Programs & Examples On #Jtree

Java Swing component that displays a set of hierarchical data as an outline.

if (boolean condition) in Java

Suppose you want to check a boolean. If true, do something. Else, do something else. You can write:

if(condition==true){

}
else{   //else means this checks for the opposite of what you checked at if

}

instead of that, you can do it simply like:

if(condition){  //this will check if condition is true 

}
else{ 

}

Inversely. If you were to do something if condition was false and do something else if condition was true. Then you would write:

if(condition!=true){   //if(condition=false)

}
else{

}

But following the simple path. We do:

if(!condition){  //it reads out as: if condition is not true. Which means if condition is false right?

}
else{

}

Think about it. You'll get it in no time.

How to inject a Map using the @Value Spring Annotation?

You can inject values into a Map from the properties file using the @Value annotation like this.

The property in the properties file.

propertyname={key1:'value1',key2:'value2',....}

In your code.

@Value("#{${propertyname}}")  private Map<String,String> propertyname;

Note the hashtag as part of the annotation.

Google Maps Android API v2 - Interactive InfoWindow (like in original android google maps)

Just a speculation, I have not enough experience to try it... )-:

Since GoogleMap is a fragment, it should be possible to catch marker onClick event and show custom fragment view. A map fragment will be still visible on the background. Does anybody tried it? Any reason why it could not work?

The disadvantage is that map fragment would be freezed on backgroud, until a custom info fragment return control to it.

How merge two objects array in angularjs?

This works for me :

$scope.array1 = $scope.array1.concat(array2)

In your case it would be :

$scope.actions.data = $scope.actions.data.concat(data)

How do I create HTML table using jQuery dynamically?

I understand you want to create stuff dynamically. That does not mean you have to actually construct DOM elements to do it. You can just make use of html to achieve what you want .

Look at the code below :

HTML:

<table border="0" cellpadding="0" width="100%" id='providersFormElementsTable'></table>

JS :

createFormElement("Nickname","nickname")

function createFormElement(labelText, id) {

$("#providersFormElementsTable").html("<tr><td>Nickname</td><td><input type='text' id='"+id+"' name='nickname'></td><lable id='"+labelText+"'></lable></td></tr>");
$('#providersFormElementsTable').append('<br />');
}

This one does what you want dynamically, it just needs the id and labelText to make it work, which actually must be the only dynamic variables as only they will be changing. Your DOM structure will always remain the same .

WORKING DEMO:

Moreover, when you use the process you mentioned in your post you get only [object Object]. That is because when you call createProviderFormFields , it is a function call and hence it's returning an object for you. You will not be seeing the text box as it needs to be added . For that you need to strip individual content form the object, then construct the html from it.

It's much easier to construct just the html and change the id s of the label and input according to your needs.

How do I load a PHP file into a variable?

I suppose you want to get the content generated by PHP, if so use:

$Vdata = file_get_contents('http://YOUR_HOST/YOUR/FILE.php');

Otherwise if you want to get the source code of the PHP file, it's the same as a .txt file:

$Vdata = file_get_contents('path/to/YOUR/FILE.php');

Pylint "unresolved import" error in Visual Studio Code

Install code-runner and add the code below in the settings.json folder:

    "code-runner.executorMap": {
        "python": "python3 -u",
    }

"python": "(the Python executable with modules or its path) -u",

Amazon Interview Question: Design an OO parking lot

public class ParkingLot 
{
    Vector<ParkingSpace> vacantParkingSpaces = null;
    Vector<ParkingSpace> fullParkingSpaces = null;

    int parkingSpaceCount = 0;

    boolean isFull;
    boolean isEmpty;

    ParkingSpace findNearestVacant(ParkingType type)
    {
        Iterator<ParkingSpace> itr = vacantParkingSpaces.iterator();

        while(itr.hasNext())
        {
            ParkingSpace parkingSpace = itr.next();

            if(parkingSpace.parkingType == type)
            {
                return parkingSpace;
            }
        }
        return null;
    }

    void parkVehicle(ParkingType type, Vehicle vehicle)
    {
        if(!isFull())
        {
            ParkingSpace parkingSpace = findNearestVacant(type);

            if(parkingSpace != null)
            {
                parkingSpace.vehicle = vehicle;
                parkingSpace.isVacant = false;

                vacantParkingSpaces.remove(parkingSpace);
                fullParkingSpaces.add(parkingSpace);

                if(fullParkingSpaces.size() == parkingSpaceCount)
                    isFull = true;

                isEmpty = false;
            }
        }
    }

    void releaseVehicle(Vehicle vehicle)
    {
        if(!isEmpty())
        {
            Iterator<ParkingSpace> itr = fullParkingSpaces.iterator();

            while(itr.hasNext())
            {
                ParkingSpace parkingSpace = itr.next();

                if(parkingSpace.vehicle.equals(vehicle))
                {
                    fullParkingSpaces.remove(parkingSpace);
                    vacantParkingSpaces.add(parkingSpace);

                    parkingSpace.isVacant = true;
                    parkingSpace.vehicle = null;

                    if(vacantParkingSpaces.size() == parkingSpaceCount)
                        isEmpty = true;

                    isFull = false;
                }
            }
        }
    }

    boolean isFull()
    {
        return isFull;
    }

    boolean isEmpty()
    {
        return isEmpty;
    }
}

public class ParkingSpace 
{
    boolean isVacant;
    Vehicle vehicle;
    ParkingType parkingType;
    int distance;
}

public class Vehicle 
{
    int num;
}

public enum ParkingType
{
    REGULAR,
    HANDICAPPED,
    COMPACT,
    MAX_PARKING_TYPE,
}

Templated check for the existence of a class member function?

Well, this question has a long list of answers already, but I would like to emphasize the comment from Morwenn: there is a proposal for C++17 that makes it really much simpler. See N4502 for details, but as a self-contained example consider the following.

This part is the constant part, put it in a header.

// See http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/n4502.pdf.
template <typename...>
using void_t = void;

// Primary template handles all types not supporting the operation.
template <typename, template <typename> class, typename = void_t<>>
struct detect : std::false_type {};

// Specialization recognizes/validates only types supporting the archetype.
template <typename T, template <typename> class Op>
struct detect<T, Op, void_t<Op<T>>> : std::true_type {};

then there is the variable part, where you specify what you are looking for (a type, a member type, a function, a member function etc.). In the case of the OP:

template <typename T>
using toString_t = decltype(std::declval<T>().toString());

template <typename T>
using has_toString = detect<T, toString_t>;

The following example, taken from N4502, shows a more elaborate probe:

// Archetypal expression for assignment operation.
template <typename T>
using assign_t = decltype(std::declval<T&>() = std::declval<T const &>())

// Trait corresponding to that archetype.
template <typename T>
using is_assignable = detect<T, assign_t>;

Compared to the other implementations described above, this one is fairly simple: a reduced set of tools (void_t and detect) suffices, no need for hairy macros. Besides, it was reported (see N4502) that it is measurably more efficient (compile-time and compiler memory consumption) than previous approaches.

Here is a live example. It works fine with Clang, but unfortunately, GCC versions before 5.1 followed a different interpretation of the C++11 standard which caused void_t to not work as expected. Yakk already provided the work-around: use the following definition of void_t (void_t in parameter list works but not as return type):

#if __GNUC__ < 5 && ! defined __clang__
// https://stackoverflow.com/a/28967049/1353549
template <typename...>
struct voider
{
  using type = void;
};
template <typename...Ts>
using void_t = typename voider<Ts...>::type;
#else
template <typename...>
using void_t = void;
#endif

How to determine an object's class?

There is also an .isInstance method on the "Class" class. if you get an object's class via myBanana.getClass() you can see if your object myApple is an instance of the same class as myBanana via

myBanana.getClass().isInstance(myApple)

Get webpage contents with Python?

Also you can use faster_than_requests package. That's very fast and simple:

import faster_than_requests as r
content = r.get2str("http://test.com/")

Look at this comparison:

enter image description here

Undo working copy modifications of one file in Git?

This answers is for command needed for undoing local changes which are in multiple specific files in same or multiple folders (or directories). This answers specifically addresses question where a user has more than one file but the user doesn't want to undo all local changes:

if you have one or more files you could apply the same command (git checkout -- file ) to each of those files by listing each of their location separated by space as in:

git checkout -- name1/name2/fileOne.ext nameA/subFolder/fileTwo.ext

mind the space above between name1/name2/fileOne.ext nameA/subFolder/fileTwo.ext

For multiple files in the same folder:

If you happen to need to discard changes for all of the files in a certain directory, use the git checkout as follows:

git checkout -- name1/name2/*

The asterisk in the above does the trick of undoing all files at that location under name1/name2.

And, similarly the following can undo changes in all files for multiple folders:

git checkout -- name1/name2/* nameA/subFolder/*

again mind the space between name1/name2/* nameA/subFolder/* in the above.

Note: name1, name2, nameA, subFolder - all of these example folder names indicate the folder or package where the file(s) in question may be residing.

moving committed (but not pushed) changes to a new branch after pull

Here is a much simpler way:

  1. Create a new branch

  2. On your new branch do a git merge master- this will merge your committed (not pushed) changes to your new branch

  3. Delete you local master branch git branch -D master Use -D instead of -d because you want to force delete the branch.

  4. Just do a git fetch on your master branch and do a git pull on your master branch to ensure you have your teams latest code.

mysql SELECT IF statement with OR

Presumably this would work:

IF(compliment = 'set' OR compliment = 'Y' OR compliment = 1, 'Y', 'N') AS customer_compliment

The type is defined in an assembly that is not referenced, how to find the cause?

It didn't work for me when I've tried to add the reference from the .NET Assemblies tab. It worked, though, when I've added the reference with BROWSE to C:\Windows\Microsoft.NET\Framework\v4.0.30319

What does #defining WIN32_LEAN_AND_MEAN exclude exactly?

According the to Windows Dev Center WIN32_LEAN_AND_MEAN excludes APIs such as Cryptography, DDE, RPC, Shell, and Windows Sockets.

The term "Add-Migration" is not recognized

same issue...resolved by dong the following

1.) close pm manager 2.) close Visual Studio 3.) Open Visual Studio 4.) Open pm manager

seems the trick is to close PM Manager before closing VS

Oracle - Insert New Row with Auto Incremental ID

SQL trigger for automatic date generation in oracle table:

CREATE OR REPLACE TRIGGER name_of_trigger

BEFORE INSERT

ON table_name

REFERENCING NEW AS NEW

FOR EACH ROW

BEGIN

SELECT sysdate INTO :NEW.column_name FROM dual;

END;

/

Find which rows have different values for a given column in Teradata SQL

Join the table with itself and give it two different aliases (A and B in the following example). This allows to compare different rows of the same table.

SELECT DISTINCT A.Id
FROM
    Address A
    INNER JOIN Address B
        ON A.Id = B.Id AND A.[Adress Code] < B.[Adress Code]
WHERE
    A.Address <> B.Address

The "less than" comparison < ensures that you get 2 different addresses and you don't get the same 2 address codes twice. Using "not equal" <> instead, would yield the codes as (1, 2) and (2, 1); each one of them for the A alias and the B alias in turn.

The join clause is responsible for the pairing of the rows where as the where-clause tests additional conditions.


The query above works with any address codes. If you want to compare addresses with specific address codes, you can change the query to

SELECT A.Id
FROM
    Address A
    INNER JOIN Address B
        ON A.Id = B.Id
WHERE                     
    A.[Adress Code] = 1 AND
    B.[Adress Code] = 2 AND
    A.Address <> B.Address

I imagine that this might be useful to find customers having a billing address (Adress Code = 1 as an example) differing from the delivery address (Adress Code = 2) .

Get protocol, domain, and port from URL

first get the current address

var url = window.location.href

Then just parse that string

var arr = url.split("/");

your url is:

var result = arr[0] + "//" + arr[2]

Hope this helps

How do I deal with "signed/unsigned mismatch" warnings (C4018)?

I will give you a better idea

for(decltype(things.size()) i = 0; i < things.size(); i++){
                   //...
}

decltype is

Inspects the declared type of an entity or the type and value category of an expression.

So, It deduces type of things.size() and i will be a type as same as things.size(). So, i < things.size() will be executed without any warning

How to install XCODE in windows 7 platform?

X-code is primarily made for OS-X or iPhone development on Mac systems. Versions for Windows are not available. However this might help!

There is no way to get Xcode on Windows; however you can use a different SDK like Corona instead although it will not use Objective-C (I believe it uses Lua). I have however heard that it is horrible to use.

Source: classroomm.com

Convert NSData to String?

Objective-C

You can use (see NSString Class Reference)

- (id)initWithData:(NSData *)data encoding:(NSStringEncoding)encoding

Example:

NSString *myString = [[NSString alloc] initWithData:myData encoding:NSUTF8StringEncoding];

Remark: Please notice the NSData value must be valid for the encoding specified (UTF-8 in the example above), otherwise nil will be returned:

Returns nil if the initialization fails for some reason (for example if data does not represent valid data for encoding).

Prior Swift 3.0

String(data: yourData, encoding: NSUTF8StringEncoding)

Swift 3.0 Onwards

String(data: yourData, encoding: .utf8)

See String#init(data:encoding:) Reference

ssl_error_rx_record_too_long and Apache SSL

My problem was due to a LOW MTU over a VPN connection.

netsh interface ipv4 show inter

Idx  Met   MTU   State        Name
---  ---  -----  -----------  -------------------
  1 4275 4294967295  connected    Loopback Pseudo-Interface 1
 10 4250   **1300**  connected    Wireless Network Connection
 31   25   1400  connected    Remote Access to XYZ Network

Fix: netsh interface ipv4 set interface "Wireless Network Connection" mtu=1400

It may be an issue over a non-VPN connection also...

Convert javascript array to string

I needed an array to became a String rappresentation of an array I mean I needed that

var a = ['a','b','c'];
//became a "real" array string-like to pass on query params so was easy to do:
JSON.stringify(a); //-->"['a','b','c']"

maybe someone need it :)

how does Request.QueryString work?

The HttpRequest class represents the request made to the server and has various properties associated with it, such as QueryString.

The ASP.NET run-time parses a request to the server and populates this information for you.

Read HttpRequest Properties for a list of all the potential properties that get populated on you behalf by ASP.NET.

Note: not all properties will be populated, for instance if your request has no query string, then the QueryString will be null/empty. So you should check to see if what you expect to be in the query string is actually there before using it like this:

if (!String.IsNullOrEmpty(Request.QueryString["pID"]))
{
    // Query string value is there so now use it
    int thePID = Convert.ToInt32(Request.QueryString["pID"]);
}

How do I upload a file with metadata using a REST web service?

To build on ccleve's answer, if you are using superagent / express / multer, on the front end side build your multipart request doing something like this:

superagent
    .post(url)
    .accept('application/json')
    .field('myVeryRelevantJsonData', JSON.stringify({ peep: 'Peep Peep!!!' }))
    .attach('myFile', file);

cf https://visionmedia.github.io/superagent/#multipart-requests.

