Programs & Examples On #Rets

The Real Estate Transaction Standard (RETS) facilitates data transfer between partners in the real estate industry via XML/webservice calls. It is an improvement over the existing protocol/procedure called IDX (Internet Data exchange) which could mean HTTP webservices, CSV files from FTP, or in some cases via Telnet.

Kubernetes Pod fails with CrashLoopBackOff

Pod is not started due to problem coming after initialization of POD.

Check and use command to get docker container of pod

docker ps -a | grep private-reg

Output will be information of docker container with id.

See docker logs:

docker logs -f <container id>

How does the "view" method work in PyTorch?

Let's try to understand view by the following examples:

    a=torch.range(1,16)

print(a)

    tensor([ 1.,  2.,  3.,  4.,  5.,  6.,  7.,  8.,  9., 10., 11., 12., 13., 14.,
            15., 16.])

print(a.view(-1,2))

    tensor([[ 1.,  2.],
            [ 3.,  4.],
            [ 5.,  6.],
            [ 7.,  8.],
            [ 9., 10.],
            [11., 12.],
            [13., 14.],
            [15., 16.]])

print(a.view(2,-1,4))   #3d tensor

    tensor([[[ 1.,  2.,  3.,  4.],
             [ 5.,  6.,  7.,  8.]],

            [[ 9., 10., 11., 12.],
             [13., 14., 15., 16.]]])
print(a.view(2,-1,2))

    tensor([[[ 1.,  2.],
             [ 3.,  4.],
             [ 5.,  6.],
             [ 7.,  8.]],

            [[ 9., 10.],
             [11., 12.],
             [13., 14.],
             [15., 16.]]])

print(a.view(4,-1,2))

    tensor([[[ 1.,  2.],
             [ 3.,  4.]],

            [[ 5.,  6.],
             [ 7.,  8.]],

            [[ 9., 10.],
             [11., 12.]],

            [[13., 14.],
             [15., 16.]]])

-1 as an argument value is an easy way to compute the value of say x provided we know values of y, z or the other way round in case of 3d and for 2d again an easy way to compute the value of say x provided we know values of y or vice versa..

The term "Add-Migration" is not recognized

I had this problem and none of the previous solutions helped me. My problem was actually due to an outdated version of powershell on my Windows 7 machine - once I updated to powershell 5 it started working.

How to install and run Typescript locally in npm?

You can now use ts-node, which makes your life as simple as

npm install -D ts-node
npm install -D typescript

ts-node script.ts

How do I force Kubernetes to re-pull an image?

This answer aims to force an image pull in a situation where your node has already downloaded an image with the same name, therefore even though you push a new image to container registry, when you spin up some pods, your pod says "image already present".

For a case in Azure Container Registry (probably AWS and GCP also provides this):

  1. You can look to your Azure Container Registry and by checking the manifest creation date you can identify what image is the most recent one.

  2. Then, copy its digest hash (which has a format of sha256:xxx...xxx).

  3. You can scale down your current replica by running command below. Note that this will obviously stop your container and cause downtime.

kubectl scale --replicas=0 deployment <deployment-name> -n <namespace-name>
  1. Then you can get the copy of the deployment.yaml by running:
kubectl get deployments.apps <deployment-name> -o yaml > deployment.yaml
  1. Then change the line with image field from <image-name>:<tag> to <image-name>@sha256:xxx...xxx, save the file.

  2. Now you can scale up your replicas again. New image will be pulled with its unique digest.

Note: It is assumed that, imagePullPolicy: Always field is present in the container.

Multiline editing in Visual Studio Code

(Windows 10 pro x64) Here have some ways!

  1. Alt + click

  2. Alt + Ctrl + up/down

  3. Keybindings: Ctrl + click (??? it doesn't work!)

Enter image description here

No function matches the given name and argument types

In my particular case the function was actually missing. The error message is the same. I am using the Postgresql plugin PostGIS and I had to reinstall that for whatever reason.

How to solve error "Missing `secret_key_base` for 'production' environment" (Rails 4.1)

In my case, the problem was that config/master.key was not in version control, and I had created the project on a different computer.

The default .gitignore that Rails creates excludes this file. Since it's impossible to deploy without having this file, it needs to be in version control, in order to be able to deploy from any team member's computer.

Solution: remove the config/master.key line from .gitignore, commit the file from the computer where the project was created, and now you can git pull on the other computer and deploy from it.

People are saying not to commit some of these files to version control, without offering an alternative solution. As long as you're not working on an open source project, I see no reason not to commit everything that's required to run the project, including credentials.

How to add a downloaded .box file to Vagrant?

Try to change directory to where the .box is saved

Run vagrant box add my-box downloaded.box, this may work as it avoids absolute path (on Windows?).

invalid conversion from 'const char*' to 'char*'

Well, data.str().c_str() yields a char const* but your function Printfunc() wants to have char*s. Based on the name, it doesn't change the arguments but merely prints them and/or uses them to name a file, in which case you should probably fix your declaration to be

void Printfunc(int a, char const* loc, char const* stream)

The alternative might be to turn the char const* into a char* but fixing the declaration is preferable:

Printfunc(num, addr, const_cast<char*>(data.str().c_str()));

Printing out a linked list using toString

When the JVM tries to run your application, it calls your main method statically; something like this:

LinkedList.main();

That means there is no instance of your LinkedList class. In order to call your toString() method, you can create a new instance of your LinkedList class.

So the body of your main method should be like this:

public static void main(String[] args){
    // creating an instance of LinkedList class
    LinkedList ll = new LinkedList();

    // adding some data to the list
    ll.insertFront(1);
    ll.insertFront(2);
    ll.insertFront(3);
    ll.insertBack(4);

    System.out.println(ll.toString());
}

Working with time DURATION, not time of day

The best way I found to resolve this issue was by using a combination of the above. All my cells were entered as a Custom Format to only show "HH:MM" - if I entered in "4:06" (being 4 minutes and 6 seconds) the field would show the numbers I entered correctly - but the data itself would represent HH:MM in the background.

Fortunately time is based on factors of 60 (60 seconds = 60 minutes). So 7H:15M / 60 = 7M:15S - I hope you can see where this is going. Accordingly, if I take my 4:06 and divide by 60 when working with the data (eg. to total up my total time or average time across 100 cells I would use the normal SUM or AVERAGE formulas and then divide by 60 in the formula.

Example =(SUM(A1:A5))/60. If my data was across the 5 time tracking fields was the 4:06, 3:15, 9:12, 2:54, 7:38 (representing MM:SS for us, but the data in the background is actually HH:MM) then when I work out the sum of those 5 fields are, what I want should be 27M:05S but what shows instead is 1D:03H:05M:00S. As mentioned above, 1D:3H:5M divided by 60 = 27M:5S ... which is the sum I am looking for.

Further examples of this are: =(SUM(G:G))/60 and =(AVERAGE(B2:B90)/60) and =MIN(C:C) (this is a direct check so no /60 needed here!).

Note that your "formula" or "calculation" fields (average, total time, etc) MUST have the custom format of MM:SS once you have divided by 60 as Excel's default thinking is in HH:MM (hence this issue). Your data fields where you are entering in your times should need to be changed from "General" or "Number" format to the custom format of HH:MM.

This process is still a little bit cumbersome to use - but it does mean that your data entry is still entered in very easy and is "correctly" displayed on screen as 4:06 (which most people would view as minutes:seconds when under a "Minutes" header). Generally there will only be a couple of fields needing to be used for formulas such as "best time", "average time", "total time" etc when tracking times and they will not usually be changed once the formula is entered so this will be a "one off" process - I use this for my call tracking sheet at work to track "average call", "total call time for day".

PHP add elements to multidimensional array with array_push

if you want to add the data in the increment order inside your associative array you can do this:

$newdata =  array (
      'wpseo_title' => 'test',
      'wpseo_desc' => 'test',
      'wpseo_metakey' => 'test'
    );

// for recipe

$md_array["recipe_type"][] = $newdata;

//for cuisine

 $md_array["cuisine"][] = $newdata;

this will get added to the recipe or cuisine depending on what was the last index.

Array push is usually used in the array when you have sequential index: $arr[0] , $ar[1].. you cannot use it in associative array directly. But since your sub array is had this kind of index you can still use it like this

array_push($md_array["cuisine"],$newdata);

height: calc(100%) not working correctly in CSS

You don't need to calculate anything, and probably shouldn't:

<!DOCTYPE html>
<head>
<style type="text/css">
    body {background: blue; height:100%;}
    header {background: red; height: 20px; width:100%}
    h1 {font-size:1.2em; margin:0; padding:0; 
        height: 30px; font-weight: bold; background:yellow}
    .theCalcDiv {background-color:green; padding-bottom: 100%}
</style>
</head>
<body>
<header>Some nav stuff here</header>
<h1>This is the heading</h1>
<div class="theCalcDiv">This blocks needs to have a CSS calc() height of 100% - the height of the other elements.
</div>

I stuck it all together for brevity.

Simple way to understand Encapsulation and Abstraction

Abstraction is generalised term. i.e. Encapsulation is subset of Abstraction.

Abstraction is a powerful methodology to manage complex systems. Abstraction is managed by well-defined objects and their hierarchical classification.

For example a car in itself is a well-defined object, which is composed of several other smaller objects like a gearing system, steering mechanism, engine, which are again have their own subsystems. But for humans car is a one single object, which can be managed by the help of its subsystems, even if their inner details are unknown. Courtesy


Encapsulation: Wrapping up data member and method together into a single unit (i.e. Class) is called Encapsulation.

Encapsulation is like enclosing in a capsule. That is enclosing the related operations and data related to an object into that object.

Encapsulation is like your bag in which you can keep your pen, book etc. It means this is the property of encapsulating members and functions.

class Bag{
    book;
    pen;
    ReadBook();
}

Encapsulation means hiding the internal details of an object, i.e. how an object does something.

Encapsulation prevents clients from seeing its inside view, where the behaviour of the abstraction is implemented.

Encapsulation is a technique used to protect the information in an object from the other object.

Hide the data for security such as making the variables as private, and expose the property to access the private data which would be public.

So, when you access the property you can validate the data and set it. Courtesy

Using JSON POST Request

An example using jQuery is below. Hope this helps

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<title>My jQuery JSON Web Page</title>
<head>
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
<script type="text/javascript">

JSONTest = function() {

    var resultDiv = $("#resultDivContainer");

    $.ajax({
        url: "https://example.com/api/",
        type: "POST",
        data: { apiKey: "23462", method: "example", ip: "208.74.35.5" },
        dataType: "json",
        success: function (result) {
            switch (result) {
                case true:
                    processResponse(result);
                    break;
                default:
                    resultDiv.html(result);
            }
        },
        error: function (xhr, ajaxOptions, thrownError) {
        alert(xhr.status);
        alert(thrownError);
        }
    });
};

</script>
</head>
<body>

<h1>My jQuery JSON Web Page</h1>

<div id="resultDivContainer"></div>

<button type="button" onclick="JSONTest()">JSON</button>

</body>
</html> 

Firebug debug process

Firebug XHR debug process

How to escape indicator characters (i.e. : or - ) in YAML

If you're using @ConfigurationProperties with Spring Boot 2 to inject maps with keys that contain colons then you need an additional level of escaping using square brackets inside the quotes because spring only allows alphanumeric and '-' characters, stripping out the rest. Your new key would look like this:

"[8.11.32.120:8000]": GoogleMapsKeyforThisDomain

See this github issue for reference.

How to calculate distance from Wifi router using Signal Strength?

K = 32.44
FSPL = Ptx - CLtx + AGtx + AGrx - CLrx - Prx - FM
d = 10 ^ (( FSPL - K - 20 log10( f )) / 20 )

Here:

  • K - constant (32.44, when f in MHz and d in km, change to -27.55 when f in MHz and d in m)
  • FSPL - Free Space Path Loss
  • Ptx - transmitter power, dBm ( up to 20 dBm (100mW) )
  • CLtx, CLrx - cable loss at transmitter and receiver, dB ( 0, if no cables )
  • AGtx, AGrx - antenna gain at transmitter and receiver, dBi
  • Prx - receiver sensitivity, dBm ( down to -100 dBm (0.1pW) )
  • FM - fade margin, dB ( more than 14 dB (normal) or more than 22 dB (good))
  • f - signal frequency, MHz
  • d - distance, m or km (depends on value of K)

Note: there is an error in formulas from TP-Link support site (mising ^).

Substitute Prx with received signal strength to get a distance from WiFi AP.

Example: Ptx = 16 dBm, AGtx = 2 dBi, AGrx = 0, Prx = -51 dBm (received signal strength), CLtx = 0, CLrx = 0, f = 2442 MHz (7'th 802.11bgn channel), FM = 22. Result: FSPL = 47 dB, d = 2.1865 m

Note: FM (fade margin) seems to be irrelevant here, but I'm leaving it because of the original formula.

You should take into acount walls, table http://www.liveport.com/wifi-signal-attenuation may help.

Example: (previous data) + one wooden wall ( 5 dB, from the table ). Result: FSPL = FSPL - 5 dB = 44 dB, d = 1.548 m

Also please note, that antena gain dosn't add power - it describes the shape of radiation pattern (donut in case of omnidirectional antena, zeppelin in case of directional antenna, etc).

None of this takes into account signal reflections (don't have an idea how to do this). Probably noise is also missing. So this math may be good only for rough distance estimation.

rsync - mkstemp failed: Permission denied (13)

I had the same error while syncing files inside of a Docker container and the destination was a mounted volume (Docker for mac), I run rsync via su-exec <user>. I was able to resolve it by running rsync as root with -og flags (keep owner and group for destination files).

I'm still not sure what caused that issue, the destination permissions were OK (I run chown -R <user> for destination dir before rsync), perhaps somehow related to Docker for Mac slow filesystem.

How to debug Apache mod_rewrite

There's the htaccess tester.

It shows which conditions were tested for a certain URL, which ones met the criteria and which rules got executed.

It seems to have some glitches, though.

Troubleshooting BadImageFormatException

When building apps for 32-bit or 64-bit platform (My experience is with Visual Studio 2010), don't rely on the Configuration Manager to set the correct platform for the executable. Even if the CM has x86 selected for the application, check the project properties (Build tab): it might still say "Any CPU" there. And if you run an "Any CPU" executable on a 64-bit platform, it will run in 64-bit mode and refuse to load your accompanying DLLs that were built for the x86 platform.

What do \t and \b do?

\t is the tab character, and is doing exactly what you're anticipating based on the action of \b - it goes to the next tab stop, then gets decremented, and then goes to the next tab stop (which is in this case the same tab stop, because of the \b.

Why is JsonRequestBehavior needed?

You do not need it.

If your action has the HttpPost attribute, then you do not need to bother with setting the JsonRequestBehavior and use the overload without it. There is an overload for each method without the JsonRequestBehavior enum. Here they are:

Without JsonRequestBehavior

protected internal JsonResult Json(object data);
protected internal JsonResult Json(object data, string contentType);
protected internal virtual JsonResult Json(object data, string contentType, Encoding contentEncoding);

With JsonRequestBehavior

protected internal JsonResult Json(object data, JsonRequestBehavior behavior);
protected internal JsonResult Json(object data, string contentType, 
                                   JsonRequestBehavior behavior);
protected internal virtual JsonResult Json(object data, string contentType, 
    Encoding contentEncoding, JsonRequestBehavior behavior);

Ignore self-signed ssl cert using Jersey Client

Since I am new to stackoverflow and have lesser reputation to comment on others' answers, I am putting the solution suggested by Chris Salij with some modification which worked for me.

            SSLContext ctx = null;
            TrustManager[] trustAllCerts = new X509TrustManager[]{new X509TrustManager(){
                public X509Certificate[] getAcceptedIssuers(){return null;}
                public void checkClientTrusted(X509Certificate[] certs, String authType){}
                public void checkServerTrusted(X509Certificate[] certs, String authType){}
            }};
            try {
                ctx = SSLContext.getInstance("SSL");
                ctx.init(null, trustAllCerts, null);
            } catch (NoSuchAlgorithmException | KeyManagementException e) {
                LOGGER.info("Error loading ssl context {}", e.getMessage());
            }

            SSLContext.setDefault(ctx);

Using Sockets to send and receive data

I assume you are using TCP sockets for the client-server interaction? One way to send different types of data to the server and have it be able to differentiate between the two is to dedicate the first byte (or more if you have more than 256 types of messages) as some kind of identifier. If the first byte is one, then it is message A, if its 2, then its message B. One easy way to send this over the socket is to use DataOutputStream/DataInputStream:

Client:

Socket socket = ...; // Create and connect the socket
DataOutputStream dOut = new DataOutputStream(socket.getOutputStream());

// Send first message
dOut.writeByte(1);
dOut.writeUTF("This is the first type of message.");
dOut.flush(); // Send off the data

// Send the second message
dOut.writeByte(2);
dOut.writeUTF("This is the second type of message.");
dOut.flush(); // Send off the data

// Send the third message
dOut.writeByte(3);
dOut.writeUTF("This is the third type of message (Part 1).");
dOut.writeUTF("This is the third type of message (Part 2).");
dOut.flush(); // Send off the data

// Send the exit message
dOut.writeByte(-1);
dOut.flush();

dOut.close();

Server:

Socket socket = ... // Set up receive socket
DataInputStream dIn = new DataInputStream(socket.getInputStream());

boolean done = false;
while(!done) {
  byte messageType = dIn.readByte();

  switch(messageType)
  {
  case 1: // Type A
    System.out.println("Message A: " + dIn.readUTF());
    break;
  case 2: // Type B
    System.out.println("Message B: " + dIn.readUTF());
    break;
  case 3: // Type C
    System.out.println("Message C [1]: " + dIn.readUTF());
    System.out.println("Message C [2]: " + dIn.readUTF());
    break;
  default:
    done = true;
  }
}

dIn.close();

Obviously, you can send all kinds of data, not just bytes and strings (UTF).

Note that writeUTF writes a modified UTF-8 format, preceded by a length indicator of an unsigned two byte encoded integer giving you 2^16 - 1 = 65535 bytes to send. This makes it possible for readUTF to find the end of the encoded string. If you decide on your own record structure then you should make sure that the end and type of the record is either known or detectable.

Get a list of numbers as input from the user

num = int(input('Size of elements : '))
arr = list()

for i in range(num) :
  ele  = int(input())
  arr.append(ele)

print(arr)

What is "runtime"?

Run time exactly where your code comes into life and you can see lot of important thing your code do.

Runtime has a responsibility of allocating memory , freeing memory , using operating system's sub system like (File Services, IO Services.. Network Services etc.)

Your code will be called "WORKING IN THEORY" until you practically run your code. and Runtime is a friend which helps in achiving this.

PHP json_encode encoding numbers as strings

I also had the same problem processing data from the database. Basically the problem is that the type in the array to convert in json, is recognized by PHP as a string and not as integer. In my case I made a query that returns data from a DB column counting row. The PDO driver does not recognize the column as int, but as strings. I solved by performing a cast as int in the affected column.

