Programs & Examples On #Achartengine

A charting software library for Android applications by Dan Dromereschi.

add maven repository to build.gradle

Android Studio Users:

If you want to use grade, go to and search for your maven repo. Then, click on the "latest version" and in the details page on the bottom left you will see "Gradle" where you can then copy/paste that link into your app's build.gradle.

enter image description here

Android charting libraries

  • Achartengine: I have used this. Although for real time graph this might not give good performance if you do not tweak properly.

How to set a default value with Html.TextBoxFor?

It turns out that if you don't specify the Model to the View method within your controller, it doesn't create a object for you with the default values.

public ViewResult Create()
  // Loads default values
  Instructor i = new Instructor();
  return View("Create", i);

public ViewResult Create()
  // Does not load default values from instructor
  return View("Create");

React Native fixed footer

Suggestion 1

=> Body with fixed footer

<View style={{ flex: 1, backgroundColor: 'gray' }}>

        <View style={{ flex: 9, backgroundColor: 'gray',alignItems: 'center', justifyContent: 'center',  }}>
          <Text style={{color:'white'}}>...Header or Body</Text>

        <View style={{ flex: 1, backgroundColor: 'yellow', alignItems: 'center', justifyContent: 'center', }}>


Demo Image

Edit 2

=> Body & Fixed footer with tabs

<View style={{ flex: 1, backgroundColor: 'gray' }}>

        <View style={{ flex: 9, backgroundColor: 'gray', alignItems: 'center', justifyContent: 'center', }}>
          <Text style={{ color: 'white' }}>...Header or Body</Text>

        <View style={{ flex: 1, backgroundColor: 'yellow', alignItems: 'center', justifyContent: 'center', }}>
          <View style={{ flex: 1, flexDirection: 'row' }}>
            <TouchableOpacity style={{ flex: 1, alignItems: 'center', justifyContent: 'center', backgroundColor: 'white' }}>
            <TouchableOpacity style={{ flex: 1, alignItems: 'center', justifyContent: 'center', backgroundColor: 'white' }}>

enter image description here


import {TouchableOpacity} from 'react-native'


We can use this simple footer without react bottom navigation

How to verify a Text present in the loaded page through WebDriver

Below code is most suitable way to verify a text on page. You can use any one out of 8 locators as per your convenience.

String Verifytext= driver.findElement(By.tagName("body")).getText().trim(); Assert.assertEquals(Verifytext, "Paste the text here which needs to be verified");

How to use jquery or ajax to update razor partial view in c#/ for a MVC project

The main concept of partial view is returning the HTML code rather than going to the partial view it self.

public ActionResult Calendar(int year)
    var dates = new List<DateTime>() { /* values based on year */ };
    HolidayViewModel model = new HolidayViewModel {
        Dates = dates
    return PartialView("HolidayPartialView", model);

this action return the HTML code of the partial view ("HolidayPartialView").

To refresh partial view replace the existing item with the new filtered item using the jQuery below.

                url: "/Holiday/Calendar",
                type: "GET",
                data: { year: ((val * 1) + 1) }
            .done(function(partialViewResult) {

How to set my default shell on Mac?

You can use chsh to change a user's shell.

Run the following code, for instance, to change your shell to Zsh

chsh -s /bin/zsh

As described in the manpage, and by Lorin, if the shell is not known by the OS, you have to add it to its known list: /etc/shells.

React Checkbox not sending onChange

In the scenario you would NOT like to use the onChange handler on the input DOM, you can use the onClick property as an alternative. The defaultChecked, the condition may leave a fixed state for v16 IINM.

 class CrossOutCheckbox extends Component {
          this.handleChange = this.handleChange.bind(this);
          if (target.checked){
    = "";
          } else {
             target.setAttribute('checked', true);
    = "line-through";
         return (
              <label style={{textDecoration: this.props.complete?"line-through":""}}>
                 <input type="checkbox"

I hope this helps someone in the future.

Why can't I reference my class library?

Unfortunately the only thing that worked for me was completely deleting and recreating the class library project, after having temporarily copied the class files in it elsewhere. Only then would the ASP.Net web project recognise the using statements that referred to the class library project. This was with Visual Studio 2010, not using ReSharper.

Call web service in excel

For an updated answer see this SO question:

calling web service using VBA code in excel 2010

Both threads should be merged though.

Can an Android Toast be longer than Toast.LENGTH_LONG?

If you need a long Toast, there's a practical alternative, but it requires your user to click on an OK button to make it go away. You can use an AlertDialog like this:

String message = "This is your message";
new AlertDialog.Builder(YourActivityName.this)
    .setTitle("Optional Title (you can omit this)")
    .setPositiveButton("ok", null)

If you have a long message, chances are, you don't know how long it will take for your user to read the message, so sometimes it is a good idea to require your user to click on an OK button to continue. In my case, I use this technique when a user clicks on a help icon.

What are the basic rules and idioms for operator overloading?

Overloading new and delete

Note: This only deals with the syntax of overloading new and delete, not with the implementation of such overloaded operators. I think that the semantics of overloading new and delete deserve their own FAQ, within the topic of operator overloading I can never do it justice.


In C++, when you write a new expression like new T(arg) two things happen when this expression is evaluated: First operator new is invoked to obtain raw memory, and then the appropriate constructor of T is invoked to turn this raw memory into a valid object. Likewise, when you delete an object, first its destructor is called, and then the memory is returned to operator delete.
C++ allows you to tune both of these operations: memory management and the construction/destruction of the object at the allocated memory. The latter is done by writing constructors and destructors for a class. Fine-tuning memory management is done by writing your own operator new and operator delete.

The first of the basic rules of operator overloading – don’t do it – applies especially to overloading new and delete. Almost the only reasons to overload these operators are performance problems and memory constraints, and in many cases, other actions, like changes to the algorithms used, will provide a much higher cost/gain ratio than attempting to tweak memory management.

The C++ standard library comes with a set of predefined new and delete operators. The most important ones are these:

void* operator new(std::size_t) throw(std::bad_alloc); 
void  operator delete(void*) throw(); 
void* operator new[](std::size_t) throw(std::bad_alloc); 
void  operator delete[](void*) throw(); 

The first two allocate/deallocate memory for an object, the latter two for an array of objects. If you provide your own versions of these, they will not overload, but replace the ones from the standard library.
If you overload operator new, you should always also overload the matching operator delete, even if you never intend to call it. The reason is that, if a constructor throws during the evaluation of a new expression, the run-time system will return the memory to the operator delete matching the operator new that was called to allocate the memory to create the object in. If you do not provide a matching operator delete, the default one is called, which is almost always wrong.
If you overload new and delete, you should consider overloading the array variants, too.

Placement new

C++ allows new and delete operators to take additional arguments.
So-called placement new allows you to create an object at a certain address which is passed to:

class X { /* ... */ };
char buffer[ sizeof(X) ];
void f()
  X* p = new(buffer) X(/*...*/);
  // ... 
  p->~X(); // call destructor 

The standard library comes with the appropriate overloads of the new and delete operators for this:

void* operator new(std::size_t,void* p) throw(std::bad_alloc); 
void  operator delete(void* p,void*) throw(); 
void* operator new[](std::size_t,void* p) throw(std::bad_alloc); 
void  operator delete[](void* p,void*) throw(); 

Note that, in the example code for placement new given above, operator delete is never called, unless the constructor of X throws an exception.

You can also overload new and delete with other arguments. As with the additional argument for placement new, these arguments are also listed within parentheses after the keyword new. Merely for historical reasons, such variants are often also called placement new, even if their arguments are not for placing an object at a specific address.

Class-specific new and delete

Most commonly you will want to fine-tune memory management because measurement has shown that instances of a specific class, or of a group of related classes, are created and destroyed often and that the default memory management of the run-time system, tuned for general performance, deals inefficiently in this specific case. To improve this, you can overload new and delete for a specific class:

class my_class { 
    // ... 
    void* operator new();
    void  operator delete(void*,std::size_t);
    void* operator new[](size_t);
    void  operator delete[](void*,std::size_t);
    // ... 

Overloaded thus, new and delete behave like static member functions. For objects of my_class, the std::size_t argument will always be sizeof(my_class). However, these operators are also called for dynamically allocated objects of derived classes, in which case it might be greater than that.

Global new and delete

To overload the global new and delete, simply replace the pre-defined operators of the standard library with our own. However, this rarely ever needs to be done.

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

I'd advise to go for Gordon's solution as it is more performant than substr():


$string = 'abcdef';
$repetitions = 10000000;

echo "\n\n";
echo "----------------------------------\n";
echo $repetitions . " repetitions...\n";
echo "----------------------------------\n";
echo "\n\n";

$start = microtime(true);
for($i=0; $i<$repetitions; $i++)
    $x = substr($string, -1);

echo "substr() took " . (microtime(true) - $start) . "seconds\n";

$start = microtime(true);
for($i=0; $i<$repetitions; $i++)
    $x = $string[strlen($string)-1];

echo "array access took " . (microtime(true) - $start) . "seconds\n";


outputs something like

 10000000 repetitions...

 substr() took 2.0285921096802seconds 
 array access took 1.7474739551544seconds

Set Locale programmatically

public static void forceLocale(Context context, String localeCode) {
    String localeCodeLowerCase = localeCode.toLowerCase();

    Resources resources = context.getApplicationContext().getResources();
    Configuration overrideConfiguration = resources.getConfiguration();
    Locale overrideLocale = new Locale(localeCodeLowerCase);

    } else {
        overrideConfiguration.locale = overrideLocale;

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
    } else {
        resources.updateConfiguration(overrideConfiguration, null);

Just use this helper method to force specific locale.

UDPATE 22 AUG 2017. Better use this approach.

Android: Scale a Drawable or background image?

you'll have to pre-scale that drawable before you use it as a background

How do you pass a function as a parameter in C?

It's not really a function, but it is an localised piece of code. Of course it doesn't pass the code just the result. It won't work if passed to an event dispatcher to be run at a later time (as the result is calculated now and not when the event occurs). But it does localise your code into one place if that is all you are trying to do.

#include <stdio.h>

int IncMultInt(int a, int b)
    return a * b;

int main(int argc, char *argv[])

    int a = 5;
    int b = 7;

    printf("%d * %d = %d\n", a, b, IncMultInt(a, b));

    b = 9;

    // Create some local code with it's own local variable
    printf("%d * %d = %d\n", a, b,  ( { int _a = a+1; _a * b; } ) );

    return 0;

How to send Basic Auth with axios

The solution given by luschn and pillravi works fine unless you receive a Strict-Transport-Security header in the response.

Adding withCredentials: true will solve that issue., {
    withCredentials: true,
    headers: {
      "Accept": "application/json",
      "Content-Type": "application/json"
    auth: {
      username: "USERNAME",
      password: "PASSWORD"
  }}).then(function(response) {
  }).catch(function(error) {
    console.log('Error on Authentication');

H2 database error: Database may be already in use: "Locked by another process"

answer for this question => Exception in thread "main" org.h2.jdbc.JdbcSQLException: Database may be already in use: "Locked by another process". Possible solutions: close all other connection(s); use the server mode [90020-161]

close all tab from your browser where open h2 database also Exit h2 engine from your pc

Android textview usage as label and value

You should implement a Custom List View, such that you define a Layout once and draw it for every row in the list view.

jQuery / Javascript code check, if not undefined

$.fn.attr(attributeName) returns the attribute value as string, or undefined when the attribute is not present.

Since "", and undefined are both falsy (evaluates to false when coerced to boolean) values in JavaScript, in this case I would write the check as below:

if (wlocation) { ... }

How to build an APK file in Eclipse?

For testing on a device, you can connect the device using USB and run from Eclipse just as an emulator.

If you need to distribute the app, then use the export feature:

alt text

alt text

Then follow instructions. You will have to create a key in the process.

Using CSS for a fade-in effect on page load

Method 1:

If you are looking for a self-invoking transition then you should use CSS 3 Animations. They aren't supported either, but this is exactly the kind of thing they were made for.


#test p {
    margin-top: 25px;
    font-size: 21px;
    text-align: center;

    -webkit-animation: fadein 2s; /* Safari, Chrome and Opera > 12.1 */
       -moz-animation: fadein 2s; /* Firefox < 16 */
        -ms-animation: fadein 2s; /* Internet Explorer */
         -o-animation: fadein 2s; /* Opera < 12.1 */
            animation: fadein 2s;

@keyframes fadein {
    from { opacity: 0; }
    to   { opacity: 1; }

/* Firefox < 16 */
@-moz-keyframes fadein {
    from { opacity: 0; }
    to   { opacity: 1; }

/* Safari, Chrome and Opera > 12.1 */
@-webkit-keyframes fadein {
    from { opacity: 0; }
    to   { opacity: 1; }

/* Internet Explorer */
@-ms-keyframes fadein {
    from { opacity: 0; }
    to   { opacity: 1; }

/* Opera < 12.1 */
@-o-keyframes fadein {
    from { opacity: 0; }
    to   { opacity: 1; }


Browser Support

All modern browsers and Internet Explorer 10 (and later):

Method 2:

Alternatively, you can use jQuery (or plain JavaScript; see the third code block) to change the class on load:


$("#test p").addClass("load");?


#test p {
    opacity: 0;
    font-size: 21px;
    margin-top: 25px;
    text-align: center;

    -webkit-transition: opacity 2s ease-in;
       -moz-transition: opacity 2s ease-in;
        -ms-transition: opacity 2s ease-in;
         -o-transition: opacity 2s ease-in;
            transition: opacity 2s ease-in;

#test p.load {
    opacity: 1;

Plain JavaScript (not in the demo)

document.getElementById("test").children[0].className += " load";


Browser Support

All modern browsers and Internet Explorer 10 (and later):

Method 3:

Or, you can use the method that .Mail uses:


$("#test p").delay(1000).animate({ opacity: 1 }, 700);?


#test p {
    opacity: 0;
    font-size: 21px;
    margin-top: 25px;
    text-align: center;


Browser Support

jQuery 1.x: All modern browsers and Internet Explorer 6 (and later):
jQuery 2.x: All modern browsers and Internet Explorer 9 (and later):

This method is the most cross-compatible as the target browser does not need to support CSS 3 transitions or animations.

How do I obtain the frequencies of each value in an FFT?

The first bin in the FFT is DC (0 Hz), the second bin is Fs / N, where Fs is the sample rate and N is the size of the FFT. The next bin is 2 * Fs / N. To express this in general terms, the nth bin is n * Fs / N.

