Programs & Examples On #Last.fm

Last.fm is a music recommendation service.

How to configure Docker port mapping to use Nginx as an upstream proxy?

Using docker links, you can link the upstream container to the nginx container. An added feature is that docker manages the host file, which means you'll be able to refer to the linked container using a name rather than the potentially random ip.

Doctrine2: Best way to handle many-to-many with extra columns in reference table

I think I would go with @beberlei's suggestion of using proxy methods. What you can do to make this process simpler is to define two interfaces:

interface AlbumInterface {
    public function getAlbumTitle();
    public function getTracklist();
}

interface TrackInterface {
    public function getTrackTitle();
    public function getTrackDuration();
}

Then, both your Album and your Track can implement them, while the AlbumTrackReference can still implement both, as following:

class Album implements AlbumInterface {
    // implementation
}

class Track implements TrackInterface {
    // implementation
}

/** @Entity whatever */
class AlbumTrackReference implements AlbumInterface, TrackInterface
{
    public function getTrackTitle()
    {
        return $this->track->getTrackTitle();
    }

    public function getTrackDuration()
    {
        return $this->track->getTrackDuration();
    }

    public function getAlbumTitle()
    {
        return $this->album->getAlbumTitle();
    }

    public function getTrackList()
    {
        return $this->album->getTrackList();
    }
}

This way, by removing your logic that is directly referencing a Track or an Album, and just replacing it so that it uses a TrackInterface or AlbumInterface, you get to use your AlbumTrackReference in any possible case. What you will need is to differentiate the methods between the interfaces a bit.

This won't differentiate the DQL nor the Repository logic, but your services will just ignore the fact that you're passing an Album or an AlbumTrackReference, or a Track or an AlbumTrackReference because you've hidden everything behind an interface :)

Hope this helps!

Insert json file into mongodb

Below command worked for me

mongoimport --db test --collection docs --file example2.json

when i removed the extra newline character before Email attribute in each of the documents.

example2.json

{"FirstName": "Bruce", "LastName": "Wayne", "Email": "[email protected]"}
{"FirstName": "Lucius", "LastName": "Fox", "Email": "[email protected]"}
{"FirstName": "Dick", "LastName": "Grayson", "Email": "[email protected]"}

Custom "confirm" dialog in JavaScript?

SweetAlert

You should take a look at SweetAlert as an option to save some work. It's beautiful from the default state and is highly customizable.

Confirm Example

sweetAlert(
  {
    title: "Are you sure?",
    text: "You will not be able to recover this imaginary file!",
    type: "warning",   
    showCancelButton: true,   
    confirmButtonColor: "#DD6B55",
    confirmButtonText: "Yes, delete it!"
  }, 
  deleteIt()
);

Sample Alert

Using "label for" on radio buttons

(Firstly read the other answers which has explained the for in the <label></label> tags. Well, both the tops answers are correct, but for my challenge, it was when you have several radio boxes, you should select for them a common name like name="r1" but with different ids id="r1_1" ... id="r1_2"

So this way the answer is more clear and removes the conflicts between name and ids as well.

You need different ids for different options of the radio box.

_x000D_
_x000D_
<input type="radio" name="r1" id="r1_1" />_x000D_
_x000D_
       <label for="r1_1">button text one</label>_x000D_
       <br/>_x000D_
       <input type="radio" name="r1" id="r1_2" />_x000D_
_x000D_
       <label for="r1_2">button text two</label>_x000D_
       <br/>_x000D_
       <input type="radio" name="r1" id="r1_3" />_x000D_
_x000D_
       <label for="r1_3">button text three</label>
_x000D_
_x000D_
_x000D_

Serializing an object as UTF-8 XML in .NET

I found this blog post which explains the problem very well, and defines a few different solutions:

(dead link removed)

I've settled for the idea that the best way to do it is to completely omit the XML declaration when in memory. It actually is UTF-16 at that point anyway, but the XML declaration doesn't seem meaningful until it has been written to a file with a particular encoding; and even then the declaration is not required. It doesn't seem to break deserialization, at least.

As @Jon Hanna mentions, this can be done with an XmlWriter created like this:

XmlWriter writer = XmlWriter.Create (output, new XmlWriterSettings() { OmitXmlDeclaration = true });

How do I find the difference between two values without knowing which is larger?

This does not address the original question, but I thought I would expand on the answer zinturs gave. If you would like to determine the appropriately-signed distance between any two numbers, you could use a custom function like this:

import math

def distance(a, b):
    if (a == b):
        return 0
    elif (a < 0) and (b < 0) or (a > 0) and (b > 0):
        if (a < b):
            return (abs(abs(a) - abs(b)))
        else:
            return -(abs(abs(a) - abs(b)))
    else:
        return math.copysign((abs(a) + abs(b)),b)

print(distance(3,-5))  # -8

print(distance(-3,5))  #  8

print(distance(-3,-5)) #  2

print(distance(5,3))   # -2

print(distance(5,5))   #  0

print(distance(-5,3))  #  8

print(distance(5,-3))  # -8

Please share simpler or more pythonic approaches, if you have one.

What is the color code for transparency in CSS?

try using

background-color: none;

that worked for me.

Base 64 encode and decode example code

For API level 26+

String encodedString = Base64.getEncoder().encodeToString(byteArray);

Ref: https://developer.android.com/reference/java/util/Base64.Encoder.html#encodeToString(byte[])

Combining INSERT INTO and WITH/CTE

Yep:

WITH tab (
  bla bla
)

INSERT INTO dbo.prf_BatchItemAdditionalAPartyNos (  BatchID,                                                        AccountNo,
APartyNo,
SourceRowID)    

SELECT * FROM tab

Note that this is for SQL Server, which supports multiple CTEs:

WITH x AS (), y AS () INSERT INTO z (a, b, c) SELECT a, b, c FROM y

Teradata allows only one CTE and the syntax is as your example.

Javascript - User input through HTML input tag to set a Javascript variable?

I tried to send/add input tag's values into JavaScript variable which worked well for me, here is the code:

<!DOCTYPE html>
<html>
    <head>
        <script type="text/javascript">
            function changef()
            {
            var ctext=document.getElementById("c").value;

            document.writeln(ctext);
            }

        </script>
    </head>
    <body>
        <input type="text" id="c" onchange="changef"();>

        <button type="button" onclick="changef()">click</button>
    </body> 
</html>

"Instantiating" a List in Java?

List is an interface, not a concrete class.
An interface is just a set of functions that a class can implement; it doesn't make any sense to instantiate an interface.

ArrayList is a concrete class that happens to implement this interface and all of the methods in it.

How to count occurrences of a column value efficiently in SQL?

If you're using Oracle, then a feature called analytics will do the trick. It looks like this:

select id, age, count(*) over (partition by age) from students;

If you aren't using Oracle, then you'll need to join back to the counts:

select a.id, a.age, b.age_count
  from students a
  join (select age, count(*) as age_count
          from students
         group by age) b
    on a.age = b.age

Regular expression to extract URL from an HTML link

Regexes are fundamentally bad at parsing HTML (see Can you provide some examples of why it is hard to parse XML and HTML with a regex? for why). What you need is an HTML parser. See Can you provide an example of parsing HTML with your favorite parser? for examples using a variety of parsers.

In particular you will want to look at the Python answers: BeautifulSoup, HTMLParser, and lxml.

CSS center display inline block?

I just changed 2 parameters:

.wrap {
    display: block;
    width:661px;
}

Live Demo

How to get column values in one comma separated value

You tagged the question with both sql-server and plsql so I will provide answers for both SQL Server and Oracle.

In SQL Server you can use FOR XML PATH to concatenate multiple rows together:

select distinct t.[user],
  STUFF((SELECT distinct ', ' + t1.department
         from yourtable t1
         where t.[user] = t1.[user]
            FOR XML PATH(''), TYPE
            ).value('.', 'NVARCHAR(MAX)') 
        ,1,2,'') department
from yourtable t;

See SQL Fiddle with Demo.

In Oracle 11g+ you can use LISTAGG:

select "User",
  listagg(department, ',') within group (order by "User") as departments
from yourtable
group by "User"

See SQL Fiddle with Demo

Prior to Oracle 11g, you could use the wm_concat function:

select "User",
  wm_concat(department) departments
from yourtable
group by "User"

How does BitLocker affect performance?

Some practical tests...

  • Dell Latitude E7440
  • Intel Core i7-4600U
  • 16.0 GB
  • Windows 8.1 Professional
  • LiteOn IT LMT-256M6M MSATA 256GB

This test is using a system partition. Results for a non-system partition are a bit better.

Score decrease:
Read: 5%
Write: 16%

Without BitLocker:

Without BitLocker

With BitLocker:

With BitLocker

So you can see that with a very strong configuration and a modern SSD disk you can see a small performance degradation with tests. I don't know what about a typical work, especially with the Visual Studio.

SVN checkout the contents of a folder, not the folder itself

Just add the directory on the command line:

svn checkout svn://192.168.1.1/projectname/ target-directory/

How to check for null/empty/whitespace values with a single test?

Use below query and it works

SELECT column_name FROM table_name where isnull(column_name,'') <> ''

How to validate an Email in PHP?

Stay away from regex and filter_var() solutions for validating email. See this answer: https://stackoverflow.com/a/42037557/953833

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

Yes as long as it is public and you pass the correct args. See this link for more information. http://www.codestyle.org/java/faq-CommandLine.shtml#mainhost

TypeError: 'module' object is not callable

When configuring an console_scripts entrypoint in setup.py I found this issue existed when the endpoint was a module or package rather than a function within the module.

Traceback (most recent call last):
   File "/Users/ubuntu/.virtualenvs/virtualenv/bin/mycli", line 11, in <module>
load_entry_point('my-package', 'console_scripts', 'mycli')()
TypeError: 'module' object is not callable

For example

from setuptools import setup
setup (
# ...
    entry_points = {
        'console_scripts': [mycli=package.module.submodule]
    },
# ...
)

Should have been

from setuptools import setup
setup (
# ...
    entry_points = {
        'console_scripts': [mycli=package.module.submodule:main]
    },
# ...
)

So that it would refer to a callable function rather than the module itself. It seems to make no difference if the module has a if __name__ == '__main__': block. This will not make the module callable.

Converting HTML to PDF using PHP?

If you wish to create a pdf from php, pdflib will help you (as some others suggested).

Else, if you want to convert an HTML page to PDF via PHP, you'll find a little trouble outta here.. For 3 years I've been trying to do it as best as I can.

So, the options I know are:

DOMPDF : php class that wraps the html and builds the pdf. Works good, customizable (if you know php), based on pdflib, if I remember right it takes even some CSS. Bad news: slow when the html is big or complex.

HTML2PS: same as DOMPDF, but this one converts first to a .ps (ghostscript) file, then, to whatever format you need (pdf, jpg, png). For me is little better than dompdf, but has the same speed problem.. but, better compatibility with CSS.

Those two are php classes, but if you can install some software on the server, and access it throught passthru() or system(), give a look to these too:

wkhtmltopdf: based on webkit (safari's wrapper), is really fast and powerful.. seems like this is the best one (atm) for converting html pages to pdf on the fly; taking only 2 seconds for a 3 page xHTML document with CSS2. It is a recent project, anyway, the google.code page is often updated.

htmldoc : This one is a tank, it never really stops/crashes.. the project looks dead since 2007, but anyway if you don't need CSS compatibility this can be nice for you.

init-param and context-param

Consider the below definition in web.xml

<servlet>
    <servlet-name>HelloWorld</servlet-name>
    <servlet-class>TestServlet</servlet-class>
    <init-param>
        <param-name>myprop</param-name>
        <param-value>value</param-value>
    </init-param>
</servlet>

You can see that init-param is defined inside a servlet element. This means it is only available to the servlet under declaration and not to other parts of the web application. If you want this parameter to be available to other parts of the application say a JSP this needs to be explicitly passed to the JSP. For instance passed as request.setAttribute(). This is highly inefficient and difficult to code.

So if you want to get access to global values from anywhere within the application without explicitly passing those values, you need to use Context Init parameters.

Consider the following definition in web.xml

 <web-app>
      <context-param>
           <param-name>myprop</param-name>
           <param-value>value</param-value>
      </context-param>
 </web-app>

This context param is available to all parts of the web application and it can be retrieved from the Context object. For instance, getServletContext().getInitParameter(“dbname”);

From a JSP you can access the context parameter using the application implicit object. For example, application.getAttribute(“dbname”);

Java Security: Illegal key size or default parameters?

I also got the issue but after replacing existing one with the downloaded (from JCE) one resolved the issue. New crypto files provided unlimited strength.

How do I change file permissions in Ubuntu

If you just want to change file permissions, you want to be careful about using -R on chmod since it will change anything, files or folders. If you are doing a relative change (like adding write permission for everyone), you can do this:

sudo chmod -R a+w /var/www

But if you want to use the literal permissions of read/write, you may want to select files versus folders:

sudo find /var/www -type f -exec chmod 666 {} \;

(Which, by the way, for security reasons, I wouldn't recommend either of these.)

Or for folders:

sudo find /var/www -type d -exec chmod 755 {} \;

INSTALL_FAILED_MISSING_SHARED_LIBRARY error in Android

When I try these solutions.
I solved with:
create a new virtual device( select Google APIs(Google Inc)-API Level 15 replace android 4.0.3-APILevel 15 ) then run again. It solved.

I think it's just because the device have no google apis~

IDE:android-studio OS:ubuntu 12.04

Add 10 seconds to a Date

There's a setSeconds method as well:

var t = new Date();
t.setSeconds(t.getSeconds() + 10);

For a list of the other Date functions, you should check out MDN


setSeconds will correctly handle wrap-around cases:

_x000D_
_x000D_
var d;_x000D_
d = new Date('2014-01-01 10:11:55');_x000D_
alert(d.getMinutes() + ':' + d.getSeconds()); //11:55_x000D_
d.setSeconds(d.getSeconds() + 10);_x000D_
alert(d.getMinutes() + ':0' + d.getSeconds()); //12:05
_x000D_
_x000D_
_x000D_

How do I remove the passphrase for the SSH key without having to create a new key?

You might want to add the following to your .bash_profile (or equivalent), which starts ssh-agent on login.

if [ -f ~/.agent.env ] ; then
    . ~/.agent.env > /dev/null
    if ! kill -0 $SSH_AGENT_PID > /dev/null 2>&1; then
        echo "Stale agent file found. Spawning new agent… "
        eval `ssh-agent | tee ~/.agent.env`
        ssh-add
    fi 
else
    echo "Starting ssh-agent"
    eval `ssh-agent | tee ~/.agent.env`
    ssh-add
fi

On some Linux distros (Ubuntu, Debian) you can use:

ssh-copy-id -i ~/.ssh/id_dsa.pub username@host

This will copy the generated id to a remote machine and add it to the remote keychain.

