Programs & Examples On #Rpx

What type of hash does WordPress use?

By default wordpress uses MD5. You can upgrade it to blowfish or extended DES.

http://frameworkgeek.com/support/what-hash-does-wordpress-use/

Changing the action of a form with JavaScript/jQuery

Use Java script to change action url dynamically Works for me well

function chgAction( action_name )
{

 {% for data in sidebar_menu_data %}

     if( action_name== "ABC"){ document.forms.action = "/ABC/";
     }
     else if( action_name== "XYZ"){ document.forms.action = "/XYZ/";
     }

}

<form name="forms" method="post" action="<put default url>" onSubmit="return checkForm(this);">{% csrf_token %} 

How to get an ASP.NET MVC Ajax response to redirect to new page instead of inserting view into UpdateTargetId?

The behavior you're trying to produce is not really best done using AJAX. AJAX would be best used if you wanted to only update a portion of the page, not completely redirect to some other page. That defeats the whole purpose of AJAX really.

I would suggest to just not use AJAX with the behavior you're describing.

Alternatively, you could try using jquery Ajax, which would submit the request and then you specify a callback when the request completes. In the callback you could determine if it failed or succeeded, and redirect to another page on success. I've found jquery Ajax to be much easier to use, especially since I'm already using the library for other things anyway.

You can find documentation about jquery ajax here, but the syntax is as follows:

jQuery.ajax( options )  

jQuery.get( url, data, callback, type)

jQuery.getJSON( url, data, callback )

jQuery.getScript( url, callback )

jQuery.post( url, data, callback, type)

Python truncate a long string

info = data[:min(len(data), 75)

SSL cert "err_cert_authority_invalid" on mobile chrome only

I had this same problem while hosting a web site via Parse and using a Comodo SSL cert resold by NameCheap.

You will receive two cert files inside of a zip folder: www_yourdomain_com.ca-bundle www_yourdomain_com.crt

You can only upload one file to Parse: Parse SSL Cert Input Box

In terminal combine the two files using:

cat www_yourdomain_com.crt www_yourdomain_com.ca-bundle > www_yourdomain_com_combine.crt

Then upload to Parse. This should fix the issue with Android Chrome and Firefox browsers. You can verify that it worked by testing it at https://www.sslchecker.com/sslchecker

How do I calculate a trendline for a graph?

Regarding a previous answer

if (B) y = offset + slope*x

then (C) offset = y/(slope*x) is wrong

(C) should be:

offset = y-(slope*x)

See: http://zedgraph.org/wiki/index.php?title=Trend

Centering a button vertically in table cell, using Twitter Bootstrap

add this to your css

.table-vcenter td {
   vertical-align: middle!important;
}

then add to the class to your table:

        <table class="table table-hover table-striped table-vcenter">

Easy way of running the same junit test over and over?

With IntelliJ, you can do this from the test configuration. Once you open this window, you can choose to run the test any number of times you want,.

enter image description here

when you run the test, intellij will execute all tests you have selected for the number of times you specified.

Example running 624 tests 10 times: enter image description here

Adding rows to tbody of a table using jQuery

("#tblEntAttributes tbody")

needs to be

$("#tblEntAttributes tbody").

You are not selecting the element with the correct syntax

Here's an example of both

$(newRowContent).appendTo($("#tblEntAttributes"));

and

$("#tblEntAttributes tbody").append(newRowContent);

working http://jsfiddle.net/xW4NZ/

How to make a JFrame button open another JFrame class in Netbeans?

JFrame.setVisible(true);

You can either use setVisible(false) or dispose() method to disappear current form.

Get Date Object In UTC format in Java

In java 8 , It's really easy to get timestamp in UTC by using java 8 java.time.Instant library :

Instant.now();

That few word of code will return the UTC Timestamp.

cast_sender.js error: Failed to load resource: net::ERR_FAILED in Chrome

In addition to what was already said - in order to avoid this error from interfering (stopping) other Javascript code on your page, you could try forcing the YouTube iframe to load last - after all other Javascript code is loaded.

Copy all files with a certain extension from all subdirectories

I had a similar problem. I solved it using:

find dir_name '*.mp3' -exec cp -vuni '{}' "../dest_dir" ";"

The '{}' and ";" executes the copy on each file.

How to send post request to the below post method using postman rest client

The Interface of Postman is changing acccording to the updates.

So You can get full information about postman can get Here.

https://www.getpostman.com/docs/requests

Jenkins fails when running "service start jenkins"

I faced same issue while setting up jenkins, the problem is that java is not installed and hence not available in path.

The simplest way is to use scp here to copy jdk binaries to aws ec2 box, script won't work if you make one as they keep on updating download urls(Orale, i mean): scp -i C:/Users/key-pair.pem jdk-8u191-linux-x64.tar.gz ec2- [email protected]:~/

$cd /opt

$sudo cp /home/ec2-user/jdk* .

$sudo chmod +x jdk*

$sudo tar xzf jdk-8u191-linux-x64.tar.gz

$sudo tar xzf jdk-8u191-linux-x64.tar.gz

$cd jdk1.8.0_191/

$sudo alternatives --install /usr/bin/java java /opt/jdk1.8.0_191/bin/java 2

$sudo alternatives --config java

Here I download tar.gz file in loal windows and transferred over scp to AWS ec2-user, default dir. Hope it helps.

Storing images in SQL Server?

Why it can be good to store pictures in the database an not in a catalog on the web server.

You have made an application with lots of pictures stored in a folder on the server, that the client has used for years.

Now they come to you. They server has been destroyed and they need to restore it on a new server. They have no access to the old server anymore. The only backup they have is the database backup.

You have of course the source and can simple deploy it to the new server, install SqlServer and restore the database. But now all the pictures are gone.

If you have saved the pictures in SqlServer everything will work as before.

Just my 2 cents.

Downloading a file from spring controllers

something like below

@RequestMapping(value = "/download", method = RequestMethod.GET)
public void getFile(HttpServletResponse response) {
    try {
        DefaultResourceLoader loader = new DefaultResourceLoader();
        InputStream is = loader.getResource("classpath:META-INF/resources/Accepted.pdf").getInputStream();
        IOUtils.copy(is, response.getOutputStream());
        response.setHeader("Content-Disposition", "attachment; filename=Accepted.pdf");
        response.flushBuffer();
    } catch (IOException ex) {
        throw new RuntimeException("IOError writing file to output stream");
    }
}

You can display PDF or download it examples here

How to check if one of the following items is in a list?

>>> L1 = [2,3,4]
>>> L2 = [1,2]
>>> [i for i in L1 if i in L2]
[2]


>>> S1 = set(L1)
>>> S2 = set(L2)
>>> S1.intersection(S2)
set([2])

Both empty lists and empty sets are False, so you can use the value directly as a truth value.

Kotlin - Property initialization using "by lazy" vs. "lateinit"

lateinit vs lazy

  1. lateinit

    i) Use it with mutable variable[var]

     lateinit var name: String       //Allowed
     lateinit val name: String       //Not Allowed
    

ii) Allowed with only non-nullable data types

    lateinit var name: String       //Allowed
    lateinit var name: String?      //Not Allowed

iii) It is a promise to compiler that the value will be initialized in future.

NOTE: If you try to access lateinit variable without initializing it then it throws UnInitializedPropertyAccessException.

  1. lazy

    i) Lazy initialization was designed to prevent unnecessary initialization of objects.

ii) Your variable will not be initialized unless you use it.

iii) It is initialized only once. Next time when you use it, you get the value from cache memory.

iv) It is thread safe(It is initialized in the thread where it is used for the first time. Other threads use the same value stored in the cache).

v) The variable can only be val.

vi) The variable can only be non-nullable.

Multiline editing in Visual Studio Code

Use Ctrl + D to use multi word edit of same words in Windows and Linux.

Use CMD + D for Mac.

Drop columns whose name contains a specific string from pandas DataFrame

import pandas as pd

import numpy as np

array=np.random.random((2,4))

df=pd.DataFrame(array, columns=('Test1', 'toto', 'test2', 'riri'))

print df

      Test1      toto     test2      riri
0  0.923249  0.572528  0.845464  0.144891
1  0.020438  0.332540  0.144455  0.741412

cols = [c for c in df.columns if c.lower()[:4] != 'test']

df=df[cols]

print df
       toto      riri
0  0.572528  0.144891
1  0.332540  0.741412

What is the difference between a 'closure' and a 'lambda'?

It depends on whether a function uses external variable or not to perform operation.

External variables - variables defined outside the scope of a function.

  • Lambda expressions are stateless because It depends on parameters, internal variables or constants to perform operations.

    Function<Integer,Integer> lambda = t -> {
        int n = 2
        return t * n 
    }
    
  • Closures hold state because it uses external variables (i.e. variable defined outside the scope of the function body) along with parameters and constants to perform operations.

    int n = 2
    
    Function<Integer,Integer> closure = t -> {
        return t * n 
    }
    

When Java creates closure, it keeps the variable n with the function so it can be referenced when passed to other functions or used anywhere.

Returning anonymous type in C#

You can't.

You can only return object, or container of objects, e.g. IEnumerable<object>, IList<object>, etc.

RuntimeWarning: DateTimeField received a naive datetime

Use django.utils.timezone.make_aware function to make your naive datetime objects timezone aware and avoid those warnings.

It converts naive datetime object (without timezone info) to the one that has timezone info (using timezone specified in your django settings if you don't specify it explicitly as a second argument):

import datetime
from django.conf import settings
from django.utils.timezone import make_aware

naive_datetime = datetime.datetime.now()
naive_datetime.tzinfo  # None

settings.TIME_ZONE  # 'UTC'
aware_datetime = make_aware(naive_datetime)
aware_datetime.tzinfo  # <UTC>

Access parent DataContext from DataTemplate

RelativeSource vs. ElementName

These two approaches can achieve the same result,

RelativeSource

Binding="{Binding Path=DataContext.MyBindingProperty, 
          RelativeSource={RelativeSource AncestorType={x:Type Window}}}"

This method looks for a control of a type Window (in this example) in the visual tree and when it finds it you basically can access it's DataContext using the Path=DataContext..... The Pros about this method is that you don't need to be tied to a name and it's kind of dynamic, however, changes made to your visual tree can affect this method and possibly break it.

ElementName

Binding="{Binding Path=DataContext.MyBindingProperty, ElementName=MyMainWindow}

This method referes to a solid static Name so as long as your scope can see it, you're fine.You should be sticking to your naming convention not to break this method of course.The approach is qute simple and all you need is to specify a Name="..." for your Window/UserControl.

Although all three types (RelativeSource, Source, ElementName) are capable of doing the same thing, but according to the following MSDN article, each one better be used in their own area of specialty.

How to: Specify the Binding Source

Find the brief description of each plus a link to a more details one in the table on the bottom of the page.

What's the difference between disabled="disabled" and readonly="readonly" for HTML form input fields?

Disabled means that no data from that form element will be submitted when the form is submitted. Read-only means any data from within the element will be submitted, but it cannot be changed by the user.

For example:

<input type="text" name="yourname" value="Bob" readonly="readonly" />

This will submit the value "Bob" for the element "yourname".

<input type="text" name="yourname" value="Bob" disabled="disabled" />

This will submit nothing for the element "yourname".

.Contains() on a list of custom class objects

If you want to have control over this you need to implement the [IEquatable interface][1]

[1]: http://This method determines equality by using the default equality comparer, as defined by the object's implementation of the IEquatable.Equals method for T (the type of values in the list).

How to change the style of the title attribute inside an anchor tag?

Native tooltip cannot be styled.

That being said, you can use some library that would show styles floating layers when element is being hovered (instead of the native tooltips, and suppress them) requiring little or no code modifications...

Google Map API - Removing Markers

Following code might be useful if someone is using React and has a different component of Marker and want to remove marker from map.

export default function useGoogleMapMarker(props) {
  const [marker, setMarker] = useState();

  useEffect(() => {
    // ...code
    const marker = new maps.Marker({ position, map, title, icon });
    // ...code
    setMarker(marker);
    return () => marker.setMap(null); // to remove markers when unmounts
  }, []);

  return marker;
}

change the date format in laravel view page

You can use Carbon::createFromTimestamp

BLADE

{{ \Carbon\Carbon::createFromTimestamp(strtotime($user->from_date))->format('d-m-Y')}}

How to "perfectly" override a dict?

My requirements were a bit stricter:

  • I had to retain case info (the strings are paths to files displayed to the user, but it's a windows app so internally all operations must be case insensitive)
  • I needed keys to be as small as possible (it did make a difference in memory performance, chopped off 110 mb out of 370). This meant that caching lowercase version of keys is not an option.
  • I needed creation of the data structures to be as fast as possible (again made a difference in performance, speed this time). I had to go with a builtin

My initial thought was to substitute our clunky Path class for a case insensitive unicode subclass - but:

  • proved hard to get that right - see: A case insensitive string class in python
  • turns out that explicit dict keys handling makes code verbose and messy - and error prone (structures are passed hither and thither, and it is not clear if they have CIStr instances as keys/elements, easy to forget plus some_dict[CIstr(path)] is ugly)

So I had finally to write down that case insensitive dict. Thanks to code by @AaronHall that was made 10 times easier.

class CIstr(unicode):
    """See https://stackoverflow.com/a/43122305/281545, especially for inlines"""
    __slots__ = () # does make a difference in memory performance

    #--Hash/Compare
    def __hash__(self):
        return hash(self.lower())
    def __eq__(self, other):
        if isinstance(other, CIstr):
            return self.lower() == other.lower()
        return NotImplemented
    def __ne__(self, other):
        if isinstance(other, CIstr):
            return self.lower() != other.lower()
        return NotImplemented
    def __lt__(self, other):
        if isinstance(other, CIstr):
            return self.lower() < other.lower()
        return NotImplemented
    def __ge__(self, other):
        if isinstance(other, CIstr):
            return self.lower() >= other.lower()
        return NotImplemented
    def __gt__(self, other):
        if isinstance(other, CIstr):
            return self.lower() > other.lower()
        return NotImplemented
    def __le__(self, other):
        if isinstance(other, CIstr):
            return self.lower() <= other.lower()
        return NotImplemented
    #--repr
    def __repr__(self):
        return '{0}({1})'.format(type(self).__name__,
                                 super(CIstr, self).__repr__())

def _ci_str(maybe_str):
    """dict keys can be any hashable object - only call CIstr if str"""
    return CIstr(maybe_str) if isinstance(maybe_str, basestring) else maybe_str

class LowerDict(dict):
    """Dictionary that transforms its keys to CIstr instances.
    Adapted from: https://stackoverflow.com/a/39375731/281545
    """
    __slots__ = () # no __dict__ - that would be redundant

