Programs & Examples On #Validationrules

A validation rule is a criterion used in the process of data validation, after the data has been encoded onto an input medium. This is distinct from formal verification, where the operation of a program is determined to be correct per the specification.

WPF Data Binding and Validation Rules Best Practices

personaly, i'm using exceptions to handle validation. it requires following steps:

  1. in your data binding expression, you need to add "ValidatesOnException=True"
  2. in you data object you are binding to, you need to add DependencyPropertyChanged handler where you check if new value fulfills your conditions - if not - you restore to the object old value (if you need to) and you throw exception.
  3. in your control template you use for displaying invalid value in the control, you can access Error collection and display exception message.

the trick here, is to bind only to objects which derive from DependencyObject. simple implementation of INotifyPropertyChanged wouldn't work - there is a bug in the framework, which prevents you from accessing error collection.

JsonParseException : Illegal unquoted character ((CTRL-CHAR, code 10)

On Salesforce platform this error is caused by /, the solution is to escape these as //.

Add marker to Google Map on Click

Currently the method to add the listener to the map would be

map.addListener('click', function(e) {
    placeMarker(e.latLng, map);
});

And not

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

Reference

Checking if output of a command contains a certain string in a shell script

A clean if/else conditional shell script:

if ./somecommand | grep -q 'some_string'; then
  echo "exists"
else
  echo "doesn't exist"
fi

Bootstrap how to get text to vertical align in a div container

HTML:

First, we will need to add a class to your text container so that we can access and style it accordingly.

<div class="col-xs-5 textContainer">
     <h3 class="text-left">Link up with other gamers all over the world who share the same tastes in games.</h3>
</div>

CSS:

Next, we will apply the following styles to align it vertically, according to the size of the image div next to it.

.textContainer { 
    height: 345px; 
    line-height: 340px;
}

.textContainer h3 {
    vertical-align: middle;
    display: inline-block;
}

All Done! Adjust the line-height and height on the styles above if you believe that it is still slightly out of align.

WORKING EXAMPLE

How do I make a splash screen?

A Splash Screnn, by default, does not automatically make your Application look more professional. A professionally designed Splash Screen has a possibility of making your Application look more professional, but if you do not know how to write one then how professional will the rest of your Application actually be.

About the only reason (excuse) to have a Splash Screen is because you are doing a massive amount of Calculations or are waiting for GPS/WiFi to startup because your Application relies on that prior to it starting. Without the result of those Calculations or access to GPS/WiFi (etc.) your Application is dead in the water, thus you feel you need a Splash Screen, and MUST block the view of the Screen for any other running Programs (including the Background).

Such a Splash Screen ought to look like your Full Screen Application to give the impression that it has already initialized, then after the lengthy calculations are completed the final details could be filled in (the Image tweaked). The chance of that being the case or that it is the only way the Program could be designed is mighty small.

It would be better to allow the User (and the rest of the OS) to do something else while they wait rather than design your Program to be dependant on something that will take a while (when the duration of the wait is uncertain).

There are Icons on your Phone already that say that GPS/WiFi is starting. The time or space taken up by the Splash Screen could be spent loading pre-calculations or actually doing the Calculations. See the first Link below for the problems you create and what must be considered.

If you absolutely must wait for these Calculations or GPS/WiFi it would be best to simply let the Application start and have a pop-up that says that it is necessary to wait for the Calculations (a TEXTUAL "Initializing" Message is fine). The wait for GPS/WiFi is expected (if they were not enabled in another Program already) so announcing their wait times are unnecessary.

Remember that when the Splash Screen starts your Program IS actually running already, all you are doing is delaying the use of your Program and hogging the CPU/GPU to do something that most do not feel is necessary.

We had better really want to wait and see your Splash Screen every time we start your Program or WE will not feel it is very professionally written. Making the Splash Screen FULL Screen and a duplicate of the actual Program's Screen (so we think it is initialized when in fact it has not) MIGHT accomplish your goal (of making your Program look more professional) but I would not bet much on that.

Why not to do it: http://cyrilmottier.com/2012/05/03/splash-screens-are-evil-dont-use-them/

How to do it: https://encrypted.google.com/search?q=Android+splash+screen+source

So there is a good reason not to do it but IF you are certain that somehow your situation falls outside those examples then the means to do it is given above. Be certain that it really does make your Application look more professional or you have defeated the only reason you gave for doing this.

It is like a YouTube Channel that starts every Video with a lengthy Graphic Intro (and Outro) or feels the need to tell a Joke or explain what happened during the past week (when it is not a Comedy or LifeStyles Channel). Just show the show ! (Just run the Program).

PHP call Class method / function

Create object for the class and call, if you want to call it from other pages.

$obj = new Functions();

$var = $obj->filter($_GET['params']);

Or inside the same class instances [ methods ], try this.

$var = $this->filter($_GET['params']);

Shell equality operators (=, ==, -eq)

It's the other way around: = and == are for string comparisons, -eq is for numeric ones. -eq is in the same family as -lt, -le, -gt, -ge, and -ne, if that helps you remember which is which.

== is a bash-ism, by the way. It's better to use the POSIX =. In bash the two are equivalent, and in plain sh = is the only one guaranteed to work.

$ a=foo
$ [ "$a" = foo ]; echo "$?"       # POSIX sh
0
$ [ "$a" == foo ]; echo "$?"      # bash specific
0
$ [ "$a" -eq foo ]; echo "$?"     # wrong
-bash: [: foo: integer expression expected
2

(Side note: Quote those variable expansions! Do not leave out the double quotes above.)

If you're writing a #!/bin/bash script then I recommend using [[ instead. The doubled form has more features, more natural syntax, and fewer gotchas that will trip you up. Double quotes are no longer required around $a, for one:

$ [[ $a == foo ]]; echo "$?"      # bash specific
0

See also:

JavaScript alert box with timer

May be it's too late but the following code works fine

document.getElementById('alrt').innerHTML='<b>Please wait, Your download will start soon!!!</b>'; 
setTimeout(function() {document.getElementById('alrt').innerHTML='';},5000);

<div id='alrt' style="fontWeight = 'bold'"></div>

Equivalent of LIMIT and OFFSET for SQL Server?

Another sample :

declare @limit int 
declare @offset int 
set @offset = 2;
set @limit = 20;
declare @count int
declare @idxini int 
declare @idxfim int 
select @idxfim = @offset * @limit
select @idxini = @idxfim - (@limit-1);
WITH paging AS
    (
        SELECT 
             ROW_NUMBER() OVER (order by object_id) AS rowid, *
        FROM 
            sys.objects 
    )
select *
    from 
        (select COUNT(1) as rowqtd from paging) qtd, 
            paging 
    where 
        rowid between @idxini and @idxfim
    order by 
        rowid;

When should an IllegalArgumentException be thrown?

Any API should check the validity of the every parameter of any public method before executing it:

void setPercentage(int pct, AnObject object) {
    if( pct < 0 || pct > 100) {
        throw new IllegalArgumentException("pct has an invalid value");
    }
    if (object == null) {
        throw new IllegalArgumentException("object is null");
    }
}

They represent 99.9% of the times errors in the application because it is asking for impossible operations so in the end they are bugs that should crash the application (so it is a non recoverable error).

In this case and following the approach of fail fast you should let the application finish to avoid corrupting the application state.

When using a Settings.settings file in .NET, where is the config actually stored?

If your settings file is in a web app, they will be in teh web.config file (right below your project. If they are in any other type of project, they will be in the app.config file (also below your project).

Edit

As is pointed out in the comments: your design time application settings are in an app.config file for applications other than web applications. When you build, the app.config file is copied to the output directory, and will be named yourexename.exe.config. At runtime, only the file named yourexename.exe.config will be read.

Adding a HTTP header to the Angular HttpClient doesn't send the header, why?

I struggled with this for a long time. I am using Angular 6 and I found that

let headers = new HttpHeaders();
headers = headers.append('key', 'value');

did not work. But what did work was

let headers = new HttpHeaders().append('key', 'value');

did, which makes sense when you realize they are immutable. So having created a header you can't add to it. I haven't tried it, but I suspect

let headers = new HttpHeaders();
let headers1 = headers.append('key', 'value');

would work too.

I can't install pyaudio on Windows? How to solve "error: Microsoft Visual C++ 14.0 is required."?

I have got the same error as :

error: Microsoft Visual C++ 14.0 is required. Get it with "Microsoft Visual C++ Build Tools": https://visualstudio.microsoft.com/downloads/

As, said by @Agaline, i download the outside wheel from this Christoph Gohlke.

If your is Python 3.7 then try to PyAudio-0.2.11-cp37-cp37m-win_amd64.whl and use command as, go to the download directroy and:

pip install PyAudio-0.2.11-cp37-cp37m-win_amd64.whl and it works.

Get user profile picture by Id

Use url as:https://graph.facebook.com/user_id/picture?type=square in src of img tag. type may be small,large.

Cant get text of a DropDownList in code - can get value but not text

AppendDataBoundItems="true" needs to be set.

Convert PDF to PNG using ImageMagick

Reducing the image size before output results in something that looks sharper, in my case:

convert -density 300 a.pdf -resize 25% a.png

Print text instead of value from C enum

There is another solution: Create your own dynamic enumeration class. Means you have a struct and some function to create a new enumeration, which stores the elements in a struct and each element has a string for the name. You also need some type to store a individual elements, functions to compare them and so on. Here is an example:

#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>


struct Enumeration_element_T
{
  size_t index;
  struct Enumeration_T *parrent;
  char *name;
};

struct Enumeration_T
{
  size_t len;
  struct Enumeration_element_T elements[];
};
  


void enumeration_delete(struct Enumeration_T *self)
{
  if(self)
  {
    while(self->len--)
    {
      free(self->elements[self->len].name);
    }
    free(self);
  }
}

struct Enumeration_T *enumeration_create(size_t len,...)
{
  //We do not check for size_t overflows, but we should.
  struct Enumeration_T *self=malloc(sizeof(self)+sizeof(self->elements[0])*len);
  if(!self)
  {
    return NULL;
  }
  self->len=0;
  va_list l; 
  va_start(l,len);
  for(size_t i=0;i<len;i++)
  {
    const char *name=va_arg(l,const char *);
    self->elements[i].name=malloc(strlen(name)+1);
    if(!self->elements[i].name)
    {
      enumeration_delete(self);
      return NULL;
    }
    strcpy(self->elements[i].name,name);
    self->len++;
  }
  return self;
}


bool enumeration_isEqual(struct Enumeration_element_T *a,struct Enumeration_element_T *b)
{
  return a->parrent==b->parrent && a->index==b->index;
}

bool enumeration_isName(struct Enumeration_element_T *a, const char *name)
{
  return !strcmp(a->name,name);
}

const char *enumeration_getName(struct Enumeration_element_T *a)
{
  return a->name;
}

struct Enumeration_element_T *enumeration_getFromName(struct Enumeration_T *self, const char *name)
{
  for(size_t i=0;i<self->len;i++)
  {
    if(enumeration_isName(&self->elements[i],name))
    {
      return &self->elements[i];
    }
  }
  return NULL;
}
  
struct Enumeration_element_T *enumeration_get(struct Enumeration_T *self, size_t index)
{
  return &self->elements[index];
}

size_t enumeration_getCount(struct Enumeration_T *self)
{
  return self->len;
}

bool enumeration_isInRange(struct Enumeration_T *self, size_t index)
{
  return index<self->len;
}



int main(void)
{
  struct Enumeration_T *weekdays=enumeration_create(7,"Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday");
  if(!weekdays)
  {
    return 1;
  }
    
  printf("Please enter the day of the week (0 to 6)\n");
  size_t j = 0;
  if(scanf("%zu",&j)!=1)
  {
    enumeration_delete(weekdays);
    return 1;
  }
  // j=j%enumeration_getCount(weekdays); //alternative way to make sure j is in range
  if(!enumeration_isInRange(weekdays,j))
  {
    enumeration_delete(weekdays);
    return 1;
  }

  struct Enumeration_element_T *day=enumeration_get(weekdays,j);
  

  printf("%s\n",enumeration_getName(day));
  
  enumeration_delete(weekdays);

  return 0;
}

The functions of enumeration should be in their own translation unit, but i combined them here to make it simpler.

The advantage is that this solution is flexible, follows the DRY principle, you can store information along with each element, you can create new enumerations during runtime and you can add new elements during runtime. The disadvantage is that this is complex, needs dynamic memory allocation, can't be used in switch-case, needs more memory and is slower. The question is if you should not use a higher level language in cases where you need this.

mysqli_select_db() expects parameter 1 to be mysqli, string given

// 2. Select a database to use 
$db_select = mysqli_select_db($connection, DB_NAME);
if (!$db_select) {
    die("Database selection failed: " . mysqli_error($connection));
}

You got the order of the arguments to mysqli_select_db() backwards. And mysqli_error() requires you to provide a connection argument. mysqli_XXX is not like mysql_XXX, these arguments are no longer optional.

Note also that with mysqli you can specify the DB in mysqli_connect():

$connection = mysqli_connect(DB_SERVER, DB_USER, DB_PASS, DB_NAME);
if (!$connection) {
  die("Database connection failed: " . mysqli_connect_error();
}

You must use mysqli_connect_error(), not mysqli_error(), to get the error from mysqli_connect(), since the latter requires you to supply a valid connection.

You have not concluded your merge (MERGE_HEAD exists)

We can use git merge --continue with git version 2.12 and above to continue your merging after resolved the conflict. Can see this answer

jQuery checkbox checked state changed event

If your intention is to attach event only on checked checkboxes (so it would fire when they are unchecked and checked later again) then this is what you want.

$(function() {
    $("input[type='checkbox']:checked").change(function() {

    })
})

if your intention is to attach event to all checkboxes (checked and unchecked)

$(function() {
    $("input[type='checkbox']").change(function() {

    })
})

if you want it to fire only when they are being checked (from unchecked) then @James Allardice answer above.

BTW input[type='checkbox']:checked is CSS selector.

WPF Binding to parent DataContext

I dont know about XamGrid but that's what i'll do with a standard wpf DataGrid:

<DataGrid>
    <DataGrid.Columns>
        <DataGridTemplateColumn>
            <DataGridTemplateColumn.CellTemplate>
                <DataTemplate>
                    <TextBlock Text="{Binding DataContext.MyProperty, RelativeSource={RelativeSource AncestorType=MyUserControl}}"/>
                </DataTemplate>
            </DataGridTemplateColumn.CellTemplate>
            <DataGridTemplateColumn.CellEditingTemplate>
                <DataTemplate>
                    <TextBox Text="{Binding DataContext.MyProperty, RelativeSource={RelativeSource AncestorType=MyUserControl}}"/>
                </DataTemplate>
            </DataGridTemplateColumn.CellEditingTemplate>
        </DataGridTemplateColumn>
    </DataGrid.Columns>
</DataGrid>

Since the TextBlock and the TextBox specified in the cell templates will be part of the visual tree, you can walk up and find whatever control you need.

Open Facebook Page in Facebook App (if installed) on Android

"fb://page/ does not work with newer versions of the FB app. You should use fb://facewebmodal/f?href= for newer versions.

This is a full fledged working code currently live in one of my apps:

public static String FACEBOOK_URL = "https://www.facebook.com/YourPageName";
public static String FACEBOOK_PAGE_ID = "YourPageName";

//method to get the right URL to use in the intent
public String getFacebookPageURL(Context context) {
        PackageManager packageManager = context.getPackageManager();
        try {
            int versionCode = packageManager.getPackageInfo("com.facebook.katana", 0).versionCode;
            if (versionCode >= 3002850) { //newer versions of fb app
                return "fb://facewebmodal/f?href=" + FACEBOOK_URL;
            } else { //older versions of fb app
                return "fb://page/" + FACEBOOK_PAGE_ID;
            }
        } catch (PackageManager.NameNotFoundException e) {
            return FACEBOOK_URL; //normal web url
        }
    }

This method will return the correct url for app if installed or web url if app is not installed.

Then start an intent as follows:

Intent facebookIntent = new Intent(Intent.ACTION_VIEW);
String facebookUrl = getFacebookPageURL(this);
facebookIntent.setData(Uri.parse(facebookUrl));
startActivity(facebookIntent);

That's all you need.

malloc for struct and pointer in C

Few points

struct Vector y = (struct Vector*)malloc(sizeof(struct Vector)); is wrong

it should be struct Vector *y = (struct Vector*)malloc(sizeof(struct Vector)); since y holds pointer to struct Vector.

1st malloc() only allocates memory enough to hold Vector structure (which is pointer to double + int)

2nd malloc() actually allocate memory to hold 10 double.

curl -GET and -X GET

By default you use curl without explicitly saying which request method to use. If you just pass in a HTTP URL like curl http://example.com it will use GET. If you use -d or -F curl will use POST, -I will cause a HEAD and -T will make it a PUT.

If for whatever reason you're not happy with these default choices that curl does for you, you can override those request methods by specifying -X [WHATEVER]. This way you can for example send a DELETE by doing curl -X DELETE [URL].

It is thus pointless to do curl -X GET [URL] as GET would be used anyway. In the same vein it is pointless to do curl -X POST -d data [URL]... But you can make a fun and somewhat rare request that sends a request-body in a GET request with something like curl -X GET -d data [URL].

