Programs & Examples On #Non convex

Write a formula in an Excel Cell using VBA

I don't know why, but if you use

(...)Formula = "=SUM(D2,E2)"

(',' instead of ';'), it works.

If you step through your sub in the VB script editor (F8), you can add Range("F2").Formula to the watch window and see what the formular looks like from a VB point of view. It seems that the formular shown in Excel itself is sometimes different from the formular that VB sees...

Datatables: Cannot read property 'mData' of undefined

I had a dynamically generated, but badly formed table with a typo. I copied a <td> tag inside another <td> by mistake. My column count matched. I had <thead> and <tbody> tags. Everything matched, except for this little mistake I didn't notice for a while, because my column had a lot of link and image tags in it.

Git pull a certain branch from GitHub

you may also do

git pull -r origin master

fix merge conflicts if any

git rebase --continue

-r is for rebase. This will make you branch structure from

        v  master       
o-o-o-o-o
     \o-o-o
          ^ other branch

to

        v  master       
o-o-o-o-o-o-o-o
              ^ other branch

This will lead to a cleaner history. Note: In case you have already pushed your other-branch to origin( or any other remote), you may have to force push your branch after rebase.

git push -f origin other-branch

Configure Apache .conf for Alias

Sorry not sure what was going on this worked in the end:

<VirtualHost *> 
    ServerName example.com
    DocumentRoot /var/www/html/mjp

    Alias /ncn "/var/www/html/ncn"

    <Directory "/var/www/html/ncn">
        Options None
        AllowOverride None
        Order allow,deny
        Allow from all
    </Directory>
</VirtualHost>

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

Tilde (~)

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

"express": "~4.13.3" 

~4.13.3 means it will check for 4.13.x where x is anything and 4.14.0

Caret (^)

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

"supertest": "^3.0.0"

^3.0.0 means it will check for 3.x.x where x is anything

Replace characters from a column of a data frame R

chartr is also convenient for these types of substitutions:

chartr("_", "-", data1$c)
#  [1] "A-B" "A-B" "A-B" "A-B" "A-C" "A-C" "A-C" "A-C" "A-C" "A-C"

Thus, you can just do:

data1$c <- chartr("_", "-", data1$c)

SQL Server : GROUP BY clause to get comma-separated values

SELECT  [ReportId], 
        SUBSTRING(d.EmailList,1, LEN(d.EmailList) - 1) EmailList
FROM
        (
            SELECT DISTINCT [ReportId]
            FROM Table1
        ) a
        CROSS APPLY
        (
            SELECT [Email] + ', ' 
            FROM Table1 AS B 
            WHERE A.[ReportId] = B.[ReportId]
            FOR XML PATH('')
        ) D (EmailList) 

SQLFiddle Demo

Read text from response

Your "application/xrds+xml" was giving me issues, I was receiving a Content-Length of 0 (no response).

After removing that, you can access the response using response.GetResponseStream().

HttpWebRequest request = WebRequest.Create("http://google.com") as HttpWebRequest;

//request.Accept = "application/xrds+xml";  
HttpWebResponse response = (HttpWebResponse)request.GetResponse();

WebHeaderCollection header = response.Headers;

var encoding = ASCIIEncoding.ASCII;
using (var reader = new System.IO.StreamReader(response.GetResponseStream(), encoding))
{
    string responseText = reader.ReadToEnd();
}

IIS: Display all sites and bindings in PowerShell

The most easy way as I saw:

Foreach ($Site in get-website) { Foreach ($Bind in $Site.bindings.collection) {[pscustomobject]@{name=$Site.name;Protocol=$Bind.Protocol;Bindings=$Bind.BindingInformation}}}

How to debug a bash script?

I've used the following methods to debug my script.

set -e makes the script stop immediately if any external program returns a non-zero exit status. This is useful if your script attempts to handle all error cases and where a failure to do so should be trapped.

set -x was mentioned above and is certainly the most useful of all the debugging methods.

set -n might also be useful if you want to check your script for syntax errors.

strace is also useful to see what's going on. Especially useful if you haven't written the script yourself.

Simple InputBox function

It would be something like this

function CustomInputBox([string] $title, [string] $message, [string] $defaultText) 
{
$inputObject = new-object -comobject MSScriptControl.ScriptControl
$inputObject.language = "vbscript" 
$inputObject.addcode("function getInput() getInput = inputbox(`"$message`",`"$title`" , `"$defaultText`") end function" ) 
$_userInput = $inputObject.eval("getInput") 

return $_userInput
}

Then you can call the function similar to this.

$userInput = CustomInputBox "User Name" "Please enter your name." ""
if ( $userInput -ne $null ) 
{
 echo "Input was [$userInput]"
}
else
{
 echo "User cancelled the form!"
}

This is the most simple way to do this that I can think of.

Show hidden div on ng-click within ng-repeat

Remove the display:none, and use ng-show instead:

<ul class="procedures">
    <li ng-repeat="procedure in procedures | filter:query | orderBy:orderProp">
        <h4><a href="#" ng-click="showDetails = ! showDetails">{{procedure.definition}}</a></h4>
         <div class="procedure-details" ng-show="showDetails">
            <p>Number of patient discharges: {{procedure.discharges}}</p>
            <p>Average amount covered by Medicare: {{procedure.covered}}</p>
            <p>Average total payments: {{procedure.payments}}</p>
         </div>
    </li>
</ul>

Here's the fiddle: http://jsfiddle.net/asmKj/


You can also use ng-class to toggle a class:

<div class="procedure-details" ng-class="{ 'hidden': ! showDetails }">

I like this more, since it allows you to do some nice transitions: http://jsfiddle.net/asmKj/1/

Interfaces with static fields in java for sharing 'constants'

Instead of implementing a "constants interface", in Java 1.5+, you can use static imports to import the constants/static methods from another class/interface:

import static com.kittens.kittenpolisher.KittenConstants.*;

This avoids the ugliness of making your classes implement interfaces that have no functionality.

As for the practice of having a class just to store constants, I think it's sometimes necessary. There are certain constants that just don't have a natural place in a class, so it's better to have them in a "neutral" place.

But instead of using an interface, use a final class with a private constructor. (Making it impossible to instantiate or subclass the class, sending a strong message that it doesn't contain non-static functionality/data.)

Eg:

/** Set of constants needed for Kitten Polisher. */
public final class KittenConstants
{
    private KittenConstants() {}

    public static final String KITTEN_SOUND = "meow";
    public static final double KITTEN_CUTENESS_FACTOR = 1;
}

Extract month and year from a zoo::yearmon object

I know the OP is using zoo here, but I found this thread googling for a standard ts solution for the same problem. So I thought I'd add a zoo-free answer for ts as well.

# create an example Date 
date_1 <- as.Date("1990-01-01")
# extract year
as.numeric(format(date_1, "%Y"))
# extract month
as.numeric(format(date_1, "%m"))

How do I make JavaScript beep?

<html>
<head>
    <script src='https://surikov.github.io/webaudiofont/npm/dist/WebAudioFontPlayer.js'></script>
    <script src='https://surikov.github.io/webaudiofontdata/sound/0000_JCLive_sf2_file.js'></script>
    <script>
        var selectedPreset=_tone_0000_JCLive_sf2_file;
        var AudioContextFunc = window.AudioContext || window.webkitAudioContext;
        var audioContext = new AudioContextFunc();
        var player=new WebAudioFontPlayer();
        player.loader.decodeAfterLoading(audioContext, '_tone_0000_JCLive_sf2_file');
    </script>
</head>
<body>
    <p><a href="#" onmousedown="player.queueWaveTable(audioContext, audioContext.destination, selectedPreset, 0, 55, 3.5);">Play a note</a></p>
    <hr/>
    <p><a href="https://github.com/surikov/webaudiofont">source</a></p>
</body>

listen here https://jsbin.com/lamidog/1/edit?html,output

Python module os.chmod(file, 664) does not change the permission to rw-rw-r-- but -w--wx----

Using the stat.* bit masks does seem to me the most portable and explicit way of doing this. But on the other hand, I often forget how best to handle that. So, here's an example of masking out the 'group' and 'other' permissions and leaving 'owner' permissions untouched. Using bitmasks and subtraction is a useful pattern.

import os
import stat
def chmodme(pn):
    """Removes 'group' and 'other' perms. Doesn't touch 'owner' perms."""
    mode = os.stat(pn).st_mode
    mode -= (mode & (stat.S_IRWXG | stat.S_IRWXO))
    os.chmod(pn, mode)

jQuery get mouse position within an element

One way is to use the jQuery offset method to translate the event.pageX and event.pageY coordinates from the event into a mouse position relative to the parent. Here's an example for future reference:

$("#something").click(function(e){
   var parentOffset = $(this).parent().offset(); 
   //or $(this).offset(); if you really just want the current element's offset
   var relX = e.pageX - parentOffset.left;
   var relY = e.pageY - parentOffset.top;
});

Password must have at least one non-alpha character

  function randomPassword(length) {
        var chars = "abcdefghijklmnopqrstuvwxyz#$%ABCDEFGHIJKLMNOP1234567890";
        var pass = "";
        for (var x = 0; x < length; x++) {
            var i = Math.floor(Math.random() * chars.length);
            pass += chars.charAt(i);
        }
        var pattern = false;
        var passwordpattern = new RegExp("[^a-zA-Z0-9+]+[0-9+]+[A-Z+]+[a-z+]");
        pattern = passwordpattern.test(pass);
        if (pattern == true)
            { alert(pass); }
        else
         { randomPassword(length); }
    }

try this to create the random password with atleast one special character

SQL Format as of Round off removing decimals

SELECT CONVERT(INT, 11.4)

RESULT: 11

SELECT CONVERT(INT, 11.6)

RESULT: 11

Adding a directory to the PATH environment variable in Windows

On Windows 10, I was able to search for set path environment variable and got these instructions:

  1. From the desktop, right-click the very bottom-left corner of the screen to get the Power User Task Menu.
  2. From the Power User Task Menu, click System.
  3. In the Settings window, scroll down to the Related settings section and click the System info link.
  4. In the System window, click the Advanced system settings link in the left navigation panel.
  5. In the System Properties window, click the Advanced tab, then click the Environment Variables button near the bottom of that tab.
  6. In the Environment Variables window (pictured below), highlight the Path variable in the System variables section and click the Edit button. Add or modify the path lines with the paths you want the computer to access. Each different directory is separated with a semicolon, as shown below:

C:\Program Files;C:\Winnt;C:\Winnt\System32

The first time I searched for it, it immediately popped up the System Properties Window. After that, I found the above instructions.

INSERT INTO TABLE from comma separated varchar-list

Sql Server does not (on my knowledge) have in-build Split function. Split function in general on all platforms would have comma-separated string value to be split into individual strings. In sql server, the main objective or necessary of the Split function is to convert a comma-separated string value (‘abc,cde,fgh’) into a temp table with each string as rows.

The below Split function is Table-valued function which would help us splitting comma-separated (or any other delimiter value) string to individual string.

CREATE FUNCTION dbo.Split(@String varchar(8000), @Delimiter char(1))       
returns @temptable TABLE (items varchar(8000))       
as       
begin       
    declare @idx int       
    declare @slice varchar(8000)       

    select @idx = 1       
        if len(@String)<1 or @String is null  return       

    while @idx!= 0       
    begin       
        set @idx = charindex(@Delimiter,@String)       
        if @idx!=0       
            set @slice = left(@String,@idx - 1)       
        else       
            set @slice = @String       

        if(len(@slice)>0)  
            insert into @temptable(Items) values(@slice)       

        set @String = right(@String,len(@String) - @idx)       
        if len(@String) = 0 break       
    end   
return       
end  

select top 10 * from dbo.split('Chennai,Bangalore,Mumbai',',')

the complete can be found at follownig link http://www.logiclabz.com/sql-server/split-function-in-sql-server-to-break-comma-separated-strings-into-table.aspx

Select mysql query between date?

select * from *table_name* where *datetime_column* between '01/01/2009' and curdate()

or using >= and <= :

select * from *table_name* where *datetime_column* >= '01/01/2009' and *datetime_column* <= curdate()

No provider for Http StaticInjectorError

I was trying to fix the issue for about an hour and just deiced to restart the server. Only to see the issue is fixed.

If you make changes to APP module and the issue remains the same, stop the server and try running the serve command again.

Using ionic 4 with angular 7

How do I hide the bullets on my list for the sidebar?

You have a selector ul on line 252 which is setting list-style: square outside none (a square bullet). You'll have to change it to list-style: none or just remove the line.

If you only want to remove the bullets from that specific instance, you can use the specific selector for that list and its items as follows:

ul#groups-list.items-list { list-style: none }

Java Date - Insert into database

Granted, PreparedStatement will make your code better, but to answer your question you need to tell the DBMS the format of your string representation of the Date. In Oracle (you don't name your database vendor) a string date is converted to Date using the TO_DATE() function:

INSERT INTO TABLE_NAME(
  date_column
)values(
  TO_DATE('06/06/2006', 'mm/dd/yyyy')
)

Nested attributes unpermitted parameters

or you can simply use

def question_params

  params.require(:question).permit(team_ids: [])

end

How can I control Chromedriver open window size?

RUBY


Approach #1

options = {
      'chromeOptions' => {
          'args' => ['start-fullscreen']
      }
  }

caps = Selenium::WebDriver::Remote::Capabilities.chrome(options)
@driver = Selenium::WebDriver.for :chrome, desired_capabilities: caps

Approach #2

options = {
      'chromeOptions' => {
          'args' => ['window-size=640,480']
      }
  }

caps = Selenium::WebDriver::Remote::Capabilities.chrome(options)
@driver = Selenium::WebDriver.for :chrome, desired_capabilities: caps

Approach #3

max_width, max_height = @driver.execute_script("return [window.screen.availWidth, window.screen.availHeight];")
@driver.manage.window.resize_to(max_width, max_height)

Approach #4

@driver.manage.window.maximize

Approach #5

target_size = Selenium::WebDriver::Dimension.new(1600, 1268)
@driver.manage.window.size = target_size

Approach #6

@driver.manage.window.resize_to(640, 480)

Approach #7

@driver.execute_script("window.resizeTo(640, 480);")

Python creating a dictionary of lists

Your question has already been answered, but IIRC you can replace lines like:

if d.has_key(scope_item):

with:

if scope_item in d:

That is, d references d.keys() in that construction. Sometimes defaultdict isn't the best option (for example, if you want to execute multiple lines of code after the else associated with the above if), and I find the in syntax easier to read.

Get values from a listbox on a sheet

To get the value of the selected item of a listbox then use the following.

For Single Column ListBox: ListBox1.List(ListBox1.ListIndex)

For Multi Column ListBox: ListBox1.Column(column_number, ListBox1.ListIndex)

This avoids looping and is extremely more efficient.

"Fatal error: Cannot redeclare <function>"

I had strange behavor when my *.php.bak (which automaticly was created by notepad) was included in compilation. After I removed all *.php.bak from folder this error was gone. Maybe this will be helpful for someone.

Can I set state inside a useEffect hook

? 1. Can I set state inside a useEffect hook?

In principle, you can set state freely where you need it - including inside useEffect and even during rendering. Just make sure to avoid infinite loops by settting Hook deps properly and/or state conditionally.


? 2. Lets say I have some state that is dependent on some other state. Is it appropriate to create a hook that observes A and sets B inside the useEffect hook?

