         // get the class of the td         var tdClass = $('tr td').eq(index).attr('class');         // add it to this th         $(this).addClass(tdClass );     } }); 

Fiddle

fatal: early EOF fatal: index-pack failed

Tried most of the answers here, I got the error with the PUTTY SSH Client with all possible constellations.

Once I switched to OpenSSH the error was gone (remove the Environment Variable GIT_SSH and restart the git bash).

I was using a new machine and newest git versions. On many other/older machines (AWS as well) it did work as expected with PUTTY as well without any git configuration.

How to concatenate strings in twig

Whenever you need to use a filter with a concatenated string (or a basic math operation) you should wrap it with ()'s. Eg.:

{{ ('http://' ~ app.request.host) | url_encode }}

Unexpected character encountered while parsing value

I had a similar error and thought I'd answer in case anyone was having something similar. I was looping over a directory of json files and deserializing them but was getting this same error.

The problem was that it was trying to grab hidden files as well. Make sure the file you're passing in is a .json file. I'm guessing it'll handle text as well. Hope this helps.

Creating and playing a sound in swift

Handy Swift extension:

import AudioToolbox

extension SystemSoundID {
    static func playFileNamed(fileName: String, withExtenstion fileExtension: String) {
        var sound: SystemSoundID = 0
        if let soundURL = NSBundle.mainBundle().URLForResource(fileName, withExtension: fileExtension) {
            AudioServicesCreateSystemSoundID(soundURL, &sound)
            AudioServicesPlaySystemSound(sound)
        }
    }
}

Then, from anywhere in your app (remember to import AudioToolbox), you can call

SystemSoundID.playFileNamed("sound", withExtenstion: "mp3")

to play "sound.mp3"

Is arr.__len__() the preferred way to get the length of an array in Python?

Python uses duck typing: it doesn't care about what an object is, as long as it has the appropriate interface for the situation at hand. When you call the built-in function len() on an object, you are actually calling its internal __len__ method. A custom object can implement this interface and len() will return the answer, even if the object is not conceptually a sequence.

For a complete list of interfaces, have a look here: http://docs.python.org/reference/datamodel.html#basic-customization

Percentage calculation

With C# String formatting you can avoid the multiplication by 100 as it will make the code shorter and cleaner especially because of less brackets and also the rounding up code can be avoided.

(current / maximum).ToString("0.00%");

// Output - 16.67%

How to properly and completely close/reset a TcpClient connection?

Despite having all the appropriate using statements, calling Close, having some exponential back off logic and recreating the TcpClient I've still been seeing issues where the application cannot recover the TCP connection without an application restart. It keeps failing with a System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.

But there is an option LingerState on the TcpClient that appears it may have solved the issue (might not know for a few months as my own hardware setup only fails about that often!). See MSDN.

// This discards any pending data and Winsock resets the connection.
LingerOption lingerOption = new LingerOption(true, 0);

using (var tcpClient = new TcpClient 
       {SendTimeout = 2000, ReceiveTimeout = 2000, LingerState = lingerOption })
   ...

Importing PNG files into Numpy?

I changed a bit and it worked like this, dumped into one single array, provided all the images are of same dimensions.

png = []
for image_path in glob.glob("./train/*.png"):
    png.append(misc.imread(image_path))    

im = np.asarray(png)

print 'Importing done...', im.shape

Maven: How to change path to target directory from command line?

Colin is correct that a profile should be used. However, his answer hard-codes the target directory in the profile. An alternate solution would be to add a profile like this:

    <profile>
        <id>alternateBuildDir</id>
        <activation>
            <property>
                <name>alt.build.dir</name>
            </property>
        </activation>
        <build>
            <directory>${alt.build.dir}</directory>
        </build>
    </profile>

Doing so would have the effect of changing the build directory to whatever is given by the alt.build.dir property, which can be given in a POM, in the user's settings, or on the command line. If the property is not present, the compilation will happen in the normal target directory.

How do you append rows to a table using jQuery?

I'm assuming you want to add this row to the <tbody> element, and simply using append() on the <table> will insert the <tr> outside the <tbody>, with perhaps undesirable results.

$('a').click(function() {
   $('#myTable tbody').append('<tr class="child"><td>blahblah</td></tr>');
});

EDIT: Here is the complete source code, and it does indeed work: (Note the $(document).ready(function(){});, which was not present before.

