Programs & Examples On #Xmldataset

How can I pass selected row to commandLink inside dataTable or ui:repeat?

In JSF 1.2 this was done by <f:setPropertyActionListener> (within the command component). In JSF 2.0 (EL 2.2 to be precise, thanks to BalusC) it's possible to do it like this: action="${filterList.insert(f.id)}

pip install failing with: OSError: [Errno 13] Permission denied on directory

You are trying to install a package on the system-wide path without having the permission to do so.

  1. In general, you can use sudo to temporarily obtain superuser permissions at your responsibility in order to install the package on the system-wide path:

     sudo pip install -r requirements.txt
    

    Find more about sudo here.

    Actually, this is a bad idea and there's no good use case for it, see @wim's comment.

  2. If you don't want to make system-wide changes, you can install the package on your per-user path using the --user flag.

    All it takes is:

     pip install --user runloop requirements.txt
    
  3. Finally, for even finer grained control, you can also use a virtualenv, which might be the superior solution for a development environment, especially if you are working on multiple projects and want to keep track of each one's dependencies.

    After activating your virtualenv with

    $ my-virtualenv/bin/activate

    the following command will install the package inside the virtualenv (and not on the system-wide path):

    pip install -r requirements.txt

Angular2 - Radio Button Binding

On Radio button change get the value of the respective buttons with these lines

<label class="radio-inline">
<input class="form-check-input" type="radio" [(ngModel)]="dog" name="cat"  checked (change)="onItemChange($event)" value="Dog" />Dog</label>
<label class="radio-inline">
<input class="form-check-input" type="radio" [(ngModel)]="cat" name="cat"   (change)="onItemChange($event)" value="Cat"  />Cat</label>

https://stackblitz.com/edit/angular-jpo2dm?embed=1&file=src/app/app.component.html

Styling Form with Label above Inputs

You could try something like

<form name="message" method="post">
    <section>
    <div>
      <label for="name">Name</label>
      <input id="name" type="text" value="" name="name">
    </div>
    <div>
      <label for="email">Email</label>
      <input id="email" type="text" value="" name="email">
    </div>
    </section>
    <section>
    <div>
      <label for="subject">Subject</label>
      <input id="subject" type="text" value="" name="subject">
    </div>
    <div class="full">
      <label for="message">Message</label>
      <input id="message" type="text" value="" name="message">
    </div>
    </section>
</form>

and then css it like

form { width: 400px; }
form section div { float: left; }
form section div.full { clear: both; }
form section div label { display: block; }

Telegram Bot - how to get a group chat id?

You can retrieve the group ID the same way. It appears in the message body as message.chat.id and it's usually a negative number, where normal chats are positive.

Group IDs and Chat IDs can only be retrieved from a received message, there are no calls available to retrieve active groups etc. You have to remember the group ID when you receive the message and store it in cache or something similar.

Hyphen, underscore, or camelCase as word delimiter in URIs?

In general, it's not going to have enough of an impact to worry about, particularly since it's an intranet app and not a general-use Internet app. In particular, since it's intranet, SEO isn't a concern, since your intranet shouldn't be accessible to search engines. (and if it is, it isn't an intranet app).

And any framework worth it's salt either already has a default way to do this, or is fairly easy to change how it deals with multi-word URL components, so I wouldn't worry about it too much.

That said, here's how I see the various options:

Hyphen

  • The biggest danger for hyphens is that the same character (typically) is also used for subtraction and numerical negation (ie. minus or negative).
  • Hyphens feel awkward in URL components. They seem to only make sense at the end of a URL to separate words in the title of an article. Or, for example, the title of a Stack Overflow question that is added to the end of a URL for SEO and user-clarity purposes.

Underscore

  • Again, they feel wrong in URL components. They break up the flow (and beauty/simplicity) of a URL, since they essentially add a big, heavy apparent space in the middle of a clean, flowing URL.
  • They tend to blend in with underlines. If you expect your users to copy-paste your URLs into MS Word or other similar text-editing programs, or anywhere else that might pick up on a URL and style it with an underline (like links traditionally are), then you might want to avoid underscores as word separators. Particularly when printed, an underlined URL with underscores tends to look like it has spaces in it instead of underscores.

CamelCase

  • By far my favorite, since it makes the URLs seem to flow better and doesn't have any of the faults that the previous two options do.
  • Can be slightly harder to read for people that have a hard time differentiating upper-case from lower-case, but this shouldn't be much of an issue in a URL, because most "words" should be URL components and separated by a / anyways. If you find that you have a URL component that is more than 2 "words" long, you should probably try to find a better name for that concept.
  • It does have a possible issue with case sensitivity, but most platforms can be adjusted to be either case-sensitive or case-insensitive. Any it's only really an issue for 2 cases: a.) humans typing the URL in, and b.) Programmers (since we are not human) typing the URL in. Typos are always a problem, regardless of case sensitivity, so this is no different that all one case.

Android Studio with Google Play Services

  1. Go to File -> Project Structure
  2. Select 'Project Settings'
  3. Select 'Dependencies' Tab
  4. Click '+' and select '1.Library Dependencies'
  5. Search for : com.google.android.gms:play-services
  6. Select the latest version and click 'OK'

Voila! No need to fight with Gradle :)

Foreign key constraint may cause cycles or multiple cascade paths?

A typical situation with multiple cascasing paths will be this: A master table with two details, let's say "Master" and "Detail1" and "Detail2". Both details are cascade delete. So far no problems. But what if both details have a one-to-many-relation with some other table (say "SomeOtherTable"). SomeOtherTable has a Detail1ID-column AND a Detail2ID-column.

Master { ID, masterfields }

Detail1 { ID, MasterID, detail1fields }

Detail2 { ID, MasterID, detail2fields }

SomeOtherTable {ID, Detail1ID, Detail2ID, someothertablefields }

In other words: some of the records in SomeOtherTable are linked with Detail1-records and some of the records in SomeOtherTable are linked with Detail2 records. Even if it is guaranteed that SomeOtherTable-records never belong to both Details, it is now impossible to make SomeOhterTable's records cascade delete for both details, because there are multiple cascading paths from Master to SomeOtherTable (one via Detail1 and one via Detail2). Now you may already have understood this. Here is a possible solution:

Master { ID, masterfields }

DetailMain { ID, MasterID }

Detail1 { DetailMainID, detail1fields }

Detail2 { DetailMainID, detail2fields }

SomeOtherTable {ID, DetailMainID, someothertablefields }

All ID fields are key-fields and auto-increment. The crux lies in the DetailMainId fields of the Detail tables. These fields are both key and referential contraint. It is now possible to cascade delete everything by only deleting master-records. The downside is that for each detail1-record AND for each detail2 record, there must also be a DetailMain-record (which is actually created first to get the correct and unique id).

Math constant PI value in C

anyway you have not a unlimited accuracy so C define a constant in this way:

#define PI 3.14159265358979323846

import math.h to use this

ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

This typed error-message also shows while an if-statement comparison is done where there is an array and for example a bool or int. See for example:

... code snippet ...

if dataset == bool:
    ....

... code snippet ...

This clause has dataset as array and bool is euhm the "open door"... True or False.

In case the function is wrapped within a try-statement you will receive with except Exception as error: the message without its error-type:

The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

How can I debug a HTTP POST in Chrome?

You can filter for HTTP POST requests with the Chrome DevTools. Just do the following:

  1. Open Chrome DevTools (Cmd+Opt+I on Mac, Ctrl+Shift+I or F12 on Windows) and click on the "Network" tab
  2. Click on the "Filter" icon
  3. Enter your filter method: method:POST
  4. Select the request you want to debug
  5. View the details of the request you want to debug

Screenshot

Chrome DevTools

Tested with Chrome Version 53.

Undefined reference to vtable

I tried all the detailed steps by JaMIT and still got stumped by this error. After a good amount of head-banging, I figured it out. I was careless. You should be able to reproduce this painful-to-look-at error w/ the following sample code.

[jaswantp@jaswant-arch build]$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /build/gcc/src/gcc/configure --prefix=/usr --libdir=/usr/lib --libexecdir=/usr/lib --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=https://bugs.archlinux.org/ --enable-languages=c,c++,ada,fortran,go,lto,objc,obj-c++,d --with-isl --with-linker-hash-style=gnu --with-system-zlib --enable-__cxa_atexit --enable-cet=auto --enable-checking=release --enable-clocale=gnu --enable-default-pie --enable-default-ssp --enable-gnu-indirect-function --enable-gnu-unique-object --enable-install-libiberty --enable-linker-build-id --enable-lto --enable-multilib --enable-plugin --enable-shared --enable-threads=posix --disable-libssp --disable-libstdcxx-pch --disable-libunwind-exceptions --disable-werror gdc_include_dir=/usr/include/dlang/gdc
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 10.2.0 (GCC) 

// CelesetialBody.h
class CelestialBody{
public:
    virtual void Print();
protected:
    CelestialBody();
    virtual ~CelestialBody();
};
// CelestialBody.cpp
#include "CelestialBody.h"

CelestialBody::CelestialBody() {}

CelestialBody::~CelestialBody() = default;

void CelestialBody::Print() {}
// Planet.h
#include "CelestialBody.h"

class Planet : public CelestialBody
{
public:
    void Print() override;
protected:
    Planet();
    ~Planet() override;
};
// Planet.cpp
#include "Planet.h"

Planet::Planet() {}
Planet::~Planet() {}

void Print() {} // Deliberately forgot to prefix `Planet::`
# CMakeLists.txt
cmake_minimum_required(VERSION 3.12)
project (space_engine)
add_library (CelestialBody SHARED CelestialBody.cpp)
add_library (Planet SHARED Planet.cpp)
target_include_directories (CelestialBody PRIVATE ${CMAKE_CURRENT_LIST_DIR})  
target_include_directories (Planet PRIVATE ${CMAKE_CURRENT_LIST_DIR})    
target_link_libraries (Planet PUBLIC CelestialBody)

# hardened linker flags to catch undefined symbols
target_link_options(Planet 
    PRIVATE 
    -Wl,--as-needed
    -Wl,--no-undefined
)

And we get our favourite error.

$ mkdir build
$ cd build
$ cmake ..
$ make
[ 50%] Built target CelestialBody
Scanning dependencies of target Planet
[ 75%] Building CXX object CMakeFiles/Planet.dir/Planet.cpp.o
[100%] Linking CXX shared library libPlanet.so
/usr/bin/ld: CMakeFiles/Planet.dir/Planet.cpp.o: in function `Planet::Planet()':
Planet.cpp:(.text+0x1b): undefined reference to `vtable for Planet'
/usr/bin/ld: CMakeFiles/Planet.dir/Planet.cpp.o: in function `Planet::~Planet()':
Planet.cpp:(.text+0x3d): undefined reference to `vtable for Planet'
collect2: error: ld returned 1 exit status
make[2]: *** [CMakeFiles/Planet.dir/build.make:104: libPlanet.so] Error 1
make[1]: *** [CMakeFiles/Makefile2:97: CMakeFiles/Planet.dir/all] Error 2
make: *** [Makefile:103: all] Error 2

What I've done in Planet.cpp should of course be resolved with this tip

  1. Look at your class definition. Find the first non-inline virtual function that is not pure virtual (not "= 0") and whose definition you provide (not "= default").

from JaMIT's answer. If there is anyone else who tried all the above and nothing worked, maybe you too, like me, carelessly forgot to prefix <ClassName>:: to one or more member functions.

Either I need to get my eyes checked or I need to get some sleep.

Missing Maven dependencies in Eclipse project

From my end, I have tried all these and none of them worked. The most probable problem with this is that you have added more than one dependency, hence it is mandatory to wrap them in a <dependencies> </dependencies> tag. Hope it helps!

How to exit git log or git diff

I wanted to give some kudos to the comment that mentioned CTRL + Z as an option. At the end of the day, it's going to depend on what system that you have Git installed on and what program is configured to open text files (e.g. less vs. vim). CTRL + Z works for vim on Windows.

If you're using Git in a Windows environment, there are some quirks. Just helps to know what they are. (i.e. Notepad vs. Nano, etc.).

Create SQL script that create database and tables

Yes, you can add as many SQL statements into a single script as you wish. Just one thing to note: the order matters. You can't INSERT into a table until you CREATE it; you can't set a foreign key until the primary key is inserted.

Swift: Reload a View Controller

You shouldn't call viewDidLoad method manually, Instead if you want to reload any data or any UI, you can use this:

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

    let myButton = UIButton()

    // When user touch myButton, we're going to call loadData method
    myButton.addTarget(self, action: #selector(self.loadData), forControlEvents: .TouchUpInside)

    // Load the data
    self.loadData();
}

func loadData() {
    // code to load data from network, and refresh the interface
    tableView.reloadData()
}

Whenever you want to reload the data and refresh the interface, you can call self.loadData()

How to run python script in webpage

As others have pointed out, there are many web frameworks for Python.

But, seeing as you are just getting started with Python, a simple CGI script might be more appropriate:

  1. Rename your script to index.cgi. You also need to execute chmod +x index.cgi to give it execution privileges.

  2. Add these 2 lines in the beginning of the file:

#!/usr/bin/python   
print('Content-type: text/html\r\n\r')

After this the Python code should run just like in terminal, except the output goes to the browser. When you get that working, you can use the cgi module to get data back from the browser.

Note: this assumes that your webserver is running Linux. For Windows, #!/Python26/python might work instead.

Page scroll when soft keyboard popped up

In your Manifest define windowSoftInputMode property:

<activity android:name=".MyActivity"
          android:windowSoftInputMode="adjustNothing">

Android - setOnClickListener vs OnClickListener vs View.OnClickListener

Imagine that we have 3 buttons for example

public class MainActivity extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);


        // Capture our button from layout
        Button button = (Button)findViewById(R.id.corky);
        Button button2 = (Button)findViewById(R.id.corky2);
        Button button3 = (Button)findViewById(R.id.corky3);
        // Register the onClick listener with the implementation above
        button.setOnClickListener(mCorkyListener);
        button2.setOnClickListener(mCorkyListener);
        button3.setOnClickListener(mCorkyListener);

    }

    // Create an anonymous implementation of OnClickListener
    private View.OnClickListener mCorkyListener = new View.OnClickListener() {
        public void onClick(View v) {
            // do something when the button is clicked 
            // Yes we will handle click here but which button clicked??? We don't know

        }
    };

}

So what we will do?

public class MainActivity extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);


        // Capture our button from layout
        Button button = (Button)findViewById(R.id.corky);
        Button button2 = (Button)findViewById(R.id.corky2);
        Button button3 = (Button)findViewById(R.id.corky3);
        // Register the onClick listener with the implementation above
        button.setOnClickListener(mCorkyListener);
        button2.setOnClickListener(mCorkyListener);
        button3.setOnClickListener(mCorkyListener);

    }

    // Create an anonymous implementation of OnClickListener
    private View.OnClickListener mCorkyListener = new View.OnClickListener() {
        public void onClick(View v) {
            // do something when the button is clicked
            // Yes we will handle click here but which button clicked??? We don't know

            // So we will make
            switch (v.getId() /*to get clicked view id**/) {
                case R.id.corky:

                    // do something when the corky is clicked

                    break;
                case R.id.corky2:

                    // do something when the corky2 is clicked

                    break;
                case R.id.corky3:

                    // do something when the corky3 is clicked

                    break;
                default:
                    break;
            }
        }
    };

}

Or we can do this:

public class MainActivity extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);


        // Capture our button from layout
        Button button = (Button)findViewById(R.id.corky);
        Button button2 = (Button)findViewById(R.id.corky2);
        Button button3 = (Button)findViewById(R.id.corky3);
        // Register the onClick listener with the implementation above
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do something when the corky is clicked
            }
        });
        button2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do something when the corky2 is clicked
            }
        });
        button3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // do something when the corky3 is clicked
            }
        });

    }

}

Or we can implement View.OnClickListener and i think it's the best way:

public class MainActivity extends ActionBarActivity implements View.OnClickListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);


        // Capture our button from layout
        Button button = (Button)findViewById(R.id.corky);
        Button button2 = (Button)findViewById(R.id.corky2);
        Button button3 = (Button)findViewById(R.id.corky3);
        // Register the onClick listener with the implementation above
        button.setOnClickListener(this);
        button2.setOnClickListener(this);
        button3.setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {
        // do something when the button is clicked
        // Yes we will handle click here but which button clicked??? We don't know

        // So we will make
        switch (v.getId() /*to get clicked view id**/) {
            case R.id.corky:

                // do something when the corky is clicked

                break;
            case R.id.corky2:

                // do something when the corky2 is clicked

                break;
            case R.id.corky3:

                // do something when the corky3 is clicked

                break;
            default:
                break;
        }
    }
}

Finally there is no real differences here Just "Way better than the other"

what happens when you type in a URL in browser

First the computer looks up the destination host. If it exists in local DNS cache, it uses that information. Otherwise, DNS querying is performed until the IP address is found.

Then, your browser opens a TCP connection to the destination host and sends the request according to HTTP 1.1 (or might use HTTP 1.0, but normal browsers don't do it any more).

The server looks up the required resource (if it exists) and responds using HTTP protocol, sends the data to the client (=your browser)

The browser then uses HTML parser to re-create document structure which is later presented to you on screen. If it finds references to external resources, such as pictures, css files, javascript files, these are is delivered the same way as the HTML document itself.

Android WebView progress bar

This is how I did it with Kotlin to show progress with percentage.

My fragment layout.