So if your sample rate, Fs is say 44.1 kHz and your FFT size, N is 1024, then the FFT output bins are at:

  0:   0 * 44100 / 1024 =     0.0 Hz
  1:   1 * 44100 / 1024 =    43.1 Hz
  2:   2 * 44100 / 1024 =    86.1 Hz
  3:   3 * 44100 / 1024 =   129.2 Hz
  4: ...
  5: ...
511: 511 * 44100 / 1024 = 22006.9 Hz

Note that for a real input signal (imaginary parts all zero) the second half of the FFT (bins from N / 2 + 1 to N - 1) contain no useful additional information (they have complex conjugate symmetry with the first N / 2 - 1 bins). The last useful bin (for practical aplications) is at N / 2 - 1, which corresponds to 22006.9 Hz in the above example. The bin at N / 2 represents energy at the Nyquist frequency, i.e. Fs / 2 ( = 22050 Hz in this example), but this is in general not of any practical use, since anti-aliasing filters will typically attenuate any signals at and above Fs / 2.

How can I setup & run PhantomJS on Ubuntu?

You can get up and running without sudo or npm. Simply download, extract, and add to path.

This has the added advantage of easy backup if you are in the habit of backing up your entire home folder which I highly recommend. This also works with any version of Linux.

?  cd ~
?  wget
?  mkdir phantomjs
?  tar xjf phantomjs-2.1.1-linux-x86_64.tar.bz2 -C phantomjs
?  echo 'export PATH="$PATH:$HOME/phantomjs/bin"' >> .profile
?  source .profile
?  phantomjs -v

The disadvantages are:

  1. You will need to manually upgrade
  2. Other users will not have access to this.

You could use a very simple shell script for installing/upgrading


printf "Downloading PhantomJS $VERSION...\n"
wget "$VERSION-linux-x86_64.tar.bz2"

printf "Extracting PhantomJS $VERSION to ~/phantomjs...\n"
mkdir ~/phantomjs
tar xjf phantomjs-$VERSION-linux-x86_64.tar.bz2 -C ~/phantomjs

printf "Done! Make sure $HOME/phantomjs/bin is in your path.\n"

Or in a Dockerfile

# Download and setup PhantomJS
RUN curl -fSL "$PHANTOMJS_VERSION-linux-x86_64.tar.bz2" -o /tmp/phantomjs.tar.bz2 && \
  mkdir ~/phantomjs && \
  tar xjf /tmp/phantomjs.tar.bz2 -C ~/phantomjs && \
  rm /tmp/phantomjs.tar.bz2
ENV PATH /home/$USERNAME/phantomjs/bin:$PATH

MySQL "incorrect string value" error when save unicode string in Django

You can change the collation of your text field to UTF8_general_ci and the problem will be solved.

Notice, this cannot be done in Django.

Where to find the complete definition of off_t type?

Since this answer still gets voted up, I want to point out that you should almost never need to look in the header files. If you want to write reliable code, you're much better served by looking in the standard. A better question than "how is off_t defined on my machine" is "how is off_t defined by the standard?". Following the standard means that your code will work today and tomorrow, on any machine.

In this case, off_t isn't defined by the C standard. It's part of the POSIX standard, which you can browse here.

Unfortunately, off_t isn't very rigorously defined. All I could find to define it is on the page on sys/types.h:

blkcnt_t and off_t shall be signed integer types.

This means that you can't be sure how big it is. If you're using GNU C, you can use the instructions in the answer below to ensure that it's 64 bits. Or better, you can convert to a standards defined size before putting it on the wire. This is how projects like Google's Protocol Buffers work (although that is a C++ project).

So, I think "where do I find the definition in my header files" isn't the best question. But, for completeness here's the answer:

On my machine (and most machines using glibc) you'll find the definition in bits/types.h (as a comment says at the top, never directly include this file), but it's obscured a bit in a bunch of macros. An alternative to trying to unravel them is to look at the preprocessor output:

#include <stdio.h>
#include <sys/types.h>

int main(void) {
  off_t blah;

  return 0;

And then:

$ gcc -E sizes.c  | grep __off_t
typedef long int __off_t;

However, if you want to know the size of something, you can always use the sizeof() operator.

Edit: Just saw the part of your question about the __. This answer has a good discussion. The key point is that names starting with __ are reserved for the implementation (so you shouldn't start your own definitions with __).

How to use the priority queue STL for objects?

A priority queue is an abstract data type that captures the idea of a container whose elements have "priorities" attached to them. An element of highest priority always appears at the front of the queue. If that element is removed, the next highest priority element advances to the front.

The C++ standard library defines a class template priority_queue, with the following operations:

push: Insert an element into the prioity queue.

top: Return (without removing it) a highest priority element from the priority queue.

pop: Remove a highest priority element from the priority queue.

size: Return the number of elements in the priority queue.

empty: Return true or false according to whether the priority queue is empty or not.

The following code snippet shows how to construct two priority queues, one that can contain integers and another one that can contain character strings:

#include <queue>

priority_queue<int> q1;
priority_queue<string> q2;

The following is an example of priority queue usage:

#include <string>
#include <queue>
#include <iostream>

using namespace std;  // This is to make available the names of things defined in the standard library.

int main()
    piority_queue<string> pq; // Creates a priority queue pq to store strings, and initializes the queue to be empty.

    pq.push("the quick");
    pq.push("jumped over");
    pq.push("the lazy dog");

    // The strings are ordered inside the priority queue in lexicographic (dictionary) order:
    // "fox", "jumped over", "the lazy dog", "the quick"
    //  The lowest priority string is "fox", and the highest priority string is "the quick"

    while (!pq.empty()) {
       cout << << endl;  // Print highest priority string
       pq.pop();                    // Remmove highest priority string

    return 0;

The output of this program is:

the quick
the lazy dog
jumped over

Since a queue follows a priority discipline, the strings are printed from highest to lowest priority.

Sometimes one needs to create a priority queue to contain user defined objects. In this case, the priority queue needs to know the comparison criterion used to determine which objects have the highest priority. This is done by means of a function object belonging to a class that overloads the operator (). The overloaded () acts as < for the purpose of determining priorities. For example, suppose we want to create a priority queue to store Time objects. A Time object has three fields: hours, minutes, seconds:

struct Time {
    int h; 
    int m; 
    int s;

class CompareTime {
    bool operator()(Time& t1, Time& t2) // Returns true if t1 is earlier than t2
       if (t1.h < t2.h) return true;
       if (t1.h == t2.h && t1.m < t2.m) return true;
       if (t1.h == t2.h && t1.m == t2.m && t1.s < t2.s) return true;
       return false;

A priority queue to store times according the the above comparison criterion would be defined as follows:

priority_queue<Time, vector<Time>, CompareTime> pq;

Here is a complete program:

#include <iostream>
#include <queue>
#include <iomanip>

using namespace std;

struct Time {
    int h; // >= 0
    int m; // 0-59
    int s; // 0-59

class CompareTime {
    bool operator()(Time& t1, Time& t2)
       if (t1.h < t2.h) return true;
       if (t1.h == t2.h && t1.m < t2.m) return true;
       if (t1.h == t2.h && t1.m == t2.m && t1.s < t2.s) return true;
       return false;

int main()
    priority_queue<Time, vector<Time>, CompareTime> pq;

    // Array of 4 time objects:

    Time t[4] = { {3, 2, 40}, {3, 2, 26}, {5, 16, 13}, {5, 14, 20}};

    for (int i = 0; i < 4; ++i)

    while (! pq.empty()) {
       Time t2 =;
       cout << setw(3) << t2.h << " " << setw(3) << t2.m << " " <<
       setw(3) << t2.s << endl;

    return 0;

The program prints the times from latest to earliest:

5  16  13
5  14  20
3   2  40
3   2  26

If we wanted earliest times to have the highest priority, we would redefine CompareTime like this:

class CompareTime {
    bool operator()(Time& t1, Time& t2) // t2 has highest prio than t1 if t2 is earlier than t1
       if (t2.h < t1.h) return true;
       if (t2.h == t1.h && t2.m < t1.m) return true;
       if (t2.h == t1.h && t2.m == t1.m && t2.s < t1.s) return true;
       return false;

Detecting value change of input[type=text] in jQuery

Use this:

It handles all the ways to change the input, including content menu (Using the mouse)

How to limit the number of selected checkboxes?

If you want to uncheck the checkbox that you have selected first under the condition of 3 checkboxes allowed. With vanilla javascript; you need to assign onclick = "checking(this)" in your html input checkbox

var queue = [];
function checking(id){
   if (queue.length===3){
    queue[0].checked = false

Setting PayPal return URL and making it auto return?

I think that the idea of setting the Auto Return values as described above by Kevin is a bit strange!

Say, for example, that you have a number of websites that use the same PayPal account to handle your payments, or say that you have a number of sections in one website that perform different purchasing tasks, and require different return-addresses when the payment is completed. If I put a button on my page as described above in the 'Sample form using PHP for direct payments' section, you can see that there is a line there:

input type="hidden" name="return" value=""

where you set the individual return value. Why does it have to be set generally, in the profile section as well?!?!

Also, because you can only set one value in the Profile Section, it means (AFAIK) that you cannot use the Auto Return on a site with multiple actions.

Comments please??

Attach parameter to button.addTarget action in Swift

For Swift 2.X and above


What's the Use of '\r' escape sequence?

As amaud576875 said, the \r escape sequence signifies a carriage-return, similar to pressing the Enter key. However, I'm not sure how you get "o world"; you should (and I do) get "my first hello world" and then a new line. Depending on what operating system you're using (I'm using Mac) you might want to use a \n instead of a \r.

How to push both value and key into PHP array

I wonder why the simplest method hasn't been posted yet:

$arr = ['company' => 'Apple', 'product' => 'iPhone'];
$arr += ['version' => 8];

How to perform OR condition in django queryset?

Both options are already mentioned in the existing answers:

from django.db.models import Q
q1 = User.objects.filter(Q(income__gte=5000) | Q(income__isnull=True))


q2 = User.objects.filter(income__gte=5000) | User.objects.filter(income__isnull=True)

However, there seems to be some confusion regarding which one is to prefer.

The point is that they are identical on the SQL level, so feel free to pick whichever you like!

The Django ORM Cookbook talks in some detail about this, here is the relevant part:

queryset = User.objects.filter(
    ) | User.objects.filter(

leads to

In [5]: str(queryset.query)
Out[5]: 'SELECT "auth_user"."id", "auth_user"."password", "auth_user"."last_login",
"auth_user"."is_superuser", "auth_user"."username", "auth_user"."first_name",
"auth_user"."last_name", "auth_user"."email", "auth_user"."is_staff",
"auth_user"."is_active", "auth_user"."date_joined" FROM "auth_user"
WHERE ("auth_user"."first_name"::text LIKE R% OR "auth_user"."last_name"::text LIKE D%)'


qs = User.objects.filter(Q(first_name__startswith='R') | Q(last_name__startswith='D'))

leads to

In [9]: str(qs.query)
Out[9]: 'SELECT "auth_user"."id", "auth_user"."password", "auth_user"."last_login",
 "auth_user"."is_superuser", "auth_user"."username", "auth_user"."first_name",
  "auth_user"."last_name", "auth_user"."email", "auth_user"."is_staff",
  "auth_user"."is_active", "auth_user"."date_joined" FROM "auth_user"
  WHERE ("auth_user"."first_name"::text LIKE R% OR "auth_user"."last_name"::text LIKE D%)'

source: django-orm-cookbook

How to remove all numbers from string?

For Western Arabic numbers (0-9):

$words = preg_replace('/[0-9]+/', '', $words);

For all numerals including Western Arabic (e.g. Indian):

$words = '????';
$words = preg_replace('/\d+/u', '', $words);
var_dump($words); // string(0) ""
  • \d+ matches multiple numerals.
  • The modifier /u enables unicode string treatment. This modifier is important, otherwise the numerals would not match.

Can Selenium WebDriver open browser windows silently in the background?

If you are using Ubuntu (Gnome), one simple workaround is to install Gnome extension auto-move-window:

Then set the browser (eg. Chrome) to another workspace (eg. Workspace 2). The browser will silently run in other workspace and not bother you anymore. You can still use Chrome in your workspace without any interruption.

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

It's a shortened "N-tuple" (like in quadruple, quintuple etc.)

It's a row of a rowset taken as a whole.

If you issue:

SELECT  col1, col2
FROM    mytable

, whole result will be a ROWSET, and each pair of col1, col2 will be a tuple.

Some databases can work with a tuple as a whole.

Like, you can do this:

SELECT  col1, col2
FROM    mytable
WHERE   (col1, col2) =
        SELECT  col3, col4
        FROM    othertable

, which checks that a whole tuple from one rowset matches a whole tuple from another rowset.

How in node to split string by newline ('\n')?

If the file is native to your system (certainly no guarantees of that), then Node can help you out:

var os = require('os');


This is usually more useful for constructing output strings from Node though, for platform portability.

Get the current cell in Excel VB

I realize this doesn't directly apply from the title of the question, However some ways to deal with a variable range could be to select the range each time the code runs -- especially if you are interested in a user-selected range. If you are interested in that option, you can use the Application.InputBox (official documentation page here). One of the optional variables is 'type'. If the type is set equal to 8, the InputBox also has an excel-style range selection option. An example of how to use it in code would be:

Dim rng as Range
Set rng = Application.InputBox(Prompt:= "Please select a range", Type:=8)


If you assign the InputBox value to a none-range variable (without the Set keyword), instead of the ranges, the values from the ranges will be assigned, as in the code below (although selecting multiple ranges in this situation may require the values to be assigned to a variant):

Dim str as String
str = Application.InputBox(Prompt:= "Please select a range", Type:=8)

How to list installed packages from a given repo using yum

On newer versions of yum, this information is stored in the "yumdb" when the package is installed. This is the only 100% accurate way to get the information, and you can use:

yumdb search from_repo repoid

(or repoquery and grep -- don't grep yum output). However the command "find-repos-of-install" was part of yum-utils for a while which did the best guess without that information:

As floyd said, a lot of repos. include a unique "dist" tag in their release, and you can look for that ... however from what you said, I guess that isn't the case for you?

How to overwrite styling in Twitter Bootstrap

If you want to overwrite any css in bootstrap use !important

Let's say here is the page header class in bootstrap which have 40px margin on top, my client don't like it and he want it to be 15 on top and 10 on bottom only

.page-header {
    border-bottom: 1px solid #EEEEEE;
    margin: 40px 0 20px;
    padding-bottom: 9px;

So I added on class in my site.css file with the same name like this

    padding-bottom: 9px;
    margin: 15px 0 10px 0px !important;

Note the !important with my margin, which will overwrite the margin of bootstarp page-header class margin.

