Programs & Examples On #Allegro

Allegro is a game programming library for C/C++ developers distributed freely, supporting the following platforms: Unix (Linux, FreeBSD, etc.), Windows, OS X, iOS, and Android.

fatal error LNK1169: one or more multiply defined symbols found in game programming

I answered a similar question here.

In the Project’s Settings, add /FORCE:MULTIPLE to the Linker’s Command Line options.

From MSDN: "Use /FORCE:MULTIPLE to create an output file whether or not LINK finds more than one definition for a symbol."

That's what programmers call a "quick and dirty" solution, but sometimes you just want the build to be completed and get to the bottom of the problem later, so that's kind of a ad-hoc solution. To actually avoid this error, provided that you want

int WIDTH = 1024;
int HEIGHT = 800;

to be shared among several source files, just declare them only in a single .c / .cpp file, and refer to them in a header file:

extern int WIDTH;
extern int HEIGHT;

Then include the header in any other source file you wish these global variables to be available.

Rotating a point about another point (2D)

This is the answer by Nils Pipenbrinck, but implemented in c# fiddle.

https://dotnetfiddle.net/btmjlG

using System;

public class Program
{
    public static void Main()
    {   
        var angle = 180 * Math.PI/180;
        Console.WriteLine(rotate_point(0,0,angle,new Point{X=10, Y=10}).Print());
    }

    static Point rotate_point(double cx, double cy, double angle, Point p)
    {
        double s = Math.Sin(angle);
        double c = Math.Cos(angle);
        // translate point back to origin:
        p.X -= cx;
        p.Y -= cy;
        // rotate point
        double Xnew = p.X * c - p.Y * s;
        double Ynew = p.X * s + p.Y * c;
        // translate point back:
        p.X = Xnew + cx;
        p.Y = Ynew + cy;
        return p;
    }

    class Point
    {
        public double X;
        public double Y;

        public string Print(){
            return $"{X},{Y}";
        }
    }
}

Ps: Apparently I can’t comment, so I’m obligated to post it as an answer ...

A full list of all the new/popular databases and their uses?

I doubt I'd use it in a mission-critical system, but Derby has always been very interesting to me.

Posting JSON data via jQuery to ASP .NET MVC 4 controller action

//simple json object in asp.net mvc

var model = {"Id": "xx", "Name":"Ravi"};
$.ajax({    url: 'test/[ControllerName]',
                        type: "POST",
                        data: model,
                        success: function (res) {
                            if (res != null) {
                                alert("done.");
                            }
                        },
                        error: function (res) {

                        }
                    });


//model in c#
public class MyModel
{
 public string Id {get; set;}
 public string Name {get; set;}
}

//controller in asp.net mvc


public ActionResult test(MyModel model)
{
 //now data in your model 
}

c++ array assignment of multiple values

You have to replace the values one by one such as in a for-loop or copying another array over another such as using memcpy(..) or std::copy

e.g.

for (int i = 0; i < arrayLength; i++) {
    array[i] = newValue[i];
}

Take care to ensure proper bounds-checking and any other checking that needs to occur to prevent an out of bounds problem.

oracle plsql: how to parse XML and insert into table

You can load an XML document into an XMLType, then query it, e.g.:

DECLARE
  x XMLType := XMLType(
    '<?xml version="1.0" ?> 
<person>
   <row>
       <name>Tom</name>
       <Address>
           <State>California</State>
           <City>Los angeles</City>
       </Address>
   </row>
   <row>
       <name>Jim</name>
       <Address>
           <State>California</State>
           <City>Los angeles</City>
       </Address>
   </row>
</person>');
BEGIN
  FOR r IN (
    SELECT ExtractValue(Value(p),'/row/name/text()') as name
          ,ExtractValue(Value(p),'/row/Address/State/text()') as state
          ,ExtractValue(Value(p),'/row/Address/City/text()') as city
    FROM   TABLE(XMLSequence(Extract(x,'/person/row'))) p
    ) LOOP
    -- do whatever you want with r.name, r.state, r.city
  END LOOP;
END;

Converting a generic list to a CSV string

in 3.5, i was still able to do this. Its much more simpler and doesnt need lambda.

String.Join(",", myList.ToArray<string>());

Vlookup referring to table data in a different sheet

Your formula looks fine. Maybe the value you are looking for is not in the first column of the second table?

If the second sheet is in another workbook, you need to add a Workbook reference to your formula:

=VLOOKUP(M3,[Book1]Sheet1!$A$2:$Q$47,13,FALSE)

How to add white spaces in HTML paragraph

If you really need then you can use i.e. &nbsp; entity to do that, but remember that fonts used to render your page are usually proportional, so "aligning" with spaces does not really work and looks ugly.

How do I encode and decode a base64 string?

You can display it like this:

var strOriginal = richTextBox1.Text;

byte[] byt = System.Text.Encoding.ASCII.GetBytes(strOriginal);

// convert the byte array to a Base64 string
string strModified = Convert.ToBase64String(byt);

richTextBox1.Text = "" + strModified;

Now, converting it back.

var base64EncodedBytes = System.Convert.FromBase64String(richTextBox1.Text);

richTextBox1.Text = "" + System.Text.Encoding.ASCII.GetString(base64EncodedBytes);
MessageBox.Show("Done Converting! (ASCII from base64)");

I hope this helps!

Multiple FROMs - what it means

As of May 2017, multiple FROMs can be used in a single Dockerfile.
See "Builder pattern vs. Multi-stage builds in Docker" (by Alex Ellis) and PR 31257 by Tõnis Tiigi.

The general syntax involves adding FROM additional times within your Dockerfile - whichever is the last FROM statement is the final base image. To copy artifacts and outputs from intermediate images use COPY --from=<base_image_number>.

FROM golang:1.7.3 as builder
WORKDIR /go/src/github.com/alexellis/href-counter/
RUN go get -d -v golang.org/x/net/html  
COPY app.go    .
RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o app .

FROM alpine:latest  
RUN apk --no-cache add ca-certificates
WORKDIR /root/
COPY --from=builder /go/src/github.com/alexellis/href-counter/app    .
CMD ["./app"]  

The result would be two images, one for building, one with just the resulting app (much, much smaller)

REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE

multi               latest              bcbbf69a9b59        6 minutes ago       10.3MB  
golang              1.7.3               ef15416724f6        4 months ago        672MB  

what is a base image?

A set of files, plus EXPOSE'd ports, ENTRYPOINT and CMD.
You can add files and build a new image based on that base image, with a new Dockerfile starting with a FROM directive: the image mentioned after FROM is "the base image" for your new image.

does it mean that if I declare neo4j/neo4j in a FROM directive, that when my image is run the neo database will automatically run and be available within the container on port 7474?

Only if you don't overwrite CMD and ENTRYPOINT.
But the image in itself is enough: you would use a FROM neo4j/neo4j if you had to add files related to neo4j for your particular usage of neo4j.

Simple PHP calculator

You also need to put the [== 'add'] math operation into quotes

if($_POST['group1'] == 'add') {
echo $first + $second;
}

complete code schould look like that :

<?php
$first = $_POST['first'];
$second= $_POST['second'];
if($_POST['group1'] == 'add') {
echo $first + $second;
}
else if($_POST['group1'] == 'subtract') {
echo $first - $second;
}
else if($_POST['group1'] == 'times') {
echo $first * $second;
} 
else if($_POST['group1'] == 'divide') {
echo $first / $second;
}
?>

getch and arrow codes

for a solution that uses ncurses with working code and initialization of ncurses see getchar() returns the same value (27) for up and down arrow keys

How to get a index value from foreach loop in jstl

<a onclick="getCategoryIndex(${myIndex.index})" href="#">${categoryName}</a>

above line was giving me an error. So I wrote down in below way which is working fine for me.

<a onclick="getCategoryIndex('<c:out value="${myIndex.index}"/>')" href="#">${categoryName}</a>

Maybe someone else might get same error. Look at this guys!

Escape single quote character for use in an SQLite query

Just in case if you have a loop or a json string that need to insert in the database. Try to replace the string with a single quote . here is my solution. example if you have a string that contain's a single quote.

String mystring = "Sample's";
String myfinalstring = mystring.replace("'","''");

 String query = "INSERT INTO "+table name+" ("+field1+") values ('"+myfinalstring+"')";

this works for me in c# and java

Adding a new line/break tag in XML

You are probably using Windows, so new line is CR + LF (carriage return + line feed). So solution would be:

<?xml version="1.0" encoding="utf-8"?>
<?xml-stylesheet type="text/xsl" href="dummy.xsl"?>
  <item>
     <summary>Tootsie roll tiramisu macaroon wafer carrot cake.&#13;&#10;Danish topping sugar plum tart bonbon caramels cake.
     </summary>
  </item>

For Linux there is only LF and for Mac OS only CR.

In question there showed Linux way.

How to communicate between iframe and the parent site?

Use event.source.window.postMessage to send back to sender.

From Iframe

window.top.postMessage('I am Iframe', '*')
window.onmessage = (event) => {
    if (event.data === 'GOT_YOU_IFRAME') {
        console.log('Parent received successfully.')
    }
}

Then from parent say back.

window.onmessage = (event) => {
    event.source.window.postMessage('GOT_YOU_IFRAME', '*')
}

Passing environment-dependent variables in webpack

To add to the bunch of answers personally I prefer the following:

const webpack = require('webpack');
const prod = process.argv.indexOf('-p') !== -1;

module.exports = {
  ...
  plugins: [
    new webpack.DefinePlugin({
      process: {
        env: {
          NODE_ENV: prod? `"production"`: '"development"'
        }
      }
    }),
    ...
  ]
};

Using this there is no funky env variable or cross-platform problems (with env vars). All you do is run the normal webpack or webpack -p for dev or production respectively.

Reference: Github issue

Pandas - 'Series' object has no attribute 'colNames' when using apply()

When you use df.apply(), each row of your DataFrame will be passed to your lambda function as a pandas Series. The frame's columns will then be the index of the series and you can access values using series[label].

So this should work:

df['D'] = (df.apply(lambda x: myfunc(x[colNames[0]], x[colNames[1]]), axis=1)) 

What are the parameters for the number Pipe - Angular 2

From the DOCS

Formats a number as text. Group sizing and separator and other locale-specific configurations are based on the active locale.

SYNTAX:

number_expression | number[:digitInfo[:locale]]

where expression is a number:

digitInfo is a string which has a following format:

{minIntegerDigits}.{minFractionDigits}-{maxFractionDigits}
  • minIntegerDigits is the minimum number of integer digits to use.Defaults to 1
  • minFractionDigits is the minimum number of digits
  • after fraction. Defaults to 0. maxFractionDigits is the maximum number of digits after fraction. Defaults to 3.
  • locale is a string defining the locale to use (uses the current LOCALE_ID by default)

DEMO

Using TortoiseSVN via the command line

As Joey pointed out, TortoiseSVN has a commandline syntax of its own. Unfortunately it is quite ugly, if you are used to svn commands, and it ignores the current working directory, thus it is not very usable - except for scripting.

I have created a little Python program (tsvn) which mimics the svn commandline syntax as closely as possible and calls TortoiseSVN accordingly. Thus, the difference between calling the normal commandline tools and calling TortoiseSVN is reduced to a little letter t at the beginning.

My tsvn program is not yet complete but already useful. It can be found in the cheeseshop (https://pypi.python.org/pypi/tsvn/)

Using Position Relative/Absolute within a TD?

This trick also suitable, but in this case align properties (middle, bottom etc.) won't be working.

<td style="display: block; position: relative;">
</td>

Exception.Message vs Exception.ToString()

In terms of the XML format for log4net, you need not worry about ex.ToString() for the logs. Simply pass the exception object itself and log4net does the rest do give you all of the details in its pre-configured XML format. The only thing I run into on occasion is new line formatting, but that's when I'm reading the files raw. Otherwise parsing the XML works great.

python exception message capturing

Using str(e) or repr(e) to represent the exception, you won't get the actual stack trace, so it is not helpful to find where the exception is.

After reading other answers and the logging package doc, the following two ways works great to print the actual stack trace for easier debugging:

use logger.debug() with parameter exc_info

try:
    # my code
except SomeError as e:
    logger.debug(e, exc_info=True)

use logger.exception()

or we can directly use logger.exception() to print the exception.

try:
    # my code
except SomeError as e:
    logger.exception(e)

"use database_name" command in PostgreSQL

Use this commad when first connect to psql

=# psql <databaseName> <usernamePostgresql>

How do you create a remote Git branch?

If you wanna actually just create remote branch without having the local one, you can do it like this:

git push origin HEAD:refs/heads/foo

It pushes whatever is your HEAD to branch foo that did not exist on the remote.

Go: panic: runtime error: invalid memory address or nil pointer dereference

for me one solution for this problem was to add in sql.Open ... sslmode=disable

Retrieve the commit log for a specific line in a file?

If the position of the line (line number) stays the same through the history of the file, this will show you the contents of the line at each commit:

git log --follow --pretty=format:"%h" -- 'path/to/file' | while read -r hash; do echo $hash && git show $hash:'path/to/file' | head -n 544 | tail -n1; done

Change 544 to the line number and path/to/file to the file path.

What's a good (free) visual merge tool for Git? (on windows)

On Windows, a good 3-way diff/merge tool remains kdiff3 (WinMerge, for now, is still 2-way based, pending WinMerge3)

See "How do you merge in GIT on Windows?" and this config.


Update 7 years later (Aug. 2018): Artur Kedzior mentions in the comments:

If you guys happen to use Visual Studio (Community Edition is free), try the tool that is shipped with it: vsDiffMerge.exe. It's really awesome and easy to use.

Javascript for "Add to Home Screen" on iPhone?

In 2020, this is still not possible on Mobile Safari.

The next best solution is to show instructions on the steps to adding your page to the homescreen.

enter image description here

Picture is from this great article which covers that an many other tips on how to make your PWA feel iOS native.

How to redirect output of an already running process

See Redirecting Output from a Running Process.

Firstly I run the command cat > foo1 in one session and test that data from stdin is copied to the file. Then in another session I redirect the output.

Firstly find the PID of the process:

$ ps aux | grep cat
rjc 6760 0.0 0.0 1580 376 pts/5 S+ 15:31 0:00 cat

Now check the file handles it has open:

$ ls -l /proc/6760/fd
total 3
lrwx—— 1 rjc rjc 64 Feb 27 15:32 0 -> /dev/pts/5
l-wx—— 1 rjc rjc 64 Feb 27 15:32 1 -> /tmp/foo1
lrwx—— 1 rjc rjc 64 Feb 27 15:32 2 -> /dev/pts/5

Now run GDB:

$ gdb -p 6760 /bin/cat
GNU gdb 6.4.90-debian

[license stuff snipped]

Attaching to program: /bin/cat, process 6760

[snip other stuff that's not interesting now]

(gdb) p close(1)
$1 = 0
(gdb) p creat("/tmp/foo3", 0600)
$2 = 1
(gdb) q
The program is running. Quit anyway (and detach it)? (y or n) y
Detaching from program: /bin/cat, process 6760

The p command in GDB will print the value of an expression, an expression can be a function to call, it can be a system call… So I execute a close() system call and pass file handle 1, then I execute a creat() system call to open a new file. The result of the creat() was 1 which means that it replaced the previous file handle. If I wanted to use the same file for stdout and stderr or if I wanted to replace a file handle with some other number then I would need to call the dup2() system call to achieve that result.

For this example I chose to use creat() instead of open() because there are fewer parameter. The C macros for the flags are not usable from GDB (it doesn’t use C headers) so I would have to read header files to discover this – it’s not that hard to do so but would take more time. Note that 0600 is the octal permission for the owner having read/write access and the group and others having no access. It would also work to use 0 for that parameter and run chmod on the file later on.

