Programs & Examples On #Qml

QML (Qt Modeling Language) is a declarative language that allows user interfaces to be described in terms of their visual components and how they interact and relate with one another. It is a highly readable language, JSON-like syntax with support for imperative JavaScript expressions combined with dynamic property bindings. It can be used to build fluid animated user interfaces that can be connected to any backend C++ libraries.

How can I add JAR files to the web-inf/lib folder in Eclipse?

Found a solution. This problem happens, when you import a project.

The solution is simple

  1. Right click -> Properties
  2. Project Facets -> Check Dyanmic Web Module and Java Version
  3. Apply Setting.

Now you should see the web app libraries showing your jars added.

Does Python have a toString() equivalent, and can I convert a db.Model element to String?

In python, the str() method is similar to the toString() method in other languages. It is called passing the object to convert to a string as a parameter. Internally it calls the __str__() method of the parameter object to get its string representation.

In this case, however, you are comparing a UserProperty author from the database, which is of type users.User with the nickname string. You will want to compare the nickname property of the author instead with todo.author.nickname in your template.

How to access at request attributes in JSP?

EL expression:

${requestScope.Error_Message}

There are several implicit objects in JSP EL. See Expression Language under the "Implicit Objects" heading.

How to increase storage for Android Emulator? (INSTALL_FAILED_INSUFFICIENT_STORAGE)

The following approach worked for me

  1. Navigate to your android SDK/tools folder in the terminal window (in case you didn't added the path for it)

  2. Make sure the virtual device you're planning to clean is powered off.

  3. Run the command "./emulator -wipe-data -avd YourAvdName" where YourAvdName is the name of your virtual android device

How to search in commit messages using command line?

git log --grep=<pattern>
    Limit the commits output to ones with log message that matches the 
    specified pattern (regular expression).

--git help log

How to send post request with x-www-form-urlencoded body

string urlParameters = "param1=value1&param2=value2";
string _endPointName = "your url post api";

var httpWebRequest = (HttpWebRequest)WebRequest.Create(_endPointName);

httpWebRequest.ContentType = "application/x-www-form-urlencoded";
httpWebRequest.Method = "POST";
httpWebRequest.Headers["ContentType"] = "application/x-www-form-urlencoded";

System.Net.ServicePointManager.ServerCertificateValidationCallback +=
                                                  (se, cert, chain, sslerror) =>
                                                  {
                                                      return true;
                                                  };


using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
                {
                    streamWriter.Write(urlParameters);
                    streamWriter.Flush();
                    streamWriter.Close();
                }
var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();

using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
                {
                    var result = streamReader.ReadToEnd();
                }

Assign variable in if condition statement, good practice or not?

I would consider this more of an old-school C style; it is not really good practice in JavaScript so you should avoid it.

SQL Server: combining multiple rows into one row

There are several methods.

If you want just the consolidated string value returned, this is a good quick and easy approach

DECLARE @combinedString VARCHAR(MAX)
SELECT @combinedString = COALESCE(@combinedString + ', ', '') + stringvalue
FROM jira.customfieldValue
WHERE customfield = 12534
    AND ISSUE = 19602

SELECT @combinedString as StringValue 

Which will return your combined string.

You can also try one of the XML methods e.g.

SELECT DISTINCT Issue, Customfield, StringValues
FROM Jira.customfieldvalue v1
CROSS APPLY ( SELECT StringValues + ',' 
              FROM jira.customfieldvalue v2
              WHERE v2.Customfield = v1.Customfield 
                  AND v2.Issue = v1.issue 
              ORDER BY ID 
                  FOR XML PATH('') )  D ( StringValues )
WHERE customfield = 12534
    AND ISSUE = 19602

How to remove "onclick" with JQuery?

What if onclick event is not directly on element, but from parent element? This should work:

$(".noclick").attr('onclick','').unbind('click');
$(".noclick").click(function(e){
    e.preventDefault();
    e.stopPropagation();
    return false;
});

Load json from local file with http.get() in angular 2

I you want to put the response of the request in the navItems. Because http.get() return an observable you will have to subscribe to it.

Look at this example:

_x000D_
_x000D_
// version without map_x000D_
this.http.get("../data/navItems.json")_x000D_
    .subscribe((success) => {_x000D_
      this.navItems = success.json();          _x000D_
    });_x000D_
_x000D_
// with map_x000D_
import 'rxjs/add/operator/map'_x000D_
this.http.get("../data/navItems.json")_x000D_
    .map((data) => {_x000D_
      return data.json();_x000D_
    })_x000D_
    .subscribe((success) => {_x000D_
      this.navItems = success;          _x000D_
    });
_x000D_
_x000D_
_x000D_

Convert string to Time

string Time = "16:23:01";
DateTime date = DateTime.Parse(Time, System.Globalization.CultureInfo.CurrentCulture);

string t = date.ToString("HH:mm:ss tt");

How do I edit $PATH (.bash_profile) on OSX?

For me my mac OS is Mojave. and I'm facing the same issue for three days and in the end, I just write the correct path in the .bash_profile file which is like this:

    export PATH=/Users/[YOURNAME]/development/flutter/bin:$PATH
  • note1: if u don't have .bash_profile create one and write the line above
  • note2: zip your downloaded flutter SDK in [home]/development if you copy and paste this path

How to change the button text of <input type="file" />?

Only CSS & bootstrap class

        <div class="col-md-4 input-group">
            <input class="form-control" type="text"/>
            <div class="input-group-btn">
                <label for="files" class="btn btn-default">browse</label>
                <input id="files" type="file" class="btn btn-default"  style="visibility:hidden;"/>
            </div>
        </div>

Add days to JavaScript Date

The mozilla docs for setDate() don't indicate that it will handle end of month scenarios. See https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/Date

setDate()

  • Sets the day of the month (1-31) for a specified date according to local time.

That is why I use setTime() when I need to add days.

Convert string to a variable name

strsplit to parse your input and, as Greg mentioned, assign to assign the variables.

original_string <- c("x=123", "y=456")
pairs <- strsplit(original_string, "=")
lapply(pairs, function(x) assign(x[1], as.numeric(x[2]), envir = globalenv()))
ls()

Detect click outside element

Can be solved nicely by setting up a custom directive once:

Vue.directive('click-outside', {
  bind () {
      this.event = event => this.vm.$emit(this.expression, event)
      this.el.addEventListener('click', this.stopProp)
      document.body.addEventListener('click', this.event)
  },   
  unbind() {
    this.el.removeEventListener('click', this.stopProp)
    document.body.removeEventListener('click', this.event)
  },

  stopProp(event) { event.stopPropagation() }
})

Usage:

<div v-click-outside="nameOfCustomEventToCall">
  Some content
</div>

In the component:

events: {
  nameOfCustomEventToCall: function (event) {
    // do something - probably hide the dropdown menu / modal etc.
  }
}

Working Demo on JSFiddle with additional info about caveats:

https://jsfiddle.net/Linusborg/yzm8t8jq/

Format an Excel column (or cell) as Text in C#?

I've recently battled with this problem as well, and I've learned two things about the above suggestions.

  1. Setting the numberFormatting to @ causes Excel to left-align the value, and read it as if it were text, however, it still truncates the leading zero.
  2. Adding an apostrophe at the beginning results in Excel treating it as text and retains the zero, and then applies the default text format, solving both problems.

The misleading aspect of this is that you now have a different value in the cell. Fortuately, when you copy/paste or export to CSV, the apostrophe is not included.

Conclusion: use the apostrophe, not the numberFormatting in order to retain the leading zeros.

How to change column datatype in SQL database without losing data

If it is a valid change.

you can change the property.

Tools --> Options --> Designers --> Table and Database designers --> Uncheck --> Prevent saving changes that required table re-creation.

Now you can easily change the column name without recreating the table or losing u r records.

Simple http post example in Objective-C?

From Apple's Official Website :

// In body data for the 'application/x-www-form-urlencoded' content type,
// form fields are separated by an ampersand. Note the absence of a
// leading ampersand.
NSString *bodyData = @"name=Jane+Doe&address=123+Main+St";

NSMutableURLRequest *postRequest = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"https://www.apple.com"]];

// Set the request's content type to application/x-www-form-urlencoded
[postRequest setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];

// Designate the request a POST request and specify its body data
[postRequest setHTTPMethod:@"POST"];
[postRequest setHTTPBody:[NSData dataWithBytes:[bodyData UTF8String] length:strlen([bodyData UTF8String])]];

// Initialize the NSURLConnection and proceed as described in
// Retrieving the Contents of a URL

From : code with chris

    // Create the request.
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://google.com"]];

// Specify that it will be a POST request
request.HTTPMethod = @"POST";

// This is how we set header fields
[request setValue:@"application/xml; charset=utf-8" forHTTPHeaderField:@"Content-Type"];

// Convert your data and set your request's HTTPBody property
NSString *stringData = @"some data";
NSData *requestBodyData = [stringData dataUsingEncoding:NSUTF8StringEncoding];
request.HTTPBody = requestBodyData;

// Create url connection and fire request
NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:request delegate:self];

React-Router open Link in new tab

You can use "{}" for the target, then jsx will not cry

<Link target={"_blank"} to="your-link">Your Link</Link>

Using DateTime in a SqlParameter for Stored Procedure, format error

Here is how I add parameters:

sprocCommand.Parameters.Add(New SqlParameter("@Date_Of_Birth",Data.SqlDbType.DateTime))
sprocCommand.Parameters("@Date_Of_Birth").Value = DOB

I am assuming when you write out DOB there are no quotes.

Are you using a third-party control to get the date? I have had problems with the way the text value is generated from some of them.

Lastly, does it work if you type in the .Value attribute of the parameter without referencing DOB?

After Spring Boot 2.0 migration: jdbcUrl is required with driverClassName

Configure Two DataSources in Spring Boot 2.0.* or above

If you need to configure multiple data sources, you have to mark one of the DataSource instances as @Primary, because various auto-configurations down the road expect to be able to get one by type.

If you create your own DataSource, the auto-configuration backs off. In the following example, we provide the exact same feature set as the auto-configuration provides on the primary data source:

@Bean
@Primary
@ConfigurationProperties("app.datasource.first")
public DataSourceProperties firstDataSourceProperties() {
    return new DataSourceProperties();
}

@Bean
@Primary
@ConfigurationProperties("app.datasource.first")
public DataSource firstDataSource() {
    return firstDataSourceProperties().initializeDataSourceBuilder().build();
}

@Bean
@ConfigurationProperties("app.datasource.second")
public BasicDataSource secondDataSource() {
    return DataSourceBuilder.create().type(BasicDataSource.class).build();
}

firstDataSourceProperties has to be flagged as @Primary so that the database initializer feature uses your copy (if you use the initializer).

And your application.propoerties will look something like this:

app.datasource.first.url=jdbc:oracle:thin:@localhost/first
app.datasource.first.username=dbuser
app.datasource.first.password=dbpass
app.datasource.first.driver-class-name=oracle.jdbc.OracleDriver

app.datasource.second.url=jdbc:mariadb://localhost:3306/springboot_mariadb
app.datasource.second.username=dbuser
app.datasource.second.password=dbpass
app.datasource.second.driver-class-name=org.mariadb.jdbc.Driver

The above method is the correct to way to init multiple database in spring boot 2.0 migration and above. More read can be found here.

How to add header to a dataset in R?

You can also solve this problem by creating an array of values and assigning that array:

newheaders <- c("a", "b", "c", ... "x")
colnames(data) <- newheaders

Django Model() vs Model.objects.create()

The two syntaxes are not equivalent and it can lead to unexpected errors. Here is a simple example showing the differences. If you have a model:

from django.db import models

class Test(models.Model):

    added = models.DateTimeField(auto_now_add=True)

And you create a first object:

foo = Test.objects.create(pk=1)

Then you try to create an object with the same primary key:

foo_duplicate = Test.objects.create(pk=1)
# returns the error:
# django.db.utils.IntegrityError: (1062, "Duplicate entry '1' for key 'PRIMARY'")

foo_duplicate = Test(pk=1).save()
# returns the error:
# django.db.utils.IntegrityError: (1048, "Column 'added' cannot be null")

How can I get Apache gzip compression to work?

In my case i have used following code for enabling gzip compression in apache web server.

  # Compress HTML File, CSS File, JavaScript File, Text File, XML File and Fonts
    AddOutputFilterByType DEFLATE text/plain
    AddOutputFilterByType DEFLATE text/html
    AddOutputFilterByType DEFLATE text/xml
    AddOutputFilterByType DEFLATE application/json
    AddOutputFilterByType DEFLATE application/x-httpd-php
    AddOutputFilterByType DEFLATE text/css
    AddOutputFilterByType DEFLATE application/xml
    AddOutputFilterByType DEFLATE application/xhtml+xml
    AddOutputFilterByType DEFLATE application/rss+xml
    AddOutputFilterByType DEFLATE application/javascript
    AddOutputFilterByType DEFLATE application/x-javascript
    AddOutputFilterByType DEFLATE font/otf
    AddOutputFilterByType DEFLATE font/ttf

I have taken reference from http://www.tutsway.com/enable-gzip-compression-using-htacess.php.

