Programs & Examples On #Ews managed api

Exchange Web Services (EWS) API that can be used to access Exchange resources.

How can I detect if this dictionary key exists in C#?

I use a Dictionary and because of the repetetiveness and possible missing keys, I quickly patched together a small method:

 private static string GetKey(IReadOnlyDictionary<string, string> dictValues, string keyValue)
 {
     return dictValues.ContainsKey(keyValue) ? dictValues[keyValue] : "";
 }

Calling it:

var entry = GetKey(dictList,"KeyValue1");

Gets the job done.

Python memory usage of numpy arrays

In python notebooks I often want to filter out 'dangling' numpy.ndarray's, in particular the ones that are stored in _1, _2, etc that were never really meant to stay alive.

I use this code to get a listing of all of them and their size.

Not sure if locals() or globals() is better here.

import sys
import numpy
from humanize import naturalsize

for size, name in sorted(
    (value.nbytes, name)
    for name, value in locals().items()
    if isinstance(value, numpy.ndarray)):
  print("{:>30}: {:>8}".format(name, naturalsize(size)))

Setting focus to iframe contents

Try listening for events in the parent document and passing the event to a handler in the iframe document.

String to date in Oracle with milliseconds

Oracle stores only the fractions up to second in a DATE field.

Use TIMESTAMP instead:

SELECT  TO_TIMESTAMP('2004-09-30 23:53:48,140000000', 'YYYY-MM-DD HH24:MI:SS,FF9')
FROM    dual

, possibly casting it to a DATE then:

SELECT  CAST(TO_TIMESTAMP('2004-09-30 23:53:48,140000000', 'YYYY-MM-DD HH24:MI:SS,FF9') AS DATE)
FROM    dual

Creating a UITableView Programmatically

- (void)viewDidLoad
{
    [super viewDidLoad];
    tableView = [[UITableView alloc] initWithFrame:self.view.bounds style:UITableViewStylePlain];
    tableView.delegate = self;
    tableView.dataSource = self;

    tableView.backgroundColor = [UIColor grayColor];

    // add to superview
    [self.view addSubview:tableView];
}

#pragma mark - UITableViewDataSource
- (NSInteger)numberOfSectionsInTableView:(UITableView *)theTableView
{
    return 1;
}

- (NSInteger)tableView:(UITableView *)theTableView numberOfRowsInSection:    (NSInteger)section
{
    return 1;
}

// the cell will be returned to the tableView
- (UITableViewCell *)tableView:(UITableView *)theTableView  cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *cellIdentifier = @"HistoryCell";

    // Similar to UITableViewCell, but 
    UITableViewCell *cell = (UITableViewCell *)[theTableView dequeueReusableCellWithIdentifier:cellIdentifier];
    if (cell == nil)
    {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
    }
    cell.descriptionLabel.text = @"Testing";
    return cell;
}

Java - Convert int to Byte Array of 4 Bytes?

You can convert yourInt to bytes by using a ByteBuffer like this:

return ByteBuffer.allocate(4).putInt(yourInt).array();

Beware that you might have to think about the byte order when doing so.

How can I subset rows in a data frame in R based on a vector of values?

If you really just want to subset each data frame by an index that exists in both data frames, you can do this with the 'match' function, like so:

data_A[match(data_B$index, data_A$index, nomatch=0),]
data_B[match(data_A$index, data_B$index, nomatch=0),]

This is, though, the same as:

data_A[data_A$index %in% data_B$index,]
data_B[data_B$index %in% data_A$index,]

Here is a demo:

# Set seed for reproducibility.
set.seed(1)

# Create two sample data sets.
data_A <- data.frame(index=sample(1:200, 90, rep=FALSE), value=runif(90))
data_B <- data.frame(index=sample(1:200, 120, rep=FALSE), value=runif(120))

# Subset data of each data frame by the index in the other.
t_A <- data_A[match(data_B$index, data_A$index, nomatch=0),]
t_B <- data_B[match(data_A$index, data_B$index, nomatch=0),]

# Make sure they match.
data.frame(t_A[order(t_A$index),], t_B[order(t_B$index),])[1:20,]

#    index     value index.1    value.1
# 27     3 0.7155661       3 0.65887761
# 10    12 0.6049333      12 0.14362694
# 88    14 0.7410786      14 0.42021589
# 56    15 0.4525708      15 0.78101754
# 38    18 0.2075451      18 0.70277874
# 24    23 0.4314737      23 0.78218212
# 34    32 0.1734423      32 0.85508236
# 22    38 0.7317925      38 0.56426384
# 84    39 0.3913593      39 0.09485786
# 5     40 0.7789147      40 0.31248966
# 74    43 0.7799849      43 0.10910096
# 71    45 0.2847905      45 0.26787813
# 57    46 0.1751268      46 0.17719454
# 25    48 0.1482116      48 0.99607737
# 81    53 0.6304141      53 0.26721208
# 60    58 0.8645449      58 0.96920881
# 30    59 0.6401010      59 0.67371223
# 75    61 0.8806190      61 0.69882454
# 63    64 0.3287773      64 0.36918946
# 19    70 0.9240745      70 0.11350771

How do I install Python 3 on an AWS EC2 instance?

EC2 (on the Amazon Linux AMI) currently supports python3.4 and python3.5.

sudo yum install python35
sudo yum install python35-pip

Continuous Integration vs. Continuous Delivery vs. Continuous Deployment

lets keep it short :

CI: A software development practice where members of a team integrate their work at least daily. Each integration is verified by automated build (include tests)to detect error as quick as possible. CD: CD Builds on CI, where you build software in such a way that the software can be released to production at any time.

PKIX path building failed: unable to find valid certification path to requested target

You need to set certificate to hit this url. use below code to set keystore:

System.setProperty("javax.net.ssl.trustStore","clientTrustStore.key");

System.setProperty("javax.net.ssl.trustStorePassword","qwerty");

How to call a .NET Webservice from Android using KSOAP2?

I think you can't call

 androidHttpTransport.call(SOAP_ACTION, envelope);

on main Thread.

Network operations should be done on different Thread.

Create another Thread or AsyncTask to call the method.

How to obtain a Thread id in Python?

Using the logging module you can automatically add the current thread identifier in each log entry. Just use one of these LogRecord mapping keys in your logger format string:

%(thread)d : Thread ID (if available).

%(threadName)s : Thread name (if available).

and set up your default handler with it:

logging.basicConfig(format="%(threadName)s:%(message)s")

How to convert DataTable to class Object?

It is Vb.Net version:

Public Class Test
Public Property id As Integer
Public Property name As String
Public Property address As String
Public Property createdDate As Date

End Class

  Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click

    Dim x As Date = Now

    Debug.WriteLine("Begin: " & DateDiff(DateInterval.Second, x, Now) & "-" & Now)

    Dim dt As New DataTable
    dt.Columns.Add("id")
    dt.Columns.Add("name")
    dt.Columns.Add("address")
    dt.Columns.Add("createdDate")

    For i As Integer = 0 To 100000
        dt.Rows.Add(i, "name - " & i, "address - " & i, DateAdd(DateInterval.Second, i, Now))
    Next

    Debug.WriteLine("Datatable created: " & DateDiff(DateInterval.Second, x, Now) & "-" & Now)


    Dim items As IList(Of Test) = dt.AsEnumerable().[Select](Function(row) New _
            Test With {
                        .id = row.Field(Of String)("id"),
                        .name = row.Field(Of String)("name"),
                        .address = row.Field(Of String)("address"),
                        .createdDate = row.Field(Of String)("createdDate")
                       }).ToList()

    Debug.WriteLine("List created: " & DateDiff(DateInterval.Second, x, Now) & "-" & Now)

    Debug.WriteLine("Complated")

End Sub

How do I assign a port mapping to an existing Docker container?

  1. Stop the docker engine and that container.
  2. Go to /var/lib/docker/containers/${container_id} directory and edit hostconfig.json
  3. Edit PortBindings.HostPort that you want the change.
  4. Start docker engine and container.

Android Spinner : Avoid onItemSelected calls during initialization

haha...I have the same question. When initViews() just do like this.The sequence is the key, listener is the last. Good Luck !

spinner.setAdapter(adapter);
spinner.setSelection(position);
spinner.setOnItemSelectedListener(listener);

Authorize attribute in ASP.NET MVC

One advantage is that you are compiling access into the application, so it cannot accidentally be changed by someone modifying the Web.config.

This may not be an advantage to you, and might be a disadvantage. But for some kinds of access, it may be preferrable.

Plus, I find that authorization information in the Web.config pollutes it, and makes it harder to find things. So in some ways its preference, in others there is no other way to do it.

C++ template typedef

C++11 added alias declarations, which are generalization of typedef, allowing templates:

template <size_t N>
using Vector = Matrix<N, 1>;

The type Vector<3> is equivalent to Matrix<3, 1>.


In C++03, the closest approximation was:

template <size_t N>
struct Vector
{
    typedef Matrix<N, 1> type;
};

Here, the type Vector<3>::type is equivalent to Matrix<3, 1>.

Most efficient T-SQL way to pad a varchar on the left to a certain length?

Here is my solution. I can pad any character and it is fast. Went with simplicity. You can change variable size to meet your needs.

Updated with a parameter to handle what to return if null: null will return a null if null

CREATE OR ALTER FUNCTION code.fnConvert_PadLeft(
    @in_str nvarchar(1024),
    @pad_length int, 
    @pad_char nchar(1) = ' ', 
    @rtn_null NVARCHAR(1024) = '')
RETURNS NVARCHAR(1024)
AS
BEGIN
     DECLARE @rtn  NCHAR(1024) = ' '
     RETURN RIGHT(REPLACE(@rtn,' ',@pad_char)+ISNULL(@in_str,@rtn_null), @pad_length)
END
GO

CREATE OR ALTER FUNCTION code.fnConvert_PadRight(
    @in_str nvarchar(1024), 
    @pad_length int, 
    @pad_char nchar(1) = ' ', 
    @rtn_null NVARCHAR(1024) = '')
RETURNS NVARCHAR(1024)
AS
BEGIN
     DECLARE @rtn  NCHAR(1024) = ' '
     RETURN LEFT(ISNULL(@in_str,@rtn_null)+REPLACE(@rtn,' ',@pad_char), @pad_length)
END
GO 

-- Example
SET STATISTICS time ON 
SELECT code.fnConvert_PadLeft('88',10,'0',''), 
    code.fnConvert_PadLeft(null,10,'0',''), 
    code.fnConvert_PadLeft(null,10,'0',null), 
    code.fnConvert_PadRight('88',10,'0',''), 
    code.fnConvert_PadRight(null,10,'0',''),
    code.fnConvert_PadRight(null,10,'0',NULL)


0000000088  0000000000  NULL    8800000000  0000000000  NULL

Bash script error [: !=: unary operator expected

Quotes!

if [ "$1" != -v ]; then

Otherwise, when $1 is completely empty, your test becomes:

[ != -v ]

instead of

[ "" != -v ]

...and != is not a unary operator (that is, one capable of taking only a single argument).

Resize a large bitmap file to scaled output file on Android

This is 'Mojo Risin's and 'Ofir's solutions "combined". This will give you a proportionally resized image with the boundaries of max width and max height.

  1. It only reads meta data to get the original size (options.inJustDecodeBounds)
  2. It uses a rought resize to save memory (itmap.createScaledBitmap)
  3. It uses a precisely resized image based on the rough Bitamp created earlier.

For me it has been performing fine on 5 MegaPixel images an below.

try
{
    int inWidth = 0;
    int inHeight = 0;

    InputStream in = new FileInputStream(pathOfInputImage);

    // decode image size (decode metadata only, not the whole image)
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeStream(in, null, options);
    in.close();
    in = null;

    // save width and height
    inWidth = options.outWidth;
    inHeight = options.outHeight;

    // decode full image pre-resized
    in = new FileInputStream(pathOfInputImage);
    options = new BitmapFactory.Options();
    // calc rought re-size (this is no exact resize)
    options.inSampleSize = Math.max(inWidth/dstWidth, inHeight/dstHeight);
    // decode full image
    Bitmap roughBitmap = BitmapFactory.decodeStream(in, null, options);

    // calc exact destination size
    Matrix m = new Matrix();
    RectF inRect = new RectF(0, 0, roughBitmap.getWidth(), roughBitmap.getHeight());
    RectF outRect = new RectF(0, 0, dstWidth, dstHeight);
    m.setRectToRect(inRect, outRect, Matrix.ScaleToFit.CENTER);
    float[] values = new float[9];
    m.getValues(values);

    // resize bitmap
    Bitmap resizedBitmap = Bitmap.createScaledBitmap(roughBitmap, (int) (roughBitmap.getWidth() * values[0]), (int) (roughBitmap.getHeight() * values[4]), true);

    // save image
    try
    {
        FileOutputStream out = new FileOutputStream(pathOfOutputImage);
        resizedBitmap.compress(Bitmap.CompressFormat.JPEG, 80, out);
    }
    catch (Exception e)
    {
        Log.e("Image", e.getMessage(), e);
    }
}
catch (IOException e)
{
    Log.e("Image", e.getMessage(), e);
}

How can I use the python HTMLParser library to extract data from a specific div tag?

Little correction at Line 3

HTMLParser.HTMLParser.__init__(self)

it should be

HTMLParser.__init__(self)

The following worked for me though

import urllib2 

from HTMLParser import HTMLParser  

class MyHTMLParser(HTMLParser):

  def __init__(self):
    HTMLParser.__init__(self)
    self.recording = 0 
    self.data = []
  def handle_starttag(self, tag, attrs):
    if tag == 'required_tag':
      for name, value in attrs:
        if name == 'somename' and value == 'somevale':
          print name, value
          print "Encountered the beginning of a %s tag" % tag 
          self.recording = 1 


  def handle_endtag(self, tag):
    if tag == 'required_tag':
      self.recording -=1 
      print "Encountered the end of a %s tag" % tag 

  def handle_data(self, data):
    if self.recording:
      self.data.append(data)

 p = MyHTMLParser()
 f = urllib2.urlopen('http://www.someurl.com')
 html = f.read()
 p.feed(html)
 print p.data
 p.close()

`

How to use onClick event on react Link component?

You are passing hello() as a string, also hello() means execute hello immediately.

try

onClick={hello}

CSS scale down image to fit in containing div, without specifing original size

if you want both width and the height you can try

 background-size: cover !important;

but this wont distort the image but fill the div.

How to set component default props on React component

You can set the default props using the class name as shown below.

class Greeting extends React.Component {
  render() {
    return (
      <h1>Hello, {this.props.name}</h1>
    );
  }
}

// Specifies the default values for props:
Greeting.defaultProps = {
  name: 'Stranger'
};

You can use the React's recommended way from this link for more info

Less than or equal to

In batch, the > is a redirection sign used to output data into a text file. The compare op's available (And recommended) for cmd are below (quoted from the if /? help):

where compare-op may be one of:

    EQU - equal
    NEQ - not equal
    LSS - less than
    LEQ - less than or equal
    GTR - greater than
    GEQ - greater than or equal

That should explain what you want. The only other compare-op is == which can be switched with the if not parameter. Other then that rely on these three letter ones.

Using Exit button to close a winform program

If you only want to Close the form than you can use this.Close(); else if you want the whole application to be closed use Application.Exit();

How to figure out the SMTP server host?

Quick example:

On Ubuntu, if you are interested, for instance, in Gmail then open the Terminal and type:

nslookup -q=mx gmail.com

"While .. End While" doesn't work in VBA?

VBA is not VB/VB.NET

The correct reference to use is Do..Loop Statement (VBA). Also see the article Excel VBA For, Do While, and Do Until. One way to write this is:

Do While counter < 20
    counter = counter + 1
Loop

(But a For..Next might be more appropriate here.)

Happy coding.

How to turn a vector into a matrix in R?

Just use matrix:

matrix(vec,nrow = 7,ncol = 7)

One advantage of using matrix rather than simply altering the dimension attribute as Gavin points out, is that you can specify whether the matrix is filled by row or column using the byrow argument in matrix.

Skipping Incompatible Libraries at compile

That message isn't actually an error - it's just a warning that the file in question isn't of the right architecture (e.g. 32-bit vs 64-bit, wrong CPU architecture). The linker will keep looking for a library of the right type.

Of course, if you're also getting an error along the lines of can't find lPI-Http then you have a problem :-)

It's hard to suggest what the exact remedy will be without knowing the details of your build system and makefiles, but here are a couple of shots in the dark:

  1. Just to check: usually you would add flags to CFLAGS rather than CTAGS - are you sure this is correct? (What you have may be correct - this will depend on your build system!)
  2. Often the flag needs to be passed to the linker too - so you may also need to modify LDFLAGS

If that doesn't help - can you post the full error output, plus the actual command (e.g. gcc foo.c -m32 -Dxxx etc) that was being executed?

Uncaught TypeError: Cannot read property 'value' of null

I am unsure which of them is wrong because you did not provide your HTML, but one of these does not exist:

var str = document.getElementById("cal_preview").value;
var str1 = document.getElementById("year").value;
var str2 = document.getElementById("holiday").value;
var str3 = document.getElementById("cal_option").value;

There is either no element with the id cal_preview, year, holiday, cal_option, or some combination.

Therefore, JavaScript is unable to read the value of something that does not exist.

EDIT:

If you want to check that the element exists first, you could use an if statement for each:

var str,
element = document.getElementById('cal_preview');
if (element != null) {
    str = element.value;
}
else {
    str = null;
}

You could obviously change the else statement if you want or have no else statement at all, but that is all about preference.

Day Name from Date in JS

Solution No.1

var today = new Date();

  var day = today.getDay();

  var days = ["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"];

  var dayname = days[day];

  document.write(dayname);

Solution No.2

      var today = new Date();

  var day = today.getDay();

  switch(day){
    case 0:
    day = "Sunday";
    break;

    case 1:
    day = "Monday";
    break;

    case 2:
    day ="Tuesday";
    break;

    case 3:
    day = "Wednesday";
    break;

    case 4:
    day = "Thrusday";
    break;

    case 5:
    day = "Friday";
    break;

    case 6:
    day = "Saturday";
    break;
  }


document.write(day);

Convert UTC to local time in Rails 3

There is actually a nice Gem called local_time by basecamp to do all of that on client side only, I believe:

https://github.com/basecamp/local_time

How can I control the speed that bootstrap carousel slides in items?

