Programs & Examples On #Scalac

scalac - Compiler for the Scala 2 language

Intermediate language used in scalac?

The nearest equivalents would be icode and bcode as used by scalac, view Miguel Garcia's site on the Scalac optimiser for more information, here: http://magarciaepfl.github.io/scala/

You might also consider Java bytecode itself to be your intermediate representation, given that bytecode is the ultimate output of scalac.

Or perhaps the true intermediate is something that the JIT produces before it finally outputs native instructions?

Ultimately though... There's no single place that you can point at an claim "there's the intermediate!". Scalac works in phases that successively change the abstract syntax tree, every single phase produces a new intermediate. The whole thing is like an onion, and it's very hard to try and pick out one layer as somehow being more significant than any other.

Elegant way to create empty pandas DataFrame with NaN of type float

You can try this line of code:

pdDataFrame = pd.DataFrame([np.nan] * 7)

This will create a pandas dataframe of size 7 with NaN of type float:

if you print pdDataFrame the output will be:

     0
0   NaN
1   NaN
2   NaN
3   NaN
4   NaN
5   NaN
6   NaN

Also the output for pdDataFrame.dtypes is:

0    float64
dtype: object

Easy interview question got harder: given numbers 1..100, find the missing number(s) given exactly k are missing

I think this can be done without any complex mathematical equations and theories. Below is a proposal for an in place and O(2n) time complexity solution:

Input form assumptions :

# of numbers in bag = n

# of missing numbers = k

The numbers in the bag are represented by an array of length n

Length of input array for the algo = n

Missing entries in the array (numbers taken out of the bag) are replaced by the value of the first element in the array.

Eg. Initially bag looks like [2,9,3,7,8,6,4,5,1,10]. If 4 is taken out, value of 4 will become 2 (the first element of the array). Therefore after taking 4 out the bag will look like [2,9,3,7,8,6,2,5,1,10]

The key to this solution is to tag the INDEX of a visited number by negating the value at that INDEX as the array is traversed.

    IEnumerable<int> GetMissingNumbers(int[] arrayOfNumbers)
    {
        List<int> missingNumbers = new List<int>();
        int arrayLength = arrayOfNumbers.Length;

        //First Pass
        for (int i = 0; i < arrayLength; i++)
        {
            int index = Math.Abs(arrayOfNumbers[i]) - 1;
            if (index > -1)
            {
                arrayOfNumbers[index] = Math.Abs(arrayOfNumbers[index]) * -1; //Marking the visited indexes
            }
        }

        //Second Pass to get missing numbers
        for (int i = 0; i < arrayLength; i++)
        {                
            //If this index is unvisited, means this is a missing number
            if (arrayOfNumbers[i] > 0)
            {
                missingNumbers.Add(i + 1);
            }
        }

        return missingNumbers;
    }

How to get bean using application context in spring boot

Just use:

org.springframework.beans.factory.BeanFactory#getBean(java.lang.Class)

Example:

@Component
public class Example {

    @Autowired
    private ApplicationContext context;

    public MyService getMyServiceBean() {
        return context.getBean(MyService.class);
    }

    // your code uses getMyServiceBean()
}

VirtualBox error "Failed to open a session for the virtual machine"

For windows users ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

I had the same issue, and this trick works for me

  1. Goto control panel
  2. Open Uninstall program
  3. Click on turn windows features on or off
  4. Scroll down and find the hyper-V folder.
  5. Uncheck the Hyper-V.
  6. Apply changes and restart your system.
  7. Now here you go... Open your virtual box and start the os you want.

Hope this helps..

How To Launch Git Bash from DOS Command Line?

I'm not sure exactly what you mean by "full Git Bash environment", but I get the nice prompt if I do

"C:\Program Files\Git\bin\sh.exe" --login

In PowerShell

& 'C:\Program Files\Git\bin\sh.exe' --login

The --login switch makes the shell execute the login shell startup files.

How can I find the OWNER of an object in Oracle?

Oracle views like ALL_TABLES and ALL_CONSTRAINTS have an owner column, which you can use to restrict your query. There are also variants of these tables beginning with USER instead of ALL, which only list objects which can be accessed by the current user.

One of these views should help to solve your problem. They always worked fine for me for similar problems.

Percentage Height HTML 5/CSS

Sometimes, you may want to conditionally set the height of a div, such as when the entire content is less than the height of the screen. Setting all parent elements to 100% will cut off content when it is longer than the screen size.

So, the way to get around this is to set the min-height:

Continue to let the parent elements automatically adjust their height Then in your main div, subtract the pixel sizes of the header and footer div from 100vh (viewport units). In css, something like:

min-height: calc(100vh - 246px);

100vh is full length of the screen, minus the surrounding divs. By setting min-height and not height, content longer than screen will continue to flow, instead of getting cut off.

Is there a reason for C#'s reuse of the variable in a foreach?

Having been bitten by this, I have a habit of including locally defined variables in the innermost scope which I use to transfer to any closure. In your example:

foreach (var s in strings)
    query = query.Where(i => i.Prop == s); // access to modified closure

I do:

foreach (var s in strings)
{
    string search = s;
    query = query.Where(i => i.Prop == search); // New definition ensures unique per iteration.
}        

Once you have that habit, you can avoid it in the very rare case you actually intended to bind to the outer scopes. To be honest, I don't think I have ever done so.

How to show and update echo on same line

My favorite way is called do the sleep to 50. here i variable need to be used inside echo statements.

for i in $(seq 1 50); do
  echo -ne "$i%\033[0K\r"
  sleep 50
done
echo "ended"

onchange file input change img src and change image color

You need to send this object only instead of this.value while calling onchange

<input type='file' id="upload" onchange="readURL(this)" />

because you are using input variable as this in your function, like at line

var url = input.value;// reading value property of input element

Working DEMO

EDIT - Try using jQuery like below --

remove onchange from input field :

<input type='file' id="upload" >

Bind onchange event to input field :

$(function(){
  $('#upload').change(function(){
    var input = this;
    var url = $(this).val();
    var ext = url.substring(url.lastIndexOf('.') + 1).toLowerCase();
    if (input.files && input.files[0]&& (ext == "gif" || ext == "png" || ext == "jpeg" || ext == "jpg")) 
     {
        var reader = new FileReader();

        reader.onload = function (e) {
           $('#img').attr('src', e.target.result);
        }
       reader.readAsDataURL(input.files[0]);
    }
    else
    {
      $('#img').attr('src', '/assets/no_preview.png');
    }
  });

});

jQuery Demo

CSS: how to get scrollbars for div inside container of fixed height

FWIW, here is my approach = a simple one that works for me:

<div id="outerDivWrapper">
   <div id="outerDiv">
      <div id="scrollableContent">
blah blah blah
      </div>
   </div>
</div>

html, body {
   height: 100%;
   margin: 0em;
}

#outerDivWrapper, #outerDiv {
   height: 100%;
   margin: 0em;
}

#scrollableContent {
   height: 100%;
   margin: 0em;
   overflow-y: auto;
}

Get city name using geolocation

Another approach to this is to use my service, http://ipinfo.io, which returns the city, region and country name based on the user's current IP address. Here's a simple example:

$.get("http://ipinfo.io", function(response) {
    console.log(response.city, response.country);
}, "jsonp");

Here's a more detailed JSFiddle example that also prints out the full response information, so you can see all of the available details: http://jsfiddle.net/zK5FN/2/

Using a RegEx to match IP addresses in Python

str = "255.255.255.255"
print(str.split('.'))

list1 = str.split('.')

condition=0

if len(list1)==4:
    for i in list1:
        if int(i)>=0 and int(i)<=255:
            condition=condition+1

if condition!=4:
    print("Given number is not IP address")
else:
    print("Given number is valid IP address")

How to find list of possible words from a letter matrix [Boggle Solver]

I wrote my solver in C++. I implemented a custom tree structure. I'm not sure it can be considered a trie but it's similar. Each node has 26 branches, 1 for each letter of the alphabet. I traverse the branches of the boggle board in parallel with the branches of my dictionary. If the branch does not exist in the dictionary, I stop searching it on the Boggle board. I convert all the letters on the board to ints. So 'A' = 0. Since it's just arrays, lookup is always O(1). Each node stores if it completes a word and how many words exist in its children. The tree is pruned as words are found to reduce repeatedly searching for the same words. I believe pruning is also O(1).

CPU: Pentium SU2700 1.3GHz
RAM: 3gb

Loads dictionary of 178,590 words in < 1 second.
Solves 100x100 Boggle (boggle.txt) in 4 seconds. ~44,000 words found.
Solving a 4x4 Boggle is too fast to provide a meaningful benchmark. :)

Fast Boggle Solver GitHub Repo

How to Export-CSV of Active Directory Objects?

From a Windows Server OS execute the following command for a dump of the entire Active Director:

csvde -f test.csv

This command is very broad and will give you more than necessary information. To constrain the records to only user records, you would instead want:

csvde -f test.csv -r objectClass=user 

You can further restrict the command to give you only the fields you need relevant to the search requested such as:

csvde -f test.csv -r objectClass=user -l DN, sAMAccountName, department, memberOf

If you have an Exchange server and each user associated with a live person has a mailbox (as opposed to generic accounts for kiosk / lab workstations) you can use mailNickname in place of sAMAccountName.

Given two directory trees, how can I find out which files differ by content?

The command I use is:

diff -qr dir1/ dir2/

It is exactly the same as Mark's :) But his answer bothered me as it uses different types of flags, and it made me look twice. Using Mark's more verbose flags it would be:

diff  --brief --recursive dir1/ dir2/

I apologise for posting when the other answer is perfectly acceptable. Could not stop myself... working on being less pedantic.

Improve subplot size/spacing with many subplots in matplotlib

Try using plt.tight_layout

As a quick example:

import matplotlib.pyplot as plt

fig, axes = plt.subplots(nrows=4, ncols=4)
fig.tight_layout() # Or equivalently,  "plt.tight_layout()"

plt.show()

Without Tight Layout

enter image description here


With Tight Layout enter image description here

Convert object of any type to JObject with Json.NET

If you have an object and wish to become JObject you can use:

JObject o = (JObject)JToken.FromObject(miObjetoEspecial);

like this :

Pocion pocionDeVida = new Pocion{
tipo = "vida",
duracion = 32,
};

JObject o = (JObject)JToken.FromObject(pocionDeVida);
Console.WriteLine(o.ToString());
// {"tipo": "vida", "duracion": 32,}

Changing Fonts Size in Matlab Plots

It's possible to change default fonts, both for the axes and for other text, by adding the following lines to the startup.m file.

% Change default axes fonts.
set(0,'DefaultAxesFontName', 'Times New Roman')
set(0,'DefaultAxesFontSize', 14)

% Change default text fonts.
set(0,'DefaultTextFontname', 'Times New Roman')
set(0,'DefaultTextFontSize', 14)

If you don't know if you have a startup.m file, run

which startup

to find its location. If Matlab says there isn't one, run

userpath

to know where it should be placed.

Get an object attribute

If you need to fetch an object's property dynamically, use the getattr() function: getattr(user, "fullName") - or to elaborate:

user = User()
property = "fullName"
name = getattr(user, property)

Otherwise just use user.fullName.

Which mime type should I use for mp3

The standard way is to use audio/mpeg which is something like this in your PHP header function ...

header('Content-Type: audio/mpeg');

ASP.NET MVC - passing parameters to the controller

Your routing needs to be set up along the lines of {controller}/{action}/{firstItem}. If you left the routing as the default {controller}/{action}/{id} in your global.asax.cs file, then you will need to pass in id.

routes.MapRoute(
    "Inventory",
    "Inventory/{action}/{firstItem}",
    new { controller = "Inventory", action = "ListAll", firstItem = "" }
);

... or something close to that.

Interface type check with Typescript

I found an example from @progress/kendo-data-query in file filter-descriptor.interface.d.ts

Checker

declare const isCompositeFilterDescriptor: (source: FilterDescriptor | CompositeFilterDescriptor) => source is CompositeFilterDescriptor;

Example usage

const filters: Array<FilterDescriptor | CompositeFilterDescriptor> = filter.filters;

filters.forEach((element: FilterDescriptor | CompositeFilterDescriptor) => {
    if (isCompositeFilterDescriptor(element)) {
        // element type is CompositeFilterDescriptor
    } else {
        // element type is FilterDescriptor
    }
});

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

The speed cannot be controlled by the API. Though you can modify CSS that is in charge of that. In the carousel.less file find

.item {
    display: none;
    position: relative;
    .transition(.6s ease-in-out left);
}

and change .6s to whatever you want.


In case you do not use .less, find in the bootstrap.css file:

.carousel-inner > .item {
    position: relative;
    display: none;
    -webkit-transition: 0.6s ease-in-out left;
    -moz-transition: 0.6s ease-in-out left;
    -o-transition: 0.6s ease-in-out left;
    transition: 0.6s ease-in-out left;
}

and change 0.6s to the time you want. You also might want to edit time in the function call below:

.emulateTransitionEnd(2000) 

at bootstrap.js in function Carousel.prototype.slide. That synchronize transition and prevent slide to disapear before transition ends.

EDIT 7/8/2014

As @YellowShark pointed out the edits in JS are not needed anymore. Only apply css changes.

EDIT 20/8/2015 Now, after you edit your css file, you just need to edit CAROUSEL.TRANSITION_DURATION (in bootstrap.js) or c.TRANSITION_DURATION (if you use bootstrap.min.js) and to change the value inside it (600 for default). The final value must be the same that you put in your css file( for example 10s in css = 10000 in .js)

EDIT 16/01/2018 For Bootstrap 4, to change the transition time to e.g., 2 seconds, add

$(document).ready(function() {
  jQuery.fn.carousel.Constructor.TRANSITION_DURATION = 2000  // 2 seconds
});

to your site's JS file, and

.carousel-inner .carousel-item {
  transition: -webkit-transform 2s ease;
  transition: transform 2s ease;
  transition: transform 2s ease, -webkit-transform 2s ease;
}

to your site's CSS file.

How to enter command with password for git pull?

This is not exactly what you asked for, but for http(s):

  • you can put the password in .netrc file (_netrc on windows). From there it would be picked up automatically. It would go to your home folder with 600 permissions.
  • you could also just clone the repo with https://user:pass@domain/repo but that's not really recommended as it would show your user/pass in a lot of places...
  • a new option is to use the credential helper. Note that credentials would be stored in clear text in your local config using standard credential helper. credential-helper with wincred can be also used on windows.

Usage examples for credential helper

  • git config credential.helper store - stores the credentials indefinitely.
  • git config credential.helper 'cache --timeout=3600'- stores for 60 minutes

For ssh-based access, you'd use ssh agent that will provide the ssh key when needed. This would require generating keys on your computer, storing the public key on the remote server and adding the private key to relevant keystore.

What is the difference between a .cpp file and a .h file?

By convention, .h files are included by other files, and never compiled directly by themselves. .cpp files are - again, by convention - the roots of the compilation process; they include .h files directly or indirectly, but generally not .cpp files.

What is an .axd file?

An AXD file is a file used by ASP.NET applications for handling embedded resource requests. It contains instructions for retrieving embedded resources, such as images, JavaScript (.JS) files, and.CSS files. AXD files are used for injecting resources into the client-side webpage and access them on the server in a standard way.

SQL - How to find the highest number in a column?

You can do

SELECT MAX(ID) FROM Customers;

How to determine if .NET Core is installed

On windows, You only need to open the command prompt and type:

dotnet --version

If the .net core framework installed you will get current installed version

see screenshot:

enter image description here

How can I show three columns per row?

This may be what you are looking for:

http://jsfiddle.net/L4L67/

_x000D_
_x000D_
body>div {_x000D_
  background: #aaa;_x000D_
  display: flex;_x000D_
  flex-wrap: wrap;_x000D_
}_x000D_
_x000D_
body>div>div {_x000D_
  flex-grow: 1;_x000D_
  width: 33%;_x000D_
  height: 100px;_x000D_
}_x000D_
_x000D_
body>div>div:nth-child(even) {_x000D_
  background: #23a;_x000D_
}_x000D_
_x000D_
body>div>div:nth-child(odd) {_x000D_
  background: #49b;_x000D_
}
_x000D_
<div>_x000D_
  <div></div>_x000D_
  <div></div>_x000D_
  <div></div>_x000D_
  <div></div>_x000D_
  <div></div>_x000D_
  <div></div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

jquery-ui-dialog - How to hook into dialog close event

I have found it!

You can catch the close event using the following code:

 $('div#popup_content').on('dialogclose', function(event) {
     alert('closed');
 });

Obviously I can replace the alert with whatever I need to do.
Edit: As of Jquery 1.7, the bind() has become on()

How to add multiple font files for the same font?

nowadays,2017-12-17. I don't find any description about Font-property-order‘s necessity in spec. And I test in chrome always works whatever the order is.