Digging deeper

curl -GET (using a single dash) is just wrong for this purpose. That's the equivalent of specifying the -G, -E and -T options and that will do something completely different.

There's also a curl option called --get to not confuse matters with either. It is the long form of -G, which is used to convert data specified with -d into a GET request instead of a POST.

(I subsequently used my own answer here to populate the curl FAQ to cover this.)

Warnings

Modern versions of curl will inform users about this unnecessary and potentially harmful use of -X when verbose mode is enabled (-v) - to make users aware. Further explained and motivated in this blog post.

-G converts a POST + body to a GET + query

You can ask curl to convert a set of -d options and instead of sending them in the request body with POST, put them at the end of the URL's query string and issue a GET, with the use of `-G. Like this:

curl -d name=daniel -d grumpy=yes -G https://example.com/

Set iframe content height to auto resize dynamically

Simple solution:

<iframe onload="this.style.height=this.contentWindow.document.body.scrollHeight + 'px';" ...></iframe>

This works when the iframe and parent window are in the same domain. It does not work when the two are in different domains.

Getting strings recognized as variable names in R

Without any example data, it really is difficult to know exactly what you are wanting. For instance, I can't at all divine what your object set (or is it sets) looks like.

That said, does the following help at all?

set1 <- data.frame(x = 4:6, y = 6:4, z = c(1, 3, 5))

plot(1:10, type="n")
XX <- "set1"
with(eval(as.symbol(XX)), symbols(x, y, circles = z, add=TRUE))

EDIT:

Now that I see your real task, here is a one-liner that'll do everything you want without requiring any for() loops:

with(dat, symbols(sq, cu, circles = num,
                  bg = c("red", "blue")[(num>5) + 1]))

The one bit of code that may feel odd is the bit specifying the background color. Try out these two lines to see how it works:

c(TRUE, FALSE) + 1
# [1] 2 1
c("red", "blue")[c(F, F, T, T) + 1]
# [1] "red"  "red"  "blue" "blue"

Filter Excel pivot table using VBA

In Excel 2007 onwards, you can use the much simpler code using a more precise reference:

dim pvt as PivotTable
dim pvtField as PivotField

set pvt = ActiveSheet.PivotTables("PivotTable2")
set pvtField = pvt.PivotFields("SavedFamilyCode")

pvtField.PivotFilters.Add xlCaptionEquals, Value1:= "K123223"

No provider for Http StaticInjectorError

Add these two file in your app.module.ts

import { FileTransfer } from '@ionic-native/file-transfer';
import { File } from '@ionic-native/file';

after that declare these to in provider..

providers: [
    Api,
    Items,
    User,
    Camera,
    File,
    FileTransfer];

This is work for me.

EXC_BAD_ACCESS signal received

An EXC_BAD_ACCESS signal is the result of passing an invalid pointer to a system call. I got one just earlier today with a test program on OS X - I was passing an uninitialized variable to pthread_join(), which was due to an earlier typo.

I'm not familiar with iPhone development, but you should double-check all your buffer pointers that you're passing to system calls. Crank up your compiler's warning level all the way (with gcc, use the -Wall and -Wextra options). Enable as many diagnostics on the simulator/debugger as possible.

What is the meaning of curly braces?

Dictionaries in Python are data structures that store key-value pairs. You can use them like associative arrays. Curly braces are used when declaring dictionaries:

d = {'One': 1, 'Two' : 2, 'Three' : 3 }
print d['Two'] # prints "2"

Curly braces are not used to denote control levels in Python. Instead, Python uses indentation for this purpose.

I think you really need some good resources for learning Python in general. See https://stackoverflow.com/q/175001/10077

Git: copy all files in a directory from another branch

As you are not trying to move the files around in the tree, you should be able to just checkout the directory:

git checkout master -- dirname

Producer/Consumer threads using a Queue

OK, as others note, the best thing to do is to use java.util.concurrent package. I highly recommend "Java Concurrency in Practice". It's a great book that covers almost everything you need to know.

As for your particular implementation, as I noted in the comments, don't start Threads from Constructors -- it can be unsafe.

Leaving that aside, the second implementation seem better. You don't want to put queues in static fields. You are probably just loosing flexibility for nothing.

If you want to go ahead with your own implementation (for learning purpose I guess?), supply a start() method at least. You should construct the object (you can instantiate the Thread object), and then call start() to start the thread.

Edit: ExecutorService have their own queue so this can be confusing.. Here's something to get you started.

public class Main {
    public static void main(String[] args) {
        //The numbers are just silly tune parameters. Refer to the API.
        //The important thing is, we are passing a bounded queue.
        ExecutorService consumer = new ThreadPoolExecutor(1,4,30,TimeUnit.SECONDS,new LinkedBlockingQueue<Runnable>(100));

        //No need to bound the queue for this executor.
        //Use utility method instead of the complicated Constructor.
        ExecutorService producer = Executors.newSingleThreadExecutor();

        Runnable produce = new Produce(consumer);
        producer.submit(produce);   
    }
}

class Produce implements Runnable {
    private final ExecutorService consumer;

    public Produce(ExecutorService consumer) {
        this.consumer = consumer;
    }

    @Override
    public void run() {
        Pancake cake = Pan.cook();
        Runnable consume = new Consume(cake);
        consumer.submit(consume);
    }
}

class Consume implements Runnable {
    private final Pancake cake;

    public Consume(Pancake cake){
        this.cake = cake;
    }

    @Override
    public void run() {
        cake.eat();
    }
}

Further EDIT: For producer, instead of while(true), you can do something like:

@Override
public void run(){
    while(!Thread.currentThread().isInterrupted()){
        //do stuff
    }
}

This way you can shutdown the executor by calling .shutdownNow(). If you'd use while(true), it won't shutdown.

Also note that the Producer is still vulnerable to RuntimeExceptions (i.e. one RuntimeException will halt the processing)

Failed to load JavaHL Library

I Just installed Mountain Lion and had the same problem I use FLashBuilder (which is 32bit) and MountainLion is 64bit, which means by default MacPorts installs everything as 64bit. The version of subclipse I use is 1.8 As i had already installed Subversion and JavaHLBindings I just ran this command:

 sudo port upgrade --enforce-variants active +universal 

This made mac ports go through everything already installed and also install the 32bit version.

I then restarted FlashBuilder and it no longer showed any JavaHL errors.

Animate background image change with jQuery

It can be done by jquery and css. i did it in a way that can be used in dynamic situations , you just have to change background-image in jquery and it will do every thing , also you can change the time in css.

The fiddle : https://jsfiddle.net/Naderial/zohfvqz7/

Html:

<div class="test">

CSS :

.test {
  /* as default, we set a background-image , but it is not nessesary */
  background-image: url(http://lorempixel.com/400/200);
  width: 200px;
  height: 200px;
  /* we set transition to 'all' properies - but you can use it just for background image either - by default the time is set to 1 second, you can change it yourself*/
  transition: linear all 1s;
  /* if you don't use delay , background will disapear and transition will start from a white background - you have to set the transition-delay the same as transition time OR more , so there won't be any problems */
  -webkit-transition-delay: 1s;/* Safari */
  transition-delay: 1s;
}

JS:

$('.test').click(function() {
  //you can use all properties : background-color  - background-image ...
  $(this).css({
    'background-image': 'url(http://lorempixel.com/400/200)'
  });
});

Refer to a cell in another worksheet by referencing the current worksheet's name?

Unless you want to go the VBA route to work out the Tab name, the Excel formula is fairly ugly based upon Mid functions, etc. But both these methods can be found here if you want to go that way.

Rather, the way I would do it is:

1) Make one cell on your sheet named, for example, Reference_Sheet and put in that cell the value "Jan Item" for example.

2) Now, use the Indirect function like:

=INDIRECT(Reference_Sheet&"!J3") 

3) Now, for each month's sheet, you just have to change that one Reference_Sheet cell.

Hope this gives you what you're looking for!

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

DEMO

Basically, you want to loop through each direct descendent of the old-parent node, and move it to the new parent. Any children of a direct descendent will get moved with it.

var newParent = document.getElementById('new-parent');
var oldParent = document.getElementById('old-parent');

while (oldParent.childNodes.length > 0) {
    newParent.appendChild(oldParent.childNodes[0]);
}

Access parent's parent from javascript object

I simply added in first function

parentThis = this;

and use parentThis in subfunction. Why? Because in JavaScript, objects are soft. A new member can be added to a soft object by simple assignment (not like ie. Java where classical objects are hard. The only way to add a new member to a hard object is to create a new class) More on this here: http://www.crockford.com/javascript/inheritance.html

And also at the end you don't have to kill or destroy the object. Why I found here: http://bytes.com/topic/javascript/answers/152552-javascript-destroy-object

Hope this helps

UnsupportedClassVersionError unsupported major.minor version 51.0 unable to load class

java_home environment variable should point to the location of the proper version of java installation directory, so that tomcat starts with the right version. for example it you built the project with java 1.7 , then make sure that JAVA_HOME environment variable points to the jdk 1.7 installation directory in your machine.

I had same problem , when i deploy the war in tomcat and run, the link throws the error. But pointing the variable - JAVA_HOME to jdk 1.7 resolved the issue, as my war file was built in java 1.7 environment.

How do I divide in the Linux console?

Example of integer division using bash to divide $a by $b:

echo $((a/b))

Delete column from SQLite table

For SQLite3 c++ :

void GetTableColNames( tstring sTableName , std::vector<tstring> *pvsCols )
{
    UASSERT(pvsCols);

    CppSQLite3Table table1;

    tstring sDML = StringOps::std_sprintf(_T("SELECT * FROM %s") , sTableName.c_str() );



    table1 = getTable( StringOps::tstringToUTF8string(sDML).c_str() );

    for ( int nCol = 0 ; nCol < table1.numFields() ; nCol++ )
    {
        const char* pch1 = table1.fieldName(nCol);  

        pvsCols->push_back( StringOps::UTF8charTo_tstring(pch1));
    }
}


bool ColExists( tstring sColName )
{
    bool bColExists = true;

    try
    {
        tstring sQuery = StringOps::std_sprintf(_T("SELECT %s FROM MyOriginalTable LIMIT 1;") , sColName.c_str() );

        ShowVerbalMessages(false);

        CppSQLite3Query q = execQuery( StringOps::tstringTo_stdString(sQuery).c_str() );

        ShowVerbalMessages(true);
    }
    catch (CppSQLite3Exception& e)
    {
        bColExists = false;
    }

    return bColExists;
}

void DeleteColumns( std::vector<tstring> *pvsColsToDelete )
{
    UASSERT(pvsColsToDelete);

    execDML( StringOps::tstringTo_stdString(_T("begin transaction;")).c_str() );


    std::vector<tstring> vsCols;
    GetTableColNames( _T("MyOriginalTable") , &vsCols );


    CreateFields( _T("TempTable1") , false );

    tstring sFieldNamesSeperatedByCommas;

    for ( int nCol = 0 ; nCol < vsCols.size() ; nCol++ )
    {

        tstring sColNameCurr = vsCols.at(nCol);

        bool bUseCol = true;

        for ( int nColsToDelete = 0; nColsToDelete < pvsColsToDelete->size() ; nColsToDelete++ )
        {
            if ( pvsColsToDelete->at(nColsToDelete) == sColNameCurr )
            {
                bUseCol = false;
                break;
            }
        }

        if ( bUseCol )
            sFieldNamesSeperatedByCommas+= (sColNameCurr + _T(","));

    }

    if ( sFieldNamesSeperatedByCommas.at( int(sFieldNamesSeperatedByCommas.size()) - 1) == _T(','))
        sFieldNamesSeperatedByCommas.erase( int(sFieldNamesSeperatedByCommas.size()) - 1 );

    tstring sDML;


    sDML = StringOps::std_sprintf(_T("insert into TempTable1 SELECT %s FROM MyOriginalTable;\n") , sFieldNamesSeperatedByCommas.c_str() );
    execDML( StringOps::tstringTo_stdString(sDML).c_str() );

    sDML = StringOps::std_sprintf(_T("ALTER TABLE MyOriginalTable RENAME TO MyOriginalTable_old\n") );
    execDML( StringOps::tstringTo_stdString(sDML).c_str() );

    sDML = StringOps::std_sprintf(_T("ALTER TABLE TempTable1 RENAME TO MyOriginalTable\n") );
    execDML( StringOps::tstringTo_stdString(sDML).c_str() );


    sDML = ( _T("DROP TABLE MyOriginalTable_old;") );   
    execDML( StringOps::tstringTo_stdString(sDML).c_str() );


    execDML( StringOps::tstringTo_stdString(_T("commit transaction;")).c_str() );   
}

_csv.Error: field larger than field limit (131072)

Sometimes, a row contain double quote column. When csv reader try read this row, not understood end of column and fire this raise. Solution is below:

reader = csv.reader(cf, quoting=csv.QUOTE_MINIMAL)

What is the equivalent of "!=" in Excel VBA?

Just a note. If you want to compare a string with "" ,in your case, use

If LEN(str) > 0 Then

or even just

If LEN(str) Then

instead.

Get size of a View in React Native

Here is the code to get the Dimensions of the complete view of the device.

var windowSize = Dimensions.get("window");

Use it like this:

width=windowSize.width,heigth=windowSize.width/0.565

Changing an element's ID with jQuery

I'm not sure what your goal is, but might it be better to use addClass instead? I mean an objects ID in my opinion should be static and specific to that object. If you are just trying to change it from showing on the page or something like that I would put those details in a class and then add it to the object rather then trying to change it's ID. Again, I'm saying that without understand your underlining goal.

Can someone explain how to implement the jQuery File Upload plugin?

it's 2021 and here's a fantastically easy plugin to upload anything:

https://pqina.nl/filepond/?ref=pqina

add your element:

<input type="file" 
class="filepond"
name="filepond" 
multiple 
data-allow-reorder="true"
data-max-file-size="3MB"
data-max-files="3">

Register any additional plugins:

  FilePond.registerPlugin(
FilePondPluginImagePreview,  
FilePondPluginImageExifOrientation,  
FilePondPluginFileValidateSize,  
FilePondPluginImageEdit);

Then wire in the element:

// Select the file input and use 
// create() to turn it into a pond
FilePond.create(
  document.querySelector('input'),

  // Use Doka.js as image editor
  imageEditEditor: Doka.create({
    utils: ['crop', 'filter', 'color']
  })
);

I use this with the additional Doka image editor to upload and transform images at https://www.yoodu.co.uk

crazy simple to setup and the guys who run it are great at support.

As you can tell I'm a fanboy.

Adding local .aar files to Gradle build using "flatDirs" is not working

In my case the none of the answers above worked! since I had different productFlavors just adding repositories{ flatDir{ dirs 'libs' } }

did not work! I ended up with specifying exact location of libs directory:

repositories{
flatDir{
    dirs 'src/main/libs'
}

}

Guess one should introduce flatDirs like this when there's different productFlavors in build.gradle

How do I check when a UITextField changes?

Swift 3

 textField.addTarget(self, action: #selector(ViewController.textFieldDidChange(sender:)), for: UIControlEvents.editingChanged)

DateTime's representation in milliseconds?

Using the answer of Andoma, this is what I'm doing

You can create a Struct or a Class like this one

struct Date
    {
        public static double GetTime(DateTime dateTime)
        {
            return dateTime.ToUniversalTime().Subtract(new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)).TotalMilliseconds;
        }

        public static DateTime DateTimeParse(double milliseconds)
        {
            return new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddMilliseconds(milliseconds).ToLocalTime();
        }

    }

And you can use this in your code as following

DateTime dateTime = DateTime.Now;

double total = Date.GetTime(dateTime);

dateTime = Date.DateTimeParse(total);

I hope this help you

Batch file to split .csv file

This will give you lines 1 to 20000 in newfile1.csv
and lines 20001 to the end in file newfile2.csv

It overcomes the 8K character limit per line too.

This uses a helper batch file called findrepl.bat from - https://www.dropbox.com/s/rfdldmcb6vwi9xc/findrepl.bat

Place findrepl.bat in the same folder as the batch file or on the path.

