How to run a single RSpec test?

You can do something like this:

 rspec/spec/features/controller/spec_file_name.rb
 rspec/spec/features/controller_name.rb         #run all the specs in this controller

Cannot install packages inside docker Ubuntu image

I found that mounting a local volume over /tmp can cause permission issues when the "apt-get update" runs, which prevents the package cache from being populated. Hopefully, this isn't something most people do, but it's something else to look for if you see this issue.

Java way to check if a string is palindrome

public static boolean istPalindrom(char[] word){
int i1 = 0;
int i2 = word.length - 1;
while (i2 > i1) {
    if (word[i1] != word[i2]) {
        return false;
    }
    ++i1;
    --i2;
}
return true;
}

Error to use a section registered as allowDefinition='MachineToApplication' beyond application level

Add Favicon to Website

This is not done in PHP. It's part of the <head> tags in a HTML page.
That icon is called a favicon. According to Wikipedia:

A favicon (short for favorites icon), also known as a shortcut icon, website icon, URL icon, or bookmark icon is a 16×16 or 32×32 pixel square icon associated with a particular website or webpage.
Adding it is easy. Just add an .ico image file that is either 16x16 pixels or 32x32 pixels. Then, in the web pages, add <link rel="shortcut icon" href="favicon.ico" type="image/x-icon"> to the <head> element.
You can easily generate favicons here.

In Java, what is the best way to determine the size of an object?

I accidentally found a java class "jdk.nashorn.internal.ir.debug.ObjectSizeCalculator", already in jdk, which is easy to use and seems quite useful for determining the size of an object.

System.out.println(ObjectSizeCalculator.getObjectSize(new gnu.trove.map.hash.TObjectIntHashMap<String>(12000, 0.6f, -1)));
System.out.println(ObjectSizeCalculator.getObjectSize(new HashMap<String, Integer>(100000)));
System.out.println(ObjectSizeCalculator.getObjectSize(3));
System.out.println(ObjectSizeCalculator.getObjectSize(new int[]{1, 2, 3, 4, 5, 6, 7 }));
System.out.println(ObjectSizeCalculator.getObjectSize(new int[100]));

results:

Find the least number of coins required that can make any change from 1 to 99 cents

On the one hand, this has been answered. On the other hand, most of the answers require many lines of code. This Python answer does not require many lines of code, merely many lines of thought ^_^ :

div_round_up = lambda a, b: a // b if a % b == 0 else a // b + 1

def optimum_change(*coins):
    wallet = [0 for i in range(0, len(coins) - 1)]
    for j in range(0, len(wallet)):
        target = coins[j + 1] - 1 
        target -= sum(wallet[i] * coins[i] for i in range(0, j))
        wallet[j] = max(0, div_round_up(target, coins[j]))
    return wallet

optimum_change(1, 5, 10, 25, 100)
#  [4, 1, 2, 3]

This is a very simple rescaling algorithm that may perhaps break for inputs which I haven't considered yet, but I think it should be robust. It basically says, "to add a new coin type to the wallet, peek at the next coin type N, then add the amount of new coins necessary to make target = N - 1." It calculates that you need at least ceil((target - wallet_value)/coin_value) to do so, and does not check if this will also make every number in between. Notice that the syntax encodes the "from 0 to 99 cents" by appending the final number "100" since that yields the appropriate final target.

The reason it does not check is something like, "if it can, it automatically will." Put more directly, once you do this step for a penny (value 1), the algorithm can "break" a nickel (value 5) into any subinterval 0 - 4. Once you do it for a nickel, the algorithm can now "break" a dime (value 10). And so on.

Of course, it does not require those particular inputs; you can use strange currencies too:

>>> optimum_change(1, 4, 7, 8, 100)
[3, 1, 0, 12]

Notice how it automatically ignores the 7 coin because it knows it can already "break" 8's with the change it has.

Count all values in a matrix greater than a value

You can use numpy.count_nonzero, converting the whole into a one-liner:

za = numpy.count_nonzero(numpy.asarray(o31)<200)  #as written in the code

C# DataRow Empty-check

public static bool AreAllCellsEmpty(DataRow row)
{
  if (row == null) throw new ArgumentNullException("row");

  for (int i = row.Table.Columns.Count - 1; i >= 0; i--)
    if (!row.IsNull(i))
      return false;

  return true;
}

HTML Display Current date

Use Date::toLocaleDateString.

new Date().toLocaleDateString()
= "9/13/2015"

You don't need to set innerHTML, just by writing

<p>
<script> document.write(new Date().toLocaleDateString()); </script>
</p>

will work.

P.S.

new Date().toDateString()
= "Sun Sep 13 2015"

Cell spacing in UICollectionView

Using a horizontal flow layout, I was also getting a 10 points spacing between cells. To remove the spacing I needed to set minimumLineSpacing as well as minimumInterItemSpacing to zero.

UICollectionViewFlowLayout *flow = [[UICollectionViewFlowLayout alloc] init];
flow.itemSize = CGSizeMake(cellWidth, cellHeight);
flow.scrollDirection = UICollectionViewScrollDirectionHorizontal;
flow.minimumInteritemSpacing = 0;
flow.minimumLineSpacing = 0;

Also, if all your cells are the same size, it's simpler and more efficient to set the property on the flow layout directly instead of using delegate methods.

Setting device orientation in Swift iOS

I've been struggling all morning to get ONLY landscape left/right supported properly. I discovered something really annoying; although the "General" tab allows you to deselect "Portrait" for device orientation, you have to edit the plist itself to disable Portrait and PortraitUpsideDown INTERFACE orientations - it's the last key in the plist: "Supported Interface Orientations".

The other thing is that it seems you must use the "mask" versions of the enums (e.g., UIInterfaceOrientationMask.LandscapeLeft), not just the orientation one. The code that got it working for me (in my main viewController):

override func shouldAutorotate() -> Bool {
    return true
}

override func supportedInterfaceOrientations() -> Int {
    return Int(UIInterfaceOrientationMask.LandscapeLeft.rawValue) | Int(UIInterfaceOrientationMask.LandscapeRight.rawValue)
}

Making this combination of plist changes and code is the only way I've been able to get it working properly.

How to write to file in Ruby?

You can use the short version:

File.write('/path/to/file', 'Some glorious content')

It returns the length written; see ::write for more details and options.

To append to the file, if it already exists, use:

File.write('/path/to/file', 'Some glorious content', mode: 'a')

Java: Rotating Images

AffineTransform instances can be concatenated (added together). Therefore you can have a transform that combines 'shift to origin', 'rotate' and 'shift back to desired position'.

What does if [ $? -eq 0 ] mean for shell scripts?

$? is the exit status of the most recently-executed command; by convention, 0 means success and anything else indicates failure. That line is testing whether the grep command succeeded.

The grep manpage states:

The exit status is 0 if selected lines are found, and 1 if not found. If an error occurred the exit status is 2. (Note: POSIX error handling code should check for '2' or greater.)

So in this case it's checking whether any ERROR lines were found.

How to cast List<Object> to List<MyClass>

You should just iterate over the list and cast all Objects one by one

how to set start value as "0" in chartjs?

For Chart.js 2.*, the option for the scale to begin at zero is listed under the configuration options of the linear scale. This is used for numerical data, which should most probably be the case for your y-axis. So, you need to use this:

options: {
    scales: {
        yAxes: [{
            ticks: {
                beginAtZero: true
            }
        }]
    }
}

A sample line chart is also available here where the option is used for the y-axis. If your numerical data is on the x-axis, use xAxes instead of yAxes. Note that an array (and plural) is used for yAxes (or xAxes), because you may as well have multiple axes.

Sending private messages to user

If you want to send the message to a predetermined person, such as yourself, you can set it so that the channel it would be messaging to would be their (your) own userID. So for instance, if you're using the discord bot tutorials from Digital Trends, where it says "to: ", you would continue with their (or your) userID. For instance, with how that specific code is set up, you could do "to: userID", and it would message that person. Or, if you want the bot to message you any time someone uses a specific command, you could do "to: '12345678890'", the numbers being a filler for the actual userID. Hope this helps!

Reverse engineering from an APK file to a project

In Android Studio 3.5, It's soo easy that you can just achieve it in a minute. following is a step wise process.

1: Open Android Studio, Press window button -> Type Android Studio -> click on icon to open android studio splash screen which will look like this.

2: Here you can see an option "Profile or debug APK" click on it and select your apk file and press ok.

3: It will open all your manifest and java classes with in a minute depending upon size of apk.

That's it.

How to set Google Chrome in WebDriver

It was giving Illegal Exception.

My workaround with code:

public void dofirst(){
    System.setProperty("webdriver.chrome.driver","D:\\Softwares\\selenium\\chromedriver_win32\\chromedriver.exe");
    WebDriver driver = new ChromeDriver();
    driver.get("http://www.facebook.com");
}

Create a one to many relationship using SQL Server

This is how I usually do it (sql server).

Create Table Master (
MasterID int identity(1,1) primary key,
Stuff varchar(10)
)
GO
Create Table Detail (
DetailID int identity(1,1) primary key,
MasterID int references Master, --use 'references'
Stuff varchar(10))
GO
Insert into Master values('value')
--(1 row(s) affected)
GO
Insert into Detail values (1, 'Value1') -- Works
--(1 row(s) affected)
insert into Detail values (2, 'Value2') -- Fails
--Msg 547, Level 16, State 0, Line 2
--The INSERT statement conflicted with the FOREIGN KEY constraint "FK__Detail__MasterID__0C70CFB4". 
--The conflict occurred in database "Play", table "dbo.Master", column 'MasterID'.
--The statement has been terminated.

As you can see the second insert into the detail fails because of the foreign key. Here's a good weblink that shows various syntax for defining FK during table creation or after.

http://www.1keydata.com/sql/sql-foreign-key.html

java.lang.ClassNotFoundException: com.mysql.jdbc.Driver in Eclipse

You will have to include driver jar for MySQL MySQL Connector Jar in your classpath.

If you are using Eclipse: How to add dependent libraries in Eclipse

If you are using command line include the path to the driver jar using the -cp parameter of java.

java -cp C:\lib\* Main

Scroll to bottom of Div on page load (jQuery)

for animate in jquery (version > 2.0)

var d = $('#div1');
d.animate({ scrollTop: d.prop('scrollHeight') }, 1000);

How to increase Maximum Upload size in cPanel?

Then go to Software -> MultiPHP INI Editor

Then select the php version from the dropdown, then scroll down for the upload_max_filesize which will be 2M by default, now increase it according to your need.

Also enable the file_uploads for HTTP file uploads for convenience.

If you don't have access to WHM, then follow the .htaccess method.

Ignoring upper case and lower case in Java

Use String#toLowerCase() or String#equalsIgnoreCase() methods

Some examples:

    String abc    = "Abc".toLowerCase();
    boolean isAbc = "Abc".equalsIgnoreCase("ABC");

creating triggers for After Insert, After Update and After Delete in SQL

(Update: overlooked a fault in the matter, I have corrected)

(Update2: I wrote from memory the code screwed up, repaired it)

(Update3: check on SQLFiddle)

create table Derived_Values
  (
    BusinessUnit nvarchar(100) not null
    ,Questions nvarchar(100) not null
    ,Answer nvarchar(100)
    )

go

ALTER TABLE Derived_Values ADD CONSTRAINT PK_Derived_Values
PRIMARY KEY CLUSTERED (BusinessUnit, Questions);

create table Derived_Values_Test
  (
    BusinessUnit nvarchar(150)
    ,Questions nvarchar(100)
    ,Answer nvarchar(100)
    )

go

CREATE TRIGGER trgAfterUpdate ON  [Derived_Values]
FOR UPDATE
AS  
begin
    declare @BusinessUnit nvarchar(50)
    set @BusinessUnit = 'Updated Record -- After Update Trigger.'

    insert into 
        [Derived_Values_Test]
        --(BusinessUnit,Questions, Answer) 
    SELECT 
        @BusinessUnit + i.BusinessUnit, i.Questions, i.Answer
    FROM 
        inserted i
        inner join deleted d on i.BusinessUnit = d.BusinessUnit
end

go

CREATE TRIGGER trgAfterDelete ON  [Derived_Values]
FOR UPDATE
AS  
begin
    declare @BusinessUnit nvarchar(50)
    set @BusinessUnit = 'Deleted Record -- After Delete Trigger.'

    insert into 
        [Derived_Values_Test]
        --(BusinessUnit,Questions, Answer) 
    SELECT 
        @BusinessUnit + d.BusinessUnit, d.Questions, d.Answer
    FROM 
        deleted d
end

go

insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU1', 'Q11', 'A11')
insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU1', 'Q12', 'A12')
insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU2', 'Q21', 'A21')
insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU2', 'Q22', 'A22')

UPDATE Derived_Values SET Answer='Updated Answers A11' from Derived_Values WHERE (BusinessUnit = 'BU1') AND (Questions = 'Q11');
UPDATE Derived_Values SET Answer='Updated Answers A12' from Derived_Values WHERE (BusinessUnit = 'BU1') AND (Questions = 'Q12');
UPDATE Derived_Values SET Answer='Updated Answers A21' from Derived_Values WHERE (BusinessUnit = 'BU2') AND (Questions = 'Q21');
UPDATE Derived_Values SET Answer='Updated Answers A22' from Derived_Values WHERE (BusinessUnit = 'BU2') AND (Questions = 'Q22');

delete Derived_Values;

and then:

SELECT * FROM Derived_Values;
go

select * from Derived_Values_Test;


Record Count: 0;

BUSINESSUNIT    QUESTIONS   ANSWER
Updated Record -- After Update Trigger.BU1  Q11 Updated Answers A11
Deleted Record -- After Delete Trigger.BU1  Q11 A11
Updated Record -- After Update Trigger.BU1  Q12 Updated Answers A12
Deleted Record -- After Delete Trigger.BU1  Q12 A12
Updated Record -- After Update Trigger.BU2  Q21 Updated Answers A21
Deleted Record -- After Delete Trigger.BU2  Q21 A21
Updated Record -- After Update Trigger.BU2  Q22 Updated Answers A22
Deleted Record -- After Delete Trigger.BU2  Q22 A22

(Update4: If you want to sync: SQLFiddle)

create table Derived_Values
  (
    BusinessUnit nvarchar(100) not null
    ,Questions nvarchar(100) not null
    ,Answer nvarchar(100)
    )

go

ALTER TABLE Derived_Values ADD CONSTRAINT PK_Derived_Values
PRIMARY KEY CLUSTERED (BusinessUnit, Questions);

create table Derived_Values_Test
  (
    BusinessUnit nvarchar(150) not null
    ,Questions nvarchar(100) not null
    ,Answer nvarchar(100)
    )

go

ALTER TABLE Derived_Values_Test ADD CONSTRAINT PK_Derived_Values_Test
PRIMARY KEY CLUSTERED (BusinessUnit, Questions);

CREATE TRIGGER trgAfterInsert ON  [Derived_Values]
FOR INSERT
AS  
begin
    insert
        [Derived_Values_Test]
        (BusinessUnit,Questions,Answer)
    SELECT 
        i.BusinessUnit, i.Questions, i.Answer
    FROM 
        inserted i
end

go


CREATE TRIGGER trgAfterUpdate ON  [Derived_Values]
FOR UPDATE
AS  
begin
    declare @BusinessUnit nvarchar(50)
    set @BusinessUnit = 'Updated Record -- After Update Trigger.'

