Programs & Examples On #Http method

HTTP methods used to designate the appropriate action to direct a server towards a resource. GET and POST are the most widely known; PATCH and DELETE also fit in that category, among others.

curl -GET and -X GET

The use of -X [WHATEVER] merely changes the request's method string used in the HTTP request. This is easier to understand with two examples — one with -X [WHATEVER] and one without — and the associated HTTP request headers for each:

# curl -XPANTS -o nul -v http://neverssl.com/
* Connected to neverssl.com (13.224.86.126) port 80 (#0)
> PANTS / HTTP/1.1
> Host: neverssl.com
> User-Agent: curl/7.42.0
> Accept: */*

# curl -o nul -v http://neverssl.com/
* Connected to neverssl.com (13.33.50.167) port 80 (#0)
> GET / HTTP/1.1
> Host: neverssl.com
> User-Agent: curl/7.42.0
> Accept: */*

Should I use PATCH or PUT in my REST API?

The R in REST stands for resource

(Which isn't true, because it stands for Representational, but it's a good trick to remember the importance of Resources in REST).

About PUT /groups/api/v1/groups/{group id}/status/activate: you are not updating an "activate". An "activate" is not a thing, it's a verb. Verbs are never good resources. A rule of thumb: if the action, a verb, is in the URL, it probably is not RESTful.

What are you doing instead? Either you are "adding", "removing" or "updating" an activation on a Group, or if you prefer: manipulating a "status"-resource on a Group. Personally, I'd use "activations" because they are less ambiguous than the concept "status": creating a status is ambiguous, creating an activation is not.

  • POST /groups/{group id}/activation Creates (or requests the creation of) an activation.
  • PATCH /groups/{group id}/activation Updates some details of an existing activation. Since a group has only one activation, we know what activation-resource we are referring to.
  • PUT /groups/{group id}/activation Inserts-or-replaces the old activation. Since a group has only one activation, we know what activation-resource we are referring to.
  • DELETE /groups/{group id}/activation Will cancel, or remove the activation.

This pattern is useful when the "activation" of a Group has side-effects, such as payments being made, mails being sent and so on. Only POST and PATCH may have such side-effects. When e.g. a deletion of an activation needs to, say, notify users over mail, DELETE is not the right choice; in that case you probably want to create a deactivation resource: POST /groups/{group_id}/deactivation.

It is a good idea to follow these guidelines, because this standard contract makes it very clear for your clients, and all the proxies and layers between the client and you, know when it is safe to retry, and when not. Let's say the client is somewhere with flaky wifi, and its user clicks on "deactivate", which triggers a DELETE: If that fails, the client can simply retry, until it gets a 404, 200 or anything else it can handle. But if it triggers a POST to deactivation it knows not to retry: the POST implies this.
Any client now has a contract, which, when followed, will protect against sending out 42 emails "your group has been deactivated", simply because its HTTP-library kept retrying the call to the backend.

Updating a single attribute: use PATCH

PATCH /groups/{group id}

In case you wish to update an attribute. E.g. the "status" could be an attribute on Groups that can be set. An attribute such as "status" is often a good candidate to limit to a whitelist of values. Examples use some undefined JSON-scheme:

PATCH /groups/{group id} { "attributes": { "status": "active" } }
response: 200 OK

PATCH /groups/{group id} { "attributes": { "status": "deleted" } }
response: 406 Not Acceptable

Replacing the resource, without side-effects use PUT.

PUT /groups/{group id}

In case you wish to replace an entire Group. This does not necessarily mean that the server actually creates a new group and throws the old one out, e.g. the ids might remain the same. But for the clients, this is what PUT can mean: the client should assume he gets an entirely new item, based on the server's response.

The client should, in case of a PUT request, always send the entire resource, having all the data that is needed to create a new item: usually the same data as a POST-create would require.

PUT /groups/{group id} { "attributes": { "status": "active" } }
response: 406 Not Acceptable

PUT /groups/{group id} { "attributes": { "name": .... etc. "status": "active" } }
response: 201 Created or 200 OK, depending on whether we made a new one.

A very important requirement is that PUT is idempotent: if you require side-effects when updating a Group (or changing an activation), you should use PATCH. So, when the update results in e.g. sending out a mail, don't use PUT.

Use of PUT vs PATCH methods in REST API real life scenarios

One additional information I just one to add is that a PATCH request use less bandwidth compared to a PUT request since just a part of the data is sent not the whole entity. So just use a PATCH request for updates of specific records like (1-3 records) while PUT request for updating a larger amount of data. That is it, don't think too much or worry about it too much.

What is the difference between POST and GET?

POST and GET are two HTTP request methods. GET is usually intended to retrieve some data, and is expected to be idempotent (repeating the query does not have any side-effects) and can only send limited amounts of parameter data to the server. GET requests are often cached by default by some browsers if you are not careful.

POST is intended for changing the server state. It carries more data, and repeating the query is allowed (and often expected) to have side-effects such as creating two messages instead of one.

Which HTTP methods match up to which CRUD methods?

Generally speaking, this is the pattern I use:

  • HTTP GET - SELECT/Request
  • HTTP PUT - UPDATE
  • HTTP POST - INSERT/Create
  • HTTP DELETE - DELETE

When should I use GET or POST method? What's the difference between them?

You should use POST if there is a lot of data, or sort-of sensitive information (really sensitive stuff needs a secure connection as well).

Use GET if you want people to be able to bookmark your page, because all the data is included with the bookmark.

Just be careful of people hitting REFRESH with the GET method, because the data will be sent again every time without warning the user (POST sometimes warns the user about resending data).

Powershell Invoke-WebRequest Fails with SSL/TLS Secure Channel

In a shameless attempt to steal some votes, SecurityProtocol is an Enum with the [Flags] attribute. So you can do this:

[Net.ServicePointManager]::SecurityProtocol = 
  [Net.SecurityProtocolType]::Tls12 -bor `
  [Net.SecurityProtocolType]::Tls11 -bor `
  [Net.SecurityProtocolType]::Tls

Or since this is PowerShell, you can let it parse a string for you:

[Net.ServicePointManager]::SecurityProtocol = "tls12, tls11, tls"

Then you don't technically need to know the TLS version.

I copied and pasted this from a script I created after reading this answer because I didn't want to cycle through all the available protocols to find one that worked. Of course, you could do that if you wanted to.

Final note - I have the original (minus SO edits) statement in my PowerShell profile so it's in every session I start now. It's not totally foolproof since there are still some sites that just fail but I surely see the message in question much less frequently.

Map enum in JPA with fixed values?

Possibly close related code of Pascal

@Entity
@Table(name = "AUTHORITY_")
public class Authority implements Serializable {

    public enum Right {
        READ(100), WRITE(200), EDITOR(300);

        private Integer value;

        private Right(Integer value) {
            this.value = value;
        }

        // Reverse lookup Right for getting a Key from it's values
        private static final Map<Integer, Right> lookup = new HashMap<Integer, Right>();
        static {
            for (Right item : Right.values())
                lookup.put(item.getValue(), item);
        }

        public Integer getValue() {
            return value;
        }

        public static Right getKey(Integer value) {
            return lookup.get(value);
        }

    };

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "AUTHORITY_ID")
    private Long id;

    @Column(name = "RIGHT_ID")
    private Integer rightId;

    public Right getRight() {
        return Right.getKey(this.rightId);
    }

    public void setRight(Right right) {
        this.rightId = right.getValue();
    }

}

Read Post Data submitted to ASP.Net Form

NameValueCollection nvclc = Request.Form;
string   uName= nvclc ["txtUserName"];
string   pswod= nvclc ["txtPassword"];
//try login
CheckLogin(uName, pswod);

Force “landscape” orientation mode

I had the same problem, it was a missing manifest.json file, if not found the browser decide with orientation is best fit, if you don't specify the file or use a wrong path.

I fixed just calling the manifest.json correctly on html headers.

My html headers:

<meta name="application-name" content="App Name">
<meta name="mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-capable" content="yes" />
<meta name="apple-mobile-web-app-status-bar-style" content="black" />
<link rel="manifest" href="manifest.json">
<meta name="msapplication-starturl" content="/">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<meta name="theme-color" content="#">
<meta name="msapplication-TileColor" content="#">
<meta name="msapplication-config" content="browserconfig.xml">
<link rel="icon" type="image/png" sizes="192x192" href="android-chrome-192x192.png">
<link rel="apple-touch-icon" sizes="180x180" href="apple-touch-icon.png">
<link rel="mask-icon" href="safari-pinned-tab.svg" color="#ffffff">
<link rel="shortcut icon" href="favicon.ico">

And the manifest.json file content:

{
  "display": "standalone",
  "orientation": "portrait",
  "start_url": "/",
  "theme_color": "#000000",
  "background_color": "#ffffff",
  "icons": [
  {
    "src": "android-chrome-192x192.png",
    "sizes": "192x192",
    "type": "image/png"
  }
}

To generate your favicons and icons use this webtool: https://realfavicongenerator.net/

To generate your manifest file use: https://tomitm.github.io/appmanifest/

My PWA Works great, hope it helps!

How to instantiate, initialize and populate an array in TypeScript?

A simple solution could be:

interface bar {
    length: number;
}

let bars: bar[];
bars = [];

Convert JS date time to MySQL datetime

A simple solution is send a timestamp to MySQL and let it do the conversion. Javascript uses timestamps in milliseconds whereas MySQL expects them to be in seconds - so a division by 1000 is needed:

// Current date / time as a timestamp:
let jsTimestamp = Date.now();

// **OR** a specific date / time as a timestamp:
jsTimestamp = new Date("2020-11-17 16:34:59").getTime();

// Adding 30 minutes (to answer the second part of the question):
jsTimestamp += 30 * 1000;

// Example query converting Javascript timestamp into a MySQL date
let sql = 'SELECT FROM_UNIXTIME(' + jsTimestamp + ' / 1000) AS mysql_date_time';

How can I use String substring in Swift 4? 'substring(to:)' is deprecated: Please use String slicing subscript with a 'partial range from' operator

Some useful extensions:

extension String {
    func substring(from: Int, to: Int) -> String {
        let start = index(startIndex, offsetBy: from)
        let end = index(start, offsetBy: to - from)
        return String(self[start ..< end])
    }

    func substring(range: NSRange) -> String {
        return substring(from: range.lowerBound, to: range.upperBound)
    }
}

How to sort Counter by value? - python

More general sorted, where the key keyword defines the sorting method, minus before numerical type indicates descending:

>>> x = Counter({'a':5, 'b':3, 'c':7})
>>> sorted(x.items(), key=lambda k: -k[1])  # Ascending
[('c', 7), ('a', 5), ('b', 3)]

Implement touch using Python?

This answer is compatible with all versions since Python-2.5 when keyword with has been released.

1. Create file if does not exist + Set current time
(exactly same as command touch)

import os

fname = 'directory/filename.txt'
with open(fname, 'a'):     # Create file if does not exist
    os.utime(fname, None)  # Set access/modified times to now
                           # May raise OSError if file does not exist

A more robust version:

import os

with open(fname, 'a'):
  try:                     # Whatever if file was already existing
    os.utime(fname, None)  # => Set current time anyway
  except OSError:
    pass  # File deleted between open() and os.utime() calls

2. Just create the file if does not exist
(does not update time)

with open(fname, 'a'):  # Create file if does not exist
    pass

3. Just update file access/modified times
(does not create file if not existing)

import os

try:
    os.utime(fname, None)  # Set access/modified times to now
except OSError:
    pass  # File does not exist (or no permission)

Using os.path.exists() does not simplify the code:

from __future__ import (absolute_import, division, print_function)
import os

if os.path.exists(fname):
  try:
    os.utime(fname, None)  # Set access/modified times to now
  except OSError:
    pass  # File deleted between exists() and utime() calls
          # (or no permission)

Bonus: Update time of all files in a directory

from __future__ import (absolute_import, division, print_function)
import os

number_of_files = 0

#   Current directory which is "walked through"
#   |     Directories in root
#   |     |  Files in root       Working directory
#   |     |  |                     |
for root, _, filenames in os.walk('.'):
  for fname in filenames:
    pathname = os.path.join(root, fname)
    try:
      os.utime(pathname, None)  # Set access/modified times to now
      number_of_files += 1
    except OSError as why:
      print('Cannot change time of %r because %r', pathname, why)

print('Changed time of %i files', number_of_files)

Apply CSS rules if browser is IE

A good way to avoid loading multiple CSS files or to have inline CSS is to hand a class to the body tag depending on the version of Internet Explorer. If you only need general IE hacks, you can do something like this, but it can be extended to be version specific:

<!--[if IE ]><body class="ie"><![endif]-->
<!--[if !IE]>--><body><!--<![endif]-->

Now in your css code, you can simply do:

.ie .abc {
  position:absolute;
  left:30;
  top:-10;
}

This also keeps your CSS files valid, as you do not have to use dirty (and invalid) CSS hacks.

How to convert string to datetime format in pandas python?

Approach: 1

Given original string format: 2019/03/04 00:08:48

you can use

updated_df = df['timestamp'].astype('datetime64[ns]')

The result will be in this datetime format: 2019-03-04 00:08:48

Approach: 2

updated_df = df.astype({'timestamp':'datetime64[ns]'})

window.location.href and window.open () methods in JavaScript

window.location.href is not a method, it's a property that will tell you the current URL location of the browser. Changing the value of the property will redirect the page.

window.open() is a method that you can pass a URL to that you want to open in a new window. For example:

window.location.href example:

window.location.href = 'http://www.google.com'; //Will take you to Google.

window.open() example:

window.open('http://www.google.com'); //This will open Google in a new window.

Additional Information:

window.open() can be passed additional parameters. See: window.open tutorial

How do I run .sh or .bat files from Terminal?

Drag-And-Drop

Easiest way for a lazy Mac user like me: Drag-and-drop the startup.sh file from the Finder to the Terminal window and press Return.

To shutdown Tomcat, do the same with shutdown.sh.

You can delete all the .bat files as they are only for a Windows PC, of no use on a Mac to other Unix computer. I delete them as it makes it easier to read that folder's listing.

File Permissions

I find that a fresh Tomcat download will not run on my Mac because of file permission restrictions throwing errors during startup. I use the BatChmod app which wraps a GUI around the equivelant Unix commands to reset file permissions.

Port-Forwarding

Unix systems protect access to ports numbered under 1024. So if you want to use port 80 with Tomcat you will need to learn how to do "port-forwarding" to forward incoming requests to port 8080 where Tomcat listens by default. To do port-forwarding, you issue commands to the packet-filtering (firewall) app built into Mac OS X (and BSD). In the old days we used ipfw. In Mac OS X 10.7 (Lion) and later Apple is moving to a newer tool, pf.

Test if object implements interface

For the instance:

if (obj is IMyInterface) {}

For the class:

Check if typeof(MyClass).GetInterfaces() contains the interface.

Difference between .on('click') vs .click()

As mentioned by the other answers:

$("#whatever").click(function(){ });
// is just a shortcut for
$("#whatever").on("click", function(){ })

Noting though that .on() supports several other parameter combinations that .click() doesn't, allowing it to handle event delegation (superceding .delegate() and .live()).

(And obviously there are other similar shortcut methods for "keyup", "focus", etc.)

The reason I'm posting an extra answer is to mention what happens if you call .click() with no parameters:

$("#whatever").click();
// is a shortcut for
$("#whatever").trigger("click");

Noting that if you use .trigger() directly you can also pass extra parameters or a jQuery event object, which you can't do with .click().

I also wanted to mention that if you look at the jQuery source code (in jquery-1.7.1.js) you'll see that internally the .click() (or .keyup(), etc.) function will actually call .on() or .trigger(). Obviously this means you can be assured that they really do have the same result, but it also means that using .click() has a tiny bit more overhead - not anything to worry or even think about in most circumstances, but theoretically it might matter in extraordinary circumstances.