    @staticmethod # because this doesn't make sense as a global function.
    def _process_args(mapping=(), **kwargs):
        if hasattr(mapping, 'iteritems'):
            mapping = getattr(mapping, 'iteritems')()
        return ((_ci_str(k), v) for k, v in
                chain(mapping, getattr(kwargs, 'iteritems')()))
    def __init__(self, mapping=(), **kwargs):
        # dicts take a mapping or iterable as their optional first argument
        super(LowerDict, self).__init__(self._process_args(mapping, **kwargs))
    def __getitem__(self, k):
        return super(LowerDict, self).__getitem__(_ci_str(k))
    def __setitem__(self, k, v):
        return super(LowerDict, self).__setitem__(_ci_str(k), v)
    def __delitem__(self, k):
        return super(LowerDict, self).__delitem__(_ci_str(k))
    def copy(self): # don't delegate w/ super - dict.copy() -> dict :(
        return type(self)(self)
    def get(self, k, default=None):
        return super(LowerDict, self).get(_ci_str(k), default)
    def setdefault(self, k, default=None):
        return super(LowerDict, self).setdefault(_ci_str(k), default)
    __no_default = object()
    def pop(self, k, v=__no_default):
        if v is LowerDict.__no_default:
            # super will raise KeyError if no default and key does not exist
            return super(LowerDict, self).pop(_ci_str(k))
        return super(LowerDict, self).pop(_ci_str(k), v)
    def update(self, mapping=(), **kwargs):
        super(LowerDict, self).update(self._process_args(mapping, **kwargs))
    def __contains__(self, k):
        return super(LowerDict, self).__contains__(_ci_str(k))
    @classmethod
    def fromkeys(cls, keys, v=None):
        return super(LowerDict, cls).fromkeys((_ci_str(k) for k in keys), v)
    def __repr__(self):
        return '{0}({1})'.format(type(self).__name__,
                                 super(LowerDict, self).__repr__())

Implicit vs explicit is still a problem, but once dust settles, renaming of attributes/variables to start with ci (and a big fat doc comment explaining that ci stands for case insensitive) I think is a perfect solution - as readers of the code must be fully aware that we are dealing with case insensitive underlying data structures. This will hopefully fix some hard to reproduce bugs, which I suspect boil down to case sensitivity.

Comments/corrections welcome :)

How do I make a <div> move up and down when I'm scrolling the page?

using position:fixed alone is just fine when you don't have a header or logo at the top of your page. This solution will take into account the how far the window has scrolled, and moves the div when you scrolled past your header. It will then lock it back into place when you get to the top again.

if($(window).scrollTop() > Height_of_Header){
    //begin to scroll
    $("#div").css("position","fixed");
    $("#div").css("top",0);
}
else{
    //lock it back into place
    $("#div").css("position","relative");
}

What is the default encoding of the JVM?

There are three "default" encodings:

  • file.encoding:
    System.getProperty("file.encoding")

  • java.nio.Charset:
    Charset.defaultCharset()

  • And the encoding of the InputStreamReader:
    InputStreamReader.getEncoding()

You can read more about it on this page.

How can I have two fixed width columns with one flexible column in the center?

Instead of using width (which is a suggestion when using flexbox), you could use flex: 0 0 230px; which means:

  • 0 = don't grow (shorthand for flex-grow)
  • 0 = don't shrink (shorthand for flex-shrink)
  • 230px = start at 230px (shorthand for flex-basis)

which means: always be 230px.

See fiddle, thanks @TylerH

Oh, and you don't need the justify-content and align-items here.

img {
    max-width: 100%;
}
#container {
    display: flex;
    x-justify-content: space-around;
    x-align-items: stretch;
    max-width: 1200px;
}
.column.left {
    width: 230px;
    flex: 0 0 230px;
}
.column.right {
    width: 230px;
    flex: 0 0 230px;
    border-left: 1px solid #eee;
}
.column.center {
    border-left: 1px solid #eee;
}

How do I animate constraint changes?

Generally, you just need to update constraints and call layoutIfNeeded inside the animation block. This can be either changing the .constant property of an NSLayoutConstraint, adding remove constraints (iOS 7), or changing the .active property of constraints (iOS 8 & 9).

Sample Code:

[UIView animateWithDuration:0.3 animations:^{
    // Move to right
    self.leadingConstraint.active = false;
    self.trailingConstraint.active = true;

    // Move to bottom
    self.topConstraint.active = false;
    self.bottomConstraint.active = true;

    // Make the animation happen
    [self.view setNeedsLayout];
    [self.view layoutIfNeeded];
}];

Sample Setup:

Xcode Project so sample animation project.

Controversy

There are some questions about whether the constraint should be changed before the animation block, or inside it (see previous answers).

The following is a Twitter conversation between Martin Pilkington who teaches iOS, and Ken Ferry who wrote Auto Layout. Ken explains that though changing constants outside of the animation block may currently work, it's not safe and they should really be change inside the animation block. https://twitter.com/kongtomorrow/status/440627401018466305

Animation:

Sample Project

Here's a simple project showing how a view can be animated. It's using Objective C and animates the view by changing the .active property of several constraints. https://github.com/shepting/SampleAutoLayoutAnimation

Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2)

I have the same problem and when I digged into the log:

sudo tail -f /var/log/mysqld.log

InnoDB: mmap(137363456 bytes) failed; errno 12
200610  6:27:27 InnoDB: Completed initialization of buffer pool
200610  6:27:27 InnoDB: Fatal error: cannot allocate memory for the buffer pool
200610  6:27:27 [ERROR] Plugin 'InnoDB' init function returned error.
200610  6:27:27 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
200610  6:27:27 [ERROR] Unknown/unsupported storage engine: InnoDB
200610  6:27:27 [ERROR] Aborting

Clearly there's not enough memory and stopping InnoDB to start. I realized I never set up the swap file...

I followed this to set up the swap file and it works.

Do you get charged for a 'stopped' instance on EC2?

No.

You get charged for:

  1. Online time
  2. Storage space (assumably you store the image on S3 [EBS])
  3. Elastic IP addresses
  4. Bandwidth

So... if you stop the EC2 instance you will only have to pay for the storage of the image on S3 (assuming you store an image ofcourse) and any IP addresses you've reserved.

What is move semantics?

Suppose you have a function that returns a substantial object:

Matrix multiply(const Matrix &a, const Matrix &b);

When you write code like this:

Matrix r = multiply(a, b);

then an ordinary C++ compiler will create a temporary object for the result of multiply(), call the copy constructor to initialise r, and then destruct the temporary return value. Move semantics in C++0x allow the "move constructor" to be called to initialise r by copying its contents, and then discard the temporary value without having to destruct it.

This is especially important if (like perhaps the Matrix example above), the object being copied allocates extra memory on the heap to store its internal representation. A copy constructor would have to either make a full copy of the internal representation, or use reference counting and copy-on-write semantics interally. A move constructor would leave the heap memory alone and just copy the pointer inside the Matrix object.

Bootstrap modal not displaying

I tracked down the reason.

Just to give it some general usefulness to anyone coming to this question. If you can't figure out what's wrong, try doing a 'search all' for any classes of 'modal' 'fade' 'fade in' and 'hide' in any style sheets in your application.

I had a single instance of 'fade' being defined in a random css file, and that's what was stopping it displaying as it was overriding bootstrap. Once I deleted the reference, everything was ok.

Angularjs $q.all

The issue seems to be that you are adding the deffered.promise when deffered is itself the promise you should be adding:

Try changing to promises.push(deffered); so you don't add the unwrapped promise to the array.

 UploadService.uploadQuestion = function(questions){

            var promises = [];

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

                var deffered  = $q.defer();
                var question  = questions[i]; 

                $http({

                    url   : 'upload/question',
                    method: 'POST',
                    data  : question
                }).
                success(function(data){
                    deffered.resolve(data);
                }).
                error(function(error){
                    deffered.reject();
                });

                promises.push(deffered);
            }

            return $q.all(promises);
        }

How to get rid of blank pages in PDF exported from SSRS

If the pages are blank coming from SSRS, you need to tweak your report layout. This will be far more efficient than running the output through and post process to repair the side effects of a layout problem.

SSRS is very finicky when it comes to pushing the boundaries of the margins. It is easy to accidentally widen/lengthen the report just by adjusting text box or other control on the report. Check the width and height property of the report surface carefully and squeeze them as much as possible. Watch out for large headers and footers.

What is {this.props.children} and when you should use it?

I assume you're seeing this in a React component's render method, like this (edit: your edited question does indeed show that):

_x000D_
_x000D_
class Example extends React.Component {_x000D_
  render() {_x000D_
    return <div>_x000D_
      <div>Children ({this.props.children.length}):</div>_x000D_
      {this.props.children}_x000D_
    </div>;_x000D_
  }_x000D_
}_x000D_
_x000D_
class Widget extends React.Component {_x000D_
  render() {_x000D_
    return <div>_x000D_
      <div>First <code>Example</code>:</div>_x000D_
      <Example>_x000D_
        <div>1</div>_x000D_
        <div>2</div>_x000D_
        <div>3</div>_x000D_
      </Example>_x000D_
      <div>Second <code>Example</code> with different children:</div>_x000D_
      <Example>_x000D_
        <div>A</div>_x000D_
        <div>B</div>_x000D_
      </Example>_x000D_
    </div>;_x000D_
  }_x000D_
}_x000D_
_x000D_
ReactDOM.render(_x000D_
  <Widget/>,_x000D_
  document.getElementById("root")_x000D_
);
_x000D_
<div id="root"></div>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react.min.js"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.1.0/react-dom.min.js"></script>
_x000D_
_x000D_
_x000D_

children is a special property of React components which contains any child elements defined within the component, e.g. the divs inside Example above. {this.props.children} includes those children in the rendered result.

...what are the situations to use the same

You'd do it when you want to include the child elements in the rendered output directly, unchanged; and not if you didn't.

C++, how to declare a struct in a header file

C++, how to declare a struct in a header file:

Put this in a file called main.cpp:

#include <cstdlib>
#include <iostream>
#include "student.h"

using namespace std;    //Watchout for clashes between std and other libraries

int main(int argc, char** argv) {
    struct Student s1;
    s1.firstName = "fred"; s1.lastName = "flintstone";
    cout << s1.firstName << " " << s1.lastName << endl;
    return 0;
}

put this in a file named student.h

#ifndef STUDENT_H
#define STUDENT_H

#include<string>
struct Student {
    std::string lastName, firstName;
};

#endif

Compile it and run it, it should produce this output:

s1.firstName = "fred";

Protip:

You should not place a using namespace std; directive in the C++ header file because you may cause silent name clashes between different libraries. To remedy this, use the fully qualified name: std::string foobarstring; instead of including the std namespace with string foobarstring;.

Histogram using gnuplot?

I have a couple corrections/additions to Born2Smile's very useful answer:

  1. Empty bins caused the box for the adjacent bin to incorrectly extend into its space; avoid this using set boxwidth binwidth
  2. In Born2Smile's version, bins are rendered as centered on their lower bound. Strictly they ought to extend from the lower bound to the upper bound. This can be corrected by modifying the bin function: bin(x,width)=width*floor(x/width) + width/2.0

1114 (HY000): The table is full

This could also be the InnoDB limit for the number of open transactions:

http://bugs.mysql.com/bug.php?id=26590

at 1024 transactions, that have undo records (as in, edited any data), InnoDB will fail to work

How can I set an SQL Server connection string?

sa is a system administrator account which comes with SQL Server by default. As you know might already know, you can use two ways to log in to SQL Server.

screen shot of SQL Server Management Studio

Therefore there are connection strings which suitable for each scenario (such as Windows authentication, localdb, etc.). Use SQL Server Connection Strings for ASP.NET Web Applications to build your connection string. These are XML tags. You just need a value of connectionString.

How is CountDownLatch used in Java Multithreading?

One good example of when to use something like this is with Java Simple Serial Connector, accessing serial ports. Typically you'll write something to the port, and asyncronously, on another thread, the device will respond on a SerialPortEventListener. Typically, you'll want to pause after writing to the port to wait for the response. Handling the thread locks for this scenario manually is extremely tricky, but using Countdownlatch is easy. Before you go thinking you can do it another way, be careful about race conditions you never thought of!!

Pseudocode:

CountDownLatch latch;
void writeData() { 
   latch = new CountDownLatch(1);
   serialPort.writeBytes(sb.toString().getBytes())
   try {
      latch.await(4, TimeUnit.SECONDS);
    } catch (InterruptedException e) {
   }
}
class SerialPortReader implements SerialPortEventListener {
    public void serialEvent(SerialPortEvent event) {
        if(event.isRXCHAR()){//If data is available
            byte buffer[] = serialPort.readBytes(event.getEventValue());
            latch.countDown();
         }
     }
}

SQLite UPSERT / UPDATE OR INSERT

You can also just add an ON CONFLICT REPLACE clause to your user_name unique constraint and then just INSERT away, leaving it to SQLite to figure out what to do in case of a conflict. See:https://sqlite.org/lang_conflict.html.

Also note the sentence regarding delete triggers: When the REPLACE conflict resolution strategy deletes rows in order to satisfy a constraint, delete triggers fire if and only if recursive triggers are enabled.

Make error: missing separator

Just for grins, and in case somebody else runs into a similar error:

I got the infamous "missing separator" error because I had invoked a rule defining a function as

($eval $(call function,args))

rather than

$(eval $(call function,args))

i.e. ($ rather than $(.

How to open the second form?

On any click event (or other one):

Form2 frm2 = new Form2();
frm2.Show();

Add/delete row from a table

Here's the code JS Bin using jQuery. Tested on all the browsers. Here, we have to click the rows in order to delete it with beautiful effect. Hope it helps.

Spring Test & Security: How to mock authentication?

Here is an example for those who want to Test Spring MockMvc Security Config using Base64 basic authentication.

String basicDigestHeaderValue = "Basic " + new String(Base64.encodeBase64(("<username>:<password>").getBytes()));
this.mockMvc.perform(get("</get/url>").header("Authorization", basicDigestHeaderValue).accept(MediaType.APPLICATION_JSON)).andExpect(status().isOk());

Maven Dependency

    <dependency>
        <groupId>commons-codec</groupId>
        <artifactId>commons-codec</artifactId>
        <version>1.3</version>
    </dependency>

What is the use of the @Temporal annotation in Hibernate?

If you're looking for short answer:

In the case of using java.util.Date, Java doesn't really know how to directly relate to SQL types. This is when @Temporal comes into play. It's used to specify the desired SQL type.