On the express side, whatever was passed as field will end up in req.body after doing:

app.use(express.json({ limit: '3MB' }));

Your route would include something like this:

const multerMemStorage = multer.memoryStorage();
const multerUploadToMem = multer({
  storage: multerMemStorage,
  // Also specify fileFilter, limits...
});

router.post('/myUploads',
  multerUploadToMem.single('myFile'),
  async (req, res, next) => {
    // Find back myVeryRelevantJsonData :
    logger.verbose(`Uploaded req.body=${JSON.stringify(req.body)}`);

    // If your file is text:
    const newFileText = req.file.buffer.toString();
    logger.verbose(`Uploaded text=${newFileText}`);
    return next();
  },
  ...

One thing to keep in mind though is this note from the multer doc, concerning disk storage:

Note that req.body might not have been fully populated yet. It depends on the order that the client transmits fields and files to the server.

I guess this means it would be unreliable to, say, compute the target dir/filename based on json metadata passed along the file

Remove characters before character "."

A couple of methods that, if the char does not exists, return the original string.

This one cuts the string after the first occurrence of the pivot:

public static string truncateStringAfterChar(string input, char pivot){         
    int index = input.IndexOf(pivot);   
    if(index >= 0) {
        return input.Substring(index + 1);          
    }           
    return input;       
}

This one instead cuts the string after the last occurrence of the pivot:

public static string truncateStringAfterLastChar(string input, char pivot){         
    return input.Split(pivot).Last();   
}

Custom li list-style with font-awesome icon

I did it like this:

li {
  list-style: none;
  background-image: url("./assets/img/control.svg");
  background-repeat: no-repeat;
  background-position: left center;
}

Or you can try this if you want to change the color:

li::before {
  content: "";
  display: inline-block;
  height: 10px;
  width: 10px;
  margin-right: 7px;

  background-color: orange;
  -webkit-mask-image: url("./assets/img/control.svg");
  -webkit-mask-size: cover;
}

How to run console application from Windows Service?

Starting from Windows Vista, a service cannot interact with the desktop. You will not be able to see any windows or console windows that are started from a service. See this MSDN forum thread.

On other OS, there is an option that is available in the service option called "Allow Service to interact with desktop". Technically, you should program for the future and should follow the Vista guideline even if you don't use it on Vista.

If you still want to run an application that never interact with the desktop, try specifying the process to not use the shell.

ProcessStartInfo info = new ProcessStartInfo(@"c:\myprogram.exe");
info.UseShellExecute = false;
info.RedirectStandardError = true;
info.RedirectStandardInput = true;
info.RedirectStandardOutput = true;
info.CreateNoWindow = true;
info.ErrorDialog = false;
info.WindowStyle = ProcessWindowStyle.Hidden;

Process process = Process.Start(info);

See if this does the trick.

First you inform Windows that the program won't use the shell (which is inaccessible in Vista to service).

Secondly, you redirect all consoles interaction to internal stream (see process.StandardInput and process.StandardOutput.

Duplicate AssemblyVersion Attribute

Starting from Visual Studio 2017 another solution to keep using the AssemblyInfo.cs file is to turn off automatic assembly info generation like this:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <GenerateAssemblyInfo>false</GenerateAssemblyInfo>
  </PropertyGroup>
</Project>

I personally find it very useful for projects which need to support both .NET Framework and .NET Standard.

How to generate javadoc comments in Android Studio

Here we can some something like this. And instead of using any shortcut we can write "default" comments at class/ package /project level. And modify as per requirement

   *** Install JavaDoc Plugin ***



     1.Press shift twice and  Go to Plugins.
     2. search for JavaDocs plugin
     3. Install it. 
     4. Restart Android Studio.
     5. Now, rightclick on Java file/package and goto 
        JavaDocs >> create javadocs for all elements
        It will  generate all default comments.

Advantage is that, you can create comment block for all the methods at a time.

How do I declare an array variable in VBA?

Further to RolandTumble's answer to Cody Gray's answer, both fine answers, here is another very simple and flexible way, when you know all of the array contents at coding time - e.g. you just want to build an array that contains 1, 10, 20 and 50. This also uses variant declaration, but doesn't use ReDim. Like in Roland's answer, the enumerated count of the number of array elements need not be specifically known, but is obtainable by using uBound.

sub Demo_array()
    Dim MyArray as Variant, MyArray2 as Variant, i as Long

    MyArray = Array(1, 10, 20, 50)  'The key - the powerful Array() statement
    MyArray2 = Array("Apple", "Pear", "Orange") 'strings work too

    For i = 0 to UBound(MyArray)
        Debug.Print i, MyArray(i)
    Next i
    For i = 0 to UBound(MyArray2)
        Debug.Print i, MyArray2(i)
    Next i
End Sub

I love this more than any of the other ways to create arrays. What's great is that you can add or subtract members of the array right there in the Array statement, and nothing else need be done to code. To add Egg to your 3 element food array, you just type

, "Egg"

in the appropriate place, and you're done. Your food array now has the 4 elements, and nothing had to be modified in the Dim, and ReDim is omitted entirely.

If a 0-based array is not desired - i.e., using MyArray(0) - one solution is just to jam a 0 or "" for that first element.

Note, this might be regarded badly by some coding purists; one fair objection would be that "hard data" should be in Const statements, not code statements in routines. Another beef might be that, if you stick 36 elements into an array, you should set a const to 36, rather than code in ignorance of that. The latter objection is debatable, because it imposes a requirement to maintain the Const with 36 rather than relying on uBound. If you add a 37th element but leave the Const at 36, trouble is possible.

Why are primes important in cryptography?

It's not so much the prime numbers themselves that are important, but the algorithms that work with primes. In particular, finding the factors of a number (any number).

As you know, any number has at least two factors. Prime numbers have the unique property in that they have exactly two factors: 1 and themselves.

The reason factoring is so important is mathematicians and computer scientists don't know how to factor a number without simply trying every possible combination. That is, first try dividing by 2, then by 3, then by 4, and so forth. If you try to factor a prime number--especially a very large one--you'll have to try (essentially) every possible number between 2 and that large prime number. Even on the fastest computers, it will take years (even centuries) to factor the kinds of prime numbers used in cryptography.

It is the fact that we don't know how to efficiently factor a large number that gives cryptographic algorithms their strength. If, one day, someone figures out how to do it, all the cryptographic algorithms we currently use will become obsolete. This remains an open area of research.

Android Service needs to run always (Never pause or stop)

You can implement startForeground for the service and even if it dies you can restart it by using START_STICKY on startCommand(). Not sure though this is the right implementation.

How to set shadows in React Native for android?

The following will help you to give each Platform the styling you want:

import { Text, View, Platform } from 'react-native';

......
<View style={styles.viewClass}></View>
......


const styles = {
viewClass: {
    justifyContent: 'center',
    alignItems: 'center',
    height: 60,
    ...Platform.select({
        ios: {
            shadowColor: '#000',
            shadowOffset: { width: 0, height: 2 },
            shadowOpacity: 0.2,
        },
        android: {
            elevation: 1

        },
      }),
}
};

How to access the php.ini from my CPanel?

If you're on a shared hosting environment you won't have access to the php.ini to make these changes, if you need access, a virtual private server (VPS) or a dedicated server may be a better option if you're confident in managing it yourself.

Alternatively if you create a new file called .htaccess in your root of your web directory (Ensure it doesn't contain a .txt extension if using notepad to create the file) and copy something like this inside.

php_value settingToChange 6000

This will only work if your hosting provider let's you override the certain config value. Best to ask if it doesn't work after trying.

Even though JRE 8 is installed on my MAC -" No Java Runtime present,requesting to install " gets displayed in terminal

Since it sounds like your JAVA_HOME variable is not set correctly, follow the instructions for setting that.

Setting JAVA_HOME environment variable on MAC OSX 10.9

I would imagine once you set this, it will stop complaining.

How to use the "required" attribute with a "radio" input field

I had to use required="required" along with the same name and type, and then validation worked fine.

<input type="radio" name="user-radio"  id="" value="User" required="required" />

<input type="radio" name="user-radio" id="" value="Admin" />

<input type="radio" name="user-radio" id="" value="Guest" /> 

In practice, what are the main uses for the new "yield from" syntax in Python 3.3?

In applied usage for the Asynchronous IO coroutine, yield from has a similar behavior as await in a coroutine function. Both of which is used to suspend the execution of coroutine.

For Asyncio, if there's no need to support an older Python version (i.e. >3.5), async def/await is the recommended syntax to define a coroutine. Thus yield from is no longer needed in a coroutine.

But in general outside of asyncio, yield from <sub-generator> has still some other usage in iterating the sub-generator as mentioned in the earlier answer.

Spring Data JPA findOne() change to Optional how to use this?

From at least, the 2.0 version, Spring-Data-Jpa modified findOne().
Now, findOne() has neither the same signature nor the same behavior.
Previously, it was defined in the CrudRepository interface as:

T findOne(ID primaryKey);

Now, the single findOne() method that you will find in CrudRepository is the one defined in the QueryByExampleExecutor interface as:

<S extends T> Optional<S> findOne(Example<S> example);

That is implemented finally by SimpleJpaRepository, the default implementation of the CrudRepository interface.
This method is a query by example search and you don't want that as a replacement.

In fact, the method with the same behavior is still there in the new API, but the method name has changed.
It was renamed from findOne() to findById() in the CrudRepository interface :

Optional<T> findById(ID id); 

Now it returns an Optional, which is not so bad to prevent NullPointerException.

So, the actual method to invoke is now Optional<T> findById(ID id).

How to use that?
Learning Optional usage. Here's important information about its specification:

A container object which may or may not contain a non-null value. If a value is present, isPresent() will return true and get() will return the value.

Additional methods that depend on the presence or absence of a contained value are provided, such as orElse() (return a default value if value not present) and ifPresent() (execute a block of code if the value is present).


Some hints on how to use Optional with Optional<T> findById(ID id).

Generally, as you look for an entity by id, you want to return it or make a particular processing if that is not retrieved.

Here are three classical usage examples.

  1. Suppose that if the entity is found you want to get it otherwise you want to get a default value.

You could write :

Foo foo = repository.findById(id)
                    .orElse(new Foo());

or get a null default value if it makes sense (same behavior as before the API change) :

Foo foo = repository.findById(id)
                    .orElse(null);
  1. Suppose that if the entity is found you want to return it, else you want to throw an exception.

You could write :

return repository.findById(id)
        .orElseThrow(() -> new EntityNotFoundException(id));
  1. Suppose you want to apply a different processing according to if the entity is found or not (without necessarily throwing an exception).

You could write :

Optional<Foo> fooOptional = fooRepository.findById(id);
if (fooOptional.isPresent()) {
    Foo foo = fooOptional.get();
    // processing with foo ...
} else {
    // alternative processing....
}

Property 'value' does not exist on type EventTarget in TypeScript

you can also create your own interface as well.

    export interface UserEvent {
      target: HTMLInputElement;
    }

       ...

    onUpdatingServerName(event: UserEvent) {
      .....
    }

Simple insecure two-way data "obfuscation"?

The namespace System.Security.Cryptography contains the TripleDESCryptoServiceProvider and RijndaelManaged classes

Don't forget to add a reference to the System.Security assembly.

How can I tell if a Java integer is null?

parseInt() is just going to throw an exception if the parsing can't complete successfully. You can instead use Integers, the corresponding object type, which makes things a little bit cleaner. So you probably want something closer to:

Integer s = null;

try { 
  s = Integer.valueOf(startField.getText());
}
catch (NumberFormatException e) {
  // ...
}

if (s != null) { ... }

Beware if you do decide to use parseInt()! parseInt() doesn't support good internationalization, so you have to jump through even more hoops:

try {
    NumberFormat nf = NumberFormat.getIntegerInstance(locale);
    nf.setParseIntegerOnly(true);
    nf.setMaximumIntegerDigits(9); // Or whatever you'd like to max out at.

    // Start parsing from the beginning.
    ParsePosition p = new ParsePosition(0);

    int val = format.parse(str, p).intValue();
    if (p.getIndex() != str.length()) {
        // There's some stuff after all the digits are done being processed.
    }

    // Work with the processed value here.
} catch (java.text.ParseFormatException exc) {
    // Something blew up in the parsing.
}

'React' must be in scope when using JSX react/react-in-jsx-scope?

For those who still don't get the accepted solution :

Add

import React from 'react'
import ReactDOM from 'react-dom'

at the top of the file.

Get Image Height and Width as integer values?

PHP's getimagesize() returns an array of data. The first two items in the array are the two items you're interested in: the width and height. To get these, you would simply request the first two indexes in the returned array:

var $imagedata = getimagesize("someimage.jpg");

print "Image width  is: " . $imagedata[0];
print "Image height is: " . $imagedata[1];

For further information, see the documentation.

Find control by name from Windows Forms controls

You can use:

f.Controls[name];

Where f is your form variable. That gives you the control with name name.

Android get image from gallery into ImageView

I think the simplest way it's to use library ContentManager. This library for getting photo or video from a device gallery, cloud or camera. With asynchronous load from the cloud and fixed bugs for some problem devices.

Download via Gradle: compile 'com.github.stfalcon:contentmanager:0.4.3' You can find documentation at https://github.com/stfalcon-studio/ContentManager

CertificateException: No name matching ssl.someUrl.de found

In case, it helps someone:

Use case: i am using a self-signed certificate for my development on localhost.

Error: Caused by: java.security.cert.CertificateException: No name matching localhost found

Solution: When you generate your self-signed certicate, make sure you answer this question like that(See Bruno's answer for the why):

What is your first and last name?
  [Unknown]:  localhost



As a bonus, here are my steps:
1. Generate self-signed certificate:

keytool -genkeypair -alias netty -storetype PKCS12 -keyalg RSA -keysize 2048 -keystore keystore.p12 -validity 4000
Enter keystore password: ***
Re-enter new password: ***
What is your first and last name?
  [Unknown]:  localhost
...

2. Copy the certificate in src/main/resources(if necessary)

3. Update the cacerts
keytool -v -importkeystore -srckeystore keystore.p12 -srcstoretype pkcs12 -destkeystore "%JAVA_HOME%\jre\lib\security\cacerts" -deststoretype jks

4. Update your config(in my case application.properties):

server.port=8443
server.ssl.key-store=classpath:keystore.p12
server.ssl.key-store-password=jumping_monkey
server.ssl.key-store-type=pkcs12
server.ssl.key-alias=netty



Cheers

cURL POST command line on WINDOWS RESTful service

At least for the Windows binary version I tested, (the Generic Win64 no-SSL binary, currently based on 7.33.0), you are subject to limitations in how the command line arguments are being parsed. The answer by xmas describes the correct syntax in that setting, which also works in a batch file. Using the example provided:

curl -i -X POST -H "Content-Type: application/json" -d "{""data1"":""data goes here"",""data2"":""data2 goes here""}" http:localhost/path/to/api

A cleaner alternative to avoid having to deal with escaped characters, which is dependent upon whatever library is used to parse the command line, is to have your standard json format text in a separate file:

curl -i -X POST -H "Content-Type: application/json" -d "@body.json" http:localhost/path/to/api

git status (nothing to commit, working directory clean), however with changes commited

git status output tells you three things by default:

  1. which branch you are on
  2. What is the status of your local branch in relation to the remote branch
  3. If you have any uncommitted files

When you did git commit , it committed to your local repository, thus #3 shows nothing to commit, however, #2 should show that you need to push or pull if you have setup the tracking branch.