EDIT: Finally, note that .on() allows you to bind several events to the same function in one line, e.g.:

$("#whatever").on("click keypress focus", function(){});

Convert to/from DateTime and Time in Ruby

As an update to the state of the Ruby ecosystem, Date, DateTime and Time now have methods to convert between the various classes. Using Ruby 1.9.2+:

pry
[1] pry(main)> ts = 'Jan 1, 2000 12:01:01'
=> "Jan 1, 2000 12:01:01"
[2] pry(main)> require 'time'
=> true
[3] pry(main)> require 'date'
=> true
[4] pry(main)> ds = Date.parse(ts)
=> #<Date: 2000-01-01 (4903089/2,0,2299161)>
[5] pry(main)> ds.to_date
=> #<Date: 2000-01-01 (4903089/2,0,2299161)>
[6] pry(main)> ds.to_datetime
=> #<DateTime: 2000-01-01T00:00:00+00:00 (4903089/2,0,2299161)>
[7] pry(main)> ds.to_time
=> 2000-01-01 00:00:00 -0700
[8] pry(main)> ds.to_time.class
=> Time
[9] pry(main)> ds.to_datetime.class
=> DateTime
[10] pry(main)> ts = Time.parse(ts)
=> 2000-01-01 12:01:01 -0700
[11] pry(main)> ts.class
=> Time
[12] pry(main)> ts.to_date
=> #<Date: 2000-01-01 (4903089/2,0,2299161)>
[13] pry(main)> ts.to_date.class
=> Date
[14] pry(main)> ts.to_datetime
=> #<DateTime: 2000-01-01T12:01:01-07:00 (211813513261/86400,-7/24,2299161)>
[15] pry(main)> ts.to_datetime.class
=> DateTime

How do I find out which DOM element has the focus?

With dojo, you can use dijit.getFocus()

XML Serialize generic list of serializable objects

Below is a Util class in my project:

namespace Utils
{
    public static class SerializeUtil
    {
        public static void SerializeToFormatter<F>(object obj, string path) where F : IFormatter, new()
        {
            if (obj == null)
            {
                throw new NullReferenceException("obj Cannot be Null.");
            }

            if (obj.GetType().IsSerializable == false)
            {
                //  throw new 
            }
            IFormatter f = new F();
            SerializeToFormatter(obj, path, f);
        }

        public static T DeserializeFromFormatter<T, F>(string path) where F : IFormatter, new()
        {
            T t;
            IFormatter f = new F();
            using (FileStream fs = File.OpenRead(path))
            {
                t = (T)f.Deserialize(fs);
            }
            return t;
        }

        public static void SerializeToXML<T>(string path, object obj)
        {
            XmlSerializer xs = new XmlSerializer(typeof(T));
            using (FileStream fs = File.Create(path))
            {
                xs.Serialize(fs, obj);
            }
        }

        public static T DeserializeFromXML<T>(string path)
        {
            XmlSerializer xs = new XmlSerializer(typeof(T));
            using (FileStream fs = File.OpenRead(path))
            {
                return (T)xs.Deserialize(fs);
            }
        }

        public static T DeserializeFromXml<T>(string xml)
        {
            T result;

            var ser = new XmlSerializer(typeof(T));
            using (var tr = new StringReader(xml))
            {
                result = (T)ser.Deserialize(tr);
            }
            return result;
        }


        private static void SerializeToFormatter(object obj, string path, IFormatter formatter)
        {
            using (FileStream fs = File.Create(path))
            {
                formatter.Serialize(fs, obj);
            }
        }
    }
}

Regex date validation for yyyy-mm-dd

This will match yyyy-mm-dd and also yyyy-m-d:

^\d{4}\-(0?[1-9]|1[012])\-(0?[1-9]|[12][0-9]|3[01])$

Regular expression visualization

If you're looking for an exact match for yyyy-mm-dd then try this

^\d{4}\-(0[1-9]|1[012])\-(0[1-9]|[12][0-9]|3[01])$

or use this one if you need to find a date inside a string like The date is 2017-11-30

\d{4}\-(0?[1-9]|1[012])\-(0?[1-9]|[12][0-9]|3[01])*

https://regex101.com/r/acvpss/1

Fast ceiling of an integer division in C / C++

Compile with O3, The compiler performs optimization well.

q = x / y;
if (x % y)  ++q;

How to specify a editor to open crontab file? "export EDITOR=vi" does not work

To quote the man:

The -e option is used to edit the current crontab using the editor specified by the VISUAL or EDITOR environment variables

Most often if you run crontab -e from X, you have VISUAL set; that's what is used. Try this:

VISUAL=vi crontab -e

It just worked for me :)

Location of WSDL.exe

If you have Windows 10 and VS2019, and the .NET Framework 4.8, below you can see the Location of WSDL.exe

Path in your pc C:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.8 Tools

How can I display just a portion of an image in HTML/CSS?

adjust the background-position to move background images in different positions of the div

div { 
       background-image: url('image url')
       background-position: 0 -250px; 
    }

Is there a cross-domain iframe height auto-resizer that works?

Here is an alternative implementation.

enter image description here

Basically if you able to edit page at other domain you can place another iframe page that belongs to your server which saving height to cookies. With an interval read cookies when it is updated, update the height of the iframe. That is all.

Edit: 2019 December

The solution above basically uses another iframe inside of an iframe 3rd iframe is belongs to the top page domain, which you call this page with a query string that saves size value to a cookie, outer page checks this query with some interval. But it is not a good solution so you should follow this one:

In Top page :

window.addEventListener("message", (m)=>{iframeResizingFunction(m)});

Here you can check m.origin to see where is it comes from.

In frame page:

window.parent.postMessage({ width: 640, height:480 }, "*")

Although, please don't forget this is not so secure way. To make it secure update * value (targetOrigin) with your desired value. Please follow documentation: https://developer.mozilla.org/en-US/docs/Web/API/Window/postMessage

how to use getSharedPreferences in android

First get the instance of SharedPreferences using

SharedPreferences userDetails = context.getSharedPreferences("userdetails", MODE_PRIVATE);

Now to save the values in the SharedPreferences

Editor edit = userDetails.edit();
edit.putString("username", username.getText().toString().trim());
edit.putString("password", password.getText().toString().trim());
edit.apply();

Above lines will write username and password to preference

Now to to retrieve saved values from preference, you can follow below lines of code

String userName = userDetails.getString("username", "");
String password = userDetails.getString("password", "");

(NOTE: SAVING PASSWORD IN THE APP IS NOT RECOMMENDED. YOU SHOULD EITHER ENCRYPT THE PASSWORD BEFORE SAVING OR SKIP THE SAVING THE PASSWORD)

Is it possible to embed animated GIFs in PDFs?

Maybe use LaTeX and try something like this

\documentclass[a4paper]{article}
\usepackage[3D]{movie15}
\usepackage{hyperref}
\begin{document}
\includemovie[
    poster,
    toolbar, 
    3Daac=60.000000, 3Droll=0.000000, 3Dc2c=0.000000 2.483000 0.000000,     3Droo=2.483000, 3Dcoo=0.000000 0.000000 0.000000,
    3Dlights=CAD,
]{\linewidth}{\linewidth}{Bob.u3d}
\end{document}

where Bob3d.u3d is a sample virtual reality file I had. This works (or did) for movies, and I expect it might work for gifs too.

Getting title and meta tags from external website

Improved answer from @shamittomar above to get the meta tags (or the specified one from html source)

Can be improved further... the difference from php's default get_meta_tags is that it works even when there is unicode string

function getMetaTags($html, $name = null)
{
    $doc = new DOMDocument();
    try {
        @$doc->loadHTML($html);
    } catch (Exception $e) {

    }

    $metas = $doc->getElementsByTagName('meta');

    $data = [];
    for ($i = 0; $i < $metas->length; $i++)
    {
        $meta = $metas->item($i);

        if (!empty($meta->getAttribute('name'))) {
            // will ignore repeating meta tags !!
            $data[$meta->getAttribute('name')] = $meta->getAttribute('content');
        }
    }

    if (!empty($name)) {
        return !empty($data[$name]) ? $data[$name] : false;
    }

    return $data;
}

Capture iOS Simulator video for App Preview

This is the way I found easiest and you only need one iPhone and iPad:

Record device screen with QuickTime Player:

  • Connect your device.
  • Open QuickTime Player.
  • Choose File > New Movie Recording (CMD + alt + N)
  • In the window that appears, select your iOS device as the camera with maximum resolution.
  • Save video file (CMD + S)

Open iMovie

  • Select File -> New App Preview
  • Drag an IMAGE from your app with the biggest resolution ex. a 1920 x 1080 screenshot to the project. (This makes the video 1920 x 1080 even if you recorded with a iPhone 5)
  • Drag the movie you recorded to the project.
  • Save by choosing File -> Share -> App Preview

Now do this with all of your devices or:

Download Handbreak: https://handbrake.fr/downloads.php

And resize the high res video:

  • Drag your high res video to Handbreak
  • Select "Picture Settings" icon
  • Resize to the correct size - close and press "Start" icon - gets saved to desktop

Remove element by id

I know that augmenting native DOM functions isn't always the best or most popular solution, but this works fine for modern browsers.

Element.prototype.remove = function() {
    this.parentElement.removeChild(this);
}
NodeList.prototype.remove = HTMLCollection.prototype.remove = function() {
    for(var i = this.length - 1; i >= 0; i--) {
        if(this[i] && this[i].parentElement) {
            this[i].parentElement.removeChild(this[i]);
        }
    }
}

And then you can remove elements like this

document.getElementById("my-element").remove();

or

document.getElementsByClassName("my-elements").remove();

Note: this solution doesn't work for IE 7 and below. For more info about extending the DOM read this article.

EDIT: Reviewing my answer in 2019, node.remove() has come to the rescue and can be used as follows (without the polyfill above):

document.getElementById("my-element").remove();

or

[...document.getElementsByClassName("my-elements")].map(n => n && n.remove());

These functions are available in all modern browsers (not IE). Read more on MDN.

Escape double quote in grep

The problem is that you aren't correctly escaping the input string, try:

echo "\"member\":\"time\"" | grep -e "member\""

Alternatively, you can use unescaped double quotes within single quotes:

echo '"member":"time"' | grep -e 'member"'

It's a matter of preference which you find clearer, although the second approach prevents you from nesting your command within another set of single quotes (e.g. ssh 'cmd').

SQL datetime format to date only

if you are using SQL Server use convert

e.g. select convert(varchar(10), DeliveryDate, 103) as ShortDate

more information here: http://msdn.microsoft.com/en-us/library/aa226054(v=sql.80).aspx

Auto-Submit Form using JavaScript

This solution worked for me:

<body onload="setTimeout(function() { document.myform.submit() }, 5000)">
   <form action=TripRecorder name="myform">
      <textarea id="result1"  name="res1" value="str1" cols="20" rows="1" ></textarea> <br> <br/>
      <textarea id="result2" name="res2" value="str2" cols="20" rows="1" ></textarea>
   </form>
</body>

Access nested dictionary items via a list of keys?

You can use pydash:

import pydash as _

_.get(dataDict, ["b", "v", "y"], default='Default')

https://pydash.readthedocs.io/en/latest/api.html

Passing the argument to CMAKE via command prompt

CMake 3.13 on Ubuntu 16.04

This approach is more flexible because it doesn't constraint MY_VARIABLE to a type:

$ cat CMakeLists.txt 
message("MY_VARIABLE=${MY_VARIABLE}")
if( MY_VARIABLE ) 
    message("MY_VARIABLE evaluates to True")
endif()

$ mkdir build && cd build

$ cmake ..
MY_VARIABLE=
-- Configuring done
-- Generating done
-- Build files have been written to: /path/to/build

$ cmake .. -DMY_VARIABLE=True
MY_VARIABLE=True
MY_VARIABLE evaluates to True
-- Configuring done
-- Generating done
-- Build files have been written to: /path/to/build

$ cmake .. -DMY_VARIABLE=False
MY_VARIABLE=False
-- Configuring done
-- Generating done
-- Build files have been written to: /path/to/build

$ cmake .. -DMY_VARIABLE=1
MY_VARIABLE=1
MY_VARIABLE evaluates to True
-- Configuring done
-- Generating done
-- Build files have been written to: /path/to/build

$ cmake .. -DMY_VARIABLE=0
MY_VARIABLE=0
-- Configuring done
-- Generating done
-- Build files have been written to: /path/to/build

Function to calculate R2 (R-squared) in R

Not sure why this isn't implemented directly in R, but this answer is essentially the same as Andrii's and Wordsforthewise, I just turned into a function for the sake of convenience if somebody uses it a lot like me.

r2_general <-function(preds,actual){ 
  return(1- sum((preds - actual) ^ 2)/sum((actual - mean(actual))^2))
}

How to make the main content div fill height of screen with css

These are not necessary

  • remove height in %
  • remove jQuery

Stretch div using bottom & top :

.mainbody{
    position: absolute;
    top: 40px; /* Header Height */
    bottom: 20px; /* Footer Height */
    width: 100%;
}

check my code : http://jsfiddle.net/aslancods/mW9WF/

or check here:

_x000D_
_x000D_
body {_x000D_
    margin:0;_x000D_
}_x000D_
_x000D_
.header {_x000D_
    height: 40px;_x000D_
    background-color: red;_x000D_
}_x000D_
_x000D_
.mainBody {_x000D_
    background-color: yellow;_x000D_
    position: absolute;_x000D_
    top: 40px;_x000D_
    bottom: 20px;_x000D_
    width:100%;_x000D_
}_x000D_
_x000D_
.content {_x000D_
    color:#fff;_x000D_
}_x000D_
_x000D_
.footer {_x000D_
    height: 20px;_x000D_
    background-color: blue;_x000D_
    _x000D_
    position: absolute;_x000D_
    bottom: 0;_x000D_
    width:100%;_x000D_
}
_x000D_
<div class="header" >_x000D_
    &nbsp;_x000D_
</div>_x000D_
<div class="mainBody">_x000D_
    &nbsp;_x000D_
    <div class="content" >Hello world</div>_x000D_
</div>_x000D_
<div class="footer">_x000D_
    &nbsp;_x000D_
</div>
_x000D_
_x000D_
_x000D_

Entity Framework (EF) Code First Cascade Delete for One-to-Zero-or-One relationship

You will have to use the fluent API to do this.

Try adding the following to your DbContext:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{   
    modelBuilder.Entity<User>()
        .HasOptional(a => a.UserDetail)
        .WithOptionalDependent()
        .WillCascadeOnDelete(true);
}

Call method when home button pressed

use onPause() method to do what you want to do on home button.

How to skip the first n rows in sql query

SQL Server:

select * from table
except
select top N * from table

Oracle up to 11.2:

select * from table
minus
select * from table where rownum <= N

with TableWithNum as (
    select t.*, rownum as Num
    from Table t
)
select * from TableWithNum where Num > N

Oracle 12.1 and later (following standard ANSI SQL)

select *
from table
order by some_column 
offset x rows
fetch first y rows only

They may meet your needs more or less.

There is no direct way to do what you want by SQL. However, it is not a design flaw, in my opinion.

SQL is not supposed to be used like this.

In relational databases, a table represents a relation, which is a set by definition. A set contains unordered elements.

Also, don't rely on the physical order of the records. The row order is not guaranteed by the RDBMS.

If the ordering of the records is important, you'd better add a column such as `Num' to the table, and use the following query. This is more natural.

select * 
from Table 
where Num > N
order by Num

Running command line silently with VbScript and getting output?