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
         xmlns:tools="http://schemas.android.com/tools"
         android:layout_width="match_parent"
         android:layout_height="match_parent">

<WebView
    android:id="@+id/webView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

<ProgressBar
    android:layout_marginLeft="32dp"
    android:layout_marginRight="32dp"
    style="?android:attr/progressBarStyleHorizontal"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:id="@+id/progressBar"/>
</FrameLayout>

My kotlin fragment in onViewCreated

    progressBar.max = 100;
    webView.webChromeClient = object : WebChromeClient() {
        override fun onProgressChanged(view: WebView?, newProgress: Int) {
            super.onProgressChanged(view, newProgress)
            progressBar.progress = newProgress;
        }
    }

    webView!!.webViewClient = object : WebViewClient() {

        override fun onPageStarted(view: WebView?, url: String?, favicon: Bitmap?) {
            progressBar.visibility = View.VISIBLE
            progressBar.progress = 0;
            super.onPageStarted(view, url, favicon)
        }

        override fun shouldOverrideUrlLoading(view: WebView?, url: String?): Boolean {
            view?.loadUrl(url)
            return true
        }

        override fun shouldOverrideUrlLoading(
            view: WebView?,
            request: WebResourceRequest?): Boolean {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                view?.loadUrl(request?.url.toString())
            }
            return true
        }

        override fun onPageFinished(view: WebView?, url: String?) {
            super.onPageFinished(view, url)
            progressBar.visibility = View.GONE
        }
    }

    webView.loadUrl(url)

C# create simple xml file

You could use XDocument:

new XDocument(
    new XElement("root", 
        new XElement("someNode", "someValue")    
    )
)
.Save("foo.xml");

If the file you want to create is very big and cannot fit into memory you might use XmlWriter.

CSS border less than 1px

It's impossible to draw a line on screen that's thinner than one pixel. Try using a more subtle color for the border instead.

Private class declaration

private makes the class accessible only to the class in which it is declared. If we make entire class private no one from outside can access the class and makes it useless.

Inner class can be made private because the outer class can access inner class where as it is not the case with if you make outer class private.

jQuery: Count number of list elements?

var listItems = $("#myList").children();

var count = listItems.length;

Of course you can condense this with

var count = $("#myList").children().length;

For more help with jQuery, http://docs.jquery.com/Main_Page is a good place to start.

How to correctly use Html.ActionLink with ASP.NET MVC 4 Areas

Just to add up my bit:
Remember, you're gonna need to have at least 2 areas in your MVC application to get the routeValues: { area="" } working; otherwise the area value will be used as a query-string parameter and you link will look like this: /?area=

If you don't have at least 2 areas, you can fix this behavior by:
1. editing the default route in RouteConfig.cs like this:

routes.MapRoute(
    name: "Default",
    url: "{controller}/{action}/{id}",
    defaults: new { area = "", controller = "Home", action = "Index", id = UrlParameter.Optional }
);

OR
2. Adding a dummy area to your MVC project.

Django: Redirect to previous page after login

You can also do this

<input type="hidden" name="text" value="{% url 'dashboard' %}" />

bootstrap 3 wrap text content within div for horizontal alignment

Add the following style to your h3 elements:

word-wrap: break-word;

This will cause the long URLs in them to wrap. The default setting for word-wrap is normal, which will wrap only at a limited set of split tokens (e.g. whitespaces, hyphens), which are not present in a URL.

How to get the number of characters in a string

There are several ways to get a string length:

package main

import (
    "bytes"
    "fmt"
    "strings"
    "unicode/utf8"
)

func main() {
    b := "?????"
    len1 := len([]rune(b))
    len2 := bytes.Count([]byte(b), nil) -1
    len3 := strings.Count(b, "") - 1
    len4 := utf8.RuneCountInString(b)
    fmt.Println(len1)
    fmt.Println(len2)
    fmt.Println(len3)
    fmt.Println(len4)

}

How to get all elements which name starts with some string?

You can try using jQuery with the Attribute Contains Prefix Selector.

$('[id|=q1_]')

Haven't tested it though.

Set database timeout in Entity Framework

I extended Ronnie's answer with a fluent implementation so you can use it like so:

dm.Context.SetCommandTimeout(120).Database.SqlQuery...

public static class EF
{
    public static DbContext SetCommandTimeout(this DbContext db, TimeSpan? timeout)
    {
        ((IObjectContextAdapter)db).ObjectContext.CommandTimeout = timeout.HasValue ? (int?) timeout.Value.TotalSeconds : null;

        return db;
    }

    public static DbContext SetCommandTimeout(this DbContext db, int seconds)
    {
        return db.SetCommandTimeout(TimeSpan.FromSeconds(seconds));
    } 
}

Android webview launches browser when calling loadurl

I was facing the same problem and I found the solution Android's official Documentation about WebView

Here is my onCreateView() method and here i used two methods to open the urls

Method 1 is opening url in Browser and

Method 2 is opening url in your desired WebView.
And I am using Method 2 for my Application and this is my code:

public class MainActivity extends Activity {
   private WebView myWebView;

     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

      View rootView = inflater.inflate(R.layout.fragment_webpage_detail, container, false);

      // Show the dummy content as text in a TextView.
      if (mItem != null) {

         /* Method : 1
          This following line is working fine BUT when we click the menu item then it opens the URL in BROWSER not in WebView */
         //((WebView)   rootView.findViewById(R.id.detail_area)).loadUrl(mItem.url);

        // Method : 2
        myWebView = (WebView) rootView.findViewById(R.id.detail_area); // get your WebView form your xml file
        myWebView.setWebViewClient(new WebViewClient()); // set the WebViewClient
        myWebView.loadUrl(mItem.url); // Load your desired url
    }

    return rootView;
}                                                                                               }

Display a angular variable in my html page

In your template, you have access to all the variables that are members of the current $scope. So, tobedone should be $scope.tobedone, and then you can display it with {{tobedone}}, or [[tobedone]] in your case.

PHP parse/syntax errors; and how to solve them

Unexpected '?'

If you are trying to use the null coalescing operator ?? in a version of PHP prior to PHP 7 you will get this error.

<?= $a ?? 2; // works in PHP 7+
<?= (!empty($a)) ? $a : 2; // All versions of PHP

Unexpected '?', expecting variable

A similar error can occur for nullable types, as in:

function add(?int $sum): ?int {

Which again indicates an outdated PHP version being used (either the CLI version php -v or the webserver bound one phpinfo();).

Installing a pip package from within a Jupyter Notebook not working

In IPython (jupyter) 7.3 and later, there is a magic %pip and %conda command that will install into the current kernel (rather than into the instance of Python that launched the notebook).

%pip install geocoder

In earlier versions, you need to use sys to fix the problem like in the answer by FlyingZebra1

import sys
!{sys.executable} -m pip install geocoder

Put search icon near textbox using bootstrap

Here are three different ways to do it:

screenshot

Here's a working Demo in Fiddle Of All Three

Validation:

You can use native bootstrap validation states (No Custom CSS!):

<div class="form-group has-feedback">
    <label class="control-label" for="inputSuccess2">Name</label>
    <input type="text" class="form-control" id="inputSuccess2"/>
    <span class="glyphicon glyphicon-search form-control-feedback"></span>
</div>

For a full discussion, see my answer to Add a Bootstrap Glyphicon to Input Box

Input Group:

You can use the .input-group class like this:

<div class="input-group">
    <input type="text" class="form-control"/>
    <span class="input-group-addon">
        <i class="fa fa-search"></i>
    </span>
</div>

For a full discussion, see my answer to adding Twitter Bootstrap icon to Input box

Unstyled Input Group:

You can still use .input-group for positioning but just override the default styling to make the two elements appear separate.

Use a normal input group but add the class input-group-unstyled:

<div class="input-group input-group-unstyled">
    <input type="text" class="form-control" />
    <span class="input-group-addon">
        <i class="fa fa-search"></i>
    </span>
</div>

Then change the styling with the following css:

.input-group.input-group-unstyled input.form-control {
    -webkit-border-radius: 4px;
       -moz-border-radius: 4px;
            border-radius: 4px;
}
.input-group-unstyled .input-group-addon {
    border-radius: 4px;
    border: 0px;
    background-color: transparent;
}

Also, these solutions work for any input size

How to change the background-color of jumbrotron?

.jumbotron {
background-color:black !important; 

}

Add this one line code in .css file, worked for me!

Difference between static class and singleton pattern?

static classes usually are used for libraries, singletons are used if I need only one instance of a particular class. From the point of view of memory there are some differences though: usually in the heap there are allocated only objects, the only methods allocated are methods that are current running. a static class has all methods static too and that will be in the heap from begin, so in general the static class consume more memory.

Differences between git pull origin master & git pull origin/master

git pull = git fetch + git merge origin/branch

git pull and git pull origin branch only differ in that the latter will only "update" origin/branch and not all origin/* as git pull does.

git pull origin/branch will just not work because it's trying to do a git fetch origin/branch which is invalid.

Question related: git fetch + git merge origin/master vs git pull origin/master

Converting Stream to String and back...what are we missing?

I wrote a useful method to call any action that takes a StreamWriter and write it out to a string instead. The method is like this;

static void SendStreamToString(Action<StreamWriter> action, out string destination)
{
    using (var stream = new MemoryStream())
    using (var writer = new StreamWriter(stream, Encoding.Unicode))
    {
        action(writer);
        writer.Flush();
        stream.Position = 0;
        destination = Encoding.Unicode.GetString(stream.GetBuffer(), 0, (int)stream.Length);
    }
}

And you can use it like this;

string myString;

SendStreamToString(writer =>
{
    var ints = new List<int> {1, 2, 3};
    writer.WriteLine("My ints");
    foreach (var integer in ints)
    {
        writer.WriteLine(integer);
    }
}, out myString);

I know this can be done much easier with a StringBuilder, the point is that you can call any method that takes a StreamWriter.

Unable to access JSON property with "-" dash

jsonObj.profile-id is a subtraction expression (i.e. jsonObj.profile - id).

To access a key that contains characters that cannot appear in an identifier, use brackets:

jsonObj["profile-id"]

What is the equivalent of Java's final in C#?

As mentioned, sealed is an equivalent of final for methods and classes.

As for the rest, it is complicated.

  • For static final fields, static readonly is the closest thing possible. It allows you to initialize the static field in a static constructor, which is fairly similar to static initializer in Java. This applies both to constants (primitives and immutable objects) and constant references to mutable objects.

    The const modifier is fairly similar for constants, but you can't set them in a static constructor.

  • On a field that shouldn't be reassigned once it leaves the constructor, readonly can be used. It is not equal though - final requires exactly one assignment even in constructor or initializer.

  • There is no C# equivalent for a final local variable that I know of. If you are wondering why would anyone need it: You can declare a variable prior to an if-else, switch-case or so. By declaring it final, you enforce that it is assigned at most once.

    Java local variables in general are required to be assigned at least once before they are read. Unless the branch jumps out before value read, a final variable is assigned exactly once. All of this is checked compile-time. This requires well behaved code with less margin for an error.

Summed up, C# has no direct equivalent of final. While Java lacks some nice features of C#, it is refreshing for me as mostly a Java programmer to see where C# fails to deliver an equivalent.

Add JVM options in Tomcat

if you want to set jvm args on eclipse you can use below:

see below two links to accomplish it:

  1. eclipse setting to pass jvm args to java
  2. eclipse setting to pass jvm args to java and adding to run config on eclipse

And for Tomcat you can create a setenv.bat file in bin folder of Tomcat and add below lines to it :

echo "hello im starting setenv"
set CATALINA_OPTS=-DNLP.home=${NLP.home} -Dhostname=${hostname}

Virtualbox shared folder permissions

This also works

sudo usermod -aG <group> <user>

Then restart vm

Single controller with multiple GET methods in ASP.NET Web API

Have you tried switching over to WebInvokeAttribute and setting the Method to "GET"?

I believe I had a similar problem and switched to explicitly telling which Method (GET/PUT/POST/DELETE) is expected on most, if not all, my methods.

public class SomeController : ApiController
{
    [WebInvoke(UriTemplate = "{itemSource}/Items"), Method="GET"]
    public SomeValue GetItems(CustomParam parameter) { ... }

    [WebInvoke(UriTemplate = "{itemSource}/Items/{parent}", Method = "GET")]
    public SomeValue GetChildItems(CustomParam parameter, SomeObject parent) { ... }
}

The WebGet should handle it but I've seen it have some issues with multiple Get much less multiple Get of the same return type.

[Edit: none of this is valid with the sunset of WCF WebAPI and the migration to ASP.Net WebAPI on the MVC stack]

Use Toast inside Fragment

You are not calling show() on the Toast you are creating with makeText().

How can I avoid Java code in JSP files, using JSP 2?

The use of scriptlets (those <% %> things) in JSP is indeed highly discouraged since the birth of taglibs (like JSTL) and EL (Expression Language, those ${} things) way back in 2001.

The major disadvantages of scriptlets are:

  1. Reusability: you can't reuse scriptlets.
  2. Replaceability: you can't make scriptlets abstract.
  3. OO-ability: you can't make use of inheritance/composition.
  4. Debuggability: if scriptlet throws an exception halfway, all you get is a blank page.
  5. Testability: scriptlets are not unit-testable.
  6. Maintainability: per saldo more time is needed to maintain mingled/cluttered/duplicated code logic.

Sun Oracle itself also recommends in the JSP coding conventions to avoid use of scriptlets whenever the same functionality is possible by (tag) classes. Here are several cites of relevance:

From JSP 1.2 Specification, it is highly recommended that the JSP Standard Tag Library (JSTL) be used in your web application to help reduce the need for JSP scriptlets in your pages. Pages that use JSTL are, in general, easier to read and maintain.

...

Where possible, avoid JSP scriptlets whenever tag libraries provide equivalent functionality. This makes pages easier to read and maintain, helps to separate business logic from presentation logic, and will make your pages easier to evolve into JSP 2.0-style pages (JSP 2.0 Specification supports but de-emphasizes the use of scriptlets).

...

In the spirit of adopting the model-view-controller (MVC) design pattern to reduce coupling between the presentation tier from the business logic, JSP scriptlets should not be used for writing business logic. Rather, JSP scriptlets are used if necessary to transform data (also called "value objects") returned from processing the client's requests into a proper client-ready format. Even then, this would be better done with a front controller servlet or a custom tag.


How to replace scriptlets entirely depends on the sole purpose of the code/logic. More than often this code is to be placed in a fullworthy Java class:

  • If you want to invoke the same Java code on every request, less-or-more regardless of the requested page, e.g. checking if a user is logged in, then implement a filter and write code accordingly in doFilter() method. E.g.:

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException {
        if (((HttpServletRequest) request).getSession().getAttribute("user") == null) {
            ((HttpServletResponse) response).sendRedirect("login"); // Not logged in, redirect to login page.
        } else {
            chain.doFilter(request, response); // Logged in, just continue request.
        }
    }
    

    When mapped on an appropriate <url-pattern> covering the JSP pages of interest, then you don't need to copypaste the same piece of code overall JSP pages.


  • If you want to invoke some Java code to preprocess a request, e.g. preloading some list from a database to display in some table, if necessary based on some query parameters, then implement a servlet and write code accordingly in doGet() method. E.g.:

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        try {
            List<Product> products = productService.list(); // Obtain all products.
            request.setAttribute("products", products); // Store products in request scope.
            request.getRequestDispatcher("/WEB-INF/products.jsp").forward(request, response); // Forward to JSP page to display them in a HTML table.
        } catch (SQLException e) {
            throw new ServletException("Retrieving products failed!", e);
        }
    }
    

    This way dealing with exceptions is easier. The DB is not accessed in the midst of JSP rendering, but far before the JSP is been displayed. You still have the possibility to change the response whenever the DB access throws an exception. In the above example, the default error 500 page will be displayed which you can anyway customize by an <error-page> in web.xml.


  • If you want to invoke some Java code to postprocess a request, e.g. processing a form submit, then implement a servlet and write code accordingly in doPost() method. E.g.:

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
        User user = userService.find(username, password);
    
        if (user != null) {
            request.getSession().setAttribute("user", user); // Login user.
            response.sendRedirect("home"); // Redirect to home page.
        } else {
            request.setAttribute("message", "Unknown username/password. Please retry."); // Store error message in request scope.
            request.getRequestDispatcher("/WEB-INF/login.jsp").forward(request, response); // Forward to JSP page to redisplay login form with error.
        }
    }
    

    This way dealing with different result page destinations is easier: redisplaying the form with validation errors in case of an error (in this particular example you can redisplay it using ${message} in EL), or just taking to the desired target page in case of success.


  • If you want to invoke some Java code to control the execution plan and/or the destination of the request and the response, then implement a servlet according to the MVC's Front Controller Pattern. E.g.:

    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        try {
            Action action = ActionFactory.getAction(request);
            String view = action.execute(request, response);
    
            if (view.equals(request.getPathInfo().substring(1)) {
                request.getRequestDispatcher("/WEB-INF/" + view + ".jsp").forward(request, response);
            } else {
                response.sendRedirect(view);
            }
        } catch (Exception e) {
            throw new ServletException("Executing action failed.", e);
        }
    }
    

    Or just adopt an MVC framework like JSF, Spring MVC, Wicket, etc so that you end up with just a JSP/Facelets page and a JavaBean class without the need for a custom servlet.


