Programs & Examples On #Gwt animation

Deals with animations of widgets in GWT using the com.google.gwt.animation.client.Animation or some custom techniques.

How to start a background process in Python?

Use subprocess.Popen() with the close_fds=True parameter, which will allow the spawned subprocess to be detached from the Python process itself and continue running even after Python exits.

https://gist.github.com/yinjimmy/d6ad0742d03d54518e9f

import os, time, sys, subprocess

if len(sys.argv) == 2:
    time.sleep(5)
    print 'track end'
    if sys.platform == 'darwin':
        subprocess.Popen(['say', 'hello'])
else:
    print 'main begin'
    subprocess.Popen(['python', os.path.realpath(__file__), '0'], close_fds=True)
    print 'main end'

Get the year from specified date php

$Y_date = split("-","2068-06-15");
$year = $Y_date[0];

You can use explode also

What is /var/www/html?

In the most shared hosts you can't set it.

On a VPS or dedicated server, you can set it, but everything has its price.

On shared hosts, in general you receive a Linux account, something such as /home/(your username)/, and the equivalent of /var/www/html turns to /home/(your username)/public_html/ (or something similar, such as /home/(your username)/www)

If you're accessing your account via FTP, you automatically has accessing the your */home/(your username)/ folder, just find the www or public_html and put your site in it.

If you're using absolute path in the code, bad news, you need to refactor it to use relative paths in the code, at least in a shared host.

Creating a directory in /sdcard fails

File f = new File(Environment.getExternalStorageDirectory().getAbsolutePath()
        + "/FoderName");
if (!f.exists()) {
    f.mkdirs();
}

Android Emulator: Installation error: INSTALL_FAILED_VERSION_DOWNGRADE

Just uninstall the previous Apk and install the updated APK

NoSql vs Relational database

NOSQL has no special advantages over the relational database model. NOSQL does address certain limitations of current SQL DBMSs but it doesn't imply any fundamentally new capabilities over previous data models.

NOSQL means only no SQL (or "not only SQL") but that doesn't mean the same as no relational. A relational database in principle would make a very good NOSQL solution - it's just that none of the current set of NOSQL products uses the relational model.

Can you delete multiple branches in one command with Git?

If you have installed Git GUI, which is a default add-on for Windows, then it's the simplest. You can use ctrl to choose multiple branches and delete them with one click.

Is it possible in Java to check if objects fields are null and then add default value to all those attributes?

I tried this and it works without any issues to validate if the field is empty. I have answered your question partially as I haven't personally tried to add default values to attributes

if(field.getText()!= null && !field.getText().isEmpty())

Hope it helps

Why do table names in SQL Server start with "dbo"?

If you are using Sql Server Management Studio, you can create your own schema by browsing to Databases - Your Database - Security - Schemas.

To create one using a script is as easy as (for example):

CREATE SCHEMA [EnterSchemaNameHere] AUTHORIZATION [dbo]

You can use them to logically group your tables, for example by creating a schema for "Financial" information and another for "Personal" data. Your tables would then display as:

Financial.BankAccounts Financial.Transactions Personal.Address

Rather than using the default schema of dbo.

How to include "zero" / "0" results in COUNT aggregate?

You must use LEFT JOIN instead of INNER JOIN

SELECT person.person_id, COUNT(appointment.person_id) AS "number_of_appointments"
FROM person 
LEFT JOIN appointment ON person.person_id = appointment.person_id
GROUP BY person.person_id;

Get selected value of a dropdown's item using jQuery

$("#dropDownId").val('2');
var SelectedValue= $("#dropDownId option:selected").text();
$(".ParentClass .select-value").html(SelectedValue);


<p class="inline-large-label button-height ParentClass" >
     <label for="large-label-2" class="label">Country <span style="color: Red;">*</span><small></small></label>
     <asp:DropDownList runat="server" ID="dropDownId " CssClass="select" Width="200px">          
    </asp:DropDownList>
</p>

jquery function setInterval

Don't pass the result of swapImages to setInterval by invoking it. Just pass the function, like this:

setInterval(swapImages, 1000);

No Exception while type casting with a null in java

This language feature is convenient in this situation.

public String getName() {
  return (String) memberHashMap.get("Name");
}

If memberHashMap.get("Name") returns null, you'd still want the method above to return null without throwing an exception. No matter what the class is, null is null.

Is there a color code for transparent in HTML?

You can specify value to background-color using rgba(), as:

.style{
        background-color: rgba(100, 100, 100, 0.5);
}

0.5 is the transparency value

0.5 is more like semi-transparent, changing the value from 0.5 to 0 gave me true transparency.

"npm config set registry https://registry.npmjs.org/" is not working in windows bat file

Probably I am too late to answer. But if anybody need it, following works fine, as I have used it a lot of times.

npm config set registry=https://registry.npmjs.com/

How to restart adb from root to user mode?

For quick steps just check summary. If interested to know details, go on to read below.

adb is a daemon. Doing ps adb we can see its process.

shell@grouper:/ $ ps adb
USER     PID   PPID  VSIZE  RSS     WCHAN    PC        NAME
shell     133   1     4636   212   ffffffff 00000000 S /sbin/adbd

I just checked what additional property variables it is using when adb is running as root and user.

adb user mode :

shell@grouper:/ $ getprop | grep adb                                         
[init.svc.adbd]: [running]
[persist.sys.usb.config]: [mtp,adb]
[ro.adb.secure]: [1]
[sys.usb.config]: [mtp,adb]
[sys.usb.state]: [mtp,adb]

adb root mode :

shell@grouper:/ # getprop | grep adb                                         
[init.svc.adbd]: [running]
[persist.sys.usb.config]: [mtp,adb]
[ro.adb.secure]: [1]
[service.adb.root]: [1]
[sys.usb.config]: [mtp,adb]
[sys.usb.state]: [mtp,adb]

We can see that service.adb.root is a new prop variable that came up when we did adb root.

So, to change back adb to user from root, I went ahead and made this 0

setprop service.adb.root 0

But this did not change anything.

Then I went ahead and killed the process (with an intention to restart the process). The pid of adbd process in my device is 133

kill -9 133

I exited from shell automatically after I had killed the process.

I did adb shell again it was in user mode.

SUMMARY :

So, we have 3 very simple steps.

  1. Enter adb shell as a root.
  2. setprop service.adb.root 0
  3. kill -9 (pid of adbd)

After these steps just re-enter the shell with adb shell and you are back on your device as a user.

SQL order string as number

Another and simple way

ORDER BY ABS(column_name)

SQL Error: ORA-00936: missing expression

  1  

     select ename as name,
      2  sal as salary,
      3  dept,deptno,
      4   from (TABLE_NAME or SUBQUERY)
      5   emp, emp2,  dept
      6    where
      7   emp.deptno = dept.deptno and
      8   emp2.deptno = emp.deptno
      9*  order by dept.dname

 from (TABLE_NAME or SUBQUERY)
 *
ERROR at line 4:
ORA-00936: missing expression`  select ename as name,
 sal as salary,
 dept,deptno,
  from (TABLE_NAME or SUBQUERY)
  emp, emp2,  dept
   where
  emp.deptno = dept.deptno and
  emp2.deptno = emp.deptno
  order by dept.dname`

The remote end hung up unexpectedly while git cloning

This is due the internet connectivity issue, i faced the same issue. I did a shallow copy of code using

git clone --depth 1 //FORKLOCATION

Later unshallowed the clone using

git fetch --unshallow

How to copy and edit files in Android shell?

You can do it without root permissions:

cat srcfile > /mnt/sdcard/dstfile

How can I list (ls) the 5 last modified files in a directory?

ls -t list files by creation time not last modified time. Use ls -ltc if you want to list files by last modified time from last to first(top to bottom). Thus to list the last n: ls -ltc | head ${n}

Background images: how to fill whole div if image is small and vice versa

Resize the image to fit the div size.
With CSS3 you can do this:

/* with CSS 3 */
#yourdiv {  
    background: url('bgimage.jpg') no-repeat;
    background-size: 100%;
}

How Do you Stretch a Background Image in a Web Page:

About opacity

#yourdiv {
    opacity: 0.4;
    filter: alpha(opacity=40); /* For IE8 and earlier */
}

Or look at CSS Image Opacity / Transparency

C++ convert hex string to signed integer

Working example with strtoul will be:

#include <cstdlib>
#include <iostream>
using namespace std;

int main() { 
    string s = "fffefffe";
    char * p;
    long n = strtoul( s.c_str(), & p, 16 ); 
    if ( * p != 0 ) {  
        cout << "not a number" << endl;
    }    else {  
        cout << n << endl;
    }
}

strtol converts string to long. On my computer numeric_limits<long>::max() gives 0x7fffffff. Obviously that 0xfffefffe is greater than 0x7fffffff. So strtol returns MAX_LONG instead of wanted value. strtoul converts string to unsigned long that's why no overflow in this case.

Ok, strtol is considering input string not as 32-bit signed integer before convertation. Funny sample with strtol:

#include <cstdlib>
#include <iostream>
using namespace std;

int main() { 
    string s = "-0x10002";
    char * p;
    long n = strtol( s.c_str(), & p, 16 ); 
    if ( * p != 0 ) {  
        cout << "not a number" << endl;
    }    else {  
        cout << n << endl;
    }
}

The code above prints -65538 in console.

\r\n, \r and \n what is the difference between them?

A carriage return (\r) makes the cursor jump to the first column (begin of the line) while the newline (\n) jumps to the next line and eventually to the beginning of that line. So to be sure to be at the first position within the next line one uses both.

How to deal with page breaks when printing a large HTML table

I've tried all suggestions given above and found simple and working cross browser solution for this issue. There is no styles or page break needed for this solution. For the solution, the format of the table should be like:

<table>
    <thead>  <!-- there should be <thead> tag-->
        <td>Heading</td> <!--//inside <thead> should be <td> it should not be <th>-->
    </thead>
    <tbody><!---<tbody>also must-->
        <tr>
            <td>data</td>
        </tr>
        <!--100 more rows-->
    </tbody>
</table>

Above format tested and working in cross browsers

What is the difference between re.search and re.match?

You can refer the below example to understand the working of re.match and re.search

a = "123abc"
t = re.match("[a-z]+",a)
t = re.search("[a-z]+",a)

re.match will return none, but re.search will return abc.

Is there a function to round a float in C or do I need to write my own?

#include <math.h>

double round(double x);
float roundf(float x);

Don't forget to link with -lm. See also ceil(), floor() and trunc().

Appending the same string to a list of strings in Python

Updating with more options

list1 = ['foo', 'fob', 'faz', 'funk']
addstring = 'bar'
for index, value in enumerate(list1):
    list1[index] = addstring + value #this will prepend the string
    #list1[index] = value + addstring this will append the string

Avoid using keywords as variables like 'list', renamed 'list' as 'list1' instead

Inserting values into tables Oracle SQL

INSERT
INTO    Employee 
        (emp_id, emp_name, emp_address, emp_state, emp_position, emp_manager)
SELECT  '001', 'John Doe', '1 River Walk, Green Street', state_id, position_id, manager_id
FROM    dual
JOIN    state s
ON      s.state_name = 'New York'
JOIN    positions p
ON      p.position_name = 'Sales Executive'
JOIN    manager m
ON      m.manager_name = 'Barry Green'

Note that but a single spelling mistake (or an extra space) will result in a non-match and nothing will be inserted.

Appending an element to the end of a list in Scala

That's because you shouldn't do it (at least with an immutable list). If you really really need to append an element to the end of a data structure and this data structure really really needs to be a list and this list really really has to be immutable then do eiher this:

(4 :: List(1,2,3).reverse).reverse

or that:

List(1,2,3) ::: List(4)

What is the difference between an int and a long in C++?

It depends on your compiler. You are guaranteed that a long will be at least as large as an int, but you are not guaranteed that it will be any longer.

Setting session variable using javascript

You can use

sessionStorage.SessionName = "SessionData" ,

sessionStorage.getItem("SessionName") and

sessionStorage.setItem("SessionName","SessionData");

See the supported browsers on http://caniuse.com/namevalue-storage

Adding click event for a button created dynamically using jQuery

Use a delegated event handler bound to the container:

$('#pg_menu_content').on('click', '#btn_a', function(){
    console.log(this.value);
});

That is, bind to an element that exists at the moment that the JS runs (I'm assuming #pg_menu_content exists when the page loads), and supply a selector in the second parameter to .on(). When a click occurs on #pg_menu_content element jQuery checks whether it applied to a child of that element which matches the #btn_a selector.

Either that or bind a standard (non-delegated) click handler after creating the button.

Either way, within the click handler this will refer to the button in question, so this.value will give you its value.

Trigger a Travis-CI rebuild without pushing a commit?

I know you said without pushing a commit, but something that is handy, if you are working on a branch other than master, is to commit an empty commit.

git commit --allow-empty -m "Trigger"

You can rebase in the end and remove squash/remove the empty commits and works across all git hooks :)

Making a mocked method return an argument that was passed to it

You might want to use verify() in combination with the ArgumentCaptor to assure execution in the test and the ArgumentCaptor to evaluate the arguments:

ArgumentCaptor<String> argument = ArgumentCaptor.forClass(String.class);
verify(mock).myFunction(argument.capture());
assertEquals("the expected value here", argument.getValue());

The argument's value is obviously accessible via the argument.getValue() for further manipulation / checking /whatever.

Program to find prime numbers

People have mentioned a couple of the building blocks toward doing this efficiently, but nobody's really put the pieces together. The sieve of Eratosthenes is a good start, but with it you'll run out of memory long before you reach the limit you've set. That doesn't mean it's useless though -- when you're doing your loop, what you really care about are prime divisors. As such, you can start by using the sieve to create a base of prime divisors, then use those in the loop to test numbers for primacy.

When you write the loop, however, you really do NOT want to us sqrt(i) in the loop condition as a couple of answers have suggested. You and I know that the sqrt is a "pure" function that always gives the same answer if given the same input parameter. Unfortunately, the compiler does NOT know that, so if use something like '<=Math.sqrt(x)' in the loop condition, it'll re-compute the sqrt of the number every iteration of the loop.

You can avoid that a couple of different ways. You can either pre-compute the sqrt before the loop, and use the pre-computed value in the loop condition, or you can work in the other direction, and change i<Math.sqrt(x) to i*i<x. Personally, I'd pre-compute the square root though -- I think it's clearer and probably a bit faster--but that depends on the number of iterations of the loop (the i*i means it's still doing a multiplication in the loop). With only a few iterations, i*i will typically be faster. With enough iterations, the loss from i*i every iteration outweighs the time for executing sqrt once outside the loop.

That's probably adequate for the size of numbers you're dealing with -- a 15 digit limit means the square root is 7 or 8 digits, which fits in a pretty reasonable amount of memory. On the other hand, if you want to deal with numbers in this range a lot, you might want to look at some of the more sophisticated prime-checking algorithms, such as Pollard's or Brent's algorithms. These are more complex (to put it mildly) but a lot faster for large numbers.

