Programs & Examples On #Filenet p8

FileNet P8 is an Enterprise Content Management System produced by IBM. This is a "software to help enterprises manage their content and business processes."

Handling the window closing event with WPF / MVVM Light Toolkit

Here is an answer according to the MVVM-pattern if you don't want to know about the Window (or any of its event) in the ViewModel.

public interface IClosing
    /// <summary>
    /// Executes when window is closing
    /// </summary>
    /// <returns>Whether the windows should be closed by the caller</returns>
    bool OnClosing();

In the ViewModel add the interface and implementation

public bool OnClosing()
    bool close = true;

    //Ask whether to save changes och cancel etc
    //close = false; //If you want to cancel close

    return close;

In the Window I add the Closing event. This code behind doesn't break the MVVM pattern. The View can know about the viewmodel!

void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
    IClosing context = DataContext as IClosing;
    if (context != null)
        e.Cancel = !context.OnClosing();

Map a 2D array onto a 1D array

Example : we want to represent an 2D array of SIZE_X and SIZE_Y size. That means that we will have MAXY consecutive rows of MAXX size. Hence the set function is

void set_array( int x, int y, int val ) { array[ x * SIZE_Y + y ] = val; }

The get would be:

int get_array( int x, int y ) { return array[ x * SIZE_Y + y ]; }

How to make a window always stay on top in .Net?

Set the form's .TopMost property to true.

You probably don't want to leave it this way all the time: set it when your external process starts and put it back when it finishes.

Multiple lines of input in <input type="text" />

You need to use a textarea to get multiline handling.

<textarea name="Text1" cols="40" rows="5"></textarea>

Freeing up a TCP/IP port?

In terminal type :

netstat -anp|grep "port_number"

It will show the port details. Go to last column. It will be in this format . For example :- PID/java

then execute :

kill -9 PID. Worked on Centos5

For MAC:

lsof -n -i :'port-number' | grep LISTEN

Sample Response :

java   4744 (PID)  test  364u  IP0 asdasdasda   0t0  TCP *:port-number (LISTEN)

and then execute :

kill -9 PID 

Worked on Macbook

Creating a copy of an object in C#

You could do:

class myClass : ICloneable
    public String test;
    public object Clone()
        return this.MemberwiseClone();

then you can do

myClass a = new myClass();
myClass b = (myClass)a.Clone();

N.B. MemberwiseClone() Creates a shallow copy of the current System.Object.

Algorithm to detect overlapping periods

I don't believe that the framework itself has this class. Maybe a third-party library...

But why not create a Period value-object class to handle this complexity? That way you can ensure other constraints, like validating start vs end datetimes. Something like:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Whatever.Domain.Timing {
    public class Period {
        public DateTime StartDateTime {get; private set;}
        public DateTime EndDateTime {get; private set;}

        public Period(DateTime StartDateTime, DateTime EndDateTime) {
            if (StartDateTime > EndDateTime)
                throw new InvalidPeriodException("End DateTime Must Be Greater Than Start DateTime!");
            this.StartDateTime = StartDateTime;
            this.EndDateTime = EndDateTime;

        public bool Overlaps(Period anotherPeriod){
            return (this.StartDateTime < anotherPeriod.EndDateTime && anotherPeriod.StartDateTime < this.EndDateTime)

        public TimeSpan GetDuration(){
            return EndDateTime - StartDateTime;


    public class InvalidPeriodException : Exception {
        public InvalidPeriodException(string Message) : base(Message) { }    

That way you will be able to individually compare each period...

Plotting two variables as lines using ggplot2 on the same graph

I am also new to R but trying to understand how ggplot works I think I get another way to do it. I just share probably not as a complete perfect solution but to add some different points of view.

I know ggplot is made to work with dataframes better but maybe it can be also sometimes useful to know that you can directly plot two vectors without using a dataframe.

Loading data. Original date vector length is 100 while var0 and var1 have length 50 so I only plot the available data (first 50 dates).

var0 <- 100 + c(0, cumsum(runif(49, -20, 20)))
var1 <- 150 + c(0, cumsum(runif(49, -10, 10)))
date <- seq(as.Date("2002-01-01"), by="1 month", length.out=50)    


ggplot() + geom_line(aes(x=date,y=var0),color='red') + 
           geom_line(aes(x=date,y=var1),color='blue') + 

enter image description here

However I was not able to add a correct legend using this format. Does anyone know how?

Using the && operator in an if statement

So to make your expression work, changing && for -a will do the trick.

It is correct like this:

 if [ -f $VAR1 ] && [ -f $VAR2 ] && [ -f $VAR3 ]
 then  ....

or like

 if [[ -f $VAR1 && -f $VAR2 && -f $VAR3 ]]
 then  ....

or even

 if [ -f $VAR1 -a -f $VAR2 -a -f $VAR3 ]
 then  ....

You can find further details in this question bash : Multiple Unary operators in if statement and some references given there like What is the difference between test, [ and [[ ?.

Calculating the distance between 2 points

Given points (X1,Y1) and (X2,Y2) then:

dX = X1 - X2;
dY = Y1 - Y2;

if (dX*dX + dY*dY > (5*5))
    //your code

Allow scroll but hide scrollbar

I know this is an oldie but here is a quick way to hide the scroll bar with pure CSS.

Just add

::-webkit-scrollbar {display:none;}

To your id or class of the div you're using the scroll bar with.

Here is a helpful link Custom Scroll Bar in Webkit

Sort array by firstname (alphabetically) in Javascript

Suppose you have an array users. You may use users.sort and pass a function that takes two arguments and compare them (comparator)

It should return

  • something negative if first argument is less than second (should be placed before the second in resulting array)
  • something positive if first argument is greater (should be placed after second one)
  • 0 if those two elements are equal.

In our case if two elements are a and b we want to compare a.firstname and b.firstname


users.sort(function(a, b){
    if(a.firstname < b.firstname) { return -1; }
    if(a.firstname > b.firstname) { return 1; }
    return 0;

This code is going to work with any type.

Note that in "real life"™ you often want to ignore case, correctly sort diacritics, weird symbols like ß, etc when you compare strings, so you may want to use localeCompare. See other answers for clarity.

How to add jQuery in JS file

it is not possible to import js file inside another js file

The way to use jquery inside js is

import the js in the html or whatever view page you are using inside which you are going to include the js file


 <script src="<%=request.getContextPath()%>/js/jquery-1.11.3.js"></script>
 <script src="<%=request.getContextPath()%>/js/default.js"></script>


$('document').ready(function() {
    $('li#user').click(function() {

this will definitely work for you

How to convert a byte to its binary string representation

Sorry i know this is a bit late... But i have a much easier way... To binary string :

//Add 128 to get a value from 0 - 255
String bs = Integer.toBinaryString(data[i]+128);
bs = getCorrectBits(bs, 8);

getCorrectBits method :

private static String getCorrectBits(String bitStr, int max){
    //Create a temp string to add all the zeros
    StringBuilder sb = new StringBuilder();
    for(int i = 0; i < (max - bitStr.length()); i ++){

    return sb.toString()+ bitStr;

Updating GUI (WPF) using a different thread

You may use a delegate to solve this issue. Here is an example that is showing how to update a textBox using diffrent thread

public delegate void UpdateTextCallback(string message);

private void TestThread()
    for (int i = 0; i <= 1000000000; i++)
            new UpdateTextCallback(this.UpdateText),
            new object[] { i.ToString() }
private void UpdateText(string message)
    richTextBox1.AppendText(message + "\n");

private void button1_Click(object sender, RoutedEventArgs e)
   Thread test = new Thread(new ThreadStart(TestThread));

TestThread method is used by thread named test to update textBox

How to redirect all HTTP requests to HTTPS

I found a method to force all pages of my site redirect from http to analog of pages on https that work for me.

RewriteEngine On 
RewriteCond %{HTTP:X-Forwarded-Proto} !https
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI} [R=301,L]

Selenium WebDriver: Wait for complex page with JavaScript to load

Using implicit wait works for me.

driver.Manage().Timeouts().ImplicitWait = TimeSpan.FromSeconds(10);

Refer to this answer Selenium c# Webdriver: Wait Until Element is Present

SQLSTATE[42S22]: Column not found: 1054 Unknown column - Laravel

You don't have a field named user_email in the members table ... as for why, I'm not sure as the code "looks" like it should try to join on different fields

Does the Auth::attempt method perform a join of the schema? Run grep -Rl 'class Auth' /path/to/framework and find where the attempt method is and what it does.

How to change spinner text size and text color?

we can change style of spinner textview set theme for spinner like this:


<style name="mySpinnerItemStyle" parent="@android:style/Widget.Holo.DropDownItem.Spinner">
    <item name="android:textSize">@dimen/_11ssp</item>
    <item name="android:textColor">@color/blue</item>
    <item name=...</item>



if you want to change spinner textview attribute programtically:


val textView = (view.getChildAt(0) as TextView)

How to initialize array to 0 in C?

Global variables and static variables are automatically initialized to zero. If you have simply

char ZEROARRAY[1024];

at global scope it will be all zeros at runtime. But actually there is a shorthand syntax if you had a local array. If an array is partially initialized, elements that are not initialized receive the value 0 of the appropriate type. You could write:

char ZEROARRAY[1024] = {0};

The compiler would fill the unwritten entries with zeros. Alternatively you could use memset to initialize the array at program startup:

memset(ZEROARRAY, 0, 1024);

That would be useful if you had changed it and wanted to reset it back to all zeros.

Function ereg_replace() is deprecated - How to clear this bug?

Here is more information regarding replacing ereg_replace with preg_replace

How do I create a copy of an object in PHP?

The answers are commonly found in Java books.

  1. cloning: If you don't override clone method, the default behavior is shallow copy. If your objects have only primitive member variables, it's totally ok. But in a typeless language with another object as member variables, it's a headache.

  2. serialization/deserialization

$new_object = unserialize(serialize($your_object))

This achieves deep copy with a heavy cost depending on the complexity of the object.

phpmyadmin "Not Found" after install on Apache, Ubuntu

sudo ln -s /etc/phpmyadmin/apache.conf /etc/apache2/conf-available/phpmyadmin.conf

sudo ln -s /usr/share/phpmyadmin /var/www/html/phpmyadmin

sudo service apache2 restart

Run above commands issue will be resolved.

How can I expose more than 1 port with Docker?

if you use docker-compose.ymlfile:

            - 80
            - 6081

You can also specify the host/network port as HOST/NETWORK_PORT:CONTAINER_PORT

        - 81:80
        - 6081:6081

How to change the JDK for a Jenkins job?

For existing jobs you're editing, the JDK drop-down choice may not be available if you've just added a single JDK config in the 'Configure System' Jenkins settings.

However, it is available for new jobs.

Surprisingly, if you add a second JDK config, it becomes available in an existing job too.

This looks to me like a bug (tested in Jenkins ver. 1.629).

See a similar issue raised here: JDK selection is hidden even when a JDK is configured

How can I compare time in SQL Server?

If you're using SQL Server 2008, you can do this:

WHERE CONVERT(time(0), startHour) >= CONVERT(time(0), @startTime)

Here's a full test:

    timeEvent   int      IDENTITY,
    startHour   datetime

INSERT INTO @tbEvents (startHour) SELECT DATEADD(hh, 0, GETDATE())
INSERT INTO @tbEvents (startHour) SELECT DATEADD(hh, 1, GETDATE())
INSERT INTO @tbEvents (startHour) SELECT DATEADD(hh, 2, GETDATE())
INSERT INTO @tbEvents (startHour) SELECT DATEADD(hh, 3, GETDATE())
INSERT INTO @tbEvents (startHour) SELECT DATEADD(hh, 4, GETDATE())
INSERT INTO @tbEvents (startHour) SELECT DATEADD(hh, 5, GETDATE())

--SELECT * FROM @tbEvents

DECLARE @startTime  datetime

SET @startTime = DATEADD(mi, 65, GETDATE())

    CONVERT(time(0), startHour)  AS 'startHour',
    CONVERT(time(0), @startTime) AS '@startTime'
FROM @tbEvents
WHERE CONVERT(time(0), startHour) >= CONVERT(time(0), @startTime)

Set value for particular cell in pandas DataFrame with iloc

For mixed position and index, use .ix. BUT you need to make sure that your index is not of integer, otherwise it will cause confusions.

df.ix[0, 'COL_NAME'] = x


Alternatively, try

df.iloc[0, df.columns.get_loc('COL_NAME')] = x


import pandas as pd
import numpy as np

# your data
# ========================
df = pd.DataFrame(np.random.randn(10, 2), columns=['col1', 'col2'], index=np.random.randint(1,100,10)).sort_index()


      col1    col2
10  1.7641  0.4002
24  0.1440  1.4543
29  0.3131 -0.8541
32  0.9501 -0.1514
33  1.8676 -0.9773
36  0.7610  0.1217
56  1.4941 -0.2052
58  0.9787  2.2409
75 -0.1032  0.4106
76  0.4439  0.3337

# .iloc with get_loc
# ===================================
df.iloc[0, df.columns.get_loc('col2')] = 100


      col1      col2
10  1.7641  100.0000
24  0.1440    1.4543
29  0.3131   -0.8541
32  0.9501   -0.1514
33  1.8676   -0.9773
36  0.7610    0.1217
56  1.4941   -0.2052
58  0.9787    2.2409
75 -0.1032    0.4106
76  0.4439    0.3337

jQuery changing font family and font size

In some browsers, fonts are set explicit for textareas and inputs, so they don’t inherit the fonts from higher elements. So, I think you need to apply the font styles for each textarea and input in the document as well (not just the body).

