SyntaxFix

Programs & Examples On #Goroutine

A goroutine is a lightweight thread of execution that is managed by the Go language runtime.

How to asynchronously call a method in Java

You can use AsyncFunc from Cactoos:

boolean matches = new AsyncFunc(
  x -> x.matches("something")
).apply("The text").get();

It will be executed at the background and the result will be available in get() as a Future.

How to stop a goroutine

I know this answer has already been accepted, but I thought I'd throw my 2cents in. I like to use the tomb package. It's basically a suped up quit channel, but it does nice things like pass back any errors as well. The routine under control still has the responsibility of checking for remote kill signals. Afaik it's not possible to get an "id" of a goroutine and kill it if it's misbehaving (ie: stuck in an infinite loop).

Here's a simple example which I tested:

package main

import (
  "launchpad.net/tomb"
  "time"
  "fmt"
)

type Proc struct {
  Tomb tomb.Tomb
}

func (proc *Proc) Exec() {
  defer proc.Tomb.Done() // Must call only once
  for {
    select {
    case <-proc.Tomb.Dying():
      return
    default:
      time.Sleep(300 * time.Millisecond)
      fmt.Println("Loop the loop")
    }
  }
}

func main() {
  proc := &Proc{}
  go proc.Exec()
  time.Sleep(1 * time.Second)
  proc.Tomb.Kill(fmt.Errorf("Death from above"))
  err := proc.Tomb.Wait() // Will return the error that killed the proc
  fmt.Println(err)
}

The output should look like:

# Loop the loop
# Loop the loop
# Loop the loop
# Loop the loop
# Death from above

Add column with number of days between dates in DataFrame pandas

Assuming these were datetime columns (if they're not apply to_datetime) you can just subtract them:

df['A'] = pd.to_datetime(df['A'])
df['B'] = pd.to_datetime(df['B'])

In [11]: df.dtypes  # if already datetime64 you don't need to use to_datetime
Out[11]:
A    datetime64[ns]
B    datetime64[ns]
dtype: object

In [12]: df['A'] - df['B']
Out[12]:
one   -58 days
two   -26 days
dtype: timedelta64[ns]

In [13]: df['C'] = df['A'] - df['B']

In [14]: df
Out[14]:
             A          B        C
one 2014-01-01 2014-02-28 -58 days
two 2014-02-03 2014-03-01 -26 days

Note: ensure you're using a new of pandas (e.g. 0.13.1), this may not work in older versions.

Is there a better way to run a command N times in bash?

xargs and seq will help

function __run_times { seq 1 $1| { shift; xargs -i -- "$@"; } }

the view :

abon@abon:~$ __run_times 3  echo hello world
hello world
hello world
hello world

Create session factory in Hibernate 4

 
Configuration hibConfiguration = new Configuration()
            .addResource("wp4core/hibernate/config/table.hbm.xml")
            .configure();       

serviceRegistry = new ServiceRegistryBuilder()
            .applySettings(hibConfiguration.getProperties())
            .buildServiceRegistry();

sessionFactory = hibConfiguration.buildSessionFactory(serviceRegistry);
session = sessionFactory.withOptions().openSession();

Create an Array of Arraylists

You can do this :

//Create an Array of type ArrayList

`ArrayList<Integer>[] a = new ArrayList[n];`

//For each element in array make an ArrayList

for(int i=0; i<n; i++){ 
    a[i] = new ArrayList<Integer>();
}

Is there a way to override class variables in Java?

If you are going to override it I don't see a valid reason to keep this static. I would suggest the use of abstraction (see example code). : 

     public interface Person {
        public abstract String getName();
       //this will be different for each person, so no need to make it concrete
        public abstract void setName(String name);
    }

Now we can add the Dad:

public class Dad implements Person {

    private String name;

    public Dad(String name) {
        setName(name);
    }

    @Override
    public final String getName() {
    return name;
    }

    @Override
    public final void setName(String name) {
        this.name = name;
    }
}

the son:

public class Son implements Person {

    private String name;

    public Son(String name) {
        setName(name);
    }

    @Override
    public final String getName() {
        return name;
    }

    @Override
    public final void setName(String name) {
        this.name = name;
    }
}

and Dad met a nice lady:

public class StepMom implements Person {

    private String name;

    public StepMom(String name) {
        setName(name);
    }

    @Override
    public final String getName() {
        return name;
    }

    @Override
    public final void setName(String name) {
        this.name = name;
    }
}

Looks like we have a family, lets tell the world their names:

public class ConsoleGUI {

    public static void main(String[] args) {
        List<Person> family = new ArrayList<Person>();
        family.add(new Son("Tommy"));
        family.add(new StepMom("Nancy"));
        family.add(new Dad("Dad"));
        for (Person person : family) {
            //using the getName vs printName lets the caller, in this case the
            //ConsoleGUI determine versus being forced to output through the console. 
            System.out.print(person.getName() + " ");
            System.err.print(person.getName() + " ");
            JOptionPane.showMessageDialog(null, person.getName());
    }
}

}

System.out Output : Tommy Nancy Dad
System.err is the same as above(just has red font)
JOption Output:
Tommy then
Nancy then
Dad

Exclude property from type

Omit

single property

type T1 = Omit<XYZ, "z"> // { x: number; y: number; }

multiple properties

type T2 = Omit<XYZ, "y" | "z"> // { x: number; }

properties conditionally

e.g. all string types: 
type Keys_StringExcluded<T> = 
  { [K in keyof T]: T[K] extends string ? never : K }[keyof T]

type XYZ = { x: number; y: string; z: number; }
type T3a = Pick<XYZ, Keys_StringExcluded<XYZ>> // { x: number; z: number; }
Shorter version with TS 4.1 key remapping / as clause in mapped types (PR): 
type T3b = { [K in keyof XYZ as XYZ[K] extends string ? never : K]: XYZ[K] } 
// { x: number; z: number; }

properties by string pattern

e.g. exclude getters (props with 'get' string prefixes) 
type OmitGet<T> = {[K in keyof T as K extends `get${infer _}` ? never : K]: T[K]}

type XYZ2 = { getA: number; b: string; getC: boolean; }
type T4 = OmitGet<XYZ2> //  { b: string; }

Note: Above template literal types are supported with TS 4.1.
Note 2: You can also write get${string} instead of get${infer _} here.

Pick, Omit and other utility types

How to Pick and rename certain keys using Typescript? (rename instead of exclude)

Playground

How to find numbers from a string?

Expanding on brettdj's answer, in order to parse disjoint embedded digits into separate numbers:

Sub TestNumList()
    Dim NumList As Variant  'Array

    NumList = GetNums("34d1fgd43g1 dg5d999gdg2076")

    Dim i As Integer
    For i = LBound(NumList) To UBound(NumList)
        MsgBox i + 1 & ": " & NumList(i)
    Next i
End Sub

Function GetNums(ByVal strIn As String) As Variant  'Array of numeric strings
    Dim RegExpObj As Object
    Dim NumStr As String

    Set RegExpObj = CreateObject("vbscript.regexp")
    With RegExpObj
        .Global = True
        .Pattern = "[^\d]+"
        NumStr = .Replace(strIn, " ")
    End With

    GetNums = Split(Trim(NumStr), " ")
End Function

Check if String contains only letters

Check this,i guess this is help you because it's work in my project so once you check this code

if(! Pattern.matches(".*[a-zA-Z]+.*[a-zA-Z]", str1))
 {
   String not contain only character;
 }
else 
{
  String contain only character;
}

Why would a "java.net.ConnectException: Connection timed out" exception occur when URL is up?

I'd recommend raising the connection timeout time before getting the output stream, like so:

urlConnection.setConnectTimeout(1000);

Where 1000 is in milliseconds (1000 milliseconds = 1 second).

HTML anchor link - href and onclick both?

Just return true instead?

The return value from the onClick code is what determines whether the link's inherent clicked action is processed or not - returning false means that it isn't processed, but if you return true then the browser will proceed to process it after your function returns and go to the proper anchor.

Rails: How can I rename a database column in a Ruby on Rails migration?

From API:

rename_column(table_name, column_name, new_column_name)

It renames a column but keeps the type and content remains same.

PHP removing a character in a string

 
$str = preg_replace('/\?\//', '?', $str);

Edit: See CMS' answer. It's late, I should know better.

Easiest way to copy a table from one database to another?

With MySQL Workbench you can use Data Export to dump just the table to a local SQL file (Data Only, Structure Only or Structure and Data) and then Data Import to load it into the other DB.

You can have multiple connections (different hosts, databases, users) open at the same time.

How to add items into a numpy array

np.insert can also be used for the purpose

import numpy as np
a = np.array([[1, 3, 4],
              [1, 2, 3],
              [1, 2, 1]])
x = 5
index = 3 # the position for x to be inserted before
np.insert(a, index, x, axis=1)

array([[1, 3, 4, 5],
       [1, 2, 3, 5],
       [1, 2, 1, 5]])

index can also be a list/tuple

>>> index = [1, 1, 3] # equivalently (1, 1, 3)
>>> np.insert(a, index, x, axis=1)
array([[1, 5, 5, 3, 4, 5],
       [1, 5, 5, 2, 3, 5],
       [1, 5, 5, 2, 1, 5]])

or a slice

>>> index = slice(0, 3)
>>> np.insert(a, index, x, axis=1)
array([[5, 1, 5, 3, 5, 4],
       [5, 1, 5, 2, 5, 3],
       [5, 1, 5, 2, 5, 1]])

Can not deserialize instance of java.lang.String out of START_ARRAY token

The error is:

Can not deserialize instance of java.lang.String out of START_ARRAY token at [Source: line: 1, column: 1095] (through reference chain: JsonGen["platforms"])

In JSON, platforms look like this:

"platforms": [
    {
        "platform": "iphone"
    },
    {
        "platform": "ipad"
    },
    {
        "platform": "android_phone"
    },
    {
        "platform": "android_tablet"
    }
]

So try change your pojo to something like this:

private List platforms;

public List getPlatforms(){
    return this.platforms;
}

public void setPlatforms(List platforms){
    this.platforms = platforms;
}

EDIT: you will need change mobile_networks too. Will look like this:

private List mobile_networks;

public List getMobile_networks() {
    return mobile_networks;
}

public void setMobile_networks(List mobile_networks) {
    this.mobile_networks = mobile_networks;
}

The opposite of Intersect()

As stated, if you want to get 4 as the result, you can do like this:

var nonintersect = array2.Except(array1);

If you want the real non-intersection (also both 1 and 4), then this should do the trick:

var nonintersect = array1.Except(array2).Union( array2.Except(array1));

This will not be the most performant solution, but for small lists it should work just fine.

Redirecting to another page in ASP.NET MVC using JavaScript/jQuery

 
// in the HTML code I used some razor
@Html.Hidden("RedirectTo", Url.Action("Action", "Controller"));

// now down in the script I do this
<script type="text/javascript">

var url = $("#RedirectTo").val();

$(document).ready(function () {
    $.ajax({
        dataType: 'json',
        type: 'POST',
        url: '/Controller/Action',
        success: function (result) {
            if (result.UserFriendlyErrMsg === 'Some Message') {
                // display a prompt
                alert("Message: " + result.UserFriendlyErrMsg);
                // redirect us to the new page
                location.href = url;
            }
            $('#friendlyMsg').html(result.UserFriendlyErrMsg);
        }
    });
</script>

How do I open a URL from C++?

Here's an example in windows code using winsock.

#include <winsock2.h>
#include <windows.h>
#include <iostream>
#include <string>
#include <locale>
#pragma comment(lib,"ws2_32.lib")
using namespace std;

string website_HTML;
locale local;


void get_Website(char *url );

int main ()
{
    //open website
    get_Website("www.google.com" );

    //format website HTML
    for (size_t i=0; i<website_HTML.length(); ++i) 
        website_HTML[i]= tolower(website_HTML[i],local);

    //display HTML
    cout <<website_HTML;

    cout<<"\n\n";



    return 0;
}



//***************************
void get_Website(char *url )
{
    WSADATA wsaData;
    SOCKET Socket;
    SOCKADDR_IN SockAddr;


    int lineCount=0;
    int rowCount=0;

    struct hostent *host;
    char *get_http= new char[256];

        memset(get_http,' ', sizeof(get_http) );
        strcpy(get_http,"GET / HTTP/1.1\r\nHost: ");
        strcat(get_http,url);
        strcat(get_http,"\r\nConnection: close\r\n\r\n");

        if (WSAStartup(MAKEWORD(2,2), &wsaData) != 0) 
        {
            cout << "WSAStartup failed.\n";
            system("pause");
            //return 1;
        }

        Socket=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
        host = gethostbyname(url);

        SockAddr.sin_port=htons(80);
        SockAddr.sin_family=AF_INET;
        SockAddr.sin_addr.s_addr = *((unsigned long*)host->h_addr);

        cout << "Connecting to "<< url<<" ...\n";

        if(connect(Socket,(SOCKADDR*)(&SockAddr),sizeof(SockAddr)) != 0)
        {
            cout << "Could not connect";
            system("pause");
            //return 1;
        }

        cout << "Connected.\n";     
        send(Socket,get_http, strlen(get_http),0 );

        char buffer[10000];

        int nDataLength;
            while ((nDataLength = recv(Socket,buffer,10000,0)) > 0)
            {       
                int i = 0;

                while (buffer[i] >= 32 || buffer[i] == '\n' || buffer[i] == '\r') 
                {                    
                    website_HTML+=buffer[i];                     
                    i += 1;
                }               
            }
        closesocket(Socket);
        WSACleanup();

            delete[] get_http;
}

Java String.split() Regex

Can you invert your regex so split by the non operation characters?

String ops[] = string.split("[a-z]")
// ops == [+, -, *, /, <, >, >=, <=, == ]

This obviously doesn't return the variables in the array. Maybe you can interleave two splits (one by the operators, one by the variables)

Setting equal heights for div's with jQuery

Important improvement! (I added $(this).height('auto'); before measuring height - we should reset it to auto. Then we can use this function on resize)

function equalheight () {
            $('.cont_for_height').each(function(){  

                var highestBox = 0;
                $('.column_height', this).each(function(){

                    var htmlString = $( this ).html()

                    ;


                $(this).height('auto');

                    if($(this).height() > highestBox) 
                       highestBox = $(this).height(); 
                });  

                $('.column_height',this).height(highestBox);

        });  

        }

htmlentities() vs. htmlspecialchars()

 
**HTML Character Entity Reference Chart at W3.org**

https://dev.w3.org/html5/html-author/charref

&Tab;
&NewLine;
!
&excl;
"
&quot; &QUOT;
#
&num;
$
&dollar;
%
&percnt;
&
&amp; &AMP;
'
&apos;
(
&lpar;
)
&rpar;
*
&ast; &midast;
+
&plus;
,
&comma;
.
&period;
/
&sol;
:
&colon;
;
&semi;
<
&lt; &LT;
=
&equals;
>
&gt; &GT;
?
&quest;
@
&commat;
[
&lsqb; &lbrack;
\
&bsol;
]
&rsqb; &rbrack;
^
&Hat;
_
&lowbar;
`
&grave; &DiacriticalGrave;
{
&lcub; &lbrace;
|
&verbar; &vert; &VerticalLine;
}
&rcub; &rbrace;

&nbsp; &NonBreakingSpace;
¡
&iexcl;
¢
&cent;
£
&pound;
¤
&curren;
¥
&yen;
¦
&brvbar;
§
&sect;
¨
&Dot; &die; &DoubleDot; &uml;
©
&copy; &COPY;
ª
&ordf;
«
&laquo;
¬
&not;
&shy;
®
&reg; &circledR; &REG;
¯
&macr; &OverBar; &strns;
°
&deg;
±
&plusmn; &pm; &PlusMinus;
²
&sup2;
³
&sup3;
´
&acute; &DiacriticalAcute;
µ
&micro;
¶
&para;
·
&middot; &centerdot; &CenterDot;
¸
&cedil; &Cedilla;
¹
&sup1;
º
&ordm;
»
&raquo;
¼
&frac14;
½
&frac12; &half;
¾
&frac34;
¿
&iquest;
À
&Agrave;
Á
&Aacute;
Â
&Acirc;
Ã
&Atilde;
Ä
&Auml;
Å
&Aring;
Æ
&AElig;
Ç
&Ccedil;
È
&Egrave;
É
&Eacute;
Ê
&Ecirc;
Ë
&Euml;
Ì
&Igrave;
Í
&Iacute;
Î
&Icirc;
Ï
&Iuml;
Ð
&ETH;
Ñ
&Ntilde;
Ò
&Ograve;
Ó
&Oacute;
Ô
&Ocirc;
Õ
&Otilde;
Ö
&Ouml;
×
&times;
Ø
&Oslash;
Ù
&Ugrave;
Ú
&Uacute;
Û
&Ucirc;
Ü
&Uuml;
Ý
&Yacute;
Þ
&THORN;
ß
&szlig;
à
&agrave;
á
&aacute;
â
&acirc;
ã
&atilde;
ä
&auml;
å
&aring;
æ
&aelig;
ç
&ccedil;
è
&egrave;
é
&eacute;
ê
&ecirc;
ë
&euml;
ì
&igrave;
í
&iacute;
î
&icirc;
ï
&iuml;
ð
&eth;
ñ
&ntilde;
ò
&ograve;
ó
&oacute;
ô
&ocirc;
õ
&otilde;
ö
&ouml;
÷
&divide; &div;
ø
&oslash;
ù
&ugrave;
ú
&uacute;
û
&ucirc;
ü
&uuml;
ý
&yacute;
þ
&thorn;
ÿ
&yuml;
A
&Amacr;
a
&amacr;
A
&Abreve;
a
&abreve;
A
&Aogon;
a
&aogon;
C
&Cacute;
c
&cacute;
C
&Ccirc;
c
&ccirc;
C
&Cdot;
c
&cdot;
C
&Ccaron;
c
&ccaron;
D
&Dcaron;
d
&dcaron;
Ð
&Dstrok;
d
&dstrok;
E
&Emacr;
e
&emacr;
E
&Edot;
e
&edot;
E
&Eogon;
e
&eogon;
E
&Ecaron;
e
&ecaron;
G
&Gcirc;
g
&gcirc;
G
&Gbreve;
g
&gbreve;
G
&Gdot;
g
&gdot;
G
&Gcedil;
H
&Hcirc;
h
&hcirc;
H
&Hstrok;
h
&hstrok;
I
&Itilde;
i
&itilde;
I
&Imacr;
i
&imacr;
I
&Iogon;
i
&iogon;
I
&Idot;
i
&imath; &inodot;
?
&IJlig;
?
&ijlig;
J
&Jcirc;
j
&jcirc;
K
&Kcedil;
k
&kcedil;
?
&kgreen;
L
&Lacute;
l
&lacute;
L
&Lcedil;
l
&lcedil;
L
&Lcaron;
l
&lcaron;
?
&Lmidot;
?
&lmidot;
L
&Lstrok;
l
&lstrok;
N
&Nacute;
n
&nacute;
N
&Ncedil;
n
&ncedil;
N
&Ncaron;
n
&ncaron;
?
&napos;
?
&ENG;
?
&eng;
O
&Omacr;
o
&omacr;
O
&Odblac;
o
&odblac;
Œ
&OElig;
œ
&oelig;
R
&Racute;
r
&racute;
R
&Rcedil;
r
&rcedil;
R
&Rcaron;
r
&rcaron;
S
&Sacute;
s
&sacute;
S
&Scirc;
s
&scirc;
S
&Scedil;
s
&scedil;
Š
&Scaron;
š
&scaron;
T
&Tcedil;
t
&tcedil;
T
&Tcaron;
t
&tcaron;
T
&Tstrok;
t
&tstrok;
U
&Utilde;
u
&utilde;
U
&Umacr;
u
&umacr;
U
&Ubreve;
u
&ubreve;
U
&Uring;
u
&uring;
U
&Udblac;
u
&udblac;
U
&Uogon;
u
&uogon;
W
&Wcirc;
w
&wcirc;
Y
&Ycirc;
y
&ycirc;
Ÿ
&Yuml;
Z
&Zacute;
z
&zacute;
Z
&Zdot;
z
&zdot;
Ž
&Zcaron;
ž
&zcaron;
ƒ
&fnof;
?
&imped;
?
&gacute;
?
&jmath;
ˆ
&circ;
?
&caron; &Hacek;
?
&breve; &Breve;
?
&dot; &DiacriticalDot;
°
&ring;
?
&ogon;
˜
&tilde; &DiacriticalTilde;
?
&dblac; &DiacriticalDoubleAcute;
?
&DownBreve;
_
&UnderBar;
?
&Alpha;
?
&Beta;
G
&Gamma;
?
&Delta;
?
&Epsilon;
?
&Zeta;
?
&Eta;
T
&Theta;
?
&Iota;
?
&Kappa;
?
&Lambda;
?
&Mu;
?
&Nu;
?
&Xi;
?
&Omicron;
?
&Pi;
?
&Rho;
S
&Sigma;
?
&Tau;
?
&Upsilon;
F
&Phi;
?
&Chi;
?
&Psi;
O
&Omega;
a
&alpha;
ß
&beta;
?
&gamma;
d
&delta;
e
&epsiv; &varepsilon; &epsilon;
?
&zeta;
?
&eta;
?
&theta;
?
&iota;
?
&kappa;
?
&lambda;
µ
&mu;
?
&nu;
?
&xi;
?
&omicron;
p
&pi;
?
&rho;
?
&sigmav; &varsigma; &sigmaf;
s
&sigma;
t
&tau;
?
&upsi; &upsilon;
f
&phi; &phiv; &varphi;
?
&chi;
?
&psi;
?
&omega;
?
&thetav; &vartheta; &thetasym;
?
&Upsi; &upsih;
?
&straightphi;
?
&piv; &varpi;
?
&Gammad;
?
&gammad; &digamma;
?
&kappav; &varkappa;
?
&rhov; &varrho;
?
&epsi; &straightepsilon;
?
&bepsi; &backepsilon;
?
&IOcy;
?
&DJcy;
?
&GJcy;
?
&Jukcy;
?
&DScy;
?
&Iukcy;
?
&YIcy;
?
&Jsercy;
?
&LJcy;
?
&NJcy;
?
&TSHcy;
?
&KJcy;
?
&Ubrcy;
?
&DZcy;
?
&Acy;
?
&Bcy;
?
&Vcy;
?
&Gcy;
?
&Dcy;
?
&IEcy;
?
&ZHcy;
?
&Zcy;
?
&Icy;
?
&Jcy;
?
&Kcy;
?
&Lcy;
?
&Mcy;
?
&Ncy;
?
&Ocy;
?
&Pcy;
?
&Rcy;
?
&Scy;
?
&Tcy;
?
&Ucy;
?
&Fcy;
?
&KHcy;
?
&TScy;
?
&CHcy;
?
&SHcy;
?
&SHCHcy;
?
&HARDcy;
?
&Ycy;
?
&SOFTcy;
?
&Ecy;
?
&YUcy;
?
&YAcy;
?
&acy;
?
&bcy;
?
&vcy;
?
&gcy;
?
&dcy;
?
&iecy;
?
&zhcy;
?
&zcy;
?
&icy;
?
&jcy;
?
&kcy;
?
&lcy;
?
&mcy;
?
&ncy;
?
&ocy;
?
&pcy;
?
&rcy;
?
&scy;
?
&tcy;
?
&ucy;
?
&fcy;
?
&khcy;
?
&tscy;
?
&chcy;
?
&shcy;
?
&shchcy;
?
&hardcy;
?
&ycy;
?
&softcy;
?
&ecy;
?
&yucy;
?
&yacy;
?
&iocy;
?
&djcy;
?
&gjcy;
?
&jukcy;
?
&dscy;
?
&iukcy;
?
&yicy;
?
&jsercy;
?
&ljcy;
?
&njcy;
?
&tshcy;
?
&kjcy;
?
&ubrcy;
?
&dzcy;
 
