Programs & Examples On #Coordinate transformation

Is the mathematical operation required to change from a coordinate system to another.

java.lang.NoClassDefFoundError: org/apache/juli/logging/LogFactory

aforementioned solutions did not help me, I could solve it by re-installing the Tomcat server which took few seconds.

Web link to specific whatsapp contact

This approach only works on Android AND if you have the number on your contact list. If you don't have it, Android opens your SMS app, so you can invite the contact to use Whatsapp.

<a href="https://api.whatsapp.com/send?phone=2567xxxxxxxxx" method="get" target="_blank"><i class="fa fa-whatsapp"></i></a>

Google Chrome am targeting a blank window

Unknown column in 'field list' error on MySQL Update query

In my case, it was caused by an unseen trailing space at the end of the column name. Just check if you really use "y" or "y " instead.

How to increase request timeout in IIS?

In IIS >= 7, a <webLimits> section has replaced ConnectionTimeout, HeaderWaitTimeout, MaxGlobalBandwidth, and MinFileBytesPerSec IIS 6 metabase settings.

Example Configuration:

<configuration>
   <system.applicationHost>
      <webLimits connectionTimeout="00:01:00"
         dynamicIdleThreshold="150"
         headerWaitTimeout="00:00:30"
         minBytesPerSecond="500"
      />
   </system.applicationHost>
</configuration>

For reference: more information regarding these settings in IIS can be found here. Also, I was unable to add this section to the web.config via the IIS manager's "configuration editor", though it did show up once I added it and searched the configuration.

What is __init__.py for?

An __init__.py file makes imports easy. When an __init__.py is present within a package, function a() can be imported from file b.py like so:

from b import a

Without it, however, you can't import directly. You have to amend the system path:

import sys
sys.path.insert(0, 'path/to/b.py')

from b import a

Facebook OAuth "The domain of this URL isn't included in the app's domain"

I had the same problem.....the issu is in the version PHP SDK 5.6.2 and the fix was editing the following file:

facebook\src\Facebook\Helpers\FacebookRedirectLoginHelper.php

change this line

$redirectUrl = FacebookUrlManipulator::removeParamsFromUrl($redirectUrl,['state','code']);

to

$redirectUrl = FacebookUrlManipulator::removeParamsFromUrl($redirectUrl,['state','code','enforce_https']);

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

I encountered the same "Exception from HRESULT: 0x800706BA" error with get-wmiobject -computerName remoteserverName -class win32_logicaldisk. The remote server is an AWS EC2 instance in my case. The Windows server firewall has WMI ports open. SecurityGroup attached to the EC2 instance has common RPC ports (tcp/udp 135-139, 49152 - 65535) inbound allowed.

I then ran netstat -a -b |findstr remoteServerName after kick off the get-wmiobject powershell command. Turns out the command was trying hit tcp port 6402 on the remote server! After added tcp 6402 into its Security Group inbound rule, get-wmiobject works perfectly! It appears the remote server has WMI set to a fixed port!

So if you checked all usual firewall rules and stil having problem with WMI, try use netstat to identify which port the command is actually trying to hit.

Get first date of current month in java

In Java 8 you can use:

LocalDate date = LocalDate.now(); //2020-01-12
date.withDayOfMonth(1); //2020-01-01

graphing an equation with matplotlib

To plot an equation that is not solved for a specific variable (like circle or hyperbola):

import numpy as np  
import matplotlib.pyplot as plt  
plt.figure() # Create a new figure window
xlist = np.linspace(-2.0, 2.0, 100) # Create 1-D arrays for x,y dimensions
ylist = np.linspace(-2.0, 2.0, 100) 
X,Y = np.meshgrid(xlist, ylist) # Create 2-D grid xlist,ylist values
F = X**2 + Y**2 - 1  #  'Circle Equation
plt.contour(X, Y, F, [0], colors = 'k', linestyles = 'solid')
plt.show()

More about it: http://courses.csail.mit.edu/6.867/wiki/images/3/3f/Plot-python.pdf

How to Troubleshoot Intermittent SQL Timeout Errors

I am experiencing the same issue.. and I build some logging into several functions that I could identify that were frequently running long. when I say frequently I mean about 2% of the time. So part of the log inserted the start time and the end time of the procedure or query. I then produced a simple report sorting several days of logs by the total execution time descending. here is what I found.

the long running instances always started between HH:00 and HH:02 or HH:30 an HH:32 and none of the short running queries ran between those times. Interesting....

Now It seems that there is actually more order to the chaos that I was experiencing. I was using a recovery target of 0 this implemented "indirect checkpoints" in my databases so that my recovery time could be achieved at nearly 1 minute. causing these checkpoints to be created every 30 mins.

WOW, what a coincidence!

In Microsoft's online documentation about changing the recovery time of a database comes with this little warning...

"An online transactional workload on a database that is configured for indirect checkpoints could experience performance degradation."

Wow go figure...

so I modified my recovery time and bango no more issues.

Cannot implicitly convert type 'System.Linq.IQueryable' to 'System.Collections.Generic.IList'

Try this -->

 new DzieckoAndOpiekun(
                         p.Imie,
                         p.Nazwisko,
                         p.Opiekun.Imie,
                         p.Opiekun.Nazwisko).ToList()

mongodb, replicates and error: { "$err" : "not master and slaveOk=false", "code" : 13435 }

in mongodb2.0

you should type

rs.slaveOk()

in secondary mongod node

Squash my last X commits together using Git

In the branch you would like to combine the commits on, run:

git rebase -i HEAD~(n number of commits back to review)

example:

git rebase -i HEAD~1

This will open the text editor and you must switch the 'pick' in front of each commit with 'squash' if you would like these commits to be merged together. From documentation:

p, pick = use commit

s, squash = use commit, but meld into previous commit

For example, if you are looking to merge all the commits into one, the 'pick' is the first commit you made and all future ones (placed below the first) should be set to 'squash'. If using vim, use :x in insert mode to save and exit the editor.

Then to continue the rebase:

git rebase --continue

For more on this and other ways to rewrite your commit history see this helpful post

How to sort by dates excel?

It's actually really easy. Highlight the DATE column and make sure that its set as date in Excel. Highlight everything you want to change, Then go to [DATA]>[SORT]>[COLUMN] and set sorting by date. Hope it helps.

How to display HTML in TextView?

Simple use Html.fromHtml("html string"). This will work. If the string has tags like <h1> then spaces will come. But we cannot eliminate those spaces. If you still want to remove the spaces, then you can remove the tags in the string and then pass the string to the method Html.fromHtml("html string"); . Also generally these strings come from server(dynamic) but not often, if it is the case better to pass the string as it is to the method than try to remove the tags from the string.

Extract directory path and filename

Using bash "here string":

$ fspec="/exp/home1/abc.txt" 
$ tr  "/"  "\n"  <<< $fspec | tail -1
abc.txt
$ filename=$(tr  "/"  "\n"  <<< $fspec | tail -1)
$ echo $filename
abc.txt

The benefit of the "here string" is that it avoids the need/overhead of running an echo command. In other words, the "here string" is internal to the shell. That is:

$ tr <<< $fspec

as opposed to:

$ echo $fspec | tr

error: unknown type name ‘bool’

C90 does not support the boolean data type.

C99 does include it with this include:

#include <stdbool.h>

Difference between null and empty ("") Java String

In Java a reference type assigned null has no value at all. A string assigned "" has a value: an empty string, which is to say a string with no characters in it. When a variable is assigned null it means there is no underlying object of any kind, string or otherwise.

Calling a java method from c++ in Android

If it's an object method, you need to pass the object to CallObjectMethod:

jobject result = env->CallObjectMethod(obj, messageMe, jstr);

What you were doing was the equivalent of jstr.messageMe().

Since your is a void method, you should call:

env->CallVoidMethod(obj, messageMe, jstr);

If you want to return a result, you need to change your JNI signature (the ()V means a method of void return type) and also the return type in your Java code.

how to make jni.h be found?

I don't know if this applies in this case, but sometimes the file got deleted for unknown reasons, copying it again into the respective folder should resolve the problem.

Print debugging info from stored procedure in MySQL

I usually create log table with a stored procedure to log to it. The call the logging procedure wherever needed from the procedure under development.

Looking at other posts on this same question, it seems like a common practice, although there are some alternatives.

Oracle SQL Where clause to find date records older than 30 days

Use:

SELECT *
  FROM YOUR_TABLE
 WHERE creation_date <= TRUNC(SYSDATE) - 30

SYSDATE returns the date & time; TRUNC resets the date to being as of midnight so you can omit it if you want the creation_date that is 30 days previous including the current time.

Depending on your needs, you could also look at using ADD_MONTHS:

SELECT *
  FROM YOUR_TABLE
 WHERE creation_date <= ADD_MONTHS(TRUNC(SYSDATE), -1)

Difference between $(document.body) and $('body')

The answers here are not actually completely correct. Close, but there's an edge case.

The difference is that $('body') actually selects the element by the tag name, whereas document.body references the direct object on the document.

That means if you (or a rogue script) overwrites the document.body element (shame!) $('body') will still work, but $(document.body) will not. So by definition they're not equivalent.

I'd venture to guess there are other edge cases (such as globally id'ed elements in IE) that would also trigger what amounts to an overwritten body element on the document object, and the same situation would apply.

Javascript change date into format of (dd/mm/yyyy)

This will ensure you get a two-digit day and month.

function formattedDate(d = new Date) {
  let month = String(d.getMonth() + 1);
  let day = String(d.getDate());
  const year = String(d.getFullYear());

  if (month.length < 2) month = '0' + month;
  if (day.length < 2) day = '0' + day;

  return `${day}/${month}/${year}`;
}

Or terser:

function formattedDate(d = new Date) {
  return [d.getDate(), d.getMonth()+1, d.getFullYear()]
      .map(n => n < 10 ? `0${n}` : `${n}`).join('/');
}

htaccess remove index.php from url

For more detail

create .htaccess file on project root directory and put below code for remove index.php

  RewriteEngine on
  RewriteCond $1 !^(index.php|resources|robots.txt)
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteRule ^(.*)$ index.php/$1 [L,QSA]

Run a PHP file in a cron job using CPanel

This works fine and also sends email:

/usr/bin/php /home/xxYourUserNamexx/public_html/xxYourFolderxx/xxcronfile.php

The following two commands also work fine but do not send email:

/usr/bin/php -f /home/Same As Above

php -f /home/Same As Above

In reactJS, how to copy text to clipboard?

Your code should work perfectly, I use it the same way. Only make sure that if the click event is triggered from within a pop up screen like a bootstrap modal or something, the created element has to be within that modal otherwise it won't copy. You could always give the id of an element within that modal (as a second parameter) and retrieve it with getElementById, then append the newly created element to that one instead of the document. Something like this:

copyToClipboard = (text, elementId) => {
  const textField = document.createElement('textarea');
  textField.innerText = text;
  const parentElement = document.getElementById(elementId);
  parentElement.appendChild(textField);
  textField.select();
  document.execCommand('copy');
  parentElement.removeChild(textField);
}

How do I check in JavaScript if a value exists at a certain array index?

OK, let's first see what would happens if an array value not exist in JavaScript, so if we have an array like below:

const arr = [1, 2, 3, 4, 5];

and now we check if 6 is there at index 5 or not:

arr[5];

and we get undefined...

So that's basically give us the answer, the best way to check if undefined, so something like this:

if("undefined" === typeof arrayName[index]) {
  //array value is not there...
}

It's better NOT doing this in this case:

if(!arrayName[index]) {
  //Don't check like this..
}

Because imagine we have this array:

const arr = [0, 1, 2];

and we do:

if(!arr[0]) {
  //This get passed, because in JavaScript 0 is falsy
}

So as you see, even 0 is there, it doesn't get recognised, there are few other things which can do the same and make you application buggy, so be careful, I list them all down:

  1. undefined: if the value is not defined and it's undefined
  2. null: if it's null, for example if a DOM element not exists...
  3. empty string: ''
  4. 0: number zero
  5. NaN: not a number
  6. false

How to vertically align into the center of the content of a div with defined width/height?

margin: all_four_margin

by providing 50% to all_four_margin will place the element at the center

style="margin: 50%"

you can apply it for following too

margin: top right bottom left

margin: top right&left bottom

margin: top&bottom right&left

by giving appropriate % we get the element wherever we want.

How to search a string in multiple files and return the names of files in Powershell?