One idea might be to add clases to the body, then use CSS to style the document accordingly.

better way to drop nan rows in pandas

Use dropna:


You can pass param how to drop if all labels are nan or any of the labels are nan

dat.dropna(how='any')    #to drop if any value in the row has a nan
dat.dropna(how='all')    #to drop if all values in the row are nan

Hope that answers your question!

Edit 1: In case you want to drop rows containing nan values only from particular column(s), as suggested by J. Doe in his answer below, you can use the following:

dat.dropna(subset=[col_list])  # col_list is a list of column names to consider for nan values.

How to generate a random number between a and b in Ruby?



When max is a Range, rand returns a random number where range.member?(number) == true.

How do I parse a YAML file in Ruby?

Maybe I'm missing something, but why try to parse the file? Why not just load the YAML and examine the object(s) that result?

If your sample YAML is in some.yml, then this:

require 'yaml'
thing = YAML.load_file('some.yml')
puts thing.inspect

gives me

{"javascripts"=>[{"fo_global"=>["lazyload-min", "holla-min"]}]}

Setting default value for TypeScript object passed as argument

No, TypeScript doesn't have a natural way of setting defaults for properties of an object defined like that where one has a default and the other does not. You could define a richer structure:

class Name {
    constructor(public first : string, 
        public last: string = "Smith") {


And use that in place of the inline type definition.

function sayName(name: Name) {
    alert(name.first + " " + name.last);

You can't do something like this unfortunately:

function sayName(name : { first: string; last?:string } 
       /* and then assign a default object matching the signature */  
       = { first: null, last: 'Smith' }) {


As it would only set the default if name was undefined.

Add Foreign Key relationship between two Databases

You would need to manage the referential constraint across databases using a Trigger.

Basically you create an insert, update trigger to verify the existence of the Key in the Primary key table. If the key does not exist then revert the insert or update and then handle the exception.


Create Trigger dbo.MyTableTrigger ON dbo.MyTable, After Insert, Update

   If NOT Exists(select PK from OtherDB.dbo.TableName where PK in (Select FK from inserted) BEGIN
      -- Handle the Referential Error Here


Edited: Just to clarify. This is not the best approach with enforcing referential integrity. Ideally you would want both tables in the same db but if that is not possible. Then the above is a potential work around for you.

How can I check if a file exists in Perl?

You can use: if(-e $base_path)

Get IFrame's document, from JavaScript in main document

In case you get a cross-domain error:

If you have control over the content of the iframe - that is, if it is merely loaded in a cross-origin setup such as on Amazon Mechanical Turk - you can circumvent this problem with the <body onload='my_func(my_arg)'> attribute for the inner html.

For example, for the inner html, use the this html parameter (yes - this is defined and it refers to the parent window of the inner body element):

<body onload='changeForm(this)'>

In the inner html :

    function changeForm(window) {
        console.log('inner window loaded: do whatever you want with the inner html');
        window.document.getElementById('mturk_form').style.display = 'none';

Login failed for user 'IIS APPPOOL\ASP.NET v4.0'

I solved this problem using sql as following image.

Right click on db-> properties -> permission -> View Server permission -> and then select IIS APPPOOL\ASP.NET v4.0 and grant permission.


Change user-agent for Selenium web-driver

This is a short solution to change the request UserAgent on the fly.

Change UserAgent of a request with Chrome

from selenium import webdriver
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities

driver = webdriver.Chrome(driver_path)
driver.execute_cdp_cmd('Network.setUserAgentOverride', {"userAgent":"python 2.7", "platform":"Windows"})

then return your useragent:

agent = driver.execute_script("return navigator.userAgent")

Some sources

The source code of from SeleniumHQ ( extends its functionalities through the Chrome Devtools Protocol

def execute_cdp_cmd(self, cmd, cmd_args):
        Execute Chrome Devtools Protocol command and get returned result

We can use the Chrome Devtools Protocol Viewer to list more extended functionalities ( as well as the parameters type to use.

How to convert ASCII code (0-255) to its corresponding character?

    for (int i = 0; i < 256; i++) {
        System.out.println(i + " -> " + (char) i);

    char lowercase = 'f';
    int offset = (int) 'a' - (int) 'A';
    char uppercase = (char) ((int) lowercase - offset);
    System.out.println("The uppercase letter is " + uppercase);

    String numberString = JOptionPane.showInputDialog(null,
            "Enter an ASCII code:",
            "ASCII conversion", JOptionPane.QUESTION_MESSAGE);

    int code = (int) numberString.charAt(0);
    System.out.println("The character for ASCII code "
            + code + " is " + (char) code);

How to implement onBackPressed() in Fragments?

Best solution,


public class BaseActivity extends AppCompatActivity {
    public void onBackPressed() {

        FragmentManager fm = getSupportFragmentManager();
        for (Fragment frag : fm.getFragments()) {
            if (frag == null) {
            if (frag.isVisible()) {
                FragmentManager childFm = frag.getChildFragmentManager();
                if (childFm.getFragments() == null) {
                if (childFm.getBackStackEntryCount() > 0) {
                else {

                    if (fm.getFragments().size() <= 1) {


How to change Label Value using javascript

You're taking name in document.getElementById() Your cb should be txt206451 (ID Attribute) not name attribute.


You can have it by document.getElementsByName()

var cb = document.getElementsByName('field206451')[0]; // First one


var cb = document.getElementById('txt206451');

And for setting values into hidden use document.getElementsByName() like following

var cb = document.getElementById('txt206451');
var label = document.getElementsByName('label206451')[0]; // Get the first one of index
cb.addEventListener('change', function (evt) { // use change here. not neccessarily
    if (this.checked) {
        label.value = 'Thanks'
    } else {
        label.value = '0'
}, false);

Demo Fiddle

Include CSS and Javascript in my django template

First, create staticfiles folder. Inside that folder create css, js, and img folder.

import os

PROJECT_DIR = os.path.dirname(__file__)

    'default': {
         'ENGINE': 'django.db.backends.sqlite3', 
         'NAME': os.path.join(PROJECT_DIR, 'myweblabdev.sqlite'),                        
         'USER': '',
         'PASSWORD': '',
         'HOST': '',                      
         'PORT': '',                     

MEDIA_ROOT = os.path.join(PROJECT_DIR, 'media')

MEDIA_URL = '/media/'

STATIC_ROOT = os.path.join(PROJECT_DIR, 'static')

STATIC_URL = '/static/'

    os.path.join(PROJECT_DIR, 'staticfiles'),


from django.conf.urls import patterns, include, url
from django.conf.urls.static import static
from django.contrib import admin
from django.contrib.staticfiles.urls import staticfiles_urlpatterns
from myweblab import settings


urlpatterns = patterns('',
) + static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)

urlpatterns += staticfiles_urlpatterns()


{% load static %}

<link rel="stylesheet" href="{% static 'css/style.css' %}">

How can I make grep print the lines below and above each matching line?

Use -B, -A or -C option

grep --help
-B, --before-context=NUM  print NUM lines of leading context
-A, --after-context=NUM   print NUM lines of trailing context
-C, --context=NUM         print NUM lines of output context
-NUM                      same as --context=NUM

Typescript import/as vs import/require?

These are mostly equivalent, but import * has some restrictions that import ... = require doesn't.

import * as creates an identifier that is a module object, emphasis on object. According to the ES6 spec, this object is never callable or newable - it only has properties. If you're trying to import a function or class, you should use

import express = require('express');

or (depending on your module loader)

import express from 'express';

Attempting to use import * as express and then invoking express() is always illegal according to the ES6 spec. In some runtime+transpilation environments this might happen to work anyway, but it might break at any point in the future without warning, which will make you sad.

Return index of highest value in an array


$array = array(11 => 14,
               10 => 9,
               12 => 7,
               13 => 7,
               14 => 4,
               15 => 6);

echo array_search(max($array), $array);


array_search() return values:

Returns the key for needle if it is found in the array, FALSE otherwise.

If needle is found in haystack more than once, the first matching key is returned. To return the keys for all matching values, use array_keys() with the optional search_value parameter instead.

javascript: detect scroll end

I found an alternative that works.

None of these answers worked for me (currently testing in FireFox 22.0), and after a lot of research I found, what seems to be, a much cleaner and straight forward solution.

Implemented solution:

function IsScrollbarAtBottom() {
    var documentHeight = $(document).height();
    var scrollDifference = $(window).height() + $(window).scrollTop();
    return (documentHeight == scrollDifference);



filter items in a python dictionary where keys contain a specific string

Jonathon gave you an approach using dict comprehensions in his answer. Here is an approach that deals with your do something part.

If you want to do something with the values of the dictionary, you don't need a dictionary comprehension at all:

I'm using iteritems() since you tagged your question with

results = map(some_function, [(k,v) for k,v in a_dict.iteritems() if 'foo' in k])

Now the result will be in a list with some_function applied to each key/value pair of the dictionary, that has foo in its key.

If you just want to deal with the values and ignore the keys, just change the list comprehension:

results = map(some_function, [v for k,v in a_dict.iteritems() if 'foo' in k])

some_function can be any callable, so a lambda would work as well:

results = map(lambda x: x*2, [v for k,v in a_dict.iteritems() if 'foo' in k])

The inner list is actually not required, as you can pass a generator expression to map as well:

>>> map(lambda a: a[0]*a[1], ((k,v) for k,v in {2:2, 3:2}.iteritems() if k == 2))

How do I get the domain originating the request in express.js?

Recently faced a problem with fetching 'Origin' request header, then I found this question. But pretty confused with the results, req.get('host') is deprecated, that's why giving Undefined. Use,

    // this method can be used to access other request headers like, 'Referer', 'User-Agent' etc.

What is the easiest way to push an element to the beginning of the array?

You can also use array concatenation:

a = [2, 3]
[1] + a
=> [1, 2, 3]

This creates a new array and doesn't modify the original.

How to call getResources() from a class which has no context?

A Context is a handle to the system; it provides services like resolving resources, obtaining access to databases and preferences, and so on. It is an "interface" that allows access to application specific resources and class and information about application environment. Your activities and services also extend Context to they inherit all those methods to access the environment information in which the application is running.

This means you must have to pass context to the specific class if you want to get/modify some specific information about the resources. You can pass context in the constructor like

public classname(Context context, String s1) 

How to create new div dynamically, change it, move it, modify it in every way possible, in JavaScript?

Have you tried JQuery? Vanilla javascript can be tough. Try using this:

$('.container-element').add('<div>Insert Div Content</div>');

.container-element is a JQuery selector that marks the element with the class "container-element" (presumably the parent element in which you want to insert your divs). Then the add() function inserts HTML into the container-element.

.m2 , settings.xml in Ubuntu

As per Where is Maven Installed on Ubuntu it will first create your settings.xml on /usr/share/maven2/, then you can copy to your home folder as jens mentioned

$ cp /usr/share/maven3/conf/settings.xml ~/.m2/settings.xml

How to send email from MySQL 5.1

I would be very concerned about putting the load of sending e-mails on my database server (small though it may be). I might suggest one of these alternatives:

  1. Have application logic detect the need to send an e-mail and send it.
  2. Have a MySQL trigger populate a table that queues up the e-mails to be sent and have a process monitor that table and send the e-mails.

Warning: mysqli_error() expects exactly 1 parameter, 0 given error

At first, the problem is because you did't put any parameter for mysqli_error. I can see that it has been solved based on the post here. Most probably, the next problem is cause by wrong file path for the included file.. .

Are you sure this code

$myConnection = mysqli_connect("$db_host","$db_username","$db_pass","$db_name") or die ("could not connect to mysql");

is in the 'scripts' folder and your main code file is on the same level as the script folder?

Converting a Date object to a calendar object

it's so easy...converting a date to calendar like this:

Calendar cal=Calendar.getInstance();
DateFormat format=new SimpleDateFormat("yyyy/mm/dd");

How do you beta test an iphone app?

Using testflight :

1) create the ipa file by development certificate

2) upload the ipa file on testflight

3) Now, to identify the device to be tested on , add the device id on apple account and refresh your development certificate. Download the updated certificate and upload it on testflight website. Check the device id you are getting.

4) Now email the ipa file to the testers.

5) While downloading the ipa file, if the testers are not getting any warnings, this means the device token + provisioning profile has been verified. So, the testers can now download the ipa file on device and do the testing job...

Finding the number of non-blank columns in an Excel sheet using VBA

Jean-François Corbett's answer is perfect. To be exhaustive I would just like to add that with some restrictons you could also use UsedRange.Columns.Count or UsedRange.Rows.Count.
The problem is that UsedRange is not always updated when deleting rows/columns (at least until you reopen the workbook).

package R does not exist

Just got rid of the error in my project. I had imported a sample project, I had changed the package folders but I had not updated the package in one of the java files.

Most likely cause of this error 'package R does not exist' is that the package name in Java or manifest file is incorrect. Make sure it is correct and in sync and then do a clean build.

JRE 1.7 - java version - returns: java/lang/NoClassDefFoundError: java/lang/Object

Quick Solution for impatient people ;) On Windows machines, try this: Go to C:\Windows\System32 directory and delete java.exe (or rename it to something like java.exe.old).

Since at least 1.6, there should not be a java.exe in the Windows directory. If there is, it's a leftover from something.

A bit more reading:

I'm really suprised that a question from 2012 doesn't have an approved answer yet and I've actually encountered the same issue in 2015 on my Win 7 32-Bit OS!