<html>
<head>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.1/jquery.min.js"></script>
<script type="text/javascript">
$(document).ready(function() {
    $('a').click(function() {
       $('#myTable tbody').append('<tr class="child"><td>blahblah</td></tr>');
    });
});
</script>
<title></title>
</head>
<body>
<a href="javascript:void(0);">Link</a>
<table id="myTable">
  <tbody>
    <tr>
      <td>test</td>
    </tr>
  </tbody>
</table>
</body>
</html>

Make the current Git branch a master branch

Make sure everything is pushed up to your remote repository (GitHub):

git checkout main

Overwrite "main" with "better_branch":

git reset --hard better_branch

Force the push to your remote repository:

git push -f origin main

How to use \n new line in VB msgbox() ...?

Use the command "vbNewLine"

Example

Hello & vbNewLine & "World"

will show up as Hello on one line and World on another

Evaluate a string with a switch in C++

As said before, switch can be used only with integer values. So, you just need to convert your "case" values to integer. You can achieve it by using constexpr from c++11, thus some calls of constexpr functions can be calculated in compile time.

something like that...

switch (str2int(s))
{
  case str2int("Value1"):
    break;
  case str2int("Value2"):
    break;
}

where str2int is like (implementation from here):

constexpr unsigned int str2int(const char* str, int h = 0)
{
    return !str[h] ? 5381 : (str2int(str, h+1) * 33) ^ str[h];
}

Another example, the next function can be calculated in compile time:

constexpr int factorial(int n)
{
    return n <= 1 ? 1 : (n * factorial(n-1));
}  

int f5{factorial(5)};
// Compiler will run factorial(5) 
// and f5 will be initialized by this value. 
// so programm instead of wasting time for running function, 
// just will put the precalculated constant to f5 

How can I change my default database in SQL Server without using MS SQL Server Management Studio?

If you use windows authentication, and you don't know a password to login as a user via username and password, you can do this: on the login-screen on SSMS click options at the bottom right, then go to the connection properties tab. Then you can type in manually the name of another database you have access to, over where it says , which will let you connect. Then follow the other advice for changing your default database

https://gyazo.com/c3d04c600311c08cb685bb668b569a67

Loop through an array of strings in Bash?

I loop through an array of my projects for a git pull update:

#!/bin/sh
projects="
web
ios
android
"
for project in $projects do
    cd  $HOME/develop/$project && git pull
end

How can I discover the "path" of an embedded resource?

I use the following method to grab embedded resources:

    protected static Stream GetResourceStream(string resourcePath)
    {
        Assembly assembly = Assembly.GetExecutingAssembly();
        List<string> resourceNames = new List<string>(assembly.GetManifestResourceNames());

        resourcePath = resourcePath.Replace(@"/", ".");
        resourcePath = resourceNames.FirstOrDefault(r => r.Contains(resourcePath));

        if (resourcePath == null)
            throw new FileNotFoundException("Resource not found");

        return assembly.GetManifestResourceStream(resourcePath);
    }

I then call this with the path in the project:

GetResourceStream(@"DirectoryPathInLibrary/Filename")

How can I restart a Java application?

Strictly speaking, a Java program cannot restart itself since to do so it must kill the JVM in which it is running and then start it again, but once the JVM is no longer running (killed) then no action can be taken.

You could do some tricks with custom classloaders to load, pack, and start the AWT components again but this will likely cause lots of headaches with regard to the GUI event loop.

Depending on how the application is launched, you could start the JVM in a wrapper script which contains a do/while loop, which continues while the JVM exits with a particular code, then the AWT app would have to call System.exit(RESTART_CODE). For example, in scripting pseudocode:

DO
  # Launch the awt program
  EXIT_CODE = # Get the exit code of the last process
WHILE (EXIT_CODE == RESTART_CODE)

The AWT app should exit the JVM with something other than the RESTART_CODE on "normal" termination which doesn't require restart.

PowerShell: Run command from script's directory

There are answers with big number of votes, but when I read your question, I thought you wanted to know the directory where the script is, not that where the script is running. You can get the information with powershell's auto variables

$PSScriptRoot - the directory where the script exists, not the target directory the script is running in
$PSCommandPath - the full path of the script

For example, I have $profile script that finds visual studio solution file and start it. I wanted to store the full path, once a solution file is started. But I wanted to save the file where the original script exists. So I used $PsScriptRoot.

HTML to PDF with Node.js

Package

I used html-pdf

Easy to use and allows not only to save pdf as file, but also pipe pdf content to a WriteStream (so I could stream it directly to Google Storage to save there my reports).

