Programs & Examples On #Xinclude

XInclude is a generic mechanism for merging XML documents, by writing inclusion tags in the parent document.

pip is not able to install packages correctly: Permission denied error

Set up a virtualenv:

% curl -kLso /tmp/get-pip.py https://bootstrap.pypa.io/get-pip.py 
% sudo python /tmp/get-pip.py

These commands install pip into the global site-packages directory.

% sudo pip install virtualenv

and ditto for virtualenv:

% mkdir -p ~/.virtualenvs

I like my virtualenvs under one tree in my home directory called .virtualenvs

% virtualenv ~/.virtualenvs/lxmltest

Creates a virtualenv.

% . ~/.virtualenvs/lxmltest/bin/activate

Removes the need to specify the full path to pip/python in this virtualenv.

% pip install lxml

Alternatively execute ~/.virtualenvs/lxmltest/bin/pip install lxml if you chose not to follow the previous step. Note, I'm not sure how far along you are, so some of these steps can be safely skipped. Of course, if you mess something up, you can always rm -Rf ~/.virtualenvs/lxmltest and start again from a new virtualenv.

ReSharper "Cannot resolve symbol" even when project builds

I also saw similar problems reported in ReSharper which did not lead to compile/runtime errors.

These were mostly seen when using "{x:Type ...}" or "{x:Static ...}" markup, causing ReSharper to report "Cannot resolve symbol 'Type'" or "Cannot resolve symbol 'Static'" errors.

Additionally there were many errors like "Invalid markup extension type: expected type is '<type>', actual type is '...Extension'".

The problem resolved itself when I added a reference to the System.Xaml assembly.

C++ error 'Undefined reference to Class::Function()'

What are you using to compile this? If there's an undefined reference error, usually it's because the .o file (which gets created from the .cpp file) doesn't exist and your compiler/build system is not able to link it.

Also, in your card.cpp, the function should be Card::Card() instead of void Card. The Card:: is scoping; it means that your Card() function is a member of the Card class (which it obviously is, since it's the constructor for that class). Without this, void Card is just a free function. Similarly,

void Card(Card::Rank rank, Card::Suit suit)

should be

Card::Card(Card::Rank rank, Card::Suit suit)

Also, in deck.cpp, you are saying #include "Deck.h" even though you referred to it as deck.h. The includes are case sensitive.

What is the best way to programmatically detect porn images?

I've heard about tools which were using very simple, but quite effective algorithm. The algorithm calculated relative amount of pixels with color value near to some predefined "skin" colours. If that amount is higher than some predefined value then image is considered to be of erotic/pornographic content. Of course that algorithm will give false positive results for close-up face photos and many other things.
Since you are writing about social networking there will be lots of "normal" photos with high amount of skin colour on it, so you shouldn't use this algorithm to deny all pictures with positive result. But you can use it provide some help for moderators, for example flag these pictures with higher priority, so if moderator want to check some new pictures for pornographic content he can start from these pictures.

python dict to numpy structured array

Let me propose an improved method when the values of the dictionnary are lists with the same lenght :

import numpy

def dctToNdarray (dd, szFormat = 'f8'):
    '''
    Convert a 'rectangular' dictionnary to numpy NdArray
    entry 
        dd : dictionnary (same len of list 
    retrun
        data : numpy NdArray 
    '''
    names = dd.keys()
    firstKey = dd.keys()[0]
    formats = [szFormat]*len(names)
    dtype = dict(names = names, formats=formats)
    values = [tuple(dd[k][0] for k in dd.keys())]
    data = numpy.array(values, dtype=dtype)
    for i in range(1,len(dd[firstKey])) :
        values = [tuple(dd[k][i] for k in dd.keys())]
        data_tmp = numpy.array(values, dtype=dtype)
        data = numpy.concatenate((data,data_tmp))
    return data

dd = {'a':[1,2.05,25.48],'b':[2,1.07,9],'c':[3,3.01,6.14]}
data = dctToNdarray(dd)
print data.dtype.names
print data

How to remove undefined and null values from an object using lodash?

To remove undefined, null, and empty string from object

_.omitBy(object, (v) => _.isUndefined(v) || _.isNull(v) || v === '');

How to remove old and unused Docker images

The following command will delete images older than 48 hours.

$ docker image prune --all --filter until=48h

How can I send cookies using PHP curl in addition to CURLOPT_COOKIEFILE?

If the cookie is generated from script, then you can send the cookie manually along with the cookie from the file(using cookie-file option). For example:

# sending manually set cookie
curl_setopt($ch, CURLOPT_HTTPHEADER, array("Cookie: test=cookie"));

# sending cookies from file
curl_setopt($ch, CURLOPT_COOKIEFILE, $ckfile);

In this case curl will send your defined cookie along with the cookies from the file.

If the cookie is generated through javascrript, then you have to trace it out how its generated and then you can send it using the above method(through http-header).

The utma utmc, utmz are seen when cookies are sent from Mozilla. You shouldn't bet worry about these things anymore.

Finally, the way you are doing is alright. Just make sure you are using absolute path for the file names(i.e. /var/dir/cookie.txt) instead of relative one.

Always enable the verbose mode when working with curl. It will help you a lot on tracing the requests. Also it will save lot of your times.

curl_setopt($ch, CURLOPT_VERBOSE, true);

How to print a float with 2 decimal places in Java?

You can use DecimalFormat. One way to use it:

DecimalFormat df = new DecimalFormat();
df.setMaximumFractionDigits(2);
System.out.println(df.format(decimalNumber));

Another one is to construct it using the #.## format.

I find all formatting options less readable than calling the formatting methods, but that's a matter of preference.

WHERE Clause to find all records in a specific month

I find it easier to pass a value as a temporal data type (e.g. DATETIME) then use temporal functionality, specifically DATEADD and DATEPART, to find the start and end dates for the period, in this case the month e.g. this finds the start date and end date pair for the current month, just substitute CURRENT_TIMESTAMP for you parameter of of type DATETIME (note the 1990-01-01 value is entirely arbitrary):

SELECT DATEADD(M, 
          DATEDIFF(M, '1990-01-01T00:00:00.000', CURRENT_TIMESTAMP), 
          '1990-01-01T00:00:00.000'), 
       DATEADD(M, 
          DATEDIFF(M, '1990-01-01T00:00:00.000', CURRENT_TIMESTAMP), 
          '1990-01-31T23:59:59.997')

How to print variables in Perl

You should always include all relevant code when asking a question. In this case, the print statement that is the center of your question. The print statement is probably the most crucial piece of information. The second most crucial piece of information is the error, which you also did not include. Next time, include both of those.

print $ids should be a fairly hard statement to mess up, but it is possible. Possible reasons:

  1. $ids is undefined. Gives the warning undefined value in print
  2. $ids is out of scope. With use strict, gives fatal warning Global variable $ids needs explicit package name, and otherwise the undefined warning from above.
  3. You forgot a semi-colon at the end of the line.
  4. You tried to do print $ids $nIds, in which case perl thinks that $ids is supposed to be a filehandle, and you get an error such as print to unopened filehandle.

Explanations

1: Should not happen. It might happen if you do something like this (assuming you are not using strict):

my $var;
while (<>) {
    $Var .= $_;
}
print $var;

Gives the warning for undefined value, because $Var and $var are two different variables.

2: Might happen, if you do something like this:

if ($something) {
    my $var = "something happened!";
}
print $var;

my declares the variable inside the current block. Outside the block, it is out of scope.

3: Simple enough, common mistake, easily fixed. Easier to spot with use warnings.

4: Also a common mistake. There are a number of ways to correctly print two variables in the same print statement:

print "$var1 $var2";  # concatenation inside a double quoted string
print $var1 . $var2;  # concatenation
print $var1, $var2;   # supplying print with a list of args

Lastly, some perl magic tips for you:

use strict;
use warnings;

# open with explicit direction '<', check the return value
# to make sure open succeeded. Using a lexical filehandle.
open my $fh, '<', 'file.txt' or die $!;

# read the whole file into an array and
# chomp all the lines at once
chomp(my @file = <$fh>);
close $fh;

my $ids  = join(' ', @file);
my $nIds = scalar @file;
print "Number of lines: $nIds\n";
print "Text:\n$ids\n";

Reading the whole file into an array is suitable for small files only, otherwise it uses a lot of memory. Usually, line-by-line is preferred.

Variations:

  • print "@file" is equivalent to $ids = join(' ',@file); print $ids;
  • $#file will return the last index in @file. Since arrays usually start at 0, $#file + 1 is equivalent to scalar @file.

You can also do:

my $ids;
do {
    local $/;
    $ids = <$fh>;
}

By temporarily "turning off" $/, the input record separator, i.e. newline, you will make <$fh> return the entire file. What <$fh> really does is read until it finds $/, then return that string. Note that this will preserve the newlines in $ids.

Line-by-line solution:

open my $fh, '<', 'file.txt' or die $!; # btw, $! contains the most recent error
my $ids;
while (<$fh>) {
    chomp;
    $ids .= "$_ "; # concatenate with string
}
my $nIds = $.; # $. is Current line number for the last filehandle accessed.

How to get the position of a character in Python?

Just for a sake of completeness, if you need to find all positions of a character in a string, you can do the following:

s = 'shak#spea#e'
c = '#'
print([pos for pos, char in enumerate(s) if char == c])

which will print: [4, 9]

Best Java obfuscator?

I think that Proguard is the best. It is also possible to integrate it with your IDE (for example NetBeans). However, consider that if you obfuscate your code it could be difficult to track problems in your logs..

How to keep keys/values in same order as declared?

from collections import OrderedDict
OrderedDict((word, True) for word in words)

contains

OrderedDict([('He', True), ('will', True), ('be', True), ('the', True), ('winner', True)])

If the values are True (or any other immutable object), you can also use:

OrderedDict.fromkeys(words, True)

Convert HTML to NSAttributedString in iOS

The only solution you have right now is to parse the HTML, build up some nodes with given point/font/etc attributes, then combine them together into an NSAttributedString. It's a lot of work, but if done correctly, can be reusable in the future.

How to save a Seaborn plot into a file

You would get an error for using sns.figure.savefig("output.png") in seaborn 0.8.1.

Instead use:

import seaborn as sns

df = sns.load_dataset('iris')
sns_plot = sns.pairplot(df, hue='species', size=2.5)
sns_plot.savefig("output.png")

Input group - two inputs close to each other

I have searched for this a few minutes and i couldn't find any working code.

But now i finaly did it ! Take a look:

<div class="input-group" id="unified-inputs">
<input type="text" class="form-control" placeholder="MinVal" />
<input type="text" class="form-control" placeholder="MaxVal" />
</div>

And css

#unified-inputs.input-group { width: 100%; }
#unified-inputs.input-group input { width: 50% !important; }
#unified-inputs.input-group input:last-of-type { border-left: 0; }

http://jsfiddle.net/4Ln8d7zq/)

What regular expression will match valid international phone numbers?

This is a further optimisation.

\+(9[976]\d|8[987530]\d|6[987]\d|5[90]\d|42\d|3[875]\d|
2[98654321]\d|9[8543210]|8[6421]|6[6543210]|5[87654321]|
4[987654310]|3[9643210]|2[70]|7|1)
\W*\d\W*\d\W*\d\W*\d\W*\d\W*\d\W*\d\W*\d\W*(\d{1,2})$

(i) allows for valid international prefixes
(ii) followed by 9 or 10 digits, with any type or placing of delimeters (except between the last two digits)

This will match:
+1-234-567-8901
+61-234-567-89-01
+46-234 5678901
+1 (234) 56 89 901
+1 (234) 56-89 901
+46.234.567.8901
+1/234/567/8901

Android Studio Run/Debug configuration error: Module not specified

None of the existing answers worked in my case (Android studio 3.5.0). I had to

  1. close all android studio projects
  2. remove the project from the recent projects in android studio wizard
  3. restart android studio
  4. use import option (Import project- Gradle, Eclipse ADT, etc) instead of open an existing project AS project
  5. File -> Sync project with gradle files

Converting dict to OrderedDict

If you can't edit this part of code where your dict was defined you can still order it at any point in any way you want, like this:

from collections import OrderedDict

order_of_keys = ["key1", "key2", "key3", "key4", "key5"]
list_of_tuples = [(key, your_dict[key]) for key in order_of_keys]
your_dict = OrderedDict(list_of_tuples)

How to append text to a text file in C++?

You could use an fstream and open it with the std::ios::app flag. Have a look at the code below and it should clear your head.

...
fstream f("filename.ext", f.out | f.app);
f << "any";
f << "text";
f << "written";
f << "wll";
f << "be append";
...

You can find more information about the open modes here and about fstreams here.

What is $@ in Bash?

Just from reading that i would have never understood that "$@" expands into a list of separate parameters. Whereas, "$*" is one parameter consisting of all the parameters added together.

If it still makes no sense do this.

http://www.thegeekstuff.com/2010/05/bash-shell-special-parameters/

MVC razor form with multiple different submit buttons?

This answer will show you that how to work in asp.net with razor, and to control multiple submit button event. Lets for example we have two button, one button will redirect us to "PageA.cshtml" and other will redirect us to "PageB.cshtml".

