Programs & Examples On #Copy on write

What is copy-on-write?

I found this good article about zval in PHP, which mentioned COW too:

Copy On Write (abbreviated as ‘COW’) is a trick designed to save memory. It is used more generally in software engineering. It means that PHP will copy the memory (or allocate new memory region) when you write to a symbol, if this one was already pointing to a zval.

jquery append div inside div with id and manipulate

Why not go even simpler with either one of these options:

$("#box").html('<div id="myid" style="display:block; float:left;width:'+width+'px; height:'+height+'px; margin-top:'+positionY+'px;margin-left:'+positionX+'px;border:1px dashed #CCCCCC;"></div>');

Or, if you want to append it to existing content:

$("#box").append('<div id="myid" style="display:block; float:left;width:'+width+'px; height:'+height+'px; margin-top:'+positionY+'px;margin-left:'+positionX+'px;border:1px dashed #CCCCCC;"></div>');

Note: I put the id="myid" right into the HTML string rather than using separate code to set it.

Both the .html() and .append() jQuery methods can take a string of HTML so there's no need to use a separate step for creating the objects.

Handle Guzzle exception and get HTTP body

While the answers above are good they will not catch network errors. As Mark mentioned, BadResponseException is just a super class for ClientException and ServerException. But RequestException is also a super class of BadResponseException. RequestException will be thrown for not only 400 and 500 errors but network errors and infinite redirects too. So let's say you request the page below but your network is playing up and your catch is only expecting a BadResponseException. Well your application will throw an error.

It's better in this case to expect RequestException and check for a response.

try {
  $client->get('http://123123123.com')
} catch (RequestException $e) {

  // If there are network errors, we need to ensure the application doesn't crash.
  // if $e->hasResponse is not null we can attempt to get the message
  // Otherwise, we'll just pass a network unavailable message.
  if ($e->hasResponse()) {
    $exception = (string) $e->getResponse()->getBody();
    $exception = json_decode($exception);
    return new JsonResponse($exception, $e->getCode());
  } else {
    return new JsonResponse($e->getMessage(), 503);
  }

}

How to change column datatype from character to numeric in PostgreSQL 8.4

Step 1: Add new column with integer or numeric as per your requirement

Step 2: Populate data from varchar column to numeric column

Step 3: drop varchar column

Step 4: change new numeric column name as per old varchar column

MySQL said: Documentation #1045 - Access denied for user 'root'@'localhost' (using password: NO)

On OSX I had same difficult, but a figure out a solucition

open terminal

put 'cd /Applications/XAMPP/xamppfiles'
put 'sudo ./xampp security'

then put your root password and answer the questions

Scroll to the top of the page after render in react.js

None of the above answers is currently working for me. It turns out that .scrollTo is not as widely compatible as .scrollIntoView.

In our App.js, in componentWillMount() we added

    this.props.history.listen((location, action) => {
            setTimeout(() => { document.getElementById('root').scrollIntoView({ behavior: "smooth" }) }, 777)
        })

This is the only solution that is working universally for us. root is the ID of our App. The "smooth" behavior doesn't work on every browser / device. The 777 timeout is a bit conservative, but we load a lot of data on every page, so through testing this was necessary. A shorter 237 might work for most applications.

Why is JsonRequestBehavior needed?

To make it easier for yourself you could also create an actionfilterattribute

public class AllowJsonGetAttribute : ActionFilterAttribute
{
    public override void OnResultExecuting(ResultExecutingContext filterContext)
    {
        var jsonResult = filterContext.Result as JsonResult;

        if (jsonResult == null)
            throw new ArgumentException("Action does not return a JsonResult, 
                                                   attribute AllowJsonGet is not allowed");

        jsonResult.JsonRequestBehavior = JsonRequestBehavior.AllowGet;            

        base.OnResultExecuting(filterContext);
    }
}

and use it on your action

[AllowJsonGet]
public JsonResult MyAjaxAction()
{
    return Json("this is my test");
}

what is the difference between uint16_t and unsigned short int incase of 64 bit processor?

uint16_t is guaranteed to be a unsigned integer that is 16 bits large

unsigned short int is guaranteed to be a unsigned short integer, where short integer is defined by the compiler (and potentially compiler flags) you are currently using. For most compilers for x86 hardware a short integer is 16 bits large.

Also note that per the ANSI C standard only the minimum size of 16 bits is defined, the maximum size is up to the developer of the compiler

Minimum Type Limits

Any compiler conforming to the Standard must also respect the following limits with respect to the range of values any particular type may accept. Note that these are lower limits: an implementation is free to exceed any or all of these. Note also that the minimum range for a char is dependent on whether or not a char is considered to be signed or unsigned.

Type Minimum Range

signed char     -127 to +127
unsigned char      0 to 255
short int     -32767 to +32767
unsigned short int 0 to 65535

SQL query to get most recent row for each instance of a given key

Try this:

Select u.[username]
      ,u.[ip]
      ,q.[time_stamp]
From [users] As u
Inner Join (
    Select [username]
          ,max(time_stamp) as [time_stamp]
    From [users]
    Group By [username]) As [q]
On u.username = q.username
And u.time_stamp = q.time_stamp

How to send multiple data fields via Ajax?

I am a beginner at ajax but I think to use this "data: {status: status, name: name}" method datatype must be set to JSON i.e

$.ajax({
type: "POST",
dataType: "json",
url: "ajax/activity_save.php",
data: {status: status, name: name},

Reading output of a command into an array in Bash

Here is an example. Imagine that you are going to put the files and directory names (under the current folder) to an array and count its items. The script would be like;

my_array=( `ls` )
my_array_length=${#my_array[@]}
echo $my_array_length

Or, you can iterate over this array by adding the following script:

for element in "${my_array[@]}"
do
   echo "${element}"
done

Please note that this is the core concept and the input is considered to be sanitized before, i.e. removing extra characters, handling empty Strings, and etc. (which is out of the topic of this thread).

UIButton Image + Text IOS

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
button.imageView.image = [UIImage imageNamed:@"your image name here"];
button.titleLabel.text = @"your text here";

but following code will show label above and image in background

UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
button.background.image = [UIImage imageNamed:@"your image name here"];
button.titleLabel.text = @"your text here";

There is no need to use label and button in same control because UIButton has UILabel and UIimageview properties.

How to style a clicked button in CSS

If you just want the button to have different styling while the mouse is pressed you can use the :active pseudo class.

.button:active {
}

If on the other hand you want the style to stay after clicking you will have to use javascript.

python int( ) function

Use float() in place of int() so that your program can handle decimal points. Also, don't use next as it's a built-in Python function, next().

Also you code as posted is missing import sys and the definition for dead

How to extract text from a string using sed?

Try using rextract. It will let you extract text using a regular expression and reformat it.

Example:

$ echo "This is 02G05 a test string 20-Jul-2012" | ./rextract '([\d]+G[\d]+)' '${1}'

2G05

Copy table to a different database on a different SQL Server

SQL Server(2012) provides another way to generate script for the SQL Server databases with its objects and data. This script can be used to copy the tables’ schema and data from the source database to the destination one in our case.

  1. Using the SQL Server Management Studio, right-click on the source database from the object explorer, then from Tasks choose Generate Scripts. enter image description here
  2. In the Choose objects window, choose Select Specific Database Objects to specify the tables that you will generate script for, then choose the tables by ticking beside each one of it. Click Next. enter image description here
  3. In the Set Scripting Options window, specify the path where you will save the generated script file, and click Advanced. enter image description here
  4. From the appeared Advanced Scripting Options window, specify Schema and Data as Types of Data to Script. You can decide from here if you want to script the indexes and keys in your tables. Click OK. enter image description here Getting back to the Advanced Scripting Options window, click Next.
  5. Review the Summary window and click Next. enter image description here
  6. You can monitor the progress from the Save or Publish Scripts window. If there is no error click Finish and you will find the script file in the specified path. enter image description here

SQL Scripting method is useful to generate one single script for the tables’ schema and data, including the indexes and keys. But again this method doesn’t generate the tables’ creation script in the correct order if there are relations between the tables.

Compare and contrast REST and SOAP web services?

SOAP uses WSDL for communication btw consumer and provider, whereas REST just uses XML or JSON to send and receive data

WSDL defines contract between client and service and is static by its nature. In case of REST contract is somewhat complicated and is defined by HTTP, URI, Media Formats and Application Specific Coordination Protocol. It's highly dynamic unlike WSDL.

SOAP doesn't return human readable result, whilst REST result is readable with is just plain XML or JSON

This is not true. Plain XML or JSON are not RESTful at all. None of them define any controls(i.e. links and link relations, method information, encoding information etc...) which is against REST as far as messages must be self contained and coordinate interaction between agent/client and service.

With links + semantic link relations clients should be able to determine what is next interaction step and follow these links and continue communication with service.

It is not necessary that messages be human readable, it's possible to use cryptic format and build perfectly valid REST applications. It doesn't matter whether message is human readable or not.

Thus, plain XML(application/xml) or JSON(application/json) are not sufficient formats for building REST applications. It's always reasonable to use subset of these generic media types which have strong semantic meaning and offer enough control information(links etc...) to coordinate interactions between client and server.

REST is over only HTTP

Not true, HTTP is most widely used and when we talk about REST web services we just assume HTTP. HTTP defines interface with it's methods(GET, POST, PUT, DELETE, PATCH etc) and various headers which can be used uniformly for interacting with resources. This uniformity can be achieved with other protocols as well.

P.S. Very simple, yet very interesting explanation of REST: http://www.looah.com/source/view/2284

Classes vs. Modules in VB.NET

Modules are by no means deprecated and are used heavily in the VB language. It's the only way for instance to implement an extension method in VB.Net.

There is one huge difference between Modules and Classes with Static Members. Any method defined on a Module is globally accessible as long as the Module is available in the current namespace. In effect a Module allows you to define global methods. This is something that a class with only shared members cannot do.

Here's a quick example that I use a lot when writing VB code that interops with raw COM interfaces.

Module Interop
  Public Function Succeeded(ByVal hr as Integer) As Boolean
    ...
  End Function

  Public Function Failed(ByVal hr As Integer) As Boolean
    ...
  End Function
End Module

Class SomeClass
  Sub Foo()
    Dim hr = CallSomeHrMethod()
    if Succeeded(hr) then
      ..
    End If
  End Sub
End Class

How to run an external program, e.g. notepad, using hyperlink?

I've wrote a small extension to do so.

Since you are creating the page using C# you may want to implement this:

https://github.com/felix-d-git/DesktopAppLink

Basically u are creating some registry entries to parse the links you click in your html page.

The browser will then ask to open the specified app.

C#:

DesktopAppLink.CreateLink("applink.sample", "\"<path to exe>\"", "");

HTML:

<a href="applink.sample:">Run Desktop App</a>

Result:

enter image description here

Read specific columns with pandas or other python module

Above answers are in python2. So for python 3 users I am giving this answer. You can use the bellow code:

import pandas as pd
fields = ['star_name', 'ra']

df = pd.read_csv('data.csv', skipinitialspace=True, usecols=fields)
# See the keys
print(df.keys())
# See content in 'star_name'
print(df.star_name)

'negative' pattern matching in python

and(re.search("bla_bla_pattern", str_item, re.IGNORECASE) == None)

is working.

Tried to Load Angular More Than Once

Capitalization matters as well! Inside my directive, I tried specifying:

templateUrl: 'Views/mytemplate'

and got the "more than once" warning. The warning disappeared when I changed it to:

templateUrl: 'views/mytemplate'

Correct me, but I think this happened because page that I placed the directive on was under "views" and not "Views" in the route config function.

how to fix java.lang.IndexOutOfBoundsException

This error happens because your list lstpp is empty (Nothing at index 0). So either there is a bug in your getResult() function, or the empty list is normal and you need to handle this case (By checking the size of the list before, or catching the exception).

Reducing MongoDB database file size

If you need to run a full repair, use the repairpath option. Point it to a disk with more available space.

For example, on my Mac I've used:

mongod --config /usr/local/etc/mongod.conf --repair --repairpath /Volumes/X/mongo_repair

Update: Per MongoDB Core Server Ticket 4266, you may need to add --nojournal to avoid an error:

mongod --config /usr/local/etc/mongod.conf --repair --repairpath /Volumes/X/mongo_repair --nojournal

What is the proper #include for the function 'sleep()'?

this is what I use for a cross-platform code:

#ifdef _WIN32
#include <Windows.h>
#else
#include <unistd.h>
#endif

int main()
{
  pollingDelay = 100
  //do stuff

  //sleep:
  #ifdef _WIN32
  Sleep(pollingDelay);
  #else
  usleep(pollingDelay*1000);  /* sleep for 100 milliSeconds */
  #endif

  //do stuff again
  return 0;
}

Pycharm: run only part of my Python file

You can select a code snippet and use right click menu to choose the action "Execute Selection in console".

SQL Server IF NOT EXISTS Usage?

Have you verified that there is in fact a row where Staff_Id = @PersonID? What you've posted works fine in a test script, assuming the row exists. If you comment out the insert statement, then the error is raised.

set nocount on

create table Timesheet_Hours (Staff_Id int, BookedHours int, Posted_Flag bit)

insert into Timesheet_Hours (Staff_Id, BookedHours, Posted_Flag) values (1, 5.5, 0)

declare @PersonID int
set @PersonID = 1

IF EXISTS    
    (
    SELECT 1    
    FROM Timesheet_Hours    
    WHERE Posted_Flag = 1    
        AND Staff_Id = @PersonID    
    )    
    BEGIN
        RAISERROR('Timesheets have already been posted!', 16, 1)
        ROLLBACK TRAN
    END
ELSE
    IF NOT EXISTS
        (
        SELECT 1
        FROM Timesheet_Hours
        WHERE Staff_Id = @PersonID
        )
        BEGIN
            RAISERROR('Default list has not been loaded!', 16, 1)
            ROLLBACK TRAN
        END
    ELSE
        print 'No problems here'

drop table Timesheet_Hours

Instantiating a generic type

No, and the fact that you want to seems like a bad idea. Do you really need a default constructor like this?

Pull all images from a specified directory and then display them

You can display all image from a folder using simple php script. Suppose folder name “images” and put some image in this folder and then use any text editor and paste this code and run this script. This is php code

    <?php
     $files = glob("images/*.*");
     for ($i=0; $i<count($files); $i++)
      {
        $image = $files[$i];
        $supported_file = array(
                'gif',
                'jpg',
                'jpeg',
                'png'
         );

         $ext = strtolower(pathinfo($image, PATHINFO_EXTENSION));
         if (in_array($ext, $supported_file)) {
            echo basename($image)."<br />"; // show only image name if you want to show full path then use this code // echo $image."<br />";
             echo '<img src="'.$image .'" alt="Random image" />'."<br /><br />";
            } else {
                continue;
            }
          }
       ?>

if you do not check image type then use this code

<?php
$files = glob("images/*.*");
for ($i = 0; $i < count($files); $i++) {
    $image = $files[$i];
    echo basename($image) . "<br />"; // show only image name if you want to show full path then use this code // echo $image."<br />";
    echo '<img src="' . $image . '" alt="Random image" />' . "<br /><br />";

}
?>

Changing CSS Values with Javascript

I've never seen any practical use of this, but you should probably consider DOM stylesheets. However, I honestly think that's overkill.

