Programs & Examples On #Jquery ui draggable

The jQuery UI Draggable plugin makes selected elements draggable with mouse movement.

Draw a connecting line between two elements

D3 has hundreds of examples, some of which are suitable for this question.

Examples without drag and drop, that are fixed:

Examples without drag and drop, that are interactive:

Examples with dragging and dropping:

This answer is based off of Glenn Dayton's answer.

Script Tag - async & defer

This image explains normal script tag, async and defer

enter image description here

  • Async scripts are executed as soon as the script is loaded, so it doesn't guarantee the order of execution (a script you included at the end may execute before the first script file )

  • Defer scripts guarantees the order of execution in which they appear in the page.

Ref this link : http://www.growingwiththeweb.com/2014/02/async-vs-defer-attributes.html

Cannot deserialize instance of object out of START_ARRAY token in Spring Webservice

Your json contains an array, but you're trying to parse it as an object. This error occurs because objects must start with {.

You have 2 options:

  1. You can get rid of the ShopContainer class and use Shop[] instead

    ShopContainer response  = restTemplate.getForObject(
        url, ShopContainer.class);
    

    replace with

    Shop[] response  = restTemplate.getForObject(url, Shop[].class);
    

    and then make your desired object from it.

  2. You can change your server to return an object instead of a list

    return mapper.writerWithDefaultPrettyPrinter().writeValueAsString(list);
    

    replace with

    return mapper.writerWithDefaultPrettyPrinter().writeValueAsString(
        new ShopContainer(list));
    

Calling startActivity() from outside of an Activity context

At the Android 28(Android P) startActivity

if ((intent.getFlags() & Intent.FLAG_ACTIVITY_NEW_TASK) == 0
        && (targetSdkVersion < Build.VERSION_CODES.N
                || targetSdkVersion >= Build.VERSION_CODES.P)
        && (options == null
                || ActivityOptions.fromBundle(options).getLaunchTaskId() == -1)) {
    throw new AndroidRuntimeException(
            "Calling startActivity() from outside of an Activity "
                    + " context requires the FLAG_ACTIVITY_NEW_TASK flag."
                    + " Is this really what you want?");
}

So the best way is add FLAG_ACTIVITY_NEW_TASK

Intent intent = new Intent(context, XXXActivity.class);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
    intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
}
context.startActivity(intent);

Integrating CSS star rating into an HTML form

How about this? I needed the exact same thing, I had to create one from scratch. It's PURE CSS, and works in IE9+ Feel-free to improve upon it.

Demo: http://www.d-k-j.com/Articles/Web_Development/Pure_CSS_5_Star_Rating_System_with_Radios/

<ul class="form">
    <li class="rating">
        <input type="radio" name="rating" value="0" checked /><span class="hide"></span>
        <input type="radio" name="rating" value="1" /><span></span>
        <input type="radio" name="rating" value="2" /><span></span>
        <input type="radio" name="rating" value="3" /><span></span>
        <input type="radio" name="rating" value="4" /><span></span>
        <input type="radio" name="rating" value="5" /><span></span>
    </li>
</ul>

CSS:

.form {
    margin:0;
}

.form li {
    list-style:none;
}

.hide {
    display:none;
}

.rating input[type="radio"] {
    position:absolute;
    filter:alpha(opacity=0);
    -moz-opacity:0;
    -khtml-opacity:0;
    opacity:0;
    cursor:pointer;
    width:17px;
}

.rating span {
    width:24px;
    height:16px;
    line-height:16px;
    padding:1px 22px 1px 0; /* 1px FireFox fix */
    background:url(stars.png) no-repeat -22px 0;
}

.rating input[type="radio"]:checked + span {
    background-position:-22px 0;
}

.rating input[type="radio"]:checked + span ~ span {
    background-position:0 0;
}

Unable to load script from assets index.android.bundle on windows

I had the same issue even when running on a simulator. I did a quick workaround so that I could have the normal dev workflow.

private final ReactNativeHost mReactNativeHost = new ReactNativeHost(this) {
  @Override
  public boolean getUseDeveloperSupport() {
    // return true here to load JS from the packager
    // BuildConfig.DEBUG for me was set to false which meant it
    // it was always trying to load the assets from assets folder.
    return true;
  }

  @Override
  protected String getJSMainModuleName() {
    return "index";
  }
};

Probably will have to revert the change when trying to do a production build.

jQuery $(document).ready and UpdatePanels?

An UpdatePanel completely replaces the contents of the update panel on an update. This means that those events you subscribed to are no longer subscribed because there are new elements in that update panel.

What I've done to work around this is re-subscribe to the events I need after every update. I use $(document).ready() for the initial load, then use Microsoft's PageRequestManager (available if you have an update panel on your page) to re-subscribe every update.

$(document).ready(function() {
    // bind your jQuery events here initially
});

var prm = Sys.WebForms.PageRequestManager.getInstance();

prm.add_endRequest(function() {
    // re-bind your jQuery events here
});

The PageRequestManager is a javascript object which is automatically available if an update panel is on the page. You shouldn't need to do anything other than the code above in order to use it as long as the UpdatePanel is on the page.

If you need more detailed control, this event passes arguments similar to how .NET events are passed arguments (sender, eventArgs) so you can see what raised the event and only re-bind if needed.

Here is the latest version of the documentation from Microsoft: msdn.microsoft.com/.../bb383810.aspx


A better option you may have, depending on your needs, is to use jQuery's .on(). These method are more efficient than re-subscribing to DOM elements on every update. Read all of the documentation before you use this approach however, since it may or may not meet your needs. There are a lot of jQuery plugins that would be unreasonable to refactor to use .delegate() or .on(), so in those cases, you're better off re-subscribing.

How to calculate the median of an array?

public static int median(int[] arr) {
int median = 0;
java.util.Arrays.sort(arr);
        
for (int i=0;i<arr.length;i++) {
            
    if (arr.length % 2 == 1) {
        median = Math.round(arr[arr.length/2]);
    } else {
        median = (arr[(arr.length/2)] + arr[(arr.length/2)-1])/2;
    }
}
return median;

}

Calculate mean and standard deviation from a vector of samples in C++ using Boost

I don't know if Boost has more specific functions, but you can do it with the standard library.

Given std::vector<double> v, this is the naive way:

#include <numeric>

double sum = std::accumulate(v.begin(), v.end(), 0.0);
double mean = sum / v.size();

double sq_sum = std::inner_product(v.begin(), v.end(), v.begin(), 0.0);
double stdev = std::sqrt(sq_sum / v.size() - mean * mean);

This is susceptible to overflow or underflow for huge or tiny values. A slightly better way to calculate the standard deviation is:

double sum = std::accumulate(v.begin(), v.end(), 0.0);
double mean = sum / v.size();

std::vector<double> diff(v.size());
std::transform(v.begin(), v.end(), diff.begin(),
               std::bind2nd(std::minus<double>(), mean));
double sq_sum = std::inner_product(diff.begin(), diff.end(), diff.begin(), 0.0);
double stdev = std::sqrt(sq_sum / v.size());

UPDATE for C++11:

The call to std::transform can be written using a lambda function instead of std::minus and std::bind2nd(now deprecated):

std::transform(v.begin(), v.end(), diff.begin(), [mean](double x) { return x - mean; });

JPA EntityManager: Why use persist() over merge()?

Persist and merge are for two different purposes (they aren't alternatives at all).

(edited to expand differences information)

persist:

  • Insert a new register to the database
  • Attach the object to the entity manager.

merge:

  • Find an attached object with the same id and update it.
  • If exists update and return the already attached object.
  • If doesn't exist insert the new register to the database.

persist() efficiency:

  • It could be more efficient for inserting a new register to a database than merge().
  • It doesn't duplicates the original object.

persist() semantics:

  • It makes sure that you are inserting and not updating by mistake.

Example:

{
    AnyEntity newEntity;
    AnyEntity nonAttachedEntity;
    AnyEntity attachedEntity;

    // Create a new entity and persist it        
    newEntity = new AnyEntity();
    em.persist(newEntity);

    // Save 1 to the database at next flush
    newEntity.setValue(1);

    // Create a new entity with the same Id than the persisted one.
    AnyEntity nonAttachedEntity = new AnyEntity();
    nonAttachedEntity.setId(newEntity.getId());

    // Save 2 to the database at next flush instead of 1!!!
    nonAttachedEntity.setValue(2);
    attachedEntity = em.merge(nonAttachedEntity);

    // This condition returns true
    // merge has found the already attached object (newEntity) and returns it.
    if(attachedEntity==newEntity) {
            System.out.print("They are the same object!");
    }

    // Set 3 to value
    attachedEntity.setValue(3);
    // Really, now both are the same object. Prints 3
    System.out.println(newEntity.getValue());

    // Modify the un attached object has no effect to the entity manager
    // nor to the other objects
    nonAttachedEntity.setValue(42);
}

This way only exists 1 attached object for any register in the entity manager.

merge() for an entity with an id is something like:

AnyEntity myMerge(AnyEntity entityToSave) {
    AnyEntity attached = em.find(AnyEntity.class, entityToSave.getId());
    if(attached==null) {
            attached = new AnyEntity();
            em.persist(attached);
    }
    BeanUtils.copyProperties(attached, entityToSave);

    return attached;
}

Although if connected to MySQL merge() could be as efficient as persist() using a call to INSERT with ON DUPLICATE KEY UPDATE option, JPA is a very high level programming and you can't assume this is going to be the case everywhere.

Simplest way to do a recursive self-join?

The Quassnoi query with a change for large table. Parents with more childs then 10: Formating as str(5) the row_number()

WITH    q AS 
        (
        SELECT  m.*, CAST(str(ROW_NUMBER() OVER (ORDER BY m.ordernum),5) AS VARCHAR(MAX)) COLLATE Latin1_General_BIN AS bc
        FROM    #t m
        WHERE   ParentID =0
        UNION ALL
        SELECT  m.*,  q.bc + '.' + str(ROW_NUMBER()  OVER (PARTITION BY m.ParentID ORDER BY m.ordernum),5) COLLATE Latin1_General_BIN
        FROM    #t m
        JOIN    q
        ON      m.parentID = q.DBID
        )
SELECT  *
FROM    q
ORDER BY
        bc

Paritition array into N chunks with Numpy

Try numpy.array_split.

From the documentation:

>>> x = np.arange(8.0)
>>> np.array_split(x, 3)
    [array([ 0.,  1.,  2.]), array([ 3.,  4.,  5.]), array([ 6.,  7.])]

Identical to numpy.split, but won't raise an exception if the groups aren't equal length.

If number of chunks > len(array) you get blank arrays nested inside, to address that - if your split array is saved in a, then you can remove empty arrays by:

[x for x in a if x.size > 0]

Just save that back in a if you wish.

Difference between "git add -A" and "git add ."

I hope this may add some more clarity.

!The syntax is
git add <limiters> <pathspec>
! Aka
git add (nil/-u/-A) (nil/./pathspec)

Limiters may be -u or -A or nil.

Pathspec may be a filepath or dot, '.' to indicate the current directory.

Important background knowledge about how Git 'adds':

  • Invisible files, those prefixed with a dot, (dotfiles) are never automatically recognized by Git. They are never even listed as 'untracked'.
  • Empty folders are never added by Git. They are never even listed as 'untracked'. (A workaround is to add a blank file, possibly invisible, to the tracked files.)
  • Git status will not display subfolder information, that is, untracked files, unless at least one file in that subfolder is tracked. Before such time, Git considers the entire folder out of scope, a la 'empty'. It is empty of tracked items.
  • Specifying a filespec = '.' (dot), or the current directory, is not recursive unless -A is also specified. Dot refers strictly to the current directory - it omits paths found above and below.

Now, given that knowledge, we can apply the answers above.

The limiters are as follows.

  • -u = --update = subset to tracked files => Add = No; Change = Yes; Delete = Yes. => if the item is tracked.
  • -A = --all (no such -a, which gives syntax error) = superset of all untracked/tracked files , unless in Git before 2.0, wherein if the dot filespec is given, then only that particular folder is considered. => if the item is recognized, git add -A will find it and add it.

The pathspec is as follows.

  • In Git before 2.0, for the two limiters (update and all), the new default is to operate on the entire working tree, instead of the current path (Git 1.9 or earlier),
  • However, in v2.0, the operation can be limited to the current path: just add the explicit dot suffix (which is also valid in Git 1.9 or earlier);

git add -A .

git add -u .

In conclusion, my policy is:

  1. Ensure any hunks/files to be added are accounted for in git status.
  2. If any items are missing, due to invisible files/folders, add them separately.
  3. Have a good .gitignore file so that normally only files of interest are untracked and/or unrecognized.
  4. From the top level of the repository, "git add -A" to add all items. This works in all versions of Git.
  5. Remove any desired items from the index if desired.
  6. If there is a big bug, do 'git reset' to clear the index entirely.

How to include files outside of Docker's build context?

Workaround with links:

ln path/to/file/outside/context/file_to_copy ./file_to_copy

On Dockerfile, simply:

COPY file_to_copy /path/to/file

How can I clear previous output in Terminal in Mac OS X?

A better way to clear the screen from within a script...

If you're using the OS X Terminal app (as stated by the OP), a better approach (thanks to Chris Page's answer to How do I reset the scrollback in the terminal via a shell command?) is just this:

clear && printf '\e[3J'

or more concisely (hat tip to user qiuyi):

printf '\33c\e[3J'

which clears the scrollback buffer as well as the screen. There are other options as well. See Chris Page's answer to How do I reset the scrollback in the terminal via a shell command? for more information.

Original answer

The AppleScript answer given in this thread works, but it has the nasty side effect of clearing any terminal window that happens to be active. This is surprising if you're running the script in one window and trying to get work done in another!

You avoid this by refining the AppleScript to only clear the screen if it is frontmost by doing this (taken from MattiSG's answer to How do I reset the scrollback in the terminal via a shell command?):

osascript -e 'if application "Terminal" is frontmost then tell application "System Events" to keystroke "k" using command down'

... but as when it's not the current window, the output will stack up until it becomes current again, which probably isn't what you want.

How to easily initialize a list of Tuples?

One technique I think is a little easier and that hasn't been mentioned before here:

var asdf = new [] { 
    (Age: 1, Name: "cow"), 
    (Age: 2, Name: "bird")
}.ToList();

I think that's a little cleaner than:

var asdf = new List<Tuple<int, string>> { 
    (Age: 1, Name: "cow"), 
    (Age: 2, Name: "bird")
};

What charset does Microsoft Excel use when saving files?

OOXML files like those that come from Excel 2007 are encoded in UTF-8, according to wikipedia. I don't know about CSV files, but it stands to reason it would use the same format...

Adding multiple class using ng-class

Yes you can have multiple expression to add multiple class in ng-class.

For example:

<div ng-class="{class1:Result.length==2,class2:Result.length==3}"> Dummy Data </div>

Setting Custom ActionBar Title from Fragment

Just to add onto the selected answer, you may also want to add a second method to your main activity. So you would end up with the following methods in your main activity:

public void setActionBarTitle(String title) {
    getSupportActionBar().setTitle(title);
}

public void setActionBarTitle(int resourceId) {
    setActionBarTitle(getResources().getString(resourceId);
}

This will allow you set the title from both a String variable as well as a resource ID such as R.id.this_is_a_string from your strings.xml file. This will also work a little more like how getSupportActionBar().setTitle() works since it allows you to pass in a resource ID.

Syncing Android Studio project with Gradle files

i had this problem yesterday. can you folow the local path in windows explorer?

(C:\users\..\AndroidStudioProjects\SharedPreferencesDemoProject\SharedPreferencesDemo\build\apk\) 

i had to manually create the 'apk' directory in '\build', then the problem was fixed

switch case statement error: case expressions must be constant expression

I would like to mention that, I came across the same situation when I tried adding a library into my project. All of a sudden all switch statements started to show errors!

Now I tried to remove the library which I added, even then it did not work. how ever "when I cleaned the project" all the errors just went off !

Can't get private key with openssl (no start line:pem_lib.c:703:Expecting: ANY PRIVATE KEY)

It looks like you have a certificate in DER format instead of PEM. This is why it works correctly when you provide the -inform PEM command line argument (which tells openssl what input format to expect).

It's likely that your private key is using the same encoding. It looks as if the openssl rsa command also accepts a -inform argument, so try:

openssl rsa -text -in file.key -inform DER

A PEM encoded file is a plain-text encoding that looks something like:

-----BEGIN RSA PRIVATE KEY-----
MIGrAgEAAiEA0tlSKz5Iauj6ud3helAf5GguXeLUeFFTgHrpC3b2O20CAwEAAQIh
ALeEtAIzebCkC+bO+rwNFVORb0bA9xN2n5dyTw/Ba285AhEA9FFDtx4VAxMVB2GU
QfJ/2wIRANzuXKda/nRXIyRw1ArE2FcCECYhGKRXeYgFTl7ch7rTEckCEQDTMShw
8pL7M7DsTM7l3HXRAhAhIMYKQawc+Y7MNE4kQWYe
-----END RSA PRIVATE KEY-----

While DER is a binary encoding format.

Update

Sometimes keys are distributed in PKCS#8 format (which can be either PEM or DER encoded). Try this and see what you get:

openssl pkcs8 -in file.key -inform der

How to download a file using a Java REST service and a data stream

See example here: Input and Output binary streams using JERSEY?

