Programs & Examples On #Urllib3

`urllib3` is a 3rd-party Python HTTP library with thread-safe connection pooling, file post, and more.

What should I use to open a url instead of urlopen in urllib3

urllib3 is a different library from urllib and urllib2. It has lots of additional features to the urllibs in the standard library, if you need them, things like re-using connections. The documentation is here: https://urllib3.readthedocs.org/

If you'd like to use urllib3, you'll need to pip install urllib3. A basic example looks like this:

from bs4 import BeautifulSoup
import urllib3

http = urllib3.PoolManager()

url = 'http://www.thefamouspeople.com/singers.php'
response = http.request('GET', url)
soup = BeautifulSoup(response.data)

Suppress InsecureRequestWarning: Unverified HTTPS request is being made in Python2.6

This is the answer in 2017. urllib3 not a part of requests anymore

import urllib3
urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)

Python Requests throwing SSLError

This is similar to @rafael-almeida 's answer, but I want to point out that as of requests 2.11+, there are not 3 values that verify can take, there are actually 4:

  • True: validates against requests's internal trusted CAs.
  • False: bypasses certificate validation completely. (Not recommended)
  • Path to a CA_BUNDLE file. requests will use this to validate the server's certificates.
  • Path to a directory containing public certificate files. requests will use this to validate the server's certificates.

The rest of my answer is about #4, how to use a directory containing certificates to validate:

Obtain the public certificates needed and place them in a directory.

Strictly speaking, you probably "should" use an out-of-band method of obtaining the certificates, but you could also just download them using any browser.

If the server uses a certificate chain, be sure to obtain every single certificate in the chain.

According to the requests documentation, the directory containing the certificates must first be processed with the "rehash" utility (openssl rehash).

(This requires openssl 1.1.1+, and not all Windows openssl implementations support rehash. If openssl rehash won't work for you, you could try running the rehash ruby script at https://github.com/ruby/openssl/blob/master/sample/c_rehash.rb , though I haven't tried this. )

I had some trouble with getting requests to recognize my certificates, but after I used the openssl x509 -outform PEM command to convert the certs to Base64 .pem format, everything worked perfectly.

You can also just do lazy rehashing:

try:
    # As long as the certificates in the certs directory are in the OS's certificate store, `verify=True` is fine.
    return requests.get(url, auth=auth, verify=True)
except requests.exceptions.SSLError:
    subprocess.run(f"openssl rehash -compat -v my_certs_dir", shell=True, check=True)
    return requests.get(url, auth=auth, verify="my_certs_dir")

Output single character in C

As mentioned in one of the other answers, you can use putc(int c, FILE *stream), putchar(int c) or fputc(int c, FILE *stream) for this purpose.

What's important to note is that using any of the above functions is from some to signicantly faster than using any of the format-parsing functions like printf.

Using printf is like using a machine gun to fire one bullet.

Plot multiple columns on the same graph in R

To select columns to plot, I added 2 lines to Vincent Zoonekynd's answer:

#convert to tall/long format(from wide format)
col_plot = c("A","B")
dlong <- melt(d[,c("Xax", col_plot)], id.vars="Xax")  

#"value" and "variable" are default output column names of melt()
ggplot(dlong, aes(Xax,value, col=variable)) +
  geom_point() + 
  geom_smooth()

Google "tidy data" to know more about tall(or long)/wide format.

Clearing localStorage in javascript?

This code here you give a list of strings of keys that you don't want to delete, then it filters those from all the keys in local storage then deletes the others.

const allKeys = Object.keys(localStorage);

const toBeDeleted = allKeys.filter(value => {
  return !this.doNotDeleteList.includes(value);
});

toBeDeleted.forEach(value => {
  localStorage.removeItem(value);
});

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

This question is some years old but i came via a duplicate to it. I want to suggest a more general solution too. If you know you always have a fixed number of ancestors you can use some self joins as already suggested in the answers. If you want a generic approach go on reading.

What you need here is called Quotient in relational Algebra. The Quotient is more or less the reversal of the Cartesian Product (or Cross Join in SQL).

Let's say your ancestor set A is (i use a table notation here, i think this is better for understanding)

ancestry
-----------
'England'
'France'
'Germany'

and your user set U is

user_id
--------
   1
   2
   3

The cartesian product C=AxU is then:

user_id  |  ancestry
---------+-----------
   1     | 'England'
   1     | 'France'
   1     | 'Germany'
   2     | 'England'
   2     | 'France'
   2     | 'Germany'
   3     | 'England'
   3     | 'France'
   3     | 'Germany'

If you calculate the set quotient U=C/A then you get

user_id
--------
   1
   2
   3

If you redo the cartesian product UXA you will get C again. But note that for a set T, (T/A)xA will not necessarily reproduce T. For example, if T is

user_id  |  ancestry
---------+-----------
   1     | 'England'
   1     | 'France'
   1     | 'Germany'
   2     | 'England'
   2     | 'France'

then (T/A) is

user_id
--------
   1

(T/A)xA will then be

user_id  |  ancestry
---------+------------
   1     | 'England'
   1     | 'France'
   1     | 'Germany'

Note that the records for user_id=2 have been eliminated by the Quotient and Cartesian Product operations.

Your question is: Which user_id has ancestors from all countries in your ancestor set? In other words you want U=T/A where T is your original set (or your table).

To implement the quotient in SQL you have to do 4 steps:

  1. Create the Cartesian Product of your ancestry set and the set of all user_ids.
  2. Find all records in the Cartesian Product which have no partner in the original set (Left Join)
  3. Extract the user_ids from the resultset of 2)
  4. Return all user_ids from the original set which are not included in the result set of 3)

So let's do it step by step. I will use TSQL syntax (Microsoft SQL server) but it should easily be adaptable to other DBMS. As a name for the table (user_id, ancestry) i choose ancestor

CREATE TABLE ancestry_set (ancestry nvarchar(25))
INSERT INTO ancestry_set (ancestry) VALUES ('England')
INSERT INTO ancestry_set (ancestry) VALUES ('France')
INSERT INTO ancestry_set (ancestry) VALUES ('Germany')

CREATE TABLE ancestor ([user_id] int, ancestry nvarchar(25))
INSERT INTO ancestor ([user_id],ancestry) VALUES (1,'England')
INSERT INTO ancestor ([user_id],ancestry) VALUES(1,'Ireland')
INSERT INTO ancestor ([user_id],ancestry) VALUES(2,'France')
INSERT INTO ancestor ([user_id],ancestry) VALUES(3,'Germany')
INSERT INTO ancestor ([user_id],ancestry) VALUES(3,'Poland')
INSERT INTO ancestor ([user_id],ancestry) VALUES(4,'England')
INSERT INTO ancestor ([user_id],ancestry) VALUES(4,'France')
INSERT INTO ancestor ([user_id],ancestry) VALUES(4,'Germany')
INSERT INTO ancestor ([user_id],ancestry) VALUES(5,'France')
INSERT INTO ancestor ([user_id],ancestry) VALUES(5,'Germany')

1) Create the Cartesian Product of your ancestry set and the set of all user_ids.

SELECT a.[user_id],s.ancestry
FROM ancestor a, ancestry_set s
GROUP BY a.[user_id],s.ancestry

2) Find all records in the Cartesian Product which have no partner in the original set (Left Join) and

3) Extract the user_ids from the resultset of 2)

SELECT DISTINCT cp.[user_id]
FROM (SELECT a.[user_id],s.ancestry
      FROM ancestor a, ancestry_set s
      GROUP BY a.[user_id],s.ancestry) cp
   LEFT JOIN ancestor a ON cp.[user_id]=a.[user_id] AND cp.ancestry=a.ancestry
WHERE a.[user_id] is null

4) Return all user_ids from the original set which are not included in the result set of 3)

SELECT DISTINCT [user_id]
FROM ancestor
WHERE [user_id] NOT IN (
   SELECT DISTINCT cp.[user_id]
   FROM (SELECT a.[user_id],s.ancestry
         FROM ancestor a, ancestry_set s
         GROUP BY a.[user_id],s.ancestry) cp
   LEFT JOIN ancestor a ON cp.[user_id]=a.[user_id] AND cp.ancestry=a.ancestry
   WHERE a.[user_id] is null
   )

Writing a new line to file in PHP (line feed)

Use PHP_EOL which outputs \r\n or \n depending on the OS.

Get clicked element using jQuery on event?

A simple way is to pass the data attribute to your HTML tag.

Example:

<div data-id='tagid' class="clickElem"></div>

<script>
$(document).on("click",".appDetails", function () {
   var clickedBtnID = $(this).attr('data');
   alert('you clicked on button #' + clickedBtnID);
});
</script>

How to avoid precompiled headers

You can always disable the use of pre-compiled headers in the project settings.

Instructions for VS 2010 (should be similar for other versions of VS):

Select your project, use the "Project -> Properties" menu and go to the "Configuration Properties -> C/C++ -> Precompiled Headers" section, then change the "Precompiled Header" setting to "Not Using Precompiled Headers" option.


If you are only trying to setup a minimal Visual Studio project for simple C++ command-line programs (such as those developed in introductory C++ programming classes), you can create an empty C++ project.

How do I compare 2 rows from the same table (SQL Server)?

SELECT * FROM A AS b INNER JOIN A AS c ON b.a = c.a
WHERE b.a = 'some column value'

Writing binary number system in C code

Prefix you literal with 0b like in

int i = 0b11111111;

See here.

Fast query runs slow in SSRS

Add this to the end of your proc: option(recompile)

This will make the report run almost as fast as the stored procedure

Disabled href tag

Tips 1: Using CSS pointer-events: none;

Tips 2: Using JavaScript javascript:void(0) (This is a best practice)

<a href="javascript:void(0)"></a>

Tips 1: Using Jquery $('selector').attr("disabled","disabled");

PHP CURL & HTTPS

One important note, the solution mentioned above will not work on local host, you have to upload your code to server and then it will work. I was getting no error, than bad request, the problem was I was using localhost (test.dev,myproject.git). Both solution above work, the solution that uses SSL cert is recommended.

  1. Go to https://curl.haxx.se/docs/caextract.html, download the latest cacert.pem. Store is somewhere (not in public folder - but will work regardless)

  2. Use this code

".$result; //echo "
Path:".$_SERVER['DOCUMENT_ROOT'] . "/ssl/cacert.pem"; // this is for troubleshooting only ?>
  1. Upload the code to live server and test.

AngularJS - Building a dynamic table based on a json

<table class="table table-striped table-condensed table-hover">
    <thead>
    <tr>
        <th ng-repeat="header in headers | filter:headerFilter | orderBy:headerOrder" width="{{header.width}}">{{header.label}}</th>
    </tr>
    </thead>
    <tbody>
    <tr ng-repeat="user in users" ng-class-odd="'trOdd'" ng-class-even="'trEven'" ng-dblclick="rowDoubleClicked(user)">
        <td ng-repeat="(key,val) in user | orderBy:userOrder(key)">{{val}}</td>
    </tr>
    </tbody>
    <tfoot>

    </tfoot>
</table>

refer this https://gist.github.com/ebellinger/4399082

Replace deprecated preg_replace /e with preg_replace_callback

You can use an anonymous function to pass the matches to your function:

$result = preg_replace_callback(
    "/\{([<>])([a-zA-Z0-9_]*)(\?{0,1})([a-zA-Z0-9_]*)\}(.*)\{\\1\/\\2\}/isU",
    function($m) { return CallFunction($m[1], $m[2], $m[3], $m[4], $m[5]); },
    $result
);

Apart from being faster, this will also properly handle double quotes in your string. Your current code using /e would convert a double quote " into \".

How to connect to a secure website using SSL in Java with a pkcs12 file?

This example shows how you can layer SSL on top of an existing socket, obtaining the client cert from a PKCS#12 file. It is appropriate when you need to connect to an upstream server via a proxy, and you want to handle the full protocol by yourself.

Essentially, however, once you have the SSL Context, you can apply it to an HttpsURLConnection, etc, etc.

KeyStore ks = KeyStore.getInstance("PKCS12");
InputStream is = ...;
char[] ksp = storePassword.toCharArray();
ks.load(is, ksp);
KeyManagerFactory kmf = KeyManagerFactory.getInstance("SunX509");
char[] kp = keyPassword.toCharArray();
kmf.init(ks, kp);
sslContext = SSLContext.getInstance("SSLv3");
sslContext.init(kmf.getKeyManagers(), null, null);
SSLSocketFactory factory = sslContext.getSocketFactory();
SSLSocket sslsocket = (SSLSocket) factory.createSocket(socket, socket
    .getInetAddress().getHostName(), socket.getPort(), true);
sslsocket.setUseClientMode(true);
sslsocket.setSoTimeout(soTimeout);
sslsocket.startHandshake();

How to create a String with carriage returns?

The fastest way I know to generate a new-line character in Java is: String.format("%n")

Of course you can put whatever you want around the %n like:

String.format("line1%nline2")

Or even if you have a lot of lines:

String.format("%s%n%s%n%s%n%s", "line1", "line2", "line3", "line4")

How do I "Add Existing Item" an entire directory structure in Visual Studio?

This is what I do:

  1. Right click on solution -> Add -> Existing Website...
  2. Choose the folder where your website is. Just the root folder of the site.

Then everything will be added on your solution from folders to files, and files inside those folders.

How to add new item to hash

hash_items = {:item => 1}
puts hash_items 
#hash_items will give you {:item => 1}

hash_items.merge!({:item => 2})
puts hash_items 
#hash_items will give you {:item => 1, :item => 2}

hash_items.merge({:item => 2})
puts hash_items 
#hash_items will give you {:item => 1, :item => 2}, but the original variable will be the same old one. 

Change color of bootstrap navbar on hover link?

Use Come thing link this , This is Based on Bootstrap 3.0

.navbar-default .navbar-nav > .active > a, .navbar-default .navbar-nav > .active > a:hover, .navbar-default .navbar-nav > .active > a:focus {
    background-color: #977EBD;
    color: #FFFFFF;
}

.navbar-default .navbar-nav > li > a:hover, .navbar-default .navbar-nav > li > a:focus {
    background-color: #977EBD;
    color: #FFFFFF;
}

phpexcel to download

 header('Content-type: application/vnd.ms-excel');

 header('Content-Disposition: attachment; filename="file.xlsx"');

 header('Cache-Control: max-age=0');

 header ('Expires: Mon, 26 Jul 1997 05:00:00 GMT');

 header ('Last-Modified: '.gmdate('D, d M Y H:i:s').' GMT');

 header ('Cache-Control: cache, must-revalidate');

 header ('Pragma: public');

 $objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel5');

 $objWriter->save('php://output');

How to vertically align label and input in Bootstrap 3?

The problem is that your <label> is inside of an <h2> tag, and header tags have a margin set by the default stylesheet.

Strings as Primary Keys in SQL Database

There could be a very big misunderstanding related to string in the database are. Almost everyone has thought that database representation of numbers are more compact than for strings. They think that in db-s numbers are represented as in the memory. BUT it is not true. In most cases number representation is more close to A string like representation as to other.

The speed of using number or string is more dependent on the indexing then the type itself.

How do I set proxy for chrome in python webdriver?

Its working for me...

from selenium import webdriver

PROXY = "23.23.23.23:3128" # IP:PORT or HOST:PORT

chrome_options = webdriver.ChromeOptions()
chrome_options.add_argument('--proxy-server=http://%s' % PROXY)

chrome = webdriver.Chrome(chrome_options=chrome_options)
chrome.get("http://whatismyipaddress.com")

Proper way to catch exception from JSON.parse

We can check error & 404 statusCode, and use try {} catch (err) {}.

You can try this :

_x000D_
_x000D_
const req = new XMLHttpRequest();_x000D_
req.onreadystatechange = function() {_x000D_
    if (req.status == 404) {_x000D_
        console.log("404");_x000D_
        return false;_x000D_
    }_x000D_
_x000D_
    if (!(req.readyState == 4 && req.status == 200))_x000D_
        return false;_x000D_
_x000D_
    const json = (function(raw) {_x000D_
        try {_x000D_
            return JSON.parse(raw);_x000D_
        } catch (err) {_x000D_
            return false;_x000D_
        }_x000D_
    })(req.responseText);_x000D_
_x000D_
    if (!json)_x000D_
        return false;_x000D_
_x000D_
    document.body.innerHTML = "Your city : " + json.city + "<br>Your isp : " + json.org;_x000D_
};_x000D_
req.open("GET", "https://ipapi.co/json/", true);_x000D_
req.send();
_x000D_
_x000D_
_x000D_

Read more :

How to query a CLOB column in Oracle

If it's a CLOB why can't we to_char the column and then search normally ?