  • If you want to invoke some Java code to control the flow inside a JSP page, then you need to grab an (existing) flow control taglib like JSTL core. E.g. displaying List<Product> in a table:

    <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
    ...
    <table>
        <c:forEach items="${products}" var="product">
            <tr>
                <td>${product.name}</td>
                <td>${product.description}</td>
                <td>${product.price}</td>
            </tr>
        </c:forEach>
    </table>
    

    With XML-style tags which fit nicely among all that HTML, the code is better readable (and thus better maintainable) than a bunch of scriptlets with various opening and closing braces ("Where the heck does this closing brace belong to?"). An easy aid is to configure your web application to throw an exception whenever scriptlets are still been used by adding the following piece to web.xml:

    <jsp-config>
        <jsp-property-group>
            <url-pattern>*.jsp</url-pattern>
            <scripting-invalid>true</scripting-invalid>
        </jsp-property-group>
    </jsp-config>
    

    In Facelets, the successor of JSP, which is part of the Java EE provided MVC framework JSF, it is already not possible to use scriptlets. This way you're automatically forced to do things "the right way".


  • If you want to invoke some Java code to access and display "backend" data inside a JSP page, then you need to use EL (Expression Language), those ${} things. E.g. redisplaying submitted input values:

    <input type="text" name="foo" value="${param.foo}" />
    

    The ${param.foo} displays the outcome of request.getParameter("foo").


  • If you want to invoke some utility Java code directly in the JSP page (typically public static methods), then you need to define them as EL functions. There's a standard functions taglib in JSTL, but you can also easily create functions yourself. Here's an example how JSTL fn:escapeXml is useful to prevent XSS attacks.

    <%@ taglib uri="http://java.sun.com/jsp/jstl/functions" prefix="fn" %>
    ...
    <input type="text" name="foo" value="${fn:escapeXml(param.foo)}" />
    

    Note that the XSS sensitivity is in no way specifically related to Java/JSP/JSTL/EL/whatever, this problem needs to be taken into account in every web application you develop. The problem of scriptlets is that it provides no way of builtin preventions, at least not using the standard Java API. JSP's successor Facelets has already implicit HTML escaping, so you don't need to worry about XSS holes in Facelets.

See also:

REST API 404: Bad URI, or Missing Resource?

404 is just the HTTP response code. On top of that, you can provide a response body and/or other headers with a more meaningful error message that developers will see.

How can I inspect the file system of a failed `docker build`?

Debugging build step failures is indeed very annoying.

The best solution I have found is to make sure that each step that does real work succeeds, and adding a check after those that fails. That way you get a committed layer that contains the outputs of the failed step that you can inspect.

A Dockerfile, with an example after the # Run DB2 silent installer line:

#
# DB2 10.5 Client Dockerfile (Part 1)
#
# Requires
#   - DB2 10.5 Client for 64bit Linux ibm_data_server_runtime_client_linuxx64_v10.5.tar.gz
#   - Response file for DB2 10.5 Client for 64bit Linux db2rtcl_nr.rsp 
#
#
# Using Ubuntu 14.04 base image as the starting point.
FROM ubuntu:14.04

MAINTAINER David Carew <[email protected]>

# DB2 prereqs (also installing sharutils package as we use the utility uuencode to generate password - all others are required for the DB2 Client) 
RUN dpkg --add-architecture i386 && apt-get update && apt-get install -y sharutils binutils libstdc++6:i386 libpam0g:i386 && ln -s /lib/i386-linux-gnu/libpam.so.0 /lib/libpam.so.0
RUN apt-get install -y libxml2


# Create user db2clnt
# Generate strong random password and allow sudo to root w/o password
#
RUN  \
   adduser --quiet --disabled-password -shell /bin/bash -home /home/db2clnt --gecos "DB2 Client" db2clnt && \
   echo db2clnt:`dd if=/dev/urandom bs=16 count=1 2>/dev/null | uuencode -| head -n 2 | grep -v begin | cut -b 2-10` | chgpasswd && \
   adduser db2clnt sudo && \
   echo '%sudo ALL=(ALL) NOPASSWD:ALL' >> /etc/sudoers

# Install DB2
RUN mkdir /install
# Copy DB2 tarball - ADD command will expand it automatically
ADD v10.5fp9_linuxx64_rtcl.tar.gz /install/
# Copy response file
COPY  db2rtcl_nr.rsp /install/
# Run  DB2 silent installer
RUN mkdir /logs
RUN (/install/rtcl/db2setup -t /logs/trace -l /logs/log -u /install/db2rtcl_nr.rsp && touch /install/done) || /bin/true
RUN test -f /install/done || (echo ERROR-------; echo install failed, see files in container /logs directory of the last container layer; echo run docker run '<last image id>' /bin/cat /logs/trace; echo ----------)
RUN test -f /install/done

# Clean up unwanted files
RUN rm -fr /install/rtcl

# Login as db2clnt user
CMD su - db2clnt

Select tableview row programmatically

Swift 3/4/5 Solution

Select Row

let indexPath = IndexPath(row: 0, section: 0)
tblView.selectRow(at: indexPath, animated: true, scrollPosition: .bottom)
myTableView.delegate?.tableView!(myTableView, didSelectRowAt: indexPath)

DeSelect Row

let deselectIndexPath = IndexPath(row: 7, section: 0)
tblView.deselectRow(at: deselectIndexPath, animated: true)
tblView.delegate?.tableView!(tblView, didDeselectRowAt: indexPath)

Lombok is not generating getter and setter

1) Run the command java -jar lombok-1.16.10.jar. This needs to be run from the directory of your lombok.jar file.

2) Add the location manually by selecting the eclipse.ini file(Installed eclipse directory). Through “Specify location

Note : Don't add the eclipse.exe because it will make the eclipse editor corrupt.

How to add the eclipse.ini file

Split comma-separated input box values into array in jquery, and loop through it

use js split() method to create an array

var keywords = $('#searchKeywords').val().split(",");

then loop through the array using jQuery.each() function. as the documentation says:

In the case of an array, the callback is passed an array index and a corresponding array value each time

$.each(keywords, function(i, keyword){
   console.log(keyword);
});

git with IntelliJ IDEA: Could not read from remote repository

I solved this issue by re-adding remote repository: VCS -> Git -> Remotes.

Run Excel Macro from Outside Excel Using VBScript From Command Line

I generally store my macros in xlam add-ins separately from my workbooks so I wanted to open a workbook and then run a macro stored separately.

Since this required a VBS Script, I wanted to make it "portable" so I could use it by passing arguments. Here is the final script, which takes 3 arguments.

  • Full Path to Workbook
  • Macro Name
  • [OPTIONAL] Path to separate workbook with Macro

I tested it like so:

"C:\Temp\runmacro.vbs" "C:\Temp\Book1.xlam" "Hello"

"C:\Temp\runmacro.vbs" "C:\Temp\Book1.xlsx" "Hello" "%AppData%\Microsoft\Excel\XLSTART\Book1.xlam"

runmacro.vbs:

Set args = Wscript.Arguments

ws = WScript.Arguments.Item(0)
macro = WScript.Arguments.Item(1)
If wscript.arguments.count > 2 Then
 macrowb= WScript.Arguments.Item(2)
End If

LaunchMacro

Sub LaunchMacro() 
  Dim xl
  Dim xlBook  

  Set xl = CreateObject("Excel.application")
  Set xlBook = xl.Workbooks.Open(ws, 0, True)
  If wscript.arguments.count > 2 Then
   Set macrowb= xl.Workbooks.Open(macrowb, 0, True)
  End If
  'xl.Application.Visible = True ' Show Excel Window
  xl.Application.run macro
  'xl.DisplayAlerts = False  ' suppress prompts and alert messages while a macro is running
  'xlBook.saved = True ' suppresses the Save Changes prompt when you close a workbook
  'xl.activewindow.close
  xl.Quit

End Sub 

How do JavaScript closures work?

How I'd explain it to a six-year-old:

You know how grown-ups can own a house, and they call it home? When a mom has a child, the child doesn't really own anything, right? But its parents own a house, so whenever someone asks the child "Where's your home?", he/she can answer "that house!", and point to the house of its parents. A "Closure" is the ability of the child to always (even if abroad) be able to say it has a home, even though it's really the parent's who own the house.

Easy way to test a URL for 404 in PHP?

If your running php5 you can use:

$url = 'http://www.example.com';
print_r(get_headers($url, 1));

Alternatively with php4 a user has contributed the following:

/**
This is a modified version of code from "stuart at sixletterwords dot com", at 14-Sep-2005 04:52. This version tries to emulate get_headers() function at PHP4. I think it works fairly well, and is simple. It is not the best emulation available, but it works.

Features:
- supports (and requires) full URLs.
- supports changing of default port in URL.
- stops downloading from socket as soon as end-of-headers is detected.

Limitations:
- only gets the root URL (see line with "GET / HTTP/1.1").
- don't support HTTPS (nor the default HTTPS port).
*/

if(!function_exists('get_headers'))
{
    function get_headers($url,$format=0)
    {
        $url=parse_url($url);
        $end = "\r\n\r\n";
        $fp = fsockopen($url['host'], (empty($url['port'])?80:$url['port']), $errno, $errstr, 30);
        if ($fp)
        {
            $out  = "GET / HTTP/1.1\r\n";
            $out .= "Host: ".$url['host']."\r\n";
            $out .= "Connection: Close\r\n\r\n";
            $var  = '';
            fwrite($fp, $out);
            while (!feof($fp))
            {
                $var.=fgets($fp, 1280);
                if(strpos($var,$end))
                    break;
            }
            fclose($fp);

            $var=preg_replace("/\r\n\r\n.*\$/",'',$var);
            $var=explode("\r\n",$var);
            if($format)
            {
                foreach($var as $i)
                {
                    if(preg_match('/^([a-zA-Z -]+): +(.*)$/',$i,$parts))
                        $v[$parts[1]]=$parts[2];
                }
                return $v;
            }
            else
                return $var;
        }
    }
}

Both would have a result similar to:

Array
(
    [0] => HTTP/1.1 200 OK
    [Date] => Sat, 29 May 2004 12:28:14 GMT
    [Server] => Apache/1.3.27 (Unix)  (Red-Hat/Linux)
    [Last-Modified] => Wed, 08 Jan 2003 23:11:55 GMT
    [ETag] => "3f80f-1b6-3e1cb03b"
    [Accept-Ranges] => bytes
    [Content-Length] => 438
    [Connection] => close
    [Content-Type] => text/html
)

Therefore you could just check to see that the header response was OK eg:

$headers = get_headers($url, 1);
if ($headers[0] == 'HTTP/1.1 200 OK') {
//valid 
}

if ($headers[0] == 'HTTP/1.1 301 Moved Permanently') {
//moved or redirect page
}

W3C Codes and Definitions

How to initialize a nested struct?

You also could allocate using new and initialize all fields by hand

package main

type Configuration struct {
    Val   string
    Proxy struct {
        Address string
        Port    string
    }
}

func main() {
    c := new(Configuration)
    c.Val = "test"
    c.Proxy.Address = "addr"
    c.Proxy.Port = "80"
}

See in playground: https://play.golang.org/p/sFH_-HawO_M

Does JavaScript pass by reference?

Primitives are passed by value, and Objects are passed by "copy of a reference".

Specifically, when you pass an object (or array) you are (invisibly) passing a reference to that object, and it is possible to modify the contents of that object, but if you attempt to overwrite the reference it will not affect the copy of the reference held by the caller - i.e. the reference itself is passed by value:

function replace(ref) {
    ref = {};           // this code does _not_ affect the object passed
}

function update(ref) {
    ref.key = 'newvalue';  // this code _does_ affect the _contents_ of the object
}

var a = { key: 'value' };
replace(a);  // a still has its original value - it's unmodfied
update(a);   // the _contents_ of 'a' are changed

Getting error "No such module" using Xcode, but the framework is there

  1. Check whether you are using latest version of xcode.(If not update to the latest version supported by your device).
  2. Install cocoapods with sudo gem install cocoapods
  3. Run pod setup

I can confirm that the above steps solved my error :-)

How to change the docker image installation directory?

Following advice from comments I utilize Docker systemd documentation to improve this answer. Below procedure doesn't require reboot and is much cleaner.

First create directory and file for custom configuration:

sudo mkdir -p /etc/systemd/system/docker.service.d
sudo $EDITOR /etc/systemd/system/docker.service.d/docker-storage.conf

For docker version before 17.06-ce paste:

[Service]
ExecStart=
ExecStart=/usr/bin/docker daemon -H fd:// --graph="/mnt"

For docker after 17.06-ce paste:

[Service]
ExecStart=
ExecStart=/usr/bin/dockerd -H fd:// --data-root="/mnt"

Alternative method through daemon.json

I recently tried above procedure with 17.09-ce on Fedora 25 and it seem to not work. Instead of that simple modification in /etc/docker/daemon.json do the trick:

{
    "graph": "/mnt",
    "storage-driver": "overlay"
}

Despite the method you have to reload configuration and restart Docker:

sudo systemctl daemon-reload
sudo systemctl restart docker

To confirm that Docker was reconfigured:

docker info|grep "loop file"

In recent version (17.03) different command is required:

docker info|grep "Docker Root Dir"

Output should look like this:

 Data loop file: /mnt/devicemapper/devicemapper/data
 Metadata loop file: /mnt/devicemapper/devicemapper/metadata

Or:

 Docker Root Dir: /mnt

Then you can safely remove old Docker storage:

rm -rf /var/lib/docker

How to create a DB for MongoDB container on start up?

If you are looking to remove usernames and passwords from your docker-compose.yml you can use Docker Secrets, here is how I have approached it.

version: '3.6'

services:
  db:
    image: mongo:3
    container_name: mycontainer
  secrets:
    - MONGO_INITDB_ROOT_USERNAME
    - MONGO_INITDB_ROOT_PASSWORD
  environment:
    - MONGO_INITDB_ROOT_USERNAME_FILE=/var/run/secrets/MONGO_INITDB_ROOT_USERNAME
    - MONGO_INITDB_ROOT_PASSWORD_FILE=/var/run/secrets/MONGO_INITDB_ROOT_PASSWORD
secrets:
  MONGO_INITDB_ROOT_USERNAME:
    file:  secrets/${NODE_ENV}_mongo_root_username.txt
  MONGO_INITDB_ROOT_PASSWORD:
    file:  secrets/${NODE_ENV}_mongo_root_password.txt

I have use the file: option for my secrets however, you can also use external: and use the secrets in a swarm.

The secrets are available to any script in the container at /var/run/secrets

The Docker documentation has this to say about storing sensitive data...

https://docs.docker.com/engine/swarm/secrets/

You can use secrets to manage any sensitive data which a container needs at runtime but you don’t want to store in the image or in source control, such as:

Usernames and passwords TLS certificates and keys SSH keys Other important data such as the name of a database or internal server Generic strings or binary content (up to 500 kb in size)

How to parseInt in Angular.js

You cannot (at least at the moment) use parseInt inside angular expressions, as they're not evaluated directly. Quoting the doc:

Angular does not use JavaScript's eval() to evaluate expressions. Instead Angular's $parse service processes these expressions.

Angular expressions do not have access to global variables like window, document or location. This restriction is intentional. It prevents accidental access to the global state – a common source of subtle bugs.

So you can define a total() method in your controller, then use it in the expression:

// ... somewhere in controller
$scope.total = function() { 
  return parseInt($scope.num1) + parseInt($scope.num2) 
}

// ... in HTML
Total: {{ total() }}

Still, that seems to be rather bulky for a such a simple operation as adding the numbers. The alternative is converting the results with -0 op:

Total: {{num1-0 + (num2-0)|number}}

... but that'll obviously won't parseInt values, only cast them to Numbers (|number filter prevents showing null if this cast results in NaN). So choose the approach that suits your particular case.

Does Java have a path joining method?

One way is to get system properties that give you the path separator for the operating system, this tutorial explains how. You can then use a standard string join using the file.separator.

Css height in percent not working

the root parent have to be in pixels if you want to work freely with percents,

<body style="margin: 0px; width: 1886px; height: 939px;">
<div id="containerA" class="containerA" style="height:65%;width:100%;">
    <div id="containerAinnerDiv" style="position: relative; background-color: aqua;width:70%;height: 80%;left:15%;top:10%;">
       <div style="height: 100%;width: 50%;float: left;"></div>
       <div style="height: 100%;width: 28%;float:left">
            <img src="img/justimage.png" style="max-width:100%;max-height:100%;">
       </div>
       <div style="height: 100%;width: 22%;float: left;"></div>
    </div>
</div>
</body>

Remove blank lines with grep

Do lines in the file have whitespace characters?

If so then

grep "\S" file.txt

Otherwise

grep . file.txt

Answer obtained from: https://serverfault.com/a/688789

Setting max-height for table cell contents

Just put the labels in a div inside the TD and put the height and overflow.. like below.

<table>
<tr>
  <td><div style="height:40px; overflow:hidden">Sample</div></td>
  <td><div style="height:40px; overflow:hidden">Text</div></td>
  <td><div style="height:40px; overflow:hidden">Here</div></td>
</tr>
</table>

html cellpadding the left side of a cell

I recently had to do this to create half decent looking emails for an email client that did not support the CSS necessary. For an HTML only solution I use a wrapping table to provide the padding.

_x000D_
_x000D_
<table border="1" cellspacing="0" cellpadding="0">_x000D_
    <tr><td height="5" colspan="3"></td></tr>_x000D_
    <tr>_x000D_
        <td width="5"></td>_x000D_
        <td>_x000D_
            This cells padding matches what you want._x000D_
            <ul>_x000D_
                <li>5px Left, Top, Bottom padding</li>_x000D_
                <li>10px on the right</li>_x000D_
            </ul>    _x000D_
            You can then put your table inside this_x000D_
            cell with no spacing or padding set.                    _x000D_
        </td>_x000D_
        <td width="10"></td>_x000D_
    </tr>_x000D_
    <tr><td height="5" colspan="3"></td></tr>_x000D_
</table>
_x000D_
_x000D_
_x000D_

As of 2017 you would only do this for old email client support, it's pretty overkill.

