Programs & Examples On #Mappers

Hibernate Error executing DDL via JDBC Statement

Dialects are removed in recent SQL so use

  <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL57Dialect"/>

Container is running beyond memory limits

Running yarn on Windows Linux subsystem with Ubunto OS, error "running beyond virtual memory limits, Killing container" I resolved it by disabling virtual memory check in the file yarn-site.xml

<property> <name>yarn.nodemanager.vmem-check-enabled</name> <value>false</value> </property> 

Non-numeric Argument to Binary Operator Error in R

Because your question is phrased regarding your error message and not whatever your function is trying to accomplish, I will address the error.

- is the 'binary operator' your error is referencing, and either CurrentDay or MA (or both) are non-numeric.

A binary operation is a calculation that takes two values (operands) and produces another value (see wikipedia for more). + is one such operator: "1 + 1" takes two operands (1 and 1) and produces another value (2). Note that the produced value isn't necessarily different from the operands (e.g., 1 + 0 = 1).

R only knows how to apply + (and other binary operators, such as -) to numeric arguments:

> 1 + 1
[1] 2
> 1 + 'one'
Error in 1 + "one" : non-numeric argument to binary operator

When you see that error message, it means that you are (or the function you're calling is) trying to perform a binary operation with something that isn't a number.

EDIT:

Your error lies in the use of [ instead of [[. Because Day is a list, subsetting with [ will return a list, not a numeric vector. [[, however, returns an object of the class of the item contained in the list:

> Day <- Transaction(1, 2)["b"]
> class(Day)
[1] "list"
> Day + 1
Error in Day + 1 : non-numeric argument to binary operator

> Day2 <- Transaction(1, 2)[["b"]]
> class(Day2)
[1] "numeric"
> Day2 + 1
[1] 3

Transaction, as you've defined it, returns a list of two vectors. Above, Day is a list contain one vector. Day2, however, is simply a vector.

Installation error: INSTALL_FAILED_OLDER_SDK

Mate, my advice is to change virtual device. Download "Genimotion" application, its easy to use and there are a lot of any devices you need

Centering the pagination in bootstrap

solution for Bootstrap 4

You can use it Alignment use this class justify-content-center

Change the alignment of pagination components with flexbox utilities.

and learn more about it pagination

_x000D_
_x000D_
<link href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" rel="stylesheet"/>_x000D_
_x000D_
_x000D_
_x000D_
<nav aria-label="Page navigation example">_x000D_
  <ul class="pagination justify-content-center">_x000D_
    <li class="page-item disabled">_x000D_
      <a class="page-link" href="#" tabindex="-1">Previous</a>_x000D_
    </li>_x000D_
    <li class="page-item"><a class="page-link" href="#">1</a></li>_x000D_
    <li class="page-item"><a class="page-link" href="#">2</a></li>_x000D_
    <li class="page-item"><a class="page-link" href="#">3</a></li>_x000D_
    <li class="page-item">_x000D_
      <a class="page-link" href="#">Next</a>_x000D_
    </li>_x000D_
  </ul>_x000D_
</nav>
_x000D_
_x000D_
_x000D_

How to display a Yes/No dialog box on Android?

Show dialog anonymously as chain of commands & without defining another object:

 new AlertDialog.Builder(this).setTitle("Confirm Delete?")
                        .setMessage("Are you sure?")
                        .setPositiveButton("YES",
                                new DialogInterface.OnClickListener() {
                                    public void onClick(DialogInterface dialog, int which) {

                                       // Perform Action & Dismiss dialog                                 
                                        dialog.dismiss();
                                    }
                                })
                        .setNegativeButton("NO", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                // Do nothing
                                dialog.dismiss();
                            }
                        })
                        .create()
                        .show();

Create PostgreSQL ROLE (user) if it doesn't exist

The same solution as for Simulate CREATE DATABASE IF NOT EXISTS for PostgreSQL? should work - send a CREATE USER … to \gexec.

Workaround from within psql

SELECT 'CREATE USER my_user'
WHERE NOT EXISTS (SELECT FROM pg_catalog.pg_roles WHERE rolname = 'my_user')\gexec

Workaround from the shell

echo "SELECT 'CREATE USER my_user' WHERE NOT EXISTS (SELECT FROM pg_catalog.pg_roles WHERE rolname = 'my_user')\gexec" | psql

See accepted answer there for more details.

How can I reference a commit in an issue comment on GitHub?

To reference a commit, simply write its SHA-hash, and it'll automatically get turned into a link.

See also:

"unrecognized selector sent to instance" error in Objective-C

On my case I solved the problem after 2 hours :

The sender (a tabBar item) wasn't having any Referencing Outlet. So it was pointing nowhere.

Juste create a referencing outlet corresponding to your function.

Hope this could help you guys.

TypeError: worker() takes 0 positional arguments but 1 was given

When doing Flask Basic auth I got this error and then I realized I had wrapped_view(**kwargs) and it worked after changing it to wrapped_view(*args, **kwargs).

Get content of a cell given the row and column numbers

Try =index(ARRAY, ROW, COLUMN)

where: Array: select the whole sheet Row, Column: Your row and column references

That should be easier to understand to those looking at the formula.

SQL Server Escape an Underscore

I had a similar issue using like pattern '%_%' did not work - as the question indicates :-)

Using '%\_%' did not work either as this first \ is interpreted "before the like".

Using '%\\_%' works. The \\ (double backslash) is first converted to single \ (backslash) and then used in the like pattern.

SQL Insert Query Using C#

I assume you have a connection to your database and you can not do the insert parameters using c #.

You are not adding the parameters in your query. It should look like:

String query = "INSERT INTO dbo.SMS_PW (id,username,password,email) VALUES (@id,@username,@password, @email)";

SqlCommand command = new SqlCommand(query, db.Connection);
command.Parameters.Add("@id","abc");
command.Parameters.Add("@username","abc");
command.Parameters.Add("@password","abc");
command.Parameters.Add("@email","abc");

command.ExecuteNonQuery();

Updated:

using(SqlConnection connection = new SqlConnection(_connectionString))
{
    String query = "INSERT INTO dbo.SMS_PW (id,username,password,email) VALUES (@id,@username,@password, @email)";

    using(SqlCommand command = new SqlCommand(query, connection))
    {
        command.Parameters.AddWithValue("@id", "abc");
        command.Parameters.AddWithValue("@username", "abc");
        command.Parameters.AddWithValue("@password", "abc");
        command.Parameters.AddWithValue("@email", "abc");

        connection.Open();
        int result = command.ExecuteNonQuery();

        // Check Error
        if(result < 0)
            Console.WriteLine("Error inserting data into Database!");
    }
}

Best way to style a TextBox in CSS

You Also wanna put some text (placeholder) in the empty input box for the

_x000D_
_x000D_
.myClass {_x000D_
   ::-webkit-input-placeholder {_x000D_
    color: #f00;_x000D_
  }_x000D_
   ::-moz-placeholder {_x000D_
    color: #f00;_x000D_
  }_x000D_
  /* firefox 19+ */_x000D_
   :-ms-input-placeholder {_x000D_
    color: #f00;_x000D_
  }_x000D_
  /* ie */_x000D_
  input:-moz-placeholder {_x000D_
    color: #f00;_x000D_
  }_x000D_
}
_x000D_
<input type="text" class="myClass" id="fname" placeholder="Enter First Name Here!">
_x000D_
_x000D_
_x000D_

user to understand what to type.

Convert hex string (char []) to int?

i have done a similar thing, think it might help u its actually working for me

int main(){ int co[8],i;char ch[8];printf("please enter the string:");scanf("%s",ch);for(i=0;i<=7;i++){if((ch[i]>='A')&&(ch[i]<='F')){co[i]=(unsigned int)ch[i]-'A'+10;}else if((ch[i]>='0')&&(ch[i]<='9')){co[i]=(unsigned int)ch[i]-'0'+0;}}

here i have only taken a string of 8 characters. if u want u can add similar logic for 'a' to 'f' to give their equivalent hex values,i haven't done that cause i didn't needed it.

Matrix Multiplication in pure Python?

All the below answers would return you the list.Your need to convert it to matrix

def MATMUL(X, Y):
    rows_A = len(X)
    cols_A = len(X[0])
    rows_B = len(Y)
    cols_B = len(Y[0])

    if cols_A != rows_B:
        print "Matrices are not compatible to Multiply. Check condition C1==R2"
        return

    # Create the result matrix
    # Dimensions would be rows_A x cols_B
    C = [[0 for row in range(cols_B)] for col in range(rows_A)]
    print C

    for i in range(rows_A):
        for j in range(cols_B):
            for k in range(cols_A):
                C[i][j] += A[i][k] * B[k][j]

    C = numpy.matrix(C).reshape(len(A),len(B[0]))

    return C

Output PowerShell variables to a text file

I was lead here in my Google searching. In a show of good faith I have included what I pieced together from parts of this code and other code I've gathered along the way.

_x000D_
_x000D_
# This script is useful if you have attributes or properties that span across several commandlets_x000D_
# and you wish to export a certain data set but all of the properties you wish to export are not_x000D_
# included in only one commandlet so you must use more than one to export the data set you want_x000D_
#_x000D_
# Created: Joshua Biddle 08/24/2017_x000D_
# Edited: Joshua Biddle 08/24/2017_x000D_
#_x000D_
_x000D_
$A = Get-ADGroupMember "YourGroupName"_x000D_
_x000D_
# Construct an out-array to use for data export_x000D_
$Results = @()_x000D_
_x000D_
foreach ($B in $A)_x000D_
    {_x000D_
  # Construct an object_x000D_
        $myobj = Get-ADuser $B.samAccountName -Properties ScriptPath,Office_x000D_
  _x000D_
  # Fill the object_x000D_
  $Properties = @{_x000D_
  samAccountName = $myobj.samAccountName_x000D_
  Name = $myobj.Name _x000D_
  Office = $myobj.Office _x000D_
  ScriptPath = $myobj.ScriptPath_x000D_
  }_x000D_
_x000D_
        # Add the object to the out-array_x000D_
        $Results += New-Object psobject -Property $Properties_x000D_
        _x000D_
  # Wipe the object just to be sure_x000D_
        $myobj = $null_x000D_
    }_x000D_
_x000D_
# After the loop, export the array to CSV_x000D_
$Results | Select "samAccountName", "Name", "Office", "ScriptPath" | Export-CSV "C:\Temp\YourData.csv"
_x000D_
_x000D_
_x000D_

Cheers

disabling spring security in spring boot app

For me only excluding the following classes worked:

import org.springframework.boot.actuate.autoconfigure.security.servlet.ManagementWebSecurityAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.security.servlet.SecurityAutoConfiguration;

@SpringBootApplication(exclude = {SecurityAutoConfiguration.class, ManagementWebSecurityAutoConfiguration.class}) {
  // ... 
}

How to compare two vectors for equality element by element in C++?

Your code (vector1 == vector2) is correct C++ syntax. There is an == operator for vectors.

If you want to compare short vector with a portion of a longer vector, you can use theequal() operator for vectors. (documentation here)

Here's an example:

using namespace std;

if( equal(vector1.begin(), vector1.end(), vector2.begin()) )
    DoSomething();

PUT and POST getting 405 Method Not Allowed Error for Restful Web Services

I'm not sure if I am correct, but from the request header that you post:

Request headers

Accept: Application/json

Origin: chrome-extension://hgmloofddffdnphfgcellkdfbfbjeloo

User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.76 Safari/537.36

Content-Type: application/x-www-form-urlencoded

Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8

it seems like you didn't config your request body to JSON type.

Why does C++ compilation take so long?

A compiled language is always going to require a bigger initial overhead than an interpreted language. In addition, perhaps you didn't structure your C++ code very well. For example:

#include "BigClass.h"

class SmallClass
{
   BigClass m_bigClass;
}

Compiles a lot slower than:

class BigClass;

class SmallClass
{
   BigClass* m_bigClass;
}

Create a sample login page using servlet and JSP?

As I can see, you are comparing the message with the empty string using ==.

Its very hard to write the full code, but I can tell the flow of code - first, create db class & method inide that which will return the connection. second, create a servelet(ex-login.java) & import that db class onto that servlet. third, create instance of imported db class with the help of new operator & call the connection method of that db class. fourth, creaet prepared statement & execute statement & put this code in try catch block for exception handling.Use if-else condition in the try block to navigate your login page based on success or failure.

I hope, it will help you. If any problem, then please revert.

Nikhil Pahariya

Android Animation Alpha

Setting alpha to 1 before starting the animation worked for me:

AlphaAnimation animation1 = new AlphaAnimation(0.2f, 1.0f);
animation1.setDuration(500);
iv.setAlpha(1f);
iv.startAnimation(animation1);

At least on my tests, there's no flickering because of setting alpha before starting the animation. It just works fine.

PHP filesize MB/KB conversion

A complete example.

<?php
    $units = explode(' ','B KB MB GB TB PB');
    echo("<html><body>");
    echo('file size: ' . format_size(filesize("example.txt")));
    echo("</body></html>");


    function format_size($size) {

        $mod = 1024;

        for ($i = 0; $size > $mod; $i++) {
            $size /= $mod;
        }

        $endIndex = strpos($size, ".")+3;

        return substr( $size, 0, $endIndex).' '.$units[$i];
    }
?>

Adding header for HttpURLConnection

If you are using Java 8, use the code below.

URLConnection connection = url.openConnection();
HttpURLConnection httpConn = (HttpURLConnection) connection;

String basicAuth = Base64.getEncoder().encodeToString((username+":"+password).getBytes(StandardCharsets.UTF_8));
httpConn.setRequestProperty ("Authorization", "Basic "+basicAuth);

How to allow only integers in a textbox?

step by step

given you have a textbox as following,

<asp:TextBox ID="TextBox13" runat="server" 
  onkeypress="return functionx(event)" >
</asp:TextBox>

you create a JavaScript function like this:

     <script type = "text/javascript">
         function functionx(evt) 
         {
            if (evt.charCode > 31 && (evt.charCode < 48 || evt.charCode > 57))
                  {
                    alert("Allow Only Numbers");
                    return false;
                  }
          }
     </script>

the first part of the if-statement excludes the ASCII control chars, the or statements exclued anything, that is not a number

SQLSTATE[HY093]: Invalid parameter number: parameter was not defined

This error you are receiving :

SQLSTATE[HY093]: Invalid parameter number: parameter was not defined

is because the number of elements in $values & $matches is not the same or $matches contains more than 1 element.

If $matches contains more than 1 element, than the insert will fail, because there is only 1 column name referenced in the query(hash)

If $values & $matches do not contain the same number of elements then the insert will also fail, due to the query expecting x params but it is receiving y data $matches.

I believe you will also need to ensure the column hash has a unique index on it as well.