If you simply want to get the width and height of an element, irrespective of where the dimensions are being applied from, just use element.offsetWidth and element.offsetHeight.

org.apache.tomcat.util.bcel.classfile.ClassFormatException: Invalid byte tag in constant pool: 15

I got similar error (org.aspectj.apache.bcel.classfile.ClassFormatException: Invalid byte tag in constant pool: 15) while using aspectj 1.8.13. Solution was to align all compilation into jdk 8 and being careful not to put aspectj library's (1.6.13 for instance) other versions to buildpath/classpath.

Fully backup a git repo?

Whats about just make a clone of it?

git clone --mirror other/repo.git

Every repository is a backup of its remote.

How to 'bulk update' with Django?

If you want to set the same value on a collection of rows, you can use the update() method combined with any query term to update all rows in one query:

some_list = ModelClass.objects.filter(some condition).values('id')
ModelClass.objects.filter(pk__in=some_list).update(foo=bar)

If you want to update a collection of rows with different values depending on some condition, you can in best case batch the updates according to values. Let's say you have 1000 rows where you want to set a column to one of X values, then you could prepare the batches beforehand and then only run X update-queries (each essentially having the form of the first example above) + the initial SELECT-query.

If every row requires a unique value there is no way to avoid one query per update. Perhaps look into other architectures like CQRS/Event sourcing if you need performance in this latter case.

The type java.io.ObjectInputStream cannot be resolved. It is indirectly referenced from required .class files

You simply need to upgrade your Tomcat version, to Tomcat 8.0.xx. Java8 <-> Tomcat8

This is the configuration that I have been using and it has always worked out well JDK version Tomcat versions

How to choose an AES encryption mode (CBC ECB CTR OCB CFB)?

Please consider long and hard if you can't get around implementing your own cryptography

The ugly truth of the matter is that if you are asking this question you will probably not be able to design and implement a secure system.

Let me illustrate my point: Imagine you are building a web application and you need to store some session data. You could assign each user a session ID and store the session data on the server in a hash map mapping session ID to session data. But then you have to deal with this pesky state on the server and if at some point you need more than one server things will get messy. So instead you have the idea to store the session data in a cookie on the client side. You will encrypt it of course so the user cannot read and manipulate the data. So what mode should you use? Coming here you read the top answer (sorry for singling you out myforwik). The first one covered - ECB - is not for you, you want to encrypt more than one block, the next one - CBC - sounds good and you don't need the parallelism of CTR, you don't need random access, so no XTS and patents are a PITA, so no OCB. Using your crypto library you realize that you need some padding because you can only encrypt multiples of the block size. You choose PKCS7 because it was defined in some serious cryptography standards. After reading somewhere that CBC is provably secure if used with a random IV and a secure block cipher, you rest at ease even though you are storing your sensitive data on the client side.

Years later after your service has indeed grown to significant size, an IT security specialist contacts you in a responsible disclosure. She's telling you that she can decrypt all your cookies using a padding oracle attack, because your code produces an error page if the padding is somehow broken.

This is not a hypothetical scenario: Microsoft had this exact flaw in ASP.NET until a few years ago.

The problem is there are a lot of pitfalls regarding cryptography and it is extremely easy to build a system that looks secure for the layman but is trivial to break for a knowledgeable attacker.

What to do if you need to encrypt data

For live connections use TLS (be sure to check the hostname of the certificate and the issuer chain). If you can't use TLS, look for the highest level API your system has to offer for your task and be sure you understand the guarantees it offers and more important what it does not guarantee. For the example above a framework like Play offers client side storage facilities, it does not invalidate the stored data after some time, though, and if you changed the client side state, an attacker can restore a previous state without you noticing.

If there is no high level abstraction available use a high level crypto library. A prominent example is NaCl and a portable implementation with many language bindings is Sodium. Using such a library you do not have to care about encryption modes etc. but you have to be even more careful about the usage details than with a higher level abstraction, like never using a nonce twice. For custom protocol building (say you want something like TLS, but not over TCP or UDP) there are frameworks like Noise and associated implementations that do most of the heavy lifting for you, but their flexibility also means there is a lot of room for error, if you don't understand in depth what all the components do.

If for some reason you cannot use a high level crypto library, for example because you need to interact with existing system in a specific way, there is no way around educating yourself thoroughly. I recommend reading Cryptography Engineering by Ferguson, Kohno and Schneier. Please don't fool yourself into believing you can build a secure system without the necessary background. Cryptography is extremely subtle and it's nigh impossible to test the security of a system.

Comparison of the modes

Encryption only:

  • Modes that require padding: Like in the example, padding can generally be dangerous because it opens up the possibility of padding oracle attacks. The easiest defense is to authenticate every message before decryption. See below.
    • ECB encrypts each block of data independently and the same plaintext block will result in the same ciphertext block. Take a look at the ECB encrypted Tux image on the ECB Wikipedia page to see why this is a serious problem. I don't know of any use case where ECB would be acceptable.
    • CBC has an IV and thus needs randomness every time a message is encrypted, changing a part of the message requires re-encrypting everything after the change, transmission errors in one ciphertext block completely destroy the plaintext and change the decryption of the next block, decryption can be parallelized / encryption can't, the plaintext is malleable to a certain degree - this can be a problem.
  • Stream cipher modes: These modes generate a pseudo random stream of data that may or may not depend the plaintext. Similarly to stream ciphers generally, the generated pseudo random stream is XORed with the plaintext to generate the ciphertext. As you can use as many bits of the random stream as you like you don't need padding at all. Disadvantage of this simplicity is that the encryption is completely malleable, meaning that the decryption can be changed by an attacker in any way he likes as for a plaintext p1, a ciphertext c1 and a pseudo random stream r and attacker can choose a difference d such that the decryption of a ciphertext c2=c1?d is p2 = p1?d, as p2 = c2?r = (c1 ? d) ? r = d ? (c1 ? r). Also the same pseudo random stream must never be used twice as for two ciphertexts c1=p1?r and c2=p2?r, an attacker can compute the xor of the two plaintexts as c1?c2=p1?r?p2?r=p1?p2. That also means that changing the message requires complete reencryption, if the original message could have been obtained by an attacker. All of the following steam cipher modes only need the encryption operation of the block cipher, so depending on the cipher this might save some (silicon or machine code) space in extremely constricted environments.
    • CTR is simple, it creates a pseudo random stream that is independent of the plaintext, different pseudo random streams are obtained by counting up from different nonces/IVs which are multiplied by a maximum message length so that overlap is prevented, using nonces message encryption is possible without per message randomness, decryption and encryption are completed parallelizable, transmission errors only effect the wrong bits and nothing more
    • OFB also creates a pseudo random stream independent of the plaintext, different pseudo random streams are obtained by starting with a different nonce or random IV for every message, neither encryption nor decryption is parallelizable, as with CTR using nonces message encryption is possible without per message randomness, as with CTR transmission errors only effect the wrong bits and nothing more
    • CFB's pseudo random stream depends on the plaintext, a different nonce or random IV is needed for every message, like with CTR and OFB using nonces message encryption is possible without per message randomness, decryption is parallelizable / encryption is not, transmission errors completely destroy the following block, but only effect the wrong bits in the current block
  • Disk encryption modes: These modes are specialized to encrypt data below the file system abstraction. For efficiency reasons changing some data on the disc must only require the rewrite of at most one disc block (512 bytes or 4kib). They are out of scope of this answer as they have vastly different usage scenarios than the other. Don't use them for anything except block level disc encryption. Some members: XEX, XTS, LRW.

Authenticated encryption:

To prevent padding oracle attacks and changes to the ciphertext, one can compute a message authentication code (MAC) on the ciphertext and only decrypt it if it has not been tampered with. This is called encrypt-then-mac and should be preferred to any other order. Except for very few use cases authenticity is as important as confidentiality (the latter of which is the aim of encryption). Authenticated encryption schemes (with associated data (AEAD)) combine the two part process of encryption and authentication into one block cipher mode that also produces an authentication tag in the process. In most cases this results in speed improvement.

  • CCM is a simple combination of CTR mode and a CBC-MAC. Using two block cipher encryptions per block it is very slow.
  • OCB is faster but encumbered by patents. For free (as in freedom) or non-military software the patent holder has granted a free license, though.
  • GCM is a very fast but arguably complex combination of CTR mode and GHASH, a MAC over the Galois field with 2^128 elements. Its wide use in important network standards like TLS 1.2 is reflected by a special instruction Intel has introduced to speed up the calculation of GHASH.

Recommendation:

Considering the importance of authentication I would recommend the following two block cipher modes for most use cases (except for disk encryption purposes): If the data is authenticated by an asymmetric signature use CBC, otherwise use GCM.

Adding custom HTTP headers using JavaScript

As already said, the easiest way is to use querystring.

But if you cannot, because of security reason, you should consider using cookies.

Applying a single font to an entire website with CSS

Please place this in the head of your Page(s) if the "body" needs the use of 1 and the same font:

<style type="text/css">
body {font-family:FONT-NAME ;
     }
</style>

Everything between the tags <body> and </body>will have the same font

Angular2 dynamic change CSS property

You don't have any example code but I assume you want to do something like this?

@View({
directives: [NgClass],
styles: [`
    .${TodoModel.COMPLETED}  {
        text-decoration: line-through;
    }
    .${TodoModel.STARTED} {
        color: green;
    }
`],
template: `<div>
                <span [ng-class]="todo.status" >{{todo.title}}</span>
                <button (click)="todo.toggle()" >Toggle status</button>
            </div>`
})

You assign ng-class to a variable which is dynamic (a property of a model called TodoModel as you can guess).

todo.toggle() is changing the value of todo.status and there for the class of the input is changing.

This is an example for class name but actually you could do the same think for css properties.

I hope this is what you meant.

This example is taken for the great egghead tutorial here.

Setting an image for a UIButton in code

UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
btn.frame = CGRectMake(0, 0, 150, 44);
[btn setBackgroundImage:[UIImage imageNamed:@"buttonimage.png"] 
               forState:UIControlStateNormal];
[btn addTarget:self 
     action:@selector(btnSendComment_pressed:) 
     forControlEvents:UIControlEventTouchUpInside];
[self.view addSubview:btn];

How to add a delay for a 2 or 3 seconds

For 2.3 seconds you should do:

System.Threading.Thread.Sleep(2300);

What is the most effective way for float and double comparison?

It depends on how precise you want the comparison to be. If you want to compare for exactly the same number, then just go with ==. (You almost never want to do this unless you actually want exactly the same number.) On any decent platform you can also do the following:

diff= a - b; return fabs(diff)<EPSILON;

as fabs tends to be pretty fast. By pretty fast I mean it is basically a bitwise AND, so it better be fast.

And integer tricks for comparing doubles and floats are nice but tend to make it more difficult for the various CPU pipelines to handle effectively. And it's definitely not faster on certain in-order architectures these days due to using the stack as a temporary storage area for values that are being used frequently. (Load-hit-store for those who care.)

How do I install imagemagick with homebrew?

You could do:

brew reinstall php55-imagick

Where php55 is your PHP version.

TERM environment variable not set

Using a terminal command i.e. "clear", in a script called from cron (no terminal) will trigger this error message. In your particular script, the smbmount command expects a terminal in which case the work-arounds above are appropriate.

Pass variables between two PHP pages without using a form or the URL of page

Use Sessions.

Page1:

session_start();
$_SESSION['message'] = "Some message"

Page2:

session_start();
var_dump($_SESSION['message']);

How to wait in a batch script?

You can ping an address that doesn't exist and specify the desired timeout:

ping 192.0.2.2 -n 1 -w 10000 > nul

And since the address does not exist, it'll wait 10,000 ms (10 seconds) and return.

  • The -w 10000 part specifies the desired timeout in milliseconds.
  • The -n 1 part tells ping that it should only try once (normally it'd try 4 times).
  • The > nul part is appended so the ping command doesn't output anything to screen.

You can easily make a sleep command yourself by creating a sleep.bat somewhere in your PATH and using the above technique:

rem SLEEP.BAT - sleeps by the supplied number of seconds

@ping 192.0.2.2 -n 1 -w %1000 > nul

NOTE (September 2002): The 192.0.2.x address is reserved as per RFC 3330 so it definitely will not exist in the real world. Quoting from the spec:

192.0.2.0/24 - This block is assigned as "TEST-NET" for use in documentation and example code. It is often used in conjunction with domain names example.com or example.net in vendor and protocol documentation. Addresses within this block should not appear on the public Internet.

How to write a multiline Jinja statement

According to the documentation: https://jinja.palletsprojects.com/en/2.10.x/templates/#line-statements you may use multi-line statements as long as the code has parens/brackets around it. Example:

{% if ( (foo == 'foo' or bar == 'bar') and 
        (fooo == 'fooo' or baar == 'baar') ) %}
    <li>some text</li>
{% endif %}

Edit: Using line_statement_prefix = '#'* the code would look like this:

# if ( (foo == 'foo' or bar == 'bar') and 
       (fooo == 'fooo' or baar == 'baar') )
    <li>some text</li>
# endif

*Here's an example of how you'd specify the line_statement_prefix in the Environment:

from jinja2 import Environment, PackageLoader, select_autoescape
env = Environment(
    loader=PackageLoader('yourapplication', 'templates'),
    autoescape=select_autoescape(['html', 'xml']),
    line_statement_prefix='#'
)

Or using Flask:

from flask import Flask
app = Flask(__name__, instance_relative_config=True, static_folder='static')
app.jinja_env.filters['zip'] = zip
app.jinja_env.line_statement_prefix = '#'

iOS application: how to clear notifications?

When you have repeated notifications at future, you do not want to cancel those notifications, you can clear the item in notification center by:

func clearNotificationCenter() {
    UIApplication.sharedApplication().applicationIconBadgeNumber = 1
    UIApplication.sharedApplication().applicationIconBadgeNumber = 0
}

You cannot clear notification when your app is open in the foreground by calling the method below immediately after receiving local notification, otherwise you will receive tens of hundreds of notifications. Maybe because the same notification apply again, and now is the time to fire, so you keep fire, apply again, fire, apply....:

[UIApplication sharedApplication].scheduledLocalNotifications = [UIApplication sharedApplication].scheduledLocalNotifications;

Remove Rows From Data Frame where a Row matches a String

I had a column(A) in a data frame with 3 values in it (yes, no, unknown). I wanted to filter only those rows which had a value "yes" for which this is the code, hope this will help you guys as well --

df <- df [(!(df$A=="no") & !(df$A=="unknown")),]

How to pass multiple parameters from ajax to mvc controller?

