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Comparing two NumPy arrays for equality, element-wise

(A==B).all()

test if all values of array (A==B) are True.

Note: maybe you also want to test A and B shape, such as A.shape == B.shape

Special cases and alternatives (from dbaupp's answer and yoavram's comment)

It should be noted that:

  • this solution can have a strange behavior in a particular case: if either A or B is empty and the other one contains a single element, then it return True. For some reason, the comparison A==B returns an empty array, for which the all operator returns True.
  • Another risk is if A and B don't have the same shape and aren't broadcastable, then this approach will raise an error.

In conclusion, if you have a doubt about A and B shape or simply want to be safe: use one of the specialized functions:

np.array_equal(A,B)  # test if same shape, same elements values
np.array_equiv(A,B)  # test if broadcastable shape, same elements values
np.allclose(A,B,...) # test if same shape, elements have close enough values

Opening popup windows in HTML

HTML alone does not support this. You need to use some JS.

And also consider nowadays people use popup blocker in browsers.

<a href="javascript:window.open('document.aspx','mypopuptitle','width=600,height=400')">open popup</a>

ojdbc14.jar vs. ojdbc6.jar

Also, from ojdbc14 to ojdbc6, several types (e.g., OracleResultSet, OracleStatement) moved from package oracle.jdbc.driver to oracle.jdbc.

SQL grammar for SELECT MIN(DATE)

To get the titles for dates greater than a week ago today, use this:

SELECT title, MIN(date_key_no) AS intro_date FROM table HAVING MIN(date_key_no)>= TO_NUMBER(TO_CHAR(SysDate, 'YYYYMMDD')) - 7

How to create a zip archive with PowerShell?

Giving below another option. This will zip up a full folder and will write the archive to a given path with the given name.

Requires .NET 3 or above

Add-Type -assembly "system.io.compression.filesystem"

$source = 'Source path here'    
$destination = "c:\output\dummy.zip"

If(Test-path $destination) {Remove-item $destination}

[io.compression.zipfile]::CreateFromDirectory($Source, $destination)

How do I kill a process using Vb.NET or C#?

    public bool FindAndKillProcess(string name)
    {
        //here we're going to get a list of all running processes on
        //the computer
        foreach (Process clsProcess in Process.GetProcesses()) {
            //now we're going to see if any of the running processes
            //match the currently running processes by using the StartsWith Method,
            //this prevents us from incluing the .EXE for the process we're looking for.
            //. Be sure to not
            //add the .exe to the name you provide, i.e: NOTEPAD,
            //not NOTEPAD.EXE or false is always returned even if
            //notepad is running
            if (clsProcess.ProcessName.StartsWith(name))
            {
                //since we found the proccess we now need to use the
                //Kill Method to kill the process. Remember, if you have
                //the process running more than once, say IE open 4
                //times the loop thr way it is now will close all 4,
                //if you want it to just close the first one it finds
                //then add a return; after the Kill
                try 
                {
                    clsProcess.Kill();
                }
                catch
                {
                    return false;
                }
                //process killed, return true
                return true;
            }
        }
        //process not found, return false
        return false;
    }

Jquery DatePicker Set default date

Code to display current date in element input or datepicker with ID="mydate"

Don't forget add reference to jquery-ui-*.js

    $(document).ready(function () {
        var dateNewFormat, onlyDate, today = new Date();

        dateNewFormat = today.getFullYear() + '-' + (today.getMonth() + 1);

        onlyDate = today.getDate();

        if (onlyDate.toString().length == 2) {
            dateNewFormat += '-' + onlyDate;
        }
        else {
            dateNewFormat += '-0' + onlyDate;
        }
        $('#mydate').val(dateNewFormat);
    });

Fill background color left to right CSS

A single css code on hover can do the trick: box-shadow: inset 100px 0 0 0 #e0e0e0;

A complete demo can be found in my fiddle:

https://jsfiddle.net/shuvamallick/3o0h5oka/

Angular2: How to load data before rendering the component?

You can pre-fetch your data by using Resolvers in Angular2+, Resolvers process your data before your Component fully be loaded.

There are many cases that you want to load your component only if there is certain thing happening, for example navigate to Dashboard only if the person already logged in, in this case Resolvers are so handy.

Look at the simple diagram I created for you for one of the way you can use the resolver to send the data to your component.

enter image description here

Applying Resolver to your code is pretty simple, I created the snippets for you to see how the Resolver can be created:

import { Injectable } from '@angular/core';
import { Router, Resolve, RouterStateSnapshot, ActivatedRouteSnapshot } from '@angular/router';
import { MyData, MyService } from './my.service';

@Injectable()
export class MyResolver implements Resolve<MyData> {
  constructor(private ms: MyService, private router: Router) {}

  resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Promise<MyData> {
    let id = route.params['id'];

    return this.ms.getId(id).then(data => {
      if (data) {
        return data;
      } else {
        this.router.navigate(['/login']);
        return;
      }
    });
  }
}

and in the module:

import { MyResolver } from './my-resolver.service';

@NgModule({
  imports: [
    RouterModule.forChild(myRoutes)
  ],
  exports: [
    RouterModule
  ],
  providers: [
    MyResolver
  ]
})
export class MyModule { }

and you can access it in your Component like this:

/////
 ngOnInit() {
    this.route.data
      .subscribe((data: { mydata: myData }) => {
        this.id = data.mydata.id;
      });
  }
/////

And in the Route something like this (usually in the app.routing.ts file):

////
{path: 'yourpath/:id', component: YourComponent, resolve: { myData: MyResolver}}
////

Change auto increment starting number?

You can use ALTER TABLE to change the auto_increment initial value:

ALTER TABLE tbl AUTO_INCREMENT = 5;

See the MySQL reference for more details.

Create a string of variable length, filled with a repeated character

A great ES6 option would be to padStart an empty string. Like this:

var str = ''.padStart(10, "#");

Note: this won't work in IE (without a polyfill).

How to use forEach in vueJs?

This is an example of forEach usage:

let arr = [];

this.myArray.forEach((value, index) => {
    arr.push(value);
    console.log(value);
    console.log(index);
});

In this case, "myArray" is an array on my data.

You can also loop through an array using filter, but this one should be used if you want to get a new list with filtered elements of your array.

Something like this:

const newArray = this.myArray.filter((value, index) => {
    console.log(value);
    console.log(index);
    if (value > 5) return true;
});

and the same can be written as:

const newArray = this.myArray.filter((value, index) => value > 5);

Both filter and forEach are javascript methods and will work just fine with VueJs. Also, it might be interesting taking a look at this:

https://developer.mozilla.org/pt-BR/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach

Content-Disposition:What are the differences between "inline" and "attachment"?

It might also be worth mentioning that inline will try to open Office Documents (xls, doc etc) directly from the server, which might lead to a User Credentials Prompt.

see this link:

http://forums.asp.net/t/1885657.aspx/1?Access+the+SSRS+Report+in+excel+format+on+server

somebody tried to deliver an Excel Report from SSRS via ASP.Net -> the user always got prompted to enter the credentials. After clicking cancel on the prompt it would be opened anyway...

If the Content Disposition is marked as Attachment it will automatically be saved to the temp folder after clicking open and then opened in Excel from the local copy.

chrome undo the action of "prevent this page from creating additional dialogs"

Close the tab of the page you disabled alerts. Re-open the page in a new tab. The setting only lasts for the session, so alerts will be re-enabled once the new session begins in the new tab.

How to Use -confirm in PowerShell

Here is the documentation from Microsoft on how to request confirmations in a cmdlet. The examples are in C#, but you can do everything shown in PowerShell as well.

First add the CmdletBinding attribute to your function and set SupportsShouldProcess to true. Then you can reference the ShouldProcess and ShouldContinue methods of the $PSCmdlet variable.

Here is an example:

function Start-Work {
    <#
    .SYNOPSIS Does some work
    .PARAMETER Force
        Perform the operation without prompting for confirmation
    #>
    [CmdletBinding(SupportsShouldProcess=$true)]
    param(
        # This switch allows the user to override the prompt for confirmation
        [switch]$Force
    )
    begin { }
    process {
        if ($PSCmdlet.ShouldProcess('Target')) {
            if (-not ($Force -or $PSCmdlet.ShouldContinue('Do you want to continue?', 'Caption'))) {
                return # user replied no
            }

            # Do work
        }

    }
    end { }
}

Differences between arm64 and aarch64

AArch64 is the 64-bit state introduced in the Armv8-A architecture (https://en.wikipedia.org/wiki/ARM_architecture#ARMv8-A). The 32-bit state which is backwards compatible with Armv7-A and previous 32-bit Arm architectures is referred to as AArch32. Therefore the GNU triplet for the 64-bit ISA is aarch64. The Linux kernel community chose to call their port of the kernel to this architecture arm64 rather than aarch64, so that's where some of the arm64 usage comes from.

As far as I know the Apple backend for aarch64 was called arm64 whereas the LLVM community-developed backend was called aarch64 (as it is the canonical name for the 64-bit ISA) and later the two were merged and the backend now is called aarch64.

So AArch64 and ARM64 refer to the same thing.

This version of Android Studio cannot open this project, please retry with Android Studio 3.4 or newer

It's a bit late, But easy and effective. Click on About Android Studio, Check the current version, Open build.graddle of Project and put it in front of the class path. e.g Your studio version is 3.5.2, then your classpath should be like that.

classpath 'com.android.tools.build:gradle:3.5.2'

Temporarily switch working copy to a specific Git commit

In addition to the other answers here showing you how to git checkout <the-hash-you-want> it's worth knowing you can switch back to where you were using:

git checkout @{-1}

This is often more convenient than:

git checkout what-was-that-original-branch-called-again-question-mark

As you might anticipate, git checkout @{-2} will take you back to the branch you were at two git checkouts ago, and similarly for other numbers. If you can remember where you were for bigger numbers, you should get some kind of medal for that.


Sadly for productivity, git checkout @{1} does not take you to the branch you will be on in future, which is a shame.

String comparison in bash. [[: not found

How you are running your script? If you did with

$ sh myscript

you should try:

$ bash myscript

or, if the script is executable:

$ ./myscript

sh and bash are two different shells. While in the first case you are passing your script as an argument to the sh interpreter, in the second case you decide on the very first line which interpreter will be used.

How do I copy a folder from remote to local using scp?

scp -r [email protected]:/path/to/foo /home/user/Desktop/

By not including the trailing '/' at the end of foo, you will copy the directory itself (including contents), rather than only the contents of the directory.

From man scp (See online manual)

-r Recursively copy entire directories

Fill SVG path element with a background-image

You can do it by making the background into a pattern:

<defs>
  <pattern id="img1" patternUnits="userSpaceOnUse" width="100" height="100">
    <image href="wall.jpg" x="0" y="0" width="100" height="100" />
  </pattern>
</defs>

Adjust the width and height according to your image, then reference it from the path like this:

<path d="M5,50
         l0,100 l100,0 l0,-100 l-100,0
         M215,100
         a50,50 0 1 1 -100,0 50,50 0 1 1 100,0
         M265,50
         l50,100 l-100,0 l50,-100
         z"
  fill="url(#img1)" />

Working example

Digital Certificate: How to import .cer file in to .truststore file using?

The way you import a .cer file into the trust store is the same way you'd import a .crt file from say an export from Firefox.

You do not have to put an alias and the password of the keystore, you can just type:

keytool -v -import -file somefile.crt  -alias somecrt -keystore my-cacerts

Preferably use the cacerts file that is already in your Java installation (jre\lib\security\cacerts) as it contains secure "popular" certificates.

Update regarding the differences of cer and crt (just to clarify) According to Apache with SSL - How to convert CER to CRT certificates? and user @Spawnrider

CER is a X.509 certificate in binary form, DER encoded.
CRT is a binary X.509 certificate, encapsulated in text (base-64) encoding.
It is not the same encoding.

How does Content Security Policy (CSP) work?

The Content-Security-Policy meta-tag allows you to reduce the risk of XSS attacks by allowing you to define where resources can be loaded from, preventing browsers from loading data from any other locations. This makes it harder for an attacker to inject malicious code into your site.

I banged my head against a brick wall trying to figure out why I was getting CSP errors one after another, and there didn't seem to be any concise, clear instructions on just how does it work. So here's my attempt at explaining some points of CSP briefly, mostly concentrating on the things I found hard to solve.

For brevity I won’t write the full tag in each sample. Instead I'll only show the content property, so a sample that says content="default-src 'self'" means this:

<meta http-equiv="Content-Security-Policy" content="default-src 'self'">

1. How can I allow multiple sources?

You can simply list your sources after a directive as a space-separated list:

content="default-src 'self' https://example.com/js/"

Note that there are no quotes around parameters other than the special ones, like 'self'. Also, there's no colon (:) after the directive. Just the directive, then a space-separated list of parameters.

Everything below the specified parameters is implicitly allowed. That means that in the example above these would be valid sources:

https://example.com/js/file.js
https://example.com/js/subdir/anotherfile.js

These, however, would not be valid:

http://example.com/js/file.js
^^^^ wrong protocol

https://example.com/file.js
                   ^^ above the specified path

2. How can I use different directives? What do they each do?

The most common directives are:

  • default-src the default policy for loading javascript, images, CSS, fonts, AJAX requests, etc
  • script-src defines valid sources for javascript files
  • style-src defines valid sources for css files
  • img-src defines valid sources for images
  • connect-src defines valid targets for to XMLHttpRequest (AJAX), WebSockets or EventSource. If a connection attempt is made to a host that's not allowed here, the browser will emulate a 400 error

There are others, but these are the ones you're most likely to need.

3. How can I use multiple directives?

You define all your directives inside one meta-tag by terminating them with a semicolon (;):

content="default-src 'self' https://example.com/js/; style-src 'self'"

4. How can I handle ports?

Everything but the default ports needs to be allowed explicitly by adding the port number or an asterisk after the allowed domain:

content="default-src 'self' https://ajax.googleapis.com http://example.com:123/free/stuff/"

The above would result in:

https://ajax.googleapis.com:123
                           ^^^^ Not ok, wrong port

https://ajax.googleapis.com - OK

http://example.com/free/stuff/file.js
                 ^^ Not ok, only the port 123 is allowed

http://example.com:123/free/stuff/file.js - OK

As I mentioned, you can also use an asterisk to explicitly allow all ports:

content="default-src example.com:*"

5. How can I handle different protocols?

By default, only standard protocols are allowed. For example to allow WebSockets ws:// you will have to allow it explicitly:

content="default-src 'self'; connect-src ws:; style-src 'self'"
                                         ^^^ web Sockets are now allowed on all domains and ports.

6. How can I allow the file protocol file://?

If you'll try to define it as such it won’t work. Instead, you'll allow it with the filesystem parameter:

content="default-src filesystem"

7. How can I use inline scripts and style definitions?

Unless explicitly allowed, you can't use inline style definitions, code inside <script> tags or in tag properties like onclick. You allow them like so:

content="script-src 'unsafe-inline'; style-src 'unsafe-inline'"

You'll also have to explicitly allow inline, base64 encoded images:

content="img-src data:"

8. How can I allow eval()?

I'm sure many people would say that you don't, since 'eval is evil' and the most likely cause for the impending end of the world. Those people would be wrong. Sure, you can definitely punch major holes into your site's security with eval, but it has perfectly valid use cases. You just have to be smart about using it. You allow it like so:

content="script-src 'unsafe-eval'"

9. What exactly does 'self' mean?

You might take 'self' to mean localhost, local filesystem, or anything on the same host. It doesn't mean any of those. It means sources that have the same scheme (protocol), same host, and same port as the file the content policy is defined in. Serving your site over HTTP? No https for you then, unless you define it explicitly.