Run a php app using tomcat?

tomcat is designed as JSP servlet container. Apache is designed PHP web server. Use apache as web server, responding for PHP request, and direct JSP servlet request to tomcat container. should be better implementation.

Force overwrite of local file with what's in origin repo?

Full sync has few tasks:

  • reverting changes
  • removing new files
  • get latest from remote repository

git reset HEAD --hard

git clean -f

git pull origin master

Or else, what I prefer is that, I may create a new branch with the latest from the remote using:

git checkout origin/master -b <new branch name>

origin is my remote repository reference, and master is my considered branch name. These may different from yours.

Laravel use same form for create and edit

For the creation add an empty object to the view.

return view('admin.profiles.create', ['profile' => new Profile()]);

Old function has a second parameter, default value, if you pass there the object's field, the input can be reused.

<input class="input" type="text" name="name" value="{{old('name', $profile->name)}}">

For the form action, you can use the correct endpoint.

<form action="{{ $profile->id == null ? '/admin/profiles' :  '/admin/profiles/' . $profile->id }} " method="POST">

And for the update you have to use PATCH method.

@isset($profile->id)
 {{ method_field('PATCH')}}
@endisset

Can't connect to docker from docker-compose

try this:

sudo ln -s /usr/local/bin/docker-compose /usr/bin/docker-compose

How to fix Error: "Could not find schema information for the attribute/element" by creating schema

Simple: In Visual Studio Report designer
1. Open the report in design mode and delete the dataset from the RDLC File
2. Open solution Explorer and delete the actual (corrupted) XSD file
3. Add the dataset back to the RDLC file.
4. The above procedure will create the new XSD file.
5. More detailed is below.

In Visual Studio, Open your RDLC file Report in Design mode. Click on the report and then Select View and then Report Data from the top line menu. Select Datasets and then Right Click and delete the dataset from the report. Next Open Solution Explorer, if it is not already open in your Visual Studio. Locate the XSD file (It should be the same name as the dataset you just deleted from the report). Now go back and right click again on the report data Datasets, and select Add Dataset . This will create a new XSD file and write the dataset properties to the report. Now your error message will be gone and any missing data will now appear in your reports.

Regular expression for only characters a-z, A-Z

Piggybacking on what the other answers say, since you don't know how to do them at all, here's an example of how you might do it in JavaScript:

var charactersOnly = "This contains only characters";
var nonCharacters = "This has _@#*($()*@#$(*@%^_(#@!$ non-characters";

if (charactersOnly.search(/[^a-zA-Z]+/) === -1) {
  alert("Only characters");
}

if (nonCharacters.search(/[^a-zA-Z]+/)) {
  alert("There are non characters.");
}

The / starting and ending the regular expression signify that it's a regular expression. The search function takes both strings and regexes, so the / are necessary to specify a regex.

From the MDN Docs, the function returns -1 if there is no match.

Also note: that this works for only a-z, A-Z. If there are spaces, it will fail.

Remove characters from C# string

Sounds like an ideal application for RegEx -- an engine designed for fast text manipulation. In this case:

Regex.Replace("He\"ll,o Wo'r.ld", "[@,\\.\";'\\\\]", string.Empty)

Can an abstract class have a constructor?

Consider this:

abstract class Product { 
    int value;
    public Product( int val ) {
        value= val;
    }
    abstract public int multiply();
}

class TimesTwo extends Product {
    public int mutiply() {
       return value * 2;
    }
}

The superclass is abstract and has a constructor.

How do I convert a file path to a URL in ASP.NET

This worked for me:

HttpContext.Current.Request.Url.GetLeftPart(UriPartial.Authority) + HttpRuntime.AppDomainAppVirtualPath + "ImageName";

Makefile: How to correctly include header file and its directory?

The preprocessor is looking for StdCUtil/split.h in

and in

  • $INC_DIR (i.e. ../StdCUtil/ = /root/Core/../StdCUtil/ = /root/StdCUtil/). So ../StdCUtil/ + StdCUtil/split.h = ../StdCUtil/StdCUtil/split.h and the file is missing

You can fix the error changing the $INC_DIR variable (best solution):

$INC_DIR = ../

or the include directive:

#include "split.h"

but in this way you lost the "path syntax" that makes it very clear what namespace or module the header file belongs to.

Reference:

EDIT/UPDATE

It should also be

CXX = g++
CXXFLAGS = -c -Wall -I$(INC_DIR)

...

%.o: %.cpp $(DEPS)
    $(CXX) -o $@ $< $(CXXFLAGS)

C++ Array Of Pointers

If you don't use the STL, then the code looks a lot bit like C.

#include <cstdlib>
#include <new>

template< class T >
void append_to_array( T *&arr, size_t &n, T const &obj ) {
    T *tmp = static_cast<T*>( std::realloc( arr, sizeof(T) * (n+1) ) );
    if ( tmp == NULL ) throw std::bad_alloc( __FUNCTION__ );
       // assign things now that there is no exception
    arr = tmp;
    new( &arr[ n ] ) T( obj ); // placement new
    ++ n;
}

T can be any POD type, including pointers.

Note that arr must be allocated by malloc, not new[].

.bashrc at ssh login

For an excellent resource on how bash invocation works, what dotfiles do what, and how you should use/configure them, read this:

Div with margin-left and width:100% overflowing on the right side

<div style="width:100%;">
    <div style="margin-left:45px;">
       <asp:TextBox ID="txtTitle" runat="server" Width="100%"></asp:TextBox><br />
    </div>
</div>

Frame Buster Buster ... buster code needed

If you look at the values returned by setInterval() they are usually single digits, so you can usually disable all such interrupts with a single line of code:

for (var j = 0 ; j < 256 ; ++j) clearInterval(j)

Replace line break characters with <br /> in ASP.NET MVC Razor view

Use the CSS white-space property instead of opening yourself up to XSS vulnerabilities!

<span style="white-space: pre-line">@Model.CommentText</span>

What is Vim recording and how can it be disabled?

As others have said, it's macro recording, and you turn it off with q. Here's a nice article about how-to and why it's useful.

How can I add a line to a file in a shell script?

sed is line based, so I'm not sure why you want to do this with sed. The paradigm is more processing one line at a time( you could also programatically find the # of fields in the CSV and generate your header line with awk) Why not just

echo "c1, c2, ... " >> file
cat testfile.csv >> file

?

Markdown and including multiple files

In fact you can use \input{filename} and \include{filename} which are latex commands, directly in Pandoc, because it supports nearly all html and latex syntax.

But beware, the included file will be treated as latex file. But you can compile your markdown to latex with Pandox easily.

What is a good practice to check if an environmental variable exists or not?

I'd recommend the following solution.

It prints the env vars you didn't include, which lets you add them all at once. If you go for the for loop, you're going to have to rerun the program to see each missing var.

from os import environ

REQUIRED_ENV_VARS = {"A", "B", "C", "D"}
diff = REQUIRED_ENV_VARS.difference(environ)
if len(diff) > 0:
    raise EnvironmentError(f'Failed because {diff} are not set')

maven "cannot find symbol" message unhelpful

In my case the problem was in a child jar which was not rebuilt since I have added a new class, pom.xml of that child jar was not related to my failed pom.xml as child-to-parent relation (using <parent> tag). So I rebuilt the child jar after which the error had gone.

How do I make a JSON object with multiple arrays?

A good book I'm reading: Professional JavaScript for Web Developers by Nicholas C. Zakas 3rd Edition has the following information regarding JSON Syntax:

"JSON Syntax allows the representation of three types of values".

Regarding the one you're interested in, Arrays it says:

"Arrays are represented in JSON using array literal notation from JavaScript. For example, this is an array in JavaScript:

var values = [25, "hi", true];

You can represent this same array in JSON using a similar syntax:

[25, "hi", true]

Note the absence of a variable or a semicolon. Arrays and objects can be used together to represent more complex collections of data, such as:

{
    "books":
              [
                {
                    "title": "Professional JavaScript",
                    "authors": [
                        "Nicholas C. Zakas"
                    ],
                    "edition": 3,
                    "year": 2011
                },
                {
                    "title": "Professional JavaScript",
                    "authors": [
                        "Nicholas C.Zakas"
                    ],
                    "edition": 2,
                    "year": 2009
                },
                {
                    "title": "Professional Ajax",
                    "authors": [
                        "Nicholas C. Zakas",
                        "Jeremy McPeak",
                        "Joe Fawcett"
                    ],
                    "edition": 2,
                    "year": 2008
                }
              ]
}

This Array contains a number of objects representing books, Each object has several keys, one of which is "authors", which is another array. Objects and arrays are typically top-level parts of a JSON data structure (even though this is not required) and can be used to create a large number of data structures."

To serialize (convert) a JavaScript object into a JSON string you can use the JSON object stringify() method. For the example from Mark Linus answer:

var cars = [{
    color: 'gray',
    model: '1',
    nOfDoors: 4
    },
    {
    color: 'yellow',
    model: '2',
    nOfDoors: 4
}];

cars is now a JavaScript object. To convert it into a JSON object you could do:

var jsonCars = JSON.stringify(cars);

Which yields:

"[{"color":"gray","model":"1","nOfDoors":4},{"color":"yellow","model":"2","nOfDoors":4}]"

To do the opposite, convert a JSON object into a JavaScript object (this is called parsing), you would use the parse() method. Search for those terms if you need more information... or get the book, it has many examples.

Importing the private-key/public-certificate pair in the Java KeyStore

A keystore needs a keystore file. The KeyStore class needs a FileInputStream. But if you supply null (instead of FileInputStream instance) an empty keystore will be loaded. Once you create a keystore, you can verify its integrity using keytool.

Following code creates an empty keystore with empty password

  KeyStore ks2 = KeyStore.getInstance("jks");
  ks2.load(null,"".toCharArray());
  FileOutputStream out = new FileOutputStream("C:\\mykeytore.keystore");
  ks2.store(out, "".toCharArray());

Once you have the keystore, importing certificate is very easy. Checkout this link for the sample code.

Hibernate show real SQL

Can I see (...) the real SQL

If you want to see the SQL sent directly to the database (that is formatted similar to your example), you'll have to use some kind of jdbc driver proxy like P6Spy (or log4jdbc).

Alternatively you can enable logging of the following categories (using a log4j.properties file here):

log4j.logger.org.hibernate.SQL=DEBUG
log4j.logger.org.hibernate.type=TRACE

The first is equivalent to hibernate.show_sql=true, the second prints the bound parameters among other things.

Reference

With arrays, why is it the case that a[5] == 5[a]?

To answer the question literally. It is not always true that x == x

double zero = 0.0;
double a[] = { 0,0,0,0,0, zero/zero}; // NaN
cout << (a[5] == 5[a] ? "true" : "false") << endl;

prints

false

Determining the size of an Android view at runtime

Use the ViewTreeObserver on the View to wait for the first layout. Only after the first layout will getWidth()/getHeight()/getMeasuredWidth()/getMeasuredHeight() work.

ViewTreeObserver viewTreeObserver = view.getViewTreeObserver();
if (viewTreeObserver.isAlive()) {
  viewTreeObserver.addOnGlobalLayoutListener(new OnGlobalLayoutListener() {
    @Override
    public void onGlobalLayout() {
      view.getViewTreeObserver().removeOnGlobalLayoutListener(this);
      viewWidth = view.getWidth();
      viewHeight = view.getHeight();
    }
  });
}

Clear listview content?

It's simple .First you should clear your collection and after clear list like this code :

 yourCollection.clear();
 setListAdapter(null);

When should I use "this" in a class?

To make sure that the current object's members are used. Cases where thread safety is a concern, some applications may change the wrong objects member values, for that reason this should be applied to the member so that the correct object member value is used.

If your object is not concerned with thread safety then there is no reason to specify which object member's value is used.

ssh: check if a tunnel is alive

Autossh is best option - checking process is not working in all cases (e.g. zombie process, network related problems)

example:

autossh -M 2323 -c arcfour -f -N -L 8088:localhost:80 host2

Why doesn't list have safe "get" method like dictionary?

This works if you want the first element, like my_list.get(0)

>>> my_list = [1,2,3]
>>> next(iter(my_list), 'fail')
1
>>> my_list = []
>>> next(iter(my_list), 'fail')
'fail'

I know it's not exactly what you asked for but it might help others.

