SyntaxFix

Programs & Examples On #Arrayobject

ArrayObject class allows objects to work as arrays in PHP. Properties of the object have their normal functionality when accessed as list. Use this tag for questions related to arrayobject.

Create an array with random values

Generators

An array of length 40 of 40 random possible values (0 - 39) without repeating values is better to shuffle it as @Phrogz and @Jared Beck explain. Another approach, just for the records, could be using generators. But this approach lacks of performance compared to other proposed solutions.

function* generateRandomIterable(n, range) {
  for (let i = 0; i < n; i++) {
    yield ~~(Math.random() * range);
  }
}
const randomArr = [...generateRandomIterable(40,40)];

How to see if an object is an array without using reflection?

Simply obj instanceof Object[] (tested on JShell).

Convert Little Endian to Big Endian

I think you can use function htonl(). Network byte order is big endian.

String length in bytes in JavaScript

Actually, I figured out what's wrong. For the code to work the page <head> should have this tag:

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

Or, as suggested in comments, if server sends HTTP Content-Encoding header, it should work as well.

Then results from different browsers are consistent.

Here is an example: 

<html>
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 
  <title>mini string length test</title>
</head>
<body>

<script type="text/javascript">
document.write('<div style="font-size:100px">' 
    + (unescape(encodeURIComponent("???! Naïve?")).length) + '</div>'
  );
</script>
</body>
</html>

Note: I suspect that specifying any (accurate) encoding would fix the encoding problem. It is just a coincidence that I need UTF-8.

How to pip install a package with min and max version range?

An elegant method would be to use the ~= compatible release operator according to PEP 440. In your case this would amount to:

package~=0.5.0

As an example, if the following versions exist, it would choose 0.5.9:

  • 0.5.0
  • 0.5.9
  • 0.6.0

For clarification, each pair is equivalent:

~= 0.5.0
>= 0.5.0, == 0.5.*

~= 0.5
>= 0.5, == 0.*

SFTP in Python? (platform independent)

You can use the pexpect module

Here is a good intro post

child = pexpect.spawn ('/usr/bin/sftp ' + [email protected] )
child.expect ('.* password:')
child.sendline (your_password)
child.expect ('sftp> ')
child.sendline ('dir')
child.expect ('sftp> ')
file_list = child.before
child.sendline ('bye')

I haven't tested this but it should work

How to run DOS/CMD/Command Prompt commands from VB.NET?

 
Imports System.IO
Public Class Form1
    Public line, counter As String
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        counter += 1
        If TextBox1.Text = "" Then
            MsgBox("Enter a DNS address to ping")
        Else
            'line = ":start" + vbNewLine
            'line += "ping " + TextBox1.Text
            'MsgBox(line)
            Dim StreamToWrite As StreamWriter
            StreamToWrite = New StreamWriter("C:\Desktop\Ping" + counter + ".bat")
            StreamToWrite.Write(":start" + vbNewLine + _
                                "Ping -t " + TextBox1.Text)
            StreamToWrite.Close()
            Dim p As New System.Diagnostics.Process()
            p.StartInfo.FileName = "C:\Desktop\Ping" + counter + ".bat"
            p.Start()
        End If
    End Sub
End Class

This works as well

Uncaught TypeError: data.push is not a function

Try This Code $scope.DSRListGrid.data = data; this one for source data 

            for (var prop in data[0]) {
                if (data[0].hasOwnProperty(prop)) {
                    $scope.ListColumns.push(
                            {
                                "name": prop,
                                "field": prop,
                                "width": 150,
                                "headerCellClass": 'font-12'
                            }
                    );
                }
            }
            console.log($scope.ListColumns);

Issue when importing dataset: `Error in scan(...): line 1 did not have 145 elements`

Hash # symbol creating this error, if you can remove the # from the start of the column name, it could fix the problem.

Basically, when the column name starts with # in between rows, read.table() will recognise as a starting point for that row.

Javascript: Load an Image from url and display

Add a div with ID imgDiv and make your script

 document.getElementById('imgDiv').innerHTML='<img src=\'http://webpage.com/images/'+document.getElementById('imagename').value +'.png\'>'

I tried to stay as close to your original as tp not overwhelm you with jQuery and such

How can I write data attributes using Angular?

About access

<ol class="viewer-nav">
    <li *ngFor="let section of sections" 
        [attr.data-sectionvalue]="section.value"
        (click)="get_data($event)">
        {{ section.text }}
    </li>  
</ol>

And

get_data(event) {
   console.log(event.target.dataset.sectionvalue)
}

How to URL encode a string in Ruby

I created a gem to make URI encoding stuff cleaner to use in your code. It takes care of binary encoding for you.

Run gem install uri-handler, then use:

require 'uri-handler'

str = "\x12\x34\x56\x78\x9a\xbc\xde\xf1\x23\x45\x67\x89\xab\xcd\xef\x12\x34\x56\x78\x9a".to_uri
# => "%124Vx%9A%BC%DE%F1%23Eg%89%AB%CD%EF%124Vx%9A"

It adds the URI conversion functionality into the String class. You can also pass it an argument with the optional encoding string you would like to use. By default it sets to encoding 'binary' if the straight UTF-8 encoding fails.

How to convert the background to transparent?

For Photoshop you need to download Photoshop portable.... Load image e press "w" click in image e suave as png or gif....

Git - Won't add files?

Issue git would not add a changed file. Using git bash, I had changed folder delimiting the folder name with the double quote. ls displayed the folder contents correctly but git would not add changed files.

Solution I used the single quote to delimit the folder name.

e.g. CD "Folder Name" git status nothing to commit, working tree clean CD .. ls 'Folder Name' CD 'Folder Name' git status modified: ModifiedFileName.bat

SSL "Peer Not Authenticated" error with HttpClient 4.1

This is thrown when

... the peer was not able to identify itself (for example; no certificate, the particular cipher suite being used does not support authentication, or no peer authentication was established during SSL handshaking) this exception is thrown.

Probably the cause of this exception (where is the stacktrace) will show you why this exception is thrown. Most likely the default keystore shipped with Java does not contain (and trust) the root certificate of the TTP that is being used.

The answer is to retrieve the root certificate (e.g. from your browsers SSL connection), import it into the cacerts file and trust it using keytool which is shipped by the Java JDK. Otherwise you will have to assign another trust store programmatically.

WPF checkbox binding

You need a dependency property for this:

public BindingList<User> Users
{
    get { return (BindingList<User>)GetValue(UsersProperty); }
    set { SetValue(UsersProperty, value); }
}

public static readonly DependencyProperty UsersProperty =
    DependencyProperty.Register("Users", typeof(BindingList<User>), 
      typeof(OptionsDialog));

Once that is done, you bind the checkbox to the dependency property:

<CheckBox x:Name="myCheckBox"
          IsChecked="{Binding ElementName=window1, Path=CheckBoxIsChecked}" />

For that to work you have to name your Window or UserControl in its openning tag, and use that name in the ElementName parameter.

With this code, whenever you change the property on the code side, you will change the textbox. Also, whenever you check/uncheck the textbox, the Dependency Property will change too.

EDIT:

An easy way to create a dependency property is typing the snippet propdp, which will give you the general code for Dependency Properties.

All the code:

XAML:

<Window x:Class="StackOverflowTests.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" x:Name="window1" Height="300" Width="300">
    <Grid>
        <StackPanel Orientation="Vertical">
            <CheckBox Margin="10"
                      x:Name="myCheckBox"
                      IsChecked="{Binding ElementName=window1, Path=IsCheckBoxChecked}">
                Bound CheckBox
            </CheckBox>
            <Label Content="{Binding ElementName=window1, Path=IsCheckBoxChecked}"
                   ContentStringFormat="Is checkbox checked? {0}" />
        </StackPanel>
    </Grid>
</Window>

C#:

using System.Windows;

namespace StackOverflowTests
{
    /// <summary>
    /// Interaction logic for Window1.xaml
    /// </summary>
    public partial class Window1 : Window
    {
        public bool IsCheckBoxChecked
        {
           get { return (bool)GetValue(IsCheckBoxCheckedProperty); }
           set { SetValue(IsCheckBoxCheckedProperty, value); }
        }

        // Using a DependencyProperty as the backing store for 
         //IsCheckBoxChecked.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty IsCheckBoxCheckedProperty =
            DependencyProperty.Register("IsCheckBoxChecked", typeof(bool), 
            typeof(Window1), new UIPropertyMetadata(false));

        public Window1()
        {             
            InitializeComponent();
        }
    }
}

Notice how the only code behind is the Dependency Property. Both the label and the checkbox are bound to it. If the checkbox changes, the label changes too.

Installing Bower on Ubuntu

on Ubuntu 12.04 and the packaged version of NodeJs is too old to install Bower using the PPA 

sudo add-apt-repository ppa:chris-lea/node.js 
sudo apt-get update
sudo apt-get -y install nodejs

When this has installed, check the version:

npm --version
1.4.3

Now install Bower:

sudo npm install -g bower

This will fetch and install Bower globally.

Getting the thread ID from a thread

The offset under Windows 10 is 0x022C (x64-bit-Application) and 0x0160 (x32-bit-Application):

public static int GetNativeThreadId(Thread thread)
{
    var f = typeof(Thread).GetField("DONT_USE_InternalThread",
        BindingFlags.GetField | BindingFlags.NonPublic | BindingFlags.Instance);

    var pInternalThread = (IntPtr)f.GetValue(thread);
    var nativeId = Marshal.ReadInt32(pInternalThread, (IntPtr.Size == 8) ? 0x022C : 0x0160); // found by analyzing the memory
    return nativeId;
}

How to add jQuery in JS file

just copy the code from the two files into your file at the top.

or use something like this http://code.google.com/p/minify/ to combine your files dynamically.

Josh

Is it possible to run .APK/Android apps on iPad/iPhone devices?

It is not natively possible to run Android application under iOS (which powers iPhone, iPad, iPod, etc.)

This is because both runtime stacks use entirely different approaches. Android runs Dalvik (a "variant of Java") bytecode packaged in APK files while iOS runs Compiled (from Obj-C) code from IPA files. Excepting time/effort/money and litigations (!), there is nothing inherently preventing an Android implementation on Apple hardware, however.

It looks to package a small Dalvik VM with each application and targeted towards developers.

See iPhoDroid:

Looks to be a dual-boot solution for 2G/3G jailbroken devices. Very little information available, but there are some YouTube videos.

See iAndroid:

iAndroid is a new iOS application for jailbroken devices that simulates the Android operating system experience on the iPhone or iPod touch. While it’s still very far from completion, the project is taking shape.

I am not sure the approach(es) it uses to enable this: it could be emulation or just a simulation (e.g. "looks like"). The requirement of being jailbroken makes it sound like emulation might be used ..

See BlueStacks, per the Holo Dev's comment:

It looks to be an "Android App Player" for OS X (and Windows). However, afaik, it does not [currently] target iOS devices ..

YMMV

Creating pdf files at runtime in c#

Well, free and not-for-free, I use WebSuperGoo ABCpdf .NET component, that I just love it!

not-for-free because you need to pay for it.

for free because even if you have to pay, they have a trial version and you can request a free license if you do not mind that, in your site show "This site uses WebSuperGoo ABCpdf .NET component" with a link to their website.

I did that and I got a free license (version 5 in that time) so, I can say that it works (even if the website is no longer online) - I still have and use the component ~:)

A wonderful thing that I love with this is that you can do everything that you can thing off with this, create PDF forms and dynamically fill them and send to user by mail or have them to download it, create a pdf from scratch, convert HTML pages into PDF, etc etc etc, please read the documentation, it is a wonderful component.

How do I enable FFMPEG logging and where can I find the FFMPEG log file?

appears that if you add this to the command line:

 -loglevel debug

or

 -loglevel verbose

You get more verbose debugging output to the command line.

Slide right to left Android Animations

You can do Your own Animation style as an xml file like this(put it in anim folder):

left to right:

  <set xmlns:android="http://schemas.android.com/apk/res/android"
     android:shareInterpolator="false">
        <translate android:fromXDelta="-100%" android:toXDelta="0%"
         android:fromYDelta="0%" android:toYDelta="0%"
         android:duration="500"/>
  </set>

right to left:

    <set xmlns:android="http://schemas.android.com/apk/res/android"
     android:shareInterpolator="false">
     <translate
        android:fromXDelta="0%" android:toXDelta="100%"
        android:fromYDelta="0%" android:toYDelta="0%"
        android:duration="500" />
   </set>

here You can set Your own values at duration, maybe it depends on the phone model how the animation will look like, try some values out if it looks not good.

and then You can call it in Your activity:

     Intent animActivity = new Intent(this,YourStartAfterAnimActivity.class);
      startActivity(nextActivity);

      overridePendingTransition(R.anim.your_left_to_right, R.anim.your_right_to_left);

Forking / Multi-Threaded Processes | Bash

Let me try example

for x in 1 2 3 ; do { echo a $x ; sleep 1 ; echo b $x ; } &  done ; sleep 10

And use jobs to see what's running.

ActiveXObject creation error " Automation server can't create object"

i also have same problem and solve it. Please go through the link

add your site to trusted zone and change following options in ie Tools Menu -> Internet Options -> Security -> Custom level -> "Initialize and script ActiveX controls not marked as safe for scripting"

http://forums.codeguru.com/showthread.php?t=256114

Phonegap Cordova installation Windows

I too struggled a lot with phonegap steps.

The correct documentation is at the following link. http://docs.phonegap.com/en/edge/guide_cli_index.md.html

There is no more cordova command, It is replaced with phonegap.

Algorithm to return all combinations of k elements from n

Here's some simple code that prints all the C(n,m) combinations. It works by initializing and moving a set of array indices that point to next valid combination. The indices are initialized to point to the lowest m indices (lexicographically the smallest combination). Then on, starting with the m-th index, we try to move the indices forward. if an index has reached its limit, we try the previous index (all the way down to index 1). If we can move an index forward, then we reset all greater indices.

m=(rand()%n)+1; // m will vary from 1 to n

for (i=0;i<n;i++) a[i]=i+1;

// we want to print all possible C(n,m) combinations of selecting m objects out of n
printf("Printing C(%d,%d) possible combinations ...\n", n,m);

// This is an adhoc algo that keeps m pointers to the next valid combination
for (i=0;i<m;i++) p[i]=i; // the p[.] contain indices to the a vector whose elements constitute next combination

done=false;
while (!done)
{
    // print combination
    for (i=0;i<m;i++) printf("%2d ", a[p[i]]);
    printf("\n");

    // update combination
    // method: start with p[m-1]. try to increment it. if it is already at the end, then try moving p[m-2] ahead.
    // if this is possible, then reset p[m-1] to 1 more than (the new) p[m-2].
    // if p[m-2] can not also be moved, then try p[m-3]. move that ahead. then reset p[m-2] and p[m-1].
    // repeat all the way down to p[0]. if p[0] can not also be moved, then we have generated all combinations.
    j=m-1;
    i=1;
    move_found=false;
    while ((j>=0) && !move_found)
    {
        if (p[j]<(n-i)) 
        {
            move_found=true;
            p[j]++; // point p[j] to next index
            for (k=j+1;k<m;k++)
            {
                p[k]=p[j]+(k-j);
            }
        }
        else
        {
            j--;
            i++;
        }
    }
    if (!move_found) done=true;
}

PHP Fatal error: Call to undefined function mssql_connect()

php.ini probably needs to read: extension=ext\php_sqlsrv_53_nts.dll

Or move the file to same directory as the php executable. This is what I did to my php5 install this week to get odbc_pdo working. :P

Additionally, that doesn't look like proper phpinfo() output. If you make a file with contents
<? phpinfo(); ?> and visit that page, the HTML output should show several sections, including one with loaded modules. (Edited to add: like shown in the screenshot of the above accepted answer)

Convert Enum to String

I create a "Description" extension method and attach it to the enum so that i can get truly user-friendly naming that includes spaces and casing. I have never liked using the enum value itself as displayable text because it is something we developers use to create more readable code. It is not intended for UI display purposes. I want to be able to change the UI without going through and changing enums all over.