How to center buttons in Twitter Bootstrap 3?

For Bootstrap 3

we divide the space with the columns, we use 8 small columns (col-xs-8), we leave 4 empty columns (col-xs-offset-4) and we apply the property (center-block)

<!--Footer-->
<div class="modal-footer">
  <div class="col-xs-8 col-xs-offset-4 center-block">
    <button type="submit" class="btn btn-primary">Enviar</button>
    <button type="button" class="btn btn-danger" data-dismiss="modal">Cerrar</button>
    </div>
</div>

For Bootstrap 4

We use Spacing, Bootstrap includes a wide range of abbreviated and padded response margin utility classes to modify the appearance of an element. The classes are named using the format {property}{sides}-{size} for xs and {property}{sides}-{breakpoint}-{size} for sm, md, lg, and xl.

more info here: https://getbootstrap.com/docs/4.1/utilities/spacing/

<!--Footer-->
<div class="modal-footer">
  <button type="submit" class="btn btn-primary ml-auto">Enviar</button>
  <button type="button" class="btn btn-danger mr-auto" data-dismiss="modal">Cerrar</button>
</div>

Get width height of remote image from url

Get image size with jQuery
(depending on which formatting method is more suitable for your preferences):

function getMeta(url){
    $('<img/>',{
        src: url,
        on: {
            load: (e) => {
                console.log('image size:', $(e.target).width(), $(e.target).height());
            },
        }
    });
}

or

function getMeta(url){
    $('<img/>',{
        src: url,
    }).on({
        load: (e) => {
            console.log('image size:', $(e.target).width(), $(e.target).height());
        },
    });
}

Getting the parent of a directory in Bash

This would go up to the parent folder

cd ../

How to calculate a Mod b in Casio fx-991ES calculator

As far as I know, that calculator does not offer mod functions. You can however computer it by hand in a fairly straightforward manner. Ex.

(1)50 mod 3

(2)50/3 = 16.66666667

(3)16.66666667 - 16 = 0.66666667

(4)0.66666667 * 3 = 2

Therefore 50 mod 3 = 2

Things to Note: On line 3, we got the "minus 16" by looking at the result from line (2) and ignoring everything after the decimal. The 3 in line (4) is the same 3 from line (1).

Hope that Helped.

Edit As a result of some trials you may get x.99991 which you will then round up to the number x+1.

Java: Calculating the angle between two points in degrees

I started with johncarls solution, but needed to adjust it to get exactly what I needed. Mainly, I needed it to rotate clockwise when the angle increased. I also needed 0 degrees to point NORTH. His solution got me close, but I decided to post my solution as well in case it helps anyone else.

I've added some additional comments to help explain my understanding of the function in case you need to make simple modifications.

/**
 * Calculates the angle from centerPt to targetPt in degrees.
 * The return should range from [0,360), rotating CLOCKWISE, 
 * 0 and 360 degrees represents NORTH,
 * 90 degrees represents EAST, etc...
 *
 * Assumes all points are in the same coordinate space.  If they are not, 
 * you will need to call SwingUtilities.convertPointToScreen or equivalent 
 * on all arguments before passing them  to this function.
 *
 * @param centerPt   Point we are rotating around.
 * @param targetPt   Point we want to calcuate the angle to.  
 * @return angle in degrees.  This is the angle from centerPt to targetPt.
 */
public static double calcRotationAngleInDegrees(Point centerPt, Point targetPt)
{
    // calculate the angle theta from the deltaY and deltaX values
    // (atan2 returns radians values from [-PI,PI])
    // 0 currently points EAST.  
    // NOTE: By preserving Y and X param order to atan2,  we are expecting 
    // a CLOCKWISE angle direction.  
    double theta = Math.atan2(targetPt.y - centerPt.y, targetPt.x - centerPt.x);

    // rotate the theta angle clockwise by 90 degrees 
    // (this makes 0 point NORTH)
    // NOTE: adding to an angle rotates it clockwise.  
    // subtracting would rotate it counter-clockwise
    theta += Math.PI/2.0;

    // convert from radians to degrees
    // this will give you an angle from [0->270],[-180,0]
    double angle = Math.toDegrees(theta);

    // convert to positive range [0-360)
    // since we want to prevent negative angles, adjust them now.
    // we can assume that atan2 will not return a negative value
    // greater than one partial rotation
    if (angle < 0) {
        angle += 360;
    }

    return angle;
}

How to have a transparent ImageButton: Android

DON'T USE A TRANSAPENT OR NULL LAYOUT because then the button (or the generic view) will no more highlight at click!!!

I had the same problem and finally I found the correct attribute from Android API to solve the problem. It can apply to any view.

Use this in the button specifications:

android:background="?android:selectableItemBackground"

Func delegate with no return type

... takes no arguments and has a void return type?

I believe Action is a solution to this.

jQuery: go to URL with target="_blank"

The .ready function is used to insert the attribute once the page has finished loading.

$(document).ready(function() {
     $("class name or id a.your class name").attr({"target" : "_blank"})
})

Detecting which UIButton was pressed in a UITableView

With Swift 4.2 and iOS 12, you can choose one the 5 following complete examples in order to solve your problem.


#1. Using UIView's convert(_:to:) and UITableView's indexPathForRow(at:)

import UIKit

private class CustomCell: UITableViewCell {

    let button = UIButton(type: .system)

    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)

        button.setTitle("Tap", for: .normal)
        contentView.addSubview(button)

        button.translatesAutoresizingMaskIntoConstraints = false
        button.centerXAnchor.constraint(equalTo: contentView.centerXAnchor).isActive = true
        button.centerYAnchor.constraint(equalTo: contentView.centerYAnchor).isActive = true
        button.topAnchor.constraint(equalToSystemSpacingBelow: contentView.topAnchor, multiplier: 1).isActive = true
        button.leadingAnchor.constraint(greaterThanOrEqualToSystemSpacingAfter: contentView.leadingAnchor, multiplier: 1).isActive = true
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

}
import UIKit

class TableViewController: UITableViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.register(CustomCell.self, forCellReuseIdentifier: "CustomCell")
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 3
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "CustomCell", for: indexPath) as! CustomCell
        cell.button.addTarget(self, action: #selector(customCellButtonTapped), for: .touchUpInside)
        return cell
    }

    @objc func customCellButtonTapped(_ sender: UIButton) {
        let point = sender.convert(CGPoint.zero, to: tableView)
        guard let indexPath = tableView.indexPathForRow(at: point) else { return }
        print(indexPath)
    }

}

#2. Using UIView's convert(_:to:) and UITableView's indexPathForRow(at:) (alternative)

This is an alternative to the previous example where we pass nil to the target parameter in addTarget(_:action:for:). This way, if the first responder does not implement the action, it will be send to the next responder in the responder chain until until a proper implementation is found.

import UIKit

private class CustomCell: UITableViewCell {

    let button = UIButton(type: .system)

    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)

        button.setTitle("Tap", for: .normal)
        button.addTarget(nil, action: #selector(TableViewController.customCellButtonTapped), for: .touchUpInside)
        contentView.addSubview(button)

        button.translatesAutoresizingMaskIntoConstraints = false
        button.centerXAnchor.constraint(equalTo: contentView.centerXAnchor).isActive = true
        button.centerYAnchor.constraint(equalTo: contentView.centerYAnchor).isActive = true
        button.topAnchor.constraint(equalToSystemSpacingBelow: contentView.topAnchor, multiplier: 1).isActive = true
        button.leadingAnchor.constraint(greaterThanOrEqualToSystemSpacingAfter: contentView.leadingAnchor, multiplier: 1).isActive = true
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

}
import UIKit

class TableViewController: UITableViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.register(CustomCell.self, forCellReuseIdentifier: "CustomCell")
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 3
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "CustomCell", for: indexPath) as! CustomCell
        return cell
    }

    @objc func customCellButtonTapped(_ sender: UIButton) {
        let point = sender.convert(CGPoint.zero, to: tableView)
        guard let indexPath = tableView.indexPathForRow(at: point) else { return }
        print(indexPath)
    }

}

#3. Using UITableView's indexPath(for:) and delegate pattern

In this example, we set the view controller as the delegate of the cell. When the cell's button is tapped, it triggers a call to the appropriate method of the delegate.

import UIKit

protocol CustomCellDelegate: AnyObject {
    func customCellButtonTapped(_ customCell: CustomCell)
}

class CustomCell: UITableViewCell {

    let button = UIButton(type: .system)
    weak var delegate: CustomCellDelegate?

    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)

        button.setTitle("Tap", for: .normal)
        button.addTarget(self, action: #selector(buttonTapped), for: .touchUpInside)
        contentView.addSubview(button)

        button.translatesAutoresizingMaskIntoConstraints = false
        button.centerXAnchor.constraint(equalTo: contentView.centerXAnchor).isActive = true
        button.centerYAnchor.constraint(equalTo: contentView.centerYAnchor).isActive = true
        button.topAnchor.constraint(equalToSystemSpacingBelow: contentView.topAnchor, multiplier: 1).isActive = true
        button.leadingAnchor.constraint(greaterThanOrEqualToSystemSpacingAfter: contentView.leadingAnchor, multiplier: 1).isActive = true
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    @objc func buttonTapped(sender: UIButton) {
        delegate?.customCellButtonTapped(self)
    }

}
import UIKit

class TableViewController: UITableViewController, CustomCellDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.register(CustomCell.self, forCellReuseIdentifier: "CustomCell")
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 3
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "CustomCell", for: indexPath) as! CustomCell
        cell.delegate = self
        return cell
    }

    // MARK: - CustomCellDelegate

    func customCellButtonTapped(_ customCell: CustomCell) {
        guard let indexPath = tableView.indexPath(for: customCell) else { return }
        print(indexPath)
    }

}

#4. Using UITableView's indexPath(for:) and a closure for delegation

This is an alternative to the previous example where we use a closure instead of a protocol-delegate declaration to handle the button tap.

import UIKit

class CustomCell: UITableViewCell {

    let button = UIButton(type: .system)
    var buttontappedClosure: ((CustomCell) -> Void)?

    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)

        button.setTitle("Tap", for: .normal)
        button.addTarget(self, action: #selector(buttonTapped), for: .touchUpInside)
        contentView.addSubview(button)

        button.translatesAutoresizingMaskIntoConstraints = false
        button.centerXAnchor.constraint(equalTo: contentView.centerXAnchor).isActive = true
        button.centerYAnchor.constraint(equalTo: contentView.centerYAnchor).isActive = true
        button.topAnchor.constraint(equalToSystemSpacingBelow: contentView.topAnchor, multiplier: 1).isActive = true
        button.leadingAnchor.constraint(greaterThanOrEqualToSystemSpacingAfter: contentView.leadingAnchor, multiplier: 1).isActive = true
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    @objc func buttonTapped(sender: UIButton) {
        buttontappedClosure?(self)
    }

}
import UIKit

class TableViewController: UITableViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.register(CustomCell.self, forCellReuseIdentifier: "CustomCell")
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 3
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "CustomCell", for: indexPath) as! CustomCell
        cell.buttontappedClosure = { [weak tableView] cell in
            guard let indexPath = tableView?.indexPath(for: cell) else { return }
            print(indexPath)
        }
        return cell
    }

}

#5. Using UITableViewCell's accessoryType and UITableViewDelegate's tableView(_:accessoryButtonTappedForRowWith:)

If your button is a UITableViewCell's standard accessory control, any tap on it will trigger a call to UITableViewDelegate's tableView(_:accessoryButtonTappedForRowWith:), allowing you to get the related index path.

import UIKit

private class CustomCell: UITableViewCell {

    override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        accessoryType = .detailButton
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

}
import UIKit

class TableViewController: UITableViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        tableView.register(CustomCell.self, forCellReuseIdentifier: "CustomCell")
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 3
    }

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "CustomCell", for: indexPath) as! CustomCell
        return cell
    }

    override func tableView(_ tableView: UITableView, accessoryButtonTappedForRowWith indexPath: IndexPath) {
        print(indexPath)
    }

}

Best way to check if object exists in Entity Framework?

I had some trouble with this - my EntityKey consists of three properties (PK with 3 columns) and I didn't want to check each of the columns because that would be ugly. I thought about a solution that works all time with all entities.

Another reason for this is I don't like to catch UpdateExceptions every time.

A little bit of Reflection is needed to get the values of the key properties.

The code is implemented as an extension to simplify the usage as:

context.EntityExists<MyEntityType>(item);

Have a look:

public static bool EntityExists<T>(this ObjectContext context, T entity)
        where T : EntityObject
    {
        object value;
        var entityKeyValues = new List<KeyValuePair<string, object>>();
        var objectSet = context.CreateObjectSet<T>().EntitySet;
        foreach (var member in objectSet.ElementType.KeyMembers)
        {
            var info = entity.GetType().GetProperty(member.Name);
            var tempValue = info.GetValue(entity, null);
            var pair = new KeyValuePair<string, object>(member.Name, tempValue);
            entityKeyValues.Add(pair);
        }
        var key = new EntityKey(objectSet.EntityContainer.Name + "." + objectSet.Name, entityKeyValues);
        if (context.TryGetObjectByKey(key, out value))
        {
            return value != null;
        }
        return false;
    }

List all column except for one in R

You can index and use a negative sign to drop the 3rd column:

data[,-3]

Or you can list only the first 2 columns:

data[,c("c1", "c2")]
data[,1:2]

Don't forget the comma and referencing data frames works like this: data[row,column]

Stop executing further code in Java

You can just use return to end the method's execution

What is memoization and how can I use it in Python?

Memoization effectively refers to remembering ("memoization" ? "memorandum" ? to be remembered) results of method calls based on the method inputs and then returning the remembered result rather than computing the result again. You can think of it as a cache for method results. For further details, see page 387 for the definition in Introduction To Algorithms (3e), Cormen et al.

A simple example for computing factorials using memoization in Python would be something like this:

factorial_memo = {}
def factorial(k):
    if k < 2: return 1
    if k not in factorial_memo:
        factorial_memo[k] = k * factorial(k-1)
    return factorial_memo[k]

You can get more complicated and encapsulate the memoization process into a class:

class Memoize:
    def __init__(self, f):
        self.f = f
        self.memo = {}
    def __call__(self, *args):
        if not args in self.memo:
            self.memo[args] = self.f(*args)
        #Warning: You may wish to do a deepcopy here if returning objects
        return self.memo[args]

Then:

def factorial(k):
    if k < 2: return 1
    return k * factorial(k - 1)

factorial = Memoize(factorial)

A feature known as "decorators" was added in Python 2.4 which allow you to now simply write the following to accomplish the same thing:

@Memoize
def factorial(k):
    if k < 2: return 1
    return k * factorial(k - 1)

The Python Decorator Library has a similar decorator called memoized that is slightly more robust than the Memoize class shown here.

Spring MVC: difference between <context:component-scan> and <annotation-driven /> tags?

<context:component-scan base-package="" /> 

tells Spring to scan those packages for Annotations.

<mvc:annotation-driven> 

registers a RequestMappingHanderMapping, a RequestMappingHandlerAdapter, and an ExceptionHandlerExceptionResolver to support the annotated controller methods like @RequestMapping, @ExceptionHandler, etc. that come with MVC.

This also enables a ConversionService that supports Annotation driven formatting of outputs as well as Annotation driven validation for inputs. It also enables support for @ResponseBody which you can use to return JSON data.

You can accomplish the same things using Java-based Configuration using @ComponentScan(basePackages={"...", "..."} and @EnableWebMvc in a @Configuration class.

Check out the 3.1 documentation to learn more.

http://static.springsource.org/spring/docs/3.1.x/spring-framework-reference/html/mvc.html#mvc-config

How to echo JSON in PHP

if you want to encode or decode an array from or to JSON you can use these functions

$myJSONString = json_encode($myArray);
$myArray = json_decode($myString);

json_encode will result in a JSON string, built from an (multi-dimensional) array. json_decode will result in an Array, built from a well formed JSON string

with json_decode you can take the results from the API and only output what you want, for example:

echo $myArray['payload']['ign'];

Detect whether there is an Internet connection available on Android

Step 1: Create a class AppStatus in your project(you can give any other name also). Then please paste the given below lines into your code:

import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.util.Log;


public class AppStatus {

    private static AppStatus instance = new AppStatus();
    static Context context;
    ConnectivityManager connectivityManager;
    NetworkInfo wifiInfo, mobileInfo;
    boolean connected = false;

    public static AppStatus getInstance(Context ctx) {
        context = ctx.getApplicationContext();
        return instance;
    }

    public boolean isOnline() {
        try {
            connectivityManager = (ConnectivityManager) context
                        .getSystemService(Context.CONNECTIVITY_SERVICE);

        NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
        connected = networkInfo != null && networkInfo.isAvailable() &&
                networkInfo.isConnected();
        return connected;


        } catch (Exception e) {
            System.out.println("CheckConnectivity Exception: " + e.getMessage());
            Log.v("connectivity", e.toString());
        }
        return connected;
    }
}

Step 2: Now to check if the your device has network connectivity then just add this code snippet where ever you want to check ...

if (AppStatus.getInstance(this).isOnline()) {

    Toast.makeText(this,"You are online!!!!",8000).show();

} else {

    Toast.makeText(this,"You are not online!!!!",8000).show();
    Log.v("Home", "############################You are not online!!!!");    
}

Error starting Tomcat from NetBeans - '127.0.0.1*' is not recognized as an internal or external command

Assuming you are on Windows (this bug is caused by the crappy bat files escaping), It is a bug introduced in the latest versions (7.0.56 and 8.0.14) to workaround another bug. Try to remove the " around the JAVA_OPTS declaration in catalina.bat. It fixed it for me with Tomcat 7.0.56 yesterday.