Source: Baeldung

Setting Windows PATH for Postgres tools

Incase any one still wondering how to add environment variables then please use this link to add variables. Link: https://sqlbackupandftp.com/blog/setting-windows-path-for-postgres-tools

Single-threaded apartment - cannot instantiate ActiveX control

If you used [STAThread] to the main entry of your application and still get the error you may need to make a Thread-Safe call to the control... something like below. In my case with the same problem the following solution worked!

Private void YourFunc(..)
{
    if (this.InvokeRequired)
    {
        Invoke(new MethodInvoker(delegate()
        {
           // Call your method YourFunc(..);
        }));
    }
    else
    {
        ///
    }

count number of rows in a data frame in R based on group

Here is another way of using aggregate to count rows by group:

my.data <- read.table(text = '
    month.year    my.cov
      Jan.2000     apple
      Jan.2000      pear
      Jan.2000     peach
      Jan.2001     apple
      Jan.2001     peach
      Feb.2002      pear
', header = TRUE, stringsAsFactors = FALSE, na.strings = NA)

rows.per.group  <- aggregate(rep(1, length(my.data$month.year)),
                             by=list(my.data$month.year), sum)
rows.per.group

#    Group.1 x
# 1 Feb.2002 1
# 2 Jan.2000 3
# 3 Jan.2001 2

Only Add Unique Item To List

//HashSet allows only the unique values to the list
HashSet<int> uniqueList = new HashSet<int>();

var a = uniqueList.Add(1);
var b = uniqueList.Add(2);
var c = uniqueList.Add(3);
var d = uniqueList.Add(2); // should not be added to the list but will not crash the app

//Dictionary allows only the unique Keys to the list, Values can be repeated
Dictionary<int, string> dict = new Dictionary<int, string>();

dict.Add(1,"Happy");
dict.Add(2, "Smile");
dict.Add(3, "Happy");
dict.Add(2, "Sad"); // should be failed // Run time error "An item with the same key has already been added." App will crash

//Dictionary allows only the unique Keys to the list, Values can be repeated
Dictionary<string, int> dictRev = new Dictionary<string, int>();

dictRev.Add("Happy", 1);
dictRev.Add("Smile", 2);
dictRev.Add("Happy", 3); // should be failed // Run time error "An item with the same key has already been added." App will crash
dictRev.Add("Sad", 2);

Bootstrap Dropdown with Hover

html

        <div class="dropdown">

            <button class="btn btn-primary dropdown-toggle" type="button" data-toggle="dropdown">
                Dropdown Example <span class="caret"></span>
            </button>

            <ul class="dropdown-menu">
                <li><a href="#">HTML</a></li>
                <li><a href="#">CSS</a></li>
                <li><a href="#">JavaScript</a></li>
            </ul>

        </div> 

jquery

        $(document).ready( function() {                

            /* $(selector).hover( inFunction, outFunction ) */
            $('.dropdown').hover( 
                function() {                        
                    $(this).find('ul').css({
                        "display": "block",
                        "margin-top": 0
                    });                        
                }, 
                function() {                        
                    $(this).find('ul').css({
                        "display": "none",
                        "margin-top": 0
                    });                        
                } 
            );

        });

codepen

What is the most effective way to get the index of an iterator of an std::vector?

As UncleBens and Naveen have shown, there are good reasons for both. Which one is "better" depends on what behavior you want: Do you want to guarantee constant-time behavior, or do you want it to fall back to linear time when necessary?

it - vec.begin() takes constant time, but the operator - is only defined on random access iterators, so the code won't compile at all with list iterators, for example.

std::distance(vec.begin(), it) works for all iterator types, but will only be a constant-time operation if used on random access iterators.

Neither one is "better". Use the one that does what you need.

How can getContentResolver() be called in Android?

The getContentResolver()method is also used when you query a Contact, using a Cursor object. I have used getContentResolver() to query the Android phone Contacts app, looking for contact info from a person's phone number, to include in my app. The different elements in a query (as shown below) represent what kind of contact details you want, and if they should be ordered, etc. Here is another example.

From the Content Provider Basics page from Android docs.

// Queries the user dictionary and returns results
mCursor = getContentResolver().query(
    UserDictionary.Words.CONTENT_URI,   // The content URI of the words table
    mProjection,                        // The columns to return for each row
    mSelectionClause                    // Selection criteria
    mSelectionArgs,                     // Selection criteria
    mSortOrder);                        // The sort order for the returned rows

Default port for SQL Server

If you have access to the server then you can use

select local_tcp_port from sys.dm_exec_connections where local_tcp_port is not null

For full details see port number of SQL Server

Referencing a string in a string array resource with xml

Unfortunately:

  • It seems you can not reference a single item from an array in values/arrays.xml with XML. Of course you can in Java, but not XML. There's no information on doing so in the Android developer reference, and I could not find any anywhere else.

  • It seems you can't use an array as a key in the preferences layout. Each key has to be a single value with it's own key name.

What I want to accomplish: I want to be able to loop through the 17 preferences, check if the item is checked, and if it is, load the string from the string array for that preference name.

Here's the code I was hoping would complete this task:

SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getBaseContext());  
ArrayAdapter<String> itemsArrayList = new ArrayAdapter<String>(getBaseContext(),   android.R.layout.simple_list_item_1);  
String[] itemNames = getResources().getStringArray(R.array.itemNames_array);  


for (int i = 0; i < 16; i++) {  
    if (prefs.getBoolean("itemKey[i]", true)) {  
        itemsArrayList.add(itemNames[i]);  
    }  
} 

What I did:

  • I set a single string for each of the items, and referenced the single strings in the . I use the single string reference for the preferences layout checkbox titles, and the array for my loop.

  • To loop through the preferences, I just named the keys like key1, key2, key3, etc. Since you reference a key with a string, you have the option to "build" the key name at runtime.

Here's the new code:

for (int i = 0; i < 16; i++) {  
        if (prefs.getBoolean("itemKey" + String.valueOf(i), true)) {  
        itemsArrayList.add(itemNames[i]);  
    }  
}

When to use references vs. pointers

Points to keep in mind:

  1. Pointers can be NULL, references cannot be NULL.

  2. References are easier to use, const can be used for a reference when we don't want to change value and just need a reference in a function.

  3. Pointer used with a * while references used with a &.

  4. Use pointers when pointer arithmetic operation are required.

  5. You can have pointers to a void type int a=5; void *p = &a; but cannot have a reference to a void type.

Pointer Vs Reference

void fun(int *a)
{
    cout<<a<<'\n'; // address of a = 0x7fff79f83eac
    cout<<*a<<'\n'; // value at a = 5
    cout<<a+1<<'\n'; // address of a increment by 4 bytes(int) = 0x7fff79f83eb0
    cout<<*(a+1)<<'\n'; // value here is by default = 0
}
void fun(int &a)
{
    cout<<a<<'\n'; // reference of original a passed a = 5
}
int a=5;
fun(&a);
fun(a);

Verdict when to use what

Pointer: For array, linklist, tree implementations and pointer arithmetic.

Reference: In function parameters and return types.

PackagesNotFoundError: The following packages are not available from current channels:

Have you tried:

pip install <package>

or

conda install -c conda-forge <package>

jQuery checkbox check/uncheck

 $('mainCheckBox').click(function(){
    if($(this).prop('checked')){
        $('Id or Class of checkbox').prop('checked', true);
    }else{
        $('Id or Class of checkbox').prop('checked', false);
    }
});

How to solve "Kernel panic - not syncing - Attempted to kill init" -- without erasing any user data

if the full message is:

kernel panic - not syncing: Attempted to kill inint !
PId: 1, comm: init not tainted 2.6.32.-279-5.2.e16.x86_64 #1

then you should have disabled selinux and after that you have rebooted the system.

The easier way is to use a live OS and re-enable it

vim /etc/selinux/config
    ...
    SELINUX=enforcing
    ...

Second choice is to disable selinux in the kernel arguments by adding selinux=0

vim /boot/grub/grub.conf
    ...
    kernel /boot/vmlinuz-2.4.20-selinux-2003040709 ro root=/dev/hda1 nousb selinux=0
    ...

source kernel panic - not syncing: Attempted to kill inint !

Is it possible to execute multiple _addItem calls asynchronously using Google Analytics?

From the docs:

_trackTrans() Sends both the transaction and item data to the Google Analytics server. This method should be called after _trackPageview(), and used in conjunction with the _addItem() and addTrans() methods. It should be called after items and transaction elements have been set up.

So, according to the docs, the items get sent when you call trackTrans(). Until you do, you can add items, but the transaction will not be sent.

Edit: Further reading led me here:

http://www.analyticsmarket.com/blog/edit-ecommerce-data

Where it clearly says you can start another transaction with an existing ID. When you commit it, the new items you listed will be added to that transaction.

Which version of C# am I using

The language version is chosen based on the project's target framework by default.

Each project may use a different version of .Net framework, the best suitable C# compiler will be chosen by default by looking at the target framework. From visual studio, UI will not allow the users to changes the language version, however, we can change the language version by editing the project file with addition of new property group. But this may cause compile/run time issues in existing code.

<PropertyGroup>  
<LangVersion>8.0</LangVersion>  
</PropertyGroup>

I could see the following from Microsoft docs.

The compiler determines a default based on these rules:

Target framework  version     C# language version default
.NET Core           3.x         C# 8.0
.NET Core           2.x         C# 7.3
.NET Standard       2.1         C# 8.0
.NET Standard       2.0         C# 7.3
.NET Standard       1.x         C# 7.3
.NET Framework      all         C# 7.3

When to use CouchDB over MongoDB and vice versa

I'm sure you can with Mongo (more familiar with it), and pretty sure you can with couch too.

Both are documented oriented (JSON-based) so there would be no "columns" but rather fields in documents -- but they can be fully dynamic.

They both do it you may want to look at other factors on which to use: other features you care about, popularity, etc. Google insights, indeed.com job posts would be ways to look at popularity.

You could just try it i think you should be able to have mongo running in 5 minutes.

jQuery: Performing synchronous AJAX requests

You're using the ajax function incorrectly. Since it's synchronous it'll return the data inline like so:

var remote = $.ajax({
    type: "GET",
    url: remote_url,
    async: false
}).responseText;

How to get a list of all valid IP addresses in a local network?

Install nmap,

sudo apt-get install nmap

then

nmap -sP 192.168.1.*

or more commonly

nmap -sn 192.168.1.0/24

will scan the entire .1 to .254 range

This does a simple ping scan in the entire subnet to see which hosts are online.

How to draw a custom UIView that is just a circle - iPhone app

There's another alternative for lazy people. You can set the layer.cornerRadius key path for your view in the Interface Builder. For example, if your view has a width = height of 48, set layer.cornerRadius = 24:

enter image description here

However, this only works if you have a static size of the view (width/height is fixed) and it's not showing the circle in the interface builder.

How to get screen width and height

Within an activity, you can call:

int width = this.getResources().getDisplayMetrics().widthPixels;
int height = this.getResources().getDisplayMetrics().heightPixels;

When you're in a View, then you need to get the Context first:

int width = getContext().getResources().getDisplayMetrics().widthPixels;
int height = getContext().getResources().getDisplayMetrics().heightPixels;

This will work in all Android version, available since API 1, and never deprecated.

JavaScript code to stop form submission

Lets say you have a form similar to this

<form action="membersDeleteAllData.html" method="post">
    <button type="submit" id="btnLoad" onclick="confirmAction(event);">ERASE ALL DATA</button>
</form>

Here is the javascript for the confirmAction function

<script type="text/javascript">
    function confirmAction(e)
    {
        var confirmation = confirm("Are you sure about this ?") ;

        if (!confirmation)
        {
            e.preventDefault() ;
            returnToPreviousPage();
        }

        return confirmation ;
    }
</script>

This one works on Firefox, Chrome, Internet Explorer(edge), Safari, etc.

If that is not the case let me know

ORACLE convert number to string

This should solve your problem:

select replace(to_char(a, '90D90'),'.00','')
from
(
select 50 a from dual
union
select 50.57 from dual
union
select 5.57 from dual
union
select 0.35 from dual
union
select 0.4 from dual
);

Give a look also as this SQL Fiddle for test.

Load image from resources area of project in C#

I looked at the designer code from one of my projects and noticed it used this notation

myButton.Image = global::MyProjectName.Properties.Resources.max;

where max is the name of the resource I uploaded into the project.

How do I get the parent directory in Python?

GET Parent Directory Path and make New directory (name new_dir)

Get Parent Directory Path

os.path.abspath('..')
os.pardir

Example 1

import os
print os.makedirs(os.path.join(os.path.dirname(__file__), os.pardir, 'new_dir'))

Example 2

import os
print os.makedirs(os.path.join(os.path.dirname(__file__), os.path.abspath('..'), 'new_dir'))

Redirect after Login on WordPress

Based on some of the other answers, I came up with this:

/**
 * Require login on all pages
 */
function so8127453_require_login() {
  if ( ! is_user_logged_in() ) {

    $protocol = $_SERVER['HTTPS'] == 'on' ? 'https://' : 'http://';
    $base = $_SERVER['SERVER_NAME'];
    $uri = $_SERVER['REQUEST_URI'];

    $attempted_accessed_url = $protocol . $base . $uri;
    $login_url = 'https://' . $base . '/wp-login.php?redirect_to=' . $attempted_accessed_url;

    wp_redirect( $login_url );
  }
}
add_action( 'template_redirect', 'so8127453_require_login' );

Redirects all traffic to a login-page. And then to the attempted access URL afterwards.

How to style a div to have a background color for the entire width of the content, and not just for the width of the display?

The inline-block display style seems to do what you want. Note that the <nobr> tag is deprecated, and should not be used. Non-breaking white space is doable in CSS. Here's how I would alter your example style rules:

div { display: inline-block; white-space: nowrap; }
.success { background-color: #ccffcc; }

Alter your stylesheet, remove the <nobr> tags from your source, and give it a try. Note that display: inline-block does not work in every browser, though it tends to only be problematic in older browsers (newer versions should support it to some degree). My personal opinion is to ignore coding for broken browsers. If your code is standards compliant, it should work in all of the major, modern browsers. Anyone still using IE6 (or earlier) deserves the pain. :-)

How to disable button in React.js

this.input is undefined until the ref callback is called. Try setting this.input to some initial value in your constructor.

From the React docs on refs, emphasis mine:

the callback will be executed immediately after the component is mounted or unmounted

How do I call Objective-C code from Swift?

See Apple's guide to Using Swift with Cocoa and Objective-C. This guide covers how to use Objective-C and C code from Swift and vice versa and has recommendations for how to convert a project or mix and match Objective-C/C and Swift parts in an existing project.