Try the code here:

<?php

/*** mysql hostname ***/
$hostname = 'localhost';

/*** mysql username ***/
$username = 'root';

/*** mysql password ***/
$password = '';

try {
    $dbh = new PDO("mysql:host=$hostname;dbname=test", $username, $password);
    /*** echo a message saying we have connected ***/
    echo 'Connected to database';
    }
catch(PDOException $e)
    {
    echo $e->getMessage();
    }


$matches = array('1');
$count = count($matches);
for($i = 0; $i < $count; ++$i) {
    $values[] = '?';
}

// INSERT INTO DATABASE
$sql = "INSERT INTO hashes (hash) VALUES (" . implode(', ', $values) . ") ON DUPLICATE KEY UPDATE hash='hash'";
$stmt = $dbh->prepare($sql);
$data = $stmt->execute($matches);

//Error reporting if something went wrong...
var_dump($dbh->errorInfo());

?>

You will need to adapt it a little.

Table structure I used is here:

CREATE TABLE IF NOT EXISTS `hashes` (
  `hashid` int(11) NOT NULL AUTO_INCREMENT,
  `hash` varchar(250) NOT NULL,
  PRIMARY KEY (`hashid`),
  UNIQUE KEY `hash1` (`hash`)
) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;

Code was run on my XAMPP Server which is using PHP 5.3.8 with MySQL 5.5.16.

I hope this helps.

Terminating a script in PowerShell

I used this for a reruning of a program. I don't know if it would help, but it is a simple if statement requiring only two different entry's. It worked in powershell for me.

$rerun = Read-Host "Rerun report (y/n)?"

if($rerun -eq "y") { Show-MemoryReport }
if($rerun -eq "n") { Exit }

Don't know if this helps, but i believe this would be along the lines of terminating a program after you have run it. However in this case, every defined input requires a listed and categorized output. You could also have the exit call up a new prompt line and terminate the program that way.

jQuery Popup Bubble/Tooltip

ColorTip is the most beautiful i've ever seen

Unlocking tables if thread is lost

how will I know that some tables are locked?

You can use SHOW OPEN TABLES command to view locked tables.

how do I unlock tables manually?

If you know the session ID that locked tables - 'SELECT CONNECTION_ID()', then you can run KILL command to terminate session and unlock tables.

Radio buttons not checked in jQuery

if ($("input").is(":not(:checked)"))

AFAIK, this should work, tested against the latest stable jQuery (1.2.6).

jQuery object equality

If you still don't know, you can get back the original object by:

alert($("#deviceTypeRoot")[0] == $("#deviceTypeRoot")[0]); //True
alert($("#deviceTypeRoot")[0] === $("#deviceTypeRoot")[0]);//True

because $("#deviceTypeRoot") also returns an array of objects which the selector has selected.

jQuery / Javascript code check, if not undefined

I generally like the shorthand version:

if (!!wlocation) { window.location = wlocation; }

disable horizontal scroll on mobile web

I had the same issue. Adding maximum-scale=1 fixed it:

OLD: <meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">

NEW: <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">

P.S. Also I have been using commas between values. But it seems to work with semi-colon as well.

What does the question mark operator mean in Ruby?

It's a convention in Ruby that methods that return boolean values end in a question mark. There's no more significance to it than that.

How to generate Javadoc HTML files in Eclipse?

This is a supplement answer related to the OP:

An easy and reliable solution to add Javadocs comments in Eclipse:

  1. Go to Help > Eclipse Marketplace....
  2. Find "JAutodoc".
  3. Install it and restart Eclipse.

To use this tool, right-click on class and click on JAutodoc.

Nullable types: better way to check for null or zero in c#

This is really just an expansion of Freddy Rios' accepted answer only using Generics.

public static bool IsNullOrDefault<T>(this Nullable<T> value) where T : struct
{
    return default(T).Equals( value.GetValueOrDefault() );
}

public static bool IsValue<T>(this Nullable<T> value, T valueToCheck) where T : struct
{
    return valueToCheck.Equals((value ?? valueToCheck));
}

NOTE we don't need to check default(T) for null since we are dealing with either value types or structs! This also means we can safely assume T valueToCheck will not be null; Remember here that T? is shorthand Nullable<T> so by adding the extension to Nullable<T> we get the method in int?, double?, bool? etc.

Examples:

double? x = null;
x.IsNullOrDefault(); //true

int? y = 3;
y.IsNullOrDefault(); //false

bool? z = false;
z.IsNullOrDefault(); //true

Notepad++ - How can I replace blank lines

This will remove any number of blank lines

CTRL + H to replace

Select Extended search mode

replace all \r\n with (space)

then switch to regular expression and replace all \s+ with \n

How to tag docker image with docker-compose

It seems the docs/tool have been updated and you can now add the image tag to your script. This was successful for me.

Example:

version: '2'
services:

  baggins.api.rest:
    image: my.image.name:rc2
    build:
      context: ../..
      dockerfile: app/Docker/Dockerfile.release
    ports:
      ...

https://docs.docker.com/compose/compose-file/#build

Transform only one axis to log10 scale with ggplot2

The simplest is to just give the 'trans' (formerly 'formatter' argument the name of the log function:

m + geom_boxplot() + scale_y_continuous(trans='log10')

EDIT: Or if you don't like that, then either of these appears to give different but useful results:

m <- ggplot(diamonds, aes(y = price, x = color), log="y")
m + geom_boxplot() 
m <- ggplot(diamonds, aes(y = price, x = color), log10="y")
m + geom_boxplot()

EDIT2 & 3: Further experiments (after discarding the one that attempted successfully to put "$" signs in front of logged values):

fmtExpLg10 <- function(x) paste(round_any(10^x/1000, 0.01) , "K $", sep="")
ggplot(diamonds, aes(color, log10(price))) + 
  geom_boxplot() + 
  scale_y_continuous("Price, log10-scaling", trans = fmtExpLg10)

alt text

Note added mid 2017 in comment about package syntax change:

scale_y_continuous(formatter = 'log10') is now scale_y_continuous(trans = 'log10') (ggplot2 v2.2.1)

How to generate UML diagrams (especially sequence diagrams) from Java code?

EDIT: If you're a designer then Papyrus is your best choice it's very advanced and full of features, but if you just want to sketch out some UML diagrams and easy installation then ObjectAid is pretty cool and it doesn't require any plugins I just installed it over Eclipse-Java EE and works great !.


UPDATE Oct 11th, 2013

My original post was in June 2012 a lot of things have changed many tools has grown and others didn't. Since I'm going back to do some modeling and also getting some replies to the post I decided to install papyrus again and will investigate other possible UML modeling solutions again. UML generation (with synchronization feature) is really important not to software designer but to the average developer.

I wish papyrus had straightforward way to Reverse Engineer classes into UML class diagram and It would be super cool if that reverse engineering had a synchronization feature, but unfortunately papyrus project is full of features and I think developers there have already much at hand since also many actions you do over papyrus might not give you any response and just nothing happens but that's out of this question scope anyway.

The Answer (Oct 11th, 2013)

Tools

  1. Download Papyrus
  2. Go to Help -> Install New Software...
  3. In the Work with: drop-down, select --All Available Sites--
  4. In the filter, type in Papyrus
  5. After installation finishes restart Eclipse
  6. Repeat steps 1-3 and this time, install Modisco

Steps

  1. In your java project (assume it's called MyProject) create a folder e.g UML
  2. Right click over the project name -> Discovery -> Discoverer -> Discover Java and inventory model from java project, a file called MyProject_kdm.xmi will be generated. enter image description here
  3. Right click project name file --> new --> papyrus model -> and call it MyProject.
  4. Move the three generated files MyProject.di , MyProject.notation, MyProject.uml to the UML folder
  5. Right click on MyProject_kdm.xmi -> Discovery -> Discoverer -> Discover UML model from KDM code again you'll get a property dialog set the serialization prop to TRUE to generate a file named MyProject.uml enter image description here

  6. Move generated MyProject.uml which was generated at root, to UML folder, Eclipse will ask you If you wanted to replace it click yes. What we did in here was that we replaced an empty model with a generated one.

  7. ALT+W -> show view -> papyrus -> model explorer

  8. In that view, you'll find your classes like in the picture enter image description here

  9. In the view Right click root model -> New diagram enter image description here

  10. Then start grabbing classes to the diagram from the view

Some features

  • To show the class elements (variables, functions etc) Right click on any class -> Filters -> show/hide contents Voila !!

  • You can have default friendly color settings from Window -> pereferences -> papyrus -> class diagram

  • one very important setting is Arrange when you drop the classes they get a cramped right click on any empty space at a class diagram and click Arrange All

  • Arrows in the model explorer view can be grabbed to the diagram to show generalization, realization etc

  • After all of that your settings will show diagrams like enter image description here

  • Synchronization isn't available as far as I know you'll need to manually import any new classes.

That's all, And don't buy commercial products unless you really need it, papyrus is actually great and sophisticated instead donate or something.

Disclaimer: I've no relation to the papyrus people, in fact, I didn't like papyrus at first until I did lots of research and experienced it with some patience. And will get back to this post again when I try other free tools.

Promise.all().then() resolve?

But that doesn't seem like the proper way to do it..

That is indeed the proper way to do it (or at least a proper way to do it). This is a key aspect of promises, they're a pipeline, and the data can be massaged by the various handlers in the pipeline.

Example:

_x000D_
_x000D_
const promises = [_x000D_
  new Promise(resolve => setTimeout(resolve, 0, 1)),_x000D_
  new Promise(resolve => setTimeout(resolve, 0, 2))_x000D_
];_x000D_
Promise.all(promises)_x000D_
  .then(data => {_x000D_
    console.log("First handler", data);_x000D_
    return data.map(entry => entry * 10);_x000D_
  })_x000D_
  .then(data => {_x000D_
    console.log("Second handler", data);_x000D_
  });
_x000D_
_x000D_
_x000D_

(catch handler omitted for brevity. In production code, always either propagate the promise, or handle rejection.)

The output we see from that is:

First handler [1,2]
Second handler [10,20]

...because the first handler gets the resolution of the two promises (1 and 2) as an array, and then creates a new array with each of those multiplied by 10 and returns it. The second handler gets what the first handler returned.

If the additional work you're doing is synchronous, you can also put it in the first handler:

Example:

_x000D_
_x000D_
const promises = [_x000D_
  new Promise(resolve => setTimeout(resolve, 0, 1)),_x000D_
  new Promise(resolve => setTimeout(resolve, 0, 2))_x000D_
];_x000D_
Promise.all(promises)_x000D_
  .then(data => {_x000D_
    console.log("Initial data", data);_x000D_
    data = data.map(entry => entry * 10);_x000D_
    console.log("Updated data", data);_x000D_
    return data;_x000D_
  });
_x000D_
_x000D_
_x000D_

...but if it's asynchronous you won't want to do that as it ends up getting nested, and the nesting can quickly get out of hand.

Modifying a file inside a jar

Extract jar file for ex. with winrar and use CAVAJ:

Cavaj Java Decompiler is a graphical freeware utility that reconstructs Java source code from CLASS files.

here is video tutorial if you need: https://www.youtube.com/watch?v=ByLUeem7680

How to download a file with Node.js (without using third-party libraries)?

You can use https://github.com/douzi8/ajax-request#download

request.download('http://res.m.ctrip.com/html5/Content/images/57.png', 
  function(err, res, body) {}
);

Permutations between two lists of unequal length

The better answers to this only work for specific lengths of lists that are provided.

Here's a version that works for any lengths of input. It also makes the algorithm clear in terms of the mathematical concepts of combination and permutation.

from itertools import combinations, permutations
list1 = ['1', '2']
list2 = ['A', 'B', 'C']

num_elements = min(len(list1), len(list2))
list1_combs = list(combinations(list1, num_elements))
list2_perms = list(permutations(list2, num_elements))
result = [
  tuple(zip(perm, comb))
  for comb in list1_combs
  for perm in list2_perms
]

for idx, ((l11, l12), (l21, l22)) in enumerate(result):
  print(f'{idx}: {l11}{l12} {l21}{l22}')

This outputs:

0: A1 B2
1: A1 C2
2: B1 A2
3: B1 C2
4: C1 A2
5: C1 B2

How to hide Android soft keyboard on EditText

   public class NonKeyboardEditText extends AppCompatEditText {

    public NonKeyboardEditText(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    public boolean onCheckIsTextEditor() {
        return false;
    }
}

and add

NonKeyboardEditText.setTextIsSelectable(true);

Preventing HTML and Script injections in Javascript

A one-liner:

var encodedMsg = $('<div />').text(message).html();

See it work:

https://jsfiddle.net/TimothyKanski/wnt8o12j/

Warning: mysql_connect(): Access denied for user 'root'@'localhost' (using password: YES)

try $conn = mysql_connect("localhost", "root") or $conn = mysql_connect("localhost", "root", "")

get client time zone from browser

I used an approach similar to the one taken by Josh Fraser, which determines the browser time offset from UTC and whether it recognizes DST or not (but somewhat simplified from his code):

var ClientTZ = {
    UTCoffset:  0,          // Browser time offset from UTC in minutes
    UTCoffsetT: '+0000S',   // Browser time offset from UTC in '±hhmmD' form
    hasDST:     false,      // Browser time observes DST

    // Determine browser's timezone and DST
    getBrowserTZ: function () {
        var self = ClientTZ;

        // Determine UTC time offset
        var now = new Date();
        var date1 = new Date(now.getFullYear(), 1-1, 1, 0, 0, 0, 0);    // Jan
        var diff1 = -date1.getTimezoneOffset();
        self.UTCoffset = diff1;

        // Determine DST use
        var date2 = new Date(now.getFullYear(), 6-1, 1, 0, 0, 0, 0);    // Jun
        var diff2 = -date2.getTimezoneOffset();
        if (diff1 != diff2) {
            self.hasDST = true;
            if (diff1 - diff2 >= 0)
                self.UTCoffset = diff2;     // East of GMT
        }

        // Convert UTC offset to ±hhmmD form
        diff2 = (diff1 < 0 ? -diff1 : diff1) / 60;
        var hr = Math.floor(diff2);
        var min = diff2 - hr;
        diff2 = hr * 100 + min * 60;
        self.UTCoffsetT = (diff1 < 0 ? '-' : '+') + (hr < 10 ? '0' : '') + diff2.toString() + (self.hasDST ? 'D' : 'S');

        return self.UTCoffset;
    }
};

// Onload
ClientTZ.getBrowserTZ();

Upon loading, the ClientTZ.getBrowserTZ() function is executed, which sets:

  • ClientTZ.UTCoffset to the browser time offset from UTC in minutes (e.g., CST is -360 minutes, which is -6.0 hours from UTC);
  • ClientTZ.UTCoffsetT to the offset in the form '±hhmmD' (e.g., '-0600D'), where the suffix is D for DST and S for standard (non-DST);
  • ClientTZ.hasDST (to true or false).