@font-face {
  font-family: 'Font Awesome 5 Free';
  font-weight: 900;
  src: url('#{$fa-font-path}/fa-solid-900.eot');
  src: url('#{$fa-font-path}/fa-solid-900.eot?#iefix') format('embedded-opentype'),
  url('#{$fa-font-path}/fa-solid-900.woff2') format('woff2'),
  url('#{$fa-font-path}/fa-solid-900.woff') format('woff'),
  url('#{$fa-font-path}/fa-solid-900.ttf') format('truetype'),
  url('#{$fa-font-path}/fa-solid-900.svg#fontawesome') format('svg');
}

@font-face {
  font-family: 'Font Awesome 5 Free';
  font-weight: 400;
  src: url('#{$fa-font-path}/fa-regular-400.eot');
  src: url('#{$fa-font-path}/fa-regular-400.eot?#iefix') format('embedded-opentype'),
  url('#{$fa-font-path}/fa-regular-400.woff2') format('woff2'),
  url('#{$fa-font-path}/fa-regular-400.woff') format('woff'),
  url('#{$fa-font-path}/fa-regular-400.ttf') format('truetype'),
  url('#{$fa-font-path}/fa-regular-400.svg#fontawesome') format('svg');
}

Controller 'ngModel', required by directive '...', can't be found

One possible solution to this issue is ng-model attribute is required to use that directive.

Hence adding in the 'ng-model' attribute can resolve the issue.

<input submit-required="true" ng-model="user.Name"></input>

How do I specify the platform for MSBuild?

When you define different build configurations in your visual studio solution for your projects using a tool like ConfigurationTransform, you may want your Teamcity build, to build you a specified build configuration. You may have build configurations e.g., Debug, Release, Dev, UAT, Prod etc defined. This means, you will have MSBuild Configuration transformation setup for the different configurations. These different configurations are usually used when you have different configurations, e.g. different database connection strings, for the different environment. This is very common because you would have a different database for your production environment from your playground development environment.

They say a picture is worth a thousand words, please see the image below how you would specify multiple build configurations in Teamcity.

In the commandline input text box, specify as below

/p:OutputPath=Publish;Configuration=Dev

Here, I have specified two commandline build configurations/arguments OutputPath and build Configuration with values Publish and Dev respectively, but it could have been, UAT or Prod configuration. If you want more, simply separate them by semi-colon,;

Teamcity MSBuild Commandline build configuration screenshot

How to pass form input value to php function

You need to look into Ajax; Start here this is the best way to stay on the current page and be able to send inputs to php.

<!DOCTYPE html>
<html>
<head>
<script>
function showHint(str)
{
var xmlhttp;
if (str.length==0)
  { 
  document.getElementById("txtHint").innerHTML="";
  return;
  }
if (window.XMLHttpRequest)
  {// code for IE7+, Firefox, Chrome, Opera, Safari
  xmlhttp=new XMLHttpRequest();
  }
else
  {// code for IE6, IE5
  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
  }
xmlhttp.onreadystatechange=function()
  {
  if (xmlhttp.readyState==4 && xmlhttp.status==200)
    {
    document.getElementById("txtHint").innerHTML=xmlhttp.responseText;
    }
  }
xmlhttp.open("GET","gethint.php?q="+str,true);
xmlhttp.send();
}
</script>
</head>
<body>

<h3>Start typing a name in the input field below:</h3>
<form action=""> 
First name: <input type="text" id="txt1" onkeyup="showHint(this.value)" />
</form>
<p>Suggestions: <span id="txtHint"></span></p> 

</body>
</html>

This gets the users input on the textbox and opens the webpage gethint.php?q=ja from here the php script can do anything with $_GET['q'] and echo back to the page James, Jason....etc

Mixing a PHP variable with a string literal

echo "{$test}y";

You can use braces to remove ambiguity when interpolating variables directly in strings.

Also, this doesn't work with single quotes. So:

echo '{$test}y';

will output

{$test}y

How to remove the first character of string in PHP?

Exec time for the 3 answers :

Remove the first letter by replacing the case

$str = "hello";
$str[0] = "";
// $str[0] = false;
// $str[0] = null;
// replaced by ?, but ok for echo

Exec time for 1.000.000 tests : 0.39602184295654 sec


Remove the first letter with substr()

$str = "hello";
$str = substr($str, 1);

Exec time for 1.000.000 tests : 5.153294801712 sec


Remove the first letter with ltrim()

$str = "hello";
$str= ltrim ($str,'h');

Exec time for 1.000.000 tests : 5.2393000125885 sec


Remove the first letter with preg_replace()

$str = "hello";
$str = preg_replace('/^./', '', $str);

Exec time for 1.000.000 tests : 6.8543920516968 sec

Difference between Visibility.Collapsed and Visibility.Hidden

The difference is that Visibility.Hidden hides the control, but reserves the space it occupies in the layout. So it renders whitespace instead of the control. Visibilty.Collapsed does not render the control and does not reserve the whitespace. The space the control would take is 'collapsed', hence the name.

The exact text from the MSDN:

Collapsed: Do not display the element, and do not reserve space for it in layout.

Hidden: Do not display the element, but reserve space for the element in layout.

Visible: Display the element.

See: http://msdn.microsoft.com/en-us/library/system.windows.visibility.aspx

How to determine when a Git branch was created?

This did it for me: (10 years later)

git log [--remotes] --no-walk --decorate

Since there is no stored information on branch creation times, what this does is display the first commit of each branch (--no-walk), which includes the date of the commit. Use --remotes for the remote branches, or omit it for local branches.

Since I do at least one commit in a branch before creating another one, this permitted me trace back a few months of branch creations (and feature dev-start) for documentation purposes.

source: AnoE on stackexchange

How can I strip all punctuation from a string in JavaScript using regex?

If you want to retain only alphabets and spaces, you can do:

str.replace(/[^a-zA-Z ]+/g, '').replace('/ {2,}/',' ')

Why does JavaScript only work after opening developer tools in IE once?

We ran into this problem on IE 11 on Windows 7 and Windows 10. We discovered what exactly the problem was by turning on debugging capabilities for IE (IE > Internet Options > Advanced tab > Browsing > Uncheck Disable script debugging (Internet Explorer)). This feature is typically checked on within our environment by the domain admins.

The problem was because we were using the console.debug(...) method within our JavaScript code. The assumption made by the developer (me) was I did not want anything written if the client Developer Tools console was not explicitly open. While Chrome and Firefox seemed to agree with this strategy, IE 11 did not like it one bit. By changing all the console.debug(...) statements to console.log(...) statements, we were able to continue to log additional information in the client console and view it when it was open, but otherwise keep it hidden from the typical user.

PHP-FPM and Nginx: 502 Bad Gateway

I'm very late to this game, but my problem started when I upgraded php on my server. I was able to just remove the .socket file and restart my services. Then, everything worked. Not sure why it made a difference, since the file is size 0 and the ownership and permissions are the same, but it worked.

How do I initialize a byte array in Java?

As far as a clean process is concerned you can use ByteArrayOutputStream object...

ByteArrayOutputStream bObj = new ByteArrayOutputStream();
bObj.reset();

//write all the values to bObj one by one using

bObj.write(byte value)

// when done you can get the byte[] using

CDRIVES = bObj.toByteArray();

//than you can repeat the similar process for CMYDOCS and IEFRAME as well,

NOTE This is not an efficient solution if you really have small array.

How do I check whether input string contains any spaces?

To check if a string does not contain any whitespaces, you can use

string.matches("^\\S*$")

Example:

"name"        -> true
"  "          -> false
"name xxname" -> false

Does Java support default parameter values?

A similar approach to https://stackoverflow.com/a/13864910/2323964 that works in Java 8 is to use an interface with default getters. This will be more whitespace verbose, but is mockable, and it's great for when you have a bunch of instances where you actually want to draw attention to the parameters.

public class Foo() {
    public interface Parameters {
        String getRequired();
        default int getOptionalInt(){ return 23; }
        default String getOptionalString(){ return "Skidoo"; }
    }

    public Foo(Parameters parameters){
        //...
    }

    public static void baz() {
        final Foo foo = new Foo(new Person() {
            @Override public String getRequired(){ return "blahblahblah"; }
            @Override public int getOptionalInt(){ return 43; }
        });
    }
}

Execute a shell function with timeout

As Douglas Leeder said you need a separate process for timeout to signal to. Workaround by exporting function to subshells and running subshell manually.

export -f echoFooBar
timeout 10s bash -c echoFooBar

Write lines of text to a file in R

Based on the best answer:

file <- file("test.txt")
writeLines(yourObject, file)
close(file)

Note that the yourObject needs to be in a string format; use as.character() to convert if you need.

But this is too much typing for every save attempt. Let's create a snippet in RStudio.

In Global Options >> Code >> Snippet, type this:

snippet wfile
    file <- file(${1:filename})
    writeLines(${2:yourObject}, file)
    close(file)

Then, during coding, type wfile and press Tab.

Node.js setting up environment specific configs to be used with everyauth

My solution,

load the app using

NODE_ENV=production node app.js

Then setup config.js as a function rather than an object

module.exports = function(){
    switch(process.env.NODE_ENV){
        case 'development':
            return {dev setting};

        case 'production':
            return {prod settings};

        default:
            return {error or other settings};
    }
};

Then as per Jans solution load the file and create a new instance which we could pass in a value if needed, in this case process.env.NODE_ENV is global so not needed.

var Config = require('./conf'),
    conf = new Config();

Then we can access the config object properties exactly as before

conf.twitter.consumerKey

How can I solve the error LNK2019: unresolved external symbol - function?

Since I want my project to compile to a stand-alone EXE file, I linked the UnitTest project to the function.obj file generated from function.cpp and it works.

Right click on the 'UnitTest1' project ? Configuration Properties ? Linker ? Input ? Additional Dependencies ? add "..\MyProjectTest\Debug\function.obj".

ASP.net Getting the error "Access to the path is denied." while trying to upload files to my Windows Server 2008 R2 Web server

Right click on your folder on your server or local machine and give full permissions to

IIS_IUSRS

that's it.

How to check if a textbox is empty using javascript

Canonical without using frameworks with added trim prototype for older browsers

<html>
<head>
<script type="text/javascript">
// add trim to older IEs
if (!String.trim) {
  String.prototype.trim = function() {return this.replace(/^\s+|\s+$/g, "");};
}

window.onload=function() { // onobtrusively adding the submit handler
  document.getElementById("form1").onsubmit=function() { // needs an ID
    var val = this.textField1.value; // 'this' is the form 
    if (val==null || val.trim()=="") { 
      alert('Please enter something');
      this.textField1.focus();
      return false; // cancel submission
    }
    return true; // allow submit
  }
}
</script>
</head>
<body>
<form id="form1">
  <input type="text" name="textField1" value="" /><br/>
  <input type="submit" />
</form>
</body>
</html>

Here is the inline version, although not recommended I show it here in case you need to add validation without being able to refactor the code

function validate(theForm) { // passing the form object
  var val = theForm.textField1.value;
  if (val==null || val.trim()=="") { 
    alert('Please enter something');
    theForm.textField1.focus();
    return false; // cancel submission
  }
  return true; // allow submit
}

passing the form object in (this)

<form onsubmit="return validate(this)">
  <input type="text" name="textField1" value="" /><br/>
  <input type="submit" />
</form>

What throws an IOException in Java?

In general, I/O means Input or Output. Those methods throw the IOException whenever an input or output operation is failed or interpreted. Note that this won't be thrown for reading or writing to memory as Java will be handling it automatically.

Here are some cases which result in IOException.

  • Reading from a closed inputstream
  • Try to access a file on the Internet without a network connection

How do I split a string in Rust?

There is a special method split for struct String:

fn split<'a, P>(&'a self, pat: P) -> Split<'a, P> where P: Pattern<'a>

Split by char:

let v: Vec<&str> = "Mary had a little lamb".split(' ').collect();
assert_eq!(v, ["Mary", "had", "a", "little", "lamb"]);

Split by string:

let v: Vec<&str> = "lion::tiger::leopard".split("::").collect();
assert_eq!(v, ["lion", "tiger", "leopard"]);

Split by closure:

let v: Vec<&str> = "abc1def2ghi".split(|c: char| c.is_numeric()).collect();
assert_eq!(v, ["abc", "def", "ghi"]);

C++ catching all exceptions

You can use

catch(...)

but that is very dangerous. In his book Debugging Windows, John Robbins tells a war story about a really nasty bug that was masked by a catch(...) command. You're much better off catching specific exceptions. Catch whatever you think your try block might reasonably throw, but let the code throw an exception higher up if something really unexpected happens.

Scrolling a div with jQuery

jCarousel is a Jquery Plugin , it have same functionality already implemented , which might want to archive. it's nice and easy. here is the link

and complete documentation can be found here

How to output to the console and file?

Probably the shortest solution:

def printLog(*args, **kwargs):
    print(*args, **kwargs)
    with open('output.out','a') as file:
        print(*args, **kwargs, file=file)

printLog('hello world')

Writes 'hello world' to sys.stdout and to output.out and works exactly the same way as print().

Note: Please do not specify the file argument for the printLog function. Calls like printLog('test',file='output2.out') are not supported.

Changing the interval of SetInterval while it's running

I couldn't synchronize and change the speed my setIntervals too and I was about to post a question. But I think I've found a way. It should certainly be improved because I'm a beginner. So, I'd gladly read your comments/remarks about this.

<body onload="foo()">
<div id="count1">0</div>
<div id="count2">2nd counter is stopped</div>
<button onclick="speed0()">pause</button>
<button onclick="speedx(1)">normal speed</button>
<button onclick="speedx(2)">speed x2</button>
<button onclick="speedx(4)">speed x4</button>
<button onclick="startTimer2()">Start second timer</button>
</body>
<script>
var count1 = 0,
    count2 = 0,
    greenlight = new Boolean(0), //blocks 2nd counter
    speed = 1000,   //1second
    countingSpeed;
function foo(){
    countingSpeed = setInterval(function(){
        counter1();
        counter2();
    },speed);
}
function counter1(){
    count1++;
    document.getElementById("count1").innerHTML=count1;
}
function counter2(){
    if (greenlight != false) {
        count2++;
        document.getElementById("count2").innerHTML=count2;
    }
}
function startTimer2(){
    //while the button hasn't been clicked, greenlight boolean is false
    //thus, the 2nd timer is blocked
    greenlight = true;
    counter2();
    //counter2() is greenlighted
}

//these functions modify the speed of the counters
function speed0(){
    clearInterval(countingSpeed);
}
function speedx(a){
    clearInterval(countingSpeed);
    speed=1000/a;
    foo();
}
</script>

If you want the counters to begin to increase once the page is loaded, put counter1() and counter2() in foo() before countingSpeed is called. Otherwise, it takes speed milliseconds before execution. EDIT : Shorter answer.

Confused by python file mode "w+"

Both seems to be working same but there is a catch.

r+ :-

  • Open the file for Reading and Writing
  • Once Opened in the beginning file pointer will point to 0
  • Now if you will want to Read then it will start reading from beginning
  • if you want to Write then start writing, But the write process will begin from pointer 0. So there would be overwrite of characters, if there is any
  • In this case File should be present, either will FileNotFoundError will be raised.

w+ :-

  • Open the file for Reading and Writing
  • If file exist, File will be opened and all data will be erased,
  • If file does not exist, then new file will be created
  • In the beginning file pointer will point to 0 (as there is not data)
  • Now if you want to write something, then write
  • File pointer will be Now pointing to end of file (after write process)
  • If you want to read the data now, seek to specific point. (for beginning seek(0))

So, Overall saying both are meant to open the file to read and write but difference is whether we want to erase the data in the beginning and then do read/write or just start as it is.

abc.txt - in beginning

1234567
abcdefg
0987654
1234

Code for r+

with open('abc.txt', 'r+') as f:      # abc.txt should exist before opening
    print(f.tell())                   # Should give ==> 0
    f.write('abcd')                   
    print(f.read())                   # Pointer is pointing to index 3 => 4th position
    f.write('Sunny')                  # After read pointer is at End of file

Output

0
567
abcdefg
0987654
1234

abc.txt - After Run:

abcd567
abcdefg
0987654
1234Sunny

Resetting abc.txt as initial

Code for w+

with open('abc.txt', 'w+') as f:     
    print(f.tell())                   # Should give ==> 0
    f.write('abcd')                   
    print(f.read())                   # Pointer is pointing to index 3 => 4th position
    f.write('Sunny')                  # After read pointer is at End of file

Output

0


abc.txt - After Run:

abcdSunny

unable to start mongodb local server

try

/usr/lib/mongodb/mongod.exe --dbpath c:data\db

--dbpath (should be followed by the path of your db)

Windows equivalent to UNIX pwd

You can simply put "." the dot sign. I've had a cmd application that was requiring the path and I was already in the needed directory and I used the dot symbol.

Hope it helps.

How do I get formatted JSON in .NET using C#?