You just described the classic use case for useReducer:

useReducer is usually preferable to useState when you have complex state logic that involves multiple sub-values or when the next state depends on the previous one. (React docs)

When setting a state variable depends on the current value of another state variable, you might want to try replacing them both with useReducer. [...] When you find yourself writing setSomething(something => ...), it’s a good time to consider using a reducer instead. (Dan Abramov, Overreacted blog)

_x000D_
_x000D_
let MyComponent = () => {_x000D_
  let [state, dispatch] = useReducer(reducer, { a: 1, b: 2 });_x000D_
_x000D_
  useEffect(() => {_x000D_
    console.log("Some effect with B");_x000D_
  }, [state.b]);_x000D_
_x000D_
  return (_x000D_
    <div>_x000D_
      <p>A: {state.a}, B: {state.b}</p>_x000D_
      <button onClick={() => dispatch({ type: "SET_A", payload: 5 })}>_x000D_
        Set A to 5 and Check B_x000D_
      </button>_x000D_
      <button onClick={() => dispatch({ type: "INCREMENT_B" })}>_x000D_
        Increment B_x000D_
      </button>_x000D_
    </div>_x000D_
  );_x000D_
};_x000D_
_x000D_
// B depends on A. If B >= A, then reset B to 1._x000D_
function reducer(state, { type, payload }) {_x000D_
  const someCondition = state.b >= state.a;_x000D_
_x000D_
  if (type === "SET_A")_x000D_
    return someCondition ? { a: payload, b: 1 } : { ...state, a: payload };_x000D_
  else if (type === "INCREMENT_B") return { ...state, b: state.b + 1 };_x000D_
  return state;_x000D_
}_x000D_
_x000D_
ReactDOM.render(<MyComponent />, document.getElementById("root"));
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.13.0/umd/react.production.min.js" integrity="sha256-32Gmw5rBDXyMjg/73FgpukoTZdMrxuYW7tj8adbN8z4=" crossorigin="anonymous"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.13.0/umd/react-dom.production.min.js" integrity="sha256-bjQ42ac3EN0GqK40pC9gGi/YixvKyZ24qMP/9HiGW7w=" crossorigin="anonymous"></script>_x000D_
<div id="root"></div>_x000D_
<script>var { useReducer, useEffect } = React</script>
_x000D_
_x000D_
_x000D_


? 3. Will the effects cascade such that, when I click the button, the first effect will fire, causing b to change, causing the second effect to fire, before the next render?

useEffect always runs after the render is committed and DOM changes are applied. The first effect fires, changes b and causes a re-render. After this render has completed, second effect will run due to b changes.

_x000D_
_x000D_
let MyComponent = props => {_x000D_
  console.log("render");_x000D_
  let [a, setA] = useState(1);_x000D_
  let [b, setB] = useState(2);_x000D_
_x000D_
  let isFirstRender = useRef(true);_x000D_
_x000D_
  useEffect(() => {_x000D_
    console.log("useEffect a, value:", a);_x000D_
    if (isFirstRender.current) isFirstRender.current = false;_x000D_
    else setB(3);_x000D_
    return () => {_x000D_
      console.log("unmount useEffect a, value:", a);_x000D_
    };_x000D_
  }, [a]);_x000D_
  useEffect(() => {_x000D_
    console.log("useEffect b, value:", b);_x000D_
    return () => {_x000D_
      console.log("unmount useEffect b, value:", b);_x000D_
    };_x000D_
  }, [b]);_x000D_
_x000D_
  return (_x000D_
    <div>_x000D_
      <p>a: {a}, b: {b}</p>_x000D_
      <button_x000D_
        onClick={() => {_x000D_
          console.log("Clicked!");_x000D_
          setA(5);_x000D_
        }}_x000D_
      >_x000D_
        click me_x000D_
      </button>_x000D_
    </div>_x000D_
  );_x000D_
};_x000D_
_x000D_
ReactDOM.render(<MyComponent />, document.getElementById("root"));
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.13.0/umd/react.production.min.js" integrity="sha256-32Gmw5rBDXyMjg/73FgpukoTZdMrxuYW7tj8adbN8z4=" crossorigin="anonymous"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.13.0/umd/react-dom.production.min.js" integrity="sha256-bjQ42ac3EN0GqK40pC9gGi/YixvKyZ24qMP/9HiGW7w=" crossorigin="anonymous"></script>_x000D_
<div id="root"></div>_x000D_
<script>var { useReducer, useEffect, useState, useRef } = React</script>
_x000D_
_x000D_
_x000D_


? 4. Are there any performance downsides to structuring code like this?

Yes. By wrapping the state change of b in a separate useEffect for a, the browser has an additional layout/paint phase - these effects are potentially visible for the user. If there is no way you want give useReducer a try, you could change b state together with a directly:

_x000D_
_x000D_
let MyComponent = () => {_x000D_
  console.log("render");_x000D_
  let [a, setA] = useState(1);_x000D_
  let [b, setB] = useState(2);_x000D_
_x000D_
  useEffect(() => {_x000D_
    console.log("useEffect b, value:", b);_x000D_
    return () => {_x000D_
      console.log("unmount useEffect b, value:", b);_x000D_
    };_x000D_
  }, [b]);_x000D_
_x000D_
  const handleClick = () => {_x000D_
    console.log("Clicked!");_x000D_
    setA(5);_x000D_
    b >= 5 ? setB(1) : setB(b + 1);_x000D_
  };_x000D_
_x000D_
  return (_x000D_
    <div>_x000D_
      <p>_x000D_
        a: {a}, b: {b}_x000D_
      </p>_x000D_
      <button onClick={handleClick}>click me</button>_x000D_
    </div>_x000D_
  );_x000D_
};_x000D_
_x000D_
ReactDOM.render(<MyComponent />, document.getElementById("root"));
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.13.0/umd/react.production.min.js" integrity="sha256-32Gmw5rBDXyMjg/73FgpukoTZdMrxuYW7tj8adbN8z4=" crossorigin="anonymous"></script>_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.13.0/umd/react-dom.production.min.js" integrity="sha256-bjQ42ac3EN0GqK40pC9gGi/YixvKyZ24qMP/9HiGW7w=" crossorigin="anonymous"></script>_x000D_
<div id="root"></div>_x000D_
<script>var { useReducer, useEffect, useState, useRef } = React</script>
_x000D_
_x000D_
_x000D_

Resolve absolute path from relative path and/or file name

I came across a similar need this morning: how to convert a relative path into an absolute path inside a Windows command script.

The following did the trick:

@echo off

set REL_PATH=..\..\
set ABS_PATH=

rem // Save current directory and change to target directory
pushd %REL_PATH%

rem // Save value of CD variable (current directory)
set ABS_PATH=%CD%

rem // Restore original directory
popd

echo Relative path: %REL_PATH%
echo Maps to path: %ABS_PATH%

Attempt to set a non-property-list object as an NSUserDefaults

Swift 3 Solution

Simple utility class

class ArchiveUtil {

    private static let PeopleKey = "PeopleKey"

    private static func archivePeople(people : [Human]) -> NSData {

        return NSKeyedArchiver.archivedData(withRootObject: people as NSArray) as NSData
    }

    static func loadPeople() -> [Human]? {

        if let unarchivedObject = UserDefaults.standard.object(forKey: PeopleKey) as? Data {

            return NSKeyedUnarchiver.unarchiveObject(with: unarchivedObject as Data) as? [Human]
        }

        return nil
    }

    static func savePeople(people : [Human]?) {

        let archivedObject = archivePeople(people: people!)
        UserDefaults.standard.set(archivedObject, forKey: PeopleKey)
        UserDefaults.standard.synchronize()
    }

}

Model Class

class Human: NSObject, NSCoding {

    var name:String?
    var age:Int?

    required init(n:String, a:Int) {

        name = n
        age = a
    }


    required init(coder aDecoder: NSCoder) {

        name = aDecoder.decodeObject(forKey: "name") as? String
        age = aDecoder.decodeInteger(forKey: "age")
    }


    public func encode(with aCoder: NSCoder) {

        aCoder.encode(name, forKey: "name")
        aCoder.encode(age, forKey: "age")

    }
}

How to call

var people = [Human]()

people.append(Human(n: "Sazzad", a: 21))
people.append(Human(n: "Hissain", a: 22))
people.append(Human(n: "Khan", a: 23))

ArchiveUtil.savePeople(people: people)

let others = ArchiveUtil.loadPeople()

for human in others! {

    print("name = \(human.name!), age = \(human.age!)")
}

How to assert greater than using JUnit Assert?

you can also try below simple soln:

previousTokenValues[1] = "1378994409108";
currentTokenValues[1] = "1378994416509";

Long prev = Long.parseLong(previousTokenValues[1]);
Long curr = Long.parseLong(currentTokenValues[1]);

Assert.assertTrue(prev  > curr );   

how to open a jar file in Eclipse

Firstly, it's necessary to know what is a jar file.

From Oracle,

JAR (Java Archive) is a platform-independent file format that aggregates many files into one. Multiple Java applets and their requisite components (.class files, images and sounds) can be bundled in a JAR file and subsequently downloaded to a browser in a single HTTP transaction, greatly improving the download speed. The JAR format also supports compression, which reduces the file size, further improving the download time.

As you can see,

  1. It has nothing to do with a Eclipse project. An Eclipse project can be a Java project, C++ project and so on. It's just a self contain project that can be recognized and operated as an unit by Eclipse.
  2. The .class files are generally the main part of a jar file. It's impossible to view the source code(.java file) unless you decompile the executable file(.class file) by some tools. Take Eclipse for example, you can choose the plugin Eclipse Class Decompiler as the tool.

What is the difference between ( for... in ) and ( for... of ) statements?

A see a lot of good answers, but I decide to put my 5 cents just to have good example:

For in loop

iterates over all enumerable props

_x000D_
_x000D_
let nodes = document.documentElement.childNodes;_x000D_
_x000D_
for (var key in nodes) {_x000D_
  console.log( key );_x000D_
}
_x000D_
_x000D_
_x000D_

For of loop

iterates over all iterable values

_x000D_
_x000D_
let nodes = document.documentElement.childNodes;_x000D_
_x000D_
for (var node of nodes) {_x000D_
  console.log( node.toString() );_x000D_
}
_x000D_
_x000D_
_x000D_

AttributeError: 'module' object has no attribute

I faced the same issue. fixed by using reload.

import the_module_name
from importlib import reload
reload(the_module_name)

Forking / Multi-Threaded Processes | Bash

Let me try example

for x in 1 2 3 ; do { echo a $x ; sleep 1 ; echo b $x ; } &  done ; sleep 10

And use jobs to see what's running.

Useful example of a shutdown hook in Java?

You could do the following:

  • Let the shutdown hook set some AtomicBoolean (or volatile boolean) "keepRunning" to false
  • (Optionally, .interrupt the working threads if they wait for data in some blocking call)
  • Wait for the working threads (executing writeBatch in your case) to finish, by calling the Thread.join() method on the working threads.
  • Terminate the program

Some sketchy code:

  • Add a static volatile boolean keepRunning = true;
  • In run() you change to

    for (int i = 0; i < N && keepRunning; ++i)
        writeBatch(pw, i);
    
  • In main() you add:

    final Thread mainThread = Thread.currentThread();
    Runtime.getRuntime().addShutdownHook(new Thread() {
        public void run() {
            keepRunning = false;
            mainThread.join();
        }
    });
    

That's roughly how I do a graceful "reject all clients upon hitting Control-C" in terminal.


From the docs:

When the virtual machine begins its shutdown sequence it will start all registered shutdown hooks in some unspecified order and let them run concurrently. When all the hooks have finished it will then run all uninvoked finalizers if finalization-on-exit has been enabled. Finally, the virtual machine will halt.

That is, a shutdown hook keeps the JVM running until the hook has terminated (returned from the run()-method.

What tools do you use to test your public REST API?

We're planning to use FitNesse, with the RestFixture. We haven't started writing our tests yet, our newest tester got things up and running last week, however he has used FitNesse for this in his last company, so we know it's a reasonable setup for what we want to do.

More info available here: http://smartrics.blogspot.com/2008/08/get-fitnesse-with-some-rest.html

Changing the position of Bootstrap popovers based on the popover's X position in relation to window edge?

You can use auto in data placement like data-placement="auto left". It will automatic adjust according to your screen size and default placement will be left.

How do I return the SQL data types from my query?

There MUST be en easier way to do this... Low and behold, there is...!

"sp_describe_first_result_set" is your friend!

Now I do realise the question was asked specifically for SQL Server 2000, but I was looking for a similar solution for later versions and discovered some native support in SQL to achieve this.

In SQL Server 2012 onwards cf. "sp_describe_first_result_set" - Link to BOL

I had already implemented a solution using a technique similar to @Trisped's above and ripped it out to implement the native SQL Server implementation.

In case you're not on SQL Server 2012 or Azure SQL Database yet, here's the stored proc I created for pre-2012 era databases:

CREATE PROCEDURE [fn].[GetQueryResultMetadata] 
    @queryText VARCHAR(MAX)
AS
BEGIN

    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    --SET NOCOUNT ON;

    PRINT @queryText;

    DECLARE
                @sqlToExec NVARCHAR(MAX) = 
                    'SELECT TOP 1 * INTO #QueryMetadata FROM ('
                    +
                    @queryText
                    +
                    ') T;'
                    + '
                        SELECT
                                    C.Name                          [ColumnName],
                                    TP.Name                         [ColumnType],
                                    C.max_length                    [MaxLength],
                                    C.[precision]                   [Precision],
                                    C.[scale]                       [Scale],
                                    C.[is_nullable]                 IsNullable
                        FROM
                                    tempdb.sys.columns              C
                                        INNER JOIN
                                    tempdb.sys.types                TP
                                                                                ON
                                                                                        TP.system_type_id = C.system_type_id
                                                                                            AND
                                                                                        -- exclude custom types
                                                                                        TP.system_type_id = TP.user_type_id
                        WHERE
                                    [object_id] = OBJECT_ID(N''tempdb..#QueryMetadata'');
            '

    EXEC sp_executesql @sqlToExec

END

Create SQLite Database and table

The next link will bring you to a great tutorial, that helped me a lot!

How to SQLITE in C#

I nearly used everything in that article to create the SQLite database for my own C# Application.

Don't forget to download the SQLite.dll, and add it as a reference to your project. This can be done using NuGet and by adding the dll manually.

After you added the reference, refer to the dll from your code using the following line on top of your class:

using System.Data.SQLite;

You can find the dll's here:

SQLite DLL's

You can find the NuGet way here:

NuGet

Up next is the create script. Creating a database file:

SQLiteConnection.CreateFile("MyDatabase.sqlite");

SQLiteConnection m_dbConnection = new SQLiteConnection("Data Source=MyDatabase.sqlite;Version=3;");
m_dbConnection.Open();

string sql = "create table highscores (name varchar(20), score int)";

SQLiteCommand command = new SQLiteCommand(sql, m_dbConnection);
command.ExecuteNonQuery();

sql = "insert into highscores (name, score) values ('Me', 9001)";

command = new SQLiteCommand(sql, m_dbConnection);
command.ExecuteNonQuery();

m_dbConnection.Close();

After you created a create script in C#, I think you might want to add rollback transactions, it is safer and it will keep your database from failing, because the data will be committed at the end in one big piece as an atomic operation to the database and not in little pieces, where it could fail at 5th of 10 queries for example.

Example on how to use transactions:

 using (TransactionScope tran = new TransactionScope())
 {
     //Insert create script here.

     //Indicates that creating the SQLiteDatabase went succesfully, so the database can be committed.
     tran.Complete();
 }

iPhone/iOS JSON parsing tutorial

This is the tutorial I used to get to darrinm's answer. It's updated for ios5/6 and really easy. When I'm popular enough I'll delete this and add it as a comment to his answer.

http://www.raywenderlich.com/5492/working-with-json-in-ios-5

http://www.touch-code-magazine.com/tutorial-fetch-and-parse-json-in-ios6/

MySQL: Enable LOAD DATA LOCAL INFILE

The my.cnf file you should edit is the /etc/mysql/my.cnf file. Just:

sudo nano /etc/mysql/my.cnf

Then add:

[mysqld]
local-infile 

[mysql]
local-infile 

The headers [mysqld] and [mysql] are already given, just locate them in the file and add local-infile underneath each of them.

It works for me on MySQL 5.5 on Ubuntu 12.04 LTS.

Comparing strings in Java

You need both getText() - which returns an Editable and toString() - to convert that to a String for matching. So instead of: passw1.toString().equalsIgnoreCase("1234") you need passw1.getText().toString().equalsIgnoreCase("1234").

Split a string by a delimiter in python

You can use the str.split method: string.split('__')

>>> "MATCHES__STRING".split("__")
['MATCHES', 'STRING']

Func vs. Action vs. Predicate

The difference between Func and Action is simply whether you want the delegate to return a value (use Func) or not (use Action).

Func is probably most commonly used in LINQ - for example in projections:

 list.Select(x => x.SomeProperty)

or filtering:

 list.Where(x => x.SomeValue == someOtherValue)

or key selection:

 list.Join(otherList, x => x.FirstKey, y => y.SecondKey, ...)