Deserialize JSON array(or list) in C#

I was having the similar issue and solved by understanding the Classes in C#

I want to read following JSON string :

        "resultList": [
                "channelType": "",
                "duration": "2:29:30",
                "episodeno": 0,
                "genre": "Drama",
                "genreList": [
                "genres": [
                        "personName": "Drama"
                "id": 1204,
                "language": "Hindi",
                "name": "The Great Target",
                "productId": 1204,
                "productMasterId": 1203,
                "productMasterName": "The Great Target",
                "productName": "The Great Target",
                "productTypeId": 1,
                "productTypeName": "Movie",
                "rating": 3,
                "releaseyear": "2005",
                "showGoodName": "Movies ",
                "views": 8333
                "channelType": "",
                "duration": "2:30:30",
                "episodeno": 0,
                "genre": "Romance",
                "genreList": [
                "genres": [
                        "personName": "Romance"
                "id": 1144,
                "language": "Hindi",
                "name": "Mere Sapnon Ki Rani",
                "productId": 1144,
                "productMasterId": 1143,
                "productMasterName": "Mere Sapnon Ki Rani",
                "productName": "Mere Sapnon Ki Rani",
                "productTypeId": 1,
                "productTypeName": "Movie",
                "rating": 3,
                "releaseyear": "1997",
                "showGoodName": "Movies ",
                "views": 6482
                "channelType": "",
                "duration": "2:34:07",
                "episodeno": 0,
                "genre": "Drama",
                "genreList": [
                "genres": [
                        "personName": "Drama"
                "id": 1520,
                "language": "Telugu",
                "name": "Satyameva Jayathe",
                "productId": 1520,
                "productMasterId": 1519,
                "productMasterName": "Satyameva Jayathe",
                "productName": "Satyameva Jayathe",
                "productTypeId": 1,
                "productTypeName": "Movie",
                "rating": 3,
                "releaseyear": "2004",
                "showGoodName": "Movies ",
                "views": 9910
        "resultSize": 1171,
        "pageIndex": "1"

My c# code looks like following

First, Class3.cs page created in APP_Code folder of Web application

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Collections;
using System.Text;
using System.IO;
using System.Web.Script.Serialization;
using System.Collections.Generic;

/// <summary>
/// Summary description for Class3
/// </summary>
public class Class3

    public List<ListWrapper_Main> ResultList_Main { get; set; }

    public class ListWrapper_Main
        public List<ListWrapper> ResultList { get; set; }

        public string resultSize { get; set; }
        public string pageIndex { get; set; }

    public class ListWrapper
        public string channelType { get; set; }
        public string duration { get; set; }
        public int episodeno { get; set; }
        public string genre { get; set; }
        public string[] genreList { get; set; }
        public List<genres_cls> genres { get; set; }
        public int id { get; set; }
        public string imageUrl { get; set; }
        //public string imageurl { get; set; }
        public string language { get; set; }
        public string name { get; set; }
        public int productId { get; set; }
        public int productMasterId { get; set; }
        public string productMasterName { get; set; }
        public string productName { get; set; }
        public int productTypeId { get; set; }
        public string productTypeName { get; set; }
        public decimal rating { get; set; }
        public string releaseYear { get; set; }
        //public string releaseyear { get; set; }
        public string showGoodName { get; set; }
        public string views { get; set; }
    public class genres_cls
        public string personName { get; set; }


Then, Browser page that reads the string/JSON string listed above and displays/Deserialize the JSON objects and displays the data

JavaScriptSerializer ser = new JavaScriptSerializer();

        string final_sb = sb.ToString();

        List<Class3.ListWrapper_Main> movieInfos = ser.Deserialize<List<Class3.ListWrapper_Main>>(final_sb.ToString());

        foreach (var itemdetail in movieInfos)

            foreach (var itemdetail2 in itemdetail.ResultList)
                Response.Write("channelType=" + itemdetail2.channelType + "<br/>");
                Response.Write("duration=" + itemdetail2.duration + "<br/>");
                Response.Write("episodeno=" + itemdetail2.episodeno + "<br/>");
                Response.Write("genre=" + itemdetail2.genre + "<br/>");

                string[] genreList_arr = itemdetail2.genreList;
                for (int i = 0; i < genreList_arr.Length; i++)
                    Response.Write("genreList1=" + genreList_arr[i].ToString() + "<br>");

                foreach (var genres1 in itemdetail2.genres)
                    Response.Write("genres1=" + genres1.personName + "<br>");

                Response.Write("id=" + + "<br/>");
                Response.Write("imageUrl=" + itemdetail2.imageUrl + "<br/>");
                //Response.Write("imageurl=" + itemdetail2.imageurl + "<br/>");
                Response.Write("language=" + itemdetail2.language + "<br/>");
                Response.Write("name=" + + "<br/>");
                Response.Write("productId=" + itemdetail2.productId + "<br/>");
                Response.Write("productMasterId=" + itemdetail2.productMasterId + "<br/>");
                Response.Write("productMasterName=" + itemdetail2.productMasterName + "<br/>");
                Response.Write("productName=" + itemdetail2.productName + "<br/>");
                Response.Write("productTypeId=" + itemdetail2.productTypeId + "<br/>");
                Response.Write("productTypeName=" + itemdetail2.productTypeName + "<br/>");
                Response.Write("rating=" + itemdetail2.rating + "<br/>");
                Response.Write("releaseYear=" + itemdetail2.releaseYear + "<br/>");
                //Response.Write("releaseyear=" + itemdetail2.releaseyear + "<br/>");
                Response.Write("showGoodName=" + itemdetail2.showGoodName + "<br/>");
                Response.Write("views=" + itemdetail2.views + "<br/><br>");
                //Response.Write("resultSize" + itemdetail2.resultSize + "<br/>");
                //  Response.Write("pageIndex" + itemdetail2.pageIndex + "<br/>");


            Response.Write("resultSize=" + itemdetail.resultSize + "<br/><br>");
            Response.Write("pageIndex=" + itemdetail.pageIndex + "<br/><br>");


'sb' is the actual string, i.e. JSON string of data mentioned very first on top of this reply

This is basically - web application c# code....

N joy...

ElasticSearch, Sphinx, Lucene, Solr, Xapian. Which fits for which usage?

My sphinx.conf

source post_source 
    type = mysql

    sql_host = localhost
    sql_user = ***
    sql_pass = ***
    sql_db =   ***
    sql_port = 3306

    sql_query_pre = SET NAMES utf8
    # query before fetching rows to index

    sql_query = SELECT *, id AS pid, CRC32(safetag) as safetag_crc32 FROM hb_posts

    sql_attr_uint = pid  
    # pid (as 'sql_attr_uint') is necessary for sphinx
    # this field must be unique

    # that is why I like sphinx
    # you can store custom string fields into indexes (memory) as well
    sql_field_string = title
    sql_field_string = slug
    sql_field_string = content
    sql_field_string = tags

    sql_attr_uint = category
    # integer fields must be defined as sql_attr_uint

    sql_attr_timestamp = date
    # timestamp fields must be defined as sql_attr_timestamp

    sql_query_info_pre = SET NAMES utf8
    # if you need unicode support for sql_field_string, you need to patch the source
    # this param. is not supported natively

    sql_query_info = SELECT * FROM my_posts WHERE id = $id

index posts 
    source = post_source
    # source above

    path = /var/data/posts
    # index location

    charset_type = utf-8

Test script:


    require "sphinxapi.php";

    $safetag = $_GET["my_post_slug"];
//  $safetag = preg_replace("/[^a-z0-9\-_]/i", "", $safetag);

    $conf = getMyConf();

    $cl = New SphinxClient();

    $cl->SetServer($conf["server"], $conf["port"]);

    # set search params

    $cl->setLimits(0, 1, 1); 
    # looking for the post (not searching a keyword)

    $cl->SetFilter("safetag_crc32", array(crc32($safetag)));

    # fetch results
    $post = $cl->Query(null, "post_1");

    echo "<pre>";
    echo "</pre>";

Sample result:

[array] => 
  "id" => 123,
  "title" => "My post title.",
  "content" => "My <p>post</p> content.",
   [ and other fields ]

Sphinx query time:

0.001 sec.

Sphinx query time (1k concurrent):

=> 0.346 sec. (average)
=> 0.340 sec. (average of last 10 query)

MySQL query time:

"SELECT * FROM hb_posts WHERE id = 123;"
=> 0.001 sec.

MySQL query time (1k concurrent):

"SELECT * FROM my_posts WHERE id = 123;" 
=> 1.612 sec. (average)
=> 1.920 sec. (average of last 10 query)

Convert timestamp to readable date/time PHP

$epoch = 1483228800;
$dt = new DateTime("@$epoch");  // convert UNIX timestamp to PHP DateTime
echo $dt->format('Y-m-d H:i:s'); // output = 2017-01-01 00:00:00

In the examples above "r" and "Y-m-d H:i:s" are PHP date formats, other examples:

Format Output

r              -----    Wed, 15 Mar 2017 12:00:00 +0100 (RFC 2822 date)
c              -----    2017-03-15T12:00:00+01:00 (ISO 8601 date)
M/d/Y          -----    Mar/15/2017
d-m-Y          -----    15-03-2017
Y-m-d H:i:s    -----    2017-03-15 12:00:00

How to resolve the C:\fakepath?

Use file readers:

$(document).ready(function() {
        $("#input-file").change(function() {
            var length = this.files.length;
            if (!length) {
                return false;

    // Creating the function
    function useImage(img) {
        var file = img.files[0];
        var imagefile = file.type;
        var match = ["image/jpeg", "image/png", "image/jpg"];
        if (!((imagefile == match[0]) || (imagefile == match[1]) || (imagefile == match[2]))) {
            alert("Invalid File Extension");
        } else {
            var reader = new FileReader();
            reader.onload = imageIsLoaded;

        function imageIsLoaded(e) {
            $('div.withBckImage').css({ 'background-image': "url(" + + ")" });


Disable and later enable all table indexes in Oracle

If you're on Oracle 11g, you may also want to check out dbms_index_utl.

How to divide two columns?

Presumably, those columns are integer columns - which will be the reason as the result of the calculation will be of the same type.

e.g. if you do this:

SELECT 1 / 2

you will get 0, which is obviously not the real answer. So, convert the values to e.g. decimal and do the calculation based on that datatype instead.



gives 0.500000

Object comparison in JavaScript

Unfortunately there is no perfect way, unless you use _proto_ recursively and access all non-enumerable properties, but this works in Firefox only.

So the best I can do is to guess usage scenarios.

1) Fast and limited.

Works when you have simple JSON-style objects without methods and DOM nodes inside:

 JSON.stringify(obj1) === JSON.stringify(obj2) 

The ORDER of the properties IS IMPORTANT, so this method will return false for following objects:

 x = {a: 1, b: 2};
 y = {b: 2, a: 1};

2) Slow and more generic.

Compares objects without digging into prototypes, then compares properties' projections recursively, and also compares constructors.

This is almost correct algorithm:

function deepCompare () {
  var i, l, leftChain, rightChain;

  function compare2Objects (x, y) {
    var p;

    // remember that NaN === NaN returns false
    // and isNaN(undefined) returns true
    if (isNaN(x) && isNaN(y) && typeof x === 'number' && typeof y === 'number') {
         return true;

    // Compare primitives and functions.     
    // Check if both arguments link to the same object.
    // Especially useful on the step where we compare prototypes
    if (x === y) {
        return true;

    // Works in case when functions are created in constructor.
    // Comparing dates is a common scenario. Another built-ins?
    // We can even handle functions passed across iframes
    if ((typeof x === 'function' && typeof y === 'function') ||
       (x instanceof Date && y instanceof Date) ||
       (x instanceof RegExp && y instanceof RegExp) ||
       (x instanceof String && y instanceof String) ||
       (x instanceof Number && y instanceof Number)) {
        return x.toString() === y.toString();

    // At last checking prototypes as good as we can
    if (!(x instanceof Object && y instanceof Object)) {
        return false;

    if (x.isPrototypeOf(y) || y.isPrototypeOf(x)) {
        return false;

    if (x.constructor !== y.constructor) {
        return false;

    if (x.prototype !== y.prototype) {
        return false;

    // Check for infinitive linking loops
    if (leftChain.indexOf(x) > -1 || rightChain.indexOf(y) > -1) {
         return false;

    // Quick checking of one object being a subset of another.
    // todo: cache the structure of arguments[0] for performance
    for (p in y) {
        if (y.hasOwnProperty(p) !== x.hasOwnProperty(p)) {
            return false;
        else if (typeof y[p] !== typeof x[p]) {
            return false;

    for (p in x) {
        if (y.hasOwnProperty(p) !== x.hasOwnProperty(p)) {
            return false;
        else if (typeof y[p] !== typeof x[p]) {
            return false;

        switch (typeof (x[p])) {
            case 'object':
            case 'function':


                if (!compare2Objects (x[p], y[p])) {
                    return false;


                if (x[p] !== y[p]) {
                    return false;

    return true;

  if (arguments.length < 1) {
    return true; //Die silently? Don't know how to handle such case, please help...
    // throw "Need two or more arguments to compare";

  for (i = 1, l = arguments.length; i < l; i++) {

      leftChain = []; //Todo: this can be cached
      rightChain = [];

      if (!compare2Objects(arguments[0], arguments[i])) {
          return false;

  return true;

Known issues (well, they have very low priority, probably you'll never notice them):

  • objects with different prototype structure but same projection
  • functions may have identical text but refer to different closures

Tests: passes tests are from How to determine equality for two JavaScript objects?.

How do you pass view parameters when navigating from an action in JSF2?

You can do it using Primefaces like this :


How can I de-install a Perl module installed via `cpan`?

Since at the time of installing of any module it mainly put corresponding .pm files in respective directories. So if you want to remove module only for some testing purpose or temporarily best is to find the path where module is stored using perldoc -l <MODULE> and then simply move the module from there to some other location. This approach can also be tried as a more permanent solution but i am not aware of any negative consequences as i do it mainly for testing.

Unit Tests not discovered in Visual Studio 2017

For me was easier to create a new test project that works perfectly fine with Visual Studio 2017... and just copy the test files, add references, and NuGet packages as required.

enter image description here

sql: check if entry in table A exists in table B

The classical answer that works in almost every environment is

SELECT ID, Name, blah, blah

sometimes NOT EXISTS may be not implemented (not working).

Difference between int32, int, int32_t, int8 and int8_t

The _t data types are typedef types in the stdint.h header, while int is an in built fundamental data type. This make the _t available only if stdint.h exists. int on the other hand is guaranteed to exist.

How to run travis-ci locally

I wasn't able to use the answers here as-is. For starters, as noted, the Travis help document on running jobs locally has been taken down. All of the blog entries and articles I found are based on that. The new "debug" mode doesn't appeal to me because I want to avoid the queue times and the Travis infrastructure until I've got some confidence I have gotten somewhere with my changes.

In my case I'm updating a Puppet module and I'm not an expert in Puppet, nor particularly experienced in Ruby, Travis, or their ecosystems. But I managed to build a workable test image out of tips and ideas in this article and elsewhere, and by examining the Travis CI build logs pretty closely.