There are other algorithms for even bigger numbers (quadratic sieve, general number field sieve) but we won't get into them for the moment -- they're a lot more complex, and really only useful for dealing with really big numbers (the GNFS starts to be useful in the 100+ digit range).

Attempted to read or write protected memory. This is often an indication that other memory is corrupt

The problem may be due to mixed build platforms DLLs in the project. i.e You build your project to Any CPU but have some DLLs in the project already built for x86 platform. These will cause random crashes because of different memory mapping of 32bit and 64bit architecture. If all the DLLs are built for one platform the problem can be solved.

Is there functionality to generate a random character in Java?

You could also use the RandomStringUtils from the Apache Commons project:

Dependency:

<dependency> 
  <groupId>org.apache.commons</groupId> 
  <artifactId>commons-lang3</artifactId> 
  <version>3.8.1</version> 
</dependency>

Usages:

RandomStringUtils.randomAlphabetic(stringLength);
RandomStringUtils.randomAlphanumeric(stringLength);

How to access to a child method from the parent in vue.js

Parent-Child communication in VueJS

Given a root Vue instance is accessible by all descendants via this.$root, a parent component can access child components via the this.$children array, and a child component can access it's parent via this.$parent, your first instinct might be to access these components directly.

The VueJS documentation warns against this specifically for two very good reasons:

  • It tightly couples the parent to the child (and vice versa)
  • You can't rely on the parent's state, given that it can be modified by a child component.

The solution is to use Vue's custom event interface

The event interface implemented by Vue allows you to communicate up and down the component tree. Leveraging the custom event interface gives you access to four methods:

  1. $on() - allows you to declare a listener on your Vue instance with which to listen to events
  2. $emit() - allows you to trigger events on the same instance (self)

Example using $on() and $emit():

_x000D_
_x000D_
const events = new Vue({}),_x000D_
    parentComponent = new Vue({_x000D_
      el: '#parent',_x000D_
      ready() {_x000D_
        events.$on('eventGreet', () => {_x000D_
          this.parentMsg = `I heard the greeting event from Child component ${++this.counter} times..`;_x000D_
        });_x000D_
      },_x000D_
      data: {_x000D_
        parentMsg: 'I am listening for an event..',_x000D_
        counter: 0_x000D_
      }_x000D_
    }),_x000D_
    childComponent = new Vue({_x000D_
      el: '#child',_x000D_
      methods: {_x000D_
      greet: function () {_x000D_
        events.$emit('eventGreet');_x000D_
        this.childMsg = `I am firing greeting event ${++this.counter} times..`;_x000D_
      }_x000D_
    },_x000D_
    data: {_x000D_
      childMsg: 'I am getting ready to fire an event.',_x000D_
      counter: 0_x000D_
    }_x000D_
  });
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/vue/1.0.28/vue.min.js"></script>_x000D_
_x000D_
<div id="parent">_x000D_
  <h2>Parent Component</h2>_x000D_
  <p>{{parentMsg}}</p>_x000D_
</div>_x000D_
_x000D_
<div id="child">_x000D_
  <h2>Child Component</h2>_x000D_
  <p>{{childMsg}}</p>_x000D_
  <button v-on:click="greet">Greet</button>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Answer taken from the original post: Communicating between components in VueJS

img tag displays wrong orientation

If you have access to Linux, then open a terminal, cd to the directory containing your images and then run

mogrify -auto-orient *

This should permanently fix the orientation issues on all the images.

Converting Java objects to JSON with Jackson

public class JSONConvector {

    public static String toJSON(Object object) throws JSONException, IllegalAccessException {
        String str = "";
        Class c = object.getClass();
        JSONObject jsonObject = new JSONObject();
        for (Field field : c.getDeclaredFields()) {
            field.setAccessible(true);
            String name = field.getName();
            String value = String.valueOf(field.get(object));
            jsonObject.put(name, value);
        }
        System.out.println(jsonObject.toString());
        return jsonObject.toString();
    }


    public static String toJSON(List list ) throws JSONException, IllegalAccessException {
        JSONArray jsonArray = new JSONArray();
        for (Object i : list) {
            String jstr = toJSON(i);
            JSONObject jsonObject = new JSONObject(jstr);
            jsonArray.put(jsonArray);
        }
        return jsonArray.toString();
    }
}

intelliJ IDEA 13 error: please select Android SDK

You have to Select Build Tool Version from your project setting.

  1. Select Project App Folder
  2. Press F4 OR Right Click on Project App Folder and open Module Settings In The Properties tab select Build Tool Version from List

This will work on my side i hope it will help you.

Java GC (Allocation Failure)

"Allocation Failure" is cause of GC to kick is not correct. It is an outcome of GC operation.

GC kicks in when there is no space to allocate( depending on region minor or major GC is performed). Once GC is performed if space is freed good enough, but if there is not enough size it fails. Allocation Failure is one such failure. Below document have good explanation https://docs.oracle.com/javase/8/docs/technotes/guides/vm/gctuning/g1_gc.html

Unable to set default python version to python3 in ubuntu

To change to python3, you can use the following command in terminal alias python=python3.

How to hide element using Twitter Bootstrap and show it using jQuery?

Bootstrap, JQuery, namespaces... What is wrong with a simple:

var x = document.getElementById('my-div');
x.className.replace(/\bhide\b/, ''); //remove any hide class
x.style.display = ''; //show
x.style.display = 'none'; //hide

You can create a little helper function, KISS compliant:

function mydisplay(id, display) {
    var node = (typeof id == 'string') ? document.getElementById(id) : id;
    node.className.replace(/\bhide\b/, '');
    if (node) {
        if (typeof display == 'undefined') {
            display = (node.style.display != 'none');
        } else if (typeof display == 'string' && display == 'toggle') {
            display = mydisplay(node, !mydisplay(node));
        } else {
            node.style.display = (display) ? '' : 'none';
        }
    }
    return display;
}
is_hidden = mydisplay('my-div'); //actual state
mydisplay('my-div', false); //hide
mydisplay('my-div', true); //show
mydisplay('my-div', 'toggle'); //toggle state

Setting up and using Meld as your git difftool and mergetool

I prefer to setup meld as a separate command, like so:

git config --global alias.meld '!git difftool -t meld --dir-diff'

This makes it similar to the git-meld.pl script here: https://github.com/wmanley/git-meld

You can then just run

git meld

Appending to an object

You should really go with the array of alerts suggestions, but otherwise adding to the object you mentioned would look like this:

alerts[3]={"app":"goodbyeworld","message":"cya"};

But since you shouldn't use literal numbers as names quote everything and go with

alerts['3']={"app":"goodbyeworld","message":"cya"};

or you can make it an array of objects.

Accessing it looks like

alerts['1'].app
=> "helloworld"

MySQL connection not working: 2002 No such file or directory

If you use Linux: the path to the mysql.sock file is wrong. This is usually because you are using (LAMPP) XAMPP and it isn't in /tmp/mysql.sock

Open the php.ini file and find this line:

mysql.default_socket

And make it

mysql.default_socket = /path/to/mysql.sock

Get an object's class name at runtime

See this question.

Since TypeScript is compiled to JavaScript, at runtime you are running JavaScript, so the same rules will apply.

onclick event function in JavaScript

Two observations:

  1. You should write

    <input type="button" value="button text" />
    

    instead of

    <input type="button">button text</input>
    
  2. You should rename your function. The function click() is already defined on a button (it simulates a click), and gets a higher priority then your method.

Note that there are a couple of suggestions here that are plain wrong, and you shouldn't spend to much time on them:

  • Do not use onclick="javascript:myfunc()". Only use the javascript: prefix inside the href attribute of a hyperlink: <a href="javascript:myfunc()">.
  • You don't have to end with a semicolon. onclick="foo()" and onclick="foo();" both work just fine.
  • Event attributes in HTML are not case sensitive, so onclick, onClick and ONCLICK all work. It is common practice to write attributes in lowercase: onclick. note that javascript itself is case sensitive, so if you write document.getElementById("...").onclick = ..., then it must be all lowercase.

Rails create or update magic?

Add this to your model:

def self.update_or_create_by(args, attributes)
  obj = self.find_or_create_by(args)
  obj.update(attributes)
  return obj
end

With that, you can:

User.update_or_create_by({name: 'Joe'}, attributes)

Passing string parameter in JavaScript function

Use this:

document.write('<td width="74"><button id="button" type="button" onclick="myfunction('" + name + "')">click</button></td>')

Best Way to read rss feed in .net Using C#

Add System.ServiceModel in references

Using SyndicationFeed:

string url = "http://fooblog.com/feed";
XmlReader reader = XmlReader.Create(url);
SyndicationFeed feed = SyndicationFeed.Load(reader);
reader.Close();
foreach (SyndicationItem item in feed.Items)
{
    String subject = item.Title.Text;    
    String summary = item.Summary.Text;
    ...                
}

Laravel 5.2 - Use a String as a Custom Primary Key for Eloquent Table becomes 0

Theres two properties on the model you need to set. The first $primaryKey to tell the model what column to expect the primary key on. The second $incrementing so it knows the primary key isn't a linear auto incrementing value.

class MyModel extends Model
{
    protected $primaryKey = 'my_column';

    public $incrementing = false;
}

For more info see the Primary Keys section in the documentation on Eloquent.

Get class name of object as string in Swift

Swift 3.0: You can create an extension like this one.. It gives back the class name without the project name

extension NSObject {
    var className: String {
        return NSStringFromClass(self as! AnyClass).components(separatedBy: ".").last ?? ""
    }

    public class var className: String {
        return NSStringFromClass(self).components(separatedBy: ".").last ?? ""
    }
}

Calendar.getInstance(TimeZone.getTimeZone("UTC")) is not returning UTC time

Try to use GMT instead of UTC. They refer to the same time zone, yet the name GMT is more common and might work.

How to convert JSON to string?

Try to Use JSON.stringify

Regards

Get Hours and Minutes (HH:MM) from date

You can easily use Format() function instead of all the casting for sql 2012 and above only

SELECT FORMAT(GETDATE(),'hh:mm')

This is by far the best way to do the required conversion.

PHP code to get selected text of a combo box

you can make a jQuery onChange event to get the text from the combobox when the user select one of them:

<script>    
     $( "select" )
     .change(function () {
     var str = "";
     $( "select option:selected" ).each(function() {
     str += $( this ).text() + " ";
     });
     $('#EvaluationName').val(str);
     })
     .change();
 </script>

When you select an option, it will save the text in an Input hidde

  <input type="hidden" id="EvaluationName" name="EvaluationName" value="<?= $Evaluation ?>" />

After that, when you submit the form, just catch up the value of the input

$Evaluation = $_REQUEST['EvaluationName'];

Then you can do wathever you want with the text, for instance save it in a session variable and send it to other page. etc.

Force uninstall of Visual Studio

So Soumyaansh's Revo Uninstaller Pro fix worked for me :) ( After 2 days of troubleshooting other options {screams internally 😀} ).

I did run into the an issue with his method though, "Could not find a suitable SDK to target" even though I selected to install Visual Studio with custom settings and selected the SDK I wanted to install. You may need to download the Windows 10 Standalone SDK to resolved this, in order to develop UWP apps if you see this same error after reinstalling Visual Studio.

To do this

  1. Uninstall any Windows 10 SDKs that me on the system (the naming schem for them looks like Windows 10 SDK (WINDOWS_VERSION_NUMBER_HERE) -> Windows 10 SDK (14393) etc . . .). If there are no SDKs on your system go to step 2!
  2. All that's left is to download the SDKs you want by Checking out the SDK Archive for all available SDKs and you should be good to go in developing for the UWP!

R Plotting confidence bands with ggplot

require(ggplot2)
require(nlme)

set.seed(101)
mp <-data.frame(year=1990:2010)
N <- nrow(mp)

mp <- within(mp,
         {
             wav <- rnorm(N)*cos(2*pi*year)+rnorm(N)*sin(2*pi*year)+5
             wow <- rnorm(N)*wav+rnorm(N)*wav^3
         })

m01 <- gls(wow~poly(wav,3), data=mp, correlation = corARMA(p=1))

Get fitted values (the same as m01$fitted)

fit <- predict(m01)

Normally we could use something like predict(...,se.fit=TRUE) to get the confidence intervals on the prediction, but gls doesn't provide this capability. We use a recipe similar to the one shown at http://glmm.wikidot.com/faq :

V <- vcov(m01)
X <- model.matrix(~poly(wav,3),data=mp)
se.fit <- sqrt(diag(X %*% V %*% t(X)))

Put together a "prediction frame":

predframe <- with(mp,data.frame(year,wav,
                                wow=fit,lwr=fit-1.96*se.fit,upr=fit+1.96*se.fit))

Now plot with geom_ribbon

(p1 <- ggplot(mp, aes(year, wow))+
    geom_point()+
    geom_line(data=predframe)+
    geom_ribbon(data=predframe,aes(ymin=lwr,ymax=upr),alpha=0.3))

year vs wow

It's easier to see that we got the right answer if we plot against wav rather than year:

(p2 <- ggplot(mp, aes(wav, wow))+
    geom_point()+
    geom_line(data=predframe)+
    geom_ribbon(data=predframe,aes(ymin=lwr,ymax=upr),alpha=0.3))

wav vs wow

It would be nice to do the predictions with more resolution, but it's a little tricky to do this with the results of poly() fits -- see ?makepredictcall.

MySQL Insert query doesn't work with WHERE clause

You can do conditional INSERT based on user input. This query will do insert only if input vars '$userWeight' and '$userDesiredWeight' are not blank

INSERT INTO Users(weight, desiredWeight )
select '$userWeight', '$userDesiredWeight'  
FROM (select 1 a ) dummy
WHERE '$userWeight' != '' AND '$userDesiredWeight'!='';

CSS @font-face not working in ie

You could use the Google Font API. They say it works from IE 6 and up. (I've not tested this.)

Google’s serving infrastructure takes care of converting the font into a format compatible with any modern browser (including Internet Explorer 6 and up), ...

getDate with Jquery Datepicker

This line looks questionable:

page_output.innerHTML = str_output;

You can use .innerHTML within jQuery, or you can use it without, but you have to address the selector semantically one way or the other:

$('#page_output').innerHTML /* for jQuery */
document.getElementByID('page_output').innerHTML /* for standard JS */

or better yet

$('#page_output').html(str_output);

Web Application Problems (web.config errors) HTTP 500.19 with IIS7.5 and ASP.NET v2

Windows 7

Try this,

run cmd as Admin.

Unistall all iis.

start /w pkgmgr.exe /uu:IIS-WebServerRole;WAS-WindowsActivationService

Reinstall iis and normaly it's work

Alain

How to convert std::string to LPCSTR?

The MultiByteToWideChar answer that Charles Bailey gave is the correct one. Because LPCWSTR is just a typedef for const WCHAR*, widestr in the example code there can be used wherever a LPWSTR is expected or where a LPCWSTR is expected.