Pseudo code would be something like this (there are a few other similar options in above mentioned post):

@Path("file/")
@GET
@Produces({"application/pdf"})
public StreamingOutput getFileContent() throws Exception {
     public void write(OutputStream output) throws IOException, WebApplicationException {
        try {
          //
          // 1. Get Stream to file from first server
          //
          while(<read stream from first server>) {
              output.write(<bytes read from first server>)
          }
        } catch (Exception e) {
            throw new WebApplicationException(e);
        } finally {
              // close input stream
        }
    }
}

Toggle input disabled attribute using jQuery

Quite a while later, and thanks to @arne, I created this similar small function to handle where the input should be disabled AND hidden, or enabled AND shown:

function toggleInputState(el, on) {
  // 'on' = true(visible) or false(hidden)
  // If a field is to be shown, enable it; if hidden, disable it.
  // Disabling will prevent the field's value from being submitted
  $(el).prop('disabled', !on).toggle(on);
}

Then a jQuery object (such as $('input[name="something"]') ) is simply switched using:

toggleInputState(myElement, myBoolean)

Algorithm to detect overlapping periods

Try this. This method will determine if (two) date spans are overlapping, regardless of the ordering of the method's input arguments. This can also be used with more than two date spans, by individually checking each date span combination (ex. with 3 date spans, run span1 against span2, span2 against span3, and span1 against span3):

public static class HelperFunctions
{
    public static bool AreSpansOverlapping(Tuple<DateTime,DateTime> span1, Tuple<DateTime,DateTime> span2, bool includeEndPoints)
    {
        if (span1 == null || span2 == null)
        {
            return false;
        }
        else if ((new DateTime[] { span1.Item1, span1.Item2, span2.Item1, span2.Item2 }).Any(v => v == DateTime.MinValue))
        {
            return false;
        }
        else
        {
            if (span1.Item1 > span1.Item2)
            {
                span1 = new Tuple<DateTime, DateTime>(span1.Item2, span1.Item1);
            }
            if (span2.Item1 > span2.Item2)
            {
                span2 = new Tuple<DateTime, DateTime>(span2.Item2, span2.Item1);
            }

            if (includeEndPoints)
            {
                return 
                ((
                    (span1.Item1 <= span2.Item1 && span1.Item2 >= span2.Item1) 
                    || (span1.Item1 <= span2.Item2 && span1.Item2 >= span2.Item2)
                ) || (
                    (span2.Item1 <= span1.Item1 && span2.Item2 >= span1.Item1) 
                    || (span2.Item1 <= span1.Item2 && span2.Item2 >= span1.Item2)
                ));
            }
            else
            {
                return 
                ((
                    (span1.Item1 < span2.Item1 && span1.Item2 > span2.Item1) 
                    || (span1.Item1 < span2.Item2 && span1.Item2 > span2.Item2)
                ) || (
                    (span2.Item1 < span1.Item1 && span2.Item2 > span1.Item1) 
                    || (span2.Item1 < span1.Item2 && span2.Item2 > span1.Item2)
                ) || (
                    span1.Item1 == span2.Item1 && span1.Item2 == span2.Item2
                ));
            }
        }
    }
}

Test:

static void Main(string[] args)
{  
    Random r = new Random();

    DateTime d1;
    DateTime d2;
    DateTime d3;
    DateTime d4;

    for (int i = 0; i < 100; i++)
    {
        d1 = new DateTime(2012,1, r.Next(1,31));
        d2 = new DateTime(2012,1, r.Next(1,31));
        d3 = new DateTime(2012,1, r.Next(1,31));
        d4 = new DateTime(2012,1, r.Next(1,31));

        Console.WriteLine("span1 = " + d1.ToShortDateString() + " to " + d2.ToShortDateString());
        Console.WriteLine("span2 = " + d3.ToShortDateString() + " to " + d4.ToShortDateString());
        Console.Write("\t");
        Console.WriteLine(HelperFunctions.AreSpansOverlapping(
            new Tuple<DateTime, DateTime>(d1, d2),
            new Tuple<DateTime, DateTime>(d3, d4),
            true    //or use False, to ignore span's endpoints
            ).ToString());
        Console.WriteLine();
    }

    Console.WriteLine("COMPLETE");
    System.Console.ReadKey();
}

Decimal to Hexadecimal Converter in Java

Another possible solution:

public String DecToHex(int dec){
  char[] hexDigits = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
              'A', 'B', 'C', 'D', 'E', 'F'};
  String hex = "";
  while (dec != 0) {
      int rem = dec % 16;
      hex = hexDigits[rem] + hex;
      dec = dec / 16;
  }
  return hex;
}

How to resolve Error : Showing a modal dialog box or form when the application is not running in UserInteractive mode is not a valid operation

This error can be resolved by adding MessageBoxOptions.ServiceNotification.

MessageBox.Show(msg, "Print Error", System.Windows.Forms.MessageBoxButtons.YesNo, 
   System.Windows.Forms.MessageBoxIcon.Error,     
   System.Windows.Forms.MessageBoxDefaultButton.Button1, 
   System.Windows.Forms.MessageBoxOptions.ServiceNotification); 

But it is not going to show any dialog box if your web application is installed on IIS or server.Because in IIS or server it is hosted on worker process which dont have any desktop.

Call to undefined method mysqli_stmt::get_result

So if the MySQL Native Driver (mysqlnd) driver is not available, and therefore using bind_result and fetch instead of get_result, the code becomes:

include 'conn.php';
$conn = new Connection();
$query = 'SELECT EmailVerified, Blocked FROM users WHERE Email = ? AND SLA = ? AND `Password` = ?';
$stmt = $conn->mysqli->prepare($query);
$stmt->bind_param('sss', $_POST['EmailID'], $_POST['SLA'], $_POST['Password']);
$stmt->execute();
$stmt->bind_result($EmailVerified, $Blocked);
while ($stmt->fetch())
{
   /* Use $EmailVerified and $Blocked */
}
$stmt->close();
$conn->mysqli->close();

CORS jQuery AJAX request

It's easy, you should set server http response header first. The problem is not with your front-end javascript code. You need to return this header:

Access-Control-Allow-Origin:*

or

Access-Control-Allow-Origin:your domain

In Apache config files, the code is like this:

Header set Access-Control-Allow-Origin "*"

In nodejs,the code is like this:

res.setHeader('Access-Control-Allow-Origin','*');

How to find which version of TensorFlow is installed in my system?

If you have TensorFlow 2.x:

sess = tf.compat.v1.Session(config=tf.compat.v1.ConfigProto(log_device_placement=True))

How to set the default value for radio buttons in AngularJS?

In Angular 2 this is how we can set the default value for radio button:

HTML:

<label class="form-check-label">
          <input type="radio" class="form-check-input" name="gender" 
          [(ngModel)]="gender" id="optionsRadios1" value="male">
          Male
</label>

In the Component Class set the value of 'gender' variable equal to the value of radio button:

gender = 'male';

pgadmin4 : postgresql application server could not be contacted.

Happens mostly when you have multiple versions of pgadmin installed or while trying to upgrade. Even I tried everything from killing the "running PID on port 5432" to "changing the server mode". In my case I uninstall postgres and re-install it again on different port(5433). Later, I opened it through cmd(right click on cmd and select "run cmd as an Administrator").enter image description here

Create a OpenSSL certificate on Windows

You can certainly use putty (puttygen.exe) to do that.

Or you can get Cygwin to use the utilities you just described.

The type List is not generic; it cannot be parameterized with arguments [HTTPClient]

Adding java.util.list will resolve your problem because List interface which you are trying to use is part of java.util.list package.

How to check if an array element exists?

You can use isset() for this very thing.

$myArr = array("Name" => "Jonathan");
print (isset($myArr["Name"])) ? "Exists" : "Doesn't Exist" ;

How to calculate number of days between two given dates?

Without using datetime object in python.

# A date has day 'd', month 'm' and year 'y' 
class Date:
    def __init__(self, d, m, y):
            self.d = d
            self.m = m
            self.y = y

# To store number of days in all months from 
# January to Dec. 
monthDays = [31, 28, 31, 30, 31, 30,
                                            31, 31, 30, 31, 30, 31 ]

# This function counts number of leap years 
# before the given date 
def countLeapYears(d):

    years = d.y

    # Check if the current year needs to be considered 
    # for the count of leap years or not 
    if (d.m <= 2) :
            years-= 1

    # An year is a leap year if it is a multiple of 4, 
    # multiple of 400 and not a multiple of 100. 
    return int(years / 4 - years / 100 + years / 400 )


# This function returns number of days between two 
# given dates 
def getDifference(dt1, dt2) :

    # COUNT TOTAL NUMBER OF DAYS BEFORE FIRST DATE 'dt1' 

    # initialize count using years and day 
    n1 = dt1.y * 365 + dt1.d

    # Add days for months in given date 
    for i in range(0, dt1.m - 1) :
            n1 += monthDays[i]

    # Since every leap year is of 366 days, 
    # Add a day for every leap year 
    n1 += countLeapYears(dt1)

    # SIMILARLY, COUNT TOTAL NUMBER OF DAYS BEFORE 'dt2' 

    n2 = dt2.y * 365 + dt2.d
    for i in range(0, dt2.m - 1) :
            n2 += monthDays[i]
    n2 += countLeapYears(dt2)

    # return difference between two counts 
    return (n2 - n1)


# Driver program 
dt1 = Date(31, 12, 2018 )
dt2 = Date(1, 1, 2019 )

print(getDifference(dt1, dt2), "days")

Creating a .dll file in C#.Net

Creating DLL File

  1. Open Visual Studio then select File -> New -> Project

  2. Select Visual C# -> Class library

  3. Compile Project Or Build the solution, to create Dll File

  4. Go to the class library folder (Debug Folder)

Make first letter of a string upper case (with maximum performance)

Since I happened to be working on this also, and was looking around for any ideas, this is the solution I came to. It uses LINQ, and will be able to capitalize the first letter of a string, even if the first occurrence isn't a letter. Here's the extension method I ended up making.

public static string CaptalizeFirstLetter(this string data)
{
    var chars = data.ToCharArray();

    // Find the Index of the first letter
    var charac = data.First(char.IsLetter);
    var i = data.IndexOf(charac);

    // capitalize that letter
    chars[i] = char.ToUpper(chars[i]);

    return new string(chars);
}

I'm sure there's a way to optimize or clean this up a little bit.

What does the "~" (tilde/squiggle/twiddle) CSS selector mean?

It is General sibling combinator and is explained in @Salaman's answer very well.

What I did miss is Adjacent sibling combinator which is + and is closely related to ~.

example would be

.a + .b {
  background-color: #ff0000;
}

<ul>
  <li class="a">1st</li>
  <li class="b">2nd</li>
  <li>3rd</li>
  <li class="b">4th</li>
  <li class="a">5th</li>
</ul>
  • Matches elements that are .b
  • Are adjacent to .a
  • After .a in HTML

In example above it will mark 2nd li but not 4th.

_x000D_
_x000D_
   .a + .b {_x000D_
     background-color: #ff0000;_x000D_
   }
_x000D_
<ul>_x000D_
  <li class="a">1st</li>_x000D_
  <li class="b">2nd</li>_x000D_
  <li>3rd</li>_x000D_
  <li class="b">4th</li>_x000D_
  <li class="a">5th</li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

JSFiddle

How do I specify the exit code of a console application in .NET?

Use this code

Environment.Exit(0);

use 0 as the int if you don't want to return anything.

C# ASP.NET Send Email via TLS

TLS (Transport Level Security) is the slightly broader term that has replaced SSL (Secure Sockets Layer) in securing HTTP communications. So what you are being asked to do is enable SSL.

PDOException SQLSTATE[HY000] [2002] No such file or directory

Check your port carefully . In my case it was 8889 and i am using 8888. change "DB_HOST" from "localhost" to "127.0.0.1" and vice versa

How can I remove the "No file chosen" tooltip from a file input in Chrome?

Directly you can't modify much about input[type=file].

Make input type file opacity:0 and try to place a relative element [div/span/button] over it with custom CSS

Try this http://jsfiddle.net/gajjuthechamp/pvyVZ/8/

Running Bash commands in Python

It is possible you use the bash program, with the parameter -c for execute the commands:

bashCommand = "cwm --rdf test.rdf --ntriples > test.nt"
output = subprocess.check_output(['bash','-c', bashCommand])

How do I query between two dates using MySQL?

Your query should have date as

select * from table between `lowerdate` and `upperdate`

try

SELECT * FROM `objects` 
WHERE  (date_field BETWEEN '2010-01-30 14:15:55' AND '2010-09-29 10:15:55')

How to convert a private key to an RSA private key?

Newer versions of OpenSSL say BEGIN PRIVATE KEY because they contain the private key + an OID that identifies the key type (this is known as PKCS8 format). To get the old style key (known as either PKCS1 or traditional OpenSSL format) you can do this:

openssl rsa -in server.key -out server_new.key

Alternately, if you have a PKCS1 key and want PKCS8:

openssl pkcs8 -topk8 -nocrypt -in privkey.pem

Change a Django form field to a hidden field

Firstly, if you don't want the user to modify the data, then it seems cleaner to simply exclude the field. Including it as a hidden field just adds more data to send over the wire and invites a malicious user to modify it when you don't want them to. If you do have a good reason to include the field but hide it, you can pass a keyword arg to the modelform's constructor. Something like this perhaps:

class MyModelForm(forms.ModelForm):
    class Meta:
        model = MyModel
    def __init__(self, *args, **kwargs):
        from django.forms.widgets import HiddenInput
        hide_condition = kwargs.pop('hide_condition',None)
        super(MyModelForm, self).__init__(*args, **kwargs)
        if hide_condition:
            self.fields['fieldname'].widget = HiddenInput()
            # or alternately:  del self.fields['fieldname']  to remove it from the form altogether.

Then in your view:

form = MyModelForm(hide_condition=True)

I prefer this approach to modifying the modelform's internals in the view, but it's a matter of taste.

How to find and replace string?

Do we really need a Boost library for seemingly such a simple task?

To replace all occurences of a substring use this function:

std::string ReplaceString(std::string subject, const std::string& search,
                          const std::string& replace) {
    size_t pos = 0;
    while ((pos = subject.find(search, pos)) != std::string::npos) {
         subject.replace(pos, search.length(), replace);
         pos += replace.length();
    }
    return subject;
}

If you need performance, here is an optimized function that modifies the input string, it does not create a copy of the string:

void ReplaceStringInPlace(std::string& subject, const std::string& search,
                          const std::string& replace) {
    size_t pos = 0;
    while ((pos = subject.find(search, pos)) != std::string::npos) {
         subject.replace(pos, search.length(), replace);
         pos += replace.length();
    }
}

Tests:

std::string input = "abc abc def";
std::cout << "Input string: " << input << std::endl;

std::cout << "ReplaceString() return value: " 
          << ReplaceString(input, "bc", "!!") << std::endl;
std::cout << "ReplaceString() input string not modified: " 
          << input << std::endl;

ReplaceStringInPlace(input, "bc", "??");
std::cout << "ReplaceStringInPlace() input string modified: " 
          << input << std::endl;

Output:

Input string: abc abc def
ReplaceString() return value: a!! a!! def
ReplaceString() input string not modified: abc abc def
ReplaceStringInPlace() input string modified: a?? a?? def

How do I return the response from an asynchronous call?

If you're not using jQuery in your code, this answer is for you

Your code should be something along the lines of this:

function foo() {
    var httpRequest = new XMLHttpRequest();
    httpRequest.open('GET', "/echo/json");
    httpRequest.send();
    return httpRequest.responseText;
}

var result = foo(); // always ends up being 'undefined'

Felix Kling did a fine job writing an answer for people using jQuery for AJAX, I've decided to provide an alternative for people who aren't.

(Note, for those using the new fetch API, Angular or promises I've added another answer below)


What you're facing

This is a short summary of "Explanation of the problem" from the other answer, if you're not sure after reading this, read that.

The A in AJAX stands for asynchronous. That means sending the request (or rather receiving the response) is taken out of the normal execution flow. In your example, .send returns immediately and the next statement, return result;, is executed before the function you passed as success callback was even called.

This means when you're returning, the listener you've defined did not execute yet, which means the value you're returning has not been defined.

Here is a simple analogy

function getFive(){ 
    var a;
    setTimeout(function(){
         a=5;
    },10);
    return a;
}

(Fiddle)

The value of a returned is undefined since the a=5 part has not executed yet. AJAX acts like this, you're returning the value before the server got the chance to tell your browser what that value is.

One possible solution to this problem is to code re-actively , telling your program what to do when the calculation completed.

function onComplete(a){ // When the code completes, do this
    alert(a);
}

function getFive(whenDone){ 
    var a;
    setTimeout(function(){
         a=5;
         whenDone(a);
    },10);
}

This is called CPS. Basically, we're passing getFive an action to perform when it completes, we're telling our code how to react when an event completes (like our AJAX call, or in this case the timeout).

Usage would be:

getFive(onComplete);

Which should alert "5" to the screen. (Fiddle).

Possible solutions

There are basically two ways how to solve this:

  1. Make the AJAX call synchronous (lets call it SJAX).
  2. Restructure your code to work properly with callbacks.

1. Synchronous AJAX - Don't do it!!

As for synchronous AJAX, don't do it! Felix's answer raises some compelling arguments about why it's a bad idea. To sum it up, it'll freeze the user's browser until the server returns the response and create a very bad user experience. Here is another short summary taken from MDN on why:

XMLHttpRequest supports both synchronous and asynchronous communications. In general, however, asynchronous requests should be preferred to synchronous requests for performance reasons.

In short, synchronous requests block the execution of code... ...this can cause serious issues...

If you have to do it, you can pass a flag: Here is how:

var request = new XMLHttpRequest();
request.open('GET', 'yourURL', false);  // `false` makes the request synchronous
request.send(null);
 
if (request.status === 200) {// That's HTTP for 'ok'
  console.log(request.responseText);
}

2. Restructure code

Let your function accept a callback. In the example code foo can be made to accept a callback. We'll be telling our code how to react when foo completes.

So:

var result = foo();
// code that depends on `result` goes here

Becomes:

foo(function(result) {
    // code that depends on `result`
});

Here we passed an anonymous function, but we could just as easily pass a reference to an existing function, making it look like:

function myHandler(result) {
    // code that depends on `result`
}
foo(myHandler);

For more details on how this sort of callback design is done, check Felix's answer.

