Programs & Examples On #New project

jQuery click event not working in mobile browsers

I had the same problem and fixed it by adding "mousedown touchstart"

$(document).on("mousedown touchstart", ".className", function() { // your code here });

inested of others

Django. Override save for model

Query the database for an existing record with the same PK. Compare the file sizes and checksums of the new and existing images to see if they're the same.

How to get all columns' names for all the tables in MySQL?

Piggybacking on Nicola's answer with some readable php

$a = mysqli_query($conn,"select * from information_schema.columns
where table_schema = 'your_db'
order by table_name,ordinal_position");
$b = mysqli_fetch_all($a,MYSQLI_ASSOC);
$d = array();
foreach($b as $c){
    if(!is_array($d[$c['TABLE_NAME']])){
        $d[$c['TABLE_NAME']] = array();
    }
    $d[$c['TABLE_NAME']][] = $c['COLUMN_NAME'];
}
echo "<pre>",print_r($d),"</pre>";

Collection was modified; enumeration operation may not execute in ArrayList

I like to iterate backward using a for loop, but this can get tedious compared to foreach. One solution I like is to create an enumerator that traverses the list backward. You can implement this as an extension method on ArrayList or List<T>. The implementation for ArrayList is below.

    public static IEnumerable GetRemoveSafeEnumerator(this ArrayList list)
    {
        for (int i = list.Count - 1; i >= 0; i--)
        {
            // Reset the value of i if it is invalid.
            // This occurs when more than one item
            // is removed from the list during the enumeration.
            if (i >= list.Count)
            {
                if (list.Count == 0)
                    yield break;

                i = list.Count - 1;
            }

            yield return list[i];
        }
    }

The implementation for List<T> is similar.

    public static IEnumerable<T> GetRemoveSafeEnumerator<T>(this List<T> list)
    {
        for (int i = list.Count - 1; i >= 0; i--)
        {
            // Reset the value of i if it is invalid.
            // This occurs when more than one item
            // is removed from the list during the enumeration.
            if (i >= list.Count)
            {
                if (list.Count == 0)
                    yield break;

                i = list.Count - 1;
            }

            yield return list[i];
        }
    }

The example below uses the enumerator to remove all even integers from an ArrayList.

    ArrayList list = new ArrayList() {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};

    foreach (int item in list.GetRemoveSafeEnumerator())
    {
        if (item % 2 == 0)
            list.Remove(item);
    }

Android: How to turn screen on and off programmatically?

As per Android API 28 and above you need to do the following to turn on the screen

setShowWhenLocked(true); 
setTurnScreenOn(true); 
KeyguardManager keyguardManager = (KeyguardManager)
getSystemService(Context.KEYGUARD_SERVICE);
keyguardManager.requestDismissKeyguard(this, null);

How can I override Bootstrap CSS styles?

If you are planning to make any rather big changes, it might be a good idea to make them directly in bootstrap itself and rebuild it. Then, you could reduce the amount of data loaded.

Please refer to Bootstrap on GitHub for the build guide.

AngularJS : Clear $watch

$watch returns a deregistration function. Calling it would deregister the $watcher.

var listener = $scope.$watch("quartz", function () {});
// ...
listener(); // Would clear the watch

How to resolve Error : Showing a modal dialog box or form when the application is not running in UserInteractive mode is not a valid operation

You can't show dialog box ON SERVER from ASP.NET application, well of course tehnically you can do that but it makes no sense since your user is using browser and it can't see messages raised on server. You have to understand how web sites work, server side code (ASP.NET in your case) produces html, javascript etc on server and then browser loads that content and displays it to the user, so in order to present modal message box to the user you have to use Javascript, for example alert function.

Here is the example for asp.net :

https://www.madskristensen.net/blog/javascript-alertshow(e2809dmessagee2809d)-from-aspnet-code-behind/

How do I connect to a SQL Server 2008 database using JDBC?

You can try configure SQL server:

  1. Step 1: Open SQL server 20xx Configuration Manager
  2. Step 2: Click Protocols for SQL.. in SQL server configuration. Then, right click TCP/IP, choose Properties
  3. Step 3: Click tab IP Address, Edit All TCP. Port is 1433

NOTE: ALL TCP port is 1433 Finally, restart the server.

Convert multidimensional array into single array

Following this pattern

$input = array(10, 20, array(30, 40), array('key1' => '50', 'key2'=>array(60), 70));

Call the function :

echo "<pre>";print_r(flatten_array($input, $output=null));

Function Declaration :

function flatten_array($input, $output=null) {
if($input == null) return null;
if($output == null) $output = array();
foreach($input as $value) {
    if(is_array($value)) {
        $output = flatten_array($value, $output);
    } else {
        array_push($output, $value);
    }
}
return $output;

}

How do you strip a character out of a column in SQL Server?

Take a look at the following function - REPLACE():

select replace(DataColumn, StringToReplace, NewStringValue)

//example to replace the s in test with the number 1
select replace('test', 's', '1')
//yields te1t

http://msdn.microsoft.com/en-us/library/ms186862.aspx

EDIT
If you want to remove a string, simple use the replace function with an empty string as the third parameter like:

select replace(DataColumn, 'StringToRemove', '')

How to read a single character at a time from a file in Python?

You should try f.read(1), which is definitely correct and the right thing to do.

Include of non-modular header inside framework module

I came across this issue as well and originally thought it was a CocoaPods issue, but it was an issue in the apps build settings where someone (probably me) had set ${PODS_ROOT} in Header Search Paths and set it to be a recursive search. This was allowing it to find headers that were not intended to be used when building the app. Once I set this to use non-recursive everything was fine. using recursive search is a terrible hack to try to find the proper headers. Lesson learned.

HTTP test server accepting GET/POST requests

nc one-liner local test server

Setup a local test server in one line under Linux:

nc -kdl localhost 8000

Sample request maker on another shell:

wget http://localhost:8000

then on the first shell you see the request that was made appear:

GET / HTTP/1.1
User-Agent: Wget/1.19.4 (linux-gnu)
Accept: */*
Accept-Encoding: identity
Host: localhost:8000
Connection: Keep-Alive

nc from the netcat-openbsd package is widely available and pre-installed on Ubuntu.

Tested on Ubuntu 18.04.

How can I delete all Git branches which have been merged?

I use a git-flow esque naming scheme, so this works very safely for me:

git branch --merged | grep -e "^\s\+\(fix\|feature\)/" | xargs git branch -d

It basically looks for merged commits that start with either string fix/ or feature/.

How to update column value in laravel

You may try this:

Page::where('id', $id)->update(array('image' => 'asdasd'));

There are other ways too but no need to use Page::find($id); in this case. But if you use find() then you may try it like this:

$page = Page::find($id);

// Make sure you've got the Page model
if($page) {
    $page->image = 'imagepath';
    $page->save();
}

Also you may use:

$page = Page::findOrFail($id);

So, it'll throw an exception if the model with that id was not found.

Skip over a value in the range function in python

In addition to the Python 2 approach here are the equivalents for Python 3:

# Create a range that does not contain 50
for i in [x for x in range(100) if x != 50]:
    print(i)

# Create 2 ranges [0,49] and [51, 100]
from itertools import chain
concatenated = chain(range(50), range(51, 100))
for i in concatenated:
    print(i)

# Create a iterator and skip 50
xr = iter(range(100))
for i in xr:
    print(i)
    if i == 49:
        next(xr)

# Simply continue in the loop if the number is 50
for i in range(100):
    if i == 50:
        continue
    print(i)

Ranges are lists in Python 2 and iterators in Python 3.

Creating a UICollectionView programmatically

colection view exam

    #import "CollectionViewController.h"
#import "BuyViewController.h"
#import "CollectionViewCell.h"

@interface CollectionViewController ()
{
    NSArray *mobiles;
    NSArray  *costumes;
    NSArray *shoes;
    NSInteger selectpath;
    NSArray *mobilerate;
    NSArray *costumerate;
    NSArray *shoerate;
}
@end

@implementation CollectionViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.title = self.receivename;
    mobiles = [[NSArray alloc]initWithObjects:@"7.jpg",@"6.jpg",@"5.jpg", nil];
    costumes = [[NSArray alloc]initWithObjects:@"shirt.jpg",@"costume2.jpg",@"costume1.jpg", nil];
    shoes = [[NSArray alloc]initWithObjects:@"shoe.jpg",@"shoe1.jpg",@"shoe2.jpg", nil];
    mobilerate = [[NSArray alloc]initWithObjects:@"10000",@"11000",@"13000",nil];
    costumerate = [[NSArray alloc]initWithObjects:@"699",@"999",@"899", nil];
    shoerate = [[NSArray alloc]initWithObjects:@"599",@"499",@"300", nil];
}
- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
}

-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
    return 1;
}
-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return 3;
}
-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *cellId = @"cell";
    UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:cellId forIndexPath:indexPath];

    UIImageView *collectionImg = (UIImageView *)[cell viewWithTag:100];

    if ([self.receivename isEqualToString:@"Mobiles"])
    {
        collectionImg.image = [UIImage imageNamed:[mobiles objectAtIndex:indexPath.row]];
    }
    else if ([self.receivename isEqualToString:@"Costumes"])
    {
        collectionImg.image = [UIImage imageNamed:[costumes objectAtIndex:indexPath.row]];
    }
    else
    {
        collectionImg.image = [UIImage imageNamed:[shoes objectAtIndex:indexPath.row]];
    }
    return cell;
}

-(void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath

{
    selectpath = indexPath.row;
    [self performSegueWithIdentifier:@"buynow" sender:self];
}

    // In a storyboard-based application, you will often want to do a little
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if ([segue.identifier isEqualToString:@"buynow"])
    {
        BuyViewController *obj = segue.destinationViewController;
        if ([self.receivename isEqualToString:@"Mobiles"])
        {
            obj.reciveimg = [mobiles objectAtIndex:selectpath];
            obj.labelrecive = [mobilerate objectAtIndex:selectpath];

        }
        else if ([self.receivename isEqualToString:@"Costumes"])
        {
            obj.reciveimg = [costumes objectAtIndex:selectpath];
            obj.labelrecive = [costumerate objectAtIndex:selectpath];
        }
        else
        {
            obj.reciveimg = [shoes objectAtIndex:selectpath];
            obj.labelrecive = [shoerate objectAtIndex:selectpath];
        }
        //     Get the new view controller using [segue destinationViewController].
        //     Pass the selected object to the new view controller.
    }
}

@end

.h file

@interface CollectionViewController :
UIViewController<UICollectionViewDelegate,UICollectionViewDataSource>
@property (strong, nonatomic) IBOutlet UICollectionView *collectionView;
@property (strong,nonatomic) NSString *receiveimg;
@property (strong,nonatomic) NSString *receivecostume;
@property (strong,nonatomic)NSString *receivename;

@end

Java - JPA - @Version annotation

Every time an entity is updated in the database the version field will be increased by one. Every operation that updates the entity in the database will have appended WHERE version = VERSION_THAT_WAS_LOADED_FROM_DATABASE to its query.

In checking affected rows of your operation the jpa framework can make sure there was no concurrent modification between loading and persisting your entity because the query would not find your entity in the database when it's version number has been increased between load and persist.

How to split a string with angularJS

You could try this:

$scope.testdata = [{ 'name': 'name,id' }, {'name':'someName,someId'}]
$scope.array= [];
angular.forEach($scope.testdata, function (value, key) {
    $scope.array.push({ 'name': value.name.split(',')[0], 'id': value.name.split(',')[1] });
});
console.log($scope.array)

This way you can save the data for later use and acces it by using an ng-repeat like this:

<div ng-repeat="item in array">{{item.name}}{{item.id}}</div>


I hope this helped someone,
Plunker link: here
All credits go to @jwpfox and @Mohideen ibn Mohammed from the answer above.

CreateProcess error=2, The system cannot find the file specified

The complete first argument of exec is being interpreted as the executable. Use

p = rt.exec(new String[] {"winrar.exe", "x", "h:\\myjar.jar", "*.*", "h:\\new" }
            null, 
            dir);

Why em instead of px?

It is wrong to say that one is a better choice than the other (or both wouldn't have been given their own purpose in the spec). It may even be worth noting that StackOverflow makes extensive use of px units. It is not the poor choice Spoike was told it was.

Definition of units

  • px is an absolute unit of measurement (like in, pt, or cm) that also happens to be 1/96 of an in unit (more on why later). Because it is an absolute measurement, it may be used any time you want to define something to be a particular size, rather than being proportional to something else like the size of the browser window or the font size.

    Like all the other absolute units, px units don't scale according to the width of the browser window. Thus, if your entire page design uses absolute units such as px rather than %, it won't adapt to the width of the browser. This is not inherently good or bad, just a choice that the designer needs to make between adhering to an exact size and being inflexible versus stretching but in the process not adhering to an exact size. It would be typical for a site to have a mix of fixed-size and flexible-sized objects.

    Fixed size elements often need to be incorporated into the page - such as advertising banners, logos or icons. This ensures you almost always need at least some px-based measurements in a design. Images, for example, will (by default) be scaled such that each pixel is 1*px* in size, so if you are designing around an image you'll need px units. It is also very useful for precise font sizing, and for border widths, where due to rounding it makes the most sense to use px units for the majority of screens.

    All absolute measurements are rigidly related to each other; that is, 1in is always 96px, just as 1in is always 72pt. (Note that 1in is almost never actually a physical inch when talking about screen-based media). All absolute measurements assume a nominal screen resolution of 96ppi and a nominal viewing distance of a desktop monitor, and on such a screen one px will be equal to one physical pixel on the screen and one in will be equal to 96 physical pixels. On screens that differ significantly in either pixel density or viewing distance, or if the user has zoomed the page using the browser's zoom function, px will no longer necessarily relate to physical pixels.

  • em is not an absolute unit - it is a unit that is relative to the currently chosen font size. Unless you have overridden font style by setting your font size with an absolute unit (such as px or pt), this will be affected by the choice of fonts in the user's browser or OS if they have made one, so it does not make sense to use em as a general unit of length except where you specifically want it to scale as the font size scales.

    Use em when you specifically want the size of something to depend on the current font size.

  • % is also a relative unit, in this case, relative to either the height or width of a parent element. They are a good alternative to px units for things like the total width of a design if your design does not rely on specific pixel sizes to set its size.

    Using % units in your design allows your design to adapt to the width of the screen/device, whereas using an absolute unit such as px does not.

How to show SVG file on React Native?

I use these two plugins,

  1. [react-native-svg] https://github.com/react-native-community/react-native-svg)
  2. [ react-native-svg-transformer] https://github.com/kristerkari/react-native-svg-transformer)

First off all, You need to install that plugin. After that you need to change your metro.config.js, with this code.

const { getDefaultConfig } = require("metro-config");

module.exports = (async () => {
  const {
    resolver: { sourceExts, assetExts }
  } = await getDefaultConfig();
  return {
    transformer: {
      babelTransformerPath: require.resolve("react-native-svg-transformer")
    },
    resolver: {
      assetExts: assetExts.filter(ext => ext !== "svg"),
      sourceExts: [...sourceExts, "svg"]
    }
  };
})();

For more details, you can visit this link

How to change the plot line color from blue to black?

If you get the object after creation (for instance after "seasonal_decompose"), you can always access and edit the properties of the plot; for instance, changing the color of the first subplot from blue to black:

plt.axes[0].get_lines()[0].set_color('black')

How do you change the value inside of a textfield flutter?

You can use the text editing controller to manipulate the value inside a textfield.

var textController = new TextEditingController();

Now, create a new textfield and set textController as the controller for the textfield as shown below.

 new TextField(controller: textController)

Now, create a RaisedButton anywhere in your code and set the desired text in the onPressed method of the RaisedButton.

new RaisedButton(
       onPressed: () {
          textController.text = "New text";
       }
    ),

I keep getting "Uncaught SyntaxError: Unexpected token o"

I had a similar problem just now and my solution might help. I'm using an iframe to upload and convert an xml file to json and send it back behind the scenes, and Chrome was adding some garbage to the incoming data that only would show up intermittently and cause the "Uncaught SyntaxError: Unexpected token o" error.

I was accessing the iframe data like this:

$('#load-file-iframe').contents().text()

which worked fine on localhost, but when I uploaded it to the server it stopped working only with some files and only when loading the files in a certain order. I don't really know what caused it, but this fixed it. I changed the line above to

$('#load-file-iframe').contents().find('body').text()

once I noticed some garbage in the HTML response.

Long story short check your raw HTML response data and you might turn something up.

CSS to set A4 paper size

https://github.com/cognitom/paper-css seems to solve all my needs.

Paper CSS for happy printing

Front-end printing solution - previewable and live-reloadable!

