Programs & Examples On #Sqlpubwiz

How to get current user in asp.net core

Most of the answers show how to best handle HttpContext from the documentation, which is also what I went with.

I did want to mention that you'll want to check you project settings when debugging, the default is Enable Anonymous Authentication = true.

SQL WHERE ID IN (id1, id2, ..., idn)

Option 1 is the only good solution.

Why?

  • Option 2 does the same but you repeat the column name lots of times; additionally the SQL engine doesn't immediately know that you want to check if the value is one of the values in a fixed list. However, a good SQL engine could optimize it to have equal performance like with IN. There's still the readability issue though...

  • Option 3 is simply horrible performance-wise. It sends a query every loop and hammers the database with small queries. It also prevents it from using any optimizations for "value is one of those in a given list"

Casting a number to a string in TypeScript

Just utilize toString or toLocaleString I'd say. So:

var page_number:number = 3;
window.location.hash = page_number.toLocaleString();

These throw an error if page_number is null or undefined. If you don't want that you can choose the fix appropriate for your situation:

// Fix 1:
window.location.hash = (page_number || 1).toLocaleString();

// Fix 2a:
window.location.hash = !page_number ? "1" page_number.toLocaleString();

// Fix 2b (allows page_number to be zero):
window.location.hash = (page_number !== 0 && !page_number) ? "1" page_number.toLocaleString();

Android video streaming example

I had the same problem but finally I found the way.

Here is the walk through:

1- Install VLC on your computer (SERVER) and go to Media->Streaming (Ctrl+S)

2- Select a file to stream or if you want to stream your webcam or... click on "Capture Device" tab and do the configuration and finally click on "Stream" button.

3- Here you should do the streaming server configuration, just go to "Option" tab and paste the following command:

:sout=#transcode{vcodec=mp4v,vb=400,fps=10,width=176,height=144,acodec=mp4a,ab=32,channels=1,samplerate=22050}:rtp{sdp=rtsp://YOURCOMPUTER_SERVER_IP_ADDR:5544/}

NOTE: Replace YOURCOMPUTER_SERVER_IP_ADDR with your computer IP address or any server which is running VLC...

NOTE: You can see, the video codec is MP4V which is supported by android.

4- go to eclipse and create a new project for media playbak. create a VideoView object and in the OnCreate() function write some code like this:

mVideoView = (VideoView) findViewById(R.id.surface_view);

mVideoView.setVideoPath("rtsp://YOURCOMPUTER_SERVER_IP_ADDR:5544/");
mVideoView.setMediaController(new MediaController(this));

5- run the apk on the device (not simulator, i did not check it) and wait for the playback to be started. please consider the buffering process will take about 10 seconds...

Question: Anybody know how to reduce buffering time and play video almost live ?

Unable to compile simple Java 10 / Java 11 project with Maven

It might not exactly be the same error, but I had a similar one.

Check Maven Java Version

Since Maven is also runnig with Java, check first with which version your Maven is running on:

mvn --version | grep -i java 

It returns:

Java version 1.8.0_151, vendor: Oracle Corporation, runtime: C:\tools\jdk\openjdk1.8

Incompatible version

Here above my maven is running with Java Version 1.8.0_151. So even if I specify maven to compile with Java 11:

<properties>
    <java.version>11</java.version>
    <maven.compiler.source>${java.version}</maven.compiler.source>
    <maven.compiler.target>${java.version}</maven.compiler.target>
</properties>

It will logically print out this error:

[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.0:compile (default-compile) on project efa-example-commons-task: Fatal error compiling: invalid target release: 11 -> [Help 1]

How to set specific java version to Maven

The logical thing to do is to set a higher Java Version to Maven (e.g. Java version 11 instead 1.8).

Maven make use of the environment variable JAVA_HOME to find the Java Version to run. So change this variable to the JDK you want to compile against (e.g. OpenJDK 11).

Sanity check

Then run again mvn --version to make sure the configuration has been taken care of:

mvn --version | grep -i java

yields

Java version: 11.0.2, vendor: Oracle Corporation, runtime: C:\tools\jdk\openjdk11

Which is much better and correct to compile code written with the Java 11 specifications.

How to get the selected item of a combo box to a string variable in c#

Test this

  var selected = this.ComboBox.GetItemText(this.ComboBox.SelectedItem);
  MessageBox.Show(selected);

Qt - reading from a text file

You have to replace string line

QString line = in.readLine();

into while:

QFile file("/home/hamad/lesson11.txt");
if(!file.open(QIODevice::ReadOnly)) {
    QMessageBox::information(0, "error", file.errorString());
}

QTextStream in(&file);

while(!in.atEnd()) {
    QString line = in.readLine();    
    QStringList fields = line.split(",");    
    model->appendRow(fields);    
}

file.close();

Getting Error:JRE_HOME variable is not defined correctly when trying to run startup.bat of Apache-Tomcat

Got the solution and it's working fine. Set the environment variables as:

  • CATALINA_HOME=C:\Program Files\Java\apache-tomcat-7.0.59\apache-tomcat-7.0.59 (path where your Apache Tomcat is)
  • JAVA_HOME=C:\Program Files\Java\jdk1.8.0_25; (path where your JDK is)
  • JRE_Home=C:\Program Files\Java\jre1.8.0_25; (path where your JRE is)
  • CLASSPATH=%JAVA_HOME%\bin;%JRE_HOME%\bin;%CATALINA_HOME%\lib

Better way to sum a property value in an array

Use reduce with destructuring to sum Amount:

const traveler = [
  { description: 'Senior', Amount: 50 },
  { description: 'Senior', Amount: 50 },
  { description: 'Adult', Amount: 75 },
  { description: 'Child', Amount: 35 },
  { description: 'Infant', Amount: 25 },
];

console.log(traveler.reduce((n, {Amount}) => n + Amount, 0))

Oracle SQL update based on subquery between two tables

There are two ways to do what you are trying

One is a Multi-column Correlated Update

UPDATE PRODUCTION a
SET (name, count) = (
  SELECT name, count
  FROM STAGING b
  WHERE a.ID = b.ID);

DEMO

You can use merge

MERGE INTO PRODUCTION a
USING ( select id, name, count 
          from STAGING ) b
ON ( a.id = b.id )
WHEN MATCHED THEN 
UPDATE SET  a.name = b.name,
            a.count = b.count

DEMO

How do I install and use the ASP.NET AJAX Control Toolkit in my .NET 3.5 web applications?

Install the ASP.NET AJAX Control Toolkit

  1. Download the ZIP file AjaxControlToolkit-Framework3.5SP1-DllOnly.zip from the ASP.NET AJAX Control Toolkit Releases page of the CodePlex web site.

  2. Copy the contents of this zip file directly into the bin directory of your web site.

Update web.config

  1. Put this in your web.config under the <controls> section:

    <?xml version="1.0"?>
    <configuration>
        ...
        <system.web>
            ...
            <pages>
                ...
                <controls>
                    ...
                    <add tagPrefix="ajaxtoolkit"
                        namespace="AjaxControlToolkit"
                        assembly="AjaxControlToolKit"/>
                </controls>
            </pages>
            ...
        </system.web>
        ...
    </configuration>
    

Setup Visual Studio

  1. Right-click on the Toolbox and select "Add Tab", and add a tab called "AJAX Control Toolkit"

  2. Inside that tab, right-click on the Toolbox and select "Choose Items..."

  3. When the "Choose Toolbox Items" dialog appears, click the "Browse..." button. Navigate to your project's "bin" folder. Inside that folder, select "AjaxControlToolkit.dll" and click OK. Click OK again to close the Choose Items Dialog.

You can now use the controls in your web sites!

Import file size limit in PHPMyAdmin

Check your all 3:

  • upload_max_filesize
  • memory_limit
  • post_max_size

in the php.ini configuration file

* for those, who are using wamp @windows, you can follow these steps: *

Also it can be adapted to any phpmyadmin installation.

Find your config.inc.php file for PhpMyAdmin configuration (for wamp it's here: C:\wamp\apps\phpmyadminVERSION\config.inc.php

add this line at the end of the file BEFORE "?>":

$cfg['UploadDir'] = 'C:\wamp\sql';

save

create folder at

C:\wamp\sql 

copy your huge sql file there.

Restart server.

Go to your phpmyadmin import tab and you'll see a list of files uploaded to c:\wamp\sql folder.

Is Visual Studio Community a 30 day trial?

IMPORTANT DISCLAIMER: Information provided below is for educational purposes only! Extending a trial period of Visual Studio Community 2017 might be ILLEGAL!

You have the same effect when You remove all files from HKEY_CLASSES_ROOT\Licenses\5C505A59-E312-4B89-9508-E162F8150517. Run "Visual Studio Installer" and chose option "repair". Now You have new 30 days of trial. But You lost all configuration in Your VS.

Adding machineKey to web.config on web-farm sites

This should answer:

How To: Configure MachineKey in ASP.NET 2.0 - Web Farm Deployment Considerations

Web Farm Deployment Considerations

If you deploy your application in a Web farm, you must ensure that the configuration files on each server share the same value for validationKey and decryptionKey, which are used for hashing and decryption respectively. This is required because you cannot guarantee which server will handle successive requests.

With manually generated key values, the settings should be similar to the following example.

<machineKey  
validationKey="21F090935F6E49C2C797F69BBAAD8402ABD2EE0B667A8B44EA7DD4374267A75D7
               AD972A119482D15A4127461DB1DC347C1A63AE5F1CCFAACFF1B72A7F0A281B"       

decryptionKey="ABAA84D7EC4BB56D75D217CECFFB9628809BDB8BF91CFCD64568A145BE59719F"
validation="SHA1"
decryption="AES"
/>

If you want to isolate your application from other applications on the same server, place the in the Web.config file for each application on each server in the farm. Ensure that you use separate key values for each application, but duplicate each application's keys across all servers in the farm.

In short, to set up the machine key refer the following link: Setting Up a Machine Key - Orchard Documentation.

Setting Up the Machine Key Using IIS Manager

If you have access to the IIS management console for the server where Orchard is installed, it is the easiest way to set-up a machine key.

Start the management console and then select the web site. Open the machine key configuration: The IIS web site configuration panel

The machine key control panel has the following settings:

The machine key configuration panel

Uncheck "Automatically generate at runtime" for both the validation key and the decryption key.

Click "Generate Keys" under "Actions" on the right side of the panel.

Click "Apply".

and add the following line to the web.config file in all the webservers under system.web tag if it does not exist.

<machineKey  
    validationKey="21F0SAMPLEKEY9C2C797F69BBAAD8402ABD2EE0B667A8B44EA7DD4374267A75D7
                   AD972A119482D15A4127461DB1DC347C1A63AE5F1CCFAACFF1B72A7F0A281B"           
    decryptionKey="ABAASAMPLEKEY56D75D217CECFFB9628809BDB8BF91CFCD64568A145BE59719F"
    validation="SHA1"
    decryption="AES"
/>

Please make sure that you have a permanent backup of the machine keys and web.config file

How to import data from one sheet to another

Saw this thread while looking for something else and I know it is super old, but I wanted to add my 2 cents.

NEVER USE VLOOKUP. It's one of the worst performing formulas in excel. Use index match instead. It even works without sorting data, unless you have a -1 or 1 in the end of the match formula (explained more below)

Here is a link with the appropriate formulas.

The Sheet 2 formula would be this: =IF(A2="","",INDEX(Sheet1!B:B,MATCH($A2,Sheet1!$A:$A,0)))

  • IF(A2="","", means if A2 is blank, return a blank value
  • INDEX(Sheet1!B:B, is saying INDEX B:B where B:B is the data you want to return. IE the name column.
  • Match(A2, is saying to Match A2 which is the ID you want to return the Name for.
  • Sheet1!A:A, is saying you want to match A2 to the ID column in the previous sheet
  • ,0)) is specifying you want an exact value. 0 means return an exact match to A2, -1 means return smallest value greater than or equal to A2, 1 means return the largest value that is less than or equal to A2. Keep in mind -1 and 1 have to be sorted.

More information on the Index/Match formula

Other fun facts: $ means absolute in a formula. So if you specify $B$1 when filling a formula down or over keeps that same value. If you over $B1, the B remains the same across the formula, but if you fill down, the 1 increases with the row count. Likewise, if you used B$1, filling to the right will increment the B, but keep the reference of row 1.

I also included the use of indirect in the second section. What indirect does is allow you to use the text of another cell in a formula. Since I created a named range sheet1!A:A = ID, sheet1!B:B = Name, and sheet1!C:C=Price, I can use the column name to have the exact same formula, but it uses the column heading to change the search criteria.

Good luck! Hope this helps.

PHP write file from input to txt

use fwrite() instead of file_put_contents()

How to add elements of a string array to a string array list?

You already have built-in method for that: -

List<String> species = Arrays.asList(speciesArr);

NOTE: - You should use List<String> species not ArrayList<String> species.

Arrays.asList returns a different ArrayList -> java.util.Arrays.ArrayList which cannot be typecasted to java.util.ArrayList.

Then you would have to use addAll method, which is not so good. So just use List<String>

NOTE: - The list returned by Arrays.asList is a fixed size list. If you want to add something to the list, you would need to create another list, and use addAll to add elements to it. So, then you would better go with the 2nd way as below: -

    String[] arr = new String[1];
    arr[0] = "rohit";
    List<String> newList = Arrays.asList(arr);

    // Will throw `UnsupportedOperationException
    // newList.add("jain"); // Can't do this.

    ArrayList<String> updatableList = new ArrayList<String>();

    updatableList.addAll(newList); 

    updatableList.add("jain"); // OK this is fine. 

    System.out.println(newList);       // Prints [rohit]
    System.out.println(updatableList); //Prints [rohit, jain]

How to manage exceptions thrown in filters in Spring?

If you want a generic way, you can define an error page in web.xml:

<error-page>
  <exception-type>java.lang.Throwable</exception-type>
  <location>/500</location>
</error-page>

And add mapping in Spring MVC:

@Controller
public class ErrorController {

    @RequestMapping(value="/500")
    public @ResponseBody String handleException(HttpServletRequest req) {
        // you can get the exception thrown
        Throwable t = (Throwable)req.getAttribute("javax.servlet.error.exception");

        // customize response to what you want
        return "Internal server error.";
    }
}

Possible to view PHP code of a website?

Noone cand read the file except for those who have access to the file. You must make the code readable (but not writable) by the web server. If the php code handler is running properly you can't read it by requesting by name from the web server.

If someone compromises your server you are at risk. Ensure that the web server can only write to locations it absolutely needs to. There are a few locations under /var which should be properly configured by your distribution. They should not be accessible over the web. /var/www should not be writable, but may contain subdirectories written to by the web server for dynamic content. Code handlers should be disabled for these.

Ensure you don't do anything in your php code which can lead to code injection. The other risk is directory traversal using paths containing .. or begining with /. Apache should already be patched to prevent this when it is handling paths. However, when it runs code, including php, it does not control the paths. Avoid anything that allows the web client to pass a file path.

How to open .SQLite files

SQLite is database engine, .sqlite or .db should be a database. If you don't need to program anything, you can use a GUI like sqlitebrowser or anything like that to view the database contents.

There is also spatialite, https://www.gaia-gis.it/fossil/spatialite_gui/index

Dynamic type languages versus static type languages

There are lots of different things about static and dynamic languages. For me, the main difference is that in dynamic languages the variables don't have fixed types; instead, the types are tied to values. Because of this, the exact code that gets executed is undetermined until runtime.

In early or naïve implementations this is a huge performance drag, but modern JITs get tantalizingly close to the best you can get with optimizing static compilers. (in some fringe cases, even better than that).

SSL Error When installing rubygems, Unable to pull data from 'https://rubygems.org/

For Windows Users (and maybe others)

Rubygems.org has a guide that not only explains how to fix this problem, but also why so many people are having it: SSL Certificate Update The reason for the problem is rubygems.org switched to a more secure SSL certificate (SHA-2 which use 256bit encryption). The rubygems command line tool bundles the reference to the correct certificate. Therefore rubygems itself can’t be updated using an older version of rubygems. Rubygems must first be updated manually.

First find out what rubygems you have:

rubygems –v

Depending on whether you have a 1.8.x, 2.0.x or 2.2.x, you will need to download an update gem, named “rubygems-update-X.Y.Z.gem”, where X.Y.Z is the version you need. Running 1.8.x: download: https://github.com/rubygems/rubygems/releases/tag/v1.8.30 Running 2.0.x: download: https://github.com/rubygems/rubygems/releases/tag/v2.0.15 Running 2.2.x: download: https://github.com/rubygems/rubygems/releases/tag/v2.2.3

Install update gem:

gem install –-local full_path_to_the_gem_file

Run update gem:

update_rubygems --no-ri --no-rdoc

Check that rubygems was updated:

rubygems –v

Uninstall update gem:

gem uninstall rubygems-update -x

At this point, you may be OK. But it is possible that you do not have the latest public key file for the new certificate. To do this:

Download the latest certificate, (currently AddTrustExternalCARoot-2048.pem) from https://rubygems.org/pages/download. All of the certs are also located at: https://github.com/rubygems/rubygems/tree/master/lib/rubygems/ssl_certs

Find out where to put it:

gem which rubygems

Put this file in the “rubygems\ssl_certs” directory at this location.