What does asterisk * mean in Python?

I only have one thing to add that wasn't clear from the other answers (for completeness's sake).

You may also use the stars when calling the function. For example, say you have code like this:

>>> def foo(*args):
...     print(args)
...
>>> l = [1,2,3,4,5]

You can pass the list l into foo like so...

>>> foo(*l)
(1, 2, 3, 4, 5)

You can do the same for dictionaries...

>>> def foo(**argd):
...     print(argd)
...
>>> d = {'a' : 'b', 'c' : 'd'}
>>> foo(**d)
{'a': 'b', 'c': 'd'}

Interface vs Base class

When should I use an interface and when should I use a base class?

You should use interface if

  1. You have pure abstract methods and don't have non-abstract methods
  2. You don't have default implementation of non abstract methods (except for Java 8 language, where interface methods provides default implementation)
  3. If you are using Java 8, now interface will provide default implementation for some non-abstract methods. This will make interface more usable compared to abstract classes.

Have a look at this SE question for more details.

Should it always be an interface if I don't want to actually define a base implementation of the methods?

Yes. It's better and cleaner. Even if you have a base class with some abstract methods, let's base class extends abstract methods through interface. You can change interface in future without changing the base class.

Example in java:

abstract class PetBase implements IPet {
// Add all abstract methods in IPet interface and keep base class clean. 
   Base class will contain only non abstract methods and static methods.
}

If I have a Dog and Cat class. Why would I want to implement IPet instead of PetBase? I can understand having interfaces for ISheds or IBarks (IMakesNoise?), because those can be placed on a pet by pet basis, but I don't understand which to use for a generic Pet.

I prefer to have base class implement the interface.

 abstract class PetBase implements IPet {
 // Add all abstract methods in IPet
 }

 /*If ISheds,IBarks is common for Pets, your PetBase can implement ISheds,IBarks. 
  Respective implementations of PetBase can change the behaviour in their concrete classes*/

 abstract class PetBase implements IPet,ISheds,IBarks {
 // Add all abstract methods in respective interfaces
 }

Advantages:

  1. If I want to add one more abstract method in existing interfaces, I simple change interface without touching the abstract base class. If I want to change the contract, I will change interface & implementation classes without touching base class.

  2. You can provide immutability to base class through interface. Have a look at this article

Refer to this related SE question for more details:

How should I have explained the difference between an Interface and an Abstract class?

Inserting into Oracle and retrieving the generated sequence ID

You can do this with a single statement - assuming you are calling it from a JDBC-like connector with in/out parameters functionality:

insert into batch(batchid, batchname) 
values (batch_seq.nextval, 'new batch')
returning batchid into :l_batchid;

or, as a pl-sql script:

variable l_batchid number;

insert into batch(batchid, batchname) 
values (batch_seq.nextval, 'new batch')
returning batchid into :l_batchid;

select :l_batchid from dual;

get value from DataTable

You can try changing it to this:

If myTableData.Rows.Count > 0 Then
  For i As Integer = 0 To myTableData.Rows.Count - 1
    ''Dim DataType() As String = myTableData.Rows(i).Item(1)
    ListBox2.Items.Add(myTableData.Rows(i)(1))
  Next
End If

Note: Your loop needs to be one less than the row count since it's a zero-based index.

How to set my default shell on Mac?

Terminal.app > Preferences > General > Shells open with: > /bin/fish

  1. Open your terminal and press command+, (comma). This will open a preferences window.
  2. The first tab is 'General'.
  3. Find 'Shells open with' setting and choose 2nd option which needs complete path to the shell.
  4. Paste the link to your fish command, which generally is /usr/local/bin/fish.

See this screenshot where zsh is being set as default.

screenshot of entering <code>/bin/zsh</code> in Terminal.app preferences

I am using macOS Sierra. Also works in macOS Mojave.

Access a URL and read Data with R

base

read.csv without the url function just works fine. Probably I am missing something if Dirk Eddelbuettel included it in his answer:

ad <- read.csv("http://www-bcf.usc.edu/~gareth/ISL/Advertising.csv")
head(ad)

  X    TV radio newspaper sales
1 1 230.1  37.8      69.2  22.1
2 2  44.5  39.3      45.1  10.4
3 3  17.2  45.9      69.3   9.3
4 4 151.5  41.3      58.5  18.5
5 5 180.8  10.8      58.4  12.9
6 6   8.7  48.9      75.0   7.2

Another options using two popular packages:

data.table

library(data.table)
ad <- fread("http://www-bcf.usc.edu/~gareth/ISL/Advertising.csv")
head(ad)

V1    TV radio newspaper sales
1:  1 230.1  37.8      69.2  22.1
2:  2  44.5  39.3      45.1  10.4
3:  3  17.2  45.9      69.3   9.3
4:  4 151.5  41.3      58.5  18.5
5:  5 180.8  10.8      58.4  12.9
6:  6   8.7  48.9      75.0   7.2

readr

library(readr)
ad <- read_csv("http://www-bcf.usc.edu/~gareth/ISL/Advertising.csv")
head(ad)

# A tibble: 6 x 5
     X1    TV radio newspaper sales
  <int> <dbl> <dbl>     <dbl> <dbl>
1     1 230.1  37.8      69.2  22.1
2     2  44.5  39.3      45.1  10.4
3     3  17.2  45.9      69.3   9.3
4     4 151.5  41.3      58.5  18.5
5     5 180.8  10.8      58.4  12.9
6     6   8.7  48.9      75.0   7.2

"Bitmap too large to be uploaded into a texture"

Instead of spending hours upon hours trying to write/debug all this downsampling code manually, why not use Picasso? It was made for dealing with bitmaps of all types and/or sizes.

I have used this single line of code to remove my "bitmap too large...." problem:

Picasso.load(resourceId).fit().centerCrop().into(imageView);

org.json.simple.JSONArray cannot be cast to org.json.simple.JSONObject

JSONObject obj=(JSONObject)JSONValue.parse(content); 
JSONArray arr=(JSONArray)obj.get("units"); 
System.out.println(arr.get(1));  //this will print {"id":42,...sities ..}

@cyberz is right but explain it reverse

MySQL direct INSERT INTO with WHERE clause

you can use UPDATE command.

UPDATE table_name SET name=@name, email=@email, phone=@phone WHERE client_id=@client_id

How to use Console.WriteLine in ASP.NET (C#) during debug?

You shouldn't launch as an IIS server. check your launch setting, make sure it switched to your project name( change this name in your launchSettings.json file ), not the IIS.

enter image description here

How do I get and set Environment variables in C#?

I could be able to update the environment variable by using the following

string EnvPath = System.Environment.GetEnvironmentVariable("PATH", EnvironmentVariableTarget.Machine) ?? string.Empty;
if (!string.IsNullOrEmpty(EnvPath) && !EnvPath .EndsWith(";"))
    EnvPath = EnvPath + ';';
EnvPath = EnvPath + @"C:\Test";
Environment.SetEnvironmentVariable("PATH", EnvPath , EnvironmentVariableTarget.Machine);

hardcoded string "row three", should use @string resource

You must create them under strings.xml

<string name="close">Close</string>    

You must replace and reference like this

android:text="@string/close"/>

Do not use @strings even though the XML file says strings.xml or else it will not work.

"Missing return statement" within if / for / while

That's because the function needs to return a value. Imagine what happens if you execute myMethod() and it doesn't go into if(condition) what would your function returns? The compiler needs to know what to return in every possible execution of your function

Checking Java documentation:

Definition: If a method declaration has a return type then there must be a return statement at the end of the method. If the return statement is not there the missing return statement error is thrown.

This error is also thrown if the method does not have a return type and has not been declared using void (i.e., it was mistakenly omitted).

You can do to solve your problem:

public String myMethod()
{
    String result = null;
    if(condition)
    {
       result = x;
    }
    return result;
}

How to center a button within a div?

Responsive way to center your button in a div:

<div 
    style="display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 2rem;">
    <button type="button" style="height: 10%; width: 20%;">hello</button>
</div>

Can I have onScrollListener for a ScrollView?

you can define a custom ScrollView class, & add an interface be called when scrolling like this:

public class ScrollChangeListenerScrollView extends HorizontalScrollView {


private MyScrollListener mMyScrollListener;

public ScrollChangeListenerScrollView(Context context) {
    super(context);
}

public ScrollChangeListenerScrollView(Context context, AttributeSet attrs) {
    super(context, attrs);
}

public ScrollChangeListenerScrollView(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
}


public void setOnMyScrollListener(MyScrollListener myScrollListener){
    this.mMyScrollListener = myScrollListener;
}


@Override
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
    super.onScrollChanged(l, t, oldl, oldt);
    if(mMyScrollListener!=null){
        mMyScrollListener.onScrollChange(this,l,t,oldl,oldt);
    }

}

public interface MyScrollListener {
    void onScrollChange(View view,int scrollX,int scrollY,int oldScrollX, int oldScrollY);
}

}

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

I have the same issue with the ".index()" method on lists. I have no issue with the fact that it throws an exception but I strongly disagree with the fact that it's a non-descriptive ValueError. I could understand if it would've been an IndexError, though.

I can see why returning "-1" would be an issue too because it's a valid index in Python. But realistically, I never expect a ".index()" method to return a negative number.

Here goes a one liner (ok, it's a rather long line ...), goes through the list exactly once and returns "None" if the item isn't found. It would be trivial to rewrite it to return -1, should you so desire.

indexOf = lambda list, thing: \
            reduce(lambda acc, (idx, elem): \
                   idx if (acc is None) and elem == thing else acc, list, None)

How to use:

>>> indexOf([1,2,3], 4)
>>>
>>> indexOf([1,2,3], 1)
0
>>>

Spring MVC: How to perform validation?

Put this bean in your configuration class.

 @Bean
  public Validator localValidatorFactoryBean() {
    return new LocalValidatorFactoryBean();
  }

and then You can use

 <T> BindingResult validate(T t) {
    DataBinder binder = new DataBinder(t);
    binder.setValidator(validator);
    binder.validate();
    return binder.getBindingResult();
}

for validating a bean manually. Then You will get all result in BindingResult and you can retrieve from there.

Delete files older than 3 months old in a directory using .NET

The GetLastAccessTime property on the System.IO.File class should help.

Browser back button handling

You can also add hash when page is loading:

location.hash = "noBack";

Then just handle location hash change to add another hash:

$(window).on('hashchange', function() {
    location.hash = "noBack";
});

That makes hash always present and back button tries to remove hash at first. Hash is then added again by "hashchange" handler - so page would never actually can be changed to previous one.

Fast and Lean PDF Viewer for iPhone / iPad / iOS - tips and hints?

I have build such kind of application using approximatively the same approach except :

  • I cache the generated image on the disk and always generate two to three images in advance in a separate thread.
  • I don't overlay with a UIImage but instead draw the image in the layer when zooming is 1. Those tiles will be released automatically when memory warnings are issued.

Whenever the user start zooming, I acquire the CGPDFPage and render it using the appropriate CTM. The code in - (void)drawLayer: (CALayer*)layer inContext: (CGContextRef) context is like :

CGAffineTransform currentCTM = CGContextGetCTM(context);    
if (currentCTM.a == 1.0 && baseImage) {
    //Calculate ideal scale
    CGFloat scaleForWidth = baseImage.size.width/self.bounds.size.width;
    CGFloat scaleForHeight = baseImage.size.height/self.bounds.size.height; 
    CGFloat imageScaleFactor = MAX(scaleForWidth, scaleForHeight);

    CGSize imageSize = CGSizeMake(baseImage.size.width/imageScaleFactor, baseImage.size.height/imageScaleFactor);
    CGRect imageRect = CGRectMake((self.bounds.size.width-imageSize.width)/2, (self.bounds.size.height-imageSize.height)/2, imageSize.width, imageSize.height);
    CGContextDrawImage(context, imageRect, [baseImage CGImage]);
} else {
    @synchronized(issue) { 
        CGPDFPageRef pdfPage = CGPDFDocumentGetPage(issue.pdfDoc, pageIndex+1);
        pdfToPageTransform = CGPDFPageGetDrawingTransform(pdfPage, kCGPDFMediaBox, layer.bounds, 0, true);
        CGContextConcatCTM(context, pdfToPageTransform);    
        CGContextDrawPDFPage(context, pdfPage);
    }
}

issue is the object containg the CGPDFDocumentRef. I synchronize the part where I access the pdfDoc property because I release it and recreate it when receiving memoryWarnings. It seems that the CGPDFDocumentRef object do some internal caching that I did not find how to get rid of.

How can I create a Java 8 LocalDate from a long Epoch time in Milliseconds?

Timezones and stuff aside, a very simple alternative to new Date(startDateLong) could be LocalDate.ofEpochDay(startDateLong / 86400000L)

CodeIgniter: Load controller within controller

If you're interested, there's a well-established package out there that you can add to your Codeigniter project that will handle this:

https://bitbucket.org/wiredesignz/codeigniter-modular-extensions-hmvc/

Modular Extensions makes the CodeIgniter PHP framework modular. Modules are groups of independent components, typically model, controller and view, arranged in an application modules sub-directory, that can be dropped into other CodeIgniter applications.

OK, so the big change is that now you'd be using a modular structure - but to me this is desirable. I have used CI for about 3 years now, and can't imagine life without Modular Extensions.

Now, here's the part that deals with directly calling controllers for rendering view partials:

// Using a Module as a view partial from within a view is as easy as writing:
<?php echo modules::run('module/controller/method', $param1, $params2); ?>

That's all there is to it. I typically use this for loading little "widgets" like:

  • Event calendars
  • List of latest news articles
  • Newsletter signup forms
  • Polls

Typically I build a "widget" controller for each module and use it only for this purpose.

Your question was also one of my first questions when I started with Codeigniter. I hope this helps you out, even though it may be a bit more than you were looking for. I've been using MX ever since and haven't looked back.

Make sure to read the docs and check out the multitude of information regarding this package on the Codeigniter forums. Enjoy!

CSS set li indent

padding-left is what controls the indentation of ul not margin-left.

Compare: Here's setting padding-left to 0, notice all the indentation disappears.

_x000D_
_x000D_
ul {
  padding-left: 0;
}
_x000D_
<ul>
  <li>section a
    <ul>
      <li>one</li>
      <li>two</li>
      <li>three</li>
    </ul>
  </li>
</ul>
<ul>
  <li>section b
    <ul>
      <li>one</li>
      <li>two</li>
      <li>three</li>
    </ul>
  </li>
</ul>
_x000D_
_x000D_
_x000D_

and here's setting margin-left to 0px. Notice the indentation does NOT change.

_x000D_
_x000D_
ul {
  margin-left: 0;
}
_x000D_
<ul>
  <li>section a
    <ul>
      <li>one</li>
      <li>two</li>
      <li>three</li>
    </ul>
  </li>
</ul>
<ul>
  <li>section b
    <ul>
      <li>one</li>
      <li>two</li>
      <li>three</li>
    </ul>
  </li>
</ul>
_x000D_
_x000D_
_x000D_

A server with the specified hostname could not be found

I restarted my MacBook Pro and then I build again, the error was fixed.

Visual Studio: How to show Overloads in IntelliSense?

Tested only on Visual Studio 2010.

Place your cursor within the (), press Ctrl+K, then P.

Now navigate by pressing the  ?  / ?   arrow keys.

Command line for looking at specific port

As noted elsewhere: use netstat, with appropriate switches, and then filter the results with find[str]

Most basic:

netstat -an | find ":N"

or

netstat -a -n | find ":N"

To find a foreign port you could use:

netstat -an | findstr ":N[^:]*$"

To find a local port you might use:

netstat -an | findstr ":N.*:[^:]*$"

Where N is the port number you are interested in.

-n ensures all ports will be numerical, i.e. not returned as translated to service names.

-a will ensure you search all connections (TCP, UDP, listening...)

In the find string you must include the colon, as the port qualifier, otherwise the number may match either local or foreign addresses.

You can further narrow narrow the search using other netstat switches as necessary...

Further reading (^0^)

netstat /?

find /?

findstr /?

CSS fill remaining width

Include your image in the searchBar div, it will do the task for you

<div id="searchBar">
    <img src="img/logo.png" />                
    <input type="text" />
</div>

How to use readline() method in Java?

In summary: I would be careful as to what code you copy. It is possible you are copying code which happens to work, rather than well chosen code.

In intnumber, parseInt is used and in floatnumber valueOf is used why so?

There is no good reason I can see. It's an inconsistent use of the APIs as you suspect.


Java is case sensitive, and there isn't any Readline() method. Perhaps you mean readLine().

DataInputStream.readLine() is deprecated in favour of using BufferedReader.readLine();

However, for your case, I would use the Scanner class.

Scanner sc = new Scanner(System.in);
int intNum = sc.nextInt();
float floatNum = sc.nextFloat();

If you want to know what a class does I suggest you have a quick look at the Javadoc.

did you register the component correctly? For recursive components, make sure to provide the "name" option

One of the mistakes is setting components as array instead of object!

This is wrong:

<script>
import ChildComponent from './ChildComponent.vue';
export default {
  name: 'ParentComponent',
  components: [
    ChildComponent
  ],
  props: {
    ...
  }
};
</script>

This is correct:

<script>
import ChildComponent from './ChildComponent.vue';
export default {
  name: 'ParentComponent',
  components: {
    ChildComponent
  },
  props: {
    ...
  }
};
</script>

Note: for components that use other ("child") components, you must also specify a components field!

Is there a Newline constant defined in Java like Environment.Newline in C#?

As of Java 7 (and Android API level 19):

System.lineSeparator()

Documentation: Java Platform SE 7


For older versions of Java, use:

System.getProperty("line.separator");

See https://java.sun.com/docs/books/tutorial/essential/environment/sysprop.html for other properties.

How to grep, excluding some patterns?

You can use grep -P (perl regex) supported negative lookbehind:

grep -P '(?<!g)loom\b' ~/projects/**/trunk/src/**/*.@(h|cpp)

I added \b for word boundaries.

How to pass arguments to addEventListener listener function?

There is a special variable inside all functions: arguments. You can pass your parameters as anonymous parameters and access them (by order) through the arguments variable.

Example:

var someVar = some_other_function();
someObj.addEventListener("click", function(someVar){
    some_function(arguments[0]);
}, false);

How to check if activity is in foreground or in visible background?

Save a flag if you are paused or resumed. If you are resumed it means you are in the foreground

boolean  isResumed = false;

@Override
public void onPause() {
  super.onPause();    
  isResumed = false;
}

@Override
public void onResume() {
  super.onResume();    
  isResumed = true;
}

private void finishIfForeground() {
  if (isResumed) {
    finish();
  }
}

Warning: push.default is unset; its implicit value is changing in Git 2.0

I realize this is an old post but as I just ran into the same issue and had trouble finding the answer I thought I'd add a bit.

