Programs & Examples On #Library project

Best way to incorporate Volley (or other library) into Android Studio project

UPDATE:

compile 'com.android.volley:volley:1.0.0'

OLD ANSWER: You need the next in your build.gradle of your app module:

dependencies {
        compile 'com.mcxiaoke.volley:library:1.0.19'
        (Rest of your dependencies)

    }

This is not the official repo but is a highly trusted one.

ActionBarActivity: cannot be resolved to a type

It does not sound like you imported the library right especially when you say at the point Add the library to your application project: I felt lost .. basically because I don't have the "add" option by itself .. however I clicked on "add library" and moved on ..

in eclipse you need to right click on the project, go to Properties, select Android in the list then Add to add the library

follow this tutorial in the docs

http://developer.android.com/tools/support-library/setup.html

Difference between Big-O and Little-O Notation

The big-O notation has a companion called small-o notation. The big-O notation says the one function is asymptotical no more than another. To say that one function is asymptotically less than another, we use small-o notation. The difference between the big-O and small-o notations is analogous to the difference between <= (less than equal) and < (less than).

Make $JAVA_HOME easily changable in Ubuntu

Traditionally, if you only want to change the variable in your terminal windows, set it in .bashrc file, which is sourced each time a new terminal is opened. .profile file is not sourced each time you open a new terminal.

See the difference between .profile and .bashrc in question: What's the difference between .bashrc, .bash_profile, and .environment?

.bashrc should solve your problem. However, it is not the proper solution since you are using Ubuntu. See the relevant Ubuntu help page "Session-wide environment variables". Thus, no wonder that .profile does not work for you. I use Ubuntu 12.04 and xfce. I set up my .profile and it is simply not taking effect even if I log out and in. Similar experience here. So you may have to use .pam_environment file and totally forget about .profile, and .bashrc. And NOTE that .pam_environment is not a script file.

Creating folders inside a GitHub repository without using Git

After searching a lot I find out that it is possible to create a new folder from the web interface, but it would require you to have at least one file within the folder when creating it.

When using the normal way of creating new files through the web interface, you can type in the folder into the file name to create the file within that new directory.

For example, if I would like to create the file filename.md in a series of sub-folders, I can do this (taken from the GitHub blog):

Enter image description here

How to call on a function found on another file?

Your sprite is created mid way through the playerSprite function... it also goes out of scope and ceases to exist at the end of that same function. The sprite must be created where you can pass it to playerSprite to initialize it and also where you can pass it to your draw function.

Perhaps declare it above your first while?

Check if process returns 0 with batch file

How to write a compound statement with if?

You can write a compound statement in an if block using parenthesis. The first parenthesis must come on the line with the if and the second on a line by itself.

if %ERRORLEVEL% == 0 (
    echo ErrorLevel is zero
    echo A second statement
) else if %ERRORLEVEL% == 1 (
    echo ErrorLevel is one
    echo A second statement
) else (
   echo ErrorLevel is > 1
   echo A second statement
)

Postgresql 9.2 pg_dump version mismatch

For me the issue was updating psql apt-get wasn't resolving newer versions, even after update. The following worked.

Ubuntu

Start with the import of the GPG key for PostgreSQL packages.

sudo apt-get install wget ca-certificates
wget --quiet -O - https://www.postgresql.org/media/keys/ACCC4CF8.asc | sudo apt-key add -

Now add the repository to your system.

sudo sh -c 'echo "deb http://apt.postgresql.org/pub/repos/apt/ `lsb_release -cs`-pgdg main" >> /etc/apt/sources.list.d/pgdg.list'

Install PostgreSQL on Ubuntu

sudo apt-get update
sudo apt-get install postgresql postgresql-contrib

https://www.postgresql.org/download/linux/ubuntu/

What is a good Hash Function?

There are two major purposes of hashing functions:

  • to disperse data points uniformly into n bits.
  • to securely identify the input data.

It's impossible to recommend a hash without knowing what you're using it for.

If you're just making a hash table in a program, then you don't need to worry about how reversible or hackable the algorithm is... SHA-1 or AES is completely unnecessary for this, you'd be better off using a variation of FNV. FNV achieves better dispersion (and thus fewer collisions) than a simple prime mod like you mentioned, and it's more adaptable to varying input sizes.

If you're using the hashes to hide and authenticate public information (such as hashing a password, or a document), then you should use one of the major hashing algorithms vetted by public scrutiny. The Hash Function Lounge is a good place to start.

how to check if string contains '+' character

[+]is simpler

    String s = "ddjdjdj+kfkfkf";

    if(s.contains ("+"))
    {
        String parts[] = s.split("[+]");
        s =  parts[0]; // i want to strip part after  +
    }
    System.out.println(s);

Mockito - difference between doReturn() and when()

Continuing this answer, There is another difference that if you want your method to return different values for example when it is first time called, second time called etc then you can pass values so for example...

PowerMockito.doReturn(false, false, true).when(SomeClass.class, "SomeMethod", Matchers.any(SomeClass.class));

So it will return false when the method is called in same test case and then it will return false again and lastly true.

In android how to set navigation drawer header image and name programmatically in class file?

Here is the method you can use to get header view and set data accourdingly

val headerView: View? = navigationView.getHeaderView(0) // Index of the added headerView  

// Now you can access child views of the header view
val titleTextView: TextView? = headerView?.findViewById(R.id.titleTextView)

Get push notification while App in foreground iOS

Here is the code to receive Push Notification when app in active state (foreground or open). UNUserNotificationCenter documentation

@available(iOS 10.0, *)
func userNotificationCenter(center: UNUserNotificationCenter, willPresentNotification notification: UNNotification, withCompletionHandler completionHandler: (UNNotificationPresentationOptions) -> Void)
{
     completionHandler([UNNotificationPresentationOptions.Alert,UNNotificationPresentationOptions.Sound,UNNotificationPresentationOptions.Badge])
}

If you need to access userInfo of notification use code: notification.request.content.userInfo

How to display image from database using php

Displaying an image from MySql Db.

$db = mysqli_connect("localhost","root","","DbName"); 
$sql = "SELECT * FROM products WHERE id = $id";
$sth = $db->query($sql);
$result=mysqli_fetch_array($sth);
echo '<img src="data:image/jpeg;base64,'.base64_encode( $result['image'] ).'"/>';

Permission denied on accessing host directory in Docker

I verified that chcon -Rt svirt_sandbox_file_t /path/to/volume does work and you don't have to run as a privileged container.

This is on:

  • Docker version 0.11.1-dev, build 02d20af/0.11.1
  • CentOS 7 as the host and container with SELinux enabled.

How to set shape's opacity?

Use this one, I've written this to my app,

<?xml version="1.0" encoding="utf-8"?>
<!--  res/drawable/rounded_edittext.xml -->
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle" android:padding="10dp">
    <solid android:color="#882C383E"/>
    <corners
        android:bottomRightRadius="5dp"
        android:bottomLeftRadius="5dp"
        android:topLeftRadius="5dp"
        android:topRightRadius="5dp"/>
</shape>

Jenkins "Console Output" log location in filesystem

@Bruno Lavit has a great answer, but if you want you can just access the log and download it as txt file to your workspace from the job's URL:

${BUILD_URL}/consoleText

Then it's only a matter of downloading this page to your ${Workspace}

  • You can use "Invoke ANT" and use the GET target
  • On Linux you can use wget to download it to your workspace
  • etc.

Good luck!

Edit: The actual log file on the file system is not on the slave, but kept in the Master machine. You can find it under: $JENKINS_HOME/jobs/$JOB_NAME/builds/lastSuccessfulBuild/log

If you're looking for another build just replace lastSuccessfulBuild with the build you're looking for.

Color picker utility (color pipette) in Ubuntu

You can install the package gcolor2 for this:

sudo apt-get install gcolor2

Then:

Applications -> Graphics -> GColor2

Return from lambda forEach() in java

If you want to return a boolean value, then you can use something like this (much faster than filter):

players.stream().anyMatch(player -> player.getName().contains(name));

How do I jump out of a foreach loop in C#?

foreach(string s in sList)
{
    if(s.equals("ok"))
    {
             return true;
    }
}
return false;

how to format date in Component of angular 5

Refer to the below link,

https://angular.io/api/common/DatePipe

**Code Sample**

@Component({
 selector: 'date-pipe',
 template: `<div>
   <p>Today is {{today | date}}</p>
   <p>Or if you prefer, {{today | date:'fullDate'}}</p>
   <p>The time is {{today | date:'h:mm a z'}}</p>
 </div>`
})
// Get the current date and time as a date-time value.
export class DatePipeComponent {
  today: number = Date.now();
}

{{today | date:'MM/dd/yyyy'}} output: 17/09/2019

or

{{today | date:'shortDate'}} output: 17/9/19

How do I change column default value in PostgreSQL?

'SET' is forgotten

ALTER TABLE ONLY users ALTER COLUMN lang SET DEFAULT 'en_GB';

How do I configure IIS for URL Rewriting an AngularJS application in HTML5 mode?

I write out a rule in web.config after $locationProvider.html5Mode(true) is set in app.js.

Hope, helps someone out.

  <system.webServer>
    <rewrite>
      <rules>
        <rule name="AngularJS Routes" stopProcessing="true">
          <match url=".*" />
          <conditions logicalGrouping="MatchAll">
            <add input="{REQUEST_FILENAME}" matchType="IsFile" negate="true" />
            <add input="{REQUEST_FILENAME}" matchType="IsDirectory" negate="true" />
            <add input="{REQUEST_URI}" pattern="^/(api)" negate="true" />
          </conditions>
          <action type="Rewrite" url="/" />
        </rule>
      </rules>
    </rewrite>
  </system.webServer>

In my index.html I added this to <head>

<base href="/">

Don't forget to install IIS URL Rewrite on server.

Also if you use Web API and IIS, this will work if your API is at www.yourdomain.com/api because of the third input (third line of condition).

How do I find the value of $CATALINA_HOME?

Just as a addition. You can find the Catalina Paths in

->RUN->RUN CONFIGURATIONS->APACHE TOMCAT->ARGUMENTS

In the VM Arguments the Paths are listed and changeable

Spark Dataframe distinguish columns with duplicated name

You can use def drop(col: Column) method to drop the duplicated column,for example:

DataFrame:df1

+-------+-----+
| a     | f   |
+-------+-----+
|107831 | ... |
|107831 | ... |
+-------+-----+

DataFrame:df2

+-------+-----+
| a     | f   |
+-------+-----+
|107831 | ... |
|107831 | ... |
+-------+-----+

when I join df1 with df2, the DataFrame will be like below:

val newDf = df1.join(df2,df1("a")===df2("a"))

DataFrame:newDf

+-------+-----+-------+-----+
| a     | f   | a     | f   |
+-------+-----+-------+-----+
|107831 | ... |107831 | ... |
|107831 | ... |107831 | ... |
+-------+-----+-------+-----+

Now, we can use def drop(col: Column) method to drop the duplicated column 'a' or 'f', just like as follows:

val newDfWithoutDuplicate = df1.join(df2,df1("a")===df2("a")).drop(df2("a")).drop(df2("f"))

Get full path of the files in PowerShell

This worked for me, and produces a list of names:

$Thisfile=(get-childitem -path 10* -include '*.JPG' -recurse).fullname

I found it by using get-member -membertype properties, an incredibly useful command. most of the options it gives you are appended with a .<thing>, like fullname is here. You can stick the same command;

  | get-member -membertype properties 

at the end of any command to get more information on the things you can do with them and how to access those:

get-childitem -path 10* -include '*.JPG' -recurse | get-member -membertype properties

E: gnupg, gnupg2 and gnupg1 do not seem to be installed, but one of them is required for this operation

In your Dockerfile, run this first:

apt-get update && apt-get install -y gnupg2

Shuffle an array with python, randomize array item order with python

Just in case you want a new array you can use sample:

import random
new_array = random.sample( array, len(array) )

Explaining Apache ZooKeeper

I understand the ZooKeeper in general but had problems with the terms "quorum" and "split brain" so maybe I can share my findings with you (I consider myself also a layman).

Let's say we have a ZooKeeper cluster of 5 servers. One of the servers will become the leader and the others will become followers.

  • These 5 servers form a quorum. Quorum simply means "these servers can vote upon who should be the leader".

  • So the voting is based on majority. Majority simply means "more than half" so more than half of the number of servers must agree for a specific server to become the leader.

  • So there is this bad thing that may happen called "split brain". A split brain is simply this, as far as I understand: The cluster of 5 servers splits into two parts, or let's call it "server teams", with maybe one part of 2 and the other of 3 servers. This is really a bad situation as if both "server teams" must execute a specific order how would you decide wich team should be preferred? They might have received different information from the clients. So it is really important to know what "server team" is still relevant and which one can/should be ignored.

  • Majority is also the reason you should use an odd number of servers. If you have 4 servers and a split brain where 2 servers seperate then both "server teams" could say "hey, we want to decide who is the leader!" but how should you decide which 2 servers you should choose? With 5 servers it's simple: The server team with 3 servers has the majority and is allowed to select the new leader.

  • Even if you just have 3 servers and one of them fails the other 2 still form the majority and can agree that one of them will become the new leader.

I realize once you think about it some time and understand the terms it's not so complicated anymore. I hope this also helps anyone in understanding these terms.

Apache server keeps crashing, "caught SIGTERM, shutting down"

SIGTERM is used to restart Apache (provided that it's setup in init to auto-restart): http://httpd.apache.org/docs/2.2/stopping.html

The entries you see in the logs are almost certainly there because your provider used SIGTERM for that purpose. If it's truly crashing, not even serving static content, then that sounds like some sort of a thread/connection exhaustion issue. Perhaps a DoS that holds connections open?

Should definitely be something for your provider to investigate.

In a URL, should spaces be encoded using %20 or +?

You can use either - which means most people opt for "+" as it's more human readable.

Altering a column: null to not null

In my case I had difficulties with the posted answers. I ended up using the following:

ALTER TABLE table_name CHANGE COLUMN column_name column_name VARCHAR(200) NOT NULL DEFAULT '';

Change VARCHAR(200) to your datatype, and optionally change the default value.

If you don't have a default value you're going to have a problem making this change, as default would be null creating a conflict.

What is the coolest thing you can do in <10 lines of simple code? Help me inspire beginners!

I taught a class for students with learning disabilities, ages 11-12. We were using Hypercard and they discovered they could record the position of an object (image, box, etc.) as they moved it and play it back (animation). Although this is not coding, they wanted to do more like: delete one of the moves without recording it all over again. I told them they would have to go to the code and change it.

You could see who had a knack for computers/programming when they prefered to do it with code because they had more control.

Doing a complex macro in Excel and then learning what the code is doing could be a gateway to VBA.

Depending on the age group or level of interest, it could be tough to jump straight into code, but it is the end that counts.

Getting Error - ORA-01858: a non-numeric character was found where a numeric was expected

You can solve the problem by checking if your date matches a REGEX pattern. If not, then NULL (or something else you prefer).

In my particular case it was necessary because I have >20 DATE columns saved as CHAR, so I don't know from which column the error is coming from.

Returning to your query:

1. Declare a REGEX pattern.
It is usually a very long string which will certainly pollute your code (you may want to reuse it as well).

define REGEX_DATE = "'your regex pattern goes here'"

Don't forget a single quote inside a double quote around your Regex :-)

A comprehensive thread about Regex date validation you'll find here.

2. Use it as the first CASE condition:

To use Regex validation in the SELECT statement, you cannot use REGEXP_LIKE (it's only valid in WHERE. It took me a long time to understand why my code was not working. So it's certainly worth a note.

Instead, use REGEXP_INSTR
For entries not found in the pattern (your case) use REGEXP_INSTR (variable, pattern) = 0 .