You can read more here and here.

How do I compare two strings in Perl?

print "Matched!\n" if ($str1 eq $str2)

Perl has seperate string comparison and numeric comparison operators to help with the loose typing in the language. You should read perlop for all the different operators.

How to highlight text using javascript

I have the same problem, a bunch of text comes in through a xmlhttp request. This text is html formatted. I need to highlight every occurrence.

str='<img src="brown fox.jpg" title="The brown fox" />'
    +'<p>some text containing fox.</p>'

The problem is that I don't need to highlight text in tags. For example I need to highlight fox:

Now I can replace it with:

var word="fox";
word="(\\b"+ 
    word.replace(/([{}()[\]\\.?*+^$|=!:~-])/g, "\\$1")
        + "\\b)";
var r = new RegExp(word,"igm");
str.replace(r,"<span class='hl'>$1</span>")

To answer your question: you can leave out the g in regexp options and only first occurrence will be replaced but this is still the one in the img src property and destroys the image tag:

<img src="brown <span class='hl'>fox</span>.jpg" title="The brown <span 
class='hl'>fox</span> />

This is the way I solved it but was wondering if there is a better way, something I've missed in regular expressions:

str='<img src="brown fox.jpg" title="The brown fox" />'
    +'<p>some text containing fox.</p>'
var word="fox";
word="(\\b"+ 
    word.replace(/([{}()[\]\\.?*+^$|=!:~-])/g, "\\$1")
    + "\\b)";
var r = new RegExp(word,"igm");
str.replace(/(>[^<]+<)/igm,function(a){
    return a.replace(r,"<span class='hl'>$1</span>");
});

Read a variable in bash with a default value

You can use parameter expansion, e.g.

read -p "Enter your name [Richard]: " name
name=${name:-Richard}
echo $name

Including the default value in the prompt between brackets is a fairly common convention

What does the :-Richard part do? From the bash manual:

${parameter:-word} If parameter is unset or null, the expansion of word is substituted. Otherwise, the value of parameter is substituted.

Also worth noting that...

In each of the cases below, word is subject to tilde expansion, parameter expansion, command substitution, and arithmetic expansion.

So if you use webpath=${webpath:-~/httpdocs} you will get a result of /home/user/expanded/path/httpdocs not ~/httpdocs, etc.

The remote host closed the connection. The error code is 0x800704CD

I was getting this on an asp.net 2.0 iis7 Windows2008 site. Same code on iis6 worked fine. It was causing an issue for me because it was messing up the login process. User would login and get a 302 to default.asxp, which would get through page_load, but not as far as pre-render before iis7 would send a 302 back to login.aspx without the auth cookie. I started playing with app pool settings, and for some reason 'enable 32 bit applications' seems to have fixed it. No idea why, since this site isn't doing anything special that should require any 32 bit drivers. We have some sites that still use Access that require 32bit, but not our straight SQL sites like this one.

How to get UTF-8 working in Java webapps?

One other point that hasn't been mentioned relates to Java Servlets working with Ajax. I have situations where a web page is picking up utf-8 text from the user sending this to a JavaScript file which includes it in a URI sent to the Servlet. The Servlet queries a database, captures the result and returns it as XML to the JavaScript file which formats it and inserts the formatted response into the original web page.

In one web app I was following an early Ajax book's instructions for wrapping up the JavaScript in constructing the URI. The example in the book used the escape() method, which I discovered (the hard way) is wrong. For utf-8 you must use encodeURIComponent().

Few people seem to roll their own Ajax these days, but I thought I might as well add this.

Understanding Popen.communicate

.communicate() writes input (there is no input in this case so it just closes subprocess' stdin to indicate to the subprocess that there is no more input), reads all output, and waits for the subprocess to exit.

The exception EOFError is raised in the child process by raw_input() (it expected data but got EOF (no data)).

p.stdout.read() hangs forever because it tries to read all output from the child at the same time as the child waits for input (raw_input()) that causes a deadlock.

To avoid the deadlock you need to read/write asynchronously (e.g., by using threads or select) or to know exactly when and how much to read/write, for example:

from subprocess import PIPE, Popen

p = Popen(["python", "-u", "1st.py"], stdin=PIPE, stdout=PIPE, bufsize=1)
print p.stdout.readline(), # read the first line
for i in range(10): # repeat several times to show that it works
    print >>p.stdin, i # write input
    p.stdin.flush() # not necessary in this case
    print p.stdout.readline(), # read output

print p.communicate("n\n")[0], # signal the child to exit,
                               # read the rest of the output, 
                               # wait for the child to exit

Note: it is a very fragile code if read/write are not in sync; it deadlocks.

Beware of block-buffering issue (here it is solved by using "-u" flag that turns off buffering for stdin, stdout in the child).

bufsize=1 makes the pipes line-buffered on the parent side.

How to calculate mean, median, mode and range from a set of numbers

public class Mode {
    public static void main(String[] args) {
        int[] unsortedArr = new int[] { 3, 1, 5, 2, 4, 1, 3, 4, 3, 2, 1, 3, 4, 1 ,-1,-1,-1,-1,-1};
        Map<Integer, Integer> countMap = new HashMap<Integer, Integer>();

        for (int i = 0; i < unsortedArr.length; i++) {
            Integer value = countMap.get(unsortedArr[i]);

            if (value == null) {
                countMap.put(unsortedArr[i], 0);
            } else {
                int intval = value.intValue();
                intval++;
                countMap.put(unsortedArr[i], intval);
            }
        }

        System.out.println(countMap.toString());

        int max = getMaxFreq(countMap.values());
        List<Integer> modes = new ArrayList<Integer>();

        for (Entry<Integer, Integer> entry : countMap.entrySet()) {
            int value = entry.getValue();
            if (value == max)
                modes.add(entry.getKey());
        }
        System.out.println(modes);
    }

    public static int getMaxFreq(Collection<Integer> valueSet) {
        int max = 0;
        boolean setFirstTime = false;

        for (Iterator iterator = valueSet.iterator(); iterator.hasNext();) {
            Integer integer = (Integer) iterator.next();

            if (!setFirstTime) {
                max = integer;
                setFirstTime = true;
            }
            if (max < integer) {
                max = integer;
            }
        }
        return max;
    }
}

Test data

Modes {1,3} for { 3, 1, 5, 2, 4, 1, 3, 4, 3, 2, 1, 3, 4, 1 };
Modes {-1} for { 3, 1, 5, 2, 4, 1, 3, 4, 3, 2, 1, 3, 4, 1 ,-1,-1,-1,-1,-1};

unary operator expected in shell script when comparing null value with string

Why all people want to use '==' instead of simple '=' ? It is bad habit! It used only in [[ ]] expression. And in (( )) too. But you may use just = too! It work well in any case. If you use numbers, not strings use not parcing to strings and then compare like strings but compare numbers. like that

let -i i=5 # garantee that i is nubmber
test $i -eq 5 && echo "$i is equal 5" || echo "$i not equal 5"

It's match better and quicker. I'm expert in C/C++, Java, JavaScript. But if I use bash i never use '==' instead '='. Why you do so?

Java - creating a new thread

Please try this. You will understand all perfectly after you will take a look on my solution.

There are only 2 ways of creating threads in java

with implements Runnable

class One implements Runnable {
@Override
public void run() {
    System.out.println("Running thread 1 ... ");
}

with extends Thread

class Two extends Thread {
@Override
public void run() {
    System.out.println("Running thread 2 ... ");
}

Your MAIN class here

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

    One demo1 = new One();
    Thread t1 = new Thread(demo1);
    t1.start();

    Two demo2 = new Two();
    Thread t2 = new Thread(demo2);
    t2.start();
}

}

How do I run a program with commandline arguments using GDB within a Bash script?

gdb has --init-command <somefile> where somefile has a list of gdb commands to run, I use this to have //GDB comments in my code, then `

echo "file ./a.out" > run
grep -nrIH "//GDB"|
    sed "s/\(^[^:]\+:[^:]\+\):.*$/\1/g" |
    awk '{print "b" " " $1}'|
    grep -v $(echo $0|sed "s/.*\///g") >> run
gdb --init-command ./run -ex=r

as a script, which puts the command to load the debug symbols, and then generates a list of break commands to put a break point for each //GDB comment, and starts it running

What is "origin" in Git?

The other answers say that origin is an alias for the URL of a remote repository which is not entirely accurate. It should be noted that an address that starts with http is a URL while one that starts with git@ is a URI or Universal Resource Identifier.

All URLs are URIs, but not all URIs are URLs.

In short, when you type git remote add origin <URI> you are telling your local git that whenever you use the word origin you actually mean the URI that you specified. Think of it like a variable holding a value.

And just like a variable, you can name it whatever you want (eg. github, heroku, destination, etc).

How do you get the contextPath from JavaScript, the right way?

Got it :D

function getContextPath() {
   return window.location.pathname.substring(0, window.location.pathname.indexOf("/",2));
}
alert(getContextPath());

Important note: Does only work for the "root" context path. Does not work with "subfolders", or if context path has a slash ("/") in it.

How to overwrite files with Copy-Item in PowerShell

How about calling the .NET Framework methods?

You can do ANYTHING with them... :

[System.IO.File]::Copy($src, $dest, $true);

The $true argument makes it overwrite.

Insert current date/time using now() in a field using MySQL/PHP

These both work fine for me...

<?php
  $db = mysql_connect('localhost','user','pass');
  mysql_select_db('test_db');

  $stmt = "INSERT INTO `test` (`first`,`last`,`whenadded`) VALUES ".
          "('{$first}','{$last}','NOW())";
  $rslt = mysql_query($stmt);

  $stmt = "INSERT INTO `users` (`first`,`last`,`whenadded`) VALUES ".
          "('{$first}', '{$last}', CURRENT_TIMESTAMP)";
  $rslt = mysql_query($stmt);

?>

Side note: mysql_query() is not the best way to connect to MySQL in current versions of PHP.

phpmailer: Reply using only "Reply To" address

At least in the current versions of PHPMailers, there's a function clearReplyTos() to empty the reply-to array.

    $mail->ClearReplyTos();
    $mail->addReplyTo([email protected], 'EXAMPLE');

Getting ORA-01031: insufficient privileges while querying a table instead of ORA-00942: table or view does not exist

In SQL Developer: Everything was working fine and I had all the permissions to login and there was no password change and I could click the table and see the data tab.

But when I run query (simple select statement) it was showing "ORA-01031: insufficient privileges" message.

The solution is simply disconnect the connection and reconnect. Note: only doing Reconnect did not work for me. SQL Developer Disconnect Snapshot

How can I make setInterval also work when a tab is inactive in Chrome?

On most browsers inactive tabs have low priority execution and this can affect JavaScript timers.

If the values of your transition were calculated using real time elapsed between frames instead fixed increments on each interval, you not only workaround this issue but also can achieve a smother animation by using requestAnimationFrame as it can get up to 60fps if the processor isn't very busy.

Here's a vanilla JavaScript example of an animated property transition using requestAnimationFrame:

_x000D_
_x000D_
var target = document.querySelector('div#target')_x000D_
var startedAt, duration = 3000_x000D_
var domain = [-100, window.innerWidth]_x000D_
var range = domain[1] - domain[0]_x000D_
_x000D_
function start() {_x000D_
  startedAt = Date.now()_x000D_
  updateTarget(0)_x000D_
  requestAnimationFrame(update)_x000D_
}_x000D_
_x000D_
function update() {_x000D_
  let elapsedTime = Date.now() - startedAt_x000D_
_x000D_
  // playback is a value between 0 and 1_x000D_
  // being 0 the start of the animation and 1 its end_x000D_
  let playback = elapsedTime / duration_x000D_
_x000D_
  updateTarget(playback)_x000D_
  _x000D_
  if (playback > 0 && playback < 1) {_x000D_
   // Queue the next frame_x000D_
   requestAnimationFrame(update)_x000D_
  } else {_x000D_
   // Wait for a while and restart the animation_x000D_
   setTimeout(start, duration/10)_x000D_
  }_x000D_
}_x000D_
_x000D_
function updateTarget(playback) {_x000D_
  // Uncomment the line below to reverse the animation_x000D_
  // playback = 1 - playback_x000D_
_x000D_
  // Update the target properties based on the playback position_x000D_
  let position = domain[0] + (playback * range)_x000D_
  target.style.left = position + 'px'_x000D_
  target.style.top = position + 'px'_x000D_
  target.style.transform = 'scale(' + playback * 3 + ')'_x000D_
}_x000D_
_x000D_
start()
_x000D_
body {_x000D_
  overflow: hidden;_x000D_
}_x000D_
_x000D_
div {_x000D_
    position: absolute;_x000D_
    white-space: nowrap;_x000D_
}
_x000D_
<div id="target">...HERE WE GO</div>
_x000D_
_x000D_
_x000D_


For Background Tasks (non-UI related)

@UpTheCreek comment:

Fine for presentation issues, but still there are some things that you need to keep running.

If you have background tasks that needs to be precisely executed at given intervals, you can use HTML5 Web Workers. Take a look at Möhre's answer below for more details...

CSS vs JS "animations"

This problem and many others could be avoided by using CSS transitions/animations instead of JavaScript based animations which adds a considerable overhead. I'd recommend this jQuery plugin that let's you take benefit from CSS transitions just like the animate() methods.

Matplotlib figure facecolor (background color)

If you want to change background color, try this:

plt.rcParams['figure.facecolor'] = 'white'

jQuery - trapping tab select event

In later versions of JQuery they have changed the function from select to activate. http://api.jqueryui.com/tabs/#event-activate

Get month name from Date

To get a array of month name :

Date.monthNames = function( ) {
var arrMonth = [],
    dateRef = new Date(),
    year = dateRef.getFullYear();

dateRef.setMonth(0);
while (year == dateRef.getFullYear()) {
    /* push le mois en lettre et passe au mois suivant */
    arrMonth.push( (dateRef.toLocaleString().split(' '))[2] );
    dateRef.setMonth( dateRef.getMonth() + 1);
}

return arrMonth;
}

alert(Date.monthNames().toString());

// -> janvier,février,mars,avril,mai,juin,juillet,août,septembre,octobre,novembre,décembre

http://jsfiddle.net/polinux/qb346/

vue.js 'document.getElementById' shorthand

You can use the directive v-el to save an element and then use it later.

https://vuejs.org/api/#vm-els

<div v-el:my-div></div>
<!-- this.$els.myDiv --->

Edit: This is deprecated in Vue 2, see ??? answer

Setting focus to iframe contents

I discovered that FF triggers the focus event for iframe.contentWindow but not for iframe.contentWindow.document. Chrome for example can handle both cases. so, I just needed to bind my event handlers to iframe.contentWindow in order to get things working. Maybe this helps somebody ...