You may use following standard method for getting formatted Json

JsonReaderWriterFactory.CreateJsonWriter(Stream stream, Encoding encoding, bool ownsStream, bool indent, string indentChars)

Only set "indent==true"

Try something like this

    public readonly DataContractJsonSerializerSettings Settings = 
            new DataContractJsonSerializerSettings
            { UseSimpleDictionaryFormat = true };

    public void Keep<TValue>(TValue item, string path)
    {
        try
        {
            using (var stream = File.Open(path, FileMode.Create))
            {
                //var currentCulture = Thread.CurrentThread.CurrentCulture;
                //Thread.CurrentThread.CurrentCulture = CultureInfo.InvariantCulture;

                try
                {
                    using (var writer = JsonReaderWriterFactory.CreateJsonWriter(
                        stream, Encoding.UTF8, true, true, "  "))
                    {
                        var serializer = new DataContractJsonSerializer(type, Settings);
                        serializer.WriteObject(writer, item);
                        writer.Flush();
                    }
                }
                catch (Exception exception)
                {
                    Debug.WriteLine(exception.ToString());
                }
                finally
                {
                    //Thread.CurrentThread.CurrentCulture = currentCulture;
                }
            }
        }
        catch (Exception exception)
        {
            Debug.WriteLine(exception.ToString());
        }
    }

Pay your attention to lines

    var currentCulture = Thread.CurrentThread.CurrentCulture;
    Thread.CurrentThread.CurrentCulture = CultureInfo.InvariantCulture;
    ....
    Thread.CurrentThread.CurrentCulture = currentCulture;

For some kinds of xml-serializers you should use InvariantCulture to avoid exception during deserialization on the computers with different Regional settings. For example, invalid format of double or DateTime sometimes cause them.

For deserializing

    public TValue Revive<TValue>(string path, params object[] constructorArgs)
    {
        try
        {
            using (var stream = File.OpenRead(path))
            {
                //var currentCulture = Thread.CurrentThread.CurrentCulture;
                //Thread.CurrentThread.CurrentCulture = CultureInfo.InvariantCulture;

                try
                {
                    var serializer = new DataContractJsonSerializer(type, Settings);
                    var item = (TValue) serializer.ReadObject(stream);
                    if (Equals(item, null)) throw new Exception();
                    return item;
                }
                catch (Exception exception)
                {
                    Debug.WriteLine(exception.ToString());
                    return (TValue) Activator.CreateInstance(type, constructorArgs);
                }
                finally
                {
                    //Thread.CurrentThread.CurrentCulture = currentCulture;
                }
            }
        }
        catch
        {
            return (TValue) Activator.CreateInstance(typeof (TValue), constructorArgs);
        }
    }

Thanks!

Java get last element of a collection

To avoid some of the problems mentioned above (not robust for nulls etc etc), to get first and last element in a list an approach could be

import java.util.List;

public static final <A> A getLastElement(List<A> list) {
    return list != null ? getElement(list, list.size() - 1) : null;
}

public static final <A> A getFirstElement(List<A> list) {
    return list != null ? getElement(list, 0) : null;
}   

private static final <A> A getElement(List<A> list, int pointer) {
    A res = null;
    if (list.size() > 0) {
        res = list.get(pointer);            
    }
    return res;
}

The convention adopted is that the first/last element of an empty list is null...

Characters allowed in a URL

These are listed in RFC3986. See the Collected ABNF for URI to see what is allowed where and the regex for parsing/validation.

How to check if a database exists in SQL Server?

TRY THIS

IF EXISTS 
   (
     SELECT name FROM master.dbo.sysdatabases 
    WHERE name = N'New_Database'
    )
BEGIN
    SELECT 'Database Name already Exist' AS Message
END
ELSE
BEGIN
    CREATE DATABASE [New_Database]
    SELECT 'New Database is Created'
END

How do I remove packages installed with Python's easy_install?

There are several sources on the net suggesting a hack by reinstalling the package with the -m option and then just removing the .egg file in lib/ and the binaries in bin/. Also, discussion about this setuptools issue can be found on the python bug tracker as setuptools issue 21.

Edit: Added the link to the python bugtracker.

Is it possible to write data to file using only JavaScript?

Above answer is useful but, I found code which helps you to download text file directly on button click. In this code you can also change filename as you wish. It's pure javascript function with HTML5. Works for me!

function saveTextAsFile()
{
    var textToWrite = document.getElementById("inputTextToSave").value;
    var textFileAsBlob = new Blob([textToWrite], {type:'text/plain'});
    var fileNameToSaveAs = document.getElementById("inputFileNameToSaveAs").value;
      var downloadLink = document.createElement("a");
    downloadLink.download = fileNameToSaveAs;
    downloadLink.innerHTML = "Download File";
    if (window.webkitURL != null)
    {
        // Chrome allows the link to be clicked
        // without actually adding it to the DOM.
        downloadLink.href = window.webkitURL.createObjectURL(textFileAsBlob);
    }
    else
    {
        // Firefox requires the link to be added to the DOM
        // before it can be clicked.
        downloadLink.href = window.URL.createObjectURL(textFileAsBlob);
        downloadLink.onclick = destroyClickedElement;
        downloadLink.style.display = "none";
        document.body.appendChild(downloadLink);
    }

    downloadLink.click();
}

Docker error: invalid reference format: repository name must be lowercase

In my case, the image name defined in docker-compose.yml contained uppercase letters. The fact that the error message mentioned repository instead of image did not help describe the problem and it took a while to figure out.

Checking whether the pip is installed?

You need to run pip list in bash not in python.

pip list
DEPRECATION: Python 2.6 is no longer supported by the Python core team, please upgrade your Python. A future version of pip will drop support for Python 2.6
argparse (1.4.0)
Beaker (1.3.1)
cas (0.15)
cups (1.0)
cupshelpers (1.0)
decorator (3.0.1)
distribute (0.6.10)
---and other modules

Clearing all cookies with JavaScript

An answer influenced by both second answer here and W3Schools

document.cookie.split(';').forEach(function(c) {
  document.cookie = c.trim().split('=')[0] + '=;' + 'expires=Thu, 01 Jan 1970 00:00:00 UTC;';
});

Seems to be working

edit: wow almost exactly the same as Zach's interesting how Stack Overflow put them next to each other.

edit: nvm that was temporary apparently

what is Segmentation fault (core dumped)?

"Segmentation fault" means that you tried to access memory that you do not have access to.

The first problem is with your arguments of main. The main function should be int main(int argc, char *argv[]), and you should check that argc is at least 2 before accessing argv[1].

Also, since you're passing in a float to printf (which, by the way, gets converted to a double when passing to printf), you should use the %f format specifier. The %s format specifier is for strings ('\0'-terminated character arrays).

open a url on click of ok button in android

On Button click event write this:

Uri uri = Uri.parse("http://www.google.com"); // missing 'http://' will cause crashed
Intent intent = new Intent(Intent.ACTION_VIEW, uri);
startActivity(intent);

that open the your URL.

Is there a Python caching library?

From Python 3.2 you can use the decorator @lru_cache from the functools library. It's a Last Recently Used cache, so there is no expiration time for the items in it, but as a fast hack it's very useful.

from functools import lru_cache

@lru_cache(maxsize=256)
def f(x):
  return x*x

for x in range(20):
  print f(x)
for x in range(20):
  print f(x)

Update Tkinter Label from variable

Maybe I'm not understanding the question but here is my simple solution that works -

# I want to Display total heads bent this machine so I define a label -
TotalHeadsLabel3 = Label(leftFrame)
TotalHeadsLabel3.config(font=Helv12,fg='blue',text="Total heads " + str(TotalHeads))
TotalHeadsLabel3.pack(side=TOP)

# I update the int variable adding the quantity bent -
TotalHeads = TotalHeads + headQtyBent # update ready to write to file & display
TotalHeadsLabel3.config(text="Total Heads "+str(TotalHeads)) # update label with new qty

I agree that labels are not automatically updated but can easily be updated with the

<label name>.config(text="<new text>" + str(<variable name>))

That just needs to be included in your code after the variable is updated.

JOIN queries vs multiple queries

There are several factors which means there is no binary answer. The question of what is best for performance depends on your environment. By the way, if your single select with an identifier is not sub-second, something may be wrong with your configuration.

The real question to ask is how do you want to access the data. Single selects support late-binding. For example if you only want employee information, you can select from the Employees table. The foreign key relationships can be used to retrieve related resources at a later time and as needed. The selects will already have a key to point to so they should be extremely fast, and you only have to retrieve what you need. Network latency must always be taken into account.

Joins will retrieve all of the data at once. If you are generating a report or populating a grid, this may be exactly what you want. Compiled and optomized joins are simply going to be faster than single selects in this scenario. Remember, Ad-hoc joins may not be as fast--you should compile them (into a stored proc). The speed answer depends on the execution plan, which details exactly what steps the DBMS takes to retrieve the data.

Updating an object with setState in React

You can try with this:

this.setState(prevState => {
   prevState = JSON.parse(JSON.stringify(this.state.jasper));
   prevState.name = 'someOtherName';
   return {jasper: prevState}
})

or for other property:

this.setState(prevState => {
   prevState = JSON.parse(JSON.stringify(this.state.jasper));
   prevState.age = 'someOtherAge';
   return {jasper: prevState}
})

Or you can use handleChage function:

handleChage(event) {
   const {name, value} = event.target;
    this.setState(prevState => {
       prevState = JSON.parse(JSON.stringify(this.state.jasper));
       prevState[name] = value;
       return {jasper: prevState}
    })
}

and HTML code:

<input 
   type={"text"} 
   name={"name"} 
   value={this.state.jasper.name} 
   onChange={this.handleChange}
/>
<br/>
<input 
   type={"text"} 
   name={"age"} 
   value={this.state.jasper.age} 
   onChange={this.handleChange}
/>

How to Lock/Unlock screen programmatically?

The androidmanifest.xml and policies.xml files on the sample page are invisible in my browser due to it trying to format the XML files as HTML. I'm only posting this for reference for the convenience of others, this is sourced from the sample page.

Thanks all for this helpful question!

AndroidManifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.kns"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-sdk android:minSdkVersion="8" />

    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".LockScreenActivity"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <receiver android:name=".MyAdmin"
                android:permission="android.permission.BIND_DEVICE_ADMIN">
            <meta-data android:name="android.app.device_admin"
                       android:resource="@xml/policies" />
            <intent-filter>
                <action android:name="android.app.action.DEVICE_ADMIN_ENABLED" />
            </intent-filter>
        </receiver>

    </application>
</manifest>

policies.xml

<?xml version="1.0" encoding="utf-8"?>
<device-admin xmlns:android="http://schemas.android.com/apk/res/android">
    <uses-policies>
        <limit-password />
        <watch-login />
        <reset-password />
        <force-lock />
        <wipe-data />
    </uses-policies>
</device-admin>

how to pass parameters to query in SQL (Excel)

This post is old enough that this answer will probably be little use to the OP, but I spent forever trying to answer this same question, so I thought I would update it with my findings.

This answer assumes that you already have a working SQL query in place in your Excel document. There are plenty of tutorials to show you how to accomplish this on the web, and plenty that explain how to add a parameterized query to one, except that none seem to work for an existing, OLE DB query.

So, if you, like me, got handed a legacy Excel document with a working query, but the user wants to be able to filter the results based on one of the database fields, and if you, like me, are neither an Excel nor a SQL guru, this might be able to help you out.

Most web responses to this question seem to say that you should add a “?” in your query to get Excel to prompt you for a custom parameter, or place the prompt or the cell reference in [brackets] where the parameter should be. This may work for an ODBC query, but it does not seem to work for an OLE DB, returning “No value given for one or more required parameters” in the former instance, and “Invalid column name ‘xxxx’” or “Unknown object ‘xxxx’” in the latter two. Similarly, using the mythical “Parameters…” or “Edit Query…” buttons is also not an option as they seem to be permanently greyed out in this instance. (For reference, I am using Excel 2010, but with an Excel 97-2003 Workbook (*.xls))

What we can do, however, is add a parameter cell and a button with a simple routine to programmatically update our query text.

First, add a row above your external data table (or wherever) where you can put a parameter prompt next to an empty cell and a button (Developer->Insert->Button (Form Control) – You may need to enable the Developer tab, but you can find out how to do that elsewhere), like so:

[Picture of a cell of prompt (label) text, an empty cell, then a button.]

Next, select a cell in the External Data (blue) area, then open Data->Refresh All (dropdown)->Connection Properties… to look at your query. The code in the next section assumes that you already have a parameter in your query (Connection Properties->Definition->Command Text) in the form “WHERE (DB_TABLE_NAME.Field_Name = ‘Default Query Parameter')” (including the parentheses). Clearly “DB_TABLE_NAME.Field_Name” and “Default Query Parameter” will need to be different in your code, based on the database table name, database value field (column) name, and some default value to search for when the document is opened (if you have auto-refresh set). Make note of the “DB_TABLE_NAME.Field_Name” value as you will need it in the next section, along with the “Connection name” of your query, which can be found at the top of the dialog.

Close the Connection Properties, and hit Alt+F11 to open the VBA editor. If you are not on it already, right click on the name of the sheet containing your button in the “Project” window, and select “View Code”. Paste the following code into the code window (copying is recommended, as the single/double quotes are dicey and necessary).

Sub RefreshQuery()
 Dim queryPreText As String
 Dim queryPostText As String
 Dim valueToFilter As String
 Dim paramPosition As Integer
 valueToFilter = "DB_TABLE_NAME.Field_Name ="

 With ActiveWorkbook.Connections("Connection name").OLEDBConnection
     queryPreText = .CommandText
     paramPosition = InStr(queryPreText, valueToFilter) + Len(valueToFilter) - 1
     queryPreText = Left(queryPreText, paramPosition)
     queryPostText = .CommandText
     queryPostText = Right(queryPostText, Len(queryPostText) - paramPosition)
     queryPostText = Right(queryPostText, Len(queryPostText) - InStr(queryPostText, ")") + 1)
     .CommandText = queryPreText & " '" & Range("Cell reference").Value & "'" & queryPostText
 End With
 ActiveWorkbook.Connections("Connection name").Refresh
End Sub

Replace “DB_TABLE_NAME.Field_Name” and "Connection name" (in two locations) with your values (the double quotes and the space and equals sign need to be included).

Replace "Cell reference" with the cell where your parameter will go (the empty cell from the beginning) - mine was the second cell in the first row, so I put “B1” (again, the double quotes are necessary).

Save and close the VBA editor.

Enter your parameter in the appropriate cell.

Right click your button to assign the RefreshQuery sub as the macro, then click your button. The query should update and display the right data!

Notes: Using the entire filter parameter name ("DB_TABLE_NAME.Field_Name =") is only necessary if you have joins or other occurrences of equals signs in your query, otherwise just an equals sign would be sufficient, and the Len() calculation would be superfluous. If your parameter is contained in a field that is also being used to join tables, you will need to change the "paramPosition = InStr(queryPreText, valueToFilter) + Len(valueToFilter) - 1" line in the code to "paramPosition = InStr(Right(.CommandText, Len(.CommandText) - InStrRev(.CommandText, "WHERE")), valueToFilter) + Len(valueToFilter) - 1 + InStr(.CommandText, "WHERE")" so that it only looks for the valueToFilter after the "WHERE".

This answer was created with the aid of datapig’s “BaconBits” where I found the base code for the query update.

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

Here is an awesome and precise explanation I found.

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

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

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

TIMESTAMP is 4 bytes and DATETIME is 8 bytes.

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

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

Also...

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

Search input with an icon Bootstrap 4

I made another variant with dropdown menu (perhaps for advanced search etc).. Here is how it looks like:

Bootstrap 4 searh bar with dropdown menu

<div class="input-group my-4 col-6 mx-auto">
    <input class="form-control py-2 border-right-0 border" type="search" placeholder="Type something..." id="example-search-input">
    <span class="input-group-append">
        <button type="button" class="btn btn-outline-primary dropdown-toggle dropdown-toggle-split border border-left-0 border-right-0 rounded-0" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
            <span class="sr-only">Toggle Dropdown</span>
        </button>
        <button class="btn btn-outline-primary rounded-right" type="button">
            <i class="fas fa-search"></i>
        </button>
        <div class="dropdown-menu dropdown-menu-right">
            <a class="dropdown-item" href="#">Action</a>
            <a class="dropdown-item" href="#">Another action</a>
            <a class="dropdown-item" href="#">Something else here</a>
            <div role="separator" class="dropdown-divider"></div>
            <a class="dropdown-item" href="#">Separated link</a>
        </div>
    </span>
</div>

Note: It appears green in the screenshot because my site main theme is green.

Checking for NULL pointer in C/C++

if (foo) is clear enough. Use it.

Can I run javascript before the whole page is loaded?

You can run javascript code at any time. AFAIK it is executed at the moment the browser reaches the <script> tag where it is in. But you cannot access elements that are not loaded yet.

So if you need access to elements, you should wait until the DOM is loaded (this does not mean the whole page is loaded, including images and stuff. It's only the structure of the document, which is loaded much earlier, so you usually won't notice a delay), using the DOMContentLoaded event or functions like $.ready in jQuery.

