Programs & Examples On #Initialization list

Initialisation lists are used to initialise class members in other than default manner. This is usually used in cases where class member is a class instance.

C++: Where to initialize variables in constructor

There are many other reasons. You should always initialize all member variables in the initialization list if possible.

http://www.parashift.com/c++-faq-lite/ctors.html#faq-10.6

Android Studio-No Module

Other path is " tool menu-->android-->sync proyect with gradle File"

Calling a parent window function from an iframe

I have posted this as a separate answer as it is unrelated to my existing answer.

This issue recently cropped up again for accessing a parent from an iframe referencing a subdomain and the existing fixes did not work.

This time the answer was to modify the document.domain of the parent page and the iframe to be the same. This will fool the same origin policy checks into thinking they co-exist on exactly the same domain (subdomains are considered a different host and fail the same origin policy check).

Insert the following to the <head> of the page in the iframe to match the parent domain (adjust for your doctype).

<script>
    document.domain = "mydomain.com";
</script>

Please note that this will throw an error on localhost development, so use a check like the following to avoid the error:

if (!window.location.href.match(/localhost/gi)) {
    document.domain = "mydomain.com";
} 

Select second last element with css

In CSS3 you have:

:nth-last-child(2)

See: https://developer.mozilla.org/en-US/docs/Web/CSS/:nth-last-child

nth-last-child Browser Support:

  • Chrome 2
  • Firefox 3.5
  • Opera 9.5, 10
  • Safari 3.1, 4
  • Internet Explorer 9

Cassandra cqlsh - connection refused

You need to edit cassandra.yaml on the node you are trying to connect to and set the node ip address for rpc_address and listen_address and restart Cassandra.

rpc_address is the address on which Cassandra listens to the client calls.

listen_address is the address on which Cassandra listens to the other Cassandra nodes.

'Microsoft.ACE.OLEDB.16.0' provider is not registered on the local machine. (System.Data)

Follow these steps:

  1. Go [here][1], download Microsoft Access Database Engine 2016 Redistributable and install
  2. Close SQL Server Management Studio
  3. Go to Start Menu -> Microsoft SQL Server 2017 -> SQL Server 2017 Import and Export Data (64-bit)
  4. Open the application and try to import data using the "Excel 2016" option, it should work fine.

How can I convert a dictionary into a list of tuples?

A simpler one would be

list(dictionary.items())  # list of (key, value) tuples
list(zip(dictionary.values(), dictionary.keys()))  # list of (key, value) tuples

How do you get a directory listing sorted by creation date in python?

this is a basic step for learn:

import os, stat, sys
import time

dirpath = sys.argv[1] if len(sys.argv) == 2 else r'.'

listdir = os.listdir(dirpath)

for i in listdir:
    os.chdir(dirpath)
    data_001 = os.path.realpath(i)
    listdir_stat1 = os.stat(data_001)
    listdir_stat2 = ((os.stat(data_001), data_001))
    print time.ctime(listdir_stat1.st_ctime), data_001

jQuery adding 2 numbers from input fields

There are two way that you can add two number in jQuery

First way:

var x = parseInt(a) + parseInt(b);
alert(x);

Second Way:

var x = parseInt(a+2);
alert(x);

Now come your question

var a = parseInt($("#a").val()); 
var b = parseInt($("#b").val());
alert(a+b);

Correct way to focus an element in Selenium WebDriver using Java

The following code -

element.sendKeys("");

tries to find an input tag box to enter some information, while

new Actions(driver).moveToElement(element).perform();

is more appropriate as it will work for image elements, link elements, dropdown boxes etc.

Therefore using moveToElement() method makes more sense to focus on any generic WebElement on the web page.

For an input box you will have to click() on the element to focus.

new Actions(driver).moveToElement(element).click().perform();

while for links and images the mouse will be over that particular element,you can decide to click() on it depending on what you want to do.

If the click() on an input tag does not work -

Since you want this function to be generic, you first check if the webElement is an input tag or not by -

if("input".equals(element.getTagName()){
   element.sendKeys("");
} 
else{
   new Actions(driver).moveToElement(element).perform();

}

You can make similar changes based on your preferences.

Why do you need to put #!/bin/bash at the beginning of a script file?

Every distribution has a default shell. Bash is the default on the majority of the systems. If you happen to work on a system that has a different default shell, then the scripts might not work as intended if they are written specific for Bash.

Bash has evolved over the years taking code from ksh and sh.

Adding #!/bin/bash as the first line of your script, tells the OS to invoke the specified shell to execute the commands that follow in the script.

#! is often referred to as a "hash-bang", "she-bang" or "sha-bang".

How to copy static files to build directory with Webpack?

Above suggestions are good. But to try to answer your question directly I'd suggest using cpy-cli in a script defined in your package.json.

This example expects node to somewhere on your path. Install cpy-cli as a development dependency:

npm install --save-dev cpy-cli

Then create a couple of nodejs files. One to do the copy and the other to display a checkmark and message.

copy.js

#!/usr/bin/env node

var shelljs = require('shelljs');
var addCheckMark = require('./helpers/checkmark');
var path = require('path');

var cpy = path.join(__dirname, '../node_modules/cpy-cli/cli.js');

shelljs.exec(cpy + ' /static/* /build/', addCheckMark.bind(null, callback));

function callback() {
  process.stdout.write(' Copied /static/* to the /build/ directory\n\n');
}

checkmark.js

var chalk = require('chalk');

/**
 * Adds mark check symbol
 */
function addCheckMark(callback) {
  process.stdout.write(chalk.green(' ?'));
  callback();
}

module.exports = addCheckMark;

Add the script in package.json. Assuming scripts are in <project-root>/scripts/

...
"scripts": {
  "copy": "node scripts/copy.js",
...

To run the sript:

npm run copy

Converting Milliseconds to Minutes and Seconds?

I would suggest using TimeUnit. You can use it like this:

long minutes = TimeUnit.MILLISECONDS.toMinutes(millis);
long seconds = TimeUnit.MILLISECONDS.toSeconds(millis);

How to preview git-pull without doing fetch?

You can fetch from a remote repo, see the differences and then pull or merge.

This is an example for a remote repo called origin and a branch called master tracking the remote branch origin/master:

git checkout master                                                  
git fetch                                        
git diff origin/master
git pull --rebase origin master

Set Content-Type to application/json in jsp file

@Petr Mensik & kensen john

Thanks, I could not used the page directive because I have to set a different content type according to some URL parameter. I will paste my code here since it's something quite common with JSON:

    <%
        String callback = request.getParameter("callback");
        response.setCharacterEncoding("UTF-8");
        if (callback != null) {
            // Equivalent to: <@page contentType="text/javascript" pageEncoding="UTF-8">
            response.setContentType("text/javascript");
        } else {
            // Equivalent to: <@page contentType="application/json" pageEncoding="UTF-8">
            response.setContentType("application/json");
        }

        [...]

        String output = "";

        if (callback != null) {
            output += callback + "(";
        }

        output += jsonObj.toString();

        if (callback != null) {
            output += ");";
        }
    %>
    <%=output %>

When callback is supplied, returns:

    callback({...JSON stuff...});

with content-type "text/javascript"

When callback is NOT supplied, returns:

    {...JSON stuff...}

with content-type "application/json"

How to get the Development/Staging/production Hosting Environment in ConfigureServices

Just in case someone is looking to this too. In .net core 3+ most of this is obsolete. The update way is:

public void Configure(
    IApplicationBuilder app,
    IWebHostEnvironment env,
    ILogger<Startup> logger)
{
    if (env.EnvironmentName == Environments.Development)
    {
        // logger.LogInformation("In Development environment");
    }
}

Error: 10 $digest() iterations reached. Aborting! with dynamic sortby predicate

It's weird ... I've got the exact same error, coming from a different thing. When I create my controller I passed the $location parameter, like this :

App.controller('MessageController', function ($scope, $http, $log, $location, $attrs, MessageFactory, SocialMessageFactory) {
   // controller code
});

This was proven to be a bug when we use third party libraries or pure JS to manipulate some specifics (here window.location) the next digest of angular will blow this error.

So I simply removed the $location from the controller creation parameter, and it worked again, without this error. Or if you absolutely need to use the $location from angular, you have to remove every single <a href="#">link</a> in the links of your template page, and rather write href="". Worked for me.

Hope it can help one day.

Decimal values in SQL for dividing results

Just another approach:

SELECT col1 * 1.0 / col2 FROM tbl1

Multiplying by 1.0 turns an integer into a float numeric(13,1) and so works like a typecast, but most probably it is slower than that.

A slightly shorter variation suggested by Aleksandr Fedorenko in a comment:

SELECT col1 * 1. / col2 FROM tbl1

The effect would be basically the same. The only difference is that the multiplication result in this case would be numeric(12,0).

Principal advantage: less wordy than other approaches.

Exposing a port on a live Docker container

To add to the accepted answer iptables solution, I had to run two more commands on the host to open it to the outside world.

HOST> iptables -t nat -A DOCKER -p tcp --dport 443 -j DNAT --to-destination 172.17.0.2:443
HOST> iptables -t nat -A POSTROUTING -j MASQUERADE -p tcp --source 172.17.0.2 --destination 172.17.0.2 --dport https
HOST> iptables -A DOCKER -j ACCEPT -p tcp --destination 172.17.0.2 --dport https

Note: I was opening port https (443), my docker internal IP was 172.17.0.2

Note 2: These rules and temporrary and will only last until the container is restarted

Excel 2013 horizontal secondary axis

You should follow the guidelines on Add a secondary horizontal axis:

Add a secondary horizontal axis

To complete this procedure, you must have a chart that displays a secondary vertical axis. To add a secondary vertical axis, see Add a secondary vertical axis.

  1. Click a chart that displays a secondary vertical axis. This displays the Chart Tools, adding the Design, Layout, and Format tabs.

  2. On the Layout tab, in the Axes group, click Axes.

    enter image description here

  3. Click Secondary Horizontal Axis, and then click the display option that you want.

enter image description here


Add a secondary vertical axis

You can plot data on a secondary vertical axis one data series at a time. To plot more than one data series on the secondary vertical axis, repeat this procedure for each data series that you want to display on the secondary vertical axis.

  1. In a chart, click the data series that you want to plot on a secondary vertical axis, or do the following to select the data series from a list of chart elements:

    • Click the chart.

      This displays the Chart Tools, adding the Design, Layout, and Format tabs.

    • On the Format tab, in the Current Selection group, click the arrow in the Chart Elements box, and then click the data series that you want to plot along a secondary vertical axis.

      enter image description here

  2. On the Format tab, in the Current Selection group, click Format Selection. The Format Data Series dialog box is displayed.

    Note: If a different dialog box is displayed, repeat step 1 and make sure that you select a data series in the chart.

  3. On the Series Options tab, under Plot Series On, click Secondary Axis and then click Close.

    A secondary vertical axis is displayed in the chart.

  4. To change the display of the secondary vertical axis, do the following:

    • On the Layout tab, in the Axes group, click Axes.

    • Click Secondary Vertical Axis, and then click the display option that you want.

  5. To change the axis options of the secondary vertical axis, do the following:

    • Right-click the secondary vertical axis, and then click Format Axis.

    • Under Axis Options, select the options that you want to use.

Configure hibernate to connect to database via JNDI Datasource

I was getting the same error in my IBM Websphere with c3p0 jar files. I have Oracle 10g database. I simply added the oraclejdbc.jar files in the Application server JVM in IBM Classpath using Websphere Console and the error was resolved.

The oraclejdbc.jar should be set with your C3P0 jar files in your Server Class path whatever it be tomcat, glassfish of IBM.

Why I've got no crontab entry on OS X when using vim?

In user crontab (crontab -e) do not put the user field.

Correct cron is:

0-59 * * * * echo "Hello World"

Syntax with user field is for /etc/crontab only:

0-59 * * * * mollerhoj3 echo "Hello World"

How to add Action bar options menu in Android Fragments

I am late for the answer but I think this is another solution which is not mentioned here so posting.

Step 1: Make a xml of menu which you want to add like I have to add a filter action on my action bar so I have created a xml filter.xml. The main line to notice is android:orderInCategory this will show the action icon at first or last wherever you want to show. One more thing to note down is the value, if the value is less then it will show at first and if value is greater then it will show at last.

filter.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools" >


    <item
        android:id="@+id/action_filter"
        android:title="@string/filter"
        android:orderInCategory="10"
        android:icon="@drawable/filter"
        app:showAsAction="ifRoom" />


</menu>

Step 2: In onCreate() method of fragment just put the below line as mentioned, which is responsible for calling back onCreateOptionsMenu(Menu menu, MenuInflater inflater) method just like in an Activity.

@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setHasOptionsMenu(true);
    }

Step 3: Now add the method onCreateOptionsMenu which will be override as:

@Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        inflater.inflate(R.menu.filter, menu);  // Use filter.xml from step 1
    }

Step 4: Now add onOptionsItemSelected method by which you can implement logic whatever you want to do when you select the added action icon from actionBar:

@Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        if(id == R.id.action_filter){
            //Do whatever you want to do 
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

Unsupported major.minor version 52.0

I could solve the same problem using the below solution.

In my project, I added a JAR file which were created in Java 8. And my project was referring to JRE 7. When I changed project JRE to 8, my problem was solved.

Steps:

In Eclipse, right click on the project name in project explorer ? Build path ? Libraries ? click on JRE version ? click Edit ? Installed JRE ? Add ? Standerd VM ? select JRE home click-path (path should be localePath\java\jdk1.8.0_25\jre) ? provide name ? Save ? select same JRE for project ? Finish ? OK. Refresh/build project once ? try to run your Java file. It should work.

Connecting to smtp.gmail.com via command line

Gmail require SMTP communication with their server to be encrypted. Although you're opening up a connection to Gmail's server on port 465, unfortunately you won't be able to communicate with it in plaintext as Gmail require you to use STARTTLS/SSL encryption for the connection.

AndroidStudio SDK directory does not exists

Just open your local.property file

if your project is used in mac before, so the sdk path will be something like sdk.dir=/Users/siddharthyadav/Library/Android/

Now if you are trying to use that in windows so just edit and put your sdk location: Example: sdk.dir=D:\software\android-sdk\android-sdk

Just clean and build. See it works!!!

WebView and HTML5 <video>

mdelolmo's answer was incredibly helpful, but like he said, the video only plays once and then you can't open it again.

I looked into this a bit and here is what I found, in case any weary WebView travelers like myself stumble on this post in the future.

First off, I looked at the VideoView and MediaPlayer's documentation and got a better sense of how those work. I strongly recommend those.

Then, I looked at the source code to see how the Android Browser does it. Do a page find and go look at how they handle onShowCustomView(). They keep a reference to the CustomViewCallbackand to the custom view.

With all of that, and with mdelolmo's answer in mind, when you are done with the video, all you need to do is two things. First, on the VideoView that you saved a reference to, call stopPlayback() that will release the MediaPlayer to be used later elsewhere. You can see it in the VideoView source code. Second, on the CustomViewCallback you saved a reference to call CustomViewCallback.onCustomViewHidden().

After doing those two things, you can click on the same video or any other video and it will open like before. No need to restart the entire WebView.

Hope that helps.

Copy tables from one database to another in SQL Server

If it’s one table only then all you need to do is

  • Script table definition
  • Create new table in another database
  • Update rules, indexes, permissions and such
  • Import data (several insert into examples are already shown above)

One thing you’ll have to consider is other updates such as migrating other objects in the future. Note that your source and destination tables do not have the same name. This means that you’ll also have to make changes if you dependent objects such as views, stored procedures and other.

