Programs & Examples On #Vector graphics

Vector graphics is the use of geometrical primitives such as points, lines, curves, and shapes or polygon(s), which are all based on mathematical equations, to represent images in computer graphics. Images are drawn at run-time from the information stored, and so vector images do not get distorted after zoom/resize etc.

Do I use <img>, <object>, or <embed> for SVG files?

Found one solution with pure CSS and without double image downloading. It is not beautiful as I want, but it works.

<!DOCTYPE html>
<html>
  <head>
    <title>HTML5 SVG demo</title>
    <style type="text/css">
     .nicolas_cage {
         background: url('nicolas_cage.jpg');
         width: 20px;
         height: 15px;
     }
     .fallback {
     }
    </style>
  </head>
<body>
<svg xmlns="http://www.w3.org/2000/svg" width="0" height="0">
    <style>
    <![CDATA[ 
        .fallback { background: none; background-image: none; display: none; }
    ]]>
    </style>
</svg>

<!-- inline svg -->
<svg xmlns="http://www.w3.org/2000/svg" width="40" height="40">
  <switch>
     <circle cx="20" cy="20" r="18" stroke="grey" stroke-width="2" fill="#99FF66" />
     <foreignObject>
         <div class="nicolas_cage fallback"></div>
     </foreignObject>
  </switch>
</svg>
<hr/>
<!-- external svg -->
    <object type="image/svg+xml" data="circle_orange.svg">
        <div class="nicolas_cage fallback"></div>
    </object>
</body>
</html>

The idea is to insert special SVG with fallback style.

More details and testing process you can find in my blog.

SVG rounded corner

For my case I need to radius begin and end of path:

enter image description here

With stroke-linecap: round; I change it to what I want:

enter image description here

Change fill color on vector asset in Android Studio

Go to you MainActivity.java and below this code
-> NavigationView navigationView = findViewById(R.id.nav_view);
Add single line of code -> navigationView.setItemIconTintList(null);
i.e. the last line of my code

I hope this might solve your problem.

public class MainActivity extends AppCompatActivity {

    private AppBarConfiguration mAppBarConfiguration;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        DrawerLayout drawer = findViewById(R.id.drawer_layout);
        NavigationView navigationView = findViewById(R.id.nav_view);
        navigationView.setItemIconTintList(null);

How to get http headers in flask?

If any one's trying to fetch all headers that were passed then just simply use:

dict(request.headers)

it gives you all the headers in a dict from which you can actually do whatever ops you want to. In my use case I had to forward all headers to another API since the python API was a proxy

Comparing Arrays of Objects in JavaScript

As serialization doesn't work generally (only when the order of properties matches: JSON.stringify({a:1,b:2}) !== JSON.stringify({b:2,a:1})) you have to check the count of properties and compare each property as well:

_x000D_
_x000D_
const objectsEqual = (o1, o2) =>_x000D_
    Object.keys(o1).length === Object.keys(o2).length _x000D_
        && Object.keys(o1).every(p => o1[p] === o2[p]);_x000D_
_x000D_
const obj1 = { name: 'John', age: 33};_x000D_
const obj2 = { age: 33, name: 'John' };_x000D_
const obj3 = { name: 'John', age: 45 };_x000D_
        _x000D_
console.log(objectsEqual(obj1, obj2)); // true_x000D_
console.log(objectsEqual(obj1, obj3)); // false
_x000D_
_x000D_
_x000D_

If you need a deep comparison, you can call the function recursively:

_x000D_
_x000D_
const obj1 = { name: 'John', age: 33, info: { married: true, hobbies: ['sport', 'art'] } };_x000D_
const obj2 = { age: 33, name: 'John', info: { hobbies: ['sport', 'art'], married: true } };_x000D_
const obj3 = { name: 'John', age: 33 };_x000D_
_x000D_
const objectsEqual = (o1, o2) => _x000D_
    typeof o1 === 'object' && Object.keys(o1).length > 0 _x000D_
        ? Object.keys(o1).length === Object.keys(o2).length _x000D_
            && Object.keys(o1).every(p => objectsEqual(o1[p], o2[p]))_x000D_
        : o1 === o2;_x000D_
        _x000D_
console.log(objectsEqual(obj1, obj2)); // true_x000D_
console.log(objectsEqual(obj1, obj3)); // false
_x000D_
_x000D_
_x000D_

Then it's easy to use this function to compare objects in arrays:

const arr1 = [obj1, obj1];
const arr2 = [obj1, obj2];
const arr3 = [obj1, obj3];

const arraysEqual = (a1, a2) => 
   a1.length === a2.length && a1.every((o, idx) => objectsEqual(o, a2[idx]));

console.log(arraysEqual(arr1, arr2)); // true
console.log(arraysEqual(arr1, arr3)); // false

What is the best free memory leak detector for a C/C++ program and its plug-in DLLs?

I have had good experiences with Rational Purify. I have also heard nice things about Valgrind

How to include file in a bash shell script

Yes, use source or the short form which is just .:

. other_script.sh

How does Python's super() work with multiple inheritance?

In python 3.5+ inheritance looks predictable and very nice for me. Please looks at this code:

class Base(object):
  def foo(self):
    print("    Base(): entering")
    print("    Base(): exiting")


class First(Base):
  def foo(self):
    print("   First(): entering Will call Second now")
    super().foo()
    print("   First(): exiting")


class Second(Base):
  def foo(self):
    print("  Second(): entering")
    super().foo()
    print("  Second(): exiting")


class Third(First, Second):
  def foo(self):
    print(" Third(): entering")
    super().foo()
    print(" Third(): exiting")


class Fourth(Third):
  def foo(self):
    print("Fourth(): entering")
    super().foo()
    print("Fourth(): exiting")

Fourth().foo()
print(Fourth.__mro__)

Outputs:

Fourth(): entering
 Third(): entering
   First(): entering Will call Second now
  Second(): entering
    Base(): entering
    Base(): exiting
  Second(): exiting
   First(): exiting
 Third(): exiting
Fourth(): exiting
(<class '__main__.Fourth'>, <class '__main__.Third'>, <class '__main__.First'>, <class '__main__.Second'>, <class '__main__.Base'>, <class 'object'>)

As you can see, it calls foo exactly ONE time for each inherited chain in the same order as it was inherited. You can get that order by calling .mro :

Fourth -> Third -> First -> Second -> Base -> object

What is the use of adding a null key or value to a HashMap in Java?

I'm not positive what you're asking, but if you're looking for an example of when one would want to use a null key, I use them often in maps to represent the default case (i.e. the value that should be used if a given key isn't present):

Map<A, B> foo;
A search;
B val = foo.containsKey(search) ? foo.get(search) : foo.get(null);

HashMap handles null keys specially (since it can't call .hashCode() on a null object), but null values aren't anything special, they're stored in the map like anything else

When is the finalize() method called in Java?

When is the finalize() method called in Java?

The finalize method will be called after the GC detects that the object is no longer reachable, and before it actually reclaims the memory used by the object.

  • If an object never becomes unreachable, finalize() will never be called on it.

  • If the GC doesn't run then finalize() may never be called. (Normally, the GC only runs when the JVM decides that there is likely to enough garbage to make it worthwhile.)

  • It may take more than one GC cycle before the GC determines that a specific object is unreachable. (Java GCs are typically "generational" collectors ...)

  • Once the GC detects an object is unreachable and finalizable, it is places on a finalization queue. Finalization typically occurs asynchronously with the normal GC.

(The JVM spec actually allows a JVM to never run finalizers ... provided that it doesn't reclaim the space used by the objects. A JVM that was implemented this way would be crippled / useless, but it this behavior is "allowed".)

The upshot is that it is unwise to rely on finalization to do things that have to be done in a definite time-frame. It is "best practice" not to use them at all. There should be a better (i.e. more reliable) way to do whatever it is you are trying to do in the finalize() method.

The only legitimate use for finalization is to clean up resources associated with objects that have been lost by application code. Even then, you should try to write the application code so that it doesn't lose the objects in the first place. (For example, use Java 7+ try-with-resources to ensure that close() is always called ...)


I created a test class which writes into a file when the finalize() method is called by overriding it. It is not executed. Can anybody tell me the reason why it is not executing?

It is hard to say, but there are a few possibilities:

  • The object is not garbage collected because it is still reachable.
  • The object is not garbage collected because the GC doesn't run before your test finishes.
  • The object is found by the GC and placed in the finalization queue by the GC, but finalization isn't completed before your test finishes.

How to install SimpleJson Package for Python

Really simple way is:

pip install simplejson

Convert string to decimal, keeping fractions

I think your problem is when displaying the decimal, not the contents of it.

If you try

string value = "1200.00";
decimal d = decimal.Parse(s);
string s = d.ToString();

s will contain the string "1200".

However if you change your code to this

string value = "1200.00";
decimal d = decimal.Parse(s);
string s = d.ToString("0.00");

s will contain the string "1200.00" as you want it to do.

EDIT

Seems I'm braindead early in the morning today. I added the Parse statements now. However even my first code will output "1200.00", even if I expected it to output "1200". Seems like I'm learning something each day, and in this case obviously something that is quite basic.

So disregard this a an proper answer. We will probably need more code to identify your problem in this case.

Resolving require paths with webpack

If you're using create-react-app, you can simply add a .env file containing

NODE_PATH=src/

Source: https://medium.com/@ktruong008/absolute-imports-with-create-react-app-4338fbca7e3d

A reference to the dll could not be added

Normally in Visual Studio 2015 you should create the dll project as a C++ -> CLR project from Visual Studio's templates, but you can technically enable it after the fact:

The critical property is called Common Language Runtime Support set in your project's configuration. It's found under Configuration Properties > General > Common Language Runtime Support.

When doing this, VS will probably not update the 'Target .NET Framework' option (like it should). You can manually add this by unloading your project, editing the your_project.xxproj file, and adding/updating the Target .NET framework Version XML tag.

For a sample, I suggest creating a new solution as a C++ CLR project and examining the XML there, perhaps even diffing it to make sure there's nothing very important that's out of the ordinary.

IIS Manager in Windows 10

Press the Windows Key and type Windows Features, select the first entry Turn Windows Features On or Off.

Make sure the box next to IIS is checked. You good to go.

How do you decrease navbar height in Bootstrap 3?

For Bootstrap 4
Some of the previous answers are not working for Bootstrap 4. To reduce the size of the navigation bar in this version, I suggest eliminating the padding like this.

.navbar { padding-top: 0.25rem; padding-bottom: 0.25rem; }

You could try with other styles too.
The styles I found that define the total height of the navigation bar are:

  • padding-top and padding-bottom are set to 0.5rem for .navbar.
  • padding-top and padding-bottom are set to 0.5rem for .navbar-text.
  • besides a line-height of 1.5rem inherited from the body.

Thus, in total the navigation bar is 3.5 times the root font size.

In my case, which I was using big font sizes; I redefined the ".navbar" class in my CSS file like this:

.navbar {
  padding-top:    0.25rem; /* 0px does not look good on small screens */
  padding-bottom: 0.25rem;
  font-size: smaller;      /* Just because I am using big size font */
  line-height: 1em;
}

Final comment, avoid using absolute values when playing with the previous styles. Use the units rem or em instead.

Can my enums have friendly names?

They follow the same naming rules as variable names. Therefore they should not contain spaces.

Also what you are suggesting would be very bad practice anyway.

How to get disk capacity and free space of remote computer

$disk = Get-WmiObject Win32_LogicalDisk -ComputerName remotecomputer -Filter "DeviceID='C:'" |
Select-Object Size,FreeSpace

$disk.Size
$disk.FreeSpace

To extract the values only and assign them to a variable:

$disk = Get-WmiObject Win32_LogicalDisk -ComputerName remotecomputer -Filter "DeviceID='C:'" |
Foreach-Object {$_.Size,$_.FreeSpace}

What are the different usecases of PNG vs. GIF vs. JPEG vs. SVG?

The main difference is GIF is patented and a bit more widely supported. PNG is an open specification and alpha transparency is not supported in IE6. Support was improved in IE7, but not completely fixed.

As far as file sizes go, GIF has a smaller default color pallet, so they tend to be smaller file sizes at first glance. PNG files have a larger default pallet, however you can shrink their color pallet so that, when you do, they result in a smaller file size than GIF. The issue again is that this feature isn't as supported in Internet Explorer.

Also, because PNGs can support alpha transparency, they're the only option if you want a variation of transparency other than binary transparency.

How do I get the HTML code of a web page in PHP?

If your PHP server allows url fopen wrappers then the simplest way is:

$html = file_get_contents('https://stackoverflow.com/questions/ask');

If you need more control then you should look at the cURL functions:

$c = curl_init('https://stackoverflow.com/questions/ask');
curl_setopt($c, CURLOPT_RETURNTRANSFER, true);
//curl_setopt(... other options you want...)

$html = curl_exec($c);

if (curl_error($c))
    die(curl_error($c));

// Get the status code
$status = curl_getinfo($c, CURLINFO_HTTP_CODE);

curl_close($c);

How to list only top level directories in Python?

For a list of full path names I prefer this version to the other solutions here:

def listdirs(dir):
    return [os.path.join(os.path.join(dir, x)) for x in os.listdir(dir) 
        if os.path.isdir(os.path.join(dir, x))]

How to have multiple colors in a Windows batch file?

If your console supports ANSI colour codes (e.g. ConEmu, Clink or ANSICON) you can do this:

SET    GRAY=%ESC%[0m
SET     RED=%ESC%[1;31m
SET   GREEN=%ESC%[1;32m
SET  ORANGE=%ESC%[0;33m
SET    BLUE=%ESC%[0;34m
SET MAGENTA=%ESC%[0;35m
SET    CYAN=%ESC%[1;36m
SET   WHITE=%ESC%[1;37m

where ESC variable contains ASCII character 27.

I found a way to populate the ESC variable here: http://www.dostips.com/forum/viewtopic.php?p=6827#p6827 and using tasklist it's possible to test what DLLs are loaded into a process.

The following script gets the process ID of the cmd.exe that the script is running in. Checks if it has a dll that will add ANSI support injected, and then sets colour variables to contain escape sequences or be empty depending on whether colour is supported or not.

