Programs & Examples On #Unmount

How to unmount, unrender or remove a component, from itself in a React/Redux/Typescript notification message

Just like that nice warning you got, you are trying to do something that is an Anti-Pattern in React. This is a no-no. React is intended to have an unmount happen from a parent to child relationship. Now if you want a child to unmount itself, you can simulate this with a state change in the parent that is triggered by the child. let me show you in code.

class Child extends React.Component {
    constructor(){}
    dismiss() {
        this.props.unmountMe();
    } 
    render(){
        // code
    }
}

class Parent ...
    constructor(){
        super(props)
        this.state = {renderChild: true};
        this.handleChildUnmount = this.handleChildUnmount.bind(this);
    }
    handleChildUnmount(){
        this.setState({renderChild: false});
    }
    render(){
        // code
        {this.state.renderChild ? <Child unmountMe={this.handleChildUnmount} /> : null}
    }

}

this is a very simple example. but you can see a rough way to pass through to the parent an action

That being said you should probably be going through the store (dispatch action) to allow your store to contain the correct data when it goes to render

I've done error/status messages for two separate applications, both went through the store. It's the preferred method... If you'd like I can post some code as to how to do that.

EDIT: Here is how I set up a notification system using React/Redux/Typescript

Few things to note first. this is in typescript so you would need to remove the type declarations :)

I am using the npm packages lodash for operations, and classnames (cx alias) for inline classname assignment.

The beauty of this setup is I use a unique identifier for each notification when the action creates it. (e.g. notify_id). This unique ID is a Symbol(). This way if you want to remove any notification at any point in time you can because you know which one to remove. This notification system will let you stack as many as you want and they will go away when the animation is completed. I am hooking into the animation event and when it finishes I trigger some code to remove the notification. I also set up a fallback timeout to remove the notification just in case the animation callback doesn't fire.

notification-actions.ts

import { USER_SYSTEM_NOTIFICATION } from '../constants/action-types';

interface IDispatchType {
    type: string;
    payload?: any;
    remove?: Symbol;
}

export const notifySuccess = (message: any, duration?: number) => {
    return (dispatch: Function) => {
        dispatch({ type: USER_SYSTEM_NOTIFICATION, payload: { isSuccess: true, message, notify_id: Symbol(), duration } } as IDispatchType);
    };
};

export const notifyFailure = (message: any, duration?: number) => {
    return (dispatch: Function) => {
        dispatch({ type: USER_SYSTEM_NOTIFICATION, payload: { isSuccess: false, message, notify_id: Symbol(), duration } } as IDispatchType);
    };
};

export const clearNotification = (notifyId: Symbol) => {
    return (dispatch: Function) => {
        dispatch({ type: USER_SYSTEM_NOTIFICATION, remove: notifyId } as IDispatchType);
    };
};

notification-reducer.ts

const defaultState = {
    userNotifications: []
};

export default (state: ISystemNotificationReducer = defaultState, action: IDispatchType) => {
    switch (action.type) {
        case USER_SYSTEM_NOTIFICATION:
            const list: ISystemNotification[] = _.clone(state.userNotifications) || [];
            if (_.has(action, 'remove')) {
                const key = parseInt(_.findKey(list, (n: ISystemNotification) => n.notify_id === action.remove));
                if (key) {
                    // mutate list and remove the specified item
                    list.splice(key, 1);
                }
            } else {
                list.push(action.payload);
            }
            return _.assign({}, state, { userNotifications: list });
    }
    return state;
};

app.tsx

in the base render for your application you would render the notifications

render() {
    const { systemNotifications } = this.props;
    return (
        <div>
            <AppHeader />
            <div className="user-notify-wrap">
                { _.get(systemNotifications, 'userNotifications') && Boolean(_.get(systemNotifications, 'userNotifications.length'))
                    ? _.reverse(_.map(_.get(systemNotifications, 'userNotifications', []), (n, i) => <UserNotification key={i} data={n} clearNotification={this.props.actions.clearNotification} />))
                    : null
                }
            </div>
            <div className="content">
                {this.props.children}
            </div>
        </div>
    );
}

user-notification.tsx

user notification class

/*
    Simple notification class.

    Usage:
        <SomeComponent notifySuccess={this.props.notifySuccess} notifyFailure={this.props.notifyFailure} />
        these two functions are actions and should be props when the component is connect()ed

    call it with either a string or components. optional param of how long to display it (defaults to 5 seconds)
        this.props.notifySuccess('it Works!!!', 2);
        this.props.notifySuccess(<SomeComponentHere />, 15);
        this.props.notifyFailure(<div>You dun goofed</div>);

*/

interface IUserNotifyProps {
    data: any;
    clearNotification(notifyID: symbol): any;
}

export default class UserNotify extends React.Component<IUserNotifyProps, {}> {
    public notifyRef = null;
    private timeout = null;

    componentDidMount() {
        const duration: number = _.get(this.props, 'data.duration', '');
       
        this.notifyRef.style.animationDuration = duration ? `${duration}s` : '5s';

        
        // fallback incase the animation event doesn't fire
        const timeoutDuration = (duration * 1000) + 500;
        this.timeout = setTimeout(() => {
            this.notifyRef.classList.add('hidden');
            this.props.clearNotification(_.get(this.props, 'data.notify_id') as symbol);
        }, timeoutDuration);

        TransitionEvents.addEndEventListener(
            this.notifyRef,
            this.onAmimationComplete
        );
    }
    componentWillUnmount() {
        clearTimeout(this.timeout);

        TransitionEvents.removeEndEventListener(
            this.notifyRef,
            this.onAmimationComplete
        );
    }
    onAmimationComplete = (e) => {
        if (_.get(e, 'animationName') === 'fadeInAndOut') {
            this.props.clearNotification(_.get(this.props, 'data.notify_id') as symbol);
        }
    }
    handleCloseClick = (e) => {
        e.preventDefault();
        this.props.clearNotification(_.get(this.props, 'data.notify_id') as symbol);
    }
    assignNotifyRef = target => this.notifyRef = target;
    render() {
        const {data, clearNotification} = this.props;
        return (
            <div ref={this.assignNotifyRef} className={cx('user-notification fade-in-out', {success: data.isSuccess, failure: !data.isSuccess})}>
                {!_.isString(data.message) ? data.message : <h3>{data.message}</h3>}
                <div className="close-message" onClick={this.handleCloseClick}>+</div>
            </div>
        );
    }
}

axios post request to send form data

import axios from "axios";
import qs from "qs";   

const url = "https://yourapplicationbaseurl/api/user/authenticate";
    let data = {
      Email: "[email protected]",
      Password: "Admin@123"
    };
    let options = {
      method: "POST",
      headers: { "content-type": "application/x-www-form-urlencoded" },
      data: qs.stringify(data),
      url
    };
    axios(options)
      .then(res => {
        console.log("yeh we have", res.data);
      })
      .catch(er => {
        console.log("no data sorry ", er);
      });
  };

Cron job every three days

0 0 * * * [ $(($((date +%-j- 1)) % 3)) == 0 ] && script

Get the day of the year from date, offset by 1 to start at 0, check if it is modulo three.

How to check if a string is a number?

if ( strlen(str) == strlen( itoa(atoi(str)) ) ) {
    //its an integer
}

As atoi converts string to number skipping letters other than digits, if there was no other than digits its string length has to be the same as the original. This solution is better than innumber() if the check is for integer.

How to add external library in IntelliJ IDEA?

Intellij IDEA 15: File->Project Structure...->Project Settings->Libraries

PHP fopen() Error: failed to open stream: Permission denied

[function.fopen]: failed to open stream

If you have access to your php.ini file, try enabling Fopen. Find the respective line and set it to be "on": & if in wp e.g localhost/wordpress/function.fopen in the php.ini :

allow_url_fopen = off
should bee this 
allow_url_fopen = On

And add this line below it:
allow_url_include = off
should bee this 
allow_url_include = on

How to send email from Terminal?

If you want to attach a file on Linux

echo 'mail content' | mailx -s 'email subject' -a attachment.txt [email protected]

Create text file and fill it using bash

#!/bin/bash
file_location=/home/test/$1.json
if [ -e $policy ]; then
  echo "File $1.json already exists!"
else
  cat > $file_location <<EOF
{
      "contact": {
          "name": "xyz",
          "phonenumber":   "xxx-xxx-xxxx"
      }
    }
EOF
fi

This code checks if the given JSON file of the user is present in test home directory or not. If it's not present it will create it with the content. You can modify the file location and content according to your needs.

UITableViewCell Selected Background Color on Multiple Selection

Swift 4.2

For multiple selections you need to set the UITableView property allowsMultipleSelection to true.

myTableView.allowsMultipleSelection = true

In case you subclassed the UITableViewCell, you override setSelected(_ selected: Bool, animated: Bool) method in your custom cell class.

 override func setSelected(_ selected: Bool, animated: Bool) {
     super.setSelected(selected, animated: animated)

     if selected {
         contentView.backgroundColor = UIColor.green
     } else {
         contentView.backgroundColor = UIColor.blue
     }
 }

fatal: Not a valid object name: 'master'

First off, when you create a "bare repository", you're not going to be doing any work with it (it doesn't contain a working copy, so the git branch command is not useful).

Now, the reason you wouldn't have a master branch even after doing a git init is that there are no commits: when you create your first commit, you will then have a master branch.

How can I fill out a Python string with spaces?

Just remove the 0 and it will add space instead:

>>> print  "'%6d'"%4

Programmatically Creating UILabel

For swift

var label = UILabel(frame: CGRect(x: 0, y: 0, width: 250, height: 50))
label.textAlignment = .left
label.text = "This is a Label"
self.view.addSubview(label)

Node.js, can't open files. Error: ENOENT, stat './path/to/file'

Paths specified with a . are relative to the current working directory, not relative to the script file. So the file might be found if you run node app.js but not if you run node folder/app.js. The only exception to this is require('./file') and that is only possible because require exists per-module and thus knows what module it is being called from.

To make a path relative to the script, you must use the __dirname variable.

var path = require('path');

path.join(__dirname, 'path/to/file')

or potentially

path.join(__dirname, 'path', 'to', 'file')

Error in Python script "Expected 2D array, got 1D array instead:"?

With one feature my Dataframe list converts to a Series. I had to convert it back to a Dataframe list and it worked.

if type(X) is Series:
    X = X.to_frame()

SQL Server 2008 Row Insert and Update timestamps

As an alternative to using a trigger, you might like to consider creating a stored procedure to handle the INSERTs that takes most of the columns as arguments and gets the CURRENT_TIMESTAMP which it includes in the final INSERT to the database. You could do the same for the CREATE. You may also be able to set things up so that users cannot execute INSERT and CREATE statements other than via the stored procedures.

I have to admit that I haven't actually done this myself so I'm not at all sure of the details.

Can I change the height of an image in CSS :before/:after pseudo-elements?

Yes, the original question was asked eight years ago, but it's actually relevant today as its always been. Now, I've been going from pillar to post over this issue of ::before, for about a week ::after, and its been driving me round the bend.

From this page, and others on the subject - I've finally put it together and sized an image down in the pseudo tag.

** Running note .colnav is just my container class, that holds an < UL > and < LI > set of tags with a set of < a hrefs inside.

Below is the code (complete)

.colnav li.nexus-button a:hover:before {   
    background-image: url('/images/fleur-de-lis.png');
    background-size: 90px 20px;
    background-repeat: no-repeat;
    width: 130px;
    height: 20px;
    margin-left: -120px;
    margin-top: -3px;
    transform: scale(1.5);
    content: "";
    position: absolute;
}

The image file was (is) 120 x 80, and the picture got reduced right down to 90x 20, where it then fitted quite nicely behind the html href tag, and it all came together with that position: absolute statement at the end.

Threading Example in Android

Here is a simple threading example for Android. It's very basic but it should help you to get a perspective.

Android code - Main.java

package test12.tt;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class Test12Activity extends Activity {

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        final TextView txt1 = (TextView) findViewById(R.id.sm);

        new Thread(new Runnable() { 
            public void run(){        
            txt1.setText("Thread!!");
            }
        }).start();

    }    
}

Android application xml - main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

    <TextView  
    android:id = "@+id/sm"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"/>

</LinearLayout>

Auto Increment after delete in MySQL

here is a function that fix your problem

    public static void fixID(Connection conn, String table) {

    try {
        Statement myStmt = conn.createStatement();
        ResultSet myRs;
        int i = 1, id = 1, n = 0;
        boolean b;
        String sql;

        myRs = myStmt.executeQuery("select max(id) from " + table);
        if (myRs.next()) {
            n = myRs.getInt(1);
        }
        while (i <= n) {
            b = false;
            myRs = null;
            while (!b) {
                myRs = myStmt.executeQuery("select id from " + table + " where id=" + id);
                if (!myRs.next()) {
                    id++;
                } else {
                    b = true;
                }
            }

            sql = "UPDATE " + table + " set id =" + i + " WHERE id=" + id;
            myStmt.execute(sql);
            i++;
            id++;
        }

    } catch (SQLException e) {
        e.printStackTrace();
    }
}

AngularJs: How to check for changes in file input fields?

Another interesting way to listen file input changes is with a watch over the ng-model attribute of the input file. Off course FileModel is a custom directive.

Like this:

HTML -> <input type="file" file-model="change.fnEvidence">

JS Code ->

$scope.$watch('change.fnEvidence', function() {
                    alert("has changed");
                });

Hope it can helps someone.

Asyncio.gather vs asyncio.wait

asyncio.wait is more low level than asyncio.gather.

As the name suggests, asyncio.gather mainly focuses on gathering the results. It waits on a bunch of futures and returns their results in a given order.

asyncio.wait just waits on the futures. And instead of giving you the results directly, it gives done and pending tasks. You have to manually collect the values.

Moreover, you could specify to wait for all futures to finish or just the first one with wait.

Converting RGB to grayscale/intensity

I found that this publication referenced in an answer to a previous similar question. It is very helpful:

http://cadik.posvete.cz/color_to_gray_evaluation/

It shows 'tons' of different methods to generate grayscale images with different outcomes!

Is there a way to reduce the size of the git folder?

git clean -d -f -i is the best way to do it.

This will help to clean in a more controlled manner.

-i stands for interactive.

Char Comparison in C

In C the char type has a numeric value so the > operator will work just fine for example

#include <stdio.h>
main() {

    char a='z';

    char b='h';

    if ( a > b ) {
        printf("%c greater than %c\n",a,b);
    }
}

What are "named tuples" in Python?

What is namedtuple ?

As the name suggests, namedtuple is a tuple with name. In standard tuple, we access the elements using the index, whereas namedtuple allows user to define name for elements. This is very handy especially processing csv (comma separated value) files and working with complex and large dataset, where the code becomes messy with the use of indices (not so pythonic).

How to use them ?

>>>from collections import namedtuple
>>>saleRecord = namedtuple('saleRecord','shopId saleDate salesAmout totalCustomers')
>>>
>>>
>>>#Assign values to a named tuple 
>>>shop11=saleRecord(11,'2015-01-01',2300,150) 
>>>shop12=saleRecord(shopId=22,saleDate="2015-01-01",saleAmout=1512,totalCustomers=125)

Reading

>>>#Reading as a namedtuple
>>>print("Shop Id =",shop12.shopId)
12
>>>print("Sale Date=",shop12.saleDate)
2015-01-01
>>>print("Sales Amount =",shop12.salesAmount)
1512
>>>print("Total Customers =",shop12.totalCustomers)
125

Interesting Scenario in CSV Processing :

from csv import reader
from collections import namedtuple

saleRecord = namedtuple('saleRecord','shopId saleDate totalSales totalCustomers')
fileHandle = open("salesRecord.csv","r")
csvFieldsList=csv.reader(fileHandle)
for fieldsList in csvFieldsList:
    shopRec = saleRecord._make(fieldsList)
    overAllSales += shopRec.totalSales;

print("Total Sales of The Retail Chain =",overAllSales)

@HostBinding and @HostListener: what do they do and what are they for?