Whit one or several objects you can go manually w/o any issues. However, when there are more than just a few updates 3rd party comparison tools come in very handy. Right now I’m using ApexSQL Diff for schema migrations but you can’t go wrong with any other tool out there.

How to run (not only install) an android application using .apk file?

You can't install and run in one go - but you can certainly use adb to start your already installed application. Use adb shell am start to fire an intent - you will need to use the correct intent for your application though. A couple of examples:

adb shell am start -a android.intent.action.MAIN -n com.android.settings/.Settings 

will launch Settings, and

adb shell am start -a android.intent.action.MAIN -n com.android.browser/.BrowserActivity 

will launch the Browser. If you want to point the Browser at a particular page, do this

adb shell am start -a android.intent.action.VIEW -n com.android.browser/.BrowserActivity http://www.google.co.uk

If you don't know the name of the activities in the APK, then do this

aapt d xmltree <path to apk> AndroidManifest.xml

the output content will includes a section like this:

   E: activity (line=32)
    A: android:theme(0x01010000)=@0x7f080000
    A: android:label(0x01010001)=@0x7f070000
    A: android:name(0x01010003)="com.anonymous.MainWindow"
    A: android:launchMode(0x0101001d)=(type 0x10)0x3
    A: android:screenOrientation(0x0101001e)=(type 0x10)0x1
    A: android:configChanges(0x0101001f)=(type 0x11)0x80
    E: intent-filter (line=33)
      E: action (line=34)
        A: android:name(0x01010003)="android.intent.action.MAIN"
        XE: (line=34)

That tells you the name of the main activity (MainWindow), and you can now run

adb shell am start -a android.intent.action.MAIN -n com.anonymous/.MainWindow

How to add url parameter to the current url?

If you wish to use "like" as a parameter your link needs to be:

<a href="/topic.php?like=like">Like</a>

More likely though is that you want:

<a href="/topic.php?id=14&like=like">Like</a>

How to find event listeners on a DOM node when debugging or from the JavaScript code?

I was recently working with events and wanted to view/control all events in a page. Having looked at possible solutions, I've decided to go my own way and create a custom system to monitor events. So, I did three things.

First, I needed a container for all the event listeners in the page: that's theEventListeners object. It has three useful methods: add(), remove(), and get().

Next, I created an EventListener object to hold the necessary information for the event, i.e.: target, type, callback, options, useCapture, wantsUntrusted, and added a method remove() to remove the listener.

Lastly, I extended the native addEventListener() and removeEventListener() methods to make them work with the objects I've created (EventListener and EventListeners).

Usage:

var bodyClickEvent = document.body.addEventListener("click", function () {
    console.log("body click");
});

// bodyClickEvent.remove();

addEventListener() creates an EventListener object, adds it to EventListeners and returns the EventListener object, so it can be removed later.

EventListeners.get() can be used to view the listeners in the page. It accepts an EventTarget or a string (event type).

// EventListeners.get(document.body);
// EventListeners.get("click");

Demo

Let's say we want to know every event listener in this current page. We can do that (assuming you're using a script manager extension, Tampermonkey in this case). Following script does this:

// ==UserScript==
// @name         New Userscript
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  try to take over the world!
// @author       You
// @include      https://stackoverflow.com/*
// @grant        none
// ==/UserScript==

(function() {
    fetch("https://raw.githubusercontent.com/akinuri/js-lib/master/EventListener.js")
        .then(function (response) {
            return response.text();
        })
        .then(function (text) {
            eval(text);
            window.EventListeners = EventListeners;
        });
})(window);

And when we list all the listeners, it says there are 299 event listeners. There "seems" to be some duplicates, but I don't know if they're really duplicates. Not every event type is duplicated, so all those "duplicates" might be an individual listener.

screenshot of console listing all event listeners in this page

Code can be found at my repository. I didn't want to post it here because it's rather long.


Update: This doesn't seem to work with jQuery. When I examine the EventListener, I see that the callback is

function(b){return"undefined"!=typeof r&&r.event.triggered!==b.type?r.event.dispatch.apply(a,arguments):void 0}

I believe this belongs to jQuery, and is not the actual callback. jQuery stores the actual callback in the properties of the EventTarget:

$(document.body).click(function () {
    console.log("jquery click");
});

enter image description here

To remove an event listener, the actual callback needs to be passed to the removeEventListener() method. So in order to make this work with jQuery, it needs further modification. I might fix that in the future.

Why use multiple columns as primary keys (composite primary key)

Multiple columns in a key are going to, in general, perform more poorly than a surrogate key. I prefer to have a surrogate key and then a unique index on a multicolumn key. That way you can have better performance and the uniqueness needed is maintained. And even better, when one of the values in that key changes, you don't also have to update a million child entries in 215 child tables.

How to load/edit/run/save text files (.py) into an IPython notebook cell?

Drag and drop a Python file in the Ipython notebooks "home" notebooks table, click upload. This will create a new notebook with only one cell containing your .py file content

Else copy/paste from your favorite editor ;)

How to uncheck a radio button?

Rewrite of Igor's code as plugin.

Use:

$('input[type=radio]').uncheckableRadio();

Plugin:

(function( $ ){

    $.fn.uncheckableRadio = function() {

        return this.each(function() {
            $(this).mousedown(function() {
                $(this).data('wasChecked', this.checked);
            });

            $(this).click(function() {
                if ($(this).data('wasChecked'))
                    this.checked = false;
            });
        });

    };

})( jQuery );

How to reload a page after the OK click on the Alert Page

Bojan Milic answer work in a way but it error out with a message below,

enter image description here

This can be avoid with,

function message() 
{
alert("Successful message");
window.location = 'url_Of_Redirected_Page' // i.e. window.location='default.aspx'
}

difference between css height : 100% vs height : auto

height: 100% gives the element 100% height of its parent container.

height: auto means the element height will depend upon the height of its children.

Consider these examples:

height: 100%

<div style="height: 50px">
    <div id="innerDiv" style="height: 100%">
    </div>
</div>

#innerDiv is going to have height: 50px

height: auto

<div style="height: 50px">
    <div id="innerDiv" style="height: auto">
          <div id="evenInner" style="height: 10px">
          </div>
    </div>
</div>

#innerDiv is going to have height: 10px

How do I obtain the frequencies of each value in an FFT?

The FFT output coefficients (for complex input of size N) are from 0 to N - 1 grouped as [LOW,MID,HI,HI,MID,LOW] frequency.

I would consider that the element at k has the same frequency as the element at N-k since for real data, FFT[N-k] = complex conjugate of FFT[k].

The order of scanning from LOW to HIGH frequency is

0,

 1,
 N-1,

 2,
 N-2

 ...

 [N/2] - 1,
 N - ([N/2] - 1) = [N/2]+1,

 [N/2]

There are [N/2]+1 groups of frequency from index i = 0 to [N/2], each having the frequency = i * SamplingFrequency / N

So the frequency at bin FFT[k] is:

if k <= [N/2] then k * SamplingFrequency / N
if k >= [N/2] then (N-k) * SamplingFrequency / N

How to automatically start a service when running a docker container?

In your Dockerfile, add at the last line

ENTRYPOINT service ssh restart && bash

It works for me

And this is the result:

root@ubuntu:/home/vagrant/docker/add# docker run -i -t ubuntu
 * Restarting OpenBSD Secure Shell server sshd   [ OK ]                                                                      
root@dccc354e422e:~# service ssh status
 * sshd is running

Capturing image from webcam in java?

Java usually doesn't like accessing hardware, so you will need a driver program of some sort, as goldenmean said. I've done this on my laptop by finding a command line program that snaps a picture. Then it's the same as goldenmean explained; you run the command line program from your java program in the takepicture() routine, and the rest of your code runs the same.

Except for the part about reading pixel values into an array, you might be better served by saving the file to BMP, which is nearly that format already, then using the standard java image libraries on it.

Using a command line program adds a dependency to your program and makes it less portable, but so was the webcam, right?

Connect to Oracle DB using sqlplus

As David Aldridge explained, your parentheses should start right after the sqlplus command, so it should be:

sqlplus 'test/test@(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=hostname.com )(PORT=1521)))(CONNECT_DATA=(SID=mysid))'

Default passwords of Oracle 11g?

Once installed in windows Followed the instructions starting from Run SQL Command Line (command prompt)

then... v. SQL> connect /as sysdba

Connected. [SQL prompt response]

vi. SQL> alter user SYS identified by "newpassword";

User altered. [SQL prompt response]

Thank you. This minimized a headache

What is special about /dev/tty?

The 'c' means it's a character device. tty is a special file representing the 'controlling terminal' for the current process.

Character Devices

Unix supports 'device files', which aren't really files at all, but file-like access points to hardware devices. A 'character' device is one which is interfaced byte-by-byte (as opposed to buffered IO).

TTY

/dev/tty is a special file, representing the terminal for the current process. So, when you echo 1 > /dev/tty, your message ('1') will appear on your screen. Likewise, when you cat /dev/tty, your subsequent input gets duplicated (until you press Ctrl-C).

/dev/tty doesn't 'contain' anything as such, but you can read from it and write to it (for what it's worth). I can't think of a good use for it, but there are similar files which are very useful for simple IO operations (e.g. /dev/ttyS0 is normally your serial port)

This quote is from http://tldp.org/HOWTO/Text-Terminal-HOWTO-7.html#ss7.3 :

/dev/tty stands for the controlling terminal (if any) for the current process. To find out which tty's are attached to which processes use the "ps -a" command at the shell prompt (command line). Look at the "tty" column. For the shell process you're in, /dev/tty is the terminal you are now using. Type "tty" at the shell prompt to see what it is (see manual pg. tty(1)). /dev/tty is something like a link to the actually terminal device name with some additional features for C-programmers: see the manual page tty(4).

Here is the man page: http://linux.die.net/man/4/tty

Attaching click to anchor tag in angular

You can use routerLink (which is an alternative of href for angular 2+) with click event as below to prevent from page reloading

<a [routerLink]="" (click)="onGoToPage2()">Go to page</a>

Count number of files within a directory in Linux?

this is one:

ls -l . | egrep -c '^-'

Note:

ls -1 | wc -l

Which means: ls: list files in dir

-1: (that's a ONE) only one entry per line. Change it to -1a if you want hidden files too

|: pipe output onto...

wc: "wordcount"

-l: count lines.

Trigger insert old values- values that was updated

    createTRIGGER [dbo].[Table] ON [dbo].[table] 
FOR UPDATE
AS
    declare @empid int;
    declare @empname varchar(100);
    declare @empsal decimal(10,2);
    declare @audit_action varchar(100);
    declare @old_v varchar(100)

    select @empid=i.Col_Name1 from inserted i;  
    select @empname=i.Col_Name2  from inserted i;   
    select @empsal=i.Col_Name2 from inserted i;
    select @old_v=d.Col_Name from deleted d

    if update(Col_Name1)
        set @audit_action='Updated Record -- After Update Trigger.';
    if update(Col_Name2)
        set @audit_action='Updated Record -- After Update Trigger.';

    insert into Employee_Test_Audit1(Col_name1,Col_name2,Col_name3,Col_name4,Col_name5,Col_name6(Old_values)) 
    values(@empid,@empname,@empsal,@audit_action,getdate(),@old_v);

    PRINT '----AFTER UPDATE Trigger fired-----.'

SSIS package creating Hresult: 0x80004005 Description: "Login timeout expired" error

I finally found the problem. The error was not the good one.

Apparently, Ole DB source have a bug that might make it crash and throw that error. I replaced the OLE DB destination with a OLE DB Command with the insert statement in it and it fixed it.

The link the got me there: http://social.msdn.microsoft.com/Forums/en-US/sqlintegrationservices/thread/fab0e3bf-4adf-4f17-b9f6-7b7f9db6523c/

Strange Bug, Hope it will help other people.

Printing with "\t" (tabs) does not result in aligned columns

Building on this question, I use the following code to indent my messages:

String prefix1 = "short text:";
String prefix2 = "looooooooooooooong text:";
String msg = "indented";
/*
* The second string begins after 40 characters. The dash means that the
* first string is left-justified.
*/
String format = "%-40s%s%n";
System.out.printf(format, prefix1, msg);
System.out.printf(format, prefix2, msg);

This is the output:

short text:                             indented
looooooooooooooong text:                indented

This is documented in section "Flag characters" in man 3 printf.

How do I write a bash script to restart a process if it dies?

if ! test -f $PIDFILE || ! psgrep `cat $PIDFILE`; then
    restart_process
    # Write PIDFILE
    echo $! >$PIDFILE
fi

Why Would I Ever Need to Use C# Nested Classes

what I don't get is why I would ever need to do this

I think you never need to do this. Given a nested class like this ...

class A
{
  //B is used to help implement A
  class B
  {
    ...etc...
  }
  ...etc...
}

... you can always move the inner/nested class to global scope, like this ...

class A
{
  ...etc...
}

//B is used to help implement A
class B
{
  ...etc...
}

However, when B is only used to help implement A, then making B an inner/nested class has two advantages:

  • It doesn't pollute the global scope (e.g. client code which can see A doesn't know that the B class even exists)
  • The methods of B implicitly have access to private members of A; whereas if B weren't nested inside A, B wouldn't be able to access members of A unless those members were internal or public; but then making those members internal or public would expose them to other classes too (not just B); so instead, keep those methods of A private and let B access them by declaring B as a nested class. If you know C++, this is like saying that in C# all nested classes are automatically a 'friend' of the class in which they're contained (and, that declaring a class as nested is the only way to declare friendship in C#, since C# doesn't have a friend keyword).

When I say that B can access private members of A, that's assuming that B has a reference to A; which it often does, since nested classes are often declared like this ...

class A
{
  //used to help implement A
  class B
  {
    A m_a;
    internal B(A a) { m_a = a; }
    ...methods of B can access private members of the m_a instance...
  }
  ...etc...
}

... and constructed from a method of A using code like this ...

//create an instance of B, whose implementation can access members of self
B b = new B(this);

You can see an example in Mehrdad's reply.

Setting mime type for excel document

You should always use below MIME type if you want to serve excel file in xlsx format

application/vnd.openxmlformats-officedocument.spreadsheetml.sheet 

How do I rename the extension for a bunch of files?

For Ubuntu Users :

rename 's/\.html$/\.txt/' *.html

How do you explicitly set a new property on `window` in TypeScript?

Most of the other answers are not perfect.

  • Some of them just suppress the type inference for show.
  • Some of the others only care about global variables as namespaces, but not as interfaces/classes

I also encounter the similar problem this morning. I tried so many "solutions" on StackOverflow, but none of them produced absolutely no type errors and enabled triggering type jumping in IDE(webstorm or vscode).

Finally, from here

https://github.com/Microsoft/TypeScript/issues/3180#issuecomment-102523512

I found a reasonable solution to attach typings for a global variable that acts as interface/class and namespace both.

Example is below:

// typings.d.ts
declare interface Window {
    myNamespace?: MyNamespace & typeof MyNamespace
}

declare interface MyNamespace {
    somemethod?()
}

declare namespace MyNamespace {
    // ...
}

The code above merges the typings of namespace MyNamespace and interface MyNamespace into the global variable myNamespace(the property of window).