Try this;

function X (id,parameter1,parameter2,...) {
    $.ajax({

            url: '@Url.Action("Actionre", "controller")',+ id,
            type: "Get",
            data: { parameter1: parameter1, parameter2: parameter2,...}

    }).done(function(result) {

        your code...
    });
}

So controller method would looks like :

public ActionResult ActionName(id,parameter1, parameter2,...)
{
   Your Code .......
}

How to track down access violation "at address 00000000"

Here is a real quick temporary fix, at least until you reboot again but it will get rid of a persistent access. I had installed a program that works fine but for some reason, there is a point that did not install correctly in the right file. So when it cannot access the file, it pops up the access denied but instead of just one, it keeps trying to start it up so even searching for the location to stop it permanently, it will continue to pop up more and more and more every 3 seconds. To stop that from happening at least temporarily, do the following...

  1. Ctl+Alt+Del
  2. Open your Task Manager
  3. Note down the name of the program that's requesting access (you may see it in your application's tab)
  4. Click on your Processes tab
  5. Scroll through until you find the Process matching the program name and click on it
  6. Click End Process

That will prevent the window from persistently popping up, at least until you reboot. I know that does not solve the problem but like anything, there is a process of elimination and this step here will at least make it a little less annoying.

Where can I find decent visio templates/diagrams for software architecture?

For SOA system architecture, I use the SOACP Visio stencil. It provides the symbols that are used in Thomas Erl's SOA book series.

I use the Visio Network and Database stencils to model most other requirements.

Cut Java String at a number of character

Use substring

String strOut = "abcdefghijklmnopqrtuvwxyz"
String result = strOut.substring(0, 8) + "...";// count start in 0 and 8 is excluded
System.out.pritnln(result);

Note: substring(int first, int second) takes two parameters. The first is inclusive and the second is exclusive.

insert vertical divider line between two nested divs, not full height

Try this. I set the blue box to float right, gave left and right a fixed height, and added a white border on the right of the left div. Also added rounded corners to more match your example (These won't work in ie 8 or less). I also took out the position: relative. You don't need it. Block level elements are set to position relative by default.

See it here: http://jsfiddle.net/ZSgLJ/

#left {
  float: left;
  width: 44%;
  margin: 0;
  padding: 0;
  border-right: 1px solid white;
  height:400px;
}

#right {
  position: relative;
  float: right;
  width: 49%;
  margin: 0;
  padding: 0;
  height:400px;
}

#blue_box {
  background-color:blue;
  border-radius: 10px;
  -moz-border-radius:10px;
  -webkit-border-radius: 10px;
  width: 45%;
  min-width: 400px;
  max-width: 600px;
  padding: 2%;
  float: right;
}

Peak-finding algorithm for Python/SciPy

First things first, the definition of "peak" is vague if without further specifications. For example, for the following series, would you call 5-4-5 one peak or two?

1-2-1-2-1-1-5-4-5-1-1-5-1

In this case, you'll need at least two thresholds: 1) a high threshold only above which can an extreme value register as a peak; and 2) a low threshold so that extreme values separated by small values below it will become two peaks.

Peak detection is a well-studied topic in Extreme Value Theory literature, also known as "declustering of extreme values". Its typical applications include identifying hazard events based on continuous readings of environmental variables e.g. analysing wind speed to detect storm events.

Using jQuery to center a DIV on the screen

I put a jquery plugin here

VERY SHORT VERSION

$('#myDiv').css({top:'50%',left:'50%',margin:'-'+($('#myDiv').height() / 2)+'px 0 0 -'+($('#myDiv').width() / 2)+'px'});

SHORT VERSION

(function($){
    $.fn.extend({
        center: function () {
            return this.each(function() {
                var top = ($(window).height() - $(this).outerHeight()) / 2;
                var left = ($(window).width() - $(this).outerWidth()) / 2;
                $(this).css({position:'absolute', margin:0, top: (top > 0 ? top : 0)+'px', left: (left > 0 ? left : 0)+'px'});
            });
        }
    }); 
})(jQuery);

Activated by this code :

$('#mainDiv').center();

PLUGIN VERSION

(function($){
     $.fn.extend({
          center: function (options) {
               var options =  $.extend({ // Default values
                    inside:window, // element, center into window
                    transition: 0, // millisecond, transition time
                    minX:0, // pixel, minimum left element value
                    minY:0, // pixel, minimum top element value
                    withScrolling:true, // booleen, take care of the scrollbar (scrollTop)
                    vertical:true, // booleen, center vertical
                    horizontal:true // booleen, center horizontal
               }, options);
               return this.each(function() {
                    var props = {position:'absolute'};
                    if (options.vertical) {
                         var top = ($(options.inside).height() - $(this).outerHeight()) / 2;
                         if (options.withScrolling) top += $(options.inside).scrollTop() || 0;
                         top = (top > options.minY ? top : options.minY);
                         $.extend(props, {top: top+'px'});
                    }
                    if (options.horizontal) {
                          var left = ($(options.inside).width() - $(this).outerWidth()) / 2;
                          if (options.withScrolling) left += $(options.inside).scrollLeft() || 0;
                          left = (left > options.minX ? left : options.minX);
                          $.extend(props, {left: left+'px'});
                    }
                    if (options.transition > 0) $(this).animate(props, options.transition);
                    else $(this).css(props);
                    return $(this);
               });
          }
     });
})(jQuery);

Activated by this code :

$(document).ready(function(){
    $('#mainDiv').center();
    $(window).bind('resize', function() {
        $('#mainDiv').center({transition:300});
    });
);

is that right ?

UPDATE :

From CSS-Tricks

.center {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%); /* Yep! */
  width: 48%;
  height: 59%;
}

How to select a div element in the code-behind page?

@CarlosLanderas is correct depending on where you've placed the DIV control. The DIV by the way is not technically an ASP control, which is why you cannot find it directly like other controls. But the best way around this is to turn it into an ASP control.

Use asp:Panel instead. It is rendered into a <div> tag anyway...

<asp:Panel id="divSubmitted" runat="server" style="text-align:center" visible="false">
   <asp:Label ID="labSubmitted" runat="server" Text="Roll Call Submitted"></asp:Label>
</asp:Panel>

And in code behind, simply find the Panel control as per normal...

Panel DivCtl1 = (Panel)gvRollCall.FooterRow.FindControl("divSubmitted");
if (DivCtl1 != null)
    DivCtl1.Visible = true;

Please note that I've used FooterRow, as my "psuedo div" is inside the footer row of a Gridview control.

Good coding!

How to return a string value from a Bash function

The most straightforward and robust solution is to use command substitution, as other people wrote:

assign()
{
    local x
    x="Test"
    echo "$x"
}

x=$(assign) # This assigns string "Test" to x

The downside is performance as this requires a separate process.

The other technique suggested in this topic, namely passing the name of a variable to assign to as an argument, has side effects, and I wouldn't recommend it in its basic form. The problem is that you will probably need some variables in the function to calculate the return value, and it may happen that the name of the variable intended to store the return value will interfere with one of them:

assign()
{
    local x
    x="Test"
    eval "$1=\$x"
}

assign y # This assigns string "Test" to y, as expected

assign x # This will NOT assign anything to x in this scope
         # because the name "x" is declared as local inside the function

You might, of course, not declare internal variables of the function as local, but you really should always do it as otherwise you may, on the other hand, accidentally overwrite an unrelated variable from the parent scope if there is one with the same name.

One possible workaround is an explicit declaration of the passed variable as global:

assign()
{
    local x
    eval declare -g $1
    x="Test"
    eval "$1=\$x"
}

If name "x" is passed as an argument, the second row of the function body will overwrite the previous local declaration. But the names themselves might still interfere, so if you intend to use the value previously stored in the passed variable prior to write the return value there, be aware that you must copy it into another local variable at the very beginning; otherwise the result will be unpredictable! Besides, this will only work in the most recent version of BASH, namely 4.2. More portable code might utilize explicit conditional constructs with the same effect:

assign()
{
    if [[ $1 != x ]]; then
      local x
    fi
    x="Test"
    eval "$1=\$x"
}

Perhaps the most elegant solution is just to reserve one global name for function return values and use it consistently in every function you write.

"webxml attribute is required" error in Maven

This is because you have not included web.xml in your web project and trying to build war using maven. To resolve this error, you need to set the failOnMissingWebXml to false in pom.xml file.

For example:

<properties>
    <failOnMissingWebXml>false</failOnMissingWebXml>   
</properties>

Please see the blog for more details: https://ankurjain26.blogspot.in/2017/05/error-assembling-war-webxml-attribute.html

JavaScript - Hide a Div at startup (load)

Barring the CSS solution. The fastest possible way is to hide it immediatly with a script.

<div id="hideme"></div>
<script type="text/javascript">
    $("#hideme").hide();
</script>

In this case I would recommend the CSS solution by Vega. But if you need something more complex (like an animation) you can use this approach.

This has some complications (see comments below). If you want this piece of script to really run as fast as possible you can't use jQuery, use native JS only and defer loading of all other scripts.

Converting Long to Date in Java returns 1970

Those are probably timestamps in seconds and not in milliseconds which is required for the java new Date(long) constructor. Just multiply them by 1000 and you should be allright.

What is the best way to get the count/length/size of an iterator?

If you've just got the iterator then that's what you'll have to do - it doesn't know how many items it's got left to iterate over, so you can't query it for that result. There are utility methods that will seem to do this efficiently (such as Iterators.size() in Guava), but underneath they're just consuming the iterator and counting as they go, the same as in your example.

However, many iterators come from collections, which you can often query for their size. And if it's a user made class you're getting the iterator for, you could look to provide a size() method on that class.

In short, in the situation where you only have the iterator then there's no better way, but much more often than not you have access to the underlying collection or object from which you may be able to get the size directly.

How to change color of SVG image using CSS (jQuery SVG image replacement)?

If you can include files (PHP include or include via your CMS of choice) in your page, you can add the SVG code and include it into your page. This works the same as pasting the SVG source into the page, but makes the page markup cleaner.

The benefit is that you can target parts of your SVG via CSS for hover -- no javascript required.

http://codepen.io/chriscoyier/pen/evcBu

You just have to use a CSS rule like this:

#pathidorclass:hover { fill: #303 !important; }

Note that the !important bit is necessary to override the fill color.

Drawing a line/path on Google Maps

public class MainActivity extends FragmentActivity  {


  List<Overlay> mapOverlays;
  GeoPoint point1, point2;
  LocationManager locManager;
  Drawable drawable;
  Document document;
  GMapV2GetRouteDirection v2GetRouteDirection;
  LatLng fromPosition;
  LatLng toPosition;
  GoogleMap mGoogleMap;
  MarkerOptions markerOptions;
  Location location ;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        v2GetRouteDirection = new GMapV2GetRouteDirection();
      SupportMapFragment supportMapFragment = (SupportMapFragment) getSupportFragmentManager()
        .findFragmentById(R.id.map);
        mGoogleMap = supportMapFragment.getMap();

        // Enabling MyLocation in Google Map
        mGoogleMap.setMyLocationEnabled(true);
        mGoogleMap.getUiSettings().setZoomControlsEnabled(true);
        mGoogleMap.getUiSettings().setCompassEnabled(true);
        mGoogleMap.getUiSettings().setMyLocationButtonEnabled(true);
        mGoogleMap.getUiSettings().setAllGesturesEnabled(true);
        mGoogleMap.setTrafficEnabled(true);
        mGoogleMap.animateCamera(CameraUpdateFactory.zoomTo(12));
        markerOptions = new MarkerOptions();
        fromPosition = new LatLng(11.663837, 78.147297);
        toPosition = new LatLng(11.723512, 78.466287);
        GetRouteTask getRoute = new GetRouteTask();
        getRoute.execute();
  }
  /**
   *
   * @author VIJAYAKUMAR M
   * This class Get Route on the map
   *
   */
  private class GetRouteTask extends AsyncTask<String, Void, String> {

        private ProgressDialog Dialog;
        String response = "";
        @Override
        protected void onPreExecute() {
              Dialog = new ProgressDialog(MainActivity.this);
              Dialog.setMessage("Loading route...");
              Dialog.show();
        }

        @Override
        protected String doInBackground(String... urls) {
              //Get All Route values
                         document = v2GetRouteDirection.getDocument(fromPosition, toPosition,          GMapV2GetRouteDirection.MODE_DRIVING);
                    response = "Success";
              return response;

        }

        @Override
        protected void onPostExecute(String result) {
              mGoogleMap.clear();
              if(response.equalsIgnoreCase("Success")){
              ArrayList<LatLng> directionPoint = v2GetRouteDirection.getDirection(document);
              PolylineOptions rectLine = new PolylineOptions().width(10).color(
                          Color.RED);

              for (int i = 0; i < directionPoint.size(); i++) {
                    rectLine.add(directionPoint.get(i));
              }
              // Adding route on the map
              mGoogleMap.addPolyline(rectLine);
              markerOptions.position(toPosition);
              markerOptions.draggable(true);
              mGoogleMap.addMarker(markerOptions);

              }

              Dialog.dismiss();
        }
  }
  @Override
  protected void onStop() {
        super.onStop();
        finish();
    }
 }