The ClientTZ.UTCoffset is provided in minutes instead of hours, because some timezones have fractional hourly offsets (e.g., +0415).

The intent behind ClientTZ.UTCoffsetT is to use it as a key into a table of timezones (not provided here), such as for a drop-down <select> list.

Create a dictionary with list comprehension

Just to throw in another example. Imagine you have the following list:

nums = [4,2,2,1,3]

and you want to turn it into a dict where the key is the index and value is the element in the list. You can do so with the following line of code:

{index:nums[index] for index in range(0,len(nums))}

Interface defining a constructor signature?

you don't.

the constructor is part of the class that can implement an interface. The interface is just a contract of methods the class must implement.

C#: HttpClient with POST parameters

A cleaner alternative would be to use a Dictionary to handle parameters. They are key-value pairs after all.

private static readonly HttpClient httpclient;

static MyClassName()
{
    // HttpClient is intended to be instantiated once and re-used throughout the life of an application. 
    // Instantiating an HttpClient class for every request will exhaust the number of sockets available under heavy loads. 
    // This will result in SocketException errors.
    // https://docs.microsoft.com/en-us/dotnet/api/system.net.http.httpclient?view=netframework-4.7.1
    httpclient = new HttpClient();    
} 

var url = "http://myserver/method";
var parameters = new Dictionary<string, string> { { "param1", "1" }, { "param2", "2" } };
var encodedContent = new FormUrlEncodedContent (parameters);

var response = await httpclient.PostAsync (url, encodedContent).ConfigureAwait (false);
if (response.StatusCode == HttpStatusCode.OK) {
    // Do something with response. Example get content:
    // var responseContent = await response.Content.ReadAsStringAsync ().ConfigureAwait (false);
}

Also dont forget to Dispose() httpclient, if you dont use the keyword using

As stated in the Remarks section of the HttpClient class in the Microsoft docs, HttpClient should be instantiated once and re-used.

Edit:

You may want to look into response.EnsureSuccessStatusCode(); instead of if (response.StatusCode == HttpStatusCode.OK).

You may want to keep your httpclient and dont Dispose() it. See: Do HttpClient and HttpClientHandler have to be disposed?

Edit:

Do not worry about using .ConfigureAwait(false) in .NET Core. For more details look at https://blog.stephencleary.com/2017/03/aspnetcore-synchronization-context.html

Batch file script to zip files

I like PodTech.io's answer to achieve this without additional tools. For me, it did not run out of the box, so I had to slightly change it. I am not sure if the command wScript.Sleep 12000 (12 sec delay) in the original script is required or not, so I kept it.

Here's the modified script Zip.cmd based on his answer, which works fine on my end:

@echo off   
if "%1"=="" goto end

setlocal
set TEMPDIR=%TEMP%\ZIP
set FILETOZIP=%1
set OUTPUTZIP=%2.zip
if "%2"=="" set OUTPUTZIP=%1.zip

:: preparing VBS script
echo Set objArgs = WScript.Arguments > _zipIt.vbs
echo InputFolder = objArgs(0) >> _zipIt.vbs
echo ZipFile = objArgs(1) >> _zipIt.vbs
echo Set fso = WScript.CreateObject("Scripting.FileSystemObject") >> _zipIt.vbs
echo Set objZipFile = fso.CreateTextFile(ZipFile, True) >> _zipIt.vbs
echo objZipFile.Write "PK" ^& Chr(5) ^& Chr(6) ^& String(18, vbNullChar) >> _zipIt.vbs
echo objZipFile.Close >> _zipIt.vbs
echo Set objShell = WScript.CreateObject("Shell.Application") >> _zipIt.vbs
echo Set source = objShell.NameSpace(InputFolder).Items >> _zipIt.vbs
echo Set objZip = objShell.NameSpace(fso.GetAbsolutePathName(ZipFile)) >> _zipIt.vbs
echo if not (objZip is nothing) then  >> _zipIt.vbs
echo    objZip.CopyHere(source) >> _zipIt.vbs
echo    wScript.Sleep 12000 >> _zipIt.vbs
echo end if >> _zipIt.vbs

@ECHO Zipping, please wait...
mkdir %TEMPDIR%
xcopy /y /s %FILETOZIP% %TEMPDIR%
WScript _zipIt.vbs  %TEMPDIR%  %OUTPUTZIP%
del _zipIt.vbs
rmdir /s /q  %TEMPDIR%

@ECHO ZIP Completed.
:end

Usage:

  • One parameter (no wildcards allowed here):

    Zip FileToZip.txt

    will create FileToZip.txt.zip in the same folder containing the zipped file FileToZip.txt.

  • Two parameters (optionally with wildcards for the first parameter), e.g.

    Zip *.cmd Scripts

    creates Scripts.zip in the same folder containing all matching *.cmd files.


Note: If you want to debug the VBS script, check out this hint, it describes how to activate the debugger to go through it step by step.

Laravel - Form Input - Multiple select for a one to many relationship

A multiple select is really just a select with a multiple attribute. With that in mind, it should be as easy as...

Form::select('sports[]', $sports, null, array('multiple'))

The first parameter is just the name, but post-fixing it with the [] will return it as an array when you use Input::get('sports').

The second parameter is an array of selectable options.

The third parameter is an array of options you want pre-selected.

The fourth parameter is actually setting this up as a multiple select dropdown by adding the multiple property to the actual select element..

Compare two files and write it to "match" and "nomatch" files

//STEP01   EXEC SORT90MB                        
//SORTJNF1 DD DSN=INPUTFILE1,   
//            DISP=SHR                          
//SORTJNF2 DD DSN=INPUTFILE2,   
//            DISP=SHR                          
//SORTOUT  DD DSN=MISMATCH_OUTPUT_FILE, 
//            DISP=(,CATLG,DELETE),             
//            UNIT=TAPE,                        
//            DCB=(RECFM=FB,BLKSIZE=0),         
//            DSORG=PS                          
//SYSOUT   DD SYSOUT=*                          
//SYSIN    DD *                                 
  JOINKEYS FILE=F1,FIELDS=(1,79,A)              
  JOINKEYS FILE=F2,FIELDS=(1,79,A)              
  JOIN UNPAIRED,F1,ONLY                         
  SORT FIELDS=COPY                              
/*                                              

How to set variable from a SQL query?

Use TOP 1 if the query returns multiple rows.

SELECT TOP 1 @ModelID = m.modelid 
  FROM MODELS m
 WHERE m.areaid = 'South Coast'

TypeError: a bytes-like object is required, not 'str' in python and CSV

I had the same issue with Python3. My code was writing into io.BytesIO().

Replacing with io.StringIO() solved.

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

Directory.GetFiles(@"C:\Users\AliBayat","*",SearchOption.AllDirectories)
.Select (d => new FileInfo(d))
.Select (d => new { Directory = d.DirectoryName,FileSize = d.Length} )
.ToLookup (d => d.Directory )
.Select (d => new { Directory = d.Key,TotalSizeInMB =Math.Round(d.Select (x =>x.FileSize)
.Sum () /Math.Pow(1024.0,2),2)})
.OrderByDescending (d => d.TotalSizeInMB).ToList();

Calling GetFiles with SearchOption.AllDirectories returns the full name of all the files in all the subdirectories of the specified directory. The OS represents the size of files in bytes. You can retrieve the file’s size from its Length property. Dividing it by 1024 raised to the power of 2 gives you the size of the file in megabytes. Because a directory/folder can contain many files, d.Select(x => x.FileSize) returns a collection of file sizes measured in megabytes. The final call to Sum() finds the total size of the files in the specified directory.

Update: the filterMask="." does not work with files without extension

Error: EACCES: permission denied

node recommends executing following:

 sudo chown -R $USER:$(id -gn $USER) /home/venkatesh/.config

If you execute

npm config

You will see something like this

¦                   npm update check failed                   ¦
¦             Try running with sudo or get access             ¦
¦            to the local update config store via             ¦
¦ sudo chown -R $USER:$(id -gn $USER) /home/venkatesh/.config ¦

It worked for me.

org.postgresql.util.PSQLException: FATAL: sorry, too many clients already

We don't know what server.properties file is that, we neither know what SimocoPoolSize means (do you?)

Let's guess you are using some custom pool of database connections. Then, I guess the problem is that your pool is configured to open 100 or 120 connections, but you Postgresql server is configured to accept MaxConnections=90 . These seem conflictive settings. Try increasing MaxConnections=120.

But you should first understand your db layer infrastructure, know what pool are you using, if you really need so many open connections in the pool. And, specially, if you are gracefully returning the opened connections to the pool

How do I create a dynamic key to be added to a JavaScript object variable

Square brackets:

jsObj['key' + i] = 'example' + 1;

In JavaScript, all arrays are objects, but not all objects are arrays. The primary difference (and one that's pretty hard to mimic with straight JavaScript and plain objects) is that array instances maintain the length property so that it reflects one plus the numeric value of the property whose name is numeric and whose value, when converted to a number, is the largest of all such properties. That sounds really weird, but it just means that given an array instance, the properties with names like "0", "5", "207", and so on, are all treated specially in that their existence determines the value of length. And, on top of that, the value of length can be set to remove such properties. Setting the length of an array to 0 effectively removes all properties whose names look like whole numbers.

OK, so that's what makes an array special. All of that, however, has nothing at all to do with how the JavaScript [ ] operator works. That operator is an object property access mechanism which works on any object. It's important to note in that regard that numeric array property names are not special as far as simple property access goes. They're just strings that happen to look like numbers, but JavaScript object property names can be any sort of string you like.

Thus, the way the [ ] operator works in a for loop iterating through an array:

for (var i = 0; i < myArray.length; ++i) {
  var value = myArray[i]; // property access
  // ...
}

is really no different from the way [ ] works when accessing a property whose name is some computed string:

var value = jsObj["key" + i];

The [ ] operator there is doing precisely the same thing in both instances. The fact that in one case the object involved happens to be an array is unimportant, in other words.

When setting property values using [ ], the story is the same except for the special behavior around maintaining the length property. If you set a property with a numeric key on an array instance:

myArray[200] = 5;

then (assuming that "200" is the biggest numeric property name) the length property will be updated to 201 as a side-effect of the property assignment. If the same thing is done to a plain object, however:

myObj[200] = 5;

there's no such side-effect. The property called "200" of both the array and the object will be set to the value 5 in otherwise the exact same way.

One might think that because that length behavior is kind-of handy, you might as well make all objects instances of the Array constructor instead of plain objects. There's nothing directly wrong about that (though it can be confusing, especially for people familiar with some other languages, for some properties to be included in the length but not others). However, if you're working with JSON serialization (a fairly common thing), understand that array instances are serialized to JSON in a way that only involves the numerically-named properties. Other properties added to the array will never appear in the serialized JSON form. So for example:

var obj = [];
obj[0] = "hello world";
obj["something"] = 5000;

var objJSON = JSON.stringify(obj);

the value of "objJSON" will be a string containing just ["hello world"]; the "something" property will be lost.

ES2015:

If you're able to use ES6 JavaScript features, you can use Computed Property Names to handle this very easily:

var key = 'DYNAMIC_KEY',
    obj = {
        [key]: 'ES6!'
    };

console.log(obj);
// > { 'DYNAMIC_KEY': 'ES6!' }

How to create a new instance from a class object in Python

If you have a module with a class you want to import, you can do it like this.

module = __import__(filename)
instance = module.MyClass()

If you do not know what the class is named, you can iterate through the classes available from a module.

import inspect
module = __import__(filename)
for c in module.__dict__.values():
    if inspect.isclass(c):
        # You may need do some additional checking to ensure 
        # it's the class you want
        instance = c()

How to remove specific value from array using jQuery

I had a similar task where I needed to delete multiple objects at once based on a property of the objects in the array.

So after a few iterations I end up with:

list = $.grep(list, function (o) { return !o.IsDeleted });

How to delete selected text in the vi editor

If you want to remove all lines in a file from your current line number, use dG, it will delete all lines (shift g) mean end of file

Angularjs if-then-else construction in expression

You can easily use ng-show such as :

    <div ng-repeater="item in items">
        <div>{{item.description}}</div>
        <div ng-show="isExists(item)">available</div>
        <div ng-show="!isExists(item)">oh no, you don't have it</div>
    </div>

For more complex tests, you can use ng-switch statements :

    <div ng-repeater="item in items">
        <div>{{item.description}}</div>
        <div ng-switch on="isExists(item)">
            <span ng-switch-when="true">Available</span>
            <span ng-switch-default>oh no, you don't have it</span>
        </div>
    </div>

How to change Screen buffer size in Windows Command Prompt from batch script

I was just searching for an answer to this exact question, come to find out the command itself adjusts the buffer!

mode con:cols=140 lines=70

The lines=70 part actually adjusts the Height in the 'Screen Buffer Size' setting, NOT the Height in the 'Window Size' setting.

Easily proven by running the command with a setting for 'lines=2500' (or whatever buffer you want) and then check the 'Properties' of the window, you'll see that indeed the buffer is now set to 2500.

My batch script ends up looking like this:

@echo off
cmd "mode con:cols=140 lines=2500"

What is the error "Every derived table must have its own alias" in MySQL?

I arrived here because I thought I should check in SO if there are adequate answers, after a syntax error that gave me this error, or if I could possibly post an answer myself.

OK, the answers here explain what this error is, so not much more to say, but nevertheless I will give my 2 cents using my words:

This error is caused by the fact that you basically generate a new table with your subquery for the FROM command.

That's what a derived table is, and as such, it needs to have an alias (actually a name reference to it).

So given the following hypothetical query:

SELECT id, key1
FROM (
    SELECT t1.ID id, t2.key1 key1, t2.key2 key2, t2.key3 key3
    FROM table1 t1 
    LEFT JOIN table2 t2 ON t1.id = t2.id
    WHERE t2.key3 = 'some-value'
) AS tt

So, at the end, the whole subquery inside the FROM command will produce the table that is aliased as tt and it will have the following columns id, key1, key2, key3.

So, then with the initial SELECT from that table we finally select the id and key1 from the tt.

AttributeError: 'list' object has no attribute 'encode'

You need to do encode on tmp[0], not on tmp.

tmp is not a string. It contains a (Unicode) string.

Try running type(tmp) and print dir(tmp) to see it for yourself.

How do I configure Apache 2 to run Perl CGI scripts?

There are two ways to handle CGI scripts, SetHandler and AddHandler.

SetHandler cgi-script

applies to all files in a given context, no matter how they are named, even index.html or style.css.

AddHandler cgi-script .pl

is similar, but applies to files ending in .pl, in a given context. You may choose another extension or several, if you like.

Additionally, the CGI module must be loaded and Options +ExecCGI configured. To activate the module, issue

a2enmod cgi

and restart or reload Apache. Finally, the Perl CGI script must be executable. So the execute bits must be set

chmod a+x script.pl

and it should start with

#! /usr/bin/perl

as its first line.