This should give the location of the files that contain your pattern:

Get-ChildItem -Recurse | Select-String "dummy" -List | Select Path

When to create variables (memory management)

So notice variables are on the stack, the values they refer to are on the heap. So having variables is not too bad but yes they do create references to other entities. However in the simple case you describe it's not really any consequence. If it is never read again and within a contained scope, the compiler will probably strip it out before runtime. Even if it didn't the garbage collector will be able to safely remove it after the stack squashes. If you are running into issues where you have too many stack variables, it's usually because you have really deep stacks. The amount of stack space needed per thread is a better place to adjust than to make your code unreadable. The setting to null is also no longer needed

Disabling Chrome Autofill

Thought i'd post my fix. Found that you can't use display:none so i came up with a quick and dirty solution to just make the fake input small and move it out of sight. So far so good until they break it again.

_x000D_
_x000D_
                    <input id="FakePassword" type="password" style="float:left;position:relative;height:0;width:0;top:-1000px;left:-1000px;" />
_x000D_
_x000D_
_x000D_

dll missing in JDBC

If its the case of the dll file missing you can download the dll file from this link http://en.osdn.jp/projects/sfnet_dose-grok/downloads/sqljdbc_auth.dll/

else you need to provide the username and password of the db you are trying to connect, and make the authentication as false

Convert number to month name in PHP

Use:

$name = jdmonthname(gregoriantojd($monthNumber, 1, 1), CAL_MONTH_GREGORIAN_LONG);

Differences between Oracle JDK and OpenJDK

My understanding is that Oracle JDK can't be used in production, therefore I cannot legally use it (without paying), for the web application I am building for my company. I have to use OpenJDK. Please correct me if I am wrong! From this article.

Starting with Java 11, the Oracle JDK is restricted to development and testing environments. Oracle JDKs may only be used in production if you buy the commercial support. Instead, Oracle will provide Java builds based on OpenJDK for free which can be used in production. But for the official Oracle JDK the real roadmap will look like this:

UPDATE: I'm wrong. I can use Oracle JDK for free but won't get security updates after 6 mos and we'll have to assume the risk. Look at the above linked article section "What does the new release train mean to my company?".

What is a callback?

A callback is a function that will be called when a process is done executing a specific task.

The usage of a callback is usually in asynchronous logic.

To create a callback in C#, you need to store a function address inside a variable. This is achieved using a delegate or the new lambda semantic Func or Action.

    public delegate void WorkCompletedCallBack(string result);

    public void DoWork(WorkCompletedCallBack callback)
    {
        callback("Hello world");
    }

    public void Test()
    {
        WorkCompletedCallBack callback = TestCallBack; // Notice that I am referencing a method without its parameter
        DoWork(callback);
    }

    public void TestCallBack(string result)
    {
        Console.WriteLine(result);
    }

In today C#, this could be done using lambda like:

    public void DoWork(Action<string> callback)
    {
        callback("Hello world");
    }

    public void Test()
    {
        DoWork((result) => Console.WriteLine(result));
    }

Oracle 11g SQL to get unique values in one column of a multi-column query

This will be more efficient, plus you have control over the ordering it uses to pick a value:

SELECT DISTINCT
       FIRST_VALUE(person)
          OVER(PARTITION BY language
               ORDER BY person)
      ,language
FROM   tableA;

If you really don't care which person is picked for each language, you can omit the ORDER BY clause:

SELECT DISTINCT
       FIRST_VALUE(person)
          OVER(PARTITION BY language)
      ,language
FROM   tableA;

Spark - repartition() vs coalesce()

But also you should make sure that, the data which is coming coalesce nodes should have highly configured, if you are dealing with huge data. Because all the data will be loaded to those nodes, may lead memory exception. Though reparation is costly, i prefer to use it. Since it shuffles and distribute the data equally.

Be wise to select between coalesce and repartition.

Change URL without refresh the page

Update

Based on Manipulating the browser history, passing the empty string as second parameter of pushState method (aka title) should be safe against future changes to the method, so it's better to use pushState like this:

history.pushState(null, '', '/en/step2');    

You can read more about that in mentioned article

Original Answer

Use history.pushState like this:

history.pushState(null, null, '/en/step2');

Update 2 to answer Idan Dagan's comment:

Why not using history.replaceState()?

From MDN

history.replaceState() operates exactly like history.pushState() except that replaceState() modifies the current history entry instead of creating a new one

That means if you use replaceState, yes the url will be changed but user can not use Browser's Back button to back to prev. state(s) anymore (because replaceState doesn't add new entry to history) and it's not recommended and provide bad UX.

Update 3 to add window.onpopstate

So, as this answer got your attention, here is additional info about manipulating the browser history, after using pushState, you can detect the back/forward button navigation by using window.onpopstate like this:

window.onpopstate = function(e) {
    // ... 
};

As the first argument of pushState is an object, if you passed an object instead of null, you can access that object in onpopstate which is very handy, here is how:

window.onpopstate = function(e) {
    if(e.state) {
        console.log(e.state);
    }
};

Update 4 to add Reading the current state:

When your page loads, it might have a non-null state object, you can read the state of the current history entry without waiting for a popstate event using the history.state property like this:

console.log(history.state);

Bonus: Use following to check history.pushState support:

if (history.pushState) {
  // \o/
}

How to assign text size in sp value using java code

When the accepted answer doesn't work (for example when dealing with Paint) you can use:

float spTextSize = 12;
float textSize = spTextSize * getResources().getDisplayMetrics().scaledDensity;
textPaint.setTextSize(textSize);

How can I develop for iPhone using a Windows development machine?

Using Xamarin now we can develop iPhone applications in Windows machine itself with the help of Xamarin Live Player.

Using this Xamarin live player dev/deploy/debug cycle can now be done without an Apple system.

But to sign and release the app Apple system is required.

Find the reference here

I checked the reference nothing dodgy

Forwarding port 80 to 8080 using NGINX

This worked for me:

server {
  listen  80; 
  server_name example.com www.example.com;

  location / { 
    proxy_pass                          http://127.0.0.1:8080/;
    proxy_set_header Host               $host;
    proxy_set_header X-Real-IP          $remote_addr;  
    proxy_set_header X-Forwarded-For    $proxy_add_x_forwarded_for;
  }
}

If it does not work for you look at the logs at sudo tail -f /var/log/nginx/error.log

Are HTTP cookies port specific?

The current cookie specification is RFC 6265, which replaces RFC 2109 and RFC 2965 (both RFCs are now marked as "Historic") and formalizes the syntax for real-world usages of cookies. It clearly states:

  1. Introduction

...

For historical reasons, cookies contain a number of security and privacy infelicities. For example, a server can indicate that a given cookie is intended for "secure" connections, but the Secure attribute does not provide integrity in the presence of an active network attacker. Similarly, cookies for a given host are shared across all the ports on that host, even though the usual "same-origin policy" used by web browsers isolates content retrieved via different ports.

And also:

8.5. Weak Confidentiality

Cookies do not provide isolation by port. If a cookie is readable by a service running on one port, the cookie is also readable by a service running on another port of the same server. If a cookie is writable by a service on one port, the cookie is also writable by a service running on another port of the same server. For this reason, servers SHOULD NOT both run mutually distrusting services on different ports of the same host and use cookies to store security sensitive information.

Getting value of select (dropdown) before change

Track the value by hand.

var selects = jQuery("select.track_me");

selects.each(function (i, element) {
  var select = jQuery(element);
  var previousValue = select.val();
  select.bind("change", function () {
    var currentValue = select.val();

    // Use currentValue and previousValue
    // ...

    previousValue = currentValue;
  });
});

Find the min/max element of an array in JavaScript

Others have already given some solutions in which they augment Array.prototype. All I want in this answer is to clarify whether it should be Math.min.apply( Math, array ) or Math.min.apply( null, array ). So what context should be used, Math or null?

When passing null as a context to apply, then the context will default to the global object (the window object in the case of browsers). Passing the Math object as the context would be the correct solution, but it won't hurt passing null either. Here's an example when null might cause trouble, when decorating the Math.max function:

// decorate Math.max
(function (oldMax) {
    Math.max = function () {
        this.foo(); // call Math.foo, or at least that's what we want

        return oldMax.apply(this, arguments);
    };
})(Math.max);

Math.foo = function () {
    print("foo");
};

Array.prototype.max = function() {
  return Math.max.apply(null, this); // <-- passing null as the context
};

var max = [1, 2, 3].max();

print(max);

The above will throw an exception because this.foo will be evaluated as window.foo, which is undefined. If we replace null with Math, things will work as expected and the string "foo" will be printed to the screen (I tested this using Mozilla Rhino).

You can pretty much assume that nobody has decorated Math.max so, passing null will work without problems.

TypeError: expected str, bytes or os.PathLike object, not _io.BufferedReader

I think it has to do with your second element in storbinary. You are trying to open file, but it is already a pointer to the file you opened in line file = open(local_path,'rb'). So, try to use ftp.storbinary("STOR " + i, file).

How can I render inline JavaScript with Jade / Pug?

No use script tag only.

Solution with |:

script
  | if (10 == 10) {
  |   alert("working")
  | }

Or with a .:

script.
  if (10 == 10) {
    alert("working")
  }

Log4j output not displayed in Eclipse console

Thought this was a genuine defect but it turns out that my console size was limited, and caused the old content past 80000 characters to be cut off.

Right click on the console for the preferences and increase the console size limit.

How do I decode a string with escaped unicode?

I don't have enough rep to put this under comments to the existing answers:

unescape is only deprecated for working with URIs (or any encoded utf-8) which is probably the case for most people's needs. encodeURIComponent converts a js string to escaped UTF-8 and decodeURIComponent only works on escaped UTF-8 bytes. It throws an error for something like decodeURIComponent('%a9'); // error because extended ascii isn't valid utf-8 (even though that's still a unicode value), whereas unescape('%a9'); // © So you need to know your data when using decodeURIComponent.

decodeURIComponent won't work on "%C2" or any lone byte over 0x7f because in utf-8 that indicates part of a surrogate. However decodeURIComponent("%C2%A9") //gives you © Unescape wouldn't work properly on that // © AND it wouldn't throw an error, so unescape can lead to buggy code if you don't know your data.

How can I set the font-family & font-size inside of a div?

Append a semicolon to the following line to fix the issue.

font-family:    Arial, Helvetica, sans-serif;

How to change navbar/container width? Bootstrap 3

I just solved this issue myself. You were on the right track.

@media (min-width: 1200px) {
    .container{
        max-width: 970px;
    }
}

Here we say: On viewports 1200px or larger - set container max-width to 970px. This will overwrite the standard class that currently sets max-width to 1170px for that range.

NOTE: Make sure you include this AFTER the bootstrap.css stuff (everyone has made this little mistake in the past).

Hope this helps.. good luck!

Escaping ampersand character in SQL string

You can use

set define off

Using this it won't prompt for the input

Can I set up HTML/Email Templates with ASP.NET?

Be careful when doing this, SPAM filters seem to block ASP.net generated html, apparently because of ViewState, so if you are going to do this make sure the Html produced is clean.

I personally would look into using Asp.net MVC to achieve your desired results. or NVelocity is quite good at this

Deploying just HTML, CSS webpage to Tomcat

There is no real need to create a war to run it from Tomcat. You can follow these steps

  1. Create a folder in webapps folder e.g. MyApp

  2. Put your html and css in that folder and name the html file, which you want to be the starting page for your application, index.html

  3. Start tomcat and point your browser to url "http://localhost:8080/MyApp". Your index.html page will pop up in the browser

pandas dataframe columns scaling with sklearn

I know it's a very old comment, but still:

Instead of using single bracket (dfTest['A']), use double brackets (dfTest[['A']]).

i.e: min_max_scaler.fit_transform(dfTest[['A']]).

I believe this will give the desired result.

Apache 2.4.6 on Ubuntu Server: Client denied by server configuration (PHP FPM) [While loading PHP file]

For those of you on AWS (Amazon Web Services), remember to add a rule for your SSL port (in my case 443) to your security groups. I was getting this error because I forgot to open the port.

3 hours of tearing my hair out later...

OS X Sprite Kit Game Optimal Default Window Size

You should target the smallest, not the largest, supported pixel resolution by the devices your app can run on.

Say if there's an actual Mac computer that can run OS X 10.9 and has a native screen resolution of only 1280x720 then that's the resolution you should focus on. Any higher and your game won't correctly run on this device and you could as well remove that device from your supported devices list.

You can rely on upscaling to match larger screen sizes, but you can't rely on downscaling to preserve possibly important image details such as text or smaller game objects.

The next most important step is to pick a fitting aspect ratio, be it 4:3 or 16:9 or 16:10, that ideally is the native aspect ratio on most of the supported devices. Make sure your game only scales to fit on devices with a different aspect ratio.

You could scale to fill but then you must ensure that on all devices the cropped areas will not negatively impact gameplay or the use of the app in general (ie text or buttons outside the visible screen area). This will be harder to test as you'd actually have to have one of those devices or create a custom build that crops the view accordingly.