Terminating a Java Program

Calling System.exit(0) (or any other value for that matter) causes the Java virtual machine to exit, terminating the current process. The parameter you pass will be the return value that the java process will return to the operating system. You can make this call from anywhere in your program - and the result will always be the same - JVM terminates. As this is simply calling a static method in System class, the compiler does not know what it will do - and hence does not complain about unreachable code.

return statement simply aborts execution of the current method. It literally means return the control to the calling method. If the method is declared as void (as in your example), then you do not need to specify a value, as you'd need to return void. If the method is declared to return a particular type, then you must specify the value to return - and this value must be of the specified type.

return would cause the program to exit only if it's inside the main method of the main class being execute. If you try to put code after it, the compiler will complain about unreachable code, for example:

public static void main(String... str) {
    System.out.println(1);
    return;
    System.out.println(2);
    System.exit(0);
}

will not compile with most compiler - producing unreachable code error pointing to the second System.out.println call.

How can I use optional parameters in a T-SQL stored procedure?

You can do in the following case,

CREATE PROCEDURE spDoSearch
   @FirstName varchar(25) = null,
   @LastName varchar(25) = null,
   @Title varchar(25) = null
AS
  BEGIN
      SELECT ID, FirstName, LastName, Title
      FROM tblUsers
      WHERE
        (@FirstName IS NULL OR FirstName = @FirstName) AND
        (@LastNameName IS NULL OR LastName = @LastName) AND
        (@Title IS NULL OR Title = @Title)
END

however depend on data sometimes better create dynamic query and execute them.

How can I convert an MDB (Access) file to MySQL (or plain SQL file)?

I modified the script by Nicolay77 to output the database to stdout (the usual way of unix scripts) so that I could output the data to text file or pipe it to any program I want. The resulting script is a bit simpler and works well.

Some examples:

./mdb_to_mysql.sh database.mdb > data.sql

./mdb_to_mysql.sh database.mdb | mysql destination-db -u user -p

Here is the modified script (save to mdb_to_mysql.sh)

#!/bin/bash
TABLES=$(mdb-tables -1 $1)

for t in $TABLES
do
    echo "DROP TABLE IF EXISTS $t;"
done

mdb-schema $1 mysql

for t in $TABLES
do
    mdb-export -D '%Y-%m-%d %H:%M:%S' -I mysql $1 $t
done

Should I use Vagrant or Docker for creating an isolated environment?

I'm the author of Docker.

The short answer is that if you want to manage machines, you should use Vagrant. And if you want to build and run applications environments, you should use Docker.

Vagrant is a tool for managing virtual machines. Docker is a tool for building and deploying applications by packaging them into lightweight containers. A container can hold pretty much any software component along with its dependencies (executables, libraries, configuration files, etc.), and execute it in a guaranteed and repeatable runtime environment. This makes it very easy to build your app once and deploy it anywhere - on your laptop for testing, then on different servers for live deployment, etc.

It's a common misconception that you can only use Docker on Linux. That's incorrect; you can also install Docker on Mac, and Windows. When installed on Mac, Docker bundles a tiny Linux VM (25 MB on disk!) which acts as a wrapper for your container. Once installed this is completely transparent; you can use the Docker command-line in exactly the same way. This gives you the best of both worlds: you can test and develop your application using containers, which are very lightweight, easy to test and easy to move around (see for example https://hub.docker.com for sharing reusable containers with the Docker community), and you don't need to worry about the nitty-gritty details of managing virtual machines, which are just a means to an end anyway.

In theory it's possible to use Vagrant as an abstraction layer for Docker. I recommend against this for two reasons:

  • First, Vagrant is not a good abstraction for Docker. Vagrant was designed to manage virtual machines. Docker was designed to manage an application runtime. This means that Docker, by design, can interact with an application in richer ways, and has more information about the application runtime. The primitives in Docker are processes, log streams, environment variables, and network links between components. The primitives in Vagrant are machines, block devices, and ssh keys. Vagrant simply sits lower in the stack, and the only way it can interact with a container is by pretending it's just another kind of machine, that you can "boot" and "log into". So, sure, you can type "vagrant up" with a Docker plugin and something pretty will happen. Is it a substitute for the full breadth of what Docker can do? Try native Docker for a couple days and see for yourself :)

  • Second, the lock-in argument. "If you use Vagrant as an abstraction, you will not be locked into Docker!". From the point of view of Vagrant, which is designed to manage machines, this makes perfect sense: aren't containers just another kind of machine? Just like Amazon EC2 and VMware, we must be careful not to tie our provisioning tools to any particular vendor! This would create lock-in - better to abstract it all away with Vagrant. Except this misses the point of Docker entirely. Docker doesn't provision machines; it wraps your application in a lightweight portable runtime which can be dropped anywhere.

What runtime you choose for your application has nothing to do with how you provision your machines! For example it's pretty frequent to deploy applications to machines which are provisioned by someone else (for example an EC2 instance deployed by your system administrator, perhaps using Vagrant), or to bare metal machines which Vagrant can't provision at all. Conversely, you may use Vagrant to provision machines which have nothing to do with developing your application - for example a ready-to-use Windows IIS box or something. Or you may use Vagrant to provision machines for projects which don't use Docker - perhaps they use a combination of rubygems and rvm for dependency management and sandboxing for example.

In summary: Vagrant is for managing machines, and Docker is for building and running application environments.

Why do I get permission denied when I try use "make" to install something?

On many source packages (e.g. for most GNU software), the building system may know about the DESTDIR make variable, so you can often do:

 make install DESTDIR=/tmp/myinst/
 sudo cp -va /tmp/myinst/ /

The advantage of this approach is that make install don't need to run as root, so you cannot end up with files compiled as root (or root-owned files in your build tree).

How can I change the width and height of slides on Slick Carousel?

I know there is already an answer to this but I just found a better solution using the variableWidth parameter, just set it to true in the settings of each breakpoint, like this:

$('#featured-articles').slick({
  arrows: true,
  autoplay: true,
  autoplaySpeed: 3000,
  dots: true,
  draggable: false,
  fade: true,
  infinite: false,
  responsive: [
  {
    breakpoint: 620,
    settings: {
        arrows: true,
        variableWidth: true
    }
  },
  {
    breakpoint: 345,
    settings: {
        arrows: true,
        variableWidth: true
    }
  }
  ]
});

Case-insensitive search in Rails model

In postgres:

 user = User.find(:first, :conditions => ['username ~* ?', "regedarek"])

Jquery Ajax Loading image

Its a bit late but if you don't want to use a div specifically, I usually do it like this...

var ajax_image = "<img src='/images/Loading.gif' alt='Loading...' />";
$('#ReplaceDiv').html(ajax_image);

ReplaceDiv is the div that the Ajax inserts too. So when it arrives, the image is replaced.

Android: How do bluetooth UUIDs work?

To sum up: UUid is used to uniquely identify applications. Each application has a unique UUid

So, use the same UUid for each device

How to remove array element in mongodb?

If you use the Mongoose API and looking to pull a sub/child object: Read this document Don't forget to use save() when you're done editing otherwise the changes won't be saved to the database.

MySQL parameterized queries

You have a few options available. You'll want to get comfortable with python's string iterpolation. Which is a term you might have more success searching for in the future when you want to know stuff like this.

Better for queries:

some_dictionary_with_the_data = {
    'name': 'awesome song',
    'artist': 'some band',
    etc...
}
cursor.execute ("""
            INSERT INTO Songs (SongName, SongArtist, SongAlbum, SongGenre, SongLength, SongLocation)
            VALUES
                (%(name)s, %(artist)s, %(album)s, %(genre)s, %(length)s, %(location)s)

        """, some_dictionary_with_the_data)

Considering you probably have all of your data in an object or dictionary already, the second format will suit you better. Also it sucks to have to count "%s" appearances in a string when you have to come back and update this method in a year :)

What's the best three-way merge tool?

Source Gear Diff Merge:

Cross-platform, true three-way merges and it's completely free for commercial or personal usage.

enter image description here

How can a LEFT OUTER JOIN return more records than exist in the left table?

if multiple (x) rows in Dim_Member are associated with a single row in Susp_Visits, there will be x rows in the resul set.

Failed to load c++ bson extension

For my case, I npm install all modules on my local machine (Mac), and I did not include node_modules in .gitignore and uploaded to github. Then I cloned the project to my aws, as you know, it is running Linux, so I got the errors. What I did is just include node_modules in .gitignore, and use npm install in my aws instance, then it works.

Your project contains error(s), please fix it before running it

I come across this error often when I import a new project in my workspace.

Reason: Some necessary files (Like R.Java) is not generated in its respective packages.

Cure: Clean and build projects, All the files that needs to be auto generated will be there on place after building the project.

Best Luck.

How do I get the latest version of my code?

If the above commands didn't help you use this method:

  1. Go to the git archive where you have Fork
  2. Click Settings> Scroll down and click Delete this repository
  3. Confirm delete
  4. Fork again, and re-enter the git clone <url_git>
  5. You already have the latest version

How to install pywin32 module in windows 7

Quoting the README at https://github.com/mhammond/pywin32:

By far the easiest way to use pywin32 is to grab binaries from the most recent release

Just download the installer for your version of Python from https://github.com/mhammond/pywin32/releases and run it, and you're done.

How do I retrieve the number of columns in a Pandas data frame?

Alternative:

df.shape[1]

(df.shape[0] is the number of rows)

Box shadow in IE7 and IE8

in ie8 you can try

-ms-filter: "progid:DXImageTransform.Microsoft.Shadow(Strength=5, Direction=135, Color='#c0c0c0')";
 filter: progid:DXImageTransform.Microsoft.Shadow(Strength=5, Direction=135, Color='#c0c0c0');

caveat: in ie8 you loose smooth fonts for some reason, they will look ragged

ASP.NET MVC3 Razor - Html.ActionLink style

Reviving an old question because it seems to appear at the top of search results.

I wanted to retain transition effects while still being able to style the actionlink so I came up with this solution.

  1. I wrapped the action link with a div that would contain the parent style:
<div class="parent-style-one">
      @Html.ActionLink("Homepage", "Home", "Home")
</div>
  1. Next I create the CSS for the div, this will be the parent css and will be inherited by the child elements such as the action link.
  .parent-style-one {
     /* your styles here */
  }
  1. Because all an action link is, is an element when broken down as html so you just need to target that element in your css selection:
  .parent-style-one a {
     text-decoration: none;
  }
  1. For transition effects I did this:
  .parent-style-one a:hover {
        text-decoration: underline;
        -webkit-transition-duration: 1.1s; /* Safari */
        transition-duration: 1.1s;         
  }

This way I only target the child elements of the div in this case the action link and still be able to apply transition effects.

How to get a list of programs running with nohup

You cannot exactly get a list of commands started with nohup but you can see them along with your other processes by using the command ps x. Commands started with nohup will have a question mark in the TTY column.

Setting ANDROID_HOME enviromental variable on Mac OS X

A lot of correct answers here. However, one item is missing and I wasn't able to run the emulator from the command line without it.

export JAVA_HOME=$(/usr/libexec/java_home)
export PATH=$PATH:$JAVA_HOME/bin

export ANDROID_HOME=$HOME/Library/Android/sdk
export PATH=$PATH:$ANDROID_HOME/emulator       # can't run emulator without it
export PATH=$PATH:$ANDROID_HOME/tools
export PATH=$PATH:$ANDROID_HOME/platform-tools

So it's a compilation of the answers above plus a solution for this problem.

And if you use zsh (instead of bash) the file to edit is ~/.zshrc.

Git vs Team Foundation Server

People need to put down the gun, step away from the ledge, and think for a minute. It turns out there are objective, concrete, and undeniable advantages to DVCS that will make a HUGE difference in a team's productivity.

It all comes down to Branching and Merging.

Before DVCS, the guiding principle was "Pray to God that you don't have to get into branching and merging. And if you do, at least beg Him to let it be very, very simple."

Now, with DVCS, branching (and merging) is so much improved, the guiding principle is, "Do it at the drop of a hat. It will give you a ton of benefits and not cause you any problems."

And that is a HUGE productivity booster for any team.

The problem is, for people to understand what I just said and be convinced that it is true, they have to first invest in a little bit of a learning curve. They don't have to learn Git or any other DVCS itself ... they just need to learn how Git does branching and merging. Read and re-read some articles and blog posts, taking it slow, and working through it until you see it. That might take the better part of 2 or 3 full days.

But once you see that, you won't even consider choosing a non-DVCS. Because there really are clear, objective, concrete advantages to DVCS, and the biggest wins are in the area of branching and merging.

SQL Developer is returning only the date, not the time. How do I fix this?

Well I found this way :

Oracle SQL Developer (Left top icon) > Preferences > Database > NLS and set the Date Format as MM/DD/YYYY HH24:MI:SS

enter image description here

Linux command to list all available commands and aliases

There is the

type -a mycommand

command which lists all aliases and commands in $PATH where mycommand is used. Can be used to check if the command exists in several variants. Other than that... There's probably some script around that parses $PATH and all aliases, but don't know about any such script.

Escaping single quote in PHP when inserting into MySQL

You should just pass the variable (or data) inside "mysql_real_escape_string(trim($val))"

where $val is the data which is troubling you.

How do I get logs from all pods of a Kubernetes replication controller?

You can use labels

kubectl logs -l app=elasticsearch

How do I use typedef and typedef enum in C?

typedef enum state {DEAD,ALIVE} State;
|     | |                     | |   |^ terminating semicolon, required! 
|     | |   type specifier    | |   |
|     | |                     | ^^^^^  declarator (simple name)
|     | |                     |    
|     | ^^^^^^^^^^^^^^^^^^^^^^^  
|     |
^^^^^^^-- storage class specifier (in this case typedef)

The typedef keyword is a pseudo-storage-class specifier. Syntactically, it is used in the same place where a storage class specifier like extern or static is used. It doesn't have anything to do with storage. It means that the declaration doesn't introduce the existence of named objects, but rather, it introduces names which are type aliases.

After the above declaration, the State identifier becomes an alias for the type enum state {DEAD,ALIVE}. The declaration also provides that type itself. However that isn't typedef doing it. Any declaration in which enum state {DEAD,ALIVE} appears as a type specifier introduces that type into the scope:

enum state {DEAD, ALIVE} stateVariable;

If enum state has previously been introduced the typedef has to be written like this:

typedef enum state State;

otherwise the enum is being redefined, which is an error.

Like other declarations (except function parameter declarations), the typedef declaration can have multiple declarators, separated by a comma. Moreover, they can be derived declarators, not only simple names:

typedef unsigned long ulong, *ulongptr;
|     | |           | |  1 | |   2   |
|     | |           | |    | ^^^^^^^^^--- "pointer to" declarator
|     | |           | ^^^^^^------------- simple declarator
|     | ^^^^^^^^^^^^^-------------------- specifier-qualifier list
^^^^^^^---------------------------------- storage class specifier

This typedef introduces two type names ulong and ulongptr, based on the unsigned long type given in the specifier-qualifier list. ulong is just a straight alias for that type. ulongptr is declared as a pointer to unsigned long, thanks to the * syntax, which in this role is a kind of type construction operator which deliberately mimics the unary * for pointer dereferencing used in expressions. In other words ulongptr is an alias for the "pointer to unsigned long" type.

Alias means that ulongptr is not a distinct type from unsigned long *. This is valid code, requiring no diagnostic:

unsigned long *p = 0;
ulongptr q = p;

The variables q and p have exactly the same type.

The aliasing of typedef isn't textual. For instance if user_id_t is a typedef name for the type int, we may not simply do this:

unsigned user_id_t uid;  // error! programmer hoped for "unsigned int uid". 

This is an invalid type specifier list, combining unsigned with a typedef name. The above can be done using the C preprocessor:

#define user_id_t int
unsigned user_id_t uid;

whereby user_id_t is macro-expanded to the token int prior to syntax analysis and translation. While this may seem like an advantage, it is a false one; avoid this in new programs.

Among the disadvantages that it doesn't work well for derived types:

 #define silly_macro int *

 silly_macro not, what, you, think;

This declaration doesn't declare what, you and think as being of type "pointer to int" because the macro-expansion is:

 int * not, what, you, think;

The type specifier is int, and the declarators are *not, what, you and think. So not has the expected pointer type, but the remaining identifiers do not.

And that's probably 99% of everything about typedef and type aliasing in C.

What is a good practice to check if an environmental variable exists or not?

I'd recommend the following solution.