I was unable to find recent images matching the names in the CI logs (for example, I could find travisci/ci-sardonyx, but could not find anything with "xenial" or with the same build name). From the logs it appears images are now transferred via AMQP instead of a mechanism more familiar to me.

I was able to find an image travsci/ubuntu-ruby:16.04 which matches the OS I'm targeting for my particular case. It does not have all the components used in the Travis CI, so I built a new one based on this, with some components added to the image and others added in the container at runtime depending on the need.

So I can't offer a clear procedure, sorry. But what I did, essentially boiled down:

  1. Find a recent Travis CI image in Docker Hub matching your target OS as closely as possible.

  2. Clone the repository to a build directory, and launch the container with the build directory mounted as a volume, with the working directory set to the target volume

  3. Now the hard work: go through the Travis build log and set up the environment. In my case, this meant setting up RVM, and then using bundle to install the project's dependencies. RVM appeared to be already present in the Travis environment but I had to install it; everything else came from reproducing the commands in the build log.

  4. Run the tests.

  5. If the results don't match what you saw in the Travis CI logs, go back to (3) and see where to go.

  6. Optionally, create a reusable image.

  7. Dev and test locally and then push and hopefully your Travis results will be as expected.

I know this is not concrete and may be obvious, and your mileage will definitely vary, but hopefully this is of some use to somebody. The Dockerfile and a README for my image are on GitHub for reference.

Finding duplicate integers in an array and display how many times they occurred

int copt = 1;
int element = 0;
int[] array = { 1, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 5 };
for (int i = 0; i < array.Length; i++)
   for (int j = i + 1; j < array.Length - 1; j++)
       if (array[i] == array[j])
          element = array[i];

Console.WriteLine("the repeat element is {0} and it's appears {1} times ", element, copt);

// the output is the element is 3 and appears 9 times

Call JavaScript function on DropDownList SelectedIndexChanged Event:

First Method: (Tested)

Code in .aspx.cs:

 protected void Page_Load(object sender, EventArgs e)
        ddl.SelectedIndexChanged += new EventHandler(ddl_SelectedIndexChanged);
        if (!Page.IsPostBack)
            ddl.Attributes.Add("onchange", "CalcTotalAmt();");

    protected void ddl_SelectedIndexChanged(object sender, EventArgs e)
       //Your Code

JavaScript function: return true from your JS function

   function CalcTotalAmt() 
//Your Code

.aspx code:

<asp:DropDownList ID="ddl" runat="server"  AutoPostBack="true">
        <asp:ListItem Text="a" Value="a"></asp:ListItem>
         <asp:ListItem Text="b" Value="b"></asp:ListItem>

Second Method: (Tested)

Code in .aspx.cs:

protected void Page_Load(object sender, EventArgs e)
            if (Request.Params["__EVENTARGUMENT"] != null && Request.Params["__EVENTARGUMENT"].Equals("ddlchange"))
                ddl_SelectedIndexChanged(sender, e);
            if (!Page.IsPostBack)
                ddl.Attributes.Add("onchange", "CalcTotalAmt();");

        protected void ddl_SelectedIndexChanged(object sender, EventArgs e)
            //Your Code

JavaScript function: return true from your JS function

function CalcTotalAmt() {
         //Your Code

.aspx code:

<asp:DropDownList ID="ddl" runat="server"  AutoPostBack="true">
        <asp:ListItem Text="a" Value="a"></asp:ListItem>
         <asp:ListItem Text="b" Value="b"></asp:ListItem>

`require': no such file to load -- mkmf (LoadError)

You can use RVM(Ruby version manager) which helps in managing all versions of ruby on your machine , which is very helpful for you development (when migrating to unstable release to stable release )

or for Linux (ubuntu) go for sudo apt-get install ruby1.8-dev

then sudo gem install rails to verify it do rails -v it will show version on rails

after that you can install bundles (required gems for development)

Selecting multiple columns in a Pandas dataframe

You can use the pandas.DataFrame.filter method to either filter or reorder columns like this:

df1 = df.filter(['a', 'b'])

This is also very useful when you are chaining methods.

How to increase dbms_output buffer?

When buffer size gets full. There are several options you can try:

1) Increase the size of the DBMS_OUTPUT buffer to 1,000,000

2) Try filtering the data written to the buffer - possibly there is a loop that writes to DBMS_OUTPUT and you do not need this data.

3) Call ENABLE at various checkpoints within your code. Each call will clear the buffer.

DBMS_OUTPUT.ENABLE(NULL) will default to 20000 for backwards compatibility Oracle documentation on dbms_output

You can also create your custom output display.something like below snippets

create or replace procedure cust_output(input_string in varchar2 )

   out_string_in long default in_string; 
   string_lenth number; 
   loop_count number default 0; 


   str_len := length(out_string_in);

   while loop_count < str_len
      dbms_output.put_line( substr( out_string_in, loop_count +1, 255 ) ); 
      loop_count := loop_count +255; 
   end loop; 

Link -Ref :Alternative to dbms_output.putline @ By: Alexander

Use cell's color as condition in if statement (function)

I don't believe there's any way to get a cell's color from a formula. The closest you can get is the CELL formula, but (at least as of Excel 2003), it doesn't return the cell's color.

It would be pretty easy to implement with VBA:

Public Function myColor(r As Range) As Integer
    myColor = r.Interior.ColorIndex
End Function

Then in the worksheet:


Matplotlib color according to class labels

A simple solution is to assign color for each class. This way, we can control how each color is for each class. For example:

arr1 = [1, 2, 3, 4, 5]
arr2 = [2, 3, 3, 4, 4]
labl = [0, 1, 1, 0, 0]
color= ['red' if l == 0 else 'green' for l in labl]
plt.scatter(arr1, arr2, color=color)

How to convert integer into date object python?

import datetime

timestamp = datetime.datetime.fromtimestamp(1500000000)

print(timestamp.strftime('%Y-%m-%d %H:%M:%S'))

This will give the output:

2017-07-14 08:10:00

Generate .pem file used to set up Apple Push Notifications

it is very simple after exporting the Cert.p12 and key.p12, Please find below command for the generating 'apns' .pem file. ?

command to create apns-dev.pem from Cert.pem and Key.pem

openssl rsa -in Key.pem -out apns-dev-key-noenc.pem

cat Cert.pem apns-dev-key-noenc.pem > apns-dev.pem

Above command is useful for both Sandbox and Production.

how to print a string to console in c++

yes it's possible to print a string to the console.

#include "stdafx.h"
#include <string>
#include <iostream>

using namespace std;

int _tmain(int argc, _TCHAR* argv[])
    string strMytestString("hello world");
    cout << strMytestString;
    return 0;

stdafx.h isn't pertinent to the solution, everything else is.

How do I split a string by a multi-character delimiter in C#?

Example from the docs:

string source = "[stop]ONE[stop][stop]TWO[stop][stop][stop]THREE[stop][stop]";
string[] stringSeparators = new string[] {"[stop]"};
string[] result;

// ...
result = source.Split(stringSeparators, StringSplitOptions.None);

foreach (string s in result)
    Console.Write("'{0}' ", String.IsNullOrEmpty(s) ? "<>" : s);

Error:Execution failed for task ':app:processDebugResources'. > Could not delete folder "" in android studio

Try closing your text editor (maybe VS Code) and File Explorer and run the command again in terminal with admin permissions.

How to scroll the page when a modal dialog is longer than the screen?

Here is my demo of modal window that auto-resize to its content and starts scrolling when it does not fit the window.

Modal window demo (see comments in the HTML source code)

All done only with HTML and CSS - no JS required to display and resize the modal window (but you still need it to display the window of course - in new version you don't need JS at all).

Update (more demos):

The point is to have outer and inner DIVs where the outer one defines the fixed position and the inner creates the scrolling. (In the demo there are actually more DIVs to make them look like an actual modal window.)

        #modal {
            position: fixed;
            transform: translate(0,0);
            width: auto; left: 0; right: 0;
            height: auto; top: 0; bottom: 0;
            z-index: 990; /* display above everything else */
            padding: 20px; /* create padding for inner window - page under modal window will be still visible */

        #modal .outer {
            box-sizing: border-box; -moz-box-sizing: border-box; -webkit-box-sizing: border-box; -o-box-sizing: border-box;
            width: 100%;
            height: 100%;
            position: relative;
            z-index: 999;

        #modal .inner {
            box-sizing: border-box; -moz-box-sizing: border-box; -webkit-box-sizing: border-box; -o-box-sizing: border-box;
            width: 100%;
            height: auto;       /* allow to fit content (if smaller)... */
            max-height: 100%;   /* ... but make sure it does not overflow browser window */

            /* allow vertical scrolling if required */
            overflow-x: hidden;
            overflow-y: auto;

            /* definition of modal window layout */
            background: #ffffff;
            border: 2px solid #222222;
            border-radius: 16px; /* some nice (modern) round corners */
            padding: 16px;       /* make sure inner elements does not overflow round corners */

How to center absolute div horizontally using CSS?

Here is a link please use this to make the div in the center if position is absolute.


<div class="bar"></div>


  border-top:4px solid red;

Example jsfiddle

How to create a sleep/delay in nodejs that is Blocking?

With ECMA script 2017 (supported by Node 7.6 and above), it becomes a one-liner:

function sleep(millis) {
  return new Promise(resolve => setTimeout(resolve, millis));

// Usage in async function
async function test() {
  await sleep(1000)
  console.log("one second has elapsed")

// Usage in normal function
function test2() {
  sleep(1000).then(() => {
    console.log("one second has elapsed")

How do I get a list of files in a directory in C++?

You have to use operating system calls (e.g. the Win32 API) or a wrapper around them. I tend to use Boost.Filesystem as it is superior interface compared to the mess that is the Win32 API (as well as being cross platform).

If you are looking to use the Win32 API, Microsoft has a list of functions and examples on msdn.

How do I list one filename per output line in Linux?

Ls is designed for human consumption, and you should not parse its output.

In shell scripts, there are a few cases where parsing the output of ls does work is the simplest way of achieving the desired effect. Since ls might mangle non-ASCII and control characters in file names, these cases are a subset of those that do not require obtaining a file name from ls.

In python, there is absolutely no reason to invoke ls. Python has all of ls's functionality built-in. Use os.listdir to list the contents of a directory and os.stat or os to obtain file metadata. Other functions in the os modules are likely to be relevant to your problem as well.

If you're accessing remote files over ssh, a reasonably robust way of listing file names is through sftp:

echo ls -1 | sftp remote-site:dir

This prints one file name per line, and unlike the ls utility, sftp does not mangle nonprintable characters. You will still not be able to reliably list directories where a file name contains a newline, but that's rarely done (remember this as a potential security issue, not a usability issue).

In python (beware that shell metacharacters must be escapes in remote_dir):

command_line = "echo ls -1 | sftp " + remote_site + ":" + remote_dir
remote_files = os.popen(command_line).read().split("\n")

For more complex interactions, look up sftp's batch mode in the documentation.

On some systems (Linux, Mac OS X, perhaps some other unices, but definitely not Windows), a different approach is to mount a remote filesystem through ssh with sshfs, and then work locally.

JavaScript seconds to time string with format hh:mm:ss

            var t = wachttijd_sec; // your seconds
            var hour = Math.floor(t/3600);
            if(hour < 10){
                hour = '0'+hour;
            var time = hour+':'+('0'+Math.floor(t/60)%60).slice(-2)+':'+('0' + t % 60).slice(-2);
            //would output: 00:00:00 > +100:00:00

keeps counten down even if more then 24 hours

Does Android keep the .apk files? if so where?

As opposed to what's written on the chosen answer, you don't need root and it is possible to get the APKs of the installed apps, which is how I've done it on my app (here). Example:

List<PackageInfo> packages=getPackageManager().getInstalledPackages(0);

Then, for each of the items of the list, you can access packageInfo.applicationInfo.sourceDir, which is the full path of the APK of the installed app.

error: request for member '..' in '..' which is of non-class type

Foo foo2();

change to

Foo foo2;

You get the error because compiler thinks of

Foo foo2()

as of function declaration with name 'foo2' and the return type 'Foo'.

But in that case If we change to Foo foo2 , the compiler might show the error " call of overloaded ‘Foo()’ is ambiguous".

Object cannot be cast from DBNull to other types

I'm thinking that your output parameter is coming back with a DBNull value. Add a check for that like this

var outputParam = dataAccCom.GetParameterValue(IDbCmd, "op_Id");
if(!(outputParam is DBNull))
     DataTO.Id = Convert.ToInt64(outputParam);

CMake: How to build external projects and include their targets

This post has a reasonable answer:

cmake_minimum_required(VERSION 2.8.2)

project(googletest-download NONE)

  GIT_TAG           master
  SOURCE_DIR        "${CMAKE_BINARY_DIR}/googletest-src"
  BINARY_DIR        "${CMAKE_BINARY_DIR}/googletest-build"
  TEST_COMMAND      ""


# Download and unpack googletest at configure time
  WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/googletest-download )
execute_process(COMMAND ${CMAKE_COMMAND} --build .
  WORKING_DIRECTORY ${CMAKE_BINARY_DIR}/googletest-download )

# Prevent GoogleTest from overriding our compiler/linker options
# when building with Visual Studio
set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)

# Add googletest directly to our build. This adds
# the following targets: gtest, gtest_main, gmock
# and gmock_main

# The gtest/gmock targets carry header search path
# dependencies automatically when using CMake 2.8.11 or
# later. Otherwise we have to add them here ourselves.

# Now simply link your own targets against gtest, gmock,
# etc. as appropriate

However it does seem quite hacky. I'd like to propose an alternative solution - use Git submodules.

cd MyProject/dependencies/gtest
git submodule add
cd googletest
git checkout release-1.8.0
cd ../../..
git add *
git commit -m "Add googletest"

Then in MyProject/dependencies/gtest/CMakeList.txt you can do something like:

cmake_minimum_required(VERSION 3.3)

if(TARGET gtest) # To avoid diamond dependencies; may not be necessary depending on you project.


I haven't tried this extensively yet but it seems cleaner.

Edit: There is a downside to this approach: The subdirectory might run install() commands that you don't want. This post has an approach to disable them but it was buggy and didn't work for me.

Edit 2: If you use add_subdirectory("googletest" EXCLUDE_FROM_ALL) it seems means the install() commands in the subdirectory aren't used by default.

How do I redirect output to a variable in shell?