It's more robust than a plain batch file, and quicker too.

findrepl /o:1:20000 <file.csv >newfile1.csv
findrepl /o:20001   <file.csv >newfile2.csv

Spring MVC Multipart Request with JSON

This must work!

client (angular):

$scope.saveForm = function () {
      var formData = new FormData();
      var file = $scope.myFile;
      var json = $scope.myJson;
      formData.append("file", file);
      formData.append("ad",JSON.stringify(json));//important: convert to JSON!
      var req = {
        url: '/upload',
        method: 'POST',
        headers: {'Content-Type': undefined},
        data: formData,
        transformRequest: function (data, headersGetterFunction) {
          return data;
        }
      };

Backend-Spring Boot:

@RequestMapping(value = "/upload", method = RequestMethod.POST)
    public @ResponseBody
    Advertisement storeAd(@RequestPart("ad") String adString, @RequestPart("file") MultipartFile file) throws IOException {

        Advertisement jsonAd = new ObjectMapper().readValue(adString, Advertisement.class);
//do whatever you want with your file and jsonAd

Maven does not find JUnit tests to run

UPDATE:

Like @scottyseus said in the comments, starting from Maven Surefire 2.22.0 the following is sufficient:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>2.22.1</version>
</plugin>

When using JUnit 5, i ran into the same problem. Maven Surefire needs a plugin to run JUnit 5 tests. Add this to our pom.xml:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-surefire-plugin</artifactId>
    <version>2.21.0</version>
    <dependencies>
        <dependency>
            <groupId>org.junit.platform</groupId>
            <artifactId>junit-platform-surefire-provider</artifactId>
            <version>1.2.0-M1</version>
        </dependency>
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter-engine</artifactId>
            <version>5.2.0-M1</version>
        </dependency>
    </dependencies>
</plugin>

Source: https://junit.org/junit5/docs/current/user-guide/#running-tests-build-maven

Django. Override save for model

Query the database for an existing record with the same PK. Compare the file sizes and checksums of the new and existing images to see if they're the same.

Can I use VARCHAR as the PRIMARY KEY?

It is ok for sure. With just few hundred of entries, it will be fast.

You can add an unique id as as primary key (int autoincrement) ans set your coupon_code as unique. So if you need to do request in other tables it's better to use int than varchar

Install php-mcrypt on CentOS 6

For me the answer was:

1) Get the Repos from

wget http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
wget http://rpms.famillecollet.com/enterprise/remi-release-6.rpm
sudo rpm -Uvh remi-release-6*.rpm epel-release-6*.rpm

2) Install it via:

sudo yum update
sudo yum install php-mcrypt*

3) Edit the mcrypt.ini

sudo nano /etc/php.d/mcrypt.ini

add this

extension=/usr/lib64/php/modules/mcrypt.so

Finally 4) Restart your webserver:

sudo service httpd restart

I run this steps in CentOS 6.3 (64) on Azure From Microsoft Linux image

Hope it helps you.

Best Regards.

How to save a BufferedImage as a File

You can save a BufferedImage object using write method of the javax.imageio.ImageIO class. The signature of the method is like this:

public static boolean write(RenderedImage im, String formatName, File output) throws IOException

Here im is the RenderedImage to be written, formatName is the String containing the informal name of the format (e.g. png) and output is the file object to be written to. An example usage of the method for PNG file format is shown below:

ImageIO.write(image, "png", file);

Fragment onResume() & onPause() is not called on backstack

Calling ft.replace should trigger the onPause (of the replaced fragment) and onResume (of the replacing fragment).

I do notice that your code inflates login_fragment on the home fragment, and also doesn't return the views in the onCreateView. If these are typos, can you show how these fragments are being called from within your activity?

MySQL - Using If Then Else in MySQL UPDATE or SELECT Queries

Whilst you certainly can use MySQL's IF() control flow function as demonstrated by dbemerlin's answer, I suspect it might be a little clearer to the reader (i.e. yourself, and any future developers who might pick up your code in the future) to use a CASE expression instead:

UPDATE Table
SET    A = CASE
         WHEN A > 0 AND A < 1 THEN 1
         WHEN A > 1 AND A < 2 THEN 2
         ELSE A
       END
WHERE  A IS NOT NULL

Of course, in this specific example it's a little wasteful to set A to itself in the ELSE clause—better entirely to filter such conditions from the UPDATE, via the WHERE clause:

UPDATE Table
SET    A = CASE
         WHEN A > 0 AND A < 1 THEN 1
         WHEN A > 1 AND A < 2 THEN 2
       END
WHERE  (A > 0 AND A < 1) OR (A > 1 AND A < 2)

(The inequalities entail A IS NOT NULL).

Or, if you want the intervals to be closed rather than open (note that this would set values of 0 to 1—if that is undesirable, one could explicitly filter such cases in the WHERE clause, or else add a higher precedence WHEN condition):

UPDATE Table
SET    A = CASE
         WHEN A BETWEEN 0 AND 1 THEN 1
         WHEN A BETWEEN 1 AND 2 THEN 2
       END
WHERE  A BETWEEN 0 AND 2

Though, as dbmerlin also pointed out, for this specific situation you could consider using CEIL() instead:

UPDATE Table SET A = CEIL(A) WHERE A BETWEEN 0 AND 2

DataTables: Cannot read property 'length' of undefined

In my case, i had to assign my json to an attribute called aaData just like in Datatables ajax example which data looked like this.

How should I validate an e-mail address?

For an Email validation android provide some InBuilt Pattern.But it only support API level 8 and above.

Here is code for use that pattern to check email validation.

  private boolean Email_Validate(String email) 
  {
    return android.util.Patterns.EMAIL_ADDRESS.matcher(email).matches();
  }

Make sure that after execute this method you should check that if this method return true then you allow to save email and if this method return false then display message that email is "Invalid".

Hope you get your answer, Thanks you.

In WPF, what are the differences between the x:Name and Name attributes?

They are not the same thing.

x:Name is a xaml concept, used mainly to reference elements. When you give an element the x:Name xaml attribute, "the specified x:Name becomes the name of a field that is created in the underlying code when xaml is processed, and that field holds a reference to the object." (MSDN) So, it's a designer-generated field, which has internal access by default.

Name is the existing string property of a FrameworkElement, listed as any other wpf element property in the form of a xaml attribute.

As a consequence, this also means x:Name can be used on a wider range of objects. This is a technique to enable anything in xaml to be referenced by a given name.

Unable to open a file with fopen()

A little error checking goes a long way -- you can always test the value of errno or call perror() or strerror() to get more information about why the fopen() call failed.

Otherwise the suggestions about checking the path are probably correct... most likely you're not in the directory you think you are from the IDE and don't have the permissions you expect.

JSON Naming Convention (snake_case, camelCase or PascalCase)

Premise

There is no standard naming of keys in JSON. According to the Objects section of the spec:

The JSON syntax does not impose any restrictions on the strings used as names,...

Which means camelCase or snake_case should work fine.

Driving factors

Imposing a JSON naming convention is very confusing. However, this can easily be figured out if you break it down into components.

  1. Programming language for generating JSON

    • Python - snake_case
    • PHP - snake_case
    • Java - camelCase
    • JavaScript - camelCase
  2. JSON itself has no standard naming of keys

  3. Programming language for parsing JSON

    • Python - snake_case
    • PHP - snake_case
    • Java - camelCase
    • JavaScript - camelCase

Mix-match the components

  1. Python » JSON » Python - snake_case - unanimous
  2. Python » JSON » PHP - snake_case - unanimous
  3. Python » JSON » Java - snake_case - please see the Java problem below
  4. Python » JSON » JavaScript - snake_case will make sense; screw the front-end anyways
  5. Python » JSON » you do not know - snake_case will make sense; screw the parser anyways
  6. PHP » JSON » Python - snake_case - unanimous
  7. PHP » JSON » PHP - snake_case - unanimous
  8. PHP » JSON » Java - snake_case - please see the Java problem below
  9. PHP » JSON » JavaScript - snake_case will make sense; screw the front-end anyways
  10. PHP » JSON » you do not know - snake_case will make sense; screw the parser anyways
  11. Java » JSON » Python - snake_case - please see the Java problem below
  12. Java » JSON » PHP - snake_case - please see the Java problem below
  13. Java » JSON » Java - camelCase - unanimous
  14. Java » JSON » JavaScript - camelCase - unanimous
  15. Java » JSON » you do not know - camelCase will make sense; screw the parser anyways
  16. JavaScript » JSON » Python - snake_case will make sense; screw the front-end anyways
  17. JavaScript » JSON » PHP - snake_case will make sense; screw the front-end anyways
  18. JavaScript » JSON » Java - camelCase - unanimous
  19. JavaScript » JSON » JavaScript - camelCase - Original

Java problem

snake_case will still make sense for those with Java entries because the existing JSON libraries for Java are using only methods to access the keys instead of using the standard dot.syntax. This means that it wouldn't hurt that much for Java to access the snake_cased keys in comparison to the other programming language which can do the dot.syntax.

Example for Java's org.json package

JsonObject.getString("snake_cased_key")

Example for Java's com.google.gson package

JsonElement.getAsString("snake_cased_key")

Some actual implementations

Conclusions

Choosing the right JSON naming convention for your JSON implementation depends on your technology stack. There are cases where one can use snake_case, camelCase, or any other naming convention.

Another thing to consider is the weight to be put on the JSON-generator vs the JSON-parser and/or the front-end JavaScript. In general, more weight should be put on the JSON-generator side rather than the JSON-parser side. This is because business logic usually resides on the JSON-generator side.

Also, if the JSON-parser side is unknown then you can declare what ever can work for you.

Colouring plot by factor in R

The col argument in the plot function assign colors automatically to a vector of integers. If you convert iris$Species to numeric, notice you have a vector of 1,2 and 3s So you can apply this as:

plot(iris$Sepal.Length, iris$Sepal.Width, col=as.numeric(iris$Species))

Suppose you want red, blue and green instead of the default colors, then you can simply adjust it:

plot(iris$Sepal.Length, iris$Sepal.Width, col=c('red', 'blue', 'green')[as.numeric(iris$Species)])

You can probably see how to further modify the code above to get any unique combination of colors.

How to create a video from images with FFmpeg?

-pattern_type glob

This great option makes it easier to select the images in many cases.

Slideshow video with one image per second

ffmpeg -framerate 1 -pattern_type glob -i '*.png' \
  -c:v libx264 -r 30 -pix_fmt yuv420p out.mp4

Add some music to it, cutoff when the presumably longer audio when the images end:

ffmpeg -framerate 1 -pattern_type glob -i '*.png' -i audio.ogg \
  -c:a copy -shortest -c:v libx264 -r 30 -pix_fmt yuv420p out.mp4

Here are two demos on YouTube:

Be a hippie and use the Theora patent-unencumbered video format:

ffmpeg -framerate 1 -pattern_type glob -i '*.png' -i audio.ogg \
  -c:a copy -shortest -c:v libtheora -r 30 -pix_fmt yuv420p out.ogg

Your images should of course be sorted alphabetically, typically as:

0001-first-thing.jpg
0002-second-thing.jpg
0003-and-third.jpg

and so on.

I would also first ensure that all images to be used have the same aspect ratio, possibly by cropping them with imagemagick or nomacs beforehand, so that ffmpeg will not have to make hard decisions. In particular, the width has to be divisible by 2, otherwise conversion fails with: "width not divisible by 2".

Normal speed video with one image per frame at 30 FPS

ffmpeg -framerate 30 -pattern_type glob -i '*.png' \
  -c:v libx264 -pix_fmt yuv420p out.mp4

Here's what it looks like:

GIF generated with: https://askubuntu.com/questions/648603/how-to-create-an-animated-gif-from-mp4-video-via-command-line/837574#837574

Add some audio to it:

ffmpeg -framerate 30 -pattern_type glob -i '*.png' \
  -i audio.ogg -c:a copy -shortest -c:v libx264 -pix_fmt yuv420p out.mp4

Result: https://www.youtube.com/watch?v=HG7c7lldhM4

These are the test media I've used:a

wget -O opengl-rotating-triangle.zip https://github.com/cirosantilli/media/blob/master/opengl-rotating-triangle.zip?raw=true
unzip opengl-rotating-triangle.zip
cd opengl-rotating-triangle
wget -O audio.ogg https://upload.wikimedia.org/wikipedia/commons/7/74/Alnitaque_%26_Moon_Shot_-_EURO_%28Extended_Mix%29.ogg

Images generated with: How to use GLUT/OpenGL to render to a file?

It is cool to observe how much the video compresses the image sequence way better than ZIP as it is able to compress across frames with specialized algorithms:

  • opengl-rotating-triangle.mp4: 340K
  • opengl-rotating-triangle.zip: 7.3M

Convert one music file to a video with a fixed image for YouTube upload

Answered at: https://superuser.com/questions/700419/how-to-convert-mp3-to-youtube-allowed-video-format/1472572#1472572

Full realistic slideshow case study setup step by step

There's a bit more to creating slideshows than running a single ffmpeg command, so here goes a more interesting detailed example inspired by this timeline.

Get the input media:

mkdir -p orig
cd orig
wget -O 1.png https://upload.wikimedia.org/wikipedia/commons/2/22/Australopithecus_afarensis.png
wget -O 2.jpg https://upload.wikimedia.org/wikipedia/commons/6/61/Homo_habilis-2.JPG
wget -O 3.jpg https://upload.wikimedia.org/wikipedia/commons/c/cb/Homo_erectus_new.JPG
wget -O 4.png https://upload.wikimedia.org/wikipedia/commons/1/1f/Homo_heidelbergensis_-_forensic_facial_reconstruction-crop.png
wget -O 5.jpg https://upload.wikimedia.org/wikipedia/commons/thumb/5/5a/Sabaa_Nissan_Militiaman.jpg/450px-Sabaa_Nissan_Militiaman.jpg
wget -O audio.ogg https://upload.wikimedia.org/wikipedia/commons/7/74/Alnitaque_%26_Moon_Shot_-_EURO_%28Extended_Mix%29.ogg
cd ..

# Convert all to PNG for consistency.
# https://unix.stackexchange.com/questions/29869/converting-multiple-image-files-from-jpeg-to-pdf-format
# Hardlink the ones that are already PNG.
mkdir -p png
mogrify -format png -path png orig/*.jpg
ln -P orig/*.png png

Now we have a quick look at all image sizes to decide on the final aspect ratio:

identify png/*

which outputs:

png/1.png PNG 557x495 557x495+0+0 8-bit sRGB 653KB 0.000u 0:00.000
png/2.png PNG 664x800 664x800+0+0 8-bit sRGB 853KB 0.000u 0:00.000
png/3.png PNG 544x680 544x680+0+0 8-bit sRGB 442KB 0.000u 0:00.000
png/4.png PNG 207x238 207x238+0+0 8-bit sRGB 76.8KB 0.000u 0:00.000
png/5.png PNG 450x600 450x600+0+0 8-bit sRGB 627KB 0.000u 0:00.000

so the classic 480p (640x480 == 4/3) aspect ratio seems appropriate.

Do one conversion with minimal resizing to make widths even (TODO automate for any width, here I just manually looked at identify output and reduced width and height by one):

mkdir -p raw
convert png/1.png -resize 556x494 raw/1.png
ln -P png/2.png png/3.png png/4.png png/5.png raw
ffmpeg -framerate 1 -pattern_type glob -i 'raw/*.png' -i orig/audio.ogg -c:v libx264 -c:a copy -shortest -r 30 -pix_fmt yuv420p raw.mp4

This produces terrible output, because as seen from:

ffprobe raw.mp4

ffmpeg just takes the size of the first image, 556x494, and then converts all others to that exact size, breaking their aspect ratio.

Now let's convert the images to the target 480p aspect ratio automatically by cropping as per ImageMagick: how to minimally crop an image to a certain aspect ratio?

mkdir -p auto
mogrify -path auto -geometry 640x480^ -gravity center -crop 640x480+0+0 png/*.png
ffmpeg -framerate 1 -pattern_type glob -i 'auto/*.png' -i orig/audio.ogg -c:v libx264 -c:a copy -shortest -r 30 -pix_fmt yuv420p auto.mp4

So now, the aspect ratio is good, but inevitably some cropping had to be done, which kind of cut up interesting parts of the images.

The other option is to pad with black background to have the same aspect ratio as shown at: Resize to fit in a box and set background to black on "empty" part

mkdir -p black
ffmpeg -framerate 1 -pattern_type glob -i 'black/*.png' -i orig/audio.ogg -c:v libx264 -c:a copy -shortest -r 30 -pix_fmt yuv420p black.mp4

Generally speaking though, you will ideally be able to select images with the same or similar aspect ratios to avoid those problems in the first place.

About the CLI options

Note however that despite the name, -glob this is not as general as shell Glob patters, e.g.: -i '*' fails: https://trac.ffmpeg.org/ticket/3620 (apparently because filetype is deduced from extension).

-r 30 makes the -framerate 1 video 30 FPS to overcome bugs in players like VLC for low framerates: VLC freezes for low 1 FPS video created from images with ffmpeg Therefore it repeats each frame 30 times to keep the desired 1 image per second effect.

Next steps

You will also want to:

TODO: learn to cut and concatenate multiple audio files into the video without intermediate files, I'm pretty sure it's possible:

Tested on

ffmpeg 3.4.4, vlc 3.0.3, Ubuntu 18.04.

Bibliography

top -c command in linux to filter processes listed based on processname

In htop, you can simply search with

/process-name

.NET 4.0 has a new GAC, why?

I also wanted to know why 2 GAC and found the following explanation by Mark Miller in the comments section of .NET 4.0 has 2 Global Assembly Cache (GAC):

Mark Miller said... June 28, 2010 12:13 PM

Thanks for the post. "Interference issues" was intentionally vague. At the time of writing, the issues were still being investigated, but it was clear there were several broken scenarios.

For instance, some applications use Assemby.LoadWithPartialName to load the highest version of an assembly. If the highest version was compiled with v4, then a v2 (3.0 or 3.5) app could not load it, and the app would crash, even if there were a version that would have worked. Originally, we partitioned the GAC under it's original location, but that caused some problems with windows upgrade scenarios. Both of these involved code that had already shipped, so we moved our (version-partitioned GAC to another place.