Now, let's define foo itself to act accordingly

function foo(callback) {
    var httpRequest = new XMLHttpRequest();
    httpRequest.onload = function(){ // when the request is loaded
       callback(httpRequest.responseText);// we're calling our method
    };
    httpRequest.open('GET', "/echo/json");
    httpRequest.send();
}

(fiddle)

We have now made our foo function accept an action to run when the AJAX completes successfully, we can extend this further by checking if the response status is not 200 and acting accordingly (create a fail handler and such). Effectively solving our issue.

If you're still having a hard time understanding this read the AJAX getting started guide at MDN.

Fixed height and width for bootstrap carousel

Apply following style to carousel listbox.

_x000D_
_x000D_
<div class="carousel-inner" role="listbox" style=" width:100%; height: 500px !important;">_x000D_
_x000D_
..._x000D_
_x000D_
</div
_x000D_
_x000D_
_x000D_

Pass variables from servlet to jsp

This is an servlet code which contain a string variable a. the value for a is getting from an html page with form. then set the variable into the request object. then pass it to jsp using forward and requestdispatcher methods.

String a=req.getParameter("username");
req.setAttribute("name", a);
RequestDispatcher rd=req.getRequestDispatcher("/login.jsp");
rd.forward(req, resp);

in jsp follow these steps shown below in the program

<%String name=(String)request.getAttribute("name");
out.print("your name"+name);%>

Input group - two inputs close to each other

Create a input-group-glue class with this:

_x000D_
_x000D_
.input-group-glue {_x000D_
  width: 0;_x000D_
  display: table-cell;_x000D_
}_x000D_
_x000D_
.input-group-glue + .form-control {_x000D_
  border-left: none;_x000D_
}
_x000D_
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css" rel="stylesheet"/>_x000D_
<div class="input-group">_x000D_
  <input type="text" class="form-control" value="test1" />_x000D_
  <span class="input-group-glue"></span>_x000D_
  <input type="text" class="form-control" value="test2" />_x000D_
  <span class="input-group-glue"></span>_x000D_
  <input type="text" class="form-control" value="test2" />_x000D_
</div>
_x000D_
_x000D_
_x000D_

How to access Spring MVC model object in javascript file?

You can't access java objects from JavaScript because there are no objects on client side. It only receives plain HTML page (hidden fields can help but it's not very good approach).

I suggest you to use ajax and @ResponseBody.

Get UTC time and local time from NSDate object

My Xcode Version 6.1.1 (6A2008a)

In playground, test like this:

// I'm in East Timezone 8
let x = NSDate() //Output:"Dec 29, 2014, 11:37 AM"
let y = NSDate.init() //Output:"Dec 29, 2014, 11:37 AM"
println(x) //Output:"2014-12-29 03:37:24 +0000"


// seconds since 2001
x.hash //Output:441,517,044
x.hashValue //Output:441,517,044
x.timeIntervalSinceReferenceDate //Output:441,517,044.875367

// seconds since 1970
x.timeIntervalSince1970 //Output:1,419,824,244.87537

Inline functions in C#?

C# does not support inline methods (or functions) in the way dynamic languages like python do. However anonymous methods and lambdas can be used for similar purposes including when you need to access a variable in the containing method like in the example below.

static void Main(string[] args)
{
    int a = 1;

    Action inline = () => a++;
    inline();
    //here a = 2
}

How do you monitor network traffic on the iPhone?

You didnt specify the platform you use, so I assume it's a Mac ;-)

What I do is use a proxy. I use SquidMan, a standalone implementation of Squid

I start SquidMan on the Mac, then on the iPhone I enter the Proxy params in the General/Wifi Settings.

Then I can watch the HTTP trafic in the Console App, looking at the squid-access.log

If I need more infos, I switch to tcpdump, but I suppose WireShark should work too.

How to retrieve a user environment variable in CMake (Windows)

Environment variables (that you modify using the System Properties) are only propagated to subshells when you create a new subshell.

If you had a command line prompt (DOS or cygwin) open when you changed the User env vars, then they won't show up.

You need to open a new command line prompt after you change the user settings.

The equivalent in Unix/Linux is adding a line to your .bash_rc: you need to start a new shell to get the values.

How to print Unicode character in C++?

Another solution in Linux:

string a = "?";
cout << "? = \xd0\xa4 = " << hex
     << int(static_cast<unsigned char>(a[0]))
     << int(static_cast<unsigned char>(a[1])) << " (" << a.length() << "B)" << endl;

string b = "v";
cout << "v = \xe2\x88\x9a = " << hex
     << int(static_cast<unsigned char>(b[0]))
     << int(static_cast<unsigned char>(b[1]))
     << int(static_cast<unsigned char>(b[2])) << " (" << b.length() << "B)" << endl;

Rotating and spacing axis labels in ggplot2

Use coord_flip()

data(diamonds)
diamonds$cut <- paste("Super Dee-Duper",as.character(diamonds$cut))

qplot(cut, carat, data = diamonds, geom = "boxplot") +
  coord_flip()

enter image description here


Add str_wrap()

# wrap text to no more than 15 spaces
library(stringr)
diamonds$cut2 <- str_wrap(diamonds$cut, width = 15)
qplot(cut2, carat, data = diamonds, geom = "boxplot") +
  coord_flip()

enter image description here


In Ch 3.9 of R for Data Science, Wickham and Grolemund speak to this exact question:

coord_flip() switches the x and y axes. This is useful (for example), if you want horizontal boxplots. It’s also useful for long labels: it’s hard to get them to fit without overlapping on the x-axis.

difference between $query>num_rows() and $this->db->count_all_results() in CodeIgniter & which one is recommended

We can also use

return $this->db->count_all('table_name');  

or

$this->db->from('table_name');
return $this->db->count_all_result();

or

return $this->db->count_all_result('table_name');

or

$query = $this->db->query('select * from tab');  
return $query->num_rows();

Bootstrap 3: Scroll bars

You need to use overflow option like below:

.nav{
    max-height: 300px;
    overflow-y: scroll; 
}

Change the height according to amount of items you need to show

Microsoft Azure: How to create sub directory in a blob container

As @Egon mentioned above, there is no real folder management in BLOB storage.

You can achieve some features of a file system using '/' in the file name, but this has many limitations (for example, what happen if you need to rename a "folder"?).

As a general rule, I would keep my files as flat as possible in a container, and have my application manage whatever structure I want to expose to the end users (for example manage a nested folder structure in my database, have a record for each file, referencing the BLOB using container-name and file-name).

Running Tensorflow in Jupyter Notebook

  1. install tensorflow by running these commands in anoconda shell or in console:

    conda create -n tensorflow python=3.5
    activate tensorflow
    conda install pandas matplotlib jupyter notebook scipy scikit-learn
    pip install tensorflow
    
  2. close the console and reopen it and type these commands:

    activate tensorflow 
    jupyter notebook 
    

Is it possible to sort a ES6 map object?

Unfortunately, not really implemented in ES6. You have this feature with OrderedMap.sort() from ImmutableJS or _.sortBy() from Lodash.

How to Create a real one-to-one relationship in SQL Server

A 1 to 1 relationship is very much possible. Even if the relationship diagram doesn't show the 1 to 1 relationship explicitly. If you implement it as below, it will function as a one to one relationship.

I will use a basic example to explain the concept where a single person can only have a single passport. This example works perfectly in MS Access. For the SQL Server version follow this link.

Remember that in MS Access, SQL scripts can only be run one at a time and not as displayed here in sequence.

CREATE TABLE Person
(
Pk_Person_Id INT PRIMARY KEY,
Name VARCHAR(255),
EmailId VARCHAR(255),
);

CREATE TABLE PassportDetails
(
Pk_Passport_Id INT PRIMARY KEY,
Passport_Number VARCHAR(255),
Fk_Person_Id INT NOT NULL UNIQUE, 
FOREIGN KEY(Fk_Person_Id) REFERENCES Person(Pk_Person_Id)
);

JQuery - Call the jquery button click event based on name property

You have to use the jquery attribute selector. You can read more here:

http://api.jquery.com/attribute-equals-selector/

In your case it should be:

$('input[name="btnName"]')

How to stop a PowerShell script on the first error?

You should be able to accomplish this by using the statement $ErrorActionPreference = "Stop" at the beginning of your scripts.

The default setting of $ErrorActionPreference is Continue, which is why you are seeing your scripts keep going after errors occur.

Javascript one line If...else...else if statement

I know this is an old thread, but thought I'd put my two cents in. Ternary operators are able to be nested in the following fashion:

var variable = conditionA ? valueA : (conditionB ? valueB: (conditionC ? valueC : valueD));

Example:

var answer = value === 'foo' ? 1 :
    (value === 'bar' ? 2 : 
        (value === 'foobar' ? 3 : 0));

Convert alphabet letters to number in Python

def letter_to_int(letter):
    alphabet = list('abcdefghijklmnopqrstuvwxyz')
    return alphabet.index(letter) + 1

here, the index (x) function returns the position value of x if the list contains x.

How to pass the password to su/sudo/ssh without overriding the TTY?

Maybe you can use an expect command?:

expect -c 'spawn ssh [email protected];expect password;send "your-password\n";interact

That command gives the password automatically.

Get the contents of a table row with a button click

Here is the complete code for simple example of delegate

<!DOCTYPE html>
<html lang="en">
<head>
  <title>Bootstrap Example</title>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>

</head>
<body>

<div class="container">
  <h2>Striped Rows</h2>
  <p>The .table-striped class adds zebra-stripes to a table:</p>            
  <table class="table table-striped">
    <thead>
      <tr>
        <th>Firstname</th>
        <th>Lastname</th>
        <th>Email</th>

      </tr>
    </thead>
    <tbody>
      <tr>
        <td>John</td>
        <td>Doe</td>
        <td>[email protected]</td>
        <td>click</td>
      </tr>
      <tr>
        <td>Mary</td>
        <td>Moe</td>
        <td>[email protected]</td>
        <td>click</td>
      </tr>
      <tr>
        <td>July</td>
        <td>Dooley</td>
        <td>[email protected]</td>
        <td>click</td>
      </tr>

    </tbody>
  </table>
  <script>
  $(document).ready(function(){
  $("div").delegate("table tbody tr td:nth-child(4)", "click", function(){
  var $row = $(this).closest("tr"),        // Finds the closest row <tr> 
    $tds = $row.find("td:nth-child(2)");
     $.each($tds, function() {
        console.log($(this).text());
        var x = $(this).text();
        alert(x);
    });
    });
});
  </script>
</div>

</body>
</html>

Convert string to date then format the date

tl;dr

LocalDate.parse( "2011-01-01" )
         .format( DateTimeFormatter.ofPattern( "MM-dd-uuuu" ) ) 

java.time

The other Answers are now outdated. The troublesome old date-time classes such as java.util.Date, java.util.Calendar, and java.text.SimpleDateFormat are now legacy, supplanted by the java.time classes.

ISO 8601

The input string 2011-01-01 happens to comply with the ISO 8601 standard formats for date-time text. The java.time classes use these standard formats by default when parsing/generating strings. So no need to specify a formatting pattern.

LocalDate

The LocalDate class represents a date-only value without time-of-day and without time zone.

LocalDate ld = LocalDate.parse( "2011-01-01" ) ;

Generate a String in the same format by calling toString.

String output = ld.toString() ;

2011-01-01

DateTimeFormatter

To parse/generate other formats, use a DateTimeFormatter.

DateTimeFormatter f = DateTimeFormatter.ofPattern( "MM-dd-uuuu" ) ;
String output = ld.format( f ) ;

01-01-2011


About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date, Calendar, & SimpleDateFormat.

The Joda-Time project, now in maintenance mode, advises migration to the java.time classes.

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations. Specification is JSR 310.

Where to obtain the java.time classes?

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.

Using jQuery to see if a div has a child with a certain class

Use the children funcion of jQuery.

$("#text-field").keydown(function(event) {
    if($('#popup').children('p.filled-text').length > 0) {
        console.log("Found");
     }
});

$.children('').length will return the count of child elements which match the selector.

How to use a keypress event in AngularJS?

you can use ng-keydown , ng-keyup , ng-press such as this .

to triger a function :

   <input type="text" ng-keypress="function()"/>

or if you have one condion such as when he press escape (27 is the key code for escape)

 <form ng-keydown=" event.which=== 27?cancelSplit():0">
....
</form>

Error during installing HAXM, VT-X not working

I really hated this awful problem after upgrading Windows 10 Anniversary Update (version 1607). It's just about Driver Signing Changes in Windows 10. If you force install HAXM, you have to disable Driver Signature Enforcement too.

  1. Restart W10 in Safe Mode.
  2. Enter Troubleshoot.
  3. Advanced options>Startup Settings.
  4. Choose "Disable driver signature enforcement"
  5. When Windows 10 loaded, install HAXM latest version.

How to use underscore.js as a template engine?

I wanted to share one more important finding.

use of <%= variable => would result in cross-site scripting vulnerability. So its more safe to use <%- variable -> instead.

We had to replace <%= with <%- to prevent cross-site scripting attacks. Not sure, whether this will it have any impact on the performance

How to export database schema in Oracle to a dump file

It depends on which version of Oracle? Older versions require exp (export), newer versions use expdp (data pump); exp was deprecated but still works most of the time.

Before starting, note that Data Pump exports to the server-side Oracle "directory", which is an Oracle symbolic location mapped in the database to a physical location. There may be a default directory (DATA_PUMP_DIR), check by querying DBA_DIRECTORIES:

  SQL> select * from dba_directories;

... and if not, create one

  SQL> create directory DATA_PUMP_DIR as '/oracle/dumps';
  SQL> grant all on directory DATA_PUMP_DIR to myuser;    -- DBAs dont need this grant

Assuming you can connect as the SYSTEM user, or another DBA, you can export any schema like so, to the default directory:

 $ expdp system/manager schemas=user1 dumpfile=user1.dpdmp

Or specifying a specific directory, add directory=<directory name>:

 C:\> expdp system/manager schemas=user1 dumpfile=user1.dpdmp directory=DUMPDIR

With older export utility, you can export to your working directory, and even on a client machine that is remote from the server, using:

 $ exp system/manager owner=user1 file=user1.dmp

Make sure the export is done in the correct charset. If you haven't setup your environment, the Oracle client charset may not match the DB charset, and Oracle will do charset conversion, which may not be what you want. You'll see a warning, if so, then you'll want to repeat the export after setting NLS_LANG environment variable so the client charset matches the database charset. This will cause Oracle to skip charset conversion.

Example for American UTF8 (UNIX):

 $ export NLS_LANG=AMERICAN_AMERICA.AL32UTF8

Windows uses SET, example using Japanese UTF8:

 C:\> set NLS_LANG=Japanese_Japan.AL32UTF8

More info on Data Pump here: http://docs.oracle.com/cd/B28359_01/server.111/b28319/dp_export.htm#g1022624

How can I use Async with ForEach?

This is method I created to handle async scenarios with ForEach.

  • If one of tasks fails then other tasks will continue their execution.
  • You have ability to add function that will be executed on every exception.
  • Exceptions are being collected as aggregateException at the end and are available for you.
  • Can handle CancellationToken
 public static class ParallelExecutor
    {
        /// <summary>
        /// Executes asynchronously given function on all elements of given enumerable with task count restriction.
        /// Executor will continue starting new tasks even if one of the tasks throws. If at least one of the tasks throwed exception then <see cref="AggregateException"/> is throwed at the end of the method run.
        /// </summary>
        /// <typeparam name="T">Type of elements in enumerable</typeparam>
        /// <param name="maxTaskCount">The maximum task count.</param>
        /// <param name="enumerable">The enumerable.</param>
        /// <param name="asyncFunc">asynchronous function that will be executed on every element of the enumerable. MUST be thread safe.</param>
        /// <param name="onException">Acton that will be executed on every exception that would be thrown by asyncFunc. CAN be thread unsafe.</param>
        /// <param name="cancellationToken">The cancellation token.</param>
        public static async Task ForEachAsync<T>(int maxTaskCount, IEnumerable<T> enumerable, Func<T, Task> asyncFunc, Action<Exception> onException = null, CancellationToken cancellationToken = default)
        {
            using var semaphore = new SemaphoreSlim(initialCount: maxTaskCount, maxCount: maxTaskCount);

            // This `lockObject` is used only in `catch { }` block.
            object lockObject = new object();
            var exceptions = new List<Exception>();
            var tasks = new Task[enumerable.Count()];
            int i = 0;

            try
            {
                foreach (var t in enumerable)
                {
                    await semaphore.WaitAsync(cancellationToken);
                    tasks[i++] = Task.Run(
                        async () =>
                        {
                            try
                            {
                                await asyncFunc(t);
                            }
                            catch (Exception e)
                            {
                                if (onException != null)
                                {
                                    lock (lockObject)
                                    {
                                        onException.Invoke(e);
                                    }
                                }

                                // This exception will be swallowed here but it will be collected at the end of ForEachAsync method in order to generate AggregateException.
                                throw;
                            }
                            finally
                            {
                                semaphore.Release();
                            }
                        }, cancellationToken);

                    if (cancellationToken.IsCancellationRequested)
                    {
                        break;
                    }
                }
            }
            catch (OperationCanceledException e)
            {
                exceptions.Add(e);
            }

            foreach (var t in tasks)
            {
                if (cancellationToken.IsCancellationRequested)
                {
                    break;
                }

                // Exception handling in this case is actually pretty fast.
                // https://gist.github.com/shoter/d943500eda37c7d99461ce3dace42141
                try
                {
                    await t;
                }
#pragma warning disable CA1031 // Do not catch general exception types - we want to throw that exception later as aggregate exception. Nothing wrong here.
                catch (Exception e)
#pragma warning restore CA1031 // Do not catch general exception types
                {
                    exceptions.Add(e);
                }
            }

            if (exceptions.Any())
            {
                throw new AggregateException(exceptions);
            }
        }
    }

Android Studio don't generate R.java for my import project

Had the same problem and solved it by:

  1. running / building the project (it was deployed to the device, in my case)
  2. right-clicking on the Project/Module/build folder
  3. choose: Synchronize 'build' - then i found

Project/Module/build/source/r/debug/package/R.java

Probably it was even there before the project was build, but I didn't test that.