So what did happen?

Basically, everything was working fine, I downloaded H2 database and when I tried to start H2 Console (Command Line) I got:

Error occurred during initialization of VM
java/lang/NoClassDefFoundError: java/lang/Object

I found this question and I was able to confirm the same symptoms:

JAVA_HOME is set correctly:

echo %JAVA_HOME%
C:\Program Files\Java\jdk1.6.0_26

java -version fails, while java --fullversion works fine:

java -fullversion
java full version "1.6.0_45-b06"

SOLUTION: Go to C:\Windows\System32 directory and delete (I actually renamed) java.exe file!!!!

Now, I get:

java -version
java version "1.6.0_26"
Java(TM) SE Runtime Environment (build 1.6.0_26-b03)
Java HotSpot(TM) Client VM (build 20.1-b02, mixed mode, sharing)

and H2 Console (Command Line) works fine as well!

Credits go to the last post in this forum:

Convert char to int in C and C++

I have absolutely null skills in C, but for a simple parsing:

char* something = "123456";

int number = parseInt(something);

...this worked for me:

int parseInt(char* chars)
    int sum = 0;
    int len = strlen(chars);
    for (int x = 0; x < len; x++)
        int n = chars[len - (x + 1)] - '0';
        sum = sum + powInt(n, x);
    return sum;

int powInt(int x, int y)
    for (int i = 0; i < y; i++)
        x *= 10;
    return x;

Change image source in code behind - Wpf

None of the above solutions worked for me. But this did:

myImage.Source = new BitmapImage(new Uri(@"/Images/foo.png", UriKind.Relative));

Leaflet - How to find existing markers, and delete markers?

(1) add layer group and array to hold layers and reference to layers as global variables:

var search_group = new L.LayerGroup(); var clickArr = new Array();

(2) add map

(3) Add group layer to map


(4) the add to map function, with a popup that contains a link, which when clicked will have a remove option. This link will have, as its id the lat long of the point. This id will then be compared to when you click on one of your created markers and you want to delete it.

 map.on('click', function(e) {
        var clickPositionMarker = L.marker([,e.latlng.lng],{icon: idMarker});
        mapLat =;
        mapLon = e.latlng.lng;
        clickPositionMarker.addTo(search_group).bindPopup("<a name='removeClickM' id=""_"+e.latlng.lng+">Remove Me</a>")

                /*   clickPositionMarker.on('click', function(e) {
                }); */


(5) The remove function, compare the marker lat long to the id fired in the remove:

$(document).on("click","a[name='removeClickM']", function (e) {

      // Stop form from submitting normally

    for(i=0;i<clickArr.length;i++) {

                clickArr.splice(clickArr.indexOf(clickArr[i]), 1);



How to do HTTP authentication in android?

You can manually insert http header to request:

HttpGet request = new HttpGet(...);
request.setHeader("Authorization", "Basic "+Base64.encodeBytes("login:password".getBytes()));

Inconsistent Accessibility: Parameter type is less accessible than method

What is the accessibility of the type support.ACTInterface. The error suggests it is not public.

You cannot expose a public method signature where some of the parameter types of the signature are not public. It wouldn't be possible to call the method from outside since the caller couldn't construct the parameters required.

If you make support.ACTInterface public that will remove this error. Alternatively reduce the accessibility of the form method if possible.

How can I change image tintColor in iOS and WatchKit

For tinting the image of a UIButton

let image1 = "ic_shopping_cart_empty"
btn_Basket.setImage(UIImage(named: image1)?.withRenderingMode(.alwaysTemplate), for: .normal)
btn_Basket.setImage(UIImage(named: image1)?.withRenderingMode(.alwaysTemplate), for: .selected)
btn_Basket.imageView?.tintColor = UIColor(UIColor.Red)

Populating a database in a Laravel migration file

I tried this DB insert method, but as it does not use the model, it ignored a sluggable trait I had on the model. So, given the Model for this table exists, as soon as its migrated, I figured the model would be available to use to insert data. And I came up with this:

public function up() {
        Schema::create('parent_categories', function (Blueprint $table) {
                'id' => 1,
                'name' => 'Occasions',

This worked correctly, and also took into account the sluggable trait on my Model to automatically generate a slug for this entry, and uses the timestamps too. NB. Adding the ID was no neccesary, however, I wanted specific IDs for my categories in this example. Tested working on Laravel 5.8

Android ADB devices unauthorized

I got this as root when as a non-root user I was getting permissions errors trying to connect to custom recovery (Philz). so I killed adb server, copied the .android subdirectory of my user account into /root, chowned -R to root.root, and restarted adb server. I'm in!

Get battery level and state in Android

To check battery percentage we use BatteryManager, the following method will return battery percentage.

Source Link

public static float getBatteryLevel(Context context, Intent intent) {
    Intent batteryStatus = context.registerReceiver(null,
            new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
    int batteryLevel = -1;
    int batteryScale = 1;
    if (batteryStatus != null) {
        batteryLevel = batteryStatus.getIntExtra(BatteryManager.EXTRA_LEVEL, batteryLevel);
        batteryScale = batteryStatus.getIntExtra(BatteryManager.EXTRA_SCALE, batteryScale);
    return batteryLevel / (float) batteryScale * 100;

Add Twitter Bootstrap icon to Input box

For bootstrap 4

        <link rel="stylesheet" href="" integrity="sha384-9gVQ4dYFwwWSjIDZnLEWnxCjeSWFphJiwGPXr1jddIhOegiu1FwO5qRGvFXOdJZ4" crossorigin="anonymous">

            <script src="" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
            <script src="" integrity="sha384-cs/chFZiN24E4KMATLdqdvsezGxaGsi4hLGOzlXwp5UZB1LY//20VyM2taTB4QvJ" crossorigin="anonymous"></script>
            <script src="" integrity="sha384-uefMccjFJAIv6A+rW+L4AHf99KvxDjWSu1z9VI8SKNVmz4sk7buKt/6v9KI65qnm" crossorigin="anonymous"></script>
        <link href="" rel="stylesheet">
        <form class="form-inline my-2 my-lg-0">
                        <div class="input-group">
                            <input class="form-control" type="search" placeholder="Search">
                            <div class="input-group-append">
                                <div class="input-group-text"><i class="fa fa-search"></i></div>


Uninstall Eclipse under OSX?

Eclipse has no impact on Mac OS beyond it directory, so there is no problem uninstalling.

I think that What you are facing is the result of Eclipse switching the plugin distribution system recently. There are now two redundant and not very compatible means of installing plugins. It's a complete mess. You may be better off (if possible) installing a more recent version of Eclipse (maybe even the 3.5 milestones) as they seem to be more stable in that regard.

show loading icon until the page is load?

HTML page

<div id="overlay">
<img src="<?php echo base_url()?>assest/website/images/loading1.gif" alt="Loading" />



How to make git mark a deleted and a new file as a file move?

Git will automatically detect the move/rename if your modification is not too severe. Just git add the new file, and git rm the old file. git status will then show whether it has detected the rename.

additionally, for moves around directories, you may need to:

  1. cd to the top of that directory structure.
  2. Run git add -A .
  3. Run git status to verify that the "new file" is now a "renamed" file

If git status still shows "new file" and not "renamed" you need to follow Hank Gay’s advice and do the move and modify in two separate commits.

How can I verify a Google authentication API access token?

For user check, just post get the access token as accessToken and post it and get the response

you can try in address bar in browsers too, use httppost and response in java also

response will be like

     "issued_to": "",
     "audience": "",
     "user_id": "xxxxxxxxxxxxxxxxxxxxxxx",
     "scope": "",
     "expires_in": 3340,
     "access_type": "offline"

The scope is the given permission of the accessToken. you can check the scope ids in this link

Update: New API post as below

Response will be as

 // These six fields are included in all Google ID Tokens.
 "iss": "",
 "sub": "110169484474386276334",
 "azp": "",
 "aud": "",
 "iat": "1433978353",
 "exp": "1433981953",

 // These seven fields are only included when the user has granted the "profile" and
 // "email" OAuth scopes to the application.
 "email": "[email protected]",
 "email_verified": "true",
 "name" : "Test User",
 "picture": "",
 "given_name": "Test",
 "family_name": "User",
 "locale": "en"

For more info,

jQuery ajax post file field

File uploads can not be done this way, no matter how you break it down. If you want to do an ajax/async upload, I would suggest looking into something like Uploadify, or Valums

Add click event on div tag using javascript

Recommend you to use Id, as Id is associated to only one element while class name may link to more than one element causing confusion to add event to element.

try if you really want to use class:

 document.getElementsByClassName('drill_cursor')[0].onclick = function(){alert('1');};

or you may assign function in html itself:

<div class="drill_cursor" onclick='alert("1");'>

Socket.IO - how do I get a list of connected sockets/clients?

[email protected]

I used Object.Keys to get the array of socket connected. Then in the same array iterate with map function to build a new array of objects

var connectedUsers = Object.keys(io.sockets.connected).map(function(socketId) {
    return { socket_id : socketId, socket_username: io.sockets.connected[socketId].username };

// test

Perhaps this answer can help to get socket id/username array.

JavaScript alert not working in Android WebView

Check this link , and last comment , You have to use WebChromeClient for your purpose.

Uses of content-disposition in an HTTP response header

Note that RFC 6266 supersedes the RFCs referenced below. Section 7 outlines some of the related security concerns.

The authority on the content-disposition header is RFC 1806 and RFC 2183. People have also devised content-disposition hacking. It is important to note that the content-disposition header is not part of the HTTP 1.1 standard.

The HTTP 1.1 Standard (RFC 2616) also mentions the possible security side effects of content disposition:

15.5 Content-Disposition Issues

RFC 1806 [35], from which the often implemented Content-Disposition
(see section 19.5.1) header in HTTP is derived, has a number of very
serious security considerations. Content-Disposition is not part of
the HTTP standard, but since it is widely implemented, we are
documenting its use and risks for implementors. See RFC 2183 [49]
(which updates RFC 1806) for details.

Windows Scheduled task succeeds but returns result 0x1

This answer was originally edited into the question by the asker.

The problem was that the batch file WAS throwing a silent error. The final POPD was doing no work and was incorrectly called with no opening PUSHD.

Broken code:

CD /D "C:\Program Files (x86)\Olim, LLC\Collybus DR Upload" CALL CollybusUpload.exe POPD

Correct code:

PUSHD "C:\Program Files (x86)\Olim, LLC\Collybus DR Upload" CALL CollybusUpload.exe POPD

Plot multiple lines (data series) each with unique color in R

In case the x-axis is a factor / discrete variable, and one would like to keep the order of the variable (different values corresponding to different groups) to visualise the group effect. The following code wold do:


# dummy data
df <- data.frame(x=rep(letters[1:5], 9), val=sample(1:100, 45), 
                   variable=rep(paste0("category", 1:9), each=5))

# This ensures that x-axis (which is a factor variable)  will be ordered appropriately
df$x <- ordered(df$x, levels=letters[1:5])

ggplot(data = df, aes(x=x, y=val, group=variable, color=variable)) + geom_line() + geom_point() + ggtitle("Multiple lines with unique color")

enter image description here Also note that: adding group=variable remove the warning information: "geom_path: Each group consists of only one observation. Do you need to adjust the group aesthetic?"

what is the use of $this->uri->segment(3) in codeigniter pagination

CodeIgniter User Guide says:


Permits you to retrieve a specific segment. Where n is the segment number you wish to retrieve. Segments are numbered from left to right. For example, if your full URL is this:

The segment numbers would be this:

1. news
2. local
3. metro
4. crime_is_up

So segment refers to your url structure segment. By the above example, $this->uri->segment(3) would be 'metro', while $this->uri->segment(4) would be 'crime_is_up'.

Get file name from a file location in Java

Here are 2 ways(both are OS independent.)

Using Paths : Since 1.7

Path p = Paths.get(<Absolute Path of Linux/Windows system>);
String fileName = p.getFileName().toString();
String directory = p.getParent().toString();

Using FilenameUtils in Apache Commons IO :

String name1 = FilenameUtils.getName("/ab/cd/xyz.txt");
String name2 = FilenameUtils.getName("c:\\ab\\cd\\xyz.txt");

MySQL and GROUP_CONCAT() maximum length

The correct syntax is mysql> SET @@global.group_concat_max_len = integer;
If you do not have the privileges to do this on the server where your database resides then use a query like:
mySQL="SET @@session.group_concat_max_len = 10000;"or a different value.
Next line:
SET objRS = objConn.Execute(mySQL)  your variables may be different.
mySQL="SELECT GROUP_CONCAT(......);" etc
I use the last version since I do not have the privileges to change the default value of 1024 globally (using cPanel).
Hope this helps.

Python script to convert from UTF-8 to ASCII

UTF-8 is a superset of ASCII. Either your UTF-8 file is ASCII, or it can't be converted without loss.

How to customize Bootstrap 3 tab color

I think you should edit the anchor tag on bootstrap.css. Otherwise give customized style to the anchor tag with !important (to override the default style on bootstrap.css).

