Programs & Examples On #Newtons method

In numerical analysis, Newton's method (also known as the Newton–Raphson method) is a method for finding successively better approximations to the roots (or zeroes) of a real-valued function.

Writing your own square root function

It's a common interview question asked by Facebook etc. I don't think it's a good idea to use the Newton's method in an interview. What if the interviewer ask you the mechanism of the Newton's method when you don't really understand it?

I provided a binary search based solution in Java which I believe everyone can understand.

public int sqrt(int x) {

    if(x < 0) return -1;
    if(x == 0 || x == 1) return x;

    int lowerbound = 1;
    int upperbound = x;
    int root = lowerbound + (upperbound - lowerbound)/2;

    while(root > x/root || root+1 <= x/(root+1)){
        if(root > x/root){
            upperbound = root;
        } else {
            lowerbound = root;
        }
        root = lowerbound + (upperbound - lowerbound)/2;
    }
    return root;
}

You can test my code here: leetcode: sqrt(x)

Finding the Eclipse Version Number

(Update September 2012):

MRT points out in the comments that "Eclipse Version" question references a .eclipseproduct in the main folder, and it contains:

name=Eclipse Platform
id=org.eclipse.platform
version=3.x.0

So that seems more straightforward than my original answer below.

Also, Neeme Praks mentions below that there is a eclipse/configuration/config.ini which includes a line like:

eclipse.buildId=4.4.1.M20140925-0400

Again easier to find, as those are Java properties set and found with System.getProperty("eclipse.buildId").


Original answer (April 2009)

For Eclipse Helios 3.6, you can deduce the Eclipse Platform version directly from the About screen:
It is a combination of the Eclipse global version and the build Id:

alt text

Here is an example for Eclipse 3.6M6:
The version would be: 3.6.0.v201003121448, after the version 3.6.0 and the build Id I20100312-1448 (an Integration build from March 12th, 2010 at 14h48

To see it more easily, click on "Plugin Details" and sort by Version.


Note: Eclipse3.6 has a brand new cool logo:

alt text

And you can see the build Id now being displayed during the loading step of the different plugin.

How do you check if a string is not equal to an object or other string value in java?

Change your code to:

System.out.println("AM or PM?"); 
Scanner TimeOfDayQ = new Scanner(System.in);
TimeOfDayStringQ = TimeOfDayQ.next();

if(!TimeOfDayStringQ.equals("AM") && !TimeOfDayStringQ.equals("PM")) { // <--
    System.out.println("Sorry, incorrect input.");
    System.exit(1);
}

...

if(Hours == 13){
    if (TimeOfDayStringQ.equals("AM")) {
        TimeOfDayStringQ = "PM"; // <--
    } else {
        TimeOfDayStringQ = "AM"; // <--
    }
            Hours = 1;
    }
 }

Regular expression for first and last name

So, with customer we create this crazy regex:

(^$)|(^([^\-!#\$%&\(\)\*,\./:;\?@\[\\\]_\{\|\}¨?“”€\+<=>§°\d\s¤®™©]| )+$)

jQuery attr('onclick')

Felix Kling's way will work, (actually beat me to the punch), but I was also going to suggest to use

$('#next').die().live('click', stopMoving);

this might be a better way to do it if you run into problems and strange behaviors when the element is clicked multiple times.

iOS 7 status bar back to iOS 6 default style in iPhone app?

This may be a overwhelming problem if you use Auto layout because you can not directly manipulate frames anymore. There is a simple solution without too much work.

I ended up writing an utility method in an Utility Class and called it from all the view controllers's viewDidLayoutSubviews Method.

+ (void)addStatusBarIfiOS7:(UIViewController *)vc
    {
        if (NSFoundationVersionNumber > NSFoundationVersionNumber_iOS_6_1) {
            CGRect viewFrame = vc.view.frame;
            if(viewFrame.origin.y == 20) {
                //If the view's y origin is already 20 then don't move it down.
                return;
            }
            viewFrame.origin.y+=20.0;
            viewFrame.size.height-= 20.0;
            vc.view.frame = viewFrame;
            [vc.view layoutIfNeeded];
        }
    }

Override your viewDidLayoutSubviews method in the view controller, where you want status bar. It will get you through the burden of Autolayout.

- (void)viewDidLayoutSubviews
{
    [[UIApplication sharedApplication]setStatusBarStyle:UIStatusBarStyleLightContent];
    [super viewDidLayoutSubviews];
    [MyUtilityClass addStatusBarIfiOS7:self];
}

Using setTimeout to delay timing of jQuery actions

.html() only takes a string OR a function as an argument, not both. Try this:

 $("#showDiv").click(function () {
     $('#theDiv').show(1000, function () {
         setTimeout(function () {
             $('#theDiv').html(function () {
                 setTimeout(function () {
                     $('#theDiv').html('Here is some replacement text');
                 }, 0);
                 setTimeout(function () {
                     $('#theDiv').html('More replacement text goes here');
                 }, 2500);
             });
         }, 2500);
     });
 }); //click function ends

jsFiddle example

Create a Dropdown List for MVC3 using Entity Framework (.edmx Model) & Razor Views && Insert A Database Record to Multiple Tables

Well, actually I'll have to say David is right with his solution, but there are some topics disturbing me:

  1. You should never send your model to the view => This is correct
  2. If you create a ViewModel, and include the Model as member in the ViewModel, then you effectively sent your model to the View => this is BAD
  3. Using dictionaries to send the options to the view => this not good style

So how can you create a better coupling?

I would use a tool like AutoMapper or ValueInjecter to map between ViewModel and Model. AutoMapper does seem to have the better syntax and feel to it, but the current version lacks a very severe topic: It is not able to perform the mapping from ViewModel to Model (under certain circumstances like flattening, etc., but this is off topic) So at present I prefer to use ValueInjecter.

So you create a ViewModel with the fields you need in the view. You add the SelectList items you need as lookups. And you add them as SelectLists already. So you can query from a LINQ enabled sourc, select the ID and text field and store it as a selectlist: You gain that you do not have to create a new type (dictionary) as lookup and you just move the new SelectList from the view to the controller.

  // StaffTypes is an IEnumerable<StaffType> from dbContext
  // viewModel is the viewModel initialized to copy content of Model Employee  
  // viewModel.StaffTypes is of type SelectList

  viewModel.StaffTypes =
    new SelectList(
        StaffTypes.OrderBy( item => item.Name )
        "StaffTypeID",
        "Type",
        viewModel.StaffTypeID
    );

In the view you just have to call

@Html.DropDownListFor( model => mode.StaffTypeID, model.StaffTypes )

Back in the post element of your method in the controller you have to take a parameter of the type of your ViewModel. You then check for validation. If the validation fails, you have to remember to re-populate the viewModel.StaffTypes SelectList, because this item will be null on entering the post function. So I tend to have those population things separated into a function. You just call back return new View(viewModel) if anything is wrong. Validation errors found by MVC3 will automatically be shown in the view.

If you have your own validation code you can add validation errors by specifying which field they belong to. Check documentation on ModelState to get info on that.

If the viewModel is valid you have to perform the next step:

If it is a create of a new item, you have to populate a model from the viewModel (best suited is ValueInjecter). Then you can add it to the EF collection of that type and commit changes.

If you have an update, you get the current db item first into a model. Then you can copy the values from the viewModel back to the model (again using ValueInjecter gets you do that very quick). After that you can SaveChanges and are done.

Feel free to ask if anything is unclear.

How can I debug a .BAT script?

A quite frequent issue is that a batch script is run by double-clicking its icon. Since the hosting Command Prompt (cmd.exe) instance also terminates as soon as the batch script is finished, it is not possible to read potential output and error messages.

To read such messages, it is very important that you explicitly open a Command Prompt window, manoeuvre to the applicable working directory and run the batch script by typing its path/name.

jQuery select option elements by value

function select_option(index)
{
    var optwewant;
    for (opts in $('#span_id').children('select'))
    {
        if (opts.value() = index)
        {
            optwewant = opts;
            break;
        }
    }
    alert (optwewant);
}

IIS7 Cache-Control

That's not true Jeff.

You simply have to select a folder within your IIS 7 Manager UI (e.g. Images or event the Default Web Application folder) and then click on "HTTP Response Headers". Then you have to click on "Set Common Header.." in the right pane and select the "Expire Web content". There you can easily configure a max-age of 24 hours by choosing "After:", entering "24" in the Textbox and choose "Hours" in the combobox.

Your first paragraph regarding the web.config entry is right. I'd add the cacheControlCustom-attribute to set the cache control header to "public" or whatever is needed in that case.

You can, of course, achieve the same by providing web.config entries (or files) as needed.

Edit: removed a confusing sentence :)

How to detect a USB drive has been plugged in?

It is easy to check for removable devices. However, there's no guarantee that it is a USB device:

var drives = DriveInfo.GetDrives()
    .Where(drive => drive.IsReady && drive.DriveType == DriveType.Removable);

This will return a list of all removable devices that are currently accessible. More information:

How do I use variables in Oracle SQL Developer?

I think that the Easiest way in your case is :

DEFINE EmpIDVar = 1234;

SELECT *
FROM Employees
WHERE EmployeeID = &EmpIDVar

For the string values it will be like :

DEFINE EmpIDVar = '1234';

SELECT *
FROM Employees
WHERE EmployeeID = '&EmpIDVar'

What do the crossed style properties in Google Chrome devtools mean?

In addition to the above answer I also want to highlight a case of striked out property which really surprised me.

If you are adding a background image to a div :

<div class = "myBackground">

</div>

You want to scale the image to fit in the dimensions of the div so this would be your normal class definition.

.myBackground {

 height:100px;
 width:100px;
 background: url("/img/bck/myImage.jpg") no-repeat; 
 background-size: contain;

}

but if you interchange the order as :-

.myBackground {
 height:100px;
 width:100px;
 background-size: contain;  //before the background
 background: url("/img/bck/myImage.jpg") no-repeat; 
}

then in chrome you ll see background-size as striked out. I am not sure why this is , but yeah you dont want to mess with it.

Is there a timeout for idle PostgreSQL connections?

if you are using postgresql 9.6+, then in your postgresql.conf you can set

idle_in_transaction_session_timeout = 30000 (msec)

C# - What does the Assert() method do? Is it still useful?

You should use it for times when you don't want to have to breakpoint every little line of code to check variables, but you do want to get some sort of feedback if certain situations are present, for example:

Debug.Assert(someObject != null, "someObject is null! this could totally be a bug!");

How to use multiple LEFT JOINs in SQL?

Yes it is possible. You need one ON for each join table.

LEFT JOIN ab
  ON ab.sht = cd.sht
LEFT JOIN aa
  ON aa.sht = cd.sht

Incidentally my personal formatting preference for complex SQL is described in http://bentilly.blogspot.com/2011/02/sql-formatting-style.html. If you're going to be writing a lot of this, it likely will help.

How to remove constraints from my MySQL table?

The simplest way to remove constraint is to use syntax ALTER TABLE tbl_name DROP CONSTRAINT symbol; introduced in MySQL 8.0.19:

As of MySQL 8.0.19, ALTER TABLE permits more general (and SQL standard) syntax for dropping and altering existing constraints of any type, where the constraint type is determined from the constraint name

ALTER TABLE tbl_magazine_issue DROP CONSTRAINT FK_tbl_magazine_issue_mst_users;

db<>fiddle demo

Can I delete data from the iOS DeviceSupport directory?

Yes, you can delete data from iOS device support by the symbols of the operating system, one for each version for each architecture. It's used for debugging. If you don't need to support those devices any more, you can delete the directory without ill effect

Unicode characters in URLs

Not sure if it is a good idea, but as mentioned in other comments and as I interpret it, many Unicode chars are valid in HTML5 URLs.

E.g., href docs say http://www.w3.org/TR/html5/links.html#attr-hyperlink-href:

The href attribute on a and area elements must have a value that is a valid URL potentially surrounded by spaces.

Then the definition of "valid URL" points to http://url.spec.whatwg.org/, which defines URL code points as:

ASCII alphanumeric, "!", "$", "&", "'", "(", ")", "*", "+", ",", "-", ".", "/", ":", ";", "=", "?", "@", "_", "~", and code points in the ranges U+00A0 to U+D7FF, U+E000 to U+FDCF, U+FDF0 to U+FFFD, U+10000 to U+1FFFD, U+20000 to U+2FFFD, U+30000 to U+3FFFD, U+40000 to U+4FFFD, U+50000 to U+5FFFD, U+60000 to U+6FFFD, U+70000 to U+7FFFD, U+80000 to U+8FFFD, U+90000 to U+9FFFD, U+A0000 to U+AFFFD, U+B0000 to U+BFFFD, U+C0000 to U+CFFFD, U+D0000 to U+DFFFD, U+E1000 to U+EFFFD, U+F0000 to U+FFFFD, U+100000 to U+10FFFD.

The term "URL code points" is then used in a few parts of the parsing algorithm, e.g. for the relative path state:

If c is not a URL code point and not "%", parse error.

Also the validator http://validator.w3.org/ passes for URLs like "??", and does not pass for URLs with characters like spaces "a b"

Related: Which characters make a URL invalid?

How to use graphics.h in codeblocks?

You don't only need the header file, you need the library that goes with it. Anyway, the include folder is not automatically loaded, you must configure your project to do so. Right-click on it : Build options > Search directories > Add. Choose your include folder, keep the path relative.

Edit For further assistance, please give details about the library you're trying to load (which provides a graphics.h file.)

how to set radio option checked onload with jQuery

This works for multiple radio buttons

$('input:radio[name="Aspirant.Gender"][value='+jsonData.Gender+']').prop('checked', true);

What is the difference between primary, unique and foreign key constraints, and indexes?

Primary Key: identify uniquely every row it can not be null. it can not be a duplicate.

Foreign Key: create relationship between two tables. can be null. can be a duplicate  

How can I download a specific Maven artifact in one command line?

The command:

mvn install:install-file 

Typically installs the artifact in your local repository, so you shouldn't need to download it. However, if you want to share your artifact with others, you will need to deploy the artifact to a central repository see the deploy plugin for more details.

Additionally adding a dependency to your POM will automatically fetch any third-party artifacts you need when you build your project. I.e. This will download the artifact from the central repository.

What is the difference between Document style and RPC style communication?

Can some body explain me the differences between a Document style and RPC style webservices?

There are two communication style models that are used to translate a WSDL binding to a SOAP message body. They are: Document & RPC

The advantage of using a Document style model is that you can structure the SOAP body any way you want it as long as the content of the SOAP message body is any arbitrary XML instance. The Document style is also referred to as Message-Oriented style.

However, with an RPC style model, the structure of the SOAP request body must contain both the operation name and the set of method parameters. The RPC style model assumes a specific structure to the XML instance contained in the message body.

Furthermore, there are two encoding use models that are used to translate a WSDL binding to a SOAP message. They are: literal, and encoded

When using a literal use model, the body contents should conform to a user-defined XML-schema(XSD) structure. The advantage is two-fold. For one, you can validate the message body with the user-defined XML-schema, moreover, you can also transform the message using a transformation language like XSLT.

With a (SOAP) encoded use model, the message has to use XSD datatypes, but the structure of the message need not conform to any user-defined XML schema. This makes it difficult to validate the message body or use XSLT based transformations on the message body.

The combination of the different style and use models give us four different ways to translate a WSDL binding to a SOAP message.

Document/literal
Document/encoded
RPC/literal
RPC/encoded

I would recommend that you read this article entitled Which style of WSDL should I use? by Russell Butek which has a nice discussion of the different style and use models to translate a WSDL binding to a SOAP message, and their relative strengths and weaknesses.

Once the artifacts are received, in both styles of communication, I invoke the method on the port. Now, this does not differ in RPC style and Document style. So what is the difference and where is that difference visible?

The place where you can find the difference is the "RESPONSE"!