One thing I noticed is that Bootstrap 3 is adding the styles with both a .6s and 0.6s. So you may need to explicitly define your transition duration like this (CSS)

    .carousel-inner>.item {
    -webkit-transition: 0.9s ease-in-out left;
    transition: 0.9s ease-in-out left;
    -webkit-transition: 0.9s, ease-in-out, left;
    -moz-transition: .9s, ease-in-out, left;
    -o-transition: .9s, ease-in-out, left;
    transition: .9s, ease-in-out, left;
    }

C++ [Error] no matching function for call to

You are trying to call DeckOfCards::shuffle with a deckOfCards parameter:

deckOfCards cardDeck; // create DeckOfCards object
cardDeck.shuffle(cardDeck); // shuffle the cards in the deck

But the method takes a vector<Card>&:

void deckOfCards::shuffle(vector<Card>& deck)

The compiler error messages are quite clear on this. I'll paraphrase the compiler as it talks to you.

Error:

[Error] no matching function for call to 'deckOfCards::shuffle(deckOfCards&)'

Paraphrased:

Hey, pal. You're trying to call a function called shuffle which apparently takes a single parameter of type reference-to-deckOfCards, but there is no such function.

Error:

[Note] candidate is:

In file included from main.cpp

[Note] void deckOfCards::shuffle(std::vector&)

Paraphrased:

I mean, maybe you meant this other function called shuffle, but that one takes a reference-tovector<something>.

Error:

[Note] no known conversion for argument 1 from 'deckOfCards' to 'std::vector&'

Which I'd be happy to call if I knew how to convert from a deckOfCards to a vector; but I don't. So I won't.

What's the @ in front of a string in C#?

Putting a @ in front of a string enables you to use special characters such as a backslash or double-quotes without having to use special codes or escape characters.

So you can write:

string path = @"C:\My path\";

instead of:

string path = "C:\\My path\\";

Gets last digit of a number

Although the best way to do this is to use % if you insist on using strings this will work

public int lastDigit(int number)
{
return Integer.parseInt(String.valueOf(Integer.toString(number).charAt(Integer.toString(number).length() - 1)));
}

but I just wrote this for completeness. Do not use this code. it is just awful.

How to get a value from a Pandas DataFrame and not the index and object type

Use the values attribute to return the values as a np array and then use [0] to get the first value:

In [4]:
df.loc[df.Letters=='C','Letters'].values[0]

Out[4]:
'C'

EDIT

I personally prefer to access the columns using subscript operators:

df.loc[df['Letters'] == 'C', 'Letters'].values[0]

This avoids issues where the column names can have spaces or dashes - which mean that accessing using ..

MySql : Grant read only options?

Note for MySQL 8 it's different

You need to do it in two steps:

CREATE USER 'readonly_user'@'localhost' IDENTIFIED BY 'some_strong_password';
GRANT SELECT, SHOW VIEW ON *.* TO 'readonly_user'@'localhost';
flush privileges;

CSS rotate property in IE

http://css3please.com/

Scroll down to '.box_rotate' for the Microsoft IE9+ prefix. Similar discussion here: Rotating a Div Element in jQuery

CURL and HTTPS, "Cannot resolve host"

I had the same problem. Coudn't resolve google.com. There was a bug somewhere in php fpm, which i am using. Restarting php-fpm solved it for me.

How to remove files from git staging area?

Use "git reset HEAD <file>..." to unstage fils

ex : to unstage all files

git reset HEAD .

to unstage one file

git reset HEAD nameFile.txt

Using PUT method in HTML form

_method hidden field workaround

The following simple technique is used by a few web frameworks:

  • add a hidden _method parameter to any form that is not GET or POST:

    <input type="hidden" name="_method" value="PUT">
    

    This can be done automatically in frameworks through the HTML creation helper method.

  • fix the actual form method to POST (<form method="post")

  • processes _method on the server and do exactly as if that method had been sent instead of the actual POST

You can achieve this in:

  • Rails: form_tag
  • Laravel: @method("PATCH")

Rationale / history of why it is not possible in pure HTML: https://softwareengineering.stackexchange.com/questions/114156/why-there-are-no-put-and-delete-methods-in-html-forms

UITableView - change section header color

In iOS 7.0.4 I created a custom header with it's own XIB. Nothing mentioned here before worked. It had to be the subclass of the UITableViewHeaderFooterView to work with the dequeueReusableHeaderFooterViewWithIdentifier: and it seems that class is very stubborn regarding the background color. So finally I added an UIView (you could do it either with code or IB) with name customBackgroudView, and then set it's backgroundColor property. In layoutSubviews: I set that view's frame to bounds. It work with iOS 7 and gives no glitches.

// in MyTableHeaderView.xib drop an UIView at top of the first child of the owner
// first child becomes contentView

// in MyTableHeaderView.h
@property (nonatomic, weak) IBOutlet UIView * customBackgroundView;

// in MyTableHeaderView.m
-(void)layoutSubviews;
{
    [super layoutSubviews];

    self.customBackgroundView.frame = self.bounds;
}
// if you don't have XIB / use IB, put in the initializer:
-(id)initWithReuseIdentifier:(NSString *)reuseIdentifier
{
    ...
    UIView * customBackgroundView = [[UIView alloc] init];
    [self.contentView addSubview:customBackgroundView];
    _customBackgroundView = customBackgroundView;
    ...
}


// in MyTableViewController.m
-(UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{
    MyTableHeaderView * header = [self.tableView
                                          dequeueReusableHeaderFooterViewWithIdentifier:@"MyTableHeaderView"];
    header.customBackgroundView.backgroundColor = [UIColor redColor];
    return header;
}

RecyclerView - How to smooth scroll to top of item on a certain position?

We can try like this

    recyclerView.getLayoutManager().smoothScrollToPosition(recyclerView,new RecyclerView.State(), recyclerView.getAdapter().getItemCount());

clear data inside text file in c++

If you simply open the file for writing with the truncate-option, you'll delete the content.

std::ofstream ofs;
ofs.open("test.txt", std::ofstream::out | std::ofstream::trunc);
ofs.close();

http://www.cplusplus.com/reference/fstream/ofstream/open/

How to switch a user per task or set of tasks?

In Ansible >1.4 you can actually specify a remote user at the task level which should allow you to login as that user and execute that command without resorting to sudo. If you can't login as that user then the sudo_user solution will work too.

---
- hosts: webservers
  remote_user: root
  tasks:
    - name: test connection
      ping:
      remote_user: yourname

See http://docs.ansible.com/playbooks_intro.html#hosts-and-users

How to center an element in the middle of the browser window?

This is completely possible with just CSS-- no JavaScript needed: Here's an example

Here is the source code behind that example:

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>  
<meta http-equiv="content-type" content="text/html;charset=ISO-8859-1">
<title>Dead Centre</title>  
<style type="text/css" media="screen"><!--
body 
    {
    color: white;
    background-color: #003;
    margin: 0px
    }

#horizon        
    {
    color: white;
    background-color: transparent;
    text-align: center;
    position: absolute;
    top: 50%;
    left: 0px;
    width: 100%;
    height: 1px;
    overflow: visible;
    visibility: visible;
    display: block
    }

#content    
    {
    font-family: Verdana, Geneva, Arial, sans-serif;
    background-color: transparent;
    margin-left: -125px;
    position: absolute;
    top: -35px;
    left: 50%;
    width: 250px;
    height: 70px;
    visibility: visible
    }

.bodytext 
    {
    font-size: 14px
    }

.headline 
    {
    font-weight: bold;
    font-size: 24px
    }

#footer 
    {
    font-size: 11px;
    font-family: Verdana, Geneva, Arial, sans-serif;
    text-align: center;
    position: absolute;
    bottom: 0px;
    left: 0px;
    width: 100%;
    height: 20px;
    visibility: visible;
    display: block
    }

a:link, a:visited 
    {
    color: #06f;
    text-decoration: none
    }

a:hover 
    {
    color: red;
    text-decoration: none
    }

--></style>
</head>
<body>
<div id="horizon">
    <div id="content">
        <div class="bodytext">
        This text is<br>
        <span class="headline">DEAD CENTRE</span><br>
        and stays there!</div>
    </div>
</div>
<div id="footer">
    <a href="http://www.wpdfd.com/editorial/thebox/deadcentre4.html">view construction</a></div>
</body>
</html>

How to convert between bytes and strings in Python 3?

In python3, there is a bytes() method that is in the same format as encode().

str1 = b'hello world'
str2 = bytes("hello world", encoding="UTF-8")
print(str1 == str2) # Returns True

I didn't read anything about this in the docs, but perhaps I wasn't looking in the right place. This way you can explicitly turn strings into byte streams and have it more readable than using encode and decode, and without having to prefex b in front of quotes.

how to add value to a tuple?

    list_of_tuples = [('1', '2', '3', '4'),
                      ('2', '3', '4', '5'),
                      ('3', '4', '5', '6'),
                      ('4', '5', '6', '7')]


    def mod_tuples(list_of_tuples):
        for i in range(0, len(list_of_tuples)):
            addition = ''
            for x in list_of_tuples[i]:
                addition = addition + x
            list_of_tuples[i] = list_of_tuples[i] + (addition,)
        return list_of_tuples

    # check: 
    print mod_tuples(list_of_tuples)

How can I color Python logging output?

Quick and dirty solution for predefined log levels and without defining a new class.

logging.addLevelName( logging.WARNING, "\033[1;31m%s\033[1;0m" % logging.getLevelName(logging.WARNING))
logging.addLevelName( logging.ERROR, "\033[1;41m%s\033[1;0m" % logging.getLevelName(logging.ERROR))

What use is find_package() if you need to specify CMAKE_MODULE_PATH anyway?

You don't need to specify the module path per se. CMake ships with its own set of built-in find_package scripts, and their location is in the default CMAKE_MODULE_PATH.

The more normal use case for dependent projects that have been CMakeified would be to use CMake's external_project command and then include the Use[Project].cmake file from the subproject. If you just need the Find[Project].cmake script, copy it out of the subproject and into your own project's source code, and then you won't need to augment the CMAKE_MODULE_PATH in order to find the subproject at the system level.

Using an HTTP PROXY - Python

You can do it even without the HTTP_PROXY environment variable. Try this sample:

import urllib2

proxy_support = urllib2.ProxyHandler({"http":"http://61.233.25.166:80"})
opener = urllib2.build_opener(proxy_support)
urllib2.install_opener(opener)

html = urllib2.urlopen("http://www.google.com").read()
print html

In your case it really seems that the proxy server is refusing the connection.


Something more to try:

import urllib2

#proxy = "61.233.25.166:80"
proxy = "YOUR_PROXY_GOES_HERE"

proxies = {"http":"http://%s" % proxy}
url = "http://www.google.com/search?q=test"
headers={'User-agent' : 'Mozilla/5.0'}

proxy_support = urllib2.ProxyHandler(proxies)
opener = urllib2.build_opener(proxy_support, urllib2.HTTPHandler(debuglevel=1))
urllib2.install_opener(opener)

req = urllib2.Request(url, None, headers)
html = urllib2.urlopen(req).read()
print html

Edit 2014: This seems to be a popular question / answer. However today I would use third party requests module instead.

For one request just do:

import requests

r = requests.get("http://www.google.com", 
                 proxies={"http": "http://61.233.25.166:80"})
print(r.text)

For multiple requests use Session object so you do not have to add proxies parameter in all your requests:

import requests

s = requests.Session()
s.proxies = {"http": "http://61.233.25.166:80"}

r = s.get("http://www.google.com")
print(r.text)

How to check if running as root in a bash script

Very simple way just put:

if [ "$(whoami)" == "root" ] ; then
    # you are root
else
    # you are not root
fi

The benefit of using this instead of id is that you can check whether a certain non-root user is running the command, too; eg.

if [ "$(whoami)" == "john" ] ; then
    # you are john
else
    # you are not john
fi

How to send image to PHP file using Ajax?

<html>
  <head>
    <script src="http://code.jquery.com/jquery-1.9.1.js"></script>
    <script>
      $(function () {

        $('#abc').on('submit', function (e) {

          e.preventDefault();

          $.ajax({
            url: 'post.php',
            method:'POST',
            data: new FormData(this),
            contentType: false,
            cache:false,
            processData:false,
            success: function (data) {
              alert(data);
              location.reload();
            }
          });

        });

      });
    </script>
  </head>
  <body>
    <form enctype= "multipart/form-data" id="abc">
      <input name="fname" ><br>
      <input name="lname"><br>
      <input type="file" name="file" required=""><br>
      <input name="submit" type="submit" value="Submit">
    </form>
  </body>
</html>

Access mysql remote database from command line

Try this command mysql -uuser -hhostname -PPORT -ppassword.

I faced a similar situation and later when mysql port for host was entered with the command, it was solved.

Is a Python dictionary an example of a hash table?

Yes. Internally it is implemented as open hashing based on a primitive polynomial over Z/2 (source).

Getting random numbers in Java

int max = 50;
int min = 1;

1. Using Math.random()

double random = Math.random() * 49 + 1;
or
int random = (int )(Math.random() * 50 + 1);

This will give you value from 1 to 50 in case of int or 1.0 (inclusive) to 50.0 (exclusive) in case of double

Why?

random() method returns a random number between 0.0 and 0.9..., you multiply it by 50, so upper limit becomes 0.0 to 49.999... when you add 1, it becomes 1.0 to 50.999..., now when you truncate to int, you get 1 to 50. (thanks to @rup in comments). leepoint's awesome write-up on both the approaches.

2. Using Random class in Java.

Random rand = new Random(); 
int value = rand.nextInt(50); 

This will give value from 0 to 49.

For 1 to 50: rand.nextInt((max - min) + 1) + min;

Source of some Java Random awesomeness.

How to connect to MySQL Database?

 private void Initialize()
    {
        server = "localhost";
        database = "connectcsharptomysql";
        uid = "username";
        password = "password";
        string connectionString;
        connectionString = "SERVER=" + server + ";" + "DATABASE=" + 
        database + ";" + "U`enter code here`ID=" + uid + ";" + "PASSWORD=" + password + ";";

        connection = new MySqlConnection(connectionString);
    }

Difference between CLOB and BLOB from DB2 and Oracle Perspective?

BLOB is for binary data (videos, images, documents, other)

CLOB is for large text data (text)

Maximum size on MySQL 2GB

Maximum size on Oracle 128TB

Asp.net Hyperlink control equivalent to <a href="#"></a>

hyperlink1.NavigateUrl = "#"; or
hyperlink1.attributes["href"] = "#"; or
<asp:HyperLink NavigateUrl="#" runat="server" />

MySQL JOIN the most recent row only?

It's a good idea that logging actual data into "customer_data" table. With this data you can select all data from "customer_data" table as you wish.

how to check which version of nltk, scikit learn installed?

For checking the version of scikit-learn in shell script, if you have pip installed, you can try this command

pip freeze | grep scikit-learn
scikit-learn==0.17.1

Hope it helps!

background-image: url("images/plaid.jpg") no-repeat; wont show up

Most important

Keep in mind that relative URLs are resolved from the URL of your stylesheet.

So it will work if folder images is inside the stylesheets folder.

From you description you would need to change it to either

url("../images/plaid.jpg")

or

url("/images/plaid.jpg") 

Additional 1

Also you cannot have no selector..

CSS is applied through selectors..


Additional 2

You should use either the shorthand background to pass multiple values like this

background: url("../images/plaid.jpg") no-repeat;

or the verbose syntax of specifying each property on its own

background-image: url("../images/plaid.jpg");
background-repeat:no-repeat;

LabelEncoder: TypeError: '>' not supported between instances of 'float' and 'str'

This is due to the series df[cat] containing elements that have varying data types e.g.(strings and/or floats). This could be due to the way the data is read, i.e. numbers are read as float and text as strings or the datatype was float and changed after the fillna operation.

In other words

pandas data type 'Object' indicates mixed types rather than str type

so using the following line:

df[cat] = le.fit_transform(df[cat].astype(str))


should help

How do I change the IntelliJ IDEA default JDK?

To change the JDK version of the Intellij-IDE himself:

Start the IDE -> Help -> Find Action

than type:

Switch Boot JDK

or (depend on your version)

Switch IDE boot JDK

How do I see which checkbox is checked?

Try this

index.html

<form action="form.php" method="post">
    Do you like stackoverflow?
    <input type="checkbox" name="like" value="Yes" />  
    <input type="submit" name="formSubmit" value="Submit" /> 
</form>

form.php

<html>
<head>
</head>
<body>

<?php
    if(isset($_POST['like']))
    {
        echo "<h1>You like Stackoverflow.<h1>";
    }
    else
    {
        echo "<h1>You don't like Stackoverflow.</h1>";
    }   
?>

</body>
</html>

Or this

<?php
    if(isset($_POST['like'])) && 
    $_POST['like'] == 'Yes') 
    {
        echo "You like Stackoverflow.";
    }
    else
    {
        echo "You don't like Stackoverflow.";
    }   
?>

Node.js create folder or use existing

You can do all of this with the File System module.

const
  fs = require('fs'),
  dirPath = `path/to/dir`

// Check if directory exists.
fs.access(dirPath, fs.constants.F_OK, (err)=>{
  if (err){
    // Create directory if directory does not exist.
    fs.mkdir(dirPath, {recursive:true}, (err)=>{
      if (err) console.log(`Error creating directory: ${err}`)
      else console.log('Directory created successfully.')
    })
  }
  // Directory now exists.
})

You really don't even need to check if the directory exists. The following code also guarantees that the directory either already exists or is created.

const
  fs = require('fs'),
  dirPath = `path/to/dir`

// Create directory if directory does not exist.
fs.mkdir(dirPath, {recursive:true}, (err)=>{
  if (err) console.log(`Error creating directory: ${err}`)
  // Directory now exists.
})

Pass props in Link react-router

After install react-router-dom

<Link
    to={{
      pathname: "/product-detail",
      productdetailProps: {
       productdetail: "I M passed From Props"
      }
   }}>
    Click To Pass Props
</Link>

and other end where the route is redirected do this

componentDidMount() {
            console.log("product props is", this.props.location.productdetailProps);
          }

what is this value means 1.845E-07 in excel?

Highlight the cells, format cells, select Custom then select zero.

What does "export default" do in JSX?

Simplest Understanding for default export is

Export is ES6's feature which is used to Export a module(file) and use it in some other module(file).

Default Export:

  1. default export is the convention if you want to export only one object(variable, function, class) from the file(module).
  2. There could be only one default export per file, but not restricted to only one export.
  3. When importing default exported object we can rename it as well.