I've used 'self' in most examples as it usually makes sense to include it, but it's by no means mandatory. Leave it out if you don't need it.

But hang on a minute! Can't I just use content="default-src *" and be done with it?

No. In addition to the obvious security vulnerabilities, this also won’t work as you'd expect. Even though some docs claim it allows anything, that's not true. It doesn't allow inlining or evals, so to really, really make your site extra vulnerable, you would use this:

content="default-src * 'unsafe-inline' 'unsafe-eval'"

... but I trust you won’t.

Further reading:

http://content-security-policy.com

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

Returning a pointer to a vector element in c++

As long as your vector remains in global scope you can return:

&(*iterator)

I'll caution you that this is pretty dangerous in general. If your vector is ever moved out of global scope and is destructed, any pointers to myObject become invalid. If you're writing these functions as part of a larger project, returning a non-const pointer could lead someone to delete the return value. This will have undefined, and catastrophic, effects on the application.

I'd rewrite this as:

myObject myFunction(const vector<myObject>& objects)
{
    // find the object in question and return a copy
    return *iterator;
}

If you need to modify the returned myObject, store your values as pointers and allocate them on the heap:

myObject* myFunction(const vector<myObject*>& objects)
{
    return *iterator;
}

That way you have control over when they're destructed.

Something like this will break your app:

g_vector<tmpClass> myVector;

    tmpClass t;
    t.i = 30;
    myVector.push_back(t);

    // my function returns a pointer to a value in myVector
    std::auto_ptr<tmpClass> t2(myFunction());

Check if a String is in an ArrayList of Strings

    List list1 = new ArrayList();
    list1.add("one");
    list1.add("three");
    list1.add("four");

    List list2 = new ArrayList();
    list2.add("one");
    list2.add("two");
    list2.add("three");
    list2.add("four");
    list2.add("five");


    list2.stream().filter( x -> !list1.contains(x) ).forEach(x -> System.out.println(x));

The output is:

two
five

C# catch a stack overflow exception

You can't. The CLR won't let you. A stack overflow is a fatal error and can't be recovered from.

how to check the version of jar file?

This simple program will list all the cases for version of jar namely

  • Version found in Manifest file
  • No version found in Manifest and even from jar name
  • Manifest file not found

    Map<String, String> jarsWithVersionFound   = new LinkedHashMap<String, String>();
    List<String> jarsWithNoManifest     = new LinkedList<String>();
    List<String> jarsWithNoVersionFound = new LinkedList<String>();
    
    //loop through the files in lib folder
    //pick a jar one by one and getVersion()
    //print in console..save to file(?)..maybe later
    
    File[] files = new File("path_to_jar_folder").listFiles();
    
    for(File file : files)
    {
        String fileName = file.getName();
    
    
        try
        {
            String jarVersion = new Jar(file).getVersion();
    
            if(jarVersion == null)
                jarsWithNoVersionFound.add(fileName);
            else
                jarsWithVersionFound.put(fileName, jarVersion);
    
        }
        catch(Exception ex)
        {
            jarsWithNoManifest.add(fileName);
        }
    }
    
    System.out.println("******* JARs with versions found *******");
    for(Entry<String, String> jarName : jarsWithVersionFound.entrySet())
        System.out.println(jarName.getKey() + " : " + jarName.getValue());
    
    System.out.println("\n \n ******* JARs with no versions found *******");
    for(String jarName : jarsWithNoVersionFound)
        System.out.println(jarName);
    
    System.out.println("\n \n ******* JARs with no manifest found *******");
    for(String jarName : jarsWithNoManifest)
        System.out.println(jarName);
    

It uses the javaxt-core jar which can be downloaded from http://www.javaxt.com/downloads/

How to both read and write a file in C#

Made an improvement code by @Ipsita - for use asynchronous read\write file I/O

readonly string logPath = @"FilePath";
...
public async Task WriteToLogAsync(string dataToWrite)
{
    TextReader tr = new StreamReader(logPath);
    string data = await tr.ReadLineAsync();
    tr.Close();

    TextWriter tw = new StreamWriter(logPath);
    await tw.WriteLineAsync(data + dataToWrite);
    tw.Close();
}
...
await WriteToLogAsync("Write this to file");

Loop through an array of strings in Bash?

You can use it like this:

## declare an array variable
declare -a arr=("element1" "element2" "element3")

## now loop through the above array
for i in "${arr[@]}"
do
   echo "$i"
   # or do whatever with individual element of the array
done

# You can access them using echo "${arr[0]}", "${arr[1]}" also

Also works for multi-line array declaration

declare -a arr=("element1" 
                "element2" "element3"
                "element4"
                )

How, in general, does Node.js handle 10,000 concurrent requests?

I understand that Node.js uses a single-thread and an event loop to process requests only processing one at a time (which is non-blocking).

I could be misunderstanding what you've said here, but "one at a time" sounds like you may not be fully understanding the event-based architecture.

In a "conventional" (non event-driven) application architecture, the process spends a lot of time sitting around waiting for something to happen. In an event-based architecture such as Node.js the process doesn't just wait, it can get on with other work.

For example: you get a connection from a client, you accept it, you read the request headers (in the case of http), then you start to act on the request. You might read the request body, you will generally end up sending some data back to the client (this is a deliberate simplification of the procedure, just to demonstrate the point).

At each of these stages, most of the time is spent waiting for some data to arrive from the other end - the actual time spent processing in the main JS thread is usually fairly minimal.

When the state of an I/O object (such as a network connection) changes such that it needs processing (e.g. data is received on a socket, a socket becomes writable, etc) the main Node.js JS thread is woken with a list of items needing to be processed.

It finds the relevant data structure and emits some event on that structure which causes callbacks to be run, which process the incoming data, or write more data to a socket, etc. Once all of the I/O objects in need of processing have been processed, the main Node.js JS thread will wait again until it's told that more data is available (or some other operation has completed or timed out).

The next time that it is woken, it could well be due to a different I/O object needing to be processed - for example a different network connection. Each time, the relevant callbacks are run and then it goes back to sleep waiting for something else to happen.

The important point is that the processing of different requests is interleaved, it doesn't process one request from start to end and then move onto the next.

To my mind, the main advantage of this is that a slow request (e.g. you're trying to send 1MB of response data to a mobile phone device over a 2G data connection, or you're doing a really slow database query) won't block faster ones.

In a conventional multi-threaded web server, you will typically have a thread for each request being handled, and it will process ONLY that request until it's finished. What happens if you have a lot of slow requests? You end up with a lot of your threads hanging around processing these requests, and other requests (which might be very simple requests that could be handled very quickly) get queued behind them.

There are plenty of others event-based systems apart from Node.js, and they tend to have similar advantages and disadvantages compared with the conventional model.

I wouldn't claim that event-based systems are faster in every situation or with every workload - they tend to work well for I/O-bound workloads, not so well for CPU-bound ones.

MVC razor form with multiple different submit buttons?

The cleanest solution I've found is as follows:

This example is to perform two very different actions; the basic premise is to use the value to pass data to the action.

In your view:

@using (Html.BeginForm("DliAction", "Dli", FormMethod.Post, new { id = "mainForm" }))
{
    if (isOnDli)
    {
        <button name="removeDli" value="@result.WeNo">Remove From DLI</button>
    }
    else
    {
        <button name="performDli" value="@result.WeNo">Perform DLI</button>
    }
}

Then in your action:

    public ActionResult DliAction(string removeDli, string performDli)
    {
        if (string.IsNullOrEmpty(performDli))
        {
            ...
        }
        else if (string.IsNullOrEmpty(removeDli))
        {
            ...
        }

        return View();
    }

This code should be easy to alter in order to achieve variations along the theme, e.g. change the button's name to be the same, then you only need one parameter on the action etc, as can be seen below:

In your view:

@using (Html.BeginForm("DliAction", "Dli", FormMethod.Post, new { id = "mainForm" }))
{

        <button name="weNo" value="@result.WeNo">Process This WeNo</button>

        <button name="weNo" value="@result.WeNo">Process A Different WeNo This Item</button>
}

Then in your action:

    public ActionResult DliAction(string weNo)
    {
        // Process the weNo...

        return View();
    }

python pandas convert index to datetime

Doing

df.index = pd.to_datetime(df.index, errors='coerce')

the data type of the index has changed to

dataframe information

Finding sum of elements in Swift array

This is the easiest/shortest method I can find.

Swift 3 and Swift 4:

let multiples = [...]
let sum = multiples.reduce(0, +)
print("Sum of Array is : ", sum)

Swift 2:

let multiples = [...]
sum = multiples.reduce(0, combine: +)

Some more info:

This uses Array's reduce method (documentation here), which allows you to "reduce a collection of elements down to a single value by recursively applying the provided closure". We give it 0 as the initial value, and then, essentially, the closure { $0 + $1 }. Of course, we can simplify that to a single plus sign, because that's how Swift rolls.

How to convert SSH keypairs generated using PuTTYgen (Windows) into key-pairs used by ssh-agent and Keychain (Linux)

PPK ? OpenSSH RSA with PuttyGen & Docker.

Private key:

docker run --rm -v $(pwd):/app zinuzoid/puttygen private.ppk -O private-openssh -o my-openssh-key

Public key:

docker run --rm -v $(pwd):/app zinuzoid/puttygen private.ppk -L -o my-openssh-key.pub

See also https://hub.docker.com/r/zinuzoid/puttygen

Compiler error: memset was not declared in this scope

Whevever you get a problem like this just go to the man page for the function in question and it will tell you what header you are missing, e.g.

$ man memset

MEMSET(3)                BSD Library Functions Manual                MEMSET(3)

NAME
     memset -- fill a byte string with a byte value

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <string.h>

     void *
     memset(void *b, int c, size_t len);

Note that for C++ it's generally preferable to use the proper equivalent C++ headers, <cstring>/<cstdio>/<cstdlib>/etc, rather than C's <string.h>/<stdio.h>/<stdlib.h>/etc.

How do you find out which version of GTK+ is installed on Ubuntu?

This isn't so difficult.

Just check your gtk+ toolkit utilities version from terminal:

gtk-launch --version

TypeScript hashmap/dictionary interface

The most simple and the correct way is to use Record type Record<string, string>

const myVar : Record<string, string> = {
   key1: 'val1',
   key2: 'val2',
}

How can I compare a date and a datetime in Python?

In my case, I get two objects in and I don't know if it's date or timedate objects. Converting to date won't be good as I'd be dropping information - two timedate objects with the same date should be sorted correctly. I'm OK with the dates being sorted before the datetime with same date.

I think I will use strftime before comparing:

>>> foo=datetime.date(2015,1,10)
>>> bar=datetime.datetime(2015,2,11,15,00)
>>> foo.strftime('%F%H%M%S') > bar.strftime('%F%H%M%S')
False
>>> foo.strftime('%F%H%M%S') < bar.strftime('%F%H%M%S')
True

Not elegant, but should work out. I think it would be better if Python wouldn't raise the error, I see no reasons why a datetime shouldn't be comparable with a date. This behaviour is consistent in python2 and python3.

Error : Program type already present: android.support.design.widget.CoordinatorLayout$Behavior

I m using android studio 3.0 and i upgrade the design pattern dependency from 26.0.1 to 27.1.1 and the error is gone now.

Add Following in gradle implementation 'com.android.support:design:27.1.1'

sql query to get earliest date

Using "limit" and "top" will not work with all SQL servers (for example with Oracle). You can try a more complex query in pure sql:

select mt1.id, mt1."name", mt1.score, mt1."date" from mytable mt1
where mt1.id=2
and mt1."date"= (select min(mt2."date") from mytable mt2 where mt2.id=2)

.autocomplete is not a function Error

For my case, my another team member included another version of jquery.js when he add in bootstrap.min.js. After remove the extra jquery.js, the problem is solved

Which tool to build a simple web front-end to my database

The most rapid option is to hand out MS Access or SQL Sever Management Studio (there's a free express edition) along with a read only account.

PHP is simple and has a well earned reputation for getting stuff done. PHP is excellent for copying and pasting code, and you can iterate insanely fast in PHP. PHP can lead to hard-to-maintain applications, and it can be difficult to set up a visual debugger.

Given that you use SQL Server, ASP.NET is also a good option. This is somewhat harder to setup; you'll need an IIS server, with a configured application. Iterations are a bit slower. ASP.NET is easier to maintain and Visual Studio is the best visual debugger around.

MS-DOS Batch file pause with enter key

You can do it with the pause command, example:

dir
pause
echo Now about to end...
pause

postgreSQL - psql \i : how to execute script in a given path

Postgres started on Linux/Unix. I suspect that reversing the slash with fix it.

\i somedir/script2.sql 

If you need to fully qualify something

\i c:/somedir/script2.sql

If that doesn't fix it, my next guess would be you need to escape the backslash.

\i somedir\\script2.sql

Nested rows with bootstrap grid system?

Bootstrap Version 3.x

As always, read Bootstrap's great documentation:

3.x Docs: https://getbootstrap.com/docs/3.3/css/#grid-nesting

Make sure the parent level row is inside of a .container element. Whenever you'd like to nest rows, just open up a new .row inside of your column.

Here's a simple layout to work from:

<div class="container">
    <div class="row">
        <div class="col-xs-6">
            <div class="big-box">image</div>
        </div>
        <div class="col-xs-6">
            <div class="row">
                <div class="col-xs-6"><div class="mini-box">1</div></div>
                <div class="col-xs-6"><div class="mini-box">2</div></div>
                <div class="col-xs-6"><div class="mini-box">3</div></div>
                <div class="col-xs-6"><div class="mini-box">4</div></div>
            </div>
        </div>
    </div>
</div>

Bootstrap Version 4.0

4.0 Docs: http://getbootstrap.com/docs/4.0/layout/grid/#nesting

Here's an updated version for 4.0, but you should really read the entire docs section on the grid so you understand how to leverage this powerful feature

<div class="container">
  <div class="row">
    <div class="col big-box">
      image
    </div>

    <div class="col">
      <div class="row">
        <div class="col mini-box">1</div>
        <div class="col mini-box">2</div>
      </div>
      <div class="row">
        <div class="col mini-box">3</div>
        <div class="col mini-box">4</div>
      </div>
    </div>

  </div>
</div>

Demo in Fiddle jsFiddle 3.x | jsFiddle 4.0

Which will look like this (with a little bit of added styling):

screenshot

How can I decrypt a password hash in PHP?

I need to decrypt a password. The password is crypted with password_hash function.

$password = 'examplepassword';
$crypted = password_hash($password, PASSWORD_DEFAULT);

Its not clear to me if you need password_verify, or you are trying to gain unauthorized access to the application or database. Other have talked about password_verify, so here's how you could gain unauthorized access. Its what bad guys often do when they try to gain access to a system.

First, create a list of plain text passwords. A plain text list can be found in a number of places due to the massive data breaches from companies like Adobe. Sort the list and then take the top 10,000 or 100,000 or so.

Second, create a list of digested passwords. Simply encrypt or hash the password. Based on your code above, it does not look like a salt is being used (or its a fixed salt). This makes the attack very easy.

Third, for each digested password in the list, perform a select in an attempt to find a user who is using the password:

$sql_script = 'select * from USERS where password="'.$digested_password.'"'

Fourth, profit.

So, rather than picking a user and trying to reverse their password, the bad guy picks a common password and tries to find a user who is using it. Odds are on the bad guy's side...