RPC Style:

package com.sample;

import java.util.ArrayList;
import javax.jws.WebService;
import javax.jws.soap.SOAPBinding;
import javax.jws.soap.SOAPBinding.Style;

@WebService
@SOAPBinding(style=Style.RPC)
public interface StockPrice { 

    public String getStockPrice(String stockName); 

    public ArrayList getStockPriceList(ArrayList stockNameList); 
}

The SOAP message for second operation will have empty output and will look like:

RPC Style Response:

<ns2:getStockPriceListResponse 
       xmlns:ns2="http://sample.com/">
    <return/>
</ns2:getStockPriceListResponse>
</S:Body>
</S:Envelope>

Document Style:

package com.sample;

import java.util.ArrayList;
import javax.jws.WebService;
import javax.jws.soap.SOAPBinding;
import javax.jws.soap.SOAPBinding.Style;

@WebService
@SOAPBinding(style=Style.DOCUMENT)
public interface StockPrice {

    public String getStockPrice(String stockName);

    public ArrayList getStockPriceList(ArrayList stockNameList);
}

If we run the client for the above SEI, the output is:

123 [123, 456]

This output shows that ArrayList elements are getting exchanged between the web service and client. This change has been done only by the changing the style attribute of SOAPBinding annotation. The SOAP message for the second method with richer data type is shown below for reference:

Document Style Response:

<ns2:getStockPriceListResponse 
       xmlns:ns2="http://sample.com/">
<return xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
        xmlns:xs="http://www.w3.org/2001/XMLSchema"
        xsi:type="xs:string">123</return>
<return xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xmlns:xs="http://www.w3.org/2001/XMLSchema"
        xsi:type="xs:string">456</return>
</ns2:getStockPriceListResponse>
</S:Body>
</S:Envelope>

Conclusion

  • As you would have noticed in the two SOAP response messages that it is possible to validate the SOAP response message in case of DOCUMENT style but not in RPC style web services.
  • The basic disadvantage of using RPC style is that it doesn’t support richer data types and that of using Document style is that it brings some complexity in the form of XSD for defining the richer data types.
  • The choice of using one out of these depends upon the operation/method requirements and the expected clients.

Similarly, in what way SOAP over HTTP differ from XML over HTTP? After all SOAP is also XML document with SOAP namespace. So what is the difference here?

Why do we need a standard like SOAP? By exchanging XML documents over HTTP, two programs can exchange rich, structured information without the introduction of an additional standard such as SOAP to explicitly describe a message envelope format and a way to encode structured content.

SOAP provides a standard so that developers do not have to invent a custom XML message format for every service they want to make available. Given the signature of the service method to be invoked, the SOAP specification prescribes an unambiguous XML message format. Any developer familiar with the SOAP specification, working in any programming language, can formulate a correct SOAP XML request for a particular service and understand the response from the service by obtaining the following service details.

  • Service name
  • Method names implemented by the service
  • Method signature of each method
  • Address of the service implementation (expressed as a URI)

Using SOAP streamlines the process for exposing an existing software component as a Web service since the method signature of the service identifies the XML document structure used for both the request and the response.

(XML) The markup in the document following the root element must be well-formed. Start location: 6:2

In XML there can be only one root element - you have two - heading and song.

If you restructure to something like:

<?xml version="1.0" encoding="UTF-8"?>
<song> 
 <heading>
 The Twelve Days of Christmas
 </heading>
 ....
</song>

The error about well-formed XML on the root level should disappear (though there may be other issues).

How to link to a <div> on another page?

Create an anchor:

<a name="anchor" id="anchor"></a> 

then link to it:

<a href="http://server/page.html#anchor">Link text</a>

In Flask, What is request.args and how is it used?

@martinho as a newbie using Flask and Python myself, I think the previous answers here took for granted that you had a good understanding of the fundamentals. In case you or other viewers don't know the fundamentals, I'll give more context to understand the answer...

... the request.args is bringing a "dictionary" object for you. The "dictionary" object is similar to other collection-type of objects in Python, in that it can store many elements in one single object. Therefore the answer to your question

And how many parameters request.args.get() takes.

It will take only one object, a "dictionary" type of object (as stated in the previous answers). This "dictionary" object, however, can have as many elements as needed... (dictionaries have paired elements called Key, Value).

Other collection-type of objects besides "dictionaries", would be "tuple", and "list"... you can run a google search on those and "data structures" in order to learn other Python fundamentals. This answer is based Python; I don't have an idea if the same applies to other programming languages.

label or @html.Label ASP.net MVC 4

The helpers are there mainly to help you display labels, form inputs, etc for the strongly typed properties of your model. By using the helpers and Visual Studio Intellisense, you can greatly reduce the number of typos that you could make when generating a web page.

With that said, you can continue to create your elements manually for both properties of your view model or items that you want to display that are not part of your view model.

Query to select data between two dates with the format m/d/yyyy

DateTime dt1 = this.dateTimePicker1.Value.Date;
DateTime dt2 = this.dateTimePicker2.Value.Date.AddMinutes(1440);
String query = "SELECT * FROM student WHERE sdate BETWEEN '" + dt1 + "' AND '" + dt2 + "'";

Add custom icons to font awesome

I suggest keeping your icons separate from FontAwesome and create and maintain your own custom library. Personally, I think it is much easier to maintain keeping FontAwesome separate if you are going to be creating your own icon library. You can then have FontAwesome loaded into your site from a CDN and never have to worry about keeping it up-to-date.

When creating your own custom icons, create each icon via Adobe Illustrator or similar software. Once your icons are created, save each individually in SVG format on your computer.

Next, head on over to IcoMoon: http://icomoon.io , which has the best font generating software (in my opinion), and it's free. IcoMoon will allow you to import your individual svg-saved fonts into a font library, then generate your custom icon glyph library in eot, ttf, woff, and svg. One format IcoMoon does not generate is woff2.

After generating your icon pack at IcoMoon, head over to FontSquirrel: http://fontsquirrel.com and use their font generator. Use your ttf file generated at IcoMoon. In the newly generated icon pack created, you'll now have your icon pack in woff2 format.

Make sure the files for eot, ttf, svg, woff, and woff2 are all the same name. You are generating an icon pack from two different websites/software, and they do name their generated output differently.

You'll have CSS generated for your icon pack at both locations. But the CSS generated at IcoMoon will not include the woff2 format in your @font-face {} declaration. Make sure to add that when you're adding your CSS to your project:

@font-face {
    font-family: 'customiconpackname';
    src: url('../fonts/customiconpack.eot?lchn8y');
    src: url('../fonts/customiconpack.eot?lchn8y#iefix') format('embedded-opentype'),
         url('../fonts/customiconpack.ttf?lchn8y') format('truetype'),
         url('../fonts/customiconpack.woff2?lchn8y') format('woff'),
         url('../fonts/customiconpack.woff?lchn8y') format('woff'),
         url('../fonts/customiconpack.svg?lchn8y#customiconpack') format('svg');
    font-weight: normal;
    font-style: normal;
}

Keep in mind that you can get the glyph unicode values of each icon in your icon pack using the IcoMoon software. These values can be helpful in assigning your icons via CSS, as in (assuming we're using the font-family declared in the example @font-face {...} above):

selector:after {
    font-family: 'customiconpackname';
    content: '\e953';
    }

You can also get the glyph unicode value e953 if you open the font-pack-generated svg file in a text editor. E.g.:

<glyph unicode="&#xe953;" glyph-name="eye" ... />

jquery select element by xpath

If you are debugging or similar - In chrome developer tools, you can simply use

$x('/html/.//div[@id="text"]')

Get environment value in controller

In Controller

$hostname = $_ENV['IMAP_HOSTNAME_TEST']; (or) $hostname = env('IMAP_HOSTNAME_TEST');

In blade.view

{{$_ENV['IMAP_HOSTNAME_TEST']}}

PowerShell script to check the status of a URL

I recently set up a script that does this.

As David Brabant pointed out, you can use the System.Net.WebRequest class to do an HTTP request.

To check whether it is operational, you should use the following example code:

# First we create the request.
$HTTP_Request = [System.Net.WebRequest]::Create('http://google.com')

# We then get a response from the site.
$HTTP_Response = $HTTP_Request.GetResponse()

# We then get the HTTP code as an integer.
$HTTP_Status = [int]$HTTP_Response.StatusCode

If ($HTTP_Status -eq 200) {
    Write-Host "Site is OK!"
}
Else {
    Write-Host "The Site may be down, please check!"
}

# Finally, we clean up the http request by closing it.
If ($HTTP_Response -eq $null) { } 
Else { $HTTP_Response.Close() }

What is the difference between resource and endpoint?

The terms resource and endpoint are often used synonymously. But in fact they do not mean the same thing.

The term endpoint is focused on the URL that is used to make a request.
The term resource is focused on the data set that is returned by a request.

Now, the same resource can often be accessed by multiple different endpoints.
Also the same endpoint can return different resources, depending on a query string.

Let us see some examples:

Different endpoints accessing the same resource

Have a look at the following examples of different endpoints:

/api/companies/5/employees/3
/api/v2/companies/5/employees/3
/api/employees/3

They obviously could all access the very same resource in a given API.

Also an existing API could be changed completely. This could lead to new endpoints that would access the same old resources using totally new and different URLs:

/api/employees/3
/new_api/staff/3

One endpoint accessing different resources

If your endpoint returns a collection, you could implement searching/filtering/sorting using query strings. As a result the following URLs all use the same endpoint (/api/companies), but they can return different resources (or resource collections, which by definition are resources in themselves):

/api/companies
/api/companies?sort=name_asc
/api/companies?location=germany
/api/companies?search=siemens

How to check if a file exists from a url

Hi according to our test between 2 different servers the results are as follows:

using curl for checking 10 .png files (each about 5 mb) was on average 5.7 secs. using header check for the same thing took average of 7.8 seconds!

So in our test curl was much faster if you have to check larger files!

our curl function is:

function remote_file_exists($url){
    $ch = curl_init($url);
    curl_setopt($ch, CURLOPT_NOBODY, true);
    curl_exec($ch);
    $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
    curl_close($ch);
    if( $httpCode == 200 ){return true;}
    return false;
}

here is our header check sample:

function UR_exists($url){
   $headers=get_headers($url);
   return stripos($headers[0],"200 OK")?true:false;
}

Concatenating two one-dimensional NumPy arrays

Some more facts from the numpy docs :

With syntax as numpy.concatenate((a1, a2, ...), axis=0, out=None)

axis = 0 for row-wise concatenation axis = 1 for column-wise concatenation

>>> a = np.array([[1, 2], [3, 4]])
>>> b = np.array([[5, 6]])

# Appending below last row
>>> np.concatenate((a, b), axis=0)
array([[1, 2],
       [3, 4],
       [5, 6]])

# Appending after last column
>>> np.concatenate((a, b.T), axis=1)    # Notice the transpose
array([[1, 2, 5],
       [3, 4, 6]])

# Flattening the final array
>>> np.concatenate((a, b), axis=None)
array([1, 2, 3, 4, 5, 6])

I hope it helps !

Is an entity body allowed for an HTTP DELETE request?

Just a heads up, if you supply a body in your DELETE request and are using a google cloud HTTPS load balancer, it will reject your request with a 400 error. I was banging my head against a wall and came to found out that Google, for whatever reason, thinks a DELETE request with a body is a malformed request.

How do you compare two version Strings in Java?

Tokenize the strings with the dot as delimiter and then compare the integer translation side by side, beginning from the left.

Force LF eol in git repo and working copy

To force LF line endings for all text files, you can create .gitattributes file in top-level of your repository with the following lines (change as desired):

# Ensure all C and PHP files use LF.
*.c         eol=lf
*.php       eol=lf

which ensures that all files that Git considers to be text files have normalized (LF) line endings in the repository (normally core.eol configuration controls which one do you have by default).

Based on the new attribute settings, any text files containing CRLFs should be normalized by Git. If this won't happen automatically, you can refresh a repository manually after changing line endings, so you can re-scan and commit the working directory by the following steps (given clean working directory):

$ echo "* text=auto" >> .gitattributes
$ rm .git/index     # Remove the index to force Git to
$ git reset         # re-scan the working directory
$ git status        # Show files that will be normalized
$ git add -u
$ git add .gitattributes
$ git commit -m "Introduce end-of-line normalization"

or as per GitHub docs:

git add . -u
git commit -m "Saving files before refreshing line endings"
git rm --cached -r . # Remove every file from Git's index.
git reset --hard # Rewrite the Git index to pick up all the new line endings.
git add . # Add all your changed files back, and prepare them for a commit.
git commit -m "Normalize all the line endings" # Commit the changes to your repository.

See also: @Charles Bailey post.

In addition, if you would like to exclude any files to not being treated as a text, unset their text attribute, e.g.

manual.pdf      -text

Or mark it explicitly as binary:

# Denote all files that are truly binary and should not be modified.
*.png binary
*.jpg binary

To see some more advanced git normalization file, check .gitattributes at Drupal core:

# Drupal git normalization
# @see https://www.kernel.org/pub/software/scm/git/docs/gitattributes.html
# @see https://www.drupal.org/node/1542048

# Normally these settings would be done with macro attributes for improved
# readability and easier maintenance. However macros can only be defined at the
# repository root directory. Drupal avoids making any assumptions about where it
# is installed.

# Define text file attributes.
# - Treat them as text.
# - Ensure no CRLF line-endings, neither on checkout nor on checkin.
# - Detect whitespace errors.
#   - Exposed by default in `git diff --color` on the CLI.
#   - Validate with `git diff --check`.
#   - Deny applying with `git apply --whitespace=error-all`.
#   - Fix automatically with `git apply --whitespace=fix`.

*.config  text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.css     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.dist    text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.engine  text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.html    text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=html
*.inc     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.install text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.js      text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.json    text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.lock    text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.map     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.md      text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.module  text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.php     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.po      text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.profile text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.script  text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.sh      text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.sql     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.svg     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.theme   text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.twig    text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.txt     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.xml     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.yml     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2

# Define binary file attributes.
# - Do not treat them as text.
# - Include binary diff in patches instead of "binary files differ."
*.eot     -text diff
*.exe     -text diff
*.gif     -text diff
*.gz      -text diff
*.ico     -text diff
*.jpeg    -text diff
*.jpg     -text diff
*.otf     -text diff
*.phar    -text diff
*.png     -text diff
*.svgz    -text diff
*.ttf     -text diff
*.woff    -text diff
*.woff2   -text diff

See also:

DIV table colspan: how?

In order to get "colspan" functionality out of div based tabular layout, you need to abandon the use of the display:table | display:row styles. Especially in cases where each data item spans more than one row and you need different sized "cells" in each row.

How to check if array element exists or not in javascript?

Simple way to check item exist or not

Array.prototype.contains = function(obj) {
    var i = this.length;
    while (i--)
       if (this[i] == obj)
       return true;
    return false;
}

var myArray= ["Banana", "Orange", "Apple", "Mango"];

myArray.contains("Apple")

How to serve up images in Angular2?

I am using the Asp.Net Core angular template project with an Angular 4 front end and webpack. I had to use '/dist/assets/images/' in front of the image name, and store the image in the assets/images directory in the dist directory. eg:

 <img  class="img-responsive" src="/dist/assets/images/UnitBadge.jpg">

How to get a List<string> collection of values from app.config in WPF?