Export or Named Export:

  1. It is used to export the object(variable, function, calss) with the same name.

  2. It is used to export multiple objects from one file.

  3. It cannot be renamed when importing in another file, it must have the same name that was used to export it, but we can create its alias by using as operator.

In React, Vue and many other frameworks the Export is mostly used to export reusable components to make modular based applications.

String to HashMap JAVA

USING JAVA 8:

Map<String, String> headerMap = Arrays.stream(header.split(","))
                    .map(s -> s.split(":"))
                    .collect(Collectors.toMap(s -> s[0], s -> s[1]));

Java Compare Two List's object values?

See if this works.

import java.util.ArrayList;
import java.util.List;


public class ArrayListComparison {

    public static void main(String[] args) {
        List<MyData> list1 = new ArrayList<MyData>();
        list1.add(new MyData("Ram", true));
        list1.add(new MyData("Hariom", true));
        list1.add(new MyData("Shiv", true));
//      list1.add(new MyData("Shiv", false));
        List<MyData> list2 = new ArrayList<MyData>();
        list2.add(new MyData("Ram", true));
        list2.add(new MyData("Hariom", true));
        list2.add(new MyData("Shiv", true));

        System.out.println("Lists are equal:" + listEquals(list1, list2));
    }

    private static boolean listEquals(List<MyData> list1, List<MyData> list2) {
        if(list1.size() != list2.size())
            return true;
        for (MyData myData : list1) {
            if(!list2.contains(myData))
                return true;
        }
        return false;
    }
}

class MyData{
    String name;
    boolean check;


    public MyData(String name, boolean check) {
        super();
        this.name = name;
        this.check = check;
    }
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + (check ? 1231 : 1237);
        result = prime * result + ((name == null) ? 0 : name.hashCode());
        return result;
    }
    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        MyData other = (MyData) obj;
        if (check != other.check)
            return false;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }
} 

Difference between two lists

List<ObjectC> _list_DF_BW_ANB = new List<ObjectC>();    
List<ObjectA> _listA = new List<ObjectA>();
List<ObjectB> _listB = new List<ObjectB>();

foreach (var itemB in _listB )
{     
    var flat = 0;
    foreach(var itemA in _listA )
    {
        if(itemA.ProductId==itemB.ProductId)
        {
            flat = 1;
            break;
        }
    }
    if (flat == 0)
    {
        _list_DF_BW_ANB.Add(itemB);
    }
}

How to move or copy files listed by 'find' command in unix?

If you're using GNU find,

find . -mtime 1 -exec cp -t ~/test/ {} +

This works as well as piping the output into xargs while avoiding the pitfalls of doing so (it handles embedded spaces and newlines without having to use find ... -print0 | xargs -0 ...).

Force encode from US-ASCII to UTF-8 (iconv)

There is no difference between US ASCII and UTF-8, so there isn't any need to reconvert it.

But here a little hint, if you have trouble with special-chars while recoding.

Add //TRANSLIT after the source-charset-Parameter.

Example:

iconv -f ISO-8859-1//TRANSLIT -t UTF-8 filename.sql > utf8-filename.sql

This helps me with strange types of quotes, which are always breaking the character set reencode process.

The developers of this app have not set up this app properly for Facebook Login?

This error also occurs when you try to log in in your test version of the Facebook app and you have not added the user you are trying to test the log in with in the Roles -> Testers section.

To fix it, just add the email address of the Facebook account you are trying to log in with in the section above.

Finally, make sure the user you added accepts the request sent before you try to test otherwise the log in process will fail in the second screen just after the user accept the conditions.

Meaning of "[: too many arguments" error from if [] (square brackets)

Just bumped into this post, by getting the same error, trying to test if two variables are both empty (or non-empty). That turns out to be a compound comparison - 7.3. Other Comparison Operators - Advanced Bash-Scripting Guide; and I thought I should note the following:

  • I used -e thinking it means "empty" at first; but that means "file exists" - use -z for testing empty variable (string)
  • String variables need to be quoted
  • For compound logical AND comparison, either:
    • use two tests and && them: [ ... ] && [ ... ]
    • or use the -a operator in a single test: [ ... -a ... ]

Here is a working command (searching through all txt files in a directory, and dumping those that grep finds contain both of two words):

find /usr/share/doc -name '*.txt' | while read file; do \
  a1=$(grep -H "description" $file); \
  a2=$(grep -H "changes" $file); \
  [ ! -z "$a1" -a ! -z "$a2"  ] && echo -e "$a1 \n $a2" ; \
done

Edit 12 Aug 2013: related problem note:

Note that when checking string equality with classic test (single square bracket [), you MUST have a space between the "is equal" operator, which in this case is a single "equals" = sign (although two equals' signs == seem to be accepted as equality operator too). Thus, this fails (silently):

$ if [ "1"=="" ] ; then echo A; else echo B; fi 
A
$ if [ "1"="" ] ; then echo A; else echo B; fi 
A
$ if [ "1"="" ] && [ "1"="1" ] ; then echo A; else echo B; fi 
A
$ if [ "1"=="" ] && [ "1"=="1" ] ; then echo A; else echo B; fi 
A

... but add the space - and all looks good:

$ if [ "1" = "" ] ; then echo A; else echo B; fi 
B
$ if [ "1" == "" ] ; then echo A; else echo B; fi 
B
$ if [ "1" = "" -a "1" = "1" ] ; then echo A; else echo B; fi 
B
$ if [ "1" == "" -a "1" == "1" ] ; then echo A; else echo B; fi 
B

How to cast an Object to an int

so divide1=me.getValue()/2;

int divide1 = (Integer) me.getValue()/2;

How to execute UNION without sorting? (SQL)

select T.Col1, T.Col2, T.Sort
from 
    (
      select T.Col1,
             T.Col2,
             T.Sort,
             rank() over(partition by T.Col1, T.Col2 order by T.Sort) as rn
      from
          (
            select Col1, Col2, 1 as Sort
            from Table1
            union all
            select Col1, Col2, 2
            from Table2
          ) as T
    ) as T
where T.rn = 1    
order by T.Sort

Pretty graphs and charts in Python

You didn't mention what output format you need but reportlab is good at creating charts both in pdf and bitmap (e.g. png) format.

Here is a simple example of a barchart in png and pdf format:

from reportlab.graphics.shapes import Drawing
from reportlab.graphics.charts.barcharts import VerticalBarChart

d = Drawing(300, 200)

chart = VerticalBarChart()
chart.width = 260
chart.height = 160
chart.x = 20
chart.y = 20
chart.data = [[1,2], [3,4]]
chart.categoryAxis.categoryNames = ['foo', 'bar']
chart.valueAxis.valueMin = 0

d.add(chart)
d.save(fnRoot='test', formats=['png', 'pdf'])

alt text http://i40.tinypic.com/2j677tl.jpg

Note: the image has been converted to jpg by the image host.

Disable PHP in directory (including all sub-directories) with .htaccess

None of those answers are working for me (either generating a 500 error or doing nothing). That is probably due to the fact that I'm working on a hosted server where I can't have access to Apache configuration.

But this worked for me :

RewriteRule ^.*\.php$ - [F,L]

This line will generate a 403 Forbidden error for any URL that ends with .php and ends up in this subdirectory.

@Oussama lead me to the right direction here, thanks to him.

Assign null to a SqlParameter

I use a simple method with a null check.

    public SqlParameter GetNullableParameter(string parameterName, object value)
    {
        if (value != null)
        {
            return new SqlParameter(parameterName, value);
        }
        else
        {
            return new SqlParameter(parameterName, DBNull.Value);
        }
    }

Why can't decimal numbers be represented exactly in binary?

This is a good question.

All your question is based on "how do we represent a number?"

ALL the numbers can be represented with decimal representation or with binary (2's complement) representation. All of them !!

BUT some (most of them) require infinite number of elements ("0" or "1" for the binary position, or "0", "1" to "9" for the decimal representation).

Like 1/3 in decimal representation (1/3 = 0.3333333... <- with an infinite number of "3")

Like 0.1 in binary ( 0.1 = 0.00011001100110011.... <- with an infinite number of "0011")

Everything is in that concept. Since your computer can only consider finite set of digits (decimal or binary), only some numbers can be exactly represented in your computer...

And as said Jon, 3 is a prime number which isn't a factor of 10, so 1/3 cannot be represented with a finite number of elements in base 10.

Even with arithmetic with arbitrary precision, the numbering position system in base 2 is not able to fully describe 6.1, although it can represent 61.

For 6.1, we must use another representation (like decimal representation, or IEEE 854 that allows base 2 or base 10 for the representation of floating-point values)

Adding image inside table cell in HTML

You have referenced the image as a path on your computer (C:\etc\etc)......is it located there? You didn't answer what others have asked. I have taken your code, placed it in dreamweaver and it works apart from the image as I don't have that stored.

Check the location and then let us know.

How to prevent caching of my Javascript file?

You can add a random (or datetime string) as query string to the url that points to your script. Like so:

<script type="text/javascript" src="test.js?q=123"></script> 

Every time you refresh the page you need to make sure the value of 'q' is changed.

Use jQuery to change an HTML tag?

Here's an extension that will do it all, on as many elements in as many ways...

Example usage:

keep existing class and attributes:

$('div#change').replaceTag('<span>', true);

or

Discard existing class and attributes:

$('div#change').replaceTag('<span class=newclass>', false);

or even

replace all divs with spans, copy classes and attributes, add extra class name

$('div').replaceTag($('<span>').addClass('wasDiv'), true);

Plugin Source:

$.extend({
    replaceTag: function (currentElem, newTagObj, keepProps) {
        var $currentElem = $(currentElem);
        var i, $newTag = $(newTagObj).clone();
        if (keepProps) {//{{{
            newTag = $newTag[0];
            newTag.className = currentElem.className;
            $.extend(newTag.classList, currentElem.classList);
            $.extend(newTag.attributes, currentElem.attributes);
        }//}}}
        $currentElem.wrapAll($newTag);
        $currentElem.contents().unwrap();
        // return node; (Error spotted by Frank van Luijn)
        return this; // Suggested by ColeLawrence
    }
});

$.fn.extend({
    replaceTag: function (newTagObj, keepProps) {
        // "return" suggested by ColeLawrence
        return this.each(function() {
            jQuery.replaceTag(this, newTagObj, keepProps);
        });
    }
});

How do I get multiple subplots in matplotlib?

Go with the following if you really want to use a loop. Nobody has actually answered how to feed data in a loop:

def plot(data):
    fig = plt.figure(figsize=(100, 100))
    for idx, k in enumerate(data.keys(), 1):
        x, y = data[k].keys(), data[k].values
        plt.subplot(63, 10, idx)
        plt.bar(x, y)  
    plt.show()

Start thread with member function

Some users have already given their answer and explained it very well.

I would like to add few more things related to thread.

  1. How to work with functor and thread. Please refer to below example.

  2. The thread will make its own copy of the object while passing the object.

    #include<thread>
    #include<Windows.h>
    #include<iostream>
    
    using namespace std;
    
    class CB
    {
    
    public:
        CB()
        {
            cout << "this=" << this << endl;
        }
        void operator()();
    };
    
    void CB::operator()()
    {
        cout << "this=" << this << endl;
        for (int i = 0; i < 5; i++)
        {
            cout << "CB()=" << i << endl;
            Sleep(1000);
        }
    }
    
    void main()
    {
        CB obj;     // please note the address of obj.
    
        thread t(obj); // here obj will be passed by value 
                       //i.e. thread will make it own local copy of it.
                        // we can confirm it by matching the address of
                        //object printed in the constructor
                        // and address of the obj printed in the function
    
        t.join();
    }
    

Another way of achieving the same thing is like:

void main()
{
    thread t((CB()));

    t.join();
}

But if you want to pass the object by reference then use the below syntax:

void main()
{
    CB obj;
    //thread t(obj);
    thread t(std::ref(obj));
    t.join();
}

how can I set visible back to true in jquery

Remove the visible="false" attribute and add a CSS class that is not visible by default. Then you should be able to reference the dropdown by the correct id, for example:

$("#ctl00_cphTest_test1").show();

Above ID you should serach for in the source of the rendered page in your browser.

How to add a filter class in Spring Boot?

First, add @ServletComponentScan to your SpringBootApplication class.

@ServletComponentScan
public class Application {

Second, create a filter file extending Filter or third-party filter class and add @WebFilter to this file like this:

@Order(1) //optional
@WebFilter(filterName = "XXXFilter", urlPatterns = "/*",
    dispatcherTypes = {DispatcherType.REQUEST, DispatcherType.FORWARD},
    initParams = {@WebInitParam(name = "confPath", value = "classpath:/xxx.xml")})
public class XXXFilter extends Filter{

Bootstrap 3.0 Sliding Menu from left

Probably late but here is a plugin that can do the job : http://multi-level-push-menu.make.rs/

Also v2 can use mobile gesture such as swipe ;)

What is a elegant way in Ruby to tell if a variable is a Hash or an Array?

First of all, the best answer for the literal question is

Hash === @some_var

But the question really should have been answered by showing how to do duck-typing here. That depends a bit on what kind of duck you need.

@some_var.respond_to?(:each_pair)

or

@some_var.respond_to?(:has_key?)

or even

@some_var.respond_to?(:to_hash)

may be right depending on the application.

java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.Integer in java 1.6

The number of results can (theoretically) be greater than the range of an integer. I would refactor the code and work with the returned long value instead.

Where to find free public Web Services?

https://www.programmableweb.com/ -- Great collection of all category API's across web. It not only show cases the API's , but also Developers who use those API's in their applications and code samples, rating of the API and much more. They have more than apis they also have sdk and libraries too.

What is the use of System.in.read()?

system.in.read() method reads a byte and returns as an integer but if you enter a no between 1 to 9 ,it will return 48+ values because in ascii code table ,ascii values of 1-9 are 48-57 . hope , it will help.

How to print a double with two decimals in Android?

Before you use DecimalFormat you need to use the following import or your code will not work:

import java.text.DecimalFormat;

The code for formatting is:

DecimalFormat precision = new DecimalFormat("0.00"); 
// dblVariable is a number variable and not a String in this case
txtTextField.setText(precision.format(dblVariable));

Getting current unixtimestamp using Moment.js

For anyone who finds this page looking for unix timestamp w/ milliseconds, the documentation says

moment().valueOf()

or

+moment();

you can also get it through moment().format('x') (or .format('X') [capital X] for unix seconds with decimal milliseconds), but that will give you a string. Which moment.js won't actually parse back afterwards, unless you convert/cast it back to a number first.

How do I make JavaScript beep?

This will enable you to play the sound multiple times, in contrast to the top-voted answer:

var playSound = (function beep() {
    var snd = new Audio("data:audio/wav;base64,//uQRAAAAWMSLwUIYAAsYkXgoQwAEaYLWfkWgAI0wWs/ItAAAGDgYtAgAyN+QWaAAihwMWm4G8QQRDiMcCBcH3Cc+CDv/7xA4Tvh9Rz/y8QADBwMWgQAZG/ILNAARQ4GLTcDeIIIhxGOBAuD7hOfBB3/94gcJ3w+o5/5eIAIAAAVwWgQAVQ2ORaIQwEMAJiDg95G4nQL7mQVWI6GwRcfsZAcsKkJvxgxEjzFUgfHoSQ9Qq7KNwqHwuB13MA4a1q/DmBrHgPcmjiGoh//EwC5nGPEmS4RcfkVKOhJf+WOgoxJclFz3kgn//dBA+ya1GhurNn8zb//9NNutNuhz31f////9vt///z+IdAEAAAK4LQIAKobHItEIYCGAExBwe8jcToF9zIKrEdDYIuP2MgOWFSE34wYiR5iqQPj0JIeoVdlG4VD4XA67mAcNa1fhzA1jwHuTRxDUQ//iYBczjHiTJcIuPyKlHQkv/LHQUYkuSi57yQT//uggfZNajQ3Vmz+Zt//+mm3Wm3Q576v////+32///5/EOgAAADVghQAAAAA//uQZAUAB1WI0PZugAAAAAoQwAAAEk3nRd2qAAAAACiDgAAAAAAABCqEEQRLCgwpBGMlJkIz8jKhGvj4k6jzRnqasNKIeoh5gI7BJaC1A1AoNBjJgbyApVS4IDlZgDU5WUAxEKDNmmALHzZp0Fkz1FMTmGFl1FMEyodIavcCAUHDWrKAIA4aa2oCgILEBupZgHvAhEBcZ6joQBxS76AgccrFlczBvKLC0QI2cBoCFvfTDAo7eoOQInqDPBtvrDEZBNYN5xwNwxQRfw8ZQ5wQVLvO8OYU+mHvFLlDh05Mdg7BT6YrRPpCBznMB2r//xKJjyyOh+cImr2/4doscwD6neZjuZR4AgAABYAAAABy1xcdQtxYBYYZdifkUDgzzXaXn98Z0oi9ILU5mBjFANmRwlVJ3/6jYDAmxaiDG3/6xjQQCCKkRb/6kg/wW+kSJ5//rLobkLSiKmqP/0ikJuDaSaSf/6JiLYLEYnW/+kXg1WRVJL/9EmQ1YZIsv/6Qzwy5qk7/+tEU0nkls3/zIUMPKNX/6yZLf+kFgAfgGyLFAUwY//uQZAUABcd5UiNPVXAAAApAAAAAE0VZQKw9ISAAACgAAAAAVQIygIElVrFkBS+Jhi+EAuu+lKAkYUEIsmEAEoMeDmCETMvfSHTGkF5RWH7kz/ESHWPAq/kcCRhqBtMdokPdM7vil7RG98A2sc7zO6ZvTdM7pmOUAZTnJW+NXxqmd41dqJ6mLTXxrPpnV8avaIf5SvL7pndPvPpndJR9Kuu8fePvuiuhorgWjp7Mf/PRjxcFCPDkW31srioCExivv9lcwKEaHsf/7ow2Fl1T/9RkXgEhYElAoCLFtMArxwivDJJ+bR1HTKJdlEoTELCIqgEwVGSQ+hIm0NbK8WXcTEI0UPoa2NbG4y2K00JEWbZavJXkYaqo9CRHS55FcZTjKEk3NKoCYUnSQ0rWxrZbFKbKIhOKPZe1cJKzZSaQrIyULHDZmV5K4xySsDRKWOruanGtjLJXFEmwaIbDLX0hIPBUQPVFVkQkDoUNfSoDgQGKPekoxeGzA4DUvnn4bxzcZrtJyipKfPNy5w+9lnXwgqsiyHNeSVpemw4bWb9psYeq//uQZBoABQt4yMVxYAIAAAkQoAAAHvYpL5m6AAgAACXDAAAAD59jblTirQe9upFsmZbpMudy7Lz1X1DYsxOOSWpfPqNX2WqktK0DMvuGwlbNj44TleLPQ+Gsfb+GOWOKJoIrWb3cIMeeON6lz2umTqMXV8Mj30yWPpjoSa9ujK8SyeJP5y5mOW1D6hvLepeveEAEDo0mgCRClOEgANv3B9a6fikgUSu/DmAMATrGx7nng5p5iimPNZsfQLYB2sDLIkzRKZOHGAaUyDcpFBSLG9MCQALgAIgQs2YunOszLSAyQYPVC2YdGGeHD2dTdJk1pAHGAWDjnkcLKFymS3RQZTInzySoBwMG0QueC3gMsCEYxUqlrcxK6k1LQQcsmyYeQPdC2YfuGPASCBkcVMQQqpVJshui1tkXQJQV0OXGAZMXSOEEBRirXbVRQW7ugq7IM7rPWSZyDlM3IuNEkxzCOJ0ny2ThNkyRai1b6ev//3dzNGzNb//4uAvHT5sURcZCFcuKLhOFs8mLAAEAt4UWAAIABAAAAAB4qbHo0tIjVkUU//uQZAwABfSFz3ZqQAAAAAngwAAAE1HjMp2qAAAAACZDgAAAD5UkTE1UgZEUExqYynN1qZvqIOREEFmBcJQkwdxiFtw0qEOkGYfRDifBui9MQg4QAHAqWtAWHoCxu1Yf4VfWLPIM2mHDFsbQEVGwyqQoQcwnfHeIkNt9YnkiaS1oizycqJrx4KOQjahZxWbcZgztj2c49nKmkId44S71j0c8eV9yDK6uPRzx5X18eDvjvQ6yKo9ZSS6l//8elePK/Lf//IInrOF/FvDoADYAGBMGb7FtErm5MXMlmPAJQVgWta7Zx2go+8xJ0UiCb8LHHdftWyLJE0QIAIsI+UbXu67dZMjmgDGCGl1H+vpF4NSDckSIkk7Vd+sxEhBQMRU8j/12UIRhzSaUdQ+rQU5kGeFxm+hb1oh6pWWmv3uvmReDl0UnvtapVaIzo1jZbf/pD6ElLqSX+rUmOQNpJFa/r+sa4e/pBlAABoAAAAA3CUgShLdGIxsY7AUABPRrgCABdDuQ5GC7DqPQCgbbJUAoRSUj+NIEig0YfyWUho1VBBBA//uQZB4ABZx5zfMakeAAAAmwAAAAF5F3P0w9GtAAACfAAAAAwLhMDmAYWMgVEG1U0FIGCBgXBXAtfMH10000EEEEEECUBYln03TTTdNBDZopopYvrTTdNa325mImNg3TTPV9q3pmY0xoO6bv3r00y+IDGid/9aaaZTGMuj9mpu9Mpio1dXrr5HERTZSmqU36A3CumzN/9Robv/Xx4v9ijkSRSNLQhAWumap82WRSBUqXStV/YcS+XVLnSS+WLDroqArFkMEsAS+eWmrUzrO0oEmE40RlMZ5+ODIkAyKAGUwZ3mVKmcamcJnMW26MRPgUw6j+LkhyHGVGYjSUUKNpuJUQoOIAyDvEyG8S5yfK6dhZc0Tx1KI/gviKL6qvvFs1+bWtaz58uUNnryq6kt5RzOCkPWlVqVX2a/EEBUdU1KrXLf40GoiiFXK///qpoiDXrOgqDR38JB0bw7SoL+ZB9o1RCkQjQ2CBYZKd/+VJxZRRZlqSkKiws0WFxUyCwsKiMy7hUVFhIaCrNQsKkTIsLivwKKigsj8XYlwt/WKi2N4d//uQRCSAAjURNIHpMZBGYiaQPSYyAAABLAAAAAAAACWAAAAApUF/Mg+0aohSIRobBAsMlO//Kk4soosy1JSFRYWaLC4qZBYWFRGZdwqKiwkNBVmoWFSJkWFxX4FFRQWR+LsS4W/rFRb/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////VEFHAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAU291bmRib3kuZGUAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAMjAwNGh0dHA6Ly93d3cuc291bmRib3kuZGUAAAAAAAAAACU=");  
    return function() {     
        snd.play(); 
    }
})();

playSound(); // Play first time
playSound(); // Play second time

CASE (Contains) rather than equal statement

CASE WHEN ', ' + dbo.Table.Column +',' LIKE '%, lactulose,%' 
  THEN 'BP Medication' ELSE '' END AS [BP Medication]

The leading ', ' and trailing ',' are added so that you can handle the match regardless of where it is in the string (first entry, last entry, or anywhere in between).

That said, why are you storing data you want to search on as a comma-separated string? This violates all kinds of forms and best practices. You should consider normalizing your schema.

In addition: don't use 'single quotes' as identifier delimiters; this syntax is deprecated. Use [square brackets] (preferred) or "double quotes" if you must. See "string literals as column aliases" here: http://msdn.microsoft.com/en-us/library/bb510662%28SQL.100%29.aspx

EDIT If you have multiple values, you can do this (you can't short-hand this with the other CASE syntax variant or by using something like IN()):

CASE 
  WHEN ', ' + dbo.Table.Column +',' LIKE '%, lactulose,%' 
  WHEN ', ' + dbo.Table.Column +',' LIKE '%, amlodipine,%' 
  THEN 'BP Medication' ELSE '' END AS [BP Medication]

If you have more values, it might be worthwhile to use a split function, e.g.

USE tempdb;
GO

CREATE FUNCTION dbo.SplitStrings(@List NVARCHAR(MAX))
RETURNS TABLE
AS
   RETURN ( SELECT DISTINCT Item FROM
       ( SELECT Item = x.i.value('(./text())[1]', 'nvarchar(max)')
         FROM ( SELECT [XML] = CONVERT(XML, '<i>'
         + REPLACE(@List,',', '</i><i>') + '</i>').query('.')
           ) AS a CROSS APPLY [XML].nodes('i') AS x(i) ) AS y
       WHERE Item IS NOT NULL
   );
GO

CREATE TABLE dbo.[Table](ID INT, [Column] VARCHAR(255));
GO

INSERT dbo.[Table] VALUES
(1,'lactulose, Lasix (furosemide), oxazepam, propranolol, rabeprazole, sertraline,'),
(2,'lactulite, Lasix (furosemide), lactulose, propranolol, rabeprazole, sertraline,'),
(3,'lactulite, Lasix (furosemide), oxazepam, propranolol, rabeprazole, sertraline,'),
(4,'lactulite, Lasix (furosemide), lactulose, amlodipine, rabeprazole, sertraline,');

SELECT t.ID
  FROM dbo.[Table] AS t
  INNER JOIN dbo.SplitStrings('lactulose,amlodipine') AS s
  ON ', ' + t.[Column] + ',' LIKE '%, ' + s.Item + ',%'
  GROUP BY t.ID;
GO

Results:

ID
----
1
2
4

How to query for Xml values and attributes from table in SQL Server?

Actually you're close to your goal, you just need to use nodes() method to split your rows and then get values:

select
    s.SqmId,
    m.c.value('@id', 'varchar(max)') as id,
    m.c.value('@type', 'varchar(max)') as type,
    m.c.value('@unit', 'varchar(max)') as unit,
    m.c.value('@sum', 'varchar(max)') as [sum],
    m.c.value('@count', 'varchar(max)') as [count],
    m.c.value('@minValue', 'varchar(max)') as minValue,
    m.c.value('@maxValue', 'varchar(max)') as maxValue,
    m.c.value('.', 'nvarchar(max)') as Value,
    m.c.value('(text())[1]', 'nvarchar(max)') as Value2
from sqm as s
    outer apply s.data.nodes('Sqm/Metrics/Metric') as m(c)

sql fiddle demo

Text in a flex container doesn't wrap in IE11

Me too I encountered this issue.

The only alternative is to define a width (or max-width) in the child elements. IE 11 is a bit stupid, and me I just spent 20 minutes to realize this solution.

.parent {
  display: flex;
  flex-direction: column;
  width: 800px;
  border: 1px solid red;
  align-items: center;
}
.child {
  border: 1px solid blue;
  max-width: 800px;
  @media (max-width:960px){ // <--- Here we go. The text won't wrap ? we will make it break !
    max-width: 600px;
  }
  @media (max-width:600px){
    max-width: 400px;
  }
  @media (max-width:400px){
    max-width: 150px;
  }
}

<div class="parent">
  <div class="child">
    Lorem Ipsum is simply dummy text of the printing and typesetting industry
  </div>
  <div class="child">
    Lorem Ipsum is simply dummy text of the printing and typesetting industry
  </div>
</div>

How to fill OpenCV image with one solid color?

Use numpy.full. Here's a Python that creates a gray, blue, green and red image and shows in a 2x2 grid.

import cv2
import numpy as np

gray_img = np.full((100, 100, 3), 127, np.uint8)

blue_img = np.full((100, 100, 3), 0, np.uint8)
green_img = np.full((100, 100, 3), 0, np.uint8)
red_img = np.full((100, 100, 3), 0, np.uint8)

full_layer = np.full((100, 100), 255, np.uint8)

# OpenCV goes in blue, green, red order
blue_img[:, :, 0] = full_layer
green_img[:, :, 1] = full_layer
red_img[:, :, 2] = full_layer

cv2.imshow('2x2_grid', np.vstack([
    np.hstack([gray_img, blue_img]), 
    np.hstack([green_img, red_img])
]))
cv2.waitKey(0)
cv2.destroyWindow('2x2_grid')

Current date without time

it should be as simple as

DateTime.Today

How do I change TextView Value inside Java Code?

I presume that this question is a continuation of this one.

What are you trying to do? Do you really want to dynamically change the text in your TextView objects when the user clicks a button? You can certainly do that, if you have a reason, but, if the text is static, it is usually set in the main.xml file, like this:

<TextView  
android:id="@+id/rate"
android:layout_width="fill_parent" 
android:layout_height="wrap_content" 
android:text="@string/rate"
/>

The string "@string/rate" refers to an entry in your strings.xml file that looks like this:

<string name="rate">Rate</string>

If you really want to change this text later, you can do so by using Nikolay's example - you'd get a reference to the TextView by utilizing the id defined for it within main.xml, like this:


final TextView textViewToChange = (TextView) findViewById(R.id.rate);
textViewToChange.setText(
    "The new text that I'd like to display now that the user has pushed a button.");

how to set textbox value in jquery

I would like to point out to you that .val() also works with selects to select the current selected value.

Passing command line arguments in Visual Studio 2010?

  1. Right click on Project Name.
  2. Select Properties and click.
  3. Then, select Debugging and provide your enough argument into Command Arguments box.

Note:

  • Also, check Configuration type and Platform.

img

After that, Click Apply and OK.

How to decompile an APK or DEX file on Android platform?

http://www.decompileandroid.com/

This website will decompile the code embedded in APK files and extract all the other assets in the file.

Using Mysql WHERE IN clause in codeigniter

Try this one:

$this->db->select("*");
$this->db->where_in("(SELECT trans_id FROM myTable WHERE code = 'B')");
$this->db->where('code !=', 'B');
$this->db->get('myTable');

Note: $this->db->select("*"); is optional when you are selecting all columns from table

What does it mean when MySQL is in the state "Sending data"?

This is quite a misleading status. It should be called "reading and filtering data".

This means that MySQL has some data stored on the disk (or in memory) which is yet to be read and sent over. It may be the table itself, an index, a temporary table, a sorted output etc.

If you have a 1M records table (without an index) of which you need only one record, MySQL will still output the status as "sending data" while scanning the table, despite the fact it has not sent anything yet.

Disable sorting on last column when using jQuery DataTables

use this link http://datatables.net/ref#bSortable

$(document).ready( function() {
   $('#example').dataTable( {
      "aoColumnDefs": [{ "bSortable": false, "aTargets": [ 0 ] }]
    } );
} );

Is it better to return null or empty collection?

From the Framework Design Guidelines 2nd Edition (pg. 256):

DO NOT return null values from collection properties or from methods returning collections. Return an empty collection or an empty array instead.

Here's another interesting article on the benefits of not returning nulls (I was trying to find something on Brad Abram's blog, and he linked to the article).

Edit- as Eric Lippert has now commented to the original question, I'd also like to link to his excellent article.

How to pass parameter to click event in Jquery

You don't need to pass the parameter, you can get it using .attr() method

$(function(){
    $('elements-to-match').click(function(){
        alert("The id is "+ $(this).attr("id") );
    });
});

Access Https Rest Service using Spring RestTemplate

Here is what I ended up with for the similar problem. The idea is the same as in @Avi's answer, but I also wanted to avoid the static "System.setProperty("https.protocols", "TLSv1");", so that any adjustments won't affect the system. Inspired by an answer from here http://www.coderanch.com/t/637177/Security/Disabling-handshake-message-Java

public class MyCustomClientHttpRequestFactory extends SimpleClientHttpRequestFactory {

@Override
protected void prepareConnection(HttpURLConnection connection, String httpMethod) {
    try {
        if (!(connection instanceof HttpsURLConnection)) {
            throw new RuntimeException("An instance of HttpsURLConnection is expected");
        }

        HttpsURLConnection httpsConnection = (HttpsURLConnection) connection;

        TrustManager[] trustAllCerts = new TrustManager[]{
                new X509TrustManager() {
                    public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                        return null;
                    }

                    public void checkClientTrusted(X509Certificate[] certs, String authType) {
                    }

                    public void checkServerTrusted(X509Certificate[] certs, String authType) {
                    }

                }
        };
        SSLContext sslContext = SSLContext.getInstance("SSL");
        sslContext.init(null, trustAllCerts, new java.security.SecureRandom());
        httpsConnection.setSSLSocketFactory(new MyCustomSSLSocketFactory(sslContext.getSocketFactory()));

        httpsConnection.setHostnameVerifier((hostname, session) -> true);

        super.prepareConnection(httpsConnection, httpMethod);
    } catch (Exception e) {
        throw Throwables.propagate(e);
    }
}

/**
 * We need to invoke sslSocket.setEnabledProtocols(new String[] {"SSLv3"});
 * see http://www.oracle.com/technetwork/java/javase/documentation/cve-2014-3566-2342133.html (Java 8 section)
 */
private static class MyCustomSSLSocketFactory extends SSLSocketFactory {

    private final SSLSocketFactory delegate;

    public MyCustomSSLSocketFactory(SSLSocketFactory delegate) {
        this.delegate = delegate;
    }

    @Override
    public String[] getDefaultCipherSuites() {
        return delegate.getDefaultCipherSuites();
    }

    @Override
    public String[] getSupportedCipherSuites() {
        return delegate.getSupportedCipherSuites();
    }

    @Override
    public Socket createSocket(final Socket socket, final String host, final int port, final boolean autoClose) throws IOException {
        final Socket underlyingSocket = delegate.createSocket(socket, host, port, autoClose);
        return overrideProtocol(underlyingSocket);
    }

    @Override
    public Socket createSocket(final String host, final int port) throws IOException {
        final Socket underlyingSocket = delegate.createSocket(host, port);
        return overrideProtocol(underlyingSocket);
    }

    @Override
    public Socket createSocket(final String host, final int port, final InetAddress localAddress, final int localPort) throws IOException {
        final Socket underlyingSocket = delegate.createSocket(host, port, localAddress, localPort);
        return overrideProtocol(underlyingSocket);
    }

    @Override
    public Socket createSocket(final InetAddress host, final int port) throws IOException {
        final Socket underlyingSocket = delegate.createSocket(host, port);
        return overrideProtocol(underlyingSocket);
    }

    @Override
    public Socket createSocket(final InetAddress host, final int port, final InetAddress localAddress, final int localPort) throws IOException {
        final Socket underlyingSocket = delegate.createSocket(host, port, localAddress, localPort);
        return overrideProtocol(underlyingSocket);
    }

    private Socket overrideProtocol(final Socket socket) {
        if (!(socket instanceof SSLSocket)) {
            throw new RuntimeException("An instance of SSLSocket is expected");
        }
        ((SSLSocket) socket).setEnabledProtocols(new String[] {"SSLv3"});
        return socket;
    }
}
}

Write string to text file and ensure it always overwrites the existing content.

System.IO.File.WriteAllText (@"D:\path.txt", contents);
  • If the file exists, this overwrites it.
  • If the file does not exist, this creates it.
  • Please make sure you have appropriate privileges to write at the location, otherwise you will get an exception.

HTML select dropdown list

<select>
  <option value="" disabled selected hidden>Select an Option</option>
  <option value="one">Option 1</option>
  <option value="two">Option 2</option>
</select>

jQuery fade out then fade in

fade the other in in the callback of fadeout, which runs when fadeout is done. Using your code:

$('#two, #three').hide();
$('.slide').click(function(){
    var $this = $(this);
    $this.fadeOut(function(){ $this.next().fadeIn(); });
});

alternatively, you can just "pause" the chain, but you need to specify for how long:

$(this).fadeOut().next().delay(500).fadeIn();

How to check if all elements of a list matches a condition?

Another way to use itertools.ifilter. This checks truthiness and process (using lambda)

Sample-

for x in itertools.ifilter(lambda x: x[2] == 0, my_list):
    print x

Can I delete data from the iOS DeviceSupport directory?

More Suggestive answer supporting rmaddy's answer as our primary purpose is to delete unnecessary file and folder:

  1. Delete this folder after every few days interval. Most of the time, it occupy huge space!

      ~/Library/Developer/Xcode/DerivedData
    
  2. All your targets are kept in the archived form in Archives folder. Before you decide to delete contents of this folder, here is a warning - if you want to be able to debug deployed versions of your App, you shouldn’t delete the archives. Xcode will manage of archives and creates new file when new build is archived.

      ~/Library/Developer/Xcode/Archives
    
  3. iOS Device Support folder creates a subfolder with the device version as an identifier when you attach the device. Most of the time it’s just old stuff. Keep the latest version and rest of them can be deleted (if you don’t have an app that runs on 5.1.1, there’s no reason to keep the 5.1.1 directory/directories). If you really don't need these, delete. But we should keep a few although we test app from device mostly.