Adding files to a GitHub repository

Open github app. Then, add the Folder of files into the github repo file onto your computer (You WILL need to copy the repo onto your computer. Most repo files are located in the following directory: C:\Users\USERNAME\Documents\GitHub\REPONAME) Then, in the github app, check our your repo. You can easily commit from there.

How to add pandas data to an existing csv file?

Initially starting with a pyspark dataframes - I got type conversion errors (when converting to pandas df's and then appending to csv) given the schema/column types in my pyspark dataframes

Solved the problem by forcing all columns in each df to be of type string and then appending this to csv as follows:

with open('testAppend.csv', 'a') as f:
    df2.toPandas().astype(str).to_csv(f, header=False)

How do you develop Java Servlets using Eclipse?

I use Eclipse Java EE edition

Create a "Dynamic Web Project"

Install a local server in the server view, for the version of Tomcat I'm using. Then debug, and run on that server for testing.

When I deploy I export the project to a war file.

A CSS selector to get last visible div

Pure JS solution (eg. when you don't use jQuery or another framework to other things and don't want to download that just for this task):

<div>A</div>
<div>B</div>  
<div>C</div>  
<div style="display:none">D</div>
<div style="display:none">E</div>    

<script>
var divs = document.getElementsByTagName('div');
var last;

if (divs) {
    for (var i = 0; i < divs.length; i++) {
        if (divs[i].style.display != 'none') {
            last = divs[i];           
        }
    }
}

if (last) {
    last.style.background = 'red';
}
</script>

http://jsfiddle.net/uEeaA/90/

Math functions in AngularJS bindings

While the accepted answer is right that you can inject Math to use it in angular, for this particular problem, the more conventional/angular way is the number filter:

<p>The percentage is {{(100*count/total)| number:0}}%</p>

You can read more about the number filter here: http://docs.angularjs.org/api/ng/filter/number

How to avoid annoying error "declared and not used"

One angle not so far mentioned is tool sets used for editing the code.

Using Visual Studio Code along with the Extension from lukehoban called Go will do some auto-magic for you. The Go extension automatically runs gofmt, golint etc, and removes and adds import entries. So at least that part is now automatic.

I will admit its not 100% of the solution to the question, but however useful enough.

What does this square bracket and parenthesis bracket notation mean [first1,last1)?

The concept of interval notation comes up in both Mathematics and Computer Science. The Mathematical notation [, ], (, ) denotes the domain (or range) of an interval.

  • The brackets [ and ] means:

    1. The number is included,
    2. This side of the interval is closed,
  • The parenthesis ( and ) means:

    1. The number is excluded,
    2. This side of the interval is open.

An interval with mixed states is called "half-open".

For example, the range of consecutive integers from 1 .. 10 (inclusive) would be notated as such:

  • [1,10]

Notice how the word inclusive was used. If we want to exclude the end point but "cover" the same range we need to move the end-point:

  • [1,11)

For both left and right edges of the interval there are actually 4 permutations:

(1,10) =   2,3,4,5,6,7,8,9       Set has  8 elements
(1,10] =   2,3,4,5,6,7,8,9,10    Set has  9 elements
[1,10) = 1,2,3,4,5,6,7,8,9       Set has  9 elements
[1,10] = 1,2,3,4,5,6,7,8,9,10    Set has 10 elements

How does this relate to Mathematics and Computer Science?

Array indexes tend to use a different offset depending on which field are you in:

  • Mathematics tends to be one-based.
  • Certain programming languages tends to be zero-based, such as C, C++, Javascript, Python, while other languages such as Mathematica, Fortran, Pascal are one-based.

These differences can lead to subtle fence post errors, aka, off-by-one bugs when implementing Mathematical algorithms such as for-loops.

Integers

If we have a set or array, say of the first few primes [ 2, 3, 5, 7, 11, 13, 17, 19, 23, 29 ], Mathematicians would refer to the first element as the 1st absolute element. i.e. Using subscript notation to denote the index:

  • a1 = 2
  • a2 = 3
  • :
  • a10 = 29

Some programming languages, in contradistinction, would refer to the first element as the zero'th relative element.

  • a[0] = 2
  • a[1] = 3
  • :
  • a[9] = 29

Since the array indexes are in the range [0,N-1] then for clarity purposes it would be "nice" to keep the same numerical value for the range 0 .. N instead of adding textual noise such as a -1 bias.

For example, in C or JavaScript, to iterate over an array of N elements a programmer would write the common idiom of i = 0, i < N with the interval [0,N) instead of the slightly more verbose [0,N-1]:

_x000D_
_x000D_
function main() {_x000D_
    var output = "";_x000D_
    var a = [ 2, 3, 5, 7,  11, 13, 17, 19, 23, 29 ];_x000D_
    for( var i = 0; i < 10; i++ ) // [0,10)_x000D_
       output += "[" + i + "]: " + a[i] + "\n";_x000D_
_x000D_
    if (typeof window === 'undefined') // Node command line_x000D_
        console.log( output )_x000D_
    else_x000D_
        document.getElementById('output1').innerHTML = output;_x000D_
}
_x000D_
 <html>_x000D_
     <body onload="main();">_x000D_
         <pre id="output1"></pre>_x000D_
     </body>_x000D_
 </html>
_x000D_
_x000D_
_x000D_

Mathematicians, since they start counting at 1, would instead use the i = 1, i <= N nomenclature but now we need to correct the array offset in a zero-based language.

e.g.

_x000D_
_x000D_
function main() {_x000D_
    var output = "";_x000D_
    var a = [ 2, 3, 5, 7,  11, 13, 17, 19, 23, 29 ];_x000D_
    for( var i = 1; i <= 10; i++ ) // [1,10]_x000D_
       output += "[" + i + "]: " + a[i-1] + "\n";_x000D_
_x000D_
    if (typeof window === 'undefined') // Node command line_x000D_
        console.log( output )_x000D_
    else_x000D_
        document.getElementById( "output2" ).innerHTML = output;_x000D_
}
_x000D_
<html>_x000D_
    <body onload="main()";>_x000D_
        <pre id="output2"></pre>_x000D_
    </body>_x000D_
</html>
_x000D_
_x000D_
_x000D_

Aside:

In programming languages that are 0-based you might need a kludge of a dummy zero'th element to use a Mathematical 1-based algorithm. e.g. Python Index Start

Floating-Point

Interval notation is also important for floating-point numbers to avoid subtle bugs.

When dealing with floating-point numbers especially in Computer Graphics (color conversion, computational geometry, animation easing/blending, etc.) often times normalized numbers are used. That is, numbers between 0.0 and 1.0.

It is important to know the edge cases if the endpoints are inclusive or exclusive:

  • (0,1) = 1e-M .. 0.999...
  • (0,1] = 1e-M .. 1.0
  • [0,1) = 0.0 .. 0.999...
  • [0,1] = 0.0 .. 1.0

Where M is some machine epsilon. This is why you might sometimes see const float EPSILON = 1e-# idiom in C code (such as 1e-6) for a 32-bit floating point number. This SO question Does EPSILON guarantee anything? has some preliminary details. For a more comprehensive answer see FLT_EPSILON and David Goldberg's What Every Computer Scientist Should Know About Floating-Point Arithmetic

Some implementations of a random number generator, random() may produce values in the range 0.0 .. 0.999... instead of the more convenient 0.0 .. 1.0. Proper comments in the code will document this as [0.0,1.0) or [0.0,1.0] so there is no ambiguity as to the usage.

Example:

  • You want to generate random() colors. You convert three floating-point values to unsigned 8-bit values to generate a 24-bit pixel with red, green, and blue channels respectively. Depending on the interval output by random() you may end up with near-white (254,254,254) or white (255,255,255).
     +--------+-----+
     |random()|Byte |
     |--------|-----|
     |0.999...| 254 | <-- error introduced
     |1.0     | 255 |
     +--------+-----+

For more details about floating-point precision and robustness with intervals see Christer Ericson's Real-Time Collision Detection, Chapter 11 Numerical Robustness, Section 11.3 Robust Floating-Point Usage.

NSPhotoLibraryUsageDescription key must be present in Info.plist to use camera roll

You need to paste these two in your info.plist, The only way that worked in iOS 11 for me.

    <key>NSPhotoLibraryUsageDescription</key>
    <string>This app requires access to the photo library.</string>

    <key>NSPhotoLibraryAddUsageDescription</key>
    <string>This app requires access to the photo library.</string>

CSS: Position loading indicator in the center of the screen

Worked for me in angular 4

by adding style="margin:0 auto;"

<mat-progress-spinner
  style="margin:0 auto;"
  *ngIf="isLoading"
  mode="indeterminate">
  </mat-progress-spinner>

What .NET collection provides the fastest search

If you aren't worried about squeaking every single last bit of performance the suggestion to use a HashSet or binary search is solid. Your datasets just aren't large enough that this is going to be a problem 99% of the time.

But if this just one of thousands of times you are going to do this and performance is critical (and proven to be unacceptable using HashSet/binary search), you could certainly write your own algorithm that walked the sorted lists doing comparisons as you went. Each list would be walked at most once and in the pathological cases wouldn't be bad (once you went this route you'd probably find that the comparison, assuming it's a string or other non-integral value, would be the real expense and that optimizing that would be the next step).

How to completely remove a dialog on close

Why do you want to remove it?

If it is to prevent multiple instances being created, then just use the following approach...

$('#myDialog') 
    .dialog( 
    { 
        title: 'Error', 
        close: function(event, ui) 
        { 
            $(this).dialog('close');
        } 
    }); 

And when the error occurs, you would do...

$('#myDialog').html("Ooops.");
$('#myDialog').dialog('open');

Create an empty list in python with certain size

One simple way to create a 2D matrix of size n using nested list comprehensions:

m = [[None for _ in range(n)] for _ in range(n)]

Skip over a value in the range function in python

It depends on what you want to do. For example you could stick in some conditionals like this in your comprehensions:

# get the squares of each number from 1 to 9, excluding 2
myList = [i**2 for i in range(10) if i != 2]
print(myList)

# --> [0, 1, 9, 16, 25, 36, 49, 64, 81]

bootstrap initially collapsed element

You need to remove "in" from "collapse in"

How to set Angular 4 background image?

I wanted a profile picture of size 96x96 with data from api. The following solution worked for me in project Angular 7.

.ts:

  @Input() profile;

.html:

 <span class="avatar" [ngStyle]="{'background-image': 'url('+ profile?.public_picture +')'}"></span>

.scss:

 .avatar {
      border-radius: 100%;
      background-size: cover;
      background-position: center center;
      background-repeat: no-repeat;
      width: 96px;
      height: 96px;
    }

Please note that if you write background instead of 'background-image' in [ngStyle], the styles you write (even in style of element) for other background properties like background-position/size, etc. won't work. Because you will already fix it's properties with background: 'url(+ property +) (no providers for size, position, etc. !)'. The [ngStyle] priority is higher than style of element. In background here, only url() property will work. Be sure to use 'background-image' instead of 'background'in case you want to write more properties to background image.

Setting width as a percentage using jQuery

Using the width function:

$('div#somediv').width('70%');

will turn:

<div id="somediv" />

into:

<div id="somediv" style="width: 70%;"/>

css label width not taking effect

Make it a block first, then float left to stop pushing the next block in to a new line.

#report-upload-form label {
                           padding-left:26px;
                           width:125px;
                           text-transform: uppercase;
                           display:block;
                           float:left
}

Plot multiple boxplot in one graph

Since you don't mention a plot package , I propose here using Lattice version( I think there is more ggplot2 answers than lattice ones, at least since I am here in SO).

 ## reshaping the data( similar to the other answer)
 library(reshape2)
 dat.m <- melt(TestData,id.vars='Label')
 library(lattice)
 bwplot(value~Label |variable,    ## see the powerful conditional formula 
        data=dat.m,
        between=list(y=1),
        main="Bad or Good")

enter image description here

How do I embed a mp4 movie into my html?

If you have an mp4 video residing at your server, and you want the visitors to stream that over your HTML page.

<video width="480" height="320" controls="controls">
<source src="http://serverIP_or_domain/location_of_video.mp4" type="video/mp4">
</video>

How can a query multiply 2 cell for each row MySQL?

this was my solution:

i was looking for how to display the result not to calculate...

so. in this case. there is no column TOTAL in the database, but there is a total on the webpage...

 <td><?php echo $row['amount1'] * $row['amount2'] ?></td>

also this was needed first...

<?php 
   $conn=mysql_connect('localhost','testbla','adminbla');
mysql_select_db("testa",$conn);

$query1 = "select * from info2";
$get=mysql_query($query1);
while($row=mysql_fetch_array($get)){
   ?>

How to display a content in two-column layout in LaTeX?

Load the multicol package, like this \usepackage{multicol}. Then use:

\begin{multicols}{2}
Column 1
\columnbreak
Column 2
\end{multicols}

If you omit the \columnbreak, the columns will balance automatically.

Why does Git tell me "No such remote 'origin'" when I try to push to origin?

Two problems:

1 - You never told Git to start tracking any file

You write that you ran

git init
git commit -m "first commit"

and that, at that stage, you got

nothing added to commit but untracked files present (use "git add" to track).

Git is telling you that you never told it to start tracking any files in the first place, and it has nothing to take a snapshot of. Therefore, Git creates no commit. Before attempting to commit, you should tell Git (for instance):

Hey Git, you see that README.md file idly sitting in my working directory, there? Could you put it under version control for me? I'd like it to go in my first commit/snapshot/revision...

For that you need to stage the files of interest, using

git add README.md

before running

git commit -m "some descriptive message"

2 - You haven't set up the remote repository

You then ran

git remote add origin https://github.com/VijayNew/NewExample.git

After that, your local repository should be able to communicate with the remote repository that resides at the specified URL (https://github.com/VijayNew/NewExample.git)... provided that remote repo actually exists! However, it seems that you never created that remote repo on GitHub in the first place: at the time of writing this answer, if I try to visit the correponding URL, I get

enter image description here

Before attempting to push to that remote repository, you need to make sure that the latter actually exists. So go to GitHub and create the remote repo in question. Then and only then will you be able to successfully push with

git push -u origin master

git returns http error 407 from proxy after CONNECT

I had faced similar issue, behind corporate firewall. Did the following, and able to clone repository using git shell from my system running Windows 7 SP1.

