Programs & Examples On #Partialfunction

Forcing label to flow inline with input that they label

<style>
.nowrap {
    white-space: nowrap;
}
</style>

...

<label for="id1" class="nowrap">label1:
    <input type="text" id="id1"/>
</label>

Wrap your inputs within the label tag

Ubuntu, how do you remove all Python 3 but not 2

Its simple just try: sudo apt-get remove python3.7 or the versions that you want to remove

Where is the correct location to put Log4j.properties in an Eclipse project?

This question is already answered here

The classpath never includes specific files. It includes directories and jar files. So, put that file in a directory that is in your classpath.

Log4j properties aren't (normally) used in developing apps (unless you're debugging Eclipse itself!). So what you really want to to build the executable Java app (Application, WAR, EAR or whatever) and include the Log4j properties in the runtime classpath.

How to debug Lock wait timeout exceeded on MySQL?

Due to the popularity of MySQL, there's no wonder Lock wait timeout exceeded; try restarting transaction exception gets so much attention on SO.

The more contention you have, the greater the chance of deadlocks, which a DB engine will resolve by time-outing one of the deadlocked transactions.

Also, long-running transactions that have modified (e.g. UPDATE or DELETE) a large number of entries are more likely to generate conflicts with other transactions.

Although InnoDB MVCC, you can still request explicit locks using the FOR UPDATE clause. However, unlike other popular DBs (Oracle, MSSQL, PostgreSQL, DB2), MySQL uses REPEATABLE_READ as the default isolation level.

Now, the locks that you acquired (either by modifying rows or using explicit locking), are held for the duration of the currently running transaction. If you want a good explanation of the difference between REPEATABLE_READ and READ COMMITTED in regards to locking, please read this Percona article.

In REPEATABLE READ every lock acquired during a transaction is held for the duration of the transaction.

In READ COMMITTED the locks that did not match the scan are released after the STATEMENT completes.

...

This means that in READ COMMITTED other transactions are free to update rows that they would not have been able to update (in REPEATABLE READ) once the UPDATE statement completes.

Therefore: The more restrictive the isolation level (REPEATABLE_READ, SERIALIZABLE) the greater the chance of deadlock. This is not an issue "per se", it's a trade-off.

You can get very good results with READ_COMMITED, as you need application-level lost update prevention when using logical transactions that span over multiple HTTP requests. The optimistic locking approach targets lost updates that might happen even if you use the SERIALIZABLE isolation level while reducing the lock contention by allowing you to use READ_COMMITED.

What are the differences between Abstract Factory and Factory design patterns?

To make it very simple with minimum interface & please focus "//1":

class FactoryProgram
    {
        static void Main()
        {
            object myType = Program.MyFactory("byte");
            Console.WriteLine(myType.GetType().Name);

            myType = Program.MyFactory("float"); //3
            Console.WriteLine(myType.GetType().Name);

            Console.ReadKey();
        }

        static object MyFactory(string typeName)
        {
            object desiredType = null; //1
            switch (typeName)
            {
                case "byte": desiredType = new System.Byte(); break; //2
                case "long": desiredType = new System.Int64(); break;
                case "float": desiredType = new System.Single(); break;
                default: throw new System.NotImplementedException();
            }
            return desiredType;
        }
    }

Here important points: 1. Factory & AbstractFactory mechanisms must use inheritance (System.Object-> byte, float ...); so if you have inheritance in program then Factory(Abstract Factory would not be there most probably) is already there by design 2. Creator (MyFactory) knows about concrete type so returns concrete type object to caller(Main); In abstract factory return type would be an Interface.

interface IVehicle { string VehicleName { get; set; } }
interface IVehicleFactory
    {
        IVehicle CreateSingleVehicle(string vehicleType);
    }
class HondaFactory : IVehicleFactory
    {
        public IVehicle CreateSingleVehicle(string vehicleType)
        {
            switch (vehicleType)
            {
                case "Sports": return new SportsBike();
                case "Regular":return new RegularBike();
                default: throw new ApplicationException(string.Format("Vehicle '{0}' cannot be created", vehicleType));
            }
        }
    }
class HeroFactory : IVehicleFactory
    {
        public IVehicle CreateSingleVehicle(string vehicleType)
        {
            switch (vehicleType)
            {
                case "Sports":  return new SportsBike();
                case "Scooty": return new Scooty();
                case "DarkHorse":return new DarkHorseBike();
                default: throw new ApplicationException(string.Format("Vehicle '{0}' cannot be created", vehicleType));
            }
        }
    }

class RegularBike : IVehicle { public string VehicleName { get { return "Regular Bike- Name"; } set { VehicleName = value; } } }
class SportsBike : IVehicle { public string VehicleName { get { return "Sports Bike- Name"; } set { VehicleName = value; } } }
class RegularScooter : IVehicle { public string VehicleName { get { return "Regular Scooter- Name"; } set { VehicleName = value; } } }
class Scooty : IVehicle { public string VehicleName { get { return "Scooty- Name"; } set { VehicleName = value; } } }
class DarkHorseBike : IVehicle { public string VehicleName { get { return "DarkHorse Bike- Name"; } set { VehicleName = value; } } }

class Program
{
    static void Main(string[] args)
    {
        IVehicleFactory honda = new HondaFactory(); //1
        RegularBike hondaRegularBike = (RegularBike)honda.CreateSingleVehicle("Regular"); //2
        SportsBike hondaSportsBike = (SportsBike)honda.CreateSingleVehicle("Sports");
        Console.WriteLine("******* Honda **********"+hondaRegularBike.VehicleName+ hondaSportsBike.VehicleName);

        IVehicleFactory hero = new HeroFactory();
        DarkHorseBike heroDarkHorseBike = (DarkHorseBike)hero.CreateSingleVehicle("DarkHorse");
        SportsBike heroSportsBike = (SportsBike)hero.CreateSingleVehicle("Sports");
        Scooty heroScooty = (Scooty)hero.CreateSingleVehicle("Scooty");
        Console.WriteLine("******* Hero **********"+heroDarkHorseBike.VehicleName + heroScooty.VehicleName+ heroSportsBike.VehicleName);

        Console.ReadKey();
    }
}

Important points: 1. Requirement: Honda would create "Regular", "Sports" but Hero would create "DarkHorse", "Sports" and "Scooty". 2. why two interfaces? One for manufacturer type(IVehicleFactory) and another for product factory(IVehicle); other way to understand 2 interfaces is abstract factory is all about creating related objects 2. The catch is the IVehicleFactory's children returning and IVehicle(instead of concrete in factory); so I get parent variable(IVehicle); then I create actual concrete type by calling CreateSingleVehicle and then casting parent object to actual child object. What would happen if I do RegularBike heroRegularBike = (RegularBike)hero.CreateSingleVehicle("Regular");; you will get ApplicationException and that's why we need generic abstract factory which I would explain if required. Hope it helps from beginner to intermediate audience.

How do I print uint32_t and uint16_t variables value?

The macros defined in <inttypes.h> are the most correct way to print values of types uint32_t, uint16_t, and so forth -- but they're not the only way.

Personally, I find those macros difficult to remember and awkward to use. (Given the syntax of a printf format string, that's probably unavoidable; I'm not claiming I could have come up with a better system.)

An alternative is to cast the values to a predefined type and use the format for that type.

Types int and unsigned int are guaranteed by the language to be at least 16 bits wide, and therefore to be able to hold any converted value of type int16_t or uint16_t, respectively. Similarly, long and unsigned long are at least 32 bits wide, and long long and unsigned long long are at least 64 bits wide.

For example, I might write your program like this (with a few additional tweaks):

#include <stdio.h>
#include <stdint.h>
#include <netinet/in.h>  

int main(void)
{
    uint32_t a=12, a1;
    uint16_t b=1, b1;
    a1 = htonl(a);
    printf("%lu---------%lu\n", (unsigned long)a, (unsigned long)a1);
    b1 = htons(b);
    printf("%u-----%u\n", (unsigned)b, (unsigned)b1);
    return 0;
}

One advantage of this approach is that it can work even with pre-C99 implementations that don't support <inttypes.h>. Such an implementation most likely wouldn't have <stdint.h> either, but the technique is useful for other integer types.

Sort matrix according to first column in R

If your data is in a matrix named foo, the line you would run is

foo.sorted=foo[order[foo[,1]]

How to pass arguments to a Button command in Tkinter?

button = Tk.Button(master=frame, text='press', command=lambda: action(someNumber))

I believe should fix this

Fetching distinct values on a column using Spark DataFrame

Well to obtain all different values in a Dataframe you can use distinct. As you can see in the documentation that method returns another DataFrame. After that you can create a UDF in order to transform each record.

For example:

val df = sc.parallelize(Array((1, 2), (3, 4), (1, 6))).toDF("age", "salary")

// I obtain all different values. If you show you must see only {1, 3}
val distinctValuesDF = df.select(df("age")).distinct

// Define your udf. In this case I defined a simple function, but they can get complicated.
val myTransformationUDF = udf(value => value / 10)

// Run that transformation "over" your DataFrame
val afterTransformationDF = distinctValuesDF.select(myTransformationUDF(col("age")))

Bash function to find newest file matching pattern

The combination of find and ls works well for

  • filenames without newlines
  • not very large amount of files
  • not very long filenames

The solution:

find . -name "my-pattern" -print0 |
    xargs -r -0 ls -1 -t |
    head -1

Let's break it down:

With find we can match all interesting files like this:

find . -name "my-pattern" ...

then using -print0 we can pass all filenames safely to the ls like this:

find . -name "my-pattern" -print0 | xargs -r -0 ls -1 -t

additional find search parameters and patterns can be added here

find . -name "my-pattern" ... -print0 | xargs -r -0 ls -1 -t

ls -t will sort files by modification time (newest first) and print it one at a line. You can use -c to sort by creation time. Note: this will break with filenames containing newlines.

Finally head -1 gets us the first file in the sorted list.

Note: xargs use system limits to the size of the argument list. If this size exceeds, xargs will call ls multiple times. This will break the sorting and probably also the final output. Run

xargs  --show-limits

to check the limits on you system.

Note 2: use find . -maxdepth 1 -name "my-pattern" -print0 if you don't want to search files through subfolders.

Note 3: As pointed out by @starfry - -r argument for xargs is preventing the call of ls -1 -t, if no files were matched by the find. Thank you for the suggesion.

How can I count the occurrences of a list item?

l2=[1,"feto",["feto",1,["feto"]],['feto',[1,2,3,['feto']]]]
count=0
 def Test(l):   
        global count 
        if len(l)==0:
             return count
        count=l.count("feto")
        for i in l:
             if type(i) is list:
                count+=Test(i)
        return count   
    print(Test(l2))

this will recursive count or search for the item in the list even if it in list of lists

CodeIgniter: "Unable to load the requested class"

I had a similar issue when deploying from OSx on my local to my Linux live site.

It ran fine on OSx, but on Linux I was getting:

An Error Was Encountered

Unable to load the requested class: Ckeditor

The problem was that Linux paths are apparently case-sensitive so I had to rename my library files from "ckeditor.php" to "CKEditor.php".

I also changed my load call to match the capitalization:

$this->load->library('CKEditor');

java.io.IOException: Could not locate executable null\bin\winutils.exe in the Hadoop binaries. spark Eclipse on windows 7

You can alternatively download winutils.exe from GITHub:

https://github.com/steveloughran/winutils/tree/master/hadoop-2.7.1/bin

replace hadoop-2.7.1 with the version you want and place the file in D:\hadoop\bin

If you do not have access rights to the environment variable settings on your machine, simply add the below line to your code:

System.setProperty("hadoop.home.dir", "D:\\hadoop");

How does the communication between a browser and a web server take place?

Hyper Text Transfer Protocol (HTTP) is a protocol used for transferring web pages (like the one you're reading right now). A protocol is really nothing but a standard way of doing things. If you were to meet the President of the United States, or the king of a country, there would be specific procedures that you'd have to follow. You couldn't just walk up and say "hey dude". There would be a specific way to walk, to talk, a standard greeting, and a standard way to end the conversation. Protocols in the TCP/IP stack serve the same purpose.

The TCP/IP stack has four layers: Application, Transport, Internet, and Network. At each layer there are different protocols that are used to standardize the flow of information, and each one is a computer program (running on your computer) that's used to format the information into a packet as it's moving down the TCP/IP stack. A packet is a combination of the Application Layer data, the Transport Layer header (TCP or UDP), and the IP layer header (the Network Layer takes the packet and turns it into a frame).

The Application Layer

...consists of all applications that use the network to transfer data. It does not care about how the data gets between two points and it knows very little about the status of the network. Applications pass data to the next layer in the TCP/IP stack and then continue to perform other functions until a reply is received. The Application Layer uses host names (like www.dalantech.com) for addressing. Examples of application layer protocols: Hyper Text Transfer Protocol (HTTP -web browsing), Simple Mail Transfer Protocol (SMTP -electronic mail), Domain Name Services (DNS -resolving a host name to an IP address), to name just a few.

The main purpose of the Application Layer is to provide a common command language and syntax between applications that are running on different operating systems -kind of like an interpreter. The data that is sent by an application that uses the network is formatted to conform to one of several set standards. The receiving computer can understand the data that is being sent even if it is running a different operating system than the sender due to the standards that all network applications conform to.

The Transport Layer

...is responsible for assigning source and destination port numbers to applications. Port numbers are used by the Transport Layer for addressing and they range from 1 to 65,535. Port numbers from 0 to 1023 are called "well known ports". The numbers below 256 are reserved for public (standard) services that run at the Application Layer. Here are a few: 25 for SMTP, 53 for DNS (udp for domain resolution and tcp for zone transfers) , and 80 for HTTP. The port numbers from 256 to 1023 are assigned by the IANA to companies for the applications that they sell.

Port numbers from 1024 to 65,535 are used for client side applications -the web browser you are using to read this page, for example. Windows will only assign port numbers up to 5000 -more than enough port numbers for a Windows based PC. Each application has a unique port number assigned to it by the transport layer so that as data is received by the Transport Layer it knows which application to give the data to. An example is when you have more than one browser window running. Each window is a separate instance of the program that you use to surf the web, and each one has a different port number assigned to it so you can go to www.dalantech.com in one browser window and this site does not load into another browser window. Applications like FireFox that use tabbed windows simply have a unique port number assigned to each tab

The Internet Layer

...is the "glue" that holds networking together. It permits the sending, receiving, and routing of data.

The Network Layer

...consists of your Network Interface Card (NIC) and the cable connected to it. It is the physical medium that is used to transmit and receive data. The Network Layer uses Media Access Control (MAC) addresses, discussed earlier, for addressing. The MAC address is fixed at the time an interface was manufactured and cannot be changed. There are a few exceptions, like DSL routers that allow you to clone the MAC address of the NIC in your PC.

For more info:

multiple ways of calling parent method in php

Unless I am misunderstanding the question, I would almost always use $this->get_species because the subclass (in this case dog) could overwrite that method since it does extend it. If the class dog doesn't redefine the method then both ways are functionally equivalent but if at some point in the future you decide you want the get_species method in dog should print "dog" then you would have to go back through all the code and change it.

When you use $this it is actually part of the object which you created and so will always be the most up-to-date as well (if the property being used has changed somehow in the lifetime of the object) whereas using the parent class is calling the static class method.

Converting JavaScript object with numeric keys into array

Using raw javascript, suppose you have:

var j = {0: "1", 1: "2", 2: "3", 3: "4"};

You could get the values with:

Object.keys(j).map(function(_) { return j[_]; })

Output:

["1", "2", "3", "4"]

Why is “while ( !feof (file) )” always wrong?

feof() indicates if one has tried to read past the end of file. That means it has little predictive effect: if it is true, you are sure that the next input operation will fail (you aren't sure the previous one failed BTW), but if it is false, you aren't sure the next input operation will succeed. More over, input operations may fail for other reasons than the end of file (a format error for formatted input, a pure IO failure -- disk failure, network timeout -- for all input kinds), so even if you could be predictive about the end of file (and anybody who has tried to implement Ada one, which is predictive, will tell you it can complex if you need to skip spaces, and that it has undesirable effects on interactive devices -- sometimes forcing the input of the next line before starting the handling of the previous one), you would have to be able to handle a failure.

So the correct idiom in C is to loop with the IO operation success as loop condition, and then test the cause of the failure. For instance:

while (fgets(line, sizeof(line), file)) {
    /* note that fgets don't strip the terminating \n, checking its
       presence allow to handle lines longer that sizeof(line), not showed here */
    ...
}
if (ferror(file)) {
   /* IO failure */
} else if (feof(file)) {
   /* format error (not possible with fgets, but would be with fscanf) or end of file */
} else {
   /* format error (not possible with fgets, but would be with fscanf) */
}

Laravel - htmlspecialchars() expects parameter 1 to be string, object given

Laravel - htmlspecialchars() expects parameter 1 to be string, object given.

thank me latter.........................

when you send or get array from contrller or function but try to print as single value or single variable in laravel blade file so it throws an error

->use any think who convert array into string it work.

solution: 1)run the foreach loop and get single single value and print. 2)The implode() function returns a string from the elements of an array. {{ implode($your_variable,',') }}

implode is best way to do it and its 100% work.

Angular JS update input field after change

I wrote a directive you can use to bind an ng-model to any expression you want. Whenever the expression changes the model is set to the new value.

 module.directive('boundModel', function() {
      return {
        require: 'ngModel',
        link: function(scope, elem, attrs, ngModel) {
          var boundModel$watcher = scope.$watch(attrs.boundModel, function(newValue, oldValue) {
            if(newValue != oldValue) {
              ngModel.$setViewValue(newValue);
              ngModel.$render();
            }
          });

          // When $destroy is fired stop watching the change.
          // If you don't, and you come back on your state
          // you'll have two watcher watching the same properties
          scope.$on('$destroy', function() {
              boundModel$watcher();
          });
        }
    });

You can use it in your templates like this:

 <li>Total<input type="text" ng-model="total" bound-model="one * two"></li>      

Docker: "no matching manifest for windows/amd64 in the manifest list entries"

The reason it is showing this message because it is unable to find Linux containers as running. So, make sure you switch from windows to linux containers before running it.