Action is more commonly used for things like List<T>.ForEach: execute the given action for each item in the list. I use this less often than Func, although I do sometimes use the parameterless version for things like Control.BeginInvoke and Dispatcher.BeginInvoke.

Predicate is just a special cased Func<T, bool> really, introduced before all of the Func and most of the Action delegates came along. I suspect that if we'd already had Func and Action in their various guises, Predicate wouldn't have been introduced... although it does impart a certain meaning to the use of the delegate, whereas Func and Action are used for widely disparate purposes.

Predicate is mostly used in List<T> for methods like FindAll and RemoveAll.

hibernate could not get next sequence value

For anyone using FluentNHibernate (my version is 2.1.2), it's just as repetitive but this works:

public class UserMap : ClassMap<User>
{
    public UserMap()
    {
        Table("users");
        Id(x => x.Id).Column("id").GeneratedBy.SequenceIdentity("users_id_seq");

Error: Could not find or load main class

You have to set the classpath if you get the error:

Could not find or load main class XYZ

For example:

E:\>set path="c:\programfiles\Java\jdk1.7.0_17\bin"
E:\>set classpath=%classpath%;.;
E:\>javac XYZ.java
E:\>java XYZ

More than one file was found with OS independent path 'META-INF/LICENSE'

I faced this issue, first with some native libraries (.so files) and then with java/kotlin files. Turned out I was including a library from source as well as referencing artifactory through a transitive dependency. Check your dependency tree to see if there are any redundant entries. Use ./gradlew :app:dependencies to get the dependency tree. Replace "app" with your module name if the main module name is different.

TypeScript static classes

Abstract classes have been a first-class citizen of TypeScript since TypeScript 1.6. You cannot instantiate an abstract class.

Here is an example:

export abstract class MyClass {         
    public static myProp = "Hello";

    public static doSomething(): string {
      return "World";
    }
}

const okay = MyClass.doSomething();

//const errors = new MyClass(); // Error

Why Is `Export Default Const` invalid?

You can also do something like this if you want to export default a const/let, instead of

const MyComponent = ({ attr1, attr2 }) => (<p>Now Export On other Line</p>);
export default MyComponent

You can do something like this, which I do not like personally.

let MyComponent;
export default MyComponent = ({ }) => (<p>Now Export On SameLine</p>);

Google Maps API v3: How to remove all markers?

The solution is quite easy. You may use the method: marker.setMap(map);. Here, you define on which map the pin will appear.

So, if you set null in this method (marker.setMap(null);), the pin will disappear.


Now, you can write a function witch while make disappear all markers in your map.

You just add to put your pins in an array and declare them with markers.push (your_new pin) or this code for example:

// Adds a marker to the map and push to the array.
function addMarker(location) {
  var marker = new google.maps.Marker({
    position: location,
    map: map
  });
  markers.push(marker);
}

This is a function witch can set or disappear all the markers of your array in the map:

// Sets the map on all markers in the array.
  function setMapOnAll(map) {
    for (var i = 0; i < markers.length; i++) {
      markers[i].setMap(map);
    }
  }

To disappear all your markers, you should call the function with null:

// Removes the markers from the map, but keeps them in the array.
  function clearMarkers() {
    setMapOnAll(null);
  }

And, to remove and disappear, all your markers, you should reset your array of markers like this:

// Deletes all markers in the array by removing references to them.
  function deleteMarkers() {
    clearMarkers();
    markers = [];
  }

This is my complete code. It’s the simplest I could reduce to. Be care full you may replace YOUR_API_KEY in the code by your key google API:

<!DOCTYPE html>
<html>
  <head>
  <title>Remove Markers</title>
  <style>
     /* Always set the map height explicitly to define the size of the div
     * element that contains the map. */
     #map {
       height: 100%;
       }
  </style>
</head>
<body>

<div id="map"></div>
<p>Click on the map to add markers.</p>
<script>

  // In the following example, markers appear when the user clicks on the map.
  // The markers are stored in an array.
  // The user can then click an option to hide, show or delete the markers.
  var map;
  var markers = [];

  function initMap() {
    var haightAshbury = {lat: 37.769, lng: -122.446};

    map = new google.maps.Map(document.getElementById('map'), {
      zoom: 12,
      center: haightAshbury,
      mapTypeId: 'terrain'
    });

    // This event listener will call addMarker() when the map is clicked.
    map.addListener('click', function(event) {
      addMarker(event.latLng);
    });

    // Adds a marker at the center of the map.
    addMarker(haightAshbury);
  }

   // Adds a marker to the map and push to the array.
  function addMarker(location) {
    var marker = new google.maps.Marker({
      position: location,
      map: map
    });
    markers.push(marker);
  }

  // Sets the map on all markers in the array.
  function setMapOnAll(map) {
    for (var i = 0; i < markers.length; i++) {
      markers[i].setMap(map);
    }
  }

  // Removes the markers from the map, but keeps them in the array.
  function clearMarkers() {
    setMapOnAll(null);
  }

  // Shows any markers currently in the array.
  function showMarkers() {
    setMapOnAll(map);
  }

  // Deletes all markers in the array by removing references to them.
  function deleteMarkers() {
    clearMarkers();
    markers = [];
  }

</script>
   <script async defer
    src="https://maps.googleapis.com/maps/api/js key=YOUR_API_KEY&callback=initMap">
   </script>
</body>
</html>

You may consult google developer or the complete documentation on, also, google developer web site.

How to pass an array within a query string?

Although there isn't a standard on the URL part, there is one standard for JavaScript. If you pass objects containing arrays to URLSearchParams, and call toString() on it, it will transform it into a comma separated list of items:

let data = {
  str: 'abc',
  arr: ['abc', 123]
}

new URLSearchParams(data).toString();
// ?str=abc&arr=abc,123 (with escaped characters)

Retrieving Dictionary Value Best Practices

Well in fact TryGetValue is faster. How much faster? It depends on the dataset at hand. When you call the Contains method, Dictionary does an internal search to find its index. If it returns true, you need another index search to get the actual value. When you use TryGetValue, it searches only once for the index and if found, it assigns the value to your variable.

Edit:

Ok, I understand your confusion so let me elaborate:

Case 1:

if (myDict.Contains(someKey))
     someVal = myDict[someKey];

In this case there are 2 calls to FindEntry, one to check if the key exists and one to retrieve it

Case 2:

myDict.TryGetValue(somekey, out someVal)

In this case there is only one call to FindKey because the resulting index is kept for the actual retrieval in the same method.

C# SQL Server - Passing a list to a stored procedure

The only way I'm aware of is building CSV list and then passing it as string. Then, on SP side, just split it and do whatever you need.

Difference between SurfaceView and View?

One of the main differences between surfaceview and view is that to refresh the screen for a normal view we have to call invalidate method from the same thread where the view is defined. But even if we call invalidate, the refreshing does not happen immediately. It occurs only after the next arrival of the VSYNC signal. VSYNC signal is a kernel generated signal which happens every 16.6 ms or this is also known as 60 frame per second. So if we want more control over the refreshing of the screen (for example for very fast moving animation), we should not use normal view class.

On the other hand in case of surfaceview, we can refresh the screen as fast as we want and we can do it from a background thread. So refreshing of the surfaceview really does not depend upon VSYNC, and this is very useful if we want to do high speed animation. I have few training videos and example application which explain all these things nicely. Please have a look at the following training videos.

https://youtu.be/kRqsoApOr9U

https://youtu.be/Ji84HJ85FIQ

https://youtu.be/U8igPoyrUf8

Multiple FROMs - what it means

As of May 2017, multiple FROMs can be used in a single Dockerfile.
See "Builder pattern vs. Multi-stage builds in Docker" (by Alex Ellis) and PR 31257 by Tõnis Tiigi.

The general syntax involves adding FROM additional times within your Dockerfile - whichever is the last FROM statement is the final base image. To copy artifacts and outputs from intermediate images use COPY --from=<base_image_number>.

FROM golang:1.7.3 as builder
WORKDIR /go/src/github.com/alexellis/href-counter/
RUN go get -d -v golang.org/x/net/html  
COPY app.go    .
RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o app .

FROM alpine:latest  
RUN apk --no-cache add ca-certificates
WORKDIR /root/
COPY --from=builder /go/src/github.com/alexellis/href-counter/app    .
CMD ["./app"]  

The result would be two images, one for building, one with just the resulting app (much, much smaller)

REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE

multi               latest              bcbbf69a9b59        6 minutes ago       10.3MB  
golang              1.7.3               ef15416724f6        4 months ago        672MB  

what is a base image?

A set of files, plus EXPOSE'd ports, ENTRYPOINT and CMD.
You can add files and build a new image based on that base image, with a new Dockerfile starting with a FROM directive: the image mentioned after FROM is "the base image" for your new image.

does it mean that if I declare neo4j/neo4j in a FROM directive, that when my image is run the neo database will automatically run and be available within the container on port 7474?

Only if you don't overwrite CMD and ENTRYPOINT.
But the image in itself is enough: you would use a FROM neo4j/neo4j if you had to add files related to neo4j for your particular usage of neo4j.

How to upload, display and save images using node.js and express

First of all, you should make an HTML form containing a file input element. You also need to set the form's enctype attribute to multipart/form-data:

<form method="post" enctype="multipart/form-data" action="/upload">
    <input type="file" name="file">
    <input type="submit" value="Submit">
</form>

Assuming the form is defined in index.html stored in a directory named public relative to where your script is located, you can serve it this way:

const http = require("http");
const path = require("path");
const fs = require("fs");

const express = require("express");

const app = express();
const httpServer = http.createServer(app);

const PORT = process.env.PORT || 3000;

httpServer.listen(PORT, () => {
  console.log(`Server is listening on port ${PORT}`);
});

// put the HTML file containing your form in a directory named "public" (relative to where this script is located)
app.get("/", express.static(path.join(__dirname, "./public")));

Once that's done, users will be able to upload files to your server via that form. But to reassemble the uploaded file in your application, you'll need to parse the request body (as multipart form data).

In Express 3.x you could use express.bodyParser middleware to handle multipart forms but as of Express 4.x, there's no body parser bundled with the framework. Luckily, you can choose from one of the many available multipart/form-data parsers out there. Here, I'll be using multer:

You need to define a route to handle form posts:

const multer = require("multer");

const handleError = (err, res) => {
  res
    .status(500)
    .contentType("text/plain")
    .end("Oops! Something went wrong!");
};

const upload = multer({
  dest: "/path/to/temporary/directory/to/store/uploaded/files"
  // you might also want to set some limits: https://github.com/expressjs/multer#limits
});


app.post(
  "/upload",
  upload.single("file" /* name attribute of <file> element in your form */),
  (req, res) => {
    const tempPath = req.file.path;
    const targetPath = path.join(__dirname, "./uploads/image.png");

    if (path.extname(req.file.originalname).toLowerCase() === ".png") {
      fs.rename(tempPath, targetPath, err => {
        if (err) return handleError(err, res);

        res
          .status(200)
          .contentType("text/plain")
          .end("File uploaded!");
      });
    } else {
      fs.unlink(tempPath, err => {
        if (err) return handleError(err, res);

        res
          .status(403)
          .contentType("text/plain")
          .end("Only .png files are allowed!");
      });
    }
  }
);

In the example above, .png files posted to /upload will be saved to uploaded directory relative to where the script is located.

In order to show the uploaded image, assuming you already have an HTML page containing an img element:

<img src="/image.png" />

you can define another route in your express app and use res.sendFile to serve the stored image:

app.get("/image.png", (req, res) => {
  res.sendFile(path.join(__dirname, "./uploads/image.png"));
});

Java 8 LocalDate Jackson format

Just an update of Christopher answer.

Since the version 2.6.0

<dependency>
    <groupId>com.fasterxml.jackson.datatype</groupId>
    <artifactId>jackson-datatype-jsr310</artifactId>
    <version>2.9.0</version>
</dependency>

Use the JavaTimeModule instead of JSR310Module (deprecated).

@Provider
public class ObjectMapperContextResolver implements ContextResolver<ObjectMapper> {  
    private final ObjectMapper MAPPER;

    public ObjectMapperContextResolver() {
        MAPPER = new ObjectMapper();
        MAPPER.registerModule(new JavaTimeModule());
        MAPPER.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
    }

    @Override
    public ObjectMapper getContext(Class<?> type) {
        return MAPPER;
    }  
}

According to the documentation, the new JavaTimeModule uses same standard settings to default to serialization that does NOT use Timezone Ids, and instead only uses ISO-8601 compliant Timezone offsets.

Behavior may be changed using SerializationFeature.WRITE_DATES_WITH_ZONE_ID

How to set my default shell on Mac?

From Terminal:

  1. Add Fish to /etc/shells, which will require an administrative password:

    sudo echo /usr/local/bin/fish >> /etc/shells
    
  2. Make Fish your default shell with chsh:

    chsh -s /usr/local/bin/fish
    

From System Preferences:

  1. User and Groups ? ctrl-click on Current User ? Advanced Options...

  2. Change Login shell to /usr/local/bin/fish

    login shell

  3. Press OK, log out and in again

SVN "Already Locked Error"

I am not using AnkhSVN but got a similar problem after cancelling a Tortoise SVN update. It left two directories "already locked". Similar to Roman C's solution. Use Get lock to to lock one file in each directory that is "already locked" and then release those locks, then do a cleanup on the highest directory. That seemed to fix the problem.

Prevent PDF file from downloading and printing

Okay, I take back what I commented earlier. Just talked to one of the senior guys in my shop and he said it is possible to lock it down hard. What you can do is convert the pdf to an image/flash/whatever and wrap it in an iFrame. Then, you create another image with 100% transparency and lay it over top the iFrame (not in it) and set it to have a higher Z-value than the iFrame.

What this will do is that if they right click on the 'image' to save it, they will be saving the transparent image instead. And since the image 'overrides' the iFrame, any attempt to use print screen should be shielded by the image, and they should only be able to snapshot the image that doesn't actually exist.

That leaves only one or two ways to get at the file...which requires digging straight into the source code to find the image file inside the iFrame. Still not totally secure, but protected from your average user.

How can I create an utility class?

According to Joshua Bloch (Effective Java), you should use private constructor which always throws exception. That will finally discourage user to create instance of util class.

Marking class abstract is not recommended because is abstract suggests reader that class is designed for inheritance.

Internal Error 500 Apache, but nothing in the logs?

Please Note: The original poster was not specifically asking about PHP. All the php centric answers make large assumptions not relevant to the actual question.

The default error log as opposed to the scripts error logs usually has the (more) specific error. often it will be permissions denied or even an interpreter that can't be found.

This means the fault almost always lies with your script. e.g you uploaded a perl script but didnt give it execute permissions? or perhaps it was corrupted in a linux environment if you write the script in windows and then upload it to the server without the line endings being converted you will get this error.

in perl if you forget

print "content-type: text/html\r\n\r\n";

you will get this error

There are many reasons for it. so please first check your error log and then provide some more information.

The default error log is often in /var/log/httpd/error_log or /var/log/apache2/error.log.

The reason you look at the default error logs (as indicated above) is because errors don't always get posted into the custom error log as defined in the virtual host.

Assumes linux and not necessarily perl

How to do what head, tail, more, less, sed do in Powershell?

more.exe exists on Windows, ports of less are easily found (and the PowerShell Community Extensions, PSCX, includes one).

PowerShell doesn't really provide any alternative to separate programs for either, but for structured data Out-Grid can be helpful.

Head and Tail can both be emulated with Select-Object using the -First and -Last parameters respectively.

Sed functions are all available but structured rather differently. The filtering options are available in Where-Object (or via Foreach-Object and some state for ranges). Other, transforming, operations can be done with Select-Object and Foreach-Object.

However as PowerShell passes (.NET) objects – with all their typed structure, eg. dates remain DateTime instances – rather than just strings, which each command needs to parse itself, much of sed and other such programs are redundant.

AngularJs directive not updating another directive's scope

Just wondering why you are using 2 directives?

It seems like, in this case it would be more straightforward to have a controller as the parent - handle adding the data from your service to its $scope, and pass the model you need from there into your warrantyDirective.

Or for that matter, you could use 0 directives to achieve the same result. (ie. move all functionality out of the separate directives and into a single controller).

It doesn't look like you're doing any explicit DOM transformation here, so in this case, perhaps using 2 directives is overcomplicating things.