You can create your own custom config section in the app.config file. There are quite a few tutorials around to get you started. Ultimately, you could have something like this:

<configSections>
    <section name="backupDirectories" type="TestReadMultipler2343.BackupDirectoriesSection, TestReadMultipler2343" />
  </configSections>

<backupDirectories>
   <directory location="C:\test1" />
   <directory location="C:\test2" />
   <directory location="C:\test3" />
</backupDirectories>

To complement Richard's answer, this is the C# you could use with his sample configuration:

using System.Collections.Generic;
using System.Configuration;
using System.Xml;

namespace TestReadMultipler2343
{
    public class BackupDirectoriesSection : IConfigurationSectionHandler
    {
        public object Create(object parent, object configContext, XmlNode section)
        {
            List<directory> myConfigObject = new List<directory>();

            foreach (XmlNode childNode in section.ChildNodes)
            {
                foreach (XmlAttribute attrib in childNode.Attributes)
                {
                    myConfigObject.Add(new directory() { location = attrib.Value });
                }
            }
            return myConfigObject;
        }
    }

    public class directory
    {
        public string location { get; set; }
    }
}

Then you can access the backupDirectories configuration section as follows:

List<directory> dirs = ConfigurationManager.GetSection("backupDirectories") as List<directory>;

Tracking the script execution time in PHP

If all you need is the wall-clock time, rather than the CPU execution time, then it is simple to calculate:

//place this before any script you want to calculate time
$time_start = microtime(true); 

//sample script
for($i=0; $i<1000; $i++){
 //do anything
}

$time_end = microtime(true);

//dividing with 60 will give the execution time in minutes otherwise seconds
$execution_time = ($time_end - $time_start)/60;

//execution time of the script
echo '<b>Total Execution Time:</b> '.$execution_time.' Mins';
// if you get weird results, use number_format((float) $execution_time, 10) 

Note that this will include time that PHP is sat waiting for external resources such as disks or databases, which is not used for max_execution_time.

Code coverage with Mocha

Blanket.js works perfect too.

npm install --save-dev blanket

in front of your test/tests.js

require('blanket')({
    pattern: function (filename) {
        return !/node_modules/.test(filename);
    }
});

run mocha -R html-cov > coverage.html

How can I delay a :hover effect in CSS?

For a more aesthetic appearance :) can be:

left:-9999em; 
top:-9999em; 

position for .sNv2 .nav UL can be replaced by z-index:-1 and z-index:1 for .sNv2 .nav LI:Hover UL

JavaScript unit test tools for TDD

YUI has a testing framework as well. This video from Yahoo! Theater is a nice introduction, although there are a lot of basics about TDD up front.

This framework is generic and can be run against any JavaScript or JS library.

How to strip all non-alphabetic characters from string in SQL Server?

this way didn't work for me as i was trying to keep the Arabic letters i tried to replace the regular expression but also it didn't work. i wrote another method to work on ASCII level as it was my only choice and it worked.

 Create function [dbo].[RemoveNonAlphaCharacters] (@s varchar(4000)) returns varchar(4000)
   with schemabinding
begin
   if @s is null
      return null
   declare @s2 varchar(4000)
   set @s2 = ''
   declare @l int
   set @l = len(@s)
   declare @p int
   set @p = 1
   while @p <= @l begin
      declare @c int
      set @c = ascii(substring(@s, @p, 1))
      if @c between 48 and 57 or @c between 65 and 90 or @c between 97 and 122 or @c between 165 and 253 or @c between 32 and 33
         set @s2 = @s2 + char(@c)
      set @p = @p + 1
      end
   if len(@s2) = 0
      return null
   return @s2
   end

GO

Creating Accordion Table with Bootstrap

In the accepted answer you get annoying spacing between the visible rows when the expandable row is hidden. You can get rid of that by adding this to css:

.collapse-row.collapsed + tr {
     display: none;
}

'+' is adjacent sibling selector, so if you want your expandable row to be the next row, this selects the next tr following tr named collapse-row.

Here is updated fiddle: http://jsfiddle.net/Nb7wy/2372/

jQuery.each - Getting li elements inside an ul

$(function() {
    $('.phrase .items').each(function(i, items_list){
        var myText = "";

        $(items_list).find('li').each(function(j, li){
            alert(li.text());
        })

        alert(myText);

    });
};

How do I select child elements of any depth using XPath?

If you are using the XmlDocument and XmlNode.

Say:

XmlNode f = root.SelectSingleNode("//form[@id='myform']");

Use:

XmlNode s = f.SelectSingleNode(".//input[@type='submit']");

It depends on the tool that you use. But .// will select any child, any depth from a reference node.

Programmatically register a broadcast receiver

One important point that people forget to mention is the life time of the Broadcast Receiver. The difference of programmatically registering it from registering in AndroidManifest.xml is that. In the manifest file, it doesn't depend on application life time. While when programmatically registering it it does depend on the application life time. This means that if you register in AndroidManifest.xml, you can catch the broadcasted intents even when your application is not running.

Edit: The mentioned note is no longer true as of Android 3.1, the Android system excludes all receiver from receiving intents by default if the corresponding application has never been started by the user or if the user explicitly stopped the application via the Android menu (in Manage ? Application). https://developer.android.com/about/versions/android-3.1.html

This is an additional security feature as the user can be sure that only the applications he started will receive broadcast intents.

So it can be understood as receivers programmatically registered in Application's onCreate() would have same effect with ones declared in AndroidManifest.xml from Android 3.1 above.

Choose File Dialog

Was looking for a file/folder browser myself recently and decided to make a new explorer activity (Android library): https://github.com/vaal12/AndroidFileBrowser

Matching Test application https://github.com/vaal12/FileBrowserTestApplication- is a sample how to use.

Allows picking directories and files from phone file structure.

Python: SyntaxError: keyword can't be an expression

I guess many of us who came to this page have a problem with Scikit Learn, one way to solve it is to create a dictionary with parameters and pass it to the model:

params = {'C': 1e9, 'gamma': 1e-07}
cls = SVC(**params)    

How to check if an object is a list or tuple (but not string)?

This is not intended to directly answer the OP, but I wanted to share some related ideas.

I was very interested in @steveha answer above, which seemed to give an example where duck typing seems to break. On second thought, however, his example suggests that duck typing is hard to conform to, but it does not suggest that str deserves any special handling.

After all, a non-str type (e.g., a user-defined type that maintains some complicated recursive structures) may cause @steveha srepr function to cause an infinite recursion. While this is admittedly rather unlikely, we can't ignore this possibility. Therefore, rather than special-casing str in srepr, we should clarify what we want srepr to do when an infinite recursion results.

It may seem that one reasonable approach is to simply break the recursion in srepr the moment list(arg) == [arg]. This would, in fact, completely solve the problem with str, without any isinstance.

However, a really complicated recursive structure may cause an infinite loop where list(arg) == [arg] never happens. Therefore, while the above check is useful, it's not sufficient. We need something like a hard limit on the recursion depth.

My point is that if you plan to handle arbitrary argument types, handling str via duck typing is far, far easier than handling the more general types you may (theoretically) encounter. So if you feel the need to exclude str instances, you should instead demand that the argument is an instance of one of the few types that you explicitly specify.

Javascript onHover event

If you use the JQuery library you can use the .hover() event which merges the mouseover and mouseout event and helps you with the timing and child elements:

$(this).hover(function(){},function(){});

The first function is the start of the hover and the next is the end. Read more at: http://docs.jquery.com/Events/hover

Change UITextField and UITextView Cursor / Caret Color

Durgesh's approach does work.

I also used such KVC solutions many times. Despite it seems to be undocumented, but it works. Frankly, you don't use any private methods here - only Key-Value Coding which is legal.

P.S. Yesterday my new app appeared at AppStore without any problems with this approach. And it is not the first case when I use KVC in changing some read-only properties (like navigatonBar) or private ivars.

What are .dex files in Android?

dex file is a file that is executed on the Dalvik VM.

Dalvik VM includes several features for performance optimization, verification, and monitoring, one of which is Dalvik Executable (DEX).

Java source code is compiled by the Java compiler into .class files. Then the dx (dexer) tool, part of the Android SDK processes the .class files into a file format called DEX that contains Dalvik byte code. The dx tool eliminates all the redundant information that is present in the classes. In DEX all the classes of the application are packed into one file. The following table provides comparison between code sizes for JVM jar files and the files processed by the dex tool.

The table compares code sizes for system libraries, web browser applications, and a general purpose application (alarm clock app). In all cases dex tool reduced size of the code by more than 50%.

enter image description here

In standard Java environments each class in Java code results in one .class file. That means, if the Java source code file has one public class and two anonymous classes, let’s say for event handling, then the java compiler will create total three .class files.

The compilation step is same on the Android platform, thus resulting in multiple .class files. But after .class files are generated, the “dx” tool is used to convert all .class files into a single .dex, or Dalvik Executable, file. It is the .dex file that is executed on the Dalvik VM. The .dex file has been optimized for memory usage and the design is primarily driven by sharing of data.

How to get an absolute file path in Python

Today you can also use the unipath package which was based on path.py: http://sluggo.scrapping.cc/python/unipath/

>>> from unipath import Path
>>> absolute_path = Path('mydir/myfile.txt').absolute()
Path('C:\\example\\cwd\\mydir\\myfile.txt')
>>> str(absolute_path)
C:\\example\\cwd\\mydir\\myfile.txt
>>>

I would recommend using this package as it offers a clean interface to common os.path utilities.

HttpClient - A task was cancelled?

Another possibility is that the result is not awaited on the client side. This can happen if any one method on the call stack does not use the await keyword to wait for the call to be completed.

How can I create tests in Android Studio?

I would suggest to use gradle.build file.

  1. Add a src/androidTest/java directory for the tests (Like Chris starts to explain)

  2. Open gradle.build file and specify there:

    android {
    
        compileSdkVersion rootProject.compileSdkVersion
        buildToolsVersion rootProject.buildToolsVersion
    
        sourceSets {
    
            androidTest {
                java.srcDirs = ['androidTest/java']
            }
        }
    }
    
  3. Press "Sync Project with Gradle file" (at the top panel). You should see now a folder "java" (inside "androidTest") is a green color.

  4. Now You are able to create there any test files and execute they.

C++ multiline string literal

Option 1. Using boost library, you can declare the string as below

const boost::string_view helpText = "This is very long help text.\n"
      "Also more text is here\n"
      "And here\n"

// Pass help text here
setHelpText(helpText);

Option 2. If boost is not available in your project, you can use std::string_view() in modern C++.

Send JSON via POST in C# and Receive the JSON returned?

You can also use the PostAsJsonAsync() method available in HttpClient()

_x000D_
_x000D_
   var requestObj= JsonConvert.SerializeObject(obj);_x000D_
   HttpResponseMessage response = await    client.PostAsJsonAsync($"endpoint",requestObj).ConfigureAwait(false);
_x000D_
_x000D_
_x000D_

ansible: lineinfile for several lines?

To add multiple lines you can use blockfile:

- name: Add mappings to /etc/hosts
  blockinfile:
    path: /etc/hosts
    block: |
      '10.10.10.10  server.example.com'
      '10.10.10.11  server1.example.com'

to Add one line you can use lininfile:

- name: server.example.com in /etc/hosts
  lineinfile:
    path: /etc/hosts
    line: '192.0.2.42 server.example.com server'
    state: present

What is the result of % in Python?

The modulus is a mathematical operation, sometimes described as "clock arithmetic." I find that describing it as simply a remainder is misleading and confusing because it masks the real reason it is used so much in computer science. It really is used to wrap around cycles.

Think of a clock: Suppose you look at a clock in "military" time, where the range of times goes from 0:00 - 23.59. Now if you wanted something to happen every day at midnight, you would want the current time mod 24 to be zero:

if (hour % 24 == 0):

You can think of all hours in history wrapping around a circle of 24 hours over and over and the current hour of the day is that infinitely long number mod 24. It is a much more profound concept than just a remainder, it is a mathematical way to deal with cycles and it is very important in computer science. It is also used to wrap around arrays, allowing you to increase the index and use the modulus to wrap back to the beginning after you reach the end of the array.

There isn't anything to compare. Nothing to compare, branches are entirely different commit histories

I wanted to copy commit history of "master" branch & overwrite the commit history of "main" branch .
The steps are:-

  1. git checkout master
  2. git branch main master -f
  3. git checkout main
  4. git push

To delete master branch:-

a. Locally:-

  1. git checkout main
  2. git branch -d master

b. Globally:-

  1. git push origin --delete master

Do Upvote it!

How to set standard encoding in Visual Studio

I work with Windows7.

Control Panel - Region and Language - Administrative - Language for non-Unicode programs.

After I set "Change system locale" to English(United States). My default encoding of vs2010 change to Windows-1252. It was gb2312 before.

I created a new .cpp file for a C++ project, after checking in the new file to TFS the encoding show Windows-1252 from the properties page of the file.

How to validate an Email in PHP?

I always use this:

function validEmail($email){
    // First, we check that there's one @ symbol, and that the lengths are right
    if (!preg_match("/^[^@]{1,64}@[^@]{1,255}$/", $email)) {
        // Email invalid because wrong number of characters in one section, or wrong number of @ symbols.
        return false;
    }
    // Split it into sections to make life easier
    $email_array = explode("@", $email);
    $local_array = explode(".", $email_array[0]);
    for ($i = 0; $i < sizeof($local_array); $i++) {
        if (!preg_match("/^(([A-Za-z0-9!#$%&'*+\/=?^_`{|}~-][A-Za-z0-9!#$%&'*+\/=?^_`{|}~\.-]{0,63})|(\"[^(\\|\")]{0,62}\"))$/", $local_array[$i])) {
            return false;
        }
    }
    if (!preg_match("/^\[?[0-9\.]+\]?$/", $email_array[1])) { // Check if domain is IP. If not, it should be valid domain name
        $domain_array = explode(".", $email_array[1]);
        if (sizeof($domain_array) < 2) {
            return false; // Not enough parts to domain
        }
        for ($i = 0; $i < sizeof($domain_array); $i++) {
            if (!preg_match("/^(([A-Za-z0-9][A-Za-z0-9-]{0,61}[A-Za-z0-9])|([A-Za-z0-9]+))$/", $domain_array[$i])) {
                return false;
            }
        }
    }

    return true;
}

Problems with local variable scope. How to solve it?

not Error:

JSONObject json1 = getJsonX();

Error:

JSONObject json2 = null;
if(x == y)
   json2 = getJSONX();

Error: Local variable statement defined in an enclosing scope must be final or effectively final.

But you can write:

JSONObject json2 = (x == y) ? json2 = getJSONX() : null;

Run a PostgreSQL .sql file using command line arguments

export PGPASSWORD=<password>
psql -h <host> -d <database> -U <user_name> -p <port> -a -w -f <file>.sql

Copy a git repo without history

Deleting the .git folder is probably the easiest path since you don't want/need the history (as Stephan said).

So you can create a new repo from your latest commit: (How to clone seed/kick-start project without the whole history?)

git clone <git_url>

then delete .git, and afterwards run

git init

Or if you want to reuse your current repo: Make the current commit the only (initial) commit in a Git repository?

Follow the above steps then:

git add .
git commit -m "Initial commit"

Push to your repo.

git remote add origin <github-uri>
git push -u --force origin master

How to access the GET parameters after "?" in Express?

Query string and parameters are different.

You need to use both in single routing url

Please check below example may be useful for you.

app.get('/sample/:id', function(req, res) {

 var id = req.params.id; //or use req.param('id')

  ................

});

Get the link to pass your second segment is your id example: http://localhost:port/sample/123

If you facing problem please use Passing variables as query string using '?' operator

  app.get('/sample', function(req, res) {

     var id = req.query.id; 

      ................

    });

Get link your like this example: http://localhost:port/sample?id=123

Both in a single example

app.get('/sample/:id', function(req, res) {

 var id = req.params.id; //or use req.param('id')
 var id2 = req.query.id; 
  ................

});

Get link example: http://localhost:port/sample/123?id=123

Show git diff on file in staging area

You can show changes that have been staged with the --cached flag:

$ git diff --cached

In more recent versions of git, you can also use the --staged flag (--staged is a synonym for --cached):

$ git diff --staged

How to convert std::string to LPCWSTR in C++ (Unicode)

If you are in an ATL/MFC environment, You can use the ATL conversion macro:

#include <atlbase.h>
#include <atlconv.h>

. . .

string myStr("My string");
CA2W unicodeStr(myStr);

You can then use unicodeStr as an LPCWSTR. The memory for the unicode string is created on the stack and released then the destructor for unicodeStr executes.

overlay a smaller image on a larger image python OpenCv

A simple function that blits an image front onto an image back and returns the result. It works with both 3 and 4-channel images and deals with the alpha channel. Overlaps are handled as well.