Is the NOLOCK (Sql Server hint) bad practice?

With NOLOCK hint, the transaction isolation level for the SELECT statement is READ UNCOMMITTED. This means that the query may see dirty and inconsistent data.

This is not a good idea to apply as a rule. Even if this dirty read behavior is OK for your mission critical web based application, a NOLOCK scan can cause 601 error which will terminate the query due to data movement as a result of lack of locking protection.

I suggest reading When Snapshot Isolation Helps and When It Hurts - the MSDN recommends using READ COMMITTED SNAPSHOT rather than SNAPSHOT under most circumstances.

sklearn plot confusion matrix with labels

You might be interested by https://github.com/pandas-ml/pandas-ml/

which implements a Python Pandas implementation of Confusion Matrix.

Some features:

  • plot confusion matrix
  • plot normalized confusion matrix
  • class statistics
  • overall statistics

Here is an example:

In [1]: from pandas_ml import ConfusionMatrix
In [2]: import matplotlib.pyplot as plt

In [3]: y_test = ['business', 'business', 'business', 'business', 'business',
        'business', 'business', 'business', 'business', 'business',
        'business', 'business', 'business', 'business', 'business',
        'business', 'business', 'business', 'business', 'business']

In [4]: y_pred = ['health', 'business', 'business', 'business', 'business',
       'business', 'health', 'health', 'business', 'business', 'business',
       'business', 'business', 'business', 'business', 'business',
       'health', 'health', 'business', 'health']

In [5]: cm = ConfusionMatrix(y_test, y_pred)

In [6]: cm
Out[6]:
Predicted  business  health  __all__
Actual
business         14       6       20
health            0       0        0
__all__          14       6       20

In [7]: cm.plot()
Out[7]: <matplotlib.axes._subplots.AxesSubplot at 0x1093cf9b0>

In [8]: plt.show()

Plot confusion matrix

In [9]: cm.print_stats()
Confusion Matrix:

Predicted  business  health  __all__
Actual
business         14       6       20
health            0       0        0
__all__          14       6       20


Overall Statistics:

Accuracy: 0.7
95% CI: (0.45721081772371086, 0.88106840959427235)
No Information Rate: ToDo
P-Value [Acc > NIR]: 0.608009812201
Kappa: 0.0
Mcnemar's Test P-Value: ToDo


Class Statistics:

Classes                                 business health
Population                                    20     20
P: Condition positive                         20      0
N: Condition negative                          0     20
Test outcome positive                         14      6
Test outcome negative                          6     14
TP: True Positive                             14      0
TN: True Negative                              0     14
FP: False Positive                             0      6
FN: False Negative                             6      0
TPR: (Sensitivity, hit rate, recall)         0.7    NaN
TNR=SPC: (Specificity)                       NaN    0.7
PPV: Pos Pred Value (Precision)                1      0
NPV: Neg Pred Value                            0      1
FPR: False-out                               NaN    0.3
FDR: False Discovery Rate                      0      1
FNR: Miss Rate                               0.3    NaN
ACC: Accuracy                                0.7    0.7
F1 score                               0.8235294      0
MCC: Matthews correlation coefficient        NaN    NaN
Informedness                                 NaN    NaN
Markedness                                     0      0
Prevalence                                     1      0
LR+: Positive likelihood ratio               NaN    NaN
LR-: Negative likelihood ratio               NaN    NaN
DOR: Diagnostic odds ratio                   NaN    NaN
FOR: False omission rate                       1      0

Angularjs - ng-cloak/ng-show elements blink

As mentioned in the documentation, you should add a rule to your CSS to hide it based on the ng-cloak attribute:

[ng\:cloak], [ng-cloak], .ng-cloak {
    display: none;
}

We use similar tricks on the "Built with Angular" site, which you can view the source of on Github: https://github.com/angular/builtwith.angularjs.org

Hope that helps!

Big O, how do you calculate/approximate it?

I don't know how to programmatically solve this, but the first thing people do is that we sample the algorithm for certain patterns in the number of operations done, say 4n^2 + 2n + 1 we have 2 rules:

  1. If we have a sum of terms, the term with the largest growth rate is kept, with other terms omitted.
  2. If we have a product of several factors constant factors are omitted.

If we simplify f(x), where f(x) is the formula for number of operations done, (4n^2 + 2n + 1 explained above), we obtain the big-O value [O(n^2) in this case]. But this would have to account for Lagrange interpolation in the program, which may be hard to implement. And what if the real big-O value was O(2^n), and we might have something like O(x^n), so this algorithm probably wouldn't be programmable. But if someone proves me wrong, give me the code . . . .

Configuring so that pip install can work from github

If you want to use requirements.txt file, you will need git and something like the entry below to anonymously fetch the master branch in your requirements.txt.

For regular install:

git+git://github.com/celery/django-celery.git

For "editable" install:

-e git://github.com/celery/django-celery.git#egg=django-celery

Editable mode downloads the project's source code into ./src in the current directory. It allows pip freeze to output the correct github location of the package.

What does the term "Tuple" Mean in Relational Databases?

Most of the answers here are on the right track. However, a row is not a tuple. Tuples* are unordered sets of known values with names. Thus, the following tuples are the same thing (I'm using an imaginary tuple syntax since a relational tuple is largely a theoretical construct):

(x=1, y=2, z=3)
(z=3, y=2, x=1)
(y=2, z=3, x=1)

...assuming of course that x, y, and z are all integers. Also note that there is no such thing as a "duplicate" tuple. Thus, not only are the above equal, they're the same thing. Lastly, tuples can only contain known values (thus, no nulls).

A row** is an ordered set of known or unknown values with names (although they may be omitted). Therefore, the following comparisons return false in SQL:

(1, 2, 3) = (3, 2, 1)
(3, 1, 2) = (2, 1, 3)

Note that there are ways to "fake it" though. For example, consider this INSERT statement:

INSERT INTO point VALUES (1, 2, 3)

Assuming that x is first, y is second, and z is third, this query may be rewritten like this:

INSERT INTO point (x, y, z) VALUES (1, 2, 3)

Or this:

INSERT INTO point (y, z, x) VALUES (2, 3, 1)

...but all we're really doing is changing the ordering rather than removing it.

And also note that there may be unknown values as well. Thus, you may have rows with unknown values:

(1, 2, NULL) = (1, 2, NULL)

...but note that this comparison will always yield UNKNOWN. After all, how can you know whether two unknown values are equal?

And lastly, rows may be duplicated. In other words, (1, 2) and (1, 2) may compare to be equal, but that doesn't necessarily mean that they're the same thing.

If this is a subject that interests you, I'd highly recommend reading SQL and Relational Theory: How to Write Accurate SQL Code by CJ Date.

* Note that I'm talking about tuples as they exist in the relational model, which is a bit different from mathematics in general.

**And just in case you're wondering, just about everything in SQL is a row or table. Therefore, (1, 2) is a row, while VALUES (1, 2) is a table (with one row).

UPDATE: I've expanded a little bit on this answer in a blog post here.

Jquery: Checking to see if div contains text, then action

Here's a vanilla Javascript solution in 2020:

const fieldItem = document.querySelector('#field .field-item')
fieldItem.innerText === 'someText' ? fieldItem.classList.add('red') : '';

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

In my case the files VS coulnd't copy were those of the .Task project, so the problem was that I had a few scheduled tasks running locally. Once I stopped and disabled them, the copy problem disappeared.

How do you write multiline strings in Go?

Go and multiline strings

Using back ticks you can have multiline strings:

package main

import "fmt"

func main() {

    message := `This is a 
Multi-line Text String
Because it uses the raw-string back ticks 
instead of quotes.
`

    fmt.Printf("%s", message)
}

Instead of using either the double quote (“) or single quote symbols (‘), instead use back-ticks to define the start and end of the string. You can then wrap it across lines.

If you indent the string though, remember that the white space will count.

Please check the playground and do experiments with it.

How to correctly implement custom iterators and const_iterators?

Check this below code, it works

#define MAX_BYTE_RANGE 255

template <typename T>
class string
{
public:
    typedef char *pointer;
    typedef const char *const_pointer;
    typedef __gnu_cxx::__normal_iterator<pointer, string> iterator;
    typedef __gnu_cxx::__normal_iterator<const_pointer, string> const_iterator;

    string() : length(0)
    {
    }
    size_t size() const
    {
        return length;
    }
    void operator=(const_pointer value)
    {
        if (value == nullptr)
            throw std::invalid_argument("value cannot be null");
        auto count = strlen(value);
        if (count > 0)
            _M_copy(value, count);
    }
    void operator=(const string &value)
    {
        if (value.length != 0)
            _M_copy(value.buf, value.length);
    }
    iterator begin()
    {
        return iterator(buf);
    }
    iterator end()
    {
        return iterator(buf + length);
    }
    const_iterator begin() const
    {
        return const_iterator(buf);
    }
    const_iterator end() const
    {
        return const_iterator(buf + length);
    }
    const_pointer c_str() const
    {
        return buf;
    }
    ~string()
    {
    }

private:
    unsigned char length;
    T buf[MAX_BYTE_RANGE];

    void _M_copy(const_pointer value, size_t count)
    {
        memcpy(buf, value, count);
        length = count;
    }
};

how to run mysql in ubuntu through terminal

You seem to just have begun using mysql.

Simple answer: for now use

mysql -u root -p password

Password is usually root by default. You may use other usernames if you have created other user using create user in mysql. For details use "help, help manage accounts, help create users" etc. If you dont want your password to be shown in open just press return key after "-p" and you will be prompted for password next. Hope this resolves the issue.

Insert array into MySQL database with PHP

Maybe it will be to complex for this question but it surely do the job for you. I have created two classes to handle not only array insertion but also querying the database, updating and deleting files. "MySqliConnection" class is used to create only one instance of db connection (to prevent duplication of new objects). 

    <?php
    /**
     *
     * MySQLi database connection: only one connection is allowed
     */
    class MySqliConnection{
        public static $_instance;
        public $_connection;

        public function __construct($host, $user, $password, $database){
            $this->_connection = new MySQLi($host, $user, $password, $database);
            if (isset($mysqli->connect_error)) {
                echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") " . $mysqli->connect_error;
                echo $mysqli->host_info . "\n";
            }
        }

        /*
        * Gets instance of connection to database
        * @return (MySqliConnection) Object
        */
        public static function getInstance($host, $user, $password, $database){
            if(!self::$_instance){ 
                self::$_instance = new self($host, $user, $password, $database); //if no instance were created - new one will be initialize
            }
            return self::$_instance; //return already exsiting instance of the database connection
        }

        /*
        * Prevent database connection from bing copied while assignig the object to new wariable
        * @return (MySqliConnection) Object
        */
        public function getConnection(){
            return $this->_connection;
        }

        /*
        * Prevent database connection from bing copied/duplicated while assignig the object to new wariable
        * @return nothing
        */
        function __clone(){

        }
    }


    /*// CLASS USE EXAMPLE 
        $db = MySqliConnection::getInstance('localhost', 'root', '', 'sandbox');
        $mysqli = $db->getConnection();
        $sql_query = 'SELECT * FROM users;
            $this->lastQuery = $sql_query;
            $result = $mysqli->query($sql_query);
        while($row = $result->fetch_array(MYSQLI_ASSOC)){
            echo $row['ID'];
        }

    */

The second "TableManager" class is little bit more complex. It also make use of the MySqliConnection class which I posted above. So you would have to include both of them in your project. TableManager will allow you to easy make insertion updates and deletions. Class have separate placeholder for read and write. 

<?php

/*
* DEPENDENCIES:
* include 'class.MySqliConnection.inc'; //custom class
*
*/

class TableManager{

    private $lastQuery;
    private $lastInsertId;
    private $tableName;
    private $tableIdName;
    private $columnNames = array();
    private $lastResult = array();
    private $curentRow = array();
    private $newPost = array();

    /*
    * Class constructor 
    * [1] (string) $tableName // name of the table which you want to work with
    * [2] (string) $tableIdName // name of the ID field which will be used to delete and update records
    * @return void
    */
    function __construct($tableName, $tableIdName){
        $this->tableIdName = $tableIdName;
        $this->tableName = $tableName;
        $this->getColumnNames();
        $this->curentRow = $this->columnNames;
    }

public function getColumnNames(){
    $sql_query = 'SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE table_name = "'.$this->tableName.'"';
    $mysqli = $this->connection();
    $this->lastQuery = $sql_query;
    $result = $mysqli->query($sql_query);
    if (!$result) {
        throw new Exception("Database Error [{$this->database->errno}] {$this->database->error}");
    }
    while($row = $result->fetch_array(MYSQLI_ASSOC)){           
        $this->columnNames[$row['COLUMN_NAME']] = null;
    }
}

    /*
    * Used by a Constructor to set native parameters or virtual array curentRow of the class
    * [1] (array) $v
    * @return void
    */
    function setRowValues($v){

        if(!is_array($v)){
            $this->curentRow = $v;
            return true;    
        }
        foreach ($v as $a => $b) {
            $method = 'set'.ucfirst($a);
            if(is_callable(array($this, $method))){
                //if method is callable use setSomeFunction($k, $v) to filter the value
                $this->$method($b);
            }else{
                $this->curentRow[$a] = $b;
            }
        }

    }

    /*
    * Used by a constructor to set native parameters or virtual array curentRow of the class
    * [0]
    * @return void
    */
    function __toString(){
        var_dump($this);
    }

    /*
    * Query Database for information - Select column in table where column = somevalue
    * [1] (string) $column_name // name od a column
    * [2] (string) $quote_pos // searched value in a specified column
    * @return void
    */
    public function getRow($column_name = false, $quote_post = false){
        $mysqli = $this->connection();
        $quote_post = $mysqli->real_escape_string($quote_post);
        $this->tableName = $mysqli->real_escape_string($this->tableName);
        $column_name = $mysqli->real_escape_string($column_name);
        if($this->tableName && $column_name && $quote_post){
            $sql_query = 'SELECT * FROM '.$this->tableName.' WHERE '.$column_name.' = "'.$quote_post.'"';
            $this->lastQuery = $sql_query;
            $result = $mysqli->query($sql_query);
            if (!$result) {
                throw new Exception("Database Error [{$this->database->errno}] {$this->database->error}");
            }
            while($row = $result->fetch_array(MYSQLI_ASSOC)){
                $this->lastResult[$row['ID']] = $row;
                $this->setRowValues($row);
            }
        }
        if($this->tableName && $column_name && !$quote_post){
            $sql_query = 'SELECT '.$column_name.' FROM '.$this->tableName.'';
            $this->lastQuery = $sql_query;
            $result = $mysqli->query($sql_query);
            if (!$result) {
                throw new Exception("Database Error [{$this->database->errno}] {$this->database->error}");
            }
            while($row = $result->fetch_array(MYSQLI_ASSOC)){           
                $this->lastResult[] = $row;
                $this->setRowValues($row);
            }       
        }
        if($this->tableName && !$column_name && !$quote_post){
            $sql_query = 'SELECT * FROM '.$this->tableName.'';
            $this->lastQuery = $sql_query;
            $result = $mysqli->query($sql_query);
            if (!$result) {
                throw new Exception("Database Error [{$this->database->errno}] {$this->database->error}");
            }
            while($row = $result->fetch_array(MYSQLI_ASSOC)){           
                $this->lastResult[$row['ID']] = $row;
                $this->setRowValues($row);
            }       
        }
    }