As per rubygems commit, the certificates are moved to more specific directories. Thus, currently the certificate(AddTrustExternalCARoot-2048.pem) is expected to be on the following path lib/rubygems/ssl_certs/rubygems.org/AddTrustExternalCARoot-2048.pem

Adding 'serial' to existing column in Postgres

TL;DR

Here's a version where you don't need a human to read a value and type it out themselves.

CREATE SEQUENCE foo_a_seq OWNED BY foo.a;
SELECT setval('foo_a_seq', coalesce(max(a), 0) + 1, false) FROM foo;
ALTER TABLE foo ALTER COLUMN a SET DEFAULT nextval('foo_a_seq'); 

Another option would be to employ the reusable Function shared at the end of this answer.


A non-interactive solution

Just adding to the other two answers, for those of us who need to have these Sequences created by a non-interactive script, while patching a live-ish DB for instance.

That is, when you don't wanna SELECT the value manually and type it yourself into a subsequent CREATE statement.

In short, you can not do:

CREATE SEQUENCE foo_a_seq
    START WITH ( SELECT max(a) + 1 FROM foo );

... since the START [WITH] clause in CREATE SEQUENCE expects a value, not a subquery.

Note: As a rule of thumb, that applies to all non-CRUD (i.e.: anything other than INSERT, SELECT, UPDATE, DELETE) statements in pgSQL AFAIK.

However, setval() does! Thus, the following is absolutely fine:

SELECT setval('foo_a_seq', max(a)) FROM foo;

If there's no data and you don't (want to) know about it, use coalesce() to set the default value:

SELECT setval('foo_a_seq', coalesce(max(a), 0)) FROM foo;
--                         ^      ^         ^
--                       defaults to:       0

However, having the current sequence value set to 0 is clumsy, if not illegal.
Using the three-parameter form of setval would be more appropriate:

--                                             vvv
SELECT setval('foo_a_seq', coalesce(max(a), 0) + 1, false) FROM foo;
--                                                  ^   ^
--                                                is_called

Setting the optional third parameter of setval to false will prevent the next nextval from advancing the sequence before returning a value, and thus:

the next nextval will return exactly the specified value, and sequence advancement commences with the following nextval.

— from this entry in the documentation

On an unrelated note, you also can specify the column owning the Sequence directly with CREATE, you don't have to alter it later:

CREATE SEQUENCE foo_a_seq OWNED BY foo.a;

In summary:

CREATE SEQUENCE foo_a_seq OWNED BY foo.a;
SELECT setval('foo_a_seq', coalesce(max(a), 0) + 1, false) FROM foo;
ALTER TABLE foo ALTER COLUMN a SET DEFAULT nextval('foo_a_seq'); 

Using a Function

Alternatively, if you're planning on doing this for multiple columns, you could opt for using an actual Function.

CREATE OR REPLACE FUNCTION make_into_serial(table_name TEXT, column_name TEXT) RETURNS INTEGER AS $$
DECLARE
    start_with INTEGER;
    sequence_name TEXT;
BEGIN
    sequence_name := table_name || '_' || column_name || '_seq';
    EXECUTE 'SELECT coalesce(max(' || column_name || '), 0) + 1 FROM ' || table_name
            INTO start_with;
    EXECUTE 'CREATE SEQUENCE ' || sequence_name ||
            ' START WITH ' || start_with ||
            ' OWNED BY ' || table_name || '.' || column_name;
    EXECUTE 'ALTER TABLE ' || table_name || ' ALTER COLUMN ' || column_name ||
            ' SET DEFAULT nextVal(''' || sequence_name || ''')';
    RETURN start_with;
END;
$$ LANGUAGE plpgsql VOLATILE;

Use it like so:

INSERT INTO foo (data) VALUES ('asdf');
-- ERROR: null value in column "a" violates not-null constraint

SELECT make_into_serial('foo', 'a');
INSERT INTO foo (data) VALUES ('asdf');
-- OK: 1 row(s) affected

Modify property value of the objects in list using Java 8 streams

You can use just forEach. No stream at all:

fruits.forEach(fruit -> fruit.setName(fruit.getName() + "s"));

Creating an iframe with given HTML dynamically

I know this is an old question but I thought I would provide an example using the srcdoc attribute as this is now widely supported and this is question is viewed often.

Using the srcdoc attribute, you can provide inline HTML to embed. It overrides the src attribute if supported. The browser will fall back to the src attribute if unsupported.

I would also recommend using the sandbox attribute to apply extra restrictions to the content in the frame. This is especially important if the HTML is not your own.

_x000D_
_x000D_
const iframe = document.createElement('iframe');_x000D_
const html = '<body>Foo</body>';_x000D_
iframe.srcdoc = html;_x000D_
iframe.sandbox = '';_x000D_
document.body.appendChild(iframe);
_x000D_
_x000D_
_x000D_

If you need to support older browsers, you can check for srcdoc support and fallback to one of the other methods from other answers.

_x000D_
_x000D_
function setIframeHTML(iframe, html) {_x000D_
  if (typeof iframe.srcdoc !== 'undefined') {_x000D_
    iframe.srcdoc = html;_x000D_
  } else {_x000D_
    iframe.sandbox = 'allow-same-origin';_x000D_
    iframe.contentWindow.document.open();_x000D_
    iframe.contentWindow.document.write(html);_x000D_
    iframe.contentWindow.document.close();_x000D_
  }_x000D_
}_x000D_
_x000D_
var iframe = document.createElement('iframe');_x000D_
iframe.sandbox = '';_x000D_
var html = '<body>Foo</body>';_x000D_
_x000D_
document.body.appendChild(iframe);_x000D_
setIframeHTML(iframe, html);
_x000D_
_x000D_
_x000D_

How to set a hidden value in Razor

While I would have gone with Piotr's answer (because it's all in one line), I was surprised that your sample is closer to your solution than you think. From what you have, you simply assign the model value before you use the Html helper method.

@{Model.RequiredProperty = "default";}
@Html.HiddenFor(model => model.RequiredProperty)

Viewing unpushed Git commits

git branch -v will show, for each local branch, whether it's "ahead" or not.

How do you enable auto-complete functionality in Visual Studio C++ express edition?

I came across over the following post: http://blogs.msdn.com/b/raulperez/archive/2010/03/19/c-intellisense-options.aspx

The issue is that the "IntelliSense" option in c++ is disabled. This link explains about the IntelliSense database configuration and options.

After enabling the database you must close and reopen visual studio for autocomplete use 'ctrl'+'space'

eval command in Bash and its typical uses

I like the "evaluating your expression one additional time before execution" answer, and would like to clarify with another example.

var="\"par1 par2\""
echo $var # prints nicely "par1 par2"

function cntpars() {
  echo "  > Count: $#"
  echo "  > Pars : $*"
  echo "  > par1 : $1"
  echo "  > par2 : $2"

  if [[ $# = 1 && $1 = "par1 par2" ]]; then
    echo "  > PASS"
  else
    echo "  > FAIL"
    return 1
  fi
}

# Option 1: Will Pass
echo "eval \"cntpars \$var\""
eval "cntpars $var"

# Option 2: Will Fail, with curious results
echo "cntpars \$var"
cntpars $var

The Curious results in Option 2 are that we would have passed 2 parameters as follows:

  • First Parameter: "value
  • Second Parameter: content"

How is that for counter intuitive? The additional eval will fix that.

Adapted from https://stackoverflow.com/a/40646371/744133

Combination of async function + await + setTimeout

Update 2020

You can await setTimeout with Node.js 15 or above:

const timersPromises = require('timers/promises');

(async () => {
  const result = await timersPromises.setTimeout(2000, 'resolved')
  // Executed after 2 seconds
  console.log(result); // "resolved"
})()

Timers Promises API: https://nodejs.org/api/timers.html#timers_timers_promises_api (library already built in Node)


Note: Stability: 1 - Use of the feature is not recommended in production environments.

What is the native keyword in Java for?

functions that implement native code are declared native.

The Java Native Interface (JNI) is a programming framework that enables Java code running in a Java Virtual Machine (JVM) to call, and to be called by, native applications (programs specific to a hardware and operating system platform) and libraries written in other languages such as C, C++ and assembly.

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

Is there a way I can retrieve sa password in sql server 2005

There is no way to get the old password back. Log into the SQL server management console as a machine or domain admin using integrated authentication, you can then change any password (including sa).

Start the SQL service again and use the new created login (recovery in my example) Go via the security panel to the properties and change the password of the SA account.

enter image description here

Now write down the new SA password.

Can I do a max(count(*)) in SQL?

     select top 1 yr,count(*)  from movie
join casting on casting.movieid=movie.id
join actor on casting.actorid = actor.id
where actor.name = 'John Travolta'
group by yr order by 2 desc

How to debug Apache mod_rewrite

There's the htaccess tester.

It shows which conditions were tested for a certain URL, which ones met the criteria and which rules got executed.

It seems to have some glitches, though.

_DEBUG vs NDEBUG

Unfortunately DEBUG is overloaded heavily. For instance, it's recommended to always generate and save a pdb file for RELEASE builds. Which means one of the -Zx flags, and -DEBUG linker option. While _DEBUG relates to special debug versions of runtime library such as calls to malloc and free. Then NDEBUG will disable assertions.

Catch multiple exceptions in one line (except block)

From Python documentation -> 8.3 Handling Exceptions:

A try statement may have more than one except clause, to specify handlers for different exceptions. At most one handler will be executed. Handlers only handle exceptions that occur in the corresponding try clause, not in other handlers of the same try statement. An except clause may name multiple exceptions as a parenthesized tuple, for example:

except (RuntimeError, TypeError, NameError):
    pass

Note that the parentheses around this tuple are required, because except ValueError, e: was the syntax used for what is normally written as except ValueError as e: in modern Python (described below). The old syntax is still supported for backwards compatibility. This means except RuntimeError, TypeError is not equivalent to except (RuntimeError, TypeError): but to except RuntimeError as TypeError: which is not what you want.

Why is my variable unaltered after I modify it inside of a function? - Asynchronous code reference

In all these scenarios outerScopeVar is modified or assigned a value asynchronously or happening in a later time(waiting or listening for some event to occur),for which the current execution will not wait.So all these cases current execution flow results in outerScopeVar = undefined

Let's discuss each examples(I marked the portion which is called asynchronously or delayed for some events to occur):

1.

enter image description here

Here we register an eventlistner which will be executed upon that particular event.Here loading of image.Then the current execution continuous with next lines img.src = 'lolcat.png'; and alert(outerScopeVar); meanwhile the event may not occur. i.e, funtion img.onload wait for the referred image to load, asynchrously. This will happen all the folowing example- the event may differ.

2.

2

Here the timeout event plays the role, which will invoke the handler after the specified time. Here it is 0, but still it registers an asynchronous event it will be added to the last position of the Event Queue for execution, which makes the guaranteed delay.

3.

enter image description here This time ajax callback.

4.

enter image description here

Node can be consider as a king of asynchronous coding.Here the marked function is registered as a callback handler which will be executed after reading the specified file.

5.

enter image description here

Obvious promise (something will be done in future) is asynchronous. see What are the differences between Deferred, Promise and Future in JavaScript?

https://www.quora.com/Whats-the-difference-between-a-promise-and-a-callback-in-Javascript

How to fix '.' is not an internal or external command error

Just leave out the "dot-slash" ./:

D:\Gesture Recognition\Gesture Recognition\Debug>"Gesture Recognition.exe"

Though, if you wanted to, you could use .\ and it would work.

D:\Gesture Recognition\Gesture Recognition\Debug>.\"Gesture Recognition.exe"

Commit empty folder structure (with git)

Simply add file named as .keep in images folder.you can now stage and commit and also able to add folder to version control.

Create a empty file in images folder $ touch .keep

$ git status

On branch master
Your branch is up-to-date with 'origin/master'.

Untracked files:
  (use "git add ..." to include in what will be committed)

    images/

nothing added to commit but untracked files present (use "git add" to track)

$ git add .

$ git commit -m "adding empty folder"

Checking to see if one array's elements are in another array in PHP

You can use array_intersect().

$result = !empty(array_intersect($people, $criminals));

SyntaxError: expected expression, got '<'

I had this same error when I migrated a Wordpress site to another server. The URL in the header for my js scripts was still pointing to the old server and domain name.

Once I updated the domain name, the error went away.

When and how should I use a ThreadLocal variable?

As was mentioned by @unknown (google), it's usage is to define a global variable in which the value referenced can be unique in each thread. It's usages typically entails storing some sort of contextual information that is linked to the current thread of execution.

We use it in a Java EE environment to pass user identity to classes that are not Java EE aware (don't have access to HttpSession, or the EJB SessionContext). This way the code, which makes usage of identity for security based operations, can access the identity from anywhere, without having to explicitly pass it in every method call.

The request/response cycle of operations in most Java EE calls makes this type of usage easy since it gives well defined entry and exit points to set and unset the ThreadLocal.

JSON find in JavaScript

Zapping - you can use this javascript lib; DefiantJS. There is no need to restructure JSON data into objects to ease searching. Instead, you can search the JSON structure with an XPath expression like this:

    var data = [
   {
      "id": "one",
      "pId": "foo1",
      "cId": "bar1"
   },
   {
      "id": "two",
      "pId": "foo2",
      "cId": "bar2"
   },
   {
      "id": "three",
      "pId": "foo3",
      "cId": "bar3"
   }
],
res = JSON.search( data, '//*[id="one"]' );

console.log( res[0].cId );
// 'bar1'

DefiantJS extends the global object JSON with a new method; "search" which returns array with the matches (empty array if none were found). You can try it out yourself by pasting your JSON data and testing different XPath queries here:

http://www.defiantjs.com/#xpath_evaluator

XPath is, as you know, a standardised query language.

How do I decrease the size of my sql server log file?

Welcome to the fickle world of SQL Server log management.

SOMETHING is wrong, though I don't think anyone will be able to tell you more than that without some additional information. For example, has this database ever been used for Transactional SQL Server replication? This can cause issues like this if a transaction hasn't been replicated to a subscriber.

In the interim, this should at least allow you to kill the log file:

  1. Perform a full backup of your database. Don't skip this. Really.
  2. Change the backup method of your database to "Simple"
  3. Open a query window and enter "checkpoint" and execute
  4. Perform another backup of the database
  5. Change the backup method of your database back to "Full" (or whatever it was, if it wasn't already Simple)
  6. Perform a final full backup of the database.

You should now be able to shrink the files (if performing the backup didn't do that for you).

Good luck!

MySQL server has gone away - in exactly 60 seconds

By my experiences when it happens on light queries there is a way to solve the problem. It seems when you start or restart mysql after apache this problem starts to appear and the source of the problem is confused open sockets in the php process. To solve it:

  1. First restart mysql service

  2. Then restart apache service

How to find the privileges and roles granted to a user in Oracle?

The only visible result I was able to understand was first to connect with the user I wanted to get the rights, then with the following query:

SELECT GRANTEE, PRIVILEGE, TABLE_NAME FROM USER_TAB_PRIVS;

Extracting .jar file with command line

In Ubuntu:

unzip file.jar -d dir_name_where_extracting

How to decode jwt token in javascript without using a library?

Answer based from GitHub - auth0/jwt-decode. Altered the input/output to include string splitting and return object { header, payload, signature } so you can just pass the whole token.

var jwtDecode = function (jwt) {

        function b64DecodeUnicode(str) {
            return decodeURIComponent(atob(str).replace(/(.)/g, function (m, p) {
                var code = p.charCodeAt(0).toString(16).toUpperCase();
                if (code.length < 2) {
                    code = '0' + code;
                }
                return '%' + code;
            }));
        }

        function decode(str) {
            var output = str.replace(/-/g, "+").replace(/_/g, "/");
            switch (output.length % 4) {
                case 0:
                    break;
                case 2:
                    output += "==";
                    break;
                case 3:
                    output += "=";
                    break;
                default:
                    throw "Illegal base64url string!";
            }

            try {
                return b64DecodeUnicode(output);
            } catch (err) {
                return atob(output);
            }
        }

        var jwtArray = jwt.split('.');

        return {
            header: decode(jwtArray[0]),
            payload: decode(jwtArray[1]),
            signature: decode(jwtArray[2])
        };

    };

Converting a value to 2 decimal places within jQuery

You need to use the .toFixed() method

It takes as a parameter the number of digits to show after the decimal point.

$(document).ready(function() {
  $('.add').click(function() {
     var value = parseFloat($('#total').text()) + parseFloat($(this).data('amount'))/100
     $('#total').text( value.toFixed(2) );
  });
})

How to set border's thickness in percentages?