In 7.0.56 in bin/catalina.bat:179 and 184

:noJuliConfig
set "JAVA_OPTS=%JAVA_OPTS% %LOGGING_CONFIG%"

..

:noJuliManager
set "JAVA_OPTS=%JAVA_OPTS% %LOGGING_MANAGER%"

to

:noJuliConfig
set JAVA_OPTS=%JAVA_OPTS% %LOGGING_CONFIG%

.. 

:noJuliManager
set JAVA_OPTS=%JAVA_OPTS% %LOGGING_MANAGER%

For your asterisk, it might only be a configuration of yours somewhere that appends it to the host declaration.

I saw this on Tomcat's bugtracker yesterday but I can't find the link again. Edit Found it! https://issues.apache.org/bugzilla/show_bug.cgi?id=56895

I hope it fixes your problem.

How do you find the current user in a Windows environment?

It's always annoyed me how Windows doesn't have some of more useful little scripting utilities of Unix, such as who/whoami, sed and AWK. Anyway, if you want something foolproof, get Visual Studio Express and compile the following:

#include <windows.h>
#include <stdio.h>

int main(int argc, char **argv) {
    printf("%s", GetUserName());
}

And just use that in your batch file.

How to trigger the window resize event in JavaScript?

Response with RxJS

Say Like something in Angular

size$: Observable<number> = fromEvent(window, 'resize').pipe(
            debounceTime(250),
            throttleTime(300),
            mergeMap(() => of(document.body.clientHeight)),
            distinctUntilChanged(),
            startWith(document.body.clientHeight),
          );

If manual subscription desired (Or Not Angular)

this.size$.subscribe((g) => {
      console.log('clientHeight', g);
    })

Since my intial startWith Value might be incorrect (dispatch for correction)

window.dispatchEvent(new Event('resize'));

In say Angular (I could..)

<div class="iframe-container"  [style.height.px]="size$ | async" >..

How do you overcome the svn 'out of date' error?

In my case only deleting of the local version and re checkout of fresh copy was a solution.

How do I send a POST request as a JSON?

If your server is expecting the POST request to be json, then you would need to add a header, and also serialize the data for your request...

Python 2.x

import json
import urllib2

data = {
        'ids': [12, 3, 4, 5, 6]
}

req = urllib2.Request('http://example.com/api/posts/create')
req.add_header('Content-Type', 'application/json')

response = urllib2.urlopen(req, json.dumps(data))

Python 3.x

https://stackoverflow.com/a/26876308/496445


If you don't specify the header, it will be the default application/x-www-form-urlencoded type.

ETag vs Header Expires

One additional thing I would like to mention that some of the answers may have missed is the downside to having both ETags and Expires/Cache-control in your headers.

Depending on your needs it may just add extra bytes in your headers which may increase packets which means more TCP overhead. Again, you should see if the overhead of having both things in your headers is necessary or will it just add extra weight in your requests which reduces performance.

You can read more about it on this excellent blog post by Kyle Simpson: http://calendar.perfplanet.com/2010/bloated-request-response-headers/

Make body have 100% of the browser height

html {
    background: url(images/bg.jpg) no-repeat center center fixed; 
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
    min-height: 100%;
}
html body {
    min-height: 100%
}

Works for all major browsers: FF, Chrome, Opera, IE9+. Works with Background images and gradients. Scrollbars are available as content needs.

Passing functions with arguments to another function in Python?

Here is a way to do it with a closure:

    def generate_add_mult_func(func):
        def function_generator(x):
            return reduce(func,range(1,x))
        return function_generator

    def add(x,y):
        return x+y

    def mult(x,y):
        return x*y

    adding=generate_add_mult_func(add)
    multiplying=generate_add_mult_func(mult)

    print adding(10)
    print multiplying(10)

Unique Key constraints for multiple columns in Entity Framework

You need to define a composite key.

With data annotations it looks like this:

public class Entity
 {
   public string EntityId { get; set;}
   [Key]
   [Column(Order=0)]
   public int FirstColumn  { get; set;}
   [Key]
   [Column(Order=1)]
   public int SecondColumn  { get; set;}
 }

You can also do this with modelBuilder when overriding OnModelCreating by specifying:

modelBuilder.Entity<Entity>().HasKey(x => new { x.FirstColumn, x.SecondColumn });

How to generate random number with the specific length in python

You could create a function who consumes an list of int, transforms in string to concatenate and cast do int again, something like this:

import random

def generate_random_number(length):
    return int(''.join([str(random.randint(0,10)) for _ in range(length)]))

SQLite - getting number of rows in a database

In SQL, NULL = NULL is false, you usually have to use IS NULL:

SELECT CASE WHEN MAX(id) IS NULL THEN 0 ELSE (MAX(id) + 1) END FROM words

But, if you want the number of rows, you should just use count(id) since your solution will give 10 if your rows are (0,1,3,5,9) where it should give 5.

If you can guarantee you will always ids from 0 to N, max(id)+1 may be faster depending on the index implementation (it may be faster to traverse the right side of a balanced tree rather than traversing the whole tree, counting.

But that's very implementation-specific and I would advise against relying on it, not least because it locks your performance to a specific DBMS.

Java - Convert integer to string

Always use either String.valueOf(number) or Integer.toString(number).

Using "" + number is an overhead and does the following:

StringBuilder sb = new StringBuilder();
sb.append("");
sb.append(number);
return sb.toString();

How to display custom view in ActionBar?

I struggled with this myself, and tried Tomik's answer. However, this didn't made the layout to full available width on start, only when you add something to the view.

You'll need to set the LayoutParams.FILL_PARENT when adding the view:

//I'm using actionbarsherlock, but it's the same.
LayoutParams layout = new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);
getSupportActionBar().setCustomView(overlay, layout); 

This way it completely fills the available space. (You may need to use Tomik's solution too).

Show empty string when date field is 1/1/1900

Use this inside of query, no need to create extra variables.

CASE WHEN CreatedDate = '19000101' THEN '' WHEN CreatedDate =
'18000101' THEN ''  ELSE CONVERT(CHAR(10), CreatedDate, 120) + ' ' +
CONVERT(CHAR(8), CreatedDate, 108) END as 'Created Date'

Works like a charm.

Java : Cannot format given Object as a Date

DateFormat.format only works on Date values.

You should use two SimpleDateFormat objects: one for parsing, and one for formatting. For example:

// Note, MM is months, not mm
DateFormat outputFormat = new SimpleDateFormat("MM/yyyy", Locale.US);
DateFormat inputFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSX", Locale.US);

String inputText = "2012-11-17T00:00:00.000-05:00";
Date date = inputFormat.parse(inputText);
String outputText = outputFormat.format(date);

EDIT: Note that you may well want to specify the time zone and/or locale in your formats, and you should also consider using Joda Time instead of all of this to start with - it's a much better date/time API.

Rethrowing exceptions in Java without losing the stack trace

You can also wrap the exception in another one AND keep the original stack trace by passing in the Exception as a Throwable as the cause parameter:

try
{
   ...
}
catch (Exception e)
{
     throw new YourOwnException(e);
}

Alternative Windows shells, besides CMD.EXE?

I am a fan of Cmder, a package including clink, conemu, msysgit, and some cosmetic enhancements.

http://cmder.net/

https://github.com/cmderdev/cmder

https://chocolatey.org/packages/Cmder

enter image description here

Configuring so that pip install can work from github

You need the whole python package, with a setup.py file in it.

A package named foo would be:

foo # the installable package
+-- foo
¦   +-- __init__.py
¦   +-- bar.py
+-- setup.py

And install from github like:

$ pip install git+ssh://[email protected]/myuser/foo.git
or
$ pip install git+https://github.com/myuser/foo.git@v123
or
$ pip install git+https://github.com/myuser/foo.git@newbranch

More info at https://pip.pypa.io/en/stable/reference/pip_install/#vcs-support

Split string in C every white space

char arr[50];
gets(arr);
int c=0,i,l;
l=strlen(arr);

    for(i=0;i<l;i++){
        if(arr[i]==32){
            printf("\n");
        }
        else
        printf("%c",arr[i]);
    }

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()

XMLHttpRequest status 0 (responseText is empty)

I just had this issue because I used 0.0.0.0 as my server, changed it to localhost and it works.

Getting DOM element value using pure JavaScript

Pass the object:

doSomething(this)

You can get all data from object:

function(obj){
    var value = obj.value;
    var id = obj.id;
}

Or pass the id only:

doSomething(this.id)

Get the object and after that value:

function(id){
    var value = document.getElementById(id).value;  
}

Don't reload application when orientation changes

I dont know if the a best solution, but i describe it here:

First of all, you need certificate with you class Application of your app is in your manifest of this:

<application
    android:name=".App"
    ...

Second, in my class App i did like this:

public class App extends Application {
    public static boolean isOrientationChanged = false;

    @Override
    public void onCreate() {
        super.onCreate();
    }

    @Override
    public void onConfigurationChanged(@NotNull Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE ||
                newConfig.orientation == Configuration.ORIENTATION_PORTRAIT) {
            isOrientationChanged = true;
        }
    }

}

Third, you need to set a flag to Orientation Change, in my case, I always set it when the previous activity within the app navigation is called, so only calling once when the later activity is created.

isOrientationChanged = false;

So every time I change the orientation of my screen in that context, I set it every time it changes this setting, it checks if there is a change in orientation, if so, it validates it based on the value of that flag.

Basically, I had to use it whenever I made an asynchronous retrofit request, which he called every moment that changed orientation, constantly crashing the application:

if (!isOrientationChanged) {
    presenter.retrieveAddress(this, idClient, TYPE_ADDRESS);
}

I don't know if it's the most elegant and beautiful solution, but at least here it's functional :)

CSS: fixed position on x-axis but not y?

I just added position:absolute and that solved my problem.

Safely remove migration In Laravel

If the migration has been run (read: migrated) then you should roll back your migration to clear the history from your database table. Once you're rolled back you should be able to safely delete your migration file and then proceed with migrating again.

Unable to get spring boot to automatically create database schema

There are several possible causes:

  1. Your entity classes are in the same or in a sub-package relative one where you have you class with @EnableAutoConfiguration. If not then your spring app does not see them and hence will not create anything in db
  2. Check your config, it seems that you are using some hibernate specific options, try to replace them with:

    spring.jpa.database-platform=org.hibernate.dialect.MySQL5InnoDBDialect
    spring.jpa.hibernate.ddl-auto=update
    spring.datasource.driverClassName=com.mysql.jdbc.Driver
    spring.datasource.url=jdbc:mysql://localhost:3306/test
    spring.datasource.username=test
    spring.datasource.password=
    
  3. Your application.properties must be in src/main/resources folder.

If you did not specify dialect correctly it might try to default to bundled together with boot in-memory database and (as it was with me) I could see that it tries to connect to local HSQL (see console output) instance and fail at updating the schema.

Working with INTERVAL and CURDATE in MySQL

You need DATE_ADD/DATE_SUB:

AND v.date > (DATE_SUB(CURDATE(), INTERVAL 2 MONTH))
AND v.date < (DATE_SUB(CURDATE(), INTERVAL 1 MONTH))

should work.

How different is Scrum practice from Agile Practice?

Agile and SCRUM are related but distinct. Agile describes a set of guiding principles for building software through iterative development. Agile principles are best described in the Agile Manifesto. SCRUM is a specific set of rules to follow when practicing agile software development.

Create two-dimensional arrays and access sub-arrays in Ruby

I'm quite sure this can be very simple

2.0.0p247 :032 > list = Array.new(5)

 => [nil, nil, nil, nil, nil] 

2.0.0p247 :033 > list.map!{ |x| x = [0] }

 => [[0], [0], [0], [0], [0]] 

2.0.0p247 :034 > list[0][0]

  => 0

How to make function decorators and chain them together?

Decorate functions with different number of arguments:

def frame_tests(fn):
    def wrapper(*args):
        print "\nStart: %s" %(fn.__name__)
        fn(*args)
        print "End: %s\n" %(fn.__name__)
    return wrapper

@frame_tests
def test_fn1():
    print "This is only a test!"

@frame_tests
def test_fn2(s1):
    print "This is only a test! %s" %(s1)

@frame_tests
def test_fn3(s1, s2):
    print "This is only a test! %s %s" %(s1, s2)

if __name__ == "__main__":
    test_fn1()
    test_fn2('OK!')
    test_fn3('OK!', 'Just a test!')

Result:

Start: test_fn1  
This is only a test!  
End: test_fn1  
  
  
Start: test_fn2  
This is only a test! OK!  
End: test_fn2  
  
  
Start: test_fn3  
This is only a test! OK! Just a test!  
End: test_fn3  

How to place a div below another div?

what about changing the position: relative on your #content #text div to position: absolute

#content #text {
   position:absolute;
   width:950px;
   height:215px;
   color:red;
}

http://jsfiddle.net/CaZY7/12/

then you can use the css properties left and top to position within the #content div

TypeError: got multiple values for argument

This happens when a keyword argument is specified that overwrites a positional argument. For example, let's imagine a function that draws a colored box. The function selects the color to be used and delegates the drawing of the box to another function, relaying all extra arguments.

def color_box(color, *args, **kwargs):
    painter.select_color(color)
    painter.draw_box(*args, **kwargs)

Then the call

color_box("blellow", color="green", height=20, width=30)

will fail because two values are assigned to color: "blellow" as positional and "green" as keyword. (painter.draw_box is supposed to accept the height and width arguments).

This is easy to see in the example, but of course if one mixes up the arguments at call, it may not be easy to debug:

# misplaced height and width
color_box(20, 30, color="green")

Here, color is assigned 20, then args=[30] and color is again assigned "green".

How to get the parents of a Python class?

If you want to ensure they all get called, use super at all levels.

Java - Access is denied java.io.FileNotFoundException

Not exactly the case of this question but can be helpful. I got this exception when i call mkdirs() on new file instead of its parent

File file = new java.io.File(path);
//file.mkdirs(); // wrong! 
file.getParentFile().mkdirs(); // correct!
if (!file.exists()) {
    file.createNewFile();
} 

How do I get current scope dom-element in AngularJS controller?

The better and correct solution is to have a directive. The scope is the same, whether in the controller of the directive or the main controller. Use $element to do DOM operations. The method defined in the directive controller is accessible in the main controller.

Example, finding a child element:

var app = angular.module('myapp', []);
app.directive("testDir", function () {
    function link(scope, element) { 

    }
    return {
        restrict: "AE", 
        link: link, 
        controller:function($scope,$element){
            $scope.name2 = 'this is second name';
            var barGridSection = $element.find('#barGridSection'); //helps to find the child element.
    }
    };
})

app.controller('mainController', function ($scope) {
$scope.name='this is first name'
});

Renaming the current file in Vim

  • Write the file while editing - :w newname - to create a copy.
  • Start editing the new copy - :e#.
  • (Optionally) remove the old copy - :!rm oldname.

On Windows, the optional 3rd step changes a little:

  • (Optionally) remove old Windows copy - :!del oldname.

How can I call the 'base implementation' of an overridden virtual method?

I konow it's history question now. But for other googlers: you could write something like this. But this requires change in base class what makes it useless with external libraries.

class A
{
  void protoX() { Console.WriteLine("x"); }
  virtual void X() { protoX(); }
}

class B : A
{
  override void X() { Console.WriteLine("y"); }
}

class Program
{
  static void Main()
  {
    A b = new B();
    // Call A.X somehow, not B.X...
    b.protoX();


  }

How to get a tab character?

Sure there's an entity for tabs:

&#9;

(The tab is ASCII character 9, or Unicode U+0009.)

However, just like literal tabs (ones you type in to your text editor), all tab characters are treated as whitespace by HTML parsers and collapsed into a single space except those within a <pre> block, where literal tabs will be rendered as 8 spaces in a monospace font.

Java - checking if parseInt throws exception

You can use the try..catch statement in java, to capture an exception that may arise from Integer.parseInt().

Example:

try {
  int i = Integer.parseint(stringToParse);
  //parseInt succeded
} catch(Exception e)
{
   //parseInt failed
}

How to check if JavaScript object is JSON

The answer by @PeterWilkinson didn't work for me because a constructor for a "typed" object is customized to the name of that object. I had to work with typeof

function isJson(obj) {
    var t = typeof obj;
    return ['boolean', 'number', 'string', 'symbol', 'function'].indexOf(t) == -1;
}

How can I add a volume to an existing Docker container?

The best way is to copy all the files and folders inside a directory on your local file system by: docker cp [OPTIONS] CONTAINER:SRC_PATH DEST_PATH

SRC_PATH is on container DEST_PATH is on localhost

Then do docker-compose down attach a volume to the same DEST_PATH and run Docker containers by using docker-compose up -d

Add volume by following in docker-compose.yml

volumes:
 - DEST_PATH:SRC_PATH

Difference between chr(13) and chr(10)

Chr(10) is the Line Feed character and Chr(13) is the Carriage Return character.

You probably won't notice a difference if you use only one or the other, but you might find yourself in a situation where the output doesn't show properly with only one or the other. So it's safer to include both.


Historically, Line Feed would move down a line but not return to column 1:

This  
    is  
        a  
            test.

Similarly Carriage Return would return to column 1 but not move down a line:

This  
is  
a  
test.

Paste this into a text editor and then choose to "show all characters", and you'll see both characters present at the end of each line. Better safe than sorry.