The output image has the same size as back, but always 4 channels.
The output alpha channel is given by (u+v)/(1+uv) where u,v are the alpha channels of the front and back image and -1 <= u,v <= 1. Where there is no overlap with front, the alpha value from back is taken.

import cv2

def merge_image(back, front, x,y):
    # convert to rgba
    if back.shape[2] == 3:
        back = cv2.cvtColor(back, cv2.COLOR_BGR2BGRA)
    if front.shape[2] == 3:
        front = cv2.cvtColor(front, cv2.COLOR_BGR2BGRA)

    # crop the overlay from both images
    bh,bw = back.shape[:2]
    fh,fw = front.shape[:2]
    x1, x2 = max(x, 0), min(x+fw, bw)
    y1, y2 = max(y, 0), min(y+fh, bh)
    front_cropped = front[y1-y:y2-y, x1-x:x2-x]
    back_cropped = back[y1:y2, x1:x2]

    alpha_front = front_cropped[:,:,3:4] / 255
    alpha_back = back_cropped[:,:,3:4] / 255
    
    # replace an area in result with overlay
    result = back.copy()
    print(f'af: {alpha_front.shape}\nab: {alpha_back.shape}\nfront_cropped: {front_cropped.shape}\nback_cropped: {back_cropped.shape}')
    result[y1:y2, x1:x2, :3] = alpha_front * front_cropped[:,:,:3] + alpha_back * back_cropped[:,:,:3]
    result[y1:y2, x1:x2, 3:4] = (alpha_front + alpha_back) / (1 + alpha_front*alpha_back) * 255

    return result

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

If you're using C# ASP.NET MVC's default template you may find that site.css overrides some of Bootstraps styles. If you want to use Bootstrap, as I did, having M$ override this (without your knowledge) can be a source of great frustration! Feel free to remove any of the unwanted styles...

/* Set width on the form input elements since they're 100% wide by default */
input,
select,
textarea {
    max-width: 280px;
}

Spring Boot - Cannot determine embedded database driver class for database type NONE

The same to @Anas. I can run it in Eclipse, but when i use "java -jar ..." run it, it giving me this error. Then i find my java build path is wrong, it missing the folder “src/main/resources”, so, the application can't find application.properties. When i add the “src/main/resources” folder in java build path, it worked.

And, you need add "@PropertySource({"application.properties"})" in your Application class.

Screenshot-1

Screenshot-2

Why do Twitter Bootstrap tables always have 100% width?

I've tried to add style="width: auto !important" and works great for me!

Repair all tables in one go

There is no default command to do that, but you may create a procedure to do the job. It will iterate through rows of information_schema and call REPAIR TABLE 'tablename'; for every row. CHECK TABLE is not yet supported for prepared statements. Here's the example (replace MYDATABASE with your database name):

CREATE DEFINER = 'root'@'localhost'
PROCEDURE MYDATABASE.repair_all()
BEGIN
  DECLARE endloop INT DEFAULT 0;
  DECLARE tableName char(100);
  DECLARE rCursor CURSOR FOR SELECT `TABLE_NAME` FROM `information_schema`.`TABLES` WHERE `TABLE_SCHEMA`=DATABASE();
  DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET endloop=1;

  OPEN rCursor;
  FETCH rCursor INTO tableName;

  WHILE endloop = 0 DO
    SET @sql = CONCAT("REPAIR TABLE `", tableName, "`");
    PREPARE statement FROM @sql;
    EXECUTE statement;

    FETCH rCursor INTO tableName;
  END WHILE;

  CLOSE rCursor;
END

Convert DateTime to long and also the other way around

Since you're using ToFileTime, you'll want to use FromFileTime to go the other way. But note:

Ordinarily, the FromFileTime method restores a DateTime value that was saved by the ToFileTime method. However, the two values may differ under the following conditions:

If the serialization and deserialization of the DateTime value occur in different time zones. For example, if a DateTime value with a time of 12:30 P.M. in the U.S. Eastern Time zone is serialized, and then deserialized in the U.S. Pacific Time zone, the original value of 12:30 P.M. is adjusted to 9:30 A.M. to reflect the difference between the two time zones.

If the DateTime value that is serialized represents an invalid time in the local time zone. In this case, the ToFileTime method adjusts the restored DateTime value so that it represents a valid time in the local time zone.

If you don't care which long representation of a DateTime is stored, you can use Ticks as others have suggested (Ticks is probably preferable, depending on your requirements, since the value returned by ToFileTime seems to be in the context of the Windows filesystem API).

Spark Kill Running Application

First use:

yarn application -list

Note down the application id Then to kill use:

yarn application -kill application_id

super() in Java

I would like to share with codes whatever I understood.

The super keyword in java is a reference variable that is used to refer parent class objects. It is majorly used in the following contexts:-

1. Use of super with variables:

class Vehicle 
{ 
    int maxSpeed = 120; 
} 

/* sub class Car extending vehicle */
class Car extends Vehicle 
{ 
    int maxSpeed = 180; 

    void display() 
    { 
        /* print maxSpeed of base class (vehicle) */
        System.out.println("Maximum Speed: " + super.maxSpeed); 
    } 
} 

/* Driver program to test */
class Test 
{ 
    public static void main(String[] args) 
    { 
        Car small = new Car(); 
        small.display(); 
    } 
} 

Output:-

Maximum Speed: 120
  1. Use of super with methods:
/* Base class Person */
class Person 
{ 
    void message() 
    { 
        System.out.println("This is person class"); 
    } 
} 

/* Subclass Student */
class Student extends Person 
{ 
    void message() 
    { 
        System.out.println("This is student class"); 
    } 

    // Note that display() is only in Student class 
    void display() 
    { 
        // will invoke or call current class message() method 
        message(); 

        // will invoke or call parent class message() method 
        super.message(); 
    } 
} 

/* Driver program to test */
class Test 
{ 
    public static void main(String args[]) 
    { 
        Student s = new Student(); 

        // calling display() of Student 
        s.display(); 
    } 
}

Output:-

This is student class
This is person class

3. Use of super with constructors:

class Person 
{ 
    Person() 
    { 
        System.out.println("Person class Constructor"); 
    } 
} 

/* subclass Student extending the Person class */
class Student extends Person 
{ 
    Student() 
    { 
        // invoke or call parent class constructor 
        super(); 

        System.out.println("Student class Constructor"); 
    } 
} 

/* Driver program to test*/
class Test 
{ 
    public static void main(String[] args) 
    { 
        Student s = new Student(); 
    } 
} 

Output:-

Person class Constructor
Student class Constructor

Can an Android NFC phone act as an NFC tag?

In the google io session about NFC, qa section. There was such a question:

card emulation? No API support for card emulation No consistent user experience when doing card emulation and no compelling story

How do I download a package from apt-get without installing it?

Try

apt-get -d install <packages>

It is documented in man apt-get.

Just for clarification; the downloaded packages are located in the apt package cache at

/var/cache/apt/archives

Error inflating when extending a class

in my case I added such cyclic resource:

<drawable name="above_shadow">@drawable/above_shadow</drawable>

then changed to

<drawable name="some_name">@drawable/other_name</drawable>

and it worked

How to establish ssh key pair when "Host key verification failed"

First you should remove existing key. SSH keys in most of Linux-based OS will be saved this file "/root/.ssh/known_hosts", so in order to remove the key related to host the following command will be used:

ssh-keygen -f "/root/.ssh/known_hosts" -R [Hostname]

Regards K1

mongodb: insert if not exists

1. Use Update.

Drawing from Van Nguyen's answer above, use update instead of save. This gives you access to the upsert option.

NOTE: This method overrides the entire document when found (From the docs)

var conditions = { name: 'borne' }   , update = { $inc: { visits: 1 }} , options = { multi: true };

Model.update(conditions, update, options, callback);

function callback (err, numAffected) {   // numAffected is the number of updated documents })

1.a. Use $set

If you want to update a selection of the document, but not the whole thing, you can use the $set method with update. (again, From the docs)... So, if you want to set...

var query = { name: 'borne' };  Model.update(query, ***{ name: 'jason borne' }***, options, callback)

Send it as...

Model.update(query, ***{ $set: { name: 'jason borne' }}***, options, callback)

This helps prevent accidentally overwriting all of your document(s) with { name: 'jason borne' }.

Difference between adjustResize and adjustPan in android?

adjustResize = resize the page content

adjustPan = move page content without resizing page content

Pandas "Can only compare identically-labeled DataFrame objects" error

When you compare two DataFrames, you must ensure that the number of records in the first DataFrame matches with the number of records in the second DataFrame. In our example, each of the two DataFrames had 4 records, with 4 products and 4 prices.

If, for example, one of the DataFrames had 5 products, while the other DataFrame had 4 products, and you tried to run the comparison, you would get the following error:

ValueError: Can only compare identically-labeled Series objects

this should work

import pandas as pd
import numpy as np

firstProductSet = {'Product1': ['Computer','Phone','Printer','Desk'],
                   'Price1': [1200,800,200,350]
                   }
df1 = pd.DataFrame(firstProductSet,columns= ['Product1', 'Price1'])


secondProductSet = {'Product2': ['Computer','Phone','Printer','Desk'],
                    'Price2': [900,800,300,350]
                    }
df2 = pd.DataFrame(secondProductSet,columns= ['Product2', 'Price2'])


df1['Price2'] = df2['Price2'] #add the Price2 column from df2 to df1

df1['pricesMatch?'] = np.where(df1['Price1'] == df2['Price2'], 'True', 'False')  #create new column in df1 to check if prices match
df1['priceDiff?'] = np.where(df1['Price1'] == df2['Price2'], 0, df1['Price1'] - df2['Price2']) #create new column in df1 for price diff 
print (df1)

example from https://datatofish.com/compare-values-dataframes/

Fatal error: Out of memory, but I do have plenty of memory (PHP)

This is a known bug in PHP v 5.2 for Windows, it is present at least to version 5.2.3: https://bugs.php.net/bug.php?id=41615

None of the suggested fixes have helped for us, we're going to have to update PHP.

jQuery select by attribute using AND and OR operators

First find the condition that occurs in all situations, then filter the special conditions:

$('[myc="blue"]')
    .filter('[myid="1"],[myid="3"]');

How can I change the app display name build with Flutter?

For Android, change the app name from the Android folder. In the AndroidManifest.xml file, in folder android/app/src/main, let the android label refer to the name you prefer, for example,

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    <application
        `android:label="myappname"`
        // The rest of the code
    </application>
</manifest>

Xml Parsing in C#

First add an Enrty and Category class:

public class Entry {     public string Id { get; set; }     public string Title { get; set; }     public string Updated { get; set; }     public string Summary { get; set; }     public string GPoint { get; set; }     public string GElev { get; set; }     public List<string> Categories { get; set; } }  public class Category {     public string Label { get; set; }     public string Term { get; set; } } 

Then use LINQ to XML

XDocument xDoc = XDocument.Load("path");          List<Entry> entries = (from x in xDoc.Descendants("entry")             select new Entry()             {                 Id = (string) x.Element("id"),                 Title = (string)x.Element("title"),                 Updated = (string)x.Element("updated"),                 Summary = (string)x.Element("summary"),                 GPoint = (string)x.Element("georss:point"),                 GElev = (string)x.Element("georss:elev"),                 Categories = (from c in x.Elements("category")                                   select new Category                                   {                                       Label = (string)c.Attribute("label"),                                       Term = (string)c.Attribute("term")                                   }).ToList();             }).ToList(); 

What's wrong with overridable method calls in constructors?

If you call methods in your constructor that subclasses override, it means you are less likely to be referencing variables that don’t exist yet if you divide your initialization logically between the constructor and the method.

Have a look on this sample link http://www.javapractices.com/topic/TopicAction.do?Id=215

Python, TypeError: unhashable type: 'list'

The problem is that you can't use a list as the key in a dict, since dict keys need to be immutable. Use a tuple instead.

This is a list:

[x, y]

This is a tuple:

(x, y)

Note that in most cases, the ( and ) are optional, since , is what actually defines a tuple (as long as it's not surrounded by [] or {}, or used as a function argument).

You might find the section on tuples in the Python tutorial useful:

Though tuples may seem similar to lists, they are often used in different situations and for different purposes. Tuples are immutable, and usually contain an heterogeneous sequence of elements that are accessed via unpacking (see later in this section) or indexing (or even by attribute in the case of namedtuples). Lists are mutable, and their elements are usually homogeneous and are accessed by iterating over the list.

And in the section on dictionaries:

Unlike sequences, which are indexed by a range of numbers, dictionaries are indexed by keys, which can be any immutable type; strings and numbers can always be keys. Tuples can be used as keys if they contain only strings, numbers, or tuples; if a tuple contains any mutable object either directly or indirectly, it cannot be used as a key. You can’t use lists as keys, since lists can be modified in place using index assignments, slice assignments, or methods like append() and extend().


In case you're wondering what the error message means, it's complaining because there's no built-in hash function for lists (by design), and dictionaries are implemented as hash tables.

Left-pad printf with spaces

I use this function to indent my output (for example to print a tree structure). The indent is the number of spaces before the string.

void print_with_indent(int indent, char * string)
{
    printf("%*s%s", indent, "", string);
}

How do I get into a Docker container's shell?

If you are using Docker Compose then this will take you inside a Docker container.

docker-compose run container_name /bin/bash

Inside the container it will take you to WORKDIR defined in the Dockerfile. You can change your work directory by

WORKDIR directory_path # E.g  /usr/src -> container's path

How to request Location Permission at runtime

Google has created a library for easy Permissions management. Its called EasyPermissions

Here is a simple example on requesting Location permission using this library.

public class MainActivity extends AppCompatActivity {

    private final int REQUEST_LOCATION_PERMISSION = 1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        requestLocationPermission();
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        // Forward results to EasyPermissions
        EasyPermissions.onRequestPermissionsResult(requestCode, permissions, grantResults, this);
    }

    @AfterPermissionGranted(REQUEST_LOCATION_PERMISSION)
    public void requestLocationPermission() {
        String[] perms = {Manifest.permission.ACCESS_FINE_LOCATION};
        if(EasyPermissions.hasPermissions(this, perms)) {
            Toast.makeText(this, "Permission already granted", Toast.LENGTH_SHORT).show();
        }
        else {
            EasyPermissions.requestPermissions(this, "Please grant the location permission", REQUEST_LOCATION_PERMISSION, perms);
        }
    }
}

@AfterPermissionsGranted(REQUEST_CODE) is used to indicate the method that needs to be executed after a permission request with the request code REQUEST_CODE has been granted.

This above case, the method requestLocationPermission() method is called if the user grants the permission to access location services. So, that method acts as both a callback and a method to request the permissions.

You can implement separate callbacks for permission granted and permission denied as well. It is explained in the github page.

null vs empty string in Oracle

In oracle an empty varchar2 and null are treated the same, and your observations show that.

when you write:

select * from table where a = '';

its the same as writing

select * from table where a = null;

and not a is null

which will never equate to true, so never return a row. same on the insert, a NOT NULL means you cant insert a null or an empty string (which is treated as a null)

How to get the selected value from RadioButtonList?

Using your radio button's ID, try rb.SelectedValue.

How to create a Java cron job

If you are using unix, you need to write a shellscript to run you java batch first.

After that, in unix, you run this command "crontab -e" to edit crontab script. In order to configure crontab, please refer to this article http://www.thegeekstuff.com/2009/06/15-practical-crontab-examples/

Save your crontab setting. Then wait for the time to come, program will run automatically.