  1. Set 'all_proxy' environment variable for your user. Required by curl.

    export all_proxy=http://DOMAIN\proxyuser:[email protected]:8080
    
  2. Set 'https_proxy' environment variable for your user. Required by curl.

    export https_proxy=http://DOMAIN\proxyuser:[email protected]:8080
    
  3. I am not sure if this has any impact. But I did this and it worked:

    git config --global http.sslverify false
    
  4. Use https:// for cloning

    git clone https://github.com/project/project.git
    

Note-1: Do not use http://. Using that can give the below error. It can be resolved by using https://.

 error: RPC failed; result=56, HTTP code = 301

Note-2: Avoid having @ in your password. Can use $ though.

What is the difference between private and protected members of C++ classes?

Private : Accessible by class member functions & friend function or friend class. For C++ class this is default access specifier.

Protected: Accessible by class member functions, friend function or friend class & derived classes.

  • You can keep class member variable or function (even typedefs or inner classes) as private or protected as per your requirement.
  • Most of the time you keep class member as a private and add get/set functions to encapsulate. This helps in maintenance of code.
  • Generally private function is used when you want to keep your public functions modular or to eliminate repeated code instead of writing whole code in to single function. This helps in maintenance of code.

Refer this link for more detail.

What is the difference between Digest and Basic Authentication?

Let us see the difference between the two HTTP authentication using Wireshark (Tool to analyse packets sent or received) .

1. Http Basic Authentication

Basic

As soon as the client types in the correct username:password,as requested by the Web-server, the Web-Server checks in the Database if the credentials are correct and gives the access to the resource .

Here is how the packets are sent and received :

enter image description here In the first packet the Client fill the credentials using the POST method at the resource - lab/webapp/basicauth .In return the server replies back with http response code 200 ok ,i.e, the username:password were correct .

Detail of HTTP packet

Now , In the Authorization header it shows that it is Basic Authorization followed by some random string .This String is the encoded (Base64) version of the credentials admin:aadd (including colon ) .

2 . Http Digest Authentication(rfc 2069)

So far we have seen that the Basic Authentication sends username:password in plaintext over the network .But the Digest Auth sends a HASH of the Password using Hash algorithm.

Here are packets showing the requests made by the client and response from the server .

Digest

As soon as the client types the credentials requested by the server , the Password is converted to a response using an algorithm and then is sent to the server , If the server Database has same response as given by the client the server gives the access to the resource , otherwise a 401 error .

Detailed digest auth packet In the above Authorization , the response string is calculated using the values of Username,Realm,Password,http-method,URI and Nonce as shown in the image :

Response algorithm (colons are included)

Hence , we can see that the Digest Authentication is more Secure as it involve Hashing (MD5 encryption) , So the packet sniffer tools cannot sniff the Password although in Basic Auth the exact Password was shown on Wireshark.

How to get a list of user accounts using the command line in MySQL?

to avoid repetitions of users when they connect from different origin:

select distinct User from mysql.user;

Is it possible to set transparency in CSS3 box-shadow?

I suppose rgba() would work here. After all, browser support for both box-shadow and rgba() is roughly the same.

/* 50% black box shadow */
box-shadow: 10px 10px 10px rgba(0, 0, 0, 0.5);

_x000D_
_x000D_
div {_x000D_
    width: 200px;_x000D_
    height: 50px;_x000D_
    line-height: 50px;_x000D_
    text-align: center;_x000D_
    color: white;_x000D_
    background-color: red;_x000D_
    margin: 10px;_x000D_
}_x000D_
_x000D_
div.a {_x000D_
  box-shadow: 10px 10px 10px #000;_x000D_
}_x000D_
_x000D_
div.b {_x000D_
  box-shadow: 10px 10px 10px rgba(0, 0, 0, 0.5);_x000D_
}
_x000D_
<div class="a">100% black shadow</div>_x000D_
<div class="b">50% black shadow</div>
_x000D_
_x000D_
_x000D_

Download File to server from URL

prodigitalson's answer didn't work for me. I got missing fopen in CURLOPT_FILE more details.

This worked for me, including local urls:

function downloadUrlToFile($url, $outFileName)
{   
    if(is_file($url)) {
        copy($url, $outFileName); 
    } else {
        $options = array(
          CURLOPT_FILE    => fopen($outFileName, 'w'),
          CURLOPT_TIMEOUT =>  28800, // set this to 8 hours so we dont timeout on big files
          CURLOPT_URL     => $url
        );

        $ch = curl_init();
        curl_setopt_array($ch, $options);
        curl_exec($ch);
        curl_close($ch);
    }
}

How do I detect what .NET Framework versions and service packs are installed?

There is a GUI tool available, ASoft .NET Version Detector, which has always proven highly reliable. It can create XML files by specifying the file name of the XML output on the command line.

You could use this for automation. It is a tiny program, written in a non-.NET dependent language and does not require installation.

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

I also needed build-essential installed:

sudo apt-get install build-essential

Disable developer mode extensions pop up in Chrome

There is an alternative solution, use Chrome-Developer-Mode-Extension-Warning-Patcher:

  1. Download the latest release from here from Github.
  2. Close Chrome.
  3. Unpack the zip archive and run ChromeDevExtWarningPatcher.exe as administrator.
  4. Select your Chrome installation from the just opened GUI and then click on Patch button:

enter image description here

  1. Enjoy Chrome without any DevMode pop-up!

Docker error response from daemon: "Conflict ... already in use by container"

It looks like a container with the name qgis-desktop-2-4 already exists in the system. You can check the output of the below command to confirm if it indeed exists:

$ docker ps -a

The last column in the above command's output is for names.

If the container exists, remove it using:

$ docker rm qgis-desktop-2-4

Or forcefully using,

$ docker rm -f qgis-desktop-2-4

And then try creating a new container.

Apache SSL Configuration Error (SSL Connection Error)

I encounter this problem, because I have <VirtualHost> defined both in httpd.conf and httpd-ssl.conf.

in httpd.conf, it's defined as

<VirtualHost localhost>

in httpd-ssl.conf, it's defined as

<VirtualHost _default_:443>

The following change solved this problem, add :80 in httpd.conf

<VirtualHost localhost:80>

Safe navigation operator (?.) or (!.) and null property paths

Building on @Pvl's answer, you can include type safety on your returned value as well if you use overrides:

function dig<
  T,
  K1 extends keyof T
  >(obj: T, key1: K1): T[K1];

function dig<
  T,
  K1 extends keyof T,
  K2 extends keyof T[K1]
  >(obj: T, key1: K1, key2: K2): T[K1][K2];

function dig<
  T,
  K1 extends keyof T,
  K2 extends keyof T[K1],
  K3 extends keyof T[K1][K2]
  >(obj: T, key1: K1, key2: K2, key3: K3): T[K1][K2][K3];

function dig<
  T,
  K1 extends keyof T,
  K2 extends keyof T[K1],
  K3 extends keyof T[K1][K2],
  K4 extends keyof T[K1][K2][K3]
  >(obj: T, key1: K1, key2: K2, key3: K3, key4: K4): T[K1][K2][K3][K4];

function dig<
  T,
  K1 extends keyof T,
  K2 extends keyof T[K1],
  K3 extends keyof T[K1][K2],
  K4 extends keyof T[K1][K2][K3],
  K5 extends keyof T[K1][K2][K3][K4]
  >(obj: T, key1: K1, key2: K2, key3: K3, key4: K4, key5: K5): T[K1][K2][K3][K4][K5];

function dig<
  T,
  K1 extends keyof T,
  K2 extends keyof T[K1],
  K3 extends keyof T[K1][K2],
  K4 extends keyof T[K1][K2][K3],
  K5 extends keyof T[K1][K2][K3][K4]
  >(obj: T, key1: K1, key2?: K2, key3?: K3, key4?: K4, key5?: K5):
  T[K1] |
  T[K1][K2] |
  T[K1][K2][K3] |
  T[K1][K2][K3][K4] |
  T[K1][K2][K3][K4][K5] {
    let value: any = obj && obj[key1];

    if (key2) {
      value = value && value[key2];
    }

    if (key3) {
      value = value && value[key3];
    }

    if (key4) {
      value = value && value[key4];
    }

    if (key5) {
      value = value && value[key5];
    }

    return value;
}

Example on playground.

C++11 introduced a standardized memory model. What does it mean? And how is it going to affect C++ programming?

For languages not specifying a memory model, you are writing code for the language and the memory model specified by the processor architecture. The processor may choose to re-order memory accesses for performance. So, if your program has data races (a data race is when it's possible for multiple cores / hyper-threads to access the same memory concurrently) then your program is not cross platform because of its dependence on the processor memory model. You may refer to the Intel or AMD software manuals to find out how the processors may re-order memory accesses.

Very importantly, locks (and concurrency semantics with locking) are typically implemented in a cross platform way... So if you are using standard locks in a multithreaded program with no data races then you don't have to worry about cross platform memory models.

Interestingly, Microsoft compilers for C++ have acquire / release semantics for volatile which is a C++ extension to deal with the lack of a memory model in C++ http://msdn.microsoft.com/en-us/library/12a04hfd(v=vs.80).aspx. However, given that Windows runs on x86 / x64 only, that's not saying much (Intel and AMD memory models make it easy and efficient to implement acquire / release semantics in a language).

Access PHP variable in JavaScript

I'm not sure how necessary this is, and it adds a call to getElementById, but if you're really keen on getting inline JavaScript out of your code, you can pass it as an HTML attribute, namely:

<span class="metadata" id="metadata-size-of-widget" title="<?php echo json_encode($size_of_widget) ?>"></span>

And then in your JavaScript:

var size_of_widget = document.getElementById("metadata-size-of-widget").title;

Authentication issues with WWW-Authenticate: Negotiate

Putting this information here for future readers' benefit.

  • 401 (Unauthorized) response header -> Request authentication header

  • Here are several WWW-Authenticate response headers. (The full list is at IANA: HTTP Authentication Schemes.)

    • WWW-Authenticate: Basic-> Authorization: Basic + token - Use for basic authentication
    • WWW-Authenticate: NTLM-> Authorization: NTLM + token (2 challenges)
    • WWW-Authenticate: Negotiate -> Authorization: Negotiate + token - used for Kerberos authentication
      • By the way: IANA has this angry remark about Negotiate: This authentication scheme violates both HTTP semantics (being connection-oriented) and syntax (use of syntax incompatible with the WWW-Authenticate and Authorization header field syntax).

You can set the Authorization: Basic header only when you also have the WWW-Authenticate: Basic header on your 401 challenge.

But since you have WWW-Authenticate: Negotiate this should be the case for Kerberos based authentication.

how to call a method in another Activity from Activity

public class ActivityB extends AppCompatActivity {

static Context mContext;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_b);

    try {

        Bundle bundle = getIntent().getExtras();
        if (bundle != null) {
            String texto = bundle.getString("message");
            if (texto != null) {
              //code....
            }

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    public static void launch(String message) {
        Intent intent = new Intent(mContext, ActivityB.class);
        intent.putExtra("message", message);
        mContext.startActivity(intent);
    }
}

In ActivityA or Service.

public class Service extends Service{

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {    

        String text = "Value to send";
        ActivityB.launch(text);
        Log.d(TAG, text);
    }
}

ssh_exchange_identification: Connection closed by remote host under Git bash

For fixing the issues add the Hostname for Git on ~/.ssh/config,

Host github.com
 Hostname ssh.github.com
 Port 443

In my case github!

"Javac" doesn't work correctly on Windows 10

Add

PATH = C:\Program Files\Java\jdk1.8.0_66\bin 

in Advanced system setting. Then Choose Environment Variable.

Apache HttpClient Interim Error: NoHttpResponseException

Accepted answer is right but lacks solution. To avoid this error, you can add setHttpRequestRetryHandler (or setRetryHandler for apache components 4.4) for your HTTP client like in this answer.

How to enable named/bind/DNS full logging?

Run command rndc querylog on or add querylog yes; to options{}; section in named.conf to activate that channel.

Also make sure you’re checking correct directory if your bind is chrooted.

Pseudo-terminal will not be allocated because stdin is not a terminal

Also with option -T from manual

Disable pseudo-tty allocation

Char array declaration and initialization in C

Yes, this is a kind of inconsistency in the language.

The "=" in myarray = "abc"; is assignment (which won't work as the array is basically a kind of constant pointer), whereas in char myarray[4] = "abc"; it's an initialization of the array. There's no way for "late initialization".

You should just remember this rule.

How to show disable HTML select option in by default?

Electron + React Let your two first options be like this

<option hidden="true>Choose Tagging</option>
<option disabled="disabled" default="true">Choose Tagging</option>

First to display when closed Second to display first when the list opens

Table cell widths - fixing width, wrapping/truncating long words

try td {background-color:white}

It just worked for a column I didn't want to get trampled by a previous column's long text.

Creating an instance of class

  1. Allocates some dynamic memory from the free store, and creates an object in that memory using its default constructor. You never delete it, so the memory is leaked.
  2. Does exactly the same as 1; in the case of user-defined types, the parentheses are optional.
  3. Allocates some automatic memory, and creates an object in that memory using its default constructor. The memory is released automatically when the object goes out of scope.
  4. Similar to 3. Notionally, the named object foo4 is initialised by default-constructing, copying and destroying a temporary object; usually, this is elided giving the same result as 3.
  5. Allocates a dynamic object, then initialises a second by copying the first. Both objects are leaked; and there's no way to delete the first since you don't keep a pointer to it.
  6. Does exactly the same as 5.
  7. Does not compile. Foo foo5 is a declaration, not an expression; function (and constructor) arguments must be expressions.
  8. Creates a temporary object, and initialises a dynamic object by copying it. Only the dynamic object is leaked; the temporary is destroyed automatically at the end of the full expression. Note that you can create the temporary with just Foo() rather than the equivalent Foo::Foo() (or indeed Foo::Foo::Foo::Foo::Foo())

When do I use each?

  1. Don't, unless you like unnecessary decorations on your code.
  2. When you want to create an object that outlives the current scope. Remember to delete it when you've finished with it, and learn how to use smart pointers to control the lifetime more conveniently.
  3. When you want an object that only exists in the current scope.
  4. Don't, unless you think 3 looks boring and what to add some unnecessary decoration.
  5. Don't, because it leaks memory with no chance of recovery.
  6. Don't, because it leaks memory with no chance of recovery.
  7. Don't, because it won't compile
  8. When you want to create a dynamic Bar from a temporary Foo.

how to set default culture info for entire c# application

If you use a Language Resource file to set the labels in your application you need to set the its value:

CultureInfo customCulture = new CultureInfo("en-US");
Languages.Culture = customCulture;

What is the difference between a symbolic link and a hard link?