If you find the output of git status verbose and difficult to comprehend, try using git status -sb this is less verbose and will show you clearly if you need to push or pull. In your case, the output would be something like:

master...origin/master [ahead 1]

git status is pretty useful, in the workflow you described do a git status -sb: after touching the file, after adding the file and after committing the file, see the difference in the output, it will give you more clarity on untracked, tracked and committed files.

Update #1
This answer is applicable if there was a misunderstanding in reading the git status output. However, as it was pointed out, in the OPs case, the upstream was not set correctly. For that, Chris Mae's answer is correct.

TypeScript: Creating an empty typed container array

Okay you got the syntax wrong here, correct way to do this is:

var arr: Criminal[] = [];

I'm assuming you are using var so that means declaring it somewhere inside the func(),my suggestion would be use let instead of var.

If declaring it as c class property usse acces modifiers like private, public, protected.

How to move all HTML element children to another parent using JavaScript?

Modern way:

newParent.append(...oldParent.childNodes);
  1. .append is the replacement for .appendChild. The main difference is that it accepts multiple nodes at once and even plain strings, like .append('hello!')
  2. oldParent.childNodes is iterable so it can be spread with ... to become multiple parameters of .append()

Compatibility tables of both (in short: Edge 17+, Safari 10+):

Error: stray '\240' in program

As mentioned in a previous reply, this generally comes when compiling copy pasted code. If you have a bash shell, the following command generally works:

iconv -f utf-8 -t ascii//translit input.c > output.c

How to draw vertical lines on a given plot in matplotlib

If someone wants to add a legend and/or colors to some vertical lines, then use this:


import matplotlib.pyplot as plt

# x coordinates for the lines
xcoords = [0.1, 0.3, 0.5]
# colors for the lines
colors = ['r','k','b']

for xc,c in zip(xcoords,colors):
    plt.axvline(x=xc, label='line at x = {}'.format(xc), c=c)

plt.legend()
plt.show()

Results:

my amazing plot seralouk

changing default x range in histogram matplotlib

import matplotlib.pyplot as plt


...


plt.xlim(xmin=6.5, xmax = 12.5)

Apply function to each element of a list

I think you mean to use map instead of filter:

>>> from string import upper
>>> mylis=['this is test', 'another test']
>>> map(upper, mylis)
['THIS IS TEST', 'ANOTHER TEST']

Even simpler, you could use str.upper instead of importing from string (thanks to @alecxe):

>>> map(str.upper, mylis)
['THIS IS TEST', 'ANOTHER TEST']

In Python 2.x, map constructs a new list by applying a given function to every element in a list. filter constructs a new list by restricting to elements that evaluate to True with a given function.

In Python 3.x, map and filter construct iterators instead of lists, so if you are using Python 3.x and require a list the list comprehension approach would be better suited.

How to picture "for" loop in block representation of algorithm

The Algorithm for given flow chart :

enter image description here

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

Step :01

  • Start

Step :02 [Variable initialization]

  • Set counter: i<----K [Where K:Positive Number]

Step :03[Condition Check]

  • If condition True then Do your task, set i=i+N and go to Step :03 [Where N:Positive Number]
  • If condition False then go to Step :04

Step:04

  • Stop

What is a lambda (function)?

I like the explanation of Lambdas in this article: The Evolution Of LINQ And Its Impact On The Design Of C#. It made a lot of sense to me as it shows a real world for Lambdas and builds it out as a practical example.

Their quick explanation: Lambdas are a way to treat code (functions) as data.

disable textbox using jquery?

Sorry for being so late at the party, but I see some room for improvement here. Not concerning "disable textbox", but to the radionbox selection and code simplification, making it a bit more future proof, for later changes.

First of all, you shouldn't use .each() and use the index to point out a specific radio button. If you work with a dynamic set of radio buttons or if you add or remove some radio buttons afterwards, then your code will react on the wrong button!

Next, but that wasn't probably the case when the OP was made, I prefer to use .on('click', function(){...}) instead of click... http://api.jquery.com/on/

Lst but not least, also the code could be made more simple and future proof by selecting the radio button based on it's name (but that appeared already in a post).

So I ended up with the following code.

HTML (based on code of o.k.w)

<span id="radiobutt">
    <input type="radio" name="rad1" value="1" />
    <input type="radio" name="rad1" value="2" />
    <input type="radio" name="rad1" value="3" />
</span>
<div>
    <input type="text" id="textbox1" />
    <input type="checkbox" id="checkbox1" />
</div>

JS-code

$("[name='rad1']").on('click', function() {
    var disable = $(this).val() === "2";
    $("#textbox1").prop("disabled", disable); 
    $("#checkbox1").prop("disabled", disable); 
});

What does %~d0 mean in a Windows batch file?

Some gotchas to watch out for:

If you double-click the batch file %0 will be surrounded by quotes. For example, if you save this file as c:\test.bat:

@echo %0
@pause

Double-clicking it will open a new command prompt with output:

"C:\test.bat"

But if you first open a command prompt and call it directly from that command prompt, %0 will refer to whatever you've typed. If you type test.batEnter, the output of %0 will have no quotes because you typed no quotes:

c:\>test.bat
test.bat

If you type testEnter, the output of %0 will have no extension too, because you typed no extension:

c:\>test
test

Same for tEsTEnter:

c:\>tEsT
tEsT

If you type "test"Enter, the output of %0 will have quotes (since you typed them) but no extension:

c:\>"test"
"test"

Lastly, if you type "C:\test.bat", the output would be exactly as though you've double clicked it:

c:\>"C:\test.bat"
"C:\test.bat"

Note that these are not all the possible values %0 can be because you can call the script from other folders:

c:\some_folder>/../teST.bAt
/../teST.bAt

All the examples shown above will also affect %~0, because the output of %~0 is simply the output of %0 minus quotes (if any).

How to change Elasticsearch max memory size

In elasticsearch 2.x :

vi /etc/sysconfig/elasticsearch 

Go to the block of code

# Heap size defaults to 256m min, 1g max
# Set ES_HEAP_SIZE to 50% of available RAM, but no more than 31g
#ES_HEAP_SIZE=2g

Uncomment last line like

ES_HEAP_SIZE=2g

Escaping double quotes in JavaScript onClick event handler

You may also want to try two backslashes (\\") to escape the escape character.

Getting all names in an enum as a String[]

I would write it like this

public static String[] names() {

    java.util.LinkedList<String> list = new LinkedList<String>();
    for (State s : State.values()) {
        list.add(s.name());
    }

    return list.toArray(new String[list.size()]);
}

SQL: Two select statements in one query

The UNION statement is your friend:

SELECT   a.playername, a.games, a.goals
FROM     tblMadrid as a
WHERE    a.playername = "ronaldo"
UNION
SELECT   b.playername, b.games, b.goals
FROM     tblBarcelona as b
WHERE    b.playername = "messi"
ORDER BY goals;

Values of disabled inputs will not be submitted

Disabled controls cannot be successful, and a successful control is "valid" for submission. This is the reason why disabled controls don't submit with the form.

Oracle Error ORA-06512

I also had the same error. In my case reason was I have created a update trigger on a table and under that trigger I am again updating the same table. And when I have removed the update statement from the trigger my problem has been resolved.

What are the differences between NP, NP-Complete and NP-Hard?

I've been looking around and seeing many long explanations. Here is a small chart that may be useful to summarise:

Notice how difficulty increases top to bottom: any NP can be reduced to NP-Complete, and any NP-Complete can be reduced to NP-Hard, all in P (polynomial) time.

If you can solve a more difficult class of problem in P time, that will mean you found how to solve all easier problems in P time (for example, proving P = NP, if you figure out how to solve any NP-Complete problem in P time).

____________________________________________________________
| Problem Type | Verifiable in P time | Solvable in P time | Increasing Difficulty
___________________________________________________________|           |
| P            |        Yes           |        Yes         |           |
| NP           |        Yes           |     Yes or No *    |           |
| NP-Complete  |        Yes           |      Unknown       |           |
| NP-Hard      |     Yes or No **     |      Unknown ***   |           |
____________________________________________________________           V

Notes on Yes or No entries:

  • * An NP problem that is also P is solvable in P time.
  • ** An NP-Hard problem that is also NP-Complete is verifiable in P time.
  • *** NP-Complete problems (all of which form a subset of NP-hard) might be. The rest of NP hard is not.

I also found this diagram quite useful in seeing how all these types correspond to each other (pay more attention to the left half of the diagram).

How can I run code on a background thread on Android?

Today I was looking for this and Mr Brandon Rude gave an excellent answer. Unfortunately, AsyncTask is now depricated, you can still use it, but it gives you a warning which is very annoying. So an alternative is to use Executors like this way (in kotlin):


    val someRunnable = object : Runnable{
      override fun run() {
        // todo: do your background tasks
        requireActivity().runOnUiThread{
          // update views / ui if you are in a fragment
        };
        /*
        runOnUiThread {
          // update ui if you are in an activity
        }
        * */
      }
    };
    Executors.newSingleThreadExecutor().execute(someRunnable);

And in java it looks like this:


        Runnable someRunnable = new Runnable() {
            @Override
            public void run() {
                // todo: background tasks
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        // todo: update your ui / view in activity
                    }
                });

                /*
                requireActivity().runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        // todo: update your ui / view in Fragment
                    }
                });*/
            }
        };

        Executors.newSingleThreadExecutor().execute(someRunnable);

Dynamically changing font size of UILabel

This solution works for multiline:

After following several articles, and requiring a function that would automatically scale the text and adjust the line count to best fit within the given label size, I wrote a function myself. (ie. a short string would fit nicely on one line and use a large amount of the label frame, whereas a long strong would automatically split onto 2 or 3 lines and adjust the size accordingly)

Feel free to re-use it and tweak as required. Make sure you call it after viewDidLayoutSubviews has finished so that the initial label frame has been set.

+ (void)setFontForLabel:(UILabel *)label withMaximumFontSize:(float)maxFontSize andMaximumLines:(int)maxLines {
    int numLines = 1;
    float fontSize = maxFontSize;
    CGSize textSize; // The size of the text
    CGSize frameSize; // The size of the frame of the label
    CGSize unrestrictedFrameSize; // The size the text would be if it were not restricted by the label height
    CGRect originalLabelFrame = label.frame;

    frameSize = label.frame.size;
    textSize = [label.text sizeWithAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize: fontSize]}];

    // Work out the number of lines that will need to fit the text in snug
    while (((textSize.width / numLines) / (textSize.height * numLines) > frameSize.width / frameSize.height) && (numLines < maxLines)) {
        numLines++;
    }

    label.numberOfLines = numLines;

    // Get the current text size
    label.font = [UIFont systemFontOfSize:fontSize];
    textSize = [label.text boundingRectWithSize:CGSizeMake(frameSize.width, CGFLOAT_MAX)
                                        options:(NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading)
                                     attributes:@{NSFontAttributeName : label.font}
                                        context:nil].size;

    // Adjust the frame size so that it can fit text on more lines
    // so that we do not end up with truncated text
    label.frame = CGRectMake(label.frame.origin.x, label.frame.origin.y, label.frame.size.width, label.frame.size.width);

    // Get the size of the text as it would fit into the extended label size
    unrestrictedFrameSize = [label textRectForBounds:CGRectMake(0, 0, label.bounds.size.width, CGFLOAT_MAX) limitedToNumberOfLines:numLines].size;

    // Keep reducing the font size until it fits
    while (textSize.width > unrestrictedFrameSize.width || textSize.height > frameSize.height) {
        fontSize--;
        label.font = [UIFont systemFontOfSize:fontSize];
        textSize = [label.text boundingRectWithSize:CGSizeMake(frameSize.width, CGFLOAT_MAX)
                                            options:(NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading)
                                         attributes:@{NSFontAttributeName : label.font}
                                            context:nil].size;
        unrestrictedFrameSize = [label textRectForBounds:CGRectMake(0, 0, label.bounds.size.width, CGFLOAT_MAX) limitedToNumberOfLines:numLines].size;
    }

    // Set the label frame size back to original
    label.frame = originalLabelFrame;
}

How to count items in JSON data

import json

json_data = json.dumps({
  "result":[
    {
      "run":[
        {
          "action":"stop"
        },
        {
          "action":"start"
        },
        {
          "action":"start"
        }
      ],
      "find": "true"
    }
  ]
})

item_dict = json.loads(json_data)
print len(item_dict['result'][0]['run'])

Convert it in dict.

How to include *.so library in Android Studio?

Android NDK official hello-libs CMake example

https://github.com/googlesamples/android-ndk/tree/840858984e1bb8a7fab37c1b7c571efbe7d6eb75/hello-libs

Just worked for me on Ubuntu 17.10 host, Android Studio 3, Android SDK 26, so I strongly recommend that you base your project on it.

The shared library is called libgperf, the key code parts are:

  • hello-libs/app/src/main/cpp/CMakeLists.txt:

    // -L
    add_library(lib_gperf SHARED IMPORTED)
    set_target_properties(lib_gperf PROPERTIES IMPORTED_LOCATION
              ${distribution_DIR}/gperf/lib/${ANDROID_ABI}/libgperf.so)
    
    // -I
    target_include_directories(hello-libs PRIVATE
                               ${distribution_DIR}/gperf/include)
    // -lgperf
    target_link_libraries(hello-libs
                          lib_gperf)
    
  • app/build.gradle:

    android {
        sourceSets {
            main {
                // let gradle pack the shared library into apk
                jniLibs.srcDirs = ['../distribution/gperf/lib']
    

    Then, if you look under /data/app on the device, libgperf.so will be there as well.

  • on C++ code, use: #include <gperf.h>

  • header location: hello-libs/distribution/gperf/include/gperf.h

  • lib location: distribution/gperf/lib/arm64-v8a/libgperf.so

  • If you only support some architectures, see: Gradle Build NDK target only ARM

The example git tracks the prebuilt shared libraries, but it also contains the build system to actually build them as well: https://github.com/googlesamples/android-ndk/tree/840858984e1bb8a7fab37c1b7c571efbe7d6eb75/hello-libs/gen-libs

How do I save and restore multiple variables in python?

If you need to save multiple objects, you can simply put them in a single list, or tuple, for instance:

import pickle

# obj0, obj1, obj2 are created here...

# Saving the objects:
with open('objs.pkl', 'w') as f:  # Python 3: open(..., 'wb')
    pickle.dump([obj0, obj1, obj2], f)

# Getting back the objects:
with open('objs.pkl') as f:  # Python 3: open(..., 'rb')
    obj0, obj1, obj2 = pickle.load(f)

If you have a lot of data, you can reduce the file size by passing protocol=-1 to dump(); pickle will then use the best available protocol instead of the default historical (and more backward-compatible) protocol. In this case, the file must be opened in binary mode (wb and rb, respectively).

The binary mode should also be used with Python 3, as its default protocol produces binary (i.e. non-text) data (writing mode 'wb' and reading mode 'rb').

Vue JS mounted()

You can also move mounted out of the Vue instance and make it a function in the top-level scope. This is also a useful trick for server side rendering in Vue.

function init() {
  // Use `this` normally
}

new Vue({
  methods:{
    init
  },
  mounted(){
    init.call(this)
  }
})

Git: How to update/checkout a single file from remote origin master?

It is possible to do (in the deployed repository)

git fetch
git checkout origin/master -- path/to/file

The fetch will download all the recent changes, but it will not put it in your current checked out code (working area).

