Programs & Examples On #Ora 03113

ORA-03113: end-of-file on communication channel

ORA-03113: end-of-file on communication channel after long inactivity in ASP.Net app

ORA-03113: end-of-file on communication channel

Is the database letting you know that the network connection is no more. This could be because:

  1. A network issue - faulty connection, or firewall issue
  2. The server process on the database that is servicing you died unexpectedly.

For 1) (firewall) search tahiti.oracle.com for SQLNET.EXPIRE_TIME. This is a sqlnet.ora parameter that will regularly send a network packet at a configurable interval ie: setting this will make the firewall believe that the connection is live.

For 1) (network) speak to your network admin (connection could be unreliable)

For 2) Check the alert.log for errors. If the server process failed there will be an error message. Also a trace file will have been written to enable support to identify the issue. The error message will reference the trace file.

Support issues can be raised at metalink.oracle.com with a suitable Customer Service Identifier (CSI)

How can I schedule a job to run a SQL query daily?

Using T-SQL: My job is executing stored procedure. You can easy change @command to run your sql.

EXEC msdb.dbo.sp_add_job  
   @job_name = N'MakeDailyJob',   
   @enabled = 1,   
   @description = N'Procedure execution every day' ; 

 EXEC msdb.dbo.sp_add_jobstep  
    @job_name = N'MakeDailyJob',   
    @step_name = N'Run Procedure',   
    @subsystem = N'TSQL',   
    @command = 'exec BackupFromConfig';

 EXEC msdb.dbo.sp_add_schedule  
    @schedule_name = N'Everyday schedule',   
    @freq_type = 4,  -- daily start
    @freq_interval = 1,
    @active_start_time = '230000' ;   -- start time 23:00:00

 EXEC msdb.dbo.sp_attach_schedule  
   @job_name = N'MakeDailyJob',  
   @schedule_name = N'Everyday schedule' ;

 EXEC msdb.dbo.sp_add_jobserver  
   @job_name = N'MakeDailyJob',  
   @server_name = @@servername ;

Google Chrome form autofill and its yellow background

Adding autocomplete="off" is not gonna cut it.

Change input type attribute to type="search".
Google doesn't apply auto-fill to inputs with a type of search.

Hope this saves you some time.

How to resolve "local edit, incoming delete upon update" message

This issue often happens when we try to merge another branch changes from a wrong directory.

Ex:

Branch2\Branch1_SubDir$ svn merge -rStart:End Branch1
         ^^^^^^^^^^^^
   Merging at wrong location

A conflict that gets thrown on its execution is :

Tree conflict on 'Branch1_SubDir'
   > local missing or deleted or moved away, incoming dir edit upon merge

And when you select q to quit resolution, you get status as:

 M      .
!     C Branch1_SubDir
      >   local missing or deleted or moved away, incoming dir edit upon merge
!     C Branch1_AnotherSubDir
      >   local missing or deleted or moved away, incoming dir edit upon merge

which clearly means that the merge contains changes related to Branch1_SubDir and Branch1_AnotherSubDir, and these folders couldn't be found inside Branch1_SubDir(obviously a directory can't be inside itself).

How to avoid this issue at first place:

Branch2$ svn merge -rStart:End Branch1
 ^^^^
Merging at root location

The simplest fix for this issue that worked for me :

svn revert -R .

Encrypt and decrypt a string in C#?

I have an open source project called X509Crypto that leverages certificates to encrypt and decrypt strings. It's very easy to use. Here is an example for how to use it:

1. Use the X509Crypto Commandline Interface (CLI) to generate a new encryption certificate and key pair

>x509crypto.exe
X509Crypto> makecert -context user -keysize medium -alias myvault

Certificate with thumbprint B31FE7E7AE5229F8186782742CF579197FA859FD was added to X509Alias "myvault" in the user X509Context

X509Crypto>

2. Use the Encrypt CLI command to add a secret to your new X509Alias

X509Crypto> encrypt -text -alias myvault -context user -secret apikey -in "80EAF03248965AC2B78090"

Secret apikey has been added to X509Alias myvault in the user X509Context

X509Crypto>

3. Reference the secret in your program

Once you have an X509Alias established with your secret(s) added, it is trivial to retreive them in your program with the Org.X509Crypto nuget package installed:

using Org.X509Crypto;

namespace SampleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            var Alias = new X509Alias(@"myvault", X509Context.UserReadOnly);
            var apiKey = Alias.RecoverSecret(@"apikey");
        }
    }
}

How to clear form after submit in Angular 2?

To angular version 4, you can use this:

this.heroForm.reset();

But, you could need a initial value like:

ngOnChanges() {
 this.heroForm.reset({
  name: this.hero.name, //Or '' to empty initial value. 
  address: this.hero.addresses[0] || new Address()
 });
}

It is important to resolve null problem in your object reference.

reference link, Search for "reset the form flags".

How do I detect whether 32-bit Java is installed on x64 Windows, only looking at the filesystem and registry?

This seems to provide the info on Windows:

1.) Open a windows command prompt.

2.) Key in: java -XshowSettings:all and hit ENTER.

3.) A lot of information will be displayed on the command window. Scroll up until you find the string: sun.arch.data.model.

4.) If it says sun.arch.data.model = 32, your VM is 32 bit. If it says sun.arch.data.model = 64, your VM is 64 bit.

Is div inside list allowed?

Yes it is valid according to xhtml1-strict.dtd. The following XHTML passes the validation:

<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>Test</title>
</head>
<body>
<ul>
  <li><div>test</div></li>
</ul>
</body>
</html>

Is it possible to wait until all javascript files are loaded before executing javascript code?

Thats work for me:

var jsScripts = [];

jsScripts.push("/js/script1.js" );
jsScripts.push("/js/script2.js" );
jsScripts.push("/js/script3.js" );

$(jsScripts).each(function( index, value ) {
    $.holdReady( true );
    $.getScript( value ).done(function(script, status) {
        console.log('Loaded ' + index + ' : ' + value + ' (' + status + ')');                
        $.holdReady( false );
    });
});

How do you remove a specific revision in the git history?

Answers of rado and kareem do nothing for me (only message "Current branch is up to date." appears). Possibly this happens because '^' symbol doesn't work in Windows console. However, according to this comment, replacing '^' by '~1' solves the problem.

git rebase --onto <commit-id>^ <commit-id>

"Connect failed: Access denied for user 'root'@'localhost' (using password: YES)" from php function

Is there a user account entry in the DB for root@localhost? In MySQL you can set different user account permissions by host. There could be several different accounts with the same name combined with the host they are connecting from. The most common are [email protected] and root@localhost. These can have different passwords and permissions. Make sure root@localhost exist and has the settings you expect.

I am willing to bet, based on your explanation, that this is the problem. Connecting from another PC uses a different account than root@localhost and the command line I think connects using [email protected].

How to set the font size in Emacs?

(set-face-attribute 'default nil :height 100)

The value is in 1/10pt, so 100 will give you 10pt, etc.

Sum rows in data.frame or matrix

The rowSums function (as Greg mentions) will do what you want, but you are mixing subsetting techniques in your answer, do not use "$" when using "[]", your code should look something more like:

data$new <- rowSums( data[,43:167] )

If you want to use a function other than sum, then look at ?apply for applying general functions accross rows or columns.

Change Twitter Bootstrap Tooltip content on click

I only tested this in bootstrap 4 & w/o calling .show()

el.tooltip('hide').attr('data-original-title', 'message');

How to set space between listView Items in Android

Although the solution by Nik Reiman DOES work, I found it not to be an optimal solution for what I wanted to do. Using the divider to set the margins had the problem that the divider will no longer be visible so you can not use it to show a clear boundary between your items. Also, it does not add more "clickable area" to each item thus if you want to make your items clickable and your items are thin, it will be very hard for anyone to click on an item as the height added by the divider is not part of an item.

Fortunately I found a better solution that allows you to both show dividers and allows you to adjust the height of each item using not margins but padding. Here is an example:

ListView

<ListView
android:id="@+id/listView"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>

ListItem

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="10dp"
    android:paddingTop="10dp" >

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:text="Item"
        android:textAppearance="?android:attr/textAppearanceSmall" />

</RelativeLayout>

How to make a HTTP request using Ruby on Rails?

You can use Ruby's Net::HTTP class:

require 'net/http'

url = URI.parse('http://www.example.com/index.html')
req = Net::HTTP::Get.new(url.to_s)
res = Net::HTTP.start(url.host, url.port) {|http|
  http.request(req)
}
puts res.body

vuetify center items into v-flex

wrap button inside <div class="text-xs-center">

<div class="text-xs-center">
  <v-btn primary>
    Signup
  </v-btn>
</div>

Dev uses it in his examples.


For centering buttons in v-card-actions we can add class="justify-center" (note in v2 class is text-center (so without xs):

<v-card-actions class="justify-center">
  <v-btn>
    Signup
  </v-btn>
</v-card-actions>

Codepen


For more examples with regards to centering see here

Compile throws a "User-defined type not defined" error but does not go to the offending line of code

Late Binding

This error can occur due to a missing reference. For example when changing from early binding to late binding, by eliminating the reference, some code may remain that references data types specific the the dropped reference.

Try including the reference to see if the problem disappears.

Maybe the error is not a compiler error but a linker error, so the specific line is unknown. Shame on Microsoft!

SQL Greater than, Equal to AND Less Than

If start time is a datetime type then you can use something like

SELECT BookingId, StartTime
FROM Booking
WHERE StartTime >= '2012-03-08 00:00:00.000' 
AND StartTime <= '2012-03-08 01:00:00.000'

Obviously you would want to use your own values for the times but this should give you everything in that 1 hour period inclusive of both the upper and lower limit.

You can use the GETDATE() function to get todays current date.

What is the difference between single-quoted and double-quoted strings in PHP?

Some might say that I'm a little off-topic, but here it is anyway:

You don't necessarily have to choose because of your string's content between:
echo "It's \"game\" time."; or echo 'It\'s "game" time.';

If you're familiar with the use of the english quotation marks, and the correct character for the apostrophe, you can use either double or single quotes, because it won't matter anymore:
echo "It’s “game” time."; and echo 'It’s “game” time.';

Of course you can also add variables if needed. Just don't forget that they get evaluated only when in double quotes!

Undoing accidental git stash pop

From git stash --help

Recovering stashes that were cleared/dropped erroneously
   If you mistakenly drop or clear stashes, they cannot be recovered through the normal safety mechanisms. However, you can try the
   following incantation to get a list of stashes that are still in your repository, but not reachable any more:

       git fsck --unreachable |
       grep commit | cut -d\  -f3 |
       xargs git log --merges --no-walk --grep=WIP

This helped me better than the accepted answer with the same scenario.

How to remove illegal characters from path and filenames?

I absolutely prefer the idea of Jeff Yates. It will work perfectly, if you slightly modify it:

string regex = String.Format("[{0}]", Regex.Escape(new string(Path.GetInvalidFileNameChars())));
Regex removeInvalidChars = new Regex(regex, RegexOptions.Singleline | RegexOptions.Compiled | RegexOptions.CultureInvariant);

The improvement is just to escape the automaticially generated regex.

Selecting Multiple Values from a Dropdown List in Google Spreadsheet

You would use data validation for this. Click in the cell you want to have a multiple drop down > DATA > Validation > Criteria (List from a Range) - here you select form a list of items you want in the drop down. And .. you are good. I have included an example to reference.

How to create an empty DataFrame with a specified schema?

This is helpful for testing purposes.

Seq.empty[String].toDF()

Custom exception type

From WebReference:

throw { 
  name:        "System Error", 
  level:       "Show Stopper", 
  message:     "Error detected. Please contact the system administrator.", 
  htmlMessage: "Error detected. Please contact the <a href=\"mailto:[email protected]\">system administrator</a>.",
  toString:    function(){return this.name + ": " + this.message;} 
}; 

Passing multiple argument through CommandArgument of Button in Asp.net

A little more elegant way of doing the same adding on to the above comment ..

<asp:GridView ID="grdParent" runat="server" BackColor="White" BorderColor="#DEDFDE"
                           AutoGenerateColumns="false"
                            OnRowDeleting="deleteRow"
                         GridLines="Vertical">
      <asp:BoundField DataField="IdTemplate" HeaderText="IdTemplate" />
      <asp:BoundField DataField="EntityId" HeaderText="EntityId"  />
    <asp:TemplateField ShowHeader="false">
        <ItemTemplate>
           <asp:LinkButton ID="lnkCustomize" Text="Delete"  CommandName="Delete"  CommandArgument='<%#Eval("IdTemplate") + ";" +Eval("EntityId")%>'  runat="server"> 
           </asp:LinkButton>   
        </ItemTemplate>   
    </asp:TemplateField>
     </asp:GridView>

And on the server side:

protected void deleteRow(object sender, GridViewDeleteEventArgs e)
{
    string IdTemplate= e.Values["IdTemplate"].ToString();
    string EntityId = e.Values["EntityId"].ToString();

   // Do stuff..
}

Generate random numbers uniformly over an entire range

Why rand is a bad idea

Most of the answers you got here make use of the rand function and the modulus operator. That method may not generate numbers uniformly (it depends on the range and the value of RAND_MAX), and is therefore discouraged.

C++11 and generation over a range

With C++11 multiple other options have risen. One of which fits your requirements, for generating a random number in a range, pretty nicely: std::uniform_int_distribution. Here's an example:

const int range_from  = 0;
const int range_to    = 10;
std::random_device                  rand_dev;
std::mt19937                        generator(rand_dev());
std::uniform_int_distribution<int>  distr(range_from, range_to);

std::cout << distr(generator) << '\n';

And here's the running example.

Template function may help some:

template<typename T>
T random(T range_from, T range_to) {
    std::random_device                  rand_dev;
    std::mt19937                        generator(rand_dev());
    std::uniform_int_distribution<T>    distr(range_from, range_to);
    return distr(generator);
}

Other random generators

The <random> header offers innumerable other random number generators with different kind of distributions including Bernoulli, Poisson and normal.

How can I shuffle a container?

The standard provides std::shuffle, which can be used as follows:

std::vector<int> vec = {4, 8, 15, 16, 23, 42};

std::random_device random_dev;
std::mt19937       generator(random_dev());

std::shuffle(vec.begin(), vec.end(), generator);

The algorithm will reorder the elements randomly, with a linear complexity.

Boost.Random

Another alternative, in case you don't have access to a C++11+ compiler, is to use Boost.Random. Its interface is very similar to the C++11 one.

How to remove duplicate objects in a List<MyObject> without equals/hashcode?

  1. override hashCode() and equals(..) using those 4 fields
  2. use new HashSet<Blog>(blogList) - this will give you a Set which has no duplicates by definition

Update: Since you can't change the class, here's an O(n^2) solution:

  • create a new list
  • iterate the first list
  • in an inner loop iterate the second list and verify if it has an element with the same fields

You can make this more efficient if you provide a HashSet data structure with externalized hashCode() and equals(..) methods.

How to Resize image in Swift?

UIImage Extension Swift 5

extension UIImage {
    func resize(_ width: CGFloat, _ height:CGFloat) -> UIImage? {
        let widthRatio  = width / size.width
        let heightRatio = height / size.height
        let ratio = widthRatio > heightRatio ? heightRatio : widthRatio
        let newSize = CGSize(width: size.width * ratio, height: size.height * ratio)
        let rect = CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height)
        UIGraphicsBeginImageContextWithOptions(newSize, false, 1.0)
        self.draw(in: rect)
        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return newImage
    }
}


Use : UIImage().resize(200, 300)

`export const` vs. `export default` in ES6

From the documentation:

Named exports are useful to export several values. During the import, one will be able to use the same name to refer to the corresponding value.

Concerning the default export, there is only a single default export per module. A default export can be a function, a class, an object or anything else. This value is to be considered as the "main" exported value since it will be the simplest to import.

Center text in div?

You may try to use in your CSS the property vertical-align in order to center it verticaly

div {  
    vertical-align:middle;  
}

if it's a size problem, please notice that 2 text lines and a padding style have great chance to have a height superior to 30px.

For example, if your font size is 12 px and your div padding is 5 px, a one text line div height will be 5px (padding-top) + 12px + 5 px (padding-bottom) = 22px < 30px so no problem,

With a 2 text lines div, it will be 5px +12px *2 (2 lines) + 5px = 34px > 30px and your div height will be automatically changed.