Dim path As String = GetFolderPath(SpecialFolder.ApplicationData)
 Dim filepath As String = path + "\" + "your.bat"
    ' Create the file if it does not exist. 
    If File.Exists(filepath) = False Then
        File.Create(filepath)
    Else
    End If
    Dim attributes As FileAttributes
    attributes = File.GetAttributes(filepath)
    If (attributes And FileAttributes.ReadOnly) = FileAttributes.ReadOnly Then
        ' Remove from Readonly the file.
        attributes = RemoveAttribute(attributes, FileAttributes.ReadOnly)
        File.SetAttributes(filepath, attributes)
        Console.WriteLine("The {0} file is no longer RO.", filepath)
    Else
    End If
    If (attributes And FileAttributes.Hidden) = FileAttributes.Hidden Then
        ' Show the file.
        attributes = RemoveAttribute(attributes, FileAttributes.Hidden)
        File.SetAttributes(filepath, attributes)
        Console.WriteLine("The {0} file is no longer Hidden.", filepath)
    Else
    End If
    Dim sr As New StreamReader(filepath)
    Dim input As String = sr.ReadToEnd()
    sr.Close()
    Dim output As String = "@echo off"
    Dim output1 As String = vbNewLine + "your 1st cmd code"
    Dim output2 As String = vbNewLine + "your 2nd cmd code "
    Dim output3 As String = vbNewLine + "exit"
    Dim sw As New StreamWriter(filepath)
    sw.Write(output)
    sw.Write(output1)
    sw.Write(output2)
    sw.Write(output3)
    sw.Close()
    If (attributes And FileAttributes.Hidden) = FileAttributes.Hidden Then
    Else
        ' Hide the file.
        File.SetAttributes(filepath, File.GetAttributes(filepath) Or FileAttributes.Hidden)
        Console.WriteLine("The {0} file is now hidden.", filepath)
    End If
    Dim procInfo As New ProcessStartInfo(path + "\" + "your.bat")
    procInfo.WindowStyle = ProcessWindowStyle.Minimized
    procInfo.WindowStyle = ProcessWindowStyle.Hidden
    procInfo.CreateNoWindow = True
    procInfo.FileName = path + "\" + "your.bat"
    procInfo.Verb = "runas"
    Process.Start(procInfo)

it saves your .bat file to "Appdata of current user" ,if it does not exist and remove the attributes and after that set the "hidden" attributes to file after writing your cmd code and run it silently and capture all output saves it to file so if u wanna save all output of cmd to file just add your like this

code > C:\Users\Lenovo\Desktop\output.txt

just replace word "code" with your .bat file code or command and after that the directory of output file I found one code recently after searching alot if u wanna run .bat file in vb or c# or simply just add this in the same manner in which i have written

INNER JOIN ON vs WHERE clause

ANSI join syntax is definitely more portable.

I'm going through an upgrade of Microsoft SQL Server, and I would also mention that the =* and *= syntax for outer joins in SQL Server is not supported (without compatibility mode) for 2005 SQL server and later.

ReactJS SyntheticEvent stopPropagation() only works with React events?

Update: You can now <Elem onClick={ proxy => proxy.stopPropagation() } />

Making a div vertically scrollable using CSS

You have it covered aside from using the wrong property. The scrollbar can be triggered with any property overflow, overflow-x, or overflow-y and each can be set to any of visible, hidden, scroll, auto, or inherit. You are currently looking at these two:

  • auto - This value will look at the width and height of the box. If they are defined, it won't let the box expand past those boundaries. Instead (if the content exceeds those boundaries), it will create a scrollbar for either boundary (or both) that exceeds its length.

  • scroll - This values forces a scrollbar, no matter what, even if the content does not exceed the boundary set. If the content doesn't need to be scrolled, the bar will appear as "disabled" or non-interactive.

If you always want the vertical scrollbar to appear:

You should use overflow-y: scroll. This forces a scrollbar to appear for the vertical axis whether or not it is needed. If you can't actually scroll the context, it will appear as a"disabled" scrollbar.

If you only want a scrollbar to appear if you can scroll the box:

Just use overflow: auto. Since your content by default just breaks to the next line when it cannot fit on the current line, a horizontal scrollbar won't be created (unless it's on an element that has word-wrapping disabled). For the vertical bar,it will allow the content to expand up to the height you have specified. If it exceeds that height, it will show a vertical scrollbar to view the rest of the content, but will not show a scrollbar if it does not exceed the height.

Can enums be subclassed to add new elements?

I suggest you take the other way around approach.

Instead of extending the existing enumeration, create a larger one and create a subset of it. For exemple if you had an enumeration called PET and you wanted to extend it to ANIMAL you should do this instead:

public enum ANIMAL {
    WOLF,CAT, DOG
} 
EnumSet<ANIMAL> pets = EnumSet.of(ANIMAL.CAT, ANIMAL.DOG);

Be careful, pets is not an immutable collections, you might want to use Guava or Java9 for more safety.

How to set a parameter in a HttpServletRequest?

If you really want to do this, create an HttpServletRequestWrapper.

public class AddableHttpRequest extends HttpServletRequestWrapper {

   private HashMap params = new HashMap();

   public AddableingHttpRequest(HttpServletRequest request) {
           super(request);
   }

   public String getParameter(String name) {
           // if we added one, return that one
           if ( params.get( name ) != null ) {
                 return params.get( name );
           }
           // otherwise return what's in the original request
           HttpServletRequest req = (HttpServletRequest) super.getRequest();
           return validate( name, req.getParameter( name ) );
   }

   public void addParameter( String name, String value ) {
           params.put( name, value );
   }

}

Getting each individual digit from a whole integer

Don't reinvent the wheel. C has sprintf for a reason. Since your variable is called score, I'm guessing this is for a game where you're planning to use the individual digits of the score to display the numeral glyphs as images. In this case, sprintf has convenient format modifiers that will let you zero-pad, space-pad, etc. the score to a fixed width, which you may want to use.

Select the first row by group

A simple ddply option:

ddply(test,.(id),function(x) head(x,1))

If speed is an issue, a similar approach could be taken with data.table:

testd <- data.table(test)
setkey(testd,id)
testd[,.SD[1],by = key(testd)]

or this might be considerably faster:

testd[testd[, .I[1], by = key(testd]$V1]

Detect iPad users using jQuery?

Although the accepted solution is correct for iPhones, it will incorrectly declare both isiPhone and isiPad to be true for users visiting your site on their iPad from the Facebook app.

The conventional wisdom is that iOS devices have a user agent for Safari and a user agent for the UIWebView. This assumption is incorrect as iOS apps can and do customize their user agent. The main offender here is Facebook.

Compare these user agent strings from iOS devices:

# iOS Safari
iPad: Mozilla/5.0 (iPad; CPU OS 5_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9B176 Safari/7534.48.3
iPhone: Mozilla/5.0 (iPhone; CPU iPhone OS 5_0 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9A334 Safari/7534.48.3

# UIWebView
iPad: Mozilla/5.0 (iPad; CPU OS 5_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Mobile/98176
iPhone: Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_1 like Mac OS X; en-us) AppleWebKit/532.9 (KHTML, like Gecko) Mobile/8B117

# Facebook UIWebView
iPad: Mozilla/5.0 (iPad; U; CPU iPhone OS 5_1_1 like Mac OS X; en_US) AppleWebKit (KHTML, like Gecko) Mobile [FBAN/FBForIPhone;FBAV/4.1.1;FBBV/4110.0;FBDV/iPad2,1;FBMD/iPad;FBSN/iPhone OS;FBSV/5.1.1;FBSS/1; FBCR/;FBID/tablet;FBLC/en_US;FBSF/1.0]
iPhone: Mozilla/5.0 (iPhone; U; CPU iPhone OS 5_1_1 like Mac OS X; ru_RU) AppleWebKit (KHTML, like Gecko) Mobile [FBAN/FBForIPhone;FBAV/4.1;FBBV/4100.0;FBDV/iPhone3,1;FBMD/iPhone;FBSN/iPhone OS;FBSV/5.1.1;FBSS/2; tablet;FBLC/en_US]

Note that on the iPad, the Facebook UIWebView's user agent string includes 'iPhone'.

The old way to identify iPhone / iPad in JavaScript:

IS_IPAD = navigator.userAgent.match(/iPad/i) != null;
IS_IPHONE = navigator.userAgent.match(/iPhone/i) != null) || (navigator.userAgent.match(/iPod/i) != null);

If you were to go with this approach for detecting iPhone and iPad, you would end up with IS_IPHONE and IS_IPAD both being true if a user comes from Facebook on an iPad. That could create some odd behavior!

The correct way to identify iPhone / iPad in JavaScript:

IS_IPAD = navigator.userAgent.match(/iPad/i) != null;
IS_IPHONE = (navigator.userAgent.match(/iPhone/i) != null) || (navigator.userAgent.match(/iPod/i) != null);
if (IS_IPAD) {
  IS_IPHONE = false;
}

We declare IS_IPHONE to be false on iPads to cover for the bizarre Facebook UIWebView iPad user agent. This is one example of how user agent sniffing is unreliable. The more iOS apps that customize their user agent, the more issues user agent sniffing will have. If you can avoid user agent sniffing (hint: CSS Media Queries), DO IT.

subtract time from date - moment js

I use moment.js http://momentjs.com/

var start = moment(StartTimeString).toDate().getTime();
var end = moment(EndTimeString).toDate().getTime();
var timespan = end - start;
var duration = moment(timespan);
var output = duration.format("YYYY-MM-DDTHH:mm:ss");

IIS: Idle Timeout vs Recycle

From here:

One way to conserve system resources is to configure idle time-out settings for the worker processes in an application pool. When these settings are configured, a worker process will shut down after a specified period of inactivity. The default value for idle time-out is 20 minutes.

Also check Why is the IIS default app pool recycle set to 1740 minutes?

If you have a just a few sites on your server and you want them to always load fast then set this to zero. Otherwise, when you have 20 minutes without any traffic then the app pool will terminate so that it can start up again on the next visit. The problem is that the first visit to an app pool needs to create a new w3wp.exe worker process which is slow because the app pool needs to be created, ASP.NET or another framework needs to be loaded, and then your application needs to be loaded. That can take a few seconds. Therefore I set that to 0 every chance I have, unless it’s for a server that hosts a lot of sites that don’t always need to be running.

Enter key press behaves like a Tab in Javascript

I reworked the OPs solution into a Knockout binding and thought I'd share it. Thanks very much :-)

Here's a Fiddle

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js" type="text/javascript"></script>
    <script src="http://ajax.aspnetcdn.com/ajax/knockout/knockout-2.2.1.js" type="text/javascript"></script>


</head>
<body>

    <div data-bind="nextFieldOnEnter:true">
        <input type="text" />
        <input type="text" />
        <select>
          <option value="volvo">Volvo</option>
          <option value="saab">Saab</option>
          <option value="mercedes">Mercedes</option>
          <option value="audi">Audi</option>
        </select>
        <input type="text" />
        <input type="text" />
    </div>


    <script type="text/javascript">
    ko.bindingHandlers.nextFieldOnEnter = {
        init: function(element, valueAccessor, allBindingsAccessor) {
            $(element).on('keydown', 'input, select', function (e) {
                var self = $(this)
                , form = $(element)
                  , focusable
                  , next
                ;
                if (e.keyCode == 13) {
                    focusable = form.find('input,a,select,button,textarea').filter(':visible');
                    var nextIndex = focusable.index(this) == focusable.length -1 ? 0 : focusable.index(this) + 1;
                    next = focusable.eq(nextIndex);
                    next.focus();
                    return false;
                }
            });
        }
    };

    ko.applyBindings({});
    </script>
</body>
</html>

OpenCV Error: (-215)size.width>0 && size.height>0 in function imshow

Check if you have "opencv_ffmpeg330.dll" in python27 root directory or of the python version you are using. If not you will find it in "....\OpenCV\opencv\build\bin".

Choose the appropriate version and copy the dll into the root directory of your python installation and re-run the program

Android Location Providers - GPS or Network Provider?

There are some great answers mentioned here. Another approach you could take would be to use some free SDKs available online like Atooma, tranql and Neura, that can be integrated with your Android application (it takes less than 20 min to integrate). Along with giving you the accurate location of your user, it can also give you good insights about your user’s activities. Also, some of them consume less than 1% of your battery

"SDK Platform Tools component is missing!"

Here is another alternative. Download it directly here: http://androidsdkoffline.blogspot.com.ng/p/android-sdk-tools.html.

The present version as of this writing is Android SDK Tools 25.1.7. Unzip it when the download is done and place it in your sdk folder. You can then download other missing files directly from the SDK Manager.

Count number of occurrences for each unique value

select time, coalesce(count(case when activities = 3 then 1 end), 0) as count
from MyTable
group by time

SQL Fiddle Example

Output:

|  TIME | COUNT |
-----------------
| 13:00 |     2 |
| 13:15 |     2 |
| 13:30 |     0 |
| 13:45 |     1 |

If you want to count all the activities in one query, you can do:

select time, 
    coalesce(count(case when activities = 1 then 1 end), 0) as count1,
    coalesce(count(case when activities = 2 then 1 end), 0) as count2,
    coalesce(count(case when activities = 3 then 1 end), 0) as count3,
    coalesce(count(case when activities = 4 then 1 end), 0) as count4,
    coalesce(count(case when activities = 5 then 1 end), 0) as count5
from MyTable
group by time

The advantage of this over grouping by activities, is that it will return a count of 0 even if there are no activites of that type for that time segment.

Of course, this will not return rows for time segments with no activities of any type. If you need that, you'll need to use a left join with table that lists all the possible time segments.

Fitting a histogram with python

Here is an example that uses scipy.optimize to fit a non-linear functions like a Gaussian, even when the data is in a histogram that isn't well ranged, so that a simple mean estimate would fail. An offset constant also would cause simple normal statistics to fail ( just remove p[3] and c[3] for plain gaussian data).

from pylab import *
from numpy import loadtxt
from scipy.optimize import leastsq

fitfunc  = lambda p, x: p[0]*exp(-0.5*((x-p[1])/p[2])**2)+p[3]
errfunc  = lambda p, x, y: (y - fitfunc(p, x))

filename = "gaussdata.csv"
data     = loadtxt(filename,skiprows=1,delimiter=',')
xdata    = data[:,0]
ydata    = data[:,1]

init  = [1.0, 0.5, 0.5, 0.5]

out   = leastsq( errfunc, init, args=(xdata, ydata))
c = out[0]

print "A exp[-0.5((x-mu)/sigma)^2] + k "
print "Parent Coefficients:"
print "1.000, 0.200, 0.300, 0.625"
print "Fit Coefficients:"
print c[0],c[1],abs(c[2]),c[3]

plot(xdata, fitfunc(c, xdata))
plot(xdata, ydata)

title(r'$A = %.3f\  \mu = %.3f\  \sigma = %.3f\ k = %.3f $' %(c[0],c[1],abs(c[2]),c[3]));

show()

Output:

A exp[-0.5((x-mu)/sigma)^2] + k 
Parent Coefficients:
1.000, 0.200, 0.300, 0.625
Fit Coefficients:
0.961231625289 0.197254597618 0.293989275502 0.65370344131

gaussian plot with fit

GridLayout (not GridView) how to stretch all children evenly

In my case I was adding the buttons dynamically so my solution required some XML part and some Java part. I had to find and mix solutions from a few different places and thought I will share it here so someone else looking for the similar solution might find it helpful.

First part of my layout file XML...