@echo off

call :INIT_COLORS

echo %RED%RED %GREEN%GREEN %ORANGE%ORANGE %BLUE%BLUE %MAGENTA%MAGENTA %CYAN%CYAN %WHITE%WHITE %GRAY%GRAY

:: pause if double clicked on instead of run from command line.
SET interactive=0
ECHO %CMDCMDLINE% | FINDSTR /L %COMSPEC% >NUL 2>&1
IF %ERRORLEVEL% == 0 SET interactive=1
@rem ECHO %CMDCMDLINE% %COMSPEC% %interactive%
IF "%interactive%"=="1" PAUSE
EXIT /B 0
Goto :EOF

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
: SUBROUTINES                                                          :
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

::::::::::::::::::::::::::::::::
:INIT_COLORS
::::::::::::::::::::::::::::::::

call :supportsANSI
if ERRORLEVEL 1 (
  SET GREEN=
  SET RED=
  SET GRAY=
  SET WHITE=
  SET ORANGE=
  SET CYAN=
) ELSE (

  :: If you can, insert ASCII CHAR 27 after equals and remove BL.String.CreateDEL_ESC routine
  set "ESC="
  :: use this if can't type ESC CHAR, it's more verbose, but you can copy and paste it
  call :BL.String.CreateDEL_ESC

  SET    GRAY=%ESC%[0m
  SET     RED=%ESC%[1;31m
  SET   GREEN=%ESC%[1;32m
  SET  ORANGE=%ESC%[0;33m
  SET    BLUE=%ESC%[0;34m
  SET MAGENTA=%ESC%[0;35m
  SET    CYAN=%ESC%[1;36m
  SET   WHITE=%ESC%[1;37m
)

exit /b

::::::::::::::::::::::::::::::::
:BL.String.CreateDEL_ESC
::::::::::::::::::::::::::::::::
:: http://www.dostips.com/forum/viewtopic.php?t=1733
::
:: Creates two variables with one character DEL=Ascii-08 and ESC=Ascii-27
:: DEL and ESC can be used  with and without DelayedExpansion
setlocal
for /F "tokens=1,2 delims=#" %%a in ('"prompt #$H#$E# & echo on & for %%b in (1) do rem"') do (
  ENDLOCAL
  set "DEL=%%a"
  set "ESC=%%b"
  goto :EOF
)

::::::::::::::::::::::::::::::::
:supportsANSI
::::::::::::::::::::::::::::::::
:: returns ERRORLEVEL 0 - YES, 1 - NO
::
:: - Tests for ConEmu, ANSICON and Clink
:: - Returns 1 - NO support, when called via "CMD /D" (i.e. no autoruns / DLL injection)
::   on a system that would otherwise support ANSI.

if "%ConEmuANSI%" == "ON" exit /b 0

call :getPID PID

setlocal

for /f usebackq^ delims^=^"^ tokens^=^* %%a in (`tasklist /fi "PID eq %PID%" /m /fo CSV`) do set "MODULES=%%a"

set MODULES=%MODULES:"=%
set NON_ANSI_MODULES=%MODULES%

:: strip out ANSI dlls from module list:
:: ANSICON adds ANSI64.dll or ANSI32.dll
set "NON_ANSI_MODULES=%NON_ANSI_MODULES:ANSI=%"
:: ConEmu attaches ConEmuHk but ConEmu also sets ConEmuANSI Environment VAR
:: so we've already checked for that above and returned early.
@rem set "NON_ANSI_MODULES=%NON_ANSI_MODULES:ConEmuHk=%"
:: Clink supports ANSI https://github.com/mridgers/clink/issues/54
set "NON_ANSI_MODULES=%NON_ANSI_MODULES:clink_dll=%"

if "%MODULES%" == "%NON_ANSI_MODULES%" endlocal & exit /b 1
endlocal

exit /b 0

::::::::::::::::::::::::::::::::
:getPID  [RtnVar]
::::::::::::::::::::::::::::::::
:: REQUIREMENTS:
::
:: Determine the Process ID of the currently executing script,
:: but in a way that is multiple execution safe especially when the script can be executing multiple times
::   - at the exact same time in the same millisecond,
::   - by multiple users,
::   - in multiple window sessions (RDP),
::   - by privileged and non-privileged (e.g. Administrator) accounts,
::   - interactively or in the background.
::   - work when the cmd.exe window cannot appear
::     e.g. running from TaskScheduler as LOCAL SERVICE or using the "Run whether user is logged on or not" setting
::
:: https://social.msdn.microsoft.com/Forums/vstudio/en-US/270f0842-963d-4ed9-b27d-27957628004c/what-is-the-pid-of-the-current-cmdexe?forum=msbuild
::
:: http://serverfault.com/a/654029/306
::
:: Store the Process ID (PID) of the currently running script in environment variable RtnVar.
:: If called without any argument, then simply write the PID to stdout.
::
::
setlocal disableDelayedExpansion
:getLock
set "lock=%temp%\%~nx0.%time::=.%.lock"
set "uid=%lock:\=:b%"
set "uid=%uid:,=:c%"
set "uid=%uid:'=:q%"
set "uid=%uid:_=:u%"
setlocal enableDelayedExpansion
set "uid=!uid:%%=:p!"
endlocal & set "uid=%uid%"
2>nul ( 9>"%lock%" (
  for /f "skip=1" %%A in (
    'wmic process where "name='cmd.exe' and CommandLine like '%%<%uid%>%%'" get ParentProcessID'
  ) do for %%B in (%%A) do set "PID=%%B"
  (call )
))||goto :getLock
del "%lock%" 2>nul
endlocal & if "%~1" equ "" (echo(%PID%) else set "%~1=%PID%"
exit /b

Fastest way to ping a network range and return responsive hosts?

Try this for a unique list.

ping -c 5 -b 10.10.0.255 | grep 'bytes from' | awk '{ print $4 }' | sort | uniq

another method (fetches live hosts):

fping -ag 192.168.1.0/24

How to keep the local file or the remote file during merge using Git and the command line?

git checkout {branch-name} -- {file-name}

This will use the file from the branch of choice.

I like this because posh-git autocomplete works great with this. It also removes any ambiguity as to which branch is remote and which is local. And --theirs didn't work for me anyways.

How to install Cmake C compiler and CXX compiler

The approach I use is to start the "Visual Studio Command Prompt" which can be found in the Start menu. E.g. my visual studio 2010 Express install has a shortcute Visual Studio Command Prompt (2010) at Start Menu\Programs\Microsoft Visual Studio 2010\Visual Studio Tools.

This shortcut prepares an environment by calling a script vcvarsall.bat where the compiler, linker, etc. are setup from the right Visual Studio installation.

Alternatively, if you already have a prompt open, you can prepare the environment by calling a similar script:

:: For x86 (using the VS100COMNTOOLS env-var)
call "%VS100COMNTOOLS%"\..\..\VC\bin\vcvars32.bat

or

:: For amd64 (using the full path)
call C:\Program Files\Microsoft Visual Studio 10.0\VC\bin\amd64\vcvars64.bat

However:

Your output (with the '$' prompt) suggests that you are attempting to run CMake from a MSys shell. In that case it might be better to run CMake for MSys or MinGW, by explicitly specifying a makefile generator:

cmake -G"MSYS Makefiles"
cmake -G"MinGW Makefiles"

Run cmake --help to get a list of all possible generators.

Format a JavaScript string using placeholders and an object of substitutions?

You can use JQuery(jquery.validate.js) to make it work easily.

$.validator.format("My name is {0}, I'm {1} years old",["Bob","23"]);

Or if you want to use just that feature you can define that function and just use it like

function format(source, params) {
    $.each(params,function (i, n) {
        source = source.replace(new RegExp("\\{" + i + "\\}", "g"), n);
    })
    return source;
}
alert(format("{0} is a {1}", ["Michael", "Guy"]));

credit to jquery.validate.js team

how to remove key+value from hash in javascript

You say you don't necessarily know that 'key2' is in position [1]. Well, it's not. Position 1 would be occupied by myHash[1].

You're abusing JavaScript arrays, which (like functions) allow key/value hashes. Even though JavaScript allows it, it does not give you facilities to deal with it, as a language designed for associative arrays would. JavaScript's array methods work with the numbered properties only.

The first thing you should do is switch to objects rather than arrays. You don't have a good reason to use an array here rather than an object, so don't do it. If you want to use an array, just number the elements and give up on the idea of hashes. The intent of an array is to hold information which can be indexed into numerically.

You can, of course, put a hash (object) into an array if you like.

myhash[1]={"key1","brightOrangeMonkey"};

Twitter Bootstrap add active class to li

If you are using an MVC framework with routes and actions:

$(document).ready(function () {
    $('a[href="' + this.location.pathname + '"]').parent().addClass('active');
});

As illustrated in this answer by Christian Landgren: https://stackoverflow.com/a/13375529/101662

WebDriverException: unknown error: DevToolsActivePort file doesn't exist while trying to initiate Chrome Browser

In my case, I was trying to create a runnable jar on Windows OS with chrome browser and want to run the same on headless mode in unix box with CentOs on it. And I was pointing my binary to a driver that I have downloaded and packaged with my suite. For me, this issue continue to occur irrespective of adding the below:

ChromeOptions options = new ChromeOptions();
options.addArguments("--headless");
options.addArguments("--no-sandbox");
System.setProperty("webdriver.chrome.args", "--disable-logging");
System.setProperty("webdriver.chrome.silentOutput", "true");
options.setBinary("/pointing/downloaded/driver/path/in/automationsuite");
options.addArguments("--disable-dev-shm-usage"); // overcome limited resource problems
options.addArguments("disable-infobars"); // disabling infobars
options.addArguments("--disable-extensions"); // disabling extensions
options.addArguments("--disable-gpu"); // applicable to windows os only
options.addArguments("--disable-dev-shm-usage"); // overcome limited resource problems
options.addArguments("window-size=1024,768"); // Bypass OS security model
options.addArguments("--log-level=3"); // set log level
options.addArguments("--silent");//
options.setCapability("chrome.verbose", false); //disable logging
driver = new ChromeDriver(options);

Solution that I've tried and worked for me is, download the chrome and its tools on the host VM/Unix box, install and point the binary to this in the automation suite and bingo! It works :)

Download command:

wget https://dl.google.com/linux/direct/google-chrome-stable_current_x86_64.rpm

Install command:

sudo yum install -y ./google-chrome-stable_current_*.rpm

Update suite with below binary path of google-chrome:

options.setBinary("/opt/google/chrome/google-chrome");

And.. it works!

Missing MVC template in Visual Studio 2015

In my case that happened when uninstalling AspNet 5 RC1 Update 1 to update it for .Net Core 1.0 RC2. so I installed Visual Studio 2015 update 2, selected Microsoft Web Developer tools and everything went back to normal.

Is it possible that one domain name has multiple corresponding IP addresses?

Yes this is possible, however not convenient as Jens said. Using Next generation load balancers like Alteon, which Uses a proprietary protocol called DSSP(Distributed site state Protocol) which performs regular site checks to make sure that the service is available both Locally or Globally i.e different geographical areas. You need to however in your Master DNS to delegate the URL or Service to the device by configuring it as an Authoritative Name Server for that IP or Service. By doing this, the device answers DNS queries where it will resolve the IP that has a service by Round-Robin or is not congested according to how you have chosen from several metrics.

How do I load an url in iframe with Jquery

here is Iframe in view:

<iframe class="img-responsive" id="ifmReport" width="1090" height="1200" >

    </iframe>

Load it in script:

 $('#ifmReport').attr('src', '/ReportViewer/ReportViewer.aspx');

Hide div if screen is smaller than a certain width

Is your logic not round the wrong way in that example, you have it hiding when the screen is bigger than 1024. Reverse the cases, make the none in to a block and vice versa.

Store an array in HashMap

Yes, the Map interface will allow you to store Arrays as values. Here's a very simple example:

int[] val = {1, 2, 3};
Map<String, int[]> map = new HashMap<String, int[]>();
map.put("KEY1", val);

Also, depending on your use case you may want to look at the Multimap support offered by guava.

How to check if internet connection is present in Java?

You should connect to the place that your actual application needs. Otherwise you're testing whether you have a connection to somewhere irrelevant (Google in this case).

In particular, if you're trying to talk to a web service, and if you're in control of the web service, it would be a good idea to have some sort of cheap "get the status" web method. That way you have a much better idea of whether your "real" call is likely to work.

In other cases, just opening a connection to a port that should be open may be enough - or sending a ping. InetAddress.isReachable may well be an appropriate API for your needs here.

Performing a Stress Test on Web Application?

Blaze meter has a chrome extension for recording sessions and exporting them to JMeter (currently requires login). You also have the option of paying them money to run it on their cluster of JMeter servers (their pricing seems much better than LoadImpact which I've just stopped using):

I don't have any association with them, I just like the look of their service, although I haven't used the paid version yet.

How can I output leading zeros in Ruby?

Use String#next as the counter.

>> n = "000"
>> 3.times { puts "file_#{n.next!}" }
file_001
file_002
file_003

next is relatively 'clever', meaning you can even go for

>> n = "file_000"
>> 3.times { puts n.next! }
file_001
file_002
file_003

How do you do exponentiation in C?

use the pow function (it takes floats/doubles though).

man pow:

   #include <math.h>

   double pow(double x, double y);
   float powf(float x, float y);
   long double powl(long double x, long double y);

EDIT: For the special case of positive integer powers of 2, you can use bit shifting: (1 << x) will equal 2 to the power x. There are some potential gotchas with this, but generally, it would be correct.

Regular Expression to match only alphabetic characters

[a-zA-Z] should do that just fine.

You can reference the cheat sheet.

JavaScript closures vs. anonymous functions

Let's look at both ways:

(function(){
    var i2 = i;
    setTimeout(function(){
        console.log(i2);
    }, 1000)
})();

Declares and immediately executes an anonymous function that runs setTimeout() within its own context. The current value of i is preserved by making a copy into i2 first; it works because of the immediate execution.

setTimeout((function(i2){
    return function() {
        console.log(i2);
    }
})(i), 1000);

Declares an execution context for the inner function whereby the current value of i is preserved into i2; this approach also uses immediate execution to preserve the value.

Important

It should be mentioned that the run semantics are NOT the same between both approaches; your inner function gets passed to setTimeout() whereas his inner function calls setTimeout() itself.