    ~/Library/Developer/Xcode/iOS DeviceSupport
    
  4. Core Simulator folder is familiar for many Xcode users. It’s simulator’s territory; that's where it stores app data. It’s obvious that you can toss the older version simulator folder/folders if you no longer support your apps for those versions. As it is user data, no big issue if you delete it completely but it’s safer to use ‘Reset Content and Settings’ option from the menu to delete all of your app data in a Simulator.

      ~/Library/Developer/CoreSimulator 
    

(Here's a handy shell command for step 5: xcrun simctl delete unavailable )

  1. Caches are always safe to delete since they will be recreated as necessary. This isn’t a directory; it’s a file of kind Xcode Project. Delete away!

    ~/Library/Caches/com.apple.dt.Xcode
    
  2. Additionally, Apple iOS device automatically syncs specific files and settings to your Mac every time they are connected to your Mac machine. To be on safe side, it’s wise to use Devices pane of iTunes preferences to delete older backups; you should be retaining your most recent back-ups off course.

     ~/Library/Application Support/MobileSync/Backup
    

Source: https://ajithrnayak.com/post/95441624221/xcode-users-can-free-up-space-on-your-mac

I got back about 40GB!

Why XML-Serializable class need a parameterless constructor

The answer is: for no good reason whatsoever.

Contrary to its name, the XmlSerializer class is used not only for serialization, but also for deserialization. It performs certain checks on your class to make sure that it will work, and some of those checks are only pertinent to deserialization, but it performs them all anyway, because it does not know what you intend to do later on.

The check that your class fails to pass is one of the checks that are only pertinent to deserialization. Here is what happens:

  • During deserialization, the XmlSerializer class will need to create instances of your type.

  • In order to create an instance of a type, a constructor of that type needs to be invoked.

  • If you did not declare a constructor, the compiler has already supplied a default parameterless constructor, but if you did declare a constructor, then that's the only constructor available.

  • So, if the constructor that you declared accepts parameters, then the only way to instantiate your class is by invoking that constructor which accepts parameters.

  • However, XmlSerializer is not capable of invoking any constructor except a parameterless constructor, because it does not know what parameters to pass to constructors that accept parameters. So, it checks to see if your class has a parameterless constructor, and since it does not, it fails.

So, if the XmlSerializer class had been written in such a way as to only perform the checks pertinent to serialization, then your class would pass, because there is absolutely nothing about serialization that makes it necessary to have a parameterless constructor.

As others have already pointed out, the quick solution to your problem is to simply add a parameterless constructor. Unfortunately, it is also a dirty solution, because it means that you cannot have any readonly members initialized from constructor parameters.

In addition to all this, the XmlSerializer class could have been written in such a way as to allow even deserialization of classes without parameterless constructors. All it would take would be to make use of "The Factory Method Design Pattern" (Wikipedia). From the looks of it, Microsoft decided that this design pattern is far too advanced for DotNet programmers, who apparently should not be unnecessarily confused with such things. So, DotNet programmers should better stick to parameterless constructors, according to Microsoft.

Executing a command stored in a variable from PowerShell

Try invoking your command with Invoke-Expression:

Invoke-Expression $cmd1

Here is a working example on my machine:

$cmd = "& 'C:\Program Files\7-zip\7z.exe' a -tzip c:\temp\test.zip c:\temp\test.txt"
Invoke-Expression $cmd

iex is an alias for Invoke-Expression so you could do:

iex $cmd1

For a full list : Visit https://ss64.com/ps/ for more Powershell stuff.

Good Luck...

Placeholder in IE9

If you want to input a description you can use this. This works on IE 9 and all other browsers.

<input type="text" onclick="if(this.value=='CVC2: '){this.value='';}" onblur="if(this.value==''){this.value='CVC2: ';}" value="CVC2: "/>

Laravel Migration Error: Syntax error or access violation: 1071 Specified key was too long; max key length is 767 bytes

I have solved this issue and edited my config->database.php file to like my database ('charset'=>'utf8') and the ('collation'=>'utf8_general_ci'), so my problem is solved the code as follow:

'mysql' => [
        'driver' => 'mysql',
        'host' => env('DB_HOST', '127.0.0.1'),
        'port' => env('DB_PORT', '3306'),
        'database' => env('DB_DATABASE', 'forge'),
        'username' => env('DB_USERNAME', 'forge'),
        'password' => env('DB_PASSWORD', ''),
        'unix_socket' => env('DB_SOCKET', ''),
        'charset' => 'utf8',
        'collation' => 'utf8_general_ci',
        'prefix' => '',
        'strict' => true,
        'engine' => null,
    ],

Renaming the current file in Vim

:sav newfile | !rm #

Note that it does not remove the old file from the buffer list. If that's important to you, you can use the following instead:

:sav newfile | bd# | !rm #

How to style a clicked button in CSS

Unfortunately, there is no :click pseudo selector. If you want to change styling on click, you should use Jquery/Javascript. It certainly is better than the "hack" for pure HTML / CSS. But if you insist...

_x000D_
_x000D_
input {_x000D_
display: none;_x000D_
}_x000D_
span {_x000D_
padding: 20px;_x000D_
font-family: sans-serif;_x000D_
}_x000D_
input:checked + span {_x000D_
  background: #444;_x000D_
  color: #fff;_x000D_
}
_x000D_
  <label for="input">_x000D_
  <input id="input" type="radio" />_x000D_
  <span>NO JS styling</span>_x000D_
  </label>
_x000D_
_x000D_
_x000D_

Or, if you prefer, you can toggle the styling:

_x000D_
_x000D_
input {_x000D_
display: none;_x000D_
}_x000D_
span {_x000D_
padding: 20px;_x000D_
font-family: sans-serif;_x000D_
}_x000D_
input:checked + span {_x000D_
  background: #444;_x000D_
  color: #fff;_x000D_
}
_x000D_
  <label for="input">_x000D_
  <input id="input" type="checkbox" />_x000D_
  <span>NO JS styling</span>_x000D_
  </label>
_x000D_
_x000D_
_x000D_

How to send Basic Auth with axios

For some reasons, this simple problem is blocking many developers. I struggled for many hours with this simple thing. This problem as many dimensions:

  1. CORS (if you are using a frontend and backend on different domains et ports.
  2. Backend CORS Configuration
  3. Basic Authentication configuration of Axios

CORS

My setup for development is with a vuejs webpack application running on localhost:8081 and a spring boot application running on localhost:8080. So when trying to call rest API from the frontend, there's no way that the browser will let me receive a response from the spring backend without proper CORS settings. CORS can be used to relax the Cross Domain Script (XSS) protection that modern browsers have. As I understand this, browsers are protecting your SPA from being an attack by an XSS. Of course, some answers on StackOverflow suggested to add a chrome plugin to disable XSS protection but this really does work AND if it was, would only push the inevitable problem for later.

Backend CORS configuration

Here's how you should setup CORS in your spring boot app:

Add a CorsFilter class to add proper headers in the response to a client request. Access-Control-Allow-Origin and Access-Control-Allow-Headers are the most important thing to have for basic authentication.

    public class CorsFilter implements Filter {

...
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        HttpServletRequest request = (HttpServletRequest) servletRequest;

        response.setHeader("Access-Control-Allow-Origin", "http://localhost:8081");
        response.setHeader("Access-Control-Allow-Methods", "GET, HEAD, POST, PUT, DELETE, TRACE, OPTIONS, PATCH");
        **response.setHeader("Access-Control-Allow-Headers", "authorization, Content-Type");**
        response.setHeader("Access-Control-Max-Age", "3600");

        filterChain.doFilter(servletRequest, servletResponse);

    }
...
}

Add a configuration class which extends Spring WebSecurityConfigurationAdapter. In this class you will inject your CORS filter:

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {
...
    @Bean
    CorsFilter corsFilter() {
        CorsFilter filter = new CorsFilter();
        return filter;
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {

        http.addFilterBefore(corsFilter(), SessionManagementFilter.class) //adds your custom CorsFilter
          .csrf()
          .disable()
          .authorizeRequests()
          .antMatchers("/api/login")
          .permitAll()
          .anyRequest()
          .authenticated()
          .and()
          .httpBasic()
          .authenticationEntryPoint(authenticationEntryPoint)
          .and()
          .authenticationProvider(getProvider());
    }
...
}

You don't have to put anything related to CORS in your controller.

Frontend

Now, in the frontend you need to create your axios query with the Authorization header:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="https://unpkg.com/vue"></script>
    <script src="https://unpkg.com/axios/dist/axios.min.js"></script>
</head>
<body>
<div id="app">
    <p>{{ status }}</p>
</div>
<script>
    var vm = new Vue({
        el: "#app",
        data: {
            status: ''
        },
        created: function () {
            this.getBackendResource();
        },
        methods: {
            getBackendResource: function () {
                this.status = 'Loading...';
                var vm = this;
                var user = "aUserName";
                var pass = "aPassword";
                var url = 'http://localhost:8080/api/resource';

                var authorizationBasic = window.btoa(user + ':' + pass);
                var config = {
                    "headers": {
                        "Authorization": "Basic " + authorizationBasic
                    }
                };
                axios.get(url, config)
                    .then(function (response) {
                        vm.status = response.data[0];
                    })
                    .catch(function (error) {
                        vm.status = 'An error occured.' + error;
                    })
            }
        }
    })
</script>
</body>
</html>

Hope this helps.

Token based authentication in Web API without any user interface

ASP.Net Web API has Authorization Server build-in already. You can see it inside Startup.cs when you create a new ASP.Net Web Application with Web API template.

OAuthOptions = new OAuthAuthorizationServerOptions
{
    TokenEndpointPath = new PathString("/Token"),
    Provider = new ApplicationOAuthProvider(PublicClientId),
    AuthorizeEndpointPath = new PathString("/api/Account/ExternalLogin"),
    AccessTokenExpireTimeSpan = TimeSpan.FromDays(14),
    // In production mode set AllowInsecureHttp = false
    AllowInsecureHttp = true
};

All you have to do is to post URL encoded username and password inside query string.

/Token/userName=johndoe%40example.com&password=1234&grant_type=password

If you want to know more detail, you can watch User Registration and Login - Angular Front to Back with Web API by Deborah Kurata.

how to clear JTable

You must remove the data from the TableModel used for the table.

If using the DefaultTableModel, just set the row count to zero. This will delete the rows and fire the TableModelEvent to update the GUI.

JTable table;
…
DefaultTableModel model = (DefaultTableModel) table.getModel();
model.setRowCount(0);

If you are using other TableModel, please check the documentation.

Install windows service without InstallUtil.exe

Topshelf is an OSS project which was started after this question was answered and it makes Windows service much, MUCH easier.I highly recommend looking into it.

http://topshelf-project.com/

Using curl POST with variables defined in bash script functions

Here's what actually worked for me, after guidance from answers here:

export BASH_VARIABLE="[1,2,3]"
curl http://localhost:8080/path -d "$(cat <<EOF
{
  "name": $BASH_VARIABLE,
  "something": [
    "value1",
    "value2",
    "value3"
  ]
}
EOF
)" -H 'Content-Type: application/json'

Python lookup hostname from IP with 1 second timeout

>>> import socket
>>> socket.gethostbyaddr("69.59.196.211")
('stackoverflow.com', ['211.196.59.69.in-addr.arpa'], ['69.59.196.211'])

For implementing the timeout on the function, this stackoverflow thread has answers on that.

CSS filter: make color image with transparency white

You can use

filter: brightness(0) invert(1);

_x000D_
_x000D_
html {_x000D_
  background: red;_x000D_
}_x000D_
p {_x000D_
  float: left;_x000D_
  max-width: 50%;_x000D_
  text-align: center;_x000D_
}_x000D_
img {_x000D_
  display: block;_x000D_
  max-width: 100%;_x000D_
}_x000D_
.filter {_x000D_
  -webkit-filter: brightness(0) invert(1);_x000D_
  filter: brightness(0) invert(1);_x000D_
}
_x000D_
<p>_x000D_
  Original:_x000D_
  <img src="http://i.stack.imgur.com/jO8jP.gif" />_x000D_
</p>_x000D_
<p>_x000D_
  Filter:_x000D_
  <img src="http://i.stack.imgur.com/jO8jP.gif" class="filter" />_x000D_
</p>
_x000D_
_x000D_
_x000D_

First, brightness(0) makes all image black, except transparent parts, which remain transparent.

Then, invert(1) makes the black parts white.

How to read a text file into a list or an array with Python

So you want to create a list of lists... We need to start with an empty list

list_of_lists = []

next, we read the file content, line by line

with open('data') as f:
    for line in f:
        inner_list = [elt.strip() for elt in line.split(',')]
        # in alternative, if you need to use the file content as numbers
        # inner_list = [int(elt.strip()) for elt in line.split(',')]
        list_of_lists.append(inner_list)

A common use case is that of columnar data, but our units of storage are the rows of the file, that we have read one by one, so you may want to transpose your list of lists. This can be done with the following idiom

by_cols = zip(*list_of_lists)

Another common use is to give a name to each column

col_names = ('apples sold', 'pears sold', 'apples revenue', 'pears revenue')
by_names = {}
for i, col_name in enumerate(col_names):
    by_names[col_name] = by_cols[i]

so that you can operate on homogeneous data items

 mean_apple_prices = [money/fruits for money, fruits in
                     zip(by_names['apples revenue'], by_names['apples_sold'])]

Most of what I've written can be speeded up using the csv module, from the standard library. Another third party module is pandas, that lets you automate most aspects of a typical data analysis (but has a number of dependencies).


Update While in Python 2 zip(*list_of_lists) returns a different (transposed) list of lists, in Python 3 the situation has changed and zip(*list_of_lists) returns a zip object that is not subscriptable.

If you need indexed access you can use

by_cols = list(zip(*list_of_lists))

that gives you a list of lists in both versions of Python.

On the other hand, if you don't need indexed access and what you want is just to build a dictionary indexed by column names, a zip object is just fine...

file = open('some_data.csv')
names = get_names(next(file))
columns = zip(*((x.strip() for x in line.split(',')) for line in file)))
d = {}
for name, column in zip(names, columns): d[name] = column

JavaScript calculate the day of the year (1 - 366)

This is a simple way to find the current day in the year, and it should account for leap years without a problem:

Javascript:

Math.round((new Date().setHours(23) - new Date(new Date().getYear()+1900, 0, 1, 0, 0, 0))/1000/60/60/24);

Javascript in Google Apps Script:

Math.round((new Date().setHours(23) - new Date(new Date().getYear(), 0, 1, 0, 0, 0))/1000/60/60/24);

The primary action of this code is to find the number of milliseconds that have elapsed in the current year and then convert this number into days. The number of milliseconds that have elapsed in the current year can be found by subtracting the number of milliseconds of the first second of the first day of the current year, which is obtained with new Date(new Date().getYear()+1900, 0, 1, 0, 0, 0) (Javascript) or new Date(new Date().getYear(), 0, 1, 0, 0, 0) (Google Apps Script), from the milliseconds of the 23rd hour of the current day, which was found with new Date().setHours(23). The purpose of setting the current date to the 23rd hour is to ensure that the day of year is rounded correctly by Math.round().

Once you have the number of milliseconds of the current year, then you can convert this time into days by dividing by 1000 to convert milliseconds to seconds, then dividing by 60 to convert seconds to minutes, then dividing by 60 to convert minutes to hours, and finally dividing by 24 to convert hours to days.

Note: This post was edited to account for differences between JavaScript and JavaScript implemented in Google Apps Script. Also, more context was added for the answer.

Understanding ASP.NET Eval() and Bind()

For read-only controls they are the same. For 2 way databinding, using a datasource in which you want to update, insert, etc with declarative databinding, you'll need to use Bind.

Imagine for example a GridView with a ItemTemplate and EditItemTemplate. If you use Bind or Eval in the ItemTemplate, there will be no difference. If you use Eval in the EditItemTemplate, the value will not be able to be passed to the Update method of the DataSource that the grid is bound to.


UPDATE: I've come up with this example:

<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>Data binding demo</title>
</head>
<body>
    <form id="form1" runat="server">
        <asp:GridView 
            ID="grdTest" 
            runat="server" 
            AutoGenerateEditButton="true" 
            AutoGenerateColumns="false" 
            DataSourceID="mySource">
            <Columns>
                <asp:TemplateField>
                    <ItemTemplate>
                        <%# Eval("Name") %>
                    </ItemTemplate>
                    <EditItemTemplate>
                        <asp:TextBox 
                            ID="edtName" 
                            runat="server" 
                            Text='<%# Bind("Name") %>' 
                        />
                    </EditItemTemplate>
                </asp:TemplateField>
            </Columns>
        </asp:GridView>
    </form>

    <asp:ObjectDataSource 
        ID="mySource" 
        runat="server"
        SelectMethod="Select" 
        UpdateMethod="Update" 
        TypeName="MyCompany.CustomDataSource" />
</body>
</html>

And here's the definition of a custom class that serves as object data source:

public class CustomDataSource
{
    public class Model
    {
        public string Name { get; set; }
    }

    public IEnumerable<Model> Select()
    {
        return new[] 
        {
            new Model { Name = "some value" }
        };
    }

    public void Update(string Name)
    {
        // This method will be called if you used Bind for the TextBox
        // and you will be able to get the new name and update the
        // data source accordingly
    }

    public void Update()
    {
        // This method will be called if you used Eval for the TextBox
        // and you will not be able to get the new name that the user
        // entered
    }
}

Find TODO tags in Eclipse

Is there an easy way to view all methods which contain this comment? Some sort of menu option?

Yes, choose one of the following:

  1. Go to Window ? Show View ? Tasks (Not TaskList). The new view will show up where the "Console" and "Problems" tabs are by default.

  2. As mentioned elsewhere, you can see them next to the scroll bar as little blue rectangles if you have the source file in question open.

  3. If you just want the // TODO Auto-generated method stub messages (rather than all // TODO messages) you should use the search function (Ctrl-F for ones in this file Search ? Java Search ? Search string for the ability to specify this workspace, that file, this project, etc.)

pros and cons between os.path.exists vs os.path.isdir

os.path.exists(path) Returns True if path refers to an existing path. An existing path can be regular files (http://en.wikipedia.org/wiki/Unix_file_types#Regular_file), but also special files (e.g. a directory). So in essence this function returns true if the path provided exists in the filesystem in whatever form (notwithstanding a few exceptions such as broken symlinks).

os.path.isdir(path) in turn will only return true when the path points to a directory

How do I find an element position in std::vector?