Example code

.nav {_x000D_
    background-color: #000 !important;_x000D_
.nav>li>a {_x000D_
    background-color: #666 !important;_x000D_
    color: #fff;_x000D_
<script src=""></script>_x000D_
<link rel="stylesheet" href="//">_x000D_
<script src="//"></script>_x000D_
<div role="tabpanel">_x000D_
  <!-- Nav tabs -->_x000D_
  <ul class="nav nav-tabs" role="tablist">_x000D_
    <li role="presentation" class="active"><a href="#home" aria-controls="home" role="tab" data-toggle="tab">Home</a></li>_x000D_
    <li role="presentation"><a href="#profile" aria-controls="profile" role="tab" data-toggle="tab">Profile</a></li>_x000D_
    <li role="presentation"><a href="#messages" aria-controls="messages" role="tab" data-toggle="tab">Messages</a></li>_x000D_
    <li role="presentation"><a href="#settings" aria-controls="settings" role="tab" data-toggle="tab">Settings</a></li>_x000D_
  <!-- Tab panes -->_x000D_
  <div class="tab-content">_x000D_
    <div role="tabpanel" class="tab-pane active" id="home">...</div>_x000D_
    <div role="tabpanel" class="tab-pane" id="profile">tab1</div>_x000D_
    <div role="tabpanel" class="tab-pane" id="messages">tab2</div>_x000D_
    <div role="tabpanel" class="tab-pane" id="settings">tab3</div>_x000D_


Why is NULL undeclared?

Are you including "stdlib.h" or "cstdlib" in this file? NULL is defined in stdlib.h/cstdlib

#include <stdlib.h>


#include <cstdlib>  // This is preferrable for c++

SQL Server Output Clause into a scalar variable

You need a table variable and it can be this simple.

declare @ID table (ID int)

insert into MyTable2(ID)
output inserted.ID into @ID
values (1)

Join two data frames, select all columns from one and some columns from the other

Here is the code snippet that does the inner join and select the columns from both dataframe and alias the same column to different column name.

emp_df  ='Employees.csv', header =True);
dept_df ='dept.csv', header =True)

emp_dept_df = emp_df.join(dept_df,'DeptID').select(emp_df['*'], dept_df['Name'].alias('DName'))
Output  for '':

| ID|     Name|Salary|DeptID|
|  1|     John| 20000|     1|
|  2|    Rohit| 15000|     2|
|  3|    Parth| 14600|     3|
|  4|  Rishabh| 20500|     1|
|  5|    Daisy| 34000|     2|
|  6|    Annie| 23000|     1|
|  7| Sushmita| 50000|     3|
|  8| Kaivalya| 20000|     1|
|  9|    Varun| 70000|     3|
| 10|Shambhavi| 21500|     2|
| 11|  Johnson| 25500|     3|
| 12|     Riya| 17000|     2|
| 13|    Krish| 17000|     1|
| 14| Akanksha| 20000|     2|
| 15|   Rutuja| 21000|     3|

Output  for '':
|DeptID|      Name|
|     1|     Sales|
|     2|Accounting|
|     3| Marketing|

Join Output:
| ID|     Name|Salary|DeptID|     DName|
|  1|     John| 20000|     1|     Sales|
|  2|    Rohit| 15000|     2|Accounting|
|  3|    Parth| 14600|     3| Marketing|
|  4|  Rishabh| 20500|     1|     Sales|
|  5|    Daisy| 34000|     2|Accounting|
|  6|    Annie| 23000|     1|     Sales|
|  7| Sushmita| 50000|     3| Marketing|
|  8| Kaivalya| 20000|     1|     Sales|
|  9|    Varun| 70000|     3| Marketing|
| 10|Shambhavi| 21500|     2|Accounting|
| 11|  Johnson| 25500|     3| Marketing|
| 12|     Riya| 17000|     2|Accounting|
| 13|    Krish| 17000|     1|     Sales|
| 14| Akanksha| 20000|     2|Accounting|
| 15|   Rutuja| 21000|     3| Marketing|

jump to line X in nano editor

I am using nano editor in a Raspberry Pi with Italian OS language and Italian keyboard. Don't know the exact reason, but in this environment the shortcut is:


Shift elements in a numpy array

For those who want to just copy and paste the fastest implementation of shift, there is a benchmark and conclusion(see the end). In addition, I introduce fill_value parameter and fix some bugs.


import numpy as np
import timeit

# enhanced from IronManMark20 version
def shift1(arr, num, fill_value=np.nan):
    arr = np.roll(arr,num)
    if num < 0:
        arr[num:] = fill_value
    elif num > 0:
        arr[:num] = fill_value
    return arr

# use np.roll and np.put by IronManMark20
def shift2(arr,num):
    if num<0:
    elif num > 0:
    return arr

# use np.pad and slice by me.
def shift3(arr, num, fill_value=np.nan):
    l = len(arr)
    if num < 0:
        arr = np.pad(arr, (0, abs(num)), mode='constant', constant_values=(fill_value,))[:-num]
    elif num > 0:
        arr = np.pad(arr, (num, 0), mode='constant', constant_values=(fill_value,))[:-num]

    return arr

# use np.concatenate and np.full by chrisaycock
def shift4(arr, num, fill_value=np.nan):
    if num >= 0:
        return np.concatenate((np.full(num, fill_value), arr[:-num]))
        return np.concatenate((arr[-num:], np.full(-num, fill_value)))

# preallocate empty array and assign slice by chrisaycock
def shift5(arr, num, fill_value=np.nan):
    result = np.empty_like(arr)
    if num > 0:
        result[:num] = fill_value
        result[num:] = arr[:-num]
    elif num < 0:
        result[num:] = fill_value
        result[:num] = arr[-num:]
        result[:] = arr
    return result

arr = np.arange(2000).astype(float)

def benchmark_shift1():
    shift1(arr, 3)

def benchmark_shift2():
    shift2(arr, 3)

def benchmark_shift3():
    shift3(arr, 3)

def benchmark_shift4():
    shift4(arr, 3)

def benchmark_shift5():
    shift5(arr, 3)

benchmark_set = ['benchmark_shift1', 'benchmark_shift2', 'benchmark_shift3', 'benchmark_shift4', 'benchmark_shift5']

for x in benchmark_set:
    number = 10000
    t = timeit.timeit('%s()' % x, 'from __main__ import %s' % x, number=number)
    print '%s time: %f' % (x, t)

benchmark result:

benchmark_shift1 time: 0.265238
benchmark_shift2 time: 0.285175
benchmark_shift3 time: 0.473890
benchmark_shift4 time: 0.099049
benchmark_shift5 time: 0.052836


shift5 is winner! It's OP's third solution.

Have a variable in images path in Sass?

Was searching around for an answer to the same question, but think I found a better solution:

Basically, you can set your image path in config.rb and you use the image-url() helper

How to remove a field completely from a MongoDB document?

Checking if "words" exists and then removing from the document

    db.users.update({"tags.words" :{$exists: true}},

true indicates update multiple documents if matched.

Determining the current foreground application from a background task or service

In order to determine the foreground application, you can use for detecting the foreground app, you can use It uses different methods depending on the android version of the device.

As for the service, the repo also provides the code you need for it. Essentially, let android studio create the service for you, and then onCreate add the snippet that uses the appChecker. You will need to request permission however.

How do I get the path and name of the file that is currently executing?

Try this,

import os

sqlite3.OperationalError: unable to open database file

in my case, i tried creating the sqlite db in /tmp folder and from all the slashes i missed a single slash

Instead of sqlite:///tmp/mydb.sqlite -> sqlite:////tmp/mydb.sqlite ...

GZIPInputStream reading line by line

The basic setup of decorators is like this:

InputStream fileStream = new FileInputStream(filename);
InputStream gzipStream = new GZIPInputStream(fileStream);
Reader decoder = new InputStreamReader(gzipStream, encoding);
BufferedReader buffered = new BufferedReader(decoder);

The key issue in this snippet is the value of encoding. This is the character encoding of the text in the file. Is it "US-ASCII", "UTF-8", "SHIFT-JIS", "ISO-8859-9", …? there are hundreds of possibilities, and the correct choice usually cannot be determined from the file itself. It must be specified through some out-of-band channel.

For example, maybe it's the platform default. In a networked environment, however, this is extremely fragile. The machine that wrote the file might sit in the neighboring cubicle, but have a different default file encoding.

Most network protocols use a header or other metadata to explicitly note the character encoding.

In this case, it appears from the file extension that the content is XML. XML includes the "encoding" attribute in the XML declaration for this purpose. Furthermore, XML should really be processed with an XML parser, not as text. Reading XML line-by-line seems like a fragile, special case.

Failing to explicitly specify the encoding is against the second commandment. Use the default encoding at your peril!

How to store the hostname in a variable in a .bat file?

hmm - something like this?

echo %host%

EDIT: expanding on jitter's answer and using a technique in an answer to this question to set an environment variable with the result of running a command line app:

@echo off
hostname.exe > __t.tmp
set /p host=<__t.tmp
del __t.tmp
echo %host%

In either case, 'host' is created as an environment variable.

Amazon S3 upload file and get URL

Below method uploads file in a particular folder in a bucket and return the generated url of the file uploaded.

private String uploadFileToS3Bucket(final String bucketName, final File file) {
    final String uniqueFileName = uploadFolder + "/" + file.getName();"Uploading file with name= " + uniqueFileName);
    final PutObjectRequest putObjectRequest = new PutObjectRequest(bucketName, uniqueFileName, file);
    return ((AmazonS3Client) amazonS3).getResourceUrl(bucketName, uniqueFileName);

How can I use JavaScript in Java?

Java includes a scripting language extension package starting with version 6.

See the Rhino project documentation for embedding a JavaScript interpreter in Java.


Here is a small example of how you can expose Java objects to your interpreted script:

public class JS {
  public static void main(String args[]) throws Exception {
    ScriptEngine js = new ScriptEngineManager().getEngineByName("javascript");
    Bindings bindings = js.getBindings(ScriptContext.ENGINE_SCOPE);
    bindings.put("stdout", System.out);
    // Prints "-1.0" to the standard output stream.

How to update column value in laravel

You may try this:

Page::where('id', $id)->update(array('image' => 'asdasd'));

There are other ways too but no need to use Page::find($id); in this case. But if you use find() then you may try it like this:

$page = Page::find($id);

// Make sure you've got the Page model
if($page) {
    $page->image = 'imagepath';

Also you may use:

$page = Page::findOrFail($id);

So, it'll throw an exception if the model with that id was not found.

error: could not create '/usr/local/lib/python2.7/dist-packages/virtualenv_support': Permission denied

pip is not give permission so can't do pip install.Try below command.

apt-get install python-virtualenv

Convert multidimensional array into single array

Despite that array_column will work nice here, in case you need to flatten any array no matter of it's internal structure you can use this array library to achieve it without ease:

$flattened = Arr::flatten($array);

which will produce exactly the array you want.

How to find the mysql data directory from command line in windows

You can see the complete list of MySQL server options by running

mysqld --verbose --help

For example, to find out the path to the data directory on Linux, you can run:

mysqld --verbose --help | grep ^datadir

Example output:

datadir                                     /var/lib/mysql/

How to convert a HTMLElement to a string

Suppose your element is entire [object HTMLDocument]. You can convert it to a String this way:

const htmlTemplate = `<!DOCTYPE html><html lang="en"><head></head><body></body></html>`;

const domparser = new DOMParser();
const doc = domparser.parseFromString(htmlTemplate, "text/html"); // [object HTMLDocument]

const doctype = '<!DOCTYPE html>';
const html = doc.documentElement.outerHTML;

console.log(doctype + html);

How to display a json array in table format?

using jquery $.each you can access all data and also set in table like this

<table style="width: 100%">
     <tbody id="tbody">

$.each(data, function (index, item) {
     var eachrow = "<tr>"
                 + "<td>" + item[1] + "</td>"
                 + "<td>" + item[2] + "</td>"
                 + "<td>" + item[3] + "</td>"
                 + "<td>" + item[4] + "</td>"
                 + "</tr>";

JSP tricks to make templating easier?

Based on the same basic idea as in @Will Hartung's answer, here is my magic one-tag extensible template engine. It even includes documentation and an example :-)


    The block tag implements a basic but useful extensible template system.

    A base template consists of a block tag without a 'template' attribute.
    The template body is specified in a standard jsp:body tag, which can
    contain EL, JSTL tags, nested block tags and other custom tags, but
    cannot contain scriptlets (scriptlets are allowed in the template file,
    but only outside of the body and attribute tags). Templates can be
    full-page templates, or smaller blocks of markup included within a page.

    The template is customizable by referencing named attributes within
    the body (via EL). Attribute values can then be set either as attributes
    of the block tag element itself (convenient for short values), or by
    using nested jsp:attribute elements (better for entire blocks of markup).

    Rendering a template block or extending it in a child template is then
    just a matter of invoking the block tag with the 'template' attribute set
    to the desired template name, and overriding template-specific attributes
    as necessary to customize it.

    Attribute values set when rendering a tag override those set in the template
    definition, which override those set in its parent template definition, etc.
    The attributes that are set in the base template are thus effectively used
    as defaults. Attributes that are not set anywhere are treated as empty.

    Internally, attributes are passed from child to parent via request-scope
    attributes, which are removed when rendering is complete.