After that I verify the result:

ls -l /proc/6760/fd/
total 3
lrwx—— 1 rjc rjc 64 2008-02-27 15:32 0 -> /dev/pts/5
l-wx—— 1 rjc rjc 64 2008-02-27 15:32 1 -> /tmp/foo3 <====
lrwx—— 1 rjc rjc 64 2008-02-27 15:32 2 -> /dev/pts/5

Typing more data in to cat results in the file /tmp/foo3 being appended to.

If you want to close the original session you need to close all file handles for it, open a new device that can be the controlling tty, and then call setsid().

How to change the style of a DatePicker in android?

call like this

 button5.setOnClickListener(new View.OnClickListener() {

 @Override
 public void onClick(View v) {
 // TODO Auto-generated method stub

 DialogFragment dialogfragment = new DatePickerDialogTheme();

 dialogfragment.show(getFragmentManager(), "Theme");

 }
 });

public static class DatePickerDialogTheme extends DialogFragment implements DatePickerDialog.OnDateSetListener{

     @Override
     public Dialog onCreateDialog(Bundle savedInstanceState){
     final Calendar calendar = Calendar.getInstance();
     int year = calendar.get(Calendar.YEAR);
     int month = calendar.get(Calendar.MONTH);
     int day = calendar.get(Calendar.DAY_OF_MONTH);

//for one

//for two 

 DatePickerDialog datepickerdialog = new DatePickerDialog(getActivity(),
 AlertDialog.THEME_DEVICE_DEFAULT_DARK,this,year,month,day);

//for three 
 DatePickerDialog datepickerdialog = new DatePickerDialog(getActivity(),
 AlertDialog.THEME_DEVICE_DEFAULT_LIGHT,this,year,month,day);

// for four

   DatePickerDialog datepickerdialog = new DatePickerDialog(getActivity(),
 AlertDialog.THEME_HOLO_DARK,this,year,month,day);

//for five

 DatePickerDialog datepickerdialog = new DatePickerDialog(getActivity(),
     AlertDialog.THEME_HOLO_LIGHT,this,year,month,day);

//for six

 DatePickerDialog datepickerdialog = new DatePickerDialog(getActivity(),
 AlertDialog.THEME_TRADITIONAL,this,year,month,day);


     return datepickerdialog;
     }

     public void onDateSet(DatePicker view, int year, int month, int day){

     TextView textview = (TextView)getActivity().findViewById(R.id.textView1);

     textview.setText(day + ":" + (month+1) + ":" + year);

     }
     }

follow this it will give you all type date picker style(copy from this)

http://www.android-examples.com/change-datepickerdialog-theme-in-android-using-dialogfragment/

enter image description here

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Extracting extension from filename in Python

With splitext there are problems with files with double extension (e.g. file.tar.gz, file.tar.bz2, etc..)

>>> fileName, fileExtension = os.path.splitext('/path/to/somefile.tar.gz')
>>> fileExtension 
'.gz'

but should be: .tar.gz

The possible solutions are here

Insertion Sort vs. Selection Sort

Both insertion sort and selection sort has an sorted list at the front, and unsorted list at the end, and what the algorithm does is also similar:

  1. Take an element from the unsorted list
  2. Put it into the sorted list

The difference is:

  • Insertion sort take the first element of the unsorted list, and then do compare and swap in the sorted list to make sure the element goes to the right position, the effort is mostly in step #2 for insertion
auto insertion_sort(vector<int>& vs)
{
  for(int i=1; i < vs.size(); ++i)
  {
    for(int j=i; j > 0; --j)
    {
      if(vs[j] < vs[j-1]) swap(vs[j], vs[j-1]);
    }
  }
  return vs;
}
  • Selection sort compare and mark the smallest element of the unsorted list, and then swap it with the first element of the unsorted list, actually include this element as part of the sorted list - the effort is mostly in step #1 for selection
auto selection_sort(vector<int>& vs)
{
  for(int i = 0; i < vs.size(); ++i)
  {
    int iMin = i;
    for(int j=i; j < vs.size(); ++j)
    {
      if(vs[j] < vs[iMin]) iMin = j;
    }
    swap(vs[i], vs[iMin]);
  }
  return vs;
}

Dependency injection with Jersey 2.0

First just to answer a comment in the accepts answer.

"What does bind do? What if I have an interface and an implementation?"

It simply reads bind( implementation ).to( contract ). You can alternative chain .in( scope ). Default scope of PerLookup. So if you want a singleton, you can

bind( implementation ).to( contract ).in( Singleton.class );

There's also a RequestScoped available

Also, instead of bind(Class).to(Class), you can also bind(Instance).to(Class), which will be automatically be a singleton.


Adding to the accepted answer

For those trying to figure out how to register your AbstractBinder implementation in your web.xml (i.e. you're not using a ResourceConfig), it seems the binder won't be discovered through package scanning, i.e.

<servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
<init-param>
    <param-name>jersey.config.server.provider.packages</param-name>
    <param-value>
        your.packages.to.scan
    </param-value>
</init-param>

Or this either

<init-param>
    <param-name>jersey.config.server.provider.classnames</param-name>
    <param-value>
        com.foo.YourBinderImpl
    </param-value>
</init-param>

To get it to work, I had to implement a Feature:

import javax.ws.rs.core.Feature;
import javax.ws.rs.core.FeatureContext;
import javax.ws.rs.ext.Provider;

@Provider
public class Hk2Feature implements Feature {

    @Override
    public boolean configure(FeatureContext context) {
        context.register(new AppBinder());
        return true;
    }
}

The @Provider annotation should allow the Feature to be picked up by the package scanning. Or without package scanning, you can explicitly register the Feature in the web.xml

<servlet>
    <servlet-name>Jersey Web Application</servlet-name>
    <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
    <init-param>
        <param-name>jersey.config.server.provider.classnames</param-name>
        <param-value>
            com.foo.Hk2Feature
        </param-value>
    </init-param>
    ...
    <load-on-startup>1</load-on-startup>
</servlet>

See Also:

and for general information from the Jersey documentation


UPDATE

Factories

Aside from the basic binding in the accepted answer, you also have factories, where you can have more complex creation logic, and also have access to request context information. For example

public class MyServiceFactory implements Factory<MyService> {
    @Context
    private HttpHeaders headers;

    @Override
    public MyService provide() {
        return new MyService(headers.getHeaderString("X-Header"));
    }

    @Override
    public void dispose(MyService service) { /* noop */ }
}

register(new AbstractBinder() {
    @Override
    public void configure() {
        bindFactory(MyServiceFactory.class).to(MyService.class)
                .in(RequestScoped.class);
    }
});

Then you can inject MyService into your resource class.

How to position a div in bottom right corner of a browser?

Try this:

#foo
{
    position: absolute;
    top: 100%;
    right: 0%;
}

How to add "active" class to wp_nav_menu() current menu item (simple way)

Just paste this code into functions.php file:

add_filter('nav_menu_css_class' , 'special_nav_class' , 10 , 2);

function special_nav_class ($classes, $item) {
  if (in_array('current-menu-item', $classes) ){
    $classes[] = 'active ';
  }
  return $classes;
}

More on wordpress.org:

How to get an absolute file path in Python

Update for Python 3.4+ pathlib that actually answers the question:

from pathlib import Path

relative = Path("mydir/myfile.txt")
absolute = relative.absolute()  # absolute is a Path object

If you only need a temporary string, keep in mind that you can use Path objects with all the relevant functions in os.path, including of course abspath:

from os.path import abspath

absolute = abspath(relative)  # absolute is a str object

How do I count columns of a table

I have a more general answer; but I believe it is useful for counting the columns for all tables in a DB:

SELECT table_name, count(*)
FROM information_schema.columns
GROUP BY table_name;

Converting between strings and ArrayBuffers

See here: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Typed_arrays/StringView (a C-like interface for strings based upon the JavaScript ArrayBuffer interface)

How do I select elements of an array given condition?

I like to use np.vectorize for such tasks. Consider the following:

>>> # Arrays
>>> x = np.array([5, 2, 3, 1, 4, 5])
>>> y = np.array(['f','o','o','b','a','r'])

>>> # Function containing the constraints
>>> func = np.vectorize(lambda t: t>1 and t<5)

>>> # Call function on x
>>> y[func(x)]
>>> array(['o', 'o', 'a'], dtype='<U1')

The advantage is you can add many more types of constraints in the vectorized function.

Hope it helps.

Get a filtered list of files in a directory

glob.glob() is definitely the way to do it (as per Ignacio). However, if you do need more complicated matching, you can do it with a list comprehension and re.match(), something like so:

files = [f for f in os.listdir('.') if re.match(r'[0-9]+.*\.jpg', f)]

More flexible, but as you note, less efficient.

Return a `struct` from a function in C

You can assign structs in C. a = b; is valid syntax.

You simply left off part of the type -- the struct tag -- in your line that doesn't work.

Virtual member call in a constructor

Because until the constructor has completed executing, the object is not fully instantiated. Any members referenced by the virtual function may not be initialised. In C++, when you are in a constructor, this only refers to the static type of the constructor you are in, and not the actual dynamic type of the object that is being created. This means that the virtual function call might not even go where you expect it to.

OpenCV NoneType object has no attribute shape

This is because the path of image is wrong or the name of image you write is incorrect .

how to check? first try to print the image using print(img) if it prints 'None' that means you have given wrong image path correct that path and try again.

Rails: call another controller action from a controller

To use one controller from another, do this:

def action_that_calls_one_from_another_controller
  controller_you_want = ControllerYouWant.new
  controller_you_want.request = request
  controller_you_want.response = response
  controller_you_want.action_you_want
end

Add context path to Spring Boot application

server.contextPath=/mainstay

works for me if i had one war file in JBOSS. Among multiple war files where each contain jboss-web.xml it didn't work. I had to put jboss-web.xml inside WEB-INF directory with content

<?xml version="1.0" encoding="UTF-8"?>
<jboss-web xmlns="http://www.jboss.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://www.jboss.com/xml/ns/javaee http://www.jboss.org/j2ee/schema/jboss-web_5_1.xsd">
    <context-root>mainstay</context-root>
</jboss-web>

How to create a date object from string in javascript

Always, for any issue regarding the JavaScript spec in practical, I will highly recommend the Mozilla Developer Network, and their JavaScript reference.

As it states in the topic of the Date object about the argument variant you use:

new Date(year, month, day [, hour, minute, second, millisecond ])

And about the months parameter:

month Integer value representing the month, beginning with 0 for January to 11 for December.

Clearly, then, you should use the month number 10 for November.

P.S.: The reason why I recommend the MDN is the correctness, good explanation of things, examples, and browser compatibility chart.

Eclipse: "'Periodic workspace save.' has encountered a pro?blem."

Agree with @J-Dizzle,

I am a beginner in web-development and had a hard time solving this today. Had similar problems when I was creating a SpringBoot project in STS. Tried most of the solutions mentioned but they didn't work. Tried removing .metadata folder and re-building my springboot project but still nothing worked.

NOTE : I had multiple workspace in STS and this error occurred after migrating a project from one workspace to another.

Solution : All you need to do is restart your eclipse/STS IDE and it will work just fine.

How to check if a python module exists without importing it

There is no way to reliably check if "dotted module" is importable without importing its parent package. Saying this, there are many solutions to problem "how to check if Python module exists".

Below solution address the problem that imported module can raise ImportError even it exists. We want to distinguish that situation from such in which module does not exist.

Python 2:

import importlib
import pkgutil
import sys

def find_module(full_module_name):
    """
    Returns module object if module `full_module_name` can be imported. 

    Returns None if module does not exist. 

    Exception is raised if (existing) module raises exception during its import.
    """
    module = sys.modules.get(full_module_name)
    if module is None:
        module_path_tail = full_module_name.split('.')
        module_path_head = []
        loader = True
        while module_path_tail and loader:
            module_path_head.append(module_path_tail.pop(0))
            module_name = ".".join(module_path_head)
            loader = bool(pkgutil.find_loader(module_name))
            if not loader:
                # Double check if module realy does not exist
                # (case: full_module_name == 'paste.deploy')
                try:
                    importlib.import_module(module_name)
                except ImportError:
                    pass
                else:
                    loader = True
        if loader:
            module = importlib.import_module(full_module_name)
    return module

Python 3:

import importlib

def find_module(full_module_name):
    """
    Returns module object if module `full_module_name` can be imported. 

    Returns None if module does not exist. 

    Exception is raised if (existing) module raises exception during its import.
    """
    try:
        return importlib.import_module(full_module_name)
    except ImportError as exc:
        if not (full_module_name + '.').startswith(exc.name + '.'):
            raise

How to extract an assembly from the GAC?

Easy way I have found is to open the command prompt and browse through the folder you mention until you find the DLL you want - you can then user the copy command to get it out. Windows Explorer has a "helpful" special view of this folder.

Function to calculate R2 (R-squared) in R

You can also use the summary for linear models:

summary(lm(obs ~ mod, data=df))$r.squared 

UITableView set to static cells. Is it possible to hide some of the cells programmatically?

Solution from k06a (https://github.com/k06a/ABStaticTableViewController) is better because it hides whole section including cells headers and footers, where this solution (https://github.com/peterpaulis/StaticDataTableViewController) hides everything except footer.

EDIT

I just found solution if you want to hide footer in StaticDataTableViewController. This is what you need to copy in StaticTableViewController.m file:

- (NSString *)tableView:(UITableView *)tableView titleForFooterInSection:(NSInteger)section {
    if ([tableView.dataSource tableView:tableView numberOfRowsInSection:section] == 0) {
        return nil;
    } else {
        return [super tableView:tableView titleForFooterInSection:section];
    }
}

- (CGFloat)tableView:(UITableView *)tableView heightForFooterInSection:(NSInteger)section {

    CGFloat height = [super tableView:tableView heightForFooterInSection:section];

    if (self.originalTable == nil) {
        return height;
    }

    if (!self.hideSectionsWithHiddenRows) {
        return height;
    }

    OriginalSection * os = self.originalTable.sections[section];
    if ([os numberOfVissibleRows] == 0) {
       //return 0;
        return CGFLOAT_MIN;
    } else {
        return height;
    }

    //return 0;
    return CGFLOAT_MIN;
}

Asynchronously wait for Task<T> to complete with timeout

Another way of solving this problem is using Reactive Extensions:

public static Task TimeoutAfter(this Task task, TimeSpan timeout, IScheduler scheduler)
{
        return task.ToObservable().Timeout(timeout, scheduler).ToTask();
}

Test up above using below code in your unit test, it works for me

TestScheduler scheduler = new TestScheduler();
Task task = Task.Run(() =>
                {
                    int i = 0;
                    while (i < 5)
                    {
                        Console.WriteLine(i);
                        i++;
                        Thread.Sleep(1000);
                    }
                })
                .TimeoutAfter(TimeSpan.FromSeconds(5), scheduler)
                .ContinueWith(t => { }, TaskContinuationOptions.OnlyOnFaulted);

scheduler.AdvanceBy(TimeSpan.FromSeconds(6).Ticks);

You may need the following namespace:

using System.Threading.Tasks;
using System.Reactive.Subjects;
using System.Reactive.Linq;
using System.Reactive.Threading.Tasks;
using Microsoft.Reactive.Testing;
using System.Threading;
using System.Reactive.Concurrency;

Centering elements in jQuery Mobile

In the situation where you are NOT going to use this over and over (i.e. not needed in your style sheet), inline style statements usually work anywhere they would work inyour style sheet. E.g:

<div data-role="controlgroup" data-type="horizontal" style="text-align:center;">

Is there a better way to iterate over two lists, getting one element from each list for each iteration?

Iterating through elements of two lists simultaneously is known as zipping, and python provides a built in function for it, which is documented here.