Get rid of the notion of vector entirely

template< typename IT, typename VT>
int index_of(IT begin, IT end, const VT& val)
{
    int index = 0;
    for (; begin != end; ++begin)
    {
        if (*begin == val) return index;
    }
    return -1;
}

This will allow you more flexibility and let you use constructs like

int squid[] = {5,2,7,4,1,6,3,0};
int sponge[] = {4,2,4,2,4,6,2,6};
int squidlen = sizeof(squid)/sizeof(squid[0]);
int position = index_of(&squid[0], &squid[squidlen], 3);
if (position >= 0) { std::cout << sponge[position] << std::endl; }

You could also search any other container sequentially as well.

Understanding dispatch_async

All of the DISPATCH_QUEUE_PRIORITY_X queues are concurrent queues (meaning they can execute multiple tasks at once), and are FIFO in the sense that tasks within a given queue will begin executing using "first in, first out" order. This is in comparison to the main queue (from dispatch_get_main_queue()), which is a serial queue (tasks will begin executing and finish executing in the order in which they are received).

So, if you send 1000 dispatch_async() blocks to DISPATCH_QUEUE_PRIORITY_DEFAULT, those tasks will start executing in the order you sent them into the queue. Likewise for the HIGH, LOW, and BACKGROUND queues. Anything you send into any of these queues is executed in the background on alternate threads, away from your main application thread. Therefore, these queues are suitable for executing tasks such as background downloading, compression, computation, etc.

Note that the order of execution is FIFO on a per-queue basis. So if you send 1000 dispatch_async() tasks to the four different concurrent queues, evenly splitting them and sending them to BACKGROUND, LOW, DEFAULT and HIGH in order (ie you schedule the last 250 tasks on the HIGH queue), it's very likely that the first tasks you see starting will be on that HIGH queue as the system has taken your implication that those tasks need to get to the CPU as quickly as possible.

Note also that I say "will begin executing in order", but keep in mind that as concurrent queues things won't necessarily FINISH executing in order depending on length of time for each task.

As per Apple:

https://developer.apple.com/library/content/documentation/General/Conceptual/ConcurrencyProgrammingGuide/OperationQueues/OperationQueues.html

A concurrent dispatch queue is useful when you have multiple tasks that can run in parallel. A concurrent queue is still a queue in that it dequeues tasks in a first-in, first-out order; however, a concurrent queue may dequeue additional tasks before any previous tasks finish. The actual number of tasks executed by a concurrent queue at any given moment is variable and can change dynamically as conditions in your application change. Many factors affect the number of tasks executed by the concurrent queues, including the number of available cores, the amount of work being done by other processes, and the number and priority of tasks in other serial dispatch queues.

Basically, if you send those 1000 dispatch_async() blocks to a DEFAULT, HIGH, LOW, or BACKGROUND queue they will all start executing in the order you send them. However, shorter tasks may finish before longer ones. Reasons behind this are if there are available CPU cores or if the current queue tasks are performing computationally non-intensive work (thus making the system think it can dispatch additional tasks in parallel regardless of core count).

The level of concurrency is handled entirely by the system and is based on system load and other internally determined factors. This is the beauty of Grand Central Dispatch (the dispatch_async() system) - you just make your work units as code blocks, set a priority for them (based on the queue you choose) and let the system handle the rest.

So to answer your above question: you are partially correct. You are "asking that code" to perform concurrent tasks on a global concurrent queue at the specified priority level. The code in the block will execute in the background and any additional (similar) code will execute potentially in parallel depending on the system's assessment of available resources.

The "main" queue on the other hand (from dispatch_get_main_queue()) is a serial queue (not concurrent). Tasks sent to the main queue will always execute in order and will always finish in order. These tasks will also be executed on the UI Thread so it's suitable for updating your UI with progress messages, completion notifications, etc.

HttpServletRequest - Get query string parameters, no form data

The servlet API lacks this feature because it was created in a time when many believed that the query string and the message body was just two different ways of sending parameters, not realizing that the purposes of the parameters are fundamentally different.

The query string parameters ?foo=bar are a part of the URL because they are involved in identifying a resource (which could be a collection of many resources), like "all persons aged 42":

GET /persons?age=42

The message body parameters in POST or PUT are there to express a modification to the target resource(s). Fx setting a value to the attribute "hair":

PUT /persons?age=42

hair=grey

So it is definitely RESTful to use both query parameters and body parameters at the same time, separated so that you can use them for different purposes. The feature is definitely missing in the Java servlet API.

How can I remove an element from a list, with lodash?

lodash and typescript

const clearSubTopics = _.filter(obj.subTopics, topic => (!_.isEqual(topic.subTopicId, 2)));
console.log(clearSubTopics);

How to format a string as a telephone number in C#

This should work:

String.Format("{0:(###)###-####}", Convert.ToInt64("1112224444"));

OR in your case:

String.Format("{0:###-###-####}", Convert.ToInt64("1112224444"));

Equivalent to 'app.config' for a library (DLL)

Configuration files are application-scoped and not assembly-scoped. So you'll need to put your library's configuration sections in every application's configuration file that is using your library.

That said, it is not a good practice to get configuration from the application's configuration file, specially the appSettings section, in a class library. If your library needs parameters, they should probably be passed as method arguments in constructors, factory methods, etc. by whoever is calling your library. This prevents calling applications from accidentally reusing configuration entries that were expected by the class library.

That said, XML configuration files are extremely handy, so the best compromise that I've found is using custom configuration sections. You get to put your library's configuration in an XML file that is automatically read and parsed by the framework and you avoid potential accidents.

You can learn more about custom configuration sections on MSDN and also Phil Haack has a nice article on them.

force client disconnect from server with socket.io and nodejs

Socket.io uses the EventEmitter pattern to disconnect/connect/check heartbeats so you could do. Client.emit('disconnect');

Saving the PuTTY session logging

It works fine for me, but it's a little tricky :)

  • First open the PuTTY configuration.
  • Select the session (right part of the window, Saved Sessions)
  • Click Load (now you have loaded Host Name, Port and Connection type)
  • Then click Logging (under Session on the left)
  • Change whatever settings you want
  • Go back to Session window and click the Save button

Now you have settings for this session set (every time you load session it will be logged).

Cannot run Eclipse; JVM terminated. Exit code=13

Just uninstalled jre-32 bit version and It worked fine for me.

Error: "setFile(null,false) call failed" when using log4j

if it is window7(like mine), without administrative rights cannot write a file at C: drive

just give another folder in log4j.properties file

Set the name of the file

log4j.appender.FILE.File=C:\server\log.out you can see with notepad++

Convert decimal to hexadecimal in UNIX shell script

# number conversion.

while `test $ans='y'`
do
    echo "Menu"
    echo "1.Decimal to Hexadecimal"
    echo "2.Decimal to Octal"
    echo "3.Hexadecimal to Binary"
    echo "4.Octal to Binary"
    echo "5.Hexadecimal to  Octal"
    echo "6.Octal to Hexadecimal"
    echo "7.Exit"

    read choice
    case $choice in

        1) echo "Enter the decimal no."
           read n
           hex=`echo "ibase=10;obase=16;$n"|bc`
           echo "The hexadecimal no. is $hex"
           ;;

        2) echo "Enter the decimal no."
           read n
           oct=`echo "ibase=10;obase=8;$n"|bc`
           echo "The octal no. is $oct"
           ;;

        3) echo "Enter the hexadecimal no."
           read n
           binary=`echo "ibase=16;obase=2;$n"|bc`
           echo "The binary no. is $binary"
           ;;

        4) echo "Enter the octal no."
           read n
           binary=`echo "ibase=8;obase=2;$n"|bc`
           echo "The binary no. is $binary"
           ;;

        5) echo "Enter the hexadecimal no."
           read n
           oct=`echo "ibase=16;obase=8;$n"|bc`
           echo "The octal no. is $oct"
           ;;

        6) echo "Enter the octal no."
           read n
           hex=`echo "ibase=8;obase=16;$n"|bc`
           echo "The hexadecimal no. is $hex"
           ;;

        7) exit 
        ;;
        *) echo "invalid no." 
        ;;

    esac
done

Autoreload of modules in IPython

As mentioned above, you need the autoreload extension. If you want it to automatically start every time you launch ipython, you need to add it to the ipython_config.py startup file:

It may be necessary to generate one first:

ipython profile create

Then include these lines in ~/.ipython/profile_default/ipython_config.py:

c.InteractiveShellApp.exec_lines = []
c.InteractiveShellApp.exec_lines.append('%load_ext autoreload')
c.InteractiveShellApp.exec_lines.append('%autoreload 2')

As well as an optional warning in case you need to take advantage of compiled Python code in .pyc files:

c.InteractiveShellApp.exec_lines.append('print "Warning: disable autoreload in ipython_config.py to improve performance." ')

edit: the above works with version 0.12.1 and 0.13

How to get a index value from foreach loop in jstl

This works for me:

<c:forEach var="i" begin="1970" end="2000">
    <option value="${2000-(i-1970)}">${2000-(i-1970)} 
     </option>
</c:forEach>

What does "<html xmlns="http://www.w3.org/1999/xhtml">" do?

It sounds like your site has CSS or JS that depends on running in quirks mode. Which is why you need garbage above your doctype to render "correctly". I suggest removing said garbage and then fixing your CSS+JS to actually work in standards mode; you'll save yourself a lot of pain in the long run.

Count of "Defined" Array Elements

Remove the values then check (remove null check here if you want)

const x = A.filter(item => item !== undefined || item !== null).length

With Lodash

const x = _.size(_.filter(A, item => !_.isNil(item)))

returning a Void object

If you just don't need anything as your type, you can use void. This can be used for implementing functions, or actions. You could then do something like this:

interface Action<T> {
    public T execute();
}

abstract class VoidAction implements Action<Void> {
    public Void execute() {
        executeInternal();
        return null;
    }

    abstract void executeInternal();
}

Or you could omit the abstract class, and do the return null in every action that doesn't require a return value yourself.

You could then use those actions like this:

Given a method

private static <T> T executeAction(Action<T> action) {
    return action.execute();
}

you can call it like

String result = executeAction(new Action<String>() {
    @Override
    public String execute() {
        //code here
        return "Return me!";
    }
});

or, for the void action (note that you're not assigning the result to anything)

executeAction(new VoidAction() {
    @Override
    public void executeInternal() {
        //code here
    }
});

Disabling browser print options (headers, footers, margins) from page?

The CSS standard enables some advanced formatting. There is a @page directive in CSS that enables some formatting that applies only to paged media (like paper). See http://www.w3.org/TR/1998/REC-CSS2-19980512/page.html.

Downside is that behavior in different browsers is not consistent. Safari still does not support setting printer page margin at all, but all the other major browsers now support it.

With the @page directive, you can specify printer margin of the page (which is not the same as normal CSS margin of an HTML element):

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
    <title>Print Test</title>
    <style type="text/css" media="print">
    @page 
    {
        size:  auto;   /* auto is the initial value */
        margin: 0mm;  /* this affects the margin in the printer settings */
    }

    html
    {
        background-color: #FFFFFF; 
        margin: 0px;  /* this affects the margin on the html before sending to printer */
    }

    body
    {
        border: solid 1px blue ;
        margin: 10mm 15mm 10mm 15mm; /* margin you want for the content */
    }
    </style>
</head>
<body>
  <div>Top line</div>
  <div>Line 2</div>
</body>
</html>

Note that we basically disables the page-specific margins here to achieve the effect of removing the header and footer, so the margin we set on the body will not be used in page breaks (as commented by Konrad) This means that it will only work properly if the printed content is only one page.

This does not work in Firefox 3.6, IE 7, Safari 5.1.7 or Google Chrome 4.1.

Setting the @page margin does have effect in IE 8, Opera 10, Google Chrome 21 and Firefox 19.
Although the page margins are set correctly for your content in these browsers, the behavior is not ideal in trying to solve the hiding of the header/footer.

This is how it behaves in different browsers:

  • In Internet Explorer, the margin is actually set to 0mm in the settings for this printing, and if you do Preview you will get 0mm as default, but the user can change it in the preview.
    You will see that the page content actually are positioned correctly, but the browser print header and footer is shown with non-transparent background, and so effectively hiding the page content at that position.

  • In Firefox newer versions, it is positioned correctly, but both the header/footer text and content text is displayed, so it looks like a bad mix of browser header text and your page content.

  • In Opera, the page content hides the header when using a non-transparent background in the standard css and the header/footer position conflicts with content. Quite good, but looks strange if margin is set to a small value that causes the header to be partially visible. Also the page margin is not set properly.

  • In Chrome newer versions, the browser header and footer is hidden if the @page margin is set so small that the header/footer position conflicts with content. In my opinion, this is exactly how this should behave.

So the conclusion is that Chrome has the best implementation of this in respect to hiding the header/footer.

How to get document height and width without using jquery

How to find out the document width and height very easily?

in HTML
<span id="hidden_placer" style="position:absolute;right:0;bottom:0;visibility:hidden;"></span>

in javascript

     var c=document.querySelector('#hidden_placer');

     var r=c.getBoundingClientRect();
     r.right=document width
     r.bottom=document height`

You may update this on every window resize event, if needed.

ApplicationContextException: Unable to start ServletWebServerApplicationContext due to missing ServletWebServerFactory bean

Apart from the possible solutions in other answers, it is also possible that somehow Maven dependency corruption has occurred on your machine. I was facing the same error on trying to run my (Web) Spring boot application, and it got resolved by running the following -

mvn dependency:purge-local-repository -DreResolve=true

followed by

mvn package

I came onto this solution looking into another issue where Eclipse wouldn't let me run the main application class from the IDE, due to a different error, similar to one on this SO thread -> The type org.springframework.context.ConfigurableApplicationContext cannot be resolved. It is indirectly referenced from required .class files

Using C++ filestreams (fstream), how can you determine the size of a file?

Like this:

long begin, end;
ifstream myfile ("example.txt");
begin = myfile.tellg();
myfile.seekg (0, ios::end);
end = myfile.tellg();
myfile.close();
cout << "size: " << (end-begin) << " bytes." << endl;

TensorFlow, "'module' object has no attribute 'placeholder'"

If you are using TensorFlow 2.0, then some code developed for tf 1.x may not code work. Either you can follow the link : https://www.tensorflow.org/guide/migrate

or you can install a previous version of tf by pip3 install tensorflow==version

How to navigate to to different directories in the terminal (mac)?

To check that the file you're trying to open actually exists, you can change directories in terminal using cd. To change to ~/Desktop/sass/css: cd ~/Desktop/sass/css. To see what files are in the directory: ls.

If you want information about either of those commands, use the man page: man cd or man ls, for example.

Google for "basic unix command line commands" or similar; that will give you numerous examples of moving around, viewing files, etc in the command line.

On Mac OS X, you can also use open to open a finder window: open . will open the current directory in finder. (open ~/Desktop/sass/css will open the ~/Desktop/sass/css).

File path for project files?

You would do something like this to get the path "Data\ich_will.mp3" inside your application environments folder.

string fileName = "ich_will.mp3";
string path = Path.Combine(Environment.CurrentDirectory, @"Data\", fileName);

In my case it would return the following:

C:\MyProjects\Music\MusicApp\bin\Debug\Data\ich_will.mp3

I use Path.Combine and Environment.CurrentDirectory in my example. These are very useful and allows you to build a path based on the current location of your application. Path.Combine combines two or more strings to create a location, and Environment.CurrentDirectory provides you with the working directory of your application.

The working directory is not necessarily the same path as where your executable is located, but in most cases it should be, unless specified otherwise.

Dialog with transparent background in Android

One issue I found with all the existing answers is that the margins aren't preserved. This is because they all override the android:windowBackground attribute, which is responsible for margins, with a solid color. However, I did some digging in the Android SDK and found the default window background drawable, and modified it a bit to allow transparent dialogs.

First, copy /platforms/android-22/data/res/drawable/dialog_background_material.xml to your project. Or, just copy these lines into a new file:

<inset xmlns:android="http://schemas.android.com/apk/res/android"
    android:inset="16dp">
    <shape android:shape="rectangle">
        <corners android:radius="2dp" />
        <solid android:color="?attr/colorBackground" />
    </shape>
</inset>

Notice that android:color is set to ?attr/colorBackground. This is the default solid grey/white you see. To allow the color defined in android:background in your custom style to be transparent and show the transparency, all we have to do is change ?attr/colorBackground to @android:color/transparent. Now it will look like this:

<inset xmlns:android="http://schemas.android.com/apk/res/android"
    android:inset="16dp">
    <shape android:shape="rectangle">
        <corners android:radius="2dp" />
        <solid android:color="@android:color/transparent" />
    </shape>
</inset>

After that, go to your theme and add this:

<style name="MyTransparentDialog" parent="@android:style/Theme.Material.Dialog">
    <item name="android:windowBackground">@drawable/newly_created_background_name</item>
    <item name="android:background">@color/some_transparent_color</item>
</style>

Make sure to replace newly_created_background_name with the actual name of the drawable file you just created, and replace some_transparent_color with the desired transparent background.

After that all we need to do is set the theme. Use this when creating the AlertDialog.Builder:

    AlertDialog.Builder builder = new AlertDialog.Builder(this, R.style.MyTransparentDialog);

Then just build, create, and show the dialog as usual!

Add a new item to recyclerview programmatically?

if you are adding multiple items to the list use this:

mAdapter.notifyItemRangeInserted(startPosition, itemcount);

This notify any registered observers that the currently reflected itemCount items starting at positionStart have been newly inserted. The item previously located at positionStart and beyond can now be found starting at position positinStart+itemCount

existing item in the dataset still considered up to date.

how to check the dtype of a column in python pandas

Asked question title is general, but authors use case stated in the body of the question is specific. So any other answers may be used.

But in order to fully answer the title question it should be clarified that it seems like all of the approaches may fail in some cases and require some rework. I reviewed all of them (and some additional) in decreasing of reliability order (in my opinion):

1. Comparing types directly via == (accepted answer).

Despite the fact that this is accepted answer and has most upvotes count, I think this method should not be used at all. Because in fact this approach is discouraged in python as mentioned several times here.
But if one still want to use it - should be aware of some pandas-specific dtypes like pd.CategoricalDType, pd.PeriodDtype, or pd.IntervalDtype. Here one have to use extra type( ) in order to recognize dtype correctly:

s = pd.Series([pd.Period('2002-03','D'), pd.Period('2012-02-01', 'D')])
s
s.dtype == pd.PeriodDtype   # Not working
type(s.dtype) == pd.PeriodDtype # working 

>>> 0    2002-03-01
>>> 1    2012-02-01
>>> dtype: period[D]
>>> False
>>> True

Another caveat here is that type should be pointed out precisely:

s = pd.Series([1,2])
s
s.dtype == np.int64 # Working
s.dtype == np.int32 # Not working

>>> 0    1
>>> 1    2
>>> dtype: int64
>>> True
>>> False

2. isinstance() approach.