How to set Toolbar text and back arrow color

<android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimaryDark"
            app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />
</android.support.design.widget.AppBarLayout>

How to get root view controller?

Swift 3

let rootViewController = UIApplication.shared.keyWindow?.rootViewController

How to get the browser viewport dimensions?

This code is from http://andylangton.co.uk/articles/javascript/get-viewport-size-javascript/

function viewport() {
    var e = window, a = 'inner';
    if (!('innerWidth' in window )) {
        a = 'client';
        e = document.documentElement || document.body;
    }
    return { width : e[ a+'Width' ] , height : e[ a+'Height' ] };
}

NB : to read the width, use console.log('viewport width'+viewport().width);

Error : ORA-01704: string literal too long

To solve this issue on my side, I had to use a combo of what was already proposed there

DECLARE
  chunk1 CLOB; chunk2 CLOB; chunk3 CLOB;
BEGIN
  chunk1 := 'very long literal part 1';
  chunk2 := 'very long literal part 2';
  chunk3 := 'very long literal part 3';

  INSERT INTO table (MY_CLOB)
  SELECT ( chunk1 || chunk2 || chunk3 ) FROM dual;
END;

Hope this helps.

HTML5 live streaming

It is not possible to use the RTMP protocol in HTML 5, because the RTMP protocol is only used between the server and the flash player. So you can use the other streaming protocols for viewing the streaming videos in HTML 5.

Convert DataTable to List<T>

you can convert your datatable to list. check the following link

https://stackoverflow.com/a/35171050/1805776

public static class Helper
{
    public static List<T> DataTableToList<T>(this DataTable dataTable) where T : new()
    {
        var dataList = new List<T>();

        //Define what attributes to be read from the class
        const System.Reflection.BindingFlags flags = System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance;

        //Read Attribute Names and Types
        var objFieldNames = typeof(T).GetProperties(flags).Cast<System.Reflection.PropertyInfo>().
            Select(item => new
            {
                Name = item.Name,
                Type = Nullable.GetUnderlyingType(item.PropertyType) ?? item.PropertyType
            }).ToList();

        //Read Datatable column names and types
        var dtlFieldNames = dataTable.Columns.Cast<DataColumn>().
            Select(item => new
            {
                Name = item.ColumnName,
                Type = item.DataType
            }).ToList();

        foreach (DataRow dataRow in dataTable.AsEnumerable().ToList())
        {
            var classObj = new T();

            foreach (var dtField in dtlFieldNames)
            {
                System.Reflection.PropertyInfo propertyInfos = classObj.GetType().GetProperty(dtField.Name);

                var field = objFieldNames.Find(x => x.Name == dtField.Name);

                if (field != null)
                {

                    if (propertyInfos.PropertyType == typeof(DateTime))
                    {
                        propertyInfos.SetValue
                        (classObj, convertToDateTime(dataRow[dtField.Name]), null);
                    }
                    else if (propertyInfos.PropertyType == typeof(Nullable<DateTime>))
                    {
                        propertyInfos.SetValue
                        (classObj, convertToDateTime(dataRow[dtField.Name]), null);
                    }
                    else if (propertyInfos.PropertyType == typeof(int))
                    {
                        propertyInfos.SetValue
                        (classObj, ConvertToInt(dataRow[dtField.Name]), null);
                    }
                    else if (propertyInfos.PropertyType == typeof(long))
                    {
                        propertyInfos.SetValue
                        (classObj, ConvertToLong(dataRow[dtField.Name]), null);
                    }
                    else if (propertyInfos.PropertyType == typeof(decimal))
                    {
                        propertyInfos.SetValue
                        (classObj, ConvertToDecimal(dataRow[dtField.Name]), null);
                    }
                    else if (propertyInfos.PropertyType == typeof(String))
                    {
                        if (dataRow[dtField.Name].GetType() == typeof(DateTime))
                        {
                            propertyInfos.SetValue
                            (classObj, ConvertToDateString(dataRow[dtField.Name]), null);
                        }
                        else
                        {
                            propertyInfos.SetValue
                            (classObj, ConvertToString(dataRow[dtField.Name]), null);
                        }
                    }
                    else
                    {

                        propertyInfos.SetValue
                            (classObj, Convert.ChangeType(dataRow[dtField.Name], propertyInfos.PropertyType), null);

                    }
                }
            }
            dataList.Add(classObj);
        }
        return dataList;
    }

    private static string ConvertToDateString(object date)
    {
        if (date == null)
            return string.Empty;

        return date == null ? string.Empty : Convert.ToDateTime(date).ConvertDate();
    }

    private static string ConvertToString(object value)
    {
        return Convert.ToString(ReturnEmptyIfNull(value));
    }

    private static int ConvertToInt(object value)
    {
        return Convert.ToInt32(ReturnZeroIfNull(value));
    }

    private static long ConvertToLong(object value)
    {
        return Convert.ToInt64(ReturnZeroIfNull(value));
    }

    private static decimal ConvertToDecimal(object value)
    {
        return Convert.ToDecimal(ReturnZeroIfNull(value));
    }

    private static DateTime convertToDateTime(object date)
    {
        return Convert.ToDateTime(ReturnDateTimeMinIfNull(date));
    }

    public static string ConvertDate(this DateTime datetTime, bool excludeHoursAndMinutes = false)
    {
        if (datetTime != DateTime.MinValue)
        {
            if (excludeHoursAndMinutes)
                return datetTime.ToString("yyyy-MM-dd");
            return datetTime.ToString("yyyy-MM-dd HH:mm:ss.fff");
        }
        return null;
    }
    public static object ReturnEmptyIfNull(this object value)
    {
        if (value == DBNull.Value)
            return string.Empty;
        if (value == null)
            return string.Empty;
        return value;
    }
    public static object ReturnZeroIfNull(this object value)
    {
        if (value == DBNull.Value)
            return 0;
        if (value == null)
            return 0;
        return value;
    }
    public static object ReturnDateTimeMinIfNull(this object value)
    {
        if (value == DBNull.Value)
            return DateTime.MinValue;
        if (value == null)
            return DateTime.MinValue;
        return value;
    }
}

Visual Studio debugger error: Unable to start program Specified file cannot be found

I think that what you have to check is:

  1. if the target EXE is correctly configured in the project settings ("command", in the debugging tab). Since all individual projects run when you start debugging it's well possible that only the debugging target for the "ALL" solution is missing, check which project is currently active (you can also select the debugger target by changing the active project).

  2. dependencies (DLLs) are also located at the target debugee directory or can be loaded (you can use the "depends.exe" tool for checking dependencies of an executable or DLL).

How to get value at a specific index of array In JavaScript?

Array indexes in JavaScript start at zero for the first item, so try this:

var firstArrayItem = myValues[0]

Of course, if you actually want the second item in the array at index 1, then it's myValues[1].

See Accessing array elements for more info.

Stack Memory vs Heap Memory

Stack memory is specifically the range of memory that is accessible via the Stack register of the CPU. The Stack was used as a way to implement the "Jump-Subroutine"-"Return" code pattern in assembly language, and also as a means to implement hardware-level interrupt handling. For instance, during an interrupt, the Stack was used to store various CPU registers, including Status (which indicates the results of an operation) and Program Counter (where was the CPU in the program when the interrupt occurred).

Stack memory is very much the consequence of usual CPU design. The speed of its allocation/deallocation is fast because it is strictly a last-in/first-out design. It is a simple matter of a move operation and a decrement/increment operation on the Stack register.

Heap memory was simply the memory that was left over after the program was loaded and the Stack memory was allocated. It may (or may not) include global variable space (it's a matter of convention).

Modern pre-emptive multitasking OS's with virtual memory and memory-mapped devices make the actual situation more complicated, but that's Stack vs Heap in a nutshell.

How to set a Fragment tag by code?

This is the best way I have found :

   public class MainActivity extends AppCompatActivity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (savedInstanceState == null) {
          // Let's first dynamically add a fragment into a frame container
          getSupportFragmentManager().beginTransaction(). 
              replace(R.id.flContainer, new DemoFragment(), "SOMETAG").
              commit();
          // Now later we can lookup the fragment by tag
          DemoFragment fragmentDemo = (DemoFragment) 
              getSupportFragmentManager().findFragmentByTag("SOMETAG");
        }
    }
}

What is Node.js' Connect, Express and "middleware"?

Node.js itself offers an HTTP module, whose createServer method returns an object that you can use to respond to HTTP requests. That object inherits the http.Server prototype.

How to increase the clickable area of a <a> tag button?

Just make the anchor display: block and width/height: 100%. Eg:

.button a {
    display: block;
    width: 100%;
    height: 100%;
}

jsFiddle: http://jsfiddle.net/4mHTa/

How do I hide an element on a click event anywhere outside of the element?

  $(document).on('click', function(e) { // Hides the div by clicking any where in the screen
        if ( $(e.target).closest('#suggest_input').length ) {
            $(".suggest_div").show();
        }else if ( ! $(e.target).closest('.suggest_container').length ) {
            $('.suggest_div').hide();
        }
    });

Here #suggest_input in is the name of textbox and .suggest_container is the ul class name and .suggest_div is the main div element for my auto-suggest.

this code is for hiding the div elements by clicking any where in the screen. Before doing every thing please understand the code and copy it...

JPA EntityManager: Why use persist() over merge()?

You may have come here for advice on when to use persist and when to use merge. I think that it depends the situation: how likely is it that you need to create a new record and how hard is it to retrieve persisted data.

Let's presume you can use a natural key/identifier.

  • Data needs to be persisted, but once in a while a record exists and an update is called for. In this case you could try a persist and if it throws an EntityExistsException, you look it up and combine the data:

    try { entityManager.persist(entity) }

    catch(EntityExistsException exception) { /* retrieve and merge */ }

  • Persisted data needs to be updated, but once in a while there is no record for the data yet. In this case you look it up, and do a persist if the entity is missing:

    entity = entityManager.find(key);

    if (entity == null) { entityManager.persist(entity); }

    else { /* merge */ }

If you don't have natural key/identifier, you'll have a harder time to figure out whether the entity exist or not, or how to look it up.

The merges can be dealt with in two ways, too:

  1. If the changes are usually small, apply them to the managed entity.
  2. If changes are common, copy the ID from the persisted entity, as well as unaltered data. Then call EntityManager::merge() to replace the old content.

How do I make a newline after a twitter bootstrap element?

You're using span6 and span2. Both of these classes are "float:left" meaning, if possible they will always try to sit next to each other. Twitter bootstrap is based on a 12 grid system. So you should generally always get the span**#** to add up to 12.

E.g.: span4 + span4 + span4 OR span6 + span6 OR span4 + span3 + span5.

To force a span down though, without listening to the previous float you can use twitter bootstraps clearfix class. To do this, your code should look like this:

<ul class="nav nav-tabs span2">
  <li><a href="./index.html"><i class="icon-black icon-music"></i></a></li>
  <li><a href="./about.html"><i class="icon-black icon-eye-open"></i></a></li>
  <li><a href="./team.html"><i class="icon-black icon-user"></i></a></li>
  <li><a href="./contact.html"><i class="icon-black icon-envelope"></i></a></li>
</ul>
<!-- Notice this following line -->
<div class="clearfix"></div>
<div class="well span6">
  <h3>I wish this appeared on the next line without having to gratuitously use BR!</h3>
</div>

Python circular importing?

To understand circular dependencies, you need to remember that Python is essentially a scripting language. Execution of statements outside methods occurs at compile time. Import statements are executed just like method calls, and to understand them you should think about them like method calls.

When you do an import, what happens depends on whether the file you are importing already exists in the module table. If it does, Python uses whatever is currently in the symbol table. If not, Python begins reading the module file, compiling/executing/importing whatever it finds there. Symbols referenced at compile time are found or not, depending on whether they have been seen, or are yet to be seen by the compiler.

Imagine you have two source files:

File X.py

def X1:
    return "x1"

from Y import Y2

def X2:
    return "x2"

File Y.py

def Y1:
    return "y1"

from X import X1

def Y2:
    return "y2"

Now suppose you compile file X.py. The compiler begins by defining the method X1, and then hits the import statement in X.py. This causes the compiler to pause compilation of X.py and begin compiling Y.py. Shortly thereafter the compiler hits the import statement in Y.py. Since X.py is already in the module table, Python uses the existing incomplete X.py symbol table to satisfy any references requested. Any symbols appearing before the import statement in X.py are now in the symbol table, but any symbols after are not. Since X1 now appears before the import statement, it is successfully imported. Python then resumes compiling Y.py. In doing so it defines Y2 and finishes compiling Y.py. It then resumes compilation of X.py, and finds Y2 in the Y.py symbol table. Compilation eventually completes w/o error.