    /*
    * Connection class gets instance of db connection or if not exsist creats one
    * [0]
    * @return $mysqli
    */
    private function connection(){
        $this->lastResult = "";
        $db = MySqliConnection::getInstance('localhost', 'root', '', 'sandbox');
        $mysqli = $db->getConnection();
        return $mysqli;
    }

    /*
    * ...
    * [1] (string) $getMe
    * @return void
    */
    function __get($getMe){
        if(isset($this->curentRow[$getMe])){
            return $this->curentRow[$getMe];
        }else{
            throw new Exception("Error Processing Request - No such a property in (array) $this->curentRow", 1);
        }

    }

    /*
    * ...
    * [2] (string) $setMe, (string) $value
    * @return void
    */
    function __set($setMe, $value){
        $temp = array($setMe=>$value);
        $this->setRowValues($temp);
    }

    /*
    * Dumps the object
    * [0] 
    * @return void
    */
    function dump(){
        echo "<hr>";
        var_dump($this);
        echo "<hr>";
    }

    /*
    * Sets Values for $this->newPost array which will be than inserted by insertNewPost() function
    * [1] (array) $newPost //array of avlue that will be inserted to $this->newPost
    * @return bolean
    */
    public function setNewRow($arr){

        if(!is_array($arr)){
            $this->newPost = $arr;
            return false;   
        }
        foreach ($arr as $k => $v) {
            if(array_key_exists($k, $this->columnNames)){
                $method = 'set'.ucfirst($k);
                if(is_callable(array($this, $method))){
                    if($this->$method($v) == false){ //if something go wrong
                        $this->newPost = array(); //empty the newPost array and return flase
                        throw new Exception("There was a problem in setting up New Post parameters. [Cleaning array]", 1);
                    }
                }else{
                    $this->newPost[$k] = $v;
                }
            }else{
                $this->newPost = array(); //empty the newPost array and return flase
                throw new Exception("The column does not exsist in this table. [Cleaning array]", 1);
            }
        }

    }


    /*
    * Inserts new post held in $this->newPost
    * [0]
    * @return bolean
    */
    public function insertNewRow(){
        // check if is set, is array and is not null
        if(isset($this->newPost) && !is_null($this->newPost) && is_array($this->newPost)){
            $mysqli = $this->connection();
            $count_lenght_of_array = count($this->newPost);

            // preper insert query
            $sql_query = 'INSERT INTO '.$this->tableName.' (';
            $i = 1;
            foreach ($this->newPost as $key => $value) {
                $sql_query .=$key;
                if ($i < $count_lenght_of_array) {
                    $sql_query .=', ';
                }

                $i++;
             } 

            $i = 1;  
            $sql_query .=') VALUES (';
            foreach ($this->newPost as $key => $value) {
                $sql_query .='"'.$value.'"';
                if ($i < $count_lenght_of_array) {
                    $sql_query .=', ';
                }

                $i++;
             }  

            $sql_query .=')';
            var_dump($sql_query);
            if($mysqli->query($sql_query)){
                $this->lastInsertId = $mysqli->insert_id;
                $this->lastQuery = $sql_query;
            }

            $this->getInsertedPost($this->lastInsertId);
        }
    }   

    /*
    * getInsertedPost function query the last inserted id and assigned it to the object.
    * [1] (integer) $id // last inserted id from insertNewRow fucntion
    * @return void
    */
    private function getInsertedPost($id){
        $mysqli = $this->connection();
        $sql_query = 'SELECT * FROM '.$this->tableName.' WHERE '.$this->tableIdName.' = "'.$id.'"';
        $result = $mysqli->query($sql_query);
        while($row = $result->fetch_array(MYSQLI_ASSOC)){
            $this->lastResult[$row['ID']] = $row;
            $this->setRowValues($row);
        }       
    }

    /*
    * getInsertedPost function query the last inserted id and assigned it to the object.
    * [0]
    * @return bolean // if deletion was successful return true
    */
    public function deleteLastInsertedPost(){
        $mysqli = $this->connection();
        $sql_query = 'DELETE FROM '.$this->tableName.' WHERE '.$this->tableIdName.' = '.$this->lastInsertId.'';
        $result = $mysqli->query($sql_query);
        if($result){
            $this->lastResult[$this->lastInsertId] = "deleted";
            return true;
        }else{
            throw new Exception("We could not delete last inserted row by ID [{$mysqli->errno}] {$mysqli->error}");

        }
        var_dump($sql_query);       
    }

    /*
    * deleteRow function delete the row with from a table based on a passed id
    * [1] (integer) $id // id of the table row to be delated
    * @return bolean // if deletion was successful return true
    */
    public function deleteRow($id){
        $mysqli = $this->connection();
        $sql_query = 'DELETE FROM '.$this->tableName.' WHERE '.$this->tableIdName.' = '.$id.'';
        $result = $mysqli->query($sql_query);
        if($result){
            $this->lastResult[$this->lastInsertId] = "deleted";
            return true;
        }else{
            return false;
        }
        var_dump($sql_query);       
    }

    /*
    * deleteAllRows function deletes all rows from a table
    * [0]
    * @return bolean // if deletion was successful return true
    */
    public function deleteAllRows(){
        $mysqli = $this->connection();
        $sql_query = 'DELETE FROM '.$this->tableName.'';
        $result = $mysqli->query($sql_query);
        if($result){
            return true;
        }else{
            return false;
        }       
    }

    /*
    * updateRow function updates all values to object values in a row with id
    * [1] (integer) $id
    * @return bolean // if deletion was successful return true
    */
    public function updateRow($update_where = false){
        $id = $this->curentRow[$this->tableIdName];
        $mysqli = $this->connection();
        $updateMe = $this->curentRow;
        unset($updateMe[$this->tableIdName]);
        $count_lenght_of_array = count($updateMe);
        // preper insert query
        $sql_query = 'UPDATE '.$this->tableName.' SET ';
        $i = 1;
        foreach ($updateMe as $k => $v) {
            $sql_query .= $k.' = "'.$v.'"';
            if ($i < $count_lenght_of_array) {
                $sql_query .=', ';
            }

            $i++;
         }
        if($update_where == false){ 
            //update row only for this object id
            $sql_query .=' WHERE '.$this->tableIdName.' = '.$this->curentRow[$this->tableIdName].'';
        }else{
            //add your custom update where query
            $sql_query .=' WHERE '.$update_where.'';
        }

        var_dump($sql_query);
        if($mysqli->query($sql_query)){
            $this->lastQuery = $sql_query;
        }
        $result = $mysqli->query($sql_query);
        if($result){
            return true;
        }else{
            return false;
        }       
    }

}



/*TO DO

1 insertPost(X, X) write function to isert data and in to database;
2 get better query system and display data from database;
3 write function that displays data of a object not databsae;
object should be precise and alocate only one instance of the post at a time. 
// Updating the Posts to curent object $this->curentRow values
->updatePost();

// Deleting the curent post by ID

// Add new row to database

*/





/*
USE EXAMPLE
$Post = new TableManager("post_table", "ID"); // New Object

// Getting posts from the database based on pased in paramerters
$Post->getRow('post_name', 'SOME POST TITLE WHICH IS IN DATABASE' );
$Post->getRow('post_name');
$Post->getRow();



MAGIC GET will read current object  $this->curentRow parameter values by refering to its key as in a varible name
echo $Post->ID.
echo $Post->post_name;
echo $Post->post_description;
echo $Post->post_author;


$Task = new TableManager("table_name", "table_ID_name"); // creating new TableManager object

$addTask = array( //just an array [colum_name] => [values]
    'task_name' => 'New Post',
    'description' => 'New Description Post',
    'person' => 'New Author',
    );
$Task->setNewRow($addTask); //preper new values for insertion to table
$Task->getRow('ID', '12'); //load value from table to object

$Task->insertNewRow(); //inserts new row
$Task->dump(); //diplays object properities

$Task->person = "John"; //magic __set() method will look for setPerson(x,y) method firs if non found will assign value as it is. 
$Task->description = "John Doe is a funny guy"; //magic __set() again
$Task->task_name = "John chellange"; //magic __set() again

$test = ($Task->updateRow("ID = 5")) ? "WORKS FINE" : "ERROR"; //update cutom row with object values
echo $test;
$test = ($Task->updateRow()) ? "WORKS FINE" : "ERROR"; //update curent data loaded in object
echo $test;
*/

Static way to get 'Context' in Android?

You can use the following:

MainActivity.this.getApplicationContext();

MainActivity.java:

...
public class MainActivity ... {
    static MainActivity ma;
...
    public void onCreate(Bundle b) {
         super...
         ma=this;
         ...

Any other class:

public ...
    public ANY_METHOD... {
         Context c = MainActivity.ma.getApplicationContext();

Python3 integer division

Try this:

a = 1
b = 2
int_div  = a // b

Is there a way to perform "if" in python's lambda

Probably the worst python line I've written so far: 

f = lambda x: sys.stdout.write(["2\n",][2*(x==2)-2])

If x == 2 you print,

if x != 2 you raise.

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

Use:

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

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

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

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

"An attempt was made to load a program with an incorrect format" even when the platforms are the same

If you try to run 32-bit applications on IIS 7 (and/or 64-bit OS machine), you will get the same error. So, from the IIS 7, right click on the applications' application pool and go to "advanced settings" and change "Enable 32-Bit Applications" to "TRUE".

Restart your website and it should work.

enter image description here

SQL: capitalize first letter only

Are you asking for renaming column itself or capitalise the data inside column? If its data you've to change, then use this:

UPDATE [yourtable]
SET word=UPPER(LEFT(word,1))+LOWER(SUBSTRING(word,2,LEN(word)))

If you just wanted to change it only for displaying and do not need the actual data in table to change:

SELECT UPPER(LEFT(word,1))+LOWER(SUBSTRING(word,2,LEN(word))) FROM [yourtable]

Hope this helps.

EDIT: I realised about the '-' so here is my attempt to solve this problem in a function.

CREATE FUNCTION [dbo].[CapitalizeFirstLetter]
(
--string need to format
@string VARCHAR(200)--increase the variable size depending on your needs.
)
RETURNS VARCHAR(200)
AS

BEGIN
--Declare Variables
DECLARE @Index INT,
@ResultString VARCHAR(200)--result string size should equal to the @string variable size
--Initialize the variables
SET @Index = 1
SET @ResultString = ''
--Run the Loop until END of the string

WHILE (@Index <LEN(@string)+1)
BEGIN
IF (@Index = 1)--first letter of the string
BEGIN
--make the first letter capital
SET @ResultString =
@ResultString + UPPER(SUBSTRING(@string, @Index, 1))
SET @Index = @Index+ 1--increase the index
END

-- IF the previous character is space or '-' or next character is '-'

ELSE IF ((SUBSTRING(@string, @Index-1, 1) =' 'or SUBSTRING(@string, @Index-1, 1) ='-' or SUBSTRING(@string, @Index+1, 1) ='-') and @Index+1 <> LEN(@string))
BEGIN
--make the letter capital
SET
@ResultString = @ResultString + UPPER(SUBSTRING(@string,@Index, 1))
SET
@Index = @Index +1--increase the index
END
ELSE-- all others
BEGIN
-- make the letter simple
SET
@ResultString = @ResultString + LOWER(SUBSTRING(@string,@Index, 1))
SET
@Index = @Index +1--incerase the index
END
END--END of the loop

IF (@@ERROR
<> 0)-- any error occur return the sEND string
BEGIN
SET
@ResultString = @string
END
-- IF no error found return the new string
RETURN @ResultString
END

So then the code would be:

UPDATE [yourtable]
SET word=dbo.CapitalizeFirstLetter([STRING TO GO HERE])

How to pause a vbscript execution?

Script snip below creates a pause sub that displayes the pause text in a string and waits for the Enter key. z can be anything. Great if multilple user intervention required pauses are needed. I just keep it in my standard script template.

Pause("Press Enter to continue")

Sub Pause(strPause)
     WScript.Echo (strPause)
     z = WScript.StdIn.Read(1)
End Sub

When should I use a List vs a LinkedList

I do agree with most of the point made above. And I also agree that List looks like a more obvious choice in most of the cases.

But, I just want to add that there are many instance where LinkedList are far better choice than List for better efficiency.

  1. Suppose you are traversing through the elements and you want to perform lot of insertions/deletion; LinkedList does it in linear O(n) time, whereas List does it in quadratic O(n^2) time.
  2. Suppose you want to access bigger objects again and again, LinkedList become very more useful.
  3. Deque() and queue() are better implemented using LinkedList.
  4. Increasing the size of LinkedList is much easier and better once you are dealing with many and bigger objects.

Hope someone would find these comments useful.

Converting Columns into rows with their respective data in sql server

i solved the query this way

SELECT
    ca.ID, ca.[Name]
FROM [Emp2]
CROSS APPLY (
      Values
         ('ID' , cast(ID as varchar)),
         ('[Name]' , Name)

  ) as CA (ID, Name)

output look like

  ID     Name
------ --------------------------------------------------
ID     1
[Name] Joy
ID     2
[Name] jean
ID     4
[Name] paul

MAC addresses in JavaScript

Nope. The reason ActiveX can do it is because ActiveX is a little application that runs on the client's machine.

I would imagine access to such information via JavaScript would be a security vulnerability.

How do I make a https post in Node Js without any third party module?

For example, like this:

const querystring = require('querystring');
const https = require('https');

var postData = querystring.stringify({
    'msg' : 'Hello World!'
});

var options = {
  hostname: 'posttestserver.com',
  port: 443,
  path: '/post.php',
  method: 'POST',
  headers: {
       'Content-Type': 'application/x-www-form-urlencoded',
       'Content-Length': postData.length
     }
};

var req = https.request(options, (res) => {
  console.log('statusCode:', res.statusCode);
  console.log('headers:', res.headers);

  res.on('data', (d) => {
    process.stdout.write(d);
  });
});

req.on('error', (e) => {
  console.error(e);
});

req.write(postData);
req.end();

How to control the width of select tag?

You've simply got it backwards. Specifying a minimum width would make the select menu always be at least that width, so it will continue expanding to 90% no matter what the window size is, also being at least the size of its longest option.

You need to use max-width instead. This way, it will let the select menu expand to its longest option, but if that expands past your set maximum of 90% width, crunch it down to that width.

DropDownList's SelectedIndexChanged event not firing

Instead of what you have written, you can write it directly in the SelectedIndexChanged event of the dropdownlist control, e.g.

protected void ddlleavetype_SelectedIndexChanged(object sender, EventArgs e)
{
 //code goes here
}

How do I convert a Python program to a runnable .exe Windows program?

I've used py2exe in the past and have been very happy with it. I didn't particularly enjoy using cx-freeze as much, though

How to use querySelectorAll only for elements that have a specific attribute set?

