Programs & Examples On #Frame rate

Frame rate (also known as frame frequency) is the frequency (rate) at which an imaging device produces unique consecutive images called frames. The term applies equally well to computer graphics, video cameras, film cameras, and motion capture systems. Frame rate is most often expressed in frames per second (FPS)

How to efficiently remove duplicates from an array without using Set

public void removeDup(){ 
String[] arr = {"1","1","2","3","3"};
          boolean exists = false;
          String[] arr2 = new String[arr.length];
          int count1 = 0;
          for(int loop=0;loop<arr.length;loop++)
            {
              String val = arr[loop];
              exists = false;
              for(int loop2=0;loop2<arr2.length;loop2++)
              {     
                  if(arr2[loop2]==null)break;
                  if(arr2[loop2]==val){
                        exists = true;
                }
              }
              if(!exists) {
                    arr2[count1] = val;
                    count1++;
              }
            }
}

What's a decent SFTP command-line client for windows?

pscp and psftp are very customizable(options) and light weight. Open source to boot.

http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html

Get Enum from Description attribute

You can't extend Enum as it's a static class. You can only extend instances of a type. With this in mind, you're going to have to create a static method yourself to do this; the following should work when combined with your existing method GetDescription:

public static class EnumHelper
{
    public static T GetEnumFromString<T>(string value)
    {
        if (Enum.IsDefined(typeof(T), value))
        {
            return (T)Enum.Parse(typeof(T), value, true);
        }
        else
        {
            string[] enumNames = Enum.GetNames(typeof(T));
            foreach (string enumName in enumNames)
            {  
                object e = Enum.Parse(typeof(T), enumName);
                if (value == GetDescription((Enum)e))
                {
                    return (T)e;
                }
            }
        }
        throw new ArgumentException("The value '" + value 
            + "' does not match a valid enum name or description.");
    }
}

And the usage of it would be something like this:

Animal giantPanda = EnumHelper.GetEnumFromString<Animal>("Giant Panda");

Pinging servers in Python

My take borrowing from other answers. Attempt to simplify and minimize queries.

import platform, os

def ping(host):
    result = os.popen(' '.join(("ping", ping.param, host))).read()
    return 'TTL=' in result

ping.param = "-n 1" if platform.system().lower() == "windows" else "-c 1"

Git says local branch is behind remote branch, but it's not

You probably did some history rewriting? Your local branch diverged from the one on the server. Run this command to get a better understanding of what happened:

gitk HEAD @{u}

I would strongly recommend you try to understand where this error is coming from. To fix it, simply run:

git push -f

The -f makes this a “forced push” and overwrites the branch on the server. That is very dangerous when you are working in team. But since you are on your own and sure that your local state is correct this should be fine. You risk losing commit history if that is not the case.

Sleep function Visual Basic

This one is much easie.

Threading.Thread.Sleep(3000)

Printing all variables value from a class

From Implementing toString:

public String toString() {
  StringBuilder result = new StringBuilder();
  String newLine = System.getProperty("line.separator");

  result.append( this.getClass().getName() );
  result.append( " Object {" );
  result.append(newLine);

  //determine fields declared in this class only (no fields of superclass)
  Field[] fields = this.getClass().getDeclaredFields();

  //print field names paired with their values
  for ( Field field : fields  ) {
    result.append("  ");
    try {
      result.append( field.getName() );
      result.append(": ");
      //requires access to private field:
      result.append( field.get(this) );
    } catch ( IllegalAccessException ex ) {
      System.out.println(ex);
    }
    result.append(newLine);
  }
  result.append("}");

  return result.toString();
}

JQuery - Call the jquery button click event based on name property

You can use normal CSS selectors to select an element by name using jquery. Like this:

Button Code
<button type="button" name="mybutton">Click Me!</button>

Selector & Event Bind Code
$("button[name='mybutton']").click(function() {});

Filtering Pandas Dataframe using OR statement

You can do like below to achieve your result:

import seaborn as sns
import matplotlib.pyplot as plt
import pandas as pd
import numpy as np
....
....
#use filter with plot
#or
fg=sns.factorplot('Retailer country', data=df1[(df1['Retailer country']=='United States') | (df1['Retailer country']=='France')], kind='count')

fg.set_xlabels('Retailer country')
plt.show()


#also
#and
fg=sns.factorplot('Retailer country', data=df1[(df1['Retailer country']=='United States') & (df1['Year']=='2013')], kind='count')

fg.set_xlabels('Retailer country')
plt.show()

Find files with size in Unix

find . -size +10000k -exec ls -sd {} +

If your version of find won't accept the + notation (which acts rather like xargs does), then you might use (GNU find and xargs, so find probably supports + anyway):

find . -size +10000k -print0 | xargs -0 ls -sd

or you might replace the + with \; (and live with the relative inefficiency of this), or you might live with problems caused by spaces in names and use the portable:

find . -size +10000k -print | xargs ls -sd

The -d on the ls commands ensures that if a directory is ever found (unlikely, but...), then the directory information will be printed, not the files in the directory. And, if you're looking for files more than 1 MB (as a now-deleted comment suggested), you need to adjust the +10000k to 1000k or maybe +1024k, or +2048 (for 512-byte blocks, the default unit for -size). This will list the size and then the file name. You could avoid the need for -d by adding -type f to the find command, of course.

Winforms issue - Error creating window handle

The out of memory suggestion doesn't seem like a bad lead.

What is your program doing that it gets this error?

Is it creating a great many windows or controls? Does it create them programatically as opposed to at design time? If so, do you do this in a loop? Is that loop infinite? Are you consuming staggering boatloads of memory in some other way?

What happens when you watch the memory used by your application in task manager? Does it skyrocket to the moon? Or better yet, as suggested above use process monitor to dive into the details.

OSX -bash: composer: command not found

Well I tried a lot of things but none seemed to be working. But the following process did it right, I can now use composer command in terminal. I'm in mac OS 10.12.1

$ curl -sS https://getcomposer.org/installer | php
$ chmod +x composer.phar
$ mv composer.phar /usr/local/bin/composer
$ composer

using lodash .groupBy. how to add your own keys for grouped output?

Isn't it this simple?

var result = _(data)
            .groupBy(x => x.color)
            .map((value, key) => ({color: key, users: value}))
            .value();

How to get history on react-router v4?

If you are using redux and redux-thunk the best solution will be using react-router-redux

// then, in redux actions for example
import { push } from 'react-router-redux'

dispatch(push('/some/path'))

It's important to see the docs to do some configurations.

How to know Hive and Hadoop versions from command prompt?

This should certainly work:

hive --version

How do I select between the 1st day of the current month and current day in MySQL?

select * from table_name 
where `date` between curdate() - dayofmonth(curdate()) + 1
                 and curdate()

SQLFiddle example

How to return a PNG image from Jersey REST service method to the browser

I'm not convinced its a good idea to return image data in a REST service. It ties up your application server's memory and IO bandwidth. Much better to delegate that task to a proper web server that is optimized for this kind of transfer. You can accomplish this by sending a redirect to the image resource (as a HTTP 302 response with the URI of the image). This assumes of course that your images are arranged as web content.

Having said that, if you decide you really need to transfer image data from a web service you can do so with the following (pseudo) code:

@Path("/whatever")
@Produces("image/png")
public Response getFullImage(...) {

    BufferedImage image = ...;

    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    ImageIO.write(image, "png", baos);
    byte[] imageData = baos.toByteArray();

    // uncomment line below to send non-streamed
    // return Response.ok(imageData).build();

    // uncomment line below to send streamed
    // return Response.ok(new ByteArrayInputStream(imageData)).build();
}

Add in exception handling, etc etc.

What is dtype('O'), in pandas?

When you see dtype('O') inside dataframe this means Pandas string.

What is dtype?

Something that belongs to pandas or numpy, or both, or something else? If we examine pandas code:

df = pd.DataFrame({'float': [1.0],
                    'int': [1],
                    'datetime': [pd.Timestamp('20180310')],
                    'string': ['foo']})
print(df)
print(df['float'].dtype,df['int'].dtype,df['datetime'].dtype,df['string'].dtype)
df['string'].dtype

It will output like this:

   float  int   datetime string    
0    1.0    1 2018-03-10    foo
---
float64 int64 datetime64[ns] object
---
dtype('O')

You can interpret the last as Pandas dtype('O') or Pandas object which is Python type string, and this corresponds to Numpy string_, or unicode_ types.

Pandas dtype    Python type     NumPy type          Usage
object          str             string_, unicode_   Text

Like Don Quixote is on ass, Pandas is on Numpy and Numpy understand the underlying architecture of your system and uses the class numpy.dtype for that.

Data type object is an instance of numpy.dtype class that understand the data type more precise including:

  • Type of the data (integer, float, Python object, etc.)
  • Size of the data (how many bytes is in e.g. the integer)
  • Byte order of the data (little-endian or big-endian)
  • If the data type is structured, an aggregate of other data types, (e.g., describing an array item consisting of an integer and a float)
  • What are the names of the "fields" of the structure
  • What is the data-type of each field
  • Which part of the memory block each field takes
  • If the data type is a sub-array, what is its shape and data type

In the context of this question dtype belongs to both pands and numpy and in particular dtype('O') means we expect the string.


Here is some code for testing with explanation: If we have the dataset as dictionary

import pandas as pd
import numpy as np
from pandas import Timestamp

data={'id': {0: 1, 1: 2, 2: 3, 3: 4, 4: 5}, 'date': {0: Timestamp('2018-12-12 00:00:00'), 1: Timestamp('2018-12-12 00:00:00'), 2: Timestamp('2018-12-12 00:00:00'), 3: Timestamp('2018-12-12 00:00:00'), 4: Timestamp('2018-12-12 00:00:00')}, 'role': {0: 'Support', 1: 'Marketing', 2: 'Business Development', 3: 'Sales', 4: 'Engineering'}, 'num': {0: 123, 1: 234, 2: 345, 3: 456, 4: 567}, 'fnum': {0: 3.14, 1: 2.14, 2: -0.14, 3: 41.3, 4: 3.14}}
df = pd.DataFrame.from_dict(data) #now we have a dataframe

print(df)
print(df.dtypes)

The last lines will examine the dataframe and note the output:

   id       date                  role  num   fnum
0   1 2018-12-12               Support  123   3.14
1   2 2018-12-12             Marketing  234   2.14
2   3 2018-12-12  Business Development  345  -0.14
3   4 2018-12-12                 Sales  456  41.30
4   5 2018-12-12           Engineering  567   3.14
id               int64
date    datetime64[ns]
role            object
num              int64
fnum           float64
dtype: object

All kind of different dtypes

df.iloc[1,:] = np.nan
df.iloc[2,:] = None

But if we try to set np.nan or None this will not affect the original column dtype. The output will be like this:

print(df)
print(df.dtypes)

    id       date         role    num   fnum
0  1.0 2018-12-12      Support  123.0   3.14
1  NaN        NaT          NaN    NaN    NaN
2  NaN        NaT         None    NaN    NaN
3  4.0 2018-12-12        Sales  456.0  41.30
4  5.0 2018-12-12  Engineering  567.0   3.14
id             float64
date    datetime64[ns]
role            object
num            float64
fnum           float64
dtype: object

So np.nan or None will not change the columns dtype, unless we set the all column rows to np.nan or None. In that case column will become float64 or object respectively.

You may try also setting single rows:

df.iloc[3,:] = 0 # will convert datetime to object only
df.iloc[4,:] = '' # will convert all columns to object

And to note here, if we set string inside a non string column it will become string or object dtype.

Text-align class for inside a table

Bootstrap 2.3 has utility classes text-left, text-right, and text-center, but they do not work in table cells. Until Bootstrap 3.0 is released (where they have fixed the issue) and I am able to make the switch, I have added this to my site CSS that is loaded after bootstrap.css:

.text-right {
    text-align: right !important;
}

.text-center {
    text-align: center !important;
}

.text-left {
    text-align: left !important;
}

Content-Disposition:What are the differences between "inline" and "attachment"?

Because when I use one or another I get a window prompt asking me to download the file for both of them.

This behavior depends on the browser and the file you are trying to serve. With inline, the browser will try to open the file within the browser.

For example, if you have a PDF file and Firefox/Adobe Reader, an inline disposition will open the PDF within Firefox, whereas attachment will force it to download.

If you're serving a .ZIP file, browsers won't be able to display it inline, so for inline and attachment dispositions, the file will be downloaded.

Best way to handle list.index(might-not-exist) in python?

There is nothing "dirty" about using try-except clause. This is the pythonic way. ValueError will be raised by the .index method only, because it's the only code you have there!

To answer the comment:
In Python, easier to ask forgiveness than to get permission philosophy is well established, and no index will not raise this type of error for any other issues. Not that I can think of any.

Using :after to clear floating elements

No, you don't it's enough to do something like this:

<ul class="clearfix">
  <li>one</li>
  <li>two></li>
</ul>

And the following CSS:

ul li {float: left;}


.clearfix:after {
  content: ".";
  display: block;
  clear: both;
  visibility: hidden;
  line-height: 0;
  height: 0;
}

.clearfix {
  display: inline-block;
}

html[xmlns] .clearfix {
   display: block;
}

* html .clearfix {
   height: 1%;
}

How to build a 2 Column (Fixed - Fluid) Layout with Twitter Bootstrap?

- Another Update -

Since Twitter Bootstrap version 2.0 - which saw the removal of the .container-fluid class - it has not been possible to implement a two column fixed-fluid layout using just the bootstrap classes - however I have updated my answer to include some small CSS changes that can be made in your own CSS code that will make this possible

It is possible to implement a fixed-fluid structure using the CSS found below and slightly modified HTML code taken from the Twitter Bootstrap Scaffolding : layouts documentation page:

HTML

<div class="container-fluid fill">
    <div class="row-fluid">
        <div class="fixed">  <!-- we want this div to be fixed width -->
            ...
        </div>
        <div class="hero-unit filler">  <!-- we have removed spanX class -->
            ...
        </div>
    </div>
</div>

CSS

/* CSS for fixed-fluid layout */

.fixed {
    width: 150px;  /* the fixed width required */
    float: left;
}

.fixed + div {
     margin-left: 150px;  /* must match the fixed width in the .fixed class */
     overflow: hidden;
}


/* CSS to ensure sidebar and content are same height (optional) */

html, body {
    height: 100%;
}

.fill { 
    min-height: 100%;
    position: relative;
}

.filler:after{
    background-color:inherit;
    bottom: 0;
    content: "";
    height: auto;
    min-height: 100%;
    left: 0;
    margin:inherit;
    right: 0;
    position: absolute;
    top: 0;
    width: inherit;
    z-index: -1;  
}

I have kept the answer below - even though the edit to support 2.0 made it a fluid-fluid solution - as it explains the concepts behind making the sidebar and content the same height (a significant part of the askers question as identified in the comments)


Important

Answer below is fluid-fluid

Update As pointed out by @JasonCapriotti in the comments, the original answer to this question (created for v1.0) did not work in Bootstrap 2.0. For this reason, I have updated the answer to support Bootstrap 2.0

To ensure that the main content fills at least 100% of the screen height, we need to set the height of the html and body to 100% and create a new css class called .fill which has a minimum-height of 100%:

html, body {
    height: 100%;
}

.fill { 
    min-height: 100%;
}

We can then add the .fill class to any element that we need to take up 100% of the sceen height. In this case we add it to the first div:

<div class="container-fluid fill">
    ...
</div>

To ensure that the Sidebar and the Content columns have the same height is very difficult and unnecessary. Instead we can use the ::after pseudo selector to add a filler element that will give the illusion that the two columns have the same height:

.filler::after {
    background-color: inherit;
    bottom: 0;
    content: "";
    right: 0;
    position: absolute;
    top: 0;
    width: inherit;
    z-index: -1;  
}

To make sure that the .filler element is positioned relatively to the .fill element we need to add position: relative to .fill:

.fill { 
    min-height: 100%;
    position: relative;
}

And finally add the .filler style to the HTML:

HTML

<div class="container-fluid fill">
    <div class="row-fluid">
        <div class="span3">
            ...
        </div>
        <div class="span9 hero-unit filler">
            ...
        </div>
    </div>
</div>

Notes

  • If you need the element on the left of the page to be the filler then you need to change right: 0 to left: 0.