    update
        [Derived_Values_Test]
    set
        --BusinessUnit = i.BusinessUnit
        --,Questions = i.Questions
        Answer = i.Answer
    from
        [Derived_Values]
        inner join inserted i 
    on
        [Derived_Values].BusinessUnit = i.BusinessUnit
        and
        [Derived_Values].Questions = i.Questions
end

go

CREATE TRIGGER trgAfterDelete ON  [Derived_Values]
FOR DELETE
AS  
begin
    delete 
        [Derived_Values_Test]
    from
        [Derived_Values_Test]
        inner join deleted d 
    on
        [Derived_Values_Test].BusinessUnit = d.BusinessUnit
        and
        [Derived_Values_Test].Questions = d.Questions
end

go

insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU1', 'Q11', 'A11')
insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU1', 'Q12', 'A12')
insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU2', 'Q21', 'A21')
insert Derived_Values (BusinessUnit,Questions, Answer) values ('BU2', 'Q22', 'A22')

UPDATE Derived_Values SET Answer='Updated Answers A11' from Derived_Values WHERE (BusinessUnit = 'BU1') AND (Questions = 'Q11');
UPDATE Derived_Values SET Answer='Updated Answers A12' from Derived_Values WHERE (BusinessUnit = 'BU1') AND (Questions = 'Q12');
UPDATE Derived_Values SET Answer='Updated Answers A21' from Derived_Values WHERE (BusinessUnit = 'BU2') AND (Questions = 'Q21');
UPDATE Derived_Values SET Answer='Updated Answers A22' from Derived_Values WHERE (BusinessUnit = 'BU2') AND (Questions = 'Q22');

--delete Derived_Values;

And then:

SELECT * FROM Derived_Values;
go

select * from Derived_Values_Test;


BUSINESSUNIT    QUESTIONS   ANSWER
BU1 Q11 Updated Answers A11
BU1 Q12 Updated Answers A12
BU2 Q21 Updated Answers A21
BU2 Q22 Updated Answers A22

BUSINESSUNIT    QUESTIONS   ANSWER
BU1 Q11 Updated Answers A11
BU1 Q12 Updated Answers A12
BU2 Q21 Updated Answers A21
BU2 Q22 Updated Answers A22

Concatenating variables and strings in React

the best way to concat props/variables:

var sample = "test";    
var result = `this is just a ${sample}`;    
//this is just a test

Node.js Web Application examples/tutorials

Update

Dav Glass from Yahoo has given a talk at YuiConf2010 in November which is now available in Video from.

He shows to great extend how one can use YUI3 to render out widgets on the server side an make them work with GET requests when JS is disabled, or just make them work normally when it's active.

He also shows examples of how to use server side DOM to apply style sheets before rendering and other cool stuff.

The demos can be found on his GitHub Account.

The part that's missing IMO to make this really awesome, is some kind of underlying storage of the widget state. So that one can visit the page without JavaScript and everything works as expected, then they turn JS on and now the widget have the same state as before but work without page reloading, then throw in some saving to the server + WebSockets to sync between multiple open browser.... and the next generation of unobtrusive and gracefully degrading ARIA's is born.

Original Answer

Well go ahead and built it yourself then.

Seriously, 90% of all WebApps out there work fine with a REST approach, of course you could do magical things like superior user tracking, tracking of downloads in real time, checking which parts of videos are being watched etc.

One problem is scalability, as soon as you have more then 1 Node process, many (but not all) of the benefits of having the data stored between requests go away, so you have to make sure that clients always hit the same process. And even then, bigger things will yet again need a database layer.

Node.js isn't the solution to everything, I'm sure people will build really great stuff in the future, but that needs some time, right now many are just porting stuff over to Node to get things going.

What (IMHO) makes Node.js so great, is the fact that it streamlines the Development process, you have to write less code, it works perfectly with JSON, you loose all that context switching.

I mainly did gaming experiments so far, but I can for sure say that there will be many cool multi player (or even MMO) things in the future, that use both HTML5 and Node.js.

Node.js is still gaining traction, it's not even near to the RoR Hype some years ago (just take a look at the Node.js tag here on SO, hardly 4-5 questions a day).

Rome (or RoR) wasn't built over night, and neither will Node.js be.

Node.js has all the potential it needs, but people are still trying things out, so I'd suggest you to join them :)

How to programmatically send a 404 response with Express/Node?

You don't have to simulate it. The second argument to res.send I believe is the status code. Just pass 404 to that argument.

Let me clarify that: Per the documentation on expressjs.org it seems as though any number passed to res.send() will be interpreted as the status code. So technically you could get away with:

res.send(404);

Edit: My bad, I meant res instead of req. It should be called on the response

Edit: As of Express 4, the send(status) method has been deprecated. If you're using Express 4 or later, use: res.sendStatus(404) instead. (Thanks @badcc for the tip in the comments)

How to get host name with port from a http or https request

You can use HttpServletRequest.getScheme() to retrieve either "http" or "https".

Using it along with HttpServletRequest.getServerName() should be enough to rebuild the portion of the URL you need.

You don't need to explicitly put the port in the URL if you're using the standard ones (80 for http and 443 for https).

Edit: If your servlet container is behind a reverse proxy or load balancer that terminates the SSL, it's a bit trickier because the requests are forwarded to the servlet container as plain http. You have a few options:

1) Use HttpServletRequest.getHeader("x-forwarded-proto") instead; this only works if your load balancer sets the header correctly (Apache should afaik).

2) Configure a RemoteIpValve in JBoss/Tomcat that will make getScheme() work as expected. Again, this will only work if the load balancer sets the correct headers.

3) If the above don't work, you could configure two different connectors in Tomcat/JBoss, one for http and one for https, as described in this article.

Indirectly referenced from required .class file

This issue happen because of few jars are getting references from other jar and reference jar is missing .

Example : Spring framework

Description Resource    Path    Location    Type
The project was not built since its build path is incomplete. Cannot find the class file for org.springframework.beans.factory.annotation.Autowire. Fix the build path then try building this project   SpringBatch     Unknown Java Problem

In this case "org.springframework.beans.factory.annotation.Autowire" is missing.

Spring-bean.jar is missing

Once you add dependency in your class path issue will resolve.

DTO and DAO concepts and MVC

DTO is an abbreviation for Data Transfer Object, so it is used to transfer the data between classes and modules of your application.

DTO should only contain private fields for your data, getters, setters, and constructors.
DTO is not recommended to add business logic methods to such classes, but it is OK to add some util methods.

DAO is an abbreviation for Data Access Object, so it should encapsulate the logic for retrieving, saving and updating data in your data storage (a database, a file-system, whatever).

Here is an example of how the DAO and DTO interfaces would look like:

interface PersonDTO {
    String getName();
    void setName(String name);
    //.....
}

interface PersonDAO {
    PersonDTO findById(long id);
    void save(PersonDTO person);
    //.....
}

The MVC is a wider pattern. The DTO/DAO would be your model in the MVC pattern.
It tells you how to organize the whole application, not just the part responsible for data retrieval.

As for the second question, if you have a small application it is completely OK, however, if you want to follow the MVC pattern it would be better to have a separate controller, which would contain the business logic for your frame in a separate class and dispatch messages to this controller from the event handlers.
This would separate your business logic from the view.

Why does Node.js' fs.readFile() return a buffer instead of string?

Try:

    fs.readFile("test.txt", "utf8", function(err, data) {...});

Basically, you need to specify the encoding.

How to get array keys in Javascript?

The stringified keys can be queried with Object.keys(array).

Using client certificate in Curl command

TLS client certificates are not sent in HTTP headers. They are transmitted by the client as part of the TLS handshake, and the server will typically check the validity of the certificate during the handshake as well.

If the certificate is accepted, most web servers can be configured to add headers for transmitting the certificate or information contained on the certificate to the application. Environment variables are populated with certificate information in Apache and Nginx which can be used in other directives for setting headers.

As an example of this approach, the following Nginx config snippet will validate a client certificate, and then set the SSL_CLIENT_CERT header to pass the entire certificate to the application. This will only be set when then certificate was successfully validated, so the application can then parse the certificate and rely on the information it bears.

server {
    listen 443 ssl;
    server_name example.com;
    ssl_certificate /path/to/chainedcert.pem;  # server certificate
    ssl_certificate_key /path/to/key;          # server key

    ssl_client_certificate /path/to/ca.pem;    # client CA
    ssl_verify_client on;
    proxy_set_header SSL_CLIENT_CERT $ssl_client_cert;

    location / {
        proxy_pass http://localhost:3000;
    }
}

More elegant way of declaring multiple variables at the same time

When people are suggesting "use a list or tuple or other data structure", what they're saying is that, when you have a lot of different values that you care about, naming them all separately as local variables may not be the best way to do things.

Instead, you may want to gather them together into a larger data structure that can be stored in a single local variable.

intuited showed how you might use a dictionary for this, and Chris Lutz showed how to use a tuple for temporary storage before unpacking into separate variables, but another option to consider is to use collections.namedtuple to bundle the values more permanently.

So you might do something like:

# Define the attributes of our named tuple
from collections import namedtuple
DataHolder = namedtuple("DataHolder", "a b c d e f g")

# Store our data
data = DataHolder(True, True, True, True, True, False, True)

# Retrieve our data
print(data)
print(data.a, data.f)

Real code would hopefully use more meaningful names than "DataHolder" and the letters of the alphabet, of course.

What does double question mark (??) operator mean in PHP

$myVar = $someVar ?? 42;

Is equivalent to :

$myVar = isset($someVar) ? $someVar : 42;

For constants, the behaviour is the same when using a constant that already exists :

define("FOO", "bar");
define("BAR", null);

$MyVar = FOO ?? "42";
$MyVar2 = BAR ?? "42";

echo $MyVar . PHP_EOL;  // bar
echo $MyVar2 . PHP_EOL; // 42

However, for constants that don't exist, this is different :

$MyVar3 = IDONTEXIST ?? "42"; // Raises a warning
echo $MyVar3 . PHP_EOL;       // IDONTEXIST

Warning: Use of undefined constant IDONTEXIST - assumed 'IDONTEXIST' (this will throw an Error in a future version of PHP)

Php will convert the non-existing constant to a string.

You can use constant("ConstantName") that returns the value of the constant or null if the constant doesn't exist, but it will still raise a warning. You can prepended the function with the error control operator @ to ignore the warning message :

$myVar = @constant("IDONTEXIST") ?? "42"; // No warning displayed anymore
echo $myVar . PHP_EOL; // 42

How read Doc or Docx file in java?

Here is the code of ReadDoc/docx.java: This will read a dox/docx file and print its content to the console. you can customize it your way.

import java.io.*;
import org.apache.poi.hwpf.HWPFDocument;
import org.apache.poi.hwpf.extractor.WordExtractor;

public class ReadDocFile
{
    public static void main(String[] args)
    {
        File file = null;
        WordExtractor extractor = null;
        try
        {

            file = new File("c:\\New.doc");
            FileInputStream fis = new FileInputStream(file.getAbsolutePath());
            HWPFDocument document = new HWPFDocument(fis);
            extractor = new WordExtractor(document);
            String[] fileData = extractor.getParagraphText();
            for (int i = 0; i < fileData.length; i++)
            {
                if (fileData[i] != null)
                    System.out.println(fileData[i]);
            }
        }
        catch (Exception exep)
        {
            exep.printStackTrace();
        }
    }
}

How to change the type of a field?

You can easily convert the string data type to numerical data type.
Don't forget to change collectionName & FieldName.
for ex : CollectionNmae : Users & FieldName : Contactno.

Try this query..

db.collectionName.find().forEach( function (x) {
x.FieldName = parseInt(x.FieldName);
db.collectionName.save(x);
});

How to avoid "Permission denied" when using pip with virtualenv

You did not activate the virtual environment before using pip.

Try it with:

$(your venv path) . bin/activate

And then use pip -r requirements.txt on your main folder

DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss") is returning AM time instead of PM time?

With C#6.0 you also have a new way of formatting date when using string interpolation e.g.

$"{DateTime.Now:yyyy-MM-dd HH:mm:ss}"

Can't say its any better, but it is slightly cleaner if including the formatted DateTime in a longer string.

More about string interpolation.

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

Bart Kiers, your regex has a couple issues. The best way to do that is this:

(.*[a-z].*)       // For lower cases
(.*[A-Z].*)       // For upper cases
(.*\d.*)          // For digits

In this way you are searching no matter if at the beginning, at the end or at the middle. In your have I have a lot of troubles with complex passwords.

Why use String.Format?

String.Format adds many options in addition to the concatenation operators, including the ability to specify the specific format of each item added into the string.

For details on what is possible, I'd recommend reading the section on MSDN titled Composite Formatting. It explains the advantage of String.Format (as well as xxx.WriteLine and other methods that support composite formatting) over normal concatenation operators.

Compiler error: memset was not declared in this scope

Whevever you get a problem like this just go to the man page for the function in question and it will tell you what header you are missing, e.g.

$ man memset

MEMSET(3)                BSD Library Functions Manual                MEMSET(3)

NAME
     memset -- fill a byte string with a byte value

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <string.h>

     void *
     memset(void *b, int c, size_t len);

Note that for C++ it's generally preferable to use the proper equivalent C++ headers, <cstring>/<cstdio>/<cstdlib>/etc, rather than C's <string.h>/<stdio.h>/<stdlib.h>/etc.

Iterate through Nested JavaScript Objects

var findObjectByLabel = function(obj, label) 
{
  var foundLabel=null;
  if(obj.label === label)
  { 
    return obj; 
  }

for(var i in obj) 
{
    if(Array.isArray(obj[i])==true)
    {
        for(var j=0;j<obj[i].length;j++)
        {
            foundLabel = findObjectByLabel(obj[i], label);
        }
    }
    else if(typeof(obj[i])  == 'object')
    {
        if(obj.hasOwnProperty(i))
        {           
            foundLabel = findObjectByLabel(obj[i], label);     
        }       
    }

    if(foundLabel) 
    { 
        return foundLabel; 
    }

}

return null;
};

var x = findObjectByLabel(cars, "Sedan");
alert(JSON.stringify(x));

Clean up a fork and restart it from the upstream

How to do it 100% through the Sourcetree GUI

(Not everyone likes doing things through the git command line interface)

Once this has been set up, you only need to do steps 7-13 from then on.

Fetch > checkout master branch > reset to their master > Push changes to server

Steps

In the menu toolbar at the top of the screen: "Repository" > "Repository settings"

"Add"

Go back to GitHub and copy the clone URL.

Paste the url into the "URL / Path" field then give it a name that makes sense. I called it "master". Do not check the "Default remote" checkbox. You will not be able to push directly to this repository.

Press "OK" and you should see it appear in your list of repositories now.

Press "OK" again and you should see it appear in your list of "Remotes".

Click the "Fetch" button (top left of the Source tree header area)

Make sure the "Fetch from all remotes" checkbox is checked and press "ok"

Double click on your "master" branch to check it out if it is not checked out already.
Find the commit that you want to reset to, if you called the repo "master" you will most likely want to find the commit with the "master/master" tag on it.

Right click on the commit > "Reset current branch to this commit".
In the dialog, set the "Using mode:" field to "Hard - discard all working copy changes" then press "OK" (make sure to put any changes that you don't want to lose onto a separate branch first).

Click the "Push" button (top left of the Source tree header area) to upload the changes to your copy of the repo.

Your Done!

How to uncompress a tar.gz in another directory

gzip -dc archive.tar.gz | tar -xf - -C /destination

or, with GNU tar

tar xzf archive.tar.gz -C /destination

Spring data JPA query with parameter properties

Define the query method with signatures as follows.