Calculating width from percent to pixel then minus by pixel in LESS CSS

I think width: -moz-calc(25% - 1em); is what you are looking for. And you may want to give this Link a look for any further assistance

How to rotate the background image in the container?

Update 2020, May:

Setting position: absolute and then transform: rotate(45deg) will provide a background:

_x000D_
_x000D_
div {_x000D_
  height: 200px;_x000D_
  width: 200px;_x000D_
  outline: 2px dashed slateBlue;_x000D_
  overflow: hidden;_x000D_
}_x000D_
div img {_x000D_
  position: absolute;_x000D_
  transform: rotate(45deg);_x000D_
  z-index: -1;_x000D_
  top: 40px;_x000D_
  left: 40px;_x000D_
}
_x000D_
<div>_x000D_
  <img src="https://placekitten.com/120/120" />_x000D_
  <h1>Hello World!</h1>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Original Answer:

In my case, the image size is not so large that I cannot have a rotated copy of it. So, the image has been rotated with photoshop. An alternative to photoshop for rotating images is online tool too for rotating images. Once rotated, I'm working with the rotated-image in the background property.

div.with-background {
    background-image: url(/img/rotated-image.png);
    background-size:     contain;
    background-repeat:   no-repeat;
    background-position: top center;
}

Good Luck...

fatal: could not read Username for 'https://github.com': No such file or directory

trying the CreativeMagic solution, the credential problem is confirmed:

prompt>>>Username for 'https://github.com'

So, I changed my origin url with

git remote set-url --add origin http://github.com/user/repo

and

git push --set-upstream origin master

.attr('checked','checked') does not work

I don't think you can call

$.attr('checked',true);

because there is no element selector in the first place. $ must be followed by $('selector_name'). GOod luck!

How to get just the parent directory name of a specific file

For Kotlin :

 fun getFolderName() {
            
            val uri: Uri
            val cursor: Cursor?
    
            uri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI
            val projection = arrayOf(MediaStore.Audio.AudioColumns.DATA)
            cursor = requireActivity().contentResolver.query(uri, projection, null, null, null)
            if (cursor != null) {
                column_index_data = cursor.getColumnIndexOrThrow(MediaStore.Audio.AudioColumns.DATA)
            }
            
            while (cursor!!.moveToNext()) {
    
                absolutePathOfImage = cursor.getString(column_index_data)
    
    
                val fileName: String = File(absolutePathOfImage).parentFile.name
    }
}

How to add a 'or' condition in #ifdef

I am really OCD about maintaining strict column limits, and not a fan of "\" line continuation because you can't put a comment after it, so here is my method.

//|¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯|//
#ifdef  CONDITION_01             //|       |//
#define             TEMP_MACRO   //|       |//
#endif                           //|       |//
#ifdef  CONDITION_02             //|       |//
#define             TEMP_MACRO   //|       |//
#endif                           //|       |//
#ifdef  CONDITION_03             //|       |//
#define             TEMP_MACRO   //|       |//
#endif                           //|       |//
#ifdef              TEMP_MACRO   //|       |//
//|-  --  --  --  --  --  --  --  --  --  -|//

printf("[IF_CONDITION:(1|2|3)]\n");

//|-  --  --  --  --  --  --  --  --  --  -|//
#endif                           //|       |//
#undef              TEMP_MACRO   //|       |//
//|________________________________________|//

INSERT INTO ... SELECT FROM ... ON DUPLICATE KEY UPDATE

Although I am very late to this but after seeing some legitimate questions for those who wanted to use INSERT-SELECT query with GROUP BY clause, I came up with the work around for this.

Taking further the answer of Marcus Adams and accounting GROUP BY in it, this is how I would solve the problem by using Subqueries in the FROM Clause

INSERT INTO lee(exp_id, created_by, location, animal, starttime, endtime, entct, 
                inact, inadur, inadist, 
                smlct, smldur, smldist, 
                larct, lardur, lardist, 
                emptyct, emptydur)
SELECT sb.id, uid, sb.location, sb.animal, sb.starttime, sb.endtime, sb.entct, 
       sb.inact, sb.inadur, sb.inadist, 
       sb.smlct, sb.smldur, sb.smldist, 
       sb.larct, sb.lardur, sb.lardist, 
       sb.emptyct, sb.emptydur
FROM
(SELECT id, uid, location, animal, starttime, endtime, entct, 
       inact, inadur, inadist, 
       smlct, smldur, smldist, 
       larct, lardur, lardist, 
       emptyct, emptydur 
FROM tmp WHERE uid=x
GROUP BY location) as sb
ON DUPLICATE KEY UPDATE entct=sb.entct, inact=sb.inact, ...

auto refresh for every 5 mins

Refresh document every 300 seconds using HTML Meta tag add this inside the head tag of the page

 <meta http-equiv="refresh" content="300">

Using Script:

            setInterval(function() {
                  window.location.reload();
                }, 300000); 

Java: splitting the filename into a base and extension

Source: http://www.java2s.com/Code/Java/File-Input-Output/Getextensionpathandfilename.htm

such an utility class :

class Filename {
  private String fullPath;
  private char pathSeparator, extensionSeparator;

  public Filename(String str, char sep, char ext) {
    fullPath = str;
    pathSeparator = sep;
    extensionSeparator = ext;
  }

  public String extension() {
    int dot = fullPath.lastIndexOf(extensionSeparator);
    return fullPath.substring(dot + 1);
  }

  public String filename() { // gets filename without extension
    int dot = fullPath.lastIndexOf(extensionSeparator);
    int sep = fullPath.lastIndexOf(pathSeparator);
    return fullPath.substring(sep + 1, dot);
  }

  public String path() {
    int sep = fullPath.lastIndexOf(pathSeparator);
    return fullPath.substring(0, sep);
  }
}

usage:

public class FilenameDemo {
  public static void main(String[] args) {
    final String FPATH = "/home/mem/index.html";
    Filename myHomePage = new Filename(FPATH, '/', '.');
    System.out.println("Extension = " + myHomePage.extension());
    System.out.println("Filename = " + myHomePage.filename());
    System.out.println("Path = " + myHomePage.path());
  }
}

Format Float to n decimal places

Kinda surprised nobody's pointed out the direct way to do it, which is easy enough.

double roundToDecimalPlaces(double value, int decimalPlaces)
{
      double shift = Math.pow(10,decimalPlaces);
      return Math.round(value*shift)/shift;
}

Pretty sure this does not do half-even rounding though.

For what it's worth, half-even rounding is going to be chaotic and unpredictable any time you mix binary-based floating-point values with base-10 arithmetic. I'm pretty sure it cannot be done. The basic problem is that a value like 1.105 cannot be represented exactly in floating point. The floating point value is going to be something like 1.105000000000001, or 1.104999999999999. So any attempt to perform half-even rounding is going trip up on representational encoding errors.

IEEE floating point implementations will do half-rounding, but they do binary half-rounding, not decimal half-rounding. So you're probably ok

How to implement static class member functions in *.cpp file?

@crobar, you are right that there is a dearth of multi-file examples, so I decided to share the following in the hopes that it helps others:

::::::::::::::
main.cpp
::::::::::::::

#include <iostream>

#include "UseSomething.h"
#include "Something.h"

int main()
{
    UseSomething y;
    std::cout << y.getValue() << '\n';
}

::::::::::::::
Something.h
::::::::::::::

#ifndef SOMETHING_H_
#define SOMETHING_H_

class Something
{
private:
    static int s_value;
public:
    static int getValue() { return s_value; } // static member function
};
#endif

::::::::::::::
Something.cpp
::::::::::::::

#include "Something.h"

int Something::s_value = 1; // initializer

::::::::::::::
UseSomething.h
::::::::::::::

#ifndef USESOMETHING_H_
#define USESOMETHING_H_

class UseSomething
{
public:
    int getValue();
};

#endif

::::::::::::::
UseSomething.cpp
::::::::::::::

#include "UseSomething.h"
#include "Something.h"

int UseSomething::getValue()
{
    return(Something::getValue());
}

What is JSONP, and why was it created?

The great answers have already been given, I just need to give my piece in the form of code blocks in javascript (I will also include more modern and better solution for cross-origin requests: CORS with HTTP Headers):

JSONP:

1.client_jsonp.js

$.ajax({
    url: "http://api_test_server.proudlygeek.c9.io/?callback=?",
    dataType: "jsonp",
    success: function(data) {
        console.log(data);    
    }
});??????????????????

2.server_jsonp.js

var http = require("http"),
    url  = require("url");

var server = http.createServer(function(req, res) {

    var callback = url.parse(req.url, true).query.callback || "myCallback";
    console.log(url.parse(req.url, true).query.callback);

    var data = {
        'name': "Gianpiero",
        'last': "Fiorelli",
        'age': 37
    };

    data = callback + '(' + JSON.stringify(data) + ');';

    res.writeHead(200, {'Content-Type': 'application/json'});
    res.end(data);
});

server.listen(process.env.PORT, process.env.IP);

console.log('Server running at '  + process.env.PORT + ':' + process.env.IP);

CORS:

3.client_cors.js

$.ajax({
    url: "http://api_test_server.proudlygeek.c9.io/",
    success: function(data) {
        console.log(data);    
    }
});?

4.server_cors.js

var http = require("http"),
    url  = require("url");

var server = http.createServer(function(req, res) {
    console.log(req.headers);

    var data = {
        'name': "Gianpiero",
        'last': "Fiorelli",
        'age': 37
    };

    res.writeHead(200, {
        'Content-Type': 'application/json',
        'Access-Control-Allow-Origin': '*'
    });

    res.end(JSON.stringify(data));
});

server.listen(process.env.PORT, process.env.IP);

console.log('Server running at '  + process.env.PORT + ':' + process.env.IP);

Error: free(): invalid next size (fast):

If you are trying to allocate space for an array of pointers, such as

char** my_array_of_strings;  // or some array of pointers such as int** or even void**

then you will need to consider word size (8 bytes in a 64-bit system, 4 bytes in a 32-bit system) when allocating space for n pointers. The size of a pointer is the same of your word size.

So while you may wish to allocate space for n pointers, you are actually going to need n times 8 or 4 (for 64-bit or 32-bit systems, respectively)

To avoid overflowing your allocated memory for n elements of 8 bytes:

my_array_of_strings = (char**) malloc( n * 8 );  // for 64-bit systems
my_array_of_strings = (char**) malloc( n * 4 );  // for 32-bit systems

This will return a block of n pointers, each consisting of 8 bytes (or 4 bytes if you're using a 32-bit system)

I have noticed that Linux will allow you to use all n pointers when you haven't compensated for word size, but when you try to free that memory it realizes its mistake and it gives out that rather nasty error. And it is a bad one, when you overflow allocated memory, many security issues lie in wait.

Converting Secret Key into a String and Vice Versa

try this, it's work without Base64 ( that is included only in JDK 1.8 ), this code run also in the previous java version :)

private static String SK = "Secret Key in HEX";


//  To Encrupt

public static String encrypt( String Message ) throws Exception{

    byte[] KeyByte = hexStringToByteArray( SK);
    SecretKey k = new SecretKeySpec(KeyByte, 0, KeyByte.length, "DES");

    Cipher c = Cipher.getInstance("DES","SunJCE");
    c.init(1, k);
    byte mes_encrypted[] = cipher.doFinal(Message.getBytes());

    String MessageEncrypted = byteArrayToHexString(mes_encrypted);
    return MessageEncrypted;
}

//  To Decrypt

public static String decrypt( String MessageEncrypted )throws Exception{

    byte[] KeyByte = hexStringToByteArray( SK );
    SecretKey k = new SecretKeySpec(KeyByte, 0, KeyByte.length, "DES");

    Cipher dcr =  Cipher.getInstance("DES","SunJCE");
    dc.init(Cipher.DECRYPT_MODE, k);
    byte[] MesByte  = hexStringToByteArray( MessageEncrypted );
    byte mes_decrypted[] = dcipher.doFinal( MesByte );
    String MessageDecrypeted = new String(mes_decrypted);

    return MessageDecrypeted;
}

public static String byteArrayToHexString(byte bytes[]){

    StringBuffer hexDump = new StringBuffer();
    for(int i = 0; i < bytes.length; i++){
    if(bytes[i] < 0)
    {   
        hexDump.append(getDoubleHexValue(Integer.toHexString(256 - Math.abs(bytes[i]))).toUpperCase());
    }else
    {
        hexDump.append(getDoubleHexValue(Integer.toHexString(bytes[i])).toUpperCase());
    }
    return hexDump.toString();

}



public static byte[] hexStringToByteArray(String s) {

    int len = s.length();
    byte[] data = new byte[len / 2];
    for (int i = 0; i < len; i += 2)
    {   
        data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4) + Character.digit(s.charAt(i+1), 16));
    }
    return data;

} 

Adding values to an array in java

I suggest you step through the code in your debugger as debugging programs is what it is for.

What I would expect you would see is that every time the code loops int x = 0; is set.

Can I dispatch an action in reducer?

Starting another dispatch before your reducer is finished is an anti-pattern, because the state you received at the beginning of your reducer will not be the current application state anymore when your reducer finishes. But scheduling another dispatch from within a reducer is NOT an anti-pattern. In fact, that is what the Elm language does, and as you know Redux is an attempt to bring the Elm architecture to JavaScript.

Here is a middleware that will add the property asyncDispatch to all of your actions. When your reducer has finished and returned the new application state, asyncDispatch will trigger store.dispatch with whatever action you give to it.

// This middleware will just add the property "async dispatch" to all actions
const asyncDispatchMiddleware = store => next => action => {
  let syncActivityFinished = false;
  let actionQueue = [];

  function flushQueue() {
    actionQueue.forEach(a => store.dispatch(a)); // flush queue
    actionQueue = [];
  }

  function asyncDispatch(asyncAction) {
    actionQueue = actionQueue.concat([asyncAction]);

    if (syncActivityFinished) {
      flushQueue();
    }
  }

  const actionWithAsyncDispatch =
    Object.assign({}, action, { asyncDispatch });

  const res = next(actionWithAsyncDispatch);

  syncActivityFinished = true;
  flushQueue();

  return res;
};

Now your reducer can do this:

function reducer(state, action) {
  switch (action.type) {
    case "fetch-start":
      fetch('wwww.example.com')
        .then(r => r.json())
        .then(r => action.asyncDispatch({ type: "fetch-response", value: r }))
      return state;

    case "fetch-response":
      return Object.assign({}, state, { whatever: action.value });;
  }
}

mysql is not recognised as an internal or external command,operable program or batch

In my case, it turned out to be a simple case of spacing.

Turns out, i had a space inserted after the last ; and before ""C:\Program Files\MySQL\MySQL Server 5.7" For this very simple reason, no matter what i did, MySql was still not being recognized.

Once i eliminated the spaces before and after path, it worked perfectly.

In retrospect, seems like a very obvious answer, but nobody's mentioned it anywhere.

Also, i'm new to this whole windows thing, so please excuse me if it sounds very simple.

Use stored procedure to insert some data into a table

If you have the table definition to have an IDENTITY column e.g. IDENTITY(1,1) then don't include MyId in your INSERT INTO statement. The point of IDENTITY is it gives it the next unused value as the primary key value.

insert into MYDB.dbo.MainTable (MyFirstName, MyLastName, MyAddress, MyPort)
values(@myFirstName, @myLastName, @myAddress, @myPort)

There is then no need to pass the @MyId parameter into your stored procedure either. So change it to:

CREATE PROCEDURE [dbo].[sp_Test]
@myFirstName nvarchar(50)
,@myLastName nvarchar(50)
,@myAddress nvarchar(MAX)
,@myPort int

AS 

If you want to know what the ID of the newly inserted record is add

SELECT @@IDENTITY

to the end of your procedure. e.g. http://msdn.microsoft.com/en-us/library/ms187342.aspx

You will then be able to pick this up in which ever way you are calling it be it SQL or .NET.

P.s. a better way to show you table definision would have been to script the table and paste the text into your stackoverflow browser window because your screen shot is missing the column properties part where IDENTITY is set via the GUI. To do that right click the table 'Script Table as' --> 'CREATE to' --> Clipboard. You can also do File or New Query Editor Window (all self explanitory) experient and see what you get.

Access denied for user 'root'@'localhost' (using password: Yes) after password reset LINUX

Maybe the current user is not root,try sudo mysql -uroot -p ,I successed just now.

Where does mysql store data?

From here:

Windows

  1. Locate the my.ini, which store in the MySQL installation folder.

For Example, C:\Program Files\MySQL\MySQL Server 5.1\my.ini

  1. Open the “my.ini” with our favor text editor.
#Path to installation directory. All paths are usually resolved relative to this.
basedir="C:/Program Files/MySQL/MySQL Server 5.1/"
 
#Path to the database root
datadir="C:/Documents and Settings/All Users/Application Data/MySQL/MySQL Server 5.1/Data/"

Find the “datadir”, this is the where does MySQL stored the data in Windows.


Linux

  1. Locate the my.cnf with the find / -name my.cnf command.
yongmo@myserver:~$ find / -name my.cnf
find: /home/lost+found: Permission denied
find: /lost+found: Permission denied
/etc/mysql/my.cnf
  1. View the my.cnf file like this: cat /etc/mysql/my.cnf
yongmo@myserver:~$ cat /etc/mysql/my.cnf
#
# The MySQL database server configuration file.
#
# You can copy this to one of:
# - "/etc/mysql/my.cnf" to set global options,
# - "~/.my.cnf" to set user-specific options.
# 
[mysqld]
#
# * Basic Settings
#
user   = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket  = /var/run/mysqld/mysqld.sock
port   = 3306
basedir  = /usr
datadir  = /var/lib/mysql
tmpdir  = /tmp
language = /usr/share/mysql/english
skip-external-locking
  1. Find the “datadir”, this is where does MySQL stored the data in Linux system.