The checkout will update the working tree with the particular file from the downloaded changes (origin/master).

At least this works for me for those little small typo fixes, where it feels weird to create a branch etc just to change one word in a file.

How to reload current page?

I have solved following this way

import { Router, ActivatedRoute } from '@angular/router';

constructor(private router: Router
          , private activeRoute: ActivatedRoute) {

}
reloadCurrentPage(){
   let currentUrl = this.router.url;
   this.router.navigateByUrl('/', {skipLocationChange: true}).then(() => {
   this.router.navigate([currentUrl]);
   });
 }

'Access denied for user 'root'@'localhost' (using password: NO)'

Make sure the MySQL service is running on your machine, then follow the instructions from MySQL for initially setting up root (search for 'windows' and it will take you to the steps for setting up root):

http://dev.mysql.com/doc/refman/5.1/en/default-privileges.html

Differences between CHMOD 755 vs 750 permissions set

0755 = User:rwx Group:r-x World:r-x

0750 = User:rwx Group:r-x World:--- (i.e. World: no access)

r = read
w = write
x = execute (traverse for directories)

Difference between Key, Primary Key, Unique Key and Index in MySQL

KEY and INDEX are synonyms.

You should add an index when performance measurements and EXPLAIN shows you that the query is inefficient because of a missing index. Adding an index can improve the performance of queries (but it can slow down modifications to the table).

You should use UNIQUE when you want to contrain the values in that column (or columns) to be unique, so that attempts to insert duplicate values result in an error.

A PRIMARY KEY is both a unique constraint and it also implies that the column is NOT NULL. It is used to give an identity to each row. This can be useful for joining with another table via a foreign key constraint. While it is not required for a table to have a PRIMARY KEY it is usually a good idea.

filtering NSArray into a new NSArray in Objective-C

Based on an answer by Clay Bridges, here is an example of filtering using blocks (change yourArray to your array variable name and testFunc to the name of your testing function):

yourArray = [yourArray objectsAtIndexes:[yourArray indexesOfObjectsPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop) {
    return [self testFunc:obj];
}]];

How to add a search box with icon to the navbar in Bootstrap 3?

This is the closest I could get without adding any custom CSS (this I'd already figured as of the time of asking the question; guess I've to stick with this):

Navbar Search Box

And the markup in use:

<form class="navbar-form navbar-left" role="search">
    <div class="form-group">
        <input type="text" class="form-control" placeholder="Search">
    </div>
    <button type="submit" class="btn btn-default">
        <span class="glyphicon glyphicon-search"></span>
    </button>
</form>

PS: Of course, that can be fixed by adding a negative margin-left (-4px) on the button, and removing the border-radius on the sides input and button meet. But the whole point of this question is to get it to work without any custom CSS.

Fixed Navbar Search box

pandas dataframe convert column type to string or categorical

Prior answers focused on nominal data (e.g. unordered). If there is a reason to impose order for an ordinal variable, then one would use:

# Transform to category
df['zipcode_category'] = df['zipcode_category'].astype('category')

# Add ordered category
df['zipcode_ordered'] = df['zipcode_category']

# Setup the ordering
df.zipcode_ordered.cat.set_categories(
    new_categories = [90211, 90210], ordered = True, inplace = True
)

# Output IDs
df['zipcode_ordered_id'] = df.zipcode_ordered.cat.codes
print(df)
#  zipcode_category zipcode_ordered  zipcode_ordered_id
#            90210           90210                   1
#            90211           90211                   0

More details on setting ordered categories can be found at the pandas website:

https://pandas.pydata.org/pandas-docs/stable/user_guide/categorical.html#sorting-and-order

How can I render inline JavaScript with Jade / Pug?

No use script tag only.

Solution with |:

script
  | if (10 == 10) {
  |   alert("working")
  | }

Or with a .:

script.
  if (10 == 10) {
    alert("working")
  }

Change icon-bar (?) color in bootstrap

Dude I know totally how you feel, but don't forget about inline styling. It is almost the super saiyan of the CSS specificity

So it should look something like this for you,

<span class="icon-bar" style="background-color: black !important;">
</span>
<span class="icon-bar" style="background-color: black !important;">
</span>
<span class="icon-bar" style="background-color: black !important;">
</span>

Access to Image from origin 'null' has been blocked by CORS policy

To solve your error I propose this solution: to work on Visual studio code editor and install live server extension in the editor, which allows you to connect to your local server, for me I put the picture in my workspace 127.0.0.1:5500/workspace/data/pict.png and it works!

PyLint "Unable to import" error - how to set PYTHONPATH?

general answer for this question I found on this page PLEASE NOT OPEN, SITE IS BUGED

create .pylintrc and add

[MASTER]
init-hook="from pylint.config import find_pylintrc;
import os, sys; sys.path.append(os.path.dirname(find_pylintrc()))"

Launch Android application without main Activity and start Service on launching application

You said you didn't want to use a translucent Activity, but that seems to be the best way to do this:

  1. In your Manifest, set the Activity theme to Theme.Translucent.NoTitleBar.
  2. Don't bother with a layout for your Activity, and don't call setContentView().
  3. In your Activity's onCreate(), start your Service with startService().
  4. Exit the Activity with finish() once you've started the Service.

In other words, your Activity doesn't have to be visible; it can simply make sure your Service is running and then exit, which sounds like what you want.

I would highly recommend showing at least a Toast notification indicating to the user that you are launching the Service, or that it is already running. It is very bad user experience to have a launcher icon that appears to do nothing when you press it.

The type arguments cannot be inferred from the usage. Try specifying the type arguments explicitly

In case it helps, I've ran into this problem when passing null into a parameter for a generic TValue, to get around this you have to cast your null values:

(string)null

(int)null

etc.

std::wstring VS std::string

string? wstring?

std::string is a basic_string templated on a char, and std::wstring on a wchar_t.

char vs. wchar_t

char is supposed to hold a character, usually an 8-bit character.
wchar_t is supposed to hold a wide character, and then, things get tricky:
On Linux, a wchar_t is 4 bytes, while on Windows, it's 2 bytes.

What about Unicode, then?

The problem is that neither char nor wchar_t is directly tied to unicode.

On Linux?

Let's take a Linux OS: My Ubuntu system is already unicode aware. When I work with a char string, it is natively encoded in UTF-8 (i.e. Unicode string of chars). The following code:

#include <cstring>
#include <iostream>

int main(int argc, char* argv[])
{
   const char text[] = "olé" ;


   std::cout << "sizeof(char)    : " << sizeof(char) << std::endl ;
   std::cout << "text            : " << text << std::endl ;
   std::cout << "sizeof(text)    : " << sizeof(text) << std::endl ;
   std::cout << "strlen(text)    : " << strlen(text) << std::endl ;

   std::cout << "text(ordinals)  :" ;

   for(size_t i = 0, iMax = strlen(text); i < iMax; ++i)
   {
      std::cout << " " << static_cast<unsigned int>(
                              static_cast<unsigned char>(text[i])
                          );
   }

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

   // - - - 

   const wchar_t wtext[] = L"olé" ;

   std::cout << "sizeof(wchar_t) : " << sizeof(wchar_t) << std::endl ;
   //std::cout << "wtext           : " << wtext << std::endl ; <- error
   std::cout << "wtext           : UNABLE TO CONVERT NATIVELY." << std::endl ;
   std::wcout << L"wtext           : " << wtext << std::endl;

   std::cout << "sizeof(wtext)   : " << sizeof(wtext) << std::endl ;
   std::cout << "wcslen(wtext)   : " << wcslen(wtext) << std::endl ;

   std::cout << "wtext(ordinals) :" ;

   for(size_t i = 0, iMax = wcslen(wtext); i < iMax; ++i)
   {
      std::cout << " " << static_cast<unsigned int>(
                              static_cast<unsigned short>(wtext[i])
                              );
   }

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

   return 0;
}

outputs the following text:

sizeof(char)    : 1
text            : olé
sizeof(text)    : 5
strlen(text)    : 4
text(ordinals)  : 111 108 195 169

sizeof(wchar_t) : 4
wtext           : UNABLE TO CONVERT NATIVELY.
wtext           : ol?
sizeof(wtext)   : 16
wcslen(wtext)   : 3
wtext(ordinals) : 111 108 233

You'll see the "olé" text in char is really constructed by four chars: 110, 108, 195 and 169 (not counting the trailing zero). (I'll let you study the wchar_t code as an exercise)

So, when working with a char on Linux, you should usually end up using Unicode without even knowing it. And as std::string works with char, so std::string is already unicode-ready.

Note that std::string, like the C string API, will consider the "olé" string to have 4 characters, not three. So you should be cautious when truncating/playing with unicode chars because some combination of chars is forbidden in UTF-8.

On Windows?

On Windows, this is a bit different. Win32 had to support a lot of application working with char and on different charsets/codepages produced in all the world, before the advent of Unicode.

So their solution was an interesting one: If an application works with char, then the char strings are encoded/printed/shown on GUI labels using the local charset/codepage on the machine. For example, "olé" would be "olé" in a French-localized Windows, but would be something different on an cyrillic-localized Windows ("ol?" if you use Windows-1251). Thus, "historical apps" will usually still work the same old way.

For Unicode based applications, Windows uses wchar_t, which is 2-bytes wide, and is encoded in UTF-16, which is Unicode encoded on 2-bytes characters (or at the very least, the mostly compatible UCS-2, which is almost the same thing IIRC).

Applications using char are said "multibyte" (because each glyph is composed of one or more chars), while applications using wchar_t are said "widechar" (because each glyph is composed of one or two wchar_t. See MultiByteToWideChar and WideCharToMultiByte Win32 conversion API for more info.

Thus, if you work on Windows, you badly want to use wchar_t (unless you use a framework hiding that, like GTK+ or QT...). The fact is that behind the scenes, Windows works with wchar_t strings, so even historical applications will have their char strings converted in wchar_t when using API like SetWindowText() (low level API function to set the label on a Win32 GUI).

Memory issues?

UTF-32 is 4 bytes per characters, so there is no much to add, if only that a UTF-8 text and UTF-16 text will always use less or the same amount of memory than an UTF-32 text (and usually less).

If there is a memory issue, then you should know than for most western languages, UTF-8 text will use less memory than the same UTF-16 one.

Still, for other languages (chinese, japanese, etc.), the memory used will be either the same, or slightly larger for UTF-8 than for UTF-16.

All in all, UTF-16 will mostly use 2 and occassionally 4 bytes per characters (unless you're dealing with some kind of esoteric language glyphs (Klingon? Elvish?), while UTF-8 will spend from 1 to 4 bytes.

See http://en.wikipedia.org/wiki/UTF-8#Compared_to_UTF-16 for more info.

Conclusion

  1. When I should use std::wstring over std::string?

    On Linux? Almost never (§).
    On Windows? Almost always (§).
    On cross-platform code? Depends on your toolkit...

    (§) : unless you use a toolkit/framework saying otherwise

  2. Can std::string hold all the ASCII character set including special characters?

    Notice: A std::string is suitable for holding a 'binary' buffer, where a std::wstring is not!

    On Linux? Yes.
    On Windows? Only special characters available for the current locale of the Windows user.

    Edit (After a comment from Johann Gerell):
    a std::string will be enough to handle all char-based strings (each char being a number from 0 to 255). But:

    1. ASCII is supposed to go from 0 to 127. Higher chars are NOT ASCII.
    2. a char from 0 to 127 will be held correctly
    3. a char from 128 to 255 will have a signification depending on your encoding (unicode, non-unicode, etc.), but it will be able to hold all Unicode glyphs as long as they are encoded in UTF-8.
  3. Is std::wstring supported by almost all popular C++ compilers?

    Mostly, with the exception of GCC based compilers that are ported to Windows.
    It works on my g++ 4.3.2 (under Linux), and I used Unicode API on Win32 since Visual C++ 6.

  4. What is exactly a wide character?

    On C/C++, it's a character type written wchar_t which is larger than the simple char character type. It is supposed to be used to put inside characters whose indices (like Unicode glyphs) are larger than 255 (or 127, depending...).

How to create JSON post to api using C#

Try using Web API HttpClient

    static async Task RunAsync()
    {
        using (var client = new HttpClient())
        {
            client.BaseAddress = new Uri("http://domain.com/");
            client.DefaultRequestHeaders.Accept.Clear();
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));


            // HTTP POST
            var obj = new MyObject() { Str = "MyString"};
            response = await client.PostAsJsonAsync("POST URL GOES HERE?", obj );
            if (response.IsSuccessStatusCode)
            {
                response.//.. Contains the returned content.
            }
        }
    }

You can find more details here Web API Clients

Calling another method java GUI

I'm not sure what you're trying to do, but here's something to consider: c(); won't do anything. c is an instance of the class checkbox and not a method to be called. So consider this:

public class FirstWindow extends JFrame {      public FirstWindow() {         checkbox c = new checkbox();         c.yourMethod(yourParameters); // call the method you made in checkbox     } }  public class checkbox extends JFrame {      public checkbox(yourParameters) {          // this is the constructor method used to initialize instance variables     }      public void yourMethod() // doesn't have to be void     {         // put your code here     } } 

How to set editable true/false EditText in Android programmatically?

Try this it is working fine for me..

EditText.setInputType(0);
EditText.setFilters(new InputFilter[] {new InputFilter()
{
@Override
public CharSequence filter(CharSequence source, int start,
                            int end, Spanned dest, int dstart, int dend) 
{
return source.length() < 1 ? dest.subSequence(dstart, dend) : "";

}
}
});

Obtain form input fields using jQuery?

serialize() is the best method. @ Christopher Parker say that Nickf's anwser accomplishes more, however it does not take into account that the form may contain textarea and select menus. It is far better to use serialize() and then manipulate that as you need to. Data from serialize() can be used in either an Ajax post or get, so there is no issue there.

Get current date in Swift 3?

You can do it in this way with Swift 3.0:

let date = Date()
let calendar = Calendar.current
let components = calendar.dateComponents([.year, .month, .day], from: date)

let year =  components.year
let month = components.month
let day = components.day

print(year)
print(month)
print(day)

Python: printing a file to stdout

If it's a large file and you don't want to consume a ton of memory as might happen with Ben's solution, the extra code in

>>> import shutil
>>> import sys
>>> with open("test.txt", "r") as f:
...    shutil.copyfileobj(f, sys.stdout)

also works.

Batch program to to check if process exists

This is a one line solution.

It will run taskkill only if the process is really running otherwise it will just info that it is not running.

tasklist | find /i "notepad.exe" && taskkill /im notepad.exe /F || echo process "notepad.exe" not running.

This is the output in case the process was running:

notepad.exe           1960 Console                   0    112,260 K
SUCCESS: The process "notepad.exe" with PID 1960 has been terminated.