The compiler automatically generates Swift syntax for calling C functions and Objective-C methods. As seen in the documentation, this Objective-C:

UITableView *myTableView = [[UITableView alloc] initWithFrame:CGRectZero style:UITableViewStyleGrouped];

turns into this Swift code:

let myTableView: UITableView = UITableView(frame: CGRectZero, style: .Grouped)

Xcode also does this translation on the fly — you can use Open Quickly while editing a Swift file and type an Objective-C class name, and it'll take you to a Swift-ified version of the class header. (You can also get this by cmd-clicking on an API symbol in a Swift file.) And all the API reference documentation in the iOS 8 and OS X v10.10 (Yosemite) developer libraries is visible in both Objective-C and Swift forms (e.g. UIView).

Node - how to run app.js?

The code downloaded may require you to install dependencies first. Try commands(in app.js directory): npm install then node app.js. This should install dependencies and then start the app.

Convert NSArray to NSString in Objective-C

I recently found a really good tutorial on Objective-C Strings:

http://ios-blog.co.uk/tutorials/objective-c-strings-a-guide-for-beginners/

And I thought that this might be of interest:

If you want to split the string into an array use a method called componentsSeparatedByString to achieve this:

NSString *yourString = @"This is a test string";
    NSArray *yourWords = [myString componentsSeparatedByString:@" "];

    // yourWords is now: [@"This", @"is", @"a", @"test", @"string"]

if you need to split on a set of several different characters, use NSString’s componentsSeparatedByCharactersInSet:

NSString *yourString = @"Foo-bar/iOS-Blog";
NSArray *yourWords = [myString componentsSeparatedByCharactersInSet:
                  [NSCharacterSet characterSetWithCharactersInString:@"-/"]
                ];

// yourWords is now: [@"Foo", @"bar", @"iOS", @"Blog"]

Note however that the separator string can’t be blank. If you need to separate a string into its individual characters, just loop through the length of the string and convert each char into a new string:

NSMutableArray *characters = [[NSMutableArray alloc] initWithCapacity:[myString length]];
for (int i=0; i < [myString length]; i++) {
    NSString *ichar  = [NSString stringWithFormat:@"%c", [myString characterAtIndex:i]];
    [characters addObject:ichar];
}

How to include route handlers in multiple files in Express?

If you want a separate .js file to better organize your routes, just create a variable in the app.js file pointing to its location in the filesystem:

var wf = require(./routes/wf);

then,

app.get('/wf', wf.foo );

where .foo is some function declared in your wf.js file. e.g

// wf.js file 
exports.foo = function(req,res){

          console.log(` request object is ${req}, response object is ${res} `);

}

C++ - How to append a char to char*?

The function name does not reflect the semantic of the function. In fact you do not append a character. You create a new character array that contains the original array plus the given character. So if you indeed need a function that appends a character to a character array I would write it the following way

bool AppendCharToCharArray( char *array, size_t n, char c )
{
    size_t sz = std::strlen( array );

    if ( sz + 1 < n ) 
    {
        array[sz] = c;
        array[sz + 1] = '\0';
    }       

    return ( sz + 1 < n );
} 

If you need a function that will contain a copy of the original array plus the given character then it could look the following way

char * CharArrayPlusChar( const char *array, char c )
{
    size_t sz = std::strlen( array );
    char *s = new char[sz + 2];

    std::strcpy( s, array );
    s[sz] = c;
    s[sz + 1] = '\0';

    return ( s );
} 

Getting PEAR to work on XAMPP (Apache/MySQL stack on Windows)

If you are using the portable XAMPP installation and Windows 7, and, like me have the version after they removed the XAMPP shell from the control panel none of the suggested answers here will do you much good as the packages will not install.

The problem is with the config file. I found the correct settings after a lot of trial and error.

Simply pull up a command window in the \xampp\php directory and run

pear config-set doc_dir :\xampp\php\docs\PEAR
pear config-set cfg_dir :\xampp\php\cfg
pear config-set data_dir :\xampp\php\data\PEAR
pear config-set test_dir :\xampp\php\tests
pear config-set www_dir :\xampp\php\www

you will want to replace the ':' with the actual drive letter that your portable drive is running on at the moment. Unfortunately, this needs to be done any time this drive letter changes, but it did get the module I needed installed.

Hello World in Python

Unfortunately the xkcd comic isn't completely up to date anymore.

https://imgs.xkcd.com/comics/python.png

Since Python 3.0 you have to write:

print("Hello world!")

And someone still has to write that antigravity library :(

How do I rotate text in css?

You can use like this...

<div id="rot">hello</div>

#rot
{
   -webkit-transform: rotate(-90deg); 
   -moz-transform: rotate(-90deg);    
    width:100px;
}

Have a look at this fiddle:http://jsfiddle.net/anish/MAN4g/

"java.lang.OutOfMemoryError : unable to create new native Thread"

First of all I wouldn't blame that much the OS/VM.. rather the developer who wrote the code that creates sooo many Threads. Basically somewhere in your code (or 3rd party) a lot of threads are created without control.

Carefully review the stacktraces/code and control the number of threads that get created. Normally your app shouldn't need a large amount of threads, if it does it's a different problem.

How to restore to a different database in sql server?

You can create a new db then use the "Restore Wizard" enabling the Overwrite option or;

View the content;

RESTORE FILELISTONLY FROM DISK='c:\your.bak'

note the logical names of the .mdf & .ldf from the results, then;

RESTORE DATABASE MyTempCopy FROM DISK='c:\your.bak'
WITH 
   MOVE 'LogicalNameForTheMDF' TO 'c:\MyTempCopy.mdf',
   MOVE 'LogicalNameForTheLDF' TO 'c:\MyTempCopy_log.ldf'

To create the database MyTempCopy with the contents of your.bak.

Example (restores a backup of a db called 'creditline' to 'MyTempCopy';

RESTORE FILELISTONLY FROM DISK='e:\mssql\backup\creditline.bak'

>LogicalName
>--------------
>CreditLine
>CreditLine_log

RESTORE DATABASE MyTempCopy FROM DISK='e:\mssql\backup\creditline.bak'
WITH 
   MOVE 'CreditLine' TO 'e:\mssql\MyTempCopy.mdf',
   MOVE 'CreditLine_log' TO 'e:\mssql\MyTempCopy_log.ldf'

>RESTORE DATABASE successfully processed 186 pages in 0.010 seconds (144.970 MB/sec).

How to find specific lines in a table using Selenium?

(.//*[table-locator])[n]

where n represents the specific line.

Read file content from S3 bucket with boto3

You might also consider the smart_open module, which supports iterators:

from smart_open import smart_open

# stream lines from an S3 object
for line in smart_open('s3://mybucket/mykey.txt', 'rb'):
    print(line.decode('utf8'))

and context managers:

with smart_open('s3://mybucket/mykey.txt', 'rb') as s3_source:
    for line in s3_source:
         print(line.decode('utf8'))

    s3_source.seek(0)  # seek to the beginning
    b1000 = s3_source.read(1000)  # read 1000 bytes

Find smart_open at https://pypi.org/project/smart_open/

Doctrine findBy 'does not equal'

Based on the answer from Luis, you can do something more like the default findBy method.

First, create a default repository class that is going to be used by all your entities.

/* $config is the entity manager configuration object. */
$config->setDefaultRepositoryClassName( 'MyCompany\Repository' );

Or you can edit this in config.yml

doctrine: orm: default_repository_class: MyCompany\Repository

Then:

<?php

namespace MyCompany;

use Doctrine\ORM\EntityRepository;

class Repository extends EntityRepository {

    public function findByNot( array $criteria, array $orderBy = null, $limit = null, $offset = null )
    {
        $qb = $this->getEntityManager()->createQueryBuilder();
        $expr = $this->getEntityManager()->getExpressionBuilder();

        $qb->select( 'entity' )
            ->from( $this->getEntityName(), 'entity' );

        foreach ( $criteria as $field => $value ) {
            // IF INTEGER neq, IF NOT notLike
            if($this->getEntityManager()->getClassMetadata($this->getEntityName())->getFieldMapping($field)["type"]=="integer") {
                $qb->andWhere( $expr->neq( 'entity.' . $field, $value ) );
            } else {
                $qb->andWhere( $expr->notLike( 'entity.' . $field, $qb->expr()->literal($value) ) );
            }
        }

        if ( $orderBy ) {

            foreach ( $orderBy as $field => $order ) {

                $qb->addOrderBy( 'entity.' . $field, $order );
            }
        }

        if ( $limit )
            $qb->setMaxResults( $limit );

        if ( $offset )
            $qb->setFirstResult( $offset );

        return $qb->getQuery()
            ->getResult();
    }

}

The usage is the same than the findBy method, example:

$entityManager->getRepository( 'MyRepo' )->findByNot(
    array( 'status' => Status::STATUS_DISABLED )
);

Change values on matplotlib imshow() graph axis

I had a similar problem and google was sending me to this post. My solution was a bit different and less compact, but hopefully this can be useful to someone.

Showing your image with matplotlib.pyplot.imshow is generally a fast way to display 2D data. However this by default labels the axes with the pixel count. If the 2D data you are plotting corresponds to some uniform grid defined by arrays x and y, then you can use matplotlib.pyplot.xticks and matplotlib.pyplot.yticks to label the x and y axes using the values in those arrays. These will associate some labels, corresponding to the actual grid data, to the pixel counts on the axes. And doing this is much faster than using something like pcolor for example.

Here is an attempt at this with your data:

import matplotlib.pyplot as plt

# ... define 2D array hist as you did

plt.imshow(hist, cmap='Reds')
x = np.arange(80,122,2) # the grid to which your data corresponds
nx = x.shape[0]
no_labels = 7 # how many labels to see on axis x
step_x = int(nx / (no_labels - 1)) # step between consecutive labels
x_positions = np.arange(0,nx,step_x) # pixel count at label position
x_labels = x[::step_x] # labels you want to see
plt.xticks(x_positions, x_labels)
# in principle you can do the same for y, but it is not necessary in your case

What is the technology behind wechat, whatsapp and other messenger apps?

WhatsApp has chosen Erlang a language built for writing scalable applications that are designed to withstand errors. Erlang uses an abstraction called the Actor model for it's concurrency - http://en.wikipedia.org/wiki/Actor_(programming_language) Instead of the more traditional shared memory approach, actors communicate by sending each other messages. Actors unlike threads are designed to be lightweight. Actors could be on the same machine or on different machines and the message passing abstractions works for both. A simple implementation of WhatsApp could be: Each user/device is represented as an actor. This actor is responsible for handling the inbox of the user, how it gets serialized to disk, the messages that the user sends and the messages that the user receives. Let's assume that Alice and Bob are friends on WhatsApp. So there is an an Alice actor and a Bob actor.

Let's trace a series of messages flowing back and forth:

Alice decides to message Bob. Alice's phone establishes a connection to the WhatsApp server and it is established that this connection is definitely from Alice's phone. Alice now sends via TCP the following message: "For Bob: A giant monster is attacking the Golden Gate Bridge". One of the WhatsApp front end server deserializes this message and delivers this message to the actor called Alice.

Alice the actor decides to serialize this and store it in a file called "Alice's Sent Messages", stored on a replicated file system to prevent data loss due to unpredictable monster rampage. Alice the actor then decides to forward this message to Bob the actor by passing it a message "Msg1 from Alice: A giant monster is attacking the Golden Gate Bridge". Alice the actor can retry with exponential back-off till Bob the actor acknowledges receiving the message.

Bob the actor eventually receives the message from (2) and decides to store this message in a file called "Bob's Inbox". Once it has stored this message durably Bob the actor will acknowledge receiving the message by sending Alice the actor a message of it's own saying "I received Msg1". Alice the actor can now stop it's retry efforts. Bob the actor then checks to see if Bob's phone has an active connection to the server. It does and so Bob the actor streams this message to the device via TCP.

Bob sees this message and replies with "For Alice: Let's create giant robots to fight them". This is now received by Bob the actor as outlined in Step 1. Bob the actor then repeats Step 2 and 3 to make sure Alice eventually receives the idea that will save mankind.

WhatsApp actually uses the XMPP protocol instead of the vastly superior protocol that I outlined above, but you get the point.

Python script header


I'd suggest 3 things in the beginning of your script:

First, as already being said use environment:

#!/usr/bin/env python

Second, set your encoding:

# -*- coding: utf-8 -*-

Third, set some doc string:

"""This is a awesome
    python script!"""

And for sure I would use " " (4 spaces) for ident.
Final header will look like:

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""This is a awesome
        python script!"""


Best wishes and happy coding.

ASP.NET MVC on IIS 7.5

One more thing to make sure you have is the following set in your web.config:

<system.webServer>
    <modules runAllManagedModulesForAllRequests="true"/> 
</system.webServer>

How do I create and read a value from cookie?

Simple way to read cookies in ES6.

function getCookies() {
    var cookies = {};
    for (let cookie of document.cookie.split('; ')) {
        let [name, value] = cookie.split("=");
        cookies[name] = decodeURIComponent(value);
    }
    console.dir(cookies);
}

Select rows where column is null

You want to know if the column is null

select * from foo where bar is null

If you want to check for some value not equal to something and the column also contains null values you will not get the columns with null in it

does not work:

select * from foo where bar <> 'value'

does work:

select * from foo where bar <> 'value' or bar is null

in Oracle (don't know on other DBMS) some people use this

select * from foo where NVL(bar,'n/a') <> 'value'

if I read the answer from tdammers correctly then in MS SQL Server this is like that

select * from foo where ISNULL(bar,'n/a') <> 'value'

in my opinion it is a bit of a hack and the moment 'value' becomes a variable the statement tends to become buggy if the variable contains 'n/a'.

Select multiple rows with the same value(s)

This may work for you:

select t1.*
from table t1
join (select t2.Chromosome, t2.Locus
    from table2
    group by t2.Chromosome, t2.Locus
    having count(*) > 1) u on u.Chromosome = t1.Chromosome and u.Locus = t1.Locus

Python causing: IOError: [Errno 28] No space left on device: '../results/32766.html' on disk with lots of space

It turns out the best solution for me here was to just reformat the drive. Once reformatted all these problems were no longer problems.

PHP - Indirect modification of overloaded property

Though I am very late in this discussion, I thought this may be useful for some one in future.

I had faced similar situation. The easiest workaround for those who doesn't mind unsetting and resetting the variable is to do so. I am pretty sure the reason why this is not working is clear from the other answers and from the php.net manual. The simplest workaround worked for me is

Assumption:

  1. $object is the object with overloaded __get and __set from the base class, which I am not in the freedom to modify.
  2. shippingData is the array I want to modify a field of for e.g. :- phone_number

 

// First store the array in a local variable.
$tempShippingData = $object->shippingData;

unset($object->shippingData);

$tempShippingData['phone_number'] = '888-666-0000' // what ever the value you want to set

$object->shippingData = $tempShippingData; // this will again call the __set and set the array variable

unset($tempShippingData);

Note: this solution is one of the quick workaround possible to solve the problem and get the variable copied. If the array is too humungous, it may be good to force rewrite the __get method to return a reference rather expensive copying of big arrays.