When you use SetHandler or AddHandler (and Options +ExecCGI) outside of any directive, it is applied globally to all files. But you may restrict the context to a subset by enclosing these directives inside, e.g. Directory

<Directory /path/to/some/cgi-dir>
    SetHandler cgi-script
    Options +ExecCGI
</Directory>

Now SetHandler applies only to the files inside /path/to/some/cgi-dir instead of all files of the web site. Same is with AddHandler inside a Directory or Location directive, of course. It then applies to the files inside /path/to/some/cgi-dir, ending in .pl.

How to change the opacity (alpha, transparency) of an element in a canvas element after it has been drawn?

If you use jCanvas library you can use opacity property when drawing. If you need fade effect on top of that, simply redraw with different values.

How to deal with bad_alloc in C++?

You can catch it like any other exception:

try {
  foo();
}
catch (const std::bad_alloc&) {
  return -1;
}

Quite what you can usefully do from this point is up to you, but it's definitely feasible technically.



In general you cannot, and should not try, to respond to this error. bad_alloc indicates that a resource cannot be allocated because not enough memory is available. In most scenarios your program cannot hope to cope with that, and terminating soon is the only meaningful behaviour.

Worse, modern operating systems often over-allocate: on such systems, malloc and new can return a valid pointer even if there is not enough free memory left – std::bad_alloc will never be thrown, or is at least not a reliable sign of memory exhaustion. Instead, attempts to access the allocated memory will then result in a segmentation fault, which is not catchable (you can handle the segmentation fault signal, but you cannot resume the program afterwards).

The only thing you could do when catching std::bad_alloc is to perhaps log the error, and try to ensure a safe program termination by freeing outstanding resources (but this is done automatically in the normal course of stack unwinding after the error gets thrown if the program uses RAII appropriately).

In certain cases, the program may attempt to free some memory and try again, or use secondary memory (= disk) instead of RAM but these opportunities only exist in very specific scenarios with strict conditions:

  1. The application must ensure that it runs on a system that does not overcommit memory, i.e. it signals failure upon allocation rather than later.
  2. The application must be able to free memory immediately, without any further accidental allocations in the meantime.

It’s exceedingly rare that applications have control over point 1 — userspace applications never do, it’s a system-wide setting that requires root permissions to change.1

OK, so let’s assume you’ve fixed point 1. What you can now do is for instance use a LRU cache for some of your data (probably some particularly large business objects that can be regenerated or reloaded on demand). Next, you need to put the actual logic that may fail into a function that supports retry — in other words, if it gets aborted, you can just relaunch it:

lru_cache<widget> widget_cache;

double perform_operation(int widget_id) {
    std::optional<widget> maybe_widget = widget_cache.find_by_id(widget_id);
    if (not maybe_widget) {
        maybe_widget = widget_cache.store(widget_id, load_widget_from_disk(widget_id));
    }
    return maybe_widget->frobnicate();
}

…

for (int num_attempts = 0; num_attempts < MAX_NUM_ATTEMPTS; ++num_attempts) {
    try {
        return perform_operation(widget_id);
    } catch (std::bad_alloc const&) {
        if (widget_cache.empty()) throw; // memory error elsewhere.
        widget_cache.remove_oldest();
    }
}

// Handle too many failed attempts here.

But even here, using std::set_new_handler instead of handling std::bad_alloc provides the same benefit and would be much simpler.


1 If you’re creating an application that does control point 1, and you’re reading this answer, please shoot me an email, I’m genuinely curious about your circumstances.


What is the C++ Standard specified behavior of new in c++?

The usual notion is that if new operator cannot allocate dynamic memory of the requested size, then it should throw an exception of type std::bad_alloc.
However, something more happens even before a bad_alloc exception is thrown:

C++03 Section 3.7.4.1.3: says

An allocation function that fails to allocate storage can invoke the currently installed new_handler(18.4.2.2), if any. [Note: A program-supplied allocation function can obtain the address of the currently installed new_handler using the set_new_handler function (18.4.2.3).] If an allocation function declared with an empty exception-specification (15.4), throw(), fails to allocate storage, it shall return a null pointer. Any other allocation function that fails to allocate storage shall only indicate failure by throw-ing an exception of class std::bad_alloc (18.4.2.1) or a class derived from std::bad_alloc.

Consider the following code sample:

#include <iostream>
#include <cstdlib>

// function to call if operator new can't allocate enough memory or error arises
void outOfMemHandler()
{
    std::cerr << "Unable to satisfy request for memory\n";

    std::abort();
}

int main()
{
    //set the new_handler
    std::set_new_handler(outOfMemHandler);

    //Request huge memory size, that will cause ::operator new to fail
    int *pBigDataArray = new int[100000000L];

    return 0;
}

In the above example, operator new (most likely) will be unable to allocate space for 100,000,000 integers, and the function outOfMemHandler() will be called, and the program will abort after issuing an error message.

As seen here the default behavior of new operator when unable to fulfill a memory request, is to call the new-handler function repeatedly until it can find enough memory or there is no more new handlers. In the above example, unless we call std::abort(), outOfMemHandler() would be called repeatedly. Therefore, the handler should either ensure that the next allocation succeeds, or register another handler, or register no handler, or not return (i.e. terminate the program). If there is no new handler and the allocation fails, the operator will throw an exception.

What is the new_handler and set_new_handler?

new_handler is a typedef for a pointer to a function that takes and returns nothing, and set_new_handler is a function that takes and returns a new_handler.

Something like:

typedef void (*new_handler)();
new_handler set_new_handler(new_handler p) throw();

set_new_handler's parameter is a pointer to the function operator new should call if it can't allocate the requested memory. Its return value is a pointer to the previously registered handler function, or null if there was no previous handler.

How to handle out of memory conditions in C++?

Given the behavior of newa well designed user program should handle out of memory conditions by providing a proper new_handlerwhich does one of the following:

Make more memory available: This may allow the next memory allocation attempt inside operator new's loop to succeed. One way to implement this is to allocate a large block of memory at program start-up, then release it for use in the program the first time the new-handler is invoked.

Install a different new-handler: If the current new-handler can't make any more memory available, and of there is another new-handler that can, then the current new-handler can install the other new-handler in its place (by calling set_new_handler). The next time operator new calls the new-handler function, it will get the one most recently installed.

(A variation on this theme is for a new-handler to modify its own behavior, so the next time it's invoked, it does something different. One way to achieve this is to have the new-handler modify static, namespace-specific, or global data that affects the new-handler's behavior.)

Uninstall the new-handler: This is done by passing a null pointer to set_new_handler. With no new-handler installed, operator new will throw an exception ((convertible to) std::bad_alloc) when memory allocation is unsuccessful.

Throw an exception convertible to std::bad_alloc. Such exceptions are not be caught by operator new, but will propagate to the site originating the request for memory.

Not return: By calling abort or exit.

Creating custom function in React component

With React Functional way

import React, { useEffect } from "react";
import ReactDOM from "react-dom";
import Button from "@material-ui/core/Button";

const App = () => {
  const saySomething = (something) => {
    console.log(something);
  };
  useEffect(() => {
    saySomething("from useEffect");
  });
  const handleClick = (e) => {
    saySomething("element clicked");
  };
  return (
    <Button variant="contained" color="primary" onClick={handleClick}>
      Hello World
    </Button>
  );
};

ReactDOM.render(<App />, document.querySelector("#app"));

https://codesandbox.io/s/currying-meadow-gm9g0

here-document gives 'unexpected end of file' error

The line that starts or ends the here-doc probably has some non-printable or whitespace characters (for example, carriage return) which means that the second "EOF" does not match the first, and doesn't end the here-doc like it should. This is a very common error, and difficult to detect with just a text editor. You can make non-printable characters visible for example with cat:

cat -A myfile.sh

Once you see the output from cat -A the solution will be obvious: remove the offending characters.

How to use BeanUtils.copyProperties?

As you can see in the below source code, BeanUtils.copyProperties internally uses reflection and there's additional internal cache lookup steps as well which is going to add cost wrt performance

 private static void copyProperties(Object source, Object target, @Nullable Class<?> editable,
                @Nullable String... ignoreProperties) throws BeansException {

            Assert.notNull(source, "Source must not be null");
            Assert.notNull(target, "Target must not be null");

            Class<?> actualEditable = target.getClass();
            if (editable != null) {
                if (!editable.isInstance(target)) {
                    throw new IllegalArgumentException("Target class [" + target.getClass().getName() +
                            "] not assignable to Editable class [" + editable.getName() + "]");
                }
                actualEditable = editable;
            }
            **PropertyDescriptor[] targetPds = getPropertyDescriptors(actualEditable);**
            List<String> ignoreList = (ignoreProperties != null ? Arrays.asList(ignoreProperties) : null);

            for (PropertyDescriptor targetPd : targetPds) {
                Method writeMethod = targetPd.getWriteMethod();
                if (writeMethod != null && (ignoreList == null || !ignoreList.contains(targetPd.getName()))) {
                    PropertyDescriptor sourcePd = getPropertyDescriptor(source.getClass(), targetPd.getName());
                    if (sourcePd != null) {
                        Method readMethod = sourcePd.getReadMethod();
                        if (readMethod != null &&
                                ClassUtils.isAssignable(writeMethod.getParameterTypes()[0], readMethod.getReturnType())) {
                            try {
                                if (!Modifier.isPublic(readMethod.getDeclaringClass().getModifiers())) {
                                    readMethod.setAccessible(true);
                                }
                                Object value = readMethod.invoke(source);
                                if (!Modifier.isPublic(writeMethod.getDeclaringClass().getModifiers())) {
                                    writeMethod.setAccessible(true);
                                }
                                writeMethod.invoke(target, value);
                            }
                            catch (Throwable ex) {
                                throw new FatalBeanException(
                                        "Could not copy property '" + targetPd.getName() + "' from source to target", ex);
                            }
                        }
                    }
                }
            }
        }

So it's better to use plain setters given the cost reflection

Convert char * to LPWSTR

I'm using the following in VC++ and it works like a charm for me.

CA2CT(charText)

Oracle SQL : timestamps in where clause

For everyone coming to this thread with fractional seconds in your timestamp use:

to_timestamp('2018-11-03 12:35:20.419000', 'YYYY-MM-DD HH24:MI:SS.FF')

A field initializer cannot reference the nonstatic field, method, or property

You need to put that code into the constructor of your class:

private Reminders reminder = new Reminders();
private dynamic defaultReminder;

public YourClass()
{
    defaultReminder = reminder.TimeSpanText[TimeSpan.FromMinutes(15)];
}

The reason is that you can't use one instance variable to initialize another one using a field initializer.

Find duplicate entries in a column

Using:

  SELECT t.ctn_no
    FROM YOUR_TABLE t
GROUP BY t.ctn_no
  HAVING COUNT(t.ctn_no) > 1

...will show you the ctn_no value(s) that have duplicates in your table. Adding criteria to the WHERE will allow you to further tune what duplicates there are:

  SELECT t.ctn_no
    FROM YOUR_TABLE t
   WHERE t.s_ind = 'Y'
GROUP BY t.ctn_no
  HAVING COUNT(t.ctn_no) > 1

If you want to see the other column values associated with the duplicate, you'll want to use a self join:

SELECT x.*
  FROM YOUR_TABLE x
  JOIN (SELECT t.ctn_no
          FROM YOUR_TABLE t
      GROUP BY t.ctn_no
        HAVING COUNT(t.ctn_no) > 1) y ON y.ctn_no = x.ctn_no

Angular 2 change event on every keypress

In my case, the solution is:

[ngModel]="X?.Y" (ngModelChange)="X.Y=$event"

Easy way to print Perl array? (with a little formatting)

Also, you may want to try Data::Dumper. Example:

use Data::Dumper;

# simple procedural interface
print Dumper($foo, $bar);

update package.json version automatically

To give a more up-to-date approach.

package.json

  "scripts": {
    "eslint": "eslint index.js",
    "pretest": "npm install",
    "test": "npm run eslint",
    "preversion": "npm run test",
    "version": "",
    "postversion": "git push && git push --tags && npm publish"
  }

Then you run it:

npm version minor --force -m "Some message to commit"

Which will:

  1. ... run tests ...

  2. change your package.json to a next minor version (e.g: 1.8.1 to 1.9.0)

  3. push your changes

  4. create a new git tag release and

  5. publish your npm package.

--force is to show who is the boss! Jokes aside see https://github.com/npm/npm/issues/8620

How to get only time from date-time C#

DateTime now = DateTime.Now;

now.ToLongDateString();    // Wednesday, January 2, 2019
now.ToLongTimeString();    // 2:33:59 PM
now.ToShortDateString();   // 1/2/2019
now.ToShortTimeString();   // 2:16 PM
now.ToString();            // 1/2/2019 2:33:59 PM

How to plot a function curve in R

plot has a plot.function method

plot(eq, 1, 1000)

Or

curve(eq, 1, 1000)

How do I return JSON without using a template in Django?

You could also check the request accept content type as specified in the rfc. That way you can render by default HTML and where your client accept application/jason you can return json in your response without a template being required

Merge two (or more) lists into one, in C# .NET

I've already commented it but I still think is a valid option, just test if in your environment is better one solution or the other. In my particular case, using source.ForEach(p => dest.Add(p)) performs better than the classic AddRange but I've not investigated why at the low level.

You can see an example code here: https://gist.github.com/mcliment/4690433

So the option would be:

var allProducts = new List<Product>(productCollection1.Count +
                                    productCollection2.Count +
                                    productCollection3.Count);

productCollection1.ForEach(p => allProducts.Add(p));
productCollection2.ForEach(p => allProducts.Add(p));
productCollection3.ForEach(p => allProducts.Add(p));

Test it to see if it works for you.

Disclaimer: I'm not advocating for this solution, I find Concat the most clear one. I just stated -in my discussion with Jon- that in my machine this case performs better than AddRange, but he says, with far more knowledge than I, that this does not make sense. There's the gist if you want to compare.

jQuery .live() vs .on() method for adding a click event after loading dynamic html

I know it's a little late for an answer, but I've created a polyfill for the .live() method. I've tested it in jQuery 1.11, and it seems to work pretty well. I know that we're supposed to implement the .on() method wherever possible, but in big projects, where it's not possible to convert all .live() calls to the equivalent .on() calls for whatever reason, the following might work:

if(jQuery && !jQuery.fn.live) {
    jQuery.fn.live = function(evt, func) {
        $('body').on(evt, this.selector, func);
    }
}

Just include it after you load jQuery and before you call live().

bundle install fails with SSL certificate verification error

You can download a list of CA certificates from curl's website at http://curl.haxx.se/ca/cacert.pem

Then set the SSL_CERT_FILE environment variable to tell Ruby to use it. For example, in Linux:

$ SSL_CERT_FILE=~/cacert.pem bundle install

(Reference: https://gist.github.com/fnichol/867550)

XPath contains(text(),'some string') doesn't work when used with node with more than one Text subnode

The accepted answer will return all the parent nodes too. To get only the actual nodes with ABC even if the string is after
:

//*[text()[contains(.,'ABC')]]/text()[contains(.,"ABC")]

How to install JQ on Mac by command-line?