@Query(select p from Person p where p.forename = :forename and p.surname = :surname)
User findByForenameAndSurname(@Param("surname") String lastname,
                             @Param("forename") String firstname);
}

For further details, check the Spring Data JPA reference

How to convert List<Integer> to int[] in Java?

No one mentioned yet streams added in Java 8 so here it goes:

int[] array = list.stream().mapToInt(i->i).toArray();
//OR
//int[] array = list.stream().mapToInt(Integer::intValue).toArray();

Thought process:

simple Stream#toArray returns Object[], so it is not what we want. Also Stream#toArray(IntFunction<A[]> generator) doesn't do what we want because generic type A can't represent primitive int
so it would be nice to have some stream which could handle primitive type int instead of wrapper Integer, because its toArray method will most likely also return int[] array (returning something else like Object[] or even boxed Integer[] would be unnatural here). And fortunately Java 8 has such stream which is IntStream
so now only thing we need to figure out is how to convert our Stream<Integer> (which will be returned from list.stream()) to that shiny IntStream. Here Stream#mapToInt(ToIntFunction<? super T> mapper) method comes to a rescue. All we need to do is pass to it mapping from Integer to int. We could use something like Integer#intValue which returns int like :
```
  mapToInt( (Integer i) -> i.intValue() )  
```

(or if someone prefers mapToInt(Integer::intValue) )

but similar code can be generated using unboxing, since compiler knows that result of this lambda must be int (lambda in mapToInt is implementation of ToIntFunction interface which expects body for int applyAsInt(T value) method which is expected to return int).

So we can simply write

    mapToInt((Integer i)->i)

Also since Integer type in (Integer i) can be inferred by compiler because List<Integer>#stream() returns Stream<Integer> we can also skip it which leaves us with

    mapToInt(i -> i)

How do I change the default library path for R packages

After a couple of hours of trying to solve the issue in several ways, some of which are described here, for me (on Win 10) the option of creating a Renviron file worked, but a little different from what was written here above. The task is to change the value of the variable R_LIBS_USER. To do this two steps needed:

Create the file named Renviron (without dot) in the folder \Program\etc\ (Programm is the directory where the R installed, for example for me it was c:\Program Files\R\R-4.0.0\etc)
Insert a line in Renviron with new path: R_LIBS_USER=c:/R/Library

It's been working for a few days already.

Why does ENOENT mean "No such file or directory"?

It's simply “No such directory entry”. Since directory entries can be directories or files (or symlinks, or sockets, or pipes, or devices), the name ENOFILE would have been too narrow in its meaning.

How do I preserve line breaks when getting text from a textarea?

The target container should have the white-space:pre style. Try it below.

_x000D_

<script>_x000D_
function copycontent(){_x000D_
 var content = document.getElementById('ta').value;_x000D_
 document.getElementById('target').innerText = content;_x000D_
}_x000D_
</script>_x000D_
<textarea id='ta' rows='3'>_x000D_
  line 1_x000D_
  line 2_x000D_
  line 3_x000D_
</textarea>_x000D_
<button id='btn' onclick='copycontent();'>_x000D_
Copy_x000D_
</button>_x000D_
<p id='target' style='white-space:pre'>_x000D_
_x000D_
</p>

_x000D_

How to make the script wait/sleep in a simple way in unity

With .Net 4.x you can use Task-based Asynchronous Pattern (TAP) to achieve this:

// .NET 4.x async-await
using UnityEngine;
using System.Threading.Tasks;
public class AsyncAwaitExample : MonoBehaviour
{
     private async void Start()
     {
        Debug.Log("Wait.");
        await WaitOneSecondAsync();
        DoMoreStuff(); // Will not execute until WaitOneSecond has completed
     }
    private async Task WaitOneSecondAsync()
    {
        await Task.Delay(TimeSpan.FromSeconds(1));
        Debug.Log("Finished waiting.");
    }
}

this is a feature to use .Net 4.x with Unity please see this link for description about it

and this link for sample project and compare it with coroutine

But becareful as documentation says that This is not fully replacement with coroutine

How to get the innerHTML of selectable jquery element?

$(function() {
        $("#select-image").selectable({
            selected: function( event, ui ) { 
                var $variable = $('.ui-selected').html(); 
                console.log($variable);
            }
        });
    });

$(function() {
        $("#select-image").selectable({
            selected: function( event, ui ) { 
                var $variable = $('.ui-selected').text(); 
                console.log($variable);
            }
        });
    });

$(function() {
        $("#select-image").selectable({
            selected: function( event, ui ) { 
                var $variable = $('.ui-selected').val(); 
                console.log($variable);
            }
        });
    });

How do I set the visibility of a text box in SSRS using an expression?

Visibility of the text box depends on the Hidden Value

As per the below example, if the internal condition satisfies then text box Hidden functionality will be True else if the condition fails then text box Hidden functionality will be False

=IIf((CountRows("ScannerStatisticsData") = 0), True, False)

How to "wait" a Thread in Android

You need the sleep method of the Thread class.

public static void sleep (long time)

Causes the thread which sent this message to sleep for the given interval of time (given in milliseconds). The precision is not guaranteed - the Thread may sleep more or less than requested.

Parameters

time The time to sleep in milliseconds.

How do you use global variables or constant values in Ruby?

Variable scope in Ruby is controlled by sigils to some degree. Variables starting with $ are global, variables with @ are instance variables, @@ means class variables, and names starting with a capital letter are constants. All other variables are locals. When you open a class or method, that's a new scope, and locals available in the previous scope aren't available.

I generally prefer to avoid creating global variables. There are two techniques that generally achieve the same purpose that I consider cleaner:

Create a constant in a module. So in this case, you would put all the classes that need the offset in the module Foo and create a constant Offset, so then all the classes could access Foo::Offset.
Define a method to access the value. You can define the method globally, but again, I think it's better to encapsulate it in a module or class. This way the data is available where you need it and you can even alter it if you need to, but the structure of your program and the ownership of the data will be clearer. This is more in line with OO design principles.

Execute an action when an item on the combobox is selected

this is how you do it with ActionLIstener

import java.awt.FlowLayout;
import java.awt.event.*;

import javax.swing.*;

public class MyWind extends JFrame{

    public MyWind() {
        initialize();
    }

    private void initialize() {
        setSize(300, 300);
        setLayout(new FlowLayout(FlowLayout.LEFT));
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        final JTextField field = new JTextField();
        field.setSize(200, 50);
        field.setText("              ");

        JComboBox comboBox = new JComboBox();
        comboBox.setEditable(true);
        comboBox.addItem("item1");
        comboBox.addItem("item2");

        //
        // Create an ActionListener for the JComboBox component.
        //
        comboBox.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                //
                // Get the source of the component, which is our combo
                // box.
                //
                JComboBox comboBox = (JComboBox) event.getSource();

                Object selected = comboBox.getSelectedItem();
                if(selected.toString().equals("item1"))
                field.setText("30");
                else if(selected.toString().equals("item2"))
                    field.setText("40");

            }
        });
        getContentPane().add(comboBox);
        getContentPane().add(field);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new MyWind().setVisible(true);
            }
        });
    }
}

java.sql.SQLException: Fail to convert to internal representation

Your data types are mismatched when you are retrieving the field values.

Also check how you store your enums, default is ORDINAL (numeric value stored in database), but STRING (name of enum stored in database) is also an option. Make sure the Entity in your code and the Model in your database are exactly the same.

I had an enum mismatch. It was set to default (ORDINAL) but the database model was expecting a string VARCHAR2(100char). Solution: @Enumerated(EnumType.STRING)

jsonify a SQLAlchemy result set in Flask

I just want to add my method to do this.

just define a custome json encoder to serilize your db models.

class ParentEncoder(json.JSONEncoder):
    def default(self, obj):
        # convert object to a dict
        d = {}
        if isinstance(obj, Parent):
            return {"id": obj.id, "name": obj.name, 'children': list(obj.child)}
        if isinstance(obj, Child):
            return {"id": obj.id, "name": obj.name}

        d.update(obj.__dict__)
        return d

then in your view function

parents = Parent.query.all()
dat = json.dumps({"data": parents}, cls=ParentEncoder)
resp = Response(response=dat, status=200, mimetype="application/json")
return (resp)

it works well though the parent have relationships

Display rows with one or more NaN values in pandas dataframe

You can use DataFrame.any with parameter axis=1 for check at least one True in row by DataFrame.isna with boolean indexing:

df1 = df[df.isna().any(axis=1)]

d = {'filename': ['M66_MI_NSRh35d32kpoints.dat', 'F71_sMI_DMRI51d.dat', 'F62_sMI_St22d7.dat', 'F41_Car_HOC498d.dat', 'F78_MI_547d.dat'], 'alpha1': [0.8016, 0.0, 1.721, 1.167, 1.897], 'alpha2': [0.9283, 0.0, 3.833, 2.809, 5.459], 'gamma1': [1.0, np.nan, 0.23748000000000002, 0.36419, 0.095319], 'gamma2': [0.074804, 0.0, 0.15, 0.3, np.nan], 'chi2min': [39.855990000000006, 1e+25, 10.91832, 7.966335000000001, 25.93468]}
df = pd.DataFrame(d).set_index('filename')

print (df)
                             alpha1  alpha2    gamma1    gamma2       chi2min
filename                                                                     
M66_MI_NSRh35d32kpoints.dat  0.8016  0.9283  1.000000  0.074804  3.985599e+01
F71_sMI_DMRI51d.dat          0.0000  0.0000       NaN  0.000000  1.000000e+25
F62_sMI_St22d7.dat           1.7210  3.8330  0.237480  0.150000  1.091832e+01
F41_Car_HOC498d.dat          1.1670  2.8090  0.364190  0.300000  7.966335e+00
F78_MI_547d.dat              1.8970  5.4590  0.095319       NaN  2.593468e+01

Explanation:

print (df.isna())
                            alpha1 alpha2 gamma1 gamma2 chi2min
filename                                                       
M66_MI_NSRh35d32kpoints.dat  False  False  False  False   False
F71_sMI_DMRI51d.dat          False  False   True  False   False
F62_sMI_St22d7.dat           False  False  False  False   False
F41_Car_HOC498d.dat          False  False  False  False   False
F78_MI_547d.dat              False  False  False   True   False

print (df.isna().any(axis=1))
filename
M66_MI_NSRh35d32kpoints.dat    False
F71_sMI_DMRI51d.dat             True
F62_sMI_St22d7.dat             False
F41_Car_HOC498d.dat            False
F78_MI_547d.dat                 True
dtype: bool

df1 = df[df.isna().any(axis=1)]
print (df1)
                     alpha1  alpha2    gamma1  gamma2       chi2min
filename                                                           
F71_sMI_DMRI51d.dat   0.000   0.000       NaN     0.0  1.000000e+25
F78_MI_547d.dat       1.897   5.459  0.095319     NaN  2.593468e+01

How to create a thread?

public class ThreadParameter
        {
            public int Port { get; set; }
            public string Path { get; set; }
        }


Thread t = new Thread(new ParameterizedThreadStart(Startup));
t.Start(new ThreadParameter() { Port = port, Path = path});

Create an object with the port and path objects and pass it to the Startup method.

Django request.GET

Calling /search/ should result in "you submitted nothing", but calling /search/?q= on the other hand should result in "you submitted u''"

Browsers have to add the q= even when it's empty, because they have to include all fields which are part of the form. Only if you do some DOM manipulation in Javascript (or a custom javascript submit action), you might get such a behavior, but only if the user has javascript enabled. So you should probably simply test for non-empty strings, e.g:

if request.GET.get('q'):
    message = 'You submitted: %r' % request.GET['q']
else:
    message = 'You submitted nothing!'

How to access Winform textbox control from another class?

You will need to have some access to the Form's Instance to access its Controls collection and thereby changing the Text Box's Text.

One of ways could be that You can have a Your Form's Instance Available as Public or More better Create a new Constructor For your Second Form and have it receive the Form1's instance during initialization.

Easiest way to toggle 2 classes in jQuery

Here's another 'non-conventional' way.

It implies the use of underscore or lodash.
It assumes a context where you:
- the element doesn't have an init class (that means you cannot do toggleClass('a b'))
- you have to get the class dynamically from somewhere

An example of this scenario could be buttons that has the class to be switched on another element (say tabs in a container).

// 1: define the array of switching classes:
var types = ['web','email'];

// 2: get the active class:
var type = $(mybutton).prop('class');

// 3: switch the class with the other on (say..) the container. You can guess the other by using _.without() on the array:
$mycontainer.removeClass(_.without(types, type)[0]).addClass(type);

Are HTTP headers case-sensitive?

officially, headers are case insensitive, however, it is common practice to capitalize the first letter of every word.
but, because it is common practice, certain programs like IE assume the headers are capitalized.
so while the docs say the are case insensitive, bad programmers have basically changed the docs.

Do you have to put Task.Run in a method to make it async?

First, let's clear up some terminology: "asynchronous" (async) means that it may yield control back to the calling thread before it starts. In an async method, those "yield" points are await expressions.

This is very different than the term "asynchronous", as (mis)used by the MSDN documentation for years to mean "executes on a background thread".

To futher confuse the issue, async is very different than "awaitable"; there are some async methods whose return types are not awaitable, and many methods returning awaitable types that are not async.

Enough about what they aren't; here's what they are:

The async keyword allows an asynchronous method (that is, it allows await expressions). async methods may return Task, Task<T>, or (if you must) void.
Any type that follows a certain pattern can be awaitable. The most common awaitable types are Task and Task<T>.

So, if we reformulate your question to "how can I run an operation on a background thread in a way that it's awaitable", the answer is to use Task.Run:

private Task<int> DoWorkAsync() // No async because the method does not need await
{
  return Task.Run(() =>
  {
    return 1 + 2;
  });
}

(But this pattern is a poor approach; see below).

But if your question is "how do I create an async method that can yield back to its caller instead of blocking", the answer is to declare the method async and use await for its "yielding" points:

private async Task<int> GetWebPageHtmlSizeAsync()
{
  var client = new HttpClient();
  var html = await client.GetAsync("http://www.example.com/");
  return html.Length;
}

So, the basic pattern of things is to have async code depend on "awaitables" in its await expressions. These "awaitables" can be other async methods or just regular methods returning awaitables. Regular methods returning Task/Task<T> can use Task.Run to execute code on a background thread, or (more commonly) they can use TaskCompletionSource<T> or one of its shortcuts (TaskFactory.FromAsync, Task.FromResult, etc). I don't recommend wrapping an entire method in Task.Run; synchronous methods should have synchronous signatures, and it should be left up to the consumer whether it should be wrapped in a Task.Run:

private int DoWork()
{
  return 1 + 2;
}

private void MoreSynchronousProcessing()
{
  // Execute it directly (synchronously), since we are also a synchronous method.
  var result = DoWork();
  ...
}

private async Task DoVariousThingsFromTheUIThreadAsync()
{
  // I have a bunch of async work to do, and I am executed on the UI thread.
  var result = await Task.Run(() => DoWork());
  ...
}

I have an async/await intro on my blog; at the end are some good followup resources. The MSDN docs for async are unusually good, too.

OpenSSL Verify return code: 20 (unable to get local issuer certificate)

Solution: You must explicitly add the parameter -CAfile your-ca-file.pem.

Note: I tried also param -CApath mentioned in another answers, but is does not works for me.

Explanation: Error unable to get local issuer certificate means, that the openssl does not know your root CA cert.