Route Helper class

 public class GMapV2GetRouteDirection {
  public final static String MODE_DRIVING = "driving";
  public final static String MODE_WALKING = "walking";

  public GMapV2GetRouteDirection() { }

  public Document getDocument(LatLng start, LatLng end, String mode) {
    String url = "http://maps.googleapis.com/maps/api/directions/xml?"
            + "origin=" + start.latitude + "," + start.longitude 
            + "&destination=" + end.latitude + "," + end.longitude
            + "&sensor=false&units=metric&mode=driving";

    try {
        HttpClient httpClient = new DefaultHttpClient();
        HttpContext localContext = new BasicHttpContext();
        HttpPost httpPost = new HttpPost(url);
        HttpResponse response = httpClient.execute(httpPost, localContext);
        InputStream in = response.getEntity().getContent();
        DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
        Document doc = builder.parse(in);
        return doc;
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
  }

  public String getDurationText (Document doc) {
    NodeList nl1 = doc.getElementsByTagName("duration");
    Node node1 = nl1.item(0);
    NodeList nl2 = node1.getChildNodes();
    Node node2 = nl2.item(getNodeIndex(nl2, "text"));
    Log.i("DurationText", node2.getTextContent());
    return node2.getTextContent();
 }

 public int getDurationValue (Document doc) {
    NodeList nl1 = doc.getElementsByTagName("duration");
    Node node1 = nl1.item(0);
    NodeList nl2 = node1.getChildNodes();
    Node node2 = nl2.item(getNodeIndex(nl2, "value"));
    Log.i("DurationValue", node2.getTextContent());
    return Integer.parseInt(node2.getTextContent());
  }

  public String getDistanceText (Document doc) {
    NodeList nl1 = doc.getElementsByTagName("distance");
    Node node1 = nl1.item(0);
    NodeList nl2 = node1.getChildNodes();
    Node node2 = nl2.item(getNodeIndex(nl2, "text"));
    Log.i("DistanceText", node2.getTextContent());
    return node2.getTextContent();
  }

  public int getDistanceValue (Document doc) {
    NodeList nl1 = doc.getElementsByTagName("distance");
    Node node1 = nl1.item(0);
    NodeList nl2 = node1.getChildNodes();
    Node node2 = nl2.item(getNodeIndex(nl2, "value"));
    Log.i("DistanceValue", node2.getTextContent());
    return Integer.parseInt(node2.getTextContent());
  }

  public String getStartAddress (Document doc) {
    NodeList nl1 = doc.getElementsByTagName("start_address");
    Node node1 = nl1.item(0);
    Log.i("StartAddress", node1.getTextContent());
    return node1.getTextContent();
  }

  public String getEndAddress (Document doc) {
    NodeList nl1 = doc.getElementsByTagName("end_address");
    Node node1 = nl1.item(0);
    Log.i("StartAddress", node1.getTextContent());
    return node1.getTextContent();
  }

  public String getCopyRights (Document doc) {
    NodeList nl1 = doc.getElementsByTagName("copyrights");
    Node node1 = nl1.item(0);
    Log.i("CopyRights", node1.getTextContent());
    return node1.getTextContent();
  }

   public ArrayList<LatLng> getDirection (Document doc) {
    NodeList nl1, nl2, nl3;
    ArrayList<LatLng> listGeopoints = new ArrayList<LatLng>();
    nl1 = doc.getElementsByTagName("step");
    if (nl1.getLength() > 0) {
        for (int i = 0; i < nl1.getLength(); i++) {
            Node node1 = nl1.item(i);
            nl2 = node1.getChildNodes();

            Node locationNode = nl2.item(getNodeIndex(nl2, "start_location"));
            nl3 = locationNode.getChildNodes();
            Node latNode = nl3.item(getNodeIndex(nl3, "lat"));
            double lat = Double.parseDouble(latNode.getTextContent());
            Node lngNode = nl3.item(getNodeIndex(nl3, "lng"));
            double lng = Double.parseDouble(lngNode.getTextContent());
            listGeopoints.add(new LatLng(lat, lng));

            locationNode = nl2.item(getNodeIndex(nl2, "polyline"));
            nl3 = locationNode.getChildNodes();
            latNode = nl3.item(getNodeIndex(nl3, "points"));
            ArrayList<LatLng> arr = decodePoly(latNode.getTextContent());
            for(int j = 0 ; j < arr.size() ; j++) {
                listGeopoints.add(new LatLng(arr.get(j).latitude, arr.get(j).longitude));
            }

            locationNode = nl2.item(getNodeIndex(nl2, "end_location"));
            nl3 = locationNode.getChildNodes();
            latNode = nl3.item(getNodeIndex(nl3, "lat"));
            lat = Double.parseDouble(latNode.getTextContent());
            lngNode = nl3.item(getNodeIndex(nl3, "lng"));
            lng = Double.parseDouble(lngNode.getTextContent());
            listGeopoints.add(new LatLng(lat, lng));
        }
    }

    return listGeopoints;
 }

 private int getNodeIndex(NodeList nl, String nodename) {
    for(int i = 0 ; i < nl.getLength() ; i++) {
        if(nl.item(i).getNodeName().equals(nodename))
            return i;
    }
    return -1;
 }

 private ArrayList<LatLng> decodePoly(String encoded) {
    ArrayList<LatLng> poly = new ArrayList<LatLng>();
    int index = 0, len = encoded.length();
    int lat = 0, lng = 0;
    while (index < len) {
        int b, shift = 0, result = 0;
        do {
            b = encoded.charAt(index++) - 63;
            result |= (b & 0x1f) << shift;
            shift += 5;
        } while (b >= 0x20);
        int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
        lat += dlat;
        shift = 0;
        result = 0;
        do {
            b = encoded.charAt(index++) - 63;
            result |= (b & 0x1f) << shift;
            shift += 5;
        } while (b >= 0x20);
        int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
        lng += dlng;

        LatLng position = new LatLng((double) lat / 1E5, (double) lng / 1E5);
        poly.add(position);
    }
    return poly;
  }
 }

How to smooth a curve in the right way?

Another option is to use KernelReg in statsmodels:

from statsmodels.nonparametric.kernel_regression import KernelReg
import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0,2*np.pi,100)
y = np.sin(x) + np.random.random(100) * 0.2

# The third parameter specifies the type of the variable x;
# 'c' stands for continuous
kr = KernelReg(y,x,'c')
plt.plot(x, y, '+')
y_pred, y_std = kr.fit(x)

plt.plot(x, y_pred)
plt.show()

How do I find the caller of a method using stacktrace or reflection?

Sounds like you're trying to avoid passing a reference to this into the method. Passing this is way better than finding the caller through the current stack trace. Refactoring to a more OO design is even better. You shouldn't need to know the caller. Pass a callback object if necessary.

Android: Use a SWITCH statement with setOnClickListener/onClick for more than 1 button?

And there's yet a third option. In your onCreate() method, find all the button views that you have and save them as class data members. You can then cascade a group of if-else statements to find which is which. It's kind of messy, but it's a must if you don't know the ID of the buttons (which can be complicated if you are generating buttons in java code).

@Override
public void onClick(View v) {
    if (v == m_myCards) {
        Intent intent = new Intent(this, MyCards.class);
        this.startActivity(intent);
    }
    else if (v == m_exit) {
        MyAlertDialog();
    }
    else if (v == m_back) {
        finish();            
    }

Another nice thing about this technique is that it's flexible and quick (no having to parse IDs). The bad thing is that you need to keep the widgets in memory.

Don't know which method is better.

Modifying the "Path to executable" of a windows service

You can't directly edit your path to execute of a service. For that you can use sc command,

SC CONFIG ServiceName binPath= "Path of your file"

Eg:

sc config MongoDB binPath="I:\Programming\MongoDB\MongoDB\bin\mongod.exe --config I:\Programming\MongoDB\MongoDB\bin\mongod.cfg --service"

T-SQL stored procedure that accepts multiple Id values

Erland Sommarskog has maintained the authoritative answer to this question for the last 16 years: Arrays and Lists in SQL Server.

There are at least a dozen ways to pass an array or list to a query; each has their own unique pros and cons.

I really can't recommend enough to read the article to learn about the tradeoffs among all these options.

VBA using ubound on a multidimensional array

ubound(arr, 1) 

and

ubound(arr, 2) 

Code signing is required for product type 'Application' in SDK 'iOS5.1'

One possible solution which works for me:

  1. Search "code sign" in Build settings
  2. Change everything in code signing identity to "iOS developer", which are "Don't code sign" originally.

Bravo!

Visual Studio move project to a different folder

In VS 2015

  1. Unload your project in the solution explorer
  2. Create a new solution
  3. Copy the projects to the new solution's folder
  4. Right click the solution, add existing project.
  5. If you use some framework such as MVC, you may need to add the reference in the reference manager.

I can't find my git.exe file in my Github folder

The git.exe from Github for windows is located in a path like C:\Users\<username>\AppData\Local\GitHub\PortableGit_<numbersandletters>\bin\git.exe1 You have to replace <username> and <numbersandletters> to the actual situation on your system.

In Android Studio you can specify the path to the Git executable at File->Settings...->Version Control->Git->Path to Git executable. Here you have to include the actual executable name. As an example, in my case the actual path is: C:\Users\dennis\AppData\Local\GitHub\PortableGit_69703d1db91577f4c666e767a6ca5ec50a48d243\bin\git.exe

Edit: Last git update has put the git.exe file in cmd\ folder instead of bin\ . so now the actual path will be as suggested in the comment below by al3xAndr3w.

C:\Users\<username>\AppData\Local\GitHub\PortableGit_<numbersandletters>\cmd\git.exe

Angular expression if array contains

Somewhere in your initialisation put this code.

Array.prototype.contains = function contains(obj) {
    for (var i = 0; i < this.length; i++) {
        if (this[i] === obj) {
            return true;
        }
    }
    return false;
};

Then, you can use it this way:

<li ng-class="{approved: selectedForApproval.contains(jobSet)}"></li>

Smooth scrolling when clicking an anchor link

Well, the solution depends on the type of problem, I use the javascript animate method for the button click. and I use codes from bellow links for the navbar

https://css-tricks.com/snippets/jquery/smooth-scrolling/

$(document).ready(function () {
  $(".js--scroll-to-plans").click(function () {
    $("body,html").animate(
      {
        scrollTop: $(".js--section-plans").offset().top,
      },
      1000
    );
    return false;
  });

  $(".js--scroll-to-start").click(function () {
    $("body,html").animate(
      {
        scrollTop: $(".js--section-features").offset().top,
      },
      1000
    );
    return false;
  });

  $('a[href*="#"]')
  // Remove links that don't actually link to anything
  .not('[href="#"]')
  .not('[href="#0"]')
  .click(function(event) {
    // On-page links
    if (
      location.pathname.replace(/^\//, '') == this.pathname.replace(/^\//, '') 
      && 
      location.hostname == this.hostname
    ) {
      // Figure out element to scroll to
      var target = $(this.hash);
      target = target.length ? target : $('[name=' + this.hash.slice(1) + ']');
      // Does a scroll target exist?
      if (target.length) {
        // Only prevent default if animation is actually gonna happen
        event.preventDefault();
        $('html, body').animate({
          scrollTop: target.offset().top
        }, 1000, function() {
          // Callback after animation
          // Must change focus!
          var $target = $(target);
          $target.focus();
          if ($target.is(":focus")) { // Checking if the target was focused
            return false;
          } else {
            $target.attr('tabindex','-1'); // Adding tabindex for elements not focusable
            $target.focus(); // Set focus again
          };
        });
      }
    }
  });
});

Android - set TextView TextStyle programmatically?

Since setTextAppearance(resId) is only available for API 23 and above, use:

TextViewCompat.setTextAppearance(textViewGoesHere, resId)

This method is internally implemented as follows:

public static void setTextAppearance(@NonNull TextView textView, @StyleRes int resId) {
    if (Build.VERSION.SDK_INT >= 23) {
        textView.setTextAppearance(resId);
    } else {
        textView.setTextAppearance(textView.getContext(), resId);
    }
}

Returning unique_ptr from functions

is there some other clause in the language specification that this exploits?

Yes, see 12.8 §34 and §35:

When certain criteria are met, an implementation is allowed to omit the copy/move construction of a class object [...] This elision of copy/move operations, called copy elision, is permitted [...] in a return statement in a function with a class return type, when the expression is the name of a non-volatile automatic object with the same cv-unqualified type as the function return type [...]

When the criteria for elision of a copy operation are met and the object to be copied is designated by an lvalue, overload resolution to select the constructor for the copy is first performed as if the object were designated by an rvalue.


Just wanted to add one more point that returning by value should be the default choice here because a named value in the return statement in the worst case, i.e. without elisions in C++11, C++14 and C++17 is treated as an rvalue. So for example the following function compiles with the -fno-elide-constructors flag

std::unique_ptr<int> get_unique() {
  auto ptr = std::unique_ptr<int>{new int{2}}; // <- 1
  return ptr; // <- 2, moved into the to be returned unique_ptr
}

...

auto int_uptr = get_unique(); // <- 3

With the flag set on compilation there are two moves (1 and 2) happening in this function and then one move later on (3).

Angular 2 - Checking for server errors from subscribe

As stated in the relevant RxJS documentation, the .subscribe() method can take a third argument that is called on completion if there are no errors.

For reference:

  1. [onNext] (Function): Function to invoke for each element in the observable sequence.
  2. [onError] (Function): Function to invoke upon exceptional termination of the observable sequence.
  3. [onCompleted] (Function): Function to invoke upon graceful termination of the observable sequence.

Therefore you can handle your routing logic in the onCompleted callback since it will be called upon graceful termination (which implies that there won't be any errors when it is called).

this.httpService.makeRequest()
    .subscribe(
      result => {
        // Handle result
        console.log(result)
      },
      error => {
        this.errors = error;
      },
      () => {
        // 'onCompleted' callback.
        // No errors, route to new page here
      }
    );

As a side note, there is also a .finally() method which is called on completion regardless of the success/failure of the call. This may be helpful in scenarios where you always want to execute certain logic after an HTTP request regardless of the result (i.e., for logging purposes or for some UI interaction such as showing a modal).

Rx.Observable.prototype.finally(action)

Invokes a specified action after the source observable sequence terminates gracefully or exceptionally.

For instance, here is a basic example:

import { Observable } from 'rxjs/Rx';
import 'rxjs/add/operator/finally';

// ...

this.httpService.getRequest()
    .finally(() => {
      // Execute after graceful or exceptionally termination
      console.log('Handle logging logic...');
    })
    .subscribe (
      result => {
        // Handle result
        console.log(result)
      },
      error => {
        this.errors = error;
      },
      () => {
        // No errors, route to new page
      }
    );

How to run SQL script in MySQL?

use the following from mysql command prompt-

source \\home\\user\\Desktop\\test.sql;

Use no quotation. Even if the path contains space(' ') use no quotation at all.

Schema validation failed with the following errors: Data path ".builders['app-shell']" should have required property 'class'

I have to say, if you don't want to change anything in package.json file, try to update your Node.js version to latest. (currently 12.13.1 LTS)

Add Custom Headers using HttpWebRequest

A simple method of creating the service, adding headers and reading the JSON response,

private static void WebRequest()
{
    const string WEBSERVICE_URL = "<<Web Service URL>>";
    try
    {
        var webRequest = System.Net.WebRequest.Create(WEBSERVICE_URL);
        if (webRequest != null)
        {
            webRequest.Method = "GET";
            webRequest.Timeout = 20000;
            webRequest.ContentType = "application/json";
            webRequest.Headers.Add("Authorization", "Basic dcmGV25hZFzc3VudDM6cGzdCdvQ=");
            using (System.IO.Stream s = webRequest.GetResponse().GetResponseStream())
            {
                using (System.IO.StreamReader sr = new System.IO.StreamReader(s))
                {
                    var jsonResponse = sr.ReadToEnd();
                    Console.WriteLine(String.Format("Response: {0}", jsonResponse));
                }
            }
        }
    }
    catch (Exception ex)
    {
        Console.WriteLine(ex.ToString());
    }
}

Display back button on action bar

This is simple and works for me very well

add this inside onCreate() method

getSupportActionBar().setHomeButtonEnabled(true);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);

add this outside oncreate() method

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    onBackPressed();
    return true;
}

How to delete mysql database through shell command

MySQL has discontinued drop database command from mysql client shell. Need to use mysqladmin to drop a database.