    DEFINE REGEX_DATE = "'your regex pattern goes here'"

    SELECT   c.contract_num,
         CASE
            WHEN REGEXP_INSTR(c.event_dt, &REGEX_DATE) = 0 THEN NULL
            WHEN   (  MAX (TO_CHAR (TO_DATE (c.event_dt, 'YYYY-MM-DD'), 'MMDD'))
                    - MIN (TO_CHAR (TO_DATE (c.event_dt, 'YYYY-MM-DD'), 'MMDD')))
                 / COUNT (c.event_occurrence) < 32
            THEN
              'Monthly'
            WHEN       (  MAX (
                            TO_CHAR (TO_DATE (c.event_dt, 'YYYY-MM-DD'), 'MMDD'))
                        - MIN (
                            TO_CHAR (TO_DATE (c.event_dt, 'YYYY-MM-DD'), 'MMDD')))
                     / COUNT (c.event_occurrence) >= 32
                 AND   (  MAX (
                            TO_CHAR (TO_DATE (c.event_dt, 'YYYY-MM-DD'), 'MMDD'))
                        - MIN (
                            TO_CHAR (TO_DATE (c.event_dt, 'YYYY-MM-DD'), 'MMDD')))
                     / COUNT (c.event_occurrence) < 91
            THEN
              'Quarterley'
            ELSE
              'Yearly'
         END
FROM     ps_ca_bp_events c
GROUP BY c.contract_num;

Updating Python on Mac

On a mac use the following in the terminal to update python if you have anaconda:

conda update python

How to check if an integer is within a range of numbers in PHP?

if (($num >= $lower_boundary) && ($num <= $upper_boundary)) {

You may want to adjust the comparison operators if you want the boundary values not to be valid.

Why am I getting ImportError: No module named pip ' right after installing pip?

I was facing same issue and resolved using following steps

1) Go to your paython package and rename "python37._pth" to python37._pth.save

2) curl https://bootstrap.pypa.io/get-pip.py -o get-pip.py

3) then run python get-pip.py

4) pip install django

Hope this help

Getting mouse position in c#

To get the position look at the OnMouseMove event. The MouseEventArgs will give you the x an y positions...

protected override void OnMouseMove(MouseEventArgs mouseEv) 

To set the mouse position use the Cursor.Position property.

http://msdn.microsoft.com/en-us/library/system.windows.forms.cursor.position.aspx

What is the (best) way to manage permissions for Docker shared volumes?

For secure and change root for docker container an docker host try use --uidmap and --private-uids options

https://github.com/docker/docker/pull/4572#issuecomment-38400893

Also you may remove several capabilities (--cap-drop) in docker container for security

http://opensource.com/business/14/9/security-for-docker

UPDATE support should come in docker > 1.7.0

UPDATE Version 1.10.0 (2016-02-04) add --userns-remap flag https://github.com/docker/docker/blob/master/CHANGELOG.md#security-2

How do you use String.substringWithRange? (or, how do Ranges work in Swift?)

In Swift3

For ex: a variable "Duke James Thomas", we need to get "James".

let name = "Duke James Thomas"
let range: Range<String.Index> = name.range(of:"James")!
let lastrange: Range<String.Index> = img.range(of:"Thomas")!
var middlename = name[range.lowerBound..<lstrange.lowerBound]
print (middlename)

Send file using POST from a Python script

From: https://requests.readthedocs.io/en/latest/user/quickstart/#post-a-multipart-encoded-file

Requests makes it very simple to upload Multipart-encoded files:

with open('report.xls', 'rb') as f:
    r = requests.post('http://httpbin.org/post', files={'report.xls': f})

That's it. I'm not joking - this is one line of code. The file was sent. Let's check:

>>> r.text
{
  "origin": "179.13.100.4",
  "files": {
    "report.xls": "<censored...binary...data>"
  },
  "form": {},
  "url": "http://httpbin.org/post",
  "args": {},
  "headers": {
    "Content-Length": "3196",
    "Accept-Encoding": "identity, deflate, compress, gzip",
    "Accept": "*/*",
    "User-Agent": "python-requests/0.8.0",
    "Host": "httpbin.org:80",
    "Content-Type": "multipart/form-data; boundary=127.0.0.1.502.21746.1321131593.786.1"
  },
  "data": ""
}

How do I log errors and warnings into a file?

Simply put these codes at top of your PHP/index file:

error_reporting(E_ALL); // Error/Exception engine, always use E_ALL

ini_set('ignore_repeated_errors', TRUE); // always use TRUE

ini_set('display_errors', FALSE); // Error/Exception display, use FALSE only in production environment or real server. Use TRUE in development environment

ini_set('log_errors', TRUE); // Error/Exception file logging engine.
ini_set('error_log', 'your/path/to/errors.log'); // Logging file path

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

NOTE: When I first spent time reading about REST, idempotence was a confusing concept to try to get right. I still didn't get it quite right in my original answer, as further comments (and Jason Hoetger's answer) have shown. For a while, I have resisted updating this answer extensively, to avoid effectively plagiarizing Jason, but I'm editing it now because, well, I was asked to (in the comments).

After reading my answer, I suggest you also read Jason Hoetger's excellent answer to this question, and I will try to make my answer better without simply stealing from Jason.

Why is PUT idempotent?

As you noted in your RFC 2616 citation, PUT is considered idempotent. When you PUT a resource, these two assumptions are in play:

  1. You are referring to an entity, not to a collection.

  2. The entity you are supplying is complete (the entire entity).

Let's look at one of your examples.

{ "username": "skwee357", "email": "[email protected]" }

If you POST this document to /users, as you suggest, then you might get back an entity such as

## /users/1

{
    "username": "skwee357",
    "email": "[email protected]"
}

If you want to modify this entity later, you choose between PUT and PATCH. A PUT might look like this:

PUT /users/1
{
    "username": "skwee357",
    "email": "[email protected]"       // new email address
}

You can accomplish the same using PATCH. That might look like this:

PATCH /users/1
{
    "email": "[email protected]"       // new email address
}

You'll notice a difference right away between these two. The PUT included all of the parameters on this user, but PATCH only included the one that was being modified (email).

When using PUT, it is assumed that you are sending the complete entity, and that complete entity replaces any existing entity at that URI. In the above example, the PUT and PATCH accomplish the same goal: they both change this user's email address. But PUT handles it by replacing the entire entity, while PATCH only updates the fields that were supplied, leaving the others alone.

Since PUT requests include the entire entity, if you issue the same request repeatedly, it should always have the same outcome (the data you sent is now the entire data of the entity). Therefore PUT is idempotent.

Using PUT wrong

What happens if you use the above PATCH data in a PUT request?

GET /users/1
{
    "username": "skwee357",
    "email": "[email protected]"
}
PUT /users/1
{
    "email": "[email protected]"       // new email address
}

GET /users/1
{
    "email": "[email protected]"      // new email address... and nothing else!
}

(I'm assuming for the purposes of this question that the server doesn't have any specific required fields, and would allow this to happen... that may not be the case in reality.)

Since we used PUT, but only supplied email, now that's the only thing in this entity. This has resulted in data loss.

This example is here for illustrative purposes -- don't ever actually do this. This PUT request is technically idempotent, but that doesn't mean it isn't a terrible, broken idea.

How can PATCH be idempotent?

In the above example, PATCH was idempotent. You made a change, but if you made the same change again and again, it would always give back the same result: you changed the email address to the new value.

GET /users/1
{
    "username": "skwee357",
    "email": "[email protected]"
}
PATCH /users/1
{
    "email": "[email protected]"       // new email address
}

GET /users/1
{
    "username": "skwee357",
    "email": "[email protected]"       // email address was changed
}
PATCH /users/1
{
    "email": "[email protected]"       // new email address... again
}

GET /users/1
{
    "username": "skwee357",
    "email": "[email protected]"       // nothing changed since last GET
}

My original example, fixed for accuracy

I originally had examples that I thought were showing non-idempotency, but they were misleading / incorrect. I am going to keep the examples, but use them to illustrate a different thing: that multiple PATCH documents against the same entity, modifying different attributes, do not make the PATCHes non-idempotent.

Let's say that at some past time, a user was added. This is the state that you are starting from.

{
  "id": 1,
  "name": "Sam Kwee",
  "email": "[email protected]",
  "address": "123 Mockingbird Lane",
  "city": "New York",
  "state": "NY",
  "zip": "10001"
}

After a PATCH, you have a modified entity:

PATCH /users/1
{"email": "[email protected]"}

{
  "id": 1,
  "name": "Sam Kwee",
  "email": "[email protected]",    // the email changed, yay!
  "address": "123 Mockingbird Lane",
  "city": "New York",
  "state": "NY",
  "zip": "10001"
}

If you then repeatedly apply your PATCH, you will continue to get the same result: the email was changed to the new value. A goes in, A comes out, therefore this is idempotent.

An hour later, after you have gone to make some coffee and take a break, someone else comes along with their own PATCH. It seems the Post Office has been making some changes.

PATCH /users/1
{"zip": "12345"}

{
  "id": 1,
  "name": "Sam Kwee",
  "email": "[email protected]",  // still the new email you set
  "address": "123 Mockingbird Lane",
  "city": "New York",
  "state": "NY",
  "zip": "12345"                      // and this change as well
}

Since this PATCH from the post office doesn't concern itself with email, only zip code, if it is repeatedly applied, it will also get the same result: the zip code is set to the new value. A goes in, A comes out, therefore this is also idempotent.

The next day, you decide to send your PATCH again.

PATCH /users/1
{"email": "[email protected]"}

{
  "id": 1,
  "name": "Sam Kwee",
  "email": "[email protected]",
  "address": "123 Mockingbird Lane",
  "city": "New York",
  "state": "NY",
  "zip": "12345"
}

Your patch has the same effect it had yesterday: it set the email address. A went in, A came out, therefore this is idempotent as well.

What I got wrong in my original answer

I want to draw an important distinction (something I got wrong in my original answer). Many servers will respond to your REST requests by sending back the new entity state, with your modifications (if any). So, when you get this response back, it is different from the one you got back yesterday, because the zip code is not the one you received last time. However, your request was not concerned with the zip code, only with the email. So your PATCH document is still idempotent - the email you sent in PATCH is now the email address on the entity.

So when is PATCH not idempotent, then?

For a full treatment of this question, I again refer you to Jason Hoetger's answer. I'm just going to leave it at that, because I honestly don't think I can answer this part better than he already has.

Returning a value even if no result

You can use COALESCE

SELECT COALESCE(SUM(column),0)
FROM   table

What is the standard naming convention for html/css ids and classes?

tl;dr;

There is no one true answer. You can pick one of the many out there, or create your own standards based on what makes sense, depending upon who you're working with. And it is 100% dependent upon the platform.


Original Post

Just one more alternative standard to consider:

<div id="id_name" class="class-name"></div>

And in your script:

var variableName = $("#id_name .class-name");

This just uses a camelCase, under_score, and hyphen-ation respectively for variables, ids, and classes. I've read about this standard on a couple of different websites. Although a little redundant in css/jquery selectors, redundancies make it easier to catch errors. eg: If you see .unknown_name or #unknownName in your CSS file, you know you need to figure out what that's actually referring to.


UPDATE 2019

(Hyphens are called 'kebab-case', underscores are called 'snake_case', and then you have 'TitleCase', 'pascalCase')

I personally dislike hyphens. I originally posted this as one alternative (because the rules are simple). However, Hyphens make selection shortcuts very difficult (double click, ctrl/option + left/right, and ctrl/cmd+D in vsCode. Also, class names and file names are the only place where hyphens work, because they're almost always in quotes or in css, etc. But the shortcut thing still applies.

In addition to variables, class names, and ids, you also want to look at file name conventions. And Git Branches.

My office's coding group actually had a meeting a month or two ago to discuss how we were going to name things. For git branches, we couldn't decide between 321-the_issue_description or 321_the-issue-description. (I wanted 321_theIssueDescription, but my coworkers didn't like that.)

An Example, to demonstrate working with other peoples' standards...

Vue.js does have a standard. Actually they have two alternate standards for several of their items. I dislike both of their versions for filenames. They recommend either "/path/kebab-case.vue" or "/path/TitleCase.Vue". The former is harder to rename, unless you're specifically trying to rename part of it. The latter is not good for cross-platform compatibility. I would prefer "/path/snake_case.vue". However, when working with other people or existing projects, it's important to follow whatever standard was already laid out. Therefore I go with kebab-case for filenames in Vue, even though I'll totally complain about it. Because not following that means changing a lot of files that vue-cli sets up.

How to subtract X days from a date using Java calendar?

int x = -1;
Calendar cal = ...;
cal.add(Calendar.DATE, x);

See java.util.Calendar#add(int,int)

ImportError: No module named 'django.core.urlresolvers'

You need replace all occurrences of:

from django.core.urlresolvers import reverse

to:

from django.urls import reverse

enter image description here

NOTE: The same apply to reverse_lazy

in Pycharm Cmd+Shift+R for starting replacment in Path.

Getting the last element of a split string array

var str = "hello,how,are,you,today?";
var pieces = str.split(/[\s,]+/);

At this point, pieces is an array and pieces.length contains the size of the array so to get the last element of the array, you check pieces[pieces.length-1]. If there are no commas or spaces it will simply output the string as it was given.

alert(pieces[pieces.length-1]); // alerts "today?"

How to get your Netbeans project into Eclipse

There's a very easy way if you were using a web application just follow this link.

just do in eclipse :

File > import > web > war file

Then select the war file of your app :)) very easy !!

Split code over multiple lines in an R script

This will keep the \n character, but you can also just wrap the quote in parentheses. Especially useful in RMarkdown.

t <- ("
this is a long
string
")

Angularjs loading screen on ajax request

The best way to do this is to use response interceptors along with custom directive. And the process can further be improved using pub/sub mechanism using $rootScope.$broadcast & $rootScope.$on methods.

As the whole process is documented in a well written blog article, I'm not going to repeat that here again. Please refer to that article to come up with your needed implementation.

How to source virtualenv activate in a Bash script

Although it doesn't add the "(.env)" prefix to the shell prompt, I found this script works as expected.

#!/bin/bash
script_dir=`dirname $0`
cd $script_dir
/bin/bash -c ". ../.env/bin/activate; exec /bin/bash -i"

e.g.

user@localhost:~/src$ which pip
/usr/local/bin/pip
user@localhost:~/src$ which python
/usr/bin/python
user@localhost:~/src$ ./shell
user@localhost:~/src$ which pip
~/.env/bin/pip
user@localhost:~/src$ which python
~/.env/bin/python
user@localhost:~/src$ exit
exit

Default values and initialization in Java

These are the main factors involved:

  1. member variable (default OK)
  2. static variable (default OK)
  3. final member variable (not initialized, must set on constructor)
  4. final static variable (not initialized, must set on a static block {})
  5. local variable (not initialized)

Note 1: you must initialize final member variables on every implemented constructor!

Note 2: you must initialize final member variables inside the block of the constructor itself, not calling another method that initializes them. For instance, this is not valid:

private final int memberVar;

public Foo() {
    // Invalid initialization of a final member
    init();
}

private void init() {
    memberVar = 10;
}

Note 3: arrays are Objects in Java, even if they store primitives.

Note 4: when you initialize an array, all of its items are set to default, independently of being a member or a local array.

I am attaching a code example, presenting the aforementioned cases:

public class Foo {
    // Static and member variables are initialized to default values

    // Primitives
    private int a; // Default 0
    private static int b; // Default 0

    // Objects
    private Object c; // Default NULL
    private static Object d; // Default NULL

    // Arrays (note: they are objects too, even if they store primitives)
    private int[] e; // Default NULL
    private static int[] f; // Default NULL

    // What if declared as final?

    // Primitives
    private final int g; // Not initialized. MUST set in the constructor
    private final static int h; // Not initialized. MUST set in a static {}

    // Objects
    private final Object i; // Not initialized. MUST set in constructor
    private final static Object j; // Not initialized. MUST set in a static {}

    // Arrays
    private final int[] k; // Not initialized. MUST set in constructor
    private final static int[] l; // Not initialized. MUST set in a static {}

    // Initialize final statics
    static {
        h = 5;
        j = new Object();
        l = new int[5]; // Elements of l are initialized to 0
    }

    // Initialize final member variables
    public Foo() {
        g = 10;
        i = new Object();
        k = new int[10]; // Elements of k are initialized to 0
    }

    // A second example constructor
    // You have to initialize final member variables to every constructor!
    public Foo(boolean aBoolean) {
        g = 15;
        i = new Object();
        k = new int[15]; // Elements of k are initialized to 0
    }

    public static void main(String[] args) {
        // Local variables are not initialized
        int m; // Not initialized
        Object n; // Not initialized
        int[] o; // Not initialized

        // We must initialize them before use
        m = 20;
        n = new Object();
        o = new int[20]; // Elements of o are initialized to 0
    }
}

textarea character limit

This is entirely untested but it should do what you need.