Because the bad guy does these things, it would behove you to not let users choose common passwords. In this case, take a look at ProCheck, EnFilter or Hyppocrates (et al). They are filtering libraries that reject bad passwords. ProCheck achieves very high compression, and can digest multi-million word password lists into a 30KB data file.

Open Url in default web browser

Try this:

import React, { useCallback } from "react";
import { Linking } from "react-native";
OpenWEB = () => {
  Linking.openURL(url);
};

const App = () => {
  return <View onPress={() => OpenWeb}>OPEN YOUR WEB</View>;
};

Hope this will solve your problem.

importing external ".txt" file in python

numpy's genfromtxt or loadtxt is what I use:

import numpy as np
...
wordset = np.genfromtxt(fname='words.txt')

This got me headed in the right direction and solved my problem.

What is a callback in java

In Java, callback methods are mainly used to address the "Observer Pattern", which is closely related to "Asynchronous Programming".

Although callbacks are also used to simulate passing methods as a parameter, like what is done in functional programming languages.

Aborting a stash pop in Git

My use case: just tried popping onto the wrong branch and got conflicts. All I need is to undo the pop but keep it in the stash list so I can pop it out on the correct branch. I did this:

git reset HEAD --hard
git checkout my_correct_branch
git stash pop

Easy.

How to filter by string in JSONPath?

I didn't find find the correct jsonpath filter syntax to extract a value from a name-value pair in json.

Here's the syntax and an abbreviated sample twitter document below.

This site was useful for testing:

The jsonpath filter expression:

.events[0].attributes[?(@.name=='screen_name')].value

Test document:

{
  "title" : "test twitter",
  "priority" : 5,
  "events" : [ {
    "eventId" : "150d3939-1bc4-4bcb-8f88-6153053a2c3e",
    "eventDate" : "2015-03-27T09:07:48-0500",
    "publisher" : "twitter",
    "type" : "tweet",
    "attributes" : [ {
      "name" : "filter_level",
      "value" : "low"
    }, {
      "name" : "screen_name",
      "value" : "_ziadin"
    }, {
      "name" : "followers_count",
      "value" : "406"
    } ]
  } ]
}

Command to change the default home directory of a user

Ibrahim's comment on the other answer is the correct way to alter an existing user's home directory.

Change the user's home directory:

usermod -d /newhome/username username

usermod is the command to edit an existing user.
-d (abbreviation for --home) will change the user's home directory.

Change the user's home directory + Move the contents of the user's current directory:

usermod -m -d /newhome/username username

-m (abbreviation for --move-home) will move the content from the user's current directory to the new directory.

Sort an ArrayList based on an object field

Modify the DataNode class so that it implements Comparable interface.

public int compareTo(DataNode o)
{
     return(degree - o.degree);
}

then just use

Collections.sort(nodeList);

Passing dynamic javascript values using Url.action()

The easiest way is:

  onClick= 'location.href="/controller/action/"+paramterValue'

django import error - No module named core.management

I had this error while trying to run an embedded system (using django of course) on a Raspberry Pi 2 (and not a VM)

Running this:

 sudo pip install Django

Made the trick!

  • just in case a fellow using Raspbian/Jessie gets this

How do I access refs of a child component in the parent component

  1. Inside the child component add a ref to the node you need
  2. Inside the parent component add a ref to the child component.
/*
* Child component
*/
class Child extends React.Component {
  render() {
    return (
      <div id="child">
        <h1 ref={(node) => { this.heading = node; }}>
          Child
        </h1>
      </div>
    );
  }
}

/*
 * Parent component
 */
class Parent extends React.Component {
  componentDidMount() {
    // Access child component refs via parent component instance like this
    console.log(this.child.heading.getDOMNode());
  }

  render() {
    return (
      <div>
        <Child
          ref={(node) => { this.child = node; }}
        />
      </div>
    );
  }
}

Demo: https://codepen.io/itsfadnis/pen/aLWVVx?editors=0011

Is it possible to decompile an Android .apk file?

Sometimes you get broken code, when using dex2jar/apktool, most notably in loops. To avoid this, use jadx, which decompiles dalvik bytecode into java source code, without creating a .jar/.class file first as dex2jar does (apktool uses dex2jar I think). It is also open-source and in active development. It even has a GUI, for GUI-fanatics. Try it!

Parsing HTTP Response in Python

TL&DR: When you typically get data from a server, it is sent in bytes. The rationale is that these bytes will need to be 'decoded' by the recipient, who should know how to use the data. You should decode the binary upon arrival to not get 'b' (bytes) but instead a string.

Use case:

import requests    
def get_data_from_url(url):
        response = requests.get(url_to_visit)
        response_data_split_by_line = response.content.decode('utf-8').splitlines()
        return response_data_split_by_line

In this example, I decode the content that I received into UTF-8. For my purposes, I then split it by line, so I can loop through each line with a for loop.

How to set IntelliJ IDEA Project SDK

For a new project select the home directory of the jdk

eg C:\Java\jdk1.7.0_99 or C:\Program Files\Java\jdk1.7.0_99

For an existing project.

1) You need to have a jdk installed on the system.

for instance in

C:\Java\jdk1.7.0_99

2) go to project structure under File menu ctrl+alt+shift+S

3) SDKs is located under Platform Settings. Select it.

4) click the green + up the top of the window.

5) select JDK (I have to use keyboard to select it do not know why).

select the home directory for your jdk installation.

should be good to go.

What characters are forbidden in Windows and Linux directory names?

Instead of creating a blacklist of characters, you could use a whitelist. All things considered, the range of characters that make sense in a file or directory name context is quite short, and unless you have some very specific naming requirements your users will not hold it against your application if they cannot use the whole ASCII table.

It does not solve the problem of reserved names in the target file system, but with a whitelist it is easier to mitigate the risks at the source.

In that spirit, this is a range of characters that can be considered safe:

  • Letters (a-z A-Z) - Unicode characters as well, if needed
  • Digits (0-9)
  • Underscore (_)
  • Hyphen (-)
  • Space
  • Dot (.)

And any additional safe characters you wish to allow. Beyond this, you just have to enforce some additional rules regarding spaces and dots. This is usually sufficient:

  • Name must contain at least one letter or number (to avoid only dots/spaces)
  • Name must start with a letter or number (to avoid leading dots/spaces)
  • Name may not end with a dot or space (simply trim those if present, like Explorer does)

This already allows quite complex and nonsensical names. For example, these names would be possible with these rules, and be valid file names in Windows/Linux:

  • A...........ext
  • B -.- .ext

In essence, even with so few whitelisted characters you should still decide what actually makes sense, and validate/adjust the name accordingly. In one of my applications, I used the same rules as above but stripped any duplicate dots and spaces.

jQuery - multiple $(document).ready ...?

Execution is top-down. First come, first served.

If execution sequence is important, combine them.

Check if element is clickable in Selenium Java

There are instances when element.isDisplayed() && element.isEnabled() will return true but still element will not be clickable, because it is hidden/overlapped by some other element.

In such case, Exception caught is:

org.openqa.selenium.WebDriverException: unknown error: Element is not clickable at point (781, 704). Other element would receive the click: <div class="footer">...</div>

Use this code instead:

WebElement  element=driver.findElement(By.xpath"");  
JavascriptExecutor ex=(JavascriptExecutor)driver;
ex.executeScript("arguments[0].click()", element);

It will work.

How to write PNG image to string with the PIL?

For Python3 it is required to use BytesIO:

from io import BytesIO
from PIL import Image, ImageDraw

image = Image.new("RGB", (300, 50))
draw = ImageDraw.Draw(image)
draw.text((0, 0), "This text is drawn on image")

byte_io = BytesIO()

image.save(byte_io, 'PNG')

Read more: http://fadeit.dk/blog/post/python3-flask-pil-in-memory-image

Must issue a STARTTLS command first

I also faced the same issue while I was building email notification application. you just need to add one line. Below one saved my day.

props.put("mail.smtp.starttls.enable", "true");

com.sun.mail.smtp.SMTPSendFailedException: 530 5.7.0 Must issue a STARTTLS command first. h13-v6sm10627790pgp.13 - gsmtp

at com.sun.mail.smtp.SMTPTransport.issueSendCommand(SMTPTransport.java:2108)
at com.sun.mail.smtp.SMTPTransport.mailFrom(SMTPTransport.java:1609)
at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:1117)
at javax.mail.Transport.send0(Transport.java:195)
at javax.mail.Transport.send(Transport.java:124)
at com.smruti.email.EmailProject.EmailSend.main(EmailSend.java:99)

Hope this helps you.

Delete with Join in MySQL

I'm more used to the subquery solution to this, but I have not tried it in MySQL:

DELETE  FROM posts
WHERE   project_id IN (
            SELECT  project_id
            FROM    projects
            WHERE   client_id = :client_id
        );

How do I install Python packages on Windows?

I had problems in installing packages on Windows. Found the solution. It works in Windows7+. Mainly anything with Windows Powershell should be able to make it work. This can help you get started with it.

  • Firstly, you'll need to add python installation to your PATH variable. This should help.
  • You need to download the package in zip format that you are trying to install and unzip it. If it is some odd zip format use 7Zip and it should be extracted.
  • Navigate to the directory extracted with setup.py using Windows Powershell (Use link for it if you have problems)
  • Run the command python setup.py install

That worked for me when nothing else was making any sense. I use Python 2.7 but the documentation suggests that same would work for Python 3.x also.

What's the difference setting Embed Interop Types true and false in Visual Studio?

I noticed that when it's set to false, I'm able to see the value of an item using the debugger. When it was set to true, I was getting an error - item.FullName.GetValue The embedded interop type 'FullName' does not contain a definition for 'QBFC11Lib.IItemInventoryRet' since it was not used in the compiled assembly. Consider casting to object or changing the 'Embed Interop Types' property to true.

How to install a specific version of a package with pip?

Use ==:

pip install django_modeltranslation==0.4.0-beta2

Why use pointers?

Because copying big objects all over the places wastes time and memory.

Disable autocomplete via CSS

There are 3 ways to that, i mention them in order of being the better way...

1-HTML way:

<input type="text" autocomplete="false" />

2-Javascript way:

document.getElementById("input-id").getAttribute("autocomplete") = "off";

3-jQuery way:

$('input').attr('autocomplete','off');

Maximum value for long integer

Long integers:

There is no explicitly defined limit. The amount of available address space forms a practical limit.
(Taken from this site). See the docs on Numeric Types where you'll see that Long integers have unlimited precision. In Python 2, Integers will automatically switch to longs when they grow beyond their limit:

>>> import sys
>>> type(sys.maxsize)
<type 'int'>
>>> type(sys.maxsize+1)
<type 'long'>


for integers we have

maxint and maxsize:

The maximum value of an int can be found in Python 2.x with sys.maxint. It was removed in Python 3, but sys.maxsize can often be used instead. From the changelog:

The sys.maxint constant was removed, since there is no longer a limit to the value of integers. However, sys.maxsize can be used as an integer larger than any practical list or string index. It conforms to the implementation’s “natural” integer size and is typically the same as sys.maxint in previous releases on the same platform (assuming the same build options).

and, for anyone interested in the difference (Python 2.x):

sys.maxint The largest positive integer supported by Python’s regular integer type. This is at least 2**31-1. The largest negative integer is -maxint-1 — the asymmetry results from the use of 2’s complement binary arithmetic.

sys.maxsize The largest positive integer supported by the platform’s Py_ssize_t type, and thus the maximum size lists, strings, dicts, and many other containers can have.

and for completeness, here's the Python 3 version:

sys.maxsize An integer giving the maximum value a variable of type Py_ssize_t can take. It’s usually 2^31 - 1 on a 32-bit platform and 2^63 - 1 on a 64-bit platform.

floats:

There's float("inf") and float("-inf"). These can be compared to other numeric types:

>>> import sys
>>> float("inf") > sys.maxsize
True

"No Content-Security-Policy meta tag found." error in my phonegap application

After adding the cordova-plugin-whitelist, you must tell your application to allow access all the web-page links or specific links, if you want to keep it specific.

You can simply add this to your config.xml, which can be found in your application's root directory:

Recommended in the documentation:

<allow-navigation href="http://example.com/*" />

or:

<allow-navigation href="http://*/*" />

From the plugin's documentation:

Navigation Whitelist

Controls which URLs the WebView itself can be navigated to. Applies to top-level navigations only.

Quirks: on Android it also applies to iframes for non-http(s) schemes.

By default, navigations only to file:// URLs, are allowed. To allow other other URLs, you must add tags to your config.xml:

<!-- Allow links to example.com -->
<allow-navigation href="http://example.com/*" />

<!-- Wildcards are allowed for the protocol, as a prefix
     to the host, or as a suffix to the path -->
<allow-navigation href="*://*.example.com/*" />

<!-- A wildcard can be used to whitelist the entire network,
     over HTTP and HTTPS.
     *NOT RECOMMENDED* -->
<allow-navigation href="*" />

<!-- The above is equivalent to these three declarations -->
<allow-navigation href="http://*/*" />
<allow-navigation href="https://*/*" />
<allow-navigation href="data:*" />

How to set iPhone UIView z index?

We can use zPosition in ios

if we have a view named salonDetailView eg : @IBOutlet weak var salonDetailView: UIView!

In my case see the image

and have UIView for GMSMapView eg : @IBOutlet weak var mapViewUI: GMSMapView!

To show the View salonDetailView upper of the mapViewUI

use zPosition as below

salonDetailView.layer.zPosition = 1

How to store images in mysql database using php

insert image zh

-while we insert image in database using insert query

$Image = $_FILES['Image']['name'];
    if(!$Image)
    {
      $Image="";
    }
    else
    {
      $file_path = 'upload/';
      $file_path = $file_path . basename( $_FILES['Image']['name']);    
      if(move_uploaded_file($_FILES['Image']['tmp_name'], $file_path)) 
     { 
}
}

Specifying colClasses in the read.csv

If you want to refer to names from the header rather than column numbers, you can use something like this:

fname <- "test.csv"
headset <- read.csv(fname, header = TRUE, nrows = 10)
classes <- sapply(headset, class)
classes[names(classes) %in% c("time")] <- "character"
dataset <- read.csv(fname, header = TRUE, colClasses = classes)

How do I make a WPF TextBlock show my text on multiple lines?

This gets part way there. There is no ActualFontSize property but there is an ActualHeight and that would relate to the FontSize. Right now this only sizes for the original render. I could not figure out how to register the Converter as resize event. Actually maybe need to register the FontSize as a resize event. Please don't mark me down for an incomplete answer. I could not put code sample in a comment.

    <Window.Resources>
        <local:WidthConverter x:Key="widthConverter"/>
    </Window.Resources>
    <Grid>
        <Grid>
            <StackPanel VerticalAlignment="Center" Orientation="Vertical" >
                <Viewbox Margin="100,0,100,0">
                    <TextBlock x:Name="headerText" Text="Lorem ipsum dolor" Foreground="Black"/>
                </Viewbox>
                <TextBlock Margin="150,0,150,0" FontSize="{Binding ElementName=headerText, Path=ActualHeight, Converter={StaticResource widthConverter}}" x:Name="subHeaderText" Text="Lorem ipsum dolor, Lorem ipsum dolor, lorem isum dolor, Lorem ipsum dolor, Lorem ipsum dolor, lorem isum dolor, " TextWrapping="Wrap" Foreground="Gray" />
            </StackPanel>
        </Grid>
    </Grid>        

Converter

    [ValueConversion(typeof(double), typeof(double))]
    public class WidthConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            double width = (double)value*.7;
            return width; // columnsCount;
        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    } 

jQuery: How to get the HTTP status code from within the $.ajax.error method?