Wrapping both codes inside another setTimeout() doesn't prove that only the second approach uses closures, there's just not the same thing to begin with.

Conclusion

Both methods use closures, so it comes down to personal taste; the second approach is easier to "move" around or generalize.

Is it possible to make Font Awesome icons larger than 'fa-5x'?

  1. Just add the font awesome class like this:

    class="fa fa-plus-circle fa-3x"
    

    (You can increase the size as per 5x, 7x, 9x..)

  2. You can also add custom CSS.

How to find the Git commit that introduced a string in any branch?

--reverse is also helpful since you want the first commit that made the change:

git log --all -p --reverse --source -S 'needle'

This way older commits will appear first.

How can I convert a DateTime to the number of seconds since 1970?

That approach will be good if the date-time in question is in UTC, or represents local time in an area that has never observed daylight saving time. The DateTime difference routines do not take into account Daylight Saving Time, and consequently will regard midnight June 1 as being a multiple of 24 hours after midnight January 1. I'm unaware of anything in Windows that reports historical daylight-saving rules for the current locale, so I don't think there's any good way to correctly handle any time prior to the most recent daylight-saving rule change.

Oracle client ORA-12541: TNS:no listener

I also faced the same problem but I resolved the issue by starting the TNS listener in control panel -> administrative tools -> services ->oracle TNS listener start.I am using windows Xp and Toad to connect to Oracle.

How to set up devices for VS Code for a Flutter emulator

First, You have to install the Android Studio and Xcode to create phone emulator.

In VSCode you can use the Android IOS Emulator plugin to set the path of emulator to run.

Getting path relative to the current working directory?

You can use Environment.CurrentDirectory to get the current directory, and FileSystemInfo.FullPath to get the full path to any location. So, fully qualify both the current directory and the file in question, and then check whether the full file name starts with the directory name - if it does, just take the appropriate substring based on the directory name's length.

Here's some sample code:

using System;
using System.IO;

class Program
{
    public static void Main(string[] args)
    {
        string currentDir = Environment.CurrentDirectory;
        DirectoryInfo directory = new DirectoryInfo(currentDir);
        FileInfo file = new FileInfo(args[0]);

        string fullDirectory = directory.FullName;
        string fullFile = file.FullName;

        if (!fullFile.StartsWith(fullDirectory))
        {
            Console.WriteLine("Unable to make relative path");
        }
        else
        {
            // The +1 is to avoid the directory separator
            Console.WriteLine("Relative path: {0}",
                              fullFile.Substring(fullDirectory.Length+1));
        }
    }
}

I'm not saying it's the most robust thing in the world (symlinks could probably confuse it) but it's probably okay if this is just a tool you'll be using occasionally.

I need a Nodejs scheduler that allows for tasks at different intervals

I think the best ranking is

1.node-schedule

2.later

3.crontab

and the sample of node-schedule is below:

var schedule = require("node-schedule");
var rule = new schedule.RecurrenceRule();
//rule.minute = 40;
rule.second = 10;
var jj = schedule.scheduleJob(rule, function(){
    console.log("execute jj");
});

Maybe you can find the answer from node modules.

javascript getting my textbox to display a variable

_x000D_
_x000D_
function myfunction() {_x000D_
  var first = document.getElementById("textbox1").value;_x000D_
  var second = document.getElementById("textbox2").value;_x000D_
  var answer = parseFloat(first) + parseFloat(second);_x000D_
_x000D_
  var textbox3 = document.getElementById('textbox3');_x000D_
  textbox3.value = answer;_x000D_
}
_x000D_
<input type="text" name="textbox1" id="textbox1" /> + <input type="text" name="textbox2" id="textbox2" />_x000D_
<input type="submit" name="button" id="button1" onclick="myfunction()" value="=" />_x000D_
<br/> Your answer is:--_x000D_
<input type="text" name="textbox3" id="textbox3" readonly="true" />
_x000D_
_x000D_
_x000D_

Two Page Login with Spring Security 3.2.x

There should be three pages here:

  1. Initial login page with a form that asks for your username, but not your password.
  2. You didn't mention this one, but I'd check whether the client computer is recognized, and if not, then challenge the user with either a CAPTCHA or else a security question. Otherwise the phishing site can simply use the tendered username to query the real site for the security image, which defeats the purpose of having a security image. (A security question is probably better here since with a CAPTCHA the attacker could have humans sitting there answering the CAPTCHAs to get at the security images. Depends how paranoid you want to be.)
  3. A page after that that displays the security image and asks for the password.

I don't see this short, linear flow being sufficiently complex to warrant using Spring Web Flow.

I would just use straight Spring Web MVC for steps 1 and 2. I wouldn't use Spring Security for the initial login form, because Spring Security's login form expects a password and a login processing URL. Similarly, Spring Security doesn't provide special support for CAPTCHAs or security questions, so you can just use Spring Web MVC once again.

You can handle step 3 using Spring Security, since now you have a username and a password. The form login page should display the security image, and it should include the user-provided username as a hidden form field to make Spring Security happy when the user submits the login form. The only way to get to step 3 is to have a successful POST submission on step 1 (and 2 if applicable).

Checking if a collection is null or empty in Groovy

!members.find()

I think now the best way to solve this issue is code above. It works since Groovy 1.8.1 http://docs.groovy-lang.org/docs/next/html/groovy-jdk/java/util/Collection.html#find(). Examples:

def lst1 = []
assert !lst1.find()

def lst2 = [null]
assert !lst2.find()

def lst3 = [null,2,null]
assert lst3.find()

def lst4 = [null,null,null]
assert !lst4.find()

def lst5 = [null, 0, 0.0, false, '', [], 42, 43]
assert lst5.find() == 42

def lst6 = null; 
assert !lst6.find()

Play infinitely looping video on-load in HTML5

As of April 2018, Chrome (along with several other major browsers) now require the muted attribute too.

Therefore, you should use

<video width="320" height="240" autoplay loop muted>
  <source src="movie.mp4" type="video/mp4" />
</video>

How do I run git log to see changes only for a specific branch?

The problem I was having, which I think is similar to this, is that master was too far ahead of my branch point for the history to be useful. (Navigating to the branch point would take too long.)

After some trial and error, this gave me roughly what I wanted:

git log --graph --decorate --oneline --all ^master^!

How to dynamically load a Python class

def import_class(cl):
    d = cl.rfind(".")
    classname = cl[d+1:len(cl)]
    m = __import__(cl[0:d], globals(), locals(), [classname])
    return getattr(m, classname)

What's the best way to store Phone number in Django models

You might actually look into the internationally standardized format E.164, recommended by Twilio for example (who have a service and an API for sending SMS or phone-calls via REST requests).

This is likely to be the most universal way to store phone numbers, in particular if you have international numbers work with.

1. Phone by PhoneNumberField

You can use phonenumber_field library. It is port of Google's libphonenumber library, which powers Android's phone number handling https://github.com/stefanfoulis/django-phonenumber-field

In model:

from phonenumber_field.modelfields import PhoneNumberField

class Client(models.Model, Importable):
    phone = PhoneNumberField(null=False, blank=False, unique=True)

In form:

from phonenumber_field.formfields import PhoneNumberField
class ClientForm(forms.Form):
    phone = PhoneNumberField()

Get phone as string from object field:

    client.phone.as_e164 

Normolize phone string (for tests and other staff):

    from phonenumber_field.phonenumber import PhoneNumber
    phone = PhoneNumber.from_string(phone_number=raw_phone, region='RU').as_e164

2. Phone by regexp

One note for your model: E.164 numbers have a max character length of 15.

To validate, you can employ some combination of formatting and then attempting to contact the number immediately to verify.

I believe I used something like the following on my django project:

class ReceiverForm(forms.ModelForm):
    phone_number = forms.RegexField(regex=r'^\+?1?\d{9,15}$', 
                                error_message = ("Phone number must be entered in the format: '+999999999'. Up to 15 digits allowed."))

EDIT

It appears that this post has been useful to some folks, and it seems worth it to integrate the comment below into a more full-fledged answer. As per jpotter6, you can do something like the following on your models as well:

models.py:

from django.core.validators import RegexValidator

class PhoneModel(models.Model):
    ...
    phone_regex = RegexValidator(regex=r'^\+?1?\d{9,15}$', message="Phone number must be entered in the format: '+999999999'. Up to 15 digits allowed.")
    phone_number = models.CharField(validators=[phone_regex], max_length=17, blank=True) # validators should be a list

How to get 0-padded binary representation of an integer in java?

Starting with Java 11, you can use the repeat(...) method:

"0".repeat(Integer.numberOfLeadingZeros(i) - 16) + Integer.toBinaryString(i)

Or, if you need 32-bit representation of any integer:

"0".repeat(Integer.numberOfLeadingZeros(i != 0 ? i : 1)) + Integer.toBinaryString(i)

Console app arguments, how arguments are passed to Main method

The main method of the runtime engine looks something like int main(int argc, char *argv[]), where argc is a count of the number of arguments and argv is an array of pointers to each. The runtime engine converts this into a form that is more natural to c#.

Prior to that main method being called, everything is in assembly language. It has access to the command line arguments (because the operating system makes that available to every process that starts), but that assembly language needs to convert a single string of the full command line into multiple substrings (using whitespace to separate them) before it's ready to pass them into main().

How do I add a Fragment to an Activity with a programmatically created content view

public abstract class SingleFragmentActivity extends Activity {

    public static final String FRAGMENT_TAG = "single";
    private Fragment fragment;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
        if (savedInstanceState == null) {
            fragment = onCreateFragment();
           getFragmentManager().beginTransaction()
                   .add(android.R.id.content, fragment, FRAGMENT_TAG)
                   .commit();
       } else {
           fragment = getFragmentManager().findFragmentByTag(FRAGMENT_TAG);
       }
   }

   public abstract Fragment onCreateFragment();

   public Fragment getFragment() {
       return fragment;
   }

}

use

public class ViewCatalogItemActivity extends SingleFragmentActivity {
    @Override
    public Fragment onCreateFragment() {
        return new FragmentWorkShops();
    }

}

Using `window.location.hash.includes` throws “Object doesn't support property or method 'includes'” in IE11

As in Internet Explorer, the javascript method "includes" doesn't support which is leading to the error as below

dijit.form.FilteringSelect TypeError: Object doesn't support property or method 'includes'

So I have changed the JavaScript string method from "includes" to "indexOf" as below

//str1 doesn't match str2 w.r.t index, so it will try to add object
var str1="acd", str2="b";
if(str1.indexOf(str2) == -1) 
{
  alert("add object");
}
else 
{
 alert("object not added");
}

How to check what user php is running as?

You can use these commands :

<? system('whoami');?>

or

<? passthru('whoami');?>

or

<? print exec('whoami');?>

or

<? print shell_exec('whoami');?>

Be aware, the get_current_user() returns the name of the owner of the current PHP script !

Can the jQuery UI Datepicker be made to disable Saturdays and Sundays (and holidays)?

There is the beforeShowDay option, which takes a function to be called for each date, returning true if the date is allowed or false if it is not. From the docs:


beforeShowDay

The function takes a date as a parameter and must return an array with [0] equal to true/false indicating whether or not this date is selectable and 1 equal to a CSS class name(s) or '' for the default presentation. It is called for each day in the datepicker before is it displayed.

Display some national holidays in the datepicker.

$(".selector").datepicker({ beforeShowDay: nationalDays})   

natDays = [
  [1, 26, 'au'], [2, 6, 'nz'], [3, 17, 'ie'],
  [4, 27, 'za'], [5, 25, 'ar'], [6, 6, 'se'],
  [7, 4, 'us'], [8, 17, 'id'], [9, 7, 'br'],
  [10, 1, 'cn'], [11, 22, 'lb'], [12, 12, 'ke']
];

function nationalDays(date) {
    for (i = 0; i < natDays.length; i++) {
      if (date.getMonth() == natDays[i][0] - 1
          && date.getDate() == natDays[i][1]) {
        return [false, natDays[i][2] + '_day'];
      }
    }
  return [true, ''];
}

One built in function exists, called noWeekends, that prevents the selection of weekend days.

$(".selector").datepicker({ beforeShowDay: $.datepicker.noWeekends })

To combine the two, you could do something like (assuming the nationalDays function from above):

$(".selector").datepicker({ beforeShowDay: noWeekendsOrHolidays})   

function noWeekendsOrHolidays(date) {
    var noWeekend = $.datepicker.noWeekends(date);
    if (noWeekend[0]) {
        return nationalDays(date);
    } else {
        return noWeekend;
    }
}

Update: Note that as of jQuery UI 1.8.19, the beforeShowDay option also accepts an optional third paremeter, a popup tooltip

Installing Bootstrap 3 on Rails App

I actually had an easy workaround on this one in which I nearly scratch my head on how to make it work. hahah!

Well, first I downloaded Bootstrap (the compiled css and js version).

Then I pasted all the bootstrap css files to the app/assets/stylesheets/.

And then I pasted all the bootstrap js files to the app/assets/javascripts/.

I reloaded the page and wallah! I just added bootstrap in my RoR!

Python loop to run for certain amount of seconds

try this:

import time
import os

n = 0
for x in range(10): #enter your value here
    print(n)
    time.sleep(1) #to wait a second
    os.system('cls') #to clear previous number
                     #use ('clear') if you are using linux or mac!
    n = n + 1

MySQL Trigger after update only if row has changed

In here if there any row affect with new insertion Then it will update on different table in the database.