Using File.listFiles with FileNameExtensionFilter

With java lambdas (available since java 8) you can simply convert javax.swing.filechooser.FileFilter to java.io.FileFilter in one line.

javax.swing.filechooser.FileFilter swingFilter = new FileNameExtensionFilter("jpeg files", "jpeg");
java.io.FileFilter ioFilter = file -> swingFilter.accept(file);
new File("myDirectory").listFiles(ioFilter);

How to add/update child entities when updating a parent entity in EF

@Charles McIntosh really gave me the answer for my situation in that the passed in model was detached. For me what ultimately worked was saving the passed in model first... then continuing to add the children as I already was before:

public async Task<IHttpActionResult> GetUPSFreight(PartsExpressOrder order)
{
    db.Entry(order).State = EntityState.Modified;
    db.SaveChanges();
  ...
}

Open Url in default web browser

A simpler way which eliminates checking if the app can open the url.

  loadInBrowser = () => {
    Linking.openURL(this.state.url).catch(err => console.error("Couldn't load page", err));
  };

Calling it with a button.

<Button title="Open in Browser" onPress={this.loadInBrowser} />

DELETE ... FROM ... WHERE ... IN

You can achieve this using exists:

DELETE
  FROM table1
 WHERE exists(
           SELECT 1
             FROM table2
            WHERE table2.stn = table1.stn
              and table2.jaar = year(table1.datum)
       )

Add CSS3 transition expand/collapse

Here's a solution that doesn't use JS at all. It uses checkboxes instead.

You can hide the checkbox by adding this to your CSS:

.container input{
    display: none;
}

And then add some styling to make it look like a button.

Here's the source code that I modded.

How can I get form data with JavaScript/jQuery?

var formData = new FormData($('#form-id'));
params   = $('#form-id').serializeArray();

$.each(params, function(i, val) {
    formData.append(val.name, val.value);
});

How to set default values in Rails?

First of all you can't overload initialize(*args) as it's not called in all cases.

Your best option is to put your defaults into your migration:

add_column :accounts, :max_users, :integer, :default => 10

Second best is to place defaults into your model but this will only work with attributes that are initially nil. You may have trouble as I did with boolean columns:

def after_initialize
  if new_record?
    max_users ||= 10
  end
end

You need the new_record? so the defaults don't override values loaded from the datbase.

You need ||= to stop Rails from overriding parameters passed into the initialize method.

Select All as default value for Multivalue parameter

Using dataset with default values is one way, but you must use query for Available values and for Default Values, if values are hard coded in Available values tab, then you must define default values as expressions. Pictures should explain everything

Create Parameter (if not automaticly created)

Create Parameter

Define values - wrong way example

Define values - wrong way

Define values - correct way example

Define values - correct way

Set default values - you must define all default values reflecting available values to make "Select All" by default, if you won't define all only those defined will be selected by default.

Set default values

The Result

The result

One picture for Data type: Int

One picture for Data type Int

How to copy and paste worksheets between Excel workbooks?

when you paste into Word, the formating/formula of excel still exists. Simply click the clip board and select the option "keep text only."

Get the time of a datetime using T-SQL?

You can try the following code to get time as HH:MM format:

 SELECT CONVERT(VARCHAR(5),getdate(),108)

What is the difference between <section> and <div>?

<section> means that the content inside is grouped (i.e. relates to a single theme), and should appear as an entry in an outline of the page.

<div>, on the other hand, does not convey any meaning, aside from any found in its class, lang and title attributes.

So no: using a <div> does not define a section in HTML.

From the spec:

<section>

The <section> element represents a generic section of a document or application. A section, in this context, is a thematic grouping of content. Each section should be identified, typically by including a heading (h1-h6 element) as a child of the <section> element.

Examples of sections would be chapters, the various tabbed pages in a tabbed dialog box, or the numbered sections of a thesis. A Web site’s home page could be split into sections for an introduction, news items, and contact information.

...

The <section> element is not a generic container element. When an element is needed only for styling purposes or as a convenience for scripting, authors are encouraged to use the <div> element instead. A general rule is that the <section> element is appropriate only if the element’s contents would be listed explicitly in the document’s outline.

(https://www.w3.org/TR/html/sections.html#the-section-element)

<div>

The <div> element has no special meaning at all. It represents its children. It can be used with the class, lang, and title attributes to mark up semantics common to a group of consecutive elements.

Note: Authors are strongly encouraged to view the <div> element as an element of last resort, for when no other element is suitable. Use of more appropriate elements instead of the <div> element leads to better accessibility for readers and easier maintainability for authors.

(https://www.w3.org/TR/html/grouping-content.html#the-div-element)

Java String.split() Regex

    String str = "a + b - c * d / e < f > g >= h <= i == j";
    String reg = "\\s*[a-zA-Z]+";

    String[] res = str.split(reg);
    for (String out : res) {
        if (!"".equals(out)) {
            System.out.print(out);
        }
    }

Output : + - * / < > >= <= ==

Difference between pre-increment and post-increment in a loop?

One (++i) is preincrement, one (i++) is postincrement. The difference is in what value is immediately returned from the expression.

// Psuedocode
int i = 0;
print i++; // Prints 0
print i; // Prints 1
int j = 0;
print ++j; // Prints 1
print j; // Prints 1

Edit: Woops, entirely ignored the loop side of things. There's no actual difference in for loops when it's the 'step' portion (for(...; ...; )), but it can come into play in other cases.

How to replace spaces in file names using a bash script

you can use detox by Doug Harple

detox -r <folder>

Install Chrome extension form outside the Chrome Web Store

For Windows, you can also whitelist your extension through Windows policies. The full steps are details in this answer, but there are quicker steps:

  1. Create the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome\ExtensionInstallWhitelist.
  2. For each extension you want to whitelist, add a string value whose name should be a sequence number (starting at 1) and value is the extension ID.

For instance, in order to whitelist 2 extensions with ID aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa and bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb, create a string value with name 1 and value aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa, and a second value with name 2 and value bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb. This can be sum up by this registry file:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome]

[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome\ExtensionInstallWhitelist]
"1"="aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
"2"="bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"

EDIT: actually, Chromium docs also indicate how to do it for other OS.

CSV parsing in Java - working example..?

Basically you will need to read the file line by line.

Then you will need to split each line by the delimiter, say a comma (CSV stands for comma-separated values), with

String[] strArr=line.split(",");

This will turn it into an array of strings which you can then manipulate, for example with

String name=strArr[0];
int yearOfBirth = Integer.valueOf(strArr[1]);
int monthOfBirth = Integer.valueOf(strArr[2]);
int dayOfBirth = Integer.valueOf(strArr[3]);
GregorianCalendar dob=new GregorianCalendar(yearOfBirth, monthOfBirth, dayOfBirth);
Student student=new Student(name, dob); //lets pretend you are creating instances of Student

You will need to do this for every line so wrap this code into a while loop. (If you don't know the delimiter just open the file in a text editor.)

How to get the last value of an ArrayList

The size() method returns the number of elements in the ArrayList. The index values of the elements are 0 through (size()-1), so you would use myArrayList.get(myArrayList.size()-1) to retrieve the last element.

Create whole path automatically when writing to a new file

Use File.mkdirs():

File dir = new File("C:\\user\\Desktop\\dir1\\dir2");
dir.mkdirs();
File file = new File(dir, "filename.txt");
FileWriter newJsp = new FileWriter(file);

What is a serialVersionUID and why should I use it?

'serialVersionUID' is a 64 bit number used to uniquely identify a class during deserialization process. When you serialize an object, serialVersionUID of the class also written to the file. Whenever you deserialize this object, java run time extract this serialVersionUID value from the serialized data and compare the same value associate with the class. If both do not match, then 'java.io.InvalidClassException' will be thrown.

If a serializable class do not explicitly declare a serialVersionUID, then serialization runtime will calculate serialVersionUID value for that class based on various aspects of the class like fields, methods etc.,, You can refer this link for demo application.

Set cursor position on contentEditable <div>

In Firefox you might have the text of the div in a child node (o_div.childNodes[0])

var range = document.createRange();

range.setStart(o_div.childNodes[0],last_caret_pos);
range.setEnd(o_div.childNodes[0],last_caret_pos);
range.collapse(false);

var sel = window.getSelection(); 
sel.removeAllRanges();
sel.addRange(range);

Java - Convert int to Byte Array of 4 Bytes?

public static  byte[] my_int_to_bb_le(int myInteger){
    return ByteBuffer.allocate(4).order(ByteOrder.LITTLE_ENDIAN).putInt(myInteger).array();
}

public static int my_bb_to_int_le(byte [] byteBarray){
    return ByteBuffer.wrap(byteBarray).order(ByteOrder.LITTLE_ENDIAN).getInt();
}

public static  byte[] my_int_to_bb_be(int myInteger){
    return ByteBuffer.allocate(4).order(ByteOrder.BIG_ENDIAN).putInt(myInteger).array();
}

public static int my_bb_to_int_be(byte [] byteBarray){
    return ByteBuffer.wrap(byteBarray).order(ByteOrder.BIG_ENDIAN).getInt();
}

Which "href" value should I use for JavaScript links, "#" or "javascript:void(0)"?

So, when you are doing some JavaScript things with an <a /> tag and if you put href="#" as well, you can add return false at the end of the event (in case of inline event binding) like:

<a href="#" onclick="myJsFunc(); return false;">Run JavaScript Code</a>

Or you can change the href attribute with JavaScript like:

<a href="javascript://" onclick="myJsFunc();">Run JavaScript Code</a>

or

<a href="javascript:void(0)" onclick="myJsFunc();">Run JavaScript Code</a>

But semantically, all the above ways to achieve this are wrong (it works fine though). If any element is not created to navigate the page and that have some JavaScript things associated with it, then it should not be a <a> tag.

You can simply use a <button /> instead to do things or any other element like b, span or whatever fits there as per your need, because you are allowed to add events on all the elements.


So, there is one benefit to use <a href="#">. You get the cursor pointer by default on that element when you do a href="#". For that, I think you can use CSS for this like cursor:pointer; which solves this problem also.

And at the end, if you are binding the event from the JavaScript code itself, there you can do event.preventDefault() to achieve this if you are using <a> tag, but if you are not using a <a> tag for this, there you get an advantage, you don't need to do this.

So, if you see, it's better not to use a tag for this kind of stuff.

Get file size before uploading

Personally, I would say Web World's answer is the best today, given HTML standards. If you need to support IE < 10, you will need to use some form of ActiveX. I would avoid the recommendations that involve coding against Scripting.FileSystemObject, or instantiating ActiveX directly.

In this case, I have had success using 3rd party JS libraries such as plupload which can be configured to use HTML5 apis or Flash/Silverlight controls to backfill browsers that don't support those. Plupload has a client side API for checking file size that works in IE < 10.

gdb fails with "Unable to find Mach task port for process-id" error

I needed this command to make it work on El Capitan:

sudo security add-trust -d -r trustRoot -p basic -p codeSign -k /Library/Keychains/System.keychain ~/Desktop/gdb-cert.cer

Insert current date in datetime format mySQL

you can use CURRENT_TIMESTAMP, mysql function

What is an AssertionError? In which case should I throw it from my own code?

Of course the "You shall not instantiate an item of this class" statement has been violated, but if this is the logic behind that, then we should all throw AssertionErrors everywhere, and that is obviously not what happens.

The code isn't saying the user shouldn't call the zero-args constructor. The assertion is there to say that as far as the programmer is aware, he/she has made it impossible to call the zero-args constructor (in this case by making it private and not calling it from within Example's code). And so if a call occurs, that assertion has been violated, and so AssertionError is appropriate.

Why can't C# interfaces contain fields?

Why not just have a Year property, which is perfectly fine?

Interfaces don't contain fields because fields represent a specific implementation of data representation, and exposing them would break encapsulation. Thus having an interface with a field would effectively be coding to an implementation instead of an interface, which is a curious paradox for an interface to have!

For instance, part of your Year specification might require that it be invalid for ICar implementers to allow assignment to a Year which is later than the current year + 1 or before 1900. There's no way to say that if you had exposed Year fields -- far better to use properties instead to do the work here.

How can I detect Internet Explorer (IE) and Microsoft Edge using JavaScript?

Here is a javascript class that detects IE10, IE11 and Edge.
Navigator object is injected for testing purposes.

var DeviceHelper = function (_navigator) {
    this.navigator = _navigator || navigator;
};
DeviceHelper.prototype.isIE = function() {
    if(!this.navigator.userAgent) {
        return false;
    }

    var IE10 = Boolean(this.navigator.userAgent.match(/(MSIE)/i)),
        IE11 = Boolean(this.navigator.userAgent.match(/(Trident)/i));
    return IE10 || IE11;
};

DeviceHelper.prototype.isEdge = function() {
    return !!this.navigator.userAgent && this.navigator.userAgent.indexOf("Edge") > -1;
};

DeviceHelper.prototype.isMicrosoftBrowser = function() {
    return this.isEdge() || this.isIE();
};

How to fire a button click event from JavaScript in ASP.NET

var clickButton = document.getElementById("<%= btnClearSession.ClientID %>");
clickButton.click();

That solution works for me, but remember it wont work if your asp button has

Visible="False"

To hide button that should be triggered with that script you should hide it with <div hidden></div>

Error importing SQL dump into MySQL: Unknown database / Can't create database

It sounds like your database dump includes the information for creating the database. So don't give the MySQL command line a database name. It will create the new database and switch to it to do the import.

A server with the specified hostname could not be found

It might be DNS Pollution issue, at least for my case (in China).

If you're also in China or some places that has DNS Pollution issue, you might solve this by modifying the DNS (to 8.8.8.8 as an example) for your Mac as well.


I got this error inner my iPad App & this happens randomly, it's such boring. Keep trying is not a good solution for me, though it might works somehow. Finally, I just changed my Wi-Fi DNS and no more error now. Steps:

  1. Your device, Settings/Wi-Fi
  2. Choose connected Wi-Fi pot
  3. Press DHCP/DNS
  4. Set to 8.8.8.8

What does an exclamation mark mean in the Swift language?

If john were an optional var (declared thusly)

var john: Person?

then it would be possible for john to have no value (in ObjC parlance, nil value)

The exclamation point basically tells the compiler "I know this has a value, you don't need to test for it". If you didn't want to use it, you could conditionally test for it:

if let otherPerson = john {
    otherPerson.apartment = number73
}

The interior of this will only evaluate if john has a value.

In Javascript, how to conditionally add a member to an object?

You can add all your undefined values with no condition and then use JSON.stringify to remove them all :

const person = {
  name: undefined,
  age: 22,
  height: null
}

const cleaned = JSON.parse(JSON.stringify(person));

// Contents of cleaned:

// cleaned = {
//   age: 22,
//   height: null
// }

Set EditText cursor color

Wow I am real late to this party but it has had activity 17 days ago It would seam we need to consider posting what version of Android we are using for an answer so as of now this answer works with Android 2.1 and above Go to RES/VALUES/STYLES and add the lines of code below and your cursor will be black

    <style name="AppTheme" parent="Theme.AppCompat.NoActionBar">
    <!--<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">-->
    <!-- Customize your theme here. -->
    <item name="colorControlActivated">@color/color_Black</item>
    <!--Sets COLOR for the Cursor in EditText  -->
</style>

You will need a this line of code in your RES/COLOR folder

<color name="color_Black">#000000</color>

Why post this late ? It might be nice to consider some form of categories for the many headed monster Android has become!

How to replace a whole line with sed?

Like this:

sed 's/aaa=.*/aaa=xxx/'

If you want to guarantee that the aaa= is at the start of the line, make it:

sed 's/^aaa=.*/aaa=xxx/'

SELECT DISTINCT on one column

SELECT min (id) AS 'ID', min(sku) AS 'SKU', Product
    FROM TestData
    WHERE sku LIKE 'FOO%' -- If you want only the sku that matchs with FOO%
    GROUP BY product 
    ORDER BY 'ID'

How to check if a particular service is running on Ubuntu

run

ps -ef | grep name-related-to-process

above command will give all the details like pid, start time about the process.

like if you want all java realted process give java or if you have name of process place the name

Wait for page load in Selenium

You can explicitly wait for an element to show up on the webpage before you can take any action (like element.click())

driver.get("http://somedomain/url_that_delays_loading");
WebElement myDynamicElement = (new WebDriverWait(driver, 10))
  .until(new ExpectedCondition<WebElement>(){
        @Override
        public WebElement apply(WebDriver d) {
        return d.findElement(By.id("myDynamicElement"));
}});

This is what I used for a similar scenario and it works fine.