Create a table

CREATE TABLE MY_TABLE(Id integer PRIMARY KEY, Name varchar2(20), message clob);

Create few records in this table

INSERT INTO MY_TABLE VALUES(1,'Tom','Hi This is Row one');
INSERT INTO MY_TABLE VALUES(2,'Lucy', 'Hi This is Row two');
INSERT INTO MY_TABLE VALUES(3,'Frank', 'Hi This is Row three');
INSERT INTO MY_TABLE VALUES(4,'Jane', 'Hi This is Row four');
INSERT INTO MY_TABLE VALUES(5,'Robert', 'Hi This is Row five');
COMMIT;

Search in the clob column

SELECT * FROM MY_TABLE where to_char(message) like '%e%';

Results

ID   NAME    MESSAGE   
===============================  
1    Tom     Hi This is Row one         
3    Frank   Hi This is Row three
5    Robert  Hi This is Row five

Difference between Static and final?

static means it belongs to the class not an instance, this means that there is only one copy of that variable/method shared between all instances of a particular Class.

public class MyClass {
    public static int myVariable = 0; 
}

//Now in some other code creating two instances of MyClass
//and altering the variable will affect all instances

MyClass instance1 = new MyClass();
MyClass instance2 = new MyClass();

MyClass.myVariable = 5;  //This change is reflected in both instances

final is entirely unrelated, it is a way of defining a once only initialization. You can either initialize when defining the variable or within the constructor, nowhere else.

note A note on final methods and final classes, this is a way of explicitly stating that the method or class can not be overridden / extended respectively.

Extra Reading So on the topic of static, we were talking about the other uses it may have, it is sometimes used in static blocks. When using static variables it is sometimes necessary to set these variables up before using the class, but unfortunately you do not get a constructor. This is where the static keyword comes in.

public class MyClass {

    public static List<String> cars = new ArrayList<String>();

    static {
        cars.add("Ferrari");
        cars.add("Scoda");
    }

}

public class TestClass {

    public static void main(String args[]) {
        System.out.println(MyClass.cars.get(0));  //This will print Ferrari
    }
}

You must not get this confused with instance initializer blocks which are called before the constructor per instance.

Convert byte to string in Java

You can use printf:

System.out.printf("string %c\n", 0x63);

You can as well create a String with such formatting, using String#format:

String s = String.format("string %c", 0x63);

PostgreSQL Crosstab Query

You can use the crosstab() function of the additional module tablefunc - which you have to install once per database. Since PostgreSQL 9.1 you can use CREATE EXTENSION for that:

CREATE EXTENSION tablefunc;

In your case, I believe it would look something like this:

CREATE TABLE t (Section CHAR(1), Status VARCHAR(10), Count integer);

INSERT INTO t VALUES ('A', 'Active',   1);
INSERT INTO t VALUES ('A', 'Inactive', 2);
INSERT INTO t VALUES ('B', 'Active',   4);
INSERT INTO t VALUES ('B', 'Inactive', 5);

SELECT row_name AS Section,
       category_1::integer AS Active,
       category_2::integer AS Inactive
FROM crosstab('select section::text, status, count::text from t',2)
            AS ct (row_name text, category_1 text, category_2 text);

Laravel - Session store not set on request

I'm using laravel 7.x and this problem arose.. the following fixed it:

go to kernel.php and add these 2 classes to protected $middleware

\Illuminate\Session\Middleware\StartSession::class, \Illuminate\View\Middleware\ShareErrorsFromSession::class,

java: Class.isInstance vs Class.isAssignableFrom

Both answers are in the ballpark but neither is a complete answer.

MyClass.class.isInstance(obj) is for checking an instance. It returns true when the parameter obj is non-null and can be cast to MyClass without raising a ClassCastException. In other words, obj is an instance of MyClass or its subclasses.

MyClass.class.isAssignableFrom(Other.class) will return true if MyClass is the same as, or a superclass or superinterface of, Other. Other can be a class or an interface. It answers true if Other can be converted to a MyClass.

A little code to demonstrate:

public class NewMain
{
    public static void main(String[] args)
    {
        NewMain nm = new NewMain();
        nm.doit();
    }

    class A { }

    class B extends A { }

    public void doit()
    {
        A myA = new A();
        B myB = new B();
        A[] aArr = new A[0];
        B[] bArr = new B[0];

        System.out.println("b instanceof a: " + (myB instanceof A)); // true
        System.out.println("b isInstance a: " + A.class.isInstance(myB)); //true
        System.out.println("a isInstance b: " + B.class.isInstance(myA)); //false
        System.out.println("b isAssignableFrom a: " + A.class.isAssignableFrom(B.class)); //true
        System.out.println("a isAssignableFrom b: " + B.class.isAssignableFrom(A.class)); //false
        System.out.println("bArr isInstance A: " + A.class.isInstance(bArr)); //false
        System.out.println("bArr isInstance aArr: " + aArr.getClass().isInstance(bArr)); //true
        System.out.println("bArr isAssignableFrom aArr: " + aArr.getClass().isAssignableFrom(bArr.getClass())); //true
    }
}

How to set a Fragment tag by code?

Yes. So the only way is at transaction time, e.g. using add, replace, or as part of the layout.

I determined this through an examination of the compatibility sources as I briefly looked for similar at some point in the past.

How do I make a simple makefile for gcc on Linux?

all: program
program.o: program.h headers.h

is enough. the rest is implicit

Getting date format m-d-Y H:i:s.u from milliseconds

I benched a few different ways:

1) microtime + sscanf + date:

sscanf(microtime(), '0.%6s00 %s', $usec, $sec);
$date = date('Y-m-d H:i:s.', $sec) . $usec;

I'm not sure why microtime() returns 10 chars (0.dddddd00) for the microseconds part but maybe someone can tell me ?

$start_ts = microtime(true); for($i = 0; $i < 10000000; $i++) { sscanf(microtime(), '0.%6s00 %s', $usec, $sec); $date = date('Y-m-d H:i:s.', $sec) . $usec; } var_dump((microtime(true) - $start_ts)*1000 . ' ms');
string(18) "22372.335910797 ms" // macOS PHP 5.6.30
string(18) "16772.964000702 ms" // Linux PHP 5.4.16
string(18) "10382.229089737 ms" // Linux PHP 7.3.11 (same linux box as above)

2) DateTime::createFromFormat + Datetime->format:

$now = new DateTime('NOW');
$date = $now->format('Y-m-d H:i:s.u');

not working in PHP 5.x ...

$start_ts = microtime(true); for($i = 0; $i < 10000000; $i++) { $now = new DateTime('NOW'); $date = $now->format('Y-m-d H:i:s.u'); } var_dump((microtime(true) - $start_ts)*1000 . ' ms');
string(18) "45801.825046539 ms" // macOS PHP 5.6.30 (ms not working)
string(18) "21180.155038834 ms" // Linux PHP 5.4.16 (ms not working)
string(18) "11879.796028137 ms" // Linux PHP 7.3.11 (same linux box as above)

3) gettimeofday + date:

$time = gettimeofday();
$date = date('Y-m-d H:i:s.', $time['sec']) . $time['usec'];

-

$start_ts = microtime(true); for($i = 0; $i < 10000000; $i++) { $time = gettimeofday(); $date = date('Y-m-d H:i:s.', $time['sec']) . $time['usec']; } var_dump((microtime(true) - $start_ts)*1000 . ' ms');
string(18) "23706.788063049 ms" // macOS PHP 5.6.30
string(18) "14984.534025192 ms" // Linux PHP 5.4.16
string(18) "7799.1390228271 ms" // Linux PHP 7.3.11 (same linux box as above)

4) microtime + number_format + DateTime::createFromFormat + DateTime->format:

$now = DateTime::createFromFormat('U.u', number_format(microtime(true), 6, '.', ''));
$date = $now->format('Y-m-d H:i:s.u');

-

$start_ts = microtime(true); for($i = 0; $i < 10000000; $i++) { $now = DateTime::createFromFormat('U.u', number_format(microtime(true), 6, '.', '')); $date = $now->format('Y-m-d H:i:s.u'); } var_dump((microtime(true) - $start_ts)*1000 . ' ms');
string(18) "83326.496124268 ms" // macOS PHP 5.6.30
string(18) "61982.603788376 ms" // Linux PHP 5.4.16
string(16) "19107.1870327 ms" // Linux PHP 7.3.11 (same linux box as above)

5) microtime + sprintf + DateTime::createFromFormat + DateTime->format:

$now = DateTime::createFromFormat('U.u', sprintf('%.6f', microtime(true)));
$date = $now->format('Y-m-d H:i:s.u');

-

$start_ts = microtime(true); for($i = 0; $i < 10000000; $i++) { $now = DateTime::createFromFormat('U.u', sprintf('%.6f', microtime(true))); $date = $now->format('Y-m-d H:i:s.u'); } var_dump((microtime(true) - $start_ts)*1000 . ' ms');
string(18) "79387.331962585 ms" // macOS PHP 5.6.30
string(18) "60734.437942505 ms" // Linux PHP 5.4.16
string(18) "18594.941139221 ms" // Linux PHP 7.3.11 (same linux box as above)

Can't get private key with openssl (no start line:pem_lib.c:703:Expecting: ANY PRIVATE KEY)

My two cents: came across the same error message in RHEL7.3 while running the openssl command with root CA certificate. The reason being, while downloading the certificate from AD server, Encoding was selected as DER instead of Base64. Once the proper version of encoding was selected for the new certificate download, error was resolved

Hope this helps for new users :-)

What's the difference between 'int?' and 'int' in C#?

the symbol ? after the int means that it can be nullable.

The ? symbol is usually used in situations whereby the variable can accept a null or an integer or alternatively, return an integer or null.

Hope the context of usage helps. In this way you are not restricted to solely dealing with integers.

How to get CSS to select ID that begins with a string (not in Javascript)?

[id^=product]

^= indicates "starts with". Conversely, $= indicates "ends with".

The symbols are actually borrowed from Regex syntax, where ^ and $ mean "start of string" and "end of string" respectively.

See the specs for full information.

Adjust width and height of iframe to fit with content in it

This is a solid proof solution

function resizer(id)
{

var doc=document.getElementById(id).contentWindow.document;
var body_ = doc.body, html_ = doc.documentElement;

var height = Math.max( body_.scrollHeight, body_.offsetHeight, html_.clientHeight, html_.scrollHeight, html_.offsetHeight );
var width  = Math.max( body_.scrollWidth, body_.offsetWidth, html_.clientWidth, html_.scrollWidth, html_.offsetWidth );

document.getElementById(id).style.height=height;
document.getElementById(id).style.width=width;

}

the html

<IFRAME SRC="blah.php" id="iframe1"  onLoad="resizer('iframe1');"></iframe>

File Upload with Angular Material

I find a way to avoid styling my own choose file button.

Because I'm using flowjs for resumable upload, I'm able to use the "flow-btn" directive from ng-flow, which gives a choose file button with material design style.

Note that wrapping the input element inside a md-button won't work.

Run a single test method with maven

You can run specific test class(es) and method(s) using the following syntax:

  1. full package : mvn test -Dtest="com.oracle.tests.**"

  2. all method in a class : mvn test -Dtest=CLASS_NAME1

  3. single method from single class :mvn test -Dtest=CLASS_NAME1#METHOD_NAME1

  4. multiple method from multiple class : mvn test -Dtest=CLASS_NAME1#METHOD_NAME1,CLASS_NAME2#METHOD_NAME2

How do I use SELECT GROUP BY in DataTable.Select(Expression)?

dt = dt.AsEnumerable().GroupBy(r => r.Field<int>("ID")).Select(g => g.First()).CopyToDataTable();

How to do a less than or equal to filter in Django queryset?

Less than or equal:

User.objects.filter(userprofile__level__lte=0)

Greater than or equal:

User.objects.filter(userprofile__level__gte=0)

Likewise, lt for less than and gt for greater than. You can find them all in the documentation.

How can I control the width of a label tag?

Giving width to Label is not a proper way. you should take one div or table structure to manage this. but still if you don't want to change your whole code then you can use following code.

label {
  width:200px;
  float: left;
}

Where to find htdocs in XAMPP Mac

In the "volumes" tab, you have to mount it first. Then it appears on the desktop as if it were an external USB. All the data is inside it. :D

Convert a file path to Uri in Android

Normal answer for this question if you really want to get something like content//media/external/video/media/18576 (e.g. for your video mp4 absolute path) and not just file///storage/emulated/0/DCIM/Camera/20141219_133139.mp4:

MediaScannerConnection.scanFile(this,
          new String[] { file.getAbsolutePath() }, null,
          new MediaScannerConnection.OnScanCompletedListener() {
      public void onScanCompleted(String path, Uri uri) {
          Log.i("onScanCompleted", uri.getPath());
      }
 });

Accepted answer is wrong (cause it will not return content//media/external/video/media/*)

Uri.fromFile(file).toString() only returns something like file///storage/emulated/0/* which is a simple absolute path of a file on the sdcard but with file// prefix (scheme)

You can also get content uri using MediaStore database of Android

TEST (what returns Uri.fromFile and what returns MediaScannerConnection):

File videoFile = new File("/storage/emulated/0/video.mp4");

Log.i(TAG, Uri.fromFile(videoFile).toString());

MediaScannerConnection.scanFile(this, new String[] { videoFile.getAbsolutePath() }, null,
        (path, uri) -> Log.i(TAG, uri.toString()));

Output:

I/Test: file:///storage/emulated/0/video.mp4

I/Test: content://media/external/video/media/268927

Error in plot.new() : figure margins too large, Scatter plot

Every time you are creating plots you might get this error - "Error in plot.new() : figure margins too large". To avoid such errors you can first check par("mar") output. You should be getting:

[1] 5.1 4.1 4.1 2.1

To change that write:

par(mar=c(1,1,1,1))

This should rectify the error. Or else you can change the values accordingly.

Hope this works for you.

How do I truly reset every setting in Visual Studio 2012?

Click on Tools menu > Import and Export Settings > Reset all settings > Next > "No, just reset settings, overwriting all current settings" > Next > Finish.

How to implement infinity in Java?

To use Infinity, you can use Double which supports Infinity: -

    System.out.println(Double.POSITIVE_INFINITY);
    System.out.println(Double.POSITIVE_INFINITY * -1);
    System.out.println(Double.NEGATIVE_INFINITY);

    System.out.println(Double.POSITIVE_INFINITY - Double.NEGATIVE_INFINITY);
    System.out.println(Double.POSITIVE_INFINITY - Double.POSITIVE_INFINITY);

OUTPUT: -

Infinity
-Infinity
-Infinity

Infinity 
NaN

GCC: array type has incomplete element type

It's the array that's causing trouble in:

void print_graph(g_node graph_node[], double weight[][], int nodes);

The second and subsequent dimensions must be given:

void print_graph(g_node graph_node[], double weight[][32], int nodes);

Or you can just give a pointer to pointer:

void print_graph(g_node graph_node[], double **weight, int nodes);

However, although they look similar, those are very different internally.

If you're using C99, you can use variably-qualified arrays. Quoting an example from the C99 standard (section §6.7.5.2 Array Declarators):

void fvla(int m, int C[m][m]); // valid: VLA with prototype scope

void fvla(int m, int C[m][m])  // valid: adjusted to auto pointer to VLA
{
    typedef int VLA[m][m];     // valid: block scope typedef VLA
    struct tag {
        int (*y)[n];           // invalid: y not ordinary identifier
        int z[n];              // invalid: z not ordinary identifier
    };
    int D[m];                  // valid: auto VLA
    static int E[m];           // invalid: static block scope VLA
    extern int F[m];           // invalid: F has linkage and is VLA
    int (*s)[m];               // valid: auto pointer to VLA
    extern int (*r)[m];        // invalid: r has linkage and points to VLA
    static int (*q)[m] = &B;   // valid: q is a static block pointer to VLA
}

Question in comments

[...] In my main(), the variable I am trying to pass into the function is a double array[][], so how would I pass that into the function? Passing array[0][0] into it gives me incompatible argument type, as does &array and &array[0][0].