DELIMITER $$

CREATE TRIGGER "give trigger name" AFTER INSERT ON "table name" 
FOR EACH ROW
BEGIN
    INSERT INTO "give table name you want to add the new insertion on previously given table" (id,name,age) VALUES (10,"sumith",24);
END;
$$
DELIMITER ;

Quadratic and cubic regression in Excel

You need to use an undocumented trick with Excel's LINEST function:

=LINEST(known_y's, [known_x's], [const], [stats])

Background

A regular linear regression is calculated (with your data) as:

=LINEST(B2:B21,A2:A21)

which returns a single value, the linear slope (m) according to the formula:

enter image description here

which for your data:

enter image description here

is:

enter image description here

Undocumented trick Number 1

You can also use Excel to calculate a regression with a formula that uses an exponent for x different from 1, e.g. x1.2:

enter image description here

using the formula:

=LINEST(B2:B21, A2:A21^1.2)

which for you data:

enter image description here

is:

enter image description here

You're not limited to one exponent

Excel's LINEST function can also calculate multiple regressions, with different exponents on x at the same time, e.g.:

=LINEST(B2:B21,A2:A21^{1,2})

Note: if locale is set to European (decimal symbol ","), then comma should be replaced by semicolon and backslash, i.e. =LINEST(B2:B21;A2:A21^{1\2})

Now Excel will calculate regressions using both x1 and x2 at the same time:

enter image description here

How to actually do it

The impossibly tricky part there's no obvious way to see the other regression values. In order to do that you need to:

  • select the cell that contains your formula:

    enter image description here

  • extend the selection the left 2 spaces (you need the select to be at least 3 cells wide):

    enter image description here

  • press F2

  • press Ctrl+Shift+Enter

    enter image description here

You will now see your 3 regression constants:

  y = -0.01777539x^2 + 6.864151123x + -591.3531443

Bonus Chatter

I had a function that I wanted to perform a regression using some exponent:

y = m×xk + b

But I didn't know the exponent. So I changed the LINEST function to use a cell reference instead:

=LINEST(B2:B21,A2:A21^F3, true, true)

With Excel then outputting full stats (the 4th paramter to LINEST):

enter image description here

I tell the Solver to maximize R2:

enter image description here

And it can figure out the best exponent. Which for you data:

enter image description here

is:

enter image description here

How to escape the % (percent) sign in C's printf?

The backslash in C is used to escape characters in strings. Strings would not recognize % as a special character, and therefore no escape would be necessary. printf is another matter: use %% to print one %.

Backup/Restore a dockerized PostgreSQL database

dksnap (https://github.com/kelda/dksnap) automates the process of running pg_dumpall and loading the dump via /docker-entrypoint-initdb.d.

It shows you a list of running containers, and you pick which one you want to backup. The resulting artifact is a regular Docker image, so you can then docker run it, or share it by pushing it to a Docker registry.

(disclaimer: I'm a maintainer on the project)

Importing Maven project into Eclipse

I am not experienced with Eclipse or Maven so the other answers seemed a bit over complicated.

The following simpler set of steps worked for me:

Prerequisite: Make sure you have Maven plugin installed in your Eclipse IDE: How to add Maven plugin to Eclipse

  1. Open Eclipse
  2. Click File > Import
  3. Type Maven in the search box under Select an import source:
  4. Select Existing Maven Projects
  5. Click Next
  6. Click Browse and select the folder that is the root of the Maven project (probably contains the pom.xml file)
  7. Click Next
  8. Click Finish

Font from origin has been blocked from loading by Cross-Origin Resource Sharing policy

For those using Microsoft products with a web.config file:

Merge this with your web.config.

To allow on any domain replace value="domain" with value="*"

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <system.webserver>
    <httpprotocol>
      <customheaders>
        <add name="Access-Control-Allow-Origin" value="domain" />
      </customheaders>
    </httpprotocol>
  </system.webserver>
</configuration>

If you don't have permission to edit web.config, then add this line in your server-side code.

Response.AppendHeader("Access-Control-Allow-Origin", "domain");

compare differences between two tables in mysql

 select t1.user_id,t2.user_id 
 from t1 left join t2 ON t1.user_id = t2.user_id 
 and t1.username=t2.username 
 and t1.first_name=t2.first_name 
 and t1.last_name=t2.last_name

try this. This will compare your table and find all matching pairs, if any mismatch return NULL on left.

Difference and uses of onCreate(), onCreateView() and onActivityCreated() in fragments

onActivityCreated() - Deprecated

onActivityCreated() is now deprecated as Fragments Version 1.3.0-alpha02

The onActivityCreated() method is now deprecated. Code touching the fragment's view should be done in onViewCreated() (which is called immediately before onActivityCreated()) and other initialization code should be in onCreate(). To receive a callback specifically when the activity's onCreate() is complete, a LifeCycleObserver should be registered on the activity's Lifecycle in onAttach(), and removed once the onCreate() callback is received.

Detailed information can be found here

What is the difference between LATERAL and a subquery in PostgreSQL?

The difference between a non-lateral and a lateral join lies in whether you can look to the left hand table's row. For example:

select  *
from    table1 t1
cross join lateral
        (
        select  *
        from    t2
        where   t1.col1 = t2.col1 -- Only allowed because of lateral
        ) sub

This "outward looking" means that the subquery has to be evaluated more than once. After all, t1.col1 can assume many values.

By contrast, the subquery after a non-lateral join can be evaluated once:

select  *
from    table1 t1
cross join
        (
        select  *
        from    t2
        where   t2.col1 = 42 -- No reference to outer query
        ) sub

As is required without lateral, the inner query does not depend in any way on the outer query. A lateral query is an example of a correlated query, because of its relation with rows outside the query itself.

How can I prevent a window from being resized with tkinter?

Traceback (most recent call last):
  File "tkwindowwithlabel5.py", line 23, in <module>
    main()
  File "tkwindowwithlabel5.py", line 16, in main
    window.resizeable(width = True, height =True)
  File "/usr/lib/python3.4/tkinter/__init__.py", line 1935, in                
  __getattr__
    return getattr(self.tk, attr)
AttributeError: 'tkapp' object has no attribute 'resizeable'

is what you will get with the first answer. tk does support min and max size

window.minsize(width = X, height = x)
window.maxsize(width = X, height = x)

i figured it out but just trying the first one. using python3 with tk.

Counting null and non-null values in a single query

As i understood your query, You just run this script and get Total Null,Total NotNull rows,

select count(*) - count(a) as 'Null', count(a) as 'Not Null' from us;

Python convert set to string and vice versa

The question is little unclear because the title of the question is asking about string and set conversion but then the question at the end asks how do I serialize ? !

let me refresh the concept of Serialization is the process of encoding an object, including the objects it refers to, as a stream of byte data.

If interested to serialize you can use:

json.dumps  -> serialize
json.loads  -> deserialize

If your question is more about how to convert set to string and string to set then use below code (it's tested in Python 3)

String to Set

set('abca')

Set to String

''.join(some_var_set)

example:

def test():
    some_var_set=set('abca')
    print("here is the set:",some_var_set,type(some_var_set))
    some_var_string=''.join(some_var_set)    
    print("here is the string:",some_var_string,type(some_var_string))

test()

Nginx upstream prematurely closed connection while reading response header from upstream, for large requests

I ran into this issue as well and found this post. Ultimately none of these answers solved my problem, instead I had to put in a rewrite rule to strip out the location /rt as the backend my developers made was not expecting any additional paths:

+-(william@wkstn18)--(Thu, 05 Nov 20)-+
+-(~)--(16:13)->wscat -c ws://WebsocketServerHostname/rt
error: Unexpected server response: 502

Testing with wscat repeatedly gave a 502 response. Nginx error logs provided the same upstream error as above, but notice the upstream string shows the GET Request is attempting to access localhost:12775/rt and not localhost:12775:

 2020/11/05 22:13:32 [error] 10175#10175: *7 upstream prematurely closed
 connection while reading response header from upstream, client: WANIP,
 server: WebsocketServerHostname, request: "GET /rt/socket.io/?transport=websocket
 HTTP/1.1", upstream: "http://127.0.0.1:12775/rt/socket.io/?transport=websocket",
 host: "WebsocketServerHostname"

Since the devs had not coded their websocket (listening on 12775) to expect /rt/socket.io but instead just /socket.io/ (NOTE: /socket.io/ appears to just be a way to specify websocket transport discussed here). Because of this, rather than ask them to rewrite their socket code I just put in a rewrite rule to translate WebsocketServerHostname/rt to WebsocketServerHostname:12775 as below:

upstream websocket-rt {
        ip_hash;

        server 127.0.0.1:12775;
}

server {
        listen 80;
        server_name     WebsocketServerHostname;

        location /rt {
                proxy_http_version 1.1;

                #rewrite /rt/ out of all requests and proxy_pass to 12775
                rewrite /rt/(.*) /$1  break;

                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                proxy_set_header Host $host;

                proxy_pass http://websocket-rt;
                proxy_set_header Upgrade $http_upgrade;
                proxy_set_header Connection $connection_upgrade;
        }

}

Html: Difference between cell spacing and cell padding

CellSpacing as the name suggests it is the Space between the Adjacent cells and CellPadding on the other hand means the padding around the cell content.

Binding Combobox Using Dictionary as the Datasource

I used Sorin Comanescu's solution, but hit a problem when trying to get the selected value. My combobox was a toolstrip combobox. I used the "combobox" property, which exposes a normal combobox.

I had a

 Dictionary<Control, string> controls = new Dictionary<Control, string>();

Binding code (Sorin Comanescu's solution - worked like a charm):

 controls.Add(pictureBox1, "Image");
 controls.Add(dgvText, "Text");
 cbFocusedControl.ComboBox.DataSource = new BindingSource(controls, null);
 cbFocusedControl.ComboBox.ValueMember = "Key";
 cbFocusedControl.ComboBox.DisplayMember = "Value";

The problem was that when I tried to get the selected value, I didn't realize how to retrieve it. After several attempts I got this:

 var control = ((KeyValuePair<Control, string>) cbFocusedControl.ComboBox.SelectedItem).Key

Hope it helps someone else!

Cassandra port usage - how are the ports used?

@Schildmeijer is largely right, however port 7001 is still used when using TLS Encrypted Internode communication

So my complete list would be for current versions of Cassandra:

  • 7199 - JMX (was 8080 pre Cassandra 0.8.xx)
  • 7000 - Internode communication (not used if TLS enabled)
  • 7001 - TLS Internode communication (used if TLS enabled)
  • 9160 - Thrift client API
  • 9042 - CQL native transport port

Sort a list of numerical strings in ascending order

The recommended approach in this case is to sort the data in the database, adding an ORDER BY at the end of the query that fetches the results, something like this:

SELECT temperature FROM temperatures ORDER BY temperature ASC;  -- ascending order
SELECT temperature FROM temperatures ORDER BY temperature DESC; -- descending order

If for some reason that is not an option, you can change the sorting order like this in Python:

templist = [25, 50, 100, 150, 200, 250, 300, 33]
sorted(templist, key=int)               # ascending order
> [25, 33, 50, 100, 150, 200, 250, 300]
sorted(templist, key=int, reverse=True) # descending order
> [300, 250, 200, 150, 100, 50, 33, 25]

As has been pointed in the comments, the int key (or float if values with decimals are being stored) is required for correctly sorting the data if the data received is of type string, but it'd be very strange to store temperature values as strings, if that is the case, go back and fix the problem at the root, and make sure that the temperatures being stored are numbers.

Get array of object's keys

Of course, Object.keys() is the best way to get an Object's keys. If it's not available in your environment, it can be trivially shimmed using code such as in your example (except you'd need to take into account your loop will iterate over all properties up the prototype chain, unlike Object.keys()'s behaviour).

However, your example code...

var foo = { 'alpha' : 'puffin', 'beta' : 'beagle' };
var keys = [];
for (var key in foo) {
    keys.push(key);
}

jsFiddle.

...could be modified. You can do the assignment right in the variable part.

var foo = { 'alpha' : 'puffin', 'beta' : 'beagle' };
var keys = [], i = 0;
for (keys[i++] in foo) {}

jsFiddle.

Of course, this behaviour is different to what Object.keys() actually does (jsFiddle). You could simply use the shim on the MDN documentation.

Pythonic way to create a long multi-line string

For defining a long string inside a dict, keeping the newlines but omitting the spaces, I ended up defining the string in a constant like this:

LONG_STRING = \
"""
This is a long sting
that contains newlines.
The newlines are important.
"""

my_dict = {
   'foo': 'bar',
   'string': LONG_STRING
}

Refresh DataGridView when updating data source

Try this Code

List itemStates = new List();

for (int i = 0; i < 10; i++)
{ 
    itemStates.Add(new ItemState { Id = i.ToString() });
    dataGridView1.DataSource = itemStates;
    dataGridView1.DataBind();
    System.Threading.Thread.Sleep(500);
}

Open youtube video in Fancybox jquery

$("a.more").click(function() {
                 $.fancybox({
                  'padding'             : 0,
                  'autoScale'   : false,
                  'transitionIn'        : 'none',
                  'transitionOut'       : 'none',
                  'title'               : this.title,
                  'width'               : 680,
                  'height'              : 495,
                  'href'                : this.href.replace(new RegExp("watch\\?v=", "i"), 'v/'),
                  'type'                : 'swf',    // <--add a comma here
                  'swf'                 : {'allowfullscreen':'true'} // <-- flashvars here
                  });
                 return false;

            }); 

Angular2 equivalent of $document.ready()

the accepted answer is not correct, and it makes no sens to accept it considering the question

ngAfterViewInit will trigger when the DOM is ready

whine ngOnInit will trigger when the page component is only starting to be created

How do I set a checkbox in razor view?

you set AllowRating property to true from your controller or model

      @Html.CheckBoxFor(m => m.AllowRating, new { @checked =Model.AllowRating })

BACKUP LOG cannot be performed because there is no current database backup

I fixed my error on restoring to non-existing DB from SQL 2008 to SQL 2014 by putting a check mark on Relocating to the new SQL2014 folder location.

"The system cannot find the file C:\ProgramData\Oracle\Java\javapath\java.exe"

Why Oracle did such a poor way to point to java is beyond me. We solved this problem by creating a new link to the JDK

mklink /d C:\ProgramData\Oracle\Java\javapath "C:\Program Files\Java\jdk1.8.0_40\bin\"

The same would work for a JRE if that is all that is required.

This replaces the old symlinks in C:\ProgramData\Oracle\Java\javapath (if they existed previously)

What is the difference between resource and endpoint?

According https://apiblueprint.org/documentation/examples/13-named-endpoints.html is a resource a "general" place of storage of the given entity - e.g. /customers/30654/orders, whereas an endpoint is the concrete action (HTTP Method) over the given resource. So one resource can have multiple endpoints.

Replace preg_replace() e modifier with preg_replace_callback

In a regular expression, you can "capture" parts of the matched string with (brackets); in this case, you are capturing the (^|_) and ([a-z]) parts of the match. These are numbered starting at 1, so you have back-references 1 and 2. Match 0 is the whole matched string.

