Programs & Examples On #Clientbundle

An image bundle is a construct used to improve application performance by reducing the number of round trip HTTP requests to the server to fetch images.

No provider for HttpClient

I had similar problem. For me the fix was to import HttpModule before HttpClient Module:

import { HttpModule } from '@angular/http';
import { HttpClientModule } from '@angular/common/http';
.
.
.
imports: [
  BrowserModule,
  HttpModule,
  HttpClientModule
],

How to persist data in a dockerized postgres database using volumes

I think you just need to create your volume outside docker first with a docker create -v /location --name and then reuse it.

And by the time I used to use docker a lot, it wasn't possible to use a static docker volume with dockerfile definition so my suggestion is to try the command line (eventually with a script ) .

How do I check whether input string contains any spaces?

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

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

Example:

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

Convert array of JSON object strings to array of JS objects

If you have a JS array of JSON objects:

var s=['{"Select":"11","PhotoCount":"12"}','{"Select":"21","PhotoCount":"22"}'];

and you want an array of objects:

// JavaScript array of JavaScript objects
var objs = s.map(JSON.parse);

// ...or for older browsers
var objs=[];
for (var i=s.length;i--;) objs[i]=JSON.parse(s[i]);

// ...or for maximum speed:
var objs = JSON.parse('['+s.join(',')+']');

See the speed tests for browser comparisons.


If you have a single JSON string representing an array of objects:

var s='[{"Select":"11","PhotoCount":"12"},{"Select":"21","PhotoCount":"22"}]';

and you want an array of objects:

// JavaScript array of JavaScript objects
var objs = JSON.parse(s);

If you have an array of objects:

// A JavaScript array of JavaScript objects
var s = [{"Select":"11", "PhotoCount":"12"},{"Select":"21", "PhotoCount":"22"}];

…and you want JSON representation for it, then:

// JSON string representing an array of objects
var json = JSON.stringify(s);

…or if you want a JavaScript array of JSON strings, then:

// JavaScript array of strings (that are each a JSON object)
var jsons = s.map(JSON.stringify);

// ...or for older browsers
var jsons=[];
for (var i=s.length;i--;) jsons[i]=JSON.stringify(s[i]);

How to set Status Bar Style in Swift 3

  1. Chose Light Contententer image description here

  2. Add View controller-based status bar appearance with NO to .plist enter image description here

Ping a site in Python?

It's hard to say what your question is, but there are some alternatives.

If you mean to literally execute a request using the ICMP ping protocol, you can get an ICMP library and execute the ping request directly. Google "Python ICMP" to find things like this icmplib. You might want to look at scapy, also.

This will be much faster than using os.system("ping " + ip ).

If you mean to generically "ping" a box to see if it's up, you can use the echo protocol on port 7.

For echo, you use the socket library to open the IP address and port 7. You write something on that port, send a carriage return ("\r\n") and then read the reply.

If you mean to "ping" a web site to see if the site is running, you have to use the http protocol on port 80.

For or properly checking a web server, you use urllib2 to open a specific URL. (/index.html is always popular) and read the response.

There are still more potential meaning of "ping" including "traceroute" and "finger".

How to increase maximum execution time in php

use below statement if safe_mode is off

set_time_limit(0);

How to get only numeric column values?

Use This [Tested]

To get numeric

SELECT column1
FROM table
WHERE Isnumeric(column1) = 1; // will return Numeric values

To get non-numeric

SELECT column1
FROM table
WHERE Isnumeric(column1) = 0; // will return non-numeric values

How to get first N elements of a list in C#?

In case anyone is interested (even if the question does not ask for this version), in C# 2 would be: (I have edited the answer, following some suggestions)

myList.Sort(CLASS_FOR_COMPARER);
List<string> fiveElements = myList.GetRange(0, 5);

How to combine GROUP BY, ORDER BY and HAVING

ORDER BY is always last...

However, you need to pick the fields you ACTUALLY WANT then select only those and group by them. SELECT * and GROUP BY Email will give you RANDOM VALUES for all the fields but Email. Most RDBMS will not even allow you to do this because of the issues it creates, but MySQL is the exception.

SELECT Email, COUNT(*)
FROM user_log
GROUP BY Email
HAVING COUNT(*) > 1
ORDER BY UpdateDate DESC

What is the location of mysql client ".my.cnf" in XAMPP for Windows?

Apologize for resurrect this thread, but for Windows 8.x users can find my.cnf at this folder:

C:\ProgramData\MySQL\MySQL Server 5.6\my.ini

Then also can find data folder on same folder.

Android soft keyboard covers EditText field

I had the same issue and searching the people said to add adjustPan, while in my case adjustResize worked.

<activity
    android:name=".YOUR.ACTIVITY"
    ...
    android:windowSoftInputMode="adjustResize"
/>

How to check a string for a special character?

You can use string.punctuation and any function like this

import string
invalidChars = set(string.punctuation.replace("_", ""))
if any(char in invalidChars for char in word):
    print "Invalid"
else:
    print "Valid"

With this line

invalidChars = set(string.punctuation.replace("_", ""))

we are preparing a list of punctuation characters which are not allowed. As you want _ to be allowed, we are removing _ from the list and preparing new set as invalidChars. Because lookups are faster in sets.

any function will return True if atleast one of the characters is in invalidChars.

Edit: As asked in the comments, this is the regular expression solution. Regular expression taken from https://stackoverflow.com/a/336220/1903116

word = "Welcome"
import re
print "Valid" if re.match("^[a-zA-Z0-9_]*$", word) else "Invalid"

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

My problem was to display the record even if no or only one phone number exists (full address book). Therefore I used a LEFT JOIN which takes all records from the left, even if no corresponding exists on the right. For me this works in Microsoft Access SQL (they require the parenthesis!)

SELECT t.PhoneNumber1, t.PhoneNumber2, t.PhoneNumber3
   t1.SomeOtherFieldForPhone1, t2.someOtherFieldForPhone2, t3.someOtherFieldForPhone3
FROM 
(
 (
  Table1 AS t LEFT JOIN Table2 AS t3 ON t.PhoneNumber3 = t3.PhoneNumber
 )
 LEFT JOIN Table2 AS t2 ON t.PhoneNumber2 = t2.PhoneNumber
)
LEFT JOIN Table2 AS t1 ON t.PhoneNumber1 = t1.PhoneNumber;

Getting Checkbox Value in ASP.NET MVC 4

Modify Remember like this

public class MyModel
{
    public string Name { get; set; }
    public bool? Remember { get; set; }
}

Use nullable bool in controller and fallback to false on null like this

[HttpPost]
public ActionResult MyAction(MyModel model)
{
    model.Remember = model.Remember ?? false;
    Console.WriteLine(model.Remember.ToString());
}

Serializing to JSON in jQuery

The best way is to include the polyfill for JSON object.

But if you insist create a method for serializing an object to JSON notation (valid values for JSON) inside the jQuery namespace, you can do something like this:

Implementation

// This is a reference to JSON.stringify and provides a polyfill for old browsers.
// stringify serializes an object, array or primitive value and return it as JSON.
jQuery.stringify = (function ($) {
  var _PRIMITIVE, _OPEN, _CLOSE;
  if (window.JSON && typeof JSON.stringify === "function")
    return JSON.stringify;

  _PRIMITIVE = /string|number|boolean|null/;

  _OPEN = {
    object: "{",
    array: "["
  };

  _CLOSE = {
    object: "}",
    array: "]"
  };

  //actions to execute in each iteration
  function action(key, value) {
    var type = $.type(value),
      prop = "";

    //key is not an array index
    if (typeof key !== "number") {
      prop = '"' + key + '":';
    }
    if (type === "string") {
      prop += '"' + value + '"';
    } else if (_PRIMITIVE.test(type)) {
      prop += value;
    } else if (type === "array" || type === "object") {
      prop += toJson(value, type);
    } else return;
    this.push(prop);
  }

  //iterates over an object or array
  function each(obj, callback, thisArg) {
    for (var key in obj) {
      if (obj instanceof Array) key = +key;
      callback.call(thisArg, key, obj[key]);
    }
  }

  //generates the json
  function toJson(obj, type) {
    var items = [];
    each(obj, action, items);
    return _OPEN[type] + items.join(",") + _CLOSE[type];
  }

  //exported function that generates the json
  return function stringify(obj) {
    if (!arguments.length) return "";
    var type = $.type(obj);
    if (_PRIMITIVE.test(type))
      return (obj === null ? type : obj.toString());
    //obj is array or object
    return toJson(obj, type);
  }
}(jQuery));

Usage

var myObject = {
    "0": null,
    "total-items": 10,
    "undefined-prop": void(0),
    sorted: true,
    images: ["bg-menu.png", "bg-body.jpg", [1, 2]],
    position: { //nested object literal
        "x": 40,
        "y": 300,
        offset: [{ top: 23 }]
    },
    onChange: function() { return !0 },
    pattern: /^bg-.+\.(?:png|jpe?g)$/i
};

var json = jQuery.stringify(myObject);
console.log(json);

How to check if a file exists from a url

You can use the function file_get_contents();

if(file_get_contents('https://example.com/example.txt')) {
    //File exists
}

Error: The 'brew link' step did not complete successfully

You probably already installed an older version of node.js using a different method, so you need to manually remove the files that are getting in brew's way.