Alternatively you can design multiple versions of your game for specific and very common screen resolutions to provide the best game experience from 13" through 27" displays. Optimized designs for iMac (desktop) and a Macbook (notebook) devices make the most sense, it'll be harder to justify making optimized versions for 13" and 15" plus 21" and 27" screens.

But of course this depends a lot on the game. For example a tile-based world game could simply provide a larger viewing area onto the world on larger screen resolutions rather than scaling the view up. Provided that this does not alter gameplay, like giving the player an unfair advantage (specifically in multiplayer).

You should provide @2x images for the Retina Macbook Pro and future Retina Macs.

Root element is missing

I had the same problem when i have trying to read xml that was extracted from archive to memory stream.

 MemoryStream SubSetupStream = new MemoryStream();
        using (ZipFile archive = ZipFile.Read(zipPath))
        {
            archive.Password = "SomePass";
            foreach  (ZipEntry file in archive)
            {
                file.Extract(SubSetupStream);
            }
        }

Problem was in these lines:

XmlDocument doc = new XmlDocument();
    doc.Load(SubSetupStream);

And solution is (Thanks to @Phil):

        if (SubSetupStream.Position>0)
        {
            SubSetupStream.Position = 0;
        }

How to maintain aspect ratio using HTML IMG tag

Use object-fit: contain in css of html element img.

ex:

img {
    ...
    object-fit: contain
    ...
}

How to extract numbers from a string in Python?

To catch different patterns it is helpful to query with different patterns.

Setup all the patterns that catch different number patterns of interest:

(finds commas) 12,300 or 12,300.00

'[\d]+[.,\d]+'

(finds floats) 0.123 or .123

'[\d]*[.][\d]+'

(finds integers) 123

'[\d]+'

Combine with pipe ( | ) into one pattern with multiple or conditionals.

(Note: Put complex patterns first else simple patterns will return chunks of the complex catch instead of the complex catch returning the full catch).

p = '[\d]+[.,\d]+|[\d]*[.][\d]+|[\d]+'

Below, we'll confirm a pattern is present with re.search(), then return an iterable list of catches. Finally, we'll print each catch using bracket notation to subselect the match object return value from the match object.

s = 'he33llo 42 I\'m a 32 string 30 444.4 12,001'

if re.search(p, s) is not None:
    for catch in re.finditer(p, s):
        print(catch[0]) # catch is a match object

Returns:

33
42
32
30
444.4
12,001

PHP - If variable is not empty, echo some html code

Your problem is in your use of the_field(), which is for Advanced Custom Fields, a wordpress plugin.

If you want to use a field in a variable you have to use this: $web = get_field('website');.

How can I remount my Android/system as read-write in a bash script using adb?

mount -o rw,remount $(mount | grep /dev/root | awk '{print $3}')

this does the job for me, and should work for any android version.

Relative URLs in WordPress

I solved it in my site making this in functions.php

add_action("template_redirect", "start_buffer");
add_action("shutdown", "end_buffer", 999);

function filter_buffer($buffer) {
    $buffer = replace_insecure_links($buffer);
    return $buffer;
}
function start_buffer(){
    ob_start("filter_buffer");
}

function end_buffer(){
    if (ob_get_length()) ob_end_flush();
}

function replace_insecure_links($str) {

   $str = str_replace ( array("http://www.yoursite.com/", "https://www.yoursite.com/") , array("/", "/"), $str);

   return apply_filters("rsssl_fixer_output", $str);

}

I took part of one plugin, cut it into pieces and make this. It replaced ALL links in my site (menus, css, scripts etc.) and everything was working.

:first-child not working as expected

you can also use

.detail_container h1:nth-of-type(1)

By changing the number 1 by any other number you can select any other h1 item.

How do I remove link underlining in my HTML email?

You can do "redundant styling" and that should fix the issue. You use the same styling you have on the but add it to a that is within the .

Example:

<td width="110" align="center" valign="top" style="color:#000000;">
    <a href="https://example.com" target="_blank"
       style="color:#000000; text-decoration:none;"><span style="color:#000000; text-decoration:none;">BOOK NOW</span></a>
</td>

How can I set response header on express.js assets

There is at least one middleware on npm for handling CORS in Express: cors.

Escape double quotes in parameter

I cannot quickly reproduce the symptoms: if I try myscript '"test"' with a batch file myscript.bat containing just @echo.%1 or even @echo.%~1, I get all quotes: '"test"'

Perhaps you can try the escape character ^ like this: myscript '^"test^"'?

Difference between DTO, VO, POJO, JavaBeans?

POJO : It is a java file(class) which doesn't extend or implement any other java file(class).

Bean: It is a java file(class) in which all variables are private, methods are public and appropriate getters and setters are used for accessing variables.

Normal class: It is a java file(class) which may consist of public/private/default/protected variables and which may or may not extend or implement another java file(class).

Swift_TransportException Connection could not be established with host smtp.gmail.com

If you have hosted your website already it advisable to use the email or create an offical mail to send the email Let say your url is www.example.com. Then go to the cpanel create an email which will be [email protected]. Then request for the setting of the email. Change the email address to [email protected]. Then change your smtp which will be mail.example.com. The ssl will remain 465

Populating a razor dropdownlist from a List<object> in MVC

I'm going to approach this as if you have a Users model:

Users.cs

public class Users
{
    [Key]
    public int UserId { get; set; }

    [Required]
    public string UserName { get; set; }

    public int RoleId { get; set; }

    [ForeignKey("RoleId")]
    public virtual DbUserRoles DbUserRoles { get; set; }
}

and a DbUserRoles model that represented a table by that name in the database:

DbUserRoles.cs

public partial class DbUserRoles
{
    [Key]
    public int UserRoleId { get; set; }

    [Required]
    [StringLength(30)]
    public string UserRole { get; set; }
}

Once you had that cleaned up, you should just be able to create and fill a collection of UserRoles, like this, in your Controller:

var userRoleList = GetUserRolesList();
ViewData["userRoles"] = userRolesList;

and have these supporting functions:

private static SelectListItem[] _UserRolesList;

/// <summary>
/// Returns a static category list that is cached
/// </summary>
/// <returns></returns>
public SelectListItem[] GetUserRolesList()
{
    if (_UserRolesList == null)
    {
        var userRoles = repository.GetAllUserRoles().Select(a => new SelectListItem()
         {
             Text = a.UserRole,
             Value = a.UserRoleId.ToString()
         }).ToList();
         userRoles.Insert(0, new SelectListItem() { Value = "0", Text = "-- Please select your user role --" });

        _UserRolesList = userRoles.ToArray();
    }

    // Have to create new instances via projection
    // to avoid ModelBinding updates to affect this
    // globally
    return _UserRolesList
        .Select(d => new SelectListItem()
    {
         Value = d.Value,
         Text = d.Text
    })
     .ToArray();
}

Repository.cs

My Repository function GetAllUserRoles() for the function, above:

public class Repository
{
    Model1 db = new Model1(); // Entity Framework context

    // User Roles
    public IList<DbUserRoles> GetAllUserRoles()
    {
        return db.DbUserRoles.OrderBy(e => e.UserRoleId).ToList();
    }
}

AddNewUser.cshtml

Then do this in your View:

<table>
    <tr>
        <td>
            @Html.EditorFor(model => model.UserName,
                  htmlAttributes: new { @class = "form-control" }
                  )
        </td>
        <td>
            @Html.DropDownListFor(model => model.RoleId,
                  new SelectList( (IEnumerable<SelectListItem>)ViewData["userRoles"], "Value", "Text", model.RoleId),
                  htmlAttributes: new { @class = "form-control" }
                  )
         </td>
     </tr>
 </table>

CSS change button style after click

Try to check outline on button's focus:

button:focus {
    outline: blue auto 5px; 
}

If you have it, just set it to none.

Can an Android Toast be longer than Toast.LENGTH_LONG?

Simply use SuperToast to make an elegant toast on any situation. Make your toast colourful. Edit your font color and also it's size. Hope it will be all in one for you.

"Mixed content blocked" when running an HTTP AJAX operation in an HTTPS page

I was same problem, but for me the problem was ng build command. I was doing "ng build --prod" i have corrected it to "ng build --prod --base-href /applicationname/". and this solved my problem.

java.lang.IllegalStateException: Fragment not attached to Activity

I Found Very Simple Solution isAdded() method which is one of the fragment method to identify that this current fragment is attached to its Activity or not.

we can use this like everywhere in fragment class like:

if(isAdded())
{

// using this method, we can do whatever we want which will prevent   **java.lang.IllegalStateException: Fragment not attached to Activity** exception.

}

MySQL Foreign Key Error 1005 errno 150 primary key as foreign key

I don't have the reputation yet to up vote Steve's suggestion, but it solved my problem.

In my case, I received this error because the two table where created using different database engines--one was Innodb and the other MyISAM.

You can change the database type using : ALTER TABLE t ENGINE = MYISAM;

@see http://dev.mysql.com/doc/refman/5.1/en/storage-engine-setting.html

How do I print out the contents of a vector?

Coming out of one of the first BoostCon (now called CppCon), I and two others worked on a library to do just this. The main sticking point was needing to extend namespace std. That turned out to be a no-go for a boost library.

Unfortunately the links to the code no longer work, but you might find some interesting tidbits in the discussions (at least those that aren't talking about what to name it!)

http://boost.2283326.n4.nabble.com/explore-Library-Proposal-Container-Streaming-td2619544.html

Setting state on componentDidMount()

It is not an anti-pattern to call setState in componentDidMount. In fact, ReactJS provides an example of this in their documentation:

You should populate data with AJAX calls in the componentDidMount lifecycle method. This is so you can use setState to update your component when the data is retrieved.

Example From Doc

componentDidMount() {
    fetch("https://api.example.com/items")
      .then(res => res.json())
      .then(
        (result) => {
          this.setState({
            isLoaded: true,
            items: result.items
          });
        },
        // Note: it's important to handle errors here
        // instead of a catch() block so that we don't swallow
        // exceptions from actual bugs in components.
        (error) => {
          this.setState({
            isLoaded: true,
            error
          });
        }
      )
  }

Load jQuery with Javascript and use jQuery

There is an other way to load jQuery dynamically (source). You could also use

document.write('<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"><\/script>');

It's considered bad practice to use document.write, but for sake of completion it's good to mention it.

See Why is document.write considered a "bad practice"? for the reasons. The pro is that document.write does block your page from loading other assests, so there is no need to create a callback function.

PostgreSQL: export resulting data from SQL query to Excel/CSV

In PostgreSQL 9.4 to create to file CSV with the header in Ubuntu:

COPY (SELECT * FROM tbl) TO '/home/user/Desktop/result_sql.csv' WITH CSV HEADER;

Note: The folder must be writable.

Writing sqlplus output to a file

Make sure you have the access to the directory you are trying to spool. I tried to spool to root and it did not created the file (e.g c:\test.txt). You can check where you are spooling by issuing spool command.

Change WPF window background image in C# code

Uri resourceUri = new Uri(@"/cCleaner;component/Images/cleanerblack.png", UriKind.Relative);
            StreamResourceInfo streamInfo = Application.GetResourceStream(resourceUri);
            BitmapFrame temp = BitmapFrame.Create(streamInfo.Stream);
            var brush = new ImageBrush();
            brush.ImageSource = temp;
            frame8.Background = brush;

Scanner is skipping nextLine() after using next() or nextFoo()?

The problem is with the input.nextInt() method - it only reads the int value. So when you continue reading with input.nextLine() you receive the "\n" Enter key. So to skip this you have to add the input.nextLine(). Hope this should be clear now.

Try it like that:

System.out.print("Insert a number: ");
int number = input.nextInt();
input.nextLine(); // This line you have to add (It consumes the \n character)
System.out.print("Text1: ");
String text1 = input.nextLine();
System.out.print("Text2: ");
String text2 = input.nextLine();

How to fix apt-get: command not found on AWS EC2?

I guess you are actually using Amazon Linux AMI 2013.03.1 instead of Ubuntu Server 12.x reason why you don't have apt-get tool installed.

Git status ignore line endings / identical files / windows & linux environment / dropbox / mled

Issue related to git commands on Windows operating system:

$ git add --all

warning: LF will be replaced by CRLF in ...

The file will have its original line endings in your working directory.

Resolution:

$ git config --global core.autocrlf false     
$ git add --all 

No any warning messages come up.

WordPress: get author info from post id

I figured it out.

<?php $author_id=$post->post_author; ?>
<img src="<?php the_author_meta( 'avatar' , $author_id ); ?> " width="140" height="140" class="avatar" alt="<?php echo the_author_meta( 'display_name' , $author_id ); ?>" />
<?php the_author_meta( 'user_nicename' , $author_id ); ?> 

Initialise numpy array of unknown length

For posterity, I think this is quicker:

a = np.array([np.array(list()) for _ in y])

You might even be able to pass in a generator (i.e. [] -> ()), in which case the inner list is never fully stored in memory.