The /e modifier takes a replacement string, and substitutes backslash followed by a number (e.g. \1) with the appropriate back-reference - but because you're inside a string, you need to escape the backslash, so you get '\\1'. It then (effectively) runs eval to run the resulting string as though it was PHP code (which is why it's being deprecated, because it's easy to use eval in an insecure way).

The preg_replace_callback function instead takes a callback function and passes it an array containing the matched back-references. So where you would have written '\\1', you instead access element 1 of that parameter - e.g. if you have an anonymous function of the form function($matches) { ... }, the first back-reference is $matches[1] inside that function.

So a /e argument of

'do_stuff(\\1) . "and" . do_stuff(\\2)'

could become a callback of

function($m) { return do_stuff($m[1]) . "and" . do_stuff($m[2]); }

Or in your case

'strtoupper("\\2")'

could become

function($m) { return strtoupper($m[2]); }

Note that $m and $matches are not magic names, they're just the parameter name I gave when declaring my callback functions. Also, you don't have to pass an anonymous function, it could be a function name as a string, or something of the form array($object, $method), as with any callback in PHP, e.g.

function stuffy_callback($things) {
    return do_stuff($things[1]) . "and" . do_stuff($things[2]);
}
$foo = preg_replace_callback('/([a-z]+) and ([a-z]+)/', 'stuffy_callback', 'fish and chips');

As with any function, you can't access variables outside your callback (from the surrounding scope) by default. When using an anonymous function, you can use the use keyword to import the variables you need to access, as discussed in the PHP manual. e.g. if the old argument was

'do_stuff(\\1, $foo)'

then the new callback might look like

function($m) use ($foo) { return do_stuff($m[1], $foo); }

Gotchas

  • Use of preg_replace_callback is instead of the /e modifier on the regex, so you need to remove that flag from your "pattern" argument. So a pattern like /blah(.*)blah/mei would become /blah(.*)blah/mi.
  • The /e modifier used a variant of addslashes() internally on the arguments, so some replacements used stripslashes() to remove it; in most cases, you probably want to remove the call to stripslashes from your new callback.

POST Content-Length exceeds the limit

I disagree, but the solution to increase the file size in php.ini or .htaccess won't work if the user sends a file larger than allowed by the server application.

I suggest validating this on the front end. For example:

_x000D_
_x000D_
$(document).ready(function() {
    $ ('#your_input_file_id').bind('change', function() {
        var fileSize = this.files[0].size/1024/1024;
        if (fileSize > 2) { // 2M
            alert('Your custom message for max file size exceeded');
            $('#your_input_file_id').val('');
        }
    });
});
_x000D_
_x000D_
_x000D_

TortoiseSVN Error: "OPTIONS of 'https://...' could not connect to server (...)"

make sure when you add your proxy entries to the server file, you add them under the [global] group. (That seemed to make the difference for me under ubuntu.)

Best way to use PHP to encrypt and decrypt passwords?

Security warning: This code is not secure.

working example

define('SALT', 'whateveryouwant'); 

function encrypt($text) 
{ 
    return trim(base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, SALT, $text, MCRYPT_MODE_ECB, mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB), MCRYPT_RAND)))); 
} 

function decrypt($text) 
{ 
    return trim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, SALT, base64_decode($text), MCRYPT_MODE_ECB, mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB), MCRYPT_RAND))); 
} 

$encryptedmessage = encrypt("your message"); 
echo decrypt($encryptedmessage); 

Eclipse No tests found using JUnit 5 caused by NoClassDefFoundError for LauncherFactory

I am using eclipse 2019-09.

I had to update the junit-bom version to at least 5.4.0. I previously had 5.3.1 and that caused the same symptoms of the OP.

My config is now:

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.junit</groupId>
                <artifactId>junit-bom</artifactId>
                <version>5.5.2</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

Left/Right float button inside div

Change display:inline to display:inline-block

.test {
  width:200px;
  display:inline-block;
  overflow: auto;
  white-space: nowrap;
  margin:0px auto;
  border:1px red solid;
}

Installation error: INSTALL_FAILED_OLDER_SDK

I've changed my android:minSdkVersion and android:targetSdkVersion to 18 from 21:

uses-sdk android:minSdkVersion="18" android:targetSdkVersion="18" 

Now I can install my app successfully.

How to install ia32-libs in Ubuntu 14.04 LTS (Trusty Tahr)

A solution is add the corresponding Debian package way to your repository. For this, type the below commands:

echo "deb ftp.us.debian.org/debian wheezy main" >> /etc/apt/sources.list
sudo apt-get update
sudo apt-get install ia32-libs-i386

The first line writes in the end of the sources.list file the package way. This works for me. I wish that helps you.

Generic htaccess redirect www to non-www

Alternative approach if .htaccess customization is not ideal option:

I've created simple redirect server for public use. Just add A or CNAME record:

CNAME   r.simpleredirect.net
A       89.221.218.22

More info: https://simpleredirect.net

Copy Paste Values only( xlPasteValues )

You may use this too

Sub CopyPaste()
Sheet1.Range("A:A").Copy

Sheet2.Activate
col = 1
Do Until Sheet2.Cells(1, col) = ""
    col = col + 1
Loop

Sheet2.Cells(1, col).PasteSpecial xlPasteValues
End Sub

Image library for Python 3

As of March 30, 2012, I have tried and failed to get the sloonz fork on GitHub to open images. I got it to compile ok, but it didn't actually work. I also tried building gohlke's library, and it compiled also but failed to open any images. Someone mentioned PythonMagick above, but it only compiles on Windows. See PythonMagick on the wxPython wiki.

PIL was last updated in 2009, and while it's website says they are working on a Python 3 port, it's been 3 years, and the mailing list has gone cold.

To solve my Python 3 image manipulation problem, I am using subprocess.call() to execute ImageMagick shell commands. This method works.

See the subprocess module documentation.

Referring to a Column Alias in a WHERE Clause

The most effective way to do it without repeating your code is use of HAVING instead of WHERE

SELECT logcount, logUserID, maxlogtm
   , DATEDIFF(day, maxlogtm, GETDATE()) AS daysdiff
FROM statslogsummary
HAVING daysdiff > 120

How to compare two Carbon Timestamps?

First, convert the timestamp using the built-in eloquent functionality, as described in this answer.

Then you can just use Carbon's min() or max() function for comparison. For example:

$dt1 = Carbon::create(2012, 1, 1, 0, 0, 0); $dt2 = Carbon::create(2014, 1, 30, 0, 0, 0); echo $dt1->min($dt2);

This will echo the lesser of the two dates, which in this case is $dt1.

See http://carbon.nesbot.com/docs/

Create a hexadecimal colour based on a string with JavaScript

Here is another try:

function stringToColor(str){
  var hash = 0;
  for(var i=0; i < str.length; i++) {
    hash = str.charCodeAt(i) + ((hash << 3) - hash);
  }
  var color = Math.abs(hash).toString(16).substring(0, 6);

  return "#" + '000000'.substring(0, 6 - color.length) + color;
}

Left align and right align within div in Bootstrap

Bootstrap v4 introduces flexbox support

<div class="d-flex justify-content-end">
  <div class="mr-auto p-2">Flex item</div>
  <div class="p-2">Flex item</div>
  <div class="p-2">Flex item</div>
</div>

Learn more at https://v4-alpha.getbootstrap.com/utilities/flexbox/

TypeError: 'float' object is not subscriptable

You are not selecting multiple indexes with PriceList[0][1][2][3][4][5][6] , instead each [] is going into a sub index.

Try this

PizzaChange=float(input("What would you like the new price for all standard pizzas to be? "))      
PriceList[0:7]=[PizzaChange]*7  
PriceList[7:11]=[PizzaChange+3]*4

How can I de-install a Perl module installed via `cpan`?

Since at the time of installing of any module it mainly put corresponding .pm files in respective directories. So if you want to remove module only for some testing purpose or temporarily best is to find the path where module is stored using perldoc -l <MODULE> and then simply move the module from there to some other location. This approach can also be tried as a more permanent solution but i am not aware of any negative consequences as i do it mainly for testing.

What exactly is the difference between Web API and REST API in MVC?

I have been there, like so many of us. There are so many confusing words like Web API, REST, RESTful, HTTP, SOAP, WCF, Web Services... and many more around this topic. But I am going to give brief explanation of only those which you have asked.

REST

It is neither an API nor a framework. It is just an architectural concept. You can find more details here.

RESTful

I have not come across any formal definition of RESTful anywhere. I believe it is just another buzzword for APIs to say if they comply with REST specifications.

EDIT: There is another trending open source initiative OpenAPI Specification (OAS) (formerly known as Swagger) to standardise REST APIs.

Web API

It in an open source framework for writing HTTP APIs. These APIs can be RESTful or not. Most HTTP APIs we write are not RESTful. This framework implements HTTP protocol specification and hence you hear terms like URIs, request/response headers, caching, versioning, various content types(formats).

Note: I have not used the term Web Services deliberately because it is a confusing term to use. Some people use this as a generic concept, I preferred to call them HTTP APIs. There is an actual framework named 'Web Services' by Microsoft like Web API. However it implements another protocol called SOAP.

Why would $_FILES be empty when uploading files to PHP?

Here's a check-list for file uploading in PHP:

  1. Check php.ini for:
    file_uploads = On
    post_max_size = 100M
    upload_max_filesize = 100M

    • You might need to use .htaccess or .user.ini if you are on shared hosting and don't have access to php.ini.
    • Make sure you’re editing the correct ini file – use the phpinfo() function to verify your settings are actually being applied.
    • Also make sure you don’t misspell the sizes - it should be 100M not 100MB.
  2. Make sure your <form> tag has the enctype="multipart/form-data" attribute. No other tag will work, it has to be your FORM tag. Double check that it is spelled correctly. Double check that multipart/form-data is surrounded by STRAIGHT QUOTES, not smart quotes pasted in from Word OR from a website blog (WordPress converts straight quotes to angle quotes!). If you have multiple forms on the page, make sure they both have this attribute. Type them in manually, or try straight single quotes typed in manually.

  3. Make sure you do not have two input file fields with the same name attribute. If you need to support multiple, put square brackets at the end of the name:

    <input type="file" name="files[]">
    <input type="file" name="files[]">
    
  4. Make sure your tmp and upload directories have the correct read+write permissions set. The temporary upload folder is specified in PHP settings as upload_tmp_dir.

  5. Make sure your file destination and tmp/upload directories do not have spaces in them.

  6. Make sure all <form>'s on your page have </form> close tags.

  7. Make sure your FORM tag has method="POST". GET requests do not support multipart/form-data uploads.

  8. Make sure your file input tag has a NAME attribute. An ID attribute is NOT sufficient! ID attributes are for use in the DOM, not for POST payloads.

  9. Make sure you are not using Javascript to disable your <input type="file"> field on submission

  10. Make sure you're not nesting forms like <form><form></form></form>

  11. Check your HTML structure for invalid/overlapping tags like <div><form></div></form>

  12. Also make sure that the file you are uploading does not have any non-alphanumeric characters in it.

  13. Once, I just spent hours trying to figure out why this was happening to me all of a sudden. It turned out that I had modified some of the PHP settings in .htaccess, and one of them (not sure which yet) was causing the upload to fail and $_FILES to be empty.

  14. You could potentially try avoiding underscores (_) in the name="" attribute of the <input> tag

  15. Try uploading very small files to narrow down whether it's a file-size issue.

  16. Check your available disk space. Although very rare, it is mentioned in this PHP Manual page comment:

    If the $_FILES array suddenly goes mysteriously empty, even though your form seems correct, you should check the disk space available for your temporary folder partition. In my installation, all file uploads failed without warning. After much gnashing of teeth, I tried freeing up additional space, after which file uploads suddenly worked again.

  17. Be sure that you're not submitting the form through an AJAX POST request instead of a normal POST request that causes a page to reload. I went through each and every point in the list above, and finally found out that the reason due to which my $_FILES variable was empty was that I was submitting the form using an AJAX POST request. I know that there are methods to upload files using ajax too, but this could be a valid reason why your $_FILES array is empty.

Source for some of these points:
http://getluky.net/2004/10/04/apachephp-_files-array-mysteriously-empty/

Convert DateTime to long and also the other way around

There are several possibilities (note that the those long values aren't the same as the Unix epoch.

For your example (to reverse ToFileTime()) just use DateTime.FromFileTime(t).

Nginx 403 error: directory index of [folder] is forbidden

change the try_files to point to the index.php path, in the "Laravel" that you mentioned it should be something like this

location / {
    try_files $uri $uri/ /public/index.php$request_uri;
}

And in the "codeigniter" project try it like this

location / {
    try_files $uri $uri/ /public_web/index.php$request_uri;
}

Array copy values to keys in PHP

Be careful, the solution proposed with $a = array_combine($a, $a); will not work for numeric values.

I for example wanted to have a memory array(128,256,512,1024,2048,4096,8192,16384) to be the keys as well as the values however PHP manual states:

If the input arrays have the same string keys, then the later value for that key will overwrite the previous one. If, however, the arrays contain numeric keys, the later value will not overwrite the original value, but will be appended.

So I solved it like this:

foreach($array as $key => $val) {
    $new_array[$val]=$val;
}

Hidden features of Python

Combine unpacking with the print function:

# in 2.6 <= python < 3.0, 3.0 + the print function is native
from __future__ import print_function 

mylist = ['foo', 'bar', 'some other value', 1,2,3,4]  
print(*mylist)

How to play YouTube video in my Android application?

Google has a YouTube Android Player API that enables you to incorporate video playback functionality into your Android applications. The API itself is very easy to use and works well. For example, here is how to create a new activity to play a video using the API.

Intent intent = YouTubeStandalonePlayer.createVideoIntent(this, "<<YOUTUBE_API_KEY>>", "<<Youtube Video ID>>", 0, true, false);   
startActivity(intent);

See this for more details.

How to list AD group membership for AD users using input list?