How to take backup of a single table in a MySQL database?

just use mysqldump -u root database table or if using with password mysqldump -u root -p pass database table

INSERT IF NOT EXISTS ELSE UPDATE?

Upsert is what you want. UPSERT syntax was added to SQLite with version 3.24.0 (2018-06-04).

CREATE TABLE phonebook2(
  name TEXT PRIMARY KEY,
  phonenumber TEXT,
  validDate DATE
);

INSERT INTO phonebook2(name,phonenumber,validDate)
  VALUES('Alice','704-555-1212','2018-05-08')
  ON CONFLICT(name) DO UPDATE SET
    phonenumber=excluded.phonenumber,
    validDate=excluded.validDate
  WHERE excluded.validDate>phonebook2.validDate;

Be warned that at this point the actual word "UPSERT" is not part of the upsert syntax.

The correct syntax is

INSERT INTO ... ON CONFLICT(...) DO UPDATE SET...

and if you are doing INSERT INTO SELECT ... your select needs at least WHERE true to solve parser ambiguity about the token ON with the join syntax.

Be warned that INSERT OR REPLACE... will delete the record before inserting a new one if it has to replace, which could be bad if you have foreign key cascades or other delete triggers.

How do I change the select box arrow

CSS

select.inpSelect {
  //Remove original arrows
  -webkit-appearance: none; 
  //Use png at assets/selectArrow.png for the arrow on the right
  //Set the background color to a BadAss Green color 
  background: url(assets/selectArrow.png) no-repeat right #BADA55;
}

How to use new PasswordEncoder from Spring Security

I had a similar issue. I needed to keep the legacy encrypted passwords (Base64/SHA-1/Random salt Encoded) as users will not want to change their passwords or re-register. However I wanted to use the BCrypt encoder moving forward too.

My solution was to write a bespoke decoder that checks to see which encryption method was used first before matching (BCrypted ones start with $).

To get around the salt issue, I pass into the decoder a concatenated String of salt + encrypted password via my modified user object.

Decoder

@Component
public class LegacyEncoder implements PasswordEncoder {

    private static final String BCRYP_TYPE = "$";
    private static final PasswordEncoder BCRYPT = new BCryptPasswordEncoder();

    @Override
    public String encode(CharSequence rawPassword) {

    return BCRYPT.encode(rawPassword);
    }

    @Override
    public boolean matches(CharSequence rawPassword, String encodedPassword) {

    if (encodedPassword.startsWith(BCRYP_TYPE)) {
        return BCRYPT.matches(rawPassword, encodedPassword);
    }

    return sha1SaltMatch(rawPassword, encodedPassword);
    }

    @SneakyThrows
    private boolean sha1SaltMatch(CharSequence rawPassword, String encodedPassword) {

    String[] saltHash = encodedPassword.split(User.SPLIT_CHAR);

    // Legacy code from old system   
    byte[] b64salt = Base64.getDecoder().decode(saltHash[0].getBytes());
    byte[] validHash = Base64.getDecoder().decode(saltHash[1]);
    byte[] checkHash = Utility.getHash(5, rawPassword.toString(), b64salt);

    return Arrays.equals(checkHash, validHash);
    }

}

User Object

public class User implements UserDetails {

    public static final String SPLIT_CHAR = ":";

    @Id
    @Column(name = "user_id", nullable = false)
    private Integer userId;

    @Column(nullable = false, length = 60)
    private String password;

    @Column(nullable = true, length = 32)
    private String salt;

.
.

    @PostLoad
    private void init() {

    username = emailAddress; //To comply with UserDetails
    password = salt == null ? password : salt + SPLIT_CHAR + password;
    }        

You can also add a hook to re-encode the password in the new BCrypt format and replace it. Thus phasing out the old method.

Append Char To String in C?

here's it, it WORKS 100%

char* appending(char *cArr, const char c)

{

int len = strlen(cArr);

cArr[len + 1] = cArr[len];

cArr[len] = c;

return cArr;


}

How to uninstall a package installed with pip install --user

example to uninstall package 'oauth2client' on MacOS:

pip uninstall oauth2client

Multiple axis line chart in excel

Best and Free ( maybe only) solution for this is google sheets. i don't know whether it plots as u expected or not but certainly you can draw multiple axes.

Regards

keerthan

How do you use "git --bare init" repository?

Based on Mark Longair & Roboprog answers :

if git version >= 1.8

git init --bare --shared=group .git
git config receive.denyCurrentBranch ignore

Or :

if git version < 1.8

mkdir .git
cd .git
git init --bare --shared=group 
git config receive.denyCurrentBranch ignore

Simulating Slow Internet Connection

You can try Dummynet, it can simulates queue and bandwidth limitations, delays, packet losses, and multipath effects

How do I get the current absolute URL in Ruby on Rails?

None of the suggestions here in the thread helped me sadly, except the one where someone said he used the debugger to find what he looked for.

I've created some custom error pages instead of the standard 404 and 500, but request.url ended in /404 instead of the expected /non-existing-mumbo-jumbo.

What I needed to use was

request.original_url

How to randomly select an item from a list?

foo = ['a', 'b', 'c', 'd', 'e']
number_of_samples = 1

In python 2:

random_items = random.sample(population=foo, k=number_of_samples)

In python 3:

random_items = random.choices(population=foo, k=number_of_samples)

PHP DOMDocument loadHTML not encoding UTF-8 correctly

Make sure the real source file is saved as UTF-8 (You may even want to try the non-recommended BOM Chars with UTF-8 to make sure).

Also in case of HTML, make sure you have declared the correct encoding using meta tags:

<meta http-equiv="Content-Type" content="text/html; charset=utf-8">

If it's a CMS (as you've tagged your question with Joomla) you may need to configure appropriate settings for the encoding.

How to return a dictionary | Python

I followed approach as shown in code below to return a dictionary. Created a class and declared dictionary as global and created a function to add value corresponding to some keys in dictionary.

**Note have used Python 2.7 so some minor modification might be required for Python 3+

class a:
    global d
    d={}
    def get_config(self,x):
        if x=='GENESYS':
            d['host'] = 'host name'
            d['port'] = '15222'
        return d

Calling get_config method using class instance in a separate python file:

from constant import a
class b:
    a().get_config('GENESYS')
    print a().get_config('GENESYS').get('host')
    print a().get_config('GENESYS').get('port')

Find UNC path of a network drive?

This question has been answered already, but since there is a more convenient way to get the UNC path and some more I recommend using Path Copy, which is free and you can practically get any path you want with one click:

https://pathcopycopy.github.io/

Here is a screenshot demonstrating how it works. The latest version has more options and definitely UNC Path too:

enter image description here

Why I'm getting 'Non-static method should not be called statically' when invoking a method in a Eloquent model?

You defined your method as non-static and you are trying to invoke it as static. That said...

1.if you want to invoke a static method, you should use the :: and define your method as static.

// Defining a static method in a Foo class.
public static function getAll() { /* code */ }

// Invoking that static method
Foo::getAll();

2.otherwise, if you want to invoke an instance method you should instance your class, use ->.

// Defining a non-static method in a Foo class.
public function getAll() { /* code */ }

// Invoking that non-static method.
$foo = new Foo();
$foo->getAll();

Note: In Laravel, almost all Eloquent methods return an instance of your model, allowing you to chain methods as shown below:

$foos = Foo::all()->take(10)->get();

In that code we are statically calling the all method via Facade. After that, all other methods are being called as instance methods.

Could not load file or assembly ... An attempt was made to load a program with an incorrect format (System.BadImageFormatException)

I have detected something different from the other answers. Reaching this exception in my project was the result of a corrupt compilation. Without making any changes, just forcing rebuild, it was fixed.

How do I resolve this "ORA-01109: database not open" error?

If your database is down then during login as SYSDBA you can assume this. While login command will be executed like sqlplus sys/sys_password as sysdba that time you will get "connected to idle instance" reply from database. This message indicates your database is down. You should need to check first alert.log file about why database is down. If you found it was downed normally then you can issue "startup" command for starting database and after that execute your create user command. If you found database is having issue like missing datafile or something else then you need to recover database first and open database for executing your create user command.

"alter database open" command only accepted by database while it is on Mount stage. If database is down then it won't accept "alter database open" command.

Why is there no xrange function in Python3?

Python3's range is Python2's xrange. There's no need to wrap an iter around it. To get an actual list in Python3, you need to use list(range(...))

If you want something that works with Python2 and Python3, try this

try:
    xrange
except NameError:
    xrange = range

SQL Server table creation date query

For 2005 up, you can use

SELECT
        [name]
       ,create_date
       ,modify_date
FROM
        sys.tables

I think for 2000, you need to have enabled auditing.

Difference between thread's context class loader and normal classloader

This does not answer the original question, but as the question is highly ranked and linked for any ContextClassLoader query, I think it is important to answer the related question of when the context class loader should be used. Short answer: never use the context class loader! But set it to getClass().getClassLoader() when you have to call a method that is missing a ClassLoader parameter.

When code from one class asks to load another class, the correct class loader to use is the same class loader as the caller class (i.e., getClass().getClassLoader()). This is the way things work 99.9% of the time because this is what the JVM does itself the first time you construct an instance of a new class, invoke a static method, or access a static field.

When you want to create a class using reflection (such as when deserializing or loading a configurable named class), the library that does the reflection should always ask the application which class loader to use, by receiving the ClassLoader as a parameter from the application. The application (which knows all the classes that need constructing) should pass it getClass().getClassLoader().

Any other way to obtain a class loader is incorrect. If a library uses hacks such as Thread.getContextClassLoader(), sun.misc.VM.latestUserDefinedLoader(), or sun.reflect.Reflection.getCallerClass() it is a bug caused by a deficiency in the API. Basically, Thread.getContextClassLoader() exists only because whoever designed the ObjectInputStream API forgot to accept the ClassLoader as a parameter, and this mistake has haunted the Java community to this day.

That said, many many JDK classes use one of a few hacks to guess some class loader to use. Some use the ContextClassLoader (which fails when you run different apps on a shared thread pool, or when you leave the ContextClassLoader null), some walk the stack (which fails when the direct caller of the class is itself a library), some use the system class loader (which is fine, as long as it is documented to only use classes in the CLASSPATH) or bootstrap class loader, and some use an unpredictable combination of the above techniques (which only makes things more confusing). This has resulted in much weeping and gnashing of teeth.

When using such an API, first, try to find an overload of the method that accepts the class loader as a parameter. If there is no sensible method, then try setting the ContextClassLoader before the API call (and resetting it afterwards):

ClassLoader originalClassLoader = Thread.currentThread().getContextClassLoader();
try {
    Thread.currentThread().setContextClassLoader(getClass().getClassLoader());
    // call some API that uses reflection without taking ClassLoader param
} finally {
    Thread.currentThread().setContextClassLoader(originalClassLoader);
}

PHP Warning: Module already loaded in Unknown on line 0

Run php --ini and notice file path on Loaded Configuration File.
Then run command like cat -n /etc/php/7.2/cli/php.ini | grep intl to find if the extension is commented or not.
Then update loaded configuration file by commenting line by adding ; such as ;extension=intl

This can happen when you install php-intl package and also enable the same extension on php.ini file.

DBMS_OUTPUT.PUT_LINE not printing

For SQL Developer

You have to execute it manually

SET SERVEROUTPUT ON 

After that if you execute any procedure with DBMS_OUTPUT.PUT_LINE('info'); or directly .

This will print the line

And please don't try to add this

 SET SERVEROUTPUT ON

inside the definition of function and procedure, it will not compile and will not work.

Convert string to date in bash

We can use date -d option

1) Change format to "%Y-%m-%d" format i.e 20121212 to 2012-12-12

date -d '20121212' +'%Y-%m-%d'

2)Get next or last day from a given date=20121212. Like get a date 7 days in past with specific format

date -d '20121212 -7 days' +'%Y-%m-%d'

3) If we are getting date in some variable say dat

dat2=$(date -d "$dat -1 days" +'%Y%m%d')

App crashing when trying to use RecyclerView on android 5.0

If I where you I will do this. onView(withId(android.R.id.list)).perform(RecyclerViewActions.scrollToPosition(3)); android.R.id.list change it to your list id and position will be your position inside your array.

A JSONObject text must begin with '{' at 1 [character 2 line 1] with '{' error

Your JSON is perfectly valid. Try using these JSON classes to parse it. http://json.org/java/

Java reverse an int value without using array

public static void reverse(int number) {
    while (number != 0) {
        int remainder = number % 10;
        System.out.print(remainder);
        number = number / 10;
    }

    System.out.println();
}

What this does is, strip the last digit (within the 10s place) and add it to the front and then divides the number by 10, removing the last digit.

In jQuery how can I set "top,left" properties of an element with position values relative to the parent and not the document?

To set the position relative to the parent you need to set the position:relative of parent and position:absolute of the element

$("#mydiv").parent().css({position: 'relative'});
$("#mydiv").css({top: 200, left: 200, position:'absolute'});

This works because position: absolute; positions relatively to the closest positioned parent (i.e., the closest parent with any position property other than the default static).

Convert PDF to clean SVG?

You can use Inkscape on the commandline only, without opening a GUI. Try this:

inkscape \
  --without-gui \
  --file=input.pdf \
  --export-plain-svg=output.svg 

For a complete list of all commandline options, run inkscape --help.

How to get MD5 sum of a string using python?