Something very different happens if you attempt to compile Y.py from the command line. While compiling Y.py, the compiler hits the import statement before it defines Y2. Then it starts compiling X.py. Soon it hits the import statement in X.py that requires Y2. But Y2 is undefined, so the compile fails.

Please note that if you modify X.py to import Y1, the compile will always succeed, no matter which file you compile. However if you modify file Y.py to import symbol X2, neither file will compile.

Any time when module X, or any module imported by X might import the current module, do NOT use:

from X import Y

Any time you think there may be a circular import you should also avoid compile time references to variables in other modules. Consider the innocent looking code:

import X
z = X.Y

Suppose module X imports this module before this module imports X. Further suppose Y is defined in X after the import statement. Then Y will not be defined when this module is imported, and you will get a compile error. If this module imports Y first, you can get away with it. But when one of your co-workers innocently changes the order of definitions in a third module, the code will break.

In some cases you can resolve circular dependencies by moving an import statement down below symbol definitions needed by other modules. In the examples above, definitions before the import statement never fail. Definitions after the import statement sometimes fail, depending on the order of compilation. You can even put import statements at the end of a file, so long as none of the imported symbols are needed at compile time.

Note that moving import statements down in a module obscures what you are doing. Compensate for this with a comment at the top of your module something like the following:

#import X   (actual import moved down to avoid circular dependency)

In general this is a bad practice, but sometimes it is difficult to avoid.

Python - Extracting and Saving Video Frames

This is Function which will convert most of the video formats to number of frames there are in the video. It works on Python3 with OpenCV 3+

import cv2
import time
import os

def video_to_frames(input_loc, output_loc):
    """Function to extract frames from input video file
    and save them as separate frames in an output directory.
    Args:
        input_loc: Input video file.
        output_loc: Output directory to save the frames.
    Returns:
        None
    """
    try:
        os.mkdir(output_loc)
    except OSError:
        pass
    # Log the time
    time_start = time.time()
    # Start capturing the feed
    cap = cv2.VideoCapture(input_loc)
    # Find the number of frames
    video_length = int(cap.get(cv2.CAP_PROP_FRAME_COUNT)) - 1
    print ("Number of frames: ", video_length)
    count = 0
    print ("Converting video..\n")
    # Start converting the video
    while cap.isOpened():
        # Extract the frame
        ret, frame = cap.read()
        # Write the results back to output location.
        cv2.imwrite(output_loc + "/%#05d.jpg" % (count+1), frame)
        count = count + 1
        # If there are no more frames left
        if (count > (video_length-1)):
            # Log the time again
            time_end = time.time()
            # Release the feed
            cap.release()
            # Print stats
            print ("Done extracting frames.\n%d frames extracted" % count)
            print ("It took %d seconds forconversion." % (time_end-time_start))
            break

if __name__=="__main__":

    input_loc = '/path/to/video/00009.MTS'
    output_loc = '/path/to/output/frames/'
    video_to_frames(input_loc, output_loc)

It supports .mts and normal files like .mp4 and .avi. Tried and Tested on .mts files. Works like a Charm.

How do I validate a date in rails?

If you want Rails 3 or Ruby 1.9 compatibility try the date_validator gem.

HTML: Image won't display?

_x000D_
_x000D_
img {_x000D_
  width: 200px;_x000D_
}
_x000D_
<img src="https://image.ibb.co/gmmneK/children_593313_340.jpg"/>_x000D_
_x000D_
<img src="https://image.ibb.co/e0RLzK/entrepreneur_1340649_340.jpg"/>_x000D_
_x000D_
<img src="https://image.ibb.co/cks4Rz/typing_849806_340.jpg"/>
_x000D_
_x000D_
_x000D_

please see the above code.

How to use onSavedInstanceState example please

Basically onSaveInstanceState(Bundle outBundle) will give you a bundle. When you look at the Bundle class, you will see that you can put lots of different stuff inside it. At the next call of onCreate(), you just get that Bundle back as an argument. Then you can read your values again and restore your activity.

Lets say you have an activity with an EditText. The user wrote some text inside it. After that the system calls your onSaveInstanceState(). You read the text from the EditText and write it into the Bundle via Bundle.putString("edit_text_value", theValue).

Now onCreate is called. You check if the supplied bundle is not null. If thats the case, you can restore your value via Bundle.getString("edit_text_value") and put it back into your EditText.

How to change onClick handler dynamically?

Use .onclick (all lowercase). Like so:

document.getElementById("foo").onclick = function () {
  alert('foo'); // do your stuff
  return false; // <-- to suppress the default link behaviour
};

Actually, you'll probably find yourself way better off using some good library (I recommend jQuery for several reasons) to get you up and running, and writing clean javascript.

Cross-browser (in)compatibilities are a right hell to deal with for anyone - let alone someone who's just starting.

Use getElementById on HTMLElement instead of HTMLDocument

Thanks to dee for the answer above with the Scrape() subroutine. The code worked perfectly as written, and I was able to then convert the code to work with the specific website I am trying to scrape.

I do not have enough reputation to upvote or to comment, but I do actually have some minor improvements to add to dee's answer:

  1. You will need to add the VBA Reference via "Tools\References" to "Microsoft HTML Object Library in order for the code to compile.

  2. I commented out the Browser.Visible line and added the comment as follows

    'if you need to debug the browser page, uncomment this line:
    'Browser.Visible = True
    
  3. And I added a line to close the browser before Set Browser = Nothing:

    Browser.Quit
    

Thanks again dee!

ETA: this works on machines with IE9, but not machines with IE8. Anyone have a fix?

Found the fix myself, so came back here to post it. The ClassName function is available in IE9. For this to work in IE8, you use querySelectorAll, with a dot preceding the class name of the object you are looking for:

'Set repList = doc.getElementsByClassName("reportList") 'only works in IE9, not in IE8
Set repList = doc.querySelectorAll(".reportList")       'this works in IE8+

Keyboard shortcut to change font size in Eclipse?

Oddly, working on a .js file and Ctrl, Shift, += works to zoom in (and Ctrl - works to zoom out but you have to select 1 or 2 after Ctrl -). This only works when I'm in the js file but the zoom applies to all my open tabs. Using Eclipse Juno on Ubuntu.

How to make Bootstrap carousel slider use mobile left/right swipe

I needed to add this functionality to a project I was working on recently and adding jQuery Mobile just to solve this problem seemed like overkill, so I came up with a solution and put it on github: bcSwipe (Bootstrap Carousel Swipe).

It's a lightweight jQuery plugin (~600 bytes minified vs jQuery Mobile touch events at 8kb), and it's been tested on Android and iOS.

This is how you use it:

$('.carousel').bcSwipe({ threshold: 50 });

virtualbox Raw-mode is unavailable courtesy of Hyper-V windows 10

To check the status of Hyper-v in Windows 10,

right click <"start"> ? Run ? OptionalFeatures.exe, ? look for the "Hyper-V" option.

The box should be empty, not checked or shaded.

Make sure to fully power down and reboot the host after changing the Hyper-v setting.

PS

Docker known for activating this "Hyper-V" without asking for user opinion and then Oracle VirtualBox does not want to work.

Disabling the button after once click

Use modern Js events, with "once"!

const button = document.getElementById(btnId);
button.addEventListener("click", function() {
    // Submit form
}, {once : true});

// Disabling works too, but this is a more standard approach for general one-time events

Documentation, CanIUse

How to create a new column in a select query

select A, B, 'c' as C
from MyTable

How can I regenerate ios folder in React Native project?

I just found myself with this problem too, but I just solved it.

Surely when running the "react-native upgrade" command, it gave them the message that it was not necessary to update or with the command "react-native eject" that the command is not recognized.

react-native upgrade

Now you should use the react-native upgrade --legacy true command to back up your android folders or ios as the case may be as this command will replace your files.

react-native upgrade --legacy true

Now it's just telling you not to replace your package.json

Sending SOAP request using Python Requests

It is indeed possible.

Here is an example calling the Weather SOAP Service using plain requests lib:

import requests
url="http://wsf.cdyne.com/WeatherWS/Weather.asmx?WSDL"
#headers = {'content-type': 'application/soap+xml'}
headers = {'content-type': 'text/xml'}
body = """<?xml version="1.0" encoding="UTF-8"?>
         <SOAP-ENV:Envelope xmlns:ns0="http://ws.cdyne.com/WeatherWS/" xmlns:ns1="http://schemas.xmlsoap.org/soap/envelope/" 
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
            <SOAP-ENV:Header/>
              <ns1:Body><ns0:GetWeatherInformation/></ns1:Body>
         </SOAP-ENV:Envelope>"""

response = requests.post(url,data=body,headers=headers)
print response.content

Some notes:

  • The headers are important. Most SOAP requests will not work without the correct headers. application/soap+xml is probably the more correct header to use (but the weatherservice prefers text/xml
  • This will return the response as a string of xml - you would then need to parse that xml.
  • For simplicity I have included the request as plain text. But best practise would be to store this as a template, then you can load it using jinja2 (for example) - and also pass in variables.

For example:

from jinja2 import Environment, PackageLoader
env = Environment(loader=PackageLoader('myapp', 'templates'))
template = env.get_template('soaprequests/WeatherSericeRequest.xml')
body = template.render()

Some people have mentioned the suds library. Suds is probably the more correct way to be interacting with SOAP, but I often find that it panics a little when you have WDSLs that are badly formed (which, TBH, is more likely than not when you're dealing with an institution that still uses SOAP ;) ).

You can do the above with suds like so:

from suds.client import Client
url="http://wsf.cdyne.com/WeatherWS/Weather.asmx?WSDL"
client = Client(url)
print client ## shows the details of this service

result = client.service.GetWeatherInformation() 
print result 

Note: when using suds, you will almost always end up needing to use the doctor!

Finally, a little bonus for debugging SOAP; TCPdump is your friend. On Mac, you can run TCPdump like so:

sudo tcpdump -As 0 

This can be helpful for inspecting the requests that actually go over the wire.

The above two code snippets are also available as gists:

How can I capture packets in Android?

It's probably worth mentioning that for http/https some people proxy their browser traffic through Burp/ZAP or another intercepting "attack proxy". A thread that covers options for this on Android devices can be found here: https://android.stackexchange.com/questions/32366/which-browser-does-support-proxies

Getting user input

Use the raw_input() function to get input from users (2.x):

print "Enter a file name:",
filename = raw_input()

or just:

filename = raw_input('Enter a file name: ')

or if in Python 3.x:

filename = input('Enter a file name: ')

Is it possible to send an array with the Postman Chrome extension?

You need to suffix your variable name with [] like this:

send_array_param_with_postman

If that doesn't work, try not putting indexes in brackets:

my_array[]  value1
my_array[]  value2

Note:

  • If you are using the postman packaged app, you can send an array by selecting raw / json (instead of form-data). Also, make sure to set Content-Type as application/json in Headers tab. Here is example for raw data {"user_ids": ["123" "233"]}, don't forget the quotes!

  • If you are using the postman REST client you have to use the method I described above because passing data as raw (json) won't work. There is a bug in the postman REST client (At least I get the bug when I use 0.8.4.6).

HTML tag <a> want to add both href and onclick working

Use jQuery. You need to capture the click event and then go on to the website.

_x000D_
_x000D_
$("#myHref").on('click', function() {_x000D_
  alert("inside onclick");_x000D_
  window.location = "http://www.google.com";_x000D_
});
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<a href="#" id="myHref">Click me</a>
_x000D_
_x000D_
_x000D_

How to set an button align-right with Bootstrap?

This work for me in bootstrap 4:

    <div class="alert alert-info">
      <a href="#" class="alert-link">Summary:Its some description.......testtesttest</a>  
      <button type="button" class="btn btn-primary btn-lg float-right">Large button</button>
    </div>

Imported a csv-dataset to R but the values becomes factors

By default, read.csv checks the first few rows of your data to see whether to treat each variable as numeric. If it finds non-numeric values, it assumes the variable is character data, and character variables are converted to factors.

It looks like the PTS and MP variables in your dataset contain non-numerics, which is why you're getting unexpected results. You can force these variables to numeric with

point <- as.numeric(as.character(point))
time <- as.numeric(as.character(time))

But any values that can't be converted will become missing. (The R FAQ gives a slightly different method for factor -> numeric conversion but I can never remember what it is.)

Django - makemigrations - No changes detected

I had another problem not described here, which drove me nuts.

class MyModel(models.Model):
    name = models.CharField(max_length=64, null=True)  # works
    language_code = models.CharField(max_length=2, default='en')  # works
    is_dumb = models.BooleanField(default=False),  # doesn't work

I had a trailing ',' in one line perhaps from copy&paste. The line with is_dumb doesn't created a model migration with './manage.py makemigrations' but also didn't throw an error. After removing the ',' it worked as expected.