Everything in one line:

get-aduser -filter * -Properties memberof | select name, @{ l="GroupMembership"; e={$_.memberof  -join ";"  } } | export-csv membership.csv

Query EC2 tags from within instance

Install AWS CLI:

curl "https://s3.amazonaws.com/aws-cli/awscli-bundle.zip" -o "awscli-bundle.zip"
sudo apt-get install unzip
unzip awscli-bundle.zip
sudo ./awscli-bundle/install -i /usr/local/aws -b /usr/local/bin/aws

Get the tags for the current instance:

aws ec2 describe-tags --filters "Name=resource-id,Values=`ec2metadata --instance-id`"

Outputs:

{
    "Tags": [
        {
            "ResourceType": "instance", 
            "ResourceId": "i-6a7e559d", 
            "Value": "Webserver", 
            "Key": "Name"
        }
    ]
}

Use a bit of perl to extract the tags:

aws ec2 describe-tags --filters \
"Name=resource-id,Values=`ec2metadata --instance-id`" | \
perl -ne 'print "$1\n" if /\"Value\": \"(.*?)\"/'

Returns:

Webserver

How to write console output to a txt file

Create the following method:

public class Logger {
    public static void log(String message) { 
      PrintWriter out = new PrintWriter(new FileWriter("output.txt", true), true);
      out.write(message);
      out.close();
    }
}

(I haven't included the proper IO handling in the above class, and it won't compile - do it yourself. Also consider configuring the file name. Note the "true" argument. This means the file will not be re-created each time you call the method)

Then instead of System.out.println(str) call Logger.log(str)

This manual approach is not preferable. Use a logging framework - slf4j, log4j, commons-logging, and many more

get list of packages installed in Anaconda

To list all of the packages in the active environment, use:

conda list

To list all of the packages in a deactivated environment, use:

conda list -n myenv

How to change the href for a hyperlink using jQuery

This snippet invokes when a link of class 'menu_link' is clicked, and shows the text and url of the link. The return false prevents the link from being followed.

<a rel='1' class="menu_link" href="option1.html">Option 1</a>
<a rel='2' class="menu_link" href="option2.html">Option 2</a>

$('.menu_link').live('click', function() {
   var thelink = $(this);
   alert ( thelink.html() );
   alert ( thelink.attr('href') );
   alert ( thelink.attr('rel') );

   return false;
});

Toad for Oracle..How to execute multiple statements?

begin

insert into fiscal_year values(2001,'01-jan-2001','31-dec-2001');
insert into fiscal_year values(2002,'01-jan-2002','31-dec-2002');
insert into fiscal_year values(2003,'01-jan-2003','31-dec-2003');
insert into fiscal_year values(2004,'01-jan-2004','31-dec-2004');

end;

Use like this and then commit.

How to get a list of sub-folders and their files, ordered by folder-names

In command prompt go to the main directory you want the list for ... and type the command tree /f

jQuery selector for inputs with square brackets in the name attribute

Per the jQuery documentation, try this:

$('input[inputName\\[\\]=someValue]')

[EDIT] However, I'm not sure that's the right syntax for your selector. You probably want:

$('input[name="inputName[]"][value="someValue"]')

How can I render a list select box (dropdown) with bootstrap?

Another option could be using bootstrap select. On their own words:

A custom select / multiselect for Bootstrap using button dropdown, designed to behave like regular Bootstrap selects.

OS X Terminal UTF-8 issues

The following is a summary of what you need to do under OS X Mavericks (10.9). This is all summarized in

http://hints.macworld.com/article.php?story=20060825071728278

  1. Go to Terminal->Preferences->Settings->Advanced.

    Under International, make sure the character encoding is set to Unicode (UTF-8).

    Also, and this is key: under Emulation, make sure that Escape non-ASCII input with Control-V is unchecked (i.e. is not set).

    These two settings fix things for Terminal.

  2. Make sure your locale is set to something that ends in .UTF-8. Type locale and look at the LC_CTYPE line. If it doesn't say something like en_US.UTF-8 (the stuff before the dot might change if you are using a non-US-English locale), then in your Bash .profile or .bashrc in your home directory, add a line like this:

    export LC_CTYPE=en_US.UTF-8
    

    This will fix things for command-line programs in general.

  3. Add the following lines to .inputrc in your home directory (create it if necessary):

    set meta-flag on
    set input-meta on
    set output-meta on
    set convert-meta off
    

    This makes Bash be eight-bit clean, so it will pass UTF-8 characters in and out without messing with them.

Keep in mind you will have to restart Bash (e.g. close and reopen the Terminal window) to get it to pay attention to all the settings you make in 2 and 3 above.

How can I make a button have a rounded border in Swift?

TRY THIS Button Border With Rounded Corners

anyButton.backgroundColor = .clear

anyButton.layer.cornerRadius = anyButton.frame.height / 2

anyButton.layer.borderWidth = 1

anyButton.layer.borderColor = UIColor.black.cgColor

How to find the UpgradeCode and ProductCode of an installed application in Windows 7

Another way-too-complicated workaround, with the benefit of not having to re-install the application as the previous workaround required. This requires that you have access to the msi (or a setup.exe with the msi embedded).

If you have Visual Studio 2012 (or possibly other editions) and install the free "InstallShield LE", then you can create a new setup project using InstallShield.

One of the configuration options in the "Organize your Setup" step is called "Upgrade Paths". Open the properties for Upgrade Paths, and in the left pane right click "Upgrade Paths" and select "New Upgrade Path" ... now browse to the msi (or setup.exe containing the msi) and click "open". The upgrade code will be populated for you in the settings page in the right pane which you should now see.

Find out the history of SQL queries

You can use this sql statement to get the history for any date:

SELECT * FROM V$SQL V where  to_date(v.FIRST_LOAD_TIME,'YYYY-MM-DD hh24:mi:ss') > sysdate - 60

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

In my case I wanted to manually add urlrewrite rule and couldn't see the obvious error (I missed <rules> tag):

wrong code:

    <rewrite>
      <rule name="some rule" stopProcessing="true">
        <match url="some-pattenr/(.*)" />        
        <action type="Redirect" url="/some-ne-pattenr/{R:1}" />
      </rule>
    </rewrite>    

  </system.webServer>
</configuration>

proper code (with rules tag):

    <rewrite>
      <rules>
        <rule name="some rule" stopProcessing="true">
          <match url="some-pattenr/(.*)" />        
          <action type="Redirect" url="/some-ne-pattenr/{R:1}" />
        </rule>
      </rules>
    </rewrite>

  </system.webServer>
</configuration>

How do I delete multiple rows with different IDs?

Disclaim: the following suggestion could be an overhead depending on the situation. The function is only tested with MSSQL 2008 R2 but seams be compatible to other versions

if you wane do this with many Id's you may could use a function which creates a temp table where you will be able to DELETE FROM the selection

how the query could look like:

-- not tested
-- @ids will contain a varchar with your ids e.g.'9 12 27 37'
DELETE FROM table WHERE id IN (SELECT i.number FROM iter_intlist_to_tbl(@ids))

here is the function:

ALTER FUNCTION iter_intlist_to_tbl (@list nvarchar(MAX))
   RETURNS @tbl TABLE (listpos int IDENTITY(1, 1) NOT NULL,
                       number  int NOT NULL) AS

   -- funktion gefunden auf http://www.sommarskog.se/arrays-in-sql-2005.html
   -- dient zum übergeben einer liste von elementen

BEGIN
    -- Deklaration der Variablen
    DECLARE @startpos int,
            @endpos   int,
            @textpos  int,
            @chunklen smallint,
            @str      nvarchar(4000),
            @tmpstr   nvarchar(4000),
            @leftover nvarchar(4000)

    -- Startwerte festlegen
   SET @textpos = 1
   SET @leftover = ''

   -- Loop 1
    WHILE @textpos <= datalength(@list) / 2
    BEGIN

        --
        SET @chunklen = 4000 - datalength(@leftover) / 2 --datalength() gibt die anzahl der bytes zurück (mit Leerzeichen)

        --
        SET @tmpstr = ltrim(@leftover + substring(@list, @textpos, @chunklen))--SUBSTRING ( @string ,start , length ) | ltrim(@string) abschneiden aller Leerzeichen am Begin des Strings

        --hochzählen der TestPosition
        SET @textpos = @textpos + @chunklen

        --start position 0 setzen
        SET @startpos = 0

        -- end position bekommt den charindex wo ein [LEERZEICHEN] gefunden wird
        SET @endpos = charindex(' ' COLLATE Slovenian_BIN2, @tmpstr)--charindex(searchChar,Wo,Startposition)

        -- Loop 2
        WHILE @endpos > 0
        BEGIN
            --str ist der string welcher zwischen den [LEERZEICHEN] steht
            SET @str = substring(@tmpstr, @startpos + 1, @endpos - @startpos - 1) 

            --wenn @str nicht leer ist wird er zu int Convertiert und @tbl unter der Spalte 'number' hinzugefügt
            IF @str <> ''
                INSERT @tbl (number) VALUES(convert(int, @str))-- convert(Ziel-Type,Value)

            -- start wird auf das letzte bekannte end gesetzt
            SET @startpos = @endpos

            -- end position bekommt den charindex wo ein [LEERZEICHEN] gefunden wird
            SET @endpos = charindex(' ' COLLATE Slovenian_BIN2, @tmpstr, @startpos + 1)
        END
        -- Loop 2

        -- dient dafür den letzten teil des strings zu selektieren
        SET @leftover = right(@tmpstr, datalength(@tmpstr) / 2 - @startpos)--right(@string,anzahl der Zeichen) bsp.: right("abcdef",3) => "def"
    END
    -- Loop 1

    --wenn @leftover nach dem entfernen aller [LEERZEICHEN] nicht leer ist wird er zu int Convertiert und @tbl unter der Spalte 'number' hinzugefügt
    IF ltrim(rtrim(@leftover)) <> ''
        INSERT @tbl (number) VALUES(convert(int, @leftover))

    RETURN
END


    -- ############################ WICHTIG ############################
    -- das is ein Beispiel wie man die Funktion benutzt
    --
    --CREATE    PROCEDURE get_product_names_iter 
    --      @ids varchar(50) AS
    --SELECT    P.ProductName, P.ProductID
    --FROM      Northwind.Products P
    --JOIN      iter_intlist_to_tbl(@ids) i ON P.ProductID = i.number
    --go
    --EXEC get_product_names_iter '9 12 27 37'
    --
    -- Funktion gefunden auf http://www.sommarskog.se/arrays-in-sql-2005.html
    -- dient zum übergeben einer Liste von Id's
    -- ############################ WICHTIG ############################

npm can't find package.json

try re-install Node.js

curl -sL https://deb.nodesource.com/setup_4.x | sudo -E bash -

sudo apt-get install -y nodejs

sudo apt-get install -y build-essential

and update npm

curl -L https://npmjs.com/install.sh | sudo sh

Check that a variable is a number in UNIX shell

if echo $var | egrep -q '^[0-9]+$'; then
    # $var is a number
else
    # $var is not a number
fi

How to extract public key using OpenSSL?

openssl rsa -in privkey.pem -pubout > key.pub

That writes the public key to key.pub

UICollectionView - Horizontal scroll, horizontal layout?

You need to reduce the height of UICollectionView to its cell / item height and select "Horizontal" from the "Scroll Direction" as seen in the screenshot below. Then it will scroll horizontally depending on the numberOfItems you have returned in its datasource implementation.

enter image description here

Fastest way to get the first object from a queryset in django?

It can be like this

obj = model.objects.filter(id=emp_id)[0]

or

obj = model.objects.latest('id')

How can I convert a hex string to a byte array?

I think this may work.

public static byte[] StrToByteArray(string str)
    {
        Dictionary<string, byte> hexindex = new Dictionary<string, byte>();
        for (int i = 0; i <= 255; i++)
            hexindex.Add(i.ToString("X2"), (byte)i);

        List<byte> hexres = new List<byte>();
        for (int i = 0; i < str.Length; i += 2)            
            hexres.Add(hexindex[str.Substring(i, 2)]);

        return hexres.ToArray();
    }

How to remove an appended element with Jquery and why bind or live is causing elements to repeat

If I understand your question correctly, I've made a fiddle that has this working correctly. This issue is with how you're assigning the event handlers and as others have said you have over riding event handlers. The current jQuery best practice is to use on() to register event handlers. Here's a link to the jQuery docs about on: link

Your original solution was pretty close but the way you added the event handlers is a bit confusing. It's considered best practice to not add events to HTML elements. I recommend reading up on Unobstrusive JavaScript.

Here's the JavaScript code. I added a counter variable so you can see that it is working correctly.

$('#answer').on('click', function() {
  feedback('hey there');
});

var counter = 0;

function feedback(message) {

  $('#feedback').remove();

  $('.answers').append('<div id="feedback">' + message + ' ' + counter + '</div>');

  counter++;    
}

Merge two objects with ES6

Another aproach is:

let result = { ...item, location : { ...response } }

But Object spread isn't yet standardized.

May also be helpful: https://stackoverflow.com/a/32926019/5341953

How can you test if an object has a specific property?

I recently switch to set strict-mode -version 2.0 and my null tests failed.

I added a function:

#use in strict mode to validate property exists before using
function exists {
  param($obj,$prop)
  try {
    if ($null -ne $obj[$prop]) {return $true}
    return $false
  } catch {
    return $false
  }
  return $false
}

Now I code

if (exists $run main) { ...

rather than

if ($run.main -ne $null) { ...

and we are on our way. Seems to work on objects and hashtables

As an unintended benefit it is less typing.

Understanding Fragment's setRetainInstance(boolean)

setRetainInstance() - Deprecated

As Fragments Version 1.3.0-alpha01

The setRetainInstance() method on Fragments has been deprecated. With the introduction of ViewModels, developers have a specific API for retaining state that can be associated with Activities, Fragments, and Navigation graphs. This allows developers to use a normal, not retained Fragment and keep the specific state they want retained separate, avoiding a common source of leaks while maintaining the useful properties of a single creation and destruction of the retained state (namely, the constructor of the ViewModel and the onCleared() callback it receives).

How to print a date in a regular format?

Here is how to display the date as (year/month/day) :

from datetime import datetime
now = datetime.now()

print '%s/%s/%s' % (now.year, now.month, now.day)

How to implement a ConfigurationSection with a ConfigurationElementCollection

Try inheriting from ConfigurationSection. This blog post by Phil Haack has an example.

Confirmed, per the documentation for IConfigurationSectionHandler:

In .NET Framework version 2.0 and above, you must instead derive from the ConfigurationSection class to implement the related configuration section handler.