Simply , Hard link : is just add new name to a file, that's mean , a file can have many name in the same time, all name are equal to each other, no one preferred, Hard link is not mean to copy the all contents of file and make new file is not that, it just create an alternative name to be known..

Symbolic link (symlink) : is a file pointer to another file, if the symbolic link points to an existing file which is later deleted, the symbolic link continues to point to the same file name even though the name no longer names any file.

Android: Clear the back stack

As per Wakka in Removing an activity from the history stack...


Add android:noHistory="true" attribute to your <activity> in the AndroidManifest.xml like this:

    <activity android:name=".MyActivity"
        android:noHistory="true">
    </activity>

What is the difference between active and passive FTP?

I recently run into this question in my work place so I think I should say something more here. I will use image to explain how the FTP works as an additional source for previous answer.

Active mode:

active mode


Passive mode:

enter image description here


In an active mode configuration, the server will attempt to connect to a random client-side port. So chances are, that port wouldn't be one of those predefined ports. As a result, an attempt to connect to it will be blocked by the firewall and no connection will be established.

enter image description here


A passive configuration will not have this problem since the client will be the one initiating the connection. Of course, it's possible for the server side to have a firewall too. However, since the server is expected to receive a greater number of connection requests compared to a client, then it would be but logical for the server admin to adapt to the situation and open up a selection of ports to satisfy passive mode configurations.

So it would be best for you to configure server to support passive mode FTP. However, passive mode would make your system vulnerable to attacks because clients are supposed to connect to random server ports. Thus, to support this mode, not only should your server have to have multiple ports available, your firewall should also allow connections to all those ports to pass through!

To mitigate the risks, a good solution would be to specify a range of ports on your server and then to allow only that range of ports on your firewall.

For more information, please read the official document.

Getting min and max Dates from a pandas dataframe

'Date' is your index so you want to do,

print (df.index.min())
print (df.index.max())

2014-03-13 00:00:00
2014-03-31 00:00:00

Why is "throws Exception" necessary when calling a function?

Java requires that you handle or declare all exceptions. If you are not handling an Exception using a try/catch block then it must be declared in the method's signature.

For example:

class throwseg1 {
    void show() throws Exception {
        throw new Exception();
    }
}

Should be written as:

class throwseg1 {
    void show() {
        try {
            throw new Exception();
        } catch(Exception e) {
            // code to handle the exception
        }
    }
}

This way you can get rid of the "throws Exception" declaration in the method declaration.

How to remove focus border (outline) around text/input boxes? (Chrome)

<input style="border:none" >

Worked well for me. Wished to have it fixed in html itself ... :)

Click through div to underlying elements

I think the event.stopPropagation(); should be mentioned here as well. Add this to the Click function of your button.

Prevents the event from bubbling up the DOM tree, preventing any parent handlers from being notified of the event.

How to make a Java Generic method static?

I'll explain it in a simple way.

Generics defined at Class level are completely separate from the generics defined at the (static) method level.

class Greet<T> {

    public static <T> void sayHello(T obj) {
        System.out.println("Hello " + obj);
    }
}

When you see the above code anywhere, please note that the T defined at the class level has nothing to do with the T defined in the static method. The following code is also completely valid and equivalent to the above code.

class Greet<T> {

    public static <E> void sayHello(E obj) {
        System.out.println("Hello " + obj);
    }
}

Why the static method needs to have its own generics separate from those of the Class?

This is because, the static method can be called without even instantiating the Class. So if the Class is not yet instantiated, we do not yet know what is T. This is the reason why the static methods needs to have its own generics.

So, whenever you are calling the static method,

Greet.sayHello("Bob");
Greet.sayHello(123);

JVM interprets it as the following.

Greet.<String>sayHello("Bob");
Greet.<Integer>sayHello(123);

Both giving the same outputs.

Hello Bob
Hello 123

moving committed (but not pushed) changes to a new branch after pull

If you have a low # of commits and you don't care if these are combined into one mega-commit, this works well and isn't as scary as doing git rebase:

unstage the files (replace 1 with # of commits)

git reset --soft HEAD~1

create a new branch

git checkout -b NewBranchName

add the changes

git add -A

make a commit

git commit -m "Whatever"

How to make a launcher

They're examples provided by the Android team, if you've already loaded Samples, you can import Home screen replacement sample by following these steps.

File > New > Other >Android > Android Sample Project > Android x.x > Home > Finish

But if you do not have samples loaded, then download it using the below steps

Windows > Android SDK Manager > chooses "Sample for SDK" for SDK you need it > Install package > Accept License > Install

Getting datarow values into a string?

I've done this a lot myself. If you just need a comma separated list for all of row values you can do this:

StringBuilder sb = new StringBuilder();
foreach (DataRow row in results.Tables[0].Rows)     
{
    sb.AppendLine(string.Join(",", row.ItemArray));
}

A StringBuilder is the preferred method as string concatenation is significantly slower for large amounts of data.

String Concatenation in EL

it also can be a great idea using concat for EL + MAP + JSON problem like in this example :

#{myMap[''.concat(myid)].content}

Error ITMS-90717: "Invalid App Store Icon"

I faced the same problem and wasn't able to fix it with the provided solution by Shamsudheen TK. Ionic somehow added transparency to my icons even if the source icon did not have any transparency at all. In the end I was able to resolve it by:

Install imagemagick (MacOS):

brew install imagemagick

Remove alpha channel from all images in resource folder:

find ./resources/ -name "*.png" -exec convert "{}" -alpha off "{}" \;

Make a UIButton programmatically in Swift

UIButton with constraints in iOS 9.1/Xcode 7.1.1/Swift 2.1:

import UIKit
import MapKit

class MapViewController: UIViewController {  

    override func loadView() {
        mapView = MKMapView()  //Create a view...
        view = mapView         //assign it to the ViewController's (inherited) view property.
                               //Equivalent to self.view = mapView

        myButton = UIButton(type: .RoundedRect)  //RoundedRect is an alias for System (tested by printing out their rawValue's)
        //myButton.frame = CGRect(x:50, y:500, width:70, height:50)  //Doesn't seem to be necessary when using constraints.
        myButton.setTitle("Current\nLocation", forState: .Normal)
        myButton.titleLabel?.lineBreakMode = .ByWordWrapping  //If newline in title, split title onto multiple lines
        myButton.titleLabel?.textAlignment = .Center
        myButton.setTitleColor(UIColor.whiteColor(), forState: .Normal)
        myButton.layer.cornerRadius = 6   //For some reason, a button with type RoundedRect has square corners
        myButton.backgroundColor = UIColor.redColor().colorWithAlphaComponent(0.5) //Make the color partially transparent
        //Attempt to add padding around text. Shrunk the frame when I tried it.  Negative values had no effect.
        //myButton.titleEdgeInsets = UIEdgeInsetsMake(-10,-10,-10,-10)
        myButton.contentEdgeInsets = UIEdgeInsetsMake(5,5,5,5)  //Add padding around text.

        myButton.addTarget(self, action: "getCurrentLocation:", forControlEvents: .TouchUpInside)
        mapView.addSubview(myButton)

        //Button Constraints:
        myButton.translatesAutoresizingMaskIntoConstraints = false //***
        //bottomLayoutGuide(for tab bar) and topLayoutGuide(for status bar) are properties of the ViewController
        //To anchor above the tab bar on the bottom of the screen:
        let bottomButtonConstraint = myButton.bottomAnchor.constraintEqualToAnchor(bottomLayoutGuide.topAnchor, constant: -20) //Implied call of self.bottomLayoutGuide. Anchor 20 points **above** the top of the tab bar.
        //To anchor to the blue guide line that is inset from the left 
        //edge of the screen in InterfaceBuilder:
        let margins = view.layoutMarginsGuide  //Now the guide is a property of the View.
        let leadingButtonConstraint = myButton.leadingAnchor.constraintEqualToAnchor(margins.leadingAnchor)

        bottomButtonConstraint.active = true
        leadingButtonConstraint.active = true
    }


    func getCurrentLocation(sender: UIButton) {
        print("Current Location button clicked!")
    }

The button is anchored to the bottom left corner, above the tab bar.

How to sum the values of a JavaScript object?

Any reason you're not just using a simple for...in loop?

var sample = { a: 1 , b: 2 , c:3 };
var summed = 0;

for (var key in sample) {
    summed += sample[key];
};

http://jsfiddle.net/vZhXs/

Why does an SSH remote command get fewer environment variables then when run manually?

I had similar issue, but in the end I found out that ~/.bashrc was all I needed.

However, in Ubuntu, I had to comment the line that stops processing ~/.bashrc :

#If not running interactively, don't do anything
[ -z "$PS1" ] && return

The split() method in Java does not work on a dot (.)

Try:

String words[]=temp.split("\\.");

The method is:

String[] split(String regex) 

"." is a reserved char in regex

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

You can do it using Primefaces like this :

<p:button 
      outcome="/page2.xhtml?faces-redirect=true&amp;id=#{myBean.id}">
</p:button>

Get the value of bootstrap Datetimepicker in JavaScript

I'm using the latest Bootstrap 3 DateTime Picker (http://eonasdan.github.io/bootstrap-datetimepicker/)

This is how you should use DateTime Picker inline:

var selectedDate = $("#datetimepicker").find(".active").data("day");

The above returned: 03/23/2017

Can I make a phone call from HTML on Android?

Yes you can; it works on Android too:

tel: phone_number
Calls the entered phone number. Valid telephone numbers as defined in the IETF RFC 3966 are accepted. Valid examples include the following:

* tel:2125551212
* tel: (212) 555 1212

The Android browser uses the Phone app to handle the “tel” scheme, as defined by RFC 3966.
Clicking a link like:

<a href="tel:2125551212">2125551212</a>

on Android will bring up the Phone app and pre-enter the digits for 2125551212 without autodialing.

Have a look to RFC3966

Forking vs. Branching in GitHub

It has to do with the general workflow of Git. You're unlikely to be able to push directly to the main project's repository. I'm not sure if GitHub project's repository support branch-based access control, as you wouldn't want to grant anyone the permission to push to the master branch for example.

The general pattern is as follows:

  • Fork the original project's repository to have your own GitHub copy, to which you'll then be allowed to push changes.
  • Clone your GitHub repository onto your local machine
  • Optionally, add the original repository as an additional remote repository on your local repository. You'll then be able to fetch changes published in that repository directly.
  • Make your modifications and your own commits locally.
  • Push your changes to your GitHub repository (as you generally won't have the write permissions on the project's repository directly).
  • Contact the project's maintainers and ask them to fetch your changes and review/merge, and let them push back to the project's repository (if you and them want to).

Without this, it's quite unusual for public projects to let anyone push their own commits directly.

How to set the action for a UIBarButtonItem in Swift

As of Swift 2.2, there is a special syntax for compiler-time checked selectors. It uses the syntax: #selector(methodName).

Swift 3 and later:

var b = UIBarButtonItem(
    title: "Continue",
    style: .plain,
    target: self,
    action: #selector(sayHello(sender:))
)

func sayHello(sender: UIBarButtonItem) {
}

If you are unsure what the method name should look like, there is a special version of the copy command that is very helpful. Put your cursor somewhere in the base method name (e.g. sayHello) and press Shift+Control+Option+C. That puts the ‘Symbol Name’ on your keyboard to be pasted. If you also hold Command it will copy the ‘Qualified Symbol Name’ which will include the type as well.

Swift 2.3:

var b = UIBarButtonItem(
    title: "Continue",
    style: .Plain,
    target: self,
    action: #selector(sayHello(_:))
)

func sayHello(sender: UIBarButtonItem) {
}

This is because the first parameter name is not required in Swift 2.3 when making a method call.

You can learn more about the syntax on swift.org here: https://swift.org/blog/swift-2-2-new-features/#compile-time-checked-selectors

How to pass command line arguments to a shell alias?

Just to reiterate what has been posted for other shells, in Bash the following works:

alias blah='function _blah(){ echo "First: $1"; echo "Second: $2"; };_blah'

Running the following:

blah one two

Gives the output below:

First: one
Second: two

How do I replace all line breaks in a string with <br /> elements?

If the accepted answer isn't working right for you then you might try.

str.replace(new RegExp('\n','g'), '<br />')

It worked for me.

Could not find a base address that matches scheme https for the endpoint with binding WebHttpBinding. Registered base address schemes are [http]

In the endpoint tag you need to include the property address=""

<endpoint address="" binding="webHttpBinding" bindingConfiguration="SecureBasicRest" behaviorConfiguration="svcEndpoint" name="webHttp" contract="SvcContract.Authenticate" />

How to delete a module in Android Studio

After doing what's referred in [this answer]: https://stackoverflow.com/a/24592192/82788

Select the module(since it's still visible on the Project view),pressing Delete button on the keyboard can delete this module on disk.(Before doing what's referred in that answer, the Delete button has no effect.)

How to install plugin for Eclipse from .zip

It depends on what the zip contains. Take a look to see if it got content.jar and artifacts.jar. If it does, it is an archived updated site. Install from it the same way as you install from a remote site.

If the zip doesn't contain content.jar and artifacts.jar, go to your Eclipse install's dropins directory, create a subfolder (name doesn't matter) and expand your zip into that folder. Restart Eclipse.

What does "Use of unassigned local variable" mean?

There are many paths through your code whereby your variables are not initialized, which is why the compiler complains.

Specifically, you are not validating the user input for creditPlan - if the user enters a value of anything else than "0","1","2" or "3", then none of the branches indicated will be executed (and creditPlan will not be defaulted to zero as per your user prompt).

As others have mentioned, the compiler error can be avoided by either a default initialization of all derived variables before the branches are checked, OR ensuring that at least one of the branches is executed (viz, mutual exclusivity of the branches, with a fall through else statement).