&ensp;
 
&emsp;
 
&emsp13;
 
&emsp14;
 
&numsp;
 
&puncsp;
 
&thinsp; &ThinSpace;
 
&hairsp; &VeryThinSpace;
?
&ZeroWidthSpace; &NegativeVeryThinSpace; &NegativeThinSpace; &NegativeMediumSpace; &NegativeThickSpace;
?
&zwnj;
?
&zwj;
?
&lrm;
?
&rlm;
-
&hyphen; &dash;
–
&ndash;
—
&mdash;
-
&horbar;
?
&Verbar; &Vert;
‘
&lsquo; &OpenCurlyQuote;
’
&rsquo; &rsquor; &CloseCurlyQuote;
‚
&lsquor; &sbquo;
“
&ldquo; &OpenCurlyDoubleQuote;
”
&rdquo; &rdquor; &CloseCurlyDoubleQuote;
„
&ldquor; &bdquo;
†
&dagger;
‡
&Dagger; &ddagger;
•
&bull; &bullet;
?
&nldr;
…
&hellip; &mldr;
‰
&permil;
?
&pertenk;
'
&prime;
"
&Prime;
?
&tprime;
`
&bprime; &backprime;
‹
&lsaquo;
›
&rsaquo;
?
&oline;
?
&caret;
?
&hybull;
/
&frasl;
?
&bsemi;
?
&qprime;
?
&MediumSpace;
?
&NoBreak;
?
&ApplyFunction; &af;
?
&InvisibleTimes; &it;
?
&InvisibleComma; &ic;
€
&euro;
?
&tdot; &TripleDot;
?
&DotDot;
C
&Copf; &complexes;
?
&incare;
g
&gscr;
H
&hamilt; &HilbertSpace; &Hscr;
H
&Hfr; &Poincareplane;
H
&quaternions; &Hopf;
h
&planckh;
?
&planck; &hbar; &plankv; &hslash;
I
&Iscr; &imagline;
I
&image; &Im; &imagpart; &Ifr;
L
&Lscr; &lagran; &Laplacetrf;
l
&ell;
N
&Nopf; &naturals;
?
&numero;
?
&copysr;
P
&weierp; &wp;
P
&Popf; &primes;
Q
&rationals; &Qopf;
R
&Rscr; &realine;
R
&real; &Re; &realpart; &Rfr;
R
&reals; &Ropf;
?
&rx;
™
&trade; &TRADE;
Z
&integers; &Zopf;
?
&ohm;
?
&mho;
Z
&Zfr; &zeetrf;
?
&iiota;
Å
&angst;
B
&bernou; &Bernoullis; &Bscr;
C
&Cfr; &Cayleys;
e
&escr;
E
&Escr; &expectation;
F
&Fscr; &Fouriertrf;
M
&phmmat; &Mellintrf; &Mscr;
o
&order; &orderof; &oscr;
?
&alefsym; &aleph;
?
&beth;
?
&gimel;
?
&daleth;
?
&CapitalDifferentialD; &DD;
?
&DifferentialD; &dd;
?
&ExponentialE; &exponentiale; &ee;
?
&ImaginaryI; &ii;
?
&frac13;
?
&frac23;
?
&frac15;
?
&frac25;
?
&frac35;
?
&frac45;
?
&frac16;
?
&frac56;
?
&frac18;
?
&frac38;
?
&frac58;
?
&frac78;
?
&larr; &leftarrow; &LeftArrow; &slarr; &ShortLeftArrow;
?
&uarr; &uparrow; &UpArrow; &ShortUpArrow;
?
&rarr; &rightarrow; &RightArrow; &srarr; &ShortRightArrow;
?
&darr; &downarrow; &DownArrow; &ShortDownArrow;
?
&harr; &leftrightarrow; &LeftRightArrow;
?
&varr; &updownarrow; &UpDownArrow;
?
&nwarr; &UpperLeftArrow; &nwarrow;
?
&nearr; &UpperRightArrow; &nearrow;
?
&searr; &searrow; &LowerRightArrow;
?
&swarr; &swarrow; &LowerLeftArrow;
?
&nlarr; &nleftarrow;
?
&nrarr; &nrightarrow;
?
&rarrw; &rightsquigarrow;
?
&Larr; &twoheadleftarrow;
?
&Uarr;
?
&Rarr; &twoheadrightarrow;
?
&Darr;
?
&larrtl; &leftarrowtail;
?
&rarrtl; &rightarrowtail;
?
&LeftTeeArrow; &mapstoleft;
?
&UpTeeArrow; &mapstoup;
?
&map; &RightTeeArrow; &mapsto;
?
&DownTeeArrow; &mapstodown;
?
&larrhk; &hookleftarrow;
?
&rarrhk; &hookrightarrow;
?
&larrlp; &looparrowleft;
?
&rarrlp; &looparrowright;
?
&harrw; &leftrightsquigarrow;
?
&nharr; &nleftrightarrow;
?
&lsh; &Lsh;
?
&rsh; &Rsh;
?
&ldsh;
?
&rdsh;
?
&crarr;
?
&cularr; &curvearrowleft;
?
&curarr; &curvearrowright;
?
&olarr; &circlearrowleft;
?
&orarr; &circlearrowright;
?
&lharu; &LeftVector; &leftharpoonup;
?
&lhard; &leftharpoondown; &DownLeftVector;
?
&uharr; &upharpoonright; &RightUpVector;
?
&uharl; &upharpoonleft; &LeftUpVector;
?
&rharu; &RightVector; &rightharpoonup;
?
&rhard; &rightharpoondown; &DownRightVector;
?
&dharr; &RightDownVector; &downharpoonright;
?
&dharl; &LeftDownVector; &downharpoonleft;
?
&rlarr; &rightleftarrows; &RightArrowLeftArrow;
?
&udarr; &UpArrowDownArrow;
?
&lrarr; &leftrightarrows; &LeftArrowRightArrow;
?
&llarr; &leftleftarrows;
?
&uuarr; &upuparrows;
?
&rrarr; &rightrightarrows;
?
&ddarr; &downdownarrows;
?
&lrhar; &ReverseEquilibrium; &leftrightharpoons;
?
&rlhar; &rightleftharpoons; &Equilibrium;
?
&nlArr; &nLeftarrow;
?
&nhArr; &nLeftrightarrow;
?
&nrArr; &nRightarrow;
?
&lArr; &Leftarrow; &DoubleLeftArrow;
?
&uArr; &Uparrow; &DoubleUpArrow;
?
&rArr; &Rightarrow; &Implies; &DoubleRightArrow;
?
&dArr; &Downarrow; &DoubleDownArrow;
?
&hArr; &Leftrightarrow; &DoubleLeftRightArrow; &iff;
?
&vArr; &Updownarrow; &DoubleUpDownArrow;
?
&nwArr;
?
&neArr;
?
&seArr;
?
&swArr;
?
&lAarr; &Lleftarrow;
?
&rAarr; &Rrightarrow;
?
&zigrarr;
?
&larrb; &LeftArrowBar;
?
&rarrb; &RightArrowBar;
?
&duarr; &DownArrowUpArrow;
?
&loarr;
?
&roarr;
?
&hoarr;
?
&forall; &ForAll;
?
&comp; &complement;
?
&part; &PartialD;
?
&exist; &Exists;
?
&nexist; &NotExists; &nexists;
Ø
&empty; &emptyset; &emptyv; &varnothing;
?
&nabla; &Del;
?
&isin; &isinv; &Element; &in;
?
&notin; &NotElement; &notinva;
?
&niv; &ReverseElement; &ni; &SuchThat;
?
&notni; &notniva; &NotReverseElement;
?
&prod; &Product;
?
&coprod; &Coproduct;
?
&sum; &Sum;
-
&minus;
±
&mnplus; &mp; &MinusPlus;
?
&plusdo; &dotplus;
\
&setmn; &setminus; &Backslash; &ssetmn; &smallsetminus;
*
&lowast;
°
&compfn; &SmallCircle;
v
&radic; &Sqrt;
?
&prop; &propto; &Proportional; &vprop; &varpropto;
8
&infin;
?
&angrt;
?
&ang; &angle;
?
&angmsd; &measuredangle;
?
&angsph;
|
&mid; &VerticalBar; &smid; &shortmid;
?
&nmid; &NotVerticalBar; &nsmid; &nshortmid;
?
&par; &parallel; &DoubleVerticalBar; &spar; &shortparallel;
?
&npar; &nparallel; &NotDoubleVerticalBar; &nspar; &nshortparallel;
?
&and; &wedge;
?
&or; &vee;
n
&cap;
?
&cup;
?
&int; &Integral;
?
&Int;
?
&tint; &iiint;
?
&conint; &oint; &ContourIntegral;
?
&Conint; &DoubleContourIntegral;
?
&Cconint;
?
&cwint;
?
&cwconint; &ClockwiseContourIntegral;
?
&awconint; &CounterClockwiseContourIntegral;
?
&there4; &therefore; &Therefore;
?
&becaus; &because; &Because;
:
&ratio;
?
&Colon; &Proportion;
?
&minusd; &dotminus;
?
&mDDot;
?
&homtht;
~
&sim; &Tilde; &thksim; &thicksim;
?
&bsim; &backsim;
?
&ac; &mstpos;
?
&acd;
?
&wreath; &VerticalTilde; &wr;
?
&nsim; &NotTilde;
?
&esim; &EqualTilde; &eqsim;
?
&sime; &TildeEqual; &simeq;
?
&nsime; &nsimeq; &NotTildeEqual;
?
&cong; &TildeFullEqual;
?
&simne;
?
&ncong; &NotTildeFullEqual;
˜
&asymp; &ap; &TildeTilde; &approx; &thkap; &thickapprox;
?
&nap; &NotTildeTilde; &napprox;
?
&ape; &approxeq;
?
&apid;
?
&bcong; &backcong;
?
&asympeq; &CupCap;
?
&bump; &HumpDownHump; &Bumpeq;
?
&bumpe; &HumpEqual; &bumpeq;
?
&esdot; &DotEqual; &doteq;
?
&eDot; &doteqdot;
?
&efDot; &fallingdotseq;
?
&erDot; &risingdotseq;
?
&colone; &coloneq; &Assign;
?
&ecolon; &eqcolon;
?
&ecir; &eqcirc;
?
&cire; &circeq;
?
&wedgeq;
?
&veeeq;
?
&trie; &triangleq;
?
&equest; &questeq;
?
&ne; &NotEqual;
=
&equiv; &Congruent;
?
&nequiv; &NotCongruent;
=
&le; &leq;
=
&ge; &GreaterEqual; &geq;
?
&lE; &LessFullEqual; &leqq;
?
&gE; &GreaterFullEqual; &geqq;
?
&lnE; &lneqq;
?
&gnE; &gneqq;
«
&Lt; &NestedLessLess; &ll;
»
&Gt; &NestedGreaterGreater; &gg;
?
&twixt; &between;
?
&NotCupCap;
?
&nlt; &NotLess; &nless;
?
&ngt; &NotGreater; &ngtr;
?
&nle; &NotLessEqual; &nleq;
?
&nge; &NotGreaterEqual; &ngeq;
?
&lsim; &LessTilde; &lesssim;
?
&gsim; &gtrsim; &GreaterTilde;
?
&nlsim; &NotLessTilde;
?
&ngsim; &NotGreaterTilde;
?
&lg; &lessgtr; &LessGreater;
?
&gl; &gtrless; &GreaterLess;
?
&ntlg; &NotLessGreater;
?
&ntgl; &NotGreaterLess;
?
&pr; &Precedes; &prec;
?
&sc; &Succeeds; &succ;
?
&prcue; &PrecedesSlantEqual; &preccurlyeq;
?
&sccue; &SucceedsSlantEqual; &succcurlyeq;
?
&prsim; &precsim; &PrecedesTilde;
?
&scsim; &succsim; &SucceedsTilde;
?
&npr; &nprec; &NotPrecedes;
?
&nsc; &nsucc; &NotSucceeds;
?
&sub; &subset;
?
&sup; &supset; &Superset;
?
&nsub;
?
&nsup;
?
&sube; &SubsetEqual; &subseteq;
?
&supe; &supseteq; &SupersetEqual;
?
&nsube; &nsubseteq; &NotSubsetEqual;
?
&nsupe; &nsupseteq; &NotSupersetEqual;
?
&subne; &subsetneq;
?
&supne; &supsetneq;
?
&cupdot;
?
&uplus; &UnionPlus;
?
&sqsub; &SquareSubset; &sqsubset;
?
&sqsup; &SquareSuperset; &sqsupset;
?
&sqsube; &SquareSubsetEqual; &sqsubseteq;
?
&sqsupe; &SquareSupersetEqual; &sqsupseteq;
?
&sqcap; &SquareIntersection;
?
&sqcup; &SquareUnion;
?
&oplus; &CirclePlus;
?
&ominus; &CircleMinus;
?
&otimes; &CircleTimes;
?
&osol;
?
&odot; &CircleDot;
?
&ocir; &circledcirc;
?
&oast; &circledast;
?
&odash; &circleddash;
?
&plusb; &boxplus;
?
&minusb; &boxminus;
?
&timesb; &boxtimes;
?
&sdotb; &dotsquare;
?
&vdash; &RightTee;
?
&dashv; &LeftTee;
?
&top; &DownTee;
?
&bottom; &bot; &perp; &UpTee;
?
&models;
?
&vDash; &DoubleRightTee;
?
&Vdash;
?
&Vvdash;
?
&VDash;
?
&nvdash;
?
&nvDash;
?
&nVdash;
?
&nVDash;
?
&prurel;
?
&vltri; &vartriangleleft; &LeftTriangle;
?
&vrtri; &vartriangleright; &RightTriangle;
?
&ltrie; &trianglelefteq; &LeftTriangleEqual;
?
&rtrie; &trianglerighteq; &RightTriangleEqual;
?
&origof;
?
&imof;
?
&mumap; &multimap;
?
&hercon;
?
&intcal; &intercal;
?
&veebar;
?
&barvee;
?
&angrtvb;
?
&lrtri;
?
&xwedge; &Wedge; &bigwedge;
?
&xvee; &Vee; &bigvee;
?
&xcap; &Intersection; &bigcap;
?
&xcup; &Union; &bigcup;
?
&diam; &diamond; &Diamond;
·
&sdot;
?
&sstarf; &Star;
?
&divonx; &divideontimes;
?
&bowtie;
?
&ltimes;
?
&rtimes;
?
&lthree; &leftthreetimes;
?
&rthree; &rightthreetimes;
?
&bsime; &backsimeq;
?
&cuvee; &curlyvee;
?
&cuwed; &curlywedge;
?
&Sub; &Subset;
?
&Sup; &Supset;
?
&Cap;
?
&Cup;
?
&fork; &pitchfork;
?
&epar;
?
&ltdot; &lessdot;
?
&gtdot; &gtrdot;
?
&Ll;
?
&Gg; &ggg;
?
&leg; &LessEqualGreater; &lesseqgtr;
?
&gel; &gtreqless; &GreaterEqualLess;
?
&cuepr; &curlyeqprec;
?
&cuesc; &curlyeqsucc;
?
&nprcue; &NotPrecedesSlantEqual;
?
&nsccue; &NotSucceedsSlantEqual;
?
&nsqsube; &NotSquareSubsetEqual;
?
&nsqsupe; &NotSquareSupersetEqual;
?
&lnsim;
?
&gnsim;
?
&prnsim; &precnsim;
?
&scnsim; &succnsim;
?
&nltri; &ntriangleleft; &NotLeftTriangle;
?
&nrtri; &ntriangleright; &NotRightTriangle;
?
&nltrie; &ntrianglelefteq; &NotLeftTriangleEqual;
?
&nrtrie; &ntrianglerighteq; &NotRightTriangleEqual;
?
&vellip;
?
&ctdot;
?
&utdot;
?
&dtdot;
?
&disin;
?
&isinsv;
?
&isins;
?
&isindot;
?
&notinvc;
?
&notinvb;
?
&isinE;
?
&nisd;
?
&xnis;
?
&nis;
?
&notnivc;
?
&notnivb;
?
&barwed; &barwedge;
?
&Barwed; &doublebarwedge;
?
&lceil; &LeftCeiling;
?
&rceil; &RightCeiling;
?
&lfloor; &LeftFloor;
?
&rfloor; &RightFloor;
?
&drcrop;
?
&dlcrop;
?
&urcrop;
?
&ulcrop;
¬
&bnot;
?
&profline;
?
&profsurf;
?
&telrec;
?
&target;
?
&ulcorn; &ulcorner;
?
&urcorn; &urcorner;
?
&dlcorn; &llcorner;
?
&drcorn; &lrcorner;
?
&frown; &sfrown;
?
&smile; &ssmile;
?
&cylcty;
?
&profalar;
?
&topbot;
?
&ovbar;
?
&solbar;
?
&angzarr;
?
&lmoust; &lmoustache;
?
&rmoust; &rmoustache;
?
&tbrk; &OverBracket;
?
&bbrk; &UnderBracket;
?
&bbrktbrk;
?
&OverParenthesis;
?
&UnderParenthesis;
?
&OverBrace;
?
&UnderBrace;
?
&trpezium;
?
&elinters;
?
&blank;
?
&oS; &circledS;
-
&boxh; &HorizontalLine;
¦
&boxv;
+
&boxdr;
+
&boxdl;
+
&boxur;
+
&boxul;
+
&boxvr;
¦
&boxvl;
-
&boxhd;
-
&boxhu;
+
&boxvh;
-
&boxH;
¦
&boxV;
+
&boxdR;
+
&boxDr;
+
&boxDR;
+
&boxdL;
+
&boxDl;
+
&boxDL;
+
&boxuR;
+
&boxUr;
+
&boxUR;
+
&boxuL;
+
&boxUl;
+
&boxUL;
¦
&boxvR;
¦
&boxVr;
¦
&boxVR;
¦
&boxvL;
¦
&boxVl;
¦
&boxVL;
-
&boxHd;
-
&boxhD;
-
&boxHD;
-
&boxHu;
-
&boxhU;
-
&boxHU;
+
&boxvH;
+
&boxVh;
+
&boxVH;
¯
&uhblk;
_
&lhblk;
¦
&block;
¦
&blk14;
¦
&blk12;
¦
&blk34;
?
&squ; &square; &Square;
?
&squf; &squarf; &blacksquare; &FilledVerySmallSquare;
?
&EmptyVerySmallSquare;
?
&rect;
?
&marker;
?
&fltns;
?
&xutri; &bigtriangleup;
?
&utrif; &blacktriangle;
?
&utri; &triangle;
?
&rtrif; &blacktriangleright;
?
&rtri; &triangleright;
?
&xdtri; &bigtriangledown;
?
&dtrif; &blacktriangledown;
?
&dtri; &triangledown;
?
&ltrif; &blacktriangleleft;
?
&ltri; &triangleleft;
?
&loz; &lozenge;
?
&cir;
?
&tridot;
?
&xcirc; &bigcirc;
?
&ultri;
?
&urtri;
?
&lltri;
?
&EmptySmallSquare;
?
&FilledSmallSquare;
?
&starf; &bigstar;
?
&star;
?
&phone;
?
&female;
?
&male;
?
&spades; &spadesuit;
?
&clubs; &clubsuit;
?
&hearts; &heartsuit;
?
&diams; &diamondsuit;
?
&sung;
?
&flat;
?
&natur; &natural;
?
&sharp;
?
&check; &checkmark;
?
&cross;
?
&malt; &maltese;
?
&sext;
|
&VerticalSeparator;
?
&lbbrk;
?
&rbbrk;
?
&lobrk; &LeftDoubleBracket;
?
&robrk; &RightDoubleBracket;
?
&lang; &LeftAngleBracket; &langle;
?
&rang; &RightAngleBracket; &rangle;
?
&Lang;
?
&Rang;
?
&loang;
?
&roang;
?
&xlarr; &longleftarrow; &LongLeftArrow;
?
&xrarr; &longrightarrow; &LongRightArrow;
?
&xharr; &longleftrightarrow; &LongLeftRightArrow;
?
&xlArr; &Longleftarrow; &DoubleLongLeftArrow;
?
&xrArr; &Longrightarrow; &DoubleLongRightArrow;
?
&xhArr; &Longleftrightarrow; &DoubleLongLeftRightArrow;
?
&xmap; &longmapsto;
?
&dzigrarr;
?
&nvlArr;
?
&nvrArr;
?
&nvHarr;
?
&Map;
?
&lbarr;
?
&rbarr; &bkarow;
?
&lBarr;
?
&rBarr; &dbkarow;
?
&RBarr; &drbkarow;
?
&DDotrahd;
?
&UpArrowBar;
?
&DownArrowBar;
?
&Rarrtl;
?
&latail;
?
&ratail;
?
&lAtail;
?
&rAtail;
?
&larrfs;
?
&rarrfs;
?
&larrbfs;
?
&rarrbfs;
?
&nwarhk;
?
&nearhk;
?
&searhk; &hksearow;
?
&swarhk; &hkswarow;
?
&nwnear;
?
&nesear; &toea;
?
&seswar; &tosa;
?
&swnwar;
?
&rarrc;
?
&cudarrr;
?
&ldca;
?
&rdca;
?
&cudarrl;
?
&larrpl;
?
&curarrm;
?
&cularrp;
?
&rarrpl;
?
&harrcir;
?
&Uarrocir;
?
&lurdshar;
?
&ldrushar;
?
&LeftRightVector;
?
&RightUpDownVector;
?
&DownLeftRightVector;
?
&LeftUpDownVector;
?
&LeftVectorBar;
?
&RightVectorBar;
?
&RightUpVectorBar;
?
&RightDownVectorBar;
?
&DownLeftVectorBar;
?
&DownRightVectorBar;
?
&LeftUpVectorBar;
?
&LeftDownVectorBar;
?
&LeftTeeVector;
?
&RightTeeVector;
?
&RightUpTeeVector;
?
&RightDownTeeVector;
?
&DownLeftTeeVector;
?
&DownRightTeeVector;
?
&LeftUpTeeVector;
?
&LeftDownTeeVector;
?
&lHar;
?
&uHar;
?
&rHar;
?
&dHar;
?
&luruhar;
?
&ldrdhar;
?
&ruluhar;
?
&rdldhar;
?
&lharul;
?
&llhard;
?
&rharul;
?
&lrhard;
?
&udhar; &UpEquilibrium;
?
&duhar; &ReverseUpEquilibrium;
?
&RoundImplies;
?
&erarr;
?
&simrarr;
?
&larrsim;
?
&rarrsim;
?
&rarrap;
?
&ltlarr;
?
&gtrarr;
?
&subrarr;
?
&suplarr;
?
&lfisht;
?
&rfisht;
?
&ufisht;
?
&dfisht;
?
&lopar;
?
&ropar;
?
&lbrke;
?
&rbrke;
?
&lbrkslu;
?
&rbrksld;
?
&lbrksld;
?
&rbrkslu;
?
&langd;
?