In your main(), the variable should be:

double array[10][20];

or something faintly similar; maybe

double array[][20] = { { 1.0, 0.0, ... }, ... };

You should be able to pass that with code like this:

typedef struct graph_node
{
    int X;
    int Y;
    int active;
} g_node;

void print_graph(g_node graph_node[], double weight[][20], int nodes);

int main(void)
{
    g_node g[10];
    double array[10][20];
    int n = 10;

    print_graph(g, array, n);
    return 0;
}

That compiles (to object code) cleanly with GCC 4.2 (i686-apple-darwin11-llvm-gcc-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.9.00)) and also with GCC 4.7.0 on Mac OS X 10.7.3 using the command line:

/usr/bin/gcc -O3 -g -std=c99 -Wall -Wextra -c zzz.c

Single vs Double quotes (' vs ")

If it's all the same, perhaps using single-quotes is better since it doesn't require holding down the shift key. Fewer keystrokes == less chance of RSI.

"Port 4200 is already in use" when running the ng serve command

It seems like another program is using your default port 4200. Good thing is, ports above 4200 are usually free. Just pick another one. For example:

ng serve --port 4210

How can I select from list of values in SQL Server

This works on SQL Server 2005 and if there is maximal number:

SELECT * 
FROM
  (SELECT ROW_NUMBER() OVER(ORDER BY a.id) NUMBER
  FROM syscomments a
  CROSS JOIN syscomments b) c
WHERE c.NUMBER IN (1,4,6,7,9)

Spring Security exclude url patterns in security annotation configurartion

specifying the "antMatcher" before "authorizeRequests()" like below will restrict the authenticaiton to only those URLs specified in "antMatcher"

http.csrf().disable() .antMatcher("/apiurlneedsauth/**").authorizeRequests().

Registry key Error: Java version has value '1.8', but '1.7' is required

just did this and it worked

HKLM > SOFTWARE > JavaSoft > Java Runtime Environment

just manually change current version to 1.7 .

lol ... but it worked!

Java Best Practices to Prevent Cross Site Scripting

Use both. In fact refer a guide like the OWASP XSS Prevention cheat sheet, on the possible cases for usage of output encoding and input validation.

Input validation helps when you cannot rely on output encoding in certain cases. For instance, you're better off validating inputs appearing in URLs rather than encoding the URLs themselves (Apache will not serve a URL that is url-encoded). Or for that matter, validate inputs that appear in JavaScript expressions.

Ultimately, a simple thumb rule will help - if you do not trust user input enough or if you suspect that certain sources can result in XSS attacks despite output encoding, validate it against a whitelist.

Do take a look at the OWASP ESAPI source code on how the output encoders and input validators are written in a security library.

Maven Install on Mac OS X

  1. Open terminal
  2. Just use brew command to install maven
brew install maven
  1. After the download and install finished. Check for the maven version
mvn -version

Here you go !!! Now you have successfully installed maven on your mac os.

Stop absolutely positioned div from overlapping text

_x000D_
_x000D_
<div style="position: relative; width:600px;">_x000D_
        <p>Content of unknown length</p>_x000D_
        <div>Content of unknown height</div>_x000D_
        <div id="spacer" style="width: 200px; height: 100px; float:left; display:inline-block"></div>_x000D_
        <div class="btn" style="position: absolute; right: 0; bottom: 0; width: 200px; height: 100px;"></div>_x000D_
    </div>
_x000D_
_x000D_
_x000D_

This should be a comment but I don't have enough reputation yet. The solution works, but visual studio code told me the following putting it into a css sheet:

inline-block is ignored due to the float. If 'float' has a value other than 'none', the box is floated and 'display' is treated as 'block'

So I did it like this

.spacer {
    float: left;
    height: 20px;
    width: 200px;
}

And it works just as well.

how to pass command line arguments to main method dynamically

Run ---> Debug Configuration ---> YourConfiguration ---> Arguments tab

enter image description here

npm install errors with Error: ENOENT, chmod

  1. Install latest version of node
  2. Run: npm cache clean
  3. Run: npm install cordova -g

Javascript: The prettiest way to compare one value against multiple values

Don't try to be too sneaky, especially when it needlessly affects performance. If you really have a whole heap of comparisons to do, just format it nicely.

if (foobar === foo ||
    foobar === bar ||
    foobar === baz ||
    foobar === pew) {
     //do something
}

How do I get a Cron like scheduler in Python?

Another trivial solution would be:

from aqcron import At
from time import sleep
from datetime import datetime

# Event scheduling
event_1 = At( second=5 )
event_2 = At( second=[0,20,40] )

while True:
    now = datetime.now()

    # Event check
    if now in event_1: print "event_1"
    if now in event_2: print "event_2"

    sleep(1)

And the class aqcron.At is:

# aqcron.py

class At(object):
    def __init__(self, year=None,    month=None,
                 day=None,     weekday=None,
                 hour=None,    minute=None,
                 second=None):
        loc = locals()
        loc.pop("self")
        self.at = dict((k, v) for k, v in loc.iteritems() if v != None)

    def __contains__(self, now):
        for k in self.at.keys():
            try:
                if not getattr(now, k) in self.at[k]: return False
            except TypeError:
                if self.at[k] != getattr(now, k): return False
        return True

Count Rows in Doctrine QueryBuilder

It's better to move all logic of working with database to repositores.

So in controller you write

/* you can also inject "FooRepository $repository" using autowire */
$repository = $this->getDoctrine()->getRepository(Foo::class);
$count = $repository->count();

And in Repository/FooRepository.php

public function count()
{
    $qb = $repository->createQueryBuilder('t');
    return $qb
        ->select('count(t.id)')
        ->getQuery()
        ->getSingleScalarResult();
}

It's better to move $qb = ... to separate row in case you want to make complex expressions like

public function count()
{
    $qb = $repository->createQueryBuilder('t');
    return $qb
        ->select('count(t.id)')
        ->where($qb->expr()->isNotNull('t.fieldName'))
        ->andWhere($qb->expr()->orX(
            $qb->expr()->in('t.fieldName2', 0),
            $qb->expr()->isNull('t.fieldName2')
        ))
        ->getQuery()
        ->getSingleScalarResult();
}

Also think about caching your query result - http://symfony.com/doc/current/reference/configuration/doctrine.html#caching-drivers

public function count()
{
    $qb = $repository->createQueryBuilder('t');
    return $qb
        ->select('count(t.id)')
        ->getQuery()
        ->useQueryCache(true)
        ->useResultCache(true, 3600)
        ->getSingleScalarResult();
}

In some simple cases using EXTRA_LAZY entity relations is good
http://doctrine-orm.readthedocs.org/projects/doctrine-orm/en/latest/tutorials/extra-lazy-associations.html

Efficiency of Java "Double Brace Initialization"?

Mario Gleichman describes how to use Java 1.5 generic functions to simulate Scala List literals, though sadly you wind up with immutable Lists.

He defines this class:

package literal;

public class collection {
    public static <T> List<T> List(T...elems){
        return Arrays.asList( elems );
    }
}

and uses it thusly:

import static literal.collection.List;
import static system.io.*;

public class CollectionDemo {
    public void demoList(){
        List<String> slist = List( "a", "b", "c" );
        List<Integer> iList = List( 1, 2, 3 );
        for( String elem : List( "a", "java", "list" ) )
            System.out.println( elem );
    }
}

Google Collections, now part of Guava supports a similar idea for list construction. In this interview, Jared Levy says:

[...] the most heavily-used features, which appear in almost every Java class I write, are static methods that reduce the number of repetitive keystrokes in your Java code. It's so convenient being able to enter commands like the following:

Map<OneClassWithALongName, AnotherClassWithALongName> = Maps.newHashMap();

List<String> animals = Lists.immutableList("cat", "dog", "horse");

7/10/2014: If only it could be as simple as Python's:

animals = ['cat', 'dog', 'horse']

2/21/2020: In Java 11 you can now say:

animals = List.of(“cat”, “dog”, “horse”)

Android Imagebutton change Image OnClick

This misled me a bit - it should be setImageResource instead of setBackgroundResource :) !!

The following works fine :

ImageButton btn = (ImageButton)findViewById(R.id.imageButton1);       
 btn.setImageResource(R.drawable.actions_record);

while when using the setBackgroundResource the actual imagebutton's image stays while the background image is changed which leads to a ugly looking imageButton object

Thanks.

Assign one struct to another in C

Yes, you can assign one instance of a struct to another using a simple assignment statement.

  • In the case of non-pointer or non pointer containing struct members, assignment means copy.

  • In the case of pointer struct members, assignment means pointer will point to the same address of the other pointer.

Let us see this first hand:

#include <stdio.h>

struct Test{
    int foo;
    char *bar;
};

int main(){
    struct Test t1;
    struct Test t2;
    t1.foo = 1;
    t1.bar = malloc(100 * sizeof(char));
    strcpy(t1.bar, "t1 bar value");
    t2.foo = 2;
    t2.bar = malloc(100 * sizeof(char));
    strcpy(t2.bar, "t2 bar value");
    printf("t2 foo and bar before copy: %d %s\n", t2.foo, t2.bar);
    t2 = t1;// <---- ASSIGNMENT
    printf("t2 foo and bar after copy: %d %s\n", t2.foo, t2.bar);
    //The following 3 lines of code demonstrate that foo is deep copied and bar is shallow copied
    strcpy(t1.bar, "t1 bar value changed");
    t1.foo = 3;
    printf("t2 foo and bar after t1 is altered: %d %s\n", t2.foo, t2.bar);
    return 0;
}

Can I redirect the stdout in python into some sort of string buffer?

from cStringIO import StringIO # Python3 use: from io import StringIO
import sys

old_stdout = sys.stdout
sys.stdout = mystdout = StringIO()

# blah blah lots of code ...

sys.stdout = old_stdout

# examine mystdout.getvalue()

Convert nullable bool? to bool

The complete way would be:

bool b1;
bool? b2 = ???;
if (b2.HasValue)
   b1 = b2.Value;

Or you can test for specific values using

bool b3 = (b2 == true); // b2 is true, not false or null

What are all the uses of an underscore in Scala?

From (my entry) in the FAQ, which I certainly do not guarantee to be complete (I added two entries just two days ago):

import scala._    // Wild card -- all of Scala is imported
import scala.{ Predef => _, _ } // Exception, everything except Predef
def f[M[_]]       // Higher kinded type parameter
def f(m: M[_])    // Existential type
_ + _             // Anonymous function placeholder parameter
m _               // Eta expansion of method into method value
m(_)              // Partial function application
_ => 5            // Discarded parameter
case _ =>         // Wild card pattern -- matches anything
val (a, _) = (1, 2) // same thing
for (_ <- 1 to 10)  // same thing
f(xs: _*)         // Sequence xs is passed as multiple parameters to f(ys: T*)
case Seq(xs @ _*) // Identifier xs is bound to the whole matched sequence
var i: Int = _    // Initialization to the default value
def abc_<>!       // An underscore must separate alphanumerics from symbols on identifiers
t._2              // Part of a method name, such as tuple getters
1_000_000         // Numeric literal separator (Scala 2.13+)

This is also part of this question.

How do you import an Eclipse project into Android Studio now?

In newer versions of Android Studio, the best way to bring in an Eclipse/ADT (Android Development Tool) project is to import it directly into Android Studio; we used to recommend you export it from Eclipse to Gradle first, but we haven't been updating ADT often enough to keep pace with Android Studio.

In any event, if you choose "Import Project" from the File menu or from the Welcome screen when you launch Android Studio, it should take you through a specialized wizard that will prompt you that it intends to copy the files into a new directory structure instead of importing them in-place, and it will offer to fix up some common things like converting dependencies into Maven-style includes and such.

It doesn't seem like you're getting this specialized flow. I think it may not be recognizing your imported project as an ADT project, and it's defaulting to the old built-into-IntelliJ behavior which doesn't know about Gradle. To get the specialized import working, the following must be true:

  • The root directory of the project you import must have an AndroidManifest.xml file.
  • Either:
    • The root directory must contain the .project and .classpath files from Eclipse
  • or
    • The root directory must contain res and src directories.

If your project is complex, perhaps you're not pointing it as the root directory it wants to see for the import to succeed.

adding directory to sys.path /PYTHONPATH

As to me, i need to caffe to my python path. I can add it's path to the file /home/xy/.bashrc by add

export PYTHONPATH=/home/xy/caffe-master/python:$PYTHONPATH.

to my /home/xy/.bashrc file.

But when I use pycharm, the path is still not in.

So I can add path to PYTHONPATH variable, by run -> edit Configuration.

enter image description here

Calling a javascript function recursively

You can access the function itself using arguments.callee [MDN]:

if (counter>0) {
    arguments.callee(counter-1);
}

This will break in strict mode, however.

Class Not Found Exception when running JUnit test

For me I had to put the project x/src/test/java/ at the bottom of the "order and export" in the "java build path"

enter image description here

Using LINQ to find item in a List but get "Value cannot be null. Parameter name: source"

Here are more code examples that will produce the argument null exception:

List<Myobj> myList = null;
//from this point on, any linq statement you perform on myList will throw an argument null exception
myList.ToList();
myList.GroupBy(m => m.Id);
myList.Count();
myList.Where(m => m.Id == 0);
myList.Select(m => m.Id == 0);
//etc...

What IDE to use for Python?

Results

Spreadsheet version

spreadsheet screenshot

Alternatively, in plain text: (also available as a a screenshot)

                         Bracket Matching -.  .- Line Numbering
                          Smart Indent -.  |  |  .- UML Editing / Viewing
         Source Control Integration -.  |  |  |  |  .- Code Folding
                    Error Markup -.  |  |  |  |  |  |  .- Code Templates
  Integrated Python Debugging -.  |  |  |  |  |  |  |  |  .- Unit Testing
    Multi-Language Support -.  |  |  |  |  |  |  |  |  |  |  .- GUI Designer (Qt, Eric, etc)
   Auto Code Completion -.  |  |  |  |  |  |  |  |  |  |  |  |  .- Integrated DB Support
     Commercial/Free -.  |  |  |  |  |  |  |  |  |  |  |  |  |  |  .- Refactoring
   Cross Platform -.  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |     
                  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Atom              |Y |F |Y |Y*|Y |Y |Y |Y |Y |Y |  |Y |Y |  |  |  |  |*many plugins
Editra            |Y |F |Y |Y |  |  |Y |Y |Y |Y |  |Y |  |  |  |  |  |
Emacs             |Y |F |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |  |  |  |
Eric Ide          |Y |F |Y |  |Y |Y |  |Y |  |Y |  |Y |  |Y |  |  |  |
Geany             |Y |F |Y*|Y |  |  |  |Y |Y |Y |  |Y |  |  |  |  |  |*very limited
Gedit             |Y |F |Y¹|Y |  |  |  |Y |Y |Y |  |  |Y²|  |  |  |  |¹with plugin; ²sort of
Idle              |Y |F |Y |  |Y |  |  |Y |Y |  |  |  |  |  |  |  |  |
IntelliJ          |Y |CF|Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |
JEdit             |Y |F |  |Y |  |  |  |  |Y |Y |  |Y |  |  |  |  |  |
KDevelop          |Y |F |Y*|Y |  |  |Y |Y |Y |Y |  |Y |  |  |  |  |  |*no type inference
Komodo            |Y |CF|Y |Y |Y |Y |Y |Y |Y |Y |  |Y |Y |Y |  |Y |  |
NetBeans*         |Y |F |Y |Y |Y |  |Y |Y |Y |Y |Y |Y |Y |Y |  |  |Y |*pre-v7.0
Notepad++         |W |F |Y |Y |  |Y*|Y*|Y*|Y |Y |  |Y |Y*|  |  |  |  |*with plugin
Pfaide            |W |C |Y |Y |  |  |  |Y |Y |Y |  |Y |Y |  |  |  |  |
PIDA              |LW|F |Y |Y |  |  |  |Y |Y |Y |  |Y |  |  |  |  |  |VIM based
PTVS              |W |F |Y |Y |Y |Y |Y |Y |Y |Y |  |Y |  |  |Y*|  |Y |*WPF bsed
PyCharm           |Y |CF|Y |Y*|Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |*JavaScript
PyDev (Eclipse)   |Y |F |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |Y |  |  |  |
PyScripter        |W |F |Y |  |Y |Y |  |Y |Y |Y |  |Y |Y |Y |  |  |  |
PythonWin         |W |F |Y |  |Y |  |  |Y |Y |  |  |Y |  |  |  |  |  |
SciTE             |Y |F¹|  |Y |  |Y |  |Y |Y |Y |  |Y |Y |  |  |  |  |¹Mac version is
ScriptDev         |W |C |Y |Y |Y |Y |  |Y |Y |Y |  |Y |Y |  |  |  |  |    commercial
Spyder            |Y |F |Y |  |Y |Y |  |Y |Y |Y |  |  |  |  |  |  |  |
Sublime Text      |Y |CF|Y |Y |  |Y |Y |Y |Y |Y |  |Y |Y |Y*|  |  |  |extensible w/Python,
TextMate          |M |F |  |Y |  |  |Y |Y |Y |Y |  |Y |Y |  |  |  |  |    *PythonTestRunner
UliPad            |Y |F |Y |Y |Y |  |  |Y |Y |  |  |  |Y |Y |  |  |  |
Vim               |Y |F |Y |Y |Y |Y |Y |Y |Y |Y |  |Y |Y |Y |  |  |  |
Visual Studio     |W |CF|Y |Y |Y |Y |Y |Y |Y |Y |? |Y |? |? |Y |? |Y |
Visual Studio Code|Y |F |Y |Y |Y |Y |Y |Y |Y |Y |? |Y |? |? |? |? |Y |uses plugins
WingIde           |Y |C |Y |Y*|Y |Y |Y |Y |Y |Y |  |Y |Y |Y |  |  |  |*support for C
Zeus              |W |C |  |  |  |  |Y |Y |Y |Y |  |Y |Y |  |  |  |  |
                  +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
   Cross Platform -'  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |     
     Commercial/Free -'  |  |  |  |  |  |  |  |  |  |  |  |  |  |  '- Refactoring
   Auto Code Completion -'  |  |  |  |  |  |  |  |  |  |  |  |  '- Integrated DB Support
    Multi-Language Support -'  |  |  |  |  |  |  |  |  |  |  '- GUI Designer (Qt, Eric, etc)
  Integrated Python Debugging -'  |  |  |  |  |  |  |  |  '- Unit Testing
                    Error Markup -'  |  |  |  |  |  |  '- Code Templates
         Source Control Integration -'  |  |  |  |  '- Code Folding
                          Smart Indent -'  |  |  '- UML Editing / Viewing
                         Bracket Matching -'  '- Line Numbering

Acronyms used:

 L  - Linux
 W  - Windows
 M  - Mac
 C  - Commercial
 F  - Free
 CF - Commercial with Free limited edition
 ?  - To be confirmed

I don't mention basics like syntax highlighting as I expect these by default.