Disable validation of HTML5 form elements

I had a read of the spec and did some testing in Chrome, and if you catch the "invalid" event and return false that seems to allow form submission.

I am using jquery, with this HTML.

_x000D_
_x000D_
// suppress "invalid" events on URL inputs_x000D_
$('input[type="url"]').bind('invalid', function() {_x000D_
  alert('invalid');_x000D_
  return false;_x000D_
});_x000D_
_x000D_
document.forms[0].onsubmit = function () {_x000D_
  alert('form submitted');_x000D_
};
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<form>_x000D_
  <input type="url" value="http://" />_x000D_
  <button type="submit">Submit</button>_x000D_
</form>
_x000D_
_x000D_
_x000D_

I haven't tested this in any other browsers.

CSS two divs next to each other

just use a z-index and everything will sit nice. make sure to have positions marked as fixed or absolute. then nothing will move around like with a float tag.

How to overcome root domain CNAME restrictions?

You have to put a period at the end of the external domain so it doesn't think you mean customer1.mycompanydomain.com.localdomain;

So just change:

customer1.com IN CNAME customer1.mycompanydomain.com

To

customer1.com IN CNAME customer1.mycompanydomain.com.

MVC3 EditorFor readOnly

For those who wonder why you want to use an EditoFor if you don`t want it to be editable, I have an example.

I have this in my Model.

    [DataType(DataType.Date)]
    [DisplayFormat(ApplyFormatInEditMode = true, DataFormatString = "{0: dd/MM/yyyy}")]
    public DateTime issueDate { get; set; }

and when you want to display that format, the only way it works is with an EditorFor, but I have a jquery datepicker for that "input" so it has to be readonly to avoid the users of writting down wrong dates.

To make it work the way I want I put this in the View...

     @Html.EditorFor(m => m.issueDate, new{ @class="inp", @style="width:200px", @MaxLength = "200"})

and this in my ready function...

     $('#issueDate').prop('readOnly', true);

I hope this would be helpful for someone out there. Sorry for my English

Control cannot fall through from one case label

Since it wasn't mentioned in the other answers, I'd like to add that if you want case SearchAuthors to be executed right after the first case, just like omitting the break in some other programming languages where that is allowed, you can simply use goto.

switch (searchType)
{
    case "SearchBooks":
    Selenium.Type("//*[@id='SearchBooks_TextInput']", searchText);
    Selenium.Click("//*[@id='SearchBooks_SearchBtn']");
    goto case "SearchAuthors";

    case "SearchAuthors":
    Selenium.Type("//*[@id='SearchAuthors_TextInput']", searchText);
    Selenium.Click("//*[@id='SearchAuthors_SearchBtn']");
    break;
}

How to pass parameters to ThreadStart method in Thread?

The simplest is just

string filename = ...
Thread thread = new Thread(() => download(filename));
thread.Start();

The advantage(s) of this (over ParameterizedThreadStart) is that you can pass multiple parameters, and you get compile-time checking without needing to cast from object all the time.

Resize UIImage and change the size of UIImageView

This is the Swift equivalent for Rajneesh071's answer, using extensions

UIImage {
  func scaleToSize(aSize :CGSize) -> UIImage {
    if (CGSizeEqualToSize(self.size, aSize)) {
      return self
    }

    UIGraphicsBeginImageContextWithOptions(aSize, false, 0.0)
    self.drawInRect(CGRectMake(0.0, 0.0, aSize.width, aSize.height))
    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    return image
  }
}

Usage:

let image = UIImage(named: "Icon")
item.icon = image?.scaleToSize(CGSize(width: 30.0, height: 30.0))

SQLite add Primary Key

As long as you are using CREATE TABLE, if you are creating the primary key on a single field, you can use:

CREATE TABLE mytable (
field1 TEXT,
field2 INTEGER PRIMARY KEY,
field3 BLOB,
);

With CREATE TABLE, you can also always use the following approach to create a primary key on one or multiple fields:

CREATE TABLE mytable (
field1 TEXT,
field2 INTEGER,
field3 BLOB,
PRIMARY KEY (field2, field1)
);

Reference: http://www.sqlite.org/lang_createtable.html

This answer does not address table alteration.

git index.lock File exists when I try to commit, but cannot delete the file

On Linux, Unix, Git Bash, or Cygwin, try:

rm -f .git/index.lock

On Windows Command Prompt, try:

del .git\index.lock


For Windows:

  • From a PowerShell console opened as administrator, try

    rm -Force ./.git/index.lock
    
  • If that does not work, you must kill all git.exe processes

    taskkill /F /IM git.exe
    

    SUCCESS: The process "git.exe" with PID 20448 has been terminated.
    SUCCESS: The process "git.exe" with PID 11312 has been terminated.
    SUCCESS: The process "git.exe" with PID 23868 has been terminated.
    SUCCESS: The process "git.exe" with PID 27496 has been terminated.
    SUCCESS: The process "git.exe" with PID 33480 has been terminated.
    SUCCESS: The process "git.exe" with PID 28036 has been terminated. \

    rm -Force ./.git/index.lock
    

Returning Month Name in SQL Server Query

Without hitting db we can fetch all months name.

WITH CTE_Sample1 AS
(
    Select 0 as MonthNumber

    UNION ALL

    select MonthNumber+1 FROM CTE_Sample1
        WHERE MonthNumber+1<12
)

Select DateName( month , DateAdd( month , MonthNumber ,0 ) ) from CTE_Sample1

How to convert a HTMLElement to a string

The element outerHTML property (note: supported by Firefox after version 11) returns the HTML of the entire element.

Example

<div id="new-element-1">Hello world.</div>

<script type="text/javascript"><!--

var element = document.getElementById("new-element-1");
var elementHtml = element.outerHTML;
// <div id="new-element-1">Hello world.</div>

--></script>

Similarly, you can use innerHTML to get the HTML contained within a given element, or innerText to get the text inside an element (sans HTML markup).

See Also

  1. outerHTML - Javascript Property
  2. Javascript Reference - Elements

What is the { get; set; } syntax in C#?

This mean that if you create a variable of type Genre, you will be able to access the variable as a property

Genre oG = new Genre();
oG.Name = "Test";

What is the non-jQuery equivalent of '$(document).ready()'?

Now that it's 2018 here's a quick and simple method.

This will add an event listener, but if it already fired we'll check that the dom is in a ready state or that it's complete. This can fire before or after sub-resources have finished loading (images, stylesheets, frames, etc).

_x000D_
_x000D_
function domReady(fn) {_x000D_
  // If we're early to the party_x000D_
  document.addEventListener("DOMContentLoaded", fn);_x000D_
  // If late; I mean on time._x000D_
  if (document.readyState === "interactive" || document.readyState === "complete" ) {_x000D_
    fn();_x000D_
  }_x000D_
}_x000D_
_x000D_
domReady(() => console.log("DOM is ready, come and get it!"));
_x000D_
_x000D_
_x000D_

Additional Readings


Update

Here's some quick utility helpers using standard ES6 Import & Export I wrote that include TypeScript as well. Maybe I can get around to making these a quick library that can be installed into projects as a dependency.

JavaScript

export const domReady = (callBack) => {
  if (document.readyState === "loading") {
    document.addEventListener('DOMContentLoaded', callBack);
  }
  else {
    callBack();
  }
}

export const windowReady = (callBack) => {
  if (document.readyState === 'complete') {
    callBack();
  }
  else {
    window.addEventListener('load', callBack);
  }
}

TypeScript

export const domReady = (callBack: () => void) => {
  if (document.readyState === "loading") {
    document.addEventListener('DOMContentLoaded', callBack);
  }
  else {
    callBack();
  }
}

export const windowReady = (callBack: () => void) => {
  if (document.readyState === 'complete') {
    callBack();
  }
  else {
    window.addEventListener('load', callBack);
  }
}

Promises

export const domReady = new Promise(resolve => {
  if (document.readyState === "loading") {
    document.addEventListener('DOMContentLoaded', resolve);
  }
  else {
    resolve();
  }
});

export const windowReady = new Promise(resolve => {
  if (document.readyState === 'complete') {
    resolve();
  }
  else {
    window.addEventListener('load', resolve);
  }
});

How can I print message in Makefile?

It's not clear what you want, or whether you want this trick to work with different targets, or whether you've defined these targets elsewhere, or what version of Make you're using, but what the heck, I'll go out on a limb:

ifeq (yes, ${TEST})
CXXFLAGS := ${CXXFLAGS} -DDESKTOP_TEST
test:
$(info ************  TEST VERSION ************)
else
release:
$(info ************ RELEASE VERSIOIN **********)
endif

how to add the missing RANDR extension

I am seeing this error message when I run Firefox headless through selenium using xvfb. It turns out that the message was a red herring for me. The message is only a warning, not an error. It is not why Firefox was not starting correctly.

The reason that Firefox was not starting for me was that it had been updated to a version that was no longer compatible with the Selenium drivers that I was using. I upgraded the selenium drivers to the latest and Firefox starts up fine again (even with this warning message about RANDR).

New releases of Firefox are often only compatible with one or two versions of Selenium. Occasionally Firefox is released with NO compatible version of Selenium. When that happens, it may take a week or two for a new version of Selenium to get released. Because of this, I now keep a version of Firefox that is known to work with the version of Selenium that I have installed. In addition to the version of Firefox that is kept up to date by my package manager, I have a version installed in /opt/ (eg /opt/firefox31/). The Selenium Java API takes an argument for the location of the Firefox binary to be used. The downside is that older versions of Firefox have known security vulnerabilities and shouldn't be used with untrusted content.

How to use vagrant in a proxy environment?

If you actually do want your proxy configurations and plugin installations to be in your Vagrantfile, for example if you're making a Vagrantfile just for your corporate environment and can't have users editing environment variables, this was the answer for me:

ENV['http_proxy']  = 'http://proxyhost:proxyport'
ENV['https_proxy'] = 'http://proxyhost:proxyport'

# Plugin installation procedure from http://stackoverflow.com/a/28801317
required_plugins = %w(vagrant-proxyconf)

plugins_to_install = required_plugins.select { |plugin| not Vagrant.has_plugin? plugin }
if not plugins_to_install.empty?
  puts "Installing plugins: #{plugins_to_install.join(' ')}"
  if system "vagrant plugin install #{plugins_to_install.join(' ')}"
    exec "vagrant #{ARGV.join(' ')}"
  else
    abort "Installation of one or more plugins has failed. Aborting."
  end
end

Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
  config.proxy.http     = "#{ENV['http_proxy']}"
  config.proxy.https    = "#{ENV['https_proxy']}"
  config.proxy.no_proxy = "localhost,127.0.0.1"
  # and so on

(If you don't, just set them as environment variables like the other answers say and refer to them from env in config.proxy.http(s) directives.)

What is Dispatcher Servlet in Spring?

I know this question is marked as solved already but I want to add a newer image explaining this pattern in detail(source: spring in action 4):

enter image description here

Explanation

When the request leaves the browser (1), it carries information about what the user is asking for. At the least, the request will be carrying the requested URL. But it may also carry additional data, such as the information submitted in a form by the user.

The first stop in the request’s travels is at Spring’s DispatcherServlet. Like most Java- based web frameworks, Spring MVC funnels requests through a single front controller servlet. A front controller is a common web application pattern where a single servlet delegates responsibility for a request to other components of an application to per- form actual processing. In the case of Spring MVC, DispatcherServlet is the front controller. The DispatcherServlet’s job is to send the request on to a Spring MVC controller. A controller is a Spring component that processes the request. But a typical application may have several controllers, and DispatcherServlet needs some help deciding which controller to send the request to. So the DispatcherServlet consults one or more handler mappings (2) to figure out where the request’s next stop will be. The handler mapping pays particular attention to the URL carried by the request when making its decision. Once an appropriate controller has been chosen, DispatcherServlet sends the request on its merry way to the chosen controller (3). At the controller, the request drops off its payload (the information submitted by the user) and patiently waits while the controller processes that information. (Actually, a well-designed controller per- forms little or no processing itself and instead delegates responsibility for the business logic to one or more service objects.) The logic performed by a controller often results in some information that needs to be carried back to the user and displayed in the browser. This information is referred to as the model. But sending raw information back to the user isn’t suffi- cient—it needs to be formatted in a user-friendly format, typically HTML. For that, the information needs to be given to a view, typically a JavaServer Page (JSP). One of the last things a controller does is package up the model data and identify the name of a view that should render the output. It then sends the request, along with the model and view name, back to the DispatcherServlet (4). So that the controller doesn’t get coupled to a particular view, the view name passed back to DispatcherServlet doesn’t directly identify a specific JSP. It doesn’t even necessarily suggest that the view is a JSP. Instead, it only carries a logical name that will be used to look up the actual view that will produce the result. The DispatcherServlet consults a view resolver (5) to map the logical view name to a spe- cific view implementation, which may or may not be a JSP. Now that DispatcherServlet knows which view will render the result, the request’s job is almost over. Its final stop is at the view implementation (6), typically a JSP, where it delivers the model data. The request’s job is finally done. The view will use the model data to render output that will be carried back to the client by the (not- so-hardworking) response object (7).

"Non-resolvable parent POM: Could not transfer artifact" when trying to refer to a parent pom from a child pom with ${parent.groupid}

As Nayan said the Path has to updated properly in my case the apache-maven was installed in C:\apache-maven and settings.xml was found inside C:\apache-maven\conf\settings.xml

if this doesn't work go to your local repos
in my case C:\Users\<<"name">>.m2\
and search for .lastUpdated and delete them
then build the maven

NoClassDefFoundError: org/slf4j/impl/StaticLoggerBinder

Add the all tiles jars like(tiles-jsp,tiles-servlet,tiles-template,tiles-extras.tiles-core ) to your server lib folder and your application build path then it work if you using apache tailes with spring mvc application

Get column value length, not column max length of value

LENGTH() does return the string length (just verified). I suppose that your data is padded with blanks - try

SELECT typ, LENGTH(TRIM(t1.typ))
FROM AUTA_VIEW t1;

instead.

As OraNob mentioned, another cause could be that CHAR is used in which case LENGTH() would also return the column width, not the string length. However, the TRIM() approach also works in this case.

List of enum values in java

tl;dr

Can you make and edit a collection of objects from an enum? Yes.

If you do not care about the order, use EnumSet, an implementation of Set.

enum Animal{ DOG , CAT , BIRD , BAT ; }

Set<Animal> flyingAnimals = EnumSet.of( BIRD , BAT );

Set<Animal> featheredFlyingAnimals = flyingAnimals.clone().remove( BAT ) ;

If you care about order, use a List implementation such as ArrayList. For example, we can create a list of a person’s preference in choosing a pet, in the order of their most preferred.

List< Animal > favoritePets = new ArrayList<>() ;
favoritePets.add( CAT ) ;  // This person prefers cats over dogs…
favoritePets.add( DOG ) ;  // …but would accept either.
                           // This person would not accept a bird nor a bat.

For a non-modifiable ordered list, use List.of.

List< Animal > favoritePets = List.of( CAT , DOG ) ;  // This person prefers cats over dogs, but would accept either. This person would not accept a bird nor a bat. 

Details

The Answer (EnumSet) by Amit Deshpande and the Answer (.values) by Marko Topolnik are both correct. Here is a bit more info.

Enum.values

The .values() method is an implicitly declared method on Enum, added by the compiler. It produces a crude array rather than a Collection. Certainly usable.

Special note about documentation: Being unusual as an implicitly declared method, the .values() method is not listed among the methods on the Enum class. The method is defined in the Java Language Specification, and is mentioned in the doc for Enum.valueOf.

EnumSet – Fast & Small

The upsides to EnumSet include:

  • Extreme speed.
  • Compact use of memory.

To quote the class doc:

Enum sets are represented internally as bit vectors. This representation is extremely compact and efficient. The space and time performance of this class should be good enough to allow its use as a high-quality, typesafe alternative to traditional int-based "bit flags." Even bulk operations (such as containsAll and retainAll) should run very quickly if their argument is also an enum set.

Given this enum:

enum Animal
{
    DOG , CAT , BIRD , BAT ;
}

Make an EnumSet in one line.

Set<Animal> allAnimals = EnumSet.allOf( Animal.class );

Dump to console.

System.out.println( "allAnimals : " + allAnimals );

allAnimals : [DOG, CAT, BIRD, BAT]

Make a set from a subset of the enum objects.

Set<Animal> flyingAnimals = EnumSet.of( BIRD , BAT );

Look at the class doc to see many ways to manipulate the collection including adding or removing elements.

Set<Animal> featheredFlyingAnimals = 
    EnumSet.copyOf( flyingAnimals ).remove( BAT );

Natural Order

The doc promises the Iterator for EnumSet is in natural order, the order in which the values of the enum were originally declared.

To quote the class doc:

The iterator returned by the iterator method traverses the elements in their natural order (the order in which the enum constants are declared).

Frankly, given this promise, I'm confused why this is not a SortedSet. But, oh well, good enough. We can create a List from the Set if desired. Pass any Collection to constructor of ArrayList and that collection’s Iterator is automatically called on your behalf.

List<Animal> list = new ArrayList<>( allAnimals );

Dump to console.

System.out.println("list : " + list );

When run.

list : [DOG, CAT, BIRD, BAT]

In Java 10 and later, you can conveniently create a non-modifiable List by passing the EnumSet. The order of the new list will be in the iterator order of the EnumSet. The iterator order of an EnumSet is the order in which the element objects of the enum were defined on that enum.

List< Animal > nonModList = List.copyOf( allAnimals ) ;  // Or pass Animals.values() 

Discard all and get clean copy of latest revision?

hg status will show you all the new files, and then you can just rm them.

Normally I want to get rid of ignored and unversioned files, so:

hg status -iu                          # to show 
hg status -iun0 | xargs -r0 rm         # to destroy

And then follow that with:

hg update -C -r xxxxx

which puts all the versioned files in the right state for revision xxxx


To follow the Stack Overflow tradition of telling you that you don't want to do this, I often find that this "Nuclear Option" has destroyed stuff I care about.