Not fully, pls track the link for fully document.

How to set all elements of an array to zero or any same value?

You could use memset, if you sure about the length.

memset(ptr, 0x00, length)

How would I get a cron job to run every 30 minutes?

You mention you are using OS X- I have used cronnix in the past. It's not as geeky as editing it yourself, but it helped me learn what the columns are in a jiffy. Just a thought.

Object of class mysqli_result could not be converted to string in

Before using the $result variable, you should use $row = mysqli_fetch_array($result) or mysqli_fetch_assoc() functions.

Like this:

$row = mysqli_fetch_array($result);

and use the $row array as you need.

How do you set the title color for the new Toolbar?

Option 1) The quick and easy way (Toolbar only)

Since appcompat-v7-r23 you can use the following attributes directly on your Toolbar or its style:

app:titleTextColor="@color/primary_text"
app:subtitleTextColor="@color/secondary_text"

If your minimum SDK is 23 and you use native Toolbar just change the namespace prefix to android.

In Java you can use the following methods:

toolbar.setTitleTextColor(Color.WHITE);
toolbar.setSubtitleTextColor(Color.WHITE);

These methods take a color int not a color resource ID!

Option 2) Override Toolbar style and theme attributes

layout/xxx.xml

<android.support.v7.widget.Toolbar
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:minHeight="?attr/actionBarSize"
    android:theme="@style/ThemeOverlay.MyApp.ActionBar"
    app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
    style="@style/Widget.MyApp.Toolbar.Solid"/>

values/styles.xml

<style name="Widget.MyApp.Toolbar.Solid" parent="Widget.AppCompat.ActionBar">
    <item name="android:background">@color/actionbar_color</item>
    <item name="android:elevation" tools:ignore="NewApi">4dp</item>
    <item name="titleTextAppearance">...</item>
</style>

<style name="ThemeOverlay.MyApp.ActionBar" parent="ThemeOverlay.AppCompat.ActionBar">
    <!-- Parent theme sets colorControlNormal to textColorPrimary. -->
    <item name="android:textColorPrimary">@color/actionbar_title_text</item>
</style>

Help! My icons changed color too!

@PeterKnut reported this affects the color of overflow button, navigation drawer button and back button. It also changes text color of SearchView.

Concerning the icon colors: The colorControlNormal inherits from

  • android:textColorPrimary for dark themes (white on black)
  • android:textColorSecondary for light themes (black on white)

If you apply this to the action bar's theme, you can customize the icon color.

<item name="colorControlNormal">#de000000</item>

There was a bug in appcompat-v7 up to r23 which required you to also override the native counterpart like so:

<item name="android:colorControlNormal" tools:ignore="NewApi">?colorControlNormal</item>

Help! My SearchView is a mess!

Note: This section is possibly obsolete.

Since you use the search widget which for some reason uses different back arrow (not visually, technically) than the one included with appcompat-v7, you have to set it manually in the app's theme. Support library's drawables get tinted correctly. Otherwise it would be always white.

<item name="homeAsUpIndicator">@drawable/abc_ic_ab_back_mtrl_am_alpha</item>

As for the search view text...there's no easy way. After digging through its source I found a way to get to the text view. I haven't tested this so please let me know in the comments if this didn't work. 

SearchView sv = ...; // get your search view instance in onCreateOptionsMenu
// prefix identifier with "android:" if you're using native SearchView
TextView tv = sv.findViewById(getResources().getIdentifier("id/search_src_text", null, null));
tv.setTextColor(Color.GREEN); // and of course specify your own color

Bonus: Override ActionBar style and theme attributes

Appropriate styling for a default action appcompat-v7 action bar would look like this:

<!-- ActionBar vs Toolbar. -->
<style name="Widget.MyApp.ActionBar.Solid" parent="Widget.AppCompat.ActionBar.Solid">
    <item name="background">@color/actionbar_color</item> <!-- No prefix. -->
    <item name="elevation">4dp</item> <!-- No prefix. -->
    <item name="titleTextStyle">...</item> <!-- Style vs appearance. -->
</style>

<style name="Theme.MyApp" parent="Theme.AppCompat">
    <item name="actionBarStyle">@style/Widget.MyApp.ActionBar.Solid</item>
    <item name="actionBarTheme">@style/ThemeOverlay.MyApp.ActionBar</item>
    <item name="actionBarPopupTheme">@style/ThemeOverlay.AppCompat.Light</item>
</style>

Accessing Object Memory Address

The Python manual has this to say about id():

Return the "identity'' of an object. This is an integer (or long integer) which is guaranteed to be unique and constant for this object during its lifetime. Two objects with non-overlapping lifetimes may have the same id() value. (Implementation note: this is the address of the object.)

So in CPython, this will be the address of the object. No such guarantee for any other Python interpreter, though.

Note that if you're writing a C extension, you have full access to the internals of the Python interpreter, including access to the addresses of objects directly.

System.Security.SecurityException when writing to Event Log

This exception was occurring for me from a .NET console app running as a scheduled task, and I was trying to do basically the same thing - create a new Event Source and write to the event log.

In the end, setting full permissions for the user under which the task was running on the following keys did the trick for me:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\eventlog\Application
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\eventlog\Security
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\eventlog

Java string split with "." (dot)

The dot "." is a special character in java regex engine, so you have to use "\\." to escape this character:

final String extensionRemoved = filename.split("\\.")[0];

I hope this helps

SQLDataReader Row Count

Maybe you can try this: though please note - This pulls the column count, not the row count

 using (SqlDataReader reader = command.ExecuteReader())
 {
     while (reader.Read())
     {
         int count = reader.VisibleFieldCount;
         Console.WriteLine(count);
     }
 }

How do I run a node.js app as a background service?

If you are running nodejs in linux server, I think this is the best way.

Create a service script and copy to /etc/init/nodejs.conf

start service: sudo service nodejs start

stop service: sudo service nodejs stop

Sevice script

description "DManager node.js server - Last Update: 2012-08-06"
author      "Pedro Muniz - [email protected]"

env USER="nodejs" #you have to create this user 
env APPNAME="nodejs" #you can change the service name
env WORKDIR="/home/<project-home-dir>" #set your project home folder here
env COMMAND="/usr/bin/node <server name>" #app.js ?

# used to be: start on startup
# until we found some mounts weren't ready yet while booting:
start on started mountall
stop on shutdown

# Automatically Respawn:
respawn
respawn limit 99 5

pre-start script
    sudo -u $USER echo "[`date -u +%Y-%m-%dT%T.%3NZ`] (sys) Starting" >> /var/log/$APPNAME.log
end script

script
    # Not sure why $HOME is needed, but we found that it is:
    export HOME="<project-home-dir>"  #set your project home folder here
    export NODE_PATH="<project node_path>"

    #log file, grant permission to nodejs user
    exec start-stop-daemon --start --make-pidfile --pidfile /var/run/$APPNAME.pid --chuid $USER --chdir $WORKDIR --exec $COMMAND >> /var/log/$APPNAME.log 2>&1
end script

post-start script
   # Optionally put a script here that will notifiy you node has (re)started
   # /root/bin/hoptoad.sh "node.js has started!"
end script

pre-stop script
    sudo -u $USER echo "[`date -u +%Y-%m-%dT%T.%3NZ`] (sys) Stopping" >> /var/log/$APPNAME.log
end script

Is there an online application that automatically draws tree structures for phrases/sentences?

In short, yes. I assume you're looking to parse English: for that you can use the Link Parser from Carnegie Mellon.

It is important to remember that there are many theories of syntax, that can give completely different-looking phrase structure trees; further, the trees are different for each language, and tools may not exist for those languages.

As a note for the future: if you need a sentence parsed out and tag it as linguistics (and syntax or whatnot, if that's available), someone can probably parse it out for you and guide you through it.

Switch tabs using Selenium WebDriver with Java

With Selenium 2.53.1 using firefox 47.0.1 as the WebDriver in Java: no matter how many tabs I opened, "driver.getWindowHandles()" would only return one handle so it was impossible to switch between tabs.

Once I started using Chrome 51.0, I could get all handles. The following code show how to access multiple drivers and multiple tabs within each driver.

// INITIALIZE TWO DRIVERS (THESE REPRESENT SEPARATE CHROME WINDOWS)
driver1 = new ChromeDriver();
driver2 = new ChromeDriver();

// LOOP TO OPEN AS MANY TABS AS YOU WISH
for(int i = 0; i < TAB_NUMBER; i++) {
   driver1.findElement(By.cssSelector("body")).sendKeys(Keys.CONTROL + "t");
   // SLEEP FOR SPLIT SECOND TO ALLOW DRIVER TIME TO OPEN TAB
   Thread.sleep(100);

// STORE TAB HANDLES IN ARRAY LIST FOR EASY ACCESS
ArrayList tabs1 = new ArrayList<String> (driver1.getWindowHandles());

// REPEAT FOR THE SECOND DRIVER (SECOND CHROME BROWSER WINDOW)

// LOOP TO OPEN AS MANY TABS AS YOU WISH
for(int i = 0; i < TAB_NUMBER; i++) {
   driver2.findElement(By.cssSelector("body")).sendKeys(Keys.CONTROL + "t");
   // SLEEP FOR SPLIT SECOND TO ALLOW DRIVER TIME TO OPEN TAB
   Thread.sleep(100);

// STORE TAB HANDLES IN ARRAY LIST FOR EASY ACCESS
ArrayList tabs2 = new ArrayList<String> (driver1.getWindowHandles());

// NOW PERFORM DESIRED TASKS WITH FIRST BROWSER IN ANY TAB
for(int ii = 0; ii <= TAB_NUMBER; ii++) {
   driver1.switchTo().window(tabs1.get(ii));
   // LOGIC FOR THAT DRIVER'S CURRENT TAB
}

// PERFORM DESIRED TASKS WITH SECOND BROWSER IN ANY TAB
for(int ii = 0; ii <= TAB_NUMBER; ii++) {
   drvier2.switchTo().window(tabs2.get(ii));
   // LOGIC FOR THAT DRIVER'S CURRENT TAB
}

Hopefully that gives you a good idea of how to manipulate multiple tabs in multiple browser windows.

Docker: Multiple Dockerfiles in project

Use docker-compose and multiple Dockerfile in separate directories

Don't rename your Dockerfile to Dockerfile.db or Dockerfile.web, it may not be supported by your IDE and you will lose syntax highlighting.

As Kingsley Uchnor said, you can have multiple Dockerfile, one per directory, which represent something you want to build.

I like to have a docker folder which holds each applications and their configuration. Here's an example project folder hierarchy for a web application that has a database.

docker-compose.yml
docker
+-- web
¦   +-- Dockerfile
+-- db
    +-- Dockerfile

docker-compose.yml example:

version: '3'
services:
  web:
    # will build ./docker/web/Dockerfile
    build: ./docker/web
    ports:
     - "5000:5000"
    volumes:
     - .:/code
  db:
    # will build ./docker/db/Dockerfile
    build: ./docker/db
    ports:
      - "3306:3306"
  redis:
    # will use docker hub's redis prebuilt image from here:
    # https://hub.docker.com/_/redis/
    image: "redis:alpine"

docker-compose command line usage example:

# The following command will create and start all containers in the background
# using docker-compose.yml from current directory
docker-compose up -d

# get help
docker-compose --help

In case you need files from previous folders when building your Dockerfile

You can still use the above solution and place your Dockerfile in a directory such as docker/web/Dockerfile, all you need is to set the build context in your docker-compose.yml like this:

version: '3'
services:
  web:
    build:
      context: .
      dockerfile: ./docker/web/Dockerfile
    ports:
     - "5000:5000"
    volumes:
     - .:/code

This way, you'll be able to have things like this:

config-on-root.ini
docker-compose.yml
docker
+-- web
    +-- Dockerfile
    +-- some-other-config.ini

and a ./docker/web/Dockerfile like this:

FROM alpine:latest

COPY config-on-root.ini /
COPY docker/web/some-other-config.ini /

Here are some quick commands from tldr docker-compose. Make sure you refer to official documentation for more details.

C# Java HashMap equivalent

Check out the documentation on MSDN for the Hashtable class.

Represents a collection of key-and-value pairs that are organized based on the hash code of the key.

Also, keep in mind that this is not thread-safe.

How to execute a .sql script from bash

If you want to run a script to a database:

mysql -u user -p data_base_name_here < db.sql

Server configuration is missing in Eclipse

this worked for me

  1. In the Server's tab in Eclipse, Stop the Tomcat server

  2. Right-click the server and select "Clean..."

  3. Right-click the server again and select "Clean Tomcat Work Directory..."

  4. In the Eclipse, select the top-level menu option, Project > Clean ...

  5. Be sure your project is selected and click Ok

  6. Restart Eclipse

Regular expression to match URLs in Java

When using regular expressions from RegexBuddy's library, make sure to use the same matching modes in your own code as the regex from the library. If you generate a source code snippet on the Use tab, RegexBuddy will automatically set the correct matching options in the source code snippet. If you copy/paste the regex, you have to do that yourself.

In this case, as others pointed out, you missed the case insensitivity option.

SQL Not Like Statement not working

mattgcon,

Should work, do you get more rows if you run the same SQL with the "NOT LIKE" line commented out? If not, check the data. I know you mentioned in your question, but check that the actual SQL statement is using that clause. The other answers with NULL are also a good idea.

In bash, how to store a return value in a variable?

Something like this could be used, and still maintaining meanings of return (to return control signals) and echo (to return information) and logging statements (to print debug/info messages).

v_verbose=1
v_verbose_f=""         # verbose file name
FLAG_BGPID=""

e_verbose() {
        if [[ $v_verbose -ge 0 ]]; then
                v_verbose_f=$(tempfile)
                tail -f $v_verbose_f &
                FLAG_BGPID="$!"
        fi
}

d_verbose() {
        if [[ x"$FLAG_BGPID" != "x" ]]; then
                kill $FLAG_BGPID > /dev/null
                FLAG_BGPID=""
                rm -f $v_verbose_f > /dev/null
        fi
}

init() {
        e_verbose

        trap cleanup SIGINT SIGQUIT SIGKILL SIGSTOP SIGTERM SIGHUP SIGTSTP
}

cleanup() {
        d_verbose
}

init

fun1() {
    echo "got $1" >> $v_verbose_f
    echo "got $2" >> $v_verbose_f
    echo "$(( $1 + $2 ))"
    return 0
}

a=$(fun1 10 20)
if [[ $? -eq 0 ]]; then
    echo ">>sum: $a"
else
    echo "error: $?"
fi
cleanup

In here, I'm redirecting debug messages to separate file, that is watched by tail, and if there is any changes then printing the change, trap is used to make sure that background process always ends.

This behavior can also be achieved using redirection to /dev/stderr, But difference can be seen at the time of piping output of one command to input of other command.

Wait until all jQuery Ajax requests are done?

This is working for me It's very simple

return $.ajax({
  type: 'POST',
  url: urlBaseUrl
  data: {someData:someData},
  dataType: "json",
  success: function(resultData) { 
  }
});

jQuery getJSON save result into variable

You can't get value when calling getJSON, only after response.

var myjson;
$.getJSON("http://127.0.0.1:8080/horizon-update", function(json){
    myjson = json;
});

SQL to Entity Framework Count Group-By

with EF 6.2 it worked for me 

  var query = context.People
               .GroupBy(p => new {p.name})
               .Select(g => new { name = g.Key.name, count = g.Count() });

Why doesn't Dijkstra's algorithm work for negative weight edges?

Correctness of Dijkstra's algorithm:

We have 2 sets of vertices at any step of the algorithm. Set A consists of the vertices to which we have computed the shortest paths. Set B consists of the remaining vertices.

Inductive Hypothesis: At each step we will assume that all previous iterations are correct.

Inductive Step: When we add a vertex V to the set A and set the distance to be dist[V], we must prove that this distance is optimal. If this is not optimal then there must be some other path to the vertex V that is of shorter length.

Suppose this some other path goes through some vertex X.

Now, since dist[V] <= dist[X] , therefore any other path to V will be atleast dist[V] length, unless the graph has negative edge lengths.

Thus for dijkstra's algorithm to work, the edge weights must be non negative.

How to install a specific version of a package with pip?

Use ==:

pip install django_modeltranslation==0.4.0-beta2

Why is Chrome showing a "Please Fill Out this Field" tooltip on empty fields?

As I mentioned in your other question:

The problem to do with that fact, that you invented your own non-standard attributes (which you shouldn't have done in the first place), and now new standardized attributes (or attributes in the process of being standardized) are colliding with them.

The proper solution is to completely remove your invented attributes and replace them with something sensible, for example classes (class="Montantetextfield fieldname-Montante required allow-decimal-values"), or store them in JavaScript:

var validationData = {
  "Montante": {fieldname: "Montante", required: true, allowDecimalValues: true}
}

If the proper solution isn't viable, you'll have to rename them. In that case you should use the prefix data-... because that is reserved by HTML5 for such purposes, and it's less likely to collide with something - but it still could, so you should seriously consider the first solution - even it is more work to change.

How to determine the encoding of text?

Another option for working out the encoding is to use libmagic (which is the code behind the file command). There are a profusion of python bindings available.

The python bindings that live in the file source tree are available as the python-magic (or python3-magic) debian package. It can determine the encoding of a file by doing:

import magic

blob = open('unknown-file', 'rb').read()
m = magic.open(magic.MAGIC_MIME_ENCODING)
m.load()
encoding = m.buffer(blob)  # "utf-8" "us-ascii" etc

There is an identically named, but incompatible, python-magic pip package on pypi that also uses libmagic. It can also get the encoding, by doing:

import magic

blob = open('unknown-file', 'rb').read()
m = magic.Magic(mime_encoding=True)
encoding = m.from_buffer(blob)

Create a rounded button / button with border-radius in Flutter

You can use ButtonTheme() also

enter image description here

Here is a example code -

ButtonTheme(
              minWidth: 200.0,
              shape: RoundedRectangleBorder(
                  borderRadius: BorderRadius.circular(18.0),
                  side: BorderSide(color: Colors.green)),
              child: RaisedButton(
                elevation: 5.0,
                hoverColor: Colors.green,
                color: Colors.amber,
                child: Text(
                  "Place Order",
                  style: TextStyle(
                      color: Colors.white, fontWeight: FontWeight.bold),
                ),
                onPressed: () {},
              ),
            ),

SQL Server procedure declare a list

I've always found it easier to invert the test against the list in situations like this. For instance...

SELECT 
    field0, field1, field2 
FROM 
    my_table 
WHERE 
    ',' + @mysearchlist + ',' LIKE '%,' + CAST(field3 AS VARCHAR) + ',%'

This means that there is no complicated mish-mash required for the values that you are looking for.

As an example, if our list was ('1,2,3'), then we add a comma to the start and end of our list like so: ',' + @mysearchlist + ','.

We also do the same for the field value we're looking for and add wildcards: '%,' + CAST(field3 AS VARCHAR) + ',%' (notice the % and the , characters).

Finally we test the two using the LIKE operator: ',' + @mysearchlist + ',' LIKE '%,' + CAST(field3 AS VARCHAR) + ',%'.

How to implement debounce in Vue2?

 
 public debChannel = debounce((key) => this.remoteMethodChannelName(key), 200)

vue-property-decorator

How to install JRE 1.7 on Mac OS X and use it with Eclipse?

You need to tell Eclipse which JDK/JRE's you have installed and where they are located.

This is somewhat burried in the Eclipse preferences: In the Window-Menu select "Preferences". In the Preferences Tree, open the Node "Java" and select "Installed JRE's". Then click on the "Add"-Button in the Panel and select "Standard VM", "Next" and for "JRE Home" click on the "Directory"-Button and select the top level folder of the JDK you want to add.

Its easier than the description may make it look.

Converting string to Date and DateTime

Use strtotime() on your first date then date('Y-m-d') to convert it back:

$time = strtotime('10/16/2003');

$newformat = date('Y-m-d',$time);

echo $newformat;
// 2003-10-16

Make note that there is a difference between using forward slash / and hyphen - in the strtotime() function. To quote from php.net:

Dates in the m/d/y or d-m-y formats are disambiguated by looking at the separator between the various components: if the separator is a slash (/), then the American m/d/y is assumed; whereas if the separator is a dash (-) or a dot (.), then the European d-m-y format is assumed.

To avoid potential ambiguity, it's best to use ISO 8601 (YYYY-MM-DD) dates or DateTime::createFromFormat() when possible.