Do brew link -n node and manually delete those conflicting files and directories, then try brew link node again.

JOIN two SELECT statement results

you can use the UNION ALL keyword for this.

Here is the MSDN doc to do it in T-SQL http://msdn.microsoft.com/en-us/library/ms180026.aspx

UNION ALL - combines the result set

UNION- Does something like a Set Union and doesnt output duplicate values

For the difference with an example: http://sql-plsql.blogspot.in/2010/05/difference-between-union-union-all.html

Android: Rotate image in imageview by an angle

here's a nice solution for putting a rotated drawable for an imageView:

Drawable getRotateDrawable(final Bitmap b, final float angle) {
    final BitmapDrawable drawable = new BitmapDrawable(getResources(), b) {
        @Override
        public void draw(final Canvas canvas) {
            canvas.save();
            canvas.rotate(angle, b.getWidth() / 2, b.getHeight() / 2);
            super.draw(canvas);
            canvas.restore();
        }
    };
    return drawable;
}

usage:

Bitmap b=...
float angle=...
final Drawable rotatedDrawable = getRotateDrawable(b,angle);
root.setImageDrawable(rotatedDrawable);

another alternative:

private Drawable getRotateDrawable(final Drawable d, final float angle) {
    final Drawable[] arD = { d };
    return new LayerDrawable(arD) {
        @Override
        public void draw(final Canvas canvas) {
            canvas.save();
            canvas.rotate(angle, d.getBounds().width() / 2, d.getBounds().height() / 2);
            super.draw(canvas);
            canvas.restore();
        }
    };
}

also, if you wish to rotate the bitmap, but afraid of OOM, you can use an NDK solution i've made here

How to rotate portrait/landscape Android emulator?

Yes. Thanks

Ctrl + F11 for Portrait

and

Ctrl + F12 for Landscape

How can I add a hint text to WPF textbox?

You can accomplish this much more easily with a VisualBrush and some triggers in a Style:

<TextBox>
    <TextBox.Style>
        <Style TargetType="TextBox" xmlns:sys="clr-namespace:System;assembly=mscorlib">
            <Style.Resources>
                <VisualBrush x:Key="CueBannerBrush" AlignmentX="Left" AlignmentY="Center" Stretch="None">
                    <VisualBrush.Visual>
                        <Label Content="Search" Foreground="LightGray" />
                    </VisualBrush.Visual>
                </VisualBrush>
            </Style.Resources>
            <Style.Triggers>
                <Trigger Property="Text" Value="{x:Static sys:String.Empty}">
                    <Setter Property="Background" Value="{StaticResource CueBannerBrush}" />
                </Trigger>
                <Trigger Property="Text" Value="{x:Null}">
                    <Setter Property="Background" Value="{StaticResource CueBannerBrush}" />
                </Trigger>
                <Trigger Property="IsKeyboardFocused" Value="True">
                    <Setter Property="Background" Value="White" />
                </Trigger>
            </Style.Triggers>
        </Style>
    </TextBox.Style>
</TextBox>

To increase the re-usability of this Style, you can also create a set of attached properties to control the actual cue banner text, color, orientation etc.

Iterate over the lines of a string

Here are three possibilities:

foo = """
this is 
a multi-line string.
"""

def f1(foo=foo): return iter(foo.splitlines())

def f2(foo=foo):
    retval = ''
    for char in foo:
        retval += char if not char == '\n' else ''
        if char == '\n':
            yield retval
            retval = ''
    if retval:
        yield retval

def f3(foo=foo):
    prevnl = -1
    while True:
      nextnl = foo.find('\n', prevnl + 1)
      if nextnl < 0: break
      yield foo[prevnl + 1:nextnl]
      prevnl = nextnl

if __name__ == '__main__':
  for f in f1, f2, f3:
    print list(f())

Running this as the main script confirms the three functions are equivalent. With timeit (and a * 100 for foo to get substantial strings for more precise measurement):

$ python -mtimeit -s'import asp' 'list(asp.f3())'
1000 loops, best of 3: 370 usec per loop
$ python -mtimeit -s'import asp' 'list(asp.f2())'
1000 loops, best of 3: 1.36 msec per loop
$ python -mtimeit -s'import asp' 'list(asp.f1())'
10000 loops, best of 3: 61.5 usec per loop

Note we need the list() call to ensure the iterators are traversed, not just built.

IOW, the naive implementation is so much faster it isn't even funny: 6 times faster than my attempt with find calls, which in turn is 4 times faster than a lower-level approach.

Lessons to retain: measurement is always a good thing (but must be accurate); string methods like splitlines are implemented in very fast ways; putting strings together by programming at a very low level (esp. by loops of += of very small pieces) can be quite slow.

Edit: added @Jacob's proposal, slightly modified to give the same results as the others (trailing blanks on a line are kept), i.e.:

from cStringIO import StringIO

def f4(foo=foo):
    stri = StringIO(foo)
    while True:
        nl = stri.readline()
        if nl != '':
            yield nl.strip('\n')
        else:
            raise StopIteration

Measuring gives:

$ python -mtimeit -s'import asp' 'list(asp.f4())'
1000 loops, best of 3: 406 usec per loop

not quite as good as the .find based approach -- still, worth keeping in mind because it might be less prone to small off-by-one bugs (any loop where you see occurrences of +1 and -1, like my f3 above, should automatically trigger off-by-one suspicions -- and so should many loops which lack such tweaks and should have them -- though I believe my code is also right since I was able to check its output with other functions').

But the split-based approach still rules.

An aside: possibly better style for f4 would be:

from cStringIO import StringIO

def f4(foo=foo):
    stri = StringIO(foo)
    while True:
        nl = stri.readline()
        if nl == '': break
        yield nl.strip('\n')

at least, it's a bit less verbose. The need to strip trailing \ns unfortunately prohibits the clearer and faster replacement of the while loop with return iter(stri) (the iter part whereof is redundant in modern versions of Python, I believe since 2.3 or 2.4, but it's also innocuous). Maybe worth trying, also:

    return itertools.imap(lambda s: s.strip('\n'), stri)

or variations thereof -- but I'm stopping here since it's pretty much a theoretical exercise wrt the strip based, simplest and fastest, one.

Can Android do peer-to-peer ad-hoc networking?

It might work to use JmDNS on Android: http://jmdns.sourceforge.net/

There are tons of zeroconf-enabled machines out there, so this would enable discovery with more than just Android devices.

Stored procedure - return identity as output parameter or scalar

Its all depend on your client data access-layer. Many ORM frameworks rely on explicitly querying the SCOPE_IDENTITY during the insert operation.

If you are in complete control over the data access layer then is arguably better to return SCOPE_IDENTITY() as an output parameter. Wrapping the return in a result set adds unnecessary meta data overhead to describe the result set, and complicates the code to process the requests result.

If you prefer a result set return, then again is arguable better to use the OUTPUT clause:

INSERT INTO  MyTable (col1, col2, col3)
OUTPUT INSERTED.id, col1, col2, col3
VALUES (@col1, @col2, @col3);

This way you can get the entire inserted row back, including default and computed columns, and you get a result set containing one row for each row inserted, this working correctly with set oriented batch inserts.

Overall, I can't see a single case when returning SCOPE_IDENTITY() as a result set would be a good practice.

How to avoid HTTP error 429 (Too Many Requests) python

In many cases, continuing to scrape data from a website even when the server is requesting you not to is unethical. However, in the cases where it isn't, you can utilize a list of public proxies in order to scrape a website with many different IP addresses.

How to call a Python function from Node.js

Easiest way I know of is to use "child_process" package which comes packaged with node.