Extra Tips:

Multiple "nots", input that is NOT hidden and NOT disabled:

:not([type="hidden"]):not([disabled])

Also did you know you can do this:

node.parentNode.querySelectorAll('div');

This is equivelent to jQuery's:

$(node).parent().find('div');

Which will effectively find all divs in "node" and below recursively, HOT DAMN!

How do I avoid the specification of the username and password at every git push?

Wire your git client to your OS credential store. For example in Windows you bind the credential helper to wincred:

git config --global credential.helper wincred

Is there a way to skip password typing when using https:// on GitHub?

Where is the documentation for the values() method of Enum?

The method is implicitly defined (i.e. generated by the compiler).

From the JLS:

In addition, if E is the name of an enum type, then that type has the following implicitly declared static methods:

/**
* Returns an array containing the constants of this enum 
* type, in the order they're declared.  This method may be
* used to iterate over the constants as follows:
*
*    for(E c : E.values())
*        System.out.println(c);
*
* @return an array containing the constants of this enum 
* type, in the order they're declared
*/
public static E[] values();

/**
* Returns the enum constant of this type with the specified
* name.
* The string must match exactly an identifier used to declare
* an enum constant in this type.  (Extraneous whitespace 
* characters are not permitted.)
* 
* @return the enum constant with the specified name
* @throws IllegalArgumentException if this enum type has no
* constant with the specified name
*/
public static E valueOf(String name);

Why do abstract classes in Java have constructors?

I guess root of this question is that people believe that a call to a constructor creates the object. That is not the case. Java nowhere claims that a constructor call creates an object. It just does what we want constructor to do, like initialising some fields..that's all. So an abstract class's constructor being called doesn't mean that its object is created.

Autoreload of modules in IPython

REVISED - please see Andrew_1510's answer below, as IPython has been updated.

...

It was a bit hard figure out how to get there from a dusty bug report, but:

It ships with IPython now!

import ipy_autoreload
%autoreload 2
%aimport your_mod

# %autoreload? for help

... then every time you call your_mod.dwim(), it'll pick up the latest version.

In Excel how to get the left 5 characters of each cell in a specified column and put them into a new column

1) Put =Left(E1,5) in F1

2) Copy F1, then select entire F column and paste.

MySQL string replace

You can simply use replace() function,

with where clause-

update tabelName set columnName=REPLACE(columnName,'from','to') where condition;

without where clause-

update tabelName set columnName=REPLACE(columnName,'from','to');

Note: The above query if for update records directly in table, if you want on select query and the data should not be affected in table then can use the following query-

select REPLACE(columnName,'from','to') as updateRecord;

PHP Array to CSV

I know this is old, I had a case where I needed the array key to be included in the CSV also, so I updated the script by Jesse Q to do that. I used a string as output, as implode can't add new line (new line is something I added, and should really be there).

Please note, this only works with single value arrays (key, value). but could easily be updated to handle multi-dimensional (key, array()).

function arrayToCsv( array &$fields, $delimiter = ',', $enclosure = '"', $encloseAll = false, $nullToMysqlNull = false ) {
    $delimiter_esc = preg_quote($delimiter, '/');
    $enclosure_esc = preg_quote($enclosure, '/');

    $output = '';
    foreach ( $fields as $key => $field ) {
        if ($field === null && $nullToMysqlNull) {
            $output = '';
            continue;
        }

        // Enclose fields containing $delimiter, $enclosure or whitespace
        if ( $encloseAll || preg_match( "/(?:${delimiter_esc}|${enclosure_esc}|\s)/", $field ) ) {
            $output .= $key;
            $output .= $delimiter;
            $output .= $enclosure . str_replace($enclosure, $enclosure . $enclosure,     $field) . $enclosure;
            $output .= PHP_EOL;
        }
        else {
            $output .= $key;
            $output .= $delimiter;
            $output .= $field;
            $output .= PHP_EOL;
        }
    }

    return  $output ;
}

Oracle JDBC ojdbc6 Jar as a Maven Dependency

After executing

mvn install:install-file -DgroupId=com.oracle -DartifactId=ojdbc6 -Dversion=11.2.0.3 -Dpackaging=jar -Dfile=ojdbc6.jar -DgeneratePom=true

check your .m2 repository folder (/com/oracle/ojdbc6/11.2.0.3) to see if ojdbc6.jar exists. If not check your maven repository settings under $M2_HOME/conf/settings.xml

SQL Server: Database stuck in "Restoring" state

OK, I have similar problem and exactly as it was in case of Pauk, it was caused by the server running out of disk space while restoring and so caused a permanent restoring state. How to end this state without stopping SQL Server services?

I have found a solution :)

Drop database *dbname*

WPF Add a Border to a TextBlock

A TextBlock does not actually inherit from Control so it does not have properties that you would generally associate with a Control. Your best bet for adding a border in a style is to replace the TextBlock with a Label

See this link for more on the differences between a TextBlock and other Controls

How to generate all permutations of a list?

Anyway we could use sympy library , also support for multiset permutations

import sympy
from sympy.utilities.iterables import multiset_permutations
t = [1,2,3]
p = list(multiset_permutations(t))
print(p)

# [[1, 2, 3], [1, 3, 2], [2, 1, 3], [2, 3, 1], [3, 1, 2], [3, 2, 1]]

Answer is highly inspired by Get all permutations of a numpy array

How to get the last char of a string in PHP?

As of PHP 7.1.0, negative string offsets are also supported. So, if you keep up with the times, you can access the last character in the string like this:

$str[-1]

DEMO

At the request of a @mickmackusa, I supplement my answer with possible ways of application:

<?php

$str='abcdef';
var_dump($str[-2]); // => string(1) "e"

$str[-3]='.';
var_dump($str);     // => string(6) "abc.ef"

var_dump(isset($str[-4]));  // => bool(true)

var_dump(isset($str[-10])); // => bool(false)

ROW_NUMBER() in MySQL

I want the row with the single highest col3 for each (col1, col2) pair.

That's a groupwise maximum, one of the most commonly-asked SQL questions (since it seems like it should be easy, but actually it kind of isn't).

I often plump for a null-self-join:

SELECT t0.col3
FROM table AS t0
LEFT JOIN table AS t1 ON t0.col1=t1.col1 AND t0.col2=t1.col2 AND t1.col3>t0.col3
WHERE t1.col1 IS NULL;

“Get the rows in the table for which no other row with matching col1,col2 has a higher col3.” (You will notice this and most other groupwise-maximum solutions will return multiple rows if more than one row has the same col1,col2,col3. If that's a problem you may need some post-processing.)

ToggleClass animate jQuery?

You can simply use CSS transitions, see this fiddle

.on {
color:#fff;
transition:all 1s;
}

.off{
color:#000;
transition:all 1s;
}

Why is processing a sorted array faster than processing an unsorted array?

You are a victim of branch prediction fail.

What is Branch Prediction?

Consider a railroad junction:

Image showing a railroad junction Image by Mecanismo, via Wikimedia Commons. Used under the CC-By-SA 3.0 license.

Now for the sake of argument, suppose this is back in the 1800s - before long distance or radio communication.

You are the operator of a junction and you hear a train coming. You have no idea which way it is supposed to go. You stop the train to ask the driver which direction they want. And then you set the switch appropriately.

Trains are heavy and have a lot of inertia. So they take forever to start up and slow down.

Is there a better way? You guess which direction the train will go!

  • If you guessed right, it continues on.
  • If you guessed wrong, the captain will stop, back up, and yell at you to flip the switch. Then it can restart down the other path.

If you guess right every time, the train will never have to stop.
If you guess wrong too often, the train will spend a lot of time stopping, backing up, and restarting.

Consider an if-statement: At the processor level, it is a branch instruction:

Screenshot of compiled code containing an if statement

You are a processor and you see a branch. You have no idea which way it will go. What do you do? You halt execution and wait until the previous instructions are complete. Then you continue down the correct path.

Modern processors are complicated and have long pipelines. So they take forever to "warm up" and "slow down".

Is there a better way? You guess which direction the branch will go!

  • If you guessed right, you continue executing.
  • If you guessed wrong, you need to flush the pipeline and roll back to the branch. Then you can restart down the other path.

If you guess right every time, the execution will never have to stop.
If you guess wrong too often, you spend a lot of time stalling, rolling back, and restarting.

This is branch prediction. I admit it's not the best analogy since the train could just signal the direction with a flag. But in computers, the processor doesn't know which direction a branch will go until the last moment.

So how would you strategically guess to minimize the number of times that the train must back up and go down the other path? You look at the past history! If the train goes left 99% of the time, then you guess left. If it alternates, then you alternate your guesses. If it goes one way every three times, you guess the same...

In other words, you try to identify a pattern and follow it. This is more or less how branch predictors work.

Most applications have well-behaved branches. So modern branch predictors will typically achieve >90% hit rates. But when faced with unpredictable branches with no recognizable patterns, branch predictors are virtually useless.

Further reading: "Branch predictor" article on Wikipedia.

As hinted from above, the culprit is this if-statement:

if (data[c] >= 128)
    sum += data[c];

Notice that the data is evenly distributed between 0 and 255. When the data is sorted, roughly the first half of the iterations will not enter the if-statement. After that, they will all enter the if-statement.

This is very friendly to the branch predictor since the branch consecutively goes the same direction many times. Even a simple saturating counter will correctly predict the branch except for the few iterations after it switches direction.

Quick visualization:

T = branch taken
N = branch not taken

data[] = 0, 1, 2, 3, 4, ... 126, 127, 128, 129, 130, ... 250, 251, 252, ...
branch = N  N  N  N  N  ...   N    N    T    T    T  ...   T    T    T  ...

       = NNNNNNNNNNNN ... NNNNNNNTTTTTTTTT ... TTTTTTTTTT  (easy to predict)

However, when the data is completely random, the branch predictor is rendered useless, because it can't predict random data. Thus there will probably be around 50% misprediction (no better than random guessing).

data[] = 226, 185, 125, 158, 198, 144, 217, 79, 202, 118,  14, 150, 177, 182, ...
branch =   T,   T,   N,   T,   T,   T,   T,  N,   T,   N,   N,   T,   T,   T  ...

       = TTNTTTTNTNNTTT ...   (completely random - impossible to predict)

So what can be done?

If the compiler isn't able to optimize the branch into a conditional move, you can try some hacks if you are willing to sacrifice readability for performance.

Replace:

if (data[c] >= 128)
    sum += data[c];

with:

int t = (data[c] - 128) >> 31;
sum += ~t & data[c];

This eliminates the branch and replaces it with some bitwise operations.

(Note that this hack is not strictly equivalent to the original if-statement. But in this case, it's valid for all the input values of data[].)

Benchmarks: Core i7 920 @ 3.5 GHz

C++ - Visual Studio 2010 - x64 Release

Scenario Time (seconds)
Branching - Random data 11.777
Branching - Sorted data 2.352
Branchless - Random data 2.564
Branchless - Sorted data 2.587

Java - NetBeans 7.1.1 JDK 7 - x64

Scenario Time (seconds)
Branching - Random data 10.93293813
Branching - Sorted data 5.643797077
Branchless - Random data 3.113581453
Branchless - Sorted data 3.186068823

Observations:

  • With the Branch: There is a huge difference between the sorted and unsorted data.
  • With the Hack: There is no difference between sorted and unsorted data.
  • In the C++ case, the hack is actually a tad slower than with the branch when the data is sorted.

A general rule of thumb is to avoid data-dependent branching in critical loops (such as in this example).

Update:

  • GCC 4.6.1 with -O3 or -ftree-vectorize on x64 is able to generate a conditional move. So there is no difference between the sorted and unsorted data - both are fast.

    (Or somewhat fast: for the already-sorted case, cmov can be slower especially if GCC puts it on the critical path instead of just add, especially on Intel before Broadwell where cmov has 2 cycle latency: gcc optimization flag -O3 makes code slower than -O2)

  • VC++ 2010 is unable to generate conditional moves for this branch even under /Ox.

  • Intel C++ Compiler (ICC) 11 does something miraculous. It interchanges the two loops, thereby hoisting the unpredictable branch to the outer loop. So not only is it immune to the mispredictions, it is also twice as fast as whatever VC++ and GCC can generate! In other words, ICC took advantage of the test-loop to defeat the benchmark...

  • If you give the Intel compiler the branchless code, it just out-right vectorizes it... and is just as fast as with the branch (with the loop interchange).

This goes to show that even mature modern compilers can vary wildly in their ability to optimize code...

How do I specify the JDK for a GlassFish domain?

According to the GF Administration Guide:

For a valid JVM installation, locations are checked in the following order: a. domain.xml (java-home inside java-config) b. asenv.conf (setting AS_JAVA="path to java home")

I had to add both these settings to make it work. Otherwise 'asadmin stop-domain domain1' wouldn't work. I guess that GF uses a. and asadmin uses b.

(On Windows: b. asenv.bat)

How to make a pure css based dropdown menu?

You don't have to always use ul elements to achieve that, you can use other elements too as seen below. Here there are 2 examples, one using div and one using select.

This examples demonstrates the basic functionality, but can be extended/enriched more. It is tested in linux only (iceweasel and chrome).

<!DOCTYPE html>
<html>
<head>
<meta charset='UTF-8'>
<style>
.drop_container
{
  position:relative;
  float:left;
}
.always_visible
{
  background-color:#FAFAFA;
  color:#333333;
  font-weight:bold;
  cursor:pointer;
  border:2px silver solid;
  margin:0px;
  margin-right:5px;
  font-size:14px;
  font-family:"Times New Roman", Times, serif;
}
.always_visible:hover + .hidden_container
{
  display:block;
  position:absolute;
  color:green;
}
.hidden_container
{
  display:none;
  border:1px gray solid;
  left:0px;
  background-color:#FAFAFA;
  padding:5px;
  z-index:1;
}
.hidden_container:hover
{
  display:block;
  position:absolute;
}
.link
{
  color:blue;
  white-space:nowrap;
  margin:3px;
  display:block;
}
.link:hover
{
  color:white;
  background-color:blue;
}
.line_1
{
  width:800px;
  border:1px tomato solid;
  padding:5px;
}
</style>      
</head>

<body>

<div class="line_1">
<div class="drop_container">
  <select class="always_visible" disabled><option>Select</option></select>
  <div class="hidden_container">
  <a href="http://www.google.gr" class="link">Option_ 1</a>
  <a href="http://www.google.gr" class="link">Option__ 2</a>
  <a href="http://www.google.gr" class="link">Option___ 3</a>
  <a href="http://www.google.gr" class="link">Option____ 4</a>
  </div>
</div>
<div class="drop_container">
  <select class="always_visible" disabled><option>Select</option></select>
  <div class="hidden_container">
  <a href="http://www.google.gr" class="link">____1</a>
  <a href="http://www.google.gr" class="link">___2</a>
  <a href="http://www.google.gr" class="link">__3</a>
  <a href="http://www.google.gr" class="link">_4</a>
  </div>
</div>
<div style="clear:both;"></div>
</div>

<br>

<div class="line_1">
 <div class="drop_container">
  <div class="always_visible">Select___</div>
  <div class="hidden_container">
  <a href="http://www.google.gr" class="link">Option_ 1</a>
  <a href="http://www.google.gr" class="link">Option__ 2</a>
  <a href="http://www.google.gr" class="link">Option___ 3</a>
  <a href="http://www.google.gr" class="link">Option____ 4</a>
  </div>
</div>
 <div class="drop_container">
  <div class="always_visible">Select___</div>
  <div class="hidden_container">
  <a href="http://www.google.gr" class="link">Option_ 1</a>
  <a href="http://www.google.gr" class="link">Option__ 2</a>
  <a href="http://www.google.gr" class="link">Option___ 3</a>
  <a href="http://www.google.gr" class="link">Option____ 4</a>
  </div>
</div>
<div style="clear:both;"></div>
</div>

</body>
</html>

When is JavaScript synchronous?