One minor tweak would be to use std::vector<WCHAR> instead of a manually managed array:

// using vector, buffer is deallocated when function ends
std::vector<WCHAR> widestr(bufferlen + 1);

::MultiByteToWideChar(CP_ACP, 0, instr.c_str(), instr.size(), &widestr[0], bufferlen);

// Ensure wide string is null terminated
widestr[bufferlen] = 0;

// no need to delete; handled by vector

Also, if you need to work with wide strings to start with, you can use std::wstring instead of std::string. If you want to work with the Windows TCHAR type, you can use std::basic_string<TCHAR>. Converting from std::wstring to LPCWSTR or from std::basic_string<TCHAR> to LPCTSTR is just a matter of calling c_str. It's when you're changing between ANSI and UTF-16 characters that MultiByteToWideChar (and its inverse WideCharToMultiByte) comes into the picture.

Check if string contains only letters in javascript

The fastest way is to check if there is a non letter:

if (!/[^a-zA-Z]/.test(word))

iOS: Multi-line UILabel in Auto Layout

None of the different solutions found in the many topics on the subject worked perfectly for my case (x dynamic multiline labels in dynamic table view cells) .

I found a way to do it :

After having set the constraints on your label and set its multiline property to 0, make a subclass of UILabel ; I called mine AutoLayoutLabel :

@implementation AutoLayoutLabel

- (void)layoutSubviews{
    [self setNeedsUpdateConstraints];
    [super layoutSubviews];
    self.preferredMaxLayoutWidth = CGRectGetWidth(self.bounds);
}

@end

HTTP status code 0 - Error Domain=NSURLErrorDomain?

We got the error:

GET http://localhost/pathToWebSite/somePage.aspx raised an http.status: 0 error

That call is made from windows task that calls a VBS file, so to troubleshoot the problem, pointed a browser to the url and we get a Privacy Error:

Your connection is not private

Attackers might be trying to steal your information from localhost (for example, passwords, messages, or credit cards). NET::ERR_CERT_COMMON_NAME_INVALID

Automatically report details of possible security incidents to Google. Privacy policy Back to safety This server could not prove that it is localhost; its security certificate is from *.ourdomain.com. This may be caused by a misconfiguration or an attacker intercepting your connection. Learn more.

This is because we have a IIS URL Rewrite rule set to force connections use https. That rule diverts http://localhost to https://localhost but our SSL certificate is based on an outside facing domain name not localhost, thus the error which is reported as status code 0. So a Privacy error could be a very obscure reason for this status code 0.

In our case the solution was to add an exception to the rule for localhost and allow http://localhost/pathToWebSite/somePage.aspx to use http. Obscure, yes, but I'll run into this next year and now I'll find my answer in a google search.

Excel VBA - Sum up a column

I have a label on my form receiving the sum of numbers from Column D in Sheet1. I am only interested in rows 2 to 50, you can use a row counter if your row count is dynamic. I have some blank entries as well in column D and they are ignored.

Me.lblRangeTotal = Application.WorksheetFunction.Sum(ThisWorkbook.Sheets("Sheet1").Range("D2:D50"))

Get request URL in JSP which is forwarded by Servlet

None of these attributes are reliable because per the servlet spec (2.4, 2.5 and 3.0), these attributes are overridden if you include/forward a second time (or if someone calls getNamedDispatcher). I think the only reliable way to get the original request URI/query string is to stick a filter at the beginning of your filter chain in web.xml that sets your own custom request attributes based on request.getRequestURI()/getQueryString() before any forwards/includes take place.

http://www.caucho.com/resin-3.0/webapp/faq.xtp contains an excellent summary of how this works (minus the technical note that a second forward/include messes up your ability to use these attributes).

How to calculate the running time of my program?

Beside the well-known (and already mentioned) System.currentTimeMillis() and System.nanoTime() there is also a neat library called perf4j which might be useful too, depending on your purpose of course.

AngularJS accessing DOM elements inside directive template

This answer comes a little bit late, but I just was in a similar need.

Observing the comments written by @ganaraj in the question, One use case I was in the need of is, passing a classname via a directive attribute to be added to a ng-repeat li tag in the template.

For example, use the directive like this:

<my-directive class2add="special-class" />

And get the following html:

<div>
    <ul>
       <li class="special-class">Item 1</li>
       <li class="special-class">Item 2</li>
    </ul>
</div>

The solution found here applied with templateUrl, would be:

app.directive("myDirective", function() {
    return {
        template: function(element, attrs){
            return '<div><ul><li ng-repeat="item in items" class="'+attrs.class2add+'"></ul></div>';
        },
        link: function(scope, element, attrs) {
            var list = element.find("ul");
        }
    }
});

Just tried it successfully with AngularJS 1.4.9.

Hope it helps.

Find MongoDB records where array field is not empty

Use the $elemMatch operator: according to the documentation

The $elemMatch operator matches documents that contain an array field with at least one element that matches all the specified query criteria.

$elemMatches makes sure that the value is an array and that it is not empty. So the query would be something like

ME.find({ pictures: { $elemMatch: {$exists: true }}})

PS A variant of this code is found in MongoDB University's M121 course.

How do I "shake" an Android device within the Android emulator to bring up the dev menu to debug my React Native app

I am on Mac OS so when I press Command, it enable zooming option. Here is my solution

  • Open Configuration window [...] button
  • Go toSettings tab ->General tab -> Send keyboard shortcuts to field
  • Change value to Virtual device" as shown in the picture

After that focus on the emulator and press Command + M, the dev menu appears.

Emulator Option -> Settings -> General

Using JavaMail with TLS

Good post, the line

props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");

is mandatory if the SMTP server uses SSL Authentication, like the GMail SMTP server does. However if the server uses Plaintext Authentication over TLS, it should not be present, because Java Mail will complain about the initial connection being plaintext.

Also make sure you are using the latest version of Java Mail. Recently I used some old Java Mail jars from a previous project and could not make the code work, because the login process was failing. After I have upgraded to the latest version of Java Mail, the reason of the error became clear: it was a javax.net.ssl.SSLHandshakeException, which was not thrown up in the old version of the lib.

How to fix org.hibernate.LazyInitializationException - could not initialize proxy - no Session

I encountered the same issue. I think another way to fix this is that you can change the query to join fetch your Element from Model as follows:

Query query = session.createQuery("from Model m join fetch m.element where modelGroup.id = :modelGroupId")

Coarse-grained vs fine-grained

coarse grained and fine grained. Both of these modes define how the cores are shared between multiple Spark tasks. As the name suggests, fine-grained mode is responsible for sharing the cores at a more granular level. Fine-grained mode has been deprecated by Spark and will soon be removed.

How to copy file from one location to another location?

  public static void copyFile(File oldLocation, File newLocation) throws IOException {
        if ( oldLocation.exists( )) {
            BufferedInputStream  reader = new BufferedInputStream( new FileInputStream(oldLocation) );
            BufferedOutputStream  writer = new BufferedOutputStream( new FileOutputStream(newLocation, false));
            try {
                byte[]  buff = new byte[8192];
                int numChars;
                while ( (numChars = reader.read(  buff, 0, buff.length ) ) != -1) {
                    writer.write( buff, 0, numChars );
                }
            } catch( IOException ex ) {
                throw new IOException("IOException when transferring " + oldLocation.getPath() + " to " + newLocation.getPath());
            } finally {
                try {
                    if ( reader != null ){                      
                        writer.close();
                        reader.close();
                    }
                } catch( IOException ex ){
                    Log.e(TAG, "Error closing files when transferring " + oldLocation.getPath() + " to " + newLocation.getPath() ); 
                }
            }
        } else {
            throw new IOException("Old location does not exist when transferring " + oldLocation.getPath() + " to " + newLocation.getPath() );
        }
    }  

Python: printing a file to stdout

You can try this.

txt = <file_path>
txt_opn = open(txt)
print txt_opn.read()

This will give you file output.

How to animate the change of image in an UIImageView?

[UIView transitionWithView:textFieldimageView
                  duration:0.2f
                   options:UIViewAnimationOptionTransitionCrossDissolve
                animations:^{
                    imageView.image = newImage;
                } completion:nil];

is another possibility

How to drop unique in MySQL?

Try it to remove uique of a column:

ALTER TABLE  `0_ms_labdip_details` DROP INDEX column_tcx

Run this code in phpmyadmin and remove unique of column

ASP.NET MVC3 - textarea with @Html.EditorFor

Declare in your Model with

  [DataType(DataType.MultilineText)]
  public string urString { get; set; }

Then in .cshtml can make use of editor as below. you can make use of @cols and @rows for TextArea size

     @Html.EditorFor(model => model.urString, new { htmlAttributes = new { @class = "",@cols = 35, @rows = 3 } })

Thanks !

How do I read a resource file from a Java jar file?

Outside of your technique, why not use the standard Java JarFile class to get the references you want? From there most of your problems should go away.

Regular expression to find two strings anywhere in input

/^.*?\bcat\b.*?\bmat\b.*?$/m

Using the m modifier (which ensures the beginning/end metacharacters match on line breaks rather than at the very beginning and end of the string):

  • ^ matches the line beginning
  • .*? matches anything on the line before...
  • \b matches a word boundary the first occurrence of a word boundary (as @codaddict discussed)
  • then the string cat and another word boundary; note that underscores are treated as "word" characters, so _cat_ would not match*;
  • .*?: any characters before...
  • boundary, mat, boundary
  • .*?: any remaining characters before...
  • $: the end of the line.

It's important to use \b to ensure the specified words aren't part of longer words, and it's important to use non-greedy wildcards (.*?) versus greedy (.*) because the latter would fail on strings like "There is a cat on top of the mat which is under the cat." (It would match the last occurrence of "cat" rather than the first.)

* If you want to be able to match _cat_, you can use:

/^.*?(?:\b|_)cat(?:\b|_).*?(?:\b|_)mat(?:\b|_).*?$/m

which matches either underscores or word boundaries around the specified words. (?:) indicates a non-capturing group, which can help with performance or avoid conflicted captures.

Edit: A question was raised in the comments about whether the solution would work for phrases rather than just words. The answer is, absolutely yes. The following would match "A line which includes both the first phrase and the second phrase":

/^.*?(?:\b|_)first phrase here(?:\b|_).*?(?:\b|_)second phrase here(?:\b|_).*?$/m

Edit 2: If order doesn't matter you can use:

/^.*?(?:\b|_)(first(?:\b|_).*?(?:\b|_)second|second(?:\b|_).*?(?:\b|_)first)(?:\b|_).*?$/m

And if performance is really an issue here, it's possible lookaround (if your regex engine supports it) might (but probably won't) perform better than the above, but I'll leave both the arguably more complex lookaround version and performance testing as an exercise to the questioner/reader.

Edited per @Alan Moore's comment. I didn't have a chance to test it, but I'll take your word for it.

How to send a JSON object over Request with Android?

public class getUserProfile extends AsyncTask<Void, String, JSONArray> {
    JSONArray array;
    @Override
    protected JSONArray doInBackground(Void... params) {

        try {
            commonurl cu = new commonurl();
            String u = cu.geturl("tempshowusermain.php");
            URL url =new URL(u);
          //  URL url = new URL("http://192.168.225.35/jabber/tempshowusermain.php");
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setRequestProperty("Content-Type", "application/json");
            httpURLConnection.setRequestProperty("Accept", "application/json");
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setRequestProperty("Connection", "Keep-Alive");
            httpURLConnection.setDoInput(true);
            httpURLConnection.connect();

            JSONObject jsonObject=new JSONObject();
            jsonObject.put("lid",lid);


            DataOutputStream outputStream = new DataOutputStream(httpURLConnection.getOutputStream());
            outputStream.write(jsonObject.toString().getBytes("UTF-8"));

            int code = httpURLConnection.getResponseCode();
            if (code == 200) {
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(httpURLConnection.getInputStream()));

                StringBuffer stringBuffer = new StringBuffer();
                String line;

                while ((line = bufferedReader.readLine()) != null) {
                    stringBuffer.append(line);
                }
                object =  new JSONObject(stringBuffer.toString());
             //   array = new JSONArray(stringBuffer.toString());
                array = object.getJSONArray("response");

            }

        } catch (Exception e) {

            e.printStackTrace();
        }
        return array;


    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();



    }

    @Override
    protected void onPostExecute(JSONArray array) {
        super.onPostExecute(array);
        try {
            for (int x = 0; x < array.length(); x++) {

                object = array.getJSONObject(x);
                ComonUserView commUserView=new ComonUserView();//  commonclass.setId(Integer.parseInt(jsonObject2.getString("pid").toString()));
                //pidArray.add(jsonObject2.getString("pid").toString());

                commUserView.setLid(object.get("lid").toString());
                commUserView.setUname(object.get("uname").toString());
                commUserView.setAboutme(object.get("aboutme").toString());
                commUserView.setHeight(object.get("height").toString());
                commUserView.setAge(object.get("age").toString());
                commUserView.setWeight(object.get("weight").toString());
                commUserView.setBodytype(object.get("bodytype").toString());
                commUserView.setRelationshipstatus(object.get("relationshipstatus").toString());
                commUserView.setImagepath(object.get("imagepath").toString());
                commUserView.setDistance(object.get("distance").toString());
                commUserView.setLookingfor(object.get("lookingfor").toString());
                commUserView.setStatus(object.get("status").toString());

                cm.add(commUserView);
            }
            custuserprof = new customadapterformainprofile(getActivity(),cm,Tab3.this);
          gridusername.setAdapter(custuserprof);
            //  listusername.setAdapter(custuserprof);
            } catch (Exception e) {

                e.printStackTrace();
        }
    }

Lodash - difference between .extend() / .assign() and .merge()

Here's how extend/assign works: For each property in source, copy its value as-is to destination. if property values themselves are objects, there is no recursive traversal of their properties. Entire object would be taken from source and set in to destination.

Here's how merge works: For each property in source, check if that property is object itself. If it is then go down recursively and try to map child object properties from source to destination. So essentially we merge object hierarchy from source to destination. While for extend/assign, it's simple one level copy of properties from source to destination.

Here's simple JSBin that would make this crystal clear: http://jsbin.com/uXaqIMa/2/edit?js,console

Here's more elaborate version that includes array in the example as well: http://jsbin.com/uXaqIMa/1/edit?js,console

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

I had this exact problem when trying to run the Doodlz app, from the book Android for Programmers, on Mac OS X with Eclipse Juno.

After downloading and unzipping the demos from the book, I forgot to change the permission of the files. They were read-only on my system so this was the first issue.

The second issue was solved by selecting a build target on Eclipse. This was fixed by going to: Project > Properties , and clicking the Android field on the left panel to be able to select one option as the Project Build Target, which in my case was:

  Target Name     Vendor         Platform    API Level
> Google APIs     Google Inc.    4.0.3       15

Then cleaning and rebuilding the project showed no errors.

Finally, to run the app right-click the package (at the Package Explorer tab) and then select: Run As > Android Application

css selector to match an element without attribute x

For a more cross-browser solution you could style all inputs the way you want the non-typed, text, and password then another style the overrides that style for radios, checkboxes, etc.

input { border:solid 1px red; }

input[type=radio], 
input[type=checkbox], 
input[type=submit], 
input[type=reset], 
input[type=file] 
      { border:none; }

- Or -

could whatever part of your code that is generating the non-typed inputs give them a class like .no-type or simply not output at all? Additionally this type of selection could be done with jQuery.