I would however like to point out other potential improvements:

  • Validate user input before you trust it for use in your code.
  • Model the parameters as a whole - there are several properties and calculations applicable to each plan.
  • Use more appropriate types for data. e.g. CreditPlan appears to have a finite domain and is better suited to an enumeration or Dictionary than a string. Financial data and percentages should always be modelled as decimal, not double to avoid rounding issues, and 'status' appears to be a boolean.
  • DRY up repetitive code. The calculation, monthlyCharge = balance * annualRate * (1/12)) is common to more than one branch. For maintenance reasons, do not duplicate this code.
  • Possibly more advanced, but note that Functions are now first class citizens of C#, so you can assign a function or lambda as a property, field or parameter!.

e.g. here is an alternative representation of your model:

    // Keep all Credit Plan parameters together in a model
    public class CreditPlan
    {
        public Func<decimal, decimal, decimal> MonthlyCharge { get; set; }
        public decimal AnnualRate { get; set; }
        public Func<bool, Decimal> LateFee { get; set; }
    }

    // DRY up repeated calculations
    static private decimal StandardMonthlyCharge(decimal balance, decimal annualRate)
    { 
       return balance * annualRate / 12;
    }

    public static Dictionary<int, CreditPlan> CreditPlans = new Dictionary<int, CreditPlan>
    {
        { 0, new CreditPlan
            {
                AnnualRate = .35M, 
                LateFee = _ => 0.0M, 
                MonthlyCharge = StandardMonthlyCharge
            }
        },
        { 1, new CreditPlan
            {
                AnnualRate = .30M, 
                LateFee = late => late ? 0 : 25.0M,
                MonthlyCharge = StandardMonthlyCharge
            }
        },
        { 2, new CreditPlan
            {
                AnnualRate = .20M, 
                LateFee = late => late ? 0 : 35.0M,
                MonthlyCharge = (balance, annualRate) => balance > 100 
                    ? balance * annualRate / 12
                    : 0
            }
        },
        { 3, new CreditPlan
            {
                AnnualRate = .15M, 
                LateFee = _ => 0.0M,
                MonthlyCharge = (balance, annualRate) => balance > 500 
                    ? (balance - 500) * annualRate / 12
                    : 0
            }
        }
    };

How to get the user input in Java?

To read a line or a string, you can use a BufferedReader object combined with an InputStreamReader one as follows:

BufferedReader bufferReader = new BufferedReader(new InputStreamReader(System.in));
String inputLine = bufferReader.readLine();

sql query to find the duplicate records

This query uses the Group By and and Having clauses to allow you to select (locate and list out) for each duplicate record. The As clause is a convenience to refer to Quantity in the select and Order By clauses, but is not really part of getting you the duplicate rows.

Select
    Title,
    Count( Title ) As [Quantity]
   From
    Training
   Group By
    Title
   Having 
    Count( Title ) > 1
   Order By
    Quantity desc

What is `git push origin master`? Help with git's refs, heads and remotes

Or as a single command:

git push -u origin master:my_test

Pushes the commits from your local master branch to a (possibly new) remote branch my_test and sets up master to track origin/my_test.

How do I export a project in the Android studio?

Firstly, Add this android:debuggable="false" in the application tag of the AndroidManifest.xml.

You don't need to harcode android:debuggable="false" in your application tag. Infact for me studio complaints -

Avoid hardcoding the debug mode; leaving it out allows debug and release builds to automatically assign one less... (Ctrl+F1)

It's best to leave out the android:debuggable attribute from the manifest. If you do, then the tools will automatically insert android:debuggable=true when building an APK to debug on an emulator or device. And when you perform a release build, such as Exporting APK, it will automatically set it to false. If on the other hand you specify a specific value in the manifest file, then the tools will always use it. This can lead to accidentally publishing your app with debug information.

The accepted answer looks somewhat old. For me it asks me to select whether I want debug build or release build.

Go to Build->Generate Signed APK. Select your keystore, provide keystore password etc.

enter image description here

Now you should see a prompt to select release build or debug build.

For production always select release build!

enter image description here

And you are done. Signed APK exported.

enter image description here

PS : Don't forget to increment your versionCode in manifest file before uploading to playstore :)

How to construct a std::string from a std::vector<char>?

std::string s(v.begin(), v.end());

Where v is pretty much anything iterable. (Specifically begin() and end() must return InputIterators.)

Bootstrap modal - close modal when "call to action" button is clicked

I tried closing a modal window with a bootstrap CSS loaded. The close () method does not really close the modal window. So I added the display style to "none".

    function closeDialog() {
        let d = document.getElementById('d')
        d.style.display = "none"
        d.close()
    }

The HTML code includes a button into the dialog window.

<input type="submit" value="Confirm" onclick="closeDialog()"/>

How to search a specific value in all tables (PostgreSQL)?

to search every column of every table for a particular value

This does not define how to match exactly.
Nor does it define what to return exactly.

Assuming:

  • Find any row with any column containing the given value in its text representation - as opposed to equaling the given value.
  • Return the table name (regclass) and the tuple ID (ctid), because that's simplest.

Here is a dead simple, fast and slightly dirty way:

CREATE OR REPLACE FUNCTION search_whole_db(_like_pattern text)
  RETURNS TABLE(_tbl regclass, _ctid tid) AS
$func$
BEGIN
   FOR _tbl IN
      SELECT c.oid::regclass
      FROM   pg_class c
      JOIN   pg_namespace n ON n.oid = relnamespace
      WHERE  c.relkind = 'r'                           -- only tables
      AND    n.nspname !~ '^(pg_|information_schema)'  -- exclude system schemas
      ORDER BY n.nspname, c.relname
   LOOP
      RETURN QUERY EXECUTE format(
         'SELECT $1, ctid FROM %s t WHERE t::text ~~ %L'
       , _tbl, '%' || _like_pattern || '%')
      USING _tbl;
   END LOOP;
END
$func$  LANGUAGE plpgsql;

Call:

SELECT * FROM search_whole_db('mypattern');

Provide the search pattern without enclosing %.

Why slightly dirty?

If separators and decorators for the row in text representation can be part of the search pattern, there can be false positives:

  • column separator: , by default
  • whole row is enclosed in parentheses:()
  • some values are enclosed in double quotes "
  • \ may be added as escape char

And the text representation of some columns may depend on local settings - but that ambiguity is inherent to the question, not to my solution.

Each qualifying row is returned once only, even when it matches multiple times (as opposed to other answers here).

This searches the whole DB except for system catalogs. Will typically take a long time to finish. You might want to restrict to certain schemas / tables (or even columns) like demonstrated in other answers. Or add notices and a progress indicator, also demonstrated in another answer.

The regclass object identifier type is represented as table name, schema-qualified where necessary to disambiguate according to the current search_path:

What is the ctid?

You might want to escape characters with special meaning in the search pattern. See:

JavaScript isset() equivalent

Try to create function like empty function of PHP in Javascript. May this helps.

function empty(str){
  try{
    if(typeof str==="string"){
        str=str.trim();
    }
    return !(str !== undefined && str !== "undefined" && str !== null && str!=="" && str!==0 && str!==false);
  }catch(ex){
    return true;
  }
 }

console.log(empty(0))//true
console.log(empty(null))//true
console.log(empty(" "))//true
console.log(empty(""))//true
console.log(empty(undefined))//true
console.log(empty("undefined"))//true

var tmp=1;
console.log(empty(tmp))//false

var tmp="Test";
console.log(empty(tmp))//false

var tmp=" Test ";
console.log(empty(tmp))//false

var tmp={a:1,b:false,c:0};
console.log(empty(tmp.a))//false
console.log(empty(tmp.b))//true
console.log(empty(tmp.c))//true
console.log(empty(tmp.c))//true
console.log(empty(tmp.c.d))//true

Python: Assign print output to a variable

Please note, I wrote this answer based on Python 3.x. No worries you can assign print() statement to the variable like this.

>>> var = print('some text')
some text
>>> var
>>> type(var)
<class 'NoneType'>

According to the documentation,

All non-keyword arguments are converted to strings like str() does and written to the stream, separated by sep and followed by end. Both sep and end must be strings; they can also be None, which means to use the default values. If no objects are given, print() will just write end.

The file argument must be an object with a write(string) method; if it is not present or None, sys.stdout will be used. Since printed arguments are converted to text strings, print() cannot be used with binary mode file objects. For these, use file.write(...) instead.

That's why we cannot assign print() statement values to the variable. In this question you have ask (or any function). So print() also a function with the return value with None. So the return value of python function is None. But you can call the function(with parenthesis ()) and save the return value in this way.

>>> var = some_function()

So the var variable has the return value of some_function() or the default value None. According to the documentation about print(), All non-keyword arguments are converted to strings like str() does and written to the stream. Lets look what happen inside the str().

Return a string version of object. If object is not provided, returns the empty string. Otherwise, the behavior of str() depends on whether encoding or errors is given, as follows.

So we get a string object, then you can modify the below code line as follows,

>>> var = str(some_function())

or you can use str.join() if you really have a string object.

Return a string which is the concatenation of the strings in iterable. A TypeError will be raised if there are any non-string values in iterable, including bytes objects. The separator between elements is the string providing this method.

change can be as follows,

>>> var = ''.join(some_function())  # you can use this if some_function() really returns a string value

Regular expression for decimal number

\d{1}(\.\d{1,3})?

Match a single digit 0..9 «\d{1}»
   Exactly 1 times «{1}»
Match the regular expression below and capture its match into backreference number 1 «(\.\d{1,3})?»
   Between zero and one times, as many times as possible, giving back as needed (greedy) «?»
   Match the character “.” literally «\.»
   Match a single digit 0..9 «\d{1,3}»
      Between one and 3 times, as many times as possible, giving back as needed (greedy) «{1,3}»


Created with RegexBuddy

Matches:
1
1.2
1.23
1.234

installation app blocked by play protect

the only solution worked for me was using java keytool and generating a .keystore file the command line and then use that .keystore file to sign my app

you can find the java keytool at this directory C:\Program Files\Java\jre7\bin

open a command window and switch to that directory and enter a command like this

keytool -genkey -v -keystore my-release-key.keystore -alias alias_name -keyalg RSA -keysize 2048 -validity 10000

Keytool prompts you to provide passwords for the keystore, your name , company etc . note that at the last prompt you need to enter yes.

It then generates the keystore as a file called my-release-key.keystore in the directory you're in. The keystore and key are protected by the passwords you entered. The keystore contains a single key, valid for 10000 days. The alias is a name that you — will use later, to refer to this keystore when signing your application.

For more information about Keytool, see the documentation at: http://docs.oracle.com/javase/6/docs/technotes/tools/windows/keytool.html

and for more information on signing Android apps go here: http://developer.android.com/tools/publishing/app-signing.html

Can I add a UNIQUE constraint to a PostgreSQL table, after it's already created?

psql's inline help:

\h ALTER TABLE

Also documented in the postgres docs (an excellent resource, plus easy to read, too).

ALTER TABLE tablename ADD CONSTRAINT constraintname UNIQUE (columns);

ojdbc14.jar vs. ojdbc6.jar

The "14" and "6" in those driver names refer to the JVM they were written for. If you're still using JDK 1.4 I'd say you have a serious problem and need to upgrade. JDK 1.4 is long past its useful support life. It didn't even have generics! JDK 6 u21 is the current production standard from Oracle/Sun. I'd recommend switching to it if you haven't already.

How do you trigger a block after a delay, like -performSelector:withObject:afterDelay:?

You can either wrap the argument in your own class, or wrap the method call in a method that doesn't need to be passed in the primitive type. Then call that method after your delay, and within that method perform the selector you wish to perform.

how to add css class to html generic control div?

If you're going to be repeating this, might as well have an extension method:

// appends a string class to the html controls class attribute
public static void AddClass(this HtmlControl control, string newClass)
{
    if (control.Attributes["class"].IsNotNullAndNotEmpty())
    {
        control.Attributes["class"] += " " + newClass;
    }
    else
    {
        control.Attributes["class"] = newClass;
    }
}

Viewing all defined variables

If possible, you may want to use IPython.

To get a list of all current user-defined variables, IPython provides a magic command named who (magics must be prefixed with the modulo character unless the automagic feature is enabled):

In [1]: foo = 'bar'
In [2]: %who
foo

You can use the whos magic to get more detail:

In [3]: %whos
Variable   Type    Data/Info
----------------------------
foo        str     bar

There are a wealth of other magics available. IPython is basically the Python interpreter on steroids. One convenient magic is store, which lets you save variables between sessions (using pickle).

Note: I am not associated with IPython Dev - just a satisfied user.

Edit:

You can find all the magic commands in the IPython Documentation.

This article also has a helpful section on the use of magic commands in Jupyter Notebook

How do you performance test JavaScript code?

I think JavaScript performance (time) testing is quite enough. I found a very handy article about JavaScript performance testing here.

Cannot find module '../build/Release/bson'] code: 'MODULE_NOT_FOUND' } js-bson: Failed to load c++ bson extension, using pure JS version

First copy bson.js code from browser_build folder

second create new file bson.js and paste code

third save the new file near to in index.js.

Double decimal formatting in Java

Use String.format:

String.format("%.2f", 4.52135);

As per docs:

The locale always used is the one returned by Locale.getDefault().

Excel VBA calling sub from another sub with multiple inputs, outputs of different sizes

To call a sub inside another sub you only need to do:

Call Subname()

So where you have CalculateA(Nc,kij, xi, a1, a) you need to have call CalculateA(Nc,kij, xi, a1, a)

As the which runs first problem it's for you to decide, when you want to run a sub you can go to the macro list select the one you want to run and run it, you can also give it a key shortcut, therefore you will only have to press those keys to run it. Although, on secondary subs, I usually do it as Private sub CalculateA(...) cause this way it does not appear in the macro list and it's easier to work

Hope it helps, Bruno

PS: If you have any other question just ask, but this isn't a community where you ask for code, you come here with a question or a code that isn't running and ask for help, not like you did "It would be great if you could write it in the Excel VBA format."

What is the significance of load factor in HashMap?

From the documentation:

The load factor is a measure of how full the hash table is allowed to get before its capacity is automatically increased

It really depends on your particular requirements, there's no "rule of thumb" for specifying an initial load factor.

How do I explicitly specify a Model's table-name mapping in Rails?

Rails >= 3.2 (including Rails 4+ and 5+):

class Countries < ActiveRecord::Base
  self.table_name = "cc"
end

Rails <= 3.1:

class Countries < ActiveRecord::Base
  self.set_table_name "cc"
  ...
end

Convert an array into an ArrayList

As an ArrayList that line would be

import java.util.ArrayList;
...
ArrayList<Card> hand = new ArrayList<Card>();

To use the ArrayList you have do

hand.get(i); //gets the element at position i 
hand.add(obj); //adds the obj to the end of the list
hand.remove(i); //removes the element at position i
hand.add(i, obj); //adds the obj at the specified index
hand.set(i, obj); //overwrites the object at i with the new obj

Also read this http://docs.oracle.com/javase/6/docs/api/java/util/ArrayList.html

How do I compare two Integers?