Object of custom type as dictionary key

You need to add 2 methods, note __hash__ and __eq__:

class MyThing:
    def __init__(self,name,location,length):
        self.name = name
        self.location = location
        self.length = length

    def __hash__(self):
        return hash((self.name, self.location))

    def __eq__(self, other):
        return (self.name, self.location) == (other.name, other.location)

    def __ne__(self, other):
        # Not strictly necessary, but to avoid having both x==y and x!=y
        # True at the same time
        return not(self == other)

The Python dict documentation defines these requirements on key objects, i.e. they must be hashable.

MySQL WHERE IN ()

Your query translates to

SELECT * FROM table WHERE id='1' or id='2' or id='3' or id='4';

It will only return the results that match it.


One way of solving it avoiding the complexity would be, chaning the datatype to SET. Then you could use, FIND_IN_SET

SELECT * FROM table WHERE FIND_IN_SET('1', id);

How to automatically generate getters and setters in Android Studio

You can use AndroidAccessors Plugin of Android Studio to generate getter and setter without m as prefix to methods

Ex: mId; Will generate getId() and setId() instead of getmId() and setmId()

plugin screenshot

CSS/Javascript to force html table row on a single line

If you don't want the text to wrap and you don't want the size of the column to get bigger then set a width and height on the column and set "overflow: hidden" in your stylesheet.

To do this on only one column you will want to add a class to that column on each row. Otherwise you can set it on all columns, that is up to you.

Html:

<table width="300px">
<tr>
    <td>Column 1</td><td>Column 2</td>
</tr>
<tr>
   <td class="column-1">this is the text in column one which wraps</td>
   <td>this is the column two test</td>
</tr>
</table>

stylsheet:

.column-1
{
  overflow: hidden;
  width: 150px;
  height: 1.2ex; 
}

An ex unit is the relative font size for height, if you are using pixels to set the font size you may wish to use that instead.

How to get the difference between two arrays of objects in JavaScript

JavaScript has Maps, that provide O(1) insertion and lookup time. Therefore this can be solved in O(n) (and not O(n²) as all the other answers do). For that, it is necessary to generate a unique primitive (string / number) key for each object. One could JSON.stringify, but that's quite error prone as the order of elements could influence equality:

 JSON.stringify({ a: 1, b: 2 }) !== JSON.stringify({ b: 2, a: 1 })

Therefore, I'd take a delimiter that does not appear in any of the values and compose a string manually:

const toHash = value => value.value + "@" + value.display;

Then a Map gets created. When an element exists already in the Map, it gets removed, otherwise it gets added. Therefore only the elements that are included odd times (meaning only once) remain. This will only work if the elements are unique in each array:

const entries = new Map();

for(const el of [...firstArray, ...secondArray]) {
  const key = toHash(el);
  if(entries.has(key)) {
    entries.delete(key);
  } else {
    entries.set(key, el);
  }
}

const result = [...entries.values()];

_x000D_
_x000D_
const firstArray = [_x000D_
    { value: "0", display: "Jamsheer" },_x000D_
    { value: "1", display: "Muhammed" },_x000D_
    { value: "2", display: "Ravi" },_x000D_
    { value: "3", display: "Ajmal" },_x000D_
    { value: "4", display: "Ryan" }_x000D_
]_x000D_
_x000D_
const secondArray = [_x000D_
    { value: "0", display: "Jamsheer" },_x000D_
    { value: "1", display: "Muhammed" },_x000D_
    { value: "2", display: "Ravi" },_x000D_
    { value: "3", display: "Ajmal" },_x000D_
];_x000D_
_x000D_
const toHash = value => value.value + "@" + value.display;_x000D_
_x000D_
const entries = new Map();_x000D_
_x000D_
for(const el of [...firstArray, ...secondArray]) {_x000D_
  const key = toHash(el);_x000D_
  if(entries.has(key)) {_x000D_
    entries.delete(key);_x000D_
  } else {_x000D_
    entries.set(key, el);_x000D_
  }_x000D_
}_x000D_
  _x000D_
const result = [...entries.values()];_x000D_
_x000D_
console.log(result);
_x000D_
_x000D_
_x000D_

Length of string in bash

Using your example provided

#KISS (Keep it simple stupid)
size=${#myvar}
echo $size

How to embed a .mov file in HTML?

Well, if you don't want to do the work yourself (object elements aren't really all that hard), you could always use Mike Alsup's Media plugin: http://jquery.malsup.com/media/

CodeIgniter: 404 Page Not Found on Live Server

Please check the root/application/core/ folder files whether if you have used any of MY_Loader.php, MY_Parser.php or MY_Router.php files.

If so, please try by removing above files from the folder and check whether that make any difference. In fact, just clean that folder by just keeping the default index.html file.

I have found these files caused the issue to route to the correct Controller's functions.

Hope that helps!

How to Get Element By Class in JavaScript?

I assume this was not a valid option when this was originally asked, but you can now use document.getElementsByClassName('');. For example:

var elements = document.getElementsByClassName(names); // or:
var elements = rootElement.getElementsByClassName(names);

See the MDN documentation for more.

pandas groupby sort within groups

You could also just do it in one go, by doing the sort first and using head to take the first 3 of each group.

In[34]: df.sort_values(['job','count'],ascending=False).groupby('job').head(3)

Out[35]: 
   count     job source
4      7   sales      E
2      6   sales      C
1      4   sales      B
5      5  market      A
8      4  market      D
6      3  market      B

How to create a Java cron job

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

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

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

Convert string to int if string is a number

Here are a three functions that might be useful. First checks the string for a proper numeric format, second and third function converts a string to Long or Double.

Function IsValidNumericEntry(MyString As String) As Boolean
'********************************************************************************
'This function checks the string entry to make sure that valid digits are in the string.
'It checks to make sure the + and - are the first character if entered and no duplicates.
'Valid charcters are 0 - 9, + - and the .
'********************************************************************************
Dim ValidEntry As Boolean
Dim CharCode As Integer
Dim ValidDigit As Boolean
Dim ValidPlus As Boolean
Dim ValidMinus As Boolean
Dim ValidDecimal As Boolean
Dim ErrMsg As String

ValidDigit = False
ValidPlus = False
ValidMinus = False
ValidDecimal = False

ValidEntry = True
For x = 1 To Len(MyString)
    CharCode = Asc(Mid(MyString, x, 1))
    Select Case CharCode

    Case 48 To 57 ' Digits 0 - 9
        ValidDigit = True

    Case 43 ' Plus sign

    If ValidPlus Then 'One has already been detected and this is a duplicate
        ErrMsg = "Invalid entry....too many plus signs!"
        ValidEntry = False
        Exit For
    ElseIf x = 1 Then 'if in the first positon it is valide
        ValidPlus = True
    Else 'Not in first position and it is invalid
        ErrMsg = "Invalide entry....Plus sign not in the correct position! "
        ValidEntry = False
        Exit For
    End If

    Case 45 ' Minus sign

    If ValidMinus Then 'One has already been detected and this is a duplicate
        ErrMsg = "Invalide entry....too many minus signs! "
        ValidEntry = False
        Exit For
    ElseIf x = 1 Then 'if in the first position it is valid
        ValidMinus = True
    Else 'Not in first position and it is invalid
        ErrMsg = "Invalide entry....Minus sign not in the correct position! "
        ValidEntry = False
        Exit For
    End If

    Case 46 ' Period

    If ValidDecimal Then 'One has already been detected and this is a duplicate
        ErrMsg = "Invalide entry....too many decimals!"
        ValidEntry = False
        Exit For
    Else
        ValidDecimal = True
    End If

    Case Else
        ErrMsg = "Invalid numerical entry....Only digits 0-9 and the . + - characters are valid!"
        ValidEntry = False
        Exit For

    End Select

Next

    If ValidEntry And ValidDigit Then
        IsValidNumericEntry = True
    Else
        If ValidDigit = False Then
            ErrMsg = "Text string contains an invalid numeric format." & vbCrLf _
            & "Use only one of the following formats!" & vbCrLf _
            & "(+dd.dd  -dd.dd  +dd  -dd  dd.d or dd)! "
        End If
        MsgBox (ErrMsg & vbCrLf & vbCrLf & "You Entered:   " & MyString)
        IsValidNumericEntry = False
    End If

End Function

Function ConvertToLong(stringVal As String) As Long
'Assumes the user has verified the string contains a valide numeric entry.
'User should call the function IsValidNumericEntry first especially after any user input
'to verify that the user has entered a proper number.

 ConvertToLong = CLng(stringVal)


End Function
Function ConvertToDouble(stringVal As String) As Double
'Assumes the user has verified the string contains a valide numeric entry.
'User should call the function IsValidNumericEntry first especially after any user input
'to verify that the user has entered a proper number.

    ConvertToDouble = CDbl(stringVal)

End Function

Can you append strings to variables in PHP?

PHP syntax is little different in case of concatenation from JavaScript. Instead of (+) plus a (.) period is used for string concatenation.

<?php

$selectBox = '<select name="number">';
for ($i=1;$i<=100;$i++)
{
    $selectBox += '<option value="' . $i . '">' . $i . '</option>'; // <-- (Wrong) Replace + with .
    $selectBox .= '<option value="' . $i . '">' . $i . '</option>'; // <-- (Correct) Here + is replaced .
}
$selectBox += '</select>'; // <-- (Wrong) Replace + with .
$selectBox .= '</select>'; // <-- (Correct) Here + is replaced .
echo $selectBox;

?>

Initialising an array of fixed size in python

An easy solution is x = [None]*length, but note that it initializes all list elements to None. If the size is really fixed, you can do x=[None,None,None,None,None] as well. But strictly speaking, you won't get undefined elements either way because this plague doesn't exist in Python.

JavaScript to get rows count of a HTML table

This is another option, using jQuery and getting only tbody rows (with the data) and desconsidering thead/tfoot.

$("#tableId > tbody > tr").length

_x000D_
_x000D_
console.log($("#myTableId > tbody > tr").length);
_x000D_
.demo {
   width:100%;
   height:100%;
   border:1px solid #C0C0C0;
   border-collapse:collapse;
   border-spacing:2px;
   padding:5px;
}

.demo caption {
   caption-side:top;
   text-align:center;
}

.demo th {
   border:1px solid #C0C0C0;
   padding:5px;
   background:#F0F0F0;
}

.demo td {
   border:1px solid #C0C0C0;
   text-align:left;
   padding:5px;
   background:#FFFFFF;
}
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<table id="myTableId" class="demo">
   <caption>Table 1</caption>
   <thead>
      <tr>
         <th>Header 1</th>
         <th>Header 2</th>
         <th>Header 3</th>
         <th>Header 4</th>
      </tr>
   </thead>
   <tbody>
      <tr>
         <td>&nbsp;</td>
         <td>&nbsp;</td>
         <td>&nbsp;</td>
         <td>&nbsp;</td>
      </tr>
      <tr>
         <td>&nbsp;</td>
         <td>&nbsp;</td>
         <td>&nbsp;</td>
         <td>&nbsp;</td>
      </tr>
      <tr>
         <td>&nbsp;</td>
         <td>&nbsp;</td>
         <td>&nbsp;</td>
         <td>&nbsp;</td>
      </tr>
      <tr>
         <td>&nbsp;</td>
         <td>&nbsp;</td>
         <td>&nbsp;</td>
         <td>&nbsp;</td>
      </tr>
   </tbody>
   <tfoot>
      <tr>
         <td colspan=4 style="background:#F0F0F0">&nbsp; </td>
      </tr>
   </tfoot>
</table>
_x000D_
_x000D_
_x000D_

Does a finally block always get executed in Java?

finally will execute and that is for sure.

finally will not execute in below cases:

case 1 :

When you are executing System.exit().

case 2 :

When your JVM / Thread crashes.

case 3 :

When your execution is stopped in between manually.

Select folder dialog WPF

I wrote about it on my blog a long time ago, WPF's support for common file dialogs is really bad (or at least is was in 3.5 I didn't check in version 4) - but it's easy to work around it.

You need to add the correct manifest to your application - that will give you a modern style message boxes and folder browser (WinForms FolderBrowserDialog) but not WPF file open/save dialogs, this is described in those 3 posts (if you don't care about the explanation and only want the solution go directly to the 3rd):

Fortunately, the open/save dialogs are very thin wrappers around the Win32 API that is easy to call with the right flags to get the Vista/7 style (after setting the manifest)

Insert data to MySql DB and display if insertion is success or failure

According to the book PHP and MySQL for Dynamic Web Sites (4th edition)

Example:

$r = mysqli_query($dbc, $q);

For simple queries like INSERT, UPDATE, DELETE, etc. (which do not return records), the $r variable—short for result—will be either TRUE or FALSE, depending upon whether the query executed successfully.

Keep in mind that “executed successfully” means that it ran without error; it doesn’t mean that the query’s execution necessarily had the desired result; you’ll need to test for that.

Then how to test?

While the mysqli_num_rows() function will return the number of rows generated by a SELECT query, mysqli_affected_rows() returns the number of rows affected by an INSERT, UPDATE, or DELETE query. It’s used like so:

$num = mysqli_affected_rows($dbc);

Unlike mysqli_num_rows(), the one argument the function takes is the database connection ($dbc), not the results of the previous query ($r).

Couldn't process file resx due to its being in the Internet or Restricted zone or having the mark of the web on the file

I stumbled upon another possible reason of this error. If you use NTFS symbolic links in your project tree, and probably subst'ed drives, you may get this error even if they point to your local drive. If this is the case, try to avoid the situation when .resx files are reached via symlinks.

Reading from text file until EOF repeats last line

At the end of the last line, you have a new line character, which is not read by >> operator and it is not an end of file. Please, make an experiment and delete the new line (thelast character in file) - you will not get the duplication. To have a flexible code and avoid unwanted effects just apply any solution given by other users.

Scikit-learn train_test_split with indices

The docs mention train_test_split is just a convenience function on top of shuffle split.

I just rearranged some of their code to make my own example. Note the actual solution is the middle block of code. The rest is imports, and setup for a runnable example.

from sklearn.model_selection import ShuffleSplit
from sklearn.utils import safe_indexing, indexable
from itertools import chain
import numpy as np
X = np.reshape(np.random.randn(20),(10,2)) # 10 training examples
y = np.random.randint(2, size=10) # 10 labels
seed = 1

cv = ShuffleSplit(random_state=seed, test_size=0.25)
arrays = indexable(X, y)
train, test = next(cv.split(X=X))
iterator = list(chain.from_iterable((
    safe_indexing(a, train),
    safe_indexing(a, test),
    train,
    test
    ) for a in arrays)
)
X_train, X_test, train_is, test_is, y_train, y_test, _, _  = iterator

print(X)
print(train_is)
print(X_train)

Now I have the actual indexes: train_is, test_is

Which are more performant, CTE or temporary tables?

So the query I was assigned to optimize was written with two CTEs in SQL server. It was taking 28sec.

I spent two minutes converting them to temp tables and the query took 3 seconds

I added an index to the temp table on the field it was being joined on and got it down to 2 seconds

Three minutes of work and now its running 12x faster all by removing CTE. I personally will not use CTEs ever they are tougher to debug as well.

The crazy thing is the CTEs were both only used once and still putting an index on them proved to be 50% faster.