I hope this was helpful, even though the answer comes a bit late and by now the bug with the

Settings->Compiler->[ ] Use external build

should be fixed afaik ;-)

How to find the day, month and year with moment.js

I am getting day, month and year using dedicated functions moment().date(), moment().month() and moment().year() of momentjs.

_x000D_
_x000D_
let day = moment('2014-07-28', 'YYYY/MM/DD').date();_x000D_
let month = 1 + moment('2014-07-28', 'YYYY/MM/DD').month();_x000D_
let year = moment('2014-07-28', 'YYYY/MM/DD').year();_x000D_
_x000D_
console.log(day);_x000D_
console.log(month);_x000D_
console.log(year);
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.22.1/moment.min.js"></script>
_x000D_
_x000D_
_x000D_

I don't know why there are 48 upvotes for @Chris Schmitz answer which is not 100% correct.

Month is in form of array and starts from 0 so to get exact value we should use 1 + moment().month()

ExecuteNonQuery: Connection property has not been initialized.

Opening and closing the connection takes a lot of time. And use the "using" as another member suggested. I changed your code slightly, but put the SQL creation and opening and closing OUTSIDE your loop. Which should speed up the execution a bit.

  static void Main()
        {
            EventLog alog = new EventLog();
            alog.Log = "Application";
            alog.MachineName = ".";
            /*  ALSO: USE the USING Statement as another member suggested
            using (SqlConnection connection1 = new SqlConnection(@"Data Source=.\sqlexpress;Initial Catalog=syslog2;Integrated Security=True")
            {

                using (SqlCommand comm = new SqlCommand("INSERT INTO Application VALUES (@EventLog, @TimeGenerated, @EventType, @SourceName, @ComputerName, @InstanceId, @Message) ", connection1))
                {
                    // add the code in here
                    // AND REMEMBER: connection1.Open();

                }
            }*/
            SqlConnection connection1 = new SqlConnection(@"Data Source=.\sqlexpress;Initial Catalog=syslog2;Integrated Security=True");
            SqlDataAdapter cmd = new SqlDataAdapter();
            // Do it one line
            cmd.InsertCommand = new SqlCommand("INSERT INTO Application VALUES (@EventLog, @TimeGenerated, @EventType, @SourceName, @ComputerName, @InstanceId, @Message) ", connection1);
            // OR YOU CAN DO IN SEPARATE LINE :
            // cmd.InsertCommand.Connection = connection1;
            connection1.Open();

            // CREATE YOUR SQLCONNECTION ETC OUTSIDE YOUR FOREACH LOOP
            foreach (EventLogEntry entry in alog.Entries)
            {
                cmd.InsertCommand.Parameters.Add("@EventLog", SqlDbType.VarChar).Value = alog.Log;
                cmd.InsertCommand.Parameters.Add("@TimeGenerated", SqlDbType.DateTime).Value = entry.TimeGenerated;
                cmd.InsertCommand.Parameters.Add("@EventType", SqlDbType.VarChar).Value = entry.EntryType;
                cmd.InsertCommand.Parameters.Add("@SourceName", SqlDbType.VarChar).Value = entry.Source;
                cmd.InsertCommand.Parameters.Add("@ComputerName", SqlDbType.VarChar).Value = entry.MachineName;
                cmd.InsertCommand.Parameters.Add("@InstanceId", SqlDbType.VarChar).Value = entry.InstanceId;
                cmd.InsertCommand.Parameters.Add("@Message", SqlDbType.VarChar).Value = entry.Message;
                int rowsAffected = cmd.InsertCommand.ExecuteNonQuery();
            }
            connection1.Close(); // AND CLOSE IT ONCE, AFTER THE LOOP
        }

How can I create a product key for my C# application?

There are some tools and API's available for it. However, I do not think you'll find one for free ;)

There is for instance the OLicense suite: http://www.olicense.de/index.php?lang=en

DIV table colspan: how?

you just use the :nth-child(num) in css for add the colspan like

 <style>
 div.table
  {
  display:table;
  width:100%;
  }
 div.table-row
  {
   display:table-row;
  }
 div.table-td
 {
  display:table-cell;
 }
 div.table-row:nth-child(1)
 {
  display:block;
 }
</style>
<div class="table>
    <div class="table-row">test</div>
    <div class="table-row">
      <div class="table-td">data1</div>
      <div class="table-td">data2</div>
    </div>
</div>

Filter by process/PID in Wireshark

You could match the port numbers from wireshark up to port numbers from, say, netstat which will tell you the PID of a process listening on that port.

react-router go back a page how do you configure history?

One Line Answer:

window.history.back();

Bootstrap $('#myModal').modal('show') is not working

Please also make sure that the modal div is nested inside your <body> element.

Dialogs / AlertDialogs: How to "block execution" while dialog is up (.NET-style)

PasswordDialog dlg = new PasswordDialog(this);

if(dlg.showDialog() == DialogResult.OK)

{

    //blabla, anything your self

}


public class PasswordDialog extends Dialog
{
    int dialogResult;
    Handler mHandler ;

    public PasswordDialog(Activity context, String mailName, boolean retry)
    {

        super(context);
        setOwnerActivity(context);
        onCreate();
        TextView promptLbl = (TextView) findViewById(R.id.promptLbl);
        promptLbl.setText("Input password/n" + mailName);
    }
    public int getDialogResult()
    {
        return dialogResult;
    }
    public void setDialogResult(int dialogResult)
    {
        this.dialogResult = dialogResult;
    }
    /** Called when the activity is first created. */

    public void onCreate() {
        setContentView(R.layout.password_dialog);
        findViewById(R.id.cancelBtn).setOnClickListener(new android.view.View.OnClickListener() {

            @Override
            public void onClick(View paramView)
            {
                endDialog(DialogResult.CANCEL);
            }
            });
        findViewById(R.id.okBtn).setOnClickListener(new android.view.View.OnClickListener() {

            @Override
            public void onClick(View paramView)
            {
                endDialog(DialogResult.OK);
            }
            });
        }

    public void endDialog(int result)
    {
        dismiss();
        setDialogResult(result);
        Message m = mHandler.obtainMessage();
        mHandler.sendMessage(m);
    }

    public int showDialog()
    {
        mHandler = new Handler() {
            @Override
              public void handleMessage(Message mesg) {
                  // process incoming messages here
                //super.handleMessage(msg);
                throw new RuntimeException();
              }
          };
        super.show();
        try {
            Looper.getMainLooper().loop();
        }
        catch(RuntimeException e2)
        {
        }
        return dialogResult;
    }

}

CSS Calc Viewport Units Workaround?

Doing this with a CSS Grid is pretty easy. The trick is to set the grid's height to 100vw, then assign one of the rows to 75vw, and the remaining one (optional) to 1fr. This gives you, from what I assume is what you're after, a ratio-locked resizing container.

Example here: https://codesandbox.io/s/21r4z95p7j

You can even utilize the bottom gutter space if you so choose, simply by adding another "item".

Edit: StackOverflow's built-in code runner has some side effects. Pop over to the codesandbox link and you'll see the ratio in action.

_x000D_
_x000D_
body {_x000D_
  margin: 0;_x000D_
  padding: 0;_x000D_
  background-color: #334;_x000D_
  color: #eee;_x000D_
}_x000D_
_x000D_
.main {_x000D_
  min-height: 100vh;_x000D_
  min-width: 100vw;_x000D_
  display: grid;_x000D_
  grid-template-columns: 100%;_x000D_
  grid-template-rows: 75vw 1fr;_x000D_
}_x000D_
_x000D_
.item {_x000D_
  background-color: #558;_x000D_
  padding: 2px;_x000D_
  margin: 1px;_x000D_
}_x000D_
_x000D_
.item.dead {_x000D_
  background-color: transparent;_x000D_
}
_x000D_
<html>_x000D_
  <head>_x000D_
    <title>Parcel Sandbox</title>_x000D_
    <meta charset="UTF-8" />_x000D_
    <link rel="stylesheet" href="src/index.css" />_x000D_
  </head>_x000D_
_x000D_
  <body>_x000D_
    <div id="app">_x000D_
      <div class="main">_x000D_
        <div class="item">Item 1</div>_x000D_
        <!-- <div class="item dead">Item 2 (dead area)</div> -->_x000D_
      </div>_x000D_
    </div>_x000D_
  </body>_x000D_
</html>
_x000D_
_x000D_
_x000D_

var self = this?

I think it actually depends on what are you going to do inside your doSomething function. If you are going to access MyObject properties using this keyword then you have to use that. But I think that the following code fragment will also work if you are not doing any special things using object(MyObject) properties.

function doSomething(){
  .........
}

$("#foobar").ready('click', function(){

});

How do I install imagemagick with homebrew?

You could try:

brew update && brew install imagemagick

The remote certificate is invalid according to the validation procedure

You must check the certificate hash code.

ServicePointManager.ServerCertificateValidationCallback = (sender, certificate, chain,
    errors) =>
        {
            var hashString = certificate.GetCertHashString();
            if (hashString != null)
            {
                var certHashString = hashString.ToLower();
                return certHashString == "dec2b525ddeemma8ccfaa8df174455d6e38248c5";
            }
            return false;
        };

How to send image to PHP file using Ajax?

<html>
  <head>
    <script src="http://code.jquery.com/jquery-1.9.1.js"></script>
    <script>
      $(function () {

        $('#abc').on('submit', function (e) {

          e.preventDefault();

          $.ajax({
            url: 'post.php',
            method:'POST',
            data: new FormData(this),
            contentType: false,
            cache:false,
            processData:false,
            success: function (data) {
              alert(data);
              location.reload();
            }
          });

        });

      });
    </script>
  </head>
  <body>
    <form enctype= "multipart/form-data" id="abc">
      <input name="fname" ><br>
      <input name="lname"><br>
      <input type="file" name="file" required=""><br>
      <input name="submit" type="submit" value="Submit">
    </form>
  </body>
</html>

are there dictionaries in javascript like python?

Firefox 13+ provides an experimental implementation of the map object similar to the dict object in python. Specifications here.

It's only avaible in firefox, but it looks better than using attributes of a new Object(). Citation from the documentation :

  • An Object has a prototype, so there are default keys in the map. However, this can be bypassed using map = Object.create(null).
  • The keys of an Object are Strings, where they can be any value for a Map.
  • You can get the size of a Map easily while you have to manually keep track of size for an Object.

Shell script : How to cut part of a string

A perl-solution:

perl -nE 'say $1 if /id=(\d+)/' filename

MySQL dump by query

You could use --where option on mysqldump to produce an output that you are waiting for:

mysqldump -u root -p test t1 --where="1=1 limit 100" > arquivo.sql

At most 100 rows from test.t1 will be dumped from database table.

Cheers, WB

Run a Docker image as a container

To view a list of all images on your Docker host, run:

  $ docker images
   REPOSITORY          TAG           IMAGE ID            CREATED             SIZE
   apache_snapshot     latest        13037686eac3        22 seconds ago      249MB
   ubuntu              latest        00fd29ccc6f1        3 weeks ago         111MB

Now you can run the Docker image as a container in interactive mode:

   $ docker run -it apache_snapshot /bin/bash

OR if you don't have any images locally,Search Docker Hub for an image to download:

    $ docker search ubuntu
    NAME                            DESCRIPTION             STARS  OFFICIAL  AUTOMATED
    ubuntu                          Ubuntu is a Debian...   6759   [OK]       
    dorowu/ubuntu-desktop-lxde-vnc  Ubuntu with openss...   141              [OK]
    rastasheep/ubuntu-sshd          Dockerized SSH ser...   114              [OK]
    ansible/ubuntu14.04-ansible     Ubuntu 14.04 LTS w...   88               [OK]
    ubuntu-upstart                  Upstart is an even...   80     [OK]

Pull the Docker image from a repository with the docker pull command:

     $ docker pull ubuntu

Run the Docker image as a container:

     $ docker run -it ubuntu /bin/bash

HTML5 form required attribute. Set custom validation message?

Adapting Salar's answer to JSX and React, I noticed that React Select doesn't behave just like an <input/> field regarding validation. Apparently, several workarounds are needed to show only the custom message and to keep it from showing at inconvenient times.

I've raised an issue here, if it helps anything. Here is a CodeSandbox with a working example, and the most important code there is reproduced here:

Hello.js

import React, { Component } from "react";
import SelectValid from "./SelectValid";

export default class Hello extends Component {
  render() {
    return (
      <form>
        <SelectValid placeholder="this one is optional" />
        <SelectValid placeholder="this one is required" required />
        <input
          required
          defaultValue="foo"
          onChange={e => e.target.setCustomValidity("")}
          onInvalid={e => e.target.setCustomValidity("foo")}
        />
        <button>button</button>
      </form>
    );
  }
}

SelectValid.js

import React, { Component } from "react";
import Select from "react-select";
import "react-select/dist/react-select.css";

export default class SelectValid extends Component {
  render() {
    this.required = !this.props.required
      ? false
      : this.state && this.state.value ? false : true;
    let inputProps = undefined;
    let onInputChange = undefined;
    if (this.props.required) {
      inputProps = {
        onInvalid: e => e.target.setCustomValidity(this.required ? "foo" : "")
      };
      onInputChange = value => {
        this.selectComponent.input.input.setCustomValidity(
          value
            ? ""
            : this.required
              ? "foo"
              : this.selectComponent.props.value ? "" : "foo"
        );
        return value;
      };
    }
    return (
      <Select
        onChange={value => {
          this.required = !this.props.required ? false : value ? false : true;
          let state = this && this.state ? this.state : { value: null };
          state.value = value;
          this.setState(state);
          if (this.props.onChange) {
            this.props.onChange();
          }
        }}
        value={this && this.state ? this.state.value : null}
        options={[{ label: "yes", value: 1 }, { label: "no", value: 0 }]}
        placeholder={this.props.placeholder}
        required={this.required}
        clearable
        searchable
        inputProps={inputProps}
        ref={input => (this.selectComponent = input)}
        onInputChange={onInputChange}
      />
    );
  }
}

Path of currently executing powershell script

From Get-ScriptDirectory to the Rescue blog entry ...

function Get-ScriptDirectory
{
  $Invocation = (Get-Variable MyInvocation -Scope 1).Value
  Split-Path $Invocation.MyCommand.Path
}

How can I get customer details from an order in WooCommerce?

I did manage to figure it out:

$order_meta    = get_post_meta($order_id);
$email         = $order_meta["_shipping_email"][0] ?: $order_meta["_billing_email"][0];

I do know know for sure if the shipping email is part of the metadata, but if so I would rather have it than the billing email - at least for my purposes.

How can I change column types in Spark SQL's DataFrame?

df.select($"long_col".cast(IntegerType).as("int_col"))

Activate tabpage of TabControl

There are two properties in a TabControl control that manages which tab page is selected.

SelectedIndex which offer the possibility to select it by index (an integer starting from 0 to the number of tabs you have minus one).

SelectedTab which offer the possibility to selected the tab object itself to select.

Setting either of these property will change the currently displayed tab.

Alternatively you can also use the Select method. It comes in three flavour, one where you pass the index of the tab, another the TabPage object itself and the last one a string representing the tab's name.

How to use executables from a package installed locally in node_modules?

I've always used the same approach as @guneysus to solve this problem, which is creating a script in the package.json file and use it running npm run script-name.

However, in the recent months I've been using npx and I love it.

For example, I downloaded an Angular project and I didn't want to install the Angular CLI globally. So, with npx installed, instead of using the global angular cli command (if I had installed it) like this:

ng serve

I can do this from the console:

npx ng serve

Here's an article I wrote about NPX and that goes deeper into it.

ADB not recognising Nexus 4 under Windows 7

How to do it on Windows 8 (I think, it will work for Windows 7 too)

  1. Open Android SDK Manager and delete Google Usb Driver
  2. Open Control Panel -> Devices Manager -> Find your Nexus -> right click -> delete device
  3. Unplug your device
  4. Open Android SDK Manager and install Google Usb Driver
  5. Connect your device
  6. Open Control Panel -> Devices Manager -> Find your Nexus -> right click -> update drivers -> Manual update -> open android-sdk folder (enable checkbox for subfolders) -> install driver from Google Inc
  7. adb kill-server; adb start-server; adb devices should show your nexus

Do not forget, that Android 4.2 now want you to submit RSA key from your computer, look at your device screen.

To enable developers options on Android 4.2: Open Settings -> About phone -> Tap on Build Number 7 times.

Escape double quote character in XML

New, improved answer to an old, frequently asked question...

When to escape double quote in XML

Double quote (") may appear without escaping:

  • In XML textual content:

    <NoEscapeNeeded>He said, "Don't quote me."</NoEscapeNeeded>
    
  • In XML attributes delimited by single quotes ('):

    <NoEscapeNeeded name='Pete "Maverick" Mitchell'/>
    

    Note: switching to single quotes (') also requires no escaping:

    <NoEscapeNeeded name="Pete 'Maverick' Mitchell"/>
    

Double quote (") must be escaped:

  • In XML attributes delimited by double quotes:

    <EscapeNeeded name="Pete &quot;Maverick&quot; Mitchell"/>
    

Bottom line

Double quote (") must be escaped as &quot; in XML only in very limited contexts.

@UniqueConstraint and @Column(unique = true) in hibernate annotation

As said before, @Column(unique = true) is a shortcut to UniqueConstraint when it is only a single field.

From the example you gave, there is a huge difference between both.