Then you can do something like:

const spawn = require("child_process").spawn;
const pythonProcess = spawn('python',["path/to/script.py", arg1, arg2, ...]);

Then all you have to do is make sure that you import sys in your python script, and then you can access arg1 using sys.argv[1], arg2 using sys.argv[2], and so on.

To send data back to node just do the following in the python script:

print(dataToSendBack)
sys.stdout.flush()

And then node can listen for data using:

pythonProcess.stdout.on('data', (data) => {
    // Do something with the data returned from python script
});

Since this allows multiple arguments to be passed to a script using spawn, you can restructure a python script so that one of the arguments decides which function to call, and the other argument gets passed to that function, etc.

Hope this was clear. Let me know if something needs clarification.

SQL command to display history of queries

For MySQL > 5.1.11 or MariaDB

  1. SET GLOBAL log_output = 'TABLE';
  2. SET GLOBAL general_log = 'ON';
  3. Take a look at the table mysql.general_log

If you want to output to a log file:

  1. SET GLOBAL log_output = "FILE";
  2. SET GLOBAL general_log_file = "/path/to/your/logfile.log"
  3. SET GLOBAL general_log = 'ON';

As mentioned by jeffmjack in comments, these settings will be forgetting before next session unless you edit the configuration files (e.g. edit /etc/mysql/my.cnf, then restart to apply changes).

Now, if you'd like you can tail -f /var/log/mysql/mysql.log

More info here: Server System Variables

std::cin input with spaces?

THE C WAY

You can use gets function found in cstdio(stdio.h in c):

#include<cstdio>
int main(){

char name[256];
gets(name); // for input
puts(name);// for printing 
}

THE C++ WAY

gets is removed in c++11.

[Recommended]:You can use getline(cin,name) which is in string.h or cin.getline(name,256) which is in iostream itself.

#include<iostream>
#include<string>
using namespace std;
int main(){

char name1[256];
string name2;
cin.getline(name1,256); // for input
getline(cin,name2); // for input
cout<<name1<<"\n"<<name2;// for printing
}

Singletons vs. Application Context in Android?

I very much disagree with Dianne Hackborn's response. We are bit by bit removing all singletons from our project in favor of lightweight, task scoped objects which can easiliy be re-created when you actually need them.

Singletons are a nightmare for testing and, if lazily initialized, will introduce "state indeterminism" with subtle side effects (which may suddenly surface when moving calls to getInstance() from one scope to another). Visibility has been mentioned as another problem, and since singletons imply "global" (= random) access to shared state, subtle bugs may arise when not properly synchronized in concurrent applications.

I consider it an anti-pattern, it's a bad object-oriented style that essentially amounts to maintaining global state.

To come back to your question:

Although the app context can be considered a singleton itself, it is framework-managed and has a well defined life-cycle, scope, and access path. Hence I believe that if you do need to manage app-global state, it should go here, nowhere else. For anything else, rethink if you really need a singleton object, or if it would also be possible to rewrite your singleton class to instead instantiate small, short-lived objects that perform the task at hand.

Regular expression for number with length of 4, 5 or 6

Try this:

^[0-9]{4,6}$

{4,6} = between 4 and 6 characters, inclusive.

Have a variable in images path in Sass?

No need for a function:

$assetPath : "/assets/images";

...

body {
  margin: 0 auto;
  background: url(#{$assetPath}/site/background.jpg) repeat-x fixed 0 0;
  width: 100%; }

See the interpolation docs for details.

How to get instance variables in Python?

Suggest

>>> print vars.__doc__
vars([object]) -> dictionary

Without arguments, equivalent to locals().
With an argument, equivalent to object.__dict__.

In otherwords, it essentially just wraps __dict__

RecyclerView vs. ListView

Advantages of RecyclerView over listview :

  1. Contains ViewHolder by default.

  2. Easy animations.

  3. Supports horizontal , grid and staggered layouts

Advantages of listView over recyclerView :

  1. Easy to add divider.

  2. Can use inbuilt arrayAdapter for simple plain lists

  3. Supports Header and footer .

  4. Supports OnItemClickListner .

CSS rounded corners in IE8

PIE.htc worked for me great (http://css3pie.com/), but with one issue:

You should write absolute path to PIE.htc. It hasn't worked for me when I used relative path.

How do I turn off PHP Notices?

You can set display_errors to 0 or use the error_reporting() function.

However, notices are annoying (I can partly sympathize) but they serve a purpose. You shouldn't be defining a constant twice, the second time won't work and the constant will remain unchanged!

AngularJS - Value attribute on an input text box is ignored when there is a ng-model used?

This is a slight modification to the earlier answers...

There is no need for $parse

angular.directive('input', [function () {
  'use strict';

  var directiveDefinitionObject = {
    restrict: 'E',
    require: '?ngModel',
    link: function postLink(scope, iElement, iAttrs, ngModelController) {
      if (iAttrs.value && ngModelController) {
        ngModelController.$setViewValue(iAttrs.value);
      }
    }
  };

  return directiveDefinitionObject;
}]);

How can I do a line break (line continuation) in Python?

Taken from The Hitchhiker's Guide to Python (Line Continuation):

When a logical line of code is longer than the accepted limit, you need to split it over multiple physical lines. The Python interpreter will join consecutive lines if the last character of the line is a backslash. This is helpful in some cases, but should usually be avoided because of its fragility: a white space added to the end of the line, after the backslash, will break the code and may have unexpected results.

A better solution is to use parentheses around your elements. Left with an unclosed parenthesis on an end-of-line the Python interpreter will join the next line until the parentheses are closed. The same behaviour holds for curly and square braces.

However, more often than not, having to split a long logical line is a sign that you are trying to do too many things at the same time, which may hinder readability.

Having that said, here's an example considering multiple imports (when exceeding line limits, defined on PEP-8), also applied to strings in general:

from app import (
    app, abort, make_response, redirect, render_template, request, session
)

Should I use Java's String.format() if performance is important?

I wrote a small class to test which has the better performance of the two and + comes ahead of format. by a factor of 5 to 6. Try it your self

import java.io.*;
import java.util.Date;

public class StringTest{

    public static void main( String[] args ){
    int i = 0;
    long prev_time = System.currentTimeMillis();
    long time;

    for( i = 0; i< 100000; i++){
        String s = "Blah" + i + "Blah";
    }
    time = System.currentTimeMillis() - prev_time;

    System.out.println("Time after for loop " + time);

    prev_time = System.currentTimeMillis();
    for( i = 0; i<100000; i++){
        String s = String.format("Blah %d Blah", i);
    }
    time = System.currentTimeMillis() - prev_time;
    System.out.println("Time after for loop " + time);

    }
}

Running the above for different N shows that both behave linearly, but String.format is 5-30 times slower.

The reason is that in the current implementation String.format first parses the input with regular expressions and then fills in the parameters. Concatenation with plus, on the other hand, gets optimized by javac (not by the JIT) and uses StringBuilder.append directly.

Runtime comparison

ToggleClass animate jQuery?

jQuery UI extends the jQuery native toggleClass to take a second optional parameter: duration

toggleClass( class, [duration] )

Docs + DEMO

Is there a way to make text unselectable on an HTML page?

In most browsers, this can be achieved using CSS:

*.unselectable {
   -moz-user-select: -moz-none;
   -khtml-user-select: none;
   -webkit-user-select: none;

   /*
     Introduced in IE 10.
     See http://ie.microsoft.com/testdrive/HTML5/msUserSelect/
   */
   -ms-user-select: none;
   user-select: none;
}

For IE < 10 and Opera, you will need to use the unselectable attribute of the element you wish to be unselectable. You can set this using an attribute in HTML:

<div id="foo" unselectable="on" class="unselectable">...</div>

Sadly this property isn't inherited, meaning you have to put an attribute in the start tag of every element inside the <div>. If this is a problem, you could instead use JavaScript to do this recursively for an element's descendants:

function makeUnselectable(node) {
    if (node.nodeType == 1) {
        node.setAttribute("unselectable", "on");
    }
    var child = node.firstChild;
    while (child) {
        makeUnselectable(child);
        child = child.nextSibling;
    }
}

makeUnselectable(document.getElementById("foo"));

How do I clear the std::queue efficiently?

Assuming your m_Queue contains integers:

std::queue<int>().swap(m_Queue)

Otherwise, if it contains e.g. pointers to Job objects, then:

std::queue<Job*>().swap(m_Queue)

This way you swap an empty queue with your m_Queue, thus m_Queue becomes empty.