Slide up/down effect with ng-show and ng-animate

update for Angular 1.2+ (v1.2.6 at the time of this post):

.stuff-to-show {
  position: relative;
  height: 100px;
  -webkit-transition: top linear 1.5s;
  transition: top linear 1.5s;
  top: 0;
}
.stuff-to-show.ng-hide {
  top: -100px;
}
.stuff-to-show.ng-hide-add,
.stuff-to-show.ng-hide-remove {
  display: block!important;
}

(plunker)

Convert a String to a byte array and then back to the original String

import java.io.FileInputStream; import java.io.ByteArrayOutputStream;

public class FileHashStream { // write a new method that will provide a new Byte array, and where this generally reads from an input stream

public static byte[] read(InputStream is) throws Exception
{
    String path = /* type in the absolute path for the 'commons-codec-1.10-bin.zip' */;

    // must need a Byte buffer

    byte[] buf = new byte[1024 * 16]

    // we will use 16 kilobytes

    int len = 0;

    // we need a new input stream

    FileInputStream is = new FileInputStream(path);

    // use the buffer to update our "MessageDigest" instance

    while(true)
    {
        len = is.read(buf);
        if(len < 0) break;
        md.update(buf, 0, len);
    }

    // close the input stream

    is.close();

    // call the "digest" method for obtaining the final hash-result

    byte[] ret = md.digest();

    System.out.println("Length of Hash: " + ret.length);

    for(byte b : ret)
    {
        System.out.println(b + ", ");
    }

    String compare = "49276d206b696c6c696e6720796f757220627261696e206c696b65206120706f69736f6e6f7573206d757368726f6f6d";

    String verification = Hex.encodeHexString(ret);

    System.out.println();

    System.out.println("===")

    System.out.println(verification);

    System.out.println("Equals? " + verification.equals(compare));

}

}

Sqlite primary key on multiple columns

Since version 3.8.2 of SQLite, an alternative to explicit NOT NULL specifications is the "WITHOUT ROWID" specification: [1]

NOT NULL is enforced on every column of the PRIMARY KEY
in a WITHOUT ROWID table.

"WITHOUT ROWID" tables have potential efficiency advantages, so a less verbose alternative to consider is:

CREATE TABLE t (
  c1, 
  c2, 
  c3, 
  PRIMARY KEY (c1, c2)
 ) WITHOUT ROWID;

For example, at the sqlite3 prompt: sqlite> insert into t values(1,null,3); Error: NOT NULL constraint failed: t.c2

C: socket connection timeout

On Linux you can also use:

struct timeval timeout;
timeout.tv_sec  = 7;  // after 7 seconds connect() will timeout
timeout.tv_usec = 0;
setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &timeout, sizeof(timeout));
connect(...)

Don't forget to clear SO_SNDTIMEO after connect() if you don't need it.

Attach the Java Source Code

Normally, if you have installed the JDK6u14, eclipse should detect it and declare it automatically in its "installed JRE" list.

If not, you can add that JDK through "Windows/Preferences": Java > Installed JREs:

Just point to the root directory of your JDK installation: it should include the sources of the JDK (src.zip), automatically detected and attached to rt.jar by eclipse.

Add JRE VM, from pic.dhe.ibm.com/infocenter/iadthelp/v8r0/topic/org.eclipse.jdt.doc.user/tasks/images/task-add_jre_std_vm.PNG

Text blinking jQuery

Here you can find a jQuery blink plugin with its quick demo.

Basic blinking (unlimited blinking, blink period ~1 sec):

$('selector').blink();

On a more advanced usage, you can override any of the settings:

$('selector').blink({
    maxBlinks: 60, 
    blinkPeriod: 1000,   // in milliseconds
    onBlink: function(){}, 
    onMaxBlinks: function(){}
});

There you can specify the max number of blinks as well as have access to a couple of callbacks: onBlink and onMaxBlinks that are pretty self explanatory.

Works in IE 7 & 8, Chrome, Firefox, Safari and probably in IE 6 and Opera (although haven't tested on them).

(In full disclosure: I'm am the creator of this previous one. We had the legitimate need to use it at work [I know we all like to say this :-)] for an alarm within a system and I thought of sharing only for use on a legitimate need ;-)).

Here is another list of jQuery blink plugins.

Script parameters in Bash

Use the variables "$1", "$2", "$3" and so on to access arguments. To access all of them you can use "$@", or to get the count of arguments $# (might be useful to check for too few or too many arguments).

Text File Parsing with Python

From the accepted answer, it looks like your desired behaviour is to turn

skip 0
skip 1
skip 2
skip 3
"2012-06-23 03:09:13.23",4323584,-1.911224,-0.4657288,-0.1166382,-0.24823,0.256485,"NAN",-0.3489428,-0.130449,-0.2440527,-0.2942413,0.04944348,0.4337797,-1.105218,-1.201882,-0.5962594,-0.586636

into

2012,06,23,03,09,13.23,4323584,-1.911224,-0.4657288,-0.1166382,-0.24823,0.256485,NAN,-0.3489428,-0.130449,-0.2440527,-0.2942413,0.04944348,0.4337797,-1.105218,-1.201882,-0.5962594,-0.586636

If that's right, then I think something like

import csv

with open("test.dat", "rb") as infile, open("test.csv", "wb") as outfile:
    reader = csv.reader(infile)
    writer = csv.writer(outfile, quoting=False)
    for i, line in enumerate(reader):
        if i < 4: continue
        date = line[0].split()
        day = date[0].split('-')
        time = date[1].split(':')
        newline = day + time + line[1:]
        writer.writerow(newline)

would be a little simpler than the reps stuff.

How to set opacity to the background color of a div?

I think this covers just about all of the browsers. I have used it successfully in the past.

#div {
    filter: alpha(opacity=50); /* internet explorer */
    -khtml-opacity: 0.5;      /* khtml, old safari */
    -moz-opacity: 0.5;       /* mozilla, netscape */
    opacity: 0.5;           /* fx, safari, opera */
}

convert string date to java.sql.Date

This works for me without throwing an exception:

package com.sandbox;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class Sandbox {

    public static void main(String[] args) throws ParseException {
        SimpleDateFormat format = new SimpleDateFormat("yyyyMMdd");
        Date parsed = format.parse("20110210");
        java.sql.Date sql = new java.sql.Date(parsed.getTime());
    }


}

Spring: return @ResponseBody "ResponseEntity<List<JSONObject>>"

Now I return Object. I don't know better solution, but it works.

@RequestMapping(value="", method=RequestMethod.GET, produces=MediaType.APPLICATION_JSON_VALUE)
public @ResponseBody ResponseEntity<Object> getAll() {
    List<Entity> entityList = entityManager.findAll();

    List<JSONObject> entities = new ArrayList<JSONObject>();
    for (Entity n : entityList) {
        JSONObject Entity = new JSONObject();
        entity.put("id", n.getId());
        entity.put("address", n.getAddress());
        entities.add(entity);
    }
    return new ResponseEntity<Object>(entities, HttpStatus.OK);
}

Streaming Audio from A URL in Android using MediaPlayer?

Use

 mediaplayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
 mediaplayer.prepareAsync();
 mediaplayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
      @Override
      public void onPrepared(MediaPlayer mp) {
          mediaplayer.start();
      }
 });

How to set a variable inside a loop for /F

Try this:

setlocal EnableDelayedExpansion

...

for /F "tokens=*" %%a in ('type %FileName%') do (
    set z=%%a
    echo !z!
    echo %%a
)

How can I iterate through a string and also know the index (current position)?

Like this:


    std::string s("Test string");
    std::string::iterator it = s.begin();

    //Use the iterator...
    ++it;
    //...

    std::cout << "index is: " << std::distance(s.begin(), it) << std::endl;

Using PropertyInfo.GetValue()

In your example propertyInfo.GetValue(this, null) should work. Consider altering GetNamesAndTypesAndValues() as follows:

public void GetNamesAndTypesAndValues()
{
  foreach (PropertyInfo propertyInfo in allClassProperties)
  {
    Console.WriteLine("{0} [type = {1}] [value = {2}]",
      propertyInfo.Name,
      propertyInfo.PropertyType,
      propertyInfo.GetValue(this, null));
  }
}

Cannot find Dumpbin.exe

Instead of using the dumpin.exe it is possible to call the link.exe with several options:

Example: link /dump /all myfile.lib

For detailed options see output of link /dump

In case of Visual Studio C++ Express installation, the link.exe is located here:

{root}\Program Files (x86)\Microsoft Visual Studio 10.0\VC\bin\

The best way is to open the "Visual Studio Command Prompt" and then enter the lines above.

Eclipse: How do you change the highlight color of the currently selected method/expression?

For those working in Titanium Studio, the item is a little different: It's under the "Titanium Studio" Themes tab.

The color to change is the "Selection" one in the top right.

enter image description here

Can a CSV file have a comment?

If you need something like:

  ¦ A                              ¦ B
--+--------------------------------+---
1 ¦ #My comment, something else    ¦
2 ¦ 1                              ¦ 2

Your CSV may contain the following lines:

"#My comment, something else"
1,2

Pay close attention at the 'quotes' in the first line.

When converting your text to columns using the Excel wizard, remember checking the 'Treat consecutive delimiters as one', setting it to use 'quotes' as delimiter.

Thus, Excel will split the text at the commas, keeping the 'comment' line as a single column value (and it will remove the quotes).

SQL Server check case-sensitivity?

SQL Server is not case sensitive. SELECT * FROM SomeTable is the same as SeLeCT * frOM soMetaBLe.

How to shrink/purge ibdata1 file in MySQL

If you use the InnoDB storage engine for (some of) your MySQL tables, you’ve probably already came across a problem with its default configuration. As you may have noticed in your MySQL’s data directory (in Debian/Ubuntu – /var/lib/mysql) lies a file called ‘ibdata1'. It holds almost all the InnoDB data (it’s not a transaction log) of the MySQL instance and could get quite big. By default this file has a initial size of 10Mb and it automatically extends. Unfortunately, by design InnoDB data files cannot be shrinked. That’s why DELETEs, TRUNCATEs, DROPs, etc. will not reclaim the space used by the file.

I think you can find good explanation and solution there :

http://vdachev.net/2007/02/22/mysql-reducing-ibdata1/

In Chart.js set chart title, name of x axis and y axis?

In Chart.js version 2.0, it is possible to set labels for axes:

options = {
  scales: {
    yAxes: [{
      scaleLabel: {
        display: true,
        labelString: 'probability'
      }
    }]
  }     
}

See Labelling documentation for more details.

set environment variable in python script

There are many good answers here but you should avoid at all cost to pass untrusted variables to subprocess using shell=True as this is a security risk. The variables can escape to the shell and run arbitrary commands! If you just can't avoid it at least use python3's shlex.quote() to escape the string (if you have multiple space-separated arguments, quote each split instead of the full string).

shell=False is always the default where you pass an argument array.

Now the safe solutions...

Method #1

Change your own process's environment - the new environment will apply to python itself and all subprocesses.

os.environ['LD_LIBRARY_PATH'] = 'my_path'
command = ['sqsub', '-np', var1, '/homedir/anotherdir/executable']
subprocess.check_call(command)

Method #2

Make a copy of the environment and pass is to the childen. You have total control over the children environment and won't affect python's own environment.

myenv = os.environ.copy()
myenv['LD_LIBRARY_PATH'] = 'my_path'
command = ['sqsub', '-np', var1, '/homedir/anotherdir/executable']
subprocess.check_call(command, env=myenv)

Method #3

Unix only: Execute env to set the environment variable. More cumbersome if you have many variables to modify and not portabe, but like #2 you retain full control over python and children environments.

command = ['env', 'LD_LIBRARY_PATH=my_path', 'sqsub', '-np', var1, '/homedir/anotherdir/executable']
subprocess.check_call(command)

Of course if var1 contain multiple space-separated argument they will now be passed as a single argument with spaces. To retain original behavior with shell=True you must compose a command array that contain the splitted string:

command = ['sqsub', '-np'] + var1.split() + ['/homedir/anotherdir/executable']

/bin/sh: apt-get: not found

The image you're using is Alpine based, so you can't use apt-get because it's Ubuntu's package manager.

To fix this just use:

apk update and apk add

Asp.Net WebApi2 Enable CORS not working with AspNet.WebApi.Cors 5.2.3

You just need to change some files. This works for me.

Global.ascx

public class WebApiApplication : System.Web.HttpApplication {
    protected void Application_Start()
    {
        WebApiConfig.Register(GlobalConfiguration.Configuration);
    } }

WebApiConfig.cs

All the requests has to call this code.

public static class WebApiConfig {
    public static void Register(HttpConfiguration config)
    {
        EnableCrossSiteRequests(config);
        AddRoutes(config);
    }

    private static void AddRoutes(HttpConfiguration config)
    {
        config.Routes.MapHttpRoute(
            name: "Default",
            routeTemplate: "api/{controller}/"
        );
    }

    private static void EnableCrossSiteRequests(HttpConfiguration config)
    {
        var cors = new EnableCorsAttribute(
            origins: "*", 
            headers: "*", 
            methods: "*");
        config.EnableCors(cors);
    } }

Some Controller

Nothing to change.

Web.config

You need to add handlers in your web.config

<configuration> 
  <system.webServer>
    <handlers>
      <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
      <remove name="OPTIONSVerbHandler" />
      <remove name="TRACEVerbHandler" />
      <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
    </handlers>   
  </system.webServer> 
</configuration>

How do you create a yes/no boolean field in SQL server?

bit will be the simplest and also takes up the least space. Not very verbose compared to "Y/N" but I am fine with it.

jQuery event to trigger action when a div is made visible

Use jQuery Waypoints :

$('#contentDiv').waypoint(function() {
   alert('do something');
});

Other examples on the site of jQuery Waypoints.

Checking for the correct number of arguments

cat script.sh

    var1=$1
    var2=$2
    if [ "$#" -eq 2 ]
    then
            if [ -d $var1 ]
            then
            echo directory ${var1} exist
            else
            echo Directory ${var1} Does not exists
            fi
            if [ -d $var2 ]
            then
            echo directory ${var2} exist
            else
            echo Directory ${var2} Does not exists
            fi
    else
    echo "Arguments are not equals to 2"
    exit 1
    fi

execute it like below -

./script.sh directory1 directory2

Output will be like -

directory1 exit
directory2 Does not exists

Test if characters are in a string

Use this function from stringi package:

> stri_detect_fixed("test",c("et","es"))
[1] FALSE  TRUE

Some benchmarks:

library(stringi)
set.seed(123L)
value <- stri_rand_strings(10000, ceiling(runif(10000, 1, 100))) # 10000 random ASCII strings
head(value)

chars <- "es"
library(microbenchmark)
microbenchmark(
   grepl(chars, value),
   grepl(chars, value, fixed=TRUE),
   grepl(chars, value, perl=TRUE),
   stri_detect_fixed(value, chars),
   stri_detect_regex(value, chars)
)
## Unit: milliseconds
##                               expr       min        lq    median        uq       max neval
##                grepl(chars, value) 13.682876 13.943184 14.057991 14.295423 15.443530   100
##  grepl(chars, value, fixed = TRUE)  5.071617  5.110779  5.281498  5.523421 45.243791   100
##   grepl(chars, value, perl = TRUE)  1.835558  1.873280  1.956974  2.259203  3.506741   100
##    stri_detect_fixed(value, chars)  1.191403  1.233287  1.309720  1.510677  2.821284   100
##    stri_detect_regex(value, chars)  6.043537  6.154198  6.273506  6.447714  7.884380   100

How do I set proxy for chrome in python webdriver?

For people out there asking how to setup proxy server in chrome which needs authentication should follow these steps.

  1. Create a proxy.py file in your project, use this code and call proxy_chrome from
    proxy.py everytime you need it. You need to pass parameters like proxy server, port and username password for authentication.

How to do paging in AngularJS?

I would like to add my solution that works with ngRepeat and filters that you use with it without using a $watch or a sliced array.

Your filter results will be paginated!

var app = angular.module('app', ['ui.bootstrap']);

app.controller('myController', ['$scope', function($scope){
    $scope.list= ['a', 'b', 'c', 'd', 'e'];

    $scope.pagination = {
        currentPage: 1,
        numPerPage: 5,
        totalItems: 0
    };

    $scope.searchFilter = function(item) {
        //Your filter results will be paginated!
        //The pagination will work even with other filters involved
        //The total number of items in the result of your filter is accounted for
    };

    $scope.paginationFilter = function(item, index) {
        //Every time the filter is used it restarts the totalItems
        if(index === 0) 
            $scope.pagination.totalItems = 0;

        //This holds the totalItems after the filters are applied
        $scope.pagination.totalItems++;

        if(
            index >= (($scope.pagination.currentPage - 1) * $scope.pagination.numPerPage)
            && index < ((($scope.pagination.currentPage - 1) * $scope.pagination.numPerPage) + $scope.pagination.numPerPage)
        )
            return true; //return true if item index is on the currentPage

        return false;
    };
}]);

In the HTML make sure that you apply your filters to the ngRepeat before the pagination filter.