Box Sizing
set the box sizing to border box box-sizing: border-box; and set the width to 100% and a fixed width for the border then add a min-width so for a small screen the border won't overtake the whole screen

How do I see which checkbox is checked?

you can check that by either isset() or empty() (its check explicit isset) weather check box is checked or not

for example

  <input type='checkbox' name='Mary' value='2' id='checkbox' />

here you can check by

if (isset($_POST['Mary'])) {
    echo "checked!";
}

or

if (!empty($_POST['Mary'])) {
    echo "checked!";
}

the above will check only one if you want to do for many than you can make an array instead writing separate for all checkbox try like

<input type="checkbox" name="formDoor[]" value="A" />Acorn Building<br />
<input type="checkbox" name="formDoor[]" value="B" />Brown Hall<br />
<input type="checkbox" name="formDoor[]" value="C" />Carnegie Complex<br />

php

  $aDoor = $_POST['formDoor'];
  if(empty($aDoor))
  {
    echo("You didn't select any buildings.");
  }
  else
  {
    $N = count($aDoor);
    echo("You selected $N door(s): ");
    for($i=0; $i < $N; $i++)
    {
      echo htmlspecialchars($aDoor[$i] ). " ";
    }
  }

Run AVD Emulator without Android Studio

In the ANDROID_HOME folder you will have tools folder

In Mac/Linux emulator -avd <avdName> In Windows emulator.exe -avd <avdName>

If you are using API 24 You can get the names of the emulator from the list android list avds If you are using API 25 then you will get it with avdmanager in tools\bin avdmanager list avds

Error: unmappable character for encoding UTF8 during maven compilation

Configure the maven-compiler-plugin to use the same character encoding that your source files are encoded in (e.g):

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>2.3.2</version>
    <configuration>
        <source>1.6</source>
        <target>1.6</target>
        <encoding>UTF-8</encoding>
    </configuration>
</plugin>

Many maven plugins will by default use the "project.build.sourceEncoding" property so setting this in your pom will cover most plugins.

<project>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
...

However, I prefer setting the encoding in each plugin's configuration that supports it as I like to be explicit.

When your source code is compiled by the maven-compiler-plugin your source code files are read in by the compiler plugin using whatever encoding the compiler plugin is configured with. If your source files have a different encoding than the compiler plugin is using then it is possible that some characters may not exist in both encodings.

Many people prefer to set the encoding on their source files to UTF-8 so as to avoid this problem. To do this in Eclipse you can right click on a project and select Properties->Resource->Text File Encoding and change it to UTF-8. This will encode all your source files in UTF-8. (You should also explicitly configure the maven-compiler-plugin as mentioned above to use UTF-8 encoding.) With your source files and the compiler plugin both using the same encoding you shouldn't have any more unmappable characters during compilation.

Note, You can also set the file encoding globally in eclipse through Window->Preferences->General->Workspace->Text File Encoding. You can also set the encoding per file type through Window->Preferences->General->Content Types.

How to get row index number in R?

If i understand your question, you just want to be able to access items in a data frame (or list) by row:

x = matrix( ceiling(9*runif(20)), nrow=5  )   
colnames(x) = c("col1", "col2", "col3", "col4")
df = data.frame(x)      # create a small data frame

df[1,]                  # get the first row
df[3,]                  # get the third row
df[nrow(df),]           # get the last row

lf = as.list(df)        

lf[[1]]                 # get first row
lf[[3]]                 # get third row

etc.

ISO C++ forbids comparison between pointer and integer [-fpermissive]| [c++]

char a[2] defines an array of char's. a is a pointer to the memory at the beginning of the array and using == won't actually compare the contents of a with 'ab' because they aren't actually the same types, 'ab' is integer type. Also 'ab' should be "ab" otherwise you'll have problems here too. To compare arrays of char you'd want to use strcmp.

Something that might be illustrative is looking at the typeid of 'ab':

#include <iostream>
#include <typeinfo>
using namespace std;
int main(){
    int some_int =5;
    std::cout << typeid('ab').name() << std::endl;
    std::cout << typeid(some_int).name() << std::endl;
    return 0;
}

on my system this returns:

i
i

showing that 'ab' is actually evaluated as an int.

If you were to do the same thing with a std::string then you would be dealing with a class and std::string has operator == overloaded and will do a comparison check when called this way.

If you wish to compare the input with the string "ab" in an idiomatic c++ way I suggest you do it like so:

#include <iostream>
#include <string>
using namespace std;
int main(){
    string a;
    cout<<"enter ab ";
    cin>>a;
    if(a=="ab"){
         cout<<"correct";
    }
    return 0;
}

This one is due to:

if(a=='ab') , here, a is const char* type (ie : array of char)

'ab' is a constant value,which isn't evaluated as string (because of single quote) but will be evaluated as integer.

Since char is a primitive type inherited from C, no operator == is defined.

the good code should be:

if(strcmp(a,"ab")==0) , then you'll compare a const char* to another const char* using strcmp.

Finding duplicate values in a SQL table

SELECT
    name, email, COUNT(*)
FROM
    users
GROUP BY
    name, email
HAVING 
    COUNT(*) > 1

Simply group on both of the columns.

Note: the older ANSI standard is to have all non-aggregated columns in the GROUP BY but this has changed with the idea of "functional dependency":

In relational database theory, a functional dependency is a constraint between two sets of attributes in a relation from a database. In other words, functional dependency is a constraint that describes the relationship between attributes in a relation.

Support is not consistent:

Redirecting output to $null in PowerShell, but ensuring the variable remains set

I'd prefer this way to redirect standard output (native PowerShell)...

($foo = someFunction) | out-null

But this works too:

($foo = someFunction) > $null

To redirect just standard error after defining $foo with result of "someFunction", do

($foo = someFunction) 2> $null

This is effectively the same as mentioned above.

Or to redirect any standard error messages from "someFunction" and then defining $foo with the result:

$foo = (someFunction 2> $null)

To redirect both you have a few options:

2>&1>$null
2>&1 | out-null

Aligning label and textbox on same line (left and right)

You can do it with a table, like this:

<table width="100%">
  <tr>
    <td style="width: 50%">Left Text</td>
    <td style="width: 50%; text-align: right;">Right Text</td>
  </tr>
</table>

Or, you can do it with CSS like this:

<div style="float: left;">
    Left text
</div>
<div style="float: right;">
    Right text
</div>

Create text file and fill it using bash

Your question is a a bit vague. This is a shell command that does what I think you want to do:

echo >> name_of_file

JavaScript before leaving the page

Normally you want to show this message, when the user has made changes in a form, but they are not saved.

Take this approach to show a message, only when the user has changed something

var form = $('#your-form'),
  original = form.serialize()

form.submit(function(){
  window.onbeforeunload = null
})

window.onbeforeunload = function(){
  if (form.serialize() != original)
    return 'Are you sure you want to leave?'
}

Python re.sub replace with matched content

Use \1 instead of $1.

\number Matches the contents of the group of the same number.

http://docs.python.org/library/re.html#regular-expression-syntax

How do I set a path in Visual Studio?

Search MSDN for "How to: Set Environment Variables for Projects". (It's Project>Properties>Configuration Properties>Debugging "Environment" and "Merge Environment" properties for those who are in a rush.)

The syntax is NAME=VALUE and macros can be used (for example, $(OutDir)).

For example, to prepend C:\Windows\Temp to the PATH:

PATH=C:\WINDOWS\Temp;%PATH%

Similarly, to append $(TargetDir)\DLLS to the PATH:

PATH=%PATH%;$(TargetDir)\DLLS

Valid characters in a Java class name

You can have almost any character, including most Unicode characters! The exact definition is in the Java Language Specification under section 3.8: Identifiers.

An identifier is an unlimited-length sequence of Java letters and Java digits, the first of which must be a Java letter. ...

Letters and digits may be drawn from the entire Unicode character set, ... This allows programmers to use identifiers in their programs that are written in their native languages.

An identifier cannot have the same spelling (Unicode character sequence) as a keyword (§3.9), boolean literal (§3.10.3), or the null literal (§3.10.7), or a compile-time error occurs.

However, see this question for whether or not you should do that.

How do I run PHP code when a user clicks on a link?

Well you said without redirecting. Well its a javascript code:

<a href="JavaScript:void(0);" onclick="function()">Whatever!</a>

<script type="text/javascript">
function confirm_delete() {
    var delete_confirmed=confirm("Are you sure you want to delete this file?");

    if (delete_confirmed==true) {
       // the php code :) can't expose mine ^_^
    } else { 
       // this one returns the user if he/she clicks no :)
       document.location.href = 'whatever.php';
    }
}
</script>

give it a try :) hope you like it

Calculate average in java

for 1. the number of integers read in, you can just use length property of array like :

int count = args.length

which gives you no of elements in an array. And 2. to calculate average value : you are doing in correct way.

Enabling HTTPS on express.js

This is my working code for express 4.0.

express 4.0 is very different from 3.0 and others.

4.0 you have /bin/www file, which you are going to add https here.

"npm start" is standard way you start express 4.0 server.

readFileSync() function should use __dirname get current directory

while require() use ./ refer to current directory.

First you put private.key and public.cert file under /bin folder, It is same folder as WWW file.

C# 'or' operator?

C# supports two boolean or operators: the single bar | and the double-bar ||.

The difference is that | always checks both the left and right conditions, while || only checks the right-side condition if it's necessary (if the left side evaluates to false).

This is significant when the condition on the right-side involves processing or results in side effects. (For example, if your ErrorDumpWriter.Close method took a while to complete or changed something's state.)

What's the difference between 'git merge' and 'git rebase'?

Git rebase is closer to a merge. The difference in rebase is:

  • the local commits are removed temporally from the branch.
  • run the git pull
  • insert again all your local commits.

So that means that all your local commits are moved to the end, after all the remote commits. If you have a merge conflict, you have to solve it too.

Asynchronous Requests with Python requests

If you want to use asyncio, then requests-async provides async/await functionality for requests - https://github.com/encode/requests-async

How does the compilation/linking process work?

The compilation of a C++ program involves three steps:

  1. Preprocessing: the preprocessor takes a C++ source code file and deals with the #includes, #defines and other preprocessor directives. The output of this step is a "pure" C++ file without pre-processor directives.

  2. Compilation: the compiler takes the pre-processor's output and produces an object file from it.

  3. Linking: the linker takes the object files produced by the compiler and produces either a library or an executable file.

Preprocessing

The preprocessor handles the preprocessor directives, like #include and #define. It is agnostic of the syntax of C++, which is why it must be used with care.

It works on one C++ source file at a time by replacing #include directives with the content of the respective files (which is usually just declarations), doing replacement of macros (#define), and selecting different portions of text depending of #if, #ifdef and #ifndef directives.

The preprocessor works on a stream of preprocessing tokens. Macro substitution is defined as replacing tokens with other tokens (the operator ## enables merging two tokens when it makes sense).

After all this, the preprocessor produces a single output that is a stream of tokens resulting from the transformations described above. It also adds some special markers that tell the compiler where each line came from so that it can use those to produce sensible error messages.

Some errors can be produced at this stage with clever use of the #if and #error directives.

Compilation

The compilation step is performed on each output of the preprocessor. The compiler parses the pure C++ source code (now without any preprocessor directives) and converts it into assembly code. Then invokes underlying back-end(assembler in toolchain) that assembles that code into machine code producing actual binary file in some format(ELF, COFF, a.out, ...). This object file contains the compiled code (in binary form) of the symbols defined in the input. Symbols in object files are referred to by name.

Object files can refer to symbols that are not defined. This is the case when you use a declaration, and don't provide a definition for it. The compiler doesn't mind this, and will happily produce the object file as long as the source code is well-formed.

Compilers usually let you stop compilation at this point. This is very useful because with it you can compile each source code file separately. The advantage this provides is that you don't need to recompile everything if you only change a single file.

The produced object files can be put in special archives called static libraries, for easier reusing later on.

It's at this stage that "regular" compiler errors, like syntax errors or failed overload resolution errors, are reported.

Linking

The linker is what produces the final compilation output from the object files the compiler produced. This output can be either a shared (or dynamic) library (and while the name is similar, they haven't got much in common with static libraries mentioned earlier) or an executable.

It links all the object files by replacing the references to undefined symbols with the correct addresses. Each of these symbols can be defined in other object files or in libraries. If they are defined in libraries other than the standard library, you need to tell the linker about them.

At this stage the most common errors are missing definitions or duplicate definitions. The former means that either the definitions don't exist (i.e. they are not written), or that the object files or libraries where they reside were not given to the linker. The latter is obvious: the same symbol was defined in two different object files or libraries.

VBA test if cell is in a range

If the two ranges to be tested (your given cell and your given range) are not in the same Worksheet, then Application.Intersect throws an error. Thus, a way to avoid it is with something like

Sub test_inters(rng1 As Range, rng2 As Range)
    If (rng1.Parent.Name = rng2.Parent.Name) Then
        Dim ints As Range
        Set ints = Application.Intersect(rng1, rng2)
        If (Not (ints Is Nothing)) Then
            ' Do your job
        End If
    End If
End Sub

How to do integer division in javascript (Getting division answer in int not float)?

var x = parseInt(455/10);

The parseInt() function parses a string and returns an integer.

The radix parameter is used to specify which numeral system to be used, for example, a radix of 16 (hexadecimal) indicates that the number in the string should be parsed from a hexadecimal number to a decimal number.

If the radix parameter is omitted, JavaScript assumes the following:

If the string begins with "0x", the radix is 16 (hexadecimal)
If the string begins with "0", the radix is 8 (octal). This feature is deprecated
If the string begins with any other value, the radix is 10 (decimal)

How to check variable type at runtime in Go language

What's wrong with

func (e *Easy)SetStringOption(option Option, param string)
func (e *Easy)SetLongOption(option Option, param long)

and so on?

Can I call a function of a shell script from another shell script?

You can't directly call a function in another shell script.

You can move your function definitions into a separate file and then load them into your script using the . command, like this:

. /path/to/functions.sh

This will interpret functions.sh as if it's content were actually present in your file at this point. This is a common mechanism for implementing shared libraries of shell functions.

What can cause a “Resource temporarily unavailable” on sock send() command

Let'e me give an example:

  1. client connect to server, and send 1MB data to server every 1 second.

  2. server side accept a connection, and then sleep 20 second, without recv msg from client.So the tcp send buffer in the client side will be full.

Code in client side:

#include <arpa/inet.h>
#include <sys/socket.h>
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#define exit_if(r, ...)                                                                          \
    if (r) {                                                                                     \
        printf(__VA_ARGS__);                                                                     \
        printf("%s:%d error no: %d error msg %s\n", __FILE__, __LINE__, errno, strerror(errno)); \
        exit(1);                                                                                 \
    }

void setNonBlock(int fd) {
    int flags = fcntl(fd, F_GETFL, 0);
    exit_if(flags < 0, "fcntl failed");
    int r = fcntl(fd, F_SETFL, flags | O_NONBLOCK);
    exit_if(r < 0, "fcntl failed");
}

void test_full_sock_buf_1(){
    short port = 8000;
    struct sockaddr_in addr;
    memset(&addr, 0, sizeof addr);
    addr.sin_family = AF_INET;
    addr.sin_port = htons(port);
    addr.sin_addr.s_addr = INADDR_ANY;


    int fd = socket(AF_INET, SOCK_STREAM, 0);
    exit_if(fd<0, "create socket error");

    int ret = connect(fd, (struct sockaddr *) &addr, sizeof(struct sockaddr));
    exit_if(ret<0, "connect to server error");
    setNonBlock(fd);

    printf("connect to server success");

    const int LEN = 1024 * 1000;
    char msg[LEN];  // 1MB data
    memset(msg, 'a', LEN);

    for (int i = 0; i < 1000; ++i) {
        int len = send(fd, msg, LEN, 0);
        printf("send: %d, erron: %d, %s \n", len, errno, strerror(errno));
        sleep(1);
    }

}

int main(){
    test_full_sock_buf_1();

    return 0;
}

Code in server side:

    #include <arpa/inet.h>
    #include <sys/socket.h>
    #include <stdio.h>
    #include <errno.h>
    #include <fcntl.h>
    #include <stdlib.h>
    #include <string.h>
    #define exit_if(r, ...)                                                                          \
        if (r) {                                                                                     \
            printf(__VA_ARGS__);                                                                     \
            printf("%s:%d error no: %d error msg %s\n", __FILE__, __LINE__, errno, strerror(errno)); \
            exit(1);                                                                                 \
        }
void test_full_sock_buf_1(){

    int listenfd = socket(AF_INET, SOCK_STREAM, 0);
    exit_if(listenfd<0, "create socket error");

    short port = 8000;
    struct sockaddr_in addr;
    memset(&addr, 0, sizeof addr);
    addr.sin_family = AF_INET;
    addr.sin_port = htons(port);
    addr.sin_addr.s_addr = INADDR_ANY;

    int r = ::bind(listenfd, (struct sockaddr *) &addr, sizeof(struct sockaddr));
    exit_if(r<0, "bind socket error");

    r = listen(listenfd, 100);
    exit_if(r<0, "listen socket error");

    struct sockaddr_in raddr;
    socklen_t rsz = sizeof(raddr);
    int cfd = accept(listenfd, (struct sockaddr *) &raddr, &rsz);
    exit_if(cfd<0, "accept socket error");

    sockaddr_in peer;
    socklen_t alen = sizeof(peer);
    getpeername(cfd, (sockaddr *) &peer, &alen);

    printf("accept a connection from %s:%d\n", inet_ntoa(peer.sin_addr), ntohs(peer.sin_port));

    printf("but now I will sleep 15 second, then exit");
    sleep(15);
}

Start server side, then start client side.

server side may output:

accept a connection from 127.0.0.1:35764
but now I will sleep 15 second, then exit
Process finished with exit code 0

enter image description here

client side may output:

connect to server successsend: 1024000, erron: 0, Success 
send: 1024000, erron: 0, Success 
send: 1024000, erron: 0, Success 
send: 552190, erron: 0, Success 
send: -1, erron: 11, Resource temporarily unavailable 
send: -1, erron: 11, Resource temporarily unavailable 
send: -1, erron: 11, Resource temporarily unavailable 
send: -1, erron: 11, Resource temporarily unavailable 
send: -1, erron: 11, Resource temporarily unavailable 
send: -1, erron: 11, Resource temporarily unavailable 
send: -1, erron: 11, Resource temporarily unavailable 
send: -1, erron: 11, Resource temporarily unavailable 
send: -1, erron: 11, Resource temporarily unavailable 
send: -1, erron: 11, Resource temporarily unavailable 
send: -1, erron: 11, Resource temporarily unavailable 
send: -1, erron: 104, Connection reset by peer 
send: -1, erron: 32, Broken pipe 
send: -1, erron: 32, Broken pipe 
send: -1, erron: 32, Broken pipe 
send: -1, erron: 32, Broken pipe 
send: -1, erron: 32, Broken pipe 

enter image description here

You can see, as the server side doesn't recv the data from client, so when the client side tcp buffer get full, but you still send data, so you may get Resource temporarily unavailable error.