How generate unique Integers based on GUIDs

A GUID is a 128 bit integer (its just in hex rather than base 10). With .NET 4 use http://msdn.microsoft.com/en-us/library/dd268285%28v=VS.100%29.aspx like so:

// Turn a GUID into a string and strip out the '-' characters.
BigInteger huge = BigInteger.Parse(modifiedGuidString, NumberStyles.AllowHexSpecifier)

If you don't have .NET 4 you can look at IntX or Solver Foundation.

Retrieving data from a POST method in ASP.NET

The data from the request (content, inputs, files, querystring values) is all on this object HttpContext.Current.Request
To read the posted content

StreamReader reader = new StreamReader(HttpContext.Current.Request.InputStream);
string requestFromPost = reader.ReadToEnd();

To navigate through the all inputs

foreach (string key in HttpContext.Current.Request.Form.AllKeys)
{
   string value = HttpContext.Current.Request.Form[key];
}

Chart.js v2 - hiding grid lines

OK, nevermind.. I found the trick:

    scales: {
      yAxes: [
        {
          gridLines: {
                lineWidth: 0
            }
        }
      ]
    }

Java regular expression OR operator

You can just use the pipe on its own:

"string1|string2"

for example:

String s = "string1, string2, string3";
System.out.println(s.replaceAll("string1|string2", "blah"));

Output:

blah, blah, string3

The main reason to use parentheses is to limit the scope of the alternatives:

String s = "string1, string2, string3";
System.out.println(s.replaceAll("string(1|2)", "blah"));

has the same output. but if you just do this:

String s = "string1, string2, string3";
System.out.println(s.replaceAll("string1|2", "blah"));

you get:

blah, stringblah, string3

because you've said "string1" or "2".

If you don't want to capture that part of the expression use ?::

String s = "string1, string2, string3";
System.out.println(s.replaceAll("string(?:1|2)", "blah"));

Compare two MySQL databases

There is a useful tool written using perl called Maatkit. It has several database comparison and syncing tools among other things.

Edit Crystal report file without Crystal Report software

This may be a long shot, but Crystal Reports for Eclipse is free. I'm not sure if it will work, but if all you need is to edit some static text, you could get that version of CR and get the job done.

How do I remove link underlining in my HTML email?

I see this has been answered; however, I feel this link provides appropriate information for what formatting is supported in various email clients.

http://www.campaignmonitor.com/css/

It's worth noting that GMail and Outlook are two of the pickiest to format HTML email for.

Collection was modified; enumeration operation may not execute

Okay so what helped me was iterating backwards. I was trying to remove an entry from a list but iterating upwards and it screwed up the loop because the entry didn't exist anymore:

for (int x = myList.Count - 1; x > -1; x--)
{
    myList.RemoveAt(x);
}

What determines the monitor my app runs on?

It's not exactly the answer to this question but I dealt with this problem with the Shift + Win + [left,right] arrow keys shortcut. You can move the currently active window to another monitor with it.

typesafe select onChange event using reactjs and typescript

In my case onChange event was typed as React.ChangeEvent:

onChange={ (e: React.ChangeEvent<HTMLSelectElement>) => {
           console.warn('onChange TextInput value: ' + e.target.value);
           } 
         }

How to add new elements to an array?

There is no method append() on arrays. Instead as already suggested a List object can service the need for dynamically inserting elements eg.

List<String> where = new ArrayList<String>();
where.add(ContactsContract.Contacts.HAS_PHONE_NUMBER + "=1");
where.add(ContactsContract.Contacts.IN_VISIBLE_GROUP + "=1");

Or if you are really keen to use an array:

String[] where = new String[]{
    ContactsContract.Contacts.HAS_PHONE_NUMBER + "=1",
    ContactsContract.Contacts.IN_VISIBLE_GROUP + "=1"
};

but then this is a fixed size and no elements can be added.

Run Python script at startup in Ubuntu

Put this in /etc/init (Use /etc/systemd in Ubuntu 15.x)

mystartupscript.conf

start on runlevel [2345]
stop on runlevel [!2345]

exec /path/to/script.py

By placing this conf file there you hook into ubuntu's upstart service that runs services on startup.

manual starting/stopping is done with sudo service mystartupscript start and sudo service mystartupscript stop

Assign an initial value to radio button as checked

If you are using react-redux for your application and if you want to show data which is in the redux store, you can set "checked" option as below.

<label>Male</label>

 <input
   type="radio"
   name="gender"
   defaultChecked={this.props.gender == "0"}
 />



 <label>Female</label>
 <input
   type="radio"
   name="gender"
   defaultChecked={this.props.gender == "1"}
 />

Spring Could not Resolve placeholder

If your config file is in a different path than classpath, you can add the configuration file path as a system property:

java -Dapp.config.path=path_to_config_file -jar your.jar

How do I install a custom font on an HTML site

Try this

_x000D_
_x000D_
@font-face {  _x000D_
    src: url(fonts/Market_vilis.ttf) format("truetype");_x000D_
}_x000D_
div.FontMarket { _x000D_
    font-family:  Market Deco;_x000D_
}
_x000D_
 <div class="FontMarket">KhonKaen Market</div>
_x000D_
_x000D_
_x000D_

vilis.org

How to open a workbook specifying its path

You can also open a required file through a prompt, This helps when you want to select file from different path and different file.

Sub openwb()
Dim wkbk As Workbook
Dim NewFile As Variant

NewFile = Application.GetOpenFilename("microsoft excel files (*.xlsm*), *.xlsm*")

If NewFile <> False Then
Set wkbk = Workbooks.Open(NewFile)
End If
End Sub

How to position background image in bottom right corner? (CSS)

Did you try something like:

body {background: url('[url to your image]') no-repeat right bottom;}

How can I get the current page name in WordPress?

I have come up with a simpler solution.

Get the returned value of the page name from wp_title(). If empty, print homepage name, otherwise echo the wp_title() value.

<?php $title = wp_title('', false); ?>

Remember to remove the separation with the first argument and then set display to false to use as an input to the variable. Then just bung the code between your heading, etc. tags.

<?php if ( $title == "" ) : echo "Home"; else : echo $title; endif; ?>

It worked a treat for me and ensuring that the first is declared in the section where you wish to extract the $title, this can be tuned to return different variables.

CFLAGS vs CPPFLAGS

The CPPFLAGS macro is the one to use to specify #include directories.

Both CPPFLAGS and CFLAGS work in your case because the make(1) rule combines both preprocessing and compiling in one command (so both macros are used in the command).

You don't need to specify . as an include-directory if you use the form #include "...". You also don't need to specify the standard compiler include directory. You do need to specify all other include-directories.

Where can I download english dictionary database in a text format?

The Gutenberg Project hosts Webster's Unabridged English Dictionary plus many other public domain literary works. Actually it looks like they've got several versions of the dictionary hosted with copyright from different years. The one I linked has a 2009 copyright. You may want to poke around the site and investigate the different versions of Webster's dictionary.

Environment variable substitution in sed

Dealing with VARIABLES within sed

[root@gislab00207 ldom]# echo domainname: None > /tmp/1.txt

[root@gislab00207 ldom]# cat /tmp/1.txt

domainname: None

[root@gislab00207 ldom]# echo ${DOMAIN_NAME}

dcsw-79-98vm.us.oracle.com

[root@gislab00207 ldom]# cat /tmp/1.txt | sed -e 's/domainname: None/domainname: ${DOMAIN_NAME}/g'

 --- Below is the result -- very funny.

domainname: ${DOMAIN_NAME}

 --- You need to single quote your variable like this ... 

[root@gislab00207 ldom]# cat /tmp/1.txt | sed -e 's/domainname: None/domainname: '${DOMAIN_NAME}'/g'


--- The right result is below 

domainname: dcsw-79-98vm.us.oracle.com

How to quickly check if folder is empty (.NET)?

You could try Directory.Exists(path) and Directory.GetFiles(path) - probably less overhead (no objects - just strings etc).

How can I make an image transparent on Android?

On newer versions of Android (post Android 4.2 (Jelly Bean) at least), the setAlpha(int value) method is depreciated. Instead, use the setAlpha(float value) method that takes a float between 0 and 1 where 0 is complete transparency and 1 is no transparency.

Install specific version using laravel installer

you can find all version install code here by changing the version of laravel doc

composer create-project --prefer-dist laravel/laravel yourProjectName "5.1.*"

above code for creating laravel 5.1 version project. see more in laravel doc. happy coding!!

Setting up a git remote origin

For anyone who comes here, as I did, looking for the syntax to change origin to a different location you can find that documentation here: https://help.github.com/articles/changing-a-remote-s-url/. Using git remote add to do this will result in "fatal: remote origin already exists."

Nutshell: git remote set-url origin https://github.com/username/repo

(The marked answer is correct, I'm just hoping to help anyone as lost as I was... haha)

How to backup Sql Database Programmatically in C#

I have new method without SMO problems

1. Create .bat File with backup sqlcmd command

for backup

SqlCmd -E -S Server_Name –Q “BACKUP DATABASE [Name_of_Database] TO DISK=’X:PathToBackupLocation[Name_of_Database].bak'”

for restore

SqlCmd -E -S Server_Name –Q “RESTORE DATABASE [Name_of_Database] FROM DISK=’X:PathToBackupFile[File_Name].bak'”

2. Run the the bat file with WPF/C# code

        FileInfo file = new FileInfo("DB\\batfile.bat");
        Process process = new Process();
        process.StartInfo.FileName = file.FullName;
        process.StartInfo.Arguments = @"-X";
        process.StartInfo.WindowStyle = ProcessWindowStyle.Normal;
        process.StartInfo.UseShellExecute = false; //Changed Line
        process.StartInfo.RedirectStandardOutput = true;  //Changed Line
        process.Start();
        string output = process.StandardOutput.ReadToEnd(); //Changed Line
        process.WaitForExit(); //Moved Line

Cannot use string offset as an array in php

I was able to reproduce this once I upgraded to PHP 7. It breaks when you try to force array elements into a string.

$params = '';
foreach ($foo) {
  $index = 0;
  $params[$index]['keyName'] = $name . '.' . $fileExt;
}

After changing:

$params = '';

to:

$params = array();

I stopped getting the error. I found the solution in this bug report thread. I hope this helps.

Why is my CSS style not being applied?

Posting, since it might be useful for someone in the future:

For me, when I got here, the solution was browser cache. Had to hard refresh Chrome (cmd/ctrl+shift+R) to get the new styles applied, it seems the old ones got cached really "deep".

This question/answer might come in handy for someone. And hard refresh tips for different browsers for those who don't use Chrome.

JSON.Net Self referencing loop detected

If using ASP.NET Core MVC, add this to the ConfigureServices method of your startup.cs file:

services.AddMvc()
    .AddJsonOptions(
        options => options.SerializerSettings.ReferenceLoopHandling =            
        Newtonsoft.Json.ReferenceLoopHandling.Ignore
    );

Official way to ask jQuery wait for all images to load before executing something

With jQuery i come with this...

$(function() {
    var $img = $('img'),
        totalImg = $img.length;

    var waitImgDone = function() {
        totalImg--;
        if (!totalImg) alert("Images loaded!");
    };

    $('img').each(function() {
        $(this)
            .load(waitImgDone)
            .error(waitImgDone);
    });
});

Demo : http://jsfiddle.net/molokoloco/NWjDb/

How to Serialize a list in java?

List is just an interface. The question is: is your actual List implementation serializable? Speaking about the standard List implementations (ArrayList, LinkedList) from the Java run-time, most of them actually are already.

Are HTTP headers case-sensitive?

header('Content-type: image/png') did not work with PHP 5.5 serving IE11, as in the image stream was shown as text

header('Content-Type: image/png') worked, as in the image appeared as an image

Only difference is the capital 'T'.

pandas read_csv index_col=None not working with delimiters at the end of each line

Re: craigts's response, for anyone having trouble with using either False or None parameters for index_col, such as in cases where you're trying to get rid of a range index, you can instead use an integer to specify the column you want to use as the index. For example:

df = pd.read_csv('file.csv', index_col=0)

The above will set the first column as the index (and not add a range index in my "common case").

Update

Given the popularity of this answer, I thought i'd add some context/ a demo:

# Setting up the dummy data
In [1]: df = pd.DataFrame({"A":[1, 2, 3], "B":[4, 5, 6]})

In [2]: df
Out[2]:
   A  B
0  1  4
1  2  5
2  3  6

In [3]: df.to_csv('file.csv', index=None)
File[3]:
A  B
1  4
2  5
3  6

Reading without index_col or with None/False will all result in a range index:

In [4]: pd.read_csv('file.csv')
Out[4]:
   A  B
0  1  4
1  2  5
2  3  6

# Note that this is the default behavior, so the same as In [4]
In [5]: pd.read_csv('file.csv', index_col=None)
Out[5]:
   A  B
0  1  4
1  2  5
2  3  6

In [6]: pd.read_csv('file.csv', index_col=False)
Out[6]:
   A  B
0  1  4
1  2  5
2  3  6

However, if we specify that "A" (the 0th column) is actually the index, we can avoid the range index:

In [7]: pd.read_csv('file.csv', index_col=0)
Out[7]:
   B
A
1  4
2  5
3  6

Find max and second max salary for a employee table MySQL

Here change n value according your requirement:

SELECT top 1 amount 
FROM ( 
    SELECT DISTINCT top n amount 
    FROM payment 
    ORDER BY amount DESC ) AS temp 
ORDER BY amount

How to disable manual input for JQuery UI Datepicker field?

When you make the input, set it to be readonly.

<input type="text" name="datepicker" id="datepicker" readonly="readonly" />

Bash: Echoing a echo command with a variable in bash

The immediate problem is you have is with quoting: by using double quotes ("..."), your variable references are instantly expanded, which is probably not what you want.

Use single quotes instead - strings inside single quotes are not expanded or interpreted in any way by the shell.

(If you want selective expansion inside a string - i.e., expand some variable references, but not others - do use double quotes, but prefix the $ of references you do not want expanded with \; e.g., \$var).

However, you're better off using a single here-doc[ument], which allows you to create multi-line stdin input on the spot, bracketed by two instances of a self-chosen delimiter, the opening one prefixed by <<, and the closing one on a line by itself - starting at the very first column; search for Here Documents in man bash or at http://www.gnu.org/software/bash/manual/html_node/Redirections.html.