Update : here's a jsfiddle to look at. Seems to be working. link

You would past it into a js file and reference it after your jquery reference. You would then call it like this..

$("textarea").characterCounter(200);

A brief explanation of what is going on..

On every keyup event the function is checking what type of key is pressed. If it is acceptable the the counter will check the count, trim any excess and prevent any further input once the limit is reached.

The plugin should handle pasting into the target too.

  ; (function ($) {
        $.fn.characterCounter = function (limit) {
            return this.filter("textarea, input:text").each(function () {
                var $this = $(this),
                  checkCharacters = function (event) {

                      if ($this.val().length > limit) {

                          // Trim the string as paste would allow you to make it 
                          // more than the limit.
                          $this.val($this.val().substring(0, limit))
                          // Cancel the original event
                          event.preventDefault();
                          event.stopPropagation();

                      }
                  };

                $this.keyup(function (event) {

                    // Keys "enumeration"
                    var keys = {
                        BACKSPACE: 8,
                        TAB: 9,
                        LEFT: 37,
                        UP: 38,
                        RIGHT: 39,
                        DOWN: 40
                    };

                    // which normalizes keycode and charcode.
                    switch (event.which) {

                        case keys.UP:
                        case keys.DOWN:
                        case keys.LEFT:
                        case keys.RIGHT:
                        case keys.TAB:
                            break;
                        default:
                            checkCharacters(event);
                            break;
                    }   

                });

                // Handle cut/paste.
                $this.bind("paste cut", function (event) {
                    // Delay so that paste value is captured.
                    setTimeout(function () { checkCharacters(event); event = null; }, 150);
                });
            });
        };
    } (jQuery));

Save string to the NSUserDefaults?

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

// saving an NSString
[prefs setObject:@"TextToSave" forKey:@"keyToLookupString"];

// saving an NSInteger
[prefs setInteger:42 forKey:@"integerKey"];

// saving a Double
[prefs setDouble:3.1415 forKey:@"doubleKey"];

// saving a Float
[prefs setFloat:1.2345678 forKey:@"floatKey"];

// This is suggested to synch prefs, but is not needed (I didn't put it in my tut)
[prefs synchronize];

Retrieving

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

// getting an NSString
NSString *myString = [prefs stringForKey:@"keyToLookupString"];

// getting an NSInteger
NSInteger myInt = [prefs integerForKey:@"integerKey"];

// getting an Float
float myFloat = [prefs floatForKey:@"floatKey"];

Python argparse command line flags without arguments

As you have it, the argument w is expecting a value after -w on the command line. If you are just looking to flip a switch by setting a variable True or False, have a look here (specifically store_true and store_false)

import argparse

parser = argparse.ArgumentParser()
parser.add_argument('-w', action='store_true')

where action='store_true' implies default=False.

Conversely, you could haveaction='store_false', which implies default=True.

What are functional interfaces used for in Java 8?

Not at all. Lambda expressions are the one and only point of that annotation.

Cannot retrieve string(s) from preferences (settings)

All your exercise conditionals are separate and the else is only tied to the last if statement. Use else if to bind them all together in the way I believe you intend.

How do I use reflection to call a generic method?

Calling a generic method with a type parameter known only at runtime can be greatly simplified by using a dynamic type instead of the reflection API.

To use this technique the type must be known from the actual object (not just an instance of the Type class). Otherwise, you have to create an object of that type or use the standard reflection API solution. You can create an object by using the Activator.CreateInstance method.

If you want to call a generic method, that in "normal" usage would have had its type inferred, then it simply comes to casting the object of unknown type to dynamic. Here's an example:

class Alpha { }
class Beta { }
class Service
{
    public void Process<T>(T item)
    {
        Console.WriteLine("item.GetType(): " + item.GetType()
                          + "\ttypeof(T): " + typeof(T));
    }
}

class Program
{
    static void Main(string[] args)
    {
        var a = new Alpha();
        var b = new Beta();

        var service = new Service();
        service.Process(a); // Same as "service.Process<Alpha>(a)"
        service.Process(b); // Same as "service.Process<Beta>(b)"

        var objects = new object[] { a, b };
        foreach (var o in objects)
        {
            service.Process(o); // Same as "service.Process<object>(o)"
        }
        foreach (var o in objects)
        {
            dynamic dynObj = o;
            service.Process(dynObj); // Or write "service.Process((dynamic)o)"
        }
    }
}

And here's the output of this program:

item.GetType(): Alpha    typeof(T): Alpha
item.GetType(): Beta     typeof(T): Beta
item.GetType(): Alpha    typeof(T): System.Object
item.GetType(): Beta     typeof(T): System.Object
item.GetType(): Alpha    typeof(T): Alpha
item.GetType(): Beta     typeof(T): Beta

Process is a generic instance method that writes the real type of the passed argument (by using the GetType() method) and the type of the generic parameter (by using typeof operator).

By casting the object argument to dynamic type we deferred providing the type parameter until runtime. When the Process method is called with the dynamic argument then the compiler doesn't care about the type of this argument. The compiler generates code that at runtime checks the real types of passed arguments (by using reflection) and choose the best method to call. Here there is only this one generic method, so it's invoked with a proper type parameter.

In this example, the output is the same as if you wrote:

foreach (var o in objects)
{
    MethodInfo method = typeof(Service).GetMethod("Process");
    MethodInfo generic = method.MakeGenericMethod(o.GetType());
    generic.Invoke(service, new object[] { o });
}

The version with a dynamic type is definitely shorter and easier to write. You also shouldn't worry about performance of calling this function multiple times. The next call with arguments of the same type should be faster thanks to the caching mechanism in DLR. Of course, you can write code that cache invoked delegates, but by using the dynamic type you get this behaviour for free.

If the generic method you want to call don't have an argument of a parametrized type (so its type parameter can't be inferred) then you can wrap the invocation of the generic method in a helper method like in the following example:

class Program
{
    static void Main(string[] args)
    {
        object obj = new Alpha();

        Helper((dynamic)obj);
    }

    public static void Helper<T>(T obj)
    {
        GenericMethod<T>();
    }

    public static void GenericMethod<T>()
    {
        Console.WriteLine("GenericMethod<" + typeof(T) + ">");
    }
}

Increased type safety

What is really great about using dynamic object as a replacement for using reflection API is that you only lose compile time checking of this particular type that you don't know until runtime. Other arguments and the name of the method are staticly analysed by the compiler as usual. If you remove or add more arguments, change their types or rename method name then you'll get a compile-time error. This won't happen if you provide the method name as a string in Type.GetMethod and arguments as the objects array in MethodInfo.Invoke.

Below is a simple example that illustrates how some errors can be caught at compile time (commented code) and other at runtime. It also shows how the DLR tries to resolve which method to call.

interface IItem { }
class FooItem : IItem { }
class BarItem : IItem { }
class Alpha { }

class Program
{
    static void Main(string[] args)
    {
        var objects = new object[] { new FooItem(), new BarItem(), new Alpha() };
        for (int i = 0; i < objects.Length; i++)
        {
            ProcessItem((dynamic)objects[i], "test" + i, i);

            //ProcesItm((dynamic)objects[i], "test" + i, i);
            //compiler error: The name 'ProcesItm' does not
            //exist in the current context

            //ProcessItem((dynamic)objects[i], "test" + i);
            //error: No overload for method 'ProcessItem' takes 2 arguments
        }
    }

    static string ProcessItem<T>(T item, string text, int number)
        where T : IItem
    {
        Console.WriteLine("Generic ProcessItem<{0}>, text {1}, number:{2}",
                          typeof(T), text, number);
        return "OK";
    }
    static void ProcessItem(BarItem item, string text, int number)
    {
        Console.WriteLine("ProcessItem with Bar, " + text + ", " + number);
    }
}

Here we again execute some method by casting the argument to the dynamic type. Only verification of first argument's type is postponed to runtime. You will get a compiler error if the name of the method you're calling doesn't exist or if other arguments are invalid (wrong number of arguments or wrong types).

When you pass the dynamic argument to a method then this call is lately bound. Method overload resolution happens at runtime and tries to choose the best overload. So if you invoke the ProcessItem method with an object of BarItem type then you'll actually call the non-generic method, because it is a better match for this type. However, you'll get a runtime error when you pass an argument of the Alpha type because there's no method that can handle this object (a generic method has the constraint where T : IItem and Alpha class doesn't implement this interface). But that's the whole point. The compiler doesn't have information that this call is valid. You as a programmer know this, and you should make sure that this code runs without errors.

Return type gotcha

When you're calling a non-void method with a parameter of dynamic type, its return type will probably be dynamic too. So if you'd change previous example to this code:

var result = ProcessItem((dynamic)testObjects[i], "test" + i, i);

then the type of the result object would be dynamic. This is because the compiler don't always know which method will be called. If you know the return type of the function call then you should implicitly convert it to the required type so the rest of the code is statically typed:

string result = ProcessItem((dynamic)testObjects[i], "test" + i, i);

You'll get a runtime error if the type doesn't match.

Actually, if you try to get the result value in the previous example then you'll get a runtime error in the second loop iteration. This is because you tried to save the return value of a void function.

What is meaning of negative dbm in signal strength?

At ms end Rx lev ranges 0 to -120 dbm Mean antenna power which received at ms end alway less than 1mW.

Thats why it always -ve.

SQL to LINQ Tool

I know that this isn't what you asked for but LINQPad is a really great tool to teach yourself LINQ (and it's free :o).

When time isn't critical, I have been using it for the last week or so instead or a query window in SQL Server and my LINQ skills are getting better and better.

It's also a nice little code snippet tool. Its only downside is that the free version doesn't have IntelliSense.

What does DIM stand for in Visual Basic and BASIC?

The Dim keyword is optional, when we are using it with modifiers- Public, Protected, Friend, Protected Friend,Private,Shared,Shadows,Static,ReadOnly etc. e.g. - Static nTotal As Integer

For reference type, we have to use new keyword to create the new instance of the class or structure. e.g. Dim lblTop As New System.Windows.Forms.Label.

Dim statement can be used with out a datatype when you set Option Infer to On. In that case the compiler infers the data type of a variable from the type of its initialization expression. Example :

Option Infer On

Module SampleMod

Sub Main()

 Dim nExpVar = 5

The above statement is equivalent to- Dim nExpVar As Integer

Scrolling a flexbox with overflowing content

The solution for this problem is just to add overflow: auto; to the .content for making the content wrapper scrollable.

Furthermore, there are circumstances occurring along with Flexbox wrapper and overflowed scrollable content like this codepen.

The solution is to add overflow: hidden (or auto); to the parent of the wrapper (set with overflow: auto;) around large contents.

Simple java program of pyramid

public static void printPyramid(int number) {
    int size = 5;
    for (int k = 1; k <= size; k++) {
        for (int i = (size+2); i > k; i--) {
            System.out.print(" ");
        }
        for (int j = 1; j <= k; j++) {
            System.out.print(" *");
        }
        System.out.println();
    }
}

How to outline text in HTML / CSS

With HTML5's support for svg, you don't need to rely on shadow hacks.

_x000D_
_x000D_
<svg  width="100%" viewBox="0 0 600 100">_x000D_
<text x=0 y=20 font-size=12pt fill=white stroke=black stroke-width=0.75>_x000D_
    This text exposes its vector representation, _x000D_
    making it easy to style shape-wise without hacks. _x000D_
    HTML5 supports it, so no browser issues. Only downside _x000D_
    is that svg has its own quirks and learning curve _x000D_
    (c.f. bounding box issue/no typesetting by default)_x000D_
</text>_x000D_
</svg>
_x000D_
_x000D_
_x000D_

In Python script, how do I set PYTHONPATH?

PYTHONPATH ends up in sys.path, which you can modify at runtime.

import sys
sys.path += ["whatever"]

Triangle Draw Method

there is no command directly to draw Triangle. For Drawing of triangle we have to use the concept of lines here.

i.e, g.drawLines(Coordinates of points)

Is there a way to remove the separator line from a UITableView?

In Swift:

tableView.separatorStyle = .None

How to undo "git commit --amend" done instead of "git commit"

use the ref-log:

git branch fixing-things HEAD@{1}
git reset fixing-things

you should then have all your previously amended changes only in your working copy and can commit again

to see a full list of previous indices type git reflog

How to clear input buffer in C?

You can do it (also) this way:

fseek(stdin,0,SEEK_END);

Find and replace strings in vim on multiple lines

We don't need to bother entering the current line number.

If you would like to change each foo to bar for current line (.) and the two next lines (+2), simply do:

:.,+2s/foo/bar/g

If you want to confirm before changes are made, replace g with gc:

:.,+2s/foo/bar/gc

inverting image in Python with OpenCV

You can use "tilde" operator to do it:

import cv2
image = cv2.imread("img.png")
image = ~image
cv2.imwrite("img_inv.png",image)

This is because the "tilde" operator (also known as unary operator) works doing a complement dependent on the type of object

for example for integers, its formula is:

x + (~x) = -1

but in this case, opencv use an "uint8 numpy array object" for its images so its range is from 0 to 255

so if we apply this operator to an "uint8 numpy array object" like this:

import numpy as np
x1 = np.array([25,255,10], np.uint8) #for example
x2 = ~x1
print (x2)

we will have as a result:

[230 0 245]

because its formula is:

x2 = 255 - x1

and that is exactly what we want to do to solve the problem.

Spring MVC: Error 400 The request sent by the client was syntactically incorrect

Please keep your

<form method="POST" action="XYZ">

@RequestMapping(value="/XYZ", method=RequestMethod.POST)
    public void handleSave(@RequestParam String action){

Your form action attribute value must match to value of @RequestMapping, So that Spring MVC can resolve it.

Also, as you told it is giving 404 after changing, for this, can you please check whether control is entering inside handleSave() method.

I think, as you are not returning any thing from handleSave() method, you have to look at it.

if it still not work, can you please post your spring logs.

Also, make sure that your request should come like

/PORTAL/save

if there is anything between like PORTAL/jsp/save the mention in @RequestMapping(value="/jsp/save")

Converting string to byte array in C#

This what worked for me

byte[] bytes = Convert.FromBase64String(textString);

And in reverse:

string str = Convert.ToBase64String(bytes);

.htaccess rewrite to redirect root URL to subdirectory

This seemed the simplest solution:

RewriteEngine on
RewriteCond %{REQUEST_URI} ^/$
RewriteRule (.*) http://www.example.com/store [R=301,L]

I was getting redirect loops with some of the other solutions.

Correct MIME Type for favicon.ico?

When you're serving an .ico file to be used as a favicon, it doesn't matter. All major browsers recognize both mime types correctly. So you could put:

<!-- IE -->
<link rel="shortcut icon" type="image/x-icon" href="favicon.ico" />
<!-- other browsers -->
<link rel="icon" type="image/x-icon" href="favicon.ico" />

or the same with image/vnd.microsoft.icon, and it will work with all browsers.

Note: There is no IANA specification for the MIME-type image/x-icon, so it does appear that it is a little more unofficial than image/vnd.microsoft.icon.

The only case in which there is a difference is if you were trying to use an .ico file in an <img> tag (which is pretty unusual). Based on previous testing, some browsers would only display .ico files as images when they were served with the MIME-type image/x-icon. More recent tests show: Chromium, Firefox and Edge are fine with both content types, IE11 is not. If you can, just avoid using ico files as images, use png.

How to save the contents of a div as a image?

Do something like this:

A <div> with ID of #imageDIV, another one with ID #download and a hidden <div> with ID #previewImage.