The right way to do it is to have a 'make clean' option in your build process, and maybe a 'make reallyclean' and 'make distclean' too.

How to Convert UTC Date To Local time Zone in MySql Select Query

 select convert_tz(now(),@@session.time_zone,'+05:30')

replace '+05:30' with desired timezone. see here - https://stackoverflow.com/a/3984412/2359994

to format into desired time format, eg:

 select DATE_FORMAT(convert_tz(now(),@@session.time_zone,'+05:30') ,'%b %d %Y %h:%i:%s %p') 

you will get similar to this -> Dec 17 2014 10:39:56 AM

Ascending and Descending Number Order in java

Three possible solutions come to my mind:

1. Reverse the order:

//convert the arr to list first
Collections.reverse(listWithNumbers);
System.out.print("Numbers in Descending Order: " + listWithNumbers);

2. Iterate backwards and print it:

Arrays.sort(arr);
System.out.print("Numbers in Descending Order: " );
for(int i = arr.length - 1; i >= 0; i--){
  System.out.print( " " +arr[i]);
}

3. Sort it with "oposite" comparator:

Arrays.sort(arr, new Comparator<Integer>(){
   int compare(Integer i1, Integer i2) {
      return i2 - i1;
   }
});
// or Collections.reverseOrder(), could be used instead
System.out.print("Numbers in Descending Order: " );
for(int i = 0; i < arr.length; i++){
  System.out.print( " " +arr[i]);
}

how do I initialize a float to its max/min value?

You can either use -FLT_MAX (or -DBL_MAX) for the maximum magnitude negative number and FLT_MAX (or DBL_MAX) for positive. This gives you the range of possible float (or double) values.

You probably don't want to use FLT_MIN; it corresponds to the smallest magnitude positive number that can be represented with a float, not the most negative value representable with a float.

FLT_MIN and FLT_MAX correspond to std::numeric_limits<float>::min() and std::numeric_limits<float>::max().

Exception thrown inside catch block - will it be caught again?

As said above...
I would add that if you have trouble seeing what is going on, if you can't reproduce the issue in the debugger, you can add a trace before re-throwing the new exception (with the good old System.out.println at worse, with a good log system like log4j otherwise).

Java Map equivalent in C#

Dictionary<,> is the equivalent. While it doesn't have a Get(...) method, it does have an indexed property called Item which you can access in C# directly using index notation:

class Test {
  Dictionary<int,String> entities;

  public String getEntity(int code) {
    return this.entities[code];
  }
}

If you want to use a custom key type then you should consider implementing IEquatable<> and overriding Equals(object) and GetHashCode() unless the default (reference or struct) equality is sufficient for determining equality of keys. You should also make your key type immutable to prevent weird things happening if a key is mutated after it has been inserted into a dictionary (e.g. because the mutation caused its hash code to change).

How to add an item to a drop down list in ASP.NET?

Try following code;

DropDownList1.Items.Add(new ListItem(txt_box1.Text));

VBA Macro to compare all cells of two Excel files

Do NOT loop through all cells!! There is a lot of overhead in communications between worksheets and VBA, for both reading and writing. Looping through all cells will be agonizingly slow. I'm talking hours.

Instead, load an entire sheet at once into a Variant array. In Excel 2003, this takes about 2 seconds (and 250 MB of RAM). Then you can loop through it in no time at all.

In Excel 2007 and later, sheets are about 1000 times larger (1048576 rows × 16384 columns = 17 billion cells, compared to 65536 rows × 256 columns = 17 million in Excel 2003). You will run into an "Out of memory" error if you try to load the whole sheet into a Variant; on my machine I can only load 32 million cells at once. So you have to limit yourself to the range you know has actual data in it, or load the sheet bit by bit, e.g. 30 columns at a time.

Option Explicit

Sub test()

    Dim varSheetA As Variant
    Dim varSheetB As Variant
    Dim strRangeToCheck As String
    Dim iRow As Long
    Dim iCol As Long

    strRangeToCheck = "A1:IV65536"
    ' If you know the data will only be in a smaller range, reduce the size of the ranges above.
    Debug.Print Now
    varSheetA = Worksheets("Sheet1").Range(strRangeToCheck)
    varSheetB = Worksheets("Sheet2").Range(strRangeToCheck) ' or whatever your other sheet is.
    Debug.Print Now

    For iRow = LBound(varSheetA, 1) To UBound(varSheetA, 1)
        For iCol = LBound(varSheetA, 2) To UBound(varSheetA, 2)
            If varSheetA(iRow, iCol) = varSheetB(iRow, iCol) Then
                ' Cells are identical.
                ' Do nothing.
            Else
                ' Cells are different.
                ' Code goes here for whatever it is you want to do.
            End If
        Next iCol
    Next iRow

End Sub

To compare to a sheet in a different workbook, open that workbook and get the sheet as follows:

Set wbkA = Workbooks.Open(filename:="C:\MyBook.xls")
Set varSheetA = wbkA.Worksheets("Sheet1") ' or whatever sheet you need

git with development, staging and production branches

one of the best things about git is that you can change the work flow that works best for you.. I do use http://nvie.com/posts/a-successful-git-branching-model/ most of the time but you can use any workflow that fits your needs

Check if number is prime number

This is the simplest way to find prime number is

for(i=2; i<num; i++)
        {
            if(num%i == 0)
            {
                count++;
                break;
            }
        }
        if(count == 0)
        {
            Console.WriteLine("This is a Prime Number");
        }
        else
        {
            Console.WriteLine("This is not a Prime Number");
        }

Helpful Link: https://codescracker.com/java/program/java-program-check-prime.htm

Class JavaLaunchHelper is implemented in both. One of the two will be used. Which one is undefined

From what I've found online, this is a bug introduced in JDK 1.7.0_45. It appears to also be present in JDK 1.7.0_60. A bug report on Oracle's website states that, while there was a fix, it was removed before the JDK was released. I do not know why the fix was removed, but it confirms what we've already suspected -- the JDK is still broken.

The bug report claims that the error is benign and should not cause any run-time problems, though one of the comments disagrees with that. In my own experience, I have been able to work without any problems using JDK 1.7.0_60 despite seeing the message.

If this issue is causing serious problems, here are a few things I would suggest:

  • Revert back to JDK 1.7.0_25 until a fix is added to the JDK.

  • Keep an eye on the bug report so that you are aware of any work being done on this issue. Maybe even add your own comment so Oracle is aware of the severity of the issue.

  • Try the JDK early releases as they come out. One of them might fix your problem.

Instructions for installing the JDK on Mac OS X are available at JDK 7 Installation for Mac OS X. It also contains instructions for removing the JDK.

Stop setInterval call in JavaScript

setInterval() returns an interval ID, which you can pass to clearInterval():

var refreshIntervalId = setInterval(fname, 10000);

/* later */
clearInterval(refreshIntervalId);

See the docs for setInterval() and clearInterval().

Changing ViewPager to enable infinite page scrolling

Thank you for your answer Shereef.

I solved it a little bit differently.

I changed the code of the ViewPager class of the android support library. The method setCurrentItem(int)

changes the page with animation. This method calls an internal method that requires the index and a flag enabling smooth scrolling. This flag is boolean smoothScroll. Extending this method with a second parameter boolean smoothScroll solved it for me. Calling this method setCurrentItem(int index, boolean smoothScroll) allowed me to make it scroll indefinitely.

Here is a full example:

Please consider that only the center page is shown. Moreover did I store the pages seperately, allowing me to handle them with more ease.

private class Page {
  View page;
  List<..> data;
}
// page for predecessor, current, and successor
Page[] pages = new Page[3];




mDayPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

        @Override
        public void onPageSelected(int position) {
        }

        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {}

        @Override
        public void onPageScrollStateChanged(int state) {

            if (state == ViewPager.SCROLL_STATE_IDLE) {

                if (mFocusedPage == 0) {
                    // move some stuff from the 
                                            // center to the right here
                    moveStuff(pages[1], pages[2]);

                    // move stuff from the left to the center 
                    moveStuff(pages[0], pages[1]);
                    // retrieve new stuff and insert it to the left page
                    insertStuff(pages[0]);
                }
                else if (mFocusedPage == 2) {


                    // move stuff from the center to the left page
                    moveStuff(pages[1], pages[0]); 
                    // move stuff from the right to the center page
                    moveStuff(pages[2], pages[1]); 
                    // retrieve stuff and insert it to the right page
                                            insertStuff(pages[2]);
                }

                // go back to the center allowing to scroll indefinitely
                mDayPager.setCurrentItem(1, false);
            }
        }
    });

However, without Jon Willis Code I wouldn't have solved it myself.

EDIT: here is a blogpost about this:

How do I interpret precision and scale of a number in a database?

Precision, Scale, and Length in the SQL Server 2000 documentation reads:

Precision is the number of digits in a number. Scale is the number of digits to the right of the decimal point in a number. For example, the number 123.45 has a precision of 5 and a scale of 2.

How to check a radio button with jQuery?

Yes, it worked for me like a way:

$("#radio_1").attr('checked', 'checked');

Explain ExtJS 4 event handling

Firing application wide events

How to make controllers talk to each other ...

In addition to the very great answer above I want to mention application wide events which can be very useful in an MVC setup to enable communication between controllers. (extjs4.1)

Lets say we have a controller Station (Sencha MVC examples) with a select box:

Ext.define('Pandora.controller.Station', {
    extend: 'Ext.app.Controller',
    ...

    init: function() {
        this.control({
            'stationslist': {
                selectionchange: this.onStationSelect
            },
            ...
        });
    },

    ...

    onStationSelect: function(selModel, selection) {
        this.application.fireEvent('stationstart', selection[0]);
    },    
   ...
});

When the select box triggers a change event, the function onStationSelect is fired.

Within that function we see:

this.application.fireEvent('stationstart', selection[0]);

This creates and fires an application wide event that we can listen to from any other controller.

Thus in another controller we can now know when the station select box has been changed. This is done through listening to this.application.on as follows:

Ext.define('Pandora.controller.Song', {
    extend: 'Ext.app.Controller', 
    ...
    init: function() {
        this.control({
            'recentlyplayedscroller': {
                selectionchange: this.onSongSelect
            }
        });

        // Listen for an application wide event
        this.application.on({
            stationstart: this.onStationStart, 
                scope: this
        });
    },
    ....
    onStationStart: function(station) {
        console.info('I called to inform you that the Station controller select box just has been changed');
        console.info('Now what do you want to do next?');
    },
}

If the selectbox has been changed we now fire the function onStationStart in the controller Song also ...

From the Sencha docs:

Application events are extremely useful for events that have many controllers. Instead of listening for the same view event in each of these controllers, only one controller listens for the view event and fires an application-wide event that the others can listen for. This also allows controllers to communicate with one another without knowing about or depending on each other’s existence.

In my case: Clicking on a tree node to update data in a grid panel.

Update 2016 thanks to @gm2008 from the comments below:

In terms of firing application-wide custom events, there is a new method now after ExtJS V5.1 is published, which is using Ext.GlobalEvents.

When you fire events, you can call: Ext.GlobalEvents.fireEvent('custom_event');

When you register a handler of the event, you call: Ext.GlobalEvents.on('custom_event', function(arguments){/* handler codes*/}, scope);

This method is not limited to controllers. Any component can handle a custom event through putting the component object as the input parameter scope.

Found in Sencha Docs: MVC Part 2

Get last key-value pair in PHP array

If you have an array

$last_element = array_pop(array);

How to create unique keys for React elements?

Do not use this return `${ pre }_${ new Date().getTime()}`;. It's better to have the array index instead of that because, even though it's not ideal, that way you will at least get some consistency among the list components, with the new Date function you will get constant inconsistency. That means every new iteration of the function will lead to a new truly unique key.

The unique key doesn't mean that it needs to be globally unique, it means that it needs to be unique in the context of the component, so it doesn't run useless re-renders all the time. You won't feel the problem associated with new Date initially, but you will feel it, for example, if you need to get back to the already rendered list and React starts getting all confused because it doesn't know which component changed and which didn't, resulting in memory leaks, because, you guessed it, according to your Date key, every component changed.

Now to my answer. Let's say you are rendering a list of YouTube videos. Use the video id (arqTu9Ay4Ig) as a unique ID. That way, if that ID doesn't change, the component will stay the same, but if it does, React will recognize that it's a new Video and change it accordingly.

It doesn't have to be that strict, the little more relaxed variant is to use the title, like Erez Hochman already pointed out, or a combination of the attributes of the component (title plus category), so you can tell React to check if they have changed or not.

edited some unimportant stuff

Convert DataTable to CSV stream

You can try using something like this. In this case I used one stored procedure to get more data tables and export all of them using CSV.

using System;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.IO;

namespace bo
{
class Program
{
    static private void CreateCSVFile(DataTable dt, string strFilePath)
    {
        #region Export Grid to CSV
        // Create the CSV file to which grid data will be exported.
        StreamWriter sw = new StreamWriter(strFilePath, false);
        int iColCount = dt.Columns.Count;

        // First we will write the headers.

        //DataTable dt = m_dsProducts.Tables[0];
        for (int i = 0; i < iColCount; i++)
        {
            sw.Write(dt.Columns[i]);
            if (i < iColCount - 1)
            {
                sw.Write(";");
            }
        }
        sw.Write(sw.NewLine);

        // Now write all the rows.
        foreach (DataRow dr in dt.Rows)
        {
            for (int i = 0; i < iColCount; i++)
            {
                if (!Convert.IsDBNull(dr[i]))
                {
                    sw.Write(dr[i].ToString());
                }
                if (i < iColCount -1 )
                {
                    sw.Write(";");
                }
            }
            sw.Write(sw.NewLine);
        }
        sw.Close();

        #endregion
    }
    static void Main(string[] args)
    {
        string strConn = "connection string to sql";
        string direktorij = @"d:";
        SqlConnection conn = new SqlConnection(strConn); 
        SqlCommand command = new SqlCommand("sp_ado_pos_data", conn);
        command.CommandType = CommandType.StoredProcedure;
        command.Parameters.Add('@skl_id', SqlDbType.Int).Value = 158;
        SqlDataAdapter adapter = new SqlDataAdapter(command);
        DataSet ds = new DataSet();
        adapter.Fill(ds);
        for (int i = 0; i < ds.Tables.Count; i++)
        {
            string datoteka  = (string.Format(@"{0}tablea{1}.csv", direktorij, i));
            DataTable tabela = ds.Tables[i];
            CreateCSVFile(tabela,datoteka );
            Console.WriteLine("Generišem tabelu {0}", datoteka);
        }
        Console.ReadKey();
    }
  }
}

Laravel, sync() - how to sync an array and also pass additional pivot fields?

In order to sync multiple models along with custom pivot data, you need this:

$user->roles()->sync([ 
    1 => ['expires' => true],
    2 => ['expires' => false],
    ...
]);

Ie.

sync([
    related_id => ['pivot_field' => value],
    ...
]);

edit

Answering the comment:

$speakers  = (array) Input::get('speakers'); // related ids
$pivotData = array_fill(0, count($speakers), ['is_speaker' => true]);
$syncData  = array_combine($speakers, $pivotData);

$user->roles()->sync($syncData);

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

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

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

See Labelling documentation for more details.

How can I write text on a HTML5 canvas element?

Yes of course you can write a text on canvas with ease, and you can set the font name, font size and font color. There are two method to build a text on Canvas, i.e. fillText() and strokeText(). fillText() method is used to make a text that can only be filled with color, whereas strokeText() is used to make a text that can only be given an outline color. So if we want to build a text that filled with color and have outline color, we must use both of them.

here the full example, how to write text on canvas :

<canvas id="Canvas01" width="400" height="200" style="border:2px solid #bbb; margin-left:10px; margin-top:10px;"></canvas>

<script>
  var canvas = document.getElementById('Canvas01');
  var ctx = canvas.getContext('2d');

  ctx.fillStyle= "red";
  ctx.font = "italic bold 35pt Tahoma";
  //syntax : .fillText("text", x, y)
  ctx.fillText("StacOverFlow",30,80);

</script>

Here the demo for this, and you can try your self for any modification: http://okeschool.com/examples/canvas/html5-canvas-text-color

Command to close an application of console?

You can Try This

Application.Exit();

javascript object max size limit

Step 1 is always to first determine where the problem lies. Your title and most of your question seem to suggest that you're running into quite a low length limit on the length of a string in JavaScript / on browsers, an improbably low limit. You're not. Consider:

var str;

document.getElementById('theButton').onclick = function() {
  var build, counter;

  if (!str) {
    str = "0123456789";
    build = [];
    for (counter = 0; counter < 900; ++counter) {
      build.push(str);
    }
    str = build.join("");
  }
  else {
    str += str;
  }
  display("str.length = " + str.length);
};

Live copy

Repeatedly clicking the relevant button keeps making the string longer. With Chrome, Firefox, Opera, Safari, and IE, I've had no trouble with strings more than a million characters long:

str.length = 9000
str.length = 18000
str.length = 36000
str.length = 72000
str.length = 144000
str.length = 288000
str.length = 576000
str.length = 1152000
str.length = 2304000
str.length = 4608000
str.length = 9216000
str.length = 18432000

...and I'm quite sure I could got a lot higher than that.

So it's nothing to do with a length limit in JavaScript. You haven't show your code for sending the data to the server, but most likely you're using GET which means you're running into the length limit of a GET request, because GET parameters are put in the query string. Details here.

You need to switch to using POST instead. In a POST request, the data is in the body of the request rather than in the URL, and can be very, very large indeed.