So @hammar's answer is correct. Using push.default simple is, in a way, like configuring tracking on your branches so you don't need to specify remotes and branches when pushing and pulling. The matching option will push all branches to their corresponding counterparts on the default remote (which is the first one that was set up unless you've configured your repo otherwise).

One thing I hope others find useful in the future is that I was running Git 1.8 on OS X Mountain Lion and never saw this error. Upgrading to Mavericks is what suddenly made it show up (running git --version will show git version 1.8.3.4 (Apple Git-47) which I'd never seen until the update to the OS.

How to run jenkins as a different user

you can integrate to LDAP or AD as well. It works well.

Nginx subdomain configuration

You could move the common parts to another configuration file and include from both server contexts. This should work:

server {
  listen 80;
  server_name server1.example;
  ...
  include /etc/nginx/include.d/your-common-stuff.conf;
}

server {
  listen 80;
  server_name another-one.example;
  ...
  include /etc/nginx/include.d/your-common-stuff.conf;
}

Edit: Here's an example that's actually copied from my running server. I configure my basic server settings in /etc/nginx/sites-enabled (normal stuff for nginx on Ubuntu/Debian). For example, my main server bunkus.org's configuration file is /etc/nginx/sites-enabled and it looks like this:

server {
  listen   80 default_server;
  listen   [2a01:4f8:120:3105::101:1]:80 default_server;

  include /etc/nginx/include.d/all-common;
  include /etc/nginx/include.d/bunkus.org-common;
  include /etc/nginx/include.d/bunkus.org-80;
}

server {
  listen   443 default_server;
  listen   [2a01:4f8:120:3105::101:1]:443 default_server;

  include /etc/nginx/include.d/all-common;
  include /etc/nginx/include.d/ssl-common;
  include /etc/nginx/include.d/bunkus.org-common;
  include /etc/nginx/include.d/bunkus.org-443;
}

As an example here's the /etc/nginx/include.d/all-common file that's included from both server contexts:

index index.html index.htm index.php .dirindex.php;
try_files $uri $uri/ =404;

location ~ /\.ht {
  deny all;
}

location = /favicon.ico {
  log_not_found off;
  access_log off;
}

location ~ /(README|ChangeLog)$ {
  types { }
  default_type text/plain;
}

Does Hibernate create tables in the database automatically

Hibernate can create a table, hibernate sequence and tables used for many-to-many mapping on your behalf but you have to explicitly configure it by calling setProperty("hibernate.hbm2ddl.auto", "create") of the Configuration object. By Default, it just validates the schema with DB and fails if anything not already exists by giving error "ORA-00942: table or view does not exist".

If you do above configuration then order of performed actions will be:- a) Drop all tables and sequence and do not give an error if they are not already present. b) create all table and sequence c) alter tables with constraints d) insert data into it.

I can't install intel HAXM

I faced this problem.I got the solution too.It will work.

Step 1: Go to your BIOS settings and check that INTERNET VIRTUAL TECHNOLOGY is Enabled or Disabled.

And make sure HYPER V is disabled. To disable it : a)Go to Control Panel b)Click on Programs(Uninstall a Program) c)Then click on Turn Windows features on or off , then look for HYPER-V and untick it. And Restart. If disabled then enable it.

Step 2: Try to install Intel HAXM now and restart. If It shows same problem again. go to Step 3.

Step 3: You have to disable Digitally Signed Enforcement. To disable it permanently you have to make sure that Secure Boot option is disabled in your system.

How to check ?

Answer is given in the following link. I found it in Internet.[Thanks whoever made that blog]

link : http://www.windowspasswordsrecovery.com/win8-tips/how-to-disable-uefi-secure-boot-in-windows-8-1-8.html

Step 4: Now restart again.

To disable driver signature enforcement permanently in Windows 10, you need to do the following:

1.Open an elevated command prompt instance.
2.Type/paste the following text:

     `bcdedit.exe /set nointegritychecks on`

or Windows 10

     `bcedit.exe -set loadoptions DISABLE_INTEGRITY_CHECKS`

Windows 10 disable driver signature enforcement

Restart Windows 10.

*If you somehow want to enable it again:

1.Type/paste the following text:

     `bcdedit.exe /set nointegritychecks off`

How can I use ":" as an AWK field separator?

AWK works as a text interpreter that goes linewise for the whole document and that goes fieldwise for each line. Thus $1, $2...$n are references to the fields of each line ($1 is the first field, $2 is the second field, and so on...).

You can define a field separator by using the "-F" switch under the command line or within two brackets with "FS=...".

Now consider the answer of Jürgen:

echo "1: " | awk -F  ":" '/1/ {print $1}'

Above the field, boundaries are set by ":" so we have two fields $1 which is "1" and $2 which is the empty space. After comes the regular expression "/1/" that instructs the filter to output the first field only when the interpreter stumbles upon a line containing such an expression (I mean 1).

The output of the "echo" command is one line that contains "1", so the filter will work...

When dealing with the following example:

echo "1: " | awk '/1/ -F ":" {print $1}'

The syntax is messy and the interpreter chose to ignore the part F ":" and switches to the default field splitter which is the empty space, thus outputting "1:" as the first field and there will be not a second field!

The answer of Jürgen contains the good syntax...

How do I create a user with the same privileges as root in MySQL/MariaDB?

% mysql --user=root mysql
CREATE USER 'monty'@'localhost' IDENTIFIED BY 'some_pass';
GRANT ALL PRIVILEGES ON *.* TO 'monty'@'localhost' WITH GRANT OPTION;
CREATE USER 'monty'@'%' IDENTIFIED BY 'some_pass';
GRANT ALL PRIVILEGES ON *.* TO 'monty'@'%' WITH GRANT OPTION;
CREATE USER 'admin'@'localhost';
GRANT RELOAD,PROCESS ON *.* TO 'admin'@'localhost';
CREATE USER 'dummy'@'localhost';
FLUSH PRIVILEGES;

Position: absolute and parent height?

Here is my workaround,
In your example you can add a third element with "same styles" of .one & .two elements, but without the absolute position and with hidden visibility:

HTML

<article>
   <div class="one"></div>
   <div class="two"></div>
   <div class="three"></div>
</article>

CSS

.three{
    height: 30px;
    z-index: -1;
    visibility: hidden;
}

A fast way to delete all rows of a datatable at once

Here we have same question. You can use the following code:

SqlConnection con = new SqlConnection();
con.ConnectionString = ConfigurationManager.ConnectionStrings["yourconnectionstringnamehere"].ConnectionString;
con.Open();
SqlCommand com = new SqlCommand();
com.Connection = con;
com.CommandText = "DELETE FROM [tablenamehere]";
SqlDataReader data = com.ExecuteReader();
con.Close();

But before you need to import following code to your project:

using System.Configuration;
using System.Data.SqlClient;

This is the specific part of the code that can delete all rows is a table:

DELETE FROM [tablenamehere]

This must be your table name:tablenamehere - This can delete all rows in table: DELETE FROM

Replace Line Breaks in a String C#

Use replace with Environment.NewLine

myString = myString.Replace(System.Environment.NewLine, "replacement text"); //add a line terminating ;

As mentioned in other posts, if the string comes from another environment (OS) then you'd need to replace that particular environments implementation of new line control characters.

Run a script in Dockerfile

RUN and ENTRYPOINT are two different ways to execute a script.

RUN means it creates an intermediate container, runs the script and freeze the new state of that container in a new intermediate image. The script won't be run after that: your final image is supposed to reflect the result of that script.

ENTRYPOINT means your image (which has not executed the script yet) will create a container, and runs that script.

In both cases, the script needs to be added, and a RUN chmod +x /bootstrap.sh is a good idea.

It should also start with a shebang (like #!/bin/sh)

Considering your script (bootstrap.sh: a couple of git config --global commands), it would be best to RUN that script once in your Dockerfile, but making sure to use the right user (the global git config file is %HOME%/.gitconfig, which by default is the /root one)

Add to your Dockerfile:

RUN /bootstrap.sh

Then, when running a container, check the content of /root/.gitconfig to confirm the script was run.

How to get position of a certain element in strings vector, to use it as an index in ints vector?

If you want an index, you can use std::find in combination with std::distance.

auto it = std::find(Names.begin(), Names.end(), old_name_);
if (it == Names.end())
{
  // name not in vector
} else
{
  auto index = std::distance(Names.begin(), it);
}

Invalid length for a Base-64 char array

My initial guess without knowing the data would be that the UserNameToVerify is not a multiple of 4 in length. Check out the FromBase64String on msdn.

// Ok
byte[] b1 = Convert.FromBase64String("CoolDude");
// Exception
byte[] b2 = Convert.FromBase64String("MyMan");

Get the index of the object inside an array, matching a condition

function findIndexByKeyValue(_array, key, value) {
    for (var i = 0; i < _array.length; i++) { 
        if (_array[i][key] == value) {
            return i;
        }
    }
    return -1;
}
var a = [
    {prop1:"abc",prop2:"qwe"},
    {prop1:"bnmb",prop2:"yutu"},
    {prop1:"zxvz",prop2:"qwrq"}];
var index = findIndexByKeyValue(a, 'prop2', 'yutu');
console.log(index);

What version of Java is running in Eclipse?

Don't about the code but you can figure it out like this way :

Go into the 'window' tab then preferences->java->Installed JREs. You can add your own JRE(1.7 or 1.5 etc) also.

For changing the compliance level window->preferences->java->compiler. C Change the compliance level.

Multiplying across in a numpy array

For those lost souls on google, using numpy.expand_dims then numpy.repeat will work, and will also work in higher dimensional cases (i.e. multiplying a shape (10, 12, 3) by a (10, 12)).

>>> import numpy
>>> a = numpy.array([[1,2,3],[4,5,6],[7,8,9]])
>>> b = numpy.array([0,1,2])
>>> b0 = numpy.expand_dims(b, axis = 0)
>>> b0 = numpy.repeat(b0, a.shape[0], axis = 0)
>>> b1 = numpy.expand_dims(b, axis = 1)
>>> b1 = numpy.repeat(b1, a.shape[1], axis = 1)
>>> a*b0
array([[ 0,  2,  6],
   [ 0,  5, 12],
   [ 0,  8, 18]])
>>> a*b1
array([[ 0,  0,  0],
   [ 4,  5,  6],
   [14, 16, 18]])

Git push error pre-receive hook declined

Please check if JIRA status in "In Development". For me , it was not , when i changed jira status to "In Development", it worked for me.

HowTo Generate List of SQL Server Jobs and their owners

If you don't have access to sysjobs table (someone elses server etc) you might be have or be allowed access to sysjobs_view

SELECT *
 from  msdb..sysjobs_view s 
 left join master.sys.syslogins l on s.owner_sid = l.sid

or

SELECT *, SUSER_SNAME(s.owner_sid) AS owner
 from  msdb..sysjobs_view s 

Is it possible to insert HTML content in XML document?

You can include HTML content. One possibility is encoding it in BASE64 as you have mentioned.

Another might be using CDATA tags.

Example using CDATA:

<xml>
    <title>Your HTML title</title>
    <htmlData><![CDATA[<html>
        <head>
            <script/>
        </head>
        <body>
        Your HTML's body
        </body>
        </html>
     ]]>
    </htmlData>
</xml>

Please note:

CDATA's opening character sequence: <![CDATA[

CDATA's closing character sequence: ]]>

Count unique values with pandas per groups

You need nunique:

df = df.groupby('domain')['ID'].nunique()

print (df)
domain
'facebook.com'    1
'google.com'      1
'twitter.com'     2
'vk.com'          3
Name: ID, dtype: int64

If you need to strip ' characters:

df = df.ID.groupby([df.domain.str.strip("'")]).nunique()
print (df)
domain
facebook.com    1
google.com      1
twitter.com     2
vk.com          3
Name: ID, dtype: int64

Or as Jon Clements commented:

df.groupby(df.domain.str.strip("'"))['ID'].nunique()

You can retain the column name like this:

df = df.groupby(by='domain', as_index=False).agg({'ID': pd.Series.nunique})
print(df)
    domain  ID
0       fb   1
1      ggl   1
2  twitter   2
3       vk   3

The difference is that nunique() returns a Series and agg() returns a DataFrame.

How can I see the size of files and directories in linux?

You have to differenciate between file size and disk usage. The main difference between the two comes from the fact that files are "cut into pieces" and stored in blocks.

Modern block size is 4KiB, so files will use disk space multiple of 4KiB, regardless of how small they are.

If you use the command stat you can see both figures side by side.

stat file.c

If you want a more compact view for a directory, you can use ls -ls, which will give you usage in 1KiB units.

ls -ls dir

Also du will give you real disk usage, in 1KiB units, or dutree with the -u flag.

Example: usage of a 1 byte file

$ echo "" > file.c

$ ls -l file.c
-rw-r--r-- 1 nacho nacho 1 Apr 30 20:42 file.c

$ ls -ls file.c
4 -rw-r--r-- 1 nacho nacho 1 Apr 30 20:42 file.c

$ du file.c
4 file.c

$ dutree file.c
[ file.c 1 B ]

$ dutree -u file.c
[ file.c 4.00 KiB ]

$ stat file.c
 File: file.c
 Size: 1 Blocks: 8 IO Block: 4096 regular file
Device: 2fh/47d Inode: 2185244 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 1000/ nacho) Gid: ( 1000/ nacho)
Access: 2018-04-30 20:41:58.002124411 +0200
Modify: 2018-04-30 20:42:24.835458383 +0200
Change: 2018-04-30 20:42:24.835458383 +0200
 Birth: -

In addition, in modern filesystems we can have snapshots, sparse files (files with holes in them) that further complicate the situation.

You can see more details in this article: understanding file size in Linux

How to specify table's height such that a vertical scroll bar appears?

Try using the overflow CSS property. There are also separate properties to define the behaviour of just horizontal overflow (overflow-x) and vertical overflow (overflow-y).

Since you only want the vertical scroll, try this:

table {
  height: 500px;
  overflow-y: scroll;
}

EDIT:

Apparently <table> elements don't respect the overflow property. This appears to be because <table> elements are not rendered as display: block by default (they actually have their own display type). You can force the overflow property to work by setting the <table> element to be a block type:

table {
  display: block;
  height: 500px;
  overflow-y: scroll;
}

Note that this will cause the element to have 100% width, so if you don't want it to take up the entire horizontal width of the page, you need to specify an explicit width for the element as well.

Is it possible to find out the users who have checked out my project on GitHub?

If by "checked out" you mean people who have cloned your project, then no it is not possible. You don't even need to be a GitHub user to clone a repository, so it would be infeasible to track this.

Generate a random date between two other dates

What do you need the random number for? Usually (depending on the language) you can get the number of seconds/milliseconds from the Epoch from a date. So for a randomd date between startDate and endDate you could do:

  1. compute the time in ms between startDate and endDate (endDate.toMilliseconds() - startDate.toMilliseconds())
  2. generate a number between 0 and the number you obtained in 1
  3. generate a new Date with time offset = startDate.toMilliseconds() + number obtained in 2

How do I add a newline to a TextView in Android?

One way of doing this is using Html tags::

txtTitlevalue.setText(Html.fromHtml("Line1"+"<br>"+"Line2" + " <br>"+"Line3"));

How to reset sequence in postgres and fill id column with new data?

Inspired by the other answers here, I created an SQL function to do a sequence migration. The function moves a primary key sequence to a new contiguous sequence starting with any value (>= 1) either inside or outside the existing sequence range.

I explain here how I used this function in a migration of two databases with the same schema but different values into one database.

First, the function (which prints the generated SQL commands so that it is clear what is actually happening):

CREATE OR REPLACE FUNCTION migrate_pkey_sequence
  ( arg_table      text
  , arg_column     text
  , arg_sequence   text
  , arg_next_value bigint  -- Must be >= 1
  )
RETURNS int AS $$
DECLARE
  result int;
  curr_value bigint = arg_next_value - 1;
  update_column1 text := format
    ( 'UPDATE %I SET %I = nextval(%L) + %s'
    , arg_table
    , arg_column
    , arg_sequence
    , curr_value
    );
  alter_sequence text := format
    ( 'ALTER SEQUENCE %I RESTART WITH %s'
    , arg_sequence
    , arg_next_value
    );
  update_column2 text := format
    ( 'UPDATE %I SET %I = DEFAULT'
    , arg_table
    , arg_column
    );
  select_max_column text := format
    ( 'SELECT coalesce(max(%I), %s) + 1 AS nextval FROM %I'
    , arg_column
    , curr_value
    , arg_table
    );
BEGIN
  -- Print the SQL command before executing it.
  RAISE INFO '%', update_column1;
  EXECUTE update_column1;
  RAISE INFO '%', alter_sequence;
  EXECUTE alter_sequence;
  RAISE INFO '%', update_column2;
  EXECUTE update_column2;
  EXECUTE select_max_column INTO result;
  RETURN result;
END $$ LANGUAGE plpgsql;

The function migrate_pkey_sequence takes the following arguments:

  1. arg_table: table name (e.g. 'example')
  2. arg_column: primary key column name (e.g. 'id')
  3. arg_sequence: sequence name (e.g. 'example_id_seq')
  4. arg_next_value: next value for the column after migration

It performs the following operations:

  1. Move the primary key values to a free range. I assume that nextval('example_id_seq') follows max(id) and that the sequence starts with 1. This also handles the case where arg_next_value > max(id).
  2. Move the primary key values to the contiguous range starting with arg_next_value. The order of key values are preserved but holes in the range are not preserved.
  3. Print the next value that would follow in the sequence. This is useful if you want to migrate the columns of another table and merge with this one.

To demonstrate, we use a sequence and table defined as follows (e.g. using psql):

# CREATE SEQUENCE example_id_seq
  START WITH 1
  INCREMENT BY 1
  NO MINVALUE
  NO MAXVALUE
  CACHE 1;
# CREATE TABLE example
  ( id bigint NOT NULL DEFAULT nextval('example_id_seq'::regclass)
  );

Then, we insert some values (starting, for example, at 3):

# ALTER SEQUENCE example_id_seq RESTART WITH 3;
# INSERT INTO example VALUES (DEFAULT), (DEFAULT), (DEFAULT);
-- id: 3, 4, 5

Finally, we migrate the example.id values to start with 1.

# SELECT migrate_pkey_sequence('example', 'id', 'example_id_seq', 1);
INFO:  00000: UPDATE example SET id = nextval('example_id_seq') + 0
INFO:  00000: ALTER SEQUENCE example_id_seq RESTART WITH 1
INFO:  00000: UPDATE example SET id = DEFAULT
 migrate_pkey_sequence
-----------------------
                     4
(1 row)

The result:

# SELECT * FROM example;
 id
----
  1
  2
  3
(3 rows)

How to check if $_GET is empty?

i guess the simplest way which doesn't require any operators is

if($_GET){
//do something if $_GET is set 
} 
if(!$_GET){
//do something if $_GET is NOT set 
} 

How to remove all event handlers from an event

I hated any complete solutions shown here, I did a mix and tested now, worked for any event handler:

public class MyMain()
    public void MyMethod() {
        AnotherClass.TheEventHandler += DoSomeThing;
    }

    private void DoSomething(object sender, EventArgs e) {
        Debug.WriteLine("I did something");
        AnotherClass.ClearAllDelegatesOfTheEventHandler();
    }

}

public static class AnotherClass {

    public static event EventHandler TheEventHandler;

    public static void ClearAllDelegatesOfTheEventHandler() {

        foreach (Delegate d in TheEventHandler.GetInvocationList())
        {
            TheEventHandler -= (EventHandler)d;
        }
    }
}

Easy! Thanks for Stephen Punak.