Include the latest version of jquery, and jspdf.debug.js from the jspdf CDN

Then add this script:

var element = $("#imageDIV"); // global variable
var getCanvas; // global variable
$('document').ready(function(){
  html2canvas(element, {
    onrendered: function (canvas) {
      $("#previewImage").append(canvas);
      getCanvas = canvas;
    }
  });
});
$("#download").on('click', function () {
  var imgageData = getCanvas.toDataURL("image/png");
  // Now browser starts downloading it instead of just showing it
  var newData = imageData.replace(/^data:image\/png/, "data:application/octet-stream");
  $("#download").attr("download", "image.png").attr("href", newData);
});

The div will be saved as a PNG on clicking the #download

Open Facebook Page in Facebook App (if installed) on Android

Okay I modifed @AndroidMechanics Code, because on devices were facebook is disabled the app crashes!

here is the modifed getFacebookUrl:

public String getFacebookPageURL(Context context) {
        PackageManager packageManager = context.getPackageManager();
        try {
            int versionCode = packageManager.getPackageInfo("com.facebook.katana", 0).versionCode;

            boolean activated =  packageManager.getApplicationInfo("com.facebook.katana", 0).enabled;
            if(activated){
                if ((versionCode >= 3002850)) { 
                    return "fb://facewebmodal/f?href=" + FACEBOOK_URL;
                } else { 
                    return "fb://page/" + FACEBOOK_PAGE_ID;
                }
            }else{
                return FACEBOOK_URL;
            }
         } catch (PackageManager.NameNotFoundException e) {
            return FACEBOOK_URL; 
        }
    }

The only added thing is to look if the app is disabled or not if it is disabled the app will call the webbrowser!

Delete rows containing specific strings in R

You can use this function if it's multiple string df[!grepl("REVERSE|GENJJS", df$Name),]

How to do date/time comparison

Recent protocols prefer usage of RFC3339 per golang time package documentation.

In general RFC1123Z should be used instead of RFC1123 for servers that insist on that format, and RFC3339 should be preferred for new protocols. RFC822, RFC822Z, RFC1123, and RFC1123Z are useful for formatting; when used with time.Parse they do not accept all the time formats permitted by the RFCs.

cutOffTime, _ := time.Parse(time.RFC3339, "2017-08-30T13:35:00Z")
// POSTDATE is a date time field in DB (datastore)
query := datastore.NewQuery("db").Filter("POSTDATE >=", cutOffTime).

"elseif" syntax in JavaScript

Conditional statements are used to perform different actions based on different conditions.

Use if to specify a block of code to be executed, if a specified condition is true

Use else to specify a block of code to be executed, if the same condition is false

Use else if to specify a new condition to test, if the first condition is false

Room persistance library. Delete all

I had issues with delete all method when using RxJava to execute this task on background. This is how I finally solved it:

@Dao
interface UserDao {
    @Query("DELETE FROM User")
    fun deleteAll()
}

and

fun deleteAllUsers() {
    return Maybe.fromAction(userDao::deleteAll)
        .subscribeOn(Schedulers.io())
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe ({
            d("database rows cleared: $it")
        }, {
            e(it)
        }).addTo(compositeDisposable)
}

In Angular, how to pass JSON object/array into directive?

As you say, you don't need to request the file twice. Pass it from your controller to your directive. Assuming you use the directive inside the scope of the controller:

.controller('MyController', ['$scope', '$http', function($scope, $http) {
  $http.get('locations/locations.json').success(function(data) {
      $scope.locations = data;
  });
}

Then in your HTML (where you call upon the directive).
Note: locations is a reference to your controllers $scope.locations.

<div my-directive location-data="locations"></div>

And finally in your directive

...
scope: {
  locationData: '=locationData'
},
controller: ['$scope', function($scope){
  // And here you can access your data
  $scope.locationData
}]
...

This is just an outline to point you in the right direction, so it's incomplete and not tested.

I keep getting "Uncaught SyntaxError: Unexpected token o"

Another hints for Unexpected token errors. There are two major differences between javascript objects and json:

  1. json data must be always quoted with double quotes.
  2. keys must be quoted

Correct JSON

 {
    "english": "bag",
    "kana": "kaban",
    "kanji": "K"
}

Error JSON 1

 {
    'english': 'bag',
    'kana': 'kaban',
    'kanji': 'K'
 }

Error JSON 2

 {
    english: "bag",
    kana: "kaban",
    kanji: "K"
}

Remark

This is not a direct answer for that question. But it's an answer for Unexpected token errors. So it may be help others who stumple upon that question.

How many threads is too many?

As Pax rightly said, measure, don't guess. That what I did for DNSwitness and the results were suprising: the ideal number of threads was much higher than I thought, something like 15,000 threads to get the fastest results.

Of course, it depends on many things, that's why you must measure yourself.

Complete measures (in French only) in Combien de fils d'exécution ?.

Convert ASCII number to ASCII Character in C

You can assign int to char directly.

int a = 65;
char c = a;
printf("%c", c);

In fact this will also work.

printf("%c", a);  // assuming a is in valid range

javax.servlet.ServletException cannot be resolved to a type in spring web app

import javax.servlet

STEP 1

Go to properties of your project ( with Alt+Enter or righ-click )

STEP 2

check on Apache Tomcat v7.0 under Targeted Runtime and it works.

source: https://stackoverflow.com/a/9287149

Split string to equal length substrings in Java

@Test
public void regexSplit() {
    String source = "Thequickbrownfoxjumps";
    // define matcher, any char, min length 1, max length 4
    Matcher matcher = Pattern.compile(".{1,4}").matcher(source);
    List<String> result = new ArrayList<>();
    while (matcher.find()) {
        result.add(source.substring(matcher.start(), matcher.end()));
    }
    String[] expected = {"Theq", "uick", "brow", "nfox", "jump", "s"};
    assertArrayEquals(result.toArray(), expected);
}

Cannot download Docker images behind a proxy

On Ubuntu 14.04 (Trusty Tahr) with Docker 1.9.1, I just uncommented the http_proxy line, updated the value and then restarted the Docker service.

export http_proxy="http://proxy.server.com:80"

and then

service docker restart

How to parseInt in Angular.js

Inside template this working finely.

<!DOCTYPE html>
<html>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.9/angular.min.js"></script>
<body>

<div ng-app="">
<input ng-model="name" value="0">
<p>My first expression: {{ (name-0) + 5 }}</p>
</div>

</body>
</html>

How to use Greek symbols in ggplot2?

Use expression(delta) where 'delta' for lowercase d and 'Delta' to get capital ?.

Here's full list of Greek characters:

? a alpha
? ß beta
G ? gamma
? d delta
? e epsilon
? ? zeta
? ? eta
T ? theta
? ? iota
? ? kappa
? ? lambda
? µ mu
? ? nu
? ? xi
? ? omicron
? p pi
? ? rho
S s sigma
? t tau
? ? upsilon
F f phi
? ? chi
? ? psi
O ? omega

EDIT: Copied from comments, when using in conjunction with other words use like: expression(Delta*"price")

identifier "string" undefined?

Perhaps you wanted to #include<string>, not <string.h>. std::string also needs a namespace qualification, or an explicit using directive.

convert streamed buffers to utf8-string

Single Buffer

If you have a single Buffer you can use its toString method that will convert all or part of the binary contents to a string using a specific encoding. It defaults to utf8 if you don't provide a parameter, but I've explicitly set the encoding in this example.

var req = http.request(reqOptions, function(res) {
    ...

    res.on('data', function(chunk) {
        var textChunk = chunk.toString('utf8');
        // process utf8 text chunk
    });
});

Streamed Buffers

If you have streamed buffers like in the question above where the first byte of a multi-byte UTF8-character may be contained in the first Buffer (chunk) and the second byte in the second Buffer then you should use a StringDecoder. :

var StringDecoder = require('string_decoder').StringDecoder;

var req = http.request(reqOptions, function(res) {
    ...
    var decoder = new StringDecoder('utf8');

    res.on('data', function(chunk) {
        var textChunk = decoder.write(chunk);
        // process utf8 text chunk
    });
});

This way bytes of incomplete characters are buffered by the StringDecoder until all required bytes were written to the decoder.

Parse strings to double with comma and point

You want to treat dot (.) like comma (,). So, replace

if (double.TryParse(values[i, j], out tmp))

with

if (double.TryParse(values[i, j].Replace('.', ','), out tmp))

How to list the properties of a JavaScript object?

Building on the accepted answer.

If the Object has properties you want to call say .properties() try!

var keys = Object.keys(myJSONObject);

for (var j=0; j < keys.length; j++) {
  Object[keys[j]].properties();
}

Breaking up long strings on multiple lines in Ruby without stripping newlines

I modified Zack's answer since I wanted spaces and interpolation but not newlines and used:

%W[
  It's a nice day "#{name}"
  for a walk!
].join(' ')

where name = 'fred' this produces It's a nice day "fred" for a walk!

How to read and write to a text file in C++?

Default c++ mechanism for file IO is called streams. Streams can be of three flavors: input, output and inputoutput. Input streams act like sources of data. To read data from an input stream you use >> operator:

istream >> my_variable; //This code will read a value from stream into your variable.

Operator >> acts different for different types. If in the example above my_variable was an int, then a number will be read from the strem, if my_variable was a string, then a word would be read, etc. You can read more then one value from the stream by writing istream >> a >> b >> c; where a, b and c would be your variables.

Output streams act like sink to which you can write your data. To write your data to a stream, use << operator.

ostream << my_variable; //This code will write a value from your variable into stream.

As with input streams, you can write several values to the stream by writing something like this:

ostream << a << b << c;

Obviously inputoutput streams can act as both.

In your code sample you use cout and cin stream objects. cout stands for console-output and cin for console-input. Those are predefined streams for interacting with default console.

To interact with files, you need to use ifstream and ofstream types. Similar to cin and cout, ifstream stands for input-file-stream and ofstream stands for output-file-stream.

Your code might look like this:

#include <iostream>
#include <fstream>

using namespace std;

int start()
{
    cout << "Welcome...";

    // do fancy stuff

    return 0;
}

int main ()
{
    string usreq, usr, yn, usrenter;

    cout << "Is this your first time using TEST" << endl;
    cin >> yn;
    if (yn == "y")
    {
        ifstream iusrfile;
        ofstream ousrfile;
        iusrfile.open("usrfile.txt");
        iusrfile >> usr;
        cout << iusrfile; // I'm not sure what are you trying to do here, perhaps print iusrfile contents?
        iusrfile.close();
        cout << "Please type your Username. \n";
        cin >> usrenter;
        if (usrenter == usr)
        {
            start ();
        }
    }
    else
    {
        cout << "THAT IS NOT A REGISTERED USERNAME.";
    }

    return 0;
}

For further reading you might want to look at c++ I/O reference

How do I remove carriage returns with Ruby?

lines2 = lines.split.join("\n")

How do I request and process JSON with python?

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

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

duplicate 'row.names' are not allowed error

It seems the problem can arise from more than one reasons. Following two steps worked when I was having same error.

  1. I saved my file as MS-DOS csv. ( Earlier it was saved in as just csv , excel starter 2010 ). Opened the csv in notepad++. No coma was inconsistent (consistency as described above @Brian).
  2. Noticed I was not using argument sep="," . I used and it worked ( even though that is default argument!)

Concatenating date with a string in Excel

This is the numerical representation of the date. The thing you get when referring to dates from formulas like that.

You'll have to do:

= A1 & TEXT(A2, "mm/dd/yyyy")

The biggest problem here is that the format specifier is locale-dependent. It will not work/produce not what expected if the file is opened with a differently localized Excel.

Now, you could have a user-defined function:

public function AsDisplayed(byval c as range) as string
  AsDisplayed = c.Text
end function

and then

= A1 & AsDisplayed(A2)

But then there's a bug (feature?) in Excel because of which the .Text property is suddenly not available during certain stages of the computation cycle, and your formulas display #VALUE instead of what they should.

That is, it's bad either way.

How to printf "unsigned long" in C?

For int %d

For long int %ld

For long long int %lld

For unsigned long long int %llu

JPA or JDBC, how are they different?

JDBC is a much lower-level (and older) specification than JPA. In it's bare essentials, JDBC is an API for interacting with a database using pure SQL - sending queries and retrieving results. It has no notion of objects or hierarchies. When using JDBC, it's up to you to translate a result set (essentially a row/column matrix of values from one or more database tables, returned by your SQL query) into Java objects.

Now, to understand and use JDBC it's essential that you have some understanding and working knowledge of SQL. With that also comes a required insight into what a relational database is, how you work with it and concepts such as tables, columns, keys and relationships. Unless you have at least a basic understanding of databases, SQL and data modelling you will not be able to make much use of JDBC since it's really only a thin abstraction on top of these things.

HRESULT: 0x800A03EC on Worksheet.range

I got this exception because I typed:

ws.get_Range("K:K").EntireColumn.AutoFit();
ws.get_Range("N:N").EntireColumn.AutoFit();
ws.get_Range("0:0").EntireColumn.AutoFit();

See a mistake? Hint: Excel is accepting indexing from 1, but not from 0 as C# does.

How to mark a method as obsolete or deprecated?

Add an annotation to the method using the keyword Obsolete. Message argument is optional but a good idea to communicate why the item is now obsolete and/or what to use instead.
Example:

[System.Obsolete("use myMethodB instead")]
void myMethodA()

Calculate the mean by group

Adding alternative base R approach, which remains fast under various cases.

rowsummean <- function(df) {
  rowsum(df$speed, df$dive) / tabulate(df$dive)
}

Borrowing the benchmarks from @Ari:

10 rows, 2 groups

res1

10 million rows, 10 groups

res2

10 million rows, 1000 groups

res3

How do you POST to a page using the PHP header() function?

The answer to this is very needed today because not everyone wants to use cURL to consume web services. Also PHP does allow for this using the following code

function get_info()
{
    $post_data = array(
        'test' => 'foobar',
        'okay' => 'yes',
        'number' => 2
    );

    // Send a request to example.com
    $result = $this->post_request('http://www.example.com/', $post_data);

    if ($result['status'] == 'ok'){

        // Print headers
        echo $result['header'];

        echo '<hr />';

        // print the result of the whole request:
        echo $result['content'];

    }
    else {
        echo 'A error occured: ' . $result['error'];
    }

}

function post_request($url, $data, $referer='') {

    // Convert the data array into URL Parameters like a=b&foo=bar etc.
    $data = http_build_query($data);

    // parse the given URL
    $url = parse_url($url);

    if ($url['scheme'] != 'http') {
        die('Error: Only HTTP request are supported !');
    }

    // extract host and path:
    $host = $url['host'];
    $path = $url['path'];

    // open a socket connection on port 80 - timeout: 30 sec
    $fp = fsockopen($host, 80, $errno, $errstr, 30);

    if ($fp){

        // send the request headers:
        fputs($fp, "POST $path HTTP/1.1\r\n");
        fputs($fp, "Host: $host\r\n");

        if ($referer != '')
            fputs($fp, "Referer: $referer\r\n");

        fputs($fp, "Content-type: application/x-www-form-urlencoded\r\n");
        fputs($fp, "Content-length: ". strlen($data) ."\r\n");
        fputs($fp, "Connection: close\r\n\r\n");
        fputs($fp, $data);

        $result = '';
        while(!feof($fp)) {
            // receive the results of the request
            $result .= fgets($fp, 128);
        }
    }
    else {
        return array(
            'status' => 'err',
            'error' => "$errstr ($errno)"
        );
    }

    // close the socket connection:
    fclose($fp);

    // split the result header from the content
    $result = explode("\r\n\r\n", $result, 2);

    $header = isset($result[0]) ? $result[0] : '';
    $content = isset($result[1]) ? $result[1] : '';

    // return as structured array:
    return array(
        'status' => 'ok',
        'header' => $header,
        'content' => $content);

}

Ignore <br> with CSS?

You can simply convert it in a comment..

Or you can do this:

br {
display: none;
}

But if you do not want it why are you puting that there?

Annotation-specified bean name conflicts with existing, non-compatible bean def

I had the same issue. I solved it by using the following steps(Editor: IntelliJ):

  1. View -> Tool Windows -> Maven Project. Opens your projects in a sub-window.
  2. Click on the arrow next to your project.
  3. Click on the lifecycle.
  4. Click on clean.

Set Label Text with JQuery

You can try:

<label id ="label_id"></label>
 $("#label_id").html('value');

How can I get a user's media from Instagram without authenticating as a user?

If you bypass Oauth you probably wouldn't know which instagram user they are. That being said there are a few ways to get instagram images without authentication.

  1. Instagram's API allows you to view a user's most popular images without authenticating. Using the following endpoint: Here is link

  2. Instagram provides rss feeds for tags at this.

  3. Instagram user pages are public, so you can use PHP with CURL to get their page and a DOM parser to search the html for the image tags you want.