Using css + images

It takes css into account. The only problem I faced - it ignored my images. The solution I found was to replace url in src attrribute value by base64, e.g.

<img src="data:image/png;base64,iVBOR...kSuQmCC">

You can do it with your code or to use one of online converters, e.g. https://www.base64-image.de/

Compile valid html code from html fragment + css

  1. I had to get a fragment of my html document (I just appiled .html() method on jQuery selector).
  2. Then I've read the content of the relevant css file.

Using this two values (stored in variables html and css accordingly) I've compiled a valid html code using Template string

var htmlContent = `
<!DOCTYPE html>
<html>
  <head>
    <style>
      ${css}
    </style>
  </head>
  <body id=direct-sellers-bill>
    ${html}
  </body>
</html>`

and passed it to create method of html-pdf.

Using <style> tags in the <body> with other HTML

Because this is HTML is not valid does not have any affect on the outcome ... it just means that the HTML does adhere to the standard (merely for organizational purposes). For the sake of being valid it could have been written this way:

<html>
<head>
<style type="text/css">
  p.first {color:blue}
  p.second {color:green}
</style>
</head>
<body>
<p class="first" style="color:green;">Hello World</p>
<p class="second" style="color:blue;">Hello World</p>

My guess is that the browser applies the last style it comes across.

Laravel check if collection is empty

To determine if there are any results you can do any of the following:

if ($mentor->first()) { } 
if (!$mentor->isEmpty()) { }
if ($mentor->count()) { }
if (count($mentor)) { }
if ($mentor->isNotEmpty()) { }

Notes / References

->first()

https://laravel.com/api/5.7/Illuminate/Database/Eloquent/Collection.html#method_first

isEmpty() https://laravel.com/api/5.7/Illuminate/Database/Eloquent/Collection.html#method_isEmpty

->count()

https://laravel.com/api/5.7/Illuminate/Database/Eloquent/Collection.html#method_count

count($mentors) works because the Collection implements Countable and an internal count() method:

https://laravel.com/api/5.7/Illuminate/Database/Eloquent/Collection.html#method_count

isNotEmpty()

https://laravel.com/docs/5.7/collections#method-isnotempty

So what you can do is :

if (!$mentors->intern->employee->isEmpty()) { }

How to set alignment center in TextBox in ASP.NET?

To center align text

input[type='text'] { text-align:center;}

To center align the textbox in the container that it sits in, apply text-align:center to the container.

How to scanf only integer and repeat reading if the user enters non-numeric characters?

#include <stdio.h>
main()
{
    char str[100];
    int num;
    while(1) {
        printf("Enter a number: ");
        scanf("%[^0-9]%d",str,&num);
        printf("You entered the number %d\n",num);
    }
    return 0;
}

%[^0-9] in scanf() gobbles up all that is not between 0 and 9. Basically it cleans the input stream of non-digits and puts it in str. Well, the length of non-digit sequence is limited to 100. The following %d selects only integers in the input stream and places it in num.

How can I see the current value of my $PATH variable on OS X?

Use the command:

 echo $PATH

and you will see all path:

/Users/name/.rvm/gems/ruby-2.5.1@pe/bin:/Users/name/.rvm/gems/ruby-2.5.1@global/bin:/Users/sasha/.rvm/rubies/ruby-2.5.1/bin:/Users/sasha/.rvm/bin:

Resizing SVG in html?

I have an SVG file in HTML [....] IS there any way to specify that you want an SVG image displayed smaller or larger than it actually is stored in the file system?

SVG graphics, like other creative works, are protected under copyright law in most countries. Depending on jurisdiction, license of the work or whether or not you are the copyright holder you may not be able to modify the SVG without violating copyright law, believe it or not.

But laws are tricky topics and sometimes you just want to get shit done. Therefore you may adjust the scale of the graphic without modifying the work itself using the img tag with width attribute within your HTML.

Using an external HTTP request to specify the size:

<img width="96" src="/path/to/image.svg">

Specifying size in markup using a Data URI:

<img width="96" src="data:image/svg+xml,...">

SVGs can be Optimized for Data URIs to create SVG Favicon images suitable for any size:

<link rel="icon" sizes="any" href="data:image/svg+xml,%3Csvg%20viewBox='0%200%2046%2045'%20xmlns='http://www.w3.org/2000/svg'%3E%3Ctitle%3EAfter%20Dark%3C/title%3E%3Cpath%20d='M.708%2045L23%20.416%2045.292%2045H.708zM35%2038L23%2019%2011%2038h24z'%20fill='%23000'/%3E%3C/svg%3E">