Summary:

  • @HostBinding: This decorator binds a class property to a property of the host element.
  • @HostListener: This decorator binds a class method to an event of the host element.

Example:

import { Component, HostListener, HostBinding } from '@angular/core';

@Component({
  selector: 'app-root',
  template: `<p>This is nice text<p>`,
})
export class AppComponent  {

  @HostBinding('style.color') color; 

  @HostListener('click')
  onclick() {
    this.color =  'blue';
  }

}

In the above example the following occurs:

  • An event listener is added to the click event which will be fired when a click event occurs anywhere within the component
  • The color property in our AppComponent class is bound to the style.color property on the component. So whenever the color property is updated so will the style.color property of our component
  • The result will be that whenever someone clicks on the component the color will be updated.

Usage in @Directive:

Although it can be used on component these decorators are often used in a attribute directives. When used in an @Directive the host changes the element on which the directive is placed. For example take a look at this component template:

<p p_Dir>some paragraph</p>

Here p_Dir is a directive on the <p> element. When @HostBinding or @HostListener is used within the directive class the host will now refer to the <p>.

IntelliJ inspection gives "Cannot resolve symbol" but still compiles code

Had trouble importing standard java libraries such as java.beans.*

Fixed it on my Redhat 7 system by pointing it to the correct JRE path.

File->ProjectStructure->SDKs->1.8 Changed 'JDK home path:' to /usr/lib/jvm/java-1.8.0-openjdk-1.8.0161-2.b14.el7.x86_64 instead of /usr/lib/jvm/java-1.8.0-openjdk-1.8.0161-2.b14.el7_4.x86_64

The former path to jdk(with the _4 difference in path) hardly had anything in it. It was missing many java libraries.

Share Text on Facebook from Android App via ACTION_SEND

06/2013 :

  • This is a bug from Facebook, not your code
  • Facebook will NOT fix this bug, they say it is "by design" that they broke the Android share system : https://developers.facebook.com/bugs/332619626816423
  • use the SDK or share only URL.
  • Tips: you could cheat a little using the web page title as text for the post.

Running script upon login mac

Follow this:

  • start Automator.app
  • select Application
  • click Show library in the toolbar (if hidden)
  • add Run shell script (from the Actions/Utilities)
  • copy & paste your script into the window
  • test it
  • save somewhere (for example you can make an Applications folder in your HOME, you will get an your_name.app)

  • go to System Preferences -> Accounts -> Login items

  • add this app
  • test & done ;)

EDIT:

I've recently earned a "Good answer" badge for this answer. While my solution is simple and working, the cleanest way to run any program or shell script at login time is described in @trisweb's answer, unless, you want interactivity.

With automator solution you can do things like next: automator screenshot login application

so, asking to run a script or quit the app, asking passwords, running other automator workflows at login time, conditionally run applications at login time and so on...

Android Studio Gradle: Error:Execution failed for task ':app:processDebugGoogleServices'. > No matching client found for package

Open google-services.json in android studio we can see a json object, and contain following items in 'client' jsonarray

"client_id": "android:your package name", "package_name": "your package name",

Please verify your package and proceed.

How to join three table by laravel eloquent model

With Eloquent its very easy to retrieve relational data. Checkout the following example with your scenario in Laravel 5.

We have three models:

1) Article (belongs to user and category)

2) Category (has many articles)

3) User (has many articles)


1) Article.php

<?php

namespace App\Models;
 use Eloquent;

class Article extends Eloquent{

    protected $table = 'articles';

    public function user()
    {
        return $this->belongsTo('App\Models\User');
    }

    public function category()
    {
        return $this->belongsTo('App\Models\Category');
    }

}

2) Category.php

<?php

namespace App\Models;

use Eloquent;

class Category extends Eloquent
{
    protected $table = "categories";

    public function articles()
    {
        return $this->hasMany('App\Models\Article');
    }

}

3) User.php

<?php

namespace App\Models;
use Eloquent;

class User extends Eloquent
{
    protected $table = 'users';

    public function articles()
    {
        return $this->hasMany('App\Models\Article');
    }

}

You need to understand your database relation and setup in models. User has many articles. Category has many articles. Articles belong to user and category. Once you setup the relationships in Laravel, it becomes easy to retrieve the related information.

For example, if you want to retrieve an article by using the user and category, you would need to write:

$article = \App\Models\Article::with(['user','category'])->first();

and you can use this like so:

//retrieve user name 
$article->user->user_name  

//retrieve category name 
$article->category->category_name

In another case, you might need to retrieve all the articles within a category, or retrieve all of a specific user`s articles. You can write it like this:

$categories = \App\Models\Category::with('articles')->get();

$users = \App\Models\Category::with('users')->get();

You can learn more at http://laravel.com/docs/5.0/eloquent

System.web.mvc missing

Easiest way to solve this problem is install ASP.NET MVC 3 from Web Platforms installer.

enter image description here

http://www.microsoft.com/web/downloads/

Or by using Nuget command

Install-Package Microsoft.AspNet.Mvc -Version 3.0.50813.1

How to see the values of a table variable at debug time in T-SQL?

Sorry guys, I'm a little late to the party but for anyone that stumbles across this question at a later date, I've found the easiest way to do this in a stored procedure is to:

  1. Create a new query with any procedure parameters declared and initialised at the top.
  2. Paste in the body of your procedure.
  3. Add a good old fashioned select query immediately after your table variable is initialised with data.
  4. If 3. is not the last statement in the procedure, set a breakpoint on the same line, start debugging and continue straight to your breakpoint.
  5. Profit!!

messi19's answer should be the accepted one IMHO, since it is simpler than mine and does the job most of the time, but if you're like me and have a table variable inside a loop that you want to inspect, this does the job nicely without too much effort or external SSMS plugins.

Display an image with Python

Solution for Jupyter notebook PIL image visualization with arbitrary number of images:

def show(*imgs, **kwargs):
    '''Show in Jupyter notebook one or sequence of PIL images in a row. figsize - optional parameter, controlling size of the image.
    Examples:
    show(img)
    show(img1,img2,img3)
    show(img1,img2,figsize=[8,8])
    '''
    
    if 'figsize' not in kwargs:
        figsize = [9,9]
    else:
        figsize = kwargs['figsize']
    
    fig, ax = plt.subplots(1,len(imgs),figsize=figsize)
    if len(imgs)==1:
        ax=[ax]
    
    for num,img in enumerate(imgs):
        ax[num].imshow(img)
        ax[num].axis('off')
        
    tight_layout()

Prevent onmouseout when hovering child element of the parent absolute div WITHOUT jQuery

If you added (or have) a CSS class or id to the parent element, then you can do something like this:

<div id="parent">
  <div>
  </div>
</div>

JavaScript:
document.getElementById("parent").onmouseout = function(e) {
  e = e ? e : window.event //For IE
  if(e.target.id == "parent") {
    //Do your stuff
  }
}

So stuff only gets executed when the event is on the parent div.

Loop through all elements in XML using NodeList

    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
    DocumentBuilder db = dbf.newDocumentBuilder();
    Document dom = db.parse("file.xml");
    Element docEle = dom.getDocumentElement();
    NodeList nl = docEle.getChildNodes();
    int length = nl.getLength();
    for (int i = 0; i < length; i++) {
        if (nl.item(i).getNodeType() == Node.ELEMENT_NODE) {
            Element el = (Element) nl.item(i);
            if (el.getNodeName().contains("staff")) {
                String name = el.getElementsByTagName("name").item(0).getTextContent();
                String phone = el.getElementsByTagName("phone").item(0).getTextContent();
                String email = el.getElementsByTagName("email").item(0).getTextContent();
                String area = el.getElementsByTagName("area").item(0).getTextContent();
                String city = el.getElementsByTagName("city").item(0).getTextContent();
            }
        }
    }

Iterate over all children and nl.item(i).getNodeType() == Node.ELEMENT_NODE is used to filter text nodes out. If there is nothing else in XML what remains are staff nodes.

For each node under stuff (name, phone, email, area, city)

 el.getElementsByTagName("name").item(0).getTextContent(); 

el.getElementsByTagName("name") will extract the "name" nodes under stuff, .item(0) will get you the first node and .getTextContent() will get the text content inside.

Edit: Since we have jackson I would do this in a different way. Define a pojo for the object:

public class Staff {
    private String name;
    private String phone;
    private String email;
    private String area;
    private String city;
...getters setters
}

Then using jackson:

    JsonNode root = new XmlMapper().readTree(xml.getBytes());
    ObjectMapper mapper = new ObjectMapper();
    root.forEach(node -> consume(node, mapper));



private void consume(JsonNode node, ObjectMapper mapper) {
    try {
        Staff staff = mapper.treeToValue(node, Staff.class);
        //TODO your job with staff
    } catch (JsonProcessingException e) {
        e.printStackTrace();
    }
}

Compiling C++11 with g++

You can refer to following link for which features are supported in particular version of compiler. It has an exhaustive list of feature support in compiler. Looks GCC follows standard closely and implements before any other compiler.

Regarding your question you can compile using

  1. g++ -std=c++11 for C++11
  2. g++ -std=c++14 for C++14
  3. g++ -std=c++17 for C++17
  4. g++ -std=c++2a for C++20, although all features of C++20 are not yet supported refer this link for feature support list in GCC.

The list changes pretty fast, keep an eye on the list, if you are waiting for particular feature to be supported.

Maintaining href "open in new tab" with an onClick handler in React

Most Secure Solution, JS only

As mentioned by alko989, there is a major security flaw with _blank (details here).

To avoid it from pure JS code:

const openInNewTab = (url) => {
  const newWindow = window.open(url, '_blank', 'noopener,noreferrer')
  if (newWindow) newWindow.opener = null
}

Then add to your onClick

onClick={() => openInNewTab('https://stackoverflow.com')}

The third param can also take these optional values, based on your needs.

How to calculate DATE Difference in PostgreSQL?

a simple way would be to cast the dates into timestamps and take their difference and then extract the DAY part.

if you want real difference

select extract(day from 'DATE_A'::timestamp - 'DATE_B':timestamp);

if you want absolute difference

select abs(extract(day from 'DATE_A'::timestamp - 'DATE_B':timestamp));

Use FontAwesome or Glyphicons with css :before

Re: using icon in :before – recent Font Awesome builds include the .fa-icon() mixin for SASS and LESS. This will automatically include the font-family as well as some rendering tweaks (e.g. -webkit-font-smoothing). Thus you can do, e.g.:

// Add "?" icon to header.
h1:before {
    .fa-icon();
    content: "\f059";
}

nodejs - first argument must be a string or Buffer - when using response.write with http.request

And there is another possibility (not in this case) when working with ajax(XMLhttpRequest), while sending information back to the client end you should use res.send(responsetext) instead of res.end(responsetext)

Objective-C implicit conversion loses integer precision 'NSUInteger' (aka 'unsigned long') to 'int' warning

Contrary to Martin's answer, casting to int (or ignoring the warning) isn't always safe even if you know your array doesn't have more than 2^31-1 elements. Not when compiling for 64-bit.

For example:

NSArray *array = @[@"a", @"b", @"c"];

int i = (int) [array indexOfObject:@"d"];
// indexOfObject returned NSNotFound, which is NSIntegerMax, which is LONG_MAX in 64 bit.
// We cast this to int and got -1.
// But -1 != NSNotFound. Trouble ahead!

if (i == NSNotFound) {
    // thought we'd get here, but we don't
    NSLog(@"it's not here");
}
else {
    // this is what actually happens
    NSLog(@"it's here: %d", i);

    // **** crash horribly ****
    NSLog(@"the object is %@", array[i]);
}

Creating executable files in Linux

Make file executable:

chmod +x file

Find location of perl:

which perl

This should return something like

/bin/perl sometimes /usr/local/bin

Then in the first line of your script add:

#!"path"/perl with path from above e.g.

#!/bin/perl

Then you can execute the file

./file

There may be some issues with the PATH, so you may want to change that as well ...

How to debug external class library projects in visual studio?

Assume the path of

Project A

C:\Projects\ProjectA

Project B

C:\Projects\ProjectB

and the dll of ProjectB is in

C:\Projects\ProjectB\bin\Debug\

To debug into ProjectB from ProjectA, do the following

  1. Copy B's dll with dll's .PDB to the ProjectA's compiling directory.
  2. Now debug ProjectA. When code reaches the part where you need to call dll's method or events etc while debugging, press F11 to step into the dll's code.

NOTE : DO NOT MISS TO COPY THE .PDB FILE

Objective-C and Swift URL encoding

To escape the characters you want is a little more work.

Example code

iOS7 and above:

NSString *unescaped = @"http://www";
NSString *escapedString = [unescaped stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLHostAllowedCharacterSet]];
NSLog(@"escapedString: %@", escapedString);

NSLog output:

escapedString: http%3A%2F%2Fwww

The following are useful URL encoding character sets:

URLFragmentAllowedCharacterSet  "#%<>[\]^`{|}
URLHostAllowedCharacterSet      "#%/<>?@\^`{|}
URLPasswordAllowedCharacterSet  "#%/:<>?@[\]^`{|}
URLPathAllowedCharacterSet      "#%;<>?[\]^`{|}
URLQueryAllowedCharacterSet     "#%<>[\]^`{|}
URLUserAllowedCharacterSet      "#%/:<>?@[\]^`

Creating a characterset combining all of the above:

NSCharacterSet *URLCombinedCharacterSet = [[NSCharacterSet characterSetWithCharactersInString:@" \"#%/:<>?@[\\]^`{|}"] invertedSet];

Creating a Base64

In the case of Base64 characterset:

NSCharacterSet *URLBase64CharacterSet = [[NSCharacterSet characterSetWithCharactersInString:@"/+=\n"] invertedSet];

For Swift 3.0:

var escapedString = originalString.addingPercentEncoding(withAllowedCharacters:.urlHostAllowed)

For Swift 2.x:

var escapedString = originalString.stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.URLHostAllowedCharacterSet())

Note: stringByAddingPercentEncodingWithAllowedCharacters will also encode UTF-8 characters needing encoding.

Pre iOS7 use Core Foundation
Using Core Foundation With ARC:

NSString *escapedString = (NSString *)CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(
    NULL,
   (__bridge CFStringRef) unescaped,
    NULL,
    CFSTR("!*'();:@&=+$,/?%#[]\" "),
    kCFStringEncodingUTF8));

Using Core Foundation Without ARC:

NSString *escapedString = (NSString *)CFURLCreateStringByAddingPercentEscapes(
    NULL,
   (CFStringRef)unescaped,
    NULL,
    CFSTR("!*'();:@&=+$,/?%#[]\" "),
    kCFStringEncodingUTF8);

Note: -stringByAddingPercentEscapesUsingEncoding will not produce the correct encoding, in this case it will not encode anything returning the same string.

stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding encodes 14 characrters:

`#%^{}[]|\"<> plus the space character as percent escaped.

testString:

" `~!@#$%^&*()_+-={}[]|\\:;\"'<,>.?/AZaz"  

encodedString:

"%20%60~!@%23$%25%5E&*()_+-=%7B%7D%5B%5D%7C%5C:;%22'%3C,%3E.?/AZaz"  

Note: consider if this set of characters meet your needs, if not change them as needed.

RFC 3986 characters requiring encoding (% added since it is the encoding prefix character):

"!#$&'()*+,/:;=?@[]%"

Some "unreserved characters" are additionally encoded:

"\n\r \"%-.<>\^_`{|}~"

How to find if div with specific id exists in jQuery?

if($("#id").length) /*exists*/

if(!$("#id").length) /*doesn't exist*/

Bootstrap 4 img-circle class not working

In Bootstrap 4 it was renamed to .rounded-circle

Usage :

<div class="col-xs-7">
    <img src="img/gallery2.JPG" class="rounded-circle" alt="HelPic>
</div>

See migration docs from bootstrap.