What is the difference between Select and Project Operations

select just changes cardinality of the result table but project does change both degree of relation and cardinality.

Escape quotes in JavaScript

Please find in the below code which escapes the single quotes as part of the entered string using a regular expression. It validates if the user-entered string is comma-separated and at the same time it even escapes any single quote(s) entered as part of the string.

In order to escape single quotes, just enter a backward slash followed by a single quote like: \’ as part of the string. I used jQuery validator for this example, and you can use as per your convenience.

Valid String Examples:

'Hello'

'Hello', 'World'

'Hello','World'

'Hello','World',' '

'It\'s my world', 'Can\'t enjoy this without me.', 'Welcome, Guest'

HTML:

<tr>
    <td>
        <label class="control-label">
            String Field:
        </label>
        <div class="inner-addon right-addon">
            <input type="text" id="stringField"
                   name="stringField"
                   class="form-control"
                   autocomplete="off"
                   data-rule-required="true"
                   data-msg-required="Cannot be blank."
                   data-rule-commaSeparatedText="true"
                   data-msg-commaSeparatedText="Invalid comma separated value(s).">
        </div>
    </td>

JavaScript:

     /**
 *
 * @param {type} param1
 * @param {type} param2
 * @param {type} param3
 */
jQuery.validator.addMethod('commaSeparatedText', function(value, element) {

    if (value.length === 0) {
        return true;
    }
    var expression = new RegExp("^((')([^\'\\\\]*(?:\\\\.[^\'\\\\])*)[\\w\\s,\\.\\-_\\[\\]\\)\\(]+([^\'\\\\]*(?:\\\\.[^\'\\\\])*)('))(((,)|(,\\s))(')([^\'\\\\]*(?:\\\\.[^\'\\\\])*)[\\w\\s,\\.\\-_\\[\\]\\)\\(]+([^\'\\\\]*(?:\\\\.[^\'\\\\])*)('))*$");
    return expression.test(value);
}, 'Invalid comma separated string values.');

Convert object of any type to JObject with Json.NET

This will work:

var cycles = cycleSource.AllCycles();

var settings = new JsonSerializerSettings
{
    ContractResolver = new CamelCasePropertyNamesContractResolver()
};

var vm = new JArray();

foreach (var cycle in cycles)
{
    var cycleJson = JObject.FromObject(cycle);
    // extend cycleJson ......
    vm.Add(cycleJson);
}

return vm;

Dataset - Vehicle make/model/year (free)

Apparently there is not much out there. And a lot of doubt that someone would be willing to provide such a repository. So I solved the problem myself, and am sharing my dataset with anyone else who finds themselves facing the same problem.

https://github.com/n8barr/automotive-model-year-data

Get the position of a div/span tag

This function will tell you the x,y position of the element relative to the page. Basically you have to loop up through all the element's parents and add their offsets together.

function getPos(el) {
    // yay readability
    for (var lx=0, ly=0;
         el != null;
         lx += el.offsetLeft, ly += el.offsetTop, el = el.offsetParent);
    return {x: lx,y: ly};
}

However, if you just wanted the x,y position of the element relative to its container, then all you need is:

var x = el.offsetLeft, y = el.offsetTop;

To put an element directly below this one, you'll also need to know its height. This is stored in the offsetHeight/offsetWidth property.

var yPositionOfNewElement = el.offsetTop + el.offsetHeight + someMargin;

Linux command to translate DomainName to IP

Use this

$ dig +short stackoverflow.com

69.59.196.211

or this

$ host stackoverflow.com

stackoverflow.com has address 69.59.196.211
stackoverflow.com mail is handled by 30 alt2.aspmx.l.google.com.
stackoverflow.com mail is handled by 40 aspmx2.googlemail.com.
stackoverflow.com mail is handled by 50 aspmx3.googlemail.com.
stackoverflow.com mail is handled by 10 aspmx.l.google.com.
stackoverflow.com mail is handled by 20 alt1.aspmx.l.google.com.

Python, remove all non-alphabet chars from string

You can use the re.sub() function to remove these characters:

>>> import re
>>> re.sub("[^a-zA-Z]+", "", "ABC12abc345def")
'ABCabcdef'

re.sub(MATCH PATTERN, REPLACE STRING, STRING TO SEARCH)

  • "[^a-zA-Z]+" - look for any group of characters that are NOT a-zA-z.
  • "" - Replace the matched characters with ""

Carriage Return\Line feed in Java

Encapsulate your writer to provide char replacement, like this:

public class WindowsFileWriter extends Writer {

    private Writer writer;

    public WindowsFileWriter(File file) throws IOException {
        try {
            writer = new OutputStreamWriter(new FileOutputStream(file), "ISO-8859-15");
        } catch (UnsupportedEncodingException e) {
            writer = new FileWriter(logfile);
        }
    }

    @Override
    public void write(char[] cbuf, int off, int len) throws IOException {
        writer.write(new String(cbuf, off, len).replace("\n", "\r\n"));
    }

    @Override
    public void flush() throws IOException {
        writer.flush();
    }

    @Override
    public void close() throws IOException {
        writer.close();
    }

}

How do I update Homebrew?

  • cd /usr/local
  • git status
  • Discard all the changes (unless you actually want to try to commit to Homebrew - you probably don't)
  • git status til it's clean
  • brew update

How to plot an array in python?

if you give a 2D array to the plot function of matplotlib it will assume the columns to be lines:

If x and/or y is 2-dimensional, then the corresponding columns will be plotted.

In your case your shape is not accepted (100, 1, 1, 8000). As so you can using numpy squeeze to solve the problem quickly:

np.squeez doc: Remove single-dimensional entries from the shape of an array.

import numpy as np
import matplotlib.pyplot as plt

data = np.random.randint(3, 7, (10, 1, 1, 80))
newdata = np.squeeze(data) # Shape is now: (10, 80)
plt.plot(newdata) # plotting by columns
plt.show()

But notice that 100 sets of 80 000 points is a lot of data for matplotlib. I would recommend that you look for an alternative. The result of the code example (run in Jupyter) is:

Jupyter matplotlib plot

What characters are valid in a URL?

All the gory details can be found in the current RFC on the topic: RFC 3986 (Uniform Resource Identifier (URI): Generic Syntax)

Based on this related answer, you are looking at a list that looks like: A-Z, a-z, 0-9, -, ., _, ~, :, /, ?, #, [, ], @, !, $, &, ', (, ), *, +, ,, ;, %, and =. Everything else must be url-encoded. Also, some of these characters can only exist in very specific spots in a URI and outside of those spots must be url-encoded (e.g. % can only be used in conjunction with url encoding as in %20), the RFC has all of these specifics.

Position last flex item at the end of container

This flexbox principle also works horizontally

During calculations of flex bases and flexible lengths, auto margins are treated as 0.
Prior to alignment via justify-content and align-self, any positive free space is distributed to auto margins in that dimension.

Setting an automatic left margin for the Last Item will do the work.

.last-item {
  margin-left: auto;
}

Code Example:

_x000D_
_x000D_
.container {_x000D_
  display: flex;_x000D_
  width: 400px;_x000D_
  outline: 1px solid black;_x000D_
}_x000D_
_x000D_
p {_x000D_
  height: 50px;_x000D_
  width: 50px;_x000D_
  margin: 5px;_x000D_
  background-color: blue;_x000D_
}_x000D_
_x000D_
.last-item {_x000D_
  margin-left: auto;_x000D_
}
_x000D_
<div class="container">_x000D_
  <p></p>_x000D_
  <p></p>_x000D_
  <p></p>_x000D_
  <p class="last-item"></p>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Codepen Snippet

This can be very useful for Desktop Footers.

As Envato did here with the company logo.

Codepen Snippet

"FATAL: Module not found error" using modprobe

i think there should be entry of your your_module.ko in /lib/modules/uname -r/modules.dep and in /lib/modules/uname -r/modules.dep.bin for "modprobe your_module" command to work

Copy the entire contents of a directory in C#

Better than any code (extension method to DirectoryInfo with recursion)

public static bool CopyTo(this DirectoryInfo source, string destination)
    {
        try
        {
            foreach (string dirPath in Directory.GetDirectories(source.FullName))
            {
                var newDirPath = dirPath.Replace(source.FullName, destination);
                Directory.CreateDirectory(newDirPath);
                new DirectoryInfo(dirPath).CopyTo(newDirPath);
            }
            //Copy all the files & Replaces any files with the same name
            foreach (string filePath in Directory.GetFiles(source.FullName))
            {
                File.Copy(filePath, filePath.Replace(source.FullName,destination), true);
            }
            return true;
        }
        catch (IOException exp)
        {
            return false;
        }
    }

Calling jQuery method from onClick attribute in HTML

I know this was answered long ago, but if you don't mind creating the button dynamically, this works using only the jQuery framework:

_x000D_
_x000D_
$(document).ready(function() {_x000D_
  $button = $('<input id="1" type="button" value="ahaha" />');_x000D_
  $('body').append($button);_x000D_
  $button.click(function() {_x000D_
    console.log("Id clicked: " + this.id ); // or $(this) or $button_x000D_
  });_x000D_
});
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
_x000D_
<p>And here is my HTML page:</p>_x000D_
_x000D_
<div class="Title">Welcome!</div>
_x000D_
_x000D_
_x000D_

Angular 4: How to include Bootstrap?

Run the following command in your project i.e npm install [email protected] --save

After installing the above dependency run the following npm command which will install the bootstrap module npm install --save @ng-bootstrap/ng-bootstrap

Check this out for the reference - https://github.com/ng-bootstrap/ng-bootstrap

Add the following import into app.module import {NgbModule} from '@ng-bootstrap/ng-bootstrap'; and add NgbModule to the imports

In your stye.css @import "../node_modules/bootstrap/dist/css/bootstrap.min.css";

Selecting a Linux I/O Scheduler

You can set this at boot by adding the "elevator" parameter to the kernel cmdline (such as in grub.cfg)

Example:

elevator=deadline

This will make "deadline" the default I/O scheduler for all block devices.

If you'd like to query or change the scheduler after the system has booted, or would like to use a different scheduler for a specific block device, I recommend installing and use the tool ioschedset to make this easy.

https://github.com/kata198/ioschedset

If you're on Archlinux it's available in aur:

https://aur.archlinux.org/packages/ioschedset

Some example usage:

# Get i/o scheduler for all block devices
[username@hostname ~]$ io-get-sched
sda:    bfq
sr0:    bfq

# Query available I/O schedulers
[username@hostname ~]$ io-set-sched --list
mq-deadline kyber bfq none

# Set sda to use "kyber"
[username@hostname ~]$ io-set-sched kyber /dev/sda
Must be root to set IO Scheduler. Rerunning under sudo...

[sudo] password for username:
+ Successfully set sda to 'kyber'!

# Get i/o scheduler for all block devices to assert change
[username@hostname ~]$ io-get-sched
sda:    kyber
sr0:    bfq

# Set all block devices to use 'deadline' i/o scheduler
[username@hostname ~]$ io-set-sched deadline
Must be root to set IO Scheduler. Rerunning under sudo...

+ Successfully set sda to 'deadline'!
+ Successfully set sr0 to 'deadline'!

# Get the current block scheduler just for sda
[username@hostname ~]$ io-get-sched sda
sda:    mq-deadline

Usage should be self-explanatory. The tools are standalone and only require bash.

Hope this helps!

EDIT: Disclaimer, these are scripts I wrote.

What could cause an error related to npm not being able to find a file? No contents in my node_modules subfolder. Why is that?

I had the SAME issue today and it was driving me nuts!!! What I had done was upgrade to node 8.10 and upgrade my NPM to the latest I uninstalled angular CLI

npm uninstall -g angular-cli
npm uninstall --save-dev angular-cli

I then verified my Cache from NPM if it wasn't up to date I cleaned it and ran the install again if npm version is < 5 then use npm cache clean --force

npm install -g @angular/cli@latest

and created a new project file and create a new angular project.

How do I right align div elements?

You can use flexbox with flex-grow to push the last element to the right.

<div style="display: flex;">
  <div style="flex-grow: 1;">Left</div>
  <div>Right</div>
</div>

ip address validation in python using regex

Why not use a library function to validate the ip address?

>>> ip="241.1.1.112343434" 
>>> socket.inet_aton(ip)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
socket.error: illegal IP address string passed to inet_aton

How to count lines in a document?

wc -l <file.txt>

Or

command | wc -l

how to download file in react js

browsers are smart enough to detect the link and downloading it directly when clicking on an anchor tag without using the download attribute.

after getting your file link from the api, just use plain javascript by creating anchor tag and delete it after clicking on it dynamically immediately on the fly.

const link = document.createElement('a');
link.href = `your_link.pdf`;
document.body.appendChild(link);
link.click();
document.body.removeChild(link);

How do I get next month date from today's date and insert it in my database?

You can use PHP's strtotime() function:

// One month from today
$date = date('Y-m-d', strtotime('+1 month'));

// One month from a specific date
$date = date('Y-m-d', strtotime('+1 month', strtotime('2015-01-01')));

Just note that +1 month is not always calculated intuitively. It appears to always add the number of days that exist in the current month.

Current Date  | +1 month
-----------------------------------------------------
2015-01-01    | 2015-02-01   (+31 days)
2015-01-15    | 2015-02-15   (+31 days)
2015-01-30    | 2015-03-02   (+31 days, skips Feb)
2015-01-31    | 2015-03-03   (+31 days, skips Feb)
2015-02-15    | 2015-03-15   (+28 days)
2015-03-31    | 2015-05-01   (+31 days, skips April)
2015-12-31    | 2016-01-31   (+31 days)

Some other date/time intervals that you can use:

$date = date('Y-m-d'); // Initial date string to use in calculation

$date = date('Y-m-d', strtotime('+1 day', strtotime($date)));
$date = date('Y-m-d', strtotime('+1 week', strtotime($date)));
$date = date('Y-m-d', strtotime('+2 week', strtotime($date)));
$date = date('Y-m-d', strtotime('+1 month', strtotime($date)));
$date = date('Y-m-d', strtotime('+30 days', strtotime($date)));

Giving multiple conditions in for loop in Java

You can also use "or" operator,

for( int i = 0 ; i < 100 || someOtherCondition() ; i++ ) {
  ...
}

Why does GitHub recommend HTTPS over SSH?

GitHub have changed their recommendation several times (example).

It appears that they currently recommend HTTPS because it is the easiest to set up on the widest range of networks and platforms, and by users who are new to all this.

There is no inherent flaw in SSH (if there was they would disable it) -- in the links below, you will see that they still provide details about SSH connections too:

  1. HTTPS is less likely to be blocked by a firewall.

    https://help.github.com/articles/which-remote-url-should-i-use/

    The https:// clone URLs are available on all repositories, public and private. These URLs work everywhere--even if you are behind a firewall or proxy.

  2. An HTTPS connection allows credential.helper to cache your password.

    https://help.github.com/articles/set-up-git

    Good to know: The credential helper only works when you clone an HTTPS repo URL. If you use the SSH repo URL instead, SSH keys are used for authentication. While we do not recommend it, if you wish to use this method, check out this guide for help generating and using an SSH key.

Spring MVC Missing URI template variable

This error may happen when mapping variables you defined in REST definition do not match with @PathVariable names.

Example: Suppose you defined in the REST definition

@GetMapping(value = "/{appId}", produces = "application/json", consumes = "application/json")

Then during the definition of the function, it should be

public ResponseEntity<List> getData(@PathVariable String appId)

This error may occur when you use any other variable other than defined in the REST controller definition with @PathVariable. Like, the below code will raise the error as ID is different than appId variable name:

public ResponseEntity<List> getData(@PathVariable String ID)

Server.MapPath("."), Server.MapPath("~"), Server.MapPath(@"\"), Server.MapPath("/"). What is the difference?

Server.MapPath specifies the relative or virtual path to map to a physical directory.

  • Server.MapPath(".")1 returns the current physical directory of the file (e.g. aspx) being executed
  • Server.MapPath("..") returns the parent directory
  • Server.MapPath("~") returns the physical path to the root of the application
  • Server.MapPath("/") returns the physical path to the root of the domain name (is not necessarily the same as the root of the application)

An example:

Let's say you pointed a web site application (http://www.example.com/) to

C:\Inetpub\wwwroot

and installed your shop application (sub web as virtual directory in IIS, marked as application) in

D:\WebApps\shop

For example, if you call Server.MapPath() in following request:

http://www.example.com/shop/products/GetProduct.aspx?id=2342

then:

  • Server.MapPath(".")1 returns D:\WebApps\shop\products
  • Server.MapPath("..") returns D:\WebApps\shop
  • Server.MapPath("~") returns D:\WebApps\shop
  • Server.MapPath("/") returns C:\Inetpub\wwwroot
  • Server.MapPath("/shop") returns D:\WebApps\shop

If Path starts with either a forward slash (/) or backward slash (\), the MapPath() returns a path as if Path was a full, virtual path.

If Path doesn't start with a slash, the MapPath() returns a path relative to the directory of the request being processed.

Note: in C#, @ is the verbatim literal string operator meaning that the string should be used "as is" and not be processed for escape sequences.