Pros/cons of using redux-saga with ES6 generators vs redux-thunk with ES2017 async/await

I will add my experience using saga in production system in addition to the library author's rather thorough answer.

Pro (using saga):

  • Testability. It's very easy to test sagas as call() returns a pure object. Testing thunks normally requires you to include a mockStore inside your test.

  • redux-saga comes with lots of useful helper functions about tasks. It seems to me that the concept of saga is to create some kind of background worker/thread for your app, which act as a missing piece in react redux architecture(actionCreators and reducers must be pure functions.) Which leads to next point.

  • Sagas offer independent place to handle all side effects. It is usually easier to modify and manage than thunk actions in my experience.

Con:

  • Generator syntax.

  • Lots of concepts to learn.

  • API stability. It seems redux-saga is still adding features (eg Channels?) and the community is not as big. There is a concern if the library makes a non backward compatible update some day.

Session 'app': Error Installing APK

I tried invalidating cache, deleting build folder and gradle sync. Also, I couldn't uninstall because the app is not visible on device. So I tried uninstalling through ADB and it worked.

adb uninstall <package_name>

Differences between utf8 and latin1

In latin1 each character is exactly one byte long. In utf8 a character can consist of more than one byte. Consequently utf8 has more characters than latin1 (and the characters they do have in common aren't necessarily represented by the same byte/bytesequence).

How to change the display name for LabelFor in razor in mvc3?

@Html.LabelFor(model => model.SomekingStatus, "foo bar")

Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured

In my case

spring.profiles = production // remove it to fix

in application.properties was the reason

Set up git to pull and push all branches

Including the + in the push spec is probably a bad idea, as it means that git will happily do a non-fast-forward push even without -f, and if the remote server is set up to accept those, you can lose history.

Try just this:

$ git config --add remote.origin.push 'refs/heads/*:refs/heads/*'
$ git config --add remote.origin.push 'refs/tags/*:refs/tags/*'
$ git config --add remote.origin.fetch 'refs/heads/*:refs/remotes/origin/*'
$ git config --add remote.origin.fetch 'refs/tags/*:refs/tags/*'

How do I import global modules in Node? I get "Error: Cannot find module <module>"?

Setting the environment variable NODE_PATH to point to your global node_modules folder.

In Windows 7 or higher the path is something like %AppData%\npm\node_modules while in UNIX could be something like /home/sg/.npm_global/lib/node_modules/ but it depends on user configuration.

The command npm config get prefix could help finding out which is the correct path.

In UNIX systems you can accomplish it with the following command:

export NODE_PATH=`npm config get prefix`/lib/node_modules/

MIN and MAX in C

The maximum of two integers a and b is (int)(0.5((a+b)+abs(a-b))). This may also work with (double) and fabs(a-b) for doubles (similar for floats)

Using jQuery, Restricting File Size Before Uploading

I found that Apache2 (you might want to also check Apache 1.5) has a way to restrict this before uploading by dropping this in your .htaccess file:

LimitRequestBody 2097152

This restricts it to 2 megabytes (2 * 1024 * 1024) on file upload (if I did my byte math properly).

Note when you do this, the Apache error log will generate this entry when you exceed this limit on a form post or get request:

Requested content-length of 4000107 is larger than the configured limit of 2097152

And it will also display this message back in the web browser:

<h1>Request Entity Too Large</h1>

So, if you're doing AJAX form posts with something like the Malsup jQuery Form Plugin, you could trap for the H1 response like this and show an error result.

By the way, the error number returned is 413. So, you could use a directive in your .htaccess file like...

Redirect 413 413.html

...and provide a more graceful error result back.

LNK2019: unresolved external symbol _main referenced in function ___tmainCRTStartup

I had this happen in Visual Studio 2015 too for an interesting reason. Just adding it here in case it happens to someone else.

I already had number of files in project and I was adding another one that would have main function in it, however when I initially added the file I made a typo in the extension (.coo instead of .cpp). I corrected that but when I was done I got this error. It turned out that Visual Studio was being smart and when file was added it decided that it is not a source file due to the initial extension.

Right-clicking on file in solution explorer and selecting Properties -> General -> ItemType and setting it to "C/C++ compiler" fixed the issue.

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: No operations allowed after connection closed

  1. First Replace the MySQL dependency as given below

    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.44</version>
    </dependency>
    
  2. An error showing "Authentication plugin 'caching_sha2_password'" will appear. Run this command:

    mysql -u root -p
    ALTER USER 'username'@'localhost' IDENTIFIED WITH mysql_native_password BY 'password';
    

python pandas: apply a function with arguments to a series

Series.apply(func, convert_dtype=True, args=(), **kwds)

args : tuple

x = my_series.apply(my_function, args = (arg1,))

How to redraw DataTable with new data

Another alternative is

dtColumns[index].visible = false/true;

To show or hide any column.

Why use def main()?

"What does if __name__==“__main__”: do?" has already been answered.

Having a main() function allows you to call its functionality if you import the module. The main (no pun intended) benefit of this (IMHO) is that you can unit test it.

Map HTML to JSON

Representing complex HTML documents will be difficult and full of corner cases, but I just wanted to share a couple techniques to show how to get this kind of program started. This answer differs in that it uses data abstraction and the toJSON method to recursively build the result

Below, html2json is a tiny function which takes an HTML node as input and it returns a JSON string as the result. Pay particular attention to how the code is quite flat but it's still plenty capable of building a deeply nested tree structure – all possible with virtually zero complexity

_x000D_
_x000D_
// data Elem = Elem Node_x000D_
_x000D_
const Elem = e => ({_x000D_
  toJSON : () => ({_x000D_
    tagName: _x000D_
      e.tagName,_x000D_
    textContent:_x000D_
      e.textContent,_x000D_
    attributes:_x000D_
      Array.from(e.attributes, ({name, value}) => [name, value]),_x000D_
    children:_x000D_
      Array.from(e.children, Elem)_x000D_
  })_x000D_
})_x000D_
_x000D_
// html2json :: Node -> JSONString_x000D_
const html2json = e =>_x000D_
  JSON.stringify(Elem(e), null, '  ')_x000D_
  _x000D_
console.log(html2json(document.querySelector('main')))
_x000D_
<main>_x000D_
  <h1 class="mainHeading">Some heading</h1>_x000D_
  <ul id="menu">_x000D_
    <li><a href="/a">a</a></li>_x000D_
    <li><a href="/b">b</a></li>_x000D_
    <li><a href="/c">c</a></li>_x000D_
  </ul>_x000D_
  <p>some text</p>_x000D_
</main>
_x000D_
_x000D_
_x000D_

In the previous example, the textContent gets a little butchered. To remedy this, we introduce another data constructor, TextElem. We'll have to map over the childNodes (instead of children) and choose to return the correct data type based on e.nodeType – this gets us a littler closer to what we might need

_x000D_
_x000D_
// data Elem = Elem Node | TextElem Node_x000D_
_x000D_
const TextElem = e => ({_x000D_
  toJSON: () => ({_x000D_
    type:_x000D_
      'TextElem',_x000D_
    textContent:_x000D_
      e.textContent_x000D_
  })_x000D_
})_x000D_
_x000D_
const Elem = e => ({_x000D_
  toJSON : () => ({_x000D_
    type:_x000D_
      'Elem',_x000D_
    tagName: _x000D_
      e.tagName,_x000D_
    attributes:_x000D_
      Array.from(e.attributes, ({name, value}) => [name, value]),_x000D_
    children:_x000D_
      Array.from(e.childNodes, fromNode)_x000D_
  })_x000D_
})_x000D_
_x000D_
// fromNode :: Node -> Elem_x000D_
const fromNode = e => {_x000D_
  switch (e.nodeType) {_x000D_
    case 3:  return TextElem(e)_x000D_
    default: return Elem(e)_x000D_
  }_x000D_
}_x000D_
_x000D_
// html2json :: Node -> JSONString_x000D_
const html2json = e =>_x000D_
  JSON.stringify(Elem(e), null, '  ')_x000D_
  _x000D_
console.log(html2json(document.querySelector('main')))
_x000D_
<main>_x000D_
  <h1 class="mainHeading">Some heading</h1>_x000D_
  <ul id="menu">_x000D_
    <li><a href="/a">a</a></li>_x000D_
    <li><a href="/b">b</a></li>_x000D_
    <li><a href="/c">c</a></li>_x000D_
  </ul>_x000D_
  <p>some text</p>_x000D_
</main>
_x000D_
_x000D_
_x000D_