@Column(unique = true)
@ManyToOne(optional = false, fetch = FetchType.EAGER)
private ProductSerialMask mask;

@Column(unique = true)
@ManyToOne(optional = false, fetch = FetchType.EAGER)
private Group group;

This code implies that both mask and group have to be unique, but separately. That means that if, for example, you have a record with a mask.id = 1 and tries to insert another record with mask.id = 1, you'll get an error, because that column should have unique values. The same aplies for group.

On the other hand,

@Table(
   name = "product_serial_group_mask", 
   uniqueConstraints = {@UniqueConstraint(columnNames = {"mask", "group"})}
)

Implies that the values of mask + group combined should be unique. That means you can have, for example, a record with mask.id = 1 and group.id = 1, and if you try to insert another record with mask.id = 1 and group.id = 2, it'll be inserted successfully, whereas in the first case it wouldn't.

If you'd like to have both mask and group to be unique separately and to that at class level, you'd have to write the code as following:

@Table(
        name = "product_serial_group_mask",
        uniqueConstraints = {
                @UniqueConstraint(columnNames = "mask"),
                @UniqueConstraint(columnNames = "group")
        }
)

This has the same effect as the first code block.

Postgres user does not exist?

OS X tends to prefix the system account names with "_"; you don't say what version of OS X you're using, but at least in 10.8 and 10.9 the _postgres user exists in a default install. Note that you won't be able to su to this account (except as root), since it doesn't have a password. sudo -u _postgres, on the other hand, should work fine.

How do I find what Java version Tomcat6 is using?

For Windows, launch cmd prompt and route to the path(usually bin) where you have your tomcat startup script.

C:\opt\isv\tomcat-7.0\grid\bin>version
Using CATALINA_BASE:   "C:\opt\isv\tomcat-7.0\grid"
Using CATALINA_HOME:   "C:\opt\isv\tomcat-7.0\grid"
Using CATALINA_TMPDIR: "C:\opt\isv\tomcat-7.0\grid\temp"
Using JRE_HOME:        "C:\opt\isv\devtools\jdk1.8.0_45"
Using CLASSPATH:       "C:\opt\isv\tomcat-7.0\grid\bin\bootstrap.jar;C:\opt\isv\tomcat-7.0\grid\bin\tomcat-juli.jar"
Server version: Apache Tomcat/7.0.55
Server built:   Jul 18 2014 05:34:04
Server number:  7.0.55.0
OS Name:        Windows 7
OS Version:     6.1
Architecture:   x86
JVM Version:    1.8.0_45-b15
JVM Vendor:     Oracle Corporation
C:\opt\isv\tomcat-7.0\grid\bin>

Interview question: Check if one string is a rotation of other string

First make sure s1 and s2 are of the same length. Then check to see if s2 is a substring of s1 concatenated with s1:

algorithm checkRotation(string s1, string s2) 
  if( len(s1) != len(s2))
    return false
  if( substring(s2,concat(s1,s1))
    return true
  return false
end

In Java:

boolean isRotation(String s1,String s2) {
    return (s1.length() == s2.length()) && ((s1+s1).indexOf(s2) != -1);
}

How to update a pull request from forked repo?

You have done it correctly. The pull request will automatically update. The process is:

  1. Open pull request
  2. Commit changes based on feedback in your local repo
  3. Push to the relevant branch of your fork

The pull request will automatically add the new commits at the bottom of the pull request discussion (ie, it's already there, scroll down!)

sql server invalid object name - but tables are listed in SSMS tables list

Don't forget to create your migrations after writing the models

Set windows environment variables with a batch file

@ECHO OFF

:: %HOMEDRIVE% = C:
:: %HOMEPATH% = \Users\Ruben
:: %system32% ??
:: No spaces in paths
:: Program Files > ProgramFiles
:: cls = clear screen
:: CMD reads the system environment variables when it starts. To re-read those variables you need to restart CMD
:: Use console 2 http://sourceforge.net/projects/console/


:: Assign all Path variables
SET PHP="%HOMEDRIVE%\wamp\bin\php\php5.4.16"
SET SYSTEM32=";%HOMEDRIVE%\Windows\System32"
SET ANT=";%HOMEDRIVE%%HOMEPATH%\Downloads\apache-ant-1.9.0-bin\apache-ant-1.9.0\bin"
SET GRADLE=";%HOMEDRIVE%\tools\gradle-1.6\bin;"
SET ADT=";%HOMEDRIVE%\tools\adt-bundle-windows-x86-20130219\eclipse\jre\bin"
SET ADTTOOLS=";%HOMEDRIVE%\tools\adt-bundle-windows-x86-20130219\sdk\tools"
SET ADTP=";%HOMEDRIVE%\tools\adt-bundle-windows-x86-20130219\sdk\platform-tools"
SET YII=";%HOMEDRIVE%\wamp\www\yii\framework"
SET NODEJS=";%HOMEDRIVE%\ProgramFiles\nodejs"
SET CURL=";%HOMEDRIVE%\tools\curl_734_0_ssl"
SET COMPOSER=";%HOMEDRIVE%\ProgramData\ComposerSetup\bin"
SET GIT=";%HOMEDRIVE%\Program Files\Git\cmd"

:: Set Path variable
setx PATH "%PHP%%SYSTEM32%%NODEJS%%COMPOSER%%YII%%GIT%" /m

:: Set Java variable
setx JAVA_HOME "%HOMEDRIVE%\ProgramFiles\Java\jdk1.7.0_21" /m

PAUSE

Returning JSON object from an ASP.NET page

With ASP.NET Web Pages you can do this on a single page as a basic GET example (the simplest possible thing that can work.

var json = Json.Encode(new {
    orientation = Cache["orientation"],
    alerted = Cache["alerted"] as bool?,
    since = Cache["since"] as DateTime?
});
Response.Write(json);

String's Maximum length in Java - calling length() method

I have a 2010 iMac with 8GB of RAM, running Eclipse Neon.2 Release (4.6.2) with Java 1.8.0_25. With the VM argument -Xmx6g, I ran the following code:

StringBuilder sb = new StringBuilder();
for (int i = 0; i < Integer.MAX_VALUE; i++) {
    try {
        sb.append('a');
    } catch (Throwable e) {
        System.out.println(i);
        break;
    }
}
System.out.println(sb.toString().length());

This prints:

Requested array size exceeds VM limit
1207959550

So, it seems that the max array size is ~1,207,959,549. Then I realized that we don't actually care if Java runs out of memory: we're just looking for the maximum array size (which seems to be a constant defined somewhere). So:

for (int i = 0; i < 1_000; i++) {
    try {
        char[] array = new char[Integer.MAX_VALUE - i];
        Arrays.fill(array, 'a');
        String string = new String(array);
        System.out.println(string.length());
    } catch (Throwable e) {
        System.out.println(e.getMessage());
        System.out.println("Last: " + (Integer.MAX_VALUE - i));
        System.out.println("Last: " + i);
    }
}

Which prints:

Requested array size exceeds VM limit
Last: 2147483647
Last: 0
Requested array size exceeds VM limit
Last: 2147483646
Last: 1
Java heap space
Last: 2147483645
Last: 2

So, it seems the max is Integer.MAX_VALUE - 2, or (2^31) - 3

P.S. I'm not sure why my StringBuilder maxed out at 1207959550 while my char[] maxed out at (2^31)-3. It seems that AbstractStringBuilder doubles the size of its internal char[] to grow it, so that probably causes the issue.

Python: pandas merge multiple dataframes

Thank you for your help @jezrael, @zipa and @everestial007, both answers are what I need. If I wanted to make a recursive, this would also work as intended:

def mergefiles(dfs=[], on=''):
    """Merge a list of files based on one column"""
    if len(dfs) == 1:
         return "List only have one element."

    elif len(dfs) == 2:
        df1 = dfs[0]
        df2 = dfs[1]
        df = df1.merge(df2, on=on)
        return df

    # Merge the first and second datafranes into new dataframe
    df1 = dfs[0]
    df2 = dfs[1]
    df = dfs[0].merge(dfs[1], on=on)

    # Create new list with merged dataframe
    dfl = []
    dfl.append(df)

    # Join lists
    dfl = dfl + dfs[2:] 
    dfm = mergefiles(dfl, on)
    return dfm

How does DateTime.Now.Ticks exactly work?

You can get the milliseconds since 1/1/1970 using such code:

private static DateTime JanFirst1970 = new DateTime(1970, 1, 1);
public static long getTime()
{
    return (long)((DateTime.Now.ToUniversalTime() - JanFirst1970).TotalMilliseconds + 0.5);
}

What does the error "JSX element type '...' does not have any construct or call signatures" mean?

When I'm converting from JSX to TSX and we keep some libraries as js/jsx and convert others to ts/tsx I almost always forget to change the js/jsx import statements in the TSX\TS files from

import * as ComponentName from "ComponentName";

to

import ComponentName from "ComponentName";

If calling an old JSX (React.createClass) style component from TSX, then use

var ComponentName = require("ComponentName")

Validate email with a regex in jQuery

This regex can help you to check your email-address according to all the criteria which gmail.com used.

var re = /^\w+([-+.'][^\s]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$/;

var emailFormat = re.test($("#email").val()); // This return result in Boolean type

if (emailFormat) {}

How do I remove/delete a virtualenv?

1. Remove the Python environment

There is no command to remove a virtualenv so you need to do that by hand, you will need to deactivate if you have it on and remove the folder:

deactivate
rm -rf <env name>

2. Create an env. with another Python version

When you create an environment the python uses the current version by default, so if you want another one you will need to specify at the moment you are creating it. To make and env. with Python 3.7 called MyEnv just type:

python3.7 -m venv MyEnv

Now to make with Python 2.X use virtualenv instead of venv:

python2.7 -m virtualenv MyEnv

3. List all Python versions on my machine

If any of the previous lines of code didn't worked you probably don't have the specific version installed. First list all your versions with:

ls -ls /usr/bin/python*

If you didn't find it, install Python 3.7 using apt-get:

sudo apt-get install python3.7

And with yum:

sudo yum install python3

4. Best practice: upgrade you pip (weekly)

pip install --upgrade pip

How to prevent form from being submitted?

Attach an event listener to the form using .addEventListener() and then call the .preventDefault() method on event:

_x000D_
_x000D_
const element = document.querySelector('form');_x000D_
element.addEventListener('submit', event => {_x000D_
  event.preventDefault();_x000D_
  // actual logic, e.g. validate the form_x000D_
  console.log('Form submission cancelled.');_x000D_
});
_x000D_
<form>_x000D_
  <button type="submit">Submit</button>_x000D_
</form>
_x000D_
_x000D_
_x000D_

I think it's a better solution than defining a submit event handler inline with the onsubmit attribute because it separates webpage logic and structure. It's much easier to maintain a project where logic is separated from HTML. See: Unobtrusive JavaScript.

Using the .onsubmit property of the form DOM object is not a good idea because it prevents you from attaching multiple submit callbacks to one element. See addEventListener vs onclick .

Can the Android drawable directory contain subdirectories?

This is not perfect methods. You have to implement same way which is display here.

You can also call the image under the folder through the code you can use

Resources res = getResources();
Drawable shape = res. getDrawable(R.drawable.gradient_box);

TextView tv = (TextView)findViewByID(R.id.textview);
tv.setBackground(shape);

Importing Excel files into R, xlsx or xls

I have tried very hard on all the answers above. However, they did not actually help because I used a mac. The rio library has this import function which can basically import any type of data file into Rstudio, even those file using languages other than English!

Try codes below:

    library(rio)
    AB <- import("C:/AB_DNA_Tag_Numbers.xlsx")
    AB <- AB[,1]

Hope this help. For more detailed reference: https://cran.r-project.org/web/packages/rio/vignettes/rio.html

How to call codeigniter controller function from view

Try this one.

Add this code in Your View file

$CI     = & get_instance();
$result = $CI->FindFurnishName($pera);

Add code in Your controller File

public function FindFurnishName($furnish_filter)

{

$FindFurnishName        = $this->index_modal->FindFurnishName($furnish_filter);  
$FindFurnishName_val    = '';
foreach($FindFurnishName as $AllRea)
{
    $FindFurnishName_val  .= ",".$AllRea->name;
}
return ltrim($FindFurnishName_val,',');

}

where

  1. FindFurnishName is name of function which is define in Your Controller.
  2. $pera is a option ( as your need).

How can I set / change DNS using the command-prompt at windows 8

None of the answers are working for me on Windows 10, so here's what I use:

@echo off

set DNS1=8.8.8.8
set DNS2=8.8.4.4
set INTERFACE=Ethernet

netsh int ipv4 set dns name="%INTERFACE%" static %DNS1% primary validate=no
netsh int ipv4 add dns name="%INTERFACE%" %DNS2% index=2

ipconfig /flushdns

pause

This uses Google DNS. You can get interface name with the command netsh int show interface

Spring Boot Multiple Datasource

I think you can find it usefull

http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#howto-two-datasources

It shows how to define multiple datasources & assign one of them as primary.

Here is a rather full example, also contains distributes transactions - if you need it.

http://fabiomaffioletti.me/blog/2014/04/15/distributed-transactions-multiple-databases-spring-boot-spring-data-jpa-atomikos/

What you need is to create 2 configuration classes, separate the model/repository packages etc to make the config easy.

Also, in above example, it creates the data sources manually. You can avoid this using the method on spring doc, with @ConfigurationProperties annotation. Here is an example of this:

http://xantorohara.blogspot.com.tr/2013/11/spring-boot-jdbc-with-multiple.html

Hope these helps.

Center a DIV horizontally and vertically

The legitimate way to do that irrespective of size of the div for any browser size is :

   div{
    margin:auto;
    height: 200px;
    width: 200px;
    position:fixed;
    top:0;
    bottom:0;
    left:0;
    right:0;
    background:red;
   }

Live Code

jquery to change style attribute of a div class

Try with

$('.handle').css({'left': '300px'});

Instead of

$('.handle').css({'style':'left: 300px'})

How to enable external request in IIS Express?

A good resource is Working with SSL at Development Time is easier with IISExpress by Scott Hanselman.

What you're after is the section Getting IIS Express to serve externally over Port 80

Android Crop Center of Bitmap

public static Bitmap resizeAndCropCenter(Bitmap bitmap, int size, boolean recycle) {
    int w = bitmap.getWidth();
    int h = bitmap.getHeight();
    if (w == size && h == size) return bitmap;
    // scale the image so that the shorter side equals to the target;
    // the longer side will be center-cropped.
    float scale = (float) size / Math.min(w,  h);
    Bitmap target = Bitmap.createBitmap(size, size, getConfig(bitmap));
    int width = Math.round(scale * bitmap.getWidth());
    int height = Math.round(scale * bitmap.getHeight());
    Canvas canvas = new Canvas(target);
    canvas.translate((size - width) / 2f, (size - height) / 2f);
    canvas.scale(scale, scale);
    Paint paint = new Paint(Paint.FILTER_BITMAP_FLAG | Paint.DITHER_FLAG);
    canvas.drawBitmap(bitmap, 0, 0, paint);
    if (recycle) bitmap.recycle();
    return target;
}

private static Bitmap.Config getConfig(Bitmap bitmap) {
    Bitmap.Config config = bitmap.getConfig();
    if (config == null) {
        config = Bitmap.Config.ARGB_8888;
    }
    return config;
}

Turn off deprecated errors in PHP 5.3

I tend to use this method

$errorlevel=error_reporting();
$errorlevel=error_reporting($errorlevel & ~E_DEPRECATED);

In this way I do not turn off accidentally something I need

Utilizing multi core for tar+gzip/bzip compression/decompression

Common approach

There is option for tar program:

-I, --use-compress-program PROG
      filter through PROG (must accept -d)

You can use multithread version of archiver or compressor utility.

Most popular multithread archivers are pigz (instead of gzip) and pbzip2 (instead of bzip2). For instance:

$ tar -I pbzip2 -cf OUTPUT_FILE.tar.bz2 paths_to_archive
$ tar --use-compress-program=pigz -cf OUTPUT_FILE.tar.gz paths_to_archive

Archiver must accept -d. If your replacement utility hasn't this parameter and/or you need specify additional parameters, then use pipes (add parameters if necessary):

$ tar cf - paths_to_archive | pbzip2 > OUTPUT_FILE.tar.gz
$ tar cf - paths_to_archive | pigz > OUTPUT_FILE.tar.gz

Input and output of singlethread and multithread are compatible. You can compress using multithread version and decompress using singlethread version and vice versa.

p7zip

For p7zip for compression you need a small shell script like the following:

#!/bin/sh
case $1 in
  -d) 7za -txz -si -so e;;
   *) 7za -txz -si -so a .;;
esac 2>/dev/null

Save it as 7zhelper.sh. Here the example of usage:

$ tar -I 7zhelper.sh -cf OUTPUT_FILE.tar.7z paths_to_archive
$ tar -I 7zhelper.sh -xf OUTPUT_FILE.tar.7z

xz

Regarding multithreaded XZ support. If you are running version 5.2.0 or above of XZ Utils, you can utilize multiple cores for compression by setting -T or --threads to an appropriate value via the environmental variable XZ_DEFAULTS (e.g. XZ_DEFAULTS="-T 0").

This is a fragment of man for 5.1.0alpha version:

Multithreaded compression and decompression are not implemented yet, so this option has no effect for now.

However this will not work for decompression of files that haven't also been compressed with threading enabled. From man for version 5.2.2:

Threaded decompression hasn't been implemented yet. It will only work on files that contain multiple blocks with size information in block headers. All files compressed in multi-threaded mode meet this condition, but files compressed in single-threaded mode don't even if --block-size=size is used.

Recompiling with replacement

If you build tar from sources, then you can recompile with parameters

--with-gzip=pigz
--with-bzip2=lbzip2
--with-lzip=plzip

After recompiling tar with these options you can check the output of tar's help:

$ tar --help | grep "lbzip2\|plzip\|pigz"
  -j, --bzip2                filter the archive through lbzip2
      --lzip                 filter the archive through plzip
  -z, --gzip, --gunzip, --ungzip   filter the archive through pigz

UIViewController viewDidLoad vs. viewWillAppear: What is the proper division of labor?