MVC4 StyleBundle not resolving images

After little investigation I concluded the followings: You have 2 options:

  1. go with transformations. Very usefull package for this: https://bundletransformer.codeplex.com/ you need following transformation for every problematic bundle:

    BundleResolver.Current = new CustomBundleResolver();
    var cssTransformer = new StyleTransformer();
    standardCssBundle.Transforms.Add(cssTransformer);
    bundles.Add(standardCssBundle);
    

Advantages: of this solution, you can name your bundle whatever you want => you can combine css files into one bundle from different directories. Disadvantages: You need to transform every problematic bundle

  1. Use the same relative root for the name of the bundle like where the css file is located. Advantages: there is no need for transformation. Disadvantages: You have limitation on combining css sheets from different directories into one bundle.

What is <=> (the 'Spaceship' Operator) in PHP 7?

Its a new operator for combined comparison. Similar to strcmp() or version_compare() in behavior, but it can be used on all generic PHP values with the same semantics as <, <=, ==, >=, >. It returns 0 if both operands are equal, 1 if the left is greater, and -1 if the right is greater. It uses exactly the same comparison rules as used by our existing comparison operators: <, <=, ==, >= and >.

click here to know more

Why do we assign a parent reference to the child object in Java?

I think all explanations above are a bit too technical for the people who are new to Object Oriented Programming (OOP). Years ago, it took me a while to wrap my head around this (as Jr Java Developer) and I really did no understand why we use a parent class or an interface to hide the actual class we are actually calling under the covers.

  1. The immediate reason why is to hide complexity, so that the caller does not need to change often (be hacked and jacked in laymen's terms). This makes a lot of sense, especially if you goals is to avoid creating bugs. And the more you modify code, the more likely it is that you will have some of them creep up on you. On the other hand, if you just extend code, it is way less likely that you will have bugs because you concentrate on one thing at a time and your old code does not change or changes just a bit. Imagine that you have simple application that allows the employees in the medical profession to create profiles. For simplicity, let's assume that we have only GeneralPractitioners, Surgeons, and Nurses (in reality there are many more specific professions, of course). For each profession, you want to store some general information and some specific to that professional alone. For example, a Surgeon may have general fields like firstName, lastName, yearsOfExperience as general fields but also specific fields, e.g. specializations stored in an list instance variable, like List with contents simiar to "Bone Surgery", "Eye Surgery", etc. A Nurse would not have any of that but may have list procedures they are familiar with, GeneralPractioners would have their own specifics. As a result, how you save a profile of a specifics. However, you don't want your ProfileManager class to know about these differences, as they will inevitably change and increase over time as your application expands its functionality to cover more medical professions, e.g. Physio Therapist, Cardiologist, Oncologist, etc. All you want your ProfileManger to do is just say save(), no matter whose profile it is saving. Thus, it is common practice to hide this behind and Interface, and Abstract Class, or a Parent Class (if you plan to allow creating a general medical employee). In this case, let's choose a Parent class and call it MedicalEmployee. Under the covers, it can reference any of the above specific classes that extend it. When the ProfileManager calls myMedicalEmployee.save() the save() method will be polymorphically (many-structurally) be resolved to the correct class type that was used to create the profile originally, for example Nurse and call the save() method in that class.

  2. In many cases, you don't really know what implementation you will need at runtime. From the example above, you have no idea if a GeneralPractitioner, a Surgeon, or a Nurse would create a profile. Yet, you know that you need to save that profile once completed, no matter what. MedicalEmployee.profile() does exactly that. It is replicated (overridden) by each specific type of MedicalEmployee - GeneralPractitioner, Surgeon, Nurse,

  3. The result of (1) and (2) above is that you now can add new medical professions, implement save() in each new class, thereby overriding the save() method in MedicalEmployee, and you don't have to modify ProfileManager at all.

MySQL - Cannot add or update a child row: a foreign key constraint fails

I solved my 'foreign key constraint fails' issues by adding the following code to the start of the SQL code (this was for importing values to a table)

SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT;
SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS;
SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION;
SET NAMES utf8;
SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0;
SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0;
SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO';
SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0; 

Then adding this code to the end of the file

SET SQL_MODE=@OLD_SQL_MODE;
SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS;
SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS;
SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT;
SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS;
SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION;
SET SQL_NOTES=@OLD_SQL_NOTES; 

Web scraping with Python

I use a combination of Scrapemark (finding urls - py2) and httlib2 (downloading images - py2+3). The scrapemark.py has 500 lines of code, but uses regular expressions, so it may be not so fast, did not test.

Example for scraping your website:

import sys
from pprint import pprint
from scrapemark import scrape

pprint(scrape("""
    <table class="spad">
        <tbody>
            {*
                <tr>
                    <td>{{[].day}}</td>
                    <td>{{[].sunrise}}</td>
                    <td>{{[].sunset}}</td>
                    {# ... #}
                </tr>
            *}
        </tbody>
    </table>
""", url=sys.argv[1] ))

Usage:

python2 sunscraper.py http://www.example.com/

Result:

[{'day': u'1. Dez 2012', 'sunrise': u'08:18', 'sunset': u'16:10'},
 {'day': u'2. Dez 2012', 'sunrise': u'08:19', 'sunset': u'16:10'},
 {'day': u'3. Dez 2012', 'sunrise': u'08:21', 'sunset': u'16:09'},
 {'day': u'4. Dez 2012', 'sunrise': u'08:22', 'sunset': u'16:09'},
 {'day': u'5. Dez 2012', 'sunrise': u'08:23', 'sunset': u'16:08'},
 {'day': u'6. Dez 2012', 'sunrise': u'08:25', 'sunset': u'16:08'},
 {'day': u'7. Dez 2012', 'sunrise': u'08:26', 'sunset': u'16:07'}]

Combine two or more columns in a dataframe into a new column with a new name

As already mentioned in comments by Uwe and UseR, a general solution in the tidyverse format would be to use the command unite:

library(tidyverse)

n = c(2, 3, 5) 
s = c("aa", "bb", "cc") 
b = c(TRUE, FALSE, TRUE) 

df = data.frame(n, s, b) %>% 
  unite(x, c(n, s), sep = " ", remove = FALSE)

What is the "Illegal Instruction: 4" error and why does "-mmacosx-version-min=10.x" fix it?

I'm consciously writing this answer to an old question with this in mind, because the other answers didn't help me.

I got the Illegal Instruction: 4 while running the binary on the same system I had compiled it on, so -mmacosx-version-min didn't help.

I was using gcc in Code Blocks 16 on Mac OS X 10.11.

However, turning off all of Code Blocks' compiler flags for optimization worked. So look at all the flags Code Blocks set (right-click on the Project -> "Build Properties") and turn off all the flags you are sure you don't need, especially -s and the -Oflags for optimization. That did it for me.

Expression must have class type

It's a pointer, so instead try:

a->f();

Basically the operator . (used to access an object's fields and methods) is used on objects and references, so:

A a;
a.f();
A& ref = a;
ref.f();

If you have a pointer type, you have to dereference it first to obtain a reference:

A* ptr = new A();
(*ptr).f();
ptr->f();

The a->b notation is usually just a shorthand for (*a).b.

A note on smart pointers

The operator-> can be overloaded, which is notably used by smart pointers. When you're using smart pointers, then you also use -> to refer to the pointed object:

auto ptr = make_unique<A>();
ptr->f();

Solve error javax.mail.AuthenticationFailedException

May be this problem cause by Gmail account protection. Just click below link and disable security settings.It will work. https://www.google.com/settings/security/lesssecureapps

React setState not updating state

The setstate is asynchronous in react, so to see the updated state in console use the callback as shown below (Callback function will execute after the setstate update)

enter image description here

The below method is "not recommended" but for understanding, if you mutate state directly you can see the updated state in the next line. I repeat this is "not recommended"

enter image description here

How can I execute a python script from an html button?

Best way is to Use a Python Web Frame Work you can choose Django/Flask. I will suggest you to Use Django because it's more powerful. Here is Step by guide to get complete your task :

pip install django
django-admin createproject buttonpython

then you have to create a file name views.py in buttonpython directory.

write below code in views.py:

from django.http import HttpResponse

def sample(request):
    #your python script code
    output=code output
    return HttpResponse(output)

Once done navigate to urls.py and add this stanza

from . import views

path('', include('blog.urls')),

Now go to parent directory and execute manage.py

python manage.py runserver 127.0.0.1:8001

Step by Step Guide in Detail: Run Python script on clicking HTML button

How to set the size of a column in a Bootstrap responsive table

Bootstrap 4.0

Be aware of all migration changes from Bootstrap 3 to 4. On the table you now need to enable flex box by adding the class d-flex, and drop the xs to allow bootstrap to automatically detect the viewport.

<div class="container-fluid">
    <table id="productSizes" class="table">
        <thead>
            <tr class="d-flex">
                <th class="col-1">Size</th>
                <th class="col-3">Bust</th>
                <th class="col-3">Waist</th>
                <th class="col-5">Hips</th>
            </tr>
        </thead>
        <tbody>
            <tr class="d-flex">
                <td class="col-1">6</td>
                <td class="col-3">79 - 81</td>
                <td class="col-3">61 - 63</td>
                <td class="col-5">89 - 91</td>
            </tr>
            <tr class="d-flex">
                <td class="col-1">8</td>
                <td class="col-3">84 - 86</td>
                <td class="col-3">66 - 68</td>
                <td class="col-5">94 - 96</td>
            </tr>
        </tbody>
    </table>

bootply

Bootstrap 3.2

Table column width use the same layout as grids do; using col-[viewport]-[size]. Remember the column sizes should total 12; 1 + 3 + 3 + 5 = 12 in this example.

        <thead>
            <tr>
                <th class="col-xs-1">Size</th>
                <th class="col-xs-3">Bust</th>
                <th class="col-xs-3">Waist</th>
                <th class="col-xs-5">Hips</th>
            </tr>
        </thead>

Remember to set the <th> elements rather than the <td> elements so it sets the whole column. Here is a working BOOTPLY.

Thanks to @Dan for reminding me to always work mobile view (col-xs-*) first.

Batch file to move files to another directory

Try:

move "C:\files\*.txt" "C:\txt"

How to create a JavaScript callback for knowing when an image is loaded?

.complete + callback

This is a standards compliant method without extra dependencies, and waits no longer than necessary:

var img = document.querySelector('img')

function loaded() {
  alert('loaded')
}

if (img.complete) {
  loaded()
} else {
  img.addEventListener('load', loaded)
  img.addEventListener('error', function() {
      alert('error')
  })
}

Source: http://www.html5rocks.com/en/tutorials/es6/promises/

How do I check the difference, in seconds, between two dates?

if you want to compute differences between two known dates, use total_seconds like this:

import datetime as dt

a = dt.datetime(2013,12,30,23,59,59)
b = dt.datetime(2013,12,31,23,59,59)

(b-a).total_seconds()

86400.0

#note that seconds doesn't give you what you want:
(b-a).seconds

0

Why use $_SERVER['PHP_SELF'] instead of ""

There is no difference. The $_SERVER['PHP_SELF'] just makes the execution time slower by like 0.000001 second.

What are public, private and protected in object oriented programming?

They are access modifiers and help us implement Encapsulation (or information hiding). They tell the compiler which other classes should have access to the field or method being defined.

private - Only the current class will have access to the field or method.

protected - Only the current class and subclasses (and sometimes also same-package classes) of this class will have access to the field or method.

public - Any class can refer to the field or call the method.

This assumes these keywords are used as part of a field or method declaration within a class definition.

Select columns in PySpark dataframe

Use df.schema.names:

spark.version
# u'2.2.0'

df = spark.createDataFrame([("foo", 1), ("bar", 2)])
df.show()
# +---+---+ 
# | _1| _2|
# +---+---+
# |foo|  1| 
# |bar|  2|
# +---+---+

df.schema.names
# ['_1', '_2']

for i in df.schema.names:
  # df_new = df.withColumn(i, [do-something])
  print i
# _1
# _2

Add a Progress Bar in WebView

pass your url in this method

private void startWebView(String url) {

        WebSettings settings = webView.getSettings();

        settings.setJavaScriptEnabled(true);
        webView.setScrollBarStyle(View.SCROLLBARS_OUTSIDE_OVERLAY);

        webView.getSettings().setBuiltInZoomControls(true);
        webView.getSettings().setUseWideViewPort(true);
        webView.getSettings().setLoadWithOverviewMode(true);

        progressDialog = new ProgressDialog(ContestActivity.this);
        progressDialog.setMessage("Loading...");
        progressDialog.show();

        webView.setWebViewClient(new WebViewClient() {
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                view.loadUrl(url);
                return true;
            }

            @Override
            public void onPageFinished(WebView view, String url) {
                if (progressDialog.isShowing()) {
                    progressDialog.dismiss();
                }
            }

            @Override
            public void onReceivedError(WebView view, int errorCode, String description, String failingUrl) {
                Toast.makeText(ContestActivity.this, "Error:" + description, Toast.LENGTH_SHORT).show();

            }
        });
        webView.loadUrl(url);
    }

Correct way to import lodash

If you are using babel, you should check out babel-plugin-lodash, it will cherry-pick the parts of lodash you are using for you, less hassle and a smaller bundle.

It has a few limitations:

  • You must use ES2015 imports to load Lodash
  • Babel < 6 & Node.js < 4 aren’t supported
  • Chain sequences aren’t supported. See this blog post for alternatives.
  • Modularized method packages aren’t supported

Getting the location from an IP address

The following is a modified version of a snippet I found that uses http://ipinfodb.com/ip_locator.php to get its information. Keep in mind, you can also apply for an API key with them and use the API directly to get the information supplied as you see fit.

Snippet

function detect_location($ip=NULL, $asArray=FALSE) {
    if (empty($ip)) {
        if (!empty($_SERVER['HTTP_CLIENT_IP'])) { $ip = $_SERVER['HTTP_CLIENT_IP']; }
        elseif (!empty($_SERVER['HTTP_X_FORWARDED_FOR'])) { $ip = $_SERVER['HTTP_X_FORWARDED_FOR']; }
        else { $ip = $_SERVER['REMOTE_ADDR']; }
    }
    elseif (!is_string($ip) || strlen($ip) < 1 || $ip == '127.0.0.1' || $ip == 'localhost') {
        $ip = '8.8.8.8';
    }

    $url = 'http://ipinfodb.com/ip_locator.php?ip=' . urlencode($ip);
    $i = 0; $content; $curl_info;

    while (empty($content) && $i < 5) {
        $ch = curl_init();
        $curl_opt = array(
            CURLOPT_FOLLOWLOCATION => 1,
            CURLOPT_HEADER => 0,
            CURLOPT_RETURNTRANSFER  => 1,
            CURLOPT_URL => $url,
            CURLOPT_TIMEOUT => 1,
            CURLOPT_REFERER => 'http://' . $_SERVER['HTTP_HOST'],
        );
        if (isset($_SERVER['HTTP_USER_AGENT'])) $curl_opt[CURLOPT_USERAGENT] = $_SERVER['HTTP_USER_AGENT'];
        curl_setopt_array($ch, $curl_opt);
        $content = curl_exec($ch);
        if (!is_null($curl_info)) $curl_info = curl_getinfo($ch);
        curl_close($ch);
    }

    $araResp = array();
    if (preg_match('{<li>City : ([^<]*)</li>}i', $content, $regs)) $araResp['city'] = trim($regs[1]);
    if (preg_match('{<li>State/Province : ([^<]*)</li>}i', $content, $regs)) $araResp['state'] = trim($regs[1]);
    if (preg_match('{<li>Country : ([^<]*)}i', $content, $regs)) $araResp['country'] = trim($regs[1]);
    if (preg_match('{<li>Zip or postal code : ([^<]*)</li>}i', $content, $regs)) $araResp['zip'] = trim($regs[1]);
    if (preg_match('{<li>Latitude : ([^<]*)</li>}i', $content, $regs)) $araResp['latitude'] = trim($regs[1]);
    if (preg_match('{<li>Longitude : ([^<]*)</li>}i', $content, $regs)) $araResp['longitude'] = trim($regs[1]);
    if (preg_match('{<li>Timezone : ([^<]*)</li>}i', $content, $regs)) $araResp['timezone'] = trim($regs[1]);
    if (preg_match('{<li>Hostname : ([^<]*)</li>}i', $content, $regs)) $araResp['hostname'] = trim($regs[1]);

    $strResp = ($araResp['city'] != '' && $araResp['state'] != '') ? ($araResp['city'] . ', ' . $araResp['state']) : 'UNKNOWN';

    return $asArray ? $araResp : $strResp;
}

To Use

detect_location();
//  returns "CITY, STATE" based on user IP

detect_location('xxx.xxx.xxx.xxx');
//  returns "CITY, STATE" based on IP you provide

detect_location(NULL, TRUE);    //   based on user IP
//  returns array(8) { ["city"] => "CITY", ["state"] => "STATE", ["country"] => "US", ["zip"] => "xxxxx", ["latitude"] => "xx.xxxxxx", ["longitude"] => "-xx.xxxxxx", ["timezone"] => "-07:00", ["hostname"] => "xx-xx-xx-xx.host.name.net" }

detect_location('xxx.xxx.xxx.xxx', TRUE);   //   based on IP you provide
//  returns array(8) { ["city"] => "CITY", ["state"] => "STATE", ["country"] => "US", ["zip"] => "xxxxx", ["latitude"] => "xx.xxxxxx", ["longitude"] => "-xx.xxxxxx", ["timezone"] => "-07:00", ["hostname"] => "xx-xx-xx-xx.host.name.net" }

How best to read a File into List<string>

string inLine = reader.ReadToEnd();
myList = inLine.Split(new string[] { "\r\n" }, StringSplitOptions.None).ToList();

This answer misses the original point, which was that they were getting an OutOfMemory error. If you proceed with the above version, you are sure to hit it if your system does not have the appropriate CONTIGUOUS available ram to load the file.

You simply must break it into parts, and either store as List or String[] either way.

This view is not constrained vertically. At runtime it will jump to the left unless you add a vertical constraint

Just copy this code to all components that you will drag.

app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"

example:

<TextView
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    android:text="To:"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    tools:layout_editor_absoluteX="7dp"
    tools:layout_editor_absoluteY="4dp"
    android:id="@+id/textTo"/>

What is %0|%0 and how does it work?