How to run a program in Atom Editor?

You can run specific lines of script by highlighting them and clicking shift + ctrl + b

You can also use command line by going to the root folder and writing: $ node nameOfFile.js

How do I simulate placeholder functionality on input date field?

I'm using the following CSS only trick:

_x000D_
_x000D_
  input[type="date"]:before {_x000D_
    content: attr(placeholder) !important;_x000D_
    color: #aaa;_x000D_
    margin-right: 0.5em;_x000D_
  }_x000D_
  input[type="date"]:focus:before,_x000D_
  input[type="date"]:valid:before {_x000D_
    content: "";_x000D_
  }
_x000D_
<input type="date" placeholder="Choose a Date" />
_x000D_
_x000D_
_x000D_

"Python version 2.7 required, which was not found in the registry" error when attempting to install netCDF4 on Windows 8

Check for the 32/64 bit you trying to install. both python interpreter and your app which trying to use python might be of different bit.

Make an Android button change background on click through XML

In the latest version of the SDK, you would use the setBackgroundResource method.

public void onClick(View v) {
   if(v == ButtonName) {
     ButtonName.setBackgroundResource(R.drawable.ImageResource);
   }
}

How to playback MKV video in web browser?

HTML5 and the VLC web plugin were a no go for me but I was able to get this work using the following setup:

DivX Web Player (NPAPI browsers only)

AC3 Audio Decoder

And here is the HTML:

<embed id="divxplayer" type="video/divx" width="1024" height="768" 
src ="path_to_file" autoPlay=\"true\" 
pluginspage=\"http://go.divx.com/plugin/download/\"></embed>

The DivX player seems to allow for a much wider array of video and audio options than the native HTML5, so far I am very impressed by it.

How many socket connections can a web server handle?

It looks like the answer is at least 12 million if you have a beefy server, your server software is optimized for it, you have enough clients. If you test from one client to one server, the number of port numbers on the client will be one of the obvious resource limits (Each TCP connection is defined by the unique combination of IP and port number at the source and destination).

(You need to run multiple clients as otherwise you hit the 64K limit on port numbers first)

When it comes down to it, this is a classic example of the witticism that "the difference between theory and practise is much larger in practise than in theory" - in practise achieving the higher numbers seems to be a cycle of a. propose specific configuration/architecture/code changes, b. test it till you hit a limit, c. Have I finished? If not then d. work out what was the limiting factor, e. go back to step a (rinse and repeat).

Here is an example with 2 million TCP connections onto a beefy box (128GB RAM and 40 cores) running Phoenix http://www.phoenixframework.org/blog/the-road-to-2-million-websocket-connections - they ended up needing 50 or so reasonably significant servers just to provide the client load (their initial smaller clients maxed out to early, eg "maxed our 4core/15gb box @ 450k clients").

Here is another reference for go this time at 10 million: http://goroutines.com/10m.

This appears to be java based and 12 million connections: https://mrotaru.wordpress.com/2013/06/20/12-million-concurrent-connections-with-migratorydata-websocket-server/

Why my regexp for hyphenated words doesn't work?

This regex should do it.

\b[a-z]+-[a-z]+\b 

\b indicates a word-boundary.

jQuery: go to URL with target="_blank"

Question: How can I open the href in the new window or tab with jQuery?

var url = $(this).attr('href').attr('target','_blank');

How to read input from console in a batch file?

The code snippet in the linked proposed duplicate reads user input.

ECHO A current build of Test Harness exists.
set /p delBuild=Delete preexisting build [y/n]?: 

The user can type as many letters as they want, and it will go into the delBuild variable.

Can I export a variable to the environment from a bash script without sourcing it?

I don't think this can be done but I found a workaround using alias. It will only work when you place your script in your scripts directory, otherwise your alias will have an invalid name. The only point to the work around is to be able to have a function inside a file with the same name and not have to bother sourcing it before using it. Add the following code to ~/.bashrc:

alias myFunction='unalias myFunction && . myFunction && myFunction "$@"'

You can now call myFunction without sourcing it first.

How to urlencode data for curl command?

Here's the node version:

uriencode() {
  node -p "encodeURIComponent('${1//\'/\\\'}')"
}

How to set a parameter in a HttpServletRequest?

You can't, not using the standard API. HttpServletRequest represent a request received by the server, and so adding new parameters is not a valid option (as far as the API is concerned).

You could in principle implement a subclass of HttpServletRequestWrapper which wraps the original request, and intercepts the getParameter() methods, and pass the wrapped request on when you forward.

If you go this route, you should use a Filter to replace your HttpServletRequest with a HttpServletRequestWrapper:

public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
    if (servletRequest instanceof HttpServletRequest) {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        // Check wether the current request needs to be able to support the body to be read multiple times
        if (MULTI_READ_HTTP_METHODS.contains(request.getMethod())) {
            // Override current HttpServletRequest with custom implementation
            filterChain.doFilter(new HttpServletRequestWrapper(request), servletResponse);
            return;
        }
    }
    filterChain.doFilter(servletRequest, servletResponse);
}

Android Studio with Google Play Services

In my case google-play-services_lib are integrate as module (External Libs) for Google map & GCM in my project.

Now, these time require to implement Google Places Autocomplete API but problem is that's code are new and my libs are old so some class not found:

following these steps...

1> Update Google play service into SDK Manager

2> select new .jar file of google play service (Sdk/extras/google/google_play_services/libproject/google-play-services_lib/libs) replace with old one

i got success...!!!

Cannot install signed apk to device manually, got error "App not installed"

The same thing happened to me, as long as I generated my apk from Build> Build APK. I could install and un-install the apk as many times as they were without any problem, but instead if I generated the Build> Generate Signed APK, when I passed the apk to the phone and try to install it, it only allowed me one occasion, the same one that came out the following message:

enter image description here

until then everything was fine if I selected "INSTALL IN ANY WAY", but what happened if I uninstalled the app and wanted to reinstall it (a possible scenario), the following happened:

enter image description here

so I solved the problem by disabling play protect, which I achieved (within Google Play)> Menu> Play Protect> Search for security threats (disable).

enter image description here

enter image description here

Calling functions in a DLL from C++

Can also export functions from dll and import from the exe, it is more tricky at first but in the end is much easier than calling LoadLibrary/GetProcAddress. See MSDN.

When creating the project with the VS wizard there's a check box in the dll that let you export functions.

Then, in the exe application you only have to #include a header from the dll with the proper definitions, and add the dll project as a dependency to the exe application.

Check this other question if you want to investigate this point further Exporting functions from a DLL with dllexport.

Cloning an Object in Node.js

Possibility 1

Low-frills deep copy:

var obj2 = JSON.parse(JSON.stringify(obj1));

Possibility 2 (deprecated)

Attention: This solution is now marked as deprecated in the documentation of Node.js:

The util._extend() method was never intended to be used outside of internal Node.js modules. The community found and used it anyway.

It is deprecated and should not be used in new code. JavaScript comes with very similar built-in functionality through Object.assign().

Original answer::

For a shallow copy, use Node's built-in util._extend() function.

var extend = require('util')._extend;

var obj1 = {x: 5, y:5};
var obj2 = extend({}, obj1);
obj2.x = 6;
console.log(obj1.x); // still logs 5

Source code of Node's _extend function is in here: https://github.com/joyent/node/blob/master/lib/util.js

exports._extend = function(origin, add) {
  // Don't do anything if add isn't an object
  if (!add || typeof add !== 'object') return origin;

  var keys = Object.keys(add);
  var i = keys.length;
  while (i--) {
    origin[keys[i]] = add[keys[i]];
  }
  return origin;
};

JPA Native Query select and cast object

Please refer JPA : How to convert a native query result set to POJO class collection

For Postgres 9.4,

List<String> list = em.createNativeQuery("select cast(row_to_json(u) as text) from myschema.USER_ u WHERE ID = ?")
                   .setParameter(1, id).getResultList();

User map = new ObjectMapper().readValue(list.get(0), User.class);

Recursively look for files with a specific extension

Without using find:

du -a $directory | awk '{print $2}' | grep '\.in$'

How to upload multiple files using PHP, jQuery and AJAX

My solution

  • Assuming that form id = "my_form_id"
  • It detects the form method and form action from HTML

jQuery code

$('#my_form_id').on('submit', function(e) {
    e.preventDefault();
    var formData = new FormData($(this)[0]);
    var msg_error = 'An error has occured. Please try again later.';
    var msg_timeout = 'The server is not responding';
    var message = '';
    var form = $('#my_form_id');
    $.ajax({
        data: formData,
        async: false,
        cache: false,
        processData: false,
        contentType: false,
        url: form.attr('action'),
        type: form.attr('method'),
        error: function(xhr, status, error) {
            if (status==="timeout") {
                alert(msg_timeout);
            } else {
                alert(msg_error);
            }
        },
        success: function(response) {
            alert(response);
        },
        timeout: 7000
    });
});

Disabling buttons on react native

To disable Text you have to set the opacity:0 in Text style like this:

<TouchableOpacity style={{opacity:0}}>
  <Text>I'm disabled</Text>
</TouchableOpacity>

Trim spaces from end of a NSString

A simple solution to only trim one end instead of both ends in Objective-C:

@implementation NSString (category)

/// trims the characters at the end
- (NSString *)stringByTrimmingSuffixCharactersInSet:(NSCharacterSet *)characterSet {
    NSUInteger i = self.length;
    while (i > 0 && [characterSet characterIsMember:[self characterAtIndex:i - 1]]) {
        i--;
    }
    return [self substringToIndex:i];
}

@end

And a symmetrical utility for trimming the beginning only:

@implementation NSString (category)

/// trims the characters at the beginning
- (NSString *)stringByTrimmingPrefixCharactersInSet:(NSCharacterSet *)characterSet {
    NSUInteger i = 0;
    while (i < self.length && [characterSet characterIsMember:[self characterAtIndex:i]]) {
        i++;
    }
    return [self substringFromIndex:i];
}

@end

Iterate through 2 dimensional array

These functions should work.

// First, cache your array dimensions so you don't have to
//  access them during each iteration of your for loops.
int rowLength = array.length,       // array width (# of columns)
    colLength = array[0].length;    // array height (# of rows)

//     This is your function:
// Prints array elements row by row
var rowString = "";
for(int x = 0; x < rowLength; x++){     // x is the column's index
    for(int y = 0; y < colLength; y++){ // y is the row's index
        rowString += array[x][y];
    } System.out.println(rowString)
}

//      This is the one you want:
// Prints array elements column by column
var colString = "";
for(int y = 0; y < colLength; y++){      // y is the row's index
    for(int x = 0; x < rowLength; x++){  // x is the column's index
        colString += array[x][y];
    } System.out.println(colString)
}

In the first block, the inner loop iterates over each item in the row before moving to the next column.

In the second block (the one you want), the inner loop iterates over all the columns before moving to the next row.

tl;dr: Essentially, the for() loops in both functions are switched. That's it.

I hope this helps you to understand the logic behind iterating over 2-dimensional arrays.

Also, this works whether you have a string[,] or string[][]

Change the Blank Cells to "NA"

While many options above function well, I found coercion of non-target variables to chr problematic. Using ifelse and grepl within lapply resolves this off-target effect (in limited testing). Using slarky's regular expression in grepl:

set.seed(42)
x1 <- sample(c("a","b"," ", "a a", NA), 10, TRUE)
x2 <- sample(c(rnorm(length(x1),0, 1), NA), length(x1), TRUE)

df <- data.frame(x1, x2, stringsAsFactors = FALSE)

The problem of coercion to character class:

df2 <- lapply(df, function(x) gsub("^$|^ $", NA, x))
lapply(df2, class)

$x1 [1] "character"

$x2 [1] "character"

Resolution with use of ifelse:

df3 <- lapply(df, function(x) ifelse(grepl("^$|^ $", x)==TRUE, NA, x))
lapply(df3, class)

$x1 [1] "character"

$x2 [1] "numeric"

How can I get a list of Git branches, ordered by most recent commit?

I also needed colors, tags and remote references without any duplicates:

for ref in $(git for-each-ref --sort=-committerdate --format="%(refname)" refs/heads/ refs/remotes ); do git log -n1 $ref --pretty=format:"%Cgreen%cr%Creset %C(yellow)%d%Creset %C(bold blue)<%an>%Creset%n" | cat ; done | awk '! a[$0]++'

Because quoting can be hard, here is the alias for Bash:

alias glist='for ref in $(git for-each-ref --sort=-committerdate --format="%(refname)" refs/heads/ refs/remotes ); do git log -n1 $ref --pretty=format:"%Cgreen%cr%Creset %C(yellow)%d%Creset %C(bold blue)<%an>%Creset%n" | cat ; done | awk '"'! a["'$0'"]++'"

Is it possible to select the last n items with nth-child?

Because of the definition of the semantics of nth-child, I don't see how this is possible without including the length of the list of elements involved. The point of the semantics is to allow segregation of a bunch of child elements into repeating groups (edit - thanks BoltClock) or into a first part of some fixed length, followed by "the rest". You sort-of want the opposite of that, which is what nth-last-child gives you.

data.map is not a function

Objects, {} in JavaScript does not have the method .map(). It's only for Arrays, [].

So in order for your code to work change data.map() to data.products.map() since products is an array which you can iterate upon.

Insert Unicode character into JavaScript

Although @ruakh gave a good answer, I will add some alternatives for completeness:

You could in fact use even var Omega = '&#937;' in JavaScript, but only if your JavaScript code is:

  • inside an event attribute, as in onclick="var Omega = '&#937'; alert(Omega)" or
  • in a script element inside an XHTML (or XHTML + XML) document served with an XML content type.

In these cases, the code will be first (before getting passed to the JavaScript interpreter) be parsed by an HTML parser so that character references like &#937; are recognized. The restrictions make this an impractical approach in most cases.

You can also enter the O character as such, as in var Omega = 'O', but then the character encoding must allow that, the encoding must be properly declared, and you need software that let you enter such characters. This is a clean solution and quite feasible if you use UTF-8 encoding for everything and are prepared to deal with the issues created by it. Source code will be readable, and reading it, you immediately see the character itself, instead of code notations. On the other hand, it may cause surprises if other people start working with your code.

Using the \u notation, as in var Omega = '\u03A9', works independently of character encoding, and it is in practice almost universal. It can however be as such used only up to U+FFFF, i.e. up to \uffff, but most characters that most people ever heard of fall into that area. (If you need “higher” characters, you need to use either surrogate pairs or one of the two approaches above.)

You can also construct a character using the String.fromCharCode() method, passing as a parameter the Unicode number, in decimal as in var Omega = String.fromCharCode(937) or in hexadecimal as in var Omega = String.fromCharCode(0x3A9). This works up to U+FFFF. This approach can be used even when you have the Unicode number in a variable.

Django - taking values from POST request

Read about request objects that your views receive: https://docs.djangoproject.com/en/dev/ref/request-response/#httprequest-objects

Also your hidden field needs a reliable name and then a value:

<input type="hidden" name="title" value="{{ source.title }}">

Then in a view:

request.POST.get("title", "")

What's a redirect URI? how does it apply to iOS app for OAuth2.0?

Take a look at OAuth 2.0 playground.You will get an overview of the protocol.It is basically an environment(like any app) that shows you the steps involved in the protocol.

https://developers.google.com/oauthplayground/

Can I target all <H> tags with a single selector?