You can use b character in front of a string literal:

import hashlib
print(hashlib.md5(b"Hello MD5").hexdigest())
print(hashlib.md5("Hello MD5".encode('utf-8')).hexdigest())

Out:

e5dadf6524624f79c3127e247f04b548
e5dadf6524624f79c3127e247f04b548

What is the difference between a definition and a declaration?

From the C++ standard section 3.1:

A declaration introduces names into a translation unit or redeclares names introduced by previous declarations. A declaration specifies the interpretation and attributes of these names.

The next paragraph states (emphasis mine) that a declaration is a definition unless...

... it declares a function without specifying the function’s body:

void sqrt(double);  // declares sqrt

... it declares a static member within a class definition:

struct X
{
    int a;         // defines a
    static int b;  // declares b
};

... it declares a class name:

class Y;

... it contains the extern keyword without an initializer or function body:

extern const int i = 0;  // defines i
extern int j;  // declares j
extern "C"
{
    void foo();  // declares foo
}

... or is a typedef or using statement.

typedef long LONG_32;  // declares LONG_32
using namespace std;   // declares std

Now for the big reason why it's important to understand the difference between a declaration and definition: the One Definition Rule. From section 3.2.1 of the C++ standard:

No translation unit shall contain more than one definition of any variable, function, class type, enumeration type, or template.

How to calculate time elapsed in bash script?

% start=$(date +%s)
% echo "Diff: $(date -d @$(($(date +%s)-$start)) +"%M minutes %S seconds")"
Diff: 00 minutes 11 seconds

Suppress console output in PowerShell

It is a duplicate of this question, with an answer that contains a time measurement of the different methods.

Conclusion: Use [void] or > $null.

CSS Margin: 0 is not setting to 0

Try...

body {
   margin: 0;
   padding: 0;
}

jsFiddle.

Because of browsers using different default stylesheets, some people recommend a reset stylesheet such as Eric Meyer's Reset Reloaded.

Flutter Countdown Timer

Little late to the party but why don't you guys try animation.No I am not telling you to manage animation controllers and disposing them off and all that stuff.theres a built-in widget for that called TweenAnimationBuilder.You can animate between values of any type,heres an example with a Duration class

TweenAnimationBuilder<Duration>(
              duration: Duration(minutes: 3),
              tween: Tween(begin: Duration(minutes: 3), end: Duration.zero),
              onEnd: () {
                print('Timer ended');
              },
              builder: (BuildContext context, Duration value, Widget child) {
              final minutes = value.inMinutes;
              final seconds = value.inSeconds % 60;
              return Padding(
                     padding: const EdgeInsets.symmetric(vertical: 5),
                     child: Text('$minutes:$seconds',
                            textAlign: TextAlign.center,
                            style: TextStyle(
                            color: Colors.black,
                            fontWeight: FontWeight.bold,
                            fontSize: 30)));
              }),

and You also get onEnd call back which notifies you when the animation completes;

here's the output

Rotate axis text in python matplotlib

I came up with a similar example. Again, the rotation keyword is.. well, it's key.

from pylab import *
fig = figure()
ax = fig.add_subplot(111)
ax.bar( [0,1,2], [1,3,5] )
ax.set_xticks( [ 0.5, 1.5, 2.5 ] )
ax.set_xticklabels( ['tom','dick','harry'], rotation=45 ) ;

AWK to print field $2 first, then field $1

Maybe your file contains CRLF terminator. Every lines followed by \r\n.

awk recognizes the $2 actually $2\r. The \r means goto the start of the line.

{print $2\r$1} will print $2 first, then return to the head, then print $1. So the field 2 is overlaid by the field 1.

Copy multiple files with Ansible

copy module is a wrong tool for copying many files and/or directory structure, use synchronize module instead which uses rsync as backend. Mind you, it requires rsync installed on both controller and target host. It's really powerful, check ansible documentation.

Example - copy files from build directory (with subdirectories) of controller to /var/www/html directory on target host:

synchronize:
  src: ./my-static-web-page/build/
  dest: /var/www/html
  rsync_opts:
    - "--chmod=D2755,F644" # copy from windows - force permissions

How to fix java.net.SocketException: Broken pipe?

JavaDoc:

The maximum queue length for incoming connection indications (a request to connect) is set to 50. If a connection indication arrives when the queue is full, the connection is refused.

You should increase "backlog" parameter of your ServerSocket, for example

int backlogSize = 50 ;
new ServerSocket(port, backlogSize);

Why the switch statement cannot be applied on strings?

To add a variation using the simplest container possible (no need for an ordered map)... I wouldn't bother with an enum--just put the container definition immediately before the switch so it'll be easy to see which number represents which case.

This does a hashed lookup in the unordered_map and uses the associated int to drive the switch statement. Should be quite fast. Note that at is used instead of [], as I've made that container const. Using [] can be dangerous--if the string isn't in the map, you'll create a new mapping and may end up with undefined results or a continuously growing map.

Note that the at() function will throw an exception if the string isn't in the map. So you may want to test first using count().

const static std::unordered_map<std::string,int> string_to_case{
   {"raj",1},
   {"ben",2}
};
switch(string_to_case.at("raj")) {
  case 1: // this is the "raj" case
       break;
  case 2: // this is the "ben" case
       break;


}

The version with a test for an undefined string follows:

const static std::unordered_map<std::string,int> string_to_case{
   {"raj",1},
   {"ben",2}
};
// in C++20, you can replace .count with .contains
switch(string_to_case.count("raj") ? string_to_case.at("raj") : 0) {
  case 1: // this is the "raj" case
       break;
  case 2: // this is the "ben" case
       break;
  case 0: //this is for the undefined case

}

How to read user input into a variable in Bash?

Use read -p:

# fullname="USER INPUT"
read -p "Enter fullname: " fullname
# user="USER INPUT"
read -p "Enter user: " user

If you like to confirm:

read -p "Continue? (Y/N): " confirm && [[ $confirm == [yY] || $confirm == [yY][eE][sS] ]] || exit 1

You should also quote your variables to prevent pathname expansion and word splitting with spaces:

# passwd "$user"
# mkdir "$home"
# chown "$user:$group" "$home"

Java: Convert String to TimeStamp

DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");

Date date = formatter.parse(dateString);

Timestamp timestamp = new Timestamp(date.getTime());

System.out.println(timestamp);

Add space between HTML elements only using CSS

add these rules to the parent container:

display: grid
grid-auto-flow: column
grid-column-gap: 10px

Good reference: https://cssreference.io/

Browser compatibility: https://gridbyexample.com/browsers/

How to delete Tkinter widgets from a window?

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

from tkinter import *

root = Tk()

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

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

root.mainloop()

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

Validate phone number using javascript

You can use this jquery plugin:

http://digitalbush.com/projects/masked-input-plugin/

Refer to demo tab, phone option.

How to decode encrypted wordpress admin password?

MD5 encrypting is possible, but decrypting is still unknown (to me). However, there are many ways to compare these things.

  1. Using compare methods like so:

    <?php
      $db_pass = $P$BX5675uhhghfhgfhfhfgftut/0;
      $my_pass = "mypass";
      if ($db_pass === md5($my_pass)) {
        // password is matched
      } else {
        // password didn't match
      }
    
  2. Only for WordPress users. If you have access to your PHPMyAdmin, focus you have because you paste that hashing here: $P$BX5675uhhghfhgfhfhfgftut/0, WordPress user_pass is not only MD5 format it also uses utf8_mb4_cli charset so what to do?

    That's why I use another Approach if I forget my WordPress password I use

    I install other WordPress with new password :P, and I then go to PHPMyAdmin and copy that hashing from the database and paste that hashing to my current PHPMyAdmin password ( which I forget )

    EASY is use this :

    1. password = "ARJUNsingh@123"
    2. password_hasing = " $P$BDSdKx2nglM.5UErwjQGeVtVWvjEvD1 "
    3. Replace your $P$BX5675uhhghfhgfhfhfgftut/0 with my $P$BDSdKx2nglM.5UErwjQGeVtVWvjEvD1

I USE THIS APPROACH FOR MY SELF WHEN I DESIGN THEMES AND PLUGINS

WORDPRESS USE THIS

https://developer.wordpress.org/reference/functions/wp_hash_password/

jQuery override default validation error message display (Css) Popup/Tooltip like

A few things:

First, I don't think you really need a validation error for a radio fieldset because you could just have one of the fields checked by default. Most people would rather correct something then provide something. For instance:

   Age: (*) 12 - 18 | () 19 - 30 | 31 - 50 

is more likely to be changed to the right answer as the person DOESN'T want it to go to the default. If they see it blank, they are more likely to think "none of your business" and skip it.

Second, I was able to get the effect I think you are wanting without any positioning properties. You just add padding-right to the form (or the div of the form, whatever) to provide enough room for your error and make sure your error will fit in that area. Then, you have a pre-set up css class called "error" and you set it as having a negative margin-top roughly the height of your input field and a margin-left about the distance from the left to where your padding-right should start. I tried this out, it's not great, but it works with three properties and requires no floats or absolutes:

   <style type="text/css">
    .error {
        width: 13em; /* Ensures that the div won't exceed right padding of form */
        margin-top: -1.5em;  /*Moves the div up to the same level as input */
        margin-left: 11em;   /*Moves div to the right */
        font-size: .9em;     /*Makes sure that the error div is smaller than input */
    }

   <form>
   <label for="name">Name:</label><input id="name" type="textbox" />
   <div class="error"><<< This field is required!</div>
   <label for="numb">Phone:</label><input id="numb" type="textbox" />
   <div class="error"><<< This field is required!</div>
   </form>

Update rows in one table with data from another table based on one column in each being equal

If you want to update matching rows in t1 with data from t2 then:

update t1
set (c1, c2, c3) = 
(select c1, c2, c3 from t2
 where t2.user_id = t1.user_id)
where exists
(select * from t2
 where t2.user_id = t1.user_id)

The "where exists" part it to prevent updating the t1 columns to null where no match exists.

Python: converting a list of dictionaries to json

import json

list = [{'id': 123, 'data': 'qwerty', 'indices': [1,10]}, {'id': 345, 'data': 'mnbvc', 'indices': [2,11]}]

Write to json File:

with open('/home/ubuntu/test.json', 'w') as fout:
    json.dump(list , fout)

Read Json file:

with open(r"/home/ubuntu/test.json", "r") as read_file:
    data = json.load(read_file)
print(data)
#list = [{'id': 123, 'data': 'qwerty', 'indices': [1,10]}, {'id': 345, 'data': 'mnbvc', 'indices': [2,11]}]

error "Could not get BatchedBridge, make sure your bundle is packaged properly" on start of app

Try this command in terminal and then reload. It worked for me

adb reverse tcp:8081 tcp:8081

The service cannot be started, either because it is disabled or because it has no enabled devices associated with it

Oddly enough, the issue for me was I was trying to open 2012 SQL Server Integration Services on SSMS 2008 R2. When I opened the same in SSMS 2012, it connected right away.

Create JPA EntityManager without persistence.xml configuration file

DataNucleus JPA that I use also has a way of doing this in its docs. No need for Spring, or ugly implementation of PersistenceUnitInfo.

Simply do as follows

import org.datanucleus.metadata.PersistenceUnitMetaData;
import org.datanucleus.api.jpa.JPAEntityManagerFactory;

PersistenceUnitMetaData pumd = new PersistenceUnitMetaData("dynamic-unit", "RESOURCE_LOCAL", null);
pumd.addClassName("mydomain.test.A");
pumd.setExcludeUnlistedClasses();
pumd.addProperty("javax.persistence.jdbc.url", "jdbc:h2:mem:nucleus");
pumd.addProperty("javax.persistence.jdbc.user", "sa");
pumd.addProperty("javax.persistence.jdbc.password", "");
pumd.addProperty("datanucleus.schema.autoCreateAll", "true");

EntityManagerFactory emf = new JPAEntityManagerFactory(pumd, null);

How can I divide one column of a data frame through another?

Hadley Wickham

dplyr

packages is always a saver in case of data wrangling. To add the desired division as a third variable I would use mutate()

d <- mutate(d, new = min / count2.freq)

How can I introduce multiple conditions in LIKE operator?

If your parameter value is not fixed or your value can be null based on business you can try the following approach.

DECLARE @DrugClassstring VARCHAR(MAX);
SET @DrugClassstring = 'C3,C2'; -- You can pass null also

---------------------------------------------

IF @DrugClassstring IS NULL 
    SET @DrugClassstring = 'C3,C2,C4,C5,RX,OT'; -- If null you can set your all conditional case that will return for all
SELECT dn.drugclass_FK , dn.cdrugname
FROM drugname AS dn
INNER JOIN dbo.SplitString(@DrugClassstring, ',') class ON dn.drugclass_FK = class.[Name] -- SplitString is a a function

SplitString function

SET ANSI_NULLS ON;
GO
SET QUOTED_IDENTIFIER ON;
GO
ALTER FUNCTION [dbo].[SplitString](@stringToSplit VARCHAR(MAX),
                                   @delimeter     CHAR(1)      = ',')
RETURNS @returnList TABLE([Name] [NVARCHAR](500))
AS
     BEGIN

         --It's use in report sql, before any change concern to everyone

         DECLARE @name NVARCHAR(255);
         DECLARE @pos INT;
         WHILE CHARINDEX(@delimeter, @stringToSplit) > 0
             BEGIN
                 SELECT @pos = CHARINDEX(@delimeter, @stringToSplit);
                 SELECT @name = SUBSTRING(@stringToSplit, 1, @pos-1);
                 INSERT INTO @returnList
                        SELECT @name;
                 SELECT @stringToSplit = SUBSTRING(@stringToSplit, @pos+1, LEN(@stringToSplit)-@pos);
             END;
         INSERT INTO @returnList
                SELECT @stringToSplit;
         RETURN;
     END;

How do I determine the current operating system with Node.js

This Works fine for me

var osvar = process.platform;

if (osvar == 'darwin') {
    console.log("you are on a mac os");
}else if(osvar == 'win32'){
    console.log("you are on a windows os")
}else{
    console.log("unknown os")
}

Getting HTML elements by their attribute names

You can get attribute using javascript,

element.getAttribute(attributeName);

Ex:

var wrap = document.getElementById("wrap");
var myattr = wrap.getAttribute("title");

Refer:

https://developer.mozilla.org/en/DOM/element.getAttribute

How do I activate a virtualenv inside PyCharm's terminal?

Thanks Chris, your script worked for some projects but not all on my machine. Here is a script that I wrote and I hope anyone finds it useful.