Responding to comment below:

>>> import numpy as np
>>> y = range(10)
>>> a = np.array([np.array(list) for _ in y])
>>> a
array([array(<type 'list'>, dtype=object),
       array(<type 'list'>, dtype=object),
       array(<type 'list'>, dtype=object),
       array(<type 'list'>, dtype=object),
       array(<type 'list'>, dtype=object),
       array(<type 'list'>, dtype=object),
       array(<type 'list'>, dtype=object),
       array(<type 'list'>, dtype=object),
       array(<type 'list'>, dtype=object),
       array(<type 'list'>, dtype=object)], dtype=object)

Assigning a function to a variable

When you assign a function to a variable you don't use the () but simply the name of the function.

In your case given def x(): ..., and variable silly_var you would do something like this:

silly_var = x

and then you can call the function either with

x()

or

silly_var()

Converting milliseconds to minutes and seconds with Javascript

this code will do a better job if you want to show hours, and centiseconds or miliseconds after seconds like 1:02:32.21 and if used in a cell phone the timer will show correct timing even after screen lock.

_x000D_
_x000D_
<div id="timer" style="font-family:monospace;">00:00<small>.00</small></div>_x000D_
_x000D_
<script>_x000D_
var d = new Date();_x000D_
var n = d.getTime();_x000D_
var startTime = n;_x000D_
_x000D_
var tm=0;_x000D_
function updateTimer(){_x000D_
  d = new Date();_x000D_
  n = d.getTime();_x000D_
  var currentTime = n;  _x000D_
  tm = (currentTime-startTime);_x000D_
  _x000D_
  //tm +=1; _x000D_
  // si el timer cuenta en centesimas de segundo_x000D_
  //tm = tm*10;_x000D_
  _x000D_
  var hours = Math.floor(tm / 1000 / 60 / 60);_x000D_
  var minutes = Math.floor(tm / 60000) % 60;_x000D_
  var seconds =  ((tm / 1000) % 60);_x000D_
  // saca los decimales ej 2 d{0,2}_x000D_
  var seconds = seconds.toString().match(/^-?\d+(?:\.\d{0,-1})?/)[0];_x000D_
  var miliseconds = ("00" + tm).slice(-3);_x000D_
  var centiseconds;_x000D_
_x000D_
  _x000D_
  // si el timer cuenta en centesimas de segundo_x000D_
  //tm = tm/10;_x000D_
_x000D_
_x000D_
  centiseconds = miliseconds/10;_x000D_
  centiseconds = (centiseconds).toString().match(/^-?\d+(?:\.\d{0,-1})?/)[0];_x000D_
_x000D_
  minutes = (minutes < 10 ? '0' : '') + minutes;_x000D_
  seconds = (seconds < 10 ? '0' : '') + seconds;_x000D_
  centiseconds = (centiseconds < 10 ? '0' : '') + centiseconds;_x000D_
  hours = hours + (hours > 0 ? ':' : '');_x000D_
  if (hours==0){_x000D_
    hours='';_x000D_
  }_x000D_
_x000D_
  document.getElementById("timer").innerHTML = hours + minutes + ':' + seconds + '<small>.' + centiseconds + '</small>';_x000D_
}_x000D_
_x000D_
var timerInterval = setInterval(updateTimer, 10);_x000D_
// clearInterval(timerInterval);_x000D_
</script>
_x000D_
_x000D_
_x000D_

What is the best IDE for C Development / Why use Emacs over an IDE?

Netbeans has great C and C++ support. Some people complain that it's bloated and slow, but I've been using it almost exclusively for personal projects and love it. The code assistance feature is one of the best I've seen.

You need to install postgresql-server-dev-X.Y for building a server-side extension or libpq-dev for building a client-side application

I was using a virtual environment on Ubuntu 18.04, and since I only wanted to install it as a client, I only had to do:

sudo apt install libpq-dev
pip install psycopg2

And installed without problems. Of course, you can use the binary as other answers said, but I preferred this solution since it was stated in a requirements.txt file.

Using pointer to char array, values in that array can be accessed?

Most people responding don't even seem to know what an array pointer is...

The problem is that you do pointer arithmetics with an array pointer: ptr + 1 will mean "jump 5 bytes ahead since ptr points at a 5 byte array".

Do like this instead:

#include <stdio.h>

int main()
{
  char (*ptr)[5];
  char arr[5] = {'a','b','c','d','e'};
  int i;

  ptr = &arr;
  for(i=0; i<5; i++)
  {
    printf("\nvalue: %c", (*ptr)[i]);
  }
}

Take the contents of what the array pointer points at and you get an array. So they work just like any pointer in C.

Failed to fetch URL https://dl-ssl.google.com/android/repository/addons_list-1.xml, reason: Connection to https://dl-ssl.google.com refused

After 7 long hours of searching I finally found the way!! None of the above solutions worked, only one of them pointed towards the issue!

If you are on Win7, then your Firewall blocks the SDK Manager from retrieving the addon list. You will have to add "android.bat" and "java.exe" to the trusted files and bingo! everything will start working!!

Angular - ui-router get previous state

Here is a really elegant solution from Chris Thielen ui-router-extras: $previousState

var previous = $previousState.get(); //Gets a reference to the previous state.

previous is an object that looks like: { state: fromState, params: fromParams } where fromState is the previous state and fromParams is the previous state parameters.

How to remove the character at a given index from a string in C?

This might be one of the fastest ones, if you pass the index:

void removeChar(char *str, unsigned int index) {
    char *src;
    for (src = str+index; *src != '\0'; *src = *(src+1),++src) ;
    *src = '\0';
}

How to find out which JavaScript events fired?

Looks like Firebug (Firefox add-on) has the answer:

  • open Firebug
  • right click the element in HTML tab
  • click Log Events
  • enable Console tab
  • click Persist in Console tab (otherwise Console tab will clear after the page is reloaded)
  • select Closed (manually)
  • there will be something like this in Console tab:

    ...
    mousemove clientX=1097, clientY=292
    popupshowing
    mousedown clientX=1097, clientY=292
    focus
    mouseup clientX=1097, clientY=292
    click clientX=1097, clientY=292
    mousemove clientX=1096, clientY=293
    ...
    

Source: Firebug Tip: Log Events

How do I tokenize a string in C++?

pystring is a small library which implements a bunch of Python's string functions, including the split method:

#include <string>
#include <vector>
#include "pystring.h"

std::vector<std::string> chunks;
pystring::split("this string", chunks);

// also can specify a separator
pystring::split("this-string", chunks, "-");

Change default text in input type="file"?

_x000D_
_x000D_
$(document).ready(function () {_x000D_
 $('#choose-file').change(function () {_x000D_
  var i = $(this).prev('label').clone();_x000D_
  var file = $('#choose-file')[0].files[0].name;_x000D_
  $(this).prev('label').text(file);_x000D_
 }); _x000D_
 });
_x000D_
.custom-file-upload{_x000D_
  background: #f7f7f7; _x000D_
  padding: 8px;_x000D_
  border: 1px solid #e3e3e3; _x000D_
  border-radius: 5px; _x000D_
  border: 1px solid #ccc; _x000D_
  display: inline-block;_x000D_
  padding: 6px 12px;_x000D_
  cursor: pointer;_x000D_
}
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
can you try this_x000D_
_x000D_
<label for="choose-file" class="custom-file-upload" id="choose-file-label">_x000D_
   Upload Document_x000D_
</label>_x000D_
<input name="uploadDocument" type="file" id="choose-file" _x000D_
   accept=".jpg,.jpeg,.pdf,doc,docx,application/msword,.png" style="display: none;" />
_x000D_
_x000D_
_x000D_

How do I programmatically change file permissions?

Full control over file attributes is available in Java 7, as part of the "new" New IO facility (NIO.2). For example, POSIX permissions can be set on an existing file with setPosixFilePermissions(), or atomically at file creation with methods like createFile() or newByteChannel().

You can create a set of permissions using EnumSet.of(), but the helper method PosixFilePermissions.fromString() will uses a conventional format that will be more readable to many developers. For APIs that accept a FileAttribute, you can wrap the set of permissions with with PosixFilePermissions.asFileAttribute().

Set<PosixFilePermission> ownerWritable = PosixFilePermissions.fromString("rw-r--r--");
FileAttribute<?> permissions = PosixFilePermissions.asFileAttribute(ownerWritable);
Files.createFile(path, permissions);

In earlier versions of Java, using native code of your own, or exec-ing command-line utilities are common approaches.

Get value of a merged cell of an excel from its cell address in vba

Even if it is really discouraged to use merge cells in Excel (use Center Across Selection for instance if needed), the cell that "contains" the value is the one on the top left (at least, that's a way to express it).

Hence, you can get the value of merged cells in range B4:B11 in several ways:

  • Range("B4").Value
  • Range("B4:B11").Cells(1).Value
  • Range("B4:B11").Cells(1,1).Value

You can also note that all the other cells have no value in them. While debugging, you can see that the value is empty.

Also note that Range("B4:B11").Value won't work (raises an execution error number 13 if you try to Debug.Print it) because it returns an array.

Evaluate expression given as a string

Nowadays you can also use lazy_eval function from lazyeval package.

> lazyeval::lazy_eval("5+5")
[1] 10

How can I pass a parameter to a setTimeout() callback?

@Jiri Vetyska thanks for the post, but there is something wrong in your example. I needed to pass the target which is hovered out (this) to a timed out function and I tried your approach. Tested in IE9 - does not work. I also made some research and it appears that as pointed here the third parameter is the script language being used. No mention about additional parameters.

So, I followed @meder's answer and solved my issue with this code:

$('.targetItemClass').hover(ItemHoverIn, ItemHoverOut);

function ItemHoverIn() {
 //some code here
}

function ItemHoverOut() {
    var THIS = this;
    setTimeout(
        function () { ItemHoverOut_timeout(THIS); },
        100
    );
}
function ItemHoverOut_timeout(target) {
    //do something with target which is hovered out
}

Hope, this is usefull for someone else.

Run a string as a command within a Bash script

don't put your commands in variables, just run it

matchdir="/home/joao/robocup/runner_workdir/matches/testmatch/"
PWD=$(pwd)
teamAComm="$PWD/a.sh"
teamBComm="$PWD/b.sh"
include="$PWD/server_official.conf"
serverbin='/usr/local/bin/rcssserver'    
cd $matchdir
$serverbin include=$include server::team_l_start = ${teamAComm} server::team_r_start=${teamBComm} CSVSaver::save='true' CSVSaver::filename = 'out.csv'

How to add an Access-Control-Allow-Origin header

Check this link.. It will definitely solve your problem.. There are plenty of solutions to make cross domain GET Ajax calls BUT POST REQUEST FOR CROSS DOMAIN IS SOLVED HERE. It took me 3 days to figure it out.

http://blogs.msdn.com/b/carlosfigueira/archive/2012/02/20/implementing-cors-support-in-asp-net-web-apis.aspx

Subtract two dates in Java

Date d1 = new SimpleDateFormat("yyyy-M-dd").parse((String) request.
            getParameter(date1));
Date d2 = new SimpleDateFormat("yyyy-M-dd").parse((String) request.
            getParameter(date2));

long diff = d2.getTime() - d1.getTime();

System.out.println("Difference between  " + d1 + " and "+ d2+" is "
        + (diff / (1000 * 60 * 60 * 24)) + " days.");

Where is git.exe located?

I found it at

C:\Users\~\AppData\Local\GitHub\PortableGit_<some_identifier>\mingw32\libexec\git-core\

Creating instance list of different objects

I see that all of the answers suggest using a list filled with Object classes and then explicitly casting the desired class, and I personally don't like that kind of approach.

What works better for me is to create an interface which contains methods for retrieving or storing data from/to certain classes I want to put in a list. Have those classes implement that new interface, add the methods from the interface into them and then you can fill the list with interface objects - List<NewInterface> newInterfaceList = new ArrayList<>() thus being able to extract the desired data from the objects in a list without having the need to explicitly cast anything.

You can also put a comparator in the interface if you need to sort the list.

How can I run an external command asynchronously from Python?