Note: If you have web server with more domains, do not forget to add also -servername your.domain.net parameter. This parameter will "Set TLS extension servername in ClientHello". Without this parameter, the response will always contain the default SSL cert (not certificate, that match to your domain).

When should I use File.separator and when File.pathSeparator?

You use separator when you are building a file path. So in unix the separator is /. So if you wanted to build the unix path /var/temp you would do it like this:

String path = File.separator + "var"+ File.separator + "temp"

You use the pathSeparator when you are dealing with a list of files like in a classpath. For example, if your app took a list of jars as argument the standard way to format that list on unix is: /path/to/jar1.jar:/path/to/jar2.jar:/path/to/jar3.jar

So given a list of files you would do something like this:

String listOfFiles = ...
String[] filePaths = listOfFiles.split(File.pathSeparator);

How to determine if a string is a number with C++?

C/C++ style for unsigned integers, using range based for C++11:

int isdigits(const std::string & s)
{
    for (char c : s) if (!isdigit(c)) return (0);
    return (1);
}

Convert string into Date type on Python

Use datetime.datetime.strptime:

>>> import datetime
>>> date = datetime.datetime.strptime('2012-02-10', '%Y-%m-%d')
>>> date.isoweekday()
5

How do I get the file extension of a file in Java?

I like the simplicity of spectre's answer, and linked in one of his comments is a link to another answer that fixes dots in file paths, on another question, made by EboMike.

Without implementing some sort of third party API, I suggest:

private String getFileExtension(File file) {

    String name = file.getName().substring(Math.max(file.getName().lastIndexOf('/'),
            file.getName().lastIndexOf('\\')) < 0 ? 0 : Math.max(file.getName().lastIndexOf('/'),
            file.getName().lastIndexOf('\\')));
    int lastIndexOf = name.lastIndexOf(".");
    if (lastIndexOf == -1) {
        return ""; // empty extension
    }
    return name.substring(lastIndexOf + 1); // doesn't return "." with extension
}

Something like this may be useful in, say, any of ImageIO's write methods, where the file format has to be passed in.

Why use a whole third party API when you can DIY?

How to error handle 1004 Error with WorksheetFunction.VLookup?

Instead of WorksheetFunction.Vlookup, you can use Application.Vlookup. If you set a Variant equal to this it returns Error 2042 if no match is found. You can then test the variant - cellNum in this case - with IsError:

Sub test()
Dim ws As Worksheet: Set ws = Sheets("2012")
Dim rngLook As Range: Set rngLook = ws.Range("A:M")
Dim currName As String
Dim cellNum As Variant

'within a loop
currName = "Example"
cellNum = Application.VLookup(currName, rngLook, 13, False)
If IsError(cellNum) Then
    MsgBox "no match"
Else
    MsgBox cellNum
End If
End Sub

The Application versions of the VLOOKUP and MATCH functions allow you to test for errors without raising the error. If you use the WorksheetFunction version, you need convoluted error handling that re-routes your code to an error handler, returns to the next statement to evaluate, etc. With the Application functions, you can avoid that mess.

The above could be further simplified using the IIF function. This method is not always appropriate (e.g., if you have to do more/different procedure based on the If/Then) but in the case of this where you are simply trying to determinie what prompt to display in the MsgBox, it should work:

cellNum = Application.VLookup(currName, rngLook, 13, False)
MsgBox IIF(IsError(cellNum),"no match", cellNum)

Consider those methods instead of On Error ... statements. They are both easier to read and maintain -- few things are more confusing than trying to follow a bunch of GoTo and Resume statements.

Groovy / grails how to determine a data type?

Just to add another option to Dónal's answer, you can also still use the good old java.lang.Object.getClass() method.

Search for one value in any column of any table inside a database

I expanded the code, because it's not told me the 'record number', and I must to refind it.

CREATE PROC SearchAllTables
(
@SearchStr nvarchar(100)
)
AS
BEGIN

-- Copyright © 2002 Narayana Vyas Kondreddi. All rights reserved.
-- Purpose: To search all columns of all tables for a given search string
-- Written by: Narayana Vyas Kondreddi
-- Site: http://vyaskn.tripod.com
-- Tested on: SQL Server 7.0 and SQL Server 2000
-- Date modified: 28th July 2002 22:50 GMT

-- Copyright @ 2012 Gyula Kulifai. All rights reserved.
-- Extended By: Gyula Kulifai
-- Purpose: To put key values, to exactly determine the position of search
-- Resources: Anatoly Lubarsky
-- Date extension: 19th October 2012 12:24 GMT
-- Tested on: SQL Server 10.0.5500 (SQL Server 2008 SP3)

CREATE TABLE #Results (TableName nvarchar(370), KeyValues nvarchar(3630), ColumnName nvarchar(370), ColumnValue nvarchar(3630))

SET NOCOUNT ON

DECLARE @TableName nvarchar(256), @ColumnName nvarchar(128), @SearchStr2 nvarchar(110)
    ,@TableShortName nvarchar(256)
    ,@TableKeys nvarchar(512)
    ,@SQL nvarchar(3830)

SET  @TableName = ''
SET @SearchStr2 = QUOTENAME('%' + @SearchStr + '%','''')

WHILE @TableName IS NOT NULL
BEGIN
    SET @ColumnName = ''

    -- Scan Tables
    SET @TableName = 
    (
        SELECT MIN(QUOTENAME(TABLE_SCHEMA) + '.' + QUOTENAME(TABLE_NAME))
        FROM    INFORMATION_SCHEMA.TABLES
        WHERE       TABLE_TYPE = 'BASE TABLE'
            AND QUOTENAME(TABLE_SCHEMA) + '.' + QUOTENAME(TABLE_NAME) > @TableName
            AND OBJECTPROPERTY(
                    OBJECT_ID(
                        QUOTENAME(TABLE_SCHEMA) + '.' + QUOTENAME(TABLE_NAME)
                         ), 'IsMSShipped'
                           ) = 0
    )
    Set @TableShortName=PARSENAME(@TableName, 1)
    -- print @TableName + ';' + @TableShortName +'!' -- *** DEBUG LINE ***

        -- LOOK Key Fields, Set Key Columns
        SET @TableKeys=''
        SELECT @TableKeys = @TableKeys + '''' + QUOTENAME([name]) + ': '' + CONVERT(nvarchar(250),' + [name] + ') + ''' + ',' + ''' + '
         FROM syscolumns 
         WHERE [id] IN (
            SELECT [id] 
             FROM sysobjects 
             WHERE [name] = @TableShortName)
           AND colid IN (
            SELECT SIK.colid 
             FROM sysindexkeys SIK 
             JOIN sysobjects SO ON 
                SIK.[id] = SO.[id]  
             WHERE 
                SIK.indid = 1
                AND SO.[name] = @TableShortName)
        If @TableKeys<>''
            SET @TableKeys=SUBSTRING(@TableKeys,1,Len(@TableKeys)-8)
        -- Print @TableName + ';' + @TableKeys + '!' -- *** DEBUG LINE ***

    -- Search in Columns
    WHILE (@TableName IS NOT NULL) AND (@ColumnName IS NOT NULL)
    BEGIN
        SET @ColumnName =
        (
            SELECT MIN(QUOTENAME(COLUMN_NAME))
            FROM    INFORMATION_SCHEMA.COLUMNS
            WHERE       TABLE_SCHEMA    = PARSENAME(@TableName, 2)
                AND TABLE_NAME  = PARSENAME(@TableName, 1)
                AND DATA_TYPE IN ('char', 'varchar', 'nchar', 'nvarchar')
                AND QUOTENAME(COLUMN_NAME) > @ColumnName
        ) -- Set ColumnName

        IF @ColumnName IS NOT NULL
        BEGIN
            SET @SQL='
                SELECT 
                    ''' + @TableName + '''
                    ,'+@TableKeys+'
                    ,''' + @ColumnName + '''
                ,LEFT(' + @ColumnName + ', 3630) 
                FROM ' + @TableName + ' (NOLOCK) ' +
                ' WHERE ' + @ColumnName + ' LIKE ' + @SearchStr2
            --Print @SQL -- *** DEBUG LINE ***
            INSERT INTO #Results
                Exec (@SQL)
        END -- IF ColumnName
    END -- While Table and Column
END --While Table

SELECT TableName, KeyValues, ColumnName, ColumnValue FROM #Results
END

Angular 2: import external js file into component

Instead of including your js file extension in index.html, you can include it in .angular-cli-json file.

These are the steps I followed to get this working:

First include your external js file in assets/js
In .angular-cli.json - add the file path under scripts: [../app/assets/js/test.js]
In the component where you want to use the functions of the js file.

Declare at the top where you want to import the files as

declare const Test:any;

After this you can access its functions as for example Test.add()

Make UINavigationBar transparent

for Swift 3.0:

override func viewDidLoad() {
    super.viewDidLoad()

    navigationController?.navigationBar.setBackgroundImage(UIImage(), for: .default)
    navigationController?.navigationBar.shadowImage = UIImage()
    navigationController?.navigationBar.isTranslucent = true
}

How to start nginx via different port(other than 80)

If you are experiencing this problem when using Docker be sure to map the correct port numbers. If you map port 81:80 when running docker (or through docker-compose.yml), your nginx must listen on port 80 not 81, because docker does the mapping already.

I spent quite some time on this issue myself, so hope it can be to some help for future googlers.

What is LD_LIBRARY_PATH and how to use it?

Well, the error message tells you what to do: add the path where Jacob.dll resides to java.library.path. You can do that on the command line like this:

java -Djava.library.path="dlls" ...

(assuming Jacob.dll is in the "dlls" folder)

Also see java.lang.UnsatisfiedLinkError no *****.dll in java.library.path

Mockito: Inject real objects into private @Autowired fields

In Spring there is a dedicated utility called ReflectionTestUtils for this purpose. Take the specific instance and inject into the the field.


@Spy
..
@Mock
..

@InjectMock
Foo foo;

@BeforeEach
void _before(){
   ReflectionTestUtils.setField(foo,"bar", new BarImpl());// `bar` is private field
}

How do I modify the URL without reloading the page?

You can also use HTML5 replaceState if you want to change the url but don't want to add the entry to the browser history:

if (window.history.replaceState) {
   //prevents browser from storing history with each change:
   window.history.replaceState(statedata, title, url);
}

This would 'break' the back button functionality. This may be required in some instances such as an image gallery (where you want the back button to return back to the gallery index page instead of moving back through each and every image you viewed) whilst giving each image its own unique url.

XML shape drawable not rendering desired color

I had a similar problem and found that if you remove the size definition, it works for some reason.

Remove:

<size
    android:width="60dp"
    android:height="40dp" />

from the shape.

Let me know if this works!

PHP Constants Containing Arrays?

Since PHP 5.6, you can declare an array constant with const:

<?php
const DEFAULT_ROLES = array('guy', 'development team');

The short syntax works too, as you'd expect:

<?php
const DEFAULT_ROLES = ['guy', 'development team'];

If you have PHP 7, you can finally use define(), just as you had first tried:

<?php
define('DEFAULT_ROLES', array('guy', 'development team'));

How do I get the old value of a changed cell in Excel VBA?

Here's a way I've used in the past. Please note that you have to add a reference to the Microsoft Scripting Runtime so you can use the Dictionary object - if you don't want to add that reference you can do this with Collections but they're slower and there's no elegant way to check .Exists (you have to trap the error).

Dim OldVals As New Dictionary
Private Sub Worksheet_Change(ByVal Target As Range)
Dim cell As Range
    For Each cell In Target
        If OldVals.Exists(cell.Address) Then
            Debug.Print "New value of " & cell.Address & " is " & cell.Value & "; old value was " & OldVals(cell.Address)
        Else
            Debug.Print "No old value for " + cell.Address
        End If
        OldVals(cell.Address) = cell.Value
    Next
End Sub

Like any similar method, this has its problems - first off, it won't know the "old" value until the value has actually been changed. To fix this you'd need to trap the Open event on the workbook and go through Sheet.UsedRange populating OldVals. Also, it will lose all its data if you reset the VBA project by stopping the debugger or some such.

XMLHttpRequest cannot load an URL with jQuery

In new jQuery 1.5 you can use:

$.ajax({
    type: "GET",
    url: "http://localhost:99000/Services.svc/ReturnPersons",
    dataType: "jsonp",
    success: readData(data),
    error: function (xhr, ajaxOptions, thrownError) {
      alert(xhr.status);
      alert(thrownError);
    }
})

React Router with optional path parameter

for react-router V5 and above use below syntax for multiple paths

<Route
          exact
          path={[path1, path2]}
          component={component}
        />

Remove last commit from remote git repository

Be careful that this will create an "alternate reality" for people who have already fetch/pulled/cloned from the remote repository. But in fact, it's quite simple:

git reset HEAD^ # remove commit locally
git push origin +HEAD # force-push the new HEAD commit

If you want to still have it in your local repository and only remove it from the remote, then you can use:

git push origin +HEAD^:<name of your branch, most likely 'master'>

TINYTEXT, TEXT, MEDIUMTEXT, and LONGTEXT maximum storage sizes

Expansion of the same answer

This SO post outlines in detail the overheads and storage mechanisms.
As noted from point (1), A VARCHAR should always be used instead of TINYTEXT. However, when using VARCHAR, the max rowsize should not exceeed 65535 bytes.
As outlined here http://dev.mysql.com/doc/refman/5.0/en/charset-unicode-utf8.html, max 3 bytes for utf-8.

THIS IS A ROUGH ESTIMATION TABLE FOR QUICK DECISIONS!