#Stored in ~/.pycharmrc 

ACTIVATERC=$(python -c 'import re
import os
from glob import glob

try:
  #sets Current Working Directory to _the_projects .idea folder
  os.chdir(os.getcwd()+"/.idea") 

  #gets every file in the cwd and sets _the_projects iml file
  for file in glob("*"): 
    if re.match("(.*).iml", file):
      project_iml_file = file

  #gets _the_virtual_env for _the_project
  for line in open(project_iml_file):
    env_name = re.findall("~/(.*)\" jdkType", line.strip())
    # created or changed a virtual_env after project creation? this will be true
    if env_name:
      print env_name[0] + "/bin/activate"
      break

    inherited = re.findall("type=\"inheritedJdk\"", line.strip())
    # set a virtual_env during project creation? this will be true
    if inherited:
      break

  # find _the_virtual_env in misc.xml
  if inherited:
    for line in open("misc.xml").readlines():
      env_at_project_creation = re.findall("\~/(.*)\" project-jdk", line.strip())
      if env_at_project_creation:
        print env_at_project_creation[0] + "/bin/activate"
        break
finally:
  pass
')

if [ "$ACTIVATERC" ] ; then . "$HOME/$ACTIVATERC" ; fi

How to do multiple conditions for single If statement

Use the 'And' keyword for a logical and. Like this:

If Not ((filename = testFileName) And (fileName <> "")) Then

Pushing from local repository to GitHub hosted remote

open the command prompt Go to project directory

type git remote add origin your git hub repository location with.git

c# - approach for saving user settings in a WPF application?

Apart from a database, you can also have following options to save user related settings

  1. registry under HKEY_CURRENT_USER

  2. in a file in AppData folder

  3. using Settings file in WPF and by setting its scope as User

Displaying tooltip on mouse hover of a text

For the sake of ease of use and understandability.

You can simply put a Tooltip anywhere on your form (from toolbox). You will then be given an options in the Properties of everything else in your form to determine what is displayed in that Tooltip (it reads something like "ToolTip on toolTip1"). Anytime you hover on an object, the text in that property will be displayed as a tooltip.

This does not cover custom on-the-fly tooltips like the original question is asking for. But I am leaving this here for others that do not need

How to create EditText accepts Alphabets only in android?

EditText state = (EditText) findViewById(R.id.txtState);


                Pattern ps = Pattern.compile("^[a-zA-Z ]+$");
                Matcher ms = ps.matcher(state.getText().toString());
                boolean bs = ms.matches();
                if (bs == false) {
                    if (ErrorMessage.contains("invalid"))
                        ErrorMessage = ErrorMessage + "state,";
                    else
                        ErrorMessage = ErrorMessage + "invalid state,";

                }

What is the difference between ManualResetEvent and AutoResetEvent in .NET?

autoResetEvent.WaitOne()

is similar to

try
{
   manualResetEvent.WaitOne();
}
finally
{
   manualResetEvent.Reset();
}

as an atomic operation

VBA - Select columns using numbers?

I was looking for a similar thing. My problem was to find the last column based on row 5 and then select 3 columns before including the last column.

Dim lColumn As Long

lColumn = ActiveSheet.Cells(5,Columns.Count).End(xlToLeft).Column
MsgBox ("The last used column is: " & lColumn)
Range(Columns(lColumn - 3), Columns(lColumn)).Select

Message box is optional as it is more of a control check. If you want to select the columns after the last column then you simply reverse the range selection

Dim lColumn As Long

lColumn = ActiveSheet.Cells(5,Columns.Count).End(xlToLeft).Column
MsgBox ("The last used column is: " & lColumn)
Range(Columns(lColumn), Columns(lColumn + 3)).Select

ionic build Android | error: No installed build tools found. Please install the Android build tools

2018

The "android" command is deprecated.

try

sdkmanager "build-tools;27.0.3"

This work for me, as #Fadhil said

List rows after specific date

Simply put:

SELECT * 
FROM TABLE_NAME
WHERE
dob > '1/21/2012'

Where 1/21/2012 is the date and you want all data, including that date.

SELECT * 
FROM TABLE_NAME
WHERE
dob BETWEEN '1/21/2012' AND '2/22/2012'

Use a between if you're selecting time between two dates

How to get the file-path of the currently executing javascript code

Refining upon the answers found here:

little trick

getCurrentScript and getCurrentScriptPath

I came up with the following:

//Thanks to https://stackoverflow.com/a/27369985/5175935
var getCurrentScript = function () {

    if ( document.currentScript && ( document.currentScript.src !== '' ) )
        return document.currentScript.src;
    var scripts = document.getElementsByTagName( 'script' ),
        str = scripts[scripts.length - 1].src;
    if ( str !== '' )
        return src;
    //Thanks to https://stackoverflow.com/a/42594856/5175935
    return new Error().stack.match(/(https?:[^:]*)/)[0];

};

//Thanks to https://stackoverflow.com/a/27369985/5175935
var getCurrentScriptPath = function () {
    var script = getCurrentScript(),
        path = script.substring( 0, script.lastIndexOf( '/' ) );
    return path;
};

List Git commits not pushed to the origin yet

git log origin/master..master

or, more generally:

git log <since>..<until>

You can use this with grep to check for a specific, known commit:

git log <since>..<until> | grep <commit-hash>

Or you can also use git-rev-list to search for a specific commit:

git rev-list origin/master | grep <commit-hash>

Let JSON object accept bytes or let urlopen output strings

HTTP sends bytes. If the resource in question is text, the character encoding is normally specified, either by the Content-Type HTTP header or by another mechanism (an RFC, HTML meta http-equiv,...).

urllib should know how to encode the bytes to a string, but it's too naïve—it's a horribly underpowered and un-Pythonic library.

Dive Into Python 3 provides an overview about the situation.

Your "work-around" is fine—although it feels wrong, it's the correct way to do it.

Error: vector does not name a type

You forgot to add std:: namespace prefix to vector class name.

Allowed memory size of 262144 bytes exhausted (tried to allocate 24576 bytes)

I see my problem is a little bit different from yours, but I'll post this answer in case it helps someone else. I was using MB as shorthand instead of M when defining my memory_limit, and php was silently ignoring it. I changed it to an integer (in bytes) and the problem was solved.

My php.ini changed as follows: memory_limit = 512MB to memory_limit = 536870912. This fixed my problem. Hope it helps with someone else's! You can read up on php's shorthand here.

Good luck!

Edit

As Yaodong points out, you can just as easily use the correct shorthand, "M", instead of using byte values. I changed mine to byte values for debugging purposes and then didn't bother to change it back.

Sync data between Android App and webserver

If you write this yourself these are some of the points to keep in mind

Proper authentication between the device and the Sync Server

A sync protocol between the device and the server. It will usually go in 3 phases, authentication, data exchange, status exchange (which operations worked and which failed)

Pick your payload format. I suggest SyncML based XML mixed with JSON based format to represent the actual data. So SyncML for the protocol, and JSON for the actual data being exchanged. Using JSON Array while manipulating the data is always preferred as it is easy to access data using JSON Array.

Keeping track of data changes on both client and server. You can maintain a changelog of ids that change and pick them up during a sync session. Also, clear the changelog as the objects are successfully synchronized. You can also use a boolean variable to confirm the synchronization status, i.e. last time of sync. It will be helpful for end users to identify the time when last sync is done.

Need to have a way to communicate from the server to the device to start a sync session as data changes on the server. You can use C2DM or write your own persistent tcp based communication. The tcp approach is a lot seamless

A way to replicate data changes across multiple devices

And last but not the least, a way to detect and handle conflicts

Hope this helps as a good starting point.

django MultiValueDictKeyError error, how do I deal with it

Choose what is best for you:

1

is_private = request.POST.get('is_private', False);

If is_private key is present in request.POST the is_private variable will be equal to it, if not, then it will be equal to False.

2

if 'is_private' in request.POST:
    is_private = request.POST['is_private']
else:
    is_private = False

3

from django.utils.datastructures import MultiValueDictKeyError
try:
    is_private = request.POST['is_private']
except MultiValueDictKeyError:
    is_private = False

Strip out HTML and Special Characters

You can do it in one single line :) specially useful for GET or POST requests

$clear = preg_replace('/[^A-Za-z0-9\-]/', '', urldecode($_GET['id']));

How do you view ALL text from an ntext or nvarchar(max) in SSMS?

Options (Query Results/SQL Server/Results to Grid Page)

To change the options for the current queries, click Query Options on the Query menu, or right-click in the SQL Server Query window and select Query Options.

...

Maximum Characters Retrieved
Enter a number from 1 through 65535 to specify the maximum number of characters that will be displayed in each cell.

Maximum is, as you see, 64k. The default is much smaller.

BTW Results to Text has even more drastic limitation:

Maximum number of characters displayed in each column
This value defaults to 256. Increase this value to display larger result sets without truncation. The maximum value is 8,192.

Python Dictionary contains List as Value - How to update?

An accessed dictionary value (a list in this case) is the original value, separate from the dictionary which is used to access it. You would increment the values in the list the same way whether it's in a dictionary or not:

l = dictionary.get('C1')
for i in range(len(l)):
    l[i] += 10

What does "Use of unassigned local variable" mean?

Because if none of the if statements evaluate to true then the local variable will be unassigned. Throw an else statement in there and assign some values to those variables in case the if statements don't evaluate to true. Post back here if that doesn't make the error go away.

Your other option is to initialize the variables to some default value when you declare them at the beginning of your code.

Set variable with multiple values and use IN

Ideally you shouldn't be splitting strings in T-SQL at all.

Barring that change, on older versions before SQL Server 2016, create a split function:

CREATE FUNCTION dbo.SplitStrings
(
    @List      nvarchar(max), 
    @Delimiter nvarchar(2)
)
RETURNS TABLE
WITH SCHEMABINDING
AS
  RETURN ( WITH x(x) AS
    (
      SELECT CONVERT(xml, N'<root><i>' 
        + REPLACE(@List, @Delimiter, N'</i><i>') 
        + N'</i></root>')
    )
    SELECT Item = LTRIM(RTRIM(i.i.value(N'.',N'nvarchar(max)')))
      FROM x CROSS APPLY x.nodes(N'//root/i') AS i(i)
  );
GO

Now you can say:

DECLARE @Values varchar(1000);

SET @Values = 'A, B, C';

SELECT blah
  FROM dbo.foo
  INNER JOIN dbo.SplitStrings(@Values, ',') AS s
    ON s.Item = foo.myField;

On SQL Server 2016 or above (or Azure SQL Database), it is much simpler and more efficient, however you do have to manually apply LTRIM() to take away any leading spaces:

DECLARE @Values varchar(1000) = 'A, B, C';

SELECT blah
  FROM dbo.foo
  INNER JOIN STRING_SPLIT(@Values, ',') AS s
    ON LTRIM(s.value) = foo.myField;

How to change color of Android ListView separator line?

You can set this value in a layout xml file using android:divider="#FF0000". If you are changing the colour/drawable, you have to set/reset the height of the divider too.

<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content">

  <ListView 
    android:id="@+id/android:list"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:divider="#FFCC00"
    android:dividerHeight="4px"/>

</LinearLayout>

SQL Query for Logins

Have a look in the syslogins or sysusers tables in the master schema. Not sure if this still still around in more recent MSSQL versions though. In MSSQL 2005 there are views called sys.syslogins and sys.sysusers.

Java HTTPS client certificate authentication

Other answers show how to globally configure client certificates. However if you want to programmatically define the client key for one particular connection, rather than globally define it across every application running on your JVM, then you can configure your own SSLContext like so:

String keyPassphrase = "";

KeyStore keyStore = KeyStore.getInstance("PKCS12");
keyStore.load(new FileInputStream("cert-key-pair.pfx"), keyPassphrase.toCharArray());

SSLContext sslContext = SSLContexts.custom()
        .loadKeyMaterial(keyStore, null)
        .build();

HttpClient httpClient = HttpClients.custom().setSSLContext(sslContext).build();
HttpResponse response = httpClient.execute(new HttpGet("https://example.com"));

Switch php versions on commandline ubuntu 16.04

From PHP 5.6 => PHP 7.1

$ sudo a2dismod php5.6
$ sudo a2enmod php7.1

for old linux versions

 $ sudo service apache2 restart

for more recent version

$ systemctl restart apache2

Axios Delete request with body and headers?

Actually, axios.delete supports a request body.
It accepts two parameters: a URL and an optional config. That is...

axios.delete(url: string, config?: AxiosRequestConfig | undefined)

You can do the following to set the response body for the delete request:

let config = { 
    headers: {
        Authorization: authToken
    },
    data: { //! Take note of the `data` keyword. This is the request body.
        key: value,
        ... //! more `key: value` pairs as desired.
    } 
}

axios.delete(url, config)

I hope this helps someone!

Prevent users from submitting a form by hitting Enter

Use:

// Validate your form using the jQuery onsubmit function... It'll really work...

$(document).ready(function(){
   $(#form).submit(e){
       e.preventDefault();
       if(validation())
          document.form1.submit();
   });
});

function validation()
{
   // Your form checking goes here.
}

<form id='form1' method='POST' action=''>
    // Your form data
</form>

Permanently add a directory to PYTHONPATH?

Instead of manipulating PYTHONPATH you can also create a path configuration file. First find out in which directory Python searches for this information:

python -m site --user-site

For some reason this doesn't seem to work in Python 2.7. There you can use:

python -c 'import site; site._script()' --user-site

Then create a .pth file in that directory containing the path you want to add (create the directory if it doesn't exist).

For example:

# find directory
SITEDIR=$(python -m site --user-site)

# create if it doesn't exist
mkdir -p "$SITEDIR"

# create new .pth file with our path
echo "$HOME/foo/bar" > "$SITEDIR/somelib.pth"

Non-alphanumeric list order from os.listdir()

I think by default the order is determined with the ASCII value. The solution to this problem is this

dir = sorted(os.listdir(os.getcwd()), key=len)

How do I get total physical memory size using PowerShell without WMI?

I'd like to make a note of this for people referencing in the future.

I wanted to avoid WMI because it uses a DCOM protocol, requiring the remote computer to have the necessary permissions, which could only be setup manually on that remote computer.

So, I wanted to avoid using WMI, but using get-counter often times didn't have the performance counter I wanted.

The solution I used was the Common Information Model (CIM). Unlike WMI, CIM doesn't use DCOM by default. Instead of returning WMI objects, CIM cmdlets return PowerShell objects.

CIM uses the Ws-MAN protocol by default, but it only works with computers that have access to Ws-Man 3.0 or later. So, earlier versions of PowerShell wouldn't be able to issue CIM cmdlets.

The cmdlet I ended up using to get total physical memory size was:

get-ciminstance -class "cim_physicalmemory" | % {$_.Capacity}

how to run two commands in sudo?

I usually do:

sudo bash -c 'whoami; whoami'

How do I make HttpURLConnection use a proxy?

Since java 1.5 you can also pass a java.net.Proxy instance to the openConnection(proxy) method:

//Proxy instance, proxy ip = 10.0.0.1 with port 8080
Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress("10.0.0.1", 8080));
conn = new URL(urlString).openConnection(proxy);

If your proxy requires authentication it will give you response 407.