You could .class all the headings in Your document if You would like to target them with a single selector, as follows,

<h1 class="heading">...heading text...</h1>
<h2 class="heading">...heading text...</h2>

and in the css

.heading{
    color: #Dad;
    background-color: #DadDad;
}

I am not saying this is always best practice, but it can be useful, and for targeting syntax, easier in many ways,

so if You give all h1 through h6 the same .heading class in the html, then You can modify them for any html docs that utilize that css sheet.

upside, more global control versus "section div article h1, etc{}",

downside, instead of calling all the selectors in on place in the css, You will have much more typing in the html, yet I find that having a class in the html to target all headings can be beneficial, just be careful of precedence in the css, because conflicts could arise from

How to compile and run a C/C++ program on the Android system

You can compile your C programs with an ARM cross-compiler:

arm-linux-gnueabi-gcc -static -march=armv7-a test.c -o test

Then you can push your compiled binary file to somewhere (don't push it in to the SD card):

adb push test /data/local/tmp/test

How to disable phone number linking in Mobile Safari?

Same problem in Sencha Touch app solved with meta tag (<meta name="format-detection" content="telephone=no">) in index.html of app.

In Swift how to call method with parameters on GCD main thread?

Here's the nicer (IMO) Swifty/Cocoa style syntax to achieve the same result as the other answers:

NSOperationQueue.mainQueue().addOperationWithBlock({
    // Your code here
})

Or you could grab the popular Async Swift library for even less code and more functionality:

Async.main {
    // Your code here
}

Resource files not found from JUnit test cases

Make 'maven.test.skip' as false in pom file, while building project test reource will come under test-classes.

<maven.test.skip>false</maven.test.skip>

Android changing Floating Action Button color

I got the same problem and its all snatching my hair. Thanks for this https://stackoverflow.com/a/35697105/5228412

What we can do..

 favourite_fab.setImageDrawable(ContextCompat.getDrawable(getBaseContext(), R.drawable.favourite_selected));

it works fine for me and wish for others who'll reach here.

adb devices command not working

restarting the adb server as root worked for me. see:

derek@zoe:~/Downloads$ adb sideload angler-ota-mtc20f-5a1e93e9.zip 
loading: 'angler-ota-mtc20f-5a1e93e9.zip'
error: insufficient permissions for device
derek@zoe:~/Downloads$ adb devices
List of devices attached
XXXXXXXXXXXXXXXX    no permissions

derek@zoe:~/Downloads$ adb kill-server
derek@zoe:~/Downloads$ sudo adb start-server
* daemon not running. starting it now on port 5037 *
* daemon started successfully *
derek@zoe:~/Downloads$ adb devices
List of devices attached
XXXXXXXXXXXXXXXX    sideload

Build not visible in itunes connect

Well, in my case I uploaded a build with updated version. like 1.1.0 Build 1.1.0, then I reverted back to 1.0.0 build 1.0.5 and the same build was visible under the 1.0.0 header dropdown.

Hope it helps someone.

How to enable scrolling of content inside a modal?

.modal-body {
    max-height: 80vh;
    overflow-y: scroll;
}

it's works for me

Angular.js directive dynamic templateURL

I have an example about this.

<!DOCTYPE html>
<html ng-app="app">

  <head>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
  </head>

  <body>
    <div class="container-fluid body-content" ng-controller="formView">
        <div class="row">
            <div class="col-md-12">
                <h4>Register Form</h4>
                <form class="form-horizontal" ng-submit="" name="f" novalidate>
                    <div ng-repeat="item in elements" class="form-group">
                        <label>{{item.Label}}</label>
                        <element type="{{item.Type}}" model="item"></element>
                    </div>
                    <input ng-show="f.$valid" type="submit" id="submit" value="Submit" class="" />
                </form>
            </div>
        </div>
    </div>
    <script src="https://code.jquery.com/jquery-1.10.2.min.js"></script>
    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
    <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.2/angular.min.js"></script>
    <script src="app.js"></script>
  </body>

</html>

angular.module('app', [])
    .controller('formView', function ($scope) {
        $scope.elements = [{
            "Id":1,
            "Type":"textbox",
            "FormId":24,
            "Label":"Name",
            "PlaceHolder":"Place Holder Text",
            "Max":20,
            "Required":false,
            "Options":null,
            "SelectedOption":null
          },
          {
            "Id":2,
            "Type":"textarea",
            "FormId":24,
            "Label":"AD2",
            "PlaceHolder":"Place Holder Text",
            "Max":20,
            "Required":true,
            "Options":null,
            "SelectedOption":null
        }];
    })
    .directive('element', function () {
        return {
            restrict: 'E',
            link: function (scope, element, attrs) {
                scope.contentUrl = attrs.type + '.html';
                attrs.$observe("ver", function (v) {
                    scope.contentUrl = v + '.html';
                });
            },
            template: '<div ng-include="contentUrl"></div>'
        }
    })

Change the spacing of tick marks on the axis of a plot?

I have a data set with Time as the x-axis, and Intensity as y-axis. I'd need to first delete all the default axes except the axes' labels with:

plot(Time,Intensity,axes=F)

Then I rebuild the plot's elements with:

box() # create a wrap around the points plotted
axis(labels=NA,side=1,tck=-0.015,at=c(seq(from=0,to=1000,by=100))) # labels = NA prevents the creation of the numbers and tick marks, tck is how long the tick mark is.
axis(labels=NA,side=2,tck=-0.015)
axis(lwd=0,side=1,line=-0.4,at=c(seq(from=0,to=1000,by=100))) # lwd option sets the tick mark to 0 length because tck already takes care of the mark
axis(lwd=0,line=-0.4,side=2,las=1) # las changes the direction of the number labels to horizontal instead of vertical.

So, at = c(...) specifies the collection of positions to put the tick marks. Here I'd like to put the marks at 0, 100, 200,..., 1000. seq(from =...,to =...,by =...) gives me the choice of limits and the increments.

Convert list or numpy array of single element to float in python

np.asscalar(a) is deprecated since NumPy v1.16, use a.item() instead.

For example:

a = np.array([[0.6813]])
print(a.item())

gives:

0.6813

Cannot send a content-body with this verb-type

Because you didn't specify the Header.

I've added an extended example:

var request = (HttpWebRequest)WebRequest.Create(strServer + strURL.Split('&')[1].ToString());

Header(ref request, p_Method);

And the method Header:

private void Header(ref HttpWebRequest p_request, string p_Method)
{
    p_request.ContentType = "application/x-www-form-urlencoded";
    p_request.Method = p_Method;
    p_request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows CE)";
    p_request.Host = strServer.Split('/')[2].ToString();
    p_request.Accept = "*/*";
    if (String.IsNullOrEmpty(strURLReferer))
    {
        p_request.Referer = strServer;
    }
    else
    {
        p_request.Referer = strURLReferer;
    }
    p_request.Headers.Add("Accept-Language", "en-us\r\n");
    p_request.Headers.Add("UA-CPU", "x86 \r\n");
    p_request.Headers.Add("Cache-Control", "no-cache\r\n");
    p_request.KeepAlive = true;
}

How to count TRUE values in a logical vector

Another option which hasn't been mentioned is to use which:

length(which(z))

Just to actually provide some context on the "which is faster question", it's always easiest just to test yourself. I made the vector much larger for comparison:

z <- sample(c(TRUE,FALSE),1000000,rep=TRUE)
system.time(sum(z))
   user  system elapsed 
   0.03    0.00    0.03
system.time(length(z[z==TRUE]))
   user  system elapsed 
   0.75    0.07    0.83 
system.time(length(which(z)))
   user  system elapsed 
   1.34    0.28    1.64 
system.time(table(z)["TRUE"])
   user  system elapsed 
  10.62    0.52   11.19 

So clearly using sum is the best approach in this case. You may also want to check for NA values as Marek suggested.

Just to add a note regarding NA values and the which function:

> which(c(T, F, NA, NULL, T, F))
[1] 1 4
> which(!c(T, F, NA, NULL, T, F))
[1] 2 5

Note that which only checks for logical TRUE, so it essentially ignores non-logical values.

Turn Pandas Multi-Index into column

The reset_index() is a pandas DataFrame method that will transfer index values into the DataFrame as columns. The default setting for the parameter is drop=False (which will keep the index values as columns).

All you have to do add .reset_index(inplace=True) after the name of the DataFrame:

df.reset_index(inplace=True)  

Guid is all 0's (zeros)?

Use the static method Guid.NewGuid() instead of calling the default constructor.

var responseObject = proxy.CallService(new RequestObject
{
    Data = "misc. data",
    Guid = Guid.NewGuid()
});

How can I build XML in C#?

For simple cases, I would also suggest looking at XmlOutput a fluent interface for building Xml.

XmlOutput is great for simple Xml creation with readable and maintainable code, while generating valid Xml. The orginal post has some great examples.

How do I disable a href link in JavaScript?

you can deactivate all links in a page with this style class:

a {
    pointer-events:none;
}

now of course the trick is deactivate the links only when you need to, this is how to do it:

use an empty A class, like this:

a {}

then when you want to deactivate the links, do this:

    GetStyleClass('a').pointerEvents = "none"

    function GetStyleClass(className)
    {
       for (var i=0; i< document.styleSheets.length; i++) {
          var styleSheet = document.styleSheets[i]

          var rules = styleSheet.cssRules || styleSheet.rules

          for (var j=0; j<rules.length; j++) {
             var rule = rules[j]

             if (rule.selectorText === className) {
                return(rule.style)
             }
          }
       }

       return 0
    }

NOTE: CSS rule names are transformed to lower case in some browsers, and this code is case sensitive, so better use lower case class names for this

to reactivate links:

GetStyleClass('a').pointerEvents = ""

check this page http://caniuse.com/pointer-events for information about browser compatibility

i think this is the best way to do it, but sadly IE, like always, will not allow it :) i'm posting this anyway, because i think this contains information that can be useful, and because some projects use a know browser, like when you are using web views on mobile devices.

if you just want to deactivate ONE link (i only realize THAT was the question), i would use a function that manualy sets the url of the current page, or not, based on that condition. (like the solution you accepted)

this question was a LOT easier than i thought :)

Remove characters from a string

Using replace() with regular expressions is the most flexible/powerful. It's also the only way to globally replace every instance of a search pattern in JavaScript. The non-regex variant of replace() will only replace the first instance.

For example:

var str = "foo gar gaz";

// returns: "foo bar gaz"
str.replace('g', 'b');

// returns: "foo bar baz"
str = str.replace(/g/gi, 'b');

In the latter example, the trailing /gi indicates case-insensitivity and global replacement (meaning that not just the first instance should be replaced), which is what you typically want when you're replacing in strings.

To remove characters, use an empty string as the replacement:

var str = "foo bar baz";

// returns: "foo r z"
str.replace(/ba/gi, '');

How to combine multiple conditions to subset a data-frame using "OR"?

my.data.frame <- subset(data , V1 > 2 | V2 < 4)

An alternative solution that mimics the behavior of this function and would be more appropriate for inclusion within a function body:

new.data <- data[ which( data$V1 > 2 | data$V2 < 4) , ]

Some people criticize the use of which as not needed, but it does prevent the NA values from throwing back unwanted results. The equivalent (.i.e not returning NA-rows for any NA's in V1 or V2) to the two options demonstrated above without the which would be:

 new.data <- data[ !is.na(data$V1 | data$V2) & ( data$V1 > 2 | data$V2 < 4)  , ]

Note: I want to thank the anonymous contributor that attempted to fix the error in the code immediately above, a fix that got rejected by the moderators. There was actually an additional error that I noticed when I was correcting the first one. The conditional clause that checks for NA values needs to be first if it is to be handled as I intended, since ...

> NA & 1
[1] NA
> 0 & NA
[1] FALSE

Order of arguments may matter when using '&".

Get type name without full namespace

typeof(T).Name // class name, no namespace
typeof(T).FullName // namespace and class name
typeof(T).Namespace // namespace, no class name

Delete cookie by name?

I'm not really sure if that was the situation with Roundcube version from May '12, but for current one the answer is that you can't delete roundcube_sessauth cookie from JavaScript, as it is marked as HttpOnly. And this means it's not accessible from JS client side code and can be removed only by server side script or by direct user action (via some browser mechanics like integrated debugger or some plugin).

What is the optimal way to compare dates in Microsoft SQL server?

You could add a calculated column that includes only the date without the time. Between the two options, I'd go with the BETWEEN operator because it's 'cleaner' to me and should make better use of indexes. Comparing execution plans would seem to indicate that BETWEEN would be faster; however, in actual testing they performed the same.

Introducing FOREIGN KEY constraint may cause cycles or multiple cascade paths - why?

In .NET Core I changed the onDelete option to ReferencialAction.NoAction

         constraints: table =>
            {
                table.PrimaryKey("PK_Schedule", x => x.Id);
                table.ForeignKey(
                    name: "FK_Schedule_Teams_HomeId",
                    column: x => x.HomeId,
                    principalTable: "Teams",
                    principalColumn: "Id",
                    onDelete: ReferentialAction.NoAction);
                table.ForeignKey(
                    name: "FK_Schedule_Teams_VisitorId",
                    column: x => x.VisitorId,
                    principalTable: "Teams",
                    principalColumn: "Id",
                    onDelete: ReferentialAction.NoAction);
            });

Check if multiple strings exist in another string

The regex module recommended in python docs, supports this

words = {'he', 'or', 'low'}
p = regex.compile(r"\L<name>", name=words)
m = p.findall('helloworld')
print(m)

output:

['he', 'low', 'or']

Some details on implementation: link

How to send data with angularjs $http.delete() request?

$http.delete method doesn't accept request body. You can try this workaround :

$http( angular.merge({}, config || {}, {
    method  : 'delete',
    url     : _url,
    data    : _data
}));

where in config you can pass config data like headers etc.

HRESULT: 0x80040154 (REGDB_E_CLASSNOTREG))

This could also be an issue of building the code using a 64 bit configuration. You can try to select x86 as the build platform which can solve this issue. To do this right-click the solution and select Configuration Manager From there you can change the Platform of the project using the 32-bit .dll to x86

Storing query results into a variable and modifying it inside a Stored Procedure

Or you can use one SQL-command instead of create and call stored procedure

INSERT INTO [order_cart](orId,caId)
OUTPUT inserted.*
SELECT
   (SELECT MAX(orId) FROM [order]) as orId,
   (SELECT MAX(caId) FROM [cart]) as caId;

What are some good Python ORM solutions?

There is no conceivable way that the unused features in Django will give a performance penalty. Might just come in handy if you ever decide to upscale the project.

difference between primary key and unique key

Primary Key:

  • There can only be one primary key in a table
  • In some DBMS it cannot be NULL - e.g. MySQL adds NOT NULL
  • Primary Key is a unique key identifier of the record

Unique Key:

  • Can be more than one unique key in one table
  • Unique key can have NULL values
  • It can be a candidate key
  • Unique key can be NULL ; multiple rows can have NULL values and therefore may not be considered "unique"

How can I set selected option selected in vue.js 2?

<select v-model="challan.warehouse_id">
<option value="">Select Warehouse</option>
<option v-for="warehouse in warehouses" v-bind:value="warehouse.id"  >
   {{ warehouse.name }}
</option>

Here "challan.warehouse_id" come from "challan" object you get from:

editChallan: function() {
    let that = this;
    axios.post('/api/challan_list/get_challan_data', {
    challan_id: that.challan_id
 })
 .then(function (response) {
    that.challan = response.data;
 })
 .catch(function (error) {
    that.errors = error;
  }); 
 }

Reversing a string in C

Try this:

reverse_string(NULL);
reverse_string("");

PowerShell Remoting giving "Access is Denied" error

Running the command prompt or Powershell ISE as an administrator fixed this for me.

How can I rebuild indexes and update stats in MySQL innoDB?

For basic cleanup and re-analyzing you can run "OPTIMIZE TABLE ...", it will compact out the overhead in the indexes and run ANALYZE TABLE too, but it's not going to re-sort them and make them as small & efficient as they could be.

https://dev.mysql.com/doc/refman/8.0/en/optimize-table.html

However, if you want the indexes completely rebuilt for best performance, you can:

  1. drop / re-add indexes (obviously)
  2. dump / reload the table
  3. ALTER TABLE and "change" using the same storage engine
  4. REPAIR TABLE (only works for MyISAM, ARCHIVE, and CSV)

https://dev.mysql.com/doc/refman/8.0/en/rebuilding-tables.html

If you do an ALTER TABLE on a field (that is part of an index) and change its type, then it will also fully rebuild the related index(es).