Android Camera Preview Stretched

Just to make this thread more complete i am adding my version of answer:

What i wanted to achieve: The surface view shouldn't be stretched, and it should cover the whole screen, Moreover, there was only a landscape mode in my app.

Solution:

The solution is an extremely small extension to F1sher's solution:

=> First step is to integrate F1sher's solution.

=> Now, there might arise a scenario in F1sher's solution when the surface view doesn't covers the whole screen, The solution is to make the surface view greater than the screen dimensions so that it covers the whole screen, for that:

    size = getOptimalPreviewSize(mCamera.getParameters().getSupportedPreviewSizes(), screenWidth, screenHeight);

    Camera.Parameters parameters = mCamera.getParameters();
    parameters.setPreviewSize(size.width, size.height);


    mCamera.setParameters(parameters);      

    double screenRatio = (double) screenHeight / screenWidth;
    double previewRatio = (double) size.height / size.width;

    if (previewRatio > screenRatio)     /*if preview ratio is greater than screen ratio then we will have to recalculate the surface height while keeping the surface width equal to the screen width*/
    {
        RelativeLayout.LayoutParams params1 = new RelativeLayout.LayoutParams(screenWidth, (int) (screenWidth * previewRatio));
        params1.addRule(RelativeLayout.CENTER_IN_PARENT);
        flPreview.setLayoutParams(params1);

        flPreview.setClipChildren(false);

        LayoutParams surfaceParams = new LayoutParams(screenWidth, (int) (screenWidth * previewRatio));
        surfaceParams.gravity = Gravity.CENTER;
        mPreview.setLayoutParams(surfaceParams);        
    }
    else     /*if preview ratio is smaller than screen ratio then we will have to recalculate the surface width while keeping the surface height equal to the screen height*/
    {
        RelativeLayout.LayoutParams params1 = new RelativeLayout.LayoutParams((int) ((double) screenHeight / previewRatio), screenHeight);
        params1.addRule(RelativeLayout.CENTER_IN_PARENT);
        flPreview.setLayoutParams(params1);
        flPreview.setClipChildren(false);

        LayoutParams surfaceParams = new LayoutParams((int) ((double) screenHeight / previewRatio), screenHeight);
        surfaceParams.gravity = Gravity.CENTER;
        mPreview.setLayoutParams(surfaceParams);

    }       

    flPreview.addView(mPreview); 

  /*  The TopMost layout used is the RelativeLayout, flPreview is the FrameLayout in which Surface View is added, mPreview is an instance of a class which extends SurfaceView  */

What is the recommended way to delete a large number of items from DynamoDB?

The answer of this question depends on the number of items and their size and your budget. Depends on that we have following 3 cases:

1- The number of items and size of items in the table are not very much. then as Steffen Opel said you can Use Query rather than Scan to retrieve all items for user_id and then loop over all returned items and either facilitate DeleteItem or BatchWriteItem. But keep in mind you may burn a lot of throughput capacity here. For example, consider a situation where you need delete 1000 items from a DynamoDB table. Assume that each item is 1 KB in size, resulting in Around 1MB of data. This bulk-deleting task will require a total of 2000 write capacity units for query and delete. To perform this data load within 10 seconds (which is not even considered as fast in some applications), you would need to set the provisioned write throughput of the table to 200 write capacity units. As you can see its doable to use this way if its for less number of items or small size items.

2- We have a lot of items or very large items in the table and we can store them according to the time into different tables. Then as jonathan Said you can just delete the table. this is much better but I don't think it is matched with your case. As you want to delete all of users data no matter what is the time of creation of logs, so in this case you can't delete a particular table. if you wanna have a separate table for each user then I guess if number of users are high then its so expensive and it is not practical for your case.

3- If you have a lot of data and you can't divide your hot and cold data into different tables and you need to do large scale delete frequently then unfortunately DynamoDB is not a good option for you at all. It may become more expensive or very slow(depends on your budget). In these cases I recommend to find another database for your data.

Hibernate Auto Increment ID

Using netbeans New Entity Classes from Database with a mysql auto_increment column, creates you an attribute with the following hibernate.hbm.xml: id is auto increment

Move the mouse pointer to a specific position?

You can't move a mouse but can lock it. Note: that you must call requestPointerLock in click event.

Small Example:

var canvas = document.getElementById('mycanvas');
canvas.requestPointerLock = canvas.requestPointerLock || canvas.mozRequestPointerLock || canvas.webkitRequestPointerLock;
canvas.requestPointerLock();

Documentation and full code example:

https://developer.mozilla.org/en-US/docs/Web/API/Pointer_Lock_API

SELECT max(x) is returning null; how can I make it return 0?

Oracle would be

SELECT NVL(MAX(X), 0) AS MaxX
FROM tbl
WHERE XID = 1;

Setting environment variables in Linux using Bash

export VAR=value will set VAR to value. Enclose it in single quotes if you want spaces, like export VAR='my val'. If you want the variable to be interpolated, use double quotes, like export VAR="$MY_OTHER_VAR".

Swift Error: Editor placeholder in source file

Go to Product > Clean Build Folder

Spring MVC + JSON = 406 Not Acceptable

Maybe all fields of your POJO need Getter and Setter.

I fixed it according to this issue. reference:Spring MVC - HttpMediaTypeNotAcceptableException

And 406 is not a useful message to fix the bug. You should debug into the codes and see what the Exception is on earth.

Parsing huge logfiles in Node.js - read in line-by-line

I have made a node module to read large file asynchronously text or JSON. Tested on large files.

var fs = require('fs')
, util = require('util')
, stream = require('stream')
, es = require('event-stream');

module.exports = FileReader;

function FileReader(){

}

FileReader.prototype.read = function(pathToFile, callback){
    var returnTxt = '';
    var s = fs.createReadStream(pathToFile)
    .pipe(es.split())
    .pipe(es.mapSync(function(line){

        // pause the readstream
        s.pause();

        //console.log('reading line: '+line);
        returnTxt += line;        

        // resume the readstream, possibly from a callback
        s.resume();
    })
    .on('error', function(){
        console.log('Error while reading file.');
    })
    .on('end', function(){
        console.log('Read entire file.');
        callback(returnTxt);
    })
);
};

FileReader.prototype.readJSON = function(pathToFile, callback){
    try{
        this.read(pathToFile, function(txt){callback(JSON.parse(txt));});
    }
    catch(err){
        throw new Error('json file is not valid! '+err.stack);
    }
};

Just save the file as file-reader.js, and use it like this:

var FileReader = require('./file-reader');
var fileReader = new FileReader();
fileReader.readJSON(__dirname + '/largeFile.json', function(jsonObj){/*callback logic here*/});

Best practices when running Node.js with port 80 (Ubuntu / Linode)

For port 80 (which was the original question), Daniel is exactly right. I recently moved to https and had to switch from iptables to a light nginx proxy managing the SSL certs. I found a useful answer along with a gist by gabrielhpugliese on how to handle that. Basically I

Hopefully that can save someone else some headaches. I'm sure there's a pure-node way of doing this, but nginx was quick and it worked.

How do I use a regex in a shell script?

the problem is you're trying to use regex features not supported by grep. namely, your \d won't work. use this instead:

REGEX_DATE="^[[:digit:]]{2}[-/][[:digit:]]{2}[-/][[:digit:]]{4}$"
echo "$1" | grep -qE "${REGEX_DATE}"
echo $?

you need the -E flag to get ERE in order to use {#} style.

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

It means you are trying to implement a non-existing interface or you're extending an non-existing class.

Try to refresh your Eclipse.

If it doesn't work, it may mean that you have a reference to a JAR that is not in the build path. Check your project's classpath and verify that the jar containing the interface or the class is in it.

JPA - Returning an auto generated id after persist()

The ID is only guaranteed to be generated at flush time. Persisting an entity only makes it "attached" to the persistence context. So, either flush the entity manager explicitely:

em.persist(abc);
em.flush();
return abc.getId();

or return the entity itself rather than its ID. When the transaction ends, the flush will happen, and users of the entity outside of the transaction will thus see the generated ID in the entity.

@Override
public ABC addNewABC(ABC abc) {
    abcDao.insertABC(abc);
    return abc;
}

Angular2 multiple router-outlet in the same template

You can have multiple router-outlet in same template by configuring your router and providing name to your router-outlet, you can achieve this as follows.

Advantage of below approach is thats you can avoid dirty looking URL with it. eg: /home(aux:login) etc.

Assuming on load you are bootstraping appComponent.

app.component.html

<div class="layout">
    <div class="page-header">
        //first outlet to load required component
        <router-outlet name='child1'></router-outlet>
    </div>
    <div class="content">
        //second outlet to load required component
        <router-outlet name='child2'></router-outlet>
    </div>
</div>

Add following to your router.

{
    path: 'home',  // you can keep it empty if you do not want /home
    component: 'appComponent',
    children: [
        {
            path: '',
            component: childOneComponent,
            outlet: 'child1'
        },
        {
            path: '',
            component: childTwoComponent,
            outlet: 'child2'
        }
    ]
}

Now when /home is loaded appComponent will get load with allocated template, then angular router will check the route and load the children component in specified router outlet on the basis of name.

Like above you can configure your router to have multiple router-outlet in same route.

How to send JSON instead of a query string with $.ajax?

If you are sending this back to asp.net and need the data in request.form[] then you'll need to set the content type to "application/x-www-form-urlencoded; charset=utf-8"

Original post here

Secondly get rid of the Datatype, if your not expecting a return the POST will wait for about 4 minutes before failing. See here

Using DISTINCT and COUNT together in a MySQL Query

SELECTING DISTINCT PRODUCT AND DISPLAY COUNT PER PRODUCT

for another answer about this type of question this is my another answer for getting count of product base on product name distinct like this sample below:

Table Value

select * FROM Product

Counted Product Name

SELECT DISTINCT(Product_Name),
(SELECT COUNT(Product_Name) 
from Product  WHERE Product_Name = Prod.Product_Name)  
as `Product_Count`
from Product as Prod

Record Count: 4; Execution Time: 2ms

Regex for remove everything after | (with | )

In a .txt file opened with Notepad++,
press Ctrl-F
go in the tab "Replace"
write the regex pattern \|.+ in the space Find what
and let the space Replace with blank

Then tick the choice matches newlines after the choice Regular expression
and press two times on the Replace button

Can I append an array to 'formdata' in javascript?

var formData = new FormData; var arr = ['item1', 'item2', 'item3'];

arr.forEach(item => {
    formData.append(
        "myFile",item
    ); });

Execute stored procedure with an Output parameter?

From http://support.microsoft.com/kb/262499

Example:

CREATE PROCEDURE Myproc

@parm varchar(10),
**@parm1OUT varchar(30) OUTPUT**,
**@parm2OUT varchar(30) OUTPUT**
AS
  SELECT @parm1OUT='parm 1' + @parm
 SELECT @parm2OUT='parm 2' + @parm

GO

DECLARE @SQLString NVARCHAR(500)
DECLARE @ParmDefinition NVARCHAR(500)
DECLARE @parmIN VARCHAR(10)
DECLARE @parmRET1 VARCHAR(30)
DECLARE @parmRET2 VARCHAR(30)

SET @parmIN=' returned'
SET @SQLString=N'EXEC Myproc @parm,
                         @parm1OUT OUTPUT, @parm2OUT OUTPUT'
SET @ParmDefinition=N'@parm varchar(10),
                  @parm1OUT varchar(30) OUTPUT,
                  @parm2OUT varchar(30) OUTPUT'

EXECUTE sp_executesql
@SQLString,
@ParmDefinition,
@parm=@parmIN,
@parm1OUT=@parmRET1 OUTPUT,@parm2OUT=@parmRET2 OUTPUT

SELECT @parmRET1 AS "parameter 1", @parmRET2 AS "parameter 2"
GO
DROP PROCEDURE Myproc

Hope this helps!

Need a good hex editor for Linux

I am a VIMer. I can do some rare Hex edits with:

  • :%!xxd to switch into hex mode

  • :%!xxd -r to exit from hex mode

But I strongly recommend ht

apt-cache show ht

Package: ht
Version: 2.0.18-1
Installed-Size: 1780
Maintainer: Alexander Reichle-Schmehl <[email protected]>

Homepage: http://hte.sourceforge.net/

Note: The package is called ht, whereas the executable is named hte after the package was installed.

  1. Supported file formats
    • common object file format (COFF/XCOFF32)
    • executable and linkable format (ELF)
    • linear executables (LE)
    • standard DO$ executables (MZ)
    • new executables (NE)
    • portable executables (PE32/PE64)
    • java class files (CLASS)
    • Mach exe/link format (MachO)
    • X-Box executable (XBE)
    • Flat (FLT)
    • PowerPC executable format (PEF)
  2. Code & Data Analyser
    • finds branch sources and destinations recursively
    • finds procedure entries
    • creates labels based on this information
    • creates xref information
    • allows to interactively analyse unexplored code
    • allows to create/rename/delete labels
    • allows to create/edit comments
    • supports x86, ia64, alpha, ppc and java code
  3. Target systems
    • DJGPP
    • GNU/Linux
    • FreeBSD
    • OpenBSD
    • Win32

How to update Ruby Version 2.0.0 to the latest version in Mac OSX Yosemite?

Fast way to upgrade ruby to v2.4+

brew upgrade ruby

or

sudo gem update --system 

Set up DNS based URL forwarding in Amazon Route53

If you're still having issues with the simple approach, creating an empty bucket then Redirect all requests to another host name under Static web hosting in properties via the console. Ensure that you have set 2 A records in route53, one for final-destination.com and one for redirect-to.final-destination.com. The settings for each of these will be identical, but the name will be different so it matches the names that you set for your buckets / URLs.

Search an Oracle database for tables with specific column names?

The data you want is in the "cols" meta-data table:

SELECT * FROM COLS WHERE COLUMN_NAME = 'id'

This one will give you a list of tables that have all of the columns you want:

select distinct
  C1.TABLE_NAME
from
  cols c1
  inner join
  cols c2
  on C1.TABLE_NAME = C2.TABLE_NAME
  inner join
  cols c3
  on C2.TABLE_NAME = C3.TABLE_NAME
  inner join
  cols c4
  on C3.TABLE_NAME = C4.TABLE_NAME  
  inner join
  tab t
  on T.TNAME = C1.TABLE_NAME
where T.TABTYPE = 'TABLE' --could be 'VIEW' if you wanted
  and upper(C1.COLUMN_NAME) like upper('%id%')
  and upper(C2.COLUMN_NAME) like upper('%fname%')
  and upper(C3.COLUMN_NAME) like upper('%lname%')
  and upper(C4.COLUMN_NAME) like upper('%address%')  

To do this in a different schema, just specify the schema in front of the table, as in

SELECT * FROM SCHEMA1.COLS WHERE COLUMN_NAME LIKE '%ID%';

If you want to combine the searches of many schemas into one output result, then you could do this:

SELECT DISTINCT
  'SCHEMA1' AS SCHEMA_NAME
 ,TABLE_NAME
FROM SCHEMA1.COLS
WHERE COLUMN_NAME LIKE '%ID%'
UNION
SELECT DISTINCT
  'SCHEMA2' AS SCHEMA_NAME
 ,TABLE_NAME
FROM SCHEMA2.COLS
WHERE COLUMN_NAME LIKE '%ID%'

How to add empty spaces into MD markdown readme on GitHub?