I have filtered my Excel data and now I want to number the rows. How do I do that?

I had the same need to fill up a column with a sequence series for each value on another column. I tried all the answers above and could not fix the problem. I solved it with a simple VBA macro.

My data have the same structure (but with 3000 rows):

  • N2 is the column on which the table is filtered;
  • N3 is the column where I wanted to fill a series;

A | B

N2 | N3

1 | 1

2 | 1

3 | 1

1 | 2

6 | 1

4 | 1

2 | 2

1 | 3

5 | 1

Here below the code:

> Sub Seq_N3() ' ' Seq_N3 Macro ' Sequence numbering of N3 based on N2 value
> do N2 
>     Dim N2 As Integer
>     Dim seq As Integer
> 
>         With ActiveSheet
>             
>             For N2 = 1 To 7 Step 1
>             seq = 1                 ' 
>             .Range("B2").Select     ' 
>             
>                 Do While ActiveCell.Offset(0, -1).Value2 <> 0
>                     
>                     If ActiveCell.Offset(0, -1).Value2 = N2 Then        
>                         ActiveCell.Value2 = seq                         
>                         seq = seq + 1                                   
>                         ActiveCell.Offset(1, 0).Select
>                     Else
>                         ActiveCell.Offset(1, 0).Select                  
>                     End If
>                     
>                 Loop
>                 
>             Next N2
>                    
>         End With End Sub

Hope it helps!

How to remove the last element added into the List?

You can use List<T>.RemoveAt method:

rows.RemoveAt(rows.Count -1);

Javascript return number of days,hours,minutes,seconds between two dates

Here is a code example. I used simple calculations instead of using precalculations like 1 day is 86400 seconds. So you can follow the logic with ease.

// Calculate time between two dates:
var date1 = new Date('1110-01-01 11:10');
var date2 = new Date();

console.log('difference in ms', date1 - date2);

// Use Math.abs() so the order of the dates can be ignored and you won't
// end up with negative numbers when date1 is before date2.
console.log('difference in ms abs', Math.abs(date1 - date2));
console.log('difference in seconds', Math.abs(date1 - date2) / 1000);

var diffInSeconds = Math.abs(date1 - date2) / 1000;
var days = Math.floor(diffInSeconds / 60 / 60 / 24);
var hours = Math.floor(diffInSeconds / 60 / 60 % 24);
var minutes = Math.floor(diffInSeconds / 60 % 60);
var seconds = Math.floor(diffInSeconds % 60);
var milliseconds = Math.round((diffInSeconds - Math.floor(diffInSeconds)) * 1000);

console.log('days', days);
console.log('hours', ('0' + hours).slice(-2));
console.log('minutes', ('0' + minutes).slice(-2));
console.log('seconds', ('0' + seconds).slice(-2));
console.log('milliseconds', ('00' + milliseconds).slice(-3));

How do I resolve a TesseractNotFoundError?

For Mac:

  1. Install Pytesseract (pip install pytesseract should work)
  2. Install Tesseract but only with homebrew, pip installation somehow doesn't work. (brew install tesseract)
  3. Get the path of brew installation of Tesseract on your device (brew list tesseract)
  4. Add the path into your code, not in sys path. The path is to be added along with code, using pytesseract.pytesseract.tesseract_cmd = '<path received in step 3>' - (e.g. pytesseract.pytesseract.tesseract_cmd = '/usr/local/Cellar/tesseract/4.0.0_1/bin/tesseract')

This should work fine.

How to get input text value on click in ReactJS

There are two ways to go about doing this.

  1. Create a state in the constructor that contains the text input. Attach an onChange event to the input box that updates state each time. Then onClick you could just alert the state object.

  2. handleClick: function() { alert(this.refs.myInput.value); },

Compare two Lists for differences

.... but how do we find the equivalent class in the second List to pass to the method below;

This is your actual problem; you must have at least one immutable property, a id or something like that, to identify corresponding objects in both lists. If you do not have such a property you, cannot solve the problem without errors. You can just try to guess corresponding objects by searching for minimal or logical changes.

If you have such an property, the solution becomes really simple.

Enumerable.Join(
   listA, listB,
   a => a.Id, b => b.Id,
   (a, b) => CompareTwoClass_ReturnDifferences(a, b))

thanks to you both danbruc and Noldorin for your feedback. both Lists will be the same length and in the same order. so the method above is close, but can you modify this method to pass the enum.Current to the method i posted above?

Now I am confused ... what is the problem with that? Why not just the following?

for (Int32 i = 0; i < Math.Min(listA.Count, listB.Count); i++)
{
    yield return CompareTwoClass_ReturnDifferences(listA[i], listB[i]);
}

The Math.Min() call may even be left out if equal length is guaranted.


Noldorin's implementation is of course smarter because of the delegate and the use of enumerators instead of using ICollection.

Preventing SQL injection in Node.js

Mysql-native has been outdated so it became MySQL2 that is a new module created with the help of the original MySQL module's team. This module has more features and I think it has what you want as it has prepared statements(by using.execute()) like in PHP for more security.

It's also very active(the last change was from 2-1 days) I didn't try it before but I think it's what you want and more.

Unable to Git-push master to Github - 'origin' does not appear to be a git repository / permission denied

I think that's another case of git error messages being misleading. Usually when I've seen that error it's due to ssh problems. Did you add your public ssh key to your github account?

Edit: Also, the xinet.d forum post is referring to running the git-daemon as a service so that people could pull from your system. It's not necessary to run git-daemon to push to github.

How to get current domain name in ASP.NET

Using Request.Url.Host is appropriate - it's how you retrieve the value of the HTTP Host: header, which specifies which hostname (domain name) the UA (browser) wants, as the Resource-path part of the HTTP request does not include the hostname.

Note that localhost:5858 is not a domain name, it is an endpoint specifier, also known as an "authority", which includes the hostname and TCP port number. This is retrieved by accessing Request.Uri.Authority.

Furthermore, it is not valid to get somedomain.com from www.somedomain.com because a webserver could be configured to serve a different site for www.somedomain.com compared to somedomain.com, however if you are sure this is valid in your case then you'll need to manually parse the hostname, though using String.Split('.') works in a pinch.

Note that webserver (IIS) configuration is distinct from ASP.NET's configuration, and that ASP.NET is actually completely ignorant of the HTTP binding configuration of the websites and web-applications that it runs under. The fact that both IIS and ASP.NET share the same configuration files (web.config) is a red-herring.

How to shut down the computer from C#

Different methods:

A. System.Diagnostics.Process.Start("Shutdown", "-s -t 10");

B. Windows Management Instrumentation (WMI)

C. System.Runtime.InteropServices Pinvoke

D. System Management

After I submit, I have seen so many others also have posted...

Python, add items from txt file into a list

names=[line.strip() for line in open('names.txt')]

How to programmatically determine the current checked out Git branch

If you are using gradle,

```

def gitHash = new ByteArrayOutputStream()    
project.exec {
                commandLine 'git', 'rev-parse', '--short', 'HEAD'
                standardOutput = gitHash
            }

def gitBranch = new ByteArrayOutputStream()   
project.exec {
                def gitCmd = "git symbolic-ref --short -q HEAD || git branch -rq --contains "+getGitHash()+" | sed -e '2,\$d'  -e 's/\\(.*\\)\\/\\(.*\\)\$/\\2/' || echo 'master'"
                commandLine "bash", "-c", "${gitCmd}"
                standardOutput = gitBranch
            }

```

Split varchar into separate columns in Oracle

Simple way is to convert into column

SELECT COLUMN_VALUE FROM TABLE (SPLIT ('19869,19572,19223,18898,10155,'))

CREATE TYPE split_tbl as TABLE OF VARCHAR2(32767);

CREATE OR REPLACE FUNCTION split (p_list VARCHAR2, p_del VARCHAR2 := ',')
   RETURN split_tbl
   PIPELINED IS
   l_idx PLS_INTEGER;
   l_list VARCHAR2 (32767) := p_list;
   l_value VARCHAR2 (32767);
BEGIN
   LOOP
      l_idx := INSTR (l_list, p_del);

      IF l_idx > 0 THEN
         PIPE ROW (SUBSTR (l_list, 1, l_idx - 1));
         l_list := SUBSTR (l_list, l_idx + LENGTH (p_del));
      ELSE
         PIPE ROW (l_list);
         EXIT;
      END IF;
   END LOOP;

   RETURN;
END split;

How to sum all the values in a dictionary?

phihag's answer (and similar ones) won't work in python3.

For python 3:

d = {'key1': 1,'key2': 14,'key3': 47}
sum(list(d.values()))

Update! There are complains that it doesn't work! I just attach a screenshot from my terminal. Could be some mismatch in versions etc.

enter image description here

How to fix Ora-01427 single-row subquery returns more than one row in select?

The only subquery appears to be this - try adding a ROWNUM limit to the where to be sure:

(SELECT C.I_WORKDATE
         FROM T_COMPENSATION C
         WHERE C.I_COMPENSATEDDATE = A.I_REQDATE AND ROWNUM <= 1
         AND C.I_EMPID = A.I_EMPID)

You do need to investigate why this isn't unique, however - e.g. the employee might have had more than one C.I_COMPENSATEDDATE on the matched date.

For performance reasons, you should also see if the lookup subquery can be rearranged into an inner / left join, i.e.

 SELECT 
    ...
    REPLACE(TO_CHAR(C.I_WORKDATE, 'DD-Mon-YYYY'),
            ' ',
            '') AS WORKDATE,
    ...
 INNER JOIN T_EMPLOYEE_MS E
    ...
     LEFT OUTER JOIN T_COMPENSATION C
          ON C.I_COMPENSATEDDATE = A.I_REQDATE
          AND C.I_EMPID = A.I_EMPID
    ...

How to use Bootstrap 4 in ASP.NET Core

As others already mentioned, the package manager Bower, that was usually used for dependencies like this in application that do not rely on heavy client-side scripting, is on the way out and actively recommending to move to other solutions:

..psst! While Bower is maintained, we recommend yarn and webpack for new front-end projects!

So although you can still use it right now, Bootstrap has also announced to drop support for it. As a result, the built-in ASP.NET Core templates are slowly being edited to move away from it too.

Unfortunately, there is no clear path forward. This is mostly due to the fact that web applications are continuously moving further into the client-side, requiring complex client-side build systems and many dependencies. So if you are building something like that, you might already know how to solve this then, and you can expand your existing build process to simply also include Bootstrap and jQuery there.

But there are still many web applications out there that are not that heavy on the client-side, where the application still runs mainly on the server and the server serves static views as a result. Bower previously filled this by making it easy to just publish client-side dependencies without that much of a process.

In the .NET world we also have NuGet and with previous ASP.NET versions, we could use NuGet as well to add dependencies to some client-side dependencies since NuGet would just place the content into our project correctly. Unfortunately, with the new .csproj format and the new NuGet, installed packages are located outside of our project, so we cannot simply reference those.

This leaves us with a few options how to add our dependencies:

One-time installation

This is what the ASP.NET Core templates, that are not single-page applications, are currently doing. When you use those to create a new application, the wwwroot folder simply contains a folder lib that contains the dependencies:

wwwroot folder contains lib folder with static dependencies

If you look closely at the files currently, you can see that they were originally placed there with Bower to create the template, but that is likely to change soon. The basic idea is that the files are copied once to the wwwroot folder so you can depend on them.

To do this, we can simply follow Bootstrap’s introduction and download the compiled files directly. As mentioned on the download site, this does not include jQuery, so we need to download that separately too; it does contain Popper.js though if we choose to use the bootstrap.bundle file later—which we will do. For jQuery, we can simply get a single “compressed, production” file from the download site (right-click the link and select "Save link as..." from the menu).

This leaves us with a few files which will simply extract and copy into the wwwroot folder. We can also make a lib folder to make it clearer that these are external dependencies:

wwwroot folder contains lib folder with our installed dependencies

That’s all we need, so now we just need to adjust our _Layout.cshtml file to include those dependencies. For that, we add the following block to the <head>:

<environment include="Development">
    <link rel="stylesheet" href="~/lib/css/bootstrap.css" />
</environment>
<environment exclude="Development">
    <link rel="stylesheet" href="~/lib/css/bootstrap.min.css" />
</environment>

And the following block at the very end of the <body>:

<environment include="Development">
    <script src="~/lib/js/jquery-3.3.1.js"></script>
    <script src="~/lib/js/bootstrap.bundle.js"></script>
</environment>
<environment exclude="Development">
    <script src="~/lib/js/jquery-3.3.1.min.js"></script>
    <script src="~/lib/js/bootstrap.bundle.min.js"></script>
</environment>

You can also just include the minified versions and skip the <environment> tag helpers here to make it a bit simpler. But that’s all you need to do to keep you starting.

Dependencies from NPM

The more modern way, also if you want to keep your dependencies updated, would be to get the dependencies from the NPM package repository. You can use either NPM or Yarn for this; in my example, I’ll use NPM.

To start off, we need to create a package.json file for our project, so we can specify our dependencies. To do this, we simply do that from the “Add New Item” dialog:

Add New Item: npm Configuration file

Once we have that, we need to edit it to include our dependencies. It should something look like this:

{
  "version": "1.0.0",
  "name": "asp.net",
  "private": true,
  "devDependencies": {
    "bootstrap": "4.0.0",
    "jquery": "3.3.1",
    "popper.js": "1.12.9"
  }
}

By saving, Visual Studio will already run NPM to install the dependencies for us. They will be installed into the node_modules folder. So what is left to do is to get the files from there into our wwwroot folder. There are a few options to do that:

bundleconfig.json for bundling and minification

We can use one of the various ways to consume a bundleconfig.json for bundling and minification, as explained in the documentation. A very easy way is to simply use the BuildBundlerMinifier NuGet package which automatically sets up a build task for this.

After installing that package, we need to create a bundleconfig.json at the root of the project with the following contents:

[
  {
    "outputFileName": "wwwroot/vendor.min.css",
    "inputFiles": [
      "node_modules/bootstrap/dist/css/bootstrap.min.css"
    ],
    "minify": { "enabled": false }
  },
  {
    "outputFileName": "wwwroot/vendor.min.js",
    "inputFiles": [
      "node_modules/jquery/dist/jquery.min.js",
      "node_modules/popper.js/dist/umd/popper.min.js",
      "node_modules/bootstrap/dist/js/bootstrap.min.js"
    ],
    "minify": { "enabled": false }
  }
]

This basically configures which files to combine into what. And when we build, we can see that the vendor.min.css and vendor.js.css are created correctly. So all we need to do is to adjust our _Layouts.html again to include those files:

<!-- inside <head> -->
<link rel="stylesheet" href="~/vendor.min.css" />

<!-- at the end of <body> -->
<script src="~/vendor.min.js"></script>

Using a task manager like Gulp

If we want to move a bit more into client-side development, we can also start to use tools that we would use there. For example Webpack which is a very commonly used build tool for really everything. But we can also start with a simpler task manager like Gulp and do the few necessary steps ourselves.