Unable to connect with remote debugger

Trouble shooting React native with React Cli and Typescript/js (Android Emulator)

  1. Check if 'android/src/mai/assets/index.android.bundle' is available. If no Create index.android.bundle file in 'android/src/main/assets'
  2. If above path not available then create the path then file 3.Run for bundling : react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res

4.a. By default development server runs on 8081 port. Run 'react-native start' then on browser check if 'http://localhost:8081' and 'http://yourIP:8081' works. If yes then Open application in Android Emulator (react-native run-android)

  • Click Ctrl + M
  • Select Settings
  • Select Debug Server Host and Port For Device
  • Add 'YourIPAddress:8081' e.g. 10.0.2.2:8081

4.b If http://localhost:8081 not working then run react-native port=8088(or any port)once successfully executed. Check on browser http://localhost:8088 and http://yourIP:8088 works. Yes then Open application in Android Emulator (react-native run-android)

  • Click 'Ctrl + M'
  • Select Settings-
  • Select Debug Server Host and Port For Device-
  • Add 'YourIPAddress:8081' e.g. 10.0.2.2:8088

YourIPAddress : Open command promt -> write 'ipconfig' -> copy IPv4 address

Change user-agent for Selenium web-driver

There is no way in Selenium to read the request or response headers. You could do it by instructing your browser to connect through a proxy that records this kind of information.

Setting the User Agent in Firefox

The usual way to change the user agent for Firefox is to set the variable "general.useragent.override" in your Firefox profile. Note that this is independent from Selenium.

You can direct Selenium to use a profile different from the default one, like this:

from selenium import webdriver
profile = webdriver.FirefoxProfile()
profile.set_preference("general.useragent.override", "whatever you want")
driver = webdriver.Firefox(profile)

Setting the User Agent in Chrome

With Chrome, what you want to do is use the user-agent command line option. Again, this is not a Selenium thing. You can invoke Chrome at the command line with chrome --user-agent=foo to set the agent to the value foo.

With Selenium you set it like this:

from selenium import webdriver
from selenium.webdriver.chrome.options import Options
opts = Options()
opts.add_argument("user-agent=whatever you want")

driver = webdriver.Chrome(chrome_options=opts)

Both methods above were tested and found to work. I don't know about other browsers.

Getting the User Agent

Selenium does not have methods to query the user agent from an instance of WebDriver. Even in the case of Firefox, you cannot discover the default user agent by checking what general.useragent.override would be if not set to a custom value. (This setting does not exist before it is set to some value.)

Once the browser is started, however, you can get the user agent by executing:

agent = driver.execute_script("return navigator.userAgent")

The agent variable will contain the user agent.

What characters are allowed in an email address?

In my PHP I use this check 

<?php
if (preg_match(
'/^(?:[\w\!\#\$\%\&\'\*\+\-\/\=\?\^\`\{\|\}\~]+\.)*[\w\!\#\$\%\&\'\*\+\-\/\=\?\^\`\{\|\}\~]+@(?:(?:(?:[a-zA-Z0-9_](?:[a-zA-Z0-9_\-](?!\.)){0,61}[a-zA-Z0-9_-]?\.)+[a-zA-Z0-9_](?:[a-zA-Z0-9_\-](?!$)){0,61}[a-zA-Z0-9_]?)|(?:\[(?:(?:[01]?\d{1,2}|2[0-4]\d|25[0-5])\.){3}(?:[01]?\d{1,2}|2[0-4]\d|25[0-5])\]))$/',
"tim'[email protected]"        
)){
    echo "legit email";
} else {
    echo "NOT legit email";
}
?>

try it yourself http://phpfiddle.org/main/code/9av6-d10r

C# - Making a Process.Start wait until the process has start-up

First of all: I know this is rather old but there still is not an accepted answer, so perhaps my approach will help someone else. :)

What I did to solve this is: 

process.Start();

while (true)
{
    try
    {
        var time = process.StartTime;
        break;
    }
    catch (Exception) {}
}

The association var time = process.StartTime will throw an exception as long as process did not start. So once it passes, it is safe to assume process is running and to work with it further. I am using this to wait for java process to start up, since it takes some time. This way it should be independent on what machine the application is running rather than using Thread.Sleep().

I understand this is not very clean solution, but the only one that should be performance independent I could think of.

Regex for allowing alphanumeric,-,_ and space

 
var string = 'test- _ 0Test';
string.match(/^[-_ a-zA-Z0-9]+$/)

JavaScript file upload size validation

Works for Dynamic and Static File Element

Javascript Only Solution

_x000D_
_x000D_ 
function ValidateSize(file) {
        var FileSize = file.files[0].size / 1024 / 1024; // in MiB
        if (FileSize > 2) {
            alert('File size exceeds 2 MiB');
           // $(file).val(''); //for clearing with Jquery
        } else {

        }
    }
_x000D_ 
 <input onchange="ValidateSize(this)" type="file">
_x000D_
_x000D_
_x000D_

IOException: Too many open files

You can handle the fds yourself. The exec in java returns a Process object. Intermittently check if the process is still running. Once it has completed close the processes STDERR, STDIN, and STDOUT streams (e.g. proc.getErrorStream.close()). That will mitigate the leaks.

Facebook API: Get fans of / people who like a page

There is a "way" to get some part of fan list with their profile ids of some fanpage without token.

  1. Get id of a fanpage with public graph data: http://graph.facebook.com/cocacola - Coca-Cola has 40796308305. UPDATE 2016.04.30: Facebook now requires access token to get page_id through graph so you can parse fanpage HTML syntax to get this id without any authorization from https://www.facebook.com/{PAGENAME} as in example below based on og tags present on the fanpage.
  2. Get Coca-Cola's "like plugin" iframe display directly with some modified params: http://www.facebook.com/plugins/fan.php?connections=100&id=40796308305
  3. Now check the page sources, there are a lot of fans with links to their profiles, where you can find their profile ids or nicknames like: http://www.facebook.com/michal.semeniuk .
  4. If you are interested only in profile ids use the graph api again - it will give you profile id directly: http://graph.facebook.com/michal.semeniuk UPDATE 2016.04.30: Facebook now requires access token to get such info. You can parse profile HTML syntax, just like in the first step meta tag is your best friend: <meta property="al:android:url" content="fb://profile/{PROFILE_ID}" />

And now is the best part: try to refresh (F5) the link in point 2.. There is a new full set of another fans of Coca-Cola. Take only uniques and you will be able to get some nice, almost full list of fans.

-- UPDATE 2013.08.06 --

Why don't you use my ready PHP script to fetch some fans? :)

UPDATE 2016.04.30: Updated example script to use new methods after Facebook started to require access token to get public data from graph api.

function fetch_fb_fans($fanpage_name, $no_of_retries = 10, $pause = 500000 /* 500ms */){
    $ret = array();
    // prepare real like user agent and accept headers
    $context = stream_context_create(array('http' => array('header' => 'User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/49.0.2623.108 Chrome/49.0.2623.108 Safari/537.36\r\nAccept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8\r\nAccept-encoding: gzip, deflate, sdch\r\nAccept-language: en-US,en;q=0.8,pl;q=0.6\r\n')));
    // get page id from facebook html og tags for mobile apps
    $fanpage_html = file_get_contents('https://www.facebook.com/' . $fanpage_name, false, $context);
    if(!preg_match('{fb://page/(\d+)}', $fanpage_html, $id_matches)){
        // invalid fanpage name
        return $ret;
    }
    $url = 'http://www.facebook.com/plugins/fan.php?connections=100&id=' . $id_matches[1];
    for($a = 0; $a < $no_of_retries; $a++){
        $like_html = file_get_contents($url, false, $context);
        preg_match_all('{href="https?://www\.facebook\.com/([a-zA-Z0-9\._-]+)" class="link" data-jsid="anchor" target="_blank"}', $like_html, $matches);
        if(empty($matches[1])){
            // failed to fetch any fans - convert returning array, cause it might be not empty
            return array_keys($ret);
        }else{
            // merge profiles as array keys so they will stay unique
            $ret = array_merge($ret, array_flip($matches[1]));
        }
        // don't get banned as flooder
        usleep($pause);
    }
    return array_keys($ret);
}

print_r(fetch_fb_fans('TigerPolska', 2, 400000));

Tomcat 7 "SEVERE: A child container failed during start"

for me one case was I just missed to maven update project which caused the same issue

maven update project and try if you see any errors in POM.xml

Azure SQL Database "DTU percentage" metric

From this document, this DTU percent is determined by this query:

SELECT end_time,   
  (SELECT Max(v)    
   FROM (VALUES (avg_cpu_percent), (avg_data_io_percent), 
(avg_log_write_percent)) AS    
   value(v)) AS [avg_DTU_percent]   
FROM sys.dm_db_resource_stats;

looks like the max of avg_cpu_percent, avg_data_io_percent and avg_log_write_percent

Reference:

https://docs.microsoft.com/en-us/sql/relational-databases/system-dynamic-management-views/sys-dm-db-resource-stats-azure-sql-database

How to modify memory contents using GDB?

As Nikolai has said you can use the gdb 'set' command to change the value of a variable.

You can also use the 'set' command to change memory locations. eg. Expanding on Nikolai's example:

(gdb) l
6       {
7           int i;
8           struct file *f, *ftmp;
9
(gdb) set variable i = 10
(gdb) p i
$1 = 10

(gdb) p &i
$2 = (int *) 0xbfbb0000
(gdb) set *((int *) 0xbfbb0000) = 20
(gdb) p i
$3 = 20

This should work for any valid pointer, and can be cast to any appropriate data type.

This Handler class should be static or leaks might occur: IncomingHandler

This way worked well for me, keeps code clean by keeping where you handle the message in its own inner class.

The handler you wish to use

Handler mIncomingHandler = new Handler(new IncomingHandlerCallback());

The inner class

class IncomingHandlerCallback implements Handler.Callback{

        @Override
        public boolean handleMessage(Message message) {

            // Handle message code

            return true;
        }
}

"This operation requires IIS integrated pipeline mode."

I was having the same issue and I solved it doing the following:

  1. In Visual Studio, select "Project properties".

  2. Select the "Web" Tab.

  3. Select "Use Local IIS Web server".

  4. Check "Use IIS Express"

Get a list of numbers as input from the user

It is much easier to parse a list of numbers separated by spaces rather than trying to parse Python syntax:

Python 3:

s = input()
numbers = list(map(int, s.split()))

Python 2:

s = raw_input()
numbers = map(int, s.split())

Unsetting array values in a foreach loop

You would also need a 

$i--;

after each unset to not skip an element/

Because when you unset $item[45], the next element in the for-loop should be $item[45] - which was [46] before unsetting. If you would not do this, you'd always skip an element after unsetting.

How to get anchor text/href on click using jQuery?

Edited to reflect update to question

$(document).ready(function() {
    $(".res a").click(function() {
        alert($(this).attr("href"));
    });
});

How to retrieve an element from a set without removing it?

Least code would be:

>>> s = set([1, 2, 3])
>>> list(s)[0]
1

Obviously this would create a new list which contains each member of the set, so not great if your set is very large.

Certificate has either expired or has been revoked

I just unchecked "Automatically manage signing and checked it again with selecting the Team and it worked for me enter image description here

How can I get the active screen dimensions?

WinForms

For multi-monitor setups you will also need account for the X and Y position:

Rectangle activeScreenDimensions = Screen.FromControl(this).Bounds;
this.Size = new Size(activeScreenDimensions.Width + activeScreenDimensions.X, activeScreenDimensions.Height + activeScreenDimensions.Y);

Save base64 string as PDF at client side with JavaScript

You should be able to download the file using

window.open("data:application/pdf;base64," + Base64.encode(out));

How to close a JavaFX application on window close?

getContentPane.remove(jfxPanel);

try it (:

Accessing nested JavaScript objects and arrays by string path

If you need to access different nested key without knowing it at coding time (it will be trivial to address them) you can use the array notation accessor:

var part1name = someObject['part1']['name'];
var part2quantity = someObject['part2']['qty'];
var part3name1 =  someObject['part3'][0]['name'];

They are equivalent to the dot notation accessor and may vary at runtime, for example:

var part = 'part1';
var property = 'name';

var part1name = someObject[part][property];

is equivalent to 

var part1name = someObject['part1']['name'];

or 

var part1name = someObject.part1.name;

I hope this address your question...

EDIT

I won't use a string to mantain a sort of xpath query to access an object value. As you have to call a function to parse the query and retrieve the value I would follow another path (not :

var part1name = function(){ return this.part1.name; }
var part2quantity = function() { return this['part2']['qty']; }
var part3name1 =  function() { return this.part3[0]['name'];}

// usage: part1name.apply(someObject);

or, if you are uneasy with the apply method 

var part1name = function(obj){ return obj.part1.name; }
var part2quantity = function(obj) { return obj['part2']['qty']; }
var part3name1 =  function(obj) { return obj.part3[0]['name'];}

// usage: part1name(someObject);

The functions are shorter, clearer, the interpreter check them for you for syntax errors and so on.

By the way, I feel that a simple assignment made at right time will be sufficent...

How do I properly force a Git push?

This was our solution for replacing master on a corporate gitHub repository while maintaining history.

push -f to master on corporate repositories is often disabled to maintain branch history. This solution worked for us.

git fetch desiredOrigin
git checkout -b master desiredOrigin/master // get origin master

git checkout currentBranch  // move to target branch
git merge -s ours master  // merge using ours over master
// vim will open for the commit message
git checkout master  // move to master
git merge currentBranch  // merge resolved changes into master

push your branch to desiredOrigin and create a PR

Why is “while ( !feof (file) )” always wrong?

No it's not always wrong. If your loop condition is "while we haven't tried to read past end of file" then you use while (!feof(f)). This is however not a common loop condition - usually you want to test for something else (such as "can I read more"). while (!feof(f)) isn't wrong, it's just used wrong.

How to disable mouse right click on a web page?

It's unprofessional, anyway this will work with javascript enabled:

document.oncontextmenu = document.body.oncontextmenu = function() {return false;}

You may also want to show a message to the user before returning false.

However I have to say that this should not be done generally because it limits users options without resolving the issue (in fact the context menu can be very easily enabled again.).

The following article better explains why this should not be done and what other actions can be taken to solve common related issues: http://articles.sitepoint.com/article/dont-disable-right-click

Kill Attached Screen in Linux

Suppose your screen id has a pattern. Then you can use the following code to kill all the attached screen at once. 

result=$(screen -ls | grep 'pattern_of_screen_id' -o)
for i in $result; 
do      
    `screen -X -S $i quit`;
done

How to get a index value from foreach loop in jstl

 
<a onclick="getCategoryIndex(${myIndex.index})" href="#">${categoryName}</a>

above line was giving me an error. So I wrote down in below way which is working fine for me.

<a onclick="getCategoryIndex('<c:out value="${myIndex.index}"/>')" href="#">${categoryName}</a>

Maybe someone else might get same error. Look at this guys!

What is special about /dev/tty?

The 'c' means it's a character device. tty is a special file representing the 'controlling terminal' for the current process.

Character Devices

Unix supports 'device files', which aren't really files at all, but file-like access points to hardware devices. A 'character' device is one which is interfaced byte-by-byte (as opposed to buffered IO).

TTY

/dev/tty is a special file, representing the terminal for the current process. So, when you echo 1 > /dev/tty, your message ('1') will appear on your screen. Likewise, when you cat /dev/tty, your subsequent input gets duplicated (until you press Ctrl-C).

/dev/tty doesn't 'contain' anything as such, but you can read from it and write to it (for what it's worth). I can't think of a good use for it, but there are similar files which are very useful for simple IO operations (e.g. /dev/ttyS0 is normally your serial port)

This quote is from http://tldp.org/HOWTO/Text-Terminal-HOWTO-7.html#ss7.3 :

/dev/tty stands for the controlling terminal (if any) for the current process. To find out which tty's are attached to which processes use the "ps -a" command at the shell prompt (command line). Look at the "tty" column. For the shell process you're in, /dev/tty is the terminal you are now using. Type "tty" at the shell prompt to see what it is (see manual pg. tty(1)). /dev/tty is something like a link to the actually terminal device name with some additional features for C-programmers: see the manual page tty(4).

Here is the man page: http://linux.die.net/man/4/tty

Syntax for async arrow function

Basic Example

folder = async () => {
    let fold = await getFold();
    //await localStorage.save('folder');
    return fold;
  };

here-document gives 'unexpected end of file' error

The line that starts or ends the here-doc probably has some non-printable or whitespace characters (for example, carriage return) which means that the second "EOF" does not match the first, and doesn't end the here-doc like it should. This is a very common error, and difficult to detect with just a text editor. You can make non-printable characters visible for example with cat:

cat -A myfile.sh

Once you see the output from cat -A the solution will be obvious: remove the offending characters.

Assembly - JG/JNLE/JL/JNGE after CMP

Wikibooks has a fairly good summary of jump instructions. Basically, there's actually two stages:

cmp_instruction op1, op2

Which sets various flags based on the result, and

jmp_conditional_instruction address

which will execute the jump based on the results of those flags.

Compare (cmp) will basically compute the subtraction op1-op2, however, this is not stored; instead only flag results are set. So if you did cmp eax, ebx that's the same as saying eax-ebx - then deciding based on whether that is positive, negative or zero which flags to set.

More detailed reference here.

The operation couldn’t be completed. (com.facebook.sdk error 2.) ios6

This worked for me:

  • Go to the settings app of your iPhone.
  • Open your Facebook Settings
  • Scroll down to your app and make sure your app allows facebook interaction.

This could happen on any device, therefore in your app you will have to make sure to handle this error correctly. I reckon you give the user feedback why Login With Facebook failed and ask the user to check their Facebook settings on their device.

 - (void)facebookSessionStateChanged:(FBSession *)session state:(FBSessionState)state error:(NSError *)error
{
    switch (state) {
        case FBSessionStateOpen:
            // handle successful login here
        case FBSessionStateClosed:
        case FBSessionStateClosedLoginFailed:
            [FBSession.activeSession closeAndClearTokenInformation];

            if (error) {
                // handle error here, for example by showing an alert to the user
                UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Could not login with Facebook"
                                                                message:@"Facebook login failed. Please check your Facebook settings on your phone."
                                                               delegate:nil
                                                      cancelButtonTitle:@"OK"
                                                  otherButtonTitles:nil];
                [alert show];
            }
            break;
        default:
            break;
    }

How to access full source of old commit in BitBucket?

I was trying to figure out if it's possible to browse the code of an earlier commit like you can on GitHub and it brought me here. I used the information I found here, and after fiddling around with the urls, I actually found a way to browse code of old commits as well.

When you're browsing your code the URL is something like:

https://bitbucket.org/user/repo/src/

and by adding a commit hash at the end like this:

https://bitbucket.org/user/repo/src/a0328cb

You can browse the code at the point of that commit. I don't understand why there's no dropdown box for choosing a commit directly, the feature is already there. Strange.

Git: How to reset a remote Git repository to remove all commits?

Completely reset?

  1. Delete the .git directory locally.

  2. Recreate the git repostory:

    $ cd (project-directory)
$ git init
$ (add some files)
$ git add .
$ git commit -m 'Initial commit'

  3. Push to remote server, overwriting. Remember you're going to mess everyone else up doing this … you better be the only client.

    $ git remote add origin <url>
$ git push --force --set-upstream origin master

Aborting a stash pop in Git

I'm posting here hoping that others my find my answer helpful. I had a similar problem when I tried to do a stash pop on a different branch than the one I had stashed from. On my case I had no files that were uncommitted or in the index but still got into the merge conflicts case (same case as @pid). As others pointed out previously, the failed git stash pop did indeed retain my stash, then A quick git reset HEAD plus going back to my original branch and doing the stash from there did resolve my problem.

C++11 reverse range-based for-loop

Got this example from cppreference. It works with:

GCC 10.1+ with flag -std=c++20

#include <ranges>
#include <iostream>
 
int main()
{
    static constexpr auto il = {3, 1, 4, 1, 5, 9};
 
    std::ranges::reverse_view rv {il};
    for (int i : rv)
        std::cout << i << ' ';
 
    std::cout << '\n';
 
    for(int i : il | std::views::reverse)
        std::cout << i << ' ';
}

How to get process ID of background process?

You need to save the PID of the background process at the time you start it:

foo &
FOO_PID=$!
# do other stuff
kill $FOO_PID

You cannot use job control, since that is an interactive feature and tied to a controlling terminal. A script will not necessarily have a terminal attached at all so job control will not necessarily be available.

JPA With Hibernate Error: [PersistenceUnit: JPA] Unable to build EntityManagerFactory

You don't need both hibernate.cfg.xml and persistence.xml in this case. Have you tried removing hibernate.cfg.xml and mapping everything in persistence.xml only?

But as the other answer also pointed out, this is not okay like this:

@Id
@JoinColumn(name = "categoria") 
private String id;

Didn't you want to use @Column instead?

How to set default Checked in checkbox ReactJS?

You may pass "true" or "" to the checked property of input checkbox. The empty quotes ("") will be understood as false and the item will be unchecked.

let checked = variable === value ? "true" : "";
<input
     className="form-check-input"
    type="checkbox"
    value={variable}
    id={variable}
    name={variable}
    checked={checked}
/>
<label className="form-check-label">{variable}</label>

mysql query result in php variable

Of course there is. Check out mysql_query, and mysql_fetch_row if you use MySQL.
Example from PHP manual:

<?php
$result = mysql_query("SELECT id,email FROM people WHERE id = '42'");
if (!$result) {
    echo 'Could not run query: ' . mysql_error();
    exit;
}
$row = mysql_fetch_row($result);

echo $row[0]; // 42
echo $row[1]; // the email value
?>

Equivalent of waitForVisible/waitForElementPresent in Selenium WebDriver tests using Java?

 
WebElement myDynamicElement = (new WebDriverWait(driver, 10))
.until(ExpectedConditions.presenceOfElementLocated(By.id("myDynamicElement")));

This waits up to 10 seconds before throwing a TimeoutException or if it finds the element will return it in 0 - 10 seconds. WebDriverWait by default calls the ExpectedCondition every 500 milliseconds until it returns successfully. A successful return is for ExpectedCondition type is Boolean return true or not null return value for all other ExpectedCondition types.

WebDriverWait wait = new WebDriverWait(driver, 10);
WebElement element = wait.until(ExpectedConditions.elementToBeClickable(By.id("someid")));

Element is Clickable - it is Displayed and Enabled.

From WebDriver docs: Explicit and Implicit Waits

Sun JSTL taglib declaration fails with "Can not find the tag library descriptor"

To resolve this issue:

  1. The jstl jar should be in your classpath. If you are using maven, add a dependency to jstl in your pom.xml using the snippet provided here. If you are not using maven, download the jstl jar from here and deploy it into your WEB-INF/lib.