>>> x = [1, 2, 3]
>>> y = [4, 5, 6]
>>> zipped = zip(x, y)
>>> zipped
[(1, 4), (2, 5), (3, 6)]
>>> x2, y2 = zip(*zipped)
>>> x == list(x2) and y == list(y2)
True

[Example is taken from pydocs]

In your case, it will be simply:

for (lat, lon) in zip(latitudes, longitudes):
    ... process lat and lon

PHP Configuration: It is not safe to rely on the system's timezone settings

Open your .htaccess file , add this line to the file, save, and try again :

php_value date.timezone "America/Sao_Paulo"

This works for me.

How to check if string contains Latin characters only?

I'm surprised that the answers here got so many upvotes when none of them really answer the question. Here's how to make sure that ONLY LATIN characters are in a given string.

const hasOnlyLetters = !!value.match(/^[a-z]*$/i);

The !! takes transforms something that's not boolean into a boolean value. (It's exactly the same as applying a ! twice, and in fact you can use as many ! as you'd like to toggle the truthiness multiple times.)

As for the RegEx, here's the breakdown.

  • /.../i The delimiter is a / and the i means to assess the statement in a case-insensitive fashion.
  • ^...$ The ^ means to look at the very beginning of a string. The $ means to look at the end of the string, and when used together, it means to consider the entire string. You can add more to the RegEx outside of these boundaries for things like appending/prepending a required suffix or prefix.
  • [a-z]*This part says to look for all lowercase letters. (The case-insensitive modifier means that we don't need to look at uppercase letters, too.) The * at the end says that we should match whats in the brackets any number of times. That way "abc" will match instead of just "a" or "b", and so forth.

Get installed applications in a system

I agree that enumerating through the registry key is the best way.

Note, however, that the key given, @"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall", will list all applications in a 32-bit Windows installation, and 64-bit applications in a Windows 64-bit installation.

In order to also see 32-bit applications installed on a Windows 64-bit installation, you would also need to enumeration the key @"SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall".

Is there a way to delete created variables, functions, etc from the memory of the interpreter?

If you are in an interactive environment like Jupyter or ipython you might be interested in clearing unwanted var's if they are getting heavy.

The magic-commands reset and reset_selective is vailable on interactive python sessions like ipython and Jupyter

1) reset

reset Resets the namespace by removing all names defined by the user, if called without arguments.

in and the out parameters specify whether you want to flush the in/out caches. The directory history is flushed with the dhist parameter.

reset in out

Another interesting one is array that only removes numpy Arrays:

reset array

2) reset_selective

Resets the namespace by removing names defined by the user. Input/Output history are left around in case you need them.

Clean Array Example:

In [1]: import numpy as np
In [2]: littleArray = np.array([1,2,3,4,5])
In [3]: who_ls
Out[3]: ['littleArray', 'np']
In [4]: reset_selective -f littleArray
In [5]: who_ls
Out[5]: ['np']

Source: http://ipython.readthedocs.io/en/stable/interactive/magics.html

Add marker to Google Map on Click

@Chaibi Alaa, To make the user able to add only once, and move the marker; You can set the marker on first click and then just change the position on subsequent clicks.

var marker;

google.maps.event.addListener(map, 'click', function(event) {
   placeMarker(event.latLng);
});


function placeMarker(location) {

    if (marker == null)
    {
          marker = new google.maps.Marker({
             position: location,
             map: map
          }); 
    } 
    else 
    {
        marker.setPosition(location); 
    } 
}

How to restore PostgreSQL dump file into Postgres databases?

By using pg_restore command you can restore postgres database

First open terminal type

sudo su postgres

Create new database

createdb [database name] -O [owner]

createdb test_db [-O openerp]

pg_restore -d [Database Name] [path of dump file]

pg_restore -d test_db /home/sagar/Download/sample_dbump

Wait for completion of database restoring.

Remember that dump file should have read, write, execute access, so for that you can apply chmod command

Remove an item from array using UnderscoreJS

Underscore has a _without() method perfect for removing an item from an array, especially if you have the object to remove.

Returns a copy of the array with all instances of the values removed.

_.without(["bob", "sam", "fred"], "sam");

=> ["bob", "fred"]

Works with more complex objects too.

var bob = { Name: "Bob", Age: 35 };
var sam = { Name: "Sam", Age: 19 };
var fred = { Name: "Fred", Age: 50 };

var people = [bob, sam, fred]

_.without(people, sam);

=> [{ Name: "Bob", Age: 35 }, { Name: "Fred", Age: 50 }];

If you don't have the item to remove, just a property of it, you can use _.findWhere and then _.without.

Getting file size in Python?

You may use os.stat() function, which is a wrapper of system call stat():

import os

def getSize(filename):
    st = os.stat(filename)
    return st.st_size

Detect changes in the DOM

Ultimate approach so far, with smallest code:

(IE9+, FF, Webkit)

Using MutationObserver and falling back to the deprecated Mutation events if needed:
(Example below if only for DOM changes concerning nodes appended or removed)

_x000D_
_x000D_
var observeDOM = (function(){
  var MutationObserver = window.MutationObserver || window.WebKitMutationObserver;

  return function( obj, callback ){
    if( !obj || obj.nodeType !== 1 ) return; 

    if( MutationObserver ){
      // define a new observer
      var mutationObserver = new MutationObserver(callback)

      // have the observer observe foo for changes in children
      mutationObserver.observe( obj, { childList:true, subtree:true })
      return mutationObserver
    }
    
    // browser support fallback
    else if( window.addEventListener ){
      obj.addEventListener('DOMNodeInserted', callback, false)
      obj.addEventListener('DOMNodeRemoved', callback, false)
    }
  }
})()


//------------< DEMO BELOW >----------------

// add item
var itemHTML = "<li><button>list item (click to delete)</button></li>",
    listElm = document.querySelector('ol');

document.querySelector('body > button').onclick = function(e){
  listElm.insertAdjacentHTML("beforeend", itemHTML);
}

// delete item
listElm.onclick = function(e){
  if( e.target.nodeName == "BUTTON" )
    e.target.parentNode.parentNode.removeChild(e.target.parentNode);
}
    
// Observe a specific DOM element:
observeDOM( listElm, function(m){ 
   var addedNodes = [], removedNodes = [];

   m.forEach(record => record.addedNodes.length & addedNodes.push(...record.addedNodes))
   
   m.forEach(record => record.removedNodes.length & removedNodes.push(...record.removedNodes))

  console.clear();
  console.log('Added:', addedNodes, 'Removed:', removedNodes);
});


// Insert 3 DOM nodes at once after 3 seconds
setTimeout(function(){
   listElm.removeChild(listElm.lastElementChild);
   listElm.insertAdjacentHTML("beforeend", Array(4).join(itemHTML));
}, 3000);
_x000D_
<button>Add Item</button>
<ol>
  <li><button>list item (click to delete)</button></li>
  <li><button>list item (click to delete)</button></li>
  <li><button>list item (click to delete)</button></li>
  <li><button>list item (click to delete)</button></li>
  <li><em>&hellip;More will be added after 3 seconds&hellip;</em></li>
</ol>
_x000D_
_x000D_
_x000D_

What's the difference between Cache-Control: max-age=0 and no-cache?

I'm hardly a caching expert, but Mark Nottingham is. Here are his caching docs. He also has excellent links in the References section.

Based on my reading of those docs, it looks like max-age=0 could allow the cache to send a cached response to requests that came in at the "same time" where "same time" means close enough together they look simultaneous to the cache, but no-cache would not.

C++ correct way to return pointer to array from function

Your code as it stands is correct but I am having a hard time figuring out how it could/would be used in a real world scenario. With that said, please be aware of a few caveats when returning pointers from functions:

  • When you create an array with syntax int arr[5];, it's allocated on the stack and is local to the function.
  • C++ allows you to return a pointer to this array, but it is undefined behavior to use the memory pointed to by this pointer outside of its local scope. Read this great answer using a real world analogy to get a much clear understanding than what I could ever explain.
  • You can still use the array outside the scope if you can guarantee that memory of the array has not be purged. In your case this is true when you pass arr to test().
  • If you want to pass around pointers to a dynamically allocated array without worrying about memory leaks, you should do some reading on std::unique_ptr/std::shared_ptr<>.

Edit - to answer the use-case of matrix multiplication

You have two options. The naive way is to use std::unique_ptr/std::shared_ptr<>. The Modern C++ way is to have a Matrix class where you overload operator * and you absolutely must use the new rvalue references if you want to avoid copying the result of the multiplication to get it out of the function. In addition to having your copy constructor, operator = and destructor, you also need to have move constructor and move assignment operator. Go through the questions and answers of this search to gain more insight on how to achieve this.

Edit 2 - answer to appended question

int* test (int a[5], int b[5]) {
    int *c = new int[5];
    for (int i = 0; i < 5; i++) c[i] = a[i]+b[i];
    return c;
}

If you are using this as int *res = test(a,b);, then sometime later in your code, you should call delete []res to free the memory allocated in the test() function. You see now the problem is it is extremely hard to manually keep track of when to make the call to delete. Hence the approaches on how to deal with it where outlined in the answer.

How to populate/instantiate a C# array with a single value?

If you are on .NET Core, .NET Standard >= 2.1, or depend on the System.Memory package, you can also use the Span<T>.Fill() method:

var valueToFill = 165;
var data = new int[100];

data.AsSpan().Fill(valueToFill);

// print array content
for (int i = 0; i < data.Length; i++)
{
    Console.WriteLine(data[i]);
}

https://dotnetfiddle.net/UsJ9bu

Failure [INSTALL_FAILED_ALREADY_EXISTS] when I tried to update my application

You are getting that error because an application with a package name same as your application already exists. If you are sure that you have not installed the same application before, change the package name and try.

Else wise, here is what you can do:

  1. Uninstall the application from the device: Go to Settings -> Manage Applications and choose Uninstall OR
  2. Uninstall the app using adb command line interface: type adb uninstall After you are done with this step, try installing the application again.

Associating enums with strings in C#

A small tweak to Glennular Extension method, so you could use the extension on other things than just ENUM's;

using System;
using System.ComponentModel;
namespace Extensions {
    public static class T_Extensions {
        /// <summary>
        /// Gets the Description Attribute Value
        /// </summary>
        /// <typeparam name="T">Entity Type</typeparam>
        /// <param name="val">Variable</param>
        /// <returns>The value of the Description Attribute or an Empty String</returns>
        public static string Description<T>(this T t) {
            DescriptionAttribute[] attributes = (DescriptionAttribute[])t.GetType().GetField(t.ToString()).GetCustomAttributes(typeof(DescriptionAttribute), false);
            return attributes.Length > 0 ? attributes[0].Description : string.Empty;
        }
    }
}

Or Using Linq

using System;
using System.ComponentModel;
using System.Linq;

namespace Extensions {


public static class T_Extensions {
        public static string Description<T>(this T t) =>
            ((DescriptionAttribute[])t
            ?.GetType()
            ?.GetField(t?.ToString())
            ?.GetCustomAttributes(typeof(DescriptionAttribute), false))
            ?.Select(a => a?.Description)
            ?.FirstOrDefault() 
            ?? string.Empty;  
    }
}

How to split a string into a list?

shlex has a .split() function. It differs from str.split() in that it does not preserve quotes and treats a quoted phrase as a single word:

>>> import shlex
>>> shlex.split("sudo echo 'foo && bar'")
['sudo', 'echo', 'foo && bar']

NB: it works well for Unix-like command line strings. It doesn't work for natural-language processing.

Php, wait 5 seconds before executing an action

In Jan2018 the only solution worked for me:

<?php

if (ob_get_level() == 0) ob_start();
for ($i = 0; $i<10; $i++){

    echo "<br> Line to show.";
    echo str_pad('',4096)."\n";    

    ob_flush();
    flush();
    sleep(2);
}

echo "Done.";

ob_end_flush();

?>

How to convert DATE to UNIX TIMESTAMP in shell script on MacOS

man date on OSX has this example

date -j -f "%a %b %d %T %Z %Y" "`date`" "+%s"

Which I think does what you want.

You can use this for a specific date

date -j -f "%a %b %d %T %Z %Y" "Tue Sep 28 19:35:15 EDT 2010" "+%s"

Or use whatever format you want.

first-child and last-child with IE8

Since :last-child is a CSS3 pseudo-class, it is not supported in IE8. I believe :first-child is supported, as it's defined in the CSS2.1 specification.

One possible solution is to simply give the last child a class name and style that class.

Another would be to use JavaScript. jQuery makes this particularly easy as it provides a :last-child pseudo-class which should work in IE8. Unfortunately, that could result in a flash of unstyled content while the DOM loads.

DLL References in Visual C++

The additional include directories are relative to the project dir. This is normally the dir where your project file, *.vcproj, is located. I guess that in your case you have to add just "include" to your include and library directories.

If you want to be sure what your project dir is, you can check the value of the $(ProjectDir) macro. To do that go to "C/C++ -> Additional Include Directories", press the "..." button and in the pop-up dialog press "Macros>>".

How to format numbers by prepending 0 to single-digit numbers?

This is simple and works pretty well:

function twoDigit(number) {
  var twodigit = number >= 10 ? number : "0"+number.toString();
  return twodigit;
}

How can I have grep not print out 'No such file or directory' errors?

Errors like that are usually sent to the "standard error" stream, which you can pipe to a file or just make disappear on most commands:

grep pattern * -R -n 2>/dev/null

Build fat static library (device + simulator) using Xcode and SDK 4+

IOS 10 Update:

I had a problem with building the fatlib with iphoneos10.0 because the regular expression in the script only expects 9.x and lower and returns 0.0 for ios 10.0

to fix this just replace

SDK_VERSION=$(echo ${SDK_NAME} | grep -o '.\{3\}$')

with

SDK_VERSION=$(echo ${SDK_NAME} | grep -o '[\\.0-9]\{3,4\}$')

Laravel 5.1 - Checking a Database Connection

Another Approach:

When Laravel tries to connect to database, if the connection fails or if it finds any errors it will return a PDOException error. We can catch this error and redirect the action

Add the following code in the app/filtes.php file.

App::error(function(PDOException $exception)
{
    Log::error("Error connecting to database: ".$exception->getMessage());

    return "Error connecting to database";
});

Hope this is helpful.

Angular JS break ForEach

Normally there is no way to break an "each" loop in javascript. What can be done usually is to use "short circuit" method.

_x000D_
_x000D_
    array.forEach(function(item) {_x000D_
      // if the condition is not met, move on to the next round of iteration._x000D_
      if (!condition) return;_x000D_
_x000D_
      // if the condition is met, do your logic here_x000D_
      console.log('do stuff.')_x000D_
    }
_x000D_
_x000D_
_x000D_

Combine two columns of text in pandas dataframe

Here is my summary of the above solutions to concatenate / combine two columns with int and str value into a new column, using a separator between the values of columns. Three solutions work for this purpose.

# be cautious about the separator, some symbols may cause "SyntaxError: EOL while scanning string literal".
# e.g. ";;" as separator would raise the SyntaxError

separator = "&&" 

# pd.Series.str.cat() method does not work to concatenate / combine two columns with int value and str value. This would raise "AttributeError: Can only use .cat accessor with a 'category' dtype"

df["period"] = df["Year"].map(str) + separator + df["quarter"]
df["period"] = df[['Year','quarter']].apply(lambda x : '{} && {}'.format(x[0],x[1]), axis=1)
df["period"] = df.apply(lambda x: f'{x["Year"]} && {x["quarter"]}', axis=1)

How to succinctly write a formula with many variables from a data frame?