If you're using jQuery 1.5, then statusCode will work.

If you're using jQuery 1.4, try this:

error: function(jqXHR, textStatus, errorThrown) {
    alert(jqXHR.status);
    alert(textStatus);
    alert(errorThrown);
}

You should see the status code from the first alert.

Center an element with "absolute" position and undefined width in CSS?

Flexbox can be used to center an absolute positioned div.

display: flex;
align-items: center;
justify-content: center;

_x000D_
_x000D_
.relative {
  width: 275px;
  height: 200px;
  background: royalblue;
  color: white;
  margin: auto;
  position: relative;
}

.absolute-block {
  position: absolute;
  height: 36px;
  background: orange;
  padding: 0px 10px;
  bottom: -5%;
  border: 1px solid black;
}

.center-text {
  display: flex;
  justify-content: center;
  align-items: center;
  box-shadow: 1px 2px 10px 2px rgba(0, 0, 0, 0.3);
}
_x000D_
<div class="relative center-text">
  Relative Block
  <div class="absolute-block center-text">Absolute Block</div>
</div>
_x000D_
_x000D_
_x000D_

Where is Maven Installed on Ubuntu

Ubuntu 11.10 doesn't have maven3 in repo.

Follow below step to install maven3 on ubuntu 11.10

sudo add-apt-repository ppa:natecarlson/maven3
sudo apt-get update && sudo apt-get install maven3

Open terminal: mvn3 -v

if you want mvn as a binary then execute below script:

sudo ln -s /usr/bin/mvn3 /usr/bin/mvn

I hope this will help you.

Thanks, Rajam

How to have a default option in Angular.js select box

If you have some thing instead of just init the date part, you can use ng-init() by declare it in your controller, and use it in the top of your HTML. This function will work like a constructor for your controller, and you can initiate your variables there.

angular.module('myApp', [])
 .controller('myController', ['$scope', ($scope) => {
   $scope.allOptions = [
     { name: 'Apple', value: 'apple' }, 
     { name: 'Banana', value: 'banana' }
   ];
   $scope.myInit = () => {
      $scope.userSelected = 'apple'
      // Other initiations can goes here..
   }
}]);


<body ng-app="myApp">
  <div ng-controller="myController" ng-init="init()">
    <select ng-model="userSelected" ng-options="option.value as option.name for option in allOptions"></select>
   </div>
</body>

Difference between View and Request scope in managed beans

A @ViewScoped bean lives exactly as long as a JSF view. It usually starts with a fresh new GET request, or with a navigation action, and will then live as long as the enduser submits any POST form in the view to an action method which returns null or void (and thus navigates back to the same view). Once you refresh the page, or return a non-null string (even an empty string!) navigation outcome, then the view scope will end.

A @RequestScoped bean lives exactly as long a HTTP request. It will thus be garbaged by end of every request and recreated on every new request, hereby losing all changed properties.

A @ViewScoped bean is thus particularly more useful in rich Ajax-enabled views which needs to remember the (changed) view state across Ajax requests. A @RequestScoped one would be recreated on every Ajax request and thus fail to remember all changed view state. Note that a @ViewScoped bean does not share any data among different browser tabs/windows in the same session like as a @SessionScoped bean. Every view has its own unique @ViewScoped bean.

See also:

What is let-* in Angular 2 templates?

update Angular 5

ngOutletContext was renamed to ngTemplateOutletContext

See also https://github.com/angular/angular/blob/master/CHANGELOG.md#500-beta5-2017-08-29

original

Templates (<template>, or <ng-template> since 4.x) are added as embedded views and get passed a context.

With let-col the context property $implicit is made available as col within the template for bindings. With let-foo="bar" the context property bar is made available as foo.

For example if you add a template

<ng-template #myTemplate let-col let-foo="bar">
  <div>{{col}}</div>
  <div>{{foo}}</div>
</ng-template>

<!-- render above template with a custom context -->
<ng-template [ngTemplateOutlet]="myTemplate"
             [ngTemplateOutletContext]="{
                                           $implicit: 'some col value',
                                           bar: 'some bar value'
                                        }"
></ng-template>

See also this answer and ViewContainerRef#createEmbeddedView.

*ngFor also works this way. The canonical syntax makes this more obvious

<ng-template ngFor let-item [ngForOf]="items" let-i="index" let-odd="odd">
  <div>{{item}}</div>
</ng-template>

where NgFor adds the template as embedded view to the DOM for each item of items and adds a few values (item, index, odd) to the context.

See also Using $implict to pass multiple parameters

Exchange Powershell - How to invoke Exchange 2010 module from inside script?

I know this is an old question, but rather than adding the snapin which is apparently unsupported, I just looked at the EMS shortcut properties and copied those commands.

The full shortcut target is:

C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe -noexit -command ". 'C:\Program Files\Microsoft\Exchange Server\V14\bin\RemoteExchange.ps1'; Connect-ExchangeServer -auto"

So I put the following at the start of my script and it seemed to function as expected:

. 'C:\Program Files\Microsoft\Exchange Server\V14\bin\RemoteExchange.ps1'
Connect-ExchangeServer -auto

Notes:

  • Has to be run in 64bit PS
  • This was tested on a server with just the Management Tools installed. It automatically connected to our existing Exchange infrastructure.
  • No extensive testing has been done, so I do not know if this method is viable. I will edit this post if I run into any issues.

React-router: How to manually invoke Link?

React Router v5 - React 16.8+ with Hooks (updated 09/23/2020)

If you're leveraging React Hooks, you can take advantage of the useHistory API that comes from React Router v5.

import React, {useCallback} from 'react';
import {useHistory} from 'react-router-dom';

export default function StackOverflowExample() {
  const history = useHistory();
  const handleOnClick = useCallback(() => history.push('/sample'), [history]);

  return (
    <button type="button" onClick={handleOnClick}>
      Go home
    </button>
  );
}

Another way to write the click handler if you don't want to use useCallback

const handleOnClick = () => history.push('/sample');

React Router v4 - Redirect Component

The v4 recommended way is to allow your render method to catch a redirect. Use state or props to determine if the redirect component needs to be shown (which then trigger's a redirect).

import { Redirect } from 'react-router';

// ... your class implementation

handleOnClick = () => {
  // some action...
  // then redirect
  this.setState({redirect: true});
}

render() {
  if (this.state.redirect) {
    return <Redirect push to="/sample" />;
  }

  return <button onClick={this.handleOnClick} type="button">Button</button>;
}

Reference: https://reacttraining.com/react-router/web/api/Redirect

React Router v4 - Reference Router Context

You can also take advantage of Router's context that's exposed to the React component.

static contextTypes = {
  router: PropTypes.shape({
    history: PropTypes.shape({
      push: PropTypes.func.isRequired,
      replace: PropTypes.func.isRequired
    }).isRequired,
    staticContext: PropTypes.object
  }).isRequired
};

handleOnClick = () => {
  this.context.router.push('/sample');
}

This is how <Redirect /> works under the hood.

Reference: https://github.com/ReactTraining/react-router/blob/master/packages/react-router/modules/Redirect.js#L46,L60

React Router v4 - Externally Mutate History Object

If you still need to do something similar to v2's implementation, you can create a copy of BrowserRouter then expose the history as an exportable constant. Below is a basic example but you can compose it to inject it with customizable props if needed. There are noted caveats with lifecycles, but it should always rerender the Router, just like in v2. This can be useful for redirects after an API request from an action function.

// browser router file...
import createHistory from 'history/createBrowserHistory';
import { Router } from 'react-router';

export const history = createHistory();

export default class BrowserRouter extends Component {
  render() {
    return <Router history={history} children={this.props.children} />
  }
}

// your main file...
import BrowserRouter from './relative/path/to/BrowserRouter';
import { render } from 'react-dom';

render(
  <BrowserRouter>
    <App/>
  </BrowserRouter>
);

// some file... where you don't have React instance references
import { history } from './relative/path/to/BrowserRouter';

history.push('/sample');

Latest BrowserRouter to extend: https://github.com/ReactTraining/react-router/blob/master/packages/react-router-dom/modules/BrowserRouter.js

React Router v2

Push a new state to the browserHistory instance:

import {browserHistory} from 'react-router';
// ...
browserHistory.push('/sample');

Reference: https://github.com/reactjs/react-router/blob/master/docs/guides/NavigatingOutsideOfComponents.md

Trim last 3 characters of a line WITHOUT using sed, or perl, etc

Note: This answer is somewhat intended to be a joke, but it actually does work...

#!/bin/bash
outfile="/tmp/$RANDOM"
cfile="$outfile.c"
echo '#include <stdio.h>
int main(void){int e=1;char c;while((c=getc(stdin))!=-1){if(c==10)e=1;if(c==32)e=0;if(e)putc(c,stdout);}}' >> "$cfile"
gcc -o "$outfile" "$cfile"
rm "$cfile"
cat somedata.txt | "$outfile"
rm "$outfile"

You can replace cat somedata.txt with a different command.

Where/how can I download (and install) the Microsoft.Jet.OLEDB.4.0 for Windows 8, 64 bit?

On modern Windows this driver isn't available by default anymore, but you can download as Microsoft Access Database Engine 2010 Redistributable on the MS site. If your app is 32 bits be sure to download and install the 32 bits variant because to my knowledge the 32 and 64 bit variant cannot coexist.

Depending on how your app locates its db driver, that might be all that's needed. However, if you use an UDL file there's one extra step - you need to edit that file. Unfortunately, on a 64bits machine the wizard used to edit UDL files is 64 bits by default, it won't see the JET driver and just slap whatever driver it finds first in the UDL file. There are 2 ways to solve this issue:

  1. start the 32 bits UDL wizard like this: C:\Windows\syswow64\rundll32.exe "C:\Program Files (x86)\Common Files\System\Ole DB\oledb32.dll",OpenDSLFile C:\path\to\your.udl. Note that I could use this technique on a Win7 64 Pro, but it didn't work on a Server 2008R2 (could be my mistake, just mentioning)
  2. open the UDL file in Notepad or another text editor, it should more or less have this format:

[oledb] ; Everything after this line is an OLE DB initstring Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\Path\To\The\database.mdb;Persist Security Info=False

That should allow your app to start correctly.

How to change content on hover

This little and simple trick I just learnt may help someone trying to avoid :before or :after pseudo elements altogether (for whatever reason) in changing text on hover. You can add both texts in the HTML, but vary the CSS 'display' property based on hover. Assuming the second text 'Add' has a class named 'add-label'; here is a little modification:

span.add-label{
 display:none;
}
.item:hover span.align{
 display:none;
}
.item:hover span.add-label{
 display:block;
}

Here is a demonstration on codepen: https://codepen.io/ifekt/pen/zBaEVJ

Scroll RecyclerView to show selected item on top

same with speed regulator

public class SmoothScrollLinearLayoutManager extends LinearLayoutManager {
private static final float MILLISECONDS_PER_INCH = 110f;
private Context mContext;

public SmoothScrollLinearLayoutManager(Context context,int orientation, boolean reverseLayout) {
    super(context,orientation,reverseLayout);
    mContext = context;
}

@Override
public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state,
                                   int position) {
    RecyclerView.SmoothScroller smoothScroller = new TopSnappedSmoothScroller(recyclerView.getContext()){
        //This controls the direction in which smoothScroll looks for your view
        @Override
        public PointF computeScrollVectorForPosition(int targetPosition) {
            return new PointF(0, 1);
        }

        //This returns the milliseconds it takes to scroll one pixel.
        @Override
        protected float calculateSpeedPerPixel(DisplayMetrics displayMetrics) {
            return MILLISECONDS_PER_INCH / displayMetrics.densityDpi;
        }
    };
    smoothScroller.setTargetPosition(position);
    startSmoothScroll(smoothScroller);
}


private class TopSnappedSmoothScroller extends LinearSmoothScroller {
    public TopSnappedSmoothScroller(Context context) {
        super(context);

    }

    @Override
    public PointF computeScrollVectorForPosition(int targetPosition) {
        return SmoothScrollLinearLayoutManager.this
                .computeScrollVectorForPosition(targetPosition);
    }

    @Override
    protected int getVerticalSnapPreference() {
        return SNAP_TO_START;
    }
}
}

What are the uses of the exec command in shell scripts?

Just to augment the accepted answer with a brief newbie-friendly short answer, you probably don't need exec.

If you're still here, the following discussion should hopefully reveal why. When you run, say,

sh -c 'command'

you run a sh instance, then start command as a child of that sh instance. When command finishes, the sh instance also finishes.

sh -c 'exec command'

runs a sh instance, then replaces that sh instance with the command binary, and runs that instead.

Of course, both of these are useless in this limited context; you simply want

command

There are some fringe situations where you want the shell to read its configuration file or somehow otherwise set up the environment as a preparation for running command. This is pretty much the sole situation where exec command is useful.

#!/bin/sh
ENVIRONMENT=$(some complex task)
exec command

This does some stuff to prepare the environment so that it contains what is needed. Once that's done, the sh instance is no longer necessary, and so it's a (minor) optimization to simply replace the sh instance with the command process, rather than have sh run it as a child process and wait for it, then exit as soon as it finishes.

Similarly, if you want to free up as much resources as possible for a heavyish command at the end of a shell script, you might want to exec that command as an optimization.

If something forces you to run sh but you really wanted to run something else, exec something else is of course a workaround to replace the undesired sh instance (like for example if you really wanted to run your own spiffy gosh instead of sh but yours isn't listed in /etc/shells so you can't specify it as your login shell).

The second use of exec to manipulate file descriptors is a separate topic. The accepted answer covers that nicely; to keep this self-contained, I'll just defer to the manual for anything where exec is followed by a redirect instead of a command name.

"psql: could not connect to server: Connection refused" Error when connecting to remote database

I have struggled with this when trying to remotely connect to a new PostgreSQL installation on my Raspberry Pi. Here's the full breakdown of what I did to resolve this issue:

First, open the PostgreSQL configuration file and make sure that the service is going to listen outside of localhost.

sudo [editor] /etc/postgresql/[version]/main/postgresql.conf

I used nano, but you can use the editor of your choice, and while I have version 9.1 installed, that directory will be for whichever version you have installed.

Search down to the section titled 'Connections and Authentication'. The first setting should be 'listen_addresses', and might look like this:

#listen_addresses = 'localhost'     # what IP address(es) to listen on;

The comments to the right give good instructions on how to change this field, and using the suggested '*' for all will work well.

Please note that this field is commented out with #. Per the comments, it will default to 'localhost', so just changing the value to '*' isn't enough, you also need to uncomment the setting by removing the leading #.

It should now look like this:

listen_addresses = '*'         # what IP address(es) to listen on;

You can also check the next setting, 'port', to make sure that you're connecting correctly. 5432 is the default, and is the port that psql will try to connect to if you don't specify one.

Save and close the file, then open the Client Authentication config file, which is in the same directory:

sudo [editor] /etc/postgresql/[version]/main/pg_hba.conf

I recommend reading the file if you want to restrict access, but for basic open connections you'll jump to the bottom of the file and add a line like this:

host all all all md5

You can press tab instead of space to line the fields up with the existing columns if you like.

Personally, I instead added a row that looked like this:

host [database_name] pi 192.168.1.0/24 md5

This restricts the connection to just the one user and just the one database on the local area network subnet.

Once you've saved changes to the file you will need to restart the service to implement the changes.

sudo service postgresql restart

Now you can check to make sure that the service is openly listening on the correct port by using the following command:

sudo netstat -ltpn

If you don't run it as elevated (using sudo) it doesn't tell you the names of the processes listening on those ports.