This method has not been mentioned in answers so far.

So if direct comparing of types is not a good idea - lets try built-in python function for this purpose, namely - isinstance().
It fails just in the beginning, because assumes that we have some objects, but pd.Series or pd.DataFrame may be used as just empty containers with predefined dtype but no objects in it:

s = pd.Series([], dtype=bool)
s

>>> Series([], dtype: bool)

But if one somehow overcome this issue, and wants to access each object, for example, in the first row and checks its dtype like something like that:

df = pd.DataFrame({'int': [12, 2], 'dt': [pd.Timestamp('2013-01-02'), pd.Timestamp('2016-10-20')]},
                  index = ['A', 'B'])
for col in df.columns:
    df[col].dtype, 'is_int64 = %s' % isinstance(df.loc['A', col], np.int64)

>>> (dtype('int64'), 'is_int64 = True')
>>> (dtype('<M8[ns]'), 'is_int64 = False')

It will be misleading in the case of mixed type of data in single column:

df2 = pd.DataFrame({'data': [12, pd.Timestamp('2013-01-02')]},
                  index = ['A', 'B'])
for col in df2.columns:
    df2[col].dtype, 'is_int64 = %s' % isinstance(df2.loc['A', col], np.int64)

>>> (dtype('O'), 'is_int64 = False')

And last but not least - this method cannot directly recognize Category dtype. As stated in docs:

Returning a single item from categorical data will also return the value, not a categorical of length “1”.

df['int'] = df['int'].astype('category')
for col in df.columns:
    df[col].dtype, 'is_int64 = %s' % isinstance(df.loc['A', col], np.int64)

>>> (CategoricalDtype(categories=[2, 12], ordered=False), 'is_int64 = True')
>>> (dtype('<M8[ns]'), 'is_int64 = False')

So this method is also almost inapplicable.

3. df.dtype.kind approach.

This method yet may work with empty pd.Series or pd.DataFrames but has another problems.

First - it is unable to differ some dtypes:

df = pd.DataFrame({'prd'  :[pd.Period('2002-03','D'), pd.Period('2012-02-01', 'D')],
                   'str'  :['s1', 's2'],
                   'cat'  :[1, -1]})
df['cat'] = df['cat'].astype('category')
for col in df:
    # kind will define all columns as 'Object'
    print (df[col].dtype, df[col].dtype.kind)

>>> period[D] O
>>> object O
>>> category O

Second, what is actually still unclear for me, it even returns on some dtypes None.

4. df.select_dtypes approach.

This is almost what we want. This method designed inside pandas so it handles most corner cases mentioned earlier - empty DataFrames, differs numpy or pandas-specific dtypes well. It works well with single dtype like .select_dtypes('bool'). It may be used even for selecting groups of columns based on dtype:

test = pd.DataFrame({'bool' :[False, True], 'int64':[-1,2], 'int32':[-1,2],'float': [-2.5, 3.4],
                     'compl':np.array([1-1j, 5]),
                     'dt'   :[pd.Timestamp('2013-01-02'), pd.Timestamp('2016-10-20')],
                     'td'   :[pd.Timestamp('2012-03-02')- pd.Timestamp('2016-10-20'),
                              pd.Timestamp('2010-07-12')- pd.Timestamp('2000-11-10')],
                     'prd'  :[pd.Period('2002-03','D'), pd.Period('2012-02-01', 'D')],
                     'intrv':pd.arrays.IntervalArray([pd.Interval(0, 0.1), pd.Interval(1, 5)]),
                     'str'  :['s1', 's2'],
                     'cat'  :[1, -1],
                     'obj'  :[[1,2,3], [5435,35,-52,14]]
                    })
test['int32'] = test['int32'].astype(np.int32)
test['cat'] = test['cat'].astype('category')

Like so, as stated in the docs:

test.select_dtypes('number')

>>>     int64   int32   float   compl   td
>>> 0      -1      -1   -2.5    (1-1j)  -1693 days
>>> 1       2       2    3.4    (5+0j)   3531 days

On may think that here we see first unexpected (at used to be for me: question) results - TimeDelta is included into output DataFrame. But as answered in contrary it should be so, but one have to be aware of it. Note that bool dtype is skipped, that may be also undesired for someone, but it's due to bool and number are in different "subtrees" of numpy dtypes. In case with bool, we may use test.select_dtypes(['bool']) here.

Next restriction of this method is that for current version of pandas (0.24.2), this code: test.select_dtypes('period') will raise NotImplementedError.

And another thing is that it's unable to differ strings from other objects:

test.select_dtypes('object')

>>>     str     obj
>>> 0    s1     [1, 2, 3]
>>> 1    s2     [5435, 35, -52, 14]

But this is, first - already mentioned in the docs. And second - is not the problem of this method, rather the way strings are stored in DataFrame. But anyway this case have to have some post processing.

5. df.api.types.is_XXX_dtype approach.

This one is intended to be most robust and native way to achieve dtype recognition (path of the module where functions resides says by itself) as i suppose. And it works almost perfectly, but still have at least one caveat and still have to somehow distinguish string columns.

Besides, this may be subjective, but this approach also has more 'human-understandable' number dtypes group processing comparing with .select_dtypes('number'):

for col in test.columns:
    if pd.api.types.is_numeric_dtype(test[col]):
        print (test[col].dtype)

>>> bool
>>> int64
>>> int32
>>> float64
>>> complex128

No timedelta and bool is included. Perfect.

My pipeline exploits exactly this functionality at this moment of time, plus a bit of post hand processing.

Output.

Hope I was able to argument the main point - that all discussed approaches may be used, but only pd.DataFrame.select_dtypes() and pd.api.types.is_XXX_dtype should be really considered as the applicable ones.

ComboBox: Adding Text and Value to an Item (no Binding Source)

An example using DataTable:

DataTable dtblDataSource = new DataTable();
dtblDataSource.Columns.Add("DisplayMember");
dtblDataSource.Columns.Add("ValueMember");
dtblDataSource.Columns.Add("AdditionalInfo");

dtblDataSource.Rows.Add("Item 1", 1, "something useful 1");
dtblDataSource.Rows.Add("Item 2", 2, "something useful 2");
dtblDataSource.Rows.Add("Item 3", 3, "something useful 3");

combo1.Items.Clear();
combo1.DataSource = dtblDataSource;
combo1.DisplayMember = "DisplayMember";
combo1.ValueMember = "ValueMember";

   //Get additional info
   foreach (DataRowView drv in combo1.Items)
   {
         string strAdditionalInfo = drv["AdditionalInfo"].ToString();
   }

   //Get additional info for selected item
    string strAdditionalInfo = (combo1.SelectedItem as DataRowView)["AdditionalInfo"].ToString();

   //Get selected value
   string strSelectedValue = combo1.SelectedValue.ToString();

The client and server cannot communicate, because they do not possess a common algorithm - ASP.NET C# IIS TLS 1.0 / 1.1 / 1.2 - Win32Exception

My app is running in .net 4.7.2. Simplest solution was to add this to the config:

  <system.web>
    <httpRuntime targetFramework="4.7.2"/>
  </system.web>

Whoops, looks like something went wrong. Laravel 5.0

Go to project directory then follow below steps.

step 1: rename file .env.example `to .env

mv .env.example .env (for linux)

step 2: php artisan key:generate

What's the difference between abstraction and encapsulation?

My opinion of abstraction is not in the sense of hiding implementation or background details!

Abstraction gives us the benefit to deal with a representation of the real world which is easier to handle, has the ability to be reused, could be combined with other components of our more or less complex program package. So we have to find out how we pick a complete peace of the real world, which is complete enough to represent the sense of our algorithm and data. The implementation of the interface may hide the details but this is not part of the work we have to do for abstracting something.

For me most important thing for abstraction is:

  1. reduction of complexity
  2. reduction of size/quantity
  3. splitting of non related domains to clear and independent components

All this has for me nothing to do with hiding background details!

If you think of sorting some data, abstraction can result in:

  1. a sorting algorithm, which is independent of the data representation
  2. a compare function, which is independent of data and sort algorithm
  3. a generic data representation, which is independent of the used algorithms

All these has nothing to do with hiding information.

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

I think we can answer it much more succinctly. I answered a related question, and copying my answer from there

But first, an NP-hard problem is a problem for which we cannot prove that a polynomial time solution exists. NP-hardness of some "problem-P" is usually proven by converting an already proven NP-hard problem to the "problem-P" in polynomial time.

To answer the rest of question, you first need to understand which NP-hard problems are also NP-complete. If an NP-hard problem belongs to set NP, then it is NP-complete. To belong to set NP, a problem needs to be

(i) a decision problem,
(ii) the number of solutions to the problem should be finite and each solution should be of polynomial length, and
(iii) given a polynomial length solution, we should be able to say whether the answer to the problem is yes/no

Now, it is easy to see that there could be many NP-hard problems that do not belong to set NP and are harder to solve. As an intuitive example, the optimization-version of traveling salesman where we need to find an actual schedule is harder than the decision-version of traveling salesman where we just need to determine whether a schedule with length <= k exists or not.

Jquery Value match Regex

Change it to this:

var email = /^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$/i;

This is a regular expression literal that is passed the i flag which means to be case insensitive.

Keep in mind that email address validation is hard (there is a 4 or 5 page regular expression at the end of Mastering Regular Expressions demonstrating this) and your expression certainly will not capture all valid e-mail addresses.

How to get longitude and latitude of any address?

Use the following code for getting lat and long using php. Here are two methods:

Type-1:

    <?php
     // Get lat and long by address         
        $address = $dlocation; // Google HQ
        $prepAddr = str_replace(' ','+',$address);
        $geocode=file_get_contents('https://maps.google.com/maps/api/geocode/json?address='.$prepAddr.'&sensor=false');
        $output= json_decode($geocode);
        $latitude = $output->results[0]->geometry->location->lat;
        $longitude = $output->results[0]->geometry->location->lng;

?>

edit - Google Maps requests must be over https

Type-2:

<script src="https://maps.googleapis.com/maps/api/js?v=3.exp&sensor=false"></script>
     <script>
      var geocoder;
      var map;
      function initialize() {
        geocoder = new google.maps.Geocoder();
         var latlng = new google.maps.LatLng(50.804400, -1.147250);
        var mapOptions = {
         zoom: 6,
         center: latlng
        }
         map = new google.maps.Map(document.getElementById('map-canvas12'), mapOptions);
        }

       function codeAddress(address,tutorname,url,distance,prise,postcode) {
       var address = address;

        geocoder.geocode( { 'address': address}, function(results, status) {
         if (status == google.maps.GeocoderStatus.OK) {
          map.setCenter(results[0].geometry.location);
           var marker = new google.maps.Marker({
          map: map,
          position: results[0].geometry.location
      });

      var infowindow = new google.maps.InfoWindow({
         content: 'Tutor Name: '+tutorname+'<br>Price Guide: '+prise+'<br>Distance: '+distance+' Miles from you('+postcode+')<br> <a href="'+url+'" target="blank">View Tutor profile</a> '
       });
        infowindow.open(map,marker);

          } /*else {
          alert('Geocode was not successful for the following reason: ' + status);
        }*/
       });
     }


      google.maps.event.addDomListener(window, 'load', initialize);

     window.onload = function(){
      initialize();
      // your code here
      <?php foreach($addr as $add) { 

      ?>
      codeAddress('<?php echo $add['address']; ?>','<?php echo $add['tutorname']; ?>','<?php echo $add['url']; ?>','<?php echo $add['distance']; ?>','<?php echo $add['prise']; ?>','<?php echo substr( $postcode1,0,4); ?>');
      <?php } ?>
    };
      </script>

     <div id="map-canvas12"></div>

How can I check what version/edition of Visual Studio is installed programmatically?

All the information in this thread is now out of date with the recent release of vswhere. Download that and use it.

How to set the environmental variable LD_LIBRARY_PATH in linux

You could try adding a custom script, say myenv_vars.sh in /etc/profile.d.

cd /etc/profile.d
sudo touch myenv_vars.sh
sudo gedit myenv_vars.sh

Add this to the empty file, and save it.

export LD_LIBRARY_PATH=/usr/local/lib

Logout and login, LD_LIBRARY_PATH will have been set permanently.

HTML entity for check mark

There is HTML entity &#10003 but it doesn't work in some older browsers.

CSS file not refreshing in browser

This sounds like your browser is caching your css. If you are using Firefox, try loading your page using Shift-Reload.

Redis strings vs Redis hashes to represent JSON: efficiency?

Some additions to a given set of answers:

First of all if you going to use Redis hash efficiently you must know a keys count max number and values max size - otherwise if they break out hash-max-ziplist-value or hash-max-ziplist-entries Redis will convert it to practically usual key/value pairs under a hood. ( see hash-max-ziplist-value, hash-max-ziplist-entries ) And breaking under a hood from a hash options IS REALLY BAD, because each usual key/value pair inside Redis use +90 bytes per pair.

It means that if you start with option two and accidentally break out of max-hash-ziplist-value you will get +90 bytes per EACH ATTRIBUTE you have inside user model! ( actually not the +90 but +70 see console output below )

 # you need me-redis and awesome-print gems to run exact code
 redis = Redis.include(MeRedis).configure( hash_max_ziplist_value: 64, hash_max_ziplist_entries: 512 ).new 
  => #<Redis client v4.0.1 for redis://127.0.0.1:6379/0> 
 > redis.flushdb
  => "OK" 
 > ap redis.info(:memory)
    {
                "used_memory" => "529512",
          **"used_memory_human" => "517.10K"**,
            ....
    }
  => nil 
 # me_set( 't:i' ... ) same as hset( 't:i/512', i % 512 ... )    
 # txt is some english fictionary book around 56K length, 
 # so we just take some random 63-symbols string from it 
 > redis.pipelined{ 10000.times{ |i| redis.me_set( "t:#{i}", txt[rand(50000), 63] ) } }; :done
 => :done 
 > ap redis.info(:memory)
  {
               "used_memory" => "1251944",
         **"used_memory_human" => "1.19M"**, # ~ 72b per key/value
            .....
  }
  > redis.flushdb
  => "OK" 
  # setting **only one value** +1 byte per hash of 512 values equal to set them all +1 byte 
  > redis.pipelined{ 10000.times{ |i| redis.me_set( "t:#{i}", txt[rand(50000), i % 512 == 0 ? 65 : 63] ) } }; :done 
  > ap redis.info(:memory)
   {
               "used_memory" => "1876064",
         "used_memory_human" => "1.79M",   # ~ 134 bytes per pair  
          ....
   }
    redis.pipelined{ 10000.times{ |i| redis.set( "t:#{i}", txt[rand(50000), 65] ) } };
    ap redis.info(:memory)
    {
             "used_memory" => "2262312",
          "used_memory_human" => "2.16M", #~155 byte per pair i.e. +90 bytes    
           ....
    }

For TheHippo answer, comments on Option one are misleading:

hgetall/hmset/hmget to the rescue if you need all fields or multiple get/set operation.

For BMiner answer.

Third option is actually really fun, for dataset with max(id) < has-max-ziplist-value this solution has O(N) complexity, because, surprise, Reddis store small hashes as array-like container of length/key/value objects!

But many times hashes contain just a few fields. When hashes are small we can instead just encode them in an O(N) data structure, like a linear array with length-prefixed key value pairs. Since we do this only when N is small, the amortized time for HGET and HSET commands is still O(1): the hash will be converted into a real hash table as soon as the number of elements it contains will grow too much

But you should not worry, you'll break hash-max-ziplist-entries very fast and there you go you are now actually at solution number 1.

Second option will most likely go to the fourth solution under a hood because as question states:

Keep in mind that if I use a hash, the value length isn't predictable. They're not all short such as the bio example above.

And as you already said: the fourth solution is the most expensive +70 byte per each attribute for sure.

My suggestion how to optimize such dataset:

You've got two options:

  1. If you cannot guarantee max size of some user attributes than you go for first solution and if memory matter is crucial than compress user json before store in redis.

  2. If you can force max size of all attributes. Than you can set hash-max-ziplist-entries/value and use hashes either as one hash per user representation OR as hash memory optimization from this topic of a Redis guide: https://redis.io/topics/memory-optimization and store user as json string. Either way you may also compress long user attributes.

What does the arrow operator, '->', do in Java?

This one is useful as well when you want to implement a functional interface

Runnable r = ()-> System.out.print("Run method");

is equivalent to

Runnable r = new Runnable() {
        @Override
        public void run() {
            System.out.print("Run method");
        }
};

Remove from the beginning of std::vector

Given

std::vector<Rule>& topPriorityRules;

The correct way to remove the first element of the referenced vector is

topPriorityRules.erase(topPriorityRules.begin());

which is exactly what you suggested.

Looks like i need to do iterator overloading.

There is no need to overload an iterator in order to erase first element of std::vector.


P.S. Vector (dynamic array) is probably a wrong choice of data structure if you intend to erase from the front.

How do you do a limit query in JPQL or HQL?

Below snippet is used to perform limit query using HQL.

Query query = session.createQuery("....");
query.setFirstResult(startPosition);
query.setMaxResults(maxRows);

You can get demo application at this link.

Assign a synthesizable initial value to a reg in Verilog

You should use what your FPGA documentation recommends. There is no portable way to initialize register values other than using a reset net. This has a hardware cost associated with it on most synthesis targets.

How to check if a class inherits another class without instantiating it?

To check for assignability, you can use the Type.IsAssignableFrom method:

typeof(SomeType).IsAssignableFrom(typeof(Derived))

This will work as you expect for type-equality, inheritance-relationships and interface-implementations but not when you are looking for 'assignability' across explicit / implicit conversion operators.

To check for strict inheritance, you can use Type.IsSubclassOf:

typeof(Derived).IsSubclassOf(typeof(SomeType))

LINQ Joining in C# with multiple conditions

Your and should be a && in the where clause.

where epl.DepartAirportAfter >  sd.UTCDepartureTime 
and epl.ArriveAirportBy > sd.UTCArrivalTime

should be

where epl.DepartAirportAfter >  sd.UTCDepartureTime 
&& epl.ArriveAirportBy > sd.UTCArrivalTime

Is there a C# String.Format() equivalent in JavaScript?