I build this solution, reformulate does not take care if variable names have white spaces.

add_backticks = function(x) {
    paste0("`", x, "`")
}

x_lm_formula = function(x) {
    paste(add_backticks(x), collapse = " + ")
}

build_lm_formula = function(x, y){
    if (length(y)>1){
        stop("y needs to be just one variable")
    }
    as.formula(        
        paste0("`",y,"`", " ~ ", x_lm_formula(x))
    )
}

# Example
df <- data.frame(
    y = c(1,4,6), 
    x1 = c(4,-1,3), 
    x2 = c(3,9,8), 
    x3 = c(4,-4,-2)
    )

# Model Specification
columns = colnames(df)
y_cols = columns[1]
x_cols = columns[2:length(columns)]
formula = build_lm_formula(x_cols, y_cols)
formula
# output
# "`y` ~ `x1` + `x2` + `x3`"

# Run Model
lm(formula = formula, data = df)
# output
Call:
    lm(formula = formula, data = df)

Coefficients:
    (Intercept)           x1           x2           x3  
        -5.6316       0.7895       1.1579           NA  

```

SQL Server Error : String or binary data would be truncated

You're trying to write more data than a specific column can store. Check the sizes of the data you're trying to insert against the sizes of each of the fields.

In this case transaction_status is a varchar(10) and you're trying to store 19 characters to it.

Change border color on <select> HTML form

As Diodeus stated, IE doesn't allow anything but the default border for <select> elements. However, I know of two hacks to achieve a similar effect :

  1. Use a DIV that is placed absolutely at the same position as the dropdown and set it's borders. It will appear that the dropdown has a border.

  2. Use a Javascript solution, for instance, the one provided here.

It may however prove to be too much effort, so you should evaluate if you really require the border.

How to write text on a image in windows using python opencv2

This is indeed a bit of an annoying problem. For python 2.x.x you use:

cv2.CV_FONT_HERSHEY_SIMPLEX

and for Python 3.x.x:

cv2.FONT_HERSHEY_SIMPLEX

I recommend using a autocomplete environment(pyscripter or scipy for example). If you lookup example code, make sure they use the same version of Python(if they don't make sure you change the code).

Can't install nuget package because of "Failed to initialize the PowerShell host"

after trying all the suggested solution nothing worked on VS 2015 update 2

deleting the package folder from the solution folder and restoring it from visual studio worked for me

ImportError: No module named mysql.connector using Python2

If you have this error on PYCHARM: ImportError: No module named mysql.connector

Try this solution: Open Pycharm go to File->Settings-> Project->Python Interpreter inside Pycharm, Then press + icon to install mysql-connector. Problem solved!

How do I fire an event when a iframe has finished loading in jQuery?

If you can expect the browser's open/save interface to pop up for the user once the download is complete, then you can run this when you start the download:

$( document ).blur( function () {
    // Your code here...
});

When the dialogue pops up on top of the page, the blur event will trigger.

Calculate execution time of a SQL query?

Well, If you really want to do it in your DB there is a more accurate way as given in MSDN:

SET STATISTICS TIME ON

You can read this information from your application as well.

How do you show animated GIFs on a Windows Form (c#)

I had the same issue and came across different solutions by implementing which I used to face several different issues. Finally, below is what I put some pieces from different posts together which worked for me as expected.

private void btnCompare_Click(object sender, EventArgs e)
{
    ThreadStart threadStart = new ThreadStart(Execution);
    Thread thread = new Thread(threadStart);
    thread.SetApartmentState(ApartmentState.STA);
    thread.Start();
}

Here is the Execution method that also carries invoking the PictureBox control:

private void Execution()
{
    btnCompare.Invoke((MethodInvoker)delegate { pictureBox1.Visible = true; });
    Application.DoEvents();

    // Your main code comes here . . .

    btnCompare.Invoke((MethodInvoker)delegate { pictureBox1.Visible = false; });
}

Keep in mind, the PictureBox is invisible from Properties Window or do below:

private void ComparerForm_Load(object sender, EventArgs e)
{
    pictureBox1.Visible = false;
}

Node.js, can't open files. Error: ENOENT, stat './path/to/file'

Here the code to use your app.js

input specifies file name

res.download(__dirname+'/'+input);

Using prepared statements with JDBCTemplate

Try the following:

PreparedStatementCreator creator = new PreparedStatementCreator() {
    @Override
    public PreparedStatement createPreparedStatement(Connection con) throws SQLException {
        PreparedStatement updateSales = con.prepareStatement(
        "UPDATE COFFEES SET SALES = ? WHERE COF_NAME LIKE ? ");
        updateSales.setInt(1, 75); 
        updateSales.setString(2, "Colombian"); 
        return updateSales;
    }
};

Difference between logical addresses, and physical addresses?

Logical address:- Logical address generated by the CPU . when we are give the problem to the computer then our computer pass the problem to the processor through logical address , which we are not seen this address called logical address .

Physical address :- when our processor create process and solve our problem then we store data in secondary memory through address called physical address

Is Eclipse the best IDE for Java?

IntelliJ is good one but its not free!!Then NetBeans is also a good option.Also if you are IBM suite WSAD is good

Not showing placeholder for input type="date" field

It may not be appropriate... but it helped me.

_x000D_
_x000D_
<input placeholder="Date" class="textbox-n" type="text" onfocus="(this.type='date')" id="date">
_x000D_
_x000D_
_x000D_

Instantiating a generic class in Java

Here's a rather contrived way to do it without explicitly using an constructor argument. You need to extend a parameterized abstract class.

public class Test {   
    public static void main(String [] args) throws Exception {
        Generic g = new Generic();
        g.initParameter();
    }
}

import java.lang.reflect.ParameterizedType;
public abstract class GenericAbstract<T extends Foo> {
    protected T parameter;

    @SuppressWarnings("unchecked")
    void initParameter() throws Exception, ClassNotFoundException, 
        InstantiationException {
        // Get the class name of this instance's type.
        ParameterizedType pt
            = (ParameterizedType) getClass().getGenericSuperclass();
        // You may need this split or not, use logging to check
        String parameterClassName
            = pt.getActualTypeArguments()[0].toString().split("\\s")[1];
        // Instantiate the Parameter and initialize it.
        parameter = (T) Class.forName(parameterClassName).newInstance();
    }
}

public class Generic extends GenericAbstract<Foo> {
}

public class Foo {
    public Foo() {
        System.out.println("Foo constructor...");
    }
}

Conveniently map between enum and int / String

given:

public enum BonusType { MONTHLY(0), YEARLY(1), ONE_OFF(2) }

BonusType bonus = YEARLY;

System.out.println(bonus.Ordinal() + ":" + bonus)

Output: 1:YEARLY

Update select2 data without rebuilding the control

select2 v3.x

If you have local array with options (received by ajax call), i think you should use data parameter as function returning results for select box:

var pills = [{id:0, text: "red"}, {id:1, text: "blue"}]; 

$('#selectpill').select2({
    placeholder: "Select a pill",
    data: function() { return {results: pills}; }
});

$('#uppercase').click(function() {
    $.each(pills, function(idx, val) {
        pills[idx].text = val.text.toUpperCase();
    });
});
$('#newresults').click(function() {
    pills = [{id:0, text: "white"}, {id:1, text: "black"}];
});

FIDDLE: http://jsfiddle.net/RVnfn/576/

In case if you customize select2 interface with buttons, just call updateResults (this method not allowed to call from outsite of select2 object but you can add it to allowedMethods array in select2 if you need to) method after updateting data array(pills in example).


select2 v4: custom data adapter

Custom data adapter with additional updateOptions (its unclear why original ArrayAdapter lacks this functionality) method can be used to dynamically update options list (all options in this example):

$.fn.select2.amd.define('select2/data/customAdapter',
    ['select2/data/array', 'select2/utils'],
    function (ArrayAdapter, Utils) {
        function CustomDataAdapter ($element, options) {
            CustomDataAdapter.__super__.constructor.call(this, $element, options);
        }
        Utils.Extend(CustomDataAdapter, ArrayAdapter);
        CustomDataAdapter.prototype.updateOptions = function (data) {
            this.$element.find('option').remove(); // remove all options
            this.addOptions(this.convertToOptions(data));
        }        
        return CustomDataAdapter;
    }
);

var customAdapter = $.fn.select2.amd.require('select2/data/customAdapter');

var sel = $('select').select2({
    dataAdapter: customAdapter,
    data: pills
});

$('#uppercase').click(function() {
    $.each(pills, function(idx, val) {
        pills[idx].text = val.text.toUpperCase();
    });
    sel.data('select2').dataAdapter.updateOptions(pills);
});

FIDDLE: https://jsfiddle.net/xu48n36c/1/


select2 v4: ajax transport function

in v4 you can define custom transport method that can work with local data array (thx @Caleb_Kiage for example, i've played with it without succes)

docs: https://select2.github.io/options.html#can-an-ajax-plugin-other-than-jqueryajax-be-used

Select2 uses the transport method defined in ajax.transport to send requests to your API. By default, this transport method is jQuery.ajax but this can be changed.

$('select').select2({
    ajax: {
        transport: function(params, success, failure) {
            var items = pills;
            // fitering if params.data.q available
            if (params.data && params.data.q) {
                items = items.filter(function(item) {
                    return new RegExp(params.data.q).test(item.text);
                });
            }
            var promise = new Promise(function(resolve, reject) {
                resolve({results: items});
            });
            promise.then(success);
            promise.catch(failure);
        }
    }
});

BUT with this method you need to change ids of options if text of option in array changes - internal select2 dom option element list did not modified. If id of option in array stay same - previous saved option will be displayed instead of updated from array! That is not problem if array modified only by adding new items to it - ok for most common cases.

FIDDLE: https://jsfiddle.net/xu48n36c/3/

What is function overloading and overriding in php?

Overloading is defining functions that have similar signatures, yet have different parameters. Overriding is only pertinent to derived classes, where the parent class has defined a method and the derived class wishes to override that method.

In PHP, you can only overload methods using the magic method __call.

An example of overriding:

<?php

class Foo {
   function myFoo() {
      return "Foo";
   }
}

class Bar extends Foo {
   function myFoo() {
      return "Bar";
   }
}

$foo = new Foo;
$bar = new Bar;
echo($foo->myFoo()); //"Foo"
echo($bar->myFoo()); //"Bar"
?>

Batch files - number of command line arguments

If the number of arguments should be an exact number (less or equal to 9), then this is a simple way to check it:

if "%2" == "" goto args_count_wrong
if "%3" == "" goto args_count_ok

:args_count_wrong
echo I need exactly two command line arguments
exit /b 1

:args_count_ok

How can building a heap be O(n) time complexity?

Intuitively:

"The complexity should be O(nLog n)... for each item we "heapify", it has the potential to have to filter down once for each level for the heap so far (which is log n levels)."

Not quite. Your logic does not produce a tight bound -- it over estimates the complexity of each heapify. If built from the bottom up, insertion (heapify) can be much less than O(log(n)). The process is as follows:

( Step 1 ) The first n/2 elements go on the bottom row of the heap. h=0, so heapify is not needed.

( Step 2 ) The next n/22 elements go on the row 1 up from the bottom. h=1, heapify filters 1 level down.

( Step i ) The next n/2i elements go in row i up from the bottom. h=i, heapify filters i levels down.

( Step log(n) ) The last n/2log2(n) = 1 element goes in row log(n) up from the bottom. h=log(n), heapify filters log(n) levels down.

NOTICE: that after step one, 1/2 of the elements (n/2) are already in the heap, and we didn't even need to call heapify once. Also, notice that only a single element, the root, actually incurs the full log(n) complexity.


Theoretically:

The Total steps N to build a heap of size n, can be written out mathematically.

At height i, we've shown (above) that there will be n/2i+1 elements that need to call heapify, and we know heapify at height i is O(i). This gives:

enter image description here

The solution to the last summation can be found by taking the derivative of both sides of the well known geometric series equation:

enter image description here

Finally, plugging in x = 1/2 into the above equation yields 2. Plugging this into the first equation gives:

enter image description here

Thus, the total number of steps is of size O(n)

JavaScript before leaving the page

Just a bit more helpful, enable and disable

$(window).on('beforeunload.myPluginName', false); // or use function() instead of false
$(window).off('beforeunload.myPluginName');

Python Pandas: Get index of rows which column matches certain value

Simple way is to reset the index of the DataFrame prior to filtering:

df_reset = df.reset_index()
df_reset[df_reset['BoolCol']].index.tolist()

Bit hacky, but it's quick!

AttributeError: Module Pip has no attribute 'main'

It appears that pip did a refactor and moved main to internal. There is a comprehensive discussion about it here: https://github.com/pypa/pip/issues/5240

A workaround for me was to change

import pip
pip.main(...)

to

from pip._internal import main
main(...)

I recommend reading through the discussion, I'm not sure this is the best approach, but it worked for my purposes.

The module ".dll" was loaded but the entry-point was not found

I had this problem and

dumpbin /exports mydll.dll

and

depends mydll.dll

showed 'DllRegisterServer'.

The problem was that there was another DLL in the system that had the same name. After renaming mydll the registration succeeded.

Markdown `native` text alignment

I found pretty useful to use latex syntax on jupyter notebooks cells, like:

![good-boy](https://i.imgur.com/xtoLyW2.jpg  "Good boy on boat")

$$\text{This is some centered text}$$

ASP MVC href to a controller/view

Here '~' refers to the root directory ,where Home is controller and Download_Excel_File is actionmethod

 <a href="~/Home/Download_Excel_File" />

Good Hash Function for Strings

If you want to see the industry standard implementations, I'd look at java.security.MessageDigest.

"Message digests are secure one-way hash functions that take arbitrary-sized data and output a fixed-length hash value."

How to convert java.util.Date to java.sql.Date?

You can use this method to convert util date to sql date,

DateUtilities.convertUtilDateToSql(java.util.Date)

Different ways of loading a file as an InputStream

There are subtle differences as to how the fileName you are passing is interpreted. Basically, you have 2 different methods: ClassLoader.getResourceAsStream() and Class.getResourceAsStream(). These two methods will locate the resource differently.

In Class.getResourceAsStream(path), the path is interpreted as a path local to the package of the class you are calling it from. For example calling, String.class.getResourceAsStream("myfile.txt") will look for a file in your classpath at the following location: "java/lang/myfile.txt". If your path starts with a /, then it will be considered an absolute path, and will start searching from the root of the classpath. So calling String.class.getResourceAsStream("/myfile.txt") will look at the following location in your class path ./myfile.txt.

ClassLoader.getResourceAsStream(path) will consider all paths to be absolute paths. So calling String.class.getClassLoader().getResourceAsStream("myfile.txt") and String.class.getClassLoader().getResourceAsStream("/myfile.txt") will both look for a file in your classpath at the following location: ./myfile.txt.

Everytime I mention a location in this post, it could be a location in your filesystem itself, or inside the corresponding jar file, depending on the Class and/or ClassLoader you are loading the resource from.

In your case, you are loading the class from an Application Server, so your should use Thread.currentThread().getContextClassLoader().getResourceAsStream(fileName) instead of this.getClass().getClassLoader().getResourceAsStream(fileName). this.getClass().getResourceAsStream() will also work.

Read this article for more detailed information about that particular problem.


Warning for users of Tomcat 7 and below

One of the answers to this question states that my explanation seems to be incorrect for Tomcat 7. I've tried to look around to see why that would be the case.

So I've looked at the source code of Tomcat's WebAppClassLoader for several versions of Tomcat. The implementation of findResource(String name) (which is utimately responsible for producing the URL to the requested resource) is virtually identical in Tomcat 6 and Tomcat 7, but is different in Tomcat 8.