R Markdown - changing font size and font type in html output

I think fontsize: command in YAML only works for LaTeX / pdf. Apart, in standard latex classes (article, book, and report) only three font sizes are accepted (10pt, 11pt, and 12pt).

Regarding appearance (different font types and colors), you can specify a theme:. See Appearance and Style.

I guess, what you are looking for is your own css. Make a file called style.css, save it in the same folder as your .Rmd and include it in the YAML header:

---
output:
  html_document:
    css: style.css
---

In the css-file you define your font-type and size:

/* Whole document: */
body{
  font-family: Helvetica;
  font-size: 16pt;
}
/* Headers */
h1,h2,h3,h4,h5,h6{
  font-size: 24pt;
}

How to run php files on my computer

php have a easy way to run a light server:
first cd into php file directory, then

php -S 127.0.0.1:8000

then you can run php

How can I call a function using a function pointer?

I usually use typedef to do it, but it may be overkill, if you do not have to use the function pointer too often..

//assuming bool is available (where I come from it is an enum)

typedef bool (*pmyfun_t)();

pmyfun_t pMyFun;

pMyFun=A; //pMyFun=&A is actually same

pMyFun();

Conditionally formatting cells if their value equals any value of another column

Another simpler solution is to use this formula in the conditional formatting (apply to column A):

=COUNTIF(B:B,A1)

Regards!

Matching special characters and letters in regex

Add them to the allowed characters, but you'll need to escape some of them, such as -]/\

var pattern = /^[a-zA-Z0-9!@#$%^&*()_+\-=\[\]{};':"\\|,.<>\/?]*$/

That way you can remove any individual character you want to disallow.

Also, you want to include the start and end of string placemarkers ^ and $

Update:

As elclanrs understood (and the rest of us didn't, initially), the only special characters needing to be allowed in the pattern are &-._

/^[\w&.\-]+$/

[\w] is the same as [a-zA-Z0-9_]

Though the dash doesn't need escaping when it's at the start or end of the list, I prefer to do it in case other characters are added. Additionally, the + means you need at least one of the listed characters. If zero is ok (ie an empty value), then replace it with a * instead:

/^[\w&.\-]*$/

Do I cast the result of malloc?

This question is subject of opinion-based abuse.

Sometimes I notice comments like that:

Don't cast the result of malloc

or

Why you don't cast the result of malloc

on questions where OP uses casting. The comments itself contain a hyperlink to this question.

That is in any possible manner inappropriate and incorrect as well. There is no right and no wrong when it is truly a matter of one's own coding-style.


Why is this happening?

It's based upon two reasons:

  1. This question is indeed opinion-based. Technically, the question should have been closed as opinion-based years ago. A "Do I" or "Don't I" or equivalent "Should I" or "Shouldn't I" question, you just can't answer focused without an attitude of one's own opinion. One of the reason to close a question is because it "might lead to opinion-based answers" as it is well shown here.

  2. Many answers (including the most apparent and accepted answer of @unwind) are either completely or almost entirely opinion-based (f.e. a mysterious "clutter" that would be added to your code if you do casting or repeating yourself would be bad) and show a clear and focused tendency to omit the cast. They argue about the redundancy of the cast on one side but also and even worse argue to solve a bug caused by a bug/failure of programming itself - to not #include <stdlib.h> if one want to use malloc().


I want to bring a true view of some points discussed, with less of my personal opinion. A few points need to be noted especially:

  1. Such a very susceptible question to fall into one's own opinion needs an answer with neutral pros and cons. Not only cons or pros.

    A good overview of pros and cons is listed in this answer:

    https://stackoverflow.com/a/33047365/12139179

    (I personally consider this because of that reason the best answer, so far.)


  1. One reason which is encountered at most to reason the omission of the cast is that the cast might hide a bug.

    If someone uses an implicit declared malloc() that returns int (implicit functions are gone from the standard since C99) and sizeof(int) != sizeof(int*), as shown in this question

    Why does this code segfault on 64-bit architecture but work fine on 32-bit?

    the cast would hide a bug.

    While this is true, it only shows half of the story as the omission of the cast would only be a forward-bringing solution to an even bigger bug - not including stdlib.h when using malloc().

    This will never be a serious issue, If you,

    1. Use a compiler compliant to C99 or above (which is recommended and should be mandatory), and

    2. Aren't so absent to forgot to include stdlib.h, when you want to use malloc() in your code, which is a huge bug itself.


  1. Some people argue about C++ compliance of C code, as the cast is obliged in C++.

    First of all to say in general: Compiling C code with a C++ compiler is not a good practice.

    C and C++ are in fact two completely different languages with different semantics.

    But If you really want/need to make C code compliant to C++ and vice versa use compiler switches instead of any cast.

    Since the cast is with tendency declared as redundant or even harmful, I want to take a focus on these questions, which give good reasons why casting can be useful or even necessary:


  1. The cast can be non-beneficial when your code, respectively the type of the assigned pointer (and with that the type of the cast), changes, although this is in most cases unlikely. Then you would need to maintain/change all casts too and if you have a few thousand calls to memory-management functions in your code, this can really summarizing up and decrease the maintenance efficiency.

Summary:

Fact is, that the cast is redundant per the C standard (already since ANSI-C (C89/C90)) if the assigned pointer point to an object of fundamental alignment requirement (which includes the most of all objects).

You don't need to do the cast as the pointer is automatically aligned in this case:

"The order and contiguity of storage allocated by successive calls to the aligned_alloc, calloc, malloc, and realloc functions is unspecified. The pointer returned if the allocation succeeds is suitably aligned so that it may be assigned to a pointer to any type of object with a fundamental alignment requirement and then used to access such an object or an array of such objects in the space allocated (until the space is explicitly deallocated)."

Source: C18, §7.22.3/1


"A fundamental alignment is a valid alignment less than or equal to _Alignof (max_align_t). Fundamental alignments shall be supported by the implementation for objects of all storage durations. The alignment requirements of the following types shall be fundamental alignments:

— all atomic, qualified, or unqualified basic types;

— all atomic, qualified, or unqualified enumerated types;

— all atomic, qualified, or unqualified pointer types;

— all array types whose element type has a fundamental alignment requirement;57)

— all types specified in Clause 7 as complete object types;

— all structure or union types all of whose elements have types with fundamental alignment requirements and none of whose elements have an alignment specifier specifying an alignment that is not a fundamental alignment.

  1. As specified in 6.2.1, the later declaration might hide the prior declaration."

Source: C18, §6.2.8/2

However, if you allocate memory for an implementation-defined object of extended alignment requirement, the cast would be needed.

An extended alignment is represented by an alignment greater than _Alignof (max_align_t). It is implementation-defined whether any extended alignments are supported and the storage durations for which they are supported. A type having an extended alignment requirement is an over-aligned type.58)

Source. C18, §6.2.8/3

Everything else is a matter of the specific use case and one's own opinion.

Please be careful how you educate yourself.

I recommend you to read all of the answers made so far carefully first (as well as their comments which may point at a failure) and then build your own opinion if you or if you not cast the result of malloc() at a specific case.

Please note:

There is no right and wrong answer to that question. It is a matter of style and you yourself decide which way you choose (if you aren't forced to by education or job of course). Please be aware of that and don't let trick you.


Last note: I voted to lately close this question as opinion-based, which is indeed needed since years. If you got the close/reopen privilege I would like to invite you to do so, too.

Android add placeholder text to EditText

If you want to insert text inside your EditText view that stays there after the field is selected (unlike how hint behaves), do this:

In Java:

// Cast Your EditText as a TextView
((TextView) findViewById(R.id.email)).setText("your Text")

In Kotlin:

// Cast your EditText into a TextView
// Like this
(findViewById(R.id.email) as TextView).text = "Your Text"
// Or simply like this
findViewById<TextView>(R.id.email).text = "Your Text"

Resolve conflicts using remote changes when pulling from Git remote

If you truly want to discard the commits you've made locally, i.e. never have them in the history again, you're not asking how to pull - pull means merge, and you don't need to merge. All you need do is this:

# fetch from the default remote, origin
git fetch
# reset your current branch (master) to origin's master
git reset --hard origin/master

I'd personally recommend creating a backup branch at your current HEAD first, so that if you realize this was a bad idea, you haven't lost track of it.

If on the other hand, you want to keep those commits and make it look as though you merged with origin, and cause the merge to keep the versions from origin only, you can use the ours merge strategy:

# fetch from the default remote, origin
git fetch
# create a branch at your current master
git branch old-master
# reset to origin's master
git reset --hard origin/master
# merge your old master, keeping "our" (origin/master's) content
git merge -s ours old-master

(unicode error) 'unicodeescape' codec can't decode bytes in position 2-3: truncated \UXXXXXXXX escape

Try writing the file path as "C:\\Users\miche\Documents\school\jaar2\MIK\2.6\vektis_agb_zorgverlener" i.e with double backslash after the drive as opposed to "C:\Users\miche\Documents\school\jaar2\MIK\2.6\vektis_agb_zorgverlener"

Remove element by id

element.remove()

The DOM is organized in a tree of nodes, where each node has a value, along with a list of references to its child nodes. So element.parentNode.removeChild(element) mimics exactly what is happening internally: First you go the parent node, then remove the reference to the child node.

As of DOM4, a helper function is provided to do the same thing: element.remove(). This works in 96% of browsers (as of 2020), but not IE 11. If you need to support older browsers, you can:

How should I set the default proxy to use default credentials?

From .NET 2.0 you shouldn't need to do this. If you do not explicitly set the Proxy property on a web request it uses the value of the static WebRequest.DefaultWebProxy. If you wanted to change the proxy being used by all subsequent WebRequests, you can set this static DefaultWebProxy property.

The default behaviour of WebRequest.DefaultWebProxy is to use the same underlying settings as used by Internet Explorer.

If you wanted to use different proxy settings to the current user then you would need to code

WebRequest webRequest = WebRequest.Create("http://stackoverflow.com/");
webRequest.Proxy = new WebProxy("http://proxyserver:80/",true);

or

WebRequest.DefaultWebProxy = new WebProxy("http://proxyserver:80/",true);

You should also remember the object model for proxies includes the concept that the proxy can be different depending on the destination hostname. This can make things a bit confusing when debugging and checking the property of webRequest.Proxy. Call

webRequest.Proxy.GetProxy(new Uri("http://google.com.au")) to see the actual details of the proxy server that would be used.

There seems to be some debate about whether you can set webRequest.Proxy or WebRequest.DefaultWebProxy = null to prevent the use of any proxy. This seems to work OK for me but you could set it to new DefaultProxy() with no parameters to get the required behaviour. Another thing to check is that if a proxy element exists in your applications config file, the .NET Framework will NOT use the proxy settings in Internet Explorer.

The MSDN Magazine article Take the Burden Off Users with Automatic Configuration in .NET gives further details of what is happening under the hood.

Endless loop in C/C++

They are the same. But I suggest "while(ture)" which has best representation.

AJAX jQuery refresh div every 5 seconds

you can use this one.

<div id="test"></div>

you java script code should be like that.

setInterval(function(){
      $('#test').load('test.php');
 },5000);

"E: Unable to locate package python-pip" on Ubuntu 18.04

ls /bin/python*

Identify the highest version of python listed. If the highest version is something like python2.7 then install python2-pip If its something like python3.8 then install python3-pip

Example for python3.8:

sudo apt-get install python3-pip

How to query GROUP BY Month in a Year

For MS SQL you can do this.

    select  CAST(DATEPART(MONTH, DateTyme) as VARCHAR) +'/'+ 
CAST(DATEPART(YEAR, DateTyme) as VARCHAR) as 'Date' from #temp
    group by Name, CAST(DATEPART(MONTH, DateTyme) as VARCHAR) +'/'+
 CAST(DATEPART(YEAR, DateTyme) as VARCHAR) 

How to combine date from one field with time from another field - MS SQL Server

I ran into similar situation where I had to merge Date and Time fields to DateTime field. None of the above mentioned solution work, specially adding two fields as the data type for addition of these 2 fields is not same.

I created below solution, where I added hour and then minute part to the date. This worked beautifully for me. Please check it out and do let me know if you get into any issues.

;with tbl as ( select StatusTime = '12/30/1899 5:17:00 PM', StatusDate = '7/24/2019 12:00:00 AM' ) select DATEADD(MI, DATEPART(MINUTE,CAST(tbl.StatusTime AS TIME)),DATEADD(HH, DATEPART(HOUR,CAST(tbl.StatusTime AS TIME)), CAST(tbl.StatusDate as DATETIME))) from tbl

Result: 2019-07-24 17:17:00.000

Specify multiple attribute selectors in CSS

Concatenate the attribute selectors:

input[name="Sex"][value="M"]

Auto-increment on partial primary key with Entity Framework Core

To anyone who came across this question who are using SQL Server Database and still having an exception thrown even after adding the following annotation on the int primary key

[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }

Please check your SQL, make sure your the primary key has 'IDENTITY(startValue, increment)' next to it,

CREATE TABLE [dbo].[User]
(
    [Id] INT IDENTITY(1,1) NOT NULL PRIMARY KEY
)

This will make the database increments the id every time a new row is added, with a starting value of 1 and increments of 1.

I accidentally overlooked that in my SQL which cost me an hour of my life, so hopefully this helps someone!!!

gcc makefile error: "No rule to make target ..."

The problem I found was even sillier than what other folks have mentioned.

Our makefiles get passed lists of things to build. Someone added TheOtherLibrary to one of the lists, as shown below.

LIBRARYDIRS = src/Library
LIBRARYDIRS = src/TheOtherLibrary

They should have done this:

LIBRARYDIRS = src/Library
LIBRARYDIRS += src/TheOtherLibrary

Had they done it the second way, they would not have wiped out the Library build. The plus in += is very important.

How to prevent scanf causing a buffer overflow in C?

If you are using gcc, you can use the GNU-extension a specifier to have scanf() allocate memory for you to hold the input:

int main()
{
  char *str = NULL;

  scanf ("%as", &str);
  if (str) {
      printf("\"%s\"\n", str);
      free(str);
  }
  return 0;
}

Edit: As Jonathan pointed out, you should consult the scanf man pages as the specifier might be different (%m) and you might need to enable certain defines when compiling.

How to get the server path to the web directory in Symfony2 from inside the controller?

My solution is to add this code to the app.php

define('WEB_DIRECTORY', __DIR__);

The problem is that in command line code that uses the constant will break. You can also add the constant to app/console file and the other environment front controllers

Another solution may be add an static method at AppKernel that returns DIR.'/../web/' So you can access everywhere

Difference between window.location.href, window.location.replace and window.location.assign

The part about not being able to use the Back button is a common misinterpretation. window.location.replace(URL) throws out the top ONE entry from the page history list, by overwriting it with the new entry, so the user can't easily go Back to that ONE particular webpage. The function does NOT wipe out the entire page history list, nor does it make the Back button completely non-functional.