Python convert object to float

  • You can use pandas.Series.astype
  • You can do something like this :

    weather["Temp"] = weather.Temp.astype(float)
    
  • You can also use pd.to_numeric that will convert the column from object to float

  • For details on how to use it checkout this link :http://pandas.pydata.org/pandas-docs/version/0.20/generated/pandas.to_numeric.html
  • Example :

    s = pd.Series(['apple', '1.0', '2', -3])
    print(pd.to_numeric(s, errors='ignore'))
    print("=========================")
    print(pd.to_numeric(s, errors='coerce'))
    
  • Output:

    0    apple
    1      1.0
    2        2
    3       -3
    =========================
    dtype: object
    0    NaN
    1    1.0
    2    2.0
    3   -3.0
    dtype: float64
    
  • In your case you can do something like this:

    weather["Temp"] = pd.to_numeric(weather.Temp, errors='coerce')
    
  • Other option is to use convert_objects
  • Example is as follows

    >> pd.Series([1,2,3,4,'.']).convert_objects(convert_numeric=True)
    
    0     1
    1     2
    2     3
    3     4
    4   NaN
    dtype: float64
    
  • You can use this as follows:

    weather["Temp"] = weather.Temp.convert_objects(convert_numeric=True)
    
  • I have showed you examples because if any of your column won't have a number then it will be converted to NaN... so be careful while using it.

Non greedy (reluctant) regex matching in sed?

Neither basic nor extended Posix/GNU regex recognizes the non-greedy quantifier; you need a later regex. Fortunately, Perl regex for this context is pretty easy to get:

perl -pe 's|(http://.*?/).*|\1|'

What is the meaning of single and double underscore before an object name?

Since so many people are referring to Raymond's talk, I'll just make it a little easier by writing down what he said:

The intention of the double underscores was not about privacy. The intention was to use it exactly like this

class Circle(object):

    def __init__(self, radius):
        self.radius = radius

    def area(self):
        p = self.__perimeter()
        r = p / math.pi / 2.0
        return math.pi * r ** 2.0

    def perimeter(self):
        return 2.0 * math.pi * self.radius

    __perimeter = perimeter  # local reference


class Tire(Circle):

    def perimeter(self):
        return Circle.perimeter(self) * 1.25

It's actually the opposite of privacy, it's all about freedom. It makes your subclasses free to override any one method without breaking the others.

Say you don't keep a local reference of perimeter in Circle. Now, a derived class Tire overrides the implementation of perimeter, without touching area. When you call Tire(5).area(), in theory it should still be using Circle.perimeter for computation, but in reality it's using Tire.perimeter, which is not the intended behavior. That's why we need a local reference in Circle.

But why __perimeter instead of _perimeter? Because _perimeter still gives derived class the chance to override:

class Tire(Circle):

    def perimeter(self):
        return Circle.perimeter(self) * 1.25

    _perimeter = perimeter

Double underscores has name mangling, so there's a very little chance that the local reference in parent class get override in derived class. thus "makes your subclasses free to override any one method without breaking the others".

If your class won't be inherited, or method overriding does not break anything, then you simply don't need __double_leading_underscore.

SQLite Query in Android to count rows

Assuming you already have a Database (db) connection established, I think the most elegant way is to stick to the Cursor class, and do something like:

String selection = "uname = ? AND pwd = ?";
String[] selectionArgs = {loginname, loginpass};
String tableName = "YourTable";
Cursor c = db.query(tableName, null, selection, selectionArgs, null, null, null);
int result = c.getCount();
c.close();
return result;

How to capture Enter key press?

Small bit of generic jQuery for you..

$('div.search-box input[type=text]').on('keydown', function (e) {
    if (e.which == 13) {
        $(this).parent().find('input[type=submit]').trigger('click');
        return false;
     }
});

This works on the assumes that the textbox and submit button are wrapped on the same div. works a treat with multiple search boxes on a page

Float sum with javascript

(parseFloat('2.3') + parseFloat('2.4')).toFixed(1);

its going to give you solution i suppose

Make element fixed on scroll

You can do this with css too.

just use position:fixed; for what you want to be fixed when you scroll down.

you can have some examples here:

http://davidwalsh.name/demo/css-fixed-position.php

http://demo.tutorialzine.com/2010/06/microtut-how-css-position-works/demo.html

How to replace existing value of ArrayList element in Java

Use the set method to replace the old value with a new one.

list.set( 2, "New" );

How can I get the SQL of a PreparedStatement?

I've extracted my sql from PreparedStatement using preparedStatement.toString() In my case toString() returns String like this:

org.hsqldb.jdbc.JDBCPreparedStatement@7098b907[sql=[INSERT INTO 
TABLE_NAME(COLUMN_NAME, COLUMN_NAME, COLUMN_NAME) VALUES(?, ?, ?)],
parameters=[[value], [value], [value]]]

Now I've created a method (Java 8), which is using regex to extract both query and values and put them into map:

private Map<String, String> extractSql(PreparedStatement preparedStatement) {
    Map<String, String> extractedParameters = new HashMap<>();
    Pattern pattern = Pattern.compile(".*\\[sql=\\[(.*)],\\sparameters=\\[(.*)]].*");
    Matcher matcher = pattern.matcher(preparedStatement.toString());
    while (matcher.find()) {
      extractedParameters.put("query", matcher.group(1));
      extractedParameters.put("values", Stream.of(matcher.group(2).split(","))
          .map(line -> line.replaceAll("(\\[|])", ""))
          .collect(Collectors.joining(", ")));
    }
    return extractedParameters;
  }

This method returns map where we have key-value pairs:

"query" -> "INSERT INTO TABLE_NAME(COLUMN_NAME, COLUMN_NAME, COLUMN_NAME) VALUES(?, ?, ?)"
"values" -> "value,  value,  value"

Now - if you want values as list you can just simply use:

List<String> values = Stream.of(yourExtractedParametersMap.get("values").split(","))
    .collect(Collectors.toList());

If your preparedStatement.toString() is different than in my case it's just a matter of "adjusting" regex.

Symfony - generate url with parameter in controller

make sure your controller extends Symfony\Bundle\FrameworkBundle\Controller\Controller;

you should also check app/console debug:router in terminal to see what name symfony has named the route

in my case it used a minus instead of an underscore

i.e blog-show

$uri = $this->generateUrl('blog-show', ['slug' => 'my-blog-post']);

Oracle Date datatype, transformed to 'YYYY-MM-DD HH24:MI:SS TMZ' through SQL

There's a bit of confusion in your question:

  • a Date datatype doesn't save the time zone component. This piece of information is truncated and lost forever when you insert a TIMESTAMP WITH TIME ZONE into a Date.
  • When you want to display a date, either on screen or to send it to another system via a character API (XML, file...), you use the TO_CHAR function. In Oracle, a Date has no format: it is a point in time.
  • Reciprocally, you would use TO_TIMESTAMP_TZ to convert a VARCHAR2 to a TIMESTAMP, but this won't convert a Date to a TIMESTAMP.
  • You use FROM_TZ to add the time zone information to a TIMESTAMP (or a Date).
  • In Oracle, CST is a time zone but CDT is not. CDT is a daylight saving information.
  • To complicate things further, CST/CDT (-05:00) and CST/CST (-06:00) will have different values obviously, but the time zone CST will inherit the daylight saving information depending upon the date by default.

So your conversion may not be as simple as it looks.

Assuming that you want to convert a Date d that you know is valid at time zone CST/CST to the equivalent at time zone CST/CDT, you would use:

SQL> SELECT from_tz(d, '-06:00') initial_ts,
  2         from_tz(d, '-06:00') at time zone ('-05:00') converted_ts
  3    FROM (SELECT cast(to_date('2012-10-09 01:10:21',
  4                              'yyyy-mm-dd hh24:mi:ss') as timestamp) d
  5            FROM dual);

INITIAL_TS                      CONVERTED_TS
------------------------------- -------------------------------
09/10/12 01:10:21,000000 -06:00 09/10/12 02:10:21,000000 -05:00

My default timestamp format has been used here. I can specify a format explicitely:

SQL> SELECT to_char(from_tz(d, '-06:00'),'yyyy-mm-dd hh24:mi:ss TZR') initial_ts,
  2         to_char(from_tz(d, '-06:00') at time zone ('-05:00'),
  3                 'yyyy-mm-dd hh24:mi:ss TZR') converted_ts
  4    FROM (SELECT cast(to_date('2012-10-09 01:10:21',
  5                              'yyyy-mm-dd hh24:mi:ss') as timestamp) d
  6            FROM dual);

INITIAL_TS                      CONVERTED_TS
------------------------------- -------------------------------
2012-10-09 01:10:21 -06:00      2012-10-09 02:10:21 -05:00

How to create range in Swift?

If anyone want to create NSRange object can create as:

let range: NSRange = NSRange.init(location: 0, length: 5)

this will create range with position 0 and length 5

Using Javascript's atob to decode base64 doesn't properly decode utf-8 strings

Here is 2018 updated solution as described in the Mozilla Development Resources

TO ENCODE FROM UNICODE TO B64

function b64EncodeUnicode(str) {
    // first we use encodeURIComponent to get percent-encoded UTF-8,
    // then we convert the percent encodings into raw bytes which
    // can be fed into btoa.
    return btoa(encodeURIComponent(str).replace(/%([0-9A-F]{2})/g,
        function toSolidBytes(match, p1) {
            return String.fromCharCode('0x' + p1);
    }));
}

b64EncodeUnicode('? à la mode'); // "4pyTIMOgIGxhIG1vZGU="
b64EncodeUnicode('\n'); // "Cg=="

TO DECODE FROM B64 TO UNICODE

function b64DecodeUnicode(str) {
    // Going backwards: from bytestream, to percent-encoding, to original string.
    return decodeURIComponent(atob(str).split('').map(function(c) {
        return '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2);
    }).join(''));
}

b64DecodeUnicode('4pyTIMOgIGxhIG1vZGU='); // "? à la mode"
b64DecodeUnicode('Cg=='); // "\n"

How to efficiently concatenate strings in go

My original suggestion was

s12 := fmt.Sprint(s1,s2)

But above answer using bytes.Buffer - WriteString() is the most efficient way.

My initial suggestion uses reflection and a type switch. See (p *pp) doPrint and (p *pp) printArg
There is no universal Stringer() interface for basic types, as I had naively thought.

At least though, Sprint() internally uses a bytes.Buffer. Thus

`s12 := fmt.Sprint(s1,s2,s3,s4,...,s1000)`

is acceptable in terms of memory allocations.

=> Sprint() concatenation can be used for quick debug output.
=> Otherwise use bytes.Buffer ... WriteString

Entry point for Java applications: main(), init(), or run()?

This is a peculiar question because it's not supposed to be a matter of choice.

When you launch the JVM, you specify a class to run, and it is the main() of this class where your program starts.

By init(), I assume you mean the JApplet method. When an applet is launched in the browser, the init() method of the specified applet is executed as the first order of business.

By run(), I assume you mean the method of Runnable. This is the method invoked when a new thread is started.

  • main: program start
  • init: applet start
  • run: thread start

If Eclipse is running your run() method even though you have no main(), then it is doing something peculiar and non-standard, but not infeasible. Perhaps you should post a sample class that you've been running this way.

How to install Android app on LG smart TV?

LG, VIZIO, SAMSUNG and PANASONIC TVs are not android based, and you cannot run APKs off of them... You should just buy a fire stick and call it a day. The only TVs that are android-based, and you can install APKs are: SONY, PHILIPS and SHARP.
#FACTS.

Git says remote ref does not exist when I delete remote branch

Given that the remote branch is remotes/origin/test you can use two ways:

git push origin --delete test

and

git branch -D -r origin/test

How to set max_connections in MySQL Programmatically

How to change max_connections

You can change max_connections while MySQL is running via SET:

mysql> SET GLOBAL max_connections = 5000;
Query OK, 0 rows affected (0.00 sec)

mysql> SHOW VARIABLES LIKE "max_connections";
+-----------------+-------+
| Variable_name   | Value |
+-----------------+-------+
| max_connections | 5000  |
+-----------------+-------+
1 row in set (0.00 sec)

To OP

timeout related

I had never seen your error message before, so I googled. probably, you are using Connector/Net. Connector/Net Manual says there is max connection pool size. (default is 100) see table 22.21.

I suggest that you increase this value to 100k or disable connection pooling Pooling=false

UPDATED

he has two questions.

Q1 - what happens if I disable pooling Slow down making DB connection. connection pooling is a mechanism that use already made DB connection. cost of Making new connection is high. http://en.wikipedia.org/wiki/Connection_pool

Q2 - Can the value of pooling be increased or the maximum is 100?

you can increase but I'm sure what is MAX value, maybe max_connections in my.cnf

My suggestion is that do not turn off Pooling, increase value by 100 until there is no connection error.

If you have Stress Test tool like JMeter you can test youself.

MySQL Select Date Equal to Today

This query will use index if you have it for signup_date field

SELECT users.id, DATE_FORMAT(users.signup_date, '%Y-%m-%d') 
    FROM users 
    WHERE signup_date >= CURDATE() && signup_date < (CURDATE() + INTERVAL 1 DAY)

How to enable remote access of mysql in centos?

Bind-address XXX.XX.XX.XXX in /etc/my.cnf

comment line:

skip-networking

or

skip-external-locking

after edit hit service mysqld restart

login into mysql and hit this query:

GRANT ALL PRIVILEGES ON dbname.* TO 'username'@'%' IDENTIFIED BY 'password';

FLUSH PRIVILEGES;
quit;

add firewall rule:

iptables -I INPUT -i eth0 -p tcp --destination-port 3306 -j ACCEPT

Remove Duplicates from range of cells in excel vba

If you got only one column in the range to clean, just add "(1)" to the end. It indicates in wich column of the range Excel will remove the duplicates. Something like:

 Sub norepeat()

    Range("C8:C16").RemoveDuplicates (1)

End Sub

Regards

What are the most widely used C++ vector/matrix math/linear algebra libraries, and their cost and benefit tradeoffs?

So I'm a pretty critical person, and figure if I'm going to invest in a library, I'd better know what I'm getting myself into. I figure it's better to go heavy on the criticism and light on the flattery when scrutinizing; what's wrong with it has many more implications for the future than what's right. So I'm going to go overboard here a little bit to provide the kind of answer that would have helped me and I hope will help others who may journey down this path. Keep in mind that this is based on what little reviewing/testing I've done with these libs. Oh and I stole some of the positive description from Reed.

I'll mention up top that I went with GMTL despite it's idiosyncrasies because the Eigen2 unsafeness was too big of a downside. But I've recently learned that the next release of Eigen2 will contain defines that will shut off the alignment code, and make it safe. So I may switch over.

Update: I've switched to Eigen3. Despite it's idiosyncrasies, its scope and elegance are too hard to ignore, and the optimizations which make it unsafe can be turned off with a define.

Eigen2/Eigen3

Benefits: LGPL MPL2, Clean, well designed API, fairly easy to use. Seems to be well maintained with a vibrant community. Low memory overhead. High performance. Made for general linear algebra, but good geometric functionality available as well. All header lib, no linking required.

Idiocyncracies/downsides: (Some/all of these can be avoided by some defines that are available in the current development branch Eigen3)

  • Unsafe performance optimizations result in needing careful following of rules. Failure to follow rules causes crashes.
    • you simply cannot safely pass-by-value
    • use of Eigen types as members requires special allocator customization (or you crash)
    • use with stl container types and possibly other templates required special allocation customization (or you will crash)
    • certain compilers need special care to prevent crashes on function calls (GCC windows)

GMTL

Benefits: LGPL, Fairly Simple API, specifically designed for graphics engines. Includes many primitive types geared towards rendering (such as planes, AABB, quatenrions with multiple interpolation, etc) that aren't in any other packages. Very low memory overhead, quite fast, easy to use. All header based, no linking necessary.