Drop all the tables, stored procedures, triggers, constraints and all the dependencies in one sql statement

try this with sql2012 or above,

this will be help to delete all objects by selected schema

DECLARE @MySchemaName VARCHAR(50)='dbo', @sql VARCHAR(MAX)='';
DECLARE @SchemaName VARCHAR(255), @ObjectName VARCHAR(255), @ObjectType VARCHAR(255), @ObjectDesc VARCHAR(255), @Category INT;

DECLARE cur CURSOR FOR
    SELECT  (s.name)SchemaName, (o.name)ObjectName, (o.type)ObjectType,(o.type_desc)ObjectDesc,(so.category)Category
    FROM    sys.objects o
    INNER JOIN sys.schemas s ON o.schema_id = s.schema_id
    INNER JOIN sysobjects so ON so.name=o.name
    WHERE s.name = @MySchemaName
    AND so.category=0
    AND o.type IN ('P','PC','U','V','FN','IF','TF','FS','FT','PK','TT')

OPEN cur
FETCH NEXT FROM cur INTO @SchemaName,@ObjectName,@ObjectType,@ObjectDesc,@Category

SET @sql='';
WHILE @@FETCH_STATUS = 0 BEGIN    
    IF @ObjectType IN('FN', 'IF', 'TF', 'FS', 'FT') SET @sql=@sql+'Drop Function '+@MySchemaName+'.'+@ObjectName+CHAR(13)
    IF @ObjectType IN('V') SET @sql=@sql+'Drop View '+@MySchemaName+'.'+@ObjectName+CHAR(13)
    IF @ObjectType IN('P') SET @sql=@sql+'Drop Procedure '+@MySchemaName+'.'+@ObjectName+CHAR(13)
    IF @ObjectType IN('U') SET @sql=@sql+'Drop Table '+@MySchemaName+'.'+@ObjectName+CHAR(13)

    --PRINT @ObjectName + ' | ' + @ObjectType
    FETCH NEXT FROM cur INTO @SchemaName,@ObjectName,@ObjectType,@ObjectDesc,@Category
END
CLOSE cur;    
DEALLOCATE cur;
SET @sql=@sql+CASE WHEN LEN(@sql)>0 THEN 'Drop Schema '+@MySchemaName+CHAR(13) ELSE '' END
PRINT @sql
EXECUTE (@sql)

Real time data graphing on a line chart with html5

In order to complete this thread, I would suggest you to look into:

d3.js

This is a library that helps with tons of javascript visualizations. However the learning curve is quite steep.

nvd3.js

A library that makes it easy to create some d3.js visualizations (with limitations, of course).

AngularJs: How to check for changes in file input fields?

This directive pass the selected files as well:

/**
 *File Input - custom call when the file has changed
 */
.directive('onFileChange', function() {
  return {
    restrict: 'A',
    link: function (scope, element, attrs) {
      var onChangeHandler = scope.$eval(attrs.onFileChange);

      element.bind('change', function() {
        scope.$apply(function() {
          var files = element[0].files;
          if (files) {
            onChangeHandler(files);
          }
        });
      });

    }
  };
});

The HTML, how to use it:

<input type="file" ng-model="file" on-file-change="onFilesSelected">

In my controller:

$scope.onFilesSelected = function(files) {
     console.log("files - " + files);
};

SFTP Libraries for .NET

I've searched around and found that this fork of SharpSSH and SSH.NET are the most up to date and best maintained libraries for SFTP (not to be confused with FTPS) communication in .NET. SSH.NET is a clean .NET 4.0 implementation of the SFTP protocol, and I've used it in a couple of solutions with flying colors and great success.

The original SharpSsh seems to be dead and most other solutions either require installation of Windows executables or a bucketload of cash (or worse; both).

Grouping functions (tapply, by, aggregate) and the *apply family

R has many *apply functions which are ably described in the help files (e.g. ?apply). There are enough of them, though, that beginning useRs may have difficulty deciding which one is appropriate for their situation or even remembering them all. They may have a general sense that "I should be using an *apply function here", but it can be tough to keep them all straight at first.

Despite the fact (noted in other answers) that much of the functionality of the *apply family is covered by the extremely popular plyr package, the base functions remain useful and worth knowing.

This answer is intended to act as a sort of signpost for new useRs to help direct them to the correct *apply function for their particular problem. Note, this is not intended to simply regurgitate or replace the R documentation! The hope is that this answer helps you to decide which *apply function suits your situation and then it is up to you to research it further. With one exception, performance differences will not be addressed.