SVN Error - Not a working copy

You must have deleted a SVN - base file from your project (which are read-only files). Due to this you get this error.

Check out a fresh project again, merge the changes (if any) of your older SVN project with new one using "Winmerge" and commit the changes in your latest check out.

Newline in string attribute

I realize this is on older question but just wanted to add that

Environment.NewLine

also works if doing this through code.

Cut Corners using CSS

If the parent element has a solid color background, you can use pseudo-elements to create the effect:

_x000D_
_x000D_
div {_x000D_
    height: 300px;_x000D_
    background: red;_x000D_
    position: relative;_x000D_
}_x000D_
_x000D_
div:before {_x000D_
    content: '';_x000D_
    position: absolute;_x000D_
    top: 0; right: 0;_x000D_
    border-top: 80px solid white;_x000D_
    border-left: 80px solid red;_x000D_
    width: 0;_x000D_
}
_x000D_
<div></div>
_x000D_
_x000D_
_x000D_

http://jsfiddle.net/2bZAW/


P.S. The upcoming border-corner-shape is exactly what you're looking for. Too bad it might get cut out of the spec, and never make it into any browsers in the wild :(

How to use XPath contains() here?

I already gave my +1 to Jeff Yates' solution.

Here is a quick explanation why your approach does not work. This:

//ul[@class='featureList' and contains(li, 'Model')]

encounters a limitation of the contains() function (or any other string function in XPath, for that matter).

The first argument is supposed to be a string. If you feed it a node list (giving it "li" does that), a conversion to string must take place. But this conversion is done for the first node in the list only.

In your case the first node in the list is <li><b>Type:</b> Clip Fan</li> (converted to a string: "Type: Clip Fan") which means that this:

//ul[@class='featureList' and contains(li, 'Type')]

would actually select a node!

Nginx: Permission denied for nginx on Ubuntu

I just patch nginx binary replacing path /var/log/nginx/error.log and other with local path.

$ perl -pi \
    -e 's@/var/log/nginx/@_var_log_nginx/@g;' \
    -e 's@/var/lib/nginx/@_var_lib_nginx/@g;' \
    -e 's@/var/run/nginx.pid@_var_run/nginx.pid@g;' \
    -e 's@/run/nginx.pid@_run/nginx.pid@g;' \
    < /usr/sbin/nginx > nginx
$ chmod +x nginx
$ mkdir _var_log_nginx _var_lib_nginx _var_run _run
$ ./nginx -p . -c nginx.conf

It works for testing.

How to convert OutputStream to InputStream?

You will need an intermediate class which will buffer between. Each time InputStream.read(byte[]...) is called, the buffering class will fill the passed in byte array with the next chunk passed in from OutputStream.write(byte[]...). Since the sizes of the chunks may not be the same, the adapter class will need to store a certain amount until it has enough to fill the read buffer and/or be able to store up any buffer overflow.

This article has a nice breakdown of a few different approaches to this problem:

http://blog.ostermiller.org/convert-java-outputstream-inputstream

Selecting last element in JavaScript array

var last = function( obj, key ) { 
    var a = obj[key];
    return a[a.length - 1];
};

last(loc, 'f096012e-2497-485d-8adb-7ec0b9352c52');

How can I make my custom objects Parcelable?

You can find some examples of this here, here (code is taken here), and here.

You can create a POJO class for this, but you need to add some extra code to make it Parcelable. Have a look at the implementation.

public class Student implements Parcelable{
        private String id;
        private String name;
        private String grade;

        // Constructor
        public Student(String id, String name, String grade){
            this.id = id;
            this.name = name;
            this.grade = grade;
       }
       // Getter and setter methods
       .........
       .........

       // Parcelling part
       public Student(Parcel in){
           String[] data = new String[3];

           in.readStringArray(data);
           // the order needs to be the same as in writeToParcel() method
           this.id = data[0];
           this.name = data[1];
           this.grade = data[2];
       }

       @?verride
       public int describeContents(){
           return 0;
       }

       @Override
       public void writeToParcel(Parcel dest, int flags) {
           dest.writeStringArray(new String[] {this.id,
                                               this.name,
                                               this.grade});
       }
       public static final Parcelable.Creator CREATOR = new Parcelable.Creator() {
           public Student createFromParcel(Parcel in) {
               return new Student(in); 
           }

           public Student[] newArray(int size) {
               return new Student[size];
           }
       };
   }

Once you have created this class, you can easily pass objects of this class through the Intent like this, and recover this object in the target activity.

intent.putExtra("student", new Student("1","Mike","6"));

Here, the student is the key which you would require to unparcel the data from the bundle.

Bundle data = getIntent().getExtras();
Student student = (Student) data.getParcelable("student");

This example shows only String types. But, you can parcel any kind of data you want. Try it out.

EDIT: Another example, suggested by Rukmal Dias.

how to create 100% vertical line in css

Use an absolutely positioned pseudo element:

ul:after {
  content: '';
  width: 0;
  height: 100%;
  position: absolute;
  border: 1px solid black;
  top: 0;
  left: 100px;
}

Demo

"Eliminate render-blocking CSS in above-the-fold content"

Few tips that may help:

  • I came across this article in CSS optimization yesterday: CSS profiling for ... optimization
    A lot of useful info on CSS and what CSS causes the most performance drains.

  • I saw the following presentation on jQueryUK on "hidden secrets" in Googe Chrome (Canary) Dev Tools: DevTools Can do that. Check out the sections on Time to First Paint, repaints and costly CSS.

  • Also, if you are using a loader like requireJS you could have a look at one of the CSS loader plugins, called require-CSS, which uses CSSO - a optimzer that also does structural optimization, eg. merging blocks with identical properties. I used it a few times and it can save quite a lot of CSS from case to case.

Off the question: I second @Enzino in creating a sprite for all the small icons you are loading. The file sizes are so small it does not really warrant a server roundtrip for each icon. Also keep in mind the total number of concurrent http requests are browser can do. So requests for a larger number of small icons are "render-blocking" as well. Although an empty page compare to yours, I like how duckduckgo loads for example.

Java, How to add library files in netbeans?

Quick solution in NetBeans 6.8.

In the Projects window right-click on the name of the project that lacks library -> Properties -> The Project Properties window opens. In Categories tree select "Libraries" node -> On the right side of the Project Properties window press button "Add JAR/Folder" -> Select jars you need.

You also can see my short Video How-To.

Getting only response header from HTTP POST using curl

While the other answers have not worked for me in all situations, the best solution I could find (working with POST as well), taken from here:

curl -vs 'https://some-site.com' 1> /dev/null

delete_all vs destroy_all?

To avoid the fact that destroy_all instantiates all the records and destroys them one at a time, you can use it directly from the model class.

So instead of :

u = User.find_by_name('JohnBoy')
u.usage_indexes.destroy_all

You can do :

u = User.find_by_name('JohnBoy')
UsageIndex.destroy_all "user_id = #{u.id}"

The result is one query to destroy all the associated records

How to merge two PDF files into one in Java?

If you want to combine two files where one overlays the other (example: document A is a template and document B has the text you want to put on the template), this works:

after creating "doc", you want to write your template (templateFile) on top of that -

   PDDocument watermarkDoc = PDDocument.load(getServletContext()
                .getRealPath(templateFile));
   Overlay overlay = new Overlay();

   overlay.overlay(watermarkDoc, doc);

Custom style to jquery ui dialogs

You can specify a custom class to the top element of the dialog via the option dialogClass

$("#success").dialog({
    ...
    dialogClass:"myClass",
    ...
});

Then you can target this class in CSS via .myClass.ui-dialog.

Rename multiple files in a directory in Python

What about this :

import re
p = re.compile(r'_')
p.split(filename, 1) #where filename is CHEESE_CHEESE_TYPE.***

The imported project "C:\Microsoft.CSharp.targets" was not found

This is a global solution, not dependent on particular package or bin.

In my case, I removed Packages folder from my root directory.

Maybe it happens because of your packages are there but compiler is not finding it's reference. so remove older packages first and add new packages.

Steps to Add new packages

  • First remove, packages folder (it will be near by or one step up to your current project folder).
  • Then restart the project or solution.
  • Now, Rebuild solution file.
  • Project will get new references from nuGet package manager. And your issue will be resolved.

This is not proper solution, but I posted it here because I face same issue.

In my case, I wasn't even able to open my solution in visual studio and didn't get any help with other SO answers.

Easily measure elapsed time

#include <ctime>
#include <cstdio>
#include <iostream>
#include <chrono>
#include <sys/time.h>
using namespace std;
using namespace std::chrono;

void f1()
{
  high_resolution_clock::time_point t1 = high_resolution_clock::now();
  high_resolution_clock::time_point t2 = high_resolution_clock::now();
  double dif = duration_cast<nanoseconds>( t2 - t1 ).count();
  printf ("Elasped time is %lf nanoseconds.\n", dif );
}

void f2()
{
  timespec ts1,ts2;
  clock_gettime(CLOCK_REALTIME, &ts1);
  clock_gettime(CLOCK_REALTIME, &ts2);
  double dif = double( ts2.tv_nsec - ts1.tv_nsec );
  printf ("Elasped time is %lf nanoseconds.\n", dif );
}

void f3()
{
  struct timeval t1,t0;
  gettimeofday(&t0, 0);
  gettimeofday(&t1, 0);
  double dif = double( (t1.tv_usec-t0.tv_usec)*1000);
  printf ("Elasped time is %lf nanoseconds.\n", dif );
}
void f4()
{
  high_resolution_clock::time_point t1 , t2;
  double diff = 0;
  t1 = high_resolution_clock::now() ;
  for(int i = 1; i <= 10 ; i++)
  {
    t2 = high_resolution_clock::now() ;
    diff+= duration_cast<nanoseconds>( t2 - t1 ).count();
    t1 = t2;
  }
  printf ("high_resolution_clock:: Elasped time is %lf nanoseconds.\n", diff/10 );
}

void f5()
{
  timespec ts1,ts2;
  double diff = 0;
  clock_gettime(CLOCK_REALTIME, &ts1);
  for(int i = 1; i <= 10 ; i++)
  {
    clock_gettime(CLOCK_REALTIME, &ts2);
    diff+= double( ts2.tv_nsec - ts1.tv_nsec );
    ts1 = ts2;
  }
  printf ("clock_gettime:: Elasped time is %lf nanoseconds.\n", diff/10 );
}

void f6()
{
  struct timeval t1,t2;
  double diff = 0;
  gettimeofday(&t1, 0);
  for(int i = 1; i <= 10 ; i++)
  {
    gettimeofday(&t2, 0);
    diff+= double( (t2.tv_usec-t1.tv_usec)*1000);
    t1 = t2;
  }
  printf ("gettimeofday:: Elasped time is %lf nanoseconds.\n", diff/10 );
}

int main()
{
  //  f1();
  //  f2();
  //  f3();
  f6();
  f4();
  f5();
  return 0;
}

How do I open phone settings when a button is clicked?

As above @niravdesai said App-prefs. I found that App-Prefs: works for both iOS 9, 10 and 11. devices tested. where as prefs: only works on iOS 9.

Can I create view with parameter in MySQL?

CREATE VIEW MyView AS
   SELECT Column, Value FROM Table;


SELECT Column FROM MyView WHERE Value = 1;

Is the proper solution in MySQL, some other SQLs let you define Views more exactly.

Note: Unless the View is very complicated, MySQL will optimize this just fine.

Differences Between vbLf, vbCrLf & vbCr Constants

The three constants have similar functions nowadays, but different historical origins, and very occasionally you may be required to use one or the other.

You need to think back to the days of old manual typewriters to get the origins of this. There are two distinct actions needed to start a new line of text:

  1. move the typing head back to the left. In practice in a typewriter this is done by moving the roll which carries the paper (the "carriage") all the way back to the right -- the typing head is fixed. This is a carriage return.
  2. move the paper up by the width of one line. This is a line feed.

In computers, these two actions are represented by two different characters - carriage return is CR, ASCII character 13, vbCr; line feed is LF, ASCII character 10, vbLf. In the old days of teletypes and line printers, the printer needed to be sent these two characters -- traditionally in the sequence CRLF -- to start a new line, and so the CRLF combination -- vbCrLf -- became a traditional line ending sequence, in some computing environments.

The problem was, of course, that it made just as much sense to only use one character to mark the line ending, and have the terminal or printer perform both the carriage return and line feed actions automatically. And so before you knew it, we had 3 different valid line endings: LF alone (used in Unix and Macintoshes), CR alone (apparently used in older Mac OSes) and the CRLF combination (used in DOS, and hence in Windows). This in turn led to the complications of DOS / Windows programs having the option of opening files in text mode, where any CRLF pair read from the file was converted to a single CR (and vice versa when writing).

So - to cut a (much too) long story short - there are historical reasons for the existence of the three separate line separators, which are now often irrelevant: and perhaps the best course of action in .NET is to use Environment.NewLine which means someone else has decided for you which to use, and future portability issues should be reduced.

Sending SOAP request using Python Requests

It is indeed possible.

Here is an example calling the Weather SOAP Service using plain requests lib:

import requests
url="http://wsf.cdyne.com/WeatherWS/Weather.asmx?WSDL"
#headers = {'content-type': 'application/soap+xml'}
headers = {'content-type': 'text/xml'}
body = """<?xml version="1.0" encoding="UTF-8"?>
         <SOAP-ENV:Envelope xmlns:ns0="http://ws.cdyne.com/WeatherWS/" xmlns:ns1="http://schemas.xmlsoap.org/soap/envelope/" 
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
            <SOAP-ENV:Header/>
              <ns1:Body><ns0:GetWeatherInformation/></ns1:Body>
         </SOAP-ENV:Envelope>"""

response = requests.post(url,data=body,headers=headers)
print response.content

Some notes:

  • The headers are important. Most SOAP requests will not work without the correct headers. application/soap+xml is probably the more correct header to use (but the weatherservice prefers text/xml
  • This will return the response as a string of xml - you would then need to parse that xml.
  • For simplicity I have included the request as plain text. But best practise would be to store this as a template, then you can load it using jinja2 (for example) - and also pass in variables.

For example:

from jinja2 import Environment, PackageLoader
env = Environment(loader=PackageLoader('myapp', 'templates'))
template = env.get_template('soaprequests/WeatherSericeRequest.xml')
body = template.render()

Some people have mentioned the suds library. Suds is probably the more correct way to be interacting with SOAP, but I often find that it panics a little when you have WDSLs that are badly formed (which, TBH, is more likely than not when you're dealing with an institution that still uses SOAP ;) ).

You can do the above with suds like so:

from suds.client import Client
url="http://wsf.cdyne.com/WeatherWS/Weather.asmx?WSDL"
client = Client(url)
print client ## shows the details of this service

result = client.service.GetWeatherInformation() 
print result 

Note: when using suds, you will almost always end up needing to use the doctor!

Finally, a little bonus for debugging SOAP; TCPdump is your friend. On Mac, you can run TCPdump like so:

sudo tcpdump -As 0 

This can be helpful for inspecting the requests that actually go over the wire.

The above two code snippets are also available as gists:

Python Git Module experiences?

PTBNL's Answer is quite perfect for me. I make a little more for Windows user.

import time
import subprocess
def gitAdd(fileName, repoDir):
    cmd = 'git add ' + fileName
    pipe = subprocess.Popen(cmd, shell=True, cwd=repoDir,stdout = subprocess.PIPE,stderr = subprocess.PIPE )
    (out, error) = pipe.communicate()
    print out,error
    pipe.wait()
    return 

def gitCommit(commitMessage, repoDir):
    cmd = 'git commit -am "%s"'%commitMessage
    pipe = subprocess.Popen(cmd, shell=True, cwd=repoDir,stdout = subprocess.PIPE,stderr = subprocess.PIPE )
    (out, error) = pipe.communicate()
    print out,error
    pipe.wait()
    return 
def gitPush(repoDir):
    cmd = 'git push '
    pipe = subprocess.Popen(cmd, shell=True, cwd=repoDir,stdout = subprocess.PIPE,stderr = subprocess.PIPE )
    (out, error) = pipe.communicate()
    pipe.wait()
    return 

temp=time.localtime(time.time())
uploaddate= str(temp[0])+'_'+str(temp[1])+'_'+str(temp[2])+'_'+str(temp[3])+'_'+str(temp[4])

repoDir='d:\\c_Billy\\vfat\\Programming\\Projector\\billyccm' # your git repository , windows your need to use double backslash for right directory.
gitAdd('.',repoDir )
gitCommit(uploaddate, repoDir)
gitPush(repoDir)

Automatically running a batch file as an administrator

Use

runas /savecred /profile /user:Administrator whateveryouwanttorun.cmd

It will ask for the password the first time only. It will not ask for password again, unless the password is changed, etc.