<table data-ng-controller="myController">
    <tr data-ng-repeat="item in list | filter: searchFilter | filter: paginationFilter track by $index">
        <td>
            {{item}}
        </td>
    <tr>
</table>
<ul class="pagination-sm"
    uib-pagination
    data-boundary-links="true"
    data-total-items="pagination.totalItems"
    data-items-per-page="pagination.numPerPage"
    data-ng-model="pagination.currentPage"
    data-previous-text="&lsaquo;"
    data-next-text="&rsaquo;"
    data-first-text="&laquo;"
    data-last-text="&raquo;">
 </ul>

Check if element exists in jQuery

You can also use array-like notation and check for the first element. The first element of an empty array or collection is simply undefined, so you get the "normal" javascript truthy/falsy behaviour:

var el = $('body')[0];
if (el) {
    console.log('element found', el);
}
if (!el) {
    console.log('no element found');
}

Bootstrap 3 navbar active li not changing background-color

Did you include "bootstrap-theme.css" files on your code?

In "bootstrap-theme.min.css" files, background-image about ".active" is existed for "navbar" (check this screenshot: http://i.imgur.com/1etLIyY.png).

It will re-declare your style code, and then it will be effected on your code.

So after you delete or re-declare them (background-image), you can use your background color style about the ".active" tag.

How to loop over directories in Linux?

The technique I use most often is find | xargs. For example, if you want to make every file in this directory and all of its subdirectories world-readable, you can do:

find . -type f -print0 | xargs -0 chmod go+r
find . -type d -print0 | xargs -0 chmod go+rx

The -print0 option terminates with a NULL character instead of a space. The -0 option splits its input the same way. So this is the combination to use on files with spaces.

You can picture this chain of commands as taking every line output by find and sticking it on the end of a chmod command.

If the command you want to run as its argument in the middle instead of on the end, you have to be a bit creative. For instance, I needed to change into every subdirectory and run the command latemk -c. So I used (from Wikipedia):

find . -type d -depth 1 -print0 | \
    xargs -0 sh -c 'for dir; do pushd "$dir" && latexmk -c && popd; done' fnord

This has the effect of for dir $(subdirs); do stuff; done, but is safe for directories with spaces in their names. Also, the separate calls to stuff are made in the same shell, which is why in my command we have to return back to the current directory with popd.

How to comment lines in rails html.erb files?

This is CLEANEST, SIMPLEST ANSWER for CONTIGUOUS NON-PRINTING Ruby Code:

The below also happens to answer the Original Poster's question without, the "ugly" conditional code that some commenters have mentioned.


  1. CONTIGUOUS NON-PRINTING Ruby Code

    • This will work in any mixed language Rails View file, e.g, *.html.erb, *.js.erb, *.rhtml, etc.

    • This should also work with STD OUT/printing code, e.g. <%#= f.label :title %>

    • DETAILS:

      Rather than use rails brackets on each line and commenting in front of each starting bracket as we usually do like this:

        <%# if flash[:myErrors] %>
          <%# if flash[:myErrors].any? %>
            <%# if @post.id.nil? %>
              <%# if @myPost!=-1 %>
                <%# @post = @myPost %>
              <%# else %>
                <%# @post = Post.new %>
              <%# end %>
            <%# end %>
          <%# end %>
        <%# end %>
      

      YOU CAN INSTEAD add only one comment (hashmark/poundsign) to the first open Rails bracket if you write your code as one large block... LIKE THIS:

        <%# 
          if flash[:myErrors] then
            if flash[:myErrors].any? then
              if @post.id.nil? then
                if @myPost!=-1 then
                  @post = @myPost 
                else 
                  @post = Post.new 
                end 
              end 
            end 
          end 
        %>
      

How to make multiple divs display in one line but still retain width?

You can float your column divs using float: left; and give them widths.

And to make sure none of your other content gets messed up, you can wrap the floated divs within a parent div and give it some clear float styling.

Hope this helps.

How to Lock the data in a cell in excel using vba

You can also do it on the worksheet level captured in the worksheet's change event. If that suites your needs better. Allows for dynamic locking based on values, criteria, ect...

Private Sub Worksheet_Change(ByVal Target As Range)

    'set your criteria here
    If Target.Column = 1 Then

        'must disable events if you change the sheet as it will
        'continually trigger the change event
        Application.EnableEvents = False
        Application.Undo
        Application.EnableEvents = True

        MsgBox "You cannot do that!"
    End If
End Sub

Explanation of the UML arrows

enter image description here

enter image description here

I think these pictures are understandable.

Calling onclick on a radiobutton list using javascript

_x000D_
_x000D_
Hi, I think all of the above might work. In case what you need is simple, I used:_x000D_
_x000D_
<body>_x000D_
    <div class="radio-buttons-choice" id="container-3-radio-buttons-choice">_x000D_
        <input type="radio" name="one" id="one-variable-equations" onclick="checkRadio(name)"><label>Only one</label><br>_x000D_
        <input type="radio" name="multiple" id="multiple-variable-equations" onclick="checkRadio(name)"><label>I have multiple</label>_x000D_
    </div>_x000D_
_x000D_
<script>_x000D_
function checkRadio(name) {_x000D_
    if(name == "one"){_x000D_
    console.log("Choice: ", name);_x000D_
        document.getElementById("one-variable-equations").checked = true;_x000D_
        document.getElementById("multiple-variable-equations").checked = false;_x000D_
_x000D_
    } else if (name == "multiple"){_x000D_
        console.log("Choice: ", name);_x000D_
        document.getElementById("multiple-variable-equations").checked = true;_x000D_
        document.getElementById("one-variable-equations").checked = false;_x000D_
    }_x000D_
}_x000D_
</script>_x000D_
</body>
_x000D_
_x000D_
_x000D_

What is the Git equivalent for revision number?

I wrote some PowerShell utilities for retrieving version information from Git and simplifying tagging

functions: Get-LastVersion, Get-Revision, Get-NextMajorVersion, Get-NextMinorVersion, TagNextMajorVersion, TagNextMinorVersion:

# Returns the last version by analysing existing tags,
# assumes an initial tag is present, and
# assumes tags are named v{major}.{minor}.[{revision}]
#
function Get-LastVersion(){
  $lastTagCommit = git rev-list --tags --max-count=1
  $lastTag = git describe --tags $lastTagCommit
  $tagPrefix = "v"
  $versionString = $lastTag -replace "$tagPrefix", ""
  Write-Host -NoNewline "last tagged commit "
  Write-Host -NoNewline -ForegroundColor "yellow" $lastTag
  Write-Host -NoNewline " revision "
  Write-Host -ForegroundColor "yellow" "$lastTagCommit"
  [reflection.assembly]::LoadWithPartialName("System.Version")

  $version = New-Object System.Version($versionString)
  return $version;
}

# Returns current revision by counting the number of commits to HEAD
function Get-Revision(){
   $lastTagCommit = git rev-list HEAD
   $revs  = git rev-list $lastTagCommit |  Measure-Object -Line
   return $revs.Lines
}

# Returns the next major version {major}.{minor}.{revision}
function Get-NextMajorVersion(){
    $version = Get-LastVersion;
    [reflection.assembly]::LoadWithPartialName("System.Version")
    [int] $major = $version.Major+1;
    $rev = Get-Revision
    $nextMajor = New-Object System.Version($major, 0, $rev);
    return $nextMajor;
}

# Returns the next minor version {major}.{minor}.{revision}
function Get-NextMinorVersion(){
    $version = Get-LastVersion;
    [reflection.assembly]::LoadWithPartialName("System.Version")
    [int] $minor = $version.Minor+1;
    $rev = Get-Revision
    $next = New-Object System.Version($version.Major, $minor, $rev);
    return $next;
}

# Creates a tag with the next minor version
function TagNextMinorVersion($tagMessage){
    $version = Get-NextMinorVersion;
    $tagName = "v{0}" -f "$version".Trim();
    Write-Host -NoNewline "Tagging next minor version to ";
    Write-Host -ForegroundColor DarkYellow "$tagName";
    git tag -a $tagName -m $tagMessage
}

# Creates a tag with the next major version (minor version starts again at 0)
function TagNextMajorVersion($tagMessage){
    $version = Get-NextMajorVersion;
    $tagName = "v{0}" -f "$version".Trim();
    Write-Host -NoNewline "Tagging next majo version to ";
    Write-Host -ForegroundColor DarkYellow "$tagName";
    git tag -a $tagName -m $tagMessage
}

RegEx to make sure that the string contains at least one lower case char, upper case char, digit and symbol

You can match those three groups separately, and make sure that they all present. Also, [^\w] seems a bit too broad, but if that's what you want you might want to replace it with \W.

Delete default value of an input text on click

<input name="Email" type="text" id="Email" placeholder="enter your question" />

The placeholder attribute specifies a short hint that describes the expected value of an input field (e.g. a sample value or a short description of the expected format).

The short hint is displayed in the input field before the user enters a value.

Note: The placeholder attribute works with the following input types: text, search, url, tel, email, and password.

I think this will help.

Remove CSS from a Div using JQuery

You could use the removeAttr method, if you want to delete all the inline style you added manually with javascript. It's better to use CSS classes but you never know.

$("#displayPanel div").removeAttr("style")

Find out a Git branch creator

git for-each-ref --format='%(authorname) %09 -%(refname)' | sort

How Do I Replace/Change The Heading Text Inside <h3></h3>, Using jquery?

jQuery(document).ready(function(){
   jQuery(".head h3").html('Public Offers');
});

Delete statement in SQL is very slow

Check execution plan of this delete statement. Have a look if index seek is used. Also what is data type of col?

If you are using wrong data type, change update statement (like from '1' to 1 or N'1').

If index scan is used consider using some query hint..

Format y axis as percent

I propose an alternative method using seaborn

Working code:

import pandas as pd
import seaborn as sns
data=np.random.rand(10,2)*100
df = pd.DataFrame(data, columns=['A', 'B'])
ax= sns.lineplot(data=df, markers= True)
ax.set(xlabel='xlabel', ylabel='ylabel', title='title')
#changing ylables ticks
y_value=['{:,.2f}'.format(x) + '%' for x in ax.get_yticks()]
ax.set_yticklabels(y_value)

enter image description here

Cannot ping AWS EC2 instance

A few years late but hopefully this will help someone else...

1) First make sure the EC2 instance has a public IP. If has a Public DNS or Public IP address (circled below) then you should be good. This will be the address you ping. AWS public DNS address

2) Next make sure the Amazon network rules allow Echo Requests. Go to the Security Group for the EC2.

  • right click, select inbound rules
  • A: select Add Rule
  • B: Select Custom ICMP Rule - IPv4
  • C: Select Echo Request
  • D: Select either Anywhere or My IP
  • E: Select Save

Add a Security Group ICMP Rule to allow Pings and Echos

3) Next, Windows firewall blocks inbound Echo requests by default. Allow Echo requests by creating a windows firewall exception...

  • Go to Start and type Windows Firewall with Advanced Security
  • Select inbound rules

Add a Windows Server ICMP Rule to allow Pings and Echos

4) Done! Hopefully you should now be able to ping your server.

How can I mimic the bottom sheet from the Maps app?

I released a library based on my answer below.

It mimics the Shortcuts application overlay. See this article for details.

The main component of the library is the OverlayContainerViewController. It defines an area where a view controller can be dragged up and down, hiding or revealing the content underneath it.

let contentController = MapsViewController()
let overlayController = SearchViewController()

let containerController = OverlayContainerViewController()
containerController.delegate = self
containerController.viewControllers = [
    contentController,
    overlayController
]

window?.rootViewController = containerController

Implement OverlayContainerViewControllerDelegate to specify the number of notches wished:

enum OverlayNotch: Int, CaseIterable {
    case minimum, medium, maximum
}

func numberOfNotches(in containerViewController: OverlayContainerViewController) -> Int {
    return OverlayNotch.allCases.count
}

func overlayContainerViewController(_ containerViewController: OverlayContainerViewController,
                                    heightForNotchAt index: Int,
                                    availableSpace: CGFloat) -> CGFloat {
    switch OverlayNotch.allCases[index] {
        case .maximum:
            return availableSpace * 3 / 4
        case .medium:
            return availableSpace / 2
        case .minimum:
            return availableSpace * 1 / 4
    }
}

SwiftUI (12/29/20)

A SwiftUI version of the library is now available.

Color.red.dynamicOverlay(Color.green)

Previous answer

I think there is a significant point that is not treated in the suggested solutions: the transition between the scroll and the translation.

Maps transition between the scroll and the translation

In Maps, as you may have noticed, when the tableView reaches contentOffset.y == 0, the bottom sheet either slides up or goes down.

The point is tricky because we can not simply enable/disable the scroll when our pan gesture begins the translation. It would stop the scroll until a new touch begins. This is the case in most of the proposed solutions here.

Here is my try to implement this motion.

Starting point: Maps App

To start our investigation, let's visualize the view hierarchy of Maps (start Maps on a simulator and select Debug > Attach to process by PID or Name > Maps in Xcode 9).

Maps debug view hierarchy

It doesn't tell how the motion works, but it helped me to understand the logic of it. You can play with the lldb and the view hierarchy debugger.

Our view controller stacks

Let's create a basic version of the Maps ViewController architecture.

We start with a BackgroundViewController (our map view):

class BackgroundViewController: UIViewController {
    override func loadView() {
        view = MKMapView()
    }
}

We put the tableView in a dedicated UIViewController:

class OverlayViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {

    lazy var tableView = UITableView()

    override func loadView() {
        view = tableView
        tableView.dataSource = self
        tableView.delegate = self
    }

    [...]
}

Now, we need a VC to embed the overlay and manage its translation. To simplify the problem, we consider that it can translate the overlay from one static point OverlayPosition.maximum to another OverlayPosition.minimum.

For now it only has one public method to animate the position change and it has a transparent view:

enum OverlayPosition {
    case maximum, minimum
}

class OverlayContainerViewController: UIViewController {

    let overlayViewController: OverlayViewController
    var translatedViewHeightContraint = ...

    override func loadView() {
        view = UIView()
    }

    func moveOverlay(to position: OverlayPosition) {
        [...]
    }
}

Finally we need a ViewController to embed the all:

class StackViewController: UIViewController {

    private var viewControllers: [UIViewController]

    override func viewDidLoad() {
        super.viewDidLoad()
        viewControllers.forEach { gz_addChild($0, in: view) }
    }
}

In our AppDelegate, our startup sequence looks like:

let overlay = OverlayViewController()
let containerViewController = OverlayContainerViewController(overlayViewController: overlay)
let backgroundViewController = BackgroundViewController()
window?.rootViewController = StackViewController(viewControllers: [backgroundViewController, containerViewController])

The difficulty behind the overlay translation

Now, how to translate our overlay?

Most of the proposed solutions use a dedicated pan gesture recognizer, but we actually already have one : the pan gesture of the table view. Moreover, we need to keep the scroll and the translation synchronised and the UIScrollViewDelegate has all the events we need!

A naive implementation would use a second pan Gesture and try to reset the contentOffset of the table view when the translation occurs:

func panGestureAction(_ recognizer: UIPanGestureRecognizer) {
    if isTranslating {
        tableView.contentOffset = .zero
    }
}

But it does not work. The tableView updates its contentOffset when its own pan gesture recognizer action triggers or when its displayLink callback is called. There is no chance that our recognizer triggers right after those to successfully override the contentOffset. Our only chance is either to take part of the layout phase (by overriding layoutSubviews of the scroll view calls at each frame of the scroll view) or to respond to the didScroll method of the delegate called each time the contentOffset is modified. Let's try this one.

The translation Implementation

We add a delegate to our OverlayVC to dispatch the scrollview's events to our translation handler, the OverlayContainerViewController :

protocol OverlayViewControllerDelegate: class {
    func scrollViewDidScroll(_ scrollView: UIScrollView)
    func scrollViewDidStopScrolling(_ scrollView: UIScrollView)
}

class OverlayViewController: UIViewController {

    [...]