Idiocyncracies/downsides:

  • API is quirky
    • what might be myVec.x() in another lib is only available via myVec[0] (Readability problem)
      • an array or stl::vector of points may cause you to do something like pointsList[0][0] to access the x component of the first point
    • in a naive attempt at optimization, removed cross(vec,vec) and replaced with makeCross(vec,vec,vec) when compiler eliminates unnecessary temps anyway
    • normal math operations don't return normal types unless you shut off some optimization features e.g.: vec1 - vec2 does not return a normal vector so length( vecA - vecB ) fails even though vecC = vecA - vecB works. You must wrap like: length( Vec( vecA - vecB ) )
    • operations on vectors are provided by external functions rather than members. This may require you to use the scope resolution everywhere since common symbol names may collide
    • you have to do
        length( makeCross( vecA, vecB ) )
      or
        gmtl::length( gmtl::makeCross( vecA, vecB ) )
      where otherwise you might try
        vecA.cross( vecB ).length()
  • not well maintained
    • still claimed as "beta"
    • documentation missing basic info like which headers are needed to use normal functionalty
      • Vec.h does not contain operations for Vectors, VecOps.h contains some, others are in Generate.h for example. cross(vec&,vec&,vec&) in VecOps.h, [make]cross(vec&,vec&) in Generate.h
  • immature/unstable API; still changing.
    • For example "cross" has moved from "VecOps.h" to "Generate.h", and then the name was changed to "makeCross". Documentation examples fail because still refer to old versions of functions that no-longer exist.

NT2

Can't tell because they seem to be more interested in the fractal image header of their web page than the content. Looks more like an academic project than a serious software project.

Latest release over 2 years ago.

Apparently no documentation in English though supposedly there is something in French somewhere.

Cant find a trace of a community around the project.

LAPACK & BLAS

Benefits: Old and mature.

Downsides:

  • old as dinosaurs with really crappy APIs

Spring JPA and persistence.xml

I'm confused. You're injecting a PU into the service layer and not the persistence layer? I don't get that.

I inject the persistence layer into the service layer. The service layer contains business logic and demarcates transaction boundaries. It can include more than one DAO in a transaction.

I don't get the magic in your save() method either. How is the data saved?

In production I configure spring like this:

<jee:jndi-lookup id="entityManagerFactory" jndi-name="persistence/ThePUname" />

along with the reference in web.xml

For unit testing I do this:

<bean id="entityManagerFactory"
    class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"
    p:dataSource-ref="dataSource" p:persistence-xml-location="classpath*:META-INF/test-persistence.xml"
    p:persistence-unit-name="RealPUName" p:jpaDialect-ref="jpaDialect"
    p:jpaVendorAdapter-ref="jpaVendorAdapter" p:loadTimeWeaver-ref="weaver">
</bean>

Best way to center a <div> on a page vertically and horizontally?

Please use following CSS properties for center align element horizontally as well as vertically. This is worked fine for me.

div {
  position: absolute;
  left: 0;
  top: 0;
  right: 0;
  bottom: 0px;
  margin: auto;
  width: 100px;
  height: 100px;
}

iOS change navigation bar title font and color

For Objective-C to set Font and Color

- (void)_setup {
    NSDictionary *barButtonTitleAttributes = @{
                                               NSForegroundColorAttributeName : [UIColor whiteColor],
                                               NSFontAttributeName :[UIFont fontWithName:@"Lato-Regular" size:15.0]
                                               };
    [self.navigationBar setTitleTextAttributes:barButtonTitleAttributes];

}

Git - deleted some files locally, how do I get them from a remote repository

Since git is a distributed VCS, your local repository contains all of the information. No downloading is necessary; you just need to extract the content you want from the repo at your fingertips.

If you haven't committed the deletion, just check out the files from your current commit:

git checkout HEAD <path>

If you have committed the deletion, you need to check out the files from a commit that has them. Presumably it would be the previous commit:

git checkout HEAD^ <path>

but if it's n commits ago, use HEAD~n, or simply fire up gitk, find the SHA1 of the appropriate commit, and paste it in.

How to do this using jQuery - document.getElementById("selectlist").value

In some cases of which I can't remember why but $('#selectlist').val() won't always return the correct item value, so I use $('#selectlist option:selected').val() instead.

Django CSRF Cookie Not Set

I had the same error, in my case adding method_decorator helps:

from django.views.decorators.csrf import csrf_protect
from django.utils.decorators import method_decorator

method_decorator(csrf_protect)
def post(self, request):
    ...

Failed to auto-configure a DataSource: 'spring.datasource.url' is not specified

I ran into this problem when I simply mistyped my jdbc url in application.properties. Hope this helps someone: before:

spring.datasource.url=jdbc://localhost:3306/test

after:

spring.datasource.url=jdbc:mysql://localhost:3306/test

DateTimePicker: pick both date and time

Set the Format to Custom and then specify the format:

dateTimePicker1.Format = DateTimePickerFormat.Custom;
dateTimePicker1.CustomFormat = "MM/dd/yyyy hh:mm:ss";  

or however you want to lay it out. You could then type in directly the date/time. If you use MMM, you'll need to use the numeric value for the month for entry, unless you write some code yourself for that (e.g., 5 results in May)

Don't know about the picker for date and time together. Sounds like a custom control to me.

SQL update fields of one table from fields of another one

The question is old but I felt the best answer hadn't been given, yet.

Is there an UPDATE syntax ... without specifying the column names?

General solution with dynamic SQL

You don't need to know any column names except for some unique column(s) to join on (id in the example). Works reliably for any possible corner case I can think of.

This is specific to PostgreSQL. I am building dynamic code based on the the information_schema, in particular the table information_schema.columns, which is defined in the SQL standard and most major RDBMS (except Oracle) have it. But a DO statement with PL/pgSQL code executing dynamic SQL is totally non-standard PostgreSQL syntax.

DO
$do$
BEGIN

EXECUTE (
SELECT
  'UPDATE b
   SET   (' || string_agg(        quote_ident(column_name), ',') || ')
       = (' || string_agg('a.' || quote_ident(column_name), ',') || ')
   FROM   a
   WHERE  b.id = 123
   AND    a.id = b.id'
FROM   information_schema.columns
WHERE  table_name   = 'a'       -- table name, case sensitive
AND    table_schema = 'public'  -- schema name, case sensitive
AND    column_name <> 'id'      -- all columns except id
);

END
$do$;

Assuming a matching column in b for every column in a, but not the other way round. b can have additional columns.

WHERE b.id = 123 is optional, to update a selected row.

SQL Fiddle.

Related answers with more explanation:

Partial solutions with plain SQL

With list of shared columns

You still need to know the list of column names that both tables share. With a syntax shortcut for updating multiple columns - shorter than what other answers suggested so far in any case.

UPDATE b
SET   (  column1,   column2,   column3)
    = (a.column1, a.column2, a.column3)
FROM   a
WHERE  b.id = 123    -- optional, to update only selected row
AND    a.id = b.id;

SQL Fiddle.

This syntax was introduced with Postgres 8.2 in 2006, long before the question was asked. Details in the manual.

Related:

With list of columns in B

If all columns of A are defined NOT NULL (but not necessarily B),
and you know the column names of B (but not necessarily A).

UPDATE b
SET   (column1, column2, column3, column4)
    = (COALESCE(ab.column1, b.column1)
     , COALESCE(ab.column2, b.column2)
     , COALESCE(ab.column3, b.column3)
     , COALESCE(ab.column4, b.column4)
      )
FROM (
   SELECT *
   FROM   a
   NATURAL LEFT JOIN  b -- append missing columns
   WHERE  b.id IS NULL  -- only if anything actually changes
   AND    a.id = 123    -- optional, to update only selected row
   ) ab
WHERE b.id = ab.id;

The NATURAL LEFT JOIN joins a row from b where all columns of the same name hold same values. We don't need an update in this case (nothing changes) and can eliminate those rows early in the process (WHERE b.id IS NULL).
We still need to find a matching row, so b.id = ab.id in the outer query.

db<>fiddle here
Old sqlfiddle.

This is standard SQL except for the FROM clause.
It works no matter which of the columns are actually present in A, but the query cannot distinguish between actual NULL values and missing columns in A, so it is only reliable if all columns in A are defined NOT NULL.

There are multiple possible variations, depending on what you know about both tables.

Response Content type as CSV

Use text/csv as the content type.

Getting the count of unique values in a column in bash

To see a frequency count for column two (for example):

awk -F '\t' '{print $2}' * | sort | uniq -c | sort -nr

fileA.txt

z    z    a
a    b    c
w    d    e

fileB.txt

t    r    e
z    d    a
a    g    c

fileC.txt

z    r    a
v    d    c
a    m    c

Result:

  3 d
  2 r
  1 z
  1 m
  1 g
  1 b

Remove last characters from a string in C#. An elegant way?

You could use LastIndexOf and Substring combined to get all characters to the left of the last index of the comma within the sting.

string var = var.Substring(0, var.LastIndexOf(','));

What are the differences between Deferred, Promise and Future in JavaScript?

These answers, including the selected answer, are good for introducing promises conceptually, but lacking in specifics of what exactly the differences are in the terminology that arises when using libraries implementing them (and there are important differences).

Since it is still an evolving spec, the answer currently comes from attempting to survey both references (like wikipedia) and implementations (like jQuery):

  • Deferred: Never described in popular references, 1 2 3 4 but commonly used by implementations as the arbiter of promise resolution (implementing resolve and reject). 5 6 7

    Sometimes deferreds are also promises (implementing then), 5 6 other times it's seen as more pure to have the Deferred only capable of resolution, and forcing the user to access the promise for using then. 7

  • Promise: The most all-encompasing word for the strategy under discussion.

    A proxy object storing the result of a target function whose synchronicity we would like to abstract, plus exposing a then function accepting another target function and returning a new promise. 2

    Example from CommonJS:

    > asyncComputeTheAnswerToEverything()
        .then(addTwo)
        .then(printResult);
    44
    

     

    Always described in popular references, although never specified as to whose responsibility resolution falls to. 1 2 3 4

    Always present in popular implementations, and never given resolution abilites. 5 6 7

  • Future: a seemingly deprecated term found in some popular references 1 and at least one popular implementation, 8 but seemingly being phased out of discussion in preference for the term 'promise' 3 and not always mentioned in popular introductions to the topic. 9

    However, at least one library uses the term generically for abstracting synchronicity and error handling, while not providing then functionality. 10 It's unclear if avoiding the term 'promise' was intentional, but probably a good choice since promises are built around 'thenables.' 2

References

  1. Wikipedia on Promises & Futures
  2. Promises/A+ spec
  3. DOM Standard on Promises
  4. DOM Standard Promises Spec WIP
  5. DOJO Toolkit Deferreds
  6. jQuery Deferreds
  7. Q
  8. FutureJS
  9. Functional Javascript section on Promises
  10. Futures in AngularJS Integration Testing

Misc potentially confusing things

How do I get the selected element by name and then get the selected value from a dropdown using jQuery?

MrOBrian's answer shows why your current code doesn't work, with the missing trailing ] and quotes, but here's an easier way to make it work:

onchange='mySelectHandler(this)'

And then:

function mySelectHandler(el){
     var mySelect = $(el)
     // get selected value
     alert ("selected " + mySelect.val())
  }

Or better still, remove the inline event handler altogether and bind the event handler with jQuery:

$('select[name="a[b]"]').change(function() {
    var mySelect = $(this);
    alert("selected " mySelect.val());
});

That last would need to be in a document.ready handler or in a script block that appears after the select element. If you want to run the same function for other selects simply change the selector to something that applies to all, e.g., all selects would be $('select'), or all with a particular class would be $('select.someClass').

Convert a string to int using sql query

Starting with SQL Server 2012, you could use TRY_PARSE or TRY_CONVERT.

SELECT TRY_PARSE(MyVarcharCol as int)

SELECT TRY_CONVERT(int, MyVarcharCol)

'module' has no attribute 'urlencode'

import urllib.parse
urllib.parse.urlencode({'spam': 1, 'eggs': 2, 'bacon': 0})

Setting action for back button in navigation controller

At least in Xcode 5, there is a simple and pretty good (not perfect) solution. In IB, drag a Bar Button Item off the Utilities pane and drop it on the left side of the Navigation Bar where the Back button would be. Set the label to "Back." You will have a functioning button that you can tie to your IBAction and close your viewController. I'm doing some work and then triggering an unwind segue and it works perfectly.

What isn't ideal is that this button does not get the < arrow and does not carry forward the previous VCs title, but I think this can be managed. For my purposes, I set the new Back button to be a "Done" button so it's purpose is clear.

You also end up with two Back buttons in the IB navigator, but it is easy enough to label it for clarity.

enter image description here

How do I split a string in Rust?

Use split()

let mut split = "some string 123 ffd".split("123");

This gives an iterator, which you can loop over, or collect() into a vector.

for s in split {
    println!("{}", s)
}
let vec = split.collect::<Vec<&str>>();
// OR
let vec: Vec<&str> = split.collect();

How to add element in Python to the end of list using list.insert?

You'll have to pass the new ordinal position to insert using len in this case:

In [62]:

a=[1,2,3,4]
a.insert(len(a),5)
a
Out[62]:
[1, 2, 3, 4, 5]

iOS 7 - Status bar overlaps the view

If you simply do NOT want any status bar at all, you need to update your plist with this data: To do this, in the plist, add those 2 settings:

<key>UIStatusBarHidden</key>
<true/>
<key>UIViewControllerBasedStatusBarAppearance</key>
<false/>

In iOS 7 you are expected to design your app with an overlaid transparent status bar in mind. See the new iOS 7 Weather app for example.

Generate unique random numbers between 1 and 100

I would do this:

function randomInt(min, max) {
    return Math.round(min + Math.random()*(max-min));
}
var index = {}, numbers = [];
for (var i=0; i<8; ++i) {
    var number;
    do {
        number = randomInt(1, 100);
    } while (index.hasOwnProperty("_"+number));
    index["_"+number] = true;
    numbers.push(number);
}
delete index;

Send file via cURL from form POST in PHP

Here is my solution, i have been reading a lot of post and they was really helpfull, finaly i build a code for small files, with cUrl and Php, that i think its really usefull.

public function postFile()
{


        $file_url = "test.txt";  //here is the file route, in this case is on same directory but you can set URL too like "http://examplewebsite.com/test.txt"
        $eol = "\r\n"; //default line-break for mime type
        $BOUNDARY = md5(time()); //random boundaryid, is a separator for each param on my post curl function
        $BODY=""; //init my curl body
        $BODY.= '--'.$BOUNDARY. $eol; //start param header
        $BODY .= 'Content-Disposition: form-data; name="sometext"' . $eol . $eol; // last Content with 2 $eol, in this case is only 1 content.
        $BODY .= "Some Data" . $eol;//param data in this case is a simple post data and 1 $eol for the end of the data
        $BODY.= '--'.$BOUNDARY. $eol; // start 2nd param,
        $BODY.= 'Content-Disposition: form-data; name="somefile"; filename="test.txt"'. $eol ; //first Content data for post file, remember you only put 1 when you are going to add more Contents, and 2 on the last, to close the Content Instance
        $BODY.= 'Content-Type: application/octet-stream' . $eol; //Same before row
        $BODY.= 'Content-Transfer-Encoding: base64' . $eol . $eol; // we put the last Content and 2 $eol,
        $BODY.= chunk_split(base64_encode(file_get_contents($file_url))) . $eol; // we write the Base64 File Content and the $eol to finish the data,
        $BODY.= '--'.$BOUNDARY .'--' . $eol. $eol; // we close the param and the post width "--" and 2 $eol at the end of our boundary header.