In versions 6 and 7, the implementation does not attempt to normalize the resource name. This means that in these versions, classLoader.getResourceAsStream("/resource.txt") may not produce the same result as classLoader.getResourceAsStream("resource.txt") event though it should (since that what the Javadoc specifies). [source code]

In version 8 though, the resource name is normalized to guarantee that the absolute version of the resource name is the one that is used. Therefore, in Tomcat 8, the two calls described above should always return the same result. [source code]

As a result, you have to be extra careful when using ClassLoader.getResourceAsStream() or Class.getResourceAsStream() on Tomcat versions earlier than 8. And you must also keep in mind that class.getResourceAsStream("/resource.txt") actually calls classLoader.getResourceAsStream("resource.txt") (the leading / is stripped).

how to use JSON.stringify and json_decode() properly

I don't how this works, but it worked.

$post_data = json_decode(json_encode($_POST['request_key']));

Java verify void method calls n times with Mockito

The necessary method is Mockito#verify:

public static <T> T verify(T mock,
                           VerificationMode mode)

mock is your mocked object and mode is the VerificationMode that describes how the mock should be verified. Possible modes are:

verify(mock, times(5)).someMethod("was called five times");
verify(mock, never()).someMethod("was never called");
verify(mock, atLeastOnce()).someMethod("was called at least once");
verify(mock, atLeast(2)).someMethod("was called at least twice");
verify(mock, atMost(3)).someMethod("was called at most 3 times");
verify(mock, atLeast(0)).someMethod("was called any number of times"); // useful with captors
verify(mock, only()).someMethod("no other method has been called on the mock");

You'll need these static imports from the Mockito class in order to use the verify method and these verification modes:

import static org.mockito.Mockito.atLeast;
import static org.mockito.Mockito.atLeastOnce;
import static org.mockito.Mockito.atMost;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.only;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;

So in your case the correct syntax will be:

Mockito.verify(mock, times(4)).send()

This verifies that the method send was called 4 times on the mocked object. It will fail if it was called less or more than 4 times.


If you just want to check, if the method has been called once, then you don't need to pass a VerificationMode. A simple

verify(mock).someMethod("was called once");

would be enough. It internally uses verify(mock, times(1)).someMethod("was called once");.


It is possible to have multiple verification calls on the same mock to achieve a "between" verification. Mockito doesn't support something like this verify(mock, between(4,6)).someMethod("was called between 4 and 6 times");, but we can write

verify(mock, atLeast(4)).someMethod("was called at least four times ...");
verify(mock, atMost(6)).someMethod("... and not more than six times");

instead, to get the same behaviour. The bounds are included, so the test case is green when the method was called 4, 5 or 6 times.

Copy/Paste/Calculate Visible Cells from One Column of a Filtered Table

Here a code that works with windows office 2010. This script will ask you for input filtered range of cells and then the paste range.

Please, both ranges should have the same number of cells.

Sub Copy_Filtered_Cells()

Dim from As Variant
Dim too As Variant
Dim thing As Variant
Dim cell As Range

'Selection.SpecialCells(xlCellTypeVisible).Select

    'Set from = Selection.SpecialCells(xlCellTypeVisible)
    Set temp = Application.InputBox("Copy Range :", Type:=8)
    Set from = temp.SpecialCells(xlCellTypeVisible)
    Set too = Application.InputBox("Select Paste range selected cells ( Visible cells only)", Type:=8)



    For Each cell In from
        cell.Copy
        For Each thing In too
            If thing.EntireRow.RowHeight > 0 Then
                thing.PasteSpecial
                Set too = thing.Offset(1).Resize(too.Rows.Count)
                Exit For
            End If
        Next
    Next


End Sub

Enjoy!

Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled

I solved it by myself.

<dependency>
    <groupId>org.hibernate</groupId>
    <artifactId>hibernate-core</artifactId>
    <version>5.0.7.Final</version>
</dependency>

Javascript format date / time

For the date part:(month is 0-indexed while days are 1-indexed)

var date = new Date('2014-8-20');
console.log((date.getMonth()+1) + '/' + date.getDate() + '/' +  date.getFullYear());

for the time you'll want to create a function to test different situations and convert.

LIKE vs CONTAINS on SQL Server

Having run both queries on a SQL Server 2012 instance, I can confirm the first query was fastest in my case.

The query with the LIKE keyword showed a clustered index scan.

The CONTAINS also had a clustered index scan with additional operators for the full text match and a merge join.

Plan

Creating multiline strings in JavaScript

The equivalent in javascript is:

var text = `
This
Is
A
Multiline
String
`;

Here's the specification. See browser support at the bottom of this page. Here are some examples too.

SSL error : routines:SSL3_GET_SERVER_CERTIFICATE:certificate verify failed

could also happen when your local time is off (e.g. before certificate validation time), this was the case in my error...

How to get index using LINQ?

Here's an implementation of the highest-voted answer that returns -1 when the item is not found:

public static int FindIndex<T>(this IEnumerable<T> items, Func<T, bool> predicate)
{
    var itemsWithIndices = items.Select((item, index) => new { Item = item, Index = index });
    var matchingIndices =
        from itemWithIndex in itemsWithIndices
        where predicate(itemWithIndex.Item)
        select (int?)itemWithIndex.Index;

    return matchingIndices.FirstOrDefault() ?? -1;
}

Gradle Build Android Project "Could not resolve all dependencies" error

If you are running on headless CI and are installing the Android SDK through command line, make sure to include the m2repository packages in the --filter argument:

android update sdk --no-ui --filter platform-tools,build-tools-19.0.1,android-19,extra-android-support,extra-android-m2repository,extra-google-m2repository

Update

As of Android SDK Manager rev. 22.6.4 this does not work anymore. Try this instead:

android list sdk --all

You will get a list of all available SDK packages. Look up the numerical values of the components from the first command above ("Google Repository" and others you might be missing).

Install the packages using their numerical values:

android update sdk --no-ui --all --filter <num>

Update #2 (Sept 2017)

With the "new" Android SDK tools that were released earlier this year, the android command is now deprecated, and similar functionality has been moved to a new tool called sdkmanager:

List installed components:

sdkmanager --list

Update installed components:

sdkmanager --update

Install a new component (e.g. build tools version 26.0.0):

sdkmanager 'build-tools;26.0.0'

What does a question mark represent in SQL queries?

The ? is an unnamed parameter which can be filled in by a program running the query to avoid SQL injection.

Cleanest Way to Invoke Cross-Thread Events

Use the synchronisation context if you want to send a result to the UI thread. I needed to change the thread priority so I changed from using thread pool threads (commented out code) and created a new thread of my own. I was still able to use the synchronisation context to return whether the database cancel succeeded or not.

    #region SyncContextCancel

    private SynchronizationContext _syncContextCancel;

    /// <summary>
    /// Gets the synchronization context used for UI-related operations.
    /// </summary>
    /// <value>The synchronization context.</value>
    protected SynchronizationContext SyncContextCancel
    {
        get { return _syncContextCancel; }
    }

    #endregion //SyncContextCancel

    public void CancelCurrentDbCommand()
    {
        _syncContextCancel = SynchronizationContext.Current;

        //ThreadPool.QueueUserWorkItem(CancelWork, null);

        Thread worker = new Thread(new ThreadStart(CancelWork));
        worker.Priority = ThreadPriority.Highest;
        worker.Start();
    }

    SQLiteConnection _connection;
    private void CancelWork()//object state
    {
        bool success = false;

        try
        {
            if (_connection != null)
            {
                log.Debug("call cancel");
                _connection.Cancel();
                log.Debug("cancel complete");
                _connection.Close();
                log.Debug("close complete");
                success = true;
                log.Debug("long running query cancelled" + DateTime.Now.ToLongTimeString());
            }
        }
        catch (Exception ex)
        {
            log.Error(ex.Message, ex);
        }

        SyncContextCancel.Send(CancelCompleted, new object[] { success });
    }

    public void CancelCompleted(object state)
    {
        object[] args = (object[])state;
        bool success = (bool)args[0];

        if (success)
        {
            log.Debug("long running query cancelled" + DateTime.Now.ToLongTimeString());

        }
    }

Jquery mouseenter() vs mouseover()

The mouseenter event differs from mouseover in the way it handles event bubbling. The mouseenter event, only triggers its handler when the mouse enters the element it is bound to, not a descendant. Refer: https://api.jquery.com/mouseenter/

The mouseleave event differs from mouseout in the way it handles event bubbling. The mouseleave event, only triggers its handler when the mouse leaves the element it is bound to, not a descendant. Refer: https://api.jquery.com/mouseleave/

Standard way to embed version into python package?

I prefer to read the package version from installation environment. This is my src/foo/_version.py:

from pkg_resources import get_distribution                                        
                                                                                  
__version__ = get_distribution('osbc').version

Makesure foo is always already installed, that's why a src/ layer is required to prevent foo imported without installation.

In the setup.py, I use setuptools-scm to generate the version automatically.

Spring not autowiring in unit tests with JUnit

Missing Context file location in configuration can cause this, one approach to solve this:

  • Specifying Context file location in ContextConfiguration

like:

@ContextConfiguration(locations = { "classpath:META-INF/your-spring-context.xml" })

More details

@RunWith( SpringJUnit4ClassRunner.class )
@ContextConfiguration(locations = { "classpath:META-INF/your-spring-context.xml" })
public class UserServiceTest extends AbstractJUnit4SpringContextTests {}

Reference:Thanks to @Xstian

How to right-align and justify-align in Markdown?

If you want to use justify align in Jupyter Notebook use the following syntax:

<p style='text-align: justify;'> Your Text </p>

For right alignment:

<p style='text-align: right;'> Your Text </p>

PHP Warning: Unknown: failed to open stream

Experienced the same error, for me it was caused because on my Mac I have changed the DocumentRoot to my users Sites directory.

To fix it, I ran the recursive command to ensure that the Apache service has read permissions.

sudo chmod -R 755 ~/Sites

Xcode 4 - "Valid signing identity not found" error on provisioning profiles on a new Macintosh install

I just run into the similar issue today. Unfortunately my HD died on me so I couldn't do the migration mentioned here in the accepted answer. I had to do the following steps:

  1. Connect to the Apple Developer member center then the iOS provisional portal.
  2. Revoke my certificate.
  3. Create a new certificate by providing a new pair of private and public key.
  4. Remove all the previous provisioning profiles and create new ones.
  5. Download the new provisioning profiles and install them in Xcode by just dragging them to the Xcode icon in the dock.

The same action is also mentioned on this post.

Jquery click not working with ipad

I know this was asked a long time ago but I found an answer while searching for this exact question.

There are two solutions.

You can either set an empty onlick attribute on the html element:

<div class="clickElement" onclick=""></div>

Or you can add it in css by setting the pointer cursor:

.clickElement { cursor:pointer }

The problem is that on ipad, the first click on a non-anchor element registers as a hover. This is not really a bug, because it helps with sites that have hover-menus that haven't been tablet/mobile optimised. Setting the cursor or adding an empty onclick attribute tells the browser that the element is indeed a clickable area.

(via http://www.mitch-solutions.com/blog/17-ipad-jquery-live-click-events-not-working)

How do I calculate the normal vector of a line segment?

Another way to think of it is to calculate the unit vector for a given direction and then apply a 90 degree counterclockwise rotation to get the normal vector.

The matrix representation of the general 2D transformation looks like this:

x' = x cos(t) - y sin(t)
y' = x sin(t) + y cos(t)

where (x,y) are the components of the original vector and (x', y') are the transformed components.

If t = 90 degrees, then cos(90) = 0 and sin(90) = 1. Substituting and multiplying it out gives:

x' = -y
y' = +x

Same result as given earlier, but with a little more explanation as to where it comes from.

Remove all items from RecyclerView

This is how I cleared my recyclerview and added new items to it with animation:

mList.clear();
mAdapter.notifyDataSetChanged();

mSwipeRefreshLayout.setRefreshing(false);

//reset adapter with empty array list (it did the trick animation)
mAdapter = new MyAdapter(context, mList);
recyclerView.setAdapter(mAdapter);

mList.addAll(newList);
mAdapter.notifyDataSetChanged();

Regular expression to match exact number of characters?

Your solution is correct, but there is some redundancy in your regex.
The similar result can also be obtained from the following regex:

^([A-Z]{3})$

The {3} indicates that the [A-Z] must appear exactly 3 times.

How to copy a java.util.List into another java.util.List

I was having the same problem ConcurrentAccessException and mysolution was to:

List<SomeBean> tempList = new ArrayList<>();

for (CartItem item : prodList) {
  tempList.add(item);
}
prodList.clear();
prodList = new ArrayList<>(tempList);

So it works only one operation at the time and avoids the Exeption...

Greater than and less than in one statement

If this is really bothering you, why not write your own method isBetween(orderBean.getFiles().size(),0,5)?

Another option is to use isEmpty as it is a tad clearer:

if(!orderBean.getFiles().isEmpty() && orderBean.getFiles().size() < 5)

Could not connect to SMTP host: localhost, port: 25; nested exception is: java.net.ConnectException: Connection refused: connect

The mail server on CentOS 6 and other IPv6 capable server platforms may be bound to IPv6 localhost (::1) instead of IPv4 localhost (127.0.0.1).

Typical symptoms:

[root@host /]# telnet 127.0.0.1 25
Trying 127.0.0.1...
telnet: connect to address 127.0.0.1: Connection refused

[root@host /]# telnet localhost 25
Trying ::1...
Connected to localhost.
Escape character is '^]'.
220 host ESMTP Exim 4.72 Wed, 14 Aug 2013 17:02:52 +0100

[root@host /]# netstat -plant | grep 25
tcp        0      0 :::25                       :::*                        LISTEN      1082/exim           

If this happens, make sure that you don't have two entries for localhost in /etc/hosts with different IP addresses, like this (bad) example:

[root@host /]# cat /etc/hosts
127.0.0.1 localhost.localdomain localhost localhost4.localdomain4 localhost4
::1       localhost localhost.localdomain localhost6 localhost6.localdomain6

To avoid confusion, make sure you only have one entry for localhost, preferably an IPv4 address, like this:

[root@host /]# cat /etc/hosts
127.0.0.1 localhost  localhost.localdomain   localhost4.localdomain4 localhost4
::1       localhost6 localhost6.localdomain6

HTTP post XML data in C#

In General:

An example of an easy way to post XML data and get the response (as a string) would be the following function:

public string postXMLData(string destinationUrl, string requestXml)
{
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(destinationUrl);
    byte[] bytes;
    bytes = System.Text.Encoding.ASCII.GetBytes(requestXml);
    request.ContentType = "text/xml; encoding='utf-8'";
    request.ContentLength = bytes.Length;
    request.Method = "POST";
    Stream requestStream = request.GetRequestStream();
    requestStream.Write(bytes, 0, bytes.Length);
    requestStream.Close();
    HttpWebResponse response;
    response = (HttpWebResponse)request.GetResponse();
    if (response.StatusCode == HttpStatusCode.OK)
    {
        Stream responseStream = response.GetResponseStream();
        string responseStr = new StreamReader(responseStream).ReadToEnd();
        return responseStr;
    }
    return null;
}

In your specific situation:

Instead of:

request.ContentType = "application/x-www-form-urlencoded";

use:

request.ContentType = "text/xml; encoding='utf-8'";

Also, remove:

string postData = "XMLData=" + Sendingxml;

And replace:

byte[] byteArray = Encoding.UTF8.GetBytes(postData);

with:

byte[] byteArray = Encoding.UTF8.GetBytes(Sendingxml.ToString());

Replace characters from a column of a data frame R