For that, we add a gulpfile.js into our project root, with the following contents:

const gulp = require('gulp');
const concat = require('gulp-concat');

const vendorStyles = [
    "node_modules/bootstrap/dist/css/bootstrap.min.css"
];
const vendorScripts = [
    "node_modules/jquery/dist/jquery.min.js",
    "node_modules/popper.js/dist/umd/popper.min.js",
    "node_modules/bootstrap/dist/js/bootstrap.min.js",
];

gulp.task('build-vendor-css', () => {
    return gulp.src(vendorStyles)
        .pipe(concat('vendor.min.css'))
        .pipe(gulp.dest('wwwroot'));
});

gulp.task('build-vendor-js', () => {
    return gulp.src(vendorScripts)
        .pipe(concat('vendor.min.js'))
        .pipe(gulp.dest('wwwroot'));
});

gulp.task('build-vendor', gulp.parallel('build-vendor-css', 'build-vendor-js'));

gulp.task('default', gulp.series('build-vendor'));

Now, we also need to adjust our package.json to have dependencies on gulp and gulp-concat:

{
  "version": "1.0.0",
  "name": "asp.net",
  "private": true,
  "devDependencies": {
    "bootstrap": "4.0.0",
    "gulp": "^4.0.2",
    "gulp-concat": "^2.6.1",
    "jquery": "3.3.1",
    "popper.js": "1.12.9"
  }
}

Finally, we edit our .csproj to add the following task which makes sure that our Gulp task runs when we build the project:

<Target Name="RunGulp" BeforeTargets="Build">
  <Exec Command="node_modules\.bin\gulp.cmd" />
</Target>

Now, when we build, the default Gulp task runs, which runs the build-vendor tasks, which then builds our vendor.min.css and vendor.min.js just like we did before. So after adjusting our _Layout.cshtml just like above, we can make use of jQuery and Bootstrap.

While the initial setup of Gulp is a bit more complicated than the bundleconfig.json one above, we have now have entered the Node-world and can start to make use of all the other cool tools there. So it might be worth to start with this.

Conclusion

While this suddenly got a lot more complicated than with just using Bower, we also do gain a lot of control with those new options. For example, we can now decide what files are actually included within the wwwroot folder and how those exactly look like. And we also can use this to make the first moves into the client-side development world with Node which at least should help a bit with the learning curve.

Facebook user url by id

The marked answer seems outdated and it won't work.

Facebook now only gives unique ID related to app which isn't equal to userId and profileUrl and username will come out to be empty.

Doing me?fields=id,name,links is also depreciated after Graph Version 2.4

The only option now is to request for user_links permission from your developer console.

enter image description here

and the pass it in scope when doing facebook login

scope: ['user_link'] }

or by doing an api call

Copying a local file from Windows to a remote server using scp

I see this post is very old, but in my search for an answer to this very question, I was unable to unearth a solution from the vast internet super highway. I, therefore, hope I can contribute and help someone as they too find themselves stumbling for an answer. This simple, natural question does not seem to be documented anywhere.

On Windows 10 Pro connecting to Windows 10 Pro, both running OpenSSH (Windows version 7.7p1, LibreSSL 2.6.5), I was able to find a solution by trial and error. Though surprisingly simple, it took a while. I found the required syntax to be

BY EXAMPLE INSTEAD OF MORE OBSCURE AND INCOMPLETE TEMPLATES:

Transferring securely from a remote system to your local system:

scp user@remotehost:\D\mySrcCode\ProjectFooBar\somefile.cpp C:\myRepo\ProjectFooBar

or going the other way around:

scp C:\myRepo\ProjectFooBar\somefile.cpp user@remotehost:\D\mySrcCode\ProjectFooBar

I also found that if spaces are in the path, the quotations should begin following the remote host name:

scp user@remotehost:"\D\My Long Folder Name\somefile.cpp" C:\myRepo\SimplerNamerBro

Also, for your particular case, I echo what Cornel says:

On Windows, use backslash, at least at conventional command console.

Kind Regards. RocketCityElectromagnetics

pass post data with window.location.href

it's as simple as this

$.post({url: "som_page.php", 
    data: { data1: value1, data2: value2 }
    ).done(function( data ) { 
        $( "body" ).html(data);
    });
});

I had to solve this to make a screen lock of my application where I had to pass sensitive data as user and the url where he was working. Then create a function that executes this code

Oracle date difference to get number of years

I had to implement a year diff function which works similarly to datediff. In that case the real year difference is counted, not the rounded day difference. So if there are two dates separated by one day, the year difference can be 1 (see select datediff(year, '20141231', '20150101')).

If the year diff has to be counted this way then use:

EXTRACT(YEAR FROM date_to) - EXTRACT(YEAR FROM date_from)

Just for the log the (almost) complete datediff function:

CREATE OR REPLACE FUNCTION datediff (datepart IN VARCHAR2, date_from IN DATE, date_to IN DATE)
RETURN NUMBER
AS
  diff NUMBER;
BEGIN
  diff :=  CASE datepart
    WHEN 'day'   THEN TRUNC(date_to,'DD') - TRUNC(date_from, 'DD')
    WHEN 'week'  THEN (TRUNC(date_to,'DAY') - TRUNC(date_from, 'DAY')) / 7
    WHEN 'month' THEN MONTHS_BETWEEN(TRUNC(date_to, 'MONTH'), TRUNC(date_from, 'MONTH'))
    WHEN 'year'  THEN EXTRACT(YEAR FROM date_to) - EXTRACT(YEAR FROM date_from)
  END;
  RETURN diff;
END;";

What parameters should I use in a Google Maps URL to go to a lat-lon?

If you need a name on your pin, you can also use:

http://maps.google.com/?q=MY%20LOCATION@lat,long

"405 method not allowed" in IIS7.5 for "PUT" method

I had this problem with WebDAV when hosting a MVC4 WebApi Project. I got around it by adding this line to the web.config:

<handlers>
  <remove name="WebDAV" />
  <add name="WebDAV" path="*" verb="*" modules="WebDAVModule"
      resourceType="Unspecified" requireAccess="None" />
</handlers>

As explained here: http://evolutionarydeveloper.blogspot.co.uk/2012/07/method-not-allowed-405-on-iis7-website.html

Get list of data-* attributes using javascript / jQuery

As mentioned above modern browsers have the The HTMLElement.dataset API.
That API gives you a DOMStringMap, and you can retrieve the list of data-* attributes simply doing:

var dataset = el.dataset; // as you asked in the question

you can also retrieve a array with the data- property's key names like

var data = Object.keys(el.dataset);

or map its values by

Object.keys(el.dataset).map(function(key){ return el.dataset[key];});
// or the ES6 way: Object.keys(el.dataset).map(key=>{ return el.dataset[key];});

and like this you can iterate those and use them without the need of filtering between all attributes of the element like we needed to do before.

How to configure log4j.properties for SpringJUnit4ClassRunner?

If you don't want to bother with a file, you can do something like this in your code:

static
{
    Logger rootLogger = Logger.getRootLogger();
    rootLogger.setLevel(Level.INFO);
    rootLogger.addAppender(new ConsoleAppender(
               new PatternLayout("%-6r [%p] %c - %m%n")));
}

Angular JS: What is the need of the directive’s link function when we already had directive’s controller with scope?

Why controllers are needed

The difference between link and controller comes into play when you want to nest directives in your DOM and expose API functions from the parent directive to the nested ones.

From the docs:

Best Practice: use controller when you want to expose an API to other directives. Otherwise use link.

Say you want to have two directives my-form and my-text-input and you want my-text-input directive to appear only inside my-form and nowhere else.

In that case, you will say while defining the directive my-text-input that it requires a controller from the parent DOM element using the require argument, like this: require: '^myForm'. Now the controller from the parent element will be injected into the link function as the fourth argument, following $scope, element, attributes. You can call functions on that controller and communicate with the parent directive.

Moreover, if such a controller is not found, an error will be raised.

Why use link at all

There is no real need to use the link function if one is defining the controller since the $scope is available on the controller. Moreover, while defining both link and controller, one does need to be careful about the order of invocation of the two (controller is executed before).

However, in keeping with the Angular way, most DOM manipulation and 2-way binding using $watchers is usually done in the link function while the API for children and $scope manipulation is done in the controller. This is not a hard and fast rule, but doing so will make the code more modular and help in separation of concerns (controller will maintain the directive state and link function will maintain the DOM + outside bindings).

MySQL "NOT IN" query

Be carefull NOT IN is not an alias for <> ANY, but for <> ALL!

http://dev.mysql.com/doc/refman/5.0/en/any-in-some-subqueries.html

SELECT c FROM t1 LEFT JOIN t2 USING (c) WHERE t2.c IS NULL

cant' be replaced by

SELECT c FROM t1 WHERE c NOT IN (SELECT c FROM t2)

You must use

SELECT c FROM t1 WHERE c <> ANY (SELECT c FROM t2)

CSS Change List Item Background Color with Class

The ul.nav li is more restrictive and so takes precedence, try this:

ul.nav li.selected {  
  background-color:red; 
}

Storing C++ template function definitions in a .CPP file

This code is well-formed. You only have to pay attention that the definition of the template is visible at the point of instantiation. To quote the standard, § 14.7.2.4:

The definition of a non-exported function template, a non-exported member function template, or a non-exported member function or static data member of a class template shall be present in every translation unit in which it is explicitly instantiated.

Passing on command line arguments to runnable JAR

You can pass program arguments on the command line and get them in your Java app like this:

public static void main(String[] args) {
  String pathToXml = args[0];
....
}

Alternatively you pass a system property by changing the command line to:

java -Dpath-to-xml=enwiki-20111007-pages-articles.xml -jar wiki2txt

and your main class to:

public static void main(String[] args) {
  String pathToXml = System.getProperty("path-to-xml");
....
}

Tkinter: How to use threads to preventing main event loop from "freezing"

I will submit the basis for an alternate solution. It is not specific to a Tk progress bar per se, but it can certainly be implemented very easily for that.

Here are some classes that allow you to run other tasks in the background of Tk, update the Tk controls when desired, and not lock up the gui!

Here's class TkRepeatingTask and BackgroundTask:

import threading

class TkRepeatingTask():

    def __init__( self, tkRoot, taskFuncPointer, freqencyMillis ):
        self.__tk_   = tkRoot
        self.__func_ = taskFuncPointer        
        self.__freq_ = freqencyMillis
        self.__isRunning_ = False

    def isRunning( self ) : return self.__isRunning_ 

    def start( self ) : 
        self.__isRunning_ = True
        self.__onTimer()

    def stop( self ) : self.__isRunning_ = False

    def __onTimer( self ): 
        if self.__isRunning_ :
            self.__func_() 
            self.__tk_.after( self.__freq_, self.__onTimer )

class BackgroundTask():

    def __init__( self, taskFuncPointer ):
        self.__taskFuncPointer_ = taskFuncPointer
        self.__workerThread_ = None
        self.__isRunning_ = False

    def taskFuncPointer( self ) : return self.__taskFuncPointer_

    def isRunning( self ) : 
        return self.__isRunning_ and self.__workerThread_.isAlive()

    def start( self ): 
        if not self.__isRunning_ :
            self.__isRunning_ = True
            self.__workerThread_ = self.WorkerThread( self )
            self.__workerThread_.start()

    def stop( self ) : self.__isRunning_ = False

    class WorkerThread( threading.Thread ):
        def __init__( self, bgTask ):      
            threading.Thread.__init__( self )
            self.__bgTask_ = bgTask

        def run( self ):
            try :
                self.__bgTask_.taskFuncPointer()( self.__bgTask_.isRunning )
            except Exception as e: print repr(e)
            self.__bgTask_.stop()

Here's a Tk test which demos the use of these. Just append this to the bottom of the module with those classes in it if you want to see the demo in action:

def tkThreadingTest():

    from tkinter import Tk, Label, Button, StringVar
    from time import sleep

    class UnitTestGUI:

        def __init__( self, master ):
            self.master = master
            master.title( "Threading Test" )

            self.testButton = Button( 
                self.master, text="Blocking", command=self.myLongProcess )
            self.testButton.pack()

            self.threadedButton = Button( 
                self.master, text="Threaded", command=self.onThreadedClicked )
            self.threadedButton.pack()

            self.cancelButton = Button( 
                self.master, text="Stop", command=self.onStopClicked )
            self.cancelButton.pack()

            self.statusLabelVar = StringVar()
            self.statusLabel = Label( master, textvariable=self.statusLabelVar )
            self.statusLabel.pack()

            self.clickMeButton = Button( 
                self.master, text="Click Me", command=self.onClickMeClicked )
            self.clickMeButton.pack()

            self.clickCountLabelVar = StringVar()            
            self.clickCountLabel = Label( master,  textvariable=self.clickCountLabelVar )
            self.clickCountLabel.pack()

            self.threadedButton = Button( 
                self.master, text="Timer", command=self.onTimerClicked )
            self.threadedButton.pack()

            self.timerCountLabelVar = StringVar()            
            self.timerCountLabel = Label( master,  textvariable=self.timerCountLabelVar )
            self.timerCountLabel.pack()

            self.timerCounter_=0

            self.clickCounter_=0

            self.bgTask = BackgroundTask( self.myLongProcess )

            self.timer = TkRepeatingTask( self.master, self.onTimer, 1 )

        def close( self ) :
            print "close"
            try: self.bgTask.stop()
            except: pass
            try: self.timer.stop()
            except: pass            
            self.master.quit()

        def onThreadedClicked( self ):
            print "onThreadedClicked"
            try: self.bgTask.start()
            except: pass

        def onTimerClicked( self ) :
            print "onTimerClicked"
            self.timer.start()

        def onStopClicked( self ) :
            print "onStopClicked"
            try: self.bgTask.stop()
            except: pass
            try: self.timer.stop()
            except: pass                        

        def onClickMeClicked( self ):
            print "onClickMeClicked"
            self.clickCounter_+=1
            self.clickCountLabelVar.set( str(self.clickCounter_) )

        def onTimer( self ) :
            print "onTimer"
            self.timerCounter_+=1
            self.timerCountLabelVar.set( str(self.timerCounter_) )

        def myLongProcess( self, isRunningFunc=None ) :
            print "starting myLongProcess"
            for i in range( 1, 10 ):
                try:
                    if not isRunningFunc() :
                        self.onMyLongProcessUpdate( "Stopped!" )
                        return
                except : pass   
                self.onMyLongProcessUpdate( i )
                sleep( 1.5 ) # simulate doing work
            self.onMyLongProcessUpdate( "Done!" )                

        def onMyLongProcessUpdate( self, status ) :
            print "Process Update: %s" % (status,)
            self.statusLabelVar.set( str(status) )

    root = Tk()    
    gui = UnitTestGUI( root )
    root.protocol( "WM_DELETE_WINDOW", gui.close )
    root.mainloop()

if __name__ == "__main__": 
    tkThreadingTest()

Two import points I'll stress about BackgroundTask:

1) The function you run in the background task needs to take a function pointer it will both invoke and respect, which allows the task to be cancelled mid way through - if possible.

2) You need to make sure the background task is stopped when you exit your application. That thread will still run even if your gui is closed if you don't address that!

insert/delete/update trigger in SQL server

Not possible, per MSDN:

You can have the same code execute for multiple trigger types, but the syntax does not allow for multiple code blocks in one trigger:

Trigger on an INSERT, UPDATE, or DELETE statement to a table or view (DML Trigger)

CREATE TRIGGER [ schema_name . ]trigger_name 
ON { table | view } 
[ WITH <dml_trigger_option> [ ,...n ] ]
{ FOR | AFTER | INSTEAD OF } 
{ [ INSERT ] [ , ] [ UPDATE ] [ , ] [ DELETE ] } 
[ NOT FOR REPLICATION ] 
AS { sql_statement  [ ; ] [ ,...n ] | EXTERNAL NAME <method specifier [ ; ] > }

how to transfer a file through SFTP in java?

Try this code.

public void send (String fileName) {
    String SFTPHOST = "host:IP";
    int SFTPPORT = 22;
    String SFTPUSER = "username";
    String SFTPPASS = "password";
    String SFTPWORKINGDIR = "file/to/transfer";

    Session session = null;
    Channel channel = null;
    ChannelSftp channelSftp = null;
    System.out.println("preparing the host information for sftp.");

    try {
        JSch jsch = new JSch();
        session = jsch.getSession(SFTPUSER, SFTPHOST, SFTPPORT);
        session.setPassword(SFTPPASS);
        java.util.Properties config = new java.util.Properties();
        config.put("StrictHostKeyChecking", "no");
        session.setConfig(config);
        session.connect();
        System.out.println("Host connected.");
        channel = session.openChannel("sftp");
        channel.connect();
        System.out.println("sftp channel opened and connected.");
        channelSftp = (ChannelSftp) channel;
        channelSftp.cd(SFTPWORKINGDIR);
        File f = new File(fileName);
        channelSftp.put(new FileInputStream(f), f.getName());
        log.info("File transfered successfully to host.");
    } catch (Exception ex) {
        System.out.println("Exception found while tranfer the response.");
    } finally {
        channelSftp.exit();
        System.out.println("sftp Channel exited.");
        channel.disconnect();
        System.out.println("Channel disconnected.");
        session.disconnect();
        System.out.println("Host Session disconnected.");
    }
}   

Is it possible for UIStackView to scroll?

I was looking to do the same thing and stumbled upon this excellent post. If you want to do this programmatically using the anchor API, this is the way to go.