    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        delegate?.scrollViewDidScroll(scrollView)
    }

    func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) {
        delegate?.scrollViewDidStopScrolling(scrollView)
    }
}

In our container, we keep track of the translation using a enum:

enum OverlayInFlightPosition {
    case minimum
    case maximum
    case progressing
}

The current position calculation looks like :

private var overlayInFlightPosition: OverlayInFlightPosition {
    let height = translatedViewHeightContraint.constant
    if height == maximumHeight {
        return .maximum
    } else if height == minimumHeight {
        return .minimum
    } else {
        return .progressing
    }
}

We need 3 methods to handle the translation:

The first one tells us if we need to start the translation.

private func shouldTranslateView(following scrollView: UIScrollView) -> Bool {
    guard scrollView.isTracking else { return false }
    let offset = scrollView.contentOffset.y
    switch overlayInFlightPosition {
    case .maximum:
        return offset < 0
    case .minimum:
        return offset > 0
    case .progressing:
        return true
    }
}

The second one performs the translation. It uses the translation(in:) method of the scrollView's pan gesture.

private func translateView(following scrollView: UIScrollView) {
    scrollView.contentOffset = .zero
    let translation = translatedViewTargetHeight - scrollView.panGestureRecognizer.translation(in: view).y
    translatedViewHeightContraint.constant = max(
        Constant.minimumHeight,
        min(translation, Constant.maximumHeight)
    )
}

The third one animates the end of the translation when the user releases its finger. We calculate the position using the velocity & the current position of the view.

private func animateTranslationEnd() {
    let position: OverlayPosition =  // ... calculation based on the current overlay position & velocity
    moveOverlay(to: position)
}

Our overlay's delegate implementation simply looks like :

class OverlayContainerViewController: UIViewController {

    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        guard shouldTranslateView(following: scrollView) else { return }
        translateView(following: scrollView)
    }

    func scrollViewDidStopScrolling(_ scrollView: UIScrollView) {
        // prevent scroll animation when the translation animation ends
        scrollView.isEnabled = false
        scrollView.isEnabled = true
        animateTranslationEnd()
    }
}

Final problem: dispatching the overlay container's touches

The translation is now pretty efficient. But there is still a final problem: the touches are not delivered to our background view. They are all intercepted by the overlay container's view. We can not set isUserInteractionEnabled to false because it would also disable the interaction in our table view. The solution is the one used massively in the Maps app, PassThroughView:

class PassThroughView: UIView {
    override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
        let view = super.hitTest(point, with: event)
        if view == self {
            return nil
        }
        return view
    }
}

It removes itself from the responder chain.

In OverlayContainerViewController:

override func loadView() {
    view = PassThroughView()
}

Result

Here is the result:

Result

You can find the code here.

Please if you see any bugs, let me know ! Note that your implementation can of course use a second pan gesture, specially if you add a header in your overlay.

Update 23/08/18

We can replace scrollViewDidEndDragging with willEndScrollingWithVelocity rather than enabling/disabling the scroll when the user ends dragging:

func scrollView(_ scrollView: UIScrollView,
                willEndScrollingWithVelocity velocity: CGPoint,
                targetContentOffset: UnsafeMutablePointer<CGPoint>) {
    switch overlayInFlightPosition {
    case .maximum:
        break
    case .minimum, .progressing:
        targetContentOffset.pointee = .zero
    }
    animateTranslationEnd(following: scrollView)
}

We can use a spring animation and allow user interaction while animating to make the motion flow better:

func moveOverlay(to position: OverlayPosition,
                 duration: TimeInterval,
                 velocity: CGPoint) {
    overlayPosition = position
    translatedViewHeightContraint.constant = translatedViewTargetHeight
    UIView.animate(
        withDuration: duration,
        delay: 0,
        usingSpringWithDamping: velocity.y == 0 ? 1 : 0.6,
        initialSpringVelocity: abs(velocity.y),
        options: [.allowUserInteraction],
        animations: {
            self.view.layoutIfNeeded()
    }, completion: nil)
}

Center an item with position: relative

You can use calc to position element relative to center. For example if you want to position element 200px right from the center .. you can do this :

#your_element{
    position:absolute;
    left: calc(50% + 200px);
}

Dont forget this

When you use signs + and - you must have one blank space between sign and number, but when you use signs * and / there is no need for blank space.

How do you convert between 12 hour time and 24 hour time in PHP?

// 24-hour time to 12-hour time 
$time_in_12_hour_format  = date("g:i a", strtotime("13:30"));

// 12-hour time to 24-hour time 
$time_in_24_hour_format  = date("H:i", strtotime("1:30 PM"));

Encrypt and decrypt a String in java

Whether encrypted be the same when plain text is encrypted with the same key depends of algorithm and protocol. In cryptography there is initialization vector IV: http://en.wikipedia.org/wiki/Initialization_vector that used with various ciphers makes that the same plain text encrypted with the same key gives various cipher texts.

I advice you to read more about cryptography on Wikipedia, Bruce Schneier http://www.schneier.com/books.html and "Beginning Cryptography with Java" by David Hook. The last book is full of examples of usage of http://www.bouncycastle.org library.

If you are interested in cryptography the there is CrypTool: http://www.cryptool.org/ CrypTool is a free, open-source e-learning application, used worldwide in the implementation and analysis of cryptographic algorithms.

Get unicode value of a character

private static String toUnicode(char ch) {
    return String.format("\\u%04x", (int) ch);
}

How do you use variables in a simple PostgreSQL script?

I had to do something like this

CREATE OR REPLACE FUNCTION MYFUNC()
RETURNS VOID AS $$
DO
$do$
BEGIN
DECLARE
 myvar int;
 ...
END
$do$
$$ LANGUAGE SQL;

Remove characters after specific character in string, then remove substring?

I second Hightechrider: there is a specialized Url class already built for you.

I must also point out, however, that the PHP's replaceAll uses regular expressions for search pattern, which you can do in .NET as well - look at the RegEx class.

How to define constants in Visual C# like #define in C?

What is the "Visual C#"? There is no such thing. Just C#, or .NET C# :)

Also, Python's convention for constants CONSTANT_NAME is not very common in C#. We are usually using CamelCase according to MSDN standards, e.g. public const string ExtractedMagicString = "vs2019";

Source: Defining constants in C#

Different names of JSON property during serialization and deserialization

I would bind two different getters/setters pair to one variable:

class Coordinates{
    int red;

    @JsonProperty("red")
    public byte getRed() {
      return red;
    }

    public void setRed(byte red) {
      this.red = red;
    }

    @JsonProperty("r")
    public byte getR() {
      return red;
    }

    public void setR(byte red) {
      this.red = red;
    }
}

NoClassDefFoundError - Eclipse and Android

Try this:-

Step 1

Add all the libraries to build pat in Eclipse( means make all libraries referenced libraries)

Step 2

Delete R.java file and again build the project. Don't worry, R.java will automatically get recreated.

Chill :)

How to read input from console in a batch file?

The code snippet in the linked proposed duplicate reads user input.

ECHO A current build of Test Harness exists.
set /p delBuild=Delete preexisting build [y/n]?: 

The user can type as many letters as they want, and it will go into the delBuild variable.

REST API Token-based Authentication

Let me seperate up everything and solve approach each problem in isolation:

Authentication

For authentication, baseauth has the advantage that it is a mature solution on the protocol level. This means a lot of "might crop up later" problems are already solved for you. For example, with BaseAuth, user agents know the password is a password so they don't cache it.

Auth server load

If you dispense a token to the user instead of caching the authentication on your server, you are still doing the same thing: Caching authentication information. The only difference is that you are turning the responsibility for the caching to the user. This seems like unnecessary labor for the user with no gains, so I recommend to handle this transparently on your server as you suggested.

Transmission Security

If can use an SSL connection, that's all there is to it, the connection is secure*. To prevent accidental multiple execution, you can filter multiple urls or ask users to include a random component ("nonce") in the URL.

url = username:[email protected]/api/call/nonce

If that is not possible, and the transmitted information is not secret, I recommend securing the request with a hash, as you suggested in the token approach. Since the hash provides the security, you could instruct your users to provide the hash as the baseauth password. For improved robustness, I recommend using a random string instead of the timestamp as a "nonce" to prevent replay attacks (two legit requests could be made during the same second). Instead of providing seperate "shared secret" and "api key" fields, you can simply use the api key as shared secret, and then use a salt that doesn't change to prevent rainbow table attacks. The username field seems like a good place to put the nonce too, since it is part of the auth. So now you have a clean call like this:

nonce = generate_secure_password(length: 16);
one_time_key = nonce + '-' + sha1(nonce+salt+shared_key);
url = username:[email protected]/api/call

It is true that this is a bit laborious. This is because you aren't using a protocol level solution (like SSL). So it might be a good idea to provide some kind of SDK to users so at least they don't have to go through it themselves. If you need to do it this way, I find the security level appropriate (just-right-kill).

Secure secret storage

It depends who you are trying to thwart. If you are preventing people with access to the user's phone from using your REST service in the user's name, then it would be a good idea to find some kind of keyring API on the target OS and have the SDK (or the implementor) store the key there. If that's not possible, you can at least make it a bit harder to get the secret by encrypting it, and storing the encrypted data and the encryption key in seperate places.

If you are trying to keep other software vendors from getting your API key to prevent the development of alternate clients, only the encrypt-and-store-seperately approach almost works. This is whitebox crypto, and to date, no one has come up with a truly secure solution to problems of this class. The least you can do is still issue a single key for each user so you can ban abused keys.

(*) EDIT: SSL connections should no longer be considered secure without taking additional steps to verify them.

Detecting a mobile browser

var isMobile = {
    Android: function() {
        return navigator.userAgent.match(/Android/i);
    },
    BlackBerry: function() {
        return navigator.userAgent.match(/BlackBerry/i);
    },
    iOS: function() {
        return navigator.userAgent.match(/iPhone|iPad|iPod/i);
    },
    Opera: function() {
        return navigator.userAgent.match(/Opera Mini/i);
    },
    Windows: function() {
        return navigator.userAgent.match(/IEMobile/i) || navigator.userAgent.match(/WPDesktop/i);
    },
    any: function() {
        return (isMobile.Android() || isMobile.BlackBerry() || isMobile.iOS() || isMobile.Opera() || isMobile.Windows());
    }
};

How to use

if( isMobile.any() ) alert('Mobile');

To check to see if the user is on a specific mobile device:

if( isMobile.iOS() ) alert('iOS');

Ref: http://www.abeautifulsite.net/blog/2011/11/detecting-mobile-devices-with-javascript

Enhanced version on github : https://github.com/smali-kazmi/detect-mobile-browser

console.log(result) returns [object Object]. How do I get result.name?

Use console.log(JSON.stringify(result)) to get the JSON in a string format.

EDIT: If your intention is to get the id and other properties from the result object and you want to see it console to know if its there then you can check with hasOwnProperty and access the property if it does exist:

var obj = {id : "007", name : "James Bond"};
console.log(obj);                    // Object { id: "007", name: "James Bond" }
console.log(JSON.stringify(obj));    //{"id":"007","name":"James Bond"}
if (obj.hasOwnProperty("id")){
    console.log(obj.id);             //007
}

How can I disable editing cells in a WPF Datagrid?

If you want to disable editing the entire grid, you can set IsReadOnly to true on the grid. If you want to disable user to add new rows, you set the property CanUserAddRows="False"

<DataGrid IsReadOnly="True" CanUserAddRows="False" />

Further more you can set IsReadOnly on individual columns to disable editing.

Setting button text via javascript

The value of a button element isn't the displayed text, contrary to what happens to input elements of type button.

You can do this :

 b.appendChild(document.createTextNode('test value'));

Demonstration

Can I read the hash portion of the URL on my server-side application (PHP, Ruby, Python, etc.)?

Simple test, accessing http://localhost:8000/hello?foo=bar#this-is-not-sent-to-server

python -c "import SimpleHTTPServer;SimpleHTTPServer.test()"
Serving HTTP on 0.0.0.0 port 8000 ...
localhost - - [02/Jun/2009 12:48:47] code 404, message File not found
localhost - - [02/Jun/2009 12:48:47] "GET /hello?foo=bar HTTP/1.1" 404 -

The server receives the request without the #appendage - anything after the hash tag is simply an anchor lookup on the client.

You can find the anchor name used within the URL via javascript using, as an example:

<script>alert(window.location.hash);</script>

The parse_url() function in PHP can work if you already have the needed URL string including the fragment (http://codepad.org/BDqjtXix):

<?
echo parse_url("http://foo?bar#fizzbuzz",PHP_URL_FRAGMENT);
?>

Output: fizzbuzz

But I don't think PHP receives the fragment information because it's client-only.

What does "collect2: error: ld returned 1 exit status" mean?

The ld returned 1 exit status error is the consequence of previous errors. In your example there is an earlier error - undefined reference to 'clrscr' - and this is the real one. The exit status error just signals that the linking step in the build process encountered some errors. Normally exit status 0 means success, and exit status > 0 means errors.

When you build your program, multiple tools may be run as separate steps to create the final executable. In your case one of those tools is ld, which first reports the error it found (clrscr reference missing), and then it returns the exit status. Since the exit status is > 0, it means an error and is reported.

In many cases tools return as the exit status the number of errors they encountered. So if ld tool finds two errors, its exit status would be 2.

Bootstrap Accordion button toggle "data-parent" not working

Here is a (hopefully) universal patch I developed to fix this problem for BootStrap V3. No special requirements other than plugging in the script.

$(':not(.panel) > [data-toggle="collapse"][data-parent]').click(function() {
    var parent = $(this).data('parent');
    var items = $('[data-toggle="collapse"][data-parent="' + parent + '"]').not(this);
    items.each(function() {
        var target = $(this).data('target') || '#' + $(this).prop('href').split('#')[1];
        $(target).filter('.in').collapse('hide');
    });
});

EDIT: Below is a simplified answer which still meets my needs, and I'm now using a delegated click handler:

$(document.body).on('click', ':not(.panel) > [data-toggle="collapse"][data-parent]', function() {
    var parent = $(this).data('parent');
    var target = $(this).data('target') || $(this).prop('hash');
    $(parent).find('.collapse.in').not(target).collapse('hide');
});

Illegal Character when trying to compile java code

That's a problem related to BOM (Byte Order Mark) character. Byte Order Mark BOM is an Unicode character used for defining a text file byte order and comes in the start of the file. Eclipse doesn't allow this character at the start of your file, so you must delete it. for this purpose, use a rich text editor like Notepad++ and save the file with encoding "UTF-8 without BOM". That should remove the problem.

I have copy pasted the some content from a website to a Notepad++ editor,
it shows the "LS" with black background. Have deleted the "LS" content and 
have copy the same content from notepad++ to java file, it works fine.

Putting a simple if-then-else statement on one line

Moreover, you can still use the "ordinary" if syntax and conflate it into one line with a colon.

if i > 3: print("We are done.")

or

field_plural = None
if field_plural is not None: print("insert into testtable(plural) '{0}'".format(field_plural)) 

filename.whl is not supported wheel on this platform

This can also be caused by using an out-of-date pip with a recent wheel file.

I was very confused, because I was installing numpy-1.10.4+mkl-cp27-cp27m-win_amd64.whl (from here), and it is definitely the correct version for my Python installation (Windows 64-bit Python 2.7.11). I got the "not supported wheel on this platform" error.

Upgrading pip with python -m pip install --upgrade pip solved it.

vertical-align: middle with Bootstrap 2

As well as the previous answers are you could always use the Pull attrib as well:


    <ol class="row" id="possibilities">
       <li class="span6">
         <div class="row">
           <div class="span3">
             <p>some text here</p>
             <p>Text Here too</p>
           </div>
         <figure class="span3 pull-right"><img src="img/screenshots/options.png" alt="Some text" /></figure>
        </div>
 </li>
 <li class="span6">
     <div class="row">
         <figure class="span3"><img src="img/qrcode.png" alt="Some text" /></figure>
         <div class="span3">
             <p>Some text</p>
             <p>Some text here too.</p>
         </div>
     </div>
 </li>

How is Java platform-independent when it needs a JVM to run?

            Technical Article on How java is platform indepedent?

Before going into the detail,first you have to understand what is the mean of platform? Platform consists of the computer hardware(mainly architecture of the microprocessor) and OS. Platform=hardware+Operating System

Anything that is platform indepedent can run on any operating system and hardware.

Java is platform indepedent so java can run on any operating system and hardware. Now question is how is it platform independent?

This is because of the magic of Byte Code which is OS indepedent. When java compiler compiles any code then it generates the byte code not the machine native code(unlike C compiler). Now this byte code needs an interpreter to execute on a machine. This interpreter is JVM. So JVM reads that byte code(that is machine indepedent) amd execute it. Different JVM is designed for different OS and byte code is able to run on different OS.

In case of C or C++(language that are not platform indepedent) compiler generate the .exe file that is OS depedent so when we run this .exe file on another OS it will not run because this file is OS depedent so is not compatible with the another OS.

Finally an intermediate OS indepedent Byte code make the java platform independent.

What is the difference between %g and %f in C?

They are both examples of floating point input/output.

%g and %G are simplifiers of the scientific notation floats %e and %E.

%g will take a number that could be represented as %f (a simple float or double) or %e (scientific notation) and return it as the shorter of the two.

The output of your print statement will depend on the value of sum.

How can I get the class name from a C++ object?