This is known as a fork bomb. It keeps splitting itself until there is no option but to restart the system. http://en.wikipedia.org/wiki/Fork_bomb

Implement Validation for WPF TextBoxes

When it comes to Muhammad Mehdi's answer, it is better to do:

private void salary_texbox_PreviewTextInput(object sender, TextCompositionEventArgs e)
{
     Regex regex = new Regex ( "[^0-9]+" );
     if(regex.IsMatch(e.Text))
     {
         MessageBox.Show("Error");
     }
}

Because when comparing with the TextCompositionEventArgs it gets also the last character, while with the textbox.Text it does not. With textbox, the error will show after next inserted character.

Why this "Implicit declaration of function 'X'"?

summation and your other functions are defined after they're used in main, and so the compiler has made a guess about it's signature; in other words, an implicit declaration has been assumed.

You should declare the function before it's used and get rid of the warning. In the C99 specification, this is an error.

Either move the function bodies before main, or include method signatures before main, e.g.:

#include <stdio.h>

int summation(int *, int *, int *);

int main()
{
    // ...

JavaScript data grid for millions of rows

Disclaimer: i heavily use YUI DataTable without no headache for a long time. It is powerful and stable. For your needs, you can use a ScrollingDataTable wich suports

  • x-scrolling
  • y-scrolling
  • xy-scrolling
  • A powerful Event mechanism

For what you need, i think you want is a tableScrollEvent. Its API says

Fired when a fixed scrolling DataTable has a scroll.

As each DataTable uses a DataSource, you can monitoring its data through tableScrollEvent along with render loop size in order to populate your ScrollingDataTable according to your needs.

Render loop size says

In cases where your DataTable needs to display the entirety of a very large set of data, the renderLoopSize config can help manage browser DOM rendering so that the UI thread does not get locked up on very large tables. Any value greater than 0 will cause the DOM rendering to be executed in setTimeout() chains that render the specified number of rows in each loop. The ideal value should be determined per implementation since there are no hard and fast rules, only general guidelines:

  • By default renderLoopSize is 0, so all rows are rendered in a single loop. A renderLoopSize > 0 adds overhead so use thoughtfully.
  • If your set of data is large enough (number of rows X number of Columns X formatting complexity) that users experience latency in the visual rendering and/or it causes the script to hang, consider setting a renderLoopSize.
  • A renderLoopSize under 50 probably isn't worth it. A renderLoopSize > 100 is probably better.
  • A data set is probably not considered large enough unless it has hundreds and hundreds of rows.
  • Having a renderLoopSize > 0 and < total rows does cause the table to be rendered in one loop (same as renderLoopSize = 0) but it also triggers functionality such as post-render row striping to be handled from a separate setTimeout thread.

For instance

// Render 100 rows per loop
 var dt = new YAHOO.widget.DataTable(<WHICH_DIV_WILL_STORE_YOUR_DATATABLE>, <HOW YOUR_TABLE_IS STRUCTURED>, <WHERE_DOES_THE_DATA_COME_FROM>, {
     renderLoopSize:100
 });

<WHERE_DOES_THE_DATA_COME_FROM> is just a single DataSource. It can be a JSON, JSFunction, XML and even a single HTML element

Here you can see a Simple tutorial, provided by me. Be aware no other DATA_TABLE pluglin supports single and dual click at the same time. YUI DataTable allows you. And more, you can use it even with JQuery without no headache

Some examples, you can see

Feel free to question about anything else you want about YUI DataTable.

regards,

Make error: missing separator

For me, the problem was that I had some end-of-line # ... comments embedded within a define ... endef multi-line variable definition. Removing the comments made the problem go away.

How can I change UIButton title color?

Solution in Swift 3:

button.setTitleColor(UIColor.red, for: .normal)

This will set the title color of button.

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

Let's get one thing out of the way first. The explanation that yield from g is equivalent to for v in g: yield v does not even begin to do justice to what yield from is all about. Because, let's face it, if all yield from does is expand the for loop, then it does not warrant adding yield from to the language and preclude a whole bunch of new features from being implemented in Python 2.x.

What yield from does is it establishes a transparent bidirectional connection between the caller and the sub-generator:

  • The connection is "transparent" in the sense that it will propagate everything correctly too, not just the elements being generated (e.g. exceptions are propagated).

  • The connection is "bidirectional" in the sense that data can be both sent from and to a generator.

(If we were talking about TCP, yield from g might mean "now temporarily disconnect my client's socket and reconnect it to this other server socket".)

BTW, if you are not sure what sending data to a generator even means, you need to drop everything and read about coroutines first—they're very useful (contrast them with subroutines), but unfortunately lesser-known in Python. Dave Beazley's Curious Course on Coroutines is an excellent start. Read slides 24-33 for a quick primer.

Reading data from a generator using yield from

def reader():
    """A generator that fakes a read from a file, socket, etc."""
    for i in range(4):
        yield '<< %s' % i

def reader_wrapper(g):
    # Manually iterate over data produced by reader
    for v in g:
        yield v

wrap = reader_wrapper(reader())
for i in wrap:
    print(i)

# Result
<< 0
<< 1
<< 2
<< 3

Instead of manually iterating over reader(), we can just yield from it.

def reader_wrapper(g):
    yield from g

That works, and we eliminated one line of code. And probably the intent is a little bit clearer (or not). But nothing life changing.

Sending data to a generator (coroutine) using yield from - Part 1

Now let's do something more interesting. Let's create a coroutine called writer that accepts data sent to it and writes to a socket, fd, etc.

def writer():
    """A coroutine that writes data *sent* to it to fd, socket, etc."""
    while True:
        w = (yield)
        print('>> ', w)

Now the question is, how should the wrapper function handle sending data to the writer, so that any data that is sent to the wrapper is transparently sent to the writer()?

def writer_wrapper(coro):
    # TBD
    pass

w = writer()
wrap = writer_wrapper(w)
wrap.send(None)  # "prime" the coroutine
for i in range(4):
    wrap.send(i)

# Expected result
>>  0
>>  1
>>  2
>>  3

The wrapper needs to accept the data that is sent to it (obviously) and should also handle the StopIteration when the for loop is exhausted. Evidently just doing for x in coro: yield x won't do. Here is a version that works.

def writer_wrapper(coro):
    coro.send(None)  # prime the coro
    while True:
        try:
            x = (yield)  # Capture the value that's sent
            coro.send(x)  # and pass it to the writer
        except StopIteration:
            pass

Or, we could do this.

def writer_wrapper(coro):
    yield from coro

That saves 6 lines of code, make it much much more readable and it just works. Magic!

Sending data to a generator yield from - Part 2 - Exception handling

Let's make it more complicated. What if our writer needs to handle exceptions? Let's say the writer handles a SpamException and it prints *** if it encounters one.

class SpamException(Exception):
    pass

def writer():
    while True:
        try:
            w = (yield)
        except SpamException:
            print('***')
        else:
            print('>> ', w)

What if we don't change writer_wrapper? Does it work? Let's try

# writer_wrapper same as above

w = writer()
wrap = writer_wrapper(w)
wrap.send(None)  # "prime" the coroutine
for i in [0, 1, 2, 'spam', 4]:
    if i == 'spam':
        wrap.throw(SpamException)
    else:
        wrap.send(i)

# Expected Result
>>  0
>>  1
>>  2
***
>>  4

# Actual Result
>>  0
>>  1
>>  2
Traceback (most recent call last):
  ... redacted ...
  File ... in writer_wrapper
    x = (yield)
__main__.SpamException

Um, it's not working because x = (yield) just raises the exception and everything comes to a crashing halt. Let's make it work, but manually handling exceptions and sending them or throwing them into the sub-generator (writer)

def writer_wrapper(coro):
    """Works. Manually catches exceptions and throws them"""
    coro.send(None)  # prime the coro
    while True:
        try:
            try:
                x = (yield)
            except Exception as e:   # This catches the SpamException
                coro.throw(e)
            else:
                coro.send(x)
        except StopIteration:
            pass

This works.

# Result
>>  0
>>  1
>>  2
***
>>  4

But so does this!

def writer_wrapper(coro):
    yield from coro

The yield from transparently handles sending the values or throwing values into the sub-generator.

This still does not cover all the corner cases though. What happens if the outer generator is closed? What about the case when the sub-generator returns a value (yes, in Python 3.3+, generators can return values), how should the return value be propagated? That yield from transparently handles all the corner cases is really impressive. yield from just magically works and handles all those cases.

I personally feel yield from is a poor keyword choice because it does not make the two-way nature apparent. There were other keywords proposed (like delegate but were rejected because adding a new keyword to the language is much more difficult than combining existing ones.

In summary, it's best to think of yield from as a transparent two way channel between the caller and the sub-generator.

References:

  1. PEP 380 - Syntax for delegating to a sub-generator (Ewing) [v3.3, 2009-02-13]
  2. PEP 342 - Coroutines via Enhanced Generators (GvR, Eby) [v2.5, 2005-05-10]

Big O, how do you calculate/approximate it?

In addition to using the master method (or one of its specializations), I test my algorithms experimentally. This can't prove that any particular complexity class is achieved, but it can provide reassurance that the mathematical analysis is appropriate. To help with this reassurance, I use code coverage tools in conjunction with my experiments, to ensure that I'm exercising all the cases.

As a very simple example say you wanted to do a sanity check on the speed of the .NET framework's list sort. You could write something like the following, then analyze the results in Excel to make sure they did not exceed an n*log(n) curve.

In this example I measure the number of comparisons, but it's also prudent to examine the actual time required for each sample size. However then you must be even more careful that you are just measuring the algorithm and not including artifacts from your test infrastructure.

int nCmp = 0;
System.Random rnd = new System.Random();

// measure the time required to sort a list of n integers
void DoTest(int n)
{
   List<int> lst = new List<int>(n);
   for( int i=0; i<n; i++ )
      lst[i] = rnd.Next(0,1000);

   // as we sort, keep track of the number of comparisons performed!
   nCmp = 0;
   lst.Sort( delegate( int a, int b ) { nCmp++; return (a<b)?-1:((a>b)?1:0)); }

   System.Console.Writeline( "{0},{1}", n, nCmp );
}


// Perform measurement for a variety of sample sizes.
// It would be prudent to check multiple random samples of each size, but this is OK for a quick sanity check
for( int n = 0; n<1000; n++ )
   DoTest(n);

Currency formatting in Python

See the locale module.

This does currency (and date) formatting.

>>> import locale
>>> locale.setlocale( locale.LC_ALL, '' )
'English_United States.1252'
>>> locale.currency( 188518982.18 )
'$188518982.18'
>>> locale.currency( 188518982.18, grouping=True )
'$188,518,982.18'

Working with $scope.$emit and $scope.$on

You can call a service from your controller that returns a promise and then use it in your controller. And further use $emit or $broadcast to inform other controllers about it. In my case, I had to make http calls through my service, so I did something like this :

function ParentController($scope, testService) {
    testService.getList()
        .then(function(data) {
            $scope.list = testService.list;
        })
        .finally(function() {
            $scope.$emit('listFetched');
        })


    function ChildController($scope, testService) {
        $scope.$on('listFetched', function(event, data) {
            // use the data accordingly
        })
    }

and my service looks like this

    app.service('testService', ['$http', function($http) {

        this.list = [];

        this.getList = function() {
            return $http.get(someUrl)
                .then(function(response) {
                    if (typeof response.data === 'object') {
                        list = response.data.results;

                        return response.data;
                    } else {
                        // invalid response
                        return $q.reject(response.data);
                    }

                }, function(response) {
                    // something went wrong
                    return $q.reject(response.data);
                });

        }

    }])

How to make a ssh connection with python?

Notice that this doesn't work in Windows.
The module pxssh does exactly what you want:
For example, to run 'ls -l' and to print the output, you need to do something like that :

from pexpect import pxssh
s = pxssh.pxssh()
if not s.login ('localhost', 'myusername', 'mypassword'):
    print "SSH session failed on login."
    print str(s)
else:
    print "SSH session login successful"
    s.sendline ('ls -l')
    s.prompt()         # match the prompt
    print s.before     # print everything before the prompt.
    s.logout()

Some links :
Pxssh docs : http://dsnra.jpl.nasa.gov/software/Python/site-packages/Contrib/pxssh.html
Pexpect (pxssh is based on pexpect) : http://pexpect.readthedocs.io/en/stable/

How to write data to a JSON file using Javascript

You have to be clear on what you mean by "JSON".

Some people use the term JSON incorrectly to refer to a plain old JavaScript object, such as [{a: 1}]. This one happens to be an array. If you want to add a new element to the array, just push it, as in

var arr = [{a: 1}];
arr.push({b: 2});

< [{a: 1}, {b: 2}]

The word JSON may also be used to refer to a string which is encoded in JSON format:

var json = '[{"a": 1}]';

Note the (single) quotation marks indicating that this is a string. If you have such a string that you obtained from somewhere, you need to first parse it into a JavaScript object, using JSON.parse:

var obj = JSON.parse(json);

Now you can manipulate the object any way you want, including push as shown above. If you then want to put it back into a JSON string, then you use JSON.stringify:

var new_json = JSON.stringify(obj.push({b: 2}));
'[{"a": 1}, {"b": 1}]'

JSON is also used as a common way to format data for transmission of data to and from a server, where it can be saved (persisted). This is where ajax comes in. Ajax is used both to obtain data, often in JSON format, from a server, and/or to send data in JSON format up to to the server. If you received a response from an ajax request which is JSON format, you may need to JSON.parse it as described above. Then you can manipulate the object, put it back into JSON format with JSON.stringify, and use another ajax call to send the data to the server for storage or other manipulation.

You use the term "JSON file". Normally, the word "file" is used to refer to a physical file on some device (not a string you are dealing with in your code, or a JavaScript object). The browser has no access to physical files on your machine. It cannot read or write them. Actually, the browser does not even really have the notion of a "file". Thus, you cannot just read or write some JSON file on your local machine. If you are sending JSON to and from a server, then of course, the server might be storing the JSON as a file, but more likely the server would be constructing the JSON based on some ajax request, based on data it retrieves from a database, or decoding the JSON in some ajax request, and then storing the relevant data back into its database.

Do you really have a "JSON file", and if so, where does it exist and where did you get it from? Do you have a JSON-format string, that you need to parse, mainpulate, and turn back into a new JSON-format string? Do you need to get JSON from the server, and modify it and then send it back to the server? Or is your "JSON file" actually just a JavaScript object, that you simply need to manipulate with normal JavaScript logic?

How do I keep a label centered in WinForms?

Set Label's AutoSize property to False, TextAlign property to MiddleCenter and Dock property to Fill.

Hash table runtime complexity (insert, search and delete)

Ideally, a hashtable is O(1). The problem is if two keys are not equal, however they result in the same hash.

For example, imagine the strings "it was the best of times it was the worst of times" and "Green Eggs and Ham" both resulted in a hash value of 123.

When the first string is inserted, it's put in bucket 123. When the second string is inserted, it would see that a value already exists for bucket 123. It would then compare the new value to the existing value, and see they are not equal. In this case, an array or linked list is created for that key. At this point, retrieving this value becomes O(n) as the hashtable needs to iterate through each value in that bucket to find the desired one.

For this reason, when using a hash table, it's important to use a key with a really good hash function that's both fast and doesn't often result in duplicate values for different objects.

Make sense?

Firebase (FCM) how to get token

Important information.

if google play service hung or not running, then fcm return token = null

If play service working properly then FirebaseInstanceId.getInstance().getToken() method returns token

Log.d("FCMToken", "token "+ FirebaseInstanceId.getInstance().getToken());

Handle Button click inside a row in RecyclerView

I wanted a solution that did not create any extra objects (ie listeners) that would have to be garbage collected later, and did not require nesting a view holder inside an adapter class.

In the ViewHolder class

private static class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

        private final TextView ....// declare the fields in your view
        private ClickHandler ClickHandler;

        public MyHolder(final View itemView) {
            super(itemView);
            nameField = (TextView) itemView.findViewById(R.id.name);
            //find other fields here...
            Button myButton = (Button) itemView.findViewById(R.id.my_button);
            myButton.setOnClickListener(this);
        }
        ...
        @Override
        public void onClick(final View view) {
            if (clickHandler != null) {
                clickHandler.onMyButtonClicked(getAdapterPosition());
            }
        }

Points to note: the ClickHandler interface is defined, but not initialized here, so there is no assumption in the onClick method that it was ever initialized.

The ClickHandler interface looks like this:

private interface ClickHandler {
    void onMyButtonClicked(final int position);
} 

In the adapter, set an instance of 'ClickHandler' in the constructor, and override onBindViewHolder, to initialize `clickHandler' on the view holder:

private class MyAdapter extends ...{

    private final ClickHandler clickHandler;

    public MyAdapter(final ClickHandler clickHandler) {
        super(...);
        this.clickHandler = clickHandler;
    }

    @Override
    public void onBindViewHolder(final MyViewHolder viewHolder, final int position) {
        super.onBindViewHolder(viewHolder, position);
        viewHolder.clickHandler = this.clickHandler;
    }

Note: I know that viewHolder.clickHandler is potentially getting set multiple times with the exact same value, but this is cheaper than checking for null and branching, and there is no memory cost, just an extra instruction.

Finally, when you create the adapter, you are forced to pass a ClickHandlerinstance to the constructor, as so:

adapter = new MyAdapter(new ClickHandler() {
    @Override
    public void onMyButtonClicked(final int position) {
        final MyModel model = adapter.getItem(position);
        //do something with the model where the button was clicked
    }
});

Note that adapter is a member variable here, not a local variable

What's the shebang/hashbang (#!) in Facebook and new Twitter URLs for?

Answers above describe well why and how it is used on twitter and facebook, what I missed is explanation what # does by default...