    Here's a contrived example:

    ====== WEB-INF/tags/block.tag (the template engine tag)

    <the file you're looking at right now>

    ====== WEB-INF/templates/base.jsp (base template)

    <%@ page trimDirectiveWhitespaces="true" %>
    <%@ taglib prefix="t" tagdir="/WEB-INF/tags" %>
        <jsp:attribute name="title">Template Page</jsp:attribute>
        <jsp:attribute name="style">
            .footer { font-size: smaller; color: #aaa; }
            .content { margin: 2em; color: #009; }
        <jsp:attribute name="footer">
            <div class="footer">
                Powered by the block tag
                    <div class="content">

    ====== WEB-INF/templates/history.jsp (child template)

    <%@ page trimDirectiveWhitespaces="true" %>
    <%@ taglib prefix="t" tagdir="/WEB-INF/tags" %>
    <t:block template="base" title="History Lesson">
        <jsp:attribute name="content" trim="false">
            <p>${shooter} shot first!</p>

    ====== history-1977.jsp (a page using child template)

    <%@ page trimDirectiveWhitespaces="true" %>
    <%@ taglib prefix="t" tagdir="/WEB-INF/tags" %>
    <t:block template="history" shooter="Han" />

    ====== history-1997.jsp (a page using child template)

    <%@ page trimDirectiveWhitespaces="true" %>
    <%@ taglib prefix="t" tagdir="/WEB-INF/tags" %>
    <t:block template="history" title="Revised History Lesson">
        <jsp:attribute name="moreStyle">.revised { font-style: italic; }</jsp:attribute>
        <jsp:attribute name="shooter"><span class="revised">Greedo</span></jsp:attribute>


<%@ tag trimDirectiveWhitespaces="true" %>
<%@ tag import="java.util.HashSet, java.util.Map, java.util.Map.Entry" %>
<%@ tag dynamic-attributes="dynattributes" %>
<%@ attribute name="template" %>
    // get template name (adding default .jsp extension if it does not contain
    // any '.', and /WEB-INF/templates/ prefix if it does not start with a '/')
    String template = (String)jspContext.getAttribute("template");
    if (template != null) {
        if (!template.contains("."))
            template += ".jsp";
        if (!template.startsWith("/"))
            template = "/WEB-INF/templates/" + template;
    // copy dynamic attributes into request scope so they can be accessed from included template page
    // (child is processed before parent template, so only set previously undefined attributes)
    Map<String, String> dynattributes = (Map<String, String>)jspContext.getAttribute("dynattributes");
    HashSet<String> addedAttributes = new HashSet<String>();
    for (Map.Entry<String, String> e : dynattributes.entrySet()) {
        if (jspContext.getAttribute(e.getKey(), PageContext.REQUEST_SCOPE) == null) {
            jspContext.setAttribute(e.getKey(), e.getValue(), PageContext.REQUEST_SCOPE);

<% if (template == null) { // this is the base template itself, so render it %>
<% } else { // this is a page using the template, so include the template instead %>
    <jsp:include page="<%= template %>" />
<% } %>

    // clean up the added attributes to prevent side effect outside the current tag
    for (String key : addedAttributes) {
        jspContext.removeAttribute(key, PageContext.REQUEST_SCOPE);

Check key exist in python dict

Use the in keyword.

if 'apples' in d:
    if d['apples'] == 20:
        print('20 apples')
        print('Not 20 apples')

If you want to get the value only if the key exists (and avoid an exception trying to get it if it doesn't), then you can use the get function from a dictionary, passing an optional default value as the second argument (if you don't pass it it returns None instead):

if d.get('apples', 0) == 20:
    print('20 apples.')
    print('Not 20 apples.')

"No cached version... available for offline mode."

With the new Android Studio 3.6 to toggle Gradle's offline mode go to View > Tool Windows > Gradle from the menu bar and toggle the value of Offline Mode that is near the top of the Gradle window.

enter image description here

enter image description here

How can I draw vertical text with CSS cross-browser?

I've had problems trying to do it in pure CSS - depending on the font it can look a bit rubbish. As an alternative you can use SVG/VML to do it. There are libraries that help make it cross browser with ease e.g. Raphael and ExtJS. In ExtJS4 the code looks like this:

    var drawComp = Ext.create('Ext.draw.Component', {
        renderTo: Ext.getBody(), //or whatever..
        height: 100, width: 100 //ditto..
    var text = Ext.create('Ext.draw.Component', {
        type: "text",
        text: "The text to draw",
        rotate: {
            x: 0, y: 0, degrees: 270
        x: -50, y: 10 //or whatever to fit (you could calculate these)..

This will work in IE6+ and all modern browsers, however, unfortunately I think you need at least FF3.0.

How do I count unique items in field in Access query?

Access-Engine does not support


You have to do it like this:

SELECT count(*) 

Its a little workaround... you're counting a DISTINCT selection.

Pandas convert dataframe to array of tuples

The most efficient and easy way:


You can filter the columns you need before this call.

Facebook API "This app is in development mode"

for testing purposes only you could Go to your facebook developer dashboard. create your app then in the top left corner open the apps dropdown menu and click create test app take the app ID and use instead.


Linq to Sql: Multiple left outer joins

In VB.NET using Function,

Dim query = From order In dc.Orders
            From vendor In 
            dc.Vendors.Where(Function(v) v.Id = order.VendorId).DefaultIfEmpty()
            From status In 
            dc.Status.Where(Function(s) s.Id = order.StatusId).DefaultIfEmpty()
            Select Order = order, Vendor = vendor, Status = status 

PHP convert string to hex and hex to string

Using @bill-shirley answer with a little addition

function str_to_hex($string) {
$hexstr = unpack('H*', $string);
return array_shift($hexstr);
function hex_to_str($string) {
return hex2bin("$string");


  $str = "Go placidly amidst the noise";
  $hexstr = str_to_hex($str);// 476f20706c616369646c7920616d6964737420746865206e6f697365
  $strstr = hex_to_str($str);// Go placidly amidst the noise

find: missing argument to -exec

Try putting a space before each \;


find . -name "*.log" -exec echo {} \;

Doesn't Work:

find . -name "*.log" -exec echo {}\;

Best way to reverse a string

"Best" can depend on many things, but here are few more short alternatives ordered from fast to slow:

string s = "z?a"l?g¨o?", pattern = @"(?s).(?<=(?:.(?=.*$(?<=((\P{M}\p{C}?\p{M}*)\1?))))*)";

string s1 = string.Concat(s.Reverse());                          // "???o¨g?l"a?z"  

string s2 = Microsoft.VisualBasic.Strings.StrReverse(s);         // "o?g¨l?a"?z"  

string s3 = string.Concat(StringInfo.ParseCombiningCharacters(s).Reverse()
    .Select(i => StringInfo.GetNextTextElement(s, i)));          // "o?g¨l?a"z?"  

string s4 = Regex.Replace(s, pattern, "$2").Remove(s.Length);    // "o?g¨l?a"z?"  

how to change listen port from default 7001 to something different?

if your port is 7001, since it's the default it might not be mentioned in the config.xml. config.xml only reports stuff which differs from the default, for sake of simplicity.

apart from the config.xml, you should look into a number of other places under your domain-home:




And don't forget to update any internal URIs of your deployed code.

See also

Especially changing the listen address/port of the admin can be troublesome. If you change only the managed server, it's a lot easier.

The best option is just rebuilding the domain.

How to run jenkins as a different user


Started by user anonymous

That does not mean that Jenkins started as an anonymous user.

It just means that the person who started the build was not logged in. If you enable Jenkins security, you can create usernames for people and when they log in, the

"Started by anonymous" 

will change to

"Started by < username >". 

Note: You do not have to enable security in order to run jenkins or to clone correctly.

If you want to enable security and create users, you should see the options at Manage Jenkins > Configure System.


The "can't clone" error is a different issue altogether. It has nothing to do with you logging in to jenkins or enabling security. It just means that Jenkins does not have the credentials to clone from your git SCM.

Check out the Jenkins Git Plugin to see how to set up Jenkins to work with your git repository.

Hope that helps.

CSS endless rotation animation

Without any prefixes, e.g. at it's simplest:

.loading-spinner {
  animation: rotate 1.5s linear infinite;

@keyframes rotate {
  to {
    transform: rotate(360deg);

How to resize the jQuery DatePicker control

To get this to work in Safari 5.1 with Rails 3.1, I had to add:

.ui-datepicker, .ui-datepicker a{

jquery animate background position

jQuery's animate function is not exclusively usable for directly animating properties of DOM-objects. You can also tween variables and use the step function to get the variables for every step of the tween.

For example, to animate a background-position from background-position(0px 0px) to background-position(100px 500px) you can do this:

$({temporary_x: 0, temporary_y: 0}).animate({temporary_x: 100, temporary_y: 500}, {
    duration: 1000,
    step: function() {
        var position = Math.round(this.temporary_x) + "px " + Math.round(this.temporary_y) + "px";
        $("#your_div").css("background-position",  position);

Just make sure to not forget the this. inside the step function.

"Adaptive Server is unavailable or does not exist" error connecting to SQL Server from PHP

I've found an issue happen to be with the Firewall. So, make sure your IP is whitelisted and the firewall does not block your connection. You can check connectivity with:

tsql -H -p 1433

In my case, the output was:

Error 20009 (severity 9):
  Unable to connect: Adaptive Server is unavailable or does not exist
  OS error 111, "Connection refused"
There was a problem connecting to the server

Windows batch: sleep

You can try

ping -n XXX >nul

where XXX is the number of seconds to wait, plus one.

Enabling CORS in Cloud Functions for Firebase

If none of the other solutions work, you could try adding the below address at the beginning of the call to enable CORS - redirect:

Sample code with JQuery AJAX request:

   url: '[email protected],
   type: 'GET'

How to fix ReferenceError: primordials is not defined in node

You Have Two Option Here

  1. Either upgrade to gulp 4 Or Else
  2. downgrade to an earlier node version.

How do I put the image on the right side of the text in a UIButton?

Took @Piotr's answer and made it into a Swift extension. Make sure to set the image and title before calling this, so that the button sizes properly.

 extension UIButton {
    /// Makes the ``imageView`` appear just to the right of the ``titleLabel``.
    func alignImageRight() {
        if let titleLabel = self.titleLabel, imageView = self.imageView {
            // Force the label and image to resize.
            imageView.contentMode = .ScaleAspectFit
            // Set the insets so that the title appears to the left and the image appears to the right. 
            // Make the image appear slightly off the top/bottom edges of the button.
            self.titleEdgeInsets = UIEdgeInsets(top: 0, left: -1 * imageView.frame.size.width,
                bottom: 0, right: imageView.frame.size.width)
            self.imageEdgeInsets = UIEdgeInsets(top: 4, left: titleLabel.frame.size.width,
                bottom: 4, right: -1 * titleLabel.frame.size.width)

Importing a long list of constants to a Python file

If you really want constants, not just variables looking like constants, the standard way to do it is to use immutable dictionaries. Unfortunately it's not built-in yet, so you have to use third party recipes (like this one or that one).

Find all files in a folder

You can try with Directory.GetFiles and fix your pattern

 string[] files = Directory.GetFiles(@"c:\", "*.txt");

 foreach (string file in files)
    File.Copy(file, "....");

 Or Move

 foreach (string file in files)
    File.Move(file, "....");

Why doesn't calling a Python string method do anything unless you assign its output?

This is because strings are immutable in Python.

Which means that X.replace("hello","goodbye") returns a copy of X with replacements made. Because of that you need replace this line:

X.replace("hello", "goodbye")

with this line:

X = X.replace("hello", "goodbye")

More broadly, this is true for all Python string methods that change a string's content "in-place", e.g. replace,strip,translate,lower/upper,join,...

You must assign their output to something if you want to use it and not throw it away, e.g.

X  = X.strip(' \t')
X2 = X.translate(...)
Y  = X.lower()
Z  = X.upper()
A  = X.join(':')
B  = X.capitalize()
C  = X.casefold()

and so on.

How to validate a form with multiple checkboxes to have atleast one checked

Here is the a quick solution for multiple checkbox validation using jquery validation plugin:

jQuery.validator.addMethod('atLeastOneChecked', function(value, element) {
  return ($('.cbgroup input:checked').length > 0);

  rules: {
    list0: { atLeastOneChecked: true }
  messages: {
    list0: { 'Please check at least one option' }

$('.cbgroup input').click(function() {

Gradle: How to Display Test Results in the Console in Real Time?

My favourite minimalistic version based on Shubham Chaudhary answer. enter image description here

Put this in build.gradle file:

test {
    afterSuite { desc, result ->
    if (!desc.parent)
        println("${result.resultType} " +
            "(${result.testCount} tests, " +
            "${result.successfulTestCount} successes, " +
            "${result.failedTestCount} failures, " +
            "${result.skippedTestCount} skipped)")

Object array initialization without default constructor

My way

Car * cars;

// else were

extern Car * cars;

void main()
    // COLORS == id
    cars = new Car[3] {

How to Convert the value in DataTable into a string array in c#

If that's all what you want to do, you don't need to convert it into an array. You can just access it as:

string myData=yourDataTable.Rows[0][1].ToString();//Gives you USA

Android Location Providers - GPS or Network Provider?

GPS is generally more accurate than network but sometimes GPS is not available, therefore you might need to switch between the two.

A good start might be to look at the android dev site. They had a section dedicated to determining user location and it has all the code samples you need.

How to copy data from one HDFS to another HDFS?

It's also useful to note that you can run the underlying MapReduce jobs with either the source or target cluster like so:

hadoop --config /path/to/hadoop/config distcp <src> <dst>

ImportError: cannot import name NUMPY_MKL

yes,Just reinstall numpy,it works.

How to grey out a button?

You have to provide 3 or 4 states in your btn_defaut.xml as a selector.

  1. Pressed state
  2. Default state
  3. Focus state
  4. Enabled state (Disable state with false indication; see comments)

You will provide effect and background for the states accordingly.