Push origin master error on new repository

I just encountered this problem, and it seemed to be caused by my not adding a custom commit message above the default commit message (I figured, why write "initial commit", when it clearly says that very same thing in the Git-generated text below it).

The problem resolved when I removed the .git directory, re-initialized the project directory for Git, re-added the GitHub remote, added all files to the new stage, committed with a personal message above the auto-generated message, and pushed to origin/master.

HTTP response code for POST when resource already exists

I don't think you should do this.

The POST is, as you know, to modify the collection and it's used to CREATE a new item. So, if you send the id (I think it's not a good idea), you should modify the collection, i.e., modify the item, but it's confusing.

Use it to add an item, without id. It's the best practice.

If you want to capture an UNIQUE constraint (not the id) you can response 409, as you can do in PUT requests. But not the ID.

c# open a new form then close the current form?

The problem beings with that line:

Application.Run(new Form1()); Which probably can be found in your program.cs file.

This line indicates that form1 is to handle the messages loop - in other words form1 is responsible to keep executing your application - the application will be closed when form1 is closed.

There are several ways to handle this, but all of them in one way or another will not close form1.
(Unless we change project type to something other than windows forms application)

The one I think is easiest to your situation is to create 3 forms:

  • form1 - will remain invisible and act as a manager, you can assign it to handle a tray icon if you want.

  • form2 - will have the button, which when clicked will close form2 and will open form3

  • form3 - will have the role of the other form that need to be opened.

And here is a sample code to accomplish that:
(I also added an example to close the app from 3rd form)

static class Program
{
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run(new Form1()); //set the only message pump to form1.
    }
}


public partial class Form1 : Form
{
    public static Form1 Form1Instance;

    public Form1()
    {
        //Everyone eveywhere in the app should know me as Form1.Form1Instance
        Form1Instance = this;

        //Make sure I am kept hidden
        WindowState = FormWindowState.Minimized;
        ShowInTaskbar = false;
        Visible = false;

        InitializeComponent();

        //Open a managed form - the one the user sees..
        var form2 = new Form2();
        form2.Show();
    }

}

public partial class Form2 : Form
{
    public Form2()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        var form3 = new Form3(); //create an instance of form 3
        Hide();             //hide me (form2)
        form3.Show();       //show form3
        Close();            //close me (form2), since form1 is the message loop - no problem.
    }
}

public partial class Form3 : Form
{
    public Form3()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        Form1.Form1Instance.Close(); //the user want to exit the app - let's close form1.
    }
}


Note: working with panels or loading user-controls dynamically is more academic and preferable as industry production standards - but it seems to me you just trying to reason with how things work - for that purpose this example is better.

And now that the principles are understood let's try it with just two forms:

  • The first form will take the role of the manager just like in the previous example but will also present the first screen - so it will not be closed just hidden.

  • The second form will take the role of showing the next screen and by clicking a button will close the application.


    public partial class Form1 : Form
    {
        public static Form1 Form1Instance;

        public Form1()
        {
            //Everyone eveywhere in the app show know me as Form1.Form1Instance
            Form1Instance = this;
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            //Make sure I am kept hidden
            WindowState = FormWindowState.Minimized;
            ShowInTaskbar = false;
            Visible = false;

            //Open another form 
            var form2 = new Form2
            {
                //since we open it from a minimezed window - it will not be focused unless we put it as TopMost.
                TopMost = true
            };
            form2.Show();
            //now that that it is topmost and shown - we want to set its behavior to be normal window again.
            form2.TopMost = false; 
        }
    }

    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Form1.Form1Instance.Close();
        }
    }

If you alter the previous example - delete form3 from the project.

Good Luck.

How to UPSERT (MERGE, INSERT ... ON DUPLICATE UPDATE) in PostgreSQL?

9.5 and newer:

PostgreSQL 9.5 and newer support INSERT ... ON CONFLICT (key) DO UPDATE (and ON CONFLICT (key) DO NOTHING), i.e. upsert.

Comparison with ON DUPLICATE KEY UPDATE.

Quick explanation.

For usage see the manual - specifically the conflict_action clause in the syntax diagram, and the explanatory text.

Unlike the solutions for 9.4 and older that are given below, this feature works with multiple conflicting rows and it doesn't require exclusive locking or a retry loop.

The commit adding the feature is here and the discussion around its development is here.


If you're on 9.5 and don't need to be backward-compatible you can stop reading now.


9.4 and older:

PostgreSQL doesn't have any built-in UPSERT (or MERGE) facility, and doing it efficiently in the face of concurrent use is very difficult.

This article discusses the problem in useful detail.

In general you must choose between two options:

  • Individual insert/update operations in a retry loop; or
  • Locking the table and doing batch merge

Individual row retry loop

Using individual row upserts in a retry loop is the reasonable option if you want many connections concurrently trying to perform inserts.

The PostgreSQL documentation contains a useful procedure that'll let you do this in a loop inside the database. It guards against lost updates and insert races, unlike most naive solutions. It will only work in READ COMMITTED mode and is only safe if it's the only thing you do in the transaction, though. The function won't work correctly if triggers or secondary unique keys cause unique violations.

This strategy is very inefficient. Whenever practical you should queue up work and do a bulk upsert as described below instead.

Many attempted solutions to this problem fail to consider rollbacks, so they result in incomplete updates. Two transactions race with each other; one of them successfully INSERTs; the other gets a duplicate key error and does an UPDATE instead. The UPDATE blocks waiting for the INSERT to rollback or commit. When it rolls back, the UPDATE condition re-check matches zero rows, so even though the UPDATE commits it hasn't actually done the upsert you expected. You have to check the result row counts and re-try where necessary.

Some attempted solutions also fail to consider SELECT races. If you try the obvious and simple:

-- THIS IS WRONG. DO NOT COPY IT. It's an EXAMPLE.

BEGIN;

UPDATE testtable
SET somedata = 'blah'
WHERE id = 2;

-- Remember, this is WRONG. Do NOT COPY IT.

INSERT INTO testtable (id, somedata)
SELECT 2, 'blah'
WHERE NOT EXISTS (SELECT 1 FROM testtable WHERE testtable.id = 2);

COMMIT;

then when two run at once there are several failure modes. One is the already discussed issue with an update re-check. Another is where both UPDATE at the same time, matching zero rows and continuing. Then they both do the EXISTS test, which happens before the INSERT. Both get zero rows, so both do the INSERT. One fails with a duplicate key error.

This is why you need a re-try loop. You might think that you can prevent duplicate key errors or lost updates with clever SQL, but you can't. You need to check row counts or handle duplicate key errors (depending on the chosen approach) and re-try.

Please don't roll your own solution for this. Like with message queuing, it's probably wrong.

Bulk upsert with lock

Sometimes you want to do a bulk upsert, where you have a new data set that you want to merge into an older existing data set. This is vastly more efficient than individual row upserts and should be preferred whenever practical.

In this case, you typically follow the following process:

  • CREATE a TEMPORARY table

  • COPY or bulk-insert the new data into the temp table

  • LOCK the target table IN EXCLUSIVE MODE. This permits other transactions to SELECT, but not make any changes to the table.

  • Do an UPDATE ... FROM of existing records using the values in the temp table;

  • Do an INSERT of rows that don't already exist in the target table;

  • COMMIT, releasing the lock.

For example, for the example given in the question, using multi-valued INSERT to populate the temp table:

BEGIN;

CREATE TEMPORARY TABLE newvals(id integer, somedata text);

INSERT INTO newvals(id, somedata) VALUES (2, 'Joe'), (3, 'Alan');

LOCK TABLE testtable IN EXCLUSIVE MODE;

UPDATE testtable
SET somedata = newvals.somedata
FROM newvals
WHERE newvals.id = testtable.id;

INSERT INTO testtable
SELECT newvals.id, newvals.somedata
FROM newvals
LEFT OUTER JOIN testtable ON (testtable.id = newvals.id)
WHERE testtable.id IS NULL;

COMMIT;

Related reading

What about MERGE?

SQL-standard MERGE actually has poorly defined concurrency semantics and is not suitable for upserting without locking a table first.

It's a really useful OLAP statement for data merging, but it's not actually a useful solution for concurrency-safe upsert. There's lots of advice to people using other DBMSes to use MERGE for upserts, but it's actually wrong.

Other DBs:

How to pass a user / password in ansible command

you can use --extra-vars like this:

$ ansible all --inventory=10.0.1.2, -m ping \
    --extra-vars "ansible_user=root ansible_password=yourpassword"

If you're authenticating to a Linux host that's joined to a Microsoft Active Directory domain, this command line works.

ansible --module-name ping --extra-vars 'ansible_user=domain\user ansible_password=PASSWORD' --inventory 10.10.6.184, all

What are ABAP and SAP?

Attempt to provide simplified explanation:

SAP

  • Firstly it is a product.
  • Owner company, derives its name with the product name "SAP"
  • It is a management system (i.e. referred as ERP). Which means, this is a tool used for "managing the system" (domain specific - finance etc.).

Now, that SAP has created an environment around SAP. In order to operate in SAP environment (i.e. for customisations etc.), language-abstraction was required. Here comes ABAP.

ABAP

  • It is a language (high level), which is used in the SAP environment for customisations or new feature implementations.
  • It is high-level, because, it is known only in SAP environment.

Therefore, any customisation on the basic version of SAP given to some customer of SAP would require ABAP usage, otherwise, just delivered SAP is good enough for usage (i.e. no ABAP required).

Now is another term HANA.

HANA

  • This is an in-memory RDBMS.
  • Another tool/product by SAP, you would say, and its prime focus is to facilitate "analytics".
  • The way, this is designed, gives high compression (column-wise storage) and hence is majorly used for "READ" operations, which is why it is associated with "analysis".

SAP and HANA together abstracts the underlying complexity of database-access queries and UI (developed in java), together, to make the user experience good for the management system (used majorly in analytics, and so that the main focus stays in analytics). This very specific tool/product, is said as "technology", as it has an environment of its own (terminologies etc.). ABAP facilitates further development of the SAP-ERP.

The underlying development is in C, C++ (and ABAP) for SAP.

Using BufferedReader.readLine() in a while loop properly

You can use a structure like the following:

 while ((line = bufferedReader.readLine()) != null) {
            System.out.println(line);
        }

Format SQL in SQL Server Management Studio

There is a special trick I discovered by accident.

  1. Select the query you wish to format.
  2. Ctrl+Shift+Q (This will open your query in the query designer)
  3. Then just go OK Voila! Query designer will format your query for you. Caveat is that you can only do this for statements and not procedural code, but its better than nothing.

Laravel: Get base url

You can use the URL facade which lets you do calls to the URL generator

So you can do:

URL::to('/');

You can also use the application container:

$app->make('url')->to('/');
$app['url']->to('/');
App::make('url')->to('/');

Or inject the UrlGenerator:

<?php
namespace Vendor\Your\Class\Namespace;

use Illuminate\Routing\UrlGenerator;

class Classname
{
    protected $url;

    public function __construct(UrlGenerator $url)
    {
        $this->url = $url;
    }

    public function methodName()
    {
        $this->url->to('/');
    }
}

Double precision floating values in Python?

Here is my solution. I first create random numbers with random.uniform, format them in to string with double precision and then convert them back to float. You can adjust the precision by changing '.2f' to '.3f' etc..

import random
from decimal import Decimal

GndSpeedHigh = float(format(Decimal(random.uniform(5, 25)), '.2f'))
GndSpeedLow = float(format(Decimal(random.uniform(2, GndSpeedHigh)), '.2f'))
GndSpeedMean = float(Decimal(format(GndSpeedHigh + GndSpeedLow) / 2, '.2f')))
print(GndSpeedMean)

Getting Git to work with a proxy server - fails with "Request timed out"

There's something I noticed and want to share here:

git config --global http.proxy http://<proxy address>:<port number>

The method above will not work for SSH URLs (i.e., [email protected]:<user name>/<project name>.git):

git clone [email protected]:<user name>/<project name>.git // will not use the http proxy

And things will not change if we set SSH over the HTTPS port (https://help.github.com/en/articles/using-ssh-over-the-https-port) because it only changes the port (22 by default) the SSH connection connects to.

Generate class from database table

slightly modified from top reply:

declare @TableName sysname = 'HistoricCommand'

declare @Result varchar(max) = '[System.Data.Linq.Mapping.Table(Name = "' + @TableName + '")]
public class Dbo' + @TableName + '
{'

select @Result = @Result + '
    [System.Data.Linq.Mapping.Column(Name = "' + t.ColumnName + '", IsPrimaryKey = ' + pkk.ISPK + ')]
    public ' + ColumnType + NullableSign + ' ' + t.ColumnName + ' { get; set; }
'
from
(
    select 
        replace(col.name, ' ', '_') ColumnName,
        column_id ColumnId,
        case typ.name 
            when 'bigint' then 'long'
            when 'binary' then 'byte[]'
            when 'bit' then 'bool'
            when 'char' then 'string'
            when 'date' then 'DateTime'
            when 'datetime' then 'DateTime'
            when 'datetime2' then 'DateTime'
            when 'datetimeoffset' then 'DateTimeOffset'
            when 'decimal' then 'decimal'
            when 'float' then 'float'
            when 'image' then 'byte[]'
            when 'int' then 'int'
            when 'money' then 'decimal'
            when 'nchar' then 'string'
            when 'ntext' then 'string'
            when 'numeric' then 'decimal'
            when 'nvarchar' then 'string'
            when 'real' then 'double'
            when 'smalldatetime' then 'DateTime'
            when 'smallint' then 'short'
            when 'smallmoney' then 'decimal'
            when 'text' then 'string'
            when 'time' then 'TimeSpan'
            when 'timestamp' then 'DateTime'
            when 'tinyint' then 'byte'
            when 'uniqueidentifier' then 'Guid'
            when 'varbinary' then 'byte[]'
            when 'varchar' then 'string'
            else 'UNKNOWN_' + typ.name
        end ColumnType,
        case 
            when col.is_nullable = 1 and typ.name in ('bigint', 'bit', 'date', 'datetime', 'datetime2', 'datetimeoffset', 'decimal', 'float', 'int', 'money', 'numeric', 'real', 'smalldatetime', 'smallint', 'smallmoney', 'time', 'tinyint', 'uniqueidentifier') 
            then '?' 
            else '' 
        end NullableSign
    from sys.columns col
        join sys.types typ on
            col.system_type_id = typ.system_type_id AND col.user_type_id = typ.user_type_id         
    where object_id = object_id(@TableName) 
) t, 
(
                SELECT c.name  AS 'ColumnName', CASE WHEN dd.pk IS NULL THEN 'false' ELSE 'true' END ISPK           
                FROM        sys.columns c
                    JOIN    sys.tables  t   ON c.object_id = t.object_id    
                    LEFT JOIN (SELECT   K.COLUMN_NAME , C.CONSTRAINT_TYPE as pk  
                        FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS K 
                            LEFT JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS AS C
                        ON K.TABLE_NAME = C.TABLE_NAME
                            AND K.CONSTRAINT_NAME = C.CONSTRAINT_NAME
                            AND K.CONSTRAINT_CATALOG = C.CONSTRAINT_CATALOG
                            AND K.CONSTRAINT_SCHEMA = C.CONSTRAINT_SCHEMA            
                        WHERE K.TABLE_NAME = @TableName) as dd
                     ON dd.COLUMN_NAME = c.name
                 WHERE       t.name = @TableName            
            ) pkk
where pkk.ColumnName = t.ColumnName
order by ColumnId

set @Result = @Result  + '
}'

print @Result

which makes output needed for full LINQ in C# declaration

[System.Data.Linq.Mapping.Table(Name = "HistoricCommand")]
public class DboHistoricCommand
{
    [System.Data.Linq.Mapping.Column(Name = "HistoricCommandId", IsPrimaryKey = true)]
    public int HistoricCommandId { get; set; }

    [System.Data.Linq.Mapping.Column(Name = "PHCloudSoftwareInstanceId", IsPrimaryKey = true)]
    public int PHCloudSoftwareInstanceId { get; set; }

    [System.Data.Linq.Mapping.Column(Name = "CommandType", IsPrimaryKey = false)]
    public int CommandType { get; set; }

    [System.Data.Linq.Mapping.Column(Name = "InitiatedDateTime", IsPrimaryKey = false)]
    public DateTime InitiatedDateTime { get; set; }

    [System.Data.Linq.Mapping.Column(Name = "CompletedDateTime", IsPrimaryKey = false)]
    public DateTime CompletedDateTime { get; set; }

    [System.Data.Linq.Mapping.Column(Name = "WasSuccessful", IsPrimaryKey = false)]
    public bool WasSuccessful { get; set; }

    [System.Data.Linq.Mapping.Column(Name = "Message", IsPrimaryKey = false)]
    public string Message { get; set; }

    [System.Data.Linq.Mapping.Column(Name = "ResponseData", IsPrimaryKey = false)]
    public string ResponseData { get; set; }

    [System.Data.Linq.Mapping.Column(Name = "Message_orig", IsPrimaryKey = false)]
    public string Message_orig { get; set; }

    [System.Data.Linq.Mapping.Column(Name = "Message_XX", IsPrimaryKey = false)]
    public string Message_XX { get; set; }

}

How do I remove the height style from a DIV using jQuery?