I have the same problem trying to connect to an 3270 terminal using the s3270 scripting software in Python. Now I'm solving the problem with an subclass of Process that I found here:

http://code.activestate.com/recipes/440554/

And here is the sample taken from file:

def recv_some(p, t=.1, e=1, tr=5, stderr=0):
    if tr < 1:
        tr = 1
    x = time.time()+t
    y = []
    r = ''
    pr = p.recv
    if stderr:
        pr = p.recv_err
    while time.time() < x or r:
        r = pr()
        if r is None:
            if e:
                raise Exception(message)
            else:
                break
        elif r:
            y.append(r)
        else:
            time.sleep(max((x-time.time())/tr, 0))
    return ''.join(y)

def send_all(p, data):
    while len(data):
        sent = p.send(data)
        if sent is None:
            raise Exception(message)
        data = buffer(data, sent)

if __name__ == '__main__':
    if sys.platform == 'win32':
        shell, commands, tail = ('cmd', ('dir /w', 'echo HELLO WORLD'), '\r\n')
    else:
        shell, commands, tail = ('sh', ('ls', 'echo HELLO WORLD'), '\n')

    a = Popen(shell, stdin=PIPE, stdout=PIPE)
    print recv_some(a),
    for cmd in commands:
        send_all(a, cmd + tail)
        print recv_some(a),
    send_all(a, 'exit' + tail)
    print recv_some(a, e=0)
    a.wait()

How do I view events fired on an element in Chrome DevTools?

  • Hit F12 to open Dev Tools
  • Click the Sources tab
  • On right-hand side, scroll down to "Event Listener Breakpoints", and expand tree
  • Click on the events you want to listen for.
  • Interact with the target element, if they fire you will get a break point in the debugger

Similarly, you can right click on the target element -> select "inspect element" Scroll down on the right side of the dev frame, at the bottom is 'event listeners'. Expand the tree to see what events are attached to the element. Not sure if this works for events that are handled through bubbling (I'm guessing not)

Get first and last day of month using threeten, LocalDate

YearMonth

For completeness, and more elegant in my opinion, see this use of YearMonth class.

YearMonth month = YearMonth.from(date);
LocalDate start = month.atDay(1);
LocalDate end   = month.atEndOfMonth();

For the first & last day of the current month, this becomes:

LocalDate start = YearMonth.now().atDay(1);
LocalDate end   = YearMonth.now().atEndOfMonth();

Exception thrown in catch and finally clause

This is what Wikipedia says about finally clause:

More common is a related clause (finally, or ensure) that is executed whether an exception occurred or not, typically to release resources acquired within the body of the exception-handling block.

Let's dissect your program.

try {
    System.out.print(1);
    q();
}

So, 1 will be output into the screen, then q() is called. In q(), an exception is thrown. The exception is then caught by Exception y but it does nothing. A finally clause is then executed (it has to), so, 3 will be printed to screen. Because (in method q() there's an exception thrown in the finally clause, also q() method passes the exception to the parent stack (by the throws Exception in the method declaration) new Exception() will be thrown and caught by catch ( Exception i ), MyExc2 exception will be thrown (for now add it to the exception stack), but a finally in the main block will be executed first.

So in,

catch ( Exception i ) {
    throw( new MyExc2() );
} 
finally {
    System.out.print(2);
    throw( new MyExc1() );
}

A finally clause is called...(remember, we've just caught Exception i and thrown MyExc2) in essence, 2 is printed on screen...and after the 2 is printed on screen, a MyExc1 exception is thrown. MyExc1 is handled by the public static void main(...) method.

Output:

"132Exception in thread main MyExc1"

Lecturer is correct! :-)

In essence, if you have a finally in a try/catch clause, a finally will be executed (after catching the exception before throwing the caught exception out)

SQL Server stored procedure Nullable parameter

It looks like you're passing in Null for every argument except for PropertyValueID and DropDownOptionID, right? I don't think any of your IF statements will fire if only these two values are not-null. In short, I think you have a logic error.

Other than that, I would suggest two things...

First, instead of testing for NULL, use this kind syntax on your if statements (it's safer)...

    ELSE IF ISNULL(@UnitValue, 0) != 0 AND ISNULL(@UnitOfMeasureID, 0) = 0

Second, add a meaningful PRINT statement before each UPDATE. That way, when you run the sproc in MSSQL, you can look at the messages and see how far it's actually getting.

Convert Date format into DD/MMM/YYYY format in SQL Server

Try this :

select replace ( convert(varchar,getdate(),106),' ','/')

Java and unlimited decimal places?

I believe that you are looking for the java.lang.BigDecimal class.

What is going wrong when Visual Studio tells me "xcopy exited with code 4"

I received the 'exited with code 4' error when the xcopy command tried to overwrite a readonly file. I managed to solve this problem by adding /R to the xcopy command. The /R indicates read only files should be overwritten

old command:

XCOPY /E /Y "$(ProjectDir)source file" "destination"

new command

XCOPY /E /Y /R "$(ProjectDir)source file" "destination"

How to download image from url

Try this it worked for me

Write this in your Controller

public class DemoController: Controller

        public async Task<FileStreamResult> GetLogoImage(string logoimage)
        {
            string str = "" ;
            var filePath = Server.MapPath("~/App_Data/" + SubfolderName);//If subfolder exist otherwise leave.
            // DirectoryInfo dir = new DirectoryInfo(filePath);
            string[] filePaths = Directory.GetFiles(@filePath, "*.*");
            foreach (var fileTemp in filePaths)
            {
                  str= fileTemp.ToString();
            }
                return File(new MemoryStream(System.IO.File.ReadAllBytes(str)), System.Web.MimeMapping.GetMimeMapping(str), Path.GetFileName(str));
        }

Here is my view

<div><a href="/DemoController/GetLogoImage?Type=Logo" target="_blank">Download Logo</a></div>

matplotlib colorbar for scatter

If you're looking to scatter by two variables and color by the third, Altair can be a great choice.

Creating the dataset

import matplotlib.pyplot as plt
import numpy as np
import pandas as pd

df = pd.DataFrame(40*np.random.randn(10, 3), columns=['A', 'B','C'])

Altair plot

from altair import *
Chart(df).mark_circle().encode(x='A',y='B', color='C').configure_cell(width=200, height=150)

Plot

enter image description here

SQL LEFT-JOIN on 2 fields for MySQL

select a.ip, a.os, a.hostname, a.port, a.protocol,
       b.state
from a
left join b on a.ip = b.ip 
           and a.port = b.port

How to POST the data from a modal form of Bootstrap?

You CAN include a modal within a form. In the Bootstrap documentation it recommends the modal to be a "top level" element, but it still works within a form.

You create a form, and then the modal "save" button will be a button of type="submit" to submit the form from within the modal.

<form asp-action="AddUsersToRole" method="POST" class="mb-3">

    @await Html.PartialAsync("~/Views/Users/_SelectList.cshtml", Model.Users)

    <div class="modal fade" id="role-select-modal" tabindex="-1" role="dialog" aria-labelledby="role-select-modal" aria-hidden="true">
        <div class="modal-dialog" role="document">
            <div class="modal-content">
                <div class="modal-header">
                    <h5 class="modal-title" id="exampleModalLabel">Select a Role</h5>
                </div>
                <div class="modal-body">
                    ...
                </div>
                <div class="modal-footer">
                    <button type="submit" class="btn btn-primary">Add Users to Role</button>
                    <button type="button" class="btn btn-secondary" data-dismiss="modal">Cancel</button>
                </div>
            </div>
        </div>
    </div>

</form>

You can post (or GET) your form data to any URL. By default it is the serving page URL, but you can change it by setting the form action. You do not have to use ajax.

Mozilla documentation on form action

TypeError: You provided an invalid object where a stream was expected. You can provide an Observable, Promise, Array, or Iterable

You will get the following error message too when you provide undefined or so to an operator which expects an Observable, eg. takeUntil.

TypeError: You provided an invalid object where a stream was expected. You can provide an Observable, Promise, Array, or Iterable 

relative path to CSS file

Background

Absolute: The browser will always interpret / as the root of the hostname. For example, if my site was http://google.com/ and I specified /css/images.css then it would search for that at http://google.com/css/images.css. If your project root was actually at /myproject/ it would not find the css file. Therefore, you need to determine where your project folder root is relative to the hostname, and specify that in your href notation.

Relative: If you want to reference something you know is in the same path on the url - that is, if it is in the same folder, for example http://mysite.com/myUrlPath/index.html and http://mysite.com/myUrlPath/css/style.css, and you know that it will always be this way, you can go against convention and specify a relative path by not putting a leading / in front of your path, for example, css/style.css.

Filesystem Notations: Additionally, you can use standard filesystem notations like ... If you do http://google.com/images/../images/../images/myImage.png it would be the same as http://google.com/images/myImage.png. If you want to reference something that is one directory up from your file, use ../myFile.css.


Your Specific Case

In your case, you have two options:

  • <link rel="stylesheet" type="text/css" href="/ServletApp/css/styles.css"/>
  • <link rel="stylesheet" type="text/css" href="css/styles.css"/>

The first will be more concrete and compatible if you move things around, however if you are planning to keep the file in the same location, and you are planning to remove the /ServletApp/ part of the URL, then the second solution is better.

Twitter Bootstrap hide css class and jQuery

If an element has bootstrap's "hide" class and you want to display it with some sliding effect such as .slideDown(), you can cheat bootstrap like:

$('#hiddenElement').hide().removeClass('hide').slideDown('fast')

How to remove foreign key constraint in sql server?

Drop all the foreign keys of a table:

USE [Database_Name]
DECLARE @FOREIGN_KEY_NAME VARCHAR(100)

DECLARE FOREIGN_KEY_CURSOR CURSOR FOR
SELECT name FOREIGN_KEY_NAME FROM sys.foreign_keys WHERE parent_object_id = (SELECT object_id FROM sys.objects WHERE name = 'Table_Name' AND TYPE = 'U')

OPEN FOREIGN_KEY_CURSOR
----------------------------------------------------------
FETCH NEXT FROM FOREIGN_KEY_CURSOR INTO @FOREIGN_KEY_NAME
WHILE @@FETCH_STATUS = 0
    BEGIN
       DECLARE @DROP_COMMAND NVARCHAR(150) = 'ALTER TABLE Table_Name DROP CONSTRAINT' + ' ' + @FOREIGN_KEY_NAME

       EXECUTE Sp_executesql @DROP_COMMAND

       FETCH NEXT FROM FOREIGN_KEY_CURSOR INTO @FOREIGN_KEY_NAME

    END
-----------------------------------------------------------------------------------------------------------------
CLOSE FOREIGN_KEY_CURSOR
DEALLOCATE FOREIGN_KEY_CURSOR

Visual Studio "Could not copy" .... during build

Delete any .cache files under your Debug or Release folders inside the Bin folder.

Java reverse an int value without using array

 public static int reverseInt(int i) {
    int reservedInt = 0;

    try{
        String s = String.valueOf(i);
        String reversed = reverseWithStringBuilder(s);
        reservedInt = Integer.parseInt(reversed);

    }catch (NumberFormatException e){
        System.out.println("exception caught was " + e.getMessage());
    }
    return reservedInt;
}

public static String reverseWithStringBuilder(String str) {
    System.out.println(str);
    StringBuilder sb = new StringBuilder(str);
    StringBuilder reversed = sb.reverse();
    return reversed.toString();
}

HTTP Error 500.30 - ANCM In-Process Start Failure

I had a similar issue when attempting to switch to from OutOfProcess hosting to InProcess hosting on a .Net Core project which I had recently upgraded from 2.0 to 3.0.

With no real helpful error to go on and after spending days trying to resolve this, I eventually found a fix for my case which I thought I'd share in case it is helpful to anyone else struggling with this.

For me, it was caused by a few Microsoft.AspNetCore packages.

After removing all of the referenced Microsoft.AspNetCore packages that had version less than 3.0.0 (there was no upgrade available >= 3.0.0 for these) this error no longer occurred.

These were the packages I removed;

<PackageReference Include="Microsoft.AspNetCore" Version="2.2.0" />
<PackageReference Include="Microsoft.AspNetCore.App" Version="2.2.8" />
<PackageReference Include="Microsoft.AspNetCore.Server.IISIntegration" Version="2.2.1" />
<PackageReference Include="Microsoft.AspNetCore.StaticFiles" Version="2.2.0" />

All other Microsoft.AspNetCore packages with version greater than or equal to 3.0.0 worked fine.

Save array in mysql database

Use the PHP function serialize() to convert arrays to strings. These strings can easily be stored in MySQL database. Using unserialize() they can be converted to arrays again if needed.

SQL: How to perform string does not equal

Try the following query

select * from table
where NOT (tester = 'username')

Must JDBC Resultsets and Statements be closed separately although the Connection is closed afterwards?

Java 1.7 makes our lives much easier thanks to the try-with-resources statement.

try (Connection connection = dataSource.getConnection();
    Statement statement = connection.createStatement()) {
    try (ResultSet resultSet = statement.executeQuery("some query")) {
        // Do stuff with the result set.
    }
    try (ResultSet resultSet = statement.executeQuery("some query")) {
        // Do more stuff with the second result set.
    }
}

This syntax is quite brief and elegant. And connection will indeed be closed even when the statement couldn't be created.