"Fade" borders in CSS

You can specify gradients for colours in certain circumstances in CSS3, and of course borders can be set to a colour, so you should be able to use a gradient as a border colour. This would include the option of specifying a transparent colour, which means you should be able to achieve the effect you're after.

However, I've never seen it used, and I don't know how well supported it is by current browsers. You'll certainly need to accept that at least some of your users won't be able to see it.

A quick google turned up these two pages which should help you on your way:

Hope that helps.

How to create a fix size list in python?

You can do it using array module. array module is part of python standard library:

from array import array
from itertools import repeat

a = array("i", repeat(0, 10))
# or
a = array("i", [0]*10)

repeat function repeats 0 value 10 times. It's more memory efficient than [0]*10, since it doesn't allocate memory, but repeats returning the same number x number of times.

What are the differences between "=" and "<-" assignment operators in R?

Google's R style guide simplifies the issue by prohibiting the "=" for assignment. Not a bad choice.

https://google.github.io/styleguide/Rguide.xml

The R manual goes into nice detail on all 5 assignment operators.

http://stat.ethz.ch/R-manual/R-patched/library/base/html/assignOps.html

How do I calculate square root in Python?

/ performs an integer division in Python 2:

>>> 1/2
0

If one of the numbers is a float, it works as expected:

>>> 1.0/2
0.5
>>> 16**(1.0/2)
4.0

How to create a generic array?

You should not mix-up arrays and generics. They don't go well together. There are differences in how arrays and generic types enforce the type check. We say that arrays are reified, but generics are not. As a result of this, you see these differences working with arrays and generics.

Arrays are covariant, Generics are not:

What that means? You must be knowing by now that the following assignment is valid:

Object[] arr = new String[10];

Basically, an Object[] is a super type of String[], because Object is a super type of String. This is not true with generics. So, the following declaration is not valid, and won't compile:

List<Object> list = new ArrayList<String>(); // Will not compile.

Reason being, generics are invariant.

Enforcing Type Check:

Generics were introduced in Java to enforce stronger type check at compile time. As such, generic types don't have any type information at runtime due to type erasure. So, a List<String> has a static type of List<String> but a dynamic type of List.

However, arrays carry with them the runtime type information of the component type. At runtime, arrays use Array Store check to check whether you are inserting elements compatible with actual array type. So, the following code:

Object[] arr = new String[10];
arr[0] = new Integer(10);

will compile fine, but will fail at runtime, as a result of ArrayStoreCheck. With generics, this is not possible, as the compiler will try to prevent the runtime exception by providing compile time check, by avoiding creation of reference like this, as shown above.

So, what's the issue with Generic Array Creation?

Creation of array whose component type is either a type parameter, a concrete parameterized type or a bounded wildcard parameterized type, is type-unsafe.

Consider the code as below:

public <T> T[] getArray(int size) {
    T[] arr = new T[size];  // Suppose this was allowed for the time being.
    return arr;
}

Since the type of T is not known at runtime, the array created is actually an Object[]. So the above method at runtime will look like:

public Object[] getArray(int size) {
    Object[] arr = new Object[size];
    return arr;
}

Now, suppose you call this method as:

Integer[] arr = getArray(10);

Here's the problem. You have just assigned an Object[] to a reference of Integer[]. The above code will compile fine, but will fail at runtime.

That is why generic array creation is forbidden.

Why typecasting new Object[10] to E[] works?

Now your last doubt, why the below code works:

E[] elements = (E[]) new Object[10];

The above code have the same implications as explained above. If you notice, the compiler would be giving you an Unchecked Cast Warning there, as you are typecasting to an array of unknown component type. That means, the cast may fail at runtime. For e.g, if you have that code in the above method:

public <T> T[] getArray(int size) {
    T[] arr = (T[])new Object[size];        
    return arr;
}

and you call invoke it like this:

String[] arr = getArray(10);

this will fail at runtime with a ClassCastException. So, no this way will not work always.

What about creating an array of type List<String>[]?

The issue is the same. Due to type erasure, a List<String>[] is nothing but a List[]. So, had the creation of such arrays allowed, let's see what could happen:

List<String>[] strlistarr = new List<String>[10];  // Won't compile. but just consider it
Object[] objarr = strlistarr;    // this will be fine
objarr[0] = new ArrayList<Integer>(); // This should fail but succeeds.

Now the ArrayStoreCheck in the above case will succeed at runtime although that should have thrown an ArrayStoreException. That's because both List<String>[] and List<Integer>[] are compiled to List[] at runtime.

So can we create array of unbounded wildcard parameterized types?

Yes. The reason being, a List<?> is a reifiable type. And that makes sense, as there is no type associated at all. So there is nothing to loose as a result of type erasure. So, it is perfectly type-safe to create an array of such type.

List<?>[] listArr = new List<?>[10];
listArr[0] = new ArrayList<String>();  // Fine.
listArr[1] = new ArrayList<Integer>(); // Fine

Both the above case is fine, because List<?> is super type of all the instantiation of the generic type List<E>. So, it won't issue an ArrayStoreException at runtime. The case is same with raw types array. As raw types are also reifiable types, you can create an array List[].

So, it goes like, you can only create an array of reifiable types, but not non-reifiable types. Note that, in all the above cases, declaration of array is fine, it's the creation of array with new operator, which gives issues. But, there is no point in declaring an array of those reference types, as they can't point to anything but null (Ignoring the unbounded types).

Is there any workaround for E[]?

Yes, you can create the array using Array#newInstance() method:

public <E> E[] getArray(Class<E> clazz, int size) {
    @SuppressWarnings("unchecked")
    E[] arr = (E[]) Array.newInstance(clazz, size);

    return arr;
}

Typecast is needed because that method returns an Object. But you can be sure that it's a safe cast. So, you can even use @SuppressWarnings on that variable.

AngularJS - Trigger when radio button is selected

In newer versions of angular (I'm using 1.3) you can basically set the model and the value and the double binding do all the work this example works like a charm:

_x000D_
_x000D_
angular.module('radioExample', []).controller('ExampleController', ['$scope', function($scope) {_x000D_
  $scope.color = {_x000D_
    name: 'blue'_x000D_
  };_x000D_
}]);
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.15/angular.min.js"></script>_x000D_
<html>_x000D_
<body ng-app="radioExample">_x000D_
<form name="myForm" ng-controller="ExampleController">_x000D_
  <input type="radio" ng-model="color.name" value="red">  Red <br/>_x000D_
  <input type="radio" ng-model="color.name" value="green"> Green <br/>_x000D_
  <input type="radio" ng-model="color.name" value="blue"> Blue <br/>_x000D_
  <tt>color = {{color.name}}</tt><br/>_x000D_
 </form>_x000D_
  </body>_x000D_
</html>
_x000D_
_x000D_
_x000D_

Converting a Uniform Distribution to a Normal Distribution

Changing the distribution of any function to another involves using the inverse of the function you want.

In other words, if you aim for a specific probability function p(x) you get the distribution by integrating over it -> d(x) = integral(p(x)) and use its inverse: Inv(d(x)). Now use the random probability function (which have uniform distribution) and cast the result value through the function Inv(d(x)). You should get random values cast with distribution according to the function you chose.

This is the generic math approach - by using it you can now choose any probability or distribution function you have as long as it have inverse or good inverse approximation.

Hope this helped and thanks for the small remark about using the distribution and not the probability itself.

Python method for reading keypress?

I really did not want to post this as a comment because I would need to comment all answers and the original question.

All of the answers seem to rely on MSVCRT Microsoft Visual C Runtime. If you would like to avoid that dependency :

In case you want cross platform support, using the library here:

https://pypi.org/project/getkey/#files

https://github.com/kcsaff/getkey

Can allow for a more elegant solution.

Code example:

from getkey import getkey, keys
key = getkey()
if key == keys.UP:
  ...  # Handle the UP key
elif key == keys.DOWN:
  ...  # Handle the DOWN key
elif key == 'a':
  ...  # Handle the `a` key
elif key == 'Y':
  ...  # Handle `shift-y`
else:
  # Handle other text characters
  buffer += key
  print(buffer)

Responsive width Facebook Page Plugin

Hi everybody!

My version with a live demonstration(native JavaScript):

1). Javascript code in a separate file (the best solution):

Codepen

_x000D_
_x000D_
/* Vanilla JS */_x000D_
function setupFBframe(frame) {_x000D_
  var container = frame.parentNode;_x000D_
_x000D_
  var containerWidth = container.offsetWidth;_x000D_
  var containerHeight = container.offsetHeight;_x000D_
_x000D_
  var src =_x000D_
    "https://www.facebook.com/plugins/page.php" +_x000D_
    "?href=https%3A%2F%2Fwww.facebook.com%2Ffacebook" +_x000D_
    "&tabs=timeline" +_x000D_
    "&width=" +_x000D_
    containerWidth +_x000D_
    "&height=" +_x000D_
    containerHeight +_x000D_
    "&small_header=false" +_x000D_
    "&adapt_container_width=false" +_x000D_
    "&hide_cover=true" +_x000D_
    "&hide_cta=true" +_x000D_
    "&show_facepile=true" +_x000D_
    "&appId";_x000D_
_x000D_
  frame.width = containerWidth;_x000D_
  frame.height = containerHeight;_x000D_
  frame.src = src;_x000D_
}_x000D_
_x000D_
/* begin Document Ready                                _x000D_
############################################ */_x000D_
_x000D_
document.addEventListener('DOMContentLoaded', function() {_x000D_
  var facebookIframe = document.querySelector('#facebook_iframe');_x000D_
  setupFBframe(facebookIframe);_x000D_
 _x000D_
  /* begin Window Resize                                _x000D_
  ############################################ */_x000D_
  _x000D_
  // Why resizeThrottler? See more : https://developer.mozilla.org/ru/docs/Web/Events/resize_x000D_
  (function() {_x000D_
    window.addEventListener("resize", resizeThrottler, false);_x000D_
_x000D_
    var resizeTimeout;_x000D_
_x000D_
    function resizeThrottler() {_x000D_
      if (!resizeTimeout) {_x000D_
        resizeTimeout = setTimeout(function() {_x000D_
          resizeTimeout = null;_x000D_
          actualResizeHandler();_x000D_
        }, 66);_x000D_
      }_x000D_
    }_x000D_
_x000D_
    function actualResizeHandler() {_x000D_
      document.querySelector('#facebook_iframe').removeAttribute('src');_x000D_
      setupFBframe(facebookIframe);_x000D_
    }_x000D_
  })();_x000D_
  /* end Window Resize_x000D_
  ############################################ */_x000D_
});_x000D_
/* end Document Ready                                _x000D_
############################################ */
_x000D_
@import url('https://fonts.googleapis.com/css?family=Indie+Flower');_x000D_
body {_x000D_
  font-family: 'Indie Flower', cursive;_x000D_
}_x000D_
.container {_x000D_
  max-width: 1170px;_x000D_
  width: 100%;_x000D_
  margin-left: auto;_x000D_
  margin-right: auto;_x000D_
}_x000D_
.content {_x000D_
  overflow: hidden;_x000D_
}_x000D_
_x000D_
.left_sidebar {_x000D_
  position: relative;_x000D_
  float: left;_x000D_
  width: 30%;_x000D_
  max-width: 300px;_x000D_
}_x000D_
_x000D_
.main_content {_x000D_
  position: relative;_x000D_
  float: left;_x000D_
  width: 70%;_x000D_
  background-color: #DDEFF7;_x000D_
}_x000D_
/* ------- begin Widget Facebook -------------- */_x000D_
.widget--facebook--container {_x000D_
  padding: 10px;_x000D_
  border: 1px solid #000;_x000D_
}_x000D_
_x000D_
.widget-facebook {_x000D_
  height: 500px;_x000D_
}_x000D_
_x000D_
.widget-facebook .facebook_iframe {_x000D_
  border: none;_x000D_
}_x000D_
_x000D_
/* ---------- end Widget Facebook---------------- */_x000D_
_x000D_
/* ----------------- no need -------------------- */_x000D_
.block {_x000D_
  color: #fff;_x000D_
  height: 300px;_x000D_
  background-color: #00A7F7;_x000D_
  border: 1px solid #005dff;_x000D_
}_x000D_
_x000D_
.block h3 {_x000D_
  line-height: 300px;_x000D_
  text-align: center;_x000D_
}
_x000D_
<!-- Min. responsive 180px -->_x000D_
<div class="container">_x000D_
  <div class="content">_x000D_
    <div class="left_sidebar">_x000D_
      <aside class="block">_x000D_
        <h3>Content</h3>_x000D_
      </aside>_x000D_
      <!-- begin Widget Facebook_x000D_
    ========================================= -->_x000D_
      <aside class="widget--facebook--container">_x000D_
        <div class="widget-facebook">_x000D_
          <iframe id="facebook_iframe" class="facebook_iframe"></iframe>_x000D_
        </div>_x000D_
      </aside>_x000D_
      <!-- end Widget Facebook_x000D_
      ========================================= -->_x000D_
      <aside class="block">_x000D_
        <h3>Content</h3>_x000D_
      </aside>_x000D_
    </div>_x000D_
    <div class="main_content">_x000D_
      <h1>Responsive width Facebook Page Plugin</h1>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
    </div>_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

2). Javascript code is written in HTML:

Codepen

_x000D_
_x000D_
@import url('https://fonts.googleapis.com/css?family=Indie+Flower');_x000D_
body {_x000D_
  font-family: 'Indie Flower', cursive;_x000D_
}_x000D_
_x000D_
.container {_x000D_
  max-width: 1170px;_x000D_
  width: 100%;_x000D_
  margin-left: auto;_x000D_
  margin-right: auto;_x000D_
}_x000D_
_x000D_
.content {_x000D_
  overflow: hidden;_x000D_
}_x000D_
_x000D_
.left_sidebar {_x000D_
  position: relative;_x000D_
  float: left;_x000D_
  width: 30%;_x000D_
  max-width: 300px;_x000D_
}_x000D_
_x000D_
.main_content {_x000D_
  position: relative;_x000D_
  float: left;_x000D_
  width: 70%;_x000D_
  background-color: #DDEFF7;_x000D_
}_x000D_
_x000D_
_x000D_
/* ------- begin Widget Facebook -------------- */_x000D_
_x000D_
.widget--facebook--container {_x000D_
  padding: 10px;_x000D_
  border: 1px solid #000;_x000D_
}_x000D_
_x000D_
.widget-facebook {_x000D_
  height: 500px;_x000D_
}_x000D_
_x000D_
.widget-facebook .facebook_iframe {_x000D_
  border: none;_x000D_
}_x000D_
_x000D_
_x000D_
/* ---------- end Widget Facebook---------------- */_x000D_
_x000D_
_x000D_
/* ----------------- no need -------------------- */_x000D_
_x000D_
.block {_x000D_
  color: #fff;_x000D_
  height: 300px;_x000D_
  background-color: #00A7F7;_x000D_
  border: 1px solid #005dff;_x000D_
}_x000D_
_x000D_
.block h3 {_x000D_
  line-height: 300px;_x000D_
  text-align: center;_x000D_
}
_x000D_
<!-- Vanilla JS -->_x000D_
<!-- Min. responsive 180px -->_x000D_
<div class="container">_x000D_
  <div class="content">_x000D_
    <div class="left_sidebar">_x000D_
      <aside class="block">_x000D_
        <h3>Content</h3>_x000D_
      </aside>_x000D_
      <!-- begin Widget Facebook_x000D_
      ========================================= -->_x000D_
      <aside class="widget--facebook--container">_x000D_
        <div class="widget-facebook">_x000D_
          <script>_x000D_
            function setupFBframe(frame) {_x000D_
              if (frame.src) return; // already set up_x000D_
_x000D_
              var container = frame.parentNode;_x000D_
              console.log(frame.parentNode);_x000D_
_x000D_
              var containerWidth = container.offsetWidth;_x000D_
              var containerHeight = container.offsetHeight;_x000D_
_x000D_
              var src =_x000D_
                "https://www.facebook.com/plugins/page.php" +_x000D_
                "?href=https%3A%2F%2Fwww.facebook.com%2Ffacebook" +_x000D_
                "&tabs=timeline" +_x000D_
                "&width=" +_x000D_
                containerWidth +_x000D_
                "&height=" +_x000D_
                containerHeight +_x000D_
                "&small_header=false" +_x000D_
                "&adapt_container_width=false" +_x000D_
                "&hide_cover=true" +_x000D_
                "&hide_cta=true" +_x000D_
                "&show_facepile=true" +_x000D_
                "&appId";_x000D_
_x000D_
              frame.width = containerWidth;_x000D_
              frame.height = containerHeight;_x000D_
              frame.src = src;_x000D_
            }_x000D_
_x000D_
            var facebookIframe;_x000D_
_x000D_
            /* begin Window Resize                                _x000D_
            ############################################ */_x000D_
_x000D_
            // Why resizeThrottler? See more : https://developer.mozilla.org/ru/docs/Web/Events/resize_x000D_
            (function() {_x000D_
              window.addEventListener("resize", resizeThrottler, false);_x000D_
_x000D_
              var resizeTimeout;_x000D_
_x000D_
              function resizeThrottler() {_x000D_
                if (!resizeTimeout) {_x000D_
                  resizeTimeout = setTimeout(function() {_x000D_
                    resizeTimeout = null;_x000D_
                    actualResizeHandler();_x000D_
                  }, 66);_x000D_
                }_x000D_
              }_x000D_
_x000D_
              function actualResizeHandler() {_x000D_
                document.querySelector('#facebook_iframe').removeAttribute('src');_x000D_
                setupFBframe(facebookIframe);_x000D_
              }_x000D_
            })();_x000D_
            /* end Window Resize_x000D_
            ############################################ */_x000D_
          </script>_x000D_
          <iframe id="facebook_iframe" class="facebook_iframe" onload="facebookIframe = this; setupFBframe(facebookIframe)"></iframe>_x000D_
        </div>_x000D_
      </aside>_x000D_
      <!-- end Widget Facebook_x000D_
      ========================================= -->_x000D_
      <aside class="block">_x000D_
        <h3>Content</h3>_x000D_
      </aside>_x000D_
    </div>_x000D_
    <div class="main_content">_x000D_
      <h1>Responsive width Facebook Page Plugin</h1>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Laborum earum, temporibus, maxime repudiandae obcaecati veritatis, odio dolore provident tenetur perferendis ipsam, rem esse vitae laudantium voluptatem iste aliquam optio ab.</p>_x000D_
    </div>_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Thanks storsoc!

All the best to you all and have a nice day!

Webview load html from assets directory

You are getting the WebView before setting the Content view so the wv is probably null.

public class ViewWeb extends Activity {  
        @Override  
        public void onCreate(Bundle savedInstanceState) {  
            super.onCreate(savedInstanceState);
            setContentView(R.layout.webview);  
            WebView wv;  
            wv = (WebView) findViewById(R.id.webView1);  
            wv.loadUrl("file:///android_asset/aboutcertified.html");   // now it will not fail here
        }  
    }

An invalid form control with name='' is not focusable

In case anyone else has this issue, I experienced the same thing. As discussed in the comments, it was due to the browser attempting to validate hidden fields. It was finding empty fields in the form and trying to focus on them, but because they were set to display:none;, it couldn't. Hence the error.

I was able to solve it by using something similar to this:

$("body").on("submit", ".myForm", function(evt) {

    // Disable things that we don't want to validate.
    $(["input:hidden, textarea:hidden, select:hidden"]).attr("disabled", true);

    // If HTML5 Validation is available let it run. Otherwise prevent default.
    if (this.el.checkValidity && !this.el.checkValidity()) {
        // Re-enable things that we previously disabled.
        $(["input:hidden, textarea:hidden, select:hidden"]).attr("disabled", false);
        return true;
    }
    evt.preventDefault();

    // Re-enable things that we previously disabled.
    $(["input:hidden, textarea:hidden, select:hidden"]).attr("disabled", false);

    // Whatever other form processing stuff goes here.
});

Also, this is possibly a duplicate of "Invalid form control" only in Google Chrome

How to read a text file directly from Internet using Java?

Using Apache Commons IO:

import org.apache.commons.io.IOUtils;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.nio.charset.StandardCharsets;

public static String readURLToString(String url) throws IOException
{
    try (InputStream inputStream = new URL(url).openStream())
    {
        return IOUtils.toString(inputStream, StandardCharsets.UTF_8);
    }
}

How can I deploy an iPhone application from Xcode to a real iPhone device?

I was going through the Apple Developer last night and there in the Provisioning Certificate I found something like - "Signing Team Members". I think there is a way to add team members to the paid profile. You can just ask to the App Id Owner(paid one) to add you as a team member. I am not sure. Still searching on that.

Use of Greater Than Symbol in XML

Use &gt; and &lt; for 'greater-than' and 'less-than' respectively

Dynamically adding elements to ArrayList in Groovy

The Groovy way to do this is

def list = []
list << new MyType(...)

which creates a list and uses the overloaded leftShift operator to append an item

See the Groovy docs on Lists for lots of examples.

CHECK constraint in MySQL is not working

Check constraints are supported as of version 8.0.15 (yet to be released)

https://bugs.mysql.com/bug.php?id=3464

[23 Jan 16:24] Paul Dubois

Posted by developer: Fixed in 8.0.15.

Previously, MySQL permitted a limited form of CHECK constraint syntax, but parsed and ignored it. MySQL now implements the core features of table and column CHECK constraints, for all storage engines. Constraints are defined using CREATE TABLE and ALTER TABLE statements.

Creating a chart in Excel that ignores #N/A or blank cells

Select the labels above the bar. Format Data Labels. Instead of selecting "VALUE" (unclick). SELECT Value from cells. Select the value. Use the following statement: if(cellvalue="","",cellvalue) where cellvalue is what ever the calculation is in the cell.

Parse string to DateTime in C#

Try the following code

Month = Date = DateTime.Now.Month.ToString();   
Year = DateTime.Now.Year.ToString(); 
ViewBag.Today = System.Globalization.CultureInfo.InvariantCulture.DateTimeFormat.GetMonthName(Int32.Parse(Month)) + Year;

How to easily import multiple sql files into a MySQL database?

  1. Goto cmd

  2. Type in command prompt C:\users\Usersname>cd [.sql tables folder path ]
    Press Enter
    Ex: C:\users\Usersname>cd E:\project\database

  3. Type command prompt
    C:\users\Usersname>[.sql folder's drive (directory)name]
    Press Enter
    Ex: C:\users\Usersname>E:

  4. Type command prompt for marge all .sql file(table) in a single file
    copy /b *.sql newdatabase.sql
    Press Enter
    EX: E:\project\database>copy /b *.sql newdatabase.sql

  5. You can see Merge Multiple .sql(file) tables Files Into A Single File in your directory folder
    Ex: E:\project\database

Installing SQL Server 2012 - Error: Prior Visual Studio 2010 instances requiring update

I had this same problem installing SQL Server 2014. Turns out it was due to a Windows Phone toolkit that I had installed back in 2010. If you run into this, make sure you uninstall any Windows phone stuff that isn't current.

I figured it out by looking at the log, which can be found by clicking "Detailed Report," which opens an HTML file. The file path is conveniently displayed within the HTML page. Open the directory that the file is in and look for "Detail.txt." Then search for the word "fail."

In my case there was a line showing WP_[something] as "Installed." I searched for the WP_ item and came across some blog posts about trouble uninstalling Windows Phone toolkits.

When I attempted to uninstall the windows phone I ran into more trouble. The uninstaller wanted to install three packages instead of uninstalling the toolkit. Eventually found this blog post: http://blogs.msdn.com/b/astebner/archive/2010/07/12/10037442.aspx linking to this XNA cleanup tool: http://blogs.msdn.com/b/astebner/archive/2009/04/10/9544320.aspx.

I ran the cleanup tool and finally SQL Server installer passed the check and allowed me to install. Hope this helps someone.

The activity must be exported or contain an intent-filter

Check your manifest,Open the file with .xml extension and then all your activities are listed your first activity should have this code enclosed in its tags

<intent-filter>
    <category android:name="android.intent.category.LAUNCHER" />
</intent-filter>

or there is another way u can choose from configuration which is drop down list on the left side of run button choose from App from it Hope it will help!!

Highlight label if checkbox is checked

If you have

<div>
  <input type="checkbox" class="check-with-label" id="idinput" />
  <label class="label-for-check" for="idinput">My Label</label>
</div>

you can do

.check-with-label:checked + .label-for-check {
  font-weight: bold;
}

See this working. Note that this won't work in non-modern browsers.

How to get a list of images on docker registry v2

If some on get this far.

Taking what others have already said above. Here is a one-liner that puts the answer into a text file formatted, json.

curl "http://mydocker.registry.domain/v2/_catalog?n=2000" | jq . - > /tmp/registry.lst

This looks like

{
  "repositories": [
    "somerepo/somecontiner",
    "somerepo_other/someothercontiner",
 ...
  ]
}

You might need to change the `?n=xxxx' to match how many containers you have.

Next is a way to automatically remove old and unused containers.

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

The lazy/hurry alternative (Dotnet Core 2.2):

[HttpGet("method1-{item}")]
public string Method1(var item) { 
return "hello" + item;}

[HttpGet("method2-{item}")]
public string Method2(var item) { 
return "world" + item;}

Calling them :

localhost:5000/api/controllername/method1-42

"hello42"

localhost:5000/api/controllername/method2-99

"world99"

Regex number between 1 and 100

If one assumes he really needs regexp - which is perfectly reasonable in many contexts - the problem is that the specific regexp variety needs to be specified. For example:

egrep '^(100|[1-9]|[1-9][0-9])$'
grep -E '^(100|[1-9]|[1-9][0-9])$'

work fine if the (...|...) alternative syntax is available. In other contexts, they'd be backslashed like \(...\|...\)

SQL Error: ORA-00933: SQL command not properly ended

Semicolon ; on the end of command had caused the same error on me.

cmd.CommandText = "INSERT INTO U_USERS_TABLE (USERNAME, PASSWORD, FIRSTNAME, LASTNAME) VALUES ("
                + "'" + txtUsername.Text + "',"
                + "'" + txtPassword.Text + "',"
                + "'" + txtFirstname.Text + "',"
                + "'" + txtLastname.Text + "');"; <== Semicolon in "" is the cause.
                                                      Removing it will be fine.

Hope it helps.

Generating unique random numbers (integers) between 0 and 'x'

These answers either don't give unique values, or are so long (one even adding an external library to do such a simple task).

1. generate a random number.
2. if we have this random already then goto 1, else keep it.
3. if we don't have desired quantity of randoms, then goto 1.

_x000D_
_x000D_
function uniqueRandoms(qty, min, max){_x000D_
  var rnd, arr=[];_x000D_
  do { do { rnd=Math.floor(Math.random()*max)+min }_x000D_
      while(arr.includes(rnd))_x000D_
      arr.push(rnd);_x000D_
  } while(arr.length<qty)_x000D_
  return arr;_x000D_
}_x000D_
_x000D_
//generate 5 unique numbers between 1 and 10_x000D_
console.log( uniqueRandoms(5, 1, 10) );
_x000D_
_x000D_
_x000D_

...and a compressed version of the same function:

function uniqueRandoms(qty,min,max){var a=[];do{do{r=Math.floor(Math.random()*max)+min}while(a.includes(r));a.push(r)}while(a.length<qty);return a}

Writing Unicode text to a text file?

In case of writing in python3

>>> a = u'bats\u00E0'
>>> print a
batsà
>>> f = open("/tmp/test", "w")
>>> f.write(a)
>>> f.close()
>>> data = open("/tmp/test").read()
>>> data
'batsà'

In case of writing in python2:

>>> a = u'bats\u00E0'
>>> f = open("/tmp/test", "w")
>>> f.write(a)

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
UnicodeEncodeError: 'ascii' codec can't encode character u'\xe0' in position 4: ordinal not in range(128)

To avoid this error you would have to encode it to bytes using codecs "utf-8" like this:

>>> f.write(a.encode("utf-8"))
>>> f.close()

and decode the data while reading using the codecs "utf-8":

>>> data = open("/tmp/test").read()
>>> data.decode("utf-8")
u'bats\xe0'

And also if you try to execute print on this string it will automatically decode using the "utf-8" codecs like this

>>> print a
batsà

Run java jar file on a server as background process

You can try this:

#!/bin/sh
nohup java -jar /web/server.jar &

The & symbol, switches the program to run in the background.

The nohup utility makes the command passed as an argument run in the background even after you log out.

How to save .xlsx data to file as a blob

Here's my implementation using the fetch api. The server endpoint sends a stream of bytes and the client receives a byte array and creates a blob out of it. A .xlsx file will then be generated.

return fetch(fullUrlEndpoint, options)
  .then((res) => {
    if (!res.ok) {
      const responseStatusText = res.statusText
      const errorMessage = `${responseStatusText}`
      throw new Error(errorMessage);
    }
    return res.arrayBuffer();
  })
    .then((ab) => {
      // BE endpoint sends a readable stream of bytes
      const byteArray = new Uint8Array(ab);
      const a = window.document.createElement('a');
      a.href = window.URL.createObjectURL(
        new Blob([byteArray], {
          type:
            'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
        }),
      );
      a.download = `${fileName}.XLSX`;
      document.body.appendChild(a);
      a.click();
      document.body.removeChild(a);
    })
    .catch(error => {
      throw new Error('Error occurred:' + error);
    });

Find the greatest number in a list of numbers

    #Ask for number input
first = int(raw_input('Please type a number: '))
second = int(raw_input('Please type a number: '))
third = int(raw_input('Please type a number: '))
fourth = int(raw_input('Please type a number: '))
fifth = int(raw_input('Please type a number: '))
sixth = int(raw_input('Please type a number: '))
seventh = int(raw_input('Please type a number: '))
eighth = int(raw_input('Please type a number: '))
ninth = int(raw_input('Please type a number: '))
tenth = int(raw_input('Please type a number: '))

    #create a list for variables
sorted_list = [first, second, third, fourth, fifth, sixth, seventh, 
              eighth, ninth, tenth]
odd_numbers = []

    #filter list and add odd numbers to new list
for value in sorted_list:
    if value%2 != 0:
        odd_numbers.append(value)
print 'The greatest odd number you typed was:', max(odd_numbers)

Matching a Forward Slash with a regex

You need to escape the / with a \.

/\//ig // matches /

jQuery hasClass() - check for more than one class

$.fn.extend({
    hasClasses: function (selectors) {
        var self = this;
        for (var i in selectors) {
            if ($(self).hasClass(selectors[i])) 
                return true;
        }
        return false;
    }
});

$('#element').hasClasses(['class1', 'class2', 'class3']);

This should do it, simple and easy.

Why is System.Web.Mvc not listed in Add References?

If you got this problem in Visual Studio 2017, chances are you're working with an MVC 4 project created in a previous version of VS with a reference hint path pointing to C:\Program Files (x86)\Microsoft ASP.NET. Visual Studio 2017 does not install this directory anymore.

We usually solve this by installing a copy of Visual Studio 2015 alongside our 2017 instance, and that installs the necessary libraries in the above path. Then we update all the references in the affected projects and we're good to go.

Does a foreign key automatically create an index?

I notice that Entity Framework 6.1 pointed at MSSQL does automatically add indexes on foreign keys.

How would I get a cron job to run every 30 minutes?