The Integer class implements Comparable<Integer>, so you could try,

x.compareTo(y) == 0

also, if rather than equality, you are looking to compare these integers, then,

x.compareTo(y) < 0 will tell you if x is less than y.

x.compareTo(y) > 0 will tell you if x is greater than y.

Of course, it would be wise, in these examples, to ensure that x is non-null before making these calls.

jQuery Button.click() event is triggered twice

This can be caused for following reasons:

  1. You have included the script more than once in the same html file
  2. You have added the event listener twice (eg: using onclick attribute on the element and also with jquery
  3. The event is bubbled up to some parent element. (you may consider using event.stopPropagation).
  4. If you use template inheritance like extends in Django, most probably you have included the script in more than one file which are combined together by include or extend template tags
  5. If you are using Django template, you have wrongly placed a block inside another.

So, you should either find them out and remove the duplicate import. It is the best thing to do.

Another solution is to remove all click event listeners first in the script like:

$("#myId").off().on("click", function(event) {
event.stopPropagation();
});

You can skip event.stopPropagation(); if you are sure that the event is not bubbled.

ORA-12514 TNS:listener does not currently know of service requested in connect descriptor

I had also faced the same problem and spent 3 days to dig it out.

This happens because of your wrong TNS service entry.

First check whether you are able to connect to standby database from primary database using sql > sqlplus sys@orastand as sysdba (orastand is a standby database).

If you are not able to connect then it is a problem with the service. Correct the entry of service name in TNS file at primary end.

Check standby database the same way. Make the changes here too if required.

Make sure the log_archive_dest_2 parameter has the correct service name.

Do conditional INSERT with SQL?

Usually you make the thing you don't want duplicates of unique, and allow the database itself to refuse the insert.

Otherwise, you can use INSERT INTO, see How to avoid duplicates in INSERT INTO SELECT query in SQL Server?

Split value from one field to two

Not exactly answering the question, but faced with the same problem I ended up doing this:

UPDATE people_exit SET last_name = SUBSTRING_INDEX(fullname,' ',-1)
UPDATE people_exit SET middle_name = TRIM(SUBSTRING_INDEX(SUBSTRING_INDEX(fullname,last_name,1),' ',-2))
UPDATE people_exit SET middle_name = '' WHERE CHAR_LENGTH(middle_name)>3 
UPDATE people_exit SET first_name = SUBSTRING_INDEX(fullname,concat(middle_name,' ',last_name),1)
UPDATE people_exit SET first_name = middle_name WHERE first_name = ''
UPDATE people_exit SET middle_name = '' WHERE first_name = middle_name

mysql query order by multiple items

SELECT id, user_id, video_name
FROM sa_created_videos
ORDER BY LENGTH(id) ASC, LENGTH(user_id) DESC

HTML colspan in CSS

Another suggestion is using flexbox instead of tables altogether. This is a "modern browser" thing of course, but come on, it's 2016 ;)

At least this might be an alternative solution for those looking for an answer to this nowadays, since the original post was from 2010.

Here's a great guide: https://css-tricks.com/snippets/css/a-guide-to-flexbox/

_x000D_
_x000D_
.table {_x000D_
  border: 1px solid red;_x000D_
  padding: 2px;_x000D_
  max-width: 300px;_x000D_
  display: flex;_x000D_
  flex-flow: row wrap;_x000D_
}_x000D_
.table-cell {_x000D_
  border: 1px solid blue;_x000D_
  flex: 1 30%;_x000D_
}_x000D_
.colspan-3 {_x000D_
  border: 1px solid green;_x000D_
  flex: 1 100%;_x000D_
}
_x000D_
<div class="table">_x000D_
  <div class="table-cell">_x000D_
    row 1 - cell 1_x000D_
  </div>_x000D_
  <div class="table-cell">_x000D_
    row 1 - cell 2_x000D_
  </div>_x000D_
  <div class="table-cell">_x000D_
    row 1 - cell 3_x000D_
  </div>_x000D_
  <div class="table-cell colspan-3">_x000D_
    row 2 - cell 1 (spans 3 columns)_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Fastest way to check if string contains only digits

Very Clever and easy way to detect your string is contains only digits or not is this way:

string s = "12fg";

if(s.All(char.IsDigit))
{
   return true; // contains only digits
}
else
{
   return false; // contains not only digits
}

Using str_replace so that it only acts on the first match?

$str = "Hello there folks!"
$str_ex = explode("there, $str, 2);   //explodes $string just twice
                                      //outputs: array ("Hello ", " folks")
$str_final = implode("", $str_ex);    // glues above array together
                                      // outputs: str("Hello  folks")

There is one more additional space but it didnt matter as it was for backgound script in my case.

WPF TabItem Header Styling

While searching for a way to round tabs, I found Carlo's answer and it did help but I needed a bit more. Here is what I put together, based on his work. This was done with MS Visual Studio 2015.

The Code:

<Window x:Class="MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:MealNinja"
        mc:Ignorable="d"
        Title="Rounded Tabs Example" Height="550" Width="700" WindowStartupLocation="CenterScreen" FontFamily="DokChampa" FontSize="13.333" ResizeMode="CanMinimize" BorderThickness="0">
    <Window.Effect>
        <DropShadowEffect Opacity="0.5"/>
    </Window.Effect>
    <Grid Background="#FF423C3C">
        <TabControl x:Name="tabControl" TabStripPlacement="Left" Margin="6,10,10,10" BorderThickness="3">
            <TabControl.Resources>
                <Style TargetType="{x:Type TabItem}">
                    <Setter Property="Template">
                        <Setter.Value>
                            <ControlTemplate TargetType="{x:Type TabItem}">
                                <Grid>
                                    <Border Name="Border" Background="#FF6E6C67" Margin="2,2,-8,0" BorderBrush="Black" BorderThickness="1,1,1,1" CornerRadius="10">
                                        <ContentPresenter x:Name="ContentSite" ContentSource="Header" VerticalAlignment="Center" HorizontalAlignment="Center" Margin="2,2,12,2" RecognizesAccessKey="True"/>
                                    </Border>
                                    <Rectangle Height="100" Width="10" Margin="0,0,-10,0" Stroke="Black" VerticalAlignment="Bottom" HorizontalAlignment="Right" StrokeThickness="0" Fill="#FFD4D0C8"/>
                                </Grid>
                                <ControlTemplate.Triggers>
                                    <Trigger Property="IsSelected" Value="True">
                                        <Setter Property="FontWeight" Value="Bold" />
                                        <Setter TargetName="ContentSite" Property="Width" Value="30" />
                                        <Setter TargetName="Border" Property="Background" Value="#FFD4D0C8" />
                                    </Trigger>
                                    <Trigger Property="IsEnabled" Value="False">
                                        <Setter TargetName="Border" Property="Background" Value="#FF6E6C67" />
                                    </Trigger>
                                    <Trigger Property="IsMouseOver" Value="true">
                                        <Setter Property="FontWeight" Value="Bold" />
                                    </Trigger>
                                </ControlTemplate.Triggers>
                            </ControlTemplate>
                        </Setter.Value>
                    </Setter>
                    <Setter Property="HeaderTemplate">
                        <Setter.Value>
                            <DataTemplate>
                                <ContentPresenter Content="{TemplateBinding Content}">
                                    <ContentPresenter.LayoutTransform>
                                        <RotateTransform Angle="270" />
                                    </ContentPresenter.LayoutTransform>
                                </ContentPresenter>
                            </DataTemplate>
                        </Setter.Value>
                    </Setter>
                    <Setter Property="Background" Value="#FF6E6C67" />
                    <Setter Property="Height" Value="90" />
                    <Setter Property="Margin" Value="0" />
                    <Setter Property="Padding" Value="0" />
                    <Setter Property="FontFamily" Value="DokChampa" />
                    <Setter Property="FontSize" Value="16" />
                    <Setter Property="VerticalAlignment" Value="Top" />
                    <Setter Property="HorizontalAlignment" Value="Right" />
                    <Setter Property="UseLayoutRounding" Value="False" />
                </Style>
                <Style x:Key="tabGrids">
                    <Setter Property="Grid.Background" Value="#FFE5E5E5" />
                    <Setter Property="Grid.Margin" Value="6,10,10,10" />
                </Style>
            </TabControl.Resources>
            <TabItem Header="Planner">
                <Grid Style="{StaticResource tabGrids}"/>
            </TabItem>
            <TabItem Header="Section 2">
                <Grid Style="{StaticResource tabGrids}"/>
            </TabItem>
            <TabItem Header="Section III">
                <Grid Style="{StaticResource tabGrids}"/>
            </TabItem>
            <TabItem Header="Section 04">
                <Grid Style="{StaticResource tabGrids}"/>
            </TabItem>
            <TabItem Header="Tools">
                <Grid Style="{StaticResource tabGrids}"/>
            </TabItem>
        </TabControl>
    </Grid>
</Window>

Screenshot:

enter image description here

Is string in array?

Linq (for s&g's):

var test = "This is the string I'm looking for";
var found = strArray.Any(x=>x == test);

or, depending on requirements

var found = strArray.Any(
    x=>x.Equals(test, StringComparison.OrdinalIgnoreCase));

<modules runAllManagedModulesForAllRequests="true" /> Meaning

Modules Preconditions:

The IIS core engine uses preconditions to determine when to enable a particular module. Performance reasons, for example, might determine that you only want to execute managed modules for requests that also go to a managed handler. The precondition in the following example (precondition="managedHandler") only enables the forms authentication module for requests that are also handled by a managed handler, such as requests to .aspx or .asmx files:

<add name="FormsAuthentication" type="System.Web.Security.FormsAuthenticationModule" preCondition="managedHandler" />

If you remove the attribute precondition="managedHandler", Forms Authentication also applies to content that is not served by managed handlers, such as .html, .jpg, .doc, but also for classic ASP (.asp) or PHP (.php) extensions. See "How to Take Advantage of IIS Integrated Pipeline" for an example of enabling ASP.NET modules to run for all content.

You can also use a shortcut to enable all managed (ASP.NET) modules to run for all requests in your application, regardless of the "managedHandler" precondition.

To enable all managed modules to run for all requests without configuring each module entry to remove the "managedHandler" precondition, use the runAllManagedModulesForAllRequests property in the <modules> section:

<modules runAllManagedModulesForAllRequests="true" />    

When you use this property, the "managedHandler" precondition has no effect and all managed modules run for all requests.

Copied from IIS Modules Overview: Preconditions

String.Replace ignoring case

I prefer this - "Hello World".ToLower().Replace( "world", "csharp" );

The Use of Multiple JFrames: Good or Bad Practice?

I'm just wondering whether it is good practice to use multiple JFrames?

Bad (bad, bad) practice.

  • User unfriendly: The user sees multiple icons in their task bar when expecting to see only one. Plus the side effects of the coding problems..
  • A nightmare to code and maintain:
    • A modal dialog offers the easy opportunity to focus attention on the content of that dialog - choose/fix/cancel this, then proceed. Multiple frames do not.
    • A dialog (or floating tool-bar) with a parent will come to front when the parent is clicked on - you'd have to implement that in frames if that was the desired behavior.

There are any number of ways of displaying many elements in one GUI, e.g.:

  • CardLayout (short demo.). Good for:
    1. Showing wizard like dialogs.
    2. Displaying list, tree etc. selections for items that have an associated component.
    3. Flipping between no component and visible component.
  • JInternalFrame/JDesktopPane typically used for an MDI.
  • JTabbedPane for groups of components.
  • JSplitPane A way to display two components of which the importance between one or the other (the size) varies according to what the user is doing.
  • JLayeredPane far many well ..layered components.
  • JToolBar typically contains groups of actions or controls. Can be dragged around the GUI, or off it entirely according to user need. As mentioned above, will minimize/restore according to the parent doing so.
  • As items in a JList (simple example below).
  • As nodes in a JTree.
  • Nested layouts.

But if those strategies do not work for a particular use-case, try the following. Establish a single main JFrame, then have JDialog or JOptionPane instances appear for the rest of the free-floating elements, using the frame as the parent for the dialogs.

Many images

In this case where the multiple elements are images, it would be better to use either of the following instead:

  1. A single JLabel (centered in a scroll pane) to display whichever image the user is interested in at that moment. As seen in ImageViewer.
  2. A single row JList. As seen in this answer. The 'single row' part of that only works if they are all the same dimensions. Alternately, if you are prepared to scale the images on the fly, and they are all the same aspect ratio (e.g. 4:3 or 16:9).

Bootstrap - Uncaught TypeError: Cannot read property 'fn' of undefined

I had the same problem. Firefox showed me this error but in chrome everything was OK. then after a google search, i used google cdn for jquery in index.html instead of loading local js file and the problem solved.

No found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations:

I missed to add

@Controller("userBo") into UserBoImpl class.

The solution for this is adding this controller into Impl class.

How do I view Android application specific cache?

Cached files are indeed stored in /data/data/my_app_package/cache

Make sure to store the files using the following method:

String cacheDir = context.getCacheDir();
File imageFile = new File(cacheDir, "image1.jpg");
FileOutputStream out = new FileOutputStream(imageFile);
out.write(imagebuffer, 0, imagebufferlength);

where imagebuffer[] contains image data in byte format and imagebufferlength is the length of the content to be written to the FileOutputStream.

Now, you may look at DDMS File Explorer or do an "adb shell" and cd to /data/data/my_app_package/cache and do an "ls". You will find the image files you have stored through code in this directory.

Moreover, from Android documentation:

If you'd like to cache some data, rather than store it persistently, you should use getCacheDir() to open a File that represents the internal directory where your application should save temporary cache files.

When the device is low on internal storage space, Android may delete these cache files to recover space. However, you should not rely on the system to clean up these files for you. You should always maintain the cache files yourself and stay within a reasonable limit of space consumed, such as 1MB. When the user uninstalls your application, these files are removed.

How to split data into training/testing sets using sample function

require(caTools)

set.seed(101)            #This is used to create same samples everytime

split1=sample.split(data$anycol,SplitRatio=2/3)

train=subset(data,split1==TRUE)

test=subset(data,split1==FALSE)

The sample.split() function will add one extra column 'split1' to dataframe and 2/3 of the rows will have this value as TRUE and others as FALSE.Now the rows where split1 is TRUE will be copied into train and other rows will be copied to test dataframe.

React - how to pass state to another component

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

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

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

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

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

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

How to make div occupy remaining height?

I faced the same challenge myself and found these 2 answers using flex properties.

CSS

.container {
  display: flex;
  flex-direction: column;
}

.dynamic-element{
  flex: 1;
}

Simple calculations for working with lat/lon and km distance?