Anyway, that's just two iterations on the problem. Of course you'll have to address corner cases where they come up, but what's nice about this approach is that it gives you a lot of flexibility to encode the HTML however you wish in JSON – and without introducing too much complexity

In my experience, you could keep iterating with this technique and achieve really good results. If this answer is interesting to anyone and would like me to expand upon anything, let me know ^_^

Related: Recursive methods using JavaScript: building your own version of JSON.stringify

CSS fixed width in a span

Unfortunately inline elements (or elements having display:inline) ignore the width property. You should use floating divs instead:

<style type="text/css">
div.f1 { float: left; width: 20px; }
div.f2 { float: left; }
div.f3 { clear: both; }
</style>

<div class="f1"></div><div class="f2">The Lazy dog</div><div class="f3"></div>
<div class="f1">AND</div><div class="f2">The Lazy cat</div><div class="f3"></div>
<div class="f1">OR</div><div class="f2">The active goldfish</div><div class="f3"></div>

Now I see you need to use spans and lists, so we need to rewrite this a little bit:

<html><head>
<style type="text/css">
        span.f1 { display: block; float: left; clear: left; width: 60px; }
    li { list-style-type: none; }
    </style>

</head><body>
<ul>
<li><span class="f1">&nbsp;</span>The lazy dog.</li>
<li><span class="f1">AND</span> The lazy cat.</li>
<li><span class="f1">OR</span> The active goldfish.</li>
</ul>
</body>
</html>

How to get href value using jQuery?

It works... Tested in IE8 (don't forget to allow javascript to run if you're testing the file from your computer) and chrome.

Difference between & and && in Java?

& is bitwise. && is logical.

& evaluates both sides of the operation.
&& evaluates the left side of the operation, if it's true, it continues and evaluates the right side.

How to recursively find and list the latest modified files in a directory with subdirectories and times

Ignoring hidden files — with nice & fast time stamp

Handles spaces in filenames well — not that you should use those!

$ find . -type f -not -path '*/\.*' -printf '%TY.%Tm.%Td %THh%TM %Ta %p\n' |sort -nr |head -n 10

2017.01.28 07h00 Sat ./recent
2017.01.21 10h49 Sat ./hgb
2017.01.16 07h44 Mon ./swx
2017.01.10 18h24 Tue ./update-stations
2017.01.09 10h38 Mon ./stations.json

More find galore can be found by following the link.

Converting a string to int in Groovy

As an addendum to Don's answer, not only does groovy add a .toInteger() method to Strings, it also adds toBigDecimal(), toBigInteger(), toBoolean(), toCharacter(), toDouble(), toFloat(), toList(), and toLong().

In the same vein, groovy also adds is* eqivalents to all of those that return true if the String in question can be parsed into the format in question.

The relevant GDK page is here.

How to correctly assign a new string value?

The two structs are different. When you initialize the first struct, about 40 bytes of memory are allocated. When you initialize the second struct, about 10 bytesof memory are allocated. (Actual amount is architecture dependent)

You can use the string literals (string constants) to initalize character arrays. This is why

person p = {"John", "Doe",30};

works in the first example.

You cannot assign (in the conventional sense) a string in C.

The string literals you have ("John") are loaded into memory when your code executes. When you initialize an array with one of these literals, then the string is copied into a new memory location. In your second example, you are merely copying the pointer to (location of) the string literal. Doing something like:

char* string = "Hello";
*string = 'C'

might cause compile or runtime errors (I am not sure.) It is a bad idea because you are modifying the literal string "Hello" which, for example on a microcontroler, could be located in read-only memory.

How do I escape special characters in MySQL?

For testing how to insert the double quotes in MySQL using the terminal, you can use the following way:

TableName(Name,DString) - > Schema
insert into TableName values("Name","My QQDoubleQuotedStringQQ")

After inserting the value you can update the value in the database with double quotes or single quotes:

update table TableName replace(Dstring, "QQ", "\"")

How to call a stored procedure (with parameters) from another stored procedure without temp table

You can just call the Execute command.

EXEC spDoSomthing @myDate

Edit:

Since you want to return data..that's a little harder. You can use user defined functions instead that return data.

How do I convert datetime to ISO 8601 in PHP

You can try this way:

$datetime = new DateTime('2010-12-30 23:21:46');

echo $datetime->format(DATE_ATOM);

Dialogs / AlertDialogs: How to "block execution" while dialog is up (.NET-style)

just to answer your question...btw sry that i'm 9 months late:D...there's a "workaround" 4 this kind of problems. i.e.

new AlertDialog.Builder(some_class.this).setTitle("bla").setMessage("bla bla").show();
wait();

simply add wait();

and them in the OnClickListener start the class again with notify() something like this

@Override
    public void onClick(DialogInterface dialog, int item) {
        Toast.makeText(getApplicationContext(), "test", Toast.LENGTH_LONG).show();
        **notify**();
        dialog.cancel();
    }

the same workaround goes 4 toasts and other async calls in android

Change New Google Recaptcha (v2) Width

It's been late, but just want to help others if still facing an issue. I found nice JS solution here : https://github.com/google/recaptcha/issues/61#issuecomment-376484690


Here is JavaScript code using jQuery to do so:

$(document).ready(function () {        
    var width = $('.g-recaptcha').parent().width();
    if (width < 302) {
        var scale = width / 302;
        $('.g-recaptcha').css('transform', 'scale(' + scale + ')');
        $('.g-recaptcha').css('-webkit-transform', 'scale(' + scale + ')');
        $('.g-recaptcha').css('transform-origin', '0 0');
        $('.g-recaptcha').css('-webkit-transform-origin', '0 0');
    }
}); 

IMP Note : It will support All Devices, above and bellow 320px width as well.

How to ignore ansible SSH authenticity checking?

forward to nikobelia

For those who using jenkins to run the play book, I just added to my jenkins job before running the ansible-playbook the he environment variable ANSIBLE_HOST_KEY_CHECKING = False For instance this:

export ANSIBLE_HOST_KEY_CHECKING=False
ansible-playbook 'playbook.yml' \
--extra-vars="some vars..." \
--tags="tags_name..." -vv

How to use an array list in Java?

If you use Java 1.5 or beyond you could use:

List<String> S = new ArrayList<String>();
s.add("My text");

for (String item : S) {
  System.out.println(item);
}

Convert columns to string in Pandas

If you need to convert ALL columns to strings, you can simply use:

df = df.astype(str)

This is useful if you need everything except a few columns to be strings/objects, then go back and convert the other ones to whatever you need (integer in this case):

 df[["D", "E"]] = df[["D", "E"]].astype(int) 

Checking whether a string starts with XXXX

RanRag has already answered it for your specific question.

However, more generally, what you are doing with

if [[ "$string" =~ ^hello ]]

is a regex match. To do the same in Python, you would do:

import re
if re.match(r'^hello', somestring):
    # do stuff

Obviously, in this case, somestring.startswith('hello') is better.

Calculating difference between two timestamps in Oracle in milliseconds

I know that many people finding this solution simple and clear:

create table diff_timestamp (
f1 timestamp
, f2 timestamp);

insert into diff_timestamp values(systimestamp-1, systimestamp+2);
commit;

select cast(f2 as date) - cast(f1 as date) from diff_timestamp;

bingo!

Getting 404 Not Found error while trying to use ErrorDocument

The ErrorDocument directive, when supplied a local URL path, expects the path to be fully qualified from the DocumentRoot. In your case, this means that the actual path to the ErrorDocument is

ErrorDocument 404 /hellothere/error/404page.html

CSS: how do I create a gap between rows in a table?

If you stick with the design using tables the best idea will be to give an empty row with no content and specified height between each rows in the table.

You can use div to avoid this complexity. Just give a margin to each div.

Forcing a postback

A postback is triggered after a form submission, so it's related to a client action... take a look here for an explanation: ASP.NET - Is it possible to trigger a postback from server code?

and here for a solution: http://forums.asp.net/t/928411.aspx/1

Entity Framework and SQL Server View

If you do not want to mess with what should be the primary key, I recommend:

  1. Incorporate ROW_NUMBER into your selection
  2. Set it as primary key
  3. Set all other columns/members as non-primary in the model

Conda command not found

If you're using zsh and it has not been set up to read .bashrc, you need to add the Miniconda directory to the zsh shell PATH environment variable. Add this to your .zshrc:

export PATH="/home/username/miniconda/bin:$PATH"

Make sure to replace /home/username/miniconda with your actual path.