ASP.NET Temporary files cleanup

Just an update on more current OS's (Vista, Win7, etc.) - the temp file path has changed may be different based on several variables. The items below are not definitive, however, they are a few I have encountered:

"temp" environment variable setting - then it would be:

%temp%\Temporary ASP.NET Files

Permissions and what application/process (VS, IIS, IIS Express) is running the .Net compiler. Accessing the C:\WINDOWS\Microsoft.NET\Framework folders requires elevated permissions and if you are not developing under an account with sufficient permissions then this folder might be used:

c:\Users\[youruserid]\AppData\Local\Temp\Temporary ASP.NET Files

There are also cases where the temp folder can be set via config for a machine or site specific using this:

<compilation tempDirectory="d:\MyTempPlace" />

I even have a funky setup at work where we don't run Admin by default, plus the IT guys have login scripts that set %temp% and I get temp files in 3 different locations depending on what is compiling things! And I'm still not certain about how these paths get picked....sigh.

Still, dthrasher is correct, you can just delete these and VS and IIS will just recompile them as needed.

How to tell if a string is not defined in a Bash shell script

https://stackoverflow.com/a/9824943/14731 contains a better answer (one that is more readable and works with set -o nounset enabled). It works roughly like this:

if [ -n "${VAR-}" ]; then
    echo "VAR is set and is not empty"
elif [ "${VAR+DEFINED_BUT_EMPTY}" = "DEFINED_BUT_EMPTY" ]; then
    echo "VAR is set, but empty"
else
    echo "VAR is not set"
fi

Python 3 Float Decimal Points/Precision

In a word, you can't.

3.65 cannot be represented exactly as a float. The number that you're getting is the nearest number to 3.65 that has an exact float representation.

The difference between (older?) Python 2 and 3 is purely due to the default formatting.

I am seeing the following both in Python 2.7.3 and 3.3.0:

In [1]: 3.65
Out[1]: 3.65

In [2]: '%.20f' % 3.65
Out[2]: '3.64999999999999991118'

For an exact decimal datatype, see decimal.Decimal.

How to convert milliseconds to "hh:mm:ss" format?

Java 9

    Duration timeLeft = Duration.ofMillis(3600000);
    String hhmmss = String.format("%02d:%02d:%02d", 
            timeLeft.toHours(), timeLeft.toMinutesPart(), timeLeft.toSecondsPart());
    System.out.println(hhmmss);

This prints:

01:00:00

You are doing right in letting library methods do the conversions involved for you. java.time, the modern Java date and time API, or more precisely, its Duration class does it more elegantly and in a less error-prone way than TimeUnit.

The toMinutesPart and toSecondsPart methods I used were introduced in Java 9.

Java 6, 7 and 8

    long hours = timeLeft.toHours();
    timeLeft = timeLeft.minusHours(hours);
    long minutes = timeLeft.toMinutes();
    timeLeft = timeLeft.minusMinutes(minutes);
    long seconds = timeLeft.toSeconds();
    String hhmmss = String.format("%02d:%02d:%02d", hours, minutes, seconds);
    System.out.println(hhmmss);

The output is the same as above.

Question: How can that work in Java 6 and 7?

  • In Java 8 and later and on newer Android devices (from API level 26, I’m told) java.time comes built-in.
  • In Java 6 and 7 get the ThreeTen Backport, the backport of the modern classes (ThreeTen for JSR 310; see the links at the bottom).
  • On (older) Android use the Android edition of ThreeTen Backport. It’s called ThreeTenABP. And make sure you import the date and time classes from org.threeten.bp with subpackages.

Links

Loading cross-domain endpoint with AJAX

To get the data form external site by passing using a local proxy as suggested by jherax you can create a php page that fetches the content for you from respective external url and than send a get request to that php page.

var req = new XMLHttpRequest();
req.open('GET', 'http://localhost/get_url_content.php',false);
if(req.status == 200) {
   alert(req.responseText);
}

as a php proxy you can use https://github.com/cowboy/php-simple-proxy

How to debug a bash script?

Use eclipse with the plugins shelled & basheclipse.

https://sourceforge.net/projects/shelled/?source=directory https://sourceforge.net/projects/basheclipse/?source=directory

For shelled: Download the zip and import it into eclipse via help -> install new software : local archive For basheclipse: Copy the jars into dropins directory of eclipse

Follow the steps provides https://sourceforge.net/projects/basheclipse/files/?source=navbar

enter image description here

I wrote a tutorial with many screenshots at http://dietrichschroff.blogspot.de/2017/07/bash-enabling-eclipse-for-bash.html

How to call getClass() from a static method in Java?

Try it

Thread.currentThread().getStackTrace()[1].getClassName()

Or

Thread.currentThread().getStackTrace()[2].getClassName()

Docker can't connect to docker daemon

you can run the daemon with the following command:

sudo nohup docker daemon -H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock &

The script leaves the daemon running in the background, and with the Docker ready you can test that it is accepting commands.

sudo docker info

for more information check this out: https://www.upcloud.com/support/how-to-configure-docker-swarm/

How do I remove the last comma from a string using PHP?

Try:

$string = "'name', 'name2', 'name3',";
$string = rtrim($string,',');

Replace first occurrence of string in Python

string replace() function perfectly solves this problem:

string.replace(s, old, new[, maxreplace])

Return a copy of string s with all occurrences of substring old replaced by new. If the optional argument maxreplace is given, the first maxreplace occurrences are replaced.

>>> u'longlongTESTstringTEST'.replace('TEST', '?', 1)
u'longlong?stringTEST'

Postgresql column reference "id" is ambiguous

SELECT (vg.id, name) FROM v_groups vg 
INNER JOIN people2v_groups p2vg ON vg.id = p2vg.v_group_id
WHERE p2vg.people_id = 0;

Loop through JSON object List

Here it is:

success: 
    function(data) {
        $.each(data, function(i, item){
            alert("Mine is " + i + "|" + item.title + "|" + item.key);
        });
    }

Sample JSON text:

{"title": "camp crowhouse", 
"key": "agtnZW90YWdkZXYyMXIKCxIEUG9zdBgUDA"}

How to know a Pod's own IP address from inside a container in the Pod?

You could use

kubectl describe pod `hostname` | grep IP | sed -E 's/IP:[[:space:]]+//'

which is based on what @mibbit suggested.

This takes the following facts into account:

Go / golang time.Now().UnixNano() convert to milliseconds?

Keep it simple.

func NowAsUnixMilli() int64 {
    return time.Now().UnixNano() / 1e6
}

Disable scrolling when touch moving certain element

Set the touch-action CSS property to none, which works even with passive event listeners:

touch-action: none;

Applying this property to an element will not trigger the default (scroll) behavior when the event is originating from that element.

Vue.JS: How to call function after page loaded?

Vue watch() life-cycle hook, can be used

html

<div id="demo">{{ fullName }}</div>

js

var vm = new Vue({
  el: '#demo',
  data: {
    firstName: 'Foo',
    lastName: 'Bar',
    fullName: 'Foo Bar'
  },
  watch: {
    firstName: function (val) {
      this.fullName = val + ' ' + this.lastName
    },
    lastName: function (val) {
      this.fullName = this.firstName + ' ' + val
    }
  }
})

*.h or *.hpp for your class definitions

Fortunately, it is simple.

You should use the .hpp extension if you're working with C++ and you should use .h for C or mixing C and C++.

Laravel Eloquent LEFT JOIN WHERE NULL

I would be using laravel whereDoesntHave to achieve this.

Customer::whereDoesntHave('orders')->get();

How to change dot size in gnuplot

The pointsize command scales the size of points, but does not affect the size of dots.

In other words, plot ... with points ps 2 will generate points of twice the normal size, but for plot ... with dots ps 2 the "ps 2" part is ignored.

You could use circular points (pt 7), which look just like dots.

Angular 2 execute script after template render

I've used this method (reported here )

export class AppComponent {

  constructor() {
    if(document.getElementById("testScript"))
      document.getElementById("testScript").remove();
    var testScript = document.createElement("script");
    testScript.setAttribute("id", "testScript");
    testScript.setAttribute("src", "assets/js/test.js");
    document.body.appendChild(testScript);
  }
}

it worked for me since I wanted to execute a javascript file AFTER THE COMPONENT RENDERED.

How to control font sizes in pgf/tikz graphics in latex?

\begin{tikzpicture}
    \tikzstyle{every node}=[font=\fontsize{30}{30}\selectfont]
\end{tikzpicture}

C#: Limit the length of a string?

string shortFoo = foo.Length > 5 ? foo.Substring(0, 5) : foo;

Note that you can't just use foo.Substring(0, 5) by itself because it will throw an error when foo is less than 5 characters.

How to upload a project to Github

Probably the most useful thing you could do is to peruse the online book [http://git-scm.com/book/en/]. It's really a pretty decent read and gives you the conceptual context with which to execute things properly.

Is there a way to follow redirects with command line cURL?

As said, to follow redirects you can use the flag -L or --location:

curl -L http://www.example.com

But, if you want limit the number of redirects, add the parameter --max-redirs

--max-redirs <num>

Set maximum number of redirection-followings allowed. If -L, --location is used, this option can be used to prevent curl from following redirections "in absurdum". By default, the limit is set to 50 redirections. Set this option to -1 to make it limitless. If this option is used several times, the last one will be used.

No Such Element Exception?

It looks like you are calling next even if the scanner no longer has a next element to provide... throwing the exception.

while(!file.next().equals(treasure)){
        file.next();
        }

Should be something like

boolean foundTreasure = false;

while(file.hasNext()){
     if(file.next().equals(treasure)){
          foundTreasure = true;
          break; // found treasure, if you need to use it, assign to variable beforehand
     }
}
    // out here, either we never found treasure at all, or the last element we looked as was treasure... act accordingly

WCF Error "This could be due to the fact that the server certificate is not configured properly with HTTP.SYS in the HTTPS case"

Had this issue with a true HTTPS binding and the same exception with "This could be due to the fact that the server certificate is not configured properly with HTTP.SYS in the HTTPS case...". After double checking everything in code and config, it seems like the error message is not so misleading as the inner exceptions, so after a quick check we've found out that the port 443 was hooked by skype (on the dev server). I recommend you take a look at what holding up the request (Fiddler could help here) and make sure you can reach the service front (view the .svc in your browser) and its metadata.

Good luck.

Convert seconds value to hours minutes seconds?

DateUtils.formatElapsedTime(long), formats an elapsed time in the form "MM:SS" or "H:MM:SS" . It returns the String you are looking for. You can find the documentation here

OpenJDK availability for Windows OS

Only OpenJDK 7. OpenJDK6 is basically the same code base as SUN's version, that's why it redirects you to the official Oracle site.

How can I see normal print output created during pytest run?

The -s switch disables per-test capturing (only if a test fails).

How to access List elements

Learn python the hard way ex 34

try this

animals = ['bear' , 'python' , 'peacock', 'kangaroo' , 'whale' , 'platypus']

# print "The first (1st) animal is at 0 and is a bear." 

for i in range(len(animals)):
    print "The %d animal is at %d and is a %s" % (i+1 ,i, animals[i])

# "The animal at 0 is the 1st animal and is a bear."

for i in range(len(animals)):
    print "The animal at %d is the %d and is a %s " % (i, i+1, animals[i])

Visual Studio 2017 error: Unable to start program, An operation is not legal in the current state

I just closed all open chrome instances, stopped my project and then start it again. that fixed the problem for me.

React JS Error: is not defined react/jsx-no-undef

you should do import Map from './Map' React is just telling you it doesn't know where variable you are importing is.

Why is setState in reactjs Async instead of Sync?

setState is asynchronous. You can see in this documentation by Reactjs

React intentionally “waits” until all components call setState() in their event handlers before starting to re-render. This boosts performance by avoiding unnecessary re-renders.

However, you might still be wondering why React doesn’t just update this.state immediately without re-rendering.

The reason is this would break the consistency between props and state, causing issues that are very hard to debug.

You can still perform functions if it is dependent on the change of the state value:

Option 1: Using callback function with setState

this.setState({
   value: newValue
},()=>{
   // It is an callback function.
   // Here you can access the update value
   console.log(this.state.value)
})

Option 2: using componentDidUpdate This function will be called whenever the state of that particular class changes.

componentDidUpdate(prevProps, prevState){
    //Here you can check if value of your desired variable is same or not.
    if(this.state.value !== prevState.value){
        // this part will execute if your desired variable updates
    }
}

How to get 30 days prior to current date?