Alternatively, have a look at the Angular documentation for directives: http://docs.angularjs.org/guide/directive The very last example at the bottom of the page explains how to wire up dependent directives.

How do you create an asynchronous method in C#?

I don't recommend StartNew unless you need that level of complexity.

If your async method is dependent on other async methods, the easiest approach is to use the async keyword:

private static async Task<DateTime> CountToAsync(int num = 10)
{
  for (int i = 0; i < num; i++)
  {
    await Task.Delay(TimeSpan.FromSeconds(1));
  }

  return DateTime.Now;
}

If your async method is doing CPU work, you should use Task.Run:

private static async Task<DateTime> CountToAsync(int num = 10)
{
  await Task.Run(() => ...);
  return DateTime.Now;
}

You may find my async/await intro helpful.

Convert an array to string

You can join your array using the following:

string.Join(",", Client);

Then you can output anyway you want. You can change the comma to what ever you want, a space, a pipe, or whatever.

MongoDb shuts down with Code 100

Aravind.

It happened with me too because I stopped the MongoDB by the Task Manager.

Creating the C:\data\db folder and starting the MongoDB at C:\Program Files\MongoDB\Server\3.4\bin\mongod.exe worked for me, as cespon suggested, but the MongoDB didn't show any of my Databases previously created.

Then, removing the C:\data\db folder and repairing the installation with the MongoDB installer, I recovered my data and started normally the MongoDB.

(I'm very new with MongoDB, but it helped me solve this problem and recover may previews data).

How do I read the first line of a file using cat?

There is plenty of good answer to this question. Just gonna drop another one into the basket if you wish to do it with lolcat

lolcat FileName.csv | head -n 1

How can I check for IsPostBack in JavaScript?

Create a global variable in and apply the value

<script>
       var isPostBack = <%=Convert.ToString(Page.IsPostBack).ToLower()%>;
</script>

Then you can reference it from elsewhere

Named regular expression group "(?P<group_name>regexp)": what does "P" stand for?

Python Extension. From the Python Docs:

The solution chosen by the Perl developers was to use (?...) as the extension syntax. ? immediately after a parenthesis was a syntax error because the ? would have nothing to repeat, so this didn’t introduce any compatibility problems. The characters immediately after the ? indicate what extension is being used, so (?=foo) is one thing (a positive lookahead assertion) and (?:foo) is something else (a non-capturing group containing the subexpression foo).

Python supports several of Perl’s extensions and adds an extension syntax to Perl’s extension syntax.If the first character after the question mark is a P, you know that it’s an extension that’s specific to Python

https://docs.python.org/3/howto/regex.html

?: ?? Operators Instead Of IF|ELSE

The ternary operator (?:) is not designed for control flow, it's only designed for conditional assignment. If you need to control the flow of your program, use a control structure, such as if/else.

How do I type a TAB character in PowerShell?

TAB has a specific meaning in PowerShell. It's for command completion. So if you enter "getch" and then type a TAB. It changes what you typed into "GetChildItem" (it corrects the case, even though that's unnecessary).

From your question, it looks like TAB completion and command completion would overload the TAB key. I'm pretty sure the PowerShell designers didn't want that.

Get a list of distinct values in List

Jon Skeet has written a library called morelinq which has a DistinctBy() operator. See here for the implementation. Your code would look like

IEnumerable<Note> distinctNotes = Notes.DistinctBy(note => note.Author);

Update: After re-reading your question, Kirk has the correct answer if you're just looking for a distinct set of Authors.

Added sample, several fields in DistinctBy:

res = res.DistinctBy(i => i.Name).DistinctBy(i => i.ProductId).ToList();

Android and Facebook share intent

The usual way

The usual way to create what you're asking for, is to simply do the following:

    Intent intent = new Intent(Intent.ACTION_SEND);
    intent.setType("text/plain");
    intent.putExtra(Intent.EXTRA_TEXT, "The status update text");
    startActivity(Intent.createChooser(intent, "Dialog title text"));

This works without any issues for me.

The alternative way (maybe)

The potential problem with doing this, is that you're also allowing the message to be sent via e-mail, SMS, etc. The following code is something I'm using in an application, that allows the user to send me an e-mail using Gmail. I'm guessing you could try to change it to make it work with Facebook only.

I'm not sure how it responds to any errors or exceptions (I'm guessing that would occur if Facebook is not installed), so you might have to test it a bit.

    try {
        Intent emailIntent = new Intent(android.content.Intent.ACTION_SEND);
        String[] recipients = new String[]{"e-mail address"};
        emailIntent.putExtra(android.content.Intent.EXTRA_EMAIL, recipients);
        emailIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, "E-mail subject");
        emailIntent.putExtra(android.content.Intent.EXTRA_TEXT, "E-mail text");
        emailIntent.setType("plain/text"); // This is incorrect MIME, but Gmail is one of the only apps that responds to it - this might need to be replaced with text/plain for Facebook
        final PackageManager pm = getPackageManager();
        final List<ResolveInfo> matches = pm.queryIntentActivities(emailIntent, 0);
        ResolveInfo best = null;
        for (final ResolveInfo info : matches)
            if (info.activityInfo.packageName.endsWith(".gm") ||
                    info.activityInfo.name.toLowerCase().contains("gmail")) best = info;
                if (best != null)
                    emailIntent.setClassName(best.activityInfo.packageName, best.activityInfo.name);
                startActivity(emailIntent);
    } catch (Exception e) {
        Toast.makeText(this, "Application not found", Toast.LENGTH_SHORT).show();
    }

How to npm install to a specified directory?

In the documentation it's stated: Use the prefix option together with the global option:

The prefix config defaults to the location where node is installed. On most systems, this is /usr/local. On windows, this is the exact location of the node.exe binary. On Unix systems, it's one level up, since node is typically installed at {prefix}/bin/node rather than {prefix}/node.exe.

When the global flag is set, npm installs things into this prefix. When it is not set, it uses the root of the current package, or the current working directory if not in a package already.

(Emphasis by them)

So in your root directory you could install with

npm install --prefix <path/to/prefix_folder> -g

and it will install the node_modules folder into the folder

<path/to/prefix_folder>/lib/node_modules

Understanding inplace=True

In pandas, is inplace = True considered harmful, or not?

TLDR; Yes, yes it is.

  • inplace, contrary to what the name implies, often does not prevent copies from being created, and (almost) never offers any performance benefits
  • inplace does not work with method chaining
  • inplace can lead to SettingWithCopyWarning if used on a DataFrame column, and may prevent the operation from going though, leading to hard-to-debug errors in code

The pain points above are common pitfalls for beginners, so removing this option will simplify the API.


I don't advise setting this parameter as it serves little purpose. See this GitHub issue which proposes the inplace argument be deprecated api-wide.

It is a common misconception that using inplace=True will lead to more efficient or optimized code. In reality, there are absolutely no performance benefits to using inplace=True. Both the in-place and out-of-place versions create a copy of the data anyway, with the in-place version automatically assigning the copy back.

inplace=True is a common pitfall for beginners. For example, it can trigger the SettingWithCopyWarning:

df = pd.DataFrame({'a': [3, 2, 1], 'b': ['x', 'y', 'z']})

df2 = df[df['a'] > 1]
df2['b'].replace({'x': 'abc'}, inplace=True)
# SettingWithCopyWarning: 
# A value is trying to be set on a copy of a slice from a DataFrame

Calling a function on a DataFrame column with inplace=True may or may not work. This is especially true when chained indexing is involved.

As if the problems described above aren't enough, inplace=True also hinders method chaining. Contrast the working of

result = df.some_function1().reset_index().some_function2()

As opposed to

temp = df.some_function1()
temp.reset_index(inplace=True)
result = temp.some_function2()

The former lends itself to better code organization and readability.


Another supporting claim is that the API for set_axis was recently changed such that inplace default value was switched from True to False. See GH27600. Great job devs!

Symfony 2 EntityManager injection in service

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

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


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

1. Use in your services or Controller

<?php

namespace Test\CommonBundle\Services;

use Doctrine\ORM\EntityManagerInterface;

class UserService
{
    private $userRepository;

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

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

2. Create new custom repository

<?php

namespace Test\CommonBundle\Repository;

use Doctrine\ORM\EntityManagerInterface;

class UserRepository
{
    private $repository;

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

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

3. Register services

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

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

Add values to app.config and retrieve them

Try adding a Reference to System.Configuration, you get some of the configuration namespace by referencing the System namespace, adding the reference to System.Configuration should allow you to access ConfigurationManager.

cannot find module "lodash"

I got the error above and after fixing it I got an error for lodash/merge, then I got an error for 'license-check-and-add' then I realized that according to https://accessibilityinsights.io if I ran the below command, it installs all the missing pacakages at once! Then running the yarn build command worked smoothly with a --force parameter with yarn build.

yarn install

yarn build --force

enter image description here

Yarn build --force execution: enter image description here

How do I run a Python script on my web server?

Very simply, you can rename your Python script to "pythonscript.cgi". Post that in your cgi-bin directory, add the appropriate permissions and browse to it.

This is a great link you can start with.

Here's another good one.

Hope that helps.


EDIT (09/12/2015): The second link has long been removed. Replaced it with one that provides information referenced from the original.

Javascript Object push() function

You must make var tempData = new Array();

Push is an Array function.

How to get file_get_contents() to work with HTTPS?

I had the same error. Setting allow_url_include = On in php.ini fixed it for me.

What exactly are iterator, iterable, and iteration?

iterable = [1, 2] 

iterator = iter(iterable)

print(iterator.__next__())   

print(iterator.__next__())   

so,

  1. iterable is an object that can be looped over. e.g. list , string , tuple etc.

  2. using the iter function on our iterable object will return an iterator object.

  3. now this iterator object has method named __next__ (in Python 3, or just next in Python 2) by which you can access each element of iterable.

so, OUTPUT OF ABOVE CODE WILL BE:

1

2

Fixed GridView Header with horizontal and vertical scrolling in asp.net

I was looking for a solution for this for a long time and found most of the answers are not working or not suitable for my situation i also find most of the java script code for that they worked but only with the vertical scroll not with the horizontal scroll and also combination of header and rows doesn't match.

Finally i have found a solution with javascript here is the link bellow :-

scrollable horizontal and vertical grid view with fixed headers

How to get the caller class in Java

You can generate a stack trace and use the informations in the StackTraceElements.

For example an utility class can return you the calling class name :

public class KDebug {
    public static String getCallerClassName() { 
        StackTraceElement[] stElements = Thread.currentThread().getStackTrace();
        for (int i=1; i<stElements.length; i++) {
            StackTraceElement ste = stElements[i];
            if (!ste.getClassName().equals(KDebug.class.getName()) && ste.getClassName().indexOf("java.lang.Thread")!=0) {
                return ste.getClassName();
            }
        }
        return null;
     }
}

If you call KDebug.getCallerClassName() from bar(), you'll get "foo".

Now supposing you want to know the class of the method calling bar (which is more interesting and maybe what you really wanted). You could use this method :

public static String getCallerCallerClassName() { 
    StackTraceElement[] stElements = Thread.currentThread().getStackTrace();
    String callerClassName = null;
    for (int i=1; i<stElements.length; i++) {
        StackTraceElement ste = stElements[i];
        if (!ste.getClassName().equals(KDebug.class.getName())&& ste.getClassName().indexOf("java.lang.Thread")!=0) {
            if (callerClassName==null) {
                callerClassName = ste.getClassName();
            } else if (!callerClassName.equals(ste.getClassName())) {
                return ste.getClassName();
            }
        }
    }
    return null;
 }

Is that for debugging ? If not, there may be a better solution to your problem.

Pycharm: run only part of my Python file

  1. Go to File >> Settings >> Plugins and install the plugin PyCharm cell mode
  2. Go to File >> Settings >> Appearance & Behavior >> Keymap and assign your keyboard shortcuts for Run Cell and Run Cell and go to next

A cell is delimited by ##

Ref https://plugins.jetbrains.com/plugin/7858-pycharm-cell-mode

on change event for file input element

The OnChange event is a good choice. But if a user select the same image, the event will not be triggered because the current value is the same as the previous.

The image is the same with a width changed, for example, and it should be uploaded to the server.

To prevent this problem you could to use the following code:

$(document).ready(function(){
    $("input[type=file]").click(function(){
        $(this).val("");
    });

    $("input[type=file]").change(function(){
        alert($(this).val());
    });
});

How to list processes attached to a shared memory segment in linux?

I wrote a tool called who_attach_shm.pl, it parses /proc/[pid]/maps to get the information. you can download it from github

sample output:

shm attach process list, group by shm key
##################################################################

0x2d5feab4:    /home/curu/mem_dumper /home/curu/playd
0x4e47fc6c:    /home/curu/playd
0x77da6cfe:    /home/curu/mem_dumper /home/curu/playd /home/curu/scand

##################################################################
process shm usage
##################################################################
/home/curu/mem_dumper [2]:    0x2d5feab4 0x77da6cfe
/home/curu/playd [3]:    0x2d5feab4 0x4e47fc6c 0x77da6cfe
/home/curu/scand [1]:    0x77da6cfe

INNER JOIN ON vs WHERE clause

Applying conditional statements in ON / WHERE

Here I have explained the logical query processing steps.


Reference: Inside Microsoft® SQL Server™ 2005 T-SQL Querying
Publisher: Microsoft Press
Pub Date: March 07, 2006
Print ISBN-10: 0-7356-2313-9
Print ISBN-13: 978-0-7356-2313-2
Pages: 640

Inside Microsoft® SQL Server™ 2005 T-SQL Querying

(8)  SELECT (9) DISTINCT (11) TOP <top_specification> <select_list>
(1)  FROM <left_table>
(3)       <join_type> JOIN <right_table>
(2)       ON <join_condition>
(4)  WHERE <where_condition>
(5)  GROUP BY <group_by_list>
(6)  WITH {CUBE | ROLLUP}
(7)  HAVING <having_condition>
(10) ORDER BY <order_by_list>

The first noticeable aspect of SQL that is different than other programming languages is the order in which the code is processed. In most programming languages, the code is processed in the order in which it is written. In SQL, the first clause that is processed is the FROM clause, while the SELECT clause, which appears first, is processed almost last.

Each step generates a virtual table that is used as the input to the following step. These virtual tables are not available to the caller (client application or outer query). Only the table generated by the final step is returned to the caller. If a certain clause is not specified in a query, the corresponding step is simply skipped.

Brief Description of Logical Query Processing Phases

Don't worry too much if the description of the steps doesn't seem to make much sense for now. These are provided as a reference. Sections that come after the scenario example will cover the steps in much more detail.

  1. FROM: A Cartesian product (cross join) is performed between the first two tables in the FROM clause, and as a result, virtual table VT1 is generated.

  2. ON: The ON filter is applied to VT1. Only rows for which the <join_condition> is TRUE are inserted to VT2.

  3. OUTER (join): If an OUTER JOIN is specified (as opposed to a CROSS JOIN or an INNER JOIN), rows from the preserved table or tables for which a match was not found are added to the rows from VT2 as outer rows, generating VT3. If more than two tables appear in the FROM clause, steps 1 through 3 are applied repeatedly between the result of the last join and the next table in the FROM clause until all tables are processed.

  4. WHERE: The WHERE filter is applied to VT3. Only rows for which the <where_condition> is TRUE are inserted to VT4.

  5. GROUP BY: The rows from VT4 are arranged in groups based on the column list specified in the GROUP BY clause. VT5 is generated.

  6. CUBE | ROLLUP: Supergroups (groups of groups) are added to the rows from VT5, generating VT6.

  7. HAVING: The HAVING filter is applied to VT6. Only groups for which the <having_condition> is TRUE are inserted to VT7.

  8. SELECT: The SELECT list is processed, generating VT8.

  9. DISTINCT: Duplicate rows are removed from VT8. VT9 is generated.

  10. ORDER BY: The rows from VT9 are sorted according to the column list specified in the ORDER BY clause. A cursor is generated (VC10).

  11. TOP: The specified number or percentage of rows is selected from the beginning of VC10. Table VT11 is generated and returned to the caller.



Therefore, (INNER JOIN) ON will filter the data (the data count of VT will be reduced here itself) before applying the WHERE clause. The subsequent join conditions will be executed with filtered data which improves performance. After that, only the WHERE condition will apply filter conditions.