<android.support.v7.widget.GridLayout
    xmlns:grid="http://schemas.android.com/apk/res-auto"
    android:id="@+id/gl_Options"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    grid:useDefaultMargins="true">
</android.support.v7.widget.GridLayout>

grid:useDefaultMargins="true" is not required but I added because that looked better to me, you may apply other visual affects (e.g. padding) as mentioned in some answers here. Now for the buttons as I have to add them dynamically. Here is the Java part of my code to make these buttons, I am including only those lines related to this context. Assume I have to make buttons from as many myOptions are available to my code and I am not copying the OnClickListener code as well.

import android.support.v7.widget.GridLayout;   //Reference to Library

public class myFragment extends Fragment{
    GridLayout gl_Options;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        gl_AmountOptions = (GridLayout)view.findViewById( R.id.gl_AmountOptions );
        ...
        gl_Options.removeAllViews();     // Remove all existing views
        gl_AmountOptions.setColumnCount( myOptions.length <= 9 ? 3: 4 );  // Set appropriate number of columns

        for( String opt : myOptions ) {
            GridLayout.LayoutParams lParams   = new GridLayout.LayoutParams( GridLayout.spec( GridLayout.UNDEFINED, 1f), GridLayout.spec( GridLayout.UNDEFINED, 1f));
            // The above defines LayoutParameters as not specified Column and Row with grid:layout_columnWeight="1" and grid:layout_rowWeight="1"
            lParams.width = 0;    // Setting width to "0dp" so weight is applied instead

            Button b = new Button(this.getContext());
            b.setText( opt );
            b.setLayoutParams(lParams);
            b.setOnClickListener( myClickListener );
            gl_Options.addView( b );
        }
    }
}

As we are using GridLayout from support library and not the standard GridLayout, we have to tell grade about that in YourProject.grade file.

dependencies {
    compile 'com.android.support:appcompat-v7:23.4.0'
    ...
    compile 'com.android.support:gridlayout-v7:23.4.0'
}

Using client certificate in Curl command

This is how I did it:

curl -v \
  --key ./admin-key.pem \
  --cert ./admin.pem \
  https://xxxx/api/v1/

WPF MVVM ComboBox SelectedItem or SelectedValue not working

I have a very simply answer for this problem. First add the following code to the View IsSynchronizedWithCurrentItem="True".

Next when ever you assign a new object in the ViewModel to that Property SelectedObject should be saved to that Property and not the private member.

The viewmodel Proptery should look like this

    public Role SelectedObject 
    {
        get { return object; }
        set
        {
            if (value != null)
            {
                if (!object.Equals(value))
                {
                    object = value;
                    OnPropertyChanged(() => SelectedObject );
                }
            }
        }
    }

This should fix the issue.

Nginx not running with no error message

For what it's worth: I just had the same problem, after editing the nginx.conf file. I tried and tried restarting it by commanding sudo nginx restart and various other commands. None of them produced any output. Commanding sudo nginx -t to check the configuration file gave the output sudo: nginx: command not found, which was puzzling. I was starting to think there were problems with the path.

Finally, I logged in as root (sudo su) and commanded sudo nginx restart. Now, the command displayed an error message concerning the configuration file. After fixing that, it restarted successfully.

Set CFLAGS and CXXFLAGS options using CMake

On Unix systems, for several projects, I added these lines into the CMakeLists.txt and it was compiling successfully because base (/usr/include) and local includes (/usr/local/include) go into separated directories:

set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -I/usr/local/include -L/usr/local/lib")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -I/usr/local/include")
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -L/usr/local/lib")

It appends the correct directory, including paths for the C and C++ compiler flags and the correct directory path for the linker flags.

Note: C++ compiler (c++) doesn't support -L, so we have to use CMAKE_EXE_LINKER_FLAGS

How to show/hide JPanels in a JFrame?

Call parent.remove(panel), where parent is the container that you want the frame in and panel is the panel you want to add.

CSS image resize percentage of itself?

Try zoom property

<img src="..." style="zoom: 0.5" />

Edit: Apparently, FireFox doesn't support zoom property. You should use;

-moz-transform: scale(0.5);

for FireFox.

regex for zip-code

I know this may be obvious for most people who use RegEx frequently, but in case any readers are new to RegEx, I thought I should point out an observation I made that was helpful for one of my projects.

In a previous answer from @kennytm:

^\d{5}(?:[-\s]\d{4})?$

…? = The pattern before it is optional (for condition 1)

If you want to allow both standard 5 digit and +4 zip codes, this is a great example.

To match only zip codes in the US 'Zip + 4' format as I needed to do (conditions 2 and 3 only), simply remove the last ? so it will always match the last 5 character group.

A useful tool I recommend for tinkering with RegEx is linked below:

https://regexr.com/

I use this tool frequently when I find RegEx that does something similar to what I need, but could be tailored a bit better. It also has a nifty RegEx reference menu and informative interface that keeps you aware of how your changes impact the matches for the sample text you entered.

If I got anything wrong or missed an important piece of information, please correct me.

Checking if any elements in one list are in another

Your original approach can work with a list comprehension:

def listCompare():
  list1 = [1, 2, 3, 4, 5]
  list2 = [5, 6, 7, 8, 9]
  if [item for item in list1 if item in list2]:
    print("Number was found")
  else:
    print("Number not in list")

How can I grep for a string that begins with a dash/hyphen?

grep "^-X" file

It will grep and pick all the lines form the file. ^ in the grep"^" indicates a line starting with

What does "xmlns" in XML mean?

It defines an XML Namespace.

In your example, the Namespace Prefix is "android" and the Namespace URI is "http://schemas.android.com/apk/res/android"

In the document, you see elements like: <android:foo />

Think of the namespace prefix as a variable with a short name alias for the full namespace URI. It is the equivalent of writing <http://schemas.android.com/apk/res/android:foo /> with regards to what it "means" when an XML parser reads the document.

NOTE: You cannot actually use the full namespace URI in place of the namespace prefix in an XML instance document.

Check out this tutorial on namespaces: http://www.sitepoint.com/xml-namespaces-explained/

A CORS POST request works from plain JavaScript, but why not with jQuery?

You are sending "params" in js: request.send(params);

but "data" in jquery". Is data defined?: data:data,

Also, you have an error in the URL:

$.ajax( {url:url,
         type:"POST",
         dataType:"json",
         data:data, 
         success:function(data, textStatus, jqXHR) {alert("success");},
         error: function(jqXHR, textStatus, errorThrown) {alert("failure");}
});

You are mixing the syntax with the one for $.post


Update: I was googling around based on monsur answer, and I found that you need to add Access-Control-Allow-Headers: Content-Type (below is the full paragraph)

http://metajack.im/2010/01/19/crossdomain-ajax-for-xmpp-http-binding-made-easy/

How CORS Works

CORS works very similarly to Flash's crossdomain.xml file. Basically, the browser will send a cross-domain request to a service, setting the HTTP header Origin to the requesting server. The service includes a few headers like Access-Control-Allow-Origin to indicate whether such a request is allowed.

For the BOSH connection managers, it is enough to specify that all origins are allowed, by setting the value of Access-Control-Allow-Origin to *. The Content-Type header must also be white-listed in the Access-Control-Allow-Headers header.

Finally, for certain types of requests, including BOSH connection manager requests, the permissions check will be pre-flighted. The browser will do an OPTIONS request and expect to get back some HTTP headers that indicate which origins are allowed, which methods are allowed, and how long this authorization will last. For example, here is what the Punjab and ejabberd patches I did return for OPTIONS:

Access-Control-Allow-Origin: *
Access-Control-Allow-Methods: GET, POST, OPTIONS
Access-Control-Allow-Headers: Content-Type 
Access-Control-Max-Age: 86400

Application Error - The connection to the server was unsuccessful. (file:///android_asset/www/index.html)

Please remove remotely linked jQuery files such as: https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js

Instead, download this file and load it from your local js folder, making the URI:

js/jquery.min.js

Node.js Best Practice Exception Handling

One instance where using a try-catch might be appropriate is when using a forEach loop. It is synchronous but at the same time you cannot just use a return statement in the inner scope. Instead a try and catch approach can be used to return an Error object in the appropriate scope. Consider:

function processArray() {
    try { 
       [1, 2, 3].forEach(function() { throw new Error('exception'); }); 
    } catch (e) { 
       return e; 
    }
}

It is a combination of the approaches described by @balupton above.

How to convert a huge list-of-vector to a matrix more efficiently?

I think you want

output <- do.call(rbind,lapply(z,matrix,ncol=10,byrow=TRUE))

i.e. combining @BlueMagister's use of do.call(rbind,...) with an lapply statement to convert the individual list elements into 11*10 matrices ...

Benchmarks (showing @flodel's unlist solution is 5x faster than mine, and 230x faster than the original approach ...)

n <- 1000
z <- replicate(n,matrix(1:110,ncol=10,byrow=TRUE),simplify=FALSE)
library(rbenchmark)
origfn <- function(z) {
    output <- NULL 
    for(i in 1:length(z))
        output<- rbind(output,matrix(z[[i]],ncol=10,byrow=TRUE))
}
rbindfn <- function(z) do.call(rbind,lapply(z,matrix,ncol=10,byrow=TRUE))
unlistfn <- function(z) matrix(unlist(z), ncol = 10, byrow = TRUE)

##          test replications elapsed relative user.self sys.self 
## 1   origfn(z)          100  36.467  230.804    34.834    1.540  
## 2  rbindfn(z)          100   0.713    4.513     0.708    0.012 
## 3 unlistfn(z)          100   0.158    1.000     0.144    0.008 

If this scales appropriately (i.e. you don't run into memory problems), the full problem would take about 130*0.2 seconds = 26 seconds on a comparable machine (I did this on a 2-year-old MacBook Pro).

How to toggle boolean state of react component?

Depending on your context; this will allow you to update state given the mouseEnter function. Either way, by setting a state value to either true:false you can update that state value given any function by setting it to the opposing value with !this.state.variable

state = {
  hover: false
}

onMouseEnter = () => {
  this.setState({
    hover: !this.state.hover
  });
};

Combining two lists and removing duplicates, without removing duplicates in original list

resulting_list = first_list + [i for i in second_list if i not in first_list]

getting the difference between date in days in java

Calendar start = Calendar.getInstance();
Calendar end = Calendar.getInstance();
start.set(2010, 7, 23);
end.set(2010, 8, 26);
Date startDate = start.getTime();
Date endDate = end.getTime();
long startTime = startDate.getTime();
long endTime = endDate.getTime();
long diffTime = endTime - startTime;
long diffDays = diffTime / (1000 * 60 * 60 * 24);
DateFormat dateFormat = DateFormat.getDateInstance();
System.out.println("The difference between "+
  dateFormat.format(startDate)+" and "+
  dateFormat.format(endDate)+" is "+
  diffDays+" days.");

This will not work when crossing daylight savings time (or leap seconds) as orange80 pointed out and might as well not give the expected results when using different times of day. Using JodaTime might be easier for correct results, as the only correct way with plain Java before 8 I know is to use Calendar's add and before/after methods to check and adjust the calculation:

start.add(Calendar.DAY_OF_MONTH, (int)diffDays);
while (start.before(end)) {
    start.add(Calendar.DAY_OF_MONTH, 1);
    diffDays++;
}
while (start.after(end)) {
    start.add(Calendar.DAY_OF_MONTH, -1);
    diffDays--;
}

Why doesn't JUnit provide assertNotEquals methods?

The obvious reason that people wanted assertNotEquals() was to compare builtins without having to convert them to full blown objects first:

Verbose example:

....
assertThat(1, not(equalTo(Integer.valueOf(winningBidderId))));
....

vs.

assertNotEqual(1, winningBidderId);

Sadly since Eclipse doesn't include JUnit 4.11 by default you must be verbose.

Caveat I don't think the '1' needs to be wrapped in an Integer.valueOf() but since I'm newly returned from .NET don't count on my correctness.

Uncaught syntaxerror: unexpected identifier?

There are errors here :

var formTag = document.getElementsByTagName("form"), // form tag is an array
selectListItem = $('select'),
makeSelect = document.createElement('select'),
makeSelect.setAttribute("id", "groups");

The code must change to:

var formTag = document.getElementsByTagName("form");
var selectListItem = $('select');
var makeSelect = document.createElement('select');
makeSelect.setAttribute("id", "groups");

By the way, there is another error at line 129 :

var createLi.appendChild(createSubList);

Replace it with:

createLi.appendChild(createSubList);

Programmatically Check an Item in Checkboxlist where text is equal to what I want

Assuming that the items in your CheckedListBox are strings:

  for (int i = 0; i < checkedListBox1.Items.Count; i++)
  {
    if ((string)checkedListBox1.Items[i] == value)
    {
      checkedListBox1.SetItemChecked(i, true);
    }
  }

Or

  int index = checkedListBox1.Items.IndexOf(value);

  if (index >= 0)
  {
    checkedListBox1.SetItemChecked(index, true);
  }

Bash command line and input limit

Ok, Denizens. So I have accepted the command line length limits as gospel for quite some time. So, what to do with one's assumptions? Naturally- check them.

I have a Fedora 22 machine at my disposal (meaning: Linux with bash4). I have created a directory with 500,000 inodes (files) in it each of 18 characters long. The command line length is 9,500,000 characters. Created thus:

seq 1 500000 | while read digit; do
    touch $(printf "abigfilename%06d\n" $digit);
done

And we note:

$ getconf ARG_MAX
2097152

Note however I can do this:

$ echo * > /dev/null

But this fails:

$ /bin/echo * > /dev/null
bash: /bin/echo: Argument list too long

I can run a for loop:

$ for f in *; do :; done

which is another shell builtin.

Careful reading of the documentation for ARG_MAX states, Maximum length of argument to the exec functions. This means: Without calling exec, there is no ARG_MAX limitation. So it would explain why shell builtins are not restricted by ARG_MAX.

And indeed, I can ls my directory if my argument list is 109948 files long, or about 2,089,000 characters (give or take). Once I add one more 18-character filename file, though, then I get an Argument list too long error. So ARG_MAX is working as advertised: the exec is failing with more than ARG_MAX characters on the argument list- including, it should be noted, the environment data.

Invoke(Delegate)

It means that the delegate will run on the UI thread, even if you call that method from a background worker or thread-pool thread. UI elements have thread affinity - they only like talking directly to one thread: the UI thread. The UI thread is defined as the thread that created the control instance, and is therefore associated with the window handle. But all of that is an implementation detail.

The key point is: you would call this method from a worker thread so that you can access the UI (to change the value in a label, etc) - since you are not allowed to do that from any other thread than the UI thread.

How to format a UTC date as a `YYYY-MM-DD hh:mm:ss` string using NodeJS?

For date formatting the most easy way is using moment lib. https://momentjs.com/

const moment = require('moment')
const current = moment().utc().format('Y-M-D H:M:S')

How to match a substring in a string, ignoring case

There's another post here. Try looking at this.

BTW, you're looking for the .lower() method:

string1 = "hi"
string2 = "HI"
if string1.lower() == string2.lower():
    print "Equals!"
else:
    print "Different!"

anaconda/conda - install a specific package version

If any of these characters, '>', '<', '|' or '*', are used, a single or double quotes must be used

conda install [-y] package">=version"
conda install [-y] package'>=low_version, <=high_version'
conda install [-y] "package>=low_version, <high_version"

conda install -y torchvision">=0.3.0"
conda install  openpyxl'>=2.4.10,<=2.6.0'
conda install "openpyxl>=2.4.10,<3.0.0"

where option -y, --yes Do not ask for confirmation.

Here is a summary:

Format         Sample Specification     Results
Exact          qtconsole==4.5.1         4.5.1
Fuzzy          qtconsole=4.5            4.5.0, 4.5.1, ..., etc.
>=, >, <, <=  "qtconsole>=4.5"          4.5.0 or higher
               qtconsole"<4.6"          less than 4.6.0

OR            "qtconsole=4.5.1|4.5.2"   4.5.1, 4.5.2
AND           "qtconsole>=4.3.1,<4.6"   4.3.1 or higher but less than 4.6.0

Potion of the above information credit to Conda Cheat Sheet

Tested on conda 4.7.12

how to set default main class in java?

If you're creating 2 executable JAR files, each will have it's own manifest file, and each manifest file will specify the class that contains the main() method you want to use to start execution.

In each JAR file, the manifest will be a file with the following path / name inside the JAR - META-INF/MANIFEST.MF

There are ways to specify alternatively named files as a JAR's manifest using the JAR command-line parameters.

The specific class you want to use is specified using Main-Class: package.classname inside the META-INF/MANIFEST.MF file.

As for how to do this in Netbeans - not sure off the top of my head - I usually use IntelliJ and / or Eclipse and usually build the JAR through ANT or Maven anyway.

Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[]]

I had met a similar problem, after i add a scope property of servlet dependency in pom.xml

 <dependency>
  <groupId>javax.servlet</groupId>
  <artifactId>javax.servlet-api</artifactId>
  <version>3.0.1</version>
    <scope>provided</scope>
</dependency>

Then it was ok . maybe that will help you.

Indenting code in Sublime text 2?

There is no default shortcut for reindenting a file. However you can create one by following eznme's answer above.

You can also use the Command Palette by pressing:

  1. Control+Shift+P (or ?+Shift+P on a Mac)
  2. Type the first few characters of Reindent e.g: rein
  3. Press Enter to run the command
    (The first command at the top should now show Indentation: Reindent Lines)

get the titles of all open windows

Hera's the function UpdateWindowsList_WindowMenu() that you must call after any operations are performed on Tabs.Here windowToolStripMenuItem is the menu item added to Window Menu to menu strip.

public void UpdateWindowsList_WindowMenu()  
{  
    //get all tab pages from tabControl1  
    TabControl.TabPageCollection tabcoll = tabControl1.TabPages;  

    //get  windowToolStripMenuItem drop down menu items count  
    int n = windowToolStripMenuItem.DropDownItems.Count;  

    //remove all menu items from of windowToolStripMenuItem  
    for (int i = n - 1; i >=2; i--)  
    {  
        windowToolStripMenuItem.DropDownItems.RemoveAt(i);  
    }  

    //read each tabpage from tabcoll and add each tabpage text to windowToolStripMenuItem  
    foreach (TabPage tabpage in tabcoll)  
    {  
        //create Toolstripmenuitem  
        ToolStripMenuItem menuitem = new ToolStripMenuItem();  
        String s = tabpage.Text;  
        menuitem.Text = s;  

        if (tabControl1.SelectedTab == tabpage)  
        {  
            menuitem.Checked = true;  
        }  
        else  
        {  
            menuitem.Checked = false;  
        }  

        //add menuitem to windowToolStripMenuItem  
        windowToolStripMenuItem.DropDownItems.Add(menuitem);  

        //add click events to each added menuitem  
        menuitem.Click += new System.EventHandler(WindowListEvent_Click);  
    }  
}  

private void WindowListEvent_Click(object sender, EventArgs e)  
{  
    //casting ToolStripMenuItem to ToolStripItem  
    ToolStripItem toolstripitem = (ToolStripItem)sender;  

    //create collection of tabs of tabContro1  
    //check every tab text is equal to clicked menuitem then select the tab  
    TabControl.TabPageCollection tabcoll = tabControl1.TabPages;  
    foreach (TabPage tb in tabcoll)  
    {  
        if (toolstripitem.Text == tb.Text)  
        {  
            tabControl1.SelectedTab = tb;  
            //call UpdateWindowsList_WindowMenu() to perform changes on menuitems  
            UpdateWindowsList_WindowMenu();  
        }  
    }  
}  

Content Type application/soap+xml; charset=utf-8 was not supported by service

In my case same error was caused by missing

[DataContract]
...
[DataMember] 

attributes in the returned data type.

Check for that and try addinging those and see if it helps.

How to listen to the window scroll event in a VueJS component?

I know this is an old question, but I found a better solution with Vue.js 2.0+ Custom Directives: I needed to bind the scroll event too, then I implemented this.

First of, using @vue/cli, add the custom directive to src/main.js (before the Vue.js instance) or wherever you initiate it:

Vue.directive('scroll', {
  inserted: function(el, binding) {
    let f = function(evt) {
      if (binding.value(evt, el)) {
        window.removeEventListener('scroll', f);
      }
    }
    window.addEventListener('scroll', f);
  }
});

Then, add the custom v-scroll directive to the element and/or the component you want to bind on. Of course you have to insert a dedicated method: I used handleScroll in my example.

<my-component v-scroll="handleScroll"></my-component>

Last, add your method to the component.

methods: {
  handleScroll: function() {
    // your logic here
  }
}

You don’t have to care about the Vue.js lifecycle anymore here, because the custom directive itself does.

CSS center display inline block?

You don't need to use "display: table". The reason your margin: 0 auto centering attempt doesn't work is because you didn't specify a width.

This will work just fine:

.wrap {
    background: #aaa;
    margin: 0 auto;
    width: some width in pixels since it's the container;
}

You don't need to specify display: block since that div will be block by default. You can also probably lose the overflow: hidden.

Python Remove last char from string and return it

I decided to go with a for loop and just avoid the item in question, is it an acceptable alternative?

new = ''
for item in str:
    if item == str[n]:
        continue
    else:
        new += item

Xcode 4: How do you view the console?

Here' an alternative

In Xcode 4 short cut to display and hide console is (command-shift-Y) , this will show the console and debugger below ur text edior in the same window.

scipy.misc module has no attribute imread?

imread is depreciated after version 1.2.0! So to solve this issue I had to install version 1.1.0.

pip install scipy==1.1.0

What is a callback function?

One important usage area is that you register one of your function as a handle (i.e. a callback) and then send a message / call some function to do some work or processing. Now after the processing is done, the called function would call our registered function (i.e. now call back is done), thus indicating us processing is done.
This wikipedia link explains quite well graphically.

How to put a Scanner input into an array... for example a couple of numbers

List<Double> numbers = new ArrayList<Double>();
double sum = 0;

Scanner scan = new Scanner(System.in);
while(scan.hasNext()){
    double value = scan.nextDouble();
    numbers.add(value);
    sum += value;
}

double average = sum / numbers.size();

check if a std::vector contains a certain object?

If searching for an element is important, I'd recommend std::set instead of std::vector. Using this:

std::find(vec.begin(), vec.end(), x) runs in O(n) time, but std::set has its own find() member (ie. myset.find(x)) which runs in O(log n) time - that's much more efficient with large numbers of elements

std::set also guarantees all the added elements are unique, which saves you from having to do anything like if not contained then push_back()....

How to call base.base.method()?

public class A
{
    public int i = 0;
    internal virtual void test()
    {
        Console.WriteLine("A test");
    }
}

public class B : A
{
    public new int i = 1;
    public new void test()
    {
        Console.WriteLine("B test");
    }
}

public class C : B
{
    public new int i = 2;
    public new void test()
    {
        Console.WriteLine("C test - ");
        (this as A).test(); 
    }
}

Why use argparse rather than optparse?

The best source for rationale for a Python addition would be its PEP: PEP 389: argparse - New Command Line Parsing Module, in particular, the section entitled, Why aren't getopt and optparse enough?

Clear listview content?

Remove your items from your custom adapter and call notifyDataSetChanged().

How to create a css rule for all elements except one class?

The negation pseudo-class seems to be what you are looking for.

table:not(.dojoxGrid) {color:red;}

It's not supported by = IE8 though.

Extracting time from POSIXct

The time_t value for midnight GMT is always divisible by 86400 (24 * 3600). The value for seconds-since-midnight GMT is thus time %% 86400.

The hour in GMT is (time %% 86400) / 3600 and this can be used as the x-axis of the plot:

plot((as.numeric(times) %% 86400)/3600, val)

enter image description here

To adjust for a time zone, adjust the time before taking the modulus, by adding the number of seconds that your time zone is ahead of GMT. For example, US central daylight saving time (CDT) is 5 hours behind GMT. To plot against the time in CDT, the following expression is used:

plot(((as.numeric(times) - 5*3600) %% 86400)/3600, val)

phpMyAdmin on MySQL 8.0

I went to system

preferences -> mysql -> initialize database -> use legacy password encryption(instead of strong) -> entered same password

as my config.inc.php file, restarted the apache server and it worked. I was still suspicious about it so I stopped the apache and mysql server and started them again and now it's working.

How to use HttpWebRequest (.NET) asynchronously?

Use HttpWebRequest.BeginGetResponse()

HttpWebRequest webRequest;

void StartWebRequest()
{
    webRequest.BeginGetResponse(new AsyncCallback(FinishWebRequest), null);
}

void FinishWebRequest(IAsyncResult result)
{
    webRequest.EndGetResponse(result);
}

The callback function is called when the asynchronous operation is complete. You need to at least call EndGetResponse() from this function.

How do I diff the same file between two different commits on the same branch?

Here is a Perl script that prints out Git diff commands for a given file as found in a Git log command.

E.g.

git log pom.xml | perl gldiff.pl 3 pom.xml

Yields:

git diff 5cc287:pom.xml e8e420:pom.xml
git diff 3aa914:pom.xml 7476e1:pom.xml
git diff 422bfd:pom.xml f92ad8:pom.xml

which could then be cut and pasted in a shell window session or piped to /bin/sh.

Notes:

  1. the number (3 in this case) specifies how many lines to print
  2. the file (pom.xml in this case) must agree in both places (you could wrap it in a shell function to provide the same file in both places) or put it in a binary directory as a shell script

Code:

# gldiff.pl
use strict;

my $max  = shift;
my $file = shift;

die "not a number" unless $max =~ m/\d+/;
die "not a file"   unless -f $file;

my $count;
my @lines;

while (<>) {
    chomp;
    next unless s/^commit\s+(.*)//;
    my $commit = $1;
    push @lines, sprintf "%s:%s", substr($commit,0,6),$file;
    if (@lines == 2) {
        printf "git diff %s %s\n", @lines;
        @lines = ();
    }
    last if ++$count >= $max *2;
}

Creating and playing a sound in swift

Here's a bit of code I've got added to FlappySwift that works:

import SpriteKit
import AVFoundation

class GameScene: SKScene {

    // Grab the path, make sure to add it to your project!
    var coinSound = NSURL(fileURLWithPath: Bundle.main.path(forResource: "coin", ofType: "wav")!)
    var audioPlayer = AVAudioPlayer()

    // Initial setup
    override func didMoveToView(view: SKView) {
        audioPlayer = AVAudioPlayer(contentsOfURL: coinSound, error: nil)
        audioPlayer.prepareToPlay()
    }

    // Trigger the sound effect when the player grabs the coin
    func didBeginContact(contact: SKPhysicsContact!) {
        audioPlayer.play()
    }

}

What is sr-only in Bootstrap 3?

As JoshC said, the class .sr-only is used to visually hide the information used for screen readers only. But not only to hide labels. You might consider hiding various other elements such as "skip to main content" link, icons which have an alternative texts etc.

BTW. you can also use .sr-only sr-only-focusable if you need the element to become visible when focused e.g. "skip to main content"

If you want make your website even more accessible I recommend to start here:

Why?

According to the World Health Organization, 285 million people have vision impairments. So making a website accessible is important.

IMPORTANT: Avoid treating disabled users differently. Generally speaking try to avoid developing a different content for different groups of users. Instead try to make accessible the existing content so that it simply works out-of-the-box and for all not specifically targeting e.g. screen readers. In other words don't try to reinvent the wheel. Otherwise the resulting accessibility will often be worse than if there was nothing developed at all. We developers should not assume how those users will use our website. So be very careful when you need to develop such solutions. Obviously a "skip link" is a good example of such content if it's made visible when focused. But there many bad examples too. Such would be hiding from a screen reader a "zoom" button on the map assuming that it has no relevance to blind users. But surprisingly, a zoom function indeed is used among blind users! They like to download images like many other users do (even in high resolution), for sending them to somebody else or for using them in some other context. Source - Read more @ADG: Bad ARIA practices

Difference between single and double quotes in Bash

If you're referring to what happens when you echo something, the single quotes will literally echo what you have between them, while the double quotes will evaluate variables between them and output the value of the variable.

For example, this

#!/bin/sh
MYVAR=sometext
echo "double quotes gives you $MYVAR"
echo 'single quotes gives you $MYVAR'

will give this:

double quotes gives you sometext
single quotes gives you $MYVAR

Write single CSV file using spark-csv

spark.sql("select * from df").coalesce(1).write.option("mode","append").option("header","true").csv("/your/hdfs/path/")

spark.sql("select * from df") --> this is dataframe

coalesce(1) or repartition(1) --> this will make your output file to 1 part file only

write --> writing data

option("mode","append") --> appending data to existing directory

option("header","true") --> enabling header

csv("") --> write as CSV file & its output location in HDFS

How to determine whether an object has a given property in JavaScript

Since question was regarding clunkiness of property checking, and one regular usecase for that being validation of function argument options objects, thought I'd mention a library-free short way of testing existence of multiple properties. Disclaimer: It does require ECMAScript 5 (but IMO anyone still using IE8 deserves a broken web).

function f(opts) {
  if(!["req1","req2"].every(opts.hasOwnProperty, opts)) {
      throw new Error("IllegalArgumentException");
  }
  alert("ok");
}
f({req1: 123});  // error
f({req1: 123, req2: 456});  // ok

Django datetime issues (default=datetime.now())

The datetime.now() is evaluated when the class is created, not when new record is being added to the database.

To achieve what you want define this field as:

date = models.DateTimeField(auto_now_add=True)

This way the date field will be set to current date for each new record.

What is a database transaction?

A transaction is a unit of work that you want to treat as "a whole." It has to either happen in full or not at all.

A classical example is transferring money from one bank account to another. To do that you have first to withdraw the amount from the source account, and then deposit it to the destination account. The operation has to succeed in full. If you stop halfway, the money will be lost, and that is Very Bad.

In modern databases transactions also do some other things - like ensure that you can't access data that another person has written halfway. But the basic idea is the same - transactions are there to ensure, that no matter what happens, the data you work with will be in a sensible state. They guarantee that there will NOT be a situation where money is withdrawn from one account, but not deposited to another.

Aligning a float:left div to center?

use display:inline-block; instead of float

you can't centre floats, but inline-blocks centre as if they were text, so on the outer overall container of your "row" - you would set text-align: center; then for each image/caption container (it's those which would be inline-block;) you can re-align the text to left if you require

How can I stop "property does not exist on type JQuery" syntax errors when using Typescript?

You could cast it to <any> or extend the jquery typing to add your own method.

 (<any>$("div.printArea")).printArea();

//Or add your own custom methods (Assuming this is added by yourself as a part of custom plugin)

interface JQuery {
    printArea():void;
}

How to remove multiple deleted files in Git repository

The best solution if you don't care about staging modified files is to use git add -u as said by mshameers and/or pb2q.

If you just want to remove deleted files, but not stage any modified ones, I think you should use the ls-files argument with the --deleted option (no need to use regex or other complex args/options) :

git ls-files --deleted | xargs git rm

javascript regex for password containing at least 8 characters, 1 number, 1 upper and 1 lowercase

Your regex only allows exactly 8 characters. Use {8,} to specify eight or more instead of {8}.

But why would you limit the allowed character range for your passwords? 8-character alphanumeric passwords can be bruteforced by my phone within minutes.

Why isn't .ico file defined when setting window's icon?

I had the same problem too, but I found a solution.

root.mainloop()

from tkinter import *
    
# must add
root = Tk()
root.title("Calculator")
root.iconbitmap(r"image/icon.ico")
    
root.mainloop()

In the example, what python needed is an icon file, so when you dowload an icon as .png it won't work cause it needs an .ico file. So you need to find converters to convert your icon from png to ico.

MVC pattern on Android

I agree with JDPeckham, and I believe that XML alone is not sufficient to implement the UI part of an application.

However, if you consider the Activity as part of the view then implementing MVC is quite straightforward. You can override Application (as returned by getApplication() in Activity) and it's here that you can create a controller that survives for the lifetime of your application.

(Alternatively you can use the singleton pattern as suggested by the Application documentation)

Python data structure sort list alphabetically

You're dealing with a python list, and sorting it is as easy as doing this.

my_list = ['Stem', 'constitute', 'Sedge', 'Eflux', 'Whim', 'Intrigue']
my_list.sort()

Get the closest number out of an array

This solution uses ES5 existential quantifier Array#some, which allows to stop the iteration, if a condition is met.

Opposit of Array#reduce, it does not need to iterate all elements for one result.