Try either to increase your div height (maybe 40px) or to reduce your padding.

Hope it will help

Counting the number of occurences of characters in a string

I don't want to give out the full code. So I want to give you the challenge and have fun with it. I encourage you to make the code simpler and with only 1 loop.

Basically, my idea is to pair up the characters comparison, side by side. For example, compare char 1 with char 2, char 2 with char 3, and so on. When char N not the same with char (N+1) then reset the character count. You can do this in one loop only! While processing this, form a new string. Don't use the same string as your input. That's confusing.

Remember, making things simple counts. Life for developers is hard enough looking at complex code.

Have fun!

Tommy "I should be a Teacher" Kwee

Detect the Internet connection is offline?

You can use $.ajax()'s error callback, which fires if the request fails. If textStatus equals the string "timeout" it probably means connection is broken:

function (XMLHttpRequest, textStatus, errorThrown) {
  // typically only one of textStatus or errorThrown 
  // will have info
  this; // the options for this ajax request
}

From the doc:

Error: A function to be called if the request fails. The function is passed three arguments: The XMLHttpRequest object, a string describing the type of error that occurred and an optional exception object, if one occurred. Possible values for the second argument (besides null) are "timeout", "error", "notmodified" and "parsererror". This is an Ajax Event

So for example:

 $.ajax({
   type: "GET",
   url: "keepalive.php",
   success: function(msg){
     alert("Connection active!")
   },
   error: function(XMLHttpRequest, textStatus, errorThrown) {
       if(textStatus == 'timeout') {
           alert('Connection seems dead!');
       }
   }
 });

Compare two Byte Arrays? (Java)

You can use both Arrays.equals() and MessageDigest.isEqual(). These two methods have some differences though.

MessageDigest.isEqual() is a time-constant comparison method and Arrays.equals() is non time-constant and it may bring some security issues if you use it in a security application.

The details for the difference can be read at Arrays.equals() vs MessageDigest.isEqual()

FtpWebRequest Download File

This paragraph from the FptWebRequest class reference might be of interest to you:

The URI may be relative or absolute. If the URI is of the form "ftp://contoso.com/%2fpath" (%2f is an escaped '/'), then the URI is absolute, and the current directory is /path. If, however, the URI is of the form "ftp://contoso.com/path", first the .NET Framework logs into the FTP server (using the user name and password set by the Credentials property), then the current directory is set to /path.

Setting environment variables in Linux using Bash

export VAR=value will set VAR to value. Enclose it in single quotes if you want spaces, like export VAR='my val'. If you want the variable to be interpolated, use double quotes, like export VAR="$MY_OTHER_VAR".

select dept names who have more than 2 employees whose salary is greater than 1000

select deptname from dept_1
where exists
(
SELECT DeptId,COUNT(*)        
FROM emp_1  
where salary>1000
and emp_1.deptid=dept_1.deptid   
GROUP BY DeptId 
having count(*)>2)

Codeigniter - no input file specified

My site is hosted on MochaHost, i had a tough time to setup the .htaccess file so that i can remove the index.php from my urls. However, after some googling, i combined the answer on this thread and other answers. My final working .htaccess file has the following contents:

<IfModule mod_rewrite.c>
    # Turn on URL rewriting
    RewriteEngine On

    # If your website begins from a folder e.g localhost/my_project then 
    # you have to change it to: RewriteBase /my_project/
    # If your site begins from the root e.g. example.local/ then
    # let it as it is
    RewriteBase /

    # Protect application and system files from being viewed when the index.php is missing
    RewriteCond $1 ^(application|system|private|logs)

    # Rewrite to index.php/access_denied/URL
    RewriteRule ^(.*)$ index.php/access_denied/$1 [PT,L]

    # Allow these directories and files to be displayed directly:
    RewriteCond $1 ^(index\.php|robots\.txt|favicon\.ico|public|app_upload|assets|css|js|images)

    # No rewriting
    RewriteRule ^(.*)$ - [PT,L]

    # Rewrite to index.php/URL
    RewriteRule ^(.*)$ index.php?/$1 [PT,L]
</IfModule>

How to validate GUID is a GUID

Use GUID constructor standard functionality

Public Function IsValid(pString As String) As Boolean

    Try
        Dim mGuid As New Guid(pString)
    Catch ex As Exception
        Return False
    End Try
    Return True

End Function

Calculating time difference in Milliseconds

I do not know how does your PersonalizationGeoLocationServiceClientHelper works. Probably it performs some sort of caching, so requests for the same IP address may return extremely fast.

How to fix Hibernate LazyInitializationException: failed to lazily initialize a collection of roles, could not initialize proxy - no Session

For those using JaVers, given an audited entity class, you may want to ignore the properties causing the LazyInitializationException exception (e.g. by using the @DiffIgnore annotation).

This tells the framework to ignore those properties when calculating the object differences, so it won't try to read from the DB the related objects outside the transaction scope (thus causing the exception).

Angular 2: 404 error occur when I refresh through the browser

If you're running Angular 2 through ASP.NET Core 1 in Visual Studio 2015, you might find this solution from Jürgen Gutsch helpful. He describes it in a blog post. It was the best solution for me. Place the C# code provided below in your Startup.cs public void Configure() just before app.UseStaticFiles();

app.Use( async ( context, next ) => {
    await next();

    if( context.Response.StatusCode == 404 && !Path.HasExtension( context.Request.Path.Value ) ) {
        context.Request.Path = "/index.html";
        await next();
    }
});

Copy text from nano editor to shell

The copy buffer can't be accessed outside of nano, and nowhere I found any buffer file to read.

Here is a dirty alternative when in full NOX: Printing a given file line in the bash history.

So the given line is available as a command with the UP key.

sed "LINEq;d" FILENAME >> ~/.bash_history

Example:

sed "342q;d" doc.txt >> ~/.bash_history

Then to reload the history into the current session:

history -n

Or to make history reloading automatic at new prompts, paste this in .bash_profile:

PROMPT_COMMAND='history -n ; $PROMPT_COMMAND'

Note for AZERTY keyboards and very probably others layouts that require SHIFT for printing numbers from the top keys.

To toggle nano text selection (Mark Set/Unset) the shortcut is:

CTRL + SHIFT + 2

Or

ALT + a

You can then select the text with the arrows keys.

All of the others shortcuts works fine as the documentation:

CTRL + k or F9 to cut.

CTRL + u or F10 to paste.

reactjs giving error Uncaught TypeError: Super expression must either be null or a function, not undefined

I had this problem because my react and react-dom versions were not matching after a merge.

I fixed it by manually entering the version number I wanted and re-running npm install.

How to download a file with Node.js (without using third-party libraries)?

Based on the other answers above and some subtle issues, here is my attempt.

  1. Only create the fs.createWriteStream if you get a 200 OK status code. This reduces the amount of fs.unlink commands required to tidy up temporary file handles.
  2. Even on a 200 OK we can still possibly reject due to an EEXIST file already exists.
  3. Recursively call download if you get a 301 Moved Permanently or 302 Found (Moved Temporarily) redirect following the link location provided in the header.
  4. The issue with some of the other answers recursively calling download was that they called resolve(download) instead of download(...).then(() => resolve()) so the Promise would return before the download actually finished. This way the nested chain of promises resolve in the correct order.
  5. It might seem cool to clean up the temp file asynchronously, but I chose to reject only after that completed too so I know that everything start to finish is done when this promise resolves or rejects.
const https = require('https');
const fs = require('fs');

/**
 * Download a resource from `url` to `dest`.
 * @param {string} url - Valid URL to attempt download of resource
 * @param {string} dest - Valid path to save the file.
 * @returns {Promise<void>} - Returns asynchronously when successfully completed download
 */
function download(url, dest) {
  return new Promise((resolve, reject) => {
    const request = https.get(url, response => {
      if (response.statusCode === 200) {
 
        const file = fs.createWriteStream(dest, { flags: 'wx' });
        file.on('finish', () => resolve());
        file.on('error', err => {
          file.close();
          if (err.code === 'EEXIST') reject('File already exists');
          else fs.unlink(dest, () => reject(err.message)); // Delete temp file
        });
        response.pipe(file);
      } else if (response.statusCode === 302 || response.statusCode === 301) {
        //Recursively follow redirects, only a 200 will resolve.
        download(response.headers.location, dest).then(() => resolve());
      } else {
        reject(`Server responded with ${response.statusCode}: ${response.statusMessage}`);
      }
    });

    request.on('error', err => {
      reject(err.message);
    });
  });
}

Plotting images side by side using matplotlib

If the images are in an array and you want to iterate through each element and print it, you can write the code as follows:

plt.figure(figsize=(10,10)) # specifying the overall grid size

for i in range(25):
    plt.subplot(5,5,i+1)    # the number of images in the grid is 5*5 (25)
    plt.imshow(the_array[i])

plt.show()

Also note that I used subplot and not subplots. They're both different

Refresh (reload) a page once using jQuery?

For refreshing page with javascript, you can simply use:

location.reload();

How do I get Bin Path?

var path = Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().GetName().CodeBase)?.Replace("file:\\", "");

Convert int to a bit array in .NET

int value = 3;

var array = Convert.ToString(value, 2).PadLeft(8, '0').ToArray();

How to get "their" changes in the middle of conflicting Git rebase?

You want to use:

git checkout --ours foo/bar.java
git add foo/bar.java

If you rebase a branch feature_x against main (i.e. running git rebase main while on branch feature_x), during rebasing ours refers to main and theirs to feature_x.

As pointed out in the git-rebase docs:

Note that a rebase merge works by replaying each commit from the working branch on top of the branch. Because of this, when a merge conflict happens, the side reported as ours is the so-far rebased series, starting with <upstream>, and theirs is the working branch. In other words, the sides are swapped.

For further details read this thread.

Error message "Unable to install or run the application. The application requires stdole Version 7.0.3300.0 in the GAC"

Interesting, I didn't have any references to stdole in my project, but I had a user still receiving the error. I had to add the reference, then change the setting to include. Hopefully that will work.

An existing connection was forcibly closed by the remote host - WCF

I just had this error now in server only and the solution was to set a maxItemsInObjectGraph attribute in wcf web.config under <behavior> tag:

<dataContractSerializer maxItemsInObjectGraph="2147483646"/>

Passing route control with optional parameter after root in express?

That would work depending on what client.get does when passed undefined as its first parameter.

Something like this would be safer:

app.get('/:key?', function(req, res, next) {
    var key = req.params.key;
    if (!key) {
        next();
        return;
    }
    client.get(key, function(err, reply) {
        if(client.get(reply)) {
            res.redirect(reply);
        }
        else {
            res.render('index', {
                link: null
            });
        }
    });
});

There's no problem in calling next() inside the callback.

According to this, handlers are invoked in the order that they are added, so as long as your next route is app.get('/', ...) it will be called if there is no key.

What is the difference between RTP or RTSP in a streaming server?

You are getting something wrong... RTSP is a realtime streaming protocol. Meaning, you can stream whatever you want in real time. So you can use it to stream LIVE content (no matter what it is, video, audio, text, presentation...). RTP is a transport protocol which is used to transport media data which is negotiated over RTSP.

You use RTSP to control media transmission over RTP. You use it to setup, play, pause, teardown the stream...

So, if you want your server to just start streaming when the URL is requested, you can implement some sort of RTP-only server. But if you want more control and if you are streaming live video, you must use RTSP, because it transmits SDP and other important decoding data.

Read the documents I linked here, they are a good starting point.

How to save an HTML5 Canvas as an image on a server?

If you want to save data that is derived from a Javascript canvas.toDataURL() function, you have to convert blanks into plusses. If you do not do that, the decoded data is corrupted:

<?php
  $encodedData = str_replace(' ','+',$encodedData);
  $decocedData = base64_decode($encodedData);
?>

http://php.net/manual/ro/function.base64-decode.php

How can I convert a .jar to an .exe?

JSmooth .exe wrapper

JSmooth is a Java Executable Wrapper. It creates native Windows launchers (standard .exe) for your Java applications. It makes java deployment much smoother and user-friendly, as it is able to find any installed Java VM by itself. When no VM is available, the wrapper can automatically download and install a suitable JVM, or simply display a message or redirect the user to a website.

JSmooth provides a variety of wrappers for your java application, each of them having their own behavior: Choose your flavor!

Download: http://jsmooth.sourceforge.net/

JarToExe 1.8 Jar2Exe is a tool to convert jar files into exe files. Following are the main features as describe on their website:

Can generate “Console”, “Windows GUI”, “Windows Service” three types of .exe files.

Generated .exe files can add program icons and version information. Generated .exe files can encrypt and protect java programs, no temporary files will be generated when the program runs.

Generated .exe files provide system tray icon support. Generated .exe files provide record system event log support. Generated windows service .exe files are able to install/uninstall itself, and support service pause/continue.

Executor

Package your Java application as a jar, and Executor will turn the jar into a Windows .exe file, indistinguishable from a native application. Simply double-clicking the .exe file will invoke the Java Runtime Environment and launch your application.

Command failed due to signal: Segmentation fault: 11

In my case Product Clean and then restarting Xcode did resolve this problem...

Why XML-Serializable class need a parameterless constructor

This is a limitation of XmlSerializer. Note that BinaryFormatter and DataContractSerializer do not require this - they can create an uninitialized object out of the ether and initialize it during deserialization.

Since you are using xml, you might consider using DataContractSerializer and marking your class with [DataContract]/[DataMember], but note that this changes the schema (for example, there is no equivalent of [XmlAttribute] - everything becomes elements).

Update: if you really want to know, BinaryFormatter et al use FormatterServices.GetUninitializedObject() to create the object without invoking the constructor. Probably dangerous; I don't recommend using it too often ;-p See also the remarks on MSDN:

Because the new instance of the object is initialized to zero and no constructors are run, the object might not represent a state that is regarded as valid by that object. The current method should only be used for deserialization when the user intends to immediately populate all fields. It does not create an uninitialized string, since creating an empty instance of an immutable type serves no purpose.

I have my own serialization engine, but I don't intend making it use FormatterServices; I quite like knowing that a constructor (any constructor) has actually executed.

Grouping into interval of 5 minutes within a time range

For postgres, I found it easier and more accurate to use the

date_trunc

function, like:

select name, sum(count), date_trunc('minute',timestamp) as timestamp
FROM table
WHERE xxx
GROUP BY name,date_trunc('minute',timestamp)
ORDER BY timestamp

You can provide various resolutions like 'minute','hour','day' etc... to date_trunc.

Selenium Webdriver move mouse to Point

I am using JavaScript but some of the principles are common I am sure.

The code I am using is as follows:

    var s = new webdriver.ActionSequence(d);
    d.findElement(By.className('fc-time')).then(function(result){
        s.mouseMove(result,l).click().perform();
    });

the driver = d. The location = l is simply {x:300,y:500) - it is just an offset.

What I found during my testing was that I could not make it work without using the method to find an existing element first, using that at a basis from where to locate my click.

I suspect the figures in the locate are a bit more difficult to predict than I thought.

It is an old post but this response may help other newcomers like me.