It prints the env vars you didn't include, which lets you add them all at once. If you go for the for loop, you're going to have to rerun the program to see each missing var.

from os import environ

REQUIRED_ENV_VARS = {"A", "B", "C", "D"}
diff = REQUIRED_ENV_VARS.difference(environ)
if len(diff) > 0:
    raise EnvironmentError(f'Failed because {diff} are not set')

How to deal with http status codes other than 200 in Angular 2

Include required imports and you can make ur decision in handleError method Error status will give the error code

import { HttpClient, HttpErrorResponse } from '@angular/common/http';
import {Observable, throwError} from "rxjs/index";
import { catchError, retry } from 'rxjs/operators';
import {ApiResponse} from "../model/api.response";
import { TaxType } from '../model/taxtype.model'; 

private handleError(error: HttpErrorResponse) {
if (error.error instanceof ErrorEvent) {
  // A client-side or network error occurred. Handle it accordingly.
  console.error('An error occurred:', error.error.message);
} else {
  // The backend returned an unsuccessful response code.
  // The response body may contain clues as to what went wrong,
  console.error(
    `Backend returned code ${error.status}, ` +
    `body was: ${error.error}`);
}
// return an observable with a user-facing error message
return throwError(
  'Something bad happened; please try again later.');
  };

  getTaxTypes() : Observable<ApiResponse> {
return this.http.get<ApiResponse>(this.baseUrl).pipe(
  catchError(this.handleError)
);
  }

bootstrap datepicker change date event doesnt fire up when manually editing dates or clearing date

I found a short solution for it. No extra code is needed just trigger the changeDate event. E.g. $('.datepicker').datepicker().trigger('changeDate');

How do I make an auto increment integer field in Django?

What I needed: A document number with a fixed number of integers that would also act like an AutoField.

My searches took me all over incl. this page.

Finally I did something like this:

I created a table with a DocuNumber field as an IntegerField with foll. attributes:

  • max_length=6
  • primary_key=True
  • unique=True
  • default=100000

The max_length value anything as required (and thus the corresponding default= value).

A warning is issued while creating the said model, which I could ignore.

Afterwards, created a document (dummy) whence as expected, the document had an integer field value of 100000.

Afterwards changed the model key field as:

  • Changed the field type as: AutoField
  • Got rid of the max_length And defaultattributes
  • Retained the primary_key = True attribute

The next (desired document) created had the value as 100001 with subsequent numbers getting incremented by 1.

So far so good.

How does System.out.print() work?

I think you are confused with the printf(String format, Object... args) method. The first argument is the format string, which is mandatory, rest you can pass an arbitrary number of Objects.

There is no such overload for both the print() and println() methods.

How to convert jsonString to JSONObject in Java

Codehaus Jackson - I have been this awesome API since 2012 for my RESTful webservice and JUnit tests. With their API, you can:

(1) Convert JSON String to Java bean

public static String beanToJSONString(Object myJavaBean) throws Exception {
    ObjectMapper jacksonObjMapper = new ObjectMapper();
    return jacksonObjMapper.writeValueAsString(myJavaBean);
}

(2) Convert JSON String to JSON object (JsonNode)

public static JsonNode stringToJSONObject(String jsonString) throws Exception {
    ObjectMapper jacksonObjMapper = new ObjectMapper();
    return jacksonObjMapper.readTree(jsonString);
}

//Example:
String jsonString = "{\"phonetype\":\"N95\",\"cat\":\"WP\"}";   
JsonNode jsonNode = stringToJSONObject(jsonString);
Assert.assertEquals("Phonetype value not legit!", "N95", jsonNode.get("phonetype").getTextValue());
Assert.assertEquals("Cat value is tragic!", "WP", jsonNode.get("cat").getTextValue());

(3) Convert Java bean to JSON String

    public static Object JSONStringToBean(Class myBeanClass, String JSONString) throws Exception {
    ObjectMapper jacksonObjMapper = new ObjectMapper();
    return jacksonObjMapper.readValue(JSONString, beanClass);
}

REFS:

  1. Codehaus Jackson

  2. JsonNode API - How to use, navigate, parse and evaluate values from a JsonNode object

  3. Tutorial - Simple tutorial how to use Jackson to convert JSON string to JsonNode

How to use Python requests to fake a browser visit a.k.a and generate User Agent?

The root of the answer is that the person asking the question needs to have a JavaScript interpreter to get what they are after. What I have found is I am able to get all of the information I wanted on a website in json before it was interpreted by JavaScript. This has saved me a ton of time in what would be parsing html hoping each webpage is in the same format.

So when you get a response from a website using requests really look at the html/text because you might find the javascripts JSON in the footer ready to be parsed.

How to set java.net.preferIPv4Stack=true at runtime?

well,

I used System.setProperty("java.net.preferIPv4Stack" , "true"); and it works from JAVA, but it doesn't work on JBOSS AS7.

Here is my work around solution,

Add the below line to the end of the file ${JBOSS_HOME}/bin/standalone.conf.bat (just after :JAVA_OPTS_SET )

set "JAVA_OPTS=%JAVA_OPTS% -Djava.net.preferIPv4Stack=true"

Note: restart JBoss server

How to implement and do OCR in a C# project?

If anyone is looking into this, I've been trying different options and the following approach yields very good results. The following are the steps to get a working example:

  1. Add .NET Wrapper for tesseract to your project. It can be added via NuGet package Install-Package Tesseract(https://github.com/charlesw/tesseract).
  2. Go to the Downloads section of the official Tesseract project (https://code.google.com/p/tesseract-ocr/ EDIT: It's now located here: https://github.com/tesseract-ocr/langdata).
  3. Download the preferred language data, example: tesseract-ocr-3.02.eng.tar.gz English language data for Tesseract 3.02.
  4. Create tessdata directory in your project and place the language data files in it.
  5. Go to Properties of the newly added files and set them to copy on build.
  6. Add a reference to System.Drawing.
  7. From .NET Wrapper repository, in the Samples directory copy the sample phototest.tif file into your project directory and set it to copy on build.
  8. Create the following two files in your project (just to get started):

Program.cs

using System;
using Tesseract;
using System.Diagnostics;

namespace ConsoleApplication
{
    class Program
    {
        public static void Main(string[] args)
        {
            var testImagePath = "./phototest.tif";
            if (args.Length > 0)
            {
                testImagePath = args[0];
            }

            try
            {
                var logger = new FormattedConsoleLogger();
                var resultPrinter = new ResultPrinter(logger);
                using (var engine = new TesseractEngine(@"./tessdata", "eng", EngineMode.Default))
                {
                    using (var img = Pix.LoadFromFile(testImagePath))
                    {
                        using (logger.Begin("Process image"))
                        {
                            var i = 1;
                            using (var page = engine.Process(img))
                            {
                                var text = page.GetText();
                                logger.Log("Text: {0}", text);
                                logger.Log("Mean confidence: {0}", page.GetMeanConfidence());

                                using (var iter = page.GetIterator())
                                {
                                    iter.Begin();
                                    do
                                    {
                                        if (i % 2 == 0)
                                        {
                                            using (logger.Begin("Line {0}", i))
                                            {
                                                do
                                                {
                                                    using (logger.Begin("Word Iteration"))
                                                    {
                                                        if (iter.IsAtBeginningOf(PageIteratorLevel.Block))
                                                        {
                                                            logger.Log("New block");
                                                        }
                                                        if (iter.IsAtBeginningOf(PageIteratorLevel.Para))
                                                        {
                                                            logger.Log("New paragraph");
                                                        }
                                                        if (iter.IsAtBeginningOf(PageIteratorLevel.TextLine))
                                                        {
                                                            logger.Log("New line");
                                                        }
                                                        logger.Log("word: " + iter.GetText(PageIteratorLevel.Word));
                                                    }
                                                } while (iter.Next(PageIteratorLevel.TextLine, PageIteratorLevel.Word));
                                            }
                                        }
                                        i++;
                                    } while (iter.Next(PageIteratorLevel.Para, PageIteratorLevel.TextLine));
                                }
                            }
                        }
                    }
                }
            }
            catch (Exception e)
            {
                Trace.TraceError(e.ToString());
                Console.WriteLine("Unexpected Error: " + e.Message);
                Console.WriteLine("Details: ");
                Console.WriteLine(e.ToString());
            }
            Console.Write("Press any key to continue . . . ");
            Console.ReadKey(true);
        }



        private class ResultPrinter
        {
            readonly FormattedConsoleLogger logger;

            public ResultPrinter(FormattedConsoleLogger logger)
            {
                this.logger = logger;
            }

            public void Print(ResultIterator iter)
            {
                logger.Log("Is beginning of block: {0}", iter.IsAtBeginningOf(PageIteratorLevel.Block));
                logger.Log("Is beginning of para: {0}", iter.IsAtBeginningOf(PageIteratorLevel.Para));
                logger.Log("Is beginning of text line: {0}", iter.IsAtBeginningOf(PageIteratorLevel.TextLine));
                logger.Log("Is beginning of word: {0}", iter.IsAtBeginningOf(PageIteratorLevel.Word));
                logger.Log("Is beginning of symbol: {0}", iter.IsAtBeginningOf(PageIteratorLevel.Symbol));

                logger.Log("Block text: \"{0}\"", iter.GetText(PageIteratorLevel.Block));
                logger.Log("Para text: \"{0}\"", iter.GetText(PageIteratorLevel.Para));
                logger.Log("TextLine text: \"{0}\"", iter.GetText(PageIteratorLevel.TextLine));
                logger.Log("Word text: \"{0}\"", iter.GetText(PageIteratorLevel.Word));
                logger.Log("Symbol text: \"{0}\"", iter.GetText(PageIteratorLevel.Symbol));
            }
        }
    }
}

FormattedConsoleLogger.cs

using System;
using System.Collections.Generic;
using System.Text;
using Tesseract;

namespace ConsoleApplication
{
    public class FormattedConsoleLogger
    {
        const string Tab = "    ";
        private class Scope : DisposableBase
        {
            private int indentLevel;
            private string indent;
            private FormattedConsoleLogger container;

            public Scope(FormattedConsoleLogger container, int indentLevel)
            {
                this.container = container;
                this.indentLevel = indentLevel;
                StringBuilder indent = new StringBuilder();
                for (int i = 0; i < indentLevel; i++)
                {
                    indent.Append(Tab);
                }
                this.indent = indent.ToString();
            }

            public void Log(string format, object[] args)
            {
                var message = String.Format(format, args);
                StringBuilder indentedMessage = new StringBuilder(message.Length + indent.Length * 10);
                int i = 0;
                bool isNewLine = true;
                while (i < message.Length)
                {
                    if (message.Length > i && message[i] == '\r' && message[i + 1] == '\n')
                    {
                        indentedMessage.AppendLine();
                        isNewLine = true;
                        i += 2;
                    }
                    else if (message[i] == '\r' || message[i] == '\n')
                    {
                        indentedMessage.AppendLine();
                        isNewLine = true;
                        i++;
                    }
                    else
                    {
                        if (isNewLine)
                        {
                            indentedMessage.Append(indent);
                            isNewLine = false;
                        }
                        indentedMessage.Append(message[i]);
                        i++;
                    }
                }

                Console.WriteLine(indentedMessage.ToString());

            }

            public Scope Begin()
            {
                return new Scope(container, indentLevel + 1);
            }

            protected override void Dispose(bool disposing)
            {
                if (disposing)
                {
                    var scope = container.scopes.Pop();
                    if (scope != this)
                    {
                        throw new InvalidOperationException("Format scope removed out of order.");
                    }
                }
            }
        }

        private Stack<Scope> scopes = new Stack<Scope>();

        public IDisposable Begin(string title = "", params object[] args)
        {
            Log(title, args);
            Scope scope;
            if (scopes.Count == 0)
            {
                scope = new Scope(this, 1);
            }
            else
            {
                scope = ActiveScope.Begin();
            }
            scopes.Push(scope);
            return scope;
        }

        public void Log(string format, params object[] args)
        {
            if (scopes.Count > 0)
            {
                ActiveScope.Log(format, args);
            }
            else
            {
                Console.WriteLine(String.Format(format, args));
            }
        }

        private Scope ActiveScope
        {
            get
            {
                var top = scopes.Peek();
                if (top == null) throw new InvalidOperationException("No current scope");
                return top;
            }
        }
    }
}

python convert list to dictionary

Not sure whether it would help you or not but it works to me:

l = ["a", "b", "c", "d", "e"]
outRes = dict((l[i], l[i+1]) if i+1 < len(l) else (l[i], '') for i in xrange(len(l)))

Abort trap 6 error in C

You are writing to memory you do not own:

int board[2][50]; //make an array with 3 columns  (wrong)
                  //(actually makes an array with only two 'columns')
...
for (i=0; i<num3+1; i++)
    board[2][i] = 'O';
          ^

Change this line:

int board[2][50]; //array with 2 columns (legal indices [0-1][0-49])
          ^

To:

int board[3][50]; //array with 3 columns (legal indices [0-2][0-49])
          ^

When creating an array, the value used to initialize: [3] indicates array size.
However, when accessing existing array elements, index values are zero based.

For an array created: int board[3][50];
Legal indices are board[0][0]...board[2][49]

EDIT To address bad output comment and initialization comment

add an additional "\n" for formatting output:

Change:

  ...
  for (k=0; k<50;k++) {
     printf("%d",board[j][k]);
  }
 }

       ...

To:

  ...
  for (k=0; k<50;k++) {
     printf("%d",board[j][k]);
  }
  printf("\n");//at the end of every row, print a new line
}
...  

Initialize board variable:

int board[3][50] = {0};//initialize all elements to zero

( array initialization discussion... )

npm WARN package.json: No repository field

It's just a check as of NPM v1.2.20, they report this as a warning.

However, don't worry, there are sooooooo many packages which still don't have the repository field in their package.json. The field is used for informational purposes.

In the case you're a package author, put the repository in your package.json, like this:

"repository": {
  "type": "git",
  "url": "git://github.com/username/repository.git"
}

Read more about the repository field, and see the logged bug for further details.


Additionally, as originally reported by @dan_nl, you can set private key in your package.json.
This will not only stop you from accidentally running npm publish in your app, but will also stop NPM from printing warnings regarding package.json problems.

{
  "name": "my-super-amazing-app",
  "version": "1.0.0",
  "private": true
}

lists and arrays in VBA

You will have to change some of your data types but the basics of what you just posted could be converted to something similar to this given the data types I used may not be accurate.

Dim DateToday As String: DateToday = Format(Date, "yyyy/MM/dd")
Dim Computers As New Collection
Dim disabledList As New Collection
Dim compArray(1 To 1) As String

'Assign data to first item in array
compArray(1) = "asdf"

'Format = Item, Key
Computers.Add "ErrorState", "Computer Name"

'Prints "ErrorState"
Debug.Print Computers("Computer Name")

Collections cannot be sorted so if you need to sort data you will probably want to use an array.

Here is a link to the outlook developer reference. http://msdn.microsoft.com/en-us/library/office/ff866465%28v=office.14%29.aspx

Another great site to help you get started is http://www.cpearson.com/Excel/Topic.aspx

Moving everything over to VBA from VB.Net is not going to be simple since not all the data types are the same and you do not have the .Net framework. If you get stuck just post the code you're stuck converting and you will surely get some help!

Edit:

Sub ArrayExample()
    Dim subject As String
    Dim TestArray() As String
    Dim counter As Long

    subject = "Example"
    counter = Len(subject)

    ReDim TestArray(1 To counter) As String

    For counter = 1 To Len(subject)
        TestArray(counter) = Right(Left(subject, counter), 1)
    Next
End Sub

Android Webview - Webpage should fit the device screen

These work for me and fit the WebView to screen width:

// get from xml, with all size set "fill_parent"  
webView = (WebView) findViewById(R.id.webview_in_layout);  
// fit the width of screen
webView.getSettings().setLayoutAlgorithm(LayoutAlgorithm.SINGLE_COLUMN); 
// remove a weird white line on the right size
webView.setScrollBarStyle(WebView.SCROLLBARS_OUTSIDE_OVERLAY);  

Thanks above advises and White line in eclipse Web view

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

As the error states - the database is not open - it was previously shut down, and someone left it in the middle of the startup process. They may either be intentional, or unintentional (i.e., it was supposed to be open, but failed to do so).

Assuming that's nothing wrong with the database itself, you could open it with a simple statement:(Since the question is asked specifically in the context of SQLPlus, kindly remember to put a statement terminator(Semicolon) at the end mandatorily, otherwise, it will result in an error.)

ALTER DATABASE OPEN;

Can jQuery get all CSS styles associated with an element?

Why not use .style of the DOM element? It's an object which contains members such as width and backgroundColor.

How to invoke a Linux shell command from Java

Building on @Tim's example to make a self-contained method:

import java.io.BufferedReader;
import java.io.File;
import java.io.InputStreamReader;
import java.util.ArrayList;

public class Shell {

    /** Returns null if it failed for some reason.
     */
    public static ArrayList<String> command(final String cmdline,
    final String directory) {
        try {
            Process process = 
                new ProcessBuilder(new String[] {"bash", "-c", cmdline})
                    .redirectErrorStream(true)
                    .directory(new File(directory))
                    .start();

            ArrayList<String> output = new ArrayList<String>();
            BufferedReader br = new BufferedReader(
                new InputStreamReader(process.getInputStream()));
            String line = null;
            while ( (line = br.readLine()) != null )
                output.add(line);

            //There should really be a timeout here.
            if (0 != process.waitFor())
                return null;

            return output;

        } catch (Exception e) {
            //Warning: doing this is no good in high quality applications.
            //Instead, present appropriate error messages to the user.
            //But it's perfectly fine for prototyping.

            return null;
        }
    }

    public static void main(String[] args) {
        test("which bash");

        test("find . -type f -printf '%T@\\\\t%p\\\\n' "
            + "| sort -n | cut -f 2- | "
            + "sed -e 's/ /\\\\\\\\ /g' | xargs ls -halt");

    }

    static void test(String cmdline) {
        ArrayList<String> output = command(cmdline, ".");
        if (null == output)
            System.out.println("\n\n\t\tCOMMAND FAILED: " + cmdline);
        else
            for (String line : output)
                System.out.println(line);

    }
}

(The test example is a command that lists all files in a directory and its subdirectories, recursively, in chronological order.)