This is the output in case not running:

process "notepad.exe" not running.

jQuery date formatting

You could make use of this snippet

_x000D_
_x000D_
$('.datepicker').datepicker({_x000D_
  changeMonth: true,_x000D_
  changeYear: true,_x000D_
  yearRange: '1900:+0',_x000D_
  defaultDate: '01 JAN 1900',_x000D_
  buttonImage: "http://www.theplazaclub.com/club/images/calendar/outlook_calendar.gif",_x000D_
  dateFormat: 'dd/mm/yy',_x000D_
  onSelect: function() {_x000D_
    $('#datepicker').val($(this).datepicker({_x000D_
      dateFormat: 'dd/mm/yy'_x000D_
    }).val());_x000D_
  }_x000D_
});
_x000D_
<link rel="stylesheet" href="//code.jquery.com/ui/1.11.4/themes/smoothness/jquery-ui.css">_x000D_
<script src="//code.jquery.com/jquery-1.10.2.js"></script>_x000D_
<script src="//code.jquery.com/ui/1.11.4/jquery-ui.js"></script>_x000D_
_x000D_
<p>_x000D_
  selector: <input type="text" class="datepicker">_x000D_
</p>_x000D_
<p>_x000D_
  output: <input type="text" id="datepicker">_x000D_
</p>
_x000D_
_x000D_
_x000D_

Get second child using jQuery

In addition to using jQuery methods, you can use the native cells collection that the <tr> gives you.

$(t)[0].cells[1].innerHTML

Assuming t is a DOM element, you could bypass the jQuery object creation.

t.cells[1].innerHTML

How to track down access violation "at address 00000000"

The accepted answer does not tell the entire story.

Yes, whenever you see zeros, a NULL pointer is involved. That is because NULL is by definition zero. So calling zero NULL may not be saying much.

What is interesting about the message you get is the fact that NULL is mentioned twice. In fact, the message you report looks a little bit like the messages Windows-brand operating systems show the user.

The message says the address NULL tried to read NULL. So what does that mean? Specifically, how does an address read itself?

We typically think of the instructions at an address reading and writing from memory at certain addresses. Knowing that allows us to parse the error message. The message is trying to articulate that the instruction at address NULL tried to read NULL.

Of course, there is no instruction at address NULL, that is why we think of NULL as special in our code. But every instruction can be thought of as commencing with the attempt to read itself. If the CPUs EIP register is at address NULL, then the CPU will attempt to read the opcode for an instruction from address 0x00000000 (NULL). This attempt to read NULL will fail, and generate the message you have received.

In the debugger, notice that EIP equals 0x00000000 when you receive this message. This confirms the description I have given you.

The question then becomes, "why does my program attempt to execute the NULL address." There are three possibilities which spring to mind:

  • You have attempt to make a function call via a function pointer which you have declared, assigned to NULL, never initialized otherwise, and are dereferencing.
  • Similarly, you may be calling an "abstract" C++ method which has a NULL entry in the object's vtable. These are created in your code with the syntax virtual function_name()=0.
  • In your code, a stack buffer has been overflowed while writing zeros. The zeros have been written beyond the end of the stack buffer, over the preserved return address. When the function later executes its ret instruction, the value 0x00000000 (NULL) is loaded from the overwritten memory spot. This type of error, stack overflow, is the eponym of our forum.

Since you mention that you are calling a third-party library, I will point out that it may be a situation of the library expecting you to provide a non-NULL function pointer as input to some API. These are sometimes known as "call back" functions.

You will have to use the debugger to narrow down the cause of your problem further, but the above possiblities should help you solve the riddle.

Exporting data In SQL Server as INSERT INTO

If you are running SQL Server 2008 R2 the built in options on to do this in SSMS as marc_s described above changed a bit. Instead of selecting Script data = true as shown in his diagram, there is now a new option called "Types of data to script" just above the "Table/View Options" grouping. Here you can select to script data only, schema and data or schema only. Works like a charm.

How can I access and process nested objects, arrays or JSON?

Just in case, anyone's visiting this question in 2017 or later and looking for an easy-to-remember way, here's an elaborate blog post on Accessing Nested Objects in JavaScript without being bamboozled by

Cannot read property 'foo' of undefined error

1. Oliver Steele's nested object access pattern

The easiest and the cleanest way is to use Oliver Steele's nested object access pattern

const name = ((user || {}).personalInfo || {}).name;

With this notation, you'll never run into

Cannot read property 'name' of undefined.

You basically check if user exists, if not, you create an empty object on the fly. This way, the next level key will always be accessed from an object that exists or an empty object, but never from undefined.

2. Access Nested Objects Using Array Reduce

To be able to access nested arrays, you can write your own array reduce util.

const getNestedObject = (nestedObj, pathArr) => {
    return pathArr.reduce((obj, key) =>
        (obj && obj[key] !== 'undefined') ? obj[key] : undefined, nestedObj);
}

// pass in your object structure as array elements
const name = getNestedObject(user, ['personalInfo', 'name']);

// to access nested array, just pass in array index as an element the path array.
const city = getNestedObject(user, ['personalInfo', 'addresses', 0, 'city']);
// this will return the city from the first address item.

There is also an excellent type handling minimal library typy that does all this for you.

Re-assign host access permission to MySQL user

I received the same error with RENAME USER and GRANTS aren't covered by the currently accepted solution:

The most reliable way seems to be to run SHOW GRANTS for the old user, find/replace what you want to change regarding the user's name and/or host and run them and then finally DROP USER the old user. Not forgetting to run FLUSH PRIVILEGES (best to run this after adding the new users' grants, test the new user, then drop the old user and flush again for good measure).

    > SHOW GRANTS FOR 'olduser'@'oldhost';
    +-----------------------------------------------------------------------------------+
    | Grants for olduser@oldhost                                                        |
    +-----------------------------------------------------------------------------------+
    | GRANT USAGE ON *.* TO 'olduser'@'oldhost' IDENTIFIED BY PASSWORD '*PASSHASH'      |
    | GRANT SELECT ON `db`.* TO 'olduser'@'oldhost'                                     |
    +-----------------------------------------------------------------------------------+
    2 rows in set (0.000 sec)

    > GRANT USAGE ON *.* TO 'newuser'@'newhost' IDENTIFIED BY PASSWORD '*SAME_PASSHASH';
    Query OK, 0 rows affected (0.006 sec)

    > GRANT SELECT ON `db`.* TO 'newuser'@'newhost';
    Query OK, 0 rows affected (0.007 sec)

    > DROP USER 'olduser'@'oldhost';
    Query OK, 0 rows affected (0.016 sec)

How can I send and receive WebSocket messages on the server side?

PHP Implementation:

function encode($message)
{
    $length = strlen($message);

    $bytesHeader = [];
    $bytesHeader[0] = 129; // 0x1 text frame (FIN + opcode)

    if ($length <= 125) {
            $bytesHeader[1] = $length;
    } else if ($length >= 126 && $length <= 65535) {
            $bytesHeader[1] = 126;
            $bytesHeader[2] = ( $length >> 8 ) & 255;
            $bytesHeader[3] = ( $length      ) & 255;
    } else {
            $bytesHeader[1] = 127;
            $bytesHeader[2] = ( $length >> 56 ) & 255;
            $bytesHeader[3] = ( $length >> 48 ) & 255;
            $bytesHeader[4] = ( $length >> 40 ) & 255;
            $bytesHeader[5] = ( $length >> 32 ) & 255;
            $bytesHeader[6] = ( $length >> 24 ) & 255;
            $bytesHeader[7] = ( $length >> 16 ) & 255;
            $bytesHeader[8] = ( $length >>  8 ) & 255;
            $bytesHeader[9] = ( $length       ) & 255;
    }

    $str = implode(array_map("chr", $bytesHeader)) . $message;

    return $str;
}

Objective-C: Reading a file line by line

The appropriate way to read text files in Cocoa/Objective-C is documented in Apple's String programming guide. The section for reading and writing files should be just what you're after. PS: What's a "line"? Two sections of a string separated by "\n"? Or "\r"? Or "\r\n"? Or maybe you're actually after paragraphs? The previously mentioned guide also includes a section on splitting a string into lines or paragraphs. (This section is called "Paragraphs and Line Breaks", and is linked to in the left-hand-side menu of the page I pointed to above. Unfortunately this site doesn't allow me to post more than one URL as I'm not a trustworthy user yet.)

To paraphrase Knuth: premature optimisation is the root of all evil. Don't simply assume that "reading the whole file into memory" is slow. Have you benchmarked it? Do you know that it actually reads the whole file into memory? Maybe it simply returns a proxy object and keeps reading behind the scenes as you consume the string? (Disclaimer: I have no idea if NSString actually does this. It conceivably could.) The point is: first go with the documented way of doing things. Then, if benchmarks show that this doesn't have the performance you desire, optimise.

Storing SHA1 hash values in MySQL

So the length is between 10 16-bit chars, and 40 hex digits.

In any case decide the format you are going to store, and make the field a fixed size based on that format. That way you won't have any wasted space.

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

If you use Spring framework in your project, then you can use StringUtils

import org.springframework.util.StringUtils;

StringUtils.getFilenameExtension("YourFileName")

How to use function srand() with time.h?

Try to call randomize() before rand() to initialize random generator.

(look at: srand() — why call it only once?)

Debugging "Element is not clickable at point" error

This might help someone who is using WebdriverIO:

function(){
    var runInBrowser = function(argument) { 
        argument.click();
    };
    var elementToClickOn = browser.$('element');
    browser.execute(runInBrowser, elementToClickOn);
}

Source : https://www.intricatecloud.io/2018/11/webdriverio-tips-element-wrapped-in-div-is-not-clickable/

How to find a value in an array of objects in JavaScript?

jQuery has a built-in method jQuery.grep that works similarly to the ES5 filter function from @adamse's Answer and should work fine on older browsers.

Using adamse's example:

var peoples = [
  { "name": "bob", "dinner": "pizza" },
  { "name": "john", "dinner": "sushi" },
  { "name": "larry", "dinner": "hummus" }
];

you can do the following

jQuery.grep(peoples, function (person) { return person.dinner == "sushi" });
  // => [{ "name": "john", "dinner": "sushi" }]

Android Get Application's 'Home' Data Directory

To get the path of file in application package;

ContextWrapper c = new ContextWrapper(this);
Toast.makeText(this, c.getFilesDir().getPath(), Toast.LENGTH_LONG).show();

How to access the php.ini file in godaddy shared hosting linux

Procedures:

  • Go to your CPanel
  • Select PHP version
  • Click on the link Switch to PHP options
  • Edit your configuration
  • don't forget to click save

enter image description here

You can also follow this screencast

https://www.youtube.com/watch?v=tdUlIkZcOe0

How to fetch the row count for all tables in a SQL SERVER database

Don't use SELECT COUNT(*) FROM TABLENAME, since that is a resource intensive operation. One should use SQL Server Dynamic Management Views or System Catalogs to get the row count information for all tables in a database.

How to Delete Session Cookie?

A session cookie is just a normal cookie without an expiration date. Those are handled by the browser to be valid until the window is closed or program is quit.

But if the cookie is a httpOnly cookie (a cookie with the httpOnly parameter set), you cannot read, change or delete it from outside of HTTP (meaning it must be changed on the server).

DateTime.Today.ToString("dd/mm/yyyy") returns invalid DateTime Value

In addition to what the other answers have said, note that the '/' character in "dd/MM/yyyy" is not a literal character: it represents the date separator of the current user's culture. Therefore, if the current culture uses yyyy-MM-dd dates, then when you call toString it will give you a date such as "31-12-2016" (using dashes instead of slashes). To force it to use slashes, you need to escape that character:

DateTime.Now.ToString("dd/MM/yyyy")     --> "19-12-2016" for a Japanese user
DateTime.Now.ToString("dd/MM/yyyy")     --> "19/12/2016" for a UK user
DateTime.Now.ToString("dd\\/MM\\/yyyy") --> "19/12/2016" independent of region

What exactly is an instance in Java?

The Literal meaning of instance is "an example or single occurrence of something." which is very closer to the Instance in Java terminology.

Java follows dynamic loading, which is not like C language where the all code is copied into the RAM at runtime. Lets capture this with an example.

   class A
    {
    int x=0;
    public static void main(String [] args)    
     {
    int y=0;
    y=y+1;
    x=x+1;
     }   

    }

Let us compile and run this code.

step 1: javac A.class (.class file is generated which is byte code)

step 2: java A (.class file is converted into executable code)

During the step 2,The main method and the static elements are loaded into the RAM for execution. In the above scenario, No issue until the line y=y+1. But whenever x=x+1 is executed, the run time error will be thrown as the JVM does not know what the x is which is declared outside the main method(non-static).

So If by some means the content of .class file is available in the memory for CPU to execute, there is no more issue.

This is done through creating the Object and the keyword NEW does this Job.

"The concept of reserving memory in the RAM for the contents of hard disk (here .class file) at runtime is called Instance "

The Object is also called the instance of the class.

Can an Android Toast be longer than Toast.LENGTH_LONG?

LONG_DELAY toast display for 3.5 sec and SHORT_DELAY toast display for 2 sec.

Toast internally use INotificationManager and calls it's enqueueToast method every time a Toast.show() is called.

Call the show() with SHORT_DELAY twice will enqueue same toast again. it will display for 4 sec ( 2 sec + 2 sec).

similarly, call the show() with LONG_DELAY twice will enqueue same toast again. it will display for 7 sec ( 3.5 sec + 3.5 sec)

Get nth character of a string in Swift programming language

Swift 5.3

I think this is very elegant. Kudos at Paul Hudson of "Hacking with Swift" for this solution:

@available (macOS 10.15, * )
extension String {
    subscript(idx: Int) -> String {
        String(self[index(startIndex, offsetBy: idx)])
    }
}

Then to get one character out of the String you simply do:

var string = "Hello, world!"

var firstChar = string[0] // No error, returns "H" as a String

notifyDataSetChanged example

I had the same problem and I prefer not to replace the entire ArrayAdapter with a new instance continuously. Thus I have the AdapterHelper do the heavy lifting somewhere else.

Add this where you would normally (try to) call notify

new AdapterHelper().update((ArrayAdapter)adapter, new ArrayList<Object>(yourArrayList));
adapter.notifyDataSetChanged();

AdapterHelper class

public class AdapterHelper {
    @SuppressWarnings({ "rawtypes", "unchecked" })
    public void update(ArrayAdapter arrayAdapter, ArrayList<Object> listOfObject){
        arrayAdapter.clear();
        for (Object object : listOfObject){
            arrayAdapter.add(object);
        }
    }
}

Python convert object to float

  • You can use pandas.Series.astype
  • You can do something like this :

    weather["Temp"] = weather.Temp.astype(float)
    
  • You can also use pd.to_numeric that will convert the column from object to float

  • For details on how to use it checkout this link :http://pandas.pydata.org/pandas-docs/version/0.20/generated/pandas.to_numeric.html
  • Example :

    s = pd.Series(['apple', '1.0', '2', -3])
    print(pd.to_numeric(s, errors='ignore'))
    print("=========================")
    print(pd.to_numeric(s, errors='coerce'))
    
  • Output:

    0    apple
    1      1.0
    2        2
    3       -3
    =========================
    dtype: object
    0    NaN
    1    1.0
    2    2.0
    3   -3.0
    dtype: float64
    
  • In your case you can do something like this:

    weather["Temp"] = pd.to_numeric(weather.Temp, errors='coerce')
    
  • Other option is to use convert_objects
  • Example is as follows

    >> pd.Series([1,2,3,4,'.']).convert_objects(convert_numeric=True)
    
    0     1
    1     2
    2     3
    3     4
    4   NaN
    dtype: float64
    
  • You can use this as follows:

    weather["Temp"] = weather.Temp.convert_objects(convert_numeric=True)
    
  • I have showed you examples because if any of your column won't have a number then it will be converted to NaN... so be careful while using it.