This is a just dry list reflecting your feedback and comments, I am not advocating any of these tools. I will keep updating this list as you keep posting your answers.

PS. Can you help me to add features of the above editors to the list (like auto-complete, debugging, etc.)?

We have a comprehensive wiki page for this question https://wiki.python.org/moin/IntegratedDevelopmentEnvironments

Submit edits to the spreadsheet

Nexus 7 (2013) and Win 7 64 - cannot install USB driver despite checking many forums and online resources

SkipSoft.net has some great toolkits. I ran into a similar problem with my Galaxy Nexus.... Ran the corresponding toolkit, which configured my system and downloaded the correct drivers. I then went into Windows Hardware manager after connecting the phone... Windows reported the exclamation that it couldn't find the device driver, so I ran update, and gave it the drivers directory the toolkit had created... and everything started working great. Hope this helps :)

C++ - struct vs. class

POD classes are Plain-Old data classes that have only data members and nothing else. There are a few questions on stackoverflow about the same. Find one here.

Also, you can have functions as members of structs in C++ but not in C. You need to have pointers to functions as members in structs in C.

failed to load ad : 3

My problem was with Payment. I refreshed my payment method and it helped me.

Undoing accidental git stash pop

If your merge was not too complicated another option would be to:

  1. Move all the changes including the merge changes back to stash using "git stash"
  2. Run the merge again and commit your changes (without the changes from the dropped stash)
  3. Run a "git stash pop" which should ignore all the changes from your previous merge since the files are identical now.

After that you are left with only the changes from the stash you dropped too early.

gradle build fails on lint task

You can select proper options from here

android {
    lintOptions {
        // set to true to turn off analysis progress reporting by lint
        quiet true
        // if true, stop the gradle build if errors are found
        abortOnError false
        // if true, only report errors
        ignoreWarnings true
        // if true, emit full/absolute paths to files with errors (true by default)
        //absolutePaths true
        // if true, check all issues, including those that are off by default
        checkAllWarnings true
        // if true, treat all warnings as errors
        warningsAsErrors true
        // turn off checking the given issue id's
        disable 'TypographyFractions','TypographyQuotes'
        // turn on the given issue id's
        enable 'RtlHardcoded','RtlCompat', 'RtlEnabled'
        // check *only* the given issue id's
        check 'NewApi', 'InlinedApi'
        // if true, don't include source code lines in the error output
        noLines true
        // if true, show all locations for an error, do not truncate lists, etc.
        showAll true
        // Fallback lint configuration (default severities, etc.)
        lintConfig file("default-lint.xml")
        // if true, generate a text report of issues (false by default)
        textReport true
        // location to write the output; can be a file or 'stdout'
        textOutput 'stdout'
        // if true, generate an XML report for use by for example Jenkins
        xmlReport false
        // file to write report to (if not specified, defaults to lint-results.xml)
        xmlOutput file("lint-report.xml")
        // if true, generate an HTML report (with issue explanations, sourcecode, etc)
        htmlReport true
        // optional path to report (default will be lint-results.html in the builddir)
        htmlOutput file("lint-report.html")

        // set to true to have all release builds run lint on issues with severity=fatal
        // and abort the build (controlled by abortOnError above) if fatal issues are found
        checkReleaseBuilds true
        // Set the severity of the given issues to fatal (which means they will be
        // checked during release builds (even if the lint target is not included)
        fatal 'NewApi', 'InlineApi'
        // Set the severity of the given issues to error
        error 'Wakelock', 'TextViewEdits'
        // Set the severity of the given issues to warning
        warning 'ResourceAsColor'
        // Set the severity of the given issues to ignore (same as disabling the check)
        ignore 'TypographyQuotes'
    }
}

nuget 'packages' element is not declared warning

The problem is, you need a xsd schema for packages.config.

This is how you can create a schema (I found it here):

Open your Config file -> XML -> Create Schema

enter image description here

This would create a packages.xsd for you, and opens it in Visual Studio:

enter image description here

In my case, packages.xsd was created under this path:

C:\Users\MyUserName\AppData\Local\Temp

Now I don't want to reference the packages.xsd from a Temp folder, but I want it to be added to my solution and added to source control, so other users can get it... so I copied packages.xsd and pasted it into my solution folder. Then I added the file to my solution:

1. Copy packages.xsd in the same folder as your solution

2. From VS, right click on solution -> Add -> Existing Item... and then add packages.xsd

enter image description here

So, now we have created packages.xsd and added it to the Solution. All we need to do is to tell the config file to use this schema.

Open the config file, then from the top menu select:

XML -> Schemas...

Add your packages.xsd, and select Use this schema (see below)

enter image description here

How can I get this ASP.NET MVC SelectList to work?

Building off Thomas Stock's answer, I created these overloaded ToSelectList methods:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web.Mvc;

public static partial class Helpers
{
    public static IEnumerable<SelectListItem> ToSelectList<T>(this IEnumerable<T> enumerable, Func<T, object> value, bool selectAll = false)
    {
        return enumerable.ToSelectList(value, value, selectAll);
    }

    public static IEnumerable<SelectListItem> ToSelectList<T>(this IEnumerable<T> enumerable, Func<T, object> value, object selectedValue)
    {
        return enumerable.ToSelectList(value, value, new List<object>() { selectedValue });
    }

    public static IEnumerable<SelectListItem> ToSelectList<T>(this IEnumerable<T> enumerable, Func<T, object> value, IEnumerable<object> selectedValues)
    {
        return enumerable.ToSelectList(value, value, selectedValues);
    }

    public static IEnumerable<SelectListItem> ToSelectList<T>(this IEnumerable<T> enumerable, Func<T, object> value, Func<T, object> text, bool selectAll = false)
    {
        foreach (var f in enumerable.Where(x => x != null))
        {
            yield return new SelectListItem()
            {
                Value = value(f).ToString(),
                Text = text(f).ToString(),
                Selected = selectAll
            };
        }
    }

    public static IEnumerable<SelectListItem> ToSelectList<T>(this IEnumerable<T> enumerable, Func<T, object> value, Func<T, object> text, object selectedValue)
    {
        return enumerable.ToSelectList(value, text, new List<object>() { selectedValue });
    }

    public static IEnumerable<SelectListItem> ToSelectList<T>(this IEnumerable<T> enumerable, Func<T, object> value, Func<T, object> text, IEnumerable<object> selectedValues)
    {
        var sel = selectedValues != null
            ? selectedValues.Where(x => x != null).ToList().ConvertAll<string>(x => x.ToString())
            : new List<string>();

        foreach (var f in enumerable.Where(x => x != null))
        {
            yield return new SelectListItem()
            {
                Value = value(f).ToString(),
                Text = text(f).ToString(),
                Selected = sel.Contains(value(f).ToString())
            };
        }
    }
}

In your controller, you might do the following:

var pageOptions = new[] { "10", "15", "25", "50", "100", "1000" };
ViewBag.PageOptions = pageOptions.ToSelectList(o => o, "15" /*selectedValue*/);

And finally in your View, put:

@Html.DropDownList("PageOptionsDropDown", ViewBag.PageOptions as IEnumerable<SelectListItem>, "(Select one)")

It will result in the desired output--of course, you can leave out the "(Select one)" optionLabel above if you don't want the first empty item:

<select id="PageOptionsDropDown" name="PageOptionsDropDown">
<option value="">(Select one)</option>
<option value="10">10</option>
<option selected="selected" value="15">15</option>
<option value="25">25</option>
<option value="50">50</option>
<option value="100">100</option>
<option value="1000">1000</option>
</select>

Update: A revised code listing can be found here with XML comments.

Oracle SQL - select within a select (on the same table!)

SELECT eh."Gc_Staff_Number",
       eh."Start_Date",
       MAX(eh2."End_Date") AS "End_Date"
FROM   "Employment_History" eh
LEFT JOIN  "Employment_History" eh2
ON eh."Employee_Number" = eh2."Employee_Number" and eh2."Current_Flag" != 'Y'
WHERE  eh."Current_Flag" = 'Y' 
GROUP BY eh."Gc_Staff_Number",
       eh."Start_Date

R plot: size and resolution

A reproducible example:

the_plot <- function()
{
  x <- seq(0, 1, length.out = 100)
  y <- pbeta(x, 1, 10)
  plot(
    x,
    y,
    xlab = "False Positive Rate",
    ylab = "Average true positive rate",
    type = "l"
  )
}

James's suggestion of using pointsize, in combination with the various cex parameters, can produce reasonable results.

png(
  "test.png",
  width     = 3.25,
  height    = 3.25,
  units     = "in",
  res       = 1200,
  pointsize = 4
)
par(
  mar      = c(5, 5, 2, 2),
  xaxs     = "i",
  yaxs     = "i",
  cex.axis = 2,
  cex.lab  = 2
)
the_plot()
dev.off()

Of course the better solution is to abandon this fiddling with base graphics and use a system that will handle the resolution scaling for you. For example,

library(ggplot2)

ggplot_alternative <- function()
{
  the_data <- data.frame(
    x <- seq(0, 1, length.out = 100),
    y = pbeta(x, 1, 10)
  )

ggplot(the_data, aes(x, y)) +
    geom_line() +
    xlab("False Positive Rate") +
    ylab("Average true positive rate") +
    coord_cartesian(0:1, 0:1)
}

ggsave(
  "ggtest.png",
  ggplot_alternative(),
  width = 3.25,
  height = 3.25,
  dpi = 1200
)

NULL values inside NOT IN clause

The title of this question at the time of writing is

SQL NOT IN constraint and NULL values

From the text of the question it appears that the problem was occurring in a SQL DML SELECT query, rather than a SQL DDL CONSTRAINT.

However, especially given the wording of the title, I want to point out that some statements made here are potentially misleading statements, those along the lines of (paraphrasing)

When the predicate evaluates to UNKNOWN you don't get any rows.

Although this is the case for SQL DML, when considering constraints the effect is different.

Consider this very simple table with two constraints taken directly from the predicates in the question (and addressed in an excellent answer by @Brannon):

DECLARE @T TABLE 
(
 true CHAR(4) DEFAULT 'true' NOT NULL, 
 CHECK ( 3 IN (1, 2, 3, NULL )), 
 CHECK ( 3 NOT IN (1, 2, NULL ))
);

INSERT INTO @T VALUES ('true');

SELECT COUNT(*) AS tally FROM @T;

As per @Brannon's answer, the first constraint (using IN) evaluates to TRUE and the second constraint (using NOT IN) evaluates to UNKNOWN. However, the insert succeeds! Therefore, in this case it is not strictly correct to say, "you don't get any rows" because we have indeed got a row inserted as a result.

The above effect is indeed the correct one as regards the SQL-92 Standard. Compare and contrast the following section from the SQL-92 spec

7.6 where clause

The result of the is a table of those rows of T for which the result of the search condition is true.

4.10 Integrity constraints

A table check constraint is satisfied if and only if the specified search condition is not false for any row of a table.

In other words:

In SQL DML, rows are removed from the result when the WHERE evaluates to UNKNOWN because it does not satisfy the condition "is true".

In SQL DDL (i.e. constraints), rows are not removed from the result when they evaluate to UNKNOWN because it does satisfy the condition "is not false".

Although the effects in SQL DML and SQL DDL respectively may seem contradictory, there is practical reason for giving UNKNOWN results the 'benefit of the doubt' by allowing them to satisfy a constraint (more correctly, allowing them to not fail to satisfy a constraint): without this behaviour, every constraints would have to explicitly handle nulls and that would be very unsatisfactory from a language design perspective (not to mention, a right pain for coders!)

p.s. if you are finding it as challenging to follow such logic as "unknown does not fail to satisfy a constraint" as I am to write it, then consider you can dispense with all this simply by avoiding nullable columns in SQL DDL and anything in SQL DML that produces nulls (e.g. outer joins)!

Import text file as single character string

readChar doesn't have much flexibility so I combined your solutions (readLines and paste).

I have also added a space between each line:

con <- file("/Users/YourtextFile.txt", "r", blocking = FALSE)
singleString <- readLines(con) # empty
singleString <- paste(singleString, sep = " ", collapse = " ")
close(con)

String literals and escape characters in postgresql

Cool.

I also found the documentation regarding the E:

http://www.postgresql.org/docs/8.3/interactive/sql-syntax-lexical.html#SQL-SYNTAX-STRINGS

PostgreSQL also accepts "escape" string constants, which are an extension to the SQL standard. An escape string constant is specified by writing the letter E (upper or lower case) just before the opening single quote, e.g. E'foo'. (When continuing an escape string constant across lines, write E only before the first opening quote.) Within an escape string, a backslash character (\) begins a C-like backslash escape sequence, in which the combination of backslash and following character(s) represents a special byte value. \b is a backspace, \f is a form feed, \n is a newline, \r is a carriage return, \t is a tab. Also supported are \digits, where digits represents an octal byte value, and \xhexdigits, where hexdigits represents a hexadecimal byte value. (It is your responsibility that the byte sequences you create are valid characters in the server character set encoding.) Any other character following a backslash is taken literally. Thus, to include a backslash character, write two backslashes (\\). Also, a single quote can be included in an escape string by writing \', in addition to the normal way of ''.

Efficient thresholding filter of an array with numpy

b = a[a>threshold] this should do

I tested as follows:

import numpy as np, datetime
# array of zeros and ones interleaved
lrg = np.arange(2).reshape((2,-1)).repeat(1000000,-1).flatten()

t0 = datetime.datetime.now()
flt = lrg[lrg==0]
print datetime.datetime.now() - t0

t0 = datetime.datetime.now()
flt = np.array(filter(lambda x:x==0, lrg))
print datetime.datetime.now() - t0

I got

$ python test.py
0:00:00.028000
0:00:02.461000

http://docs.scipy.org/doc/numpy/user/basics.indexing.html#boolean-or-mask-index-arrays

Entity Framework Migrations renaming tables and columns

To expand a bit on Hossein Narimani Rad's answer, you can rename both a table and columns using System.ComponentModel.DataAnnotations.Schema.TableAttribute and System.ComponentModel.DataAnnotations.Schema.ColumnAttribute respectively.