Initially used only ViewDidLoad with tableView. On testing with loss of Wifi, by setting device to airplane mode, realized that the table did not refresh with return of Wifi. In fact, there appears to be no way to refresh tableView on the device even by hitting the home button with background mode set to YES in -Info.plist.

My solution:

-(void) viewWillAppear: (BOOL) animated { [self.tableView reloadData];}

Get first line of a shell command's output

I would use:

awk 'FNR <= 1' file_*.txt

As @Kusalananda points out there are many ways to capture the first line in command line but using the head -n 1 may not be the best option when using wildcards since it will print additional info. Changing 'FNR == i' to 'FNR <= i' allows to obtain the first i lines.

For example, if you have n files named file_1.txt, ... file_n.txt:

awk 'FNR <= 1' file_*.txt

hello
...
bye

But with head wildcards print the name of the file:

head -1 file_*.txt

==> file_1.csv <==
hello
...
==> file_n.csv <==
bye

Calculating the sum of two variables in a batch script

You can solve any equation including adding with this code:

@echo off

title Richie's Calculator 3.0

:main

echo Welcome to Richie's Calculator 3.0

echo Press any key to begin calculating...

pause>nul

echo Enter An Equation

echo Example: 1+1

set /p 

set /a sum=%equation%

echo.

echo The Answer Is:

echo %sum%

echo.

echo Press any key to return to the main menu

pause>nul

cls

goto main

Split a large dataframe into a list of data frames based on common value in column

You can just as easily access each element in the list using e.g. path[[1]]. You can't put a set of matrices into an atomic vector and access each element. A matrix is an atomic vector with dimension attributes. I would use the list structure returned by split, it's what it was designed for. Each list element can hold data of different types and sizes so it's very versatile and you can use *apply functions to further operate on each element in the list. Example below.

#  For reproducibile data
set.seed(1)

#  Make some data
userid <- rep(1:2,times=4)
data1 <- replicate(8 , paste( sample(letters , 3 ) , collapse = "" ) )
data2 <- sample(10,8)
df <- data.frame( userid , data1 , data2 )

#  Split on userid
out <- split( df , f = df$userid )
#$`1`
#  userid data1 data2
#1      1   gjn     3
#3      1   yqp     1
#5      1   rjs     6
#7      1   jtw     5

#$`2`
#  userid data1 data2
#2      2   xfv     4
#4      2   bfe    10
#6      2   mrx     2
#8      2   fqd     9

Access each element using the [[ operator like this:

out[[1]]
#  userid data1 data2
#1      1   gjn     3
#3      1   yqp     1
#5      1   rjs     6
#7      1   jtw     5

Or use an *apply function to do further operations on each list element. For instance, to take the mean of the data2 column you could use sapply like this:

sapply( out , function(x) mean( x$data2 ) )
#   1    2 
#3.75 6.25 

Get only specific attributes with from Laravel Collection

You can do this using a combination of existing Collection methods. It may be a little hard to follow at first, but it should be easy enough to break down.

// get your main collection with all the attributes...
$users = Users::get();

// build your second collection with a subset of attributes. this new
// collection will be a collection of plain arrays, not Users models.
$subset = $users->map(function ($user) {
    return collect($user->toArray())
        ->only(['id', 'name', 'email'])
        ->all();
});

Explanation

First, the map() method basically just iterates through the Collection, and passes each item in the Collection to the passed in callback. The value returned from each call of the callback builds the new Collection generated by the map() method.

collect($user->toArray()) is just building a new, temporary Collection out of the Users attributes.

->only(['id', 'name', 'email']) reduces the temporary Collection down to only those attributes specified.

->all() turns the temporary Collection back into a plain array.

Put it all together and you get "For each user in the users collection, return an array of just the id, name, and email attributes."


Laravel 5.5 update

Laravel 5.5 added an only method on the Model, which basically does the same thing as the collect($user->toArray())->only([...])->all(), so this can be slightly simplified in 5.5+ to:

// get your main collection with all the attributes...
$users = Users::get();

// build your second collection with a subset of attributes. this new
// collection will be a collection of plain arrays, not Users models.
$subset = $users->map(function ($user) {
    return $user->only(['id', 'name', 'email']);
});

If you combine this with the "higher order messaging" for collections introduced in Laravel 5.4, it can be simplified even further:

// get your main collection with all the attributes...
$users = Users::get();

// build your second collection with a subset of attributes. this new
// collection will be a collection of plain arrays, not Users models.
$subset = $users->map->only(['id', 'name', 'email']);

Not equal to != and !== in PHP

$a !== $b TRUE if $a is not equal to $b, or they are not of the same type

Please Refer to http://php.net/manual/en/language.operators.comparison.php

Call a PHP function after onClick HTML event

There are two ways. the first is to completely refresh the page using typical form submission

//your_page.php

<?php 

$saveSuccess = null;
$saveMessage = null;

if($_SERVER['REQUEST_METHOD'] == 'POST') {
  // if form has been posted process data

  // you dont need the addContact function you jsut need to put it in a new array
  // and it doesnt make sense in this context so jsut do it here
  // then used json_decode and json_decode to read/save your json in
  // saveContact()
  $data = array(
    'fullname' = $_POST['fullname'],
    'email' => $_POST['email'],
    'phone' => $_POST['phone']
  );

  // always return true if you save the contact data ok or false if it fails
  if(($saveSuccess = saveContact($data)) {
     $saveMessage = 'Your submission has been saved!';     
  } else {
     $saveMessage = 'There was a problem saving your submission.';
  } 
}
?>

<!-- your other html -->

<?php if($saveSuccess !== null): ?>
   <p class="flash_message"><?php echo $saveMessage ?></p>
<?php endif; ?>

<form action="your_page.php" method="post">
    <fieldset>
        <legend>Add New Contact</legend>
        <input type="text" name="fullname" placeholder="First name and last name" required /> <br />
        <input type="email" name="email" placeholder="[email protected]" required /> <br />
        <input type="text" name="phone" placeholder="Personal phone number: mobile, home phone etc." required /> <br />
        <input type="submit" name="submit" class="button" value="Add Contact" onClick="" />
        <input type="button" name="cancel" class="button" value="Reset" />
    </fieldset>
</form>

<!-- the rest of your HTML -->

The second way would be to use AJAX. to do that youll want to completely seprate the form processing into a separate file:

// process.php

$response = array();

if($_SERVER['REQUEST_METHOD'] == 'POST') {
  // if form has been posted process data

  // you dont need the addContact function you jsut need to put it in a new array
  // and it doesnt make sense in this context so jsut do it here
  // then used json_decode and json_decode to read/save your json in
  // saveContact()
  $data = array(
    'fullname' => $_POST['fullname'],
    'email' => $_POST['email'],
    'phone' => $_POST['phone']
  );

  // always return true if you save the contact data ok or false if it fails
  $response['status'] = saveContact($data) ? 'success' : 'error';
  $response['message'] = $response['status']
      ? 'Your submission has been saved!'
      : 'There was a problem saving your submission.';

  header('Content-type: application/json');
  echo json_encode($response);
  exit;
}
?>

And then in your html/js

<form id="add_contact" action="process.php" method="post">
        <fieldset>
            <legend>Add New Contact</legend>
            <input type="text" name="fullname" placeholder="First name and last name" required /> <br />
            <input type="email" name="email" placeholder="[email protected]" required /> <br />
            <input type="text" name="phone" placeholder="Personal phone number: mobile, home phone etc." required /> <br />
            <input id="add_contact_submit" type="submit" name="submit" class="button" value="Add Contact" onClick="" />
            <input type="button" name="cancel" class="button" value="Reset" />
        </fieldset>
    </form>
    <script type="text/javascript">
     $(function(){
         $('#add_contact_submit').click(function(e){
            e.preventDefault();  
            $form = $(this).closest('form');

            // if you need to then wrap this ajax call in conditional logic

            $.ajax({
              url: $form.attr('action'),
              type: $form.attr('method'),
              dataType: 'json',
              success: function(responseJson) {
                 $form.before("<p>"+responseJson.message+"</p>");
              },
              error: function() {
                 $form.before("<p>There was an error processing your request.</p>");
              }
            });
         });         
     });
    </script>

How do I list loaded plugins in Vim?

:help local-additions

Lists local plugins added.

Ansible: Store command's stdout in new variable?

There's no need to set a fact.

    - shell: cat "hello"
      register: cat_contents

    - shell: echo "I cat hello"
      when: cat_contents.stdout == "hello"

How do I check if a type is a subtype OR the type of an object?

I'm posting this answer with the hope of someone sharing with me if and why it would be a bad idea. In my application, I have a property of Type that I want to check to be sure it is typeof(A) or typeof(B), where B is any class derived from A. So my code:

public class A
{
}

public class B : A
{
}

public class MyClass
{
    private Type _helperType;
    public Type HelperType
    {
        get { return _helperType; }
        set 
        {
            var testInstance = (A)Activator.CreateInstance(value);
            if (testInstance==null)
                throw new InvalidCastException("HelperType must be derived from A");
            _helperType = value;
        }
    }
}

I feel like I might be a bit naive here so any feedback would be welcome.

Simple http post example in Objective-C?

Here i'm adding sample code for http post print response and parsing as JSON if possible, it will handle everything async so your GUI will be refreshing just fine and will not freeze at all - which is important to notice.

//POST DATA
NSString *theBody = [NSString stringWithFormat:@"parameter=%@",YOUR_VAR_HERE];
NSData *bodyData = [theBody dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
//URL CONFIG
NSString *serverURL = @"https://your-website-here.com";
NSString *downloadUrl = [NSString stringWithFormat:@"%@/your-friendly-url-here/json",serverURL];
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString: downloadUrl]];
//POST DATA SETUP
[request setHTTPMethod:@"POST"];
[request setHTTPBody:bodyData];
//DEBUG MESSAGE
NSLog(@"Trying to call ws %@",downloadUrl);
//EXEC CALL
[NSURLConnection sendAsynchronousRequest:request queue:[NSOperationQueue currentQueue] completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
    if (error) {
        NSLog(@"Download Error:%@",error.description);
    }
    if (data) {

        //
        // THIS CODE IS FOR PRINTING THE RESPONSE
        //
        NSString *returnString = [[NSString alloc] initWithData:data encoding: NSUTF8StringEncoding];
        NSLog(@"Response:%@",returnString);

        //PARSE JSON RESPONSE
        NSDictionary *json_response = [NSJSONSerialization JSONObjectWithData:data
                                                                      options:0
                                                                        error:NULL];

        if ( json_response ) {
            if ( [json_response isKindOfClass:[NSDictionary class]] ) {
                // do dictionary things
                for ( NSString *key in [json_response allKeys] ) {
                    NSLog(@"%@: %@", key, json_response[key]);
                }
            }
            else if ( [json_response isKindOfClass:[NSArray class]] ) {
                NSLog(@"%@",json_response);
            }
        }
        else {
            NSLog(@"Error serializing JSON: %@", error);
            NSLog(@"RAW RESPONSE: %@",data);
            NSString *returnString2 = [[NSString alloc] initWithData:data encoding: NSUTF8StringEncoding];
            NSLog(@"Response:%@",returnString2);
        }
    }
}];

Hope this helps!

Excel: the Incredible Shrinking and Expanding Controls

Some of these problems may be due to controls resizing themselves when populated. I tend to the turn the IntegralHeight property of controls such as list boxes from True (default) to False to prevent automated resizing of the control height at runtime.

Node.js - Maximum call stack size exceeded

I had a similar issue as this. I had an issue with using multiple Array.map()'s in a row (around 8 maps at once) and was getting a maximum_call_stack_exceeded error. I solved this by changing the map's into 'for' loops

So if you are using alot of map calls, changing them to for loops may fix the problem

Edit

Just for clarity and probably-not-needed-but-good-to-know-info, using .map() causes the array to be prepped (resolving getters , etc) and the callback to be cached, and also internally keeps an index of the array (so the callback is provided with the correct index/value). This stacks with each nested call, and caution is advised when not nested as well, as the next .map() could be called before the first array is garbage collected (if at all).

Take this example:

var cb = *some callback function*
var arr1 , arr2 , arr3 = [*some large data set]
arr1.map(v => {
    *do something
})
cb(arr1)
arr2.map(v => {
    *do something // even though v is overwritten, and the first array
                  // has been passed through, it is still in memory
                  // because of the cached calls to the callback function
}) 

If we change this to:

for(var|let|const v in|of arr1) {
    *do something
}
cb(arr1)
for(var|let|const v in|of arr2) {
    *do something  // Here there is not callback function to 
                   // store a reference for, and the array has 
                   // already been passed of (gone out of scope)
                   // so the garbage collector has an opportunity
                   // to remove the array if it runs low on memory
}

I hope this makes some sense (I don't have the best way with words) and helps a few to prevent the head scratching I went through

If anyone is interested, here is also a performance test comparing map and for loops (not my work).

https://github.com/dg92/Performance-Analysis-JS

For loops are usually better than map, but not reduce, filter, or find

Pass multiple parameters in Html.BeginForm MVC

Another option I like, which can be generalized once I start seeing the code not conform to DRY, is to use one controller that redirects to another controller.

public ActionResult ClientIdSearch(int cid)
{
  var action = String.Format("Details/{0}", cid);

  return RedirectToAction(action, "Accounts");
}

I find this allows me to apply my logic in one location and re-use it without have to sprinkle JavaScript in the views to handle this. And, as I mentioned I can then refactor for re-use as I see this getting abused.

Jquery date picker z-index issue

worked for me

.hasDatepicker {
    position: relative;
    z-index: 9999;
}

regular expression for anything but an empty string

I think [ ]{4} might work in the example where you need to detect 4 spaces. Same with the rest: [ ]{1}, [ ]{2} and [ ]{3}. If you want to detect an empty string in general, ^[ ]*$ will do.

Prime numbers between 1 to 100 in C Programming Language

#include <stdio.h>
#include <conio.h>
int main()
{
    int i,j;
    int b=0;
    for (i=2;i<=100;i++){
        for (j=2;j<=i;j++){
            if (i%j==0){
                break;
            }
        }
        if (i==j)
            print f("\n%d",j);
    }
    getch ();
}

How to rollback just one step using rake db:migrate

For starters

rake db:rollback will get you back one step

then

rake db:rollback STEP=n

Will roll you back n migrations where n is the number of recent migrations you want to rollback.

More references here.

How to get the Enum Index value in C#

Use a cast:

public enum MyEnum : int    {
    A = 0,
    B = 1,
    AB = 2,
}


int val = (int)MyEnum.A;

CORS - How do 'preflight' an httprequest?

During the preflight request, you should see the following two headers: Access-Control-Request-Method and Access-Control-Request-Headers. These request headers are asking the server for permissions to make the actual request. Your preflight response needs to acknowledge these headers in order for the actual request to work.

For example, suppose the browser makes a request with the following headers:

Origin: http://yourdomain.com
Access-Control-Request-Method: POST
Access-Control-Request-Headers: X-Custom-Header

Your server should then respond with the following headers:

Access-Control-Allow-Origin: http://yourdomain.com
Access-Control-Allow-Methods: GET, POST
Access-Control-Allow-Headers: X-Custom-Header

Pay special attention to the Access-Control-Allow-Headers response header. The value of this header should be the same headers in the Access-Control-Request-Headers request header, and it can not be '*'.

Once you send this response to the preflight request, the browser will make the actual request. You can learn more about CORS here: http://www.html5rocks.com/en/tutorials/cors/

ALTER COLUMN in sqlite

SQLite supports a limited subset of ALTER TABLE. The ALTER TABLE command in SQLite allows the user to rename a table or to add a new column to an existing table. It is not possible to rename a column, remove a column, or add or remove constraints from a table. But you can alter table column datatype or other property by the following steps.

  1. BEGIN TRANSACTION;
  2. CREATE TEMPORARY TABLE t1_backup(a,b);
  3. INSERT INTO t1_backup SELECT a,b FROM t1;
  4. DROP TABLE t1;
  5. CREATE TABLE t1(a,b);
  6. INSERT INTO t1 SELECT a,b FROM t1_backup;
  7. DROP TABLE t1_backup;
  8. COMMIT

For more detail you can refer the link.

Node.js check if path is file or directory

The following should tell you. From the docs:

fs.lstatSync(path_string).isDirectory() 

Objects returned from fs.stat() and fs.lstat() are of this type.

stats.isFile()
stats.isDirectory()
stats.isBlockDevice()
stats.isCharacterDevice()
stats.isSymbolicLink() (only valid with fs.lstat())
stats.isFIFO()
stats.isSocket()

NOTE:

The above solution will throw an Error if; for ex, the file or directory doesn't exist.

If you want a true or false approach, try fs.existsSync(dirPath) && fs.lstatSync(dirPath).isDirectory(); as mentioned by Joseph in the comments below.

How to set label size in Bootstrap

In Bootstrap 3 they do not have separate classes for different styles of labels.

http://getbootstrap.com/components/

However, you can customize bootstrap classes that way. In your css file

.lb-sm {
  font-size: 12px;
}

.lb-md {
  font-size: 16px;
}

.lb-lg {
  font-size: 20px;
}

Alternatively, you can use header tags to change the sizes. For example, here is a medium sized label and a small-sized label

_x000D_
_x000D_
<link href="http://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" rel="stylesheet"/>_x000D_
<h3>Example heading <span class="label label-default">New</span></h3>_x000D_
<h6>Example heading <span class="label label-default">New</span></h6>
_x000D_
_x000D_
_x000D_

They might add size classes for labels in future Bootstrap versions.

Embedding a media player in a website using HTML

<html>

<head>
  <H1>
      Automatically play music files on your website when a page loads
    </H1>
</head>

<body>
  <embed src="YourMusic.mp3" autostart="true" loop="true" width="2" height="0">
  </embed>
</body>

</html>

React - how to pass state to another component

Move all of your state and your handleClick function from Header to your MainWrapper component.