  2. Make sure you have the following taglib directive at the top of your jsp:

     <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>

What is the difference between id and class in CSS, and when should I use them?

For more info on this click here.

Example 

<div id="header_id" class="header_class">Text</div>

#header_id {font-color:#fff}
.header_class {font-color:#000}

(Note that CSS uses the prefix # for IDs and . for Classes.)

However color was an HTML 4.01 <font> tag attribute deprecated in HTML 5. In CSS there is no "font-color", the style is color so the above should read:

Example 

<div id="header_id" class="header_class">Text</div>

#header_id {color:#fff}
.header_class {color:#000}

The text would be white.

Why doesn't Git ignore my specified file?

.gitignore will only ignore files that you haven't already added to your repository.

If you did a git add ., and the file got added to the index, .gitignore won't help you. You'll need to do git rm sites/default/settings.php to remove it, and then it will be ignored.

Serialize object to query string in JavaScript/jQuery

Alternatively YUI has http://yuilibrary.com/yui/docs/api/classes/QueryString.html#method_stringify.

For example:

var data = { one: 'first', two: 'second' };
var result = Y.QueryString.stringify(data);

Achieving white opacity effect in html/css

If you can't use rgba due to browser support, and you don't want to include a semi-transparent white PNG, you will have to create two positioned elements. One for the white box, with opacity, and one for the overlaid text, solid.

_x000D_
_x000D_ 
body { background: red; }_x000D_
_x000D_
.box { position: relative; z-index: 1; }_x000D_
.box .back {_x000D_
    position: absolute; z-index: 1;_x000D_
    top: 0; left: 0; width: 100%; height: 100%;_x000D_
    background: white; opacity: 0.75;_x000D_
}_x000D_
.box .text { position: relative; z-index: 2; }_x000D_
_x000D_
body.browser-ie8 .box .back { filter: alpha(opacity=75); }
_x000D_ 
<!--[if lt IE 9]><body class="browser-ie8"><![endif]-->_x000D_
<!--[if gte IE 9]><!--><body><!--<![endif]-->_x000D_
    <div class="box">_x000D_
        <div class="back"></div>_x000D_
        <div class="text">_x000D_
            Lorem ipsum dolor sit amet blah blah boogley woogley oo._x000D_
        </div>_x000D_
    </div>_x000D_
</body>
_x000D_
_x000D_
_x000D_

Convert string in base64 to image and save on filesystem in Python

 
 import base64
 from PIL import Image
 import io
 image = base64.b64decode(str('stringdata'))       
 fileName = 'test.jpeg'

 imagePath = ('D:\\base64toImage\\'+"test.jpeg")
 img = Image.open(io.BytesIO(image))
 img.save(imagePath, 'jpeg')

Append to string variable

 
var str1 = "add";
str1 = str1 + " ";

Hope that helps,

Dan

Specifying content of an iframe instead of the src attribute to a page

You can .write() the content into the iframe document. Example:

<iframe id="FileFrame" src="about:blank"></iframe>

<script type="text/javascript">
   var doc = document.getElementById('FileFrame').contentWindow.document;
   doc.open();
   doc.write('<html><head><title></title></head><body>Hello world.</body></html>');
   doc.close();
</script>

Auto-indent spaces with C in vim?

A lot of vim's features (like autoindent and cindent) are turned off by default. To really see what vim can do for you, you need a decent ~/.vimrc.

A good starter one is in $VIMRUNTIME/vimrc_example.vim. If you want to try it out, use

:source $VIMRUNTIME/vimrc_example.vim

when in vim.

I'd actually suggest just copying the contents to your ~/.vimrc as it's well commented, and a good place to start learning how to use vim. You can do this by

:e $VIMRUNTIME/vimrc_example.vim
:w! ~/.vimrc

This will overwrite your current ~/.vimrc, but if all you have in there is the indent settings Davr suggested, I wouldn't sweat it, as the example vimrc will take care of that for you as well. For a complete walkthrough of the example, and what it does for you, see :help vimrc-intro.

What does it mean by command cd /d %~dp0 in Windows

~dp0 : d=drive, p=path, %0=full path\name of this batch-file.

cd /d %~dp0 will change the path to the same, where the batch file resides.

See for /? or call / for more details about the %~... modifiers.
See cd /? about the /d switch.

Java error: Comparison method violates its general contract

 
        if (card1.getRarity() < card2.getRarity()) {
            return 1;

However, if card2.getRarity() is less than card1.getRarity() you might not return -1.

You similarly miss other cases. I would do this, you can change around depending on your intent:

public int compareTo(Object o) {    
    if(this == o){
        return 0;
    }

    CollectionItem item = (CollectionItem) o;

    Card card1 = CardCache.getInstance().getCard(cardId);
    Card card2 = CardCache.getInstance().getCard(item.getCardId());
    int comp=card1.getSet() - card2.getSet();
    if (comp!=0){
        return comp;
    }
    comp=card1.getRarity() - card2.getRarity();
    if (comp!=0){
        return comp;
    }
    comp=card1.getSet() - card2.getSet();
    if (comp!=0){
        return comp;
    }   
    comp=card1.getId() - card2.getId();
    if (comp!=0){
        return comp;
    }   
    comp=card1.getCardType() - card2.getCardType();

    return comp;

    }
}

Convert a number range to another range, maintaining ratio

I personally use the helper class which supports generics (Swift 3, 4.x compatible)

struct Rescale<Type : BinaryFloatingPoint> {
    typealias RescaleDomain = (lowerBound: Type, upperBound: Type)

    var fromDomain: RescaleDomain
    var toDomain: RescaleDomain

    init(from: RescaleDomain, to: RescaleDomain) {
        self.fromDomain = from
        self.toDomain = to
    }

    func interpolate(_ x: Type ) -> Type {
        return self.toDomain.lowerBound * (1 - x) + self.toDomain.upperBound * x;
    }

    func uninterpolate(_ x: Type) -> Type {
        let b = (self.fromDomain.upperBound - self.fromDomain.lowerBound) != 0 ? self.fromDomain.upperBound - self.fromDomain.lowerBound : 1 / self.fromDomain.upperBound;
        return (x - self.fromDomain.lowerBound) / b
    }

    func rescale(_ x: Type )  -> Type {
        return interpolate( uninterpolate(x) )
    }
}

Ex:

   let rescaler = Rescale<Float>(from: (-1, 1), to: (0, 100))
    
   print(rescaler.rescale(0)) // OUTPUT: 50

Selecting text in an element (akin to highlighting with your mouse)

My particular use-case was selecting a text range inside an editable span element, which, as far as I could see, is not described in any of the answers here.

The main difference is that you have to pass a node of type Text to the Range object, as described in the documentation of Range.setStart():

If the startNode is a Node of type Text, Comment, or CDATASection, then startOffset is the number of characters from the start of startNode. For other Node types, startOffset is the number of child nodes between the start of the startNode.

The Text node is the first child node of a span element, so to get it, access childNodes[0] of the span element. The rest is the same as in most other answers.

Here a code example:

var startIndex = 1;
var endIndex = 5;
var element = document.getElementById("spanId");
var textNode = element.childNodes[0];

var range = document.createRange();
range.setStart(textNode, startIndex);
range.setEnd(textNode, endIndex);

var selection = window.getSelection();
selection.removeAllRanges();
selection.addRange(range);

Other relevant documentation:
Range
Selection
Document.createRange()
Window.getSelection()

php mysqli_connect: authentication method unknown to the client [caching_sha2_password]

If you're on a Mac, here's how to fix it. This is after tons of trial and error. Hope this helps others..

Debugging:

$mysql --verbose --help | grep my.cnf

$ which mysql
/usr/local/bin/mysql

Resolution: nano /usr/local/etc/my.cnf

Add: default-authentication-plugin=mysql_native_password

-------
# Default Homebrew MySQL server config
[mysqld]
# Only allow connections from localhost
bind-address = 127.0.0.1
default-authentication-plugin=mysql_native_password
------

Finally Run: brew services restart mysql

How to rename HTML "browse" button of an input type=file?

The button isn't called the "browse button" — that's just the name your browser gives for it. Browsers are free to implement the file upload control however they like. In Safari, for example, it's called "Choose File" and it's on the opposite side of whatever you're probably using.

You can implement a custom look for the upload control using the technique outlined on QuirksMode, but that goes beyond just changing the button's text.

Design DFA accepting binary strings divisible by a number 'n'

Below, I have written an answer for n equals to 5, but you can apply same approach to draw DFAs for any value of n and 'any positional number system' e.g binary, ternary...

First lean the term 'Complete DFA', A DFA defined on complete domain in d:Q × S?Q is called 'Complete DFA'. In other words we can say; in transition diagram of complete DFA there is no missing edge (e.g. from each state in Q there is one outgoing edge present for every language symbol in S). Note: Sometime we define partial DFA as d ? Q × S?Q (Read: How does “d:Q × S?Q” read in the definition of a DFA).

Design DFA accepting Binary numbers divisible by number 'n':

Step-1: When you divide a number ? by n then reminder can be either 0, 1, ..., (n - 2) or (n - 1). If remainder is 0 that means ? is divisible by n otherwise not. So, in my DFA there will be a state qr that would be corresponding to a remainder value r, where 0 <= r <= (n - 1), and total number of states in DFA is n.
After processing a number string ? over S, the end state is qr implies that ? % n => r (% reminder operator).

In any automata, the purpose of a state is like memory element. A state in an atomata stores some information like fan's switch that can tell whether the fan is in 'off' or in 'on' state. For n = 5, five states in DFA corresponding to five reminder information as follows:

  1. State q0 reached if reminder is 0. State q0 is the final state(accepting state). It is also an initial state.
  2. State q1 reaches if reminder is 1, a non-final state.
  3. State q2 if reminder is 2, a non-final state.
  4. State q3 if reminder is 3, a non-final state.
  5. State q4 if reminder is 4, a non-final state.

Using above information, we can start drawing transition diagram TD of five states as follows:

fig-1
Figure-1

So, 5 states for 5 remainder values. After processing a string ? if end-state becomes q0 that means decimal equivalent of input string is divisible by 5. In above figure q0 is marked final state as two concentric circle.
Additionally, I have defined a transition rule d:(q0, 0)?q0 as a self loop for symbol '0' at state q0, this is because decimal equivalent of any string consist of only '0' is 0 and 0 is a divisible by n.

Step-2: TD above is incomplete; and can only process strings of '0's. Now add some more edges so that it can process subsequent number's strings. Check table below, shows new transition rules those can be added next step:

+-------------------------------------+
¦Number¦Binary¦Remainder(%5)¦End-state¦
+------+------+-------------+---------¦
¦One   ¦1     ¦1            ¦q1       ¦
+------+------+-------------+---------¦
¦Two   ¦10    ¦2            ¦q2       ¦
+------+------+-------------+---------¦
¦Three ¦11    ¦3            ¦q3       ¦
+------+------+-------------+---------¦
¦Four  ¦100   ¦4            ¦q4       ¦
+-------------------------------------+
  1. To process binary string '1' there should be a transition rule d:(q0, 1)?q1
  2. Two:- binary representation is '10', end-state should be q2, and to process '10', we just need to add one more transition rule d:(q1, 0)?q2
    Path: ?(q0)-1?(q1)-0?(q2)
  3. Three:- in binary it is '11', end-state is q3, and we need to add a transition rule d:(q1, 1)?q3
    Path: ?(q0)-1?(q1)-1?(q3)
  4. Four:- in binary '100', end-state is q4. TD already processes prefix string '10' and we just need to add a new transition rule d:(q2, 0)?q4
    Path: ?(q0)-1?(q1)-0?(q2)-0?(q4)

fig-2 Figure-2

Step-3: Five = 101
Above transition diagram in figure-2 is still incomplete and there are many missing edges, for an example no transition is defined for d:(q2, 1)-?. And the rule should be present to process strings like '101'.
Because '101' = 5 is divisible by 5, and to accept '101' I will add d:(q2, 1)?q0 in above figure-2.
Path: ?(q0)-1?(q1)-0?(q2)-1?(q0)
with this new rule, transition diagram becomes as follows:

fig-3 Figure-3

Below in each step I pick next subsequent binary number to add a missing edge until I get TD as a 'complete DFA'.

Step-4: Six = 110.

We can process '11' in present TD in figure-3 as: ?(q0)-11?(q3) -0?(?). Because 6 % 5 = 1 this means to add one rule d:(q3, 0)?q1.

fig-4 Figure-4

Step-5: Seven = 111

+--------------------------------------------------------------+
¦Number¦Binary¦Remainder(%5)¦End-state¦ Path       ¦ Add       ¦
+------+------+-------------+---------+------------+-----------¦
¦Seven ¦111   ¦7 % 5 = 2    ¦q2       ¦ q0-11?q3   ¦ q3-1?q2    ¦
+--------------------------------------------------------------+

fig-5 Figure-5

Step-6: Eight = 1000

+----------------------------------------------------------+
¦Number¦Binary¦Remainder(%5)¦End-state¦ Path     ¦ Add     ¦
+------+------+-------------+---------+----------+---------¦
¦Eight ¦1000  ¦8 % 5 = 3    ¦q3       ¦q0-100?q4 ¦ q4-0?q3  ¦
+----------------------------------------------------------+

fig-6 Figure-6

Step-7: Nine = 1001 

+----------------------------------------------------------+
¦Number¦Binary¦Remainder(%5)¦End-state¦ Path     ¦ Add     ¦
+------+------+-------------+---------+----------+---------¦
¦Nine  ¦1001  ¦9 % 5 = 4    ¦q4       ¦q0-100?q4 ¦ q4-1?q4  ¦
+----------------------------------------------------------+

fig-7 Figure-7

In TD-7, total number of edges are 10 == Q × S = 5 × 2. And it is a complete DFA that can accept all possible binary strings those decimal equivalent is divisible by 5.

Design DFA accepting Ternary numbers divisible by number n:

Step-1 Exactly same as for binary, use figure-1.

Step-2 Add Zero, One, Two

+------------------------------------------------------+
¦Decimal¦Ternary¦Remainder(%5)¦End-state¦   Add        ¦
+-------+-------+-------------+---------+--------------¦
¦Zero   ¦0      ¦0            ¦q0       ¦ d:(q0,0)?q0  ¦
+-------+-------+-------------+---------+--------------¦
¦One    ¦1      ¦1            ¦q1       ¦ d:(q0,1)?q1  ¦
+-------+-------+-------------+---------+--------------¦
¦Two    ¦2      ¦2            ¦q2       ¦ d:(q0,2)?q3  ¦
+------------------------------------------------------+

fig-8
Figure-8

Step-3 Add Three, Four, Five 

+-----------------------------------------------------+
¦Decimal¦Ternary¦Remainder(%5)¦End-state¦  Add        ¦
+-------+-------+-------------+---------+-------------¦
¦Three  ¦10     ¦3            ¦q3       ¦ d:(q1,0)?q3 ¦
+-------+-------+-------------+---------+-------------¦
¦Four   ¦11     ¦4            ¦q4       ¦ d:(q1,1)?q4 ¦
+-------+-------+-------------+---------+-------------¦
¦Five   ¦12     ¦0            ¦q0       ¦ d:(q1,2)?q0 ¦
+-----------------------------------------------------+

fig-9
Figure-9

Step-4 Add Six, Seven, Eight

+-----------------------------------------------------+
¦Decimal¦Ternary¦Remainder(%5)¦End-state¦  Add        ¦
+-------+-------+-------------+---------+-------------¦
¦Six    ¦20     ¦1            ¦q1       ¦ d:(q2,0)?q1 ¦
+-------+-------+-------------+---------+-------------¦
¦Seven  ¦21     ¦2            ¦q2       ¦ d:(q2,1)?q2 ¦
+-------+-------+-------------+---------+-------------¦
¦Eight  ¦22     ¦3            ¦q3       ¦ d:(q2,2)?q3 ¦
+-----------------------------------------------------+

fig-10
Figure-10

Step-5 Add Nine, Ten, Eleven

+-----------------------------------------------------+
¦Decimal¦Ternary¦Remainder(%5)¦End-state¦  Add        ¦
+-------+-------+-------------+---------+-------------¦
¦Nine   ¦100    ¦4            ¦q4       ¦ d:(q3,0)?q4 ¦
+-------+-------+-------------+---------+-------------¦
¦Ten    ¦101    ¦0            ¦q0       ¦ d:(q3,1)?q0 ¦
+-------+-------+-------------+---------+-------------¦
¦Eleven ¦102    ¦1            ¦q1       ¦ d:(q3,2)?q1 ¦
+-----------------------------------------------------+

fig-11
Figure-11

Step-6 Add Twelve, Thirteen, Fourteen

+------------------------------------------------------+
¦Decimal ¦Ternary¦Remainder(%5)¦End-state¦  Add        ¦
+--------+-------+-------------+---------+-------------¦
¦Twelve  ¦110    ¦2            ¦q2       ¦ d:(q4,0)?q2 ¦
+--------+-------+-------------+---------+-------------¦
¦Thirteen¦111    ¦3            ¦q3       ¦ d:(q4,1)?q3 ¦
+--------+-------+-------------+---------+-------------¦
¦Fourteen¦112    ¦4            ¦q4       ¦ d:(q4,2)?q4 ¦
+------------------------------------------------------+

fig-12
Figure-12

Total number of edges in transition diagram figure-12 are 15 = Q × S = 5 * 3 (a complete DFA). And this DFA can accept all strings consist over {0, 1, 2} those decimal equivalent is divisible by 5.
If you notice at each step, in table there are three entries because at each step I add all possible outgoing edge from a state to make a complete DFA (and I add an edge so that qr state gets for remainder is r)!

To add further, remember union of two regular languages are also a regular. If you need to design a DFA that accepts binary strings those decimal equivalent is either divisible by 3 or 5, then draw two separate DFAs for divisible by 3 and 5 then union both DFAs to construct target DFA (for 1 <= n <= 10 your have to union 10 DFAs).

If you are asked to draw DFA that accepts binary strings such that decimal equivalent is divisible by 5 and 3 both then you are looking for DFA of divisible by 15 ( but what about 6 and 8?).

Note: DFAs drawn with this technique will be minimized DFA only when there is no common factor between number n and base e.g. there is no between 5 and 2 in first example, or between 5 and 3 in second example, hence both DFAs constructed above are minimized DFAs. If you are interested to read further about possible mini states for number n and base b read paper: Divisibility and State Complexity.

below I have added a Python script, I written it for fun while learning Python library pygraphviz. I am adding it I hope it can be helpful for someone in someway.

Design DFA for base 'b' number strings divisible by number 'n':

So we can apply above trick to draw DFA to recognize number strings in any base 'b' those are divisible a given number 'n'. In that DFA total number of states will be n (for n remainders) and number of edges should be equal to 'b' * 'n' — that is complete DFA: 'b' = number of symbols in language of DFA and 'n' = number of states.

Using above trick, below I have written a Python Script to Draw DFA for input base and number. In script, function divided_by_N populates DFA's transition rules in base * number steps. In each step-num, I convert num into number string num_s using function baseN(). To avoid processing each number string, I have used a temporary data-structure lookup_table. In each step, end-state for number string num_s is evaluated and stored in lookup_table to use in next step.

For transition graph of DFA, I have written a function draw_transition_graph using Pygraphviz library (very easy to use). To use this script you need to install graphviz. To add colorful edges in transition diagram, I randomly generates color codes for each symbol get_color_dict function.

#!/usr/bin/env python
import pygraphviz as pgv
from pprint import pprint
from random import choice as rchoice

def baseN(n, b, syms="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"):
    """ converts a number `n` into base `b` string """
    return ((n == 0) and syms[0]) or (
        baseN(n//b, b, syms).lstrip(syms[0]) + syms[n % b])

def divided_by_N(number, base):
    """
    constructs DFA that accepts given `base` number strings
    those are divisible by a given `number`
    """
    ACCEPTING_STATE = START_STATE = '0'
    SYMBOL_0 = '0'
    dfa = {
        str(from_state): {
            str(symbol): 'to_state' for symbol in range(base)
        }
        for from_state in range(number)
    }
    dfa[START_STATE][SYMBOL_0] = ACCEPTING_STATE
    # `lookup_table` keeps track: 'number string' -->[dfa]--> 'end_state'
    lookup_table = { SYMBOL_0: ACCEPTING_STATE }.setdefault
    for num in range(number * base):
        end_state = str(num % number)
        num_s = baseN(num, base)
        before_end_state = lookup_table(num_s[:-1], START_STATE)
        dfa[before_end_state][num_s[-1]] = end_state
        lookup_table(num_s, end_state)
    return dfa

def symcolrhexcodes(symbols):
    """
    returns dict of color codes mapped with alphabets symbol in symbols
    """
    return {
        symbol: '#'+''.join([
            rchoice("8A6C2B590D1F4E37") for _ in "FFFFFF"
        ])
        for symbol in symbols
    }

def draw_transition_graph(dfa, filename="filename"):
    ACCEPTING_STATE = START_STATE = '0'
    colors = symcolrhexcodes(dfa[START_STATE].keys())
    # draw transition graph
    tg = pgv.AGraph(strict=False, directed=True, decorate=True)
    for from_state in dfa:
        for symbol, to_state in dfa[from_state].iteritems():
            tg.add_edge("Q%s"%from_state, "Q%s"%to_state,
                        label=symbol, color=colors[symbol],
                        fontcolor=colors[symbol])

    # add intial edge from an invisible node!
    tg.add_node('null', shape='plaintext', label='start')
    tg.add_edge('null', "Q%s"%START_STATE,)

    # make end acception state as 'doublecircle'
    tg.get_node("Q%s"%ACCEPTING_STATE).attr['shape'] = 'doublecircle'
    tg.draw(filename, prog='circo')
    tg.close()

def print_transition_table(dfa):
    print("DFA accepting number string in base '%(base)s' "
            "those are divisible by '%(number)s':" % {
                'base': len(dfa['0']),
                'number': len(dfa),})
    pprint(dfa)

if __name__ == "__main__":
    number = input ("Enter NUMBER: ")
    base = input ("Enter BASE of number system: ")
    dfa = divided_by_N(number, base)

    print_transition_table(dfa)
    draw_transition_graph(dfa)

Execute it:

~/study/divide-5/script$ python script.py 
Enter NUMBER: 5
Enter BASE of number system: 4
DFA accepting number string in base '4' those are divisible by '5':
{'0': {'0': '0', '1': '1', '2': '2', '3': '3'},
 '1': {'0': '4', '1': '0', '2': '1', '3': '2'},
 '2': {'0': '3', '1': '4', '2': '0', '3': '1'},
 '3': {'0': '2', '1': '3', '2': '4', '3': '0'},
 '4': {'0': '1', '1': '2', '2': '3', '3': '4'}}
~/study/divide-5/script$ ls
script.py filename.png
~/study/divide-5/script$ display filename

Output:

base_4_divided_5_best
DFA accepting number strings in base 4 those are divisible by 5

Similarly, enter base = 4 and number = 7 to generate - dfa accepting number string in base '4' those are divisible by '7'
Btw, try changing filename to .png or .jpeg.