How to pass complex object to ASP.NET WebApi GET from jQuery ajax call?

If you append json data to query string, and parse it later in web api side. you can parse complex object. It's useful rather than post json object style. This is my solution.

//javascript file 
var data = { UserID: "10", UserName: "Long", AppInstanceID: "100", ProcessGUID: "BF1CC2EB-D9BD-45FD-BF87-939DD8FF9071" };
var request = JSON.stringify(data);
request = encodeURIComponent(request);

doAjaxGet("/ProductWebApi/api/Workflow/StartProcess?data=", request, function (result) {
    window.console.log(result);
});

//webapi file:
[HttpGet]
public ResponseResult StartProcess()
{
    dynamic queryJson = ParseHttpGetJson(Request.RequestUri.Query);
        int appInstanceID = int.Parse(queryJson.AppInstanceID.Value);
    Guid processGUID = Guid.Parse(queryJson.ProcessGUID.Value);
    int userID = int.Parse(queryJson.UserID.Value);
    string userName = queryJson.UserName.Value;
}

//utility function:
public static dynamic ParseHttpGetJson(string query)
{
    if (!string.IsNullOrEmpty(query))
    {
        try
        {
            var json = query.Substring(7, query.Length - 7); //seperate ?data= characters
            json = System.Web.HttpUtility.UrlDecode(json);
            dynamic queryJson = JsonConvert.DeserializeObject<dynamic>(json);

            return queryJson;
        }
        catch (System.Exception e)
        {
            throw new ApplicationException("can't deserialize object as wrong string content!", e);
        }
    }
    else
    {
        return null;
    }
}

How to do joins in LINQ on multiple fields in single join

As a full method chain that would look like this:

lista.SelectMany(a => listb.Where(xi => b.Id == a.Id && b.Total != a.Total),
                (a, b) => new ResultItem
                {
                    Id = a.Id,
                    ATotal = a.Total,
                    BTotal = b.Total
                }).ToList();

What is the difference between exit and return?

  • return returns from the current function; it's a language keyword like for or break.
  • exit() terminates the whole program, wherever you call it from. (After flushing stdio buffers and so on).

The only case when both do (nearly) the same thing is in the main() function, as a return from main performs an exit().

In most C implementations, main is a real function called by some startup code that does something like int ret = main(argc, argv); exit(ret);. The C standard guarantees that something equivalent to this happens if main returns, however the implementation handles it.

Example with return:

#include <stdio.h>

void f(){
    printf("Executing f\n");
    return;
}

int main(){
    f();
    printf("Back from f\n");
}

If you execute this program it prints:

Executing f
Back from f

Another example for exit():

#include <stdio.h>
#include <stdlib.h>

void f(){
    printf("Executing f\n");
    exit(0);
}

int main(){
    f();
    printf("Back from f\n");
}

If you execute this program it prints:

Executing f

You never get "Back from f". Also notice the #include <stdlib.h> necessary to call the library function exit().

Also notice that the parameter of exit() is an integer (it's the return status of the process that the launcher process can get; the conventional usage is 0 for success or any other value for an error).

The parameter of the return statement is whatever the return type of the function is. If the function returns void, you can omit the return at the end of the function.

Last point, exit() come in two flavors _exit() and exit(). The difference between the forms is that exit() (and return from main) calls functions registered using atexit() or on_exit() before really terminating the process while _exit() (from #include <unistd.h>, or its synonymous _Exit from #include <stdlib.h>) terminates the process immediately.

Now there are also issues that are specific to C++.

C++ performs much more work than C when it is exiting from functions (return-ing). Specifically it calls destructors of local objects going out of scope. In most cases programmers won't care much of the state of a program after the processus stopped, hence it wouldn't make much difference: allocated memory will be freed, file ressource closed and so on. But it may matter if your destructor performs IOs. For instance automatic C++ OStream locally created won't be flushed on a call to exit and you may lose some unflushed data (on the other hand static OStream will be flushed).

This won't happen if you are using the good old C FILE* streams. These will be flushed on exit(). Actually, the rule is the same that for registered exit functions, FILE* will be flushed on all normal terminations, which includes exit(), but not calls to _exit() or abort().

You should also keep in mind that C++ provide a third way to get out of a function: throwing an exception. This way of going out of a function will call destructor. If it is not catched anywhere in the chain of callers, the exception can go up to the main() function and terminate the process.

Destructors of static C++ objects (globals) will be called if you call either return from main() or exit() anywhere in your program. They wont be called if the program is terminated using _exit() or abort(). abort() is mostly useful in debug mode with the purpose to immediately stop the program and get a stack trace (for post mortem analysis). It is usually hidden behind the assert() macro only active in debug mode.

When is exit() useful ?

exit() means you want to immediately stops the current process. It can be of some use for error management when we encounter some kind of irrecoverable issue that won't allow for your code to do anything useful anymore. It is often handy when the control flow is complicated and error codes has to be propagated all way up. But be aware that this is bad coding practice. Silently ending the process is in most case the worse behavior and actual error management should be preferred (or in C++ using exceptions).

Direct calls to exit() are especially bad if done in libraries as it will doom the library user and it should be a library user's choice to implement some kind of error recovery or not. If you want an example of why calling exit() from a library is bad, it leads for instance people to ask this question.

There is an undisputed legitimate use of exit() as the way to end a child process started by fork() on Operating Systems supporting it. Going back to the code before fork() is usually a bad idea. This is the rationale explaining why functions of the exec() family will never return to the caller.

In NetBeans how do I change the Default JDK?

If I remember correctly, you'll need to set the netbeans_jdkhome property in your netbeans config file. Should be in your etc/netbeans.conf file.

Convert all first letter to upper case, rest lower for each word

I don't know if the solution below is more or less efficient than jspcal's answer, but I'm pretty sure it requires less object creation than Jamie's and George's.

string s = "THIS IS MY TEXT RIGHT NOW";
StringBuilder sb = new StringBuilder(s.Length);
bool capitalize = true;
foreach (char c in s) {
    sb.Append(capitalize ? Char.ToUpper(c) : Char.ToLower(c));
    capitalize = !Char.IsLetter(c);
}
return sb.ToString();

Reliable way to convert a file to a byte[]

Not to repeat what everyone already have said but keep the following cheat sheet handly for File manipulations:

  1. System.IO.File.ReadAllBytes(filename);
  2. File.Exists(filename)
  3. Path.Combine(folderName, resOfThePath);
  4. Path.GetFullPath(path); // converts a relative path to absolute one
  5. Path.GetExtension(path);

Regular expression negative lookahead

A negative lookahead says, at this position, the following regex can not match.

Let's take a simplified example:

a(?!b(?!c))

a      Match: (?!b) succeeds
ac     Match: (?!b) succeeds
ab     No match: (?!b(?!c)) fails
abe    No match: (?!b(?!c)) fails
abc    Match: (?!b(?!c)) succeeds

The last example is a double negation: it allows a b followed by c. The nested negative lookahead becomes a positive lookahead: the c should be present.

In each example, only the a is matched. The lookahead is only a condition, and does not add to the matched text.

How To Run PHP From Windows Command Line in WAMPServer

That is because you are in 'Interactive Mode' where php evaluates everything you type. To see the end result, you do 'ctrl+z' and Enter. You should see the evaluated result now :)

p.s. run the cmd as Administrator!

Convert date to datetime in Python

You can use the date.timetuple() method and unpack operator *.

args = d.timetuple()[:6]
datetime.datetime(*args)

Convert .pem to .crt and .key

0. Prerequisite: openssl should be installed. On Windows, if Git Bash is installed, try that! Alternate binaries can be found here.

1. Extract .key from .pem:

openssl pkey -in cert.pem -out cert.key

2. Extract .crt from .pem:

openssl crl2pkcs7 -nocrl -certfile cert.pem | openssl pkcs7 -print_certs -out cert.crt

Show a child form in the centre of Parent form in C#

The parent probably isn't yet set when you are trying to access it.

Try this:

loginForm = new SubLogin();
loginForm.Show(this);
loginForm.CenterToParent()

Spring Boot: Is it possible to use external application.properties files in arbitrary directories with a fat jar?

You would be able to launch your spring boot appication with the external properties file path as follows:

java -jar {jar-file-name}.jar 
--spring.config.location=file:///C:/{file-path}/{file-name}.properties

Call Activity method from adapter

Yes you can.

In the adapter Add a new Field :

private Context mContext;

In the adapter Constructor add the following code :

public AdapterName(......, Context context) {
  //your code.
  this.mContext = context;
}

In the getView(...) of Adapter:

Button btn = (Button) convertView.findViewById(yourButtonId);
btn.setOnClickListener(new Button.OnClickListener() {
  @Override
  public void onClick(View v) {
    if (mContext instanceof YourActivityName) {
      ((YourActivityName)mContext).yourDesiredMethod();
    }
  }
});

replace with your own class names where you see your code, your activity etc.

If you need to use this same adapter for more than one activity then :

Create an Interface

public interface IMethodCaller {
    void yourDesiredMethod();
}

Implement this interface in activities you require to have this method calling functionality.

Then in Adapter getView(), call like:

Button btn = (Button) convertView.findViewById(yourButtonId);
btn.setOnClickListener(new Button.OnClickListener() {
    @Override
    public void onClick(View v) {
        if (mContext instanceof IMethodCaller) {
            ((IMethodCaller) mContext).yourDesiredMethod();
        }
    }
});

You are done. If you need to use this adapter for activities which does not require this calling mechanism, the code will not execute (If check fails).

Disable single warning error

as @rampion mentioned, if you are in clang gcc, the warnings are by name, not number, and you'll need to do:

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunused-variable"
// ..your code..
#pragma clang diagnostic pop

this info comes from here

How to convert a String to long in javascript?

JavaScript has a Number type which is a 64 bit floating point number*.

If you're looking to convert a string to a number, use

  1. either parseInt or parseFloat. If using parseInt, I'd recommend always passing the radix too.
  2. use the Unary + operator e.g. +"123456"
  3. use the Number constructor e.g. var n = Number("12343")

*there are situations where the number will internally be held as an integer.

PowerShell script to check the status of a URL

Below is the PowerShell code that I use for basic web URL testing. It includes the ability to accept invalid certs and get detailed information about the results of checking the certificate.

$CertificateValidatorClass = @'
using System;
using System.Collections.Concurrent;
using System.Net;
using System.Security.Cryptography;
using System.Text;

namespace CertificateValidation
{
    public class CertificateValidationResult
    {
        public string Subject { get; internal set; }
        public string Thumbprint { get; internal set; }
        public DateTime Expiration { get; internal set; }
        public DateTime ValidationTime { get; internal set; }
        public bool IsValid { get; internal set; }
        public bool Accepted { get; internal set; }
        public string Message { get; internal set; }

        public CertificateValidationResult()
        {
            ValidationTime = DateTime.UtcNow;
        }
    }

    public static class CertificateValidator
    {
        private static ConcurrentStack<CertificateValidationResult> certificateValidationResults = new ConcurrentStack<CertificateValidationResult>();

        public static CertificateValidationResult[] CertificateValidationResults
        {
            get
            {
                return certificateValidationResults.ToArray();
            }
        }

        public static CertificateValidationResult LastCertificateValidationResult
        {
            get
            {
                CertificateValidationResult lastCertificateValidationResult = null;
                certificateValidationResults.TryPeek(out lastCertificateValidationResult);

                return lastCertificateValidationResult;
            }
        }

        public static bool ServicePointManager_ServerCertificateValidationCallback(object sender, System.Security.Cryptography.X509Certificates.X509Certificate certificate, System.Security.Cryptography.X509Certificates.X509Chain chain, System.Net.Security.SslPolicyErrors sslPolicyErrors)
        {
            StringBuilder certificateValidationMessage = new StringBuilder();
            bool allowCertificate = true;

            if (sslPolicyErrors != System.Net.Security.SslPolicyErrors.None)
            {
                if ((sslPolicyErrors & System.Net.Security.SslPolicyErrors.RemoteCertificateNameMismatch) == System.Net.Security.SslPolicyErrors.RemoteCertificateNameMismatch)
                {
                    certificateValidationMessage.AppendFormat("The remote certificate name does not match.\r\n", certificate.Subject);
                }

                if ((sslPolicyErrors & System.Net.Security.SslPolicyErrors.RemoteCertificateChainErrors) == System.Net.Security.SslPolicyErrors.RemoteCertificateChainErrors)
                {
                    certificateValidationMessage.AppendLine("The certificate chain has the following errors:");
                    foreach (System.Security.Cryptography.X509Certificates.X509ChainStatus chainStatus in chain.ChainStatus)
                    {
                        certificateValidationMessage.AppendFormat("\t{0}", chainStatus.StatusInformation);

                        if (chainStatus.Status == System.Security.Cryptography.X509Certificates.X509ChainStatusFlags.Revoked)
                        {
                            allowCertificate = false;
                        }
                    }
                }

                if ((sslPolicyErrors & System.Net.Security.SslPolicyErrors.RemoteCertificateNotAvailable) == System.Net.Security.SslPolicyErrors.RemoteCertificateNotAvailable)
                {
                    certificateValidationMessage.AppendLine("The remote certificate was not available.");
                    allowCertificate = false;
                }

                System.Console.WriteLine();
            }
            else
            {
                certificateValidationMessage.AppendLine("The remote certificate is valid.");
            }