(Applying conditional statements in ON / WHERE will not make much difference in few cases. This depends on how many tables you have joined and the number of rows available in each join tables)

selenium - chromedriver executable needs to be in PATH

Try this :

pip install webdriver-manager
from selenium import webdriver
from webdriver_manager.chrome import ChromeDriverManager

driver = webdriver.Chrome(ChromeDriverManager().install())

Enable tcp\ip remote connections to sql server express already installed database with code or script(query)

I tested below code with SQL Server 2008 R2 Express and I believe we should have solution for all 6 steps you outlined. Let's take on them one-by-one:

1 - Enable TCP/IP

We can enable TCP/IP protocol with WMI:

set wmiComputer = GetObject( _
    "winmgmts:" _
    & "\\.\root\Microsoft\SqlServer\ComputerManagement10")
set tcpProtocols = wmiComputer.ExecQuery( _
    "select * from ServerNetworkProtocol " _
    & "where InstanceName = 'SQLEXPRESS' and ProtocolName = 'Tcp'")

if tcpProtocols.Count = 1 then
    ' set tcpProtocol = tcpProtocols(0)
    ' I wish this worked, but unfortunately 
    ' there's no int-indexed Item property in this type

    ' Doing this instead
    for each tcpProtocol in tcpProtocols
        dim setEnableResult
            setEnableResult = tcpProtocol.SetEnable()
            if setEnableResult <> 0 then 
                Wscript.Echo "Failed!"
            end if
    next
end if

2 - Open the right ports in the firewall

I believe your solution will work, just make sure you specify the right port. I suggest we pick a different port than 1433 and make it a static port SQL Server Express will be listening on. I will be using 3456 in this post, but please pick a different number in the real implementation (I feel that we will see a lot of applications using 3456 soon :-)

3 - Modify TCP/IP properties enable a IP address

We can use WMI again. Since we are using static port 3456, we just need to update two properties in IPAll section: disable dynamic ports and set the listening port to 3456:

set wmiComputer = GetObject( _
    "winmgmts:" _
    & "\\.\root\Microsoft\SqlServer\ComputerManagement10")
set tcpProperties = wmiComputer.ExecQuery( _
    "select * from ServerNetworkProtocolProperty " _
    & "where InstanceName='SQLEXPRESS' and " _
    & "ProtocolName='Tcp' and IPAddressName='IPAll'")

for each tcpProperty in tcpProperties
    dim setValueResult, requestedValue

    if tcpProperty.PropertyName = "TcpPort" then
        requestedValue = "3456"
    elseif tcpProperty.PropertyName ="TcpDynamicPorts" then
        requestedValue = ""
    end if

    setValueResult = tcpProperty.SetStringValue(requestedValue)
    if setValueResult = 0 then 
        Wscript.Echo "" & tcpProperty.PropertyName & " set."
    else
        Wscript.Echo "" & tcpProperty.PropertyName & " failed!"
    end if
next

Note that I didn't have to enable any of the individual addresses to make it work, but if it is required in your case, you should be able to extend this script easily to do so.

Just a reminder that when working with WMI, WBEMTest.exe is your best friend!

4 - Enable mixed mode authentication in sql server

I wish we could use WMI again, but unfortunately this setting is not exposed through WMI. There are two other options:

  1. Use LoginMode property of Microsoft.SqlServer.Management.Smo.Server class, as described here.

  2. Use LoginMode value in SQL Server registry, as described in this post. Note that by default the SQL Server Express instance is named SQLEXPRESS, so for my SQL Server 2008 R2 Express instance the right registry key was HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSSQL10_50.SQLEXPRESS\MSSQLServer.

5 - Change user (sa) default password

You got this one covered.

6 - Finally (connect to the instance)

Since we are using a static port assigned to our SQL Server Express instance, there's no need to use instance name in the server address anymore.

SQLCMD -U sa -P newPassword -S 192.168.0.120,3456

Please let me know if this works for you (fingers crossed!).

How to set xampp open localhost:8080 instead of just localhost

you can get loccalhost page by writing localhost/xampp or by writing http://127.0.0.1 you will get the local host page. After starting the apache serve that can be from wamp, xamp or lamp.

How to present UIActionSheet iOS Swift?

Swift :

The sample code given below works both on iPhone and iPad.

 guard let viewRect = sender as? UIView else {
                return
            }

        let cameraSettingsAlert = UIAlertController(title: NSLocalizedString("Please choose a course", comment: ""), message: NSLocalizedString("", comment: ""), preferredStyle: .ActionSheet)
        cameraSettingsAlert.modalPresentationStyle = .Popover

        let photoResolutionAction = UIAlertAction(title: NSLocalizedString("Photo Resolution", comment: ""), style: .Default) { action in

        }
        let cameraOrientationAction = UIAlertAction(title: NSLocalizedString("Camera Orientation", comment: ""), style: .Default) { action in

        }
        let flashModeAction = UIAlertAction(title: NSLocalizedString("Flash Mode", comment: ""), style: .Default) { action in

        }
        let timeStampOnPhotoAction = UIAlertAction(title: NSLocalizedString("Time Stamp on Photo", comment: ""), style: .Default) { action in

        }
        let cancel = UIAlertAction(title: NSLocalizedString("Cancel", comment: ""), style: .Cancel) { action in

        }
        cameraSettingsAlert.addAction(cancel)
        cameraSettingsAlert.addAction(cameraOrientationAction)
        cameraSettingsAlert.addAction(flashModeAction)
        cameraSettingsAlert.addAction(timeStampOnPhotoAction)
        cameraSettingsAlert.addAction(photoResolutionAction)

        if let presenter = cameraSettingsAlert.popoverPresentationController {
            presenter.sourceView = viewRect;
            presenter.sourceRect = viewRect.bounds;
        }
        presentViewController(cameraSettingsAlert, animated: true, completion: nil)

How to validate domain name in PHP?

If you can run shell commands, following is the best way to determine if a domain is registered.

This function returns false, if domain name isn't registered else returns domain name.

function get_domain_name($domain) { 
    //Step 1 - Return false if any shell sensitive chars or space/tab were found
    if(escapeshellcmd($domain)!=$domain || count(explode(".", $domain))<2 || preg_match("/[\s\t]/", $domain)) {
            return false;
    }

    //Step 2 - Get the root domain in-case of subdomain
    $domain = (count(explode(".", $domain))>2 ? strtolower(explode(".", $domain)[count(explode(".", $domain))-2].".".explode(".", $domain)[count(explode(".", $domain))-1]) : strtolower($domain));

    //Step 3 - Run shell command 'dig' to get SOA servers for the domain extension
    $ns = shell_exec(escapeshellcmd("dig +short SOA ".escapeshellarg(explode(".", $domain)[count(explode(".", $domain))-1]))); 

    //Step 4 - Return false if invalid extension (returns NULL), or take the first server address out of output
    if($ns===NULL) {
            return false;
    }
    $ns = (((preg_split('/\s+/', $ns)[0])[strlen(preg_split('/\s+/', $ns)[0])-1]==".") ? substr(preg_split('/\s+/', $ns)[0], 0, strlen(preg_split('/\s+/', $ns)[0])-1) : preg_split('/\s+/', $ns)[0]);

    //Step 5 - Run another dig using the obtained address for our domain, and return false if returned NULL else return the domain name. This assumes an authoritative NS is assigned when a domain is registered, can be improved to filter more accurately.
    $ans = shell_exec(escapeshellcmd("dig +noall +authority ".escapeshellarg("@".$ns)." ".escapeshellarg($domain))); 
    return (($ans===NULL) ? false : ((strpos($ans, $ns)>-1) ? false : $domain));
}

Pros

  1. Works on any domain, while php dns functions may fail on some domains. (my .pro domain failed on php dns)
  2. Works on fresh domains without any dns (like A) records
  3. Unicode friendly

Cons

  1. Usage of shell execution, probably

How do I read text from the clipboard?

I've seen many suggestions to use the win32 module, but Tkinter provides the shortest and easiest method I've seen, as in this post: How do I copy a string to the clipboard on Windows using Python?

Plus, Tkinter is in the python standard library.

When using Spring Security, what is the proper way to obtain current username (i.e. SecurityContext) information in a bean?

I am using the @AuthenticationPrincipal annotation in @Controller classes as well as in @ControllerAdvicer annotated ones. Ex.:

@ControllerAdvice
public class ControllerAdvicer
{
    private static final Logger LOGGER = LoggerFactory.getLogger(ControllerAdvicer.class);


    @ModelAttribute("userActive")
    public UserActive currentUser(@AuthenticationPrincipal UserActive currentUser)
    {
        return currentUser;
    }
}

Where UserActive is the class i use for logged users services, and extends from org.springframework.security.core.userdetails.User. Something like:

public class UserActive extends org.springframework.security.core.userdetails.User
{

    private final User user;

    public UserActive(User user)
    {
        super(user.getUsername(), user.getPasswordHash(), user.getGrantedAuthorities());
        this.user = user;
    }

     //More functions
}

Really easy.

Apply CSS to jQuery Dialog Buttons

If still noting is working for you add the following styles on your page style sheet

.ui-widget-content .ui-state-default {
  border: 0px solid #d3d3d3;
  background: #00ACD6 50% 50% repeat-x;
  font-weight: normal;
  color: #fff;
}

It will change the background color of the dialog buttons.

How to define custom configuration variables in rails

I would suggest good approach how to deal with configuration in your application at all. There are three basic rules:

  • change your configuration not a code;
  • use configurations over conditions;
  • write code that means something.

To have more detailed overview follow this link: Rails configuration in the proper way

Jquery array.push() not working

Your HTML should include quotes for attributes : http://jsfiddle.net/dKWnb/4/

Not required when using a HTML5 doctype - thanks @bazmegakapa

You create the array each time and add a value to it ... its working as expected ?

Moving the array outside of the live() function works fine :

var myarray = []; // more efficient than new Array()
$("#test").live("click",function() {
        myarray.push($("#drop").val());
        alert(myarray);
});

http://jsfiddle.net/dKWnb/5/

Also note that in later versions of jQuery v1.7 -> the live() method is deprecated and replaced by the on() method.

Laravel Mail::send() sending to multiple to or bcc addresses

If you want to send emails simultaneously to all the admins, you can do something like this:

In your .env file add all the emails as comma separated values:

[email protected],[email protected],[email protected]

so when you going to send the email just do this (yes! the 'to' method of message builder instance accepts an array):

So,

$to = explode(',', env('ADMIN_EMAILS'));

and...

$message->to($to);

will now send the mail to all the admins.

Bash integer comparison

This script works!

#/bin/bash
if [[ ( "$#" < 1 ) || ( !( "$1" == 1 ) && !( "$1" == 0 ) ) ]] ; then
    echo this script requires a 1 or 0 as first parameter.
else
    echo "first parameter is $1"
    xinput set-prop 12 "Device Enabled" $0
fi

But this also works, and in addition keeps the logic of the OP, since the question is about calculations. Here it is with only arithmetic expressions:

#/bin/bash
if (( $# )) && (( $1 == 0 || $1 == 1 )); then
    echo "first parameter is $1"
    xinput set-prop 12 "Device Enabled" $0
else
    echo this script requires a 1 or 0 as first parameter.
fi

The output is the same1:

$ ./tmp.sh 
this script requires a 1 or 0 as first parameter.

$ ./tmp.sh 0
first parameter is 0

$ ./tmp.sh 1
first parameter is 1

$ ./tmp.sh 2
this script requires a 1 or 0 as first parameter.

[1] the second fails if the first argument is a string

Ternary operator in PowerShell

Here's an alternative custom function approach:

function Test-TernaryOperatorCondition {
    [CmdletBinding()]
    param (
        [Parameter(ValueFromPipeline = $true, Mandatory = $true)]
        [bool]$ConditionResult
        ,
        [Parameter(Mandatory = $true, Position = 0)]
        [PSObject]$ValueIfTrue
        ,
        [Parameter(Mandatory = $true, Position = 1)]
        [ValidateSet(':')]
        [char]$Colon
        ,
        [Parameter(Mandatory = $true, Position = 2)]
        [PSObject]$ValueIfFalse
    )
    process {
        if ($ConditionResult) {
            $ValueIfTrue
        }
        else {
            $ValueIfFalse
        }
    }
}
set-alias -Name '???' -Value 'Test-TernaryOperatorCondition'

Example

1 -eq 1 |??? 'match' : 'nomatch'
1 -eq 2 |??? 'match' : 'nomatch'

Differences Explained

  • Why is it 3 question marks instead of 1?
    • The ? character is already an alias for Where-Object.
    • ?? is used in other languages as a null coalescing operator, and I wanted to avoid confusion.
  • Why do we need the pipe before the command?
    • Since I'm utilising the pipeline to evaluate this, we still need this character to pipe the condition into our function
  • What happens if I pass in an array?
    • We get a result for each value; i.e. -2..2 |??? 'match' : 'nomatch' gives: match, match, nomatch, match, match (i.e. since any non-zero int evaluates to true; whilst zero evaluates to false).
    • If you don't want that, convert the array to a bool; ([bool](-2..2)) |??? 'match' : 'nomatch' (or simply: [bool](-2..2) |??? 'match' : 'nomatch')

How to automatically insert a blank row after a group of data

Figured it out.

Step 1

Put a new column to the left of column1 and copy+paste the following formula

=B2=B3

=B3=B4

=B4=B5

... all the way to the bottom (assume column B here is column1 in the original question).

This formula evaluates whether or not the next row is a new value in column1. Deopending on the result, you will have TRUE or FALSE. Copy and Paste these results as values and then swap "FALSE" for nil and "TRUE" for 0.5

Step 2

Then add that column full of only 0.5's to the column1 which will yield the following table:

  newcolumn0  |   column1 ("B") |   column2   |  column3
-----------------------------------------------------
              |     1           |     small   |  blue
              |     1           |     small   |  orange
      1.5     |     1           |     small   |  yellow
              |     2           |     med     |  yellow
      2.5     |     2           |     med     |  blue
      3.5     |     3           |     large   |  green
              |     4           |     large   |  green
      4.5     |     4           |     small   |  pink

Step 3

Lastly, copy and paste the values from newcolumn0 right below the values in column1 and then sort the table by column1 and you should have a blank row in between each distinct whole number in column1, with the table something like this:

    newcolumn0   |  column1 ("B")  |   column2       |  column3
---------------------------------------------------------------
                 |     1           |     small   |  blue
                 |     1           |     small   |  orange
        1.5      |     1.5         |             |
                 |     1           |     small   |  yellow
                 |     2           |     med     |  yellow
                 |     2           |     med     |  blue
        2.5      |     2.5         |             |
                 |     3           |     large   |  green
        3.5      |     3.5         |             |
                 |     4           |     large   |  green
                 |     4           |     small   |  pink
        4.5      |     4.5         |             |

Alternative Solutions (still no VBA)

  1. Put a value of 1 Column 1, Row 2 (assume this is A2)
  2. Put this formula in A3 =IF(B3=B2,A2,A2+1) and copy+paste this formula for the rest of column 2
  3. Then copy and paste all the values from column 1 into a new temp excel sheet, remove duplicates, then add 0.5 to all numbers, then paste these values below the values in original spreadsheet below the data in column 1, paste all data in column as values and then sort by that column, delete the temp excel sheet

Running an Excel macro via Python?

Hmm i was having some trouble with that part (yes still xD):

xl.Application.Run("excelsheet.xlsm!macroname.macroname")

cos im not using excel often (same with vb or macros, but i need it to use femap with python) so i finaly resolved it checking macro list: Developer -> Macros: there i saw that: this macroname.macroname should be sheet_name.macroname like in "Macros" list.

(i spend something like 30min-1h trying to solve it, so it may be helpful for noobs like me in excel) xD

What is the best way to test for an empty string in Go?

As per official guidelines and from performance point of view they appear equivalent (ANisus answer), the s != "" would be better due to a syntactical advantage. s != "" will fail at compile time if the variable is not a string, while len(s) == 0 will pass for several other data types.

How to change environment's font size?

You can Zoom In and Zoom Out the entire user interface from the View menu.

Right now i'm using version 1.21.1 and there in view menu you can get the Zoom in and Zoom out option which are the 2nd and 3rd last options. You can do it by using Ctrl + + and Ctrl + -.