Use the $( ... ) construct:

hash=$(genhash --use-ssl -s $IP -p 443 --url $URL | grep MD5 | grep -c $MD5)

Limit Get-ChildItem recursion depth

Try this function:

Function Get-ChildItemToDepth {
        [String]$Path = $PWD,
        [String]$Filter = "*",
        [Byte]$ToDepth = 255,
        [Byte]$CurrentDepth = 0,

    If ($DebugMode) {
        $DebugPreference = "Continue"

    Get-ChildItem $Path | %{
        $_ | ?{ $_.Name -Like $Filter }

        If ($_.PsIsContainer) {
            If ($CurrentDepth -le $ToDepth) {

                # Callback to this function
                Get-ChildItemToDepth -Path $_.FullName -Filter $Filter `
                  -ToDepth $ToDepth -CurrentDepth $CurrentDepth
            Else {
                Write-Debug $("Skipping GCI for Folder: $($_.FullName) " + `
                  "(Why: Current depth $CurrentDepth vs limit depth $ToDepth)")


Malformed String ValueError ast.literal_eval() with String representation of Tuple

Use eval() instead of ast.literal_eval() if the input is trusted (which it is in your case).

raw_data ='\n')
for a in raw_data : 
    print a

This works for me in Python 3.6.0

Handling errors in Promise.all

You can always wrap your promise returning functions in a way that they catches failure and returning instead an agreed value (e.g. error.message), so the exception won't roll all the way up to the Promise.all function and disable it.

async function resetCache(ip) {

    try {

        const response = await axios.get(`http://${ip}/resetcache`);
        return response;

    }catch (e) {

        return {status: 'failure', reason: 'e.message'};


Finding Number of Cores in Java

This works on Windows with Cygwin installed:


What does request.getParameter return?

String onevalue;   

How to align an image dead center with bootstrap

Twitter bootstrap has a class that centers: .pagination-centered

It worked for me to do:

<div class="row-fluid">
   <div class="span12 pagination-centered"><img src="header.png" alt="header" /></div>

The css for the class is:

.pagination-centered {
  text-align: center;

Convert DataFrame column type from string to datetime, dd/mm/yyyy format

If you have a mixture of formats in your date, don't forget to set infer_datetime_format=True to make life easier.

df['date'] = pd.to_datetime(df['date'], infer_datetime_format=True)

Source: pd.to_datetime

or if you want a customized approach:

def autoconvert_datetime(value):
    formats = ['%m/%d/%Y', '%m-%d-%y']  # formats to try
    result_format = '%d-%m-%Y'  # output format
    for dt_format in formats:
            dt_obj = datetime.strptime(value, dt_format)
            return dt_obj.strftime(result_format)
        except Exception as e:  # throws exception when format doesn't match
    return value  # let it be if it doesn't match

df['date'] = df['date'].apply(autoconvert_datetime)

Bootstrap-select - how to fire event on change

When Bootstrap Select initializes, it'll build a set of custom divs that run alongside the original <select> element and will typically synchronize state between the two input mechanisms.

BS Select Elements

Which is to say that one way to handle events on bootstrap select is to listen for events on the original select that it modifies, regardless of who updated it.

Solution 1 - Native Events

Just listen for a change event and get the selected value using javascript or jQuery like this:

$('select').on('change', function(e){

*NOTE: As with any script reliant on the DOM, make sure you wait for the DOM ready event before executing

Demo in Stack Snippets:

$(function() {_x000D_
  $('select').on('change', function(e){_x000D_
<link href="//" rel="stylesheet"/>_x000D_
<link href="//" rel="stylesheet"/>_x000D_
<script src="//"></script>_x000D_
<script src="//"></script>_x000D_
<script src="//"></script>_x000D_
<select class="selectpicker">_x000D_
  <option val="Must"> Mustard </option>_x000D_
  <option val="Cat" > Ketchup </option>_x000D_
  <option val="Rel" > Relish  </option>_x000D_

Solution 2 - Bootstrap Select Custom Events

As this answer alludes, Bootstrap Select has their own set of custom events, including which:

fires after the select's value has been changed. It passes through event, clickedIndex, newValue, oldValue.

And you can use that like this:

      function(e, clickedIndex, newValue, oldValue) {
    console.log(this.value, clickedIndex, newValue, oldValue)

Demo in Stack Snippets:

$(function() {_x000D_
  $("select").on("", _x000D_
        function(e, clickedIndex, newValue, oldValue) {_x000D_
      console.log(this.value, clickedIndex, newValue, oldValue)_x000D_
<link href="//" rel="stylesheet"/>_x000D_
<link href="//" rel="stylesheet"/>_x000D_
<script src="//"></script>_x000D_
<script src="//"></script>_x000D_
<script src="//"></script>_x000D_
<select class="selectpicker">_x000D_
  <option val="Must"> Mustard </option>_x000D_
  <option val="Cat" > Ketchup </option>_x000D_
  <option val="Rel" > Relish  </option>_x000D_

Convert to binary and keep leading zeros in Python

You can use the string formatting mini language:

def binary(num, pre='0b', length=8, spacer=0):
    return '{0}{{:{1}>{2}}}'.format(pre, spacer, length).format(bin(num)[2:])


print binary(1)



EDIT: based on @Martijn Pieters idea

def binary(num, length=8):
    return format(num, '#0{}b'.format(length + 2))

Is it possible to decrypt MD5 hashes?

Technically, it's 'possible', but under very strict conditions (rainbow tables, brute forcing based on the very small possibility that a user's password is in that hash database).

But that doesn't mean it's

  • Viable
  • Secure

You don't want to 'reverse' an MD5 hash. Using the methods outlined below, you'll never need to. 'Reversing' MD5 is actually considered malicious - a few websites offer the ability to 'crack' and bruteforce MD5 hashes - but all they are are massive databases containing dictionary words, previously submitted passwords and other words. There is a very small chance that it will have the MD5 hash you need reversed. And if you've salted the MD5 hash - this won't work either! :)

The way logins with MD5 hashing should work is:

During Registration:
User creates password -> Password is hashed using MD5 -> Hash stored in database

During Login:
User enters username and password -> (Username checked) Password is hashed using MD5 -> Hash is compared with stored hash in database

When 'Lost Password' is needed:

2 options:

  • User sent a random password to log in, then is bugged to change it on first login.


  • User is sent a link to change their password (with extra checking if you have a security question/etc) and then the new password is hashed and replaced with old password in database

How do I truly reset every setting in Visual Studio 2012?

Just repair Visual Studio itself from the control panel and that should do the trick!

Making an image act like a button

You could use an image submit button:

<input type="image"  id="saveform" src="logg.png " alt="Submit Form" />

MySQL DAYOFWEEK() - my week begins with monday

You can easily use the MODE argument:

MySQL :: MySQL 5.5 Reference Manual :: 12.7 Date and Time Functions

If the mode argument is omitted, the value of the default_week_format system variable is used:

MySQL :: MySQL 5.1 Reference Manual :: 5.1.4 Server System Variables

Why do we have to override the equals() method in Java?

To answer your question, firstly I would strongly recommend looking at the Documentation.

Without overriding the equals() method, it will act like "==". When you use the "==" operator on objects, it simply checks to see if those pointers refer to the same object. Not if their members contain the same value.

We override to keep our code clean, and abstract the comparison logic from the If statement, into the object. This is considered good practice and takes advantage of Java's heavily Object Oriented Approach.

C++ How do I convert a std::chrono::time_point to long and back

time_point objects only support arithmetic with other time_point or duration objects.

You'll need to convert your long to a duration of specified units, then your code should work correctly.

jQuery exclude elements with certain class in selector

use this..

$(".content_box a:not('.button')")

Where is the user's Subversion config file stored on the major operating systems?

In TortoiseSVN you can access and modify some settings in the context menu "Settings/General" in explorer.

E.g. the "Global ignore pattern" can be edited directly in the dialog box. Such changings are the stored in the registry as bahrep pointed out in her answer.

(Win10/TortoiseSVN 1.13.1, Build 28686 - 64 Bit)

How to change to an older version of Node.js

Easiest way i found -

  1. Uninstall current version
  2. Download the appropriate .msi installer (x64 or x86) for the desired version from

How to insert a string which contains an "&"

I've found that using either of the following options works:




I don't know enough about databases to know if one is better or "more right" than the other. Also, if there's something better than either of these, please let me know.

How can I replace newlines using PowerShell?

You can use "\\r\\n" also for the new line in powershell. I have used this in servicenow tool.

In my case "\r\n" s not working so i tried "\\r\\n" as "\" this symbol work as escape character in powershell.

Add object to ArrayList at specified index

I think the solution from medopal is what you are looking for.

But just another alternative solution is to use a HashMap and use the key (Integer) to store positions.

This way you won't need to populate it with nulls etc initially, just stick the position and the object in the map as you go along. You can write a couple of lines at the end to convert it to a List if you need it that way.

Table 'performance_schema.session_variables' doesn't exist

Since none of the answers above actually explain what happened, I decided to chime in and bring some more details to this issue.

Yes, the solution is to run the MySQL Upgrade command, as follows: mysql_upgrade -u root -p --force, but what happened?

The root cause for this issue is the corruption of performance_schema, which can be caused by:

  • Organic corruption (volumes going kaboom, engine bug, kernel driver issue etc)
  • Corruption during mysql Patch (it is not unheard to have this happen during a mysql patch, specially for major version upgrades)
  • A simple "drop database performance_schema" will obviously cause this issue, and it will present the same symptoms as if it was corrupted

This issue might have been present on your database even before the patch, but what happened on MySQL 5.7.8 specifically is that the flag show_compatibility_56 changed its default value from being turned ON by default, to OFF. This flag controls how the engine behaves on queries for setting and reading variables (session and global) on various MySQL Versions.

Because MySQL 5.7+ started to read and store these variables on performance_schema instead of on information_schema, this flag was introduced as ON for the first releases to reduce the blast radius of this change and to let users know about the change and get used to it.

OK, but why does the connection fail? Because depending on the driver you are using (and its configuration), it may end up running commands for every new connection initiated to the database (like show variables, for instance). Because one of these commands can try to access a corrupted performance_schema, the whole connection aborts before being fully initiated.

So, in summary, you may (it's impossible to tell now) have had performance_schema either missing or corrupted before patching. The patch to 5.7.8 then forced the engine to read your variables out of performance_schema (instead of information_schema, where it was reading it from because of the flag being turned ON). Since performance_schema was corrupted, the connections are failing.

Running MySQL upgrade is the best approach, despite the downtime. Turning the flag on is one option, but it comes with its own set of implications as it was pointed out on this thread already.

Both should work, but weight the consequences and know your choices :)

How to do a SOAP wsdl web services call from the command line

For Windows I found this working:

Set http = CreateObject("Microsoft.XmlHttp") "GET", "", FALSE
http.send ""
WScript.Echo http.responseText

Reference: CodeProject

Given an array of numbers, return array of products of all other numbers (no division)

My first try, in Python. O(2n):

def product(l):
    product = 1
    num_zeroes = 0
    pos_zero = -1

    # Multiply all and set positions
    for i, x in enumerate(l):
        if x != 0:
            product *= x
            l[i] = 1.0/x
            num_zeroes += 1
            pos_zero = i

    # Warning! Zeroes ahead!
    if num_zeroes > 0:
        l = [0] * len(l)

        if num_zeroes == 1:
            l[pos_zero] = product

        # Now set the definitive elements
        for i in range(len(l)):
            l[i] = int(l[i] * product)

    return l

if __name__ == "__main__":
    print("[0, 0, 4] = " + str(product([0, 0, 4])))
    print("[3, 0, 4] = " + str(product([3, 0, 4])))
    print("[1, 2, 3] = " + str(product([1, 2, 3])))
    print("[2, 3, 4, 5, 6] = " + str(product([2, 3, 4, 5, 6])))
    print("[2, 1, 2, 2, 3] = " + str(product([2, 1, 2, 2, 3])))


[0, 0, 4] = [0, 0, 0]
[3, 0, 4] = [0, 12, 0]
[1, 2, 3] = [6, 3, 2]
[2, 3, 4, 5, 6] = [360, 240, 180, 144, 120]
[2, 1, 2, 2, 3] = [12, 24, 12, 12, 8]

Setting table row height

I found the best answer for my purposes was to use:

.topics tr { 
    overflow: hidden;
    height: 14px;
    white-space: nowrap;

The white-space: nowrap is important as it prevents your row's cells from breaking across multiple lines.

I personally like to add text-overflow: ellipsis to my th and td elements to make the overflowing text look nicer by adding the trailing fullstops, for example Too long gets dots...

Delete rows with blank values in one particular column

An elegant solution with dplyr would be:

df %>%
  # recode empty strings "" by NAs
  na_if("") %>%
  # remove NAs

This table does not contain a unique column. Grid edit, checkbox, Edit, Copy and Delete features are not available

I have been faced with this problem.

The cause is your table doesn't have a primary key field.

And I have a simple solution: Set a field to primary key to specific field that suits your business logic.

For example, I have database thesis_db and field thesis_id, I will press button Primary (key icon) to set thesis_id to become primary key field:

enter image description here

How do I make an input field accept only letters in javaScript?

If you want only letters - so from a to z, lower case or upper case, excluding everything else (numbers, blank spaces, symbols), you can modify your function like this:

function validate() {
    if ( == "") {
        alert("Enter a name");;
        return false;
    if (!/^[a-zA-Z]*$/g.test( {
        alert("Invalid characters");;
        return false;

Does a `+` in a URL scheme/host/path represent a space?

Space characters may only be encoded as "+" in one context: application/x-www-form-urlencoded key-value pairs.

The RFC-1866 (HTML 2.0 specification), paragraph 8.2.1. subparagraph 1. says: "The form field names and values are escaped: space characters are replaced by `+', and then reserved characters are escaped").

Here is an example of such a string in URL where RFC-1866 allows encoding spaces as pluses: "". So, only after "?", spaces can be replaced by pluses (in other cases, spaces should be encoded to %20). This way of encoding form data is also given in later HTML specifications, for example, look for relevant paragraphs about application/x-www-form-urlencoded in HTML 4.01 Specification, and so on.