You can install any application/packages with brew on mac. If you want to know the exact command just search your package on https://brewinstall.org and you will get the set of commands needed to install that package.

First open terminal and install brew

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)" < /dev/null 2> /dev/null

Now Install jq

brew install jq

Create Directory if it doesn't exist with Ruby

Another simple way:

Dir.mkdir('tmp/excel') unless Dir.exist?('tmp/excel')

How do I show a message in the foreach loop?

You are looking to see if a single value is in an array. Use in_array.

However note that case is important, as are any leading or trailing spaces. Use var_dump to find out the length of the strings too, and see if they fit.

How to programmatically set the SSLContext of a JAX-WS client?

I tried the following and it didn't work on my environment:

bindingProvider.getRequestContext().put("com.sun.xml.internal.ws.transport.https.client.SSLSocketFactory", getCustomSocketFactory());

But different property worked like a charm:

bindingProvider.getRequestContext().put(JAXWSProperties.SSL_SOCKET_FACTORY, getCustomSocketFactory());

The rest of the code was taken from the first reply.

Java 8: How do I work with exception throwing methods in streams?

If all you want is to invoke foo, and you prefer to propagate the exception as is (without wrapping), you can also just use Java's for loop instead (after turning the Stream into an Iterable with some trickery):

for (A a : (Iterable<A>) as::iterator) {
   a.foo();
}

This is, at least, what I do in my JUnit tests, where I don't want to go through the trouble of wrapping my checked exceptions (and in fact prefer my tests to throw the unwrapped original ones)

Fastest way to convert string to integer in PHP

I've just set up a quick benchmarking exercise:

Function             time to run 1 million iterations
--------------------------------------------
(int) "123":                0.55029
intval("123"):              1.0115  (183%)

(int) "0":                  0.42461
intval("0"):                0.95683 (225%)

(int) int:                  0.1502
intval(int):                0.65716 (438%)

(int) array("a", "b"):      0.91264
intval(array("a", "b")):    1.47681 (162%)

(int) "hello":              0.42208
intval("hello"):            0.93678 (222%)

On average, calling intval() is two and a half times slower, and the difference is the greatest if your input already is an integer.

I'd be interested to know why though.


Update: I've run the tests again, this time with coercion (0 + $var)

| INPUT ($x)      |  (int) $x  |intval($x) |  0 + $x   |
|-----------------|------------|-----------|-----------|
| "123"           |   0.51541  |  0.96924  |  0.33828  |
| "0"             |   0.42723  |  0.97418  |  0.31353  |
| 123             |   0.15011  |  0.61690  |  0.15452  |
| array("a", "b") |   0.8893   |  1.45109  |  err!     |
| "hello"         |   0.42618  |  0.88803  |  0.1691   |
|-----------------|------------|-----------|-----------|

Addendum: I've just come across a slightly unexpected behaviour which you should be aware of when choosing one of these methods:

$x = "11";
(int) $x;      // int(11)
intval($x);    // int(11)
$x + 0;        // int(11)

$x = "0x11";
(int) $x;      // int(0)
intval($x);    // int(0)
$x + 0;        // int(17) !

$x = "011";
(int) $x;      // int(11)
intval($x);    // int(11)
$x + 0;        // int(11) (not 9)

Tested using PHP 5.3.1

How to display errors for my MySQLi query?

mysqli_error()

As in:

$sql = "Your SQL statement here";
$result = mysqli_query($conn, $sql) or trigger_error("Query Failed! SQL: $sql - Error: ".mysqli_error($conn), E_USER_ERROR);

Trigger error is better than die because you can use it for development AND production, it's the permanent solution.

Adding a new value to an existing ENUM Type

When using Navicat you can go to types (under view -> others -> types) - get the design view of the type - and click the "add label" button.

Convert string with commas to array

Split it on the , character;

var string = "0,1";
var array = string.split(",");
alert(array[0]);

How to convert JSONObjects to JSONArray?

Something like this:

JSONObject songs= json.getJSONObject("songs");
Iterator x = songs.keys();
JSONArray jsonArray = new JSONArray();

while (x.hasNext()){
    String key = (String) x.next();
    jsonArray.put(songs.get(key));
}

Kill some processes by .exe file name

If you have the process ID (PID) you can kill this process as follow:

Process processToKill = Process.GetProcessById(pid);
processToKill.Kill();

Search and replace a particular string in a file using Perl

You could also do this:

#!/usr/bin/perl

use strict;
use warnings;

$^I = '.bak'; # create a backup copy 

while (<>) {
   s/<PREF>/ABCD/g; # do the replacement
   print; # print to the modified file
}

Invoke the script with by

./script.pl input_file

You will get a file named input_file, containing your changes, and a file named input_file.bak, which is simply a copy of the original file.

ESLint - "window" is not defined. How to allow global variables in package.json

I found it on this page: http://eslint.org/docs/user-guide/configuring

In package.json, this works:

"eslintConfig": {
  "globals": {
    "window": true
  }
}

How do you generate a random double uniformly distributed between 0 and 1 from C++?

Well considering simplicity and speed as your primary criteria, you can add a small generic helper like this :-

  // C++ rand generates random numbers between 0 and RAND_MAX. This is quite a big range
  // Normally one would want the generated random number within a range to be really
  // useful. So the arguments have default values which can be overridden by the caller
  int nextRandomNum(int low = 0, int high = 100) const {
    int range = (high - low) + 1;
    // this modulo operation does not generate a truly uniformly distributed random number
    // in the span (since in most cases lower numbers are slightly more likely), 
    // but it is generally a good approximation for short spans. Use it if essential
    //int res = ( std::rand() % high + low );
    int res = low + static_cast<int>( ( range * std::rand() / ( RAND_MAX + 1.0) ) );
    return res;
  }

Random number generation is a well studied, complex and advanced topic. You can find some simple but useful algorithms here apart from the ones mentioned in other answers:-

Eternally Confuzzled

How to read values from the querystring with ASP.NET Core?

ASP.NET Core will automatically bind form values, route values and query strings by name. This means you can simply do this:

[HttpGet()]
public IActionResult Get(int page)
{ ... }

MVC will try to bind request data to the action parameters by name ... below is a list of the data sources in the order that model binding looks through them

  1. Form values: These are form values that go in the HTTP request using the POST method. (including jQuery POST requests).

  2. Route values: The set of route values provided by Routing

  3. Query strings: The query string part of the URI.

Source: Model Binding in ASP.NET Core


FYI, you can also combine the automatic and explicit approaches:

[HttpGet()]
public IActionResult Get(int page
     , [FromQuery(Name = "page-size")] int pageSize)
{ ... }

sql query with multiple where statements

What is meta_key? Strip out all of the meta_value conditionals, reduce, and you end up with this:

SELECT
*
FROM
meta_data
WHERE
(
        (meta_key = 'lat')
)
AND
(
        (meta_key = 'long')
)
GROUP BY
item_id

Since meta_key can never simultaneously equal two different values, no results will be returned.


Based on comments throughout this question and answers so far, it sounds like you're looking for something more along the lines of this:

SELECT
*
FROM
meta_data
WHERE
(
    (meta_key = 'lat')
    AND
    (
        (meta_value >= '60.23457047672217')
        OR
        (meta_value <= '60.23457047672217')
    )
)
OR
(
    (meta_key = 'long')
    AND
    (
        (meta_value >= '24.879140853881836')
        OR
        (meta_value <= '24.879140853881836')
    )
)
GROUP BY
item_id

Note the OR between the top-level conditionals. This is because you want records which are lat or long, since no single record will ever be lat and long.

I'm still not sure what you're trying to accomplish by the inner conditionals. Any non-null value will match those numbers. So maybe you can elaborate on what you're trying to do there. I'm also not sure about the purpose of the GROUP BY clause, but that might be outside the context of this question entirely.

How to get all count of mongoose model?

The collection.count is deprecated, and will be removed in a future version. Use collection.countDocuments or collection.estimatedDocumentCount instead.

userModel.countDocuments(query).exec((err, count) => {
    if (err) {
        res.send(err);
        return;
    }

    res.json({ count: count });
});

Difference between e.target and e.currentTarget

e.currentTarget is always the element the event is actually bound do. e.target is the element the event originated from, so e.target could be a child of e.currentTarget, or e.target could be === e.currentTarget, depending on how your markup is structured.

MySQL order by before group by

Using an ORDER BY in a subquery is not the best solution to this problem.

The best solution to get the max(post_date) by author is to use a subquery to return the max date and then join that to your table on both the post_author and the max date.

The solution should be:

SELECT p1.* 
FROM wp_posts p1
INNER JOIN
(
    SELECT max(post_date) MaxPostDate, post_author
    FROM wp_posts
    WHERE post_status='publish'
       AND post_type='post'
    GROUP BY post_author
) p2
  ON p1.post_author = p2.post_author
  AND p1.post_date = p2.MaxPostDate
WHERE p1.post_status='publish'
  AND p1.post_type='post'
order by p1.post_date desc

If you have the following sample data:

CREATE TABLE wp_posts
    (`id` int, `title` varchar(6), `post_date` datetime, `post_author` varchar(3))
;

INSERT INTO wp_posts
    (`id`, `title`, `post_date`, `post_author`)
VALUES
    (1, 'Title1', '2013-01-01 00:00:00', 'Jim'),
    (2, 'Title2', '2013-02-01 00:00:00', 'Jim')
;

The subquery is going to return the max date and author of:

MaxPostDate | Author
2/1/2013    | Jim

Then since you are joining that back to the table, on both values you will return the full details of that post.

See SQL Fiddle with Demo.

To expand on my comments about using a subquery to accurate return this data.

MySQL does not force you to GROUP BY every column that you include in the SELECT list. As a result, if you only GROUP BY one column but return 10 columns in total, there is no guarantee that the other column values which belong to the post_author that is returned. If the column is not in a GROUP BY MySQL chooses what value should be returned.

Using the subquery with the aggregate function will guarantee that the correct author and post is returned every time.

As a side note, while MySQL allows you to use an ORDER BY in a subquery and allows you to apply a GROUP BY to not every column in the SELECT list this behavior is not allowed in other databases including SQL Server.

Removing all non-numeric characters from string in Python

Just to add another option to the mix, there are several useful constants within the string module. While more useful in other cases, they can be used here.

>>> from string import digits
>>> ''.join(c for c in "abc123def456" if c in digits)
'123456'

There are several constants in the module, including:

  • ascii_letters (abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ)
  • hexdigits (0123456789abcdefABCDEF)

If you are using these constants heavily, it can be worthwhile to covert them to a frozenset. That enables O(1) lookups, rather than O(n), where n is the length of the constant for the original strings.

>>> digits = frozenset(digits)
>>> ''.join(c for c in "abc123def456" if c in digits)
'123456'

static and extern global variables in C and C++

When you #include a header, it's exactly as if you put the code into the source file itself. In both cases the varGlobal variable is defined in the source so it will work no matter how it's declared.

Also as pointed out in the comments, C++ variables at file scope are not static in scope even though they will be assigned to static storage. If the variable were a class member for example, it would need to be accessible to other compilation units in the program by default and non-class members are no different.

JQuery post JSON object to a server

To send json to the server, you first have to create json

function sendData() {
    $.ajax({
        url: '/helloworld',
        type: 'POST',
        contentType: 'application/json',
        data: JSON.stringify({
            name:"Bob",
            ...
        }),
        dataType: 'json'
    });
}

This is how you would structure the ajax request to send the json as a post var.

function sendData() {
    $.ajax({
        url: '/helloworld',
        type: 'POST',
        data: { json: JSON.stringify({
            name:"Bob",
            ...
        })},
        dataType: 'json'
    });
}

The json will now be in the json post var.

Set color of text in a Textbox/Label to Red and make it bold in asp.net C#

Try using the property ForeColor. Like this :

TextBox1.ForeColor = Color.Red;

Connect HTML page with SQL server using javascript

Before The execution of following code, I assume you have created a database and a table (with columns Name (varchar), Age(INT) and Address(varchar)) inside that database. Also please update your SQL Server name , UserID, password, DBname and table name in the code below.

In the code. I have used VBScript and embedded it in HTML. Try it out!

<!DOCTYPE html>
<html>
<head>
<script type="text/vbscript">
<!--    

Sub Submit_onclick()
Dim Connection
Dim ConnString
Dim Recordset

Set connection=CreateObject("ADODB.Connection")
Set Recordset=CreateObject("ADODB.Recordset")
ConnString="DRIVER={SQL Server};SERVER=*YourSQLserverNameHere*;UID=*YourUserIdHere*;PWD=*YourpasswordHere*;DATABASE=*YourDBNameHere*"
Connection.Open ConnString

dim form1
Set form1 = document.Register

Name1 = form1.Name.value
Age1 = form1.Age.Value
Add1 = form1.address.value

connection.execute("INSERT INTO [*YourTableName*] VALUES ('"&Name1 &"'," &Age1 &",'"&Add1 &"')")

End Sub

//-->
</script>
</head>
<body>

<h2>Please Fill details</h2><br>
<p>
<form name="Register">
<pre>
<font face="Times New Roman" size="3">Please enter the log in credentials:<br>
Name:   <input type="text" name="Name">
Age:        <input type="text" name="Age">
Address:        <input type="text" name="address">
<input type="button" id ="Submit" value="submit" /><font></form> 
</p>
</pre>
</body>
</html>

How do I get specific properties with Get-AdUser

using select-object for example:

Get-ADUser -Filter * -SearchBase 'OU=Users & Computers, DC=aaaaaaa, DC=com' -Properties DisplayName | select -expand displayname | Export-CSV "ADUsers.csv" 

PHP UML Generator

Have you tried Autodia yet? Last time I tried it it wasn't perfect, but it was good enough.

Gradle - Could not find or load main class

I see two problems here, one with sourceSet another with mainClassName.

  1. Either move java source files to src/main/java instead of just src. Or set sourceSet properly by adding the following to build.gradle.

    sourceSets.main.java.srcDirs = ['src']
    
  2. mainClassName should be fully qualified class name, not path.

    mainClassName = "hello.HelloWorld"
    

phpinfo() is not working on my CentOS server

Try to create a php.ini file in root and write the following command in and save it.

disable_functions =

Using this code will enable the phpinfo() function for you if it is disabled by the global PHP configuration.

Error 330 (net::ERR_CONTENT_DECODING_FAILED):

We also had this problem when upgrading our system to Revive. After turning of GZIP we found the problem still persisted. Upon further investigation we found the file permissions where not correct after the upgrade. A simple recursive chmod did the trick.

How to type ":" ("colon") in regexp?