In this case you'll need the following code:

    Authenticator authenticator = new Authenticator() {

        public PasswordAuthentication getPasswordAuthentication() {
            return (new PasswordAuthentication("user",
                    "password".toCharArray()));
        }
    };
    Authenticator.setDefault(authenticator);

Python "expected an indented block"

#option = 1
#while option != 0:

print ("MENU")
print("please make a selection")
print("1. count")
print("0. quit")
option = int(input("MAKE Your Selection  "))
if option == 1:
    print("1. count up")
    print("2. count down")
    print("0. go back")
    option = int(input("MAKE Your Selection  "))
    if option == 1:
        x = int(input("please enter a number   "))
        for x in range(1, x, 1):
            print (x)

    elif option == 2:
        x = int(input("please enter a number   "))
        for x in range(x, 0, -1):
            print (x) 
    elif option == 0:
        print("hi")
    else:
        print("invalid command")
else:
    print ("H!111")
_________________________________________________________________________


You can try this code! It works.

Why declare unicode by string in python?

The header definition is to define the encoding of the code itself, not the resulting strings at runtime.

putting a non-ascii character like ? in the python script without the utf-8 header definition will throw a warning

error

Fatal error: Call to a member function fetch_assoc() on a non-object

I happen to miss spaces in my query and this error comes.

Ex: $sql= "SELECT * FROM";
$sql .= "table1";

Though the example might look simple, when coding complex queries, the probability for this error is high. I was missing space before word "table1".

Where in memory are my variables stored in C?

I am referring to these variables only from the C perspective.

From the perspective of the C language, all that matters is extent, scope, linkage, and access; exactly how items are mapped to different memory segments is up to the individual implementation, and that will vary. The language standard doesn't talk about memory segments at all. Most modern architectures act mostly the same way; block-scope variables and function arguments will be allocated from the stack, file-scope and static variables will be allocated from a data or code segment, dynamic memory will be allocated from a heap, some constant data will be stored in read-only segments, etc.

How to convert float to int with Java

Using Math.round() will round the float to the nearest integer.

How to import multiple .csv files at once?

I like the approach using list.files(), lapply() and list2env() (or fs::dir_ls(), purrr::map() and list2env()). That seems simple and flexible.

Alternatively, you may try the small package {tor} (to-R): By default it imports files from the working directory into a list (list_*() variants) or into the global environment (load_*() variants).

For example, here I read all the .csv files from my working directory into a list using tor::list_csv():

library(tor)

dir()
#>  [1] "_pkgdown.yml"     "cran-comments.md" "csv1.csv"        
#>  [4] "csv2.csv"         "datasets"         "DESCRIPTION"     
#>  [7] "docs"             "inst"             "LICENSE.md"      
#> [10] "man"              "NAMESPACE"        "NEWS.md"         
#> [13] "R"                "README.md"        "README.Rmd"      
#> [16] "tests"            "tmp.R"            "tor.Rproj"

list_csv()
#> $csv1
#>   x
#> 1 1
#> 2 2
#> 
#> $csv2
#>   y
#> 1 a
#> 2 b

And now I load those files into my global environment with tor::load_csv():

# The working directory contains .csv files
dir()
#>  [1] "_pkgdown.yml"     "cran-comments.md" "CRAN-RELEASE"    
#>  [4] "csv1.csv"         "csv2.csv"         "datasets"        
#>  [7] "DESCRIPTION"      "docs"             "inst"            
#> [10] "LICENSE.md"       "man"              "NAMESPACE"       
#> [13] "NEWS.md"          "R"                "README.md"       
#> [16] "README.Rmd"       "tests"            "tmp.R"           
#> [19] "tor.Rproj"

load_csv()

# Each file is now available as a dataframe in the global environment
csv1
#>   x
#> 1 1
#> 2 2
csv2
#>   y
#> 1 a
#> 2 b

Should you need to read specific files, you can match their file-path with regexp, ignore.case and invert.


For even more flexibility use list_any(). It allows you to supply the reader function via the argument .f.

(path_csv <- tor_example("csv"))
#> [1] "C:/Users/LeporeM/Documents/R/R-3.5.2/library/tor/extdata/csv"
dir(path_csv)
#> [1] "file1.csv" "file2.csv"

list_any(path_csv, read.csv)
#> $file1
#>   x
#> 1 1
#> 2 2
#> 
#> $file2
#>   y
#> 1 a
#> 2 b

Pass additional arguments via ... or inside the lambda function.

path_csv %>% 
  list_any(readr::read_csv, skip = 1)
#> Parsed with column specification:
#> cols(
#>   `1` = col_double()
#> )
#> Parsed with column specification:
#> cols(
#>   a = col_character()
#> )
#> $file1
#> # A tibble: 1 x 1
#>     `1`
#>   <dbl>
#> 1     2
#> 
#> $file2
#> # A tibble: 1 x 1
#>   a    
#>   <chr>
#> 1 b

path_csv %>% 
  list_any(~read.csv(., stringsAsFactors = FALSE)) %>% 
  map(as_tibble)
#> $file1
#> # A tibble: 2 x 1
#>       x
#>   <int>
#> 1     1
#> 2     2
#> 
#> $file2
#> # A tibble: 2 x 1
#>   y    
#>   <chr>
#> 1 a    
#> 2 b

SQL Server - calculate elapsed time between two datetime stamps in HH:MM:SS format

DECLARE @EndTime AS DATETIME, @StartTime AS DATETIME

SELECT @StartTime = '2013-03-08 08:00:00', @EndTime = '2013-03-08 08:30:00'

SELECT CAST(@EndTime - @StartTime AS TIME)

Result: 00:30:00.0000000

Format result as you see fit.

sorting dictionary python 3

Python's ordinary dicts cannot be made to provide the keys/elements in any specific order. For that, you could use the OrderedDict type from the collections module. Note that the OrderedDict type merely keeps a record of insertion order. You would have to sort the entries prior to initializing the dictionary if you want subsequent views/iterators to return the elements in order every time. For example:

>>> myDic={10: 'b', 3:'a', 5:'c'}
>>> sorted_list=sorted(myDic.items(), key=lambda x: x[0])
>>> myOrdDic = OrderedDict(sorted_list)
>>> myOrdDic.items()
[(3, 'a'), (5, 'c'), (10, 'b')]
>>> myOrdDic[7] = 'd'
>>> myOrdDic.items()
[(3, 'a'), (5, 'c'), (10, 'b'), (7, 'd')]

If you want to maintain proper ordering for newly added items, you really need to use a different data structure, e.g., a binary tree/heap. This approach of building a sorted list and using it to initialize a new OrderedDict() instance is just woefully inefficient unless your data is completely static.

Edit: So, if the object of sorting the data is merely to print it in order, in a format resembling a python dict object, something like the following should suffice:

def pprint_dict(d):
    strings = []
    for k in sorted(d.iterkeys()):
        strings.append("%d: '%s'" % (k, d[k]))
    return '{' + ', '.join(strings) + '}'

Note that this function is not flexible w/r/t the types of the key, value pairs (i.e., it expects the keys to be integers and the corresponding values to be strings). If you need more flexibility, use something like strings.append("%s: %s" % (repr(k), repr(d[k]))) instead.

No input file specified

It worked for me..add on top of .htaccess file. It would disable FastCGI on godaddy shared hosting account.

Options +ExecCGI

addhandler x-httpd-php5-cgi .php

How to test an Internet connection with bash?

Ping your default gateway:

#!/bin/bash
ping -q -w 1 -c 1 `ip r | grep default | cut -d ' ' -f 3` > /dev/null && echo ok || echo error

How do I release memory used by a pandas dataframe?

As noted in the comments, there are some things to try: gc.collect (@EdChum) may clear stuff, for example. At least from my experience, these things sometimes work and often don't.

There is one thing that always works, however, because it is done at the OS, not language, level.

Suppose you have a function that creates an intermediate huge DataFrame, and returns a smaller result (which might also be a DataFrame):

def huge_intermediate_calc(something):
    ...
    huge_df = pd.DataFrame(...)
    ...
    return some_aggregate

Then if you do something like

import multiprocessing

result = multiprocessing.Pool(1).map(huge_intermediate_calc, [something_])[0]

Then the function is executed at a different process. When that process completes, the OS retakes all the resources it used. There's really nothing Python, pandas, the garbage collector, could do to stop that.

What's the difference between a Future and a Promise?

Not sure if this can be an answer but as I see what others have said for someone it may look like you need two separate abstractions for both of these concepts so that one of them (Future) is just a read-only view of the other (Promise) ... but actually this is not needed.

For example take a look at how promises are defined in javascript:

https://promisesaplus.com/

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise

The focus is on the composability using the then method like:

asyncOp1()
.then(function(op1Result){
  // do something
  return asyncOp2();
})
.then(function(op2Result){
  // do something more
  return asyncOp3();
})
.then(function(op3Result){
  // do something even more
  return syncOp4(op3Result);
})
...
.then(function(result){
  console.log(result);
})
.catch(function(error){
  console.log(error);
})

which makes asynchronous computation to look like synchronous:

try {
  op1Result = syncOp1();
  // do something
  op1Result = syncOp2();
  // do something more
  op3Result = syncOp3();
  // do something even more
  syncOp4(op3Result);
  ...
  console.log(result);
} catch(error) {
  console.log(error);
}

which is pretty cool. (Not as cool as async-await but async-await just removes the boilerplate ....then(function(result) {.... from it).

And actually their abstraction is pretty good as the promise constructor

new Promise( function(resolve, reject) { /* do it */ } );

allows you to provide two callbacks which can be used to either complete the Promise successfully or with an error. So that only the code that constructs the Promise can complete it and the code that receives an already constructed Promise object has the read-only view.

With inheritance the above can be achieved if resolve and reject are protected methods.

React ignores 'for' attribute of the label element

For React you must use it's per-define keywords to define html attributes.

class -> className

is used and

for -> htmlFor

is used, as react is case sensitive make sure you must follow small and capital as required.

How can I use a local image as the base image with a dockerfile?

Verified: it works well in Docker 1.7.0.

Don't specify --pull=true when running the docker build command

From this thread on reference locally-built image using FROM at dockerfile:

If you want use the local image as the base image, pass without the option --pull=true
--pull=true will always attempt to pull a newer version of the image.

IIS7 Permissions Overview - ApplicationPoolIdentity

Just to add to the confusion, the (Windows Explorer) Effective Permissions dialog doesn't work for these logins. I have a site "Umbo4" using pass-through authentication, and looked at the user's Effective Permissions in the site root folder. The Check Names test resolved the name "IIS AppPool\Umbo4", but the Effective Permissions shows that the user had no permissions at all on the folder (all checkboxes unchecked).

I then excluded this user from the folder explicitly, using the Explorer Security tab. This resulted in the site failing with a HTTP 500.19 error, as expected. The Effective Permissions however looked exactly as before.

How to pass extra variables in URL with WordPress

To make the round trip "The WordPress Way" on the "front-end" (doesn't work in the context of wp-admin), you need to use 3 WordPress functions:

  • add_query_arg() - to create the URL with your new query variable ('c' in your example)
  • the query_vars filter - to modify the list of public query variables that WordPress knows about (this only works on the front-end, because the WP Query is not used on the back end - wp-admin - so this will also not be available in admin-ajax)
  • get_query_var() - to retrieve the value of your custom query variable passed in your URL.

Note: there's no need to even touch the superglobals ($_GET) if you do it this way.

Example

On the page where you need to create the link / set the query variable:

if it's a link back to this page, just adding the query variable

<a href="<?php echo esc_url( add_query_arg( 'c', $my_value_for_c ) )?>">

if it's a link to some other page

<a href="<?php echo esc_url( add_query_arg( 'c', $my_value_for_c, site_url( '/some_other_page/' ) ) )?>">

In your functions.php, or some plugin file or custom class (front-end only):

function add_custom_query_var( $vars ){
  $vars[] = "c";
  return $vars;
}
add_filter( 'query_vars', 'add_custom_query_var' );

On the page / function where you wish to retrieve and work with the query var set in your URL:

$my_c = get_query_var( 'c' );

On the Back End (wp-admin)

On the back end we don't ever run wp(), so the main WP Query does not get run. As a result, there are no query vars and the query_vars hook is not run.

In this case, you'll need to revert to the more standard approach of examining your $_GET superglobal. The best way to do this is probably:

$my_c = filter_input( INPUT_GET, "c", FILTER_SANITIZE_STRING );

though in a pinch you could do the tried and true

$my_c = isset( $_GET['c'] ? $_GET['c'] : "";

or some variant thereof.

Multiple ping script in Python

import subprocess,os,threading,time
from queue import Queue
lock=threading.Lock()
_start=time.time()
def check(n):
    with open(os.devnull, "wb") as limbo:
                ip="192.168.21.{0}".format(n)
                result=subprocess.Popen(["ping", "-n", "1", "-w", "300", ip],stdout=limbo, stderr=limbo).wait()
                with lock:                    
                    if not result:
                        print (ip, "active")                    
                    else:
                        pass                        

def threader():
    while True:
        worker=q.get()
        check(worker)
        q.task_done()
q=Queue()

for x in range(255):
    t=threading.Thread(target=threader)
    t.daemon=True
    t.start()
for worker in range(1,255):
    q.put(worker)
q.join()
print("Process completed in: ",time.time()-_start)

I think this will be better one.

How to test if JSON object is empty in Java

If you're okay with a hack -

obj.toString().equals("{}");

Serializing the object is expensive and moreso for large objects, but it's good to understand that JSON is transparent as a string, and therefore looking at the string representation is something you can always do to solve a problem.

C++ Singleton design pattern

Your code is correct, except that you didn't declare the instance pointer outside the class. The inside class declarations of static variables are not considered declarations in C++, however this is allowed in other languages like C# or Java etc.

class Singleton
{
   public:
       static Singleton* getInstance( );
   private:
       Singleton( );
       static Singleton* instance;
};
Singleton* Singleton::instance; //we need to declare outside because static variables are global

You must know that Singleton instance doesn't need to be manually deleted by us. We need a single object of it throughout the whole program, so at the end of program execution, it will be automatically deallocated.

Why is my CSS style not being applied?

Posting, since it might be useful for someone in the future:

For me, when I got here, the solution was browser cache. Had to hard refresh Chrome (cmd/ctrl+shift+R) to get the new styles applied, it seems the old ones got cached really "deep".

This question/answer might come in handy for someone. And hard refresh tips for different browsers for those who don't use Chrome.

Git Checkout warning: unable to unlink files, permission denied

All you need to do is provide permissions, run the command below from the root of your project:

    chmod ug+w <directory path>

img onclick call to JavaScript function

In response to the good solution from macek. The solution didn't work for me. I have to bind the values of the datas to the export function. This solution works for me:

function exportToForm(a, b, c, d, e) {
  console.log(a, b, c, d, e);
}

var images = document.getElementsByTagName("img");

for (var i=0, len=images.length, img; i<len; i++) {
  var img = images[i];
  var boundExportToForm = exportToForm.bind(undefined, 
          img.getAttribute("data-a"), 
            img.getAttribute("data-b"),
            img.getAttribute("data-c"),
            img.getAttribute("data-d"),
            img.getAttribute("data-e"))

  img.addEventListener("click", boundExportToForm);
  }

"RangeError: Maximum call stack size exceeded" Why?