Save, exit the terminal and then reopen the terminal. conda command should work.

Removing whitespace from strings in Java

\W means "non word character". The pattern for whitespace characters is \s. This is well documented in the Pattern javadoc.

how to rotate a bitmap 90 degrees

I would simplify comm1x's Kotlin extension function even more:

fun Bitmap.rotate(degrees: Float) =
    Bitmap.createBitmap(this, 0, 0, width, height, Matrix().apply { postRotate(degrees) }, true)

JSON Invalid UTF-8 middle byte

On the off chance it may help others I'll share a related anecdote.

I encountered this exact error (Invalid UTF-8 middle byte 0x3f) running a PowerShell script via the PowerShell Integrated Script Environment (ISE). The identical script, executed outside the ISE, works fine. The code uses the Confluence v3 and v5.x REST APIs and this error is logged on the Confluence v5.x server - presumably because the ISE somehow mucks with the request.

Convert an int to ASCII character

Doing college work I gathered the data I found and gave me this result:

"The input consists of a single line with multiple integers, separated by a blank space. The end of the entry is identified by the number -1, which should not be processed."

#include <iostream>
#include <cstdlib>

using namespace std;

int main()
{
    char numeros[100]; //vetor para armazenar a entrada dos numeros a serem convertidos
    int count = 0, soma = 0;

    cin.getline(numeros, 100);

    system("cls"); // limpa a tela

    for(int i = 0; i < 100; i++)
    {
        if (numeros[i] == '-') // condicao de existencia do for
            i = 100;
        else
        {
            if(numeros[i] == ' ') // condicao que ao encontrar um espaco manda o resultado dos dados lidos e zera a contagem
            {
                if(count == 2) // se contegem for 2 divide por 10 por nao ter casa da centena
                    soma = soma / 10;
                if(count == 1) // se contagem for 1 divide por 100 por nao ter casa da dezena
                    soma = soma / 100;


                cout << (char)soma; // saida das letras do codigo ascii
                count = 0;

            }
            else
            {
                count ++; // contagem aumenta para saber se o numero esta na centena/dezena ou unitaria
                if(count == 1)
                    soma =  ('0' - numeros[i]) * -100; // a ideia é que o resultado de '0' - 'x' = -x (um numero inteiro)
                if(count == 2)
                    soma = soma + ('0' - numeros[i]) * -10; // todos multiplicam por -1 para retornar um valor positivo
                if(count == 3)
                    soma = soma + ('0' - numeros[i]) * -1; /* caso pense em entrada de valores na casa do milhar, deve-se alterar esses 3 if´s
        alem de adicionar mais um para a casa do milhar. */
            }
        }
    }

    return 0;
}

The comments are in Portuguese but I think you should understand. Any questions send me a message on linkedin: https://www.linkedin.com/in/marcosfreitasds/

brew install mysql on macOS

Homebrew

  1. First, make sure you have homebrew installed
  2. Run brew doctor and address anything homebrew wants you to fix
  3. Run brew install mysql
  4. Run brew services restart mysql
  5. Run mysql.server start
  6. Run mysql_secure_installation

How to rollback everything to previous commit

If you have pushed the commits upstream...

Select the commit you would like to roll back to and reverse the changes by clicking Reverse File, Reverse Hunk or Reverse Selected Lines. Do this for all the commits after the commit you would like to roll back to also.

reverse stuff reverse commit

If you have not pushed the commits upstream...

Right click on the commit and click on Reset current branch to this commit.

reset branch to commit

View markdown files offline

Check out Haroopad. This is a really nice #markdown editor. It is free and available for multiple platforms. I've tried it on Mac OSX.

Hide header in stack navigator React navigation

UPDATE as of version 5

As of version 5 it is the option headerShown in screenOptions

Example of usage:

<Stack.Navigator
  screenOptions={{
    headerShown: false
  }}
>
  <Stack.Screen name="route-name" component={ScreenComponent} />
</Stack.Navigator>

If you want only to hide the header on 1 screen you can do this by setting the screenOptions on the screen component see below for example:

<Stack.Screen options={{headerShown: false}} name="route-name" component={ScreenComponent} />

See also the blog about version 5

UPDATE
As of version 2.0.0-alpha.36 (2019-11-07),
there is a new navigationOption: headershown

      navigationOptions: {
        headerShown: false,
      }

https://reactnavigation.org/docs/stack-navigator#headershown

https://github.com/react-navigation/react-navigation/commit/ba6b6ae025de2d586229fa8b09b9dd5732af94bd

Old answer

I use this to hide the stack bar (notice this is the value of the second param):

{
    headerMode: 'none',
    navigationOptions: {
        headerVisible: false,
    }
}

When you use the this method it will be hidden on all screens.

In your case it will look like this:

const MainNavigation = StackNavigator({
  otp: { screen: OTPlogin },
  otpverify: { screen: OTPverification },
  userVerified: {
    screen: TabNavigator({
    List: { screen: List },
    Settings: { screen: Settings }
   }),
 }
},
{
  headerMode: 'none',
  navigationOptions: {
    headerVisible: false,
  }
 }
);

How to find most common elements of a list?

To just return a list containing the most common words:

from collections import Counter
words=["i", "love", "you", "i", "you", "a", "are", "you", "you", "fine", "green"]
most_common_words= [word for word, word_count in Counter(words).most_common(3)]
print most_common_words

this prints:

['you', 'i', 'a']

the 3 in "most_common(3)", specifies the number of items to print. Counter(words).most_common() returns a a list of tuples with each tuple having the word as the first member and the frequency as the second member.The tuples are ordered by the frequency of the word.

`most_common = [item for item in Counter(words).most_common()]
print(str(most_common))
[('you', 4), ('i', 2), ('a', 1), ('are', 1), ('green', 1), ('love',1), ('fine', 1)]`

"the word for word, word_counter in", extracts only the first member of the tuple.

Can I set the height of a div based on a percentage-based width?

This can be done with a CSS hack (see the other answers), but it can also be done very easily with JavaScript.

Set the div's width to (for example) 50%, use JavaScript to check its width, and then set the height accordingly. Here's a code example using jQuery:

_x000D_
_x000D_
$(function() {_x000D_
    var div = $('#dynamicheight');_x000D_
    var width = div.width();_x000D_
    _x000D_
    div.css('height', width);_x000D_
});
_x000D_
#dynamicheight_x000D_
{_x000D_
    width: 50%;_x000D_
    _x000D_
    /* Just for looks: */_x000D_
    background-color: cornflowerblue;_x000D_
    margin: 25px;_x000D_
}
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>_x000D_
_x000D_
<div id="dynamicheight"></div>
_x000D_
_x000D_
_x000D_

If you want the box to scale with the browser window on resize, move the code to a function and call it on the window resize event. Here's a demonstration of that too (view example full screen and resize browser window):

_x000D_
_x000D_
$(window).ready(updateHeight);_x000D_
$(window).resize(updateHeight);_x000D_
_x000D_
function updateHeight()_x000D_
{_x000D_
    var div = $('#dynamicheight');_x000D_
    var width = div.width();_x000D_
    _x000D_
    div.css('height', width);_x000D_
}
_x000D_
#dynamicheight_x000D_
{_x000D_
    width: 50%;_x000D_
    _x000D_
    /* Just for looks: */_x000D_
    background-color: cornflowerblue;_x000D_
    margin: 25px;_x000D_
}
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>_x000D_
_x000D_
<div id="dynamicheight"></div>
_x000D_
_x000D_
_x000D_

git: How to ignore all present untracked files?

-u no doesn't show unstaged files either. -uno works as desired and shows unstaged, but hides untracked.

How to resolve git's "not something we can merge" error

This error suggest that the branch from where you want to merge changes (i.e. in you case branch-name) is not present in you local, so you should checkout the branch and fetch the local changes. Checkout to your master branch and fetch, then follow the below steps:

git checkout branch-name
git pull
git checkout new-branch-name
git merge branch-name

Multiple linear regression in Python

Scikit-learn is a machine learning library for Python which can do this job for you. Just import sklearn.linear_model module into your script.