Be careful, - has a special meaning with regexp. In a [], you can put it without problem if it is placed at the end. In your case, ,-: is taken as from , to :.

MySQL/SQL: Group by date only on a Datetime column

Cast the datetime to a date, then GROUP BY using this syntax:

SELECT SUM(foo), DATE(mydate) FROM a_table GROUP BY DATE(a_table.mydate);

Or you can GROUP BY the alias as @orlandu63 suggested:

SELECT SUM(foo), DATE(mydate) DateOnly FROM a_table GROUP BY DateOnly;

Though I don't think it'll make any difference to performance, it is a little clearer.

How to solve munmap_chunk(): invalid pointer error in C++

The hint is, the output file is created even if you get this error. The automatic deconstruction of vector starts after your code executed. Elements in the vector are deconstructed as well. This is most probably where the error occurs. The way you access the vector is through vector::operator[] with an index read from stream. Try vector::at() instead of vector::operator[]. This won't solve your problem, but will show which assignment to the vector causes error.

A CORS POST request works from plain JavaScript, but why not with jQuery?

Another possibility is that setting dataType: json causes JQuery to send the Content-Type: application/json header. This is considered a non-standard header by CORS, and requires a CORS preflight request. So a few things to try:

1) Try configuring your server to send the proper preflight responses. This will be in the form of additional headers like Access-Control-Allow-Methods and Access-Control-Allow-Headers.

2) Drop the dataType: json setting. JQuery should request Content-Type: application/x-www-form-urlencoded by default, but just to be sure, you can replace dataType: json with contentType: 'application/x-www-form-urlencoded'

How can I list the scheduled jobs running in my database?

I think you need the SCHEDULER_ADMIN role to see the dba_scheduler tables (however this may grant you too may rights)

see: http://download.oracle.com/docs/cd/B28359_01/server.111/b28310/schedadmin001.htm

"npm config set registry https://registry.npmjs.org/" is not working in windows bat file

You might not be able to change npm registry using .bat file as Gntem pointed out. But I understand that you need the ability to automate changing registries. You can do so by having your .npmrc configs in separate files (say npmrc_jfrog & npmrc_default) and have your .bat files do the copying task.

For example (in Windows): Your default_registry.bat will have

xcopy /y npmrc_default .npmrc

and your jfrog_registry.bat will have

xcopy /y npmrc_jfrog .npmrc

Note: /y suppresses prompting to confirm that you want to overwrite an existing destination file.

This will make sure that all the config properties (registry, proxy, apiKeys, etc.) get copied over to .npmrc.

You can read more about xcopy here.

How to disable or enable viewpager swiping in android

Disable swipe progmatically by-

    final View touchView = findViewById(R.id.Pager); 
    touchView.setOnTouchListener(new View.OnTouchListener() 
    {         
        @Override
        public boolean onTouch(View v, MotionEvent event)
        { 
           return true; 
        }
     });

and use this to swipe manually

touchView.setCurrentItem(int index);

(SC) DeleteService FAILED 1072

In Windows 7, make sure Event Viewer closed before deleting.

Including jars in classpath on commandline (javac or apt)

Try the following:

java -cp jar1:jar2:jar3:dir1:. HelloWorld

The default classpath (unless there is a CLASSPATH environment variable) is the current directory so if you redefine it, make sure you're adding the current directory (.) to the classpath as I have done.

JavaScript split String with white space

For split string by space like in Python lang, can be used:

   var w = "hello    my brothers    ;";
   w.split(/(\s+)/).filter( function(e) { return e.trim().length > 0; } );

output:

   ["hello", "my", "brothers", ";"]

or similar:

   w.split(/(\s+)/).filter( e => e.trim().length > 0)

(output some)

Unzip files (7-zip) via cmd command

In Windows 10 I had to run the batch file as an administrator.

Convert UNIX epoch to Date object

With library(lubridate), numeric representations of date and time saved as the number of seconds since 1970-01-01 00:00:00 UTC, can be coerced into dates with as_datetime():

lubridate::as_datetime(1352068320)

[1] "2012-11-04 22:32:00 UTC"

How do I delete NuGet packages that are not referenced by any project in my solution?

If you have removed package using Uninstall-Package utility and deleted the desired package from package directory under solution (and you are still getting error), just open up the *.csproj file in code editor and remove the tag manually. Like for instance, I wanted to get rid of Nuget package Xamarin.Forms.Alias and I removed these lines from *.csproj file.

Removing nuget package from msbuild script

And finally, don't forget to reload your project once prompted in Visual Studio (after changing project file). I tried it on Visual Studio 2015, but it should work on Visual Studio 2010 and onward too.

Hope this helps.

downcast and upcast

Answer 1 : Yes it called upcasting but the way you do it is not modern way. Upcasting can be performed implicitly you don't need any conversion. So just writing Employee emp = mgr; is enough for upcasting.

Answer 2 : If you create object of Manager class we can say that manager is an employee. Because class Manager : Employee depicts Is-A relationship between Employee Class and Manager Class. So we can say that every manager is an employee.

But if we create object of Employee class we can not say that this employee is manager because class Employee is a class which is not inheriting any other class. So you can not directly downcast that Employee Class object to Manager Class object.

So answer is, if you want to downcast from Employee Class object to Manager Class object, first you must have object of Manager Class first then you can upcast it and then you can downcast it.

Get gateway ip address in android

DNS server is obtained via

getprop net.dns1 

UPDATE: as of Android Nougat 7.x, ifconfig is present, and netcfg is gone. So ifconfig can be used to find the IP and netmask.

How can I debug git/git-shell related problems?

try this one:

GIT_TRACE=1 git pull origin master

Display all views on oracle database

SELECT * 
FROM DBA_OBJECTS  
WHERE OBJECT_TYPE = 'VIEW'

Java: Instanceof and Generics

The runtime type of the object is a relatively arbitrary condition to filter on. I suggest keeping such muckiness away from your collection. This is simply achieved by having your collection delegate to a filter passed in a construction.

public interface FilterObject {
     boolean isAllowed(Object obj);
}

public class FilterOptimizedList<E> implements List<E> {
     private final FilterObject filter;
     ...
     public FilterOptimizedList(FilterObject filter) {
         if (filter == null) {
             throw NullPointerException();
         }
         this.filter = filter;
     }
     ...
     public int indexOf(Object obj) {
         if (!filter.isAllows(obj)) {
              return -1;
         }
         ...
     }
     ...
}

     final List<String> longStrs = new FilterOptimizedList<String>(
         new FilterObject() { public boolean isAllowed(Object obj) {
             if (obj == null) {
                 return true;
             } else if (obj instanceof String) {
                 String str = (String)str;
                 return str.length() > = 4;
             } else {
                 return false;
             }
         }}
     );

log4net vs. Nlog

If you go here you can find a comprehensive matrix that includes both the NLog and Log4Net libs as well as Enterprise Lib and other products.

Somebody could argue that the matrix is done in a way to underline the features of the only commercial lib present in the matrix. I think it's true but it was useful anyway to drive my choice versus NLog.

Regards

How do you test that a Python function throws an exception?

The code in my previous answer can be simplified to:

def test_afunction_throws_exception(self):
    self.assertRaises(ExpectedException, afunction)

And if afunction takes arguments, just pass them into assertRaises like this:

def test_afunction_throws_exception(self):
    self.assertRaises(ExpectedException, afunction, arg1, arg2)

prevent refresh of page when button inside form clicked

All you need to do is put a type tag and make the type button.

_x000D_
_x000D_
<button id="btnId" type="button">Hide/Show</button>
_x000D_
_x000D_
_x000D_

That solves the issue

eslint: error Parsing error: The keyword 'const' is reserved

ESLint defaults to ES5 syntax-checking. You'll want to override to the latest well-supported version of JavaScript.

Try adding a .eslintrc file to your project. Inside it:

{
    "parserOptions": {
        "ecmaVersion": 2017
    },

    "env": {
        "es6": true
    }
}

Hopefully this helps.

EDIT: I also found this example .eslintrc which might help.

Java List.contains(Object with field value equal to x)

contains method uses equals internally. So you need to override the equals method for your class as per your need.

Btw this does not look syntatically correct:

new Object().setName("John")

Iterating over Numpy matrix rows to apply a function each?

While you should certainly provide more information, if you are trying to go through each row, you can just iterate with a for loop:

import numpy
m = numpy.ones((3,5),dtype='int')
for row in m:
  print str(row)

laravel compact() and ->with()

the best way for me :

    $data=[
'var1'=>'something',
'var2'=>'something',
'var3'=>'something',
      ];
return View::make('view',$data);

Format Date as "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'"

Add another option, maybe not the most lightweight.

_x000D_
_x000D_
dayjs.extend(dayjs_plugin_customParseFormat)
console.log(dayjs('2018-09-06 17:00:00').format( 'YYYY-MM-DDTHH:mm:ss.000ZZ'))
_x000D_
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dayjs.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/[email protected]/plugin/customParseFormat.js"></script>
_x000D_
_x000D_
_x000D_

How to style SVG <g> element?

You actually cannot draw Container Elements

But you can use a "foreignObject" with a "SVG" inside it to simulate what you need.

http://jsfiddle.net/VBmbP/4/

<svg width="640" height="480" xmlns="http://www.w3.org/2000/svg">
      <foreignObject id="G" width="300" height="200">
        <svg>
          <rect fill="blue" stroke-width="2" height="112" width="84" y="55" x="55" stroke-linecap="null" stroke-linejoin="null" stroke-dasharray="null" stroke="#000000"/>
          <ellipse fill="#FF0000" stroke="#000000" stroke-width="5" stroke-dasharray="null" stroke-linejoin="null" stroke-linecap="null" cx="155" cy="65" id="svg_7" rx="64" ry="56"/>     
        </svg>
          <style>
              #G {
                background: #cff; border: 1px dashed black;
              }
              #G:hover {
                background: #acc; border: 1px solid black;
              }
          </style>
      </foreignObject>
    </svg>

In Android EditText, how to force writing uppercase?

For me it worked by adding android:textAllCaps="true" and android:inputType="textCapCharacters"

<android.support.design.widget.TextInputEditText
                    android:layout_width="fill_parent"
                    android:layout_height="@dimen/edit_text_height"
                    android:textAllCaps="true"
                    android:inputType="textCapCharacters"
                    />

Convert a string representation of a hex dump to a byte array using Java?

Based on the op voted solution, the following should be a bit more efficient:

  public static byte [] hexStringToByteArray (final String s) {
    if (s == null || (s.length () % 2) == 1)
      throw new IllegalArgumentException ();
    final char [] chars = s.toCharArray ();
    final int len = chars.length;
    final byte [] data = new byte [len / 2];
    for (int i = 0; i < len; i += 2) {
      data[i / 2] = (byte) ((Character.digit (chars[i], 16) << 4) + Character.digit (chars[i + 1], 16));
    }
    return data;
  }

Because: the initial conversion to a char array spares the length checks in charAt

add scroll bar to table body

you can wrap the content of the <tbody> in a scrollable <div> :

html

....
<tbody>
  <tr>
    <td colspan="2">
      <div class="scrollit">
        <table>
          <tr>
            <td>January</td>
            <td>$100</td>
          </tr>
          <tr>
            <td>February</td>
            <td>$80</td>
          </tr>
          <tr>
            <td>January</td>
            <td>$100</td>
          </tr>
          <tr>
            <td>February</td>
            <td>$80</td>
          </tr>
          ...

css

.scrollit {
    overflow:scroll;
    height:100px;
}

see my jsfiddle, forked from yours: http://jsfiddle.net/VTNax/2/

Recommended website resolution (width and height)?

I target the 1024 pixel monitors (but don't use 100% of that space). I've given up on those with 800x600. I'd rather punish the few with outdated hardware by making them scroll if they need to, versus punishing everyone with new equipment by wasting space.

I suppose it depends on your audience, and the nature of you app though.

What is the difference between =Empty and IsEmpty() in VBA (Excel)?

I believe IsEmpty is just method that takes return value of Cell and checks if its Empty so: IsEmpty(.Cell(i,1)) does ->

return .Cell(i,1) <> Empty

How to change colors of a Drawable in Android?

It's very very simple when you use a library to do that for you. Try this library

You can call like this:

Icon.on(holderView).color(R.color.your_color).icon(R.mipmap.your_icon).put();

Extension methods must be defined in a non-generic static class

Change it to

public static class LinqHelper

how to configure hibernate config file for sql server

Properties that are database specific are:

  • hibernate.connection.driver_class: JDBC driver class
  • hibernate.connection.url: JDBC URL
  • hibernate.connection.username: database user
  • hibernate.connection.password: database password
  • hibernate.dialect: The class name of a Hibernate org.hibernate.dialect.Dialect which allows Hibernate to generate SQL optimized for a particular relational database.

To change the database, you must:

  1. Provide an appropriate JDBC driver for the database on the class path,
  2. Change the JDBC properties (driver, url, user, password)
  3. Change the Dialect used by Hibernate to talk to the database

There are two drivers to connect to SQL Server; the open source jTDS and the Microsoft one. The driver class and the JDBC URL depend on which one you use.

With the jTDS driver

The driver class name is net.sourceforge.jtds.jdbc.Driver.

The URL format for sqlserver is:

 jdbc:jtds:sqlserver://<server>[:<port>][/<database>][;<property>=<value>[;...]]

So the Hibernate configuration would look like (note that you can skip the hibernate. prefix in the properties):

<hibernate-configuration>
  <session-factory>
    <property name="connection.driver_class">net.sourceforge.jtds.jdbc.Driver</property>
    <property name="connection.url">jdbc:jtds:sqlserver://<server>[:<port>][/<database>]</property>
    <property name="connection.username">sa</property>
    <property name="connection.password">lal</property>

    <property name="dialect">org.hibernate.dialect.SQLServerDialect</property>

    ...
  </session-factory>
</hibernate-configuration>

With Microsoft SQL Server JDBC 3.0:

The driver class name is com.microsoft.sqlserver.jdbc.SQLServerDriver.

The URL format is:

jdbc:sqlserver://[serverName[\instanceName][:portNumber]][;property=value[;property=value]]

So the Hibernate configuration would look like:

<hibernate-configuration>
  <session-factory>
    <property name="connection.driver_class">com.microsoft.sqlserver.jdbc.SQLServerDriver</property>
    <property name="connection.url">jdbc:sqlserver://[serverName[\instanceName][:portNumber]];databaseName=<databaseName></property>
    <property name="connection.username">sa</property>
    <property name="connection.password">lal</property>

    <property name="dialect">org.hibernate.dialect.SQLServerDialect</property>

    ...
  </session-factory>
</hibernate-configuration>

References

PHP Warning Permission denied (13) on session_start()

do a phpinfo(), and look for session.save_path. the directory there needs to have the correct permissions for the user and/or group that your webserver runs as

How to send a POST request using volley with string body?