The answer with for is correct, but if you really want to use functional style avoiding for statement - you can use the following instead of your expression:

Array.from(Array(1000000), () => Math.random());

The Array.from() method creates a new Array instance from an array-like or iterable object. The second argument of this method is a map function to call on every element of the array.

Following the same idea you can rewrite it using ES2015 Spread operator:

[...Array(1000000)].map(() => Math.random())

In both examples you can get an index of the iteration if you need, for example:

[...Array(1000000)].map((_, i) => i + Math.random())

Sending and receiving UDP packets?

The receiver must set port of receiver to match port set in sender DatagramPacket. For debugging try listening on port > 1024 (e.g. 8000 or 9000). Ports < 1024 are typically used by system services and need admin access to bind on such a port.

If the receiver sends packet to the hard-coded port it's listening to (e.g. port 57) and the sender is on the same machine then you would create a loopback to the receiver itself. Always use the port specified from the packet and in case of production software would need a check in any case to prevent such a case.

Another reason a packet won't get to destination is the wrong IP address specified in the sender. UDP unlike TCP will attempt to send out a packet even if the address is unreachable and the sender will not receive an error indication. You can check this by printing the address in the receiver as a precaution for debugging.

In the sender you set:

 byte [] IP= { (byte)192, (byte)168, 1, 106 };
 InetAddress address = InetAddress.getByAddress(IP);

but might be simpler to use the address in string form:

 InetAddress address = InetAddress.getByName("192.168.1.106");

In other words, you set target as 192.168.1.106. If this is not the receiver then you won't get the packet.

Here's a simple UDP Receiver that works :

import java.io.IOException;
import java.net.*;

public class Receiver {

    public static void main(String[] args) {
        int port = args.length == 0 ? 57 : Integer.parseInt(args[0]);
        new Receiver().run(port);
    }

    public void run(int port) {    
      try {
        DatagramSocket serverSocket = new DatagramSocket(port);
        byte[] receiveData = new byte[8];
        String sendString = "polo";
        byte[] sendData = sendString.getBytes("UTF-8");

        System.out.printf("Listening on udp:%s:%d%n",
                InetAddress.getLocalHost().getHostAddress(), port);     
        DatagramPacket receivePacket = new DatagramPacket(receiveData,
                           receiveData.length);

        while(true)
        {
              serverSocket.receive(receivePacket);
              String sentence = new String( receivePacket.getData(), 0,
                                 receivePacket.getLength() );
              System.out.println("RECEIVED: " + sentence);
              // now send acknowledgement packet back to sender     
              DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length,
                   receivePacket.getAddress(), receivePacket.getPort());
              serverSocket.send(sendPacket);
        }
      } catch (IOException e) {
              System.out.println(e);
      }
      // should close serverSocket in finally block
    }
}

Comparing Java enum members: == or equals()?

Can == be used on enum?

Yes: enums have tight instance controls that allows you to use == to compare instances. Here's the guarantee provided by the language specification (emphasis by me):

JLS 8.9 Enums

An enum type has no instances other than those defined by its enum constants.

It is a compile-time error to attempt to explicitly instantiate an enum type. The final clone method in Enum ensures that enum constants can never be cloned, and the special treatment by the serialization mechanism ensures that duplicate instances are never created as a result of deserialization. Reflective instantiation of enum types is prohibited. Together, these four things ensure that no instances of an enum type exist beyond those defined by the enum constants.

Because there is only one instance of each enum constant, it is permissible to use the == operator in place of the equals method when comparing two object references if it is known that at least one of them refers to an enum constant. (The equals method in Enum is a final method that merely invokes super.equals on its argument and returns the result, thus performing an identity comparison.)

This guarantee is strong enough that Josh Bloch recommends, that if you insist on using the singleton pattern, the best way to implement it is to use a single-element enum (see: Effective Java 2nd Edition, Item 3: Enforce the singleton property with a private constructor or an enum type; also Thread safety in Singleton)


What are the differences between == and equals?

As a reminder, it needs to be said that generally, == is NOT a viable alternative to equals. When it is, however (such as with enum), there are two important differences to consider:

== never throws NullPointerException

enum Color { BLACK, WHITE };

Color nothing = null;
if (nothing == Color.BLACK);      // runs fine
if (nothing.equals(Color.BLACK)); // throws NullPointerException

== is subject to type compatibility check at compile time

enum Color { BLACK, WHITE };
enum Chiral { LEFT, RIGHT };

if (Color.BLACK.equals(Chiral.LEFT)); // compiles fine
if (Color.BLACK == Chiral.LEFT);      // DOESN'T COMPILE!!! Incompatible types!

Should == be used when applicable?

Bloch specifically mentions that immutable classes that have proper control over their instances can guarantee to their clients that == is usable. enum is specifically mentioned to exemplify.

Item 1: Consider static factory methods instead of constructors

[...] it allows an immutable class to make the guarantee that no two equal instances exist: a.equals(b) if and only if a==b. If a class makes this guarantee, then its clients can use the == operator instead of the equals(Object) method, which may result in improved performance. Enum types provide this guarantee.

To summarize, the arguments for using == on enum are:

  • It works.
  • It's faster.
  • It's safer at run-time.
  • It's safer at compile-time.

How to use Bootstrap modal using the anchor tag for Register?

Here is a link to W3Schools that answers your question https://www.w3schools.com/bootstrap/bootstrap_ref_js_modal.asp

Note: For anchor tag elements, omit data-target, and use href="#modalID" instead:

I hope that helps

PHP: cannot declare class because the name is already in use

Another option to include_once or require_once is to use class autoloading. http://php.net/manual/en/language.oop5.autoload.php

Convert factor to integer

You can combine the two functions; coerce to characters thence to numerics:

> fac <- factor(c("1","2","1","2"))
> as.numeric(as.character(fac))
[1] 1 2 1 2

Android Studio suddenly cannot resolve symbols

Another way is to download JDK 1.7 and change the path from Android Studio in the error message..and choose Home folder who is contained in Jdk 1.7 folder

Powershell: How can I stop errors from being displayed in a script?

In some cases you can pipe after the command a Out-Null

command | Out-Null

How to make spring inject value into a static field

I've had a similar requirement: I needed to inject a Spring-managed repository bean into my Person entity class ("entity" as in "something with an identity", for example an JPA entity). A Person instance has friends, and for this Person instance to return its friends, it shall delegate to its repository and query for friends there.

@Entity
public class Person {
    private static PersonRepository personRepository;

    @Id
    @GeneratedValue
    private long id;

    public static void setPersonRepository(PersonRepository personRepository){
        this.personRepository = personRepository;
    }

    public Set<Person> getFriends(){
        return personRepository.getFriends(id);
    }

    ...
}

.

@Repository
public class PersonRepository {

    public Person get Person(long id) {
        // do database-related stuff
    }

    public Set<Person> getFriends(long id) {
        // do database-related stuff
    }

    ...
}

So how did I inject that PersonRepository singleton into the static field of the Person class?

I created a @Configuration, which gets picked up at Spring ApplicationContext construction time. This @Configuration gets injected with all those beans that I need to inject as static fields into other classes. Then with a @PostConstruct annotation, I catch a hook to do all static field injection logic.

@Configuration
public class StaticFieldInjectionConfiguration {

    @Inject
    private PersonRepository personRepository;

    @PostConstruct
    private void init() {
        Person.setPersonRepository(personRepository);
    }
}

How to align this span to the right of the div?

Working with floats is bit messy:

This as many other 'trivial' layout tricks can be done with flexbox.

   div.container {
     display: flex;
     justify-content: space-between;
   }

In 2017 I think this is preferred solution (over float) if you don't have to support legacy browsers: https://caniuse.com/#feat=flexbox

Check fiddle how different float usages compares to flexbox ("may include some competing answers"): https://jsfiddle.net/b244s19k/25/. If you still need to stick with float I recommended third version of course.

Checking oracle sid and database name

Just for completeness, you can also use ORA_DATABASE_NAME.

It might be worth noting that not all of the methods give you the same output:

SQL> select sys_context('userenv','db_name') from dual;

SYS_CONTEXT('USERENV','DB_NAME')
--------------------------------------------------------------------------------
orcl

SQL> select ora_database_name from dual;

ORA_DATABASE_NAME
--------------------------------------------------------------------------------
ORCL.XYZ.COM

SQL> select * from global_name;

GLOBAL_NAME
--------------------------------------------------------------------------------
ORCL.XYZ.COM

Nesting await in Parallel.ForEach

I am a little late to party but you may want to consider using GetAwaiter.GetResult() to run your async code in sync context but as paralled as below;

 Parallel.ForEach(ids, i =>
{
    ICustomerRepo repo = new CustomerRepo();
    // Run this in thread which Parallel library occupied.
    var cust = repo.GetCustomer(i).GetAwaiter().GetResult();
    customers.Add(cust);
});

What is correct content-type for excel files?

Do keep in mind that the file.getContentType could also output application/octet-stream instead of the required application/vnd.openxmlformats-officedocument.spreadsheetml.sheet when you try to upload the file that is already open.

How to parse float with two decimal places in javascript?

Simple JavaScript, string to float:

var it_price = chief_double($("#ContentPlaceHolder1_txt_it_price").val());

function chief_double(num){
    var n = parseFloat(num);
    if (isNaN(n)) {
        return "0";
    }
    else {
        return parseFloat(num);
    }
}

Automatic date update in a cell when another cell's value changes (as calculated by a formula)

You could fill the dependend cell (D2) by a User Defined Function (VBA Macro Function) that takes the value of the C2-Cell as input parameter, returning the current date as ouput.

Having C2 as input parameter for the UDF in D2 tells Excel that it needs to reevaluate D2 everytime C2 changes (that is if auto-calculation of formulas is turned on for the workbook).

EDIT:

Here is some code:

For the UDF:

    Public Function UDF_Date(ByVal data) As Date

        UDF_Date = Now()

    End Function

As Formula in D2:

=UDF_Date(C2)

You will have to give the D2-Cell a Date-Time Format, or it will show a numeric representation of the date-value.

And you can expand the formula over the desired range by draging it if you keep the C2 reference in the D2-formula relative.

Note: This still might not be the ideal solution because every time Excel recalculates the workbook the date in D2 will be reset to the current value. To make D2 only reflect the last time C2 was changed there would have to be some kind of tracking of the past value(s) of C2. This could for example be implemented in the UDF by providing also the address alonside the value of the input parameter, storing the input parameters in a hidden sheet, and comparing them with the previous values everytime the UDF gets called.

Addendum:

Here is a sample implementation of an UDF that tracks the changes of the cell values and returns the date-time when the last changes was detected. When using it, please be aware that:

  • The usage of the UDF is the same as described above.

  • The UDF works only for single cell input ranges.

  • The cell values are tracked by storing the last value of cell and the date-time when the change was detected in the document properties of the workbook. If the formula is used over large datasets the size of the file might increase considerably as for every cell that is tracked by the formula the storage requirements increase (last value of cell + date of last change.) Also, maybe Excel is not capable of handling very large amounts of document properties and the code might brake at a certain point.

  • If the name of a worksheet is changed all the tracking information of the therein contained cells is lost.

  • The code might brake for cell-values for which conversion to string is non-deterministic.

  • The code below is not tested and should be regarded only as proof of concept. Use it at your own risk.

    Public Function UDF_Date(ByVal inData As Range) As Date
    
        Dim wb As Workbook
        Dim dProps As DocumentProperties
        Dim pValue As DocumentProperty
        Dim pDate As DocumentProperty
        Dim sName As String
        Dim sNameDate As String
    
        Dim bDate As Boolean
        Dim bValue As Boolean
        Dim bChanged As Boolean
    
        bDate = True
        bValue = True
    
        bChanged = False
    
    
        Dim sVal As String
        Dim dDate As Date
    
        sName = inData.Address & "_" & inData.Worksheet.Name
        sNameDate = sName & "_dat"
    
        sVal = CStr(inData.Value)
        dDate = Now()
    
        Set wb = inData.Worksheet.Parent
    
        Set dProps = wb.CustomDocumentProperties
    
    On Error Resume Next
    
        Set pValue = dProps.Item(sName)
    
        If Err.Number <> 0 Then
            bValue = False
            Err.Clear
        End If
    
    On Error GoTo 0
    
        If Not bValue Then
            bChanged = True
            Set pValue = dProps.Add(sName, False, msoPropertyTypeString, sVal)
        Else
            bChanged = pValue.Value <> sVal
            If bChanged Then
                pValue.Value = sVal
            End If
        End If
    
    On Error Resume Next
    
        Set pDate = dProps.Item(sNameDate)
    
        If Err.Number <> 0 Then
            bDate = False
            Err.Clear
        End If
    
    On Error GoTo 0
    
        If Not bDate Then
            Set pDate = dProps.Add(sNameDate, False, msoPropertyTypeDate, dDate)
        End If
    
        If bChanged Then
            pDate.Value = dDate
        Else
            dDate = pDate.Value
        End If
    
    
        UDF_Date = dDate
     End Function
    

Make the insertion of the date conditional upon the range.

This has an advantage of not changing the dates unless the content of the cell is changed, and it is in the range C2:C2, even if the sheet is closed and saved, it doesn't recalculate unless the adjacent cell changes.

Adapted from this tip and @Paul S answer

Private Sub Worksheet_Change(ByVal Target As Range)
 Dim R1 As Range
 Dim R2 As Range
 Dim InRange As Boolean
    Set R1 = Range(Target.Address)
    Set R2 = Range("C2:C20")
    Set InterSectRange = Application.Intersect(R1, R2)

  InRange = Not InterSectRange Is Nothing
     Set InterSectRange = Nothing
   If InRange = True Then
     R1.Offset(0, 1).Value = Now()
   End If
     Set R1 = Nothing
     Set R2 = Nothing
 End Sub

How to Change Margin of TextView

Your layout in xml probably already has a layout_margin(Left|Right|etc) attribute in it, which means you need to access the object generated by that xml and modify it.

I found this solution to be very simple:

ViewGroup.MarginLayoutParams mlp = (ViewGroup.MarginLayoutParams) mTextView
        .getLayoutParams();

mlp.setMargins(adjustmentPxs, 0, 0, 0);

break;

Get the LayoutParams instance of your textview, downcast it to MarginLayoutParams, and use the setMargins method to set the margins.