Here's an ugly solution for you:

var date = new Date(new Date().setDate(new Date().getDate() - 30));

Scroll to the top of the page after render in react.js

You could use something like this. ReactDom is for react.14. Just React otherwise.

    componentDidUpdate = () => { ReactDom.findDOMNode(this).scrollIntoView(); }

Update 5/11/2019 for React 16+

_x000D_
_x000D_
  constructor(props) {_x000D_
    super(props)_x000D_
    this.childDiv = React.createRef()_x000D_
  }_x000D_
_x000D_
  componentDidMount = () => this.handleScroll()_x000D_
_x000D_
  componentDidUpdate = () => this.handleScroll()_x000D_
_x000D_
  handleScroll = () => {_x000D_
    const { index, selected } = this.props_x000D_
    if (index === selected) {_x000D_
      setTimeout(() => {_x000D_
        this.childDiv.current.scrollIntoView({ behavior: 'smooth' })_x000D_
      }, 500)_x000D_
    }_x000D_
  }
_x000D_
_x000D_
_x000D_

How to add more than one machine to the trusted hosts list using winrm

I prefer to work with the PSDrive WSMan:\.

Get TrustedHosts

Get-Item WSMan:\localhost\Client\TrustedHosts

Set TrustedHosts

provide a single, comma-separated, string of computer names

Set-Item WSMan:\localhost\Client\TrustedHosts -Value 'machineA,machineB'

or (dangerous) a wild-card

Set-Item WSMan:\localhost\Client\TrustedHosts -Value '*'

to append to the list, the -Concatenate parameter can be used

Set-Item WSMan:\localhost\Client\TrustedHosts -Value 'machineC' -Concatenate

Difference between VARCHAR2(10 CHAR) and NVARCHAR2(10)

  • The NVARCHAR2 stores variable-length character data. When you create a table with the NVARCHAR2 column, the maximum size is always in character length semantics, which is also the default and only length semantics for the NVARCHAR2 data type.

    The NVARCHAR2data type uses AL16UTF16character set which encodes Unicode data in the UTF-16 encoding. The AL16UTF16 use 2 bytes to store a character. In addition, the maximum byte length of an NVARCHAR2 depends on the configured national character set.

  • VARCHAR2 The maximum size of VARCHAR2 can be in either bytes or characters. Its column only can store characters in the default character set while the NVARCHAR2 can store virtually any characters. A single character may require up to 4 bytes.

By defining the field as:

  • VARCHAR2(10 CHAR) you tell Oracle it can use enough space to store 10 characters, no matter how many bytes it takes to store each one. A single character may require up to 4 bytes.
  • NVARCHAR2(10) you tell Oracle it can store 10 characters with 2 bytes per character

In Summary:

  • VARCHAR2(10 CHAR) can store maximum of 10 characters and maximum of 40 bytes (depends on the configured national character set).

  • NVARCHAR2(10) can store maximum of 10 characters and maximum of 20 bytes (depends on the configured national character set).

Note: Character set can be UTF-8, UTF-16,....

Please have a look at this tutorial for more detail.

Have a good day!

Using strtok with a std::string

I suppose the language is C, or C++...

strtok, IIRC, replace separators with \0. That's what it cannot use a const string. To workaround that "quickly", if the string isn't huge, you can just strdup() it. Which is wise if you need to keep the string unaltered (what the const suggest...).

On the other hand, you might want to use another tokenizer, perhaps hand rolled, less violent on the given argument.

When should we use mutex and when should we use semaphore

A mutex is a mutual exclusion object, similar to a semaphore but that only allows one locker at a time and whose ownership restrictions may be more stringent than a semaphore.

It can be thought of as equivalent to a normal counting semaphore (with a count of one) and the requirement that it can only be released by the same thread that locked it(a).

A semaphore, on the other hand, has an arbitrary count and can be locked by that many lockers concurrently. And it may not have a requirement that it be released by the same thread that claimed it (but, if not, you have to carefully track who currently has responsibility for it, much like allocated memory).

So, if you have a number of instances of a resource (say three tape drives), you could use a semaphore with a count of 3. Note that this doesn't tell you which of those tape drives you have, just that you have a certain number.

Also with semaphores, it's possible for a single locker to lock multiple instances of a resource, such as for a tape-to-tape copy. If you have one resource (say a memory location that you don't want to corrupt), a mutex is more suitable.

Equivalent operations are:

Counting semaphore          Mutual exclusion semaphore
--------------------------  --------------------------
  Claim/decrease (P)                  Lock
  Release/increase (V)                Unlock

Aside: in case you've ever wondered at the bizarre letters used for claiming and releasing semaphores, it's because the inventor was Dutch. Probeer te verlagen means to try and decrease while verhogen means to increase.


(a) ... or it can be thought of as something totally distinct from a semaphore, which may be safer given their almost-always-different uses.

Use SQL Server Management Studio to connect remotely to an SQL Server Express instance hosted on an Azure Virtual Machine

I too struggled with something similar. My guess is your actual problem is connecting to a SQL Express instance running on a different machine. The steps to do this can be summarized as follows:

  1. Ensure SQL Express is configured for SQL Authentication as well as Windows Authentication (the default). You do this via SQL Server Management Studio (SSMS) Server Properties/Security
  2. In SSMS create a new login called "sqlUser", say, with a suitable password, "sql", say. Ensure this new login is set for SQL Authentication, not Windows Authentication. SSMS Server Security/Logins/Properties/General. Also ensure "Enforce password policy" is unchecked
  3. Under Properties/Server Roles ensure this new user has the "sysadmin" role
  4. In SQL Server Configuration Manager SSCM (search for SQLServerManagerxx.msc file in Windows\SysWOW64 if you can't find SSCM) under SQL Server Network Configuration/Protocols for SQLExpress make sure TCP/IP is enabled. You can disable Named Pipes if you want
  5. Right-click protocol TCP/IP and on the IPAddresses tab, ensure every one of the IP addresses is set to Enabled Yes, and TCP Port 1433 (this is the default port for SQL Server)
  6. In Windows Firewall (WF.msc) create two new Inbound Rules - one for SQL Server and another for SQL Browser Service. For SQL Server you need to open TCP Port 1433 (if you are using the default port for SQL Server) and very importantly for the SQL Browser Service you need to open UDP Port 1434. Name these two rules suitably in your firewall
  7. Stop and restart the SQL Server Service using either SSCM or the Services.msc snap-in
  8. In the Services.msc snap-in make sure SQL Browser Service Startup Type is Automatic and then start this service

At this point you should be able to connect remotely, using SQL Authentication, user "sqlUser" password "sql" to the SQL Express instance configured as above. A final tip and easy way to check this out is to create an empty text file with the .UDL extension, say "Test.UDL" on your desktop. Double-clicking to edit this file invokes the Microsoft Data Link Properties dialog with which you can quickly test your remote SQL connection

How to access form methods and controls from a class in C#?

You need access to the object.... you can't simply ask the form class....

eg...

you would of done some thing like

Form1.txtLog.Text = "blah"

instead of

Form1 blah = new Form1();
blah.txtLog.Text = "hello"

How to center buttons in Twitter Bootstrap 3?

According to the Twitter Bootstrap documentation: http://getbootstrap.com/css/#helper-classes-center

<!-- Button -->
<div class="form-group">
   <label class="col-md-4 control-label" for="singlebutton"></label>
   <div class="col-md-4 center-block">
      <button id="singlebutton" name="singlebutton" class="btn btn-primary center-block">
          Next Step!
       </button>
   </div>  
</div>

All the class center-block does is to tell the element to have a margin of 0 auto, the auto being the left/right margins. However, unless the class text-center or css text-align:center; is set on the parent, the element does not know the point to work out this auto calculation from so will not center itself as anticipated.

See an example of the code above here: https://jsfiddle.net/Seany84/2j9pxt1z/

WebSockets protocol vs HTTP

The other answers do not seem to touch on a key aspect here, and that is you make no mention of requiring supporting a web browser as a client. Most of the limitations of plain HTTP above are assuming you would be working with browser/ JS implementations.

The HTTP protocol is fully capable of full-duplex communication; it is legal to have a client perform a POST with a chunked encoding transfer, and a server to return a response with a chunked-encoding body. This would remove the header overhead to just at init time.

So if all you're looking for is full-duplex, control both client and server, and are not interested in extra framing/features of WebSockets, then I would argue that HTTP is a simpler approach with lower latency/CPU (although the latency would really only differ in microseconds or less for either).

Using find command in bash script

Welcome to bash. It's an old, dark and mysterious thing, capable of great magic. :-)

The option you're asking about is for the find command though, not for bash. From your command line, you can man find to see the options.

The one you're looking for is -o for "or":

  list="$(find /home/user/Desktop -name '*.bmp' -o -name '*.txt')"

That said ... Don't do this. Storage like this may work for simple filenames, but as soon as you have to deal with special characters, like spaces and newlines, all bets are off. See ParsingLs for details.

$ touch 'one.txt' 'two three.txt' 'foo.bmp'
$ list="$(find . -name \*.txt -o -name \*.bmp -type f)"
$ for file in $list; do if [ ! -f "$file" ]; then echo "MISSING: $file"; fi; done
MISSING: ./two
MISSING: three.txt

Pathname expansion (globbing) provides a much better/safer way to keep track of files. Then you can also use bash arrays:

$ a=( *.txt *.bmp )
$ declare -p a
declare -a a=([0]="one.txt" [1]="two three.txt" [2]="foo.bmp")
$ for file in "${a[@]}"; do ls -l "$file"; done
-rw-r--r--  1 ghoti  staff  0 24 May 16:27 one.txt
-rw-r--r--  1 ghoti  staff  0 24 May 16:27 two three.txt
-rw-r--r--  1 ghoti  staff  0 24 May 16:27 foo.bmp

The Bash FAQ has lots of other excellent tips about programming in bash.

MySQL: Curdate() vs Now()

Actually MySQL provide a lot of easy to use function in daily life without more effort from user side-

NOW() it produce date and time both in current scenario whereas CURDATE() produce date only, CURTIME() display time only, we can use one of them according to our need with CAST or merge other calculation it, MySQL rich in these type of function.

NOTE:- You can see the difference using query select NOW() as NOWDATETIME, CURDATE() as NOWDATE, CURTIME() as NOWTIME ;

How To Execute SSH Commands Via PHP

For those using the Symfony framework, the phpseclib can also be used to connect via SSH. It can be installed using composer:

composer require phpseclib/phpseclib

Next, simply use it as follows:

use phpseclib\Net\SSH2;

// Within a controller for example:
$ssh = new SSH2('hostname or ip');
if (!$ssh->login('username', 'password')) {
    // Login failed, do something
}

$return_value = $ssh->exec('command');

convert '1' to '0001' in JavaScript

String.prototype.padZero= function(len, c){
    var s= this, c= c || '0';
    while(s.length< len) s= c+ s;
    return s;
}

dispite the name, you can left-pad with any character, including a space. I never had a use for right side padding, but that would be easy enough.

HTML table with horizontal scrolling (first column fixed)

I have a similar table styled like so:

<table style="width:100%; table-layout:fixed">
    <tr>
        <td style="width: 150px">Hello, World!</td>
        <td>
            <div>
                <pre style="margin:0; overflow:scroll">My preformatted content</pre>
            </div>
        </td>
    </tr>
</table>

How do you get git to always pull from a specific branch?

Not wanting to edit my git config file I followed the info in @mipadi's post and used:

$ git pull origin master

Javascript get Object property Name

If you want to get the key name of myVar object then you can use Object.keys() for this purpose.

var result = Object.keys(myVar); 

alert(result[0]) // result[0] alerts typeA

Fatal error: Call to undefined function mcrypt_encrypt()

If you using ubuntu 14.04 here is the fix to this problem:

First check php5-mcryp is already installed apt-get install php5-mcrypt

If installed, just run this two command or install and run this two command

$ sudo php5enmod mcrypt
$ sudo service apache2 restart

I hope it will work.

codes for ADD,EDIT,DELETE,SEARCH in vb2010

Have you googled about it - insert update delete access vb.net, there are lots of reference about this.