  • apply - When you want to apply a function to the rows or columns of a matrix (and higher-dimensional analogues); not generally advisable for data frames as it will coerce to a matrix first.

    # Two dimensional matrix
    M <- matrix(seq(1,16), 4, 4)
    
    # apply min to rows
    apply(M, 1, min)
    [1] 1 2 3 4
    
    # apply max to columns
    apply(M, 2, max)
    [1]  4  8 12 16
    
    # 3 dimensional array
    M <- array( seq(32), dim = c(4,4,2))
    
    # Apply sum across each M[*, , ] - i.e Sum across 2nd and 3rd dimension
    apply(M, 1, sum)
    # Result is one-dimensional
    [1] 120 128 136 144
    
    # Apply sum across each M[*, *, ] - i.e Sum across 3rd dimension
    apply(M, c(1,2), sum)
    # Result is two-dimensional
         [,1] [,2] [,3] [,4]
    [1,]   18   26   34   42
    [2,]   20   28   36   44
    [3,]   22   30   38   46
    [4,]   24   32   40   48
    

    If you want row/column means or sums for a 2D matrix, be sure to investigate the highly optimized, lightning-quick colMeans, rowMeans, colSums, rowSums.

  • lapply - When you want to apply a function to each element of a list in turn and get a list back.

    This is the workhorse of many of the other *apply functions. Peel back their code and you will often find lapply underneath.

    x <- list(a = 1, b = 1:3, c = 10:100) 
    lapply(x, FUN = length) 
    $a 
    [1] 1
    $b 
    [1] 3
    $c 
    [1] 91
    lapply(x, FUN = sum) 
    $a 
    [1] 1
    $b 
    [1] 6
    $c 
    [1] 5005
    
  • sapply - When you want to apply a function to each element of a list in turn, but you want a vector back, rather than a list.

    If you find yourself typing unlist(lapply(...)), stop and consider sapply.

    x <- list(a = 1, b = 1:3, c = 10:100)
    # Compare with above; a named vector, not a list 
    sapply(x, FUN = length)  
    a  b  c   
    1  3 91
    
    sapply(x, FUN = sum)   
    a    b    c    
    1    6 5005 
    

    In more advanced uses of sapply it will attempt to coerce the result to a multi-dimensional array, if appropriate. For example, if our function returns vectors of the same length, sapply will use them as columns of a matrix:

    sapply(1:5,function(x) rnorm(3,x))
    

    If our function returns a 2 dimensional matrix, sapply will do essentially the same thing, treating each returned matrix as a single long vector:

    sapply(1:5,function(x) matrix(x,2,2))
    

    Unless we specify simplify = "array", in which case it will use the individual matrices to build a multi-dimensional array:

    sapply(1:5,function(x) matrix(x,2,2), simplify = "array")
    

    Each of these behaviors is of course contingent on our function returning vectors or matrices of the same length or dimension.

  • vapply - When you want to use sapply but perhaps need to squeeze some more speed out of your code.

    For vapply, you basically give R an example of what sort of thing your function will return, which can save some time coercing returned values to fit in a single atomic vector.

    x <- list(a = 1, b = 1:3, c = 10:100)
    #Note that since the advantage here is mainly speed, this
    # example is only for illustration. We're telling R that
    # everything returned by length() should be an integer of 
    # length 1. 
    vapply(x, FUN = length, FUN.VALUE = 0L) 
    a  b  c  
    1  3 91
    
  • mapply - For when you have several data structures (e.g. vectors, lists) and you want to apply a function to the 1st elements of each, and then the 2nd elements of each, etc., coercing the result to a vector/array as in sapply.

    This is multivariate in the sense that your function must accept multiple arguments.

    #Sums the 1st elements, the 2nd elements, etc. 
    mapply(sum, 1:5, 1:5, 1:5) 
    [1]  3  6  9 12 15
    #To do rep(1,4), rep(2,3), etc.
    mapply(rep, 1:4, 4:1)   
    [[1]]
    [1] 1 1 1 1
    
    [[2]]
    [1] 2 2 2
    
    [[3]]
    [1] 3 3
    
    [[4]]
    [1] 4
    
  • Map - A wrapper to mapply with SIMPLIFY = FALSE, so it is guaranteed to return a list.

    Map(sum, 1:5, 1:5, 1:5)
    [[1]]
    [1] 3
    
    [[2]]
    [1] 6
    
    [[3]]
    [1] 9
    
    [[4]]
    [1] 12
    
    [[5]]
    [1] 15
    
  • rapply - For when you want to apply a function to each element of a nested list structure, recursively.