This shouldn't have any impact to most applications, and doesn't add any maintenance burden. Both locations should only be accessed or modified using the native GAC APIs, which deal with the partitioning as expected. The places where this does surface are through APIs that expose the paths of the GAC such as GetCachePath, or examining the path of mscorlib loaded into managed code.

It's worth noting that we modified GAC locations when we released v2 as well when we introduced architecture as part of the assembly identity. Those added GAC_MSIL, GAC_32, and GAC_64, although all still under %windir%\assembly. Unfortunately, that wasn't an option for this release.

Hope it helps future readers.

Handling a Menu Item Click Event - Android

This code is work for me

@Override
public boolean onOptionsItemSelected(MenuItem item) {

    int id = item.getItemId();

     if (id == R.id.action_settings) {
  // add your action here that you want
        return true;
    }

    else if (id==R.id.login)
     {
         // add your action here that you want
     }


    return super.onOptionsItemSelected(item);
}

How to remove specific object from ArrayList in Java?

This helped me:

        card temperaryCardFour = theDeck.get(theDeck.size() - 1);
        theDeck.remove(temperaryCardFour);    

instead of

theDeck.remove(numberNeededRemoved);

I got a removal conformation on the first snippet of code and an un removal conformation on the second.

Try switching your code with the first snippet I think that is your problem.

Nathan Nelson

How to use XMLReader in PHP?

Most of my XML parsing life is spent extracting nuggets of useful information out of truckloads of XML (Amazon MWS). As such, my answer assumes you want only specific information and you know where it is located.

I find the easiest way to use XMLReader is to know which tags I want the information out of and use them. If you know the structure of the XML and it has lots of unique tags, I find that using the first case is the easy. Cases 2 and 3 are just to show you how it can be done for more complex tags. This is extremely fast; I have a discussion of speed over on What is the fastest XML parser in PHP?

The most important thing to remember when doing tag-based parsing like this is to use if ($myXML->nodeType == XMLReader::ELEMENT) {... - which checks to be sure we're only dealing with opening nodes and not whitespace or closing nodes or whatever.

function parseMyXML ($xml) { //pass in an XML string
    $myXML = new XMLReader();
    $myXML->xml($xml);

    while ($myXML->read()) { //start reading.
        if ($myXML->nodeType == XMLReader::ELEMENT) { //only opening tags.
            $tag = $myXML->name; //make $tag contain the name of the tag
            switch ($tag) {
                case 'Tag1': //this tag contains no child elements, only the content we need. And it's unique.
                    $variable = $myXML->readInnerXML(); //now variable contains the contents of tag1
                    break;

                case 'Tag2': //this tag contains child elements, of which we only want one.
                    while($myXML->read()) { //so we tell it to keep reading
                        if ($myXML->nodeType == XMLReader::ELEMENT && $myXML->name === 'Amount') { // and when it finds the amount tag...
                            $variable2 = $myXML->readInnerXML(); //...put it in $variable2. 
                            break;
                        }
                    }
                    break;

                case 'Tag3': //tag3 also has children, which are not unique, but we need two of the children this time.
                    while($myXML->read()) {
                        if ($myXML->nodeType == XMLReader::ELEMENT && $myXML->name === 'Amount') {
                            $variable3 = $myXML->readInnerXML();
                            break;
                        } else if ($myXML->nodeType == XMLReader::ELEMENT && $myXML->name === 'Currency') {
                            $variable4 = $myXML->readInnerXML();
                            break;
                        }
                    }
                    break;

            }
        }
    }
$myXML->close();
}

Why am I getting error for apple-touch-icon-precomposed.png

I guess apple devices make those requests if the device owner adds the site to it. This is the equivalent of the favicon. To resolve, add 2 100×100 png files, save it as apple-touch-icon-precomposed.png and apple-touch-icon.png and upload it to the root directory of the server. After that, the error should be gone.

I noticed lots of requests for apple-touch-icon-precomposed.png and apple-touch-icon.png in the logs that tried to load the images from the root directory of the site. I first thought it was a misconfiguration of the mobile theme and plugin, but found out later that Apple devices make those requests if the device owner adds the site to it.

Source: Why Webmasters Should Analyze Their 404 Error Log (Mar 2012; by Martin Brinkmann)

How to assign a value to a TensorFlow variable?

First of all you can assign values to variables/constants just by feeding values into them the same way you do it with placeholders. So this is perfectly legal to do:

import tensorflow as tf
x = tf.Variable(0)
with tf.Session() as sess:
    sess.run(tf.global_variables_initializer())
    print sess.run(x, feed_dict={x: 3})

Regarding your confusion with the tf.assign() operator. In TF nothing is executed before you run it inside of the session. So you always have to do something like this: op_name = tf.some_function_that_create_op(params) and then inside of the session you run sess.run(op_name). Using assign as an example you will do something like this:

import tensorflow as tf
x = tf.Variable(0)
y = tf.assign(x, 1)
with tf.Session() as sess:
    sess.run(tf.global_variables_initializer())
    print sess.run(x)
    print sess.run(y)
    print sess.run(x)

php & mysql query not echoing in html with tags?

<td class="first"> <?php echo $proxy ?> </td> is inside a literal string that you are echoing. End the string, or concatenate it correctly:

<td class="first">' . $proxy . '</td>

how much memory can be accessed by a 32 bit machine?

Yes, on a 32bit machine the maximum amount of memory usable is around 4GB. Actually, depending on the OS it might be less due to parts of the address space being reserved: On Windows you can only use 3.5GB for example.

On 64bit you can indeed address 2^64 bytes of memory. Not that you'll ever have those - but then again, a long time ago the same thing was said about ever needing more than 640kb of memory...

Check if a string is html or not

Method #1. Here is the simple function to test if the string contains HTML data:

function isHTML(str) {
  var a = document.createElement('div');
  a.innerHTML = str;

  for (var c = a.childNodes, i = c.length; i--; ) {
    if (c[i].nodeType == 1) return true; 
  }

  return false;
}

The idea is to allow browser DOM parser to decide if provided string looks like an HTML or not. As you can see it simply checks for ELEMENT_NODE (nodeType of 1).

I made a couple of tests and looks like it works:

isHTML('<a>this is a string</a>') // true
isHTML('this is a string')        // false
isHTML('this is a <b>string</b>') // true

This solution will properly detect HTML string, however it has side effect that img/vide/etc. tags will start downloading resource once parsed in innerHTML.

Method #2. Another method uses DOMParser and doesn't have loading resources side effects:

function isHTML(str) {
  var doc = new DOMParser().parseFromString(str, "text/html");
  return Array.from(doc.body.childNodes).some(node => node.nodeType === 1);
}

Notes:
1. Array.from is ES2015 method, can be replaced with [].slice.call(doc.body.childNodes).
2. Arrow function in some call can be replaced with usual anonymous function.

How to check if my string is equal to null?

if(str.isEmpty() || str==null){ do whatever you want }

Best way to convert an ArrayList to a string

Android has a TextUtil class you can use http://developer.android.com/reference/android/text/TextUtils.html

String implode = TextUtils.join("\t", list);

How to compile a static library in Linux?

Here a full makefile example:

makefile

TARGET = prog

$(TARGET): main.o lib.a
    gcc $^ -o $@

main.o: main.c
    gcc -c $< -o $@

lib.a: lib1.o lib2.o
    ar rcs $@ $^

lib1.o: lib1.c lib1.h
    gcc -c -o $@ $<

lib2.o: lib2.c lib2.h
    gcc -c -o $@ $<

clean:
    rm -f *.o *.a $(TARGET)

explaining the makefile:

  • target: prerequisites - the rule head
  • $@ - means the target
  • $^ - means all prerequisites
  • $< - means just the first prerequisite
  • ar - a Linux tool to create, modify, and extract from archives see the man pages for further information. The options in this case mean:
    • r - replace files existing inside the archive
    • c - create a archive if not already existent
    • s - create an object-file index into the archive

To conclude: The static library under Linux is nothing more than a archive of object files.

main.c using the lib

#include <stdio.h>

#include "lib.h"

int main ( void )
{
    fun1(10);
    fun2(10);
    return 0;
}

lib.h the libs main header

#ifndef LIB_H_INCLUDED
#define LIB_H_INCLUDED

#include "lib1.h"
#include "lib2.h"

#endif

lib1.c first lib source

#include "lib1.h"

#include <stdio.h>

void fun1 ( int x )
{
    printf("%i\n",x);
}

lib1.h the corresponding header

#ifndef LIB1_H_INCLUDED
#define LIB1_H_INCLUDED

#ifdef __cplusplus
   extern “C” {
#endif

void fun1 ( int x );

#ifdef __cplusplus
   }
#endif

#endif /* LIB1_H_INCLUDED */

lib2.c second lib source

#include "lib2.h"

#include <stdio.h>

void fun2 ( int x )
{
    printf("%i\n",2*x);
}

lib2.h the corresponding header

#ifndef LIB2_H_INCLUDED
#define LIB2_H_INCLUDED

#ifdef __cplusplus
   extern “C” {
#endif

void fun2 ( int x );

#ifdef __cplusplus
   }
#endif

#endif /* LIB2_H_INCLUDED */

whitespaces in the path of windows filepath

There is no problem with whitespaces in the path since you're not using the "shell" to open the file. Here is a session from the windows console to prove the point. You're doing something else wrong

Python 2.7.2 (default, Jun 12 2011, 14:24:46) [MSC v.1500 64 bit (AMD64)] on wi
32
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>>
>>> os.makedirs("C:/ABC/SEM 2/testfiles")
>>> open("C:/ABC/SEM 2/testfiles/all.txt","w")
<open file 'C:/ABC/SEM 2/testfiles/all.txt', mode 'w' at 0x0000000001D95420>
>>> exit()

C:\Users\Gnibbler>dir "C:\ABC\SEM 2\testfiles"
 Volume in drive C has no label.
 Volume Serial Number is 46A0-BB64

 Directory of c:\ABC\SEM 2\testfiles

13/02/2013  10:20 PM    <DIR>          .
13/02/2013  10:20 PM    <DIR>          ..
13/02/2013  10:20 PM                 0 all.txt
               1 File(s)              0 bytes
               2 Dir(s)  78,929,309,696 bytes free

C:\Users\Gnibbler>

Increment a database field by 1

If you can safely make (firstName, lastName) the PRIMARY KEY or at least put a UNIQUE key on them, then you could do this:

INSERT INTO logins (firstName, lastName, logins) VALUES ('Steve', 'Smith', 1)
ON DUPLICATE KEY UPDATE logins = logins + 1;

If you can't do that, then you'd have to fetch whatever that primary key is first, so I don't think you could achieve what you want in one query.

Converting a String array into an int Array in java

public static int[] strArrayToIntArray(String[] a){
    int[] b = new int[a.length];
    for (int i = 0; i < a.length; i++) {
        b[i] = Integer.parseInt(a[i]);
    }

    return b;
}

This is a simple function, that should help you. You can use him like this:

int[] arr = strArrayToIntArray(/*YOUR STR ARRAY*/);

What is the difference between Multiple R-squared and Adjusted R-squared in a single-variate least squares regression?

The R-squared is not dependent on the number of variables in the model. The adjusted R-squared is.

The adjusted R-squared adds a penalty for adding variables to the model that are uncorrelated with the variable your trying to explain. You can use it to test if a variable is relevant to the thing your trying to explain.

Adjusted R-squared is R-squared with some divisions added to make it dependent on the number of variables in the model.

Print newline in PHP in single quotes

No, because single-quotes even inhibit hex code replacement.

echo 'Hello, world!' . "\xA";

How to obfuscate Python code effectively?

Opy

https://github.com/QQuick/Opy

Opy will obfuscate your extensive, real world, multi module Python source code for free! And YOU choose per project what to obfuscate and what not, by editing the config file:

You can recursively exclude all identifiers of certain modules from obfuscation.
You can exclude human readable configuration files containing Python code.
You can use getattr, setattr, exec and eval by excluding the identifiers they use.
You can even obfuscate module file names and string literals.
You can run your obfuscated code from any platform.

Unlike some of the other options posted, this works for both Python 2 and 3! It is also free / opensource, and it is not an online only tool (unless you pay) like some of the others out there.

I am admittedly still evaluating this myself, but all of initial tests of it worked perfectly. It appears this is exactly what I was looking for!

The official version runs as a standalone utility, with the original intended design being that you drop a script into the root of the directory you want to obfuscate, along with a config file to define the details/options you want to employ. I wasn't in love with that plan, so I added a fork from project, allowing you to import and utilize the tool from a library instead. That way, you can roll this directly into a more encompassing packaging script. (You could of course wrap multiple py scripts in bash/batch, but I think a pure python solution is ideal). I requested my fork be merged into the original work, but in case that never happens, here's the url to my revised version:

https://github.com/BuvinJT/Opy

selenium - chromedriver executable needs to be in PATH

Try this :

pip install webdriver-manager
from selenium import webdriver
from webdriver_manager.chrome import ChromeDriverManager

driver = webdriver.Chrome(ChromeDriverManager().install())

Telnet is not recognized as internal or external command

If your Windows 7 machine is a member of an AD, or if you have UAC enabled, or if security policies are in effect, telnet more often than not must be run as an admin. The easiest way to do this is as follows

  1. Create a shortcut that calls cmd.exe

  2. Go to the shortcut's properties

  3. Click on the Advanced button

  4. Check the "Run as an administrator" checkbox

    After these steps you're all set and telnet should work now.

Converting string to integer

The function you need is CInt.

ie CInt(PrinterLabel)

See Type Conversion Functions (Visual Basic) on MSDN

Edit: Be aware that CInt and its relatives behave differently in VB.net and VBScript. For example, in VB.net, CInt casts to a 32-bit integer, but in VBScript, CInt casts to a 16-bit integer. Be on the lookout for potential overflows!

Resolving javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed Error?

For MacOS X below is the exact command worked for me where I had to try with double hypen in 'importcert' option which worked :

sudo keytool -–importcert -file /PathTo/YourCertFileDownloadedFromBrowserLockIcon.crt -keystore /Library/Java/JavaVirtualMachines/jdk1.8.0_191.jdk/Contents/Home/jre/lib/security/cacerts -alias "Cert" -storepass changeit

Edit a text file on the console using Powershell

install vim from online, and then you can just do: vim "filename" to edit that file

Console output in a Qt GUI app?

Make sure Qt5Core.dll is in the same directory with your application executable.

I had a similar issue in Qt5 with a console application: if I start the application from Qt Creator, the output text is visible, if I open cmd.exe and start the same application there, no output is visible. Very strange!

I solved it by copying Qt5Core.dll to the directory with the application executable.

Here is my tiny console application:

#include <QCoreApplication>
#include <QDebug>

int main(int argc, char *argv[])
{
    int x=343;
    QString str("Hello World");
    qDebug()<< str << x<<"lalalaa";

    QTextStream out(stdout);
    out << "aldfjals alsdfajs...";
}

Connection refused to MongoDB errno 111

Even though the port is open, MongoDB is currently only listening on the local address 127.0.0.1. To allow remote connections, add your server’s publicly-routable IP address to the mongod.conf file.

Open the MongoDB configuration file in your editor:

sudo nano /etc/mongodb.conf

Add your server’s IP address to the bindIP value:

...
logappend=true

bind_ip = 127.0.0.1,your_server_ip
#port = 27017

...

Note that now everybody who has the username and password can login to your DB and you want to avoid this by restrict the connection only for specific IP's. This can be done using Firewall (read about UFW service at Google). But in short this should be something like this:

sudo ufw allow from YOUR_IP to any port 27017

How do I authenticate a WebClient request?

Public Function getWeb(ByRef sURL As String) As String
    Dim myWebClient As New System.Net.WebClient()

    Try
        Dim myCredentialCache As New System.Net.CredentialCache()
        Dim myURI As New Uri(sURL)
        myCredentialCache.Add(myURI, "ntlm", System.Net.CredentialCache.DefaultNetworkCredentials)
        myWebClient.Encoding = System.Text.Encoding.UTF8
        myWebClient.Credentials = myCredentialCache
        Return myWebClient.DownloadString(myURI)
    Catch ex As Exception
        Return "Exception " & ex.ToString()
    End Try
End Function

How to create an infinite loop in Windows batch file?

read help GOTO

and try

:again
do it
goto again

How to insert the current timestamp into MySQL database using a PHP insert query

What error message are you getting?

I'd guess your actual error is because your php variable isn't wrapped in quotes. Try this

$update_query = "UPDATE db.tablename SET insert_time=now() WHERE username='" .$somename . "'"; 

How to deal with SQL column names that look like SQL keywords?