You can use the stringr library:

library('stringr')

a <- runif(10)
b <- letters[1:10]
c <- c(rep('A-B', 4), rep('A_B', 6))
data <- data.frame(a, b, c)

data

#             a b   c
# 1  0.19426707 a A-B
# 2  0.12902673 b A-B
# 3  0.78324955 c A-B
# 4  0.06469028 d A-B
# 5  0.34752264 e A_C
# 6  0.55313288 f A_C
# 7  0.31264280 g A_C
# 8  0.33759921 h A_C
# 9  0.72322599 i A_C
# 10 0.25223075 j A_C

data$c <- str_replace_all(data$c, '_', '-')

data

#             a b   c
# 1  0.19426707 a A-B
# 2  0.12902673 b A-B
# 3  0.78324955 c A-B
# 4  0.06469028 d A-B
# 5  0.34752264 e A-C
# 6  0.55313288 f A-C
# 7  0.31264280 g A-C
# 8  0.33759921 h A-C
# 9  0.72322599 i A-C
# 10 0.25223075 j A-C

Note that this does change factored variables into character.

Determine Whether Two Date Ranges Overlap

enter image description here

Here is the code that does the magic:

 var isOverlapping =  ((A == null || D == null || A <= D) 
            && (C == null || B == null || C <= B)
            && (A == null || B == null || A <= B)
            && (C == null || D == null || C <= D));

Where..

  • A -> 1Start
  • B -> 1End
  • C -> 2Start
  • D -> 2End

Proof? Check out this test console code gist.

LINQ with groupby and count

Assuming userInfoList is a List<UserInfo>:

        var groups = userInfoList
            .GroupBy(n => n.metric)
            .Select(n => new
            {
                MetricName = n.Key,
                MetricCount = n.Count()
            }
            )
            .OrderBy(n => n.MetricName);

The lambda function for GroupBy(), n => n.metric means that it will get field metric from every UserInfo object encountered. The type of n is depending on the context, in the first occurrence it's of type UserInfo, because the list contains UserInfo objects. In the second occurrence n is of type Grouping, because now it's a list of Grouping objects.

Groupings have extension methods like .Count(), .Key() and pretty much anything else you would expect. Just as you would check .Lenght on a string, you can check .Count() on a group.

Disable hover effects on mobile browsers

In my project we solved this issue using https://www.npmjs.com/package/postcss-hover-prefix and https://modernizr.com/ First we post-process output css files with postcss-hover-prefix. It adds .no-touch for all css hover rules.

const fs = require("fs");
const postcss = require("postcss");
const hoverPrfx = require("postcss-hover-prefix");

var css = fs.readFileSync(cssFileName, "utf8").toString();
postcss()
   .use(hoverPrfx("no-touch"))
   .process(css)
   .then((result) => {
      fs.writeFileSync(cssFileName, result);
   });

css

a.text-primary:hover {
  color: #62686d;
}

becomes

.no-touch a.text-primary:hover {
  color: #62686d;
}

At runtime Modernizr automatically adds css classes to html tag like this

<html class="wpfe-full-height js flexbox flexboxlegacy canvas canvastext webgl 
  no-touch 
  geolocation postmessage websqldatabase indexeddb hashchange
  history draganddrop websockets rgba hsla multiplebgs backgroundsize borderimage
  borderradius boxshadow textshadow opacity cssanimations csscolumns cssgradients
  cssreflections csstransforms csstransforms3d csstransitions fontface
  generatedcontent video audio localstorage sessionstorage webworkers
  applicationcache svg inlinesvg smil svgclippaths websocketsbinary">

Such post-processing of css plus Modernizr disables hover for touch devices and enables for others. In fact this approach was inspired by Bootstrap 4, how they solve the same issue: https://v4-alpha.getbootstrap.com/getting-started/browsers-devices/#sticky-hoverfocus-on-mobile

Reading e-mails from Outlook with Python through MAPI

Sorry for my bad English. Checking Mails using Python with MAPI is easier,

outlook =win32com.client.Dispatch("Outlook.Application").GetNamespace("MAPI")
folder = outlook.Folders[5]
Subfldr = folder.Folders[5]
messages_REACH = Subfldr.Items
message = messages_REACH.GetFirst()

Here we can get the most first mail into the Mail box, or into any sub folder. Actually, we need to check the Mailbox number & orientation. With the help of this analysis we can check each mailbox & its sub mailbox folders.

Similarly please find the below code, where we can see, the last/ earlier mails. How we need to check.

`outlook =win32com.client.Dispatch("Outlook.Application").GetNamespace("MAPI")
folder = outlook.Folders[5]
Subfldr = folder.Folders[5]
messages_REACH = Subfldr.Items
message = messages_REACH.GetLast()`

With this we can get most recent email into the mailbox. According to the above mentioned code, we can check our all mail boxes, & its sub folders.

Formatting MM/DD/YYYY dates in textbox in VBA

While I agree with what's mentioned in the answers below, suggesting that this is a very bad design for a Userform unless copious amounts of error checks are included...

to accomplish what you need to do, with minimal changes to your code, there are two approaches.

  1. Use KeyUp() event instead of Change event for the textbox. Here is an example:

    Private Sub TextBox2_KeyUp(ByVal KeyCode As MSForms.ReturnInteger, ByVal Shift As Integer)
    
        Dim TextStr As String
        TextStr = TextBox2.Text
    
        If KeyCode <> 8 Then ' i.e. not a backspace
    
            If (Len(TextStr) = 2 Or Len(TextStr) = 5) Then
                TextStr = TextStr & "/"
            End If
    
        End If
        TextBox2.Text = TextStr
    End Sub
    
  2. Alternately, if you need to use the Change() event, use the following code. This alters the behavior so the user keeps entering the numbers, as

    12072003
    

while the result as he's typing appears as

    12/07/2003

But the '/' character appears only once the first character of the DD i.e. 0 of 07 is entered. Not ideal, but will still handle backspaces.

    Private Sub TextBox1_Change()
        Dim TextStr As String

        TextStr = TextBox1.Text

        If (Len(TextStr) = 3 And Mid(TextStr, 3, 1) <> "/") Then
            TextStr = Left(TextStr, 2) & "/" & Right(TextStr, 1)
        ElseIf (Len(TextStr) = 6 And Mid(TextStr, 6, 1) <> "/") Then
            TextStr = Left(TextStr, 5) & "/" & Right(TextStr, 1)
        End If

        TextBox1.Text = TextStr
    End Sub

ASP.NET: Session.SessionID changes between requests

my problem was that we had this set in web.config

<httpCookies httpOnlyCookies="true" requireSSL="true" />

this means that when debugging in non-SSL (the default), the auth cookie would not get sent back to the server. this would mean that the server would send a new auth cookie (with a new session) for every request back to the client.

the fix is to either set requiressl to false in web.config and true in web.release.config or turn on SSL while debugging:

turn on SSL

How to loop through files matching wildcard in batch file

Assuming you have two programs that process the two files, process_in.exe and process_out.exe:

for %%f in (*.in) do (
    echo %%~nf
    process_in "%%~nf.in"
    process_out "%%~nf.out"
)

%%~nf is a substitution modifier, that expands %f to a file name only. See other modifiers in https://technet.microsoft.com/en-us/library/bb490909.aspx (midway down the page) or just in the next answer.

Bash command to sum a column of numbers

You can use bc (calculator). Assuming your file with #s is called "n":

$ cat n
1
2
3
$ (cat n | tr "\012" "+" ; echo "0") | bc 
6

The tr changes all newlines to "+"; then we append 0 after the last plus, then we pipe the expression (1+2+3+0) to the calculator

Or, if you are OK with using awk or perl, here's a Perl one-liner:

$perl -nle '$sum += $_ } END { print $sum' n
6

Class name does not name a type in C++

error 'Class' does not name a type

Just in case someone does the same idiotic thing I did ... I was creating a small test program from scratch and I typed Class instead of class (with a small C). I didn't take any notice of the quotes in the error message and spent a little too long not understanding my problem.

My search for a solution brought me here so I guess the same could happen to someone else.

Could not load file or assembly "System.Net.Http, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a"

You can fix this by upgrading your project to .NET Framework 4.7.2. This was answered by Alex Ghiondea - MSFT. Please go upvote him as he truly deserves it!

This is documented as a known issue in .NET Framework 4.7.1.

As a workaround you can add these targets to your project. They will remove the DesignFacadesToFilter from the list of references passed to SGEN (and add them back once SGEN is done)

<Target Name="RemoveDesignTimeFacadesBeforeSGen" BeforeTargets="GenerateSerializationAssemblies">
  <ItemGroup>
    <DesignFacadesToFilter Include="System.IO.Compression.ZipFile" />
    <_FilterOutFromReferencePath Include="@(_DesignTimeFacadeAssemblies_Names->'%(OriginalIdentity)')" 
        Condition="'@(DesignFacadesToFilter)' == '@(_DesignTimeFacadeAssemblies_Names)' and '%(Identity)' != ''" /> 
    <ReferencePath Remove="@(_FilterOutFromReferencePath)" />
  </ItemGroup>
  <Message Importance="normal" Text="Removing DesignTimeFacades from ReferencePath before running SGen." /> </Target>

<Target Name="ReAddDesignTimeFacadesBeforeSGen" AfterTargets="GenerateSerializationAssemblies">
  <ItemGroup>
    <ReferencePath Include="@(_FilterOutFromReferencePath)" />
  </ItemGroup>
  <Message Importance="normal" Text="Adding back DesignTimeFacades from ReferencePath now that SGen has ran." />
</Target>

Another option (machine wide) is to add the following binding redirect to sgen.exe.config:

<runtime>
  <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
    <dependentAssembly>
      <assemblyIdentity name="System.IO.Compression.ZipFile" publicKeyToken="b77a5c561934e089" culture="neutral" />
      <bindingRedirect oldVersion="0.0.0.0-4.2.0.0" newVersion="4.0.0.0" />
    </dependentAssembly>
  </assemblyBinding>
</runtime> This will only work on machines with .NET Framework 4.7.1. installed. Once .NET Framework 4.7.2 is installed on that machine, this workaround should be removed.

private constructor

It's common when you want to implement a singleton. The class can have a static "factory method" that checks if the class has already been instantiated, and calls the constructor if it hasn't.

Save results to csv file with Python

This is how I do it

 import csv
    file = open('???.csv', 'r')
    read = csv.reader(file)
    for column in read:
            file = open('???.csv', 'r')
            read = csv.reader(file)
            file.close()
            file = open('????.csv', 'a', newline='')
            write = csv.writer(file, delimiter = ",")
            write.writerow((, ))
            file.close()

Loop through all nested dictionary values?

There are potential problems if you write your own recursive implementation or the iterative equivalent with stack. See this example:

    dic = {}
    dic["key1"] = {}
    dic["key1"]["key1.1"] = "value1"
    dic["key2"]  = {}
    dic["key2"]["key2.1"] = "value2"
    dic["key2"]["key2.2"] = dic["key1"]
    dic["key2"]["key2.3"] = dic

In the normal sense, nested dictionary will be a n-nary tree like data structure. But the definition doesn't exclude the possibility of a cross edge or even a back edge (thus no longer a tree). For instance, here key2.2 holds to the dictionary from key1, key2.3 points to the entire dictionary(back edge/cycle). When there is a back edge(cycle), the stack/recursion will run infinitely.

                          root<-------back edge
                        /      \           |
                     _key1   __key2__      |
                    /       /   \    \     |
               |->key1.1 key2.1 key2.2 key2.3
               |   /       |      |
               | value1  value2   |
               |                  | 
              cross edge----------|

If you print this dictionary with this implementation from Scharron

    def myprint(d):
      for k, v in d.items():
        if isinstance(v, dict):
          myprint(v)
        else:
          print "{0} : {1}".format(k, v)

You would see this error:

    RuntimeError: maximum recursion depth exceeded while calling a Python object

The same goes with the implementation from senderle.

Similarly, you get an infinite loop with this implementation from Fred Foo:

    def myprint(d):
        stack = list(d.items())
        while stack:
            k, v = stack.pop()
            if isinstance(v, dict):
                stack.extend(v.items())
            else:
                print("%s: %s" % (k, v))

However, Python actually detects cycles in nested dictionary:

    print dic
    {'key2': {'key2.1': 'value2', 'key2.3': {...}, 
       'key2.2': {'key1.1': 'value1'}}, 'key1': {'key1.1': 'value1'}}

"{...}" is where a cycle is detected.

As requested by Moondra this is a way to avoid cycles (DFS):

def myprint(d): 
    stack = list(d.items()) 
    visited = set() 
    while stack: 
        k, v = stack.pop() 
        if isinstance(v, dict): 
            if k not in visited: 
                stack.extend(v.items()) 
        else: 
            print("%s: %s" % (k, v)) 
        visited.add(k)

Name does not exist in the current context

I solved mine by using an Import directive under my Page directive. You may also want to add the namespace to your Inherits attribute of your Page directive.

Since it appears that your default namespace is "stman.Members", try: <%@ Page Title="" Language="C#" MasterPageFile="~/Members/Members.master" AutoEventWireup="true" CodeFile="Jobs.aspx.cs" Inherits="stman.Members.Members_Jobs" %> <%@ Import Namespace="stman.Members"%>

Additionally, data that I wanted to pass between aspx.cs and aspx, I put inside a static class inside the namespace. That static class was available to move data around in the name space and no longer has a "not in context" error.

Difference between Destroy and Delete

Yes there is a major difference between the two methods Use delete_all if you want records to be deleted quickly without model callbacks being called

If you care about your models callbacks then use destroy_all

From the official docs

http://apidock.com/rails/ActiveRecord/Base/destroy_all/class

destroy_all(conditions = nil) public

Destroys the records matching conditions by instantiating each record and calling its destroy method. Each object’s callbacks are executed (including :dependent association options and before_destroy/after_destroy Observer methods). Returns the collection of objects that were destroyed; each will be frozen, to reflect that no changes should be made (since they can’t be persisted).

Note: Instantiation, callback execution, and deletion of each record can be time consuming when you’re removing many records at once. It generates at least one SQL DELETE query per record (or possibly more, to enforce your callbacks). If you want to delete many rows quickly, without concern for their associations or callbacks, use delete_all instead.

How to exclude records with certain values in sql select

One way:

SELECT DISTINCT sc.StoreId
FROM StoreClients sc
WHERE NOT EXISTS(
    SELECT * FROM StoreClients sc2 
    WHERE sc2.StoreId = sc.StoreId AND sc2.ClientId = 5)

How to call getClass() from a static method in Java?

getClass() method is defined in Object class with the following signature:

public final Class getClass()

Since it is not defined as static, you can not call it within a static code block. See these answers for more information: Q1, Q2, Q3.

If you're in a static context, then you have to use the class literal expression to get the Class, so you basically have to do like:

Foo.class

This type of expression is called Class Literals and they are explained in Java Language Specification Book as follows:

A class literal is an expression consisting of the name of a class, interface, array, or primitive type followed by a `.' and the token class. The type of a class literal is Class. It evaluates to the Class object for the named type (or for void) as defined by the defining class loader of the class of the current instance.

You can also find information about this subject on API documentation for Class.

Regular expression to validate US phone numbers?

The easiest way to match both

^\([0-9]{3}\)[0-9]{3}-[0-9]{4}$

and

^[0-9]{3}-[0-9]{3}-[0-9]{4}$

is to use alternation ((...|...)): specify them as two mostly-separate options:

^(\([0-9]{3}\)|[0-9]{3}-)[0-9]{3}-[0-9]{4}$

By the way, when Americans put the area code in parentheses, we actually put a space after that; for example, I'd write (123) 123-1234, not (123)123-1234. So you might want to write:

^(\([0-9]{3}\) |[0-9]{3}-)[0-9]{3}-[0-9]{4}$

(Though it's probably best to explicitly demonstrate the format that you expect phone numbers to be in.)

Change Background color (css property) using Jquery

Change Background Color using on click button jquery

Below is the code of jquery, which you can put in your head tag.

jQuery Code:

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
<script>
    $(document).ready(function(){
      $("button").click(function(){
        $("div").addClass("myclass");
      });
    });
</script>

CSS Code:

<style>
    .myclass {
        background-color: red;
        padding: 100px;
        color: #fff;
    }
</style>

HTML Code:

<body>
    <div>Lorem Ipsum is simply dummy text of the printing and typesetting industry.</div>
    <button>Click Here</button>
</body>

How to put two divs on the same line with CSS in simple_form in rails?

You can't float or set the width of an inline element. Remove display: inline; from both classes and your markup should present fine.

EDIT: You can set the width, but it will cause the element to be rendered as a block.

Select row on click react-table