@{
  if (IsPost)
    {
       if(Request["btn"].Equals("button_A"))
        {
          Response.Redirect("PageA.cshtml");
        }
      if(Request[&quot;btn"].Equals("button_B"))
        {
          Response.Redirect(&quot;PageB.cshtml&quot;);
        }
  }
}
<form method="post">
   <input type="submit" value="button_A" name="btn"/>;
   <input type="submit" value="button_B" name="btn"/>;          
</form>

Object of class mysqli_result could not be converted to string in

The query() function returns an object, you'll want fetch a record from what's returned from that function. Look at the examples on this page to learn how to print data from mysql

How do I set default value of select box in angularjs

It doesn't set the default value because your model isn't bound to the id or name properties, it's bound to each version object. Try setting the versionID to one of the objects and it should work, ie $scope.item.versionID = $scope.versions[2];

If you want to set by the id property then you need to add the select as syntax:

ng-options="version.id as version.name for version in versions"

http://jsfiddle.net/LrhAQ/1/

How to wait for a process to terminate to execute another process in batch file

Use start /w programname to wait for the end of programname

START /W notepad
ECHO Back from notepad  
START /W wordpad
ECHO Back from wordpad
START /W notepad

Why does make think the target is up to date?

Maybe you have a file/directory named test in the directory. If this directory exists, and has no dependencies that are more recent, then this target is not rebuild.

To force rebuild on these kind of not-file-related targets, you should make them phony as follows:

.PHONY: all test clean

Note that you can declare all of your phony targets there.

A phony target is one that is not really the name of a file; rather it is just a name for a recipe to be executed when you make an explicit request.

ASP.NET MVC Html.ValidationSummary(true) does not display model errors

I know this is kind of old and has been marked as answers with 147 up votes, but there is something else to consider.

You can have all the model errors, the property named and string.Empty keys alike, be shown in the ValidationSummary if you need to. There is an overload in the ValidationSummary that will do this.

    //   excludePropertyErrors:
    //   true to have the summary display model-level errors only, or false to have
    //   the summary display all errors.
    public static MvcHtmlString ValidationSummary(this HtmlHelper htmlHelper, bool excludePropertyErrors);

enter image description here

PHP random string generator

Finally I have found a solution to get random and unique values.

My solution is:

substr(md5(time()), 0, 12)

time always return a timestamp, and it is always unique. You can use it with MD5 to make it better.

MVC ajax json post to controller action method

Below is how I got this working.

The Key point was: I needed to use the ViewModel associated with the view in order for the runtime to be able to resolve the object in the request.

[I know that that there is a way to bind an object other than the default ViewModel object but ended up simply populating the necessary properties for my needs as I could not get it to work]

[HttpPost]  
  public ActionResult GetDataForInvoiceNumber(MyViewModel myViewModel)  
  {            
     var invoiceNumberQueryResult = _viewModelBuilder.HydrateMyViewModelGivenInvoiceDetail(myViewModel.InvoiceNumber, myViewModel.SelectedCompanyCode);
     return Json(invoiceNumberQueryResult, JsonRequestBehavior.DenyGet);
  }

The JQuery script used to call this action method:

var requestData = {
         InvoiceNumber: $.trim(this.value),
         SelectedCompanyCode: $.trim($('#SelectedCompanyCode').val())
      };


      $.ajax({
         url: '/en/myController/GetDataForInvoiceNumber',
         type: 'POST',
         data: JSON.stringify(requestData),
         dataType: 'json',
         contentType: 'application/json; charset=utf-8',
         error: function (xhr) {
            alert('Error: ' + xhr.statusText);
         },
         success: function (result) {
            CheckIfInvoiceFound(result);
         },
         async: true,
         processData: false
      });

Unicode character for "X" cancel / close?

HTML

? &#x2715; ? &#x2713;
? &#x2716; ? &#x2714;

? &#x2717;
? &#x2718;

× &#x00d7; &times;

CSS

If you want to use the above characters from CSS (like i.e: in an :before or :after pseudo) simply use the escaped \ Unicode HEX value, like for example:

_x000D_
_x000D_
[class^="ico-"], [class*=" ico-"]{
  font: normal 1em/1 Arial, sans-serif;
  display: inline-block;
}


.ico-times:before{ content: "\2716"; }
.ico-check:before{ content: "\2714"; }
_x000D_
<i class="ico-times" role="img" aria-label="Cancel"></i>
<i class="ico-check" role="img" aria-label="Accept"></i>
_x000D_
_x000D_
_x000D_

Use examples for different languages:

  • &#x2715; HTML
  • '\2715' CSS like i.e: .clear:before { content: '\2715'; }
  • '\u2715' JavaScript string

https://home.unicode.org/

Communication between tabs or windows

Checkout AcrossTabs - Easy communication between cross-origin browser tabs. It uses a combination of postMessage and sessionStorage API to make communication much easier and reliable.


There are different approaches and each one has its own advantages and disadvantages. Lets discuss each:

  1. LocalStorage

    Pros:

    1. Web storage can be viewed simplistically as an improvement on cookies, providing much greater storage capacity. If you look at the Mozilla source code we can see that 5120KB (5MB which equals 2.5 Million chars on Chrome) is the default storage size for an entire domain. This gives you considerably more space to work with than a typical 4KB cookie.
    2. The data is not sent back to the server for every HTTP request (HTML, images, JavaScript, CSS, etc) - reducing the amount of traffic between client and server.
    3. The data stored in localStorage persists until explicitly deleted. Changes made are saved and available for all current and future visits to the site.

    Cons:

    1. It works on same-origin policy. So, data stored will only be able available on the same origin.
  2. Cookies

    Pros:

    1. Compared to others, there's nothing AFAIK.

    Cons:

    1. The 4K limit is for the entire cookie, including name, value, expiry date etc. To support most browsers, keep the name under 4000 bytes, and the overall cookie size under 4093 bytes.
    2. The data is sent back to the server for every HTTP request (HTML, images, JavaScript, CSS, etc) - increasing the amount of traffic between client and server.

      Typically, the following are allowed:

      • 300 cookies in total
      • 4096 bytes per cookie
      • 20 cookies per domain
      • 81920 bytes per domain(Given 20 cookies of max size 4096 = 81920 bytes.)
  3. sessionStorage

    Pros:

    1. It is similar to localStorage.
    2. Changes are only available per window (or tab in browsers like Chrome and Firefox). Changes made are saved and available for the current page, as well as future visits to the site on the same window. Once the window is closed, the storage is deleted

    Cons:

    1. The data is available only inside the window/tab in which it was set.
    2. The data is not persistent i.e. it will be lost once the window/tab is closed.
    3. Like localStorage, tt works on same-origin policy. So, data stored will only be able available on the same origin.
  4. PostMessage

    Pros:

    1. Safely enables cross-origin communication.
    2. As a data point, the WebKit implementation (used by Safari and Chrome) doesn't currently enforce any limits (other than those imposed by running out of memory).

    Cons:

    1. Need to open a window from the current window and then can communicate only as long as you keep the windows open.
    2. Security concerns - Sending strings via postMessage is that you will pick up other postMessage events published by other JavaScript plugins, so be sure to implement a targetOrigin and a sanity check for the data being passed on to the messages listener.
  5. A combination of PostMessage + SessionStorage

    Using postMessage to communicate between multiple tabs and at the same time using sessionStorage in all the newly opened tabs/windows to persist data being passed. Data will be persisted as long as the tabs/windows remain opened. So, even if the opener tab/window gets closed, the opened tabs/windows will have the entire data even after getting refreshed.

I have written a JavaScript library for this, named AcrossTabs which uses postMessage API to communicate between cross-origin tabs/windows and sessionStorage to persist the opened tabs/windows identity as long as they live.

Adding padding to a tkinter widget only on one side

There are multiple ways of doing that you can use either place or grid or even the packmethod.

Sample code:

from tkinter import *
root = Tk()

l = Label(root, text="hello" )
l.pack(padx=6, pady=4) # where padx and pady represent the x and y axis respectively
# well you can also use side=LEFT inside the pack method of the label widget.

To place a widget to on basis of columns and rows , use the grid method:

but = Button(root, text="hello" )
but.grid(row=0, column=1)

Identifying Exception Type in a handler Catch Block

You should always catch exceptions as concrete as possible, so you should use

try
{
    //code
}
catch (Web2PDFException ex)
{
    //Handle the exception here
}

You chould of course use something like this if you insist:

try
{
}
catch (Exception err)
{
    if (err is Web2PDFException)
    {
        //Code
    }
}

Check if a value is in an array (C#)

Note: The question is about arrays of strings. The mentioned routines are not to be mixed with the .Contains method of single strings.

I would like to add an extending answer referring to different C# versions and because of two reasons:

  • The accepted answer requires Linq which is perfectly idiomatic C# while it does not come without costs, and is not available in C# 2.0 or below. When an array is involved, performance may matter, so there are situations where you want to stay with Array methods.

  • No answer directly attends to the question where it was asked also to put this in a function (As some answers are also mixing strings with arrays of strings, this is not completely unimportant).

Array.Exists() is a C#/.NET 2.0 method and needs no Linq. Searching in arrays is O(n). For even faster access use HashSet or similar collections.

Since .NET 3.5 there also exists a generic method Array<T>.Exists() :

public void PrinterSetup(string[] printer)
{
   if (Array.Exists(printer, x => x == "jupiter"))
   {
      Process.Start("BLAH BLAH CODE TO ADD PRINTER VIA WINDOWS EXEC");
   }
}

You could write an own extension method (C# 3.0 and above) to add the syntactic sugar to get the same/similar ".Contains" as for strings for all arrays without including Linq:

// Using the generic extension method below as requested.
public void PrinterSetup(string[] printer)
{
   if (printer.ArrayContains("jupiter"))
   {
      Process.Start("BLAH BLAH CODE TO ADD PRINTER VIA WINDOWS EXEC");
   }
}

public static bool ArrayContains<T>(this T[] thisArray, T searchElement)
{
   // If you want this to find "null" values, you could change the code here
   return Array.Exists<T>(thisArray, x => x.Equals(searchElement));
}

In this case this ArrayContains() method is used and not the Contains method of Linq.

The elsewhere mentioned .Contains methods refer to List<T>.Contains (since C# 2.0) or ArrayList.Contains (since C# 1.1), but not to arrays itself directly.

The iOS Simulator deployment targets is set to 7.0, but the range of supported deployment target version for this platform is 8.0 to 12.1

for cordova developers having this issue

try to set

<preference name="deployment-target" value="8.0" />

in confix.xml

Do copyright dates need to be updated?

The copyright notice on a work establishes a claim to copyright. The date on the notice establishes how far back the claim is made. This means if you update the date, you are no longer claiming the copyright for the original date and that means if somebody has copied the work in the meantime and they claim its theirs on the ground that their publishing the copy was before your claim, then it will be difficult to establish who is the originator of the work.

Therefore, if the claim is based on common law copyright (not formally registered), then the date should be the date of first publication. If the claim is a registered copyright, then the date should be the date claimed in the registration. In cases where the work was substantially revised you may establish a new copyright claim to the revised work by adding another copyright notice with a newer date or by adding an additional date to the existing notice as in "© 2000, 2010". Again, the added date establishes how far back the claim is made on the revision.

Write HTML to string

You can use ASP.NET to generate your HTML outside the context of web pages. Here's an article that shows how it can be done.

Get device token for push notification

To get Token Device you can do by some steps:

1) Enable APNS (Apple Push Notification Service) for both Developer Certification and Distribute Certification, then redownload those two file.

2) Redownload both Developer Provisioning and Distribute Provisioning file.

3) In Xcode interface: setting provisioning for PROJECT and TARGETS with two file provisioning have download.

4) Finally, you need to add the code below in AppDelegate file to get Token Device (note: run app in real device).

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    
     [self.window addSubview:viewController.view];
     [self.window makeKeyAndVisible];

     NSLog(@"Registering for push notifications...");    
     [[UIApplication sharedApplication] registerForRemoteNotificationTypes:
 (UIRemoteNotificationTypeSound | UIRemoteNotificationTypeAlert)];
     return YES;
}

- (void)application:(UIApplication *)app didRegisterForRemoteNotificationsWithDeviceToken:(NSData *)deviceToken { 
     NSString *str = [NSString stringWithFormat:@"Device Token=%@",deviceToken];
     NSLog(@"%@", str);
}

- (void)application:(UIApplication *)app didFailToRegisterForRemoteNotificationsWithError:(NSError *)err { 
     NSString *str = [NSString stringWithFormat: @"Error: %@", err];
     NSLog(@"%@",str);
}

jQuery AJAX form data serialize using PHP

<form method="post" name="myForm" id="myForm">

replace with above form tag remove action from form tag. and set url : "check.php" in ajax in your case first it goes to jQuery ajax then submit again the form. that's why it's creating issue.

i know i'm too late for this reply but i think it would help.

if checkbox is checked, do this

Why not use the built in events?

$('#checkbox').click(function(e){
    if(e.target.checked) {
     // code to run if checked
        console.log('Checked');

     } else {

     //code to run if unchecked
        console.log('Unchecked');
     }
});

System.BadImageFormatException: Could not load file or assembly

My cause was different I referenced a web service then I got this message.