I used it because I use a generic local method to remove the delegates and the local method was called after different cases, when different delegates are setted.

Modifying local variable from inside lambda

Use a wrapper

Any kind of wrapper is good.

With Java 8+, use either an AtomicInteger:

AtomicInteger ordinal = new AtomicInteger(0);
list.forEach(s -> {
  s.setOrdinal(ordinal.getAndIncrement());
});

... or an array:

int[] ordinal = { 0 };
list.forEach(s -> {
  s.setOrdinal(ordinal[0]++);
});

With Java 10+:

var wrapper = new Object(){ int ordinal = 0; };
list.forEach(s -> {
  s.setOrdinal(wrapper.ordinal++);
});

Note: be very careful if you use a parallel stream. You might not end up with the expected result. Other solutions like Stuart's might be more adapted for those cases.

For types other than int

Of course, this is still valid for types other than int. You only need to change the wrapping type to an AtomicReference or an array of that type. For instance, if you use a String, just do the following:

AtomicReference<String> value = new AtomicReference<>();
list.forEach(s -> {
  value.set("blah");
});

Use an array:

String[] value = { null };
list.forEach(s-> {
  value[0] = "blah";
});

Or with Java 10+:

var wrapper = new Object(){ String value; };
list.forEach(s->{
  wrapper.value = "blah";
});

Property [title] does not exist on this collection instance

When you're using get() you get a collection. In this case you need to iterate over it to get properties:

@foreach ($collection as $object)
    {{ $object->title }}
@endforeach

Or you could just get one of objects by it's index:

{{ $collection[0]->title }}

Or get first object from collection:

{{ $collection->first() }}

When you're using find() or first() you get an object, so you can get properties with simple:

{{ $object->title }}

ReactJS - Add custom event listener to component

I recommend using React.createRef() and ref=this.elementRef to get the DOM element reference instead of ReactDOM.findDOMNode(this). This way you can get the reference to the DOM element as an instance variable.

import React, { Component } from 'react';
import ReactDOM from 'react-dom';

class MenuItem extends Component {

  constructor(props) {
    super(props);

    this.elementRef = React.createRef();
  }

  handleNVFocus = event => {
      console.log('Focused: ' + this.props.menuItem.caption.toUpperCase());
  }
    
  componentDidMount() {
    this.elementRef.addEventListener('nv-focus', this.handleNVFocus);
  }

  componentWillUnmount() {
    this.elementRef.removeEventListener('nv-focus', this.handleNVFocus);
  }

  render() {
    return (
      <element ref={this.elementRef} />
    )
  }

}

export default MenuItem;

Counting inversions in an array

Maximum number of inversions possible for a list of size n could be generalized by an expression:

maxPossibleInversions = (n * (n-1) ) / 2

So for an array of size 6 maximum possible inversions will equal 15.

To achieve a complexity of n logn we could piggy back the inversion algorithm on merge sort.

Here are the generalized steps:

  • Split the array into two
  • Call the mergeSort routine. If the element in the left subarray is greater than the element in right sub array make inversionCount += leftSubArray.length

That's it!

This is a simple example, I made using Javascript:

var arr = [6,5,4,3,2,1]; // Sample input array

var inversionCount = 0;

function mergeSort(arr) {
    if(arr.length == 1)
        return arr;

    if(arr.length > 1) {
        let breakpoint = Math.ceil((arr.length/2));
        // Left list starts with 0, breakpoint-1
        let leftList = arr.slice(0,breakpoint);
        // Right list starts with breakpoint, length-1
        let rightList = arr.slice(breakpoint,arr.length);

        // Make a recursive call
        leftList = mergeSort(leftList);
        rightList = mergeSort(rightList);

        var a = merge(leftList,rightList);
        return a;
    }
}

function merge(leftList,rightList) {
    let result = [];
    while(leftList.length && rightList.length) {
        /**
         * The shift() method removes the first element from an array
         * and returns that element. This method changes the length
         * of the array.
         */
        if(leftList[0] <= rightList[0]) {
            result.push(leftList.shift());
        }else{
            inversionCount += leftList.length;
            result.push(rightList.shift());
        }
    }

    while(leftList.length)
        result.push(leftList.shift());

    while(rightList.length)
        result.push(rightList.shift());

    console.log(result);
    return result;
}

mergeSort(arr);
console.log('Number of inversions: ' + inversionCount);

Get current URL path in PHP

<?php
function current_url()
{
    $url      = "http://" . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];
    $validURL = str_replace("&", "&amp", $url);
    return $validURL;
}
//echo "page URL is : ".current_url();

$offer_url = current_url();

?>



<?php

if ($offer_url == "checking url name") {
?> <p> hi this is manip5595 </p>

<?php
}
?>

How to avoid using Select in Excel VBA

IMHO use of .select comes from people, who like me started learning VBA by necessity through recording macros and then modifying the code without realizing that .select and subsequent selection is just an unnecessary middle-men.

.select can be avoided, as many posted already, by directly working with the already existing objects, which allows various indirect referencing like calculating i and j in a complex way and then editing cell(i,j), etc.

Otherwise, there is nothing implicitly wrong with .select itself and you can find uses for this easily, e.g. I have a spreadsheet that I populate with date, activate macro that does some magic with it and exports it in an acceptable format on a separate sheet, which, however, requires some final manual (unpredictable) inputs into an adjacent cell. So here comes the moment for .select that saves me that additional mouse movement and click.

How to recursively list all the files in a directory in C#?

Directory.GetFiles("C:\\", "*.*", SearchOption.AllDirectories)

How to create JSON Object using String?

If you use the gson.JsonObject you can have something like that:

import com.google.gson.JsonObject;
import com.google.gson.JsonParser;

String jsonString = "{'test1':'value1','test2':{'id':0,'name':'testName'}}"
JsonObject jsonObject = (JsonObject) jsonParser.parse(jsonString)

Submit form and stay on same page?

When you hit on the submit button, the page is sent to the server. If you want to send it async, you can do it with ajax.

Calling a function on bootstrap modal open

You can use belw code for show and hide bootstrap model.

$('#my-model').on('shown.bs.modal', function (e) {
  // do something here...
})

and if you want to hide model then you can use below code.

$('#my-model').on('hidden.bs.modal', function() {
    // do something here...
});

I hope this answer is useful for your project.

1114 (HY000): The table is full

we had: SQLSTATE[HY000]: General error: 1114 The table 'catalog_product_index_price_bundle_sel_tmp' is full

solved by:

edit config of db:

nano /etc/my.cnf

tmp_table_size=256M max_heap_table_size=256M

  • restart db

Add UIPickerView & a Button in Action sheet - How?

To add to marcio's awesome solution, dismissActionSheet: can be implemented as follows.

  1. Add an ActionSheet object to your .h file, synthesize it and reference it in your .m file.
  2. Add this method to your code.

    - (void)dismissActionSheet:(id)sender{
      [_actionSheet dismissWithClickedButtonIndex:0 animated:YES];
      [_myButton setTitle:@"new title"]; //set to selected text if wanted
    }
    

pandas create new column based on values from other columns / apply a function of multiple columns, row-wise

Since this is the first Google result for 'pandas new column from others', here's a simple example:

import pandas as pd

# make a simple dataframe
df = pd.DataFrame({'a':[1,2], 'b':[3,4]})
df
#    a  b
# 0  1  3
# 1  2  4

# create an unattached column with an index
df.apply(lambda row: row.a + row.b, axis=1)
# 0    4
# 1    6

# do same but attach it to the dataframe
df['c'] = df.apply(lambda row: row.a + row.b, axis=1)
df
#    a  b  c
# 0  1  3  4
# 1  2  4  6

If you get the SettingWithCopyWarning you can do it this way also:

fn = lambda row: row.a + row.b # define a function for the new column
col = df.apply(fn, axis=1) # get column data with an index
df = df.assign(c=col.values) # assign values to column 'c'

Source: https://stackoverflow.com/a/12555510/243392

And if your column name includes spaces you can use syntax like this:

df = df.assign(**{'some column name': col.values})

And here's the documentation for apply, and assign.

pandas loc vs. iloc vs. at vs. iat?

loc: only work on index
iloc: work on position
at: get scalar values. It's a very fast loc
iat: Get scalar values. It's a very fast iloc

Also,

at and iat are meant to access a scalar, that is, a single element in the dataframe, while loc and iloc are ments to access several elements at the same time, potentially to perform vectorized operations.

http://pyciencia.blogspot.com/2015/05/obtener-y-filtrar-datos-de-un-dataframe.html

Python sys.argv lists and indexes

In a nutshell, sys.argv is a list of the words that appear in the command used to run the program. The first word (first element of the list) is the name of the program, and the rest of the elements of the list are any arguments provided. In most computer languages (including Python), lists are indexed from zero, meaning that the first element in the list (in this case, the program name) is sys.argv[0], and the second element (first argument, if there is one) is sys.argv[1], etc.

The test len(sys.argv) >= 2 simply checks wither the list has a length greater than or equal to 2, which will be the case if there was at least one argument provided to the program.

Create an ArrayList with multiple object types?

You can use Object for storing any type of value for e.g. int, float, String, class objects, or any other java objects, since it is the root of all the class. For e.g.

  1. Declaring a class

    class Person {
    public int personId;
    public String personName;
    
    public int getPersonId() {
        return personId;
    }
    
    public void setPersonId(int personId) {
        this.personId = personId;
    }
    
    public String getPersonName() {
        return personName;
    }
    
    public void setPersonName(String personName) {
        this.personName = personName;
    }}
    
  2. main function code, which creates the new person object, int, float, and string type, and then is added to the List, and iterated using for loop. Each object is identified, and then the value is printed.

        Person p = new Person();
    p.setPersonId(1);
    p.setPersonName("Tom");
    
    List<Object> lstObject = new ArrayList<Object>();
    lstObject.add(1232);
    lstObject.add("String");
    lstObject.add(122.212f);
    lstObject.add(p);
    
    for (Object obj : lstObject) {
        if (obj.getClass() == String.class) {
            System.out.println("I found a string :- " + obj);
        }
        if (obj.getClass() == Integer.class) {
            System.out.println("I found an int :- " + obj);
        }
        if (obj.getClass() == Float.class) {
            System.out.println("I found a float :- " + obj);
        }
        if (obj.getClass() == Person.class) {
            Person person = (Person) obj;
            System.out.println("I found a person object");
            System.out.println("Person Id :- " + person.getPersonId());
            System.out.println("Person Name :- " + person.getPersonName());
        }
    }
    

You can find more information on the object class on this link Object in java

How do you hide the Address bar in Google Chrome for Chrome Apps?

2016-05-04-03:59A - Windows 7 - Google Chrome [Version 50.0.2661.94]

wanted this done for a 'YouTube Pop-out Player' without Chrome Address / Toolbar or Bookmarks Bar; solution ended up being a small edit of MarkHu's answer (because of new updates, i guess?)

Go to the page you want altered, select Chrome Toolbar's 'Hamburger button' (3 horizontal lines).

From there: More tools > Add to desktop... > Open as window (tick box) > Add (button).

... and, simply open your page from the new desktop shortcut, adjust as needed, and enjoy!

how to insert value into DataGridView Cell?

For Some Reason I could Not add Numbers(in string Format) to the DataGridView But This Worked For Me Hope it help someone!

//dataGridView1.Rows[RowCount].Cells[0].Value = FEString3;//This was not adding Stringed Numbers like "1","2","3"....
DataGridViewCell NewCell = new DataGridViewTextBoxCell();//Create New Cell
NewCell.Value = FEString3;//Set Cell Value
DataGridViewRow NewRow = new DataGridViewRow();//Create New Row
NewRow.Cells.Add(NewCell);//Add Cell to Row
dataGridView1.Rows.Add(NewRow);//Add Row To Datagrid

Extracting first n columns of a numpy matrix

I know this is quite an old question -

A = [[1, 2, 3],
     [4, 5, 6],
     [7, 8, 9]]

Let's say, you want to extract the first 2 rows and first 3 columns

A_NEW = A[0:2, 0:3]
A_NEW = [[1, 2, 3],
         [4, 5, 6]]

Understanding the syntax

A_NEW = A[start_index_row : stop_index_row, 
          start_index_column : stop_index_column)]

If one wants row 2 and column 2 and 3

A_NEW = A[1:2, 1:3]

Reference the numpy indexing and slicing article - Indexing & Slicing

using batch echo with special characters

the escape character ^ also did not work for me. The single quotes worked for me (using ansible scripting)

shell: echo  '{{ jobid.content }}'

output:

 {
    "changed": true,
    "cmd": "echo  '<response status=\"success\" code=\"19\"><result><msg><line>query job enqueued with jobid 14447</line></msg><job>14447</job></result></response>'",
    "delta": "0:00:00.004943",
    "end": "2020-07-31 08:45:05.645672",
    "invocation": {
        "module_args": {
            "_raw_params": "echo  '<response status=\"success\" code=\"19\"><result><msg><line>query job enqueued with jobid 14447</line></msg><job>14447</job></result></response>'",
            "_uses_shell": true,
            "argv": null,
            "chdir": null,
            "creates": null,
            "executable": null,
            "removes": null,
            "stdin": null,
            "stdin_add_newline": true,
            "strip_empty_ends": true,
            "warn": true
        }
    },
    "rc": 0,
    "start": "2020-07-31 08:45:05.640729",
    "stderr": "",
    "stderr_lines": [],
    "stdout": "<response status=\"success\" code=\"19\"><result><msg><line>query job enqueued with jobid 14447</line></msg><job>14447</job></result></response>",
    "stdout_lines": [
        "<response status=\"success\" code=\"19\"><result><msg><line>query job enqueued with jobid 14447</line></msg><job>14447</job></result></response>"
    ]

Query an XDocument for elements by name at any depth

I am using XPathSelectElements extension method which works in the same way to XmlDocument.SelectNodes method:

using System;
using System.Xml.Linq;
using System.Xml.XPath; // for XPathSelectElements

namespace testconsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            XDocument xdoc = XDocument.Parse(
                @"<root>
                    <child>
                        <name>john</name>
                    </child>
                    <child>
                        <name>fred</name>
                    </child>
                    <child>
                        <name>mark</name>
                    </child>
                 </root>");

            foreach (var childElem in xdoc.XPathSelectElements("//child"))
            {
                string childName = childElem.Element("name").Value;
                Console.WriteLine(childName);
            }
        }
    }
}

What's the difference between size_t and int in C++?

size_t is the type used to represent sizes (as its names implies). Its platform (and even potentially implementation) dependent, and should be used only for this purpose. Obviously, representing a size, size_t is unsigned. Many stdlib functions, including malloc, sizeof and various string operation functions use size_t as a datatype.

An int is signed by default, and even though its size is also platform dependant, it will be a fixed 32bits on most modern machine (and though size_t is 64 bits on 64-bits architecture, int remain 32bits long on those architectures).

To summarize : use size_t to represent the size of an object and int (or long) in other cases.

.mp4 file not playing in chrome

After running into the same issue - here're some of my thoughts:

  • due to Chrome removing support for h264, on some machines, mp4 videos encoded with it will either not work (throwing an Parser error when viewing under Firebug/Network tab - consistent with issue submitted here), or crash the browser, depending upon the encoding settings
  • it isn't consistent - it entirely depends upon the codecs installed on the computer - while I didn't encounter this issue on my machine, we did have one in the office where the issue occurred (and thus we used this one for testing)
  • it might to do with Quicktime / divX settings (the machine in question had an older version of Quicktime than my native one - we didn't want to loose our testing pc though, so we didn't update it).

As it affects only Chrome (other browsers work fine with VideoForEverybody solution) the solution I've used is:

for every mp4 file, create a Theora encoded mp4 file (example.mp4 -> example_c.mp4) apply following js:

if (window.chrome)
    $("[type=video\\\/mp4]").each(function()
    {
        $(this).attr('src', $(this).attr('src').replace(".mp4", "_c.mp4"));
    });

Unfortunately it's a bad Chrome hack, but hey, at least it works.

Source: user: eithedog

This also can help: chrome could play html5 mp4 video but html5test said chrome did not support mp4 video codec

Also check your version of crome here: html5test

Anaconda / Python: Change Anaconda Prompt User Path

If you want to access folder you specified using Anaconda Prompt, try typing

cd C:\Users\u354590

How to pretty-print a numpy.array without scientific notation and with given precision?

Yet another option is to use the decimal module:

import numpy as np
from decimal import *

arr = np.array([  56.83,  385.3 ,    6.65,  126.63,   85.76,  192.72,  112.81, 10.55])
arr2 = [str(Decimal(i).quantize(Decimal('.01'))) for i in arr]

# ['56.83', '385.30', '6.65', '126.63', '85.76', '192.72', '112.81', '10.55']

Is floating point math broken?

Floating point numbers are represented, at the hardware level, as fractions of binary numbers (base 2). For example, the decimal fraction:

0.125

has the value 1/10 + 2/100 + 5/1000 and, in the same way, the binary fraction:

0.001

has the value 0/2 + 0/4 + 1/8. These two fractions have the same value, the only difference is that the first is a decimal fraction, the second is a binary fraction.

Unfortunately, most decimal fractions cannot have exact representation in binary fractions. Therefore, in general, the floating point numbers you give are only approximated to binary fractions to be stored in the machine.

The problem is easier to approach in base 10. Take for example, the fraction 1/3. You can approximate it to a decimal fraction:

0.3

or better,

0.33

or better,

0.333

etc. No matter how many decimal places you write, the result is never exactly 1/3, but it is an estimate that always comes closer.

Likewise, no matter how many base 2 decimal places you use, the decimal value 0.1 cannot be represented exactly as a binary fraction. In base 2, 1/10 is the following periodic number:

0.0001100110011001100110011001100110011001100110011 ...

Stop at any finite amount of bits, and you'll get an approximation.

For Python, on a typical machine, 53 bits are used for the precision of a float, so the value stored when you enter the decimal 0.1 is the binary fraction.

0.00011001100110011001100110011001100110011001100110011010

which is close, but not exactly equal, to 1/10.