Create JSON object dynamically via JavaScript (Without concate strings)

This topic, especially the answer of Xotic750 was very helpful to me. I wanted to generate a json variable to pass it to a php script using ajax. My values were stored into two arrays, and i wanted them in json format. This is a generic example:

valArray1 = [121, 324, 42, 31];
valArray2 = [232, 131, 443];
myJson = {objArray1: {}, objArray2: {}};
for (var k = 1; k < valArray1.length; k++) {
    var objName = 'obj' + k;
    var objValue = valArray1[k];
    myJson.objArray1[objName] = objValue;
}
for (var k = 1; k < valArray2.length; k++) {
    var objName = 'obj' + k;
    var objValue = valArray2[k];
    myJson.objArray2[objName] = objValue;
}
console.log(JSON.stringify(myJson));

The result in the console Log should be something like this:

{
   "objArray1": {
        "obj1": 121,
        "obj2": 324,
        "obj3": 42,
        "obj4": 31
   },
   "objArray2": {
        "obj1": 232,
        "obj2": 131,
        "obj3": 443
  }
}

How to hide collapsible Bootstrap 4 navbar on click

The easiest way to do it using only Angular 2/4 template with no coding:

<nav class="navbar navbar-default" aria-expanded="false">
  <div class="container-wrapper">

    <div class="navbar-header">
      <button type="button" class="navbar-toggle collapsed" (click)="isCollapsed = !isCollapsed">
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>
    </div>

    <div class="navbar-collapse collapse no-transition" [attr.aria-expanded]="!isCollapsed" [ngClass]="{collapse: isCollapsed}">
      <ul class="nav navbar-nav" (click)="isCollapsed = !isCollapsed">
        <li [routerLinkActive]="['active']" [routerLinkActiveOptions]="{exact: true}"><a routerLink="/">Home</a></li>
        <li [routerLinkActive]="['active']"><a routerLink="/about">About</a></li>
        <li [routerLinkActive]="['active']"><a routerLink="/portfolio">Portfolio</a></li>
        <li [routerLinkActive]="['active']"><a routerLink="/contacts">Contacts</a></li>
      </ul>
    </div>

  </div>
</nav>

Python 3 ImportError: No module named 'ConfigParser'

I was having the same problem. Turns out, I needed to install python3 devel on my centos. First, you need to search for the package that is compatible with your system.

yum search python3 | grep devel

Then, install the package as:

yum install -y python3-devel.x86_64

Then, install mysqlclient from pip

pip install mysqlclient

Padding or margin value in pixels as integer using jQuery

This simple function will do it:

$.fn.pixels = function(property) {
    return parseInt(this.css(property).slice(0,-2));
};

Usage:

var padding = $('#myId').pixels('paddingTop');

How to save a base64 image to user's disk using JavaScript?

HTML5 download attribute

Just to allow user to download the image or other file you may use the HTML5 download attribute.

Static file download

<a href="/images/image-name.jpg" download>
<!-- OR -->
<a href="/images/image-name.jpg" download="new-image-name.jpg"> 

Dynamic file download

In cases requesting image dynamically it is possible to emulate such download.

If your image is already loaded and you have the base64 source then:

function saveBase64AsFile(base64, fileName) {
    var link = document.createElement("a");

    document.body.appendChild(link); // for Firefox

    link.setAttribute("href", base64);
    link.setAttribute("download", fileName);
    link.click();
}

Otherwise if image file is downloaded as Blob you can use FileReader to convert it to Base64:

function saveBlobAsFile(blob, fileName) {
    var reader = new FileReader();

    reader.onloadend = function () {    
        var base64 = reader.result ;
        var link = document.createElement("a");

        document.body.appendChild(link); // for Firefox

        link.setAttribute("href", base64);
        link.setAttribute("download", fileName);
        link.click();
    };

    reader.readAsDataURL(blob);
}

Firefox

The anchor tag you are creating also needs to be added to the DOM in Firefox, in order to be recognized for click events (Link).

IE is not supported: Caniuse link

mysqldump data only

Best to dump to a compressed file

mysqldump --no-create-info -u username -hhostname -p dbname | gzip > /backupsql.gz

and to restore using pv apt-get install pv to monitor progress

pv backupsql.gz | gunzip | mysql -uusername -hhostip -p dbname

Combining multiple commits before pushing in Git

And my way of squashing multiple push is (perhaps you pushed to your own branch many commits and now you wish to do a pull request and you don't want to clutter them with many commits which you have already pushed). The way I do that (no other simpler option as far as I can tell is).

  1. Create new branch for the sake of squash (branch from the original branch you wish to pull request to).
  2. Push the newly created branch.
  3. Merge branch with commits (already pushed) to new branch.
  4. Rebase new branch and squash.
  5. Push new branch.
  6. Create new pull request for new branch which now has single commit.

Example:

git checkout from_branch_you_wish_to_pull_request_to
git checkout -b new_branch_will_have_single_squashed_commit
git push -u new_branch_will_have_single_squashed_commit
git merge older_branch_with_all_those_multiple_commits
git rebase -i (here you squash)
git push origin new_branch_will_have_single_squashed_commit

You can now pull request into from_branch_you_wish_to_pull_request_to

Send inline image in email

An even more minimalistic example:

var linkedResource = new LinkedResource(@"C:\Image.jpg", MediaTypeNames.Image.Jpeg);

// My mail provider would not accept an email with only an image, adding hello so that the content looks less suspicious.
var htmlBody = $"hello<img src=\"cid:{linkedResource.ContentId}\"/>";
var alternateView = AlternateView.CreateAlternateViewFromString(htmlBody, null, MediaTypeNames.Text.Html);
alternateView.LinkedResources.Add(linkedResource);

var mailMessage = new MailMessage
{
    From = new MailAddress("[email protected]"),
    To = { "[email protected]" },
    Subject = "yourSubject",
    AlternateViews = { alternateView }
};

var smtpClient = new SmtpClient();
smtpClient.Send(mailMessage);

phpMyAdmin + CentOS 6.0 - Forbidden

I tried all answers provided here: editing phpMyAdmin.conf, changing selinux context for phpmyadmin folder, disabling selinux... but I still got a 'Forbidden' from the web server.

I finally found what I was missing in Edouard Thiel post here :

$ yum install php

then restart httpd :

$ service httpd restart => for centos 6 hots

$ systemctl restart httpd => for centos 7 hosts

What has me amazed is why php is not installed as dependency for phpmyadmin in the first place.

Regards, Fred

Maven version with a property

The version of the pom.xml should be valid

<groupId>com.amazonaws.lambda</groupId>
<artifactId>lambda</artifactId>
<version>2.2.4 SNAPSHOT</version>
<packaging>jar</packaging>

This version should not be like 2.2.4. etc

How can I copy columns from one sheet to another with VBA in Excel?

The following works fine for me in Excel 2007. It is simple, and performs a full copy (retains all formatting, etc.):

Sheets("Sheet1").Columns(1).Copy Destination:=Sheets("Sheet2").Columns(2)

"Columns" returns a Range object, and so this is utilizing the "Range.Copy" method. "Destination" is an option to this method - if not provided the default is to copy to the paste buffer. But when provided, it is an easy way to copy.

As when manually copying items in Excel, the size and geometry of the destination must support the range being copied.

How to use onClick event on react Link component?

You are passing hello() as a string, also hello() means execute hello immediately.

try

onClick={hello}

How to write palindrome in JavaScript

function Palindrome(str) {
  let forwardStr = str.toLowerCase().replace(/[\W_]/g, '');
  let reversedStr = forwardStr.split('').reverse().join();

  return forwardStr === reversedStr;
}
console.log(Palindrome('madam'));

docker error: /var/run/docker.sock: no such file or directory

If you're using CentOS 7, and you've installed Docker via yum, don't forget to run:

$ sudo systemctl start docker
$ sudo systemctl enable docker

This will start the server, as well as re-start it automatically on boot.

Change the bullet color of list

I would recommend you to use background-image instead of default list.

.listStyle {
    list-style: none;
    background: url(image_path.jpg) no-repeat left center;
    padding-left: 30px;
    width: 20px;
    height: 20px;
}

Or, if you don't want to use background-image as bullet, there is an option to do it with pseudo element:

.liststyle{
    list-style: none;
    margin: 0;
    padding: 0;
}
.liststyle:before {
    content: "• ";
    color: red; /* or whatever color you prefer */
    font-size: 20px;/* or whatever the bullet size you prefer */
}

Onclick javascript to make browser go back to previous page?

Works for me everytime

<a href="javascript:history.go(-1)">
    <button type="button">
        Back
    </button>
</a>

What are the most common font-sizes for H1-H6 tags

Headings are normally bold-faced; that has been turned off for this demonstration of size correspondence. MSIE and Opera interpret these sizes the same, but note that Gecko browsers and Chrome interpret Heading 6 as 11 pixels instead of 10 pixels/font size 1, and Heading 3 as 19 pixels instead of 18 pixels/font size 4 (though it's difficult to tell the difference even in a direct comparison and impossible in use). It seems Gecko also limits text to no smaller than 10 pixels.

Spring @Value is not resolving to value from property file

Problem is due to problem in my applicationContext.xml vs spring-servlet.xml - it was scoping issue between the beans.

pedjaradenkovic kindly pointed me to an existing resource: Spring @Value annotation in @Controller class not evaluating to value inside properties file and Spring 3.0.5 doesn't evaluate @Value annotation from properties

Refresh Page C# ASP.NET

You can just do a regular postback to refresh the page if you don't want to redirect. Posting back from any control will run the page lifecycle and refresh the page.

To do it from javascript, you can just call the __doPostBack() function.

Python recursive folder read

If you want a flat list of all paths under a given dir (like find . in the shell):

   files = [ 
       os.path.join(parent, name)
       for (parent, subdirs, files) in os.walk(YOUR_DIRECTORY)
       for name in files + subdirs
   ]

To only include full paths to files under the base dir, leave out + subdirs.

Git - Ignore files during merge

You could start by using git merge --no-commit, and then edit the merge however you like i.e. by unstaging config.xml or any other file, then commit. I suspect you'd want to automate it further after that using hooks, but I think it'd be worth going through manually at least once.

Best way to handle list.index(might-not-exist) in python?

It's been quite some time but it's a core part of the stdlib and has dozens of potential methods so I think it's useful to have some benchmarks for the different suggestions and include the numpy method which can be by far the fastest.

import random
from timeit import timeit
import numpy as np

l = [random.random() for i in range(10**4)]
l[10**4 - 100] = 5

# method 1
def fun1(l:list, x:int, e = -1) -> int:
    return [[i for i,elem in enumerate(l) if elem == x] or [e]][0]

# method 2
def fun2(l:list, x:int, e = -1) -> int:
    for i,elem in enumerate(l):
        if elem == x:
            return i
    else:
        return e

# method 3
def fun3(l:list, x:int, e = -1) -> int:
    try:
        idx = l.index(x)
    except ValueError:
        idx = e
    return idx

# method 4
def fun4(l:list, x:int, e = -1) -> int:
    return l.index(x) if x in l else e

l2 = np.array(l)
# method 5
def fun5(l:list or np.ndarray, x:int, e = -1) -> int:
    res = np.where(np.equal(l, x))
    if res[0].any():
        return res[0][0]
    else:        
        return e


if __name__ == "__main__":
    print("Method 1:")
    print(timeit(stmt = "fun1(l, 5)", number = 1000, globals = globals()))
    print("")
    print("Method 2:")
    print(timeit(stmt = "fun2(l, 5)", number = 1000, globals = globals()))
    print("")
    print("Method 3:")
    print(timeit(stmt = "fun3(l, 5)", number = 1000, globals = globals()))
    print("")
    print("Method 4:")
    print(timeit(stmt = "fun4(l, 5)", number = 1000, globals = globals()))
    print("")
    print("Method 5, numpy given list:")
    print(timeit(stmt = "fun5(l, 5)", number = 1000, globals = globals()))
    print("")
    print("Method 6, numpy given np.ndarray:")
    print(timeit(stmt = "fun5(l2, 5)", number = 1000, globals = globals()))
    print("")

When run as main, this results in the following printout on my machine indicating time in seconds to complete 1000 trials of each function:

Method 1: 0.7502102799990098

Method 2: 0.7291318440002215

Method 3: 0.24142152300009911

Method 4: 0.5253471979995084

Method 5, numpy given list: 0.5045417560013448

Method 6, numpy given np.ndarray: 0.011147511999297421

Of course the question asks specifically about lists so the best solution is to use the try-except method, however the speed improvements (at least 20x here compared to try-except) offered by using the numpy data structures and operators instead of python data structures is significant and if building something on many arrays of data that is performance critical then the author should try to use numpy throughout to take advantage of the superfast C bindings. (CPython interpreter, other interpreter performances may vary)

Btw, the reason Method 5 is much slower than Method 6 is because numpy first has to convert the given list to it's own numpy array, so giving it a list doesn't break it it just doesn't fully utilise the speed possible.

How to get a view table query (code) in SQL Server 2008 Management Studio

right-click the view in the object-explorer, select "script view as...", then "create to" and then "new query editor window"

Undefined function mysql_connect()

(Windows mysql config)

Step 1 : Go To Apache Control Panel > Apache > Config > PHP.ini

Step 2 : Search in Notepad (Ctrl+F) For: ;extension_dir = "" (could be commented with a ;). Replace this line with: extension_dir = "C:\php\ext" (please do not you need to remove the ; on the beginning of the sentence).

Step 3 : Search For: extension=php_mysql.dll and remove the ; in the beginning.

Step 4 : Save and Restart You Apache HTTP Server. (On Windows this usually done via a UI)

That's it :)

If you get errors about missing php_mysql.dll you'll probably need to download this file from either the php.net site or the pecl.php.net. (Please be causius about where you get it from)

More info on PHP: Installation of extensions on Windows - Manual

Web.Config Debug/Release

It is possible using ConfigTransform build target available as a Nuget package - https://www.nuget.org/packages/CodeAssassin.ConfigTransform/

All "web.*.config" transform files will be transformed and output as a series of "web.*.config.transformed" files in the build output directory regardless of the chosen build configuration.

The same applies to "app.*.config" transform files in non-web projects.

and then adding the following target to your *.csproj.

<Target Name="TransformActiveConfiguration" Condition="Exists('$(ProjectDir)/Web.$(Configuration).config')" BeforeTargets="Compile" >
    <TransformXml Source="$(ProjectDir)/Web.Config" Transform="$(ProjectDir)/Web.$(Configuration).config" Destination="$(TargetDir)/Web.config" />
</Target>

Posting an answer as this is the first Stackoverflow post that appears in Google on the subject.

How to use UIScrollView in Storyboard

After hours of trial and error, I've found a very easy way to put contents into scrollviews that are 'offscreen'. Tested with XCode 5 & iOS 7. You can do this almost entirely in Storyboard, using 2 small tricks/workarounds :

  1. Drag a viewcontroller onto your storyboard.
  2. Drag a scrollView on this viewController, for the demo you can leave its size default, covering the entire screen.
  3. Now comes trick 1 : before adding any element to the scrollView, drag in a regular 'view' (This view will be made larger than the screen, and will contain all the sub elements like buttons, labels, ...let's call it the 'enclosing view').
  4. Let this enclosing view's Y size in the size inspector to for example 800.
  5. Drop in a label onto the enclosing view, somewhere at Y position 200, name it 'label 1'.
  6. Trick 2 : make sure the enclosing view is selected (not the scrollView !), and set its Y position to for example -250, so you can add an item that is 'outside' the screen
  7. Drop in a label, somewhere at the bottom of the screen, name it 'label 2'. This label is actually 'off screen'.
  8. Reset the Y position of the enclosing view to 0, you'll no longer see label 2, as it was positioned off screen.

So far for the storyboard work, now you need to add a single line of code to the viewController's 'viewDidLoad' method to set the scrollViews contents so it contains the entire 'enclosing view'. I didn't find a way to do this in Storyboard:

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.scrollView.contentSize = CGSizeMake(320, 800);
}

You can try doing this by adding a contentSize keyPath as a size to the scrollView in the Identity Inspector and setting it to (320, 1000).

I think Apple should make this easier in storyboard, in a TableViewController you can just scroll offscreen in Storyboard (just add 20 cells, and you'll see you can simply scroll), this should be possible with a ScrollViewController too.

Leave menu bar fixed on top when scrolled

Or do this in more dynamic way

$(window).bind('scroll', function () {
    var menu = $('.menu');
    if ($(window).scrollTop() > menu.offset().top) {
        menu.addClass('fixed');
    } else {
        menu.removeClass('fixed');
    }
});

In CSS add class

.fixed {
    position: fixed;
    top: 0;
}

What is inf and nan?

Inf is infinity, it's a "bigger than all the other numbers" number. Try subtracting anything you want from it, it doesn't get any smaller. All numbers are < Inf. -Inf is similar, but smaller than everything.

NaN means not-a-number. If you try to do a computation that just doesn't make sense, you get NaN. Inf - Inf is one such computation. Usually NaN is used to just mean that some data is missing.

How to force link from iframe to be opened in the parent window

Try target="_parent" attribute inside the anchor tag.

Difference between OData and REST web services

UPDATE Warning, this answer is extremely out of date now that OData V4 is available.