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

Java conveniently has the instanceof operator (JLS 15.20.2) to test if a given object is of a given type.

 if (x instanceof List<?>) {   
    List<?> list = (List<?>) x;
    // do something with list
 } else if (x instanceof Collection<?>) {
    Collection<?> col = (Collection<?>) x;
    // do something with col
 }

One thing should be mentioned here: it's important in these kinds of constructs to check in the right order. You will find that if you had swapped the order of the check in the above snippet, the code will still compile, but it will no longer work. That is the following code doesn't work:

 // DOESN'T WORK! Wrong order!
 if (x instanceof Collection<?>) {
    Collection<?> col = (Collection<?>) x;
    // do something with col
 } else if (x instanceof List<?>) { // this will never be reached!
    List<?> list = (List<?>) x;
    // do something with list
 }

The problem is that a List<?> is-a Collection<?>, so it will pass the first test, and the else means that it will never reach the second test. You have to test from the most specific to the most general type.

Create Directory if it doesn't exist with Ruby

Simple way:

directory_name = "name"
Dir.mkdir(directory_name) unless File.exists?(directory_name)

What is a bus error?

It depends on your OS, CPU, Compiler, and possibly other factors.

In general it means the CPU bus could not complete a command, or suffered a conflict, but that could mean a whole range of things depending on the environment and code being run.

-Adam

Intellij idea subversion checkout error: `Cannot run program "svn"`

Under settings ->verison control -> Subversion, uncheck use command line client. It will work.

Getting "project" nuget configuration is invalid error

NOTE: This is mentioned in the question but restarting Visual Studio fixes the issue in most cases.

Updating Visual Studio to 'Update 2' got it working again.

Tools -> Extensions and Updates ->Visual Studio Update 2

As mentioned in the question and the link i posted therein, I'd already updated NuGet Package Manager to 3.4.4 prior to this and restarted to no avail, so I don't know if the combination of both these actions worked.

Determine Pixel Length of String in Javascript/jQuery?

The contexts used for HTML Canvases have a built-in method for checking the size of a font. This method returns a TextMetrics object, which has a width property that contains the width of the text.

function getWidthOfText(txt, fontname, fontsize){
    if(getWidthOfText.c === undefined){
        getWidthOfText.c=document.createElement('canvas');
        getWidthOfText.ctx=getWidthOfText.c.getContext('2d');
    }
    var fontspec = fontsize + ' ' + fontname;
    if(getWidthOfText.ctx.font !== fontspec)
        getWidthOfText.ctx.font = fontspec;
    return getWidthOfText.ctx.measureText(txt).width;
}

Or, as some of the other users have suggested, you can wrap it in a span element:

function getWidthOfText(txt, fontname, fontsize){
    if(getWidthOfText.e === undefined){
        getWidthOfText.e = document.createElement('span');
        getWidthOfText.e.style.display = "none";
        document.body.appendChild(getWidthOfText.e);
    }
    if(getWidthOfText.e.style.fontSize !== fontsize)
        getWidthOfText.e.style.fontSize = fontsize;
    if(getWidthOfText.e.style.fontFamily !== fontname)
        getWidthOfText.e.style.fontFamily = fontname;
    getWidthOfText.e.innerText = txt;
    return getWidthOfText.e.offsetWidth;
}

EDIT 2020: added font name+size caching at Igor Okorokov's suggestion.

Running a command as Administrator using PowerShell?

I have found a way to do this...

Create a batch file to open your script:

@echo off
START "" "C:\Scripts\ScriptName.ps1"

Then create a shortcut, on your desktop say (right click New -> Shortcut).

Then paste this into the location:

C:\Windows\System32\runas.exe /savecred /user:*DOMAIN*\*ADMIN USERNAME* C:\Scripts\BatchFileName.bat

When first opening, you will have to enter your password once. This will then save it in the Windows credential manager.

After this you should then be able to run as administrator without having to enter a administrator username or password.

How can you search Google Programmatically Java API

As an alternative to BalusC answer as it has been deprecated and you have to use proxies, you can use this package. Code sample:

Map<String, String> parameter = new HashMap<>();
parameter.put("q", "Coffee");
parameter.put("location", "Portland");
GoogleSearchResults serp = new GoogleSearchResults(parameter);

JsonObject data = serp.getJson();
JsonArray results = (JsonArray) data.get("organic_results");
JsonObject first_result = results.get(0).getAsJsonObject();
System.out.println("first coffee: " + first_result.get("title").getAsString());

Library on GitHub

How to make modal dialog in WPF?

Given a Window object myWindow, myWindow.Show() will open it modelessly and myWindow.ShowDialog() will open it modally. However, even the latter doesn't block, from what I remember.

Constructing pandas DataFrame from values in variables gives "ValueError: If using all scalar values, you must pass an index"

If you have a dictionary you can turn it into a pandas data frame with the following line of code:

pd.DataFrame({"key": d.keys(), "value": d.values()})

How to make a .jar out from an Android Studio project

Simply add this to your java module's build.gradle. It will include dependent libraries in archive.

mainClassName = "com.company.application.Main"

jar {
  manifest { 
    attributes "Main-Class": "$mainClassName"
  }  

  from {
    configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }
  }
}

This will result in [module_name]/build/libs/[module_name].jar file.

Copying text outside of Vim with set mouse=a enabled

em... Keep pressing Shift and then click the right mouse button

How do I make jQuery wait for an Ajax call to finish before it returns?

I am not using $.ajax but the $.post and $.get functions, so if I need to wait for the response, I use this:

$.ajaxSetup({async: false});
$.get("...");

How to run a specific Android app using Terminal?

I keep this build-and-run script handy, whenever I am working from command line:

#!/usr/bin/env bash

PACKAGE=com.example.demo
ACTIVITY=.MainActivity
APK_LOCATION=app/build/outputs/apk/app-debug.apk
echo "Package: $PACKAGE"

echo "Building the project with tasks: $TASKS"
./gradlew $TASKS

echo "Uninstalling $PACKAGE"
adb uninstall $PACKAGE

echo "Installing $APK_LOCATION"
adb install $APK_LOCATION

echo "Starting $ACTIVITY"
adb shell am start -n $PACKAGE/$ACTIVITY

You need to use a Theme.AppCompat theme (or descendant) with this activity

If you need to extend ActionBarActivity you need on your style.xml:

<!-- Base application theme. -->
<style name="AppTheme" parent="AppTheme.Base"/>

<style name="AppTheme.Base" parent="Theme.AppCompat.Light.DarkActionBar">
    <!-- Customize your theme here. -->

If you set as main theme of your application as android:Theme.Material.Light instead of AppTheme.Base then you’ll get an “IllegalStateException:You need to use a Theme.AppCompat theme (or descendant) with this activity” error.

afxwin.h file is missing in VC++ Express Edition

Found this post that may help: http://social.msdn.microsoft.com/forums/en-US/Vsexpressvc/thread/7c274008-80eb-42a0-a79b-95f5afbf6528/

Or shortly, afxwin.h is MFC and MFC is not included in the free version of VC++ (Express Edition).

Google Maps JS API v3 - Simple Multiple Marker Example

This is the working example map image

var arr = new Array();
    function initialize() { 
        var i;  
        var Locations = [
                {
                  lat:48.856614, 
                  lon:2.3522219000000177, 
                  address:'Paris',
                  gval:'25.5',
                  aType:'Non-Commodity',
                  title:'Paris',
                  descr:'Paris'           
                },        
                    {
                  lat: 55.7512419, 
                  lon: 37.6184217,
                  address:'Moscow',
                  gval:'11.5',
                  aType:'Non-Commodity',
                  title:'Moscow',
                  descr:'Moscow Airport'              
                },     

                {
              lat:-9.481553000000002, 
              lon:147.190242, 
              address:'Port Moresby',
              gval:'1',
              aType:'Oil',
              title:'Papua New Guinea',
              descr:'Papua New Guinea 123123123'              
            },
            {
           lat:20.5200,
           lon:77.7500,
           address:'Indore',
            gval:'1',
            aType:'Oil',
            title:'Indore, India',
            descr:'Airport India'
        }
    ];

    var myOptions = {
        zoom: 2,
        center: new google.maps.LatLng(51.9000,8.4731),
        mapTypeId: google.maps.MapTypeId.ROADMAP
    };

    var map = new google.maps.Map(document.getElementById("map"), myOptions);

    var infowindow =  new google.maps.InfoWindow({
        content: ''
    });

    for (i = 0; i < Locations.length; i++) {
            size=15;        
            var img=new google.maps.MarkerImage('marker.png',           
                new google.maps.Size(size, size),
                new google.maps.Point(0,0),
                new google.maps.Point(size/2, size/2)
           );

        var marker = new google.maps.Marker({
            map: map,
            title: Locations[i].title,
            position: new google.maps.LatLng(Locations[i].lat, Locations[i].lon),           
                icon: img
        });

        bindInfoWindow(marker, map, infowindow, "<p>" + Locations[i].descr + "</p>",Locations[i].title);  

    }

}

function bindInfoWindow(marker, map, infowindow, html, Ltitle) { 
    google.maps.event.addListener(marker, 'mouseover', function() {
            infowindow.setContent(html); 
            infowindow.open(map, marker); 

    });
    google.maps.event.addListener(marker, 'mouseout', function() {
        infowindow.close();

    }); 
} 

Full working example. You can just copy, paste and use.

How to access the contents of a vector from a pointer to the vector in C++?

The easiest way use it as array is use vector::data() member.

Python OpenCV2 (cv2) wrapper to get image size?

cv2 uses numpy for manipulating images, so the proper and best way to get the size of an image is using numpy.shape. Assuming you are working with BGR images, here is an example:

>>> import numpy as np
>>> import cv2
>>> img = cv2.imread('foo.jpg')
>>> height, width, channels = img.shape
>>> print height, width, channels
  600 800 3

In case you were working with binary images, img will have two dimensions, and therefore you must change the code to: height, width = img.shape