References those I use to write this script:
➊ Function baseN from "convert integer to a string in a given numeric base in python"
➋ To install "pygraphviz": "Python does not see pygraphviz"
➌ To learn use of Pygraphviz: "Python-FSM"
➍ To generate random hex color codes for each language symbol: "How would I make a random hexdigit code generator using .join and for loops?"

Update Row if it Exists Else Insert Logic with Entity Framework

The magic happens when calling SaveChanges() and depends on the current EntityState. If the entity has an EntityState.Added, it will be added to the database, if it has an EntityState.Modified, it will be updated in the database. So you can implement an InsertOrUpdate() method as follows:

public void InsertOrUpdate(Blog blog) 
{ 
    using (var context = new BloggingContext()) 
    { 
        context.Entry(blog).State = blog.BlogId == 0 ? 
                                   EntityState.Added : 
                                   EntityState.Modified; 

        context.SaveChanges(); 
    } 
}

More about EntityState

If you can't check on Id = 0 to determine if it's a new entity or not, check the answer of Ladislav Mrnka.

What is a provisioning profile used for when developing iPhone applications?

You need it to install development iPhone applications on development devices.

Here's how to create one, and the reference for this answer:
http://www.wikihow.com/Create-a-Provisioning-Profile-for-iPhone

Another link: http://iphone.timefold.com/provisioning.html

Check if the file exists using VBA

Correction to fileExists from @UberNubIsTrue :

Function fileExists(s_directory As String, s_fileName As String) As Boolean

  Dim obj_fso As Object, obj_dir As Object, obj_file As Object
  Dim ret As Boolean
   Set obj_fso = CreateObject("Scripting.FileSystemObject")
   Set obj_dir = obj_fso.GetFolder(s_directory)
   ret = False
   For Each obj_file In obj_dir.Files
     If obj_fso.fileExists(s_directory & "\" & s_fileName) = True Then
        ret = True
        Exit For
      End If
   Next

   Set obj_fso = Nothing
   Set obj_dir = Nothing
   fileExists = ret

 End Function

EDIT: shortened version

' Check if a file exists
Function fileExists(s_directory As String, s_fileName As String) As Boolean

    Dim obj_fso As Object

    Set obj_fso = CreateObject("Scripting.FileSystemObject")
    fileExists = obj_fso.fileExists(s_directory & "\" & s_fileName)

End Function

What is the difference between "SMS Push" and "WAP Push"?

An SMS Push is a message to tell the terminal to initiate the session. This happens because you can't initiate an IP session simply because you don't know the IP Adress of the mobile terminal. Mostly used to send a few lines of data to end recipient, to the effect of sending information, or reminding of events.

WAP Push is an SMS within the header of which is included a link to a WAP address. On receiving a WAP Push, the compatible mobile handset automatically gives the user the option to access the WAP content on his handset. The WAP Push directs the end-user to a WAP address where content is stored ready for viewing or downloading onto the handset. This wap address may be a page or a WAP site.

The user may “take action” by using a developer-defined soft-key to immediately activate an application to accomplish a specific task, such as downloading a picture, making a purchase, or responding to a marketing offer.

Triggering change detection manually in Angular

In Angular 2+, try the @Input decorator

It allows for some nice property binding between parent and child components.

First create a global variable in the parent to hold the object/property that will be passed to the child.

Next create a global variable in the child to hold the object/property passed from the parent.

Then in the parent html, where the child template is used, add square brackets notation with the name of the child variable, then set it equal to the name of the parent variable. Example:

<child-component-template [childVariable] = parentVariable>
</child-component-template>

Finally, where the child property is defined in the child component, add the Input decorator:

@Input()
public childVariable: any

When your parent variable is updated, it should pass the updates to the child component, which will update its html.

Also, to trigger a function in the child component, take a look at ngOnChanges.

How to create custom spinner like border around the spinner with down triangle on the right side?

You can achieve the following by using a single line in your spinner declaration in XML: enter image description here

Just add this: style="@android:style/Widget.Holo.Light.Spinner"

This is a default generated style in android. It doesn't contain borders around it though. For that you'd better search something on google.

Hope this helps.

UPDATE: AFter a lot of digging I got something which works well for introducing border around spinner.

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:bottom="8dp"
        android:top="8dp">
        <shape>
            <solid android:color="@android:color/white" />
            <corners android:radius="4dp" />
            <stroke
                android:width="2dp"
                android:color="#9E9E9E" />
            <padding
                android:bottom="16dp"
                android:left="8dp"
                android:right="16dp"
                android:top="16dp" />
        </shape>
    </item>
</layer-list>

Place this in the drawable folder and use it as a background for spinner. Like this:

<RelativeLayout
        android:id="@+id/speaker_relative_layout"
        android:layout_width="0dp"
        android:layout_height="70dp"
        android:layout_marginEnd="8dp"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="16dp"
        android:background="@drawable/spinner_style"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <Spinner
            android:id="@+id/select_speaker_spinner"
            style="@style/Widget.AppCompat.DropDownItem.Spinner"
            android:layout_width="match_parent"
            android:layout_height="70dp"
            android:entries="@array/select_speaker_spinner_array"
            android:spinnerMode="dialog" />

    </RelativeLayout>

Auto-increment on partial primary key with Entity Framework Core

Specifying the column type as serial for PostgreSQL to generate the id.

[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
[Column(Order=1, TypeName="serial")]
public int ID { get; set; }

https://www.postgresql.org/docs/current/static/datatype-numeric.html#DATATYPE-SERIAL

Why does JPA have a @Transient annotation?

Because they have different meanings. The @Transient annotation tells the JPA provider to not persist any (non-transient) attribute. The other tells the serialization framework to not serialize an attribute. You might want to have a @Transient property and still serialize it.

What is default color for text in textview?

Actually the color TextView is: 

android:textColor="@android:color/tab_indicator_text"

or

#808080

Autowiring fails: Not an managed Type

Refering to Oliver Gierke's hint:

When the manipulation of the persistance.xml does the trick, then you created a normal java-class instead of a entity-class.

When creating a new entity-class then the entry in the persistance.xml should be set by Netbeans (in my case).

But as mentioned by Oliver Gierke you can add the entry later to the persistance.xml (if you created a normal java-class).

Entity Framework: One Database, Multiple DbContexts. Is this a bad idea?

I want to share a case, where I think the possibility of having multiple DBContexts in the same database makes good sense.

I have a solution with two database. One is for domain data except user information. The other is solely for user information. This division is primarily driven by the EU General Data Protection Regulation. By having two databases, I can freely move the domain data around (e.g. from Azure to my development environment) as long as the user data stays in one secure place.

Now for the user database I have implemented two schemas through EF. One is the default one provided by the AspNet Identity framework. The other is our own implementing anything else user related. I prefer this solution over extending the ApsNet schema, because I can easily handle future changes to AspNet Identity and at the same time the separation makes it clear to the programmers, that "our own user information" goes in the specific user schema we have defined.

Length of array in function argument

length of an array(type int) with sizeof: sizeof(array)/sizeof(int)

how to reset <input type = "file">

I use for vuejs 

   <input
          type="file"
          ref="fileref"
          @change="onChange"/>

this.$refs.fileref.value = ''

Access denied for user 'root'@'localhost' (using password: YES) (Mysql::Error)

Add a user option in msyql.

GRANT PROXY ON ''@'' TO 'root'@'localhost' WITH GRANT OPTION;

and this link will be useful.

Is this the right way to clean-up Fragment back stack when leaving a deeply nested stack?

As written in How to pop fragment off backstack and by LarsH here, we can pop several fragments from top down to specifical tag (together with the tagged fragment) using this method:

fragmentManager?.popBackStack ("frag", FragmentManager.POP_BACK_STACK_INCLUSIVE);

Substitute "frag" with your fragment's tag. Remember that first we should add the fragment to backstack with:

fragmentTransaction.addToBackStack("frag")

If we add fragments with addToBackStack(null), we won't pop fragments that way.

Python read in string from file and split it into values

 
>>> [[int(i) for i in line.strip().split(',')] for line in open('input.txt').readlines()]
[[995957, 16833579], [995959, 16777241], [995960, 16829368], [995961, 50431654]]

jquery change button color onclick

 
$('input[type="submit"]').click(function(){
$(this).css('color','red');
});

Use class, Demo:- http://jsfiddle.net/BX6Df/

   $('input[type="submit"]').click(function(){
          $(this).addClass('red');
});

if you want to toggle the color each click, you can try this:- http://jsfiddle.net/SMNks/

$('input[type="submit"]').click(function(){
  $(this).toggleClass('red');
});


.red
{
    background-color:red;
}

Updated answer for your comment.

http://jsfiddle.net/H2Xhw/

$('input[type="submit"]').click(function(){
    $('input[type="submit"].red').removeClass('red')
        $(this).addClass('red');
});

How to create a date object from string in javascript

Always, for any issue regarding the JavaScript spec in practical, I will highly recommend the Mozilla Developer Network, and their JavaScript reference.

As it states in the topic of the Date object about the argument variant you use:

new Date(year, month, day [, hour, minute, second, millisecond ])

And about the months parameter:

month Integer value representing the month, beginning with 0 for January to 11 for December.

Clearly, then, you should use the month number 10 for November.

P.S.: The reason why I recommend the MDN is the correctness, good explanation of things, examples, and browser compatibility chart.

How can I install a .ipa file to my iPhone simulator

You can run the application file of project in simulator - not .ipa file.

You can get it from:

Libraries-->Applicationsupport-->iphone simulator-->4.3(its ur simulator version)-->applications-->then u can see many files like 0CD04F.... find out your application file through open it.

You can copy the file to your system(which system simulator u need run ) location Libraries-->Applicationsupport-->iphone simulator-->4.3(its your simulator version)-->applications-->

Then open the simulator 4.3 (its your simulator version where you pasted). You can see the application installed there.

Getting from other people:

Please tell them to find out Libraries-->Applicationsupport-->iphone simulator-->4.3(its ur simulator version)-->applications-->then you can see many files like 0CD04F.... from their system and receive that file from them.

After they have got the file, please copy and paste the file in to your system `Libraries-->Applicationsupport-->iphone simulator-->4.3(its your simulator version)-->applications-->(paste the file here).

Then you can see the app is installed in your system simulator and you can run it after clicking the file.

What is this weird colon-member (" : ") syntax in the constructor?

there is another 'benefit'

if the member variable type does not support null initialization or if its a reference (which cannot be null initialized) then you have no choice but to supply an initialization list

ps command doesn't work in docker container

In case you can't install the procps package (don't have proper permissions) you can use /proc directory.

The first few directories (named as numbers) are PIDs of your processes. Inside directories, you can find additional information useful to decipher which process is connected to each PID. For example, you can use the cat command to view "cmdline" file to check which process is connected to PID.

$ ls /proc
1 10 11 ...

$ ls -1 /proc/22
attr
autogroup
auxv
cgroup
clear_refs
cmdline
...

$ cat /proc/22/cmdline 
/bin/sh

Android Studio - Failed to apply plugin [id 'com.android.application']

you just need to change your project.gradle file. And sync your Gradle. 

dependencies {
 classpath 'com.android.tools.build:gradle:2.2.2'
}

Know relationships between all the tables of database in SQL Server

This stored procedure will provide you with a hierarchical tree of relationship. Based on this article from Technet. It will also optionally provide you a query for reading or deleting all the related data. 

IF OBJECT_ID('GetForeignKeyRelations','P') IS NOT NULL 
    DROP PROC GetForeignKeyRelations 
GO 

CREATE PROC GetForeignKeyRelations 
@Schemaname Sysname = 'dbo' 
,@Tablename Sysname 
,@WhereClause NVARCHAR(2000) = '' 
,@GenerateDeleteScripts bit  = 0  
,@GenerateSelectScripts bit  = 0 

AS 

SET NOCOUNT ON 

DECLARE @fkeytbl TABLE 
( 
ReferencingObjectid        int NULL 
,ReferencingSchemaname  Sysname NULL 
,ReferencingTablename   Sysname NULL  
,ReferencingColumnname  Sysname NULL 
,PrimarykeyObjectid     int  NULL 
,PrimarykeySchemaname   Sysname NULL 
,PrimarykeyTablename    Sysname NULL 
,PrimarykeyColumnname   Sysname NULL 
,Hierarchy              varchar(max) NULL 
,level                  int NULL 
,rnk                    varchar(max) NULL 
,Processed                bit default 0  NULL 
); 



 WITH fkey (ReferencingObjectid,ReferencingSchemaname,ReferencingTablename,ReferencingColumnname 
            ,PrimarykeyObjectid,PrimarykeySchemaname,PrimarykeyTablename,PrimarykeyColumnname,Hierarchy,level,rnk) 
    AS 
    ( 
        SELECT                   
                               soc.object_id 
                              ,scc.name 
                              ,soc.name 
                              ,convert(sysname,null) 
                              ,convert(int,null) 
                              ,convert(sysname,null) 
                              ,convert(sysname,null) 
                              ,convert(sysname,null) 
                              ,CONVERT(VARCHAR(MAX), scc.name + '.' + soc.name  ) as Hierarchy 
                              ,0 as level 
                              ,rnk=convert(varchar(max),soc.object_id) 
        FROM SYS.objects soc 
        JOIN sys.schemas scc 
          ON soc.schema_id = scc.schema_id 
       WHERE scc.name =@Schemaname 
         AND soc.name =@Tablename 
      UNION ALL 
      SELECT                   sop.object_id 
                              ,scp.name 
                              ,sop.name 
                              ,socp.name 
                              ,soc.object_id 
                              ,scc.name 
                              ,soc.name 
                              ,socc.name 
                              ,CONVERT(VARCHAR(MAX), f.Hierarchy + ' --> ' + scp.name + '.' + sop.name ) as Hierarchy 
                              ,f.level+1 as level 
                              ,rnk=f.rnk + '-' + convert(varchar(max),sop.object_id) 
        FROM SYS.foreign_key_columns sfc 
        JOIN Sys.Objects sop 
          ON sfc.parent_object_id = sop.object_id 
        JOIN SYS.columns socp 
          ON socp.object_id = sop.object_id 
         AND socp.column_id = sfc.parent_column_id 
        JOIN sys.schemas scp 
          ON sop.schema_id = scp.schema_id 
        JOIN SYS.objects soc 
          ON sfc.referenced_object_id = soc.object_id 
        JOIN SYS.columns socc 
          ON socc.object_id = soc.object_id 
         AND socc.column_id = sfc.referenced_column_id 
        JOIN sys.schemas scc 
          ON soc.schema_id = scc.schema_id 
        JOIN fkey f 
          ON f.ReferencingObjectid = sfc.referenced_object_id 
        WHERE ISNULL(f.PrimarykeyObjectid,0) <> f.ReferencingObjectid 
      ) 

     INSERT INTO @fkeytbl 
     (ReferencingObjectid,ReferencingSchemaname,ReferencingTablename,ReferencingColumnname 
            ,PrimarykeyObjectid,PrimarykeySchemaname,PrimarykeyTablename,PrimarykeyColumnname,Hierarchy,level,rnk) 
     SELECT ReferencingObjectid,ReferencingSchemaname,ReferencingTablename,ReferencingColumnname 
            ,PrimarykeyObjectid,PrimarykeySchemaname,PrimarykeyTablename,PrimarykeyColumnname,Hierarchy,level,rnk 
       FROM fkey 

        SELECT F.Relationshiptree 
         FROM 
        ( 
        SELECT DISTINCT Replicate('------',Level) + CASE LEVEL WHEN 0 THEN '' ELSE '>' END +  ReferencingSchemaname + '.' + ReferencingTablename 'Relationshiptree' 
               ,RNK 
          FROM @fkeytbl 
          ) F 
        ORDER BY F.rnk ASC 

------------------------------------------------------------------------------------------------------------------------------- 
-- Generate the Delete / Select script 
------------------------------------------------------------------------------------------------------------------------------- 

    DECLARE @Sql VARCHAR(MAX) 
    DECLARE @RnkSql VARCHAR(MAX) 

    DECLARE @Jointables TABLE 
    ( 
    ID INT IDENTITY 
    ,Object_id int 
    ) 

    DECLARE @ProcessTablename SYSNAME 
    DECLARE @ProcessSchemaName SYSNAME 

    DECLARE @JoinConditionSQL VARCHAR(MAX) 
    DECLARE @Rnk VARCHAR(MAX) 
    DECLARE @OldTablename SYSNAME 

    IF @GenerateDeleteScripts = 1 or @GenerateSelectScripts = 1  
    BEGIN 

          WHILE EXISTS ( SELECT 1 
                           FROM @fkeytbl 
                          WHERE Processed = 0 
                            AND level > 0 ) 
          BEGIN 

            SELECT @ProcessTablename = '' 
            SELECT @Sql                 = '' 
            SELECT @JoinConditionSQL = '' 
            SELECT @OldTablename     = '' 


            SELECT TOP 1 @ProcessTablename = ReferencingTablename 
                  ,@ProcessSchemaName  = ReferencingSchemaname 
                  ,@Rnk = RNK  
              FROM @fkeytbl 
             WHERE Processed = 0 
              AND level > 0  
             ORDER BY level DESC 


            SELECT @RnkSql ='SELECT ' + REPLACE (@rnk,'-',' UNION ALL SELECT ')  

            DELETE FROM @Jointables 

            INSERT INTO @Jointables 
            EXEC(@RnkSql) 

            IF @GenerateDeleteScripts = 1 
                SELECT @Sql = 'DELETE [' + @ProcessSchemaName + '].[' + @ProcessTablename + ']' + CHAR(10) + ' FROM [' + @ProcessSchemaName + '].[' + @ProcessTablename + ']' + CHAR(10) 

            IF @GenerateSelectScripts = 1 
                SELECT @Sql = 'SELECT  [' + @ProcessSchemaName + '].[' + @ProcessTablename + '].*' + CHAR(10) + ' FROM [' + @ProcessSchemaName + '].[' + @ProcessTablename + ']' + CHAR(10) 

            SELECT @JoinConditionSQL = @JoinConditionSQL  
                                           + CASE  
                                             WHEN @OldTablename <> f.PrimarykeyTablename THEN  'JOIN ['  + f.PrimarykeySchemaname  + '].[' + f.PrimarykeyTablename + '] ' + CHAR(10) + ' ON ' 
                                             ELSE ' AND '  
                                             END 
                                           + ' ['  + f.PrimarykeySchemaname  + '].[' + f.PrimarykeyTablename + '].[' + f.PrimarykeyColumnname + '] =  ['  + f.ReferencingSchemaname  + '].[' + f.ReferencingTablename + '].[' + f.ReferencingColumnname + ']' + CHAR(10)  
                     , @OldTablename = CASE  
                                         WHEN @OldTablename <> f.PrimarykeyTablename THEN  f.PrimarykeyTablename 
                                         ELSE @OldTablename 
                                         END 

                  FROM @fkeytbl f 
                  JOIN @Jointables j 
                    ON f.Referencingobjectid  = j.Object_id 
                 WHERE charindex(f.rnk + '-',@Rnk + '-') <> 0 
                   AND F.level > 0 
                 ORDER BY J.ID DESC 

            SELECT @Sql = @Sql +  @JoinConditionSQL 

            IF LTRIM(RTRIM(@WhereClause)) <> ''  
                SELECT @Sql = @Sql + ' WHERE (' + @WhereClause + ')' 

            PRINT @SQL 
            PRINT CHAR(10) 

            UPDATE @fkeytbl 
               SET Processed = 1 
             WHERE ReferencingTablename = @ProcessTablename 
               AND rnk = @Rnk 

          END 

          IF @GenerateDeleteScripts = 1 
            SELECT @Sql = 'DELETE FROM [' + @Schemaname + '].[' + @Tablename + ']' 

          IF @GenerateSelectScripts = 1 
            SELECT @Sql = 'SELECT * FROM [' + @Schemaname + '].[' + @Tablename + ']' 

          IF LTRIM(RTRIM(@WhereClause)) <> ''  
                SELECT @Sql = @Sql  + ' WHERE ' + @WhereClause 

         PRINT @SQL 
     END 

SET NOCOUNT OFF 


go

Separation of business logic and data access in django

I'm mostly agree with chosen answer (https://stackoverflow.com/a/12857584/871392), but want to add option in Making Queries section.

One can define QuerySet classes for models for make filter queries and so on. After that you can proxy this queryset class for model's manager, like build-in Manager and QuerySet classes do.

Although, if you had to query several data models to get one domain model, it seems more reasonable to me to put this in separate module like suggested before.

matplotlib colorbar in each subplot

In plt.colorbar(z1_plot,cax=ax1), use ax= instead of cax=, i.e. plt.colorbar(z1_plot,ax=ax1)

How to make an Asynchronous Method return a value?

Use a BackgroundWorker. It will allow you to get callbacks on completion and allow you to track progress. You can set the Result value on the event arguments to the resulting value.

    public void UseBackgroundWorker()
    {
        var worker = new BackgroundWorker();
        worker.DoWork += DoWork;
        worker.RunWorkerCompleted += WorkDone;
        worker.RunWorkerAsync("input");
    }

    public void DoWork(object sender, DoWorkEventArgs e)
    {
        e.Result = e.Argument.Equals("input");
        Thread.Sleep(1000);
    }

    public void WorkDone(object sender, RunWorkerCompletedEventArgs e)
    {
        var result = (bool) e.Result;
    }

How to create materialized views in SQL Server?

You might need a bit more background on what a Materialized View actually is. In Oracle these are an object that consists of a number of elements when you try to build it elsewhere.

An MVIEW is essentially a snapshot of data from another source. Unlike a view the data is not found when you query the view it is stored locally in a form of table. The MVIEW is refreshed using a background procedure that kicks off at regular intervals or when the source data changes. Oracle allows for full or partial refreshes.