    To give you some idea of how uncommon rapply is, I forgot about it when first posting this answer! Obviously, I'm sure many people use it, but YMMV. rapply is best illustrated with a user-defined function to apply:

    # Append ! to string, otherwise increment
    myFun <- function(x){
        if(is.character(x)){
          return(paste(x,"!",sep=""))
        }
        else{
          return(x + 1)
        }
    }
    
    #A nested list structure
    l <- list(a = list(a1 = "Boo", b1 = 2, c1 = "Eeek"), 
              b = 3, c = "Yikes", 
              d = list(a2 = 1, b2 = list(a3 = "Hey", b3 = 5)))
    
    
    # Result is named vector, coerced to character          
    rapply(l, myFun)
    
    # Result is a nested list like l, with values altered
    rapply(l, myFun, how="replace")
    
  • tapply - For when you want to apply a function to subsets of a vector and the subsets are defined by some other vector, usually a factor.

    The black sheep of the *apply family, of sorts. The help file's use of the phrase "ragged array" can be a bit confusing, but it is actually quite simple.

    A vector:

    x <- 1:20
    

    A factor (of the same length!) defining groups:

    y <- factor(rep(letters[1:5], each = 4))
    

    Add up the values in x within each subgroup defined by y:

    tapply(x, y, sum)  
     a  b  c  d  e  
    10 26 42 58 74 
    

    More complex examples can be handled where the subgroups are defined by the unique combinations of a list of several factors. tapply is similar in spirit to the split-apply-combine functions that are common in R (aggregate, by, ave, ddply, etc.) Hence its black sheep status.

How do I temporarily disable triggers in PostgreSQL?

SET session_replication_role = replica; 

It doesn't work with PostgreSQL 9.4 on my Linux machine if i change a table through table editor in pgAdmin and works if i change table through ordinary query. Manual changes in pg_trigger table also don't work without server restart but dynamic query like on postgresql.nabble.com ENABLE / DISABLE ALL TRIGGERS IN DATABASE works. It could be useful when you need some tuning.

For example if you have tables in a particular namespace it could be:

create or replace function disable_triggers(a boolean, nsp character varying) returns void as
$$
declare 
act character varying;
r record;
begin
    if(a is true) then
        act = 'disable';
    else
        act = 'enable';
    end if;

    for r in select c.relname from pg_namespace n
        join pg_class c on c.relnamespace = n.oid and c.relhastriggers = true
        where n.nspname = nsp
    loop
        execute format('alter table %I %s trigger all', r.relname, act); 
    end loop;
end;
$$
language plpgsql;

If you want to disable all triggers with certain trigger function it could be:

create or replace function disable_trigger_func(a boolean, f character varying) returns void as
$$
declare 
act character varying;
r record;
begin
    if(a is true) then
        act = 'disable';
    else
        act = 'enable';
    end if;

    for r in select c.relname from pg_proc p 
        join pg_trigger t on t.tgfoid = p.oid
        join pg_class c on c.oid = t.tgrelid
        where p.proname = f
    loop
        execute format('alter table %I %s trigger all', r.relname, act); 
    end loop;
end;
$$
language plpgsql;

PostgreSQL documentation for system catalogs


There are another control options of trigger firing process:

ALTER TABLE ... ENABLE REPLICA TRIGGER ... - trigger will fire in replica mode only.

ALTER TABLE ... ENABLE ALWAYS TRIGGER ... - trigger will fire always (obviously)

How to add browse file button to Windows Form using C#

These links explain it with examples

http://dotnetperls.com/openfiledialog

http://www.geekpedia.com/tutorial67_Using-OpenFileDialog-to-open-files.html

private void button1_Click(object sender, EventArgs e)
{
    int size = -1;
    DialogResult result = openFileDialog1.ShowDialog(); // Show the dialog.
    if (result == DialogResult.OK) // Test result.
    {
       string file = openFileDialog1.FileName;
       try
       {
          string text = File.ReadAllText(file);
          size = text.Length;
       }
       catch (IOException)
       {
       }
    }
    Console.WriteLine(size); // <-- Shows file size in debugging mode.
    Console.WriteLine(result); // <-- For debugging use.
}

$(form).ajaxSubmit is not a function

$(form).ajaxSubmit(); 

triggers another validation resulting to a recursion. try changing it to

form.ajaxSubmit();