You can use <pre> to display all spaces & blanks you have typed. E.g.:

<pre>
hello, this is
   just an     example
....
</pre>

How to truncate text in Angular2?

You can truncate text based on CSS. It helps to truncate a text-based on width not fix character.

Example

CSS

.truncate {
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;
        }

.content {
            width:100%;
            white-space: nowrap;
            overflow: hidden;
            text-overflow: ellipsis;
        }

HTML

<div class="content">
    <span class="truncate">Lorem Ipsum is simply dummied text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</span>
</div>

Note: this code use full for one line not for more than one.

Ketan's Solution is best if you want to do it by Angular

What is the correct way to create a single-instance WPF application?

Please check the proposed solution from here that uses a semaphore to determine if an existing instance is already running, works for a WPF application and can pass arguments from second instance to the first already running instance by using a TcpListener and a TcpClient:

It works also for .NET Core, not only for .NET Framework.

Android: how to handle button click

Question#1 - These are the only way to handle view clicks.

Question#2 -
Option#1/Option#4 - There's not much difference between option#1 and option#4. The only difference I see is in one case activity is implementing the OnClickListener, whereas, in the other case, there'd be an anonymous implementation.

Option#2 - In this method an anonymous class will be generated. This method is a bit cumborsome, as, you'd need to do it multiple times, if you have multiple buttons. For Anonymous classes, you have to be careful for handling memory leaks.

Option#3 - Though, this is a easy way. Usually, Programmers try not to use any method until they write it, and hence this method is not widely used. You'd see mostly people use Option#4. Because it is cleaner in term of code.

Can not change UILabel text color

It is possible, they are not connected in InterfaceBuilder.

Text colour(colorWithRed:(188/255) green:(149/255) blue:(88/255)) is correct, may be mistake in connections,

backgroundcolor is used for the background colour of label and textcolor is used for property textcolor.

How to cast Object to boolean?

If the object is actually a Boolean instance, then just cast it:

boolean di = (Boolean) someObject;

The explicit cast will do the conversion to Boolean, and then there's the auto-unboxing to the primitive value. Or you can do that explicitly:

boolean di = ((Boolean) someObject).booleanValue();

If someObject doesn't refer to a Boolean value though, what do you want the code to do?

Ruby on Rails: How do I add placeholder text to a f.text_field?

With rails >= 3.0, you can simply use the placeholder option.

f.text_field :attr, placeholder: "placeholder text"

How can I extract substrings from a string in Perl?

You could do something like this:

my $data = <<END;
1) Scheme ID: abc-456-hu5t10 (High priority) *
2) Scheme ID: frt-78f-hj542w (Balanced)
3) Scheme ID: 23f-f974-nm54w (super formula run) *
END

foreach (split(/\n/,$data)) {
  $_ =~ /Scheme ID: ([a-z0-9-]+)\s+\(([^)]+)\)\s*(\*)?/ || next;
  my ($id,$word,$star) = ($1,$2,$3);
  print "$id $word $star\n";
}

The key thing is the Regular expression:

Scheme ID: ([a-z0-9-]+)\s+\(([^)]+)\)\s*(\*)?

Which breaks up as follows.

The fixed String "Scheme ID: ":

Scheme ID: 

Followed by one or more of the characters a-z, 0-9 or -. We use the brackets to capture it as $1:

([a-z0-9-]+)

Followed by one or more whitespace characters:

\s+

Followed by an opening bracket (which we escape) followed by any number of characters which aren't a close bracket, and then a closing bracket (escaped). We use unescaped brackets to capture the words as $2:

\(([^)]+)\)

Followed by some spaces any maybe a *, captured as $3:

\s*(\*)?

Java - Writing strings to a CSV file

    String filepath="/tmp/employee.csv";
    FileWriter sw = new FileWriter(new File(filepath));
    CSVWriter writer = new CSVWriter(sw);
    writer.writeAll(allRows);

    String[] header= new String[]{"ErrorMessage"};
    writer.writeNext(header);

    List<String[]> errorData = new ArrayList<String[]>();
    for(int i=0;i<1;i++){
        String[] data = new String[]{"ErrorMessage"+i};
        errorData.add(data);
    }
    writer.writeAll(errorData);

    writer.close();

How can I switch to another branch in git?

[git checkout "branch_name"]

is another way to say:

[git checkout -b branch_name origin/branch_name]

in case "branch_name" exists only remotely.

[git checkout -b branch_name origin/branch_name] is useful in case you have multiple remotes.

Regarding [git checkout origin 'another_branch'] I'm not sure this is possible, AFAK you can do this using "fetch" command -- [git fetch origin 'another_branch']

git am error: "patch does not apply"

This kind of error can be caused by LF vs CRLF line ending mismatches, e.g. when you're looking at the patch file and you're absolutely sure it should be able to apply, but it just won't.

To test this out, if you have a patch that applies to just one file, you can try running 'unix2dos' or 'dos2unix' on just that file (try both, to see which one causes the file to change; you can get these utilities for Windows as well as Unix), then commit that change as a test commit, then try applying the patch again. If that works, that was the problem.

NB git am applies patches as LF by default (even if the patch file contains CRLF), so if you want to apply CRLF patches to CRLF files you must use git am --keep-cr, as per this answer.

Using arrays or std::vectors in C++, what's the performance gap?

If you compile the software in debug mode, many compilers will not inline the accessor functions of the vector. This will make the stl vector implementation much slower in circumstances where performance is an issue. It will also make the code easier to debug since you can see in the debugger how much memory was allocated.

In optimized mode, I would expect the stl vector to approach the efficiency of an array. This is since many of the vector methods are now inlined.

Java compiler level does not match the version of the installed Java project facet

You can change project facet from Project --> Properties --> Project Facet --> Java --> {required JDK version}

Using .htaccess to make all .html pages to run as .php files?

In My Godaddy Server the following code worked

Options +ExecCGI
AddType application/x-httpd-php .php .html
AddHandler x-httpd-php5 .php .html

JavaScript: SyntaxError: missing ) after argument list

just posting in case anyone else has the same error...

I was using 'await' outside of an 'async' function and for whatever reason that results in a 'missing ) after argument list' error.

The solution was to make the function asynchronous

function functionName(args) {}

becomes

async function functionName(args) {}

Unicode character in PHP string

Try Portable UTF-8:

$str = utf8_chr( 0x1000 );
$str = utf8_chr( '\u1000' );
$str = utf8_chr( 4096 );

All work exactly the same way. You can get the codepoint of a character with utf8_ord(). Read more about Portable UTF-8.

How to delay the .keyup() handler until the user stops typing?

Take a look at the autocomplete plugin. I know that it allows you to specify a delay or a minimum number of characters. Even if you don't end up using the plugin, looking through the code will give you some ideas on how to implement it yourself.

req.query and req.param in ExpressJS

I would suggest using following

req.param('<param_name>')

req.param("") works as following

Lookup is performed in the following order:

req.params
req.body
req.query

Direct access to req.body, req.params, and req.query should be favoured for clarity - unless you truly accept input from each object.

Ref:http://expressjs.com/4x/api.html#req.param

Padding is invalid and cannot be removed?

My issue was that the encrypt's passPhrase didn't match the decrypt's passPhrase... so it threw this error .. a little misleading.

JSON encode MySQL results

$rows = json_decode($mysql_result,true);

as simple as that :-)

C: convert double to float, preserving decimal point precision

float and double don't store decimal places. They store binary places: float is (assuming IEEE 754) 24 significant bits (7.22 decimal digits) and double is 53 significant bits (15.95 significant digits).

Converting from double to float will give you the closest possible float, so rounding won't help you. Goining the other way may give you "noise" digits in the decimal representation.

#include <stdio.h>

int main(void) {
    double orig = 12345.67;
    float f = (float) orig;
    printf("%.17g\n", f); // prints 12345.669921875
    return 0;
}

To get a double approximation to the nice decimal value you intended, you can write something like:

double round_to_decimal(float f) {
    char buf[42];
    sprintf(buf, "%.7g", f); // round to 7 decimal digits
    return atof(buf);
}

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

Simplifying @matt's answer -

git blame -L14,15 -- <file_path>

Here you will get a blame for a lines 14 to 15.

Since -L option expects Range as a param we can't get a Blame for a single line using the -L option`.

Reference

How can I compare a date and a datetime in Python?

I am trying to compare date which are in string format like '20110930'

benchMark = datetime.datetime.strptime('20110701', "%Y%m%d") 

actualDate = datetime.datetime.strptime('20110930', "%Y%m%d")

if actualDate.date() < benchMark.date():
    print True

Merge/flatten an array of arrays

To flatten a two-dimensional array in one line:

[[1, 2], [3, 4, 5]].reduce(Function.prototype.apply.bind(Array.prototype.concat))
// => [ 1, 2, 3, 4, 5 ]

Redirect parent window from an iframe action

For current page - window.location.href = "Your url here";

For Parent page - window.top.location.href = "Your url here";

From HTML

<a href="http://someurl" target="_top">link</a>

How to change the background color of the options menu?

For Android 2.3 this can be done with some very heavy hacking:

The root cause for the issues with Android 2.3 is that in LayoutInflater the mConstructorArgs[0] = mContext is only set during running calls to

http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/2.3.3_r1/android/view/LayoutInflater.java/#352

protected void setMenuBackground(){

    getLayoutInflater().setFactory( new Factory() {

        @Override
        public View onCreateView (final String name, final Context context, final AttributeSet attrs ) {

            if ( name.equalsIgnoreCase( "com.android.internal.view.menu.IconMenuItemView" ) ) {

                try { // Ask our inflater to create the view
                    final LayoutInflater f = getLayoutInflater();
                    final View[] view = new View[1]:
                    try {
                        view[0] = f.createView( name, null, attrs );
                    } catch (InflateException e) {
                        hackAndroid23(name, attrs, f, view);
                    }
                    // Kind of apply our own background
                    new Handler().post( new Runnable() {
                        public void run () {
                            view.setBackgroundResource( R.drawable.gray_gradient_background);
                        }
                    } );
                    return view;
                }
                catch ( InflateException e ) {
                }
                catch ( ClassNotFoundException e ) {
                }
            }
            return null;
        }
    });
}

static void hackAndroid23(final String name,
    final android.util.AttributeSet attrs, final LayoutInflater f,
    final TextView[] view) {
    // mConstructorArgs[0] is only non-null during a running call to inflate()
    // so we make a call to inflate() and inside that call our dully XmlPullParser get's called
    // and inside that it will work to call "f.createView( name, null, attrs );"!
    try {
        f.inflate(new XmlPullParser() {
            @Override
            public int next() throws XmlPullParserException, IOException {
                try {
                    view[0] = (TextView) f.createView( name, null, attrs );
                } catch (InflateException e) {
                } catch (ClassNotFoundException e) {
                }
                throw new XmlPullParserException("exit");
            }   
        }, null, false);
    } catch (InflateException e1) {
        // "exit" ignored
    }
}

I tested it to work on Android 2.3 and to still work on earlier versions. If anything breaks again in later Android versions you'll simply see the default menu-style instead

Excel date to Unix timestamp

You're apparently off by one day, exactly 86400 seconds. Use the number 2209161600 Not the number 2209075200 If you Google the two numbers, you'll find support for the above. I tried your formula but was always coming up 1 day different from my server. It's not obvious from the unix timestamp unless you think in unix instead of human time ;-) but if you double check then you'll see this might be correct.

PostgreSQL Exception Handling

To catch the error message and its code:

do $$       
begin

    create table yyy(a int);
    create table yyy(a int); -- this will cause an error

exception when others then 

    raise notice 'The transaction is in an uncommittable state. '
                 'Transaction was rolled back';

    raise notice '% %', SQLERRM, SQLSTATE;

end; $$ 
language 'plpgsql';

Haven't found the line number yet

UPDATE April, 16, 2019

As suggested by Diego Scaravaggi, for Postgres 9.2 and up, use GET STACKED DIAGNOSTICS:

do language plpgsql $$
declare
    v_state   TEXT;
    v_msg     TEXT;
    v_detail  TEXT;
    v_hint    TEXT;
    v_context TEXT;
begin

    create table yyy(a int);
    create table yyy(a int); -- this will cause an error

exception when others then 

    get stacked diagnostics
        v_state   = returned_sqlstate,
        v_msg     = message_text,
        v_detail  = pg_exception_detail,
        v_hint    = pg_exception_hint,
        v_context = pg_exception_context;

    raise notice E'Got exception:
        state  : %
        message: %
        detail : %
        hint   : %
        context: %', v_state, v_msg, v_detail, v_hint, v_context;

    raise notice E'Got exception:
        SQLSTATE: % 
        SQLERRM: %', SQLSTATE, SQLERRM;     

    raise notice '%', message_text; -- invalid. message_text is contextual to GET STACKED DIAGNOSTICS only

end; $$;

Result:

NOTICE:  Got exception:
        state  : 42P07
        message: relation "yyy" already exists
        detail : 
        hint   : 
        context: SQL statement "create table yyy(a int)"
PL/pgSQL function inline_code_block line 11 at SQL statement
NOTICE:  Got exception:
        SQLSTATE: 42P07 
        SQLERRM: relation "yyy" already exists

ERROR:  column "message_text" does not exist
LINE 1: SELECT message_text
               ^
QUERY:  SELECT message_text
CONTEXT:  PL/pgSQL function inline_code_block line 33 at RAISE
SQL state: 42703

Aside from GET STACKED DIAGNOSTICS is SQL standard-compliant, its diagnostics variables (e.g., message_text) are contextual to GSD only. So if you have a field named message_text in your table, there's no chance that GSD can interfere with your field's value.

Still no line number though.

Why can't I use background image and color together?

To tint an image, you can use CSS3 background to stack images and a linear-gradient. In the example below, I use a linear-gradient with no actual gradient. The browser treats gradients as images (I think it actually generates a bitmap and overlays it) and thus, is actually stacking multiple images.

background: linear-gradient(0deg, rgba(2,173,231,0.5), rgba(2,173,231,0.5)), url(images/mba-grid-5px-bg.png) repeat;

Will yield a graph-paper with light blue tint, if you had the png. Note that the stacking order might work in reverse to your mental model, with the first item being on top.