(NO function nor combination of parameters that I know of can change or overwrite history list entries that you don't own absolutely for certain - browsers generally impelement this security limitation by simply not even defining any operation that might at all affect any entry other than the top one in the page history list. I shudder to think what sorts of dastardly things malware might do if such a function existed.)

If you really want to make the Back button non-functional (probably not "user friendly": think again if that's really what you want to do), "open" a brand new window. (You can "open" a popup that doesn't even have a "Back" button too ...but popups aren't very popular these days:-) If you want to keep your page showing no matter what the user does (again the "user friendliness" is questionable), set up a window.onunload handler that just reloads your page all over again clear from the very beginning every time.

What's the C# equivalent to the With statement in VB?

Not really, you have to assign a variable. So

    var bar = Stuff.Elements.Foo;
    bar.Name = "Bob Dylan";
    bar.Age = 68;
    bar.Location = "On Tour";
    bar.IsCool = True;

Or in C# 3.0:

    var bar = Stuff.Elements.Foo
    {
        Name = "Bob Dylan",
        Age = 68,
        Location = "On Tour",
        IsCool = True
    };

Scroll to bottom of Div on page load (jQuery)

When page is load then scroll is max value .

This is message box when user send message then always show latest chat in down so that scroll value is always is maxium.

$('#message').scrollTop($('#message')[0].scrollHeight);

see image

Get underlined text with Markdown

In Jupyter Notebooks you can use Markdown in the following way for underlined text. This is similar to HTML5: (<u> and </u>).

<u>Underlined Words Here</u>

How do I import modules or install extensions in PostgreSQL 9.1+?

The extensions available for each version of Postgresql vary. An easy way to check which extensions are available is, as has been already mentioned:

SELECT * FROM pg_available_extensions;

If the extension that you are looking for is available, you can install it using:

CREATE EXTENSION 'extensionName';

or if you want to drop it use:

DROP EXTENSION 'extensionName';

With psql you can additionally check if the extension has been successfully installed using \dx, and find more details about the extension using \dx+ extensioName. It returns additional information about the extension, like which packages are used with it.

If the extension is not available in your Postgres version, then you need to download the necessary binary files and libraries and locate it them at /usr/share/conrib

W3WP.EXE using 100% CPU - where to start?

This is a guess at best, but perhaps your development team is building and deploying the application in debug mode, in stead of release mode. This will cause the occurrence of .pdb files. The implication of this is that your application will take up additional resources to collect system state and debugging information during the execution of your system, causing more processor utilization.

So, it would be simple enough to ensure that they are building and deploying in release mode.

How to delete only the content of file in python

You can do this:

def deleteContent(pfile):
    fn=pfile.name 
    pfile.close()
    return open(fn,'w')

How do I capture response of form.submit

I am not sure that you understand what submit() does...

When you do form1.submit(); the form information is sent to the webserver.

The WebServer will do whatever its supposed to do and return a brand new webpage to the client(usually the same page with something changed).

So, there is no way you can "catch" the return of a form.submit() action.

How can I kill whatever process is using port 8080 so that I can vagrant up?

I needed to run this command

sudo lsof -i :80 # checks port 8080

Then i got

COMMAND   PID USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
acwebseca 312 root   36u  IPv4 0x34ae935da20560c1      0t0  TCP 192.168.1.3:50585->104.25.53.12:http (ESTABLISHED)

show which service is using the PID

ps -ef 312

Then I got this

  UID   PID  PPID   C STIME   TTY           TIME CMD
    0   312    58   0  9:32PM ??         0:02.70 /opt/cisco/anyconnect/bin/acwebsecagent -console

To uninstall cisco web security agent run

sudo /opt/cisco/anyconnect/bin/websecurity_uninstall.sh

credits to: http://tobyaw.livejournal.com/315396.html

Array Size (Length) in C#

You can look at the documentation for Array to find out the answer to this question.

In this particular case you probably need Length:

int sizeOfArray = array.Length;

But since this is such a basic question and you no doubt have many more like this, rather than just telling you the answer I'd rather tell you how to find the answer yourself.

Visual Studio Intellisense

When you type the name of a variable and press the . key it shows you a list of all the methods, properties, events, etc. available on that object. When you highlight a member it gives you a brief description of what it does.

Press F1

If you find a method or property that might do what you want but you're not sure, you can move the cursor over it and press F1 to get help. Here you get a much more detailed description plus links to related information.

Search

The search terms size of array in C# gives many links that tells you the answer to your question and much more. One of the most important skills a programmer must learn is how to find information. It is often faster to find the answer yourself, especially if the same question has been asked before.

Use a tutorial

If you are just beginning to learn C# you will find it easier to follow a tutorial. I can recommend the C# tutorials on MSDN. If you want a book, I'd recommend Essential C#.

Stack Overflow

If you're not able to find the answer on your own, please feel free to post the question on Stack Overflow. But we appreciate it if you show that you have taken the effort to find the answer yourself first.

How to check if a particular service is running on Ubuntu

For centos, below command worked for me (:

locate postgres | grep service

Output:

/usr/lib/firewalld/services/postgresql.xml

/usr/lib/systemd/system/postgresql-9.3.service

sudo systemctl status postgresql-9.3.service

Error: free(): invalid next size (fast):

If you are trying to allocate space for an array of pointers, such as

char** my_array_of_strings;  // or some array of pointers such as int** or even void**

then you will need to consider word size (8 bytes in a 64-bit system, 4 bytes in a 32-bit system) when allocating space for n pointers. The size of a pointer is the same of your word size.

So while you may wish to allocate space for n pointers, you are actually going to need n times 8 or 4 (for 64-bit or 32-bit systems, respectively)

To avoid overflowing your allocated memory for n elements of 8 bytes:

my_array_of_strings = (char**) malloc( n * 8 );  // for 64-bit systems
my_array_of_strings = (char**) malloc( n * 4 );  // for 32-bit systems

This will return a block of n pointers, each consisting of 8 bytes (or 4 bytes if you're using a 32-bit system)

I have noticed that Linux will allow you to use all n pointers when you haven't compensated for word size, but when you try to free that memory it realizes its mistake and it gives out that rather nasty error. And it is a bad one, when you overflow allocated memory, many security issues lie in wait.

Making a WinForms TextBox behave like your browser's address bar

Interestingly, a ComboBox with DropDownStyle=Simple has pretty much exactly the behaviour you are looking for, I think.

(If you reduce the height of the control to not show the list - and then by a couple of pixels more - there's no effective difference between the ComboBox and the TextBox.)

Virtual Serial Port for Linux

I can think of three options:

Implement RFC 2217

RFC 2217 covers a com port to TCP/IP standard that allows a client on one system to emulate a serial port to the local programs, while transparently sending and receiving data and control signals to a server on another system which actually has the serial port. Here's a high-level overview.

What you would do is find or implement a client com port driver that would implement the client side of the system on your PC - appearing to be a real serial port but in reality shuttling everything to a server. You might be able to get this driver for free from Digi, Lantronix, etc in support of their real standalone serial port servers.

You would then implement the server side of the connection locally in another program - allowing the client to connect and issuing the data and control commands as needed.

It's probably non trivial, but the RFC is out there, and you might be able to find an open source project that implements one or both sides of the connection.

Modify the linux serial port driver

Alternately, the serial port driver source for Linux is readily available. Take that, gut the hardware control pieces, and have that one driver run two /dev/ttySx ports, as a simple loopback. Then connect your real program to the ttyS2 and your simulator to the other ttySx.

Use two USB<-->Serial cables in a loopback

But the easiest thing to do right now? Spend $40 on two serial port USB devices, wire them together (null modem) and actually have two real serial ports - one for the program you're testing, one for your simulator.

-Adam

Cannot resolve symbol AppCompatActivity - Support v7 libraries aren't recognized?

After invalidating Cache, changing from

import android.support.v7.app.AppCompatActivity;

to

import androidx.appcompat.app.AppCompatActivity;

worked for me.

How can JavaScript save to a local file?

It all depends on what you are trying to achieve with "saving locally". Do you want to allow the user to download the file? then <a download> is the way to go. Do you want to save it locally, so you can restore your application state? Then you might want to look into the various options of WebStorage. Specifically localStorage or IndexedDB. The FilesystemAPI allows you to create local virtual file systems you can store arbitrary data in.

Find duplicate records in a table using SQL Server

To get the list of multiple records use following command

select field1,field2,field3, count(*)
  from table_name
  group by field1,field2,field3
  having count(*) > 1

Does bootstrap 4 have a built in horizontal divider?

For Bootstrap v4;

for a thin line;

<div class="divider"></div>

for a medium thick line;

<div class="divider py-1 bg-dark"></div>

for a thick line;

<div class="divider py-1 bg-dark"><hr></div>

ERROR 1067 (42000): Invalid default value for 'created_at'

Just convert it by this line :

for the new table :

CREATE TABLE t1 (
  ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
);

for Existing Table:

Alter ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP

Source :

https://dev.mysql.com/doc/refman/5.5/en/timestamp-initialization.html

MomentJS getting JavaScript Date in UTC

A timestamp is a point in time. Typically this can be represented by a number of milliseconds past an epoc (the Unix Epoc of Jan 1 1970 12AM UTC). The format of that point in time depends on the time zone. While it is the same point in time, the "hours value" is not the same among time zones and one must take into account the offset from the UTC.

Here's some code to illustrate. A point is time is captured in three different ways.

var moment = require( 'moment' );

var localDate = new Date();
var localMoment = moment();
var utcMoment = moment.utc();
var utcDate = new Date( utcMoment.format() );

//These are all the same
console.log( 'localData unix = ' + localDate.valueOf() );
console.log( 'localMoment unix = ' + localMoment.valueOf() );
console.log( 'utcMoment unix = ' + utcMoment.valueOf() );

//These formats are different
console.log( 'localDate = ' + localDate );
console.log( 'localMoment string = ' + localMoment.format() );
console.log( 'utcMoment string = ' + utcMoment.format() );
console.log( 'utcDate  = ' + utcDate );

//One to show conversion
console.log( 'localDate as UTC format = ' + moment.utc( localDate ).format() );
console.log( 'localDate as UTC unix = ' + moment.utc( localDate ).valueOf() );

Which outputs this:

localData unix = 1415806206570
localMoment unix = 1415806206570
utcMoment unix = 1415806206570
localDate = Wed Nov 12 2014 10:30:06 GMT-0500 (EST)
localMoment string = 2014-11-12T10:30:06-05:00
utcMoment string = 2014-11-12T15:30:06+00:00
utcDate  = Wed Nov 12 2014 10:30:06 GMT-0500 (EST)
localDate as UTC format = 2014-11-12T15:30:06+00:00
localDate as UTC unix = 1415806206570

In terms of milliseconds, each are the same. It is the exact same point in time (though in some runs, the later millisecond is one higher).

As far as format, each can be represented in a particular timezone. And the formatting of that timezone'd string looks different, for the exact same point in time!

Are you going to compare these time values? Just convert to milliseconds. One value of milliseconds is always less than, equal to or greater than another millisecond value.

Do you want to compare specific 'hour' or 'day' values and worried they "came from" different timezones? Convert to UTC first using moment.utc( existingDate ), and then do operations. Examples of those conversions, when coming out of the DB, are the last console.log calls in the example.

'printf' vs. 'cout' in C++

And I quote:

In high level terms, the main differences are type safety (cstdio doesn't have it), performance (most iostreams implementations are slower than the cstdio ones) and extensibility (iostreams allows custom output targets and seamless output of user defined types).

What is the height of iPhone's onscreen keyboard?

Do remember that, with iOS 8, the onscreen keyboard's size can vary. Don't assume that the onscreen keyboard will always be visible (with a specific height) or invisible.

Now, with iOS 8, the user can also swipe the text-prediction area on and off... and when they do this, it would kick off an app's keyboardWillShow event again.

This will break a lot of legacy code samples, which recommended writing a keyboardWillShow event, which merely measures the current height of the onscreen keyboard, and shifting your controls up or down on the page by this (absolute) amount.

enter image description here

In other words, if you see any sample code, which just tells you to add a keyboardWillShow event, measure the keyboard height, then resize your controls' heights by this amount, this will no longer always work.

In my example above, I used the sample code from the following site, which animates the vertical constraints constant value.

Practicing AutoLayout

In my app, I added a constraint to my UITextView, set to the bottom of the screen. When the screen first appeared, I stored this initial vertical distance.

Then, whenever my keyboardWillShow event gets kicked off, I add the (new) keyboard height to this original constraint value (so the constraint resizes the control's height).

enter image description here

Yeah. It's ugly.

And I'm a little annoyed/surprised that XCode 6's horribly-painful AutoLayout doesn't just allow us to attach the bottoms of controls to either the bottom of the screen, or the top of onscreen keyboard.

Perhaps I'm missing something.

Other than my sanity.

How to use JavaScript to change div backgroundColor

var div = document.getElementById( 'div_id' );
div.onmouseover = function() {
  this.style.backgroundColor = 'green';
  var h2s = this.getElementsByTagName( 'h2' );
  h2s[0].style.backgroundColor = 'blue';
};
div.onmouseout = function() {
  this.style.backgroundColor = 'transparent';
  var h2s = this.getElementsByTagName( 'h2' );
  h2s[0].style.backgroundColor = 'transparent';
};

how does Array.prototype.slice.call() work?

Normally, calling

var b = a.slice();

will copy the array a into b. However, we can't do

var a = arguments.slice();

because arguments isn't a real array, and doesn't have slice as a method. Array.prototype.slice is the slice function for arrays, and call runs the function with this set to arguments.

Cannot find vcvarsall.bat when running a Python script

There is a confusing edge case for this on windows. If you follow the advice to install the 2007 windows, and you still get this error when doing python setup.py install directly, then it may be that the setup.py uses the old version of set up tools.

In particular, the code that points windows towards the right location for the windows installed compiler is in the __init__ method of the setuptools library, which means that you must in your setup.py use the setuptools module. Some older setup.py call methods directly from distutils.core. If this is the case then the setup.py will never find the windows installed compiler. This can be fixed by simply writing import setuptools as the first line of the setup.py file.

Reference: https://bugs.python.org/issue23246: Look about half way down for the quote from steve dower:

Setuptools has the code to find the compiler package. We deliberately put it there instead of in distutils to make sure more people would get it. I should probably port the extra check into 2.7.10, but the immediate fix is to import setuptools.

Should you choose the MONEY or DECIMAL(x,y) datatypes in SQL Server?

We've just come across a very similar issue and I'm now very much a +1 for never using Money except in top level presentation. We have multiple tables (effectively a sales voucher and sales invoice) each of which contains one or more Money fields for historical reasons, and we need to perform a pro-rata calculation to work out how much of the total invoice Tax is relevant to each line on the sales voucher. Our calculation is

vat proportion = total invoice vat x (voucher line value / total invoice value)

This results in a real world money / money calculation which causes scale errors on the division part, which then multiplies up into an incorrect vat proportion. When these values are subsequently added, we end up with a sum of the vat proportions which do not add up to the total invoice value. Had either of the values in the brackets been a decimal (I'm about to cast one of them as such) the vat proportion would be correct.