So be careful when you do copy&paste :-)

CSS how to make an element fade in and then fade out?

A way to do this would be to set the color of the element to black, and then fade to the color of the background like this:

<style> 
p {
animation-name: example;
animation-duration: 2s;
}

@keyframes example {
from {color:black;}
to {color:white;}
}
</style>
<p>I am FADING!</p>

I hope this is what you needed!

Why, Fatal error: Class 'PHPUnit_Framework_TestCase' not found in ...?

For those arriving here after updating phpunit to version 6 or greater released on 2017-02-03 (e.g. with composer), you may be getting this error because phpunit code is now namespaced (check changelog).

You will need to refactor things like \PHPUnit_Framework_TestCase to \PHPUnit\Framework\TestCase

Converting cv::Mat to IplImage*

Mat image1;
IplImage* image2=cvCloneImage(&(IplImage)image1);

Guess this will do the job.

Edit: If you face compilation errors, try this way:

cv::Mat image1;
IplImage* image2;
image2 = cvCreateImage(cvSize(image1.cols,image1.rows),8,3);
IplImage ipltemp=image1;
cvCopy(&ipltemp,image2);

XSLT counting elements with a given value

<xsl:variable name="count" select="count(/Property/long = $parPropId)"/>

Un-tested but I think that should work. I'm assuming the Property nodes are direct children of the root node and therefor taking out your descendant selector for peformance

Remove columns from dataframe where ALL values are NA

Another options with purrr package:

library(dplyr)

df <- data.frame(a = NA,
                 b = seq(1:5), 
                 c = c(rep(1, 4), NA))

df %>% purrr::discard(~all(is.na(.)))
df %>% purrr::keep(~!all(is.na(.)))

How can I make a horizontal ListView in Android?

Gallery is the best solution, i have tried it. I was working on one mail app, in which mails in the inbox where displayed as listview, i wanted an horizontal view, i just converted listview to gallery and everything worked fine as i needed without any errors. For the scroll effect i enabled gesture listener for the gallery. I hope this answer may help u.

Lodash remove duplicates from array

You could use lodash method _.uniqWith, it is available in the current version of lodash 4.17.2.

Example:

var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }, { 'x': 1, 'y': 2 }];

_.uniqWith(objects, _.isEqual);
// => [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }]

More info: https://lodash.com/docs/#uniqWith

favicon.png vs favicon.ico - why should I use PNG instead of ICO?

The theoretical advantage of *.ico files is that they are containers than can hold more than one icon. You could for instance store an image with alpha channel and a 16 colour version for legacy systems, or you could add 32x32 and 48x48 icons (which would show up when e.g. dragging a link to Windows explorer).

This good idea, however, tends to clash with browser implementations.

Execute Stored Procedure from a Function

Functions are not allowed to have side-effects such as altering table contents.

Stored Procedures are.

If a function called a stored procedure, the function would become able to have side-effects.


So, sorry, but no, you can't call a stored procedure from a function.

How can two strings be concatenated?

As others have pointed out, paste() is the way to go. But it can get annoying to have to type paste(str1, str2, str3, sep='') everytime you want the non-default separator.

You can very easily create wrapper functions that make life much simpler. For instance, if you find yourself concatenating strings with no separator really often, you can do:

p <- function(..., sep='') {
    paste(..., sep=sep, collapse=sep)
}

or if you often want to join strings from a vector (like implode() from PHP):

implode <- function(..., sep='') {
     paste(..., collapse=sep)
}

Allows you do do this:

p('a', 'b', 'c')
#[1] "abc"
vec <- c('a', 'b', 'c')
implode(vec)
#[1] "abc"
implode(vec, sep=', ')
#[1] "a, b, c"

Also, there is the built-in paste0, which does the same thing as my implode, but without allowing custom separators. It's slightly more efficient than paste().

A select query selecting a select statement

I was over-complicating myself. After taking a long break and coming back, the desired output could be accomplished by this simple query:

SELECT Sandwiches.[Sandwich Type], Sandwich.Bread, Count(Sandwiches.[SandwichID]) AS [Total Sandwiches]
FROM Sandwiches
GROUP BY Sandwiches.[Sandwiches Type], Sandwiches.Bread;

Thanks for answering, it helped my train of thought.

How can I pass request headers with jQuery's getJSON() method?

The $.getJSON() method is shorthand that does not let you specify advanced options like that. To do that, you need to use the full $.ajax() method.

Notice in the documentation at http://api.jquery.com/jQuery.getJSON/:

This is a shorthand Ajax function, which is equivalent to:

$.ajax({
  url: url,
  dataType: 'json',
  data: data,
  success: callback
});

So just use $.ajax() and provide all the extra parameters you need.

How to change package name of an Android Application

  1. In your Android studio , at project panel , there is gear icon "Click on it".
  2. Uncheck the Compact Empty Middle Packages
  3. Now the package directory has been broken up i.e individual directories.
  4. Select the directory you want to rename.
  5. Right click on that particular directory.
  6. Select refactor and then rename option.
  7. The dialog box has been open up,rename it.
  8. After putting new name, click on Refactor.
  9. Then click on Do Refactor at bottom.
  10. Then android studio will update all changes.
  11. Now open build.gradle file and update the applicationId & sync it.
  12. Now go to manifest file and rename the package.
  13. Rebuild your Project.
  14. You are done :)

C# Threading - How to start and stop a thread

Use a static AutoResetEvent in your spawned threads to call back to the main thread using the Set() method. This guy has a fairly good demo in SO on how to use it.

AutoResetEvent clarification

For vs. while in C programming?

If you want a loop to execute while a condition is true, and not for a certain number of iterations, it is much easier for someone else to understand:

while (cond_true)

than something like this:

for (; cond_true ; )

Has been blocked by CORS policy: Response to preflight request doesn’t pass access control check

The provided solution here is correct. However, the same error can also occur from a user error, where your endpoint request method is NOT matching the method your using when making the request.

For example, the server endpoint is defined with "RequestMethod.PUT" while you are requesting the method as POST.

Bundler: Command not found

I'm running ubuntu 11.10 and bundle executable was located in:

/var/lib/gems/1.8/bin

Angular JS: Full example of GET/POST/DELETE/PUT client for a REST/CRUD backend?

Because your update uses PUT method, {entryId: $scope.entryId} is considered as data, to tell angular generate from the PUT data, you need to add params: {entryId: '@entryId'} when you define your update, which means

return $resource('http://localhost\\:3000/realmen/:entryId', {}, {
  query: {method:'GET', params:{entryId:''}, isArray:true},
  post: {method:'POST'},
  update: {method:'PUT', params: {entryId: '@entryId'}},
  remove: {method:'DELETE'}
});

Fix: Was missing a closing curly brace on the update line.

How to find the remainder of a division in C?

Use the modulus operator %, it returns the remainder.

int a = 5;
int b = 3;

if (a % b != 0) {
   printf("The remainder is: %i", a%b);
}

vim line numbers - how to have them on by default?

Terminal > su > password > vim /etc/vimrc

Click here and edit as in line number (13):

set nu

click here and Edit as "Line number (13)"

Storing image in database directly or as base64 data?

I recommend looking at modern databases like NoSQL and also I agree with user1252434's post. For instance I am storing a few < 500kb PNGs as base64 on my Mongo db with binary set to true with no performance hit at all. Mongo can be used to store large files like 10MB videos and that can offer huge time saving advantages in metadata searches for those videos, see storing large objects and files in mongodb.

Where can I find the default timeout settings for all browsers?

I managed to find network.http.connect.timeout for much older versions of Mozilla:

This preference was one of several added to allow low-level tweaking of the HTTP networking code. After a portion of the same code was significantly rewritten in 2001, the preference ceased to have any effect (as noted in all.js as early as September 2001).

Currently, the timeout is determined by the system-level connection establishment timeout. Adding a way to configure this value is considered low-priority.

It would seem that network.http.connect.timeout hasn't done anything for some time.

I also saw references to network.http.request.timeout, so I did a Google search. The results include lots of links to people recommending that others include it in about:config in what appears to be a mistaken belief that it actually does something, since the same search turns up this about:config entries article:

Pref removed (unused). Previously: HTTP-specific network timeout. Default value is 120.

The same page includes additional information about network.http.connect.timeout:

Pref removed (unused). Previously: determines how long to wait for a response until registering a timeout. Default value is 30.

Disclaimer: The information on the MozillaZine Knowledge Base may be incorrect, incomplete or out-of-date.

jQuery CSS Opacity

Try this:

jQuery('#main').css('opacity', '0.6');

or

jQuery('#main').css({'filter':'alpha(opacity=60)', 'zoom':'1', 'opacity':'0.6'});

if you want to support IE7, IE8 and so on.

How do I navigate to a parent route from a child route?

To navigate to the parent component regardless of the number of parameters in the current route or the parent route: Angular 6 update 1/21/19

   let routerLink = this._aRoute.parent.snapshot.pathFromRoot
        .map((s) => s.url)
        .reduce((a, e) => {
            //Do NOT add last path!
            if (a.length + e.length !== this._aRoute.parent.snapshot.pathFromRoot.length) {
                return a.concat(e);
            }
            return a;
        })
        .map((s) => s.path);
    this._router.navigate(routerLink);

This has the added bonus of being an absolute route you can use with the singleton Router.

(Angular 4+ for sure, probably Angular 2 too.)

Convert HTML5 into standalone Android App

You can use https://appery.io/ It is the same phonegap but in very convinient wrapper

How to get the name of the current method from code

Does this not work?

System.Reflection.MethodBase.GetCurrentMethod()

Returns a MethodBase object representing the currently executing method.

Namespace: System.Reflection

Assembly: mscorlib (in mscorlib.dll)

http://msdn.microsoft.com/en-us/library/system.reflection.methodbase.getcurrentmethod.aspx

Most efficient way to concatenate strings in JavaScript?

I have no comment on the concatenation itself, but I'd like to point out that @Jakub Hampl's suggestion:

For building strings in the DOM, in some cases it might be better to iteratively add to the DOM, rather then add a huge string at once.

is wrong, because it's based on a flawed test. That test never actually appends into the DOM.

This fixed test shows that creating the string all at once before rendering it is much, MUCH faster. It's not even a contest.

(Sorry this is a separate answer, but I don't have enough rep to comment on answers yet.)

How to reverse apply a stash?

I had a similar issue myself, I think all you need to do is git reset --hard and you will not lose your changes or any untracked changes.

If you read the docs in git stash --help it states that apply is "Like pop, but do not remove the state from the stash list" so the state still resides there, you can get it back.

Alternatively, if you have no conflicts, you can just git stash again after testing your changes.

If you do have conflicts, don't worry, git reset --hard won't lose them, as "Applying the state can fail with conflicts; in this case, it is not removed from the stash list. You need to resolve the conflicts by hand and call git stash drop manually afterwards."

Grep only the first match and stop

-m 1 means return the first match in any given file. But it will still continue to search in other files. Also, if there are two or more matched in the same line, all of them will be displayed.

You can use head -1 to solve this problem:

grep -o -a -m 1 -h -r "Pulsanti Operietur" /path/to/dir | head -1

explanation of each grep option:

-o, --only-matching, print only the matched part of the line (instead of the entire line)
-a, --text, process a binary file as if it were text
-m 1, --max-count, stop reading a file after 1 matching line
-h, --no-filename, suppress the prefixing of file names on output
-r, --recursive, read all files under a directory recursively

How to change an Eclipse default project into a Java project

Another possible way is to delete the project from Eclipse (but don't delete the project contents from disk!) and then use the New Java Project wizard to create a project in-place. That wizard will detect the Java code and set up build paths automatically.

Python: printing a file to stdout

To improve on @bgporter's answer, with Python-3 you will probably want to operate on bytes instead of needlessly converting things to utf-8:

>>> import shutil
>>> import sys
>>> with open("test.txt", "rb") as f:
...    shutil.copyfileobj(f, sys.stdout.buffer)

java.lang.NoClassDefFoundError: com/fasterxml/jackson/core/JsonFactory

You have to add one jar : jackson-annotations-2.1.2.jar You can download it from here and add it to the class path If you are using the gradle then add the following dependency.

compile 'com.fasterxml.jackson.jaxrs:jackson-jaxrs-json-provider:2.5.2'

Resource interpreted as Document but transferred with MIME type application/zip

I had this issue in an ASP web site project. Adding a "Content-Length" header caused downloads to start working again in Chrome.

E: Unable to locate package npm

Encountered this in Ubuntu for Windows, try running first

sudo apt-get update
sudo apt-get upgrade

then

sudo apt-get install npm

Static Classes In Java

Yes there is a static nested class in java. When you declare a nested class static, it automatically becomes a stand alone class which can be instantiated without having to instantiate the outer class it belongs to.