Then pass values as props to all components that need to share this functionality.

class MainWrapper extends React.Component {
    constructor() {
        super();
        this.state = {
            sidbarPushCollapsed: false,
            profileCollapsed: false
        };
        this.handleClick = this.handleClick.bind(this);
    }
    handleClick() {
        this.setState({
            sidbarPushCollapsed: !this.state.sidbarPushCollapsed,
            profileCollapsed: !this.state.profileCollapsed

        });
    }
    render() {
        return (
           //...
           <Header 
               handleClick={this.handleClick} 
               sidbarPushCollapsed={this.state.sidbarPushCollapsed}
               profileCollapsed={this.state.profileCollapsed} />
        );

Then in your Header's render() method, you'd use this.props:

<button type="button" id="sidbarPush" onClick={this.props.handleClick} profile={this.props.profileCollapsed}>

Split string with delimiters in C

Try use this.

char** strsplit(char* str, const char* delim){
    char** res = NULL;
    char*  part;
    int i = 0;

    char* aux = strdup(str);

    part = strdup(strtok(aux, delim));

    while(part){
        res = (char**)realloc(res, (i + 1) * sizeof(char*));
        *(res + i) = strdup(part);

        part = strdup(strtok(NULL, delim));
        i++;
    }

    res = (char**)realloc(res, i * sizeof(char*));
    *(res + i) = NULL;

    return res;
}

How to process images of a video, frame by frame, in video streaming using OpenCV and Python

Use this:

import cv2
cap = cv2.VideoCapture('path to video file')
count = 0
while cap.isOpened():
    ret,frame = cap.read()
    cv2.imshow('window-name', frame)
    cv2.imwrite("frame%d.jpg" % count, frame)
    count = count + 1
    if cv2.waitKey(10) & 0xFF == ord('q'):
        break

cap.release()
cv2.destroyAllWindows() # destroy all opened windows

A server is already running. Check …/tmp/pids/server.pid. Exiting - rails

Issue can be solved using:

kill -9 $(more /home/..name/rprojects/railsapp/tmp/pids/server.pid)

Formatting a double to two decimal places

I would recomment the Fixed-Point ("F") format specifier (as mentioned by Ehsan). See the Standard Numeric Format Strings.

With this option you can even have a configurable number of decimal places:

public string ValueAsString(double value, int decimalPlaces)
{
    return value.ToString($"F{decimalPlaces}");
}

JQuery datepicker language

A quick Update, for the text "Today", the right names are:

todayText: 'Huidige', todayStatus: 'Bekijk de huidige maand',

Gerrit error when Change-Id in commit messages are missing

We solved this issue this morning by re-cloning repository and re-applying changes. This is the simplest way to re-sync your local copy with Gerrit. As always we created a backup first.

Although there are a number of other wildly complicated solutions, its often advantageous to take a simple approach to avoid making things worse.

How to embed images in email

Here is how to get the code for an embedded image without worrying about any files or base64 statements or mimes (it's still base64, but you don't have to do anything to get it). I originally posted this same answer in this thread, but it may be valuable to repeat it in this one, too.

To do this, you need Mozilla Thunderbird, you can fetch the html code for an image like this:

  1. Copy a bitmap to clipboard.
  2. Start a new email message.
  3. Paste the image. (don't save it as a draft!!!)
  4. Double-click on it to get to the image settings dialogue.
  5. Look for the "image location" property.
  6. Fetch the code and wrap it in an image tag, like this:

You should end up with a string of text something like this:

<img src="data:image/png;base64,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" alt="" height="211" width="213">

You can wrap this up into a string variable and place this absolutely anywhere that you would present an html email message - even in your email signatures. The advantage is that there are no attachments, and there are no links. (this code will display a lizard)

A picture is worth a thousand words: enter image description here

Incidentally, I did write a program to do all of this for you. It's called BaseImage, and it will create the image code as well as the html for you. Please don't consider this self-promotion; I'm just sharing a solution.

Excel Macro : How can I get the timestamp in "yyyy-MM-dd hh:mm:ss" format?

Copy and paste this format yyyy-mm-dd hh:MM:ss in format cells by clicking customs category under Type

Set a form's action attribute when submitting?

You can also set onSubmit attribute's value in form tag. You can set its value using Javascript.

Something like this:

<form id="whatever" name="whatever" onSubmit="return xyz();">
    Here is your entire form
    <input type="submit">
</form>;

<script type=text/javascript>
function xyz() {
  document.getElementById('whatever').action = 'whatever you want'
}
</script>

Remember that onSubmit has higher priority than action attribute. So whenever you specify onSubmit value, that operation will be performed first and then the form will move to action.

Create hyperlink to another sheet

In my implementation, the cell I was referencing could have been several options. I used the following format where 'ws' is the current worksheet being edited

For each ws in Activeworkbook.Worksheets
    For i…
       For j...
...
ws.Cells(i, j).Value = "=HYPERLINK(""#'" & SHEET-REF-VAR & "'!" & CELL-REF-VAR & """,""" & SHEET-REF-VAR & """)"

Java getHours(), getMinutes() and getSeconds()

Try this:

Calendar calendar = Calendar.getInstance();
calendar.setTime(yourdate);
int hours = calendar.get(Calendar.HOUR_OF_DAY);
int minutes = calendar.get(Calendar.MINUTE);
int seconds = calendar.get(Calendar.SECOND);

Edit:

hours, minutes, seconds

above will be the hours, minutes and seconds after converting yourdate to System Timezone!

How to return XML in ASP.NET?

I've found the proper way to return XML to a client in ASP.NET. I think if I point out the wrong ways, it will make the right way more understandable.

Incorrect:

Response.Write(doc.ToString());

Incorrect:

Response.Write(doc.InnerXml);

Incorrect:

Response.ContentType = "text/xml";
Response.ContentEncoding = System.Text.Encoding.UTF8;
doc.Save(Response.OutputStream);

Correct:

Response.ContentType = "text/xml"; //Must be 'text/xml'
Response.ContentEncoding = System.Text.Encoding.UTF8; //We'd like UTF-8
doc.Save(Response.Output); //Save to the text-writer
      //using the encoding of the text-writer
      //(which comes from response.contentEncoding)

Use a TextWriter

Do not use Response.OutputStream

Do use Response.Output

Both are streams, but Output is a TextWriter. When an XmlDocument saves itself to a TextWriter, it will use the encoding specified by that TextWriter. The XmlDocument will automatically change the xml declaration node to match the encoding used by the TextWriter. e.g. in this case the XML declaration node:

<?xml version="1.0" encoding="ISO-8859-1"?>

would become

<?xml version="1.0" encoding="UTF-8"?>

This is because the TextWriter has been set to UTF-8. (More on this in a moment). As the TextWriter is fed character data, it will encode it with the byte sequences appropriate for its set encoding.

Incorrect:

doc.Save(Response.OutputStream);

In this example the document is incorrectly saved to the OutputStream, which performs no encoding change, and may not match the response's content-encoding or the XML declaration node's specified encoding.

Correct

doc.Save(Response.Output);

The XML document is correctly saved to a TextWriter object, ensuring the encoding is properly handled.


Set Encoding

The encoding given to the client in the header:

Response.ContentEncoding = ...

must match the XML document's encoding:

<?xml version="1.0" encoding="..."?>

must match the actual encoding present in the byte sequences sent to the client. To make all three of these things agree, set the single line:

Response.ContentEncoding = System.Text.Encoding.UTF8;

When the encoding is set on the Response object, it sets the same encoding on the TextWriter. The encoding set of the TextWriter causes the XmlDocument to change the xml declaration:

<?xml version="1.0" encoding="UTF-8"?>

when the document is Saved:

doc.Save(someTextWriter);

Save to the response Output

You do not want to save the document to a binary stream, or write a string:

Incorrect:

doc.Save(Response.OutputStream);

Here the XML is incorrectly saved to a binary stream. The final byte encoding sequence won't match the XML declaration, or the web-server response's content-encoding.

Incorrect:

Response.Write(doc.ToString());
Response.Write(doc.InnerXml);

Here the XML is incorrectly converted to a string, which does not have an encoding. The XML declaration node is not updated to reflect the encoding of the response, and the response is not properly encoded to match the response's encoding. Also, storing the XML in an intermediate string wastes memory.

You don't want to save the XML to a string, or stuff the XML into a string and response.Write a string, because that:

- doesn't follow the encoding specified
- doesn't set the XML declaration node to match
- wastes memory

Do use doc.Save(Response.Output);

Do not use doc.Save(Response.OutputStream);

Do not use Response.Write(doc.ToString());

Do not use 'Response.Write(doc.InnerXml);`


Set the content-type

The Response's ContentType must be set to "text/xml". If not, the client will not know you are sending it XML.

Final Answer

Response.Clear(); //Optional: if we've sent anything before
Response.ContentType = "text/xml"; //Must be 'text/xml'
Response.ContentEncoding = System.Text.Encoding.UTF8; //We'd like UTF-8
doc.Save(Response.Output); //Save to the text-writer
    //using the encoding of the text-writer
    //(which comes from response.contentEncoding)
Response.End(); //Optional: will end processing

Complete Example

Rob Kennedy had the good point that I failed to include the start-to-finish example.

GetPatronInformation.ashx:

<%@ WebHandler Language="C#" Class="Handler" %>

using System;
using System.Web;
using System.Xml;
using System.IO;
using System.Data.Common;

//Why a "Handler" and not a full ASP.NET form?
//Because many people online critisized my original solution
//that involved the aspx (and cutting out all the HTML in the front file),
//noting the overhead of a full viewstate build-up/tear-down and processing,
//when it's not a web-form at all. (It's a pure processing.)

public class Handler : IHttpHandler
{
   public void ProcessRequest(HttpContext context)
   {
      //GetXmlToShow will look for parameters from the context
      XmlDocument doc = GetXmlToShow(context);

      //Don't forget to set a valid xml type.
      //If you leave the default "text/html", the browser will refuse to display it correctly
      context.Response.ContentType = "text/xml";

      //We'd like UTF-8.
      context.Response.ContentEncoding = System.Text.Encoding.UTF8;
      //context.Response.ContentEncoding = System.Text.Encoding.UnicodeEncoding; //But no reason you couldn't use UTF-16:
      //context.Response.ContentEncoding = System.Text.Encoding.UTF32; //Or UTF-32
      //context.Response.ContentEncoding = new System.Text.Encoding(500); //Or EBCDIC (500 is the code page for IBM EBCDIC International)
      //context.Response.ContentEncoding = System.Text.Encoding.ASCII; //Or ASCII
      //context.Response.ContentEncoding = new System.Text.Encoding(28591); //Or ISO8859-1
      //context.Response.ContentEncoding = new System.Text.Encoding(1252); //Or Windows-1252 (a version of ISO8859-1, but with 18 useful characters where they were empty spaces)

      //Tell the client don't cache it (it's too volatile)
      //Commenting out NoCache allows the browser to cache the results (so they can view the XML source)
      //But leaves the possiblity that the browser might not request a fresh copy
      //context.Response.Cache.SetCacheability(HttpCacheability.NoCache);

      //And now we tell the browser that it expires immediately, and the cached copy you have should be refreshed
      context.Response.Expires = -1;

      context.Response.Cache.SetAllowResponseInBrowserHistory(true); //"works around an Internet&nbsp;Explorer bug"

      doc.Save(context.Response.Output); //doc saves itself to the textwriter, using the encoding of the text-writer (which comes from response.contentEncoding)

      #region Notes
      /*
       * 1. Use Response.Output, and NOT Response.OutputStream.
       *  Both are streams, but Output is a TextWriter.
       *  When an XmlDocument saves itself to a TextWriter, it will use the encoding
       *  specified by the TextWriter. The XmlDocument will automatically change any
       *  XML declaration node, i.e.:
       *     <?xml version="1.0" encoding="ISO-8859-1"?>
       *  to match the encoding used by the Response.Output's encoding setting
       * 2. The Response.Output TextWriter's encoding settings comes from the
       *  Response.ContentEncoding value.
       * 3. Use doc.Save, not Response.Write(doc.ToString()) or Response.Write(doc.InnerXml)
       * 3. You DON'T want to save the XML to a string, or stuff the XML into a string
       *  and response.Write that, because that
       *   - doesn't follow the encoding specified
       *   - wastes memory
       *
       * To sum up: by Saving to a TextWriter: the XML Declaration node, the XML contents,
       * and the HTML Response content-encoding will all match.
       */
      #endregion Notes
   }

   private XmlDocument GetXmlToShow(HttpContext context)
   {
      //Use context.Request to get the account number they want to return
      //GET /GetPatronInformation.ashx?accountNumber=619

      //Or since this is sample code, pull XML out of your rear:
      XmlDocument doc = new XmlDocument();
      doc.LoadXml("<Patron><Name>Rob Kennedy</Name></Patron>");

      return doc;
   }

   public bool IsReusable { get { return false; } }
}

Read file from line 2 or skip header row

If you want the first line and then you want to perform some operation on file this code will helpful.

with open(filename , 'r') as f:
    first_line = f.readline()
    for line in f:
            # Perform some operations

scroll image with continuous scrolling using marquee tag

Try this:

<marquee behavior="" Height="200px"  direction="up" scroll onmouseover="this.setAttribute('scrollamount', 0, 0);this.stop();" onmouseout="this.setAttribute('scrollamount', 3, 0);this.start();" scrollamount="3" valign="center">

    <img src="images/a.jpg">
        <img src="images/a.jpg">
        <img src="images/a.jpg">
        <img src="images/a.jpg">
        <img src="images/a.jpg">
        <img src="images/a.jpg">
    </marquee>

Unit test naming best practices

the name of the the test case for class Foo should be FooTestCase or something like it (FooIntegrationTestCase or FooAcceptanceTestCase) - since it is a test case. see http://xunitpatterns.com/ for some standard naming conventions like test, test case, test fixture, test method, etc.

Read tab-separated file line into array

You're very close:

while IFS=$'\t' read -r -a myArray
do
 echo "${myArray[0]}"
 echo "${myArray[1]}"
 echo "${myArray[2]}"
done < myfile

(The -r tells read that \ isn't special in the input data; the -a myArray tells it to split the input-line into words and store the results in myArray; and the IFS=$'\t' tells it to use only tabs to split words, instead of the regular Bash default of also allowing spaces to split words as well. Note that this approach will treat one or more tabs as the delimiter, so if any field is blank, later fields will be "shifted" into earlier positions in the array. Is that O.K.?)

How to get multiple counts with one SQL query?

SELECT 
    distributor_id, 
    COUNT(*) AS TOTAL, 
    COUNT(IF(level='exec',1,null)),
    COUNT(IF(level='personal',1,null))
FROM sometable;

COUNT only counts non null values and the DECODE will return non null value 1 only if your condition is satisfied.

how to use LIKE with column name

For SQLLite you will need to concat the strings

select * from list1 l, list2 ll 
WHERE l.name like "%"||ll.alias||"%";

How do I subtract minutes from a date in javascript?

var date=new Date();

//here I am using "-30" to subtract 30 minutes from the current time.
var minute=date.setMinutes(date.getMinutes()-30); 

console.log(minute) //it will print the time and date according to the above condition in Unix-timestamp format.

you can convert Unix timestamp into conventional time by using new Date().for example

var extract=new Date(minute)
console.log(minute)//this will print the time in the readable format.

Android Emulator Error Message: "PANIC: Missing emulator engine program for 'x86' CPUS."

For Ubuntu users

If you are getting PANIC: Missing emulator engine program for 'x86' CPU. this error

Try starting your emulator from the emulator folder in SDK, like above

usama@usama-Aspire-V5-471:~/Android/Sdk/emulator$ ./emulator -avd Pixel_2_API_29

cv2.imshow command doesn't work properly in opencv-python

I faced the same issue. I tried to read an image from IDLE and tried to display it using cv2.imshow(), but the display window freezes and shows pythonw.exe is not responding when trying to close the window.

The post below gives a possible explanation for why this is happening

pythonw.exe is not responding

"Basically, don't do this from IDLE. Write a script and run it from the shell or the script directly if in windows, by naming it with a .pyw extension and double clicking it. There is apparently a conflict between IDLE's own event loop and the ones from GUI toolkits."

When I used imshow() in a script and execute it rather than running it directly over IDLE, it worked.

How to crop an image using PIL?

(left, upper, right, lower) means two points,

  1. (left, upper)
  2. (right, lower)

with an 800x600 pixel image, the image's left upper point is (0, 0), the right lower point is (800, 600).

So, for cutting the image half:

from PIL import Image
img = Image.open("ImageName.jpg")

img_left_area = (0, 0, 400, 600)
img_right_area = (400, 0, 800, 600)

img_left = img.crop(img_left_area)
img_right = img.crop(img_right_area)

img_left.show()
img_right.show()

enter image description here

Coordinate System

The Python Imaging Library uses a Cartesian pixel coordinate system, with (0,0) in the upper left corner. Note that the coordinates refer to the implied pixel corners; the centre of a pixel addressed as (0, 0) actually lies at (0.5, 0.5).

Coordinates are usually passed to the library as 2-tuples (x, y). Rectangles are represented as 4-tuples, with the upper left corner given first. For example, a rectangle covering all of an 800x600 pixel image is written as (0, 0, 800, 600).

How to install JQ on Mac by command-line?

On a Mac, the "most efficient" way to install jq would probably be using homebrew, e.g.

brew install jq

If you want the development version, you could try:

brew install --HEAD jq

but this has various pre-requisites.

Detailed instructions are on the "Installation" page of the jq wiki: https://github.com/stedolan/jq/wiki/Installation

The same page also includes details regarding installation from source, and has notes on installing with MacPorts.