$('div#someDiv').removeAttr("height");

Can I use wget to check , but not download

If you are in a directory where only root have access to write in system. Then you can directly use wget www.example.com/wget-test using a standard user account. So it will hit the url but because of having no write permission file won't be saved.. This method is working fine for me as i am using this method for a cronjob. Thanks.

sthx

toBe(true) vs toBeTruthy() vs toBeTrue()

What I do when I wonder something like the question asked here is go to the source.

toBe()

expect().toBe() is defined as:

function toBe() {
  return {
    compare: function(actual, expected) {
      return {
        pass: actual === expected
      };
    }
  };
}

It performs its test with === which means that when used as expect(foo).toBe(true), it will pass only if foo actually has the value true. Truthy values won't make the test pass.

toBeTruthy()

expect().toBeTruthy() is defined as:

function toBeTruthy() {
  return {
    compare: function(actual) {
      return {
        pass: !!actual
      };
    }
  };
}

Type coercion

A value is truthy if the coercion of this value to a boolean yields the value true. The operation !! tests for truthiness by coercing the value passed to expect to a boolean. Note that contrarily to what the currently accepted answer implies, == true is not a correct test for truthiness. You'll get funny things like

> "hello" == true
false
> "" == true
false
> [] == true
false
> [1, 2, 3] == true
false

Whereas using !! yields:

> !!"hello"
true
> !!""
false
> !![1, 2, 3]
true
> !![] 
true

(Yes, empty or not, an array is truthy.)

toBeTrue()

expect().toBeTrue() is part of Jasmine-Matchers (which is registered on npm as jasmine-expect after a later project registered jasmine-matchers first).

expect().toBeTrue() is defined as:

function toBeTrue(actual) {
  return actual === true ||
    is(actual, 'Boolean') &&
    actual.valueOf();
}

The difference with expect().toBeTrue() and expect().toBe(true) is that expect().toBeTrue() tests whether it is dealing with a Boolean object. expect(new Boolean(true)).toBe(true) would fail whereas expect(new Boolean(true)).toBeTrue() would pass. This is because of this funny thing:

> new Boolean(true) === true
false
> new Boolean(true) === false
false

At least it is truthy:

> !!new Boolean(true)
true

Which is best suited for use with elem.isDisplayed()?

Ultimately Protractor hands off this request to Selenium. The documentation states that the value produced by .isDisplayed() is a promise that resolves to a boolean. I would take it at face value and use .toBeTrue() or .toBe(true). If I found a case where the implementation returns truthy/falsy values, I would file a bug report.

Eclipse C++: Symbol 'std' could not be resolved

The problem you are reporting seems to me caused by the following:

  1. you are trying to compile C code and the source file has .cpp extension
  2. you are trying to compile C++ code and the source file has .c extension

In such situation Eclipse cannot recognize the proper compiler to use.

How to scroll HTML page to given anchor?

Great solution by jAndy, but the smooth scroll seems to be having issues working in firefox.

Writing it this way works in Firefox as well.

(function($) {
    $(document).ready(function() {
         $('html, body').animate({
           'scrollTop':   $('#anchorName2').offset().top
         }, 2000);
    });
})(jQuery);

Performing user authentication in Java EE / JSF using j_security_check

I suppose you want form based authentication using deployment descriptors and j_security_check.

You can also do this in JSF by just using the same predefinied field names j_username and j_password as demonstrated in the tutorial.

E.g.

<form action="j_security_check" method="post">
    <h:outputLabel for="j_username" value="Username" />
    <h:inputText id="j_username" />
    <br />
    <h:outputLabel for="j_password" value="Password" />
    <h:inputSecret id="j_password" />
    <br />
    <h:commandButton value="Login" />
</form>

You could do lazy loading in the User getter to check if the User is already logged in and if not, then check if the Principal is present in the request and if so, then get the User associated with j_username.

package com.stackoverflow.q2206911;

import java.io.IOException;
import java.security.Principal;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;
import javax.faces.context.FacesContext;

@ManagedBean
@SessionScoped
public class Auth {

    private User user; // The JPA entity.

    @EJB
    private UserService userService;

    public User getUser() {
        if (user == null) {
            Principal principal = FacesContext.getCurrentInstance().getExternalContext().getUserPrincipal();
            if (principal != null) {
                user = userService.find(principal.getName()); // Find User by j_username.
            }
        }
        return user;
    }

}

The User is obviously accessible in JSF EL by #{auth.user}.

To logout do a HttpServletRequest#logout() (and set User to null!). You can get a handle of the HttpServletRequest in JSF by ExternalContext#getRequest(). You can also just invalidate the session altogether.

public String logout() {
    FacesContext.getCurrentInstance().getExternalContext().invalidateSession();
    return "login?faces-redirect=true";
}

For the remnant (defining users, roles and constraints in deployment descriptor and realm), just follow the Java EE 6 tutorial and the servletcontainer documentation the usual way.


Update: you can also use the new Servlet 3.0 HttpServletRequest#login() to do a programmatic login instead of using j_security_check which may not per-se be reachable by a dispatcher in some servletcontainers. In this case you can use a fullworthy JSF form and a bean with username and password properties and a login method which look like this:

<h:form>
    <h:outputLabel for="username" value="Username" />
    <h:inputText id="username" value="#{auth.username}" required="true" />
    <h:message for="username" />
    <br />
    <h:outputLabel for="password" value="Password" />
    <h:inputSecret id="password" value="#{auth.password}" required="true" />
    <h:message for="password" />
    <br />
    <h:commandButton value="Login" action="#{auth.login}" />
    <h:messages globalOnly="true" />
</h:form>

And this view scoped managed bean which also remembers the initially requested page:

@ManagedBean
@ViewScoped
public class Auth {

    private String username;
    private String password;
    private String originalURL;

    @PostConstruct
    public void init() {
        ExternalContext externalContext = FacesContext.getCurrentInstance().getExternalContext();
        originalURL = (String) externalContext.getRequestMap().get(RequestDispatcher.FORWARD_REQUEST_URI);

        if (originalURL == null) {
            originalURL = externalContext.getRequestContextPath() + "/home.xhtml";
        } else {
            String originalQuery = (String) externalContext.getRequestMap().get(RequestDispatcher.FORWARD_QUERY_STRING);

            if (originalQuery != null) {
                originalURL += "?" + originalQuery;
            }
        }
    }

    @EJB
    private UserService userService;

    public void login() throws IOException {
        FacesContext context = FacesContext.getCurrentInstance();
        ExternalContext externalContext = context.getExternalContext();
        HttpServletRequest request = (HttpServletRequest) externalContext.getRequest();

        try {
            request.login(username, password);
            User user = userService.find(username, password);
            externalContext.getSessionMap().put("user", user);
            externalContext.redirect(originalURL);
        } catch (ServletException e) {
            // Handle unknown username/password in request.login().
            context.addMessage(null, new FacesMessage("Unknown login"));
        }
    }

    public void logout() throws IOException {
        ExternalContext externalContext = FacesContext.getCurrentInstance().getExternalContext();
        externalContext.invalidateSession();
        externalContext.redirect(externalContext.getRequestContextPath() + "/login.xhtml");
    }

    // Getters/setters for username and password.
}

This way the User is accessible in JSF EL by #{user}.

Disable LESS-CSS Overwriting calc()

The solutions of Fabricio works just fine.

A very common usecase of calc is add 100% width and adding some margin around the element.

One can do so with:

@someMarginVariable: 15px;

margin: @someMarginVariable;
width: calc(~"100% - "@someMarginVariable*2);
width: -moz-calc(~"100% - "@someMarginVariable*2);
width: -webkit-calc(~"100% - "@someMarginVariable*2);
width: -o-calc(~"100% - "@someMarginVariable*2);

Or can use a mixin like:

.fullWidthMinusMarginPaddingMixin(@marginSize,@paddingSize) {
  @minusValue: (@marginSize+@paddingSize)*2;
  padding: @paddingSize;
  margin: @marginSize;
  width: calc(~"100% - "@minusValue);
  width: -moz-calc(~"100% - "@minusValue);
  width: -webkit-calc(~"100% - "@minusValue);
  width: -o-calc(~"100% - "@minusValue);
}

Internal Error 500 Apache, but nothing in the logs?

The answers by @eric-leschinski is correct.

But there is another case if your Server API is FPM/FastCGI (Default on Centos 8 or you can check use phpinfo() function)

In this case:

  1. Run phpinfo() in a php file;
  2. Looking for Loaded Configuration File param to see where is config file for your PHP.
  3. Edit config file like @eric-leschinski 's answer.
  4. Check Server API param. If your server only use apache handle API -> restart apache. If your server use php-fpm you must restart php-fpm service

    systemctl restart php-fpm

    Check the log file in php-fpm log folder. eg /var/log/php-fpm/www-error.log

Loop through a comma-separated shell variable

Here's my pure bash solution that doesn't change IFS, and can take in a custom regex delimiter.

loop_custom_delimited() {
    local list=$1
    local delimiter=$2
    local item
    if [[ $delimiter != ' ' ]]; then
        list=$(echo $list | sed 's/ /'`echo -e "\010"`'/g' | sed -E "s/$delimiter/ /g")
    fi
    for item in $list; do
        item=$(echo $item | sed 's/'`echo -e "\010"`'/ /g')
        echo "$item"
    done
}

How do I access previous promise results in a .then() chain?

Solution:

You can put intermediate values in scope in any later 'then' function explicitly, by using 'bind'. It is a nice solution that doesn't require changing how Promises work, and only requires a line or two of code to propagate the values just like errors are already propagated.

Here is a complete example:

// Get info asynchronously from a server
function pGetServerInfo()
    {
    // then value: "server info"
    } // pGetServerInfo

// Write into a file asynchronously
function pWriteFile(path,string)
    {
    // no then value
    } // pWriteFile

// The heart of the solution: Write formatted info into a log file asynchronously,
// using the pGetServerInfo and pWriteFile operations
function pLogInfo(localInfo)
    {
    var scope={localInfo:localInfo}; // Create an explicit scope object
    var thenFunc=p2.bind(scope); // Create a temporary function with this scope
    return (pGetServerInfo().then(thenFunc)); // Do the next 'then' in the chain
    } // pLogInfo

// Scope of this 'then' function is {localInfo:localInfo}
function p2(serverInfo)
    {
    // Do the final 'then' in the chain: Writes "local info, server info"
    return pWriteFile('log',this.localInfo+','+serverInfo);
    } // p2

This solution can be invoked as follows:

pLogInfo("local info").then().catch(err);

(Note: a more complex and complete version of this solution has been tested, but not this example version, so it could have a bug.)

How can I alias a default import in JavaScript?

defaultMember already is an alias - it doesn't need to be the name of the exported function/thing. Just do

import alias from 'my-module';

Alternatively you can do

import {default as alias} from 'my-module';

but that's rather esoteric.

invalid use of non-static data member

In C++, nested classes are not connected to any instance of the outer class. If you want bar to access non-static members of foo, then bar needs to have access to an instance of foo. Maybe something like:

class bar {
  public:
    int getA(foo & f ) {return foo.a;}
};

Or maybe

class bar {
  private:
    foo & f;

  public:
    bar(foo & g)
    : f(g)
    {
    }

    int getA() { return f.a; }
};

In any case, you need to explicitly make sure you have access to an instance of foo.

Save PHP array to MySQL?

Just use the serialize PHP function:

<?php
$myArray = array('1', '2');
$seralizedArray = serialize($myArray);
?>

However, if you are using simple arrays like that you might as well use implode and explode.Use a blank array instead of new.

2 ways for "ClearContents" on VBA Excel, but 1 work fine. Why?

It is because you haven't qualified Cells(1, 1) with a worksheet object, and the same holds true for Cells(10, 2). For the code to work, it should look something like this:

Dim ws As Worksheet

Set ws = Sheets("SheetName")
Range(ws.Cells(1, 1), ws.Cells(10, 2)).ClearContents

Alternately:

With Sheets("SheetName")
    Range(.Cells(1, 1), .Cells(10, 2)).ClearContents
End With

EDIT: The Range object will inherit the worksheet from the Cells objects when the code is run from a standard module or userform. If you are running the code from a worksheet code module, you will need to qualify Range also, like so:

ws.Range(ws.Cells(1, 1), ws.Cells(10, 2)).ClearContents

or

With Sheets("SheetName")
    .Range(.Cells(1, 1), .Cells(10, 2)).ClearContents
End With

What is the best way to search the Long datatype within an Oracle database?

First convert LONG type column to CLOB type then use LIKE condition, for example:

CREATE TABLE tbl_clob AS
   SELECT to_lob(long_col) lob_col FROM tbl_long;

SELECT * FROM tbl_clob WHERE lob_col LIKE '%form%';

Moment.js get day name from date

var mydate = "2017-06-28T00:00:00";
var weekDayName =  moment(mydate).format('ddd');
console.log(weekDayName);

Result: Wed

var mydate = "2017-06-28T00:00:00";
var weekDayName =  moment(mydate).format('dddd');
console.log(weekDayName);

Result: Wednesday

Getting the count of unique values in a column in bash

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

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

fileA.txt

z    z    a
a    b    c
w    d    e

fileB.txt

t    r    e
z    d    a
a    g    c

fileC.txt

z    r    a
v    d    c
a    m    c

Result:

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

Print a string as hex bytes?

With f-string:

"".join(f"{ord(c):x}" for c in "Hello")

How to set the text/value/content of an `Entry` widget using a button in tkinter

If you use a "text variable" tk.StringVar(), you can just set() that.

No need to use the Entry delete and insert. Moreover, those functions don't work when the Entry is disabled or readonly! The text variable method, however, does work under those conditions as well.

import Tkinter as tk

...

entryText = tk.StringVar()
entry = tk.Entry( master, textvariable=entryText )
entryText.set( "Hello World" )

Resolving LNK4098: defaultlib 'MSVCRT' conflicts with

There are 4 versions of the CRT link libraries present in vc\lib:

  • libcmt.lib: static CRT link library for a release build (/MT)
  • libcmtd.lib: static CRT link library for a debug build (/MTd)
  • msvcrt.lib: import library for the release DLL version of the CRT (/MD)
  • msvcrtd.lib: import library for the debug DLL version of the CRT (/MDd)

Look at the linker options, Project + Properties, Linker, Command Line. Note how these libraries are not mentioned here. The linker automatically figures out what /M switch was used by the compiler and which .lib should be linked through a #pragma comment directive. Kinda important, you'd get horrible link errors and hard to diagnose runtime errors if there was a mismatch between the /M option and the .lib you link with.