"I have been under the impression for that JavaScript was always asynchronous"

You can use JavaScript in a synchronous way, or an asynchronous way. In fact JavaScript has really good asynchronous support. For example I might have code that requires a database request. I can then run other code, not dependent on that request, while I wait for that request to complete. This asynchronous coding is supported with promises, async/await, etc. But if you don't need a nice way to handle long waits then just use JS synchronously.

What do we mean by 'asynchronous'. Well it does not mean multi-threaded, but rather describes a non-dependent relationship. Check out this image from this popular answer:

         A-Start ------------------------------------------ A-End   
           | B-Start -----------------------------------------|--- B-End   
           |    |      C-Start ------------------- C-End      |      |   
           |    |       |                           |         |      |
           V    V       V                           V         V      V      
1 thread->|<-A-|<--B---|<-C-|-A-|-C-|--A--|-B-|--C-->|---A---->|--B-->|

We see that a single threaded application can have async behavior. The work in function A is not dependent on function B completing, and so while function A began before function B, function A is able to complete at a later time and on the same thread.

So, just because JavaScript executes one command at a time, on a single thread, it does not then follow that JavaScript can only be used as a synchronous language.

"Is there a good reference anywhere about when it will be synchronous and when it will be asynchronous"

I'm wondering if this is the heart of your question. I take it that you mean how do you know if some code you are calling is async or sync. That is, will the rest of your code run off and do something while you wait for some result? Your first check should be the documentation for whichever library you are using. Node methods, for example, have clear names like readFileSync. If the documentation is no good there is a lot of help here on SO. EG:

How to know if a function is async?

How to make jQuery UI nav menu horizontal?

I know this is an old thread but I was digging into the jQuery UI source code and built upon Rowan's answer which was closer to what I had been looking for. Only I needed the carrots as I felt it was important to have a visual indicator of possible submenus. From looking at the source code (both .js and .css) I came up with this that allows the carrot be visiable without messing with design (height) and also alowing menu to appear vertical below the parent item.

In the jquery-ui.js do a search to find $.widget( "ui.menu") and change postition to: 

position: {
my: "center top",
at: "center bottom"
}

And in your css add: 

#nav > .ui-menu:after {
    content: ".";
    display: block;
    clear: both;
    visibility: hidden;
    line-height: 0;
    height: 0;
}

#nav > .ui-menu > .ui-menu-item {
    display: inline-block;
    float: left;

    margin: 0;
    padding: 3px;

    width: auto;
}

.ui-menu .ui-menu-item a {
    padding: 0;
}

.ui-menu .ui-menu-icon{
    position: relative;
    left: 1px;
    top: 6px;
}

End Result will be a jQuery UI Menu horizontal with sub menus being displayed veriticaly below the parent menu item.

JavaFX "Location is required." even though it is in the same package

I've seen this error a few times now. So often that I wrote a small project, called "Simple" with a Netbeans Maven FXML application template just to go back to as a kind of 'reference model' when things go askew. For testing, I use something like this:

    String sceneFile = "/fxml/main.fxml";
    Parent root = null;
    URL    url  = null;
    try
    {
        url  = getClass().getResource( sceneFile );
        root = FXMLLoader.load( url );
        System.out.println( "  fxmlResource = " + sceneFile );
    }
    catch ( Exception ex )
    {
        System.out.println( "Exception on FXMLLoader.load()" );
        System.out.println( "  * url: " + url );
        System.out.println( "  * " + ex );
        System.out.println( "    ----------------------------------------\n" );
        throw ex;
    }

When you run that snippet and the load fails, you should see a reason, or at least a message from the FXMLLoader. Since it's a test, I throw the exception. You don't want to continue.

Things to note. This is a maven project so the resources will be relative to the resources folder, hence:

  • "/fxml/main.fxml".
  • The leading slash is required.

  • The resource passed to the FXMLLoader is case-sensitive:

    // If you load "main.fxml" and your file is called: "Main.fxml"
// You will will see the message ...

java.lang.NullPointerException: Location is required.

  • If you get past that "location is required" issue, then you may have a problem in the FXML

    // Something like this: // javafx.fxml.LoadException: file:/D:/sandbox/javafx/app_examples/person/target/person-00.00.01-SNAPSHOT.jar!/fxml/tableWithDetails.fxml:13

Will mean that there's a problem on Line 13, in the file, per:

  • tableWithDetails.fxml :13

In the message. At this point you need to read the FXML and see if you can spot the problem. You could try some of the tips in the related question.

For this problem, my opinion is that the file name was proper case: "Main.fxml". When the file was moved the name was probably changed or the string retyped. Good luck.

Related:

How to convert an address into a Google Maps Link (NOT MAP)

How about this?

https://maps.google.com/?q=1200 Pennsylvania Ave SE, Washington, District of Columbia, 20003

https://maps.google.com/?q=term

If you have lat-long then use below URL

https://maps.google.com/?ll=latitude,longitude

Example: maps.google.com/?ll=38.882147,-76.99017

UPDATE

As of year 2017, Google now has an official way to create cross-platform Google Maps URLs:

https://developers.google.com/maps/documentation/urls/guide

You can use links like 

https://www.google.com/maps/search/?api=1&query=1200%20Pennsylvania%20Ave%20SE%2C%20Washington%2C%20District%20of%20Columbia%2C%2020003

eclipse stuck when building workspace

I have this problem whe I have too much maven projects open at once. What I tend to do is:

  • Restart eclipse (sometimes I need to kill eclipse)
  • Disable automatic build immediatly (project > uncheck Build automatically)
  • Right click the project(s) I want to have rebuild
  • Close unrelated projects
  • Re-enable automatic build

This enables a functioning rebuild in 99% off the cases in my workspace.

API pagination best practices

If you've got pagination you also sort the data by some key. Why not let API clients include the key of the last element of the previously returned collection in the URL and add a WHERE clause to your SQL query (or something equivalent, if you're not using SQL) so that it returns only those elements for which the key is greater than this value?

Dynamic height for DIV

Set both to auto:

height: auto;
width: auto;

Making it:

#products
{
    height: auto;
    width: auto;
    padding:5px; margin-bottom:8px;
    border: 1px solid #EFEFEF;
}

Read input from console in Ruby?

If you want to make interactive console:

#!/usr/bin/env ruby

require "readline"
addends = []
while addend_string = Readline.readline("> ", true)
  addends << addend_string.to_i
  puts "#{addends.join(' + ')} = #{addends.sum}"
end

Usage (assuming you put above snippet into summator file in current directory):

chmod +x summator
./summator
> 1
1 = 1
> 2
1 + 2 = 3

Use Ctrl + D to exit

How to "git show" a merge commit with combined diff output even when every changed file agrees with one of the parents?

A better solution (mentioned by @KrisNuttycombe):

git diff fc17405...ee2de56

for the merge commit:

commit 0e1329e551a5700614a2a34d8101e92fd9f2cad6 (HEAD, master)
Merge: fc17405 ee2de56
Author: Tilman Vogel <email@email>
Date:   Tue Feb 22 00:27:17 2011 +0100

to show all of the changes on ee2de56 that are reachable from commits on fc17405. Note the order of the commit hashes - it's the same as shown in the merge info: Merge: fc17405 ee2de56

Also note the 3 dots ... instead of two!

For a list of changed files, you can use:

git diff fc17405...ee2de56 --name-only

Twig ternary operator, Shorthand if-then-else

You can use shorthand syntax as of Twig 1.12.0

{{ foo ?: 'no' }} is the same as {{ foo ? foo : 'no' }}
{{ foo ? 'yes' }} is the same as {{ foo ? 'yes' : '' }}

How to do joins in LINQ on multiple fields in single join

 
var result = from x in entity1
             join y in entity2
             on new { X1= x.field1, X2= x.field2 } equals new { X1=y.field1, X2= y.field2 }

You need to do this, if the column names are different in two entities.

jump to line X in nano editor

According to section 2.2 of the manual, you can use the Escape key pressed twice in place of the CTRL key. This allowed me to use Nano's key combination for GO TO LINE when running Nano on a Jupyter/ JupyterHub and accessing through my browser. The normal key combination was getting 'swallowed' as the manual warns about can more often happen with the ALT key on some systems, and which can be replaced by one press of the ESCAPE key.
So for jump to line it was ESCAPE pressed twice, followed by shift key + dash key.

Rendering HTML inside textarea

An addendum to this. You can use character entities (such as changing <div> to &lt;div&gt;) and it will render in the textarea. But when it is saved, the value of the textarea is the text as rendered. So you don't need to de-encode. I just tested this across browsers (ie back to 11).

error "Could not get BatchedBridge, make sure your bundle is packaged properly" on start of app

Try this command in terminal and then reload. It worked for me

adb reverse tcp:8081 tcp:8081

how to "execute" make file

You don't tend to execute the make file itself, rather you execute make, giving it the make file as an argument:

make -f pax.mk

If your make file is actually one of the standard names (like makefile or Makefile), you don't even need to specify it. It'll be picked up by default (if you have more than one of these standard names in your build directory, you better look up the make man page to see which takes precedence).

npm throws error without sudo

This looks like a permissions issue in your home directory. To reclaim ownership of the .npm directory execute:

sudo chown -R $(whoami) ~/.npm

How to automatically add user account AND password with a Bash script?

The solution that works on both Debian and Red Hat. Depends on perl, uses sha-512 hashes: 

cat userpassadd
    #!/usr/bin/env bash

    salt=$(cat /dev/urandom | tr -dc A-Za-z0-9/_- | head -c16)
    useradd -p $(perl -e "print crypt('$2', '\$6\$' . '$salt' . '\$')") $1

Usage:

userpassadd jim jimslongpassword

It can effectively be used as a one-liner, but you'll have to specify the password, salt and username at the right places yourself:

useradd -p $(perl -e "print crypt('pass', '\$6\$salt\$')") username

Is there any way to delete local commits in Mercurial?

You can get around this even more easily with the Rebase extension, just use hg pull --rebase and your commits are automatically re-comitted to the pulled revision, avoiding the branching issue.

What is the maximum length of a String in PHP?

PHP's string length is limited by the way strings are represented in PHP; memory does not have anything to do with it.

According to phpinternalsbook.com, strings are stored in struct { char *val; int len; } and since the maximum size of an int in C is 4 bytes, this effectively limits the maximum string size to 2GB.

How to set DialogFragment's width and height?

This will work perfectly.

@Override
public void onResume() {
    super.onResume();
    Window window = getDialog().getWindow();
    if(window == null) return;
    WindowManager.LayoutParams params = window.getAttributes();
    params.width = 400;
    params.height = 400;
    window.setAttributes(params);
}

A Simple AJAX with JSP example

I have used jQuery AJAX to make AJAX requests.

Check the following code:

<html>
<head>
    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js"></script>
    <script type="text/javascript">
        $(document).ready(function() {
            $('#call').click(function ()
            {
                $.ajax({
                    type: "post",
                    url: "testme", //this is my servlet
                    data: "input=" +$('#ip').val()+"&output="+$('#op').val(),
                    success: function(msg){      
                            $('#output').append(msg);
                    }
                });
            });

        });
    </script>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>JSP Page</title>
</head>
<body>
    input:<input id="ip" type="text" name="" value="" /><br></br>
    output:<input id="op" type="text" name="" value="" /><br></br>
    <input type="button" value="Call Servlet" name="Call Servlet" id="call"/>
    <div id="output"></div>
</body>

Java: How to insert CLOB into oracle database

You can very well do it with below code, i am giving you just the code to insert xml hope u are done with rest of other things..

import oracle.xdb.XMLType;

//now inside the class......
// this will be to convert xml into string

File file = new File(your file path);
FileReader fileR = new FileReader(file);
fileR.read(data);
String str = new String(data);

// now to enter it into db

conn = DriverManager.getConnection(serverName, userId, password);

XMLType objXml = XMLType.createXML(conn, str);

// inside the query statement put this code

objPreparedstatmnt.setObject(your value index, objXml);

I have done like this and it is working fine.

jQueryUI modal dialog does not show close button (x)

I had a similar issue. I was using jquery and jquery-ui. When I upgraded my versions, the close dialog image no longer appeared. My problem was that when I unzipped the js package that I downloaded, the directories did not have the execute permission.

So a quick chmod +x dir-name, and also for the sub-folders, did the trick. Without the execute permission on linux, apache cannot get into the folder.

How to set bootstrap navbar active class with Angular JS?

In conjunction with @Olivier's AngularStrap answer, I also implemented kevinknelson's answer from: https://github.com/twbs/bootstrap/issues/9013.

Natively, the Bootstrap3 navbar was not designed for a single-page (eg Angular) application and thus the menu when on a small screen was not collapsing upon click.

Java: Integer equals vs. ==

"==" always compare the memory location or object references of the values. equals method always compare the values. But equals also indirectly uses the "==" operator to compare the values.

Integer uses Integer cache to store the values from -128 to +127. If == operator is used to check for any values between -128 to 127 then it returns true. for other than these values it returns false .

Refer the link for some additional info

HTML Code for text checkbox '?'

Just make sure that your HTML file is encoded with UTF-8 and that your web server sends a HTTP header with that charset, then you just can write that character directly into your HTMl file.

http://www.w3.org/International/O-HTTP-charset

If you can't use UTF-8 for some reason, you can look up the codes in a unicode list such as http://en.wikipedia.org/wiki/List_of_Unicode_characters and use &#xABCD; where ABCD is the hexcode from that list (U+ABCD).

Cannot read property length of undefined

The id of the input seems is not WallSearch. Maybe you're confusing that name and id. They are two different properties. name is used to define the name by which the value is posted, while id is the unique identification of the element inside the DOM.

Other possibility is that you have two elements with the same id. The browser will pick any of these (probably the last, maybe the first) and return an element that doesn't support the value property.

Material Design not styling alert dialogs

Try this library:

https://github.com/avast/android-styled-dialogs

It's based on DialogFragments instead of AlertDialogs (like the one from @afollestad). The main advantage: Dialogs don't dismiss after rotation and callbacks still work.

'xmlParseEntityRef: no name' warnings while loading xml into a php file

This solve my problème:

$description = strip_tags($value['Description']);
$description=preg_replace('/&(?!#?[a-z0-9]+;)/', '&amp;', $description);
$description= preg_replace("/(^[\r\n]*|[\r\n]+)[\s\t]*[\r\n]+/", "\n", $description);
$description=str_replace(' & ', ' &amp; ', html_entity_decode((htmlspecialchars_decode($description))));

What is the best way to redirect a page using React Router?

Now with react-router v15.1 and onwards we can useHistory hook, This is super simple and clear way. Here is a simple example from the source blog. 

import { useHistory } from "react-router-dom";

function BackButton({ children }) {
  let history = useHistory()
  return (
    <button type="button" onClick={() => history.goBack()}>
      {children}
    </button>
  )
}

You can use this within any functional component and custom hooks. And yes this will not work with class components same as any other hook.