Conditionally change img src based on model data

Another alternative (other than binary operators suggested by @jm-) is to use ng-switch:

<span ng-switch on="interface">
   <img ng-switch-when="UP" src='green-checkmark.png'>
   <img ng-switch-default   src='big-black-X.png'>
</span>

ng-switch will likely be better/easier if you have more than two images.

How do the PHP equality (== double equals) and identity (=== triple equals) comparison operators differ?

The operator == casts between two different types if they are different, while the === operator performs a 'typesafe comparison'. That means that it will only return true if both operands have the same type and the same value.

Examples:

1 === 1: true
1 == 1: true
1 === "1": false // 1 is an integer, "1" is a string
1 == "1": true // "1" gets casted to an integer, which is 1
"foo" === "foo": true // both operands are strings and have the same value

Warning: two instances of the same class with equivalent members do NOT match the === operator. Example:

$a = new stdClass();
$a->foo = "bar";
$b = clone $a;
var_dump($a === $b); // bool(false)

How do I include image files in Django templates?

In development
In your app folder create folder name 'static' and save your picture in that folder.
To use picture use:

<html>
    <head>
       {% load staticfiles %} <!-- Prepare django to load static files -->
    </head>
    <body>
        <img src={% static "image.jpg" %}>
    </body>
</html>

In production:
Everything same like in development, just add couple more parameters for Django:

  1. add in settings.py
    STATIC_ROOT = os.path.join(BASE_DIR, "static/")(this will prepare folder where static files from all apps will be stored)

  2. be sure your app is in INSTALLED_APPS = ['myapp',]

  3. in terminall run command python manage.py collectstatic (this will make copy of static files from all apps included in INSTALLED_APPS to global static folder - STATIC_ROOT folder )

    Thats all what Django need, after this you need to make some web server side setup to make premissions for use static folder. E.g. in apache2 in configuration file httpd.conf (for windows) or sites-enabled/000-default.conf. (under site virtual host part for linux) add:

    Alias \static "path_to_your_project\static"

    Require all granted

    And that's all

How to use not contains() in xpath?

Should be xpath with not contains() method, //production[not(contains(category,'business'))]

How to split long commands over multiple lines in PowerShell

In PowerShell 5 and PowerShell 5 ISE, it is also possible to use just Shift + Enter for multiline editing (instead of standard backticks ` at the end of each line):

PS> &"C:\Program Files\IIS\Microsoft Web Deploy\msdeploy.exe" # Shift+Enter
>>> -verb:sync # Shift+Enter
>>> -source:contentPath="c:\workspace\xxx\master\Build\_PublishedWebsites\xxx.Web" # Shift+Enter
>>> -dest:contentPath="c:\websites\xxx\wwwroot,computerName=192.168.1.1,username=administrator,password=xxx"

Get current NSDate in timestamp format

To get timestamp from NSDate Swift 3

func getCurrentTimeStampWOMiliseconds(dateToConvert: NSDate) -> String {
    let objDateformat: DateFormatter = DateFormatter()
    objDateformat.dateFormat = "yyyy-MM-dd HH:mm:ss"
    let strTime: String = objDateformat.string(from: dateToConvert as Date)
    let objUTCDate: NSDate = objDateformat.date(from: strTime)! as NSDate
    let milliseconds: Int64 = Int64(objUTCDate.timeIntervalSince1970)
    let strTimeStamp: String = "\(milliseconds)"
    return strTimeStamp
}

To use

let now = NSDate()
let nowTimeStamp = self.getCurrentTimeStampWOMiliseconds(dateToConvert: now)

Send form data using ajax

The code you've posted has two problems:

First: <input type="buttom" should be <input type="button".... This probably is just a typo but without button your input will be treated as type="text" as the default input type is text.

Second: In your function f() definition, you are using the form parameter thinking it's already a jQuery object by using form.attr("action"). Then similarly in the $.post method call, you're passing fname and lname which are HTMLInputElements. I believe what you want is form's action url and input element's values.

Try with the following changes:

HTML

<form action="/echo/json/" method="post">
    <input type="text" name="lname" />
    <input type="text" name="fname" />

    <!-- change "buttom" to "button" -->
    <input type="button" name="send" onclick="return f(this.form ,this.form.fname ,this.form.lname) " />
</form>

JavaScript

function f(form, fname, lname) {
    att = form.action; // Use form.action
    $.post(att, {
        fname: fname.value, // Use fname.value
        lname: lname.value // Use lname.value
    }).done(function (data) {
        alert(data);
    });
    return true;
}

Here is the fiddle.

Can I use wget to check , but not download

You can use the following option to check for the files:

wget --delete-after URL

PHP file_get_contents() returns "failed to open stream: HTTP request failed!"

I got a similar problem.

Due to timeout !

Timeout can be indicated like this :

$options = array(
    'http' => array(
        'header'  => "Content-type: application/x-www-form-urlencoded\r\n",
        'method'  => "POST",
        'content' => http_build_query($data2),
        'timeout' => 30,
    ),
);
$context = stream_context_create($options); $retour =
$retour = @file_get_contents("http://xxxxx.xxx/xxxx", false, $context);

EXEC sp_executesql with multiple parameters

maybe this help :

declare 
@statement AS NVARCHAR(MAX)
,@text1 varchar(50)='hello'
,@text2 varchar(50)='world'

set @statement = '
select '''+@text1+''' + '' beautifull '' + ''' + @text2 + ''' 
'
exec sp_executesql @statement;

this is same as below :

select @text1 + ' beautifull ' + @text2

How to check if a specified key exists in a given S3 bucket using Java

The right way to do it in SDK V2, without the overload of actually getting the object, is to use S3Client.headObject. Officially backed by AWS Change Log.

Example code:

public boolean exists(String bucket, String key) {
    try {
        HeadObjectResponse headResponse = client
                .headObject(HeadObjectRequest.builder().bucket(bucket).key(key).build());
        return true;
    } catch (NoSuchKeyException e) {
        return false;
    }
}

CSS submit button weird rendering on iPad/iPhone

The above answer for webkit appearance worked, but the button still looked kind pale/dull compared to the browser on other devices/desktop. I also had to set opacity to full (ranges from 0 to 1)

-webkit-appearance:none;
opacity: 1

After setting the opacity, the button looked the same on all the different devices/emulator/desktop.

How to compare datetime with only date in SQL Server

You can use LIKE statement instead of =. But to do this with DateStamp you need to CONVERT it first to VARCHAR:

SELECT * 
FROM [User] U
WHERE CONVERT(VARCHAR, U.DateCreated, 120) LIKE '2014-02-07%'

How do I display a decimal value to 2 decimal places?

Mike M.'s answer was perfect for me on .NET, but .NET Core doesn't have a decimal.Round method at the time of writing.

In .NET Core, I had to use:

decimal roundedValue = Math.Round(rawNumber, 2, MidpointRounding.AwayFromZero);

A hacky method, including conversion to string, is:

public string FormatTo2Dp(decimal myNumber)
{
    // Use schoolboy rounding, not bankers.
    myNumber = Math.Round(myNumber, 2, MidpointRounding.AwayFromZero);

    return string.Format("{0:0.00}", myNumber);
}

Python error when trying to access list by index - "List indices must be integers, not str"

Were you expecting player to be a dict rather than a list?

>>> player=[1,2,3]
>>> player["score"]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: list indices must be integers, not str
>>> player={'score':1, 'age': 2, "foo":3}
>>> player['score']
1

IIS 500.19 with 0x80070005 The requested page cannot be accessed because the related configuration data for the page is invalid error

Check the Error/HResult Code and follow this guide:

0x80070005

This problem occurs for one of the following reasons:

  • You are using IIS 7.0 on a computer that is running Windows Vista. Additionally, you configure the Web site to use UNC Passthrough authentication to access a remote Universal Naming Convention (UNC) share.

The IIS_IUSRS group does not have the appropriate permissions for the ApplicationHost.config file, for the Web.config file, or for the virtual/application directories of IIS.

Solution

Method 1

Do not configure the Web site to use UNC Passthrough authentication to access the remote UNC share. Instead, specify a user account that has the appropriate permissions to access the remote UNC share.

Method 2 (most likely)

Grant the Read permission to the IIS_IUSRS group for the ApplicationHost.config file or for the Web.config file.

So in simple words, you need to:

  1. Open Properties of the folder containing your reported Config File (such as Web.config).
  2. In Security tab, Edit... and Add...: IIS_IUSRS group and confirm.

How can I insert new line/carriage returns into an element.textContent?

None of the above solutions worked for me. I was trying to add a line feed and additional text to a <p> element. I typically use Firefox, but I do need browser compatibility. I read that only Firefox supports the textContent property, only Internet Explorer supports the innerText property, but both support the innerHTML property. However, neither adding <br /> nor \n nor \r\n to any of those properties resulted in a new line. The following, however, did work:

<html>
<body>
<script type="text/javascript">
  function modifyParagraph() {

  var p;
  p=document.getElementById("paragraphID");
  p.appendChild(document.createElement("br"));
  p.appendChild(document.createTextNode("Additional text."));
}    
</script>

<p id="paragraphID">Original text.</p>

<input type="button" id="pbutton" value="Modify Paragraph" onClick="modifyParagraph()" />
</body>
</html>

Current time in microseconds in java

You could maybe create a component that determines the offset between System.nanoTime() and System.currentTimeMillis() and effectively get nanoseconds since epoch.

public class TimerImpl implements Timer {

    private final long offset;

    private static long calculateOffset() {
        final long nano = System.nanoTime();
        final long nanoFromMilli = System.currentTimeMillis() * 1_000_000;
        return nanoFromMilli - nano;
    }

    public TimerImpl() {
        final int count = 500;
        BigDecimal offsetSum = BigDecimal.ZERO;
        for (int i = 0; i < count; i++) {
            offsetSum = offsetSum.add(BigDecimal.valueOf(calculateOffset()));
        }
        offset = (offsetSum.divide(BigDecimal.valueOf(count))).longValue();
    }

    public long nowNano() {
        return offset + System.nanoTime();
    }

    public long nowMicro() {
        return (offset + System.nanoTime()) / 1000;
    }

    public long nowMilli() {
        return System.currentTimeMillis();
    }
}

Following test produces fairly good results on my machine.

    final Timer timer = new TimerImpl();
    while (true) {
        System.out.println(timer.nowNano());
        System.out.println(timer.nowMilli());
    }

The difference seems to oscillate in range of +-3ms. I guess one could tweak the offset calculation a bit more.

1495065607202174413
1495065607203
1495065607202177574
1495065607203
...
1495065607372205730
1495065607370
1495065607372208890
1495065607370
...

Dynamically create and submit form

Steps to take:

  1. First you need to create the form element.
  2. With the form you have to pass the URL to which you wants to navigate.
  3. Specify the method type for the form.
  4. Add the form body.
  5. Finally call the submit() method on the form.

Code:

var Form = document.createElement("form");
Form.action = '/DashboardModule/DevicesInfo/RedirectToView?TerminalId='+marker.data;
Form.method = "post";
var formToSubmit = document.body.appendChild(Form);
formToSubmit.submit();

How to obtain the absolute path of a file via Shell (BASH/ZSH/SH)?

Forget about readlink and realpath which may or may not be installed on your system.

Expanding on dogbane's answer above here it is expressed as a function:

#!/bin/bash
get_abs_filename() {
  # $1 : relative filename
  echo "$(cd "$(dirname "$1")" && pwd)/$(basename "$1")"
}

you can then use it like this:

myabsfile=$(get_abs_filename "../../foo/bar/file.txt")

How and why does it work?

The solution exploits the fact that the Bash built-in pwd command will print the absolute path of the current directory when invoked without arguments.

Why do I like this solution ?

It is portable and doesn't require neither readlink or realpath which often does not exist on a default install of a given Linux/Unix distro.

What if dir doesn't exist?

As given above the function will fail and print on stderr if the directory path given does not exist. This may not be what you want. You can expand the function to handle that situation:

#!/bin/bash
get_abs_filename() {
  # $1 : relative filename
  if [ -d "$(dirname "$1")" ]; then
    echo "$(cd "$(dirname "$1")" && pwd)/$(basename "$1")"
  fi
}

Now it will return an empty string if one the parent dirs do not exist.

How do you handle trailing '..' or '.' in input ?

Well, it does give an absolute path in that case, but not a minimal one. It will look like:

/Users/bob/Documents/..

If you want to resolve the '..' you will need to make the script like:

get_abs_filename() {
  # $1 : relative filename
  filename=$1
  parentdir=$(dirname "${filename}")

  if [ -d "${filename}" ]; then
      echo "$(cd "${filename}" && pwd)"
  elif [ -d "${parentdir}" ]; then
    echo "$(cd "${parentdir}" && pwd)/$(basename "${filename}")"
  fi
}

How can I compare two lists in python and return matches

Do you want duplicates? If not maybe you should use sets instead:

>>> set([1, 2, 3, 4, 5]).intersection(set([9, 8, 7, 6, 5]))
set([5])

How to convert a timezone aware string to datetime in Python without dateutil?

You can convert like this.

date = datetime.datetime.strptime('2019-3-16T5-49-52-595Z','%Y-%m-%dT%H-%M-%S-%f%z')
date_time = date.strftime('%Y-%m-%dT%H:%M:%S.%fZ')

How to import functions from different js file in a Vue+webpack+vue-loader project

Say I want to import data into a component from src/mylib.js:

var test = {
  foo () { console.log('foo') },
  bar () { console.log('bar') },
  baz () { console.log('baz') }
}

export default test

In my .Vue file I simply imported test from src/mylib.js:

<script> 
  import test from '@/mylib'

  console.log(test.foo())
  ...
</script>

Tuple unpacking in for loops

The enumerate function returns a generator object which, at each iteration, yields a tuple containing the index of the element (i), numbered starting from 0 by default, coupled with the element itself (a), and the for loop conveniently allows you to access both fields of those generated tuples and assign variable names to them.

What causes java.lang.IncompatibleClassChangeError?

I had the same issue, and later I figured out that I am running the application on Java version 1.4 while the application is compiled on version 6.

Actually, the reason was of having a duplicate library, one is located within the classpath and the other one is included inside a jar file that is located within the classpath.

What is the argument for printf that formats a long?

In case you're looking to print unsigned long long as I was, use:

unsigned long long n;
printf("%llu", n);

For all other combinations, I believe you use the table from the printf manual, taking the row, then column label for whatever type you're trying to print (as I do with printf("%llu", n) above).

Changing background color of selected cell?

For iOS7+ and if you are using Interface Builder then subclass your cell and implement:

Objective-C

- (void)awakeFromNib {
    [super awakeFromNib];
    // Default Select background
    UIView *v = [[UIView alloc] init];
    v.backgroundColor = [UIColor redColor];
    self.selectedBackgroundView = v;
}

Swift 2.2

override func awakeFromNib() {
    super.awakeFromNib()
    // Default Select background
    self.selectedBackgroundView = { view in
        view.backgroundColor = .redColor()
        return view
    }(UIView())
}

Set database timeout in Entity Framework

Same as other answers, but as an extension method:

static class Extensions
{
    public static void SetCommandTimeout(this IObjectContextAdapter db, TimeSpan? timeout)
    {
        db.ObjectContext.CommandTimeout = timeout.HasValue ? (int?) timeout.Value.TotalSeconds : null;
    }
}

Making a <button> that's a link in HTML

You have three options:

  • Style links to look like buttons using CSS.