By the way, if somebody can tell me why I need four and eight backslashes there, instead of two and four, I can learn something. There is one more level of unescaping happening than what I am counting.

Edit: Just tried this same code on Linux, and there it turns out that I need half as many backslashes in the test command! (That is: the expected number of two and four.) Now it's no longer just weird, it's a portability problem.

MongoDB query multiple collections at once

Perform multiple queries or use embedded documents or look at "database references".

How to remove last n characters from a string in Bash?

You can do like this:

#!/bin/bash

v="some string.rtf"

v2=${v::-4}

echo "$v --> $v2"

Accessing Redux state in an action creator?

When your scenario is simple you can use

import store from '../store';

export const SOME_ACTION = 'SOME_ACTION';
export function someAction() {
  return {
    type: SOME_ACTION,
    items: store.getState().otherReducer.items,
  }
}

But sometimes your action creator need to trigger multi actions

for example async request so you need REQUEST_LOAD REQUEST_LOAD_SUCCESS REQUEST_LOAD_FAIL actions

export const [REQUEST_LOAD, REQUEST_LOAD_SUCCESS, REQUEST_LOAD_FAIL] = [`REQUEST_LOAD`
    `REQUEST_LOAD_SUCCESS`
    `REQUEST_LOAD_FAIL`
]
export function someAction() {
    return (dispatch, getState) => {
        const {
            items
        } = getState().otherReducer;
        dispatch({
            type: REQUEST_LOAD,
            loading: true
        });
        $.ajax('url', {
            success: (data) => {
                dispatch({
                    type: REQUEST_LOAD_SUCCESS,
                    loading: false,
                    data: data
                });
            },
            error: (error) => {
                dispatch({
                    type: REQUEST_LOAD_FAIL,
                    loading: false,
                    error: error
                });
            }
        })
    }
}

Note: you need redux-thunk to return function in action creator

ZIP Code (US Postal Code) validation

Drupal 7 also has an easy solution here, this will allow you to validate against multiple countries.

https://drupal.org/project/postal_code_validation

You will need this module as well
https://drupal.org/project/postal_code

Test it in http://simplytest.me/

Guzzle 6: no more json() method for responses

I use $response->getBody()->getContents() to get JSON from response. Guzzle version 6.3.0.

Resize a picture to fit a JLabel

i have done the following and it worked perfectly

try {
        JFileChooser jfc = new JFileChooser();
        jfc.showOpenDialog(null);
        File f = jfc.getSelectedFile();
        Image bi = ImageIO.read(f);
        image1.setText("");
        image1.setIcon(new ImageIcon(bi.getScaledInstance(int width, int width, int width)));

    } catch (Exception e) {
    } 

ngModel cannot be used to register form controls with a parent formGroup directive

If you want to use [formGroup] with formControlName, you must replace name attribute with formControlNameformControlName.

Example:

This does not work because it uses the [formGroup] and name attribute.

<div [formGroup]="myGroup">
   <input name="firstName" [(ngModel)]="firstName">
</div>

You should replace the name attribute by formControlName and it will work fine like this following:

<div [formGroup]="myGroup">
   <input formControlName="firstName" [(ngModel)]="firstName">
</div>

Check if a string contains a substring in SQL Server 2005, using a stored procedure

CHARINDEX() searches for a substring within a larger string, and returns the position of the match, or 0 if no match is found

if CHARINDEX('ME',@mainString) > 0
begin
    --do something
end

Edit or from daniels answer, if you're wanting to find a word (and not subcomponents of words), your CHARINDEX call would look like:

CHARINDEX(' ME ',' ' + REPLACE(REPLACE(@mainString,',',' '),'.',' ') + ' ')

(Add more recursive REPLACE() calls for any other punctuation that may occur)

How to find index of all occurrences of element in array?

Another alternative solution is to use Array.prototype.reduce():

["Nano","Volvo","BMW","Nano","VW","Nano"].reduce(function(a, e, i) {
    if (e === 'Nano')
        a.push(i);
    return a;
}, []);   // [0, 3, 5]

N.B.: Check the browser compatibility for reduce method and use polyfill if required.

'Source code does not match the bytecode' when debugging on a device

You can created AVD, select API Level equal your tagetApi andr compileApi, it works for me.

Restoring database from .mdf and .ldf files of SQL Server 2008

First google search yielded me this answer. So I thought of updating this with newer version of attach, detach.

Create database dbname 
On 
(   
Filename= 'path where you copied files',   
Filename ='path where you copied log'
)
For attach; 

Further,if your database is cleanly shutdown(there are no active transactions while database was shutdown) and you dont have log file,you can use below method,SQL server will create a new transaction log file..

Create database dbname 
    On 
    (   
    Filename= 'path where you copied files'   
    )
    For attach; 

if you don't specify transaction log file,SQL will try to look in the default path and will try to use it irrespective of whether database was cleanly shutdown or not..

Here is what MSDN has to say about this..

If a read-write database has a single log file and you do not specify a new location for the log file, the attach operation looks in the old location for the file. If it is found, the old log file is used, regardless of whether the database was shut down cleanly. However, if the old log file is not found and if the database was shut down cleanly and has no active log chain, the attach operation attempts to build a new log file for the database.

There are some restrictions with this approach and some side affects too..

1.attach-and-detach operations both disable cross-database ownership chaining for the database
2.Database trustworthy is set to off
3.Detaching a read-only database loses information about the differential bases of differential backups.

Most importantly..you can't attach a database with recent versions to an earlier version

References:
https://msdn.microsoft.com/en-in/library/ms190794.aspx

Volley JsonObjectRequest Post request not working

When you working with JsonObject request you need to pass the parameters right after you pass the link in the initialization , take a look on this code :

        HashMap<String, String> params = new HashMap<>();
        params.put("user", "something" );
        params.put("some_params", "something" );

    JsonObjectRequest request = new JsonObjectRequest(Request.Method.POST, "request_URL", new JSONObject(params), new Response.Listener<JSONObject>() {
        @Override
        public void onResponse(JSONObject response) {

           // Some code 

        }
    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
            //handle errors
        }
    });


}

Can't find System.Windows.Media namespace?

The System.Windows.Media.Imaging namespace is part of PresentationCore.dll (if you are using Visual Studio 2008 then the WPF application template will automatically add this reference). Note that this namespace is not a direct wrapping of the WIC library, although a large proportion of the more common uses are still available and it is relatively obvious how these map to the WIC versions. For more information on the classes in this namespace check out

http://msdn2.microsoft.com/en-us/library/system.windows.media.imaging.aspx

Install Visual Studio 2013 on Windows 7

your log files shows it is stopping on error "0x8004C000"

From MS Website (http://social.technet.microsoft.com/wiki/contents/articles/15716.visual-studio-2012-and-the-error-code-2147205120.aspx):

Setup Status
Block

Restart not required
0x80044000 [-2147205120]

Restart required
0x8004C000 [-2147172352]

Description
If the only block to be reported is “Reboot Pending,” the returned value is the Incomplete-Reboot Required value (0x80048bc7).

Twitter bootstrap modal-backdrop doesn't disappear

the initial value of your data-backdrop attribute can be

"static","true", "false" .

static and true add the modal shadow, while false disable the shadow, so you just need to change this value with the first click to false . like this:

_x000D_
_x000D_
$(document).on('ready',function(){_x000D_
 _x000D_
 var count=0;_x000D_
 _x000D_
$('#id-which-triggers-modal').on('click',function(){_x000D_
  _x000D_
  if(count>0){_x000D_
  _x000D_
   $(this).attr('data-backdrop','false')_x000D_
  }_x000D_
  count++;_x000D_
});_x000D_
_x000D_
_x000D_
});
_x000D_
_x000D_
_x000D_

What's the meaning of "=>" (an arrow formed from equals & greater than) in JavaScript?

Adding simple CRUD example with Arrowfunction

 //Arrow Function
 var customers   = [
   {
     name: 'Dave',
     contact:'9192631770'
   },
   {
     name: 'Sarah',
     contact:'9192631770'
   },
   {
     name: 'Akhil',
     contact:'9928462656' 
   }],

// No Param READ
 getFirstCustomer = () => { 
   console.log(this);
   return customers[0];
 };
  console.log("First Customer "+JSON.stringify(getFirstCustomer())); // 'Dave' 

   //1 Param SEARCH
  getNthCustomer = index=>{
    if( index>customers.length)
    {
     return  "No such thing";
   }
   else{
       return customers[index];
     } 
  };
  console.log("Nth Customer is " +JSON.stringify(getNthCustomer(1))); 

   //2params ADD
  addCustomer = (name, contact)=> customers.push({
     'name': name,
     'contact':contact
    });
  addCustomer('Hitesh','8888813275');
  console.log("Added Customer "+JSON.stringify(customers)); 

  //2 param UPDATE
  updateCustomerName = (index, newName)=>{customers[index].name= newName};
  updateCustomerName(customers.length-1,"HiteshSahu");
  console.log("Updated Customer "+JSON.stringify(customers));

  //1 param DELETE
  removeCustomer = (customerToRemove) => customers.pop(customerToRemove);
  removeCustomer(getFirstCustomer());
  console.log("Removed Customer "+JSON.stringify(customers)); 

span with onclick event inside a tag

use onmouseup

try something like this

        <html>
        <head>
        <script type="text/javascript">
        function hide(){
        document.getElementById('span_hide').style.display="none";
        }
        </script>
        </head>

        <body>
        <a href="page" style="text-decoration:none;display:block;">
        <span   onmouseup="hide()" id="span_hide">Hide me</span>
        </a>
        </body>
        </html>

EDIT:

          <html>
        <head>
        <script type="text/javascript">
        $(document).ready(function(){
         $("a").click(function () { 
         $(this).fadeTo("fast", .5).removeAttr("href"); 
        });
        });
        function hide(){
        document.getElementById('span_hide').style.display="none";
        }
        </script>
        </head>

        <body>
        <a href="page.html" style="text-decoration:none;display:block;" onclick="return false" >
        <span   onmouseup="hide()" id="span_hide">Hide me</span>
        </a>
        </body>
        </html>

SyntaxError: cannot assign to operator

Instead of ((t[1])/length) * t[1] += string, you should use string += ((t[1])/length) * t[1]. (The other syntax issue - int is not iterable - will be your exercise to figure out.)

Select default option value from typescript angular 6

HTML

<select class='form-control'>
    <option *ngFor="let option of options"
    [selected]="option === nrSelect"
    [value]="option">
        {{ option }}
    </option>
</select>

Typescript

nrSelect = 47;
options = [41, 42, 47, 48];

How to specify different Debug/Release output directories in QMake .pro file

Old question, but still worth an up-to-date answer. Today it's common to do what Qt Creator does when shadow builds are used (they are enabled by default when opening a new project).

For each different build target and type, the right qmake is run with right arguments in a different build directory. Then that is just built with simple make.

So, imaginary directory structure might look like this.

/
|_/build-mylib-qt5-mingw32-debug
|_/build-mylib-qt5-mingw32-release
|_/build-mylib-qt4-msvc2010-debug
|_/build-mylib-qt4-msvc2010-release
|_/build-mylib-qt5-arm-debug
|_/build-mylib-qt5-arm-release
|_/mylib
  |_/include
  |_/src
  |_/resources

And the improtant thing is, a qmake is run in the build directory:

cd build-mylib-XXXX
/path/to/right/qmake ../mylib/mylib.pro CONFIG+=buildtype ...

Then it generates makefiles in build directory, and then make will generate files under it too. There is no risk of different versions getting mixed up, as long as qmake is never run in the source directory (if it is, better clean it up well!).

And when done like this, the .pro file from currently accepted answer is even simpler:

HEADERS += src/dialogs.h
SOURCES += src/main.cpp \
           src/dialogs.cpp

How can I remove a button or make it invisible in Android?

View controls (TextView, EditText, Button, Image, etc) all have a visibility property. This can be set to one of three values:

Visible - Displayed

android:visibility="visible"

Invisible - Hidden but space reserved

android:visibility="invisible"

Gone - Hidden completely

android:visibility="gone"

To set the visibility in code use the public constant available in the static View class:

Button button1 = (TextView)findViewById(R.id.button1);
button1.setVisibility(View.VISIBILE);

ASP.NET Identity DbContext confusion

There is a lot of confusion about IdentityDbContext, a quick search in Stackoverflow and you'll find these questions:
" Why is Asp.Net Identity IdentityDbContext a Black-Box?
How can I change the table names when using Visual Studio 2013 AspNet Identity?
Merge MyDbContext with IdentityDbContext"

To answer to all of these questions we need to understand that IdentityDbContext is just a class inherited from DbContext.
Let's take a look at IdentityDbContext source:

/// <summary>
/// Base class for the Entity Framework database context used for identity.
/// </summary>
/// <typeparam name="TUser">The type of user objects.</typeparam>
/// <typeparam name="TRole">The type of role objects.</typeparam>
/// <typeparam name="TKey">The type of the primary key for users and roles.</typeparam>
/// <typeparam name="TUserClaim">The type of the user claim object.</typeparam>
/// <typeparam name="TUserRole">The type of the user role object.</typeparam>
/// <typeparam name="TUserLogin">The type of the user login object.</typeparam>
/// <typeparam name="TRoleClaim">The type of the role claim object.</typeparam>
/// <typeparam name="TUserToken">The type of the user token object.</typeparam>
public abstract class IdentityDbContext<TUser, TRole, TKey, TUserClaim, TUserRole, TUserLogin, TRoleClaim, TUserToken> : DbContext
    where TUser : IdentityUser<TKey, TUserClaim, TUserRole, TUserLogin>
    where TRole : IdentityRole<TKey, TUserRole, TRoleClaim>
    where TKey : IEquatable<TKey>
    where TUserClaim : IdentityUserClaim<TKey>
    where TUserRole : IdentityUserRole<TKey>
    where TUserLogin : IdentityUserLogin<TKey>
    where TRoleClaim : IdentityRoleClaim<TKey>
    where TUserToken : IdentityUserToken<TKey>
{
    /// <summary>
    /// Initializes a new instance of <see cref="IdentityDbContext"/>.
    /// </summary>
    /// <param name="options">The options to be used by a <see cref="DbContext"/>.</param>
    public IdentityDbContext(DbContextOptions options) : base(options)
    { }

    /// <summary>
    /// Initializes a new instance of the <see cref="IdentityDbContext" /> class.
    /// </summary>
    protected IdentityDbContext()
    { }

    /// <summary>
    /// Gets or sets the <see cref="DbSet{TEntity}"/> of Users.
    /// </summary>
    public DbSet<TUser> Users { get; set; }

    /// <summary>
    /// Gets or sets the <see cref="DbSet{TEntity}"/> of User claims.
    /// </summary>
    public DbSet<TUserClaim> UserClaims { get; set; }

    /// <summary>
    /// Gets or sets the <see cref="DbSet{TEntity}"/> of User logins.
    /// </summary>
    public DbSet<TUserLogin> UserLogins { get; set; }

    /// <summary>
    /// Gets or sets the <see cref="DbSet{TEntity}"/> of User roles.
    /// </summary>
    public DbSet<TUserRole> UserRoles { get; set; }

    /// <summary>
    /// Gets or sets the <see cref="DbSet{TEntity}"/> of User tokens.
    /// </summary>
    public DbSet<TUserToken> UserTokens { get; set; }

    /// <summary>
    /// Gets or sets the <see cref="DbSet{TEntity}"/> of roles.
    /// </summary>
    public DbSet<TRole> Roles { get; set; }

    /// <summary>
    /// Gets or sets the <see cref="DbSet{TEntity}"/> of role claims.
    /// </summary>
    public DbSet<TRoleClaim> RoleClaims { get; set; }