Learn more about this here https://reacttraining.com/blog/react-router-v5-1/#usehistory

Get current url in Angular

other.component.ts

So final correct solution is :

import { Component, OnInit } from '@angular/core';
import { Location } from '@angular/common';
import { Router } from '@angular/router'; 

/* 'router' it must be in small case */

    @Component({
      selector: 'app-other',
      templateUrl: './other.component.html',
      styleUrls: ['./other.component.css']
    })

    export class OtherComponent implements OnInit {

        public href: string = "";
        url: string = "asdf";

        constructor(private router : Router) {} // make variable private so that it would be accessible through out the component

        ngOnInit() {
            this.href = this.router.url;
            console.log(this.router.url);
        }
    }

How to link an image and target a new window

 
<a href="http://www.google.com" target="_blank">
  <img width="220" height="250" border="0" align="center"  src=""/>
</a>

How to provide shadow to Button

you can use this great library https://github.com/BluRe-CN/ComplexView and it is really easy to use

Can I remove the URL from my print css, so the web address doesn't print?

Sadly, no. The header and footer are generated by the browser. Only the end-user can change the footer - it might be an idea to give the user a step-by-step for each browser what to do. See for example here for a set of illustrated walk-throughs for windows based browsers.

The only alternative I know of is generating PDFs, with which you have full control over the printed output.

Spring cron expression for every after 30 minutes

According to the Quartz-Scheduler Tutorial It should be value="0 0/30 * * * ?"

The field order of the cronExpression is

1.Seconds

2.Minutes

3.Hours

4.Day-of-Month

5.Month

6.Day-of-Week

7.Year (optional field)

Ensure you have at least 6 parameters or you will get an error (year is optional)

React: Expected an assignment or function call and instead saw an expression

In my case the problem was the line with default instructions in switch block:

  handlePageChange = ({ btnType}) => {
    let { page } = this.state;
    switch (btnType) {
      case 'next':
        this.updatePage(page + 1);
        break;
      case 'prev':
        this.updatePage(page - 1);
        break;
      default: null;
    } 
  }

Instead of 

default: null;

The line

default: ;

worked for me.

iOS detect if user is on an iPad

You can also use this

#define IPAD UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad
...
if (IPAD) {
   // iPad
} else {
   // iPhone / iPod Touch
}

Python: Ignore 'Incorrect padding' error when base64 decoding

Incorrect padding error is caused because sometimes, metadata is also present in the encoded string If your string looks something like: 'data:image/png;base64,...base 64 stuff....' then you need to remove the first part before decoding it.

Say if you have image base64 encoded string, then try below snippet..

from PIL import Image
from io import BytesIO
from base64 import b64decode
imagestr = 'data:image/png;base64,...base 64 stuff....'
im = Image.open(BytesIO(b64decode(imagestr.split(',')[1])))
im.save("image.png")

click command in selenium webdriver does not work

This is a long standing issue with chromedriver(still present in 2020).

In Chrome I changed from a zoom of 90% to 100% and that solved the problem. ref

I find TheLifeOfSteve's answer more reliable.

Convert int to ASCII and back in Python

 
>>> ord("a")
97
>>> chr(97)
'a'

Jenkins - how to build a specific branch

I don't think you can both within the same jenkins job, what you need to do is to configure a new jenkins job which will have access to your github to retrieve branches and then you can choose which one to manually build.

Just mark it as a parameterized build, specify a name, and a parameter configured as git parameter

enter image description here

and now you can configure git options:

enter image description here

How to find server name of SQL Server Management Studio

Note: To connect to server on SQL Server Management Studio(SSMS), we must first install SQL Server.

So steps to proceed are as

Step 1 : Downloads and Install Microsoft SQL Server 2019

Step 2 : Downloads and Install SQL Server Management Studio

If still not able to see the Server name on SSMS, have a look at these three screen:

enter image description here enter image description here enter image description here

HTTP post XML data in C#

AlliterativeAlice's example helped me tremendously. In my case, though, the server I was talking to didn't like having single quotes around utf-8 in the content type. It failed with a generic "Server Error" and it took hours to figure out what it didn't like:

request.ContentType = "text/xml; encoding=utf-8";

What is unexpected T_VARIABLE in PHP?

There might be a semicolon or bracket missing a line before your pasted line.

It seems fine to me; every string is allowed as an array index.

How to get the list of files in a directory in a shell script?

 
for entry in "$search_dir"/*
do
  echo "$entry"
done

Ruby send JSON request

A simple json POST request example for those that need it even simpler than what Tom is linking to:

require 'net/http'

uri = URI.parse("http://www.example.com/search.json")
response = Net::HTTP.post_form(uri, {"search" => "Berlin"})

How to use conditional statement within child attribute of a Flutter Widget (Center Widget)

In my app I created a WidgetChooser widget so I can choose between widgets without conditional logic:

WidgetChooser(
      condition: true,
      trueChild: Text('This widget appears if the condition is true.'),
      falseChild: Text('This widget appears if the condition is false.'),
    );

This is the source for the WidgetChooser widget:

import 'package:flutter/widgets.dart';

class WidgetChooser extends StatelessWidget {
  final bool condition;
  final Widget trueChild;
  final Widget falseChild;

  WidgetChooser({@required this.condition, @required this.trueChild, @required this.falseChild});

  @override
  Widget build(BuildContext context) {
    if (condition) {
      return trueChild;
    } else {
      return falseChild;
    }
  }
}

How can I get the current page's full URL on a Windows/IIS server?

I use the following function to get the current, full URL. This should work on IIS and Apache.

function get_current_url() {

  $protocol = 'http';
  if ($_SERVER['SERVER_PORT'] == 443 || (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] == 'on')) {
    $protocol .= 's';
    $protocol_port = $_SERVER['SERVER_PORT'];
  } else {
    $protocol_port = 80;
  }

  $host = $_SERVER['HTTP_HOST'];
  $port = $_SERVER['SERVER_PORT'];
  $request = $_SERVER['PHP_SELF'];
  $query = isset($_SERVER['argv']) ? substr($_SERVER['argv'][0], strpos($_SERVER['argv'][0], ';') + 1) : '';

  $toret = $protocol . '://' . $host . ($port == $protocol_port ? '' : ':' . $port) . $request . (empty($query) ? '' : '?' . $query);

  return $toret;
}

Regex allow a string to only contain numbers 0 - 9 and limit length to 45

codaddict has provided the right answer. As for what you've tried, I'll explain why they don't make the cut:

  • [0-9]{1,45} is almost there, however it matches a 1-to-45-digit string even if it occurs within another longer string containing other characters. Hence you need ^ and $ to restrict it to an exact match.

  • ^[0-9]{45}*$ matches an exactly-45-digit string, repeated 0 or any number of times (*). That means the length of the string can only be 0 or a multiple of 45 (90, 135, 180...).

Are there benefits of passing by pointer over passing by reference in C++?

I like the reasoning by an article from "cplusplus.com:"

  1. Pass by value when the function does not want to modify the parameter and the value is easy to copy (ints, doubles, char, bool, etc... simple types. std::string, std::vector, and all other STL containers are NOT simple types.)

  2. Pass by const pointer when the value is expensive to copy AND the function does not want to modify the value pointed to AND NULL is a valid, expected value that the function handles.

  3. Pass by non-const pointer when the value is expensive to copy AND the function wants to modify the value pointed to AND NULL is a valid, expected value that the function handles.

  4. Pass by const reference when the value is expensive to copy AND the function does not want to modify the value referred to AND NULL would not be a valid value if a pointer was used instead.

  5. Pass by non-cont reference when the value is expensive to copy AND the function wants to modify the value referred to AND NULL would not be a valid value if a pointer was used instead.

  6. When writing template functions, there isn't a clear-cut answer because there are a few tradeoffs to consider that are beyond the scope of this discussion, but suffice it to say that most template functions take their parameters by value or (const) reference, however because iterator syntax is similar to that of pointers (asterisk to "dereference"), any template function that expects iterators as arguments will also by default accept pointers as well (and not check for NULL since the NULL iterator concept has a different syntax).

http://www.cplusplus.com/articles/z6vU7k9E/

What I take from this is that the major difference between choosing to use a pointer or reference parameter is if NULL is an acceptable value. That's it.

Whether the value is input, output, modifiable etc. should be in the documentation / comments about the function, after all.

How to change legend title in ggplot

Just to add to the list (the other options here didn't work for me), you can also use the function update_labels for ggplot:

p <- ggplot(df, aes(x=rating, fill=cond)) + 
           geom_density(alpha=.3) + 
           xlab("NEW RATING TITLE") + 
           ylab("NEW DENSITY TITLE")

update_labels(p, list(colour="MY NEW LEGEND TITLE")

This will also allow you to change x- and y-axis labels, with separate lines:

update_labels(p, list(x="NEW X LABEL",y="NEW Y LABEL")

How to monitor SQL Server table changes by using c#?

This isn't exactly a notification but in the title you say monitor and this can fit that scenario.

Using the SQL Server timestamp column can allow you to easily see any changes (that still persist) between queries.

The SQL Server timestamp column type is badly named in my opinion as it is not related to time at all, it's a database wide value that auto increments on any insert or update. You can select Max(timestamp) in a table you are after or return the timestamp from the row you just inserted then just select where timestamp > storedTimestamp, this will give you all the results that have been updated or inserted between those times.

As it's a database wide value too you can use your stored timestamp to check any table has had data written to it since you last checked/updated your stored timestamp.

Is CSS Turing complete?

As per this article, it's not. The article also argues that it's not a good idea to make it one.

To quote from one of the comments:

So, I do not believe that CSS is turing complete. There is no capability to define a function in CSS. In order for a system to be turing-complete it has to be possible to write an interpreter: a function that interprets expressions that denote programs to execute. CSS has no variables that are directly accessible to the user; so you cannot even model the structure that represents the program to be interpreted in CSS.

How can I convert String[] to ArrayList<String>

You can do the following:

String [] strings = new String [] {"1", "2" };
List<String> stringList = new ArrayList<String>(Arrays.asList(strings)); //new ArrayList is only needed if you absolutely need an ArrayList

Show spinner GIF during an $http request in AngularJS?

if you want to show loader for every http request call then you can use angular interceptor to manage http request calls ,

here is a sample code 

<body data-ng-app="myApp">
<div class="loader">
    <div id="loader"></div>
</div>

<script>
    var app = angular.module("myApp", []);

    app.factory('httpRequestInterceptor', ['$rootScope', '$location', function ($rootScope, $location) {
        return {
            request: function ($config) {
                $('.loader').show();
                return $config;
            },
            response: function ($config) {
                $('.loader').hide();
                return $config;
            },
            responseError: function (response) {
                return response;
            }
        };
    }]);

    app.config(['$stateProvider', '$urlRouterProvider', '$httpProvider',
        function ($stateProvider, $urlRouterProvider, $httpProvider) {
            $httpProvider.interceptors.push('httpRequestInterceptor');
        }]);

</script>
</body>

JavaScript: How to get parent element by selector?

 
var base_element = document.getElementById('__EXAMPLE_ELEMENT__');
for( var found_parent=base_element, i=100; found_parent.parentNode && !(found_parent=found_parent.parentNode).classList.contains('__CLASS_NAME__') && i>0; i-- );
console.log( found_parent );

Metadata file '.dll' could not be found

Visual Studio 2019 this worked for me:

  1. Close Visual Studio
  2. Delete the hidden .vs folder
  3. Reopen Visual Studio and rebuild the solution.

How to loop through all but the last item of a list?

If you want to get all the elements in the sequence pair wise, use this approach (the pairwise function is from the examples in the itertools module).

from itertools import tee, izip, chain

def pairwise(seq):
    a,b = tee(seq)
    b.next()
    return izip(a,b)

for current_item, next_item in pairwise(y):
    if compare(current_item, next_item):
        # do what you have to do

If you need to compare the last value to some special value, chain that value to the end

for current, next_item in pairwise(chain(y, [None])):

How to solve error: "Clock skew detected"?

One of the reason may be improper date/time of your PC.

In Ubuntu PC to check the date and time using:

date

Example, One of the ways to update date and time is:

date -s "23 MAR 2017 17:06:00"

how to know status of currently running jobs

 
EXECUTE master.dbo.xp_sqlagent_enum_jobs 1,''

Notice the column Running, obviously 1 means that it is currently running, and [Current Step]. This returns job_id to you, so you'll need to look these up, e.g.:

SELECT top 100 *
 FROM   msdb..sysjobs
 WHERE  job_id IN (0x9DAD1B38EB345D449EAFA5C5BFDC0E45, 0xC00A0A67D109B14897DD3DFD25A50B80, 0xC92C66C66E391345AE7E731BFA68C668)

How to return a specific status code and no contents from Controller?

This code might work for non-.NET Core MVC controllers:

this.HttpContext.Response.StatusCode = 418; // I'm a teapot
return Json(new { status = "mer" }, JsonRequestBehavior.AllowGet);

How do I refresh a DIV content?

You can use jQuery to achieve this using simple $.get method. .html work like innerHtml and replace the content of your div.

$.get("/YourUrl", {},
      function (returnedHtml) {
      $("#here").html(returnedHtml);
});

And call this using javascript setInterval method.

jquery, selector for class within id

Just use the plain ol' class selector.

$('#my_id .my_class')

It doesn't matter if the element also has other classes. It has the .my_class class, and it's somewhere inside #my_id, so it will match that selector.

Regarding performance

According to the jQuery selector performance documentation, it's faster to use the two selectors separately, like this:

$('#my_id').find('.my_class')

Here's the relevant part of the documentation:

ID-Based Selectors

// Fast:
$( "#container div.robotarm" );

// Super-fast:
$( "#container" ).find( "div.robotarm" );

The .find() approach is faster because the first selection is handled without going through the Sizzle selector engine – ID-only selections are handled using document.getElementById(), which is extremely fast because it is native to the browser.

Selecting by ID or by class alone (among other things) invokes browser-supplied functions like document.getElementById() which are quite rapid, whereas using a descendent selector invokes the Sizzle engine as mentioned which, although fast, is slower than the suggested alternative.

Removing black dots from li and ul

There you go, this is what I used to fix your problem:

CSS CODE

nav ul { list-style-type: none; }

HTML CODE

<nav>
<ul>
<li><a href="#">Milk</a>
   <ul>
   <li><a href="#">Goat</a></li>
   <li><a href="#">Cow</a></li>
   </ul>
</li>
<li><a href="#">Eggs</a>
   <ul>
   <li><a href="#">Free-range</a></li>
   <li><a href="#">Other</a></li>
   </ul>
</li>
<li><a href="#">Cheese</a>
   <ul>
   <li><a href="#">Smelly</a></li>
   <li><a href="#">Extra smelly</a></li>
   </ul>
</li>
</ul>
</nav>

How to make g++ search for header files in a specific directory?

 
gcc -I/path -L/path

  • -I /path path to include, gcc will find .h files in this path

  • -L /path contains library files, .a, .so

Display special characters when using print statement

Do you merely want to print the string that way, or do you want that to be the internal representation of the string? If the latter, create it as a raw string by prefixing it with r: r"Hello\tWorld\nHello World".

>>> a = r"Hello\tWorld\nHello World"
>>> a # in the interpreter, this calls repr()
'Hello\\tWorld\\nHello World'
>>> print a
Hello\tWorld\nHello World

Also, \s is not an escape character, except in regular expressions, and then it still has a much different meaning than what you're using it for.