I wrote a post on the subject a while ago here.

As Franci said, OData is based on Atom Pub. However, they have layered some functionality on top and unfortunately have ignored some of the REST constraints in the process.

The querying capability of an OData service requires you to construct URIs based on information that is not available, or linked to in the response. It is what REST people call out-of-band information and introduces hidden coupling between the client and server.

The other coupling that is introduced is through the use of EDMX metadata to define the properties contained in the entry content. This metadata can be discovered at a fixed endpoint called $metadata. Again, the client needs to know this in advance, it cannot be discovered.

Unfortunately, Microsoft did not see fit to create media types to describe these key pieces of data, so any OData client has to make a bunch of assumptions about the service that it is talking to and the data it is receiving.

How to copy a dictionary and only edit the copy

>>> dict2 = dict1
# dict2 is bind to the same Dict object which binds to dict1, so if you modify dict2, you will modify the dict1

There are many ways to copy Dict object, I simply use

dict_1 = {
           'a':1,
           'b':2
         }
dict_2 = {}
dict_2.update(dict_1)

Obtain form input fields using jQuery?

Had a similar issue with a slight twist and I thought I'd throw this out. I have a callback function that gets the form so I had a form object already and couldn't easy variants on $('form:input'). Instead I came up with:

    var dataValues = {};
    form.find('input').each(
        function(unusedIndex, child) {
            dataValues[child.name] = child.value;
        });

Its similar but not identical situation, but I found this thread very useful and thought I'd tuck this on the end and hope someone else found it useful.

What is a 'multi-part identifier' and why can't it be bound?

I found that I get these a lot when I try to abbreviate, such as:

Table1 t1, Table2 t2 
where t1.ID = t2.ID

Changing it to:

Table1, Table2 
where Table1.ID = Table2.ID

Makes the query work and not throw the error.

Regex: Check if string contains at least one digit

In Java:

public boolean containsNumber(String string)
{
    return string.matches(".*\\d+.*");
}  

Angular: How to download a file from HttpClient?

It took me a while to implement the other responses, as I'm using Angular 8 (tested up to 10). I ended up with the following code (heavily inspired by Hasan).

Note that for the name to be set, the header Access-Control-Expose-Headers MUST include Content-Disposition. To set this in django RF:

http_response = HttpResponse(package, content_type='application/javascript')
http_response['Content-Disposition'] = 'attachment; filename="{}"'.format(filename)
http_response['Access-Control-Expose-Headers'] = "Content-Disposition"

In angular:

  // component.ts
  // getFileName not necessary, you can just set this as a string if you wish
  getFileName(response: HttpResponse<Blob>) {
    let filename: string;
    try {
      const contentDisposition: string = response.headers.get('content-disposition');
      const r = /(?:filename=")(.+)(?:")/
      filename = r.exec(contentDisposition)[1];
    }
    catch (e) {
      filename = 'myfile.txt'
    }
    return filename
  }

  
  downloadFile() {
    this._fileService.downloadFile(this.file.uuid)
      .subscribe(
        (response: HttpResponse<Blob>) => {
          let filename: string = this.getFileName(response)
          let binaryData = [];
          binaryData.push(response.body);
          let downloadLink = document.createElement('a');
          downloadLink.href = window.URL.createObjectURL(new Blob(binaryData, { type: 'blob' }));
          downloadLink.setAttribute('download', filename);
          document.body.appendChild(downloadLink);
          downloadLink.click();
        }
      )
  }

  // service.ts
  downloadFile(uuid: string) {
    return this._http.get<Blob>(`${environment.apiUrl}/api/v1/file/${uuid}/package/`, { observe: 'response', responseType: 'blob' as 'json' })
  }

How to delete a specific line in a file?

To delete a specific line of a file by its line number:

Replace variables filename and line_to_delete with the name of your file and the line number you want to delete.

filename = 'foo.txt'
line_to_delete = 3
initial_line = 1
file_lines = {}

with open(filename) as f:
    content = f.readlines() 

for line in content:
    file_lines[initial_line] = line.strip()
    initial_line += 1

f = open(filename, "w")
for line_number, line_content in file_lines.items():
    if line_number != line_to_delete:
        f.write('{}\n'.format(line_content))

f.close()
print('Deleted line: {}'.format(line_to_delete))

Example output:

Deleted line: 3

Manually Triggering Form Validation using jQuery

You can't trigger the native validation UI (see edit below), but you can easily take advantage of the validation API on arbitrary input elements:

$('input').blur(function(event) {
    event.target.checkValidity();
}).bind('invalid', function(event) {
    setTimeout(function() { $(event.target).focus();}, 50);
});

The first event fires checkValidity on every input element as soon as it loses focus, if the element is invalid then the corresponding event will be fired and trapped by the second event handler. This one sets the focus back to the element, but that could be quite annoying, I assume you have a better solution for notifying about the errors. Here's a working example of my code above.

EDIT: All modern browsers support the reportValidity() method for native HTML5 validation, per this answer.

How to get the day name from a selected date?

try this:

DateTime.Now.DayOfWeek

Perfect 100% width of parent container for a Bootstrap input?

Just add box-sizing:

input[type="text"] {
    box-sizing: border-box;
}

How can I make grep print the lines below and above each matching line?

grep's -A 1 option will give you one line after; -B 1 will give you one line before; and -C 1 combines both to give you one line both before and after, -1 does the same.

How to use moment.js library in angular 2 typescript app?

We're using modules now,

try import {MomentModule} from 'angular2-moment/moment.module';

after npm install angular2-moment

http://ngmodules.org/modules/angular2-moment

No resource identifier found for attribute '...' in package 'com.app....'

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

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

I faced this problem when I try to import eclipse project into android studio

Click here to see screenshot

Ternary operator in PowerShell

PowerShell currently doesn't didn't have a native Inline If (or ternary If) but you could consider to use the custom cmdlet:

IIf <condition> <condition-is-true> <condition-is-false>

See: PowerShell inline If (IIf)

Remove duplicate rows in MySQL

If the IGNORE statement won't work like in my case, you can use the below statement:

CREATE TABLE your_table_deduped LIKE your_table;


INSERT your_table_deduped
SELECT *
FROM your_table
GROUP BY index1_id,
         index2_id;

RENAME TABLE your_table TO your_table_with_dupes;

RENAME TABLE your_table_deduped TO your_table;

#OPTIONAL
ALTER TABLE `your_table` ADD UNIQUE `unique_index` (`index1_id`, `index2_id`);

#OPTIONAL
DROP TABLE your_table_with_dupes;

Does Python SciPy need BLAS?

Following the instructions given by 'cfi' works for me, although there are a few pieces they left out that you might need:

1) Your lapack directory, after unzipping, may be called lapack-X-Y (some version number), so you can just rename that to LAPACK.

cd ~/src
mv lapack-[tab] LAPACK

2) In that directory, you may need to do:

cd ~/src/LAPACK 
cp lapack_LINUX.a libflapack.a

Get installed applications in a system

I agree that enumerating through the registry key is the best way.

Note, however, that the key given, @"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall", will list all applications in a 32-bit Windows installation, and 64-bit applications in a Windows 64-bit installation.

In order to also see 32-bit applications installed on a Windows 64-bit installation, you would also need to enumeration the key @"SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall".

Passing 'this' to an onclick event

The code that you have would work, but is executed from the global context, which means that this refers to the global object.

<script type="text/javascript">
var foo = function(param) {
    param.innerHTML = "Not a button";
};
</script>
<button onclick="foo(this)" id="bar">Button</button>

You can also use the non-inline alternative, which attached to and executed from the specific element context which allows you to access the element from this.

<script type="text/javascript">
document.getElementById('bar').onclick = function() {
    this.innerHTML = "Not a button";
};
</script>
<button id="bar">Button</button>

How to verify a Text present in the loaded page through WebDriver

If you want check only displayed objects(C#):

    public bool TextPresent(string text, int expectedNumberOfOccurrences)
    {
        var elements = Driver.FindElements(By.XPath(".//*[text()[contains(.,'" + text + "')]]"));
        var dispayedElements = 0;
        foreach (var webElement in elements)
        {
            if (webElement.Displayed)
            {
                dispayedElements++;
            }
        }
        var allExpectedElementsDisplayed = dispayedElements == expectedNumberOfOccurrences;
        return allExpectedElementsDisplayed;
    }

Check if TextBox is empty and return MessageBox?

Try this condition instead:

if (string.IsNullOrWhiteSpace(MaterialTextBox.Text)) {
    // Message box
}

This will take care of some strings that only contain whitespace characters and you won't have to deal with string equality which can sometimes be tricky

Number of days between past date and current date in Google spreadsheet

  1. Today() does return value in DATE format.

  2. Select your "Days left field" and paste this formula in the field =DAYS360(today(),C2)

  3. Go to Format > Number > More formats >Custom number format and select the number with no decimal numbers.

I tested, it works, at least in new version of Sheets, March 2015.

I want to remove double quotes from a String

this code is very better for show number in textbox

$(this) = [your textbox]

            var number = $(this).val();
            number = number.replace(/[',]+/g, '');
            number = number.toString().replace(/\B(?=(\d{3})+(?!\d))/g, ',');
            $(this).val(number); // "1,234,567,890"

How to convert image to byte array

Sample code to change an image into a byte array

public byte[] ImageToByteArray(System.Drawing.Image imageIn)
{
   using (var ms = new MemoryStream())
   {
      imageIn.Save(ms,imageIn.RawFormat);
      return  ms.ToArray();
   }
}

C# Image to Byte Array and Byte Array to Image Converter Class

Sorting a Python list by two fields

Sorting list of dicts using below will sort list in descending order on first column as salary and second column as age

d=[{'salary':123,'age':23},{'salary':123,'age':25}]
d=sorted(d, key=lambda i: (i['salary'], i['age']),reverse=True)

Output: [{'salary': 123, 'age': 25}, {'salary': 123, 'age': 23}]

Where is Developer Command Prompt for VS2013?

I'm using VS 2012, so I navigated to "C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Microsoft Visual Studio 2012\Visual Studio Tools" and ran as administrator this "Developer Command Prompt for VS2012" shortcut. In command shell I pasted the suggested

aspnet_regiis -i

and as I suspected this did not yield any success on Windows 10: enter image description here

So all I needed to do was "Turn Windows Features On/Off" at Control Panel and restart my machine to effect the changes. That did resolve the issue. Thanks.

Test if string is a number in Ruby on Rails

As of Ruby 2.6.0, the numeric cast-methods have an optional exception-argument [1]. This enables us to use the built-in methods without using exceptions as control flow:

Float('x') # => ArgumentError (invalid value for Float(): "x")
Float('x', exception: false) # => nil

Therefore, you don't have to define your own method, but can directly check variables like e.g.

if Float(my_var, exception: false)
  # do something if my_var is a float
end

Difference between a SOAP message and a WSDL?

Better analogy than the telephone call: Ordering products via postal mail from a mail-order service. The WSDL document is like the instructions that explain how to create the kind of order forms that the service provider will accept. A SOAP message is like an envelope with a standard design (size, shape, construction) that every post office around the world knows how to handle. You put your order form into such an envelope. The network (e.g. the internet) is the postal service. You put your envelope into the mail. The employees of the postal service do not look inside the envelope. The payload XML is the order form that you have enclosed in the envelope. After the post office delivers the envelope, the web service provider opens the envelope and processes the order form. If you have created and filled out the form correctly, they will mail the product that you ordered back to you.

How do you run a Python script as a service in Windows?

The simplest way is to use the: NSSM - the Non-Sucking Service Manager. Just download and unzip to a location of your choosing. It's a self-contained utility, around 300KB (much less than installing the entire pywin32 suite just for this purpose) and no "installation" is needed. The zip contains a 64-bit and a 32-bit version of the utility. Either should work well on current systems (you can use the 32-bit version to manage services on 64-bit systems).

GUI approach

1 - install the python program as a service. Open a Win prompt as admin

c:\>nssm.exe install WinService

2 - On NSSM´s GUI console:

path: C:\Python27\Python27.exe

Startup directory: C:\Python27

Arguments: c:\WinService.py

3 - check the created services on services.msc

Scripting approach (no GUI)

This is handy if your service should be part of an automated, non-interactive procedure, that may be beyond your control, such as a batch or installer script. It is assumed that the commands are executed with administrative privileges.

For convenience the commands are described here by simply referring to the utility as nssm.exe. It is advisable, however, to refer to it more explicitly in scripting with its full path c:\path\to\nssm.exe, since it's a self-contained executable that may be located in a private path that the system is not aware of.

1. Install the service

You must specify a name for the service, the path to the proper Python executable, and the path to the script:

nssm.exe install ProjectService "c:\path\to\python.exe" "c:\path\to\project\app\main.py"

More explicitly:

nssm.exe install ProjectService 
nssm.exe set ProjectService Application "c:\path\to\python.exe"
nssm.exe set ProjectService AppParameters "c:\path\to\project\app\main.py"

Alternatively you may want your Python app to be started as a Python module. One easy approach is to tell nssm that it needs to change to the proper starting directory, as you would do yourself when launching from a command shell:

nssm.exe install ProjectService "c:\path\to\python.exe" "-m app.main"
nssm.exe set ProjectService AppDirectory "c:\path\to\project"

This approach works well with virtual environments and self-contained (embedded) Python installs. Just make sure to have properly resolved any path issues in those environments with the usual methods. nssm has a way to set environment variables (e.g. PYTHONPATH) if needed, and can also launch batch scripts.

2. To start the service

nssm.exe start ProjectService 

3. To stop the service

nssm.exe stop ProjectService

4. To remove the service, specify the confirm parameter to skip the interactive confirmation.

nssm.exe remove ProjectService confirm

Check if object value exists within a Javascript array of objects and if not add a new object to array

You could prototype your array to make it more modular, try something like this

    Array.prototype.hasElement = function(element) {
        var i;
        for (i = 0; i < this.length; i++) {
            if (this[i] === element) {
                return i; //Returns element position, so it exists
            }
        }

        return -1; //The element isn't in your array
    };

And you can use it as:

 yourArray.hasElement(yourArrayElement)

Case insensitive comparison NSString

to check with the prefix as in the iPhone ContactApp

([string rangeOfString:prefixString options:NSCaseInsensitiveSearch].location == 0)

this blog was useful for me

Setting font on NSAttributedString on UITextView disregards line spacing

//For proper line spacing

NSString *text1 = @"Hello";
NSString *text2 = @"\nWorld";
UIFont *text1Font = [UIFont fontWithName:@"HelveticaNeue-Medium" size:10];
NSMutableAttributedString *attributedString1 =
[[NSMutableAttributedString alloc] initWithString:text1 attributes:@{ NSFontAttributeName : text1Font }];
NSMutableParagraphStyle *paragraphStyle1 = [[NSMutableParagraphStyle alloc] init];
[paragraphStyle1 setAlignment:NSTextAlignmentCenter];
[paragraphStyle1 setLineSpacing:4];
[attributedString1 addAttribute:NSParagraphStyleAttributeName value:paragraphStyle1 range:NSMakeRange(0, [attributedString1 length])];

UIFont *text2Font = [UIFont fontWithName:@"HelveticaNeue-Medium" size:16];
NSMutableAttributedString *attributedString2 =
[[NSMutableAttributedString alloc] initWithString:text2 attributes:@{NSFontAttributeName : text2Font }];
NSMutableParagraphStyle *paragraphStyle2 = [[NSMutableParagraphStyle alloc] init];
[paragraphStyle2 setLineSpacing:4];
[paragraphStyle2 setAlignment:NSTextAlignmentCenter];
[attributedString2 addAttribute:NSParagraphStyleAttributeName value:paragraphStyle2 range:NSMakeRange(0, [attributedString2 length])];

[attributedString1 appendAttributedString:attributedString2];

Clearing NSUserDefaults

If you need it while developing, you can also reset your simulator, deleting all the NSUserDefaults.

iOS Simulator -> Reset Content and Settings...

Bear in mind that it will also delete all the apps and files on simulator.