If it had been in PostgreSQL, use double quotes around the name, like:

select "from" from "table";

Note: Internally PostgreSQL automatically converts all unquoted commands and parameters to lower case. That have the effect that commands and identifiers aren't case sensitive. sEleCt * from tAblE; is interpreted as select * from table;. However, parameters inside double quotes are used as is, and therefore ARE case sensitive: select * from "table"; and select * from "Table"; gets the result from two different tables.

tmux set -g mouse-mode on doesn't work

As @Graham42 noted, mouse option has changed in version 2.1. Scrolling now requires for you to enter copy mode first. To enable scrolling almost identical to how it was before 2.1 add following to your .tmux.conf.

set-option -g mouse on

# make scrolling with wheels work
bind -n WheelUpPane if-shell -F -t = "#{mouse_any_flag}" "send-keys -M" "if -Ft= '#{pane_in_mode}' 'send-keys -M' 'select-pane -t=; copy-mode -e; send-keys -M'"
bind -n WheelDownPane select-pane -t= \; send-keys -M

This will enable scrolling on hover over a pane and you will be able to scroll that pane line by line.

Source: https://groups.google.com/d/msg/tmux-users/TRwPgEOVqho/Ck_oth_SDgAJ

Objective-C and Swift URL encoding

Swift iOS:

Just For Information : I have used this:

extension String {

    func urlEncode() -> CFString {
        return CFURLCreateStringByAddingPercentEscapes(
            nil,
            self,
            nil,
            "!*'();:@&=+$,/?%#[]",
            CFStringBuiltInEncodings.UTF8.rawValue
        )
    }

}// end extension String

What is the most robust way to force a UIView to redraw?

The money-back guaranteed, reinforced-concrete-solid way to force a view to draw synchronously (before returning to the calling code) is to configure the CALayer's interactions with your UIView subclass.

In your UIView subclass, create a displayNow() method that tells the layer to “set course for display” then to “make it so”:

Swift

/// Redraws the view's contents immediately.
/// Serves the same purpose as the display method in GLKView.
public func displayNow()
{
    let layer = self.layer
    layer.setNeedsDisplay()
    layer.displayIfNeeded()
}

Objective-C

/// Redraws the view's contents immediately.
/// Serves the same purpose as the display method in GLKView.
- (void)displayNow
{
    CALayer *layer = self.layer;
    [layer setNeedsDisplay];
    [layer displayIfNeeded];
}

Also implement a draw(_: CALayer, in: CGContext) method that'll call your private/internal drawing method (which works since every UIView is a CALayerDelegate):

Swift

/// Called by our CALayer when it wants us to draw
///     (in compliance with the CALayerDelegate protocol).
override func draw(_ layer: CALayer, in context: CGContext)
{
    UIGraphicsPushContext(context)
    internalDraw(self.bounds)
    UIGraphicsPopContext()
}

Objective-C

/// Called by our CALayer when it wants us to draw
///     (in compliance with the CALayerDelegate protocol).
- (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)context
{
    UIGraphicsPushContext(context);
    [self internalDrawWithRect:self.bounds];
    UIGraphicsPopContext();
}

And create your custom internalDraw(_: CGRect) method, along with fail-safe draw(_: CGRect):

Swift

/// Internal drawing method; naming's up to you.
func internalDraw(_ rect: CGRect)
{
    // @FILLIN: Custom drawing code goes here.
    //  (Use `UIGraphicsGetCurrentContext()` where necessary.)
}

/// For compatibility, if something besides our display method asks for draw.
override func draw(_ rect: CGRect) {
    internalDraw(rect)
}

Objective-C

/// Internal drawing method; naming's up to you.
- (void)internalDrawWithRect:(CGRect)rect
{
    // @FILLIN: Custom drawing code goes here.
    //  (Use `UIGraphicsGetCurrentContext()` where necessary.)
}

/// For compatibility, if something besides our display method asks for draw.
- (void)drawRect:(CGRect)rect {
    [self internalDrawWithRect:rect];
}

And now just call myView.displayNow() whenever you really-really need it to draw (such as from a CADisplayLink callback).  Our displayNow() method will tell the CALayer to displayIfNeeded(), which will synchronously call back into our draw(_:,in:) and do the drawing in internalDraw(_:), updating the visual with what's drawn into the context before moving on.


This approach is similar to @RobNapier's above, but has the advantage of calling displayIfNeeded() in addition to setNeedsDisplay(), which makes it synchronous.

This is possible because CALayers expose more drawing functionality than UIViews do— layers are lower-level than views and designed explicitly for the purpose of highly-configurable drawing within the layout, and (like many things in Cocoa) are designed to be used flexibly (as a parent class, or as a delegator, or as a bridge to other drawing systems, or just on their own). Proper usage of the CALayerDelegate protocol makes all this possible.

More information about the configurability of CALayers can be found in the Setting Up Layer Objects section of the Core Animation Programming Guide.

java.lang.ClassNotFoundException: org.springframework.web.context.ContextLoaderListener

Solution for Eclipse Luna:

  1. Right Click on maven web project
  2. Click 'Properties'menu
  3. Select 'Deployment Assembly' in left side of the popped window
  4. Click 'Add...' Button in right side of the popped up window
  5. Now appear one more popup window(New Assembly Directivies)
  6. Click 'Java Build path entries'
  7. Click 'Next' Button
  8. Click 'Finish' Button, now atomatically close New Assemby Directivies popup window
  9. Now click 'Apply' Button and Ok Button
  10. Run your webapplication

Why use double indirection? or Why use pointers to pointers?

Strings are a great example of uses of double pointers. The string itself is a pointer, so any time you need to point to a string, you'll need a double pointer.

java.lang.NoClassDefFoundError: com/sun/mail/util/MailLogger for JUnit test case for Java mail

I use the following maven dependencies to get java mail working. The first one includes the javax.mail API (with no implementation) and the second one is the SUN implementation of the javax.mail API.

<dependency>
    <groupId>javax.mail</groupId>
    <artifactId>javax.mail-api</artifactId>
    <version>1.5.5</version>
</dependency>
<dependency>
    <groupId>com.sun.mail</groupId>
    <artifactId>javax.mail</artifactId>
    <version>1.5.5</version>
</dependency>

OpenCV C++/Obj-C: Detecting a sheet of paper / Square Detection

Detecting sheet of paper is kinda old school. If you want to tackle skew detection then it is better if you straightaway aim for text line detection. With this you will get the extremas left, right, top and bottom. Discard any graphics in the image if you dont want and then do some statistics on the text line segments to find the most occurring angle range or rather angle. This is how you will narrow down to a good skew angle. Now after this you put these parameters the skew angle and the extremas to deskew and chop the image to what is required.

As for the current image requirement, it is better if you try CV_RETR_EXTERNAL instead of CV_RETR_LIST.

Another method of detecting edges is to train a random forests classifier on the paper edges and then use the classifier to get the edge Map. This is by far a robust method but requires training and time.

Random forests will work with low contrast difference scenarios for example white paper on roughly white background.

How to create a generic array?

checked :

public Constructor(Class<E> c, int length) {

    elements = (E[]) Array.newInstance(c, length);
}

or unchecked :

public Constructor(int s) {
    elements = new Object[s];
}

Override element.style using CSS

you can override the style on your css by referencing the offending property of the element style. On my case these two codes are set as 15px and is causing my background image to go black. So, i override them with 0px and placed the !important so it will be priority

.content {
    border-bottom-left-radius: 0px !important;
     border-bottom-right-radius: 0px !important;
}

Convert a String to a byte array and then back to the original String

import java.io.FileInputStream; import java.io.ByteArrayOutputStream;

public class FileHashStream { // write a new method that will provide a new Byte array, and where this generally reads from an input stream

public static byte[] read(InputStream is) throws Exception
{
    String path = /* type in the absolute path for the 'commons-codec-1.10-bin.zip' */;

    // must need a Byte buffer

    byte[] buf = new byte[1024 * 16]

    // we will use 16 kilobytes

    int len = 0;

    // we need a new input stream

    FileInputStream is = new FileInputStream(path);

    // use the buffer to update our "MessageDigest" instance

    while(true)
    {
        len = is.read(buf);
        if(len < 0) break;
        md.update(buf, 0, len);
    }

    // close the input stream

    is.close();

    // call the "digest" method for obtaining the final hash-result

    byte[] ret = md.digest();

    System.out.println("Length of Hash: " + ret.length);

    for(byte b : ret)
    {
        System.out.println(b + ", ");
    }

    String compare = "49276d206b696c6c696e6720796f757220627261696e206c696b65206120706f69736f6e6f7573206d757368726f6f6d";

    String verification = Hex.encodeHexString(ret);

    System.out.println();

    System.out.println("===")

    System.out.println(verification);

    System.out.println("Equals? " + verification.equals(compare));

}

}

Is a LINQ statement faster than a 'foreach' loop?

LINQ-to-Objects generally is going to add some marginal overheads (multiple iterators, etc). It still has to do the loops, and has delegate invokes, and will generally have to do some extra dereferencing to get at captured variables etc. In most code this will be virtually undetectable, and more than afforded by the simpler to understand code.

With other LINQ providers like LINQ-to-SQL, then since the query can filter at the server it should be much better than a flat foreach, but most likely you wouldn't have done a blanket "select * from foo" anyway, so that isn't necessarily a fair comparison.

Re PLINQ; parallelism may reduce the elapsed time, but the total CPU time will usually increase a little due to the overheads of thread management etc.

How to check if text fields are empty on form submit using jQuery?

A simple solution would be something like this

$( "form" ).on( "submit", function() { 

   var has_empty = false;

   $(this).find( 'input[type!="hidden"]' ).each(function () {

      if ( ! $(this).val() ) { has_empty = true; return false; }
   });

   if ( has_empty ) { return false; }
});

Note: The jQuery.on() method is only available in jQuery version 1.7+, but it is now the preferred method of attaching event handlers.

This code loops through all of the inputs in the form and prevents form submission by returning false if any of them have no value. Note that it doesn't display any kind of message to the user about why the form failed to submit (I would strongly recommend adding one).

Or, you could look at the jQuery validate plugin. It does this and a lot more.

NB: This type of technique should always be used in conjunction with server side validation.

How to sum a variable by group

The answer provided by rcs works and is simple. However, if you are handling larger datasets and need a performance boost there is a faster alternative:

library(data.table)
data = data.table(Category=c("First","First","First","Second","Third", "Third", "Second"), 
                  Frequency=c(10,15,5,2,14,20,3))
data[, sum(Frequency), by = Category]
#    Category V1
# 1:    First 30
# 2:   Second  5
# 3:    Third 34
system.time(data[, sum(Frequency), by = Category] )
# user    system   elapsed 
# 0.008     0.001     0.009 

Let's compare that to the same thing using data.frame and the above above:

data = data.frame(Category=c("First","First","First","Second","Third", "Third", "Second"),
                  Frequency=c(10,15,5,2,14,20,3))
system.time(aggregate(data$Frequency, by=list(Category=data$Category), FUN=sum))
# user    system   elapsed 
# 0.008     0.000     0.015 

And if you want to keep the column this is the syntax:

data[,list(Frequency=sum(Frequency)),by=Category]
#    Category Frequency
# 1:    First        30
# 2:   Second         5
# 3:    Third        34

The difference will become more noticeable with larger datasets, as the code below demonstrates:

data = data.table(Category=rep(c("First", "Second", "Third"), 100000),
                  Frequency=rnorm(100000))
system.time( data[,sum(Frequency),by=Category] )
# user    system   elapsed 
# 0.055     0.004     0.059 
data = data.frame(Category=rep(c("First", "Second", "Third"), 100000), 
                  Frequency=rnorm(100000))
system.time( aggregate(data$Frequency, by=list(Category=data$Category), FUN=sum) )
# user    system   elapsed 
# 0.287     0.010     0.296 

For multiple aggregations, you can combine lapply and .SD as follows

data[, lapply(.SD, sum), by = Category]
#    Category Frequency
# 1:    First        30
# 2:   Second         5
# 3:    Third        34

ArrayIndexOutOfBoundsException when using the ArrayList's iterator

Am I doing that right, as far as iterating through the Arraylist goes?

No: by calling iterator twice in each iteration, you're getting new iterators all the time.

The easiest way to write this loop is using the for-each construct:

for (String s : arrayList)
    if (s.equals(value))
        // ...

As for

java.lang.ArrayIndexOutOfBoundsException: -1

You just tried to get element number -1 from an array. Counting starts at zero.

make iframe height dynamic based on content inside- JQUERY/Javascript

Add this to the iframe, this worked for me:

onload="this.height=this.contentWindow.document.body.scrollHeight;"

And if you use jQuery try this code:

onload="$(this).height($(this.contentWindow.document.body).find(\'div\').first().height());"

How to log out user from web site using BASIC authentication?

add this to your application :

@app.route('/logout')
def logout():
    return ('Logout', 401, {'WWW-Authenticate': 'Basic realm="Login required"'})

Android Intent Cannot resolve constructor

Same Error was coming with my code in Activity but not in Fragment. Showing constructor error for different line like new Intent( From.this, To.class) and new ArrayList<> etc.

Fixed using closing Android Studio and moving the repository to other location and opening the the project once again. Fixed the problem.

Seems like Android Studio building problem.

Disable Buttons in jQuery Mobile

For link button,

Calling .button('enable') method only gives effect, but functionally don't.

But I have a trick. We could use HTML5 data- attribute to save/swap value of href and onclick.

see:

http://jsbin.com/ukewu3/74/

source code mode:

http://jsbin.com/ukewu3/74/edit

How to clone object in C++ ? Or Is there another solution?

In C++ copying the object means cloning. There is no any special cloning in the language.

As the standard suggests, after copying you should have 2 identical copies of the same object.

There are 2 types of copying: copy constructor when you create object on a non initialized space and copy operator where you need to release the old state of the object (that is expected to be valid) before setting the new state.

MS SQL Date Only Without Time

DATEADD(d, 0, DATEDIFF(d, 0, [tstamp]))

Edit: While this will remove the time portion of your datetime, it will also make the condition non SARGable. If that's important for this query, an indexed view or a between clause is more appropriate.

SQL: how to select a single id ("row") that meets multiple criteria from a single column

Users who have one of the 3 countries

SELECT DISTINCT user_id
FROM table
WHERE ancestry IN('England','France','Germany')

Users who have all 3 countries

SELECT DISTINCT A.userID
FROM table A
   INNER JOIN table B on A.user_id = B.user_id
   INNER JOIN table C on A.user_id = C.user_id
WHERE A.ancestry = 'England'
   AND B.ancestry = 'Germany'
   AND C.ancestry = 'France'

Show div on scrollDown after 800px

You've got a few things going on there. One, why a class? Do you actually have multiple of these on the page? The CSS suggests you can't. If not you should use an ID - it's faster to select both in CSS and jQuery:

<div id=bottomMenu>You read it all.</div>

Second you've got a few crazy things going on in that CSS - in particular the z-index is supposed to just be a number, not measured in pixels. It specifies what layer this tag is on, where each higher number is closer to the user (or put another way, on top of/occluding tags with lower z-indexes).

The animation you're trying to do is basically .fadeIn(), so just set the div to display: none; initially and use .fadeIn() to animate it:

$('#bottomMenu').fadeIn(2000);

.fadeIn() works by first doing display: (whatever the proper display property is for the tag), opacity: 0, then gradually ratcheting up the opacity.

Full working example:

http://jsfiddle.net/b9chris/sMyfT/

CSS:

#bottomMenu {
    display: none;
    position: fixed;
    left: 0; bottom: 0;
    width: 100%; height: 60px;
    border-top: 1px solid #000;
    background: #fff;
    z-index: 1;
}

JS:

var $win = $(window);

function checkScroll() {
    if ($win.scrollTop() > 100) {
        $win.off('scroll', checkScroll);
        $('#bottomMenu').fadeIn(2000);
    }
}

$win.scroll(checkScroll);

How can I change image tintColor in iOS and WatchKit

For swift 3 purposes

theImageView.image = theImageView.image!.withRenderingMode(.alwaysTemplate)
theImageView.tintColor = UIColor.red

How to create PDF files in Python

I use rst2pdf to create a pdf file, since I am more familiar with RST than with HTML. It supports embedding almost any kind of raster or vector images.

It requires reportlab, but I found reportlab is not so straight forward to use (at least for me).

Bound method error

You have an instance method called num_words, but you also have a variable called num_words. They have the same name. When you run num_words(), the function replaces itself with its own output, which probably isn't what you want to do. Consider returning your values.

To fix your problem, change def num_words to something like def get_num_words and your code should work fine. Also, change print test.sort_word_list to print test.sorted_word_list.

oracle diff: how to compare two tables?

For this kind of question I think you have to be very specific about what you are looking for, as there are many ways of interpreting it and many different approaches. Some approaches are going to be too big a hammer if your question does not warrant it.

At the simplest level, there is "Is the table data exactly the same or not?", which you might attempt to answer with a simple count comparison before moving on to anything more complex.

At the other end of the scale there is "show me the rows from each table for which there is not an equivalent row in the other table" or "show me where rows have the same identifying key but different data values".

If you actually want to sync Table A with Table B then that might be relatively straightforward, using a MERGE command.

how to prevent "directory already exists error" in a makefile when using mkdir

A little simpler than Lars' answer:

something_needs_directory_xxx : xxx/..

and generic rule:

%/.. : ;@mkdir -p $(@D)

No touch-files to clean up or make .PRECIOUS :-)

If you want to see another little generic gmake trick, or if you're interested in non-recursive make with minimal scaffolding, you might care to check out Two more cheap gmake tricks and the other make-related posts in that blog.