        $ch = curl_init(); //init curl
        curl_setopt($ch, CURLOPT_HTTPHEADER, array(
                         'X_PARAM_TOKEN : 71e2cb8b-42b7-4bf0-b2e8-53fbd2f578f9' //custom header for my api validation you can get it from $_SERVER["HTTP_X_PARAM_TOKEN"] variable
                         ,"Content-Type: multipart/form-data; boundary=".$BOUNDARY) //setting our mime type for make it work on $_FILE variable
                    );
        curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/1.0 (Windows NT 6.1; WOW64; rv:28.0) Gecko/20100101 Firefox/28.0'); //setting our user agent
        curl_setopt($ch, CURLOPT_URL, "api.endpoint.post"); //setting our api post url
        curl_setopt($ch, CURLOPT_COOKIEJAR, $BOUNDARY.'.txt'); //saving cookies just in case we want
        curl_setopt ($ch, CURLOPT_RETURNTRANSFER, 1); // call return content
        curl_setopt ($ch, CURLOPT_FOLLOWLOCATION, 1); navigate the endpoint
        curl_setopt($ch, CURLOPT_POST, true); //set as post
        curl_setopt($ch, CURLOPT_POSTFIELDS, $BODY); // set our $BODY 


        $response = curl_exec($ch); // start curl navigation

     print_r($response); //print response

}

With this we shoud be get on the "api.endpoint.post" the following vars posted You can easly test with this script, and you should be recive this debugs on the function postFile() at the last row

print_r($response); //print response

public function getPostFile()
{

    echo "\n\n_SERVER\n";
    echo "<pre>";
    print_r($_SERVER['HTTP_X_PARAM_TOKEN']);
    echo "/<pre>";
    echo "_POST\n";
    echo "<pre>";
    print_r($_POST['sometext']);
    echo "/<pre>";
    echo "_FILES\n";
    echo "<pre>";
    print_r($_FILEST['somefile']);
    echo "/<pre>";
}

Here you are it should be work good, could be better solutions but this works and is really helpfull to understand how the Boundary and multipart/from-data mime works on php and curl library,

My Best Reggards,

my apologies about my english but isnt my native language.

What is the difference between a port and a socket?

A socket is a data I/O mechanism. A port is a contractual concept of a communication protocol. A socket can exist without a port. A port can exist witout a specific socket (e.g. if several sockets are active on the same port, which may be allowed for some protocols).

A port is used to determine which socket the receiver should route the packet to, with many protocols, but it is not always required and the receiving socket selection can be done by other means - a port is entirely a tool used by the protocol handler in the network subsystem. e.g. if a protocol does not use a port, packets can go to all listening sockets or any socket.

Handling file renames in git

Best thing is to try it for yourself.

mkdir test
cd test
git init
touch aaa.txt
git add .
git commit -a -m "New file"
mv aaa.txt bbb.txt
git add .
git status
git commit --dry-run -a

Now git status and git commit --dry-run -a shows two different results where git status shows bbb.txt as a new file/ aaa.txt is deleted, and the --dry-run commands shows the actual rename.

~/test$ git status

# On branch master
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#   new file:   bbb.txt
#
# Changes not staged for commit:
#   (use "git add/rm <file>..." to update what will be committed)
#   (use "git checkout -- <file>..." to discard changes in working directory)
#
#   deleted:    aaa.txt
#


/test$ git commit --dry-run -a

# On branch master
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#   renamed:    aaa.txt -> bbb.txt
#

Now go ahead and do the check-in.

git commit -a -m "Rename"

Now you can see that the file is in fact renamed, and what's shown in git status is wrong.

Moral of the story: If you're not sure whether your file got renamed, issue a "git commit --dry-run -a". If its showing that the file is renamed, you're good to go.

JavaScript Chart Library

Protochart is all you need

$("#form1").validate is not a function

youll need to use the latest http://ajax.microsoft.com/ajax/jquery.validate/1.5.5/jquery.validate.js in conjunction with one of the Microsoft's CDN for getting your validation file.

Render HTML to PDF in Django site

https://github.com/nigma/django-easy-pdf

Template:

{% extends "easy_pdf/base.html" %}

{% block content %}
    <div id="content">
        <h1>Hi there!</h1>
    </div>
{% endblock %}

View:

from easy_pdf.views import PDFTemplateView

class HelloPDFView(PDFTemplateView):
    template_name = "hello.html"

If you want to use django-easy-pdf on Python 3 check the solution suggested here.

What's the maximum value for an int in PHP?

(a little bit late, but could be useful)

Only trust PHP_INT_MAX and PHP_INT_SIZE, this value vary on your arch (32/64 bits) and your OS...

Any other "guess" or "hint" can be false.

Visual Studio Code always asking for git credentials

apart from adding the ssh config entries above

if windows

Set-Service ssh-agent -StartupType Automatic 

in powershell now the vs code should not prompt...

Case insensitive 'Contains(string)'

if you want to check if your passed string is in string then there is a simple method for that.

string yourStringForCheck= "abc";
string stringInWhichWeCheck= "Test abc abc";

bool isContained = stringInWhichWeCheck.ToLower().IndexOf(yourStringForCheck.ToLower()) > -1;

This boolean value will return if the string is contained or not

Convert System.Drawing.Color to RGB and Hex Value

For hexadecimal code try this

  1. Get ARGB (Alpha, Red, Green, Blue) representation for the color
  2. Filter out Alpha channel: & 0x00FFFFFF
  3. Format out the value (as hexadecimal "X6" for hex)

For RGB one

  1. Just format out Red, Green, Blue values

Implementation

private static string HexConverter(Color c) {
  return String.Format("#{0:X6}", c.ToArgb() & 0x00FFFFFF);
}

public static string RgbConverter(Color c) {
  return String.Format("RGB({0},{1},{2})", c.R, c.G, c.B);
}

Failed to load resource under Chrome

Check the network tab to see if Chrome failed to download any resource file.

Best way to Format a Double value to 2 Decimal places

No, there is no better way.

Actually you have an error in your pattern. What you want is:

DecimalFormat df = new DecimalFormat("#.00"); 

Note the "00", meaning exactly two decimal places.

If you use "#.##" (# means "optional" digit), it will drop trailing zeroes - ie new DecimalFormat("#.##").format(3.0d); prints just "3", not "3.00".

jQuery - Fancybox: But I don't want scrollbars!

I have face the same problem and after times of trial and error, I found out that you can avoid scrollbars by overriding frame css class.

You can do like this:

iframe.fancybox-iframe {
    overflow:hidden;
}

JS configuration:

jQuery(document).ready(function(){
    $("a.various").fancybox({
        'width'             : 'auto',
        'height'            : 'auto',
        'autoScale'         : false,
        'autoDimensions'    : false,
        'scrolling'         : 'no',
        'transitionIn'      : 'none',
        'transitionOut'     : 'none',
        'type'              : 'iframe'  
    }); 
});

Note: Your fancybox box type must be an iframe for this to take effect.

Is there a "goto" statement in bash?

There is one more ability to achieve a desired results: command trap. It can be used to clean-up purposes for example.

How do you remove a Cookie in a Java Servlet

In my environment, following code works. Although looks redundant at first glance, cookies[i].setValue(""); and cookies[i].setPath("/"); are necessary to clear the cookie properly.

private void eraseCookie(HttpServletRequest req, HttpServletResponse resp) {
    Cookie[] cookies = req.getCookies();
    if (cookies != null)
        for (Cookie cookie : cookies) {
            cookie.setValue("");
            cookie.setPath("/");
            cookie.setMaxAge(0);
            resp.addCookie(cookie);
        }
}

How to right align widget in horizontal linear layout Android?

Here is a sample. the key to arrange is as follows

android:layout_width="0dp"
android:layout_weight="1"

Complete code

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal"
    android:padding="5dp">

    <TextView
        android:id="@+id/categoryName"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="abcd" />

    <TextView
        android:id="@+id/spareName"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:text="efgh" />

</LinearLayout>

enter image description here

Copy Files from Windows to the Ubuntu Subsystem

You should only access Linux files system (those located in lxss folder) from inside WSL; DO NOT create/modify any files in lxss folder in Windows - it's dangerous and WSL will not see these files.

Files can be shared between WSL and Windows, though; put the file outside of lxss folder. You can access them via drvFS (/mnt) such as /mnt/c/Users/yourusername/files within WSL. These files stay synced between WSL and Windows.

For details and why, see: https://blogs.msdn.microsoft.com/commandline/2016/11/17/do-not-change-linux-files-using-windows-apps-and-tools/

Get textarea text with javascript or Jquery

Get textarea text with JavaScript:

<!DOCTYPE html>
<body>
<form id="form1">
    <div>
        <textarea id="area1" rows="5">Yes</textarea>
        <input type="button" value="get txt" onclick="go()" />
        <br />
        <p id="as">Now what</p>
    </div>
</form>
</body>

function go() {
    var c1 = document.getElementById('area1').value;
    var d1 = document.getElementById('as');
    d1.innerHTML = c1;
}

http://jsfiddle.net/PUpeJ/3/

Test or check if sheet exists

Compact wsExists function (without reliance on Error Handling!)

Here's a short & simple function that doesn't rely on error handling to determine whether a worksheet exists (and is properly declared to work in any situation!)

Function wsExists(wsName As String) As Boolean
    Dim ws: For Each ws In Sheets
    wsExists = (wsName = ws.Name): If wsExists Then Exit Function
    Next ws
End Function

Example Usage:

The following example adds a new worksheet named myNewSheet, if it doesn't already exist:

If Not wsExists("myNewSheet") Then Sheets.Add.Name = "myNewSheet"

More Information:

The RPC server is unavailable. (Exception from HRESULT: 0x800706BA)

Check to see if the Remote Procedure Call (RPC) service is running. If it is, then it's a firewall issue between your workstation and the server. You can test it by temporary disabling the firewall and retrying the command.

Edit after comment:

Ok, it's a firewall issue. You'll have to either limit the ports WMI/RPC work on, or open a lot of ports in the McAfee firewall.

Here are a few sites that explain this:

  1. Microsoft KB for limiting ports
  2. McAfee site talking about the same thing

Run JavaScript when an element loses focus

onblur is the opposite of onfocus.

python catch exception and continue try block

I don't think you want to do this. The correct way to use a try statement in general is as precisely as possible. I think it would be better to do:

try:
    do_smth1()
except Stmnh1Exception:
    # handle Stmnh1Exception

try:
    do_smth2()
except Stmnh2Exception:
    # handle Stmnh2Exception

Why does git say "Pull is not possible because you have unmerged files"?

If you want to pull down a remote branch to run locally (say for reviewing or testing purposes), and when you $ git pull you get local merge conflicts:

$ git checkout REMOTE-BRANCH
$ git pull  (you get local merge conflicts)
$ git reset --hard HEAD (discards local conflicts, and resets to remote branch HEAD)
$ git pull (now get remote branch updates without local conflicts)

What is the best way to add a value to an array in state

handleValueChange = (value) => {
      let myArr= [...this.state.myArr]
      myArr.push(value)
      this.setState({
         myArr
     })

This might do the work.

How do I copy directories recursively with gulp?

So - the solution of providing a base works given that all of the paths have the same base path. But if you want to provide different base paths, this still won't work.

One way I solved this problem was by making the beginning of the path relative. For your case:

gulp.src([
    'index.php',
    '*css/**/*',
    '*js/**/*',
    '*src/**/*',
])
.pipe(gulp.dest('/var/www/'));

The reason this works is that Gulp sets the base to be the end of the first explicit chunk - the leading * causes it to set the base at the cwd (which is the result that we all want!)

This only works if you can ensure your folder structure won't have certain paths that could match twice. For example, if you had randomjs/ at the same level as js, you would end up matching both.

This is the only way that I have found to include these as part of a top-level gulp.src function. It would likely be simple to create a plugin/function that could separate out each of those globs so you could specify the base directory for them, however.

How can I sort an ArrayList of Strings in Java?

Collections.sort(teamsName.subList(1, teamsName.size()));

The code above will reflect the actual sublist of your original list sorted.

HTML: How to make a submit button with text + image in it?

Please refer to this link. You can have any button you want just use javascript to submit the form

http://www.w3schools.com/jsref/met_form_submit.asp

Import an Excel worksheet into Access using VBA

Pass the sheet name with the Range parameter of the DoCmd.TransferSpreadsheet Method. See the box titled "Worksheets in the Range Parameter" near the bottom of that page.

This code imports from a sheet named "temp" in a workbook named "temp.xls", and stores the data in a table named "tblFromExcel".

Dim strXls As String
strXls = CurrentProject.Path & Chr(92) & "temp.xls"
DoCmd.TransferSpreadsheet acImport, , "tblFromExcel", _
    strXls, True, "temp!"

What does 'synchronized' mean?

synchronized simple means no two threads can access the block/method simultaneously. When we say any block/method of a class is synchronized it means only one thread can access them at a time. Internally the thread which tries to access it first take a lock on that object and as long as this lock is not available no other thread can access any of the synchronized methods/blocks of that instance of the class.

Note another thread can access a method of the same object which is not defined to be synchronized. A thread can release the lock by calling

Object.wait()

unbound method f() must be called with fibo_ instance as first argument (got classobj instance instead)

Differences in In python 2 and 3 version:

If you already have a default method in a class with same name and you re-declare as a same name it will appear as unbound-method call of that class instance when you wanted to instantiated it.

If you wanted class methods, but you declared them as instance methods instead.

An instance method is a method that is used when to create an instance of the class.

An example would be

   def user_group(self):   #This is an instance method
        return "instance method returning group"

Class label method:

   @classmethod
   def user_group(groups):   #This is an class-label method
        return "class method returning group"

In python 2 and 3 version differ the class @classmethod to write in python 3 it automatically get that as a class-label method and don't need to write @classmethod I think this might help you.

ORA-28001: The password has expired

I had same problem even after changing the password, it wasn't getting reflected in SQLDEVELOPER.

Atlast following solved my problem :

  1. Open Command Propmt
  2. Type sqlplus
  3. login as sysdba
  4. Run following command : alter user USERNAME identified by NEW_PASSWORD;

How to sort a dataFrame in python pandas by two or more columns?

For large dataframes of numeric data, you may see a significant performance improvement via numpy.lexsort, which performs an indirect sort using a sequence of keys:

import pandas as pd
import numpy as np

np.random.seed(0)

df1 = pd.DataFrame(np.random.randint(1, 5, (10,2)), columns=['a','b'])
df1 = pd.concat([df1]*100000)

def pdsort(df1):
    return df1.sort_values(['a', 'b'], ascending=[True, False])

def lex(df1):
    arr = df1.values
    return pd.DataFrame(arr[np.lexsort((-arr[:, 1], arr[:, 0]))])

assert (pdsort(df1).values == lex(df1).values).all()

%timeit pdsort(df1)  # 193 ms per loop
%timeit lex(df1)     # 143 ms per loop

One peculiarity is that the defined sorting order with numpy.lexsort is reversed: (-'b', 'a') sorts by series a first. We negate series b to reflect we want this series in descending order.

Be aware that np.lexsort only sorts with numeric values, while pd.DataFrame.sort_values works with either string or numeric values. Using np.lexsort with strings will give: TypeError: bad operand type for unary -: 'str'.