    Just look at the light blue "tags" under your question.

    It is possible, even to give them a depressed appearance when clicked (using pseudo-classes like :active), without any scripting. Lots of major sites, such as Google, are starting to make buttons out of CSS styles these days anyway, scripting or not.

  • Put a separate <form> element around each one.

    As you mentioned in the question. Easy and will definitely work without Javascript (or even CSS). But it adds a little extra code which may look untidy.

  • Rely on Javascript.

    Which is what you said you didn't want to do.

Download old version of package with NuGet

In NuGet 3.x (Visual Studio 2015) you can just select the version from the UI

NuGet 3 package manager UI

How to debug stored procedures with print statements?

try using:

RAISERROR('your message here!!!',0,1) WITH NOWAIT

you could also try switching to "Results to Text" it is just a few icons to the right of "Execute" on the default tool bar.

With both of the above in place, and you still you do not see the messages, make sure you are running the same server/database/owner version of the procedure that you are editing. Make sure you are hitting the RAISERROR command, make it the first command inside the procedure.

If all else fails, you could create a table:

create table temp_log (RowID int identity(1,1) primary key not null
                      , MessageValue varchar(255))

then:

INSERT INTO temp_log VALUES ('Your message here')

then after running the procedure (provided no rollbacks) just select the table.

Create hive table using "as select" or "like" and also specify delimiter

Both the answers provided above work fine.

  1. CREATE TABLE person AS select * from employee;
  2. CREATE TABLE person LIKE employee;

Implementing a slider (SeekBar) in Android

How to implement a SeekBar

enter image description here

Add the SeekBar to your layout

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/textView"
        android:layout_margin="20dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

    <SeekBar
        android:id="@+id/seekBar"
        android:max="100"
        android:progress="50"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

</LinearLayout>

Notes

  • max is the highest value that the seek bar can go to. The default is 100. The minimum is 0. The xml min value is only available from API 26, but you can just programmatically convert the 0-100 range to whatever you need for earlier versions.
  • progress is the initial position of the slider dot (called a "thumb").
  • For a vertical SeekBar use android:rotation="270".

Listen for changes in code

public class MainActivity extends AppCompatActivity {

    TextView tvProgressLabel;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // set a change listener on the SeekBar
        SeekBar seekBar = findViewById(R.id.seekBar);
        seekBar.setOnSeekBarChangeListener(seekBarChangeListener);

        int progress = seekBar.getProgress();
        tvProgressLabel = findViewById(R.id.textView);
        tvProgressLabel.setText("Progress: " + progress);
    }

    SeekBar.OnSeekBarChangeListener seekBarChangeListener = new SeekBar.OnSeekBarChangeListener() {

        @Override
        public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
            // updated continuously as the user slides the thumb
            tvProgressLabel.setText("Progress: " + progress);
        }

        @Override
        public void onStartTrackingTouch(SeekBar seekBar) {
            // called when the user first touches the SeekBar
        }

        @Override
        public void onStopTrackingTouch(SeekBar seekBar) {
            // called after the user finishes moving the SeekBar
        }
    };
}

Notes

  • If you don't need to do any updates while the user is moving the seekbar, then you can just update the UI in onStopTrackingTouch.

See also

How can I check if given int exists in array?

You almost never have to write your own loops in C++. Here, you can use std::find.

const int toFind = 42;
int* found = std::find (myArray, std::end (myArray), toFind);
if (found != std::end (myArray))
{
  std::cout << "Found.\n"
}
else
{
  std::cout << "Not found.\n";
}

std::end requires C++11. Without it, you can find the number of elements in the array with:

const size_t numElements = sizeof (myArray) / sizeof (myArray[0]);

...and the end with:

int* end = myArray + numElements;

HTML combo box with option to type an entry

The dojo example here do not work when applied to existing code in most cases. Therefor I had to find an alternate, found here - hxxp://technologymantrablog.com/how-to-create-a-combo-box-with-text-input-jquery-autocomplete/ (now points to a spam site or worse)

archive.org (not very useful)

Here is the jsfiddle - https://jsfiddle.net/ze7fgby7/

Spark DataFrame TimestampType - how to get Year, Month, Day values from field?

Actually, we really do not need to import any python library. We can separate the year, month, date using simple SQL. See the below example,

+----------+
|       _c0|
+----------+
|1872-11-30|
|1873-03-08|
|1874-03-07|
|1875-03-06|
|1876-03-04|
|1876-03-25|
|1877-03-03|
|1877-03-05|
|1878-03-02|
|1878-03-23|
|1879-01-18|

I have a date column in my data frame which contains the date, month and year and assume I want to extract only the year from the column.

df.createOrReplaceTempView("res")
sqlDF = spark.sql("SELECT EXTRACT(year from `_c0`) FROM res ")

Here I'm creating a temporary view and store the year values using this single line and the output will be,

+-----------------------+
|year(CAST(_c0 AS DATE))|
+-----------------------+
|                   1872|
|                   1873|
|                   1874|
|                   1875|
|                   1876|
|                   1876|
|                   1877|
|                   1877|
|                   1878|
|                   1878|
|                   1879|
|                   1879|
|                   1879|

how to delete a specific row in codeigniter?

It will come in the url so you can get it by two ways. Fist one

<td><?php echo anchor('textarea/delete_row', 'DELETE', 'id="$row->id"'); ?></td>
$id = $this->input->get('id');

2nd one.

$id = $this->uri->segment(3);

But in the second method you have to count the no. of segments in the url that on which no. your id come. 2,3,4 etc. then you have to pass. then in the ();

Get absolute path to workspace directory in Jenkins Pipeline plugin

Note: this solution works only if the slaves have the same directory structure as the master. pwd() will return the workspace directory on the master due to JENKINS-33511.

I used to do it using pwd() functionality of pipeline plugin. So, if you need to get a workspace on slave, you may do smth like this:

node('label'){
    //now you are on slave labeled with 'label'
    def workspace = pwd()
    //${workspace} will now contain an absolute path to job workspace on slave 
}

Append text to file from command line without using io redirection

If you don't mind using sed then,

$ cat test 
this is line 1
$ sed -i '$ a\this is line 2 without redirection' test 
$ cat test 
this is line 1
this is line 2 without redirection

As the documentation may be a bit long to go through, some explanations :

  • -i means an inplace transformation, so all changes will occur in the file you specify
  • $ is used to specify the last line
  • a means append a line after
  • \ is simply used as a delimiter

What's your most controversial programming opinion?

Relational Databases are a waste of time. Use object databases instead!

Relational database vendors try to fool us into believing that the only scaleable, persistent and safe storage in the world is relational databases. I am a certified DBA. Have you ever spent hours trying to optimize a query and had no idea what was going wrong? Relational databases don't let you make your own search paths when you need them. You give away much of the control over the speed of your app into the hands of people you've never met and they are not as smart as you think.

Sure, sometimes in a well-maintained database they come up with a quick answer for a complex query. But the price you pay for this is too high! You have to choose between writing raw SQL every time you want to read an entry of your data, which is dangerous. Or use an Object relational mapper which adds more complexity and things outside your control.

More importantly, you are actively forbidden from coming up with smart search algorithms, because every damn roundtrip to the database costs you around 11ms. It is too much. Imagine you know this super-graph algorithm which will answer a specific question, which might not even be expressible in SQL!, in due time. But even if your algorithm is linear, and interesting algorithms are not linear, forget about combining it with a relational database as enumerating a large table will take you hours!

Compare that with SandstoneDb, or Gemstone for Smalltalk! If you are into Java, give db4o a shot.

So, my advice is: Use an object-DB. Sure, they aren't perfect and some queries will be slower. But you will be surprised how many will be faster. Because loading the objects will not require all these strange transofmations between SQL and your domain data. And if you really need speed for a certain query, object databases have the query optimizer you should trust: your brain.

How to open spss data files in excel?

I help develop the Colectica for Excel addin, which opens SPSS and Stata data files in Excel. This does not require ODBC configuration; it reads the file and then inserts the data and metadata into your worksheet.

The addin is downloadable from http://www.colectica.com/software/colecticaforexcel

Check if user is using IE

Using modernizr

Modernizr.addTest('ie', function () {
    var ua = window.navigator.userAgent;
    var msie = ua.indexOf('MSIE ') > 0;
    var ie11 = ua.indexOf('Trident/') > 0;
    var ie12 = ua.indexOf('Edge/') > 0;
    return msie || ie11 || ie12;
});

How to get my Android device Internal Download Folder path

if a device has an SD card, you use:

Environment.getExternalStorageState() 

if you don't have an SD card, you use:

Environment.getDataDirectory()

if there is no SD card, you can create your own directory on the device locally.

    //if there is no SD card, create new directory objects to make directory on device
        if (Environment.getExternalStorageState() == null) {
                        //create new file directory object
            directory = new File(Environment.getDataDirectory()
                    + "/RobotiumTestLog/");
            photoDirectory = new File(Environment.getDataDirectory()
                    + "/Robotium-Screenshots/");
            /*
             * this checks to see if there are any previous test photo files
             * if there are any photos, they are deleted for the sake of
             * memory
             */
            if (photoDirectory.exists()) {
                File[] dirFiles = photoDirectory.listFiles();
                if (dirFiles.length != 0) {
                    for (int ii = 0; ii <= dirFiles.length; ii++) {
                        dirFiles[ii].delete();
                    }
                }
            }
            // if no directory exists, create new directory
            if (!directory.exists()) {
                directory.mkdir();
            }

            // if phone DOES have sd card
        } else if (Environment.getExternalStorageState() != null) {
            // search for directory on SD card
            directory = new File(Environment.getExternalStorageDirectory()
                    + "/RobotiumTestLog/");
            photoDirectory = new File(
                    Environment.getExternalStorageDirectory()
                            + "/Robotium-Screenshots/");
            if (photoDirectory.exists()) {
                File[] dirFiles = photoDirectory.listFiles();
                if (dirFiles.length > 0) {
                    for (int ii = 0; ii < dirFiles.length; ii++) {
                        dirFiles[ii].delete();
                    }
                    dirFiles = null;
                }
            }
            // if no directory exists, create new directory to store test
            // results
            if (!directory.exists()) {
                directory.mkdir();
            }
        }// end of SD card checking

add permissions on your manifest.xml

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Happy coding..

How to see the changes in a Git commit?

In case of checking the source change in a graphical view,

$gitk (Mention your commit id here)

for example:

$gitk HEAD~1 

No Access-Control-Allow-Origin header is present on the requested resource

On your servlet simply override the service method of your servlet so that you can add headers for all your http methods (POST, GET, DELETE, PUT, etc...).

@Override
    protected void service(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {

        if(("http://www.example.com").equals(req.getHeader("origin"))){
            res.setHeader("Access-Control-Allow-Origin", req.getHeader("origin"));
            res.setHeader("Access-Control-Allow-Headers", "Authorization");
        }

        super.service(req, res);
    }

Add a border outside of a UIView (instead of inside)

Ok, there already is an accepted answer but I think there is a better way to do it, you just have to had a new layer a bit larger than your view and do not mask it to the bounds of the view's layer (which actually is the default behaviour). Here is the sample code :

CALayer * externalBorder = [CALayer layer];
externalBorder.frame = CGRectMake(-1, -1, myView.frame.size.width+2, myView.frame.size.height+2);
externalBorder.borderColor = [UIColor blackColor].CGColor;
externalBorder.borderWidth = 1.0;

[myView.layer addSublayer:externalBorder];
myView.layer.masksToBounds = NO;

Of course this is if you want your border to be 1 unity large, if you want more you adapt the borderWidth and the frame of the layer accordingly. This is better than using a second view a bit larger as a CALayer is lighter than a UIView and you don't have do modify the frame of myView, which is good for instance if myView is aUIImageView

N.B : For me the result was not perfect on simulator (the layer was not exactly at the right position so the layer was thicker on one side sometimes) but was exactly what is asked for on real device.

EDIT

Actually the problem I talk about in the N.B was just because I had reduced the screen of the simulator, on normal size there is absolutely no issue

Hope it helps

How do I obtain a list of all schemas in a Sql Server database

You can also query the INFORMATION_SCHEMA.SCHEMATA view:

SELECT SCHEMA_NAME FROM INFORMATION_SCHEMA.SCHEMATA

I believe querying the INFORMATION_SCHEMA views is recommended as they protect you from changes to the underlying sys tables. From the SQL Server 2008 R2 Help:

Information schema views provide an internal, system table-independent view of the SQL Server metadata. Information schema views enable applications to work correctly although significant changes have been made to the underlying system tables. The information schema views included in SQL Server comply with the ISO standard definition for the INFORMATION_SCHEMA.

Ironically, this is immediately preceded by this note:

Some changes have been made to the information schema views that break backward compatibility. These changes are described in the topics for the specific views.

sql use statement with variable

I case that someone need a solution for this, this is one:

if you use a dynamic USE statement all your query need to be dynamic, because it need to be everything in the same context.

You can try with SYNONYM, is basically an ALIAS to a specific Table, this SYNONYM is inserted into the sys.synonyms table so you have access to it from any context

Look this static statement:

CREATE SYNONYM MASTER_SCHEMACOLUMNS FOR Master.INFORMATION_SCHEMA.COLUMNS
SELECT * FROM MASTER_SCHEMACOLUMNS

Now dynamic:

DECLARE @SQL VARCHAR(200)
DECLARE @CATALOG VARCHAR(200) = 'Master'

IF EXISTS(SELECT * FROM  sys.synonyms s WHERE s.name = 'CURRENT_SCHEMACOLUMNS')
BEGIN
DROP SYNONYM CURRENT_SCHEMACOLUMNS
END

SELECT @SQL = 'CREATE SYNONYM CURRENT_SCHEMACOLUMNS FOR '+ @CATALOG +'.INFORMATION_SCHEMA.COLUMNS';
EXEC sp_sqlexec @SQL

--Your not dynamic Code
SELECT * FROM CURRENT_SCHEMACOLUMNS

Now just change the value of @CATALOG and you will be able to list the same table but from different catalog.