An improvement for @Chubsdad answer,

//main.cpp

using namespace std;

int main(){
A a;
a.run();
}

//A.h
class A{
public:
 A(){};
 void run();
}

//A.cpp
#include <iostream>
#include <typeinfo>
void A::run(){
   cout << (string)typeid(this).name();
}

Which will print:

class A*

Adding extra zeros in front of a number using jQuery?

str could be a number or a string.

formatting("hi",3);
function formatting(str,len)
{
   return ("000000"+str).slice(-len);
}

Add more zeros if needs large digits

Write applications in C or C++ for Android?

I do not know a tutorial but a good development tool: Airplay SDK from Ideaworks Labs. (Recently rebranded "Marmelade") Using C/C++ you can build apps for Windows Mobile, iPhones, Android. The only component I didn't like was the GUI composer - a buggy one, but you always can substitute it with the Notepad.

Error related to only_full_group_by when executing a query in MySql

If you have this error with Symfony using doctrine query builder, and if this error is caused by an orderBy :

Pay attention to select the column you want to groupBy, and use addGroupBy instead of groupBy :

$query = $this->createQueryBuilder('smth')->addGroupBy('smth.mycolumn');

Works on Symfony3 -

Is SQL syntax case sensitive?

My understanding is that the SQL standard calls for case-insensitivity. I don't believe any databases follow the standard completely, though.

MySQL has a configuration setting as part of its "strict mode" (a grab bag of several settings that make MySQL more standards-compliant) for case sensitive or insensitive table names. Regardless of this setting, column names are still case-insensitive, although I think it affects how the column-names are displayed. I believe this setting is instance-wide, across all databases within the RDBMS instance, although I'm researching today to confirm this (and hoping the answer is no).

I like how Oracle handles this far better. In straight SQL, identifiers like table and column names are case insensitive. However, if for some reason you really desire to get explicit casing, you can enclose the identifier in double-quotes (which are quite different in Oracle SQL from the single-quotes used to enclose string data). So:

SELECT fieldName
FROM tableName;

will query fieldname from tablename, but

SELECT "fieldName"
FROM "tableName";

will query fieldName from tableName.

I'm pretty sure you could even use this mechanism to insert spaces or other non-standard characters into an identifier.

In this situation if for some reason you found explicitly-cased table and column names desirable it was available to you, but it was still something I would highly caution against.

My convention when I used Oracle on a daily basis was that in code I would put all Oracle SQL keywords in uppercase and all identifiers in lowercase. In documentation I would put all table and column names in uppercase. It was very convenient and readable to be able to do this (although sometimes a pain to type so many capitals in code -- I'm sure I could've found an editor feature to help, here).

In my opinion MySQL is particularly bad for differing about this on different platforms. We need to be able to dump databases on Windows and load them into UNIX, and doing so is a disaster if the installer on Windows forgot to put the RDBMS into case-sensitive mode. (To be fair, part of the reason this is a disaster is our coders made the bad decision, long ago, to rely on the case-sensitivity of MySQL on UNIX.) The people who wrote the Windows MySQL installer made it really convenient and Windows-like, and it was great to move toward giving people a checkbox to say "Would you like to turn on strict mode and make MySQL more standards-compliant?" But it is very convenient for MySQL to differ so signficantly from the standard, and then make matters worse by turning around and differing from its own de facto standard on different platforms. I'm sure that on differing Linux distributions this may be further compounded, as packagers for different distros probably have at times incorporated their own preferred MySQL configuration settings.

Here's another SO question that gets into discussing if case-sensitivity is desirable in an RDBMS.

Print a variable in hexadecimal in Python

Convert the string to an integer base 16 then to hexadecimal.

print hex(int(string, base=16))

These are built-in functions.

http://docs.python.org/2/library/functions.html#int

Example

>>> string = 'AA'
>>> _int = int(string, base=16)
>>> _hex = hex(_int)
>>> print _int
170
>>> print _hex
0xaa
>>> 

Favicon: .ico or .png / correct tags?

I know this is an old question.

Here's another option - attending to different platform requirements - Source

<link rel='shortcut icon' type='image/vnd.microsoft.icon' href='/favicon.ico'> <!-- IE -->
<link rel='apple-touch-icon' type='image/png' href='/icon.57.png'> <!-- iPhone -->
<link rel='apple-touch-icon' type='image/png' sizes='72x72' href='/icon.72.png'> <!-- iPad -->
<link rel='apple-touch-icon' type='image/png' sizes='114x114' href='/icon.114.png'> <!-- iPhone4 -->
<link rel='icon' type='image/png' href='/icon.114.png'> <!-- Opera Speed Dial, at least 144×114 px -->

This is the broadest approach I have found so far.

Ultimately the decision depends on your own needs. Ask yourself, who is your target audience?

UPDATE May 27, 2018: As expected, time goes by and things change. But there's good news too. I found a tool called Real Favicon Generator that generates all the required lines for the icon to work on all modern browsers and platforms. It doesn't handle backwards compatibility though.

The way to check a HDFS directory's size?

hdfs dfs -count <dir>

info from man page:

-count [-q] [-h] [-v] [-t [<storage type>]] [-u] <path> ... :
  Count the number of directories, files and bytes under the paths
  that match the specified file pattern.  The output columns are:
  DIR_COUNT FILE_COUNT CONTENT_SIZE PATHNAME
  or, with the -q option:
  QUOTA REM_QUOTA SPACE_QUOTA REM_SPACE_QUOTA
        DIR_COUNT FILE_COUNT CONTENT_SIZE PATHNAME

How to style dt and dd so they are on the same line?

You can use CSS Grid:

_x000D_
_x000D_
dl {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
}
_x000D_
<dl>
<dt>Title 1</dt>
<dd>Description 1</dd>
<dt>Title 2</dt>
<dd>Description 2</dd>
<dt>Title 3</dt>
<dd>Description 3</dd>
<dt>Title 4</dt>
<dd>Description 4</dd>
<dt>Title 5</dt>
<dd>Description 5</dd>
</dl>
_x000D_
_x000D_
_x000D_

Android Closing Activity Programmatically

What about the Activity.finish() method (quoting) :

Call this when your activity is done and should be closed.

What's the best way to share data between activities?

Do what google commands you to do! here: http://developer.android.com/resources/faq/framework.html#3

  • Primitive Data Types
  • Non-Persistent Objects
  • Singleton class - my favorite :D
  • A public static field/method
  • A HashMap of WeakReferences to Objects
  • Persistent Objects (Application Preferences, Files, contentProviders, SQLite DB)

Nested ng-repeat

If you have a big nested JSON object and using it across several screens, you might face performance issues in page loading. I always go for small individual JSON objects and query the related objects as lazy load only where they are required.

you can achieve it using ng-init

<td class="lectureClass" ng-repeat="s in sessions" ng-init='presenters=getPresenters(s.id)'>
      {{s.name}}
      <div class="presenterClass" ng-repeat="p in presenters">
          {{p.name}}
      </div>
</td> 

The code on the controller side should look like below

$scope.getPresenters = function(id) {
    return SessionPresenters.get({id: id});
};

While the API factory is as follows:

angular.module('tryme3App').factory('SessionPresenters', function ($resource, DateUtils) {

        return $resource('api/session.Presenters/:id', {}, {
            'query': { method: 'GET', isArray: true},
            'get': {
                method: 'GET', isArray: true
            },
            'update': { method:'PUT' }
        });
    });

How to use aria-expanded="true" to change a css property

Why javascript when you can use just css?

_x000D_
_x000D_
a[aria-expanded="true"]{_x000D_
  background-color: #42DCA3;_x000D_
}
_x000D_
<li class="active">_x000D_
   <a href="#3a" class="btn btn-default btn-lg" data-toggle="tab" aria-expanded="true"> _x000D_
       <span class="network-name">Google+</span>_x000D_
   </a>_x000D_
</li>_x000D_
<li class="active">_x000D_
   <a href="#3a" class="btn btn-default btn-lg" data-toggle="tab" aria-expanded="false"> _x000D_
       <span class="network-name">Google+</span>_x000D_
   </a>_x000D_
</li>
_x000D_
_x000D_
_x000D_

How do I get NuGet to install/update all the packages in the packages.config?

I believe the first thing you need to do is enable the package restore feature. See also here. This is done at the solution (not project) level.

But that won't get you all the way -- I ran into a similar issue after having enabled the restore feature. (VS2013, NuGet 2.8.)

It turned out I had (unintentionally) committed the packages to source control when I committed the project -- but Visual Studio (and the source control plugin) had helpfully ignored the binaries when performing the check-in.

The problem arose when I created a release branch. My local copy of the dev/main/trunk branch had the binaries, because that's where I had originally installed/downloaded the packages.
However, in the new release branch,

  • the package folders and .nupkg files were all there -- so NuGet didn't think there was anything to restore;
  • but at the same time, none of the DLLs were present -- i.e. the third-party references were missing -- so I couldn't build.

I deleted all the package folders in $(SolutionDir)/packages (under the release branch) and then ran a full rebuild, and this time the build succeeded.
... and then of course I went back and removed the package folders from source control (in the trunk and release branch). I'm not clear (yet) on whether the repositories.config file should be removed as well.

Many of the components installed for you by the project templates -- at least for web projects -- are NuGet packages. That is, this issue is not limited to packages you've added.
So enable package restore immediately after creating the project/solution, and before you perform an initial check-in, clear the packages folder (and make sure you commit the .nuget folder to source control).

Disclaimer: I saw another answer here on SO which indicated that clearing the packages folder was part of the resolution. That put me on the right track, so I'd like to give the author credit, but I can no longer locate that question/answer. I'll post an edit if I stumble across it.

I'd also note that Update-Package -reinstall will modify the .sln and .csproj/.vbproj files. At least that's what it did in my case. Which IMHO makes this option much less attractive.

Extract column values of Dataframe as List in Apache Spark

List<String> whatever_list = df.toJavaRDD().map(new Function<Row, String>() {
    public String call(Row row) {
        return row.getAs("column_name").toString();
    }
}).collect();

logger.info(String.format("list is %s",whatever_list)); //verification

Since no one has given any solution in java(Real Programming Language) Can thank me later

SQL Server ORDER BY date and nulls last

smalldatetime has range up to June 6, 2079 so you can use

ORDER BY ISNULL(Next_Contact_Date, '2079-06-05T23:59:00')

If no legitimate records will have that date.

If this is not an assumption you fancy relying on a more robust option is sorting on two columns.

ORDER BY CASE WHEN Next_Contact_Date IS NULL THEN 1 ELSE 0 END, Next_Contact_Date

Both of the above suggestions are not able to use an index to avoid a sort however and give similar looking plans.

enter image description here

One other possibility if such an index exists is

SELECT 1 AS Grp, Next_Contact_Date 
FROM T 
WHERE Next_Contact_Date IS NOT NULL
UNION ALL
SELECT 2 AS Grp, Next_Contact_Date 
FROM T 
WHERE Next_Contact_Date IS NULL
ORDER BY Grp, Next_Contact_Date

Plan

Image library for Python 3

Depending on what is needed, scikit-image may be the best choice, with manipulations going way beyond PIL and the current version of Pillow. Very well-maintained, at least as much as Pillow. Also, the underlying data structures are from Numpy and Scipy, which makes its code incredibly interoperable. Examples that pillow can't handle:

Region Adjacency Graph Merging

Radon Transform

Histogram of oriented gradients

Approximate and subdivide polygons

You can see its power in the gallery. This paper provides a great intro to it. Good luck!

One line if statement not working

Both the shell and C one-line constructs work (ruby 1.9.3p429):

# Shell format
irb(main):022:0> true && "Yes" || "No"
=> "Yes"
irb(main):023:0> false && "Yes" || "No"
=> "No"

# C format
irb(main):024:0> true ? "Yes" : "No"
=> "Yes"
irb(main):025:0> false ? "Yes" : "No"
=> "No"

How to add message box with 'OK' button?

Since in your situation you only want to notify the user with a short and simple message, a Toast would make for a better user experience.

Toast.makeText(getApplicationContext(), "Data saved", Toast.LENGTH_LONG).show();

Update: A Snackbar is recommended now instead of a Toast for Material Design apps.

If you have a more lengthy message that you want to give the reader time to read and understand, then you should use a DialogFragment. (The documentation currently recommends wrapping your AlertDialog in a fragment rather than calling it directly.)

Make a class that extends DialogFragment:

public class MyDialogFragment extends DialogFragment {
    @Override
    public Dialog onCreateDialog(Bundle savedInstanceState) {

        // Use the Builder class for convenient dialog construction
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setTitle("App Title");
        builder.setMessage("This is an alert with no consequence");
        builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                // You don't have to do anything here if you just 
                // want it dismissed when clicked
            }
        });

        // Create the AlertDialog object and return it
        return builder.create();
    }
}

Then call it when you need it in your activity:

DialogFragment dialog = new MyDialogFragment();
dialog.show(getSupportFragmentManager(), "MyDialogFragmentTag");

See also

enter image description here

How to customise file type to syntax associations in Sublime Text?

for ST3

$language = "language u wish"

if exists,

go to ~/.config/sublime-text-3/Packages/User/$language.sublime-settings

else

create ~/.config/sublime-text-3/Packages/User/$language.sublime-settings

and set

{ "extensions": [ "yourextension" ] }

This way allows you to enable syntax for composite extensions (e.g. sql.mustache, js.php, etc ... )

How to capture the screenshot of a specific element rather than entire page using Selenium Webdriver?

I'm using a modified version of @Brook's answer and is working fine even for elements that needs the page to be scrolled.

public void TakeScreenshot(string fileNameWithoutExtension, IWebElement element)
{
    // Scroll to the element if necessary
    var actions = new Actions(_driver);
    actions.MoveToElement(element);
    actions.Perform();
    // Get the element position (scroll-aware)
    var locationWhenScrolled = ((RemoteWebElement) element).LocationOnScreenOnceScrolledIntoView;
    var fileName = fileNameWithoutExtension + ".png";
    var byteArray = ((ITakesScreenshot) _driver).GetScreenshot().AsByteArray;
    using (var screenshot = new System.Drawing.Bitmap(new System.IO.MemoryStream(byteArray)))
    {
        var location = locationWhenScrolled;
        // Fix location if necessary to avoid OutOfMemory Exception
        if (location.X + element.Size.Width > screenshot.Width)
        {
            location.X = screenshot.Width - element.Size.Width;
        }
        if (location.Y + element.Size.Height > screenshot.Height)
        {
            location.Y = screenshot.Height - element.Size.Height;
        }
        // Crop the screenshot
        var croppedImage = new System.Drawing.Rectangle(location.X, location.Y, element.Size.Width, element.Size.Height);
        using (var clone = screenshot.Clone(croppedImage, screenshot.PixelFormat))
        {
            clone.Save(fileName, ImageFormat.Png);
        }
    }
}

The two ifs were necessary (at least for the chrome driver) because the size of the crop exceeded in 1 pixel the screenshot size, when scrolling was needed.

How to convert Rows to Columns in Oracle?

 select * FROM doc_tab
    PIVOT
    (
    Min(document_id)
    FOR document_type IN ('Voters ID','Pan card','Drivers licence')
    ) 

outputs as this

enter image description here

sql fiddle demo here

Simplest way to form a union of two lists

If it is two IEnumerable lists you can't use AddRange, but you can use Concat.

IEnumerable<int> first = new List<int>{1,1,2,3,5};
IEnumerable<int> second = new List<int>{8,13,21,34,55};

var allItems = first.Concat(second);
// 1,1,2,3,5,8,13,21,34,55

Why I am Getting Error 'Channel is unrecoverably broken and will be disposed!'

Have you used another UI thread? You shouldn't use more than 1 UI thread and make it look like a sandwich. Doing this will cause memory leaks.

I have solved a similar issue 2 days ago...

To keep things short: The main thread can have many UI threads to do multiple works, but if one sub-thread containing a UI thread is inside it, The UI thread may not have finished its work yet while it's parent thread has already finished its work, this causes memory leaks.

For example...for Fragment & UI application...this will cause memory leaks.

getActivity().runOnUiThread(new Runnable(){

   public void run() {//No.1

  ShowDataScreen();

getActivity().runOnUiThread(new Runnable(){

    public void run() {//No.2

Toast.makeText(getActivity(), "This is error way",Toast.LENGTH_SHORT).show();

    }});// end of No.2 UI new thread

}});// end of No.1 UI new thread

My solution is rearrange as below:

getActivity().runOnUiThread(new Runnable(){

   public void run() {//No.1

ShowDataScreen();

}});// end of No.1 UI new thread        

getActivity().runOnUiThread(new Runnable(){

   public void run() {//No.2

Toast.makeText(getActivity(), "This is correct way",Toast.LENGTH_SHORT).show();

}});// end of No.2 UI new thread

for you reference.

I am Taiwanese, I am glad to answer here once more.

Why would we call cin.clear() and cin.ignore() after reading input?

use cin.ignore(1000,'\n') to clear all of chars of the previous cin.get() in the buffer and it will choose to stop when it meet '\n' or 1000 chars first.