            CertificateValidationResult certificateValidationResult = new CertificateValidationResult
                {
                    Subject = certificate.Subject,
                    Thumbprint = certificate.GetCertHashString(),
                    Expiration = DateTime.Parse(certificate.GetExpirationDateString()),
                    IsValid = (sslPolicyErrors == System.Net.Security.SslPolicyErrors.None),
                    Accepted = allowCertificate,
                    Message = certificateValidationMessage.ToString()
                };

            certificateValidationResults.Push(certificateValidationResult);
            return allowCertificate;
        }

        public static void SetDebugCertificateValidation()
        {
            ServicePointManager.ServerCertificateValidationCallback = ServicePointManager_ServerCertificateValidationCallback;
        }

        public static void SetDefaultCertificateValidation()
        {
            ServicePointManager.ServerCertificateValidationCallback = null;
        }

        public static void ClearCertificateValidationResults()
        {
            certificateValidationResults.Clear();
        }
    }
}
'@

function Set-CertificateValidationMode
{
    <#
    .SYNOPSIS
    Sets the certificate validation mode.
    .DESCRIPTION
    Set the certificate validation mode to one of three modes with the following behaviors:
        Default -- Performs the .NET default validation of certificates. Certificates are not checked for revocation and will be rejected if invalid.
        CheckRevocationList -- Cerftificate Revocation Lists are checked and certificate will be rejected if revoked or invalid.
        Debug -- Certificate Revocation Lists are checked and revocation will result in rejection. Invalid certificates will be accepted. Certificate validation
                 information is logged and can be retrieved from the certificate handler.
    .EXAMPLE
    Set-CertificateValidationMode Debug
    .PARAMETER Mode
    The mode for certificate validation.
    #>
    [CmdletBinding(SupportsShouldProcess = $false)]
    param
    (
        [Parameter()]
        [ValidateSet('Default', 'CheckRevocationList', 'Debug')]
        [string] $Mode
    )

    begin
    {
        $isValidatorClassLoaded = (([System.AppDomain]::CurrentDomain.GetAssemblies() | ?{ $_.GlobalAssemblyCache -eq $false }) | ?{ $_.DefinedTypes.FullName -contains 'CertificateValidation.CertificateValidator' }) -ne $null

        if ($isValidatorClassLoaded -eq $false)
        {
            Add-Type -TypeDefinition $CertificateValidatorClass
        }
    }

    process
    {
        switch ($Mode)
        {
            'Debug'
            {
                [System.Net.ServicePointManager]::CheckCertificateRevocationList = $true
                [CertificateValidation.CertificateValidator]::SetDebugCertificateValidation()
            }
            'CheckRevocationList'
            {
                [System.Net.ServicePointManager]::CheckCertificateRevocationList = $true
                [CertificateValidation.CertificateValidator]::SetDefaultCertificateValidation()
            }
            'Default'
            {
                [System.Net.ServicePointManager]::CheckCertificateRevocationList = $false
                [CertificateValidation.CertificateValidator]::SetDefaultCertificateValidation()
            }
        }
    }
}

function Clear-CertificateValidationResults
{
    <#
    .SYNOPSIS
    Clears the collection of certificate validation results.
    .DESCRIPTION
    Clears the collection of certificate validation results.
    .EXAMPLE
    Get-CertificateValidationResults
    #>
    [CmdletBinding(SupportsShouldProcess = $false)]
    param()

    begin
    {
        $isValidatorClassLoaded = (([System.AppDomain]::CurrentDomain.GetAssemblies() | ?{ $_.GlobalAssemblyCache -eq $false }) | ?{ $_.DefinedTypes.FullName -contains 'CertificateValidation.CertificateValidator' }) -ne $null

        if ($isValidatorClassLoaded -eq $false)
        {
            Add-Type -TypeDefinition $CertificateValidatorClass
        }
    }

    process
    {
        [CertificateValidation.CertificateValidator]::ClearCertificateValidationResults()
        Sleep -Milliseconds 20
    }
}

function Get-CertificateValidationResults
{
    <#
    .SYNOPSIS
    Gets the certificate validation results for all operations performed in the PowerShell session since the Debug cerificate validation mode was enabled.
    .DESCRIPTION
    Gets the certificate validation results for all operations performed in the PowerShell session since the Debug certificate validation mode was enabled in reverse chronological order.
    .EXAMPLE
    Get-CertificateValidationResults
    #>
    [CmdletBinding(SupportsShouldProcess = $false)]
    param()

    begin
    {
        $isValidatorClassLoaded = (([System.AppDomain]::CurrentDomain.GetAssemblies() | ?{ $_.GlobalAssemblyCache -eq $false }) | ?{ $_.DefinedTypes.FullName -contains 'CertificateValidation.CertificateValidator' }) -ne $null

        if ($isValidatorClassLoaded -eq $false)
        {
            Add-Type -TypeDefinition $CertificateValidatorClass
        }
    }

    process
    {
        return [CertificateValidation.CertificateValidator]::CertificateValidationResults
    }
}

function Test-WebUrl
{
    <#
    .SYNOPSIS
    Tests and reports information about the provided web URL.
    .DESCRIPTION
    Tests a web URL and reports the time taken to get and process the request and response, the HTTP status, and the error message if an error occurred.
    .EXAMPLE
    Test-WebUrl 'http://websitetotest.com/'
    .EXAMPLE
    'https://websitetotest.com/' | Test-WebUrl
    .PARAMETER HostName
    The Hostname to add to the back connection hostnames list.
    .PARAMETER UseDefaultCredentials
    If present the default Windows credential will be used to attempt to authenticate to the URL; otherwise, no credentials will be presented.
    #>
    [CmdletBinding()]
    param
    (
        [Parameter(Mandatory = $true, ValueFromPipeline = $true)]
        [Uri] $Url,
        [Parameter()]
        [Microsoft.PowerShell.Commands.WebRequestMethod] $Method = 'Get',
        [Parameter()]
        [switch] $UseDefaultCredentials
    )

    process
    {
        [bool] $succeeded = $false
        [string] $statusCode = $null
        [string] $statusDescription = $null
        [string] $message = $null
        [int] $bytesReceived = 0
        [Timespan] $timeTaken = [Timespan]::Zero 

        $timeTaken = Measure-Command `
            {
                try
                {
                    [Microsoft.PowerShell.Commands.HtmlWebResponseObject] $response = Invoke-WebRequest -UseDefaultCredentials:$UseDefaultCredentials -Method $Method -Uri $Url
                    $succeeded = $true
                    $statusCode = $response.StatusCode.ToString('D')
                    $statusDescription = $response.StatusDescription
                    $bytesReceived = $response.RawContent.Length

                    Write-Verbose "$($Url.ToString()): $($statusCode) $($statusDescription) $($message)"
                }
                catch [System.Net.WebException]
                {
                    $message = $Error[0].Exception.Message
                    [System.Net.HttpWebResponse] $exceptionResponse = $Error[0].Exception.GetBaseException().Response

                    if ($exceptionResponse -ne $null)
                    {
                        $statusCode = $exceptionResponse.StatusCode.ToString('D')
                        $statusDescription = $exceptionResponse.StatusDescription
                        $bytesReceived = $exceptionResponse.ContentLength

                        if ($statusCode -in '401', '403', '404')
                        {
                            $succeeded = $true
                        }
                    }
                    else
                    {
                        Write-Warning "$($Url.ToString()): $($message)"
                    }
                }
            }

        return [PSCustomObject] @{ Url = $Url; Succeeded = $succeeded; BytesReceived = $bytesReceived; TimeTaken = $timeTaken.TotalMilliseconds; StatusCode = $statusCode; StatusDescription = $statusDescription; Message = $message; }
    }
}

Set-CertificateValidationMode Debug
Clear-CertificateValidationResults

Write-Host 'Testing web sites:'
'https://expired.badssl.com/', 'https://wrong.host.badssl.com/', 'https://self-signed.badssl.com/', 'https://untrusted-root.badssl.com/', 'https://revoked.badssl.com/', 'https://pinning-test.badssl.com/', 'https://sha1-intermediate.badssl.com/' | Test-WebUrl | ft -AutoSize

Write-Host 'Certificate validation results (most recent first):'
Get-CertificateValidationResults | ft -AutoSize

How do you create a hidden div that doesn't create a line break or horizontal space?

Show / hide by mouse click:

<script language="javascript">

    function toggle() {

        var ele = document.getElementById("toggleText");
        var text = document.getElementById("displayText");

        if (ele.style.display == "block") {

            ele.style.display = "none";
            text.innerHTML = "show";
        }
        else {

            ele.style.display = "block";
            text.innerHTML = "hide";
        }
    }
</script>

<a id="displayText" href="javascript:toggle();">show</a> <== click Here

<div id="toggleText" style="display: none"><h1>peek-a-boo</h1></div>

Source: Here

How to access a preexisting collection with Mongoose?

You can do something like this, than you you'll access the native mongodb functions inside mongoose:

var mongoose = require("mongoose");
mongoose.connect('mongodb://localhost/local');

var connection = mongoose.connection;

connection.on('error', console.error.bind(console, 'connection error:'));
connection.once('open', function () {

    connection.db.collection("YourCollectionName", function(err, collection){
        collection.find({}).toArray(function(err, data){
            console.log(data); // it will print your collection data
        })
    });

});

How to have Java method return generic list of any type?

You can use the old way:

public List magicalListGetter() {
    List list = doMagicalVooDooHere();

    return list;
}

or you can use Object and the parent class of everything:

public List<Object> magicalListGetter() {
    List<Object> list = doMagicalVooDooHere();

    return list;
}

Note Perhaps there is a better parent class for all the objects you will put in the list. For example, Number would allow you to put Double and Integer in there.

What is the purpose of the single underscore "_" variable in Python?

_ has 3 main conventional uses in Python:

  1. To hold the result of the last executed expression(/statement) in an interactive interpreter session (see docs). This precedent was set by the standard CPython interpreter, and other interpreters have followed suit

  2. For translation lookup in i18n (see the gettext documentation for example), as in code like

    raise forms.ValidationError(_("Please enter a correct username"))
    
  3. As a general purpose "throwaway" variable name:

    1. To indicate that part of a function result is being deliberately ignored (Conceptually, it is being discarded.), as in code like:

      label, has_label, _ = text.partition(':')
      
    2. As part of a function definition (using either def or lambda), where the signature is fixed (e.g. by a callback or parent class API), but this particular function implementation doesn't need all of the parameters, as in code like:

      def callback(_):
          return True
      

      [For a long time this answer didn't list this use case, but it came up often enough, as noted here, to be worth listing explicitly.]

    This use case can conflict with the translation lookup use case, so it is necessary to avoid using _ as a throwaway variable in any code block that also uses it for i18n translation (many folks prefer a double-underscore, __, as their throwaway variable for exactly this reason).

    Linters often recognize this use case. For example year, month, day = date() will raise a lint warning if day is not used later in the code. The fix, if day is truly not needed, is to write year, month, _ = date(). Same with lambda functions, lambda arg: 1.0 creates a function requiring one argument but not using it, which will be caught by lint. The fix is to write lambda _: 1.0. An unused variable is often hiding a bug/typo (e.g. set day but use dya in the next line).

How do I bind onchange event of a TextBox using JQuery?

You must change the event name from "change" to "onchange":

$(document).ready(function(){
        $("input#tags").bind("onchange", autoFill);
          });

or use the shortcut binder method change:

$(document).ready(function(){
        $("input#tags").change(autoFill);
          });

Note that the onchange event usually fires when the user leave the input, so for auto-complete you better use the keydown event.

Export DataBase with MySQL Workbench with INSERT statements

You can do it using mysqldump tool in command-line:

mysqldump your_database_name > script.sql

This creates a file with database create statements together with insert statements.

More info about options for mysql dump: https://dev.mysql.com/doc/refman/5.7/en/mysqldump-sql-format.html

Non-Static method cannot be referenced from a static context with methods and variables

You should place Scanner input = new Scanner (System.in); into the main method rather than creating the input object outside.

Switch tabs using Selenium WebDriver with Java

Set<String> tabs = driver.getWindowHandles();
Iterator<String> it = tabs.iterator();
tab1 = it.next();
tab2 = it.next();
driver.switchTo().window(tab1);
driver.close();
driver.switchTo().window(tab2);

Try this. It should work

Python Requests and persistent sessions

Save only required cookies and reuse them.

import os
import pickle
from urllib.parse import urljoin, urlparse

login = '[email protected]'
password = 'secret'
# Assuming two cookies are used for persistent login.
# (Find it by tracing the login process)
persistentCookieNames = ['sessionId', 'profileId']
URL = 'http://example.com'
urlData = urlparse(URL)
cookieFile = urlData.netloc + '.cookie'
signinUrl = urljoin(URL, "/signin")
with requests.Session() as session:
    try:
        with open(cookieFile, 'rb') as f:
            print("Loading cookies...")
            session.cookies.update(pickle.load(f))
    except Exception:
        # If could not load cookies from file, get the new ones by login in
        print("Login in...")
        post = session.post(
            signinUrl,
            data={
                'email': login,
                'password': password,
            }
        )
        try:
            with open(cookieFile, 'wb') as f:
                jar = requests.cookies.RequestsCookieJar()
                for cookie in session.cookies:
                    if cookie.name in persistentCookieNames:
                        jar.set_cookie(cookie)
                pickle.dump(jar, f)
        except Exception as e:
            os.remove(cookieFile)
            raise(e)
    MyPage = urljoin(URL, "/mypage")
    page = session.get(MyPage)

Determine version of Entity Framework I am using?

can check it in packages.config file.

<?xml version="1.0" encoding="utf-8"?>
<packages>
<package id="EntityFramework" version="6.0.2" targetFramework="net40-Client" />
</packages> 

Why does Java have an "unreachable statement" compiler error?

It is Nanny. I feel .Net got this one right - it raises a warning for unreachable code, but not an error. It is good to be warned about it, but I see no reason to prevent compilation (especially during debugging sessions where it is nice to throw a return in to bypass some code).

Select rows which are not present in other table

this can also be tried...

SELECT l.ip, tbl2.ip as ip2, tbl2.hostname
FROM   login_log l 
LEFT   JOIN (SELECT ip_location.ip, ip_location.hostname
             FROM ip_location
             WHERE ip_location.ip is null)tbl2

Is there a Pattern Matching Utility like GREP in Windows?

GnuWin32 is worth mentioning, it provides native Win32 version of all standard linux tools, including grep, file, sed, groff, indent, etc.

And it's constantly updated when new versions of these tools are released.

How can I completely remove TFS Bindings

Next works for me:

  1. Delete all .vssscc (solution binding) and .vspscc (project binding) files
  2. Remove block GlobalSection(TeamFoundationVersionControl) = preSolution from solution file

There could be also information regarding source control in the proj file in tags

<SccProjectName>SAK</SccProjectName> <SccLocalPath>SAK</SccLocalPath> <SccAuxPath>SAK</SccAuxPath> <SccProvider>SAK</SccProvider>

SAK states for "Should Already Know", so it can be kept.

Solutions for INSERT OR UPDATE on SQL Server

In SQL Server 2008 you can use the MERGE statement

Capturing count from an SQL query

You'll get converting errors with:

cmd.CommandText = "SELECT COUNT(*) FROM table_name";
Int32 count = (Int32) cmd.ExecuteScalar();

Use instead:

string stm = "SELECT COUNT(*) FROM table_name WHERE id="+id+";";
MySqlCommand cmd = new MySqlCommand(stm, conn);
Int32 count = Convert.ToInt32(cmd.ExecuteScalar());
if(count > 0){
    found = true; 
} else {
    found = false; 
}

How to check if a value is not null and not empty string in JS

Instead of using

if(data !== null && data !== ''  && data!==undefined) {

// do something
}

You can use below simple code

if(Boolean(value)){ 
// do something 
}
  • Values that are intuitively “empty”, like 0, an empty string, null, undefined, and NaN, become false
  • Other values become true

Is there a better way to iterate over two lists, getting one element from each list for each iteration?

in case your Latitude and Longitude lists are large and lazily loaded:

from itertools import izip
for lat, lon in izip(latitudes, longitudes):
    process(lat, lon)

or if you want to avoid the for-loop

from itertools import izip, imap
out = imap(process, izip(latitudes, longitudes))

Find and extract a number from a string

var outputString = String.Join("", inputString.Where(Char.IsDigit));

Get all numbers in the string. So if you use for examaple '1 plus 2' it will get '12'.

Selenium Webdriver: Entering text into text field

It might be the JavaScript check for some valid condition.
Two things you can perform a/c to your requirements:

  1. either check for the valid string-input in the text-box.
  2. or set a loop against that text box to enter the value until you post the form/request.
String barcode="0000000047166";

WebElement strLocator = driver.findElement(By.xpath("//*[@id='div-barcode']"));
strLocator.sendKeys(barcode);

Default session timeout for Apache Tomcat applications

Open $CATALINA_BASE/conf/web.xml and find this

<!-- ==================== Default Session Configuration ================= -->
<!-- You can set the default session timeout (in minutes) for all newly   -->
<!-- created sessions by modifying the value below.                       -->

<session-config>
  <session-timeout>30</session-timeout>
</session-config>

all webapps implicitly inherit from this default web descriptor. You can override session-config as well as other settings defined there in your web.xml.

This is actually from my Tomcat 7 (Windows) but I think 5.5 conf is not very different

Get first line of a shell command's output

I would use:

awk 'FNR <= 1' file_*.txt

As @Kusalananda points out there are many ways to capture the first line in command line but using the head -n 1 may not be the best option when using wildcards since it will print additional info. Changing 'FNR == i' to 'FNR <= i' allows to obtain the first i lines.

For example, if you have n files named file_1.txt, ... file_n.txt:

awk 'FNR <= 1' file_*.txt

hello
...
bye

But with head wildcards print the name of the file:

head -1 file_*.txt

==> file_1.csv <==
hello
...
==> file_n.csv <==
bye

@Html.DropDownListFor how to set default value

Like this:

@Html.DropDownListFor(model => model.Status, new List<SelectListItem> 
       { new SelectListItem{Text="Active", Value="True"},
         new SelectListItem{Text="Deactive", Value="False"}},"Select One")

If you want Active to be selected by default then use Selected property of SelectListItem:

@Html.DropDownListFor(model => model.Status, new List<SelectListItem> 
           { new SelectListItem{Text="Active", Value="True",Selected=true},
             new SelectListItem{Text="Deactive", Value="False"}},"Select One")

If using SelectList, then you have to use this overload and specify SelectListItem Value property which you want to set selected:

@Html.DropDownListFor(model => model.title, 
                     new SelectList(new List<SelectListItem>
  {
      new SelectListItem { Text = "Active" , Value = "True"},
      new SelectListItem { Text = "InActive", Value = "False" }
  },
    "Value", // property to be set as Value of dropdown item
    "Text",  // property to be used as text of dropdown item
    "True"), // value that should be set selected of dropdown
     new { @class = "form-control" })

window.location.href doesn't redirect

window.location.href wasn't working in Android. I cleared cache in Android Chrome and it works fine. Suggest trying this first before getting involved in various coding.