Example:

public class A
{

 public static class B
 {
 }
}

Because class B is declared static you can explicitly instantiate as:

B b = new B();

Note if class B wasn't declared static to make it stand alone, an instance object call would've looked like this:

A a= new A();
B b = a.new B();

How to get the Display Name Attribute of an Enum member via MVC Razor code?

In .NET5, I used DisplayTextFor without needing helper or extension methods:

@Html.DisplayTextFor(m => m.SomeEnumProperty)

Where SomeEnumProperty has a value of:

public enum MyEnum
{
    [Display(Name = "Not started")]
    NotStarted = 0,
    [Display(Name = "Weird display name instead of just 'Started'")]
    Started = 1,
}

How to sort with lambda in Python

Use

a = sorted(a, key=lambda x: x.modified, reverse=True)
#             ^^^^

On Python 2.x, the sorted function takes its arguments in this order:

sorted(iterable, cmp=None, key=None, reverse=False)

so without the key=, the function you pass in will be considered a cmp function which takes 2 arguments.

Hive: Filtering Data between Specified Dates when Date is a String

Try this:

select * from your_table
where date >= '2020-10-01'  

What is the default stack size, can it grow, how does it work with garbage collection?

How much a stack can grow?

You can use a VM option named ss to adjust the maximum stack size. A VM option is usually passed using -X{option}. So you can use java -Xss1M to set the maximum of stack size to 1M.

Each thread has at least one stack. Some Java Virtual Machines(JVM) put Java stack(Java method calls) and native stack(Native method calls in VM) into one stack, and perform stack unwinding using a Managed to Native Frame, known as M2NFrame. Some JVMs keep two stacks separately. The Xss set the size of the Java Stack in most cases.

For many JVMs, they put different default values for stack size on different platforms.

Can we limit this growth?

When a method call occurs, a new stack frame will be created on the stack of that thread. The stack will contain local variables, parameters, return address, etc. In java, you can never put an object on stack, only object reference can be stored on stack. Since array is also an object in java, arrays are also not stored on stack. So, if you reduce the amount of your local primitive variables, parameters by grouping them into objects, you can reduce the space on stack. Actually, the fact that we cannot explicitly put objects on java stack affects the performance some time(cache miss).

Does stack has some default minimum value or default maximum value?

As I said before, different VMs are different, and may change over versions. See here.

how does garbage collection work on stack?

Garbage collections in Java is a hot topic. Garbage collection aims to collect unreachable objects in the heap. So that needs a definition of 'reachable.' Everything on the stack constitutes part of the root set references in GC. Everything that is reachable from every stack of every thread should be considered as live. There are some other root set references, like Thread objects and some class objects.

This is only a very vague use of stack on GC. Currently most JVMs are using a generational GC. This article gives brief introduction about Java GC. And recently I read a very good article talking about the GC on .net. The GC on oracle jvm is quite similar so I think that might also help you.

Required request body content is missing: org.springframework.web.method.HandlerMethod$HandlerMethodParameter

If it's working from Postman, try new Spring version, becouse the 'org.springframework.boot' 2.2.2.RELEASE version can throw "Required request body content is missing" exception.
Try 2.2.6.RELEASE version.

Script to get the HTTP status code of a list of urls?

This relies on widely available wget, present almost everywhere, even on Alpine Linux.

wget --server-response --spider --quiet "${url}" 2>&1 | awk 'NR==1{print $2}'

The explanations are as follow :

--quiet

Turn off Wget's output.

Source - wget man pages

--spider

[ ... ] it will not download the pages, just check that they are there. [ ... ]

Source - wget man pages

--server-response

Print the headers sent by HTTP servers and responses sent by FTP servers.

Source - wget man pages

What they don't say about --server-response is that those headers output are printed to standard error (sterr), thus the need to redirect to stdin.

The output sent to standard input, we can pipe it to awk to extract the HTTP status code. That code is :

  • the second ($2) non-blank group of characters: {$2}
  • on the very first line of the header: NR==1

And because we want to print it... {print $2}.

wget --server-response --spider --quiet "${url}" 2>&1 | awk 'NR==1{print $2}'

How to load data from a text file in a PostgreSQL database?

The slightly modified version of COPY below worked better for me, where I specify the CSV format. This format treats backslash characters in text without any fuss. The default format is the somewhat quirky TEXT.

COPY myTable FROM '/path/to/file/on/server' ( FORMAT CSV, DELIMITER('|') );

Emulate Samsung Galaxy Tab

If you are developing on Netbeans, you will not get the Third-Party add-ons. You can download the Skins directly from Samsung here: http://developer.samsung.com/android/tools-sdks

After download, unzip to ...\Android\android-sdk\add-ons[name of device]

Restart the Android SDK Manager, and the new device should be there under Extras.

It would be better to add the download site directly to the SDK...if anyone knows it, please post it.

Scott

How to calculate the IP range when the IP address and the netmask is given?

my good friend Alessandro have a nice post regarding bit operators in C#, you should read about it so you know what to do.

It's pretty easy. If you break down the IP given to you to binary, the network address is the ip address where all of the host bits (the 0's in the subnet mask) are 0,and the last address, the broadcast address, is where all the host bits are 1.

For example:

ip 192.168.33.72 mask 255.255.255.192

11111111.11111111.11111111.11000000 (subnet mask)
11000000.10101000.00100001.01001000 (ip address)

The bolded parts is the HOST bits (the rest are network bits). If you turn all the host bits to 0 on the IP, you get the first possible IP:

11000000.10101000.00100001.01000000 (192.168.33.64)

If you turn all the host bits to 1's, then you get the last possible IP (aka the broadcast address):

11000000.10101000.00100001.01111111 (192.168.33.127)

So for my example:

the network is "192.168.33.64/26":
Network address: 192.168.33.64
First usable: 192.168.33.65 (you can use the network address, but generally this is considered bad practice)
Last useable: 192.168.33.126
Broadcast address: 192.168.33.127

Find (and kill) process locking port 3000 on Mac

A one-liner to extract the PID of the process using port 3000 and kill it.

lsof -ti:3000 | xargs kill

The -t flag removes everything but the PID from the lsof output, making it easy to kill it.

Can't clone a github repo on Linux via HTTPS

As JERC said, make sure you have an updated version of git. If you are only using the default settings, when you try to install git you will get version 1.7.1. Other than manually downloading and installing the latest version of get, you can also accomplish this by adding a new repository to yum.

From tecadmin.net:

Download and install the rpmforge repository:

# use this for 64-bit
rpm -i 'http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.5.3-1.el6.rf.x86_64.rpm'
# use this for 32-bit
rpm -i 'http://pkgs.repoforge.org/rpmforge-release/rpmforge-release-0.5.3-1.el6.rf.i686.rpm'

# then run this in either case
rpm --import http://apt.sw.be/RPM-GPG-KEY.dag.txt

Then you need to enable the rpmforge-extras. Edit /etc/yum.repos.d/rpmforge.repo and change enabled = 0 to enabled = 1 under [rpmforge-extras]. The file looks like this:

### Name: RPMforge RPM Repository for RHEL 6 - dag
### URL: http://rpmforge.net/
[rpmforge]
name = RHEL $releasever - RPMforge.net - dag
baseurl = http://apt.sw.be/redhat/el6/en/$basearch/rpmforge
mirrorlist = http://mirrorlist.repoforge.org/el6/mirrors-rpmforge
#mirrorlist = file:///etc/yum.repos.d/mirrors-rpmforge
enabled = 1
protect = 0
gpgkey = file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmforge-dag
gpgcheck = 1

[rpmforge-extras]
name = RHEL $releasever - RPMforge.net - extras
baseurl = http://apt.sw.be/redhat/el6/en/$basearch/extras
mirrorlist = http://mirrorlist.repoforge.org/el6/mirrors-rpmforge-extras
#mirrorlist = file:///etc/yum.repos.d/mirrors-rpmforge-extras
enabled = 0 ####### CHANGE THIS LINE TO "enabled = 1" #############
protect = 0
gpgkey = file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmforge-dag
gpgcheck = 1

[rpmforge-testing]
name = RHEL $releasever - RPMforge.net - testing
baseurl = http://apt.sw.be/redhat/el6/en/$basearch/testing
mirrorlist = http://mirrorlist.repoforge.org/el6/mirrors-rpmforge-testing
#mirrorlist = file:///etc/yum.repos.d/mirrors-rpmforge-testing
enabled = 0
protect = 0
gpgkey = file:///etc/pki/rpm-gpg/RPM-GPG-KEY-rpmforge-dag
gpgcheck = 1

Once you've done this, then you can update git with

yum update git

I'm not sure why, but they then suggest disabling rpmforge-extras (change back to enabled = 0) and then running yum clean all.

Most likely you'll need to use sudo for these commands.

Fastest way to get the first n elements of a List into an Array

It mostly depends on how big n is.

If n==0, nothing beats option#1 :)

If n is very large, toArray(new String[n]) is faster.

Understanding slice notation

Index:
      ------------>
  0   1   2   3   4
+---+---+---+---+---+
| a | b | c | d | e |
+---+---+---+---+---+
  0  -4  -3  -2  -1
      <------------

Slice:
    <---------------|
|--------------->
:   1   2   3   4   :
+---+---+---+---+---+
| a | b | c | d | e |
+---+---+---+---+---+
:  -4  -3  -2  -1   :
|--------------->
    <---------------|

I hope this will help you to model the list in Python.

Reference: http://wiki.python.org/moin/MovingToPythonFromOtherLanguages

Getting the client IP address: REMOTE_ADDR, HTTP_X_FORWARDED_FOR, what else could be useful?

In addition to REMOTE_ADDR and HTTP_X_FORWARDED_FOR there are some other headers that can be set such as:

  • HTTP_CLIENT_IP
  • HTTP_X_FORWARDED_FOR can be comma delimited list of IPs
  • HTTP_X_FORWARDED
  • HTTP_X_CLUSTER_CLIENT_IP
  • HTTP_FORWARDED_FOR
  • HTTP_FORWARDED

I found the code on the following site useful:
http://www.grantburton.com/?p=97

Change the jquery show()/hide() animation?

You can also use a fadeIn/FadeOut Combo, too....

$('.test').bind('click', function(){
    $('.div1').fadeIn(500); 
    $('.div2').fadeOut(500);
    $('.div3').fadeOut(500);
    return false;
});

java.lang.IllegalAccessError: tried to access method

If getData is protected then try making it public. The problem could exist in JAVA 1.6 and be absent in 1.5x

I got this for your problem. Illegal access error

Multiple conditions in a C 'for' loop

Wikipedia tells what comma operator does:

"In the C and C++ programming languages, the comma operator (represented by the token ,) is a binary operator that evaluates its first operand and discards the result, and then evaluates the second operand and returns this value (and type)."

How to print all key and values from HashMap in Android?

Kotlin Answer

for ((key, value) in map.entries) {
    // do something with `key`
    // so something with `value`
}

You may find other solutions that include filterValues. Just keep in mind that retrieving a Key value using filterValues will include braces [].

val key = map.filterValues {it = position}.keys

Java 8 lambda get and remove element from list

When we want to get multiple elements from a List into a new list (filter using a predicate) and remove them from the existing list, I could not find a proper answer anywhere.

Here is how we can do it using Java Streaming API partitioning.

Map<Boolean, List<ProducerDTO>> classifiedElements = producersProcedureActive
    .stream()
    .collect(Collectors.partitioningBy(producer -> producer.getPod().equals(pod)));

// get two new lists 
List<ProducerDTO> matching = classifiedElements.get(true);
List<ProducerDTO> nonMatching = classifiedElements.get(false);

// OR get non-matching elements to the existing list
producersProcedureActive = classifiedElements.get(false);

This way you effectively remove the filtered elements from the original list and add them to a new list.

Refer the 5.2. Collectors.partitioningBy section of this article.

Windows 7 - 'make' is not recognized as an internal or external command, operable program or batch file

  1. First make sure you have MinGW installed.
  2. From MinGW installation manager check if you have the mingw32-make package installed.
  3. Check if you have added the MinGW bin folder to your PATH. type PATH in your command line and look for the folder. Or on windows 10 go to Control Panel\System and Security\System --> Advanced system settings --> Environment Variables --> System Variables find Path variable, select, Edit and check if it is there. If not just add it!
  4. As explained here, create a new file in any of your PATH folders. For example create mingwstartup.bat in the MinGW bin folder. write the line doskey make=mingw32-make.exe inside, save and close it.
  5. open Registry Editor by running regedit. As explained here in HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER go to \Software\Microsoft\Command Processor right click on the right panel New --> Expandable String Value and name it AutoRun. double click and enter the path to your .bat file as the Value data (e.g. "C:\MinGW\bin\mingwstartup.bat") the result should look like this:

enter image description here

now every time you open a new terminal make command will run the mingw32-make.exe. I hope it helps.