You can reset the zoom at any time by selecting Reset Zoom option.

Git pull till a particular commit

I've found the updated answer from this video, the accepted answer didn't work for me.

First clone the latest repo from git (if haven't) using git clone <HTTPs link of the project> (or using SSH) then go to the desire branch using git checkout <branch name> .

Use the command

git log

to check the latest commits. Copy the shal of the particular commit. Then use the command

git fetch origin <Copy paste the shal here>

After pressing enter key. Now use the command

git checkout FETCH_HEAD

Now the particular commit will be available to your local. Change anything and push the code using git push origin <branch name> . That's all. Check the video for reference.

Hiding the address bar of a browser (popup)

You could make the webpage scroll down to a position where you can't see the address bar, and if the user scrolls, the page should return to your set position. In that way, Mobile browsers when scrolled down , will try to guve you full-screen experience. So it will hide the address bar. I don't know the code, someone else might put up the code.

<code> vs <pre> vs <samp> for inline and block code snippets

Show HTML code, as-is, using the (obsolete) <xmp> tag:

_x000D_
_x000D_
<xmp>
<div>
  <input placeholder='write something' value='test'>
</div>
</xmp>
_x000D_
_x000D_
_x000D_

It is very sad this tag has been deprecated, but it does still works on browsers, it it is a bad-ass tag. no need to escape anything inside it. What a joy!


Show HTML code, as-is, using the <textarea> tag:

_x000D_
_x000D_
<textarea readonly rows="4" style="background:none; border:none; resize:none; outline:none; width:100%;">
<div>
  <input placeholder='write something' value='test'>
</div>
</textarea>
_x000D_
_x000D_
_x000D_

PowerShell - Start-Process and Cmdline Switches

I've found using cmd works well as an alternative, especially when you need to pipe the output from the called application (espeically when it doesn't have built in logging, unlike msbuild)

cmd /C "$msbuild $args" >> $outputfile

editing PATH variable on mac

You could try this:

  1. Open the Terminal application. It can be found in the Utilities directory inside the Applications directory.
  2. Type the following: echo 'export PATH=YOURPATHHERE:$PATH' >> ~/.profile, replacing "YOURPATHHERE" with the name of the directory you want to add. Make certain that you use ">>" instead of one ">".
  3. Hit Enter.
  4. Close the Terminal and reopen. Your new Terminal session should now use the new PATH.

-> http://keito.me/tutorials/macosx_path

Embed ruby within URL : Middleman Blog

<%= link_to "http://www.facebook.com/sharer.php?u=" + article_url(article, :text => article.title), :class => "btn btn-primary" do %>   <i class="fa fa-facebook">     Facebook Share    </i> <%end%> 

I am assuming that current_article_url is http://0.0.0.0:4567/link_to_title

Time stamp in the C programming language

If you want to find elapsed time, this method will work as long as you don't reboot the computer between the start and end.

In Windows, use GetTickCount(). Here's how:

DWORD dwStart = GetTickCount();
...
... process you want to measure elapsed time for
...
DWORD dwElapsed = GetTickCount() - dwStart;

dwElapsed is now the number of elapsed milliseconds.

In Linux, use clock() and CLOCKS_PER_SEC to do about the same thing.

If you need timestamps that last through reboots or across PCs (which would need quite good syncronization indeed), then use the other methods (gettimeofday()).

Also, in Windows at least you can get much better than standard time resolution. Usually, if you called GetTickCount() in a tight loop, you'd see it jumping by 10-50 each time it changed. That's because of the time quantum used by the Windows thread scheduler. This is more or less the amount of time it gives each thread to run before switching to something else. If you do a:

timeBeginPeriod(1);

at the beginning of your program or process and a:

timeEndPeriod(1);

at the end, then the quantum will change to 1 ms, and you will get much better time resolution on the GetTickCount() call. However, this does make a subtle change to how your entire computer runs processes, so keep that in mind. However, Windows Media Player and many other things do this routinely anyway, so I don't worry too much about it.

I'm sure there's probably some way to do the same in Linux (probably with much better control, or maybe with sub-millisecond quantums) but I haven't needed to do that yet in Linux.

Rolling or sliding window iterator?

#Importing the numpy library
import numpy as np
arr = np.arange(6) #Sequence
window_size = 3
np.lib.stride_tricks.as_strided(arr, shape= (len(arr) - window_size +1, window_size), 
strides = arr.strides*2)

"""Example output:

  [0, 1, 2]
  [1, 2, 3]
  [2, 3, 4]
  [3, 4, 5]

"""

MySQL SELECT AS combine two columns into one

In case of NULL columns it is better to use IF clause like this which combine the two functions of : CONCAT and COALESCE and uses special chars between the columns in result like space or '_'

SELECT FirstName , LastName , 
IF(FirstName IS NULL AND LastName IS NULL, NULL,' _ ',CONCAT(COALESCE(FirstName ,''), COALESCE(LastName ,''))) 
AS Contact_Phone FROM   TABLE1

How do I get the current date in Cocoa

You need to do something along the lines of the following:

NSDate *now = [NSDate date];
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *components = [calendar components:NSHourCalendarUnit fromDate:now];
NSLog(@"%d", [components hour]);

And so on.

:touch CSS pseudo-class or something similar?

Since mobile doesn't give hover feedback, I want, as a user, to see instant feedback when a link is tapped. I noticed that -webkit-tap-highlight-color is the fastest to respond (subjective).

Add the following to your body and your links will have a tap effect.

body {
    -webkit-tap-highlight-color: #ccc;
}

How do I add a tool tip to a span element?

the "title" attribute will be used as the text for tooltip by the browser, if you want to apply style to it consider using some plugins

How do I indent multiple lines at once in Notepad++?

in Notepad++v6.1.8 (Unicode) it works after removing the QuickText plugin.

How to append multiple items in one line in Python

No.

First off, append is a function, so you can't write append[i+1:i+4] because you're trying to get a slice of a thing that isn't a sequence. (You can't get an element of it, either: append[i+1] is wrong for the same reason.) When you call a function, the argument goes in parentheses, i.e. the round ones: ().

Second, what you're trying to do is "take a sequence, and put every element in it at the end of this other sequence, in the original order". That's spelled extend. append is "take this thing, and put it at the end of the list, as a single item, even if it's also a list". (Recall that a list is a kind of sequence.)

But then, you need to be aware that i+1:i+4 is a special construct that appears only inside square brackets (to get a slice from a sequence) and braces (to create a dict object). You cannot pass it to a function. So you can't extend with that. You need to make a sequence of those values, and the natural way to do this is with the range function.

How to represent multiple conditions in a shell if statement?

you can chain more than 2 conditions too :

if [ \( "$1" = '--usage' \) -o \( "$1" = '' \) -o \( "$1" = '--help' \) ]
then
   printf "\033[2J";printf "\033[0;0H"
   cat << EOF_PRINT_USAGE

   $0 - Purpose: upsert qto http json data to postgres db

   USAGE EXAMPLE:

   $0 -a foo -a bar



EOF_PRINT_USAGE
   exit 1
fi

How to determine if OpenSSL and mod_ssl are installed on Apache2

If you just run openssl in your terminal it should present the openSSL shell. My first clue to knowing that I didn't have mode_ssl was when I got the following error after adding SSLEngine on in my virtualhost file:

Invalid command 'SSLEngine', perhaps misspelled or defined by a module not included in the server configuration

In centos I just had to install it via yum install mod_ssl

What is the right way to check for a null string in Objective-C?

Complete checking of a string for null conditions can be a s follows :<\br>

    if(mystring)
     {
       if([mystring isEqualToString:@""])
        {
          mystring=@"some string";
        }
     }    
    else
     {
        //statements
     }

Disable activity slide-in animation when launching new activity?

Apply

startActivity(new Intent(FirstActivity.this,SecondActivity.class));

then

overridePendingTransition(0, 0);

This will stop the animation.

UITableViewCell Selected Background Color on Multiple Selection

UITableViewCell has an attribute multipleSelectionBackgroundView. https://developer.apple.com/documentation/uikit/uitableviewcell/1623226-selectedbackgroundview

Just create an UIView define the .backgroundColor of your choice and assign it to your cells .multipleSelectionBackgroundView attribute.

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

I hope this helps. Check the link https://jsfiddle.net/awb7gfb1/

<nav>
    <div id="menubar" class=" collapse navbar-collapse row">
        <ul id="dropdownNavbar" class="nav navbar-nav">
            <li class="dropdown">
                <button type="button" class="btn btn-primary dropbtn"><span class="glyphicon glyphicon-time"></span>
                Time Card
                <span class="caret"></span></button>
                <div class="dropdown-content">
                    <a id="showTimeCard" href="#">My Time Card</a>
                    <a href="#">Sub Menu 2</a>
                    <a href="#">Sub Menu 3</a>
                    <a href="#">Sub Menu 4</a>
                    <a href="#">Sub Menu 5</a>
                </div>
            </li>
            <li class="dropdown">
                <button type="button" class="btn btn-primary dropbtn"><span class="glyphicon glyphicon-stats"></span>
                Project
                <span class="caret"></span></button>
                <div class="dropdown-content">
                    <a href="#">Sub Menu 1</a>
                    <a href="#">Sub Menu 2</a>
                    <a href="#">Sub Menu 3</a>
                </div>
            </li>
            <li class="dropdown">
                <button type="button" class="btn btn-primary dropbtn"><span class="glyphicon glyphicon-user"></span>
                HR Links
                <span class="caret"></span></button>
                <div class="dropdown-content">
                    <a href="#">Sub Menu 1</a>
                    <a href="#">Sub Menu 2</a>
                </div>
            </li>
            <li class="dropdown">
                <button type="button" class="btn btn-primary dropbtn">
                <span class="glyphicon glyphicon-screenshot"></span>
                Leave Tracker
                <span class="caret"></span></button>
                <div class="dropdown-content">
                    <a href="#">Sub Menu 1</a>
                    <a href="#">Sub Menu 2</a>
                    <a href="#">Sub Menu 3</a>
                    <a href="#">Sub Menu 4</a>
                </div>
            </li>
            <li class="dropdown">
                <button type="button" class="btn btn-primary dropbtn">
                <span class="glyphicon glyphicon-briefcase"></span>
                Accounts
                <span class="caret"></span></button>
                <div class="dropdown-content">
                    <a href="#">Sub Menu 1</a>
                    <a href="#">Sub Menu 2</a>
                    <a href="#">Sub Menu 3</a>
                    <a href="#">Sub Menu 4</a>
                    <a href="#">Sub Menu 5</a>
                </div>
            </li>
            <li class="dropdown">
                <button type="button" class="btn btn-primary dropbtn">
                <span class="glyphicon glyphicon-headphones"></span>
                Service Desk
                <span class="caret"></span></button>
                <div class="dropdown-content">
                    <a href="#">Sub Menu 1</a>
                    <a href="#">Sub Menu 2</a>
                    <a href="#">Sub Menu 3</a>
                    <a href="#">Sub Menu 4</a>
                </div>
            </li>
            <li class="dropdown">
                <button type="button" class="btn btn-primary dropbtn">
                <span class="glyphicon glyphicon-file"></span>
                Reports
                <span class="caret"></span></button>
                <div class="dropdown-content">
                    <a href="#">Sub Menu 1</a>
                    <a href="#">Sub Menu 2</a>
                    <a href="#">Sub Menu 3</a>
                    <a href="#">Sub Menu 4</a>
                    <a href="#">Sub Menu 5</a>
                </div>
            </li>
            <li class="dropdown">
                <button type="button" class="btn btn-primary dropbtn">
                <span class="glyphicon glyphicon-cog"></span>
                Settings
                <span class="caret"></span></button>
                <div class="dropdown-content">
                    <a href="#">Sub Menu 1</a>
                    <a href="#">Sub Menu 2</a>
                    <a href="#">Sub Menu 3</a>
                </div>
            </li>
        </ul>
    </div>
</nav>

And the CSS

.dropdown {
    float: left;
    padding-right: 1px;
}

.dropbtn{
    border: 0px;
    height: 30px;
    border-radius: 0px 10px;
}
li button, .dropbtn {
    display: inline-block;
    color: white;
    text-align: center;
}

li button:hover, .dropdown:hover .dropbtn {
    background-color: #12A5F4;
}

.dropbtn.active {
    background: #12A5F4;
}

.dropdown-content {
    display: none;
    position: absolute;
    background-color: #e8f3f4;
    min-width: 100%;
    box-shadow: 0px 8px 16px 0px rgba(0, 0, 0, 0.1);
    z-index: 10;
}

.navbar-header{
    overflow: visible;
    z-index: 1;
}

.dropdown-content a {
    color: black;
    padding: 5px 10px;
    display: block;
    text-align: left;
}

.dropdown-content a:hover {
    background-color: #d8dee2
}

.dropdown:hover .dropdown-content {
    display: block;
}

#menubar{
    padding-top: 5px;
    overflow: visible;
    z-index: 10;
    padding-left: 0px;
    padding-right: 0px;
    margin: 0px;
}

#dropdownNavbar{
    margin: 0px;
}

.navbar-toggle{
    background-color: #3382d5;
}
.navbar-toggle span{
    background-color: white;
}

How do I syntax check a Bash script without running it?

I actually check all bash scripts in current dir for syntax errors WITHOUT running them using find tool:

Example:

find . -name '*.sh' -exec bash -n {} \;

If you want to use it for a single file, just edit the wildcard with the name of the file.

Getting request payload from POST request in Java servlet

Simple answer:
Use getReader() to read the body of the request

More info:
There are two methods for reading the data in the body:

  1. getReader() returns a BufferedReader that will allow you to read the body of the request.

  2. getInputStream() returns a ServletInputStream if you need to read binary data.

Note from the docs: "[Either method] may be called to read the body, not both."

Set a persistent environment variable from cmd.exe

Indeed SET TEST_VARIABLE=value works for current process only, so SETX is required. A quick example for permanently storing an environment variable at user level.

  1. In cmd, SETX TEST_VARIABLE etc. Not applied yet (echo %TEST_VARIABLE% shows %TEST_VARIABLE%,
  2. Quick check: open cmd, echo %TEST_VARIABLE% shows etc.
  3. GUI check: System Properties -> Advanced -> Environment variables -> User variables for -> you should see Varible TEST_VARIABLE with value etc.

How to concatenate strings in django templates?

extends has no facility for this. Either put the entire template path in a context variable and use that, or copy the exist template tag and modify it appropriately.

How to load an ImageView by URL in Android?

    private Bitmap getImageBitmap(String url) {
        Bitmap bm = null;
        try {
            URL aURL = new URL(url);
            URLConnection conn = aURL.openConnection();
            conn.connect();
            InputStream is = conn.getInputStream();
            BufferedInputStream bis = new BufferedInputStream(is);
            bm = BitmapFactory.decodeStream(bis);
            bis.close();
            is.close();
       } catch (IOException e) {
           Log.e(TAG, "Error getting bitmap", e);
       }
       return bm;
    } 

jQuery selector for id starts with specific text

If all your divs start with editDialog as you stated, then you can use the following selector:

$("div[id^='editDialog']")

Or you could use a class selector instead if it's easier for you

<div id="editDialog-0" class="editDialog">...</div>

$(".editDialog")

How to perform update operations on columns of type JSONB in Postgres 9.4

If you're able to upgrade to Postgresql 9.5, the jsonb_set command is available, as others have mentioned.

In each of the following SQL statements, I've omitted the where clause for brevity; obviously, you'd want to add that back.

Update name:

UPDATE test SET data = jsonb_set(data, '{name}', '"my-other-name"');

Replace the tags (as oppose to adding or removing tags):

UPDATE test SET data = jsonb_set(data, '{tags}', '["tag3", "tag4"]');

Replacing the second tag (0-indexed):

UPDATE test SET data = jsonb_set(data, '{tags,1}', '"tag5"');

Append a tag (this will work as long as there are fewer than 999 tags; changing argument 999 to 1000 or above generates an error. This no longer appears to be the case in Postgres 9.5.3; a much larger index can be used):

UPDATE test SET data = jsonb_set(data, '{tags,999999999}', '"tag6"', true);

Remove the last tag:

UPDATE test SET data = data #- '{tags,-1}'

Complex update (delete the last tag, insert a new tag, and change the name):

UPDATE test SET data = jsonb_set(
    jsonb_set(data #- '{tags,-1}', '{tags,999999999}', '"tag3"', true), 
    '{name}', '"my-other-name"');

It's important to note that in each of these examples, you're not actually updating a single field of the JSON data. Instead, you're creating a temporary, modified version of the data, and assigning that modified version back to the column. In practice, the result should be the same, but keeping this in mind should make complex updates, like the last example, more understandable.