Is it possible to capture the stdout from the sh DSL command in the pipeline

Note: The linked Jenkins issue has since been solved.

As mention in JENKINS-26133 it was not possible to get shell output as a variable. As a workaround suggested using of writ-read from temporary file. So, your example would have looked like:

sh "echo foo > result";
def output=readFile('result').trim()
echo "output=$output";

escaping question mark in regex javascript

You can delimit your regexp with slashes instead of quotes and then a single backslash to escape the question mark. Try this:

var gent = /I like your Apartment. Could we schedule a viewing\?/g;

PowerShell The term is not recognized as cmdlet function script file or operable program

You first have to 'dot' source the script, so for you :

. .\Get-NetworkStatistics.ps1

The first 'dot' asks PowerShell to load the script file into your PowerShell environment, not to start it. You should also use set-ExecutionPolicy Unrestricted or set-ExecutionPolicy AllSigned see(the Execution Policy instructions).

How do I set the default schema for a user in MySQL

There is no default database for user. There is default database for current session.

You can get it using DATABASE() function -

SELECT DATABASE();

And you can set it using USE statement -

USE database1;

You should set it manually - USE db_name, or in the connection string.

Intercept page exit event

Instead of an annoying confirmation popup, it would be nice to delay leaving just a bit (matter of milliseconds) to manage successfully posting the unsaved data to the server, which I managed for my site using writing dummy text to the console like this:

window.onbeforeunload=function(e){
  // only take action (iterate) if my SCHEDULED_REQUEST object contains data        
  for (var key in SCHEDULED_REQUEST){   
    postRequest(SCHEDULED_REQUEST); // post and empty SCHEDULED_REQUEST object
    for (var i=0;i<1000;i++){
      // do something unnoticable but time consuming like writing a lot to console
      console.log('buying some time to finish saving data'); 
    };
    break;
  };
}; // no return string --> user will leave as normal but data is send to server

Edit: See also Synchronous_AJAX and how to do that with jquery

How to get the selected item from ListView?

In touch mode, there is no focus and no selection. Your UI should use a different type of widget, such as radio buttons, for selection.

The documentation on ListView about this is terrible, just one obscure mention on setSelection.

How to set null to a GUID property

Choose your poison - if you can't change the type of the property to be nullable then you're going to have to use a "magic" value to represent NULL. Guid.Empty seems as good as any unless you have some specific reason for not wanting to use it. A second choice would be Guid.Parse("ffffffff-ffff-ffff-ffff-ffffffffffff") but that's a lot uglier IMHO.

How do I add my new User Control to the Toolbox or a new Winform?

One user control can't be applied to it ownself. So open another winform and the one will appear in the toolbox.

Difference between ref and out parameters in .NET

Ref parameters aren't required to be set in the function, whereas out parameters must be bound to a value before exiting the function. Variables passed as out may also be passed to a function without being initialized.

Assert that a method was called in a Python unit test

I use Mock (which is now unittest.mock on py3.3+) for this:

from mock import patch
from PyQt4 import Qt


@patch.object(Qt.QMessageBox, 'aboutQt')
def testShowAboutQt(self, mock):
    self.win.actionAboutQt.trigger()
    self.assertTrue(mock.called)

For your case, it could look like this:

import mock
from mock import patch


def testClearWasCalled(self):
   aw = aps.Request("nv1")
   with patch.object(aw, 'Clear') as mock:
       aw2 = aps.Request("nv2", aw)

   mock.assert_called_with(42) # or mock.assert_called_once_with(42)

Mock supports quite a few useful features, including ways to patch an object or module, as well as checking that the right thing was called, etc etc.

Caveat emptor! (Buyer beware!)

If you mistype assert_called_with (to assert_called_once or assert_called_wiht) your test may still run, as Mock will think this is a mocked function and happily go along, unless you use autospec=true. For more info read assert_called_once: Threat or Menace.

Get week day name from a given month, day and year individually in SQL Server

If you have SQL Server 2012:

If your date parts are integers then you can use DATEFROMPARTS function.

SELECT DATENAME( dw, DATEFROMPARTS( @Year, @Month, @Day ) )

If your date parts are strings, then you can use the CONCAT function.

SELECT DATENAME( dw, CONVERT( date, CONCAT( @Day, '/' , @Month, '/', @Year ), 103 ) )

Select first empty cell in column F starting from row 1. (without using offset )

I just wrote this one-liner to select the first empty cell found in a column based on a selected cell. Only works on first column of selected cells. Modify as necessary

Selection.End(xlDown).Range("A2").Select

phantomjs not waiting for "full" page load

This is an implementation of Supr's answer. Also it uses setTimeout instead of setInterval as Mateusz Charytoniuk suggested.

Phantomjs will exit in 1000ms when there isn't any request or response.

// load the module
var webpage = require('webpage');
// get timestamp
function getTimestamp(){
    // or use Date.now()
    return new Date().getTime();
}

var lastTimestamp = getTimestamp();

var page = webpage.create();
page.onResourceRequested = function(request) {
    // update the timestamp when there is a request
    lastTimestamp = getTimestamp();
};
page.onResourceReceived = function(response) {
    // update the timestamp when there is a response
    lastTimestamp = getTimestamp();
};

page.open(html, function(status) {
    if (status !== 'success') {
        // exit if it fails to load the page
        phantom.exit(1);
    }
    else{
        // do something here
    }
});

function checkReadyState() {
    setTimeout(function () {
        var curentTimestamp = getTimestamp();
        if(curentTimestamp-lastTimestamp>1000){
            // exit if there isn't request or response in 1000ms
            phantom.exit();
        }
        else{
            checkReadyState();
        }
    }, 100);
}

checkReadyState();

Convert int to char in java

My answer is similar to jh314's answer but I'll explain a little deeper.

What you should do in this case is:

int a = 1;
char b = (char)(a + '0');
System.out.println(b);

Here, we used '0' because chars are actually represented by ASCII values. '0' is a char and represented by the value of 48.

We typed (a + '0') and in order to add these up, Java converted '0' to its ASCII value which is 48 and a is 1 so the sum is 49. Then what we did is:

(char)(49)

We casted int to char. ASCII equivalent of 49 is '1'. You can convert any digit to char this way and is smarter and better way than using .toString() method and then subtracting the digit by .charAt() method.

How to load a resource from WEB-INF directory of a web archive

Use the getResourceAsStream() method on the ServletContext object, e.g.

servletContext.getResourceAsStream("/WEB-INF/myfile");

How you get a reference to the ServletContext depends on your application... do you want to do it from a Servlet or from a JSP?

EDITED: If you're inside a Servlet object, then call getServletContext(). If you're in JSP, use the predefined variable application.

MySQL, update multiple tables with one query

Let's say I have Table1 with primary key _id and a boolean column doc_availability; Table2 with foreign key _id and DateTime column last_update and I want to change the availability of a document with _id 14 in Table1 to 0 i.e unavailable and update Table2 with the timestamp when the document was last updated. The following query would do the task:

UPDATE Table1, Table2 
SET doc_availability = 0, last_update = NOW() 
WHERE Table1._id = Table2._id AND Table1._id = 14

How to create an Array with AngularJS's ng-model

It works fine for me: http://jsfiddle.net/qwertynl/htb9h/

My javascript:

var app = angular.module("myApp", [])
app.controller("MyCtrl", ['$scope', function($scope) {
    $scope.telephone = []; // << remember to set this
}]);

Very simple log4j2 XML configuration file using Console and File appender

log4j2 has a very flexible configuration system (which IMHO is more a distraction than a help), you can even use JSON. See https://logging.apache.org/log4j/2.x/manual/configuration.html for a reference.

Personally, I just recently started using log4j2, but I'm tending toward the "strict XML" configuration (that is, using attributes instead of element names), which can be schema-validated.

Here is my simple example using autoconfiguration and strict mode, using a "Property" for setting the filename:

<?xml version="1.0" encoding="UTF-8"?>
<Configuration monitorinterval="30" status="info" strict="true">
    <Properties>
        <Property name="filename">log/CelsiusConverter.log</Property>
    </Properties>
    <Appenders>
        <Appender type="Console" name="Console">
            <Layout type="PatternLayout" pattern="%d %p [%t] %m%n" />
        </Appender>
        <Appender type="Console" name="FLOW">
            <Layout type="PatternLayout" pattern="%C{1}.%M %m %ex%n" />
        </Appender>
        <Appender type="File" name="File" fileName="${filename}">
            <Layout type="PatternLayout" pattern="%d %p %C{1.} [%t] %m%n" />
        </Appender>
    </Appenders>
    <Loggers>
        <Root level="debug">
            <AppenderRef ref="File" />
            <AppenderRef ref="Console" />
            <!-- Use FLOW to trace down exact method sending the msg -->
            <!-- <AppenderRef ref="FLOW" /> -->
        </Root>
    </Loggers>
</Configuration>

How can I create a self-signed cert for localhost?

I would recomment Pluralsight's tool for creating self-signed-certs: http://blog.pluralsight.com/selfcert-create-a-self-signed-certificate-interactively-gui-or-programmatically-in-net

Make your cert as a .pfx and import it into IIS. And add it as a trusted root cert authority.

Fix height of a table row in HTML Table

This works, as long as you remove the height attribute from the table.

<table id="content" border="0px" cellspacing="0px" cellpadding="0px">
  <tr><td height='9px' bgcolor="#990000">Upper</td></tr>
  <tr><td height='100px' bgcolor="#990099">Lower</td></tr>
</table>

Android Error - Open Failed ENOENT

Put the text file in the assets directory. If there isnt an assets dir create one in the root of the project. Then you can use Context.getAssets().open("BlockForTest.txt"); to open a stream to this file.

php multidimensional array get values

This is the way to iterate on this array:

foreach($hotels as $row) {
       foreach($row['rooms'] as $k) {
             echo $k['boards']['board_id'];
             echo $k['boards']['price'];
       }
}

You want to iterate on the hotels and the rooms (the ones with numeric indexes), because those seem to be the "collections" in this case. The other arrays only hold and group properties.

Firefox 'Cross-Origin Request Blocked' despite headers

If the aforementioned answers don't help then check whether the backend server is up and running or not as in my case the server crashed and this error turns out to be totally misleading.

Typing the Enter/Return key using Python and Selenium

When you don't want to search any locator, you can use the Robot class. For example,

Robot robot = new Robot();
robot.keyPress(KeyEvent.VK_ENTER);
robot.keyRelease(KeyEvent.VK_ENTER);

In git how is fetch different than pull and how is merge different than rebase?

pull vs fetch:

The way I understand this, is that git pull is simply a git fetch followed by git merge. I.e. you fetch the changes from a remote branch and then merge it into the current branch.

merge vs rebase:

A merge will do as the command says; merge the differences between current branch and the specified branch (into the current branch). I.e. the command git merge another_branch will the merge another_branch into the current branch.

A rebase works a bit differently and is kind of cool. Let's say you perform the command git rebase another_branch. Git will first find the latest common version between the current branch and another_branch. I.e. the point before the branches diverged. Then git will move this divergent point to the head of the another_branch. Finally, all the commits in the current branch since the original divergent point are replayed from the new divergent point. This creates a very clean history, with fewer branches and merges.

However, it is not without pitfalls! Since the version history is "rewritten", you should only do this if the commits only exists in your local git repo. That is: Never do this if you have pushed the commits to a remote repo.

The explanation on rebasing given in this online book is quite good, with easy-to-understand illustrations.

pull with rebasing instead of merge

I'm actually using rebase quite a lot, but usually it is in combination with pull:

git pull --rebase

will fetch remote changes and then rebase instead of merge. I.e. it will replay all your local commits from the last time you performed a pull. I find this much cleaner than doing a normal pull with merging, which will create an extra commit with the merges.

Can a foreign key be NULL and/or duplicate?

Here's an example using Oracle syntax:
First let's create a table COUNTRY

CREATE TABLE TBL_COUNTRY ( COUNTRY_ID VARCHAR2 (50) NOT NULL ) ;
ALTER TABLE TBL_COUNTRY ADD CONSTRAINT COUNTRY_PK PRIMARY KEY ( COUNTRY_ID ) ;

Create the table PROVINCE

CREATE TABLE TBL_PROVINCE(
PROVINCE_ID VARCHAR2 (50) NOT NULL ,
COUNTRY_ID  VARCHAR2 (50)
);
ALTER TABLE TBL_PROVINCE ADD CONSTRAINT PROVINCE_PK PRIMARY KEY ( PROVINCE_ID ) ;
ALTER TABLE TBL_PROVINCE ADD CONSTRAINT PROVINCE_COUNTRY_FK FOREIGN KEY ( COUNTRY_ID ) REFERENCES TBL_COUNTRY ( COUNTRY_ID ) ;

This runs perfectly fine in Oracle. Notice the COUNTRY_ID foreign key in the second table doesn't have "NOT NULL".

Now to insert a row into the PROVINCE table, it's sufficient to only specify the PROVINCE_ID. However, if you chose to specify a COUNTRY_ID as well, it must exist already in the COUNTRY table.

How do I redirect in expressjs while passing some context?

use app.set & app.get

Setting data

router.get(
  "/facebook/callback",
  passport.authenticate("facebook"),
  (req, res) => {
    req.app.set('user', res.req.user)
    return res.redirect("/sign");
  }
);

Getting data

router.get("/sign", (req, res) => {
  console.log('sign', req.app.get('user'))
});

How do I format date value as yyyy-mm-dd using SSIS expression builder?

Correct expression is

"source " + (DT_STR,4,1252)DATEPART( "yyyy" , getdate() ) + "-" +
RIGHT("0" + (DT_STR,4,1252)DATEPART( "mm" , getdate() ), 2) + "-" +
RIGHT("0" + (DT_STR,4,1252)DATEPART( "dd" , getdate() ), 2) +".CSV"

Type List vs type ArrayList in Java

The only case that I am aware of where (2) can be better is when using GWT, because it reduces application footprint (not my idea, but the google web toolkit team says so). But for regular java running inside the JVM (1) is probably always better.

What is the difference between attribute and property?

Delphi used properties and they have found their way into .NET (because it has the same architect).

In Delphi they are often used in combination with runtime type information such that the integrated property editor can be used to set the property in designtime.

Properties are not always related to fields. They can be functions that possible have side effects (but of course that is very bad design).

golang why don't we have a set datastructure

Partly, because Go doesn't have generics (so you would need one set-type for every type, or fall back on reflection, which is rather inefficient).

Partly, because if all you need is "add/remove individual elements to a set" and "relatively space-efficient", you can get a fair bit of that simply by using a map[yourtype]bool (and set the value to true for any element in the set) or, for more space efficiency, you can use an empty struct as the value and use _, present = the_setoid[key] to check for presence.

How can I make a program wait for a variable change in javascript?