How can I stream webcam video with C#?

If you want a "capture/streamer in a box" component, there are several out there as others have mentioned.

If you want to get down to the low-level control over it all, you'll need to use DirectShow as thealliedhacker points out. The best way to use DirectShow in C# is through the DirectShow.Net library - it wraps all of the DirectShow COM APIs and includes many useful shortcut functions for you.

In addition to capturing and streaming, you can also do recording, audio and video format conversions, audio and video live filters, and a whole lot of stuff.

Microsoft claims DirectShow is going away, but they have yet to release a new library or API that does everything that DirectShow provides. I suspect many of the latest things they have released are still DirectShow under the hood. Because of its status at Microsoft, there aren't a whole lot of books or references on it other than MSDN and what you can find on forums. Last year when we started a project using it, the best book on the subject - Programming Microsoft DirectShow - was out of print and going for around $350 for a used copy!

Understanding the results of Execute Explain Plan in Oracle SQL Developer

The CBO builds a decision tree, estimating the costs of each possible execution path available per query. The costs are set by the CPU_cost or I/O_cost parameter set on the instance. And the CBO estimates the costs, as best it can with the existing statistics of the tables and indexes that the query will use. You should not tune your query based on cost alone. Cost allows you to understand WHY the optimizer is doing what it does. Without cost you could figure out why the optimizer chose the plan it did. Lower cost does not mean a faster query. There are cases where this is true and there will be cases where this is wrong. Cost is based on your table stats and if they are wrong the cost is going to be wrong.

When tuning your query, you should take a look at the cardinality and the number of rows of each step. Do they make sense? Is the cardinality the optimizer is assuming correct? Is the rows being return reasonable. If the information present is wrong then its very likely the optimizer doesn't have the proper information it needs to make the right decision. This could be due to stale or missing statistics on the table and index as well as cpu-stats. Its best to have stats updated when tuning a query to get the most out of the optimizer. Knowing your schema is also of great help when tuning. Knowing when the optimizer chose a really bad decision and pointing it in the correct path with a small hint can save a load of time.

What is the difference between concurrent programming and parallel programming?

Different people talk about different kinds of concurrency and parallelism in many different specific cases, so some abstractions to cover their common nature are needed.

The basic abstraction is done in computer science, where both concurrency and parallelism are attributed to the properties of programs. Here, programs are formalized descriptions of computing. Such programs need not to be in any particular language or encoding, which is implementation-specific. The existence of API/ABI/ISA/OS is irrelevant to such level of abstraction. Surely one will need more detailed implementation-specific knowledge (like threading model) to do concrete programming works, the spirit behind the basic abstraction is not changed.

A second important fact is, as general properties, concurrency and parallelism can coexist in many different abstractions.

For the general distinction, see the relevant answer for the basic view of concurrency v. parallelism. (There are also some links containing some additional sources.)

Concurrent programming and parallel programming are techniques to implement such general properties with some systems which expose programmability. The systems are usually programming languages and their implementations.

A programming language may expose the intended properties by built-in semantic rules. In most cases, such rules specify the evaluations of specific language structures (e.g. expressions) making the computation involved effectively concurrent or parallel. (More specifically, the computational effects implied by the evaluations can perfectly reflect these properties.) However, concurrent/parallel language semantics are essentially complex and they are not necessary to practical works (to implement efficient concurrent/parallel algorithms as the solutions of realistic problems). So, most traditional languages take a more conservative and simpler approach: assuming the semantics of evaluation totally sequential and serial, then providing optional primitives to allow some of the computations being concurrent and parallel. These primitives can be keywords or procedural constructs ("functions") supported by the language. They are implemented based on the interaction with hosted environments (OS, or "bare metal" hardware interface), usually opaque (not able to be derived using the language portably) to the language. Thus, in this particular kind of high-level abstractions seen by the programmers, nothing is concurrent/parallel besides these "magic" primitives and programs relying on these primitives; the programmers can then enjoy less error-prone experience of programming when concurrency/parallelism properties are not so interested.

Although primitives abstract the complex away in the most high-level abstractions, the implementations still have the extra complexity not exposed by the language feature. So, some mid-level abstractions are needed. One typical example is threading. Threading allows one or more thread of execution (or simply thread; sometimes it is also called a process, which is not necessarily the concept of a task scheduled in an OS) supported by the language implementation (the runtime). Threads are usually preemptively scheduled by the runtime, so a thread needs to know nothing about other threads. Thus, threads are natural to implement parallelism as long as they share nothing (the critical resources): just decompose computations in different threads, once the underlying implementation allows the overlapping of the computation resources during the execution, it works. Threads are also subject to concurrent accesses of shared resources: just access resources in any order meets the minimal constraints required by the algorithm, and the implementation will eventually determine when to access. In such cases, some synchronization operations may be necessary. Some languages treat threading and synchronization operations as parts of the high-level abstraction and expose them as primitives, while some other languages encourage only relatively more high-level primitives (like futures/promises) instead.

Under the level of language-specific threads, there come multitasking of the underlying hosting environment (typically, an OS). OS-level preemptive multitasking are used to implement (preemptive) multithreading. In some environments like Windows NT, the basic scheduling units (the tasks) are also "threads". To differentiate them with userspace implementation of threads mentioned above, they are called kernel threads, where "kernel" means the kernel of the OS (however, strictly speaking, this is not quite true for Windows NT; the "real" kernel is the NT executive). Kernel threads are not always 1:1 mapped to the userspace threads, although 1:1 mapping often reduces most overhead of mapping. Since kernel threads are heavyweight (involving system calls) to create/destroy/communicate, there are non 1:1 green threads in the userspace to overcome the overhead problems at the cost of the mapping overhead. The choice of mapping depending on the programming paradigm expected in the high-level abstraction. For example, when a huge number of userspace threads expected being concurrently executed (like Erlang), 1:1 mapping is never feasible.

The underlying of OS multitasking is ISA-level multitasking provided by the logical core of the processor. This is usually the most low-level public interface for programmers. Beneath this level, there may exist SMT. This is a form of more low-level multithreading implemented by the hardware, but arguably, still somewhat programmable - though it is usually only accessible by the processor manufacturer. Note the hardware design is apparently reflecting parallelism, but there is also concurrent scheduling mechanism to make the internal hardware resources being efficiently used.

In each level of "threading" mentioned above, both concurrency and parallelism are involved. Although the programming interfaces vary dramatically, all of them are subject to the properties revealed by the basic abstraction at the very beginning.

How do I enable C++11 in gcc?

If you are using sublime then this code may work if you add it in build as code for building system. You can use this link for more information.

{
    "shell_cmd": "g++ \"${file}\" -std=c++1y -o \"${file_path}/${file_base_name}\"",
    "file_regex": "^(..[^:]*):([0-9]+):?([0-9]+)?:? (.*)$",
    "working_dir": "${file_path}",
    "selector": "source.c, source.c++",

    "variants":
    [
        {
            "name": "Run",
            "shell_cmd": "g++ \"${file}\" -std=c++1y -o \"${file_path}/${file_base_name}\" && \"${file_path}/${file_base_name}\""
        }
    ]
}

What is a wrapper class?

In general, a wrapper class is any class which "wraps" or "encapsulates" the functionality of another class or component. These are useful by providing a level of abstraction from the implementation of the underlying class or component; for example, wrapper classes that wrap COM components can manage the process of invoking the COM component without bothering the calling code with it. They can also simplify the use of the underlying object by reducing the number interface points involved; frequently, this makes for more secure use of underlying components.

How to load a text file into a Hive table stored as sequence files

You cannot directly create a table stored as a sequence file and insert text into it. You must do this:

  1. Create a table stored as text
  2. Insert the text file into the text table
  3. Do a CTAS to create the table stored as a sequence file.
  4. Drop the text table if desired

Example:

CREATE TABLE test_txt(field1 int, field2 string)
ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t';

LOAD DATA INPATH '/path/to/file.tsv' INTO TABLE test_txt;

CREATE TABLE test STORED AS SEQUENCEFILE
AS SELECT * FROM test_txt;

DROP TABLE test_txt;

Insert into a MySQL table or update if exists

Check out REPLACE

http://dev.mysql.com/doc/refman/5.0/en/replace.html

REPLACE into table (id, name, age) values(1, "A", 19)

Simple PHP calculator

<?php 
$result = "";
class calculator
{
    var $a;
    var $b;

    function checkopration($oprator)
    {
        switch($oprator)
        {
            case '+':
            return $this->a + $this->b;
            break;

            case '-':
            return $this->a - $this->b;
            break;

            case '*':
            return $this->a * $this->b;
            break;

            case '/':
            return $this->a / $this->b;
            break;

            default:
            return "Sorry No command found";
        }   
    }
    function getresult($a, $b, $c)
    {
        $this->a = $a;
        $this->b = $b;
        return $this->checkopration($c);
    }
}

$cal = new calculator();
if(isset($_POST['submit']))
{   
    $result = $cal->getresult($_POST['n1'],$_POST['n2'],$_POST['op']);
}
?>

<form method="post">
<table align="center">
    <tr>
        <td><strong><?php echo $result; ?><strong></td>
    </tr>
    <tr>
        <td>Enter 1st Number</td>
        <td><input type="text" name="n1"></td>
    </tr>

    <tr>
        <td>Enter 2nd Number</td>
        <td><input type="text" name="n2"></td>
    </tr>

    <tr>
        <td>Select Oprator</td>
        <td><select name="op">
            <option value="+">+</option>
            <option value="-">-</option>
            <option value="*">*</option>
            <option value="/">/</option>
        </select></td>
    </tr>

    <tr>
        <td></td>
        <td><input type="submit" name="submit" value="                =                "></td>
    </tr>

</table>
</form>

What's a .sh file?

I know this is an old question and I probably won't help, but many Linux distributions(e.g., ubuntu) have a "Live cd/usb" function, so if you really need to run this script, you could try booting your computer into Linux. Just burn a .iso to a flash drive (here's how http://goo.gl/U1wLYA), start your computer with the drive plugged in, and press the F key for boot menu. If you choose "...USB...", you will boot into the OS you just put on the drive.

Understanding string reversal via slicing

I think the following makes a bit more sense for print strings in reverse, but maybe that's just me:

for char in reversed( myString ):  
  print( char, end = "" )

Correct way to detach from a container without stopping it

Old post but just exit then start it again... the issue is if you are on a windows machine Ctrl p or Ctrl P are tied to print... exiting the starting the container should not hurt anything

cell format round and display 2 decimal places

Another way is to use FIXED function, you can specify the number of decimal places but it defaults to 2 if the places aren't specified, i.e.

=FIXED(E5,2)

or just

=FIXED(E5)

How do I create a timer in WPF?

Adding to the above. You use the Dispatch timer if you want the tick events marshalled back to the UI thread. Otherwise I would use System.Timers.Timer.

SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder"

Please add the following dependencies to pom to resolve this issue.

<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>slf4j-simple</artifactId>
  <version>1.7.25</version>
  <scope>test</scope>
</dependency>

<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>slf4j-api</artifactId>
  <version>1.7.25</version>
</dependency>

Link a photo with the cell in excel

There is a much simpler way. Put your picture in a comment box within the description cell. That way you only have one column and when you sort the picture will always stay with the description. Okay... Right click the cell containing the description... Insert comment...right click the outer border... Format comment...colours and lines tab... Colour drop down...Fill effects...Picture tab...select picture...browse for your picture (it might be best to keep all pictures in one folder for ease of placement)...ok... you will probably need to go to the size tab and frig around with the height and width. Done... You now only need to mouse over the red in the top right corner of the cell and the picture will appear...like magic.

This method means that the row height can be kept to a minimum and the pictures can be as big as you like.

How SQL query result insert in temp table?

You can use select ... into ... to create and populate a temp table and then query the temp table to return the result.

select *
into #TempTable
from YourTable

select *
from #TempTable

Using grep to search for a string that has a dot in it

You can also search with -- option which basically ignores all the special characters and it won't be interpreted by grep.

$ cat foo |grep -- "0\.49"

Regular Expression to match string starting with a specific word

If you want to match anything that starts with "stop" including "stop going", "stop" and "stopping" use:

^stop

If you want to match the word stop followed by anything as in "stop going", "stop this", but not "stopped" and not "stopping" use:

^stop\W

Postgres FOR LOOP

Below is example you can use:

create temp table test2 (
  id1  numeric,
  id2  numeric,
  id3  numeric,
  id4  numeric,
  id5  numeric,
  id6  numeric,
  id7  numeric,
  id8  numeric,
  id9  numeric,
  id10 numeric) 
with (oids = false);

do
$do$
declare
     i int;
begin
for  i in 1..100000
loop
    insert into test2  values (random(), i * random(), i / random(), i + random(), i * random(), i / random(), i + random(), i * random(), i / random(), i + random());
end loop;
end;
$do$;

Using CSS to affect div style inside iframe

Use Jquery and wait till the source is loaded, This is how I have achieved(Used angular interval, you can use javascript setInterval method):

var addCssToIframe = function() {
    if ($('#myIframe').contents().find("head") != undefined) {
        $('#myIframe')
                .contents()
                .find("head")
                .append(
                        '<link rel="stylesheet" href="app/css/iframe.css" type="text/css" />');
        $interval.cancel(addCssInterval);
    }
};
var addCssInterval = $interval(addCssToIframe, 500, 0, false);

Detect iPhone/iPad purely by css

iPhone & iPod touch:

<link rel="stylesheet" media="only screen and (max-device-width: 480px)" href="../iphone.css" type="text/css" />

iPhone 4 & iPod touch 4G:

<link rel="stylesheet" media="only screen and (-webkit-min-device-pixel-ratio: 2)" type="text/css" href="../iphone4.css" />

iPad:

<link rel="stylesheet" media="only screen and (max-device-width: 1024px)" href="../ipad.css" type="text/css" />

Replacing from match to end-of-line

Use this, two<anything any number of times><end of line>

's/two.*$/BLAH/g'

How to check for a JSON response using RSpec?

You could parse the response body like this:

parsed_body = JSON.parse(response.body)

Then you can make your assertions against that parsed content.

parsed_body["foo"].should == "bar"

Pythonic way to combine FOR loop and IF statement

You can use generator expressions like this:

gen = (x for x in xyz if x not in a)

for x in gen:
    print x

How can I query for null values in entity framework?

Unfortunately in Entity Framework 5 DbContext the issue is still not fixed.

I used this workaround (works with MSSQL 2012 but ANSI NULLS setting might be deprecated in any future MSSQL version).

public class Context : DbContext
{

    public Context()
        : base("name=Context")
    {
        this.Database.Connection.StateChange += Connection_StateChange;
    }

    void Connection_StateChange(object sender, System.Data.StateChangeEventArgs e)
    {
        // Set ANSI_NULLS OFF when any connection is opened. This is needed because of a bug in Entity Framework
        // that is not fixed in EF 5 when using DbContext.
        if (e.CurrentState == System.Data.ConnectionState.Open)
        {
            var connection = (System.Data.Common.DbConnection)sender;
            using (var cmd = connection.CreateCommand())
            {
                cmd.CommandText = "SET ANSI_NULLS OFF";
                cmd.ExecuteNonQuery();
            }
        }
    }
}

It should be noted that it is a dirty workaround but it is one that can be implemented very quickly and works for all queries.

Difference between / and /* in servlet mapping url pattern

The essential difference between /* and / is that a servlet with mapping /* will be selected before any servlet with an extension mapping (like *.html), while a servlet with mapping / will be selected only after extension mappings are considered (and will be used for any request which doesn't match anything else---it is the "default servlet").

In particular, a /* mapping will always be selected before a / mapping. Having either prevents any requests from reaching the container's own default servlet.

Either will be selected only after servlet mappings which are exact matches (like /foo/bar) and those which are path mappings longer than /* (like /foo/*). Note that the empty string mapping is an exact match for the context root (http://host:port/context/).

See Chapter 12 of the Java Servlet Specification, available in version 3.1 at http://download.oracle.com/otndocs/jcp/servlet-3_1-fr-eval-spec/index.html.

Evenly space multiple views within a container view

Another approach might be to have the top and bottom labels have constraints relative to the view top and bottom, respectively, and have the middle view have top and bottom constraints relative to the first and third view, respectively.

Note that you have more control over constraints than it might seem by dragging views close to one another until guiding dashed lines appear - these indicate constraints between the two objects that will be formed instead of between the object and the superview.

In this case you would then want to alter the constraints to be "Greater than or equal to" the desired value, instead of "equal to" to allow them to resize. Not sure if this will do exactly what you want.

What's the difference between getRequestURI and getPathInfo methods in HttpServletRequest?

getPathInfo() gives the extra path information after the URI, used to access your Servlet, where as getRequestURI() gives the complete URI.

I would have thought they would be different, given a Servlet must be configured with its own URI pattern in the first place; I don't think I've ever served a Servlet from root (/).