Inside the callback, an absolute delta between the searched value and actual item is taken and compared with the last delta. If greater or equal, the iteration stops, because all other values with their deltas are greater than the actual value.

If the delta in the callback is smaller, then the actual item is assigned to the result and the delta is saved in lastDelta.

Finally, smaller values with equal deltas are taken, like in the below example of 22, which results in 2.

If there is a priority of greater values, the delta check has to be changed from:

if (delta >= lastDelta) {

to:

if (delta > lastDelta) {
//       ^^^ without equal sign

This would get with 22, the result 42 (Priority of greater values).

This function needs sorted values in the array.


Code with priority of smaller values:

_x000D_
_x000D_
function closestValue(array, value) {_x000D_
    var result,_x000D_
        lastDelta;_x000D_
_x000D_
    array.some(function (item) {_x000D_
        var delta = Math.abs(value - item);_x000D_
        if (delta >= lastDelta) {_x000D_
            return true;_x000D_
        }_x000D_
        result = item;_x000D_
        lastDelta = delta;_x000D_
    });_x000D_
    return result;_x000D_
}_x000D_
_x000D_
var data = [2, 42, 82, 122, 162, 202, 242, 282, 322, 362];_x000D_
_x000D_
console.log(21, closestValue(data, 21)); // 2_x000D_
console.log(22, closestValue(data, 22)); // 2  smaller value_x000D_
console.log(23, closestValue(data, 23)); // 42_x000D_
console.log(80, closestValue(data, 80)); // 82
_x000D_
_x000D_
_x000D_

Code with priority of greater values:

_x000D_
_x000D_
function closestValue(array, value) {_x000D_
    var result,_x000D_
        lastDelta;_x000D_
_x000D_
    array.some(function (item) {_x000D_
        var delta = Math.abs(value - item);_x000D_
        if (delta > lastDelta) {_x000D_
            return true;_x000D_
        }_x000D_
        result = item;_x000D_
        lastDelta = delta;_x000D_
    });_x000D_
    return result;_x000D_
}_x000D_
_x000D_
var data = [2, 42, 82, 122, 162, 202, 242, 282, 322, 362];_x000D_
_x000D_
console.log(21, closestValue(data, 21)); //  2_x000D_
console.log(22, closestValue(data, 22)); // 42 greater value_x000D_
console.log(23, closestValue(data, 23)); // 42_x000D_
console.log(80, closestValue(data, 80)); // 82
_x000D_
_x000D_
_x000D_

Remove and Replace Printed items

Just use CR to go to beginning of the line.

import time
for x in range (0,5):  
    b = "Loading" + "." * x
    print (b, end="\r")
    time.sleep(1)

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

Here's a pl/pgsql function that locates records where any column contains a specific value. It takes as arguments the value to search in text format, an array of table names to search into (defaults to all tables) and an array of schema names (defaults all schema names).

It returns a table structure with schema, name of table, name of column and pseudo-column ctid (non-durable physical location of the row in the table, see System Columns)

CREATE OR REPLACE FUNCTION search_columns(
    needle text,
    haystack_tables name[] default '{}',
    haystack_schema name[] default '{}'
)
RETURNS table(schemaname text, tablename text, columnname text, rowctid text)
AS $$
begin
  FOR schemaname,tablename,columnname IN
      SELECT c.table_schema,c.table_name,c.column_name
      FROM information_schema.columns c
        JOIN information_schema.tables t ON
          (t.table_name=c.table_name AND t.table_schema=c.table_schema)
        JOIN information_schema.table_privileges p ON
          (t.table_name=p.table_name AND t.table_schema=p.table_schema
              AND p.privilege_type='SELECT')
        JOIN information_schema.schemata s ON
          (s.schema_name=t.table_schema)
      WHERE (c.table_name=ANY(haystack_tables) OR haystack_tables='{}')
        AND (c.table_schema=ANY(haystack_schema) OR haystack_schema='{}')
        AND t.table_type='BASE TABLE'
  LOOP
    FOR rowctid IN
      EXECUTE format('SELECT ctid FROM %I.%I WHERE cast(%I as text)=%L',
       schemaname,
       tablename,
       columnname,
       needle
      )
    LOOP
      -- uncomment next line to get some progress report
      -- RAISE NOTICE 'hit in %.%', schemaname, tablename;
      RETURN NEXT;
    END LOOP;
 END LOOP;
END;
$$ language plpgsql;

See also the version on github based on the same principle but adding some speed and reporting improvements.

Examples of use in a test database:

  • Search in all tables within public schema:
select * from search_columns('foobar');
 schemaname | tablename | columnname | rowctid 
------------+-----------+------------+---------
 public     | s3        | usename    | (0,11)
 public     | s2        | relname    | (7,29)
 public     | w         | body       | (0,2)
(3 rows)
  • Search in a specific table:
 select * from search_columns('foobar','{w}');
 schemaname | tablename | columnname | rowctid 
------------+-----------+------------+---------
 public     | w         | body       | (0,2)
(1 row)
  • Search in a subset of tables obtained from a select:
select * from search_columns('foobar', array(select table_name::name from information_schema.tables where table_name like 's%'), array['public']);
 schemaname | tablename | columnname | rowctid 
------------+-----------+------------+---------
 public     | s2        | relname    | (7,29)
 public     | s3        | usename    | (0,11)
(2 rows)
  • Get a result row with the corresponding base table and and ctid:
select * from public.w where ctid='(0,2)';
 title |  body  |         tsv         
-------+--------+---------------------
 toto  | foobar | 'foobar':2 'toto':1

Variants

  • To test against a regular expression instead of strict equality, like grep, this part of the query:

    SELECT ctid FROM %I.%I WHERE cast(%I as text)=%L

    may be changed to:

    SELECT ctid FROM %I.%I WHERE cast(%I as text) ~ %L

  • For case insensitive comparisons, you could write:

    SELECT ctid FROM %I.%I WHERE lower(cast(%I as text)) = lower(%L)

Reload an iframe with jQuery

Reload an iframe with jQuery

make a link inside the iframe lets say with id = "reload" then use following code

$('#reload').click(function() {
    document.location.reload();
});

and you are good to go with all browsers.

Reload an iframe with HTML (no Java Script req.)

It have more simpler solution: which works without javaScript in (FF, Webkit)

just make an anchor inSide your iframe

   <a href="#" target="_SELF">Refresh Comments</a>

When you click this anchor it just refresh your iframe

But if you have parameter send to your iframe then do it as following.

  <a id="comnt-limit" href="?id=<?= $page_id?>" target="_SELF">Refresh Comments</a>

do not need any page url because -> target="_SELF" do it for you

Getting all selected checkboxes in an array

I didnt test it but it should work

<script type="text/javascript">
var selected = new Array();

$(document).ready(function() {

  $("input:checkbox[name=type]:checked").each(function() {
       selected.push($(this).val());
  });

});

</script>

TypeError: Missing 1 required positional argument: 'self'

You need to instantiate a class instance here.

Use

p = Pump()
p.getPumps()

Small example -

>>> class TestClass:
        def __init__(self):
            print("in init")
        def testFunc(self):
            print("in Test Func")


>>> testInstance = TestClass()
in init
>>> testInstance.testFunc()
in Test Func

"code ." Not working in Command Line for Visual Studio Code on OSX/Mac

EDIT: If this is happening on mint/ubuntu, it is likely because you installed vscode through the software manager. This will cause other problems during debugging. Instead install it using the .deb file on the vscode website.

If you really want to use the software manager, the solution below still works:

use find / -name code 2> /dev/null to find the path to the visual studio bin file. It should end in /extra/vscode/bin/code

If you're using the mint software manager, you might only find paths with a ridiculously long name in the middle like this:

".../stable/7a22830d9e8fbbdc9627e43e072005eef66c14d2a4dd19992427ef4de060186a/..."

Just replace the long part with "/active/"

Once you have it, create a sym link:

ln -s path_you_found/extra/vscode/bin/code /usr/local/bin/code

If you don't have the rights, or only want it to be accessible for yourself, simply add this line to your .bashrc / .zshrc:

export PATH="$PATH:path_you_found/extra/vscode/bin/

Note that I removed the 'code' filename at the end

Create a menu Bar in WPF?

<Container>
    <Menu>
        <MenuItem Header="File">
            <MenuItem Header="New">
               <MenuItem Header="File1"/>
               <MenuItem Header="File2"/>
               <MenuItem Header="File3"/>
            </MenuItem>
            <MenuItem Header="Open"/>
            <MenuItem Header="Save"/>
        </MenuItem>
    </Menu>
</Container>

How to make primary key as autoincrement for Room Persistence lib

Annotate your Entity class with the code below.

In Java:

@PrimaryKey(autoGenerate = true)
private int id;

In Kotlin:

@PrimaryKey(autoGenerate = true)
var id: Int

Room will then auto-generate and auto-increment the id field.

How do I get the difference between two Dates in JavaScript?

Depending on your needs, this function will calculate the difference between the 2 days, and return a result in days decimal.

// This one returns a signed decimal. The sign indicates past or future.

this.getDateDiff = function(date1, date2) {
    return (date1.getTime() - date2.getTime()) / (1000 * 60 * 60 * 24);
}

// This one always returns a positive decimal. (Suggested by Koen below)

this.getDateDiff = function(date1, date2) {
    return Math.abs((date1.getTime() - date2.getTime()) / (1000 * 60 * 60 * 24));
}

Why does git revert complain about a missing -m option?

Say the other guy created bar on top of foo, but you created baz in the meantime and then merged, giving a history of

$ git lola
*   2582152 (HEAD, master) Merge branch 'otherguy'
|\  
| * c7256de (otherguy) bar
* | b7e7176 baz
|/  
* 9968f79 foo

Note: git lola is a non-standard but useful alias.

No dice with git revert:

$ git revert HEAD
fatal: Commit 2582152... is a merge but no -m option was given.

Charles Bailey gave an excellent answer as usual. Using git revert as in

$ git revert --no-edit -m 1 HEAD
[master e900aad] Revert "Merge branch 'otherguy'"
 0 files changed, 0 insertions(+), 0 deletions(-)
 delete mode 100644 bar

effectively deletes bar and produces a history of

$ git lola
* e900aad (HEAD, master) Revert "Merge branch 'otherguy'"
*   2582152 Merge branch 'otherguy'
|\  
| * c7256de (otherguy) bar
* | b7e7176 baz
|/  
* 9968f79 foo

But I suspect you want to throw away the merge commit:

$ git reset --hard HEAD^
HEAD is now at b7e7176 baz

$ git lola
* b7e7176 (HEAD, master) baz
| * c7256de (otherguy) bar
|/  
* 9968f79 foo

As documented in the git rev-parse manual

<rev>^, e.g. HEAD^, v1.5.1^0
A suffix ^ to a revision parameter means the first parent of that commit object. ^<n> means the n-th parent (i.e. <rev>^ is equivalent to <rev>^1). As a special rule, <rev>^0 means the commit itself and is used when <rev> is the object name of a tag object that refers to a commit object.

so before invoking git reset, HEAD^ (or HEAD^1) was b7e7176 and HEAD^2 was c7256de, i.e., respectively the first and second parents of the merge commit.

Be careful with git reset --hard because it can destroy work.

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

Here is what I came up with after reading Tony Wong's comment:

public class DebugExampleTwo extends BaseActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addFragment(android.R.id.content,
                    new DebugExampleTwoFragment(),
                    DebugExampleTwoFragment.FRAGMENT_TAG);
    }

}

...

public abstract class BaseActivity extends Activity {

    protected void addFragment(@IdRes int containerViewId,
                               @NonNull Fragment fragment,
                               @NonNull String fragmentTag) {
        getSupportFragmentManager()
                .beginTransaction()
                .add(containerViewId, fragment, fragmentTag)
                .disallowAddToBackStack()
                .commit();
    }

    protected void replaceFragment(@IdRes int containerViewId,
                                   @NonNull Fragment fragment,
                                   @NonNull String fragmentTag,
                                   @Nullable String backStackStateName) {
        getSupportFragmentManager()
                .beginTransaction()
                .replace(containerViewId, fragment, fragmentTag)
                .addToBackStack(backStackStateName)
                .commit();
    }

}

...

public class DebugExampleTwoFragment extends Fragment {

    public static final String FRAGMENT_TAG = 
        BuildConfig.APPLICATION_ID + ".DEBUG_EXAMPLE_TWO_FRAGMENT_TAG";

    // ...

}

Kotlin

If you are using Kotlin make sure to take a look at what the Kotlin extensions by Google provide or just write your own.

Unexpected token ILLEGAL in webkit

Also for the Google-fodder: check in your text editor whether the .js file is saved as Unicode and consider setting it to ANSI; also check if the linefeeds are set to DOS and consider switching them to Unix (depending on your server, of course).

How do I reference a local image in React?

import React from "react";   
import image from './img/one.jpg';

class Image extends React.Component{
  render(){
    return(
      <img className='profile-image' alt='icon' src={image}/>
   );
  }
}

export default Image

Node.js - get raw request body using Express

Use body-parser Parse the body with what it will be:

app.use(bodyParser.text());

app.use(bodyParser.urlencoded());

app.use(bodyParser.raw());

app.use(bodyParser.json());

ie. If you are supposed to get raw text file, run .text().

Thats what body-parser currently supports

Creating stored procedure with declare and set variables

I assume you want to pass the Order ID in. So:

CREATE PROCEDURE [dbo].[Procedure_Name]
(
    @OrderID INT
) AS
BEGIN
    Declare @OrderItemID AS INT
    DECLARE @AppointmentID AS INT
    DECLARE @PurchaseOrderID AS INT
    DECLARE @PurchaseOrderItemID AS INT
    DECLARE @SalesOrderID AS INT
    DECLARE @SalesOrderItemID AS INT

    SET @OrderItemID = (SELECT OrderItemID FROM [OrderItem] WHERE OrderID = @OrderID)
    SET @AppointmentID = (SELECT AppoinmentID FROM [Appointment] WHERE OrderID = @OrderID)
    SET @PurchaseOrderID = (SELECT PurchaseOrderID FROM [PurchaseOrder] WHERE OrderID = @OrderID)
END

How can I get a specific number child using CSS?

For IE 7 & 8 (and other browsers without CSS3 support not including IE6) you can use the following to get the 2nd and 3rd children:

2nd Child:

td:first-child + td

3rd Child:

td:first-child + td + td

Then simply add another + td for each additional child you wish to select.

If you want to support IE6 that can be done too! You simply need to use a little javascript (jQuery in this example):

$(function() {
    $('td:first-child').addClass("firstChild");
    $(".table-class tr").each(function() {
        $(this).find('td:eq(1)').addClass("secondChild");
        $(this).find('td:eq(2)').addClass("thirdChild");
    });
});

Then in your css you simply use those class selectors to make whatever changes you like:

table td.firstChild { /*stuff here*/ }
table td.secondChild { /*stuff to apply to second td in each row*/ }

Detect rotation of Android phone in the browser with JavaScript

two-bit-fool's excellent answer provides all the background, but let me attempt a concise, pragmatic summary of how to handle orientation changes across iOS and Android:

  • If you only care about window dimensions (the typical scenario) - and not about the specific orientation:
    • Handle the resize event only.
    • In your handler, act on window.innerWidth and window.InnerHeight only.
    • Do NOT use window.orientation - it won't be current on iOS.
  • If you DO care about the specific orientation:
    • Handle only the resize event on Android, and only the orientationchange event on iOS.
    • In your handler, act on window.orientation (and window.innerWidth and window.InnerHeight)

These approaches offer slight benefits over remembering the previous orientation and comparing:

  • the dimensions-only approach also works while developing on desktop browsers that can otherwise simulate mobile devices, e.g., Chrome 23. (window.orientation is not available on desktop browsers).
  • no need for a global/anonymous-file-level-function-wrapper-level variable.

How to find the extension of a file in C#?