This has a couple benefits:

  1. Not only will this create the the name migrations automatically, but
  2. it will also deliciously delete any foreign keys and recreate them against the new table and column names, giving the foreign keys and constaints proper names.
  3. All this without losing any table data

For example, adding [Table("Staffs")]:

[Table("Staffs")]
public class AccountUser
{
    public long Id { get; set; }

    public long AccountId { get; set; }

    public string ApplicationUserId { get; set; }

    public virtual Account Account { get; set; }

    public virtual ApplicationUser User { get; set; }
}

Will generate the migration:

    protected override void Up(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.DropForeignKey(
            name: "FK_AccountUsers_Accounts_AccountId",
            table: "AccountUsers");

        migrationBuilder.DropForeignKey(
            name: "FK_AccountUsers_AspNetUsers_ApplicationUserId",
            table: "AccountUsers");

        migrationBuilder.DropPrimaryKey(
            name: "PK_AccountUsers",
            table: "AccountUsers");

        migrationBuilder.RenameTable(
            name: "AccountUsers",
            newName: "Staffs");

        migrationBuilder.RenameIndex(
            name: "IX_AccountUsers_ApplicationUserId",
            table: "Staffs",
            newName: "IX_Staffs_ApplicationUserId");

        migrationBuilder.RenameIndex(
            name: "IX_AccountUsers_AccountId",
            table: "Staffs",
            newName: "IX_Staffs_AccountId");

        migrationBuilder.AddPrimaryKey(
            name: "PK_Staffs",
            table: "Staffs",
            column: "Id");

        migrationBuilder.AddForeignKey(
            name: "FK_Staffs_Accounts_AccountId",
            table: "Staffs",
            column: "AccountId",
            principalTable: "Accounts",
            principalColumn: "Id",
            onDelete: ReferentialAction.Cascade);

        migrationBuilder.AddForeignKey(
            name: "FK_Staffs_AspNetUsers_ApplicationUserId",
            table: "Staffs",
            column: "ApplicationUserId",
            principalTable: "AspNetUsers",
            principalColumn: "Id",
            onDelete: ReferentialAction.Restrict);
    }

    protected override void Down(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.DropForeignKey(
            name: "FK_Staffs_Accounts_AccountId",
            table: "Staffs");

        migrationBuilder.DropForeignKey(
            name: "FK_Staffs_AspNetUsers_ApplicationUserId",
            table: "Staffs");

        migrationBuilder.DropPrimaryKey(
            name: "PK_Staffs",
            table: "Staffs");

        migrationBuilder.RenameTable(
            name: "Staffs",
            newName: "AccountUsers");

        migrationBuilder.RenameIndex(
            name: "IX_Staffs_ApplicationUserId",
            table: "AccountUsers",
            newName: "IX_AccountUsers_ApplicationUserId");

        migrationBuilder.RenameIndex(
            name: "IX_Staffs_AccountId",
            table: "AccountUsers",
            newName: "IX_AccountUsers_AccountId");

        migrationBuilder.AddPrimaryKey(
            name: "PK_AccountUsers",
            table: "AccountUsers",
            column: "Id");

        migrationBuilder.AddForeignKey(
            name: "FK_AccountUsers_Accounts_AccountId",
            table: "AccountUsers",
            column: "AccountId",
            principalTable: "Accounts",
            principalColumn: "Id",
            onDelete: ReferentialAction.Cascade);

        migrationBuilder.AddForeignKey(
            name: "FK_AccountUsers_AspNetUsers_ApplicationUserId",
            table: "AccountUsers",
            column: "ApplicationUserId",
            principalTable: "AspNetUsers",
            principalColumn: "Id",
            onDelete: ReferentialAction.Restrict);
    }

Completely remove MariaDB or MySQL from CentOS 7 or RHEL 7

systemd

sudo systemctl stop mysqld.service && sudo yum remove -y mariadb mariadb-server && sudo rm -rf /var/lib/mysql /etc/my.cnf

sysvinit

sudo service mysql stop && sudo apt-get remove mariadb mariadb-server && sudo rm -rf /var/lib/mysql /etc/my.cnf

Error: getaddrinfo ENOTFOUND in nodejs for get call

Struggling for hours, couldn't afford for more.

The solution that worked for me in less than 3 minutes was:

npm install axios

Code ended up even shorter:

const url = `${this.env.someMicroservice.address}/v1/my-end-point`;

const { data } = await axios.get<MyInterface[]>(url, {
  auth: {
    username: this.env.auth.user,
    password: this.env.auth.pass
  }
});

return data;

How do I use installed packages in PyCharm?

Download anaconda https://anaconda.org/

once done installing anaconda...

Go into Settings -> Project Settings -> Project Interpreter.

Then navigate to the "Paths" tab and search for /anaconda/bin/python

click apply

enter image description here

Playing HTML5 video on fullscreen in android webview

Tested on Android 9.0 version

None of the answers worked for me . This is the final thing worked

import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.webkit.WebChromeClient;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.FrameLayout;
import android.widget.ProgressBar;

public class MainActivity extends AppCompatActivity {

    WebView mWebView;


    @SuppressLint("SetJavaScriptEnabled")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        mWebView = (WebView) findViewById(R.id.webView);


        mWebView.setWebViewClient(new WebViewClient());
        mWebView.setWebChromeClient(new MyChrome());
        WebSettings webSettings = mWebView.getSettings();
        webSettings.setJavaScriptEnabled(true);
        webSettings.setAllowFileAccess(true);
        webSettings.setAppCacheEnabled(true);

       if (savedInstanceState == null) {
          mWebView.loadUrl("https://www.youtube.com/");
       }

    }


    private class MyChrome extends WebChromeClient {

        private View mCustomView;
        private WebChromeClient.CustomViewCallback mCustomViewCallback;
        protected FrameLayout mFullscreenContainer;
        private int mOriginalOrientation;
        private int mOriginalSystemUiVisibility;

        MyChrome() {}

        public Bitmap getDefaultVideoPoster()
        {
            if (mCustomView == null) {
                return null;
            }
            return BitmapFactory.decodeResource(getApplicationContext().getResources(), 2130837573);
        }

        public void onHideCustomView()
        {
            ((FrameLayout)getWindow().getDecorView()).removeView(this.mCustomView);
            this.mCustomView = null;
            getWindow().getDecorView().setSystemUiVisibility(this.mOriginalSystemUiVisibility);
            setRequestedOrientation(this.mOriginalOrientation);
            this.mCustomViewCallback.onCustomViewHidden();
            this.mCustomViewCallback = null;
        }

        public void onShowCustomView(View paramView, WebChromeClient.CustomViewCallback paramCustomViewCallback)
        {
            if (this.mCustomView != null)
            {
                onHideCustomView();
                return;
            }
            this.mCustomView = paramView;
            this.mOriginalSystemUiVisibility = getWindow().getDecorView().getSystemUiVisibility();
            this.mOriginalOrientation = getRequestedOrientation();
            this.mCustomViewCallback = paramCustomViewCallback;
            ((FrameLayout)getWindow().getDecorView()).addView(this.mCustomView, new FrameLayout.LayoutParams(-1, -1));
            getWindow().getDecorView().setSystemUiVisibility(3846 | View.SYSTEM_UI_FLAG_LAYOUT_STABLE);
        }
    }

 @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        mWebView.saveState(outState);
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        mWebView.restoreState(savedInstanceState);
    }
}

In AndroidManifest.xml

<activity
  android:name=".MainActivity"
  android:configChanges="orientation|screenSize" />

Source Monster Techno

How to throw a C++ exception

Simple:

#include <stdexcept>

int compare( int a, int b ) {
    if ( a < 0 || b < 0 ) {
        throw std::invalid_argument( "received negative value" );
    }
}

The Standard Library comes with a nice collection of built-in exception objects you can throw. Keep in mind that you should always throw by value and catch by reference:

try {
    compare( -1, 3 );
}
catch( const std::invalid_argument& e ) {
    // do stuff with exception... 
}

You can have multiple catch() statements after each try, so you can handle different exception types separately if you want.

You can also re-throw exceptions:

catch( const std::invalid_argument& e ) {
    // do something

    // let someone higher up the call stack handle it if they want
    throw;
}

And to catch exceptions regardless of type:

catch( ... ) { };

Convert a List<T> into an ObservableCollection<T>

The Observable Collection constructor will take an IList or an IEnumerable.

If you find that you are going to do this a lot you can make a simple extension method:

    public static ObservableCollection<T> ToObservableCollection<T>(this IEnumerable<T> enumerable)
    {
        return new ObservableCollection<T>(enumerable);
    }

Android: How to use webcam in emulator?

I would suggest checking the drivers and updating them if required.

Object variable or With block variable not set (Error 91)

As I wrote in my comment, the solution to your problem is to write the following:

Set hyperLinkText = hprlink.Range

Set is needed because TextRange is a class, so hyperLinkText is an object; as such, if you want to assign it, you need to make it point to the actual object that you need.

How to get textLabel of selected row in swift?

If you want to print the text of a UITableViewCell according to its matching NSIndexPath, you have to use UITableViewDelegate's tableView:didSelectRowAtIndexPath: method and get a reference of the selected UITableViewCell with UITableView's cellForRowAtIndexPath: method.

For example:

import UIKit

class TableViewController: UITableViewController {

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 4
    }

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath)

        switch indexPath.row {
        case 0: cell.textLabel?.text = "Bike"
        case 1: cell.textLabel?.text = "Car"
        case 2: cell.textLabel?.text = "Ball"
        default: cell.textLabel?.text = "Boat"
        }

        return cell
    }

    override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
        let selectedCell = tableView.cellForRowAtIndexPath(indexPath)
        print(selectedCell?.textLabel?.text)
        // this will print Optional("Bike") if indexPath.row == 0
    }

}

However, for many reasons, I would not encourage you to use the previous code. Your UITableViewCell should only be responsible for displaying some content given by a model. In most cases, what you want is to print the content of your model (could be an Array of String) according to a NSIndexPath. By doing things like this, you will separate each element's responsibilities.

Thereby, this is what I would recommend:

import UIKit

class TableViewController: UITableViewController {

    let toysArray = ["Bike", "Car", "Ball", "Boat"]

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return toysArray.count
    }

    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath)
        cell.textLabel?.text = toysArray[indexPath.row]
        return cell
    }

    override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
        let toy = toysArray[indexPath.row]
        print(toy)
        // this will print "Bike" if indexPath.row == 0
    }

}

As you can see, with this code, you don't have to deal with optionals and don't even need to get a reference of the matching UITableViewCell inside tableView:didSelectRowAtIndexPath: in order to print the desired text.

How to dynamically insert a <script> tag via jQuery after page load?

There is one workaround that sounds more like a hack and I agree it's not the most elegant way of doing it, but works 100%:

Say your AJAX response is something like

<b>some html</b>
<script>alert("and some javscript")

Note that I've skipped the closing tag on purpose. Then in the script that loads the above, do the following:

$.ajax({
    url: "path/to/return/the-above-js+html.php",
    success: function(newhtml){
        newhtml += "<";
        newhtml += "/script>";
        $("head").append(newhtml);
    }
});

Just don't ask me why :-) This is one of those things I've come to as a result of desperate almost random trials and fails.

I have no complete suggestions on how it works, but interestingly enough, it will NOT work if you append the closing tag in one line.

In times like these, I feel like I've successfully divided by zero.

All possible array initialization syntaxes

Non-empty arrays

  • var data0 = new int[3]

  • var data1 = new int[3] { 1, 2, 3 }

  • var data2 = new int[] { 1, 2, 3 }

  • var data3 = new[] { 1, 2, 3 }

  • var data4 = { 1, 2, 3 } is not compilable. Use int[] data5 = { 1, 2, 3 } instead.

Empty arrays

  • var data6 = new int[0]
  • var data7 = new int[] { }
  • var data8 = new [] { } and int[] data9 = new [] { } are not compilable.

  • var data10 = { } is not compilable. Use int[] data11 = { } instead.

As an argument of a method

Only expressions that can be assigned with the var keyword can be passed as arguments.

  • Foo(new int[2])
  • Foo(new int[2] { 1, 2 })
  • Foo(new int[] { 1, 2 })
  • Foo(new[] { 1, 2 })
  • Foo({ 1, 2 }) is not compilable
  • Foo(new int[0])
  • Foo(new int[] { })
  • Foo({}) is not compilable

Unable to cast object of type 'System.DBNull' to type 'System.String`

This is the generic method that I use to convert any object that might be a DBNull.Value:

public static T ConvertDBNull<T>(object value, Func<object, T> conversionFunction)
{
    return conversionFunction(value == DBNull.Value ? null : value);
}

usage:

var result = command.ExecuteScalar();

return result.ConvertDBNull(Convert.ToInt32);

shorter:

return command
    .ExecuteScalar()
    .ConvertDBNull(Convert.ToInt32);

CSS Div stretch 100% page height

* {
margin: 0;
}
html, body {
height: 90%;
}
.content {
min-height: 100%;
height: auto !important;
height: 100%;
margin: 0 auto ;
}

Linux Process States

As already explained by others, processes in "D" state (uninterruptible sleep) are responsible for the hang of ps process. To me it has happened many times with RedHat 6.x and automounted NFS home directories.

To list processes in D state you can use the following commands:

cd /proc
for i in [0-9]*;do echo -n "$i :";cat $i/status |grep ^State;done|grep D

To know the current directory of the process and, may be, the mounted NFS disk that has issues you can use a command similar to the following example (replace 31134 with the sleeping process number):

# ls -l /proc/31134/cwd
lrwxrwxrwx 1 pippo users 0 Aug  2 16:25 /proc/31134/cwd -> /auto/pippo

I found that giving the umount command with the -f (force) switch, to the related mounted nfs file system, was able to wake-up the sleeping process:

umount -f /auto/pippo

the file system wasn't unmounted, because it was busy, but the related process did wake-up and I was able to solve the issue without rebooting.

Java: How to get input from System.console()

There are few ways to read input string from your console/keyboard. The following sample code shows how to read a string from the console/keyboard by using Java.

public class ConsoleReadingDemo {

public static void main(String[] args) {

    // ====
    BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
    System.out.print("Please enter user name : ");
    String username = null;
    try {
        username = reader.readLine();
    } catch (IOException e) {
        e.printStackTrace();
    }
    System.out.println("You entered : " + username);

    // ===== In Java 5, Java.util,Scanner is used for this purpose.
    Scanner in = new Scanner(System.in);
    System.out.print("Please enter user name : ");
    username = in.nextLine();      
    System.out.println("You entered : " + username);


    // ====== Java 6
    Console console = System.console();
    username = console.readLine("Please enter user name : ");   
    System.out.println("You entered : " + username);

}
}

The last part of code used java.io.Console class. you can not get Console instance from System.console() when running the demo code through Eclipse. Because eclipse runs your application as a background process and not as a top-level process with a system console.

Best way to do a split pane in HTML

I wanted a vanilla, lightweight (jQuery UI Layout weighs in at 185 KB), no dependency option (all existing libraries require jQuery), so I wrote Split.js.

It weights less than 2 KB and does not require any special markup. It supports older browsers back to Internet Explorer 9 (or Internet Explorer 8 with polyfills). For modern browsers, you can use it with Flexbox and grid layouts.

How can I make the cursor turn to the wait cursor?

Use this with WPF:

Cursor = Cursors.Wait;

// Your Heavy work here

Cursor = Cursors.Arrow;

Animate element transform rotate

Just use CSS transitions:

$(element).css( { transition: "transform 0.5s",
                  transform:  "rotate(" + amount + "deg)" } );

setTimeout( function() { $(element).css( { transition: "none" } ) }, 500 );

As example I set the duration of the animation to 0.5 seconds.

Note the setTimeout to remove the transition css property after the animation is over (500 ms)


For readability I omitted vendor prefixes.

This solution requires browser's transition support off course.

How Does Modulus Divison Work

It's simple, Modulus operator(%) returns remainder after integer division. Let's take the example of your question. How 27 % 16 = 11? When you simply divide 27 by 16 i.e (27/16) then you get remainder as 11, and that is why your answer is 11.