In the complex example, there are three transformations and three temporary versions: First, the last tag is removed. Then, that version is transformed by adding a new tag. Next, the second version is transformed by changing the name field. The value in the data column is replaced with the final version.

Java - How Can I Write My ArrayList to a file, and Read (load) that file to the original ArrayList?

To save and load an arraylist of public static ArrayList data = new ArrayList ();

I used (to write)...

static void saveDatabase() {
try {

        FileOutputStream fos = new FileOutputStream("mydb.fil");
        ObjectOutputStream oos = new ObjectOutputStream(fos);
        oos.writeObject(data);
        oos.close();
        databaseIsSaved = true;         

    }
catch (IOException e) {
        e.printStackTrace();
}

} // End of saveDatabase

And used (to read) ...

static void loadDatabase() {

try {           
        FileInputStream fis = new FileInputStream("mydb.fil");
        ObjectInputStream ois = new ObjectInputStream(fis);         
        data = (ArrayList<User>)ois.readObject();
        ois.close();            
    }       
catch (IOException e) {
        System.out.println("***catch ERROR***");
        e.printStackTrace();

    }       
catch (ClassNotFoundException e) {
        System.out.println("***catch ERROR***");
        e.printStackTrace();
    }   
} // End of loadDatabase 

Reflection: How to Invoke Method with parameters

Change "methodInfo" to "classInstance", just like in the call with the null parameter array.

  result = methodInfo.Invoke(classInstance, parametersArray);

How to create a fixed-size array of objects

For now, semantically closest one would be a tuple with fixed number of elements.

typealias buffer = (
    SKSpriteNode, SKSpriteNode, SKSpriteNode, SKSpriteNode,
    SKSpriteNode, SKSpriteNode, SKSpriteNode, SKSpriteNode,
    SKSpriteNode, SKSpriteNode, SKSpriteNode, SKSpriteNode,
    SKSpriteNode, SKSpriteNode, SKSpriteNode, SKSpriteNode,
    SKSpriteNode, SKSpriteNode, SKSpriteNode, SKSpriteNode,
    SKSpriteNode, SKSpriteNode, SKSpriteNode, SKSpriteNode,
    SKSpriteNode, SKSpriteNode, SKSpriteNode, SKSpriteNode,
    SKSpriteNode, SKSpriteNode, SKSpriteNode, SKSpriteNode,
    SKSpriteNode, SKSpriteNode, SKSpriteNode, SKSpriteNode,
    SKSpriteNode, SKSpriteNode, SKSpriteNode, SKSpriteNode,
    SKSpriteNode, SKSpriteNode, SKSpriteNode, SKSpriteNode,
    SKSpriteNode, SKSpriteNode, SKSpriteNode, SKSpriteNode,
    SKSpriteNode, SKSpriteNode, SKSpriteNode, SKSpriteNode,
    SKSpriteNode, SKSpriteNode, SKSpriteNode, SKSpriteNode,
    SKSpriteNode, SKSpriteNode, SKSpriteNode, SKSpriteNode,
    SKSpriteNode, SKSpriteNode, SKSpriteNode, SKSpriteNode)

But this is (1) very uncomfortable to use and (2) memory layout is undefined. (at least unknown to me)

How to close a GUI when I push a JButton?

Add your button:

JButton close = new JButton("Close");

Add an ActionListener:

close.addActionListner(new CloseListener());

Add a class for the Listener implementing the ActionListener interface and override its main function:

private class CloseListener implements ActionListener{
    @Override
    public void actionPerformed(ActionEvent e) {
        //DO SOMETHING
        System.exit(0);
    }
}

This might be not the best way, but its a point to start. The class for example can be made public and not as a private class inside another one.

jQuery Refresh/Reload Page if Ajax Success after time

In your ajax success callback do this:

success: function(data){
   if(data.success == true){ // if true (1)
      setTimeout(function(){// wait for 5 secs(2)
           location.reload(); // then reload the page.(3)
      }, 5000); 
   }
}

As you want to reload the page after 5 seconds, then you need to have a timeout as suggested in the answer.

Default username password for Tomcat Application Manager

To reset your keyring.

  1. Go into your home folder.

  2. Press ctrl & h to show your hidden folders.

  3. Now look in your .gnome2/keyrings directory.

  4. Find the default.keyring file.

  5. Move that file to a different folder.

  6. Once done, reboot your computer.

Pandas KeyError: value not in index

Use reindex to get all columns you need. It'll preserve the ones that are already there and put in empty columns otherwise.

p = p.reindex(columns=['1Sun', '2Mon', '3Tue', '4Wed', '5Thu', '6Fri', '7Sat'])

So, your entire code example should look like this:

df = pd.read_csv(CsvFileName)

p = df.pivot_table(index=['Hour'], columns='DOW', values='Changes', aggfunc=np.mean).round(0)
p.fillna(0, inplace=True)

columns = ["1Sun", "2Mon", "3Tue", "4Wed", "5Thu", "6Fri", "7Sat"]
p = p.reindex(columns=columns)
p[columns] = p[columns].astype(int)

Differences between git pull origin master & git pull origin/master

git pull origin master will pull changes from the origin remote, master branch and merge them to the local checked-out branch.

git pull origin/master will pull changes from the locally stored branch origin/master and merge that to the local checked-out branch. The origin/master branch is essentially a "cached copy" of what was last pulled from origin, which is why it's called a remote branch in git parlance. This might be somewhat confusing.

You can see what branches are available with git branch and git branch -r to see the "remote branches".

Django CSRF check failing with an Ajax POST request

Using Django 3.1.1 and all solutions I tried failed. However, adding the "csrfmiddlewaretoken" key to my POST body worked. Here's the call I made:

$.post(url, {
  csrfmiddlewaretoken: window.CSRF_TOKEN,
  method: "POST",
  data: JSON.stringify(data),
  dataType: 'JSON',
});

And in the HTML template:

<script type="text/javascript">
  window.CSRF_TOKEN = "{{ csrf_token }}";
</script>

How do I install chkconfig on Ubuntu?

sysv-rc-conf is an alternate option for Ubuntu.

sudo apt-get install sysv-rc-conf

sysv-rc-conf --list xxxx

How to convert webpage into PDF by using Python

thanks to below posts, and I am able to add on the webpage link address to be printed and present time on the PDF generated, no matter how many pages it has.

Add text to Existing PDF using Python

https://github.com/disflux/django-mtr/blob/master/pdfgen/doc_overlay.py

To share the script as below:

import time
from pyPdf import PdfFileWriter, PdfFileReader
import StringIO
from reportlab.pdfgen import canvas
from reportlab.lib.pagesizes import letter
from xhtml2pdf import pisa
import sys 
from PyQt4.QtCore import *
from PyQt4.QtGui import * 
from PyQt4.QtWebKit import * 

url = 'http://www.yahoo.com'
tem_pdf = "c:\\tem_pdf.pdf"
final_file = "c:\\younameit.pdf"

app = QApplication(sys.argv)
web = QWebView()
#Read the URL given
web.load(QUrl(url))
printer = QPrinter()
#setting format
printer.setPageSize(QPrinter.A4)
printer.setOrientation(QPrinter.Landscape)
printer.setOutputFormat(QPrinter.PdfFormat)
#export file as c:\tem_pdf.pdf
printer.setOutputFileName(tem_pdf)

def convertIt():
    web.print_(printer)
    QApplication.exit()

QObject.connect(web, SIGNAL("loadFinished(bool)"), convertIt)

app.exec_()
sys.exit

# Below is to add on the weblink as text and present date&time on PDF generated

outputPDF = PdfFileWriter()
packet = StringIO.StringIO()
# create a new PDF with Reportlab
can = canvas.Canvas(packet, pagesize=letter)
can.setFont("Helvetica", 9)
# Writting the new line
oknow = time.strftime("%a, %d %b %Y %H:%M")
can.drawString(5, 2, url)
can.drawString(605, 2, oknow)
can.save()

#move to the beginning of the StringIO buffer
packet.seek(0)
new_pdf = PdfFileReader(packet)
# read your existing PDF
existing_pdf = PdfFileReader(file(tem_pdf, "rb"))
pages = existing_pdf.getNumPages()
output = PdfFileWriter()
# add the "watermark" (which is the new pdf) on the existing page
for x in range(0,pages):
    page = existing_pdf.getPage(x)
    page.mergePage(new_pdf.getPage(0))
    output.addPage(page)
# finally, write "output" to a real file
outputStream = file(final_file, "wb")
output.write(outputStream)
outputStream.close()

print final_file, 'is ready.'

Effect of NOLOCK hint in SELECT statements

It will be faster because it doesnt have to wait for locks

Renaming Columns in an SQL SELECT Statement

You can alias the column names one by one, like so

SELECT col1 as `MyNameForCol1`, col2 as `MyNameForCol2` 
FROM `foobar`

Edit You can access INFORMATION_SCHEMA.COLUMNS directly to mangle a new alias like so. However, how you fit this into a query is beyond my MySql skills :(

select CONCAT('Foobar_', COLUMN_NAME)
from INFORMATION_SCHEMA.COLUMNS 
where TABLE_NAME = 'Foobar'

How can I get the Google cache age of any URL or web page?

This one good also to view cachepage http://www.cachepage.net

  1. Cache page view via google: webcache.googleusercontent.com/search?q=cache: Your url

  2. Cache page view via archive.org: web.archive.org/web/*/Your url

Is Tomcat running?

Try this command

ps -ef | awk '/[t]omcat/{print $2}' 

It will return the pid if tomcat is running.

Why is there no Constant feature in Java?

const in C++ does not mean that a value is a constant.

const in C++ implies that the client of a contract undertakes not to alter its value.

Whether the value of a const expression changes becomes more evident if you are in an environment which supports thread based concurrency.

As Java was designed from the start to support thread and lock concurrency, it didn't add to confusion by overloading the term to have the semantics that final has.

eg:

#include <iostream>

int main ()
{
    volatile const int x = 42;

    std::cout << x << std::endl;

    *const_cast<int*>(&x) = 7;

    std::cout << x << std::endl;

    return 0;
}

outputs 42 then 7.

Although x marked as const, as a non-const alias is created, x is not a constant. Not every compiler requires volatile for this behaviour (though every compiler is permitted to inline the constant)

With more complicated systems you get const/non-const aliases without use of const_cast, so getting into the habit of thinking that const means something won't change becomes more and more dangerous. const merely means that your code can't change it without a cast, not that the value is constant.

GROUP BY and COUNT in PostgreSQL

I think you just need COUNT(DISTINCT post_id) FROM votes.

See "4.2.7. Aggregate Expressions" section in http://www.postgresql.org/docs/current/static/sql-expressions.html.

EDIT: Corrected my careless mistake per Erwin's comment.

Android Studio gradle takes too long to build

Recommended Reading: How I save 5h/week on Gradle builds!

According to this excellent post you should try to optimized the following:

  • Gradle Daemon
  • Parallel Project Execution
  • Configure projects on demand
  • Modules are expensive...

Programmatically set image to UIImageView with Xcode 6.1/Swift

OK, got it working with this (creating the UIImageView programmatically):

var imageViewObject :UIImageView

imageViewObject = UIImageView(frame:CGRectMake(0, 0, 600, 600))

imageViewObject.image = UIImage(named:"afternoon")

self.view.addSubview(imageViewObject)

self.view.sendSubviewToBack(imageViewObject)

How do you save/store objects in SharedPreferences on Android?

If your Object is complex I'd suggest to Serialize/XML/JSON it and save those contents to the SD card. You can find additional info on how to save to external storage here: http://developer.android.com/guide/topics/data/data-storage.html#filesExternal

How to fluently build JSON in Java?

The reference implementation includes a fluent interface. Check out JSONWriter and its toString-implementing subclass JSONStringer

Add Variables to Tuple

" once the info is added to the DB, should I delete the tuple? i mean i dont need the tuple anymore."

No.

Generally, there's no reason to delete anything. There are some special cases for deleting, but they're very, very rare.

Simply define a narrow scope (i.e., a function definition or a method function in a class) and the objects will be garbage collected at the end of the scope.

Don't worry about deleting anything.

[Note. I worked with a guy who -- in addition to trying to delete objects -- was always writing "reset" methods to clear them out. Like he was going to save them and reuse them. Also a silly conceit. Just ignore the objects you're no longer using. If you define your functions in small-enough blocks of code, you have nothing more to think about.]

Java creating .jar file

Often you need to put more into the manifest than what you get with the -e switch, and in that case, the syntax is:

jar -cvfm myJar.jar myManifest.txt myApp.class

Which reads: "create verbose jarFilename manifestFilename", followed by the files you want to include.

Note that the name of the manifest file you supply can be anything, as jar will automatically rename it and put it into the right place within the jar file.

load iframe in bootstrap modal

I came across this implementation in Codepen. I hope you find it helpful.

this.on('hidden.bs.modal', function(){
      $(this).find('iframe').html("").attr("src", "");
    });

How can I color a UIImage in Swift?

Swift 3 version with scale and Orientation from @kuzdu answer

extension UIImage {

    func mask(_ color: UIColor) -> UIImage? {
        let maskImage = cgImage!

        let width = (cgImage?.width)!
        let height = (cgImage?.height)!
        let bounds = CGRect(x: 0, y: 0, width: width, height: height)

        let colorSpace = CGColorSpaceCreateDeviceRGB()
        let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.premultipliedLast.rawValue)
        let context = CGContext(data: nil, width: Int(width), height: Int(height), bitsPerComponent: 8, bytesPerRow: 0, space: colorSpace, bitmapInfo: bitmapInfo.rawValue)!

        context.clip(to: bounds, mask: maskImage)
        context.setFillColor(color.cgColor)
        context.fill(bounds)

        if let cgImage = context.makeImage() {
            let coloredImage = UIImage.init(cgImage: cgImage, scale: scale, orientation: imageOrientation)
            return coloredImage
        } else {
            return nil
        }
    }
}

How to split a string after specific character in SQL Server and update this value to specific column

From: http://www.sql-server-helper.com/error-messages/msg-536.aspx

To use function LEFT if not all data is in the form '1/12' you need this in the second line above:

Set Col2 = LEFT(Col1, ISNULL(NULLIF(CHARINDEX('/', Col1) - 1, -1), LEN(Col1)))

How get permission for camera in android.(Specifically Marshmallow)

check using this
if (ContextCompat.checkSelfPermission(this, android.Manifest.permission.CAMERA)
            == PackageManager.PERMISSION_DENIED)

and

Why do symbols like apostrophes and hyphens get replaced with black diamonds on my website?

What I really don't understand with this kind of problem is that the html page I ran as a local file displayed perfectly in Chromium browser, but as soon as I uploaded it to my website, it produced this error.

Even stranger, it displayed perfectly in the Vivaldi browser whether displayed from the local or remote file.

Is this something to do with the way Chromium reads the character set? But why only with a remote file?

I fixed the problem by retyping the text in a simple text editor and making sure the single quote mark was the one I used.

How to remove duplicate white spaces in string using Java?

Like this:

yourString = yourString.replaceAll("\\s+", " ");

For example

System.out.println("lorem  ipsum   dolor \n sit.".replaceAll("\\s+", " "));

outputs

lorem ipsum dolor sit.

What does that \s+ mean?

\s+ is a regular expression. \s matches a space, tab, new line, carriage return, form feed or vertical tab, and + says "one or more of those". Thus the above code will collapse all "whitespace substrings" longer than one character, with a single space character.


Source: Java: Removing duplicate white spaces in strings

Pointer vs. Reference

Pointers:

  • Can be assigned nullptr (or NULL).
  • At the call site, you must use & if your type is not a pointer itself, making explicitly you are modifying your object.
  • Pointers can be rebound.

References:

  • Cannot be null.
  • Once bound, cannot change.
  • Callers don't need to explicitly use &. This is considered sometimes bad because you must go to the implementation of the function to see if your parameter is modified.