Then I changed my target .Net Framework 4.0 to .Net Framework 2.0 and re-refer my webservice. After a few changes problem solved. There is no error worked fine.

hope this helps!

How to convert a number to string and vice versa in C++

I stole this convienent class from somewhere here at StackOverflow to convert anything streamable to a string:

// make_string
class make_string {
public:
  template <typename T>
  make_string& operator<<( T const & val ) {
    buffer_ << val;
    return *this;
  }
  operator std::string() const {
    return buffer_.str();
  }
private:
  std::ostringstream buffer_;
};

And then you use it as;

string str = make_string() << 6 << 8 << "hello";

Quite nifty!

Also I use this function to convert strings to anything streamable, althrough its not very safe if you try to parse a string not containing a number; (and its not as clever as the last one either)

// parse_string
template <typename RETURN_TYPE, typename STRING_TYPE>
RETURN_TYPE parse_string(const STRING_TYPE& str) {
  std::stringstream buf;
  buf << str;
  RETURN_TYPE val;
  buf >> val;
  return val;
}

Use as:

int x = parse_string<int>("78");

You might also want versions for wstrings.

How to test an Internet connection with bash?

If your local nameserver is down,

ping 4.2.2.1

is an easy-to-remember always-up IP (it's actually a nameserver, even).

Reading from stdin

You can do something like this to read 10 bytes:

char buffer[10];
read(STDIN_FILENO, buffer, 10);

remember read() doesn't add '\0' to terminate to make it string (just gives raw buffer).

To read 1 byte at a time:

char ch;
while(read(STDIN_FILENO, &ch, 1) > 0)
{
 //do stuff
}

and don't forget to #include <unistd.h>, STDIN_FILENO defined as macro in this file.

There are three standard POSIX file descriptors, corresponding to the three standard streams, which presumably every process should expect to have:

Integer value   Name
       0        Standard input (stdin)
       1        Standard output (stdout)
       2        Standard error (stderr)

So instead STDIN_FILENO you can use 0.

Edit:
In Linux System you can find this using following command:

$ sudo grep 'STDIN_FILENO' /usr/include/* -R | grep 'define'
/usr/include/unistd.h:#define   STDIN_FILENO    0   /* Standard input.  */

Notice the comment /* Standard input. */

Initializing ArrayList with some predefined values

How about using overloaded ArrayList constructor.

 private ArrayList<String> symbolsPresent = new ArrayList<String>(Arrays.asList(new String[] {"One","Two","Three","Four"}));

ExecuteNonQuery: Connection property has not been initialized.

You are not initializing connection.That's why this kind of error is coming to you.

Your code:

cmd.InsertCommand = new SqlCommand("INSERT INTO Application VALUES (@EventLog, @TimeGenerated, @EventType, @SourceName, @ComputerName, @InstanceId, @Message) ");

Corrected code:

cmd.InsertCommand = new SqlCommand("INSERT INTO Application VALUES (@EventLog, @TimeGenerated, @EventType, @SourceName, @ComputerName, @InstanceId, @Message) ",connection1);

XML parsing of a variable string in JavaScript

Most examples on the web (and some presented above) show how to load an XML from a file in a browser compatible manner. This proves easy, except in the case of Google Chrome which does not support the document.implementation.createDocument() method. When using Chrome, in order to load an XML file into a XmlDocument object, you need to use the inbuilt XmlHttp object and then load the file by passing it's URI.

In your case, the scenario is different, because you want to load the XML from a string variable, not a URL. For this requirement however, Chrome supposedly works just like Mozilla (or so I've heard) and supports the parseFromString() method.

Here is a function I use (it's part of the Browser compatibility library I'm currently building):

function LoadXMLString(xmlString)
{
  // ObjectExists checks if the passed parameter is not null.
  // isString (as the name suggests) checks if the type is a valid string.
  if (ObjectExists(xmlString) && isString(xmlString))
  {
    var xDoc;
    // The GetBrowserType function returns a 2-letter code representing
    // ...the type of browser.
    var bType = GetBrowserType();

    switch(bType)
    {
      case "ie":
        // This actually calls into a function that returns a DOMDocument 
        // on the basis of the MSXML version installed.
        // Simplified here for illustration.
        xDoc = new ActiveXObject("MSXML2.DOMDocument")
        xDoc.async = false;
        xDoc.loadXML(xmlString);
        break;
      default:
        var dp = new DOMParser();
        xDoc = dp.parseFromString(xmlString, "text/xml");
        break;
    }
    return xDoc;
  }
  else
    return null;
}

LINQ: Select where object does not contain items from list

Try this simple LINQ:

//For a file list/array
var files = Directory.GetFiles(folderPath, "*.*", SearchOption.AllDirectories);

//simply use Where ! x.Contains
var notContain = files.Where(x => ! x.Contains(@"\$RECYCLE.BIN\")).ToList();

//Or use Except()
var containing = files.Where(x => x.Contains(@"\$RECYCLE.BIN\")).ToList();
    notContain = files.Except(containing).ToList();

Getting unique items from a list

Use a HashSet<T>. For example:

var items = "A B A D A C".Split(' ');
var unique_items = new HashSet<string>(items);
foreach (string s in unique_items)
    Console.WriteLine(s);

prints

A
B
D
C

How to truncate a foreign key constrained table?

Just use CASCADE

TRUNCATE "products" RESTART IDENTITY CASCADE;

But be ready for cascade deletes )

PHP Fatal error: Call to undefined function mssql_connect()

I am using IIS and mysql (directly downloaded, without wamp or xampp) My php was installed in c:\php I was getting the error of "call to undefined function mysql_connect()" For me the change of extension_dir worked. This is what I did. In the php.ini, Originally, I had this line

; On windows: extension_dir = "ext"

I changed it to:

; On windows: extension_dir = "C:\php\ext"

And it worked. Of course, I did the other things also like uncommenting the dll extensions etc, as explained in others remarks.

Merge Cell values with PHPExcel - PHP

$this->excel->setActiveSheetIndex(0)->mergeCells("A".($p).":B".($p)); for dynamic merging of cells

Iterating over Typescript Map

This worked for me. TypeScript Version: 2.8.3

for (const [key, value] of Object.entries(myMap)) { 
    console.log(key, value);
}

How to generate UML diagrams (especially sequence diagrams) from Java code?

Another modelling tool for Java is (my) website GitUML. Generate UML diagrams from Java or Python code stored in GitHub repositories.

One key idea with GitUML is to address one of the problems with "documentation": that diagrams are always out of date. With GitUML, diagrams automatically update when you push code using git.

Browse through community UML diagrams, there are some Java design patterns there. Surf through popular GitHub repositories and visualise the architectures and patterns in them.

diagram browser

Create diagrams using point and click. There is no drag drop editor, just click on the classes in the repository tree that you want to visualise:

select the java classes you want to visualise

The underlying technology is PlantUML based, which means you can refine your diagrams with additional PlantUML markup.

log4net hierarchy and logging levels

Here is some code telling about priority of all log4net levels:

TraceLevel(Level.All); //-2147483648

TraceLevel(Level.Verbose);   //  10 000
TraceLevel(Level.Finest);    //  10 000
    
TraceLevel(Level.Trace);     //  20 000
TraceLevel(Level.Finer);     //  20 000
    
TraceLevel(Level.Debug);     //  30 000
TraceLevel(Level.Fine);      //  30 000
    
TraceLevel(Level.Info);      //  40 000
TraceLevel(Level.Notice);    //  50 000
    
TraceLevel(Level.Warn);      //  60 000
TraceLevel(Level.Error);     //  70 000
TraceLevel(Level.Severe);    //  80 000
TraceLevel(Level.Critical);  //  90 000
TraceLevel(Level.Alert);     // 100 000
TraceLevel(Level.Fatal);     // 110 000
TraceLevel(Level.Emergency); // 120 000
    
TraceLevel(Level.Off); //2147483647


private static void TraceLevel(log4net.Core.Level level)
{
   Debug.WriteLine("{0} = {1}", level, level.Value);
}

How to find the port for MS SQL Server 2008?

I solved the problem by enabling the TCP/IP using the SQL Server Configuration Manager under Protocols for SQLEXPRESS2008, i restarted the service and now the "Server is listening on" shows up in the ERRORLOG file

Is there a way to create multiline comments in Python?

A multiline comment doesn't actually exist in Python. The below example consists of an unassigned string, which is validated by Python for syntactical errors.

A few text editors, like Notepad++, provide us shortcuts to comment out a written piece of code or words.

def foo():
    "This is a doc string."
    # A single line comment
    """
       This
       is a multiline
       comment/String
    """
    """
    print "This is a sample foo function"
    print "This function has no arguments"
    """
    return True

Also, Ctrl + K is a shortcut in Notepad++ to block comment. It adds a # in front of every line under the selection. Ctrl + Shift + K is for block uncomment.

Fastest Convert from Collection to List<T>

you can convert like below code snippet

Collection<A> obj=new Collection<return ListRetunAPI()>

What is the difference between NULL, '\0' and 0?

All three define the meaning of zero in different context.

  • pointer context - NULL is used and means the value of the pointer is 0, independent of whether it is 32bit or 64bit (one case 4 bytes the other 8 bytes of zeroes).
  • string context - the character representing the digit zero has a hex value of 0x30, whereas the NUL character has hex value of 0x00 (used for terminating strings).

These three are always different when you look at the memory:

NULL - 0x00000000 or 0x00000000'00000000 (32 vs 64 bit)
NUL - 0x00 or 0x0000 (ascii vs 2byte unicode)
'0' - 0x20

I hope this clarifies it.

Facebook Graph API, how to get users email?

Open base_facebook.php Add Access_token at function getLoginUrl()

array_merge(array(
                  'access_token' => $this->getAccessToken(),
                  'client_id' => $this->getAppId(),
                  'redirect_uri' => $currentUrl, // possibly overwritten
                  'state' => $this->state),
             $params);

and Use scope for Email Permission

if ($user) {
   echo $logoutUrl = $facebook->getLogoutUrl();
} else {
   echo $loginUrl = $facebook->getLoginUrl(array('scope' => 'email,read_stream'));
}

How do I output the results of a HiveQL query to CSV?

If you are using HUE this is fairly simple as well. Simply go to the Hive editor in HUE, execute your hive query, then save the result file locally as XLS or CSV, or you can save the result file to HDFS.

Are table names in MySQL case sensitive?

It depends upon lower_case_table_names system variable:

show variables where Variable_name='lower_case_table_names'

There are three possible values for this:

  • 0 - lettercase specified in the CREATE TABLE or CREATE DATABASE statement. Name comparisons are case sensitive.
  • 1 - Table names are stored in lowercase on disk and name comparisons are not case sensitive.
  • 2 - lettercase specified in the CREATE TABLE or CREATE DATABASE statement, but MySQL converts them to lowercase on lookup. Name comparisons are not case sensitive.

Documentation

'foo' was not declared in this scope c++

In general, in C++ functions have to be declared before you call them. So sometime before the definition of getSkewNormal(), the compiler needs to see the declaration:

double integrate (double start, double stop, int numSteps, Evaluatable evalObj);

Mostly what people do is put all the declarations (only) in the header file, and put the actual code -- the definitions of the functions and methods -- into a separate source (*.cc or *.cpp) file. This neatly solves the problem of needing all the functions to be declared.

Maven: How do I activate a profile from command line?

Activation by system properties can be done as follows

<activation>
    <property>
        <name>foo</name>
        <value>bar</value>
    </property>
</activation>

And run the mvn build with -D to set system property

mvn clean install -Dfoo=bar

This method also helps select profiles in transitive dependency of project artifacts.

What does body-parser do with express?

These are all a matter of convenience.

Basically, if the question were 'Do we need to use body-parser?' The answer is 'No'. We can come up with the same information from the client-post-request using a more circuitous route that will generally be less flexible and will increase the amount of code we have to write to get the same information.

This is kind of the same as asking 'Do we need to use express to begin with?' Again, the answer there is no, and again, really it all comes down to saving us the hassle of writing more code to do the basic things that express comes with 'built-in'.

On the surface - body-parser makes it easier to get at the information contained in client requests in a variety of formats instead of making you capture the raw data streams and figuring out what format the information is in, much less manually parsing that information into useable data.

How to list the files in current directory?

Try this,to retrieve all files inside folder and sub-folder

public static void main(String[]args)
    {
        File curDir = new File(".");
        getAllFiles(curDir);
    }
    private static void getAllFiles(File curDir) {

        File[] filesList = curDir.listFiles();
        for(File f : filesList){
            if(f.isDirectory())
                getAllFiles(f);
            if(f.isFile()){
                System.out.println(f.getName());
            }
        }

    }

To retrieve files/folder only

public static void main(String[]args)
    {
        File curDir = new File(".");
        getAllFiles(curDir);
    }
    private static void getAllFiles(File curDir) {

        File[] filesList = curDir.listFiles();
        for(File f : filesList){
            if(f.isDirectory())
                System.out.println(f.getName());
            if(f.isFile()){
                System.out.println(f.getName());
            }
        }

    }

How to create a project from existing source in Eclipse and then find it?