Why is Github asking for username/password when following the instructions on screen and pushing a new repo?

Don't use HTTP use SSH instead

change

https://github.com/WEMP/project-slideshow.git 

to

[email protected]:WEMP/project-slideshow.git

you can do it in .git/config file

How to change DataTable columns order

This is based off of "default locale"'s answer but it will remove invalid column names prior to setting ordinal. This is because if you accidentally send an invalid column name then it would fail and if you put a check to prevent it from failing then the index would be wrong since it would skip indices wherever an invalid column name was passed in.

public static class DataTableExtensions
{
    /// <summary>
    /// SetOrdinal of DataTable columns based on the index of the columnNames array. Removes invalid column names first.
    /// </summary>
    /// <param name="table"></param>
    /// <param name="columnNames"></param>
    /// <remarks> http://stackoverflow.com/questions/3757997/how-to-change-datatable-colums-order</remarks>
    public static void SetColumnsOrder(this DataTable dtbl, params String[] columnNames)
    {
        List<string> listColNames = columnNames.ToList();

        //Remove invalid column names.
        foreach (string colName in columnNames)
        {
            if (!dtbl.Columns.Contains(colName))
            {
                listColNames.Remove(colName);
            }
        }

        foreach (string colName in listColNames)
        {
            dtbl.Columns[colName].SetOrdinal(listColNames.IndexOf(colName));
        }
}

Convert a numpy.ndarray to string(or bytes) and convert it back to numpy.ndarray

I know, I am late but here is the correct way of doing it. using base64. This technique will convert the array to string.

import base64
import numpy as np
random_array = np.random.randn(32,32)
string_repr = base64.binascii.b2a_base64(random_array).decode("ascii")
array = np.frombuffer(base64.binascii.a2b_base64(string_repr.encode("ascii"))) 

For array to string

Convert binary data to a line of ASCII characters in base64 coding and decode to ASCII to get string repr.

For string to array

First, encode the string in ASCII format then Convert a block of base64 data back to binary and return the binary data.

Is there a job scheduler library for node.js?

node-schedule A cron-like and not-cron-like job scheduler for Node.

Linq UNION query to select two elements

EDIT:

Ok I found why the int.ToString() in LINQtoEF fails, please read this post: Problem with converting int to string in Linq to entities

This works on my side :

        List<string> materialTypes = (from u in result.Users
                                      select u.LastName)
                       .Union(from u in result.Users
                               select SqlFunctions.StringConvert((double) u.UserId)).ToList();

On yours it should be like this:

    IList<String> materialTypes = ((from tom in context.MaterialTypes
                                       where tom.IsActive == true
                                       select tom.Name)
                                       .Union(from tom in context.MaterialTypes
                                       where tom.IsActive == true
                                       select SqlFunctions.StringConvert((double)tom.ID))).ToList();

Thanks, i've learnt something today :)

How can I check if a view is visible or not in Android?

You'd use the corresponding method getVisibility(). Method names prefixed with 'get' and 'set' are Java's convention for representing properties. Some language have actual language constructs for properties but Java isn't one of them. So when you see something labeled 'setX', you can be 99% certain there's a corresponding 'getX' that will tell you the value.

Adding ASP.NET MVC5 Identity Authentication to an existing project

I recommend IdentityServer.This is a .NET Foundation project and covers many issues about authentication and authorization.

Overview

IdentityServer is a .NET/Katana-based framework and hostable component that allows implementing single sign-on and access control for modern web applications and APIs using protocols like OpenID Connect and OAuth2. It supports a wide range of clients like mobile, web, SPAs and desktop applications and is extensible to allow integration in new and existing architectures.

For more information, e.g.

  • support for MembershipReboot and ASP.NET Identity based user stores
  • support for additional Katana authentication middleware (e.g. Google, Twitter, Facebook etc)
  • support for EntityFramework based persistence of configuration
  • support for WS-Federation
  • extensibility

check out the documentation and the demo.

How can I replace a regex substring match in Javascript?

I would get the part before and after what you want to replace and put them either side.

Like:

var str   = 'asd-0.testing';
var regex = /(asd-)\d(\.\w+)/;

var matches = str.match(regex);

var result = matches[1] + "1" + matches[2];

// With ES6:
var result = `${matches[1]}1${matches[2]}`;

Check if string ends with certain pattern

    String input1 = "This.is.a.great.place.too.work.";
    String input2 = "This/is/a/great/place/too/work/";
    String input3 = "This,is,a,great,place,too,work,";
    String input4 = "This.is.a.great.place.too.work.hahahah";
    String input5 = "This/is/a/great/place/too/work/hahaha";
    String input6 = "This,is,a,great,place,too,work,hahahha";
    
    String regEx = ".*work[.,/]";
    
    System.out.println(input1.matches(regEx)); // true
    System.out.println(input2.matches(regEx)); // true
    System.out.println(input3.matches(regEx)); // true
    System.out.println(input4.matches(regEx)); // false
    System.out.println(input5.matches(regEx)); // false
    System.out.println(input6.matches(regEx)); // false

What is the Python equivalent of static variables inside a function?

Instead of creating a function having a static local variable, you can always create what is called a "function object" and give it a standard (non-static) member variable.

Since you gave an example written C++, I will first explain what a "function object" is in C++. A "function object" is simply any class with an overloaded operator(). Instances of the class will behave like functions. For example, you can write int x = square(5); even if square is an object (with overloaded operator()) and not technically not a "function." You can give a function-object any of the features that you could give a class object.

# C++ function object
class Foo_class {
    private:
        int counter;     
    public:
        Foo_class() {
             counter = 0;
        }
        void operator() () {  
            counter++;
            printf("counter is %d\n", counter);
        }     
   };
   Foo_class foo;

In Python, we can also overload operator() except that the method is instead named __call__:

Here is a class definition:

class Foo_class:
    def __init__(self): # __init__ is similair to a C++ class constructor
        self.counter = 0
        # self.counter is like a static member
        # variable of a function named "foo"
    def __call__(self): # overload operator()
        self.counter += 1
        print("counter is %d" % self.counter);
foo = Foo_class() # call the constructor

Here is an example of the class being used:

from foo import foo

for i in range(0, 5):
    foo() # function call

The output printed to the console is:

counter is 1
counter is 2
counter is 3
counter is 4
counter is 5

If you want your function to take input arguments, you can add those to __call__ as well:

# FILE: foo.py - - - - - - - - - - - - - - - - - - - - - - - - -

class Foo_class:
    def __init__(self):
        self.counter = 0
    def __call__(self, x, y, z): # overload operator()
        self.counter += 1
        print("counter is %d" % self.counter);
        print("x, y, z, are %d, %d, %d" % (x, y, z));
foo = Foo_class() # call the constructor

# FILE: main.py - - - - - - - - - - - - - - - - - - - - - - - - - - - - 

from foo import foo

for i in range(0, 5):
    foo(7, 8, 9) # function call

# Console Output - - - - - - - - - - - - - - - - - - - - - - - - - - 

counter is 1
x, y, z, are 7, 8, 9
counter is 2
x, y, z, are 7, 8, 9
counter is 3
x, y, z, are 7, 8, 9
counter is 4
x, y, z, are 7, 8, 9
counter is 5
x, y, z, are 7, 8, 9

Replace or delete certain characters from filenames of all files in a folder

I would recommend the rename command for this. Type ren /? at the command line for more help.

How do I unload (reload) a Python module?

It can be especially difficult to delete a module if it is not pure Python.

Here is some information from: How do I really delete an imported module?

You can use sys.getrefcount() to find out the actual number of references.

>>> import sys, empty, os
>>> sys.getrefcount(sys)
9
>>> sys.getrefcount(os)
6
>>> sys.getrefcount(empty)
3

Numbers greater than 3 indicate that it will be hard to get rid of the module. The homegrown "empty" (containing nothing) module should be garbage collected after

>>> del sys.modules["empty"]
>>> del empty

as the third reference is an artifact of the getrefcount() function.

How do I raise the same Exception with a custom message in Python?

Python 3 built-in exceptions have the strerror field:

except ValueError as err:
  err.strerror = "New error message"
  raise err

Shell script - remove first and last quote (") from a variable

If you're using jq and trying to remove the quotes from the result, the other answers will work, but there's a better way. By using the -r option, you can output the result with no quotes.

$ echo '{"foo": "bar"}' | jq '.foo'
"bar"

$ echo '{"foo": "bar"}' | jq -r '.foo'
bar

Using CMake with GNU Make: How can I see the exact commands?

If you use the CMake GUI then swap to the advanced view and then the option is called CMAKE_VERBOSE_MAKEFILE.

How to check if a Java 8 Stream is empty?

Following Stuart's idea, this could be done with a Spliterator like this:

static <T> Stream<T> defaultIfEmpty(Stream<T> stream, Stream<T> defaultStream) {
    final Spliterator<T> spliterator = stream.spliterator();
    final AtomicReference<T> reference = new AtomicReference<>();
    if (spliterator.tryAdvance(reference::set)) {
        return Stream.concat(Stream.of(reference.get()), StreamSupport.stream(spliterator, stream.isParallel()));
    } else {
        return defaultStream;
    }
}

I think this works with parallel Streams as the stream.spliterator() operation will terminate the stream, and then rebuild it as required

In my use-case I needed a default Stream rather than a default value. that's quite easy to change if this is not what you need

Getting new Twitter API consumer and secret keys

Simply go here: https://dev.twitter.com/apps/new Make sure you have logged in with your Twitter account - then create - even if your just entering random (Test) Content - create your app - afterwards you will receive all the data you require :)

JQUERY ajax passing value from MVC View to Controller

Try using the data option of the $.ajax function. More info here.

$('#btnSaveComments').click(function () {
    var comments = $('#txtComments').val();
    var selectedId = $('#hdnSelectedId').val();

    $.ajax({
        url: '<%: Url.Action("SaveComments")%>',
        data: { 'id' : selectedId, 'comments' : comments },
        type: "post",
        cache: false,
        success: function (savingStatus) {
            $("#hdnOrigComments").val($('#txtComments').val());
            $('#lblCommentsNotification').text(savingStatus);
        },
        error: function (xhr, ajaxOptions, thrownError) {
            $('#lblCommentsNotification').text("Error encountered while saving the comments.");
        }
    });
});

Select N random elements from a List<T> in C#

Extending from @ers's answer, if one is worried about possible different implementations of OrderBy, this should be safe:

// Instead of this
YourList.OrderBy(x => rnd.Next()).Take(5)

// Temporarily transform 
YourList
    .Select(v => new {v, i = rnd.Next()}) // Associate a random index to each entry
    .OrderBy(x => x.i).Take(5) // Sort by (at this point fixed) random index 
    .Select(x => x.v); // Go back to enumerable of entry

PHP split alternative?

You can use the easier function preg_match instead, It's better and faster than all of the other ones.

$var = "<tag>Get this var</tag>";
preg_match("/<tag>(.*)<\/tag>/", $var , $new_var);
echo $new_var['1']; 

Output: Get this var

Use table row coloring for cells in Bootstrap

You can override the default css rules with this:

.table tbody tr > td.success {
  background-color: #dff0d8 !important;
}

.table tbody tr > td.error {
  background-color: #f2dede !important;
}

.table tbody tr > td.warning {
  background-color: #fcf8e3 !important;
}

.table tbody tr > td.info {
  background-color: #d9edf7 !important;
}

.table-hover tbody tr:hover > td.success {
  background-color: #d0e9c6 !important;
}

.table-hover tbody tr:hover > td.error {
  background-color: #ebcccc !important;
}

.table-hover tbody tr:hover > td.warning {
  background-color: #faf2cc !important;
}

.table-hover tbody tr:hover > td.info {
  background-color: #c4e3f3 !important;
}

!important is needed as bootstrap actually colours the cells individually (afaik it's not possible to just apply background-color to a tr). I couldn't find any colour variables in my version of bootstrap but that's the basic idea anyway.

How can I require at least one checkbox be checked before a form can be submitted?

You can either do this on a PHP level or on a Javascript level. If you use Javascript, and/or JQuery, you can check and validate if all the checkboxes are checked with a selector...

Jquery also offers several validation libraries. Check out: http://jqueryvalidation.org/

The problem with using Javascript to validate is that it may be bypassed so it is wise to check on the server too.

Example using PHP and assuming you are calling a PO

<?php
    if( $_GET["BoxSelect"] )
 {
     //Process your form here
     // Save to database, send email, redirect...
} else {

     // Return an error and do not anything
     echo "Checkbox is missing"; 


     exit();
 }
?>

How to preview git-pull without doing fetch?

I may be late to the party, but this is something which bugged me for too long. In my experience, I would rather want to see which changes are pending than update my working copy and deal with those changes.

This goes in the ~/.gitconfig file:

[alias]
        diffpull=!git fetch && git diff HEAD..@{u}

It fetches the current branch, then does a diff between the working copy and this fetched branch. So you should only see the changes that would come with git pull.

Is there a function to copy an array in C/C++?

You can use the memcpy(),

void * memcpy ( void * destination, const void * source, size_t num );

memcpy() copies the values of num bytes from the location pointed by source directly to the memory block pointed by destination.

If the destination and source overlap, then you can use memmove().

void * memmove ( void * destination, const void * source, size_t num );

memmove() copies the values of num bytes from the location pointed by source to the memory block pointed by destination. Copying takes place as if an intermediate buffer were used, allowing the destination and source to overlap.

Bootstrap: add margin/padding space between columns

Super easy with flexbox. Leave room for some space by changing the columns to col-md-5

<div class="row widgets">
    <div class="text-center col-md-5">
        Widget 1
    </div>
    <div class="text-center col-md-5">
        Widget 2
    </div>
</div>

CSS

.widgets {
    display: flex;
    justify-content: space-around;
}

Can someone explain how to implement the jQuery File Upload plugin?

it's 2021 and here's a fantastically easy plugin to upload anything:

https://pqina.nl/filepond/?ref=pqina

add your element:

<input type="file" 
class="filepond"
name="filepond" 
multiple 
data-allow-reorder="true"
data-max-file-size="3MB"
data-max-files="3">

Register any additional plugins:

  FilePond.registerPlugin(
FilePondPluginImagePreview,  
FilePondPluginImageExifOrientation,  
FilePondPluginFileValidateSize,  
FilePondPluginImageEdit);

Then wire in the element:

// Select the file input and use 
// create() to turn it into a pond
FilePond.create(
  document.querySelector('input'),

  // Use Doka.js as image editor
  imageEditEditor: Doka.create({
    utils: ['crop', 'filter', 'color']
  })
);

I use this with the additional Doka image editor to upload and transform images at https://www.yoodu.co.uk

crazy simple to setup and the guys who run it are great at support.