OSX El Capitan: sudo pip install OSError: [Errno: 1] Operation not permitted

I have python2.7 installed via brew and the following solved my problem

brew install numpy

It installs python3, but it still works and sets it up for 2.7 as well.

How do you do exponentiation in C?

or you could just write the power function, with recursion as a added bonus

int power(int x, int y){
      if(y == 0)
        return 1;
     return (x * power(x,y-1) );
    }

yes,yes i know this is less effecient space and time complexity but recursion is just more fun!!

Interpreting "condition has length > 1" warning from `if` function

The way I cam across this question was when I tried doing something similar where I was defining a function and it was being called with the array like others pointed out

You could do something like this however for this scenarios its less elegant compared to Sven's method.

sapply(a, function(x) afunc(x))

afunc<-function(a){
  if (a>0){
    a/sum(a)
  }
  else 1
}

How To Launch Git Bash from DOS Command Line?

If you want to launch from a batch file:

  • for x86

    start "" "%SYSTEMDRIVE%\Program Files (x86)\Git\bin\sh.exe" --login
    
  • for x64

    start "" "%PROGRAMFILES%\Git\bin\sh.exe" --login
    

Checking the form field values before submitting that page

You can simply make the start_date required using

<input type="submit" value="Submit" required />

You don't even need the checkform() then.

Thanks

how to add the missing RANDR extension

First off, Xvfb doesn't read configuration from xorg.conf. Xvfb is a variant of the KDrive X servers and like all members of that family gets its configuration from the command line.

It is true that XRandR and Xinerama are mutually exclusive, but in the case of Xvfb there's no Xinerama in the first place. You can enable the XRandR extension by starting Xvfb using at least the following command line options

Xvfb +extension RANDR [further options]

Adjust UILabel height depending on the text

Adding to the above answers:

This can be easily achieved via storyboard.

  1. Set constraint for UILabel.(In my case I did top, left and fixed width)
  2. Set Number of line to 0 in Attribute Inspector
  3. Set Line Break to WordWrap in Attribute Inspector.

UILabel Height Adjust

Postgresql SELECT if string contains

I personally prefer the simpler syntax of the ~ operator.

SELECT id FROM TAG_TABLE WHERE 'aaaaaaaa' ~ tag_name;

Worth reading through Difference between LIKE and ~ in Postgres to understand the difference. `

SQL LIKE condition to check for integer?

In PostreSQL you can use SIMILAR TO operator (more):

-- only digits
select * from books where title similar to '^[0-9]*$';
-- start with digit
select * from books where title similar to '^[0-9]%$';

How can I reuse a navigation bar on multiple pages?

This is what helped me. My navigation bar is in the body tag. Entire code for navigation bar is in nav.html file (without any html or body tag, only the code for navigation bar). In the target page, this goes in the head tag:

<script src="https://code.jquery.com/jquery-1.10.2.js"></script>

Then in the body tag, a container is made with an unique id and a javascript block to load the nav.html into the container, as follows:

<!--Navigation bar-->
<div id="nav-placeholder">

</div>

<script>
$(function(){
  $("#nav-placeholder").load("nav.html");
});
</script>
<!--end of Navigation bar-->

How to prevent scrollbar from repositioning web page?

Contrary to the accepted answer which suggests a permanent scroll bar on the browser window even if the content doesn't overflow the screen, I would prefer using:

html{
  height:101%;
}

This is because the appearance of scroll bar makes more sense if the content actually overflows.

This makes more sense than this.

Android Camera Preview Stretched

F1Sher's solution is nice but sometimes doesn't work. Particularly, when your surfaceView doesn't cover whole screen. In this case you need to override onMeasure() method. I have copied my code here for your reference.

Since I measured surfaceView based on width then I have little bit white gap at the end of my screen that I filled it by design. You are able to fix this issue if you keep height and increase width by multiply it to ratio. However, it will squish surfaceView slightly.

public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {

    private static final String TAG = "CameraPreview";

    private Context mContext;
    private SurfaceHolder mHolder;
    private Camera mCamera;
    private List<Camera.Size> mSupportedPreviewSizes;
    private Camera.Size mPreviewSize;

    public CameraPreview(Context context, Camera camera) {
        super(context);
        mContext = context;
        mCamera = camera;

        // supported preview sizes
        mSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes();
        for(Camera.Size str: mSupportedPreviewSizes)
                Log.e(TAG, str.width + "/" + str.height);

        // Install a SurfaceHolder.Callback so we get notified when the
        // underlying surface is created and destroyed.
        mHolder = getHolder();
        mHolder.addCallback(this);
        // deprecated setting, but required on Android versions prior to 3.0
        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    public void surfaceCreated(SurfaceHolder holder) {
        // empty. surfaceChanged will take care of stuff
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        // empty. Take care of releasing the Camera preview in your activity.
    }

    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
        Log.e(TAG, "surfaceChanged => w=" + w + ", h=" + h);
        // If your preview can change or rotate, take care of those events here.
        // Make sure to stop the preview before resizing or reformatting it.
        if (mHolder.getSurface() == null){
            // preview surface does not exist
            return;
        }

        // stop preview before making changes
        try {
            mCamera.stopPreview();
        } catch (Exception e){
            // ignore: tried to stop a non-existent preview
        }

        // set preview size and make any resize, rotate or reformatting changes here
        // start preview with new settings
        try {
            Camera.Parameters parameters = mCamera.getParameters();
            parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
            mCamera.setParameters(parameters);
            mCamera.setDisplayOrientation(90);
            mCamera.setPreviewDisplay(mHolder);
            mCamera.startPreview();

        } catch (Exception e){
            Log.d(TAG, "Error starting camera preview: " + e.getMessage());
        }
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
        final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);

        if (mSupportedPreviewSizes != null) {
            mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height);
        }

        if (mPreviewSize!=null) {
            float ratio;
            if(mPreviewSize.height >= mPreviewSize.width)
                ratio = (float) mPreviewSize.height / (float) mPreviewSize.width;
            else
                ratio = (float) mPreviewSize.width / (float) mPreviewSize.height;

            // One of these methods should be used, second method squishes preview slightly
            setMeasuredDimension(width, (int) (width * ratio));
  //        setMeasuredDimension((int) (width * ratio), height);
        }
    }

    private Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) {
        final double ASPECT_TOLERANCE = 0.1;
        double targetRatio = (double) h / w;

        if (sizes == null)
            return null;

        Camera.Size optimalSize = null;
        double minDiff = Double.MAX_VALUE;

        int targetHeight = h;

        for (Camera.Size size : sizes) {
            double ratio = (double) size.height / size.width;
            if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE)
                continue;

            if (Math.abs(size.height - targetHeight) < minDiff) {
                optimalSize = size;
                minDiff = Math.abs(size.height - targetHeight);
            }
        }

        if (optimalSize == null) {
            minDiff = Double.MAX_VALUE;
            for (Camera.Size size : sizes) {
                if (Math.abs(size.height - targetHeight) < minDiff) {
                    optimalSize = size;
                    minDiff = Math.abs(size.height - targetHeight);
                }
            }
        }

        return optimalSize;
    }
}

GROUP BY + CASE statement

Aliases can be used only if they were introduced in the preceding step. So aliases in the SELECT clause can be used in the ORDER BY but not the GROUP BY clause.

Reference: Microsoft T-SQL Documentation for further reading.

FROM
ON
JOIN
WHERE
GROUP BY
WITH CUBE or WITH ROLLUP
HAVING
SELECT
DISTINCT
ORDER BY
TOP

Hope this helps.

What's the difference between deadlock and livelock?

Imagine you've thread A and thread B. They are both synchronised on the same object and inside this block there's a global variable they are both updating;

static boolean commonVar = false;
Object lock = new Object;

...

void threadAMethod(){
    ...
    while(commonVar == false){
         synchornized(lock){
              ...
              commonVar = true
         }
    }
}

void threadBMethod(){
    ...
    while(commonVar == true){
         synchornized(lock){
              ...
              commonVar = false
         }
    }
}

So, when thread A enters in the while loop and holds the lock, it does what it has to do and set the commonVar to true. Then thread B comes in, enters in the while loop and since commonVar is true now, it is be able to hold the lock. It does so, executes the synchronised block, and sets commonVar back to false. Now, thread A again gets it's new CPU window, it was about to quit the while loop but thread B has just set it back to false, so the cycle repeats over again. Threads do something (so they're not blocked in the traditional sense) but for pretty much nothing.

It maybe also nice to mention that livelock does not necessarily have to appear here. I'm assuming that the scheduler favours the other thread once the synchronised block finish executing. Most of the time, I think it's a hard-to-hit expectation and depends on many things happening under the hood.

Replacing values from a column using a condition in R

I arrived here from a google search, since my other code is 'tidy' so leaving the 'tidy' way for anyone who else who may find it useful

library(dplyr)
iris %>% 
  mutate(Species = ifelse(as.character(Species) == "virginica", "newValue", as.character(Species)))

How to check heap usage of a running JVM from the command line?

If you start execution with gc logging turned on you get the info on file. Otherwise 'jmap -heap ' will give you what you want. See the jmap doc page for more.

Please note that jmap should not be used in a production environment unless absolutely needed as the tool halts the application to be able to determine actual heap usage. Usually this is not desired in a production environment.

Top 1 with a left join

Use OUTER APPLY instead of LEFT JOIN:

SELECT u.id, mbg.marker_value 
FROM dps_user u
OUTER APPLY 
    (SELECT TOP 1 m.marker_value, um.profile_id
     FROM dps_usr_markers um (NOLOCK)
         INNER JOIN dps_markers m (NOLOCK) 
             ON m.marker_id= um.marker_id AND 
                m.marker_key = 'moneyBackGuaranteeLength'
     WHERE um.profile_id=u.id 
     ORDER BY m.creation_date
    ) AS MBG
WHERE u.id = 'u162231993';

Unlike JOIN, APPLY allows you to reference the u.id inside the inner query.

Cross Browser Flash Detection in Javascript

SWFObject is very reliable. I have used it without trouble for quite a while.

What is the difference between Bootstrap .container and .container-fluid classes?

From a display perspective .container gives you more control over the what the users are seeing, and makes it easier to see what the users will see as you only have 4 variations of display (5 in the case of bootstrap 5) because the sizes relate to the same as the grid sizes. e.g. .col-xs, .col-sm, .col, and .col-lg.

What this means, is that when you are doing user testing if you test on a displays with the 4 different sizes you see all the veriations in display.

When using .container-fluid because the witdh is related to the viewport width the display is dynamic, so the varations are much greater and users with very large screens or uncommon screen widths may see results you weren't expecting.

Measuring function execution time in R

The package "tictoc" gives you a very simple way of measuring execution time. The documentation is in: https://cran.fhcrc.org/web/packages/tictoc/tictoc.pdf.

install.packages("tictoc")
require(tictoc)
tic()
rnorm(1000,0,1)
toc()

To save the elapsed time into a variable you can do:

install.packages("tictoc")
require(tictoc)
tic()
rnorm(1000,0,1)
exectime <- toc()
exectime <- exectime$toc - exectime$tic

Button Center CSS

I realize this is a very old question, but I stumbled across this problem today and I got it to work with

<div style="text-align:center;">
    <button>button1</button>
    <button>button2</button>
</div>

Cheers, Mark

How to unlock android phone through ADB

if the device is locked with black screen run the following:

  1. adb shell input keyevent 26 - this will turn screen on
  2. adb shell input keyevent 82 - this will unlock and ask for pin
  3. adb shell input text xxxx && adb shell input keyevent 66 - this will input your pin and press enter, unlocking device to home screen

How do I remove blank elements from an array?

another method:

> ["a","b","c","","","f","g"].keep_if{|some| some.present?}
=> ["a","b","c","f","g"]

how to set radio option checked onload with jQuery

If you want it to be truly dynamic and select the radio that corresponds to the incoming data, this works. It's using the gender value of the data passed in or uses default.

if(data['gender'] == ''){
 $('input:radio[name="gender"][value="Male"]').prop('checked', true);
}else{
  $('input:radio[name="gender"][value="' + data['gender'] +'"]').prop('checked', true);
};

Is it possible to use an input value attribute as a CSS selector?

It is possible, if you're using a browser which supports the CSS :valid pseudo-class and the pattern validation attribute on inputs -- which includes most modern browsers except IE9.

For instance, to change the text of an input from black to green when the correct answer is entered:

_x000D_
_x000D_
input {_x000D_
  color: black;_x000D_
}_x000D_
input:valid {_x000D_
  color: green;_x000D_
}
_x000D_
<p>Which country has fifty states?</p>_x000D_
_x000D_
<input type="text" pattern="^United States$">
_x000D_
_x000D_
_x000D_

How do I get the command-line for an Eclipse run configuration?

I found a solution on Stack Overflow for Java program run configurations which also works for JUnit run configurations.

You can get the full command executed by your configuration on the Debug tab, or more specifically the Debug view.

  1. Run your application
  2. Go to your Debug perspective
  3. There should be an entry in there (in the Debug View) for the app you've just executed
  4. Right-click the node which references java.exe or javaw.exe and select Properties In the dialog that pops up you'll see the Command Line which includes all jars, parameters, etc

remove objects from array by object property

findIndex works for modern browsers:

var myArr = [{id:'a'},{id:'myid'},{id:'c'}];
var index = myArr.findIndex(function(o){
  return o.id === 'myid';
})
if (index !== -1) myArr.splice(index, 1);

Getting all documents from one collection in Firestore

You could get the whole collection as an object, rather than array like this:

async getMarker() {
    const snapshot = await firebase.firestore().collection('events').get()
    const collection = {};
    snapshot.forEach(doc => {
        collection[doc.id] = doc.data();
    });
    return collection;
}

That would give you a better representation of what's in firestore. Nothing wrong with an array, just another option.

How do I download a file with Angular2 or greater

 let headers = new Headers({
                'Content-Type': 'application/json',
                'MyApp-Application': 'AppName',
                'Accept': 'application/vnd.ms-excel'
            });
            let options = new RequestOptions({
                headers: headers,
                responseType: ResponseContentType.Blob
            });


this.http.post(this.urlName + '/services/exportNewUpc', localStorageValue, options)
                .subscribe(data => {
                    if (navigator.appVersion.toString().indexOf('.NET') > 0)
                    window.navigator.msSaveBlob(data.blob(), "Export_NewUPC-Items_" + this.selectedcategory + "_" + this.retailname +"_Report_"+this.myDate+".xlsx");

                    else {
                        var a = document.createElement("a");
                        a.href = URL.createObjectURL(data.blob());
                        a.download = "Export_NewUPC-Items_" + this.selectedcategory + "_" + this.retailname +"_Report_"+this.myDate+ ".xlsx";
                        a.click();
                    }
                    this.ui_loader = false;
                    this.selectedexport = 0;
                }, error => {
                    console.log(error.json());
                    this.ui_loader = false;
                    document.getElementById("exceptionerror").click();
                });

Comparing two arrays of objects, and exclude the elements who match values into new array in JS

well, this using lodash or vanilla javascript it depends on the situation.

but for just return the array that contains the duplicates it can be achieved by the following, offcourse it was taken from @1983

var result = result1.filter(function (o1) {
    return result2.some(function (o2) {
        return o1.id === o2.id; // return the ones with equal id
   });
});
// if you want to be more clever...
let result = result1.filter(o1 => result2.some(o2 => o1.id === o2.id));

Can an AJAX response set a cookie?

According to the w3 spec section 4.6.3 for XMLHttpRequest a user agent should honor the Set-Cookie header. So the answer is yes you should be able to.

Quotation:

If the user agent supports HTTP State Management it should persist, discard and send cookies (as received in the Set-Cookie response header, and sent in the Cookie header) as applicable.

How to convert ActiveRecord results into an array of hashes

For current ActiveRecord (4.2.4+) there is a method to_hash on the Result object that returns an array of hashes. You can then map over it and convert to symbolized hashes:

# Get an array of hashes representing the result (column => value):
result.to_hash
# => [{"id" => 1, "title" => "title_1", "body" => "body_1"},
      {"id" => 2, "title" => "title_2", "body" => "body_2"},
      ...
     ]

result.to_hash.map(&:symbolize_keys)
# => [{:id => 1, :title => "title_1", :body => "body_1"},
      {:id => 2, :title => "title_2", :body => "body_2"},
      ...
     ]

See the ActiveRecord::Result docs for more info.