To summarize, embed your UIStackView in your UIScrollView, and set the anchor constraints of the UIStackView to match those of the UIScrollView:

stackView.leadingAnchor.constraintEqualToAnchor(scrollView.leadingAnchor).active = true
stackView.trailingAnchor.constraintEqualToAnchor(scrollView.trailingAnchor).active = true
stackView.bottomAnchor.constraintEqualToAnchor(scrollView.bottomAnchor).active = true
stackView.topAnchor.constraintEqualToAnchor(scrollView.topAnchor).active = true
stackView.widthAnchor.constraintEqualToAnchor(scrollView.widthAnchor).active = true

How can I take an UIImage and give it a black border?

You could manipulate the image itself, but a much better way is to simply add a UIView that contains the UIImageView, and change the background to black. Then set the size of that container view to a little bit larger than the UIImageView.

Export database schema into SQL file

You can generate scripts to a file via SQL Server Management Studio, here are the steps:

  1. Right click the database you want to generate scripts for (not the table) and select tasks - generate scripts
  2. Next, select the requested table/tables, views, stored procedures, etc (from select specific database objects)
  3. Click advanced - select the types of data to script
  4. Click Next and finish

MSDN Generate Scripts

When generating the scripts, there is an area that will allow you to script, constraints, keys, etc. From SQL Server 2008 R2 there is an Advanced Option under scripting:

enter image description here

How to pull remote branch from somebody else's repo

The following is a nice expedient solution that works with GitHub for checking out the PR branch from another user's fork. You need to know the pull request ID (which GitHub displays along with the PR title).

Example:

Fixing your insecure code #8
alice wants to merge 1 commit into your_repo:master from her_repo:branch

git checkout -b <branch>
git pull origin pull/8/head

Substitute your remote if different from origin.
Substitute 8 with the correct pull request ID.

how do I get eclipse to use a different compiler version for Java?

First off, are you setting your desired JRE or your desired JDK?

Even if your Eclipse is set up properly, there might be a wacky project-specific setting somewhere. You can open up a context menu on a given Java project in the Project Explorer and select Properties > Java Compiler to check on that.

If none of that helps, leave a comment and I'll take another look.

How to set Angular 4 background image?

this one is working for me also for internet explorer:

<div class="col imagebox" [ngStyle]="bkUrl"></div>

...

@Input() background = '571x450img';  
bkUrl = {};   
ngOnInit() {
    this.bkUrl = this.getBkUrl();
  }
getBkUrl() {
    const styles = {
      'background-image': 'url(src/assets/images/' + this.background + '.jpg)'
    };
    console.log(styles);
    return styles;
  }

Why is this program erroneously rejected by three C++ compilers?

You forgot the pre-processor. Try this:

pngtopnm helloworld.png | ocrad | g++ -x 'c++' -

Method List in Visual Studio Code

There's no such feature today, the CTRL+SHIFT+O == CTRL+P @ doesn't work for all languages.

As a last resort you can use the search panel - although it is not so fast an easy to use as you'd like - you can enter this regex in the search panel to find all functions:

function\s([_A-Za-z0-9]+)\s*\(

Initialize array of strings

This example program illustrates initialization of an array of C strings.

#include <stdio.h>

const char * array[] = {
    "First entry",
    "Second entry",
    "Third entry",
};

#define n_array (sizeof (array) / sizeof (const char *))

int main ()
{
    int i;

    for (i = 0; i < n_array; i++) {
        printf ("%d: %s\n", i, array[i]);
    }
    return 0;
}

It prints out the following:

0: First entry
1: Second entry
2: Third entry

Convert Mat to Array/Vector in OpenCV

You can use iterators:

Mat matrix = ...;

std::vector<float> vec(matrix.begin<float>(), matrix.end<float>());

Passing parameters to a Bash function

Another way to pass named parameters to Bash... is passing by reference. This is supported as of Bash 4.0

#!/bin/bash
function myBackupFunction(){ # directory options destination filename
local directory="$1" options="$2" destination="$3" filename="$4";
  echo "tar cz ${!options} ${!directory} | ssh root@backupserver \"cat > /mnt/${!destination}/${!filename}.tgz\"";
}

declare -A backup=([directory]=".." [options]="..." [destination]="backups" [filename]="backup" );

myBackupFunction backup[directory] backup[options] backup[destination] backup[filename];

An alternative syntax for Bash 4.3 is using a nameref.

Although the nameref is a lot more convenient in that it seamlessly dereferences, some older supported distros still ship an older version, so I won't recommend it quite yet.

How to set MimeBodyPart ContentType to "text/html"?

Don't know why (the method is not documented), but by looking at the source code, this line should do it :

mime_body_part.setHeader("Content-Type", "text/html");

Convert double to BigDecimal and set BigDecimal Precision

In Java 9 the following is deprecated:

BigDecimal.valueOf(d).setScale(2, BigDecimal.ROUND_HALF_UP);

instead use:

BigDecimal.valueOf(d).setScale(2, RoundingMode.HALF_UP);

Example:

    double d = 47.48111;

    System.out.println(BigDecimal.valueOf(d)); //Prints: 47.48111

    BigDecimal bigDecimal = BigDecimal.valueOf(d).setScale(2, RoundingMode.HALF_UP);
    System.out.println(bigDecimal); //Prints: 47.48

Refresh a page using JavaScript or HTML

window.location.reload()

should work however there are many different options like:

window.location.href=window.location.href

Getting an error "fopen': This function or variable may be unsafe." when compling

This is a warning for usual. You can either disable it by

#pragma warning(disable:4996)

or simply use fopen_s like Microsoft has intended.

But be sure to use the pragma before other headers.

Map.Entry: How to use it?

Hash-Map stores the (key,value) pair as the Map.Entry Type.As you know that Hash-Map uses Linked Hash-Map(In case Collision occurs). Therefore each Node in the Bucket of Hash-Map is of Type Map.Entry. So whenever you iterate through the Hash-Map you will get Nodes of Type Map.Entry.

Now in your example when you are iterating through the Hash-Map, you will get Map.Entry Type(Which is Interface), To get the Key and Value from this Map.Entry Node Object, interface provided methods like getValue(), getKey() etc. So as per the code, In your Object you are adding all operators JButtons viz (+,-,/,*,=).

How to maintain a Unique List in Java?

You may want to use one of the implementing class of java.util.Set<E> Interface e.g. java.util.HashSet<String> collection class.

A collection that contains no duplicate elements. More formally, sets contain no pair of elements e1 and e2 such that e1.equals(e2), and at most one null element. As implied by its name, this interface models the mathematical set abstraction.

percentage of two int?

Well to make the decimal into a percent you can do this,

float percentage = (correct * 100.0f) / questionNum;

Disable form auto submit on button click

Buttons like <button>Click to do something</button> are submit buttons.

Set type="button" to change that. type="submit" is the default (as specified by the HTML recommendation).

label or @html.Label ASP.net MVC 4

When it comes to labels, I would say it's up to you what you prefer. Some examples when it can be useful with HTML helper tags are, for instance

  • When dealing with hyperlinks, since the HTML helper simplifies routing
  • When you bind to your model, using @Html.LabelFor, @Html.TextBoxFor, etc
  • When you use the @Html.EditorFor, as you can assign specific behavior och looks in a editor view

SQLite: How do I save the result of a query as a CSV file?

From here and d5e5's comment:

You'll have to switch the output to csv-mode and switch to file output.

sqlite> .mode csv
sqlite> .output test.csv
sqlite> select * from tbl1;
sqlite> .output stdout

How to deal with missing src/test/java source folder in Android/Maven project?

We can add java folder from

  1. Build Path -> Source.
  2. click on Add Folder.
  3. Select main as the container.
  4. click on Create Folder.
  5. Enter Folder name as java.
  6. Click on Finish

It works fine.

Add Favicon to Website

  1. This is not done in PHP. It's part of the <head> tags in a HTML page.
  2. That icon is called a favicon. According to Wikipedia:

    A favicon (short for favorites icon), also known as a shortcut icon, website icon, URL icon, or bookmark icon is a 16×16 or 32×32 pixel square icon associated with a particular website or webpage.

  3. Adding it is easy. Just add an .ico image file that is either 16x16 pixels or 32x32 pixels. Then, in the web pages, add <link rel="shortcut icon" href="favicon.ico" type="image/x-icon"> to the <head> element.
  4. You can easily generate favicons here.

Converting NSData to NSString in Objective c

-[NSString initWithData:encoding] will return nil if the specified encoding doesn't match the data's encoding.

Make sure your data is encoded in UTF-8 (or change NSUTF8StringEncoding to whatever encoding that's appropriate for the data).

How do I clone a github project to run locally?

I use @Thiho answer but i get this error:

'git' is not recognized as an internal or external command

For solving that i use this steps:

I add the following paths to PATH:

  • C:\Program Files\Git\bin\

  • C:\Program Files\Git\cmd\

In windows 7:

  1. Right-click "Computer" on the Desktop or Start Menu.
  2. Select "Properties".
  3. On the very far left, click the "Advanced system settings" link.
  4. Click the "Environment Variables" button at the bottom.
  5. Double-click the "Path" entry under "System variables".
  6. At the end of "Variable value", insert a ; if there is not already one, and then C:\Program Files\Git\bin\;C:\Program Files\Git\cmd. Do not put a space between ; and the entry.

Finally close and re-open your console.

extract month from date in python

Alternate solution

Create a column that will store the month:

data['month'] = data['date'].dt.month

Create a column that will store the year:

data['year'] = data['date'].dt.year

Replace all elements of Python NumPy Array that are greater than some value

I think you can achieve this the quickest by using the where function:

For example looking for items greater than 0.2 in a numpy array and replacing those with 0:

import numpy as np

nums = np.random.rand(4,3)

print np.where(nums > 0.2, 0, nums)

Timing a command's execution in PowerShell

Just a word on drawing (incorrect) conclusions from any of the performance measurement commands referred to in the answers. There are a number of pitfalls that should taken in consideration aside from looking to the bare invocation time of a (custom) function or command.

Sjoemelsoftware

'Sjoemelsoftware' voted Dutch word of the year 2015
Sjoemelen means cheating, and the word sjoemelsoftware came into being due to the Volkswagen emissions scandal. The official definition is "software used to influence test results".

Personally, I think that "Sjoemelsoftware" is not always deliberately created to cheat test results but might originate from accommodating practical situation that are similar to test cases as shown below.

As an example, using the listed performance measurement commands, Language Integrated Query (LINQ)(1), is often qualified as the fasted way to get something done and it often is, but certainly not always! Anybody who measures a speed increase of a factor 40 or more in comparison with native PowerShell commands, is probably incorrectly measuring or drawing an incorrect conclusion.

The point is that some .Net classes (like LINQ) using a lazy evaluation (also referred to as deferred execution(2)). Meaning that when assign an expression to a variable, it almost immediately appears to be done but in fact it didn't process anything yet!

Let presume that you dot-source your . .\Dosomething.ps1 command which has either a PowerShell or a more sophisticated Linq expression (for the ease of explanation, I have directly embedded the expressions directly into the Measure-Command):

$Data = @(1..100000).ForEach{[PSCustomObject]@{Index=$_;Property=(Get-Random)}}

(Measure-Command {
    $PowerShell = $Data.Where{$_.Index -eq 12345}
}).totalmilliseconds
864.5237

(Measure-Command {
    $Linq = [Linq.Enumerable]::Where($Data, [Func[object,bool]] { param($Item); Return $Item.Index -eq 12345})
}).totalmilliseconds
24.5949

The result appears obvious, the later Linq command is a about 40 times faster than the first PowerShell command. Unfortunately, it is not that simple...

Let's display the results:

PS C:\> $PowerShell

Index  Property
-----  --------
12345 104123841

PS C:\> $Linq

Index  Property
-----  --------
12345 104123841

As expected, the results are the same but if you have paid close attention, you will have noticed that it took a lot longer to display the $Linq results then the $PowerShell results.
Let's specifically measure that by just retrieving a property of the resulted object:

PS C:\> (Measure-Command {$PowerShell.Property}).totalmilliseconds
14.8798
PS C:\> (Measure-Command {$Linq.Property}).totalmilliseconds
1360.9435

It took about a factor 90 longer to retrieve a property of the $Linq object then the $PowerShell object and that was just a single object!

Also notice an other pitfall that if you do it again, certain steps might appear a lot faster then before, this is because some of the expressions have been cached.

Bottom line, if you want to compare the performance between two functions, you will need to implement them in your used case, start with a fresh PowerShell session and base your conclusion on the actual performance of the complete solution.

(1) For more background and examples on PowerShell and LINQ, I recommend tihis site: High Performance PowerShell with LINQ
(2) I think there is a minor difference between the two concepts as with lazy evaluation the result is calculated when needed as apposed to deferred execution were the result is calculated when the system is idle

Find JavaScript function definition in Chrome

in Chrome console:

debug(MyFunction)
MyFunction()

PHP error: Notice: Undefined index:

How I can get rid of it so it doesnt display it?

People here are trying to tell you that it's unprofessional (and it is), but in your case you should simply add following to the start of your application:

 error_reporting(E_ERROR|E_WARNING);

This will disable E_NOTICE reporting. E_NOTICES are not errors, but notices, as the name says. You'd better check this stuff out and proof that undefined variables don't lead to errors. But the common case is that they are just informal, and perfectly normal for handling form input with PHP.

Also, next time Google the error message first.

Modifying local variable from inside lambda

Yes, you can modify local variables from inside lambdas (in the way shown by the other answers), but you should not do it. Lambdas have been made for functional style of programming and this means: No side effects. What you want to do is considered bad style. It is also dangerous in case of parallel streams.

You should either find a solution without side effects or use a traditional for loop.

Bootstrap 3 offset on right not left

I'm using the following simple custom CSS I wrote to achieve this.

.col-xs-offset-right-12 {
  margin-right: 100%;
}
.col-xs-offset-right-11 {
  margin-right: 91.66666667%;
}
.col-xs-offset-right-10 {
  margin-right: 83.33333333%;
}
.col-xs-offset-right-9 {
  margin-right: 75%;
}
.col-xs-offset-right-8 {
  margin-right: 66.66666667%;
}
.col-xs-offset-right-7 {
  margin-right: 58.33333333%;
}
.col-xs-offset-right-6 {
  margin-right: 50%;
}
.col-xs-offset-right-5 {
  margin-right: 41.66666667%;
}
.col-xs-offset-right-4 {
  margin-right: 33.33333333%;
}
.col-xs-offset-right-3 {
  margin-right: 25%;
}
.col-xs-offset-right-2 {
  margin-right: 16.66666667%;
}
.col-xs-offset-right-1 {
  margin-right: 8.33333333%;
}
.col-xs-offset-right-0 {
  margin-right: 0;
}
@media (min-width: 768px) {
  .col-sm-offset-right-12 {
    margin-right: 100%;
  }
  .col-sm-offset-right-11 {
    margin-right: 91.66666667%;
  }
  .col-sm-offset-right-10 {
    margin-right: 83.33333333%;
  }
  .col-sm-offset-right-9 {
    margin-right: 75%;
  }
  .col-sm-offset-right-8 {
    margin-right: 66.66666667%;
  }
  .col-sm-offset-right-7 {
    margin-right: 58.33333333%;
  }
  .col-sm-offset-right-6 {
    margin-right: 50%;
  }
  .col-sm-offset-right-5 {
    margin-right: 41.66666667%;
  }
  .col-sm-offset-right-4 {
    margin-right: 33.33333333%;
  }
  .col-sm-offset-right-3 {
    margin-right: 25%;
  }
  .col-sm-offset-right-2 {
    margin-right: 16.66666667%;
  }
  .col-sm-offset-right-1 {
    margin-right: 8.33333333%;
  }
  .col-sm-offset-right-0 {
    margin-right: 0;
  }
}
@media (min-width: 992px) {
  .col-md-offset-right-12 {
    margin-right: 100%;
  }
  .col-md-offset-right-11 {
    margin-right: 91.66666667%;
  }
  .col-md-offset-right-10 {
    margin-right: 83.33333333%;
  }
  .col-md-offset-right-9 {
    margin-right: 75%;
  }
  .col-md-offset-right-8 {
    margin-right: 66.66666667%;
  }
  .col-md-offset-right-7 {
    margin-right: 58.33333333%;
  }
  .col-md-offset-right-6 {
    margin-right: 50%;
  }
  .col-md-offset-right-5 {
    margin-right: 41.66666667%;
  }
  .col-md-offset-right-4 {
    margin-right: 33.33333333%;
  }
  .col-md-offset-right-3 {
    margin-right: 25%;
  }
  .col-md-offset-right-2 {
    margin-right: 16.66666667%;
  }
  .col-md-offset-right-1 {
    margin-right: 8.33333333%;
  }
  .col-md-offset-right-0 {
    margin-right: 0;
  }
}
@media (min-width: 1200px) {
  .col-lg-offset-right-12 {
    margin-right: 100%;
  }
  .col-lg-offset-right-11 {
    margin-right: 91.66666667%;
  }
  .col-lg-offset-right-10 {
    margin-right: 83.33333333%;
  }
  .col-lg-offset-right-9 {
    margin-right: 75%;
  }
  .col-lg-offset-right-8 {
    margin-right: 66.66666667%;
  }
  .col-lg-offset-right-7 {
    margin-right: 58.33333333%;
  }
  .col-lg-offset-right-6 {
    margin-right: 50%;
  }
  .col-lg-offset-right-5 {
    margin-right: 41.66666667%;
  }
  .col-lg-offset-right-4 {
    margin-right: 33.33333333%;
  }
  .col-lg-offset-right-3 {
    margin-right: 25%;
  }
  .col-lg-offset-right-2 {
    margin-right: 16.66666667%;
  }
  .col-lg-offset-right-1 {
    margin-right: 8.33333333%;
  }
  .col-lg-offset-right-0 {
    margin-right: 0;
  }
}

How to install Openpyxl with pip

(optional) Install git for windows (https://git-scm.com/) to get git bash. Git bash is much more similar to Linux terminal than Windows cmd.