How do you create a Distinct query in HQL

It's worth noting that the distinct keyword in HQL does not map directly to the distinct keyword in SQL.

If you use the distinct keyword in HQL, then sometimes Hibernate will use the distinct SQL keyword, but in some situations it will use a result transformer to produce distinct results. For example when you are using an outer join like this:

select distinct o from Order o left join fetch o.lineItems

It is not possible to filter out duplicates at the SQL level in this case, so Hibernate uses a ResultTransformer to filter duplicates after the SQL query has been performed.

Javascript: The prettiest way to compare one value against multiple values

What i use to do, is put those multiple values in an array like

var options = [foo, bar];

and then, use indexOf()

if(options.indexOf(foobar) > -1){
   //do something
}

for prettiness:

if([foo, bar].indexOf(foobar) +1){
   //you can't get any more pretty than this :)
}

and for the older browsers:
( https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Array/IndexOf )

if (!Array.prototype.indexOf) {
    Array.prototype.indexOf = function (searchElement /*, fromIndex */ ) {
        "use strict";
        if (this == null) {
            throw new TypeError();
        }
        var t = Object(this);
        var len = t.length >>> 0;
        if (len === 0) {
            return -1;
        }
        var n = 0;
        if (arguments.length > 0) {
            n = Number(arguments[1]);
            if (n != n) { // shortcut for verifying if it's NaN
                n = 0;
            } else if (n != 0 && n != Infinity && n != -Infinity) {
                n = (n > 0 || -1) * Math.floor(Math.abs(n));
            }
        }
        if (n >= len) {
            return -1;
        }
        var k = n >= 0 ? n : Math.max(len - Math.abs(n), 0);
        for (; k < len; k++) {
            if (k in t && t[k] === searchElement) {
                return k;
            }
        }
        return -1;
    }
}

When does a cookie with expiration time 'At end of session' expire?

Cookies that 'expire at end of the session' expire unpredictably from the user's perspective!

On iOS with Safari they expire whenever you switch apps!

On Android with Chrome they don't expire when you close the browser.

On Windows desktop running Chrome they expire when you close the browser. That's not when you close your website's tab; its when you close all tabs. Nor do they expire if there are any other browser windows open. If users run web apps as windows they might not even know they are browser windows. So your cookie's life depends on what the user is doing with some apparently unrelated app.

Android: Clear Activity Stack

For Xamarin Developers, you can use:

intent.SetFlags(ActivityFlags.NewTask | ActivityFlags.ClearTask);

Pass multiple parameters to rest API - Spring

you can pass multiple params in url like

http://localhost:2000/custom?brand=dell&limit=20&price=20000&sort=asc

and in order to get this query fields , you can use map like

    @RequestMapping(method = RequestMethod.GET, value = "/custom")
    public String controllerMethod(@RequestParam Map<String, String> customQuery) {

        System.out.println("customQuery = brand " + customQuery.containsKey("brand"));
        System.out.println("customQuery = limit " + customQuery.containsKey("limit"));
        System.out.println("customQuery = price " + customQuery.containsKey("price"));
        System.out.println("customQuery = other " + customQuery.containsKey("other"));
        System.out.println("customQuery = sort " + customQuery.containsKey("sort"));

        return customQuery.toString();
    }

Warning: Cannot modify header information - headers already sent by ERROR

Those blank lines between your ?> and <?php tags are being sent to the client.

When the first one of those is sent, it causes your headers to be sent first.

Once that happens, you can't modify the headers any more.

Remove those unnecessary tags, have it all in one big <?php block.

How to scroll table's "tbody" independent of "thead"?

mandatory parts:

tbody {
    overflow-y: scroll;  (could be: 'overflow: scroll' for the two axes)
    display: block;
    with: xxx (a number or 100%)
}

thead {
    display: inline-block;
}

React-Router: No Not Found Route?

In newer versions of react-router you want to wrap the routes in a Switch which only renders the first matched component. Otherwise you would see multiple components rendered.

For example:

import React from 'react';
import ReactDOM from 'react-dom';
import {
  BrowserRouter as Router,
  Route,
  browserHistory,
  Switch
} from 'react-router-dom';

import App from './app/App';
import Welcome from './app/Welcome';
import NotFound from './app/NotFound';

const Root = () => (
  <Router history={browserHistory}>
    <Switch>
      <Route exact path="/" component={App}/>
      <Route path="/welcome" component={Welcome}/>
      <Route component={NotFound}/>
    </Switch>
  </Router>
);

ReactDOM.render(
  <Root/>,
  document.getElementById('root')
);

Which is best data type for phone number in MySQL and what should Java type mapping for it be?

Consider using the E.164 format. For full international support, you'd need a VARCHAR of 15 digits.

See Twilio's recommendation for more information on localization of phone numbers.

How to convert map to url query string?

To improve a little bit upon @eclipse's answer: In Javaland a request parameter map is usually represented as a Map<String, String[]>, a Map<String, List<String>> or possibly some kind of MultiValueMap<String, String> which is sort of the same thing. In any case: a parameter can usually have multiple values. A Java 8 solution would therefore be something along these lines:

public String getQueryString(HttpServletRequest request, String encoding) {
    Map<String, String[]> parameters = request.getParameterMap();

    return parameters.entrySet().stream()
            .flatMap(entry -> encodeMultiParameter(entry.getKey(), entry.getValue(), encoding))
            .reduce((param1, param2) -> param1 + "&" + param2)
            .orElse("");
}

private Stream<String> encodeMultiParameter(String key, String[] values, String encoding) {
    return Stream.of(values).map(value -> encodeSingleParameter(key, value, encoding));
}

private String encodeSingleParameter(String key, String value, String encoding) {
    return urlEncode(key, encoding) + "=" + urlEncode(value, encoding);
}

private String urlEncode(String value, String encoding) {
    try {
        return URLEncoder.encode(value, encoding);
    } catch (UnsupportedEncodingException e) {
        throw new IllegalArgumentException("Cannot url encode " + value, e);
    }
}

Differences between fork and exec

The prime example to understand the fork() and exec() concept is the shell,the command interpreter program that users typically executes after logging into the system.The shell interprets the first word of command line as a command name

For many commands,the shell forks and the child process execs the command associated with the name treating the remaining words on the command line as parameters to the command.

The shell allows three types of commands. First, a command can be an executable file that contains object code produced by compilation of source code (a C program for example). Second, a command can be an executable file that contains a sequence of shell command lines. Finally, a command can be an internal shell command.(instead of an executable file ex->cd,ls etc.)

How to add bootstrap to an angular-cli project

You have many ways to add Bootstrap 4 in your Angular project:

  • Including the Bootstrap CSS and JavaScript files in the section of the index.html file of your Angular project with a and tags,

  • Importing the Bootstrap CSS file in the global styles.css file of your Angular project with an @import keyword.

  • Adding the Bootstrap CSS and JavaScript files in the styles and scripts arrays of the angular.json file of your project

Email Address Validation in Android on EditText

Java:

public static boolean isValidEmail(CharSequence target) {
    return (!TextUtils.isEmpty(target) && Patterns.EMAIL_ADDRESS.matcher(target).matches());
}

Kotlin:

fun CharSequence?.isValidEmail() = !isNullOrEmpty() && Patterns.EMAIL_ADDRESS.matcher(this).matches()

Edit: It will work On Android 2.2+ onwards !!

Edit: Added missing ;

How to redirect to a route in laravel 5 by using href tag if I'm not using blade or any template?

In you app config file change the url to localhost/example/public

Then when you want to link to something

<a href="{{ url('page') }}">Some Text</a>

without blade

<a href="<?php echo url('page') ?>">Some Text</a>

How to declare empty list and then add string in scala?

As mentioned in an above answer, the Scala List is an immutable collection. You can create an empty list with .empty[A]. Then you can use a method :+ , +: or :: in order to add element to the list.

scala> val strList = List.empty[String]
strList: List[String] = List()

scala> strList:+ "Text"
res3: List[String] = List(Text)

scala> val mapList = List.empty[Map[String, Any]]
mapList: List[Map[String,Any]] = List()

scala> mapList :+ Map("1" -> "ok")
res4: List[Map[String,Any]] = List(Map(1 -> ok))

How to pass a PHP variable using the URL

In your link.php your echo statement must be like this:

echo '<a href="pass.php?link=' . $a . '>Link 1</a>';
echo '<a href="pass.php?link=' . $b . '">Link 2</a>';

Then in your pass.php you cannot use $a because it was not initialized with your intended string value.

You can directly compare it to a string like this:

if($_GET['link'] == 'Link1')

Another way is to initialize the variable first to the same thing you did with link.php. And, a much better way is to include the $a and $b variables in a single PHP file, then include that in all pages where you are going to use those variables as Tim Cooper mention on his post. You can also include this in a session.

How to initialise memory with new operator in C++?

There is number of methods to allocate an array of intrinsic type and all of these method are correct, though which one to choose, depends...

Manual initialisation of all elements in loop

int* p = new int[10];
for (int i = 0; i < 10; i++)
    p[i] = 0;

Using std::memset function from <cstring>

int* p = new int[10];
std::memset(p, 0, sizeof *p * 10);

Using std::fill_n algorithm from <algorithm>

int* p = new int[10];
std::fill_n(p, 10, 0);

Using std::vector container

std::vector<int> v(10); // elements zero'ed

If C++11 is available, using initializer list features

int a[] = { 1, 2, 3 }; // 3-element static size array
vector<int> v = { 1, 2, 3 }; // 3-element array but vector is resizeable in runtime

How to call external JavaScript function in HTML

If a <script> has a src then the text content of the element will be not be executed as JS (although it will appear in the DOM).

You need to use multiple script elements.

  1. a <script> to load the external script
  2. a <script> to hold your inline code (with the call to the function in the external script)

    scroll_messages();

RESTful API methods; HEAD & OPTIONS

As per: http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html

9.2 OPTIONS

The OPTIONS method represents a request for information about the communication options available on the request/response chain identified by the Request-URI. This method allows the client to determine the options and/or requirements associated with a resource, or the capabilities of a server, without implying a resource action or initiating a resource retrieval.

Responses to this method are not cacheable.

If the OPTIONS request includes an entity-body (as indicated by the presence of Content-Length or Transfer-Encoding), then the media type MUST be indicated by a Content-Type field. Although this specification does not define any use for such a body, future extensions to HTTP might use the OPTIONS body to make more detailed queries on the server. A server that does not support such an extension MAY discard the request body.

If the Request-URI is an asterisk ("*"), the OPTIONS request is intended to apply to the server in general rather than to a specific resource. Since a server's communication options typically depend on the resource, the "*" request is only useful as a "ping" or "no-op" type of method; it does nothing beyond allowing the client to test the capabilities of the server. For example, this can be used to test a proxy for HTTP/1.1 compliance (or lack thereof).

If the Request-URI is not an asterisk, the OPTIONS request applies only to the options that are available when communicating with that resource.

A 200 response SHOULD include any header fields that indicate optional features implemented by the server and applicable to that resource (e.g., Allow), possibly including extensions not defined by this specification. The response body, if any, SHOULD also include information about the communication options. The format for such a body is not defined by this specification, but might be defined by future extensions to HTTP. Content negotiation MAY be used to select the appropriate response format. If no response body is included, the response MUST include a Content-Length field with a field-value of "0".

The Max-Forwards request-header field MAY be used to target a specific proxy in the request chain. When a proxy receives an OPTIONS request on an absoluteURI for which request forwarding is permitted, the proxy MUST check for a Max-Forwards field. If the Max-Forwards field-value is zero ("0"), the proxy MUST NOT forward the message; instead, the proxy SHOULD respond with its own communication options. If the Max-Forwards field-value is an integer greater than zero, the proxy MUST decrement the field-value when it forwards the request. If no Max-Forwards field is present in the request, then the forwarded request MUST NOT include a Max-Forwards field.

9.4 HEAD

The HEAD method is identical to GET except that the server MUST NOT return a message-body in the response. The metainformation contained in the HTTP headers in response to a HEAD request SHOULD be identical to the information sent in response to a GET request. This method can be used for obtaining metainformation about the entity implied by the request without transferring the entity-body itself. This method is often used for testing hypertext links for validity, accessibility, and recent modification.

The response to a HEAD request MAY be cacheable in the sense that the information contained in the response MAY be used to update a previously cached entity from that resource. If the new field values indicate that the cached entity differs from the current entity (as would be indicated by a change in Content-Length, Content-MD5, ETag or Last-Modified), then the cache MUST treat the cache entry as stale.

InputStream from a URL

Use java.net.URL#openStream() with a proper URL (including the protocol!). E.g.

InputStream input = new URL("http://www.somewebsite.com/a.txt").openStream();
// ...

See also:

Creating a Facebook share button with customized url, title and image

This is the code as 2017:

<i class="fa fa-facebook-square"></i>
<a href="#" onclick="window.open('https://www.facebook.com/sharer/sharer.php?u='+encodeURIComponent(location.href),'facebook-share-dialog','width=626,height=436');return false;">Share on Facebook</a>

Facebook now takes all data from OG metatags.

NOTE: This code assumes you have OG metatags on in site's code.

Source

How to preventDefault on anchor tags?

The easiest solution I have found is this one :

<a href="#" ng-click="do(); $event.preventDefault()">Click</a>

Android check permission for LocationManager

If you simply want to check for permissions (rather than request for permissions), I wrote a simple extension like so:

fun BaseActivity.checkPermission(permissionName: String): Boolean {
        return if (Build.VERSION.SDK_INT >= 23) {
            val granted =
                ContextCompat.checkSelfPermission(this, permissionName)
            granted == PackageManager.PERMISSION_GRANTED
        } else {
            val granted =
                PermissionChecker.checkSelfPermission(this, permissionName)
            granted == PermissionChecker.PERMISSION_GRANTED
        }
    }

Now, if I want to check for a permission I can simply pass in a permission like so:

checkPermission(Manifest.permission.READ_CONTACTS)

How do I fix the error 'Named Pipes Provider, error 40 - Could not open a connection to' SQL Server'?

And the simplest solution - check if your slash is back...

I spent about an hour trying to figure out what's wrong with SERVER/INSTANCENAME when everything is configured correctly, named pipes, user access rights... and suddenly it struck me, it's not a slash, it's a backslash (\).

The horror, the shame...

Convert JS Object to form data

Try JSON.stringify function as below

var postData = JSON.stringify(item);
var formData = new FormData();
formData.append("postData",postData );

How can I add the sqlite3 module to Python?

if you have error in Sqlite built in python you can use Conda to solve this conflict

conda install sqlite

My docker container has no internet

Originally my docker container was able to reach the external internet (This is a docker service/container running on an Amazon EC2).

Since my app is an API, I followed up the creation of my container (it succeeded in pulling all the packages it needed) with updating my IP Tables to route all traffic from port 80 to the port that my API (running on docker) was listening on.

Then, later when I tried rebuilding the container it failed. After much struggle, I discovered that my previous step (setting the IPTable port forwarding rule) messed up the docker's external networking capability.

Solution: Stop your IPTable service:

sudo service iptables stop

Restart The Docker Daemon:

sudo service docker restart

Then, try rebuilding your container. Hope this helps.


Follow Up

I completely overlooked that I did not need to mess with the IP Tables to forward incoming traffic to 80 to the port that the API running on docker was running on. Instead, I just aliased port 80 to the port the API in docker was running on:

docker run -d -p 80:<api_port> <image>:<tag> <command to start api>

How to distinguish mouse "click" and "drag"

In case you are already using jQuery:

var $body = $('body');
$body.on('mousedown', function (evt) {
  $body.on('mouseup mousemove', function handler(evt) {
    if (evt.type === 'mouseup') {
      // click
    } else {
      // drag
    }
    $body.off('mouseup mousemove', handler);
  });
});

Pan & Zoom Image

After using samples from this question I've made complete version of pan & zoom app with proper zooming relative to mouse pointer. All pan & zoom code has been moved to separate class called ZoomBorder.