It's easy to forget that the stored value is an approximation of the original decimal fraction, due to the way floats are displayed in the interpreter. Python only displays a decimal approximation of the value stored in binary. If Python were to output the true decimal value of the binary approximation stored for 0.1, it would output:

>>> 0.1
0.1000000000000000055511151231257827021181583404541015625

This is a lot more decimal places than most people would expect, so Python displays a rounded value to improve readability:

>>> 0.1
0.1

It is important to understand that in reality this is an illusion: the stored value is not exactly 1/10, it is simply on the display that the stored value is rounded. This becomes evident as soon as you perform arithmetic operations with these values:

>>> 0.1 + 0.2
0.30000000000000004

This behavior is inherent to the very nature of the machine's floating-point representation: it is not a bug in Python, nor is it a bug in your code. You can observe the same type of behavior in all other languages ??that use hardware support for calculating floating point numbers (although some languages ??do not make the difference visible by default, or not in all display modes).

Another surprise is inherent in this one. For example, if you try to round the value 2.675 to two decimal places, you will get

>>> round (2.675, 2)
2.67

The documentation for the round() primitive indicates that it rounds to the nearest value away from zero. Since the decimal fraction is exactly halfway between 2.67 and 2.68, you should expect to get (a binary approximation of) 2.68. This is not the case, however, because when the decimal fraction 2.675 is converted to a float, it is stored by an approximation whose exact value is :

2.67499999999999982236431605997495353221893310546875

Since the approximation is slightly closer to 2.67 than 2.68, the rounding is down.

If you are in a situation where rounding decimal numbers halfway down matters, you should use the decimal module. By the way, the decimal module also provides a convenient way to "see" the exact value stored for any float.

>>> from decimal import Decimal
>>> Decimal (2.675)
>>> Decimal ('2.67499999999999982236431605997495353221893310546875')

Another consequence of the fact that 0.1 is not exactly stored in 1/10 is that the sum of ten values ??of 0.1 does not give 1.0 either:

>>> sum = 0.0
>>> for i in range (10):
... sum + = 0.1
...>>> sum
0.9999999999999999

The arithmetic of binary floating point numbers holds many such surprises. The problem with "0.1" is explained in detail below, in the section "Representation errors". See The Perils of Floating Point for a more complete list of such surprises.

It is true that there is no simple answer, however do not be overly suspicious of floating virtula numbers! Errors, in Python, in floating-point number operations are due to the underlying hardware, and on most machines are no more than 1 in 2 ** 53 per operation. This is more than necessary for most tasks, but you should keep in mind that these are not decimal operations, and every operation on floating point numbers may suffer from a new error.

Although pathological cases exist, for most common use cases you will get the expected result at the end by simply rounding up to the number of decimal places you want on the display. For fine control over how floats are displayed, see String Formatting Syntax for the formatting specifications of the str.format () method.

This part of the answer explains in detail the example of "0.1" and shows how you can perform an exact analysis of this type of case on your own. We assume that you are familiar with the binary representation of floating point numbers.The term Representation error means that most decimal fractions cannot be represented exactly in binary. This is the main reason why Python (or Perl, C, C ++, Java, Fortran, and many others) usually doesn't display the exact result in decimal:

>>> 0.1 + 0.2
0.30000000000000004

Why ? 1/10 and 2/10 are not representable exactly in binary fractions. However, all machines today (July 2010) follow the IEEE-754 standard for the arithmetic of floating point numbers. and most platforms use an "IEEE-754 double precision" to represent Python floats. Double precision IEEE-754 uses 53 bits of precision, so on reading the computer tries to convert 0.1 to the nearest fraction of the form J / 2 ** N with J an integer of exactly 53 bits. Rewrite :

1/10 ~ = J / (2 ** N)

in :

J ~ = 2 ** N / 10

remembering that J is exactly 53 bits (so> = 2 ** 52 but <2 ** 53), the best possible value for N is 56:

>>> 2 ** 52
4503599627370496
>>> 2 ** 53
9007199254740992
>>> 2 ** 56/10
7205759403792793

So 56 is the only possible value for N which leaves exactly 53 bits for J. The best possible value for J is therefore this quotient, rounded:

>>> q, r = divmod (2 ** 56, 10)
>>> r
6

Since the carry is greater than half of 10, the best approximation is obtained by rounding up:

>>> q + 1
7205759403792794

Therefore the best possible approximation for 1/10 in "IEEE-754 double precision" is this above 2 ** 56, that is:

7205759403792794/72057594037927936

Note that since the rounding was done upward, the result is actually slightly greater than 1/10; if we hadn't rounded up, the quotient would have been slightly less than 1/10. But in no case is it exactly 1/10!

So the computer never "sees" 1/10: what it sees is the exact fraction given above, the best approximation using the double precision floating point numbers from the "" IEEE-754 ":

>>>. 1 * 2 ** 56
7205759403792794.0

If we multiply this fraction by 10 ** 30, we can observe the values ??of its 30 decimal places of strong weight.

>>> 7205759403792794 * 10 ** 30 // 2 ** 56
100000000000000005551115123125L

meaning that the exact value stored in the computer is approximately equal to the decimal value 0.100000000000000005551115123125. In versions prior to Python 2.7 and Python 3.1, Python rounded these values ??to 17 significant decimal places, displaying “0.10000000000000001”. In current versions of Python, the displayed value is the value whose fraction is as short as possible while giving exactly the same representation when converted back to binary, simply displaying “0.1”.

Delete all local git branches

If you want to keep master, develop and all remote branches. Delete all local branches which are not present on Github anymore.

$ git fetch --prune

$ git branch | grep -v "origin" | grep -v "develop" | grep -v "master" | xargs git branch -D

1] It will delete remote refs that are no longer in use on the remote repository.

2] This will get list of all your branches. Remove branch containing master, develop or origin (remote branches) from the list. Delete all branches in list.

Warning - This deletes your own local branches as well. So do this when you have merged your branch and doing a cleanup after merge, delete.

How to truncate string using SQL server

You can also use the Cast() operation :

 Declare @name varchar(100);
set @name='....';
Select Cast(@name as varchar(10)) as new_name

compareTo with primitives -> Integer / int

If you are using java 8, you can create Comparator by this method:

Comparator.comparingInt(i -> i);

if you would like to compare with reversed order:

Comparator.comparingInt(i -> -i);

Editing legend (text) labels in ggplot

The tutorial @Henrik mentioned is an excellent resource for learning how to create plots with the ggplot2 package.

An example with your data:

# transforming the data from wide to long
library(reshape2)
dfm <- melt(df, id = "TY")

# creating a scatterplot
ggplot(data = dfm, aes(x = TY, y = value, color = variable)) + 
  geom_point(size=5) +
  labs(title = "Temperatures\n", x = "TY [°C]", y = "Txxx", color = "Legend Title\n") +
  scale_color_manual(labels = c("T999", "T888"), values = c("blue", "red")) +
  theme_bw() +
  theme(axis.text.x = element_text(size = 14), axis.title.x = element_text(size = 16),
        axis.text.y = element_text(size = 14), axis.title.y = element_text(size = 16),
        plot.title = element_text(size = 20, face = "bold", color = "darkgreen"))

this results in:

enter image description here

As mentioned by @user2739472 in the comments: If you only want to change the legend text labels and not the colours from ggplot's default palette, you can use scale_color_hue(labels = c("T999", "T888")) instead of scale_color_manual().

AngularJS passing data to $http.get request

Solution for those who are interested in sending params and headers in GET request

$http.get('https://www.your-website.com/api/users.json', {
        params:  {page: 1, limit: 100, sort: 'name', direction: 'desc'},
        headers: {'Authorization': 'Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ=='}
    }
)
.then(function(response) {
    // Request completed successfully
}, function(x) {
    // Request error
});

Complete service example will look like this

var mainApp = angular.module("mainApp", []);

mainApp.service('UserService', function($http, $q){

   this.getUsers = function(page = 1, limit = 100, sort = 'id', direction = 'desc') {

        var dfrd = $q.defer();
        $http.get('https://www.your-website.com/api/users.json', 
            {
                params:{page: page, limit: limit, sort: sort, direction: direction},
                headers: {Authorization: 'Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ=='}
            }
        )
        .then(function(response) {
            if ( response.data.success == true ) { 

            } else {

            }
        }, function(x) {

            dfrd.reject(true);
        });
        return dfrd.promise;
   }

});

How to insert pandas dataframe via mysqldb into database?

df.to_sql(name = "owner", con= db_connection, schema = 'aws', if_exists='replace', index = >True, index_label='id')

CSS: On hover show and hide different div's at the same time?

if the other div is sibling/child, or any combination of, of the parent yes

_x000D_
_x000D_
    .showme{ _x000D_
        display: none;_x000D_
    }_x000D_
    .showhim:hover .showme{_x000D_
        display : block;_x000D_
    }_x000D_
    .showhim:hover .hideme{_x000D_
        display : none;_x000D_
    }_x000D_
    .showhim:hover ~ .hideme2{ _x000D_
        display:none;_x000D_
    }
_x000D_
    <div class="showhim">_x000D_
        HOVER ME_x000D_
        <div class="showme">hai</div> _x000D_
        <div class="hideme">bye</div>_x000D_
    </div>_x000D_
    <div class="hideme2">bye bye</div>
_x000D_
_x000D_
_x000D_

Execution failed for task ':app:compileDebugJavaWithJavac' Android Studio 3.1 Update

I found the solution as Its problem with Android Studio 3.1 Canary 6

My backup of Android Studio 3.1 Canary 5 is useful to me and saved my half day.

Now My build.gradle:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 27
    buildToolsVersion '27.0.2'
    defaultConfig {
        applicationId "com.example.demo"
        minSdkVersion 15
        targetSdkVersion 27
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        vectorDrawables.useSupportLibrary = true
    }
    dataBinding {
        enabled true
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    productFlavors {
    }
}

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation "com.android.support:appcompat-v7:${rootProject.ext.supportLibVersion}"
    implementation "com.android.support:design:${rootProject.ext.supportLibVersion}"
    implementation "com.android.support:support-v4:${rootProject.ext.supportLibVersion}"
    implementation "com.android.support:recyclerview-v7:${rootProject.ext.supportLibVersion}"
    implementation "com.android.support:cardview-v7:${rootProject.ext.supportLibVersion}"
    implementation "com.squareup.retrofit2:retrofit:2.3.0"
    implementation "com.google.code.gson:gson:2.8.2"
    implementation "com.android.support.constraint:constraint-layout:1.0.2"
    implementation "com.squareup.retrofit2:converter-gson:2.3.0"
    implementation "com.squareup.okhttp3:logging-interceptor:3.6.0"
    implementation "com.squareup.picasso:picasso:2.5.2"
    implementation "com.dlazaro66.qrcodereaderview:qrcodereaderview:2.0.3"
    compile 'com.github.elevenetc:badgeview:v1.0.0'
    annotationProcessor 'com.github.elevenetc:badgeview:v1.0.0'
    testImplementation "junit:junit:4.12"
    androidTestImplementation("com.android.support.test.espresso:espresso-core:3.0.1", {
        exclude group: "com.android.support", module: "support-annotations"
    })
}

and My gradle is:

classpath 'com.android.tools.build:gradle:3.1.0-alpha06'

and its working finally.

I think there problem in Android Studio 3.1 Canary 6

Thank you all for your time.

Accessing JSON object keys having spaces

The way to do this is via the bracket notation.

_x000D_
_x000D_
var test = {_x000D_
    "id": "109",_x000D_
    "No. of interfaces": "4"_x000D_
}_x000D_
alert(test["No. of interfaces"]);
_x000D_
_x000D_
_x000D_

For more info read out here:

What is the maximum number of edges in a directed graph with n nodes?

Putting it another way:

A complete graph is an undirected graph where each distinct pair of vertices has an unique edge connecting them. This is intuitive in the sense that, you are basically choosing 2 vertices from a collection of n vertices.

nC2 = n!/(n-2)!*2! = n(n-1)/2

This is the maximum number of edges an undirected graph can have. Now, for directed graph, each edge converts into two directed edges. So just multiply the previous result with two. That gives you the result: n(n-1)

Visual Studio replace tab with 4 spaces?

For VS2010 and above (VS2010 needs a plugin). If you have checked/set the options of the tab size in Visual Studio but it still won't work. Then check if you have a .editorconfig file in your project! This will override the Visual Studio settings. Edit the tab-size in that file.

This can happen if you install an Angular application in your project with the Angular-Cli.

See MSDN blog

Default SQL Server Port

The default port of SQL server is 1433.

Link to add to Google calendar

I've also been successful with this URL structure:

Base URL:

https://calendar.google.com/calendar/r/eventedit?

And let's say this is my event details:

Title: Event Title
Description: Example of some description. See more at https://stackoverflow.com/questions/10488831/link-to-add-to-google-calendar
Location: 123 Some Place
Date: February 22, 2020
Start Time: 10:00am
End Time: 11:30am
Timezone: America/New York (GMT -5)

I'd convert my details into these parameters (URL encoded):

text=Event%20Title
details=Example%20of%20some%20description.%20See%20more%20at%20https%3A%2F%2Fstackoverflow.com%2Fquestions%2F10488831%2Flink-to-add-to-google-calendar
location=123%20Some%20Place%2C%20City
dates=20200222T100000/20200222T113000
ctz=America%2FNew_York

Example link:

https://calendar.google.com/calendar/r/eventedit?text=Event%20Title&details=Example%20of%20some%20description.%20See%20more%20at%20https%3A%2F%2Fstackoverflow.com%2Fquestions%2F10488831%2Flink-to-add-to-google-calendar&location=123%20Some%20Place%2C%20City&dates=20200222T100000/20200222T113000&ctz=America%2FNew_York

Please note that since I've specified a timezone with the "ctz" parameter, I used the local times for the start and end dates. Alternatively, you can use UTC dates and exclude the timezone parameter, like this:

dates=20200222T150000Z/20200222T163000Z

Example link:

https://calendar.google.com/calendar/r/eventedit?text=Event%20Title&details=Example%20of%20some%20description.%20See%20more%20at%20https%3A%2F%2Fstackoverflow.com%2Fquestions%2F10488831%2Flink-to-add-to-google-calendar&location=123%20Some%20Place%2C%20City&dates=20200222T150000Z/20200222T163000Z

Unsafe JavaScript attempt to access frame with URL

The problem is even if you create a proxy or load the content and inject it as if it's local, any scripts that that content defines will be loaded from the other domain and cause cross-domain problems.

React JS - Uncaught TypeError: this.props.data.map is not a function

It happens because the component is rendered before the async data arrived, you should control before to render.

I resolved it in this way:

render() {
    let partners = this.props && this.props.partners.length > 0 ?
        this.props.partners.map(p=>
            <li className = "partners" key={p.id}>
                <img src={p.img} alt={p.name}/> {p.name} </li>
        ) : <span></span>;

    return (
        <div>
            <ul>{partners}</ul>
        </div>
    );
}
  • Map can not resolve when the property is null/undefined, so I did a control first

this.props && this.props.partners.length > 0 ?

Python Requests throwing SSLError

If you don't bother about certificate just use verify=False.

import requests

url = "Write your url here"

returnResponse = requests.get(url, verify=False)

Why is document.body null in my javascript?

Add your code to the onload event. The accepted answer shows this correctly, however that answer as well as all the others at the time of writing also suggest putting the script tag after the closing body tag, .

This is not valid html. However it will cause your code to work, because browsers are too kind ;)

See this answer for more info Is it wrong to place the <script> tag after the </body> tag?

Downvoted other answers for this reason.

How to clear textarea on click?

The best solution what I know so far:

<textarea name="message" onblur="if (this.value == '') {this.value = 'text here';}"   onfocus="if (this.value == 'text here') {this.value = '';}">text here</textarea>

React.js create loop through Array

You can simply do conditional check before doing map like

{Array.isArray(this.props.data.participants) && this.props.data.participants.map(function(player) {
   return <li key={player.championId}>{player.summonerName}</li>
   })
}

Now a days .map can be done in two different ways but still the conditional check is required like

.map with return

{Array.isArray(this.props.data.participants) && this.props.data.participants.map(player => {
   return <li key={player.championId}>{player.summonerName}</li>
 })
}

.map without return

{Array.isArray(this.props.data.participants) && this.props.data.participants.map(player => (
   return <li key={player.championId}>{player.summonerName}</li>
 ))
}

both the above functionalities does the same

How to read all of Inputstream in Server Socket JAVA

int c;
    String raw = "";
    do {
        c = inputstream.read();
        raw+=(char)c;
    } while(inputstream.available()>0);

InputStream.available() shows the available bytes only after one byte is read, hence do .. while

How do I import a sql data file into SQL Server?

  1. Start SQL Server Management Studio
  2. Connect to your database
  3. File > Open > File and pick your file
  4. Execute it

How to open a new form from another form

For example, you have a Button named as Button1. First click on it it will open the EventHandler of that Button2 to call another Form you should write the following code to your Button.

your name example=form2.

form2 obj=new form2();

obj.show();

To close form1, write the following code:

form1.visible=false; or form1.Hide();

excel VBA run macro automatically whenever a cell is changed

In an attempt to spot a change somewhere in a particular column (here in "W", i.e. "23"), I modified Peter Alberts' answer to:

Private Sub Worksheet_Change(ByVal Target As Range)
    If Not Target.Column = 23 Then Exit Sub
    Application.EnableEvents = False             'to prevent endless loop
    On Error GoTo Finalize                       'to re-enable the events
    MsgBox "You changed a cell in column W, row " & Target.Row
    MsgBox "You changed it to: " & Target.Value
Finalize:
    Application.EnableEvents = True
End Sub

Extract substring from a string

When finding multiple occurrences of a substring matching a pattern

    String input_string = "foo/adsfasdf/adf/bar/erqwer/";
    String regex = "(foo/|bar/)"; // Matches 'foo/' and 'bar/'

    Pattern pattern = Pattern.compile(regex);
    Matcher matcher = pattern.matcher(input_string);

    while(matcher.find()) {
      String str_matched = input_string.substring(matcher.start(), matcher.end());
        // Do something with a match found
    }

Why do I have to run "composer dump-autoload" command to make migrations work in laravel?

Short answer: classmaps are static while PSR autoloading is dynamic.

If you don't want to use classmaps, use PSR autoloading instead.

Can I rollback a transaction I've already committed? (data loss)

No, you can't undo, rollback or reverse a commit.

STOP THE DATABASE!

(Note: if you deleted the data directory off the filesystem, do NOT stop the database. The following advice applies to an accidental commit of a DELETE or similar, not an rm -rf /data/directory scenario).

If this data was important, STOP YOUR DATABASE NOW and do not restart it. Use pg_ctl stop -m immediate so that no checkpoint is run on shutdown.

You cannot roll back a transaction once it has commited. You will need to restore the data from backups, or use point-in-time recovery, which must have been set up before the accident happened.

If you didn't have any PITR / WAL archiving set up and don't have backups, you're in real trouble.

Urgent mitigation

Once your database is stopped, you should make a file system level copy of the whole data directory - the folder that contains base, pg_clog, etc. Copy all of it to a new location. Do not do anything to the copy in the new location, it is your only hope of recovering your data if you do not have backups. Make another copy on some removable storage if you can, and then unplug that storage from the computer. Remember, you need absolutely every part of the data directory, including pg_xlog etc. No part is unimportant.