You can use both of ',' OR divide '/' symbols.
But, '/' is better.
Suppose the case of 'every 5 minutes'. If you use ',', you have to write the cron job as following:

0,5,10,15,20,25,30,35,....    *      *     *   * your_command

It means run your_command in every hour in all of defined minutes: 0,5,10,...

However, if you use '/', you can write the following simple and short job:

*/5  *  *  *  *  your_command

It means run your_command in the minutes that are dividable by 5 or in the simpler words, '0,5,10,...'

So, dividable symbol '/' is the best choice always;

Could not find method android() for arguments

You are using the wrong build.gradle file.

In your top-level file you can't define an android block.

Just move this part inside the module/build.gradle file.

android {
    compileSdkVersion 17
    buildToolsVersion '23.0.0'
}
dependencies {
    compile files('app/libs/junit-4.12-JavaDoc.jar')
}
apply plugin: 'maven'

Expansion of variables inside single quotes in a command in Bash

Inside single quotes everything is preserved literally, without exception.

That means you have to close the quotes, insert something, and then re-enter again.

'before'"$variable"'after'
'before'"'"'after'
'before'\''after'

Word concatenation is simply done by juxtaposition. As you can verify, each of the above lines is a single word to the shell. Quotes (single or double quotes, depending on the situation) don't isolate words. They are only used to disable interpretation of various special characters, like whitespace, $, ;... For a good tutorial on quoting see Mark Reed's answer. Also relevant: Which characters need to be escaped in bash?

Do not concatenate strings interpreted by a shell

You should absolutely avoid building shell commands by concatenating variables. This is a bad idea similar to concatenation of SQL fragments (SQL injection!).

Usually it is possible to have placeholders in the command, and to supply the command together with variables so that the callee can receive them from the invocation arguments list.

For example, the following is very unsafe. DON'T DO THIS

script="echo \"Argument 1 is: $myvar\""
/bin/sh -c "$script"

If the contents of $myvar is untrusted, here is an exploit:

myvar='foo"; echo "you were hacked'

Instead of the above invocation, use positional arguments. The following invocation is better -- it's not exploitable:

script='echo "arg 1 is: $1"'
/bin/sh -c "$script" -- "$myvar"

Note the use of single ticks in the assignment to script, which means that it's taken literally, without variable expansion or any other form of interpretation.

How to switch between hide and view password

I had the same issue and it is very easy to implement.

All you have to do is wrap your EditText field in a (com.google.android.material.textfield.TextInputLayout) and in that add ( app:passwordToggleEnabled="true" ).

This will show the eye in the EditText field and when you click on it the password will appear and disappear when clicked again.

<com.google.android.material.textfield.TextInputLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:textColorHint="#B9B8B8"
                app:passwordToggleEnabled="true">

                <EditText
                    android:id="@+id/register_password"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginLeft="24dp"
                    android:layout_marginRight="44dp"
                    android:backgroundTint="#BEBEBE"
                    android:hint="Password"
                    android:inputType="textPassword"
                    android:padding="16dp"
                    android:textSize="18sp" />
            </com.google.android.material.textfield.TextInputLayout>

What is meant with "const" at end of function declaration?

A "const function", denoted with the keyword const after a function declaration, makes it a compiler error for this class function to change a member variable of the class. However, reading of a class variables is okay inside of the function, but writing inside of this function will generate a compiler error.

Another way of thinking about such "const function" is by viewing a class function as a normal function taking an implicit this pointer. So a method int Foo::Bar(int random_arg) (without the const at the end) results in a function like int Foo_Bar(Foo* this, int random_arg), and a call such as Foo f; f.Bar(4) will internally correspond to something like Foo f; Foo_Bar(&f, 4). Now adding the const at the end (int Foo::Bar(int random_arg) const) can then be understood as a declaration with a const this pointer: int Foo_Bar(const Foo* this, int random_arg). Since the type of this in such case is const, no modifications of member variables are possible.

It is possible to loosen the "const function" restriction of not allowing the function to write to any variable of a class. To allow some of the variables to be writable even when the function is marked as a "const function", these class variables are marked with the keyword mutable. Thus, if a class variable is marked as mutable, and a "const function" writes to this variable then the code will compile cleanly and the variable is possible to change. (C++11)

As usual when dealing with the const keyword, changing the location of the const key word in a C++ statement has entirely different meanings. The above usage of const only applies when adding const to the end of the function declaration after the parenthesis.

const is a highly overused qualifier in C++: the syntax and ordering is often not straightforward in combination with pointers. Some readings about const correctness and the const keyword:

Const correctness

The C++ 'const' Declaration: Why & How

Is there an advantage to use a Synchronized Method instead of a Synchronized Block?

Often using a lock on a method level is too rude. Why lock up a piece of code that does not access any shared resources by locking up an entire method. Since each object has a lock, you can create dummy objects to implement block level synchronization. The block level is more efficient because it does not lock the whole method.

Here some example

Method Level

class MethodLevel {

  //shared among threads
SharedResource x, y ;

public void synchronized method1() {
   //multiple threads can't access
}
public void synchronized method2() {
  //multiple threads can't access
}

 public void method3() {
  //not synchronized
  //multiple threads can access
 }
}

Block Level

class BlockLevel {
  //shared among threads
  SharedResource x, y ;

  //dummy objects for locking
  Object xLock = new Object();
  Object yLock = new Object();

    public void method1() {
     synchronized(xLock){
    //access x here. thread safe
    }

    //do something here but don't use SharedResource x, y
    // because will not be thread-safe
     synchronized(xLock) {
       synchronized(yLock) {
      //access x,y here. thread safe
      }
     }

     //do something here but don't use SharedResource x, y
     //because will not be thread-safe
    }//end of method1
 }

[Edit]

For Collection like Vector and Hashtable they are synchronized when ArrayList or HashMap are not and you need set synchronized keyword or invoke Collections synchronized method:

Map myMap = Collections.synchronizedMap (myMap); // single lock for the entire map
List myList = Collections.synchronizedList (myList); // single lock for the entire list

Unused arguments in R

You could use dots: ... in your function definition.

myfun <- function(a, b, ...){
  cat(a,b)
}

myfun(a=4,b=7,hello=3)

# 4 7

Merging two CSV files using Python

When I'm working with csv files, I often use the pandas library. It makes things like this very easy. For example:

import pandas as pd

a = pd.read_csv("filea.csv")
b = pd.read_csv("fileb.csv")
b = b.dropna(axis=1)
merged = a.merge(b, on='title')
merged.to_csv("output.csv", index=False)

Some explanation follows. First, we read in the csv files:

>>> a = pd.read_csv("filea.csv")
>>> b = pd.read_csv("fileb.csv")
>>> a
   title  stage    jan    feb
0   darn  3.001  0.421  0.532
1     ok  2.829  1.036  0.751
2  three  1.115  1.146  2.921
>>> b
   title    mar    apr    may       jun  Unnamed: 5
0   darn  0.631  1.321  0.951    1.7510         NaN
1     ok  1.001  0.247  2.456    0.3216         NaN
2  three  0.285  1.283  0.924  956.0000         NaN

and we see there's an extra column of data (note that the first line of fileb.csv -- title,mar,apr,may,jun, -- has an extra comma at the end). We can get rid of that easily enough:

>>> b = b.dropna(axis=1)
>>> b
   title    mar    apr    may       jun
0   darn  0.631  1.321  0.951    1.7510
1     ok  1.001  0.247  2.456    0.3216
2  three  0.285  1.283  0.924  956.0000

Now we can merge a and b on the title column:

>>> merged = a.merge(b, on='title')
>>> merged
   title  stage    jan    feb    mar    apr    may       jun
0   darn  3.001  0.421  0.532  0.631  1.321  0.951    1.7510
1     ok  2.829  1.036  0.751  1.001  0.247  2.456    0.3216
2  three  1.115  1.146  2.921  0.285  1.283  0.924  956.0000

and finally write this out:

>>> merged.to_csv("output.csv", index=False)

producing:

title,stage,jan,feb,mar,apr,may,jun
darn,3.001,0.421,0.532,0.631,1.321,0.951,1.751
ok,2.829,1.036,0.751,1.001,0.247,2.456,0.3216
three,1.115,1.146,2.921,0.285,1.283,0.924,956.0

Git for beginners: The definitive practical guide

Git Reset

Say you make a pull, merge it into your code, and decide you don't like it. Use git-log, or tig, and find the hash of wherever you want to go back to (probably your last commit before the pull/merge) copy the hash, and do:

# Revert to a previous commit by hash:
git-reset --hard <hash>

Instead of the hash, you can use HEAD^ as a shortcut for the previous commit.

# Revert to previous commit:
git-reset --hard HEAD^

Entity Framework. Delete all rows in table

Warning: The following is only suitable for small tables (think < 1000 rows)

Here is a solution that uses entity framework (not SQL) to delete the rows, so it is not SQL Engine(R/DBM) specific.

This assumes that you're doing this for testing or some similar situation. Either

  • The amount of data is small or
  • The performance doesn't matter

Simply call:

VotingContext.Votes.RemoveRange(VotingContext.Votes);

Assuming this context:

public class VotingContext : DbContext
{
    public DbSet<Vote> Votes{get;set;}
    public DbSet<Poll> Polls{get;set;}
    public DbSet<Voter> Voters{get;set;}
    public DbSet<Candidacy> Candidates{get;set;}
}

For tidier code you can declare the following extension method:

public static class EntityExtensions
{
    public static void Clear<T>(this DbSet<T> dbSet) where T : class
    {
        dbSet.RemoveRange(dbSet);
    }
}

Then the above becomes:

VotingContext.Votes.Clear();
VotingContext.Voters.Clear();
VotingContext.Candidacy.Clear();
VotingContext.Polls.Clear();
await VotingTestContext.SaveChangesAsync();

I recently used this approach to clean up my test database for each testcase run (it´s obviously faster than recreating the DB from scratch each time, though I didn´t check the form of the delete commands that were generated).


Why can it be slow?

  1. EF will get ALL the rows (VotingContext.Votes)
  2. and then will use their IDs (not sure exactly how, doesn't matter), to delete them.

So if you're working with serious amount of data you'll kill the SQL server process (it will consume all the memory) and same thing for the IIS process since EF will cache all the data same way as SQL server. Don't use this one if your table contains serious amount of data.

ValueError: unconverted data remains: 02:05

The value of st at st = datetime.strptime(st, '%A %d %B') line something like 01 01 2013 02:05 and the strptime can't parse this. Indeed, you get an hour in addition of the date... You need to add %H:%M at your strptime.

How to get the ASCII value of a character

To get the ASCII code of a character, you can use the ord() function.

Here is an example code:

value = input("Your value here: ")
list=[ord(ch) for ch in value]
print(list)

Output:

Your value here: qwerty
[113, 119, 101, 114, 116, 121]

Bash foreach loop

Something like this would do:

xargs cat <filenames.txt

The xargs program reads its standard input, and for each line of input runs the cat program with the input lines as argument(s).

If you really want to do this in a loop, you can:

for fn in `cat filenames.txt`; do
    echo "the next file is $fn"
    cat $fn
done

Git push error: "origin does not appear to be a git repository"

As it has already been mentioned in che's answer about adding the remote part, which I believe you are still missing.

Regarding your edit for adding remote on your local USB drive. First of all you must have a 'bare repository' if you want your repository to be a shared repository i.e. to be able to push/pull/fetch/merge etc..

To create a bare/shared repository, go to your desired location. In your case:

$ cd /Volumes/500gb/   
$ git init --bare myproject.git

See here for more info on creating bare repository

Once you have a bare repository set up in your desired location you can now add it to your working copy as a remote.

$ git remote add origin /Volumes/500gb/myproject.git

And now you can push your changes to your repository

$ git push origin master

MySQL - How to select data by string length

The function that I use to find the length of the string is length, used as follows:

SELECT * FROM table ORDER BY length(column);

Flutter - The method was called on null

You should declare your method first in void initState(), so when the first time pages has been loaded, it will init your method first, hope it can help

How to parse XML using vba

This is a bit of a complicated question, but it seems like the most direct route would be to load the XML document or XML string via MSXML2.DOMDocument which will then allow you to access the XML nodes.

You can find more on MSXML2.DOMDocument at the following sites:

How to find out client ID of component for ajax update/render? Cannot find component with expression "foo" referenced from "bar"

first of all: as far as i know placing dialog inside a tabview is a bad practice... you better take it out...

and now to your question:

sorry, took me some time to get what exactly you wanted to implement,

did at my web app myself just now, and it works

as I sayed before place the p:dialog out side the `p:tabView ,

leave the p:dialog as you initially suggested :

<p:dialog modal="true" widgetVar="dlg">
    <h:panelGrid id="display">
        <h:outputText value="Name:" />
        <h:outputText value="#{instrumentBean.selectedInstrument.name}" />
    </h:panelGrid>
</p:dialog>   

and the p:commandlink should look like this (all i did is to change the update attribute)

<p:commandLink update="display" oncomplete="dlg.show()">
    <f:setPropertyActionListener value="#{lndInstrument}" 
        target="#{instrumentBean.selectedInstrument}" />
    <h:outputText value="#{lndInstrument.name}" />
</p:commandLink>  

the same works in my web app, and if it does not work for you , then i guess there is something wrong in your java bean code...

Converting byte array to string in javascript

I think this would be more efficient:

function toBinString (arr) {
    var uarr = new Uint8Array(arr.map(function(x){return parseInt(x,2)}));
    var strings = [], chunksize = 0xffff;
    // There is a maximum stack size. We cannot call String.fromCharCode with as many arguments as we want
    for (var i=0; i*chunksize < uarr.length; i++){
        strings.push(String.fromCharCode.apply(null, uarr.subarray(i*chunksize, (i+1)*chunksize)));
    }
    return strings.join('');
}

Android sample bluetooth code to send a simple string via bluetooth

private OutputStream outputStream;
private InputStream inStream;

private void init() throws IOException {
    BluetoothAdapter blueAdapter = BluetoothAdapter.getDefaultAdapter();
    if (blueAdapter != null) {
        if (blueAdapter.isEnabled()) {
            Set<BluetoothDevice> bondedDevices = blueAdapter.getBondedDevices();

            if(bondedDevices.size() > 0) {
                Object[] devices = (Object []) bondedDevices.toArray();
                BluetoothDevice device = (BluetoothDevice) devices[position];
                ParcelUuid[] uuids = device.getUuids();
                BluetoothSocket socket = device.createRfcommSocketToServiceRecord(uuids[0].getUuid());
                socket.connect();
                outputStream = socket.getOutputStream();
                inStream = socket.getInputStream();
            }

            Log.e("error", "No appropriate paired devices.");
        } else {
            Log.e("error", "Bluetooth is disabled.");
        }
    }
}

public void write(String s) throws IOException {
    outputStream.write(s.getBytes());
}

public void run() {
    final int BUFFER_SIZE = 1024;
    byte[] buffer = new byte[BUFFER_SIZE];
    int bytes = 0;
    int b = BUFFER_SIZE;

    while (true) {
        try {
            bytes = inStream.read(buffer, bytes, BUFFER_SIZE - bytes);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Counting the number of non-NaN elements in a numpy ndarray in Python

np.count_nonzero(~np.isnan(data))

~ inverts the boolean matrix returned from np.isnan.

np.count_nonzero counts values that is not 0\false. .sum should give the same result. But maybe more clearly to use count_nonzero

Testing speed:

In [23]: data = np.random.random((10000,10000))

In [24]: data[[np.random.random_integers(0,10000, 100)],:][:, [np.random.random_integers(0,99, 100)]] = np.nan

In [25]: %timeit data.size - np.count_nonzero(np.isnan(data))
1 loops, best of 3: 309 ms per loop

In [26]: %timeit np.count_nonzero(~np.isnan(data))
1 loops, best of 3: 345 ms per loop

In [27]: %timeit data.size - np.isnan(data).sum()
1 loops, best of 3: 339 ms per loop

data.size - np.count_nonzero(np.isnan(data)) seems to barely be the fastest here. other data might give different relative speed results.