If you're using Java, Javascript or PHP, then there's a library that will do these calculations exactly, using some amusingly complicated (but still fast) trigonometry:

http://www.jstott.me.uk/jcoord/

Using numpy to build an array of all combinations of two arrays

Pandas merge offers a naive, fast solution to the problem:

# given the lists
x, y, z = [1, 2, 3], [4, 5], [6, 7]

# get dfs with same, constant index 
x = pd.DataFrame({'x': x}, index=np.repeat(0, len(x))
y = pd.DataFrame({'y': y}, index=np.repeat(0, len(y))
z = pd.DataFrame({'z': z}, index=np.repeat(0, len(z))

# get all permutations stored in a new df
df = pd.merge(x, pd.merge(y, z, left_index=True, righ_index=True),
              left_index=True, right_index=True)

Django TemplateDoesNotExist?

Check permissions on templates and appname directories, either with ls -l or try doing an absolute path open() from django.

What's the best way to add a full screen background image in React Native

I've heard about having to use BackgroundImage because in future you are supposed to not be able to nest the Image tag. But I could not get BackgroudImage to properly display my background. What I did was nest my Image inside a View tag and style both the outer View as well as the image. Keys were setting width to null, and setting resizeMode to 'stretch'. Below is my code:

_x000D_
_x000D_
import React, {Component} from 'react';_x000D_
import { View, Text, StyleSheet, Image} from 'react-native';_x000D_
_x000D_
export default class BasicImage extends Component {_x000D_
 constructor(props) {_x000D_
   super(props);_x000D_
_x000D_
   this.state = {};_x000D_
 }_x000D_
_x000D_
 render() {_x000D_
  return (_x000D_
   <View style={styles.container}>_x000D_
       <Image _x000D_
         source={this.props.source}_x000D_
         style={styles.backgroundImage}_x000D_
       />_x000D_
      </View>_x000D_
  )_x000D_
 }_x000D_
}_x000D_
_x000D_
const styles = StyleSheet.create({   _x000D_
  container: {_x000D_
   flex: 1,_x000D_
   width: null,_x000D_
   height: null,_x000D_
   marginBottom: 50_x000D_
  },_x000D_
    text: {_x000D_
      marginLeft: 5,_x000D_
      marginTop: 22,_x000D_
      fontFamily: 'fontawesome',_x000D_
        color: 'black',_x000D_
        fontSize: 25,_x000D_
        backgroundColor: 'rgba(0,0,0,0)',_x000D_
    },_x000D_
  backgroundImage: {_x000D_
   flex: 1,_x000D_
   width: null,_x000D_
   height: null,_x000D_
   resizeMode: 'stretch',_x000D_
  }_x000D_
});
_x000D_
_x000D_
_x000D_

Tomcat 8 is not able to handle get request with '|' in query parameters?

Issue: Tomcat (7.0.88) is throwing below exception which leads to 400 – Bad Request.

java.lang.IllegalArgumentException: Invalid character found in the request target. 
The valid characters are defined in RFC 7230 and RFC 3986.

This issue is occurring most of the tomcat versions from 7.0.88 onwards.

Solution: (Suggested by Apache team):

Tomcat increased their security and no longer allows raw square brackets in the query string. In the request we have [,] (Square brackets) so the request is not processed by the server.

Add relaxedQueryChars attribute under tag under server.xml (%TOMCAT_HOME%/conf):

<Connector port="80" 
           protocol="HTTP/1.1"
           maxThreads="150"
           connectionTimeout="20000"
           redirectPort="443"
           compression="on"
           compressionMinSize="2048"
           noCompressionUserAgents="gozilla, traviata"
           compressableMimeType="text/html,text/xml"
                                     relaxedQueryChars="[,]"
             />

If application needs more special characters that are not supported by tomcat by default, then add those special characters in relaxedQueryChars attribute, comma-separated as above.

"ImportError: no module named 'requests'" after installing with pip

Run in command prompt.

pip list

Check what version you have installed on your system if you have an old version.

Try to uninstall the package...

pip uninstall requests

Try after to install it:

pip install requests

You can also test if pip does not do the job.

easy_install requests

jQuery, get ID of each element in a class using .each?

Try this, replacing .myClassName with the actual name of the class (but keep the period at the beginning).

$('.myClassName').each(function() {
    alert( this.id );
});

So if the class is "test", you'd do $('.test').each(func....

This is the specific form of .each() that iterates over a jQuery object.

The form you were using iterates over any type of collection. So you were essentially iterating over an array of characters t,e,s,t.

Using that form of $.each(), you would need to do it like this:

$.each($('.myClassName'), function() {
    alert( this.id );
});

...which will have the same result as the example above.

ERROR : [Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified

I got a similar error, which was resolved by installing the corresponding MySQL drivers from:

http://www.connectionstrings.com/mysql-connector-odbc-5-2/info-and-download/

and by performing the following steps:

  1. Go to IIS and Application Pools in the left menu.
  2. Select relevant application pool which is assigned to the project.
  3. Click the Set Application Pool Defaults.
  4. In General Tab, set the Enable 32 Bit Application entry to "True".

Reference:

http://www.codeproject.com/Tips/305249/ERROR-IM-Microsoft-ODBC-Driver-Manager-Data-sou

move_uploaded_file gives "failed to open stream: Permission denied" error

If you have Mac OS X, go to the file root or the folder of your website.

Then right-hand click on it, go to get information, go to the very bottom (Sharing & Permissions), open that, change all read-only to read and write. Make sure to open padlock, go to setting icon, and choose Apply to the enclosed items...

Unable to specify the compiler with CMake

Using with FILEPATH option might work:

set(CMAKE_CXX_COMPILER:FILEPATH C:/MinGW/bin/gcc.exe)

'Incomplete final line' warning when trying to read a .csv file into R

I got this problem once when I had a single quote as part of the header. When I removed it (i.e. renamed the respective column header from Jimmy's data to Jimmys data), the function returned no warnings.

How do I find files with a path length greater than 260 characters in Windows?

you can redirect stderr.

more explanation here, but having a command like:

MyCommand >log.txt 2>errors.txt

should grab the data you are looking for.

Also, as a trick, Windows bypasses that limitation if the path is prefixed with \\?\ (msdn)

Another trick if you have a root or destination that starts with a long path, perhaps SUBST will help:

SUBST Q: "C:\Documents and Settings\MyLoginName\My Documents\MyStuffToBeCopied"
Xcopy Q:\ "d:\Where it needs to go" /s /e
SUBST Q: /D

Are there any SHA-256 javascript implementations that are generally considered trustworthy?

No, there's no way to use browser JavaScript to improve password security. I highly recommend you read this article. In your case, the biggest problem is the chicken-egg problem:

What's the "chicken-egg problem" with delivering Javascript cryptography?

If you don't trust the network to deliver a password, or, worse, don't trust the server not to keep user secrets, you can't trust them to deliver security code. The same attacker who was sniffing passwords or reading diaries before you introduce crypto is simply hijacking crypto code after you do.

[...]

Why can't I use TLS/SSL to deliver the Javascript crypto code?

You can. It's harder than it sounds, but you safely transmit Javascript crypto to a browser using SSL. The problem is, having established a secure channel with SSL, you no longer need Javascript cryptography; you have "real" cryptography.

Which leads to this:

The problem with running crypto code in Javascript is that practically any function that the crypto depends on could be overridden silently by any piece of content used to build the hosting page. Crypto security could be undone early in the process (by generating bogus random numbers, or by tampering with constants and parameters used by algorithms), or later (by spiriting key material back to an attacker), or --- in the most likely scenario --- by bypassing the crypto entirely.

There is no reliable way for any piece of Javascript code to verify its execution environment. Javascript crypto code can't ask, "am I really dealing with a random number generator, or with some facsimile of one provided by an attacker?" And it certainly can't assert "nobody is allowed to do anything with this crypto secret except in ways that I, the author, approve of". These are two properties that often are provided in other environments that use crypto, and they're impossible in Javascript.

Basically the problem is this:

  • Your clients don't trust your servers, so they want to add extra security code.
  • That security code is delivered by your servers (the ones they don't trust).

Or alternatively,

  • Your clients don't trust SSL, so they want you use extra security code.
  • That security code is delivered via SSL.

Note: Also, SHA-256 isn't suitable for this, since it's so easy to brute force unsalted non-iterated passwords. If you decide to do this anyway, look for an implementation of bcrypt, scrypt or PBKDF2.

Processing Symbol Files in Xcode

Add SDK version correspond to your iPhone iOS, eg: iOS 10.3

path:

/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport


It's downloading. When it's finished, it's OK. As shown in the figure:

enter image description here

EXEC sp_executesql with multiple parameters

If one need to use the sp_executesql with OUTPUT variables:

EXEC sp_executesql @sql
                  ,N'@p0 INT'
                  ,N'@p1 INT OUTPUT'
                  ,N'@p2 VARCHAR(12) OUTPUT' 
                  ,@p0
                  ,@p1 OUTPUT
                  ,@p2 OUTPUT;

TLS 1.2 not working in cURL

You must use an integer value for the CURLOPT_SSLVERSION value, not a string as listed above

Try this:

curl_setopt ($setuploginurl, CURLOPT_SSLVERSION, 6); //Integer NOT string TLS v1.2

http://php.net/manual/en/function.curl-setopt.php

value should be an integer for the following values of the option parameter: CURLOPT_SSLVERSION

One of

CURL_SSLVERSION_DEFAULT (0)
CURL_SSLVERSION_TLSv1 (1)
CURL_SSLVERSION_SSLv2 (2)
CURL_SSLVERSION_SSLv3 (3)
CURL_SSLVERSION_TLSv1_0 (4)
CURL_SSLVERSION_TLSv1_1 (5)
CURL_SSLVERSION_TLSv1_2 (6).

Nested select statement in SQL Server

You need to alias the subquery.

SELECT name FROM (SELECT name FROM agentinformation) a  

or to be more explicit

SELECT a.name FROM (SELECT name FROM agentinformation) a  

CSS image overlay with color and transparency

If you want to make the reverse of what you showed consider doing this:

.tint:hover:before {
    background: rgba(0,0,250, 0.5);

  }

  .t2:before {
    background: none;
  }

and look at the effect on the 2nd picture.

Is it supposed to look like this?

How to check whether a select box is empty using JQuery/Javascript

Another correct way to get selected value would be using this selector:

$("option[value="0"]:selected")

Best for you!

How can I use external JARs in an Android project?

Turns out I have not looked good enough at my stack trace, the problem is not that the external JAR is not included.

The problem is that Android platform is missing javax.naming.* and many other packages that the external JAR has dependencies too.

Adding external JAR files, and setting Order and Export in Eclipse works as expected with Android projects.

jQuery - Get Width of Element when Not Visible (Display: None)

As has been said before, the clone and attach elsewhere method does not guarantee the same results as styling may be different.

Below is my approach. It travels up the parents looking for the parent responsible for the hiding, then temporarily unhides it to calculate the required width, height, etc.

_x000D_
_x000D_
    var width = parseInt($image.width(), 10);_x000D_
    var height = parseInt($image.height(), 10);_x000D_
_x000D_
    if (width === 0) {_x000D_
_x000D_
        if ($image.css("display") === "none") {_x000D_
_x000D_
            $image.css("display", "block");_x000D_
            width = parseInt($image.width(), 10);_x000D_
            height = parseInt($image.height(), 10);_x000D_
            $image.css("display", "none");_x000D_
        }_x000D_
        else {_x000D_
_x000D_
            $image.parents().each(function () {_x000D_
_x000D_
                var $parent = $(this);_x000D_
                if ($parent.css("display") === "none") {_x000D_
_x000D_
                    $parent.css("display", "block");_x000D_
                    width = parseInt($image.width(), 10);_x000D_
                    height = parseInt($image.height(), 10);_x000D_
                    $parent.css("display", "none");_x000D_
                }_x000D_
            });_x000D_
        }_x000D_
    }
_x000D_
_x000D_
_x000D_

how to extract only the year from the date in sql server 2008?

year(@date)
year(getdate())
year('20120101')

update table
set column = year(date_column)
whre ....

or if you need it in another table

 update t
   set column = year(t1.date_column)
     from table_source t1
     join table_target t on (join condition)
    where ....

Default value for field in Django model

You can also use a callable in the default field, such as:

b = models.CharField(max_length=7, default=foo)

And then define the callable:

def foo():
    return 'bar'

Can I fade in a background image (CSS: background-image) with jQuery?

This is what worked for my, and its pure css


css

html {
    padding: 0;
    margin: 0;
    width: 100%;
    height: 100%;
  }

  body {
    padding: 0;
    margin: 0;
    width: 100%;
    height: 100%;
  }

  #bg {
    width: 100%;
    height: 100%;
    background: url('/image.jpg/') no-repeat center center fixed;

    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;

    -webkit-animation: myfirst 5s ; /* Chrome, Safari, Opera */
    animation: myfirst 5s ;
  }

  /* Chrome, Safari, Opera */
  @-webkit-keyframes myfirst {
    from {opacity: 0.2;}
    to {opacity: 1;}
  }

  /* Standard syntax */
  @keyframes myfirst {
    from {opacity: 0.2;}
    to {opacity: 1;}
  }

html

<!DOCTYPE html>
<html>
<head>
    <title></title>
</head>
<body>
  <div id="bg">
    <!-- content here -->
  </div> <!-- end bg -->
</body>
</html>

Implement specialization in ER diagram

So I assume your permissions table has a foreign key reference to admin_accounts table. If so because of referential integrity you will only be able to add permissions for account ids exsiting in the admin accounts table. Which also means that you wont be able to enter a user_account_id [assuming there are no duplicates!]

MD5 hashing in Android

MD5 is a bit old, SHA-1 is a better algorithm, there is a example here.

(Also as they note in that post, Java handles this on it's own, no Android specific code.)

SQL - The conversion of a varchar data type to a datetime data type resulted in an out-of-range value

I ran into this issue due to a silly mistake. Make sure the date actually exists!

For example:

September 31, 2015 does not exist.

EXEC dbo.SearchByDateRange @Start = '20150901' , @End = '20150931'

So this fails with the message:

Error converting data type varchar to datetime.

To fix it, input a valid date:

EXEC dbo.SearchByDateRange @Start = '20150901' , @End = '20150930'

And it executes just fine.

What are the options for (keyup) in Angular2?

you can add keyup event like this

template: `
  <input (keyup)="onKey($event)">
  <p>{{values}}</p>
`

in Component, code some like below

export class KeyUpComponent_v1 {
  values = '';

  onKey(event:any) { // without type info
    this.values += event.target.value + ' | ';
  }
}