When the brackets weren't there originally this used to work, I guess because of the larger values involved, it was effectively simulating a higher scale. We added the brackets because it was doing the multiplication first, which was in some rare cases blowing the precision available for the calculation, but this has now caused this much more common error.

What's the difference between an argument and a parameter?

The parameters of a function/method describe to you the values that it uses to calculate its result.

The arguments of a function are the values assigned to these parameters during a particular call of the function/method.

Correct way to populate an Array with a Range in Ruby

This works for me in irb:

irb> (1..4).to_a
=> [1, 2, 3, 4]

I notice that:

irb> 1..4.to_a
(irb):1: warning: default `to_a' will be obsolete
ArgumentError: bad value for range
        from (irb):1

So perhaps you are missing the parentheses?

(I am running Ruby 1.8.6 patchlevel 114)

Adding items to an object through the .push() method

Another way of doing it would be:

stuff = Object.assign(stuff, {$(this).attr('value'):$(this).attr('checked')});

Read more here: Object.assign()

Disable submit button ONLY after submit

Reading the comments, it seems that these solutions are not consistent across browsers. Decided then to think how I would have done this 10 years ago before the advent of jQuery and event function binding.

So here is my retro hipster solution:

<script type="text/javascript">
var _formConfirm_submitted = false;
</script>
<form name="frmConfirm" onsubmit="if( _formConfirm_submitted == false ){ _formConfirm_submitted = true;return true }else{ alert('your request is being processed!'); return false;  }" action="" method="GET">

<input type="submit" value="submit - but only once!"/>
</form>

The main point of difference is that I am relying on the ability to stop a form submitting through returning false on the submit handler, and I am using a global flag variable - which will make me go straight to hell!

But on the plus side, I cannot imagine any browser compatibility issues - hey, it would probably even work in Netscape!

Setting Authorization Header of HttpClient

In net .core you can use

var client = new HttpClient();
client.SetBasicAuthentication(userName, password);

or

var client = new HttpClient();
client.SetBearerToken(token);

Facebook Architecture

"Knowing about sites which handles such massive traffic gives lots of pointers for architects etc. to keep in mind certain stuff while designing new sites"

I think you can probably learn a lot from the design of Facebook, just as you can from the design of any successful large software system. However, it seems to me that you should not keep the current design of Facebook in mind when designing new systems.

Why do you want to be able to handle the traffic that Facebook has to handle? Odds are that you will never have to, no matter how talented a programmer you may be. Facebook itself was not designed from the start for such massive scalability, which is perhaps the most important lesson to learn from it.

If you want to learn about a non-trivial software system I can recommend the book "Dissecting a C# Application" about the development of the SharpDevelop IDE. It is out of print, but it is available for free online. The book gives you a glimpse into a real application and provides insights about IDEs which are useful for a programmer.

Enabling/installing GD extension? --without-gd

I've PHP 7.3 and Nginx 1.14 on Ubuntu 18.

# it installs php7.3-gd for the moment
# and restarts PHP 7.3 FastCGI Process Manager: php-fpm7.3.
sudo apt-get install php-gd

# after I've restarted Nginx
sudo /etc/init.d/nginx restart

Works!

What's the proper value for a checked attribute of an HTML checkbox?

  1. checked
  2. checked=""
  3. checked="checked"

    are equivalent;


according to spec checkbox '----? checked = "checked" or "" (empty string) or empty Specifies that the element represents a selected control.---'

How to print a date in a regular format?

from datetime import date
def time-format():
  return str(date.today())
print (time-format())

this will print 6-23-2018 if that's what you want :)

The localhost page isn’t working localhost is currently unable to handle this request. HTTP ERROR 500

It maybe solve your problem, check your files access level

$ sudo chmod -R 777 /"your files location"

How to efficiently concatenate strings in go

If you know the total length of the string that you're going to preallocate then the most efficient way to concatenate strings may be using the builtin function copy. If you don't know the total length before hand, do not use copy, and read the other answers instead.

In my tests, that approach is ~3x faster than using bytes.Buffer and much much faster (~12,000x) than using the operator +. Also, it uses less memory.

I've created a test case to prove this and here are the results:

BenchmarkConcat  1000000    64497 ns/op   502018 B/op   0 allocs/op
BenchmarkBuffer  100000000  15.5  ns/op   2 B/op        0 allocs/op
BenchmarkCopy    500000000  5.39  ns/op   0 B/op        0 allocs/op

Below is code for testing:

package main

import (
    "bytes"
    "strings"
    "testing"
)

func BenchmarkConcat(b *testing.B) {
    var str string
    for n := 0; n < b.N; n++ {
        str += "x"
    }
    b.StopTimer()

    if s := strings.Repeat("x", b.N); str != s {
        b.Errorf("unexpected result; got=%s, want=%s", str, s)
    }
}

func BenchmarkBuffer(b *testing.B) {
    var buffer bytes.Buffer
    for n := 0; n < b.N; n++ {
        buffer.WriteString("x")
    }
    b.StopTimer()

    if s := strings.Repeat("x", b.N); buffer.String() != s {
        b.Errorf("unexpected result; got=%s, want=%s", buffer.String(), s)
    }
}

func BenchmarkCopy(b *testing.B) {
    bs := make([]byte, b.N)
    bl := 0

    b.ResetTimer()
    for n := 0; n < b.N; n++ {
        bl += copy(bs[bl:], "x")
    }
    b.StopTimer()

    if s := strings.Repeat("x", b.N); string(bs) != s {
        b.Errorf("unexpected result; got=%s, want=%s", string(bs), s)
    }
}

// Go 1.10
func BenchmarkStringBuilder(b *testing.B) {
    var strBuilder strings.Builder

    b.ResetTimer()
    for n := 0; n < b.N; n++ {
        strBuilder.WriteString("x")
    }
    b.StopTimer()

    if s := strings.Repeat("x", b.N); strBuilder.String() != s {
        b.Errorf("unexpected result; got=%s, want=%s", strBuilder.String(), s)
    }
}

multiple prints on the same line in Python

Just in case you have pre-stored the values in an array, you can call them in the following format:

for i in range(0,n):
       print arr[i],

git status shows fatal: bad object HEAD

I solved this by doing git fetch. My error was because I moved my file from my main storage to my secondary storage on windows 10.

About .bash_profile, .bashrc, and where should alias be written in?

From the bash manpage:

When bash is invoked as an interactive login shell, or as a non-interactive shell with the --login option, it first reads and executes commands from the file /etc/profile, if that file exists. After reading that file, it looks for ~/.bash_profile, ~/.bash_login, and ~/.profile, in that order, and reads and executes commands from the first one that exists and is readable. The --noprofile option may be used when the shell is started to inhibit this behavior.

When a login shell exits, bash reads and executes commands from the file ~/.bash_logout, if it exists.

When an interactive shell that is not a login shell is started, bash reads and executes commands from ~/.bashrc, if that file exists. This may be inhibited by using the --norc option. The --rcfile file option will force bash to read and execute commands from file instead of ~/.bashrc.

Thus, if you want to get the same behavior for both login shells and interactive non-login shells, you should put all of your commands in either .bashrc or .bash_profile, and then have the other file source the first one.

Increase days to php current Date()

$NewTime = mktime(date('G'), date('i'), date('s'), date('n'), date('j') + $DaysToAdd, date('Y'));

From mktime documentation:

mktime() is useful for doing date arithmetic and validation, as it will automatically calculate the correct value for out-of-range input.

The advantage of this method is that you can add or subtract any time interval (hours, minutes, seconds, days, months, or years) in an easy to read line of code.

Beware there is a tradeoff in performance, as this code is about 2.5x slower than strtotime("+1 day") due to all the calls to the date() function. Consider re-using those values if you are in a loop.

C++: variable 'std::ifstream ifs' has initializer but incomplete type

This seems to be answered - #include <fstream>.

The message means :-

incomplete type - the class has not been defined with a full class. The compiler has seen statements such as class ifstream; which allow it to understand that a class exists, but does not know how much memory the class takes up.

The forward declaration allows the compiler to make more sense of :-

void BindInput( ifstream & inputChannel ); 

It understands the class exists, and can send pointers and references through code without being able to create the class, see any data within the class, or call any methods of the class.

The has initializer seems a bit extraneous, but is saying that the incomplete object is being created.

Java: Date from unix timestamp

Date's constructor expects the timeStamp value to be in milliseconds. Multiply your timestamp's value with 1000, then pass it to the constructor.

How can I disable the bootstrap hover color for links?

For me none of the simple solutions above worked, however by changing only the hover I was able to get it to work:

  :hover {
    color: inherit;
    text-decoration: none;
  }

How can I center a div within another div?

To make a div in center. There isn't any need to assign the width of the div.

A working demo is here:

http://jsfiddle.net/6yukdmwq/

    .container {
        width: 100%;
        height: 500px;
        display: table;
        border: 1px solid red;
        text-align: center;}

    .center {
        display: table-cell;
        vertical-align: middle;
    }

    .content {
        display: inline-block;
        text-align: center;
        border: 1px solid green;
    }
    <section class="container">
        <div class="center">
            <div class="content">
                <h1>Helllo Center Text</h1>
            </div>
        </div>
    </section>

How to parse XML using vba

Update

The procedure presented below gives an example of parsing XML with VBA using the XML DOM objects. Code is based on a beginners guide of the XML DOM.

Public Sub LoadDocument()
    Dim xDoc As MSXML.DOMDocument
    Set xDoc = New MSXML.DOMDocument
    xDoc.validateOnParse = False
    If xDoc.Load("C:\My Documents\sample.xml") Then
        ' The document loaded successfully.
        ' Now do something intersting.
        DisplayNode xDoc.childNodes, 0
    Else
        ' The document failed to load.
        ' See the previous listing for error information.
    End If
End Sub

Public Sub DisplayNode(ByRef Nodes As MSXML.IXMLDOMNodeList, _
   ByVal Indent As Integer)

   Dim xNode As MSXML.IXMLDOMNode
   Indent = Indent + 2

   For Each xNode In Nodes
      If xNode.nodeType = NODE_TEXT Then
         Debug.Print Space$(Indent) & xNode.parentNode.nodeName & _
            ":" & xNode.nodeValue
      End If

      If xNode.hasChildNodes Then
         DisplayNode xNode.childNodes, Indent
      End If
   Next xNode
End Sub

Nota Bene - This initial answer shows the simplest possible thing I could imagine (at the time I was working on a very specific issue) . Naturally using the XML facilities built into the VBA XML Dom would be much better. See the updates above.

Original Response

I know this is a very old post but I wanted to share my simple solution to this complicated question. Primarily I've used basic string functions to access the xml data.

This assumes you have some xml data (in the temp variable) that has been returned within a VBA function. Interestingly enough one can also see how I am linking to an xml web service to retrieve the value. The function shown in the image also takes a lookup value because this Excel VBA function can be accessed from within a cell using = FunctionName(value1, value2) to return values via the web service into a spreadsheet.

sample function


openTag = ""
closeTag = "" 

' Locate the position of the enclosing tags startPos = InStr(1, temp, openTag) endPos = InStr(1, temp, closeTag) startTagPos = InStr(startPos, temp, ">") + 1 ' Parse xml for returned value Data = Mid(temp, startTagPos, endPos - startTagPos)

Easier way to debug a Windows service

This YouTube video by Fabio Scopel explains how to debug a Windows service quite nicely... the actual method of doing it starts at 4:45 in the video...

Here is the code explained in the video... in your Program.cs file, add the stuff for the Debug section...

namespace YourNamespace
{
    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        static void Main()
        {
#if DEBUG
            Service1 myService = new Service1();
            myService.OnDebug();
            System.Threading.Thread.Sleep(System.Threading.Timeout.Infinite);
#else
            ServiceBase[] ServicesToRun;
            ServicesToRun = new ServiceBase[]
            {
                new Service1()
            };
            ServiceBase.Run(ServicesToRun);
#endif

        }
    }
}

In your Service1.cs file, add the OnDebug() method...

    public Service1()
    {
        InitializeComponent();
    }

    public void OnDebug()
    {
        OnStart(null);
    }

    protected override void OnStart(string[] args)
    {
        // your code to do something
    }

    protected override void OnStop()
    {
    }

How it works

Basically you have to create a public void OnDebug() that calls the OnStart(string[] args) as it's protected and not accessible outside. The void Main() program is added with #if preprocessor with #DEBUG.

Visual Studio defines DEBUG if project is compiled in Debug mode.This will allow the debug section(below) to execute when the condition is true

Service1 myService = new Service1();
myService.OnDebug();
System.Threading.Thread.Sleep(System.Threading.Timeout.Infinite);

And it will run just like a console application, once things go OK you can change the mode Release and the regular else section will trigger the logic

REST - HTTP Post Multipart with JSON

If I understand you correctly, you want to compose a multipart request manually from an HTTP/REST console. The multipart format is simple; a brief introduction can be found in the HTML 4.01 spec. You need to come up with a boundary, which is a string not found in the content, let’s say HereGoes. You set request header Content-Type: multipart/form-data; boundary=HereGoes. Then this should be a valid request body:

--HereGoes
Content-Disposition: form-data; name="myJsonString"
Content-Type: application/json

{"foo": "bar"}
--HereGoes
Content-Disposition: form-data; name="photo"
Content-Type: image/jpeg
Content-Transfer-Encoding: base64

<...JPEG content in base64...>
--HereGoes--

jQuery onclick event for <li> tags

I'm not really sure what your question is, but to get the text of the li element you can use:

$(this).text();

And to get the id of an element you can use .attr('id');. Once you have a reference to the element you want (e.g. $(this)) you can perform any jQuery function on it.

Changing cursor to waiting in javascript/jquery

You don't need JavaScript for this. You can change the cursor to anything you want using CSS :

selector {
    cursor: url(myimage.jpg), auto;
}

See here for browser support as there are some subtle differences depending on browser

php_network_getaddresses: getaddrinfo failed: Name or service not known

Had such a problem (with https://github.com/PHPMailer/PHPMailer), just reload PHP and everything start worked

for Centos 6 and 7:

service php-fpm restart 

Can I disable a CSS :hover effect via JavaScript?

Actually an other way to solve this could be, overwriting the CSS with insertRule.

It gives the ability to inject CSS rules to an existing/new stylesheet. In my concrete example it would look like this:

//creates a new `style` element in the document
var sheet = (function(){
  var style = document.createElement("style");
  // WebKit hack :(
  style.appendChild(document.createTextNode(""));
  // Add the <style> element to the page
  document.head.appendChild(style);
  return style.sheet;
})();

//add the actual rules to it
sheet.insertRule(
 "ul#mainFilter a:hover { color: #0000EE }" , 0
);

Demo with my 4 years old original example: http://jsfiddle.net/raPeX/21/

Numpy AttributeError: 'float' object has no attribute 'exp'

You convert type np.dot(X, T) to float32 like this:

z=np.array(np.dot(X, T),dtype=np.float32)

def sigmoid(X, T):
    return (1.0 / (1.0 + np.exp(-z)))

Hopefully it will finally work!