You'll see the error message you quoted when the linker is told both to link to msvcrt.lib and libcmt.lib. Which will happen if you link code that was compiled with /MT with code that was linked with /MD. There can be only one version of the CRT.

/NODEFAULTLIB tells the linker to ignore the #pragma comment directive that was generated from the /MT compiled code. This might work, although a slew of other linker errors is not uncommon. Things like errno, which is a extern int in the static CRT version but macro-ed to a function in the DLL version. Many others like that.

Well, fix this problem the Right Way, find the .obj or .lib file that you are linking that was compiled with the wrong /M option. If you have no clue then you could find it by grepping the .obj/.lib files for "/MT"

Btw: the Windows executables (like version.dll) have their own CRT version to get their job done. It is located in c:\windows\system32, you cannot reliably use it for your own programs, its CRT headers are not available anywhere. The CRT DLL used by your program has a different name (like msvcrt90.dll).

"SyntaxError: Unexpected token < in JSON at position 0"

This error occurs when you define the response as application/json and you are getting a HTML as a response. Basically, this happened when you are writing server side script for specific url with a response of JSON but the error format is in HTML.

SQL Server default character encoding

SELECT DATABASEPROPERTYEX('DBName', 'Collation') SQLCollation;

Where DBName is your database name.

Handling the TAB character in Java

Yes the tab character is one character. You can match it in java with "\t".

Docker how to change repository name or rename image?

As a shorthand you can run:

docker tag d58 myname/server:latest

Where d58 represents the first 3 characters of the IMAGE ID,in this case, that's all you need.

Finally, you can remove the old image as follows:

docker rmi server

How can I make a .NET Windows Forms application that only runs in the System Tray?

"System tray" application is just a regular win forms application, only difference is that it creates a icon in windows system tray area. In order to create sys.tray icon use NotifyIcon component , you can find it in Toolbox(Common controls), and modify it's properties: Icon, tool tip. Also it enables you to handle mouse click and double click messages.

And One more thing , in order to achieve look and feels or standard tray app. add followinf lines on your main form show event:

private void MainForm_Shown(object sender, EventArgs e)
{
    WindowState = FormWindowState.Minimized;
    Hide();
} 

HTML Best Practices: Should I use &rsquo; or the special keyboard shortcut?

If your text will be consumed by non-browsers then it's safer to type the character with the keyboard-combo option shift right bracket because &rsquo; will not be transformed into an apostrophe by a regular XML or JSON parser. (e.g. if you are serving this content to native Android/iOS apps).

What is the difference between .py and .pyc files?

Python compiles the .py and saves files as .pyc so it can reference them in subsequent invocations.

There's no harm in deleting them, but they will save compilation time if you're doing lots of processing.

How to create a custom navigation drawer in android

The easier solution for me was:

Considerations:

  • This solution requires autogenerated Navigation Drawer Activity provided by Android Studio.
  • Classes DrawerItem, CustomDrawerAdapter and layout custom_drawer_item.xml were taken from this tutorial.

1. Create this class for wrap the custom drawer item:

public class DrawerItem {

  String ItemName;
  int imgResID;

  public DrawerItem(String itemName, int imgResID) {
        super();
        ItemName = itemName;
        this.imgResID = imgResID;
  }

  public String getItemName() {
        return ItemName;
  }
  public void setItemName(String itemName) {
        ItemName = itemName;
  }
  public int getImgResID() {
        return imgResID;
  }
  public void setImgResID(int imgResID) {
        this.imgResID = imgResID;
  }
}

2. Create custom layout (custom_drawer_item.xml) for your drawer items:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

<LinearLayout
    android:id="@+id/itemLayout"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:orientation="vertical"
    android:layout_marginTop="0dp"
    android:background="?android:attr/activatedBackgroundIndicator">

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:minHeight="55dp">

        <ImageView
            android:id="@+id/drawer_icon"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"/>

        <TextView
            android:id="@+id/drawer_itemName"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textAppearance="?android:attr/textAppearanceLarge"/>
    </LinearLayout>

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:layout_marginBottom="1dp"
        android:layout_marginTop="1dp"
        android:layout_marginLeft="10dp"
        android:layout_marginRight="10dp"
        android:background="#DADADC">
    </View>
</LinearLayout>
</RelativeLayout>

3. Create your custom adapter:

import java.util.List;
import android.app.Activity;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

public class CustomDrawerAdapter extends ArrayAdapter<DrawerItem> {

Context context;
List<DrawerItem> drawerItemList;
int layoutResID;

public CustomDrawerAdapter(Context context, int layoutResourceID, List<DrawerItem> listItems) {
    super(context, layoutResourceID, listItems);
    this.context = context;
    this.drawerItemList = listItems;
    this.layoutResID = layoutResourceID;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub

    DrawerItemHolder drawerHolder;
    View view = convertView;

    if (view == null) {
        LayoutInflater inflater = ((Activity) context).getLayoutInflater();
        drawerHolder = new DrawerItemHolder();

        view = inflater.inflate(layoutResID, parent, false);
        drawerHolder.ItemName = (TextView)view.findViewById(R.id.drawer_itemName);
        drawerHolder.icon = (ImageView) view.findViewById(R.id.drawer_icon);

        view.setTag(drawerHolder);

    } else {
        drawerHolder = (DrawerItemHolder) view.getTag();
    }

    DrawerItem dItem = (DrawerItem) this.drawerItemList.get(position);

    drawerHolder.icon.setImageDrawable(view.getResources().getDrawable(
            dItem.getImgResID()));
    drawerHolder.ItemName.setText(dItem.getItemName());

    return view;
}

private static class DrawerItemHolder {
    TextView ItemName;
    ImageView icon;
}
}

4. In autogenerated NavigationDrawerFragment class onCreateView method, replace the autogenerated adapter for this:

ArrayList<DrawerItem> dataList = new ArrayList<DrawerItem>();
dataList.add(new DrawerItem(getString(R.string.title_section1), R.drawable.ic_action_1));
dataList.add(new DrawerItem(getString(R.string.title_section2), R.drawable.ic_action_2));
dataList.add(new DrawerItem(getString(R.string.title_section3), R.drawable.ic_action_3));

mDrawerListView.setAdapter(new CustomDrawerAdapter(
        getActivity(),
        R.layout.custom_drawer_item,
        dataList));

Remember replace R.string.title_sectionN and R.drawable.ic_action_N for your own resources.

How can I show dots ("...") in a span with hidden overflow?

I think you are looking for text-overflow: ellipsis in combination with white-space: nowrap

See some more details here

How to avoid the "Windows Defender SmartScreen prevented an unrecognized app from starting warning"

After clicking on Properties of any installer(.exe) which block your application to install (Windows Defender SmartScreen prevented an unrecognized app ) for that issue i found one solution

  1. Right click on installer(.exe)
  2. Select properties option.
  3. Click on checkbox to check Unblock at the bottom of Properties.

This solution work for Heroku CLI (heroku-x64) installer(.exe)

Maven fails to find local artifact

check if if your artifact Y have packaging set to "jar". If you have defined it as "war" by error or copy paste, it will show this strange "was cached in the local repository, resolution will not be reattempted until the update interval of internal has elapsed or updates are forced". I would expect something like "artifact Y is war, jar type expected".

Split a vector into chunks

This splits into chunks of size ?n/k?+1 or ?n/k? and does not use the O(n log n) sort.

get_chunk_id<-function(n, k){
    r <- n %% k
    s <- n %/% k
    i<-seq_len(n)
    1 + ifelse (i <= r * (s+1), (i-1) %/% (s+1), r + ((i - r * (s+1)-1) %/% s))
}

split(1:10, get_chunk_id(10,3))

How can I debug what is causing a connection refused or a connection time out?

Use a packet analyzer to intercept the packets to/from somewhere.com. Studying those packets should tell you what is going on.

Time-outs or connections refused could mean that the remote host is too busy.

jQuery: find element by text

In jQuery documentation it says:

The matching text can appear directly within the selected element, in any of that element's descendants, or a combination

Therefore it is not enough that you use :contains() selector, you also need to check if the text you search for is the direct content of the element you are targeting for, something like that:

function findElementByText(text) {
    var jSpot = $("b:contains(" + text + ")")
                .filter(function() { return $(this).children().length === 0;})
                .parent();  // because you asked the parent of that element

    return jSpot;
}

jQuery scroll to ID from different page

I've written something that detects if the page contains the anchor that was clicked on, and if not, goes to the normal page, otherwise it scrolls to the specific section:

$('a[href*=\\#]').on('click',function(e) {

    var target = this.hash;
    var $target = $(target);
    console.log(targetname);
    var targetname = target.slice(1, target.length);

    if(document.getElementById(targetname) != null) {
         e.preventDefault();
    }
    $('html, body').stop().animate({
        'scrollTop': $target.offset().top-120 //or the height of your fixed navigation 

    }, 900, 'swing', function () {
        window.location.hash = target;
  });
});

Getting All Variables In Scope

I made a fiddle implementing (essentially) above ideas outlined by iman. Here is how it looks when you mouse over the second ipsum in return ipsum*ipsum - ...

enter image description here

The variables which are in scope are highlighted where they are declared (with different colors for different scopes). The lorem with red border is a shadowed variable (not in scope, but be in scope if the other lorem further down the tree wouldn't be there.)

I'm using esprima library to parse the JavaScript, and estraverse, escodegen, escope (utility libraries on top of esprima.) The 'heavy lifting' is done all by those libraries (the most complex being esprima itself, of course.)

How it works

ast = esprima.parse(sourceString, {range: true, sourceType: 'script'});

makes the abstract syntax tree. Then,

analysis = escope.analyze(ast);

generates a complex data structure encapsulating information about all the scopes in the program. The rest is gathering together the information encoded in that analysis object (and the abstract syntax tree itself), and making an interactive coloring scheme out of it.

So the correct answer is actually not "no", but "yes, but". The "but" being a big one: you basically have to rewrite significant parts of the chrome browser (and it's devtools) in JavaScript. JavaScript is a Turing complete language, so of course that is possible, in principle. What is impossible is doing the whole thing without using the entirety of your source code (as a string) and then doing highly complex stuff with that.

How can I check the system version of Android?

For example, a feature only works for api21 up the following we fix bugs in api21 down

    if(Build.VERSION.SDK_INT >= 21) {
    //only api 21 above
    }else{
   //only api 21 down
    }

Current time in microseconds in java

No, Java doesn't have that ability.

It does have System.nanoTime(), but that just gives an offset from some previously known time. So whilst you can't take the absolute number from this, you can use it to measure nanosecond (or higher) precision.

Note that the JavaDoc says that whilst this provides nanosecond precision, that doesn't mean nanosecond accuracy. So take some suitably large modulus of the return value.

How can I add an image file into json object?

You're only adding the File object to the JSON object. The File object only contains meta information about the file: Path, name and so on.

You must load the image and read the bytes from it. Then put these bytes into the JSON object.

How do I add an existing Solution to GitHub from Visual Studio 2013

OK this worked for me.

  1. Open the solution in Visual Studio 2013
  2. Select File | Add to Source Control
  3. Select the Microsoft Git Provider

That creates a local GIT repository

  1. Surf to GitHub
  2. Create a new repository DO NOT SELECT Initialize this repository with a README

That creates an empty repository with no Master branch

  1. Once created open the repository and copy the URL (it's on the right of the screen in the current version)
  2. Go back to Visual Studio
    • Make sure you have the Microsoft Git Provider selected under Tools/Options/Source Control/Plug-in Selection
  3. Open Team Explorer
  4. Select Home | Unsynced Commits
  5. Enter the GitHub URL into the yellow box (use HTTPS URL, not the default shown SSH one)
  6. Click Publish
  7. Select Home | Changes
  8. Add a Commit comment
  9. Select Commit and Push from the drop down

Your solution is now in GitHub

Run an Ansible task only when the variable contains a specific string

This works for me in Ansible 2.9:

variable1 = www.example.com. 
variable2 = www.example.org. 

when: ".com" in variable1

and for not:

when: not ".com" in variable2

Set selected item of spinner programmatically

You can make a generic method for this kind of work as I do in my UtilityClass which is

public void SetSpinnerSelection(Spinner spinner,String[] array,String text) {
    for(int i=0;i<array.length;i++) {
        if(array[i].equals(text)) {
            spinner.setSelection(i);
        }
    }
}

Cannot install node modules that require compilation on Windows 7 x64/VS2012

Try that - will set it globally:

npm config set msvs_version 2012 --global

Delete many rows from a table using id in Mysql

if you need to keep only a few rows, consider

DELETE FROM tablename WHERE id NOT IN (5,124,221);

This will keep only some records and discard others.

Set today's date as default date in jQuery UI datepicker

$("#date").datepicker.regional[""].dateFormat = 'dd/mm/yy';
$("#date").datepicker("setDate", new Date());

Always work for me

How to refresh table contents in div using jquery/ajax

You can load HTML page partial, in your case is everything inside div#mytable.

setTimeout(function(){
   $( "#mytable" ).load( "your-current-page.html #mytable" );
}, 2000); //refresh every 2 seconds

more information read this http://api.jquery.com/load/

Update Code (if you don't want it auto-refresh)

<button id="refresh-btn">Refresh Table</button>

<script>
$(document).ready(function() {

   function RefreshTable() {
       $( "#mytable" ).load( "your-current-page.html #mytable" );
   }

   $("#refresh-btn").on("click", RefreshTable);

   // OR CAN THIS WAY
   //
   // $("#refresh-btn").on("click", function() {
   //    $( "#mytable" ).load( "your-current-page.html #mytable" );
   // });


});
</script>

How do I remove whitespace from the end of a string in Python?

You can use strip() or split() to control the spaces values as in the following:

words = "   first  second   "

# Remove end spaces
def remove_end_spaces(string):
    return "".join(string.rstrip())


# Remove the first and end spaces
def remove_first_end_spaces(string):
    return "".join(string.rstrip().lstrip())


# Remove all spaces
def remove_all_spaces(string):
    return "".join(string.split())


# Show results
print(words)
print(remove_end_spaces(words))
print(remove_first_end_spaces(words))
print(remove_all_spaces(words))

How to add Android Support Repository to Android Studio?

Android Studio 3

Make sure you have the latest version of Android Studio. The support library is included by default when you create new projects. If you are adding the Support Library to a project that doesn't have it, then you just need to add a single line to your app module's build.gradle file, and then sync gradle.

build.gradle

dependencies {
    ...
    implementation 'com.android.support:appcompat-v7:27.1.1'
} 

It should just be that easy, though there may be some things to note:

  • Android Studio should give you a warning nowadays if the support library needs to be updated. Just update the 27.1.1 numbers that I have here to whatever it tells you to. You can also manually check what the latest revision is if you want to.
  • The implementation keyword replaces compile that was used in Android Studio 2.x. (What's the difference?)
  • There are other support library packages that you may need to include depending on what your app uses (like constraint-layout or recyclerview).
  • Make sure that you have the latest updates for everything in the SDK Manager. Go to Tools > SDK Manager.