ZoomBorder.cs

using System.Linq;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;

namespace PanAndZoom
{
  public class ZoomBorder : Border
  {
    private UIElement child = null;
    private Point origin;
    private Point start;

    private TranslateTransform GetTranslateTransform(UIElement element)
    {
      return (TranslateTransform)((TransformGroup)element.RenderTransform)
        .Children.First(tr => tr is TranslateTransform);
    }

    private ScaleTransform GetScaleTransform(UIElement element)
    {
      return (ScaleTransform)((TransformGroup)element.RenderTransform)
        .Children.First(tr => tr is ScaleTransform);
    }

    public override UIElement Child
    {
      get { return base.Child; }
      set
      {
        if (value != null && value != this.Child)
          this.Initialize(value);
        base.Child = value;
      }
    }

    public void Initialize(UIElement element)
    {
      this.child = element;
      if (child != null)
      {
        TransformGroup group = new TransformGroup();
        ScaleTransform st = new ScaleTransform();
        group.Children.Add(st);
        TranslateTransform tt = new TranslateTransform();
        group.Children.Add(tt);
        child.RenderTransform = group;
        child.RenderTransformOrigin = new Point(0.0, 0.0);
        this.MouseWheel += child_MouseWheel;
        this.MouseLeftButtonDown += child_MouseLeftButtonDown;
        this.MouseLeftButtonUp += child_MouseLeftButtonUp;
        this.MouseMove += child_MouseMove;
        this.PreviewMouseRightButtonDown += new MouseButtonEventHandler(
          child_PreviewMouseRightButtonDown);
      }
    }

    public void Reset()
    {
      if (child != null)
      {
        // reset zoom
        var st = GetScaleTransform(child);
        st.ScaleX = 1.0;
        st.ScaleY = 1.0;

        // reset pan
        var tt = GetTranslateTransform(child);
        tt.X = 0.0;
        tt.Y = 0.0;
      }
    }

    #region Child Events

        private void child_MouseWheel(object sender, MouseWheelEventArgs e)
        {
            if (child != null)
            {
                var st = GetScaleTransform(child);
                var tt = GetTranslateTransform(child);

                double zoom = e.Delta > 0 ? .2 : -.2;
                if (!(e.Delta > 0) && (st.ScaleX < .4 || st.ScaleY < .4))
                    return;

                Point relative = e.GetPosition(child);
                double absoluteX;
                double absoluteY;

                absoluteX = relative.X * st.ScaleX + tt.X;
                absoluteY = relative.Y * st.ScaleY + tt.Y;

                st.ScaleX += zoom;
                st.ScaleY += zoom;

                tt.X = absoluteX - relative.X * st.ScaleX;
                tt.Y = absoluteY - relative.Y * st.ScaleY;
            }
        }

        private void child_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            if (child != null)
            {
                var tt = GetTranslateTransform(child);
                start = e.GetPosition(this);
                origin = new Point(tt.X, tt.Y);
                this.Cursor = Cursors.Hand;
                child.CaptureMouse();
            }
        }

        private void child_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
        {
            if (child != null)
            {
                child.ReleaseMouseCapture();
                this.Cursor = Cursors.Arrow;
            }
        }

        void child_PreviewMouseRightButtonDown(object sender, MouseButtonEventArgs e)
        {
            this.Reset();
        }

        private void child_MouseMove(object sender, MouseEventArgs e)
        {
            if (child != null)
            {
                if (child.IsMouseCaptured)
                {
                    var tt = GetTranslateTransform(child);
                    Vector v = start - e.GetPosition(this);
                    tt.X = origin.X - v.X;
                    tt.Y = origin.Y - v.Y;
                }
            }
        }

        #endregion
    }
}

MainWindow.xaml

<Window x:Class="PanAndZoom.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:local="clr-namespace:PanAndZoom"
        Title="PanAndZoom" Height="600" Width="900" WindowStartupLocation="CenterScreen">
    <Grid>
        <local:ZoomBorder x:Name="border" ClipToBounds="True" Background="Gray">
            <Image Source="image.jpg"/>
        </local:ZoomBorder>
    </Grid>
</Window>

MainWindow.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace PanAndZoom
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }
    }
}

What is the difference between instanceof and Class.isAssignableFrom(...)?

There is yet another difference. If the type (Class) to test against is dynamic, e.g. passed as a method parameter, then instanceof won't cut it for you.

boolean test(Class clazz) {
   return (this instanceof clazz); // clazz cannot be resolved to a type.
}

but you can do:

boolean test(Class clazz) {
   return (clazz.isAssignableFrom(this.getClass())); // okidoki
}

Oops, I see this answer is already covered. Maybe this example is helpful to someone.

Format specifier %02x

You are actually getting the correct value out.

The way your x86 (compatible) processor stores data like this, is in Little Endian order, meaning that, the MSB is last in your output.

So, given your output:

10101010

the last two hex values 10 are the Most Significant Byte (2 hex digits = 1 byte = 8 bits (for (possibly unnecessary) clarification).

So, by reversing the memory storage order of the bytes, your value is actually: 01010101.

Hope that clears it up!

Is ConfigurationManager.AppSettings available in .NET Core 2.0?

Yes, ConfigurationManager.AppSettings is available in .NET Core 2.0 after referencing NuGet package System.Configuration.ConfigurationManager.

Credits goes to @JeroenMostert for giving me the solution.

What's the difference between 'r+' and 'a+' when open file in python?

Python opens files almost in the same way as in C:

  • r+ Open for reading and writing. The stream is positioned at the beginning of the file.

  • a+ Open for reading and appending (writing at end of file). The file is created if it does not exist. The initial file position for reading is at the beginning of the file, but output is appended to the end of the file (but in some Unix systems regardless of the current seek position).

How to make gradient background in android

Use this code in drawable folder.

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <solid android:color="#3f5063" />
    <corners
        android:bottomLeftRadius="30dp"
        android:bottomRightRadius="0dp"
        android:topLeftRadius="30dp"
        android:topRightRadius="0dp" />
    <padding
        android:bottom="2dp"
        android:left="2dp"
        android:right="2dp"
        android:top="2dp" />
    <gradient
        android:angle="45"
        android:centerColor="#015664"
        android:endColor="#636969"
        android:startColor="#2ea4e7" />
    <stroke
        android:width="1dp"
        android:color="#000000" />
</shape>

Failed to connect to 127.0.0.1:27017, reason: errno:111 Connection refused

I solved that simply by entering sudo mongo after mongod command.

How to pass integer from one Activity to another?

Their are two methods you can use to pass an integer. One is as shown below.

A.class

Intent myIntent = new Intent(A.this, B.class);
myIntent.putExtra("intVariableName", intValue);
startActivity(myIntent);

B.class

Intent intent = getIntent();
int intValue = intent.getIntExtra("intVariableName", 0);

The other method converts the integer to a string and uses the following code.

A.class

Intent intent = new Intent(A.this, B.class);
Bundle extras = new Bundle();
extras.putString("StringVariableName", intValue + "");
intent.putExtras(extras);
startActivity(intent);

The code above will pass your integer value as a string to class B. On class B, get the string value and convert again as an integer as shown below.

B.class

   Bundle extras = getIntent().getExtras();
   String stringVariableName = extras.getString("StringVariableName");
   int intVariableName = Integer.parseInt(stringVariableName);

how to read certain columns from Excel using Pandas - Python

"usecols" should help, use range of columns (as per excel worksheet, A,B...etc.) below are the examples

  1. Selected Columns
df = pd.read_excel(file_location,sheet_name='Sheet1', usecols="A,C,F")
  1. Range of Columns and selected column
df = pd.read_excel(file_location,sheet_name='Sheet1', usecols="A:F,H")
  1. Multiple Ranges
df = pd.read_excel(file_location,sheet_name='Sheet1', usecols="A:F,H,J:N")
  1. Range of columns
df = pd.read_excel(file_location,sheet_name='Sheet1', usecols="A:N")

What's the best way of scraping data from a website?

You will definitely want to start with a good web scraping framework. Later on you may decide that they are too limiting and you can put together your own stack of libraries but without a lot of scraping experience your design will be much worse than pjscrape or scrapy.

Note: I use the terms crawling and scraping basically interchangeable here. This is a copy of my answer to your Quora question, it's pretty long.

Tools

Get very familiar with either Firebug or Chrome dev tools depending on your preferred browser. This will be absolutely necessary as you browse the site you are pulling data from and map out which urls contain the data you are looking for and what data formats make up the responses.

You will need a good working knowledge of HTTP as well as HTML and will probably want to find a decent piece of man in the middle proxy software. You will need to be able to inspect HTTP requests and responses and understand how the cookies and session information and query parameters are being passed around. Fiddler (http://www.telerik.com/fiddler) and Charles Proxy (http://www.charlesproxy.com/) are popular tools. I use mitmproxy (http://mitmproxy.org/) a lot as I'm more of a keyboard guy than a mouse guy.

Some kind of console/shell/REPL type environment where you can try out various pieces of code with instant feedback will be invaluable. Reverse engineering tasks like this are a lot of trial and error so you will want a workflow that makes this easy.

Language

PHP is basically out, it's not well suited for this task and the library/framework support is poor in this area. Python (Scrapy is a great starting point) and Clojure/Clojurescript (incredibly powerful and productive but a big learning curve) are great languages for this problem. Since you would rather not learn a new language and you already know Javascript I would definitely suggest sticking with JS. I have not used pjscrape but it looks quite good from a quick read of their docs. It's well suited and implements an excellent solution to the problem I describe below.

A note on Regular expressions: DO NOT USE REGULAR EXPRESSIONS TO PARSE HTML. A lot of beginners do this because they are already familiar with regexes. It's a huge mistake, use xpath or css selectors to navigate html and only use regular expressions to extract data from actual text inside an html node. This might already be obvious to you, it becomes obvious quickly if you try it but a lot of people waste a lot of time going down this road for some reason. Don't be scared of xpath or css selectors, they are WAY easier to learn than regexes and they were designed to solve this exact problem.

Javascript-heavy sites

In the old days you just had to make an http request and parse the HTML reponse. Now you will almost certainly have to deal with sites that are a mix of standard HTML HTTP request/responses and asynchronous HTTP calls made by the javascript portion of the target site. This is where your proxy software and the network tab of firebug/devtools comes in very handy. The responses to these might be html or they might be json, in rare cases they will be xml or something else.

There are two approaches to this problem:

The low level approach:

You can figure out what ajax urls the site javascript is calling and what those responses look like and make those same requests yourself. So you might pull the html from http://example.com/foobar and extract one piece of data and then have to pull the json response from http://example.com/api/baz?foo=b... to get the other piece of data. You'll need to be aware of passing the correct cookies or session parameters. It's very rare, but occasionally some required parameters for an ajax call will be the result of some crazy calculation done in the site's javascript, reverse engineering this can be annoying.

The embedded browser approach:

Why do you need to work out what data is in html and what data comes in from an ajax call? Managing all that session and cookie data? You don't have to when you browse a site, the browser and the site javascript do that. That's the whole point.

If you just load the page into a headless browser engine like phantomjs it will load the page, run the javascript and tell you when all the ajax calls have completed. You can inject your own javascript if necessary to trigger the appropriate clicks or whatever is necessary to trigger the site javascript to load the appropriate data.

You now have two options, get it to spit out the finished html and parse it or inject some javascript into the page that does your parsing and data formatting and spits the data out (probably in json format). You can freely mix these two options as well.

Which approach is best?

That depends, you will need to be familiar and comfortable with the low level approach for sure. The embedded browser approach works for anything, it will be much easier to implement and will make some of the trickiest problems in scraping disappear. It's also quite a complex piece of machinery that you will need to understand. It's not just HTTP requests and responses, it's requests, embedded browser rendering, site javascript, injected javascript, your own code and 2-way interaction with the embedded browser process.

The embedded browser is also much slower at scale because of the rendering overhead but that will almost certainly not matter unless you are scraping a lot of different domains. Your need to rate limit your requests will make the rendering time completely negligible in the case of a single domain.

Rate Limiting/Bot behaviour

You need to be very aware of this. You need to make requests to your target domains at a reasonable rate. You need to write a well behaved bot when crawling websites, and that means respecting robots.txt and not hammering the server with requests. Mistakes or negligence here is very unethical since this can be considered a denial of service attack. The acceptable rate varies depending on who you ask, 1req/s is the max that the Google crawler runs at but you are not Google and you probably aren't as welcome as Google. Keep it as slow as reasonable. I would suggest 2-5 seconds between each page request.

Identify your requests with a user agent string that identifies your bot and have a webpage for your bot explaining it's purpose. This url goes in the agent string.

You will be easy to block if the site wants to block you. A smart engineer on their end can easily identify bots and a few minutes of work on their end can cause weeks of work changing your scraping code on your end or just make it impossible. If the relationship is antagonistic then a smart engineer at the target site can completely stymie a genius engineer writing a crawler. Scraping code is inherently fragile and this is easily exploited. Something that would provoke this response is almost certainly unethical anyway, so write a well behaved bot and don't worry about this.

Testing

Not a unit/integration test person? Too bad. You will now have to become one. Sites change frequently and you will be changing your code frequently. This is a large part of the challenge.

There are a lot of moving parts involved in scraping a modern website, good test practices will help a lot. Many of the bugs you will encounter while writing this type of code will be the type that just return corrupted data silently. Without good tests to check for regressions you will find out that you've been saving useless corrupted data to your database for a while without noticing. This project will make you very familiar with data validation (find some good libraries to use) and testing. There are not many other problems that combine requiring comprehensive tests and being very difficult to test.

The second part of your tests involve caching and change detection. While writing your code you don't want to be hammering the server for the same page over and over again for no reason. While running your unit tests you want to know if your tests are failing because you broke your code or because the website has been redesigned. Run your unit tests against a cached copy of the urls involved. A caching proxy is very useful here but tricky to configure and use properly.

You also do want to know if the site has changed. If they redesigned the site and your crawler is broken your unit tests will still pass because they are running against a cached copy! You will need either another, smaller set of integration tests that are run infrequently against the live site or good logging and error detection in your crawling code that logs the exact issues, alerts you to the problem and stops crawling. Now you can update your cache, run your unit tests and see what you need to change.

Legal Issues

The law here can be slightly dangerous if you do stupid things. If the law gets involved you are dealing with people who regularly refer to wget and curl as "hacking tools". You don't want this.

The ethical reality of the situation is that there is no difference between using browser software to request a url and look at some data and using your own software to request a url and look at some data. Google is the largest scraping company in the world and they are loved for it. Identifying your bots name in the user agent and being open about the goals and intentions of your web crawler will help here as the law understands what Google is. If you are doing anything shady, like creating fake user accounts or accessing areas of the site that you shouldn't (either "blocked" by robots.txt or because of some kind of authorization exploit) then be aware that you are doing something unethical and the law's ignorance of technology will be extraordinarily dangerous here. It's a ridiculous situation but it's a real one.

It's literally possible to try and build a new search engine on the up and up as an upstanding citizen, make a mistake or have a bug in your software and be seen as a hacker. Not something you want considering the current political reality.

Who am I to write this giant wall of text anyway?

I've written a lot of web crawling related code in my life. I've been doing web related software development for more than a decade as a consultant, employee and startup founder. The early days were writing perl crawlers/scrapers and php websites. When we were embedding hidden iframes loading csv data into webpages to do ajax before Jesse James Garrett named it ajax, before XMLHTTPRequest was an idea. Before jQuery, before json. I'm in my mid-30's, that's apparently considered ancient for this business.

I've written large scale crawling/scraping systems twice, once for a large team at a media company (in Perl) and recently for a small team as the CTO of a search engine startup (in Python/Javascript). I currently work as a consultant, mostly coding in Clojure/Clojurescript (a wonderful expert language in general and has libraries that make crawler/scraper problems a delight)

I've written successful anti-crawling software systems as well. It's remarkably easy to write nigh-unscrapable sites if you want to or to identify and sabotage bots you don't like.

I like writing crawlers, scrapers and parsers more than any other type of software. It's challenging, fun and can be used to create amazing things.

Creating multiline strings in JavaScript

I like this syntax and indendation:

string = 'my long string...\n'
       + 'continue here\n'
       + 'and here.';

(but actually can't be considered as multiline string)

How do I capture all of my compiler's output to a file?

Assume you want to hilight warning and error from build ouput:

make |& grep -E "warning|error"

How to process images of a video, frame by frame, in video streaming using OpenCV and Python

The only solution I have found is not to set the index to a previous frame and wait (then OpenCV stops reading frames, anyway), but to initialize the capture one more time. So, it looks like this:

cap = cv2.VideoCapture(camera_url)
while True:
    ret, frame = cap.read()

    if not ret:
        cap = cv.VideoCapture(camera_url)
        continue

    # do your processing here

And it works perfectly!

How to hide a TemplateField column in a GridView

Am I missing something ?

If you can't set visibility on TemplateField then set it on its content

<asp:TemplateField>
  <ItemTemplate>
    <asp:LinkButton Visible='<%# MyBoolProperty %>' ID="foo" runat="server" ... />
  </ItemTemplate>
</asp:TemplateField> 

or if your content is complex then enclose it into a div and set visibility on the div

<asp:TemplateField>
  <ItemTemplate>
    <div runat="server" visible='<%# MyBoolProperty  %>' >
      <asp:LinkButton ID="attachmentButton" runat="server" ... />
    </div>
  </ItemTemplate>
</asp:TemplateField> 

Limit the height of a responsive image with css

The trick is to add both max-height: 100%; and max-width: 100%; to .container img. Example CSS:

.container {
  width: 300px;
  border: dashed blue 1px;
}

.container img {
  max-height: 100%;
  max-width: 100%;
}

In this way, you can vary the specified width of .container in whatever way you want (200px or 10% for example), and the image will be no larger than its natural dimensions. (You could specify pixels instead of 100% if you didn't want to rely on the natural size of the image.)