On a 'normal' (not a single page application) you can do anchoring with hash to any element that has id by placing that elements id in url after hash #

Example:

(on Chrome) Click F12 or Rihgt Mouse and Inspect element

enter image description here

then take id="answer-10831233" and add to url like following

https://stackoverflow.com/questions/3009380/whats-the-shebang-hashbang-in-facebook-and-new-twitter-urls-for#answer-10831233

and you will get a link that jumps to that element on the page

What's the shebang/hashbang (#!) in Facebook and new Twitter URLs for?

By using # in a way described in the answers above you are introducing conflicting behaviour... although I wouldn't loose sleep over it... since Angular it became somewhat of a standard....

docker-compose up for only certain containers

One good solution is to run only desired services like this:

docker-compose up --build $(<services.txt)

and services.txt file look like this:

services1 services2, etc

of course if dependancy (depends_on), need to run related services together.

--build is optional, just for example.

How can I insert values into a table, using a subquery with more than one result?

If you are inserting one record into your table, you can do

INSERT INTO yourTable 
VALUES(value1, value2)

But since you want to insert more than one record, you can use a SELECT FROM in your SQL statement.

so you will want to do this:

INSERT INTO prices (group, id, price) 
SELECT 7, articleId, 1.50
from article 
WHERE name LIKE 'ABC%'

Getting values from query string in an url using AngularJS $location

If your $location.search() is not working, then make sure you have the following:

1) html5Mode(true) is configured in app's module config

appModule.config(['$locationProvider', function($locationProvider) {
   $locationProvider.html5Mode(true);
}]);

2) <base href="/"> is present in your HTML

<head>
  <base href="/">
  ...
</head>

References:

  1. base href="/"
  2. html5Mode

How to stick <footer> element at the bottom of the page (HTML5 and CSS3)?

Here is an example using css3:

CSS:

html, body {
    height: 100%;
    margin: 0;
}
#wrap {
    padding: 10px;
    min-height: -webkit-calc(100% - 100px);     /* Chrome */
    min-height: -moz-calc(100% - 100px);     /* Firefox */
    min-height: calc(100% - 100px);     /* native */
}
.footer {
    position: relative;
    clear:both;
}

HTML:

<div id="wrap">
    body content....
</div>
<footer class="footer">
    footer content....
</footer>

jsfiddle

Update
As @Martin pointed, the ´position: relative´ is not mandatory on the .footer element, the same for clear:both. These properties are only there as an example. So, the minimum css necessary to stick the footer on the bottom should be:

html, body {
    height: 100%;
    margin: 0;
}
#wrap {
    min-height: -webkit-calc(100% - 100px);     /* Chrome */
    min-height: -moz-calc(100% - 100px);     /* Firefox */
    min-height: calc(100% - 100px);     /* native */
}

Also, there is an excellent article at css-tricks showing different ways to do this: https://css-tricks.com/couple-takes-sticky-footer/

Package doesn't exist error in intelliJ

In my case the only thing that worked is:

mvn idea:idea

The good thing is that you don't have to delete .idea folder or .iml files and loose all configuration. Everything will be preserved.

(Possibly something like gradle idea works for gradle too).

php - push array into array - key issue

first convert your array too JSON

while($query->fetch()){
   $col[] = json_encode($row,JSON_UNESCAPED_UNICODE);
}

then vonvert back it to array

foreach($col as &$array){
   $array = json_decode($array,true);
}

good luck

How to check if an item is selected from an HTML drop down list?

Select select = new Select(_element);
List<WebElement> selectedOptions = select.getAllSelectedOptions();

if(selectedOptions.size() > 0){
    return true;
}else{
    return false;
}

How to access single elements in a table in R

Maybe not so perfect as above ones, but I guess this is what you were looking for.

data[1:1,3:3]    #works with positive integers
data[1:1, -3:-3] #does not work, gives the entire 1st row without the 3rd element
data[i:i,j:j]    #given that i and j are positive integers

Here indexing will work from 1, i.e,

data[1:1,1:1]    #means the top-leftmost element

Setting default values for columns in JPA

In 2017, JPA 2.1 still has only @Column(columnDefinition='...') to which you put the literal SQL definition of the column. Which is quite unflexible and forces you to also declare the other aspects like type, short-circuiting the JPA implementation's view on that matter.

Hibernate though, has this:

@Column(length = 4096, nullable = false)
@org.hibernate.annotations.ColumnDefault("")
private String description;

Identifies the DEFAULT value to apply to the associated column via DDL.

Two notes to that:

1) Don't be afraid of going non-standard. Working as a JBoss developer, I've seen quite some specification processes. The specification is basically the baseline that the big players in given field are willing to commit to support for the next decade or so. It's true for security, for messaging, ORM is no difference (although JPA covers quite a lot). My experience as a developer is that in a complex application, sooner or later you will need a non-standard API anyway. And @ColumnDefault is an example when it outweigts the negatives of using a non-standard solution.

2) It's nice how everyone waves @PrePersist or constructor member initialization. But that's NOT the same. How about bulk SQL updates? How about statements that don't set the column? DEFAULT has it's role and that's not substitutable by initializing a Java class member.

Setting Windows PATH for Postgres tools

Incase any one still wondering how to add environment variables then please use this link to add variables. Link: https://sqlbackupandftp.com/blog/setting-windows-path-for-postgres-tools

Saving plots (AxesSubPlot) generated from python pandas with matplotlib's savefig

The gcf method is depricated in V 0.14, The below code works for me:

plot = dtf.plot()
fig = plot.get_figure()
fig.savefig("output.png")

PHP file_get_contents() and setting request headers

Yes.

When calling file_get_contents on a URL, one should use the stream_create_context function, which is fairly well documented on php.net.

This is more or less exactly covered on the following page at php.net in the user comments section: http://php.net/manual/en/function.stream-context-create.php

What is the difference between document.location.href and document.location?

As of June 14th 2013 (HTML5), there is a significant difference

Browser : Chrome 27.X.X

References: document.location, window.location (MDN)


document.location

type: Object

The object when called by itself document.location return its origin + pathname properties concatenated.

To retrieve just the URL as a string, the read-only document.URL property can be used.

ancestorOrigins: DOMStringList
assign: function () { [native code] }
hash: ""
host: "stackoverflow.com"
hostname: "stackoverflow.com"
href: "http://stackoverflow.com/questions/2652816/what-is-the-difference-between-document-location-href-and-document-location?rq=1"
origin: "http://stackoverflow.com"
pathname: "/questions/2652816/what-is-the-difference-between-document-location-href-and-document-location"
port: ""
protocol: "http:"
reload: function () { [native code] }
replace: function () { [native code] }
search: "?rq=1"
toString: function toString() { [native code] }
valueOf: function valueOf() { [native code] }

document.location.href

type: string

http://stackoverflow.com/questions/2652816/what-is-the-difference-between-document-location-href-and-document-location?rq=1

What is the cause for "angular is not defined"

You have to put your script tag after the one that references Angular. Move it out of the head:

<script type="text/javascript" src="angular.min.js"></script>
<script type="text/javascript" src="main.js"></script>

The way you've set it up now, your script runs before Angular is loaded on the page.

Rails 4 Authenticity Token

Came across the same problem. Fixed it by adding to my controller:

      skip_before_filter :verify_authenticity_token, if: :json_request?

How do I return multiple values from a function in C?

Option 1: Declare a struct with an int and string and return a struct variable.

struct foo {    
 int bar1;
 char bar2[MAX];
};

struct foo fun() {
 struct foo fooObj;
 ...
 return fooObj;
}

Option 2: You can pass one of the two via pointer and make changes to the actual parameter through the pointer and return the other as usual:

int fun(char **param) {
 int bar;
 ...
 strcpy(*param,"....");
 return bar;
}

or

 char* fun(int *param) {
 char *str = /* malloc suitably.*/
 ...
 strcpy(str,"....");
 *param = /* some value */
 return str;
}

Option 3: Similar to the option 2. You can pass both via pointer and return nothing from the function:

void fun(char **param1,int *param2) {
 strcpy(*param1,"....");
 *param2 = /* some calculated value */
}

what is the difference between json and xml

They are both data formats for hierarchical data, so while the syntax is quite different, the structure is similar. Example:

JSON:

{
  "persons": [
    {
      "name": "Ford Prefect",
      "gender": "male"
    },
    {
      "name": "Arthur Dent",
      "gender": "male"
    },
    {
      "name": "Tricia McMillan",
      "gender": "female"
    }
  ]
}

XML:

<persons>
  <person>
    <name>Ford Prefect</name>
    <gender>male</gender>
  </person>
  <person>
    <name>Arthur Dent</name>
    <gender>male</gender>
  </person>
  <person>
    <name>Tricia McMillan</name>
    <gender>female</gender>
  </person>
</persons>

The XML format is more advanced than shown by the example, though. You can for example add attributes to each element, and you can use namespaces to partition elements. There are also standards for defining the format of an XML file, the XPATH language to query XML data, and XSLT for transforming XML into presentation data.

The XML format has been around for some time, so there is a lot of software developed for it. The JSON format is quite new, so there is a lot less support for it.

While XML was developed as an independent data format, JSON was developed specifically for use with Javascript and AJAX, so the format is exactly the same as a Javascript literal object (that is, it's a subset of the Javascript code, as it for example can't contain expressions to determine values).

Make $JAVA_HOME easily changable in Ubuntu

This will probably solve your problem: https://help.ubuntu.com/community/EnvironmentVariables

Session-wide environment variables

In order to set environment variables in a way that affects a particular user's environment, one should not place commands to set their values in particular shell script files in the user's home directory, but use:

~/.pam_environment - This file is specifically meant for setting a user's environment. It is not a script file, but rather consists of assignment expressions, one per line.

Not recommended:

~/.profile - This is probably the best file for placing environment variable assignments in, since it gets executed automatically by the DisplayManager during the startup process desktop session as well as by the login shell when one logs-in from the textual console.

What is the right way to write my script 'src' url for a local development environment?

I believe the browser is looking for those assets FROM the root of the webserver. This is difficult because it is easy to start developing on your machine WITHOUT actually using a webserver ( just by loading local files through your browser)

You could start by packaging your html and css/js together?

a directory structure something like:

-yourapp
  - index.html
  - assets
    - css
    - js
      - myPage.js

Then your script tag (from index.html) could look like

<script src="assets/js/myPage.js"></script>

An added benifit of packaging your html and assets in one directory is that you can copy the directory and give it to someone else or put it on another machine and it will work great.

How to access nested elements of json object using getJSONArray method

This is for Nikola.

    public static JSONObject setProperty(JSONObject js1, String keys, String valueNew) throws JSONException {
    String[] keyMain = keys.split("\\.");
    for (String keym : keyMain) {
        Iterator iterator = js1.keys();
        String key = null;
        while (iterator.hasNext()) {
            key = (String) iterator.next();
            if ((js1.optJSONArray(key) == null) && (js1.optJSONObject(key) == null)) {
                if ((key.equals(keym)) && (js1.get(key).toString().equals(valueMain))) {
                    js1.put(key, valueNew);
                    return js1;
                }
            }
            if (js1.optJSONObject(key) != null) {
                if ((key.equals(keym))) {
                    js1 = js1.getJSONObject(key);
                    break;
                }
            }
            if (js1.optJSONArray(key) != null) {
                JSONArray jArray = js1.getJSONArray(key);
                JSONObject j;
                for (int i = 0; i < jArray.length(); i++) {
                    js1 = jArray.getJSONObject(i);
                    break;
                }
            }
        }
    }
    return js1;
}


public static void main(String[] args) throws IOException, JSONException {
    String text = "{ "key1":{ "key2":{ "key3":{ "key4":[ { "fieldValue":"Empty", "fieldName":"Enter Field Name 1" }, { "fieldValue":"Empty", "fieldName":"Enter Field Name 2" } ] } } } }";
    JSONObject json = new JSONObject(text);
    setProperty(json, "ke1.key2.key3.key4.fieldValue", "nikola");
    System.out.println(json.toString(4));

}

If it's help bro,Do not forget to up for my reputation)))

Conda uninstall one package and one package only

You can use conda remove --force.

The documentation says:

--force               Forces removal of a package without removing packages
                      that depend on it. Using this option will usually
                      leave your environment in a broken and inconsistent
                      state

What's a redirect URI? how does it apply to iOS app for OAuth2.0?

redirected uri is the location where the user will be redirected after successfully login to your app. for example to get access token for your app in facebook you need to subimt redirected uri which is nothing only the app Domain that your provide when you create your facebook app.

How can I get terminal output in python?

The recommended way in Python 3.5 and above is to use subprocess.run():

from subprocess import run
output = run("pwd", capture_output=True).stdout

How to convert string to Date in Angular2 \ Typescript?

You can use date filter to convert in date and display in specific format.

In .ts file (typescript):

let dateString = '1968-11-16T00:00:00' 
let newDate = new Date(dateString);

In HTML:

{{dateString |  date:'MM/dd/yyyy'}}

Below are some formats which you can implement :

Backend:

public todayDate = new Date();

HTML :

<select>
<option value=""></option>
<option value="MM/dd/yyyy">[{{todayDate | date:'MM/dd/yyyy'}}]</option>
<option value="EEEE, MMMM d, yyyy">[{{todayDate | date:'EEEE, MMMM d, yyyy'}}]</option>
<option value="EEEE, MMMM d, yyyy h:mm a">[{{todayDate | date:'EEEE, MMMM d, yyyy h:mm a'}}]</option>
<option value="EEEE, MMMM d, yyyy h:mm:ss a">[{{todayDate | date:'EEEE, MMMM d, yyyy h:mm:ss a'}}]</option>
<option value="MM/dd/yyyy h:mm a">[{{todayDate | date:'MM/dd/yyyy h:mm a'}}]</option>
<option value="MM/dd/yyyy h:mm:ss a">[{{todayDate | date:'MM/dd/yyyy h:mm:ss a'}}]</option>
<option value="MMMM d">[{{todayDate | date:'MMMM d'}}]</option>   
<option value="yyyy-MM-ddTHH:mm:ss">[{{todayDate | date:'yyyy-MM-ddTHH:mm:ss'}}]</option>
<option value="h:mm a">[{{todayDate | date:'h:mm a'}}]</option>
<option value="h:mm:ss a">[{{todayDate | date:'h:mm:ss a'}}]</option>      
<option value="EEEE, MMMM d, yyyy hh:mm:ss a">[{{todayDate | date:'EEEE, MMMM d, yyyy hh:mm:ss a'}}]</option>
<option value="MMMM yyyy">[{{todayDate | date:'MMMM yyyy'}}]</option> 
</select>

Can an angular directive pass arguments to functions in expressions specified in the directive's attributes?

If you declare your callback as mentioned by @lex82 like

callback = "callback(item.id, arg2)"

You can call the callback method in the directive scope with object map and it would do the binding correctly. Like

scope.callback({arg2:"some value"});

without requiring for $parse. See my fiddle(console log) http://jsfiddle.net/k7czc/2/

Update: There is a small example of this in the documentation:

& or &attr - provides a way to execute an expression in the context of the parent scope. If no attr name is specified then the attribute name is assumed to be the same as the local name. Given and widget definition of scope: { localFn:'&myAttr' }, then isolate scope property localFn will point to a function wrapper for the count = count + value expression. Often it's desirable to pass data from the isolated scope via an expression and to the parent scope, this can be done by passing a map of local variable names and values into the expression wrapper fn. For example, if the expression is increment(amount) then we can specify the amount value by calling the localFn as localFn({amount: 22}).

How to click on hidden element in Selenium WebDriver?

overflow:hidden 

does not always mean that the element is hidden or non existent in the DOM, it means that the overflowing chars that do not fit in the element are being trimmed. Basically it means that do not show scrollbar even if it should be showed, so in your case the link with text

Plastic Spiral Bind

could possibly be shown as "Plastic Spir..." or similar. So it is possible, that this linkText indeed is non existent.

So you can probably try:

driver.findElement(By.partialLinkText("Plastic ")).click();

or xpath:

//a[contains(@title, \"Plastic Spiral Bind\")]

Return multiple values from a SQL Server function

Another option would be to use a procedure with output parameters - Using a Stored Procedure with Output Parameters

Android: ProgressDialog.show() crashes with getApplicationContext

For Activities shown within TabActivities use getParent()

final AlertDialog.Builder builder = new AlertDialog.Builder(getParent());

instead of

final AlertDialog.Builder builder = new AlertDialog.Builder(this);

ImportError: DLL load failed: %1 is not a valid Win32 application

You could try installing the 32 bit version of opencv

Taking the record with the max date

You could also use:

SELECT t.*
  FROM 
        TABLENAME t
    JOIN
        ( SELECT A, MAX(col_date) AS col_date
          FROM TABLENAME
          GROUP BY A
        ) m
      ON  m.A = t.A
      AND m.col_date = t.col_date

Simple JavaScript Checkbox Validation

For now no jquery or php needed. Use just "required" HTML5 input attrbute like here

 <form>
        <p>
            <input class="form-control" type="text" name="email" />
            <input type="submit" value="ok" class="btn btn-success" name="submit" />
            <input type="hidden" name="action" value="0" />
        </p>
        <p><input type="checkbox" required name="terms">I have read and accept <a href="#">SOMETHING Terms and Conditions</a></p>
 </form>

This will validate and prevent any submit before checkbox is opt in. Language independent solution because its generated by users web browser.

How do I manually create a file with a . (dot) prefix in Windows? For example, .htaccess

Even if you don't have any third party editor (Notepad++ etc.) then also you can create files with dot as prefix.

To create .htaccess file, first create htaccess.txt file with Context Menu > New Text Document.

Then press Alt + D (Windows 7) and Ctrl + C to copy the path from the Address bar of Windows Explorer.

Then go to command line and type code as below to rename your file:

rename C:\path\to\htaccess.txt .htaccess

Now you have a blank .htaccess without opening it in any editor.

Hope this helps you out.