I created a function for a Volley Request. You just need to pass the arguments :

public void callvolly(final String username, final String password){
    RequestQueue MyRequestQueue = Volley.newRequestQueue(this);
    String url = "http://your_url.com/abc.php"; // <----enter your post url here
    StringRequest MyStringRequest = new StringRequest(Request.Method.POST, url, new Response.Listener<String>() {
        @Override
        public void onResponse(String response) {
            //This code is executed if the server responds, whether or not the response contains data.
            //The String 'response' contains the server's response.
        }
    }, new Response.ErrorListener() { //Create an error listener to handle errors appropriately.
        @Override
        public void onErrorResponse(VolleyError error) {
            //This code is executed if there is an error.
        }
    }) {
        protected Map<String, String> getParams() {
            Map<String, String> MyData = new HashMap<String, String>();
            MyData.put("username", username);             
            MyData.put("password", password);                
            return MyData;
        }
    };


    MyRequestQueue.add(MyStringRequest);
}

Working with $scope.$emit and $scope.$on

To send $scope object from one controller to another, I will discuss about $rootScope.$broadcast and $rootScope.$emit here as they are used most.

Case 1:

$rootScope.$broadcast:-

$rootScope.$broadcast('myEvent',$scope.data);//Here `myEvent` is event name

$rootScope.$on('myEvent', function(event, data) {} //listener on `myEvent` event

$rootScope listener are not destroyed automatically. You need to destroy it using $destroy. It is better to use $scope.$on as listeners on $scope are destroyed automatically i.e. as soon as $scope is destroyed.

$scope.$on('myEvent', function(event, data) {}

Or,

  var customeEventListener = $rootScope.$on('myEvent', function(event, data) {

  }
  $scope.$on('$destroy', function() {
        customeEventListener();
  });

Case 2:

$rootScope.$emit:

   $rootScope.$emit('myEvent',$scope.data);

   $rootScope.$on('myEvent', function(event, data) {}//$scope.$on not works

The major difference in $emit and $broadcast is that $rootScope.$emit event must be listened using $rootScope.$on, because the emitted event never comes down through the scope tree..
In this case also you must destroy the listener as in the case of $broadcast.

Edit:

I prefer not to use $rootScope.$broadcast + $scope.$on but use $rootScope.$emit+ $rootScope.$on. The $rootScope.$broadcast + $scope.$on combo can cause serious performance problems. That is because the event will bubble down through all scopes.

Edit 2:

The issue addressed in this answer have been resolved in angular.js version 1.2.7. $broadcast now avoids bubbling over unregistered scopes and runs just as fast as $emit.

Override hosts variable of Ansible playbook from the command line

This is a bit late, but I think you could use the --limit or -l command to limit the pattern to more specific hosts. (version 2.3.2.0)

You could have - hosts: all (or group) tasks: - some_task

and then ansible-playbook playbook.yml -l some_more_strict_host_or_pattern and use the --list-hosts flag to see on which hosts this configuration would be applied.

How to get Android GPS location

The initial issue is solved by changing lat and lon to double.

I want to add comment to solution with Location location = locationManager.getLastKnownLocation(bestProvider); It works to find out last known location when other app was lisnerning for that. If, for example, no app did that since device start, the code will return zeros (spent some time myself recently to figure that out).

Also, it's a good practice to stop listening when there is no need for that by locationManager.removeUpdates(this);

Also, even with permissions in manifest, the code works when location service is enabled in Android settings on a device.

SSL peer shut down incorrectly in Java

I was having the same issue, as everyone else I suppose.. adding the System.setProperties(....) didn't fix it for me.

So my email client is in a separate project uploaded to an artifactory. I'm importing this project into other projects as a gradle dependency. My problem was that I was using implementation in my build.gradle for javax.mail, which was causing issues downstream.
I changed this line from implementation to api and my downstream project started working and connecting again.

convert a list of objects from one type to another using lambda expression

Here's a simple example..

List<char> c = new List<char>() { 'A', 'B', 'C' };

List<string> s = c.Select(x => x.ToString()).ToList();

Convert DOS line endings to Linux line endings in Vim

I typically use

:%s/\r/\r/g

which seems a little odd, but works because of the way that Vim matches linefeeds. I also find it easier to remember :)

How to access static resources when mapping a global front controller servlet on /*

The reason for the collision seems to be because, by default, the context root, "/", is to be handled by org.apache.catalina.servlets.DefaultServlet. This servlet is intended to handle requests for static resources.

If you decide to bump it out of the way with your own servlet, with the intent of handling dynamic requests, that top-level servlet must also carry out any tasks accomplished by catalina's original "DefaultServlet" handler.

If you read through the tomcat docs, they make mention that True Apache (httpd) is better than Apache Tomcat for handling static content, since it is purpose built to do just that. My guess is because Tomcat by default uses org.apache.catalina.servlets.DefaultServlet to handle static requests. Since it's all wrapped up in a JVM, and Tomcat is intended to as a Servlet/JSP container, they probably didn't write that class as a super-optimized static content handler. It's there. It gets the job done. Good enough.

But that's the thing that handles static content and it lives at "/". So if you put anything else there, and that thing doesn't handle static requests, WHOOPS, there goes your static resources.

I've been searching high and low for the same answer and the answer I'm getting everywhere is "if you don't want it to do that, don't do that".

So long story short, your configuration is displacing the default static resource handler with something that isn't a static resource handler at all. You'll need to try a different configuration to get the results you're looking for (as will I).

Advantages of SQL Server 2008 over SQL Server 2005?

SQL 2008 also allows you to disable lock escalation on specific tables. I have found this very useful on small frequently updated tables where locks can escalate causing concurrency issues. In SQL 2005, even with the ROWLOCK hint on delete statements locks can be escalated which can lead to deadlocks. In my testing, an application which I have developed had concurrency issues during small table manipulation due to lock escalation on SQL 2005. In SQL 2008 this problem went away.

It is still important to bear in mind the potential overhead of handling large numbers of row locks, but having the option to stop escalation when you want to is very useful.

How do I pass multiple ints into a vector at once?

using vector::insert (const_iterator position, initializer_list il); http://www.cplusplus.com/reference/vector/vector/insert/

#include <iostream>
#include <vector>

int main() {
  std::vector<int> vec;
  vec.insert(vec.end(),{1,2,3,4});
  return 0;
}

how to add value to combobox item

If you want to use SelectedValue then your combobox must be databound.

To set up the combobox:

ComboBox1.DataSource = GetMailItems()
ComboBox1.DisplayMember = "Name"
ComboBox1.ValueMember = "ID"

To get the data:

Function GetMailItems() As List(Of MailItem)

    Dim mailItems = New List(Of MailItem)

    Command = New MySqlCommand("SELECT * FROM `maillist` WHERE l_id = '" & id & "'", connection)
    Command.CommandTimeout = 30
    Reader = Command.ExecuteReader()

    If Reader.HasRows = True Then
        While Reader.Read()
            mailItems.Add(New MailItem(Reader("ID"), Reader("name")))
        End While
    End If

    Return mailItems

End Function

Public Class MailItem

    Public Sub New(ByVal id As Integer, ByVal name As String)
        mID = id
        mName = name
    End Sub

    Private mID As Integer
    Public Property ID() As Integer
        Get
            Return mID
        End Get
        Set(ByVal value As Integer)
            mID = value
        End Set
    End Property

    Private mName As String
    Public Property Name() As String
        Get
            Return mName
        End Get
        Set(ByVal value As String)
            mName = value
        End Set
    End Property

End Class

How can I jump to class/method definition in Atom text editor?

For Typescript users, the "atom-typescript" package adds a typescript aware symbols view, you can trigger it with Cmd+R, and it works great to jump to methods-

https://atom.io/packages/atom-typescript#alternative-to-symbols-view

XmlSerializer giving FileNotFoundException at constructor

I ran into this exact issue and couldn't get around it by any of the solutions mentioned.

Then I finally found a solution. It appears that the serializer needs not only the type, but the nested types as well. Changing this:

XmlSerializer xmlSerializer = new XmlSerializer(typeof(T));

To this:

XmlSerializer xmlSerializer = new XmlSerializer(typeof(T).GetNestedTypes());

Fixed the issue for me. No more exceptions or anything.

ASP.NET 4.5 has not been registered on the Web server

For Windows 8 client computers, turn on "IIS-ASPNET45" in "Turn Windows Features On/Off" under "Internet Information Services-> World Wide Web Services -> Application Development Features -> ASP.NET 4.5".

Convert string in base64 to image and save on filesystem in Python

If the imagestr was bitmap data (which we now know it isn't) you could use this

imagestr is the base64 encoded string
width is the width of the image
height is the height of the image

from PIL import Image
from base64 import decodestring

image = Image.fromstring('RGB',(width,height),decodestring(imagestr))
image.save("foo.png")

Since the imagestr is just the encoded png data

from base64 import decodestring

with open("foo.png","wb") as f:
    f.write(decodestring(imagestr))

Likelihood of collision using most significant bits of a UUID in Java

You are better off just generating a random long value, then all the bits are random. In Java 6, new Random() uses the System.nanoTime() plus a counter as a seed.

There are different levels of uniqueness.

If you need uniqueness across many machines, you could have a central database table for allocating unique ids, or even batches of unique ids.

If you just need to have uniqueness in one app you can just have a counter (or a counter which starts from the currentTimeMillis()*1000 or nanoTime() depending on your requirements)

path.join vs path.resolve with __dirname

const absolutePath = path.join(__dirname, some, dir);

vs.

const absolutePath = path.resolve(__dirname, some, dir);

path.join will concatenate __dirname which is the directory name of the current file concatenated with values of some and dir with platform-specific separator.

Whereas

path.resolve will process __dirname, some and dir i.e. from right to left prepending it by processing it.

If any of the values of some or dir corresponds to a root path then the previous path will be omitted and process rest by considering it as root

In order to better understand the concept let me explain both a little bit more detail as follows:-

The path.join and path.resolve are two different methods or functions of the path module provided by nodejs.

Where both accept a list of paths but the difference comes in the result i.e. how they process these paths.

path.join concatenates all given path segments together using the platform-specific separator as a delimiter, then normalizes the resulting path. While the path.resolve() process the sequence of paths from right to left, with each subsequent path prepended until an absolute path is constructed.

When no arguments supplied

The following example will help you to clearly understand both concepts:-

My filename is index.js and the current working directory is E:\MyFolder\Pjtz\node

const path = require('path');

console.log("path.join() : ", path.join());
// outputs .
console.log("path.resolve() : ", path.resolve());
// outputs current directory or equivalent to __dirname

Result

? node index.js
path.join() :  .
path.resolve() :  E:\MyFolder\Pjtz\node

path.resolve() method will output the absolute path whereas the path.join() returns . representing the current working directory if nothing is provided

When some root path is passed as arguments

const path=require('path');

console.log("path.join() : " ,path.join('abc','/bcd'));
console.log("path.resolve() : ",path.resolve('abc','/bcd'));

Result i

? node index.js
path.join() :  abc\bcd
path.resolve() :  E:\bcd

path.join() only concatenates the input list with platform-specific separator while the path.resolve() process the sequence of paths from right to left, with each subsequent path prepended until an absolute path is constructed.

Kill a postgresql session/connection

For me worked the following:

sudo gitlab-ctl stop
sudo gitlab-ctl start gitaly
sudo gitlab-rake gitlab:setup [type yes and let it finish]
sudo gitlab-ctl start

I am using:
gitlab_edition: "gitlab-ce"
gitlab_version: '12.4.0-ce.0.el7'

Angular2 change detection: ngOnChanges not firing for nested object

My 'hack' solution is

   <div class="col-sm-5">
        <laps
            [lapsData]="rawLapsData"
            [selectedTps]="selectedTps"
            (lapsHandler)="lapsHandler($event)">
        </laps>
    </div>
    <map
        [lapsData]="rawLapsData"
        [selectedTps]="selectedTps"   // <--------
        class="col-sm-7">
    </map>

selectedTps changes at the same time as rawLapsData and that gives map another chance to detect the change through a simpler object primitive type. It is NOT elegant, but it works.

Prevent Android activity dialog from closing on outside touch

Here is my solution:

AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Select The Difficulty Level");
builder.setCancelable(false);

Thread pooling in C++11

This is another thread pool implementation that is very simple, easy to understand and use, uses only C++11 standard library, and can be looked at or modified for your uses, should be a nice starter if you want to get into using thread pools:

https://github.com/progschj/ThreadPool

How do I check for equality using Spark Dataframe without SQL Query?

To get the negation, do this ...

df.filter(not( ..expression.. ))

eg

df.filter(not($"state" === "TX"))

Java inner class and static nested class

I don't think the real difference became clear in the above answers.

First to get the terms right:

  • A nested class is a class which is contained in another class at the source code level.
  • It is static if you declare it with the static modifier.
  • A non-static nested class is called inner class. (I stay with non-static nested class.)

Martin's answer is right so far. However, the actual question is: What is the purpose of declaring a nested class static or not?

You use static nested classes if you just want to keep your classes together if they belong topically together or if the nested class is exclusively used in the enclosing class. There is no semantic difference between a static nested class and every other class.

Non-static nested classes are a different beast. Similar to anonymous inner classes, such nested classes are actually closures. That means they capture their surrounding scope and their enclosing instance and make that accessible. Perhaps an example will clarify that. See this stub of a Container:

public class Container {
    public class Item{
        Object data;
        public Container getContainer(){
            return Container.this;
        }
        public Item(Object data) {
            super();
            this.data = data;
        }

    }

    public static Item create(Object data){
        // does not compile since no instance of Container is available
        return new Item(data);
    }
    public Item createSubItem(Object data){
        // compiles, since 'this' Container is available
        return new Item(data);
    }
}

In this case you want to have a reference from a child item to the parent container. Using a non-static nested class, this works without some work. You can access the enclosing instance of Container with the syntax Container.this.

More hardcore explanations following:

If you look at the Java bytecodes the compiler generates for an (non-static) nested class it might become even clearer:

// class version 49.0 (49)
// access flags 33
public class Container$Item {

  // compiled from: Container.java
  // access flags 1
  public INNERCLASS Container$Item Container Item

  // access flags 0
  Object data

  // access flags 4112
  final Container this$0

  // access flags 1
  public getContainer() : Container
   L0
    LINENUMBER 7 L0
    ALOAD 0: this
    GETFIELD Container$Item.this$0 : Container
    ARETURN
   L1
    LOCALVARIABLE this Container$Item L0 L1 0
    MAXSTACK = 1
    MAXLOCALS = 1

  // access flags 1
  public <init>(Container,Object) : void
   L0
    LINENUMBER 12 L0
    ALOAD 0: this
    ALOAD 1
    PUTFIELD Container$Item.this$0 : Container
   L1
    LINENUMBER 10 L1
    ALOAD 0: this
    INVOKESPECIAL Object.<init>() : void
   L2
    LINENUMBER 11 L2
    ALOAD 0: this
    ALOAD 2: data
    PUTFIELD Container$Item.data : Object
    RETURN
   L3
    LOCALVARIABLE this Container$Item L0 L3 0
    LOCALVARIABLE data Object L0 L3 2
    MAXSTACK = 2
    MAXLOCALS = 3
}

As you can see the compiler creates a hidden field Container this$0. This is set in the constructor which has an additional parameter of type Container to specify the enclosing instance. You can't see this parameter in the source but the compiler implicitly generates it for a nested class.