How to split a string after specific character in SQL Server and update this value to specific column

Use CHARINDEX. Perhaps make user function. If you use this split often.
I would create this function:

CREATE FUNCTION [dbo].[Split]
(
    @String VARCHAR(max),
    @Delimiter varCHAR(1)
)
RETURNS TABLE 
AS
RETURN 
(
    WITH Split(stpos,endpos) 
    AS(
        SELECT 0 AS stpos, CHARINDEX(@Delimiter,@String) AS endpos
        UNION ALL
        SELECT endpos+1, CHARINDEX(@Delimiter,@String,endpos+1)
            FROM Split
            WHERE endpos > 0
    )
    SELECT 'INT_COLUMN' = ROW_NUMBER() OVER (ORDER BY (SELECT 1)),
        'STRING_COLUMN' = SUBSTRING(@String,stpos,COALESCE(NULLIF(endpos,0),LEN(@String)+1)-stpos)
    FROM Split
)
GO

Opening the Settings app from another app

You can use this on iOS 5.0 and later: This no longer works.

[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"prefs://"]];

How do I generate a SALT in Java for Salted-Hash?

Another version using SHA-3, I am using bouncycastle:

The interface:

public interface IPasswords {

    /**
     * Generates a random salt.
     *
     * @return a byte array with a 64 byte length salt.
     */
    byte[] getSalt64();

    /**
     * Generates a random salt
     *
     * @return a byte array with a 32 byte length salt.
     */
    byte[] getSalt32();

    /**
     * Generates a new salt, minimum must be 32 bytes long, 64 bytes even better.
     *
     * @param size the size of the salt
     * @return a random salt.
     */
    byte[] getSalt(final int size);

    /**
     * Generates a new hashed password
     *
     * @param password to be hashed
     * @param salt the randomly generated salt
     * @return a hashed password
     */
    byte[] hash(final String password, final byte[] salt);

    /**
     * Expected password
     *
     * @param password to be verified
     * @param salt the generated salt (coming from database)
     * @param hash the generated hash (coming from database)
     * @return true if password matches, false otherwise
     */
    boolean isExpectedPassword(final String password, final byte[] salt, final byte[] hash);

    /**
     * Generates a random password
     *
     * @param length desired password length
     * @return a random password
     */
    String generateRandomPassword(final int length);
}

The implementation:

import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.Validate;
import org.apache.log4j.Logger;
import org.bouncycastle.jcajce.provider.digest.SHA3;

import java.io.Serializable;
import java.io.UnsupportedEncodingException;
import java.security.SecureRandom;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Random;

public final class Passwords implements IPasswords, Serializable {

    /*serialVersionUID*/
    private static final long serialVersionUID = 8036397974428641579L;
    private static final Logger LOGGER = Logger.getLogger(Passwords.class);
    private static final Random RANDOM = new SecureRandom();
    private static final int DEFAULT_SIZE = 64;
    private static final char[] symbols;

    static {
            final StringBuilder tmp = new StringBuilder();
            for (char ch = '0'; ch <= '9'; ++ch) {
                    tmp.append(ch);
            }
            for (char ch = 'a'; ch <= 'z'; ++ch) {
                    tmp.append(ch);
            }
            symbols = tmp.toString().toCharArray();
    }

    @Override public byte[] getSalt64() {
            return getSalt(DEFAULT_SIZE);
    }

    @Override public byte[] getSalt32() {
            return getSalt(32);
    }

    @Override public byte[] getSalt(int size) {
            final byte[] salt;
            if (size < 32) {
                    final String message = String.format("Size < 32, using default of: %d", DEFAULT_SIZE);
                    LOGGER.warn(message);
                    salt = new byte[DEFAULT_SIZE];
            } else {
                    salt = new byte[size];
            }
            RANDOM.nextBytes(salt);
            return salt;
    }

    @Override public byte[] hash(String password, byte[] salt) {

            Validate.notNull(password, "Password must not be null");
            Validate.notNull(salt, "Salt must not be null");

            try {
                    final byte[] passwordBytes = password.getBytes("UTF-8");
                    final byte[] all = ArrayUtils.addAll(passwordBytes, salt);
                    SHA3.DigestSHA3 md = new SHA3.Digest512();
                    md.update(all);
                    return md.digest();
            } catch (UnsupportedEncodingException e) {
                    final String message = String
                            .format("Caught UnsupportedEncodingException e: <%s>", e.getMessage());
                    LOGGER.error(message);
            }
            return new byte[0];
    }

    @Override public boolean isExpectedPassword(final String password, final byte[] salt, final byte[] hash) {

            Validate.notNull(password, "Password must not be null");
            Validate.notNull(salt, "Salt must not be null");
            Validate.notNull(hash, "Hash must not be null");

            try {
                    final byte[] passwordBytes = password.getBytes("UTF-8");
                    final byte[] all = ArrayUtils.addAll(passwordBytes, salt);

                    SHA3.DigestSHA3 md = new SHA3.Digest512();
                    md.update(all);
                    final byte[] digest = md.digest();
                    return Arrays.equals(digest, hash);
            }catch(UnsupportedEncodingException e){
                    final String message =
                            String.format("Caught UnsupportedEncodingException e: <%s>", e.getMessage());
                    LOGGER.error(message);
            }
            return false;


    }

    @Override public String generateRandomPassword(final int length) {

            if (length < 1) {
                    throw new IllegalArgumentException("length must be greater than 0");
            }

            final char[] buf = new char[length];
            for (int idx = 0; idx < buf.length; ++idx) {
                    buf[idx] = symbols[RANDOM.nextInt(symbols.length)];
            }
            return shuffle(new String(buf));
    }


    private String shuffle(final String input){
            final List<Character> characters = new ArrayList<Character>();
            for(char c:input.toCharArray()){
                    characters.add(c);
            }
            final StringBuilder output = new StringBuilder(input.length());
            while(characters.size()!=0){
                    int randPicker = (int)(Math.random()*characters.size());
                    output.append(characters.remove(randPicker));
            }
            return output.toString();
    }
}

The test cases:

public class PasswordsTest {

    private static final Logger LOGGER = Logger.getLogger(PasswordsTest.class);

    @Before
    public void setup(){
            BasicConfigurator.configure();
    }

    @Test
    public void testGeSalt() throws Exception {

            IPasswords passwords = new Passwords();
            final byte[] bytes = passwords.getSalt(0);
            int arrayLength = bytes.length;

            assertThat("Expected length is", arrayLength, is(64));
    }

    @Test
    public void testGeSalt32() throws Exception {
            IPasswords passwords = new Passwords();
            final byte[] bytes = passwords.getSalt32();
            int arrayLength = bytes.length;
            assertThat("Expected length is", arrayLength, is(32));
    }

    @Test
    public void testGeSalt64() throws Exception {
            IPasswords passwords = new Passwords();
            final byte[] bytes = passwords.getSalt64();
            int arrayLength = bytes.length;
            assertThat("Expected length is", arrayLength, is(64));
    }

    @Test
    public void testHash() throws Exception {
            IPasswords passwords = new Passwords();
            final byte[] hash = passwords.hash("holacomoestas", passwords.getSalt64());
            assertThat("Array is not null", hash, Matchers.notNullValue());
    }


    @Test
    public void testSHA3() throws UnsupportedEncodingException {
            SHA3.DigestSHA3 md = new SHA3.Digest256();
            md.update("holasa".getBytes("UTF-8"));
            final byte[] digest = md.digest();
             assertThat("expected digest is:",digest,Matchers.notNullValue());
    }

    @Test
    public void testIsExpectedPasswordIncorrect() throws Exception {

            String password = "givemebeer";
            IPasswords passwords = new Passwords();

            final byte[] salt64 = passwords.getSalt64();
            final byte[] hash = passwords.hash(password, salt64);
            //The salt and the hash go to database.

            final boolean isPasswordCorrect = passwords.isExpectedPassword("jfjdsjfsd", salt64, hash);

            assertThat("Password is not correct", isPasswordCorrect, is(false));

    }

    @Test
    public void testIsExpectedPasswordCorrect() throws Exception {
            String password = "givemebeer";
            IPasswords passwords = new Passwords();
            final byte[] salt64 = passwords.getSalt64();
            final byte[] hash = passwords.hash(password, salt64);
            //The salt and the hash go to database.
            final boolean isPasswordCorrect = passwords.isExpectedPassword("givemebeer", salt64, hash);
            assertThat("Password is correct", isPasswordCorrect, is(true));
    }

    @Test
    public void testGenerateRandomPassword() throws Exception {
            IPasswords passwords = new Passwords();
            final String randomPassword = passwords.generateRandomPassword(10);
            LOGGER.info(randomPassword);
            assertThat("Random password is not null", randomPassword, Matchers.notNullValue());
    }
}

pom.xml (only dependencies):

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.testng</groupId>
        <artifactId>testng</artifactId>
        <version>6.1.1</version>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>org.hamcrest</groupId>
        <artifactId>hamcrest-all</artifactId>
        <version>1.3</version>
        <scope>test</scope>
    </dependency>

    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.17</version>
    </dependency>

    <dependency>
        <groupId>org.bouncycastle</groupId>
        <artifactId>bcprov-jdk15on</artifactId>
        <version>1.51</version>
        <type>jar</type>
    </dependency>


    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-lang3</artifactId>
        <version>3.3.2</version>
    </dependency>


</dependencies>

Extract source code from .jar file

Above tools extract the jar. Also there are certain other tools and commands to extract the jar. But AFAIK you cant get the java code in case code has been obfuscated.

How to break out or exit a method in Java?

use return to exit from a method.

 public void someMethod() {
        //... a bunch of code ...
        if (someCondition()) {
            return;
        }
        //... otherwise do the following...
    }

Here's another example

int price = quantity * 5;
        if (hasCream) {
            price=price + 1;
        }
        if (haschocolat) {
            price=price + 2;
        }
        return price;

How do I apply a style to all children of an element

As commented by David Thomas, descendants of those child elements will (likely) inherit most of the styles assigned to those child elements.

You need to wrap your .myTestClass inside an element and apply the styles to descendants by adding .wrapper * descendant selector. Then, add .myTestClass > * child selector to apply the style to the elements children, not its grand children. For example like this:

JSFiddle - DEMO

_x000D_
_x000D_
.wrapper * {_x000D_
    color: blue;_x000D_
    margin: 0 100px; /* Only for demo */_x000D_
}_x000D_
.myTestClass > * {_x000D_
    color:red;_x000D_
    margin: 0 20px;_x000D_
}
_x000D_
<div class="wrapper">_x000D_
    <div class="myTestClass">Text 0_x000D_
        <div>Text 1</div>_x000D_
        <span>Text 1</span>_x000D_
        <div>Text 1_x000D_
            <p>Text 2</p>_x000D_
            <div>Text 2</div>_x000D_
        </div>_x000D_
        <p>Text 1</p>_x000D_
    </div>_x000D_
    <div>Text 0</div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Best way to store time (hh:mm) in a database

DATETIME start DATETIME end

I implore you to use two DATETIME values instead, labelled something like event_start and event_end.

Time is a complex business

Most of the world has now adopted the denery based metric system for most measurements, rightly or wrongly. This is good overall, because at least we can all agree that a g, is a ml, is a cubic cm. At least approximately so. The metric system has many flaws, but at least it's internationally consistently flawed.

With time however, we have; 1000 milliseconds in a second, 60 seconds to a minute, 60 minutes to an hour, 12 hours for each half a day, approximately 30 days per month which vary by the month and even year in question, each country has its time offset from others, the way time is formatted in each country vary.

It's a lot to digest, but the long and short of it is impossible for such a complex scenario to have a simple solution.

Some corners can be cut, but there are those where it is wiser not to

Although the top answer here suggests that you store an integer of minutes past midnight might seem perfectly reasonable, I have learned to avoid doing so the hard way.

The reasons to implement two DATETIME values are for an increase in accuracy, resolution and feedback.

These are all very handy for when the design produces undesirable results.

Am I storing more data than required?

It might initially appear like more information is being stored than I require, but there is a good reason to take this hit.

Storing this extra information almost always ends up saving me time and effort in the long-run, because I inevitably find that when somebody is told how long something took, they'll additionally want to know when and where the event took place too.

It's a huge planet

In the past, I have been guilty of ignoring that there are other countries on this planet aside from my own. It seemed like a good idea at the time, but this has ALWAYS resulted in problems, headaches and wasted time later on down the line. ALWAYS consider all time zones.

C#

A DateTime renders nicely to a string in C#. The ToString(string Format) method is compact and easy to read.

E.g.

new TimeSpan(EventStart.Ticks - EventEnd.Ticks).ToString("h'h 'm'm 's's'")

SQL server

Also if you're reading your database seperate to your application interface, then dateTimes are pleasnat to read at a glance and performing calculations on them are straightforward.

E.g.

SELECT DATEDIFF(MINUTE, event_start, event_end)

ISO8601 date standard

If using SQLite then you don't have this, so instead use a Text field and store it in ISO8601 format eg.

"2013-01-27T12:30:00+0000"

Notes:

  • This uses 24 hour clock*

  • The time offset (or +0000) part of the ISO8601 maps directly to longitude value of a GPS coordiate (not taking into account daylight saving or countrywide).

E.g.

TimeOffset=(±Longitude.24)/360 

...where ± refers to east or west direction.

It is therefore worth considering if it would be worth storing longitude, latitude and altitude along with the data. This will vary in application.

  • ISO8601 is an international format.

  • The wiki is very good for further details at http://en.wikipedia.org/wiki/ISO_8601.

  • The date and time is stored in international time and the offset is recorded depending on where in the world the time was stored.

In my experience there is always a need to store the full date and time, regardless of whether I think there is when I begin the project. ISO8601 is a very good, futureproof way of doing it.

Additional advice for free

It is also worth grouping events together like a chain. E.g. if recording a race, the whole event could be grouped by racer, race_circuit, circuit_checkpoints and circuit_laps.

In my experience, it is also wise to identify who stored the record. Either as a seperate table populated via trigger or as an additional column within the original table.

The more you put in, the more you get out

I completely understand the desire to be as economical with space as possible, but I would rarely do so at the expense of losing information.

A rule of thumb with databases is as the title says, a database can only tell you as much as it has data for, and it can be very costly to go back through historical data, filling in gaps.

The solution is to get it correct first time. This is certainly easier said than done, but you should now have a deeper insight of effective database design and subsequently stand a much improved chance of getting it right the first time.

The better your initial design, the less costly the repairs will be later on.

I only say all this, because if I could go back in time then it is what I'd tell myself when I got there.

Wildcard string comparison in Javascript

You could use Javascript's substring method. For example:

var list = ["bird1", "bird2", "pig1"]

for (var i = 0; i < list.length; i++) {
  if (list[i].substring(0,4) == "bird") {
   console.log(list[i]);
  }
}

Which outputs:

bird1
bird2

Basically, you're checking each item in the array to see if the first four letters are 'bird'. This does assume that 'bird' will always be at the front of the string.


So let's say your getting a pathname from a URL :

Let's say your at bird1?=letsfly - you could use this code to check the URL:

var listOfUrls = [
                  "bird1?=letsfly",
                  "bird",
                  "pigs?=dontfly",
                 ]

for (var i = 0; i < list.length; i++) {
  if (listOfUrls[i].substring(0,4) === 'bird') {
    // do something
  }
}

The above would match the first to URL's, but not the third (not the pig). You could easily swap out url.substring(0,4) with a regex, or even another javascript method like .contains()


Using the .contains() method might be a little more secure. You won't need to know which part of the URL 'bird' is at. For instance:

var url = 'www.example.com/bird?=fly'

if (url.contains('bird')) {
  // this is true
  // do something
}

Adding a UISegmentedControl to UITableView

   self.tableView.tableHeaderView = segmentedControl; 

If you want it to obey your width and height properly though enclose your segmentedControl in a UIView first as the tableView likes to mangle your view a bit to fit the width.

enter image description here enter image description here

How to delete session cookie in Postman?

I think the response of aaron can be enhanced for URL that contains variables:

var sdk = require('postman-collection');      

const testURL=pm.environment.values.substitute(pm.request.url, null, false);

const objURL=new sdk.Url(testURL);

console.log("clearing cookies for: "+testURL);

const jar = pm.cookies.jar();

jar.clear(objURL, function (error) {
  // error - <Error>
  if(error)
  console.log("Error clearing cookies: "+error);
});

How to do left join in Doctrine?