Try sprintf() for javascript.

Or

// First, checks if it isn't implemented yet.
if (!String.prototype.format) {
  String.prototype.format = function() {
    var args = arguments;
    return this.replace(/{(\d+)}/g, function(match, number) { 
      return typeof args[number] != 'undefined'
        ? args[number]
        : match
      ;
    });
  };
}

"{0} is dead, but {1} is alive! {0} {2}".format("ASP", "ASP.NET")

Both answers pulled from JavaScript equivalent to printf/string.format

Oracle timestamp data type

Quite simply the number is the precision of the timestamp, the fraction of a second held in the column:

SQL> create table t23
  2  (ts0 timestamp(0)
  3   , ts3 timestamp(3)
  4  , ts6 timestamp(6)
  5  )
  6  /

Table created.

SQL> insert into t23 values (systimestamp, systimestamp, systimestamp)
  2  /

1 row created.

SQL> select * from t23
  2  /

TS0
---------------------------------------------------------------------------
TS3
---------------------------------------------------------------------------
TS6
---------------------------------------------------------------------------
24-JAN-12 05.57.12 AM
24-JAN-12 05.57.12.003 AM
24-JAN-12 05.57.12.002648 AM


SQL> 

If we don't specify a precision then the timestamp defaults to six places.

SQL> alter table t23 add ts_def timestamp;

Table altered.

SQL> update t23      
  2  set ts_def = systimestamp
  3  /

1 row updated.

SQL> select * from t23
  2  /

TS0
---------------------------------------------------------------------------
TS3
---------------------------------------------------------------------------
TS6
---------------------------------------------------------------------------
TS_DEF
---------------------------------------------------------------------------
24-JAN-12 05.57.12 AM
24-JAN-12 05.57.12.003 AM
24-JAN-12 05.57.12.002648 AM
24-JAN-12 05.59.27.293305 AM


SQL> 

Note that I'm running on Linux so my TIMESTAMP column actually gives me precision to six places i.e. microseconds. This would also be the case on most (all?) flavours of Unix. On Windows the limit is three places i.e. milliseconds. (Is this still true of the most modern flavours of Windows - citation needed).

As might be expected, the documentation covers this. Find out more.


"when you create timestamp(9) this gives you nanos right"

Only if the OS supports it. As you can see, my OEL appliance does not:

SQL> alter table t23 add ts_nano timestamp(9)
  2  /

Table altered.

SQL> update t23 set ts_nano = systimestamp(9)
  2  /

1 row updated.

SQL> select * from t23
  2  /

TS0
---------------------------------------------------------------------------
TS3
---------------------------------------------------------------------------
TS6
---------------------------------------------------------------------------
TS_DEF
---------------------------------------------------------------------------
TS_NANO
---------------------------------------------------------------------------
24-JAN-12 05.57.12 AM
24-JAN-12 05.57.12.003 AM
24-JAN-12 05.57.12.002648 AM
24-JAN-12 05.59.27.293305 AM
24-JAN-12 08.28.03.990557000 AM


SQL> 

(Those trailing zeroes could be a coincidence but they aren't.)

Beginner question: returning a boolean value from a function in Python

Have your tried using the 'return' keyword?

def rps():
    return True

Minimum and maximum value of z-index?

A user above says "well, you'll never really need to go above 10 for most designs."

Depending on your project, you may only need z-indexes 0-1, or z-indexes 0-10000. You'll often need to play in the higher digits...especially if you are working with lightbox viewers (9999 seems to be the standard and if you want to top their z-index, you'll need to exceed that!)

Count lines in large files

I have a 645GB text file, and none of the earlier exact solutions (e.g. wc -l) returned an answer within 5 minutes.

Instead, here is Python script that computes the approximate number of lines in a huge file. (My text file apparently has about 5.5 billion lines.) The Python script does the following:

A. Counts the number of bytes in the file.

B. Reads the first N lines in the file (as a sample) and computes the average line length.

C. Computes A/B as the approximate number of lines.

It follows along the line of Nico's answer, but instead of taking the length of one line, it computes the average length of the first N lines.

Note: I'm assuming an ASCII text file, so I expect the Python len() function to return the number of chars as the number of bytes.

Put this code into a file line_length.py:

#!/usr/bin/env python

# Usage:
# python line_length.py <filename> <N> 

import os
import sys
import numpy as np

if __name__ == '__main__':

    file_name = sys.argv[1]
    N = int(sys.argv[2]) # Number of first lines to use as sample.
    file_length_in_bytes = os.path.getsize(file_name)
    lengths = [] # Accumulate line lengths.
    num_lines = 0

    with open(file_name) as f:
        for line in f:
            num_lines += 1
            if num_lines > N:
                break
            lengths.append(len(line))

    arr = np.array(lengths)
    lines_count = len(arr)
    line_length_mean = np.mean(arr)
    line_length_std = np.std(arr)

    line_count_mean = file_length_in_bytes / line_length_mean

    print('File has %d bytes.' % (file_length_in_bytes))
    print('%.2f mean bytes per line (%.2f std)' % (line_length_mean, line_length_std))
    print('Approximately %d lines' % (line_count_mean))

Invoke it like this with N=5000.

% python line_length.py big_file.txt 5000

File has 645620992933 bytes.
116.34 mean bytes per line (42.11 std)
Approximately 5549547119 lines

So there are about 5.5 billion lines in the file.

Using Regular Expressions to Extract a Value in Java

Simple Solution

// Regexplanation:
// ^       beginning of line
// \\D+    1+ non-digit characters
// (\\d+)  1+ digit characters in a capture group
// .*      0+ any character
String regexStr = "^\\D+(\\d+).*";

// Compile the regex String into a Pattern
Pattern p = Pattern.compile(regexStr);

// Create a matcher with the input String
Matcher m = p.matcher(inputStr);

// If we find a match
if (m.find()) {
    // Get the String from the first capture group
    String someDigits = m.group(1);
    // ...do something with someDigits
}

Solution in a Util Class

public class MyUtil {
    private static Pattern pattern = Pattern.compile("^\\D+(\\d+).*");
    private static Matcher matcher = pattern.matcher("");

    // Assumptions: inputStr is a non-null String
    public static String extractFirstNumber(String inputStr){
        // Reset the matcher with a new input String
        matcher.reset(inputStr);

        // Check if there's a match
        if(matcher.find()){
            // Return the number (in the first capture group)
            return matcher.group(1);
        }else{
            // Return some default value, if there is no match
            return null;
        }
    }
}

...

// Use the util function and print out the result
String firstNum = MyUtil.extractFirstNumber("Testing4234Things");
System.out.println(firstNum);

C#: Looping through lines of multiline string

I suggest using a combination of StringReader and my LineReader class, which is part of MiscUtil but also available in this StackOverflow answer - you can easily copy just that class into your own utility project. You'd use it like this:

string text = @"First line
second line
third line";

foreach (string line in new LineReader(() => new StringReader(text)))
{
    Console.WriteLine(line);
}

Looping over all the lines in a body of string data (whether that's a file or whatever) is so common that it shouldn't require the calling code to be testing for null etc :) Having said that, if you do want to do a manual loop, this is the form that I typically prefer over Fredrik's:

using (StringReader reader = new StringReader(input))
{
    string line;
    while ((line = reader.ReadLine()) != null)
    {
        // Do something with the line
    }
}

This way you only have to test for nullity once, and you don't have to think about a do/while loop either (which for some reason always takes me more effort to read than a straight while loop).

How to change date format in JavaScript

Using the Datejs library, this can be as easy as:

Date.parse("05/05/2010").toString("MMMM yyyy");
//          parse date             convert to
//                                 string with
//                                 custom format

how can I enable scrollbars on the WPF Datagrid?

This worked for me. The key is to use * as Row height.

<Grid x:Name="grid">
        <Grid.RowDefinitions>
            <RowDefinition Height="60"/>
            <RowDefinition Height="*"/>
            <RowDefinition Height="10"/>
        </Grid.RowDefinitions>

        <TabControl  Grid.Row="1" x:Name="tabItem">
                <TabItem x:Name="ta" 
                        Header="List of all Clients">
                        <DataGrid Name="clientsgrid" AutoGenerateColumns="True" Margin="2" 
                         ></DataGrid>
                </TabItem>
        </TabControl>
    
    </Grid>

Why this line xmlns:android="http://schemas.android.com/apk/res/android" must be the first in the layout xml file?

xmlns refers to the XML namespace

When using prefixes in XML, a so-called namespace for the prefix must be defined. The namespace is defined by the xmlns attribute in the start tag of an element. The namespace declaration has the following syntax. xmlns:prefix="URI".

Note: The namespace URI is not used by the parser to look up information.

The purpose is to give the namespace a unique name. However, often companies use the namespace as a pointer to a web page containing namespace information.

Can you pass parameters to an AngularJS controller on creation?

Notes:

This answer is old. This is just a proof of concept on how the desired outcome can be achieved. However, it may not be the best solution as per some comments below. I don't have any documentation to support or reject the following approach. Please refer to some of the comments below for further discussion on this topic.

Original Answer:

I answered this to Yes you absolutely can do so using ng-init and a simple init function.

Here is the example of it on plunker

HTML

<!DOCTYPE html>
<html ng-app="angularjs-starter">
  <head lang="en">
    <script src="//ajax.googleapis.com/ajax/libs/angularjs/1.0.3/angular.min.js"></script>
    <script src="app.js"></script>
  </head>  
  <body ng-controller="MainCtrl" ng-init="init('James Bond','007')">
    <h1>I am  {{name}} {{id}}</h1>
  </body>
</html>

JavaScript

var app = angular.module('angularjs-starter', []);

app.controller('MainCtrl', function($scope) {

  $scope.init = function(name, id)
  {
    //This function is sort of private constructor for controller
    $scope.id = id;
    $scope.name = name; 
    //Based on passed argument you can make a call to resource
    //and initialize more objects
    //$resource.getMeBond(007)
  };


});

Kill all processes for a given user

On Debian LINUX, I use: ps -o pid= -u username | xargs sudo kill -9.

With -o pid= the ps header is supressed, and the output is only the pid list. As far as I know, Debian shell is POSIX compliant.

Send and Receive a file in socket programming in Linux with C/C++ (GCC/G++)

Minimal runnable POSIX read + write example

Usage:

  1. get two computers on a LAN.

    For example, this will work if both computers are connected to your home router in most cases, which is how I tested it.

  2. On the server computer:

    1. Find the server local IP with ifconfig, e.g. 192.168.0.10

    2. Run:

      ./server output.tmp 12345
      
  3. On the client computer:

    printf 'ab\ncd\n' > input.tmp
    ./client input.tmp 192.168.0.10 12345
    
  4. Outcome: a file output.tmp is created on the sever computer containing 'ab\ncd\n'!

server.c

/*
Receive a file over a socket.

Saves it to output.tmp by default.

Interface:

    ./executable [<output_file> [<port>]]

Defaults:

- output_file: output.tmp
- port: 12345
*/

#define _XOPEN_SOURCE 700

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

#include <arpa/inet.h>
#include <fcntl.h>
#include <netdb.h> /* getprotobyname */
#include <netinet/in.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <unistd.h>

int main(int argc, char **argv) {
    char *file_path = "output.tmp";
    char buffer[BUFSIZ];
    char protoname[] = "tcp";
    int client_sockfd;
    int enable = 1;
    int filefd;
    int i;
    int server_sockfd;
    socklen_t client_len;
    ssize_t read_return;
    struct protoent *protoent;
    struct sockaddr_in client_address, server_address;
    unsigned short server_port = 12345u;

    if (argc > 1) {
        file_path = argv[1];
        if (argc > 2) {
            server_port = strtol(argv[2], NULL, 10);
        }
    }

    /* Create a socket and listen to it.. */
    protoent = getprotobyname(protoname);
    if (protoent == NULL) {
        perror("getprotobyname");
        exit(EXIT_FAILURE);
    }
    server_sockfd = socket(
        AF_INET,
        SOCK_STREAM,
        protoent->p_proto
    );
    if (server_sockfd == -1) {
        perror("socket");
        exit(EXIT_FAILURE);
    }
    if (setsockopt(server_sockfd, SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(enable)) < 0) {
        perror("setsockopt(SO_REUSEADDR) failed");
        exit(EXIT_FAILURE);
    }
    server_address.sin_family = AF_INET;
    server_address.sin_addr.s_addr = htonl(INADDR_ANY);
    server_address.sin_port = htons(server_port);
    if (bind(
            server_sockfd,
            (struct sockaddr*)&server_address,
            sizeof(server_address)
        ) == -1
    ) {
        perror("bind");
        exit(EXIT_FAILURE);
    }
    if (listen(server_sockfd, 5) == -1) {
        perror("listen");
        exit(EXIT_FAILURE);
    }
    fprintf(stderr, "listening on port %d\n", server_port);

    while (1) {
        client_len = sizeof(client_address);
        puts("waiting for client");
        client_sockfd = accept(
            server_sockfd,
            (struct sockaddr*)&client_address,
            &client_len
        );
        filefd = open(file_path,
                O_WRONLY | O_CREAT | O_TRUNC,
                S_IRUSR | S_IWUSR);
        if (filefd == -1) {
            perror("open");
            exit(EXIT_FAILURE);
        }
        do {
            read_return = read(client_sockfd, buffer, BUFSIZ);
            if (read_return == -1) {
                perror("read");
                exit(EXIT_FAILURE);
            }
            if (write(filefd, buffer, read_return) == -1) {
                perror("write");
                exit(EXIT_FAILURE);
            }
        } while (read_return > 0);
        close(filefd);
        close(client_sockfd);
    }
    return EXIT_SUCCESS;
}

client.c

/*
Send a file over a socket.

Interface:

    ./executable [<input_path> [<sever_hostname> [<port>]]]

Defaults:

- input_path: input.tmp
- server_hostname: 127.0.0.1
- port: 12345
*/

#define _XOPEN_SOURCE 700

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

#include <arpa/inet.h>
#include <fcntl.h>
#include <netdb.h> /* getprotobyname */
#include <netinet/in.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <unistd.h>

int main(int argc, char **argv) {
    char protoname[] = "tcp";
    struct protoent *protoent;
    char *file_path = "input.tmp";
    char *server_hostname = "127.0.0.1";
    char *server_reply = NULL;
    char *user_input = NULL;
    char buffer[BUFSIZ];
    in_addr_t in_addr;
    in_addr_t server_addr;
    int filefd;
    int sockfd;
    ssize_t i;
    ssize_t read_return;
    struct hostent *hostent;
    struct sockaddr_in sockaddr_in;
    unsigned short server_port = 12345;

    if (argc > 1) {
        file_path = argv[1];
        if (argc > 2) {
            server_hostname = argv[2];
            if (argc > 3) {
                server_port = strtol(argv[3], NULL, 10);
            }
        }
    }

    filefd = open(file_path, O_RDONLY);
    if (filefd == -1) {
        perror("open");
        exit(EXIT_FAILURE);
    }

    /* Get socket. */
    protoent = getprotobyname(protoname);
    if (protoent == NULL) {
        perror("getprotobyname");
        exit(EXIT_FAILURE);
    }
    sockfd = socket(AF_INET, SOCK_STREAM, protoent->p_proto);
    if (sockfd == -1) {
        perror("socket");
        exit(EXIT_FAILURE);
    }
    /* Prepare sockaddr_in. */
    hostent = gethostbyname(server_hostname);
    if (hostent == NULL) {
        fprintf(stderr, "error: gethostbyname(\"%s\")\n", server_hostname);
        exit(EXIT_FAILURE);
    }
    in_addr = inet_addr(inet_ntoa(*(struct in_addr*)*(hostent->h_addr_list)));
    if (in_addr == (in_addr_t)-1) {
        fprintf(stderr, "error: inet_addr(\"%s\")\n", *(hostent->h_addr_list));
        exit(EXIT_FAILURE);
    }
    sockaddr_in.sin_addr.s_addr = in_addr;
    sockaddr_in.sin_family = AF_INET;
    sockaddr_in.sin_port = htons(server_port);
    /* Do the actual connection. */
    if (connect(sockfd, (struct sockaddr*)&sockaddr_in, sizeof(sockaddr_in)) == -1) {
        perror("connect");
        return EXIT_FAILURE;
    }

    while (1) {
        read_return = read(filefd, buffer, BUFSIZ);
        if (read_return == 0)
            break;
        if (read_return == -1) {
            perror("read");
            exit(EXIT_FAILURE);
        }
        /* TODO use write loop: https://stackoverflow.com/questions/24259640/writing-a-full-buffer-using-write-system-call */
        if (write(sockfd, buffer, read_return) == -1) {
            perror("write");
            exit(EXIT_FAILURE);
        }
    }
    free(user_input);
    free(server_reply);
    close(filefd);
    exit(EXIT_SUCCESS);
}

GitHub upstream.

Further comments

Possible improvements:

  • Currently output.tmp gets overwritten each time a send is done.

    This begs for the creation of a simple protocol that allows to pass a filename so that multiple files can be uploaded, e.g.: filename up to the first newline character, max filename 256 chars, and the rest until socket closure are the contents. Of course, that would require sanitation to avoid a path transversal vulnerability.

    Alternatively, we could make a server that hashes the files to find filenames, and keeps a map from original paths to hashes on disk (on a database).

  • Only one client can connect at a time.

    This is specially harmful if there are slow clients whose connections last for a long time: the slow connection halts everyone down.

    One way to work around that is to fork a process / thread for each accept, start listening again immediately, and use file lock synchronization on the files.

  • Add timeouts, and close clients if they take too long. Or else it would be easy to do a DoS.

    poll or select are some options: How to implement a timeout in read function call?

A simple HTTP wget implementation is shown at: How to make an HTTP get request in C without libcurl?

Tested on Ubuntu 15.10.

Compiling C++11 with g++

You can refer to following link for which features are supported in particular version of compiler. It has an exhaustive list of feature support in compiler. Looks GCC follows standard closely and implements before any other compiler.

Regarding your question you can compile using

  1. g++ -std=c++11 for C++11
  2. g++ -std=c++14 for C++14
  3. g++ -std=c++17 for C++17
  4. g++ -std=c++2a for C++20, although all features of C++20 are not yet supported refer this link for feature support list in GCC.

The list changes pretty fast, keep an eye on the list, if you are waiting for particular feature to be supported.