P.S. If you don't want to see the commands of the .bat file to be printed out to the terminal put @echo off at the top of the batch file.

How to select a node of treeview programmatically in c#?

Apologies for my previously mixed up answer.

Here is how to do:

myTreeView.SelectedNode = myTreeNode;

(Update)

I have tested the code below and it works:

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        treeView1.Nodes.Add("1", "1");
        treeView1.Nodes.Add("2", "2");
        treeView1.Nodes[0].Nodes.Add("1-1", "1-1");
        TreeNode treeNode = treeView1.Nodes[0].Nodes.Add("1-2", "1-3");
        treeView1.SelectedNode = treeNode;
        MessageBox.Show(treeNode.IsSelected.ToString());
    }


}

Using @property versus getters and setters

Prefer properties. It's what they're there for.

The reason is that all attributes are public in Python. Starting names with an underscore or two is just a warning that the given attribute is an implementation detail that may not stay the same in future versions of the code. It doesn't prevent you from actually getting or setting that attribute. Therefore, standard attribute access is the normal, Pythonic way of, well, accessing attributes.

The advantage of properties is that they are syntactically identical to attribute access, so you can change from one to another without any changes to client code. You could even have one version of a class that uses properties (say, for code-by-contract or debugging) and one that doesn't for production, without changing the code that uses it. At the same time, you don't have to write getters and setters for everything just in case you might need to better control access later.

Less aggressive compilation with CSS3 calc

There is several escaping options with same result:

body { width: ~"calc(100% - 250px - 1.5em)"; }
body { width: calc(~"100% - 250px - 1.5em"); }
body { width: calc(100% ~"-" 250px ~"-" 1.5em); }

Android offline documentation and sample codes

here is direct link for api 17 documentation. Just extract at under docs folder. Hope it helps.

https://dl-ssl.google.com/android/repository/docs-17_r02.zip   (129 MB)

How do I pass variables and data from PHP to JavaScript?

Let's say your variable is always integer. In that case this is easier:

<?PHP
    $number = 4;

    echo '<script>';
    echo 'var number = ' . $number . ';';
    echo 'alert(number);';
    echo '</script>';
?>

Output:

<script>var number = 4;alert(number);</script>

Let's say your variable is not an integer, but if you try above method you will get something like this:

<script>var number = abcd;alert(number);</script>

But in JavaScript this is a syntax error.

So in PHP we have a function call json_encode that encode string to a JSON object.

<?PHP
    $number = 'abcd';

    echo '<script>';
    echo 'var number = ' . json_encode($number) . ';';
    echo 'alert(number);';
    echo '</script>';
?>

Since abcd in JSON is "abcd", it looks like this:

<script>var number = "abcd";alert(number);</script>

You can use same method for arrays:

<?PHP
    $details = [
    'name' => 'supun',
    'age' => 456,
    'weight' => '55'
    ];

    echo '<script>';
    echo 'var details = ' . json_encode($details) . ';';
    echo 'alert(details);';
    echo 'console.log(details);';
    echo '</script>';
?>

And your JavaScript code looks like this:

<script>var details = {"name":"supun","age":456,"weight":"55"};alert(details);console.log(details);</script>

Console output

Enter image description here

regular expression for Indian mobile numbers

This is worked for me using JAVA script for chrome extension.

document.body.innerHTML = myFunction();
function myFunction()
{
    var phonedef = new RegExp("(?:(?:\\+|0{0,2})91(\\s*[\\- ]\\s*)?|[0 ]?)?[789]\\d{9}|(\\d[ -]?){10}\\d", "g");

    var str = document.body.innerHTML; 
    var res = str.replace(phonedef, function myFunction(x){return "<a href='tel:"+x.replace( /(\s|-)/g, "")+"'>"+x+"</a>";});

    return res;
}

This covers following numbers pattern

9883443344
8888564723 
7856128945

09883443344 
0 9883443344 
0-9883443344

919883443344 
91 8834433441 
91-9883443344 
91 -9883443344 
91- 9883443344 
91 - 9883443344 
91 -9883443344

+917878525200 
+91 8834433441 
+91-9883443344 
+91 -9883443344 
+91- 9883443344 
+91 - 9883443344 
+91 -9883443344

0919883443344 
0091-7779015989 
0091 - 8834433440 
022-24130000 
080 25478965 
0416-2565478 
08172-268032 
04512-895612 
02162-240000 
022-24141414 
079-22892350

GCC dump preprocessor defines

I usually do it this way:

$ gcc -dM -E - < /dev/null

Note that some preprocessor defines are dependent on command line options - you can test these by adding the relevant options to the above command line. For example, to see which SSE3/SSE4 options are enabled by default:

$ gcc -dM -E - < /dev/null | grep SSE[34]
#define __SSE3__ 1
#define __SSSE3__ 1

and then compare this when -msse4 is specified:

$ gcc -dM -E -msse4 - < /dev/null | grep SSE[34]
#define __SSE3__ 1
#define __SSE4_1__ 1
#define __SSE4_2__ 1
#define __SSSE3__ 1

Similarly you can see which options differ between two different sets of command line options, e.g. compare preprocessor defines for optimisation levels -O0 (none) and -O3 (full):

$ gcc -dM -E -O0 - < /dev/null > /tmp/O0.txt
$ gcc -dM -E -O3 - < /dev/null > /tmp/O3.txt
$ sdiff -s /tmp/O0.txt /tmp/O3.txt 
#define __NO_INLINE__ 1        <
                               > #define __OPTIMIZE__ 1

How to make a TextBox accept only alphabetic characters?

You could use the following snippet:

private void textBox1_TextChanged(object sender, EventArgs e)
{
    if (!System.Text.RegularExpressions.Regex.IsMatch(textBox1.Text, "^[a-zA-Z ]"))
    {
        MessageBox.Show("This textbox accepts only alphabetical characters");
        textBox1.Text.Remove(textBox1.Text.Length - 1);
    }
}

Play infinitely looping video on-load in HTML5

You can do this the following two ways:

1) Using loop attribute in video element (mentioned in the first answer):

2) and you can use the ended media event:

window.addEventListener('load', function(){
    var newVideo = document.getElementById('videoElementId');
    newVideo.addEventListener('ended', function() {
        this.currentTime = 0;
        this.play();
    }, false);

    newVideo.play();

});

Does HTML5 <video> playback support the .avi format?

The current HTML5 draft specification does not specify which video formats browsers should support in the video tag. User agents are free to support any video formats they feel are appropriate.

http://en.wikipedia.org/wiki/HTML5_video

Why is $$ returning the same id as the parent process?

Try getppid() if you want your C program to print your shell's PID.

How do I write a for loop in bash

I commonly like to use a slight variant on the standard for loop. I often use this to run a command on a series of remote hosts. I take advantage of bash's brace expansion to create for loops that allow me to create non-numerical for-loops.

Example:

I want to run the uptime command on frontend hosts 1-5 and backend hosts 1-3:

% for host in {frontend{1..5},backend{1..3}}.mycompany.com
    do ssh $host "echo -n $host; uptime"
  done

I typically run this as a single-line command with semicolons on the ends of the lines instead of the more readable version above. The key usage consideration are that braces allow you to specify multiple values to be inserted into a string (e.g. pre{foo,bar}post results in prefoopost, prebarpost) and allow counting/sequences by using the double periods (you can use a..z etc.). However, the double period syntax is a new feature of bash 3.0; earlier versions will not support this.

How to recursively find and list the latest modified files in a directory with subdirectories and times

This could be done with a recursive function in Bash too.

Let F be a function that displays the time of file which must be lexicographically sortable yyyy-mm-dd, etc., (OS-dependent?)

F(){ stat --format %y "$1";}                # Linux
F(){ ls -E "$1"|awk '{print$6" "$7}';}      # SunOS: maybe this could be done easier

R, the recursive function that runs through directories:

R(){ local f;for f in "$1"/*;do [ -d "$f" ]&&R $f||F "$f";done;}

And finally

for f in *;do [ -d "$f" ]&&echo `R "$f"|sort|tail -1`" $f";done

How to call C++ function from C?

You will have to write a wrapper for C in C++ if you want to do this. C++ is backwards compatible, but C is not forwards compatible.

Sending and receiving data over a network using TcpClient

First, I recommend that you use WCF, .NET Remoting, or some other higher-level communication abstraction. The learning curve for "simple" sockets is nearly as high as WCF, because there are so many non-obvious pitfalls when using TCP/IP directly.

If you decide to continue down the TCP/IP path, then review my .NET TCP/IP FAQ, particularly the sections on message framing and application protocol specifications.

Also, use asynchronous socket APIs. The synchronous APIs do not scale and in some error situations may cause deadlocks. The synchronous APIs make for pretty little example code, but real-world production-quality code uses the asynchronous APIs.

Mipmap drawables for icons

res/
mipmap-mdpi/ic_launcher.png (48x48 pixels)
mipmap-hdpi/ic_launcher.png (72x72)
mipmap-xhdpi/ic_launcher.png (96x96)
mipmap-xxhdpi/ic_launcher.png (144x144)
mipmap-xxxhdpi/ic_launcher.png (192x192)

MipMap for app icon for launcher

http://android-developers.blogspot.co.uk/2014/10/getting-your-apps-ready-for-nexus-6-and.html

https://androidbycode.wordpress.com/2015/02/14/goodbye-launcher-drawables-hello-mipmaps/

Linux/Unix command to determine if process is running?

Putting the various suggestions together, the cleanest version I was able to come up with (without unreliable grep which triggers parts of words) is:

kill -0 $(pidof mysql) 2> /dev/null || echo "Mysql ain't runnin' message/actions"

kill -0 doesn't kill the process but checks if it exists and then returns true, if you don't have pidof on your system, store the pid when you launch the process:

$ mysql &
$ echo $! > pid_stored

then in the script:

kill -0 $(cat pid_stored) 2> /dev/null || echo "Mysql ain't runnin' message/actions"

Unix shell script find out which directory the script file resides?

As theMarko suggests:

BASEDIR=$(dirname $0)
echo $BASEDIR

This works unless you execute the script from the same directory where the script resides, in which case you get a value of '.'

To get around that issue use:

current_dir=$(pwd)
script_dir=$(dirname $0)

if [ $script_dir = '.' ]
then
script_dir="$current_dir"
fi

You can now use the variable current_dir throughout your script to refer to the script directory. However this may still have the symlink issue.

There is no tracking information for the current branch

git branch --set-upstream-to=origin/main

Placing border inside of div and not on its edge

Yahoo! This is really possible. I found it.

For Bottom Border:

div {box-shadow: 0px -3px 0px red inset; }

For Top Border:

div {box-shadow: 0px 3px 0px red inset; }

How To Make Circle Custom Progress Bar in Android

I'd make a new view class and derive from the existing ProgressBar. Then override the onDraw function. You're going to need to make direct draw calls to the canvas for this, since its so custom- a combination of drawText, drawArc, and drawOval should do it- an oval for the outer ring and empty portions, and an arc for the colored in parts. You may end up needing to override onMeasure and onLayout as well. Then in your xml, reference this view by class name like this when you want to use it.

How to select the last column of dataframe

Just to add to @Anshul Singh Suryan's answer:

When we split the dataframe to just get the last column:

If we split like:

y = df.iloc[:,-1:] - y remains a dataframe

However, if we split like

y = df.iloc[:,-1] - y becomes a Series.

This is a notable difference that I've found in the two approaches. If you don't care about the resultant type, you can use either of the two. Otherwise you need to take care of the above findings.

This is applicable for any number of rows you want to extract and not just the last row. For example, if you want last n number of rows of a dataframe, where n is any integer less than or equal to the number of columns present in the dataframe, then you can easily do the following:

y = df.iloc[:,n:]

Replace n by the number of columns you want. Same is true for rows as well.

How to access private data members outside the class without making "friend"s?

friend is your friend.

class A{
    friend void foo(A arg);
    int iData;
};

void foo(A arg){
     // can access a.iData here
}

If you're doing this regularly you should probably reconsider your design though.

How to compare a local git branch with its remote branch?

If you're on a given branch, and you want to compare your working copy with the upstream branch you're tracking, use:

git diff @{upstream}

If you want to compare your current HEAD with the upstream branch (thanks @Arijoon):

git diff @ @{upstream}

If your upstream isn't set, you can use @{push} to get a diff against the branch you are set to push to (also from @Arijoon's comment):

git diff @{push}

Courtesy of this answer, the git documentation for specifying revisions has:

<branchname>@{upstream}, e.g. master@{upstream}, @{u}
The suffix @{upstream} to a branchname (short form <branchname>@{u}) refers to the branch that the branch specified by branchname is set to build on top of (configured with branch.<name>.remote and branch.<name>.merge). A missing branchname defaults to the current one.