If you have an association on a property pointing to the user (let's say Credit\Entity\UserCreditHistory#user, picked from your example), then the syntax is quite simple:

public function getHistory($users) {
    $qb = $this->entityManager->createQueryBuilder();
    $qb
        ->select('a', 'u')
        ->from('Credit\Entity\UserCreditHistory', 'a')
        ->leftJoin('a.user', 'u')
        ->where('u = :user')
        ->setParameter('user', $users)
        ->orderBy('a.created_at', 'DESC');

    return $qb->getQuery()->getResult();
}

Since you are applying a condition on the joined result here, using a LEFT JOIN or simply JOIN is the same.

If no association is available, then the query looks like following

public function getHistory($users) {
    $qb = $this->entityManager->createQueryBuilder();
    $qb
        ->select('a', 'u')
        ->from('Credit\Entity\UserCreditHistory', 'a')
        ->leftJoin(
            'User\Entity\User',
            'u',
            \Doctrine\ORM\Query\Expr\Join::WITH,
            'a.user = u.id'
        )
        ->where('u = :user')
        ->setParameter('user', $users)
        ->orderBy('a.created_at', 'DESC');

    return $qb->getQuery()->getResult();
}

This will produce a resultset that looks like following:

array(
    array(
        0 => UserCreditHistory instance,
        1 => Userinstance,
    ),
    array(
        0 => UserCreditHistory instance,
        1 => Userinstance,
    ),
    // ...
)

how to insert a new line character in a string to PrintStream then use a scanner to re-read the file

The linefeed character \n is not the line separator in certain operating systems (such as windows, where it's "\r\n") - my suggestion is that you use \r\n instead, then it'll both see the line-break with only \n and \r\n, I've never had any problems using it.

Also, you should look into using a StringBuilder instead of concatenating the String in the while-loop at BookCatalog.toString(), it is a lot more effective. For instance:

public String toString() {
        BookNode current = front;
        StringBuilder sb = new StringBuilder();
        while (current!=null){
            sb.append(current.getData().toString()+"\r\n ");
            current = current.getNext();
        }
        return sb.toString();
}

Should ol/ul be inside <p> or outside?

actually you should only put in-line elements inside the p, so in your case ol is better outside

How to find indices of all occurrences of one string in another in JavaScript?

If you just want to find the position of all matches I'd like to point you to a little hack:

_x000D_
_x000D_
var haystack = 'I learned to play the Ukulele in Lebanon.',
    needle = 'le',
    splitOnFound = haystack.split(needle).map(function (culm)
    {
        return this.pos += culm.length + needle.length
    }, {pos: -needle.length}).slice(0, -1); // {pos: ...} – Object wich is used as this

console.log(splitOnFound);
_x000D_
_x000D_
_x000D_

It might not be applikable if you have a RegExp with variable length but for some it might be helpful.

This is case sensitive. For case insensitivity use String.toLowerCase function before.

Android - get children inside a View?

for(int index = 0; index < ((ViewGroup) viewGroup).getChildCount(); index++) {
    View nextChild = ((ViewGroup) viewGroup).getChildAt(index);
}

Will that do?

Determining whether an object is a member of a collection in VBA

this version works for primitive types and for classes (short test-method included)

' TODO: change this to the name of your module
Private Const sMODULE As String = "MVbaUtils"

Public Function ExistsInCollection(oCollection As Collection, sKey As String) As Boolean
    Const scSOURCE As String = "ExistsInCollection"

    Dim lErrNumber As Long
    Dim sErrDescription As String

    lErrNumber = 0
    sErrDescription = "unknown error occurred"
    Err.Clear
    On Error Resume Next
        ' note: just access the item - no need to assign it to a dummy value
        ' and this would not be so easy, because we would need different
        ' code depending on the type of object
        ' e.g.
        '   Dim vItem as Variant
        '   If VarType(oCollection.Item(sKey)) = vbObject Then
        '       Set vItem = oCollection.Item(sKey)
        '   Else
        '       vItem = oCollection.Item(sKey)
        '   End If
        oCollection.Item sKey
        lErrNumber = CLng(Err.Number)
        sErrDescription = Err.Description
    On Error GoTo 0

    If lErrNumber = 5 Then ' 5 = not in collection
        ExistsInCollection = False
    ElseIf (lErrNumber = 0) Then
        ExistsInCollection = True
    Else
        ' Re-raise error
        Err.Raise lErrNumber, mscMODULE & ":" & scSOURCE, sErrDescription
    End If
End Function

Private Sub Test_ExistsInCollection()
    Dim asTest As New Collection

    Debug.Assert Not ExistsInCollection(asTest, "")
    Debug.Assert Not ExistsInCollection(asTest, "xx")

    asTest.Add "item1", "key1"
    asTest.Add "item2", "key2"
    asTest.Add New Collection, "key3"
    asTest.Add Nothing, "key4"
    Debug.Assert ExistsInCollection(asTest, "key1")
    Debug.Assert ExistsInCollection(asTest, "key2")
    Debug.Assert ExistsInCollection(asTest, "key3")
    Debug.Assert ExistsInCollection(asTest, "key4")
    Debug.Assert Not ExistsInCollection(asTest, "abcx")

    Debug.Print "ExistsInCollection is okay"
End Sub

Open Source Javascript PDF viewer

Well it's not even close to the full spec, but there is a JavaScript and Canvas based PDF viewer out there.

Using an HTML button to call a JavaScript function

Your HTML and the way you call the function from the button look correct.

The problem appears to be in the CapacityCount function. I'm getting this error in my console on Firefox 3.5: "document.all is undefined" on line 759 of bendelcorp.js.

Edit:

Looks like document.all is an IE-only thing and is a nonstandard way of accessing the DOM. If you use document.getElementById(), it should probably work. Example: document.getElementById("RUnits").value instead of document.all.Capacity.RUnits.value

Excel VBA, How to select rows based on data in a column?

The easiest way to do it is to use the End method, which is gives you the cell that you reach by pressing the end key and then a direction when you're on a cell (in this case B6). This won't give you what you expect if B6 or B7 is empty, though.

Dim start_cell As Range
Set start_cell = Range("[Workbook1.xlsx]Sheet1!B6")
Range(start_cell, start_cell.End(xlDown)).Copy Range("[Workbook2.xlsx]Sheet1!A2")

If you can't use End, then you would have to use a loop.

Dim start_cell As Range, end_cell As Range

Set start_cell = Range("[Workbook1.xlsx]Sheet1!B6")
Set end_cell = start_cell

Do Until IsEmpty(end_cell.Offset(1, 0))
    Set end_cell = end_cell.Offset(1, 0)
Loop

Range(start_cell, end_cell).Copy Range("[Workbook2.xlsx]Sheet1!A2")

Iterate Multi-Dimensional Array with Nested Foreach Statement

I was looking for a solution to enumerate an array of an unknown at compile time rank with an access to every element indices set. I saw solutions with yield but here is another implementation with no yield. It is in old school minimalistic way. In this example AppendArrayDebug() just prints all the elements into StringBuilder buffer.

public static void AppendArrayDebug ( StringBuilder sb, Array array )
{
    if( array == null || array.Length == 0 )
    {
        sb.Append( "<nothing>" );
        return;
    }

    int i;

    var rank = array.Rank;
    var lastIndex = rank - 1;

    // Initialize indices and their boundaries
    var indices = new int[rank];
    var lower = new int[rank];
    var upper = new int[rank];
    for( i = 0; i < rank; ++i )
    {
        indices[i] = lower[i] = array.GetLowerBound( i );
        upper[i] = array.GetUpperBound( i );
    }

    while( true )
    {
        BeginMainLoop:

        // Begin work with an element

        var element = array.GetValue( indices );

        sb.AppendLine();
        sb.Append( '[' );
        for( i = 0; i < rank; ++i )
        {
            sb.Append( indices[i] );
            sb.Append( ' ' );
        }
        sb.Length -= 1;
        sb.Append( "] = " );
        sb.Append( element );

        // End work with the element

        // Increment index set

        // All indices except the first one are enumerated several times
        for( i = lastIndex; i > 0; )
        {
            if( ++indices[i] <= upper[i] )
                goto BeginMainLoop;
            indices[i] = lower[i];
            --i;
        }

        // Special case for the first index, it must be enumerated only once
        if( ++indices[0] > upper[0] )
            break;
    }
}

For example the following array will produce the following output:

var array = new [,,]
{
    { {  1,  2,  3 }, {  4,  5,  6 }, {  7,  8,  9 }, { 10, 11, 12 } },
    { { 13, 14, 15 }, { 16, 17, 18 }, { 19, 20, 21 }, { 22, 23, 24 } }
};

/*
Output:

[0 0 0] = 1
[0 0 1] = 2
[0 0 2] = 3
[0 1 0] = 4
[0 1 1] = 5
[0 1 2] = 6
[0 2 0] = 7
[0 2 1] = 8
[0 2 2] = 9
[0 3 0] = 10
[0 3 1] = 11
[0 3 2] = 12
[1 0 0] = 13
[1 0 1] = 14
[1 0 2] = 15
[1 1 0] = 16
[1 1 1] = 17
[1 1 2] = 18
[1 2 0] = 19
[1 2 1] = 20
[1 2 2] = 21
[1 3 0] = 22
[1 3 1] = 23
[1 3 2] = 24
*/

twitter bootstrap typeahead ajax example

You can use the BS Typeahead fork which supports ajax calls. Then you will be able to write:

$('.typeahead').typeahead({
    source: function (typeahead, query) {
        return $.get('/typeahead', { query: query }, function (data) {
            return typeahead.process(data);
        });
    }
});

What does "static" mean in C?

There is one more use not covered here, and that is as part of an array type declaration as an argument to a function:

int someFunction(char arg[static 10])
{
    ...
}

In this context, this specifies that arguments passed to this function must be an array of type char with at least 10 elements in it. For more info see my question here.

how to set value of a input hidden field through javascript?

You need to run your script after the element exists. Move the <input type="hidden" name="checkyear" id="checkyear" value=""> to the beginning.

EXCEL Multiple Ranges - need different answers for each range

use

=VLOOKUP(D4,F4:G9,2)

with the range F4:G9:

0   0.1
1   0.15
5   0.2
15  0.3
30  1
100 1.3

and D4 being the value in question, e.g. 18.75 -> result: 0.3

Setting a WebRequest's body data

Update

See my other SO answer.


Original

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

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

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

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

Determine whether an array contains a value

My little contribution:

function isInArray(array, search)
{
    return array.indexOf(search) >= 0;
}

//usage
if(isInArray(my_array, "my_value"))
{
    //...
}

How to check if file already exists in the folder

'In Visual Basic

Dim FileName = "newfile.xml" ' The Name of file with its Extension Example A.txt or A.xml

Dim FilePath ="C:\MyFolderName" & "\" & FileName  'First Name of Directory and Then Name of Folder if it exists and then attach the name of file you want to search.

If System.IO.File.Exists(FilePath) Then
    MsgBox("The file exists")
Else
    MsgBox("the file doesn't exist")
End If

How to get the index of an element in an IEnumerable?

A few years later, but this uses Linq, returns -1 if not found, doesn't create extra objects, and should short-circuit when found [as opposed to iterating over the entire IEnumerable]:

public static int IndexOf<T>(this IEnumerable<T> list, T item)
{
    return list.Select((x, index) => EqualityComparer<T>.Default.Equals(item, x)
                                     ? index
                                     : -1)
               .FirstOr(x => x != -1, -1);
}

Where 'FirstOr' is:

public static T FirstOr<T>(this IEnumerable<T> source, T alternate)
{
    return source.DefaultIfEmpty(alternate)
                 .First();
}

public static T FirstOr<T>(this IEnumerable<T> source, Func<T, bool> predicate, T alternate)
{
    return source.Where(predicate)
                 .FirstOr(alternate);
}

SQL select only rows with max value on a column

A third solution I hardly ever see mentioned is MySQL specific and looks like this:

SELECT id, MAX(rev) AS rev
 , 0+SUBSTRING_INDEX(GROUP_CONCAT(numeric_content ORDER BY rev DESC), ',', 1) AS numeric_content
FROM t1
GROUP BY id

Yes it looks awful (converting to string and back etc.) but in my experience it's usually faster than the other solutions. Maybe that just for my use cases, but I have used it on tables with millions of records and many unique ids. Maybe it's because MySQL is pretty bad at optimizing the other solutions (at least in the 5.0 days when I came up with this solution).

One important thing is that GROUP_CONCAT has a maximum length for the string it can build up. You probably want to raise this limit by setting the group_concat_max_len variable. And keep in mind that this will be a limit on scaling if you have a large number of rows.

Anyway, the above doesn't directly work if your content field is already text. In that case you probably want to use a different separator, like \0 maybe. You'll also run into the group_concat_max_len limit quicker.

Get type of all variables

R/Rscript doesn't have concrete datatypes.

R interpreter has a duck-typing memory allocation system. There is no builtin method to tell you the datatype of your pointer to memory. Duck typing is done for speed, but turned out to be a bad idea because now statements such as: print(is.integer(5)) returns FALSE and is.integer(as.integer(5)) returns TRUE. Go figure.

The R-manual on basic types: https://cran.r-project.org/doc/manuals/R-lang.html#Basic-types

The best you can hope for is to write your own function to probe your pointer to memory, then use process of elimination to decide if it is suitable for your needs.

If your variable is a global or an object:

Your object() needs to be penetrated with get(...) before you can see inside. Example:

a <- 10
myGlobals <- objects()
for(i in myGlobals){
  typeof(i)         #prints character
  typeof(get(i))    #prints integer
}

typeof(...) probes your variable pointer to memory:

The R function typeof has a bias to give you the type at maximum depth, for example.

library(tibble)

#expression              notes                                  type
#----------------------- -------------------------------------- ----------
typeof(TRUE)             #a single boolean:                     logical
typeof(1L)               #a single numeric with L postfixed:    integer
typeof("foobar")         #A single string in double quotes:     character
typeof(1)                #a single numeric:                     double
typeof(list(5,6,7))      #a list of numeric:                    list
typeof(2i)               #an imaginary number                   complex

typeof(5 + 5L)           #double + integer is coerced:          double
typeof(c())              #an empty vector has no type:          NULL
typeof(!5)               #a bang before a double:               logical
typeof(Inf)              #infinity has a type:                  double
typeof(c(5,6,7))         #a vector containing only doubles:     double
typeof(c(c(TRUE)))       #a vector of vector of logicals:       logical
typeof(matrix(1:10))     #a matrix of doubles has a type:       list

typeof(substr("abc",2,2))#a string at index 2 which is 'b' is:  character
typeof(c(5L,6L,7L))      #a vector containing only integers:    integer
typeof(c(NA,NA,NA))      #a vector containing only NA:          logical
typeof(data.frame())     #a data.frame with nothing in it:      list
typeof(data.frame(c(3))) #a data.frame with a double in it:     list
typeof(c("foobar"))      #a vector containing only strings:     character
typeof(pi)               #builtin expression for pi:            double

typeof(1.66)             #a single numeric with mantissa:       double
typeof(1.66L)            #a double with L postfixed             double
typeof(c("foobar"))      #a vector containing only strings:     character
typeof(c(5L, 6L))        #a vector containing only integers:    integer
typeof(c(1.5, 2.5))      #a vector containing only doubles:     double
typeof(c(1.5, 2.5))      #a vector containing only doubles:     double
typeof(c(TRUE, FALSE))   #a vector containing only logicals:    logical

typeof(factor())         #an empty factor has default type:     integer
typeof(factor(3.14))     #a factor containing doubles:          integer
typeof(factor(T, F))     #a factor containing logicals:         integer
typeof(Sys.Date())       #builtin R dates:                      double
typeof(hms::hms(3600))   #hour minute second timestamp          double
typeof(c(T, F))          #T and F are builtins:                 logical
typeof(1:10)             #a builtin sequence of numerics:       integer
typeof(NA)               #The builtin value not available:      logical

typeof(c(list(T)))       #a vector of lists of logical:         list
typeof(list(c(T)))       #a list of vectors of logical:         list
typeof(c(T, 3.14))       #a vector of logicals and doubles:     double
typeof(c(3.14, "foo"))   #a vector of doubles and characters:   character
typeof(c("foo",list(T))) #a vector of strings and lists:        list
typeof(list("foo",c(T))) #a list of strings and vectors:        list
typeof(TRUE + 5L)        #a logical plus an integer:            integer
typeof(c(TRUE, 5L)[1])   #The true is coerced to 1              integer
typeof(c(c(2i), TRUE)[1])#logical coerced to complex:           complex
typeof(c(NaN, 'batman')) #NaN's in a vector don't dominate:     character
typeof(5 && 4)           #doubles are coerced by order of &&    logical
typeof(8 < 'foobar')     #string and double is coerced          logical
typeof(list(4, T)[[1]])  #a list retains type at every index:   double
typeof(list(4, T)[[2]])  #a list retains type at every index:   logical
typeof(2 ** 5)           #result of exponentiation              double
typeof(0E0)              #exponential lol notation              double
typeof(0x3fade)          #hexidecimal                           double
typeof(paste(3, '3'))    #paste promotes types to string        character
typeof(3 + ?)           #R pukes on unicode                    error
typeof(iconv("a", "latin1", "UTF-8")) #UTF-8 characters         character
typeof(5 == 5)           #result of a comparison:               logical

class(...) probes your variable pointer to memory:

The R function class has a bias to give you the type of container or structure encapsulating your types, for example.

library(tibble)

#expression            notes                                    class
#--------------------- ---------------------------------------- ---------
class(matrix(1:10))     #a matrix of doubles has a class:       matrix
class(factor("hi"))     #factor of items is:                    factor
class(TRUE)             #a single boolean:                      logical
class(1L)               #a single numeric with L postfixed:     integer
class("foobar")         #A single string in double quotes:      character
class(1)                #a single numeric:                      numeric
class(list(5,6,7))      #a list of numeric:                     list
class(2i)               #an imaginary                           complex
class(data.frame())     #a data.frame with nothing in it:       data.frame
class(Sys.Date())       #builtin R dates:                       Date
class(sapply)           #a function is                          function
class(charToRaw("hi"))  #convert string to raw:                 raw
class(array("hi"))      #array of items is:                     array

class(5 + 5L)           #double + integer is coerced:          numeric
class(c())              #an empty vector has no class:         NULL
class(!5)               #a bang before a double:               logical
class(Inf)              #infinity has a class:                 numeric
class(c(5,6,7))         #a vector containing only doubles:     numeric
class(c(c(TRUE)))       #a vector of vector of logicals:       logical

class(substr("abc",2,2))#a string at index 2 which is 'b' is:  character
class(c(5L,6L,7L))      #a vector containing only integers:    integer
class(c(NA,NA,NA))      #a vector containing only NA:          logical
class(data.frame(c(3))) #a data.frame with a double in it:     data.frame
class(c("foobar"))      #a vector containing only strings:     character
class(pi)               #builtin expression for pi:            numeric

class(1.66)             #a single numeric with mantissa:       numeric
class(1.66L)            #a double with L postfixed             numeric
class(c("foobar"))      #a vector containing only strings:     character
class(c(5L, 6L))        #a vector containing only integers:    integer
class(c(1.5, 2.5))      #a vector containing only doubles:     numeric
class(c(TRUE, FALSE))   #a vector containing only logicals:    logical

class(factor())       #an empty factor has default class:      factor
class(factor(3.14))   #a factor containing doubles:            factor
class(factor(T, F))   #a factor containing logicals:           factor
class(hms::hms(3600)) #hour minute second timestamp            hms difftime
class(c(T, F))        #T and F are builtins:                   logical
class(1:10)           #a builtin sequence of numerics:         integer
class(NA)             #The builtin value not available:        logical

class(c(list(T)))       #a vector of lists of logical:         list
class(list(c(T)))       #a list of vectors of logical:         list
class(c(T, 3.14))       #a vector of logicals and doubles:     numeric
class(c(3.14, "foo"))   #a vector of doubles and characters:   character
class(c("foo",list(T))) #a vector of strings and lists:        list
class(list("foo",c(T))) #a list of strings and vectors:        list
class(TRUE + 5L)        #a logical plus an integer:            integer
class(c(TRUE, 5L)[1])   #The true is coerced to 1              integer
class(c(c(2i), TRUE)[1])#logical coerced to complex:           complex
class(c(NaN, 'batman')) #NaN's in a vector don't dominate:     character
class(5 && 4)           #doubles are coerced by order of &&    logical
class(8 < 'foobar')     #string and double is coerced          logical
class(list(4, T)[[1]])  #a list retains class at every index:  numeric
class(list(4, T)[[2]])  #a list retains class at every index:  logical
class(2 ** 5)           #result of exponentiation              numeric
class(0E0)              #exponential lol notation              numeric
class(0x3fade)          #hexidecimal                           numeric
class(paste(3, '3'))     #paste promotes class to string       character
class(3 + ?)           #R pukes on unicode                   error
class(iconv("a", "latin1", "UTF-8")) #UTF-8 characters         character
class(5 == 5)           #result of a comparison:               logical

Get the data storage.mode of your variable:

When an R variable is written to disk, the data layout changes again, and is called the data's storage.mode. The function storage.mode(...) reveals this low level information: see Mode, Class, and Type of R objects. You shouldn't need to worry about R's storage.mode unless you are trying to understand delays caused by round trip casts/coercions that occur when assigning and reading data to and from disk.

Demo: R/Rscript gettype(your_variable):

Run this R code then adapt it for your purposes, it'll make a pretty good guess as to what type it is.

get_type <- function(variable){ 
  sz <- as.integer(length(variable)) #length of your variable 
  tof <- typeof(variable)            #typeof your variable 
  cls <- class(variable)             #class of your variable 
  isc <- is.character(variable)      #what is.character() has to say about it.  
  d <- dim(variable)                 #dimensions of your variable 
  isv <- is.vector(variable) 
  if (is.matrix(variable)){  
    d <- dim(t(variable))             #dimensions of your matrix
  }    
  #observations ----> datatype 
  if (sz>=1 && tof == "logical" && cls == "logical" && isv == TRUE){ return("vector of logical") } 
  if (sz>=1 && tof == "integer" && cls == "integer" ){ return("vector of integer") } 
  if (sz==1 && tof == "double"  && cls == "Date" ){ return("Date") } 
  if (sz>=1 && tof == "raw"     && cls == "raw" ){ return("vector of raw") } 
  if (sz>=1 && tof == "double"  && cls == "numeric" ){ return("vector of double") } 
  if (sz>=1 && tof == "double"  && cls == "array" ){ return("vector of array of double") } 
  if (sz>=1 && tof == "character"  && cls == "array" ){ return("vector of array of character") } 
  if (sz>=0 && tof == "list"       && cls == "data.frame" ){ return("data.frame") } 
  if (sz>=1 && isc == TRUE         && isv == TRUE){ return("vector of character") } 
  if (sz>=1 && tof == "complex"    && cls == "complex" ){ return("vector of complex") } 
  if (sz==0 && tof == "NULL"       && cls == "NULL" ){ return("NULL") } 
  if (sz>=0 && tof == "integer"    && cls == "factor" ){ return("factor") } 
  if (sz>=1 && tof == "double"     && cls == "numeric" && isv == TRUE){ return("vector of double") } 
  if (sz>=1 && tof == "double"     && cls == "matrix"){ return("matrix of double") } 
  if (sz>=1 && tof == "character"  && cls == "matrix"){ return("matrix of character") } 
  if (sz>=1 && tof == "list"       && cls == "list" && isv == TRUE){ return("vector of list") } 
  if (sz>=1 && tof == "closure"    && cls == "function" && isv == FALSE){ return("closure/function") } 
  return("it's pointer to memory, bruh") 
} 
assert <- function(a, b){ 
  if (a == b){ 
    cat("P") 
  } 
  else{ 
    cat("\nFAIL!!!  Sniff test:\n") 
    sz <- as.integer(length(variable))   #length of your variable 
    tof <- typeof(variable)              #typeof your variable 
    cls <- class(variable)               #class of your variable 
    isc <- is.character(variable)        #what is.character() has to say about it. 
    d <- dim(variable)                   #dimensions of your variable 
    isv <- is.vector(variable) 
    if (is.matrix(variable)){  
      d <- dim(t(variable))                   #dimensions of your variable 
    } 
    if (!is.function(variable)){ 
      print(paste("value: '", variable, "'")) 
    } 
    print(paste("get_type said: '", a, "'")) 
    print(paste("supposed to be: '", b, "'")) 
 
    cat("\nYour pointer to memory has properties:\n")  
    print(paste("sz: '", sz, "'")) 
    print(paste("tof: '", tof, "'")) 
    print(paste("cls: '", cls, "'")) 
    print(paste("d: '", d, "'")) 
    print(paste("isc: '", isc, "'")) 
    print(paste("isv: '", isv, "'")) 
    quit() 
  } 
}
#these asserts give a sample for exercising the code. 
assert(get_type(TRUE),      "vector of logical")  #everything is a vector in R by default. 
assert(get_type(c(TRUE)),   "vector of logical")  #c() just casts to vector 
assert(get_type(c(c(TRUE))),"vector of logical")  #casting vector multiple times does nothing 
assert(get_type(!5),        "vector of logical")  #bang inflicts 'not truth-like' 
assert(get_type(1L),              "vector of integer")   #naked integers are still vectors of 1 
assert(get_type(c(1L, 2L)),       "vector of integer")   #Longs are not doubles 
assert(get_type(c(1L, c(2L, 3L))),"vector of integer")   #nested vectors of integers 
assert(get_type(c(1L, c(TRUE))),  "vector of integer")   #logicals coerced to integer 
assert(get_type(c(FALSE, c(1L))), "vector of integer")   #logicals coerced to integer 
assert(get_type("foobar"),        "vector of character")    #character here means 'string' 
assert(get_type(c(1L, "foobar")), "vector of character")    #integers are coerced to string 
assert(get_type(5),           "vector of double") 
assert(get_type(5 + 5L),      "vector of double") 
assert(get_type(Inf),         "vector of double") 
assert(get_type(c(5,6,7)),    "vector of double") 
assert(get_type(NaN),           "vector of double") 
assert(get_type(list(5)),       "vector of list")    #your list is in a vector. 
assert(get_type(list(5,6,7)),   "vector of list") 
assert(get_type(c(list(5,6,7))),"vector of list") 
assert(get_type(list(c(5,6),T)),"vector of list")    #vector of list of vector and logical 
assert(get_type(list(5,6,7)),   "vector of list") 
assert(get_type(2i),            "vector of complex") 
assert(get_type(c(2i, 3i, 4i)), "vector of complex") 
assert(get_type(c()),            "NULL") 
assert(get_type(data.frame()),   "data.frame") 
assert(get_type(data.frame(4,5)),"data.frame") 
assert(get_type(Sys.Date()),     "Date") 
assert(get_type(sapply),         "closure/function") 
assert(get_type(charToRaw("hi")),"vector of raw") 
assert(get_type(c(charToRaw("a"), charToRaw("b"))), "vector of raw") 
assert(get_type(array(4)),       "vector of array of double") 
assert(get_type(array(4,5)),     "vector of array of double") 
assert(get_type(array("hi")),    "vector of array of character") 
assert(get_type(factor()),       "factor") 
assert(get_type(factor(3.14)),   "factor") 
assert(get_type(factor(TRUE)),   "factor") 
assert(get_type(matrix(3,4,5)),  "matrix of double") 
assert(get_type(as.matrix(5)),   "matrix of double") 
assert(get_type(matrix("yatta")),"matrix of character") 

I put in a C++/Java/Python ideology here that gives me the scoop of what the memory most looks like. R triad typing system is like trying to nail spaghetti to the wall, <- and <<- will package your matrix to a list when you least suspect. As the old duck-typing saying goes: If it waddles like a duck and if it quacks like a duck and if it has feathers, then it's a duck.

why are there two different kinds of for loops in java?

The for-each loop was introduced in Java 1.5 and is used with collections (and to be pedantic, arrays, and anything implementing the Iterable<E> interface ... which the article notes):

http://download.oracle.com/javase/1,5.0/docs/guide/language/foreach.html

A completely free agile software process tool

Try http://www.icescrum.org . It is free to use. And it has lot of cool features. Perfect for scrum teams.

List of IP Space used by Facebook

# Bloqueio facebook
for ip in `whois -h whois.radb.net '!gAS32934' | grep /`
do
  iptables -A FORWARD -p all -d $ip -j REJECT
done

Error :Request header field Content-Type is not allowed by Access-Control-Allow-Headers

As hinted at by this post Error in chrome: Content-Type is not allowed by Access-Control-Allow-Headers just add the additional header to your web.config like so...

<httpProtocol>
  <customHeaders>
    <add name="Access-Control-Allow-Origin" value="*" />
    <add name="Access-Control-Allow-Headers" value="Origin, X-Requested-With, Content-Type, Accept" />
  </customHeaders>
</httpProtocol>

Retrieving the COM class factory for component with CLSID {XXXX} failed due to the following error: 80040154

Had a related issue with a different, but similar fix:

I had a Windows service project set to "Any-CPU" using a 64-bit DLL. Same error message. Tried a whole bunch of things, but nothing worked. Finally, I went into project Properties -> Build and noticed that project had "Prefer 32-bit" checked. Unchecked this and no more error.

My guess is that the windows service was expecting a 32-bit DLL, and couldn't find it.

No content to map due to end-of-input jackson parser

In my case I was reading the stream in a jersey RequestEventListener I created on the server side to log the request body prior to the request being processed. I then realized that this probably resulted in the subsequent read to yield no string (which is what is passed over when the business logic is run). I verified that to be the case.

So if you are using streams to read the JSON string be careful of that.

How do I return JSON without using a template in Django?

Here's an example I needed for conditionally rendering json or html depending on the Request's Accept header

# myapp/views.py
from django.core import serializers                                                                                
from django.http import HttpResponse                                                                                  
from django.shortcuts import render                                                                                   
from .models import Event

def event_index(request):                                                                                             
    event_list = Event.objects.all()                                                                                  
    if request.META['HTTP_ACCEPT'] == 'application/json':                                                             
        response = serializers.serialize('json', event_list)                                                          
        return HttpResponse(response, content_type='application/json')                                                
    else:                                                                                                             
        context = {'event_list': event_list}                                                                          
        return render(request, 'polls/event_list.html', context)

you can test this with curl or httpie

$ http localhost:8000/event/
$ http localhost:8000/event/ Accept:application/json

note I opted not to use JsonReponse as that would reserialize the model unnecessarily.

TypeError: 'float' object is not callable

The problem is with -3.7(prof[x]), which looks like a function call (note the parens). Just use a * like this -3.7*prof[x].

How to sort by dates excel?

It's actually really easy. Highlight the DATE column and make sure that its set as date in Excel. Highlight everything you want to change, Then go to [DATA]>[SORT]>[COLUMN] and set sorting by date. Hope it helps.

how to make div click-able?

As you updated your question, here's an obtrustive example:

window.onload = function()
{
    var div = document.getElementById("mydiv");

    div.style.cursor = 'pointer';
    div.onmouseover = function()
    {
        div.style.background = "#ff00ff";
    };
}

Error:Unable to locate adb within SDK in Android Studio

For anyone who is still running into this issue. I had a similar problem where I could see my device from adb on the command line using adb devices but Android Studio would not recognize when I had a device attached and would throw either:

  • Unable to locate adb within SDK or
  • Unable to obtain result of 'adb version'

    I had tried start/stops of adb, uninstalls, of platform-tools, and more. What I found was that inside my C:\Users\<UserName>\AppData\Local\Android folder I had multiple sdk folders. I performed the following:

    1. Unistall Platform-Tools using Android Studio's SDK Manager
    2. Deleted all platform-tools\ directories within each C:\Users\<UserName>\AppData\Local\Android\sdk* directory
    3. Reinstalled Platform-Tools using Android Studio's SDK Manager

Hope this helps someone someday with their issue.

How to increase the timeout period of web service in asp.net?

In app.config file (or .exe.config) you can add or change the "receiveTimeout" property in binding. like this

<binding name="WebServiceName" receiveTimeout="00:00:59" />

What is the difference between background and background-color

There's a bug regarding with background and background-color

the difference of this, when using background, sometimes when your creating a webpage in CSS background: #fff // can over ride a block of Mask image("top item, text or image")) so its better to always use background-color for safe use, in your design if its individual

How do I find the CPU and RAM usage using PowerShell?