Failed to build gem native extension — Rails install

mkmf is part of the ruby1.9.1-dev package. This package contains the header files needed for extension libraries for Ruby 1.9.1. You need to install the ruby1.9.1-dev package by doing:

sudo apt-get install ruby1.9.1-dev

Then you can install Rails as per normal.

Generally it's easier to just do:

sudo apt-get install ruby-dev

TypeScript error: Type 'void' is not assignable to type 'boolean'

Your code is passing a function as an argument to find. That function takes an element argument (of type Conversation) and returns void (meaning there is no return value). TypeScript describes this as (element: Conversation) => void'

What TypeScript is saying is that the find function doesn't expect to receive a function that takes a Conversation and returns void. It expects a function that takes a Conversations, a number and a Conversation array, and that this function should return a boolean.

So bottom line is that you either need to change your code to pass in the values to find correctly, or else you need to provide an overload to the definition of find in your definition file that accepts a Conversation and returns void.

What does HTTP/1.1 302 mean exactly?

In the term of SEO , 301 and 302 both are good it is depend on situation,

If only one version can be returned (i.e., the other redirects to it), that’s great! This behavior is beneficial because it reduces duplicate content. In the particular case of redirects to trailing slash URLs, our search results will likely show the version of the URL with the 200 response code (most often the trailing slash URL) -- regardless of whether the redirect was a 301 or 302.

Adding Text to DataGridView Row Header

yes you can

DataGridView1.Rows[0].HeaderCell.Value = "my text";

How to format a float in javascript?

If you want the string without round you can use this RegEx (maybe is not the most efficient way... but is really easy)

(2.34567778).toString().match(/\d+\.\d{2}/)[0]
// '2.34'

What's the difference between RANK() and DENSE_RANK() functions in oracle?

rank() : It is used to rank a record within a group of rows.

dense_rank() : The DENSE_RANK function acts like the RANK function except that it assigns consecutive ranks.

Query -

select 
    ENAME,SAL,RANK() over (order by SAL) RANK
from 
    EMP;

Output -

+--------+------+------+
| ENAME  | SAL  | RANK |
+--------+------+------+
| SMITH  |  800 |    1 |
| JAMES  |  950 |    2 |
| ADAMS  | 1100 |    3 |
| MARTIN | 1250 |    4 |
| WARD   | 1250 |    4 |
| TURNER | 1500 |    6 |
+--------+------+------+

Query -

select 
    ENAME,SAL,dense_rank() over (order by SAL) DEN_RANK
from 
    EMP;

Output -

+--------+------+-----------+
| ENAME  | SAL  |  DEN_RANK |
+--------+------+-----------+
| SMITH  |  800 |         1 |
| JAMES  |  950 |         2 |
| ADAMS  | 1100 |         3 |
| MARTIN | 1250 |         4 |
| WARD   | 1250 |         4 |
| TURNER | 1500 |         5 |
+--------+------+-----------+

Reloading submodules in IPython

In IPython 0.12 (and possibly earlier), you can use this:

%load_ext autoreload
%autoreload 2

This is essentially the same as the answer by pv., except that the extension has been renamed and is now loaded using %load_ext.

HTML5 Canvas 100% Width Height of Viewport?

(Expanding upon ????'s answer)

Style the canvas to fill the body. When rendering to the canvas take its size into account.

http://jsfiddle.net/mqFdk/356/

<!DOCTYPE html>
<html>
<head>
    <title>aj</title>
</head>
<body>

    <canvas id="c"></canvas>

</body>
</html>

CSS:

body { 
       margin: 0; 
       padding: 0
     }
#c { 
     position: absolute; 
     width: 100%; 
     height: 100%; 
     overflow: hidden
   }

Javascript:

function redraw() {
    var cc = c.getContext("2d");
    c.width = c.clientWidth;
    c.height = c.clientHeight;
    cc.scale(c.width, c.height);

    // Draw a circle filling the canvas.
    cc.beginPath();
    cc.arc(0.5, 0.5, .5, 0, 2*Math.PI);
    cc.fill();
}

// update on any window size change.
window.addEventListener("resize", redraw);

// first draw
redraw();

pythonic way to do something N times without an index variable?

The _ is the same thing as x. However it's a python idiom that's used to indicate an identifier that you don't intend to use. In python these identifiers don't takes memor or allocate space like variables do in other languages. It's easy to forget that. They're just names that point to objects, in this case an integer on each iteration.

How can I send an email by Java application using GMail, Yahoo, or Hotmail?

Value added:

  • encoding pitfalls in subject, message and display name
  • only one magic property is needed for modern java mail library versions
  • Session.getInstance() recommended over Session.getDefaultInstance()
  • attachment in the same example
  • still works after Google turns off less secure apps: Enable 2-factor authentication in your organization -> turn on 2FA -> generate app password.
    import java.io.File;
    import java.nio.charset.StandardCharsets;
    import java.util.Properties;
    import java.util.logging.Level;
    import java.util.logging.Logger;
    import javax.activation.DataHandler;
    import javax.mail.Message;
    import javax.mail.Session;
    import javax.mail.Transport;
    import javax.mail.internet.InternetAddress;
    import javax.mail.internet.MimeBodyPart;
    import javax.mail.internet.MimeMessage;
    import javax.mail.internet.MimeMultipart;
    import javax.mail.util.ByteArrayDataSource;
    
    public class Gmailer {
      private static final Logger LOGGER = Logger.getLogger(Gmailer.class.getName());
    
      public static void main(String[] args) {
        send();
      }
    
      public static void send() {
        Transport transport = null;
        try {
          String accountEmail = "[email protected]";
          String accountAppPassword = "";
          String displayName = "Display-Name ?";
          String replyTo = "[email protected]";
    
          String to = "[email protected]";
          String cc = "[email protected]";
          String bcc = "[email protected]";
    
          String subject = "Subject ?";
          String message = "<span style='color: red;'>?</span>";
          String type = "html"; // or "plain"
          String mimeTypeWithEncoding = "text/" + type + "; charset=" + StandardCharsets.UTF_8.name();
    
          File attachmentFile = new File("Attachment.pdf");
          // https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types
          String attachmentMimeType = "application/pdf";
          byte[] bytes = ...; // read file to byte array
    
          Properties properties = System.getProperties();
          properties.put("mail.debug", "true");
          // i found that this is the only property necessary for a modern java mail version
          properties.put("mail.smtp.starttls.enable", "true");
          // https://javaee.github.io/javamail/FAQ#getdefaultinstance
          Session session = Session.getInstance(properties);
    
          MimeMessage mimeMessage = new MimeMessage(session);
    
          // probably best to use the account email address, to avoid landing in spam or blacklists
          // not even sure if the server would accept a differing from address
          InternetAddress from = new InternetAddress(accountEmail);
          from.setPersonal(displayName, StandardCharsets.UTF_8.name());
          mimeMessage.setFrom(from);
    
          mimeMessage.setReplyTo(InternetAddress.parse(replyTo));
    
          mimeMessage.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to));
          mimeMessage.setRecipients(Message.RecipientType.CC, InternetAddress.parse(cc));
          mimeMessage.setRecipients(Message.RecipientType.BCC, InternetAddress.parse(bcc));
    
          mimeMessage.setSubject(subject, StandardCharsets.UTF_8.name());
    
          MimeMultipart multipart = new MimeMultipart();
    
          MimeBodyPart messagePart = new MimeBodyPart();
          messagePart.setContent(mimeMessage, mimeTypeWithEncoding);
          multipart.addBodyPart(messagePart);
    
          MimeBodyPart attachmentPart = new MimeBodyPart();
          attachmentPart.setDataHandler(new DataHandler(new ByteArrayDataSource(bytes, attachmentMimeType)));
          attachmentPart.setFileName(attachmentFile.getName());
          multipart.addBodyPart(attachmentPart);
    
          mimeMessage.setContent(multipart);
    
          transport = session.getTransport();
          transport.connect("smtp.gmail.com", 587, accountEmail, accountAppPassword);
          transport.sendMessage(mimeMessage, mimeMessage.getAllRecipients());
        }
        catch(Exception e) {
          // I prefer to bubble up exceptions, so the caller has the info that someting went wrong, and gets a chance to handle it.
          // I also prefer not to force the exception in the signature.
          throw e instanceof RuntimeException ? (RuntimeException) e : new RuntimeException(e);
        }
        finally {
          if(transport != null) {
            try {
              transport.close();
            }
            catch(Exception e) {
              LOGGER.log(Level.WARNING, "failed to close java mail transport: " + e);
            }
          }
        }
      }
    }

AngularJS ng-repeat handle empty list case

you can use ng-if because this is not render in html page and you dont see your html tag in inspect...

<ul ng-repeat="item in items" ng-if="items.length > 0">
    <li>{{item}}<li>
</ul>
<div class="alert alert-info">there is no items!</div>

Excel VBA App stops spontaneously with message "Code execution has been halted"

This problem comes from a strange quirk within Office/Windows.

After developing the same piece of VBA code and running it hundreds of times (literally) over the last couple days I ran into this problem just now. The only thing that has been different is that just prior to experiencing this perplexing problem I accidentally ended the execution of the VBA code with an unorthodox method.

I cleaned out all temp files, rebooted, etc... When I ran the code again after all of this I still got the issue - before I entered the first loop. It makes sense that "press "Debug" button in the popup, then press twice [Ctrl+Break] and after this can continue without stops" because something in the combination of Office/Windows has not released the execution. It is stuck.

The redundant Ctrl+Break action probably resolves the lingering execution.

How to convert an iterator to a stream?

One way is to create a Spliterator from the Iterator and use that as a basis for your stream:

Iterator<String> sourceIterator = Arrays.asList("A", "B", "C").iterator();
Stream<String> targetStream = StreamSupport.stream(
          Spliterators.spliteratorUnknownSize(sourceIterator, Spliterator.ORDERED),
          false);

An alternative which is maybe more readable is to use an Iterable - and creating an Iterable from an Iterator is very easy with lambdas because Iterable is a functional interface:

Iterator<String> sourceIterator = Arrays.asList("A", "B", "C").iterator();

Iterable<String> iterable = () -> sourceIterator;
Stream<String> targetStream = StreamSupport.stream(iterable.spliterator(), false);

image processing to improve tesseract OCR accuracy

As a rule of thumb, I usually apply the following image pre-processing techniques using OpenCV library:

  1. Rescaling the image (it's recommended if you’re working with images that have a DPI of less than 300 dpi):

    img = cv2.resize(img, None, fx=1.2, fy=1.2, interpolation=cv2.INTER_CUBIC)
    
  2. Converting image to grayscale:

    img = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    
  3. Applying dilation and erosion to remove the noise (you may play with the kernel size depending on your data set):

    kernel = np.ones((1, 1), np.uint8)
    img = cv2.dilate(img, kernel, iterations=1)
    img = cv2.erode(img, kernel, iterations=1)
    
  4. Applying blur, which can be done by using one of the following lines (each of which has its pros and cons, however, median blur and bilateral filter usually perform better than gaussian blur.):

    cv2.threshold(cv2.GaussianBlur(img, (5, 5), 0), 0, 255, cv2.THRESH_BINARY + cv2.THRESH_OTSU)[1]
    
    cv2.threshold(cv2.bilateralFilter(img, 5, 75, 75), 0, 255, cv2.THRESH_BINARY + cv2.THRESH_OTSU)[1]
    
    cv2.threshold(cv2.medianBlur(img, 3), 0, 255, cv2.THRESH_BINARY + cv2.THRESH_OTSU)[1]
    
    cv2.adaptiveThreshold(cv2.GaussianBlur(img, (5, 5), 0), 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C, cv2.THRESH_BINARY, 31, 2)
    
    cv2.adaptiveThreshold(cv2.bilateralFilter(img, 9, 75, 75), 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C, cv2.THRESH_BINARY, 31, 2)
    
    cv2.adaptiveThreshold(cv2.medianBlur(img, 3), 255, cv2.ADAPTIVE_THRESH_GAUSSIAN_C, cv2.THRESH_BINARY, 31, 2)
    

I've recently written a pretty simple guide to Tesseract but it should enable you to write your first OCR script and clear up some hurdles that I experienced when things were less clear than I would have liked in the documentation.

In case you'd like to check them out, here I'm sharing the links with you:

How do I import a namespace in Razor View Page?

In ASP.NET MVC 3 Preview1 you can import a namespace on all your razor views with this code in Global.asax.cs

Microsoft.WebPages.Compilation.CodeGeneratorSettings.AddGlobalImport("Namespace.Namespace");

I hope in RTM this gets done through Web.config section.

Wait one second in running program

Wait function using timers, no UI locks.

public void wait(int milliseconds)
{
    var timer1 = new System.Windows.Forms.Timer();
    if (milliseconds == 0 || milliseconds < 0) return;

    // Console.WriteLine("start wait timer");
    timer1.Interval = milliseconds;
    timer1.Enabled  = true;
    timer1.Start();

    timer1.Tick += (s, e) =>
    {
        timer1.Enabled = false;
        timer1.Stop();
        // Console.WriteLine("stop wait timer");
    };

    while (timer1.Enabled)
    {
        Application.DoEvents();
    }
}

Usage: just placing this inside your code that needs to wait:

wait(1000); //wait one second

What are the differences between using the terminal on a mac vs linux?

If you did a new or clean install of OS X version 10.3 or more recent, the default user terminal shell is bash.

Bash is essentially an enhanced and GNU freeware version of the original Bourne shell, sh. If you have previous experience with bash (often the default on GNU/Linux installations), this makes the OS X command-line experience familiar, otherwise consider switching your shell either to tcsh or to zsh, as some find these more user-friendly.

If you upgraded from or use OS X version 10.2.x, 10.1.x or 10.0.x, the default user shell is tcsh, an enhanced version of csh('c-shell'). Early implementations were a bit buggy and the programming syntax a bit weird so it developed a bad rap.

There are still some fundamental differences between mac and linux as Gordon Davisson so aptly lists, for example no useradd on Mac and ifconfig works differently.

The following table is useful for knowing the various unix shells.

sh      The original Bourne shell   Present on every unix system 
ksh     Original Korn shell         Richer shell programming environment than sh 
csh     Original C-shell            C-like syntax; early versions buggy 
tcsh    Enhanced C-shell            User-friendly and less buggy csh implementation 
bash    GNU Bourne-again shell      Enhanced and free sh implementation 
zsh     Z shell                     Enhanced, user-friendly ksh-like shell

You may also find these guides helpful:

http://homepage.mac.com/rgriff/files/TerminalBasics.pdf

http://guides.macrumors.com/Terminal
http://www.ofb.biz/safari/article/476.html

On a final note, I am on Linux (Ubuntu 11) and Mac osX so I use bash and the thing I like the most is customizing the .bashrc (source'd from .bash_profile on OSX) file with aliases, some examples below. I now placed all my aliases in a separate .bash_aliases file and include it with:

if [ -f ~/.bash_aliases ]; then
    . ~/.bash_aliases
fi

in the .bashrc or .bash_profile file.

Note that this is an example of a mac-linux difference because on a Mac you can't have the --color=auto. The first time I did this (without knowing) I redefined ls to be invalid which was a bit alarming until I removed --auto-color !

You may also find https://unix.stackexchange.com/q/127799/10043 useful

# ~/.bash_aliases
# ls variants
#alias l='ls -CF' 
alias la='ls -A' 
alias l='ls -alFtr' 
alias lsd='ls -d .*' 
# Various
alias h='history | tail'
alias hg='history | grep'
alias mv='mv -i' 
alias zap='rm -i'
# One letter quickies:
alias p='pwd'
alias x='exit'
alias {ack,ak}='ack-grep'
# Directories
alias s='cd ..'
alias play='cd ~/play/'
# Rails
alias src='script/rails console'
alias srs='script/rails server'
alias raked='rake db:drop db:create db:migrate db:seed' 
alias rvm-restart='source '\''/home/durrantm/.rvm/scripts/rvm'\'''
alias rrg='rake routes | grep '
alias rspecd='rspec --drb '
#
# DropBox - syncd
WORKBASE="~/Dropbox/97_2012/work"
alias work="cd $WORKBASE"
alias code="cd $WORKBASE/ror/code"
#
# DropNot - NOT syncd !
WORKBASE_GIT="~/Dropnot"
alias {dropnot,not}="cd $WORKBASE_GIT"
alias {webs,ww}="cd $WORKBASE_GIT/webs"
alias {setups,docs}="cd $WORKBASE_GIT/setups_and_docs"
alias {linker,lnk}="cd $WORKBASE_GIT/webs/rails_v3/linker"
#
# git
alias {gsta,gst}='git status' 
# Warning: gst conflicts with gnu-smalltalk (when used).
alias {gbra,gb}='git branch'
alias {gco,go}='git checkout'
alias {gcob,gob}='git checkout -b '
alias {gadd,ga}='git add '
alias {gcom,gc}='git commit'
alias {gpul,gl}='git pull '
alias {gpus,gh}='git push '
alias glom='git pull origin master'
alias ghom='git push origin master'
alias gg='git grep '
#
# vim
alias v='vim'
#
# tmux
alias {ton,tn}='tmux set -g mode-mouse on'
alias {tof,tf}='tmux set -g mode-mouse off'
#
# dmc
alias {dmc,dm}='cd ~/Dropnot/webs/rails_v3/dmc/'
alias wf='cd ~/Dropnot/webs/rails_v3/dmc/dmWorkflow'
alias ws='cd ~/Dropnot/webs/rails_v3/dmc/dmStaffing'

Error: More than one module matches. Use skip-import option to skip importing the component into the closest module

I had this warning when had this in angular.json config:

"prefix": "app_ng"

When changed to "app" all worked perfectly fine.

How to get a list of column names

Yes, you can achieve this by using the following commands:

sqlite> .headers on
sqlite> .mode column

The result of a select on your table will then look like:

id          foo         bar         age         street      address
----------  ----------  ----------  ----------  ----------  ----------
1           val1        val2        val3        val4        val5
2           val6        val7        val8        val9        val10