While creating a project from a full folder may or may not work within the workspace, there's a condition outside of the workspace that prevents starting a new project with a full folder.

This is relevant if you use numerous folder locations for sources, for example an htdocs or www folder for web projects, and a different location for desktop Java applications.

The condition mentioned occurs when Eclipse is told to create a new project, and given a full folder outside the workspace. Eclipse will say the folder isn't empty, and prevent creating a new project within the given folder. I haven't found a way around this, and any solution requires extra steps.

My favorite solution is as follows

  1. Rename the full folder with an appended "Original" or "Backup.
  2. Create the Eclipse project with the name of the full folder before the folder was renamed.
  3. Copy all the relabeled full folders contents into the new project folder.

Eclipse should make a new project, and update that project with the new folder contents as it scans for changes. The existing sources are now part of the new project.

Although you had to perform three extra steps, you now have a backup with the original sources available, and are also able to use a copy of them in an existing project. If storage space is a concern, simply move/cut the source rather than fully copy the original folder contents.

Adding an onclick function to go to url in JavaScript?

Simply use this

onclick="location.href='pageurl.html';"

How to set order of repositories in Maven settings.xml

Also, consider to use a repository manager such as Nexus and configure all your repositories there.

Is background-color:none valid CSS?

.class {
    background-color:none;
}

This is not a valid property. W3C validator will display following error:

Value Error : background-color none is not a background-color value : none

transparent may have been selected as better term instead of 0 or none values during the development of specification of CSS.

Convert from DateTime to INT

Or, once it's already in SSIS, you could create a derived column (as part of some data flow task) with:

(DT_I8)FLOOR((DT_R8)systemDateTime)

But you'd have to test to doublecheck.

AngularJS : Why ng-bind is better than {{}} in angular?

There is some flickering problem in {{ }} like when you refresh the page then for a short spam of time expression is seen.So we should use ng-bind instead of expression for data depiction.

What is the difference between a candidate key and a primary key?

There is no difference. A primary key is a candidate key. By convention one candidate key in a relation is usually chosen to be the "primary" one but the choice is essentially arbitrary and a matter of convenience for database users/designers/developers. It doesn't make a "primary" key fundamentally any different to any other candidate key.

Using the value in a cell as a cell reference in a formula?

Use INDIRECT()

=SUM(INDIRECT(<start cell here> & ":" & <end cell here>))

Passing arguments to an interactive program non-interactively

Just want to add one more way. Found it elsewhere, and is quite simple. Say I want to pass yes for all the prompts at command line for a command "execute_command", Then I would simply pipe yes to it.

yes | execute_command

This will use yes as the answer to all yes/no prompts.

Find where python is installed (if it isn't default dir)

Platform independent solution in one line is

Python 2:

python -c "import sys; print sys.executable"

Python 3:

python -c "import sys; print(sys.executable)"

How to unzip files programmatically in Android?

Based on zapl's answer, adding try() around Closeable's closes the streams automatically after use.

public static void unzip(File zipFile, File targetDirectory) {
    try (FileInputStream fis = new FileInputStream(zipFile)) {
        try (BufferedInputStream bis = new BufferedInputStream(fis)) {
            try (ZipInputStream zis = new ZipInputStream(bis)) {
                ZipEntry ze;
                int count;
                byte[] buffer = new byte[Constant.DefaultBufferSize];
                while ((ze = zis.getNextEntry()) != null) {
                    File file = new File(targetDirectory, ze.getName());
                    File dir = ze.isDirectory() ? file : file.getParentFile();
                    if (!dir.isDirectory() && !dir.mkdirs())
                        throw new FileNotFoundException("Failed to ensure directory: " + dir.getAbsolutePath());
                    if (ze.isDirectory())
                        continue;
                    try (FileOutputStream fout = new FileOutputStream(file)) {
                        while ((count = zis.read(buffer)) != -1)
                            fout.write(buffer, 0, count);
                    }
                }
            }
        }
    } catch (Exception ex) {
        //handle exception
    }
}

Using Constant.DefaultBufferSize (65536) gotten from C# .NET 4 Stream.CopyTo from Jon Skeet's answer here: https://stackoverflow.com/a/411605/1876355

I always just see posts using byte[1024] or byte[4096] buffer, never knew it can be much larger which improves performance and is still working perfectly normal.

Here is the Stream Source code: https://referencesource.microsoft.com/#mscorlib/system/io/stream.cs

//We pick a value that is the largest multiple of 4096 that is still smaller than the large object heap threshold (85K).
// The CopyTo/CopyToAsync buffer is short-lived and is likely to be collected at Gen0, and it offers a significant
// improvement in Copy performance.

private const int _DefaultCopyBufferSize = 81920;

However, I dialed it back to 65536 which is also a multiple of 4096 just to be safe.

Wait .5 seconds before continuing code VB.net

The problem with Threading.Thread.SLeep(2000) is that it executes first in my VB.Net program. This

Imports VB = Microsoft.VisualBasic

Public Sub wait(ByVal seconds As Single)
    Static start As Single
    start = VB.Timer()
    Do While VB.Timer() < start + seconds
        System.Windows.Forms.Application.DoEvents()
    Loop
End Sub

worked flawlessly.

Full width image with fixed height

Set the height of the parent element, and give that the width. Then use a background image with the rule "background-size: cover"

    .parent {
       background-image: url(../img/team/bgteam.jpg);
       background-repeat: no-repeat;
       background-position: center center;
       -webkit-background-size: cover;
       background-size: cover;
    }

Why es6 react component works only with "export default"?

Add { } while importing and exporting: export { ... }; | import { ... } from './Template';

exportimport { ... } from './Template'

export defaultimport ... from './Template'


Here is a working example:

// ExportExample.js
import React from "react";

function DefaultExport() {
  return "This is the default export";
}

function Export1() {
  return "Export without default 1";
}

function Export2() {
  return "Export without default 2";
}

export default DefaultExport;
export { Export1, Export2 };

// App.js
import React from "react";
import DefaultExport, { Export1, Export2 } from "./ExportExample";

export default function App() {
  return (
    <>
      <strong>
        <DefaultExport />
      </strong>
      <br />
      <Export1 />
      <br />
      <Export2 />
    </>
  );
}

??Working sandbox to play around: https://codesandbox.io/s/export-import-example-react-jl839?fontsize=14&hidenavigation=1&theme=dark

Uncaught SyntaxError: Failed to execute 'querySelector' on 'Document'

Although this is valid in HTML, you can't use an ID starting with an integer in CSS selectors.

As pointed out, you can use getElementById instead, but you can also still achieve the same with a querySelector:

document.querySelector("[id='22']")

Get names of all files from a folder with Ruby

In Ruby 2.5 you can now use Dir.children. It gets filenames as an array except for "." and ".."

Example:

Dir.children("testdir")   #=> ["config.h", "main.rb"]

http://ruby-doc.org/core-2.5.0/Dir.html#method-c-children

Why I get 'list' object has no attribute 'items'?

If you don't care about the type of the numbers you can simply use:

qs[0].values()

Creating Dynamic button with click event in JavaScript

Firstly, you need to change this line:

element.setAttribute("onclick", alert("blabla"));

To something like this:

element.setAttribute("onclick", function() { alert("blabla"); });

Secondly, you may have browser compatibility issues when attaching events that way. You might need to use .attachEvent / .addEvent, depending on which browser. I haven't tried manually setting event handlers for a while, but I remember firefox and IE treating them differently.

allowing only alphabets in text box using java script

:::::HTML:::::

<input type="text" onkeypress="return lettersValidate(event)" />

Only letters no spaces

::::JS::::::::

// ===================== Allow - Only Letters ===============================================================

function lettersValidate(key) {
    var keycode = (key.which) ? key.which : key.keyCode;

    if ((keycode > 64 && keycode < 91) || (keycode > 96 && keycode < 123))  
    {     
           return true;    
    }
    else
    {
        return false;
    }
         
}
 

ActiveMQ connection refused

I encountered a similar problem when I was using the below to obtain connection factory ConnectionFactory factory = new
ActiveMQConnectionFactory("admin","admin","tcp://:61616");

Its resolved when I changed it to the below

ConnectionFactory factory = new ActiveMQConnectionFactory("tcp://:61616");

The below then showed that my Q size was increasing.. http://:8161/admin/queues.jsp

Check if a string is a date value

This callable function works perfectly, returns true for valid date. Be sure to call using a date on ISO format (yyyy-mm-dd or yyyy/mm/dd):

function validateDate(isoDate) {

    if (isNaN(Date.parse(isoDate))) {
        return false;
    } else {
        if (isoDate != (new Date(isoDate)).toISOString().substr(0,10)) {
            return false;
        }
    }
    return true;
}

java howto ArrayList push, pop, shift, and unshift

Underscore-java library contains methods push(values), pop(), shift() and unshift(values).

Code example:

import com.github.underscore.U:

List<String> strings = Arrays.asList("one", "two", " three");
List<String> newStrings = U.push(strings, "four", "five");
// ["one", " two", "three", " four", "five"]
String newPopString = U.pop(strings).fst();
// " three"
String newShiftString = U.shift(strings).fst();
// "one"
List<String> newUnshiftStrings = U.unshift(strings, "four", "five");
// ["four", " five", "one", " two", "three"]

Meaning of end='' in the statement print("\t",end='')?

See the documentation for the print function: print()

The content of end is printed after the thing you want to print. By default it contains a newline ("\n") but it can be changed to something else, like an empty string.

OpenJDK8 for windows

Go to this link

Download version tar.gz for windows and just extract files to the folder by your needs. On the left pane, you can select which version of openjdk to download

Tutorial: unzip as expected. You need to set system variable PATH to include your directory with openjdk so you can type java -version in console.

JDK vs OpenJDK

How to include the reference of DocumentFormat.OpenXml.dll on Mono2.10?

You should also ensure you set a reference to WindowsBase. This is required to use the SDK as it handles System.IO.Packaging (which is used for unzipping and opening the compressed .docx/.xlsx/.pptx as an OPC document).

How do I use Node.js Crypto to create a HMAC-SHA1 hash?

Gwerder's solution wont work because hash = hmac.read(); happens before the stream is done being finalized. Thus AngraX's issues. Also the hmac.write statement is un-necessary in this example.

Instead do this:

var crypto    = require('crypto');
var hmac;
var algorithm = 'sha1';
var key       = 'abcdeg';
var text      = 'I love cupcakes';
var hash;

hmac = crypto.createHmac(algorithm, key);

// readout format:
hmac.setEncoding('hex');
//or also commonly: hmac.setEncoding('base64');

// callback is attached as listener to stream's finish event:
hmac.end(text, function () {
    hash = hmac.read();
    //...do something with the hash...
});

More formally, if you wish, the line

hmac.end(text, function () {

could be written

hmac.end(text, 'utf8', function () {

because in this example text is a utf string

Assigning a variable NaN in python without numpy

Use float("nan"):

>>> float("nan")
nan

Running Tensorflow in Jupyter Notebook

It is better to create new environment with new name ($newenv):conda create -n $newenv tensorflow

Then by using anaconda navigator under environment tab you can find newenv in the middle column.

By clicking on the play button open terminal and type: activate tensorflow

Then install tensorflow inside the newenv by typing: pip install tensorflow

Now you have tensorflow inside the new environment so then install jupyter by typing: pip install jupyter notebook

Then just simply type: jupyter notebook to run the jupyter notebook.

Inside of the jupyter notebook type: import tensorflow as tf

To test the the tf you can use THIS LINK

Omitting the second expression when using the if-else shorthand

This is also an option:

x==2 && dosomething();

dosomething() will only be called if x==2 is evaluated to true. This is called Short-circuiting.

It is not commonly used in cases like this and you really shouldn't write code like this. I encourage this simpler approach:

if(x==2) dosomething();

You should write readable code at all times; if you are worried about file size, just create a minified version of it with help of one of the many JS compressors. (e.g Google's Closure Compiler)

What is the difference between a cer, pvk, and pfx file?

I actually came across something like this not too long ago... check it out over on msdn (see the first answer)

in summary:

.cer - certificate stored in the X.509 standard format. This certificate contains information about the certificate's owner... along with public and private keys.

.pvk - files are used to store private keys for code signing. You can also create a certificate based on .pvk private key file.

.pfx - stands for personal exchange format. It is used to exchange public and private objects in a single file. A pfx file can be created from .cer file. Can also be used to create a Software Publisher Certificate.

I summarized the info from the page based on the suggestion from the comments.

How do you properly use WideCharToMultiByte

You use the lpMultiByteStr [out] parameter by creating a new char array. You then pass this char array in to get it filled. You only need to initialize the length of the string + 1 so that you can have a null terminated string after the conversion.

Here are a couple of useful helper functions for you, they show the usage of all parameters.