Install Anaconda 3

https://www.anaconda.com/download/

It should set itself into Windows PATH. Restart your PC. Then pip should work in your cmd

Then in cmd (or git bash), run command

pip install openpyxl

Can I access variables from another file?

You can export the variable from first file using export.

//first.js
const colorCode = {
    black: "#000",
    white: "#fff"
};
export { colorCode };

Then, import the variable in second file using import.

//second.js
import { colorCode } from './first.js'

export - MDN

What's with the dollar sign ($"string")

It's the new feature in C# 6 called Interpolated Strings.

The easiest way to understand it is: an interpolated string expression creates a string by replacing the contained expressions with the ToString representations of the expressions' results.

For more details about this, please take a look at MSDN.

Now, think a little bit more about it. Why this feature is great?

For example, you have class Point:

public class Point
{
    public int X { get; set; }

    public int Y { get; set; }
}

Create 2 instances:

var p1 = new Point { X = 5, Y = 10 };
var p2 = new Point { X = 7, Y = 3 };

Now, you want to output it to the screen. The 2 ways that you usually use:

Console.WriteLine("The area of interest is bounded by (" + p1.X + "," + p1.Y + ") and (" + p2.X + "," + p2.Y + ")");

As you can see, concatenating string like this makes the code hard to read and error-prone. You may use string.Format() to make it nicer:

Console.WriteLine(string.Format("The area of interest is bounded by({0},{1}) and ({2},{3})", p1.X, p1.Y, p2.X, p2.Y));

This creates a new problem:

  1. You have to maintain the number of arguments and index yourself. If the number of arguments and index are not the same, it will generate a runtime error.

For those reasons, we should use new feature:

Console.WriteLine($"The area of interest is bounded by ({p1.X},{p1.Y}) and ({p2.X},{p2.Y})");

The compiler now maintains the placeholders for you so you don’t have to worry about indexing the right argument because you simply place it right there in the string.

For the full post, please read this blog.

What are the safe characters for making URLs?

Between 3-50 characters. Can contain lowercase letters, numbers and special characters - dot(.), dash(-), underscore(_) and at the rate(@).

How to replace captured groups only?

A simplier option is to just capture the digits and replace them.

_x000D_
_x000D_
const name = 'preceding_text_0_following_text';_x000D_
const matcher = /(\d+)/;_x000D_
_x000D_
// Replace with whatever you would like_x000D_
const newName = name.replace(matcher, 'NEW_STUFF');_x000D_
console.log("Full replace", newName);_x000D_
_x000D_
// Perform work on the match and replace using a function_x000D_
// In this case increment it using an arrow function_x000D_
const incrementedName = name.replace(matcher, (match) => ++match);_x000D_
console.log("Increment", incrementedName);
_x000D_
_x000D_
_x000D_

Resources

Setting the JVM via the command line on Windows

If you have 2 installations of the JVM. Place the version upfront. Linux : export PATH=/usr/lib/jvm/java-8-oracle/bin:$PATH

This eliminates the ambiguity.

Split a String into an array in Swift?

I was looking for loosy split, such as PHP's explode where empty sequences are included in resulting array, this worked for me:

"First ".split(separator: " ", maxSplits: 1, omittingEmptySubsequences: false)

Output:

["First", ""]

Hibernate: flush() and commit()

session.flush() is synchronise method means to insert data in to database sequentially.if we use this method data will not store in database but it will store in cache,if any exception will rise in middle we can handle it. But commit() it will store data in database,if we are storing more amount of data then ,there may be chance to get out Of Memory Exception,As like in JDBC program in Save point topic

When should I use semicolons in SQL Server?

Personal opinion: Use them only where they are required. (See TheTXI's answer above for the required list.)

Since the compiler doesn't require them, you can put them all over, but why? The compiler won't tell you where you forgot one, so you'll end up with inconsistent use.

[This opinion is specific to SQL Server. Other databases may have more-stringent requirements. If you're writing SQL to run on multiple databases, your requirements may vary.]

tpdi stated above, "in a script, as you're sending more than one statement, you need it." That's actually not correct. You don't need them.

PRINT 'Semicolons are optional'
PRINT 'Semicolons are optional'
PRINT 'Semicolons are optional';
PRINT 'Semicolons are optional';

Output:

Semicolons are optional
Semicolons are optional
Semicolons are optional
Semicolons are optional

Converting Select results into Insert script - SQL Server

I think its also possible with adhoc queries you can export result to excel file and then import that file into your datatable object or use it as it is and then import the excel file into the second database have a look at this link this can help u alot.

http://vscontrols.blogspot.com/2010/09/import-and-export-excel-to-sql-server.html

What is the default value for enum variable?

You can use this snippet :-D

using System;
using System.Reflection;

public static class EnumUtils
{
    public static T GetDefaultValue<T>()
        where T : struct, Enum
    {
        return (T)GetDefaultValue(typeof(T));
    }

    public static object GetDefaultValue(Type enumType)
    {
        var attribute = enumType.GetCustomAttribute<DefaultValueAttribute>(inherit: false);
        if (attribute != null)
            return attribute.Value;

        var innerType = enumType.GetEnumUnderlyingType();
        var zero = Activator.CreateInstance(innerType);
        if (enumType.IsEnumDefined(zero))
            return zero;

        var values = enumType.GetEnumValues();
        return values.GetValue(0);
    }
}

Example:

using System;

public enum Enum1
{
    Foo,
    Bar,
    Baz,
    Quux
}
public enum Enum2
{
    Foo  = 1,
    Bar  = 2,
    Baz  = 3,
    Quux = 0
}
public enum Enum3
{
    Foo  = 1,
    Bar  = 2,
    Baz  = 3,
    Quux = 4
}
[DefaultValue(Enum4.Bar)]
public enum Enum4
{
    Foo  = 1,
    Bar  = 2,
    Baz  = 3,
    Quux = 4
}

public static class Program 
{
    public static void Main() 
    {
        var defaultValue1 = EnumUtils.GetDefaultValue<Enum1>();
        Console.WriteLine(defaultValue1); // Foo

        var defaultValue2 = EnumUtils.GetDefaultValue<Enum2>();
        Console.WriteLine(defaultValue2); // Quux

        var defaultValue3 = EnumUtils.GetDefaultValue<Enum3>();
        Console.WriteLine(defaultValue3); // Foo

        var defaultValue4 = EnumUtils.GetDefaultValue<Enum4>();
        Console.WriteLine(defaultValue4); // Bar
    }
}

selecting from multi-index pandas

Understanding how to access multi-indexed pandas DataFrame can help you with all kinds of task like that.

Copy paste this in your code to generate example:

# hierarchical indices and columns
index = pd.MultiIndex.from_product([[2013, 2014], [1, 2]],
                                   names=['year', 'visit'])
columns = pd.MultiIndex.from_product([['Bob', 'Guido', 'Sue'], ['HR', 'Temp']],
                                     names=['subject', 'type'])

# mock some data
data = np.round(np.random.randn(4, 6), 1)
data[:, ::2] *= 10
data += 37

# create the DataFrame
health_data = pd.DataFrame(data, index=index, columns=columns)
health_data

Will give you table like this:

enter image description here

Standard access by column

health_data['Bob']
type       HR   Temp
year visit      
2013    1   22.0    38.6
        2   52.0    38.3
2014    1   30.0    38.9
        2   31.0    37.3


health_data['Bob']['HR']
year  visit
2013  1        22.0
      2        52.0
2014  1        30.0
      2        31.0
Name: HR, dtype: float64

# filtering by column/subcolumn - your case:
health_data['Bob']['HR']==22
year  visit
2013  1         True
      2        False
2014  1        False
      2        False

health_data['Bob']['HR'][2013]    
visit
1    22.0
2    52.0
Name: HR, dtype: float64

health_data['Bob']['HR'][2013][1]
22.0

Access by row

health_data.loc[2013]
subject Bob Guido   Sue
type    HR  Temp    HR  Temp    HR  Temp
visit                       
1   22.0    38.6    40.0    38.9    53.0    37.5
2   52.0    38.3    42.0    34.6    30.0    37.7

health_data.loc[2013,1] 
subject  type
Bob      HR      22.0
         Temp    38.6
Guido    HR      40.0
         Temp    38.9
Sue      HR      53.0
         Temp    37.5
Name: (2013, 1), dtype: float64

health_data.loc[2013,1]['Bob']
type
HR      22.0
Temp    38.6
Name: (2013, 1), dtype: float64

health_data.loc[2013,1]['Bob']['HR']
22.0

Slicing multi-index

idx=pd.IndexSlice
health_data.loc[idx[:,1], idx[:,'HR']]
    subject Bob Guido   Sue
type    HR  HR  HR
year    visit           
2013    1   22.0    40.0    53.0
2014    1   30.0    52.0    45.0

What causes imported Maven project in Eclipse to use Java 1.5 instead of Java 1.6 by default and how can I ensure it doesn't?

I added this to my pom.xml below the project description and it worked:

<properties>
    <maven.compiler.source>1.6</maven.compiler.source>
    <maven.compiler.target>1.6</maven.compiler.target>
</properties>

How to zoom in/out an UIImage object when user pinches screen?

Keep in mind that you're NEVER zooming in on a UIImage. EVER.

Instead, you're zooming in and out on the view that displays the UIImage.

In this particular case, you chould choose to create a custom UIView with custom drawing to display the image, a UIImageView which displays the image for you, or a UIWebView which will need some additional HTML to back it up.

In all cases, you'll need to implement touchesBegan, touchesMoved, and the like to determine what the user is trying to do (zoom, pan, etc.).

ORA-00060: deadlock detected while waiting for resource

I was recently struggling with a similar problem. It turned out that the database was missing indexes on foreign keys. That caused Oracle to lock many more records than required which quickly led to a deadlock during high concurrency.

Here is an excellent article with lots of good detail, suggestions, and details about how to fix a deadlock: http://www.oratechinfo.co.uk/deadlocks.html#unindex_fk

Mipmap drawables for icons

If you build an APK for a target screen resolution like HDPI, the Android asset packageing tool,AAPT,can strip out the drawables for other resolution you don’t need.But if it’s in the mipmap folder,then these assets will stay in the APK, regardless of the target resolution.

CASE in WHERE, SQL Server

You can simplify to:

WHERE a.Country = COALESCE(NULLIF(@Country,0), a.Country);

How to use jquery $.post() method to submit form values

Yor $.post has no data. You need to pass the form data. You can use serialize() to post the form data. Try this

$("#post-btn").click(function(){
    $.post("process.php", $('#reg-form').serialize() ,function(data){
        alert(data);
    });
});

How to print Unicode character in C++?

This code works in Linux (C++11, geany, g++ 7.4.0):

#include <iostream>

using namespace std;


int utf8_to_unicode(string utf8_code);
string unicode_to_utf8(int unicode);


int main()
{
    cout << unicode_to_utf8(36) << '\t';
    cout << unicode_to_utf8(162) << '\t';
    cout << unicode_to_utf8(8364) << '\t';
    cout << unicode_to_utf8(128578) << endl;

    cout << unicode_to_utf8(0x24) << '\t';
    cout << unicode_to_utf8(0xa2) << '\t';
    cout << unicode_to_utf8(0x20ac) << '\t';
    cout << unicode_to_utf8(0x1f642) << endl;

    cout << utf8_to_unicode("$") << '\t';
    cout << utf8_to_unicode("¢") << '\t';
    cout << utf8_to_unicode("€") << '\t';
    cout << utf8_to_unicode("") << endl;

    cout << utf8_to_unicode("\x24") << '\t';
    cout << utf8_to_unicode("\xc2\xa2") << '\t';
    cout << utf8_to_unicode("\xe2\x82\xac") << '\t';
    cout << utf8_to_unicode("\xf0\x9f\x99\x82") << endl;

    return 0;
}


int utf8_to_unicode(string utf8_code)
{
    unsigned utf8_size = utf8_code.length();
    int unicode = 0;

    for (unsigned p=0; p<utf8_size; ++p)
    {
        int bit_count = (p? 6: 8 - utf8_size - (utf8_size == 1? 0: 1)),
            shift = (p < utf8_size - 1? (6*(utf8_size - p - 1)): 0);

        for (int k=0; k<bit_count; ++k)
            unicode += ((utf8_code[p] & (1 << k)) << shift);
    }

    return unicode;
}


string unicode_to_utf8(int unicode)
{
    string s;

    if (unicode>=0 and unicode <= 0x7f)  // 7F(16) = 127(10)
    {
        s = static_cast<char>(unicode);

        return s;
    }
    else if (unicode <= 0x7ff)  // 7FF(16) = 2047(10)
    {
        unsigned char c1 = 192, c2 = 128;

        for (int k=0; k<11; ++k)
        {
            if (k < 6)  c2 |= (unicode % 64) & (1 << k);
            else c1 |= (unicode >> 6) & (1 << (k - 6));
        }

        s = c1;    s += c2;

        return s;
    }
    else if (unicode <= 0xffff)  // FFFF(16) = 65535(10)
    {
        unsigned char c1 = 224, c2 = 128, c3 = 128;

        for (int k=0; k<16; ++k)
        {
            if (k < 6)  c3 |= (unicode % 64) & (1 << k);
            else if (k < 12) c2 |= (unicode >> 6) & (1 << (k - 6));
            else c1 |= (unicode >> 12) & (1 << (k - 12));
        }

        s = c1;    s += c2;    s += c3;

        return s;
    }
    else if (unicode <= 0x1fffff)  // 1FFFFF(16) = 2097151(10)
    {
        unsigned char c1 = 240, c2 = 128, c3 = 128, c4 = 128;

        for (int k=0; k<21; ++k)
        {
            if (k < 6)  c4 |= (unicode % 64) & (1 << k);
            else if (k < 12) c3 |= (unicode >> 6) & (1 << (k - 6));
            else if (k < 18) c2 |= (unicode >> 12) & (1 << (k - 12));
            else c1 |= (unicode >> 18) & (1 << (k - 18));
        }

        s = c1;    s += c2;    s += c3;    s += c4;

        return s;
    }
    else if (unicode <= 0x3ffffff)  // 3FFFFFF(16) = 67108863(10)
    {
        ;  // actually, there are no 5-bytes unicodes
    }
    else if (unicode <= 0x7fffffff)  // 7FFFFFFF(16) = 2147483647(10)
    {
        ;  // actually, there are no 6-bytes unicodes
    }
    else  ;  // incorrect unicode (< 0 or > 2147483647)

    return "";
}

More:

How do I sort a list of dictionaries by a value of the dictionary?

import operator
a_list_of_dicts.sort(key=operator.itemgetter('name'))

'key' is used to sort by an arbitrary value and 'itemgetter' sets that value to each item's 'name' attribute.

Count number of occurrences by month

Sooooo, I had this same question. here's my answer: COUNTIFS(sheet1!$A:$A,">="&D1,sheet1!$A:$A,"<="&D2)

you don't need to specify A2:A50, unless there are dates beyond row 50 that you wish to exclude. this is cleaner in the sense that you don't have to go back and adjust the rows as more PO data comes in on sheet1.

also, the reference to D1 and D2 are start and end dates (respectively) for each month. On sheet2, you could have a hidden column that translates April to 4/1/2014, May into 5/1/2014, etc. THen, D1 would reference the cell that contains 4/1/2014, and D2 would reference the cell that contains 5/1/2014.

if you want to sum, it works the same way, except that the first argument is the sum array (column or row) and then the rest of the ranges/arrays and arguments are the same as the countifs formula.

btw-this works in excel AND google sheets. cheers

How to make HTML input tag only accept numerical values?

The accepted answer:

function isNumberKey(evt){
    var charCode = (evt.which) ? evt.which : event.keyCode
    if (charCode > 31 && (charCode < 48 || charCode > 57))
        return false;
    return true;
}

It's good but not perfect. It works out for me, but i get a warning that the if-statement can be simplified.

Then it looks like this, which is way prettier:

function isNumberKey(evt){
    var charCode = (evt.which) ? evt.which : event.keyCode;
    return !(charCode > 31 && (charCode < 48 || charCode > 57));
}

Would comment the original post, but my reputation is too low to do so (just created this account).