Exactly how to make the copy depends on which operating system you're running. Where the data dir is depends on which OS you're running and how you installed PostgreSQL.

Ways some data could've survived

If you stop your DB quickly enough you might have a hope of recovering some data from the tables. That's because PostgreSQL uses multi-version concurrency control (MVCC) to manage concurrent access to its storage. Sometimes it will write new versions of the rows you update to the table, leaving the old ones in place but marked as "deleted". After a while autovaccum comes along and marks the rows as free space, so they can be overwritten by a later INSERT or UPDATE. Thus, the old versions of the UPDATEd rows might still be lying around, present but inaccessible.

Additionally, Pg writes in two phases. First data is written to the write-ahead log (WAL). Only once it's been written to the WAL and hit disk, it's then copied to the "heap" (the main tables), possibly overwriting old data that was there. The WAL content is copied to the main heap by the bgwriter and by periodic checkpoints. By default checkpoints happen every 5 minutes. If you manage to stop the database before a checkpoint has happened and stopped it by hard-killing it, pulling the plug on the machine, or using pg_ctl in immediate mode you might've captured the data from before the checkpoint happened, so your old data is more likely to still be in the heap.

Now that you have made a complete file-system-level copy of the data dir you can start your database back up if you really need to; the data will still be gone, but you've done what you can to give yourself some hope of maybe recovering it. Given the choice I'd probably keep the DB shut down just to be safe.

Recovery

You may now need to hire an expert in PostgreSQL's innards to assist you in a data recovery attempt. Be prepared to pay a professional for their time, possibly quite a bit of time.

I posted about this on the Pg mailing list, and ?????? ?????? linked to depesz's post on pg_dirtyread, which looks like just what you want, though it doesn't recover TOASTed data so it's of limited utility. Give it a try, if you're lucky it might work.

See: pg_dirtyread on GitHub.

I've removed what I'd written in this section as it's obsoleted by that tool.

See also PostgreSQL row storage fundamentals

Prevention

See my blog entry Preventing PostgreSQL database corruption.


On a semi-related side-note, if you were using two phase commit you could ROLLBACK PREPARED for a transction that was prepared for commit but not fully commited. That's about the closest you get to rolling back an already-committed transaction, and does not apply to your situation.

How to change value of object which is inside an array using JavaScript or jQuery?

I think this way is better

const index = projects.findIndex(project => project.value==='jquery-ui');
projects[index].desc = "updated desc";

How to "scan" a website (or page) for info, and bring it into my program?

You'd probably want to look at the HTML to see if you can find strings that are unique and near your text, then you can use line/char-offsets to get to the data.

Could be awkward in Java, if there aren't any XML classes similar to the ones found in System.XML.Linq in C#.

The Eclipse executable launcher was unable to locate its companion launcher jar windows

Windows 8 follow these 3 steps:

  1. Locate eclipse file.
  2. create shortcut on desktop.
  3. Double click on the eclipse shortcut to open the application.

Command-line tool for finding out who is locking a file

enter image description here

Computer Management->Shared Folders->Open Files

How do I get the value of a registry key and ONLY the value using powershell

Following code will enumerate all values for a certain Registry key, will sort them and will return value name : value pairs separated by colon (:):

$path = 'HKLM:\SOFTWARE\Wow6432Node\Microsoft\.NETFramework';

Get-Item -Path $path | Select-Object -ExpandProperty Property | Sort | % {
    $command = [String]::Format('(Get-ItemProperty -Path "{0}" -Name "{1}")."{1}"', $path, $_);
    $value = Invoke-Expression -Command $command;
    $_ + ' : ' + $value; };

Like this:

DbgJITDebugLaunchSetting : 16

DbgManagedDebugger : "C:\Windows\system32\vsjitdebugger.exe" PID %d APPDOM %d EXTEXT "%s" EVTHDL %d

InstallRoot : C:\Windows\Microsoft.NET\Framework\

Cannot enqueue Handshake after invoking quit

If you're trying to get a lambda, I found that ending the handler with context.done() got the lambda to finish. Before adding that 1 line, It would just run and run until it timed out.

What are the Android SDK build-tools, platform-tools and tools? And which version should be used?

About the version of Android SDK Build-tools, the answer is

By default, the Android SDK uses the most recent downloaded version of the Build Tools.

Source

In Eclipse, you can choose a specific version by using the sdk.buildtools property in the project.properties file.

There seems to be no official page explaining all the build tools. Here is what the Android team says about this.

The [build] tools, such as aidl, aapt, dexdump, and dx, are typically called by the Android build tools or Android Development Tools (ADT), so you rarely need to invoke these tools directly. As a general rule, you should rely on the build tools or the ADT plugin to call them as needed.

Source

Anyway, here is a synthesis of the differences between tools, platform-tools and build-tools:

  • Android SDK Tools
    • Location: $ANDROID_HOME/tools
    • Main tools: ant scripts (to build your APKs) and ddms (for debugging)
  • Android SDK Platform-tools
    • Location: $ANDROID_HOME/platform-tools
    • Main tool: adb (to manage the state of an emulator or an Android device)
  • Android SDK Build-tools
    • Location: $ANDROID_HOME/build-tools/$VERSION/
    • Documentation
    • Main tools: aapt (to generate R.java and unaligned, unsigned APKs), dx (to convert Java bytecode to Dalvik bytecode), and zipalign (to optimize your APKs)

malloc an array of struct pointers

I agree with @maverik above, I prefer not to hide the details with a typedef. Especially when you are trying to understand what is going on. I also prefer to see everything instead of a partial code snippet. With that said, here is a malloc and free of a complex structure.

The code uses the ms visual studio leak detector so you can experiment with the potential leaks.

#include "stdafx.h"

#include <string.h>
#include "msc-lzw.h"

#define _CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h> 



// 32-bit version
int hash_fun(unsigned int key, int try_num, int max) {
    return (key + try_num) % max;  // the hash fun returns a number bounded by the number of slots.
}


// this hash table has
// key is int
// value is char buffer
struct key_value_pair {
    int key; // use this field as the key
    char *pValue;  // use this field to store a variable length string
};


struct hash_table {
    int max;
    int number_of_elements;
    struct key_value_pair **elements;  // This is an array of pointers to mystruct objects
};


int hash_insert(struct key_value_pair *data, struct hash_table *hash_table) {

    int try_num, hash;
    int max_number_of_retries = hash_table->max;


    if (hash_table->number_of_elements >= hash_table->max) {
        return 0; // FULL
    }

    for (try_num = 0; try_num < max_number_of_retries; try_num++) {

        hash = hash_fun(data->key, try_num, hash_table->max);

        if (NULL == hash_table->elements[hash]) { // an unallocated slot
            hash_table->elements[hash] = data;
            hash_table->number_of_elements++;
            return RC_OK;
        }
    }
    return RC_ERROR;
}


// returns the corresponding key value pair struct
// If a value is not found, it returns null
//
// 32-bit version
struct key_value_pair *hash_retrieve(unsigned int key, struct hash_table *hash_table) {

    unsigned int try_num, hash;
    unsigned int max_number_of_retries = hash_table->max;

    for (try_num = 0; try_num < max_number_of_retries; try_num++) {

        hash = hash_fun(key, try_num, hash_table->max);

        if (hash_table->elements[hash] == 0) {
            return NULL; // Nothing found
        }

        if (hash_table->elements[hash]->key == key) {
            return hash_table->elements[hash];
        }
    }
    return NULL;
}


// Returns the number of keys in the dictionary
// The list of keys in the dictionary is returned as a parameter.  It will need to be freed afterwards
int keys(struct hash_table *pHashTable, int **ppKeys) {

    int num_keys = 0;

    *ppKeys = (int *) malloc( pHashTable->number_of_elements * sizeof(int) );

    for (int i = 0; i < pHashTable->max; i++) {
        if (NULL != pHashTable->elements[i]) {
            (*ppKeys)[num_keys] = pHashTable->elements[i]->key;
            num_keys++;
        }
    }
    return num_keys;
}

// The dictionary will need to be freed afterwards
int allocate_the_dictionary(struct hash_table *pHashTable) {


    // Allocate the hash table slots
    pHashTable->elements = (struct key_value_pair **) malloc(pHashTable->max * sizeof(struct key_value_pair));  // allocate max number of key_value_pair entries
    for (int i = 0; i < pHashTable->max; i++) {
        pHashTable->elements[i] = NULL;
    }



    // alloc all the slots
    //struct key_value_pair *pa_slot;
    //for (int i = 0; i < pHashTable->max; i++) {
    //  // all that he could see was babylon
    //  pa_slot = (struct key_value_pair *)  malloc(sizeof(struct key_value_pair));
    //  if (NULL == pa_slot) {
    //      printf("alloc of slot failed\n");
    //      while (1);
    //  }
    //  pHashTable->elements[i] = pa_slot;
    //  pHashTable->elements[i]->key = 0;
    //}

    return RC_OK;
}


// This will make a dictionary entry where
//   o  key is an int
//   o  value is a character buffer
//
// The buffer in the key_value_pair will need to be freed afterwards
int make_dict_entry(int a_key, char * buffer, struct key_value_pair *pMyStruct) {

    // determine the len of the buffer assuming it is a string
    int len = strlen(buffer);

    // alloc the buffer to hold the string
    pMyStruct->pValue = (char *) malloc(len + 1); // add one for the null terminator byte
    if (NULL == pMyStruct->pValue) {
        printf("Failed to allocate the buffer for the dictionary string value.");
        return RC_ERROR;
    }
    strcpy(pMyStruct->pValue, buffer);
    pMyStruct->key = a_key;

    return RC_OK;
}


// Assumes the hash table has already been allocated.
int add_key_val_pair_to_dict(struct hash_table *pHashTable, int key, char *pBuff) {

    int rc;
    struct key_value_pair *pKeyValuePair;

    if (NULL == pHashTable) {
        printf("Hash table is null.\n");
        return RC_ERROR;
    }

    // Allocate the dictionary key value pair struct
    pKeyValuePair = (struct key_value_pair *) malloc(sizeof(struct key_value_pair));
    if (NULL == pKeyValuePair) {
        printf("Failed to allocate key value pair struct.\n");
        return RC_ERROR;
    }


    rc = make_dict_entry(key, pBuff, pKeyValuePair);  // a_hash_table[1221] = "abba"
    if (RC_ERROR == rc) {
        printf("Failed to add buff to key value pair struct.\n");
        return RC_ERROR;
    }


    rc = hash_insert(pKeyValuePair, pHashTable);
    if (RC_ERROR == rc) {
        printf("insert has failed!\n");
        return RC_ERROR;
    }

    return RC_OK;
}


void dump_hash_table(struct hash_table *pHashTable) {

    // Iterate the dictionary by keys
    char * pValue;
    struct key_value_pair *pMyStruct;
    int *pKeyList;
    int num_keys;

    printf("i\tKey\tValue\n");
    printf("-----------------------------\n");
    num_keys = keys(pHashTable, &pKeyList);
    for (int i = 0; i < num_keys; i++) {
        pMyStruct = hash_retrieve(pKeyList[i], pHashTable);
        pValue = pMyStruct->pValue;
        printf("%d\t%d\t%s\n", i, pKeyList[i], pValue);
    }

    // Free the key list
    free(pKeyList);

}

int main(int argc, char *argv[]) {

    int rc;
    int i;


    struct hash_table a_hash_table;
    a_hash_table.max = 20;   // The dictionary can hold at most 20 entries.
    a_hash_table.number_of_elements = 0;  // The intial dictionary has 0 entries.
    allocate_the_dictionary(&a_hash_table);

    rc = add_key_val_pair_to_dict(&a_hash_table, 1221, "abba");
    if (RC_ERROR == rc) {
        printf("insert has failed!\n");
        return RC_ERROR;
    }
    rc = add_key_val_pair_to_dict(&a_hash_table, 2211, "bbaa");
    if (RC_ERROR == rc) {
        printf("insert has failed!\n");
        return RC_ERROR;
    }
    rc = add_key_val_pair_to_dict(&a_hash_table, 1122, "aabb");
    if (RC_ERROR == rc) {
        printf("insert has failed!\n");
        return RC_ERROR;
    }
    rc = add_key_val_pair_to_dict(&a_hash_table, 2112, "baab");
    if (RC_ERROR == rc) {
        printf("insert has failed!\n");
        return RC_ERROR;
    }
    rc = add_key_val_pair_to_dict(&a_hash_table, 1212, "abab");
    if (RC_ERROR == rc) {
        printf("insert has failed!\n");
        return RC_ERROR;
    }
    rc = add_key_val_pair_to_dict(&a_hash_table, 2121, "baba");
    if (RC_ERROR == rc) {
        printf("insert has failed!\n");
        return RC_ERROR;
    }



    // Iterate the dictionary by keys
    dump_hash_table(&a_hash_table);

    // Free the individual slots
    for (i = 0; i < a_hash_table.max; i++) {
        // all that he could see was babylon
        if (NULL != a_hash_table.elements[i]) {
            free(a_hash_table.elements[i]->pValue);  // free the buffer in the struct
            free(a_hash_table.elements[i]);  // free the key_value_pair entry
            a_hash_table.elements[i] = NULL;
        }
    }


    // Free the overall dictionary
    free(a_hash_table.elements);


    _CrtDumpMemoryLeaks();
    return 0;
}

Resolving LNK4098: defaultlib 'MSVCRT' conflicts with

I get this every time I want to create an application in VC++.

Right-click the project, select Properties then under 'Configuration properties | C/C++ | Code Generation', select "Multi-threaded Debug (/MTd)" for Debug configuration.

Note that this does not change the setting for your Release configuration - you'll need to go to the same location and select "Multi-threaded (/MT)" for Release.

Set port for php artisan.php serve

you can also add host as well with same command like :

php artisan serve --host=172.10.29.100 --port=8080

Is there a null-coalescing (Elvis) operator or safe navigation operator in javascript?

I read this article (https://www.beyondjava.net/elvis-operator-aka-safe-navigation-javascript-typescript) and modified the solution using Proxies.

function safe(obj) {
    return new Proxy(obj, {
        get: function(target, name) {
            const result = target[name];
            if (!!result) {
                return (result instanceof Object)? safe(result) : result;
            }
            return safe.nullObj;
        },
    });
}

safe.nullObj = safe({});
safe.safeGet= function(obj, expression) {
    let safeObj = safe(obj);
    let safeResult = expression(safeObj);

    if (safeResult === safe.nullObj) {
        return undefined;
    }
    return safeResult;
}

You call it like this:

safe.safeGet(example, (x) => x.foo.woo)

The result will be undefined for an expression that encounters null or undefined along its path. You could go wild and modify the Object prototype!

Object.prototype.getSafe = function (expression) {
    return safe.safeGet(this, expression);
};

example.getSafe((x) => x.foo.woo);

How can I copy data from one column to another in the same table?

How about this

UPDATE table SET columnB = columnA;

This will update every row.

How to make my font bold using css?

You can use the CSS declaration font-weight: bold;.

I would advise you to read the CSS beginner guide at http://htmldog.com/guides/cssbeginner/ .

find_spec_for_exe': can't find gem bundler (>= 0.a) (Gem::GemNotFoundException)

My problem was I'm using RVM and had the wrong Ruby version activated...

Hope this helps at least one person

Split list into smaller lists (split in half)

This is similar to other solutions, but a little faster.

# Usage: split_half([1,2,3,4,5]) Result: ([1, 2], [3, 4, 5])

def split_half(a):
    half = len(a) >> 1
    return a[:half], a[half:]

Identify if a string is a number

I guess this answer will just be lost in between all the other ones, but anyway, here goes.

I ended up on this question via Google because I wanted to check if a string was numeric so that I could just use double.Parse("123") instead of the TryParse() method.

Why? Because it's annoying to have to declare an out variable and check the result of TryParse() before you know if the parse failed or not. I want to use the ternary operator to check if the string is numerical and then just parse it in the first ternary expression or provide a default value in the second ternary expression.

Like this:

var doubleValue = IsNumeric(numberAsString) ? double.Parse(numberAsString) : 0;

It's just a lot cleaner than:

var doubleValue = 0;
if (double.TryParse(numberAsString, out doubleValue)) {
    //whatever you want to do with doubleValue
}

I made a couple extension methods for these cases:


Extension method one

public static bool IsParseableAs<TInput>(this string value) {
    var type = typeof(TInput);

    var tryParseMethod = type.GetMethod("TryParse", BindingFlags.Static | BindingFlags.Public, Type.DefaultBinder,
        new[] { typeof(string), type.MakeByRefType() }, null);
    if (tryParseMethod == null) return false;

    var arguments = new[] { value, Activator.CreateInstance(type) };
    return (bool) tryParseMethod.Invoke(null, arguments);
}

Example:

"123".IsParseableAs<double>() ? double.Parse(sNumber) : 0;

Because IsParseableAs() tries to parse the string as the appropriate type instead of just checking if the string is "numeric" it should be pretty safe. And you can even use it for non numeric types that have a TryParse() method, like DateTime.

The method uses reflection and you end up calling the TryParse() method twice which, of course, isn't as efficient, but not everything has to be fully optimized, sometimes convenience is just more important.

This method can also be used to easily parse a list of numeric strings into a list of double or some other type with a default value without having to catch any exceptions:

var sNumbers = new[] {"10", "20", "30"};
var dValues = sNumbers.Select(s => s.IsParseableAs<double>() ? double.Parse(s) : 0);

Extension method two

public static TOutput ParseAs<TOutput>(this string value, TOutput defaultValue) {
    var type = typeof(TOutput);

    var tryParseMethod = type.GetMethod("TryParse", BindingFlags.Static | BindingFlags.Public, Type.DefaultBinder,
        new[] { typeof(string), type.MakeByRefType() }, null);
    if (tryParseMethod == null) return defaultValue;

    var arguments = new object[] { value, null };
    return ((bool) tryParseMethod.Invoke(null, arguments)) ? (TOutput) arguments[1] : defaultValue;
}

This extension method lets you parse a string as any type that has a TryParse() method and it also lets you specify a default value to return if the conversion fails.

This is better than using the ternary operator with the extension method above as it only does the conversion once. It still uses reflection though...

Examples:

"123".ParseAs<int>(10);
"abc".ParseAs<int>(25);
"123,78".ParseAs<double>(10);
"abc".ParseAs<double>(107.4);
"2014-10-28".ParseAs<DateTime>(DateTime.MinValue);
"monday".ParseAs<DateTime>(DateTime.MinValue);

Outputs:

123
25
123,78
107,4
28.10.2014 00:00:00
01.01.0001 00:00:00

How do I install Java on Mac OSX allowing version switching?

Manually switching system-default version without 3rd party tools:

As detailed in this older answer, on macOS /usr/bin/java is a wrapper tool that will use Java version pointed by JAVA_HOME or if that variable is not set will look for Java installations under /Library/Java/JavaVirtualMachines/ and will use the one with highest version. It determines versions by looking at Contents/Info.plist under each package.