Creating an Array from a Range in VBA

Adding to @Vityata 's answer, below is the function I use to convert a row / column vector in a 1D array:

Function convertVecToArr(ByVal rng As Range) As Variant
'convert two dimension array into a one dimension array
    
    Dim arr() As Variant, slicedArr() As Variant
    arr = rng.value   'arr = rng works too (https://bettersolutions.com/excel/cells-ranges/vba-working-with-arrays.htm)
    
    If UBound(arr, 1) > UBound(arr, 2) Then
        slicedArr = Application.WorksheetFunction.Transpose(arr)
    Else
        slicedArr = Application.WorksheetFunction.index(arr, 1, 0)  'If you set row_num or column_num to 0 (zero), Index returns the array of values for the entire column or row, respectively._
                                                                   'To use values returned as an array, enter the Index function as an array formula in a horizontal range of cells for a row,_
                                                                   'and in a vertical range of cells for a column.
                                                                   'https://usefulgyaan.wordpress.com/2013/06/12/vba-trick-of-the-week-slicing-an-array-without-loop-application-index/
    End If
convertVecToArr = slicedArr
End Function

Selected tab's color in Bottom Navigation View

If you want to change icons' and texts' colors programmatically:

ColorStateList iconsColorStates = new ColorStateList(
            new int[][]{
                    new int[]{-android.R.attr.state_checked},
                    new int[]{android.R.attr.state_checked}
            },
            new int[]{
                    Color.parseColor("#123456"),
                    Color.parseColor("#654321")
            });

    ColorStateList textColorStates = new ColorStateList(
            new int[][]{
                    new int[]{-android.R.attr.state_checked},
                    new int[]{android.R.attr.state_checked}
            },
            new int[]{
                    Color.parseColor("#123456"),
                    Color.parseColor("#654321")
            });

    navigation.setItemIconTintList(iconsColorStates);
    navigation.setItemTextColor(textColorStates);

Error: unexpected symbol/input/string constant/numeric constant/SPECIAL in my code

If you are copy-pasting code into R, it sometimes won't accept some special characters such as "~" and will appear instead as a "?". So if a certain character is giving an error, make sure to use your keyboard to enter the character, or find another website to copy-paste from if that doesn't work.

Add property to an array of objects

  Object.defineProperty(Results, "Active", {value : 'true',
                       writable : true,
                       enumerable : true,
                       configurable : true});

How to set up Automapper in ASP.NET Core

In my Startup.cs (Core 2.2, Automapper 8.1.1)

services.AddAutoMapper(new Type[] { typeof(DAL.MapperProfile) });            

In my data access project

namespace DAL
{
    public class MapperProfile : Profile
    {
        // place holder for AddAutoMapper (to bring in the DAL assembly)
    }
}

In my model definition

namespace DAL.Models
{
    public class PositionProfile : Profile
    {
        public PositionProfile()
        {
            CreateMap<Position, PositionDto_v1>();
        }
    }

    public class Position
    {
        ...
    }

Why does LayoutInflater ignore the layout_width and layout_height layout parameters I've specified?

andig is correct that a common reason for LayoutInflater ignoring your layout_params would be because a root was not specified. Many people think you can pass in null for root. This is acceptable for a few scenarios such as a dialog, where you don't have access to root at the time of creation. A good rule to follow, however, is that if you have root, give it to LayoutInflater.

I wrote an in-depth blog post about this that you can check out here:

https://www.bignerdranch.com/blog/understanding-androids-layoutinflater-inflate/

Percentage width in a RelativeLayout

This does not quite answer the original question, which was for a 70/30 split, but in the special case of a 50/50 split between the components there is a way: place an invisible strut at the center and use it to position the two components of interest.

<RelativeLayout 
    android:layout_width="match_parent"
    android:layout_height="wrap_content">
    <View android:id="@+id/strut"
        android:layout_width="0dp"
        android:layout_height="0dp" 
        android:layout_centerHorizontal="true"/>
    <Button
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_alignRight="@id/strut"
        android:layout_alignParentLeft="true"
        android:text="Left"/> 
    <Button 
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@id/strut"
        android:layout_alignParentRight="true"
        android:text="Right"/>
</RelativeLayout>

As this is a pretty common case, this solution is more than a curiosity. It is a bit of a hack but an efficient one because the empty, zero-sized strut should cost very little.

In general, though, it's best not to expect too much from the stock Android layouts...

File Upload ASP.NET MVC 3.0

Alternative method to transfer to byte[] (for saving to DB).

@Arthur's method works pretty good, but doesn't copy perfectly so MS Office documents may fail to open after retrieving them from the database. MemoryStream.GetBuffer() can return extra empty bytes at the end of the byte[], but you can fix that by using MemoryStream.ToArray() instead. However, I found this alternative to work perfectly for all file types:

using (var binaryReader = new BinaryReader(file.InputStream))
{
    byte[] array = binaryReader.ReadBytes(file.ContentLength);
}

Here's my full code:

Document Class:

public class Document
{
    public int? DocumentID { get; set; }
    public string FileName { get; set; }
    public byte[] Data { get; set; }
    public string ContentType { get; set; }
    public int? ContentLength { get; set; }

    public Document()
    {
        DocumentID = 0;
        FileName = "New File";
        Data = new byte[] { };
        ContentType = "";
        ContentLength = 0;
    }
}

File Download:

[HttpGet]
public ActionResult GetDocument(int? documentID)
{
    // Get document from database
    var doc = dataLayer.GetDocument(documentID);

    // Convert to ContentDisposition
    var cd = new System.Net.Mime.ContentDisposition
    {
        FileName = doc.FileName, 

        // Prompt the user for downloading; set to true if you want 
        // the browser to try to show the file 'inline' (display in-browser
        // without prompting to download file).  Set to false if you 
        // want to always prompt them to download the file.
        Inline = true, 
    };
    Response.AppendHeader("Content-Disposition", cd.ToString());

    // View document
    return File(doc.Data, doc.ContentType);
}

File Upload:

[HttpPost]
public ActionResult GetDocument(HttpPostedFileBase file)
{
    // Verify that the user selected a file
    if (file != null && file.ContentLength > 0)
    {
        // Get file info
        var fileName = Path.GetFileName(file.FileName);
        var contentLength = file.ContentLength;
        var contentType = file.ContentType;

        // Get file data
        byte[] data = new byte[] { };
        using (var binaryReader = new BinaryReader(file.InputStream))
        {
            data = binaryReader.ReadBytes(file.ContentLength);
        }

        // Save to database
        Document doc = new Document()
        {
            FileName = fileName,
            Data = data,
            ContentType = contentType,
            ContentLength = contentLength,
        };
        dataLayer.SaveDocument(doc);

        // Show success ...
        return RedirectToAction("Index");
    }
    else
    {
        // Show error ...
        return View("Foo");
    }
}

View (snippet):

@using (Html.BeginForm("GetDocument", "Home", FormMethod.Post, new { enctype = "multipart/form-data" }))
{
    <input type="file" name="file" />
    <input type="submit" value="Upload File" />
}

How to add default value for html <textarea>?

You can use this.innerHTML.

_x000D_
_x000D_
<textarea name="message" rows = "10" cols = "100" onfocus="this.innerHTML=''"> Enter your message here... </textarea>
_x000D_
_x000D_
_x000D_

When text area is focused, it basically makes the innerHTML of the textarea an empty string.

How can I use external JARs in an Android project?

If using Android Studio, do the following (I've copied and modified @Vinayak Bs answer):

  1. Select the Project view in the Project sideview (instead of Packages or Android)
  2. Create a folder called libs in your project's root folder
  3. Copy your JAR files to the libs folder
  4. The sideview will be updated and the JAR files will show up in your project
  5. Now right click on each JAR file you want to import and then select "Add as Library...", which will include it in your project
  6. After that, all you need to do is reference the new classes in your code, eg. import javax.mail.*

How to add spacing between UITableViewCell

You will have to set frame to your image. Untested code is

cell.imageView.frame = CGRectOffset(cell.frame, 10, 10);

Java: Check the date format of current string is according to required format or not

For your case, you may use regex:

boolean checkFormat;

if (input.matches("([0-9]{2})/([0-9]{2})/([0-9]{4})"))
    checkFormat=true;
else
   checkFormat=false;

For a larger scope or if you want a flexible solution, refer to MadProgrammer's answer.

Edit

Almost 5 years after posting this answer, I realize that this is a stupid way to validate a date format. But i'll just leave this here to tell people that using regex to validate a date is unacceptable

Autoincrement VersionCode with gradle extra properties

A slightly tightened-up version of CommonsWare's excellent answer creates the version file if it doesn't exist:

def Properties versionProps = new Properties()
def versionPropsFile = file('version.properties')
if(versionPropsFile.exists())
    versionProps.load(new FileInputStream(versionPropsFile))
def code = (versionProps['VERSION_CODE'] ?: "0").toInteger() + 1
versionProps['VERSION_CODE'] = code.toString()
versionProps.store(versionPropsFile.newWriter(), null)

defaultConfig {
    versionCode code
    versionName "1.1"
    minSdkVersion 14
    targetSdkVersion 18
}

Find duplicate entries in a column

Try this query.. It uses the Analytic function SUM:

SELECT * FROM
(  
 SELECT SUM(1) OVER(PARTITION BY ctn_no) cnt, A.*
 FROM table1 a 
 WHERE s_ind ='Y'   
)
WHERE cnt > 2

Am not sure why you are identifying a record as a duplicate if the ctn_no repeats more than 2 times. FOr me it repeats more than once it is a duplicate. In this case change the las part of the query to WHERE cnt > 1

Auto margins don't center image in page

Whenever we don't add width and add margin:auto, I guess it will not work. It's from my experience. Width gives the idea where exactly it needs to provide equal margins.

How to re-sign the ipa file?

Kind of old question, but with the latest XCode, codesign is easy:

$ codesign -s my_certificate example.ipa 

$ codesign -vv example.ipa
example.ipa: valid on disk
example.ipa: satisfies its Designated Requirement

Converting Java objects to JSON with Jackson

To convert your object in JSON with Jackson:

ObjectWriter ow = new ObjectMapper().writer().withDefaultPrettyPrinter();
String json = ow.writeValueAsString(object);

GCC fatal error: stdio.h: No such file or directory

ubuntu users:

sudo apt-get install libc6-dev

specially ruby developers that have problem installing gem install json -v '1.8.2' on their VMs

How to replace NA values in a table for selected columns

Building on @Robert McDonald's tidyr::replace_na() answer, here are some dplyr options for controlling which columns the NAs are replaced:

library(tidyverse)

# by column type:
x %>%
  mutate_if(is.numeric, ~replace_na(., 0))

# select columns defined in vars(col1, col2, ...):
x %>%
  mutate_at(vars(a, b, c), ~replace_na(., 0))

# all columns:
x %>%
  mutate_all(~replace_na(., 0))

How to trigger event when a variable's value is changed?

The .NET framework actually provides an interface that you can use for notifying subscribers when a property has changed: System.ComponentModel.INotifyPropertyChanged. This interface has one event PropertyChanged. Its usually used in WPF for binding but I have found it useful in business layers as a way to standardize property change notification.

In terms of thread safety I would put a lock under in the setter so that you don't run into any race conditions.

Here are my thoughts in code :) :

public class MyClass : INotifyPropertyChanged
{
    private object _lock;

    public int MyProperty
    {
        get
        {
            return _myProperty;
        }
        set
        {
            lock(_lock)
            {
                //The property changed event will get fired whenever
                //the value changes. The subscriber will do work if the value is
                //1. This way you can keep your business logic outside of the setter
                if(value != _myProperty)
                {
                    _myProperty = value;
                    NotifyPropertyChanged("MyProperty");
                }
            }
        }
    }

    private NotifyPropertyChanged(string propertyName)
    {
        //Raise PropertyChanged event
    }
    public event PropertyChangedEventHandler PropertyChanged;
}


public class MySubscriber
{
    private MyClass _myClass;        

    void PropertyChangedInMyClass(object sender, PropertyChangedEventArgs e)
    {
        switch(e.PropertyName)
        {
            case "MyProperty":
                DoWorkOnMyProperty(_myClass.MyProperty);
                break;
        }
    }

    void DoWorkOnMyProperty(int newValue)
    {
        if(newValue == 1)
        {
             //DO WORK HERE
        }
    }
}

Hope this is helpful :)

Binding a generic list to a repeater - ASP.NET

Code Behind:

public class Friends
{
    public string   ID      { get; set; }
    public string   Name    { get; set; }
    public string   Image   { get; set; }
}

protected void Page_Load(object sender, EventArgs e)
{
        List <Friends> friendsList = new List<Friends>();

        foreach (var friend  in friendz)
        {
            friendsList.Add(
                new Friends { ID = friend.id, Name = friend.name }    
            );

        }

        this.rptFriends.DataSource = friendsList;
        this.rptFriends.DataBind();
}

.aspx Page

<asp:Repeater ID="rptFriends" runat="server">
            <HeaderTemplate>
                <table border="0" cellpadding="0" cellspacing="0">
                    <thead>
                        <tr>
                            <th>ID</th>
                            <th>Name</th>
                        </tr>
                    </thead>
                    <tbody>
            </HeaderTemplate>
            <ItemTemplate>
                    <tr>
                        <td><%# Eval("ID") %></td>
                        <td><%# Eval("Name") %></td>
                    </tr>
            </ItemTemplate>
            <FooterTemplate>
                    </tbody>
                </table>
            </FooterTemplate>
        </asp:Repeater>

Responsive table handling in Twitter Bootstrap

Bootstrap 3 now has Responsive tables out of the box. Hooray! :)

You can check it here: https://getbootstrap.com/docs/3.3/css/#tables-responsive

Add a <div class="table-responsive"> surrounding your table and you should be good to go:

<div class="table-responsive">
  <table class="table">
    ...
  </table>
</div>

To make it work on all layouts you can do this:

.table-responsive
{
    overflow-x: auto;
}

Selenium WebDriver How to Resolve Stale Element Reference Exception?

This worked for me (source here):

 /**
     * Attempts to click on an element multiple times (to avoid stale element
     * exceptions caused by rapid DOM refreshes)
     *
     * @param d
     *            The WebDriver
     * @param by
     *            By element locator
     */
    public static void dependableClick(WebDriver d, By by)
    {
        final int MAXIMUM_WAIT_TIME = 10;
        final int MAX_STALE_ELEMENT_RETRIES = 5;

        WebDriverWait wait = new WebDriverWait(d, MAXIMUM_WAIT_TIME);
        int retries = 0;
        while (true)
        {
            try
            {
                wait.until(ExpectedConditions.elementToBeClickable(by)).click();

                return;
            }
            catch (StaleElementReferenceException e)
            {
                if (retries < MAX_STALE_ELEMENT_RETRIES)
                {
                    retries++;
                    continue;
                }
                else
                {
                    throw e;
                }
            }
        }
    }

Calculating Covariance with Python and Numpy

When a and b are 1-dimensional sequences, numpy.cov(a,b)[0][1] is equivalent to your cov(a,b).

The 2x2 array returned by np.cov(a,b) has elements equal to

cov(a,a)  cov(a,b)

cov(a,b)  cov(b,b)

(where, again, cov is the function you defined above.)

String Concatenation in EL

Since Expression Language 3.0, it is valid to use += operator for string concatenation.

${(empty value)? "none" : value += " enabled"}  // valid as of EL 3.0

Quoting EL 3.0 Specification.

String Concatenation Operator

To evaluate

A += B 
  • Coerce A and B to String.
  • Return the concatenated string of A and B.

Edit and Continue: "Changes are not allowed when..."

If you're debugging an ASP.NET application, go to properties > web > Servers, and make sure that "enable and continue" is checked under Use Visual Studio Development Server.

Is there a Public FTP server to test upload and download?

I have found an FTP server and its working. I was successfully able to upload a file to this FTP server and then see file created by hitting same url. Visit here and read properly before use. Good luck...!

Edit: link is now dead, but the FTP server is still up! Connect with the username "anonymous" and an email address as a password: ftp://ftp.swfwmd.state.fl.us

BUT FIRST read this before using it

Unable to resolve host "<insert URL here>" No address associated with hostname

Please, check if you have valid internet connection.

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

Do something like this:

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

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

Then add this script:

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

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