Footnotes

  1. Server.MapPath(null) and Server.MapPath("") will produce this effect too.

(unicode error) 'unicodeescape' codec can't decode bytes in position 2-3: truncated \UXXXXXXXX escape

This error occurs because you are using a normal string as a path. You can use one of the three following solutions to fix your problem:

1: Just put r before your normal string it converts normal string to raw string:

pandas.read_csv(r"C:\Users\DeePak\Desktop\myac.csv")

2:

pandas.read_csv("C:/Users/DeePak/Desktop/myac.csv")

3:

pandas.read_csv("C:\\Users\\DeePak\\Desktop\\myac.csv")

Automate scp file transfer using a shell script

#!/usr/bin/expect -f

# connect via scp
spawn scp "[email protected]:/home/santhosh/file.dmp" /u01/dumps/file.dmp
#######################
expect {
  -re ".*es.*o.*" {
    exp_send "yes\r"
    exp_continue
  }
  -re ".*sword.*" {
    exp_send "PASSWORD\r"
  }
}
interact

http://blogs.oracle.com/SanthoshK/entry/automate_linux_scp_command

Converting date between DD/MM/YYYY and YYYY-MM-DD?

Your example code is wrong. This works:

import datetime

datetime.datetime.strptime("21/12/2008", "%d/%m/%Y").strftime("%Y-%m-%d")

The call to strptime() parses the first argument according to the format specified in the second, so those two need to match. Then you can call strftime() to format the result into the desired final format.

In React Native, how do I put a view on top of another view, with part of it lying outside the bounds of the view behind?

import React, {Component} from 'react';
import {StyleSheet, View} from 'react-native';


export default class App extends Component {
  render() {
    return (
       <View>// you need to wrap the two Views an another View
          <View style={styles.box1}></View>
          <View style={styles.box2}></View>
       </View> 
    );
  }
}

const styles = StyleSheet.create({
  box1:{
    height:100,
    width:100,
    backgroundColor:'red'
  },
  box2:{
    height:100,
    width:100,
    backgroundColor:'green',
    position: 'absolute',
    top:10,
    left:30

  },
});

java.sql.SQLException Parameter index out of range (1 > number of parameters, which is 0)

You will get this error when you call any of the setXxx() methods on PreparedStatement, while the SQL query string does not have any placeholders ? for this.

For example this is wrong:

String sql = "INSERT INTO tablename (col1, col2, col3) VALUES (val1, val2, val3)";
// ...

preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, val1); // Fail.
preparedStatement.setString(2, val2);
preparedStatement.setString(3, val3);

You need to fix the SQL query string accordingly to specify the placeholders.

String sql = "INSERT INTO tablename (col1, col2, col3) VALUES (?, ?, ?)";
// ...

preparedStatement = connection.prepareStatement(sql);
preparedStatement.setString(1, val1);
preparedStatement.setString(2, val2);
preparedStatement.setString(3, val3);

Note the parameter index starts with 1 and that you do not need to quote those placeholders like so:

String sql = "INSERT INTO tablename (col1, col2, col3) VALUES ('?', '?', '?')";

Otherwise you will still get the same exception, because the SQL parser will then interpret them as the actual string values and thus can't find the placeholders anymore.

See also:

How to delete columns that contain ONLY NAs?

Another option with Filter

Filter(function(x) !all(is.na(x)), df)

NOTE: Data from @Simon O'Hanlon's post.

How can I position my div at the bottom of its container?

CSS Grid

Since the usage of CSS Grid is increasing, I would like to suggest align-self to the element that is inside a grid container.

align-self can contain any of the values: end, self-end, flex-end for the following example.

_x000D_
_x000D_
#parent {_x000D_
  display: grid;_x000D_
}_x000D_
_x000D_
#child1 {_x000D_
  align-self: end;_x000D_
}_x000D_
_x000D_
/* Extra Styling for Snippet */_x000D_
_x000D_
#parent {_x000D_
  height: 150px;_x000D_
  background: #5548B0;_x000D_
  color: #fff;_x000D_
  padding: 10px;_x000D_
  font-family: sans-serif;_x000D_
}_x000D_
_x000D_
#child1 {_x000D_
  height: 50px;_x000D_
  width: 50px;_x000D_
  background: #6A67CE;_x000D_
  text-align: center;_x000D_
  vertical-align: middle;_x000D_
  line-height: 50px;_x000D_
}
_x000D_
<div id="parent">_x000D_
  <!-- Other elements here -->_x000D_
  <div id="child1">_x000D_
    1_x000D_
  </div>_x000D_
_x000D_
</div>
_x000D_
_x000D_
_x000D_

Append values to query string

This is even more frustrating because now (.net 5) MS have marked many (all) of their methods that take a string instead of a Uri as obsolete.

Anyway, probably a better way to manipulate relative Uris is to give it what it wants:

var requestUri = new Uri("x://x").MakeRelativeUri(
   new UriBuilder("x://x") { Path = path, Query = query }.Uri);

You can use the other answers to actually build the query string.

Where to find htdocs in XAMPP Mac

for each easy and useful access you can add terminal command via editing your bash profile, here how:

open terminal -> type cd hit enter. then type nano .bash_profile then add this line alias htdocs="cd ~/.bitnami/stackman/machines/xampp/volumes/root/htdocs" Now hit ctrl + o then hit enter, then hit ctrl + x Now to refresh the terminal commands type the following command

source .bash_profile

Now you can use htdocs command each time you want to navigate htdocs folder.

Flask at first run: Do not use the development server in a production environment

The official tutorial discusses deploying an app to production. One option is to use Waitress, a production WSGI server. Other servers include Gunicorn and uWSGI.

When running publicly rather than in development, you should not use the built-in development server (flask run). The development server is provided by Werkzeug for convenience, but is not designed to be particularly efficient, stable, or secure.

Instead, use a production WSGI server. For example, to use Waitress, first install it in the virtual environment:

$ pip install waitress

You need to tell Waitress about your application, but it doesn’t use FLASK_APP like flask run does. You need to tell it to import and call the application factory to get an application object.

$ waitress-serve --call 'flaskr:create_app'
Serving on http://0.0.0.0:8080

Or you can use waitress.serve() in the code instead of using the CLI command.

from flask import Flask

app = Flask(__name__)

@app.route("/")
def index():
    return "<h1>Hello!</h1>"

if __name__ == "__main__":
    from waitress import serve
    serve(app, host="0.0.0.0", port=8080)
$ python hello.py

Where is shared_ptr?

If your'e looking bor boost's shared_ptr, you could have easily found the answer by googling shared_ptr, following the links to the docs, and pulling up a complete working example such as this.

In any case, here is a minimalistic complete working example for you which I just hacked up:

#include <boost/shared_ptr.hpp>

struct MyGizmo
{
    int n_;
};

int main()
{
    boost::shared_ptr<MyGizmo> p(new MyGizmo);
    return 0;
}

In order for the #include to find the header, the libraries obviously need to be in the search path. In MSVC, you set this in Project Settings>Configuration Properties>C/C++>Additional Include Directories. In my case, this is set to C:\Program Files (x86)\boost\boost_1_42

Can PHP cURL retrieve response headers AND body in a single request?

Try this if you are using GET:

$curl = curl_init($url);

curl_setopt_array($curl, array(
    CURLOPT_URL => $url,
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_ENCODING => "",
    CURLOPT_MAXREDIRS => 10,
    CURLOPT_TIMEOUT => 30,
    CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
    CURLOPT_CUSTOMREQUEST => "GET",
    CURLOPT_HTTPHEADER => array(
        "Cache-Control: no-cache"
    ),
));

$response = curl_exec($curl);
curl_close($curl);

Regex using javascript to return just numbers

For number with decimal fraction and minus sign, I use this snippet:

_x000D_
_x000D_
const NUMERIC_REGEXP = /[-]{0,1}[\d]*[.]{0,1}[\d]+/g;

const numbers = '2.2px 3.1px 4px -7.6px obj.key'.match(NUMERIC_REGEXP)

console.log(numbers); // ["2.2", "3.1", "4", "-7.6"]
_x000D_
_x000D_
_x000D_

Update: - 7/9/2018

Found a tool which allows you to edit regular expression visually: JavaScript Regular Expression Parser & Visualizer.

Update:

Here's another one with which you can even debugger regexp: Online regex tester and debugger.

Update:

Another one: RegExr.

Update:

Regexper and Regex Pal.

How do you show animated GIFs on a Windows Form (c#)

Public Class Form1

    Private animatedimage As New Bitmap("C:\MyData\Search.gif")
    Private currentlyanimating As Boolean = False

    Private Sub OnFrameChanged(ByVal sender As System.Object, ByVal e As System.EventArgs)

        Me.Invalidate()

    End Sub

    Private Sub AnimateImage()

        If currentlyanimating = True Then
            ImageAnimator.Animate(animatedimage, AddressOf Me.OnFrameChanged)
            currentlyanimating = False
        End If

    End Sub

    Protected Overrides Sub OnPaint(ByVal e As System.Windows.Forms.PaintEventArgs)

        AnimateImage()
        ImageAnimator.UpdateFrames(animatedimage)
        e.Graphics.DrawImage(animatedimage, New Point((Me.Width / 4) + 40, (Me.Height / 4) + 40))

    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        BtnStop.Enabled = False

    End Sub

    Private Sub BtnStop_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnStop.Click

        currentlyanimating = False
        ImageAnimator.StopAnimate(animatedimage, AddressOf Me.OnFrameChanged)
        BtnStart.Enabled = True
        BtnStop.Enabled = False

    End Sub

    Private Sub BtnStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnStart.Click

        currentlyanimating = True
        AnimateImage()
        BtnStart.Enabled = False
        BtnStop.Enabled = True

    End Sub

End Class

Converting dd/mm/yyyy formatted string to Datetime

You need to use DateTime.ParseExact with format "dd/MM/yyyy"

DateTime dt=DateTime.ParseExact("24/01/2013", "dd/MM/yyyy", CultureInfo.InvariantCulture);

Its safer if you use d/M/yyyy for the format, since that will handle both single digit and double digits day/month. But that really depends if you are expecting single/double digit values.


Your date format day/Month/Year might be an acceptable date format for some cultures. For example for Canadian Culture en-CA DateTime.Parse would work like:

DateTime dt = DateTime.Parse("24/01/2013", new CultureInfo("en-CA"));

Or

System.Threading.Thread.CurrentThread.CurrentCulture = new CultureInfo("en-CA");
DateTime dt = DateTime.Parse("24/01/2013"); //uses the current Thread's culture

Both the above lines would work because the the string's format is acceptable for en-CA culture. Since you are not supplying any culture to your DateTime.Parse call, your current culture is used for parsing which doesn't support the date format. Read more about it at DateTime.Parse.


Another method for parsing is using DateTime.TryParseExact

DateTime dt;
if (DateTime.TryParseExact("24/01/2013", 
                            "d/M/yyyy", 
                            CultureInfo.InvariantCulture, 
                            DateTimeStyles.None,
    out dt))
{
    //valid date
}
else
{
    //invalid date
}

The TryParse group of methods in .Net framework doesn't throw exception on invalid values, instead they return a bool value indicating success or failure in parsing.

Notice that I have used single d and M for day and month respectively. Single d and M works for both single/double digits day and month. So for the format d/M/yyyy valid values could be:

  • "24/01/2013"
  • "24/1/2013"
  • "4/12/2013" //4 December 2013
  • "04/12/2013"

For further reading you should see: Custom Date and Time Format Strings

define() vs. const

Most of these answers are wrong or are only telling half the story.

  1. You can scope your constants by using namespaces.
  2. You can use the "const" keyword outside of class definitions. However, just like in classes the values assigned using the "const" keyword must be constant expressions.

For example:

const AWESOME = 'Bob'; // Valid

Bad example:

const AWESOME = whatIsMyName(); // Invalid (Function call)
const WEAKNESS = 4+5+6; // Invalid (Arithmetic) 
const FOO = BAR . OF . SOAP; // Invalid (Concatenation)

To create variable constants use define() like so:

define('AWESOME', whatIsMyName()); // Valid
define('WEAKNESS', 4 + 5 + 6); // Valid
define('FOO', BAR . OF . SOAP); // Valid

Create new project on Android, Error: Studio Unknown host 'services.gradle.org'

Go to setting option which is on upper strip of android studio and follow the below steps to solve the problem.

setting > Appearance&behavior > HTTP and proxy > click on Auto detect Enable option.(The option with radio box)select this one...

Constructor in an Interface?

A problem that you get when you allow constructors in interfaces comes from the possibility to implement several interfaces at the same time. When a class implements several interfaces that define different constructors, the class would have to implement several constructors, each one satisfying only one interface, but not the others. It will be impossible to construct an object that calls each of these constructors.

Or in code:

interface Named { Named(String name); }
interface HasList { HasList(List list); }

class A implements Named, HasList {

  /** implements Named constructor.
   * This constructor should not be used from outside, 
   * because List parameter is missing
   */
  public A(String name)  { 
    ...
  }

  /** implements HasList constructor.
   * This constructor should not be used from outside, 
   * because String parameter is missing
   */
  public A(List list) {
    ...
  }

  /** This is the constructor that we would actually 
   * need to satisfy both interfaces at the same time
   */ 
  public A(String name, List list) {
    this(name);
    // the next line is illegal; you can only call one other super constructor
    this(list); 
  }
}

Phone number validation Android

val UserMobile = findViewById<edittext>(R.id.UserMobile)
val msgUserMobile: String = UserMobile.text.toString()
fun String.isMobileValid(): Boolean {
    // 11 digit number start with 011 or 010 or 015 or 012
    // then [0-9]{8} any numbers from 0 to 9 with length 8 numbers
    if(Pattern.matches("(011|012|010|015)[0-9]{8}", msgUserMobile)) {
        return true
    }
    return false
}

if(msgUserMobile.trim().length==11&& msgUserMobile.isMobileValid())
    {//pass}
else 
    {//not valid} 

Cannot connect to MySQL Workbench on mac. Can't connect to MySQL server on '127.0.0.1' (61) Mac Macintosh

There may be one or multiple reasons if you are not able to connect to MAC OS X MySQL server with MySQL-workbench.

When you press 'test connection' you might see this error. This could be explained briefly if you go step by step through 'Configure server management..' On the basis of the red crosses you can filter out the real problem.

The most common problems are associated with the installation of MySQL-server. Few people either forget to install the server prior to installing MySQL-workbench. Some others would install a part of the product. Please check whether you have also installed all the 3 parts that comes with the MySQL-Server dmg(disk image) file which contains mysql-server package. Those 3 parts are: MySQL server, preference pane and startup item.

Note: If you haven't selected preference pane then you won't be able to start mysql server instance from the System preferences.

After you make sure that you have installed each item then you can check server instance of your native mysql-server. Open System preferences from dock and click MySQL. Then click Start MySQL Server to start the server instance. If the server instance is stopped, then MySQL-workbench won't be able to connect to the MySQL server.

If you are still facing issue, then you need to check the port of the connection which you are making. Default port is '3307' and NOT '3306'. You can check it with using the following command in mysql terminal:

SHOW GLOBAL VARIABLES LIKE 'PORT';

Please note that this process helps you to connect to the local instance. If you have to connect to a remote server, then you have to enter that specific IP and Port. Contact your server's administrator if you are facing the issue. As this question specifically states that the problem is related to connecting to the local instance, I am not writing checks that you may need to ensure.

How to make Bootstrap carousel slider use mobile left/right swipe

With bootstrap 4.2 its now very easy, you just need to pass the touch option in the carousel div as data-touch="true", as it accepts Boolean value only.

As in your case update bootstrap to 4.2 and paste(Or download source files) the following in exact order :

    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
    <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.7/umd/popper.min.js" integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1" crossorigin="anonymous"></script>
    <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/js/bootstrap.min.js" integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM" crossorigin="anonymous"></script>

and then add the touch option in your bootstrap carousel div

    <div id="sidebar-carousel-1" class="carousel slide" data-ride="carousel" data-touch="true">

line breaks in a textarea

Some wrong answers are posted here. instead of replacing \n to <br />, they are replacing <br /> to \n

So here is a good answer to store <br /> in your mysql when you entered in textarea:

str_replace("\n", '<br />',  $textarea);

Powershell script to check if service is started, if not then start it

Combining Alaa Akoum and Nick Eagle's solutions allowed me to loop through a series of windows services and stop them if they're running.

# stop the following Windows services in the specified order:
[Array] $Services = 'Service1','Service2','Service3','Service4','Service5';

# loop through each service, if its running, stop it
foreach($ServiceName in $Services)
{
    $arrService = Get-Service -Name $ServiceName
    write-host $ServiceName
    while ($arrService.Status -eq 'Running')
    {
        Stop-Service $ServiceName
        write-host $arrService.status
        write-host 'Service stopping'
        Start-Sleep -seconds 60
        $arrService.Refresh()
        if ($arrService.Status -eq 'Stopped')
            {
              Write-Host 'Service is now Stopped'
            }
     }
 }

The same can be done to start a series of service if they are not running:

# start the following Windows services in the specified order:
[Array] $Services = 'Service1','Service2','Service3','Service4','Service5';

# loop through each service, if its not running, start it
foreach($ServiceName in $Services)
{
    $arrService = Get-Service -Name $ServiceName
    write-host $ServiceName
    while ($arrService.Status -ne 'Running')
    {
        Start-Service $ServiceName
        write-host $arrService.status
        write-host 'Service starting'
        Start-Sleep -seconds 60
        $arrService.Refresh()
        if ($arrService.Status -eq 'Running')
        {
          Write-Host 'Service is now Running'
        }
    }
}

Is there a way to get the source code from an APK file?

Apktool for reverse engineering 3rd party, closed, binary Android apps.

It can decode resources to nearly original form and rebuild them after making some modifications.

It makes possible to debug smali code step by step. Also it makes working with an app easier because of project-like file structure and automation of some repetitive tasks like building apk, etc.

http://ibotpeaches.github.io/Apktool/