One of the processes should be Postgres, and the Local Address should be open (0.0.0.0) and not restricted to local traffic only (127.0.0.1). If it isn't open, then you'll need to double check your config files and restart the service. You can again confirm that the service is listening on the correct port (default is 5432, but your configuration could be different).

Finally you'll be able to successfully connect from a remote computer using the command:

psql -h [server ip address] -p [port number, optional if 5432] -U [postgres user name] [database name]

set dropdown value by text using jquery

$("#HowYouKnow").val("GOOGLE");

How do I call an Angular.js filter with multiple arguments?

If you want to call your filter inside ng-options the code will be as follows:

ng-options="productSize as ( productSize | sizeWithPrice: product )  for productSize in productSizes track by productSize.id"

where the filter is sizeWithPriceFilter and it has two parameters product and productSize

Multiple inputs on one line

Yes, you can.

From cplusplus.com:

Because these functions are operator overloading functions, the usual way in which they are called is:

   strm >> variable;

Where strm is the identifier of a istream object and variable is an object of any type supported as right parameter. It is also possible to call a succession of extraction operations as:

   strm >> variable1 >> variable2 >> variable3; //...

which is the same as performing successive extractions from the same object strm.

Just replace strm with cin.

Is it necessary to assign a string to a variable before comparing it to another?

Brian, also worth throwing in here - the others are of course correct that you don't need to declare a string variable. However, next time you want to declare a string you don't need to do the following:

NSString *myString = [[NSString alloc] initWithFormat:@"SomeText"];

Although the above does work, it provides a retained NSString variable which you will then need to explicitly release after you've finished using it.

Next time you want a string variable you can use the "@" symbol in a much more convenient way:

NSString *myString = @"SomeText";

This will be autoreleased when you've finished with it so you'll avoid memory leaks too...

Hope that helps!

Error - is not marked as serializable

You need to add a Serializable attribute to the class which you want to serialize.

[Serializable]
public class OrgPermission

Adding open/closed icon to Twitter Bootstrap collapsibles (accordions)

A bootstrap v3 solution (where the events have different names), also using only one jQuery selector (as seen here):

$('.accordion').on('hide.bs.collapse show.bs.collapse', function (n) {
    $(n.target).siblings('.panel-heading').find('i.glyphicon').toggleClass('glyphicon-chevron-down glyphicon-chevron-up');
});

iPhone - Grand Central Dispatch main thread

Dispatching blocks to the main queue from the main thread can be useful. It gives the main queue a chance to handle other blocks that have been queued so that you're not simply blocking everything else from executing.

For example you could write an essentially single threaded server that nonetheless handles many concurrent connections. As long as no individual block in the queue takes too long the server stays responsive to new requests.

If your program does nothing but spend its whole life responding to events then this can be quite natural. You just set up your event handlers to run on the main queue and then call dispatch_main(), and you may not need to worry about thread safety at all.

How to run Maven from another directory (without cd to project dir)?

You can try this:

pushd ../
maven install [...]
popd

What do >> and << mean in Python?

The other case involving print >>obj, "Hello World" is the "print chevron" syntax for the print statement in Python 2 (removed in Python 3, replaced by the file argument of the print() function). Instead of writing to standard output, the output is passed to the obj.write() method. A typical example would be file objects having a write() method. See the answer to a more recent question: Double greater-than sign in Python.

How to generate sample XML documents from their DTD or XSD?

XML Blueprint also does that; instructions here

http://www.xmlblueprint.com/help/html/topic_170.htm

It's not free, but there's a 10-day free trial; it seems fast and efficient; unfortunately it's Windows only.

browser sessionStorage. share between tabs?

  1. You can just use localStorage and remember the date it was first created in session cookie. When localStorage "session" is older than the value of cookie then you may clear the localStorage

    Cons of this is that someone can still read the data after the browser is closed so it's not a good solution if your data is private and confidental.

  2. You can store your data to localStorage for a couple of seconds and add event listener for a storage event. This way you will know when any of the tabs wrote something to the localStorage and you can copy its content to the sessionStorage, then just clear the localStorage

How to use patterns in a case statement?

I don't think you can use braces.

According to the Bash manual about case in Conditional Constructs.

Each pattern undergoes tilde expansion, parameter expansion, command substitution, and arithmetic expansion.

Nothing about Brace Expansion unfortunately.

So you'd have to do something like this:

case $1 in
    req*)
        ...
        ;;
    met*|meet*)
        ...
        ;;
    *)
        # You should have a default one too.
esac

create multiple tag docker image

You can't create tags with Dockerfiles but you can create multiple tags on your images via the command line.

Use this to list your image ids:

$ docker images

Then tag away:

$ docker tag 9f676bd305a4 ubuntu:13.10
$ docker tag 9f676bd305a4 ubuntu:saucy
$ docker tag eb601b8965b8 ubuntu:raring
...

How to determine the IP address of a Solaris system

Try using ifconfig -a. Look for "inet xxx.xxx.xxx.xxx", that is your IP address

Eclipse not recognizing JVM 1.8

Echoing the answer, above, a full install of the JDK (8u121 at this writing) from here - http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html - did the trick. Updating via the Mac OS Control Panel did not update the profile variable. Installing via the full installer, did. Then Eclipse was happy.

Is log(n!) = T(n·log(n))?

Remember that

log(n!) = log(1) + log(2) + ... + log(n-1) + log(n)

You can get the upper bound by

log(1) + log(2) + ... + log(n) <= log(n) + log(n) + ... + log(n)
                                = n*log(n)

And you can get the lower bound by doing a similar thing after throwing away the first half of the sum:

log(1) + ... + log(n/2) + ... + log(n) >= log(n/2) + ... + log(n) 
                                       = log(n/2) + log(n/2+1) + ... + log(n-1) + log(n)
                                       >= log(n/2) + ... + log(n/2)
                                        = n/2 * log(n/2) 

Attempt by security transparent method 'WebMatrix.WebData.PreApplicationStartCode.Start()'

I installed webapi with it via the helppages nuget package. That package replaced most of the asp.net mvc 4 binaries with beta versions which didn't work well together with the rest of the project. Fix was to restore the original mvc 4 dll's and all was good.

What are "res" and "req" parameters in Express functions?

I noticed one error in Dave Ward's answer (perhaps a recent change?): The query string paramaters are in request.query, not request.params. (See https://stackoverflow.com/a/6913287/166530 )

request.params by default is filled with the value of any "component matches" in routes, i.e.

app.get('/user/:id', function(request, response){
  response.send('user ' + request.params.id);
});

and, if you have configured express to use its bodyparser (app.use(express.bodyParser());) also with POST'ed formdata. (See How to retrieve POST query parameters? )

Positioning background image, adding padding

In case anyone else needs to add padding to something with background-image and background-size: contain or cover, I used the following which is a nice way of doing it. You can replace the border-width with 10% or 2vw or whatever you like.

.bg-image {
    background: url("/image/logo.png") no-repeat center #ffffff / contain;
    border: inset 10px transparent;
    box-sizing: border-box;
}

This means you don't have to define a width.

'method' object is not subscriptable. Don't know what's wrong

You need to use parentheses: myList.insert([1, 2, 3]). When you leave out the parentheses, python thinks you are trying to access myList.insert at position 1, 2, 3, because that's what brackets are used for when they are right next to a variable.

Check if a class `active` exist on element with jquery

Pure JavaScript answer:

document.querySelector('.menu').classList.contains('active');

Might help someone someday.

Internet Explorer 11- issue with security certificate error prompt

This behavior is related to Zone that is set - Internet/Intranet/etc and corresponding Security Level

You can change this by setting less secure Security Level (not recommended) or by customizing Display Mixed Content property

You can do that by following steps:

  1. Click on Gear icon at the top of the browser window.
  2. Select Internet Options.
  3. Select the Security tab at the top.
  4. Click the Custom Level... button.
  5. Scroll about halfway down to the Miscellaneous heading (denoted by a "blank page" icon).
  6. Under this heading is the option Display Mixed Content; set this to Enable/Prompt.
  7. Click OK, then Yes when prompted to confirm the change, then OK to close the Options window.
  8. Close and restart the browser.

enter image description here

Maven error: Could not find or load main class org.codehaus.plexus.classworlds.launcher.Launcher

This worked for me:

  1. Remove all Mavin references in Environment Variables
  2. Download the Binary from mavin
  3. Unzip it to where you'd like ex: C:\apache-maven-3.6.0
  4. Go to Environment variables and add to System variable path "C:\apache-maven-3.6.0\bin"
  5. start command prompt as Administrator
  6. check version with: mvn -v

CMD Result:

Apache Maven 3.6.0 (97c98ec64a1fdfee7767ce5ffb20918da4f719f3; 2018-10-24T20:41:47+02:00) Maven home: C:\apache-maven-3.6.0\bin..

lists and arrays in VBA

You will have to change some of your data types but the basics of what you just posted could be converted to something similar to this given the data types I used may not be accurate.

Dim DateToday As String: DateToday = Format(Date, "yyyy/MM/dd")
Dim Computers As New Collection
Dim disabledList As New Collection
Dim compArray(1 To 1) As String

'Assign data to first item in array
compArray(1) = "asdf"

'Format = Item, Key
Computers.Add "ErrorState", "Computer Name"

'Prints "ErrorState"
Debug.Print Computers("Computer Name")

Collections cannot be sorted so if you need to sort data you will probably want to use an array.

Here is a link to the outlook developer reference. http://msdn.microsoft.com/en-us/library/office/ff866465%28v=office.14%29.aspx

Another great site to help you get started is http://www.cpearson.com/Excel/Topic.aspx

Moving everything over to VBA from VB.Net is not going to be simple since not all the data types are the same and you do not have the .Net framework. If you get stuck just post the code you're stuck converting and you will surely get some help!

Edit:

Sub ArrayExample()
    Dim subject As String
    Dim TestArray() As String
    Dim counter As Long

    subject = "Example"
    counter = Len(subject)

    ReDim TestArray(1 To counter) As String

    For counter = 1 To Len(subject)
        TestArray(counter) = Right(Left(subject, counter), 1)
    Next
End Sub

XML Error: There are multiple root elements

You can do it without modifying the XML stream: Tell the XmlReader to not be so picky. Setting the XmlReaderSettings.ConformanceLevel to ConformanceLevel.Fragment will let the parser ignore the fact that there is no root node.

        XmlReaderSettings settings = new XmlReaderSettings();
        settings.ConformanceLevel = ConformanceLevel.Fragment;
        using (XmlReader reader = XmlReader.Create(tr,settings))
        {
             ...
        }

Now you can parse something like this (which is an real time XML stream, where it is impossible to wrap with a node).

<event>
  <timeStamp>1354902435238</timeStamp>
  <eventId>7073822</eventId>
</event>
<data>
  <time>1354902435341</time>
  <payload type='80'>7d1300786a0000000bf9458b0518000000000000000000000000000000000c0c030306001b</payload>
</data>
<data>
  <time>1354902435345</time>
  <payload type='80'>fd1260780912ff3028fea5ffc0387d640fa550f40fbdf7afffe001fff8200fff00f0bf0e000042201421100224ff40312300111400004f000000e0c0fbd1e0000f10e0fccc2ff0000f0fe00f00f0eed00f11e10d010021420401</payload>
</data>
<data>
  <time>1354902435347</time>
  <payload type='80'>fd126078ad11fc4015fefdf5b042ff1010223500000000000000003007ff00f20e0f01000e0000dc0f01000f000000000000004f000000f104ff001000210f000013010000c6da000000680ffa807800200000000d00c0f0</payload>
</data>

Differences between "java -cp" and "java -jar"?

Like already said, the -cp is just for telling the jvm in the command line which class to use for the main thread and where it can find the libraries (define classpath). In -jar it expects the class-path and main-class to be defined in the jar file manifest. So other is for defining things in command line while other finding them inside the jar manifest. There is no difference in performance. You can't use them at the same time, -jar will override the -cp.

Though even if you use -cp, it will still check the manifest file. So you can define some of the class-paths in the manifest and some in the command line. This is particularly useful when you have a dependency on some 3rd party jar, which you might not provide with your build or don't want to provide (expecting it to be found already in the system where it's to be installed for example). So you can use it to provide external jars. It's location may vary between systems or it may even have a different version on different system (but having the same interfaces). This way you can build the app with other version and add the actual 3rd party dependency to class-path on the command line when running it on different systems.

How to keep a VMWare VM's clock in sync?

I'll answer for Windows guests. If you have VMware Tools installed, then the taskbar's notification area (near the clock) has an icon for VMware Tools. Double-click that and set your options.

If you don't have VMware Tools installed, you can still set the clock's option for internet time to sync with some NTP server. If your physical machine serves the NTP protocol to your guest machines then you can get that done with host-only networking. Otherwise you'll have to let your guests sync with a genuine NTP server out on the internet, for example time.windows.com.

Visual Studio 2015 is very slow

It is most likely because you uninstalled some SQL Server components Visual Studio is using. Though Visual Studio still works, it's very slow.

Just go to "Programs and Features" in the Control Panel and repair Visual Studio. The needed Visual Studio components will be installed again and Visual Studio will be back as fast as before.

How do I get a PHP class constructor to call its parent's parent's constructor?

<?php

class grand_pa
{
    public function __construct()
    {
        echo "Hey I am Grand Pa <br>";
    }
}

class pa_pa extends grand_pa
{
    // no need for construct here unless you want to do something specifically within this class as init stuff
    // the construct for this class will be inherited from the parent.
}

class kiddo extends pa_pa
{
    public function __construct()
    {
        parent::__construct();
        echo "Hey I am a child <br>";
    }
}

new kiddo();
?>

Of course this expects you do not need to do anything within the construct of the pa_pa. Running this will output :

Hey I am Grand Pa Hey I am a child

Export table to file with column headers (column names) using the bcp utility and SQL Server 2008

With a little PowerShell script:

_x000D_
_x000D_
sqlcmd -Q "set nocount on select top 0 * from [DB].[schema].[table]" -o c:\temp\header.txt_x000D_
bcp [DB].[schema].[table] out c:\temp\query.txt -c -T -S BRIZA_x000D_
Get-Content c:\temp\*.txt | Set-Content c:\temp\result.txt_x000D_
Remove-Item c:\temp\header.txt_x000D_
Remove-Item c:\temp\query.txt
_x000D_
_x000D_
_x000D_

Warning: The concatenation follows the .txt file name (in alphabetical order)

How to load up CSS files using Javascript?

Have you ever heard of Promises? They work on all modern browsers and are relatively simple to use. Have a look at this simple method to inject css to the html head:

function loadStyle(src) {
    return new Promise(function (resolve, reject) {
        let link = document.createElement('link');
        link.href = src;
        link.rel = 'stylesheet';

        link.onload = () => resolve(link);
        link.onerror = () => reject(new Error(`Style load error for ${src}`));

        document.head.append(link);
    });
}

You can implement it as follows:

window.onload = function () {
    loadStyle("https://fonts.googleapis.com/css2?family=Raleway&display=swap")
        .then(() => loadStyle("css/style.css"))
        .then(() => loadStyle("css/icomoon.css"))
        .then(() => {
            alert('All styles are loaded!');
        }).catch(err => alert(err));
}

It's really cool, right? This is a way to decide the priority of the styles using Promises.