Excellent documentation by Mozilla, here:

https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Using_multiple_backgrounds

Tool for building the gradients:

http://www.colorzilla.com/gradient-editor/

Note - doesn't work in IE11! I'll post an update when I find out why, since its supposed to.

How to implement infinity in Java?

For the numeric wrapper types.

e.g Double.POSITVE_INFINITY

Hope this might help you.

How to upgrade all Python packages with pip

import os
import pip
from subprocess import call, check_call

pip_check_list = ['pip', 'pip3']
pip_list = []
FNULL = open(os.devnull, 'w')


for s_pip in pip_check_list:
    try:
        check_call([s_pip, '-h'], stdout=FNULL)
        pip_list.append(s_pip)
    except FileNotFoundError:
        pass


for dist in pip.get_installed_distributions():
    for pip in pip_list:
        call("{0} install --upgrade ".format(pip) + dist.project_name, shell=True)

I took Ramana's answer and made it pip3 friendly.

Remove all unused resources from an android project

Attention Android Wear developers: "Remove Unused Resources" will delete the xml file where you declare the capability name (res/values/wear.xml) and the phone won't be able to connect to the watch. I spent hours trying to figure out this bug in my app.

How does C#'s random number generator work?

You can use Random.Next(int maxValue):

Return: A 32-bit signed integer greater than or equal to zero, and less than maxValue; that is, the range of return values ordinarily includes zero but not maxValue. However, if maxValue equals zero, maxValue is returned.

var r = new Random();
// print random integer >= 0 and  < 100
Console.WriteLine(r.Next(100));

For this case however you could use Random.Next(int minValue, int maxValue), like this:

// print random integer >= 1 and < 101
Console.WriteLine(r.Next(1, 101);)
// or perhaps (if you have this specific case)
Console.WriteLine(r.Next(100) + 1);

java.lang.ClassNotFoundException: oracle.jdbc.driver.OracleDriver

I was getting same kinda error but after copying the ojdbc14.jar into lib folder, no more exception.(copy ojdbc14.jar from somewhere and paste it into lib folder inside WebContent.)

Getting A File's Mime Type In Java

if you work on linux OS ,there is a command line file --mimetype:

String mimetype(file){

   //1. run cmd
   Object cmd=Runtime.getRuntime().exec("file --mime-type "+file);

   //2 get output of cmd , then 
    //3. parse mimetype
    if(output){return output.split(":")[1].trim(); }
    return "";
}

Then

mimetype("/home/nyapp.war") //  'application/zip'

mimetype("/var/www/ggg/au.mp3") //  'audio/mp3'

Could not locate Gemfile

Make sure you are in the project directory before running bundle install. For example, after running rails new myproject, you will want to cd myproject before running bundle install.

How does one capture a Mac's command key via JavaScript?

For people using jQuery, there is an excellent plugin for handling key events:

jQuery hotkeys on GitHub

For capturing ?+S and Ctrl+S I'm using this:

$(window).bind('keydown.ctrl_s keydown.meta_s', function(event) {
    event.preventDefault();
    // Do something here
});

What is the "N+1 selects problem" in ORM (Object-Relational Mapping)?

Suppose you have COMPANY and EMPLOYEE. COMPANY has many EMPLOYEES (i.e. EMPLOYEE has a field COMPANY_ID).

In some O/R configurations, when you have a mapped Company object and go to access its Employee objects, the O/R tool will do one select for every employee, wheras if you were just doing things in straight SQL, you could select * from employees where company_id = XX. Thus N (# of employees) plus 1 (company)

This is how the initial versions of EJB Entity Beans worked. I believe things like Hibernate have done away with this, but I'm not too sure. Most tools usually include info as to their strategy for mapping.

PHP Warning: PHP Startup: Unable to load dynamic library

In my case, this message started to appear when I updated the php version to 7.4.

To solve it I had to look for the php.ini files found inside the php version folder (/etc/php/7.4/apache2/ && /etc/php/7.4/cli/) checking the lines where the extensions I could see that the extensions gd2 and intl were uncommented.

Change header background color of modal of twitter bootstrap

So, I tried these other ways, but there was a VERY slight irritant and that was if you keep the modal-content border radius, in FF and Chrome, there is a slight bit of white trim showing along the borders, even if you use 5px on the modal-header border radius. (standard modal-content border radius is 6px, so 5px on the modal-header border top radius covers some white).

My solution:

.modal-body
{
    background-color: #FFFFFF;
}

.modal-content
{
    border-radius: 6px;
    -webkit-border-radius: 6px;
    -moz-border-radius: 6px;
    background-color: transparent;
}

.modal-footer
{
    border-bottom-left-radius: 6px;
    border-bottom-right-radius: 6px;
    -webkit-border-bottom-left-radius: 6px;
    -webkit-border-bottom-right-radius: 6px;
    -moz-border-radius-bottomleft: 6px;
    -moz-border-radius-bottomright: 6px;
}

.modal-header
{
    border-top-left-radius: 6px;
    border-top-right-radius: 6px;
    -webkit-border-top-left-radius: 6px;
    -webkit-border-top-right-radius: 6px;
    -moz-border-radius-topleft: 6px;
    -moz-border-radius-topright: 6px;
}

!! CAVEAT !!

You must then set the background colors of the modal-header, modal-content, and modal-footer. This is not bad trade-off, because it allows you to do this:

<div class="modal-header bg-primary">

<div class="modal-body bgColorWhite">

<div class="modal-footer bg-info">

EDIT

Or even better:

<div class="modal-header alert-primary">

Get the last insert id with doctrine 2?

More simple: SELECT max(id) FROM client

Can't push to GitHub because of large file which I already deleted

I am adding to the first answer.

git filter-branch --index-filter 'git rm -r --cached --ignore-unmatch ' HEAD

There will be some merge conflict from origin/master.

Your branch and 'origin/master' have diverged, and have 114 and 109 different commits each, respectively. (use "git pull" to merge the remote branch into yours)

Please run this

git reset --hard origin/master

It will throw away all my staged and unstaged changes, forget everything on my current local branch and make it exactly the same as origin/master.

How to round to 2 decimals with Python?

Most answers suggested round or format. round sometimes rounds up, and in my case I needed the value of my variable to be rounded down and not just displayed as such.

round(2.357, 2)  # -> 2.36

I found the answer here: How do I round a floating point number up to a certain decimal place?

import math
v = 2.357
print(math.ceil(v*100)/100)  # -> 2.36
print(math.floor(v*100)/100)  # -> 2.35

or:

from math import floor, ceil

def roundDown(n, d=8):
    d = int('1' + ('0' * d))
    return floor(n * d) / d

def roundUp(n, d=8):
    d = int('1' + ('0' * d))
    return ceil(n * d) / d

How does one set up the Visual Studio Code compiler/debugger to GCC?

Just wanted to add that if you want to debug stuff, you should compile with debug information before you debug, otherwise the debugger won't work. So, in g++ you need to do g++ -g source.cpp. The -g flag means that the compiler will insert debugging information into your executable, so that you can run gdb on it.

Toolbar navigation icon never set

In case you don't wish to set the toolbar as the action bar, you can use this:

        val toggle = ActionBarDrawerToggle(this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close)
        toggle.isDrawerSlideAnimationEnabled = false
        toggle.isDrawerIndicatorEnabled = false
        toggle.setHomeAsUpIndicator(AppCompatResources.getDrawable(this, ...))
        drawer!!.addDrawerListener(toggle)
        toggle.setToolbarNavigationClickListener {
            setDrawerOpened(!isDrawerOpened())
        }
        toggle.syncState()

fun setDrawerOpened(open: Boolean) {
    if (open == drawerLayout.isDrawerOpen(GravityCompat.START))
        return
    if (open)
        drawerLayout.openDrawer(GravityCompat.START)
    else drawerLayout.closeDrawer(GravityCompat.START)
}

How to start debug mode from command prompt for apache tomcat server?

On windows
$ catalina.bat jpda start
On Linux/Unix
$ catalina.sh jpda start

More info ----> https://cwiki.apache.org/confluence/display/TOMCAT/Developing

How do I programmatically change file permissions?

Apache ant chmod (not very elegant, adding it for completeness) credit shared with @msorsky

    Chmod chmod = new Chmod();
    chmod.setProject(new Project());
    FileSet mySet = new FileSet();
    mySet.setDir(new File("/my/path"));
    mySet.setIncludes("**");
    chmod.addFileset(mySet);
    chmod.setPerm("+w");
    chmod.setType(new FileDirBoth());
    chmod.execute();

Radio Buttons ng-checked with ng-model

Please explain why same ng-model is used? And what value is passed through ng- model and how it is passed? To be more specific, if I use console.log(color) what would be the output?

warning: control reaches end of non-void function [-Wreturn-type]

You just need to return from the main function at some point. The error message says that the function is defined to return a value but you are not returning anything.

  /* .... */
  if (Date1 == Date2)  
     fprintf (stderr , "Indicating that the first date is equal to second date.\n"); 

  return 0;
}

Combining COUNT IF AND VLOOK UP EXCEL

This is trivial when you use SUMPRODUCT. Por ejemplo:

=SUMPRODUCT((worksheet2!A:A=A3)*1)

You could put the above formula in cell B3, where A3 is the name you want to find in worksheet2.

React.js: How to append a component on click?

As @Alex McMillan mentioned, use state to dictate what should be rendered in the dom.

In the example below I have an input field and I want to add a second one when the user clicks the button, the onClick event handler calls handleAddSecondInput( ) which changes inputLinkClicked to true. I am using a ternary operator to check for the truthy state, which renders the second input field

class HealthConditions extends React.Component {
  constructor(props) {
    super(props);


    this.state = {
      inputLinkClicked: false
    }
  }

  handleAddSecondInput() {
    this.setState({
      inputLinkClicked: true
    })
  }


  render() {
    return(
      <main id="wrapper" className="" data-reset-cookie-tab>
        <div id="content" role="main">
          <div className="inner-block">

            <H1Heading title="Tell us about any disabilities, illnesses or ongoing conditions"/>

            <InputField label="Name of condition"
              InputType="text"
              InputId="id-condition"
              InputName="condition"
            />

            {
              this.state.inputLinkClicked?

              <InputField label=""
                InputType="text"
                InputId="id-condition2"
                InputName="condition2"
              />

              :

              <div></div>
            }

            <button
              type="button"
              className="make-button-link"
              data-add-button=""
              href="#"
              onClick={this.handleAddSecondInput}
            >
              Add a condition
            </button>

            <FormButton buttonLabel="Next"
              handleSubmit={this.handleSubmit}
              linkto={
                this.state.illnessOrDisability === 'true' ?
                "/404"
                :
                "/add-your-details"
              }
            />

            <BackLink backLink="/add-your-details" />

          </div>
         </div>
      </main>
    );
  }
}

<strong> vs. font-weight:bold & <em> vs. font-style:italic

<strong> and <em> - unlike <b> and <i> - have clear purpose for web browsers for the blind.

A blind person doesn't browse the web visually, but by sound such as text readers. <strong> and <em>, in addition to encouraging something to be bold or italic, also convey loudness or stressing syllables respectively (OH MY! & Ooooooh Myyyyyyy!). Audio-only browsers are unpredictable when it comes to <b> and <i>... they may make them loud or stress them or they may not... you never can be sure unless you use <strong> and <em>.

How to set a value for a selectize.js input?

First load select dropdown and then selectize it. It will work with normal $(select).val().

How to retrieve available RAM from Windows command line?

Just in case you need this functionality in a Java program, you might want to look at the sigar API: http://www.hyperic.com/products/sigar

Actually, this is no answer to the question, I know, but a hint so you don't have to reinvent the wheel.

How can I pause setInterval() functions?

My simple way:

function Timer (callback, delay) {
  let callbackStartTime
  let remaining = 0

  this.timerId = null
  this.paused = false

  this.pause = () => {
    this.clear()
    remaining -= Date.now() - callbackStartTime
    this.paused = true
  }
  this.resume = () => {
    window.setTimeout(this.setTimeout.bind(this), remaining)
    this.paused = false
  }
  this.setTimeout = () => {
    this.clear()
    this.timerId = window.setInterval(() => {
      callbackStartTime = Date.now()
      callback()
    }, delay)
  }
  this.clear = () => {
    window.clearInterval(this.timerId)
  }

  this.setTimeout()
}

How to use:

_x000D_
_x000D_
let seconds = 0_x000D_
const timer = new Timer(() => {_x000D_
  seconds++_x000D_
  _x000D_
  console.log('seconds', seconds)_x000D_
_x000D_
  if (seconds === 8) {_x000D_
    timer.clear()_x000D_
_x000D_
    alert('Game over!')_x000D_
  }_x000D_
}, 1000)_x000D_
_x000D_
timer.pause()_x000D_
console.log('isPaused: ', timer.paused)_x000D_
_x000D_
setTimeout(() => {_x000D_
  timer.resume()_x000D_
  console.log('isPaused: ', timer.paused)_x000D_
}, 2500)_x000D_
_x000D_
_x000D_
function Timer (callback, delay) {_x000D_
  let callbackStartTime_x000D_
  let remaining = 0_x000D_
_x000D_
  this.timerId = null_x000D_
  this.paused = false_x000D_
_x000D_
  this.pause = () => {_x000D_
    this.clear()_x000D_
    remaining -= Date.now() - callbackStartTime_x000D_
    this.paused = true_x000D_
  }_x000D_
  this.resume = () => {_x000D_
    window.setTimeout(this.setTimeout.bind(this), remaining)_x000D_
    this.paused = false_x000D_
  }_x000D_
  this.setTimeout = () => {_x000D_
    this.clear()_x000D_
    this.timerId = window.setInterval(() => {_x000D_
      callbackStartTime = Date.now()_x000D_
      callback()_x000D_
    }, delay)_x000D_
  }_x000D_
  this.clear = () => {_x000D_
    window.clearInterval(this.timerId)_x000D_
  }_x000D_
_x000D_
  this.setTimeout()_x000D_
}
_x000D_
_x000D_
_x000D_

The code is written quickly and did not refactored, raise the rating of my answer if you want me to improve the code and give ES2015 version (classes).

Any way to select without causing locking in MySQL?

You may want to read this page of the MySQL manual. How a table gets locked is dependent on what type of table it is.

MyISAM uses table locks to achieve a very high read speed, but if you have an UPDATE statement waiting, then future SELECTS will queue up behind the UPDATE.

InnoDB tables use row-level locking, and you won't have the whole table lock up behind an UPDATE. There are other kind of locking issues associated with InnoDB, but you might find it fits your needs.

How to force R to use a specified factor level as reference in a regression?

Others have mentioned the relevel command which is the best solution if you want to change the base level for all analyses on your data (or are willing to live with changing the data).

If you don't want to change the data (this is a one time change, but in the future you want the default behavior again), then you can use a combination of the C (note uppercase) function to set contrasts and the contr.treatments function with the base argument for choosing which level you want to be the baseline.