There is a HOC included for React-Table that allows for selection, even when filtering and paginating the table, the setup is slightly more advanced than the basic table so read through the info in the link below first.


enter image description here



After importing the HOC you can then use it like this with the necessary methods:

/**
* Toggle a single checkbox for select table
*/
toggleSelection(key: number, shift: string, row: string) {
    // start off with the existing state
    let selection = [...this.state.selection];
    const keyIndex = selection.indexOf(key);

    // check to see if the key exists
    if (keyIndex >= 0) {
        // it does exist so we will remove it using destructing
        selection = [
            ...selection.slice(0, keyIndex),
            ...selection.slice(keyIndex + 1)
        ];
    } else {
        // it does not exist so add it
        selection.push(key);
    }
    // update the state
    this.setState({ selection });
}

/**
* Toggle all checkboxes for select table
*/
toggleAll() {
    const selectAll = !this.state.selectAll;
    const selection = [];

    if (selectAll) {
        // we need to get at the internals of ReactTable
        const wrappedInstance = this.checkboxTable.getWrappedInstance();
        // the 'sortedData' property contains the currently accessible records based on the filter and sort
        const currentRecords = wrappedInstance.getResolvedState().sortedData;
        // we just push all the IDs onto the selection array
        currentRecords.forEach(item => {
            selection.push(item._original._id);
        });
    }
    this.setState({ selectAll, selection });
}

/**
* Whether or not a row is selected for select table
*/
isSelected(key: number) {
    return this.state.selection.includes(key);
}

<CheckboxTable
    ref={r => (this.checkboxTable = r)}
    toggleSelection={this.toggleSelection}
    selectAll={this.state.selectAll}
    toggleAll={this.toggleAll}
    selectType="checkbox"
    isSelected={this.isSelected}
    data={data}
    columns={columns}
/>

See here for more information:
https://github.com/tannerlinsley/react-table/tree/v6#selecttable

Here is a working example:
https://codesandbox.io/s/react-table-select-j9jvw

How can a query multiply 2 cell for each row MySQL?

I'm assuming this should work. This will actually put it in the column in your database

UPDATE yourTable yt SET yt.Total = (yt.Pieces * yt.Price)

If you want to retrieve the 2 values from the database and put your multiplication in the third column of the result only, then

SELECT yt.Pieces, yt.Price, (yt.Pieces * yt.Price) as 'Total' FROM yourTable yt

will be your friend

Eclipse compilation error: The hierarchy of the type 'Class name' is inconsistent

I had the same exact problem marker and solved it by removing the @Override annotation from a method that was in fact the first implementation (the "super" one being an abstract method) and not an override.

How to capitalize the first character of each word in a string

Since nobody used regexp's let's do it with regexp's. This solution is for fun. :) (update: actually I just discovered that there is an answer with regexps, anyway I would like to leave this answer in place since it is better looking :) ):

public class Capitol 
{
    public static String now(String str)
    {
        StringBuffer b = new StringBuffer();
        Pattern p = Pattern.compile("\\b(\\w){1}");
        Matcher m = p.matcher(str);
        while (m.find())
        {
            String s = m.group(1);
            m.appendReplacement(b, s.toUpperCase());
        }
        m.appendTail(b);
        return b.toString();
    }
}

Usage

Capitol.now("ab cd"));
Capitol.now("winnie the Pooh"));
Capitol.now("please talk loudly!"));
Capitol.now("miles o'Brien"));

Does Python SciPy need BLAS?

On Fedora, this works:

 yum install lapack lapack-devel blas blas-devel
 pip install numpy
 pip install scipy

Remember to install 'lapack-devel' and 'blas-devel' in addition to 'blas' and 'lapack' otherwise you'll get the error you mentioned or the "numpy.distutils.system_info.LapackNotFoundError" error.

Property getters and setters

Try using this:

var x:Int!

var xTimesTwo:Int {
    get {
        return x * 2
    }
    set {
        x = newValue / 2
    }
}

This is basically Jack Wu's answer, but the difference is that in Jack Wu's answer his x variable is var x: Int, in mine, my x variable is like this: var x: Int!, so all I did was make it an optional type.

AngularJS: Uncaught Error: [$injector:modulerr] Failed to instantiate module?

Try using No Wrap - In Head or No wrap - in body in your fiddle:

Working fiddle: http://jsfiddle.net/Q5hd6/

Explanation:

Angular begins compiling the DOM when the DOM is fully loaded. You register your code to run onLoad (onload option in fiddle) => it's too late to register your myApp module because angular begins compiling the DOM and angular sees that there is no module named myApp and throws an exception.

By using No Wrap - In Head, your code looks like this:

<head>

    <script type='text/javascript' src='//cdnjs.cloudflare.com/ajax/libs/angular.js/1.2.1/angular.js'></script>

    <script type='text/javascript'>
      //Your script.
    </script>

</head>

Your script has a chance to run before angular begins compiling the DOM and myApp module is already created when angular starts compiling the DOM.

List of IP addresses/hostnames from local network in Python

I have done following code to get the IP of MAC known device. This can be modified accordingly to obtain all IPs with some string manipulation. Hope this will help you.

#running windows cmd line  statement and put output into a string
cmd_out = os.popen("arp -a").read()
line_arr = cmd_out.split('\n')
line_count = len(line_arr)


#search in all lines for ip
for i in range(0, line_count):
    y = line_arr[i]
    z = y.find(mac_address)

    #if mac address is found then get the ip using regex matching
    if z > 0:
        ip_out= re.search('[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+', y, re.M | re.I)

How to ensure that there is a delay before a service is started in systemd?

You can create a .timer systemd unit file to control the execution of your .service unit file.

So for example, to wait for 1 minute after boot-up before starting your foo.service, create a foo.timer file in the same directory with the contents:

[Timer]
OnBootSec=1min

It is important that the service is disabled (so it doesn't start at boot), and the timer enabled, for all this to work (thanks to user tride for this):

systemctl disable foo.service
systemctl enable foo.timer

You can find quite a few more options and all information needed here: https://wiki.archlinux.org/index.php/Systemd/Timers

How to run a JAR file

java -classpath Predit.jar your.package.name.MainClass

Finding modified date of a file/folder

You can try dirTimesJS.bat and fileTimesJS.bat

example:

C:\>dirTimesJS.bat %windir%

directory timestamps for C:\Windows :

Modified : 2020-11-22 22:12:55
Modified - milliseconds passed : 1604607175000
Modified day of the week : 4

Created : 2019-12-11 11:03:44
Created - milliseconds passed : 1575709424000
Created day of the week : 6

Accessed : 2020-11-16 16:39:22
Accessed - milliseconds passed : 1605019162000
Accessed day of the week : 2

C:\>fileTimesJS.bat %windir%\notepad.exe

file timestamps for C:\Windows\notepad.exe :

Modified : 2020-09-08 08:33:31
Modified - milliseconds passed : 1599629611000
Modified day of the week : 3

Created : 2020-09-08 08:33:31
Created - milliseconds passed : 1599629611000
Created day of the week : 3

Accessed : 2020-11-23 23:59:22
Accessed - milliseconds passed : 1604613562000
Accessed day of the week : 4

Displaying splash screen for longer than default seconds

The simplest way to achieve this is to creat an UIImageView with "Default.png" on the top of your first ViewController's UIView.

And add an Timer to remove the UIImageView after seconds you expected.

What is getattr() exactly and how do I use it?

setattr()

We use setattr to add an attribute to our class instance. We pass the class instance, the attribute name, and the value.

getattr()

With getattr we retrive these values

For example

Employee = type("Employee", (object,), dict())

employee = Employee()

# Set salary to 1000
setattr(employee,"salary", 1000 )

# Get the Salary
value = getattr(employee, "salary")

print(value)

Qt: resizing a QLabel containing a QPixmap while keeping its aspect ratio

I tried using phyatt's AspectRatioPixmapLabel class, but experienced a few problems:

  • Sometimes my app entered an infinite loop of resize events. I traced this back to the call of QLabel::setPixmap(...) inside the resizeEvent method, because QLabel actually calls updateGeometry inside setPixmap, which may trigger resize events...
  • heightForWidth seemed to be ignored by the containing widget (a QScrollArea in my case) until I started setting a size policy for the label, explicitly calling policy.setHeightForWidth(true)
  • I want the label to never grow more than the original pixmap size
  • QLabel's implementation of minimumSizeHint() does some magic for labels containing text, but always resets the size policy to the default one, so I had to overwrite it

That said, here is my solution. I found that I could just use setScaledContents(true) and let QLabel handle the resizing. Of course, this depends on the containing widget / layout honoring the heightForWidth.

aspectratiopixmaplabel.h

#ifndef ASPECTRATIOPIXMAPLABEL_H
#define ASPECTRATIOPIXMAPLABEL_H

#include <QLabel>
#include <QPixmap>

class AspectRatioPixmapLabel : public QLabel
{
    Q_OBJECT
public:
    explicit AspectRatioPixmapLabel(const QPixmap &pixmap, QWidget *parent = 0);
    virtual int heightForWidth(int width) const;
    virtual bool hasHeightForWidth() { return true; }
    virtual QSize sizeHint() const { return pixmap()->size(); }
    virtual QSize minimumSizeHint() const { return QSize(0, 0); }
};

#endif // ASPECTRATIOPIXMAPLABEL_H

aspectratiopixmaplabel.cpp

#include "aspectratiopixmaplabel.h"

AspectRatioPixmapLabel::AspectRatioPixmapLabel(const QPixmap &pixmap, QWidget *parent) :
    QLabel(parent)
{
    QLabel::setPixmap(pixmap);
    setScaledContents(true);
    QSizePolicy policy(QSizePolicy::Maximum, QSizePolicy::Maximum);
    policy.setHeightForWidth(true);
    this->setSizePolicy(policy);
}

int AspectRatioPixmapLabel::heightForWidth(int width) const
{
    if (width > pixmap()->width()) {
        return pixmap()->height();
    } else {
        return ((qreal)pixmap()->height()*width)/pixmap()->width();
    }
}

Aligning a float:left div to center?

use display:inline-block; instead of float

you can't centre floats, but inline-blocks centre as if they were text, so on the outer overall container of your "row" - you would set text-align: center; then for each image/caption container (it's those which would be inline-block;) you can re-align the text to left if you require

Count the number occurrences of a character in a string

I am a fan of the pandas library, in particular the value_counts() method. You could use it to count the occurrence of each character in your string:

>>> import pandas as pd
>>> phrase = "I love the pandas library and its `value_counts()` method"
>>> pd.Series(list(phrase)).value_counts()
     8
a    5
e    4
t    4
o    3
n    3
s    3
d    3
l    3
u    2
i    2
r    2
v    2
`    2
h    2
p    1
b    1
I    1
m    1
(    1
y    1
_    1
)    1
c    1
dtype: int64

json.net has key method?

Just use x["error_msg"]. If the property doesn't exist, it returns null.

NSAttributedString add text alignment

Swift 4.0+

let titleParagraphStyle = NSMutableParagraphStyle()
titleParagraphStyle.alignment = .center

let titleFont = UIFont.preferredFont(forTextStyle: UIFontTextStyle.headline)
let title = NSMutableAttributedString(string: "You Are Registered", 
    attributes: [.font: titleFont,    
    .foregroundColor: UIColor.red, 
    .paragraphStyle: titleParagraphStyle])

Swift 3.0+

let titleParagraphStyle = NSMutableParagraphStyle()
titleParagraphStyle.alignment = .center

let titleFont = UIFont.preferredFont(forTextStyle: UIFontTextStyle.headline)
let title = NSMutableAttributedString(string: "You Are Registered", 
    attributes: [NSFontAttributeName:titleFont,    
    NSForegroundColorAttributeName:UIColor.red, 
    NSParagraphStyleAttributeName: titleParagraphStyle])

(original answer below)

Swift 2.0+

let titleParagraphStyle = NSMutableParagraphStyle()
titleParagraphStyle.alignment = .Center

let titleFont = UIFont.preferredFontForTextStyle(UIFontTextStyleHeadline)
let title = NSMutableAttributedString(string: "You Are Registered",
    attributes:[NSFontAttributeName:titleFont,   
    NSForegroundColorAttributeName:UIColor.redColor(), 
    NSParagraphStyleAttributeName: titleParagraphStyle])

Order a List (C#) by many fields?

Your object should implement the IComparable interface.

With it your class becomes a new function called CompareTo(T other). Within this function you can make any comparison between the current and the other object and return an integer value about if the first is greater, smaller or equal to the second one.

How set background drawable programmatically in Android

Use butterknife to bind the drawable resource to a variable by adding this to the top of your class (before any methods).

@Bind(R.id.some_layout)
RelativeLayout layout;
@BindDrawable(R.drawable.some_drawable)
Drawable background;

then inside one of your methods add

layout.setBackground(background);

That's all you need

Get generic type of java.util.List

You can do the same for method parameters as well:

Method method = someClass.getDeclaredMethod("someMethod");
Type[] types = method.getGenericParameterTypes();
//Now assuming that the first parameter to the method is of type List<Integer>
ParameterizedType pType = (ParameterizedType) types[0];
Class<?> clazz = (Class<?>) pType.getActualTypeArguments()[0];
System.out.println(clazz); //prints out java.lang.Integer

How can I center text (horizontally and vertically) inside a div block?

Adjusting line height to get the vertical alignment.

line-height: 90px;

How to pass parameters to ThreadStart method in Thread?

According to your question...

How to pass parameters to Thread.ThreadStart() method in C#?

...and the error you encountered, you would have to correct your code from

Thread thread = new Thread(new ThreadStart(download(filename));

to

Thread thread = new Thread(new ThreadStart(download));
thread.Start(filename);



However, the question is more complex as it seems at first.

The Thread class currently (4.7.2) provides several constructors and a Start method with overloads.

These relevant constructors for this question are:

public Thread(ThreadStart start);

and

public Thread(ParameterizedThreadStart start);

which either take a ThreadStart delegate or a ParameterizedThreadStart delegate.

The corresponding delegates look like this:

public delegate void ThreadStart();
public delegate void ParameterizedThreadStart(object obj);

So as can be seen, the correct constructor to use seems to be the one taking a ParameterizedThreadStart delegate so that some method conform to the specified signature of the delegate can be started by the thread.

A simple example for instanciating the Thread class would be

Thread thread = new Thread(new ParameterizedThreadStart(Work));

or just

Thread thread = new Thread(Work);

The signature of the corresponding method (called Work in this example) looks like this:

private void Work(object data)
{
   ...
}

What is left is to start the thread. This is done by using either

public void Start();

or

public void Start(object parameter);

While Start() would start the thread and pass null as data to the method, Start(...) can be used to pass anything into the Work method of the thread.

There is however one big problem with this approach: Everything passed into the Work method is cast into an object. That means within the Work method it has to be cast to the original type again like in the following example:

public static void Main(string[] args)
{
    Thread thread = new Thread(Work);

    thread.Start("I've got some text");
    Console.ReadLine();
}

private static void Work(object data)
{
    string message = (string)data; // Wow, this is ugly

    Console.WriteLine($"I, the thread write: {message}");
}



Casting is something you typically do not want to do.

What if someone passes something else which is not a string? As this seems not possible at first (because It is my method, I know what I do or The method is private, how should someone ever be able to pass anything to it?) you may possibly end up with exactly that case for various reasons. As some cases may not be a problem, others are. In such cases you will probably end up with an InvalidCastException which you probably will not notice because it simply terminates the thread.

As a solution you would expect to get a generic ParameterizedThreadStart delegate like ParameterizedThreadStart<T> where T would be the type of data you want to pass into the Work method. Unfortunately something like this does not exist (yet?).

There is however a suggested solution to this issue. It involves creating a class which contains both, the data to be passed to the thread as well as the method that represents the worker method like this:

public class ThreadWithState
{
    private string message;

    public ThreadWithState(string message)
    {
        this.message = message;
    }

    public void Work()
    {
        Console.WriteLine($"I, the thread write: {this.message}");
    }
}

With this approach you would start the thread like this:

ThreadWithState tws = new ThreadWithState("I've got some text");
Thread thread = new Thread(tws.Work);