As you can tell I'm a fanboy.

Root element is missing

Make sure you XML looks like this:

<?xml version="1.0" encoding="utf-8"?>
<rootElement>
...
</rootElement>

Also, a blank XML file will return the same Root elements is missing exception. Each XML file must have a root element / node which encloses all the other elements.

How can I create an object based on an interface file definition in TypeScript?

If you are creating the "modal" variable elsewhere, and want to tell TypeScript it will all be done, you would use:

declare const modal: IModal;

If you want to create a variable that will actually be an instance of IModal in TypeScript you will need to define it fully.

const modal: IModal = {
    content: '',
    form: '',
    href: '',
    $form: null,
    $message: null,
    $modal: null,
    $submits: null
};

Or lie, with a type assertion, but you'll lost type safety as you will now get undefined in unexpected places, and possibly runtime errors, when accessing modal.content and so on (properties that the contract says will be there).

const modal = {} as IModal;

Example Class

class Modal implements IModal {
    content: string;
    form: string;
    href: string;
    $form: JQuery;
    $message: JQuery;
    $modal: JQuery;
    $submits: JQuery;
}

const modal = new Modal();

You may think "hey that's really a duplication of the interface" - and you are correct. If the Modal class is the only implementation of the IModal interface you may want to delete the interface altogether and use...

const modal: Modal = new Modal();

Rather than

const modal: IModal = new Modal();

Hexadecimal value 0x00 is a invalid character

To add to Sonz's answer above, following worked for us.

//Instead of 
XmlString.Replace("&#x0;", "[0x00]");
// use this
XmlString.Replace("\x00", "[0x00]");

How to call Stored Procedure in Entity Framework 6 (Code-First)?

I found that calling of stored procedures in code-first approach is not convenient.

I prefer to use Dapper instead.

The following code was written with Entity Framework:

var clientIdParameter = new SqlParameter("@ClientId", 4);

var result = context.Database
.SqlQuery<ResultForCampaign>("GetResultsForCampaign @ClientId", clientIdParameter)
.ToList();

The following code was written with Dapper:

return Database.Connection.Query<ResultForCampaign>(
            "GetResultsForCampaign ",
            new
            {
                ClientId = 4
            },
            commandType: CommandType.StoredProcedure);
    

I believe the second piece of code is simpler to understand.

Installing Python 3 on RHEL

It is easy to install it manually:

  1. Download (there may be newer releases on Python.org):

    $ wget https://www.python.org/ftp/python/3.4.3/Python-3.4.3.tar.xz
    
  2. Unzip

    $ tar xf Python-3.* 
    $ cd Python-3.*
    
  3. Prepare compilation

    $ ./configure
    
  4. Build

    $ make
    
  5. Install

    $ make install
    

    OR if you don't want to overwrite the python executable (safer, at least on some distros yum needs python to be 2.x, such as for RHEL6) - you can install python3.* as a concurrent instance to the system default with an altinstall:

    $ make altinstall
    

Now if you want an alternative installation directory, you can pass --prefix to the configurecommand.

Example: for 'installing' Python in /opt/local, just add --prefix=/opt/local.

After the make install step: In order to use your new Python installation, it could be, that you still have to add the [prefix]/bin to the $PATH and [prefix]/lib to the $LD_LIBRARY_PATH (depending of the --prefix you passed)

How to get maximum value from the Collection (for example ArrayList)?

public int getMax(ArrayList list){
    int max = Integer.MIN_VALUE;
    for(int i=0; i<list.size(); i++){
        if(list.get(i) > max){
            max = list.get(i);
        }
    }
    return max;
}

From my understanding, this is basically what Collections.max() does, though they use a comparator since lists are generic.

How to detect the physical connected state of a network cable/connector?

Some precisions and tricks

  1. I do all this as normal user (not root)

  2. Grab infos from dmesg

    Using dmesg is one of the 1st things to do for inquiring current state of system:

    dmesg | sed '/eth.*Link is/h;${x;p};d'
    

    could answer something like:

    [936536.904154] e1000e: eth0 NIC Link is Down
    

    or

    [936555.596870] e1000e: eth0 NIC Link is Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
    

    depending on state, message could vary depending on hardware and drivers used.

    Nota: this could by written dmesg|grep eth.*Link.is|tail -n1 but I prefer using sed.

    dmesg | sed '/eth.*Link is/h;${x;s/^.*Link is //;p};d'
    Up 100 Mbps Full Duplex, Flow Control: Rx/Tx
    
    dmesg | sed '/eth.*Link is/h;${x;s/^.*Link is //;p};d'
    Down
    
  3. Test around /sys pseudo filesystem

    Reading or writting under /syscould break your system, especially if run as root! You've been warned ;-)

    This is a pooling method, not a real event tracking.

    cd /tmp
    grep -H . /sys/class/net/eth0/* 2>/dev/null >ethstate
    while ! read -t 1;do
        grep -H . /sys/class/net/eth0/* 2>/dev/null |
            diff -u ethstate - |
            tee >(patch -p0) |
            grep ^+
      done
    

    Could render something like (once you've unplugged and plugged back, depending ):

    +++ -   2016-11-18 14:18:29.577094838 +0100
    +/sys/class/net/eth0/carrier:0
    +/sys/class/net/eth0/carrier_changes:9
    +/sys/class/net/eth0/duplex:unknown
    +/sys/class/net/eth0/operstate:down
    +/sys/class/net/eth0/speed:-1
    +++ -   2016-11-18 14:18:48.771581903 +0100
    +/sys/class/net/eth0/carrier:1
    +/sys/class/net/eth0/carrier_changes:10
    +/sys/class/net/eth0/duplex:full
    +/sys/class/net/eth0/operstate:up
    +/sys/class/net/eth0/speed:100
    

    (Hit Enter to exit loop)

    Nota: This require patch to be installed.

  4. In fine, there must already be something about this...

    Depending on Linux Installation, you could add if-up and if-down scripts to be able to react to this kind of events.

    On Debian based (like Ubuntu), you could store your scripts into

    /etc/network/if-down.d
    /etc/network/if-post-down.d
    /etc/network/if-pre-up.d
    /etc/network/if-up.d
    

    see man interfaces for more infos.

nodejs module.js:340 error: cannot find module

EDIT: This answer is outdated. With things like Yarn and NPM 5's lockfiles it is now easier to ensure you're dependencies are correct on platforms like Heroku

I had a similar issue related to node_modules being modified somehow locally but the change was not reflect on Heroku, causing my app to crash. It's relatively easy fix if this is your issue:

# Remove node_modules
rm -fr node_modules

# Reinstall packages
npm i

# Commit changes
git add node_modules
git commit -m 'Fix node_modules dependencies.'
git push heroku master

Hope that helps for others with a similar issue.

JQUERY: Uncaught Error: Syntax error, unrecognized expression

This can also happen in safari if you try a selector with a missing ], for example

$('select[name="something"')

but interestingly, this same jquery selector with a missing bracket will work in chrome.

Laravel: Get base url

you can get it from Request, at laravel 5

request()->getSchemeAndHttpHost();

How can I get Docker Linux container information from within the container itself?

awk -F'[:/]' '(($4 == "docker") && (lastId != $NF)) { lastId = $NF; print $NF; }' /proc/self/cgroup

How to change the background-color of jumbrotron?

You don't necessarily have to use custom CSS (or even worse inline CSS), in Bootstrap 4 you can use the utility classes for colors, like:

<div class="jumbotron bg-dark text-white">
...

And if you need other colors than the default ones, just add additional bg-classes using the same naming convention. This keeps the code neat and understandable.

You might also need to set text-white on child-elements inside the jumbotron, like headings.

Sequence Permission in Oracle

Just another bit. in some case i found no result on all_tab_privs! i found it indeed on dba_tab_privs. I think so that this last table is better to check for any grant available on an object (in case of impact analysis). The statement becomes:

    select * from dba_tab_privs where table_name = 'sequence_name';

Eclipse error, "The selection cannot be launched, and there are no recent launches"

Eclipse can't work out what you want to run and since you've not run anything before, it can't try re-running that either.

Instead of clicking the green 'run' button, click the dropdown next to it and chose Run Configurations. On the Android tab, make sure it's set to your project. In the Target tab, set the tick box and options as appropriate to target your device. Then click Run. Keep an eye on your Console tab in Eclipse - that'll let you know what's going on. Once you've got your run configuration set, you can just hit the green 'run' button next time.

Sometimes getting everything to talk to your device can be problematic to begin with. Consider using an AVD (i.e. an emulator) as alternative, at least to begin with if you have problems. You can easily create one from the menu Window -> Android Virtual Device Manager within Eclipse.

To view the progress of your project being installed and started on your device, check the console. It's a panel within Eclipse with the tabs Problems/Javadoc/Declaration/Console/LogCat etc. It may be minimised - check the tray in the bottom right. Or just use Window/Show View/Console from the menu to make it come to the front. There are two consoles, Android and DDMS - there is a dropdown by its icon where you can switch.

Android: How to get a custom View's height and width?

Don't try to get them inside its constructor. Try Call them in onDraw() method.

Scanner doesn't read whole sentence - difference between next() and nextLine() of scanner class

import java.util.Scanner;
public class Solution {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int i = scan.nextInt();
        double d = scan.nextDouble();
        String s="";
        while(scan.hasNext())
        {
            s=scan.nextLine();
        }

        System.out.println("String: " +s);
        System.out.println("Double: " + d);
        System.out.println("Int: " + i);
    }
}

How to programmatically log out from Facebook SDK 3.0 without using Facebook login/logout button?

Facebook provides two ways to login and logout from an account. One is to use LoginButton and the other is to use LoginManager. LoginButton is just a button which on clicked, the logging in is accomplished. On the other side LoginManager does this on its own. In your case you have use LoginManager to logout automatically.

LoginManager.getInstance().logout() does this work for you.

GlobalConfiguration.Configure() not present after Web API 2 and .NET 4.5.1 migration

GlobalConfiguration.Configure API is available in "Microsoft.AspNet.WebApi.WebHost" version="5.2.3"

and not in "Microsoft.AspNet.WebApi.WebHost" version="4.0.0"

Download a div in a HTML page as pdf using javascript

Content inside a <div class='html-content'>....</div> can be downloaded as pdf with styles using jspdf & html2canvas.

You need to refer both js libraries,

<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jspdf/1.5.3/jspdf.min.js"></script>
<script type="text/javascript" src="https://html2canvas.hertzen.com/dist/html2canvas.js"></script>

Then call below function,

//Create PDf from HTML...
function CreatePDFfromHTML() {
    var HTML_Width = $(".html-content").width();
    var HTML_Height = $(".html-content").height();
    var top_left_margin = 15;
    var PDF_Width = HTML_Width + (top_left_margin * 2);
    var PDF_Height = (PDF_Width * 1.5) + (top_left_margin * 2);
    var canvas_image_width = HTML_Width;
    var canvas_image_height = HTML_Height;

    var totalPDFPages = Math.ceil(HTML_Height / PDF_Height) - 1;

    html2canvas($(".html-content")[0]).then(function (canvas) {
        var imgData = canvas.toDataURL("image/jpeg", 1.0);
        var pdf = new jsPDF('p', 'pt', [PDF_Width, PDF_Height]);
        pdf.addImage(imgData, 'JPG', top_left_margin, top_left_margin, canvas_image_width, canvas_image_height);
        for (var i = 1; i <= totalPDFPages; i++) { 
            pdf.addPage(PDF_Width, PDF_Height);
            pdf.addImage(imgData, 'JPG', top_left_margin, -(PDF_Height*i)+(top_left_margin*4),canvas_image_width,canvas_image_height);
        }
        pdf.save("Your_PDF_Name.pdf");
        $(".html-content").hide();
    });
}

Ref: pdf genration from html canvas and jspdf.

May be this will help someone.

Bind service to activity in Android

If the user backs out, the onDestroy() method will be called. This method is to stop any service that is used in the application. So if you want to continue the service even if the user backs out of the application, just erase onDestroy(). Hope this help.

difference between width auto and width 100 percent

Width auto

The initial width of a block level element like div or p is auto. This makes it expand to occupy all available horizontal space within its containing block. If it has any horizontal padding or border, the widths of those do not add to the total width of the element.

Width 100%

On the other hand, if you specify width:100%, the element’s total width will be 100% of its containing block plus any horizontal margin, padding and border (unless you’ve used box-sizing:border-box, in which case only margins are added to the 100% to change how its total width is calculated). This may be what you want, but most likely it isn’t.

To visualise the difference see this picture:

enter image description here

Source

How can I initialize an ArrayList with all zeroes in Java?

The integer passed to the constructor represents its initial capacity, i.e., the number of elements it can hold before it needs to resize its internal array (and has nothing to do with the initial number of elements in the list).

To initialize an list with 60 zeros you do:

List<Integer> list = new ArrayList<Integer>(Collections.nCopies(60, 0));

If you want to create a list with 60 different objects, you could use the Stream API with a Supplier as follows:

List<Person> persons = Stream.generate(Person::new)
                             .limit(60)
                             .collect(Collectors.toList());

Angular2 equivalent of $document.ready()

I went with this solution so I didn't have to include my custom js code within the component other than the jQuery $.getScript function.

Note: Has a dependency on jQuery. So you will need jQuery and jQuery typings.

I have found this is a good way to get around custom or vendor js files that do not have typings available that way TypeScript doesn't scream at you when you go to start your app.

import { Component,AfterViewInit} from '@angular/core'

@Component({
  selector: 'ssContent',
  templateUrl: 'app/content/content.html',
})
export class ContentComponent implements AfterViewInit  {

  ngAfterViewInit(){
    $.getScript('../js/myjsfile.js');
  }
}

Update Actually in my scenario the OnInit lifecycle event worked better because it prevented the script from loading after the views were loaded, which was the case with ngAfterViewInit, and that cause the view to show incorrect element positions prior to the script loading.

ngOnInit() {
    $.getScript('../js/mimity.js');
  }

how to clear JTable

I think you meant that you want to clear all the cells in the jTable and make it just like a new blank jTable. For an example, if your table is myTable, you can do following.

DefaultTableModel model = new DefaultTableModel();
myTable.setModel(model);

How to square all the values in a vector in R?

This will also work

newData <- data*data

How do I escape a string inside JavaScript code inside an onClick handler?