But, because it's hard to always correctly determine the context, it's the best practice to never encode spaces as "+". It's better to percent-encode all character except "unreserved" defined in RFC-3986, p.2.3. Here is a code example that illustrates what should be encoded. It is given in Delphi (pascal) programming language, but it is very easy to understand how it works for any programmer regardless of the language possessed:

(* percent-encode all unreserved characters as defined in RFC-3986, p.2.3 *)
function UrlEncodeRfcA(const S: AnsiString): AnsiString;
  HexCharArrA: array [0..15] of AnsiChar = '0123456789ABCDEF';
  I: Integer;
  c: AnsiChar;
 // percent-encoding, see RFC-3986, p. 2.1
  Result := S;
  for I := Length(S) downto 1 do
    c := S[I];
    case c of
      'A' .. 'Z', 'a' .. 'z', // alpha
      '0' .. '9',             // digit
      '-', '.', '_', '~':;    // rest of unreserved characters as defined in the RFC-3986, p.2.3
          Result[I] := '%';
          Insert('00', Result, I + 1);
          Result[I + 1] := HexCharArrA[(Byte(C) shr 4) and $F)];
          Result[I + 2] := HexCharArrA[Byte(C) and $F];

function UrlEncodeRfcW(const S: UnicodeString): AnsiString;
  Result := UrlEncodeRfcA(Utf8Encode(S));

Multiple files upload (Array) with CodeIgniter 2.0

    public function imageupload() 

      $count = count($_FILES['userfile']['size']);

  $config['upload_path'] = './uploads/';
  $config['allowed_types'] = 'gif|jpg|png|bmp';
  $config['max_size']   = '0';
  $config['max_width']  = '0';
  $config['max_height']  = '0';

  $config['image_library'] = 'gd2';
  $config['create_thumb'] = TRUE;
  $config['maintain_ratio'] = FALSE;
  $config['width'] = 50;
  $config['height'] = 50;

  foreach($_FILES as $key=>$value)
     for($s=0; $s<=$count-1; $s++)
     $_FILES['userfile']['type']    = $value['type'][$s];
     $_FILES['userfile']['tmp_name'] = $value['tmp_name'][$s]; 
     $_FILES['userfile']['error']       = $value['error'][$s];
     $_FILES['userfile']['size']    = $value['size'][$s];  

         $this->load->library('upload', $config);

         if ($this->upload->do_upload('userfile'))
           $data['userfile'][$i] = $this->upload->data();
       $full_path = $data['userfile']['full_path'];

           $config['source_image'] = $full_path;
           $config['new_image'] = './uploads/resiezedImage';

           $this->load->library('image_lib', $config);

           $data['upload_errors'][$i] = $this->upload->display_errors();

Get class list for element with jQuery

On supporting browsers, you can use DOM elements' classList property.


It is an array-like object listing all of the classes the element has.

If you need to support old browser versions that don't support the classList property, the linked MDN page also includes a shim for it - although even the shim won't work on Internet Explorer versions below IE 8.

104, 'Connection reset by peer' socket error, or When does closing a socket result in a RST rather than FIN?

Don't use wsgiref for production. Use Apache and mod_wsgi, or something else.

We continue to see these connection resets, sometimes frequently, with wsgiref (the backend used by the werkzeug test server, and possibly others like the Django test server). Our solution was to log the error, retry the call in a loop, and give up after ten failures. httplib2 tries twice, but we needed a few more. They seem to come in bunches as well - adding a 1 second sleep might clear the issue.

We've never seen a connection reset when running through Apache and mod_wsgi. I don't know what they do differently, (maybe they just mask them), but they don't appear.

When we asked the local dev community for help, someone confirmed that they see a lot of connection resets with wsgiref that go away on the production server. There's a bug there, but it is going to be hard to find it.

sqlplus statement from command line

I'm able to execute your exact query by just making sure there is a semicolon at the end of my select statement. (Output is actual, connection params removed.)

echo "select 1 from dual;" | sqlplus -s username/password@host:1521/service 



Note that is should matter but this is running on Mac OS X Snow Leopard and Oracle 11g.

Get top first record from duplicate records having no unique identity

You can try the following:

  1. Create a view that simply selects all the columns from the original table but add an extra numeric column that increase in value with each record\row. You may need to make this column a non integer column (e.g a decimal and increment it by 1.00 for each record to use it in the RANK() SQL statement).

  2. Also add another column (e.g. 'RecordRank') to contain calculated ranked values for all columns using the RANK() OVER SQL clause to create values for this column - see references below. The RANK statement allows you to partition the records and then order each partition records according to the values in the order by column (use the Column with increasing values from step 1 for your order by). You use the columns with identical data in the partition clause so all those similar duplicates are partitioned or grouped together, and then ordered by the values in the extra column (order by column from step1).

3, After successfully creating the above view, just write another view to select only records with 'RecordRank' = 1

This should select only one of each record from the duplicates or partitions.

Hope this helps - malcom sankoh

The storage engine for the table doesn't support repair. InnoDB or MyISAM?

InnoDB works slightly different that MyISAM and they both are viable options. You should use what you think it fits the project.

Some keypoints will be:

  1. InnoDB does ACID-compliant transaction.
  2. InnoDB does Referential Integrity (foreign key relations)
  3. MyIsam does full text search, InnoDB doesn't
  4. I have been told InnoDB is faster on executing writes but slower than MyISAM doing reads (I cannot back this up and could not find any article that analyses this, I do however have the guy that told me this in high regard), feel free to ignore this point or do your own research.
  5. Default configuration does not work very well for InnoDB needs to be tweaked accordingly, run a tool like to help you.


  • In my opinion the second point is probably the one were InnoDB has a huge advantage over MyISAM.
  • Full text search not working with InnoDB is a bit of a pain, You can mix different storage engines but be careful when doing so.

Notes2: - I am reading this book "High performance MySQL", the author says "InnoDB loads data and creates indexes slower than MyISAM", this could also be a very important factor when deciding what to use.

In Typescript, what is the ! (exclamation mark / bang) operator when dereferencing a member?

non-null assertion operator

With the non-null assertion operator we can tell the compiler explicitly that an expression has value other than null or undefined. This is can be useful when the compiler cannot infer the type with certainty but we more information than the compiler.


TS code

function simpleExample(nullableArg: number | undefined | null) {
   const normal: number = nullableArg; 
    //   Compile err: 
    //   Type 'number | null | undefined' is not assignable to type 'number'.
    //   Type 'undefined' is not assignable to type 'number'.(2322)

   const operatorApplied: number = nullableArg!; 
    // compiles fine because we tell compiler that null | undefined are excluded 

Compiled JS code

Note that the JS does not know the concept of the Non-null assertion operator since this is a TS feature

"use strict";
function simpleExample(nullableArg) {
    const normal = nullableArg;
    const operatorApplied = nullableArg;

How to convert Observable<any> to array[]

You will need to subscribe to your observables:

    .subscribe(countries => {
        this.myGridOptions.rowData = countries as CountryData[]

And, in your html, wherever needed, you can pass the async pipe to it.

How do you do block comments in YAML?

The spec only describes one way of marking comments:

An explicit comment is marked by a “#” indicator.

That's all. There are no block comments.

Moving up one directory in Python

Obviously that os.chdir('..') is the right answer here. But just FYI, if in the future you come across situation when you have to extensively manipulate directories and paths, here is a great package (Unipath) which lets you treat them as Python objects:

so that you could do something like this:

>>> from unipath import Path
>>> p = Path("/usr/lib/python2.5/")
>>> p.parent
>>> p.ext

Remove first Item of the array (like popping from stack)


$scope.remove = function(item) { 
    $, 1);     

Made changes to .. now it will remove from the top

Failed to import new Gradle project: failed to find Build Tools revision *.0.0

This worked for me after i tryed many solutions:
For some reason the adb process didn't restart itself after installing new packages. Manualy killing adb.exe and attempt to import the project another time solved this problem for me.

Check if file is already open doesn't check if your file is open or not. Instead, it changes the timestamp of the file to the current time.

I used IOException and it works just fine:

  String filePath = "C:\sheet.xlsx";
  FileWriter fw = new FileWriter(filePath );                
catch (IOException e)
    System.out.println("File is open");

Google MAP API Uncaught TypeError: Cannot read property 'offsetWidth' of null

Changing the ID (in all 3 places) from "map-canvas" to "map" fixed it for me, even though I had made sure the IDs were the same, the div had a width and height, and the code wasn't running until after the window load call. It's not the dash; it doesn't seem to work with any other ID than "map".

GCC C++ Linker errors: Undefined reference to 'vtable for XXX', Undefined reference to 'ClassName::ClassName()'

I had this error message. The problem was that I declared a virtual destructor in the header file, but the virtual functions' body was actually not implemented.

Keyboard shortcut to clear cell output in Jupyter notebook

STEP 1 :Click on the "Help"and click on "Edit Keyboard Shortcut" STEP1-screenshot

STEP 2 :Add the Shortcut you desire to the "Clear Cell" field STEP2-screenshot

Google Geocoding API - REQUEST_DENIED

I found that in my case, calling to the service without secure protocol (meaning: http), after adding the key=API_KEY, cause this issue. Changing to https solved it.

C++ Object Instantiation

I've seen this anti-pattern from people who don't quite get the & address-of operator. If they need to call a function with a pointer, they'll always allocate on the heap so they get a pointer.

void FeedTheDog(Dog* hungryDog);

Dog* badDog = new Dog;
delete badDog;

Dog goodDog;

Eclipse: Syntax Error, parameterized types are only if source level is 1.5

My guess would be that while you run eclipse itself with JDK 1.6, it's actually configured with a different default jre.

See Window->preferences->java->Installed JREs and make sure that the checked JRE is 1.6.

If the default JRE is indeed 1.6, chances are that it's a project specific setting. See that the project is configured to use the right JRE.

Where are my postgres *.conf files?

Ubuntu 13.04 installed using software centre :

The location for mine is:


How do I use boolean variables in Perl?

My favourites have always been

use constant FALSE => 1==0;
use constant TRUE => not FALSE;

which is completely independent from the internal representation.

Best practices for Storyboard login screen, handling clearing of data upon logout

I didn't like bhavya's answer because of using AppDelegate inside View Controllers and setting rootViewController has no animation. And Trevor's answer has issue with flashing view controller on iOS8.

UPD 07/18/2015

AppDelegate inside View Controllers:

Changing AppDelegate state (properties) inside view controller breaks encapsulation.

Very simple hierarchy of objects in every iOS project:

AppDelegate (owns window and rootViewController)

ViewController (owns view)

It's ok that objects from the top change objects at the bottom, because they are creating them. But it's not ok if objects on the bottom change objects on top of them (I described some basic programming/OOP principle : DIP (Dependency Inversion Principle : high level module must not depend on the low level module, but they should depend on abstractions)).

If any object will change any object in this hierarchy, sooner or later there will be a mess in the code. It might be ok on the small projects but it's no fun to dig through this mess on the bit projects =]

UPD 07/18/2015

I replicate modal controller animations using UINavigationController (tl;dr: check the project).

I'm using UINavigationController to present all controllers in my app. Initially I displayed login view controller in navigation stack with plain push/pop animation. Than I decided to change it to modal with minimal changes.

How it works:

  1. Initial view controller (or self.window.rootViewController) is UINavigationController with ProgressViewController as a rootViewController. I'm showing ProgressViewController because DataModel can take some time to initialize because it inits core data stack like in this article (I really like this approach).

  2. AppDelegate is responsible for getting login status updates.

  3. DataModel handles user login/logout and AppDelegate is observing it's userLoggedIn property via KVO. Arguably not the best method to do this but it works for me. (Why KVO is bad, you can check in this or this article (Why Not Use Notifications? part).

  4. ModalDismissAnimator and ModalPresentAnimator are used to customize default push animation.

How animators logic works:

  1. AppDelegate sets itself as a delegate of self.window.rootViewController (which is UINavigationController).

  2. AppDelegate returns one of animators in -[AppDelegate navigationController:animationControllerForOperation:fromViewController:toViewController:] if necessary.

  3. Animators implement -transitionDuration: and -animateTransition: methods. -[ModalPresentAnimator animateTransition:]:

    - (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
        UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
        [[transitionContext containerView] addSubview:toViewController.view];
        CGRect frame = toViewController.view.frame;
        CGRect toFrame = frame;
        frame.origin.y = CGRectGetHeight(frame);
        toViewController.view.frame = frame;
        [UIView animateWithDuration:[self transitionDuration:transitionContext]
             toViewController.view.frame = toFrame;
         } completion:^(BOOL finished)
             [transitionContext completeTransition:![transitionContext transitionWasCancelled]];

Test project is here.

Easy way to test an LDAP User's Credentials

You should check out Softerra's LDAP Browser (the free version of LDAP Administrator), which can be downloaded here :

I've used this application extensively for all my Active Directory, OpenLDAP, and Novell eDirectory development, and it has been absolutely invaluable.

If you just want to check and see if a username\password combination works, all you need to do is create a "Profile" for the LDAP server, and then enter the credentials during Step 3 of the creation process :

enter image description here

By clicking "Finish", you'll effectively issue a bind to the server using the credentials, auth mechanism, and password you've specified. You'll be prompted if the bind does not work.

Convert LocalDate to LocalDateTime or java.sql.Timestamp

function call asStartOfDay() on java.time.LocalDate object returns a java.time.LocalDateTime object

JavaScript: Difference between .forEach() and .map()

The difference lies in what they return. After execution:

returns an array of elements resulting from the processed function; while:


returns undefined.

How to convert index of a pandas dataframe into a column?

To provide a bit more clarity, let's look at a DataFrame with two levels in its index (a MultiIndex).

index = pd.MultiIndex.from_product([['TX', 'FL', 'CA'], 
                                    ['North', 'South']], 
                                   names=['State', 'Direction'])

df = pd.DataFrame(index=index, 
                  data=np.random.randint(0, 10, (6,4)), 

enter image description here

The reset_index method, called with the default parameters, converts all index levels to columns and uses a simple RangeIndex as new index.


enter image description here

Use the level parameter to control which index levels are converted into columns. If possible, use the level name, which is more explicit. If there are no level names, you can refer to each level by its integer location, which begin at 0 from the outside. You can use a scalar value here or a list of all the indexes you would like to reset.

df.reset_index(level='State') # same as df.reset_index(level=0)

enter image description here

In the rare event that you want to preserve the index and turn the index into a column, you can do the following:

# for a single level

# for all levels

What are Unwind segues for and how do you use them?

Something that I didn't see mentioned in the other answers here is how you deal with unwinding when you don't know where the initial segue originated, which to me is an even more important use case. For example, say you have a help view controller (H) that you display modally from two different view controllers (A and B):

A ? H
B ? H

How do you set up the unwind segue so that you go back to the correct view controller? The answer is that you declare an unwind action in A and B with the same name, e.g.:

// put in AViewController.swift and BViewController.swift
@IBAction func unwindFromHelp(sender: UIStoryboardSegue) {
    // empty

This way, the unwind will find whichever view controller (A or B) initiated the segue and go back to it.

In other words, think of the unwind action as describing where the segue is coming from, rather than where it is going to.

macro for Hide rows in excel 2010

Well, you're on the right path, Benno!

There are some tips regarding VBA programming that might help you out.

  1. Use always explicit references to the sheet you want to interact with. Otherwise, Excel may 'assume' your code applies to the active sheet and eventually you'll see it screws your spreadsheet up.

  2. As lionz mentioned, get in touch with the native methods Excel offers. You might use them on most of your tricks.

  3. Explicitly declare your variables... they'll show the list of methods each object offers in VBA. It might save your time digging on the internet.