To see a multi-style loading implementation see: https://stackoverflow.com/a/63936671/13720928

Angular HttpClient "Http failure during parsing"

I had the same problem and the cause was That at time of returning a string in your backend (spring) you might be returning as return "spring used"; But this isn't parsed right according to spring. Instead use return "\" spring used \""; -Peace out

How to initialize an array of objects in Java

Arrays are not changeable after initialization. You have to give it a value, and that value is what that array length stays. You can create multiple arrays to contain certain parts of player information like their hand and such, and then create an arrayList to sort of shepherd those arrays.

Another point of contention I see, and I may be wrong about this, is the fact that your private Player[] InitializePlayers() is static where the class is now non-static. So:

private Player[] InitializePlayers(int playerCount)
{
 ...
}

My last point would be that you should probably have playerCount declared outside of the method that is going to change it so that the value that is set to it becomes the new value as well and it is not just tossed away at the end of the method's "scope."

Hope this helps

ORA-01830: date format picture ends before converting entire input string / Select sum where date query

You can try as follows it works for me

select * from nm_admission where trunc(entry_timestamp) = to_date('09-SEP-2018','DD-MM-YY');

OR

select * from nm_admission where trunc(entry_timestamp) = '09-SEP-2018';

You can also try using to_char but remember to_char is too expensive

select * from nm_admission where to_char(entry_timestamp) = to_date('09-SEP-2018','DD-MM-YY');

The TRUNC(17-SEP-2018 08:30:11) will give 17-SEP-2018 00:00:00 as a result, you can compare the only date portion independently and time portion will skip.

How to sort by dates excel?

Here are the steps to convert the entire column to date format values.

Add a column to the right of the date column. Right click the new column and select Format. Set the format to date.

Highlight the entire old date column and copy it. Highlight the top cell of the new column and select Paste Special, and only paste values.

You can then remove the old column.

C++ error: "Array must be initialized with a brace enclosed initializer"

You cannot initialize an array to '0' like that

int cipher[Array_size][Array_size]=0;

You can either initialize all the values in the array as you declare it like this:

// When using different values
int a[3] = {10,20,30};

// When using the same value for all members
int a[3] = {0};

// When using same value for all members in a 2D array
int a[Array_size][Array_size] = { { 0 } };

Or you need to initialize the values after declaration. If you want to initialize all values to 0 for example, you could do something like:

for (int i = 0; i < Array_size; i++ ) {
    a[i] = 0;
}

How to get JSON from webpage into Python script

There's no need to use an extra library to parse the json...

json.loads() returns a dictionary.

So in your case, just do text["someValueKey"]

SQL Server - SELECT FROM stored procedure

For the sake of simplicity and to make it re-runnable, I have used a system StoredProcedure "sp_readerrorlog" to get data:

-----USING Table Variable
DECLARE @tblVar TABLE (
   LogDate DATETIME,
   ProcessInfo NVARCHAR(MAX),
   [Text] NVARCHAR(MAX)
)
INSERT INTO @tblVar Exec sp_readerrorlog
SELECT LogDate as DateOccured, ProcessInfo as pInfo, [Text] as Message FROM @tblVar



-----(OR): Using Temp Table
IF OBJECT_ID('tempdb..#temp') IS NOT NULL  DROP TABLE #temp;
CREATE TABLE #temp (
   LogDate DATETIME,
   ProcessInfo NVARCHAR(55),
   Text NVARCHAR(MAX)
)
INSERT INTO #temp EXEC sp_readerrorlog
SELECT * FROM #temp

Laravel - Forbidden You don't have permission to access / on this server

On public/.htaccess edit to

<IfModule mod_rewrite.c>
 <IfModule mod_negotiation.c>
              Options -MultiViews
          </IfModule>

          RewriteEngine On

          # Redirect Trailing Slashes If Not A Folder...
          RewriteCond %{REQUEST_FILENAME} !-d
          RewriteCond %{REQUEST_URI} (.+)/$
          RewriteRule ^ %1 [L,R=301]

          # Handle Front Controller...
          RewriteCond %{REQUEST_FILENAME} !-d
          RewriteCond %{REQUEST_FILENAME} !-f
          RewriteRule ^ index.php [L]

          # Handle Authorization Header
          RewriteCond %{HTTP:Authorization} .
          RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
</IfModule>

In the root of the project add file

Procfile

File content

web: vendor/bin/heroku-php-apache2 public/

Reload the project to Heroku

bash
heroku login
cd my-project/
git init
heroku git:remote -a my project
git add .
git commit -am "make it better"
git push heroku master
heroku open

MySQL - Trigger for updating same table after insert

Had the same problem but had to update a column with the id that was about to enter, so you can make an update should be done BEFORE and AFTER not BEFORE had no id so I did this trick

DELIMITER $$
DROP TRIGGER IF EXISTS `codigo_video`$$
CREATE TRIGGER `codigo_video` BEFORE INSERT ON `videos` 
FOR EACH ROW BEGIN
    DECLARE ultimo_id, proximo_id INT(11);
    SELECT id INTO ultimo_id FROM videos ORDER BY id DESC LIMIT 1;
    SET proximo_id = ultimo_id+1;
    SET NEW.cassette = CONCAT(NEW.cassette, LPAD(proximo_id, 5, '0'));
END$$
DELIMITER ;

ImportError: No module named win32com.client

I realize this post is old but I wanted to add that I had to take an extra step to get this to work.

Instead of just doing:

pip install pywin32

I had use use the -m flag to get this to work properly. Without it I was running into an issue where I was still getting the error ImportError: No module named win32com.

So to fix this you can give this a try:

python -m pip install pywin32

This worked for me and has worked on several version of python where just doing pip install pywin32 did not work.

Versions tested on:

3.6.2, 3.7.6, 3.8.0, 3.9.0a1.

How to run bootRun with spring profile via gradle task

For those folks using Spring Boot 2.0+, you can use the following to setup a task that will run the app with a given set of profiles.

task bootRunDev(type: org.springframework.boot.gradle.tasks.run.BootRun, dependsOn: 'build') {
    group = 'Application'

    doFirst() {
        main = bootJar.mainClassName
        classpath = sourceSets.main.runtimeClasspath
        systemProperty 'spring.profiles.active', 'dev'
    }
}

Then you can simply run ./gradlew bootRunDev or similar from your IDE.

Show hidden div on ng-click within ng-repeat

Remove the display:none, and use ng-show instead:

<ul class="procedures">
    <li ng-repeat="procedure in procedures | filter:query | orderBy:orderProp">
        <h4><a href="#" ng-click="showDetails = ! showDetails">{{procedure.definition}}</a></h4>
         <div class="procedure-details" ng-show="showDetails">
            <p>Number of patient discharges: {{procedure.discharges}}</p>
            <p>Average amount covered by Medicare: {{procedure.covered}}</p>
            <p>Average total payments: {{procedure.payments}}</p>
         </div>
    </li>
</ul>

Here's the fiddle: http://jsfiddle.net/asmKj/


You can also use ng-class to toggle a class:

<div class="procedure-details" ng-class="{ 'hidden': ! showDetails }">

I like this more, since it allows you to do some nice transitions: http://jsfiddle.net/asmKj/1/

Sass Nesting for :hover does not work

You can easily debug such things when you go through the generated CSS. In this case the pseudo-selector after conversion has to be attached to the class. Which is not the case. Use "&".

http://sass-lang.com/documentation/file.SASS_REFERENCE.html#parent-selector

.class {
    margin:20px;
    &:hover {
        color:yellow;
    }
}

Databound drop down list - initial value

I think what you want to do is this:

<asp:DropDownList ID="DropDownList1" runat="server" AppendDataBoundItems="true">
    <asp:ListItem Text="--Select One--" Value="" />   
</asp:DropDownList>

Make sure the 'AppendDataBoundItems' is set to true or else you will clear the '--Select One--' list item when you bind your data.

If you have the 'AutoPostBack' property of the drop down list set to true you will have to also set the 'CausesValidation' property to true then use a 'RequiredFieldValidator' to make sure the '--Select One--' option doesn't cause a postback.

<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="DropDownList1"></asp:RequiredFieldValidator>

What is a word boundary in regex, does \b match hyphen '-'?

I ran into an even worse problem when searching text for words like .NET, C++, C#, and C. You would think that computer programmers would know better than to name a language something that is hard to write regular expressions for.

Anyway, this is what I found out (summarized mostly from http://www.regular-expressions.info, which is a great site): In most flavors of regex, characters that are matched by the short-hand character class \w are the characters that are treated as word characters by word boundaries. Java is an exception. Java supports Unicode for \b but not for \w. (I'm sure there was a good reason for it at the time).

The \w stands for "word character". It always matches the ASCII characters [A-Za-z0-9_]. Notice the inclusion of the underscore and digits (but not dash!). In most flavors that support Unicode, \w includes many characters from other scripts. There is a lot of inconsistency about which characters are actually included. Letters and digits from alphabetic scripts and ideographs are generally included. Connector punctuation other than the underscore and numeric symbols that aren't digits may or may not be included. XML Schema and XPath even include all symbols in \w. But Java, JavaScript, and PCRE match only ASCII characters with \w.

Which is why Java-based regex searches for C++, C# or .NET (even when you remember to escape the period and pluses) are screwed by the \b.

Note: I'm not sure what to do about mistakes in text, like when someone doesn't put a space after a period at the end of a sentence. I allowed for it, but I'm not sure that it's necessarily the right thing to do.

Anyway, in Java, if you're searching text for the those weird-named languages, you need to replace the \b with before and after whitespace and punctuation designators. For example:

public static String grep(String regexp, String multiLineStringToSearch) {
    String result = "";
    String[] lines = multiLineStringToSearch.split("\\n");
    Pattern pattern = Pattern.compile(regexp);
    for (String line : lines) {
        Matcher matcher = pattern.matcher(line);
        if (matcher.find()) {
            result = result + "\n" + line;
        }
    }
    return result.trim();
}

Then in your test or main function:

    String beforeWord = "(\\s|\\.|\\,|\\!|\\?|\\(|\\)|\\'|\\\"|^)";   
    String afterWord =  "(\\s|\\.|\\,|\\!|\\?|\\(|\\)|\\'|\\\"|$)";
    text = "Programming in C, (C++) C#, Java, and .NET.";
    System.out.println("text="+text);
    // Here is where Java word boundaries do not work correctly on "cutesy" computer language names.  
    System.out.println("Bad word boundary can't find because of Java: grep with word boundary for .NET="+ grep("\\b\\.NET\\b", text));
    System.out.println("Should find: grep exactly for .NET="+ grep(beforeWord+"\\.NET"+afterWord, text));
    System.out.println("Bad word boundary can't find because of Java: grep with word boundary for C#="+ grep("\\bC#\\b", text));
    System.out.println("Should find: grep exactly for C#="+ grep("C#"+afterWord, text));
    System.out.println("Bad word boundary can't find because of Java:grep with word boundary for C++="+ grep("\\bC\\+\\+\\b", text));
    System.out.println("Should find: grep exactly for C++="+ grep(beforeWord+"C\\+\\+"+afterWord, text));

    System.out.println("Should find: grep with word boundary for Java="+ grep("\\bJava\\b", text));
    System.out.println("Should find: grep for case-insensitive java="+ grep("?i)\\bjava\\b", text));
    System.out.println("Should find: grep with word boundary for C="+ grep("\\bC\\b", text));  // Works Ok for this example, but see below
    // Because of the stupid too-short cutsey name, searches find stuff it shouldn't.
    text = "Worked on C&O (Chesapeake and Ohio) Canal when I was younger; more recently developed in Lisp.";
    System.out.println("text="+text);
    System.out.println("Bad word boundary because of C name: grep with word boundary for C="+ grep("\\bC\\b", text));
    System.out.println("Should be blank: grep exactly for C="+ grep(beforeWord+"C"+afterWord, text));
    // Make sure the first and last cases work OK.

    text = "C is a language that should have been named differently.";
    System.out.println("text="+text);
    System.out.println("grep exactly for C="+ grep(beforeWord+"C"+afterWord, text));

    text = "One language that should have been named differently is C";
    System.out.println("text="+text);
    System.out.println("grep exactly for C="+ grep(beforeWord+"C"+afterWord, text));

    //Make sure we don't get false positives
    text = "The letter 'c' can be hard as in Cat, or soft as in Cindy. Computer languages should not require disambiguation (e.g. Ruby, Python vs. Fortran, Hadoop)";
    System.out.println("text="+text);
    System.out.println("Should be blank: grep exactly for C="+ grep(beforeWord+"C"+afterWord, text));

P.S. My thanks to http://regexpal.com/ without whom the regex world would be very miserable!

Receive result from DialogFragment

In my case I needed to pass arguments to a targetFragment. But I got exception "Fragment already active". So I declared an Interface in my DialogFragment which parentFragment implemented. When parentFragment started a DialogFragment , it set itself as TargetFragment. Then in DialogFragment I called

 ((Interface)getTargetFragment()).onSomething(selectedListPosition);

mysql delete under safe mode

Googling around, the popular answer seems to be "just turn off safe mode":

SET SQL_SAFE_UPDATES = 0;
DELETE FROM instructor WHERE salary BETWEEN 13000 AND 15000;
SET SQL_SAFE_UPDATES = 1;

If I'm honest, I can't say I've ever made a habit of running in safe mode. Still, I'm not entirely comfortable with this answer since it just assumes you should go change your database config every time you run into a problem.

So, your second query is closer to the mark, but hits another problem: MySQL applies a few restrictions to subqueries, and one of them is that you can't modify a table while selecting from it in a subquery.

Quoting from the MySQL manual, Restrictions on Subqueries:

In general, you cannot modify a table and select from the same table in a subquery. For example, this limitation applies to statements of the following forms:

DELETE FROM t WHERE ... (SELECT ... FROM t ...);
UPDATE t ... WHERE col = (SELECT ... FROM t ...);
{INSERT|REPLACE} INTO t (SELECT ... FROM t ...);

Exception: The preceding prohibition does not apply if you are using a subquery for the modified table in the FROM clause. Example:

UPDATE t ... WHERE col = (SELECT * FROM (SELECT ... FROM t...) AS _t ...);

Here the result from the subquery in the FROM clause is stored as a temporary table, so the relevant rows in t have already been selected by the time the update to t takes place.

That last bit is your answer. Select target IDs in a temporary table, then delete by referencing the IDs in that table:

DELETE FROM instructor WHERE id IN (
  SELECT temp.id FROM (
    SELECT id FROM instructor WHERE salary BETWEEN 13000 AND 15000
  ) AS temp
);

SQLFiddle demo.

adding line break

string[] abcd = obj.show(); 

Response.Write(string.join("</br>", abcd));

How to check if the docker engine and a docker container are running?

Run this command in the terminal:

docker ps

If docker is not running, you wil get this message:

Error response from daemon: dial unix docker.raw.sock: connect: connection refused

How to copy std::string into std::vector<char>?

std::vector has a constructor that takes two iterators. You can use that:

std::string str = "hello";
std::vector<char> data(str.begin(), str.end());

If you already have a vector and want to add the characters at the end, you need a back inserter:

std::string str = "hello";
std::vector<char> data = /* ... */;
std::copy(str.begin(), str.end(), std::back_inserter(data));

How do I convert from a string to an integer in Visual Basic?