Comments in Markdown

You can do this (YAML block):

~~~
# This is a
# multiline
# comment
...

I tried with latex output only, please confirm for others.

Writing to CSV with Python adds blank lines

You need to open the file in binary b mode to take care of blank lines in Python 2. This isn't required in Python 3.

So, change open('test.csv', 'w') to open('test.csv', 'wb').

batch script - read line by line

Try this:

@echo off
for /f "tokens=*" %%a in (input.txt) do (
  echo line=%%a
)
pause

because of the tokens=* everything is captured into %a

edit: to reply to your comment, you would have to do that this way:

@echo off
for /f "tokens=*" %%a in (input.txt) do call :processline %%a

pause
goto :eof

:processline
echo line=%*

goto :eof

:eof

Because of the spaces, you can't use %1, because that would only contain the part until the first space. And because the line contains quotes, you can also not use :processline "%%a" in combination with %~1. So you need to use %* which gets %1 %2 %3 ..., so the whole line.

Detect click outside Angular component

An alternative to AMagyar's answer. This version works when you click on element that gets removed from the DOM with an ngIf.

http://plnkr.co/edit/4mrn4GjM95uvSbQtxrAS?p=preview

_x000D_
_x000D_
  private wasInside = false;_x000D_
  _x000D_
  @HostListener('click')_x000D_
  clickInside() {_x000D_
    this.text = "clicked inside";_x000D_
    this.wasInside = true;_x000D_
  }_x000D_
  _x000D_
  @HostListener('document:click')_x000D_
  clickout() {_x000D_
    if (!this.wasInside) {_x000D_
      this.text = "clicked outside";_x000D_
    }_x000D_
    this.wasInside = false;_x000D_
  }
_x000D_
_x000D_
_x000D_

Detecting a mobile browser

Using Regex (from detectmobilebrowsers.com):

/* eslint-disable */
export const IS_MOBILE = (function (a) {
  return (
    /(android|bb\d+|meego).+mobile|avantgo|bada\/|blackberry|blazer|compal|elaine|fennec|hiptop|iemobile|ip(hone|od)|iris|kindle|lge |maemo|midp|mmp|mobile.+firefox|netfront|opera m(ob|in)i|palm( os)?|phone|p(ixi|re)\/|plucker|pocket|psp|series(4|6)0|symbian|treo|up\.(browser|link)|vodafone|wap|windows ce|xda|xiino/i.test(a)||/1207|6310|6590|3gso|4thp|50[1-6]i|770s|802s|a wa|abac|ac(er|oo|s\-)|ai(ko|rn)|al(av|ca|co)|amoi|an(ex|ny|yw)|aptu|ar(ch|go)|as(te|us)|attw|au(di|\-m|r |s )|avan|be(ck|ll|nq)|bi(lb|rd)|bl(ac|az)|br(e|v)w|bumb|bw\-(n|u)|c55\/|capi|ccwa|cdm\-|cell|chtm|cldc|cmd\-|co(mp|nd)|craw|da(it|ll|ng)|dbte|dc\-s|devi|dica|dmob|do(c|p)o|ds(12|\-d)|el(49|ai)|em(l2|ul)|er(ic|k0)|esl8|ez([4-7]0|os|wa|ze)|fetc|fly(\-|_)|g1 u|g560|gene|gf\-5|g\-mo|go(\.w|od)|gr(ad|un)|haie|hcit|hd\-(m|p|t)|hei\-|hi(pt|ta)|hp( i|ip)|hs\-c|ht(c(\-| |_|a|g|p|s|t)|tp)|hu(aw|tc)|i\-(20|go|ma)|i230|iac( |\-|\/)|ibro|idea|ig01|ikom|im1k|inno|ipaq|iris|ja(t|v)a|jbro|jemu|jigs|kddi|keji|kgt( |\/)|klon|kpt |kwc\-|kyo(c|k)|le(no|xi)|lg( g|\/(k|l|u)|50|54|\-[a-w])|libw|lynx|m1\-w|m3ga|m50\/|ma(te|ui|xo)|mc(01|21|ca)|m\-cr|me(rc|ri)|mi(o8|oa|ts)|mmef|mo(01|02|bi|de|do|t(\-| |o|v)|zz)|mt(50|p1|v )|mwbp|mywa|n10[0-2]|n20[2-3]|n30(0|2)|n50(0|2|5)|n7(0(0|1)|10)|ne((c|m)\-|on|tf|wf|wg|wt)|nok(6|i)|nzph|o2im|op(ti|wv)|oran|owg1|p800|pan(a|d|t)|pdxg|pg(13|\-([1-8]|c))|phil|pire|pl(ay|uc)|pn\-2|po(ck|rt|se)|prox|psio|pt\-g|qa\-a|qc(07|12|21|32|60|\-[2-7]|i\-)|qtek|r380|r600|raks|rim9|ro(ve|zo)|s55\/|sa(ge|ma|mm|ms|ny|va)|sc(01|h\-|oo|p\-)|sdk\/|se(c(\-|0|1)|47|mc|nd|ri)|sgh\-|shar|sie(\-|m)|sk\-0|sl(45|id)|sm(al|ar|b3|it|t5)|so(ft|ny)|sp(01|h\-|v\-|v )|sy(01|mb)|t2(18|50)|t6(00|10|18)|ta(gt|lk)|tcl\-|tdg\-|tel(i|m)|tim\-|t\-mo|to(pl|sh)|ts(70|m\-|m3|m5)|tx\-9|up(\.b|g1|si)|utst|v400|v750|veri|vi(rg|te)|vk(40|5[0-3]|\-v)|vm40|voda|vulc|vx(52|53|60|61|70|80|81|83|85|98)|w3c(\-| )|webc|whit|wi(g |nc|nw)|wmlb|wonu|x700|yas\-|your|zeto|zte\-/i
      .test(
        a.substr(0,4)
      )
  )
  // @ts-ignore
})(navigator.userAgent || navigator.vendor || window.opera)
/* eslint-enable */

Copy files on Windows Command Line with Progress

This technet link has some good info for copying large files. I used an exchange server utility mentioned in the article which shows progress and uses non buffered copy functions internally for faster transfer.

In another scenario, I used robocopy. Robocopy GUI makes it easier to get your command line options right.

How to check whether dynamically attached event listener exists or not?

I did something like that:

const element = document.getElementById('div');

if (element.getAttribute('listener') !== 'true') {
     element.addEventListener('click', function (e) {
         const elementClicked = e.target;
         elementClicked.setAttribute('listener', 'true');
         console.log('event has been attached');
    });
}

Creating a special attribute for an element when the listener is attached and then checking if it exists.

How do I find the size of a struct?

I suspect you mean 'struct', not 'strict', and 'char' instead of 'Char'.

The size will be implementation dependent. On most 32-bit systems, it will probably be 5 -- 4 bytes for the pointer, one for the char. I don't believe alignment will come into play here. If you swapped 'c' and 'b', however, the size may grow to 8 bytes.

Ok, I tried it out (g++ 4.2.3, with -g option) and I get 8.

Memcached vs. Redis?

Memcached is good at being a simple key/value store and is good at doing key => STRING. This makes it really good for session storage.

Redis is good at doing key => SOME_OBJECT.

It really depends on what you are going to be putting in there. My understanding is that in terms of performance they are pretty even.

Also good luck finding any objective benchmarks, if you do find some kindly send them my way.

Align the form to the center in Bootstrap 4

<div class="d-flex justify-content-center align-items-center container ">

    <div class="row ">


        <form action="">
            <div class="form-group">
                <label for="inputUserName" class="control-label">Enter UserName</label>
                <input type="email" class="form-control" id="inputUserName" aria-labelledby="emailnotification">
                <small id="emailnotification" class="form-text text-muted">Enter Valid Email Id</small>
            </div>
            <div class="form-group">
                <label for="inputPassword" class="control-label">Enter Password</label>
                <input type="password" class="form-control" id="inputPassword" aria-labelledby="passwordnotification">

            </div>
        </form>

    </div>

</div>

Read tab-separated file line into array

You could also try,

OIFS=$IFS;
IFS="\t";

animals=`cat animals.txt`
animalArray=$animals;

for animal in $animalArray
do
    echo $animal
done

IFS=$OIFS;

Content Security Policy: The page's settings blocked the loading of a resource

You can disable them in your browser.

Firefox

Type about:config in the Firefox address bar and find security.csp.enable and set it to false.

Chrome

You can install the extension called Disable Content-Security-Policy to disable CSP.

In Ruby on Rails, what's the difference between DateTime, Timestamp, Time and Date?

Here is an awesome and precise explanation I found.

TIMESTAMP used to track changes of records, and update every time when the record is changed. DATETIME used to store specific and static value which is not affected by any changes in records.

TIMESTAMP also affected by different TIME ZONE related setting. DATETIME is constant.

TIMESTAMP internally converted a current time zone to UTC for storage, and during retrieval convert the back to the current time zone. DATETIME can not do this.

TIMESTAMP is 4 bytes and DATETIME is 8 bytes.

TIMESTAMP supported range: ‘1970-01-01 00:00:01' UTC to ‘2038-01-19 03:14:07' UTC DATETIME supported range: ‘1000-01-01 00:00:00' to ‘9999-12-31 23:59:59'

source: https://www.dbrnd.com/2015/09/difference-between-datetime-and-timestamp-in-mysql/#:~:text=DATETIME%20vs%20TIMESTAMP%3A,DATETIME%20is%20constant.

Also...

table with different column "date" types and corresponding rails migration types depending on the database

How to query nested objects?

Since there is a lot of confusion about queries MongoDB collection with sub-documents, I thought its worth to explain the above answers with examples:

First I have inserted only two objects in the collection namely: message as:

> db.messages.find().pretty()
{
    "_id" : ObjectId("5cce8e417d2e7b3fe9c93c32"),
    "headers" : {
        "From" : "[email protected]"
    }
}
{
    "_id" : ObjectId("5cce8eb97d2e7b3fe9c93c33"),
    "headers" : {
        "From" : "[email protected]",
        "To" : "[email protected]"
    }
}
>

So what is the result of query: db.messages.find({headers: {From: "[email protected]"} }).count()

It should be one because these queries for documents where headers equal to the object {From: "[email protected]"}, only i.e. contains no other fields or we should specify the entire sub-document as the value of a field.

So as per the answer from @Edmondo1984

Equality matches within sub-documents select documents if the subdocument matches exactly the specified sub-document, including the field order.

From the above statements, what is the below query result should be?

> db.messages.find({headers: {To: "[email protected]", From: "[email protected]"}  }).count()
0

And what if we will change the order of From and To i.e same as sub-documents of second documents?

> db.messages.find({headers: {From: "[email protected]", To: "[email protected]"}  }).count()
1

so, it matches exactly the specified sub-document, including the field order.

For using dot operator, I think it is very clear for every one. Let's see the result of below query:

> db.messages.find( { 'headers.From': "[email protected]" }  ).count()
2

I hope these explanations with the above example will make someone more clarity on find query with sub-documents.

Set textbox to readonly and background color to grey in jquery

there are 2 solutions:

visit this jsfiddle

in your css you can add this:
     .input-disabled{background-color:#EBEBE4;border:1px solid #ABADB3;padding:2px 1px;}

in your js do something like this:
     $('#test').attr('readonly', true);
     $('#test').addClass('input-disabled');

Hope this help.

Another way is using hidden input field as mentioned by some of the comments. However bear in mind that, in the backend code, you need to make sure you validate this newly hidden input at correct scenario. Hence I'm not recommend this way as it will create more bugs if its not handle properly.

JSON response parsing in Javascript to get key/value pair

Ok, here is the JS code:

var data = JSON.parse('{"c":{"a":{"name":"cable - black","value":2}}}')

for (var event in data) {
    var dataCopy = data[event];
    for (data in dataCopy) {
        var mainData = dataCopy[data];
        for (key in mainData) {
            if (key.match(/name|value/)) {
                alert('key : ' + key + ':: value : ' + mainData[key])
            }
        }
    }
}?

FIDDLE HERE

Maven parent pom vs modules pom

From my experience and Maven best practices there are two kinds of "parent poms"

  • "company" parent pom - this pom contains your company specific information and configuration that inherit every pom and doesn't need to be copied. These informations are:

    • repositories
    • distribution managment sections
    • common plugins configurations (like maven-compiler-plugin source and target versions)
    • organization, developers, etc

    Preparing this parent pom need to be done with caution, because all your company poms will inherit from it, so this pom have to be mature and stable (releasing a version of parent pom should not affect to release all your company projects!)

  • second kind of parent pom is a multimodule parent. I prefer your first solution - this is a default maven convention for multi module projects, very often represents VCS code structure

The intention is to be scalable to a large scale build so should be scalable to a large number of projects and artifacts.

Mutliprojects have structure of trees - so you aren't arrown down to one level of parent pom. Try to find a suitable project struture for your needs - a classic exmample is how to disrtibute mutimodule projects

distibution/
documentation/
myproject/
  myproject-core/
  myproject-api/
  myproject-app/
  pom.xml
pom.xml

A few bonus questions:

  • Where is the best place to define the various shared configuration as in source control, deployment directories, common plugins etc. (I'm assuming the parent but I've often been bitten by this and they've ended up in each project rather than a common one).

This configuration has to be wisely splitted into a "company" parent pom and project parent pom(s). Things related to all you project go to "company" parent and this related to current project go to project one's.

  • How do the maven-release plugin, hudson and nexus deal with how you set up your multi-projects (possibly a giant question, it's more if anyone has been caught out when by how a multi-project build has been set up)?

Company parent pom have to be released first. For multiprojects standard rules applies. CI server need to know all to build the project correctly.

Mysql SELECT CASE WHEN something then return field

You are mixing the 2 different CASE syntaxes inappropriately.

Use this style (Searched)

  CASE  
  WHEN u.nnmu ='0' THEN mu.naziv_mesta
  WHEN u.nnmu ='1' THEN m.naziv_mesta
 ELSE 'GRESKA'
 END as mesto_utovara,

Or this style (Simple)

  CASE u.nnmu 
  WHEN '0' THEN mu.naziv_mesta
  WHEN '1' THEN m.naziv_mesta
 ELSE 'GRESKA'
 END as mesto_utovara,

Not This (Simple but with boolean search predicates)

  CASE u.nnmu 
  WHEN u.nnmu ='0' THEN mu.naziv_mesta
  WHEN u.nnmu ='1' THEN m.naziv_mesta
 ELSE 'GRESKA'
 END as mesto_utovara,

In MySQL this will end up testing whether u.nnmu is equal to the value of the boolean expression u.nnmu ='0' itself. Regardless of whether u.nnmu is 1 or 0 the result of the case expression itself will be 1

For example if nmu = '0' then (nnmu ='0') evaluates as true (1) and (nnmu ='1') evaluates as false (0). Substituting these into the case expression gives

 SELECT CASE  '0'
  WHEN 1 THEN '0'
  WHEN 0 THEN '1'
 ELSE 'GRESKA'
 END as mesto_utovara

if nmu = '1' then (nnmu ='0') evaluates as false (0) and (nnmu ='1') evaluates as true (1). Substituting these into the case expression gives

 SELECT CASE  '1'
  WHEN 0 THEN '0'
  WHEN 1 THEN '1'
 ELSE 'GRESKA'
 END as mesto_utovara

NodeJS - What does "socket hang up" actually mean?

After a long debug into node js code, mongodb connection string, checking CORS etc, For me just switching to a different port number server.listen(port); made it work, into postman, try that too. No changes to proxy settings just the defaults.

Install msi with msiexec in a Specific Directory

Actually, both INSTALLPATH/TARGETDIR are correct. It depends on how MSI processes this.

I create a MSG using wixToolSet. In WXS file, there is "Directory" Node, which root dir maybe like the following:

<Directory Id="**TARGETDIR**" Name="SourceDir">;

As you can see: Id is which you should use.

Mockito - difference between doReturn() and when()

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

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

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

How do I style (css) radio buttons and labels?

This will get your buttons and labels next to each other, at least. I believe the second part can't be done in css alone, and will need javascript. I found a page that might help you with that part as well, but I don't have time right now to try it out: http://www.webmasterworld.com/forum83/6942.htm

<style type="text/css">
.input input {
  float: left;
}
.input label {
  margin: 5px;
}
</style>
<div class="input radio">
    <fieldset>
        <legend>What color is the sky?</legend>
        <input type="hidden" name="data[Submit][question]" value="" id="SubmitQuestion" />

        <input type="radio" name="data[Submit][question]" id="SubmitQuestion1" value="1"  />
        <label for="SubmitQuestion1">A strange radient green.</label>

        <input type="radio" name="data[Submit][question]" id="SubmitQuestion2" value="2"  />
        <label for="SubmitQuestion2">A dark gloomy orange</label>
        <input type="radio" name="data[Submit][question]" id="SubmitQuestion3" value="3"  />
        <label for="SubmitQuestion3">A perfect glittering blue</label>
    </fieldset>
</div>

Can I embed a .png image into an html page?

The 64base method works for large images as well, I use that method to embed all the images into my website, and it works every time. I've done with files up to 2Mb size, jpg and png.

Java, How to specify absolute value and square roots

int currentNum = 5;
double sqrRoot = 0.0;
int sqrRootInt = 0;



sqrRoot=Math.sqrt(currentNum);
sqrRootInt= (int)sqrRoot;

creating charts with angularjs

angular-charts is a library I wrote for creating charts with angular and D3.

It encapsulates basic charts that can be created using D3 in one angular directive. Also it offers features such as

  1. One click chart change;
  2. Auto tooltips;
  3. Auto adjustment to containers;
  4. Legends;
  5. Simple data format: only define what you on x and what you need on y;

There is a angular-charts demo available.

How to send email from MySQL 5.1

If you have an SMTP service running, you can outfile to the drop directory. If you have high volume, you may result with duplicate file names, but there are ways to avoid that.

Otherwise, you will need to create a UDF.

Here's a sample trigger solution:

CREATE TRIGGER test.autosendfromdrop BEFORE INSERT ON test.emaildrop
FOR EACH ROW BEGIN
      /* START THE WRITING OF THE EMAIL FILE HERE*/      
      SELECT  concat("To: ",NEW.To),
              concat("From: ",NEW.From),
              concat("Subject: ",NEW.Subject),
              NEW.Body
          INTO OUTFILE 
                   "C:\\inetpub\\mailroot\\pickup\\mail.txt" 
              FIELDS TERMINATED by '\r\n' ESCAPED BY '';            
END;

To markup the message body you will need something like this...

CREATE FUNCTION `HTMLBody`(Msg varchar(8192)) 
    RETURNS varchar(17408) CHARSET latin1 DETERMINISTIC
BEGIN
  declare tmpMsg varchar(17408);
  set tmpMsg = cast(concat(
      'Date: ',date_format(NOW(),'%e %b %Y %H:%i:%S -0600'),'\r\n',
      'MIME-Version: 1.0','\r\n',
      'Content-Type: multipart/alternative;','\r\n',
      ' boundary=\"----=_NextPart_000_0000_01CA4B3F.8C263EE0\"','\r\n',
      'Content-Class: urn:content-classes:message','\r\n',
      'Importance: normal','\r\n',
      'Priority: normal','\r\n','','\r\n','','\r\n',
      'This is a multi-part message in MIME format.','\r\n','','\r\n',
      '------=_NextPart_000_0000_01CA4B3F.8C263EE0','\r\n',
      'Content-Type: text/plain;','\r\n',
      '  charset=\"iso-8859-1\"','\r\n',
      'Content-Transfer-Encoding: 7bit','\r\n','','\r\n','','\r\n',
      Msg,
      '\r\n','','\r\n','','\r\n',
      '------=_NextPart_000_0000_01CA4B3F.8C263EE0','\r\n',
      'Content-Type: text/html','\r\n',
      'Content-Transfer-Encoding: 7bit','\r\n','','\r\n',
      Msg,
      '\r\n','------=_NextPart_000_0000_01CA4B3F.8C263EE0--'
      ) as char);
  RETURN tmpMsg;
END ;