Setting format and value in input type="date"

I think this can help

function myFormatDateFunction(date, format) {
     ...
}

jQuery('input[type="date"]')                                             
    .each(function(){                                                              
        Object.defineProperty(this,'value',{                                         
          get: function() {                                   
            return myFormatDateFunction(this.valueAsDate, 'dd.mm.yyyy');      
          },                                                                         
          configurable: true,                                                        
          enumerable : true                                                          
        });                                                                          
      });                                                                                

how to set auto increment column with sql developer

I found this post, which looks a bit old, but I figured I'd update everyone on my new findings.

I am using Oracle SQL Developer 4.0.2.15 on Windows. Our database is Oracle 10g (version 10.2.0.1) running on Windows.

To make a column auto-increment in Oracle -

  1. Open up the database connection in the Connections tab
  2. Expand the Tables section, and right click the table that has the column you want to change to auto-increment, and select Edit...
  3. Choose the Columns section, and select the column you want to auto-increment (Primary Key column)
  4. Next, click the "Identity Column" section below the list of columns, and change type from None to "Column Sequence"
  5. Leave the default settings (or change the names of the sequence and trigger if you'd prefer) and then click OK

Your id column (primary key) will now auto-increment, but the sequence will be starting at 1. If you need to increment the id to a certain point, you'll have to run a few alter statements against the sequence.
This post has some more details and how to overcome this.

I found the solution here

Delete newline in Vim

Certainly. Vim recognizes the \n character as a newline, so you can just search and replace. In command mode type:

:%s/\n/

How to find text in a column and saving the row number where it is first found - Excel VBA

Alternatively you could use a loop, keep the row number (counter should be the row number) and stop the loop when you find the first "ProjTemp".
Then it should look something like this:

Sub find()
    Dim i As Integer
    Dim firstTime As Integer
    Dim bNotFound As Boolean

    i = 1
    bNotFound = True

      Do While bNotFound
        If Cells(i, 2).Value = "ProjTemp" Then
            firstTime = i
            bNotFound = false
        End If
        i = i + 1
    Loop
End Sub

how to set ASPNETCORE_ENVIRONMENT to be considered for publishing an asp.net core application?

I know this is an old post however thought I'd throw my simple solution into the mix since no one has suggested it.

I use the current directory to determine the current environment then flip the connection string and environment variable. This works great so long as you have a naming convention for your site folders such as test/beta/sandbox.

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        var dir = Environment.CurrentDirectory;
        string connectionString;

        if (dir.Contains("test", StringComparison.OrdinalIgnoreCase))
        {
            connectionString = new ConnectionStringBuilder(server: "xxx", database: "xxx").ConnectionString;
            Environment.SetEnvironmentVariable("ASPNETCORE_ENVIRONMENT", "Development");
        }
        else
        {
            connectionString = new ConnectionStringBuilder(server: "xxx", database: "xxx").ConnectionString;
            Environment.SetEnvironmentVariable("ASPNETCORE_ENVIRONMENT", "Production");
        }

        optionsBuilder.UseSqlServer(connectionString);
        optionsBuilder.UseLazyLoadingProxies();
        optionsBuilder.EnableSensitiveDataLogging();
    }

MySQL select query with multiple conditions

also you can use "AND" instead of "OR" if you want both attributes to be applied.

select * from tickets where (assigned_to='1') and (status='open') order by created_at desc;

Where can I read the Console output in Visual Studio 2015

You can run your program by: Debug -> Start Without Debugging. It will keep a console opened after the program will be finished.

enter image description here

jQuery UI - Draggable is not a function?

4 years after the question got posted, but maybe it will help others who run into this problem. The answer has been posted elsewhere on StackExchange as well, but I lost the link and it's hard to find.

ANSWER: In jQueryTOOLS, the jQuery 'core' is also embedded if you use the default download.

When you load jQuery and jQuery tools, jQuery core gets defined twice and will 'unset' any plugins. 'Draggable' (from jQuery-UI) is such a plug-in.

The solution is to use jQuery tools WITHOUT the jQuery 'core' files and everything will work fine.

auto run a bat script in windows 7 at login

To run the batch file when the VM user logs in:

Drag the shortcut--the one that's currently on your desktop--(or the batch file itself) to Start - All Programs - Startup. Now when you login as that user, it will launch the batch file.

Another way to do the same thing is to save the shortcut or the batch file in %AppData%\Microsoft\Windows\Start Menu\Programs\Startup\.

As far as getting it to run full screen, it depends a bit what you mean. You can have it launch maximized by editing your batch file like this:

start "" /max "C:\Program Files\Oracle\VirtualBox\VirtualBox.exe" --comment "VM" --startvm "12dada4d-9cfd-4aa7-8353-20b4e455b3fa"

But if VirtualBox has a truly full-screen mode (where it hides even the taskbar), you'll have to look for a command-line parameter on VirtualBox.exe. I'm not familiar with that product.

Handling Enter Key in Vue.js

You can also pass events down into child components with something like this:

<CustomComponent
    @keyup.enter="handleKeyUp"
/>

...

<template>
    <div>
        <input
            type="text"
            v-on="$listeners"
        >
    </div>
</template>

<script>
export default {
    name: 'CustomComponent',

    mounted() {
        console.log('listeners', this.$listeners)
    },
}
</script>

That works well if you have a pass-through component and want the listeners to go onto a specific element.

What is a practical, real world example of the Linked List?

He did ask for a practical example; so I'll give it a shot:

Lets say you are writing a firewall; in this firewall you have an IP whitelist and an IP blacklist.

You know that your IP, your jobs IP, and some testing IP's need to be whitelisted. So, you add all of the IP's to the whitelist.

Now, you also have a list of known IP's that should be blocked. So, you add those IPs to the blacklist.

Why might use LinkedList for this?

  1. The operation is fast for adding/removing an item from the list.
  2. You do not know how many IP's are going to blocked/whitelisted. Thus, revealing one of the main advantages to a LinkedList (it's resizable).

Change Color of Fonts in DIV (CSS)

To do links, you can do

.social h2 a:link {
  color: pink;
  font-size: 14px;   
}

You can change the hover, visited, and active link styling too. Just replace "link" with what you want to style. You can learn more at the w3schools page CSS Links.

How to reposition Chrome Developer Tools

As of october 2014, Version 39.0.2171.27 beta (64-bit)

I needed to go in the Chrome Web Developper pan into "Settings" and uncheck Split panels vertically when docked to right

Joda DateTime to Timestamp conversion

Actually this is not a duplicate question. And this how i solve my problem after several times :

   int offset = DateTimeZone.forID("anytimezone").getOffset(new DateTime());

This is the way to get offset from desired timezone.

Let's return to our code, we were getting timestamp from a result set of query, and using it with timezone to create our datetime.

   DateTime dt = new DateTime(rs.getTimestamp("anytimestampcolumn"),
                         DateTimeZone.forID("anytimezone"));

Now we will add our offset to the datetime, and get the timestamp from it.

    dt = dt.plusMillis(offset);
    Timestamp ts = new Timestamp(dt.getMillis());

May be this is not the actual way to get it, but it solves my case. I hope it helps anyone who is stuck here.

How to access private data members outside the class without making "friend"s?

access private members outside class ....only for study purpose .... This program accepts all the below conditions "I dont want to create member function for above class A. And also i dont want to inherit the above class A. I dont want to change the specifier of iData."

//here member function is used only to input and output the private values ... //void hack() is defined outside the class...

//GEEK MODE....;)
#include<iostream.h>
#include<conio.h>

    class A
    {
    private :int iData,x;
    public: void get()             //enter the values
        {cout<<"Enter iData : ";
            cin>>iData;cout<<"Enter x : ";cin>>x;}

        void put()                               //displaying values
    {cout<<endl<<"sum = "<<iData+x;}
};

void hack();        //hacking function

void main()
{A obj;clrscr();
obj.get();obj.put();hack();obj.put();getch();
}

void hack()         //hack begins
{int hck,*ptr=&hck;
cout<<endl<<"Enter value of private data (iData or x) : ";
cin>>hck;     //enter the value assigned for iData or x
for(int i=0;i<5;i++)
{ptr++;
if(*ptr==hck)
{cout<<"Private data hacked...!!!\nChange the value : ";
cin>>*ptr;cout<<hck<<" Is chaged to : "<<*ptr;
return;}
}cout<<"Sorry value not found.....";
}

In Python script, how do I set PYTHONPATH?

PYTHONPATH ends up in sys.path, which you can modify at runtime.

import sys
sys.path += ["whatever"]

Why have header files and .cpp files?

Well, the main reason would be for separating the interface from the implementation. The header declares "what" a class (or whatever is being implemented) will do, while the cpp file defines "how" it will perform those features.

This reduces dependencies so that code that uses the header doesn't necessarily need to know all the details of the implementation and any other classes/headers needed only for that. This will reduce compilation times and also the amount of recompilation needed when something in the implementation changes.

It's not perfect, and you would usually resort to techniques like the Pimpl Idiom to properly separate interface and implementation, but it's a good start.

Disable/turn off inherited CSS3 transitions

Another way to remove all transitions is with the unset keyword:

a.tags {
    transition: unset;
}

In the case of transition, unset is equivalent to initial, since transition is not an inherited property:

a.tags {
    transition: initial;
}

A reader who knows about unset and initial can tell that these solutions are correct immediately, without having to think about the specific syntax of transition.

display:inline vs display:block

Display:block It very much behaves the same way as 'p' tags and it takes up the entire row and there can't be any element next to it until it's floated. Display:inline It's just uses as much space as required and allows other elements to be aligned alongside itself.

Use these properties in case of forms and you will get a better understanding.

ALTER TABLE ADD COLUMN IF NOT EXISTS in SQLite

I took the answer above in C#/.Net, and rewrote it for Qt/C++, not to much changed, but I wanted to leave it here for anyone in the future looking for a C++'ish' answer.

    bool MainWindow::isColumnExisting(QString &table, QString &columnName){

    QSqlQuery q;

    try {
        if(q.exec("PRAGMA table_info("+ table +")"))
            while (q.next()) {
                QString name = q.value("name").toString();     
                if (columnName.toLower() == name.toLower())
                    return true;
            }

    } catch(exception){
        return false;
    }
    return false;
}

How do I get the month and day with leading 0's in SQL? (e.g. 9 => 09)

Use SQL Server's date styles to pre-format your date values.

SELECT
    CONVERT(varchar(2), GETDATE(), 101) AS monthLeadingZero  -- Date Style 101 = mm/dd/yyyy
    ,CONVERT(varchar(2), GETDATE(), 103) AS dayLeadingZero   -- Date Style 103 = dd/mm/yyyy

How to assign Php variable value to Javascript variable?

Put quotes around the <?php echo $cname; ?> to make sure Javascript accepts it as a string, also consider escaping.

What is the difference between WCF and WPF?

Windows Presentation Foundation (WPF)

Next-Generation User Experiences. The Windows Presentation Foundation, WPF, provides a unified framework for building applications and high-fidelity experiences in Windows Vista that blend application UI, documents, and media content. WPF offers developers 2D and 3D graphics support, hardware-accelerated effects, scalability to different form factors, interactive data visualization, and superior content readability.

Windows Communication Foundation (WCF)

Windows Communication Foundation (WCF) is Microsoft’s unified programming model for building service-oriented applications. It enables developers to build secure, reliable, transacted solutions that integrate across platforms and interoperate with existing investments.

How to insert close button in popover for Bootstrap

For me this is the simplest solution to add a close button in a popover.

HTML:

    <button type="button" id="popover" class="btn btn-primary" data-toggle="popover" title="POpover" data-html="true">
                    Show popover
    </button>

    <div id="popover-content" style="display:none"> 
       <!--Your content-->
       <button type="submit" class="btn btn-outline-primary" id="create_btn">Create</button>
       <button type="button" class="btn btn-outline-primary" id="close_popover">Cancel</button>  
    </div>

Javascript:

    document.addEventListener("click",function(e){
        // Close the popover 
        if (e.target.id == "close_popover"){
                $("[data-toggle=popover]").popover('hide');
            }
    });

How to generate a random number in C++?

Here is a simple random generator with approx. equal probability of generating positive and negative values around 0:

  int getNextRandom(const size_t lim) 
  {
        int nextRand = rand() % lim;
        int nextSign = rand() % lim;
        if (nextSign < lim / 2)
            return -nextRand;
        return nextRand;
  }


   int main()
   {
        srand(time(NULL));
        int r = getNextRandom(100);
        cout << r << endl;
        return 0;
   }

Value of type 'T' cannot be converted to

You will also get this error if you have a generic declaration for both your class and your method. For example the code shown below gives this compile error.

public class Foo <T> {

    T var;

    public <T> void doSomething(Class <T> cls) throws InstantiationException, IllegalAccessException {
        this.var = cls.newInstance();
    }

}

This code does compile (note T removed from method declaration):

public class Foo <T> {

    T var;

    public void doSomething(Class <T> cls) throws InstantiationException, IllegalAccessException {
        this.var = cls.newInstance();
    }

}

How to convert a column of DataTable to a List

var list = dataTable.Rows.OfType<DataRow>()
    .Select(dr => dr.Field<string>(columnName)).ToList();

[Edit: Add a reference to System.Data.DataSetExtensions to your project if this does not compile]

jQuery using append with effects

Why don't you simply hide, append, then show, like this:

<div id="parent1" style="  width: 300px; height: 300px; background-color: yellow;">
    <div id="child" style=" width: 100px; height: 100px; background-color: red;"></div>
</div>


<div id="parent2" style="  width: 300px; height: 300px; background-color: green;">
</div>

<input id="mybutton" type="button" value="move">

<script>
    $("#mybutton").click(function(){
        $('#child').hide(1000, function(){
            $('#parent2').append($('#child'));
            $('#child').show(1000);
        });

    });
</script>

Getting number of days in a month

You want DateTime.DaysInMonth:

int days = DateTime.DaysInMonth(year, month);

Obviously it varies by year, as sometimes February has 28 days and sometimes 29. You could always pick a particular year (leap or not) if you want to "fix" it to one value or other.

Repeat String - Javascript

Here's a 5-7% improvement on disfated's answer.

Unroll the loop by stopping at count > 1 and perform an additional result += pattnern concat after the loop. This will avoid the loops final previously unused pattern += pattern without having to use an expensive if-check. The final result would look like this:

String.prototype.repeat = function(count) {
    if (count < 1) return '';
    var result = '', pattern = this.valueOf();
    while (count > 1) {
        if (count & 1) result += pattern;
        count >>= 1, pattern += pattern;
    }
    result += pattern;
    return result;
};

And here's disfated's fiddle forked for the unrolled version: http://jsfiddle.net/wsdfg/

EC2 instance types's exact network performance?

Bandwidth is tiered by instance size, here's a comprehensive answer:

For t2/m3/c3/c4/r3/i2/d2 instances:

  • t2.nano = ??? (Based on the scaling factors, I'd expect 20-30 MBit/s)
  • t2.micro = ~70 MBit/s (qiita says 63 MBit/s) - t1.micro gets about ~100 Mbit/s
  • t2.small = ~125 MBit/s (t2, qiita says 127 MBit/s, cloudharmony says 125 Mbit/s with spikes to 200+ Mbit/s)
  • *.medium = t2.medium gets 250-300 MBit/s, m3.medium ~400 MBit/s
  • *.large = ~450-600 MBit/s (the most variation, see below)
  • *.xlarge = 700-900 MBit/s
  • *.2xlarge = ~1 GBit/s +- 10%
  • *.4xlarge = ~2 GBit/s +- 10%
  • *.8xlarge and marked specialty = 10 Gbit, expect ~8.5 GBit/s, requires enhanced networking & VPC for full throughput

m1 small, medium, and large instances tend to perform higher than expected. c1.medium is another freak, at 800 MBit/s.

I gathered this by combing dozens of sources doing benchmarks (primarily using iPerf & TCP connections). Credit to CloudHarmony & flux7 in particular for many of the benchmarks (note that those two links go to google searches showing the numerous individual benchmarks).

Caveats & Notes:

The large instance size has the most variation reported:

  • m1.large is ~800 Mbit/s (!!!)
  • t2.large = ~500 MBit/s
  • c3.large = ~500-570 Mbit/s (different results from different sources)
  • c4.large = ~520 MBit/s (I've confirmed this independently, by the way)
  • m3.large is better at ~700 MBit/s
  • m4.large is ~445 Mbit/s
  • r3.large is ~390 Mbit/s

Burstable (T2) instances appear to exhibit burstable networking performance too:

  • The CloudHarmony iperf benchmarks show initial transfers start at 1 GBit/s and then gradually drop to the sustained levels above after a few minutes. PDF links to reports below:

  • t2.small (PDF)

  • t2.medium (PDF)
  • t2.large (PDF)

Note that these are within the same region - if you're transferring across regions, real performance may be much slower. Even for the larger instances, I'm seeing numbers of a few hundred MBit/s.