Selecting a row in DataGridView programmatically

In Visual Basic, do this to select a row in a DataGridView; the selected row will appear with a highlighted color but note that the cursor position will not change:

Grid.Rows(0).Selected = True

Do this change the position of the cursor:

Grid.CurrentCell = Grid.Rows(0).Cells(0)

Combining the lines above will position the cursor and select a row. This is the standard procedure for focusing and selecting a row in a DataGridView:

Grid.CurrentCell = Grid.Rows(0).Cells(0)
Grid.Rows(0).Selected = True

Reading a text file with SQL Server

BULK INSERT dbo.temp 

FROM 'c:\temp\file.txt' --- path file in db server 

WITH 

  (
     ROWTERMINATOR ='\n'
  )

it work for me but save as by editplus to ansi encoding for multilanguage

Python: Find in list

Check there are no additional/unwanted whites space in the items of the list of strings. That's a reason that can be interfering explaining the items cannot be found.

Make an html number input always display 2 decimal places

Pure html is not able to do what you want. My suggestion would be to write a simple javascript function to do the roudning for you.

redirect while passing arguments

You could pass the messages as explicit URL parameter (appropriately encoded), or store the messages into session (cookie) variable before redirecting and then get the variable before rendering the template. For example:

from flask import session, url_for

def do_baz():
    messages = json.dumps({"main":"Condition failed on page baz"})
    session['messages'] = messages
    return redirect(url_for('.do_foo', messages=messages))

@app.route('/foo')
def do_foo():
    messages = request.args['messages']  # counterpart for url_for()
    messages = session['messages']       # counterpart for session
    return render_template("foo.html", messages=json.loads(messages))

(encoding the session variable might not be necessary, flask may be handling it for you, but can't recall the details)

Or you could probably just use Flask Message Flashing if you just need to show simple messages.

Write bytes to file

If I understand you correctly, this should do the trick. You'll need add using System.IO at the top of your file if you don't already have it.

public bool ByteArrayToFile(string fileName, byte[] byteArray)
{
    try
    {
        using (var fs = new FileStream(fileName, FileMode.Create, FileAccess.Write))
        {
            fs.Write(byteArray, 0, byteArray.Length);
            return true;
        }
    }
    catch (Exception ex)
    {
        Console.WriteLine("Exception caught in process: {0}", ex);
        return false;
    }
}

Git, fatal: The remote end hung up unexpectedly

Based on the protocol you are using to push to your repo

HTTP

git config --global http.postBuffer 157286400

References:

SSH

Add the following in ~/.ssh/config file in your linux machine

Host your-gitlab-server.com
  ServerAliveInterval 60
  ServerAliveCountMax 5
  IPQoS throughput

References:

Use LINQ to get items in one List<>, that are not in another List<>

Here is a working example that get IT skills that a job candidate does not already have.

//Get a list of skills from the Skill table
IEnumerable<Skill> skillenum = skillrepository.Skill;
//Get a list of skills the candidate has                   
IEnumerable<CandSkill> candskillenum = candskillrepository.CandSkill
       .Where(p => p.Candidate_ID == Candidate_ID);             
//Using the enum lists with LINQ filter out the skills not in the candidate skill list
IEnumerable<Skill> skillenumresult = skillenum.Where(p => !candskillenum.Any(p2 => p2.Skill_ID == p.Skill_ID));
//Assign the selectable list to a viewBag
ViewBag.SelSkills = new SelectList(skillenumresult, "Skill_ID", "Skill_Name", 1);

In git, what is the difference between merge --squash and rebase?

Let's start by the following example:

enter image description here

Now we have 3 options to merge changes of feature branch into master branch:

  1. Merge commits
    Will keep all commits history of the feature branch and move them into the master branch
    Will add extra dummy commit.

  2. Rebase and merge
    Will append all commits history of the feature branch in the front of the master branch
    Will NOT add extra dummy commit.

  3. Squash and merge
    Will group all feature branch commits into one commit then append it in the front of the master branch
    Will add extra dummy commit.

You can find below how the master branch will look after each one of them.

enter image description here

In all cases:
We can safely DELETE the feature branch.

What's the difference between jquery.js and jquery.min.js?

If you use use the Jquery from Google CDN, seriously it will improve the performance by 5 to 10 times the one which you add into your page, which gets downloaded. And also, you will get the latest version of the Jquery files.

The difference between both files i.e. jquery.js and jquery.min.js is just the file size, due to this the files are getting downloaded faster. :)

Java 8 method references: provide a Supplier capable of supplying a parameterized result

It appears that you can throw only RuntimeException from the method orElseThrow. Otherwise you will get an error message like MyException cannot be converted to java.lang.RuntimeException

Update:- This was an issue with an older version of JDK. I don't see this issue with the latest versions.

Git checkout: updating paths is incompatible with switching branches

Alternate syntax,

git fetch origin remote_branch_name:local_branch_name

Get current URL from IFRAME

Hope this will help some how in your case, I suffered with the exact same problem, and just used localstorage to share the data between parent window and iframe. So in parent window you can:

localStorage.setItem("url", myUrl);

And in code where iframe source is just get this data from localstorage:

localStorage.getItem('url');

Saved me a lot of time. As far as i can see the only condition is access to the parent page code. Hope this will help someone.

How to disable registration new users in Laravel

Heres my solution as of 5.4:

//Auth::routes();
// Authentication Routes...
Route::get('login', 'Auth\LoginController@showLoginForm')->name('login');
Route::post('login', 'Auth\LoginController@login');
Route::post('logout', 'Auth\LoginController@logout')->name('logout');

// Registration Routes...
//Route::get('register', 'Auth\RegisterController@showRegistrationForm')->name('register');
//Route::post('register', 'Auth\RegisterController@register');

// Password Reset Routes...
Route::get('password/reset', 'Auth\ForgotPasswordController@showLinkRequestForm')->name('password.request');
Route::post('password/email', 'Auth\ForgotPasswordController@sendResetLinkEmail')->name('password.email');
Route::get('password/reset/{token}', 'Auth\ResetPasswordController@showResetForm')->name('password.reset');
Route::post('password/reset', 'Auth\ResetPasswordController@reset');

Notice I've commented out Auth::routes() and the two registration routes.

Important: you must also make sure you remove all instances of route('register') in your app.blade layout, or Laravel will throw an error.

Select Multiple Fields from List in Linq

You can make it a KeyValuePair, so it will return a "IEnumerable<KeyValuePair<string, string>>"

So, it will be like this:

.Select(i => new KeyValuePair<string, string>(i.category_id, i.category_name )).Distinct();

Tensorflow 2.0 - AttributeError: module 'tensorflow' has no attribute 'Session'

If this is your code, the correct solution is to rewrite it to not use Session(), since that's no longer necessary in TensorFlow 2

If this is just code you're running, you can downgrade to TensorFlow 1 by running

pip3 install --upgrade --force-reinstall tensorflow-gpu==1.15.0 

(or whatever the latest version of TensorFlow 1 is)

What are the benefits to marking a field as `readonly` in C#?

There are no apparent performance benefits to using readonly, at least none that I've ever seen mentioned anywhere. It's just for doing exactly as you suggest, for preventing modification once it has been initialised.

So it's beneficial in that it helps you write more robust, more readable code. The real benefit of things like this come when you're working in a team or for maintenance. Declaring something as readonly is akin to putting a contract for that variable's usage in the code. Think of it as adding documentation in the same way as other keywords like internal or private, you're saying "this variable should not be modified after initialisation", and moreover you're enforcing it.

So if you create a class and mark some member variables readonly by design, then you prevent yourself or another team member making a mistake later on when they're expanding upon or modifying your class. In my opinion, that's a benefit worth having (at the small expense of extra language complexity as doofledorfer mentions in the comments).

Get first element in PHP stdObject

Update PHP 7.4

Curly brace access syntax is deprecated since PHP 7.4

Update 2019

Moving on to the best practices of OOPS, @MrTrick's answer must be marked as correct, although my answer provides a hacked solution its not the best method.

Simply iterate its using {}

Example:

$videos{0}->id

This way your object is not destroyed and you can easily iterate through object.

For PHP 5.6 and below use this

$videos{0}['id']

Both array() and the stdClass objects can be accessed using the current() key() next() prev() reset() end() functions.

So, if your object looks like

object(stdClass)#19 (3) {
  [0]=>
  object(stdClass)#20 (22) {
    ["id"]=>
    string(1) "123"
  etc...

Then you can just do;

$id = reset($obj)->id; //Gets the 'id' attr of the first entry in the object

If you need the key for some reason, you can do;

reset($obj); //Ensure that we're at the first element
$key = key($obj);

Hope that works for you. :-) No errors, even in super-strict mode, on PHP 5.4


2022 Update:
After PHP 7.4, using current(), end(), etc functions on objects is deprecated.

In newer versions of PHP, use the ArrayIterator class:

$objIterator = new ArrayIterator($obj);

$id = $objIterator->current()->id; // Gets the 'id' attr of the first entry in the object

$key = $objIterator->key(); // and gets the key

How to change Java version used by TOMCAT?

In Eclipse it is very easy to point Tomcat to a new JVM (in this example JRE6). My problem was I couldn't find where to do it. Here is the trick:

  1. On the ECLIPSE top menu FILE pull down tab, select NEW, -->Other
  2. ...on the New Server: Select A Wizard window, select: Server-> Server... click NEXT
  3. . on the New Server: Define a New Server window, select Apache> Tomcat 7 Server
  4. ..now click the line in blue and underlined entitled: Configure Runtime Environments
  5. on the Server Runtime Environments window,
  6. ..select Apache, expand it(click on the arrow to the left), select TOMCAT v7.0, and click EDIT.
  7. you will see a window called EDIT SERVER RUNTIME ENVIRONMENT: TOMCAT SERVER
  8. On this screen there is a pulldown labeled JREs.
  9. You should find your JRE listed like JRE1.6.0.33. If not use the Installed JRE button.
  10. Select the desired JRE. Click the FINISH button.
  11. Gracefully exit, in the Server: Server Runtime Environments window, click OK
  12. in the New Server: Define a new Server window, hit NEXT
  13. in the New Server: Add and Remove Window, select apps and install them on the server.
  14. in the New Server: Add and Remove Window, click Finish

That's all. Interesting, only steps 7-10 seem to matter, and they will change the JRE used on all servers you have previously defined to use TOMCAT v7.0. The rest of the steps are just because I can't find any other way to get to the screen except by defining a new server. Does anyone else know an easier way?

What does if __name__ == "__main__": do?

There are a number of variables that the system (Python interpreter) provides for source files (modules). You can get their values anytime you want, so, let us focus on the __name__ variable/attribute:

When Python loads a source code file, it executes all of the code found in it. (Note that it doesn't call all of the methods and functions defined in the file, but it does define them.)

Before the interpreter executes the source code file though, it defines a few special variables for that file; __name__ is one of those special variables that Python automatically defines for each source code file.

If Python is loading this source code file as the main program (i.e. the file you run), then it sets the special __name__ variable for this file to have a value "__main__".

If this is being imported from another module, __name__ will be set to that module's name.

So, in your example in part:

if __name__ == "__main__":
   lock = thread.allocate_lock()
   thread.start_new_thread(myfunction, ("Thread #: 1", 2, lock))
   thread.start_new_thread(myfunction, ("Thread #: 2", 2, lock))

means that the code block:

lock = thread.allocate_lock()
thread.start_new_thread(myfunction, ("Thread #: 1", 2, lock))
thread.start_new_thread(myfunction, ("Thread #: 2", 2, lock))

will be executed only when you run the module directly; the code block will not execute if another module is calling/importing it because the value of __name__ will not equal to "main" in that particular instance.

Hope this helps out.

What's the difference between a Python module and a Python package?

A module is a single file (or files) that are imported under one import and used. e.g.

import my_module

A package is a collection of modules in directories that give a package hierarchy.

from my_package.timing.danger.internets import function_of_love

Documentation for modules

Introduction to packages

Random strings in Python

try importing the below package from random import*

How do I close an open port from the terminal on the Mac?

You can also use this first command to kill a process that owns a particular port:

sudo netstat -ap | grep :<port_number>

For example, say this process holds port 8000 TCP, then running the command:

sudo netstat -ap | grep :8000

will output the line corresponding to the process holding port 8000, for example:

tcp  0  0 *:8000   *:* LISTEN  4683/procHoldingPort

In this case, procHoldingPort is the name of the process that opened the port, 4683 is its pid, and 8000 (note that it is TCP) is the port number it holds (which you wish to close).

Then kill the process, following the above example:

kill  4683

As others mentioned here out, if that doesn't work (you can try using kill with -9 as an argument):

kill -9 4683

Again, in general, it's better to avoid sending SIGKILL (-9) if you can.

How to clean old dependencies from maven repositories?

Short answer - Deleted .m2 folder in {user.home}. E.g. in windows 10 user home is C:\Users\user1. Re-build your project using mvn clean package. Only those dependencies would remain, which are required by the projects.

Long Answer - .m2 folder is just like a normal folder and the content of the folder is built from different projects. I think there is no way to figure out automatically that which library is "old". In fact old is a vague word. There could be so many reasons when a previous version of a library is used in a project, hence determining which one is unused is not possible.

All you could do, is to delete the .m2 folder and re-build all of your projects and then the folder would automatically build with all the required library.

If you are concern about only a particular version of a library to be used in all the projects; it is important that the project's pom should also update to latest version. i.e. if different POMs refer different versions of the library, all will get downloaded in .m2.

Methods vs Constructors in Java

The Major difference is Given Below -

1: Constructor must have same name as the class name while this is not the case of methods

class Calendar{
    int year = 0;
    int month= 0;

    //constructor
    public Calendar(int year, int month){
        this.year = year;
        this.month = month;
        System.out.println("Demo Constructor");
    }

    //Method
    public void Display(){

        System.out.println("Demo method");
    }
} 

2: Constructor initializes objects of a class whereas method does not. Methods performs operations on objects that already exist. In other words, to call a method we need an object of the class.

public class Program {

    public static void main(String[] args) {

        //constructor will be called on object creation
        Calendar ins =  new Calendar(25, 5);

        //Methods will be called on object created
        ins.Display();

    }

}

3: Constructor does not have return type but a method must have a return type

class Calendar{

    //constructor – no return type
    public Calendar(int year, int month){

    }

    //Method have void return type
    public void Display(){

        System.out.println("Demo method");
    }
} 

What is the difference between a static and a non-static initialization code block

You will not write code into a static block that needs to be invoked anywhere in your program. If the purpose of the code is to be invoked then you must place it in a method.

You can write static initializer blocks to initialize static variables when the class is loaded but this code can be more complex..

A static initializer block looks like a method with no name, no arguments, and no return type. Since you never call it it doesn't need a name. The only time its called is when the virtual machine loads the class.

How to upper case every first letter of word in a string?

import java.util.Scanner;
public class CapitolizeOneString {

    public static void main(String[] args)
    {
        Scanner  scan = new Scanner(System.in);
        System.out.print(" Please enter Your word      = ");
        String str=scan.nextLine();

        printCapitalized( str );
    }  // end main()

    static void printCapitalized( String str ) {
        // Print a copy of str to standard output, with the
        // first letter of each word in upper case.
        char ch;       // One of the characters in str.
        char prevCh;   // The character that comes before ch in the string.
        int i;         // A position in str, from 0 to str.length()-1.
        prevCh = '.';  // Prime the loop with any non-letter character.
        for ( i = 0;  i < str.length();  i++ ) {
            ch = str.charAt(i);
            if ( Character.isLetter(ch)  &&  ! Character.isLetter(prevCh) )
                System.out.print( Character.toUpperCase(ch) );
            else
                System.out.print( ch );
            prevCh = ch;  // prevCh for next iteration is ch.
        }
        System.out.println();
    }   
}  // end class

Using Powershell to stop a service remotely without WMI or remoting

Based on the built-in Powershell examples, this is what Microsoft suggests. Tested and verified:

To stop:

(Get-WmiObject Win32_Service -filter "name='IPEventWatcher'" -ComputerName Server01).StopService()

To start:

(Get-WmiObject Win32_Service -filter "name='IPEventWatcher'" -ComputerName Server01).StartService()

How to delete rows in tables that contain foreign keys to other tables

First, as a one-time data-scrubbing exercise, delete the orphaned rows e.g.

DELETE 
  FROM ReferencingTable 
 WHERE NOT EXISTS (
                   SELECT * 
                     FROM MainTable AS T1
                    WHERE T1.pk_col_1 = ReferencingTable.pk_col_1
                  );

Second, as a one-time schema-alteration exercise, add the ON DELETE CASCADE referential action to the foreign key on the referencing table e.g.

ALTER TABLE ReferencingTable DROP 
   CONSTRAINT fk__ReferencingTable__MainTable;

ALTER TABLE ReferencingTable ADD 
   CONSTRAINT fk__ReferencingTable__MainTable 
      FOREIGN KEY (pk_col_1)
      REFERENCES MainTable (pk_col_1)
      ON DELETE CASCADE;

Then, forevermore, rows in the referencing tables will automatically be deleted when their referenced row is deleted.

Is it safe to shallow clone with --depth 1, create commits, and pull updates again?

Note that Git 1.9/2.0 (Q1 2014) has removed that limitation.
See commit 82fba2b, from Nguy?n Thái Ng?c Duy (pclouds):

Now that git supports data transfer from or to a shallow clone, these limitations are not true anymore.

The documentation now reads:

--depth <depth>::

Create a 'shallow' clone with a history truncated to the specified number of revisions.

That stems from commits like 0d7d285, f2c681c, and c29a7b8 which support clone, send-pack /receive-pack with/from shallow clones.
smart-http now supports shallow fetch/clone too.

All the details are in "shallow.c: the 8 steps to select new commits for .git/shallow".

Update June 2015: Git 2.5 will even allow for fetching a single commit!
(Ultimate shallow case)


Update January 2016: Git 2.8 (Mach 2016) now documents officially the practice of getting a minimal history.
See commit 99487cf, commit 9cfde9e (30 Dec 2015), commit 9cfde9e (30 Dec 2015), commit bac5874 (29 Dec 2015), and commit 1de2e44 (28 Dec 2015) by Stephen P. Smith (``).
(Merged by Junio C Hamano -- gitster -- in commit 7e3e80a, 20 Jan 2016)

This is "Documentation/user-manual.txt"

A <<def_shallow_clone,shallow clone>> is created by specifying the git-clone --depth switch.
The depth can later be changed with the git-fetch --depth switch, or full history restored with --unshallow.