Armed with this knowledge you can:

  • control which version the system will use by renaming Info.plist in versions you don't want to use as default (that file is not used by the actual Java runtime itself).
  • control which version to use for specific tasks by setting $JAVA_HOME

I've just verified this is still true with OpenJDK & Mojave.

On a brand new system, there is no Java version installed:

$ java -version
No Java runtime present, requesting install.

Cancel this, download OpenJDK 11 & 12ea on https://jdk.java.net ; install OpenJDK11:

$ cd /Library/Java/JavaVirtualMachines/
$ sudo tar xzf ~/Downloads/openjdk-11.0.1_osx-x64_bin.tar.gz

System java is now 11:

$ java -version
openjdk version "11.0.1" 2018-10-16
[...]

Install OpenJDK12 (early access at the moment):

$ sudo tar xzf ~/Downloads/openjdk-12-ea+17_osx-x64_bin.tar.gz 

System java is now 12:

$ java -version
openjdk version "12-ea" 2019-03-19
[...]

Now let's "hide" OpenJDK 12 from system java wrapper:

$ cd jdk-12.jdk/Contents/
$ sudo mv Info.plist Info.plist.disabled

System java is back to 11:

$ java -version
openjdk version "11.0.1" 2018-10-16
[...]

And you can still use version 12 punctually by manually setting JAVA_HOME:

$ export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk-12.jdk/Contents/Home
$ java -version
openjdk version "12-ea" 2019-03-19
[...]

XML Error: There are multiple root elements

You can do it without modifying the XML stream: Tell the XmlReader to not be so picky. Setting the XmlReaderSettings.ConformanceLevel to ConformanceLevel.Fragment will let the parser ignore the fact that there is no root node.

        XmlReaderSettings settings = new XmlReaderSettings();
        settings.ConformanceLevel = ConformanceLevel.Fragment;
        using (XmlReader reader = XmlReader.Create(tr,settings))
        {
             ...
        }

Now you can parse something like this (which is an real time XML stream, where it is impossible to wrap with a node).

<event>
  <timeStamp>1354902435238</timeStamp>
  <eventId>7073822</eventId>
</event>
<data>
  <time>1354902435341</time>
  <payload type='80'>7d1300786a0000000bf9458b0518000000000000000000000000000000000c0c030306001b</payload>
</data>
<data>
  <time>1354902435345</time>
  <payload type='80'>fd1260780912ff3028fea5ffc0387d640fa550f40fbdf7afffe001fff8200fff00f0bf0e000042201421100224ff40312300111400004f000000e0c0fbd1e0000f10e0fccc2ff0000f0fe00f00f0eed00f11e10d010021420401</payload>
</data>
<data>
  <time>1354902435347</time>
  <payload type='80'>fd126078ad11fc4015fefdf5b042ff1010223500000000000000003007ff00f20e0f01000e0000dc0f01000f000000000000004f000000f104ff001000210f000013010000c6da000000680ffa807800200000000d00c0f0</payload>
</data>

Creating threads - Task.Factory.StartNew vs new Thread()

There is a big difference. Tasks are scheduled on the ThreadPool and could even be executed synchronous if appropiate.

If you have a long running background work you should specify this by using the correct Task Option.

You should prefer Task Parallel Library over explicit thread handling, as it is more optimized. Also you have more features like Continuation.

Form inside a form, is that alright?

No. HTML explicitly forbids nested forms.

From the HTML 5 draft:

Content model: Flow content, but with no form element descendants.

From the HTML 4.01 Recommendation:

<!ELEMENT FORM - - (%block;|SCRIPT)+ -(FORM) -- interactive form -->

(Note the -(FORM) section).

SOAP-UI - How to pass xml inside parameter

To send CDATA in a request object use the SoapObject.setInnerText("..."); method.

What is the difference between functional and non-functional requirements?

A functional requirement describes what a software system should do, while non-functional requirements place constraints on how the system will do so.

Let me elaborate.

An example of a functional requirement would be:

  • A system must send an email whenever a certain condition is met (e.g. an order is placed, a customer signs up, etc).

A related non-functional requirement for the system may be:

  • Emails should be sent with a latency of no greater than 12 hours from such an activity.

The functional requirement is describing the behavior of the system as it relates to the system's functionality. The non-functional requirement elaborates a performance characteristic of the system.

Typically non-functional requirements fall into areas such as:

  • Accessibility
  • Capacity, current and forecast
  • Compliance
  • Documentation
  • Disaster recovery
  • Efficiency
  • Effectiveness
  • Extensibility
  • Fault tolerance
  • Interoperability
  • Maintainability
  • Privacy
  • Portability
  • Quality
  • Reliability
  • Resilience
  • Response time
  • Robustness
  • Scalability
  • Security
  • Stability
  • Supportability
  • Testability

A more complete list is available at Wikipedia's entry for non-functional requirements.

Non-functional requirements are sometimes defined in terms of metrics (i.e. something that can be measured about the system) to make them more tangible. Non-functional requirements may also describe aspects of the system that don't relate to its execution, but rather to its evolution over time (e.g. maintainability, extensibility, documentation, etc.).

C++ display stack trace on exception

The following code stops the execution right after an exception is thrown. You need to set a windows_exception_handler along with a termination handler. I tested this in MinGW 32bits.

void beforeCrash(void);

static const bool SET_TERMINATE = std::set_terminate(beforeCrash);

void beforeCrash() {
    __asm("int3");
}

int main(int argc, char *argv[])
{
SetUnhandledExceptionFilter(windows_exception_handler);
...
}

Check the following code for the windows_exception_handler function: http://www.codedisqus.com/0ziVPgVPUk/exception-handling-and-stacktrace-under-windows-mingwgcc.html

SQL Error: 0, SQLState: 08S01 Communications link failure

I'm answering on specific to this error code(08s01).

usually, MySql close socket connections are some interval of time that is wait_timeout defined on MySQL server-side which by default is 8hours. so if a connection will timeout after this time and the socket will throw an exception which SQLState is "08s01".

1.use connection pool to execute Query, make sure the pool class has a function to make an inspection of the connection members before it goes time_out.

2.give a value of <wait_timeout> greater than the default, but the largest value is 24 days

3.use another parameter in your connection URL, but this method is not recommended, and maybe deprecated.

How to obtain values of request variables using Python and Flask

You can get posted form data from request.form and query string data from request.args.

myvar =  request.form["myvar"]
myvar = request.args["myvar"]

Chrome dev tools fails to show response even the content returned has header Content-Type:text/html; charset=UTF-8

For me, the issue happens when the returned JSON file is too large.

If you just want to see the response, you can get it with the help of Postman. See the steps below:

  1. Copy the request with all information(including URL, header, token, etc) from chrome debugger through Chrome Developer Tools->Network Tab->find the request->right click on it->Copy->Copy as cURL.
  2. Open postman, import->Rawtext, paste the content. Postman will recreate the same request. Then run the request you should see the JSON response. [Import cURL in postmain][1]: https://i.stack.imgur.com/dL9Qo.png

If you want to reduce the size of the API response, maybe you can return fewer fields in the response. For mongoose, you can easily do this by providing a field name list when calling the find() method. For exmaple, convert the method from:

const users = await User.find().lean();

To:

const users = await User.find({}, '_id username email role timecreated').lean();

In my case, there is field called description, which is a large string. After removing it from the field list, the response size is reduced from 6.6 MB to 404 KB.

OraOLEDB.Oracle provider is not registered on the local machine

I had the same issue but my solution was to keep the Platform target as Any CPU and UNCHECK Prefer 32-bit checkbox. After I unchecked it I was able to open a connection with the provider.

Turn Prefer 32-bit off

os.walk without digging into directories below

You could use os.listdir() which returns a list of names (for both files and directories) in a given directory. If you need to distinguish between files and directories, call os.stat() on each name.

Daemon not running. Starting it now on port 5037

This worked for me: Open task manager (of your OS) and kill adb.exe process. Now start adb again, now adb should start normally.

Is it possible to use raw SQL within a Spring Repository

we can use createNativeQuery("Here Nagitive SQL Query ");

for Example :

Query q = em.createNativeQuery("SELECT a.firstname, a.lastname FROM Author a");
List<Object[]> authors = q.getResultList();

Convert a tensor to numpy array in Tensorflow?

Maybe you can try,this method:

import tensorflow as tf
W1 = tf.Variable(tf.random_uniform([1], -1.0, 1.0))
init = tf.global_variables_initializer()
sess = tf.Session()
sess.run(init)
array = W1.eval(sess)
print (array)

Where is SQL Server Management Studio 2012?

On the Official SQL Server 2012 ISO that's for download, just navigate to \x64\Setup\ (or \x86\Setup) and you will find "sql_ssms.msi". It's only about 60 MB, and since it's an .MSI you can probably provision it to be installed automatically (say for a large lab or classroom environment).

How to process SIGTERM signal gracefully?

The simplest solution I have found, taking inspiration by responses above is

class SignalHandler:

    def __init__(self):

        # register signal handlers
        signal.signal(signal.SIGINT, self.exit_gracefully)
        signal.signal(signal.SIGTERM, self.exit_gracefully)

        self.logger = Logger(level=ERROR)

    def exit_gracefully(self, signum, frame):
        self.logger.info('captured signal %d' % signum)
        traceback.print_stack(frame)

        ###### do your resources clean up here! ####

        raise(SystemExit)

How to use code to open a modal in Angular 2?

The Way i used to do it without lots of coding is.. I have the hidden button with the id="employeeRegistered"

On my .ts file I import ElementRef from '@angular/core'

Then after I process everything on my (click) method do as follow:

this.el.nativeElement.querySelector('#employeeRegistered').click();

then the modal displays as expected..

How can I export Excel files using JavaScript?

Create an AJAX postback method which writes a CSV file to your webserver and returns the url.. Set a hidden IFrame in the browser to the location of the CSV file on the server.

Your user will then be presented with the CSV download link.

How to get random value out of an array?

I'm basing my answer off of @ÓlafurWaage's function. I tried to use it but was running into reference issues when I had tried to modify the return object. I updated his function to pass and return by reference. The new function is:

function &random_value(&$array, $default=null)
{
    $k = mt_rand(0, count($array) - 1);
    if (isset($array[$k])) {
        return $array[$k];
    } else {
        return $default;
    }
}

For more context, see my question over at Passing/Returning references to object + changing object is not working

Python: Get the first character of the first string in a list?

Get the first character of a bare python string:

>>> mystring = "hello"
>>> print(mystring[0])
h
>>> print(mystring[:1])
h
>>> print(mystring[3])
l
>>> print(mystring[-1])
o
>>> print(mystring[2:3])
l
>>> print(mystring[2:4])
ll

Get the first character from a string in the first position of a python list:

>>> myarray = []
>>> myarray.append("blah")
>>> myarray[0][:1]
'b'
>>> myarray[0][-1]
'h'
>>> myarray[0][1:3]
'la'

Many people get tripped up here because they are mixing up operators of Python list objects and operators of Numpy ndarray objects:

Numpy operations are very different than python list operations.

Wrap your head around the two conflicting worlds of Python's "list slicing, indexing, subsetting" and then Numpy's "masking, slicing, subsetting, indexing, then numpy's enhanced fancy indexing".

These two videos cleared things up for me:

"Losing your Loops, Fast Numerical Computing with NumPy" by PyCon 2015: https://youtu.be/EEUXKG97YRw?t=22m22s

"NumPy Beginner | SciPy 2016 Tutorial" by Alexandre Chabot LeClerc: https://youtu.be/gtejJ3RCddE?t=1h24m54s

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 to change to an older version of Node.js

Another good library for managing multiple versions of Node is N: https://github.com/visionmedia/n

How to fill the whole canvas with specific color?

You know what, there is an entire library for canvas graphics. It is called p5.js You can add it with just a single line in your head element and an additional sketch.js file.

Do this to your html and body tags first:

<html style="margin:0 ; padding:0">
<body style="margin:0 ; padding:0">

Add this to your head:

<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.6.1/p5.js"></script>
<script type="text/javascript" src="sketch.js"></script>

The sketch.js file

function setup() {
    createCanvas(windowWidth, windowHeight);
    background(r, g, b);
}

How to view the committed files you have not pushed yet?

Here you'll find your answer:

Using Git how do I find changes between local and remote

For the lazy:

  1. Use "git log origin..HEAD"
  2. Use "git fetch" followed by "git log HEAD..origin". You can cherry-pick individual commits using the listed commit ids.

The above assumes, of course, that "origin" is the name of your remote tracking branch (which it is if you've used clone with default options).

Python - How to concatenate to a string in a for loop?

This should work:

endstring = ''.join(list)

Bind service to activity in Android

I tried to call

startService(oIntent);
bindService(oIntent, mConnection, Context.BIND_AUTO_CREATE);

consequently and I could create a sticky service and bind to it. Detailed tutorial for Bound Service Example.

How to explain callbacks in plain english? How are they different from calling one function from another function?

Always better to start with an example :).

Let's assume you have two modules A and B.

You want module A to be notified when some event/condition occurs in module B. However, module B has no idea about your module A. All it knows is an address to a particular function (of module A) through a function pointer that is provided to it by module A.

So all B has to do now, is "callback" into module A when a particular event/condition occurs by using the function pointer. A can do further processing inside the callback function.

*) A clear advantage here is that you are abstracting out everything about module A from module B. Module B does not have to care who/what module A is.

How to add jQuery in JS file

If you frequently want to update your jquery file link to a new version file, across your site on many pages, at one go..

Create a javascript file (.js) and put in the below code, and map this javascript file to all the pages (instead of mapping jquery file directly on the page), so when the jquery file link is updated on this javascript file it will reflect across the site.

The below code is tested and it works good!

document.write('<');
document.write('script ');
document.write('src="');
//next line is the path to jquery file
document.write('/javascripts/jquery-1.4.1.js');
document.write('" type="text/javascript"></');
document.write('script');
document.write('>');

Android custom Row Item for ListView

Step 1:Create a XML File

 <?xml version="1.0" encoding="utf-8"?>
    <LinearLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">


        <ListView
            android:id="@+id/lvItems"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            />
    </LinearLayout>

Step 2:Studnet.java

package com.scancode.acutesoft.telephonymanagerapp;


public class Student
{
    String email,phone,address;

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

Step 3:MainActivity.java

 package com.scancode.acutesoft.telephonymanagerapp;

    import android.app.Activity;
    import android.os.Bundle;
    import android.widget.ListView;

    import java.util.ArrayList;

    public class MainActivity extends Activity  {

        ListView lvItems;
        ArrayList<Student> studentArrayList ;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            lvItems = (ListView) findViewById(R.id.lvItems);
            studentArrayList = new ArrayList<Student>();
            dataSaving();
            CustomAdapter adapter = new CustomAdapter(MainActivity.this,studentArrayList);
            lvItems.setAdapter(adapter);
        }

        private void dataSaving() {

            Student student = new Student();
            student.setEmail("[email protected]");
            student.setPhone("1234567890");
            student.setAddress("Hyderabad");
            studentArrayList.add(student);


            student = new Student();
            student.setEmail("[email protected]");
            student.setPhone("1234567890");
            student.setAddress("Banglore");
            studentArrayList.add(student);

            student = new Student();
            student.setEmail("[email protected]");
            student.setPhone("1234567890");
            student.setAddress("Banglore");
            studentArrayList.add(student);

            student = new Student();
            student.setEmail("[email protected]");
            student.setPhone("1234567890");
            student.setAddress("Banglore");
            studentArrayList.add(student);
        }


    }

Step 4:CustomAdapter.java

  package com.scancode.acutesoft.telephonymanagerapp;

    import android.content.Context;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.BaseAdapter;
    import android.widget.TextView;

    import java.util.ArrayList;


    public class CustomAdapter extends BaseAdapter
    {
        ArrayList<Student> studentList;
        Context mContext;


        public CustomAdapter(Context context, ArrayList<Student> studentArrayList) {
            this.mContext = context;
            this.studentList = studentArrayList;

        }

        @Override
        public int getCount() {
            return studentList.size();
        }
        @Override
        public Object getItem(int position) {
            return position;
        }

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {

            Student student = studentList.get(position);
            convertView = LayoutInflater.from(mContext).inflate(R.layout.student_row,null);

            TextView tvStudEmail = (TextView) convertView.findViewById(R.id.tvStudEmail);
            TextView tvStudPhone = (TextView) convertView.findViewById(R.id.tvStudPhone);
            TextView tvStudAddress = (TextView) convertView.findViewById(R.id.tvStudAddress);

            tvStudEmail.setText(student.getEmail());
            tvStudPhone.setText(student.getPhone());
            tvStudAddress.setText(student.getAddress());


            return convertView;
        }
    }

Activity has leaked window that was originally added

Best solution is just add dialog in try catch and dismiss dialog when exception occur

Just use below code

 try {
        dialog.show();
    } catch (Exception e) {
        dialog.dismiss();
    }

Number input type that takes only integers?

In the Future™ (see Can I Use), on user agents that present a keyboard to you, you can restrict a text input to just numeric with input[inputmode].

How can I set a website image that will show as preview on Facebook?

If you're using Weebly, start by viewing the published site and right-clicking the image to Copy Image Address. Then in Weebly, go to Edit Site, Pages, click the page you wish to use, SEO Settings, under Header Code enter the code from Shef's answer:

<meta property="og:image" content="/uploads/..." />

just replacing /uploads/... with the copied image address. Click Publish to apply the change.

You can skip the part of Shef's answer about namespace, because that's already set by default in Weebly.

Delete default value of an input text on click

This is somewhat cleaner, i think. Note the usage of the "defaultValue" property of the input:

<script>
function onBlur(el) {
    if (el.value == '') {
        el.value = el.defaultValue;
    }
}
function onFocus(el) {
    if (el.value == el.defaultValue) {
        el.value = '';
    }
}
</script>
<form>
<input type="text" value="[some default value]" onblur="onBlur(this)" onfocus="onFocus(this)" />
</form>

What is /dev/null 2>&1?

>> /dev/null redirects standard output (stdout) to /dev/null, which discards it.

(The >> seems sort of superfluous, since >> means append while > means truncate and write, and either appending to or writing to /dev/null has the same net effect. I usually just use > for that reason.)

2>&1 redirects standard error (2) to standard output (1), which then discards it as well since standard output has already been redirected.

WordPress Get the Page ID outside the loop

Use below two lines of code to get current page or post ID

global $post;
echo $post->ID;

SSIS Connection Manager Not Storing SQL Password

There is easy way of doing this. I don't know why people are giving complicated answers.

Double click SSIS package. Then go to connection manager, select DestinationConnectionOLDB and then add password next to login field.

Example: Data Source=SysproDB1;User ID=test;password=test;Initial Catalog=ASBuiltDW;Provider=SQLNCLI11;Auto Translate=false;

Do same for SourceConnectionOLDB.