Declare separate functions in the <head> section and invoke those in your onClick method. If you have lots you could use a naming scheme that numbers them, or pass an integer in in your onClicks and have a big fat switch statement in the function.

npm install error from the terminal

You're likely not in the node directory. Try switching to the directory that you unpacked node to and try running the command there.

Avoid trailing zeroes in printf()

I search the string (starting rightmost) for the first character in the range 1 to 9 (ASCII value 49-57) then null (set to 0) each char right of it - see below:

void stripTrailingZeros(void) { 
    //This finds the index of the rightmost ASCII char[1-9] in array
    //All elements to the left of this are nulled (=0)
    int i = 20;
    unsigned char char1 = 0; //initialised to ensure entry to condition below

    while ((char1 > 57) || (char1 < 49)) {
        i--;
        char1 = sprintfBuffer[i];
    }

    //null chars left of i
    for (int j = i; j < 20; j++) {
        sprintfBuffer[i] = 0;
    }
}

How do I left align these Bootstrap form items?

If you are saying that your problem is how to left align the form labels, see if this helps:
http://jsfiddle.net/panchroma/8gYPQ/

Try changing the text-align left / right in the CSS

.form-horizontal .control-label{
    /* text-align:right; */
    text-align:left;
    background-color:#ffa;
}

Good luck!

How to remove a build from itunes connect?

Dang this is hard. Here is what I did to reject/delete/replace my ios build before it was released. The app was approved how ever I found found a bug I wanted to fix before releasing

  1. I set release to "manual" and saved
  2. I tried to create and app release
  3. got an error message something like "you can only have one release at a time"
  4. where the save button was there was not an option to cancel release
  5. the version of the app is not marked "developer rejected" with a red dot

To replace the bad build I did the following

  1. if you click on the "+ version or platform" to create a new version you will not be be able to create a new iOS version
  2. you need to upload a new build
  3. in your rejected app, select the new build
  4. save
  5. submit for review

How to format a date using ng-model?

I've created a simple directive to enable standard input[type="date"] form elements to work correctly with AngularJS ~1.2.16.

Look here: https://github.com/betsol/angular-input-date

And here's the demo: http://jsfiddle.net/F2LcY/1/

How to POST URL in data of a curl request

Perhaps you don't have to include the single quotes:

curl --request POST 'http://localhost/Service' --data "path=/xyz/pqr/test/&fileName=1.doc"

Update: Reading curl's manual, you could actually separate both fields with two --data:

curl --request POST 'http://localhost/Service' --data "path=/xyz/pqr/test/" --data "fileName=1.doc"

You could also try --data-binary:

curl --request POST 'http://localhost/Service' --data-binary "path=/xyz/pqr/test/" --data-binary "fileName=1.doc"

And --data-urlencode:

curl --request POST 'http://localhost/Service' --data-urlencode "path=/xyz/pqr/test/" --data-urlencode "fileName=1.doc"

How to integrate sourcetree for gitlab

I ended up using GitKraken . I've installed, auth and connected to my repo in 30 seconds.

How to consume REST in Java

Its just a 2 line of code.

import org.springframework.web.client.RestTemplate;

RestTemplate restTemplate = new RestTemplate();
YourBean obj = restTemplate.getForObject("http://gturnquist-quoters.cfapps.io/api/random", YourBean.class);

Ref. Spring.io consuming-rest

Looping from 1 to infinity in Python

If you're doing that in C, then your judgement there is as cloudy as it would be in Python :-)

For a loop that exits on a simple condition check at the start of each iteration, it's more usual (and clearer, in my opinion) to just do that in the looping construct itself. In other words, something like (if you need i after loop end):

int i = 0;
while (! thereIsAReasonToBreak(i)) {
    // do something
    i++;
}

or (if i can be scoped to just the loop):

for (int i = 0; ! thereIsAReasonToBreak(i); ++i) {
    // do something
}

That would translate to the Python equivalent:

i = 0
while not there_is_a_reason_to_break(i):
    # do something
    i += 1

Only if you need to exit in the middle of the loop somewhere (or if your condition is complex enough that it would render your looping statement far less readable) would you need to worry about breaking.

When your potential exit is a simple one at the start of the loop (as it appears to be here), it's usually better to encode the exit into the loop itself.

How to render a DateTime object in a Twig template

It depends on the format you want the date to be shown as.

Static date format

If you want to display a static format, which is the same for all locales (for instance ISO 8601 for an Atom feed), you should use Twig's date filter:

{{ game.gameDate|date('Y-m-d\\TH:i:sP') }}

Which will allways return a datetime in the following format:

2014-05-02T08:55:41Z

The format strings accepted by the date filter are the same as you would use for PHP's date() function. (the only difference is that, as far as I know, you can't use the predefined constants which can be used in the PHP date() function)

Localized dates (and times)

However, since you want to render it in the browser, you'll likely want to show it in a human-readable format, localised for the user's language and location. Instead of doing the localization yourself, you can use the Intl Extension for this (which makes use of PHP's IntlDateFormatter). It provides a filter localizeddate which will output the date and time using a localized format.

localizeddate( date_format, time_format [, locale ] )

Arguments for localizeddate:

  • date_format: One of the format strings (see below)
  • time_format: One of the format strings (see below)
  • locale: (optional) Use this to override the configured locale. Leave this argument out to use the default locale, which can be configured in Symfony's configuration.

(there are more, see the docs for the complete list of possible arguments)

For date_format and time_format you can use one of the following strings:

  • 'none' if you don't want to include this element
  • 'short' for the most abbreviated style (12/13/52 or 3:30pm in an English locale)
  • 'medium' for the medium style (Jan 12, 1952 in an English locale)
  • 'long' for the long style (January 12, 1952 or 3:30:32pm in an English locale)
  • 'full' for the completely specified style (Tuesday, April 12, 1952 AD or 3:30:42pm PST in an English locale)

Example

So, for instance, if you want to display the date in a format equivalent to February 6, 2014 at 10:52 AM, use the following line in your Twig template:

{{ game.gameDate|localizeddate('long', 'short') }}

However, if you use a different locale, the result will be localized for that locale:

  • 6 februari 2014 10:52 for the nl locale;
  • 6 février 2014 10:52 for the fr locale;
  • 6. Februar 2014 10:52 for the de locale; etc.

As you can see, localizeddate does not only translate the month names but also uses the local notations. The English notation puts the date after the month, where Dutch, French and German notations put it before the month. English and German month names start with an uppercase letter, whereas Dutch and French month names are lowercase. And German dates have a dot appended.

Installation / setting the locale

Installation instructions for the Intl extension can be found in this seperate answer.

In LINQ, select all values of property X where X != null

This is adapted from CodesInChaos's extension method. The name is shorter (NotNull) and more importantly, restricts the type (T) to reference types with where T : class.

    public static IEnumerable<T> NotNull<T>(this IEnumerable<T> source) where T : class
    {
        return source.Where(item => item != null);
    }

Full width layout with twitter bootstrap

Because the accepted answer isn't on the same planet as BS3, I'll share what I'm using to achieve nearly full-width capabilities.

First off, this is cheating. It's not really fluid width - but it appears to be - depending on the size of the screen viewing the site.

The problem with BS3 and fluid width sites is that they have taken this "mobile first" approach, which requires that they define every freaking screen width up to what they consider to be desktop (1200px) I'm working on a laptop with a 1900px wide screen - so I end up with 350px on either side of the content at what BS3 thinks is a desktop sized width.

They have defined 10 screen widths (really only 5, but anyway). I don't really feel comfortable changing those, because they are common widths. So, I chose to define some extra widths for BS to choose from when deciding the width of the container class.

The way I use BS is to take all of the Bootstrap provided LESS files, omit the variables.less file to provide my own, and add one of my own to the end to override the things I want to change. Within my less file, I add the following to achieve 2 common screen width settings:

@media screen and (min-width: 1600px) {
    .container {
        max-width: (1600px - @grid-gutter-width);
    }
}
@media screen and (min-width: 1900px) {
    .container {
        max-width: (1900px - @grid-gutter-width);
    }
}

These two settings set the example for what you need to do to achieve different screen widths. Here, you get full width at 1600px, and 1900px. Any less than 1600 - BS falls back to the 1200px width, then to 768px and so forth - down to phone size.

If you have larger to support, just create more @media screen statements like these. If you're building the CSS instead, you'll want to determine what gutter width was used and subtract it from your target screen width.

Update:

Bootstrap 3.0.1 and up (so far) - it's as easy as setting @container-large-desktop to 100%

Javascript onHover event

If you use the JQuery library you can use the .hover() event which merges the mouseover and mouseout event and helps you with the timing and child elements:

$(this).hover(function(){},function(){});

The first function is the start of the hover and the next is the end. Read more at: http://docs.jquery.com/Events/hover

Generic Property in C#

You cannot 'alter' the property syntax this way. What you can do is this:

class Foo
{
    string MyProperty { get; set; }  // auto-property with inaccessible backing field
}

and a generic version would look like this:

class Foo<T>
{
    T MyProperty { get; set; }
}

What is a regex to match ONLY an empty string?

^$ -- regex to accept empty string.And it wont match "/n" or "foobar/n" as you mentioned. You could test this regex on https://www.regextester.com/1924.

If you have your existing regex use or(|) in your regex to match empty string. For example /^[A-Za-z0-9&._ ]+$|^$/

form action with javascript

A form action set to a JavaScript function is not widely supported, I'm surprised it works in FireFox.

The best is to just set form action to your PHP script; if you need to do anything before submission you can just add to onsubmit

Edit turned out you didn't need any extra function, just a small change here:

function validateFormOnSubmit(theForm) {
    var reason = "";
    reason += validateName(theForm.name);
    reason += validatePhone(theForm.phone);
    reason += validateEmail(theForm.emaile);

    if (reason != "") {
        alert("Some fields need correction:\n" + reason);
    } else {
        simpleCart.checkout();
    }
    return false;
}

Then in your form:

<form action="#" onsubmit="return validateFormOnSubmit(this);">

How to give a pattern for new line in grep?

Thanks to @jarno I know about the -z option and I found out that when using GNU grep with the -P option, matching against \n is possible. :)

Example:

grep -zoP 'foo\n\K.*'<<<$'foo\nbar'

Prints bar

Is there a RegExp.escape function in JavaScript?

Most of the expressions here solve single specific use cases.

That's okay, but I prefer an "always works" approach.

function regExpEscape(literal_string) {
    return literal_string.replace(/[-[\]{}()*+!<=:?.\/\\^$|#\s,]/g, '\\$&');
}

This will "fully escape" a literal string for any of the following uses in regular expressions:

  • Insertion in a regular expression. E.g. new RegExp(regExpEscape(str))
  • Insertion in a character class. E.g. new RegExp('[' + regExpEscape(str) + ']')
  • Insertion in integer count specifier. E.g. new RegExp('x{1,' + regExpEscape(str) + '}')
  • Execution in non-JavaScript regular expression engines.

Special Characters Covered:

  • -: Creates a character range in a character class.
  • [ / ]: Starts / ends a character class.
  • { / }: Starts / ends a numeration specifier.
  • ( / ): Starts / ends a group.
  • * / + / ?: Specifies repetition type.
  • .: Matches any character.
  • \: Escapes characters, and starts entities.
  • ^: Specifies start of matching zone, and negates matching in a character class.
  • $: Specifies end of matching zone.
  • |: Specifies alternation.
  • #: Specifies comment in free spacing mode.
  • \s: Ignored in free spacing mode.
  • ,: Separates values in numeration specifier.
  • /: Starts or ends expression.
  • :: Completes special group types, and part of Perl-style character classes.
  • !: Negates zero-width group.
  • < / =: Part of zero-width group specifications.

Notes:

  • / is not strictly necessary in any flavor of regular expression. However, it protects in case someone (shudder) does eval("/" + pattern + "/");.
  • , ensures that if the string is meant to be an integer in the numerical specifier, it will properly cause a RegExp compiling error instead of silently compiling wrong.
  • #, and \s do not need to be escaped in JavaScript, but do in many other flavors. They are escaped here in case the regular expression will later be passed to another program.

If you also need to future-proof the regular expression against potential additions to the JavaScript regex engine capabilities, I recommend using the more paranoid:

function regExpEscapeFuture(literal_string) {
    return literal_string.replace(/[^A-Za-z0-9_]/g, '\\$&');
}

This function escapes every character except those explicitly guaranteed not be used for syntax in future regular expression flavors.


For the truly sanitation-keen, consider this edge case:

var s = '';
new RegExp('(choice1|choice2|' + regExpEscape(s) + ')');

This should compile fine in JavaScript, but will not in some other flavors. If intending to pass to another flavor, the null case of s === '' should be independently checked, like so:

var s = '';
new RegExp('(choice1|choice2' + (s ? '|' + regExpEscape(s) : '') + ')');

What does Html.HiddenFor do?

It creates a hidden input on the form for the field (from your model) that you pass it.

It is useful for fields in your Model/ViewModel that you need to persist on the page and have passed back when another call is made but shouldn't be seen by the user.

Consider the following ViewModel class:

public class ViewModel
{
    public string Value { get; set; }
    public int Id { get; set; }
}

Now you want the edit page to store the ID but have it not be seen:

<% using(Html.BeginForm() { %>
    <%= Html.HiddenFor(model.Id) %><br />
    <%= Html.TextBoxFor(model.Value) %>
<% } %>

This results in the equivalent of the following HTML:

<form name="form1">
    <input type="hidden" name="Id">2</input>
    <input type="text" name="Value" value="Some Text" />
</form>

How to view the SQL queries issued by JPA?

Also, if you're using EclipseLink and want to output the SQL parameter values, you can add this property to your persistence.xml file:

<property name="eclipselink.logging.parameters" value="true"/>

What does ON [PRIMARY] mean?

When you create a database in Microsoft SQL Server you can have multiple file groups, where storage is created in multiple places, directories or disks. Each file group can be named. The PRIMARY file group is the default one, which is always created, and so the SQL you've given creates your table ON the PRIMARY file group.

See MSDN for the full syntax.

Disable all dialog boxes in Excel while running VB script?

Have you tried using the ConflictResolution:=xlLocalSessionChanges parameter in the SaveAs method?

As so:

Public Sub example()
Application.DisplayAlerts = False
Application.EnableEvents = False

For Each element In sArray
    XLSMToXLSX(element)
Next element

Application.DisplayAlerts = False
Application.EnableEvents = False
End Sub

Sub XLSMToXLSX(ByVal file As String)
    Do While WorkFile <> ""
        If Right(WorkFile, 4) <> "xlsx" Then
            Workbooks.Open Filename:=myPath & WorkFile

            Application.DisplayAlerts = False
            Application.EnableEvents = False

            ActiveWorkbook.SaveAs Filename:= _
            modifiedFileName, FileFormat:= _
            xlOpenXMLWorkbook, CreateBackup:=False, _
            ConflictResolution:=xlLocalSessionChanges

            Application.DisplayAlerts = True
            Application.EnableEvents = True

            ActiveWorkbook.Close
        End If
        WorkFile = Dir()
    Loop
End Sub

Get DataKey values in GridView RowCommand

I usually pass the RowIndex via CommandArgument and use it to retrieve the DataKey value I want.