How to find largest objects in a SQL Server database?

In SQL Server 2008, you can also just run the standard report Disk Usage by Top Tables. This can be found by right clicking the DB, selecting Reports->Standard Reports and selecting the report you want.

WPF: ItemsControl with scrollbar (ScrollViewer)

To get a scrollbar for an ItemsControl, you can host it in a ScrollViewer like this:

<ScrollViewer VerticalScrollBarVisibility="Auto">
  <ItemsControl>
    <uc:UcSpeler />
    <uc:UcSpeler />
    <uc:UcSpeler />
    <uc:UcSpeler />
    <uc:UcSpeler />
  </ItemsControl>
</ScrollViewer>

Error creating bean with name

It looks like your Spring component scan Base is missing UserServiceImpl

<context:component-scan base-package="org.assessme.com.controller." />

Add tooltip to font awesome icon

You should use 'title' attribute along with 'data-toogle' (bootstrap).

For example

<i class="fa fa-info" data-toggle="tooltip" title="Hooray!"></i>Hover over me

and do not forget to add the javascript to display the tooltip

<script>
    $(document).ready(function(){
        $('[data-toggle="tooltip"]').tooltip();   
    });
</script>

How do I write data to csv file in columns and rows from a list in python?

>>> import csv
>>> with open('test.csv', 'wb') as f:
...     wtr = csv.writer(f, delimiter= ' ')
...     wtr.writerows( [[1, 2], [2, 3], [4, 5]])
...
>>> with open('test.csv', 'r') as f:
...     for line in f:
...         print line,
...
1 2 <<=== Exactly what you said that you wanted.
2 3
4 5
>>>

To get it so that it can be loaded sensibly by Excel, you need to use a comma (the csv default) as the delimiter, unless you are in a locale (e.g. Europe) where you need a semicolon.

Proper way to handle multiple forms on one page in Django

Django's class based views provide a generic FormView but for all intents and purposes it is designed to only handle one form.

One way to handle multiple forms with same target action url using Django's generic views is to extend the 'TemplateView' as shown below; I use this approach often enough that I have made it into an Eclipse IDE template.

class NegotiationGroupMultifacetedView(TemplateView):
    ### TemplateResponseMixin
    template_name = 'offers/offer_detail.html'

    ### ContextMixin 
    def get_context_data(self, **kwargs):
        """ Adds extra content to our template """
        context = super(NegotiationGroupDetailView, self).get_context_data(**kwargs)

        ...

        context['negotiation_bid_form'] = NegotiationBidForm(
            prefix='NegotiationBidForm', 
            ...
            # Multiple 'submit' button paths should be handled in form's .save()/clean()
            data = self.request.POST if bool(set(['NegotiationBidForm-submit-counter-bid',
                                              'NegotiationBidForm-submit-approve-bid',
                                              'NegotiationBidForm-submit-decline-further-bids']).intersection(
                                                    self.request.POST)) else None,
            )
        context['offer_attachment_form'] = NegotiationAttachmentForm(
            prefix='NegotiationAttachment', 
            ...
            data = self.request.POST if 'NegotiationAttachment-submit' in self.request.POST else None,
            files = self.request.FILES if 'NegotiationAttachment-submit' in self.request.POST else None
            )
        context['offer_contact_form'] = NegotiationContactForm()
        return context

    ### NegotiationGroupDetailView 
    def post(self, request, *args, **kwargs):
        context = self.get_context_data(**kwargs)

        if context['negotiation_bid_form'].is_valid():
            instance = context['negotiation_bid_form'].save()
            messages.success(request, 'Your offer bid #{0} has been submitted.'.format(instance.pk))
        elif context['offer_attachment_form'].is_valid():
            instance = context['offer_attachment_form'].save()
            messages.success(request, 'Your offer attachment #{0} has been submitted.'.format(instance.pk))
                # advise of any errors

        else 
            messages.error('Error(s) encountered during form processing, please review below and re-submit')

        return self.render_to_response(context)

The html template is to the following effect:

...

<form id='offer_negotiation_form' class="content-form" action='./' enctype="multipart/form-data" method="post" accept-charset="utf-8">
    {% csrf_token %}
    {{ negotiation_bid_form.as_p }}
    ...
    <input type="submit" name="{{ negotiation_bid_form.prefix }}-submit-counter-bid" 
    title="Submit a counter bid"
    value="Counter Bid" />
</form>

...

<form id='offer-attachment-form' class="content-form" action='./' enctype="multipart/form-data" method="post" accept-charset="utf-8">
    {% csrf_token %}
    {{ offer_attachment_form.as_p }}

    <input name="{{ offer_attachment_form.prefix }}-submit" type="submit" value="Submit" />
</form>

...

How to check whether particular port is open or closed on UNIX?

netstat -ano|grep 443|grep LISTEN

will tell you whether a process is listening on port 443 (you might have to replace LISTEN with a string in your language, though, depending on your system settings).

How to install SignTool.exe for Windows 10

SignTool is available as part of the Windows SDK (which comes with Visual Studio Community 2015). Make sure to select the "ClickOnce Publishing Tools" from the feature list during the installation of Visual Studio 2015 to get the SignTool.

ClickOnce Publishing Tools

Once Visual Studio is installed you can run the signtool command from the Visual Studio Command Prompt.

By default (on Windows 10) the SignTool will be installed in:

  • C:\Program Files (x86)\Windows Kits\10\bin\x86\signtool.exe

How to sort a HashMap in Java

Do you have to use a HashMap? If you only need the Map Interface use a TreeMap


If you want to sort by comparing values in the HashMap. You have to write code to do this, if you want to do it once you can sort the values of your HashMap:

Map<String, Person> people = new HashMap<>();
Person jim = new Person("Jim", 25);
Person scott = new Person("Scott", 28);
Person anna = new Person("Anna", 23);

people.put(jim.getName(), jim);
people.put(scott.getName(), scott);
people.put(anna.getName(), anna);

// not yet sorted
List<Person> peopleByAge = new ArrayList<>(people.values());

Collections.sort(peopleByAge, Comparator.comparing(Person::getAge));

for (Person p : peopleByAge) {
    System.out.println(p.getName() + "\t" + p.getAge());
}

If you want to access this sorted list often, then you could insert your elements into a HashMap<TreeSet<Person>>, though the semantics of sets and lists are a bit different.

Target class controller does not exist - Laravel 8

If you would like to continue using the original auto-prefixed controller routing, you can simply set the value of the $namespace property within your RouteServiceProvider and update the route registrations within the boot method to use the $namespace property:

class RouteServiceProvider extends ServiceProvider
{
    /**
     * This namespace is applied to your controller routes.
     *
     * In addition, it is set as the URL generator's root namespace.
     *
     * @var string
     */
    protected $namespace = 'App\Http\Controllers';

    /**
     * Define your route model bindings, pattern filters, etc.
     *
     * @return void
     */
    public function boot()
    {
        $this->configureRateLimiting();

        $this->routes(function () {
            Route::middleware('web')
                ->namespace($this->namespace)
                ->group(base_path('routes/web.php'));

            Route::prefix('api')
                ->middleware('api')
                ->namespace($this->namespace)
                ->group(base_path('routes/api.php'));
    });
}

Is there any native DLL export functions viewer?

dumpbin from the Visual Studio command prompt:

dumpbin /exports csp.dll

Example of output:

Microsoft (R) COFF/PE Dumper Version 10.00.30319.01
Copyright (C) Microsoft Corporation.  All rights reserved.


Dump of file csp.dll

File Type: DLL

  Section contains the following exports for CSP.dll

    00000000 characteristics
    3B1D0B77 time date stamp Tue Jun 05 12:40:23 2001
        0.00 version
           1 ordinal base
          25 number of functions
          25 number of names

    ordinal hint RVA      name

          1    0 00001470 CPAcquireContext
          2    1 000014B0 CPCreateHash
          3    2 00001520 CPDecrypt
          4    3 000014B0 CPDeriveKey
          5    4 00001590 CPDestroyHash
          6    5 00001590 CPDestroyKey
          7    6 00001560 CPEncrypt
          8    7 00001520 CPExportKey
          9    8 00001490 CPGenKey
         10    9 000015B0 CPGenRandom
         11    A 000014D0 CPGetHashParam
         12    B 000014D0 CPGetKeyParam
         13    C 00001500 CPGetProvParam
         14    D 000015C0 CPGetUserKey
         15    E 00001580 CPHashData
         16    F 000014F0 CPHashSessionKey
         17   10 00001540 CPImportKey
         18   11 00001590 CPReleaseContext
         19   12 00001580 CPSetHashParam
         20   13 00001580 CPSetKeyParam
         21   14 000014F0 CPSetProvParam
         22   15 00001520 CPSignHash
         23   16 000015A0 CPVerifySignature
         24   17 00001060 DllRegisterServer
         25   18 00001000 DllUnregisterServer

  Summary

        1000 .data
        1000 .rdata
        1000 .reloc
        1000 .rsrc
        1000 .text

shell init issue when click tab, what's wrong with getcwd?

This usually occurs when your current directory does not exist anymore. Most likely, from another terminal you remove that directory (from within a script or whatever). To get rid of this, in case your current directory was recreated in the meantime, just cd to another (existing) directory and then cd back; the simplest would be: cd; cd -.

Current user in Magento?

for Email use this code

$email=$this->__('Welcome, %s!', Mage::getSingleton('customer/session')->getCustomer()->getEmail());

echo $email;

Selenium WebDriver findElement(By.xpath()) not working for me

Correct Xpath syntax is like:

//tagname[@value='name']

So you should write something like this:

findElement(By.xpath("//input[@test-id='test-username']"));

How to declare a constant in Java

  1. You can use an enum type in Java 5 and onwards for the purpose you have described. It is type safe.
  2. A is an instance variable. (If it has the static modifier, then it becomes a static variable.) Constants just means the value doesn't change.
  3. Instance variables are data members belonging to the object and not the class. Instance variable = Instance field.

If you are talking about the difference between instance variable and class variable, instance variable exist per object created. While class variable has only one copy per class loader regardless of the number of objects created.

Java 5 and up enum type

public enum Color{
 RED("Red"), GREEN("Green");

 private Color(String color){
    this.color = color;
  }

  private String color;

  public String getColor(){
    return this.color;
  }

  public String toString(){
    return this.color;
  }
}

If you wish to change the value of the enum you have created, provide a mutator method.

public enum Color{
 RED("Red"), GREEN("Green");

 private Color(String color){
    this.color = color;
  }

  private String color;

  public String getColor(){
    return this.color;
  }

  public void setColor(String color){
    this.color = color;
  }

  public String toString(){
    return this.color;
  }
}

Example of accessing:

public static void main(String args[]){
  System.out.println(Color.RED.getColor());

  // or

  System.out.println(Color.GREEN);
}

Python to print out status bar and percentage

For Python 3.6 the following works for me to update the output inline:

for current_epoch in range(10):
    for current_step) in range(100):
        print("Train epoch %s: Step %s" % (current_epoch, current_step), end="\r")
print()

Correct way to initialize empty slice

As an addition to @ANisus' answer...

below is some information from the "Go in action" book, which I think is worth mentioning:

Difference between nil & empty slices

If we think of a slice like this:

[pointer] [length] [capacity]

then:

nil slice:   [nil][0][0]
empty slice: [addr][0][0] // points to an address

nil slice

They’re useful when you want to represent a slice that doesn’t exist, such as when an exception occurs in a function that returns a slice.

// Create a nil slice of integers.
var slice []int

empty slice

Empty slices are useful when you want to represent an empty collection, such as when a database query returns zero results.

// Use make to create an empty slice of integers.
slice := make([]int, 0)

// Use a slice literal to create an empty slice of integers.
slice := []int{}

Regardless of whether you’re using a nil slice or an empty slice, the built-in functions append, len, and cap work the same.


Go playground example:

package main

import (
    "fmt"
)

func main() {

    var nil_slice []int
    var empty_slice = []int{}

    fmt.Println(nil_slice == nil, len(nil_slice), cap(nil_slice))
    fmt.Println(empty_slice == nil, len(empty_slice), cap(empty_slice))

}

prints:

true 0 0
false 0 0

Can someone explain mappedBy in JPA and Hibernate?

By specifying the @JoinColumn on both models you don't have a two way relationship. You have two one way relationships, and a very confusing mapping of it at that. You're telling both models that they "own" the IDAIRLINE column. Really only one of them actually should! The 'normal' thing is to take the @JoinColumn off of the @OneToMany side entirely, and instead add mappedBy to the @OneToMany.

@OneToMany(cascade = CascadeType.ALL, mappedBy="airline")
public Set<AirlineFlight> getAirlineFlights() {
    return airlineFlights;
}

That tells Hibernate "Go look over on the bean property named 'airline' on the thing I have a collection of to find the configuration."

Non greedy (reluctant) regex matching in sed?

sed does not support "non greedy" operator.

You have to use "[]" operator to exclude "/" from match.

sed 's,\(http://[^/]*\)/.*,\1,'

P.S. there is no need to backslash "/".

How do you change the width and height of Twitter Bootstrap's tooltips?

Another solution; create a new class (e.g. tooltip-wide) in CSS:

.tooltip-wide + .tooltip > .tooltip-inner {
     max-width: 100%;
}

Use this class on elements where you want wide tooltips:

<div class="tooltip-wide" data-toggle="tooltip" title="I am a long tooltip">Long tooltip</div>

Bootstrap tooltip generates markup below the element containing the tooltip, so the HTML actually looks something like this after the markup is generated:

<div class="tooltip-wide" data-toggle="tooltip" title="I am a long tooltip">Long tooltip</div>
<div class="tooltip" role="tooltip">
    <div class="tooltip-arrow"></div>
    <div class="tooltip-inner">I am a long tooltip</div>
</div>

The CSS uses this to access the adjacent element (+) to .tooltip-wide, and from there navigates to .tooltip-inner, before applying the max-width attribute. This will only affect elements using the .tooltip-wide class, all other tooltips will remain unaltered.

How can I make a time delay in Python?

While everyone else has suggested the de facto time module, I thought I'd share a different method using matplotlib's pyplot function, pause.

An example

from matplotlib import pyplot as plt
plt.pause(5)    # Pauses the program for 5 seconds

Typically this is used to prevent the plot from disappearing as soon as it is plotted or to make crude animations.

This would save you an import if you already have matplotlib imported.

HTTP vs HTTPS performance

Here's a great article (a little bit old, but still great) on SSL handshake latency. Helped me identifying SSL as the main cause of slowness for clients who were using my app through slow Internet connections:

http://www.semicomplete.com/blog/geekery/ssl-latency.html

Get scroll position using jquery

Use scrollTop() to get or set the scroll position.

Facebook Android Generate Key Hash

Try passing the password for the key and store as part of the command

keytool -exportcert -alias androiddebugkey -keystore ~/.android/debug.keystore -keypass android -storepass android \
| openssl sha1 -binary \
| openssl base64

Is it possible to get multiple values from a subquery?

Can't you use JOIN like this one?

SELECT
a.x , b.y, b.z 
FROM a 
LEFT OUTER JOIN b ON b.v = a.v

(I don't know Oracle Syntax. So I wrote SQL syntax)

How do I split a string so I can access item x?

What about using string and values() statement?

DECLARE @str varchar(max)
SET @str = 'Hello John Smith'

DECLARE @separator varchar(max)
SET @separator = ' '

DECLARE @Splited TABLE(id int IDENTITY(1,1), item varchar(max))

SET @str = REPLACE(@str, @separator, '''),(''')
SET @str = 'SELECT * FROM (VALUES(''' + @str + ''')) AS V(A)' 

INSERT INTO @Splited
EXEC(@str)

SELECT * FROM @Splited

Result-set achieved.

id  item
1   Hello
2   John
3   Smith