Find the code template for Multiple Linear Regression using sklearn in Python:

import numpy as np
import matplotlib.pyplot as plt #to plot visualizations
import pandas as pd

# Importing the dataset
df = pd.read_csv(<Your-dataset-path>)
# Assigning feature and target variables
X = df.iloc[:,:-1]
y = df.iloc[:,-1]

# Use label encoders, if you have any categorical variable
from sklearn.preprocessing import LabelEncoder
labelencoder = LabelEncoder()
X['<column-name>'] = labelencoder.fit_transform(X['<column-name>'])

from sklearn.preprocessing import OneHotEncoder
onehotencoder = OneHotEncoder(categorical_features = ['<index-value>'])
X = onehotencoder.fit_transform(X).toarray()

# Avoiding the dummy variable trap
X = X[:,1:] # Usually done by the algorithm itself

#Spliting the data into test and train set
from sklearn.model_selection import train_test_split
X_train, X_test, y_train, y_test = train_test_split(X,y, random_state = 0, test_size = 0.2)

# Fitting the model
from sklearn.linear_model import LinearRegression
regressor = LinearRegression()
regressor.fit(X_train, y_train)

# Predicting the test set results
y_pred = regressor.predict(X_test)

That's it. You can use this code as a template for implementing Multiple Linear Regression in any dataset. For a better understanding with an example, Visit: Linear Regression with an example

PowerShell: Create Local User Account

As of PowerShell 5.1 there cmdlet New-LocalUser which could create local user account.

Example of usage:

Create a user account

New-LocalUser -Name "User02" -Description "Description of this account." -NoPassword

or Create a user account that has a password

$Password = Read-Host -AsSecureString
New-LocalUser "User03" -Password $Password -FullName "Third User" -Description "Description of this account."

or Create a user account that is connected to a Microsoft account

New-LocalUser -Name "MicrosoftAccount\usr [email protected]" -Description "Description of this account." 

Catch checked change event of a checkbox

Use below code snippet to achieve this.:

$('#checkAll').click(function(){
  $("#checkboxes input").attr('checked','checked');
});

$('#UncheckAll').click(function(){
  $("#checkboxes input").attr('checked',false);
});

Or you can do the same with single check box:

$('#checkAll').click(function(e) {
  if($('#checkAll').attr('checked') == 'checked') {
    $("#checkboxes input").attr('checked','checked');
    $('#checkAll').val('off');
  } else {
    $("#checkboxes input").attr('checked', false);
    $('#checkAll').val('on'); 
  }
});

For demo: http://jsfiddle.net/creativegala/hTtxe/

Get and Set a Single Cookie with Node.js HTTP Server

Let me repeat this part of question that answers here are ignoring:

Can it be done in a few lines of code, without the need to pull in a third party lib?


Reading Cookies

Cookies are read from requests with the Cookie header. They only include a name and value. Because of the way paths work, multiple cookies of the same name can be sent. In NodeJS, all Cookies in as one string as they are sent in the Cookie header. You split them with ;. Once you have a cookie, everything to the left of the equals (if present) is the name, and everything after is the value. Some browsers will accept a cookie with no equal sign and presume the name blank. Whitespaces do not count as part of the cookie. Values can also be wrapped in double quotes ("). Values can also contain =. For example, formula=5+3=8 is a valid cookie.

/**
 * @param {string} [cookieString='']
 * @return {[string,string][]} String Tuple
 */
function getEntriesFromCookie(cookieString = '') {
  return cookieString.split(';').map((pair) => {
    const indexOfEquals = pair.indexOf('=');
    let name;
    let value;
    if (indexOfEquals === -1) {
      name = '';
      value = pair.trim();
    } else {
      name = pair.substr(0, indexOfEquals).trim();
      value = pair.substr(indexOfEquals + 1).trim();
    }
    const firstQuote = value.indexOf('"');
    const lastQuote = value.lastIndexOf('"');
    if (firstQuote !== -1 && lastQuote !== -1) {
      value = value.substring(firstQuote + 1, lastQuote);
    }
    return [name, value];
  });
}

const cookieEntries = getEntriesFromCookie(request.headers.Cookie); 
const object = Object.fromEntries(cookieEntries.slice().reverse());

If you're not expecting duplicated names, then you can convert to an object which makes things easier. Then you can access like object.myCookieName to get the value. If you are expecting duplicates, then you want to do iterate through cookieEntries. Browsers feed cookies in descending priority, so reversing ensures the highest priority cookie appears in the object. (The .slice() is to avoid mutation of the array.)


Settings Cookies

"Writing" cookies is done by using the Set-Cookie header in your response. The response.headers['Set-Cookie'] object is actually an array, so you'll be pushing to it. It accepts a string but has more values than just name and value. The hardest part is writing the string, but this can be done in one line.

/**
 * @param {Object} options
 * @param {string} [options.name='']
 * @param {string} [options.value='']
 * @param {Date} [options.expires]
 * @param {number} [options.maxAge]
 * @param {string} [options.domain]
 * @param {string} [options.path]
 * @param {boolean} [options.secure]
 * @param {boolean} [options.httpOnly]
 * @param {'Strict'|'Lax'|'None'} [options.sameSite]
 * @return {string}
 */
function createSetCookie(options) {
  return (`${options.name || ''}=${options.value || ''}`)
    + (options.expires != null ? `; Expires=${options.expires.toUTCString()}` : '')
    + (options.maxAge != null ? `; Max-Age=${options.maxAge}` : '')
    + (options.domain != null ? `; Domain=${options.domain}` : '')
    + (options.path != null ? `; Path=${options.path}` : '')
    + (options.secure ? '; Secure' : '')
    + (options.httpOnly ? '; HttpOnly' : '')
    + (options.sameSite != null ? `; SameSite=${options.sameSite}` : '');
}

const newCookie = createSetCookie({
  name: 'cookieName',
  value: 'cookieValue',
  path:'/',
});
response.headers['Set-Cookie'].push(newCookie);

Remember you can set multiple cookies, because you can actually set multiple Set-Cookie headers in your request. That's why it's an array.


Note on external libraries:

If you decide to use the express, cookie-parser, or cookie, note they have defaults that are non-standard. Cookies parsed are always URI Decoded (percent-decoded). That means if you use a name or value that has any of the following characters: !#$%&'()*+/:<=>?@[]^`{|} they will be handled differently with those libraries. If you're setting cookies, they are encoded with %{HEX}. And if you're reading a cookie you have to decode them.

For example, while [email protected] is a valid cookie, these libraries will encode it as email=name%40domain.com. Decoding can exhibit issues if you are using the % in your cookie. It'll get mangled. For example, your cookie that was: secretagentlevel=50%007and50%006 becomes secretagentlevel=507and506. That's an edge case, but something to note if switching libraries.

Also, on these libraries, cookies are set with a default path=/ which means they are sent on every url request to the host.

If you want to encode or decode these values yourself, you can use encodeURIComponent or decodeURIComponent, respectively.


References:


Additional information:

show distinct column values in pyspark dataframe: python

collect_set can help to get unique values from a given column of pyspark.sql.DataFrame df.select(F.collect_set("column").alias("column")).first()["column"]

Powershell Get-ChildItem most recent file in directory

You could try to sort descending "sort LastWriteTime -Descending" and then "select -first 1." Not sure which one is faster

how to generate web service out of wsdl

How about using the wsdl /server or wsdl /serverinterface switches? As far as I understand the wsdl.exe command line properties, that's what you're looking for.

- ADVANCED -

/server

Server switch has been deprecated. Please use /serverInterface instead.
Generate an abstract class for an xml web service implementation using
ASP.NET based on the contracts. The default is to generate client proxy
classes.

On the other hand: why do you want to create obsolete technology solutions? Why not create this web service as a WCF service. That's the current and more modern, much more flexible way to do this!

Marc


UPDATE:

When I use wsdl /server on a WSDL file, I get this file created:

[WebService(Namespace="http://.......")]
public abstract partial class OneCrmServiceType : System.Web.Services.WebService 
{
    /// <remarks/>
    [WebMethod]
    public abstract void OrderCreated(......);
}

This is basically almost exactly the same code that gets generated when you add an ASMX file to your solution (in the code behind file - "yourservice.asmx.cs"). I don't think you can get any closer to creating an ASMX file from a WSDL file.

You can always add the "yourservice.asmx" manually - it doesn't really contain much:

<%@ WebService Language="C#" CodeBehind="YourService.asmx.cs" 
      Class="YourServiceNamespace.YourServiceClass" %>

fatal: Not a valid object name: 'master'

When I git init a folder it doesn't create a master branch

This is true, and expected behaviour. Git will not create a master branch until you commit something.

When I do git --bare init it creates the files.

A non-bare git init will also create the same files, in a hidden .git directory in the root of your project.

When I type git branch master it says "fatal: Not a valid object name: 'master'"

That is again correct behaviour. Until you commit, there is no master branch.