Path.GetExtension

string myFilePath = @"C:\MyFile.txt";
string ext = Path.GetExtension(myFilePath);
// ext would be ".txt"

Loading inline content using FancyBox

The way I figured this out was going through the example index.html/style.css that comes packaged with the Fancybox installation.

If you view the code that is used for the demo website and basically copy/paste, you'll be fine.

To get an inline Fancybox working, you will need to have this code present in your index.html file:

  <head>
    <link href="./fancybox/jquery.fancybox-1.3.4.css" rel="stylesheet" type="text/css" media="screen" />
    <script>!window.jQuery && document.write('<script src="jquery-1.4.3.min.js"><\/script>');</script>
    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js"></script>
    <script type="text/javascript" src="./fancybox/jquery.fancybox-1.3.4.pack.js"></script>
    <script type="text/javascript">
    $(document).ready(function() {

    $("#various1").fancybox({
            'titlePosition'     : 'inside',
            'transitionIn'      : 'none',
            'transitionOut'     : 'none'
        });
    });
    </script>
  </head>

 <body>

    <a id="various1" href="#inline1" title="Put a title here">Name of Link Here</a>
    <div style="display: none;">
        <div id="inline1" style="width:400px;height:100px;overflow:auto;">
                   Write whatever text you want right here!!
        </div>
    </div> 

</body>

Remember to be precise about what folders your script files are placed in and where you are pointing to in the Head tag; they must correspond.

Chrome, Javascript, window.open in new tab

You can use this code to open in new tab..

function openWindow( url )
{
  window.open(url, '_blank');
  window.focus();
}

I got it from stackoverflow..

How to semantically add heading to a list

Your first option is the good one. It's the least problematic one and you've already found the correct reasons why you couldn't use the other options.

By the way, your heading IS explicitly associated with the <ul> : it's right before the list! ;)

edit: Steve Faulkner, one of the editors of W3C HTML5 and 5.1 has sketched out a definition of an lt element. That's an unofficial draft that he'll discuss for HTML 5.2, nothing more yet.

len() of a numpy array in python

You can transpose the array if you want to get the length of the other dimension.

len(np.array([[2,3,1,0], [2,3,1,0], [3,2,1,1]]).T)

Array versus List<T>: When to use which?

If I know exactly how many elements I'm going to need, say I need 5 elements and only ever 5 elements then I use an array. Otherwise I just use a List<T>.

How to place a div on the right side with absolute position

Can you try the following:

float: right;

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

VBA uses a garbage collector which is implemented by reference counting.

There can be multiple references to a given object (for example, Dim aw = ActiveWorkbook creates a new reference to Active Workbook), so the garbage collector only cleans up an object when it is clear that there are no other references. Setting to Nothing is an explicit way of decrementing the reference count. The count is implicitly decremented when you exit scope.

Strictly speaking, in modern Excel versions (2010+) setting to Nothing isn't necessary, but there were issues with older versions of Excel (for which the workaround was to explicitly set)

Remove padding or margins from Google Charts

I arrived here like most people with this same issue, and left shocked that none of the answer even remotely worked.

For anyone interested, here is the actual solution:

... //rest of options
width: '100%',
height: '350',
chartArea:{
    left:5,
    top: 20,
    width: '100%',
    height: '350',
}
... //rest of options

The key here has nothing to do with the "left" or "top" values. But rather that the:

Dimensions of both the chart and chart-area are SET and set to the SAME VALUE

As an amendment to my answer. The above will indeed solve the "excessive" padding/margin/whitespace problem. However, if you wish to include axes labels and/or a legend you will need to reduce the height & width of the chart area so something slightly below the outer width/height. This will "tell" the chart API that there is sufficient room to display these properties. Otherwise it will happily exclude them.

How can I create a link to a local file on a locally-run web page?

back to 2017:

use URL.createObjectURL( file ) to create local link to file system that user select;

don't forgot to free memory by using URL.revokeObjectURL()

How to join multiple collections with $lookup in mongodb

According to the documentation, $lookup can join only one external collection.

What you could do is to combine userInfo and userRole in one collection, as provided example is based on relational DB schema. Mongo is noSQL database - and this require different approach for document management.

Please find below 2-step query, which combines userInfo with userRole - creating new temporary collection used in last query to display combined data. In last query there is an option to use $out and create new collection with merged data for later use.

create collections

db.sivaUser.insert(
{    
    "_id" : ObjectId("5684f3c454b1fd6926c324fd"),
        "email" : "[email protected]",
        "userId" : "AD",
        "userName" : "admin"
})

//"userinfo"
db.sivaUserInfo.insert(
{
    "_id" : ObjectId("56d82612b63f1c31cf906003"),
    "userId" : "AD",
    "phone" : "0000000000"
})

//"userrole"
db.sivaUserRole.insert(
{
    "_id" : ObjectId("56d82612b63f1c31cf906003"),
    "userId" : "AD",
    "role" : "admin"
})

"join" them all :-)

db.sivaUserInfo.aggregate([
    {$lookup:
        {
           from: "sivaUserRole",
           localField: "userId",
           foreignField: "userId",
           as: "userRole"
        }
    },
    {
        $unwind:"$userRole"
    },
    {
        $project:{
            "_id":1,
            "userId" : 1,
            "phone" : 1,
            "role" :"$userRole.role"
        }
    },
    {
        $out:"sivaUserTmp"
    }
])


db.sivaUserTmp.aggregate([
    {$lookup:
        {
           from: "sivaUser",
           localField: "userId",
           foreignField: "userId",
           as: "user"
        }
    },
    {
        $unwind:"$user"
    },
    {
        $project:{
            "_id":1,
            "userId" : 1,
            "phone" : 1,
            "role" :1,
            "email" : "$user.email",
            "userName" : "$user.userName"
        }
    }
])

Sending email from Azure

I know this is an old post but I've just signed up for Azure and I get 25,000 emails a month for free via SendGrid. These instructions are excellent, I was up and running in minutes:

How to Send Email Using SendGrid with Azure

Azure customers can unlock 25,000 free emails each month.

How can I display two div in one line via css inline property

You don't need to use display:inline to achieve this:

.inline { 
    border: 1px solid red;
    margin:10px;
    float:left;/*Add float left*/
    margin :10px;
}

You can use float-left.

Using float:left is best way to place multiple div elements in one line. Why? Because inline-block does have some problem when is viewed in IE older versions.

fiddle

How to set default values for Angular 2 component properties?

Here is the best solution for this. (ANGULAR All Version)

Addressing solution: To set a default value for @Input variable. If no value passed to that input variable then It will take the default value.

I have provided solution for this kind of similar question. You can find the full solution from here

export class CarComponent implements OnInit {
  private _defaultCar: car = {
    // default isCar is true
    isCar: true,
    // default wheels  will be 4
    wheels: 4
  };

  @Input() newCar: car = {};

  constructor() {}

  ngOnInit(): void {

   // this will concate both the objects and the object declared later (ie.. ...this.newCar )
   // will overwrite the default value. ONLY AND ONLY IF DEFAULT VALUE IS PRESENT

    this.newCar = { ...this._defaultCar, ...this.newCar };
   //  console.log(this.newCar);
  }
}

JavaScript: Parsing a string Boolean value?

last but not least, a simple and efficient way to do it with a default value :

ES5

function parseBool(value, defaultValue) {
    return (value == 'true' || value == 'false' || value === true || value === false) && JSON.parse(value) || defaultValue;
}

ES6 , a shorter one liner

const parseBool = (value, defaultValue) => ['true', 'false', true, false].includes(value) && JSON.parse(value) || defaultValue

JSON.parse is efficient to parse booleans

After Spring Boot 2.0 migration: jdbcUrl is required with driverClassName

This happened to me because I was using:

app.datasource.url=jdbc:mysql://localhost/test

When I replaced url by jdbc-url then it worked:

app.datasource.jdbc-url=jdbc:mysql://localhost/test

Equation for testing if a point is inside a circle

In general, x and y must satisfy (x - center_x)^2 + (y - center_y)^2 < radius^2.

Please note that points that satisfy the above equation with < replaced by == are considered the points on the circle, and the points that satisfy the above equation with < replaced by > are considered the outside the circle.

Perform commands over ssh with Python

Below example, incase if you want user inputs for hostname,username,password and port no.

  import paramiko

  ssh = paramiko.SSHClient()

  ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())



  def details():

  Host = input("Enter the Hostname: ")

  Port = input("Enter the Port: ")

  User = input("Enter the Username: ")

  Pass = input("Enter the Password: ")

  ssh.connect(Host, Port, User, Pass, timeout=2)

  print('connected')

  stdin, stdout, stderr = ssh.exec_command("")

  stdin.write('xcommand SystemUnit Boot Action: Restart\n')

  print('success')

  details()

Simple CSS Animation Loop – Fading In & Out "Loading" Text

well looking for a simpler variation I found this:

it's truly smart, and I guess you might want to add other browsers variations too although it worked for me both on Chrome and Firefox.

demo and credit => http://codepen.io/Ahrengot/pen/bKdLC

_x000D_
_x000D_
@keyframes fadeIn { _x000D_
  from { opacity: 0; } _x000D_
}_x000D_
_x000D_
.animate-flicker {_x000D_
    animation: fadeIn 1s infinite alternate;_x000D_
}
_x000D_
<h2 class="animate-flicker">Jump in the hole!</h2>
_x000D_
_x000D_
_x000D_

How to compare different branches in Visual Studio Code

It's now possible by using the githistory extension.

Here's a small trick though: You can compare the latest commits from each branch and that would be the same as comparing two branches side by side or creating a PR.

Here's how to do that using githistory extension:

  1. Open githistory
  2. Pick the latest commit from your current branch by clicking on "Git Commit Icon" → (Usually it should be latest commit it the list). From the opened dropdown menu click on "Select this commit".
  3. Pick the latest commit from the branch you want to compare to by clicking "Git Commit Icon".
  4. As a result, the dropdown should appear with a few options → Select the last option that says "Compare with SHA" and you'll see the diff.

Arrays.fill with multidimensional array in Java

Don't we all sometimes wish there was a
<T>void java.util.Arrays.deepFill(T[]…multiDimensional). Problems start with
Object threeByThree[][] = new Object[3][3];
threeByThree[1] = null; and
threeByThree[2][1] = new int[]{42}; being perfectly legal.
(If only Object twoDim[]final[] was legal and well defined…)
(Using one of the public methods from below keeps loops from the calling source code.
If you insist on using no loops at all, substitute the loops and the call to Arrays.fill()(!) using recursion.)

/** Fills matrix {@code m} with {@code value}.
 * @return {@code m}'s dimensionality.
 * @throws java.lang.ArrayStoreException if the component type
 *  of a subarray of non-zero length at the bottom level
 *  doesn't agree with {@code value}'s type. */
public static <T>int deepFill(Object[] m, T value) {
    Class<?> components; 
    if (null == m ||
        null == (components = m.getClass().getComponentType()))
        return 0;
    int dim = 0;
    do
        dim++;
    while (null != (components = components.getComponentType()));
    filler((Object[][])m, value, dim);
    return dim;
}
/** Fills matrix {@code m} with {@code value}.
 * @throws java.lang.ArrayStoreException if the component type
 *  of a subarray of non-zero length at level {@code dimensions}
 *  doesn't agree with {@code value}'s type. */
public static <T>void fill(Object[] m, T value, int dimensions) {
    if (null != m)
        filler(m, value, dimensions);
}

static <T>void filler(Object[] m, T value, int toGo) {
    if (--toGo <= 0)
        java.util.Arrays.fill(m, value);
    else
        for (Object[] subArray : (Object[][])m)
            if (null != subArray)
                filler(subArray, value, toGo);
}

Resolve build errors due to circular dependency amongst classes

I once solved this kind of problem by moving all inlines after the class definition and putting the #include for the other classes just before the inlines in the header file. This way one make sure all definitions+inlines are set prior the inlines are parsed.

Doing like this makes it possible to still have a bunch of inlines in both(or multiple) header files. But it's necessary to have include guards.

Like this

// File: A.h
#ifndef __A_H__
#define __A_H__
class B;
class A
{
    int _val;
    B *_b;
public:
    A(int val);
    void SetB(B *b);
    void Print();
};

// Including class B for inline usage here 
#include "B.h"

inline A::A(int val) : _val(val)
{
}

inline void A::SetB(B *b)
{
    _b = b;
    _b->Print();
}

inline void A::Print()
{
    cout<<"Type:A val="<<_val<<endl;
}

#endif /* __A_H__ */

...and doing the same in B.h

What is the difference between Java RMI and RPC?

RPC is C based, and as such it has structured programming semantics, on the other side, RMI is a Java based technology and it's object oriented.

With RPC you can just call remote functions exported into a server, in RMI you can have references to remote objects and invoke their methods, and also pass and return more remote object references that can be distributed among many JVM instances, so it's much more powerful.

RMI stands out when the need to develop something more complex than a pure client-server architecture arises. It's very easy to spread out objects over a network enabling all the clients to communicate without having to stablish individual connections explicitly.

Add leading zeroes/0's to existing Excel values to certain length

Even this will work nicely

REPT(0,2-LEN(F2)&F2

where 2 is total number of digits, for 0 ~ 9 -> it will display 00 to 09 rest nothing will be added.

How do I align a label and a textarea?

Align the text area box to the label, not the label to the text area,

label {
    width: 180px;
    display: inline-block;
}

textarea{
    vertical-align: middle;
}

<label for="myfield">Label text</label><textarea id="myfield" rows="5" cols="30"></textarea>

linux execute command remotely

I think this article explains well:

Running Commands on a Remote Linux / UNIX Host

Google is your best friend ;-)

How to retrieve a module's path?

This was trivial.

Each module has a __file__ variable that shows its relative path from where you are right now.

Therefore, getting a directory for the module to notify it is simple as:

os.path.dirname(__file__)

Why use a ReentrantLock if one can use synchronized(this)?

You can use reentrant locks with a fairness policy or timeout to avoid thread starvation. You can apply a thread fairness policy. it will help avoid a thread waiting forever to get to your resources.

private final ReentrantLock lock = new ReentrantLock(true);
//the param true turns on the fairness policy. 

The "fairness policy" picks the next runnable thread to execute. It is based on priority, time since last run, blah blah

also, Synchronize can block indefinitely if it cant escape the block. Reentrantlock can have timeout set.

Reset textbox value in javascript

I know this is an old post, but this may help clarify:

$('#searchField')
    .val('')// [property value] e.g. what is visible / will be submitted
    .attr('value', '');// [attribute value] e.g. <input value="preset" ...

Changing [attribute value] has no effect if there is a [property value]. (user || js altered input)

How to truncate a foreign key constrained table?

Easy if you are using phpMyAdmin.

Just uncheck Enable foreign key checks option under SQL tab and run TRUNCATE <TABLE_NAME>

enter image description here

Get index of element as child relative to parent

$("#wizard li").click(function () {
    console.log( $(this).index() );
});

However rather than attaching one click handler for each list item it is better (performance wise) to use delegate which would look like this:

$("#wizard").delegate('li', 'click', function () {
    console.log( $(this).index() );
});

In jQuery 1.7+, you should use on. The below example binds the event to the #wizard element, working like a delegate event:

$("#wizard").on("click", "li", function() {
    console.log( $(this).index() );
});

How to split (chunk) a Ruby array into parts of X elements?

If you're using rails you can also use in_groups_of:

foo.in_groups_of(3)

PHP date time greater than today

You are not comparing dates. You are comparing strings. In the world of string comparisons, 09/17/2015 > 01/02/2016 because 09 > 01. You need to either put your date in a comparable string format or compare DateTime objects which are comparable.

<?php
 $date_now = date("Y-m-d"); // this format is string comparable

if ($date_now > '2016-01-02') {
    echo 'greater than';
}else{
    echo 'Less than';
}

Demo

Or

<?php
 $date_now = new DateTime();
 $date2    = new DateTime("01/02/2016");

if ($date_now > $date2) {
    echo 'greater than';
}else{
    echo 'Less than';
}

Demo

Merge 2 DataTables and store in a new one

The Merge method takes the values from the second table and merges them in with the first table, so the first will now hold the values from both.