Here is a detailed discussion: Standard Android Button with a different color

Using ResourceManager

I went through a similar issue. If you consider your "YeagerTechResources.Resources", it means that your Resources.resx is at the root folder of your project.

Be careful to include the full path eg : "project\subfolder(s)\file[.resx]" to the ResourceManager constructor.

Django: OperationalError No Such Table

It looks like there was an issue with my migration.

I ran ./ schemamigration research --auto and found that many of the fields didn't have a default specified.

So, I ran ./ schemamigration research --init followed by ./ migrate research

Rerunning the server from there did the trick!

Twitter - share button, but with image

To create a Twitter share link with a photo, you first need to tweet out the photo from your Twitter account. Once you've tweeted it out, you need to grab the link and place that inside your twitter share url.

note: You won't be able to see the url so what I do is use a separate account and hit the retweet button. A modal will pop up with the link inside.

You Twitter share link will look something like this:

<a href="!">Share on Twitter</a>

Check date with todays date

public static boolean itIsToday(long date){
    boolean result = false;
        Calendar calendarData = Calendar.getInstance();
        calendarData.set(Calendar.HOUR_OF_DAY, 0);
        calendarData.set(Calendar.MINUTE, 0);
        calendarData.set(Calendar.SECOND, 0);
        calendarData.set(Calendar.MILLISECOND, 0);

        Calendar calendarToday = Calendar.getInstance();
        calendarToday.set(Calendar.HOUR_OF_DAY, 0);
        calendarToday.set(Calendar.MINUTE, 0);
        calendarToday.set(Calendar.SECOND, 0);
        calendarToday.set(Calendar.MILLISECOND, 0);

        if(calendarToday.getTimeInMillis() == calendarData.getTimeInMillis()) {
            result = true;
    }catch (Exception exception){
        Log.e(TAG, exception);
    return result;

C# Get a control's position on a form

I usually combine PointToScreen and PointToClient:

Point locationOnForm = control.FindForm().PointToClient(

Remove a symlink to a directory

On CentOS, just run rm linkname and it will ask to "remove symbolic link?". Type Y and Enter, the link will be gone and the directory be safe.

How to update Python?

I have always just installed the new version on top and never had any issues. Do make sure that your path is updated to point to the new version though.

Does Java have a complete enum for HTTP response codes?

If you are using Netty, you can use:

How can I create a dynamically sized array of structs?

Your code in the last update should not compile, much less run. You're passing &x to LoadData. &x has the type of **words, but LoadData expects words* . Of course it crashes when you call realloc on a pointer that's pointing into stack.

The way to fix it is to change LoadData to accept words** . Thi sway, you can actually modify the pointer in main(). For example, realloc call would look like

*x = (words*) realloc(*x, sizeof(words)*2);

It's the same principlae as in "num" being int* rather than int.

Besides this, you need to really figure out how the strings in words ere stored. Assigning a const string to char * (as in str2 = "marley\0") is permitted, but it's rarely the right solution, even in C.

Another point: non need to have "marley\0" unless you really need two 0s at the end of string. Compiler adds 0 tho the end of every string literal.

How do I send an HTML Form in an Email .. not just MAILTO

I actually use ASP C# to send my emails now, with something that looks like :

protected void Page_Load(object sender, EventArgs e)
    if (Request.Form.Count > 0)
        string formEmail = "";
        string fromEmail = "[email protected]";
        string defaultEmail = "[email protected]";

        string sendTo1 = "";

        int x = 0;

        for (int i = 0; i < Request.Form.Keys.Count; i++)
            formEmail += "<strong>" + Request.Form.Keys[i] + "</strong>";
            formEmail += ": " + Request.Form[i] + "<br/>";
            if (Request.Form.Keys[i] == "Email")
                if (Request.Form[i].ToString() != string.Empty)
                    fromEmail = Request.Form[i].ToString();
                formEmail += "<br/>";

        System.Net.Mail.MailMessage myMsg = new System.Net.Mail.MailMessage();
        SmtpClient smtpClient = new SmtpClient();

            myMsg.To.Add(new System.Net.Mail.MailAddress(defaultEmail));
            myMsg.IsBodyHtml = true;
            myMsg.Body = formEmail;
            myMsg.From = new System.Net.Mail.MailAddress(fromEmail);
            myMsg.Subject = "Sent using Gmail Smtp";
            smtpClient.Host = "";
            smtpClient.Port = 587;
            smtpClient.EnableSsl = true;
            smtpClient.UseDefaultCredentials = true;
            smtpClient.Credentials = new System.Net.NetworkCredential("[email protected]", "pward");

            smtpClient.Send(defaultEmail, sendTo1, "Sent using gmail smpt", formEmail);

        catch (Exception ee)
            debug.Text += ee.Message;

This is an example using gmail as the smtp mail sender. Some of what is in here isn't needed, but it is how I use it, as I am sure there are more effective ways in the same fashion.

how to call url of any other website in php

As other's have mentioned, PHP's cURL functions will allow you to perform advanced HTTP requests. You can also use file_get_contents to access REST APIs:

$payload = file_get_contents('');

Starting with PHP 5 you can also create a stream context which will allow you to change headers or post data to the service.

Querying data by joining two tables in two database on different servers

If a linked server is not allowed by your dba, you can use OPENROWSET. Books Online will provide the syntax you need.

json.decoder.JSONDecodeError: Extra data: line 2 column 1 (char 190)

I was parsing JSON from a REST API call and got this error. It turns out the API had become "fussier" (eg about order of parameters etc) and so was returning malformed results. Check that you are getting what you expect :)

How do you determine the size of a file in C?

Try this --

fseek(fp, 0, SEEK_END);
unsigned long int file_size = ftell(fp);

What this does is first, seek to the end of the file; then, report where the file pointer is. Lastly (this is optional) it rewinds back to the beginning of the file. Note that fp should be a binary stream.

file_size contains the number of bytes the file contains. Note that since (according to climits.h) the unsigned long type is limited to 4294967295 bytes (4 gigabytes) you'll need to find a different variable type if you're likely to deal with files larger than that.

How to unpublish an app in Google Play Developer Console

In the current version of Google Play store Console as of(August 2017) here is the procedure of unpublishing your app.

  • Choose the app you wish to unpublish.
  • Go to Store presence > Pricing & distribution.
  • You will see "unpublish" button in the app availability section as shown below. enter image description here

After clicking unpublish a dialog will popup confirm and save the changes.

ASP.NET MVC 404 Error Handling

I've investigated A LOT on how to properly manage 404s in MVC (specifically MVC3), and this, IMHO is the best solution I've come up with:

In global.asax:

public class MvcApplication : HttpApplication
    protected void Application_EndRequest()
        if (Context.Response.StatusCode == 404)

            var rd = new RouteData();
            rd.DataTokens["area"] = "AreaName"; // In case controller is in another area
            rd.Values["controller"] = "Errors";
            rd.Values["action"] = "NotFound";

            IController c = new ErrorsController();
            c.Execute(new RequestContext(new HttpContextWrapper(Context), rd));


public sealed class ErrorsController : Controller
    public ActionResult NotFound()
        ActionResult result;

        object model = Request.Url.PathAndQuery;

        if (!Request.IsAjaxRequest())
            result = View(model);
            result = PartialView("_NotFound", model);

        return result;


If you're using IoC (e.g. AutoFac), you should create your controller using:

var rc = new RequestContext(new HttpContextWrapper(Context), rd);
var c = ControllerBuilder.Current.GetControllerFactory().CreateController(rc, "Errors");

Instead of

IController c = new ErrorsController();
c.Execute(new RequestContext(new HttpContextWrapper(Context), rd));



There are 6 scenarios that I can think of where an ASP.NET MVC3 apps can generate 404s.

Generated by ASP.NET:

  • Scenario 1: URL does not match a route in the route table.

Generated by ASP.NET MVC:

  • Scenario 2: URL matches a route, but specifies a controller that doesn't exist.

  • Scenario 3: URL matches a route, but specifies an action that doesn't exist.

Manually generated:

  • Scenario 4: An action returns an HttpNotFoundResult by using the method HttpNotFound().

  • Scenario 5: An action throws an HttpException with the status code 404.

  • Scenario 6: An actions manually modifies the Response.StatusCode property to 404.


  • (A) Show a custom 404 error page to the user.

  • (B) Maintain the 404 status code on the client response (specially important for SEO).

  • (C) Send the response directly, without involving a 302 redirection.

Solution Attempt: Custom Errors

    <customErrors mode="On">
        <error statusCode="404" redirect="~/Errors/NotFound"/>

Problems with this solution:

  • Does not comply with objective (A) in scenarios (1), (4), (6).
  • Does not comply with objective (B) automatically. It must be programmed manually.
  • Does not comply with objective (C).

Solution Attempt: HTTP Errors

    <httpErrors errorMode="Custom">
        <remove statusCode="404"/>
        <error statusCode="404" path="App/Errors/NotFound" responseMode="ExecuteURL"/>

Problems with this solution:

  • Only works on IIS 7+.
  • Does not comply with objective (A) in scenarios (2), (3), (5).
  • Does not comply with objective (B) automatically. It must be programmed manually.

Solution Attempt: HTTP Errors with Replace

    <httpErrors errorMode="Custom" existingResponse="Replace">
        <remove statusCode="404"/>
        <error statusCode="404" path="App/Errors/NotFound" responseMode="ExecuteURL"/>

Problems with this solution:

  • Only works on IIS 7+.
  • Does not comply with objective (B) automatically. It must be programmed manually.
  • It obscures application level http exceptions. E.g. can't use customErrors section, System.Web.Mvc.HandleErrorAttribute, etc. It can't only show generic error pages.

Solution Attempt customErrors and HTTP Errors

    <customErrors mode="On">
        <error statusCode="404" redirect="~/Errors/NotFound"/>


    <httpErrors errorMode="Custom">
        <remove statusCode="404"/>
        <error statusCode="404" path="App/Errors/NotFound" responseMode="ExecuteURL"/>

Problems with this solution:

  • Only works on IIS 7+.
  • Does not comply with objective (B) automatically. It must be programmed manually.
  • Does not comply with objective (C) in scenarios (2), (3), (5).

People that have troubled with this before even tried to create their own libraries (see But the previous solution seems to cover all the scenarios without the complexity of using an external library.

How to fix Python Numpy/Pandas installation?

I had the same problem and, in my case, the problem was that python was looking for packages in some ordered locations, first of all the default computer one where default old packages are.

To check what your python is looking for you can do:

>>> import sys
>>> print '\n'.join(sys.path)

This was outputting the directory '/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python' before pip or brew or port folders.

The simple solution is:

export PYTHONPATH="/Library/Python/2.7/site-packages:$PYTHONPATH"

This worked well for me, I advise you to add this line to your home bash_profile file for the next time. Remember that sys.path is built using the current working directory, followed by the directories in the PYTHONPATH environment variable. Then there are the installation-dependent default dirs.

plot different color for different categorical levels using matplotlib

You can convert the categorical column into a numerical one by using the commands:

#we converting it into categorical data
cat_col = df['column_name'].astype('categorical') 

#we are getting codes for it 
cat_col = 

# we are using c parameter to change the color.
plt.scatter(df['column1'],df['column2'], c=cat_col) 

Chain-calling parent initialisers in python

The way you are doing it is indeed the recommended one (for Python 2.x).

The issue of whether the class is passed explicitly to super is a matter of style rather than functionality. Passing the class to super fits in with Python's philosophy of "explicit is better than implicit".

How to override the [] operator in Python?

You need to use the __getitem__ method.

class MyClass:
    def __getitem__(self, key):
        return key * 2

myobj = MyClass()
myobj[3] #Output: 6

And if you're going to be setting values you'll need to implement the __setitem__ method too, otherwise this will happen:

>>> myobj[5] = 1
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: MyClass instance has no attribute '__setitem__'

Java creating .jar file

Often you need to put more into the manifest than what you get with the -e switch, and in that case, the syntax is:

jar -cvfm myJar.jar myManifest.txt myApp.class

Which reads: "create verbose jarFilename manifestFilename", followed by the files you want to include.

Note that the name of the manifest file you supply can be anything, as jar will automatically rename it and put it into the right place within the jar file.

Pointer-to-pointer dynamic two-dimensional array

The first method cannot be used to create dynamic 2D arrays because by doing:

int *board[4];

you essentially allocated an array of 4 pointers to int on stack. Therefore, if you now populate each of these 4 pointers with a dynamic array:

for (int i = 0; i < 4; ++i) {
  board[i] = new int[10];

what you end-up with is a 2D array with static number of rows (in this case 4) and dynamic number of columns (in this case 10). So it is not fully dynamic because when you allocate an array on stack you should specify a constant size, i.e. known at compile-time. Dynamic array is called dynamic because its size is not necessary to be known at compile-time, but can rather be determined by some variable in runtime.

Once again, when you do:

int *board[4];


const int x = 4; // <--- `const` qualifier is absolutely needed in this case!
int *board[x];

you supply a constant known at compile-time (in this case 4 or x) so that compiler can now pre-allocate this memory for your array, and when your program is loaded into the memory it would already have this amount of memory for the board array, that's why it is called static, i.e. because the size is hard-coded and cannot be changed dynamically (in runtime).

On the other hand, when you do:

int **board;
board = new int*[10];


int x = 10; // <--- Notice that it does not have to be `const` anymore!
int **board;
board = new int*[x];

the compiler does not know how much memory board array will require, and therefore it does not pre-allocate anything. But when you start your program, the size of array would be determined by the value of x variable (in runtime) and the corresponding space for board array would be allocated on so-called heap - the area of memory where all programs running on your computer can allocate unknown beforehand (at compile-time) amounts memory for personal usage.