So the worst case assumptions (3 bytes per utf-8 char) to best case (1 byte per utf-8 char)
Assuming the english language has an average of 4.5 letters per word
x is the number of bytes allocated

x-x

      Type | A= worst case (x/3) | B = best case (x) | words estimate (A/4.5) - (B/4.5)
-----------+---------------------------------------------------------------------------
  TINYTEXT |              85     | 255               | 18 - 56
      TEXT |          21,845     | 65,535            | 4,854.44 - 14,563.33  
MEDIUMTEXT |       5,592,415     | 16,777,215        | 1,242,758.8 - 3,728,270
  LONGTEXT |   1,431,655,765     | 4,294,967,295     | 318,145,725.5 - 954,437,176.6

Please refer to Chris V's answer as well : https://stackoverflow.com/a/35785869/1881812

Simplest way to detect a pinch

None of these answers achieved what I was looking for, so I wound up writing something myself. I wanted to pinch-zoom an image on my website using my MacBookPro trackpad. The following code (which requires jQuery) seems to work in Chrome and Edge, at least. Maybe this will be of use to someone else.

function setupImageEnlargement(el)
{
    // "el" represents the image element, such as the results of document.getElementByd('image-id')
    var img = $(el);
    $(window, 'html', 'body').bind('scroll touchmove mousewheel', function(e)
    {
        //TODO: need to limit this to when the mouse is over the image in question

        //TODO: behavior not the same in Safari and FF, but seems to work in Edge and Chrome

        if (typeof e.originalEvent != 'undefined' && e.originalEvent != null
            && e.originalEvent.wheelDelta != 'undefined' && e.originalEvent.wheelDelta != null)
        {
            e.preventDefault();
            e.stopPropagation();
            console.log(e);
            if (e.originalEvent.wheelDelta > 0)
            {
                // zooming
                var newW = 1.1 * parseFloat(img.width());
                var newH = 1.1 * parseFloat(img.height());
                if (newW < el.naturalWidth && newH < el.naturalHeight)
                {
                    // Go ahead and zoom the image
                    //console.log('zooming the image');
                    img.css(
                    {
                        "width": newW + 'px',
                        "height": newH + 'px',
                        "max-width": newW + 'px',
                        "max-height": newH + 'px'
                    });
                }
                else
                {
                    // Make image as big as it gets
                    //console.log('making it as big as it gets');
                    img.css(
                    {
                        "width": el.naturalWidth + 'px',
                        "height": el.naturalHeight + 'px',
                        "max-width": el.naturalWidth + 'px',
                        "max-height": el.naturalHeight + 'px'
                    });
                }
            }
            else if (e.originalEvent.wheelDelta < 0)
            {
                // shrinking
                var newW = 0.9 * parseFloat(img.width());
                var newH = 0.9 * parseFloat(img.height());

                //TODO: I had added these data-attributes to the image onload.
                // They represent the original width and height of the image on the screen.
                // If your image is normally 100% width, you may need to change these values on resize.
                var origW = parseFloat(img.attr('data-startwidth'));
                var origH = parseFloat(img.attr('data-startheight'));

                if (newW > origW && newH > origH)
                {
                    // Go ahead and shrink the image
                    //console.log('shrinking the image');
                    img.css(
                    {
                        "width": newW + 'px',
                        "height": newH + 'px',
                        "max-width": newW + 'px',
                        "max-height": newH + 'px'
                    });
                }
                else
                {
                    // Make image as small as it gets
                    //console.log('making it as small as it gets');
                    // This restores the image to its original size. You may want
                    //to do this differently, like by removing the css instead of defining it.
                    img.css(
                    {
                        "width": origW + 'px',
                        "height": origH + 'px',
                        "max-width": origW + 'px',
                        "max-height": origH + 'px'
                    });
                }
            }
        }
    });
}

Int or Number DataType for DataAnnotation validation attribute

You can write a custom validation attribute:

[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter, AllowMultiple = false)]
public class Numeric : ValidationAttribute
{
    public Numeric(string errorMessage) : base(errorMessage)
    {
    }

    /// <summary>
    /// Check if given value is numeric
    /// </summary>
    /// <param name="value">The input value</param>
    /// <returns>True if value is numeric</returns>
    public override bool IsValid(object value)
    {
        return decimal.TryParse(value?.ToString(), out _);
    }
}

On your property you can then use the following annotation:

[Numeric("Please fill in a valid number.")]
public int NumberOfBooks { get; set; }

Adding items to an object through the .push() method

Another way of doing it would be:

stuff = Object.assign(stuff, {$(this).attr('value'):$(this).attr('checked')});

How to install PyQt4 in anaconda?

For windows users, there is an easy fix. Download whl files from:

https://www.lfd.uci.edu/~gohlke/pythonlibs/#pyqt4

run from anaconda prompt pip install PyQt4-4.11.4-cp37-cp37m-win_amd64.whl

What does -z mean in Bash?

-z string True if the string is null (an empty string)

How do I include the string header?

Sources telling you to use apstring.h are materials for the Advanced Placement course in computer science. It describes a string class that you'll use through the course, and some of the exam questions may refer to it and expect you to be moderately familiar with it. Unless you're enrolled in that class or studying to take that exam, ignore those sources.

Sources telling you to use string.h are either not really talking about C++, or are severely outdated. You should probably ignore them, too. That header is for the C functions for manipulating null-terminated arrays of characters, also known as C-style strings.

In C++, you should use the string header. Write #include <string> at the top of your file. When you declare a variable, the type is string, and it's in the std namespace, so its full name is std::string. You can avoid having to write the namespace portion of that name all the time by following the example of lots of introductory texts and saying using namespace std at the top of the C++ source files (but generally not at the top of any header files you might write).

How may I sort a list alphabetically using jQuery?

HTML

<ul id="list">
    <li>alpha</li>
    <li>gamma</li>
    <li>beta</li>
</ul>

JavaScript

function sort(ul) {
    var ul = document.getElementById(ul)
    var liArr = ul.children
    var arr = new Array()
    for (var i = 0; i < liArr.length; i++) {
        arr.push(liArr[i].textContent)
    }
    arr.sort()
    arr.forEach(function(content, index) {
        liArr[index].textContent = content
    })
}

sort("list")

JSFiddle Demo https://jsfiddle.net/97oo61nw/

Here we are push all values of li elements inside ul with specific id (which we provided as function argument) to array arr and sort it using sort() method which is sorted alphabetical by default. After array arr is sorted we are loop this array using forEach() method and just replace text content of all li elements with sorted content

Set disable attribute based on a condition for Html.TextBoxFor

I like the extension method approach so you don't have to pass through all possible parameters.
However using Regular expressions can be quite tricky (and somewhat slower) so I used XDocument instead:

public static MvcHtmlString SetDisabled(this MvcHtmlString html, bool isDisabled)
{
    var xDocument = XDocument.Parse(html.ToHtmlString());
    if (!(xDocument.FirstNode is XElement element))
    {
        return html;
    }

    element.SetAttributeValue("disabled", isDisabled ? "disabled" : null);
    return MvcHtmlString.Create(element.ToString());
}

Use the extension method like this:
@Html.EditorFor(m => m.MyProperty).SetDisabled(Model.ExpireDate == null)

Facebook development in localhost

NOTE: As of 2012 Facebook allows registration of "localhost" as return Url. You still may need similar workaround for other providers (i.e. Microsoft one).

If you need real domain name registered with Facebook (like my.really.own.domain.com) you can locally redirect requests to this domain to your machine. Easiest out of box approach on any OS is to change "hosts" file to map the domain to 127.0.0.1 (see http://technet.microsoft.com/en-us/library/bb727005.aspx#EDAA and https://serverfault.com/questions/118290/cname-record-alias-in-windows-hosts-file).

I usually use Fiddler to do it for me (on Windows with local IIS) - see samples on http://www.fiddler2.com/Fiddler/Dev/ScriptSamples.asp.

if (oSession.HostnameIs("my.really.own.domain.com")) {
   oSession.host="localhost:80";
}

Hosts file approach of approaches does not work with Visual Studio Development Server as it requires incoming Urls to be localhost/127.0.0.1. If you need to work with it (or possibly with IIS express) to override host - Using Fiddler with IIS7 Express

Getting the class of the element that fired an event using JQuery

You will get all the class in below array

event.target.classList

Replace specific characters within strings

You do not need to create data frame from vector of strings, if you want to replace some characters in it. Regular expressions is good choice for it as it has been already mentioned by @Andrie and @Dirk Eddelbuettel.

Pay attention, if you want to replace special characters, like dots, you should employ full regular expression syntax, as shown in example below:

ctr_names <- c("Czech.Republic","New.Zealand","Great.Britain")
gsub("[.]", " ", ctr_names)

this will produce

[1] "Czech Republic" "New Zealand"    "Great Britain"

Best way to do a PHP switch with multiple values per case?

I definitely prefer Version 1. Version 2 may require less lines of code, but it will be extremely hard to read once you have a lot of values in there like you're predicting.

(Honestly, I didn't even know Version 2 was legal until now. I've never seen it done that way before.)

Using sed and grep/egrep to search and replace

try something using a for loop

 for i in `egrep -lR "YOURSEARCH" .` ; do echo  $i; sed 's/f/k/' <$i >/tmp/`basename $i`; mv /tmp/`basename $i` $i; done

not pretty, but should do.

How to clear all input fields in bootstrap modal when clicking data-dismiss button?

In addition to @Malk, I wanted to clear all fields in the popup, except the hidden fields. To do that just use this:

$('.modal').on('hidden.bs.modal', function () {
    $(this)
        .find("input:not([type=hidden]),textarea,select")
        .val('')
        .end()
        .find("input[type=checkbox], input[type=radio]")
        .prop("checked", "")
        .end();
});

This will clear all fields, except the hidden ones.

How to check if an Object is a Collection Type in Java?

Since you mentioned reflection in your question;

boolean isArray = myArray.getClass().isArray();
boolean isCollection = Collection.class.isAssignableFrom(myList.getClass());
boolean isMap = Map.class.isAssignableFrom(myMap.getClass());

Rounding BigDecimal to always have two decimal places

value = value.setScale(2, RoundingMode.CEILING)

Failed to build gem native extension — Rails install

sudo apt-get install ruby-dev

worked for me

Create stacked barplot where each stack is scaled to sum to 100%

Here's a solution using that ggplot package (version 3.x) in addition to what you've gotten so far.

We use the position argument of geom_bar set to position = "fill". You may also use position = position_fill() if you want to use the arguments of position_fill() (vjust and reverse).

Note that your data is in a 'wide' format, whereas ggplot2 requires it to be in a 'long' format. Thus, we first need to gather the data.

library(ggplot2)
library(dplyr)
library(tidyr)

dat <- read.table(text = "    ONE TWO THREE
1   23  234 324
2   34  534 12
3   56  324 124
4   34  234 124
5   123 534 654",sep = "",header = TRUE)

# Add an id variable for the filled regions and reshape
datm <- dat %>% 
  mutate(ind = factor(row_number())) %>%  
  gather(variable, value, -ind)

ggplot(datm, aes(x = variable, y = value, fill = ind)) + 
    geom_bar(position = "fill",stat = "identity") +
    # or:
    # geom_bar(position = position_fill(), stat = "identity") 
    scale_y_continuous(labels = scales::percent_format())

example figure

How to align a div to the top of its parent but keeping its inline-block behaviour?

Use vertical-align:top; for the element you want at the top, as I have demonstrated on your jsfiddle.

http://www.brunildo.org/test/inline-block.html

Up, Down, Left and Right arrow keys do not trigger KeyDown event

See Rodolfo Neuber's reply for the best answer

(My original answer):

Derive from a control class and you can override the ProcessCmdKey method. Microsoft chose to omit these keys from KeyDown events because they affect multiple controls and move the focus, but this makes it very difficult to make an app react to these keys in any other way.

I can't install python-ldap

To correct the error due to dependencies to install the python-ldap : Windows 7/10

download the whl file

http://www.lfd.uci.edu/~gohlke/pythonlibs/#python-ldap.

python 3.6 suit with

python_ldap-3.2.0-cp36-cp36m-win_amd64.whl

Deploy the file in :

c:\python36\Scripts\

install it with

python -m pip install python_ldap-3.2.0-cp36-cp36m-win_amd64.whl

Can I set a breakpoint on 'memory access' in GDB?

Use watch to see when a variable is written to, rwatch when it is read and awatch when it is read/written from/to, as noted above. However, please note that to use this command, you must break the program, and the variable must be in scope when you've broken the program:

Use the watch command. The argument to the watch command is an expression that is evaluated. This implies that the variabel you want to set a watchpoint on must be in the current scope. So, to set a watchpoint on a non-global variable, you must have set a breakpoint that will stop your program when the variable is in scope. You set the watchpoint after the program breaks.

How to install Jdk in centos

Here is something that might help. Use the root privileges. if you have .bin then simply add the execution permission to the bin file.

chmod a+x jdk*.bin

next step is to run the .bin file which is simply

./jdk*.bin in the location you want to install.

you are done.

Temporarily change current working directory in bash to run a command

bash has a builtin

pushd SOME_PATH
run_stuff
...
...
popd

Hibernate throws org.hibernate.AnnotationException: No identifier specified for entity: com..domain.idea.MAE_MFEView

This error was caused by importing the wrong Id class. After changing org.springframework.data.annotation.Id to javax.persistence.Id the application run

Run bash script from Windows PowerShell

You should put the script as argument for a *NIX shell you run, equivalent to the *NIXish

sh myscriptfile

Will iOS launch my app into the background if it was force-quit by the user?

You can change your target's launch settings in "Manage Scheme" to Wait for <app>.app to be launched manually, which allows you debug by setting a breakpoint in application: didReceiveRemoteNotification: fetchCompletionHandler: and sending the push notification to trigger the background launch.

I'm not sure it'll solve the issue, but it may assist you with debugging for now.

screenshot

How to get Client location using Google Maps API v3?

I couldn't get the above code to work.

Google does a great explanation though here: http://code.google.com/apis/maps/documentation/javascript/basics.html#DetectingUserLocation

Where they first use the W3C Geolocation method and then offer the Google.gears fallback method for older browsers.

The example is here:

http://code.google.com/apis/maps/documentation/javascript/examples/map-geolocation.html

how to emulate "insert ignore" and "on duplicate key update" (sql merge) with postgresql?

With PostgreSQL 9.5, this is now native functionality (like MySQL has had for several years):

INSERT ... ON CONFLICT DO NOTHING/UPDATE ("UPSERT")

9.5 brings support for "UPSERT" operations. INSERT is extended to accept an ON CONFLICT DO UPDATE/IGNORE clause. This clause specifies an alternative action to take in the event of a would-be duplicate violation.

...

Further example of new syntax:

INSERT INTO user_logins (username, logins)
VALUES ('Naomi',1),('James',1) 
ON CONFLICT (username)
DO UPDATE SET logins = user_logins.logins + EXCLUDED.logins;

Error: No Entity Framework provider found for the ADO.NET provider with invariant name 'System.Data.SqlClient'

Ok, this is pretty weird. I have a couple of projects: one is a UI project (an ASP.NET MVC project) and the others are projects for stuff like repositories. The repositories project had a reference to EF, but the UI project didn't (because it didn't need one, it just needed to reference the other projects). After I installed EF for the UI project as well, everything started working. This is why, it added this piece of code to my Web.config:

<entityFramework>
  <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
  <providers>
    <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
  </providers>
</entityFramework>

Span inside anchor or anchor inside span or doesn't matter?

Personally, as a web developer, I only ever put a span within an anchor tag if I am trying to highlight a section of the links text, such as applying a background to one section.

In STL maps, is it better to use map::insert than []?

One note is that you can also use Boost.Assign:

using namespace std;
using namespace boost::assign; // bring 'map_list_of()' into scope

void something()
{
    map<int,int> my_map = map_list_of(1,2)(2,3)(3,4)(4,5)(5,6);
}

What is the difference between Cygwin and MinGW?

Cygwin is is a Unix-like environment and command-line interface for Microsoft Windows.

Mingw is a native software port of the GNU Compiler Collection (GCC) to Microsoft Windows, along with a set of freely distributable import libraries and header files for the Windows API. MinGW allows developers to create native Microsoft Windows applications.

You can run binaries generated with mingw without the cygwin environment, provided that all necessary libraries (DLLs) are present.

What does @@variable mean in Ruby?

The answers are partially correct because @@ is actually a class variable which is per class hierarchy meaning it is shared by a class, its instances and its descendant classes and their instances.

class Person
  @@people = []

  def initialize
    @@people << self
  end

  def self.people
    @@people
  end
end

class Student < Person
end

class Graduate < Student
end

Person.new
Student.new

puts Graduate.people

This will output

#<Person:0x007fa70fa24870>
#<Student:0x007fa70fa24848>

So there is only one same @@variable for Person, Student and Graduate classes and all class and instance methods of these classes refer to the same variable.

There is another way of defining a class variable which is defined on a class object (Remember that each class is actually an instance of something which is actually the Class class but it is another story). You use @ notation instead of @@ but you can't access these variables from instance methods. You need to have class method wrappers.

class Person

  def initialize
    self.class.add_person self
  end

  def self.people
    @people
  end

  def self.add_person instance
    @people ||= []
    @people << instance
  end
end

class Student < Person
end

class Graduate < Student
end

Person.new
Person.new
Student.new
Student.new
Graduate.new
Graduate.new

puts Student.people.join(",")
puts Person.people.join(",")
puts Graduate.people.join(",")

Here, @people is single per class instead of class hierarchy because it is actually a variable stored on each class instance. This is the output:

#<Student:0x007f8e9d2267e8>,#<Student:0x007f8e9d21ff38>
#<Person:0x007f8e9d226158>,#<Person:0x007f8e9d226608>
#<Graduate:0x007f8e9d21fec0>,#<Graduate:0x007f8e9d21fdf8>

One important difference is that, you cannot access these class variables (or class instance variables you can say) directly from instance methods because @people in an instance method would refer to an instance variable of that specific instance of the Person or Student or Graduate classes.