If you quote the here-doc delimiter (EOF in the code below), variable references are also not expanded. As @chepner points out, you're free to choose the method of quoting in this case: enclose the delimiter in single quotes or double quotes, or even simply arbitrarily escape one character in the delimiter with \:

echo "creating new script file."

cat <<'EOF'  > "$servfile"
#!/bin/bash
read -p "Please enter a service: " ser
servicetest=`getsebool -a | grep ${ser}` 
if [ $servicetest > /dev/null ]; then 
  echo "we are now going to work with ${ser}"
else
  exit 1
fi
EOF

As @BruceK notes, you can prefix your here-doc delimiter with - (applied to this example: <<-"EOF") in order to have leading tabs stripped, allowing for indentation that makes the actual content of the here-doc easier to discern. Note, however, that this only works with actual tab characters, not leading spaces.

Employing this technique combined with the afterthoughts regarding the script's content below, we get (again, note that actual tab chars. must be used to lead each here-doc content line for them to get stripped):

cat <<-'EOF' > "$servfile"
    #!/bin/bash
    read -p "Please enter a service name: " ser
    if [[ -n $(getsebool -a | grep "${ser}") ]]; then 
      echo "We are now going to work with ${ser}."
    else
      exit 1
    fi
EOF

Finally, note that in bash even normal single- or double-quoted strings can span multiple lines, but you won't get the benefits of tab-stripping or line-block scoping, as everything inside the quotes becomes part of the string.

Thus, note how in the following #!/bin/bash has to follow the opening ' immediately in order to become the first line of output:

echo '#!/bin/bash
read -p "Please enter a service: " ser
servicetest=$(getsebool -a | grep "${ser}")
if [[ -n $servicetest ]]; then 
  echo "we are now going to work with ${ser}"
else
  exit 1
fi' > "$servfile"

Afterthoughts regarding the contents of your script:

  • The syntax $(...) is preferred over `...` for command substitution nowadays.
  • You should double-quote ${ser} in the grep command, as the command will likely break if the value contains embedded spaces (alternatively, make sure that the valued read contains no spaces or other shell metacharacters).
  • Use [[ -n $servicetest ]] to test whether $servicetest is empty (or perform the command substitution directly inside the conditional) - [[ ... ]] - the preferred form in bash - protects you from breaking the conditional if the $servicetest happens to have embedded spaces; there's NEVER a need to suppress stdout output inside a conditional (whether [ ... ] or [[ ... ]], as no stdout output is passed through; thus, the > /dev/null is redundant (that said, with a command substitution inside a conditional, stderr output IS passed through).

Why do I get a SyntaxError for a Unicode escape in my file path?

I had the same error. Basically, I suspect that the path cannot start either with "U" or "User" after "C:\". I changed my directory to "c:\file_name.png" by putting the file that I want to access from python right under the 'c:\' path.

In your case, if you have to access the "python" folder, perhaps reinstall the python, and change the installation path to something like "c:\python". Otherwise, just avoid the "...\User..." in your path, and put your project under C:.

Set value for particular cell in pandas DataFrame using index

From version 0.21.1 you can also use .at method. There are some differences compared to .loc as mentioned here - pandas .at versus .loc, but it's faster on single value replacement

How to hide a div with jQuery?

$("myDiv").hide(); and $("myDiv").show(); does not work in Internet Explorer that well.

The way I got around this was to get the html content of myDiv using .html().

I then wrote it to a newly created DIV. I then appended the DIV to the body and appended the content of the variable Content to the HiddenField then read that contents from the newly created div when I wanted to show the DIV.

After I used the .remove() method to get rid of the DIV that was temporarily holding my DIVs html.

var Content = $('myDiv').html(); 
        $('myDiv').empty();
        var hiddenField = $("<input type='hidden' id='myDiv2'>");
        $('body').append(hiddenField);
        HiddenField.val(Content);

and then when I wanted to SHOW the content again.

        var Content = $('myDiv');
        Content.html($('#myDiv2').val());
        $('#myDiv2').remove();

This was more reliable that the .hide() & .show() methods.

PhpMyAdmin not working on localhost

Found a fix. (If you are using proxy on your network) //Windows 1. Open control panel 2. Network and internet 3. Network and sharing center 4. On the bottom left side of the window, you will see Internet Options, under connections tab, click LAN settings check the bypass

Read file line by line in PowerShell

The almighty switch works well here:

'one
two
three' > file

$regex = '^t'

switch -regex -file file { 
  $regex { "line is $_" } 
}

Output:

line is two
line is three

How to get access to HTTP header information in Spring MVC REST controller?

My solution in Header parameters with example is user="test" is:

@RequestMapping(value = "/restURL")
  public String serveRest(@RequestBody String body, @RequestHeader HttpHeaders headers){

System.out.println(headers.get("user"));
}

TSQL Pivot without aggregate function

The OP didn't actually need to pivot without agregation but for those of you coming here to know how see:

sql parameterised cte query

The answer to that question involves a situation where pivot without aggregation is needed so an example of doing it is part of the solution.

How can I send an email through the UNIX mailx command?

mailx -s "subjec_of_mail" [email protected] < file_name

through mailx utility we can send a file from unix to mail server. here in above code we can see first parameter is -s "subject of mail" the second parameter is mail ID and the last parameter is name of file which we want to attach

Flask Error: "Method Not Allowed The method is not allowed for the requested URL"

What is happening here is that database route does not accept any url methods.

I would try putting the url methods in the app route just like you have in the entry_page function:

@app.route('/entry', methods=['GET', 'POST'])
def entry_page():
    if request.method == 'POST':
        date = request.form['date']
        title = request.form['blog_title']
        post = request.form['blog_main']
        post_entry = models.BlogPost(date = date, title = title, post = post)
        db.session.add(post_entry)
        db.session.commit()
        return redirect(url_for('database'))
    else:
        return render_template('entry.html')

@app.route('/database', methods=['GET', 'POST'])        
def database():
    query = []
    for i in session.query(models.BlogPost):
        query.append((i.title, i.post, i.date))
    return render_template('database.html', query = query)

How to deal with certificates using Selenium?

I had the exact same issue. However when I tried opening the website manually in the browser the certificate was correct, but in the details the name was "DONOTTRUST".

The difference of certificate was caused by Fiddler that was running in background and decrypting all HTTPS content before reencrypting it.

To fix my problem, just close Fiddler on machine. If you need to keep Fiddler opened, then you can uncheck Decrypt SSL in Fiddler Settings.

What's the difference between tilde(~) and caret(^) in package.json?

One liner explanation

The standard versioning system is major.minor.build (e.g. 2.4.1)

npm checks and fixes the version of a particular package based on these characters

~ : major version is fixed, minor version is fixed, matches any build number

e.g. : ~2.4.1 means it will check for 2.4.x where x is anything

^ : major version is fixed, matches any minor version, matches any build number

e.g. : ^2.4.1 means it will check for 2.x.x where x is anything

Remove excess whitespace from within a string

$str = trim(preg_replace('/\s+/',' ', $str));

The above line of code will remove extra spaces, as well as leading and trailing spaces.

How do I set environment variables from Java?

Tried pushy's answer above and it worked for the most part. However, in certain circumstances, I would see this exception:

java.lang.String cannot be cast to java.lang.ProcessEnvironment$Variable

This turns out to happen when the method was called more than once, owing to the implementation of certain inner classes of ProcessEnvironment. If the setEnv(..) method is called more than once, when the keys are retrieved from the theEnvironment map, they are now strings (having been put in as strings by the first invocation of setEnv(...) ) and cannot be cast to the map's generic type, Variable, which is a private inner class of ProcessEnvironment.

A fixed version (in Scala), is below. Hopefully it isn't too difficult to carry over into Java.

def setEnv(newenv: java.util.Map[String, String]): Unit = {
  try {
    val processEnvironmentClass = JavaClass.forName("java.lang.ProcessEnvironment")
    val theEnvironmentField = processEnvironmentClass.getDeclaredField("theEnvironment")
    theEnvironmentField.setAccessible(true)

    val variableClass = JavaClass.forName("java.lang.ProcessEnvironment$Variable")
    val convertToVariable = variableClass.getMethod("valueOf", classOf[java.lang.String])
    convertToVariable.setAccessible(true)

    val valueClass = JavaClass.forName("java.lang.ProcessEnvironment$Value")
    val convertToValue = valueClass.getMethod("valueOf", classOf[java.lang.String])
    convertToValue.setAccessible(true)

    val sampleVariable = convertToVariable.invoke(null, "")
    val sampleValue = convertToValue.invoke(null, "")
    val env = theEnvironmentField.get(null).asInstanceOf[java.util.Map[sampleVariable.type, sampleValue.type]]
    newenv.foreach { case (k, v) => {
        val variable = convertToVariable.invoke(null, k).asInstanceOf[sampleVariable.type]
        val value = convertToValue.invoke(null, v).asInstanceOf[sampleValue.type]
        env.put(variable, value)
      }
    }

    val theCaseInsensitiveEnvironmentField = processEnvironmentClass.getDeclaredField("theCaseInsensitiveEnvironment")
    theCaseInsensitiveEnvironmentField.setAccessible(true)
    val cienv = theCaseInsensitiveEnvironmentField.get(null).asInstanceOf[java.util.Map[String, String]]
    cienv.putAll(newenv);
  }
  catch {
    case e : NoSuchFieldException => {
      try {
        val classes = classOf[java.util.Collections].getDeclaredClasses
        val env = System.getenv()
        classes foreach (cl => {
          if("java.util.Collections$UnmodifiableMap" == cl.getName) {
            val field = cl.getDeclaredField("m")
            field.setAccessible(true)
            val map = field.get(env).asInstanceOf[java.util.Map[String, String]]
            // map.clear() // Not sure why this was in the code. It means we need to set all required environment variables.
            map.putAll(newenv)
          }
        })
      } catch {
        case e2: Exception => e2.printStackTrace()
      }
    }
    case e1: Exception => e1.printStackTrace()
  }
}

How do I empty an array in JavaScript?

If you need to keep the original array because you have other references to it that should be updated too, you can clear it without creating a new array by setting its length to zero:

A.length = 0;

How to run TypeScript files from command line?

For environments such as Webstorm where the node command cannot be changed to ts-node or npx:

  1. npm install ts-node typescript (Install dependencies)
  2. node --require ts-node/register src/foo.ts (Add --require ts-node/register to "Node parameters")

How to properly add cross-site request forgery (CSRF) token using PHP

CSRF protection

TYPES OF CSRF USAGE

IN FORM

<form>
   @csrf
</form>

or

<input type="hidden" name="token" value="{{ form_token() }}" />

META TAG

<meta name="csrf-token" content="{{ csrf_token() }}">

AJAX

$.ajaxSetup({
    headers: {
        'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
    }
});

SESSION

use Illuminate\Http\Request;

Route::get('/token', function (Request $request) {
    $token = $request->session()->token();

    $token = csrf_token();

    // ...
});

MIDDLEWARE

 App\Providers\RouteServiceProvider

<?php

namespace App\Http\Middleware;

use Illuminate\Foundation\Http\Middleware\VerifyCsrfToken as Middleware;

class VerifyCsrfToken extends Middleware
{
    /**
     * The URIs that should be excluded from CSRF verification.
     *
     * @var array
     */
    protected $except = [
        'stripe/*',
        'http://example.com/foo/bar',
        'http://example.com/foo/*',
    ];
}

In C#, should I use string.Empty or String.Empty or "" to intitialize a string?

string is synonym for System.String type, They are identical.

Values are also identical: string.Empty == String.Empty == ""

I would not use character constant "" in code, rather string.Empty or String.Empty - easier to see what programmer meant.

Between string and String I like lower case string more just because I used to work with Delphi for lot of years and Delphi style is lowercase string.

So, if I was your boss, you would be writing string.Empty

CSV in Python adding an extra carriage return, on Windows

You can introduce the lineterminator='\n' parameter in the csv writer command.

import csv
delimiter='\t'
with open('tmp.csv', '+w', encoding='utf-8') as stream:
    writer = csv.writer(stream, delimiter=delimiter, quoting=csv.QUOTE_NONE, quotechar='',  lineterminator='\n')
    writer.writerow(['A1' , 'B1', 'C1'])
    writer.writerow(['A2' , 'B2', 'C2'])
    writer.writerow(['A3' , 'B3', 'C3'])

Convert time in HH:MM:SS format to seconds only?

<?php
$time    = '21:32:32';
$seconds = 0;
$parts   = explode(':', $time);

if (count($parts) > 2) {
    $seconds += $parts[0] * 3600;
}
$seconds += $parts[1] * 60;
$seconds += $parts[2];

How can one see the structure of a table in SQLite?

You will get the structure by typing the command:

.schema <tableName>

regular expression for anything but an empty string

Create "regular expression to detect empty string", and then inverse it. Invesion of regular language is the regular language. I think regular expression library in what you leverage - should support it, but if not you always can write your own library.

grep --invert-match

C++: Where to initialize variables in constructor

Option 1 allows you to use a place specified exactly for explicitly initializing member variables.

Script @php artisan package:discover handling the post-autoload-dump event returned with error code 1

In case the error appears when upgrading from Laravel 6 to Laravel 7, the command composer require laravel/ui "^2.0" solves the problem (see https://laravel.com/docs/7.x/upgrade#authentication -scaffolding)

NewtonSoft.Json Serialize and Deserialize class with property of type IEnumerable<ISomeInterface>

You don't need to use JsonConverterAttribute, keep your model clean, also use CustomCreationConverter, the code is simpler:

public class SampleConverter : CustomCreationConverter<ISample>
{
    public override ISample Create(Type objectType)
    {
        return new Sample();
    }
}

Then:

var sz = JsonConvert.SerializeObject( sampleGroupInstance );
JsonConvert.DeserializeObject<SampleGroup>( sz, new SampleConverter());

Documentation: Deserialize with CustomCreationConverter

How to turn a String into a JavaScript function call?

If settings.functionName is already a function, you could do this:

settings.functionName(t.parentNode.id);

Otherwise this should also work if settings.functionName is just the name of the function:

if (typeof window[settings.functionName] == "function") {
    window[settings.functionName](t.parentNode.id);
}