Please try this, VB.NET 2010:

  1. Integer.TryParse(txtPrice.Text, decPrice)
  2. decPrice = Convert.ToInt32(txtPrice.Text)

From Mola Tshepo Kingsley (WWW.TUT.AC.ZA)

Android, Java: HTTP POST Request

I used the following code to send HTTP POST from my android client app to C# desktop app on my server:

// Create a new HttpClient and Post Header
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://www.yoursite.com/script.php");

try {
    // Add your data
    List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
    nameValuePairs.add(new BasicNameValuePair("id", "12345"));
    nameValuePairs.add(new BasicNameValuePair("stringdata", "AndDev is Cool!"));
    httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

    // Execute HTTP Post Request
    HttpResponse response = httpclient.execute(httppost);

} catch (ClientProtocolException e) {
    // TODO Auto-generated catch block
} catch (IOException e) {
    // TODO Auto-generated catch block
}

I worked on reading the request from a C# app on my server (something like a web server little application). I managed to read request posted data using the following code:

server = new HttpListener();
server.Prefixes.Add("http://*:50000/");
server.Start();

HttpListenerContext context = server.GetContext();
HttpListenerContext context = obj as HttpListenerContext;
HttpListenerRequest request = context.Request;

StreamReader sr = new StreamReader(request.InputStream);
string str = sr.ReadToEnd();

how to use JSON.stringify and json_decode() properly

When you use JSON stringify then use html_entity_decode first before json_decode.

$tempData = html_entity_decode($tempData);
$cleanData = json_decode($tempData);

Loading state button in Bootstrap 3

You need to detect the click from js side, your HTML remaining same. Note: this method is deprecated since v3.5.5 and removed in v4.

$("button").click(function() {
    var $btn = $(this);
    $btn.button('loading');
    // simulating a timeout
    setTimeout(function () {
        $btn.button('reset');
    }, 1000);
});

Also, don't forget to load jQuery and Bootstrap js (based on jQuery) file in your page.

JSFIDDLE

Official Documentation

Difference between no-cache and must-revalidate

Agreed with part of @Jeffrey Fox's answer:

max-age=0, must-revalidate and no-cache aren't exactly identical.

Not agreed with this part:

With no-cache, it would just show the cached content, which would be probably preferred by the user (better to have something stale than nothing at all).

What should implementations do when cache-control: no-cache revalidation failed is just not specified in the RFC document. It's all up to implementations. They may throw a 504 error like cache-control: must-revalidate or just serve a stale copy from cache.

How can I return two values from a function in Python?

And this is an alternative.If you are returning as list then it is simple to get the values.

def select_choice():
    ...
    return [i, card]

values = select_choice()

print values[0]
print values[1]

How do I modify a MySQL column to allow NULL?

Under some circumstances (if you get "ERROR 1064 (42000): You have an error in your SQL syntax;...") you need to do

ALTER TABLE mytable MODIFY mytable.mycolumn varchar(255);

Jackson - best way writes a java list to a json array

In objectMapper we have writeValueAsString() which accepts object as parameter. We can pass object list as parameter get the string back.

List<Apartment> aptList =  new ArrayList<Apartment>();
    Apartment aptmt = null;
    for(int i=0;i<5;i++){
         aptmt= new Apartment();
         aptmt.setAptName("Apartment Name : ArrowHead Ranch");
         aptmt.setAptNum("3153"+i);
         aptmt.setPhase((i+1));
         aptmt.setFloorLevel(i+2);
         aptList.add(aptmt);
    }
mapper.writeValueAsString(aptList)

"Cannot send session cache limiter - headers already sent"

"Headers already sent" means that your PHP script already sent the HTTP headers, and as such it can't make modifications to them now.

Check that you don't send ANY content before calling session_start. Better yet, just make session_start the first thing you do in your PHP file (so put it at the absolute beginning, before all HTML etc).

How to POST request using RestSharp

As of 2017 I post to a rest service and getting the results from it like that:

        var loginModel = new LoginModel();
        loginModel.DatabaseName = "TestDB";
        loginModel.UserGroupCode = "G1";
        loginModel.UserName = "test1";
        loginModel.Password = "123";

        var client = new RestClient(BaseUrl);

        var request = new RestRequest("/Connect?", Method.POST);
        request.RequestFormat = DataFormat.Json;
        request.AddBody(loginModel);

        var response = client.Execute(request);

        var obj = JObject.Parse(response.Content);

        LoginResult result = new LoginResult
        {
            Status = obj["Status"].ToString(),
            Authority = response.ResponseUri.Authority,
            SessionID = obj["SessionID"].ToString()
        };

MomentJS getting JavaScript Date in UTC

A timestamp is a point in time. Typically this can be represented by a number of milliseconds past an epoc (the Unix Epoc of Jan 1 1970 12AM UTC). The format of that point in time depends on the time zone. While it is the same point in time, the "hours value" is not the same among time zones and one must take into account the offset from the UTC.

Here's some code to illustrate. A point is time is captured in three different ways.

var moment = require( 'moment' );

var localDate = new Date();
var localMoment = moment();
var utcMoment = moment.utc();
var utcDate = new Date( utcMoment.format() );

//These are all the same
console.log( 'localData unix = ' + localDate.valueOf() );
console.log( 'localMoment unix = ' + localMoment.valueOf() );
console.log( 'utcMoment unix = ' + utcMoment.valueOf() );

//These formats are different
console.log( 'localDate = ' + localDate );
console.log( 'localMoment string = ' + localMoment.format() );
console.log( 'utcMoment string = ' + utcMoment.format() );
console.log( 'utcDate  = ' + utcDate );

//One to show conversion
console.log( 'localDate as UTC format = ' + moment.utc( localDate ).format() );
console.log( 'localDate as UTC unix = ' + moment.utc( localDate ).valueOf() );

Which outputs this:

localData unix = 1415806206570
localMoment unix = 1415806206570
utcMoment unix = 1415806206570
localDate = Wed Nov 12 2014 10:30:06 GMT-0500 (EST)
localMoment string = 2014-11-12T10:30:06-05:00
utcMoment string = 2014-11-12T15:30:06+00:00
utcDate  = Wed Nov 12 2014 10:30:06 GMT-0500 (EST)
localDate as UTC format = 2014-11-12T15:30:06+00:00
localDate as UTC unix = 1415806206570

In terms of milliseconds, each are the same. It is the exact same point in time (though in some runs, the later millisecond is one higher).

As far as format, each can be represented in a particular timezone. And the formatting of that timezone'd string looks different, for the exact same point in time!

Are you going to compare these time values? Just convert to milliseconds. One value of milliseconds is always less than, equal to or greater than another millisecond value.

Do you want to compare specific 'hour' or 'day' values and worried they "came from" different timezones? Convert to UTC first using moment.utc( existingDate ), and then do operations. Examples of those conversions, when coming out of the DB, are the last console.log calls in the example.

Android Studio Image Asset Launcher Icon Background Color

You have two ways:

1) In Background Layer > Scaling, reduce the Resize to 1

enter image description here

and then in Legacy > Legacy Icon set Shape as None

enter image description here


2) in Background Layer > Scaling > Source Asset, you can set an image as a 1x1 pixel (or any size) transparent.png image (you've already created).

enter image description here

and then in Legacy > Legacy Icon set Shape as None

enter image description here

The right way of setting <a href=""> when it's a local file

This can happen when you are running IIS and you run the html page through it, then the Local file system will not be accessible.

To make your link work locally the run the calling html page directly from file browser not visual studio F5 or IIS simply click it to open from the file system, and make sure you are using the link like this:

<a href="file:///F:/VS_2015_WorkSpace/Projects/xyz/Intro.html">Intro</a>

How can I get a specific number child using CSS?

For IE 7 & 8 (and other browsers without CSS3 support not including IE6) you can use the following to get the 2nd and 3rd children:

2nd Child:

td:first-child + td

3rd Child:

td:first-child + td + td

Then simply add another + td for each additional child you wish to select.

If you want to support IE6 that can be done too! You simply need to use a little javascript (jQuery in this example):

$(function() {
    $('td:first-child').addClass("firstChild");
    $(".table-class tr").each(function() {
        $(this).find('td:eq(1)').addClass("secondChild");
        $(this).find('td:eq(2)').addClass("thirdChild");
    });
});

Then in your css you simply use those class selectors to make whatever changes you like:

table td.firstChild { /*stuff here*/ }
table td.secondChild { /*stuff to apply to second td in each row*/ }

PIL image to array (numpy array to array) - Python

I think what you are looking for is:

list(im.getdata())

or, if the image is too big to load entirely into memory, so something like that:

for pixel in iter(im.getdata()):
    print pixel

from PIL documentation:

getdata

im.getdata() => sequence

Returns the contents of an image as a sequence object containing pixel values. The sequence object is flattened, so that values for line one follow directly after the values of line zero, and so on.

Note that the sequence object returned by this method is an internal PIL data type, which only supports certain sequence operations, including iteration and basic sequence access. To convert it to an ordinary sequence (e.g. for printing), use list(im.getdata()).

How to install a previous exact version of a NPM package?

In my opinion that is easiest and fastest way:

$ npm -v

4.2.0

$ npm install -g npm@latest-3

...

$ npm -v

3.10.10

Getting a random value from a JavaScript array

A generic way to get random element(s):

_x000D_
_x000D_
let some_array = ['Jan', 'Feb', 'Mar', 'Apr', 'May'];_x000D_
let months = random_elems(some_array, 3);_x000D_
_x000D_
console.log(months);_x000D_
_x000D_
function random_elems(arr, count) {_x000D_
  let len = arr.length;_x000D_
  let lookup = {};_x000D_
  let tmp = [];_x000D_
_x000D_
  if (count > len)_x000D_
    count = len;_x000D_
_x000D_
  for (let i = 0; i < count; i++) {_x000D_
    let index;_x000D_
    do {_x000D_
      index = ~~(Math.random() * len);_x000D_
    } while (index in lookup);_x000D_
    lookup[index] = null;_x000D_
    tmp.push(arr[index]);_x000D_
  }_x000D_
_x000D_
  return tmp;_x000D_
}
_x000D_
_x000D_
_x000D_

why numpy.ndarray is object is not callable in my simple for python loop

The error TypeError: 'numpy.ndarray' object is not callable means that you tried to call a numpy array as a function.

Use

Z=XY[0]+XY[1]

Instead of

Z=XY(i,0)+XY(i,1)

How to add anything in <head> through jquery/javascript?

JavaScript:

document.getElementsByTagName('head')[0].appendChild( ... );

Make DOM element like so:

link=document.createElement('link');
link.href='href';
link.rel='rel';

document.getElementsByTagName('head')[0].appendChild(link);

How to set commands output as a variable in a batch file

If you don't want to output to a temp file and then read into a variable, this code stores result of command direct into a variable:

FOR /F %i IN ('findstr testing') DO set VARIABLE=%i
echo %VARIABLE%

If you want to enclose search string in double quotes:

FOR /F %i IN ('findstr "testing"') DO set VARIABLE=%i

If you want to store this code in a batch file, add an extra % symbol:

FOR /F %%i IN ('findstr "testing"') DO set VARIABLE=%%i

A useful example to count the number of files in a directory & store in a variable: (illustrates piping)

FOR /F %i IN ('dir /b /a-d "%cd%" ^| find /v /c "?"') DO set /a count=%i

Note the use of single quotes instead of double quotes " or grave accent ` in the command brackets. This is cleaner alternative to delims, tokens or usebackq in for loop.

Tested on Win 10 CMD.

Where can I find MySQL logs in phpMyAdmin?

In phpMyAdmin 4.0, you go to Status > Monitor. In there you can enable the slow query log and general log, see a live monitor, select a portion of the graph, see the related queries and analyse them.

Can you delete multiple branches in one command with Git?

Well, in the worst case, you could use:

git branch | grep '3\.2' | xargs git branch -D

Cannot open include file: 'unistd.h': No such file or directory

The "uni" in unistd stands for "UNIX" - you won't find it on a Windows system.

Most widely used, portable libraries should offer alternative builds or detect the platform and only try to use headers/functions that will be provided, so it's worth checking documentation to see if you've missed some build step - e.g. perhaps running "make" instead of loading a ".sln" Visual C++ solution file.

If you need to fix it yourself, remove the include and see which functions are actually needed, then try to find a Windows equivalent.

Using grep to search for hex strings in a file

grep has a -P switch allowing to use perl regexp syntax the perl regex allows to look at bytes, using \x.. syntax.

so you can look for a given hex string in a file with: grep -aP "\xdf"

but the outpt won't be very useful; indeed better do a regexp on the hexdump output;

The grep -P can be useful however to just find files matrching a given binary pattern. Or to do a binary query of a pattern that actually happens in text (see for example How to regexp CJK ideographs (in utf-8) )

How can I get the URL of the current tab from a Google Chrome extension?

You have to check on this.

HTML

<button id="saveActionId"> Save </button>

manifest.json

  "permissions": [
    "activeTab",
    "tabs"
   ]

JavaScript
The below code will save all the urls of active window into JSON object as part of button click.

var saveActionButton = document.getElementById('saveActionId');
saveActionButton.addEventListener('click', function() {
    myArray = [];
    chrome.tabs.query({"currentWindow": true},  //{"windowId": targetWindow.id, "index": tabPosition});
    function (array_of_Tabs) {  //Tab tab
        arrayLength = array_of_Tabs.length;
        //alert(arrayLength);
        for (var i = 0; i < arrayLength; i++) {
            myArray.push(array_of_Tabs[i].url);
        }
        obj = JSON.parse(JSON.stringify(myArray));
    });
}, false);

What does "hashable" mean in Python?

For creating a hashing table from scratch, all the values has to set to "None" and modified once a requirement arises. Hashable objects refers to the modifiable datatypes(Dictionary,lists etc). Sets on the other hand cannot be reinitialized once assigned, so sets are non hashable. Whereas, The variant of set() -- frozenset() -- is hashable.

Returning a boolean value in a JavaScript function

Don't forget to use var/let while declaring any variable.See below examples for JS compiler behaviour.

function  func(){
return true;
}

isBool = func();
console.log(typeof (isBool));   // output - string


let isBool = func();
console.log(typeof (isBool));   // output - boolean

How to handle notification when app in background in Firebase

1. Why is this happening?

There are two types of messages in FCM (Firebase Cloud Messaging):

  1. Display Messages: These messages trigger the onMessageReceived() callback only when your app is in foreground
  2. Data Messages: Theses messages trigger the onMessageReceived() callback even if your app is in foreground/background/killed

NOTE: Firebase team have not developed a UI to send data-messages to your devices, yet. You should use your server for sending this type!



2. How to?

To achieve this, you have to perform a POST request to the following URL:

POST https://fcm.googleapis.com/fcm/send

Headers

  • Key: Content-Type, Value: application/json
  • Key: Authorization, Value: key=<your-server-key>

Body using topics

{
    "to": "/topics/my_topic",
    "data": {
        "my_custom_key": "my_custom_value",
        "my_custom_key2": true
     }
}

Or if you want to send it to specific devices

{
    "data": {
        "my_custom_key": "my_custom_value",
        "my_custom_key2": true
     },
    "registration_ids": ["{device-token}","{device2-token}","{device3-token}"]
}


NOTE: Be sure you're not adding JSON key notification
NOTE: To get your server key, you can find it in the firebase console: Your project -> settings -> Project settings -> Cloud messaging -> Server Key

3. How to handle the push notification message?

This is how you handle the received message:

@Override
public void onMessageReceived(RemoteMessage remoteMessage) { 
     Map<String, String> data = remoteMessage.getData();
     String myCustomKey = data.get("my_custom_key");

     // Manage data
}

Python calling method in class

The first argument of all methods is usually called self. It refers to the instance for which the method is being called.

Let's say you have:

class A(object):
    def foo(self):
        print 'Foo'

    def bar(self, an_argument):
        print 'Bar', an_argument

Then, doing:

a = A()
a.foo() #prints 'Foo'
a.bar('Arg!') #prints 'Bar Arg!'