    /// <summary>
    /// Configures the schema needed for the identity framework.
    /// </summary>
    /// <param name="builder">
    /// The builder being used to construct the model for this context.
    /// </param>
    protected override void OnModelCreating(ModelBuilder builder)
    {
        builder.Entity<TUser>(b =>
        {
            b.HasKey(u => u.Id);
            b.HasIndex(u => u.NormalizedUserName).HasName("UserNameIndex").IsUnique();
            b.HasIndex(u => u.NormalizedEmail).HasName("EmailIndex");
            b.ToTable("AspNetUsers");
            b.Property(u => u.ConcurrencyStamp).IsConcurrencyToken();

            b.Property(u => u.UserName).HasMaxLength(256);
            b.Property(u => u.NormalizedUserName).HasMaxLength(256);
            b.Property(u => u.Email).HasMaxLength(256);
            b.Property(u => u.NormalizedEmail).HasMaxLength(256);
            b.HasMany(u => u.Claims).WithOne().HasForeignKey(uc => uc.UserId).IsRequired();
            b.HasMany(u => u.Logins).WithOne().HasForeignKey(ul => ul.UserId).IsRequired();
            b.HasMany(u => u.Roles).WithOne().HasForeignKey(ur => ur.UserId).IsRequired();
        });

        builder.Entity<TRole>(b =>
        {
            b.HasKey(r => r.Id);
            b.HasIndex(r => r.NormalizedName).HasName("RoleNameIndex");
            b.ToTable("AspNetRoles");
            b.Property(r => r.ConcurrencyStamp).IsConcurrencyToken();

            b.Property(u => u.Name).HasMaxLength(256);
            b.Property(u => u.NormalizedName).HasMaxLength(256);

            b.HasMany(r => r.Users).WithOne().HasForeignKey(ur => ur.RoleId).IsRequired();
            b.HasMany(r => r.Claims).WithOne().HasForeignKey(rc => rc.RoleId).IsRequired();
        });

        builder.Entity<TUserClaim>(b => 
        {
            b.HasKey(uc => uc.Id);
            b.ToTable("AspNetUserClaims");
        });

        builder.Entity<TRoleClaim>(b => 
        {
            b.HasKey(rc => rc.Id);
            b.ToTable("AspNetRoleClaims");
        });

        builder.Entity<TUserRole>(b => 
        {
            b.HasKey(r => new { r.UserId, r.RoleId });
            b.ToTable("AspNetUserRoles");
        });

        builder.Entity<TUserLogin>(b =>
        {
            b.HasKey(l => new { l.LoginProvider, l.ProviderKey });
            b.ToTable("AspNetUserLogins");
        });

        builder.Entity<TUserToken>(b => 
        {
            b.HasKey(l => new { l.UserId, l.LoginProvider, l.Name });
            b.ToTable("AspNetUserTokens");
        });
    }
}


Based on the source code if we want to merge IdentityDbContext with our DbContext we have two options:

First Option:
Create a DbContext which inherits from IdentityDbContext and have access to the classes.

   public class ApplicationDbContext 
    : IdentityDbContext
{
    public ApplicationDbContext()
        : base("DefaultConnection")
    {
    }

    static ApplicationDbContext()
    {
        Database.SetInitializer<ApplicationDbContext>(new ApplicationDbInitializer());
    }

    public static ApplicationDbContext Create()
    {
        return new ApplicationDbContext();
    }

    // Add additional items here as needed
}


Extra Notes:

1) We can also change asp.net Identity default table names with the following solution:

    public class ApplicationDbContext : IdentityDbContext
    {    
        public ApplicationDbContext(): base("DefaultConnection")
        {
        }

        protected override void OnModelCreating(System.Data.Entity.DbModelBuilder modelBuilder)
        {
            base.OnModelCreating(modelBuilder);
            modelBuilder.Entity<IdentityUser>().ToTable("user");
            modelBuilder.Entity<ApplicationUser>().ToTable("user");

            modelBuilder.Entity<IdentityRole>().ToTable("role");
            modelBuilder.Entity<IdentityUserRole>().ToTable("userrole");
            modelBuilder.Entity<IdentityUserClaim>().ToTable("userclaim");
            modelBuilder.Entity<IdentityUserLogin>().ToTable("userlogin");
        }
    }

2) Furthermore we can extend each class and add any property to classes like 'IdentityUser', 'IdentityRole', ...

    public class ApplicationRole : IdentityRole<string, ApplicationUserRole>
{
    public ApplicationRole() 
    {
        this.Id = Guid.NewGuid().ToString();
    }

    public ApplicationRole(string name)
        : this()
    {
        this.Name = name;
    }

    // Add any custom Role properties/code here
}


// Must be expressed in terms of our custom types:
public class ApplicationDbContext 
    : IdentityDbContext<ApplicationUser, ApplicationRole, 
    string, ApplicationUserLogin, ApplicationUserRole, ApplicationUserClaim>
{
    public ApplicationDbContext()
        : base("DefaultConnection")
    {
    }

    static ApplicationDbContext()
    {
        Database.SetInitializer<ApplicationDbContext>(new ApplicationDbInitializer());
    }

    public static ApplicationDbContext Create()
    {
        return new ApplicationDbContext();
    }

    // Add additional items here as needed
}

To save time we can use AspNet Identity 2.0 Extensible Project Template to extend all the classes.

Second Option:(Not recommended)
We actually don't have to inherit from IdentityDbContext if we write all the code ourselves.
So basically we can just inherit from DbContext and implement our customized version of "OnModelCreating(ModelBuilder builder)" from the IdentityDbContext source code

Disable a textbox using CSS

You can't disable anything with CSS, that's a functional-issue. CSS is meant for design-issues. You could give the impression of a textbox being disabled, by setting washed-out colors on it.

To actually disable the element, you should use the disabled boolean attribute:

<input type="text" name="lname" disabled />

Demo: http://jsfiddle.net/p6rja/

Or, if you like, you can set this via JavaScript:

document.forms['formName']['inputName'].disabled = true;????

Demo: http://jsfiddle.net/655Su/

Keep in mind that disabled inputs won't pass their values through when you post data back to the server. If you want to hold the data, but disallow to directly edit it, you may be interested in setting it to readonly instead.

// Similar to <input value="Read-only" readonly>
document.forms['formName']['inputName'].readOnly = true;

Demo: http://jsfiddle.net/655Su/1/

This doesn't change the UI of the element, so you would need to do that yourself:

input[readonly] { 
    background: #CCC; 
    color: #333; 
    border: 1px solid #666 
}

You could also target any disabled element:

input[disabled] { /* styles */ }

The character encoding of the plain text document was not declared - mootool script

If you are using ASP.NET Core MVC project. This error message can be shown then you have the correct cshtml file in your Views folder but the action is missing in your controller.

Adding the missing action to the controller will fix it.

Catch error if iframe src fails to load . Error :-"Refused to display 'http://www.google.co.in/' in a frame.."

I faced similar problem. I solved it without using onload handler.I was working on AngularJs project so i used $interval and $ timeout. U can also use setTimeout and setInterval.Here's the code:

 var stopPolling;
 var doIframePolling;
 $scope.showIframe = true;
 doIframePolling = $interval(function () {
    if(document.getElementById('UrlIframe') && document.getElementById('UrlIframe').contentDocument.head && document.getElementById('UrlIframe').contentDocument.head.innerHTML != ''){
        $interval.cancel(doIframePolling);
        doIframePolling = undefined;
        $timeout.cancel(stopPolling);
        stopPolling = undefined;
        $scope.showIframe = true;
    }
},400);

stopPolling = $timeout(function () {
        $interval.cancel(doIframePolling);
        doIframePolling = undefined;
        $timeout.cancel(stopPolling);
        stopPolling = undefined;
        $scope.showIframe = false;     
},5000);

 $scope.$on("$destroy",function() {
        $timeout.cancel(stopPolling);
        $interval.cancel(doIframePolling);
 });

Every 0.4 Seconds keep checking the head of iFrame Document. I somthing is present.Loading was not stopped by CORS as CORS error shows blank page. If nothing is present after 5 seconds there was some error (Cors policy) etc.. Show suitable message.Thanks. I hope it solves your problem.

How to add calendar events in Android?

you have to add flag:

intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

or you will cause error with:

startActivity() from outside of an Activity context requires the FLAG_ACTIVITY_NEW_TASK

Check if an apt-get package is installed and then install it if it's not on Linux

This one-liner returns 1 (installed) or 0 (not installed) for the 'nano' package..

$(dpkg-query -W -f='${Status}' nano 2>/dev/null | grep -c "ok installed")

even if the package does not exist / is not available.

The example below installs the 'nano' package if it is not installed..

if [ $(dpkg-query -W -f='${Status}' nano 2>/dev/null | grep -c "ok installed") -eq 0 ];
then
  apt-get install nano;
fi

How do you find the current user in a Windows environment?

Username:

echo %USERNAME%

Domainname:

echo %USERDOMAIN%

You can get a complete list of environment variables by running the command set from the command prompt.

How do I perform query filtering in django templates

You can't do this, which is by design. The Django framework authors intended a strict separation of presentation code from data logic. Filtering models is data logic, and outputting HTML is presentation logic.

So you have several options. The easiest is to do the filtering, then pass the result to render_to_response. Or you could write a method in your model so that you can say {% for object in data.filtered_set %}. Finally, you could write your own template tag, although in this specific case I would advise against that.

angularjs: allows only numbers to be typed into a text box

This is the method that works for me. It's based in samnau anwser but allows to submit the form with ENTER, increase and decrease the number with UP and DOWN arrows, edition with DEL,BACKSPACE,LEFT and RIGHT, and navigate trough fields with TAB. Note that it works for positive integers such as an amount.

HTML:

<input ng-keypress="onlyNumbers($event)" min="0" type="number" step="1" ng-pattern="/^[0-9]{1,8}$/" ng-model="... >

ANGULARJS:

$scope.onlyNumbers = function(event){   
    var keys={
        'up': 38,'right':39,'down':40,'left':37,
        'escape':27,'backspace':8,'tab':9,'enter':13,'del':46,
        '0':48,'1':49,'2':50,'3':51,'4':52,'5':53,'6':54,'7':55,'8':56,'9':57
    };
    for(var index in keys) {
        if (!keys.hasOwnProperty(index)) continue;
        if (event.charCode==keys[index]||event.keyCode==keys[index]) {
            return; //default event
        }
    }   
    event.preventDefault();
};

OpenCV get pixel channel value from Mat image

The below code works for me, for both accessing and changing a pixel value.

For accessing pixel's channel value :

for (int i = 0; i < image.cols; i++) {
    for (int j = 0; j < image.rows; j++) {
        Vec3b intensity = image.at<Vec3b>(j, i);
        for(int k = 0; k < image.channels(); k++) {
            uchar col = intensity.val[k]; 
        }   
    }
}

For changing a pixel value of a channel :

uchar pixValue;
for (int i = 0; i < image.cols; i++) {
    for (int j = 0; j < image.rows; j++) {
        Vec3b &intensity = image.at<Vec3b>(j, i);
        for(int k = 0; k < image.channels(); k++) {
            // calculate pixValue
            intensity.val[k] = pixValue;
        }
     }
}

`

Source : Accessing pixel value

Remove credentials from Git

If your credentials are stored in the credential helper (generally the case), the portable way to remove a password persisted for a specific host is to call git credential reject:

  • in one line:

    $ echo "url=https://appharbor.com" | git credential reject
    
  • or interactively:

    $ git credential reject
    protocol=https
    host=gitlab.com
    [email protected]
    ?
    
    • ? is the Enter symbol, just hit Enter key twice at the end of input, don't copy/paste it
    • The username doesn't seem recognized by wincred, so avoid to filter by username on Windows

After that, to enter your new password, type git fetch.

https://git-scm.com/docs/git-credential

FlutterError: Unable to load asset

  1. you should start image path with assets word:

image: AssetImage('assets/images/pizza0.png')

  1. you must add each sub folder in a new line in pubspec.yaml

How to check if a Java 8 Stream is empty?

The other answers and comments are correct in that to examine the contents of a stream, one must add a terminal operation, thereby "consuming" the stream. However, one can do this and turn the result back into a stream, without buffering up the entire contents of the stream. Here are a couple examples:

static <T> Stream<T> throwIfEmpty(Stream<T> stream) {
    Iterator<T> iterator = stream.iterator();
    if (iterator.hasNext()) {
        return StreamSupport.stream(Spliterators.spliteratorUnknownSize(iterator, 0), false);
    } else {
        throw new NoSuchElementException("empty stream");
    }
}

static <T> Stream<T> defaultIfEmpty(Stream<T> stream, Supplier<T> supplier) {
    Iterator<T> iterator = stream.iterator();
    if (iterator.hasNext()) {
        return StreamSupport.stream(Spliterators.spliteratorUnknownSize(iterator, 0), false);
    } else {
        return Stream.of(supplier.get());
    }
}

Basically turn the stream into an Iterator in order to call hasNext() on it, and if true, turn the Iterator back into a Stream. This is inefficient in that all subsequent operations on the stream will go through the Iterator's hasNext() and next() methods, which also implies that the stream is effectively processed sequentially (even if it's later turned parallel). However, this does allow you to test the stream without buffering up all of its elements.

There is probably a way to do this using a Spliterator instead of an Iterator. This potentially allows the returned stream to have the same characteristics as the input stream, including running in parallel.

Emulate/Simulate iOS in Linux

  1. Run Ripple emulator(retired as of 2015-12-06) on Chrome
  2. Run iPadian on WineHQ
  3. Run QMole on Linux or Android
  4. Run XCode on PureDarwin

Row names & column names in R

As Oscar Wilde said

Consistency is the last refuge of the unimaginative.

R is more of an evolved rather than designed language, so these things happen. names() and colnames() work on a data.frame but names() does not work on a matrix:

R> DF <- data.frame(foo=1:3, bar=LETTERS[1:3])
R> names(DF)
[1] "foo" "bar"
R> colnames(DF)
[1] "foo" "bar"
R> M <- matrix(1:9, ncol=3, dimnames=list(1:3, c("alpha","beta","gamma")))
R> names(M)
NULL
R> colnames(M)
[1] "alpha" "beta"  "gamma"
R> 

Determine distance from the top of a div to top of window with javascript

I used this function to detect if the element is visible in view port

Code:

const vh = Math.max(document.documentElement.clientHeight || 0, window.innerHeight || 0);
$(window).scroll(function(){
var scrollTop     = $(window).scrollTop(),
elementOffset = $('.for-scroll').offset().top,
distance      = (elementOffset - scrollTop);
if(distance < vh){
    console.log('in view');
}
else{
    console.log('not in view');
}
});

MacOS Xcode CoreSimulator folder very big. Is it ok to delete content?

That directory is part of your user data and you can delete any user data without affecting Xcode seriously. You can delete the whole CoreSimulator/ directory. Xcode will recreate fresh instances there for you when you do your next simulator run. If you can afford losing any previous simulator data of your apps this is the easy way to get space.

Update: A related useful app is "DevCleaner for Xcode" https://apps.apple.com/app/devcleaner-for-xcode/id1388020431

How to solve the system.data.sqlclient.sqlexception (0x80131904) error

The datasource is by default .\SQLEXPRESS (its the instance where databases are placed by default) or if u changed the name of the instance during installation of sql server so i advise you to do this :

connectionString="Data Source=.\\yourInstance(defaulT Data source is SQLEXPRESS);
       Initial Catalog=databaseName;
       User ID=theuser if u use it;
       Password=thepassword if u use it;
       integrated security=true(if u don t use user and pass; else change it false)"

Without to knowing your instance, I could help with this one. Hope it helped

Trying to get property of non-object - Laravel 5

I got it working by using Jimmy Zoto's answer and adding a second parameter to my belongsTo. Here it is:

First, as suggested by Jimmy Zoto, my code in blade from

$article->poster->name 

to

$article->poster['name']

Next is to add a second parameter in my belongsTo, from

return $this->belongsTo('App\User');

to

return $this->belongsTo('App\User', 'user_id');

in which user_id is my foreign key in the news table.

Using grep to search for hex strings in a file

This seems to work for me:

LANG=C grep --only-matching --byte-offset --binary --text --perl-regexp "<\x-hex pattern>" <file>

short form:

LANG=C grep -obUaP "<\x-hex pattern>" <file>

Example:

LANG=C grep -obUaP "\x01\x02" /bin/grep

Output (cygwin binary):

153: <\x01\x02>
33210: <\x01\x02>
53453: <\x01\x02>

So you can grep this again to extract offsets. But don't forget to use binary mode again.

Note: LANG=C is needed to avoid utf8 encoding issues.

What is a vertical tab?

The ASCII vertical tab (\x0B)is still used in some databases and file formats as a new line WITHIN a field. For example:

Rails: How to list database tables/objects using the Rails console?

I hope my late answer can be of some help.
This will go to rails database console.

rails db

pretty print your query output

.headers on
.mode columns
(turn headers on and show database data in column mode )

Show the tables

.table

'.help' to see help.
Or use SQL statements like 'Select * from cars'

What is the difference between i++ & ++i in a for loop?

The difference is that the post-increment operator i++ returns i as it was before incrementing, and the pre-increment operator ++i returns i as it is after incrementing. If you're asking about a typical for loop:

for (i = 0; i < 10; i++)

or

for (i = 0; i < 10; ++i)

They're exactly the same, since you're not using i++ or ++i as a part of a larger expression.

Seedable JavaScript random number generator

If you want to be able to specify the seed, you just need to replace the calls to getSeconds() and getMinutes(). You could pass in an int and use half of it mod 60 for the seconds value and the other half modulo 60 to give you the other part.