How to have the formatter wrap code with IntelliJ?

Or you can use the shortcut:

Ctrl + Alt + L

Using android.support.v7.widget.CardView in my project (Eclipse)

Maybe it's a little bit late to add answer here. But I think this answer will help the later ones and especially those who don't want to use Android Studio.

Although the documents says that RecyclerView and CardView are part of v7 appcompat library. But as I tried and found, RecyclerView and CardView are actually depend on v7 appcompat library. So if you want to use RecyclerView or CardView, you need to add both v7 appcompat library and RecyclerView/CardView.

Referencing the link here, if you want to use CardView in your Eclipse android project, you need to import both v7 appcompat library and CardView into Eclipse workspace and make them as library projects. Then make CardView project depends on v7 appcompat library project and make your project depends on CardView project.

Doing a join across two databases with different collations on SQL Server and getting an error

You can use the collate clause in a query (I can't find my example right now, so my syntax is probably wrong - I hope it points you in the right direction)

select sone_field collate SQL_Latin1_General_CP850_CI_AI
  from table_1
    inner join table_2
      on (table_1.field collate SQL_Latin1_General_CP850_CI_AI = table_2.field)
  where whatever

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

class foo(object):
    def __str__(self):
        return "representation"
    def __unicode__(self):
        return u"representation"

update to python 3.7 using anaconda

The September 4th release for 3.7 recommends the following:

conda install python=3.7 anaconda=custom

If you want to create a new environment, they recommend:

conda create -n example_env numpy scipy pandas scikit-learn notebook
anaconda-navigator
conda activate example_env

LINQ Contains Case Insensitive

StringComparison.InvariantCultureIgnoreCase just do the job for me:

.Where(fi => fi.DESCRIPTION.Contains(description, StringComparison.InvariantCultureIgnoreCase));

Adding a column to a dataframe in R

Even if that's a 7 years old question, people new to R should consider using the data.table, package.

A data.table is a data.frame so all you can do for/to a data.frame you can also do. But many think are ORDERS of magnitude faster with data.table.

vec <- 1:10
library(data.table)
DT <- data.table(start=c(1,3,5,7), end=c(2,6,7,9))
DT[,new:=apply(DT,1,function(row) mean(vec[ row[1] : row[2] ] ))]

Access Control Request Headers, is added to header in AJAX request with jQuery

And that is why you can't create a bot with JavaScript, because your options are limited to what the browser allows you to do. You can't just order a browser that follows the CORS policy, which most browsers follow, to send random requests to other origins and allow you to get the response that simply!

Additionally, if you tried to edit some request headers manually, like origin-header from the developers tools that come with the browsers, the browser will refuse your edit and may send a preflight OPTIONS request.

T-SQL substring - separating first and last name

For the last name as in US standards (i.e., last word in the [Full Name] column) and considering first name to include a possible middle initial, middle name, etc.:

SELECT DISTINCT
             [Full Name]
            ,REVERSE([Full Name])                   --  to visualize what the formula is doing
            ,CHARINDEX(' ', REVERSE([Full Name]))   --  finds the last space in the string
            ,[Last Name]    =   REVERSE(RTRIM(LTRIM(LEFT(REVERSE([Full Name]), CHARINDEX(' ', REVERSE([Full Name]))))))
            ,[First Name]   =   RTRIM(LTRIM(LEFT([Full Name], LEN([Full Name]) - CHARINDEX(' ', REVERSE([Full Name])))))

FROM ...

Note that this assumes [Full Name] has no spaces before or after the actual string. Otherwise, use RTRIM and LTRIM to remove these.

Left function in c#

It sounds like you're asking about a function

string Left(string s, int left)

that will return the leftmost left characters of the string s. In that case you can just use String.Substring. You can write this as an extension method:

public static class StringExtensions
{
    public static string Left(this string value, int maxLength)
    {
        if (string.IsNullOrEmpty(value)) return value;
        maxLength = Math.Abs(maxLength);

        return ( value.Length <= maxLength 
               ? value 
               : value.Substring(0, maxLength)
               );
    }
}

and use it like so:

string left = s.Left(number);

For your specific example:

string s = fac.GetCachedValue("Auto Print Clinical Warnings").ToLower() + " ";
string left = s.Substring(0, 1);

JSON Naming Convention (snake_case, camelCase or PascalCase)

I think that there isn't a official naming convention to JSON, but you can follow some industry leaders to see how it is working.

Google, which is one of the biggest IT company of the world, has a JSON style guide: https://google.github.io/styleguide/jsoncstyleguide.xml

Taking advantage, you can find other styles guide, which Google defines, here: https://github.com/google/styleguide

Encode a FileStream to base64 with c#

You may try something like that:

    public Stream ConvertToBase64(Stream stream)
    {
        Byte[] inArray = new Byte[(int)stream.Length];
        Char[] outArray = new Char[(int)(stream.Length * 1.34)];
        stream.Read(inArray, 0, (int)stream.Length);
        Convert.ToBase64CharArray(inArray, 0, inArray.Length, outArray, 0);
        return new MemoryStream(Encoding.UTF8.GetBytes(outArray));
    }

Equivalent to 'app.config' for a library (DLL)

Unfortunately, you can only have one app.config file per executable, so if you have DLL’s linked into your application, they cannot have their own app.config files.

Solution is: You don't need to put the App.config file in the Class Library's project.
You put the App.config file in the application that is referencing your class library's dll.

For example, let's say we have a class library named MyClasses.dll which uses the app.config file like so:

string connect = 
ConfigurationSettings.AppSettings["MyClasses.ConnectionString"];

Now, let's say we have an Windows Application named MyApp.exe which references MyClasses.dll. It would contain an App.config with an entry such as:

<appSettings>
    <add key="MyClasses.ConnectionString"
         value="Connection string body goes here" />
</appSettings>

OR

An xml file is best equivalent for app.config. Use xml serialize/deserialize as needed. You can call it what every you want. If your config is "static" and does not need to change, your could also add it to the project as an embedded resource.

Hope it gives some Idea

What is the fastest way to transpose a matrix in C++?

intel mkl suggests in-place and out-of-place transposition/copying matrices. here is the link to the documentation. I would recommend trying out of place implementation as faster ten in-place and into the documentation of the latest version of mkl contains some mistakes.

how to set start page in webconfig file in asp.net c#

If your project contains a RouteConfig.cs file, then you probably need to ignore the route to the root by adding routes.IgnoreRoute(""); in this file.

If it doen't solve your problem, try this :

void Application_BeginRequest(object sender, EventArgs e)
{
    if (Request.AppRelativeCurrentExecutionFilePath == "~/")
        Response.Redirect("~/index.aspx");
}

How to convert a set to a list in python?

Review your first line. Your stack trace is clearly not from the code you've pasted here, so I don't know precisely what you've done.

>>> my_set=([1,2,3,4])
>>> my_set
[1, 2, 3, 4]
>>> type(my_set)
<type 'list'>
>>> list(my_set)
[1, 2, 3, 4]
>>> type(_)
<type 'list'>

What you wanted was set([1, 2, 3, 4]).

>>> my_set = set([1, 2, 3, 4])
>>> my_set
set([1, 2, 3, 4])
>>> type(my_set)
<type 'set'>
>>> list(my_set)
[1, 2, 3, 4]
>>> type(_)
<type 'list'>

The "not callable" exception means you were doing something like set()() - attempting to call a set instance.

How to work with string fields in a C struct?

You could just use an even simpler typedef:

typedef char *string;

Then, your malloc would look like a usual malloc:

string s = malloc(maxStringLength);

This version of Android Studio cannot open this project, please retry with Android Studio 3.4 or newer

This issue arises due to updates, You can resolve this by downgrading the gradle used from com.android.tools.build:gradle:3.2.1 to a previous gradle like com.android.tools.build:gradle:3.0.0 or anything older than the current one

How to delete an item in a list if it exists?

If index doesn't find the searched string, it throws the ValueError you're seeing. Either catch the ValueError:

try:
    i = s.index("")
    del s[i]
except ValueError:
    print "new_tag_list has no empty string"

or use find, which returns -1 in that case.

i = s.find("")
if i >= 0:
    del s[i]
else:
    print "new_tag_list has no empty string"

HTML 5 video or audio playlist

Yep, you can simply point your src tag to a .m3u playlist file. A .m3u file is easy to construct -

#hosted mp3's need absolute paths but file system links can use relative paths
http://servername.com/path/to/mp3.mp3
http://servername.com/path/to/anothermp3.mp3
/path/to/local-mp3.mp3

-----UPDATE-----

Well, it turns out playlist m3u files are supported on the iPhone, but not on much else including Safari 5 which is kind of sad. I'm not sure about Android phones but I doubt they support it either since Chrome doesn't. Sorry for the misinformation.

Node Version Manager install - nvm command not found

For Mac OS:

  1. Open Terminal
  2. Run touch ~/.bash_profile
  3. Run vi ~/.bash_profile
  4. Type source ~/.nvm/nvm.sh
  5. Press Shift + Esc and type wq and press enter
  6. Done.

Statically rotate font-awesome icons

Before FontAwesome 5:

The standard declarations just contain .fa-rotate-90, .fa-rotate-180 and .fa-rotate-270. However you can easily create your own:

.fa-rotate-45 {
    -webkit-transform: rotate(45deg);
    -moz-transform: rotate(45deg);
    -ms-transform: rotate(45deg);
    -o-transform: rotate(45deg);
    transform: rotate(45deg);
}

With FontAwesome 5:

You can use what’s so called “Power Transforms”. Example:

<i class="fas fa-snowman" data-fa-transform="rotate-90"></i>
<i class="fas fa-snowman" data-fa-transform="rotate-180"></i>
<i class="fas fa-snowman" data-fa-transform="rotate-270"></i>
<i class="fas fa-snowman" data-fa-transform="rotate-30"></i>
<i class="fas fa-snowman" data-fa-transform="rotate--30"></i>

You need to add the data-fa-transform attribute with the value of rotate- and your desired rotation in degrees.

Source: https://fontawesome.com/how-to-use/on-the-web/styling/power-transforms

IF formula to compare a date with current date and return result

I think this will cover any possible scenario for what is in O10:

=IF(ISBLANK(O10),"",IF(O10<TODAY(),IF(TODAY()-O10<>1,CONCATENATE("Due in ",TEXT(TODAY()-O10,"d")," days"),CONCATENATE("Due in ",TEXT(TODAY()-O10,"d")," day")),IF(O10=TODAY(),"Due Today","Overdue")))

For Dates that are before Today, it will tell you how many days the item is due in. If O10 = Today then it will say "Due Today". Anything past Today and it will read overdue. Lastly, if it is blank, the cell will also appear blank. Let me know what you think!

javascript regex for special characters

this is the actual regex only match:

/[-!$%^&*()_+|~=`{}[:;<>?,.@#\]]/g

Content type 'application/x-www-form-urlencoded;charset=UTF-8' not supported for @RequestBody MultiValueMap

In Spring 5

@PostMapping( "some/request/path" )
public void someControllerMethod( @RequestParam MultiValueMap body ) {

    // import org.springframework.util.MultiValueMap;

    String datax = (String) body .getFirst("datax");
}

Check if table exists

Adding to Gaby's post, my jdbc getTables() for Oracle 10g requires all caps to work:

"employee" -> "EMPLOYEE"

Otherwise I would get an exception:

java.sql.SqlExcepcion exhausted resultset

(even though "employee" is in the schema)

Spark DataFrame groupBy and sort in the descending order (pyspark)

In pyspark 2.4.4

1) group_by_dataframe.count().filter("`count` >= 10").orderBy('count', ascending=False)

2) from pyspark.sql.functions import desc
   group_by_dataframe.count().filter("`count` >= 10").orderBy('count').sort(desc('count'))

No need to import in 1) and 1) is short & easy to read,
So I prefer 1) over 2)

How to use querySelectorAll only for elements that have a specific attribute set?

You can use querySelectorAll() like this:

var test = document.querySelectorAll('input[value][type="checkbox"]:not([value=""])');

This translates to:

get all inputs with the attribute "value" and has the attribute "value" that is not blank.

In this demo, it disables the checkbox with a non-blank value.

Laravel Request::all() Should Not Be Called Statically

use Illuminate\Http\Request;
public function store(Request $request){
   dd($request->all());
}

is same in context saying

use Request;
public function store(){
   dd(Request::all());
}

port 8080 is already in use and no process using 8080 has been listed

In windows " wmic process where processid="pid of the process running" get commandline " worked for me. The culprit was wrapper.exe process of webhuddle jboss soft.

Excel CSV - Number cell format

Load csv into oleDB and force all inferred datatypes to string

i asked the same question and then answerd it with code.

basically when the csv file is loaded the oledb driver makes assumptions, you can tell it what assumptions to make.

My code forces all datatypes to string though ... its very easy to change the schema. for my purposes i used an xslt to get ti the way i wanted - but i am parsing a wide variety of files.

Trigger insert old values- values that was updated

ALTER trigger ETU on Employee FOR UPDATE AS insert into Log (EmployeeId, LogDate, OldName) select EmployeeId, getdate(), name from deleted go

How to extract public key using OpenSSL?

openssl rsa -in privkey.pem -pubout > key.pub

That writes the public key to key.pub

Find unique rows in numpy.array

np.unique works by sorting a flattened array, then looking at whether each item is equal to the previous. This can be done manually without flattening:

ind = np.lexsort(a.T)
a[ind[np.concatenate(([True],np.any(a[ind[1:]]!=a[ind[:-1]],axis=1)))]]

This method does not use tuples, and should be much faster and simpler than other methods given here.

NOTE: A previous version of this did not have the ind right after a[, which mean that the wrong indices were used. Also, Joe Kington makes a good point that this does make a variety of intermediate copies. The following method makes fewer, by making a sorted copy and then using views of it:

b = a[np.lexsort(a.T)]
b[np.concatenate(([True], np.any(b[1:] != b[:-1],axis=1)))]

This is faster and uses less memory.

Also, if you want to find unique rows in an ndarray regardless of how many dimensions are in the array, the following will work:

b = a[lexsort(a.reshape((a.shape[0],-1)).T)];
b[np.concatenate(([True], np.any(b[1:]!=b[:-1],axis=tuple(range(1,a.ndim)))))]

An interesting remaining issue would be if you wanted to sort/unique along an arbitrary axis of an arbitrary-dimension array, something that would be more difficult.

Edit:

To demonstrate the speed differences, I ran a few tests in ipython of the three different methods described in the answers. With your exact a, there isn't too much of a difference, though this version is a bit faster:

In [87]: %timeit unique(a.view(dtype)).view('<i8')
10000 loops, best of 3: 48.4 us per loop

In [88]: %timeit ind = np.lexsort(a.T); a[np.concatenate(([True], np.any(a[ind[1:]]!= a[ind[:-1]], axis=1)))]
10000 loops, best of 3: 37.6 us per loop

In [89]: %timeit b = [tuple(row) for row in a]; np.unique(b)
10000 loops, best of 3: 41.6 us per loop

With a larger a, however, this version ends up being much, much faster:

In [96]: a = np.random.randint(0,2,size=(10000,6))

In [97]: %timeit unique(a.view(dtype)).view('<i8')
10 loops, best of 3: 24.4 ms per loop

In [98]: %timeit b = [tuple(row) for row in a]; np.unique(b)
10 loops, best of 3: 28.2 ms per loop

In [99]: %timeit ind = np.lexsort(a.T); a[np.concatenate(([True],np.any(a[ind[1:]]!= a[ind[:-1]],axis=1)))]
100 loops, best of 3: 3.25 ms per loop

C++11 thread-safe queue

I would rewrite your dequeue function as:

std::string FileQueue::dequeue(const std::chrono::milliseconds& timeout)
{
    std::unique_lock<std::mutex> lock(qMutex);
    while(q.empty()) {
        if (populatedNotifier.wait_for(lock, timeout) == std::cv_status::timeout ) 
           return std::string();
    }
    std::string ret = q.front();
    q.pop();
    return ret;
}

It is shorter and does not have duplicate code like your did. Only issue it may wait longer that timeout. To prevent that you would need to remember start time before loop, check for timeout and adjust wait time accordingly. Or specify absolute time on wait condition.

angularjs: ng-src equivalent for background-image:url(...)