As a result, to truly create dynamic 2D array you have to go with the second method:

int **board;
board = new int*[10]; // dynamic array (size 10) of pointers to int

for (int i = 0; i < 10; ++i) {
  board[i] = new int[10];
  // each i-th pointer is now pointing to dynamic array (size 10) of actual int values

We've just created an square 2D array with 10 by 10 dimensions. To traverse it and populate it with actual values, for example 1, we could use nested loops:

for (int i = 0; i < 10; ++i) {   // for each row
  for (int j = 0; j < 10; ++j) { // for each column
    board[i][j] = 1;

PHP error: Notice: Undefined index:

I did define all the variables that was the first thing I checked. I know it's not required in PHP, but old habits die hard. Then I sanatized the info like this:

  if (empty($_POST["name1"])) {
    $name1Err = " First Name is a required field.";
  } else {
      $name1 = test_input($_POST["name1"]);
    // check if name only contains letters and whitespace
      if (!preg_match("/^[a-zA-Z ]*$/",$name1)) {
      $name1Err = "Only letters and white space allowed";

of course test_input is another function that does a trim, strilashes, and htmlspecialchars. I think the input is pretty well sanitized. Not trying to be rude just showing what I did. When it came to the email I also checked to see if it was the proper format. I think the real answer is in the fact that some variables are local and some are global. I have got it working without errors for now so, while I'm extremely busy right now I'll accept shutting off errors as my answer. Don't worry I'll figure it out it's just not vitally important right now!

jQuery/JavaScript: accessing contents of an iframe

I create a sample code . Now you can easily understand from different domain you can't access content of iframe .. Same domain we can access iframe content

I share you my code , Please run this code check the console . I print image src at console. There are four iframe , two iframe coming from same domain & other two from other domain(third party) .You can see two image src(

and ) at console and also can see two permission error( 2 Error: Permission denied to access property 'document'

...irstChild)},contents:function(a){return m.nodeName(a,"iframe")?a.contentDocument...

) which is coming from third party iframe.

<body id="page-top" data-spy="scroll" data-target=".navbar-fixed-top">
<p>iframe from same domain</p>
  <iframe frameborder="0" scrolling="no" width="500" height="500"
   src="iframe.html" name="imgbox" class="iView">

<p>iframe from same domain</p>
<iframe frameborder="0" scrolling="no" width="500" height="500"
   src="iframe2.html" name="imgbox" class="iView1">

<p>iframe from different  domain</p>
 <iframe frameborder="0" scrolling="no" width="500" height="500"
   src="" name="imgbox" class="iView2">


<p>iframe from different  domain</p>
 <iframe frameborder="0" scrolling="no" width="500" height="500"
   src="" name="imgbox" class="iView3">


<script type='text/javascript'>


        var src = $('.iView').contents().find(".shrinkToFit").attr('src');
         }, 2000);


        var src = $('.iView1').contents().find(".shrinkToFit").attr('src');
         }, 3000);


        var src = $('.iView2').contents().find(".shrinkToFit").attr('src');
         }, 3000);


        var src = $('.iView3').contents().find("img").attr('src');
         }, 3000);



Print a variable in hexadecimal in Python


print " ".join("0x%s"%my_string[i:i+2] for i in range(0, len(my_string), 2))

like this:

>>> my_string = "deadbeef"
>>> print " ".join("0x%s"%my_string[i:i+2] for i in range(0, len(my_string), 2))
0xde 0xad 0xbe 0xef

On an unrelated side note ... using string as a variable name even as an example variable name is very bad practice.

IF-THEN-ELSE statements in postgresql

case when field1>0 then field2/field1 else 0 end as field3

Is there an addHeaderView equivalent for RecyclerView?

Native API doesn't have such "addHeader" feature, but has the concept of "addItem".

I was able to include this specific feature of headers and extends for footers as well in my FlexibleAdapter project. I called it Scrollable Headers and Footers.

Here how they work:

Scrollable Headers and Footers are special items that scroll along with all others, but they don't belongs to main items (business items) and they are always handled by the adapter beside the main items. Those items are persistently located at the first and last positions.

enter image description here

There's a lot to say about them, better to read the detailed wiki page.

Moreover the FlexibleAdapter allows you to create headers/sections, also you can have them sticky and tens of others features like expandable items, endless scroll, UI extensions etc... all in one library!

How to save traceback / sys.exc_info() values in a variable?

Use traceback.extract_stack() if you want convenient access to module and function names and line numbers.

Use ''.join(traceback.format_stack()) if you just want a string that looks like the traceback.print_stack() output.

Notice that even with ''.join() you will get a multi-line string, since the elements of format_stack() contain \n. See output below.

Remember to import traceback.

Here's the output from traceback.extract_stack(). Formatting added for readability.

>>> traceback.extract_stack()
   ('<string>', 1, '<module>', None),
   ('C:\\Python\\lib\\idlelib\\', 126, 'main', 'ret = method(*args, **kwargs)'),
   ('C:\\Python\\lib\\idlelib\\', 353, 'runcode', 'exec(code, self.locals)'),
   ('<pyshell#1>', 1, '<module>', None)

Here's the output from ''.join(traceback.format_stack()). Formatting added for readability.

>>> ''.join(traceback.format_stack())
'  File "<string>", line 1, in <module>\n
   File "C:\\Python\\lib\\idlelib\\", line 126, in main\n
       ret = method(*args, **kwargs)\n
   File "C:\\Python\\lib\\idlelib\\", line 353, in runcode\n
       exec(code, self.locals)\n  File "<pyshell#2>", line 1, in <module>\n'

1114 (HY000): The table is full

I fixed this problem by increasing the amount of memory available to the vagrant VM where the database was located.

One line if in VB .NET

If (X1= 1) Then : Val1= "Yes" : Else : Val1= "Not" : End If

C#: How to add subitems in ListView


ListViewItem item = new ListViewItem("Column1Text")
   { Tag = optionalRefToSourceObject };


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

Please find below another way to make the same thing.

This procedure also takes in a schema name as a parameter in case you need it to access your table.

@TableName nchar(50),
@TableSchema nvarchar(50) = ''

DECLARE @TableToBeExported as nvarchar(50);

DECLARE @OUTPUT TABLE (col1 nvarchar(max));
DECLARE @colnamestable VARCHAR(max);
select @colnamestable = COALESCE(@colnamestable, '') +COLUMN_NAME+ ','

SELECT @colnamestable = LEFT(@colnamestable,DATALENGTH(@colnamestable)-1)

select @colnamestable

DECLARE @selectstatement VARCHAR(max);
select @selectstatement = COALESCE(@selectstatement, '') + 'Convert(nvarchar(100),'+COLUMN_NAME+')+'',''+'

SELECT @selectstatement = LEFT(@selectstatement,DATALENGTH(@selectstatement)-1)

DECLARE @sqlstatment as nvarchar(max);

SET @TableToBeExported = @TableSchema+'.'+@TableToBeExported

SELECT @sqlstatment = N'Select '+@selectstatement+N' from '+@TableToBeExported

exec sp_executesql @stmt = @sqlstatment


Android - how to replace part of a string by another string?


I noticed that you commented in 2011 but i thought i should post this answer anyway, in case anyone needs to "replace the original string" and runs into this answer ..

Im using a EditText as an example


 EditText textbox = (EditText) findViewById(;


 String oldText = "hello"
 String newText = "Hi";      
 String textBoxText = textbox.getText().toString();


String returnedString = textBoxText.replace( oldText, newText );



This is untested, but it's just an example of using the returned string to replace the original layouts string with setText() !

Obviously this example requires that you have a EditText with the ID set to your_textboxID

Finish all activities at a time

I was struggling with the same problem. Opening the about page and calling finish(); from there wasn't closing the app instead was going to previous activity and I wanted to close the app from the about page itself.

This is the code which worked for me:

Intent startMain = new Intent(Intent.ACTION_MAIN); 

Hope this helps.

Best way to extract a subvector from a vector?

If both are not going to be modified (no adding/deleting items - modifying existing ones is fine as long as you pay heed to threading issues), you can simply pass around data.begin() + 100000 and data.begin() + 101000, and pretend that they are the begin() and end() of a smaller vector.

Or, since vector storage is guaranteed to be contiguous, you can simply pass around a 1000 item array:

T *arrayOfT = &data[0] + 100000;
size_t arrayOfTLength = 1000;

Both these techniques take constant time, but require that the length of data doesn't increase, triggering a reallocation.

Laravel Migration table already exists, but I want to add new not the older

You can delete all the tables but it will be not a good practice, instead try this command

php artisan migrate:fresh

Make sure to use the naming convention correctly. I have tested this in version laravel 5.7 It is important to not try this command when your site is on server because it drops all information.

Creating a recursive method for Palindrome

Here I am pasting code for you:

But, I would strongly suggest you to know how it works,

from your question , you are totally unreadable.

Try understanding this code. Read the comments from code

import java.util.Scanner;
public class Palindromes

    public static boolean isPal(String s)
        if(s.length() == 0 || s.length() == 1)
            // if length =0 OR 1 then it is
            return true; 
        if(s.charAt(0) == s.charAt(s.length()-1))
            // check for first and last char of String:
            // if they are same then do the same thing for a substring
            // with first and last char removed. and carry on this
            // until you string completes or condition fails
            return isPal(s.substring(1, s.length()-1));

        // if its not the case than string is not.
        return false;

    public static void main(String[]args)
        Scanner sc = new Scanner(;
        System.out.println("type a word to check if its a palindrome or not");
        String x = sc.nextLine();
            System.out.println(x + " is a palindrome");
            System.out.println(x + " is not a palindrome");

Laravel 5 PDOException Could Not Find Driver

If your database is PostgreSQL and you have php7.2 you should run the following commands:

sudo apt-get install php7.2-pgsql


php artisan migrate

Android - How To Override the "Back" button so it doesn't Finish() my Activity?

In Kotlin:

val callback = requireActivity().onBackPressedDispatcher.addCallback(this) {
    // Handle the back button event

For more information you can check this.

There is also specific question about overriding back button in Kotlin.

What is the python keyword "with" used for?

In python the with keyword is used when working with unmanaged resources (like file streams). It is similar to the using statement in VB.NET and C#. It allows you to ensure that a resource is "cleaned up" when the code that uses it finishes running, even if exceptions are thrown. It provides 'syntactic sugar' for try/finally blocks.

From Python Docs:

The with statement clarifies code that previously would use try...finally blocks to ensure that clean-up code is executed. In this section, I’ll discuss the statement as it will commonly be used. In the next section, I’ll examine the implementation details and show how to write objects for use with this statement.

The with statement is a control-flow structure whose basic structure is:

with expression [as variable]:

The expression is evaluated, and it should result in an object that supports the context management protocol (that is, has __enter__() and __exit__() methods).

Update fixed VB callout per Scott Wisniewski's comment. I was indeed confusing with with using.

How can I send an HTTP POST request to a server from Excel using VBA?

To complete the response of the other users:

For this I have created an "WinHttp.WinHttpRequest.5.1" object.

Send a post request with some data from Excel using VBA:

Dim LoginRequest As Object
Set LoginRequest = CreateObject("WinHttp.WinHttpRequest.5.1")
LoginRequest.Open "POST", "http://...", False
LoginRequest.setRequestHeader "Content-type", "application/x-www-form-urlencoded"
LoginRequest.send ("key1=value1&key2=value2")

Send a get request with token authentication from Excel using VBA:

Dim TCRequestItem As Object
Set TCRequestItem = CreateObject("WinHttp.WinHttpRequest.5.1")
TCRequestItem.Open "GET", "http://...", False
TCRequestItem.setRequestHeader "Content-Type", "application/xml"
TCRequestItem.setRequestHeader "Accept", "application/xml"
TCRequestItem.setRequestHeader "Authorization", "Bearer " & token

How do I write to a Python subprocess' stdin?

To clarify some points:

As jro has mentioned, the right way is to use subprocess.communicate.

Yet, when feeding the stdin using subprocess.communicate with input, you need to initiate the subprocess with stdin=subprocess.PIPE according to the docs.

Note that if you want to send data to the process’s stdin, you need to create the Popen object with stdin=PIPE. Similarly, to get anything other than None in the result tuple, you need to give stdout=PIPE and/or stderr=PIPE too.

Also qed has mentioned in the comments that for Python 3.4 you need to encode the string, meaning you need to pass Bytes to the input rather than a string. This is not entirely true. According to the docs, if the streams were opened in text mode, the input should be a string (source is the same page).

If streams were opened in text mode, input must be a string. Otherwise, it must be bytes.

So, if the streams were not opened explicitly in text mode, then something like below should work:

import subprocess
command = ['myapp', '--arg1', 'value_for_arg1']
p = subprocess.Popen(command, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
output = p.communicate(input='some data'.encode())[0]

I've left the stderr value above deliberately as STDOUT as an example.