Martin's example

OuterClass.InnerClass innerObject = outerObject.new InnerClass();

would so be compiled to a call of something like (in bytecodes)

new InnerClass(outerObject)

For the sake of completeness:

An anonymous class is a perfect example of a non-static nested class which just has no name associated with it and can't be referenced later.

Node.js heap out of memory

I've faced this same problem recently and came across to this thread but my problem was with React App. Below changes in the node start command solved my issues.

Syntax

node --max-old-space-size=<size> path-to/fileName.js

Example

node --max-old-space-size=16000 scripts/build.js

Why size is 16000 in max-old-space-size?

Basically, it varies depends on the allocated memory to that thread and your node settings.

How to verify and give right size?

This is basically stay in our engine v8. below code helps you to understand the Heap Size of your local node v8 engine.

const v8 = require('v8');
const totalHeapSize = v8.getHeapStatistics().total_available_size;
const totalHeapSizeGb = (totalHeapSize / 1024 / 1024 / 1024).toFixed(2);
console.log('totalHeapSizeGb: ', totalHeapSizeGb);

How to add new elements to an array?

It's also possible to pre-allocate large enough memory size. Here is a simple stack implementation: the program is supposed to output 3 and 5.

class Stk {
    static public final int STKSIZ = 256;
    public int[] info = new int[STKSIZ];
    public int sp = 0; // stack pointer
    public void push(int value) {
        info[sp++] = value;
    }
}
class App {
    public static void main(String[] args) {
        Stk stk = new Stk();
        stk.push(3);
        stk.push(5);
        System.out.println(stk.info[0]);
        System.out.println(stk.info[1]);
    }
}

Fit cell width to content

For me, this is the best autofit and autoresize for table and its columns (use css !important ... only if you can't without)

.myclass table {
    table-layout: auto !important;
}

.myclass th, .myclass td, .myclass thead th, .myclass tbody td, .myclass tfoot td, .myclass tfoot th {
    width: auto !important;
}

Don't specify css width for table or for table columns. If table content is larger it will go over screen size to.

Convert dataframe column to 1 or 0 for "true"/"false" values and assign to dataframe

Try this, it will convert True into 1 and False into 0:

data.frame$column.name.num  <- as.numeric(data.frame$column.name)

Then you can convert into factor if you want:

data.frame$column.name.num.factor <- as .factor(data.frame$column.name.num)

How can I generate a unique ID in Python?

You might want Python's UUID functions:

21.15. uuid — UUID objects according to RFC 4122

eg:

import uuid
print uuid.uuid4()

7d529dd4-548b-4258-aa8e-23e34dc8d43d

Using group by on multiple columns

Group By X means put all those with the same value for X in the one group.

Group By X, Y means put all those with the same values for both X and Y in the one group.

To illustrate using an example, let's say we have the following table, to do with who is attending what subject at a university:

Table: Subject_Selection

+---------+----------+----------+
| Subject | Semester | Attendee |
+---------+----------+----------+
| ITB001  |        1 | John     |
| ITB001  |        1 | Bob      |
| ITB001  |        1 | Mickey   |
| ITB001  |        2 | Jenny    |
| ITB001  |        2 | James    |
| MKB114  |        1 | John     |
| MKB114  |        1 | Erica    |
+---------+----------+----------+

When you use a group by on the subject column only; say:

select Subject, Count(*)
from Subject_Selection
group by Subject

You will get something like:

+---------+-------+
| Subject | Count |
+---------+-------+
| ITB001  |     5 |
| MKB114  |     2 |
+---------+-------+

...because there are 5 entries for ITB001, and 2 for MKB114

If we were to group by two columns:

select Subject, Semester, Count(*)
from Subject_Selection
group by Subject, Semester

we would get this:

+---------+----------+-------+
| Subject | Semester | Count |
+---------+----------+-------+
| ITB001  |        1 |     3 |
| ITB001  |        2 |     2 |
| MKB114  |        1 |     2 |
+---------+----------+-------+

This is because, when we group by two columns, it is saying "Group them so that all of those with the same Subject and Semester are in the same group, and then calculate all the aggregate functions (Count, Sum, Average, etc.) for each of those groups". In this example, this is demonstrated by the fact that, when we count them, there are three people doing ITB001 in semester 1, and two doing it in semester 2. Both of the people doing MKB114 are in semester 1, so there is no row for semester 2 (no data fits into the group "MKB114, Semester 2")

Hopefully that makes sense.

Android - Set text to TextView

I know its 2 months but yeah

replace your code

Private TextView err;
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_enviar_mensaje);
    err = (TextView)findViewById(R.id.texto);
    err.setText("Escriba su mensaje y luego seleccione el canal.");
}

How to use SQL LIKE condition with multiple values in PostgreSQL?

Use LIKE ANY(ARRAY['AAA%', 'BBB%', 'CCC%']) as per this cool trick @maniek showed earlier today.

How does Facebook Sharer select Images and other metadata when sharing my URL?

When you share for Facebook, you have to add in your html into the head section next meta tags:

<meta property="og:title" content="title" />
<meta property="og:description" content="description" />
<meta property="og:image" content="thumbnail_image" />

And that's it!

Add the button as you should according to what FB tells you.

All the info you need is in www.facebook.com/share/

How does cellForRowAtIndexPath work?

1) The function returns a cell for a table view yes? So, the returned object is of type UITableViewCell. These are the objects that you see in the table's rows. This function basically returns a cell, for a table view. But you might ask, how the function would know what cell to return for what row, which is answered in the 2nd question

2)NSIndexPath is essentially two things-

  • Your Section
  • Your row

Because your table might be divided to many sections and each with its own rows, this NSIndexPath will help you identify precisely which section and which row. They are both integers. If you're a beginner, I would say try with just one section.

It is called if you implement the UITableViewDataSource protocol in your view controller. A simpler way would be to add a UITableViewController class. I strongly recommend this because it Apple has some code written for you to easily implement the functions that can describe a table. Anyway, if you choose to implement this protocol yourself, you need to create a UITableViewCell object and return it for whatever row. Have a look at its class reference to understand re-usablity because the cells that are displayed in the table view are reused again and again(this is a very efficient design btw).

As for when you have two table views, look at the method. The table view is passed to it, so you should not have a problem with respect to that.

AngularJS - How can I do a redirect with a full page load?

After searching and giving hit and trial session I am able to solove it by first specifying url like

$window.location.href = '/#/home/stats';

then reload

$window.location.reload();

How to get the background color code of an element in hex?

Check example link below and click on the div to get the color value in hex.

_x000D_
_x000D_
var color = '';_x000D_
$('div').click(function() {_x000D_
  var x = $(this).css('backgroundColor');_x000D_
  hexc(x);_x000D_
  console.log(color);_x000D_
})_x000D_
_x000D_
function hexc(colorval) {_x000D_
  var parts = colorval.match(/^rgb\((\d+),\s*(\d+),\s*(\d+)\)$/);_x000D_
  delete(parts[0]);_x000D_
  for (var i = 1; i <= 3; ++i) {_x000D_
    parts[i] = parseInt(parts[i]).toString(16);_x000D_
    if (parts[i].length == 1) parts[i] = '0' + parts[i];_x000D_
  }_x000D_
  color = '#' + parts.join('');_x000D_
}
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
<div class='div' style='background-color: #f5b405'>Click me!</div>
_x000D_
_x000D_
_x000D_

Check working example at http://jsfiddle.net/DCaQb/

Format a message using MessageFormat.format() in Java

For everyone that has Android problems in the string.xml, use \'\' instead of single quote.

Maven "build path specifies execution environment J2SE-1.5", even though I changed it to 1.7

I got an error in Eclipse Mars version as "Build path specifies execution environment J2SE-1.5. There are no JREs installed in the workspace that are strictly compatible with this environment.

To resolve this issue, please do the following steps, "Right click on Project Choose Build path Choose Configure Build path Choose Libraries tab Select JRE System Library and click on Edit button Choose workspace default JRE and Finish

Problem will be resolved.

AcquireConnection method call to the connection manager <Excel Connection Manager> failed with error code 0xC0202009

For me, I was accessing my XLS file from a network share. Moving the file for my connection manager to a local folder fixed the issue.

Gradients in Internet Explorer 9

The code I use for all browser gradients:

background: #0A284B;
background: -webkit-gradient(linear, left top, left bottom, from(#0A284B), to(#135887));
background: -webkit-linear-gradient(#0A284B, #135887);
background: -moz-linear-gradient(top, #0A284B, #135887);
background: -ms-linear-gradient(#0A284B, #135887);
background: -o-linear-gradient(#0A284B, #135887);
background: linear-gradient(#0A284B, #135887);
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#0A284B', endColorstr='#135887');
zoom: 1;

You will need to specify a height or zoom: 1 to apply hasLayout to the element for this to work in IE.


Update:

Here is a LESS Mixin (CSS) version for all you LESS users out there:

.gradient(@start, @end) {
    background: mix(@start, @end, 50%);
    filter: ~"progid:DXImageTransform.Microsoft.gradient(startColorStr="@start~", EndColorStr="@end~")";
    background: -webkit-gradient(linear, left top, left bottom, from(@start), to(@end));
    background: -webkit-linear-gradient(@start, @end);
    background: -moz-linear-gradient(top, @start, @end);
    background: -ms-linear-gradient(@start, @end);
    background: -o-linear-gradient(@start, @end);
    background: linear-gradient(@start, @end);
    zoom: 1;
}

How do I set an absolute include path in PHP?

Not directly answering your question but something to remember:

When using includes with allow_url_include on in your ini beware that, when accessing sessions from included files, if from a script you include one file using an absolute file reference and then include a second file from on your local server using a url file reference that they have different variable scope and the same session will not be seen from both included files. The original session won't be seen from the url included file.

from: http://us2.php.net/manual/en/function.include.php#84052

ALTER TABLE DROP COLUMN failed because one or more objects access this column

The @SqlZim's answer is correct but just to explain why this possibly have happened. I've had similar issue and this was caused by very innocent thing: adding default value to a column

ALTER TABLE MySchema.MyTable ADD 
  MyColumn int DEFAULT NULL;

But in the realm of MS SQL Server a default value on a colum is a CONSTRAINT. And like every constraint it has an identifier. And you cannot drop a column if it is used in a CONSTRAINT.

So what you can actually do avoid this kind of problems is always give your default constraints a explicit name, for example:

ALTER TABLE MySchema.MyTable ADD 
  MyColumn int NULL,
  CONSTRAINT DF_MyTable_MyColumn DEFAULT NULL FOR MyColumn;

You'll still have to drop the constraint before dropping the column, but you will at least know its name up front.

Why does printf not flush after the call unless a newline is in the format string?

The stdout stream is line buffered by default, so will only display what's in the buffer after it reaches a newline (or when it's told to). You have a few options to print immediately:

Print to stderrinstead using fprintf (stderr is unbuffered by default):

fprintf(stderr, "I will be printed immediately");

Flush stdout whenever you need it to using fflush:

printf("Buffered, will be flushed");
fflush(stdout); // Will now print everything in the stdout buffer

Edit: From Andy Ross's comment below, you can also disable buffering on stdout by using setbuf:

setbuf(stdout, NULL);

or its secure version setvbuf as explained here

setvbuf(stdout, NULL, _IONBF, 0); 

When should I really use noexcept?

As I keep repeating these days: semantics first.

Adding noexcept, noexcept(true) and noexcept(false) is first and foremost about semantics. It only incidentally condition a number of possible optimizations.

As a programmer reading code, the presence of noexcept is akin to that of const: it helps me better grok what may or may not happen. Therefore, it is worthwhile spending some time thinking about whether or not you know if the function will throw. For a reminder, any kind of dynamic memory allocation may throw.


Okay, now on to the possible optimizations.

The most obvious optimizations are actually performed in the libraries. C++11 provides a number of traits that allows knowing whether a function is noexcept or not, and the Standard Library implementation themselves will use those traits to favor noexcept operations on the user-defined objects they manipulate, if possible. Such as move semantics.

The compiler may only shave a bit of fat (perhaps) from the exception handling data, because it has to take into account the fact that you may have lied. If a function marked noexcept does throw, then std::terminate is called.

These semantics were chosen for two reasons:

  • immediately benefiting from noexcept even when dependencies do not use it already (backward compatibility)
  • allowing the specification of noexcept when calling functions that may theoretically throw, but are not expected to for the given arguments

java create date object using a value string

Try this :-

try{
        String valuee="25/04/2013";
        Date currentDate =new SimpleDateFormat("dd/MM/yyyy").parse(valuee);
        System.out.println("Date is ::"+currentDate);
        }catch(Exception e){
            System.out.println("Error::"+e);
            e.printStackTrace();
        }

Output:-

   Date is ::Thu Apr 25 00:00:00 GMT+05:30 2013

Your value should be proper format.

In your question also you have asked for this below :-

   Date currentDate = new Date(value);

This style of date constructor is already deprecated.So, its no more use.Being we know that Date has 6 constructor.Read more

init-param and context-param

Consider the below definition in web.xml

<servlet>
    <servlet-name>HelloWorld</servlet-name>
    <servlet-class>TestServlet</servlet-class>
    <init-param>
        <param-name>myprop</param-name>
        <param-value>value</param-value>
    </init-param>
</servlet>

You can see that init-param is defined inside a servlet element. This means it is only available to the servlet under declaration and not to other parts of the web application. If you want this parameter to be available to other parts of the application say a JSP this needs to be explicitly passed to the JSP. For instance passed as request.setAttribute(). This is highly inefficient and difficult to code.

So if you want to get access to global values from anywhere within the application without explicitly passing those values, you need to use Context Init parameters.

Consider the following definition in web.xml

 <web-app>
      <context-param>
           <param-name>myprop</param-name>
           <param-value>value</param-value>
      </context-param>
 </web-app>

This context param is available to all parts of the web application and it can be retrieved from the Context object. For instance, getServletContext().getInitParameter(“dbname”);

From a JSP you can access the context parameter using the application implicit object. For example, application.getAttribute(“dbname”);

javax vs java package

Javax used to be only for extensions. Yet later sun added it to the java libary forgetting to remove the x. Developers started making code with javax. Yet later on in time suns decided to change it to java. Developers didn't like the idea because they're code would be ruined... so javax was kept.