#include <string>

std::string wstrtostr(const std::wstring &wstr)
{
    // Convert a Unicode string to an ASCII string
    std::string strTo;
    char *szTo = new char[wstr.length() + 1];
    szTo[wstr.size()] = '\0';
    WideCharToMultiByte(CP_ACP, 0, wstr.c_str(), -1, szTo, (int)wstr.length(), NULL, NULL);
    strTo = szTo;
    delete[] szTo;
    return strTo;
}

std::wstring strtowstr(const std::string &str)
{
    // Convert an ASCII string to a Unicode String
    std::wstring wstrTo;
    wchar_t *wszTo = new wchar_t[str.length() + 1];
    wszTo[str.size()] = L'\0';
    MultiByteToWideChar(CP_ACP, 0, str.c_str(), -1, wszTo, (int)str.length());
    wstrTo = wszTo;
    delete[] wszTo;
    return wstrTo;
}

--

Anytime in documentation when you see that it has a parameter which is a pointer to a type, and they tell you it is an out variable, you will want to create that type, and then pass in a pointer to it. The function will use that pointer to fill your variable.

So you can understand this better:

//pX is an out parameter, it fills your variable with 10.
void fillXWith10(int *pX)
{
  *pX = 10;
}

int main(int argc, char ** argv)
{
  int X;
  fillXWith10(&X);
  return 0;
}

Can two Java methods have same name with different return types?

Only, if they accept different parameters. If there are no parameters, then you must have different names.

int doSomething(String s);
String doSomething(int); // this is fine


int doSomething(String s);
String doSomething(String s); // this is not

Simple Android grid example using RecyclerView with GridLayoutManager (like the old GridView)

This is a simple way from XML only

spanCount for number of columns

layoutManager for making it grid or linear(Vertical or Horizontal)

<androidx.recyclerview.widget.RecyclerView
        android:id="@+id/personListRecyclerView"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layoutManager="androidx.recyclerview.widget.GridLayoutManager"
        app:spanCount="2"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

Find everything between two XML tags with RegEx

In our case, we receive an XML as a String and need to get rid of the values that have some "special" characters, like &<> etc. Basically someone can provide an XML to us in this form:

<notes>
  <note>
     <to>jenice & carl </to>
     <from>your neighbor <; </from>
  </note>
</notes>

So I need to find in that String the values jenice & carl and your neighbor <; and properly escape & and < (otherwise this is an invalid xml if you later pass it to an engine that shall rename unnamed).

Doing this with regex is a rather dumb idea to begin with, but it's cheap and easy. So the brave ones that would like to do the same thing I did, here you go:

    String xml = ...
    Pattern p = Pattern.compile("<(.+)>(?!\\R<)(.+)</(\\1)>");
    Matcher m = p.matcher(xml);
    String result = m.replaceAll(mr -> {
        if (mr.group(2).contains("&")) {
            return "<" + m.group(1) + ">" + m.group(2) + "+ some change" + "</" + m.group(3) + ">";
        }
        return "<" + m.group(1) + ">" + mr.group(2) + "</" + m.group(3) + ">";
    });

Reactjs: Unexpected token '<' Error

The issue Unexpected token '<' is because of missing the babel preset.

Solution : You have to configure your webpack configuration as follows

{
  test   : /\.jsx?$/,
  exclude: /(node_modules|bower_components)/,
  loader : 'babel',
  query  : {
    presets:[ 'react', 'es2015' ]
  }
}

here .jsx checks both .js and .jsx formats.

you can simply install the babel dependency using node as follows

npm install babel-preset-react

Thank you

Can you require two form fields to match with HTML5?

The answers that use pattern and a regex write the user's password into the input properties as plain text pattern='mypassword'. This will only be visible if developer tools are open but it still doesn't seem like a good idea.

Another issue with using pattern to check for a match is that you are likely to want to use pattern to check that the password is of the right form, e.g. mixed letters and numbers.

I also think these methods won't work well if the user switches between inputs.

Here's my solution which uses a bit more JavaScript but performs a simple equality check when either input is updated and then sets a custom HTML validity. Both inputs can still be tested for a pattern such as email format or password complexity.

For a real page you would change the input types to 'password'.

<form>
    <input type="text" id="password1" oninput="setPasswordConfirmValidity();">
    <input type="text" id="password2" oninput="setPasswordConfirmValidity();">
</form>
<script>
    function setPasswordConfirmValidity(str) {
        const password1 = document.getElementById('password1');
        const password2 = document.getElementById('password2');

        if (password1.value === password2.value) {
             password2.setCustomValidity('');
        } else {
            password2.setCustomValidity('Passwords must match');
        }
        console.log('password2 customError ', document.getElementById('password2').validity.customError);
        console.log('password2 validationMessage ', document.getElementById('password2').validationMessage);
    }
</script>

How can I calculate divide and modulo for integers in C#?

Division is performed using the / operator:

result = a / b;

Modulo division is done using the % operator:

result = a % b;

Converting characters to integers in Java

43 is the dec ascii number for the "+" symbol. That explains why you get a 43 back. http://en.wikipedia.org/wiki/ASCII

Get column index from label in a data frame

The following will do it:

which(colnames(df)=="B")

Conda activate not working?

As of conda 4.4, the command

conda activate <envname>

is the same on all platforms. The procedure to add conda to the PATH environment variable for non-Windows platforms (on Windows you should use the Anaconda Prompt), as well as the change in environment activation procedure, is detailed in the release notes for conda 4.4.0.


For conda versions older than 4.4, command is either

source activate <envname>

on Linux and macOS or

activate <envname>

on Windows. You need to remove the conda.

Chaining multiple filter() in Django, is this a bug?

Sometimes you don't want to join multiple filters together like this:

def your_dynamic_query_generator(self, event: Event):
    qs \
    .filter(shiftregistrations__event=event) \
    .filter(shiftregistrations__shifts=False)

And the following code would actually not return the correct thing.

def your_dynamic_query_generator(self, event: Event):
    return Q(shiftregistrations__event=event) & Q(shiftregistrations__shifts=False)

What you can do now is to use an annotation count-filter.

In this case we count all shifts which belongs to a certain event.

qs: EventQuerySet = qs.annotate(
    num_shifts=Count('shiftregistrations__shifts', filter=Q(shiftregistrations__event=event))
)

Afterwards you can filter by annotation.

def your_dynamic_query_generator(self):
    return Q(num_shifts=0)

This solution is also cheaper on large querysets.

Hope this helps.

How do I get a Date without time in Java?

Yo can use joda time.

private Date dateWitoutTime(Date date){
 return new LocalDate(date).toDate()
}

and you call with:

Date date = new Date();
System.out.println("Without Time = " + dateWitoutTime(date) + "/n  With time = " + date);

print highest value in dict with key

just :

 mydict = {'A':4,'B':10,'C':0,'D':87}
 max(mydict.items(), key=lambda x: x[1])

How can I restore the MySQL root user’s full privileges?

If you've deleted your root user by mistake you can do one thing:

  1. Stop MySQL service
  2. Run mysqld_safe --skip-grant-tables &
  3. Type mysql -u root -p and press enter.
  4. Enter your password
  5. At the mysql command line enter: use mysql;

Then execute this query:

insert into `user` (`Host`, `User`, `Password`, `Select_priv`, `Insert_priv`, `Update_priv`, `Delete_priv`, `Create_priv`, `Drop_priv`, `Reload_priv`, `Shutdown_priv`, `Process_priv`, `File_priv`, `Grant_priv`, `References_priv`, `Index_priv`, `Alter_priv`, `Show_db_priv`, `Super_priv`, `Create_tmp_table_priv`, `Lock_tables_priv`, `Execute_priv`, `Repl_slave_priv`, `Repl_client_priv`, `Create_view_priv`, `Show_view_priv`, `Create_routine_priv`, `Alter_routine_priv`, `Create_user_priv`, `ssl_type`, `ssl_cipher`, `x509_issuer`, `x509_subject`, `max_questions`, `max_updates`, `max_connections`, `max_user_connections`) 
values('localhost','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','','0','0','0','0');

then restart the mysqld

EDIT: October 6, 2018

In case anyone else needs this answer, I tried it today using innodb_version 5.6.36-82.0 and 10.1.24-MariaDB and it works if you REMOVE THE BACKTICKS (no single quotes either, just remove them):

insert into user (Host, User, Password, Select_priv, Insert_priv, Update_priv, Delete_priv, Create_priv, Drop_priv, Reload_priv, Shutdown_priv, Process_priv, File_priv, Grant_priv, References_priv, Index_priv, Alter_priv, Show_db_priv, Super_priv, Create_tmp_table_priv, Lock_tables_priv, Execute_priv, Repl_slave_priv, Repl_client_priv, Create_view_priv, Show_view_priv, Create_routine_priv, Alter_routine_priv, Create_user_priv, ssl_type, ssl_cipher, x509_issuer, x509_subject, max_questions, max_updates, max_connections, max_user_connections) 
values('localhost','root','','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','Y','','','','','0','0','0','0');

What is the difference between java and core java?

There are two categories as follows

  1. Core Java
  2. Java EE

Core java is a language basics. For example (Data structures, Semantics..etc) https://malalanayake.wordpress.com/category/java/data-structures/

But if you see the Java EE you can see the Sevlet, JSP, JSF all the web technologies and the patterns. https://malalanayake.wordpress.com/2014/10/10/jsp-servlet-scope-variables-and-init-parameters/

How can I print a circular structure in a JSON-like format?

I know this question is old and has lots of great answers but I post this answer because of it's new flavor (es5+)

_x000D_
_x000D_
Object.defineProperties(JSON, {_x000D_
  refStringify: {_x000D_
    value: function(obj) {_x000D_
_x000D_
      let objMap = new Map();_x000D_
      let stringified = JSON.stringify(obj,_x000D_
        function(key, value) {_x000D_
_x000D_
          // only for objects_x000D_
          if (typeof value == 'object') {_x000D_
            // If has the value then return a reference to it_x000D_
            if (objMap.has(value))_x000D_
              return objMap.get(value);_x000D_
_x000D_
            objMap.set(value, `ref${objMap.size + 1}`);_x000D_
          }_x000D_
          return value;_x000D_
        });_x000D_
      return stringified;_x000D_
    }_x000D_
  },_x000D_
  refParse: {_x000D_
    value: function(str) {_x000D_
_x000D_
      let parsed = JSON.parse(str);_x000D_
      let objMap = _createObjectMap(parsed);_x000D_
      objMap.forEach((value, key) => _replaceKeyWithObject(value, key));_x000D_
      return parsed;_x000D_
    }_x000D_
  },_x000D_
});_x000D_
_x000D_
// *************************** Example_x000D_
let a = {_x000D_
  b: 32,_x000D_
  c: {_x000D_
    get a() {_x000D_
        return a;_x000D_
      },_x000D_
      get c() {_x000D_
        return a.c;_x000D_
      }_x000D_
  }_x000D_
};_x000D_
let stringified = JSON.refStringify(a);_x000D_
let parsed = JSON.refParse(stringified, 2);_x000D_
console.log(parsed, JSON.refStringify(parsed));_x000D_
// *************************** /Example_x000D_
_x000D_
// *************************** Helper_x000D_
function _createObjectMap(obj) {_x000D_
_x000D_
  let objMap = new Map();_x000D_
  JSON.stringify(obj, (key, value) => {_x000D_
    if (typeof value == 'object') {_x000D_
      if (objMap.has(value))_x000D_
        return objMap.get(value);_x000D_
      objMap.set(value, `ref${objMap.size + 1}`);_x000D_
_x000D_
    }_x000D_
    return value;_x000D_
  });_x000D_
  return objMap;_x000D_
}_x000D_
_x000D_
function _replaceKeyWithObject(key, obj, replaceWithObject = obj) {_x000D_
_x000D_
  Object.keys(obj).forEach(k => {_x000D_
_x000D_
    let val = obj[k];_x000D_
    if (val == key)_x000D_
      return (obj[k] = replaceWithObject);_x000D_
    if (typeof val == 'object' && val != replaceWithObject)_x000D_
      _replaceKeyWithObject(key, val, replaceWithObject);_x000D_
  });_x000D_
}
_x000D_
_x000D_
_x000D_

How to fix the Eclipse executable launcher was unable to locate its companion shared library for windows 7?

This is an issue with the 64 bit version of Kepler and windows7 in my case. I downloaded the 32 bit and it worked immediately.

How to get main div container to align to centre?

The basic principle of centering a page is to have a body CSS and main_container CSS. It should look something like this:

body {
     margin: 0;
     padding: 0;
     text-align: center;
}
#main_container {
     margin: 0 auto;
     text-align: left;
}

"Mixed content blocked" when running an HTTP AJAX operation in an HTTPS page

If you are just visiting a webpage that you trust and you want to move forward fast, just:

1- Click the shield icon in the far right of the address bar.

Allow mixed content in Google Chrome

2- In the pop-up window, click "Load anyway" or "Load unsafe script" (depending on your Chrome version).


If you want to set your Chrome browser to ALWAYS(in all webpages) allow mixed content:

1- In an open Chrome browser, press Ctrl+Shift+Q on your keyboard to force close Chrome. Chrome must be fully closed before the next steps.

2- Right-click the Google Chrome desktop icon (or Start Menu link). Select Properties.

3- At the end of the existing information in the Target field, add: " --allow-running-insecure-content" (There is a space before the first dash.)

4- Click OK.