thread.Start();

So in this way you simply avoid casting around and have a typesafe way of providing data to a thread ;-)

AWS - Disconnected : No supported authentication methods available (server sent :publickey)

While trying to connect to a SiteGround server via Putty I had the same problem. Their instructions are pretty thorough, and must work for some people, but didn't work for me.

They recommend running pageant.exe, which runs in the background. You register your key(s) with Pageant, and it's supposed to let Putty know about the keys when it tries to connect.

In a couple of places I found suggestions to specify the key directly in the Putty session definition: Putty Configuration > Connection > SSH > Auth > "Private key file for authentication", then browse to your key file in .ppk format.

Doing this without running Pageant resolved the problem for me.

How can I revert a single file to a previous version?

You can take a diff that undoes the changes you want and commit that.

E.g. If you want to undo the changes in the range from..to, do the following

git diff to..from > foo.diff  # get a reverse diff
patch < foo.diff
git commit -a -m "Undid changes from..to".

Bitwise and in place of modulus operator

First of all, it's actually not accurate to say that

x % 2 == x & 1

Simple counterexample: x = -1. In many languages, including Java, -1 % 2 == -1. That is, % is not necessarily the traditional mathematical definition of modulo. Java calls it the "remainder operator", for example.

With regards to bitwise optimization, only modulo powers of two can "easily" be done in bitwise arithmetics. Generally speaking, only modulo powers of base b can "easily" be done with base b representation of numbers.

In base 10, for example, for non-negative N, N mod 10^k is just taking the least significant k digits.

References

Colorized grep -- viewing the entire file with highlighted matches

Is there some way I can tell grep to print every line being read regardless of whether there's a match?

Option -C999 will do the trick in the absence of an option to display all context lines. Most other grep variants support this too. However: 1) no output is produced when no match is found and 2) this option has a negative impact on grep's efficiency: when the -C value is large this many lines may have to be temporarily stored in memory for grep to determine which lines of context to display when a match occurs. Note that grep implementations do not load input files but rather reads a few lines or use a sliding window over the input. The "before part" of the context has to be kept in a window (memory) to output the "before" context lines later when a match is found.

A pattern such as ^|PATTERN or PATTERN|$ or any empty-matching sub-pattern for that matter such as [^ -~]?|PATTERN is a nice trick. However, 1) these patterns don't show non-matching lines highlighted as context and 2) this can't be used in combination with some other grep options, such as -F and -w for example.

So none of these approaches are satisfying to me. I'm using ugrep, and enhanced grep with option -y to efficiently display all non-matching output as color-highlighted context lines. Other grep-like tools such as ag and ripgrep also offer a pass-through option. But ugrep is compatible with GNU/BSD grep and offers a superset of grep options like -y and -Q. For example, here is what option -y shows when combined with -Q (interactive query UI to enter patterns):

ugrep -Q -y FILE ...

Hash string in c#

I don't really understand the full scope of your question, but if all you need is a hash of the string, then it's very easy to get that.

Just use the GetHashCode method.

Like this:

string hash = username.GetHashCode();

200 PORT command successful. Consider using PASV. 425 Failed to establish connection

Try using the passive command before using ls.

From FTP client, to check if the FTP server supports passive mode, after login, type quote PASV.

Following are connection examples to a vsftpd server with passive mode on and off

vsftpd with pasv_enable=NO:

# ftp localhost
Connected to localhost.localdomain.
220 (vsFTPd 2.3.5)
Name (localhost:john): anonymous
331 Please specify the password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> quote PASV
550 Permission denied.
ftp> 

vsftpd with pasv_enable=YES:

# ftp localhost
Connected to localhost.localdomain.
220 (vsFTPd 2.3.5)
Name (localhost:john): anonymous
331 Please specify the password.
Password:
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> quote PASV
227 Entering Passive Mode (127,0,0,1,173,104).
ftp> 

TSQL DATETIME ISO 8601

When dealing with dates in SQL Server, the ISO-8601 format is probably the best way to go, since it just works regardless of your language and culture settings.

In order to INSERT data into a SQL Server table, you don't need any conversion codes or anything at all - just specify your dates as literal strings

INSERT INTO MyTable(DateColumn) VALUES('20090430 12:34:56.790')

and you're done.

If you need to convert a date column to ISO-8601 format on SELECT, you can use conversion code 126 or 127 (with timezone information) to achieve the ISO format.

SELECT CONVERT(VARCHAR(33), DateColumn, 126) FROM MyTable

should give you:

2009-04-30T12:34:56.790

What is the best way to check for Internet connectivity using .NET?

Introduction

In some scenarios you need to check whether internet is available or not using C# code in windows applications. May be to download or upload a file using internet in windows forms or to get some data from database which is at remote location, in these situations internet check is compulsory.

There are some ways to check internet availability using C# from code behind. All such ways are explained here including their limitations.

  1. InternetGetConnectedState(wininet)

The 'wininet' API can be used to check the local system has active internet connection or not. The namespace used for this is 'System.Runtime.InteropServices' and import the dll 'wininet.dll' using DllImport. After this create a boolean variable with extern static with a function name InternetGetConnectedState with two parameters description and reservedValue as shown in example.

Note: The extern modifier is used to declare a method that is implemented externally. A common use of the extern modifier is with the DllImport attribute when you are using Interop services to call into unmanaged code. In this case, the method must also be declared as static.

Next create a method with name 'IsInternetAvailable' as boolean. The above function will be used in this method which returns internet status of local system

[DllImport("wininet.dll")]
private extern static bool InternetGetConnectedState(out int description, int reservedValue);
public static bool IsInternetAvailable()
{
    try
    {
        int description;
        return InternetGetConnectedState(out description, 0);
    }
    catch (Exception ex)
    {
        return false;
    }
}
  1. GetIsNetworkAvailable

The following example uses the GetIsNetworkAvailable method to determine if a network connection is available.

if (System.Net.NetworkInformation.NetworkInterface.GetIsNetworkAvailable())
{
    System.Windows.MessageBox.Show("This computer is connected to the internet");
}
else
{
    System.Windows.MessageBox.Show("This computer is not connected to the internet");
}

Remarks (As per MSDN): A network connection is considered to be available if any network interface is marked "up" and is not a loopback or tunnel interface.

There are many cases in which a device or computer is not connected to a useful network but is still considered available and GetIsNetworkAvailable will return true. For example, if the device running the application is connected to a wireless network that requires a proxy, but the proxy is not set, GetIsNetworkAvailable will return true. Another example of when GetIsNetworkAvailable will return true is if the application is running on a computer that is connected to a hub or router where the hub or router has lost the upstream connection.

  1. Ping a hostname on the network

Ping and PingReply classes allows an application to determine whether a remote computer is accessible over the network by getting reply from the host. These classes are available in System.Net.NetworkInformation namespace. The following example shows how to ping a host.

protected bool CheckConnectivity(string ipAddress)
{
    bool connectionExists = false;
    try
    {
        System.Net.NetworkInformation.Ping pingSender = new System.Net.NetworkInformation.Ping();
        System.Net.NetworkInformation.PingOptions options = new System.Net.NetworkInformation.PingOptions();
        options.DontFragment = true;
        if (!string.IsNullOrEmpty(ipAddress))
        {
            System.Net.NetworkInformation.PingReply reply = pingSender.Send(ipAddress);
            connectionExists = reply.Status == 
System.Net.NetworkInformation.IPStatus.Success ? true : false;
        }
    }
    catch (PingException ex)
    {
        Logger.LogException(ex.Message, ex);
    }
    return connectionExists;
}

Remarks (As per MSDN): Applications use the Ping class to detect whether a remote computer is reachable. Network topology can determine whether Ping can successfully contact a remote host. The presence and configuration of proxies, network address translation (NAT) equipment, or firewalls can prevent Ping from succeeding. A successful Ping indicates only that the remote host can be reached on the network; the presence of higher level services (such as a Web server) on the remote host is not guaranteed.

Comments/Suggestions are invited. Happy coding......!

Hibernate openSession() vs getCurrentSession()

As explained in this forum post, 1 and 2 are related. If you set hibernate.current_session_context_class to thread and then implement something like a servlet filter that opens the session - then you can access that session anywhere else by using the SessionFactory.getCurrentSession().

SessionFactory.openSession() always opens a new session that you have to close once you are done with the operations. SessionFactory.getCurrentSession() returns a session bound to a context - you don't need to close this.

If you are using Spring or EJBs to manage transactions you can configure them to open / close sessions along with the transactions.

You should never use one session per web app - session is not a thread safe object - cannot be shared by multiple threads. You should always use "one session per request" or "one session per transaction"

Foreach with JSONArray and JSONObject

Seems like you can't iterate through JSONArray with a for each. You can loop through your JSONArray like this:

for (int i=0; i < arr.length(); i++) {
    arr.getJSONObject(i);
}

Source

How to make custom error pages work in ASP.NET MVC 4

I would Recommend to use Global.asax.cs File.

 protected void Application_Error(Object sender, EventArgs e)
{
    var exception = Server.GetLastError();
    if (exception is HttpUnhandledException)
    {
        Server.Transfer("~/Error.aspx");
    }
    if (exception != null)
    {
        Server.Transfer("~/Error.aspx");
    }
    try
    {
        // This is to stop a problem where we were seeing "gibberish" in the
        // chrome and firefox browsers
        HttpApplication app = sender as HttpApplication;
        app.Response.Filter = null;
    }
    catch
    {
    }
}

jQuery add text to span within a div

You can use append or prepend

The .append() method inserts the specified content as the last child of each element in the jQuery collection (To insert it as the first child, use .prepend()).

$("#tagscloud span").append(second);
$("#tagscloud span").append(third);
$("#tagscloud span").prepend(first);

Share cookie between subdomain and domain

Please everyone note that you can set a cookie from a subdomain on a domain.

(sent in the response for requesting subdomain.mydomain.com)

Set-Cookie: name=value; Domain=mydomain.com // GOOD

But you CAN'T set a cookie from a domain on a subdomain.

(sent in the response for requesting mydomain.com)

Set-Cookie: name=value; Domain=subdomain.mydomain.com // Browser rejects cookie

WHY ?

According to the specifications RFC 6265 section 5.3.6 Storage Model

If the canonicalized request-host does not domain-match the domain-attribute: Ignore the cookie entirely and abort these steps.

and RFC 6265 section 5.1.3 Domain Matching

Domain Matching

A string domain-matches a given domain string if at least one of the following conditions hold:

  1. The domain string and the string are identical. (Note that both the domain string and the string will have been canonicalized to lower case at this point.)

  2. All of the following conditions hold:

    • The domain string is a suffix of the string.

    • The last character of the string that is not included in the domain string is a %x2E (".") character.

    • The string is a host name (i.e., not an IP address).

So "subdomain.mydomain.com" domain-matches "mydomain.com", but "mydomain.com" does NOT domain-match "subdomain.mydomain.com"

Check this answer also.

Copy directory to another directory using ADD command

Indeed ADD go /usr/local/ will add content of go folder and not the folder itself, you can use Thomasleveil solution or if that did not work for some reason you can change WORKDIR to /usr/local/ then add your directory to it like:

WORKDIR /usr/local/
COPY go go/

or

WORKDIR /usr/local/go
COPY go ./

But if you want to add multiple folders, it will be annoying to add them like that, the only solution for now as I see it from my current issue is using COPY . . and exclude all unwanted directories and files in .dockerignore, let's say I got folders and files:

- src 
- tmp 
- dist 
- assets 
- go 
- justforfun 
- node_modules 
- scripts 
- .dockerignore 
- Dockerfile 
- headache.lock 
- package.json 

and I want to add src assets package.json justforfun go so:

in Dockerfile:

FROM galaxy:latest

WORKDIR /usr/local/
COPY . .

in .dockerignore file:

node_modules
headache.lock
tmp
dist

Or for more fun (or you like to confuse more people make them suffer as well :P) can be:

*
!src 
!assets 
!go 
!justforfun 
!scripts 
!package.json 

In this way you ignore everything, but excluding what you want to be copied or added only from "ignore list".

It is a late answer but adding more ways to do the same covering even more cases.

What is the difference between the 'COPY' and 'ADD' commands in a Dockerfile?

Since Docker 17.05 COPY is used with the --from flag in multi-stage builds to copy artifacts from previous build stages to the current build stage.

from the documentation

Optionally COPY accepts a flag --from=<name|index> that can be used to set the source location to a previous build stage (created with FROM .. AS ) that will be used instead of a build context sent by the user.

Pure CSS scroll animation

You can do it with anchor tags using css3 :target pseudo-selector, this selector is going to be triggered when the element with the same id as the hash of the current URL get an match. Example

Knowing this, we can combine this technique with the use of proximity selectors like "+" and "~" to select any other element through the target element who id get match with the hash of the current url. An example of this would be something like what you are asking.

favicon.png vs favicon.ico - why should I use PNG instead of ICO?

Some social tools like Google+ use a simple method to get a favicon for external links, fetching http://your.domainname.com/favicon.ico

Since they don't prefetch the HTML content, the <link> tag will not work. In this case, you might want to use a mod_rewrite rule or just place the file in the default location.

How to align 3 divs (left/center/right) inside another div?

There are several tricks available for aligning the elements.

01. Using Table Trick

_x000D_
_x000D_
.container{_x000D_
  display:table;_x000D_
 }_x000D_
_x000D_
.left{_x000D_
  background:green;_x000D_
  display:table-cell;_x000D_
  width:33.33vw;_x000D_
}_x000D_
_x000D_
.center{_x000D_
  background:gold;_x000D_
  display:table-cell;_x000D_
  width:33.33vw;_x000D_
}_x000D_
_x000D_
.right{_x000D_
  background:gray;_x000D_
  display:table-cell;_x000D_
  width:33.33vw;_x000D_
}
_x000D_
<div class="container">_x000D_
  <div class="left">_x000D_
    Left_x000D_
  </div>_x000D_
  <div class="center">_x000D_
    Center_x000D_
  </div>_x000D_
  <div class="right">_x000D_
    Right_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

02. Using Flex Trick

_x000D_
_x000D_
.container{_x000D_
  display:flex;_x000D_
  justify-content: center;_x000D_
  align-items: center;_x000D_
   }_x000D_
_x000D_
.left{_x000D_
  background:green;_x000D_
  width:33.33vw;_x000D_
}_x000D_
_x000D_
.center{_x000D_
  background:gold;_x000D_
   width:33.33vw;_x000D_
}_x000D_
_x000D_
.right{_x000D_
  background:gray;_x000D_
   width:33.33vw;_x000D_
}
_x000D_
<div class="container">_x000D_
  <div class="left">_x000D_
    Left_x000D_
  </div>_x000D_
  <div class="center">_x000D_
    Center_x000D_
  </div>_x000D_
  <div class="right">_x000D_
    Right_x000D_
  </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

03. Using Float Trick

_x000D_
_x000D_
.left{_x000D_
  background:green;_x000D_
  width:100px;_x000D_
  float:left;_x000D_
}_x000D_
_x000D_
.center{_x000D_
   background:gold;_x000D_
   width:100px;_x000D_
   float:left;_x000D_
}_x000D_
_x000D_
.right{_x000D_
   background:gray;_x000D_
   width:100px;_x000D_
   float:left;_x000D_
}
_x000D_
<div class="container">_x000D_
  <div class="left">_x000D_
    Left_x000D_
  </div>_x000D_
  <div class="center">_x000D_
    Center_x000D_
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