That being said, this method looks like garbage. Doing proper random number generation is very hard. The obvious problem with this is that the random number seed is based on seconds and minutes. To guess the seed and recreate your stream of random numbers only requires trying 3600 different second and minute combinations. It also means that there are only 3600 different possible seeds. This is correctable, but I'd be suspicious of this RNG from the start.

If you want to use a better RNG, try the Mersenne Twister. It is a well tested and fairly robust RNG with a huge orbit and excellent performance.

EDIT: I really should be correct and refer to this as a Pseudo Random Number Generator or PRNG.

"Anyone who uses arithmetic methods to produce random numbers is in a state of sin."
                                                                                                                                                          --- John von Neumann

Dynamically display a CSV file as an HTML table on a web page

XmlGrid.net has tool to convert csv to html table. Here is the link: http://xmlgrid.net/csvToHtml.html

I used your sample data, and got the following html table:

<table>
<!--Created with XmlGrid Free Online XML Editor (http://xmlgrid.net)-->
<tr>
  <td>Name</td>
  <td> Age</td>
  <td> Sex</td>
</tr>
<tr>
  <td>Cantor, Georg</td>
  <td> 163</td>
  <td> M</td>
</tr>
</table>

Is Django for the frontend or backend?

Neither.

Django is a framework, not a language. Python is the language in which Django is written.

Django is a collection of Python libs allowing you to quickly and efficiently create a quality Web application, and is suitable for both frontend and backend.

However, Django is pretty famous for its "Django admin", an auto generated backend that allows you to manage your website in a blink for a lot of simple use cases without having to code much.

More precisely, for the front end, Django helps you with data selection, formatting, and display. It features URL management, a templating language, authentication mechanisms, cache hooks, and various navigation tools such as paginators.

For the backend, Django comes with an ORM that lets you manipulate your data source with ease, forms (an HTML independent implementation) to process user input and validate data and signals, and an implementation of the observer pattern. Plus a tons of use-case specific nifty little tools.

For the rest of the backend work Django doesn't help with, you just use regular Python. Business logic is a pretty broad term.

You probably want to know as well that Django comes with the concept of apps, a self contained pluggable Django library that solves a problem. The Django community is huge, and so there are numerous apps that do specific business logic that vanilla Django doesn't.

How to set ssh timeout?

If all else fails (including not having the timeout command) the concept in this shell script will work:

 #!/bin/bash
 set -u
 ssh $1 "sleep 10 ; uptime" > /tmp/outputfile 2>&1 & PIDssh=$!
 Count=0
 while test $Count -lt 5 && ps -p $PIDssh > /dev/null
 do
    echo -n .
    sleep 1
    Count=$((Count+1))
 done
 echo ""

 if ps -p $PIDssh > /dev/null
 then
    echo "ssh still running, killing it"
    kill -HUP $PIDssh
 else
    echo "Exited"
 fi

How to create a custom string representation for a class object?

Ignacio Vazquez-Abrams' approved answer is quite right. It is, however, from the Python 2 generation. An update for the now-current Python 3 would be:

class MC(type):
  def __repr__(self):
    return 'Wahaha!'

class C(object, metaclass=MC):
    pass

print(C)

If you want code that runs across both Python 2 and Python 3, the six module has you covered:

from __future__ import print_function
from six import with_metaclass

class MC(type):
  def __repr__(self):
    return 'Wahaha!'

class C(with_metaclass(MC)):
    pass

print(C)

Finally, if you have one class that you want to have a custom static repr, the class-based approach above works great. But if you have several, you'd have to generate a metaclass similar to MC for each, and that can get tiresome. In that case, taking your metaprogramming one step further and creating a metaclass factory makes things a bit cleaner:

from __future__ import print_function
from six import with_metaclass

def custom_class_repr(name):
    """
    Factory that returns custom metaclass with a class ``__repr__`` that
    returns ``name``.
    """
    return type('whatever', (type,), {'__repr__': lambda self: name})

class C(with_metaclass(custom_class_repr('Wahaha!'))): pass

class D(with_metaclass(custom_class_repr('Booyah!'))): pass

class E(with_metaclass(custom_class_repr('Gotcha!'))): pass

print(C, D, E)

prints:

Wahaha! Booyah! Gotcha!

Metaprogramming isn't something you generally need everyday—but when you need it, it really hits the spot!

recyclerview No adapter attached; skipping layout

Just put code inside onCreate() method

/* Like This*/

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.your_activity);

    recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
    layoutManager = new LinearLayoutManager(YourActivity.this);
    recyclerView.setLayoutManager(layoutManager);
    recyclerView.setHasFixedSize(true);
    mAdapter = new YourAdapter(YourModelClassObject);
    recyclerView.setAdapter(mAdapter);
}

How to do a SUM() inside a case statement in SQL server

You could use a Common Table Expression to create the SUM first, join it to the table, and then use the WHEN to to get the value from the CTE or the original table as necessary.

WITH PercentageOfTotal (Id, Percentage) 
AS 
(
    SELECT Id, (cnt / SUM(AreaId)) FROM dbo.MyTable GROUP BY Id
)
SELECT 
    CASE
        WHEN o.TotalType = 'Average' THEN r.avgscore
        WHEN o.TotalType = 'PercentOfTot' THEN pt.Percentage
        ELSE o.cnt
    END AS [displayscore]
FROM PercentageOfTotal pt
    JOIN dbo.MyTable t ON pt.Id = t.Id

What is logits, softmax and softmax_cross_entropy_with_logits?

tf.nn.softmax computes the forward propagation through a softmax layer. You use it during evaluation of the model when you compute the probabilities that the model outputs.

tf.nn.softmax_cross_entropy_with_logits computes the cost for a softmax layer. It is only used during training.

The logits are the unnormalized log probabilities output the model (the values output before the softmax normalization is applied to them).

$(document).ready not Working

One possibility, take a look:

<script language="javascript" type="text/javascript" src="./jquery-3.1.1.slim.min.js" />

vs

<script language="javascript" type="text/javascript" src="./jquery-3.1.1.slim.min.js"></script>

The first method is actually wrong, however the browser does not complain at all. You need to be sure that you are indeed closing the javascript tag in the proper way.

Which websocket library to use with Node.js?

Update: This answer is outdated as newer versions of libraries mentioned are released since then.

Socket.IO v0.9 is outdated and a bit buggy, and Engine.IO is the interim successor. Socket.IO v1.0 (which will be released soon) will use Engine.IO and be much better than v0.9. I'd recommend you to use Engine.IO until Socket.IO v1.0 is released.

"ws" does not support fallback, so if the client browser does not support websockets, it won't work, unlike Socket.IO and Engine.IO which uses long-polling etc if websockets are not available. However, "ws" seems like the fastest library at the moment.

See my article comparing Socket.IO, Engine.IO and Primus: https://medium.com/p/b63bfca0539

Google Maps v2 - set both my location and zoom in

Its a late answer but I think it will help. Use this method:

protected void zoomMapInitial(LatLng finalPlace, LatLng currenLoc) {
    try {
        int padding = 200; // Space (in px) between bounding box edges and view edges (applied to all four sides of the bounding box)
        LatLngBounds.Builder bc = new LatLngBounds.Builder();

        bc.include(finalPlace);
        bc.include(currenLoc);
        googleMap.moveCamera(CameraUpdateFactory.newLatLngBounds(bc.build(), padding));
    } catch (Exception e) {
        e.printStackTrace();
    }
}

Use this method after loading the map. Cheers!

How to get last items of a list in Python?

The last 9 elements can be read from left to right using numlist[-9:], or from right to left using numlist[:-10:-1], as you want.

>>> a=range(17)
>>> print a
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16]
>>> print a[-9:]
[8, 9, 10, 11, 12, 13, 14, 15, 16]
>>> print a[:-10:-1]
[16, 15, 14, 13, 12, 11, 10, 9, 8]

How can I switch to a tag/branch in hg?

Once you have cloned the repo, you have everything: you can then hg up branchname or hg up tagname to update your working copy.

UP: hg up is a shortcut of hg update, which also has hg checkout alias for people with git habits.

Retrieve version from maven pom.xml in code

Assuming you're using Java, you can:

  1. Create a .properties file in (most commonly) your src/main/resources directory (but in step 4 you could tell it to look elsewhere).

  2. Set the value of some property in your .properties file using the standard Maven property for project version:

    foo.bar=${project.version}
    
  3. In your Java code, load the value from the properties file as a resource from the classpath (google for copious examples of how to do this, but here's an example for starters).

  4. In Maven, enable resource filtering. This will cause Maven to copy that file into your output classes and translate the resource during that copy, interpreting the property. You can find some info here but you mostly just do this in your pom:

    <build>
      <resources>
        <resource>
          <directory>src/main/resources</directory>
          <filtering>true</filtering>
        </resource>
      </resources>   
    </build>
    

You can also get to other standard properties like project.name, project.description, or even arbitrary properties you put in your pom <properties>, etc. Resource filtering, combined with Maven profiles, can give you variable build behavior at build time. When you specify a profile at runtime with -PmyProfile, that can enable properties that then can show up in your build.

How do I add a .click() event to an image?

Enclose <img> in <a> tag.

<a href="http://www.google.com.pk"><img src="smiley.gif"></a>

it will open link on same tab, and if you want to open link on new tab then use target="_blank"

<a href="http://www.google.com.pk" target="_blank"><img src="smiley.gif"></a>

Definition of "downstream" and "upstream"

In terms of source control, you're "downstream" when you copy (clone, checkout, etc) from a repository. Information flowed "downstream" to you.

When you make changes, you usually want to send them back "upstream" so they make it into that repository so that everyone pulling from the same source is working with all the same changes. This is mostly a social issue of how everyone can coordinate their work rather than a technical requirement of source control. You want to get your changes into the main project so you're not tracking divergent lines of development.

Sometimes you'll read about package or release managers (the people, not the tool) talking about submitting changes to "upstream". That usually means they had to adjust the original sources so they could create a package for their system. They don't want to keep making those changes, so if they send them "upstream" to the original source, they shouldn't have to deal with the same issue in the next release.

Converting String to "Character" array in Java

I hope the code below will help you.

String s="Welcome to Java Programming";
char arr[]=s.toCharArray();
for(int i=0;i<arr.length;i++){
    System.out.println("Data at ["+i+"]="+arr[i]);
}

It's working and the output is:

Data at [0]=W
Data at [1]=e
Data at [2]=l
Data at [3]=c
Data at [4]=o
Data at [5]=m
Data at [6]=e
Data at [7]= 
Data at [8]=t
Data at [9]=o
Data at [10]= 
Data at [11]=J
Data at [12]=a
Data at [13]=v
Data at [14]=a
Data at [15]= 
Data at [16]=P
Data at [17]=r
Data at [18]=o
Data at [19]=g
Data at [20]=r
Data at [21]=a
Data at [22]=m
Data at [23]=m
Data at [24]=i
Data at [25]=n
Data at [26]=g

Select all 'tr' except the first one

Though the question has a decent answer already, I just want to stress that the :first-child tag goes on the item type that represents the children.

For example, in the code:

<div id"someDiv">
     <input id="someInput1" /> 
     <input id="someInput2" />
     <input id="someInput2" />
</div

If you want to affect only the second two elements with a margin, but not the first, you would do:

#someDiv > input {
     margin-top: 20px;
}
#someDiv > input:first-child{
     margin-top: 0px;
}

that is, since the inputs are the children, you would place first-child on the input portion of the selector.

ActionBarCompat: java.lang.IllegalStateException: You need to use a Theme.AppCompat

I encountered this error when I was trying to create a DialogBox when some action is taken inside the CustomAdapter class. This was not an Activity but an Adapter class. After 36 hrs of efforts and looking up for solutions, I came up with this.

Send the Activity as a parameter while calling the CustomAdapter.

CustomAdapter ca = new CustomAdapter(MyActivity.this,getApplicationContext(),records);

Define the variables in the custom Adapter.

Activity parentActivity;
Context context;

Call the constructor like this.

public CustomAdapter(Activity parentActivity,Context context,List<Record> records){
    this.parentActivity=parentActivity;
    this.context=context;
    this.records=records;
}

And finally when creating the dialog box inside the adapter class, do it like this.

AlertDialog ad = new AlertDialog.Builder(parentActivity).setTitle("Your title");

and so on..

I hope this helps you

Printing Exception Message in java

The output looks correct to me:

Invalid JavaScript code: sun.org.mozilla.javascript.internal.EvaluatorException: missing } after property list (<Unknown source>) in <Unknown source>; at line number 1

I think Invalid Javascript code: .. is the start of the exception message.

Normally the stacktrace isn't returned with the message:

try {
    throw new RuntimeException("hu?\ntrace-line1\ntrace-line2");
} catch (Exception e) {
    System.out.println(e.getMessage()); // prints "hu?"
}

So maybe the code you are calling catches an exception and rethrows a ScriptException. In this case maybe e.getCause().getMessage() can help you.

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

In Docker:

  1. go to Settings
  2. go to Docker Engine
  3. change experimental to true
  4. press Apply and Restart

.

Multiple aggregate functions in HAVING clause

Something like this?

HAVING COUNT(caseID) > 2
AND COUNT(caseID) < 4

SQL Server query - Selecting COUNT(*) with DISTINCT

try this:

SELECT
    COUNT(program_name) AS [Count],program_type AS [Type]
    FROM (SELECT DISTINCT program_name,program_type
              FROM cm_production 
              WHERE push_number=@push_number
         ) dt
    GROUP BY program_type

Creating random numbers with no duplicates

Your problem seems to reduce to choose k elements at random from a collection of n elements. The Collections.shuffle answer is thus correct, but as pointed out inefficient: its O(n).

Wikipedia: Fisher–Yates shuffle has a O(k) version when the array already exists. In your case, there is no array of elements and creating the array of elements could be very expensive, say if max were 10000000 instead of 20.

The shuffle algorithm involves initializing an array of size n where every element is equal to its index, picking k random numbers each number in a range with the max one less than the previous range, then swapping elements towards the end of the array.

You can do the same operation in O(k) time with a hashmap although I admit its kind of a pain. Note that this is only worthwhile if k is much less than n. (ie k ~ lg(n) or so), otherwise you should use the shuffle directly.

You will use your hashmap as an efficient representation of the backing array in the shuffle algorithm. Any element of the array that is equal to its index need not appear in the map. This allows you to represent an array of size n in constant time, there is no time spent initializing it.

  1. Pick k random numbers: the first is in the range 0 to n-1, the second 0 to n-2, the third 0 to n-3 and so on, thru n-k.

  2. Treat your random numbers as a set of swaps. The first random index swaps to the final position. The second random index swaps to the second to last position. However, instead of working against a backing array, work against your hashmap. Your hashmap will store every item that is out of position.

int getValue(i) { if (map.contains(i)) return map[i]; return i; } void setValue(i, val) { if (i == val) map.remove(i); else map[i] = val; } int[] chooseK(int n, int k) { for (int i = 0; i < k; i++) { int randomIndex = nextRandom(0, n - i); //(n - i is exclusive) int desiredIndex = n-i-1; int valAtRandom = getValue(randomIndex); int valAtDesired = getValue(desiredIndex); setValue(desiredIndex, valAtRandom); setValue(randomIndex, valAtDesired); } int[] output = new int[k]; for (int i = 0; i < k; i++) { output[i] = (getValue(n-i-1)); } return output; }

CSS strikethrough different color from text?

Blazemonger's reply (above or below) needs voting up - but I don't have enough points.

I wanted to add a grey bar across some 20px wide CSS round buttons to indicate "not available" and tweaked Blazemonger's css:

.round_btn:after {
    content:"";    /* required property */
    position: absolute;
    top: 6px;
    left: -1px;
    border-top: 6px solid rgba(170,170,170,0.65);
    height: 6px;
    width: 19px;
}

What's the best way to add a full screen background image in React Native

If you want to add a background image you can do so by using but first you have to import this from 'react-native' as follows:

import {ImageBackground} from 'react-native';

then:

    export default function App() {
    
    return (
        <View style={styles.body}>

            <ImageBackground source={require('./path/to/yourimage')} style={styles.backgroungImage}>
                <View style={styles.container}>Hello world!
                </View>
            </ImageBackground>
        </View>
    );
}

    const styles = StyleSheet.create({
    backgroungImage: {
    flex: 1,
    maxWidth: '100%',
  }
});

return in for loop or outside loop

Now someone told me that this is not very good programming because I use the return statement inside a loop and this would cause garbage collection to malfunction.

That's incorrect, and suggests you should treat other advice from that person with a degree of skepticism.

The mantra of "only have one return statement" (or more generally, only one exit point) is important in languages where you have to manage all resources yourself - that way you can make sure you put all your cleanup code in one place.

It's much less useful in Java: as soon as you know that you should return (and what the return value should be), just return. That way it's simpler to read - you don't have to take in any of the rest of the method to work out what else is going to happen (other than finally blocks).