On the Button:

CommandArgument='<%# DataBinder.Eval(Container, "RowIndex") %>'

On the Server Event

int rowIndex = int.Parse(e.CommandArgument.ToString());
string val = (string)this.grid.DataKeys[rowIndex]["myKey"];

Is Java a Compiled or an Interpreted programming language ?

Java is compiled to bytecode, which then goes into the Java VM, which interprets it.

Text that shows an underline on hover

<span class="txt">Some Text</span>

.txt:hover {
    text-decoration: underline;
}

Mock functions in Go

Warning: This might inflate executable file size a little bit and cost a little runtime performance. IMO, this would be better if golang has such feature like macro or function decorator.

If you want to mock functions without changing its API, the easiest way is to change the implementation a little bit:

func getPage(url string) string {
  if GetPageMock != nil {
    return GetPageMock()
  }

  // getPage real implementation goes here!
}

func downloader() {
  if GetPageMock != nil {
    return GetPageMock()
  }

  // getPage real implementation goes here!
}

var GetPageMock func(url string) string = nil
var DownloaderMock func() = nil

This way we can actually mock one function out of the others. For more convenient we can provide such mocking boilerplate:

// download.go
func getPage(url string) string {
  if m.GetPageMock != nil {
    return m.GetPageMock()
  }

  // getPage real implementation goes here!
}

func downloader() {
  if m.GetPageMock != nil {
    return m.GetPageMock()
  }

  // getPage real implementation goes here!
}

type MockHandler struct {
  GetPage func(url string) string
  Downloader func()
}

var m *MockHandler = new(MockHandler)

func Mock(handler *MockHandler) {
  m = handler
}

In test file:

// download_test.go
func GetPageMock(url string) string {
  // ...
}

func TestDownloader(t *testing.T) {
  Mock(&MockHandler{
    GetPage: GetPageMock,
  })

  // Test implementation goes here!

  Mock(new(MockHandler)) // Reset mocked functions
}

Batch File; List files in directory, only filenames?

dir /s/d/a:-d "folderpath*.*" > file.txt

And, lose the /s if you do not need files from subfolders

R - test if first occurrence of string1 is followed by string2

I think it's worth answering the generic question "R - test if string contains string" here.

For that, use the grep function.

# example:
> if(length(grep("ab","aacd"))>0) print("found") else print("Not found")
[1] "Not found"
> if(length(grep("ab","abcd"))>0) print("found") else print("Not found")
[1] "found"

Can't load AMD 64-bit .dll on a IA 32-bit platform

If you are still getting that error after installing the 64 bit JRE, it means that the JVM running Gurobi package is still using the 32 bit JRE.

Check that you have updated the PATH and JAVA_HOME globally and in the command shell that you are using. (Maybe you just need to exit and restart it.)

Check that your command shell runs the right version of Java by running "java -version" and checking that it says it is a 64bit JRE.

If you are launching the example via a wrapper script / batch file, make sure that the script is using the right JRE. Modify as required ...

Detect click inside/outside of element with single event handler

Rather than using the jQuery .parents function (as suggested in the accepted answer), it's better to use .closest for this purpose. As explained in the jQuery api docs, .closest checks the element passed and all its parents, whereas .parents just checks the parents. Consequently, this works:

$(function() {
    $("body").click(function(e) {
        if ($(e.target).closest("#myDiv").length) {
            alert("Clicked inside #myDiv");
        } else { 
            alert("Clicked outside #myDiv");
        }
    });
})

Setting button text via javascript

Use textContent instead of value to set the button text.

Typically the value attribute is used to associate a value with the button when it's submitted as form data.

Note that while it's possible to set the button text with innerHTML, using textContext should be preferred because it's more performant and it can prevent cross-site scripting attacks as its value is not parsed as HTML.

JS:

var b = document.createElement('button');
b.setAttribute('content', 'test content');
b.setAttribute('class', 'btn');  
b.textContent = 'test value';

var wrapper = document.getElementById("divWrapper");
wrapper.appendChild(b);

Produces this in the DOM:

<div id="divWrapper">
    <button content="test content" class="btn">test value</button>
</div>

Demo: https://jsfiddle.net/13ucp6ob/

Can a main() method of class be invoked from another class in java

As far as I understand, the question is NOT about recursion. We can easily call main method of another class in your class. Following example illustrates static and calling by object. Note omission of word static in Class2

class Class1{
    public static void main(String[] args) {
        System.out.println("this is class 1");
    }    
}

class Class2{
    public void main(String[] args) {
        System.out.println("this is class 2");
    }    
}

class MyInvokerClass{
    public static void main(String[] args) {

        System.out.println("this is MyInvokerClass");
        Class2 myClass2 = new Class2();
        Class1.main(args);
        myClass2.main(args);
    }    
}

Output Should be:

this is wrapper class

this is class 1

this is class 2

How do I specify the JDK for a GlassFish domain?

Adding the actual content from dbf's link in order to keep the solution within stackoverflow.

It turns out that when I first installed Glassfish on my Windows system I had JDK 6 installed, and recently I had to downgrade to JDK 5 to compile some code for another project.

Apparently when Glassfish is installed it hard-codes its reference to your JDK location, so to fix this problem I ended up having to edit a file named asenv.bat. In short, I edited this file:

C:\glassfish\config\asenv.bat:

and I commented out the reference to JDK 6 and added a new reference to JDK 5, like this:

REM set AS_JAVA=C:\Program Files\Java\jdk1.6.0_04\jre/..
set AS_JAVA=C:\Program Files\Java\jdk1.5.0_16

Although the path doesn't appear to be case sensitive, I've spent hours debugging an issue around JMS Destination object not found due to my replacement path's case being incorrect.

Does Android support near real time push notification?

Why dont you go with the XMPP implementation. right now there are so many public servers available including gtalk, jabber, citadel etc. For Android there is one SDK is also available named as SMACK. This we cant say a push notification but using the XMPP you can keep a connection open between client and server which will allow a two way communication. Means Android client and server both can communicate to each other. At present this will fulfill the need of Push in android. I have implemented a sample code and it really works great

When a 'blur' event occurs, how can I find out which element focus went *to*?

Can you reverse what you're checking and when? That is if you remeber what was blurred last:

<input id="myInput" onblur="lastBlurred=this;"></input>

and then in the onClick for your span, call function() with both objects:

<span id="mySpan" onClick="function(lastBlurred, this);">Hello World</span>

Your function could then decide whether or not to trigger the Ajax.AutoCompleter control. The function has the clicked object and the blurred object. The onBlur has already happened so it won't make the suggestions disappear.

How to find memory leak in a C++ code/project?

Neither "new" or "delete" should ever be used in application code. Instead, create a new type that uses the manager/worker idiom, in which the manager class allocates and frees memory and forwards all other operations to the worker object.

Unfortunately this is more work than it should be because C++ doesn't have overloading of "operator .". It is even more work in the presence of polymorphism.

But this is worth the effort because you then don't ever have to worry about memory leaks, which means you don't even have to look for them.

What is the best way to insert source code examples into a Microsoft Word document?

Use this - http://hilite.me/

hilite.me converts your code snippets into pretty-printed HTML format, easily embeddable into blog posts, emails and websites.

How: Just copy the source code to the left pane, select the language and the color scheme, and click "Highlight!". The HTML from the right pane can now be pasted to your blog or email, no external CSS or Javascript files are required.

For Microsoft Word document: Copy the the content from the Preview section and paste to your Microsoft Word document.

3 sections : Source Code , HTML and Preview

ActiveSheet.UsedRange.Columns.Count - 8 what does it mean?

UsedRange represents not only nonempty cells, but also formatted cells without any value. And that's why you should be very vigilant.

What's the name for hyphen-separated case?

I've always known it as kebab-case.

On a funny note, I've heard people call it a SCREAM-KEBAB when all the letters are capitalized.

Kebab Case Warning

I've always liked kebab-case as it seems the most readable when you need whitespace. However, some programs interpret the dash as a minus sign, and it can cause problems as what you think is a name turns into a subtraction operation.

first-second  // first minus second?
ten-2 // ten minus two?

Also, some frameworks parse dashes in kebab cased property. For example, GitHub Pages uses Jekyll, and Jekyll parses any dashes it finds in an md file. For example, a file named 2020-1-2-homepage.md on GitHub Pages gets put into a folder structured as \2020\1\2\homepage.html when the site is compiled.

Snake_case vs kebab-case

A safer alternative to kebab-case is snake_case, or SCREAMING_SNAKE_CASE, as underscores cause less confusion when compared to a minus sign.

How to detect control+click in Javascript from an onclick div attribute?

pure javascript:

var ctrlKeyCode = 17;
var cntrlIsPressed = false;

document.addEventListener('keydown', function(event){
    if(event.which=="17")
        cntrlIsPressed = true;
});

document.addEventListener('keyup', function(){
    if(event.which=="17")
        cntrlIsPressed = true;
});



function selectMe(mouseButton)
{
    if(cntrlIsPressed)
    {
        switch(mouseButton)
        {
            case 1:
                alert("Cntrl +  left click");
                break;
            case 2:
                alert("Cntrl + right click");
                break;
            default:
                break;
        }
    }
}

Class JavaLaunchHelper is implemented in two places

This was an issue for me years ago and I'd previously fixed it in Eclipse by excluding 1.7 from my projects, but it became an issue again for IntelliJ, which I recently installed. I fixed it by:

  1. Uninstalling the JDK:

    cd /Library/Java/JavaVirtualMachines
    sudo rm -rf jdk1.8.0_45.jdk
    

    (I had jdk1.8.0_45.jdk installed; obviously you should uninstall whichever java version is listed in that folder. The offending files are located in that folder and should be deleted.)

  2. Downloading and installing JDK 9.

Note that the next time you create a new project, or open an existing project, you will need to set the project SDK to point to the new JDK install. You also may still see this bug or have it creep back if you have JDK 1.7 installed in your JavaVirtualMachines folder (which is what I believe happened to me).

Python + Django page redirect

This should work in most versions of django, I am using it in 1.6.5:

from django.core.urlresolvers import reverse
from django.http import HttpResponseRedirect
urlpatterns = patterns('',
    ....
    url(r'^(?P<location_id>\d+)/$', lambda x, location_id: HttpResponseRedirect(reverse('dailyreport_location', args=[location_id])), name='location_stats_redirect'),
    ....
)

You can still use the name of the url pattern instead of a hard coded url with this solution. The location_id parameter from the url is passed down to the lambda function.

Initialising mock objects - MockIto

A little example for JUnit 5 Jupiter, the "RunWith" was removed you now need to use the Extensions using the "@ExtendWith" Annotation.

@ExtendWith(MockitoExtension.class)
class FooTest {

  @InjectMocks
  ClassUnderTest test = new ClassUnderTest();

  @Spy
  SomeInject bla = new SomeInject();
}

Why does Oracle not find oci.dll?

I was using SQLTool where I was getting oci.dll was not found then I downloaded instantclient-basic-nt-12.2.0.1.0 extracted it and added the folder till oci.dll file in path variable

eg.: Path: .;D:\Softwares\Oracle Instant Client\instantclient_12_2

It resolve my issue, now I am able to open the SQLTool

Backbone.js fetch with parameters

Another example if you are using Titanium Alloy:

 collection.fetch({ 
     data: {
             where : JSON.stringify({
                page: 1
             })
           } 
      });

How to have image and text side by side

HTML

<div class='containerBox'>
    <div>
       <img src='http://ecx.images-amazon.com/images/I/21-leKb-zsL._SL500_AA300_.png' class='iconDetails'>
       <div>
       <h4>Facebook</h4>  
       <div style="font-size:.6em;float:left; margin-left:5px;color:white;">fine location, GPS, coarse location</div>
       <div style="float:right;font-size:.6em; margin-right:5px; color:white;">0 mins ago</div>
       </div>
   </div> 
</div>

CSS

 .iconDetails {
 margin-left:2%;
 float:left; 
 height:40px;
 width:40px;
 } 

.containerBox {
width:300px;
height:60px;
padding:1px;
background-color:#303030;
}
h4{
margin:0px;
margin-top:3%;
margin-left:50px;
color:white;
}

Spring MVC: Complex object as GET @RequestParam

I have a very similar problem. Actually the problem is deeper as I thought. I am using jquery $.post which uses Content-Type:application/x-www-form-urlencoded; charset=UTF-8 as default. Unfortunately I based my system on that and when I needed a complex object as a @RequestParam I couldn't just make it happen.

In my case I am trying to send user preferences with something like;

 $.post("/updatePreferences",  
    {id: 'pr', preferences: p}, 
    function (response) {
 ...

On client side the actual raw data sent to the server is;

...
id=pr&preferences%5BuserId%5D=1005012365&preferences%5Baudio%5D=false&preferences%5Btooltip%5D=true&preferences%5Blanguage%5D=en
...

parsed as;

id:pr
preferences[userId]:1005012365
preferences[audio]:false
preferences[tooltip]:true
preferences[language]:en

and the server side is;

@RequestMapping(value = "/updatePreferences")
public
@ResponseBody
Object updatePreferences(@RequestParam("id") String id, @RequestParam("preferences") UserPreferences preferences) {

    ...
        return someService.call(preferences);
    ...
}

I tried @ModelAttribute, added setter/getters, constructors with all possibilities to UserPreferences but no chance as it recognized the sent data as 5 parameters but in fact the mapped method has only 2 parameters. I also tried Biju's solution however what happens is that, spring creates an UserPreferences object with default constructor and doesn't fill in the data.

I solved the problem by sending JSon string of the preferences from the client side and handle it as if it is a String on the server side;

client:

 $.post("/updatePreferences",  
    {id: 'pr', preferences: JSON.stringify(p)}, 
    function (response) {
 ...

server:

@RequestMapping(value = "/updatePreferences")
public
@ResponseBody
Object updatePreferences(@RequestParam("id") String id, @RequestParam("preferences") String preferencesJSon) {


        String ret = null;
        ObjectMapper mapper = new ObjectMapper();
        try {
            UserPreferences userPreferences = mapper.readValue(preferencesJSon, UserPreferences.class);
            return someService.call(userPreferences);
        } catch (IOException e) {
            e.printStackTrace();
        }
}

to brief, I did the conversion manually inside the REST method. In my opinion the reason why spring doesn't recognize the sent data is the content-type.