Now, let's have a draft code...

Remember this code must be within the Excel Sheet object, as explained by lionz. It only applies to Sheet 2, is up to you to adapt it to both Sheet 2 and Sheet 3 in the way you prefer.

Hope it helps!

Private Sub Worksheet_Change(ByVal Target As Range)

    Dim oSheet As Excel.Worksheet

    'We only want to do something if the changed cell is B6, right?
    If Target.Address = "$B$6" Then

        'Checks if it's a number...
        If IsNumeric(Target.Value) Then

            'Let's avoid values out of your bonds, correct?
            If Target.Value > 0 And Target.Value < 51 Then

                'Let's assign the worksheet we'll show / hide rows to one variable and then
                '   use only the reference to the variable itself instead of the sheet name.
                '   It's safer.

                'You can alternatively replace 'sheet 2' by 2 (without quotes) which will represent
                '   the sheet index within the workbook
                Set oSheet = ActiveWorkbook.Sheets("Sheet 2")

                'We'll unhide before hide, to ensure we hide the correct ones
                oSheet.Range("A7:A56").EntireRow.Hidden = False

                oSheet.Range("A" & Target.Value + 7 & ":A56").EntireRow.Hidden = True

            End If

        End If

    End If

End Sub

How do I convert seconds to hours, minutes and seconds?

dateutil.relativedelta is convenient if you need to access hours, minutes and seconds as floats as well. datetime.timedelta does not provide a similar interface.

from dateutil.relativedelta import relativedelta
rt = relativedelta(seconds=5440)
    int(rt.hours), int(rt.minutes), int(rt.seconds)))



how to convert current date to YYYY-MM-DD format with angular 2

Add the template and give date pipe, you need to use escape characters for the format of the date. You can give any format as you want like 'MM-yyyy-dd' etc.

template: '{{ current_date | date: \'yyyy-MM-dd\' }}',

Set variable in jinja

Just Set it up like this

{% set active_link = recordtype -%}

Display PDF within web browser

The browser's plugin controls those settings, so you can't force it. However, you can do a simple <a href="whatver.pdf"> instead of <a href="whatever.pdf" target="_blank">.

How to crop an image using PIL?

You need to import PIL (Pillow) for this. Suppose you have an image of size 1200, 1600. We will crop image from 400, 400 to 800, 800

from PIL import Image
img ="ImageName.jpg")
area = (400, 400, 800, 800)
cropped_img = img.crop(area)

Regular expression "^[a-zA-Z]" or "[^a-zA-Z]"

There is a difference.

When the ^ character appears outside of [] matches the beginning of the line (or string). When the ^ character appears inside the [], it matches any character not appearing inside the [].

Maximum packet size for a TCP connection

The absolute limitation on TCP packet size is 64K (65535 bytes), but in practicality this is far larger than the size of any packet you will see, because the lower layers (e.g. ethernet) have lower packet sizes.

The MTU (Maximum Transmission Unit) for Ethernet, for instance, is 1500 bytes. Some types of networks (like Token Ring) have larger MTUs, and some types have smaller MTUs, but the values are fixed for each physical technology.

Should I use string.isEmpty() or "".equals(string)?

It doesn't really matter. "".equals(str) is more clear in my opinion.

isEmpty() returns count == 0;

EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0) on dispatch_semaphore_dispose

My problem was took IBOutlet but didn't connect with interface builder and using in swift file.

How do you create an asynchronous method in C#?

I don't recommend StartNew unless you need that level of complexity.

If your async method is dependent on other async methods, the easiest approach is to use the async keyword:

private static async Task<DateTime> CountToAsync(int num = 10)
  for (int i = 0; i < num; i++)
    await Task.Delay(TimeSpan.FromSeconds(1));

  return DateTime.Now;

If your async method is doing CPU work, you should use Task.Run:

private static async Task<DateTime> CountToAsync(int num = 10)
  await Task.Run(() => ...);
  return DateTime.Now;

You may find my async/await intro helpful.

How to "perfectly" override a dict?

All you will have to do is

class BatchCollection(dict):
    def __init__(self, *args, **kwargs):
        dict.__init__(*args, **kwargs)


class BatchCollection(dict):
    def __init__(self, inpt={}):
        super(BatchCollection, self).__init__(inpt)

A sample usage for my personal use

class BatchCollection(dict):
    def __init__(self, inpt={}):
        dict.__init__(*args, **kwargs)

    def __setitem__(self, key, item):
        if (isinstance(key, tuple) and len(key) == 2
                and isinstance(item, collections.Iterable)):
            # self.__dict__[key] = item
            super(BatchCollection, self).__setitem__(key, item)
            raise Exception(
                "Valid key should be a tuple (database_name, table_name) "
                "and value should be iterable")

Note: tested only in python3

How to delete all files and folders in a folder by cmd call

Yes! Use Powershell:

powershell -Command "Remove-Item 'c:\destination\*' -Recurse -Force"

How to store directory files listing into an array?

Try with:

#! /bin/bash

while read line
    array[ $i ]="$line"        
    (( i++ ))
done < <(ls -ls)

echo ${array[1]}

In your version, the while runs in a subshell, the environment variables you modify in the loop are not visible outside it.

(Do keep in mind that parsing the output of ls is generally not a good idea at all.)

Difference of two date time in sql server

For Me This worked Perfectly Convert(varchar(8),DATEADD(SECOND,DATEDIFF(SECOND,LogInTime,LogOutTime),0),114)

and the Output is HH:MM:SS which is shown accurately in my case.

How do I programmatically click on an element in JavaScript? is a standard method outlined by the W3C DOM specification. Mozilla's Gecko/Firefox follows the standard and only allows this method to be called on INPUT elements.

how to dynamically add options to an existing select in vanilla javascript

I guess something like this would do the job.

var option = document.createElement("option");
option.text = "Text";
option.value = "myvalue";
var select = document.getElementById("daySelect");

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

In my case, I am using a tiny .exe that reloads the referenced DLLs via Reflection. So I just do these steps which saves my day:

From project properties on solution explorer, at build tab, I choose target platfrom x86

Continue For loop

You're thinking of a continue statement like Java's or Python's, but VBA has no such native statement, and you can't use VBA's Next like that.

You could achieve something like what you're trying to do using a GoTo statement instead, but really, GoTo should be reserved for cases where the alternatives are contrived and impractical.

In your case with a single "continue" condition, there's a really simple, clean, and readable alternative:

    If Not InStr(sname, "Configuration item") Then
        '// other code to copy paste and do various stuff
    End If

Keyboard shortcut to comment lines in Sublime Text 2

On a Mac with a US keyboard, you want cmd+/.

Alternative to iFrames with HTML5

No, there isn't an equivalent. The <iframe> element is still valid in HTML5. Depending on what exact interaction you need there might be different APIs. For example there's the postMessage method which allows you to achieve cross domain javascript interaction. But if you want to display cross domain HTML contents (styled with CSS and made interactive with javascript) iframe stays as a good way to do.

How can I create a war file of my project in NetBeans?

If NetBeans haven't created your dist folder, execute the do-dist ant target:

In commandline navigate to the directory of your project, the one containing a build.xml file
> ant do-dist

If ant runs fine (most likely), your dist folder will be created, containing the .war file.

Convert NSNumber to int in Objective-C

Have a look at the documentation. Use the intValue method:

NSNumber *number = [dict objectForKey:@"integer"];
int intValue = [number intValue];

Get width height of remote image from url

Get image size with jQuery

function getMeta(url){
        load : function(){
            alert(this.width+' '+this.height);
        src  : url

Get image size with JavaScript

function getMeta(url){   
    var img = new Image();
    img.onload = function(){
        alert( this.width+' '+ this.height );
    img.src = url;

Get image size with JavaScript (modern browsers, IE9+ )

function getMeta(url){   
    var img = new Image();
    img.addEventListener("load", function(){
        alert( this.naturalWidth +' '+ this.naturalHeight );
    img.src = url;

Use the above simply as: getMeta( "" );

fatal error LNK1104: cannot open file 'libboost_system-vc110-mt-gd-1_51.lib'

In case you have trouble building boost or prefer not to do that, an alternative is to download the lib files from SourceForge. The link will take you to a folder of zipped lib and dll files for version 1.51. But, you should be able to edit the link to specify the version of choice. Apparently the installer from BoostPro has some issues.

How to Read from a Text File, Character by Character in C++

Assuming that temp is a char and textFile is a std::fstream derivative...

The syntax you're looking for is

textFile.get( temp );

endsWith in JavaScript


will work on all browsers, doesn't require monkey patching String, and doesn't require scanning the entire string as lastIndexOf does when there is no match.

If you want to match a constant string that might contain regular expression special characters, such as '$', then you can use the following:

function makeSuffixRegExp(suffix, caseInsensitive) {
  return new RegExp(
      String(suffix).replace(/[$%()*+.?\[\\\]{|}]/g, "\\$&") + "$",
      caseInsensitive ? "i" : "");

and then you can use it like this


Property 'map' does not exist on type 'Observable<Response>'

for all those linux users that are having this problem, check if the rxjs-compat folder is locked. I had this exact same issue and I went in terminal, used the sudo su to give permission to the whole rxjs-compat folder and it was fixed. Thats assuming you imported

import 'rxjs/add/operator/map';
import 'rxjs/add/operator/catch'; 

in the project.ts file where the original .map error occurred.

Printing Lists as Tabular Data

When I do this, I like to have some control over the details of how the table is formatted. In particular, I want header cells to have a different format than body cells, and the table column widths to only be as wide as each one needs to be. Here's my solution:

def format_matrix(header, matrix,
                  top_format, left_format, cell_format, row_delim, col_delim):
    table = [[''] + header] + [[name] + row for name, row in zip(header, matrix)]
    table_format = [['{:^{}}'] + len(header) * [top_format]] \
                 + len(matrix) * [[left_format] + len(header) * [cell_format]]
    col_widths = [max(
                      len(format.format(cell, 0))
                      for format, cell in zip(col_format, col))
                  for col_format, col in zip(zip(*table_format), zip(*table))]
    return row_delim.join(
                   format.format(cell, width)
                   for format, cell, width in zip(row_format, row, col_widths))
               for row_format, row in zip(table_format, table))

print format_matrix(['Man Utd', 'Man City', 'T Hotspur', 'Really Long Column'],
                    [[1, 2, 1, -1], [0, 1, 0, 5], [2, 4, 2, 2], [0, 1, 0, 6]],
                    '{:^{}}', '{:<{}}', '{:>{}.3f}', '\n', ' | ')

Here's the output:

                   | Man Utd | Man City | T Hotspur | Really Long Column
Man Utd            |   1.000 |    2.000 |     1.000 |             -1.000
Man City           |   0.000 |    1.000 |     0.000 |              5.000
T Hotspur          |   2.000 |    4.000 |     2.000 |              2.000
Really Long Column |   0.000 |    1.000 |     0.000 |              6.000

Powershell: Get FQDN Hostname

(Get-ADComputer $(hostname)).DNSHostName

Definitive way to trigger keypress events with jQuery

Ok, for me that work with this...

var e2key = function(e) {
    if (!e) return '';
    var event2key = {
        '96':'0', '97':'1', '98':'2', '99':'3', '100':'4', '101':'5', '102':'6', '103':'7', '104':'8', '105':'9', // Chiffres clavier num
        '48':'m0', '49':'m1', '50':'m2', '51':'m3', '52':'m4', '53':'m5', '54':'m6', '55':'m7', '56':'m8', '57':'m9', // Chiffres caracteres speciaux
        '65':'a', '66':'b', '67':'c', '68':'d', '69':'e', '70':'f', '71':'g', '72':'h', '73':'i', '74':'j', '75':'k', '76':'l', '77':'m', '78':'n', '79':'o', '80':'p', '81':'q', '82':'r', '83':'s', '84':'t', '85':'u', '86':'v', '87':'w', '88':'x', '89':'y', '90':'z', // Alphabet
        '37':'left', '39':'right', '38':'up', '40':'down', '13':'enter', '27':'esc', '32':'space', '107':'+', '109':'-', '33':'pageUp', '34':'pageDown' // KEYCODES
    return event2key[(e.which || e.keyCode)];

var page5Key = function(e, customKey) {
    if (e) e.preventDefault();
    switch(e2key(customKey || e)) {
        case 'left': /*...*/ break;
        case 'right': /*...*/ break;

$(document).bind('keyup', page5Key);

$(document).trigger('keyup', [{preventDefault:function(){},keyCode:37}]); 

Dealing with timestamps in R

You want the (standard) POSIXt type from base R that can be had in 'compact form' as a POSIXct (which is essentially a double representing fractional seconds since the epoch) or as long form in POSIXlt (which contains sub-elements). The cool thing is that arithmetic etc are defined on this -- see help(DateTimeClasses)

Quick example:

R> now <- Sys.time()
R> now
[1] "2009-12-25 18:39:11 CST"
R> as.numeric(now)
[1] 1.262e+09
R> now + 10  # adds 10 seconds
[1] "2009-12-25 18:39:21 CST"
R> as.POSIXlt(now)
[1] "2009-12-25 18:39:11 CST"
R> str(as.POSIXlt(now))
 POSIXlt[1:9], format: "2009-12-25 18:39:11"
R> unclass(as.POSIXlt(now))
[1] 11.79

[1] 39

[1] 18

[1] 25

[1] 11

[1] 109

[1] 5

[1] 358

[1] 0

[1] "America/Chicago" "CST"             "CDT"            

As for reading them in, see help(strptime)

As for difference, easy too:

R> Jan1 <- strptime("2009-01-01 00:00:00", "%Y-%m-%d %H:%M:%S")
R> difftime(now, Jan1, unit="week")
Time difference of 51.25 weeks

Lastly, the zoo package is an extremely versatile and well-documented container for matrix with associated date/time indices.

Transition of background-color

As far as I know, transitions currently work in Safari, Chrome, Firefox, Opera and Internet Explorer 10+.

This should produce a fade effect for you in these browsers:

a {_x000D_
    background-color: #FF0;_x000D_
a:hover {_x000D_
    background-color: #AD310B;_x000D_
    -webkit-transition: background-color 1000ms linear;_x000D_
    -ms-transition: background-color 1000ms linear;_x000D_
    transition: background-color 1000ms linear;_x000D_
<a>Navigation Link</a>

Note: As pointed out by Gerald in the comments, if you put the transition on the a, instead of on a:hover it will fade back to the original color when your mouse moves away from the link.