In SQL Server, I would use the following to create a basic MVIEW to (complete) refresh regularly.

First, a view. This should be easy for most since views are quite common in any database Next, a table. This should be identical to the view in columns and data. This will store a snapshot of the view data. Then, a procedure that truncates the table, and reloads it based on the current data in the view. Finally, a job that triggers the procedure to start it's work.

Everything else is experimentation.

json_encode sparse PHP array as JSON array, not JSON object

Try this,

<?php
$arr1=array('result1'=>'abcd','result2'=>'efg'); 
$arr2=array('result1'=>'hijk','result2'=>'lmn'); 
$arr3=array($arr1,$arr2); 
print (json_encode($arr3)); 
?>

How to add http:// if it doesn't exist in the URL

A modified version of @nickf code:

function addhttp($url) {
    if (!preg_match("~^(?:f|ht)tps?://~i", $url)) {
        $url = "http://" . $url;
    }
    return $url;
}

Recognizes ftp://, ftps://, http:// and https:// in a case insensitive way.

SQL Switch/Case in 'where' clause

Try this:

WHERE (
    @smartLocationType IS NULL 
    OR account_location = (
         CASE
            WHEN @smartLocationType IS NOT NULL 
                 THEN @smartLocationType
            ELSE account_location 
         END
    )
)

How do I fix a NoSuchMethodError?

Above answer explains very well ..just to add one thing If you are using using eclipse use ctrl+shift+T and enter package structure of class (e.g. : gateway.smpp.PDUEventListener ), you will find all jars/projects where it's present. Remove unnecessary jars from classpath or add above in class path. Now it will pick up correct one.

Detect when an HTML5 video finishes

Have a look at this Everything You Need to Know About HTML5 Video and Audio post at the Opera Dev site under the "I want to roll my own controls" section.

This is the pertinent section:

<video src="video.ogv">
     video not supported
</video>

then you can use:

<script>
    var video = document.getElementsByTagName('video')[0];

    video.onended = function(e) {
      /*Do things here!*/
    };
</script>

onended is a HTML5 standard event on all media elements, see the HTML5 media element (video/audio) events documentation.

How to convert string to boolean php

 
function stringToBool($string){
    return ( mb_strtoupper( trim( $string)) === mb_strtoupper ("true")) ? TRUE : FALSE;
}

or

function stringToBool($string) {
    return filter_var($string, FILTER_VALIDATE_BOOLEAN);
}

Npm Please try using this command again as root/administrator
  1. Close the IDE
  2. Close the node terminals running ng serve or npm start
  3. Go to your project folder/node_modules and see you if can find the package that you are trying to install
  4. If you find the package you are searching then delete package folder
  5. In case, this is your 1st npm install then skip step 4 and delete everything inside the node_modules. If you don't find node_modules then create one folder in your project.
  6. Open the terminal in admin mode and do npm install.

That should fix the issue hopefully

Invalid use side-effecting operator Insert within a function

Functions cannot be used to modify base table information, use a stored procedure.

how to set ulimit / file descriptor on docker container the image tag is phusion/baseimage-docker

The docker run command has a --ulimit flag you can use this flag to set the open file limit in your docker container.

Run the following command when spinning up your container to set the open file limit.

docker run --ulimit nofile=<softlimit>:<hardlimit> the first value before the colon indicates the soft file limit and the value after the colon indicates the hard file limit. you can verify this by running your container in interactive mode and executing the following command in your containers shell ulimit -n

PS: check out this blog post for more clarity

What is the reason for a red exclamation mark next to my project in Eclipse?

Go to Project -> right click -> properties -> Java Build Path -> Libraries

Delete all the JARs which have red cross symbol on the icon.

Resolved.

Using OR operator in a jquery if statement

The logical OR '||' automatically short circuits if it meets a true condition once.

false || false || true || false = true, stops at second condition.

On the other hand, the logical AND '&&' automatically short circuits if it meets a false condition once.

false && true && true && true = false, stops at first condition.

Best practices for styling HTML emails

I've fought the HTML email battle before. Here are some of my tips about styling for maximum compatibility between email clients.

  • Inline styles are you best friend. Absolutely don't link style sheets and do not use a <style> tag (GMail, for example, strips that tag and all it's contents).

  • Against your better judgement, use and abuse tables. <div>s just won't cut it (especially in Outlook).

  • Don't use background images, they're spotty and will annoy you.

  • Remember that some email clients will automatically transform typed out hyperlinks into links (if you don't anchor <a> them yourself). This can sometimes achieve negative effects (say if you're putting a style on each of the hyperlinks to appear a different color).

  • Be careful hyperlinking an actual link with something different. For example, don't type out http://www.google.com and then link it to https://gmail.com/. Some clients will flag the message as Spam or Junk.

  • Save your images in as few colors as possible to save on size.

  • If possible, embed your images in your email. The email won't have to reach out to an external web server to download them and they won't appear as attachments to the email.

And lastly, test, test, test! Each email client does things way differently than a browser would do.

How can query string parameters be forwarded through a proxy_pass with nginx?

I use a slightly modified version of kolbyjack's second approach with ~ instead of ~*.

location ~ ^/service/ {
  proxy_pass http://apache/$uri$is_args$args;
}

How to completely DISABLE any MOUSE CLICK

You can add a simple css3 rule in the body or in specific div, use pointer-events: none; property.

IIS7 folder permissions for web application

Running IIS 7.5, I had luck adding permissions for the local computer user IUSR. The app pool user didn't work.

Javascript - How to extract filename from a file input control

 
// HTML
<input type="file" onchange="getFileName(this)">

// JS
function getFileName(input) {
    console.log(input.files[0].name) // With extension
    console.log(input.files[0].name.replace(/\.[^/.]+$/, '')) // Without extension
}

How to remove the extension

How do you get an iPhone's device name

In addition to the above answer, this is the actual code:

[[UIDevice currentDevice] name];

Mockito : doAnswer Vs thenReturn

doAnswer and thenReturn do the same thing if:

  1. You are using Mock, not Spy
  2. The method you're stubbing is returning a value, not a void method.

Let's mock this BookService

public interface BookService {
    String getAuthor();
    void queryBookTitle(BookServiceCallback callback);
}

You can stub getAuthor() using doAnswer and thenReturn.

BookService service = mock(BookService.class);
when(service.getAuthor()).thenReturn("Joshua");
// or..
doAnswer(new Answer() {
    @Override
    public Object answer(InvocationOnMock invocation) throws Throwable {
        return "Joshua";
    }
}).when(service).getAuthor();

Note that when using doAnswer, you can't pass a method on when.

// Will throw UnfinishedStubbingException
doAnswer(invocation -> "Joshua").when(service.getAuthor());

So, when would you use doAnswer instead of thenReturn? I can think of two use cases:

  1. When you want to "stub" void method.

Using doAnswer you can do some additionals actions upon method invocation. For example, trigger a callback on queryBookTitle.

BookServiceCallback callback = new BookServiceCallback() {
    @Override
    public void onSuccess(String bookTitle) {
        assertEquals("Effective Java", bookTitle);
    }
};
doAnswer(new Answer() {
    @Override
    public Object answer(InvocationOnMock invocation) throws Throwable {
        BookServiceCallback callback = (BookServiceCallback) invocation.getArguments()[0];
        callback.onSuccess("Effective Java");
        // return null because queryBookTitle is void
        return null;
    }
}).when(service).queryBookTitle(callback);
service.queryBookTitle(callback);
  1. When you are using Spy instead of Mock

When using when-thenReturn on Spy Mockito will call real method and then stub your answer. This can cause a problem if you don't want to call real method, like in this sample:

List list = new LinkedList();
List spy = spy(list);
// Will throw java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
when(spy.get(0)).thenReturn("java");
assertEquals("java", spy.get(0));

Using doAnswer we can stub it safely.

List list = new LinkedList();
List spy = spy(list);
doAnswer(invocation -> "java").when(spy).get(0);
assertEquals("java", spy.get(0));

Actually, if you don't want to do additional actions upon method invocation, you can just use doReturn.

List list = new LinkedList();
List spy = spy(list);
doReturn("java").when(spy).get(0);
assertEquals("java", spy.get(0));

How to rename a class and its corresponding file in Eclipse?

Click on the class and press the Alt + Shift + R keys, then you can change it to the required name and the corresponding file name will also be changed.

Animate visibility modes, GONE and VISIBLE

This is a quite old question, still comments show, that still people have problems, so here is my solution with following additional features:

  • adjust the animation (speed, type, ...)
  • does not need to extend any class
  • in my case, animateLayoutChanges has problems in the new CoordinatorLayout

Function - Example (I have this function in an utility class)

public static void animateViewVisibility(final View view, final int visibility)
{
    // cancel runnning animations and remove and listeners
    view.animate().cancel();
    view.animate().setListener(null);

    // animate making view visible
    if (visibility == View.VISIBLE)
    {
        view.animate().alpha(1f).start();
        view.setVisibility(View.VISIBLE);
    }
    // animate making view hidden (HIDDEN or INVISIBLE)
    else
    {
        view.animate().setListener(new AnimatorListenerAdapter()
        {
            @Override
            public void onAnimationEnd(Animator animation)
            {
                view.setVisibility(visibility);
            }
        }).alpha(0f).start();
    }
}

Adjust animation

After calling view.animate() you can adjust the animation to whatever you want (set duration, set interpolator and more...). You may as well hide a view by scaling it instead of adjusting it's alpha value, just replace the alpha(...) with scaleX(...) or scaleY(...) in the utility method if you want that

error: (-215) !empty() in function detectMultiScale

You may find such kind of errors when you did not define the complete path of your XML file. Try this one if you are using opencv3.1.0 in raspberrypi 3: "faceCascade = cv2.CascadeClassifier('/home/pi/opencv-3.1.0/data/haarcascades/haarcascade_frontalface_default.xml')"

java.lang.IllegalArgumentException: No converter found for return value of type

I was facing same issue for long time then comes to know have to convert object into JSON using Object Mapper and pass it as JSON Object 

@RequestMapping(value = "/getTags", method = RequestMethod.GET)
public @ResponseBody String getTags(@RequestParam String tagName) throws
        JsonGenerationException, JsonMappingException, IOException {
    List<Tag> result = new ArrayList<Tag>();
    for (Tag tag : data) {
        if (tag.getTagName().contains(tagName)) {
            result.add(tag);
        }
    }
    ObjectMapper objectMapper = new ObjectMapper();
    String json = objectMapper.writeValueAsString(result);
    return json;
}

Best way to store date/time in mongodb

The best way is to store native JavaScript Date objects, which map onto BSON native Date objects.

> db.test.insert({date: ISODate()})
> db.test.insert({date: new Date()})
> db.test.find()
{ "_id" : ObjectId("..."), "date" : ISODate("2014-02-10T10:50:42.389Z") }
{ "_id" : ObjectId("..."), "date" : ISODate("2014-02-10T10:50:57.240Z") }

The native type supports a whole range of useful methods out of the box, which you can use in your map-reduce jobs, for example.

If you need to, you can easily convert Date objects to and from Unix timestamps1), using the getTime() method and Date(milliseconds) constructor, respectively.

1) Strictly speaking, the Unix timestamp is measured in seconds. The JavaScript Date object measures in milliseconds since the Unix epoch.

drop down list value in asp.net

try this one

    <asp:DropDownList ID="ddList" runat="server">
    <asp:ListItem Value="">--Select Month--</asp:ListItem>
    <asp:ListItem Value="1">January</asp:ListItem>
    <asp:ListItem Value="2">Feburary</asp:ListItem>
    ...
    <asp:ListItem Value="12">December</asp:ListItem>
    </asp:DropDownList>

Value should be empty for the default selected listitem, then it works fine

Symfony 2 EntityManager injection in service

Since 2017 and Symfony 3.3 you can register Repository as service, with all its advantages it has.

Check my post How to use Repository with Doctrine as Service in Symfony for more general description.

To your specific case, original code with tuning would look like this:

1. Use in your services or Controller

<?php

namespace Test\CommonBundle\Services;

use Doctrine\ORM\EntityManagerInterface;

class UserService
{
    private $userRepository;

    // use custom repository over direct use of EntityManager
    // see step 2
    public function __constructor(UserRepository $userRepository)
    {
        $this->userRepository = $userRepository;
    }

    public function getUser($userId)
    {
        return $this->userRepository->find($userId);
    }
}

2. Create new custom repository

<?php

namespace Test\CommonBundle\Repository;

use Doctrine\ORM\EntityManagerInterface;

class UserRepository
{
    private $repository;

    public function __construct(EntityManagerInterface $entityManager)
    {
        $this->repository = $entityManager->getRepository(UserEntity::class);
    }

    public function find($userId)
    {
        return  $this->repository->find($userId);
    }
}

3. Register services

# app/config/services.yml
services:
    _defaults:
        autowire: true

    Test\CommonBundle\:
       resource: ../../Test/CommonBundle

AttributeError: 'dict' object has no attribute 'predictors'

 
#Try without dot notation
sample_dict = {'name': 'John', 'age': 29}
print(sample_dict['name']) # John
print(sample_dict['age']) # 29

IIS7 deployment - duplicate 'system.web.extensions/scripting/scriptResourceHandler' section

This error message seems to come up in various situations.

In my case, on top of my application's Web.Config file I had an extra Web.Config file in the root folder (C:\Inetpub\www.root). Probably left there after some testing, I had forgotten all about it, and couldn't figure out what the problem was.

Removing it solved the problem for me.

Is there any way I can define a variable in LaTeX?

If you want to use \newcommand, you can also include \usepackage{xspace} and define command by \newcommand{\newCommandName}{text to insert\xspace}. This can allow you to just use \newCommandName rather than \newCommandName{}.

For more detail, http://www.math.tamu.edu/~harold.boas/courses/math696/why-macros.html

Watching variables in SSIS during debug

I believe you can only add variables to the Watch window while the debugger is stopped on a breakpoint. If you set a breakpoint on a step, you should be able to enter variables into the Watch window when the breakpoint is hit. You can select the first empty row in the Watch window and enter the variable name (you may or may not get some Intellisense there, I can't remember how well that works.)

JQuery to load Javascript file dynamically

Yes, use getScript instead of document.write - it will even allow for a callback once the file loads.

You might want to check if TinyMCE is defined, though, before including it (for subsequent calls to 'Add Comment') so the code might look something like this:

$('#add_comment').click(function() {
    if(typeof TinyMCE == "undefined") {
        $.getScript('tinymce.js', function() {
            TinyMCE.init();
        });
    }
});

Assuming you only have to call init on it once, that is. If not, you can figure it out from here :)

how to create inline style with :before and :after

You can, using CSS variables (more precisely called CSS custom properties).

  • Set your variable in your style attribute:
    style="--my-color-var: orange;"
  • Use the variable in your stylesheet:
    background-color: var(--my-color-var);

Browser compatibility

Minimal example:

_x000D_
_x000D_ 
div {
  width: 100px;
  height: 100px;
  position: relative;
  border: 1px solid black;
}

div:after {
  background-color: var(--my-color-var);
  content: '';
  position: absolute;
  top: 0;
  bottom: 0;
  right: 0;
  left: 0;
}
_x000D_ 
<div style="--my-color-var: orange;"></div>
_x000D_
_x000D_
_x000D_

Your example:

_x000D_
_x000D_ 
.bubble {
  position: relative;
  width: 30px;
  height: 15px;
  padding: 0;
  background: #FFF;
  border: 1px solid #000;
  border-radius: 5px;
  text-align: center;
  background-color: var(--bubble-color);
}

.bubble:after {
  content: "";
  position: absolute;
  top: 4px;
  left: -4px;
  border-style: solid;
  border-width: 3px 4px 3px 0;
  border-color: transparent var(--bubble-color);
   display: block;
  width: 0;
  z-index: 1;
  
}

.bubble:before {
  content: "";
  position: absolute;
  top: 4px;
  left: -5px;
  border-style: solid;
  border-width: 3px 4px 3px 0;
  border-color: transparent #000;
  display: block;
  width: 0;
  z-index: 0;
}
_x000D_ 
<div class='bubble' style="--bubble-color: rgb(100,255,255);"> 100 </div>
_x000D_
_x000D_
_x000D_

Python - 'ascii' codec can't decode byte

Always encode from unicode to bytes.
In this direction, you get to choose the encoding. 

>>> u"??".encode("utf8")
'\xe4\xbd\xa0\xe5\xa5\xbd'
>>> print _
??

The other way is to decode from bytes to unicode.
In this direction, you have to know what the encoding is.

>>> bytes = '\xe4\xbd\xa0\xe5\xa5\xbd'
>>> print bytes
??
>>> bytes.decode('utf-8')
u'\u4f60\u597d'
>>> print _
??

This point can't be stressed enough. If you want to avoid playing unicode "whack-a-mole", it's important to understand what's happening at the data level. Here it is explained another way:

  • A unicode object is decoded already, you never want to call decode on it.
  • A bytestring object is encoded already, you never want to call encode on it.

Now, on seeing .encode on a byte string, Python 2 first tries to implicitly convert it to text (a unicode object). Similarly, on seeing .decode on a unicode string, Python 2 implicitly tries to convert it to bytes (a str object).

These implicit conversions are why you can get UnicodeDecodeError when you've called encode. It's because encoding usually accepts a parameter of type unicode; when receiving a str parameter, there's an implicit decoding into an object of type unicode before re-encoding it with another encoding. This conversion chooses a default 'ascii' decoder†, giving you the decoding error inside an encoder.

In fact, in Python 3 the methods str.decode and bytes.encode don't even exist. Their removal was a [controversial] attempt to avoid this common confusion.

† ...or whatever coding sys.getdefaultencoding() mentions; usually this is 'ascii'

Regular Expressions: Search in list

To do so without compiling the Regex first, use a lambda function - for example:

from re import match

values = ['123', '234', 'foobar']
filtered_values = list(filter(lambda v: match('^\d+$', v), values))

print(filtered_values)

Returns:

['123', '234']

filter() just takes a callable as it's first argument, and returns a list where that callable returned a 'truthy' value.

List<T> or IList<T>

List<T> is a specific implementation of IList<T>, which is a container that can be addressed the same way as a linear array T[] using an integer index. When you specify IList<T> as the type of the method's argument, you only specify that you need certain capabilities of the container.

For example, the interface specification does not enforce a specific data structure to be used. The implementation of List<T> happens to the same performance for accessing, deleting and adding elements as a linear array. However, you could imagine an implementation that is backed by a linked list instead, for which adding elements to the end is cheaper (constant-time) but random-access much more expensive. (Note that the .NET LinkedList<T> does not implement IList<T>.)

This example also tells you that there may be situations when you need to specify the implementation, not the interface, in the argument list: In this example, whenever you require a particular access performance characteristic. This is usually guaranteed for a specific implementation of a container (List<T> documentation: "It implements the IList<T> generic interface using an array whose size is dynamically increased as required.").

Additionally, you might want to consider exposing the least functionality you need. For example. if you don't need to change the content of the list, you should probably consider using IEnumerable<T>, which IList<T> extends.

How to detect when cancel is clicked on file input?

A lot of people keep suggesting the change event... even though OP specified that this doesn't work in the question:

CLICKING CANCEL DOES NOT SELECT A FILE AND THUS WILL NOT TRIGGER A CHANGE TO FILE INPUT!!!

all the code most people are suggesting will NOT run when cancel is clicked.

After a lot of experimentation based on suggestions from people who actually read OP's question, I've come up with this class to wrap the functionality of the file input and added two custom events:

  • choose: The user has chosen a file (still triggers if they select the same file again).
  • cancel: The user has clicked cancel or otherwise closed the file dialog with no selection.

I've also added redundancy (listen to multiple events to try and determine if cancel was pressed). Might not always respond right away but should at least guarantee that a cancel event is registered when the user re-engages the page.

Finally I noticed that events are not always guaranteed to happen in the same order (especially when the dialog closing triggers them all at nearly the same instant). This class waits for 100ms to make sure that the change event has fired before it checks for a success flag.

Uses ES6 class so probably won't work for anything before that FYI, though you could probably edit it if you wanna waste your time making it work on IE .