This one works for me

<li ng-style="{'background-image':'url(/static/'+imgURL+')'}">...</li>

Appending to 2D lists in Python

[[]]*3 is not the same as [[], [], []].

It's as if you'd said

a = []
listy = [a, a, a]

In other words, all three list references refer to the same list instance.

How to update nested state properties in React

stateUpdate = () => {
    let obj = this.state;
    if(this.props.v12_data.values.email) {
      obj.obj_v12.Customer.EmailAddress = this.props.v12_data.values.email
    }
    this.setState(obj)
}

Create an Android GPS tracking application

Basically you need following things to make location detector android app

Now if you write each of these module yourself then it needs much time and efforts. So it would be better to use ready resources that are being maintained already.

Using all these resources, you will be able to create an flawless android location detection app.

1. Location Listening

You will first need to listen for current location of user. You can use any of below libraries to quick start.

Google Play Location Samples

This library provide last known location, location updates

Location Manager

With this library you just need to provide a Configuration object with your requirements, and you will receive a location or a fail reason with all the stuff are described above handled.

Live Location Sharing

Use this open source repo of the Hypertrack Live app to build live location sharing experience within your app within a few hours. HyperTrack Live app helps you share your Live Location with friends and family through your favorite messaging app when you are on the way to meet up. HyperTrack Live uses HyperTrack APIs and SDKs.

2. Markers Library

Google Maps Android API utility library

  • Marker clustering — handles the display of a large number of points
  • Heat maps — display a large number of points as a heat map
  • IconGenerator — display text on your Markers
  • Poly decoding and encoding — compact encoding for paths, interoperability with Maps API web services
  • Spherical geometry — for example: computeDistance, computeHeading, computeArea
  • KML — displays KML data
  • GeoJSON — displays and styles GeoJSON data

3. Polyline Libraries

DrawRouteMaps

If you want to add route maps feature in your apps you can use DrawRouteMaps to make you work more easier. This is lib will help you to draw route maps between two point LatLng.

trail-android

Simple, smooth animation for route / polylines on google maps using projections. (WIP)

Google-Directions-Android

This project allows you to calculate the direction between two locations and display the route on a Google Map using the Google Directions API.

A map demo app for quick start with maps

JavaScript code to stop form submission

Lets say you have a form similar to this

<form action="membersDeleteAllData.html" method="post">
    <button type="submit" id="btnLoad" onclick="confirmAction(event);">ERASE ALL DATA</button>
</form>

Here is the javascript for the confirmAction function

<script type="text/javascript">
    function confirmAction(e)
    {
        var confirmation = confirm("Are you sure about this ?") ;

        if (!confirmation)
        {
            e.preventDefault() ;
            returnToPreviousPage();
        }

        return confirmation ;
    }
</script>

This one works on Firefox, Chrome, Internet Explorer(edge), Safari, etc.

If that is not the case let me know

How to display a confirmation dialog when clicking an <a> link?

I'd suggest avoiding in-line JavaScript:

var aElems = document.getElementsByTagName('a');

for (var i = 0, len = aElems.length; i < len; i++) {
    aElems[i].onclick = function() {
        var check = confirm("Are you sure you want to leave?");
        if (check == true) {
            return true;
        }
        else {
            return false;
        }
    };
}?

JS Fiddle demo.

The above updated to reduce space, though maintaining clarity/function:

var aElems = document.getElementsByTagName('a');

for (var i = 0, len = aElems.length; i < len; i++) {
    aElems[i].onclick = function() {
        return confirm("Are you sure you want to leave?");
    };
}

JS Fiddle demo.

A somewhat belated update, to use addEventListener() (as suggested, by bažmegakapa, in the comments below):

function reallySure (event) {
    var message = 'Are you sure about that?';
    action = confirm(message) ? true : event.preventDefault();
}
var aElems = document.getElementsByTagName('a');

for (var i = 0, len = aElems.length; i < len; i++) {
    aElems[i].addEventListener('click', reallySure);
}

JS Fiddle demo.

The above binds a function to the event of each individual link; which is potentially quite wasteful, when you could bind the event-handling (using delegation) to an ancestor element, such as the following:

function reallySure (event) {
    var message = 'Are you sure about that?';
    action = confirm(message) ? true : event.preventDefault();
}

function actionToFunction (event) {
    switch (event.target.tagName.toLowerCase()) {
        case 'a' :
            reallySure(event);
            break;
        default:
            break;
    }
}

document.body.addEventListener('click', actionToFunction);

JS Fiddle demo.

Because the event-handling is attached to the body element, which normally contains a host of other, clickable, elements I've used an interim function (actionToFunction) to determine what to do with that click. If the clicked element is a link, and therefore has a tagName of a, the click-handling is passed to the reallySure() function.

References:

What does "SyntaxError: Missing parentheses in call to 'print'" mean in Python?

Unfortunately, the old xkcd comic isn't completely up to date anymore.

https://imgs.xkcd.com/comics/python.png

Since Python 3.0 you have to write:

print("Hello, World!")

And someone has still to write that antigravity library :(

Java LinkedHashMap get first or last entry

Yea I came across the same problem, but luckily I only need the first element... - This is what I did for it.

private String getDefaultPlayerType()
{
    String defaultPlayerType = "";
    for(LinkedHashMap.Entry<String,Integer> entry : getLeagueByName(currentLeague).getStatisticsOrder().entrySet())
    {
        defaultPlayerType = entry.getKey();
        break;
    }
    return defaultPlayerType;
}

If you need the last element as well - I'd look into how to reverse the order of your map - store it in a temp variable, access the first element in the reversed map(therefore it would be your last element), kill the temp variable.

Here's some good answers on how to reverse order a hashmap:

How to iterate hashmap in reverse order in Java

If you use help from the above link, please give them up-votes :) Hope this can help someone.

In ASP.NET, when should I use Session.Clear() rather than Session.Abandon()?

Session.Abandon() destroys the session and the Session_OnEnd event is triggered.

Session.Clear() just removes all values (content) from the Object. The session with the same key is still alive.

So, if you use Session.Abandon(), you lose that specific session and the user will get a new session key. You could use it for example when the user logs out.

Use Session.Clear(), if you want that the user remaining in the same session (if you don't want the user to relogin for example) and reset all the session specific data.

How to implement class constants?

For me none of earlier answer works. I did need to convert my static class to enum. Like this:

export enum MyConstants {
  MyFirstConstant = 'MyFirstConstant',
  MySecondConstant = 'MySecondConstant'
}

Then in my component I add new property as suggested in other answers

export class MyComponent {
public MY_CONTANTS = MyConstans;
constructor() { }
}

Then in my component's template I use it this way

<div [myDirective]="MY_CONTANTS.MyFirstConstant"> </div>

EDIT: Sorry. My problem was different than OP's. I still leave this here if someelse have same problem than I.

Jenkins: Can comments be added to a Jenkinsfile?

Comments work fine in any of the usual Java/Groovy forms, but you can't currently use groovydoc to process your Jenkinsfile (s).

First, groovydoc chokes on files without extensions with the wonderful error

java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.codehaus.groovy.tools.GroovyStarter.rootLoader(GroovyStarter.java:109)
    at org.codehaus.groovy.tools.GroovyStarter.main(GroovyStarter.java:131)
Caused by: java.lang.StringIndexOutOfBoundsException: String index out of range: -1
    at java.lang.String.substring(String.java:1967)
    at org.codehaus.groovy.tools.groovydoc.SimpleGroovyClassDocAssembler.<init>(SimpleGroovyClassDocAssembler.java:67)
    at org.codehaus.groovy.tools.groovydoc.GroovyRootDocBuilder.parseGroovy(GroovyRootDocBuilder.java:131)
    at org.codehaus.groovy.tools.groovydoc.GroovyRootDocBuilder.getClassDocsFromSingleSource(GroovyRootDocBuilder.java:83)
    at org.codehaus.groovy.tools.groovydoc.GroovyRootDocBuilder.processFile(GroovyRootDocBuilder.java:213)
    at org.codehaus.groovy.tools.groovydoc.GroovyRootDocBuilder.buildTree(GroovyRootDocBuilder.java:168)
    at org.codehaus.groovy.tools.groovydoc.GroovyDocTool.add(GroovyDocTool.java:82)
    at org.codehaus.groovy.tools.groovydoc.GroovyDocTool$add.call(Unknown Source)
    at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:48)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:113)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:125)
    at org.codehaus.groovy.tools.groovydoc.Main.execute(Main.groovy:214)
    at org.codehaus.groovy.tools.groovydoc.Main.main(Main.groovy:180)
    ... 6 more

... and second, as far as I can tell Javadoc-style commments at the start of a groovy script are ignored. So even if you copy/rename your Jenkinsfile to Jenkinsfile.groovy, you won't get much useful output.

I want to be able to use a

/**
 * Document my Jenkinsfile's overall purpose here
 */

comment at the start of my Jenkinsfile. No such luck (yet).

groovydoc will process classes and methods defined in your Jenkinsfile if you pass -private to the command, though.

Left Join With Where Clause

You might find it easier to understand by using a simple subquery

SELECT `settings`.*, (
    SELECT `value` FROM `character_settings`
    WHERE `character_settings`.`setting_id` = `settings`.`id`
      AND `character_settings`.`character_id` = '1') AS cv_value
FROM `settings`

The subquery is allowed to return null, so you don't have to worry about JOIN/WHERE in the main query.

Sometimes, this works faster in MySQL, but compare it against the LEFT JOIN form to see what works best for you.

SELECT s.*, c.value
FROM settings s
LEFT JOIN character_settings c ON c.setting_id = s.id AND c.character_id = '1'

How to run Linux commands in Java?

try to use unix4j. it s about a library in java to run linux command. for instance if you got a command like: cat test.txt | grep "Tuesday" | sed "s/kilogram/kg/g" | sort in this program will become: Unix4j.cat("test.txt").grep("Tuesday").sed("s/kilogram/kg/g").sort();

Append a dictionary to a dictionary

A three-liner to combine or merge two dictionaries:

dest = {}
dest.update(orig)
dest.update(extra)

This creates a new dictionary dest without modifying orig and extra.

Note: If a key has different values in orig and extra, then extra overrides orig.

Apache gives me 403 Access Forbidden when DocumentRoot points to two different drives

For Apache 2.4.2: I was getting 403: Forbidden continuously when I was trying to access WAMP on my Windows 7 desktop from my iPhone on WiFi. On one blog, I found the solution - add Require all granted after Allow all in the <Directory> section. So this is how my <Directory> section looks like inside <VirtualHost>

<Directory "C:/wamp/www">
    Options Indexes FollowSymLinks MultiViews Includes ExecCGI
    AllowOverride All
    Order Allow,Deny
    Allow from all
    Require all granted
</Directory>

Declare and Initialize String Array in VBA

The problem here is that the length of your array is undefined, and this confuses VBA if the array is explicitly defined as a string. Variants, however, seem to be able to resize as needed (because they hog a bunch of memory, and people generally avoid them for a bunch of reasons).

The following code works just fine, but it's a bit manual compared to some of the other languages out there:

Dim SomeArray(3) As String

SomeArray(0) = "Zero"
SomeArray(1) = "One"
SomeArray(2) = "Two"
SomeArray(3) = "Three"

How can I get a vertical scrollbar in my ListBox?

The problem with your solution is you're putting a scrollbar around a ListBox where you probably want to put it inside the ListBox.

If you want to force a scrollbar in your ListBox, use the ScrollBar.VerticalScrollBarVisibility attached property.

<ListBox 
    ItemsSource="{Binding}" 
    ScrollViewer.VerticalScrollBarVisibility="Visible">
</ListBox>

Setting this value to Auto will popup the scrollbar on an as needed basis.

How do I get only directories using Get-ChildItem?

Use:

Get-ChildItem \\myserver\myshare\myshare\ -Directory | Select-Object -Property name |  convertto-csv -NoTypeInformation  | Out-File c:\temp\mydirectorylist.csv

Which does the following

  • Get a list of directories in the target location: Get-ChildItem \\myserver\myshare\myshare\ -Directory
  • Extract only the name of the directories: Select-Object -Property name
  • Convert the output to CSV format: convertto-csv -NoTypeInformation
  • Save the result to a file: Out-File c:\temp\mydirectorylist.csv

Javascript event handler with parameters

Short answer:

x.addEventListener("click", function(e){myfunction(e, param1, param2)});

... 

function myfunction(e, param1, param1) {
    ... 
} 

Difference between scaling horizontally and vertically for databases

Yes scaling horizontally means adding more machines, but it also implies that the machines are equal in the cluster. MySQL can scale horizontally in terms of Reading data, through the use of replicas, but once it reaches capacity of the server mem/disk, you have to begin sharding data across servers. This becomes increasingly more complex. Often keeping data consistent across replicas is a problem as replication rates are often too slow to keep up with data change rates.

Couchbase is also a fantastic NoSQL Horizontal Scaling database, used in many commercial high availability applications and games and arguably the highest performer in the category. It partitions data automatically across cluster, adding nodes is simple, and you can use commodity hardware, cheaper vm instances (using Large instead of High Mem, High Disk machines at AWS for instance). It is built off the Membase (Memcached) but adds persistence. Also, in the case of Couchbase, every node can do reads and writes, and are equals in the cluster, with only failover replication (not full dataset replication across all servers like in mySQL).

Performance-wise, you can see an excellent Cisco benchmark: http://blog.couchbase.com/understanding-performance-benchmark-published-cisco-and-solarflare-using-couchbase-server

Here is a great blog post about Couchbase Architecture: http://horicky.blogspot.com/2012/07/couchbase-architecture.html

How do I use the CONCAT function in SQL Server 2008 R2?

Yes the function is not in sql 2008. You can use the cast operation to do that.

For example we have employee table and you want name with applydate.

so you can use

Select   cast(name as varchar) + cast(applydate as varchar) from employee

It will work where concat function is not working.

Package php5 have no installation candidate (Ubuntu 16.04)

Currently, I am using Ubuntu 16.04 LTS. Me too was facing same problem while Fetching the Postgress Database values using Php so i resolved it by using the below commands.

Mine PHP version is 7.0, so i tried the below command.

apt-get install php-pgsql

Remember to restart Apache.

/etc/init.d/apache2 restart

Mysql adding user for remote access

In order to connect remotely you have to have MySQL bind port 3306 to your machine's IP address in my.cnf. Then you have to have created the user in both localhost and '%' wildcard and grant permissions on all DB's as such . See below:

my.cnf (my.ini on windows)

#Replace xxx with your IP Address 
bind-address        = xxx.xxx.xxx.xxx

then

CREATE USER 'myuser'@'localhost' IDENTIFIED BY 'mypass';
CREATE USER 'myuser'@'%' IDENTIFIED BY 'mypass';

Then

GRANT ALL ON *.* TO 'myuser'@'localhost';
GRANT ALL ON *.* TO 'myuser'@'%';
flush privileges;

Depending on your OS you may have to open port 3306 to allow remote connections.

Excel how to fill all selected blank cells with text

I don't believe search and replace will do it for you (doesn't work for me in Excel 2010 Home). Are you sure you want to put "null" in EVERY cell in the sheet? That is millions of cells, in which case there is no way a search and replace would be able to handle it memory-wise (correct me if I am wrong).

In the case I am right and you don't want millions of "null" cells, then here is a macro. It asks you to select the range then put "null" inside every cell that was blank.

Sub FillWithNull()

Dim cell As range
Dim myRange As range

Set myRange = Application.InputBox("Select the range", Type:=8)
Application.ScreenUpdating = False

For Each cell In myRange
    If Len(cell) = 0 Then
        cell.Value = "Null"
    End If
Next

Application.ScreenUpdating = True

End Sub

Plotting categorical data with pandas and matplotlib

You could also use countplot from seaborn. This package builds on pandas to create a high level plotting interface. It gives you good styling and correct axis labels for free.

import pandas as pd
import seaborn as sns
sns.set()

df = pd.DataFrame({'colour': ['red', 'blue', 'green', 'red', 'red', 'yellow', 'blue'],
                   'direction': ['up', 'up', 'down', 'left', 'right', 'down', 'down']})
sns.countplot(df['colour'], color='gray')

enter image description here

It also supports coloring the bars in the right color with a little trick

sns.countplot(df['colour'],
              palette={color: color for color in df['colour'].unique()})

enter image description here