Don't reload application when orientation changes

It's my experience that it's actually better to just deal with the orientation changes properly instead of trying to shoehorn a non-default behavior.

You should save the image that's currently being displayed in onSaveInstanceState() and restore it properly when your application runs through onCreate() again.

http://localhost:8080/ Access Error: 404 -- Not Found Cannot locate document: /

your 8080 port is already used by another application 1/ you can try to find out which app is using it, using "netstat -aon" and stop the process; 2/ you can go to server.xml and change from port 8080 to another one (ex: 8081)

"No cached version... available for offline mode."

With the new Android Studio 3.6 to toggle Gradle's offline mode go to View > Tool Windows > Gradle from the menu bar and toggle the value of Offline Mode that is near the top of the Gradle window.

enter image description here

enter image description here

Create a hexadecimal colour based on a string with JavaScript

This function does the trick. It's an adaptation of this, fairly longer implementation this repo ..

const color = (str) => {
    let rgb = [];
    // Changing non-hexadecimal characters to 0
    str = [...str].map(c => (/[0-9A-Fa-f]/g.test(c)) ? c : 0).join('');
    // Padding string with zeroes until it adds up to 3
    while (str.length % 3) str += '0';

    // Dividing string into 3 equally large arrays
    for (i = 0; i < str.length; i += str.length / 3)
        rgb.push(str.slice(i, i + str.length / 3));

    // Formatting a hex color from the first two letters of each portion
    return `#${rgb.map(string => string.slice(0, 2)).join('')}`;
}

What's the difference between a null pointer and a void pointer?

A null pointer points has the value NULL which is typically 0, but in any case a memory location which is invalid to dereference. A void pointer points at data of type void. The word "void" is not an indication that the data referenced by the pointer is invalid or that the pointer has been nullified.

How to mock void methods with Mockito

The solution of so-called problem is to use a spy Mockito.spy(...) instead of a mock Mockito.mock(..).

Spy enables us to partial mocking. Mockito is good at this matter. Because you have class which is not complete, in this way you mock some required place in this class.

Make .gitignore ignore everything except a few files

This is how I keep the structure of folders while ignoring everything else. You have to have a README.md file in each directory (or .gitkeep).

/data/*
!/data/README.md

!/data/input/
/data/input/*
!/data/input/README.md

!/data/output/
/data/output/*
!/data/output/README.md

Differences between key, superkey, minimal superkey, candidate key and primary key

Largely based on the accepted answer, but with a few tweaks to fit better the definitions taught in some courses:

  • Key: A set of = 1 columns.
  • Superkey: A key that ? a candidate key.
    • Therefore, a superkey must contain > 1 columns.
    • Minimal Super key = Candidate Key: A key that can uniquely identify each row in a table.
    • Primary Key: The chosen Candidate Key for doing that.
    • Secondary key / Alternate key: A Candidate Key not chosen for doing that.
  • Search Key: A key used for locating records.
  • Composite key or concatenate key: A key with > 1 columns.
    • Usually implies "composite primary key", although "composite alternate key" is also a thing.
  • Sort or control key: A key used to physically sequence the stored data.
  • Foreign Key A key in one table that matches the Primary Key of another table.
    • The table in which foreign key resides is called as dependent table.
    • The table to which foreign key refers is known as parent table.

How to get past the login page with Wget?

I wanted a one-liner that didn't download any files; here is an example of piping the cookie output into the next request. I only tested the following on Gentoo, but it should work in most *nix environments:

wget -q -O /dev/null --save-cookies /dev/stdout --post-data 'u=user&p=pass' 'http://example.com/login' | wget -q -O - --load-cookies /dev/stdin 'http://example.com/private/page'

(This is one line, though it likely wraps on your browser)

If you want the output saved to a file, change -O - to -O /some/file/name.ext

How can I turn a JSONArray into a JSONObject?

Can't you originally get the data as a JSONObject?

Perhaps parse the string as both a JSONObject and a JSONArray in the first place? Where is the JSON string coming from?

I'm not sure that it is possible to convert a JsonArray into a JsonObject.

I presume you are using the following from json.org

  • JSONObject.java
    A JSONObject is an unordered collection of name/value pairs. Its external form is a string wrapped in curly braces with colons between the names and values, and commas between the values and names. The internal form is an object having get() and opt() methods for accessing the values by name, and put() methods for adding or replacing values by name. The values can be any of these types: Boolean, JSONArray, JSONObject, Number, and String, or the JSONObject.NULL object.

  • JSONArray.java
    A JSONArray is an ordered sequence of values. Its external form is a string wrapped in square brackets with commas between the values. The internal form is an object having get() and opt() methods for accessing the values by index, and put() methods for adding or replacing values. The values can be any of these types: Boolean, JSONArray, JSONObject, Number, and String, or the JSONObject.NULL object.

Temporary tables in stored procedures

The database uses the same lock for all #temp tables so if you are using a lot you will get deadlock problems. It is better to use @ table variables for concurrency.

Where can I get a list of Ansible pre-defined variables?

Argh! From the FAQ:

How do I see a list of all of the ansible_ variables? Ansible by default gathers “facts” about the machines under management, and these facts can be accessed in Playbooks and in templates. To see a list of all of the facts that are available about a machine, you can run the “setup” module as an ad-hoc action:

ansible -m setup hostname

This will print out a dictionary of all of the facts that are available for that particular host.

Here is the output for my vagrant virtual machine called scdev:

scdev | success >> {
    "ansible_facts": {                                                                                                 
        "ansible_all_ipv4_addresses": [                                                                                
            "10.0.2.15",                                                                                               
            "192.168.10.10"                                                                                            
        ],                                                                                                             
        "ansible_all_ipv6_addresses": [                                                                                
            "fe80::a00:27ff:fe12:9698",                                                                                
            "fe80::a00:27ff:fe74:1330"                                                                                 
        ],                                                                                                             
        "ansible_architecture": "i386",                                                                                
        "ansible_bios_date": "12/01/2006",                                                                             
        "ansible_bios_version": "VirtualBox",                                                                          
        "ansible_cmdline": {                                                                                           
            "BOOT_IMAGE": "/vmlinuz-3.2.0-23-generic-pae",                                                             
            "quiet": true,                                                                                             
            "ro": true,                                                                                                
            "root": "/dev/mapper/precise32-root"                                                                       
        },                                                                                                             
        "ansible_date_time": {                                                                                         
            "date": "2013-09-17",                                                                                      
            "day": "17",                                                                                               
            "epoch": "1379378304",                                                                                     
            "hour": "00",                                                                                              
            "iso8601": "2013-09-17T00:38:24Z",                                                                         
            "iso8601_micro": "2013-09-17T00:38:24.425092Z",                                                            
            "minute": "38",                                                                                            
            "month": "09",                                                                                             
            "second": "24",                                                                                            
            "time": "00:38:24",                                                                                        
            "tz": "UTC",                                                                                               
            "year": "2013"                                                                                             
        },                                                                                                             
        "ansible_default_ipv4": {                                                                                      
            "address": "10.0.2.15",                                                                                    
            "alias": "eth0",                                                                                           
            "gateway": "10.0.2.2",                                                                                     
            "interface": "eth0",                                                                                       
            "macaddress": "08:00:27:12:96:98",                                                                         
            "mtu": 1500,                                                                                               
            "netmask": "255.255.255.0",                                                                                
            "network": "10.0.2.0",                                                                                     
            "type": "ether"                                                                                            
        },                                                                                                             
        "ansible_default_ipv6": {},                                                                                    
        "ansible_devices": {                                                                                           
            "sda": {                                                                                                   
                "holders": [],                                                                                         
                "host": "SATA controller: Intel Corporation 82801HM/HEM (ICH8M/ICH8M-E) SATA Controller [AHCI mode] (rev 02)",                                                                                                                
                "model": "VBOX HARDDISK",                                                                              
                "partitions": {                                                                                        
                    "sda1": {                                                                                          
                        "sectors": "497664",                                                                           
                        "sectorsize": 512,                                                                             
                        "size": "243.00 MB",                                                                           
                        "start": "2048"                                                                                
                    },                                                                                                 
                    "sda2": {                                                                                          
                        "sectors": "2",                                                                                
                        "sectorsize": 512,                                                                             
                        "size": "1.00 KB",                                                                             
                        "start": "501758"                                                                              
                    },                                                                                                 
                },                                                                                                     
                "removable": "0",                                                                                      
                "rotational": "1",                                                                                     
                "scheduler_mode": "cfq",                                                                               
                "sectors": "167772160",                                                                                
                "sectorsize": "512",                                                                                   
                "size": "80.00 GB",                                                                                    
                "support_discard": "0",                                                                                
                "vendor": "ATA"                                                                                        
            },                                                                                                         
            "sr0": {                                                                                                   
                "holders": [],                                                                                         
                "host": "IDE interface: Intel Corporation 82371AB/EB/MB PIIX4 IDE (rev 01)",                           
                "model": "CD-ROM",                                                                                     
                "partitions": {},                                                                                      
                "removable": "1",                                                                                      
                "rotational": "1",                                                                                     
                "scheduler_mode": "cfq",                                                                               
                "sectors": "2097151",                                                                                  
                "sectorsize": "512",                                                                                   
                "size": "1024.00 MB",                                                                                  
                "support_discard": "0",                                                                                
                "vendor": "VBOX"                                                                                       
            },                                                                                                         
            "sr1": {                                                                                                   
                "holders": [],                                                                                         
                "host": "IDE interface: Intel Corporation 82371AB/EB/MB PIIX4 IDE (rev 01)",                           
                "model": "CD-ROM",                                                                                     
                "partitions": {},                                                                                      
                "removable": "1",                                                                                      
                "rotational": "1",                                                                                     
                "scheduler_mode": "cfq",                                                                               
                "sectors": "2097151",                                                                                  
                "sectorsize": "512",                                                                                   
                "size": "1024.00 MB",                                                                                  
                "support_discard": "0",                                                                                
                "vendor": "VBOX"                                                                                       
            }                                                                                                          
        },                                                                                                             
        "ansible_distribution": "Ubuntu",                                                                              
        "ansible_distribution_release": "precise",                                                                     
        "ansible_distribution_version": "12.04",                                                                       
        "ansible_domain": "",                                                                                          
        "ansible_eth0": {                                                                                              
            "active": true,                                                                                            
            "device": "eth0",                                                                                          
            "ipv4": {                                                                                                  
                "address": "10.0.2.15",                                                                                
                "netmask": "255.255.255.0",                                                                            
                "network": "10.0.2.0"                                                                                  
            },                                                                                                         
            "ipv6": [                                                                                                  
                {                                                                                                      
                    "address": "fe80::a00:27ff:fe12:9698",                                                             
                    "prefix": "64",                                                                                    
                    "scope": "link"                                                                                    
                }                                                                                                      
            ],                                                                                                         
            "macaddress": "08:00:27:12:96:98",                                                                         
            "module": "e1000",                                                                                         
            "mtu": 1500,                                                                                               
            "type": "ether"                                                                                            
        },                                                                                                             
        "ansible_eth1": {                                                                                              
            "active": true,                                                                                            
            "device": "eth1",                                                                                          
            "ipv4": {                                                                                                  
                "address": "192.168.10.10",                                                                            
                "netmask": "255.255.255.0",                                                                            
                "network": "192.168.10.0"                                                                              
            },                                                                                                         
            "ipv6": [                                                                                                  
                {                                                                                                      
                    "address": "fe80::a00:27ff:fe74:1330",                                                             
                    "prefix": "64",                                                                                    
                    "scope": "link"                                                                                    
                }                                                                                                      
            ],                                                                                                         
            "macaddress": "08:00:27:74:13:30",                                                                         
            "module": "e1000",                                                                                         
            "mtu": 1500,                                                                                               
            "type": "ether"                                                                                            
        },                                                                                                             
        "ansible_form_factor": "Other",                                                                                
        "ansible_fqdn": "scdev",                                                                                       
        "ansible_hostname": "scdev",                                                                                   
        "ansible_interfaces": [                                                                                        
            "lo",                                                                                                      
            "eth1",                                                                                                    
            "eth0"                                                                                                     
        ],                                                                                                             
        "ansible_kernel": "3.2.0-23-generic-pae",                                                                      
        "ansible_lo": {                                                                                                
            "active": true,                                                                                            
            "device": "lo",                                                                                            
            "ipv4": {                                                                                                  
                "address": "127.0.0.1",                                                                                
                "netmask": "255.0.0.0",                                                                                
                "network": "127.0.0.0"                                                                                 
            },                                                                                                         
            "ipv6": [                                                                                                  
                {                                                                                                      
                    "address": "::1",                                                                                  
                    "prefix": "128",                                                                                   
                    "scope": "host"                                                                                    
                }                                                                                                      
            ],                                                                                                         
            "mtu": 16436,                                                                                              
            "type": "loopback"                                                                                         
        },                                                                                                             
        "ansible_lsb": {                                                                                               
            "codename": "precise",                                                                                     
            "description": "Ubuntu 12.04 LTS",                                                                         
            "id": "Ubuntu",                                                                                            
            "major_release": "12",                                                                                     
            "release": "12.04"                                                                                         
        },                                                                                                             
        "ansible_machine": "i686",                                                                                     
        "ansible_memfree_mb": 23,                                                                                      
        "ansible_memtotal_mb": 369,                                                                                    
        "ansible_mounts": [                                                                                            
            {                                                                                                          
                "device": "/dev/mapper/precise32-root",                                                                
                "fstype": "ext4",                                                                                      
                "mount": "/",                                                                                          
                "options": "rw,errors=remount-ro",                                                                     
                "size_available": 77685088256,                                                                         
                "size_total": 84696281088                                                                              
            },                                                                                                         
            {                                                                                                          
                "device": "/dev/sda1",                                                                                 
                "fstype": "ext2",                                                                                      
                "mount": "/boot",                                                                                      
                "options": "rw",                                                                                       
                "size_available": 201044992,                                                                           
                "size_total": 238787584                                                                                
            },                                                                                                         
            {                                                                                                          
                "device": "/vagrant",                                                                                  
                "fstype": "vboxsf",                                                                                    
                "mount": "/vagrant",                                                                                   
                "options": "uid=1000,gid=1000,rw",                                                                     
                "size_available": 42013151232,                                                                         
                "size_total": 484145360896                                                                             
            }                                                                                                          
        ],                                                                                                             
        "ansible_os_family": "Debian",                                                                                 
        "ansible_pkg_mgr": "apt",                                                                                      
        "ansible_processor": [                                                                                         
            "Pentium(R) Dual-Core  CPU      E5300  @ 2.60GHz"                                                          
        ],                                                                                                             
        "ansible_processor_cores": "NA",                                                                               
        "ansible_processor_count": 1,                                                                                  
        "ansible_product_name": "VirtualBox",                                                                          
        "ansible_product_serial": "NA",                                                                                
        "ansible_product_uuid": "NA",                                                                                  
        "ansible_product_version": "1.2",                                                                              
        "ansible_python_version": "2.7.3", 
        "ansible_selinux": false, 
        "ansible_swapfree_mb": 766, 
        "ansible_swaptotal_mb": 767, 
        "ansible_system": "Linux", 
        "ansible_system_vendor": "innotek GmbH", 
        "ansible_user_id": "neves", 
        "ansible_userspace_architecture": "i386", 
        "ansible_userspace_bits": "32", 
        "ansible_virtualization_role": "guest", 
        "ansible_virtualization_type": "virtualbox"
    }, 
    "changed": false
}

The current documentation now has a complete chapter listing all Variables and Facts

Using a SELECT statement within a WHERE clause

There's a much better way to achieve your desired result, using SQL Server's analytic (or windowing) functions.