5- Open Chrome and try to launch the content that was blocked earlier. It should work now.

ggplot2, change title size

+ theme(plot.title = element_text(size=22))

Here is the full set of things you can change in element_text:

element_text(family = NULL, face = NULL, colour = NULL, size = NULL,
  hjust = NULL, vjust = NULL, angle = NULL, lineheight = NULL,
  color = NULL)

How to read a Parquet file into Pandas DataFrame?

Update: since the time I answered this there has been a lot of work on this look at Apache Arrow for a better read and write of parquet. Also: http://wesmckinney.com/blog/python-parquet-multithreading/

There is a python parquet reader that works relatively well: https://github.com/jcrobak/parquet-python

It will create python objects and then you will have to move them to a Pandas DataFrame so the process will be slower than pd.read_csv for example.

Using scp to copy a file to Amazon EC2 instance?

Check the permissions on the .pem file...openssh usually doesn't like world-readable private keys, and will fail (iir, scp doesn't do a great job of providing this feedback to the user).

Can you simply ssh with that key to your AWS host?

How to sort a collection by date in MongoDB?

Sushant Gupta's answers are a tad bit outdated and don't work anymore.

The following snippet should be like this now :

collection.find({}, {"sort" : ['datefield', 'asc']} ).toArray(function(err,docs) {});

Is there a way to suppress JSHint warning for one given line?

Yes, there is a way. Two in fact. In October 2013 jshint added a way to ignore blocks of code like this:

// Code here will be linted with JSHint.
/* jshint ignore:start */
// Code here will be ignored by JSHint.
/* jshint ignore:end */
// Code here will be linted with JSHint.

You can also ignore a single line with a trailing comment like this:

ignoreThis(); // jshint ignore:line

select unique rows based on single distinct column

If you are using MySql 5.7 or later, according to these links (MySql Official, SO QA), we can select one record per group by with out the need of any aggregate functions.

So the query can be simplified to this.

select * from comments_table group by commentname;

Try out the query in action here

What's the difference between using "let" and "var"?

What's the difference between let and var?

  • A variable defined using a var statement is known throughout the function it is defined in, from the start of the function. (*)
  • A variable defined using a let statement is only known in the block it is defined in, from the moment it is defined onward. (**)

To understand the difference, consider the following code:

// i IS NOT known here
// j IS NOT known here
// k IS known here, but undefined
// l IS NOT known here

function loop(arr) {
    // i IS known here, but undefined
    // j IS NOT known here
    // k IS known here, but has a value only the second time loop is called
    // l IS NOT known here

    for( var i = 0; i < arr.length; i++ ) {
        // i IS known here, and has a value
        // j IS NOT known here
        // k IS known here, but has a value only the second time loop is called
        // l IS NOT known here
    };

    // i IS known here, and has a value
    // j IS NOT known here
    // k IS known here, but has a value only the second time loop is called
    // l IS NOT known here

    for( let j = 0; j < arr.length; j++ ) {
        // i IS known here, and has a value
        // j IS known here, and has a value
        // k IS known here, but has a value only the second time loop is called
        // l IS NOT known here
    };

    // i IS known here, and has a value
    // j IS NOT known here
    // k IS known here, but has a value only the second time loop is called
    // l IS NOT known here
}

loop([1,2,3,4]);

for( var k = 0; k < arr.length; k++ ) {
    // i IS NOT known here
    // j IS NOT known here
    // k IS known here, and has a value
    // l IS NOT known here
};

for( let l = 0; l < arr.length; l++ ) {
    // i IS NOT known here
    // j IS NOT known here
    // k IS known here, and has a value
    // l IS known here, and has a value
};

loop([1,2,3,4]);

// i IS NOT known here
// j IS NOT known here
// k IS known here, and has a value
// l IS NOT known here

Here, we can see that our variable j is only known in the first for loop, but not before and after. Yet, our variable i is known in the entire function.

Also, consider that block scoped variables are not known before they are declared because they are not hoisted. You're also not allowed to redeclare the same block scoped variable within the same block. This makes block scoped variables less error prone than globally or functionally scoped variables, which are hoisted and which do not produce any errors in case of multiple declarations.


Is it safe to use let today?

Some people would argue that in the future we'll ONLY use let statements and that var statements will become obsolete. JavaScript guru Kyle Simpson wrote a very elaborate article on why he believes that won't be the case.

Today, however, that is definitely not the case. In fact, we need actually to ask ourselves whether it's safe to use the let statement. The answer to that question depends on your environment:

  • If you're writing server-side JavaScript code (Node.js), you can safely use the let statement.

  • If you're writing client-side JavaScript code and use a browser based transpiler (like Traceur or babel-standalone), you can safely use the let statement, however your code is likely to be anything but optimal with respect to performance.

  • If you're writing client-side JavaScript code and use a Node based transpiler (like the traceur shell script or Babel), you can safely use the let statement. And because your browser will only know about the transpiled code, performance drawbacks should be limited.

  • If you're writing client-side JavaScript code and don't use a transpiler, you need to consider browser support.

    There are still some browsers that don't support let at all :

enter image description here


How to keep track of browser support

For an up-to-date overview of which browsers support the let statement at the time of your reading this answer, see this Can I Use page.


(*) Globally and functionally scoped variables can be initialized and used before they are declared because JavaScript variables are hoisted. This means that declarations are always much to the top of the scope.

(**) Block scoped variables are not hoisted

How can I avoid running ActiveRecord callbacks?

Something that should work with all versions of ActiveRecord without depending on options or activerecord methods that may or may not exist.

module PlainModel
  def self.included(base)
    plainclass = Class.new(ActiveRecord::Base) do
      self.table_name = base.table_name
    end
    base.const_set(:Plain, plainclass)
  end
end


# usage
class User < ActiveRecord::Base
  include PlainModel

  validates_presence_of :email
end

User.create(email: "")        # fail due to validation
User::Plain.create(email: "") # success. no validation, no callbacks

user = User::Plain.find(1)
user.email = ""
user.save

TLDR: use a "different activerecord model" over the same table

How to check if two arrays are equal with JavaScript?

For primitive values like numbers and strings this is an easy solution:

a = [1,2,3]

b = [3,2,1]

a.sort().toString() == b.sort().toString() 

The call to sort() will ensure that the order of the elements does not matter. The toString() call will create a string with the values comma separated so both strings can be tested for equality.

Custom designing EditText

enter image description here

For EditText in image above, You have to create two xml files in res-->drawable folder. First will be "bg_edittext_focused.xml" paste the lines of code in it

<?xml version="1.0" encoding="utf-8"?>
    <shape xmlns:android="http://schemas.android.com/apk/res/android" >
        <solid android:color="#FFFFFF" />
        <stroke
            android:width="2dip"
            android:color="#F6F6F6" />
        <corners android:radius="2dip" />
        <padding
            android:bottom="7dip"
            android:left="7dip"
            android:right="7dip"
            android:top="7dip" />
    </shape>

Second file will be "bg_edittext_normal.xml" paste the lines of code in it

<?xml version="1.0" encoding="utf-8"?>
    <shape xmlns:android="http://schemas.android.com/apk/res/android" >
        <solid android:color="#F6F6F6" />
        <stroke
            android:width="2dip"
            android:color="#F6F6F6" />
        <corners android:radius="2dip" />
        <padding
            android:bottom="7dip"
            android:left="7dip"
            android:right="7dip"
            android:top="7dip" />
    </shape>

In res-->drawable folder create another xml file with name "bg_edittext.xml" that will call above mentioned code. paste the following lines of code below in bg_edittext.xml

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/bg_edittext_focused" android:state_focused="true"/>
    <item android:drawable="@drawable/bg_edittext_normal"/>
</selector>

Finally in res-->layout-->example.xml file in your case wherever you created your editText you'll call bg_edittext.xml as background

   <EditText
    :::::
    :::::  
    android:background="@drawable/bg_edittext"
    :::::
    :::::
    />

When should we call System.exit in Java

System.exit is needed

  • when you want to return a non-0 error code
  • when you want to exit your program from somewhere that isn't main()

In your case, it does the exact same thing as the simple return-from-main.

How to change the icon of an Android app in Eclipse?

You can find an easy guide here

The step are 2: - Copy the icon in the correct folder/folders - Change the AndroidManifest.xml

How to download file from database/folder using php

butangDonload.php

$file = "Bang.png"; //Let say If I put the file name Bang.png
$_SESSION['name']=$file;    

Try this,

<?php

$name=$_SESSION['name'];
download($name);

function download($name){
$file = $nama_fail;
?>

Uncaught TypeError: data.push is not a function

I think you set it as

var data = []; 

but after some time you made it like:

data = 'some thing which is not an array'; 

then data.push('') will not work as it is not an array anymore.

How do I install PIL/Pillow for Python 3.6?

You can download the wheel corresponding to your configuration here ("Pillow-4.1.1-cp36-cp36m-win_amd64.whl" in your case) and install it with:

pip install some-package.whl

If you have problem to install the wheel read this answer

Pandas sort by group aggregate and column

Here's a more concise approach...

df['a_bsum'] = df.groupby('A')['B'].transform(sum)
df.sort(['a_bsum','C'], ascending=[True, False]).drop('a_bsum', axis=1)

The first line adds a column to the data frame with the groupwise sum. The second line performs the sort and then removes the extra column.

Result:

    A       B           C
5   baz     -2.301539   True
2   baz     -0.528172   False
1   bar     -0.611756   True
4   bar      0.865408   False
3   foo     -1.072969   True
0   foo      1.624345   False

NOTE: sort is deprecated, use sort_values instead

Simple way to measure cell execution time in ipython notebook

Sometimes the formatting is different in a cell when using print(res), but jupyter/ipython comes with a display. See an example of the formatting difference using pandas below.

%%time
import pandas as pd 
from IPython.display import display

df = pd.DataFrame({"col0":{"a":0,"b":0}
              ,"col1":{"a":1,"b":1}
              ,"col2":{"a":2,"b":2}
             })

#compare the following
print(df)
display(df)

The display statement can preserve the formatting. screenshot

Is it possible to modify a string of char in C?

char *a = "stack overflow";
char *b = "new string, it's real";
int d = strlen(a);

b = malloc(d * sizeof(char));
b = strcpy(b,a);
printf("%s %s\n", a, b);

Is there a way to return a list of all the image file names from a folder using only Javascript?

This will list all jpg files in the folder you define under url: and append them to a div as a paragraph. Can do it with ul li as well.

$.ajax({
  url: "YOUR FOLDER",
  success: function(data){
     $(data).find("a:contains(.jpg)").each(function(){
        // will loop through 
        var images = $(this).attr("href");

        $('<p></p>').html(images).appendTo('a div of your choice')

     });
  }
});

C# - Print dictionary

More cleaner way using LINQ

var lines = dictionary.Select(kvp => kvp.Key + ": " + kvp.Value.ToString());
textBox3.Text = string.Join(Environment.NewLine, lines);

How do C++ class members get initialized if I don't do it explicitly?

Uninitialized non-static members will contain random data. Actually, they will just have the value of the memory location they are assigned to.

Of course for object parameters (like string) the object's constructor could do a default initialization.

In your example:

int *ptr; // will point to a random memory location
string name; // empty string (due to string's default costructor)
string *pname; // will point to a random memory location
string &rname; // it would't compile
const string &crname; // it would't compile
int age; // random value

Use SQL Server Management Studio to connect remotely to an SQL Server Express instance hosted on an Azure Virtual Machine

Here are the three web pages on which we found the answer. The most difficult part was setting up static ports for SQLEXPRESS.

Provisioning a SQL Server Virtual Machine on Windows Azure. These initial instructions provided 25% of the answer.

How to Troubleshoot Connecting to the SQL Server Database Engine. Reading this carefully provided another 50% of the answer.

How to configure SQL server to listen on different ports on different IP addresses?. This enabled setting up static ports for named instances (eg SQLEXPRESS.) It took us the final 25% of the way to the answer.

Remove git mapping in Visual Studio 2015

Tools -> Options -> Source Control -> Current Source Control Plug-in: None

addEventListener for keydown on Canvas

encapsulate all of your js code within a window.onload function. I had a similar issue. Everything is loaded asynchronously in javascript so some parts load quicker than others, including your browser. Putting all of your code inside the onload function will ensure everything your code will need from the browser will be ready to use before attempting to execute.

kill -3 to get java thread dump

In the same location where the JVM's stdout is placed. If you have a Tomcat server, this will be the catalina_(date).out file.

Adding open/closed icon to Twitter Bootstrap collapsibles (accordions)

Shortest possible answer.

HTML

<a data-toggle="collapse" data-parent="#panel-quote-group" href="#collapseQuote">
    <span class="toggle-icon glyphicon glyphicon-collapse-up"></span>
</a>

JS:

<script type="text/javascript">
 $(function () {
     $('a[data-toggle="collapse"]').click(function () {
     $(this).find('span.toggle-icon').toggleClass('glyphicon-collapse-up glyphicon-collapse-down');
     })
 })
 </script>

And of course, you can use anything for a selector instead of anchor tag a and you can also use specific selector instead of this if your icon lies outside your clicked element.

Is there an advantage to use a Synchronized Method instead of a Synchronized Block?