How to produce an csv output file from stored procedure in SQL Server

Found a really helpful link for that. Using SQLCMD for this is really easier than solving this with a stored procedure

http://www.excel-sql-server.com/sql-server-export-to-excel-using-bcp-sqlcmd-csv.htm

Declare a variable as Decimal

The best way is to declare the variable as a Single or a Double depending on the precision you need. The data type Single utilizes 4 Bytes and has the range of -3.402823E38 to 1.401298E45. Double uses 8 Bytes.

You can declare as follows:

Dim decAsdf as Single

or

Dim decAsdf as Double

Here is an example which displays a message box with the value of the variable after calculation. All you have to do is put it in a module and run it.

Sub doubleDataTypeExample()
Dim doubleTest As Double


doubleTest = 0.0000045 * 0.005 * 0.01

MsgBox "doubleTest = " & doubleTest
End Sub

Is there an upside down caret character?

I did subscript capital & bolded V. It works perfectly (although it takes some effort, if it needs to be done repetitively)

Syntax:

<sub><strong>v</strong></sub>

Output:
v

asp:TextBox ReadOnly=true or Enabled=false?

Another behaviour is that readonly = 'true' controls will fire events like click, buton Enabled = False controls will not.

How to map a composite key with JPA and Hibernate?

Let's take a simple example. Let's say two tables named test and customer are there described as:

create table test(
  test_id int(11) not null auto_increment,
  primary key(test_id));

create table customer(
  customer_id int(11) not null auto_increment,
  name varchar(50) not null,
  primary key(customer_id));

One more table is there which keeps the track of tests and customer:

create table tests_purchased(
  customer_id int(11) not null,
  test_id int(11) not null,
  created_date datetime not null,
  primary key(customer_id, test_id));

We can see that in the table tests_purchased the primary key is a composite key, so we will use the <composite-id ...>...</composite-id> tag in the hbm.xml mapping file. So the PurchasedTest.hbm.xml will look like:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
  "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
  "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>
  <class name="entities.PurchasedTest" table="tests_purchased">

    <composite-id name="purchasedTestId">
      <key-property name="testId" column="TEST_ID" />
      <key-property name="customerId" column="CUSTOMER_ID" />
    </composite-id>

    <property name="purchaseDate" type="timestamp">
      <column name="created_date" />
    </property>

  </class>
</hibernate-mapping>

But it doesn't end here. In Hibernate we use session.load (entityClass, id_type_object) to find and load the entity using primary key. In case of composite keys, the ID object should be a separate ID class (in above case a PurchasedTestId class) which just declares the primary key attributes like below:

import java.io.Serializable;

public class PurchasedTestId implements Serializable {
  private Long testId;
  private Long customerId;

  // an easy initializing constructor
  public PurchasedTestId(Long testId, Long customerId) {
    this.testId = testId;
    this.customerId = customerId;
  }

  public Long getTestId() {
    return testId;
  }

  public void setTestId(Long testId) {
    this.testId = testId;
  }

  public Long getCustomerId() {
    return customerId;
  }

  public void setCustomerId(Long customerId) {
    this.customerId = customerId;
  }

  @Override
  public boolean equals(Object arg0) {
    if(arg0 == null) return false;
    if(!(arg0 instanceof PurchasedTestId)) return false;
    PurchasedTestId arg1 = (PurchasedTestId) arg0;
    return (this.testId.longValue() == arg1.getTestId().longValue()) &&
           (this.customerId.longValue() == arg1.getCustomerId().longValue());
  }

  @Override
  public int hashCode() {
    int hsCode;
    hsCode = testId.hashCode();
    hsCode = 19 * hsCode+ customerId.hashCode();
    return hsCode;
  }
}

Important point is that we also implement the two functions hashCode() and equals() as Hibernate relies on them.

How to allow user to pick the image with Swift?

Of course, above answers solve the main problem.

I faced a crash in Swift 3.0 while launching the photo album because Info.plist did not had these flags:

  1. Privacy - Photo Library Usage Description -> NSPhotoLibraryUsageDescription

  2. Privacy - Camera Usage Description -> NSCameraUsageDescription

[screenshot[1]

Please add them if you face similar issue.

Thanks !

Pandas: drop a level from a multi-level column index?

As of Pandas 0.24.0, we can now use DataFrame.droplevel():

cols = pd.MultiIndex.from_tuples([("a", "b"), ("a", "c")])
df = pd.DataFrame([[1,2], [3,4]], columns=cols)

df.droplevel(0, axis=1) 

#   b  c
#0  1  2
#1  3  4

This is very useful if you want to keep your DataFrame method-chain rolling.

How to check undefined in Typescript

It actually is working, but there is difference between null and undefined. You are actually assigning to uemail, which would return a value or null in case it does not exists. As per documentation.

For more information about the difference between the both of them, see this answer.

For a solution to this Garfty's answer may work, depending on what your requirement is. You may also want to have a look here.

Facebook Oauth Logout

For Python developers that want to log user out straight from the backend

At the moment I'm writing this, the trick with m.facebook.com no longer works (at least for me) and user is redirected to the mobile FB login page which obviously is not good for UX.

Fortunately, FB PHP SDK has a semi-documented solution (in case the link doesn't lead to getLogoutUrl() function, just search look for it on that page). This is also mentioned in at least one other on StackOverflow: Facebook php SDK getLogoutUrl() problem.

BTW I've just noticed that Zach Greenberg got it right in this question, but I'm adding my answer as a summary for Python developers.

geom_smooth() what are the methods available?

The method argument specifies the parameter of the smooth statistic. You can see stat_smooth for the list of all possible arguments to the method argument.

How do you initialise a dynamic array in C++?

The array form of new-expression accepts only one form of initializer: an empty (). This, BTW, has the same effect as the empty {} in your non-dynamic initialization.


The above applies to pre-C++11 language. Starting from C++11 one can use uniform initialization syntax with array new-expressions

char* c = new char[length]{};
char* d = new char[length]{ 'a', 'b', 'c' };

The imported project "C:\Microsoft.CSharp.targets" was not found

I got this after reinstalling Windows. Visual Studio was installed, and I could see the Silverlight project type in the New Project window, but opening one didn't work. The solution was simple: I had to install the Silverlight Developer runtime and/or the Microsoft Silverlight 4 Tools for Visual Studio. This may seem stupid, but I overlooked it because I thought it should work, as the Silverlight project type was available.

How to Set Selected value in Multi-Value Select in Jquery-Select2.?

you can add the selected values in an array and set it as the value for default selection

eg:

var selectedItems =[];
selectedItems.push("your selected items");
..
$('#drp_Books_Ill_Illustrations').select2('val',selectedItems );

Try this, this should definitely work!

Copying a HashMap in Java

Since this question is still unanswered and I had a similar problem, I will try to answer this. The problem (as others already mentioned) is that you just copy references to the same object and thus a modify on the copy will also modify the origin object. So what you have to to is to copy the object (your map value) itself. The far easiest way to do so is to make all your objects implementing the serializeable interface. Then serialize and deserialize your map to get a real copy. You can do this by yourself or use the apache commons SerializationUtils#clone() which you can find here: https://commons.apache.org/proper/commons-lang/javadocs/api-2.6/org/apache/commons/lang/SerializationUtils.html But be aware this is the simplest approach but it is an expensive task to serialize and deserialize a lot of objects.

How to check if any flags of a flag combination are set?

There is HasFlag method in .NET 4 or higher.

if(letter.HasFlag(Letters.AB))
{
}

How to position a div scrollbar on the left hand side?

Here is what I have done to make the right scroll bar work. The only thing needed to be considered is when using 'direction: rtl' and whole table also need to be changed. Hopefully this gives you an idea how to do it.

Example:

<table dir='rtl'><tr><td>Display Last</td><td>Display Second</td><td>Display First</td></table>

Check this: JSFiddle

Capturing Groups From a Grep RegEx

This is a solution that uses gawk. It's something I find I need to use often so I created a function for it

function regex1 { gawk 'match($0,/'$1'/, ary) {print ary['${2:-'1'}']}'; }

to use just do

$ echo 'hello world' | regex1 'hello\s(.*)'
world

Change Button color onClick

1.

function setColor(e) {
  var target = e.target,
      count = +target.dataset.count;

   target.style.backgroundColor = count === 1 ? "#7FFF00" : '#FFFFFF';
   target.dataset.count = count === 1 ? 0 : 1;
   /* 

   () : ? - this is conditional (ternary) operator - equals 

   if (count === 1) {
      target.style.backgroundColor = "#7FFF00";
      target.dataset.count = 0;
   } else {
      target.style.backgroundColor = "#FFFFFF";
      target.dataset.count = 1;
   } 
   target.dataset - return all "data attributes" for current element, 
   in the form of object, 
   and you don't need use global variable in order to save the state 0 or 1
  */ 
}


<input 
  type="button" 
  id="button" 
  value="button" 
  style="color:white" 
  onclick="setColor(event)"; 
  data-count="1" 
/>

2.

function setColor(e) {
   var target = e.target,
       status = e.target.classList.contains('active');

   e.target.classList.add(status ? 'inactive' : 'active');
   e.target.classList.remove(status ? 'active' : 'inactive'); 
}

.active {
  background-color: #7FFF00;  
}

.inactive {
  background-color: #FFFFFF;
}

<input 
  type="button" 
  id="button" 
  value="button" 
  style="color:white" 
  onclick="setColor(event)" 
/>

([conditional (ternary) operator])

Example-1

Example-2

Removing NA observations with dplyr::filter()

For example:

you can use:

df %>% filter(!is.na(a))

to remove the NA in column a.

Using member variable in lambda capture list inside a member function

Summary of the alternatives:

capture this:

auto lambda = [this](){};

use a local reference to the member:

auto& tmp = grid;
auto lambda = [ tmp](){}; // capture grid by (a single) copy
auto lambda = [&tmp](){}; // capture grid by ref

C++14:

auto lambda = [ grid = grid](){}; // capture grid by copy
auto lambda = [&grid = grid](){}; // capture grid by ref

example: https://godbolt.org/g/dEKVGD

Concatenate two PySpark dataframes

Above answers are very elegant. I have written this function long back where i was also struggling to concatenate two dataframe with distinct columns.

Suppose you have dataframe sdf1 and sdf2

from pyspark.sql import functions as F
from pyspark.sql.types import *

def unequal_union_sdf(sdf1, sdf2):
    s_df1_schema = set((x.name, x.dataType) for x in sdf1.schema)
    s_df2_schema = set((x.name, x.dataType) for x in sdf2.schema)

    for i,j in s_df2_schema.difference(s_df1_schema):
        sdf1 = sdf1.withColumn(i,F.lit(None).cast(j))

    for i,j in s_df1_schema.difference(s_df2_schema):
        sdf2 = sdf2.withColumn(i,F.lit(None).cast(j))

    common_schema_colnames = sdf1.columns
    sdk = \
        sdf1.select(common_schema_colnames).union(sdf2.select(common_schema_colnames))
    return sdk 

sdf_concat = unequal_union_sdf(sdf1, sdf2) 

CSS background-image not working

I faced this problem. My html was as below:

<th style="background-image:url('Image.png');">
</th>

I added "&nbsp" as @shankhan suggested inside th and the image started showing up.

<th style="background-image:url('Image.png');">
   &nbsp;
</th>

Do you have to include <link rel="icon" href="favicon.ico" type="image/x-icon" />?

If you don't call the favicon, favicon.ico, you can use that tag to specify the actual path (incase you have it in an images/ directory). The browser/webpage looks for favicon.ico in the root directory by default.

Where's the IE7/8/9/10-emulator in IE11 dev tools?

I posted an answer to this already when someone else asked the same question (see How to bring back "Browser mode" in IE11?).

Read my answer there for a fuller explaination, but in short:

  • They removed it deliberately, because compat mode is not actually really very good for testing compatibility.

  • If you really want to test for compatibility with any given version of IE, you need to test in a real copy of that IE version. MS provide free VMs on http://modern.ie/ for you to use for this purpose.

  • The only way to get compat mode in IE11 is to set the X-UA-Compatible header. When you have this and the site defaults to compat mode, you will be able to set the mode in dev tools, but only between edge or the specified compat mode; other modes will still not be available.

PHP: HTTP or HTTPS?

If the request was sent with HTTPS you will have a extra parameter in the $_SERVER superglobal - $_SERVER['HTTPS']. You can check if it is set or not

if( isset($_SERVER['HTTPS'] ) ) {

HTTP headers in Websockets client API

Technically, you will be sending these headers through the connect function before the protocol upgrade phase. This worked for me in a nodejs project:

var WebSocketClient = require('websocket').client;
var ws = new WebSocketClient();
ws.connect(url, '', headers);

What is the difference between Trap and Interrupt?

A trap is called by code like programs and used e. g. to call OS routines (i. e. normally synchronous). An interrupt is called by events (many times hardware, like the network card having received data, or the CPU timer), and - as the name suggests - interrupts the normal control flow, as the CPU has to switch to the driver routine to handle the event.

How to git ignore subfolders / subdirectories?

Seems this page still shows up on the top of Google search after so many years...

Modern versions of Git support nesting .gitignore files within a single repo. Just place a .gitignore file in the subdirectory that you want ignored. Use a single asterisk to match everything in that directory:

echo "*" > /path/to/bin/Debug/.gitignore
echo "*" > /path/to/bin/Release/.gitignore

If you've made previous commits, remember to remove previously tracked files:

git rm -rf /path/to/bin/Debug
git rm -rf /path/to/bin/Release

You can confirm it by doing git status to show you all the files removed from tracking.

Structuring online documentation for a REST API

That's a very complex question for a simple answer.

You may want to take a look at existing API frameworks, like Swagger Specification (OpenAPI), and services like apiary.io and apiblueprint.org.

Also, here's an example of the same REST API described, organized and even styled in three different ways. It may be a good start for you to learn from existing common ways.

At the very top level I think quality REST API docs require at least the following:

  • a list of all your API endpoints (base/relative URLs)
  • corresponding HTTP GET/POST/... method type for each endpoint
  • request/response MIME-type (how to encode params and parse replies)
  • a sample request/response, including HTTP headers
  • type and format specified for all params, including those in the URL, body and headers
  • a brief text description and important notes
  • a short code snippet showing the use of the endpoint in popular web programming languages

Also there are a lot of JSON/XML-based doc frameworks which can parse your API definition or schema and generate a convenient set of docs for you. But the choice for a doc generation system depends on your project, language, development environment and many other things.

Which tool to build a simple web front-end to my database

I think PHP is a good solution. It's simple to set up, free and there is plenty of documentation on how to create a database management app. Ruby on Rails is faster to code but a bit more difficult to set up.

How to set upload_max_filesize in .htaccess?

If you are getting 500 - Internal server error that means you don't have permission to set these values by .htaccess. You have to contact your web server providers and ask to set AllowOverride Options for your host or to put these lines in their virtual host configuration file.

Node: log in a file instead of the console

You could also just overload the default console.log function:

var fs = require('fs');
var util = require('util');
var log_file = fs.createWriteStream(__dirname + '/debug.log', {flags : 'w'});
var log_stdout = process.stdout;

console.log = function(d) { //
  log_file.write(util.format(d) + '\n');
  log_stdout.write(util.format(d) + '\n');
};

Above example will log to debug.log and stdout.

Edit: See multiparameter version by Clément also on this page.

How to run an android app in background?

As apps run in the background anyway. I’m assuming what your really asking is how do you make apps do stuff in the background. The solution below will make your app do stuff in the background after opening the app and after the system has rebooted.

Below, I’ve added a link to a fully working example (in the form of an Android Studio Project)

This subject seems to be out of the scope of the Android docs, and there doesn’t seem to be any one comprehensive doc on this. The information is spread across a few docs.

The following docs tell you indirectly how to do this: https://developer.android.com/reference/android/app/Service.html

https://developer.android.com/reference/android/content/BroadcastReceiver.html

https://developer.android.com/guide/components/bound-services.html

In the interests of getting your usage requirements correct, the important part of this above doc to read carefully is: #Binder, #Messenger and the components link below:

https://developer.android.com/guide/components/aidl.html

Here is the link to a fully working example (in Android Studio format): http://developersfound.com/BackgroundServiceDemo.zip

This project will start an Activity which binds to a service; implementing the AIDL.

This project is also useful to re-factor for the purpose of IPC across different apps.

This project is also developed to start automatically when Android restarts (provided the app has been run at least one after installation and app is not installed on SD card)

When this app/project runs after reboot, it dynamically uses a transparent view to make it look like no app has started but the service of the associated app starts cleanly.

This code is written in such a way that it’s very easy to tweak to simulate a scheduled service.

This project is developed in accordance to the above docs and is subsequently a clean solution.

There is however a part of this project which is not clean being: I have not found a way to start a service on reboot without using an Activity. If any of you guys reading this post have a clean way to do this please post a comment.

Preventing iframe caching in browser

I set iframe src attribute later in my app. To get rid of the cached content inside iframe at the start of the application I simply do:

myIframe.src = "";

... somewhere in the beginning of js code (for instance in jquery $() handler)

Thanks to http://www.freshsupercool.com/2008/07/10/firefox-caching-iframe-data/