This might come in handy, too: CSS Fundamentals: CSS 3 Transitions

Using std::max_element on a vector<double>

min/max_element return the iterator to the min/max element, not the value of the min/max element. You have to dereference the iterator in order to get the value out and assign it to a double. That is:

cLower = *min_element(C.begin(), C.end());

How to detect incoming calls, in an Android device?

this may helps you and also add require permision

public class PhoneListener extends PhoneStateListener
    private Context context;
    public static String getincomno;

    public PhoneListener(Context c) {
        Log.i("CallRecorder", "PhoneListener constructor");
        context = c;

    public void onCallStateChanged (int state, String incomingNumber)

        // here for Outgoing number make null to get incoming number
        CallBroadcastReceiver.numberToCall = null;
        getincomno = incomingNumber;

        switch (state) {
        case TelephonyManager.CALL_STATE_IDLE:

        case TelephonyManager.CALL_STATE_RINGING:
            Log.d("CallRecorder", "CALL_STATE_RINGING");
        case TelephonyManager.CALL_STATE_OFFHOOK:


curl error 18 - transfer closed with outstanding read data remaining

I bet this is related to a wrong Content-Length header sent by the peer. My advice is to let curl set the length by itself.

Targeting only Firefox with CSS

A variation on your idea is to have a server-side USER-AGENT detector that will figure out what style sheet to attach to the page. This way you can have a firefox.css, ie.css, opera.css, etc.

You can accomplish a similar thing in Javascript itself, although you may not regard it as clean.

I have done a similar thing by having a default.css which includes all common styles and then specific style sheets are added to override, or enhance the defaults.

How to append to New Line in Node.js

use \r\n combination to append a new line in node js

  var stream = fs.createWriteStream("udp-stream.log", {'flags': 'a'});
  stream.once('open', function(fd) {

TypeScript enum to object array

If you are using ES8

For this case only it will work perfectly fine. It will give you value array of the given enum.

enum Colors {
  WHITE = 0,
  BLACK = 1,
  BLUE = 3

const colorValueArray = Object.values(Colors); //[ 'WHITE', 'BLACK', 'BLUE', 0, 1, 3 ]

You will get colorValueArray like this [ 'WHITE', 'BLACK', 'BLUE', 0, 1, 3 ]. All the keys will be in first half of the array and all the values in second half.

Even this kind of enum will work fine

enum Operation {

But this solution will not work for Heterogeneous enums like this

enum BooleanLikeHeterogeneousEnum {
  No = 0,
  Yes = "YES",

Temporarily disable all foreign key constraints

There is a easy way to this.

-- Disable all the constraint in database

-- Enable all the constraint in database

Reference SQL SERVER – Disable All the Foreign Key Constraint in Database – Enable All the Foreign Key Constraint in Database

"git rebase origin" vs."git rebase origin/master"

You can make a new file under [.git\refs\remotes\origin] with name "HEAD" and put content "ref: refs/remotes/origin/master" to it. This should solve your problem.

It seems that clone from an empty repos will lead to this. Maybe the empty repos do not have HEAD because no commit object exist.

You can use the

git log --remotes --branches --oneline --decorate

to see the difference between each repository, while the "problem" one do not have "origin/HEAD"

Edit: Give a way using command line
You can also use git command line to do this, they have the same result

git symbolic-ref refs/remotes/origin/HEAD refs/remotes/origin/master

How to make Java Set?

Like this:

import java.util.*;
Set<Integer> a = new HashSet<Integer>();
a.add( 1);
a.add( 2);
a.add( 3);

Or adding from an Array/ or multiple literals; wrap to a list, first.

Integer[] array = new Integer[]{ 1, 4, 5};
Set<Integer> b = new HashSet<Integer>();
b.addAll( Arrays.asList( b));         // from an array variable
b.addAll( Arrays.asList( 8, 9, 10));  // from literals

To get the intersection:

// copies all from A;  then removes those not in B.
Set<Integer> r = new HashSet( a);
r.retainAll( b);
// and print;   r.toString() implied.
System.out.println("A intersect B="+r);

Hope this answer helps. Vote for it!

$http.get(...).success is not a function

This might be redundant but the above most voted answer says .then(function (success) and that didn't work for me as of Angular version 1.5.8. Instead use response then inside the block got me my json data I was looking for.

    method: 'get', 
    url: 'data/data.json'
}).then(function (response) {
    console.log(response, 'res');
    data =;
},function (error){
    console.log(error, 'can not get data.');

How to properly express JPQL "join fetch" with "where" clause as JPA 2 CriteriaQuery?

In JPQL the same is actually true in the spec. The JPA spec does not allow an alias to be given to a fetch join. The issue is that you can easily shoot yourself in the foot with this by restricting the context of the join fetch. It is safer to join twice.

This is normally more an issue with ToMany than ToOnes. For example,

Select e from Employee e 
join fetch e.phones p 
where p.areaCode = '613'

This will incorrectly return all Employees that contain numbers in the '613' area code but will left out phone numbers of other areas in the returned list. This means that an employee that had a phone in the 613 and 416 area codes will loose the 416 phone number, so the object will be corrupted.

Granted, if you know what you are doing, the extra join is not desirable, some JPA providers may allow aliasing the join fetch, and may allow casting the Criteria Fetch to a Join.

Reading string by char till end of line C/C++

If you are using C function fgetc then you should check a next character whether it is equal to the new line character or to EOF. For example

unsigned int count = 0;
while ( 1 )
   int c = fgetc( FileStream );

   if ( c == EOF || c == '\n' )
      printF( "The length of the line is %u\n", count );
      count = 0;
      if ( c == EOF ) break;

or maybe it would be better to rewrite the code using do-while loop. For example

unsigned int count = 0;
   int c = fgetc( FileStream );

   if ( c == EOF || c == '\n' )
      printF( "The length of the line is %u\n", count );
      count = 0;
} while ( c != EOF );

Of course you need to insert your own processing of read xgaracters. It is only an example how you could use function fgetc to read lines of a file.

But if the program is written in C++ then it would be much better if you would use std::ifstream and std::string classes and function std::getline to read a whole line.

Why powershell does not run Angular commands?

I solved my problem by running below command

Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser

Difference between thread's context class loader and normal classloader

Each class will use its own classloader to load other classes. So if ClassA.class references ClassB.class then ClassB needs to be on the classpath of the classloader of ClassA, or its parents.

The thread context classloader is the current classloader for the current thread. An object can be created from a class in ClassLoaderC and then passed to a thread owned by ClassLoaderD. In this case the object needs to use Thread.currentThread().getContextClassLoader() directly if it wants to load resources that are not available on its own classloader.

Working copy locked error in tortoise svn while committing

I managed to lock myself out of a file in svn - don't know how - but when I tried (re)-getting the lock (Tortoise was showing the "Get Lock" option for the file), it complained that already had the lock. I tried deleting the file and committing the directory change - same result. I tried CleanUp (including refreshing the overlay), but that failed too.

The solution was to go into the Tortoise repo-browser, find the file and use the break lock function.

Entity Framework (EF) Code First Cascade Delete for One-to-Zero-or-One relationship

You could also disable the cascade delete convention in global scope of your application by doing this:


Could not load file or assembly 'Microsoft.ReportViewer.WebForms'

Updating ReportViewer should works. Use below instruction to install updated ReportViewer from Nuget Package Manager console.

Install-Package Microsoft.ReportingServices.ReportViewerControl.WebForms

Just add below assembly reference in your aspx file.

Here, is the version number of the ReportViewerControl.WebForms that was installed in my VS. Please check Reference of the Solution to confirm the version number. No need to add PublicTokens (if multiple installation exists, it may creates trouble again).

Node.js global proxy setting

While not a Nodejs setting, I suggest you use proxychains which I find rather convenient. It is probably available in your package manager.

After setting the proxy in the config file (/etc/proxychains.conf for me), you can run proxychains npm start or proxychains4 npm start (i.e. proxychains [command_to_proxy_transparently]) and all your requests will be proxied automatically.

Config settings for me:

These are the minimal settings you will have to append

## Exclude all localhost connections (dbs and stuff)
## Set the proxy type, ip and port here
http 8080

(You can get the ip of the proxy by using nslookup [proxyurl])

Maximum value for long integer

Direct answer to title question:

Integers are unlimited in size and have no maximum value in Python.

Answer which addresses stated underlying use case:

According to your comment of what you're trying to do, you are currently thinking something along the lines of

minval = MAXINT;
for (i = 1; i < num_elems; i++)
    if a[i] < a[i-1]
        minval = a[i];

That's not how to think in Python. A better translation to Python (but still not the best) would be

minval = a[0]  # Just use the first value
for i in range(1, len(a)):
    minval = min(a[i], a[i - 1])

Note that the above doesn't use MAXINT at all. That part of the solution applies to any programming language: You don't need to know the highest possible value just to find the smallest value in a collection.

But anyway, what you really do in Python is just

minval = min(a)

That is, you don't write a loop at all. The built-in min() function gets the minimum of the whole collection.

How to delete Certain Characters in a excel 2010 cell

Replace [ with nothing, then ] with nothing.

Detect enter press in JTextField

Add an event for KeyPressed.

private void jTextField1KeyPressed(java.awt.event.KeyEvent evt) {
  if(evt.getKeyCode() == KeyEvent.VK_ENTER) {
      // Enter was pressed. Your code goes here.

Is there a way to do repetitive tasks at intervals?

A broader answer to this question might consider the Lego brick approach often used in Occam, and offered to the Java community via JCSP. There is a very good presentation by Peter Welch on this idea.

This plug-and-play approach translates directly to Go, because Go uses the same Communicating Sequential Process fundamentals as does Occam.

So, when it comes to designing repetitive tasks, you can build your system as a dataflow network of simple components (as goroutines) that exchange events (i.e. messages or signals) via channels.

This approach is compositional: each group of small components can itself behave as a larger component, ad infinitum. This can be very powerful because complex concurrent systems are made from easy to understand bricks.

Footnote: in Welch's presentation, he uses the Occam syntax for channels, which is ! and ? and these directly correspond to ch<- and <-ch in Go.

LF will be replaced by CRLF in git - What is that and is it important?

If you want, you can deactivate this feature in your git core config using

git config core.autocrlf false

But it would be better to just get rid of the warnings using

git config core.autocrlf true

Socket.IO - how do I get a list of connected sockets/clients? 1.4.4

Sample code for you.

function get_clients_by_room(roomId, namespace) {
        io.of(namespace || "/").in(roomId).clients(function (error, clients) {
            if (error) { throw error; }
            console.log(clients[0]); // => [Anw2LatarvGVVXEIAAAD]
            console.log(io.sockets.sockets[clients[0]]); //socket detail
            return clients;

I think will help someone this code block.

How to make a Qt Widget grow with the window size?

The accepted answer (its image) is wrong, at least now in QT5. Instead you should assign a layout to the root object/widget (pointing to the aforementioned image, it should be the MainWindow instead of centralWidget). Also note that you must have at least one QObject created beneath it for this to work. Do this and your ui will become responsive to window resizing.

How to make Python speak

This is what you are looking for. A complete TTS solution for the Mac. You can use this standalone or as a co-location Mac server for web apps:

How to format LocalDate to string?

Could be short as:"dd/MM/yyyy"));

Abort Ajax requests using jQuery

You can't recall the request but you can set a timeout value after which the response will be ignored. See this page for jquery AJAX options. I believe that your error callback will be called if the timeout period is exceeded. There is already a default timeout on every AJAX request.

You can also use the abort() method on the request object but, while it will cause the client to stop listening for the event, it may probably will not stop the server from processing it.

Reading CSV files using C#

First of all need to understand what is CSV and how to write it.

  1. Every next string ( /r/n ) is next "table" row.
  2. "Table" cells is separated by some delimiter symbol. Most often used symbols is \t or ,
  3. Every cell possibly can contain this delimiter symbol (cell must to start with quotes symbol and ends with this symbol in this case)
  4. Every cell possibly can contains /r/n sybols (cell must to start with quotes symbol and ends with this symbol in this case)

The easiest way for C#/Visual Basic to work with CSV files is to use standard Microsoft.VisualBasic library. You just need to add needed reference, and the following string to your class:

using Microsoft.VisualBasic.FileIO;

Yes, you can use it in C#, don't worry. This library can read relatively big files and supports all of needed rules, so you will be able to work with all of CSV files.

Some time ago I had wrote simple class for CSV read/write based on this library. Using this simple class you will be able to work with CSV like with 2 dimensions array. You can find my class by the following link:

Simple example of using:

Csv csv = new Csv("\t");//delimiter symbol


var row1Cell6Value = csv.Rows[0][5];



“Unable to find manifest signing certificate in the certificate store” - even when add new key

You said you copied files from another computer. After you copied them, did you 'Unblock' them? Specifically the .snk file should be checked to make sure it is not marked as unsafe.

json_encode is returning NULL?

For me, an issue where json_encode would return null encoding of an entity was because my jsonSerialize implementation fetched entire objects for related entities; I solved the issue by making sure that I fetched the ID of the related/associated entity and called ->toArray() when there were more than one entity associated with the object to be json serialized. Note, I'm speaking about cases where one implements JsonSerializable on entities.

Execute function after Ajax call is complete

You should set async = false in head. Use post/get instead of ajax.

jQuery.ajaxSetup({ async: false });

        url: 'api.php',
        data: 'id1=' + q + '',
        dataType: 'json',
        success: function (data) {

            id = data[0];
            vname = data[1];


How can I determine browser window size on server side C#

Here's an Ajax, asxh handler and session variables approach:


using System;
using System.Web;

public class windowSize : IHttpHandler , System.Web.SessionState.IRequiresSessionState  {

    public void ProcessRequest (HttpContext context) {
        context.Response.ContentType = "application/json";

        var json = new System.Web.Script.Serialization.JavaScriptSerializer();
        var output = json.Serialize(new { isFirst = context.Session["BrowserWidth"] == null });

        context.Session["BrowserWidth"] =  context.Request.QueryString["Width"]; 
        context.Session["BrowserHeight"] = context.Request.QueryString["Height"];

    public bool IsReusable
        get { throw new NotImplementedException(); }


window.onresize = function (event) {
function SetWidthHeight() {
    var height = $(window).height();
    var width = $(window).width();
        url: "windowSize.ashx",
        data: {
            'Height': height,
            'Width': width
        contentType: "application/json; charset=utf-8",
        dataType: "json"
    }).done(function (data) {     
        if (data.isFirst) {
    }).fail(function (xhr) {
        alert("Problem to retrieve browser size.");

$(function () {

On aspx file:

<script src="Scripts/jquery-1.9.1.min.js"></script>
<script src="Scripts/BrowserWindowSize.js"></script>
<asp:Label ID="lblDim" runat="server" Text=""></asp:Label>

Code behind:

protected void Page_Load(object sender, EventArgs e)
      if (Session["BrowserWidth"] != null)
          // Do all code here to avoid double execution first time
          // ....
          lblDim.Text = "Width: " + Session["BrowserWidth"] + " Height: " + Session["BrowserHeight"];