Timeout on a function call

I ran across this thread when searching for a timeout call on unit tests. I didn't find anything simple in the answers or 3rd party packages so I wrote the decorator below you can drop right into code:

import multiprocessing.pool
import functools

def timeout(max_timeout):
    """Timeout decorator, parameter in seconds."""
    def timeout_decorator(item):
        """Wrap the original function."""
        @functools.wraps(item)
        def func_wrapper(*args, **kwargs):
            """Closure for function."""
            pool = multiprocessing.pool.ThreadPool(processes=1)
            async_result = pool.apply_async(item, args, kwargs)
            # raises a TimeoutError if execution exceeds max_timeout
            return async_result.get(max_timeout)
        return func_wrapper
    return timeout_decorator

Then it's as simple as this to timeout a test or any function you like:

@timeout(5.0)  # if execution takes longer than 5 seconds, raise a TimeoutError
def test_base_regression(self):
    ...

Easy way to convert Iterable to Collection

With Guava you can use Lists.newArrayList(Iterable) or Sets.newHashSet(Iterable), among other similar methods. This will of course copy all the elements in to memory. If that isn't acceptable, I think your code that works with these ought to take Iterable rather than Collection. Guava also happens to provide convenient methods for doing things you can do on a Collection using an Iterable (such as Iterables.isEmpty(Iterable) or Iterables.contains(Iterable, Object)), but the performance implications are more obvious.

Checking whether a variable is an integer or not

If you want to check with no regard for Python version (2.x vs 3.x), use six (PyPI) and it's integer_types attribute:

import six

if isinstance(obj, six.integer_types):
    print('obj is an integer!')

Within six (a very light-weight single-file module), it's simply doing this:

import sys
PY3 = sys.version_info[0] == 3

if PY3:
    integer_types = int,
else:
    integer_types = (int, long)

Django REST Framework: adding additional field to ModelSerializer

I think SerializerMethodField is what you're looking for:

class FooSerializer(serializers.ModelSerializer):
  my_field = serializers.SerializerMethodField('is_named_bar')

  def is_named_bar(self, foo):
      return foo.name == "bar" 

  class Meta:
    model = Foo
    fields = ('id', 'name', 'my_field')

http://www.django-rest-framework.org/api-guide/fields/#serializermethodfield

How to combine results of two queries into a single dataset

How about,

select
        col1, 
        col2, 
        null col3, 
        null col4 
    from Table1
union all
select 
        null col1, 
        null col2,
        col4 col3, 
        col5 col4 
    from Table2;

How to change default text color using custom theme?

When you create an App, a file called styles.xml will be created in your res/values folder. If you change the styles, you can change the background, text color, etc for all your layouts. That way you don’t have to go into each individual layout and change the it manually.

styles.xml:

<resources xmlns:android="http://schemas.android.com/apk/res/android">
<style name="Theme.AppBaseTheme" parent="@android:style/Theme.Light">
    <item name="android:editTextColor">#295055</item> 
    <item name="android:textColorPrimary">#295055</item>
    <item name="android:textColorSecondary">#295055</item>
    <item name="android:textColorTertiary">#295055</item>
    <item name="android:textColorPrimaryInverse">#295055</item>
    <item name="android:textColorSecondaryInverse">#295055</item>
    <item name="android:textColorTertiaryInverse">#295055</item>

     <item name="android:windowBackground">@drawable/custom_background</item>        
</style>

<!-- Application theme. -->
<style name="AppTheme" parent="AppBaseTheme">
    <!-- All customizations that are NOT specific to a particular API-level can go here. -->
</style>

parent="@android:style/Theme.Light" is Google’s native colors. Here is a reference of what the native styles are: https://android.googlesource.com/platform/frameworks/base/+/refs/heads/master/core/res/res/values/themes.xml

The default Android style is also called “Theme”. So you calling it Theme probably confused the program.

name="Theme.AppBaseTheme" means that you are creating a style that inherits all the styles from parent="@android:style/Theme.Light". This part you can ignore unless you want to inherit from AppBaseTheme again. = <style name="AppTheme" parent="AppBaseTheme">

@drawable/custom_background is a custom image I put in the drawable’s folder. It is a 300x300 png image.

#295055 is a dark blue color.

My code changes the background and text color. For Button text, please look through Google’s native stlyes (the link I gave u above).

Then in Android Manifest, remember to include the code:

<application
android:theme="@style/Theme.AppBaseTheme">

How to open an elevated cmd using command line for Windows?

I use nirsoft programs (eg nircmdc) and sysinternals (eg psexec) all the time. They are very helpful.

But if you don't want to, or can't, dl a 3rd party program, here's another way, pure Windows.

Short answer: you can while elevated create a scheduled task with elevated privileges which you can then invoke later while not elevated.

Middle-length answer: while elevated create task with (but I prefer task scheduler GUI):

schtasks /create /sc once /tn cmd_elev /tr cmd /rl highest /st 00:00

Then later, no elevation needed, invoke with

schtasks /run /tn cmd_elev

Long answer: There's a lot of fidgety details; see my blog entry "Start program WITHOUT UAC, useful at system start and in batch files (use task scheduler)"

What size do you use for varchar(MAX) in your parameter declaration?

If you do something like this:

    cmd.Parameters.Add("@blah",SqlDbType.VarChar).Value = "some large text";

size will be taken from "some large text".Length

This can be problematic when it's an output parameter, you get back no more characters then you put as input.

Detecting installed programs via registry

User-specific settings should be written to HKCU\Software, machine-specific settings to HKLM\Software. Under these keys, structure [software vendor name]\[application name] (e.g. HKLM\Software\Microsoft\Internet Explorer) may be the most common, but that's just a convention, not a law of nature.

Many (most?) applications also add their uninstall entries to HKLM\Software\Microsoft\Windows\CurrentVersion\Uninstall\[app name], but again, not all applications do this.

These are the most important keys; however, contents of the registry do not have to represent the installed software exactly - maybe the application was installed once, but then was manually deleted, or maybe the uninstaller didn't remove all traces of it. If you want to be sure, check the filesystem to see if the application still exists where its registry entries say it is.

Edit:

If you're a member of the group Administrators, you can check the HKEY_USERS hive - each user's HKCU actually resides there (you'll need to know the user SID, or go through all of them).

Note: As @Brian Ensink says, "installed" is a bit of a vague concept - are we trying to find what the user could run? Some software doesn't even write to the Registry at all: search for "portable apps" to see apps that have been specifically modified to run directly from media (CD/USB) and not to leave any traces on the computer. We may also have to scan the disks, and network disks, and anything the user downloads, and world-accessible Windows shares in the Internet (yes, such things exist legitimately - \\live.sysinternals.com\tools comes to mind). In this direction, there's no real limit of what the user can run, unless prevented by system policies.

update query with join on two tables

this is Postgres UPDATE JOIN format:

UPDATE address 
SET cid = customers.id
FROM customers 
WHERE customers.id = address.id

Here's the other variations: http://mssql-to-postgresql.blogspot.com/2007/12/updates-in-postgresql-ms-sql-mysql.html

how do you pass images (bitmaps) between android activities using bundles?

Activity

To pass a bitmap between Activites

Intent intent = new Intent(this, Activity.class);
intent.putExtra("bitmap", bitmap);

And in the Activity class

Bitmap bitmap = getIntent().getParcelableExtra("bitmap");

Fragment

To pass a bitmap between Fragments

SecondFragment fragment = new SecondFragment();
Bundle bundle = new Bundle();
bundle.putParcelable("bitmap", bitmap);
fragment.setArguments(bundle);

To receive inside the SecondFragment

Bitmap bitmap = getArguments().getParcelable("bitmap");

Transferring large bitmap (Compress bitmap)

If you are getting failed binder transaction, this means you are exceeding the binder transaction buffer by transferring large element from one activity to another activity.

So in that case you have to compress the bitmap as an byte's array and then uncompress it in another activity, like this

In the FirstActivity

Intent intent = new Intent(this, SecondActivity.class);

ByteArrayOutputStream stream = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.JPG, 100, stream);
byte[] bytes = stream.toByteArray(); 
intent.putExtra("bitmapbytes",bytes);

And in the SecondActivity

byte[] bytes = getIntent().getByteArrayExtra("bitmapbytes");
Bitmap bmp = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);

forward declaration of a struct in C?

Try this

#include <stdio.h>

struct context;

struct funcptrs{
  void (*func0)(struct context *ctx);
  void (*func1)(void);
};

struct context{
    struct funcptrs fps;
}; 

void func1 (void) { printf( "1\n" ); }
void func0 (struct context *ctx) { printf( "0\n" ); }

void getContext(struct context *con){
    con->fps.func0 = func0;  
    con->fps.func1 = func1;  
}

int main(int argc, char *argv[]){
 struct context c;
   c.fps.func0 = func0;
   c.fps.func1 = func1;
   getContext(&c);
   c.fps.func0(&c);
   getchar();
   return 0;
}

Apache Tomcat :java.net.ConnectException: Connection refused

I also faced this problem . You can try any of these steps :

Can't connect to local MySQL server through socket homebrew

For me, I had installed mariadb long time ago, then installed [email protected].

When I executed mysql -uroot, I get the error: ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)

Reading the answers:

  • I uninstalled mariadb
  • Deleted the folder /usr/local/var/mysql
  • Ran the command mysqld --initialize

Then I was able to mysql -uroot -p

How to create custom exceptions in Java?

For a checked exception:

public class MyCustomException extends Exception { }

Technically, anything that extends Throwable can be an thrown, but exceptions are generally extensions of the Exception class so that they're checked exceptions (except RuntimeException or classes based on it, which are not checked), as opposed to the other common type of throwable, Errors which usually are not something designed to be gracefully handled beyond the JVM internals.

You can also make exceptions non-public, but then you can only use them in the package that defines them, as opposed to across packages.

As far as throwing/catching custom exceptions, it works just like the built-in ones - throw via

throw new MyCustomException()

and catch via

catch (MyCustomException e) { }

What's the best way to calculate the size of a directory in .NET?

var size = new DirectoryInfo("E:\\").GetDirectorySize();

and here's the code behind this Extension method

public static long GetDirectorySize(this System.IO.DirectoryInfo directoryInfo, bool recursive = true)
{
    var startDirectorySize = default(long);
    if (directoryInfo == null || !directoryInfo.Exists)
        return startDirectorySize; //Return 0 while Directory does not exist.

    //Add size of files in the Current Directory to main size.
    foreach (var fileInfo in directoryInfo.GetFiles())
        System.Threading.Interlocked.Add(ref startDirectorySize, fileInfo.Length);

    if (recursive) //Loop on Sub Direcotries in the Current Directory and Calculate it's files size.
        System.Threading.Tasks.Parallel.ForEach(directoryInfo.GetDirectories(), (subDirectory) =>
    System.Threading.Interlocked.Add(ref startDirectorySize, GetDirectorySize(subDirectory, recursive)));

    return startDirectorySize;  //Return full Size of this Directory.
}

How to resize array in C++?

The size of an array is static in C++. You cannot dynamically resize it. That's what std::vector is for:

std::vector<int> v; // size of the vector starts at 0

v.push_back(10); // v now has 1 element
v.push_back(20); // v now has 2 elements
v.push_back(30); // v now has 3 elements

v.pop_back(); // removes the 30 and resizes v to 2

v.resize(v.size() - 1); // resizes v to 1

Using the HTML5 "required" attribute for a group of checkboxes?

You don't need jQuery for this. Here's a vanilla JS proof of concept using an event listener on a parent container (checkbox-group-required) of the checkboxes, the checkbox element's .checked property and Array#some.

_x000D_
_x000D_
const validate = el => {
  const checkboxes = el.querySelectorAll('input[type="checkbox"]');
  return [...checkboxes].some(e => e.checked);
};

const formEl = document.querySelector("form");
const statusEl = formEl.querySelector(".status-message");
const checkboxGroupEl = formEl.querySelector(".checkbox-group-required");

checkboxGroupEl.addEventListener("click", e => {
  statusEl.textContent = validate(checkboxGroupEl) ? "valid" : "invalid";
});

formEl.addEventListener("submit", e => {
  e.preventDefault();
  
  if (validate(checkboxGroupEl)) {
    statusEl.textContent = "Form submitted!";
    // Send data from e.target to your backend
  }
  else {
    statusEl.textContent = "Error: select at least one checkbox";
  }
});
_x000D_
<form>
  <div class="checkbox-group-required">
    <input type="checkbox">
    <input type="checkbox">
    <input type="checkbox">
    <input type="checkbox">
  </div>
  <input type="submit" />
  <div class="status-message"></div>
</form>
_x000D_
_x000D_
_x000D_

If you have multiple groups to validate, add a loop over each group, optionally adding error messages or CSS to indicate which group fails validation:

_x000D_
_x000D_
const validate = el => {
  const checkboxes = el.querySelectorAll('input[type="checkbox"]');
  return [...checkboxes].some(e => e.checked);
};
const allValid = els => [...els].every(validate);

const formEl = document.querySelector("form");
const statusEl = formEl.querySelector(".status-message");
const checkboxGroupEls = formEl.querySelectorAll(".checkbox-group-required");

checkboxGroupEls.forEach(el =>
  el.addEventListener("click", e => {
    statusEl.textContent = allValid(checkboxGroupEls) ? "valid" : "invalid";
  })
);

formEl.addEventListener("submit", e => {
  e.preventDefault();
  
  if (allValid(checkboxGroupEls)) {
    statusEl.textContent = "Form submitted!";
  }
  else {
    statusEl.textContent = "Error: select at least one checkbox from each group";
  }
});
_x000D_
<form>
  <div class="checkbox-group-required">
    <label>
      Group 1:
      <input type="checkbox">
      <input type="checkbox">
      <input type="checkbox">
      <input type="checkbox">
    </label>
  </div>
  <div class="checkbox-group-required">
    <label>
      Group 2:
      <input type="checkbox">
      <input type="checkbox">
      <input type="checkbox">
      <input type="checkbox">
    </label>
  </div>
  <input type="submit" />
  <div class="status-message"></div>
</form>
_x000D_
_x000D_
_x000D_

How can you speed up Eclipse?

The only real way to hasten Eclipse with the standard plug-ins is to give it more memory and in some cases access to a faster storage space / defragmented hard drive.

Beyond that there is not much you can do performance-wise: most standard plug-ins do not have a continuous runtime cost, even Mylyn is relatively fast.

Upgrading to the latest JVM supported on your machine may help as well.

Some people downgrade to older Eclipse versions to get better performance. It may also make sense to use Eclipse classic instead of the official releases.

Typescript: React event types

To combine both Nitzan's and Edwin's answers, I found that something like this works for me:

update = (e: React.FormEvent<EventTarget>): void => {
    let target = e.target as HTMLInputElement;
    this.props.login[target.name] = target.value;
}

Conda command is not recognized on Windows 10

Even I got the same problem when I've first installed Anaconda. It said 'conda' command not found.

So I've just setup two values[added two new paths of Anaconda] system environment variables in the PATH variable which are: C:\Users\mshas\Anaconda2\ & C:\Users\mshas\Anaconda2\Scripts

Lot of people forgot to add the second variable which is "Scripts" just add that then 'conda' command works.

Parallel.ForEach vs Task.Factory.StartNew

I did a small experiment of running a method "1,000,000,000 (one billion)" times with "Parallel.For" and one with "Task" objects.

I measured the processor time and found Parallel more efficient. Parallel.For divides your task in to small work items and executes them on all the cores parallely in a optimal way. While creating lot of task objects ( FYI TPL will use thread pooling internally) will move every execution on each task creating more stress in the box which is evident from the experiment below.