What worked for me (I looked all over the place and ended up using someone's jsfiddler / very slightly modifying it - worked nicely) was to set that variable to an object with a getter and setter, and the setter triggers the function that is waiting for variable change.

var myVariableImWaitingOn = function (methodNameToTriggerWhenChanged){
    triggerVar = this;
    triggerVar.val = '';
    triggerVar.onChange = methodNameToTriggerWhenChanged;
    this.SetValue(value){
        if (value != 'undefined' && value != ''){
            triggerVar.val = value; //modify this according to what you're passing in -
            //like a loop if an array that's only available for a short time, etc
            triggerVar.onChange(); //could also pass the val to the waiting function here
            //or the waiting function can just call myVariableImWaitingOn.GetValue()
        }
    };
    this.GetValue(){
        return triggerVar.val();
    };
 };

Saving a high resolution image in R

A simpler way is

ggplot(data=df, aes(x=xvar, y=yvar)) + 
geom_point()

ggsave(path = path, width = width, height = height, device='tiff', dpi=700)

Html.fromHtml deprecated in Android N

update: as @Andy mentioned below Google has created HtmlCompat which can be used instead of the method below. Add this dependency implementation 'androidx.core:core:1.0.1 to the build.gradle file of your app. Make sure you use the latest version of androidx.core:core.

This allows you to use: 

HtmlCompat.fromHtml(html, HtmlCompat.FROM_HTML_MODE_LEGACY);

You can read more about the different flags on the HtmlCompat-documentation

original answer: In Android N they introduced a new Html.fromHtml method. Html.fromHtml now requires an additional parameter, named flags. This flag gives you more control about how your HTML gets displayed.

On Android N and above you should use this new method. The older method is deprecated and may be removed in the future Android versions.

You can create your own Util-method which will use the old method on older versions and the newer method on Android N and above. If you don't add a version check your app will break on lower Android versions. You can use this method in your Util class. 

@SuppressWarnings("deprecation")
public static Spanned fromHtml(String html){
    if(html == null){
        // return an empty spannable if the html is null
        return new SpannableString("");
    }else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
        // FROM_HTML_MODE_LEGACY is the behaviour that was used for versions below android N
        // we are using this flag to give a consistent behaviour
        return Html.fromHtml(html, Html.FROM_HTML_MODE_LEGACY);
    } else {
        return Html.fromHtml(html);
    }
}

You can convert the HTML.FROM_HTML_MODE_LEGACY into an additional parameter if you want. This gives you more control about it which flag to use.

You can read more about the different flags on the Html class documentation

Query to check index on a table

If you're using MySQL you can run SHOW KEYS FROM table or SHOW INDEXES FROM table

What is the difference between Python's list methods append and extend?

The following two snippets are semantically equivalent:

for item in iterator:
    a_list.append(item)

and

a_list.extend(iterator)

The latter may be faster as the loop is implemented in C.

jQuery keypress() event not firing?

With jQuery, I've done it this way:

function checkKey(e){
     switch (e.keyCode) {
        case 40:
            alert('down');
            break;
        case 38:
            alert('up');
            break;
        case 37:
            alert('left');
            break;
        case 39:
            alert('right');
            break;
        default:
            alert('???');  
            }      
}

if ($.browser.mozilla) {
    $(document).keypress (checkKey);
} else {
    $(document).keydown (checkKey);
}

Also, try these plugins, which looks like they do all that work for you:

http://www.openjs.com/scripts/events/keyboard_shortcuts

http://www.webappers.com/2008/07/31/bind-a-hot-key-combination-with-jquery-hotkeys/

What does this mean? "Parse error: syntax error, unexpected T_PAAMAYIM_NEKUDOTAYIM"

The error is down to an "inappropriate use" of the double colon operator:

return $cnf::getConfig($key);

as by using the :: you're attempting to call a static method of the class itself. In your example you want to call a non-static method on an instantiated object.

I think what you want is:

return $cnf->getConfig($key);

VirtualBox: mount.vboxsf: mounting failed with the error: No such device

Shared folder was earlier working for me but all f sudden it stopped working (Virualbox - host was Windows 7, Guest was OpenSuSe)

modprobe -a vboxguest vboxsf vboxvideo

then mount -t vboxsf testsf /opt/tsf (testsf was the folder in Windows C drive which was added in Virtualbox shared folder --- and /opt/tsf is the folder in OpenSuse

Changing variable names with Python for loops

You could access your class's __dict__ attribute:

for i in range(3)
     self.__dict__['group%d' % i]=self.getGroup(selected, header+i)

But why can't you just use an array named group?

go get results in 'terminal prompts disabled' error for github private repo

If you just want go get to work real fast, and move along with your work...

Just export GIT_TERMINAL_PROMPT=1

$ export GIT_TERMINAL_PROMPT=1
$ go get [whatever]

It will now prompt you for a user/pass for the rest of your shell session. Put this in your .profile or setup git as above for a more permanent solution.

How to use glOrtho() in OpenGL?

Have a look at this picture: Graphical Projections enter image description here

The glOrtho command produces an "Oblique" projection that you see in the bottom row. No matter how far away vertexes are in the z direction, they will not recede into the distance.

I use glOrtho every time I need to do 2D graphics in OpenGL (such as health bars, menus etc) using the following code every time the window is resized:

glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(0.0f, windowWidth, windowHeight, 0.0f, 0.0f, 1.0f);

This will remap the OpenGL coordinates into the equivalent pixel values (X going from 0 to windowWidth and Y going from 0 to windowHeight). Note that I've flipped the Y values because OpenGL coordinates start from the bottom left corner of the window. So by flipping, I get a more conventional (0,0) starting at the top left corner of the window rather.

Note that the Z values are clipped from 0 to 1. So be careful when you specify a Z value for your vertex's position, it will be clipped if it falls outside that range. Otherwise if it's inside that range, it will appear to have no effect on the position except for Z tests.

Sql Server 'Saving changes is not permitted' error ? Prevent saving changes that require table re-creation

Copied from this link " ... Important We strongly recommend that you do not work around this problem by turning off the Prevent saving changes that require table re-creation option. For more information about the risks of turning off this option, see the "More information" section. ''

" ...To work around this problem, use Transact-SQL statements to make the changes to the metadata structure of a table. For additional information refer to the following topic in SQL Server Books Online

For example, to change MyDate column of type datetime in at table called MyTable to accept NULL values you can use:

alter table MyTable alter column MyDate7 datetime NULL "

package javax.servlet.http does not exist

If you are using Ant and trying to build then you need to :

  1. Specify tomcat location by <property name="tomcat-home" value="C:\xampp\tomcat" />

  2. Add tomcat libs to your already defined path for jars by

    <path id="libs"> <fileset includes="*.jar" dir="${WEB-INF}/lib" /> <fileset includes="*.jar" dir="${tomcat-home}/bin" /> <fileset includes="*.jar" dir="${tomcat-home}/lib" /> </path>

Styling Form with Label above Inputs

There is no need to add any extra div wrapper as others suggest.

The simplest way is to wrap your input element inside a related label tag and set input style to display:block.

Bonus point earned: now you don't need to set the labels for attribute. Because every label target the nested input.

<form name="message" method="post">
    <section>
        <label class="left">
            Name
            <input id="name" type="text" name="name">
        </label>
        <label class="right">
            Email
            <input id="email" type="text" name="email">
        </label>
    </section>
</form>

https://jsfiddle.net/Tomanek1/sguh5k17/15/

How to get current PHP page name

In your case you can use __FILE__ variable !
It should help.
It is one of predefined.
Read more about predefined constants in PHP http://php.net/manual/en/language.constants.predefined.php

Count Rows in Doctrine QueryBuilder

For people who are using only Doctrine DBAL and not the Doctrine ORM, they will not be able to access the getQuery() method because it doesn't exists. They need to do something like the following.

$qb = new QueryBuilder($conn);
$count = $qb->select("count(id)")->from($tableName)->execute()->fetchColumn(0);

htaccess - How to force the client's browser to clear the cache?

Adding 'random' numbers to URLs seems inelegant and expensive to me. It also spoils the URL of the pages, which can look like index.html?t=1614333283241 and btw users will have dozens of URLs cached for only one use.
I think this kind of things is what .htaccess files are meant to solve at the server side, between your functional code an the users.

I copy/paste this code from here that allows filtering by file extension to force the browser not to cache them. If you want to return to normal behavior, just delete or comment it.

Create or edit an .htaccess file on every folder you want to prevent caching, then paste this code changing file extensions to your needs, or even to match one individual file.
If the file already exists on your host be cautious modifying what's in it.
(kudos to the link)

# DISABLE CACHING
<IfModule mod_headers.c>
    Header set Cache-Control "no-cache, no-store, must-revalidate"
    Header set Pragma "no-cache"
    Header set Expires 0
</IfModule>

<FilesMatch "\.(css|flv|gif|htm|html|ico|jpe|jpeg|jpg|js|mp3|mp4|png|pdf|swf|txt)$">
    <IfModule mod_expires.c>
        ExpiresActive Off
    </IfModule>
    <IfModule mod_headers.c>
        FileETag None
        Header unset ETag
        Header unset Pragma
        Header unset Cache-Control
        Header unset Last-Modified
        Header set Pragma "no-cache"
        Header set Cache-Control "max-age=0, no-cache, no-store, must-revalidate"
        Header set Expires "jue, 1 Jan 1970 00:00:00 GMT"
    </IfModule>
</FilesMatch>

Receiving "Attempted import error:" in react app

This is another option:

export default function Counter() {

}

Getting GET "?" variable in laravel

Query params are used like this:

use Illuminate\Http\Request;

class MyController extends BaseController{

    public function index(Request $request){
         $param = $request->query('param');
    }

How should I resolve java.lang.IllegalArgumentException: protocol = https host = null Exception?

Might help some else - I came here because I missed putting two // after http:. This is what I had:

http:/abc.my.domain.com:55555/update

SyntaxError: Unexpected Identifier in Chrome's Javascript console

I got this error Unexpected identifier because of a missing semi-colon ; at the end of a line. Anyone wandering here for other than above-mentioned solutions, This might also be the cause of this error.

How to use global variables in React Native?

If you just want to pass some data from one screen to the next, you can pass them with the navigation.navigate method like this:

<Button onPress={()=> {this.props.navigation.navigate('NextScreen',{foo:bar)} />

and in 'NextScreen' you can access them with the navigation.getParam() method:

let foo=this.props.navigation.getParam(foo);

But it can get really "messy" if you have more than a couple of variables to pass..

receiver type *** for instance message is a forward declaration

FWIW, I got this error when I was implementing core data in to an existing project. It turned out I forgot to link CoreData.h to my project. I had already added the CoreData framework to my project but solved the issue by linking to the framework in my pre-compiled header just like Apple's templates do:

#import <Availability.h>

#ifndef __IPHONE_5_0
#warning "This project uses features only available in iOS SDK 5.0 and later."
#endif

#ifdef __OBJC__
    #import <UIKit/UIKit.h>
    #import <Foundation/Foundation.h>
    #import <CoreData/CoreData.h>
#endif

SQL Server query to find all current database names

You can also use these ways:

EXEC sp_helpdb

and:

SELECT name FROM sys.sysdatabases

Recommended Read:

Don't forget to have a look at sysdatabases VS sys.sysdatabases

A similar thread.

How do you 'redo' changes after 'undo' with Emacs?

If you want to redo the last operation, do the following.

  1. ESC
  2. Do another undo (C + /)

What is the maximum length of a table name in Oracle?

I'm working on Oracle 12c 12.1. However, doesn't seem like it allows more than 30 characters for column/table names.

Read through an oracle page which mentions 30 bytes. https://docs.oracle.com/database/121/SQLRF/sql_elements008.htm#SQLRF00223

In 12c although the all_tab_columns do say VARCHAR2(128) for Table_Name, it does not allow more than 30 bytes name.

Found another article about 12c R2, which seems to be allowing this up to 128 characters. https://community.oracle.com/ideas/3338

How to compile a 64-bit application using Visual C++ 2010 Express?

As what Jakob said: windows sdk 7.1 cannot be installed if MS VC++ x64 and x86 runtimes and redisrtibutables of version 10.0.40219 are present. after removing them win sdk install is okay, VS C++ SP1 can be installed fine again.

Kind regards

How can I override Bootstrap CSS styles?

Using !important is not a good option, as you will most likely want to override your own styles in the future. That leaves us with CSS priorities.

Basically, every selector has its own numerical 'weight':

  • 100 points for IDs
  • 10 points for classes and pseudo-classes
  • 1 point for tag selectors and pseudo-elements
  • Note: If the element has inline styling that automatically wins (1000 points)

Among two selector styles browser will always choose the one with more weight. Order of your stylesheets only matters when priorities are even - that's why it is not easy to override Bootstrap.

Your option is to inspect Bootstrap sources, find out how exactly some specific style is defined, and copy that selector so your element has equal priority. But we kinda loose all Bootstrap sweetness in the process.

The easiest way to overcome this is to assign additional arbitrary ID to one of the root elements on your page, like this: <body id="bootstrap-overrides">

This way, you can just prefix any CSS selector with your ID, instantly adding 100 points of weight to the element, and overriding Bootstrap definitions:

/* Example selector defined in Bootstrap */
.jumbotron h1 { /* 10+1=11 priority scores */
  line-height: 1;
  color: inherit;
}

/* Your initial take at styling */
h1 { /* 1 priority score, not enough to override Bootstrap jumbotron definition */
  line-height: 1;
  color: inherit;
}

/* New way of prioritization */
#bootstrap-overrides h1 { /* 100+1=101 priority score, yay! */
  line-height: 1;
  color: inherit;
}

How do Common Names (CN) and Subject Alternative Names (SAN) work together?

CABForum Baseline Requirements

I see no one has mentioned the section in the Baseline Requirements yet. I feel they are important.

Q: SSL - How do Common Names (CN) and Subject Alternative Names (SAN) work together?
A: Not at all. If there are SANs, then CN can be ignored. -- At least if the software that does the checking adheres very strictly to the CABForum's Baseline Requirements.

(So this means I can't answer the "Edit" to your question. Only the original question.)

CABForum Baseline Requirements, v. 1.2.5 (as of 2 April 2015), page 9-10:

9.2.2 Subject Distinguished Name Fields
a. Subject Common Name Field
Certificate Field: subject:commonName (OID 2.5.4.3)
Required/Optional: Deprecated (Discouraged, but not prohibited)
Contents: If present, this field MUST contain a single IP address or Fully-Qualified Domain Name that is one of the values contained in the Certificate’s subjectAltName extension (see Section 9.2.1).

EDIT: Links from @Bruno's comment

RFC 2818: HTTP Over TLS, 2000, Section 3.1: Server Identity:

If a subjectAltName extension of type dNSName is present, that MUST be used as the identity. Otherwise, the (most specific) Common Name field in the Subject field of the certificate MUST be used. Although the use of the Common Name is existing practice, it is deprecated and Certification Authorities are encouraged to use the dNSName instead.

RFC 6125: Representation and Verification of Domain-Based Application Service Identity within Internet Public Key Infrastructure Using X.509 (PKIX) Certificates in the Context of Transport Layer Security (TLS), 2011, Section 6.4.4: Checking of Common Names:

[...] if and only if the presented identifiers do not include a DNS-ID, SRV-ID, URI-ID, or any application-specific identifier types supported by the client, then the client MAY as a last resort check for a string whose form matches that of a fully qualified DNS domain name in a Common Name field of the subject field (i.e., a CN-ID).

Should image size be defined in the img tag height/width attributes or in CSS?

Definitely not both. Other than that I'd have to say it's a personal preference. I'd use css if I had many images the same size to reduce code.

.my_images img {width: 20px; height:20px}

In the long term CSS may win out due to HTML attribute deprecation and more likely due to the growth of vector image formats like SVG where it can actually make sense to scale images using non-pixel based units like % or em.