There's nothing special about this being called self, you could do the following:

class B(object):
    def foo(self):
        print 'Foo'

    def bar(this_object):
        this_object.foo()

Then, doing:

b = B()
b.bar() # prints 'Foo'

In your specific case:

dangerous_device = MissileDevice(some_battery)
dangerous_device.move(dangerous_device.RIGHT) 

(As suggested in comments MissileDevice.RIGHT could be more appropriate here!)

You could declare all your constants at module level though, so you could do:

dangerous_device.move(RIGHT)

This, however, is going to depend on how you want your code to be organized!

Sort a single String in Java

No there is no built-in String method. You can convert it to a char array, sort it using Arrays.sort and convert that back into a String.

String test= "edcba";
char[] ar = test.toCharArray();
Arrays.sort(ar);
String sorted = String.valueOf(ar);

Or, when you want to deal correctly with locale-specific stuff like uppercase and accented characters:

import java.text.Collator;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Locale;

public class Test
{
  public static void main(String[] args)
  {
    Collator collator = Collator.getInstance(new Locale("fr", "FR"));
    String original = "éDedCBcbAàa";
    String[] split = original.split("");
    Arrays.sort(split, collator);
    String sorted = "";
    for (int i = 0; i < split.length; i++)
    {
      sorted += split[i];
    }
    System.out.println(sorted); // "aAàbBcCdDeé"
  }
}

Most efficient way to find smallest of 3 numbers Java?

Simply use this math function

System.out.println(Math.min(a,b,c));

You will get the answer in single line.

What is the difference between C++ and Visual C++?

C++ is a general-purpose programming language. It is regarded as a middle-level language, as it comprises a combination of both high-level and low-level language features. It was developed by Bjarne Stroustrup starting in 1979 at Bell Labs as an enhancement to the C programming language and originally named "C with Classes". It was renamed to C++ in 1983.

C++ is widely used in the software industry. Some of its application domains include systems software, application software, device drivers, embedded software, high-performance server and client applications, and entertainment software such as video games. Several groups provide both free and proprietary C++ compiler software, including the GNU Project, Microsoft, Intel, Borland and others.


Microsoft Visual C++ (often abbreviated as MSVC or VC++) is an integrated development environment (IDE) product from Microsoft for the C, C++, and C++/CLI programming languages. MSVC is proprietary software; it was originally a standalone product but later became a part of Visual Studio and made available in both trialware and freeware forms. It features tools for developing and debugging C++ code, especially code written for Windows API, DirectX and .NET Framework.


So the main difference between them is that they are different things. The former is a programming language, while the latter is a commercial integrated development environment (IDE).

pandas groupby sort descending order

You can do a sort_values() on the dataframe before you do the groupby. Pandas preserves the ordering in the groupby.

In [44]: d.head(10)
Out[44]:
              name transcript  exon
0  ENST00000456328          2     1
1  ENST00000450305          2     1
2  ENST00000450305          2     2
3  ENST00000450305          2     3
4  ENST00000456328          2     2
5  ENST00000450305          2     4
6  ENST00000450305          2     5
7  ENST00000456328          2     3
8  ENST00000450305          2     6
9  ENST00000488147          1    11

for _, a in d.head(10).sort_values(["transcript", "exon"]).groupby(["name", "transcript"]): print(a)
              name transcript  exon
1  ENST00000450305          2     1
2  ENST00000450305          2     2
3  ENST00000450305          2     3
5  ENST00000450305          2     4
6  ENST00000450305          2     5
8  ENST00000450305          2     6
              name transcript  exon
0  ENST00000456328          2     1
4  ENST00000456328          2     2
7  ENST00000456328          2     3
              name transcript  exon
9  ENST00000488147          1    11

Disable double-tap "zoom" option in browser on touch devices

Note (as of 2020-08-04): this solution does not appear to work in iOS Safari v12+. I will update this answer and delete this note once I find a clear solution that covers iOS Safari.

CSS-only solution

Add touch-action: manipulation to any element on which you want to disable double tap zoom, like with the following disable-dbl-tap-zoom class:

.disable-dbl-tap-zoom {
  touch-action: manipulation;
}

From the touch-action docs (emphasis mine):

manipulation

Enable panning and pinch zoom gestures, but disable additional non-standard gestures such as double-tap to zoom.

This value works on Android and on iOS.

React - clearing an input value after form submit

This is the value that i want to clear and create it in state 1st STEP

state={
TemplateCode:"",
}

craete submitHandler function for Button or what you want 3rd STEP

submitHandler=()=>{
this.clear();//this is function i made
}

This is clear function Final STEP

clear = () =>{
  this.setState({
    TemplateCode: ""//simply you can clear Templatecode
  });
}

when click button Templatecode is clear 2nd STEP

<div class="col-md-12" align="right">
  <button id="" type="submit" class="btn btnprimary" onClick{this.submitHandler}> Save 
  </button>
</div>

How can I insert data into Database Laravel?

First method you can try this

$department->department_name = $request->department_name;
$department->status = $request->status;
$department->save();

Another way to insert records into the database with create function

$department = new Department;           
// Another Way to insert records
$department->create($request->all());

return redirect('admin/departments');

You need to set the filledby in Department model

namespace App;

use Illuminate\Database\Eloquent\Model;

class Department extends Model
{
    protected $fillable = ['department_name','status'];
} 

How to read a text file into a string variable and strip newlines?

file = open("myfile.txt", "r")
lines = file.readlines()
str = ''                                     #string declaration

for i in range(len(lines)):
    str += lines[i].rstrip('\n') + ' '

print str

Undefined reference to pow( ) in C, despite including math.h

You need to link with the math library:

gcc -o sphere sphere.c -lm

The error you are seeing: error: ld returned 1 exit status is from the linker ld (part of gcc that combines the object files) because it is unable to find where the function pow is defined.

Including math.h brings in the declaration of the various functions and not their definition. The def is present in the math library libm.a. You need to link your program with this library so that the calls to functions like pow() are resolved.

Rails: Get Client IP address

For anyone interested and using a newer rails and the Devise gem: Devise's "trackable" option includes a column for current/last_sign_in_ip in the users table.

Google Play on Android 4.0 emulator

For future visitors.

As of now Android 4.2.2 platform includes Google Play services. Just use an emulator running Jelly Bean. Details can be found here:

Setup Google Play Services SDK

EDIT:

Another option is to use Genymotion (runs way faster)

EDIT 2:

As @gdw2 commented: "setting up the Google Play Services SDK does not install a working Google Play app -- it just enables certain services provided by the SDK"

After version 2.0 Genymotion does not come with Play Services by default, but it can be easily installed manually. Just download the right version from here and drag and drop into the virtual device (emulador).

Unable to open debugger port in IntelliJ IDEA

My assumption that this exception usually occurs when Tomcat is improperly closed and still holding the ports. Usually it is enough to kill any process listening to 1099 port. For Window 10:

netstat -aon | find "1099"


taskkill /F /PID $processId

Remove legend ggplot 2.2

There might be another solution to this:
Your code was:

geom_point(aes(..., show.legend = FALSE))

You can specify the show.legend parameter after the aes call:

geom_point(aes(...), show.legend = FALSE)

then the corresponding legend should disappear

How should I escape commas and speech marks in CSV files so they work in Excel?

According to Yashu's instructions, I wrote the following function (it's PL/SQL code, but it should be easily adaptable to any other language).

FUNCTION field(str IN VARCHAR2) RETURN VARCHAR2 IS
    C_NEWLINE CONSTANT CHAR(1) := '
'; -- newline is intentional

    v_aux VARCHAR2(32000);
    v_has_double_quotes BOOLEAN;
    v_has_comma BOOLEAN;
    v_has_newline BOOLEAN;
BEGIN
    v_has_double_quotes := instr(str, '"') > 0;
    v_has_comma := instr(str,',') > 0;
    v_has_newline := instr(str, C_NEWLINE) > 0;

    IF v_has_double_quotes OR v_has_comma OR v_has_newline THEN
        IF v_has_double_quotes THEN
            v_aux := replace(str,'"','""');
        ELSE
            v_aux := str;
        END IF;
        return '"'||v_aux||'"';
    ELSE
        return str;
    END IF;
END;

Adb Devices can't find my phone

I have a ZTE Crescent phone (Orange San Francisco II).

When I connect the phone to the USB a disk shows up in OS X named 'ZTE_USB_Driver'.

Running adb devices displays no connected devices. But after I eject the 'ZTE_USB_Driver' disk from OS X, and run adb devices again the phone shows up as connected.

How can I make a UITextField move up when the keyboard is present - on starting to edit?

Swift 4 .

You Can Easily Move Up And Down UITextField Or UIView With UIKeyBoard With Animation enter image description here

import UIKit

class ViewController: UIViewController, UITextFieldDelegate {

    @IBOutlet var textField: UITextField!
    @IBOutlet var chatView: UIView!

    override func viewDidLoad() {
        super.viewDidLoad()
        NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange), name: .UIKeyboardWillChangeFrame, object: nil)
    }

    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        textField.resignFirstResponder()
    }

    @objc func keyboardWillChange(notification: NSNotification) {

        let duration = notification.userInfo![UIKeyboardAnimationDurationUserInfoKey] as! Double
        let curve = notification.userInfo![UIKeyboardAnimationCurveUserInfoKey] as! UInt
        let curFrame = (notification.userInfo![UIKeyboardFrameBeginUserInfoKey] as! NSValue).cgRectValue
        let targetFrame = (notification.userInfo![UIKeyboardFrameEndUserInfoKey] as! NSValue).cgRectValue
        let deltaY = targetFrame.origin.y - curFrame.origin.y
        print("deltaY",deltaY)

        UIView.animateKeyframes(withDuration: duration, delay: 0.0, options: UIViewKeyframeAnimationOptions(rawValue: curve), animations: {
            self.chatView.frame.origin.y+=deltaY // Here You Can Change UIView To UITextField
        },completion: nil)
    }

    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        textField.resignFirstResponder()
        return true
    }

}

How to check the maximum number of allowed connections to an Oracle database?

Use gv$session for RAC, if you want get the total number of session across the cluster.

How to delete directory content in Java?

Use FileUtils with FileUtils.deleteDirectory();

How to do a GitHub pull request

For those of us who have a github.com account, but only get a nasty error message when we type "git" into the command-line, here's how to do it all in your browser :)

  1. Same as Tim and Farhan wrote: Fork your own copy of the project: Step 1: Fork
  2. After a few seconds, you'll be redirected to your own forked copy of the project: Step 2
  3. Navigate to the file(s) you need to change and click "Edit this file" in the toolbar: Step 3: Edit a file
  4. After editing, write a few words describing the changes and then "Commit changes", just as well to the master branch (since this is only your own copy and not the "main" project). Step 4: Commit changes
  5. Repeat steps 3 and 4 for all files you need to edit, and then go back to the root of your copy of the project. There, click the green "Compare, review..." button: Step 5: Start submit
  6. Finally, click "Create pull request" ..and then "Create pull request" again after you've double-checked your request's heading and description: enter image description here

How do I consume the JSON POST data in an Express application

For Express v4+

install body-parser from the npm.

$ npm install body-parser

https://www.npmjs.org/package/body-parser#installation

var express    = require('express')
var bodyParser = require('body-parser')

var app = express()

// parse application/json
app.use(bodyParser.json())

app.use(function (req, res, next) {
  console.log(req.body) // populated!
  next()
})

What's the difference between an argument and a parameter?

Oracle's Java tutorials define this distinction thusly: "Parameters refers to the list of variables in a method declaration. Arguments are the actual values that are passed in when the method is invoked. When you invoke a method, the arguments used must match the declaration's parameters in type and order."

A more detailed discussion of parameters and arguments: https://docs.oracle.com/javase/tutorial/java/javaOO/arguments.html

How does strtok() split the string into tokens in C?

Here is my implementation which uses hash table for the delimiter, which means it O(n) instead of O(n^2) (here is a link to the code):

#include<stdio.h>
#include<stdlib.h>
#include<string.h>

#define DICT_LEN 256

int *create_delim_dict(char *delim)
{
    int *d = (int*)malloc(sizeof(int)*DICT_LEN);
    memset((void*)d, 0, sizeof(int)*DICT_LEN);

    int i;
    for(i=0; i< strlen(delim); i++) {
        d[delim[i]] = 1;
    }
    return d;
}



char *my_strtok(char *str, char *delim)
{

    static char *last, *to_free;
    int *deli_dict = create_delim_dict(delim);

    if(!deli_dict) {
        /*this check if we allocate and fail the second time with entering this function */
        if(to_free) {
            free(to_free);
        }
        return NULL;
    }

    if(str) {
        last = (char*)malloc(strlen(str)+1);
        if(!last) {
            free(deli_dict);
            return NULL;
        }
        to_free = last;
        strcpy(last, str);
    }

    while(deli_dict[*last] && *last != '\0') {
        last++;
    }
    str = last;
    if(*last == '\0') {
        free(deli_dict);
        free(to_free);
        deli_dict = NULL;
        to_free = NULL;
        return NULL;
    }
    while (*last != '\0' && !deli_dict[*last]) {
        last++;
    }

    *last = '\0';
    last++;

    free(deli_dict);
    return str;
}

int main()
{
    char * str = "- This, a sample string.";
    char *del = " ,.-";
    char *s = my_strtok(str, del);
    while(s) {
        printf("%s\n", s);
        s = my_strtok(NULL, del);
    }
    return 0;
}

jQuery checkbox onChange

$('input[type=checkbox]').change(function () {
    alert('changed');
});

Warnings Your Apk Is Using Permissions That Require A Privacy Policy: (android.permission.READ_PHONE_STATE)

you need to specify the min and target sdk version in the manifest file.
If not the android.permission.READ_PHONE_STATE will be added automaticly while exporting your apk file.

<uses-sdk
        android:minSdkVersion="9"
        android:targetSdkVersion="19" />

How to send only one UDP packet with netcat?

If you are using bash, you might as well write

echo -n "hello" >/dev/udp/localhost/8000

and avoid all the idiosyncrasies and incompatibilities of netcat.

This also works sending to other hosts, ex:

echo -n "hello" >/dev/udp/remotehost/8000

These are not "real" devices on the file system, but bash "special" aliases. There is additional information in the Bash Manual.

'node' is not recognized as an internal or an external command, operable program or batch file while using phonegap/cordova

If you install Node using the windows installer, there is nothing you have to do. It adds path to node and npm.

You can also use Windows setx command for changing system environment variables. No reboot is required. Just logout/login. Or just open a new cmd window, if you want to see the changing there.

setx PATH "%PATH%;C:\Program Files\nodejs"

React Native fetch() Network Request Failed

in my case i have https url but fetch return Network Request Failed error so i just stringify the body and it s working fun

_x000D_
_x000D_
fetch('https://mywebsite.com/endpoint/', {
  method: 'POST',
  headers: {
    Accept: 'application/json',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    firstParam: 'yourValue',
    secondParam: 'yourOtherValue'
  })
});
_x000D_
_x000D_
_x000D_

Installing jdk8 on ubuntu- "unable to locate package" update doesn't fix

Ubuntu defaults to the OpenJDK packages. If you want to install Oracle's JDK, then you need to visit their download page, and grab the package from there.

Once you've installed the Oracle JDK, you also need to update the following (system defaults will point to OpenJDK):

export JAVA_HOME=/my/path/to/oracle/jdk
export PATH=$JAVA_HOME/bin:$PATH

If you want the Oracle JDK to be the default for your system, you will need to remove the OpenJDK packages, and update your profile environment variables.