To export the output to file on a continuous basis (here every five seconds) and save to a CSV file with the Unix date as the filename:

while ($true) {
     [int]$date = get-date -Uformat %s
     $exportlocation = New-Item -type file -path "c:\$date.csv"
     Get-Counter -Counter "\Processor(_Total)\% Processor Time" | % {$_} | Out-File $exportlocation
     start-sleep -s 5
}

.NET Global exception handler in console application

You also need to handle exceptions from threads:

static void Main(string[] args) {
Application.ThreadException += MYThreadHandler;
}

private void MYThreadHandler(object sender, Threading.ThreadExceptionEventArgs e)
{
    Console.WriteLine(e.Exception.StackTrace);
}

Whoop, sorry that was for winforms, for any threads you're using in a console application you will have to enclose in a try/catch block. Background threads that encounter unhandled exceptions do not cause the application to end.

Iframe positioning

you have to use this css property,

 position:relative;

use it for your #contentframe div tag

jquery variable syntax

self and $self aren't the same. The former is the object pointed to by "this" and the latter a jQuery object whose "scope" is the object pointed to by "this". Similarly, $body isn't the body DOM element but the jQuery object whose scope is the body element.

Clear data in MySQL table with PHP?

MySQLI example where $con is the database connection variable and table name is: mytable.

mysqli_query($con,'TRUNCATE TABLE mytable');

jQuery multiple conditions within if statement

Try

if (!(i == 'InvKey' || i == 'PostDate')) {

or

if (i != 'InvKey' || i != 'PostDate') {

that says if i does not equals InvKey OR PostDate

Convert string to number field

Within Crystal, you can do it by creating a formula that uses the ToNumber function. It might be a good idea to code for the possibility that the field might include non-numeric data - like so:

If NumericText ({field}) then ToNumber ({field}) else 0

Alternatively, you might find it easier to convert the field's datatype within the query used in the report.

Match two strings in one line with grep

git grep

Here is the syntax using git grep with multiple patterns:

git grep --all-match --no-index -l -e string1 -e string2 -e string3 file

You may also combine patterns with Boolean expressions such as --and, --or and --not.

Check man git-grep for help.


--all-match When giving multiple pattern expressions, this flag is specified to limit the match to files that have lines to match all of them.

--no-index Search files in the current directory that is not managed by Git.

-l/--files-with-matches/--name-only Show only the names of files.

-e The next parameter is the pattern. Default is to use basic regexp.

Other params to consider:

--threads Number of grep worker threads to use.

-q/--quiet/--silent Do not output matched lines; exit with status 0 when there is a match.

To change the pattern type, you may also use -G/--basic-regexp (default), -F/--fixed-strings, -E/--extended-regexp, -P/--perl-regexp, -f file, and other.

Related:

For OR operation, see:

How to pick element inside iframe using document.getElementById

You need to make sure the frame is fully loaded the best way to do it is to use onload:

<iframe id="nesgt" src="" onload="custom()"></iframe>

function custom(){
    document.getElementById("nesgt").contentWindow.document;
    }

this function will run automatically when the iframe is fully loaded.

it could be done with setTimeout but we can't get the exact time of the frame load.

hope this helps someone.

Pass parameters in setInterval function

You can use an anonymous function;

setInterval(function() { funca(10,3); },500);

Set 4 Space Indent in Emacs in Text Mode

Just changing the style with c-set-style was enough for me.

Python Serial: How to use the read or readline function to read more than 1 character at a time

Serial sends data 8 bits at a time, that translates to 1 byte and 1 byte means 1 character.

You need to implement your own method that can read characters into a buffer until some sentinel is reached. The convention is to send a message like 12431\n indicating one line.

So what you need to do is to implement a buffer that will store X number of characters and as soon as you reach that \n, perform your operation on the line and proceed to read the next line into the buffer.

Note you will have to take care of buffer overflow cases i.e. when a line is received that is longer than your buffer etc...

EDIT

import serial

ser = serial.Serial(
    port='COM5',\
    baudrate=9600,\
    parity=serial.PARITY_NONE,\
    stopbits=serial.STOPBITS_ONE,\
    bytesize=serial.EIGHTBITS,\
        timeout=0)

print("connected to: " + ser.portstr)

#this will store the line
line = []

while True:
    for c in ser.read():
        line.append(c)
        if c == '\n':
            print("Line: " + ''.join(line))
            line = []
            break

ser.close()

How to change font size in Eclipse for Java text editors?

I tend to use menu Windows ? Preferences ? General ? Appearances ? Colors and Fonts ? Java Text Editors ? Change ? Apply.

What column type/length should I use for storing a Bcrypt hashed password in a Database?

I don't think that there are any neat tricks you can do storing this as you can do for example with an MD5 hash.

I think your best bet is to store it as a CHAR(60) as it is always 60 chars long

Where are include files stored - Ubuntu Linux, GCC

gcc is a rich and complex "orchestrating" program that calls many other programs to perform its duties. For the specific purpose of seeing where #include "goo" and #include <zap> will search on your system, I recommend:

$ touch a.c
$ gcc -v -E a.c
 ...
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/include
 /usr/lib/gcc/i686-apple-darwin9/4.0.1/include
 /usr/include
 /System/Library/Frameworks (framework directory)
 /Library/Frameworks (framework directory)
End of search list.
# 1 "a.c"

This is one way to see the search lists for included files, including (if any) directories into which #include "..." will look but #include <...> won't. This specific list I'm showing is actually on Mac OS X (aka Darwin) but the commands I recommend will show you the search lists (as well as interesting configuration details that I've replaced with ... here;-) on any system on which gcc runs properly.

How to UPSERT (MERGE, INSERT ... ON DUPLICATE UPDATE) in PostgreSQL?

I am trying to contribute with another solution for the single insertion problem with the pre-9.5 versions of PostgreSQL. The idea is simply to try to perform first the insertion, and in case the record is already present, to update it:

do $$
begin 
  insert into testtable(id, somedata) values(2,'Joe');
exception when unique_violation then
  update testtable set somedata = 'Joe' where id = 2;
end $$;

Note that this solution can be applied only if there are no deletions of rows of the table.

I do not know about the efficiency of this solution, but it seems to me reasonable enough.

Simple DateTime sql query

You missed single quote sign:

SELECT * 
FROM TABLENAME 
WHERE DateTime >= '12/04/2011 12:00:00 AM' AND DateTime <= '25/05/2011 3:53:04 AM'

Also, it is recommended to use ISO8601 format YYYY-MM-DDThh:mm:ss.nnn[ Z ], as this one will not depend on your server's local culture.

SELECT *
FROM TABLENAME 
WHERE 
    DateTime >= '2011-04-12T00:00:00.000' AND 
    DateTime <= '2011-05-25T03:53:04.000'

socket programming multiple client to one server

See O'Reilly "Java Cookbook", Ian Darwin - recipe 17.4 Handling Multiple Clients.

Pay attention that accept() is not thread safe, so the call is wrapped within synchronized.

64: synchronized(servSock) {
65:     clientSocket = servSock.accept();
66: }

Eclipse internal error while initializing Java tooling

check the Eclipse log (the intelligently named ".log" file in your workspace .metadata folder) and check for the complete stacktrace. In my case it was caused at method "org.eclipse.m2e.jdt.internal.MavenClasspathVariableInitializer.initialize(MavenClasspathVariableInitializer.java:30)" which lead to a never fixed "race condition during startup" bug. I would really recommend dumping Eclipse in favor of a more serious IDE; like IntelliJ or Netbeans. Using Eclipse means that you will invest 40-50% of your time trying to work around this kind of bugs, instead of being productive.

How to use data-binding with Fragment

The data binding implementation must be in the onCreateView method of the fragment, delete any data Binding that exist in your OnCreate method, your onCreateView should look like this:

public View onCreateView(LayoutInflater inflater, 
                         @Nullable ViewGroup container, 
                         @Nullable Bundle savedInstanceState) {
    MartianDataBinding binding = DataBindingUtil.inflate(
            inflater, R.layout.martian_data, container, false);
    View view = binding.getRoot();
    //here data must be an instance of the class MarsDataProvider
    binding.setMarsdata(data);
    return view;
}

Java Multithreading concept and join() method

My Comments:

When I see the output, the output is mixed with One, Two, Three which are the thread names and they run simultaneously. I am not sure when you say thread is not running by main method.

Not sure if I understood your question or not. But I m putting my answer what I could understand, hope it can help you.

1) Then you created the object, it called the constructor, in construct it has start method which started the thread and executed the contents written inside run() method.

So as you created 3 objects (3 threads - one, two, three), all 3 threads started executing simultaneously.

2) Join and Synchronization They are 2 different things, Synchronization is when there are multiple threads sharing a common resource and one thread should use that resource at a time. E.g. Threads such as DepositThread, WithdrawThread etc. do share a common object as BankObject. So while DepositThread is running, the WithdrawThread will wait if they are synchronized. wait(), notify(), notifyAll() are used for inter-thread communication. Plz google to know more.

about Join(), it is when multiple threads are running, but you join. e.g. if there are two thread t1 and t2 and in multi-thread env they run, the output would be: t1-0 t2-0 t1-1 t2-1 t1-2 t2-2

and we use t1.join(), it would be: t1-0 t1-1 t1-2 t2-0 t2-1 t2-2

This is used in realtime when sometimes you don't mix up the thread in certain conditions and one depends another to be completed (not in shared resource), so you can call the join() method.

Https to http redirect using htaccess

You can use the following rule to redirect from https to http :

 RewriteEngine On


RewriteCond %{HTTPS} ^on$
RewriteRule ^(.*)$ http://example.com/$1 [NC,L,R]

Explanation :

RewriteCond %{HTTPS} ^on$

Checks if the HTTPS is on (Request is made using https)

Then

RewriteRule ^(.*)$ http://example.com/$1 [NC,L,R]

Redirect any request (https://example.com/foo) to http://example.com/foo .

  • $1 is part of the regex in RewriteRule pattern, it contains whatever value was captured in (.+) , in this case ,it captures the full request_uri everything after the domain name.

  • [NC,L,R] are the flags, NC makes the uri case senstive, you can use both uppercase or lowercase letters in the request.

L flag tells the server to stop proccessing other rules if the currunt rule has matched, it is important to use the L flag to avoid rule confliction when you have more then on rules in a block.

R flag is used to make an external redirection.

Stack smashing detected

Stack corruptions ususally caused by buffer overflows. You can defend against them by programming defensively.

Whenever you access an array, put an assert before it to ensure the access is not out of bounds. For example:

assert(i + 1 < N);
assert(i < N);
a[i + 1] = a[i];

This makes you think about array bounds and also makes you think about adding tests to trigger them if possible. If some of these asserts can fail during normal use turn them into a regular if.

How to check if activity is in foreground or in visible background?

If you use finish() just to avoid new app to starts in the stack (task) of you app, you can use Intent.FLAG_ACTIVITY_NEW_TASK flag, when starting new application and do not call finish() at all. According to the documentation, this is the flag to be used to implement a "launcher" style behavior.

// just add this line before you start an activity
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);

Git diff says subproject is dirty

I ended up removing the submodule directory and initializing it once again

cd my-submodule
git push
cd ../
rm -rf my-submodule
git submodule init
git submodule update

How to generate Javadoc from command line

Let's say you have the following directory structure where you want to generate javadocs on file1.java and file2.java (package com.test), with the javadocs being placed in C:\javadoc\test:

C:\
|
+--javadoc\
|  |
|  +--test\
|
+--projects\
   |
   +--com\
      |
      +--test\
         |
         +--file1.java
         +--file2.java

In the command terminal, navigate to the root of your package: C:\projects. If you just want to generate the standard javadocs on all the java files inside the project, run the following command (for multiple packages, separate the package names by spaces):

C:\projects> javadoc -d [path to javadoc destination directory] [package name]

C:\projects> javadoc -d C:\javadoc\test com.test

If you want to run javadocs from elsewhere, you'll need to specify the sourcepath. For example, if you were to run javadocs in in C:\, you would modify the command as such:

C:\> javadoc -d [path to javadoc destination directory] -sourcepath [path to package directory] [package name]

C:\> javadoc -d C:\javadoc\test -sourcepath C:\projects com.test

If you want to run javadocs on only selected .java files, then add the source filenames separated by spaces (you can use an asterisk (*) for a wildcard). Make sure to include the path to the files:

C:\> javadoc -d [path to javadoc destination directory] [source filenames]

C:\> javadoc -d C:\javadoc\test C:\projects\com\test\file1.java

More information/scenarios can be found here.

Angular 2 / 4 / 5 not working in IE11

  1. Uncomment IE section in the src/polyfill.js,

    /** IE10 and IE11 requires the following for NgClass support on SVG elements*/

    import 'classlist.js';

  2. If any build error for missing package then,

    npm install classlist.js --save-exact

  3. Make sure to include below line to set the default IE document mode. Other wise it will open in version 7

 <meta http-equiv="X-UA-Compatible" content="IE=edge" />

SQL/mysql - Select distinct/UNIQUE but return all columns?

From the phrasing of your question, I understand that you want to select the distinct values for a given field and for each such value to have all the other column values in the same row listed. Most DBMSs will not allow this with neither DISTINCT nor GROUP BY, because the result is not determined.

Think of it like this: if your field1 occurs more than once, what value of field2 will be listed (given that you have the same value for field1 in two rows but two distinct values of field2 in those two rows).

You can however use aggregate functions (explicitely for every field that you want to be shown) and using a GROUP BY instead of DISTINCT:

SELECT field1, MAX(field2), COUNT(field3), SUM(field4), .... FROM table GROUP BY field1

What does -Xmn jvm option stands for

-Xmn : the size of the heap for the young generation Young generation represents all the objects which have a short life of time. Young generation objects are in a specific location into the heap, where the garbage collector will pass often. All new objects are created into the young generation region (called "eden"). When an object survive is still "alive" after more than 2-3 gc cleaning, then it will be swap has an "old generation" : they are "survivor" .

Good size is 33%

Source

Use URI builder in Android or create URL with variables

Excellent answer from above turned into a simple utility method.

private Uri buildURI(String url, Map<String, String> params) {

    // build url with parameters.
    Uri.Builder builder = Uri.parse(url).buildUpon();
    for (Map.Entry<String, String> entry : params.entrySet()) {
        builder.appendQueryParameter(entry.getKey(), entry.getValue());
    }

    return builder.build();
}

Is it correct to use alt tag for an anchor link?

"title" is widely implemented in browsers. Try:

<a href="#" title="hello">asf</a>

Using os.walk() to recursively traverse directories in Python

Would be the best way

def traverse_dir_recur(dir):
    import os
    l = os.listdir(dir)
    for d in l:
        if os.path.isdir(dir + d):
            traverse_dir_recur(dir+  d +"/")
        else:
            print(dir + d)

How to execute my SQL query in CodeIgniter

If the databases share server, have a login that has priveleges to both of the databases, and simply have a query run similiar to:

$query = $this->db->query("
SELECT t1.*, t2.id
FROM `database1`.`table1` AS t1, `database2`.`table2` AS t2
");

Otherwise I think you might have to run the 2 queries separately and fix the logic afterwards.

pyplot axes labels for subplots

One simple way using subplots:

import matplotlib.pyplot as plt

fig, axes = plt.subplots(3, 4, sharex=True, sharey=True)
# add a big axes, hide frame
fig.add_subplot(111, frameon=False)
# hide tick and tick label of the big axes
plt.tick_params(labelcolor='none', top=False, bottom=False, left=False, right=False)
plt.grid(False)
plt.xlabel("common X")
plt.ylabel("common Y")

File uploading with Express 4.0: req.files undefined

1) Make sure that your file is really sent from the client side. For example you can check it in Chrome Console: screenshot

2) Here is the basic example of NodeJS backend:

const express = require('express');
const fileUpload = require('express-fileupload');
const app = express();

app.use(fileUpload()); // Don't forget this line!

app.post('/upload', function(req, res) {
   console.log(req.files);
   res.send('UPLOADED!!!');
});