Often using a lock on a method level is too rude. Why lock up a piece of code that does not access any shared resources by locking up an entire method. Since each object has a lock, you can create dummy objects to implement block level synchronization. The block level is more efficient because it does not lock the whole method.

Here some example

Method Level

class MethodLevel {

  //shared among threads
SharedResource x, y ;

public void synchronized method1() {
   //multiple threads can't access
}
public void synchronized method2() {
  //multiple threads can't access
}

 public void method3() {
  //not synchronized
  //multiple threads can access
 }
}

Block Level

class BlockLevel {
  //shared among threads
  SharedResource x, y ;

  //dummy objects for locking
  Object xLock = new Object();
  Object yLock = new Object();

    public void method1() {
     synchronized(xLock){
    //access x here. thread safe
    }

    //do something here but don't use SharedResource x, y
    // because will not be thread-safe
     synchronized(xLock) {
       synchronized(yLock) {
      //access x,y here. thread safe
      }
     }

     //do something here but don't use SharedResource x, y
     //because will not be thread-safe
    }//end of method1
 }

[Edit]

For Collection like Vector and Hashtable they are synchronized when ArrayList or HashMap are not and you need set synchronized keyword or invoke Collections synchronized method:

Map myMap = Collections.synchronizedMap (myMap); // single lock for the entire map
List myList = Collections.synchronizedList (myList); // single lock for the entire list

Convert an integer to an array of digits

It would be much simpler to use the String.split method:

public static void fn(int guess) {
    String[] sNums = Integer.toString(guess).split("");
    for (String s : nums) {
    ...

Check for null variable in Windows batch

To test for the existence of a command line paramater, use empty brackets:

IF [%1]==[] echo Value Missing

or

IF [%1] EQU [] echo Value Missing

The SS64 page on IF will help you here. Under "Does %1 exist?".

You can't set a positional parameter, so what you should do is do something like

SET MYVAR=%1

You can then re-set MYVAR based on its contents.

How to convert a string to ASCII

Use Convert.ToInt32() for conversion. You can have a look at How to convert string to ASCII value in C# and ASCII values.

How to declare a static const char* in your header file?

With C++11 you can use the constexpr keyword and write in your header:

private:
    static constexpr const char* SOMETHING = "something";


Notes:

  • constexpr makes SOMETHING a constant pointer so you cannot write

    SOMETHING = "something different";
    

    later on.

  • Depending on your compiler, you might also need to write an explicit definition in the .cpp file:

    constexpr const char* MyClass::SOMETHING;
    

Print all but the first three columns

I can't believe nobody offered plain shell:

while read -r a b c d; do echo "$d"; done < file

Operation is not valid due to the current state of the object, when I select a dropdown list

I know an answer has already been accepted for this problem but someone asked in the comments if there was a solution that could be done outside the web.config. I had a ListView producing the exact same error and setting EnableViewState to false resolved this problem for me.

jQuery override default validation error message display (Css) Popup/Tooltip like

You can use the errorPlacement option to override the error message display with little css. Because css on its own will not be enough to produce the effect you need.

$(document).ready(function(){
    $("#myForm").validate({
        rules: {
            "elem.1": {
                required: true,
                digits: true
            },
            "elem.2": {
                required: true
            }
        },
        errorElement: "div",
        wrapper: "div",  // a wrapper around the error message
        errorPlacement: function(error, element) {
            offset = element.offset();
            error.insertBefore(element)
            error.addClass('message');  // add a class to the wrapper
            error.css('position', 'absolute');
            error.css('left', offset.left + element.outerWidth());
            error.css('top', offset.top);
        }

    });
});

You can play with the left and top css attributes to show the error message on top, left, right or bottom of the element. For example to show the error on the top:

    errorPlacement: function(error, element) {
        element.before(error);
        offset = element.offset();
        error.css('left', offset.left);
        error.css('top', offset.top - element.outerHeight());
    }

And so on. You can refer to jQuery documentation about css for more options.

Here is the css I used. The result looks exactly like the one you want. With as little CSS as possible:

div.message{
    background: transparent url(msg_arrow.gif) no-repeat scroll left center;
    padding-left: 7px;
}

div.error{
    background-color:#F3E6E6;
    border-color: #924949;
    border-style: solid solid solid none;
    border-width: 2px;
    padding: 5px;
}

And here is the background image you need:

alt text
(source: scriptiny.com)

If you want the error message to be displayed after a group of options or fields. Then group all those elements inside one container a 'div' or a 'fieldset'. Add a special class to all of them 'group' for example. And add the following to the begining of the errorPlacement function:

errorPlacement: function(error, element) {
    if (element.hasClass('group')){
        element = element.parent();
    }
    ...// continue as previously explained

If you only want to handle specific cases you can use attr instead:

if (element.attr('type') == 'radio'){
    element = element.parent();
}

That should be enough for the error message to be displayed next to the parent element.

You may need to change the width of the parent element to be less than 100%.


I've tried your code and it is working perfectly fine for me. Here is a preview: alt text

I just made a very small adjustment to the message padding to make it fit in the line:

div.error {
    padding: 2px 5px;
}

You can change those numbers to increase/decrease the padding on top/bottom or left/right. You can also add a height and width to the error message. If you are still having issues, try to replace the span with a div

<div class="group">
<input type="radio" class="checkbox" value="P" id="radio_P" name="radio_group_name"/>
<label for="radio_P">P</label>
<input type="radio" class="checkbox" value="S" id="radio_S" name="radio_group_name"/>
<label for="radio_S">S</label>
</div>

And then give the container a width (this is very important)

div.group {
    width: 50px; /* or any other value */
}

About the blank page. As I said I tried your code and it is working for me. It might be something else in your code that is causing the issue.

Oracle database: How to read a BLOB?

What client do you use? .Net, Java, Ruby, SQLPLUS, SQL DEVELOPER? Where did you write that simple select statement?

And why do you want to read the content of the blob, a blob contains binary data so that data is unreadable. You should use a clob instead of a blob if you want to store text instead of binary content.

I suggest that you download SQL DEVELOPER: http://www.oracle.com/technetwork/developer-tools/sql-developer/overview/index.html . With SQL DEVELOPER you can see the content.

NULL vs nullptr (Why was it replaced?)

Here is Bjarne Stroustrup's wordings,

In C++, the definition of NULL is 0, so there is only an aesthetic difference. I prefer to avoid macros, so I use 0. Another problem with NULL is that people sometimes mistakenly believe that it is different from 0 and/or not an integer. In pre-standard code, NULL was/is sometimes defined to something unsuitable and therefore had/has to be avoided. That's less common these days.

If you have to name the null pointer, call it nullptr; that's what it's called in C++11. Then, "nullptr" will be a keyword.

milliseconds to days

If you don't have another time interval bigger than days:

int days = (int) (milliseconds / (1000*60*60*24));

If you have weeks too:

int days = (int) ((milliseconds / (1000*60*60*24)) % 7);
int weeks = (int) (milliseconds / (1000*60*60*24*7));

It's probably best to avoid using months and years if possible, as they don't have a well-defined fixed length. Strictly speaking neither do days: daylight saving means that days can have a length that is not 24 hours.

How do I merge a git tag onto a branch

You mean this?

git checkout destination_branch
git merge tag_name

Get Maven artifact version at runtime

I am using maven-assembly-plugin for my maven packaging. The usage of Apache Maven Archiver in Joachim Sauer's answer could also work:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-assembly-plugin</artifactId>
    <configuration>
        <descriptorRefs>
            <descriptorRef>jar-with-dependencies</descriptorRef>
        </descriptorRefs>
        <archive>
            <manifest>
                <addDefaultImplementationEntries>true</addDefaultImplementationEntries>
                <addDefaultSpecificationEntries>true</addDefaultSpecificationEntries>
            </manifest>
        </archive>
    </configuration>
    <executions>
        <execution .../>
    </executions>
</plugin>

Because archiever is one of maven shared components, it could be used by multiple maven building plugins, which could also have conflict if two or more plugins introduced, including archive configuration inside.

How to downgrade Xcode to previous version?

When you log in to your developer account, you can find a link at the bottom of the download section for Xcode that says "Looking for an older version of Xcode?". In there you can find download links to older versions of Xcode and other developer tools

Where is the correct location to put Log4j.properties in an Eclipse project?

Add the log4j.properties file to the runtime class path of the project. Some people add this to the root of the source tree (so that it gets copied to the root of the compiled classes).

Edit: If your project is a maven project, you can put the log4j.properties in the src/main/resources folder (and the src/test/resources for your unit tests).

If you have multiple environments (for example development and production), want different logging for each environment, and want to deploy the same jar (or war, or ear) file to each environment (as in one build for all environments) then store the log4j.properties file outside of the jar file and put it in the class path for each environment (configurable by environment). Historically, I would include some known directory in each environment in the classpath and deploy environment specific stuff there. For example, ~tomcat_user/localclasspath where ~tomcat_user is the home directory of the user that will be running the tomcat instance to which my war file will be deployed.

How to change the new TabLayout indicator color and height

from xml :

app:tabIndicatorColor="#fff"

from java :

tabLayout.setSelectedTabIndicatorColor(Color.parseColor("#FFFFFF"));
tabLayout.setSelectedTabIndicatorHeight((int) (2 * getResources().getDisplayMetrics().density));

JSON forEach get Key and Value

Another easy way to do this is by using the following syntax to iterate through the object, keeping access to the key and value:

for(var key in object){
  console.log(key + ' - ' + object[key])
}

so for yours:

for(var key in obj){
  console.log(key + ' - ' + obj[key])
}

What should I do when 'svn cleanup' fails?

When I face this issue with TortoiseSVN (Windows), I go to Cygwin and run the 'svn cleanup' from there; it cleans up correctly for me, after which everything works from TortoiseSVN.

RecyclerView expand/collapse items

I am surprised that there's no concise answer yet, although such an expand/collapse animation is very easy to achieve with just 2 lines of code:

(recycler.itemAnimator as SimpleItemAnimator).supportsChangeAnimations = false // called once

together with

notifyItemChanged(position) // in adapter, whenever a child view in item's recycler gets hidden/shown

So for me, the explanations in the link below were really useful: https://medium.com/@nikola.jakshic/how-to-expand-collapse-items-in-recyclerview-49a648a403a6

XPath: Get parent node from child node

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

How could I get its parent? Result should be the store node.

Use a predicate rather than the parent:: or ancestor:: axis

Most answers here select the title and then traverse up to the targeted parent or ancestor (store) element. A simpler, direct approach is to select parent or ancestor element directly in the first place, obviating the need to traverse to a parent:: or ancestor:: axes:

//*[book/title = "50"]

Should the intervening elements vary in name:

//*[*/title = "50"]

Or, in name and depth:

//*[.//title = "50"]

CGRectMake, CGPointMake, CGSizeMake, CGRectZero, CGPointZero is unavailable in Swift

If you want to use them as in swift 2, you can use these funcs:

For CGRectMake:

func CGRectMake(_ x: CGFloat, _ y: CGFloat, _ width: CGFloat, _ height: CGFloat) -> CGRect {
    return CGRect(x: x, y: y, width: width, height: height)
}

For CGPointMake:

func CGPointMake(_ x: CGFloat, _ y: CGFloat) -> CGPoint {
    return CGPoint(x: x, y: y)
}

For CGSizeMake:

func CGSizeMake(_ width: CGFloat, _ height: CGFloat) -> CGSize {
    return CGSize(width: width, height: height)
}

Just put them outside any class and it should work. (Works for me at least)

How to get database structure in MySQL via query

I think that what you're after is DESCRIBE

DESCRIBE table;

You can also use SHOW TABLES

SHOW TABLES;

to get a list of the tables in your database.

How to paginate with Mongoose in Node.js?

Simple and powerful pagination solution

async getNextDocs(no_of_docs_required: number, last_doc_id?: string) {
    let docs

    if (!last_doc_id) {
        // get first 5 docs
        docs = await MySchema.find().sort({ _id: -1 }).limit(no_of_docs_required)
    }
    else {
        // get next 5 docs according to that last document id
        docs = await MySchema.find({_id: {$lt: last_doc_id}})
                                    .sort({ _id: -1 }).limit(no_of_docs_required)
    }
    return docs
}

last_doc_id: the last document id that you get

no_of_docs_required: the number of docs that you want to fetch i.e. 5, 10, 50 etc.

  1. If you don't provide the last_doc_id to the method, you'll get i.e. 5 latest docs
  2. If you've provided the last_doc_id then you'll get the next i.e. 5 documents.

How to avoid "RuntimeError: dictionary changed size during iteration" error?

In Python 3.x and 2.x you can use use list to force a copy of the keys to be made:

for i in list(d):

In Python 2.x calling keys made a copy of the keys that you could iterate over while modifying the dict:

for i in d.keys():

But note that in Python 3.x this second method doesn't help with your error because keys returns an a view object instead of copynig the keys into a list.

URL for public Amazon S3 bucket

The URL structure you're referring to is called the REST endpoint, as opposed to the Web Site Endpoint.


Note: Since this answer was originally written, S3 has rolled out dualstack support on REST endpoints, using new hostnames, while leaving the existing hostnames in place. This is now integrated into the information provided, below.