For example:

lm( Sepal.Width ~ C(Species,contr.treatment(3, base=2)), data=iris )

How to find the users list in oracle 11g db?

I am not sure what you understand by "execute from the Command line interface", but you're probably looking after the following select statement:

select * from dba_users;

or

select username from dba_users;

How to pass in a react component into another react component to transclude the first component's content?

Actually, your question is how to write a Higher Order Component (HOC). The main goal of using HOC is preventing copy-pasting. You can write your HOC as a purely functional component or as a class here is an example:

    class Child extends Component {
    render() {
        return (
            <div>
                Child
            </div>
        );
    }
}

If you want to write your parent component as a class-based component:

    class Parent extends Component {
    render() {
        return (
            <div>
                {this.props.children}
            </div>
        );
    }
}

If you want to write your parent as a functional component:

    const Parent=props=>{
    return(
        <div>
            {props.children}
        </div>
    )
}

What's the best way to join on the same table twice?

The first method is the proper approach and will do what you need. However, with the inner joins, you will only select rows from Table1 if both phone numbers exist in Table2. You may want to do a LEFT JOIN so that all rows from Table1 are selected. If the phone numbers don't match, then the SomeOtherFields would be null. If you want to make sure you have at least one matching phone number you could then do WHERE t2.PhoneNumber IS NOT NULL OR t3.PhoneNumber IS NOT NULL

The second method could have a problem: what happens if Table2 has both PhoneNumber1 and PhoneNumber2? Which row will be selected? Depending on your data, foreign keys, etc. this may or may not be a problem.

How do I modify a MySQL column to allow NULL?

You want the following:

ALTER TABLE mytable MODIFY mycolumn VARCHAR(255);

Columns are nullable by default. As long as the column is not declared UNIQUE or NOT NULL, there shouldn't be any problems.

Deploying my application at the root in Tomcat

The fastest way.

  1. Make sure you don't have ROOT app deployed, undeploy if you have one

  2. Rename your war to ROOT.war, deploy, thats all, no configuration changes needed

Detect viewport orientation, if orientation is Portrait display alert message advising user of instructions

CCS only

@media (max-width: 1024px) and (orientation: portrait){ /* tablet and smaller */
  body:after{
    position: absolute;
    z-index: 9999;
    width: 100%;
    top: 0;
    bottom: 0;
    content: "";
    background: #212121 url(http://i.stack.imgur.com/sValK.png) 0 0 no-repeat; /* replace with an image that tells the visitor to rotate the device to landscape mode */
    background-size: 100% auto;
    opacity: 0.95;
  }
}

In some cases you may want to add a small piece of code to reload to page after the visitor rotated the device, so that the CSS is rendered properly:

window.onorientationchange = function() { 
    var orientation = window.orientation; 
        switch(orientation) { 
            case 0:
            case 90:
            case -90: window.location.reload(); 
            break; } 
};

Test if executable exists in Python?

See os.path module for some useful functions on pathnames. To check if an existing file is executable, use os.access(path, mode), with the os.X_OK mode.

os.X_OK

Value to include in the mode parameter of access() to determine if path can be executed.

EDIT: The suggested which() implementations are missing one clue - using os.path.join() to build full file names.

Using margin / padding to space <span> from the rest of the <p>

Add this style to your span:

position:relative; 
top: 10px;

Demo: http://jsfiddle.net/BqTUS/3/

What is the current directory in a batch file?

It is the directory from where you start the batch file. E.g. if your batch is in c:\dir1\dir2 and you do cd c:\dir3, then run the batch, the current directory will be c:\dir3.

Padding characters in printf

This one is even simpler and execs no external commands.

$ PROC_NAME="JBoss"
$ PROC_STATUS="UP"
$ printf "%-.20s [%s]\n" "${PROC_NAME}................................" "$PROC_STATUS"

JBoss............... [UP]

LocalDate to java.util.Date and vice versa simplest conversion?

Converting LocalDateTime to java.util.Date

    LocalDateTime localDateTime = LocalDateTime.now();

    ZonedDateTime zonedDateTime = localDateTime.atZone(ZoneOffset.systemDefault());

    Instant instant = zonedDateTime.toInstant();

    Date date = Date.from(instant);

System.out.println("Result Date is : "+date);

How to check if div element is empty

Using plain javascript

 var isEmpty = document.getElementById('cartContent').innerHTML === "";

And if you are using jquery it can be done like

 var isEmpty = $("#cartContent").html() === "";

How to dynamically update labels captions in VBA form?

If you want to use this in VBA:

For i = 1 To X
    UserForm1.Controls("Label" & i).Caption =  MySheet.Cells(i + 1, i).Value
Next

Loop through a comma-separated shell variable

Try this one.

#/bin/bash   
testpid="abc,def,ghij" 
count=`echo $testpid | grep -o ',' | wc -l` # this is not a good way
count=`expr $count + 1` 
while [ $count -gt 0 ]  ; do
     echo $testpid | cut -d ',' -f $i
     count=`expr $count - 1 `
done

In angular $http service, How can I catch the "status" of error?

From the official angular documentation

// Simple GET request example :
$http.get('/someUrl').
  success(function(data, status, headers, config) {
    // this callback will be called asynchronously
    // when the response is available
  }).
  error(function(data, status, headers, config) {
    // called asynchronously if an error occurs
    // or server returns response with an error status.
  });

As you can see first parameter for error callback is data an status is second.

Correct way to remove plugin from Eclipse

Correct way to remove install plug-in from Eclipse/STS :

Go to install folder of eclipse ----> plugin --> select required plugin and remove it.

Ex-

Step 1. 
E:\springsource\sts-3.4.0.RELEASE\plugins

Step 2. 
select and remove related plugins jars.

How to remove last n characters from every element in the R vector

Here's a way with gsub:

cs <- c("foo_bar","bar_foo","apple","beer")
gsub('.{3}$', '', cs)
# [1] "foo_" "bar_" "ap"   "b"

Which characters are valid in CSS class names/selectors?

We can use all characters as class name. Even like # and . Just we have to escape it with \.

_x000D_
_x000D_
.test\.123 {
  color: red;
}

.test\#123 {
  color: blue;
}

.test\@123 {
  color: green;
}

.test\<123 {
  color: brown;
}

.test\`123 {
  color: purple;
}

.test\~123 {
  color: tomato;
}
_x000D_
<div class="test.123">test.123</div>
<div class="test#123">test#123</div>
<div class="test@123">test@123</div>
<div class="test<123">test<123</div>
<div class="test`123">test`123</div>
<div class="test~123">test~123</div>
_x000D_
_x000D_
_x000D_

How to make a Generic Type Cast function

Something like this?

public static T ConvertValue<T>(string value)
{
    return (T)Convert.ChangeType(value, typeof(T));
}

You can then use it like this:

int val = ConvertValue<int>("42");

Edit:

You can even do this more generic and not rely on a string parameter provided the type U implements IConvertible - this means you have to specify two type parameters though:

public static T ConvertValue<T,U>(U value) where U : IConvertible
{
    return (T)Convert.ChangeType(value, typeof(T));
}

I considered catching the InvalidCastException exception that might be raised by Convert.ChangeType() - but what would you return in this case? default(T)? It seems more appropriate having the caller deal with the exception.

How to convert a UTF-8 string into Unicode?

So the issue is that UTF-8 code unit values have been stored as a sequence of 16-bit code units in a C# string. You simply need to verify that each code unit is within the range of a byte, copy those values into bytes, and then convert the new UTF-8 byte sequence into UTF-16.

public static string DecodeFromUtf8(this string utf8String)
{
    // copy the string as UTF-8 bytes.
    byte[] utf8Bytes = new byte[utf8String.Length];
    for (int i=0;i<utf8String.Length;++i) {
        //Debug.Assert( 0 <= utf8String[i] && utf8String[i] <= 255, "the char must be in byte's range");
        utf8Bytes[i] = (byte)utf8String[i];
    }

    return Encoding.UTF8.GetString(utf8Bytes,0,utf8Bytes.Length);
}

DecodeFromUtf8("d\u00C3\u00A9j\u00C3\u00A0"); // déjà

This is easy, however it would be best to find the root cause; the location where someone is copying UTF-8 code units into 16 bit code units. The likely culprit is somebody converting bytes into a C# string using the wrong encoding. E.g. Encoding.Default.GetString(utf8Bytes, 0, utf8Bytes.Length).


Alternatively, if you're sure you know the incorrect encoding which was used to produce the string, and that incorrect encoding transformation was lossless (usually the case if the incorrect encoding is a single byte encoding), then you can simply do the inverse encoding step to get the original UTF-8 data, and then you can do the correct conversion from UTF-8 bytes:

public static string UndoEncodingMistake(string mangledString, Encoding mistake, Encoding correction)
{
    // the inverse of `mistake.GetString(originalBytes);`
    byte[] originalBytes = mistake.GetBytes(mangledString);
    return correction.GetString(originalBytes);
}

UndoEncodingMistake("d\u00C3\u00A9j\u00C3\u00A0", Encoding(1252), Encoding.UTF8);

open new tab(window) by clicking a link in jquery

Try this:

window.open(url, '_blank');

This will open in new tab (if your code is synchronous and in this case it is. in other case it would open a window)

What is the ultimate postal code and zip regex?

.* 

Big Jump forgot about line breaks, blanks and control characters.

International postal codes are a kind of halting problem.

Adding a guideline to the editor in Visual Studio

The registry path for Visual Studio 2008 is the same, but with 9.0 as the version number:

HKEY_CURRENT_USER\Software\Microsoft\VisualStudio\9.0\Text Editor

How to convert a boolean array to an int array

I know you asked for non-looping solutions, but the only solutions I can come up with probably loop internally anyway:

map(int,y)

or:

[i*1 for i in y]

or:

import numpy
y=numpy.array(y)
y*1

How can I stop .gitignore from appearing in the list of untracked files?

You could actually put a line .gitignore into your .gitignore file. This would cause the .gitignore file to be ignored by git. I do not actually think this is a good idea. I think the ignore file should be version controlled and tracked. I'm just putting this out there for completeness.

Saving lists to txt file

@Jon's answer is great and will get you where you need to go. So why is your code printing out what it is. The answer: You're not writing out the contents of your list, but the String representation of your list itself, by an implicit call to Lists.verbList.ToString(). Object.ToString() defines the default behavior you're seeing here.

How to convert empty spaces into null values, using SQL Server?

I solved a similar problem using NULLIF function:

UPDATE table 
SET col1 = NULLIF(col1, '')

From the T-SQL reference:

NULLIF returns the first expression if the two expressions are not equal. If the expressions are equal, NULLIF returns a null value of the type of the first expression.

How to express a NOT IN query with ActiveRecord/Rails?

FYI, In Rails 4, you can use not syntax:

Article.where.not(title: ['Rails 3', 'Rails 5'])

adding css file with jquery

I don't think you can attach down into a window that you are instancing... I KNOW you can't do it if the url's are on different domains (XSS and all that jazz), but you can talk UP from that window and access elements of the parent window assuming they are on the same domain. your best bet is to attach the stylesheet at the page you are loading, and if that page isn't on the same domain, (e.g. trying to restyle some one else's page,) you won't be able to.

test if event handler is bound to an element in jQuery

I had the same need & quickly patched an existing code to be able to do something like this:

 if( $('.scroll').hasHandlers('mouseout') )  // could be click, or '*'...
 { 
   ... code ..
 }

It works for event delegation too:

 if ( $('#main').hasHandlers('click','.simple-search') )  ...

It is available here : jquery-handler-toolkit.js

Python convert decimal to hex

To get a pure hex value this might be useful. It's based on Joe's answer:

def gethex(decimal):
    return hex(decimal)[2:]

Changing the Status Bar Color for specific ViewControllers using Swift in iOS8

I can suggest you a simpler way,

  1. Just call setNeedsStatusBarAppearanceUpdate in viewDidLoad as Apple docs says,

Call this method if the view controller's status bar attributes, such as hidden/unhidden status or style, change. If you call this method within an animation block, the changes are animated along with the rest of the animation block.

  1. Implement preferredStatusBarStyle returning your preferred type.

It worked for me in iOS 10.1.

Objective C

[self setNeedsStatusBarAppearanceUpdate];

-(UIStatusBarStyle)preferredStatusBarStyle {
     return UIStatusBarStyleLightContent;
}

Swift

setNeedsStatusBarAppearanceUpdate()

var preferredStatusBarStyle: UIStatusBarStyle { 
    return .lightContent
}

I am surprised nobody pointed this out. Anyway enjoy :)

Get the first element of each tuple in a list in Python

Use a list comprehension:

res_list = [x[0] for x in rows]

Below is a demonstration:

>>> rows = [(1, 2), (3, 4), (5, 6)]
>>> [x[0] for x in rows]
[1, 3, 5]
>>>

Alternately, you could use unpacking instead of x[0]:

res_list = [x for x,_ in rows]

Below is a demonstration:

>>> lst = [(1, 2), (3, 4), (5, 6)]
>>> [x for x,_ in lst]
[1, 3, 5]
>>>

Both methods practically do the same thing, so you can choose whichever you like.

No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin '...' is therefore not allowed access

Add this to you PHP file or main controller

header("Access-Control-Allow-Origin: http://localhost:9000");

Popup Message boxes

POP UP WINDOWS IN APPLET

hi guys i was searching pop up windows in applet all over the internet but could not find answer for windows.

Although it is simple i am just helping you. Hope you will like it as it is in simpliest form. here's the code :

Filename: PopUpWindow.java for java file and we need html file too.

For applet let us take its popup.html

CODE:

import java.awt.*;

import java.applet.*;

import java.awt.event.*;

public class PopUpWindow extends Applet{

public void init(){

Button open = new Button("open window");

add(open);

Button close = new Button("close window");

add(close);

 Frame f = new Frame("pupup win");

  f.setSize(200,200);




 open.addActionListener(new ActionListener() {

                 public void actionPerformed(ActionEvent e) {
                     if(!f.isShowing()) {
                         f.setVisible(true);
                     }


                 }

              });
 close.addActionListener(new ActionListener() {

                 public void actionPerformed(ActionEvent e) {
                     if(f.isShowing()) {
                        f.setVisible(false);
                     }

                 }

              });

 }

}




/*
<html>

<body>

<APPLET CODE="PopUpWindow" width="" height="">

</APPLET>

</body>

</html>

*/


to run:
$javac PopUpWindow.java && appletviewer popup.html

Iterating over and deleting from Hashtable in Java

You can use Enumeration:

Hashtable<Integer, String> table = ...

Enumeration<Integer> enumKey = table.keys();
while(enumKey.hasMoreElements()) {
    Integer key = enumKey.nextElement();
    String val = table.get(key);
    if(key==0 && val.equals("0"))
        table.remove(key);
}