Merging inside a <<def_shallow_clone,shallow clone>> will work as long as a merge base is in the recent history.
Otherwise, it will be like merging unrelated histories and may have to result in huge conflicts.
This limitation may make such a repository unsuitable to be used in merge based workflows.

Update 2020:

  • git 2.11.1 introduced option git fetch --shallow-exclude= to prevent fetching all history
  • git 2.11.1 introduced option git fetch --shallow-since= to prevent fetching old commits.

For more on the shallow clone update process, see "How to update a git shallow clone?".


As commented by Richard Michael:

to backfill history: git pull --unshallow

And Olle Härstedt adds in the comments:

To backfill part of the history: git fetch --depth=100.

How can I get the URL of the current tab from a Google Chrome extension?

You have to check on this.

HTML

<button id="saveActionId"> Save </button>

manifest.json

  "permissions": [
    "activeTab",
    "tabs"
   ]

JavaScript
The below code will save all the urls of active window into JSON object as part of button click.

var saveActionButton = document.getElementById('saveActionId');
saveActionButton.addEventListener('click', function() {
    myArray = [];
    chrome.tabs.query({"currentWindow": true},  //{"windowId": targetWindow.id, "index": tabPosition});
    function (array_of_Tabs) {  //Tab tab
        arrayLength = array_of_Tabs.length;
        //alert(arrayLength);
        for (var i = 0; i < arrayLength; i++) {
            myArray.push(array_of_Tabs[i].url);
        }
        obj = JSON.parse(JSON.stringify(myArray));
    });
}, false);

pandas DataFrame: replace nan values with average of columns

Another option besides those above is:

df = df.groupby(df.columns, axis = 1).transform(lambda x: x.fillna(x.mean()))

It's less elegant than previous responses for mean, but it could be shorter if you desire to replace nulls by some other column function.

UL or DIV vertical scrollbar

Sometimes it is not eligible to set height to pixel values. However, it is possible to show vertical scrollbar through setting height of div to 100% and overflow to auto.

Let me show an example:

<div id="content" style="height: 100%; overflow: auto">
  <p>some text</p>
  <ul>
    <li>text</li>
    .....
    <li>text</li>
</div>

How to assign from a function which returns more than one value?

(1) list[...]<- I had posted this over a decade ago on r-help. Since then it has been added to the gsubfn package. It does not require a special operator but does require that the left hand side be written using list[...] like this:

library(gsubfn)  # need 0.7-0 or later
list[a, b] <- functionReturningTwoValues()

If you only need the first or second component these all work too:

list[a] <- functionReturningTwoValues()
list[a, ] <- functionReturningTwoValues()
list[, b] <- functionReturningTwoValues()

(Of course, if you only needed one value then functionReturningTwoValues()[[1]] or functionReturningTwoValues()[[2]] would be sufficient.)

See the cited r-help thread for more examples.

(2) with If the intent is merely to combine the multiple values subsequently and the return values are named then a simple alternative is to use with :

myfun <- function() list(a = 1, b = 2)

list[a, b] <- myfun()
a + b

# same
with(myfun(), a + b)

(3) attach Another alternative is attach:

attach(myfun())
a + b

ADDED: with and attach

Reactive forms - disabled attribute

This was my solution:

this.myForm = this._formBuilder.group({
    socDate: [[{ value: '', disabled: true }], Validators.required],
    ...
)}

<input fxFlex [matDatepicker]="picker" placeholder="Select Date" formControlName="socDate" [attr.disabled]="true" />

Error in installation a R package

In my case, the installation of nlme package is in trouble:

mv: cannot move '/home/guanshim/R/x86_64-pc-linux-gnu-library/3.4/nlme' 
to '/home/guanshim/R/x86_64-pc-linux-gnu-library/3.4/00LOCK-nlme/nlme': 
Permission denied

Using Ubuntu 18.04, CTRL+ALT+T to open a terminal window:

sudo R
install.packages('nlme')
q()

How to prevent user from typing in text field without disabling the field?

just use onkeydown="return false" to the control tag like shown below, it will not accept values from user.

    <asp:TextBox ID="txtDate" runat="server" AutoPostBack="True"
ontextchanged="txtDate_TextChanged" onkeydown="return false" >
    </asp:TextBox>

How to use filter, map, and reduce in Python 3

One of the advantages of map, filter and reduce is how legible they become when you "chain" them together to do something complex. However, the built-in syntax isn't legible and is all "backwards". So, I suggest using the PyFunctional package (https://pypi.org/project/PyFunctional/). Here's a comparison of the two:

flight_destinations_dict = {'NY': {'London', 'Rome'}, 'Berlin': {'NY'}}

PyFunctional version

Very legible syntax. You can say:

"I have a sequence of flight destinations. Out of which I want to get the dict key if city is in the dict values. Finally, filter out the empty lists I created in the process."

from functional import seq  # PyFunctional package to allow easier syntax

def find_return_flights_PYFUNCTIONAL_SYNTAX(city, flight_destinations_dict):
    return seq(flight_destinations_dict.items()) \
        .map(lambda x: x[0] if city in x[1] else []) \
        .filter(lambda x: x != []) \

Default Python version

It's all backwards. You need to say:

"OK, so, there's a list. I want to filter empty lists out of it. Why? Because I first got the dict key if the city was in the dict values. Oh, the list I'm doing this to is flight_destinations_dict."

def find_return_flights_DEFAULT_SYNTAX(city, flight_destinations_dict):
    return list(
        filter(lambda x: x != [],
               map(lambda x: x[0] if city in x[1] else [], flight_destinations_dict.items())
               )
    )

Colorplot of 2D array matplotlib

I'm afraid your posted example is not working, since X and Y aren't defined. So instead of pcolormesh let's use imshow:

import numpy as np
import matplotlib.pyplot as plt

H = np.array([[1, 2, 3, 4],
              [5, 6, 7, 8],
              [9, 10, 11, 12],
              [13, 14, 15, 16]])  # added some commas and array creation code

fig = plt.figure(figsize=(6, 3.2))

ax = fig.add_subplot(111)
ax.set_title('colorMap')
plt.imshow(H)
ax.set_aspect('equal')

cax = fig.add_axes([0.12, 0.1, 0.78, 0.8])
cax.get_xaxis().set_visible(False)
cax.get_yaxis().set_visible(False)
cax.patch.set_alpha(0)
cax.set_frame_on(False)
plt.colorbar(orientation='vertical')
plt.show()

Call of overloaded function is ambiguous

Use

p.setval(static_cast<const char *>(0));

or

p.setval(static_cast<unsigned int>(0));

As indicated by the error, the type of 0 is int. This can just as easily be cast to an unsigned int or a const char *. By making the cast manually, you are telling the compiler which overload you want.

Sum function in VBA

Range("A10") = WorksheetFunction.Sum(Worksheets("Sheet1").Range("A1", "A9"))

Where

Range("A10") is the answer cell

Range("A1", "A9") is the range to calculate

How do you set a JavaScript onclick event to a class with css

You could do it with jQuery.

$('.myClass').click(function() {
  alert('hohoho');
});

Table scroll with HTML and CSS

For whatever it's worth now: here is yet another solution:

  • create two divs within a display: inline-block
  • in the first div, put a table with only the header (header table tabhead)
  • in the 2nd div, put a table with header and data (data table / full table tabfull)
  • use JavaScript, use setTimeout(() => {/*...*/}) to execute code after render / after filling the table with results from fetch
  • measure the width of each th in the data table (using clientWidth)
  • apply the same width to the counterpart in the header table
  • set visibility of the header of the data table to hidden and set the margin top to -1 * height of data table thead pixels

With a few tweaks, this is the method to use (for brevity / simplicity, I used d3js, the same operations can be done using plain DOM):

setTimeout(() => { // pass one cycle
  d3.select('#tabfull')
    .style('margin-top', (-1 * d3.select('#tabscroll').select('thead').node().getBoundingClientRect().height) + 'px')
    .select('thead')
      .style('visibility', 'hidden');
  let widths=[]; // really rely on COMPUTED values
  d3.select('#tabfull').select('thead').selectAll('th')
    .each((n, i, nd) => widths.push(nd[i].clientWidth));
  d3.select('#tabhead').select('thead').selectAll('th')
    .each((n, i, nd) => d3.select(nd[i])
          .style('padding-right', 0)
          .style('padding-left', 0)
          .style('width', widths[i]+'px'));
})

Waiting on render cycle has the advantage of using the browser layout engine thoughout the process - for any type of header; it's not bound to special condition or cell content lengths being somehow similar. It also adjusts correctly for visible scrollbars (like on Windows)

I've put up a codepen with a full example here: https://codepen.io/sebredhh/pen/QmJvKy

java : non-static variable cannot be referenced from a static context Error

No, actually, you must declare your con2 field static:

private static java.sql.Connection con2 = null;

Edit: Correction, that won't be enough actually, you will get the same problem because your getConnection2Url method is also not static. A better solution may be to instead do the following change:

 public static void main (String[] args) { 
     new testconnect().run();
 } 

 public void run() {
     con2 = java.sql.DriverManager.getConnection(getConnectionUrl2());
 }

Shift column in pandas dataframe up by one?

First shift the column:

df['gdp'] = df['gdp'].shift(-1)

Second remove the last row which contains an NaN Cell:

df = df[:-1]

Third reset the index:

df = df.reset_index(drop=True)

Export table to file with column headers (column names) using the bcp utility and SQL Server 2008

A good alternative is SqlCmd, since it does include headers, but it has the downside of adding space padding around the data for human readability. You can combine SqlCmd with the GnuWin32 sed (stream editing) utility to cleanup the results. Here's an example that worked for me, though I can't guarantee that it's bulletproof.

First, export the data:

sqlcmd -S Server -i C:\Temp\Query.sql -o C:\Temp\Results.txt -s"    "

The -s" " is a tab character in double quotes. I found that you have to run this command via a batch file, otherwise the Windows command prompt will treat the tab as an automatic completion command and will substitute a filename in place of the tab.

If Query.sql contains:

SELECT name, object_id, type_desc, create_date
FROM MSDB.sys.views
WHERE name LIKE 'sysmail%'

then you'll see something like this in Results.txt

name                                          object_id   type_desc           create_date            
-------------------------------------------   ----------- ------------------- -----------------------
sysmail_allitems                               2001442204 VIEW                2012-07-20 17:38:27.820
sysmail_sentitems                              2017442261 VIEW                2012-07-20 17:38:27.837
sysmail_unsentitems                            2033442318 VIEW                2012-07-20 17:38:27.850
sysmail_faileditems                            2049442375 VIEW                2012-07-20 17:38:27.860
sysmail_mailattachments                        2097442546 VIEW                2012-07-20 17:38:27.933
sysmail_event_log                              2129442660 VIEW                2012-07-20 17:38:28.040

(6 rows affected)

Next, parse the text using sed:

sed -r "s/ +\t/\t/g" C:\Temp\Results.txt | sed -r "s/\t +/\t/g" | sed -r "s/(^ +| +$)//g" | sed 2d | sed $d | sed "/^$/d" > C:\Temp\Results_New.txt

Note that the 2d command means to delete the second line, the $d command means to delete the last line, and "/^$/d" deletes any blank lines.

The cleaned up file looks like this (though I replaced the tabs with | so they could be visualized here):

name|object_id|type_desc|create_date
sysmail_allitems|2001442204|VIEW|2012-07-20 17:38:27.820
sysmail_sentitems|2017442261|VIEW|2012-07-20 17:38:27.837
sysmail_unsentitems|2033442318|VIEW|2012-07-20 17:38:27.850
sysmail_faileditems|2049442375|VIEW|2012-07-20 17:38:27.860
sysmail_mailattachments|2097442546|VIEW|2012-07-20 17:38:27.933
sysmail_event_log|2129442660|VIEW|2012-07-20 17:38:28.040

Difference between two lists

var third = first.Except(second);

(you can also call ToList() after Except(), if you don't like referencing lazy collections.)

The Except() method compares the values using the default comparer, if the values being compared are of base data types, such as int, string, decimal etc.

Otherwise the comparison will be made by object address, which is probably not what you want... In that case, make your custom objects implement IComparable (or implement a custom IEqualityComparer and pass it to the Except() method).

Query an object array using linq

Add:

using System.Linq;

to the top of your file.

And then:

Car[] carList = ...
var carMake = 
    from item in carList
    where item.Model == "bmw" 
    select item.Make;

or if you prefer the fluent syntax:

var carMake = carList
    .Where(item => item.Model == "bmw")
    .Select(item => item.Make);

Things to pay attention to:

  • The usage of item.Make in the select clause instead if s.Make as in your code.
  • You have a whitespace between item and .Model in your where clause

How to detect DIV's dimension changed?

using Bharat Patil answer simply return false inside the your bind callback to prevent maximum stack error see example below:

$('#test_div').bind('resize', function(){
   console.log('resized');
   return false;
});

What is the technology behind wechat, whatsapp and other messenger apps?

WhatsApp has chosen Erlang a language built for writing scalable applications that are designed to withstand errors. Erlang uses an abstraction called the Actor model for it's concurrency - http://en.wikipedia.org/wiki/Actor_(programming_language) Instead of the more traditional shared memory approach, actors communicate by sending each other messages. Actors unlike threads are designed to be lightweight. Actors could be on the same machine or on different machines and the message passing abstractions works for both. A simple implementation of WhatsApp could be: Each user/device is represented as an actor. This actor is responsible for handling the inbox of the user, how it gets serialized to disk, the messages that the user sends and the messages that the user receives. Let's assume that Alice and Bob are friends on WhatsApp. So there is an an Alice actor and a Bob actor.

Let's trace a series of messages flowing back and forth:

Alice decides to message Bob. Alice's phone establishes a connection to the WhatsApp server and it is established that this connection is definitely from Alice's phone. Alice now sends via TCP the following message: "For Bob: A giant monster is attacking the Golden Gate Bridge". One of the WhatsApp front end server deserializes this message and delivers this message to the actor called Alice.

Alice the actor decides to serialize this and store it in a file called "Alice's Sent Messages", stored on a replicated file system to prevent data loss due to unpredictable monster rampage. Alice the actor then decides to forward this message to Bob the actor by passing it a message "Msg1 from Alice: A giant monster is attacking the Golden Gate Bridge". Alice the actor can retry with exponential back-off till Bob the actor acknowledges receiving the message.

Bob the actor eventually receives the message from (2) and decides to store this message in a file called "Bob's Inbox". Once it has stored this message durably Bob the actor will acknowledge receiving the message by sending Alice the actor a message of it's own saying "I received Msg1". Alice the actor can now stop it's retry efforts. Bob the actor then checks to see if Bob's phone has an active connection to the server. It does and so Bob the actor streams this message to the device via TCP.

Bob sees this message and replies with "For Alice: Let's create giant robots to fight them". This is now received by Bob the actor as outlined in Step 1. Bob the actor then repeats Step 2 and 3 to make sure Alice eventually receives the idea that will save mankind.

WhatsApp actually uses the XMPP protocol instead of the vastly superior protocol that I outlined above, but you get the point.

Redirecting to another page in ASP.NET MVC using JavaScript/jQuery

check the code below this will be helpful for you:

<script type="text/javascript">
  window.opener.location.href = '@Url.Action("Action", "EventstController")', window.close();
</script>

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

There is a quick method to set the syntax: Ctrl+Shift+P,then type in the input box

ss + (which type you want set)

eg: ss html +Enter

and ss means "set syntax"

it is really quicker than check in the menu's checkbox.

How do I sort strings alphabetically while accounting for value when a string is numeric?

try this

sizes.OrderBy(x => Convert.ToInt32(x)).ToList<string>();

Note: this will helpful when all are string convertable to int.....

What is a Java String's default initial value?

Any object if it is initailised , its defeault value is null, until unless we explicitly provide a default value.

How do I fix maven error The JAVA_HOME environment variable is not defined correctly?

I was facing the same issue while using mvn clean package command in Windows OS

C:\eclipse_workspace\my-sparkapp>mvn clean package
The JAVA_HOME environment variable is not defined correctly
This environment variable is needed to run this program
NB: JAVA_HOME should point to a JDK not a JRE

I resolved this issue by deleting JAVA_HOME environment variables from User Variables / System Variables then restart the laptop, then set JAVA_HOME environment variable again.

Hope it will help you.

Invoke a second script with arguments from a script

Much simpler actually:

Method 1:

Invoke-Expression $scriptPath $argumentList

Method 2:

& $scriptPath $argumentList

Method 3:

$scriptPath $argumentList

If you have spaces in your scriptPath, don't forget to escape them `"$scriptPath`"

Is there a way to link someone to a YouTube Video in HD 1080p quality?

To link to a YouTube video so it plays in HD by default, use the following URL:

https://www.youtube.com/v/VIDEOID?version=3&vq=hd1080

Change VIDEOID to the YouTube video ID that you want to link to. When someone follows the link, it will display the highest-resolution available (up to 1080p) in full-screen mode. Unfortunately, vq=hd1080 does not work on the normal YouTube site (with comments and related videos).

Convert List to Pandas Dataframe Column

You can directly call the

pd.DataFrame()

method and pass your list as parameter.

l = ['Thanks You','Its fine no problem','Are you sure']
pd.DataFrame(l)

Output:

                      0
0            Thanks You
1   Its fine no problem
2          Are you sure

And if you have multiple lists and you want to make a dataframe out of it.You can do it as following:

import pandas as pd
names =["A","B","C","D"]
salary =[50000,90000,41000,62000]
age = [24,24,23,25]
data = pd.DataFrame([names,salary,age]) #Each list would be added as a row
data = data.transpose() #To Transpose and make each rows as columns
data.columns=['Names','Salary','Age'] #Rename the columns
data.head()

Output:

    Names   Salary  Age
0       A    50000   24
1       B    90000   24
2       C    41000   23
3       D    62000   25