How can I clear an HTML file input with JavaScript?

Here are my two cents, the input files are stored as array so here is how to null it

document.getElementById('selector').value = []

this return an empty array and works on all browsers

Performance of Java matrix math libraries?

Linalg code that relies heavily on Pentiums and later processors' vector computing capabilities (starting with the MMX extensions, like LAPACK and now Atlas BLAS) is not "fantastically optimized", but simply industry-standard. To replicate that perfomance in Java you are going to need native libraries. I have had the same performance problem as you describe (mainly, to be able to compute Choleski decompositions) and have found nothing really efficient: Jama is pure Java, since it is supposed to be just a template and reference kit for implementers to follow... which never happened. You know Apache math commons... As for COLT, I have still to test it but it seems to rely heavily on Ninja improvements, most of which were reached by building an ad-hoc Java compiler, so I doubt it's going to help. At that point, I think we "just" need a collective effort to build a native Jama implementation...

Generate UML Class Diagram from Java Project

I wrote Class Visualizer, which does it. It's free tool which has all the mentioned functionality - I personally use it for the same purposes, as described in this post. For each browsed class it shows 2 instantly generated class diagrams: class relations and class UML view. Class relations diagram allows to traverse through the whole structure. It has full support for annotations and generics plus special support for JPA entities. Works very well with big projects (thousands of classes).

TabLayout tab selection

A bit late but might be a useful solution. I am using my TabLayout directly in my Fragment and trying to select a tab quite early in the Fragment's Lifecycle. What worked for me was to wait until the TabLayout finished drawing its child views by using android.view.View#post method. i.e:

int myPosition = 0;
myFilterTabLayout.post(() -> { filterTabLayout.getTabAt(myPosition).select(); });

Display QImage with QtGui

As far as I know, QPixmap is used for displaying images and QImage for reading them. There are QPixmap::convertFromImage() and QPixmap::fromImage() functions to convert from QImage.

How to sort a List<Object> alphabetically using Object name field

Using Java 8 Comparator.comparing:

list.sort(Comparator.comparing(Campaign::getName));

drag drop files into standard html file input

Few years later, I've built this library to do drop files into any HTML element.

You can use it like

const Droppable = require('droppable');

const droppable = new Droppable({
    element: document.querySelector('#my-droppable-element')
})

droppable.onFilesDropped((files) => {
    console.log('Files were dropped:', files);
});

// Clean up when you're done!
droppable.destroy();

Accessing JPEG EXIF rotation data in JavaScript on the client side

I upload expansion code to show photo by android camera on html as normal on some img tag with right rotaion, especially for img tag whose width is wider than height. I know this code is ugly but you don't need to install any other packages. (I used above code to obtain exif rotation value, Thank you.)

function getOrientation(file, callback) {
  var reader = new FileReader();
  reader.onload = function(e) {

    var view = new DataView(e.target.result);
    if (view.getUint16(0, false) != 0xFFD8) return callback(-2);
    var length = view.byteLength, offset = 2;
    while (offset < length) {
      var marker = view.getUint16(offset, false);
      offset += 2;
      if (marker == 0xFFE1) {
        if (view.getUint32(offset += 2, false) != 0x45786966) return callback(-1);
        var little = view.getUint16(offset += 6, false) == 0x4949;
        offset += view.getUint32(offset + 4, little);
        var tags = view.getUint16(offset, little);
        offset += 2;
        for (var i = 0; i < tags; i++)
          if (view.getUint16(offset + (i * 12), little) == 0x0112)
            return callback(view.getUint16(offset + (i * 12) + 8, little));
      }
      else if ((marker & 0xFF00) != 0xFF00) break;
      else offset += view.getUint16(offset, false);
    }
    return callback(-1);
  };
  reader.readAsArrayBuffer(file);
}

var isChanged = false;
function rotate(elem, orientation) {
    if (isIPhone()) return;

    var degree = 0;
    switch (orientation) {
        case 1:
            degree = 0;
            break;
        case 2:
            degree = 0;
            break;
        case 3:
            degree = 180;
            break;
        case 4:
            degree = 180;
            break;
        case 5:
            degree = 90;
            break;
        case 6:
            degree = 90;
            break;
        case 7:
            degree = 270;
            break;
        case 8:
            degree = 270;
            break;
    }
    $(elem).css('transform', 'rotate('+ degree +'deg)')
    if(degree == 90 || degree == 270) {
        if (!isChanged) {
            changeWidthAndHeight(elem)
            isChanged = true
        }
    } else if ($(elem).css('height') > $(elem).css('width')) {
        if (!isChanged) {
            changeWidthAndHeightWithOutMargin(elem)
            isChanged = true
        } else if(degree == 180 || degree == 0) {
            changeWidthAndHeightWithOutMargin(elem)
            if (!isChanged)
                isChanged = true
            else
                isChanged = false
        }
    }
}


function changeWidthAndHeight(elem){
    var e = $(elem)
    var width = e.css('width')
    var height = e.css('height')
    e.css('width', height)
    e.css('height', width)
    e.css('margin-top', ((getPxInt(height) - getPxInt(width))/2).toString() + 'px')
    e.css('margin-left', ((getPxInt(width) - getPxInt(height))/2).toString() + 'px')
}

function changeWidthAndHeightWithOutMargin(elem){
    var e = $(elem)
    var width = e.css('width')
    var height = e.css('height')
    e.css('width', height)
    e.css('height', width)
    e.css('margin-top', '0')
    e.css('margin-left', '0')
}

function getPxInt(pxValue) {
    return parseInt(pxValue.trim("px"))
}

function isIPhone(){
    return (
        (navigator.platform.indexOf("iPhone") != -1) ||
        (navigator.platform.indexOf("iPod") != -1)
    );
}

and then use such as

$("#banner-img").change(function () {
    var reader = new FileReader();
    getOrientation(this.files[0], function(orientation) {
        rotate($('#banner-img-preview'), orientation, 1)
    });

    reader.onload = function (e) {
        $('#banner-img-preview').attr('src', e.target.result)
        $('#banner-img-preview').css('display', 'inherit')

    };

    // read the image file as a data URL.
    reader.readAsDataURL(this.files[0]);

});

Email address validation in C# MVC 4 application: with or without using Regex

Why not just use the EmailAttribute?

[Email(ErrorMessage = "Bad email")]
public string Email { get; set; }

Removing All Items From A ComboBox?

In Access 2013 I've just tested this:

While ComboBox1.ListCount > 0
    ComboBox1.RemoveItem 0
Wend

Interestingly, if you set the item list in Properties, this is not lost when you exit Form View and go back to Design View.

Last Key in Python Dictionary

It doesn't make sense to ask for the "last" key in a dictionary, because dictionary keys are unordered. You can get the list of keys and get the last one if you like, but that's not in any sense the "last key in a dictionary".

Double % formatting question for printf in Java

Following is the list of conversion characters that you may use in the printf:

%d – for signed decimal integer

%f – for the floating point

%o – octal number

%c – for a character

%s – a string

%i – use for integer base 10

%u – for unsigned decimal number

%x – hexadecimal number

%% – for writing % (percentage)

%n – for new line = \n

How can I get a process handle by its name in C++?

Check out: MSDN Article

You can use GetModuleName (I think?) to get the name and check against that.

How to save an HTML5 Canvas as an image on a server?

I've worked on something similar. Had to convert canvas Base64-encoded image to Uint8Array Blob.

function b64ToUint8Array(b64Image) {
   var img = atob(b64Image.split(',')[1]);
   var img_buffer = [];
   var i = 0;
   while (i < img.length) {
      img_buffer.push(img.charCodeAt(i));
      i++;
   }
   return new Uint8Array(img_buffer);
}

var b64Image = canvas.toDataURL('image/jpeg');
var u8Image  = b64ToUint8Array(b64Image);

var formData = new FormData();
formData.append("image", new Blob([ u8Image ], {type: "image/jpg"}));

var xhr = new XMLHttpRequest();
xhr.open("POST", "/api/upload", true);
xhr.send(formData);

phpMyAdmin on MySQL 8.0

I had this problem, did not find any ini file in Windows, but the solution that worked for me was very simple.
1. Open the mysql installer.
2. Reconfigure mysql server, it is the first link.
3. Go to authentication method.
4. Choose 'Legacy authentication'.
5. Give your password(next field).
6. Apply changes.

That's it, hope my solution works fine for you as well!

How to Remove Array Element and Then Re-Index Array?

2020 Benchmark in PHP 7.4

For these who are not satisfied with current answers, I did a little benchmark script, anyone can run from CLI.

We are going to compare two solutions:

unset() with array_values() VS array_splice().

<?php

echo 'php v' . phpversion() . "\n";

$itemsOne = [];
$itemsTwo = [];

// populate items array with 100k random strings
for ($i = 0; $i < 100000; $i++) {
    $itemsOne[] = $itemsTwo[] = sha1(uniqid(true));
}

$start = microtime(true);

for ($i = 0; $i < 10000; $i++) {
    unset($itemsOne[$i]);
    $itemsOne = array_values($itemsOne);
}

$end = microtime(true);

echo 'unset & array_values: ' . ($end - $start) . 's' . "\n";

$start = microtime(true);

for ($i = 0; $i < 10000; $i++) {
    array_splice($itemsTwo, $i, 1);
}

$end = microtime(true);

echo 'array_splice: ' . ($end - $start) . 's' . "\n"; 

As you can see the idea is simple:

  • Create two arrays both with the same 100k items (randomly generated strings)
  • Remove 10k first items from first array using unset() and array_values() to reindex
  • Remove 10k first items from second array using array_splice()
  • Measure time for both methods

Output of the script above on my Dell Latitude i7-6600U 2.60GHz x 4 and 15.5GiB RAM:

php v7.4.8
unset & array_values: 29.089932918549s
array_splice: 17.94264793396s

Verdict: array_splice is almost twice more performant than unset and array_values.

So: array_splice is the winner!

Name does not exist in the current context

I also faced a similar issue, the problem was the form was inside a folder and the file .aspx.designer.cs I had the namespace referencing specifically to that directory; which caused the error to appear in several components:

El nombre no existe en el contexto actual

This in your case, a possible solution is to leave the namespace line of the Members_Jobs.aspx.designer.cs file specified globally, ie change this

namespace stman.Members {

For this

namespace stman {

It's what helped me solve the problem.

I hope to be helpful

How do I configure php to enable pdo and include mysqli on CentOS?

You might just have to install the packages.

yum install php-pdo php-mysqli

After they're installed, restart Apache.

httpd restart

or

apachectl restart

How to view the roles and permissions granted to any database user in Azure SQL server instance?

Per the MSDN documentation for sys.database_permissions, this query lists all permissions explicitly granted or denied to principals in the database you're connected to:

SELECT DISTINCT pr.principal_id, pr.name, pr.type_desc, 
    pr.authentication_type_desc, pe.state_desc, pe.permission_name
FROM sys.database_principals AS pr
JOIN sys.database_permissions AS pe
    ON pe.grantee_principal_id = pr.principal_id;

Per Managing Databases and Logins in Azure SQL Database, the loginmanager and dbmanager roles are the two server-level security roles available in Azure SQL Database. The loginmanager role has permission to create logins, and the dbmanager role has permission to create databases. You can view which users belong to these roles by using the query you have above against the master database. You can also determine the role memberships of users on each of your user databases by using the same query (minus the filter predicate) while connected to them.

Get human readable version of file size?

You should use "humanize".

>>> humanize.naturalsize(1000000)
'1.0 MB'
>>> humanize.naturalsize(1000000, binary=True)
'976.6 KiB'
>>> humanize.naturalsize(1000000, gnu=True)
'976.6K'

Reference:

https://pypi.org/project/humanize/

What is monkey patching?

According to Wikipedia:

In Python, the term monkey patch only refers to dynamic modifications of a class or module at runtime, motivated by the intent to patch existing third-party code as a workaround to a bug or feature which does not act as you desire.

Plot yerr/xerr as shaded region rather than error bars

This is basically the same answer provided by Evert, but extended to show-off some cool options of fill_between

enter image description here

from matplotlib import pyplot as pl
import numpy as np

pl.clf()
pl.hold(1)

x = np.linspace(0, 30, 100)
y = np.sin(x) * 0.5
pl.plot(x, y, '-k')


x = np.linspace(0, 30, 30)
y = np.sin(x/6*np.pi)
error = np.random.normal(0.1, 0.02, size=y.shape) +.1
y += np.random.normal(0, 0.1, size=y.shape)

pl.plot(x, y, 'k', color='#CC4F1B')
pl.fill_between(x, y-error, y+error,
    alpha=0.5, edgecolor='#CC4F1B', facecolor='#FF9848')

y = np.cos(x/6*np.pi)    
error = np.random.rand(len(y)) * 0.5
y += np.random.normal(0, 0.1, size=y.shape)
pl.plot(x, y, 'k', color='#1B2ACC')
pl.fill_between(x, y-error, y+error,
    alpha=0.2, edgecolor='#1B2ACC', facecolor='#089FFF',
    linewidth=4, linestyle='dashdot', antialiased=True)



y = np.cos(x/6*np.pi)  + np.sin(x/3*np.pi)  
error = np.random.rand(len(y)) * 0.5
y += np.random.normal(0, 0.1, size=y.shape)
pl.plot(x, y, 'k', color='#3F7F4C')
pl.fill_between(x, y-error, y+error,
    alpha=1, edgecolor='#3F7F4C', facecolor='#7EFF99',
    linewidth=0)



pl.show()

Convert DataTable to IEnumerable<T>

If you want to convert any DataTable to a equivalent IEnumerable vector function.

Please take a look at the following generic function, this may help your needs (you may need to include write cases for different datatypes based on your needs).

/// <summary>
    /// Get entities from DataTable
    /// </summary>
    /// <typeparam name="T">Type of entity</typeparam>
    /// <param name="dt">DataTable</param>
    /// <returns></returns>
    public IEnumerable<T> GetEntities<T>(DataTable dt)
    {
        if (dt == null)
        {
            return null;
        }

        List<T> returnValue = new List<T>();
        List<string> typeProperties = new List<string>();

        T typeInstance = Activator.CreateInstance<T>();

        foreach (DataColumn column in dt.Columns)
        {
            var prop = typeInstance.GetType().GetProperty(column.ColumnName, BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public);
            if (prop != null)
            {
                typeProperties.Add(column.ColumnName);
            }
        }

        foreach (DataRow row in dt.Rows)
        {
            T entity = Activator.CreateInstance<T>();

            foreach (var propertyName in typeProperties)
            {

                if (row[propertyName] != DBNull.Value)
                {
                    string str = row[propertyName].GetType().FullName;

                    if (entity.GetType().GetProperty(propertyName).PropertyType == typeof(System.String))
                    {
                        object Val = row[propertyName].ToString();
                        entity.GetType().GetProperty(propertyName, BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public).SetValue(entity, Val, BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public, null, null, null);
                    }
                    else if (entity.GetType().GetProperty(propertyName).PropertyType == typeof(System.Guid)) 
                    {
                        object Val = Guid.Parse(row[propertyName].ToString());
                        entity.GetType().GetProperty(propertyName, BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public).SetValue(entity, Val, BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public, null, null, null);
                    }
                    else
                    {
                        entity.GetType().GetProperty(propertyName, BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public).SetValue(entity, row[propertyName], BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public, null, null, null);
                    }
                }
                else
                {
                    entity.GetType().GetProperty(propertyName, BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public).SetValue(entity, null, BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Public, null, null, null);
                }
            }

            returnValue.Add(entity);
        }

        return returnValue.AsEnumerable();
    }

VideoView Full screen in android application

whether you want to keep the aspect ratio of a video or stretch it to fill its parent area, using the right layout manager can get the job done.

Keep the aspect ratio :

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

<VideoView
  android:id="@+id/videoView"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:layout_gravity="center"/>

</LinearLayout>

!!! To fill in the field:

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

    <VideoView android:id="@+id/videoViewRelative"
         android:layout_alignParentTop="true"
         android:layout_alignParentBottom="true"
         android:layout_alignParentLeft="true"
         android:layout_alignParentRight="true"
         android:layout_width="fill_parent"
         android:layout_height="fill_parent">
    </VideoView>

</RelativeLayout>

Getting unique values in Excel by using formulas only

Drew Sherman's solution is very good, but the list must be contiguous (he suggests manually sorting, and that is not acceptable for me). Guitarthrower's solution is kinda slow if the number of items is large and don't respects the order of the original list: it outputs a sorted list regardless.

I wanted the original order of the items (that were sorted by the date in another column), and additionally I wanted to exclude an item from the final list not only if it was duplicated, but also for a variety of other reasons.

My solution is an improvement on Drew Sherman's solution. Likewise, this solution uses 2 columns for intermediate calculations:

Column A:

The list with duplicates and maybe blanks that you want to filter. I will position it in the A11:A1100 interval as an example, because I had trouble moving the Drew Sherman's solution to situations where it didn't start in the first line.

Column B:

This formula will output 0 if the value in this line is valid (contains a non-duplicated value). Note that you can add any other exclusion conditions that you want in the first IF, or as yet another outer IF.

=IF(ISBLANK(A11);1;IF(COUNTIF($A$11:A11;A11)=1;0;COUNTIF($A11:A$1100;A11)))

Use smart copy to populate the column.

Column C:

In the first line we will find the first valid line:

=MATCH(0;B11:B1100;0)

From that position, we search for the next valid value with the following formula:

=C11+MATCH(0;OFFSET($B$11:$B$1100;C11;0);0)

Put it in the second line and use smart copy to fill the rest of the column. This formula will output #N/D error when there is no more unique itens to point. We will take advantage of this in the next column.

Column D:

Now we just have to get the values pointed by column C:

=IFERROR(INDEX($A$11:$A$1100; C11); "")

Use smart copy to populate the column. This is the output unique list.

NoSuchMethodError in javax.persistence.Table.indexes()[Ljavax/persistence/Index

You probablly have 2 different versions of hibernate-jpa-api on the classpath. To check that run:

mvn dependency:tree >dep.txt

Then search if there are hibernate-jpa-2.0-api and hibernate-jpa-2.1-api. And exclude the excess one.

setTimeout / clearTimeout problems

That's because timer is a local variable to your function.

Try creating it outside of the function.

How to resolve merge conflicts in Git repository?

Simply, if you know well that changes in one of the repositories is not important, and want to resolve all changes in favor of the other one, use:

git checkout . --ours

to resolve changes in the favor of your repository, or

git checkout . --theirs

to resolve changes in favor of the other or the main repository.

Or else you will have to use a GUI merge tool to step through files one by one, say the merge tool is p4merge, or write any one's name you've already installed

git mergetool -t p4merge

and after finishing a file, you will have to save and close, so the next one will open.

ConvergenceWarning: Liblinear failed to converge, increase the number of iterations

Explicitly specifying the max_iter resolves the warning as the default max_iter is 100. [For Logistic Regression].

 logreg = LogisticRegression(max_iter=1000)