That being said, sometimes you might want the output of another process rather than building it up from scratch. Let's say you want to run the equivalent of echo -n 'CATCH\nme' | grep -i catch | wc -m. This should normally return the number characters in 'CATCH' plus a newline character, which results in 6. The point of the echo here is to feed the CATCH\nme data to grep. So we can feed the data to grep with stdin in the Python subprocess chain as a variable, and then pass the stdout as a PIPE to the wc process' stdin (in the meantime, get rid of the extra newline character):

import subprocess

what_to_catch = 'catch'
what_to_feed = 'CATCH\nme'

# We create the first subprocess, note that we need stdin=PIPE and stdout=PIPE
p1 = subprocess.Popen(['grep', '-i', what_to_catch], stdin=subprocess.PIPE, stdout=subprocess.PIPE)

# We immediately run the first subprocess and get the result
# Note that we encode the data, otherwise we'd get a TypeError
p1_out = p1.communicate(input=what_to_feed.encode())[0]

# Well the result includes an '\n' at the end, 
# if we want to get rid of it in a VERY hacky way
p1_out = p1_out.decode().strip().encode()

# We create the second subprocess, note that we need stdin=PIPE
p2 = subprocess.Popen(['wc', '-m'], stdin=subprocess.PIPE, stdout=subprocess.PIPE)

# We run the second subprocess feeding it with the first subprocess' output.
# We decode the output to convert to a string
# We still have a '\n', so we strip that out
output = p2.communicate(input=p1_out)[0].decode().strip()

This is somewhat different than the response here, where you pipe two processes directly without adding data directly in Python.

Hope that helps someone out.

Summing radio input values

Your javascript is executed before the HTML is generated, so it doesn't "see" the ungenerated INPUT elements. For jQuery, you would either stick the Javascript at the end of the HTML or wrap it like this:

<script type="text/javascript">   $(function() { //jQuery trick to say after all the HTML is parsed.     $("input[type=radio]").click(function() {       var total = 0;       $("input[type=radio]:checked").each(function() {         total += parseFloat($(this).val());       });        $("#totalSum").val(total);     });   }); </script> 

EDIT: This code works for me

<!DOCTYPE html> <html> <head> <meta charset="utf-8"> </head> <body>   <strong>Choose a base package:</strong>   <input id="item_0" type="radio" name="pkg" value="1942" />Base Package 1 - $1942   <input id="item_1" type="radio" name="pkg" value="2313" />Base Package 2 - $2313   <input id="item_2" type="radio" name="pkg" value="2829" />Base Package 3 - $2829   <strong>Choose an add on:</strong>   <input id="item_10" type="radio" name="ext" value="0" />No add-on - +$0   <input id="item_12" type="radio" name="ext" value="2146" />Add-on 1 - (+$2146)   <input id="item_13" type="radio" name="ext" value="2455" />Add-on 2 - (+$2455)   <input id="item_14" type="radio" name="ext" value="2764" />Add-on 3 - (+$2764)   <input id="item_15" type="radio" name="ext" value="3073" />Add-on 4 - (+$3073)   <input id="item_16" type="radio" name="ext" value="3382" />Add-on 5 - (+$3382)   <input id="item_17" type="radio" name="ext" value="3691" />Add-on 6 - (+$3691)   <strong>Your total is:</strong>   <input id="totalSum" type="text" name="totalSum" readonly="readonly" size="5" value="" />   <script src=""></script>   <script type="text/javascript">       $("input[type=radio]").click(function() {         var total = 0;         $("input[type=radio]:checked").each(function() {           total += parseFloat($(this).val());         });          $("#totalSum").val(total);       });     </script> </body> </html> 

internet explorer 10 - how to apply grayscale filter?

Inline SVG can be used in IE 10 and 11 and Edge 12.

I've created a project called gray which includes a polyfill for these browsers. The polyfill switches out <img> tags with inline SVG:

To implement, the short version is to download the jQuery plugin at the GitHub link above and add after jQuery at the end of your body:

<script src="/js/jquery.gray.min.js"></script>

Then every image with the class grayscale will appear as gray.

<img src="/img/color.jpg" class="grayscale">

You can see a demo too if you like.

Copying data from one SQLite database to another

First scenario: DB1.sqlite and DB2.sqlite have the same table(t1), but DB1 is more "up to date" than DB2. If it's small, drop the table from DB2 and recreate it with the data:


Second scenario: If it's a large table, you may be better off with an INSERT if not exists type solution. If you have a Unique Key column it's more straight forward, otherwise you'd need to use a combination of fields (maybe every field) and at some point it's still faster to just drop and re-create the table; it's always more straight forward (less thinking required).

THE SETUP: open SQLite without a DB which creates a temporary in memory main database, then attach DB1.sqlite and DB2.sqlite

> sqlite3
sqlite> ATTACH "DB1.sqlite" AS db1
sqlite> ATTACH "DB2.sqlite" AS db2

and use .databases to see the attached databases and their files.

sqlite> .databases
db1: /db/DB1.sqlite
db2: /db/DB2.sqlite

How to remove carriage returns and new lines in Postgresql?

select regexp_replace(field, E'[\\n\\r\\u2028]+', ' ', 'g' )

I had the same problem in my postgres d/b, but the newline in question wasn't the traditional ascii CRLF, it was a unicode line separator, character U2028. The above code snippet will capture that unicode variation as well.

Update... although I've only ever encountered the aforementioned characters "in the wild", to follow lmichelbacher's advice to translate even more unicode newline-like characters, use this:

select regexp_replace(field, E'[\\n\\r\\f\\u000B\\u0085\\u2028\\u2029]+', ' ', 'g' )

C++ JSON Serialization

The jsoncons C++ header-only library also supports conversion between JSON text and C++ objects. Decode and encode are defined for all C++ classes that have json_type_traits defined. The standard library containers are already supported, and json_type_traits can be specialized for user types in the jsoncons namespace.

Below is an example:

#include <iostream>
#include <jsoncons/json.hpp>

namespace ns {
    enum class hiking_experience {beginner,intermediate,advanced};

    class hiking_reputon
        std::string rater_;
        hiking_experience assertion_;
        std::string rated_;
        double rating_;
        hiking_reputon(const std::string& rater,
                       hiking_experience assertion,
                       const std::string& rated,
                       double rating)
            : rater_(rater), assertion_(assertion), rated_(rated), rating_(rating)

        const std::string& rater() const {return rater_;}
        hiking_experience assertion() const {return assertion_;}
        const std::string& rated() const {return rated_;}
        double rating() const {return rating_;}

    class hiking_reputation
        std::string application_;
        std::vector<hiking_reputon> reputons_;
        hiking_reputation(const std::string& application, 
                          const std::vector<hiking_reputon>& reputons)
            : application_(application), 

        const std::string& application() const { return application_;}
        const std::vector<hiking_reputon>& reputons() const { return reputons_;}

} // namespace ns

// Declare the traits using convenience macros. Specify which data members need to be serialized.

JSONCONS_ENUM_TRAITS_DECL(ns::hiking_experience, beginner, intermediate, advanced)
JSONCONS_ALL_CTOR_GETTER_TRAITS(ns::hiking_reputon, rater, assertion, rated, rating)
JSONCONS_ALL_CTOR_GETTER_TRAITS(ns::hiking_reputation, application, reputons)

using namespace jsoncons; // for convenience

int main()

std::string data = R"(
       "application": "hiking",
       "reputons": [
           "rater": "HikingAsylum",
           "assertion": "advanced",
           "rated": "Marilyn C",
           "rating": 0.90

    // Decode the string of data into a c++ structure
    ns::hiking_reputation v = decode_json<ns::hiking_reputation>(data);

    // Iterate over reputons array value
    std::cout << "(1)\n";
    for (const auto& item : v.reputons())
        std::cout << item.rated() << ", " << item.rating() << "\n";

    // Encode the c++ structure into a string
    std::string s;
    encode_json<ns::hiking_reputation>(v, s, indenting::indent);
    std::cout << "(2)\n";
    std::cout << s << "\n";


Marilyn C, 0.9
    "application": "hiking",
    "reputons": [
            "assertion": "advanced",
            "rated": "Marilyn C",
            "rater": "HikingAsylum",
            "rating": 0.9

#pragma mark in Swift?

//MARK: does not seem to work for me in Xcode 6.3.2. However, this is what I did to get it to work:

1) Code:

import Cocoa

class MainWindowController: NSWindowController {

    //MARK: - My cool methods

    func fly() {

    func turnInvisible() {


2) In the jump bar nothing appears to change when adding the //MARK: comment. However, if I click on the rightmost name in the jump bar, in my case it says MainWindowController(with a leading C icon), then a popup window will display showing the effects of the //MARK: comment, namely a heading that says "My cool methods":

enter image description here

3) I also notice that if I click on one of the methods in my code, then the method becomes the rightmost entry in the jump bar. In order to get MainWindowController(with a leading C icon) to be the rightmost entry in the jump bar, I have to click on the whitespace above my methods.

Break out of a While...Wend loop

Another option would be to set a flag variable as a Boolean and then change that value based on your criteria.

Dim count as Integer 
Dim flag as Boolean

flag = True

While flag
    count = count + 1 

    If count = 10 Then
        'Set the flag to false         '
        flag = false
    End If 

How to set child process' environment variable in Makefile

Make variables are not exported into the environment of processes make invokes... by default. However you can use make's export to force them to do so. Change:

test: NODE_ENV = test

to this:

test: export NODE_ENV = test

(assuming you have a sufficiently modern version of GNU make >= 3.77 ).

How to get past the login page with Wget?

A solution which uses lynx and wget.

Note: Lynx has to have been compiled with the --enable-persistent-cookies flag for this to work

When you want to use wget to download some file from a site which requires login, you just need a cookie file. In order to generate the cookie file, I choose lynx. lynx is a text web browser. First you need a configure file for lynx to save cookie. Create a file lynx.cfg. Write these configuration into the file.


Then start lynx with this command:

lynx -cfg=lynx.cfg

After you input the username and password, and select 'preserve me on this pc' or something similar. If login successfully, you will see a beautiful text web page of the site. And you logout. The in the current directory, you will find a cookie file named as cookie.file. This is what we need for wget.

Then wget can download file from the site with this command.

wget --load-cookies ./cookie.file

Detect when browser receives file download

In my experience, there are two ways to handle this:

  1. Set a short-lived cookie on the download, and have JavaScript continually check for its existence. Only real issue is getting the cookie lifetime right - too short and the JS can miss it, too long and it might cancel the download screens for other downloads. Using JS to remove the cookie upon discovery usually fixes this.
  2. Download the file using fetch/XHR. Not only do you know exactly when the file download finishes, if you use XHR you can use progress events to show a progress bar! Save the resulting blob with msSaveBlob in IE/Edge and a download link (like this one) in Firefox/Chrome. The problem with this method is that iOS Safari doesn't seem to handle downloading blobs right - you can convert the blob into a data URL with a FileReader and open that in a new window, but that's opening the file, not saving it.

Circle line-segment collision detection algorithm?

Okay, I won't give you code, but since you have tagged this , I don't think that will matter to you. First, you have to get a vector perpendicular to the line.

You will have an unknown variable in y = ax + c ( c will be unknown )
To solve for that, Calculate it's value when the line passes through the center of the circle.

That is,
Plug in the location of the circle center to the line equation and solve for c.
Then calculate the intersection point of the original line and its normal.

This will give you the closest point on the line to the circle.
Calculate the distance between this point and the circle center (using the magnitude of the vector).
If this is less than the radius of the circle - voila, we have an intersection!

Room - Schema export directory is not provided to the annotation processor so we cannot export the schema

Probably you didn't add your room class to child RoomDatabase child class in @Database(entities = {your_classes})

Install a Windows service using a Windows command prompt?

You should open command prompt, go to

C:\windows\\framework\v4.0.30319\InstallUtil.exe -i ".EXE file of window service"

How can I set the 'backend' in matplotlib in Python?

For new comers,


Maven: mvn command not found

I think the problem is with the spaces. I had my variable at the System variables but it didn't work. When I changed variable Progra~1 = 'Program Files' everything works fine.

M2_HOME C:\Progra~1\Maven\apache-maven-3.1.1

I also moved my M2_HOME at the end of the PATH(%M2_HOME%\bin) I'm not sure if this has any difference.

what's the easiest way to put space between 2 side-by-side buttons in

If you are using bootstrap, add ml-3 to your second button:

 <div class="row justify-content-center mt-5">
        <button class="btn btn-secondary" type="button">Button1</button>
        <button class="btn btn-secondary ml-3" type="button">Button2</button>

How do I edit $PATH (.bash_profile) on OSX?

In Macbook, step by step:

  1. First of all open terminal and write it: cd ~/
  2. Create your bash file: touch .bash_profile

You created your ".bash_profile" file but if you would like to edit it, you should write it;

  1. Edit your bash profile: open -e .bash_profile

After you can save from top-left corner of screen: File > Save


Setting up a websocket on Apache?

The new version 2.4 of Apache HTTP Server has a module called mod_proxy_wstunnel which is a websocket proxy.

anaconda - path environment variable in windows

You can also run conda init as below,

C:\ProgramData\Anaconda3\Scripts\conda init cmd.exe


C:\ProgramData\Anaconda3\Scripts\conda init powershell

Note that the execution policy of powershell must be set, e.g. using Set-ExecutionPolicy Unrestricted.

Build error: You must add a reference to System.Runtime

I needed to download and install the Windows 8.0 (and not 8.1) SDK to make the error disappear on my TeamCity server.

What is the best way to test for an empty string with jquery-out-of-the-box?

Based on David's answer I personally like to check the given object first if it is a string at all. Otherwise calling .trim() on a not existing object would throw an exception:

function isEmpty(value) {
  return typeof value == 'string' && !value.trim() || typeof value == 'undefined' || value === null;


isEmpty(undefined); // true
isEmpty(null); // true
isEmpty(''); // true
isEmpty('foo'); // false
isEmpty(1); // false
isEmpty(0); // false