Documentation

Find max and second max salary for a employee table MySQL

This is awesome Query to find the nth Maximum: For example: -

  1. You want to find salary 8th row Salary, Just Changed the indexed value to 8.

  2. Suppose you have 100 rows with Salary. Now you want to find Max salary for 90th row. Just changed the Indexed Value to 90.

    set @n:=0;
    select * from (select *, (@n:=@n+1) as indexed from employee order by Salary desc)t where t.indexed = 1;
    

Error Code: 1005. Can't create table '...' (errno: 150)

It happened in my case, because the name of the table being referenced in the constraint declaration wasn't correct (I forgot the upper case in the table name):

ALTER TABLE `Window` ADD CONSTRAINT `Windows_ibfk_1` FOREIGN KEY (`WallId`) REFERENCES `Wall` (`id`) ON DELETE CASCADE ON UPDATE CASCADE;

How to stick table header(thead) on top while scrolling down the table rows with fixed header(navbar) in bootstrap 3?

I faced the same issue and as majority of the answers indicated, you have to apply position: sticky; and top: 0; ( mostly but can vary if there is a navbar which is fixed as well) to 'th' element. These properties do not apply to thead or tr.

One more thing, if it still doesn't work, you have to look for 'overflow' properties of the parent. If any parent component has an overflow set, i.e. overflow: hidden, then position: sticky just doesn't work. Make sure to remove all such parent properties. Chao!

Changing variable names with Python for loops

It looks like you want to use a list instead:

group=[]
for i in range(3):
     group[i]=self.getGroup(selected, header+i)

Why catch and rethrow an exception in C#?

It depends what you are doing in the catch block, and if you are wanting to pass the error on to the calling code or not.

You might say Catch io.FileNotFoundExeption ex and then use an alternative file path or some such, but still throw the error on.

Also doing Throw instead of Throw Ex allows you to keep the full stack trace. Throw ex restarts the stack trace from the throw statement (I hope that makes sense).

Command line .cmd/.bat script, how to get directory of running script

Raymond Chen has a few ideas:

https://devblogs.microsoft.com/oldnewthing/20050128-00/?p=36573

Quoted here in full because MSDN archives tend to be somewhat unreliable:

The easy way is to use the %CD% pseudo-variable. It expands to the current working directory.

set OLDDIR=%CD%
.. do stuff ..
chdir /d %OLDDIR% &rem restore current directory

(Of course, directory save/restore could more easily have been done with pushd/popd, but that's not the point here.)

The %CD% trick is handy even from the command line. For example, I often find myself in a directory where there's a file that I want to operate on but... oh, I need to chdir to some other directory in order to perform that operation.

set _=%CD%\curfile.txt
cd ... some other directory ...
somecommand args %_% args

(I like to use %_% as my scratch environment variable.)

Type SET /? to see the other pseudo-variables provided by the command processor.

Also the comments in the article are well worth scanning for example this one (via the WayBack Machine, since comments are gone from older articles):

http://blogs.msdn.com/oldnewthing/archive/2005/01/28/362565.aspx#362741

This covers the use of %~dp0:

If you want to know where the batch file lives: %~dp0

%0 is the name of the batch file. ~dp gives you the drive and path of the specified argument.

An attempt was made to access a socket in a way forbidden by its access permissions

My situation and solution: I had created and enabled a HyperV ethernet adapter. For some reason, my main windows machine was using the "virtual" ethernet adapter instead of the 'hardware' adapter.

I disabled the virtual ethernet and my network settings to change the network public/privacy settings were revealed.

jQuery duplicate DIV into another DIV

Copy code using clone and appendTo function :

Here is also working example jsfiddle

<!DOCTYPE html>
<html>
<head>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
</head>
<body>
<div id="copy"><a href="http://brightwaay.com">Here</a> </div>
<br/>
<div id="copied"></div>
<script type="text/javascript">
    $(function(){
        $('#copy').clone().appendTo('#copied');
    });
</script>
</body>
</html>

Reloading/refreshing Kendo Grid

If you do not want to have a reference to the grid in the handler, you can use this code:

 $(".k-pager-refresh").trigger('click');

This will refresh the grid, if there is a refresh button. The button can be enabled like so:

[MVC GRID DECLARATION].Pageable(p=> p.Refresh(true))

Clear and refresh jQuery Chosen dropdown list

$("#idofBtn").click(function(){
        $('#idofdropdown').empty(); //remove all child nodes
        var newOption = $('<option value="1">test</option>');
        $('#idofdropdown').append(newOption);
        $('#idofdropdown').trigger("chosen:updated");
    });

How to do a HTTP HEAD request from the windows command line?

On Linux, I often use curl with the --head parameter. It is available for several operating systems, including Windows.

[edit] related to the answer below, gknw.net is currently down as of February 23 2012. Check curl.haxx.se for updated info.

Any way to make plot points in scatterplot more transparent in R?

If you are using the hex codes, you can add two more digits at the end of the code to represent the alpha channel:

E.g. half-transparency red:

plot(1:100, main="Example of Plot With Transparency")
lines(1:100 + sin(1:100*2*pi/(20)), col='#FF000088', lwd=4)
mtext("use `col='#FF000088'` for the lines() function")

example plot of color with transparency

VBA array sort function?

Somewhat related, but I was also looking for a native excel VBA solution since advanced data structures (Dictionaries, etc.) aren't working in my environment. The following implements sorting via a binary tree in VBA:

  • Assumes array is populated one by one
  • Removes duplicates
  • Returns a separated string ("0|2|3|4|9") which can then be split.

I used it for returning a raw sorted enumeration of rows selected for an arbitrarily selected range

Private Enum LeafType: tEMPTY: tTree: tValue: End Enum
Private Left As Variant, Right As Variant, Center As Variant
Private LeftType As LeafType, RightType As LeafType, CenterType As LeafType
Public Sub Add(x As Variant)
    If CenterType = tEMPTY Then
        Center = x
        CenterType = tValue
    ElseIf x > Center Then
        If RightType = tEMPTY Then
            Right = x
            RightType = tValue
        ElseIf RightType = tTree Then
            Right.Add x
        ElseIf x <> Right Then
            curLeaf = Right
            Set Right = New TreeList
            Right.Add curLeaf
            Right.Add x
            RightType = tTree
        End If
    ElseIf x < Center Then
        If LeftType = tEMPTY Then
            Left = x
            LeftType = tValue
        ElseIf LeftType = tTree Then
            Left.Add x
        ElseIf x <> Left Then
            curLeaf = Left
            Set Left = New TreeList
            Left.Add curLeaf
            Left.Add x
            LeftType = tTree
        End If
    End If
End Sub
Public Function GetList$()
    Const sep$ = "|"
    If LeftType = tValue Then
        LeftList$ = Left & sep
    ElseIf LeftType = tTree Then
        LeftList = Left.GetList & sep
    End If
    If RightType = tValue Then
        RightList$ = sep & Right
    ElseIf RightType = tTree Then
        RightList = sep & Right.GetList
    End If
    GetList = LeftList & Center & RightList
End Function

'Sample code
Dim Tree As new TreeList
Tree.Add("0")
Tree.Add("2")
Tree.Add("2")
Tree.Add("-1")
Debug.Print Tree.GetList() 'prints "-1|0|2"
sortedList = Split(Tree.GetList(),"|")

JS map return object

You're very close already, you just need to return the new object that you want. In this case, the same one except with the launches value incremented by 10:

_x000D_
_x000D_
var rockets = [_x000D_
    { country:'Russia', launches:32 },_x000D_
    { country:'US', launches:23 },_x000D_
    { country:'China', launches:16 },_x000D_
    { country:'Europe(ESA)', launches:7 },_x000D_
    { country:'India', launches:4 },_x000D_
    { country:'Japan', launches:3 }_x000D_
];_x000D_
_x000D_
var launchOptimistic = rockets.map(function(elem) {_x000D_
  return {_x000D_
    country: elem.country,_x000D_
    launches: elem.launches+10,_x000D_
  } _x000D_
});_x000D_
_x000D_
console.log(launchOptimistic);
_x000D_
_x000D_
_x000D_

How to get datetime in JavaScript?

Semantically, you're probably looking for the one-liner

new Date().toLocaleString()

which formats the date in the locale of the user.

If you're really looking for a specific way to format dates, I recommend the moment.js library.

Get an image extension from an uploaded file in Laravel

Do something like this:

if($request->hasFile('video')){

    $video=$request->file('video');
    $filename=str_random(20).".".$video->extension(); 
    $path = Storage::putFileAs(
            '/', $video, $filename
     );
    $data['video']=$filename;
 }

Why does Java have an "unreachable statement" compiler error?

There is no definitive reason why unreachable statements must be not be allowed; other languages allow them without problems. For your specific need, this is the usual trick:

if (true) return;

It looks nonsensical, anyone who reads the code will guess that it must have been done deliberately, not a careless mistake of leaving the rest of statements unreachable.

Java has a little bit support for "conditional compilation"

http://java.sun.com/docs/books/jls/third_edition/html/statements.html#14.21

if (false) { x=3; }

does not result in a compile-time error. An optimizing compiler may realize that the statement x=3; will never be executed and may choose to omit the code for that statement from the generated class file, but the statement x=3; is not regarded as "unreachable" in the technical sense specified here.

The rationale for this differing treatment is to allow programmers to define "flag variables" such as:

static final boolean DEBUG = false;

and then write code such as:

if (DEBUG) { x=3; }

The idea is that it should be possible to change the value of DEBUG from false to true or from true to false and then compile the code correctly with no other changes to the program text.

Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

My problem was that I installed mysql successfully and it worked fine.

But one day, the same error occurred.

Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

And no mysql.sock file existed.

This sollution solved my problem and mysql was up and running again:

Log in as root:

sudo su -

Run:

systemctl stop mysqld.service
systemctl start mysqld.service
systemctl enable mysqld.service

Test as root:

mysql -u root -p

mysql should now be up and running.

I hope this can help someone else as well.

What I can do to resolve "1 commit behind master"?

If your branch is behind by master then do:

git checkout master (you are switching your branch to master)
git pull 
git checkout yourBranch (switch back to your branch)
git merge master

After merging it, check if there is a conflict or not.
If there is NO CONFLICT then:

git push

If there is a conflict then fix your file(s), then:

git add yourFile(s)
git commit -m 'updating my branch'
git push

How to get the type of a variable in MATLAB?

class() function is the equivalent of typeof()

You can also use isa() to check if a variable is of a particular type. If you want to be even more specific, you can use ischar(), isfloat(), iscell(), etc.

React JS onClick event handler

This is a non-standard (but not so uncommon) React pattern that doesn't use JSX, instead putting everything inline. Also, it's Coffeescript.

The 'React-way' to do this would be with the component's own state:

(c = console.log.bind console)

mock_items: [
    {
        name: 'item_a'
        uid: shortid()
    }
    {
        name: 'item_b'
        uid: shortid()
    }
    {
        name: 'item_c'
        uid: shortid()
    }
]
getInitialState: ->
    lighted_item: null
render: ->
    div null,
        ul null,
            for item, idx in @mock_items
                uid = item.uid
                li
                    key: uid
                    onClick: do (idx, uid) =>
                        (e) =>
                            # justf to illustrate these are bound in closure by the do lambda,
                            c idx
                            c uid
                            @setState
                                lighted_item: uid
                    style:
                        cursor: 'pointer'
                        background: do (uid) =>
                            c @state.lighted_item
                            c 'and uid', uid
                            if @state.lighted_item is uid then 'magenta' else 'chartreuse'
                        # background: 'chartreuse'
                    item.name

This example works -- I tested it locally. You can check out this example code exactly at my github. Originally the env was only local for my own whiteboard r&d purposes but I posted it to Github for this. It may get written over at some point but you can check out the commit from Sept 8, 2016 to see this.

More generally, if you want to see how this CS/no-JSX pattern for React works, check out some recent work here. It's possible I will have time to fully implement a POC for this app idea, the stack for which includes NodeJS, Primus, Redis, & React.

jQuery - Getting the text value of a table cell in the same row as a clicked element

so you can use parent() to reach to the parent tr and then use find to gather the td with class two

var Something = $(this).parent().find(".two").html();

or

var Something = $(this).parent().parent().find(".two").html();

use as much as parent() what ever the depth of the clicked object according to the tr row

hope this works...

Spring JPA and persistence.xml

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

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

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

In production I configure spring like this:

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

along with the reference in web.xml

For unit testing I do this:

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

Python foreach equivalent

Its also interesting to observe this

To iterate over the indices of a sequence, you can combine range() and len() as follows:

a = ['Mary', 'had', 'a', 'little', 'lamb']
for i in range(len(a)):
  print(i, a[i])

output

0 Mary
1 had
2 a
3 little
4 lamb

Edit#1: Alternate way:

When looping through a sequence, the position index and corresponding value can be retrieved at the same time using the enumerate() function.

for i, v in enumerate(['tic', 'tac', 'toe']):
  print(i, v)

output

0 tic
1 tac
2 toe

Getting the name of a variable as a string

I don't believe this is possible. Consider the following example:

>>> a = []
>>> b = a
>>> id(a)
140031712435664
>>> id(b)
140031712435664

The a and b point to the same object, but the object can't know what variables point to it.

How to convert a huge list-of-vector to a matrix more efficiently?

you can use as.matrix as below:

output <- as.matrix(z)

Priority queue in .Net

here's one i just wrote, maybe it's not as optimized (just uses a sorted dictionary) but simple to understand. you can insert objects of different kinds, so no generic queues.

using System;
using System.Diagnostics;
using System.Collections;
using System.Collections.Generic;

namespace PrioQueue
{
    public class PrioQueue
    {
        int total_size;
        SortedDictionary<int, Queue> storage;

        public PrioQueue ()
        {
            this.storage = new SortedDictionary<int, Queue> ();
            this.total_size = 0;
        }

        public bool IsEmpty ()
        {
            return (total_size == 0);
        }

        public object Dequeue ()
        {
            if (IsEmpty ()) {
                throw new Exception ("Please check that priorityQueue is not empty before dequeing");
            } else
                foreach (Queue q in storage.Values) {
                    // we use a sorted dictionary
                    if (q.Count > 0) {
                        total_size--;
                        return q.Dequeue ();
                    }
                }

                Debug.Assert(false,"not supposed to reach here. problem with changing total_size");

                return null; // not supposed to reach here.
        }

        // same as above, except for peek.

        public object Peek ()
        {
            if (IsEmpty ())
                throw new Exception ("Please check that priorityQueue is not empty before peeking");
            else
                foreach (Queue q in storage.Values) {
                    if (q.Count > 0)
                        return q.Peek ();
                }

                Debug.Assert(false,"not supposed to reach here. problem with changing total_size");

                return null; // not supposed to reach here.
        }

        public object Dequeue (int prio)
        {
            total_size--;
            return storage[prio].Dequeue ();
        }

        public void Enqueue (object item, int prio)
        {
            if (!storage.ContainsKey (prio)) {
                storage.Add (prio, new Queue ());
              }
            storage[prio].Enqueue (item);
            total_size++;

        }
    }
}

How do you kill a Thread in Java?

There is a way how you can do it. But if you had to use it, either you are a bad programmer or you are using a code written by bad programmers. So, you should think about stopping being a bad programmer or stopping using this bad code. This solution is only for situations when THERE IS NO OTHER WAY.

Thread f = <A thread to be stopped>
Method m = Thread.class.getDeclaredMethod( "stop0" , new Class[]{Object.class} );
m.setAccessible( true );
m.invoke( f , new ThreadDeath() );

What's the difference between Html.Label, Html.LabelFor and Html.LabelForModel

I think that the usage of @Html.LabelForModel() should be explained in more detail.

The LabelForModel Method returns an HTML label element and the property name of the property that is represented by the model.

You could refer to the following code:

Code in model:

using System.ComponentModel;

[DisplayName("MyModel")]
public class MyModel
{
    [DisplayName("A property")]
    public string Test { get; set; }
}

Code in view:

@Html.LabelForModel()
<div class="form-group">

    @Html.LabelFor(model => model.Test, new { @class = "control-label col-md-2" })

    <div class="col-md-10">
        @Html.EditorFor(model => model.Test)
        @Html.ValidationMessageFor(model => model.Test)
    </div>
</div>

The output screenshot:

enter image description here

Reference to answer on the asp.net forum