So while other answers correctly state that @myvariable (with single @ notation) is always an instance variable, it doesn't necessarily mean that it is not a single shared variable for all instances of that class.

Install specific branch from github using Npm

you can give git pattern as version, yarn and npm are clever enough to resolve from a git repo.

yarn add any-package@user-name/repo-name#branch-name

or for npm

npm install --save any-package@user-name/repo-name#branch-name

How to assign a heredoc value to a variable in Bash?

$TEST="ok"
read MYTEXT <<EOT
this bash trick
should preserve
newlines $TEST
long live perl
EOT
echo -e $MYTEXT

What is the reason and how to avoid the [FIN, ACK] , [RST] and [RST, ACK]

Here is a rough explanation of the concepts.

[ACK] is the acknowledgement that the previously sent data packet was received.

[FIN] is sent by a host when it wants to terminate the connection; the TCP protocol requires both endpoints to send the termination request (i.e. FIN).

So, suppose

host A sends a data packet to host B
and then host B wants to close the connection.
Host B (depending on timing) can respond with [FIN,ACK] indicating that it received the sent packet and wants to close the session.
Host A should then respond with a [FIN,ACK] indicating that it received the termination request (the ACK part) and that it too will close the connection (the FIN part).

However, if host A wants to close the session after sending the packet, it would only send a [FIN] packet (nothing to acknowledge) but host B would respond with [FIN,ACK] (acknowledges the request and responds with FIN).

Finally, some TCP stacks perform half-duplex termination, meaning that they can send [RST] instead of the usual [FIN,ACK]. This happens when the host actively closes the session without processing all the data that was sent to it. Linux is one operating system which does just this.

You can find a more detailed and comprehensive explanation here.

System.Drawing.Image to stream C#

Use a memory stream

using(MemoryStream ms = new MemoryStream())
{
    image.Save(ms, ...);
    return ms.ToArray();
}

How to delete a folder and all contents using a bat file in windows?

@RD /S /Q "D:\PHP_Projects\testproject\Release\testfolder"

Explanation:

Removes (deletes) a directory.

RMDIR [/S] [/Q] [drive:]path RD [/S] [/Q] [drive:]path

/S      Removes all directories and files in the specified directory
        in addition to the directory itself.  Used to remove a directory
        tree.

/Q      Quiet mode, do not ask if ok to remove a directory tree with /S

How to remove non-alphanumeric characters?

[\W_]+

$string = preg_replace("/[\W_]+/u", '', $string);

It select all not A-Z, a-z, 0-9 and delete it.

See example here: https://regexr.com/3h1rj

Difference between two lists

var list3 = list1.Where(x => !list2.Any(z => z.Id == x.Id)).ToList();

Note: list3 will contain the items or objects that are not in both lists. Note: Its ToList() not toList()

Implement specialization in ER diagram

So I assume your permissions table has a foreign key reference to admin_accounts table. If so because of referential integrity you will only be able to add permissions for account ids exsiting in the admin accounts table. Which also means that you wont be able to enter a user_account_id [assuming there are no duplicates!]

How to Code Double Quotes via HTML Codes

Google recommend that you don't use any of them, source.

There is no need to use entity references like &mdash, &rdquo, or &#x263a, assuming the same encoding (UTF-8) is used for files and editors as well as among teams.

Is there a reason you can't simply use "?

Show special characters in Unix while using 'less' Command

For less use -u to display carriage returns (^M) and backspaces (^H), or -U to show the previous and tabs (^I) for example:

$ awk 'BEGIN{print "foo\bbar\tbaz\r\n"}' | less -U 
foo^Hbar^Ibaz^M

(END)

Without the -U switch the output would be:

fobar   baz

(END)

See man less for more exact description on the features.

reading a line from ifstream into a string variable

Use the std::getline() from <string>.

 istream & getline(istream & is,std::string& str)

So, for your case it would be:

std::getline(read,x);

Ruby: How to get the first character of a string

You can use Ruby's open classes to make your code much more readable. For instance, this:

class String
  def initial
    self[0,1]
  end
end

will allow you to use the initial method on any string. So if you have the following variables:

last_name = "Smith"
first_name = "John"

Then you can get the initials very cleanly and readably:

puts first_name.initial   # prints J
puts last_name.initial    # prints S

The other method mentioned here doesn't work on Ruby 1.8 (not that you should be using 1.8 anymore anyway!--but when this answer was posted it was still quite common):

puts 'Smith'[0]           # prints 83

Of course, if you're not doing it on a regular basis, then defining the method might be overkill, and you could just do it directly:

puts last_name[0,1]

How do I delete multiple rows with different IDs?

Delete from BA_CITY_MASTER where CITY_NAME in (select CITY_NAME from BA_CITY_MASTER group by CITY_NAME having count(CITY_NAME)>1);

How to use css style in php

Cascading Style Sheets (CSS) is a style sheet language used for describing the presentation semantics (the look and formatting) of a document written in a markup language. more info : http://en.wikipedia.org/wiki/Cascading_Style_Sheets CSS is not a programming language, and does not have the tools that come with a server side language like PHP. However, we can use Server-side languages to generate style sheets.

<html>
<head>
<title>...</title>
<style type="text/css">
table {
margin: 8px;
}

th {
font-family: Arial, Helvetica, sans-serif;
font-size: .7em;
background: #666;
color: #FFF;
padding: 2px 6px;
border-collapse: separate;
border: 1px solid #000;
}

td {
font-family: Arial, Helvetica, sans-serif;
font-size: .7em;
border: 1px solid #DDD;
}
</style>
</head>
<body>
<?php>
echo "<table>";
echo "<tr><th>ID</th><th>hashtag</th></tr>";
while($row = mysql_fetch_row($result))
{
echo "<tr onmouseover=\"hilite(this)\" onmouseout=\"lowlite(this)\"><td>$row[0]</td>                <td>$row[1]</td></tr>\n";
}
echo "</table>";
?>
</body>
</html>

The entity cannot be constructed in a LINQ to Entities query

You can project into anonymous type, and then from it to model type

public IEnumerable<Product> GetProducts(int categoryID)
{
    return (from p in Context.Set<Product>()
            where p.CategoryID == categoryID
            select new { Name = p.Name }).ToList()
           .Select(x => new Product { Name = x.Name });
}

Edit: I am going to be a bit more specific since this question got a lot of attention.

You cannot project into model type directly (EF restriction), so there is no way around this. The only way is to project into anonymous type (1st iteration), and then to model type (2nd iteration).

Please also be aware that when you partially load entities in this manner, they cannot be updated, so they should remain detached, as they are.

I never did completely understand why this is not possible, and the answers on this thread do not give strong reasons against it (mostly speaking about partially loaded data). It is correct that in partially loaded state entity cannot be updated, but then, this entity would be detached, so accidental attempts to save them would not be possible.

Consider method I used above: we still have a partially loaded model entity as a result. This entity is detached.

Consider this (wish-to-exist) possible code:

return (from p in Context.Set<Product>()
        where p.CategoryID == categoryID
        select new Product { Name = p.Name }).AsNoTracking().ToList();

This could also result in a list of detached entities, so we would not need to make two iterations. A compiler would be smart to see that AsNoTracking() has been used, which will result in detached entities, so it could allow us to do this. If, however, AsNoTracking() was omitted, it could throw the same exception as it is throwing now, to warn us that we need to be specific enough about the result we want.

How to make div go behind another div?

You need to add z-index to the divs, with a positive number for the top div and negative for the div below

example

NSURLErrorDomain error codes description

The NSURLErrorDomain error codes are listed here https://developer.apple.com/documentation/foundation/1508628-url_loading_system_error_codes

However, 400 is just the http status code (http://www.w3.org/Protocols/HTTP/HTRESP.html) being returned which means you've got something wrong with your request.

How to Reload ReCaptcha using JavaScript?

if you are using new recaptcha 2.0 use this: for code behind:

ScriptManager.RegisterStartupScript(this, this.GetType(), "CaptchaReload", "$.getScript(\"https://www.google.com/recaptcha/api.js\", function () {});", true);

for simple javascript

<script>$.getScript(\"https://www.google.com/recaptcha/api.js\", function () {});</script>

Difference between e.target and e.currentTarget

Ben is completely correct in his answer - so keep what he says in mind. What I'm about to tell you isn't a full explanation, but it's a very easy way to remember how e.target, e.currentTarget work in relation to mouse events and the display list:

e.target = The thing under the mouse (as ben says... the thing that triggers the event). e.currentTarget = The thing before the dot... (see below)

So if you have 10 buttons inside a clip with an instance name of "btns" and you do:

btns.addEventListener(MouseEvent.MOUSE_OVER, onOver);
// btns = the thing before the dot of an addEventListener call
function onOver(e:MouseEvent):void{
  trace(e.target.name, e.currentTarget.name);
}

e.target will be one of the 10 buttons and e.currentTarget will always be the "btns" clip.

It's worth noting that if you changed the MouseEvent to a ROLL_OVER or set the property btns.mouseChildren to false, e.target and e.currentTarget will both always be "btns".

Singleton with Arguments in Java

"A singleton with parameters is not a singleton" statement is not completely correct. We need to analyze this from the application perspective rather than from the code perspective.

We build singleton class to create a single instance of an object in one application run. By having a constructor with parameter, you can build flexibility into your code to change some attributes of your singleton object every time you run you application. This is not a violation of Singleton pattern. It looks like a violation if you see this from code perspective.

Design Patterns are there to help us write flexible and extendable code, not to hinder us writing good code.

In Spring MVC, how can I set the mime type header when using @ResponseBody

Register org.springframework.http.converter.json.MappingJacksonHttpMessageConverter as the message converter and return the object directly from the method.

<bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
  <property name="webBindingInitializer">
    <bean class="org.springframework.web.bind.support.ConfigurableWebBindingInitializer"/>
  </property>
  <property name="messageConverters">
    <list>
      <bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter"/>
    </list>
  </property>
</bean>

and the controller:

@RequestMapping(method=RequestMethod.GET, value="foo/bar")
public @ResponseBody Object fooBar(){
    return myService.getActualObject();
}

This requires the dependency org.springframework:spring-webmvc.

How to access environment variable values?

.env File

Here is my .env file (I changed multiple characters in each key to prevent people hacking my accounts).

SECRET_KEY=6g18169690e33af0cb10f3eb6b3cb36cb448b7d31f751cde
AWS_SECRET_ACCESS_KEY=18df6c6e95ab3832c5d09486779dcb1466ebbb12b141a0c4
DATABASE_URL='postgres://drjpczkqhnuvkc:f0ba6afd133c53913a4df103187b2a34c14234e7ae4b644952534c4dba74352d@ec2-54-146-4-66.compute-1.amazonaws.com:5432/ddnl5mnb76cne4'
AWS_ACCESS_KEY_ID=AKIBUGFPPLQFTFVDVIFE
DISABLE_COLLECTSTATIC=1
EMAIL_HOST_PASSWORD=COMING SOON
MAILCHIMP_API_KEY=a9782cc1adcd8160907ab76064411efe-us17
MAILCHIMP_EMAIL_LIST_ID=5a6a2c63b7
STRIPE_PUB_KEY=pk_test_51HEF86ARPAz7urwyGw9xwLkgbgfCYT48LttlwjEkb88I7Ljb5soBtuKXBaPiKfuu0Cx2BzIowR3jJFkC8ybFBAEf00DFY46tB8
STRIPE_SECRET_KEY=sk_test_19HEF55BCEAz7urwytx7tO3QCxV4R8DEFXbqj6esg7OKuybiSTI8iJD8mmJUQpg4RKENxuS04DKOCzYHpDkAjUttO00LOmsT5Eg

settings

I was told my data was corrupted. I was struggling to work out what was going on. I had a suspicion the values from .env were not being passed into my settings file.

print(os.environ.get('AWS_SECRET_ACCESS_KEY'))
print(os.environ.get('AWS_ACCESS_KEY_ID'))
print(os.environ.get('AWS_SECRET_ACCESS_KEY'))
print(os.environ.get('DATABASE_URL'))
print(os.environ.get('SECRET_KEY'))
print(os.environ.get('DISABLE_COLLECTSTATIC'))
print(os.environ.get('EMAIL_HOST_PASSWORD'))
print(os.environ.get('MAILCHIMP_API_KEY'))
print(os.environ.get('MAILCHIMP_EMAIL_LIST_ID'))
print(os.environ.get('STRIPE_PUB_KEY'))
print(os.environ.get('STRIPE_SECRET_KEY'))

The only value being printed correctly was the SECRET_KEY. I reviewed the .env file and for the life of me could not see any reason why the SECRET_KEY was working and nothing else.

I got everything working eventually by putting this above the print statements.

from dotenv import load_dotenv   #for python-dotenv method
load_dotenv()                    #for python-dotenv method

And doing

pip install -U python-dotenv

I am still not sure why SECRET_KEY was working when all the others were broken.

Add and remove attribute with jquery

It's because you've removed the id which is how you're finding the element. This line of code is trying to add id="page_navigation1" to an element with the id named page_navigation1, but it doesn't exist (because you deleted the attribute):

$("#page_navigation1").attr("id","page_navigation1");

Demo:

If you want to add and remove a class that makes your <div> red use:

$( '#page_navigation1' ).addClass( 'red-class' );

And:

$( '#page_navigation1' ).removeClass( 'red-class' );

Where red-class is:

.red-class {
    background-color: red;
}

How can I pass an argument to a PowerShell script?

You can use also the $args variable (that's like position parameters):

$step = $args[0]

$iTunes = New-Object -ComObject iTunes.Application

if ($iTunes.playerstate -eq 1)
{
  $iTunes.PlayerPosition = $iTunes.PlayerPosition + $step
}

Then it can be called like:

powershell.exe -file itunersforward.ps1 15

Find all table names with column name?

Please try the below query. Use sys.columns to get the details :-

SELECT c.name AS ColName, t.name AS TableName
FROM sys.columns c
    JOIN sys.tables t ON c.object_id = t.object_id
WHERE c.name LIKE '%MyCol%';

How to check if a variable exists in a FreeMarker template?

I think a lot of people are wanting to be able to check to see if their variable is not empty as well as if it exists. I think that checking for existence and emptiness is a good idea in a lot of cases, and makes your template more robust and less prone to silly errors. In other words, if you check to make sure your variable is not null AND not empty before using it, then your template becomes more flexible, because you can throw either a null variable or an empty string into it, and it will work the same in either case.

<#if p?? && p?has_content>1</#if>

Let's say you want to make sure that p is more than just whitespace. Then you could trim it before checking to see if it has_content.

<#if p?? && p?trim?has_content>1</#if>

UPDATE

Please ignore my suggestion -- has_content is all that is needed, as it does a null check along with the empty check. Doing p?? && p?has_content is equivalent to p?has_content, so you may as well just use has_content.

How to print to the console in Android Studio?

Be careful when using Logcat, it will truncate your message after ~4,076 bytes which can cause a lot of headache if you're printing out large amounts of data.

To get around this you have to write a function that will break it up into multiple parts like so.