Insert Update Delete Navigation & Searching In Access Database Using VB.NET

  • Create Visual Basic 2010 Project: VB-Access
  • Assume that, we have a database file named data.mdb
  • Place the data.mdb file into ..\bin\Debug\ folder (Where the project executable file (.exe) is placed)

what could be the easier way to connect and manipulate the DB?
Use OleDBConnection class to make connection with DB

is it by using MS ACCESS 2003 or MS ACCESS 2007?
you can use any you want to use or your client will use on their machine.

it seems that you want to find some example of opereations fo the database. Here is an example of Access 2010 for your reference:

Example code snippet:

Imports System
Imports System.Data
Imports System.Data.OleDb

Public Class DBUtil

 Private connectionString As String

 Public Sub New()

  Dim con As New OleDb.OleDbConnection
  Dim dbProvider As String = "Provider=Microsoft.ace.oledb.12.0;"
  Dim dbSource = "Data Source=d:\DB\Database11.accdb"

  connectionString = dbProvider & dbSource

 End Sub

 Public Function GetCategories() As DataSet

  Dim query As String = "SELECT * FROM Categories"
  Dim cmd As New OleDbCommand(query)
  Return FillDataSet(cmd, "Categories")

 End Function

 Public SubUpdateCategories(ByVal name As String)
  Dim query As String = "update Categories set name = 'new2' where name = ?"
  Dim cmd As New OleDbCommand(query)
cmd.Parameters.AddWithValue("Name", name)
  Return FillDataSet(cmd, "Categories")

 End Sub

 Public Function GetItems() As DataSet

  Dim query As String = "SELECT * FROM Items"
  Dim cmd As New OleDbCommand(query)
  Return FillDataSet(cmd, "Items")

 End Function

 Public Function GetItems(ByVal categoryID As Integer) As DataSet

  'Create the command.
  Dim query As String = "SELECT * FROM Items WHERE Category_ID=?"
  Dim cmd As New OleDbCommand(query)
  cmd.Parameters.AddWithValue("category_ID", categoryID)

  'Fill the dataset.
  Return FillDataSet(cmd, "Items")

 End Function

 Public Sub AddCategory(ByVal name As String)

  Dim con As New OleDbConnection(connectionString)

  'Create the command.
  Dim insertSQL As String = "INSERT INTO Categories "
  insertSQL &= "VALUES(?)"
  Dim cmd As New OleDbCommand(insertSQL, con)
  cmd.Parameters.AddWithValue("Name", name)

  Try
   con.Open()
   cmd.ExecuteNonQuery()
  Finally
   con.Close()
  End Try

 End Sub

 Public Sub AddItem(ByVal title As String, ByVal description As String, _
    ByVal price As Decimal, ByVal categoryID As Integer)

  Dim con As New OleDbConnection(connectionString)

  'Create the command.
  Dim insertSQL As String = "INSERT INTO Items "
  insertSQL &= "(Title, Description, Price, Category_ID)"
  insertSQL &= "VALUES (?, ?, ?, ?)"
  Dim cmd As New OleDb.OleDbCommand(insertSQL, con)
  cmd.Parameters.AddWithValue("Title", title)
  cmd.Parameters.AddWithValue("Description", description)
  cmd.Parameters.AddWithValue("Price", price)
  cmd.Parameters.AddWithValue("CategoryID", categoryID)

  Try
   con.Open()
   cmd.ExecuteNonQuery()
  Finally
   con.Close()
  End Try

 End Sub

 Private Function FillDataSet(ByVal cmd As OleDbCommand, ByVal tableName As String) As DataSet

  Dim con As New OleDb.OleDbConnection
  Dim dbProvider As String = "Provider=Microsoft.ace.oledb.12.0;"
  Dim dbSource = "Data Source=D:\DB\Database11.accdb"

  connectionString = dbProvider & dbSource
  con.ConnectionString = connectionString
  cmd.Connection = con
  Dim adapter As New OleDbDataAdapter(cmd)
  Dim ds As New DataSet()

  Try
   con.Open()
   adapter.Fill(ds, tableName)
  Finally
   con.Close()
  End Try
  Return ds

 End Function

End Class

Refer these links:
Insert, Update, Delete & Search Values in MS Access 2003 with VB.NET 2005
INSERT, DELETE, UPDATE AND SELECT Data in MS-Access with VB 2008
How Add new record ,Update record,Delete Records using Vb.net Forms when Access as a back

How can I undo a mysql statement that I just executed?

If you define table type as InnoDB, you can use transactions. You will need set AUTOCOMMIT=0, and after you can issue COMMIT or ROLLBACK at the end of query or session to submit or cancel a transaction.

ROLLBACK -- will undo the changes that you have made

How to overwrite existing files in batch?

you need to simply add /Y

xcopy /s c:\mmyinbox\test.doc C:\myoutbox /Y

and if you're using path with spaces, try this

xcopy /s "c:\mmyinbox\test.doc" "C:\myoutbox" /Y

MVC Form not able to post List of objects

Please read this: http://haacked.com/archive/2008/10/23/model-binding-to-a-list.aspx
You should set indicies for your html elements "name" attributes like planCompareViewModel[0].PlanId, planCompareViewModel[1].PlanId to make binder able to parse them into IEnumerable.
Instead of @foreach (var planVM in Model) use for loop and render names with indexes.

How to convert int to QString?

Just for completeness, you can use the standard library and do QString qstr = QString::fromStdString(std::to_string(42));

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

As far as the best algorithm goes you probably have it right. I would recommend that you unravel the recursive function and use a stack of your own (remember a stack overflow is the end of the world in a .Net 2.0+ app, the exception can not be caught IIRC).

The most important thing is that if you are using it in any form of a UI put it on a worker thread that signals the UI thread with updates.

How to upload, display and save images using node.js and express

First of all, you should make an HTML form containing a file input element. You also need to set the form's enctype attribute to multipart/form-data:

<form method="post" enctype="multipart/form-data" action="/upload">
    <input type="file" name="file">
    <input type="submit" value="Submit">
</form>

Assuming the form is defined in index.html stored in a directory named public relative to where your script is located, you can serve it this way:

const http = require("http");
const path = require("path");
const fs = require("fs");

const express = require("express");

const app = express();
const httpServer = http.createServer(app);

const PORT = process.env.PORT || 3000;

httpServer.listen(PORT, () => {
  console.log(`Server is listening on port ${PORT}`);
});

// put the HTML file containing your form in a directory named "public" (relative to where this script is located)
app.get("/", express.static(path.join(__dirname, "./public")));

Once that's done, users will be able to upload files to your server via that form. But to reassemble the uploaded file in your application, you'll need to parse the request body (as multipart form data).

In Express 3.x you could use express.bodyParser middleware to handle multipart forms but as of Express 4.x, there's no body parser bundled with the framework. Luckily, you can choose from one of the many available multipart/form-data parsers out there. Here, I'll be using multer:

You need to define a route to handle form posts:

const multer = require("multer");

const handleError = (err, res) => {
  res
    .status(500)
    .contentType("text/plain")
    .end("Oops! Something went wrong!");
};

const upload = multer({
  dest: "/path/to/temporary/directory/to/store/uploaded/files"
  // you might also want to set some limits: https://github.com/expressjs/multer#limits
});


app.post(
  "/upload",
  upload.single("file" /* name attribute of <file> element in your form */),
  (req, res) => {
    const tempPath = req.file.path;
    const targetPath = path.join(__dirname, "./uploads/image.png");

    if (path.extname(req.file.originalname).toLowerCase() === ".png") {
      fs.rename(tempPath, targetPath, err => {
        if (err) return handleError(err, res);

        res
          .status(200)
          .contentType("text/plain")
          .end("File uploaded!");
      });
    } else {
      fs.unlink(tempPath, err => {
        if (err) return handleError(err, res);

        res
          .status(403)
          .contentType("text/plain")
          .end("Only .png files are allowed!");
      });
    }
  }
);

In the example above, .png files posted to /upload will be saved to uploaded directory relative to where the script is located.

In order to show the uploaded image, assuming you already have an HTML page containing an img element:

<img src="/image.png" />

you can define another route in your express app and use res.sendFile to serve the stored image:

app.get("/image.png", (req, res) => {
  res.sendFile(path.join(__dirname, "./uploads/image.png"));
});

How do I generate random numbers in Dart?

Use Random class from dart:math:

import 'dart:math';

main() {
  var rng = new Random();
  for (var i = 0; i < 10; i++) {
    print(rng.nextInt(100));
  }
}

This code was tested with the Dart VM and dart2js, as of the time of this writing.

Add a fragment to the URL without causing a redirect?

window.location.hash = 'something';

That is just plain JavaScript.

Your comment...

Hi, what I really need is to add only the hash... something like this: window.location.hash = '#'; but in this way nothing is added.

Try this...

window.location = '#';

Also, don't forget about the window.location.replace() method.

SHA512 vs. Blowfish and Bcrypt

I would recommend Ulrich Drepper's SHA-256/SHA-512 based crypt implementation.

We ported these algorithms to Java, and you can find a freely licensed version of them at ftp://ftp.arlut.utexas.edu/java_hashes/.

Note that most modern (L)Unices support Drepper's algorithm in their /etc/shadow files.

SQL Query to search schema of all tables

You can also try doing this using one of many third party tools that are available for this.

Queries are great for simple searches but if you need to do more manipulation with data, search for references and such this is where you can do a much better job with these.

Also, these come in very handy when some objects are encrypted and you need to search for

I’m using ApexSQL Search which is free but there are also many more (also free) on the market such as Red Gate or SSMS Tool Pack.

Difference between database and schema

A database is the main container, it contains the data and log files, and all the schemas within it. You always back up a database, it is a discrete unit on its own.

Schemas are like folders within a database, and are mainly used to group logical objects together, which leads to ease of setting permissions by schema.

EDIT for additional question

drop schema test1

Msg 3729, Level 16, State 1, Line 1
Cannot drop schema 'test1' because it is being referenced by object 'copyme'.

You cannot drop a schema when it is in use. You have to first remove all objects from the schema.

Related reading:

  1. What good are SQL Server schemas?
  2. MSDN: User-Schema Separation

How do I check if a property exists on a dynamic anonymous type in c#?

Using reflection, this is the function i use :

public static bool doesPropertyExist(dynamic obj, string property)
{
    return ((Type)obj.GetType()).GetProperties().Where(p => p.Name.Equals(property)).Any();
}

then..

if (doesPropertyExist(myDynamicObject, "myProperty")){
    // ...
}

Twitter Bootstrap tabs not working: when I click on them nothing happens

I have the same problem, but above some answers might be tricky for me.

I found the other answer maybe solve your question Twitter Bootstrap Js (tabs, popups, dropdown) not working in Drupal

place jquery.js before bootstrap.tab.js

Rebuild or regenerate 'ic_launcher.png' from images in Android Studio

In Android studio 0.8 and after Right click on app folder then New > Image Asset

Browse for best resolution image you have in "Image file" field

hit Next The rest will be generated

'' is not recognized as an internal or external command, operable program or batch file

When you want to run an executable file from the Command prompt, (cmd.exe), or a batch file, it will:

  • Search the current working directory for the executable file.
  • Search all locations specified in the %PATH% environment variable for the executable file.

If the file isn't found in either of those options you will need to either:

  1. Specify the location of your executable.
  2. Change the working directory to that which holds the executable.
  3. Add the location to %PATH% by apending it, (recommended only with extreme caution).

You can see which locations are specified in %PATH% from the Command prompt, Echo %Path%.

Because of your reported error we can assume that Mobile.exe is not in the current directory or in a location specified within the %Path% variable, so you need to use 1., 2. or 3..

Examples for 1.

C:\directory_path_without_spaces\My-App\Mobile.exe

or:

"C:\directory path with spaces\My-App\Mobile.exe"

Alternatively you may try:

Start C:\directory_path_without_spaces\My-App\Mobile.exe

or

Start "" "C:\directory path with spaces\My-App\Mobile.exe"

Where "" is an empty title, (you can optionally add a string between those doublequotes).

Examples for 2.

CD /D C:\directory_path_without_spaces\My-App
Mobile.exe

or

CD /D "C:\directory path with spaces\My-App"
Mobile.exe

You could also use the /D option with Start to change the working directory for the executable to be run by the start command

Start /D C:\directory_path_without_spaces\My-App Mobile.exe

or

Start "" /D "C:\directory path with spaces\My-App" Mobile.exe

how to clear JTable

This is the fastest and easiest way that I have found;

while (tableModel.getRowCount()>0)
          {
             tableModel.removeRow(0);
          }

This clears the table lickety split and leaves it ready for new data.

How to set default value to the input[type="date"]

<input type="date" id="myDate" />

Then in js :

_today: function () {
  var myDate = document.querySelector(myDate);
  var today = new Date();
  myDate.value = today.toISOString().substr(0, 10);
},

How to join two JavaScript Objects, without using JQUERY

This simple function recursively merges JSON objects, please notice that this function merges all JSON into first param (target), if you need new object modify this code.

var mergeJSON = function (target, add) {
    function isObject(obj) {
        if (typeof obj == "object") {
            for (var key in obj) {
                if (obj.hasOwnProperty(key)) {
                    return true; // search for first object prop
                }
            }
        }
        return false;
    }
    for (var key in add) {
        if (add.hasOwnProperty(key)) {
            if (target[key] && isObject(target[key]) && isObject(add[key])) {
                this.mergeJSON(target[key], add[key]);
            } else {
                target[key] = add[key];
            }
        }
    }
    return target;
};

BTW instead of isObject() function may be used condition like this:

JSON.stringify(add[key])[0] == "{"

but this is not good solution, because it's will take a lot of resources if we have large JSON objects.