Twitter bootstrap 3 two columns full height

You can achieve what you want with the padding-bottom: 100%; margin-bottom: -100%; trick, has you can see in this fiddle.

I change your HTML a little bit, but you can achieve the same result with your own HTML with the following code

.col-md-9 {
    overflow: hidden;
}

.col-md-3 {
    padding-bottom: 100%;
    margin-bottom: -100%;
}

@Value annotation type casting to Integer from String

I was looking for the answer on internet and I found the following

@Value("#{new java.text.SimpleDateFormat('${aDateFormat}').parse('${aDateStr}')}")
Date myDate;

So in your case you could try with this

@Value("#{new Integer('${api.orders.pingFrequency}')}")
private Integer pingFrequency;

How can I make space between two buttons in same div?

Dragan B. solution is correct. In my case I needed the buttons to be spaced vertically when stacking so I added the mb-2 property to them.

<div class="btn-toolbar">
   <button type="button" class="btn btn-primary mr-2 mb-2">First</button>
   <button type="button" class="btn btn-primary mr-2 mb-2">Second</button>
   <button type="button" class="btn btn-primary mr-2 mb-2">Third</button>
</div>

How to find and replace string?

Here's the version I ended up writing that replaces all instances of the target string in a given string. Works on any string type.

template <typename T, typename U>
T &replace (
          T &str, 
    const U &from, 
    const U &to)
{
    size_t pos;
    size_t offset = 0;
    const size_t increment = to.size();

    while ((pos = str.find(from, offset)) != T::npos)
    {
        str.replace(pos, from.size(), to);
        offset = pos + increment;
    }

    return str;
}

Example:

auto foo = "this is a test"s;
replace(foo, "is"s, "wis"s);
cout << foo;

Output:

thwis wis a test

Note that even if the search string appears in the replacement string, this works correctly.

How to hide close button in WPF window?

I was trying Viachaslau's answer since I like the idea of not removing the button but disabling it, but for some reason it did not always work: the close button was still enabled but no errors whatsoever.

This on the other hand always worked (error checking omitted):

[DllImport( "user32.dll" )]
private static extern IntPtr GetSystemMenu( IntPtr hWnd, bool bRevert );
[DllImport( "user32.dll" )]
private static extern bool EnableMenuItem( IntPtr hMenu, uint uIDEnableItem, uint uEnable );

private const uint MF_BYCOMMAND = 0x00000000;
private const uint MF_GRAYED = 0x00000001;
private const uint SC_CLOSE = 0xF060;
private const int WM_SHOWWINDOW = 0x00000018;

protected override void OnSourceInitialized( EventArgs e )
{
  base.OnSourceInitialized( e );
  var hWnd = new WindowInteropHelper( this );
  var sysMenu = GetSystemMenu( hWnd.Handle, false );
  EnableMenuItem( sysMenu, SC_CLOSE, MF_BYCOMMAND | MF_GRAYED );
}

Base64 PNG data to HTML5 canvas

Jerryf's answer is fine, except for one flaw.

The onload event should be set before the src. Sometimes the src can be loaded instantly and never fire the onload event.

(Like Totty.js pointed out.)

var canvas = document.getElementById("c");
var ctx = canvas.getContext("2d");

var image = new Image();
image.onload = function() {
    ctx.drawImage(image, 0, 0);
};
image.src = "data:image/  png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUAAAAFCAIAAAACDbGyAAAAAXNSR0IArs4c6QAAAAlwSFlzAAALEwAACxMBAJqcGAAAAAd0SU1FB9oMCRUiMrIBQVkAAAAZdEVYdENvbW1lbnQAQ3JlYXRlZCB3aXRoIEdJTVBXgQ4XAAAADElEQVQI12NgoC4AAABQAAEiE+h1AAAAAElFTkSuQmCC";

How can get the text of a div tag using only javascript (no jQuery)

Actually you dont need to call document.getElementById() function to get access to your div.

You can use this object directly by id:

text = test.textContent || test.innerText;
alert(text);

How do I escape double and single quotes in sed?

May be the "\" char, try this one:

sed 's/\"http:\/\/www.fubar.com\"/URL_FUBAR/g'

Python PDF library

There is also http://appyframework.org/pod.html which takes a LibreOffice or OpenOffice document as template and can generate pdf, rtf, odt ... To generate pdf it requires a headless OOo on some server. Documentation is concise but relatively complete. http://appyframework.org/podWritingTemplates.html If you need advice, the author is rather helpful.

Use Mockito to mock some methods but not others

Partial mocking using Mockito's spy method could be the solution to your problem, as already stated in the answers above. To some degree I agree that, for your concrete use case, it may be more appropriate to mock the DB lookup. From my experience this is not always possible - at least not without other workarounds - that I would consider as being very cumbersome or at least fragile. Note, that partial mocking does not work with ally versions of Mockito. You have use at least 1.8.0.

I would have just written a simple comment for the original question instead of posting this answer, but StackOverflow does not allow this.

Just one more thing: I really cannot understand that many times a question is being asked here gets comment with "Why you want to do this" without at least trying to understand the problem. Escpecially when it comes to then need for partial mocking there are really a lot of use cases that I could imagine where it would be useful. That's why the guys from Mockito provided that functionality. This feature should of course not be overused. But when we talk about test case setups that otherwise could not be established in a very complicated way, spying should be used.

Selecting with complex criteria from pandas.DataFrame

You can use pandas it has some built in functions for comparison. So if you want to select values of "A" that are met by the conditions of "B" and "C" (assuming you want back a DataFrame pandas object)

df[['A']][df.B.gt(50) & df.C.ne(900)]

df[['A']] will give you back column A in DataFrame format.

pandas 'gt' function will return the positions of column B that are greater than 50 and 'ne' will return the positions not equal to 900.

Quickly create a large file on a Linux system

This is a common question -- especially in today's environment of virtual environments. Unfortunately, the answer is not as straight-forward as one might assume.

dd is the obvious first choice, but dd is essentially a copy and that forces you to write every block of data (thus, initializing the file contents)... And that initialization is what takes up so much I/O time. (Want to make it take even longer? Use /dev/random instead of /dev/zero! Then you'll use CPU as well as I/O time!) In the end though, dd is a poor choice (though essentially the default used by the VM "create" GUIs). E.g:

dd if=/dev/zero of=./gentoo_root.img bs=4k iflag=fullblock,count_bytes count=10G

truncate is another choice -- and is likely the fastest... But that is because it creates a "sparse file". Essentially, a sparse file is a section of disk that has a lot of the same data, and the underlying filesystem "cheats" by not really storing all of the data, but just "pretending" that it's all there. Thus, when you use truncate to create a 20 GB drive for your VM, the filesystem doesn't actually allocate 20 GB, but it cheats and says that there are 20 GB of zeros there, even though as little as one track on the disk may actually (really) be in use. E.g.:

 truncate -s 10G gentoo_root.img

fallocate is the final -- and best -- choice for use with VM disk allocation, because it essentially "reserves" (or "allocates" all of the space you're seeking, but it doesn't bother to write anything. So, when you use fallocate to create a 20 GB virtual drive space, you really do get a 20 GB file (not a "sparse file", and you won't have bothered to write anything to it -- which means virtually anything could be in there -- kind of like a brand new disk!) E.g.:

fallocate -l 10G gentoo_root.img

Uncaught TypeError: Cannot read property 'msie' of undefined

$.browser was removed from jQuery starting with version 1.9. It is now available as a plugin. It's generally recommended to avoid browser detection, which is why it was removed.

How to store and retrieve a dictionary with redis

You can do it by hmset (multiple keys can be set using hmset).

hmset("RedisKey", dictionaryToSet)

import redis
conn = redis.Redis('localhost')

user = {"Name":"Pradeep", "Company":"SCTL", "Address":"Mumbai", "Location":"RCP"}

conn.hmset("pythonDict", user)

conn.hgetall("pythonDict")

{'Company': 'SCTL', 'Address': 'Mumbai', 'Location': 'RCP', 'Name': 'Pradeep'}

MySQL: How to copy rows, but change a few fields?

INSERT INTO Table
          ( Event_ID
          , col2
           ...
          )
     SELECT "155"
          , col2
           ...
      FROM Table WHERE Event_ID = "120"

Here, the col2, ... represent the remaining columns (the ones other than Event_ID) in your table.

MySQL Removing Some Foreign keys

The foreign keys are there to ensure data integrity, so you can't drop a column as long as it's part of a foreign key. You need to drop the key first.

I would think the following query would do it:

ALTER TABLE assignmentStuff DROP FOREIGN KEY assignmentIDX;

Python & Matplotlib: Make 3D plot interactive in Jupyter Notebook

For 3-D visualization pythreejs is the best way to go probably in the notebook. It leverages the interactive widget infrastructure of the notebook, so connection between the JS and python is seamless.

A more advanced library is bqplot which is a d3-based interactive viz library for the iPython notebook, but it only does 2D

Entity Framework - Linq query with order by and group by

Try moving the order by after group by:

var groupByReference = (from m in context.Measurements
                        group m by new { m.Reference } into g
                        order by g.Avg(i => i.CreationTime)
                        select g).Take(numOfEntries).ToList();

How do I pass command-line arguments to a WinForms application?

You use this signature: (in c#) static void Main(string[] args)

This article may help to explain the role of the main function in programming as well: http://en.wikipedia.org/wiki/Main_function_(programming)

Here is a little example for you:

class Program
{
    static void Main(string[] args)
    {
        bool doSomething = false;

        if (args.Length > 0 && args[0].Equals("doSomething"))
            doSomething = true;

        if (doSomething) Console.WriteLine("Commandline parameter called");
    }
}

IntelliJ show JavaDocs tooltip on mouse over

From IntelliJ Ultimate 2018.1.5, aka IntelliJ IDEA 2018.1.5, till 2019.3 , there are actually two options under File -> Preferences:

  1. In Editor > General > Other (section) > Show quick documentation on mouse move - delay 500 ms
    • Select this check box to show quick documentation for the symbol at caret. The quick documentation pop-up window appears after the specified delay.
  2. In Editor > General > Code Completion (sub-item) > Auto-display documentation in 1000 ms
    • Select this check box to have IntelliJ IDEA automatically show a pop-up window with the documentation for the class, method, or field currently highlighted in the lookup list. If this check box is not selected, use Ctrl+Q to show quick documentation for the element at caret.
    • Quick documentation window will automatically pop up with the specified delay in those cases only, when code completion has been invoked explicitly. For the automatic code completion list, documentation window will only show up on pressing Ctrl+Q.

How to check if internet connection is present in Java?

URL url=new URL("http://[any domain]");
URLConnection con=url.openConnection();

/*now errors WILL arise here, i hav tried myself and it always shows "connected" so we'll open an InputStream on the connection, this way we know for sure that we're connected to d internet */

/* Get input stream */
con.getInputStream();

Put the above statements in try catch blocks and if an exception in caught means that there's no internet connection established. :-)

From milliseconds to hour, minutes, seconds and milliseconds

milliseconds = x
total = 0
while (milliseconds >= 1000) {
  milliseconds = (milliseconds - 1000)
  total = total + 1
}
hr = 0
min = 0
while (total >= 60) {
  total = total - 60
  min = min + 1
  if (min >= 60) hr = hr + 1
  if (min == 60) min = 0
}
sec = total

This is on groovy, but I thing that this is not problem for you. Method work perfect.

Truncating a table in a stored procedure

All DDL statements in Oracle PL/SQL should use Execute Immediate before the statement. Hence you should use:

execute immediate 'truncate table schema.tablename';

Convert boolean result into number/integer

I created a JSperf comparison of all suggested answers.

TL;DR - the best option for all current browsers is:

val | 0;

.

Update:

It seems like these days they are all pretty identical, except that the Number() function is the slowest, while the best being val === true ? 1 : 0;.

How to make div go behind another div?

You need to add z-index to the divs, with a positive number for the top div and negative for the div below

example

Why can't I center with margin: 0 auto?

An inline-block covers the whole line (from left to right), so a margin left and/or right won't work here. What you need is a block, a block has borders on the left and the right so can be influenced by margins.

This is how it works for me:

#content {
display: block;
margin: 0 auto;
}

Detecting superfluous #includes in C/C++?

Gimpel Software's PC Lint can report on when an include file has been included more than once in a compilation unit, but it can't find include files which are not needed in the way you are looking for.

Edit: It can. See itsmatt's answer

How can I get the timezone name in JavaScript?

This gets the timezone code (e.g., GMT) in older javascript (I'm using google app script with old engine):

function getTimezoneName() {
  return new Date().toString().get(/\((.+)\)/);
}

I'm just putting this here in case someone needs it.