The Class:

class FileManager {
    // Keep important properties from being overwritten
    constructor() {
        Object.defineProperties(this, {
            // The file input element (hidden)
            _fileInput: {
                value: document.createElement('input'),
                writeable: false,
                enumerable: false,
                configurable: false
            },
            // Flag to denote if a file was chosen
            _chooseSuccess: {
                value: false,
                writable: true,
            },
            // Keeps events from mult-firing
            // Don't want to consume just incase!
            _eventFiredOnce: {
                value: false,
                writable: true,
            },
            // Called BEFORE dialog is shown
            _chooseStart_handler: {
                value: (event) => {
                    // Choose might happen, assume it won't
                    this._chooseSuccess = false;

                    // Allow a single fire
                    this._eventFiredOnce = false;

                    // Reset value so repeat files also trigger a change/choose
                    this._fileInput.value = '';



                    /* File chooser is semi-modal and will stall events while it's opened */
                    /* Beware, some code can still run while the dialog is opened! */

                    // Window will usually focus on dialog close
                    // If it works this is best becuase the event will trigger as soon as the dialog is closed
                    // Even the user has moved the dialog off of the browser window is should still refocus
                    window.addEventListener('focus', this._chooseEnd_handler);

                    // This will always fire when the mouse first enters the body
                    // A good redundancy but will not fire immeditely if the cance button is not...
                    // in window when clicked
                    document.body.addEventListener('mouseenter', this._chooseEnd_handler);

                    // Again almost a guarantee that this will fire but it will not do so...
                    // imediately if the dialog is out of window!
                    window.addEventListener('mousemove', this._chooseEnd_handler);
                },
                writeable: false,
                enumerable: false,
                configurable: false
            },
            _chooseEnd_handler: {
                // Focus event may beat change event
                // Wait 1/10th of a second to make sure change registers!
                value: (event) => {
                    // queue one event to fire
                    if (this._eventFiredOnce)
                        return;

                    // Mark event as fired once
                    this._eventFiredOnce = true;
                    // double call prevents 'this' context swap, IHT!
                    setTimeout((event) => {
                        this._timeout_handler(event);
                    }, 100);
                },
                writeable: false,
                enumerable: false,
                configurable: false
            },
            _choose_handler: {
                value: (event) => {
                    // A file was chosen by the user
                    // Set flag
                    this._chooseSuccess = true;
                    // End the choose
                    this._chooseEnd_handler(event);
                },
                writeable: false,
                enumerable: false,
                configurable: false
            },
            _timeout_handler: {
                value: (event) => {
                    if (!this._chooseSuccess) {
                        // Choose process done, no file selected
                        // Fire cancel event on input
                        this._fileInput.dispatchEvent(new Event('cancel'));
                    } else {
                        // Choose process done, file was selected
                        // Fire chosen event on input
                        this._fileInput.dispatchEvent(new Event('choose'));
                    }

                    // remove listeners or cancel will keep firing
                    window.removeEventListener('focus', this._chooseEnd_handler);
                    document.body.removeEventListener('mouseenter', this._chooseEnd_handler);
                    window.removeEventListener('mousemove', this._chooseEnd_handler);
                },
                writeable: false,
                enumerable: false,
                configurable: false
            },
            addEventListener: {
                value: (type, handle) => {
                    this._fileInput.addEventListener(type, handle);
                },
                writeable: false,
                enumerable: false,
                configurable: false
            },
            removeEventListener: {
                value: (type, handle) => {
                    this._fileInput.removeEventListener(type, handle);
                },
                writeable: false,
                enumerable: false,
                configurable: false
            },
            // Note: Shadow clicks must be called from a user input event stack!
            openFile: {
                value: () => {
                    // Trigger custom pre-click event
                    this._chooseStart_handler();

                    // Show file dialog
                    this._fileInput.click();
                    // ^^^ Code will still run after this part (non halting)
                    // Events will not trigger though until the dialog is closed
                }
            }
        });
        this._fileInput.type = 'file';
        this._fileInput.addEventListener('change', this._choose_handler);
    }

    // Get all files
    get files() {
        return this._input.files;
    }

    // Get input element (reccomended to keep hidden);
    get domElement(){
        return this._fileInput;
    }

    // Get specific file
    getFile(index) {
        return index === undefined ? this._fileInput.files[0] : this._fileInput.files[index];
    }

    // Set multi-select
    set multiSelect(value) {
        let val = value ? 'multiple' : '';
        this._fileInput.setAttribute('multiple', val);
    }

    // Get multi-select
    get multiSelect() {
        return this._fileInput.multiple === 'multiple' ? true : false;
    }
}

Usage Example:

// Instantiate
let fm = new FileManager();

// Bind to something that triggers a user input event (buttons are good)
let btn = document.getElementById('btn');

// Call openFile on intance to show the dialog to the user
btn.addEventListener('click', (event) => {
  fm.openFile();
});

// Fires if the user selects a file and clicks the 'okay' button
fm.addEventListener('choose', (event) => {
  console.log('file chosen: ' + fm.getFile(0).name);
});

// Fires if the user clicks 'cancel' or closes the file dialog
fm.addEventListener('cancel', (event) => {
  console.log('File choose has been canceled!');
});

Might be very late but I think this is a decent solution that covers most of the crippling edge cases. I'll be using this solution myself so I might come back with a git repo eventually after I play with it and refine it more.

Creating new table with SELECT INTO in SQL

The syntax for creating a new table is

CREATE TABLE new_table
AS
SELECT *
  FROM old_table

This will create a new table named new_table with whatever columns are in old_table and copy the data over. It will not replicate the constraints on the table, it won't replicate the storage attributes, and it won't replicate any triggers defined on the table.

SELECT INTO is used in PL/SQL when you want to fetch data from a table into a local variable in your PL/SQL block.

After installing with pip, "jupyter: command not found"

On Mac OS you need to export ~/.local/bin inside your $PATH variable.

# Edit the bash profile:
$ vim ~/.bash_profile

# Add this line inside ~/.bash_profile:
export PATH=$PATH:~/.local/bin

# Update the source:
$ source ~/.bash_profile

# Open Jupyter:
$ jupyter notebook

How to make Twitter Bootstrap menu dropdown on hover rather than click

I created a pure on hover dropdown menu based on the latest (v2.0.2) Bootstrap framework that has support for multiple submenus and thought I'd post it for future users:

_x000D_
_x000D_ 
body {_x000D_
  padding-top: 60px;_x000D_
  padding-bottom: 40px;_x000D_
}_x000D_
_x000D_
.sidebar-nav {_x000D_
  padding: 9px 0;_x000D_
}_x000D_
_x000D_
.dropdown-menu .sub-menu {_x000D_
  left: 100%;_x000D_
  position: absolute;_x000D_
  top: 0;_x000D_
  visibility: hidden;_x000D_
  margin-top: -1px;_x000D_
}_x000D_
_x000D_
.dropdown-menu li:hover .sub-menu {_x000D_
  visibility: visible;_x000D_
}_x000D_
_x000D_
.dropdown:hover .dropdown-menu {_x000D_
  display: block;_x000D_
}_x000D_
_x000D_
.nav-tabs .dropdown-menu,_x000D_
.nav-pills .dropdown-menu,_x000D_
.navbar .dropdown-menu {_x000D_
  margin-top: 0;_x000D_
}_x000D_
_x000D_
.navbar .sub-menu:before {_x000D_
  border-bottom: 7px solid transparent;_x000D_
  border-left: none;_x000D_
  border-right: 7px solid rgba(0, 0, 0, 0.2);_x000D_
  border-top: 7px solid transparent;_x000D_
  left: -7px;_x000D_
  top: 10px;_x000D_
}_x000D_
_x000D_
.navbar .sub-menu:after {_x000D_
  border-top: 6px solid transparent;_x000D_
  border-left: none;_x000D_
  border-right: 6px solid #fff;_x000D_
  border-bottom: 6px solid transparent;_x000D_
  left: 10px;_x000D_
  top: 11px;_x000D_
  left: -6px;_x000D_
}
_x000D_ 
<link href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/2.3.2/css/bootstrap.min.css" rel="stylesheet" />_x000D_
_x000D_
<div class="navbar navbar-fixed-top">_x000D_
  <div class="navbar-inner">_x000D_
    <div class="container-fluid">_x000D_
      <a data-target=".nav-collapse" data-toggle="collapse" class="btn btn-navbar">_x000D_
        <span class="icon-bar"></span>_x000D_
        <span class="icon-bar"></span>_x000D_
        <span class="icon-bar"></span>_x000D_
      </a>_x000D_
      <a href="#" class="brand">Project name</a>_x000D_
      <div class="nav-collapse">_x000D_
        <ul class="nav">_x000D_
          <li class="active"><a href="#">Home</a></li>_x000D_
          <li><a href="#">Link</a></li>_x000D_
          <li><a href="#">Link</a></li>_x000D_
          <li><a href="#">Link</a></li>_x000D_
          <li class="dropdown">_x000D_
            <a data-toggle="dropdown" class="dropdown-toggle" href="#">Dropdown <b class="caret"></b></a>_x000D_
            <ul class="dropdown-menu">_x000D_
              <li>_x000D_
                <a href="#">2-level Dropdown <i class="icon-arrow-right"></i></a>_x000D_
                <ul class="dropdown-menu sub-menu">_x000D_
                  <li><a href="#">Action</a></li>_x000D_
                  <li><a href="#">Another action</a></li>_x000D_
                  <li><a href="#">Something else here</a></li>_x000D_
                  <li class="divider"></li>_x000D_
                  <li class="nav-header">Nav header</li>_x000D_
                  <li><a href="#">Separated link</a></li>_x000D_
                  <li><a href="#">One more separated link</a></li>_x000D_
                </ul>_x000D_
              </li>_x000D_
              <li><a href="#">Another action</a></li>_x000D_
              <li><a href="#">Something else here</a></li>_x000D_
              <li class="divider"></li>_x000D_
              <li class="nav-header">Nav header</li>_x000D_
              <li><a href="#">Separated link</a></li>_x000D_
              <li><a href="#">One more separated link</a></li>_x000D_
            </ul>_x000D_
          </li>_x000D_
        </ul>_x000D_
        <form action="" class="navbar-search pull-left">_x000D_
          <input type="text" placeholder="Search" class="search-query span2">_x000D_
        </form>_x000D_
        <ul class="nav pull-right">_x000D_
          <li><a href="#">Link</a></li>_x000D_
          <li class="divider-vertical"></li>_x000D_
          <li class="dropdown">_x000D_
            <a class="#" href="#">Menu</a>_x000D_
          </li>_x000D_
        </ul>_x000D_
      </div>_x000D_
      <!-- /.nav-collapse -->_x000D_
    </div>_x000D_
  </div>_x000D_
</div>_x000D_
_x000D_
<hr>_x000D_
_x000D_
<ul class="nav nav-pills">_x000D_
  <li class="active"><a href="#">Regular link</a></li>_x000D_
  <li class="dropdown">_x000D_
    <a href="#" data-toggle="dropdown" class="dropdown-toggle">Dropdown <b class="caret"></b></a>_x000D_
    <ul class="dropdown-menu" id="menu1">_x000D_
      <li>_x000D_
        <a href="#">2-level Menu <i class="icon-arrow-right"></i></a>_x000D_
        <ul class="dropdown-menu sub-menu">_x000D_
          <li><a href="#">Action</a></li>_x000D_
          <li><a href="#">Another action</a></li>_x000D_
          <li><a href="#">Something else here</a></li>_x000D_
          <li class="divider"></li>_x000D_
          <li class="nav-header">Nav header</li>_x000D_
          <li><a href="#">Separated link</a></li>_x000D_
          <li><a href="#">One more separated link</a></li>_x000D_
        </ul>_x000D_
      </li>_x000D_
      <li><a href="#">Another action</a></li>_x000D_
      <li><a href="#">Something else here</a></li>_x000D_
      <li class="divider"></li>_x000D_
      <li><a href="#">Separated link</a></li>_x000D_
    </ul>_x000D_
  </li>_x000D_
  <li class="dropdown">_x000D_
    <a href="#">Menu</a>_x000D_
  </li>_x000D_
  <li class="dropdown">_x000D_
    <a href="#">Menu</a>_x000D_
  </li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

Demo

When should an Excel VBA variable be killed or set to Nothing?

VB6/VBA uses deterministic approach to destoying objects. Each object stores number of references to itself. When the number reaches zero, the object is destroyed.

Object variables are guaranteed to be cleaned (set to Nothing) when they go out of scope, this decrements the reference counters in their respective objects. No manual action required.

There are only two cases when you want an explicit cleanup:

  1. When you want an object to be destroyed before its variable goes out of scope (e.g., your procedure is going to take long time to execute, and the object holds a resource, so you want to destroy the object as soon as possible to release the resource).

  2. When you have a circular reference between two or more objects.

    If objectA stores a references to objectB, and objectB stores a reference to objectA, the two objects will never get destroyed unless you brake the chain by explicitly setting objectA.ReferenceToB = Nothing or objectB.ReferenceToA = Nothing.

The code snippet you show is wrong. No manual cleanup is required. It is even harmful to do a manual cleanup, as it gives you a false sense of more correct code.

If you have a variable at a class level, it will be cleaned/destroyed when the class instance is destructed. You can destroy it earlier if you want (see item 1.).

If you have a variable at a module level, it will be cleaned/destroyed when your program exits (or, in case of VBA, when the VBA project is reset). You can destroy it earlier if you want (see item 1.).

Access level of a variable (public vs. private) does not affect its life time.

How does #include <bits/stdc++.h> work in C++?

It is basically a header file that also includes every standard library and STL include file. The only purpose I can see for it would be for testing and education.

Se e.g. GCC 4.8.0 /bits/stdc++.h source.

Using it would include a lot of unnecessary stuff and increases compilation time.

Edit: As Neil says, it's an implementation for precompiled headers. If you set it up for precompilation correctly it could, in fact, speed up compilation time depending on your project. (https://gcc.gnu.org/onlinedocs/gcc/Precompiled-Headers.html)

I would, however, suggest that you take time to learn about each of the sl/stl headers and include them separately instead, and not use "super headers" except for precompilation purposes.

How do I "commit" changes in a git submodule?

You can treat a submodule exactly like an ordinary repository. To propagate your changes upstream just commit and push as you would normally within that directory.

How to set width and height dynamically using jQuery

 
$("#mainTable").css("width", "200px");
$("#mainTable").css("height", "2000px");

Using column alias in WHERE clause of MySQL query produces an error

Standard SQL disallows references to column aliases in a WHERE clause. This restriction is imposed because when the WHERE clause is evaluated, the column value may not yet have been determined. For example, the following query is illegal:

SELECT id, COUNT(*) AS cnt FROM tbl_name WHERE cnt > 0 GROUP BY id;

php var_dump() vs print_r()

var_dump($var) shows in-depth details, by providing additional details of

  • data type of the value (including the descendant elements)
  • number of elements in a variable
  • length of the value

How to make node.js require absolute? (instead of relative)

Imho the easiest way to achieve this is by creating a symbolic link on app startup at node_modules/app (or whatever you call it) which points to ../app. Then you can just call require("app/my/module"). Symbolic links are available on all major platforms.

However, you should still split your stuff in smaller, maintainable modules which are installed via npm. You can also install your private modules via git-url, so there is no reason to have one, monolithic app-directory.

How to find time complexity of an algorithm

Although there are some good answers for this question. I would like to give another answer here with several examples of loop.

  • O(n): Time Complexity of a loop is considered as O(n) if the loop variables is incremented / decremented by a constant amount. For example following functions have O(n) time complexity.

    // Here c is a positive integer constant   
for (int i = 1; i <= n; i += c) {  
    // some O(1) expressions
}

for (int i = n; i > 0; i -= c) {
    // some O(1) expressions
}

  • O(n^c): Time complexity of nested loops is equal to the number of times the innermost statement is executed. For example the following sample loops have O(n^2) time complexity

    for (int i = 1; i <=n; i += c) {
   for (int j = 1; j <=n; j += c) {
      // some O(1) expressions
   }
}

for (int i = n; i > 0; i += c) {
   for (int j = i+1; j <=n; j += c) {
      // some O(1) expressions
}

    For example Selection sort and Insertion Sort have O(n^2) time complexity.

  • O(Logn) Time Complexity of a loop is considered as O(Logn) if the loop variables is divided / multiplied by a constant amount.

    for (int i = 1; i <=n; i *= c) {
   // some O(1) expressions
}
for (int i = n; i > 0; i /= c) {
   // some O(1) expressions
}

    For example Binary Search has O(Logn) time complexity.

  • O(LogLogn) Time Complexity of a loop is considered as O(LogLogn) if the loop variables is reduced / increased exponentially by a constant amount.

    // Here c is a constant greater than 1   
for (int i = 2; i <=n; i = pow(i, c)) { 
   // some O(1) expressions
}
//Here fun is sqrt or cuberoot or any other constant root
for (int i = n; i > 0; i = fun(i)) { 
   // some O(1) expressions
}

One example of time complexity analysis

int fun(int n)
{    
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j < n; j += i)
        {
            // Some O(1) task
        }
    }    
}

Analysis:

For i = 1, the inner loop is executed n times. For i = 2, the inner loop is executed approximately n/2 times. For i = 3, the inner loop is executed approximately n/3 times. For i = 4, the inner loop is executed approximately n/4 times. ……………………………………………………. For i = n, the inner loop is executed approximately n/n times.

So the total time complexity of the above algorithm is (n + n/2 + n/3 + … + n/n), Which becomes n * (1/1 + 1/2 + 1/3 + … + 1/n)

The important thing about series (1/1 + 1/2 + 1/3 + … + 1/n) is equal to O(Logn). So the time complexity of the above code is O(nLogn).

Ref: 1 2 3

What does "Object reference not set to an instance of an object" mean?

Most of the time, when you try to assing value into object, and if the value is null, then this kind of exception occur. Please check this link.

for the sake of self learning, you can put some check condition. like

if (myObj== null)
Console.Write("myObj is NULL");

Writing to CSV with Python adds blank lines

 
import csv

hello = [['Me','You'],['293', '219'],['13','15']]
length = len(hello[0])

with open('test1.csv', 'wb') as testfile:
    csv_writer = csv.writer(testfile)
    for y in range(length):
        csv_writer.writerow([x[y] for x in hello])

will produce an output like this

Me You
293 219
13 15

Hope this helps

How to initialize a vector of vectors on a struct?

You use new to perform dynamic allocation. It returns a pointer that points to the dynamically allocated object.

You have no reason to use new, since A is an automatic variable. You can simply initialise A using its constructor:

vector<vector<int> > A(dimension, vector<int>(dimension));

open existing java project in eclipse

If this is a simple Java project, You essentially create a new project and give the location of the existing code. The project wizard will tell you that it will use existing sources.

Also, Eclipse 3.3.2 is ancient history, you guys should really upgrade. This is like using Visual Studio 5.

How to backup Sql Database Programmatically in C#

Works for me:

public class BackupService
{
    private readonly string _connectionString;
    private readonly string _backupFolderFullPath;
    private readonly string[] _systemDatabaseNames = { "master", "tempdb", "model", "msdb" };

    public BackupService(string connectionString, string backupFolderFullPath)
    {
        _connectionString = connectionString;
        _backupFolderFullPath = backupFolderFullPath;
    }

    public void BackupAllUserDatabases()
    {
        foreach (string databaseName in GetAllUserDatabases())
        {
            BackupDatabase(databaseName);
        }
    }

    public void BackupDatabase(string databaseName)
    {
        string filePath = BuildBackupPathWithFilename(databaseName);

        using (var connection = new SqlConnection(_connectionString))
        {
            var query = String.Format("BACKUP DATABASE [{0}] TO DISK='{1}'", databaseName, filePath);

            using (var command = new SqlCommand(query, connection))
            {
                connection.Open();
                command.ExecuteNonQuery();
            }
        }
    }

    private IEnumerable<string> GetAllUserDatabases()
    {
        var databases = new List<String>();

        DataTable databasesTable;

        using (var connection = new SqlConnection(_connectionString))
        {
            connection.Open();

            databasesTable = connection.GetSchema("Databases");

            connection.Close();
        }

        foreach (DataRow row in databasesTable.Rows)
        {
            string databaseName = row["database_name"].ToString();

            if (_systemDatabaseNames.Contains(databaseName))
                continue;

            databases.Add(databaseName);
        }

        return databases;
    }

    private string BuildBackupPathWithFilename(string databaseName)
    {
        string filename = string.Format("{0}-{1}.bak", databaseName, DateTime.Now.ToString("yyyy-MM-dd"));

        return Path.Combine(_backupFolderFullPath, filename);
    }
}

Is it possible to use if...else... statement in React render function?

May be I'm too late here. But I hope this would help someone. First separate those two elements. 

renderLogout(){
<div>
   <LogoutButton onClick={this.handleLogoutClick} />
<div>
}

renderLogin(){
<div>
   <LoginButton onClick={this.handleLoginClick} />
<div>
}

Then you can call these functions from render function using if else statement.

render(){
if(this.state.result){
  return this.renderResult();
}else{
  return this.renderQuiz();
}}

This works for me. :)

assign headers based on existing row in dataframe in R

Very similar to Vishnu's answer but uses the lapply to map all the data to characters then to assign them as the headers. This is really helpful if your data is imported as factors.

DF[] <- lapply(DF, as.character)
colnames(DF) <- DF[1, ]
DF <- DF[-1 ,]

note that that if you have a lot of numeric data or factors you want you'll need to convert them back. In this case it may make sense to store the character data frame, extract the row you want, and then apply it to the original data frame

tempDF <- DF
tempDF[] <- lapply(DF, as.character)
colnames(DF) <- tempDF[1, ]
DF <- DF[-1 ,]
tempDF <- NULL

Difference between filter and filter_by in SQLAlchemy

filter_by uses keyword arguments, whereas filter allows pythonic filtering arguments like filter(User.name=="john")

Hide HTML element by id

 
.nav ul li a#nav-ask{
    display:none;
}

Convert integer to class Date

You can use ymd from lubridate

lubridate::ymd(v)
#[1] "2008-11-01"

Or anytime::anydate

anytime::anydate(v)
#[1] "2008-11-01"

What is the hamburger menu icon called and the three vertical dots icon called?

We call it the "ant" menu. Guess it was a good time to change since everyone had just gotten used to the hamburger.

What does <T> (angle brackets) mean in Java?

Generic classes are a type of class that takes in a data type as a parameter when it's created. This type parameter is specified using angle brackets and the type can change each time a new instance of the class is instantiated. For instance, let's create an ArrayList for Employee objects and another for Company objects

ArrayList<Employee> employees = new ArrayList<Employee>();
ArrayList<Company> companies = new ArrayList<Company>();

You'll notice that we're using the same ArrayList class to create both lists and we pass in the Employee or Company type using angle brackets. Having one generic class be able to handle multiple types of data cuts down on having a lot of classes that perform similar tasks. Generics also help to cut down on bugs by giving everything a strong type which helps the compiler point out errors. By specifying a type for ArrayList, the compiler will throw an error if you try to add an Employee to the Company list or vice versa.

ViewBag, ViewData and TempData

TempData

Basically it's like a DataReader, once read, data will be lost.

Check this Video

Example

public class HomeController : Controller
{
    public ActionResult Index()
    {
        ViewBag.Message = "Welcome to ASP.NET MVC!";
        TempData["T"] = "T";
        return RedirectToAction("About");
    }

    public ActionResult About()
    {
        return RedirectToAction("Test1");
    }

    public ActionResult Test1()
    {
        String str = TempData["T"]; //Output - T
        return View();
    }
}

If you pay attention to the above code, RedirectToAction has no impact over the TempData until TempData is read. So, once TempData is read, values will be lost.

How can i keep the TempData after reading?

Check the output in Action Method Test 1 and Test 2

public class HomeController : Controller
{
    public ActionResult Index()
    {
        ViewBag.Message = "Welcome to ASP.NET MVC!";
        TempData["T"] = "T";
        return RedirectToAction("About");
    }

    public ActionResult About()
    {
        return RedirectToAction("Test1");
    }

    public ActionResult Test1()
    {
        string Str = Convert.ToString(TempData["T"]);
        TempData.Keep(); // Keep TempData
        return RedirectToAction("Test2");
    }

    public ActionResult Test2()
    {
        string Str = Convert.ToString(TempData["T"]); //OutPut - T
        return View();
    }
}

If you pay attention to the above code, data is not lost after RedirectToAction as well as after Reading the Data and the reason is, We are using TempData.Keep(). is that

In this way you can make it persist as long as you wish in other controllers also.

ViewBag/ViewData

The Data will persist to the corresponding View

dictionary update sequence element #0 has length 3; 2 is required

I was getting this error when I was updating the dictionary with the wrong syntax:

Try with these:

lineItem.values.update({attribute,value})

instead of

lineItem.values.update({attribute:value})