For example if Servlet 'Foo' is mapped to URI '/foo' then I would have thought the URI:

/foo/path/to/resource

Would result in:

RequestURI = /foo/path/to/resource

and

PathInfo = /path/to/resource

Python 3 ImportError: No module named 'ConfigParser'

Compatibility of Python 2/3 for configparser can be solved simply by six library

from six.moves import configparser

Remove tracking branches no longer on remote

This worked for me:

git branch -r | awk '{print $1}' | egrep -v -f /dev/fd/0 <(git branch -vv | grep origin) | awk '{print $1}' | xargs git branch -d

How to create a circle icon button in Flutter?

I used this one because I like the customisation of the border-radius and size.

  Material( // pause button (round)
    borderRadius: BorderRadius.circular(50), // change radius size
    color: Colors.blue, //button colour
    child: InkWell(
      splashColor: Colors.blue[900], // inkwell onPress colour
      child: SizedBox(
        width: 35,height: 35, //customisable size of 'button'
        child: Icon(Icons.pause,color: Colors.white,size: 16,),
      ),
      onTap: () {}, // or use onPressed: () {}
    ),
  ),

  Material( // eye button (customised radius)
    borderRadius: BorderRadius.only(
        topRight: Radius.circular(10.0),
        bottomLeft: Radius.circular(50.0),),
    color: Colors.blue,
    child: InkWell(
      splashColor: Colors.blue[900], // inkwell onPress colour
      child: SizedBox(
        width: 40, height: 40, //customisable size of 'button'
        child: Icon(Icons.remove_red_eye,color: Colors.white,size: 16,),),
      onTap: () {}, // or use onPressed: () {}
    ),
  ),

enter image description here

PHP array delete by value (not key)

If you don't know its key it means it doesn't matter.

You could place the value as the key, it means it will instantly find the value. Better than using searching in all elements over and over again.

$messages=array();   
$messages[312] = 312;    
$messages[401] = 401;   
$messages[1599] = 1599;   
$messages[3] = 3;    

unset($messages[3]); // no search needed

Why is list initialization (using curly braces) better than the alternatives?

Basically copying and pasting from Bjarne Stroustrup's "The C++ Programming Language 4th Edition":

List initialization does not allow narrowing (§iso.8.5.4). That is:

  • An integer cannot be converted to another integer that cannot hold its value. For example, char to int is allowed, but not int to char.
  • A floating-point value cannot be converted to another floating-point type that cannot hold its value. For example, float to double is allowed, but not double to float.
  • A floating-point value cannot be converted to an integer type.
  • An integer value cannot be converted to a floating-point type.

Example:

void fun(double val, int val2) {

    int x2 = val;    // if val == 7.9, x2 becomes 7 (bad)

    char c2 = val2;  // if val2 == 1025, c2 becomes 1 (bad)

    int x3 {val};    // error: possible truncation (good)

    char c3 {val2};  // error: possible narrowing (good)

    char c4 {24};    // OK: 24 can be represented exactly as a char (good)

    char c5 {264};   // error (assuming 8-bit chars): 264 cannot be 
                     // represented as a char (good)

    int x4 {2.0};    // error: no double to int value conversion (good)

}

The only situation where = is preferred over {} is when using auto keyword to get the type determined by the initializer.

Example:

auto z1 {99};   // z1 is an int
auto z2 = {99}; // z2 is std::initializer_list<int>
auto z3 = 99;   // z3 is an int

Conclusion

Prefer {} initialization over alternatives unless you have a strong reason not to.

How do I bind a WPF DataGrid to a variable number of columns?

I've continued my research and have not found any reasonable way to do this. The Columns property on the DataGrid isn't something I can bind against, in fact it's read only.

Bryan suggested something might be done with AutoGenerateColumns so I had a look. It uses simple .Net reflection to look at the properties of the objects in ItemsSource and generates a column for each one. Perhaps I could generate a type on the fly with a property for each column but this is getting way off track.

Since this problem is so easily sovled in code I will stick with a simple extension method I call whenever the data context is updated with new columns:

public static void GenerateColumns(this DataGrid dataGrid, IEnumerable<ColumnSchema> columns)
{
    dataGrid.Columns.Clear();

    int index = 0;
    foreach (var column in columns)
    {
        dataGrid.Columns.Add(new DataGridTextColumn
        {
            Header = column.Name,
            Binding = new Binding(string.Format("[{0}]", index++))
        });
    }
}

// E.g. myGrid.GenerateColumns(schema);

How to read html from a url in python 3

urllib.request.urlopen(url).read() should return you the raw HTML page as a string.

How to find the operating system version using JavaScript?

I fork @Ludwig code and remove necessity of swfobject.

I just use swfobject code for detect flash version.

/**
 * JavaScript Client Detection
 * (C) viazenetti GmbH (Christian Ludwig)
 */
(function (window) {
    {
    var unknown = '-';

    // screen
    var screenSize = '';
    if (screen.width) {
        width = (screen.width) ? screen.width : '';
        height = (screen.height) ? screen.height : '';
        screenSize += '' + width + " x " + height;
    }

    //browser
    var nVer = navigator.appVersion;
    var nAgt = navigator.userAgent;
    var browser = navigator.appName;
    var version = '' + parseFloat(navigator.appVersion);
    var majorVersion = parseInt(navigator.appVersion, 10);
    var nameOffset, verOffset, ix;

    // Opera
    if ((verOffset = nAgt.indexOf('Opera')) != -1) {
        browser = 'Opera';
        version = nAgt.substring(verOffset + 6);
        if ((verOffset = nAgt.indexOf('Version')) != -1) {
        version = nAgt.substring(verOffset + 8);
        }
    }
    // MSIE
    else if ((verOffset = nAgt.indexOf('MSIE')) != -1) {
        browser = 'Microsoft Internet Explorer';
        version = nAgt.substring(verOffset + 5);
    }
    // Chrome
    else if ((verOffset = nAgt.indexOf('Chrome')) != -1) {
        browser = 'Chrome';
        version = nAgt.substring(verOffset + 7);
    }
    // Safari
    else if ((verOffset = nAgt.indexOf('Safari')) != -1) {
        browser = 'Safari';
        version = nAgt.substring(verOffset + 7);
        if ((verOffset = nAgt.indexOf('Version')) != -1) {
        version = nAgt.substring(verOffset + 8);
        }
    }
    // Firefox
    else if ((verOffset = nAgt.indexOf('Firefox')) != -1) {
        browser = 'Firefox';
        version = nAgt.substring(verOffset + 8);
    }
    // MSIE 11+
    else if (nAgt.indexOf('Trident/') != -1) {
        browser = 'Microsoft Internet Explorer';
        version = nAgt.substring(nAgt.indexOf('rv:') + 3);
    }
    // Other browsers
    else if ((nameOffset = nAgt.lastIndexOf(' ') + 1) < (verOffset = nAgt.lastIndexOf('/'))) {
        browser = nAgt.substring(nameOffset, verOffset);
        version = nAgt.substring(verOffset + 1);
        if (browser.toLowerCase() == browser.toUpperCase()) {
        browser = navigator.appName;
        }
    }
    // trim the version string
    if ((ix = version.indexOf(';')) != -1) version = version.substring(0, ix);
    if ((ix = version.indexOf(' ')) != -1) version = version.substring(0, ix);
    if ((ix = version.indexOf(')')) != -1) version = version.substring(0, ix);

    majorVersion = parseInt('' + version, 10);
    if (isNaN(majorVersion)) {
        version = '' + parseFloat(navigator.appVersion);
        majorVersion = parseInt(navigator.appVersion, 10);
    }

    // mobile version
    var mobile = /Mobile|mini|Fennec|Android|iP(ad|od|hone)/.test(nVer);

    // cookie
    var cookieEnabled = (navigator.cookieEnabled) ? true : false;

    if (typeof navigator.cookieEnabled == 'undefined' && !cookieEnabled) {
        document.cookie = 'testcookie';
        cookieEnabled = (document.cookie.indexOf('testcookie') != -1) ? true : false;
    }

    // system
    var os = unknown;
    var clientStrings = [
        {s:'Windows 10', r:/(Windows 10.0|Windows NT 10.0)/},
        {s:'Windows 8.1', r:/(Windows 8.1|Windows NT 6.3)/},
        {s:'Windows 8', r:/(Windows 8|Windows NT 6.2)/},
        {s:'Windows 7', r:/(Windows 7|Windows NT 6.1)/},
        {s:'Windows Vista', r:/Windows NT 6.0/},
        {s:'Windows Server 2003', r:/Windows NT 5.2/},
        {s:'Windows XP', r:/(Windows NT 5.1|Windows XP)/},
        {s:'Windows 2000', r:/(Windows NT 5.0|Windows 2000)/},
        {s:'Windows ME', r:/(Win 9x 4.90|Windows ME)/},
        {s:'Windows 98', r:/(Windows 98|Win98)/},
        {s:'Windows 95', r:/(Windows 95|Win95|Windows_95)/},
        {s:'Windows NT 4.0', r:/(Windows NT 4.0|WinNT4.0|WinNT|Windows NT)/},
        {s:'Windows CE', r:/Windows CE/},
        {s:'Windows 3.11', r:/Win16/},
        {s:'Android', r:/Android/},
        {s:'Open BSD', r:/OpenBSD/},
        {s:'Sun OS', r:/SunOS/},
        {s:'Linux', r:/(Linux|X11)/},
        {s:'iOS', r:/(iPhone|iPad|iPod)/},
        {s:'Mac OS X', r:/Mac OS X/},
        {s:'Mac OS', r:/(MacPPC|MacIntel|Mac_PowerPC|Macintosh)/},
        {s:'QNX', r:/QNX/},
        {s:'UNIX', r:/UNIX/},
        {s:'BeOS', r:/BeOS/},
        {s:'OS/2', r:/OS\/2/},
        {s:'Search Bot', r:/(nuhk|Googlebot|Yammybot|Openbot|Slurp|MSNBot|Ask Jeeves\/Teoma|ia_archiver)/}
    ];
    for (var id in clientStrings) {
        var cs = clientStrings[id];
        if (cs.r.test(nAgt)) {
        os = cs.s;
        break;
        }
    }

    var osVersion = unknown;

    if (/Windows/.test(os)) {
        osVersion = /Windows (.*)/.exec(os)[1];
        os = 'Windows';
    }

    switch (os) {
        case 'Mac OS X':
        osVersion = /Mac OS X (10[\.\_\d]+)/.exec(nAgt)[1];
        break;

        case 'Android':
        osVersion = /Android ([\.\_\d]+)/.exec(nAgt)[1];
        break;

        case 'iOS':
        osVersion = /OS (\d+)_(\d+)_?(\d+)?/.exec(nVer);
        osVersion = osVersion[1] + '.' + osVersion[2] + '.' + (osVersion[3] | 0);
        break;
    }

    var flashVersion = 'no check', d, fv = [];
    if (typeof navigator.plugins !== 'undefined' && typeof navigator.plugins["Shockwave Flash"] === "object") {
        d = navigator.plugins["Shockwave Flash"].description;
        if (d && !(typeof navigator.mimeTypes !== 'undefined' && navigator.mimeTypes["application/x-shockwave-flash"] && !navigator.mimeTypes["application/x-shockwave-flash"].enabledPlugin)) { // navigator.mimeTypes["application/x-shockwave-flash"].enabledPlugin indicates whether plug-ins are enabled or disabled in Safari 3+
        d = d.replace(/^.*\s+(\S+\s+\S+$)/, "$1");
        fv[0] = parseInt(d.replace(/^(.*)\..*$/, "$1"), 10);
        fv[1] = parseInt(d.replace(/^.*\.(.*)\s.*$/, "$1"), 10);
        fv[2] = /[a-zA-Z]/.test(d) ? parseInt(d.replace(/^.*[a-zA-Z]+(.*)$/, "$1"), 10) : 0;
        }
    } else if (typeof window.ActiveXObject !== 'undefined') {
        try {
        var a = new ActiveXObject("ShockwaveFlash.ShockwaveFlash");
        if (a) { // a will return null when ActiveX is disabled
            d = a.GetVariable("$version");
            if (d) {
            d = d.split(" ")[1].split(",");
            fv = [parseInt(d[0], 10), parseInt(d[1], 10), parseInt(d[2], 10)];
            }
        }
        }
        catch(e) {}
    }
    if (fv.length) {
        flashVersion = fv[0] + '.' + fv[1] + ' r' + fv[2];
    }    
    }

    window.jscd = {
    screen: screenSize,
    browser: browser,
    browserVersion: version,
    mobile: mobile,
    os: os,
    osVersion: osVersion,
    cookies: cookieEnabled,
    flashVersion: flashVersion
    };
}(this));

alert(
    'OS: ' + jscd.os +' '+ jscd.osVersion + '\n'+
    'Browser: ' + jscd.browser +' '+ jscd.browserVersion + '\n' + 
    'Mobile: ' + jscd.mobile + '\n' +
    'Flash: ' + jscd.flashVersion + '\n' +
    'Cookies: ' + jscd.cookies + '\n' +
    'Screen Size: ' + jscd.screen + '\n\n' +
    'Full User Agent: ' + navigator.userAgent
);

Declare a variable in DB2 SQL

I imagine this forum posting, which I quote fully below, should answer the question.


Inside a procedure, function, or trigger definition, or in a dynamic SQL statement (embedded in a host program):

BEGIN ATOMIC
 DECLARE example VARCHAR(15) ;
 SET example = 'welcome' ;
 SELECT *
 FROM   tablename
 WHERE  column1 = example ;
END

or (in any environment):

WITH t(example) AS (VALUES('welcome'))
SELECT *
FROM   tablename, t
WHERE  column1 = example

or (although this is probably not what you want, since the variable needs to be created just once, but can be used thereafter by everybody although its content will be private on a per-user basis):

CREATE VARIABLE example VARCHAR(15) ;
SET example = 'welcome' ;
SELECT *
FROM   tablename
WHERE  column1 = example ;

scrollIntoView Scrolls just too far

My main idea is creating a tempDiv above the view which we want to scroll to. It work well without lagging in my project.

scrollToView = (element, offset) => {
    var rect = element.getBoundingClientRect();
    var targetY = rect.y + window.scrollY - offset;

    var tempDiv;
    tempDiv = document.getElementById("tempDiv");
    if (tempDiv) {
        tempDiv.style.top = targetY + "px";
    } else {
        tempDiv = document.createElement('div');
        tempDiv.id = "tempDiv";
        tempDiv.style.background = "#F00";
        tempDiv.style.width = "10px";
        tempDiv.style.height = "10px";
        tempDiv.style.position = "absolute";
        tempDiv.style.top = targetY + "px";
        document.body.appendChild(tempDiv);
    }

    tempDiv.scrollIntoView({ behavior: 'smooth', block: 'start' });
}

Example using

onContactUsClick = () => {
    this.scrollToView(document.getElementById("contact-us"), 48);
}

Hope it help

What's the difference between ASCII and Unicode?

ASCII and Unicode are two character encodings. Basically, they are standards on how to represent difference characters in binary so that they can be written, stored, transmitted, and read in digital media. The main difference between the two is in the way they encode the character and the number of bits that they use for each. ASCII originally used seven bits to encode each character. This was later increased to eight with Extended ASCII to address the apparent inadequacy of the original. In contrast, Unicode uses a variable bit encoding program where you can choose between 32, 16, and 8-bit encodings. Using more bits lets you use more characters at the expense of larger files while fewer bits give you a limited choice but you save a lot of space. Using fewer bits (i.e. UTF-8 or ASCII) would probably be best if you are encoding a large document in English.

One of the main reasons why Unicode was the problem arose from the many non-standard extended ASCII programs. Unless you are using the prevalent page, which is used by Microsoft and most other software companies, then you are likely to encounter problems with your characters appearing as boxes. Unicode virtually eliminates this problem as all the character code points were standardized.

Another major advantage of Unicode is that at its maximum it can accommodate a huge number of characters. Because of this, Unicode currently contains most written languages and still has room for even more. This includes typical left-to-right scripts like English and even right-to-left scripts like Arabic. Chinese, Japanese, and the many other variants are also represented within Unicode. So Unicode won’t be replaced anytime soon.

In order to maintain compatibility with the older ASCII, which was already in widespread use at the time, Unicode was designed in such a way that the first eight bits matched that of the most popular ASCII page. So if you open an ASCII encoded file with Unicode, you still get the correct characters encoded in the file. This facilitated the adoption of Unicode as it lessened the impact of adopting a new encoding standard for those who were already using ASCII.

Summary:

1.ASCII uses an 8-bit encoding while Unicode uses a variable bit encoding.
2.Unicode is standardized while ASCII isn’t.
3.Unicode represents most written languages in the world while ASCII does not.
4.ASCII has its equivalent within Unicode.

Taken From: http://www.differencebetween.net/technology/software-technology/difference-between-unicode-and-ascii/#ixzz4zEjnxPhs

Can I execute a function after setState is finished updating?

Making setState return a Promise

In addition to passing a callback to setState() method, you can wrap it around an async function and use the then() method -- which in some cases might produce a cleaner code:

(async () => new Promise(resolve => this.setState({dummy: true}), resolve)()
    .then(() => { console.log('state:', this.state) });

And here you can take this one more step ahead and make a reusable setState function that in my opinion is better than the above version:

const promiseState = async state =>
    new Promise(resolve => this.setState(state, resolve));

promiseState({...})
    .then(() => promiseState({...})
    .then(() => {
        ...  // other code
        return promiseState({...});
    })
    .then(() => {...});

This works fine in React 16.4, but I haven't tested it in earlier versions of React yet.