Different color for each bar in a bar chart; ChartJS

here is how I dealed: I pushed an array "colors", with same number of entries than number of datas. For this I added a function "getRandomColor" at the end of the script. Hope it helps...

for (var i in arr) {
    customers.push(arr[i].customer);
    nb_cases.push(arr[i].nb_cases);
    colors.push(getRandomColor());
}

window.onload = function() {
    var config = {
        type: 'pie',
        data: {
            labels: customers,
            datasets: [{
                label: "Nomber of cases by customers",
                data: nb_cases,
                fill: true,
                backgroundColor: colors 
            }]
        },
        options: {
            responsive: true,
            title: {
                display: true,
                text: "Cases by customers"
            },
        }
    };

    var ctx = document.getElementById("canvas").getContext("2d");
    window.myLine = new Chart(ctx, config);
};

function getRandomColor() {
    var letters = '0123456789ABCDEF'.split('');
    var color = '#';
    for (var i = 0; i < 6; i++) {
        color += letters[Math.floor(Math.random() * 16)];
    }
    return color;
}

Inline onclick JavaScript variable

Yes, JavaScript variables will exist in the scope they are created.

var bannerID = 55;

<input id="EditBanner" type="button" 
  value="Edit Image" onclick="EditBanner(bannerID);"/>


function EditBanner(id) {
   //Do something with id
}

If you use event handlers and jQuery it is simple also

$("#EditBanner").click(function() {
   EditBanner(bannerID);
});

Default value in an asp.net mvc view model

What will you have? You'll probably end up with a default search and a search that you load from somewhere. Default search requires a default constructor, so make one like Dismissile has already suggested.

If you load the search criteria from elsewhere, then you should probably have some mapping logic.

How can I do an OrderBy with a dynamic string parameter?

The simplest & the best solution:

mylist.OrderBy(s => s.GetType().GetProperty("PropertyName").GetValue(s));

How to create the most compact mapping n ? isprime(n) up to a limit N?

In Python 3:

def is_prime(a):
    if a < 2:
        return False
    elif a!=2 and a % 2 == 0:
        return False
    else:
        return all (a % i for i in range(3, int(a**0.5)+1))

Explanation: A prime number is a number only divisible by itself and 1. Ex: 2,3,5,7...

1) if a<2: if "a" is less than 2 it is not a prime.

2) elif a!=2 and a % 2 == 0: if "a" is divisible by 2 then its definitely not a prime. But if a=2 we don't want to evaluate that as it is a prime number. Hence the condition a!=2

3) return all (a % i for i in range(3, int(a0.5)+1) ):** First look at what all() command does in python. Starting from 3 we divide "a" till its square root (a**0.5). If "a" is divisible the output will be False. Why square root? Let's say a=16. The square root of 16 = 4. We don't need to evaluate till 15. We only need to check till 4 to say that it's not a prime.

Extra: A loop for finding all the prime number within a range.

for i in range(1,100):
    if is_prime(i):
        print("{} is a prime number".format(i))

SQLite select where empty?

It looks like you can simply do:

SELECT * FROM your_table WHERE some_column IS NULL OR some_column = '';

Test case:

CREATE TABLE your_table (id int, some_column varchar(10));

INSERT INTO your_table VALUES (1, NULL);
INSERT INTO your_table VALUES (2, '');
INSERT INTO your_table VALUES (3, 'test');
INSERT INTO your_table VALUES (4, 'another test');
INSERT INTO your_table VALUES (5, NULL);

Result:

SELECT id FROM your_table WHERE some_column IS NULL OR some_column = '';

id        
----------
1         
2         
5

java.util.Date format SSSSSS: if not microseconds what are the last 3 digits?

SSSSSS is microseconds. Let us say the time is 10:30:22 (Seconds 22) and 10:30:22.1 would be 22 seconds and 1/10 of a second . Extending the same logic , 10:32.22.000132 would be 22 seconds and 132/1,000,000 of a second, which is nothing but microseconds.

Add space between HTML elements only using CSS

If you want to align various items and you like to have same margin around all sides, you can use the following. Each element withing container, regardless of type, will receive the same surrounding margin.

.container {
  display: flex;
}
.container > * {
  margin: 5px;
}

If you wish to align items in a row, but have the first element touch the leftmost edge of container, and have all other elements be equally spaced, you can use this:

.container {
  display: flex;
}
.container > :first-child {
  margin-right: 5px;
}
.container > *:not(:first-child) {
  margin: 5px;
}

how to initialize a char array?

Absent a really good reason to do otherwise, I'd probably use:

std::vector<char> msg(65546, '\0');

awk - concatenate two string variable and assign to a third

You can also concatenate strings from across multiple lines with whitespaces.

$ cat file.txt
apple 10
oranges 22
grapes 7

Example 1:

awk '{aggr=aggr " " $2} END {print aggr}' file.txt
10 22 7

Example 2:

awk '{aggr=aggr ", " $1 ":" $2} END {print aggr}' file.txt
, apple:10, oranges:22, grapes:7

How to tell if node.js is installed or not

Ctrl + R - to open the command line and then writes:

node -v

How to configure WAMP (localhost) to send email using Gmail?

use stunnel on your server, to send with gmail. google it.

Excel add one hour

This may help you as well. This is a conditional statement that will fill the cell with a default date if it is empty but will subtract one hour if it is a valid date/time and put it into the cell.

=IF((Sheet1!C4)="",DATE(1999,1,1),Sheet1!C4-TIME(1,0,0))

You can also substitute TIME with DATE to add or subtract a date or time.

Access blocked by CORS policy: Response to preflight request doesn't pass access control check

If you are using Spring as Back-End server and especially using Spring Security then i found a solution by putting http.cors(); in the configure method. The method looks like that:

protected void configure(HttpSecurity http) throws Exception {
        http
                .csrf().disable()
                .authorizeRequests() // authorize
                .anyRequest().authenticated() // all requests are authenticated
                .and()
                .httpBasic();

        http.cors();
}

SQL Query - how do filter by null or not null

set ansi_nulls off go select * from table t inner join otherTable o on t.statusid = o.statusid go set ansi_nulls on go

remove kernel on jupyter notebook

jupyter kernelspec remove now exists, see #7934.

So you can just.

# List all kernels and grap the name of the kernel you want to remove
jupyter kernelspec list
# Remove it
jupyter kernelspec remove <kernel_name>

That's it.

Why does .NET foreach loop throw NullRefException when collection is null?

A foreach loop calls the GetEnumerator method.
If the collection is null, this method call results in a NullReferenceException.

It is bad practice to return a null collection; your methods should return an empty collection instead.

Is div inside list allowed?

If I recall correctly, a div inside a li used to be invalid.

@Flower @Superstringcheese Div should semantically define a section of a document, but it has already practically lost this role. Span should however contain text.

How to sum columns in a dataTable?

Try this:

            DataTable dt = new DataTable();
            int sum = 0;
            foreach (DataRow dr in dt.Rows)
            {
                foreach (DataColumn dc in dt.Columns)
                {
                    sum += (int)dr[dc];
                }
            }

Pretty print in MongoDB shell as default

Give a try to Mongo-hacker(node module), it alway prints pretty. https://github.com/TylerBrock/mongo-hacker

More it enhances mongo shell (supports only ver>2.4, current ver is 3.0), like

Colorization
Additional shell commands (count documents/count docs/etc)
API Additions (db.collection.find({ ... }).last(), db.collection.find({ ... }).reverse(), etc)
Aggregation Framework

I am using for while in production env, no problems yet.

In jQuery, what's the best way of formatting a number to 2 decimal places?

If you're doing this to several fields, or doing it quite often, then perhaps a plugin is the answer.
Here's the beginnings of a jQuery plugin that formats the value of a field to two decimal places.
It is triggered by the onchange event of the field. You may want something different.

<script type="text/javascript">

    // mini jQuery plugin that formats to two decimal places
    (function($) {
        $.fn.currencyFormat = function() {
            this.each( function( i ) {
                $(this).change( function( e ){
                    if( isNaN( parseFloat( this.value ) ) ) return;
                    this.value = parseFloat(this.value).toFixed(2);
                });
            });
            return this; //for chaining
        }
    })( jQuery );

    // apply the currencyFormat behaviour to elements with 'currency' as their class
    $( function() {
        $('.currency').currencyFormat();
    });

</script>   
<input type="text" name="one" class="currency"><br>
<input type="text" name="two" class="currency">

Why is "using namespace std;" considered bad practice?

Do not use it globally

It is considered "bad" only when used globally. Because:

You clutter the namespace you are programming in.
Readers will have difficulty seeing where a particular identifier comes from, when you use many using namespace xyz.
Whatever is true for other readers of your source code is even more true for the most frequent reader of it: yourself. Come back in a year or two and take a look...
If you only talk about using namespace std you might not be aware of all the stuff you grab -- and when you add another #include or move to a new C++ revision you might get name conflicts you were not aware of.

You may use it locally

Go ahead and use it locally (almost) freely. This, of course, prevents you from repetition of std:: -- and repetition is also bad.

An idiom for using it locally

In C++03 there was an idiom -- boilerplate code -- for implementing a swap function for your classes. It was suggested that you actually use a local using namespace std -- or at least using std::swap:

class Thing {
    int    value_;
    Child  child_;
public:
    // ...
    friend void swap(Thing &a, Thing &b);
};
void swap(Thing &a, Thing &b) {
    using namespace std;      // make `std::swap` available
    // swap all members
    swap(a.value_, b.value_); // `std::stwap(int, int)`
    swap(a.child_, b.child_); // `swap(Child&,Child&)` or `std::swap(...)`
}

This does the following magic:

The compiler will choose the std::swap for value_, i.e. void std::swap(int, int).
If you have an overload void swap(Child&, Child&) implemented the compiler will choose it.
If you do not have that overload the compiler will use void std::swap(Child&,Child&) and try its best swapping these.

With C++11 there is no reason to use this pattern any more. The implementation of std::swap was changed to find a potential overload and choose it.

Difference between Grunt, NPM and Bower ( package.json vs bower.json )

Npm and Bower are both dependency management tools. But the main difference between both is npm is used for installing Node js modules but bower js is used for managing front end components like html, css, js etc.

A fact that makes this more confusing is that npm provides some packages which can be used in front-end development as well, like grunt and jshint.

These lines add more meaning

Bower, unlike npm, can have multiple files (e.g. .js, .css, .html, .png, .ttf) which are considered the main file(s). Bower semantically considers these main files, when packaged together, a component.

Edit: Grunt is quite different from Npm and Bower. Grunt is a javascript task runner tool. You can do a lot of things using grunt which you had to do manually otherwise. Highlighting some of the uses of Grunt:

Zipping some files (e.g. zipup plugin)
Linting on js files (jshint)
Compiling less files (grunt-contrib-less)

There are grunt plugins for sass compilation, uglifying your javascript, copy files/folders, minifying javascript etc.

Please Note that grunt plugin is also an npm package.

Question-1

When I want to add a package (and check in the dependency into git), where does it belong - into package.json or into bower.json

It really depends where does this package belong to. If it is a node module(like grunt,request) then it will go in package.json otherwise into bower json.

Question-2

When should I ever install packages explicitly like that without adding them to the file that manages dependencies

It does not matter whether you are installing packages explicitly or mentioning the dependency in .json file. Suppose you are in the middle of working on a node project and you need another project, say request, then you have two options:

Edit the package.json file and add a dependency on 'request'
npm install

Use commandline: npm install --save request

--save options adds the dependency to package.json file as well. If you don't specify --save option, it will only download the package but the json file will be unaffected.

You can do this either way, there will not be a substantial difference.

How to get the file name from a full path using JavaScript?

In Node.js, you can use Path's parse module...

var path = require('path');
var file = '/home/user/dir/file.txt';

var filename = path.parse(file).base;
//=> 'file.txt'

Adding input elements dynamically to form

You could use an onclick event handler in order to get the input value for the text field. Make sure you give the field an unique id attribute so you can refer to it safely through document.getElementById():

If you want to dynamically add elements, you should have a container where to place them. For instance, a <div id="container">. Create new elements by means of document.createElement(), and use appendChild() to append each of them to the container. You might be interested in outputting a meaningful name attribute (e.g. name="member"+i for each of the dynamically generated <input>s if they are to be submitted in a form.

Notice you could also create <br/> elements with document.createElement('br'). If you want to just output some text, you can use document.createTextNode() instead.

Also, if you want to clear the container every time it is about to be populated, you could use hasChildNodes() and removeChild() together.

_x000D_

<html>
<head>
    <script type='text/javascript'>
        function addFields(){
            // Number of inputs to create
            var number = document.getElementById("member").value;
            // Container <div> where dynamic content will be placed
            var container = document.getElementById("container");
            // Clear previous contents of the container
            while (container.hasChildNodes()) {
                container.removeChild(container.lastChild);
            }
            for (i=0;i<number;i++){
                // Append a node with a random text
                container.appendChild(document.createTextNode("Member " + (i+1)));
                // Create an <input> element, set its type and name attributes
                var input = document.createElement("input");
                input.type = "text";
                input.name = "member" + i;
                container.appendChild(input);
                // Append a line break 
                container.appendChild(document.createElement("br"));
            }
        }
    </script>
</head>
<body>
    <input type="text" id="member" name="member" value="">Number of members: (max. 10)<br />
    <a href="#" id="filldetails" onclick="addFields()">Fill Details</a>
    <div id="container"/>
</body>
</html>

_x000D_

See a working sample in this JSFiddle.

Chrome: console.log, console.debug are not working

In my case it was just an old cached Javascript file. After clearing the cache I saw my logs.

100% width table overflowing div container

Add display: block; and overflow: auto; to .my-table. This will simply cut off anything past the 280px limit you enforced. There's no way to make it "look pretty" with that requirement due to words like pélagosthrough which are wider than 280px.

How to remove empty lines with or without whitespace in Python

Same as what @NullUserException said, this is how I write it:

removedWhitespce = re.sub(r'^\s*$', '', line)

How to group time by hour or by 10 minutes

I'm super late to the party, but this doesn't appear in any of the existing answers:

GROUP BY DATEADD(MINUTE, DATEDIFF(MINUTE, '2000', date_column) / 10 * 10, '2000')

The 10 and MINUTE terms can be changed to any number and DATEPART, respectively.
It is a DATETIME value, which means:
- It works fine across long time intervals. (There is no collision between years.)
- Including it in the SELECT statement will give your output a column with pretty output truncated at the level you specify.
'2000' is an "anchor date" around which SQL will perform the date math. Jereonh discovered below that you encounter an integer overflow with the previous anchor (0) when you group recent dates by seconds or milliseconds.^†

SELECT   DATEADD(MINUTE, DATEDIFF(MINUTE, '2000', aa.[date]) / 10 * 10, '2000')
                                                               AS [date_truncated],
         COUNT(*) AS [records_in_interval],
         AVG(aa.[value]) AS [average_value]
FROM     [friib].[dbo].[archive_analog] AS aa
GROUP BY DATEADD(MINUTE, DATEDIFF(MINUTE, '2000', aa.[date]) / 10 * 10, '2000')
ORDER BY [date_truncated]

If your data spans centuries,^‡ using a single anchor date for second- or millisecond grouping will still encounter the overflow. If that is happening, you can ask each row to anchor the binning comparison to its own date's midnight:

Use DATEADD(DAY, DATEDIFF(DAY, 0, aa.[date]), 0) instead of '2000' wherever it appears above. Your query will be totally unreadable, but it will work.
An alternative might be CONVERT(DATETIME, CONVERT(DATE, aa.[date])) as the replacement.