SELECT DISTINCT Date, MAX(Score) OVER(PARTITION BY Date) FROM ScoresTable

If you need more than just the date and max score combinations, you can use ranking functions, eg:

SELECT  *
FROM    ScoresTable t
JOIN (   
    SELECT 
        ScoreId,
        ROW_NUMBER() OVER (PARTITION BY Date ORDER BY Score DESC) AS [Rank] 
        FROM ScoresTable
) window ON window.ScoreId = p.ScoreId AND window.[Rank] = 1

You may want to use RANK() instead of ROW_NUMBER() if you want multiple records to be returned if they both share the same MAX(Score).

Javascript : get <img> src and set as variable?

If you don't have an id on the image but have a parent div this is also a technique you can use.

<div id="myDiv"><img src="http://www.example.com/image.png"></div>

var myVar = document.querySelectorAll('#myDiv img')[0].src

Using print statements only to debug

I don't know about others, but I was used to define a "global constant" (DEBUG) and then a global function (debug(msg)) that would print msg only if DEBUG == True.

Then I write my debug statements like:

debug('My value: %d' % value)

...then I pick up unit testing and never did this again! :)

Combine two ActiveRecord::Relation objects

merge actually doesn't work like OR. It's simply intersection (AND)

I struggled with this problem to combine to ActiveRecord::Relation objects into one and I didn't found any working solution for me.

Instead of searching for right method creating an union from these two sets, I focused on algebra of sets. You can do it in different way using De Morgan's law

ActiveRecord provides merge method (AND) and also you can use not method or none_of (NOT).

search.where.none_of(search.where.not(id: ids_to_exclude).merge(search.where.not("title ILIKE ?", "%#{query}%")))

You have here (A u B)' = A' ^ B'

UPDATE: The solution above is good for more complex cases. In your case smth like that will be enough:

User.where('first_name LIKE ? OR last_name LIKE ?', 'Tobias', 'Fünke')

Does height and width not apply to span?

Try using a div instead of the span or using the CSS display: block; or display: inline-block;span is by default an inline element which cannot take width and height properties.

Clearing <input type='file' /> using jQuery

Make it asynchronous, and reset it after the button's desired actions have been done.

    <!-- Html Markup --->
    <input id="btn" type="file" value="Button" onchange="function()" />

    <script>
    //Function
    function function(e) {

        //input your coding here           

        //Reset
        var controlInput = $("#btn");
        controlInput.replaceWith(controlInput = controlInput.val('').clone(true));
    } 
    </script>

How to compare character ignoring case in primitive types

Generic methods to compare a char at a position between 2 strings with ignore case.

public static boolean isEqualIngoreCase(char one, char two){
    return Character.toLowerCase(one)==Character .toLowerCase(two);
}

public static boolean isEqualStringCharIgnoreCase(String one, String two, int position){
    char oneChar = one.charAt(position);
    char twoChar = two.charAt(position);
    return isEqualIngoreCase(oneChar, twoChar);
}

Function call

boolean isFirstCharEqual = isEqualStringCharIgnoreCase("abc", "ABC", 0)

Unable to run Java GUI programs with Ubuntu

I stopped getting this exception when I installed default-jdk using apt. I'm running Ubuntu 14.04 (Trusty Tahr), and the problem appears to have been the result of having a "headless" Java installed. All I did was:

sudo apt-get install default-jdk

How to start working with GTest and CMake

The solution involved putting the gtest source directory as a subdirectory of your project. I've included the working CMakeLists.txt below if it is helpful to anyone.

cmake_minimum_required(VERSION 2.6)
project(basic_test)

################################
# GTest
################################
ADD_SUBDIRECTORY (gtest-1.6.0)
enable_testing()
include_directories(${gtest_SOURCE_DIR}/include ${gtest_SOURCE_DIR})

################################
# Unit Tests
################################
# Add test cpp file
add_executable( runUnitTests testgtest.cpp )
# Link test executable against gtest & gtest_main
target_link_libraries(runUnitTests gtest gtest_main)
add_test( runUnitTests runUnitTests )

What is the use of <<<EOD in PHP?

there are four types of strings available in php. They are single quotes ('), double quotes (") and Nowdoc (<<<'EOD') and heredoc(<<<EOD) strings

you can use both single quotes and double quotes inside heredoc string. Variables will be expanded just as double quotes.

nowdoc strings will not expand variables just like single quotes.

ref: http://www.php.net/manual/en/language.types.string.php#language.types.string.syntax.heredoc

Isn't the size of character in Java 2 bytes?

The constructor String(byte[] bytes) takes the bytes from the buffer and encodes them to characters.

It uses the platform default charset to encode bytes to characters. If you know, your file contains text, that is encoded in a different charset, you can use the String(byte[] bytes, String charsetName) to use the correct encoding (from bytes to characters).

Anaconda vs. miniconda

Both Anaconda and miniconda use the conda package manager. The chief differece between between Anaconda and miniconda,however,is that

The Anaconda distribution comes pre-loaded with all the packages while the miniconda distribution is just the management system without any pre-loaded packages. If one uses miniconda, one has to download individual packages and libraries separately.

I personally use Anaconda distribution as I dont really have to worry much about individual package installations.

A disadvantage of miniconda is that installing each individual package can take a long amount of time. Compared to that installing and using Anaconda takes a lot less time.

However, there are some packages in anaconda (QtConsole, Glueviz,Orange3) that I have never had to use. I dont even know their purpose. So a disadvantage of anaconda is that it occupies more space than needed.

Simplest way to do a recursive self-join?

Check following to help the understand the concept of CTE recursion

DECLARE
@startDate DATETIME,
@endDate DATETIME

SET @startDate = '11/10/2011'
SET @endDate = '03/25/2012'

; WITH CTE AS (
    SELECT
        YEAR(@startDate) AS 'yr',
        MONTH(@startDate) AS 'mm',
        DATENAME(mm, @startDate) AS 'mon',
        DATEPART(d,@startDate) AS 'dd',
        @startDate 'new_date'
    UNION ALL
    SELECT
        YEAR(new_date) AS 'yr',
        MONTH(new_date) AS 'mm',
        DATENAME(mm, new_date) AS 'mon',
        DATEPART(d,@startDate) AS 'dd',
        DATEADD(d,1,new_date) 'new_date'
    FROM CTE
    WHERE new_date < @endDate
    )
SELECT yr AS 'Year', mon AS 'Month', count(dd) AS 'Days'
FROM CTE
GROUP BY mon, yr, mm
ORDER BY yr, mm
OPTION (MAXRECURSION 1000)

Change key pair for ec2 instance

This answer is useful in the case you no longer have SSH access to the existing server (i.e. you lost your private key).

If you still have SSH access, please use one of the answers below.

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-key-pairs.html#replacing-lost-key-pair

Here is what I did, thanks to Eric Hammond's blog post:

  1. Stop the running EC2 instance
  2. Detach its /dev/xvda1 volume (let's call it volume A) - see here
  3. Start new t1.micro EC2 instance, using my new key pair. Make sure you create it in the same subnet, otherwise you will have to terminate the instance and create it again. - see here
  4. Attach volume A to the new micro instance, as /dev/xvdf (or /dev/sdf)
  5. SSH to the new micro instance and mount volume A to /mnt/tmp
$ sudo mkdir /mnt/tmp; sudo mount /dev/xvdf1 /mnt/tmp
  1. Copy ~/.ssh/authorized_keys to /mnt/tmp/home/ubuntu/.ssh/authorized_keys
  2. Logout
  3. Terminate micro instance
  4. Detach volume A from it
  5. Attach volume A back to the main instance as /dev/xvda
  6. Start the main instance
  7. Login as before, using your new .pem file

That's it.

C# - How to add an Excel Worksheet programmatically - Office XP / 2003

Do not forget to include Reference to Microsoft Excel 12.0/11.0 object Library

using Excel = Microsoft.Office.Interop.Excel;
// Include this Namespace

Microsoft.Office.Interop.Excel.Application xlApp = null;
Excel.Workbook xlWorkbook = null;
Excel.Sheets xlSheets = null;
Excel.Worksheet xlNewSheet = null;
string worksheetName ="Sheet_Name";
object readOnly1 = false;

object isVisible = true;

object missing = System.Reflection.Missing.Value;

try
{
    xlApp = new Microsoft.Office.Interop.Excel.Application();

    if (xlApp == null)
        return;

    // Uncomment the line below if you want to see what's happening in Excel
    // xlApp.Visible = true;

    xlWorkbook = xlApp.Workbooks.Open(@"C:\Book1.xls", missing, readOnly1, missing, missing, missing, missing, missing, missing, missing, missing, isVisible, missing, missing, missing);

    xlSheets = (Excel.Sheets)xlWorkbook.Sheets;

    // The first argument below inserts the new worksheet as the first one
    xlNewSheet = (Excel.Worksheet)xlSheets.Add(xlSheets[1], Type.Missing, Type.Missing, Type.Missing);
    xlNewSheet.Name = worksheetName;

    xlWorkbook.Save();
    xlWorkbook.Close(Type.Missing, Type.Missing, Type.Missing);
    xlApp.Quit();
}
finally
{
    System.Runtime.InteropServices.Marshal.ReleaseComObject(xlNewSheet);
    System.Runtime.InteropServices.Marshal.ReleaseComObject(xlSheets);
    System.Runtime.InteropServices.Marshal.ReleaseComObject(xlWorkbook);
    System.Runtime.InteropServices.Marshal.ReleaseComObject(xlApp);
    //xlApp = null;
}

ROW_NUMBER() in MySQL

MySQL has supported the ROW_NUMBER() since version 8.0+.

If you use MySQL 8.0 or later, check it out ROW_NUMBER() function. Otherwise, you have emulate ROW_NUMBER() function.

The row_number() is a ranking function that returns a sequential number of a row, starting from 1 for the first row.

for older version,

SELECT t.*, 
       @rowid := @rowid + 1 AS ROWID
  FROM TABLE t, 
       (SELECT @rowid := 0) dummy;

How to Convert a Text File into a List in Python

Maybe:

crimefile = open(fileName, 'r')
yourResult = [line.split(',') for line in crimefile.readlines()]

Cleaning `Inf` values from an R dataframe

Also, if someone need the Infs' coordinates, can do this:

library(rlist)
list.clean(apply(df, 2, function(x){which(is.infinite(x))}), function(x) length(x) == 0L, TRUE)

Result:

$colname1
[1] row1 row2 ...
$colname2
[2] row1 row2 ... 

With this information, you can replace the Inf values in particular places with the mean, median, or whatever operator that you want.

For example (for element 01):

repInf = list.clean(apply(df, 2, function(x){which(is.infinite(x))}), function(x) length(x) == 0L, TRUE)
df[repInf[[1]], names(repInf)[[1]]] = median or mean(is.finite(df[ ,names(repInf)[[1]]]), na.rm = TRUE)

In loop:

for (nonInf in 1:length(repInf)) {
df[repInf[[nonInf]], names(repInf)[[nonInf]]] = mean(is.finite(df[ , names(repInf)[[nonInf]]]))
}

Android Center text on canvas

Try the following:

 Paint textPaint = new Paint();
 textPaint.setTextAlign(Paint.Align.CENTER);

 int xPos = (canvas.getWidth() / 2);
 int yPos = (int) ((canvas.getHeight() / 2) - ((textPaint.descent() + textPaint.ascent()) / 2)) ; 
 //((textPaint.descent() + textPaint.ascent()) / 2) is the distance from the baseline to the center.

 canvas.drawText("Hello", xPos, yPos, textPaint);

How do I invert BooleanToVisibilityConverter?

Write your own is the best solution for now. Here is an example of a Converter that can do both way Normal and Inverted. If you have any problems with this just ask.

[ValueConversion(typeof(bool), typeof(Visibility))]
public class InvertableBooleanToVisibilityConverter : IValueConverter
{
    enum Parameters
    {
        Normal, Inverted
    }

    public object Convert(object value, Type targetType,
                          object parameter, CultureInfo culture)
    {
        var boolValue = (bool)value;
        var direction = (Parameters)Enum.Parse(typeof(Parameters), (string)parameter);

        if(direction == Parameters.Inverted)
            return !boolValue? Visibility.Visible : Visibility.Collapsed;

        return boolValue? Visibility.Visible : Visibility.Collapsed;
    }

    public object ConvertBack(object value, Type targetType,
        object parameter, CultureInfo culture)
    {
        return null;
    }
}
<UserControl.Resources>
  <Converters:InvertableBooleanToVisibilityConverter x:Key="_Converter"/>
</UserControl.Resources>

<Button Visibility="{Binding IsRunning, Converter={StaticResource _Converter}, ConverterParameter=Inverted}">Start</Button>

How do I convert an ANSI encoded file to UTF-8 with Notepad++?

Regarding this part:

When I convert it to UTF-8 without bom and close file, the file is again ANSI when I reopen.

The easiest solution is to avoid the problem entirely by properly configuring Notepad++.

Try Settings -> Preferences -> New document -> Encoding -> choose UTF-8 without BOM, and check Apply to opened ANSI files.

notepad++ UTF-8 apply to opened ANSI files

That way all the opened ANSI files will be treated as UTF-8 without BOM.

For explanation what's going on, read the comments below this answer.

To fully learn about Unicode and UTF-8, read this excellent article from Joel Spolsky.

can't access mysql from command line mac

I've tried all the solutions from the answers but couldn't get mysql command to work from the terminal, always getting the message

bash: command not found

The solution is to change the .bash_profile, and add the mysql path to .bash_profile

To do so follow these steps: 1. Open a new Terminal window or make sure you are in the home directory 2. Open .bash_profile using

nano .bash_profile

3. Add the following command to add the mysql path

PATH="/usr/local/mysql/bin:${PATH}"
export PATH

4. Press Ctrl+X, then press y and press enter.

The following is how my .bash_profile looks like enter image description here

C# Threading - How to start and stop a thread

Use a static AutoResetEvent in your spawned threads to call back to the main thread using the Set() method. This guy has a fairly good demo in SO on how to use it.

AutoResetEvent clarification