If your bucket is really in the us-east-1 region of AWS -- which the S3 documentation formerly referred to as the "US Standard" region, but was subsequently officially renamed to the "U.S. East (N. Virginia) Region" -- then http://s3-us-east-1.amazonaws.com/bucket/ is not the correct form for that endpoint, even though it looks like it should be. The correct format for that region is either http://s3.amazonaws.com/bucket/ or http://s3-external-1.amazonaws.com/bucket/

The format you're using is applicable to all the other S3 regions, but not US Standard US East (N. Virginia) [us-east-1].

S3 now also has dual-stack endpoint hostnames for the REST endpoints, and unlike the original endpoint hostnames, the names of these have a consistent format across regions, for example s3.dualstack.us-east-1.amazonaws.com. These endpoints support both IPv4 and IPv6 connectivity and DNS resolution, but are otherwise functionally equivalent to the existing REST endpoints.

If your permissions and configuration are set up such that the web site endpoint works, then the REST endpoint should work, too.

However... the two endpoints do not offer the same functionality.

Roughly speaking, the REST endpoint is better-suited for machine access and the web site endpoint is better suited for human access, since the web site endpoint offers friendly error messages, index documents, and redirects, while the REST endpoint doesn't. On the other hand, the REST endpoint offers HTTPS and support for signed URLs, while the web site endpoint doesn't.

Choose the correct type of endpoint (REST or web site) for your application:

http://docs.aws.amazon.com/AmazonS3/latest/dev/WebsiteEndpoints.html#WebsiteRestEndpointDiff


¹ s3-external-1.amazonaws.com has been referred to as the "Northern Virginia endpoint," in contrast to the "Global endpoint" s3.amazonaws.com. It was unofficially possible to get read-after-write consistency on new objects in this region if the "s3-external-1" hostname was used, because this would send you to a subset of possible physical endpoints that could provide that functionality. This behavior is now officially supported on this endpoint, so this is probably the better choice in many applications. Previously, s3-external-2 had been referred to as the "Pacific Northwest endpoint" for US-Standard, though it is now a CNAME in DNS for s3-external-1 so s3-external-2 appears to have no purpose except backwards-compatibility.

How to update a git clone --mirror?

Regarding commits, refs, branches and "et cetera", Magnus answer just works (git remote update).

But unfortunately there is no way to clone / mirror / update the hooks, as I wanted...

I have found this very interesting thread about cloning/mirroring the hooks:

http://kerneltrap.org/mailarchive/git/2007/8/28/256180/thread

I learned:

  • The hooks are not considered part of the repository contents.

  • There is more data, like the .git/description folder, which does not get cloned, just as the hooks.

  • The default hooks that appear in the hooks dir comes from the TEMPLATE_DIR

  • There is this interesting template feature on git.

So, I may either ignore this "clone the hooks thing", or go for a rsync strategy, given the purposes of my mirror (backup + source for other clones, only).

Well... I will just forget about hooks cloning, and stick to the git remote update way.

  • Sehe has just pointed out that not only "hooks" aren't managed by the clone / update process, but also stashes, rerere, etc... So, for a strict backup, rsync or equivalent would really be the way to go. As this is not really necessary in my case (I can afford not having hooks, stashes, and so on), like I said, I will stick to the remote update.

Thanks! Improved a bit of my own "git-fu"... :-)

Listen to port via a Java socket

Try this piece of code, rather than ObjectInputStream.

BufferedReader in = new BufferedReader (new InputStreamReader (socket.getInputStream ()));
while (true)
{
    String cominginText = "";
    try
    {
        cominginText = in.readLine ();
        System.out.println (cominginText);
    }
    catch (IOException e)
    {
        //error ("System: " + "Connection to server lost!");
        System.exit (1);
        break;
    }
}

Enum "Inheritance"

another possible solution:

public enum @base
{
    x,
    y,
    z
}

public enum consume
{
    x = @base.x,
    y = @base.y,
    z = @base.z,

    a,b,c
}

// TODO: Add a unit-test to check that if @base and consume are aligned

HTH

Can I clear cell contents without changing styling?

you can use ClearContents. ex,

Range("X").Cells.ClearContents

How do I copy a 2 Dimensional array in Java?

public  static byte[][] arrayCopy(byte[][] arr){
    if(arr!=null){
        int[][] arrCopy = new int[arr.length][] ;
        System.arraycopy(arr, 0, arrCopy, 0, arr.length);
        return arrCopy;
    }else { return new int[][]{};}
}

How do you remove the title text from the Android ActionBar?

getSupportActionBar().setDisplayShowTitleEnabled(false);
    getSupportActionBar().hide();

hope this will help

How to store Java Date to Mysql datetime with JPA

I still prefer the method in one line

new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(Calendar.getInstance().getTime())

Powershell: How can I stop errors from being displayed in a script?

I had a similar problem when trying to resolve host names using [system.net.dns]. If the IP wasn't resolved .Net threw a terminating error. To prevent the terminating error and still retain control of the output, I created a function using TRAP.

E.G.

Function Get-IP 
{PARAM   ([string]$HostName="")
PROCESS {TRAP 
             {"" ;continue} 
             [system.net.dns]::gethostaddresses($HostName)
        }
}

How to Use UTF-8 Collation in SQL Server database?

No! It's not a joke.

Take a look here: http://msdn.microsoft.com/en-us/library/ms186939.aspx

Character data types that are either fixed-length, nchar, or variable-length, nvarchar, Unicode data and use the UNICODE UCS-2 character set.

And also here: http://en.wikipedia.org/wiki/UTF-16

The older UCS-2 (2-byte Universal Character Set) is a similar character encoding that was superseded by UTF-16 in version 2.0 of the Unicode standard in July 1996.

How to delete a record in Django models?

Extending the top voted comment.

Note that you should pass request as a parameter to your delete function in your views. An example would be like:

from django.shortcuts import redirect


def delete(request, id):
YourModelName.objects.filter(id=id).delete()

return redirect('url_name')

How to git reset --hard a subdirectory?

According to Git developer Duy Nguyen who kindly implemented the feature and a compatibility switch, the following works as expected as of Git 1.8.3:

git checkout -- a

(where a is the directory you want to hard-reset). The original behavior can be accessed via

git checkout --ignore-skip-worktree-bits -- a

How to remove a virtualenv created by "pipenv run"

You can run the pipenv command with the --rm option as in:

pipenv --rm

This will remove the virtualenv created for you under ~/.virtualenvs

See https://pipenv.kennethreitz.org/en/latest/cli/#cmdoption-pipenv-rm

Why use multiple columns as primary keys (composite primary key)

The W3Schools example isn't saying when you should use compound primary keys, and is only giving example syntax using the same example table as for other keys.

Their choice of example is perhaps misleading you by combining a meaningless key (P_Id) and a natural key (LastName). This odd choice of primary key says that the following rows are valid according to the schema and are necessary to uniquely identify a student. Intuitively this doesn't make sense.

1234     Jobs
1234     Gates

Further Reading: The great primary-key debate or just Google meaningless primary keys or even peruse this SO question

FWIW - My 2 cents is to avoid multi-column primary keys and use a single generated id field (surrogate key) as the primary key and add additional (unique) constraints where necessary.

putting datepicker() on dynamically created elements - JQuery/JQueryUI

here is the trick:

$('body').on('focus',".datepicker_recurring_start", function(){
    $(this).datepicker();
});?

DEMO

The $('...selector..').on('..event..', '...another-selector...', ...callback...); syntax means:
Add a listener to ...selector.. (the body in our example) for the event ..event.. ('focus' in our example). For all the descendants of the matching nodes that matches the selector ...another-selector... (.datepicker_recurring_start in our example) , apply the event handler ...callback... (the inline function in our example)

See http://api.jquery.com/on/ and especially the section about "delegated events"

Importing PNG files into Numpy?

If you are loading images, you are likely going to be working with one or both of matplotlib and opencv to manipulate and view the images.

For this reason, I tend to use their image readers and append those to lists, from which I make a NumPy array.

import os
import matplotlib.pyplot as plt
import cv2
import numpy as np

# Get the file paths
im_files = os.listdir('path/to/files/')

# imagine we only want to load PNG files (or JPEG or whatever...)
EXTENSION = '.png'

# Load using matplotlib
images_plt = [plt.imread(f) for f in im_files if f.endswith(EXTENSION)]
# convert your lists into a numpy array of size (N, H, W, C)
images = np.array(images_plt)

# Load using opencv
images_cv = [cv2.imread(f) for f in im_files if f.endswith(EXTENSION)]
# convert your lists into a numpy array of size (N, C, H, W)
images = np.array(images_cv)

The only difference to be aware of is the following:

  • opencv loads channels first
  • matplotlib loads channels last.

So a single image that is 256*256 in size would produce matrices of size (3, 256, 256) with opencv and (256, 256, 3) using matplotlib.

How can I change a button's color on hover?

a.button a:hover means "a link that's being hovered over that is a child of a link with the class button".

Go instead for a.button:hover.

Folder is locked and I can't unlock it

Using svn command line to unlock the local folders, just use svn cleanup.

Before:

# svn commit -m "fixing #1234"

commit

# svn st

before

# svn cleanup

After:

# svn st

after

# svn commit -m "fixing #1234"

after2

Java IOException "Too many open files"

Recently, I had a program batch processing files, I have certainly closed each file in the loop, but the error still there.

And later, I resolved this problem by garbage collect eagerly every hundreds of files:

int index;
while () {
    try {
        // do with outputStream...
    } finally {
        out.close();
    }
    if (index++ % 100 = 0)
        System.gc();
}

scroll image with continuous scrolling using marquee tag

I think you set the marquee width related to 5 images total width. It works fine

ex: <marquee style="width:700px"></marquee>

How to run vi on docker container?

If you need to change a file just once. You should prefer making the change locally and build a new docker image with this file.

Say in a docker image, you need to change a file named myFile.xml under /path/to/docker/image/. So, you need to do.

  1. Copy myFile.xml in your local filesystem and make necessary changes.
  2. Create a file named 'Dockerfile' with the following content-
FROM docker-repo:tag
ADD myFile.xml /path/to/docker/image/

Then build your own docker image with docker build -t docker-repo:v-x.x.x .

Then use your newly build docker image.

How to get the current working directory in Java?

System.getProperty("java.class.path")

How do I run a file on localhost?

You can do it by running with following command.

php -S localhost:8888

Deny direct access to all .php files except index.php

An oblique answer to the question is to write all the code as classes, apart from the index.php files, which are then the only points of entry. PHP files that contain classes will not cause anything to happen, even if they are invoked directly through Apache.

A direct answer is to include the following in .htaccess:

<FilesMatch "\.php$">
    Order Allow,Deny
    Deny from all
</FilesMatch>
<FilesMatch "index[0-9]?\.php$">
    Order Allow,Deny
    Allow from all
</FilesMatch>

This will allow any file like index.php, index2.php etc to be accessed, but will refuse access of any kind to other .php files. It will not affect other file types.

Does C++ support 'finally' blocks? (And what's this 'RAII' I keep hearing about?)

As many people have stated, the solution is to use C++11 features to avoid finally blocks. One of the features is unique_ptr.

Here is Mephane's answer written using RAII patterns.

#include <vector>
#include <memory>
#include <list>
using namespace std;

class Foo
{
 ...
};

void DoStuff(vector<string> input)
{
    list<unique_ptr<Foo> > myList;

    for (int i = 0; i < input.size(); ++i)
    {
      myList.push_back(unique_ptr<Foo>(new Foo(input[i])));
    }

    DoSomeStuff(myList);
}

Some more introduction to using unique_ptr with C++ Standard Library containers is here

How can I validate a string to only allow alphanumeric characters in it?

You could do it easily with an extension function rather than a regex ...

public static bool IsAlphaNum(this string str)
{
    if (string.IsNullOrEmpty(str))
        return false;

    for (int i = 0; i < str.Length; i++)
    {
        if (!(char.IsLetter(str[i])) && (!(char.IsNumber(str[i]))))
            return false;
    }

    return true;
}

Per comment :) ...

public static bool IsAlphaNum(this string str)
{
    if (string.IsNullOrEmpty(str))
        return false;

    return (str.ToCharArray().All(c => Char.IsLetter(c) || Char.IsNumber(c)));
}

creating json object with variables

Try this to see how you can create a object from strings.

var firstName = "xx";
var lastName  = "xy";
var phone     = "xz";
var adress    = "x1";
var obj = {"firstName":firstName, "lastName":lastName, "phone":phone, "address":adress};
console.log(obj);

Create <div> and append <div> dynamically

window.onload = function() {
  var iDiv = document.createElement('div');
  iDiv.id = 'block';
  iDiv.className = 'block';
  document.body.appendChild(iDiv);

  var iiDiv = document.createElement('div');
  iiDiv.className = 'block-2';

  var s = document.getElementById('block');
  s.appendChild(iiDiv);
}

C++ wait for user input

a do while loop would be a nice way to wait for the user input. Like this:

int main() 
{

 do 
 {
   cout << '\n' << "Press a key to continue...";
 } while (cin.get() != '\n');

 return 0;
}

You can also use the function system('PAUSE') but I think this is a bit slower and platform dependent