I have also created a small video which explains basic TPL and also demonstrated how Parallel.For utilizes your core more efficiently http://www.youtube.com/watch?v=No7QqSc5cl8 as compared to normal tasks and threads.

Experiment 1

Parallel.For(0, 1000000000, x => Method1());

Experiment 2

for (int i = 0; i < 1000000000; i++)
{
    Task o = new Task(Method1);
    o.Start();
}

Processor time comparison

Git Commit Messages: 50/72 Formatting

Is the maximum recommended title length really 50?

I have believed this for years, but as I just noticed the documentation of "git commit" actually states

$ git help commit | grep -C 1 50
      Though not required, it’s a good idea to begin the commit message with
      a single short (less than 50 character) line summarizing the change,
      followed by a blank line and then a more thorough description. The text

$  git version
git version 2.11.0

One could argue that "less then 50" can only mean "no longer than 49".

How does "FOR" work in cmd batch file?

Couldn't resist throwing this out there, old as this thread is... Usually when the need arises to iterate through each of the files in PATH, all you really want to do is find a particular file... If that's the case, this one-liner will spit out the first directory it finds your file in:

(ex: looking for java.exe)

for %%x in (java.exe) do echo %%~dp$PATH:x

JSON and escaping characters

This is SUPER late and probably not relevant anymore, but if anyone stumbles upon this answer, I believe I know the cause.

So the JSON encoded string is perfectly valid with the degree symbol in it, as the other answer mentions. The problem is most likely in the character encoding that you are reading/writing with. Depending on how you are using Gson, you are probably passing it a java.io.Reader instance. Any time you are creating a Reader from an InputStream, you need to specify the character encoding, or java.nio.charset.Charset instance (it's usually best to use java.nio.charset.StandardCharsets.UTF_8). If you don't specify a Charset, Java will use your platform default encoding, which on Windows is usually CP-1252.

CodeIgniter PHP Model Access "Unable to locate the model you have specified"

Adding to @jakentus answer, below is what worked for me:

  1. Change the file name in the models package to Logon_model.php (First letter upper case as @jakentus correctly said)

  2. Change the class name as same as file name i.e.

    class Logon_model extends CI_Model

  3. Change the name in the load method too as

    $this->load->model('Logon_model');

Hope this helps. Happy coding. :)

How to uninstall Apache with command line

If Apache was installed using NSIS installer it should have left an uninstaller. You should search inside Apache installation directory for executable named unistaller.exe or something like that. NSIS uninstallers support /S flag by default for silent uninstall. So you can run something like "C:\Program Files\<Apache installation dir here>\uninstaller.exe" /S

From NSIS documentation:

3.2.1 Common Options

/NCRC disables the CRC check, unless CRCCheck force was used in the script. /S runs the installer or uninstaller silently. See section 4.12 for more information. /D sets the default installation directory ($INSTDIR), overriding InstallDir and InstallDirRegKey. It must be the last parameter used in the command line and must not contain any quotes, even if the path contains spaces. Only absolute paths are supported.

How to initialize/instantiate a custom UIView class with a XIB file in Swift

override func draw(_ rect: CGRect) 
{
    AlertView.layer.cornerRadius = 4
    AlertView.clipsToBounds = true

    btnOk.layer.cornerRadius = 4
    btnOk.clipsToBounds = true   
}

class func instanceFromNib() -> LAAlertView {
    return UINib(nibName: "LAAlertView", bundle: nil).instantiate(withOwner: nil, options: nil)[0] as! LAAlertView
}

@IBAction func okBtnDidClicked(_ sender: Any) {

    removeAlertViewFromWindow()

    UIView.animate(withDuration: 0.4, delay: 0.0, options: .allowAnimatedContent, animations: {() -> Void in
        self.AlertView.transform = CGAffineTransform(scaleX: 0.1, y: 0.1)

    }, completion: {(finished: Bool) -> Void in
        self.AlertView.transform = CGAffineTransform.identity
        self.AlertView.transform = CGAffineTransform(scaleX: 0.0, y: 0.0)
        self.AlertView.isHidden = true
        self.AlertView.alpha = 0.0

        self.alpha = 0.5
    })
}


func removeAlertViewFromWindow()
{
    for subview  in (appDel.window?.subviews)! {
        if subview.tag == 500500{
            subview.removeFromSuperview()
        }
    }
}


public func openAlertView(title:String , string : String ){

    lblTital.text  = title
    txtView.text  = string

    self.frame = CGRect(x: 0, y: 0, width: screenWidth, height: screenHeight)
    appDel.window!.addSubview(self)


    AlertView.alpha = 1.0
    AlertView.isHidden = false

    UIView.animate(withDuration: 0.2, animations: {() -> Void in
        self.alpha = 1.0
    })
    AlertView.transform = CGAffineTransform(scaleX: 0.0, y: 0.0)

    UIView.animate(withDuration: 0.3, delay: 0.2, options: .allowAnimatedContent, animations: {() -> Void in
        self.AlertView.transform = CGAffineTransform(scaleX: 1.1, y: 1.1)

    }, completion: {(finished: Bool) -> Void in
        UIView.animate(withDuration: 0.2, animations: {() -> Void in
            self.AlertView.transform = CGAffineTransform(scaleX: 1.0, y: 1.0)

        })
    })


}

Resizing image in Java

            int newHeight = 150;
            int newWidth = 150; 
            holder.iv_arrow.requestLayout();
            holder.iv_arrow.getLayoutParams().height = newHeight;
            holder.iv_arrow.getLayoutParams().width = newWidth;
            holder.iv_arrow.setScaleType(ImageView.ScaleType.FIT_XY);
            holder.iv_arrow.setImageResource(R.drawable.video_menu);

If...Then...Else with multiple statements after Then

Multiple statements are to be separated by a new line:

If SkyIsBlue Then
  StartEngines
  Pollute
ElseIf SkyIsRed Then
  StopAttack
  Vent
ElseIf SkyIsYellow Then
  If Sunset Then
    Sleep
  ElseIf Sunrise or IsMorning Then
    Smoke
    GetCoffee
  Else
    Error
  End If
Else
  Joke
  Laugh
End If

How to get all selected values from <select multiple=multiple>?

if you want as you expressed with breaks after each value;

$('#select-meal-type').change(function(){
    var meals = $(this).val();
    var selectedmeals = meals.join(", "); // there is a break after comma

    alert (selectedmeals); // just for testing what will be printed
})

Dynamically Add C# Properties at Runtime

Thanks @Clint for the great answer:

Just wanted to highlight how easy it was to solve this using the Expando Object:

    var dynamicObject = new ExpandoObject() as IDictionary<string, Object>;
    foreach (var property in properties) {
        dynamicObject.Add(property.Key,property.Value);
    }

HTTP URL Address Encoding in Java

You can use a function like this. Complete and modify it to your need :

/**
     * Encode URL (except :, /, ?, &, =, ... characters)
     * @param url to encode
     * @param encodingCharset url encoding charset
     * @return encoded URL
     * @throws UnsupportedEncodingException
     */
    public static String encodeUrl (String url, String encodingCharset) throws UnsupportedEncodingException{
            return new URLCodec().encode(url, encodingCharset).replace("%3A", ":").replace("%2F", "/").replace("%3F", "?").replace("%3D", "=").replace("%26", "&");
    }

Example of use :

String urlToEncode = ""http://www.growup.com/folder/intérieur-à_vendre?o=4";
Utils.encodeUrl (urlToEncode , "UTF-8")

The result is : http://www.growup.com/folder/int%C3%A9rieur-%C3%A0_vendre?o=4

Get full path of the files in PowerShell

I am using below script to extact all folder path:

Get-ChildItem -path "C:\" -Recurse -Directory -Force -ErrorAction SilentlyContinue | Select-Object FullName | Out-File "Folder_List.csv"

Full folder path is not coming. After 113 characters, is coming:

Example - C:\ProgramData\Microsoft\Windows\DeviceMetadataCache\dmrccache\en-US\ec4d5fdd-aa12-400f-83e2-7b0ea6023eb7\Windows...

Commit history on remote repository

Here's a bash function that makes it easy to view the logs on a remote. It takes two optional arguments. The first one is the branch, it defaults to master. The second one is the remote, it defaults to staging.

git_log_remote() {
  branch=${1:-master}
  remote=${2:-staging}
  
  git fetch $remote
  git checkout $remote/$branch
  git log
  git checkout -
}

examples:

 $ git_log_remote
 $ git_log_remote development origin

I'm getting Key error in python

This means your array is missing the key you're looking for. I handle this with a function which either returns the value if it exists or it returns a default value instead.

def keyCheck(key, arr, default):
    if key in arr.keys():
        return arr[key]
    else:
        return default


myarray = {'key1':1, 'key2':2}

print keyCheck('key1', myarray, '#default')
print keyCheck('key2', myarray, '#default')
print keyCheck('key3', myarray, '#default')

Output:

1
2
#default

Difference between drop table and truncate table?

DROP TABLE deletes the table.

TRUNCATE TABLE empties it, but leaves its structure for future data.

What does mvn install in maven exactly do

The install:install goal is provided by «Apache Maven Install Plugin»:

Apache Maven Install Plugin

The Install Plugin is used during the install phase to add artifact(s) to the local repository. The Install Plugin uses the information in the POM (groupId, artifactId, version) to determine the proper location for the artifact within the local repository.

The local repository is the local cache where all artifacts needed for the build are stored. By default, it is located within the user's home directory (~/.m2/repository) but the location can be configured in ~/.m2/settings.xml using the <localRepository> element.

Apache Maven Install Plugin - Introduction.

Having said that, the exact goal purpose:

install:install is used to automatically install the project's main artifact (the JAR, WAR or EAR), its POM and any attached artifacts (sources, javadoc, etc) produced by a particular project.

Apache Maven Install Plugin - Introduction.

For additional details on the goal, please refer to the Apache Maven Install Plugin - install:install page.

For additional details on the build lifecycle in general and on which place the goal has in the build lifecycle, please refer to the Maven – Introduction to the Build Lifecycle page.

How to call URL action in MVC with javascript function?

Try using the following on the JavaScript side:

window.location.href = '@Url.Action("Index", "Controller")';

If you want to pass parameters to the @Url.Action, you can do this:

var reportDate = $("#inputDateId").val();//parameter
var url = '@Url.Action("Index", "Controller", new {dateRequested = "findme"})';
window.location.href = url.replace('findme', reportDate);

How do I insert non breaking space character &nbsp; in a JSF page?

If your using the RichFaces library you can also use the tag rich:spacer which will add an "invisible" image with a given length and height. Usually much easier and prettier than to add tons of nbsp;.

Where you want your space to show you simply add:

<rich:spacer height="1" width="2" />

How to create web service (server & Client) in Visual Studio 2012?

WCF is a newer technology that is a viable alternative in many instances. ASP is great and works well, but I personally prefer WCF. And you can do it in .Net 4.5.

WCF Project

enter image description here

Create a new project. enter image description here Right-Click on the project in solution explorer, select "Add Service Reference" enter image description here

Create a textbox and button in the new application. Below is my click event for the button:

private void btnGo_Click(object sender, EventArgs e)
    {
        ServiceReference1.Service1Client testClient = new ServiceReference1.Service1Client();
        //Add error handling, null checks, etc...
        int iValue = int.Parse(txtInput.Text);
        string sResult = testClient.GetData(iValue).ToString();
        MessageBox.Show(sResult);
    }

And you're done. enter image description here

How does DHT in torrents work?

DHT nodes have unique identifiers, termed, Node ID. Node IDs are chosen at random from the same 160-bit space as BitTorrent info-hashes. Closeness is measured by comparing Node ID's routing tables, the closer the Node, the more detailed, resulting in optimal

What then makes them more optimal than it's predecessor "Kademlia" which used simple unsigned integers: distance(A,B) = |A xor B| Smaller values are closer. XOR. Besides not being secure, its logic was flawed.

If your client supports DHT, there are 8-bytes reserved in which contains 0x09 followed by a 2-byte payload with the UDP Port and DHT node. If the handshake is successful the above will continue.

How to create empty data frame with column names specified in R?

Perhaps:

> data.frame(aname=NA, bname=NA)[numeric(0), ]
[1] aname bname
<0 rows> (or 0-length row.names)

How to determine MIME type of file in android?

None of the answers here are perfect. Here is an answer combining the best elements of all the top answers:

public final class FileUtil {

    // By default, Android doesn't provide support for JSON
    public static final String MIME_TYPE_JSON = "application/json";

    @Nullable
    public static String getMimeType(@NonNull Context context, @NonNull Uri uri) {

        String mimeType = null;
        if (uri.getScheme().equals(ContentResolver.SCHEME_CONTENT)) {
            ContentResolver cr = context.getContentResolver();
            mimeType = cr.getType(uri);
        } else {
            String fileExtension = getExtension(uri.toString());

            if(fileExtension == null){
                return null;
            }

            mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(
                    fileExtension.toLowerCase());

            if(mimeType == null){
                // Handle the misc file extensions
                return handleMiscFileExtensions(fileExtension);
            }
        }
        return mimeType;
    }

    @Nullable
    private static String getExtension(@Nullable String fileName){

        if(fileName == null || TextUtils.isEmpty(fileName)){
            return null;
        }

        char[] arrayOfFilename = fileName.toCharArray();
        for(int i = arrayOfFilename.length-1; i > 0; i--){
            if(arrayOfFilename[i] == '.'){
                return fileName.substring(i+1, fileName.length());
            }
        }
        return null;
    }

    @Nullable
    private static String handleMiscFileExtensions(@NonNull String extension){

        if(extension.equals("json")){
            return MIME_TYPE_JSON;
        }
        else{
            return null;
        }
    }
}

Java swing application, close one window and open another when button is clicked

You can hide a part of JFrame that contains the swing controls which you want on another JFrame.

When the user clicks on a Jbutton the JFrame width increases and when he clicks on another same kind of Jbutton the JFrame comes to the default size.

  JFrame myFrame = new JFrame("");
  JButton button1 = new JButton("Basic");
  JButton button2 = new JButton("More options");
 // actionPerformed block code for button1 (Default size)  
 myFrame.setSize(400, 400);
//  actionPerformed block code for button2 (Increase width)
 myFrame.setSize(600, 400);

With jQuery, how do I capitalize the first letter of a text field while the user is still editing that field?

It's very cool you can capitalize Only the first letter of an input field With this one.. If any one know how to capitalize Like CSS text-transform:capitalize, Please Reply .. Here You go..

$('input-field').keyup(function(event) { $(this).val(($(this).val().substr(0,1).toUpperCase())+($(this).val().substr(1))); });

Unexpected token < in first line of HTML

Check your encoding, i got something similar once because of the BOM.

Make sure the core.js file is encoded in utf-8 without BOM

HTML - How to do a Confirmation popup to a Submit button and then send the request?

<script type='text/javascript'>

function foo() {


var user_choice = window.confirm('Would you like to continue?');


if(user_choice==true) {


window.location='your url';  // you can also use element.submit() if your input type='submit' 


} else {


return false;


}
}

</script>

<input type="button" onClick="foo()" value="save">

How to send a POST request in Go?

You have mostly the right idea, it's just the sending of the form that is wrong. The form belongs in the body of the request.

req, err := http.NewRequest("POST", url, strings.NewReader(form.Encode()))

Get last record of a table in Postgres

you can use

SELECT timestamp, value, card 
FROM my_table 
ORDER BY timestamp DESC 
LIMIT 1

assuming you want also to sort by timestamp?