Also worth mentioning that keeping your callback code in componentDidUpdate method is a better practice in most -- probably all, cases.

origin 'http://localhost:4200' has been blocked by CORS policy in Angular7

You are all good at Angular side even postman not raise the cors policy issue. This type of issue is solved at back-end side in major cases.

If you are using Spring boot the you can avoid this issue by placing this annotation at your controller class or at any particular method.

@CrossOrigin(origins = "http://localhost:4200")

In case of global configuration with spring boot configure following two class:

`

@EnableWebSecurity
@AllArgsConstructor

public class SecurityConfig extends WebSecurityConfigurerAdapter {
@Override
    public void configure(HttpSecurity httpSecurity) throws Exception{
        httpSecurity.csrf().disable()
        .authorizeRequests()
        .antMatchers("/api1/**").permitAll()
        .antMatchers("/api2/**").permitAll()
        .antMatchers("/api3/**").permitAll()
        
}
`

@Configuration
@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void addCorsMappings(CorsRegistry corsRegistry) {
        corsRegistry.addMapping("/**")
                .allowedOrigins("http://localhost:4200")
                .allowedMethods("*")
                .maxAge(3600L)
                .allowedHeaders("*")
                .exposedHeaders("Authorization")
                .allowCredentials(true);
    }

Render Content Dynamically from an array map function in React Native

Don't forget to return the mapped array , like:

lapsList() {

    return this.state.laps.map((data) => {
      return (
        <View><Text>{data.time}</Text></View>
      )
    })

}

Reference for the map() method: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map

JAVA_HOME is set to an invalid directory:

On Window 10, the problem was with the semicolon ;.

Go to edit the system environment variables and delete the semicolon at the end of JAVA_HOME value C:\Program Files\Java\jdk1.8.0_144

In other words, convert this C:\Program Files\Java\jdk1.8.0_12; to C:\Program Files\Java\jdk1.8.0_12

You might have to delete your entry in the Windows Dialog and create a new one. If you ever had multiple entries and get the bigger Form view, Windows automatically inserts a ; at the end of each entry, even if you only have one entry left.

Why Is Subtracting These Two Times (in 1927) Giving A Strange Result?

As others said, it's a time change in 1927 in Shanghai.

It was 23:54:07 in Shanghai, in the local standard time, but then after 5 minutes and 52 seconds, it turned to the next day at 00:00:00, and then local standard time changed back to 23:54:08. So, that's why the difference between the two times is 343 seconds, not 1 second, as you would have expected.

The time can also mess up in other places like the US. The US has Daylight Saving Time. When the Daylight Saving Time starts the time goes forward 1 hour. But after a while, the Daylight Saving Time ends, and it goes backward 1 hour back to the standard time zone. So sometimes when comparing times in the US the difference is about 3600 seconds not 1 second.

But there is something different about these two-time changes. The latter changes continuously and the former was just a change. It didn't change back or change again by the same amount.

It's better to use UTC unless if needed to use non-UTC time like in display.

What is the difference between MVC and MVVM?

For one thing, MVVM is a progression of the MVC pattern which uses XAML to handle the display. This article outlines some of the facets of the two.

The main thrust of the Model/View/ViewModel architecture seems to be that on top of the data (”the Model”), there’s another layer of non-visual components (”the ViewModel”) that map the concepts of the data more closely to the concepts of the view of the data (”the View”). It’s the ViewModel that the View binds to, not the Model directly.

When to use IList and when to use List

I would agree with Lee's advice for taking parameters, but not returning.

If you specify your methods to return an interface that means you are free to change the exact implementation later on without the consuming method ever knowing. I thought I'd never need to change from a List<T> but had to later change to use a custom list library for the extra functionality it provided. Because I'd only returned an IList<T> none of the people that used the library had to change their code.

Of course that only need apply to methods that are externally visible (i.e. public methods). I personally use interfaces even in internal code, but as you are able to change all the code yourself if you make breaking changes it's not strictly necessary.

how to get date of yesterday using php?

there you go

date('d.m.Y',strtotime("-1 days"));

this will work also if month change

How to format date in angularjs

var app=angular.module('myApp',[]);
        app.controller('myController',function($scope){         
              $scope.names = ['1288323623006','1388323623006'];

        });

Here Controller name is "myController" and app name is "myApp".

<div ng-app="myApp" ng-controller="myController">
        <ul>
            <li ng-repeat="x in names">
                {{x | date:'mm-dd-yyyy'}}

            </li>

        </ul>
    </div>

Result will look like this :- * 10-29-2010 * 01-03-2013

Can I make 'git diff' only the line numbers AND changed file names?

On git version 2.17.1, there isn't a built-in flag to achieve this purpose.

Here's an example command to filter out the filename and line numbers from an unified diff:

git diff --unified=0 | grep -Po '^diff --cc \K.*|^@@@( -[0-9]+,[0-9]+){2} \+\K[0-9]+(?=(,[0-9]+)? @@@)' | paste -s -d':'

For example, the unified diff:

$ git diff --unified=0
diff --cc foobar
index b436f31,df63c58..0000000
--- a/foobar
+++ b/foobar
@@@ -1,2 -1,2 +1,6 @@@ Line abov
++<<<<<<< HEAD
 +bar
++=======
+ foo
++>>>>>>> Commit message

Will result in:

? git diff --unified=0 | grep -Po '^diff --cc \K.*|^@@@( -[0-9]+,[0-9]+){2} \+\K[0-9]+(?=(,[0-9]+)? @@@)' | paste -s -d':'
foobar:1

To match the output of commands in common grep match results:

$ git diff --unified=0 | grep -Po '^diff --cc \K.*|^@@@( -[0-9]+,[0-9]+){2} \+\K[0-9]+(?=(,[0-9]+)? )| @@@.*' | sed -e '0~3{s/ @@@[ ]\?//}' | sed '2~3 s/$/\n1/g' | sed "N;N;N;s/\n/:/g"
foobar:1:1:Line abov
  1. grep -Po '^diff --cc \K.*|^@@@( -[0-9]+,[0-9]+){2} \+\K[0-9]+(?=(,[0-9]+)? ): Match filename from diff --cc <filename> OR Match line number from @@@ <from-file-range> <from-file-range> <to-file-range> OR Match remaining text after @@@.
  2. sed -e '0~3{s/ @@@[ ]\?//}': Remove @@@[ ]\? from every 3rd line to get the optional 1 line context before ++<<<<<<< HEAD.
  3. sed '2~3 s/$/\n1/g': Add \n1 every 3 lines between the 2nd and 3rd line for the column number.
  4. sed "N;N;N;s/\n/:/g": Join every 3 lines with a :.

Better way to sum a property value in an array

You can do the following:

$scope.traveler.map(o=>o.Amount).reduce((a,c)=>a+c);

java.lang.UnsupportedClassVersionError: Unsupported major.minor version 51.0 (unable to load class frontend.listener.StartupListener)

What is your output when you do java -version? This will tell you what version the running JVM is.

The Unsupported major.minor version 51.0 error could mean:

  • Your server is running a lower Java version then the one used to compile your Servlet and vice versa

Either way, uninstall all JVM runtimes including JDK and download latest and re-install. That should fix any Unsupported major.minor error as you will have the lastest JRE and JDK (Maybe even newer then the one used to compile the Servlet)

See: http://www.java.com/en/download/manual.jsp (7 Update 25 )

and here: http://www.oracle.com/technetwork/java/javase/downloads/index.html (Java Platform (JDK) 7u25)

for the latest version of the JRE and JDK respectively.

EDIT:

Most likely your code was written in Java7 however maybe it was done using Java7update4 and your system is running Java7update3. Thus they both are effectively the same major version but the minor versions differ. Only the larger minor version is backward compatible with the lower minor version.

Edit 2 : If you have more than one jdk installed on your pc. you should check that Apache Tomcat is using the same one (jre) you are compiling your programs with. If you installed a new jdk after installing apache it normally won't select the new version.

Fatal error: Call to a member function bind_param() on boolean

The problem lies in:

$query = $this->db->conn->prepare('SELECT value, param FROM ws_settings WHERE name = ?');
$query->bind_param('s', $setting);

The prepare() method can return false and you should check for that. As for why it returns false, perhaps the table name or column names (in SELECT or WHERE clause) are not correct?

Also, consider use of something like $this->db->conn->error_list to examine errors that occurred parsing the SQL. (I'll occasionally echo the actual SQL statement strings and paste into phpMyAdmin to test, too, but there's definitely something failing there.)

Undefined variable: $_SESSION

Another possibility for this warning (and, most likely, problems with app behavior) is that the original author of the app relied on session.auto_start being on (defaults to off)

If you don't want to mess with the code and just need it to work, you can always change php configuration and restart php-fpm (if this is a web app):

/etc/php.d/my-new-file.ini :

session.auto_start = 1

(This is correct for CentOS 8, adjust for your OS/packaging)

How do I find the current machine's full hostname in C (hostname and domain information)?

gethostname() is POSIX way to get local host name. Check out man.

BSD function getdomainname() can give you domain name so you can build fully qualified hostname. There is no POSIX way to get a domain I'm afraid.

Centering FontAwesome icons vertically and horizontally

I just lowered the height to 28px on the .login-icon [class*='icon-'] Here's the fiddle: http://jsfiddle.net/mZHg7/

.login-icon [class*='icon-']{
    height: 28px;
    width: 50px;
    display: inline-block;
    text-align: center;
    vertical-align: baseline;
}

Iterating through a string word by word

Using nltk.

from nltk.tokenize import sent_tokenize, word_tokenize
sentences = sent_tokenize("This is a string.")
words_in_each_sentence = word_tokenize(sentences)

You may use TweetTokenizer for parsing casual text with emoticons and such.

VBA EXCEL To Prompt User Response to Select Folder and Return the Path as String Variable

Consider:

Function GetFolder() As String
    Dim fldr As FileDialog
    Dim sItem As String
    Set fldr = Application.FileDialog(msoFileDialogFolderPicker)
    With fldr
        .Title = "Select a Folder"
        .AllowMultiSelect = False
        .InitialFileName = Application.DefaultFilePath
        If .Show <> -1 Then GoTo NextCode
        sItem = .SelectedItems(1)
    End With
NextCode:
    GetFolder = sItem
    Set fldr = Nothing
End Function

This code was adapted from Ozgrid

and as jkf points out, from Mr Excel

INNER JOIN same table

Perhaps this should be the select (if I understand the question correctly)

select user.user_fname, user.user_lname, parent.user_fname, parent.user_lname
... As before

How can I use async/await at the top level?

i like this clever syntax to do async work from an entrypoint

void async function main() {
  await doSomeWork()
  await doMoreWork()
}()

PermGen elimination in JDK 8

PermGen space is replaced by MetaSpace in Java 8. The PermSize and MaxPermSize JVM arguments are ignored and a warning is issued if present at start-up.

Most allocations for the class metadata are now allocated out of native memory. * The classes that were used to describe class metadata have been removed.

Main difference between old PermGen and new MetaSpace is, you don't have to mandatory define upper limit of memory usage. You can keep MetaSpace space limit unbounded. Thus when memory usage increases you will not get OutOfMemoryError error. Instead the reserved native memory is increased to full-fill the increase memory usage.

You can define the max limit of space for MetaSpace, and then it will throw OutOfMemoryError : Metadata space. Thus it is important to define this limit cautiously, so that we can avoid memory waste.

Allow access permission to write in Program Files of Windows 7

Add new item in the project: Application Manifest and save it.

Now open this file and look for <requestExecutionLevel>. It must be set to asInvoker.

Change it to highestAvailable. Now on executing your application, a prompt will appear asking for permission. Click yes!

Thats all :) now you can write and read from the system32 or any other file which requires admin right

You can verify your application by sigcheck.

sigcheck.exe -m yourapp.exe

And in the output check for element requestedExecutionLevel.

How to use Typescript with native ES6 Promises

This the most recent way to do this, the above answer is outdated:

typings install --global es6-promise

How to get just the responsive grid from Bootstrap 3?

In Bootstrap 4, there are already separated files in their GitHub. You can find them here

https://github.com/twbs/bootstrap/tree/main/dist/css

Should each and every table have a primary key?

In short, no. However, you need to keep in mind that certain client access CRUD operations require it. For future proofing, I tend to always utilize primary keys.

Whats the CSS to make something go to the next line in the page?

There are two options that I can think of, but without more details, I can't be sure which is the better:

#elementId {
    display: block;
}

This will force the element to a 'new line' if it's not on the same line as a floated element.

#elementId {
     clear: both;
}

This will force the element to clear the floats, and move to a 'new line.'

In the case of the element being on the same line as another that has position of fixed or absolute nothing will, so far as I know, force a 'new line,' as those elements are removed from the document's normal flow.

"Application tried to present modally an active controller"?

The same problem error happened to me when I tried to present a child view controller instead of its UINavigationViewController parent

Generating random whole numbers in JavaScript in a specific range?

My method of generating random number between 0 and n, where n <= 10 (n excluded):

Math.floor((Math.random() * 10) % n)

Android: checkbox listener

Translation of the accepted answer by Chris into Kotlin:

val checkBox: CheckBox = findViewById(R.id.chk)
checkBox.setOnCheckedChangeListener { buttonView, isChecked ->
    // Code here 
}

Could not find or load main class with a Jar File

Sometimes could missing the below line under <build> tag in pom.xml when packaging through maven. since src folder contains your java files

<sourceDirectory>src</sourceDirectory>

Getting reference to the top-most view/window in iOS application

I'm sticking to the question as the title states and not the discussion. Which view is top visible on any given point?

@implementation UIView (Extra)

- (UIView *)findTopMostViewForPoint:(CGPoint)point
{
    for(int i = self.subviews.count - 1; i >= 0; i--)
    {
        UIView *subview = [self.subviews objectAtIndex:i];
        if(!subview.hidden && CGRectContainsPoint(subview.frame, point))
        {
            CGPoint pointConverted = [self convertPoint:point toView:subview];
            return [subview findTopMostViewForPoint:pointConverted];
        }
    }

    return self;
}

- (UIWindow *)topmostWindow
{
    UIWindow *topWindow = [[[UIApplication sharedApplication].windows sortedArrayUsingComparator:^NSComparisonResult(UIWindow *win1, UIWindow *win2) {
        return win1.windowLevel - win2.windowLevel;
    }] lastObject];
    return topWindow;
}

@end

Can be used directly with any UIWindow as receiver or any UIView as receiver.

How to check if a date is in a given range?

Convert both dates to timestamps then do

pseudocode:

if date_from_user > start_date && date_from_user < end_date
    return true

What is the significance of url-pattern in web.xml and how to configure servlet?

url-pattern is used in web.xml to map your servlet to specific URL. Please see below xml code, similar code you may find in your web.xml configuration file.

<servlet>
    <servlet-name>AddPhotoServlet</servlet-name>  //servlet name
    <servlet-class>upload.AddPhotoServlet</servlet-class>  //servlet class
</servlet>
 <servlet-mapping>
    <servlet-name>AddPhotoServlet</servlet-name>   //servlet name
    <url-pattern>/AddPhotoServlet</url-pattern>  //how it should appear
</servlet-mapping>

If you change url-pattern of AddPhotoServlet from /AddPhotoServlet to /MyUrl. Then, AddPhotoServlet servlet can be accessible by using /MyUrl. Good for the security reason, where you want to hide your actual page URL.

Java Servlet url-pattern Specification:

  1. A string beginning with a '/' character and ending with a '/*' suffix is used for path mapping.
  2. A string beginning with a '*.' prefix is used as an extension mapping.
  3. A string containing only the '/' character indicates the "default" servlet of the application. In this case the servlet path is the request URI minus the context path and the path info is null.
  4. All other strings are used for exact matches only.

Reference : Java Servlet Specification

You may also read this Basics of Java Servlet

ab load testing

hey I understand this is an old thread but I have a query in regards to apachebenchmarking. how do you collect the metrics from apache benchmarking. P.S: I have to do it via telegraf and put it to influxdb . any suggestions/advice/help would be appreciated. Thanks a ton.

Change link color of the current page with CSS

@Presto Thanks! Yours worked perfectly for me, but I came up with a simpler version to save changing everything around.

Add a <span> tag around the desired link text, specifying class within. (e.g. home tag)

<nav id="top-menu">
    <ul>
        <li> <a href="home.html"><span class="currentLink">Home</span></a> </li>
        <li> <a href="about.html">About</a> </li>
        <li> <a href="cv.html">CV</a> </li>
        <li> <a href="photos.html">Photos</a> </li>
        <li> <a href="archive.html">Archive</a> </li>
        <li> <a href="contact.html">Contact</a></li>
    </ul>
</nav>

Then edit your CSS accordingly:

.currentLink {
    color:#baada7;
}

How to get memory available or used in C#

You can use:

Process proc = Process.GetCurrentProcess();

To get the current process and use:

proc.PrivateMemorySize64;

To get the private memory usage. For more information look at this link.