If you want to preserve both of the original tables, you could copy the original first, then merge:

dtAll = dtOne.Copy();
dtAll.Merge(dtTwo);

Ignore files that have already been committed to a Git repository

There is another suggestion maybe for the slow guys like me =) Put the .gitignore file into your repository root not in .git folder. Cheers!

Can I embed a custom font in an iPhone application?

Maybe the author forgot to give the font a Mac FOND name?

  1. Open the font in FontForge then go to Element>Font Info
  2. There is a "Mac" Option where you can set the FOND name.
  3. Under File>Export Font you can create a new ttf

You could also give the "Apple" option in the export dialog a try.

DISCLAIMER: I'm not a IPhone developer!

how to overwrite css style

Yes, you can indeed. There are three ways of achieving this that I can think of.

  1. Add inline styles to the elements.
  2. create and append a new <style> element, and add the text to override this style to it.
  3. Modify the css rule itself.

Notes:

  1. is somewhat messy and adds to the parsing the browser needs to do to render.
  2. perhaps my favourite method
  3. Not cross-browser, some browsers like it done one way, others a different way, while the remainder just baulk at the idea.

How to write trycatch in R

R uses functions for implementing try-catch block:

The syntax somewhat looks like this:

result = tryCatch({
    expr
}, warning = function(warning_condition) {
    warning-handler-code
}, error = function(error_condition) {
    error-handler-code
}, finally={
    cleanup-code
})

In tryCatch() there are two ‘conditions’ that can be handled: ‘warnings’ and ‘errors’. The important thing to understand when writing each block of code is the state of execution and the scope. @source

how to call scalar function in sql server 2008

Your syntax is for table valued function which return a resultset and can be queried like a table. For scalar function do

 select  dbo.fun_functional_score('01091400003') as [er]

How to verify if $_GET exists?

You can use isset function:

if(isset($_GET['id'])) {
    // id index exists
}

You can create a handy function to return default value if index doesn't exist:

function Get($index, $defaultValue) {
    return isset($_GET[$index]) ? $_GET[$index] : $defaultValue;
}

// prints "invalid id" if $_GET['id'] is not set
echo Get('id', 'invalid id');

You can also try to validate it at the same time:

function GetInt($index, $defaultValue) {
    return isset($_GET[$index]) && ctype_digit($_GET[$index])
            ? (int)$_GET[$index] 
            : $defaultValue;
}

// prints 0 if $_GET['id'] is not set or is not numeric
echo GetInt('id', 0);

How to get the url parameters using AngularJS

I found solution how to use $location.search() to get parameter from URL

first in URL u need put syntax " # " before parameter like this example

"http://www.example.com/page#?key=value"

and then in your controller u put $location in function and use $location.search() to get URL parameter for

.controller('yourController', ['$scope', function($scope, $location) {

     var param1 = $location.search().param1; //Get parameter from URL

}]);

Rotating a Div Element in jQuery

To rotate a DIV Make use of WebkitTransform / -moz-transform: rotate(Xdeg).

This will not work in IE. The Raphael library does work with IE and it does rotation. I believe it uses canvases

If you want to animate the rotation, you can use a recursive setTimeout()

You could probably even do part of a spin with jQuery's .animate()

Make sure that you consider the width of your element. If rotate an that has a larger width than its visible content, you'll get funny results. However you can narrow the widths of elements, and then rotate them.

Here is a simply jQuery snippet that rotates the elements in a jQuery object. Rotatation can be started and stopped:

$(function() {
    var $elie = $(selectorForElementsToRotate);
    rotate(0);
    function rotate(degree) {

          // For webkit browsers: e.g. Chrome
        $elie.css({ WebkitTransform: 'rotate(' + degree + 'deg)'});
          // For Mozilla browser: e.g. Firefox
        $elie.css({ '-moz-transform': 'rotate(' + degree + 'deg)'});

          // Animate rotation with a recursive call
        setTimeout(function() { rotate(++degree); },5);
    }
});

jsFiddle example

Note:
Taking the degree and increasing it, will rotate the image clockwise. Decreasing the degree of rotation will rotate the image counter clockwise.

How to redirect output of systemd service to a file

Assume logs are already put to stdout/stderr, and have systemd unit's log in /var/log/syslog

journalctl -u unitxxx.service

Jun 30 13:51:46 host unitxxx[1437]: time="2018-06-30T11:51:46Z" level=info msg="127.0.0.1
Jun 30 15:02:15 host unitxxx[1437]: time="2018-06-30T13:02:15Z" level=info msg="127.0.0.1
Jun 30 15:33:02 host unitxxx[1437]: time="2018-06-30T13:33:02Z" level=info msg="127.0.0.1
Jun 30 15:56:31 host unitxxx[1437]: time="2018-06-30T13:56:31Z" level=info msg="127.0.0.1

Config rsyslog (System Logging Service)

# Create directory for log file
mkdir /var/log/unitxxx

# Then add config file /etc/rsyslog.d/unitxxx.conf

if $programname == 'unitxxx' then /var/log/unitxxx/unitxxx.log
& stop

Restart rsyslog

systemctl restart rsyslog.service

Ruby - ignore "exit" in code

One hackish way to define an exit method in context:

class Bar; def exit; end; end 

This works because exit in the initializer will be resolved as self.exit1. In addition, this approach allows using the object after it has been created, as in: b = B.new.

But really, one shouldn't be doing this: don't have exit (or even puts) there to begin with.

(And why is there an "infinite" loop and/or user input in an intiailizer? This entire problem is primarily the result of poorly structured code.)


1 Remember Kernel#exit is only a method. Since Kernel is included in every Object, then it's merely the case that exit normally resolves to Object#exit. However, this can be changed by introducing an overridden method as shown - nothing fancy.

NuGet: 'X' already has a dependency defined for 'Y'

  1. Go to the link https://www.nuget.org/packages/ClosedXML/0.64.0
  2. Search your NuGet packages
  3. See the all version of related packages
  4. Install the lower version of packages

List of ANSI color escape sequences

How about:

ECMA-48 - Control Functions for Coded Character Sets, 5th edition (June 1991) - A standard defining the color control codes, that is apparently supported also by xterm.

SGR 38 and 48 were originally reserved by ECMA-48, but were fleshed out a few years later in a joint ITU, IEC, and ISO standard, which comes in several parts and which (amongst a whole lot of other things) documents the SGR 38/48 control sequences for direct colour and indexed colour:

There's a column for xterm in this table on the Wikipedia page for ANSI escape codes

Print "\n" or newline characters as part of the output on terminal

If you're in control of the string, you could also use a 'Raw' string type:

>>> string = r"abcd\n"
>>> print(string)
abcd\n

Controlling Maven final name of jar artifact

@Maxim
try this...

pom.xml

 <groupId>org.opensource</groupId>
 <artifactId>base</artifactId>
 <version>1.0.0.SNAPSHOT</version>

  ..............
<properties>
    <my.version>4.0.8.8</my.version>
</properties>

<build>
    <finalName>my-base-project</finalName>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-install-plugin</artifactId>
            <version>2.3.1</version>
            <executions>
                <execution>
                    <goals>
                        <goal>install-file</goal>
                    </goals>
                    <phase>install</phase>
                    <configuration>
                        <file>${project.build.finalName}.${project.packaging}</file>
                        <generatePom>false</generatePom>
                        <pomFile>pom.xml</pomFile>
                        <version>${my.version}</version>
                    </configuration>
                </execution>
            </executions>
        </plugin>
</plugins>
</build>

Commnad mvn clean install

Output

[INFO] --- maven-jar-plugin:2.3.1:jar (default-jar) @ base ---
[INFO] Building jar: D:\dev\project\base\target\my-base-project.jar
[INFO]
[INFO] --- maven-install-plugin:2.3.1:install (default-install) @ base ---
[INFO] Installing D:\dev\project\base\target\my-base-project.jar to H:\dev\.m2\repository\org\opensource\base\1.0.0.SNAPSHOT\base-1.0.0.SNAPSHOT.jar
[INFO] Installing D:\dev\project\base\pom.xml to H:\dev\.m2\repository\org\opensource\base\1.0.0.SNAPSHOT\base-1.0.0.SNAPSHOT.pom
[INFO]
[INFO] --- maven-install-plugin:2.3.1:install-file (default) @ base ---
[INFO] Installing D:\dev\project\base\my-base-project.jar to H:\dev\.m2\repository\org\opensource\base\4.0.8.8\base-4.0.8.8.jar
[INFO] Installing D:\dev\project\base\pom.xml to H:\dev\.m2\repository\org\opensource\base\4.0.8.8\base-4.0.8.8.pom
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------


Reference

typescript - cloning object

For a simple clone of the hole object's content, I simply stringify and parse the instance :

let cloneObject = JSON.parse(JSON.stringify(objectToClone))

Whereas I change data in objectToClone tree, there is no change in cloneObject. That was my requierement.

Hope it help

Dynamically Add Variable Name Value Pairs to JSON Object

in Javascript.

    var myObject = { "name" : "john" };
    // { "name" : "john" };
    myObject.gender = "male";
    // { "name" : "john", "gender":"male"};

What does 'URI has an authority component' mean?

An authority is a portion of a URI. Your error suggests that it was not expecting one. The authority section is shown below, it is what is known as the website part of the url.

From RFC3986 on URIs:

The following is an example URI and its component parts:

     foo://example.com:8042/over/there?name=ferret#nose
     \_/   \______________/\_________/ \_________/ \__/
      |           |            |            |        |
   scheme     authority       path        query   fragment
      |   _____________________|__
     / \ /                        \
     urn:example:animal:ferret:nose

So there are two formats, one with an authority and one not. Regarding slashes:

"When authority is not present, the path cannot begin with two slash
characters ("//")."

Source: https://tools.ietf.org/rfc/rfc3986.txt (search for text 'authority is not present, the path cannot begin with two slash')

Where is the documentation for the values() method of Enum?

Run this

    for (Method m : sex.class.getDeclaredMethods()) {
        System.out.println(m);
    }

you will see

public static test.Sex test.Sex.valueOf(java.lang.String)
public static test.Sex[] test.Sex.values()

These are all public methods that "sex" class has. They are not in the source code, javac.exe added them

Notes:

  1. never use sex as a class name, it's difficult to read your code, we use Sex in Java

  2. when facing a Java puzzle like this one, I recommend to use a bytecode decompiler tool (I use Andrey Loskutov's bytecode outline Eclispe plugin). This will show all what's inside a class

Adding and using header (HTTP) in nginx

You can use upstream headers (named starting with $http_) and additional custom headers. For example:

add_header X-Upstream-01 $http_x_upstream_01;
add_header X-Hdr-01  txt01;

next, go to console and make request with user's header:

curl -H "X-Upstream-01: HEADER1" -I http://localhost:11443/

the response contains X-Hdr-01, seted by server and X-Upstream-01, seted by client:

HTTP/1.1 200 OK
Server: nginx/1.8.0
Date: Mon, 30 Nov 2015 23:54:30 GMT
Content-Type: text/html;charset=UTF-8
Connection: keep-alive
X-Hdr-01: txt01
X-Upstream-01: HEADER1

Predict() - Maybe I'm not understanding it

instead of newdata you are using newdate in your predict code, verify once. and just use Coupon$estimate <- predict(model, Coupon) It will work.

How to remove the left part of a string?

How about..

>>> line = r'path=c:\path'
>>> line.partition('path=')
('', 'path=', 'c:\\path')

This triplet is the head, separator, and tail.

Can I update a JSF component from a JSF backing bean method?

Using standard JSF API, add the client ID to PartialViewContext#getRenderIds().

FacesContext.getCurrentInstance().getPartialViewContext().getRenderIds().add("foo:bar");

Using PrimeFaces specific API, use PrimeFaces.Ajax#update().

PrimeFaces.current().ajax().update("foo:bar");

Or if you're not on PrimeFaces 6.2+ yet, use RequestContext#update().

RequestContext.getCurrentInstance().update("foo:bar");

If you happen to use JSF utility library OmniFaces, use Ajax#update().

Ajax.update("foo:bar");

Regardless of the way, note that those client IDs should represent absolute client IDs which are not prefixed with the NamingContainer separator character like as you would do from the view side on.

python date of the previous month

For someone who got here and looking to get both the first and last day of the previous month:

from datetime import date, timedelta

last_day_of_prev_month = date.today().replace(day=1) - timedelta(days=1)

start_day_of_prev_month = date.today().replace(day=1) - timedelta(days=last_day_of_prev_month.day)

# For printing results
print("First day of prev month:", start_day_of_prev_month)
print("Last day of prev month:", last_day_of_prev_month)

Output:

First day of prev month: 2019-02-01
Last day of prev month: 2019-02-28

What's the difference between SoftReference and WeakReference in Java?

From Understanding Weak References, by Ethan Nicholas:

Weak references

A weak reference, simply put, is a reference that isn't strong enough to force an object to remain in memory. Weak references allow you to leverage the garbage collector's ability to determine reachability for you, so you don't have to do it yourself. You create a weak reference like this:

WeakReference weakWidget = new WeakReference(widget);

and then elsewhere in the code you can use weakWidget.get() to get the actual Widget object. Of course the weak reference isn't strong enough to prevent garbage collection, so you may find (if there are no strong references to the widget) that weakWidget.get() suddenly starts returning null.

...

Soft references

A soft reference is exactly like a weak reference, except that it is less eager to throw away the object to which it refers. An object which is only weakly reachable (the strongest references to it are WeakReferences) will be discarded at the next garbage collection cycle, but an object which is softly reachable will generally stick around for a while.

SoftReferences aren't required to behave any differently than WeakReferences, but in practice softly reachable objects are generally retained as long as memory is in plentiful supply. This makes them an excellent foundation for a cache, such as the image cache described above, since you can let the garbage collector worry about both how reachable the objects are (a strongly reachable object will never be removed from the cache) and how badly it needs the memory they are consuming.

And Peter Kessler added in a comment:

The Sun JRE does treat SoftReferences differently from WeakReferences. We attempt to hold on to object referenced by a SoftReference if there isn't pressure on the available memory. One detail: the policy for the "-client" and "-server" JRE's are different: the -client JRE tries to keep your footprint small by preferring to clear SoftReferences rather than expand the heap, whereas the -server JRE tries to keep your performance high by preferring to expand the heap (if possible) rather than clear SoftReferences. One size does not fit all.

NavigationBar bar, tint, and title text color in iOS 8

If you want to set the tint color and bar color for the entire app, the following code can be added to AppDelegate.swift in

 func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        // Override point for customization after application launch.

    var navigationBarAppearace = UINavigationBar.appearance()

    navigationBarAppearace.tintColor = UIColor(red:1.00, green:1.00, blue:1.00, alpha:1.0)
    navigationBarAppearace.barTintColor = UIColor(red:0.76, green:0.40, blue:0.40, alpha:1.0)
    navigationBarAppearace.titleTextAttributes = [NSForegroundColorAttributeName: UIColor.white]
    return true
`

Navigation barTintColor and tintColor is set

How to get an Array with jQuery, multiple <input> with the same name

You can't use same id for multiple elements in a document. Keep the ids different and name same for the elements.

<input type="text" id="task1" name="task" />
<input type="text" id="task2" name="task" />
<input type="text" id="task3" name="task" />
<input type="text" id="task4" name="task" />
<input type="text" id="task5" name="task" />

var newArray = new Array();

$("input:text[name=task]").each(function(){
    newArray.push($(this));
});

HEAD and ORIG_HEAD in Git

My understanding is that HEAD points the current branch, while ORIG_HEAD is used to store the previous HEAD before doing "dangerous" operations.

For example git-rebase and git-am record the original tip of branch before they apply any changes.