Here's the whole fiddle: http://jsfiddle.net/KatieK/Su28P/1/

Elasticsearch : Root mapping definition has unsupported parameters index : not_analyzed

Check your Elastic version.

I had these problem because I was looking at the incorrect version's documentation.

enter image description here

Java HTML Parsing

HTMLUnit might be of help. It does a lot more stuff too.

http://htmlunit.sourceforge.net/1

.NET data structures: ArrayList, List, HashTable, Dictionary, SortedList, SortedDictionary -- Speed, memory, and when to use each?

There are subtle and not-so-subtle differences between generic and non-generic collections. They merely use different underlying data structures. For example, Hashtable guarantees one-writer-many-readers without sync. Dictionary does not.

No restricted globals

Try adding window before location (i.e. window.location).

How can I delay a :hover effect in CSS?

For a more aesthetic appearance :) can be:

left:-9999em; 
top:-9999em; 

position for .sNv2 .nav UL can be replaced by z-index:-1 and z-index:1 for .sNv2 .nav LI:Hover UL

Ranges of floating point datatype in C?

The values for the float data type come from having 32 bits in total to represent the number which are allocated like this:

1 bit: sign bit

8 bits: exponent p

23 bits: mantissa

The exponent is stored as p + BIAS where the BIAS is 127, the mantissa has 23 bits and a 24th hidden bit that is assumed 1. This hidden bit is the most significant bit (MSB) of the mantissa and the exponent must be chosen so that it is 1.

This means that the smallest number you can represent is 01000000000000000000000000000000 which is 1x2^-126 = 1.17549435E-38.

The largest value is 011111111111111111111111111111111, the mantissa is 2 * (1 - 1/65536) and the exponent is 127 which gives (1 - 1 / 65536) * 2 ^ 128 = 3.40277175E38.

The same principles apply to double precision except the bits are:

1 bit: sign bit

11 bits: exponent bits

52 bits: mantissa bits

BIAS: 1023

So technically the limits come from the IEEE-754 standard for representing floating point numbers and the above is how those limits come about

Entity Framework 5 Updating a Record

I really like the accepted answer. I believe there is yet another way to approach this as well. Let's say you have a very short list of properties that you wouldn't want to ever include in a View, so when updating the entity, those would be omitted. Let's say that those two fields are Password and SSN.

db.Users.Attach(updatedUser);

var entry = db.Entry(updatedUser);
entry.State = EntityState.Modified;

entry.Property(e => e.Password).IsModified = false;
entry.Property(e => e.SSN).IsModified = false;   

db.SaveChanges();   

This example allows you to essentially leave your business logic alone after adding a new field to your Users table and to your View.

Set content of HTML <span> with Javascript

To do it without using a JavaScript library such as jQuery, you'd do it like this:

var span = document.getElementById("myspan"),
    text = document.createTextNode(''+intValue);
span.innerHTML = ''; // clear existing
span.appendChild(text);

If you do want to use jQuery, it's just this:

$("#myspan").text(''+intValue);

How can I include a YAML file inside another?

Probably it was not supported when question was asked but you can import other YAML file into one:

imports: [/your_location_to_yaml_file/Util.area.yaml]

Though I don't have any online reference but this works for me.

Ruby on Rails. How do I use the Active Record .build method in a :belongs to relationship?

Where it is documented:

From the API documentation under the has_many association in "Module ActiveRecord::Associations::ClassMethods"

collection.build(attributes = {}, …) Returns one or more new objects of the collection type that have been instantiated with attributes and linked to this object through a foreign key, but have not yet been saved. Note: This only works if an associated object already exists, not if it‘s nil!

The answer to building in the opposite direction is a slightly altered syntax. In your example with the dogs,

Class Dog
   has_many :tags
   belongs_to :person
end

Class Person
  has_many :dogs
end

d = Dog.new
d.build_person(:attributes => "go", :here => "like normal")

or even

t = Tag.new
t.build_dog(:name => "Rover", :breed => "Maltese")

You can also use create_dog to have it saved instantly (much like the corresponding "create" method you can call on the collection)

How is rails smart enough? It's magic (or more accurately, I just don't know, would love to find out!)

JPQL IN clause: Java-Arrays (or Lists, Sets...)?

I had a problem with this kind of sql, I was giving empty list in IN clause(always check the list if it is not empty). Maybe my practice will help somebody.

bash script use cut command at variable and store result at another variable

The awk solution is what I would use, but if you want to understand your problems with bash, here is a revised version of your script.

#!/bin/bash -vx

##config file with ip addresses like 10.10.10.1:80
file=config.txt

while read line ; do
  ##this line is not correct, should strip :port and store to ip var
  ip=$( echo "$line" |cut -d\: -f1 )
  ping $ip
done < ${file}

You could write your top line as

for line in $(cat $file) ; do ...

(but not recommended).

You needed command substitution $( ... ) to get the value assigned to $ip

reading lines from a file is usually considered more efficient with the while read line ... done < ${file} pattern.

I hope this helps.

Align div right in Bootstrap 3

i think you try to align the content to the right within the div, the div with offset already push itself to the right, here some code and LIVE sample:
FYI: .pull-right only push the div to the right, but not the content inside the div.

HTML:

<div class="row">
  <div class="container">
    <div class="col-md-4 someclass">
      left content
    </div>
    <div class="col-md-4 col-md-offset-4 someclass">
      <div class="yellow_background totheright">right content</div>
    </div>
  </div>
</div>

CSS:

.someclass{ /*this class for testing purpose only*/
    border:1px solid blue;
    line-height:2em;
}

.totheright{ /*this will align the text to the right*/
  text-align:right;
}

.yellow_background{
    background-color:yellow;
}

Another modification:

...
<div class="yellow_background totheright">
  <span>right content</span>
  <br/>image also align-right<br/>
  <img width="15%" src="https://www.google.com/images/srpr/logo11w.png"/>
</div>
...

hope it will clear your problem

Read file data without saving it in Flask

If you want to use standard Flask stuff - there's no way to avoid saving a temporary file if the uploaded file size is > 500kb. If it's smaller than 500kb - it will use "BytesIO", which stores the file content in memory, and if it's more than 500kb - it stores the contents in TemporaryFile() (as stated in the werkzeug documentation). In both cases your script will block until the entirety of uploaded file is received.

The easiest way to work around this that I have found is:

1) Create your own file-like IO class where you do all the processing of the incoming data

2) In your script, override Request class with your own:

class MyRequest( Request ):
  def _get_file_stream( self, total_content_length, content_type, filename=None, content_length=None ):
    return MyAwesomeIO( filename, 'w' )

3) Replace Flask's request_class with your own:

app.request_class = MyRequest

4) Go have some beer :)

How to redirect output of an entire shell script within the script itself?

Addressing the question as updated.

#...part of script without redirection...

{
    #...part of script with redirection...
} > file1 2>file2 # ...and others as appropriate...

#...residue of script without redirection...

The braces '{ ... }' provide a unit of I/O redirection. The braces must appear where a command could appear - simplistically, at the start of a line or after a semi-colon. (Yes, that can be made more precise; if you want to quibble, let me know.)

You are right that you can preserve the original stdout and stderr with the redirections you showed, but it is usually simpler for the people who have to maintain the script later to understand what's going on if you scope the redirected code as shown above.

The relevant sections of the Bash manual are Grouping Commands and I/O Redirection. The relevant sections of the POSIX shell specification are Compound Commands and I/O Redirection. Bash has some extra notations, but is otherwise similar to the POSIX shell specification.

Javascript - Track mouse position

I don't have enough reputation to post a comment reply, but took TJ Crowder's excellent answer and fully defined the code on a 100ms timer. (He left some details to the imagination.)

Thanks OP for the question, and TJ for the answer! You're both a great help. Code is embedded below as a mirror of isbin.

_x000D_
_x000D_
<!DOCTYPE html>_x000D_
<html>_x000D_
<head>_x000D_
  <meta charset="utf-8">_x000D_
  <title>Example</title>_x000D_
  <style>_x000D_
    body {_x000D_
      height: 3000px;_x000D_
    }_x000D_
    .dot {_x000D_
      width: 2px;_x000D_
      height: 2px;_x000D_
      background-color: black;_x000D_
      position: absolute;_x000D_
    }_x000D_
  </style>_x000D_
</head>_x000D_
<body>_x000D_
<script>_x000D_
(function() {_x000D_
    "use strict";_x000D_
    var mousePos;_x000D_
_x000D_
    document.onmousemove = handleMouseMove;_x000D_
    setInterval(getMousePosition, 100); // setInterval repeats every X ms_x000D_
_x000D_
    function handleMouseMove(event) {_x000D_
        var eventDoc, doc, body;_x000D_
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        event = event || window.event; // IE-ism_x000D_
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        // If pageX/Y aren't available and clientX/Y are,_x000D_
        // calculate pageX/Y - logic taken from jQuery._x000D_
        // (This is to support old IE)_x000D_
        if (event.pageX == null && event.clientX != null) {_x000D_
            eventDoc = (event.target && event.target.ownerDocument) || document;_x000D_
            doc = eventDoc.documentElement;_x000D_
            body = eventDoc.body;_x000D_
_x000D_
            event.pageX = event.clientX +_x000D_
              (doc && doc.scrollLeft || body && body.scrollLeft || 0) -_x000D_
              (doc && doc.clientLeft || body && body.clientLeft || 0);_x000D_
            event.pageY = event.clientY +_x000D_
              (doc && doc.scrollTop  || body && body.scrollTop  || 0) -_x000D_
              (doc && doc.clientTop  || body && body.clientTop  || 0 );_x000D_
        }_x000D_
_x000D_
        mousePos = {_x000D_
            x: event.pageX,_x000D_
            y: event.pageY_x000D_
        };_x000D_
    }_x000D_
    function getMousePosition() {_x000D_
        var pos = mousePos;_x000D_
  _x000D_
        if (!pos) {_x000D_
            // We haven't seen any movement yet, so don't add a duplicate dot _x000D_
        }_x000D_
        else {_x000D_
            // Use pos.x and pos.y_x000D_
            // Add a dot to follow the cursor_x000D_
            var dot;_x000D_
            dot = document.createElement('div');_x000D_
            dot.className = "dot";_x000D_
            dot.style.left = pos.x + "px";_x000D_
            dot.style.top = pos.y + "px";_x000D_
            document.body.appendChild(dot);_x000D_
        }_x000D_
    }_x000D_
})();_x000D_
</script>_x000D_
</body>_x000D_
</html>
_x000D_
_x000D_
_x000D_

How to hide scrollbar in Firefox?

For more recent version of Firefox the old solutions don't work anymore, but I did succesfully used in v66.0.3 the scrollbar-color property which you can set to transparent transparent and which will make the scrollbar in Firefox on the desktop at least invisible (still takes place in the viewport and on mobile doesn't work, but there the scrollbar is a fine line that is placed over the content on the right).

overflow-y: auto; //or hidden if you don't want horizontal scrolling
overflow-y: auto;
scrollbar-color: transparent transparent;

Passing a variable from one php include file to another: global vs. not

Here is a pitfall to avoid. In case you need to access your variable $name within a function, you need to say "global $name;" at the beginning of that function. You need to repeat this for each function in the same file.

include('front.inc');
global $name;

function foo() {
  echo $name;
}

function bar() {
  echo $name;
}

foo();
bar();

will only show errors. The correct way to do that would be:

include('front.inc');

function foo() {
  global $name;
  echo $name;
}

function bar() {
  global $name;
  echo $name;
}

foo();
bar();

Select records from today, this week, this month php mysql

To get last week's data in MySQL. This works for me even across the year boundries.

select * from orders_order where YEARWEEK(my_date_field)= YEARWEEK(DATE_SUB(CURRENT_DATE(), INTERVAL 1 WEEK));

To get current week's data

select * from orders_order where YEARWEEK(date_sold)= YEARWEEK(CURRENT_DATE());

How do I request and process JSON with python?

For anything with requests to URLs you might want to check out requests. For JSON in particular:

>>> import requests
>>> r = requests.get('https://github.com/timeline.json')
>>> r.json()
[{u'repository': {u'open_issues': 0, u'url': 'https://github.com/...

How do you check that a number is NaN in JavaScript?

I've created this little function that works like a charm. Instead of checking for NaN which seems to be counter intuitive, you check for a number. I'm pretty sure I am not the first to do it this way, but I thought i'd share.

function isNum(val){
    var absVal = Math.abs(val);
    var retval = false;
    if((absVal-absVal) == 0){
        retval = true
    }

    return retval;
}

Deleting Row in SQLite in Android

The only way that worked for me was this

fun removeCart(mCart: Cart) {
    val db = dbHelper.writableDatabase
    val deleteLineWithThisValue = mCart.f
    db.delete(cons.tableNames[3], Cart.KEY_f + "  LIKE  '%" + deleteLineWithThisValue + "%' ", null)
}


class Cart {
    var a: String? = null
    var b: String? = null
    var c: String? = null
    var d: String? = null
    var e: Int? = null
    var f: String? = null

companion object {
    // Labels Table Columns names
    const val rowIdKey = "_id"
    const val idKey = "id"
    const val KEY_a = "a"
    const val KEY_b = "b"
    const val KEY_c = "c"
    const val KEY_d = "d"
    const val KEY_e = "e"
    const val KEY_f = "f"
   }
}

object cons {
    val tableNames = arrayOf(
            /*0*/ "shoes",
            /*1*/ "hats",
            /*2*/ "shirt",
            /*3*/ "car"
         )
 }

How to concat a string to xsl:value-of select="...?

Use:

<a href="wantedText{/*/properties/property[@name='report']/@value)}"></a>

Replace Div Content onclick

A simple addClass and removeClass will do the trick on what you need..

$('#change').on('click', function() { 
  $('div').each(function() { 
    if($(this).hasClass('active')) { 
        $(this).removeClass('active');
    } else { 
        $(this).addClass('active');
    }
});

});

Seee fiddle

I recommend you to learn jquery first before using.

Initialize 2D array

Easy to read/type.

  table = new char[][] {
      "0123456789".toCharArray()
    , "abcdefghij".toCharArray()
  };

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

You should use Java's built in serialization mechanism. To use it, you need to do the following:

  1. Declare the Club class as implementing Serializable:

    public class Club implements Serializable {
        ...
    }
    

    This tells the JVM that the class can be serialized to a stream. You don't have to implement any method, since this is a marker interface.

  2. To write your list to a file do the following:

    FileOutputStream fos = new FileOutputStream("t.tmp");
    ObjectOutputStream oos = new ObjectOutputStream(fos);
    oos.writeObject(clubs);
    oos.close();
    
  3. To read the list from a file, do the following:

    FileInputStream fis = new FileInputStream("t.tmp");
    ObjectInputStream ois = new ObjectInputStream(fis);
    List<Club> clubs = (List<Club>) ois.readObject();
    ois.close();
    

Difference between PCDATA and CDATA in DTD

PCDATA - Parsed Character Data

XML parsers normally parse all the text in an XML document.

CDATA - (Unparsed) Character Data

The term CDATA is used about text data that should not be parsed by the XML parser.

Characters like "<" and "&" are illegal in XML elements.

typescript - cloning object

Add "lodash.clonedeep": "^4.5.0" to your package.json. Then use like this:

import * as _ from 'lodash';

...

const copy = _.cloneDeep(original)

How can I check if a string is null or empty in PowerShell?

I have a PowerShell script I have to run on a computer so out of date that it doesn't have [String]::IsNullOrWhiteSpace(), so I wrote my own.

function IsNullOrWhitespace($str)
{
    if ($str)
    {
        return ($str -replace " ","" -replace "`t","").Length -eq 0
    }
    else
    {
        return $TRUE
    }
}

How to initialize a dict with keys from a list and empty value in Python?

>>> keyDict = {"a","b","c","d"}

>>> dict([(key, []) for key in keyDict])

Output:

{'a': [], 'c': [], 'b': [], 'd': []}

Android statusbar icons color

Yes it's possible to change it to gray (no custom colors) but this only works from API 23 and above you only need to add this in your values-v23/styles.xml

<item name="android:windowLightStatusBar">true</item>

enter image description here

How to check if the URL contains a given string?

Try this:

<script type="text/javascript">             
    $(document).ready
    (
        function () 
        { 
            var regExp = /franky/g;
            var testString = "something.com/frankyssssddsdfjsdflk?franky";//Inyour case it would be window.location;
            if(regExp.test(testString)) // This doesn't work, any suggestions.                 
            {                      
                alert("your url contains the name franky");                 
            }             
        }
    );         
</script>