_{^† 2³² ˜ 4.29E+9, so if your DATEPART is SECOND, you get 4.3 billion seconds on either side, or "anchor ± 136 years." Similarly, 2³² milliseconds is ˜ 49.7 days.}
_{^‡ If your data actually spans centuries or millenia and is still accurate to the second or millisecond… congratulations! Whatever you're doing, keep doing it.}

Determine the number of rows in a range

Sheet1.Range("myrange").Rows.Count

What's the difference between Git Revert, Checkout and Reset?

These three commands have entirely different purposes. They are not even remotely similar.

`git revert`

This command creates a new commit that undoes the changes from a previous commit. This command adds new history to the project (it doesn't modify existing history).

`git checkout`

This command checks-out content from the repository and puts it in your work tree. It can also have other effects, depending on how the command was invoked. For instance, it can also change which branch you are currently working on. This command doesn't make any changes to the history.

`git reset`

This command is a little more complicated. It actually does a couple of different things depending on how it is invoked. It modifies the index (the so-called "staging area"). Or it changes which commit a branch head is currently pointing at. This command may alter existing history (by changing the commit that a branch references).

Using these commands

If a commit has been made somewhere in the project's history, and you later decide that the commit is wrong and should not have been done, then git revert is the tool for the job. It will undo the changes introduced by the bad commit, recording the "undo" in the history.

If you have modified a file in your working tree, but haven't committed the change, then you can use git checkout to checkout a fresh-from-repository copy of the file.

If you have made a commit, but haven't shared it with anyone else and you decide you don't want it, then you can use git reset to rewrite the history so that it looks as though you never made that commit.

These are just some of the possible usage scenarios. There are other commands that can be useful in some situations, and the above three commands have other uses as well.

Web-scraping JavaScript page with Python

You'll want to use urllib, requests, beautifulSoup and selenium web driver in your script for different parts of the page, (to name a few).
Sometimes you'll get what you need with just one of these modules.
Sometimes you'll need two, three, or all of these modules.
Sometimes you'll need to switch off the js on your browser.
Sometimes you'll need header info in your script.
No websites can be scraped the same way and no website can be scraped in the same way forever without having to modify your crawler, usually after a few months. But they can all be scraped! Where there's a will there's a way for sure.
If you need scraped data continuously into the future just scrape everything you need and store it in .dat files with pickle.
Just keep searching how to try what with these modules and copying and pasting your errors into the Google.

How do I spool to a CSV formatted file using SQLPLUS?

I wrote this purely SQLPlus script to dump tables to CSV in 1994.

As noted in the script comments, someone at Oracle put my script in an Oracle Support note, but without attribution.

https://github.com/jkstill/oracle-script-lib/blob/master/sql/dump.sql

The script also also builds a control file and a parameter file for SQL*LOADER

What exactly are iterator, iterable, and iteration?

Here's the explanation I use in teaching Python classes:

An ITERABLE is:

anything that can be looped over (i.e. you can loop over a string or file) or
anything that can appear on the right-side of a for-loop: for x in iterable: ... or
anything you can call with iter() that will return an ITERATOR: iter(obj) or
an object that defines __iter__ that returns a fresh ITERATOR, or it may have a __getitem__ method suitable for indexed lookup.

An ITERATOR is an object:

with state that remembers where it is during iteration,
with a __next__ method that:
- returns the next value in the iteration
- updates the state to point at the next value
- signals when it is done by raising StopIteration
and that is self-iterable (meaning that it has an __iter__ method that returns self).

Notes:

The __next__ method in Python 3 is spelt next in Python 2, and
The builtin function next() calls that method on the object passed to it.

For example:

>>> s = 'cat'      # s is an ITERABLE
                   # s is a str object that is immutable
                   # s has no state
                   # s has a __getitem__() method 

>>> t = iter(s)    # t is an ITERATOR
                   # t has state (it starts by pointing at the "c"
                   # t has a next() method and an __iter__() method

>>> next(t)        # the next() function returns the next value and advances the state
'c'
>>> next(t)        # the next() function returns the next value and advances
'a'
>>> next(t)        # the next() function returns the next value and advances
't'
>>> next(t)        # next() raises StopIteration to signal that iteration is complete
Traceback (most recent call last):
...
StopIteration

>>> iter(t) is t   # the iterator is self-iterable

What's the correct way to convert bytes to a hex string in Python 3?

Since Python 3.5 this is finally no longer awkward:

>>> b'\xde\xad\xbe\xef'.hex()
'deadbeef'

and reverse:

>>> bytes.fromhex('deadbeef')
b'\xde\xad\xbe\xef'

works also with the mutable bytearray type.

Reference: https://docs.python.org/3/library/stdtypes.html#bytes.hex

Vertical line using XML drawable

its very simple... to add a vertical line in android xml...

<View
android:layout_width="fill_parent"
android:layout_height="1dp"
android:layout_marginTop="5dp"
android:rotation="90"
android:background="@android:color/darker_gray"/>

How to delete Tkinter widgets from a window?

One way you can do it, is to get the slaves list from the frame that needs to be cleared and destroy or "hide" them according to your needs. To get a clear frame you can do it like this:

from tkinter import *

root = Tk()

def clear():
    list = root.grid_slaves()
    for l in list:
        l.destroy()

Label(root,text='Hello World!').grid(row=0)
Button(root,text='Clear',command=clear).grid(row=1)

root.mainloop()

You should call grid_slaves(), pack_slaves() or slaves() depending on the method you used to add the widget to the frame.

Calculating Time Difference

Here is a piece of code to do so:

def(StringChallenge(str1)):

#str1 = str1[1:-1]
h1 = 0
h2 = 0
m1 = 0
m2 = 0

def time_dif(h1,m1,h2,m2):
    if(h1 == h2):
        return m2-m1
    else:
        return ((h2-h1-1)*60 + (60-m1) + m2)
count_min = 0

if str1[1] == ':':
    h1=int(str1[:1])
    m1=int(str1[2:4])
else:
    h1=int(str1[:2])
    m1=int(str1[3:5])

if str1[-7] == '-':
    h2=int(str1[-6])
    m2=int(str1[-4:-2])
else:
    h2=int(str1[-7:-5])
    m2=int(str1[-4:-2])

if h1 == 12:
    h1 = 0
if h2 == 12:
    h2 = 0

if "am" in str1[:8]:
    flag1 = 0
else:
    flag1= 1

if "am" in str1[7:]:
    flag2 = 0
else:
    flag2 = 1

if flag1 == flag2:
    if h2 > h1 or (h2 == h1 and m2 >= m1):
        count_min += time_dif(h1,m1,h2,m2)
    else:
        count_min += 1440 - time_dif(h2,m2,h1,m1)
else:
    count_min += (12-h1-1)*60
    count_min += (60 - m1)
    count_min += (h2*60)+m2


return count_min

How do I fit an image (img) inside a div and keep the aspect ratio?

Setting the photo as a background image will give us more control over size and placement, leaving the img tag to serve a different purpose...

Below, if we want the div to be the same aspect ratio as the photo, then placeholder.png is a small transparent image with the same aspect ratio as photo.jpg. If the photo is a square, it's a 1px x 1px placeholder, if the photo is a video thumbnail, it's a 16x9 placeholder, etc.

Specific to the question, use a 1x1 placeholder to maintain the div's square ratio, with a background image using background-size to maintain the photo's aspect ratio.

I used background-position: center center; so the photo will be centered in the div. (Aligning the photo in the vertical center or bottom would get ugly with the photo in the img tag.)

div {
    background: url(photo.jpg) center center no-repeat;
    background-size: contain;
    width: 48px; // or a % in responsive layout
}
img {
    width: 100%;
}

<div><img src="placeholder.png"/></div>

To avoid an extra http request, convert the placeholder image to a data: URL.

<img src="data:image/png;base64,..."/>

How do I check in python if an element of a list is empty?

Just check if that element is equal to None type or make use of NOT operator ,which is equivalent to the NULL type you observe in other languages.

if not A[i]:
    ## do whatever

Anyway if you know the size of your list then you don't need to do all this.

How do I connect to my existing Git repository using Visual Studio Code?

Use git clone to clone your repository into a folder (say work). You should see a new subfolder, work/.git.
Open folder work in Visual Studio Code - everything should work fine!

PS: Blow away the temporary folder.

Android, getting resource ID from string?

Simple method to get resource ID:

public int getDrawableName(Context ctx,String str){
    return ctx.getResources().getIdentifier(str,"drawable",ctx.getPackageName());
}

How to count string occurrence in string?

Try it

<?php 
$str = "33,33,56,89,56,56";
echo substr_count($str, '56');
?>

<script type="text/javascript">
var temp = "33,33,56,89,56,56";
var count = temp.match(/56/g);  
alert(count.length);
</script>

Merging multiple PDFs using iTextSharp in c#.net

I found a very nice solution on this site : http://weblogs.sqlteam.com/mladenp/archive/2014/01/10/simple-merging-of-pdf-documents-with-itextsharp-5-4-5.aspx

I update the method in this mode :

    public static bool MergePDFs(IEnumerable<string> fileNames, string targetPdf)
    {
        bool merged = true;
        using (FileStream stream = new FileStream(targetPdf, FileMode.Create))
        {
            Document document = new Document();
            PdfCopy pdf = new PdfCopy(document, stream);
            PdfReader reader = null;
            try
            {
                document.Open();
                foreach (string file in fileNames)
                {
                    reader = new PdfReader(file);
                    pdf.AddDocument(reader);
                    reader.Close();
                }
            }
            catch (Exception)
            {
                merged = false;
                if (reader != null)
                {
                    reader.Close();
                }
            }
            finally
            {
                if (document != null)
                {
                    document.Close();
                }
            }
        }
        return merged;
    }

AngularJS directive does not update on scope variable changes

A simple solution is to make the scope variable object. Then access the content with {{ whatever-object.whatever-property }}. The variable is not updating because JavaScript pass Primitive type by value. Whereas Object are passed by reference which solves the problem.

ContractFilter mismatch at the EndpointDispatcher exception

I had this error and it was caused by the recevier contract not implementing the method being called. Basically, someone hadn't deployed the lastest version of the WCF service to the host server.

How to display a pdf in a modal window?

You can have an iframe inside the modal markup and give the src attribute of it as the link to your pdf. On click of the link you can show this modal markup.

HTML to PDF with Node.js

If you want to export HTML to PDF. You have many options. without node even

Option 1: Have a button on your html page that calls window.print() function. use the browsers native html to pdf. use media queries to make your html page look good on a pdf. and you also have the print before and after events that you can use to make changes to your page before print.

Option 2. htmltocanvas or rasterizeHTML. convert your html to canvas , then call toDataURL() on the canvas object to get the image . and use a JavaScript library like jsPDF to add that image to a PDF file. Disadvantage of this approach is that the pdf doesnt become editable. If you want data extracted from PDF, there is different ways for that.

Option 3. @Jozzhard answer

How do I convert hex to decimal in Python?

If by "hex data" you mean a string of the form

s = "6a48f82d8e828ce82b82"

you can use

i = int(s, 16)

to convert it to an integer and

str(i)

to convert it to a decimal string.

Angular ngClass and click event for toggling class

Angular6 using the renderer2 without any variables and a clean template:

template:

<div (click)="toggleClass($event,'testClass')"></div>

in ts:

toggleClass(event: any, class: string) {
  const hasClass = event.target.classList.contains(class);

  if(hasClass) {
    this.renderer.removeClass(event.target, class);
  } else {
    this.renderer.addClass(event.target, class);
  }
}

One could put this in a directive too ;)

PHP JSON String, escape Double Quotes for JS output

Use json_encode($json_array, JSON_HEX_QUOT); since php 5.3: http://php.net/manual/en/json.constants.php

How to get records randomly from the oracle database?

To randomly select 20 rows I think you'd be better off selecting the lot of them randomly ordered and selecting the first 20 of that set.

Something like:

Select *
  from (select *
          from table
         order by dbms_random.value) -- you can also use DBMS_RANDOM.RANDOM
 where rownum < 21;

Best used for small tables to avoid selecting large chunks of data only to discard most of it.

Programs & Examples On #Autotest

How to run a single RSpec test?

Cannot install packages inside docker Ubuntu image

Java way to check if a string is palindrome

Error to use a section registered as allowDefinition='MachineToApplication' beyond application level

Add Favicon to Website

In Java, what is the best way to determine the size of an object?

Find the least number of coins required that can make any change from 1 to 99 cents

Count all values in a matrix greater than a value

C# DataRow Empty-check

HTML Display Current date

Cell spacing in UICollectionView

Setting device orientation in Swift iOS

How to write to file in Ruby?

Java: Rotating Images

What does if [ $? -eq 0 ] mean for shell scripts?

How to cast List<Object> to List<MyClass>

how to set start value as "0" in chartjs?

Sending private messages to user

Reverse engineering from an APK file to a project

How to set Google Chrome in WebDriver

Create a one to many relationship using SQL Server

java.lang.ClassNotFoundException: com.mysql.jdbc.Driver in Eclipse

Scroll to bottom of Div on page load (jQuery)

How to increase Maximum Upload size in cPanel?

Ignoring upper case and lower case in Java

creating triggers for After Insert, After Update and After Delete in SQL

Concatenating variables and strings in React

Node.js Web Application examples/tutorials

How to programmatically send a 404 response with Express/Node?

How to get host name with port from a http or https request

Indirectly referenced from required .class file

DTO and DAO concepts and MVC

Why does Node.js' fs.readFile() return a buffer instead of string?

How to get array keys in Javascript?

Using client certificate in Curl command

More elegant way of declaring multiple variables at the same time

What does double question mark (??) operator mean in PHP

How read Doc or Docx file in java?

How to change the type of a field?

How to avoid "Permission denied" when using pip with virtualenv

DateTime.Now.ToString("yyyy-MM-dd hh:mm:ss") is returning AM time instead of PM time?

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

Why use String.Format?

Compiler error: memset was not declared in this scope

Iterate through Nested JavaScript Objects

Clean up a fork and restart it from the upstream

How to do it 100% through the Sourcetree GUI

Steps

How to uncompress a tar.gz in another directory

Spring data JPA query with parameter properties

How to convert List<Integer> to int[] in Java?

How do I change the default library path for R packages

Why does ENOENT mean "No such file or directory"?

How do I preserve line breaks when getting text from a textarea?

How to make the script wait/sleep in a simple way in unity

How to get the innerHTML of selectable jquery element?

How do I set the visibility of a text box in SSRS using an expression?

How to "wait" a Thread in Android

How do you use global variables or constant values in Ruby?

Execute an action when an item on the combobox is selected

java.sql.SQLException: Fail to convert to internal representation

jsonify a SQLAlchemy result set in Flask

Display rows with one or more NaN values in pandas dataframe

How to create a thread?

Django request.GET

How to access Winform textbox control from another class?

Easiest way to toggle 2 classes in jQuery

Are HTTP headers case-sensitive?

Do you have to put Task.Run in a method to make it async?

OpenSSL Verify return code: 20 (unable to get local issuer certificate)

When should I use File.separator and when File.pathSeparator?

How to determine if a string is a number with C++?

Convert string into Date type on Python

How do I get the file extension of a file in Java?

How to error handle 1004 Error with WorksheetFunction.VLookup?

Groovy / grails how to determine a data type?

Search for one value in any column of any table inside a database

Angular 2: import external js file into component

Make UINavigationBar transparent

Rounding BigDecimal to always have two decimal places