You haven't asked a question, but I'll answer the question I assumed you mean to ask. Add one or more files to your directory, and git add them to prepare a commit. Then git commit to create your initial commit and master branch.

Proper way to restrict text input values (e.g. only numbers)

Below is working solution using NgModel

Add variable

 public Phone:string;

In html add

      <input class="input-width" [(ngModel)]="Phone" (keyup)="keyUpEvent($event)" 
      type="text" class="form-control" placeholder="Enter Mobile Number">

In Ts file

   keyUpEvent(event: any) {
    const pattern = /[0-9\+\-\ ]/;  
    let inputChar = String.fromCharCode(event.keyCode);

    if (!pattern.test(inputChar)) {
      // invalid character, prevent input
      if(this.Phone.length>0)
      {
        this.Phone= this.Phone.substr(0,this.Phone.length-1);
      }
    }
  }

Get jQuery version from inspecting the jQuery object

$()['jquery']

Invoke console.log($()) and take note about jquery object fields :

  • jquery
  • selector
  • prevObject

enter image description here

ls command: how can I get a recursive full-path listing, one line per file?

If the directory is passed as a relative path and you will need to convert it to an absolute path before calling find. In the following example, the directory is passed as the first parameter to the script:

#!/bin/bash

# get absolute path
directory=`cd $1; pwd`
# print out list of files and directories
find $directory

Can I get JSON to load into an OrderedDict?

Some great news! Since version 3.6 the cPython implementation has preserved the insertion order of dictionaries (https://mail.python.org/pipermail/python-dev/2016-September/146327.html). This means that the json library is now order preserving by default. Observe the difference in behaviour between python 3.5 and 3.6. The code:

import json
data = json.loads('{"foo":1, "bar":2, "fiddle":{"bar":2, "foo":1}}')
print(json.dumps(data, indent=4))

In py3.5 the resulting order is undefined:

{
    "fiddle": {
        "bar": 2,
        "foo": 1
    },
    "bar": 2,
    "foo": 1
}

In the cPython implementation of python 3.6:

{
    "foo": 1,
    "bar": 2,
    "fiddle": {
        "bar": 2,
        "foo": 1
    }
}

The really great news is that this has become a language specification as of python 3.7 (as opposed to an implementation detail of cPython 3.6+): https://mail.python.org/pipermail/python-dev/2017-December/151283.html

So the answer to your question now becomes: upgrade to python 3.6! :)

The given key was not present in the dictionary. Which key?

You can try this code

Dictionary<string,string> AllFields = new Dictionary<string,string>();  
string value = (AllFields.TryGetValue(key, out index) ? AllFields[key] : null);

If the key is not present, it simply returns a null value.

Getting Error - ORA-01858: a non-numeric character was found where a numeric was expected

I added TO_DATE and it resolved issue.

Before modification - due to below condition i got this error

record_update_dt>='05-May-2017'

After modification - after adding to_date, issue got resolved.

record_update_dt>=to_date('05-May-2017','DD-Mon-YYYY')

Uncaught Typeerror: cannot read property 'innerHTML' of null

var idPost=document.getElementById("status").innerHTML;

The 'status' element does not exist in your webpage.

So document.getElementById("status") return null. While you can not use innerHTML property of NULL.

You should add a condition like this:

if(document.getElementById("status") != null){
    var idPost=document.getElementById("status").innerHTML;
}

Hope this answer can help you. :)

Best way to add Activity to an Android project in Eclipse?

An easy method suggested by Google Android Developer Community.

enter image description here

matplotlib: how to draw a rectangle on image

You can add a Rectangle patch to the matplotlib Axes.

For example (using the image from the tutorial here):

import matplotlib.pyplot as plt
import matplotlib.patches as patches
from PIL import Image

im = Image.open('stinkbug.png')

# Create figure and axes
fig, ax = plt.subplots()

# Display the image
ax.imshow(im)

# Create a Rectangle patch
rect = patches.Rectangle((50, 100), 40, 30, linewidth=1, edgecolor='r', facecolor='none')

# Add the patch to the Axes
ax.add_patch(rect)

plt.show()

enter image description here

Is there an eval() function in Java?

I could advise you to use Exp4j. It is easy to understand as you can see from the following example code:

Expression e = new ExpressionBuilder("3 * sin(y) - 2 / (x - 2)")
    .variables("x", "y")
    .build()
    .setVariable("x", 2.3)
    .setVariable("y", 3.14);
double result = e.evaluate();

Failed to execute 'btoa' on 'Window': The string to be encoded contains characters outside of the Latin1 range.

Using btoa with unescape and encodeURIComponent didn't work for me. Replacing all the special characters with XML/HTML entities and then converting to the base64 representation was the only way to solve this issue for me. Some code:

base64 = btoa(str.replace(/[\u00A0-\u2666]/g, function(c) {
    return '&#' + c.charCodeAt(0) + ';';
}));

Use RSA private key to generate public key?

openssl genrsa -out mykey.pem 1024

will actually produce a public - private key pair. The pair is stored in the generated mykey.pem file.

openssl rsa -in mykey.pem -pubout > mykey.pub

will extract the public key and print that out. Here is a link to a page that describes this better.

EDIT: Check the examples section here. To just output the public part of a private key:

openssl rsa -in key.pem -pubout -out pubkey.pem

To get a usable public key for SSH purposes, use ssh-keygen:

ssh-keygen -y -f key.pem > key.pub

How to display tables on mobile using Bootstrap?

Bootstrap 3 introduces responsive tables:

<div class="table-responsive">
  <table class="table">
    ...
  </table>
</div>

Bootstrap 4 is similar, but with more control via some new classes:

...responsive across all viewports ... with .table-responsive. Or, pick a maximum breakpoint with which to have a responsive table up to by using .table-responsive{-sm|-md|-lg|-xl}.

Credit to Jason Bradley for providing an example:

Responsive Tables

How can I send mail from an iPhone application

A few things I'd like to add here:

  1. Using the mailto URL won't work in the simulator as mail.app isn't installed on the simulator. It does work on device though.

  2. There is a limit to the length of the mailto URL. If the URL is larger than 4096 characters, mail.app won't launch.

  3. There is a new class in OS 3.0 that lets you send an e-mail without leaving your app. See the class MFMailComposeViewController.

regular expression for anything but an empty string

I think [ ]{4} might work in the example where you need to detect 4 spaces. Same with the rest: [ ]{1}, [ ]{2} and [ ]{3}. If you want to detect an empty string in general, ^[ ]*$ will do.

CORS error :Request header field Authorization is not allowed by Access-Control-Allow-Headers in preflight response

If you don't want to install the cors library and instead want to fix your original code, the other step you are missing is that Access-Control-Allow-Origin:* is wrong. When passing Authentication tokens (e.g. JWT) then you must explicitly state every url that is calling your server. You can't use "*" when doing authentication tokens.

Set default time in bootstrap-datetimepicker

Momentjs.com has good documentation on how to manipulate the date/time in relation to the current moment. Since Momentjs is required for the Datetimepicker, might as well use it.

var startDefault = moment().startof('day').add(1, 'minutes');
$('#startdatetime-from').datetimepicker({
    defaultDate: startDefault,
    language: 'en',
    format: 'yyyy-MM-dd hh:mm'
});

In SQL, how can you "group by" in ranges?

An alternative approach would involve storing the ranges in a table, instead of embedding them in the query. You would end up with a table, call it Ranges, that looks like this:

LowerLimit   UpperLimit   Range 
0              9          '0-9'
10            19          '10-19'
20            29          '20-29'
30            39          '30-39'

And a query that looks like this:

Select
   Range as [Score Range],
   Count(*) as [Number of Occurences]
from
   Ranges r inner join Scores s on s.Score between r.LowerLimit and r.UpperLimit
group by Range

This does mean setting up a table, but it would be easy to maintain when the desired ranges change. No code changes necessary!

R error "sum not meaningful for factors"

The error comes when you try to call sum(x) and x is a factor.

What that means is that one of your columns, though they look like numbers are actually factors (what you are seeing is the text representation)

simple fix, convert to numeric. However, it needs an intermeidate step of converting to character first. Use the following:

family[, 1] <- as.numeric(as.character( family[, 1] ))
family[, 3] <- as.numeric(as.character( family[, 3] ))

For a detailed explanation of why the intermediate as.character step is needed, take a look at this question: How to convert a factor to integer\numeric without loss of information?

How can I wait for a thread to finish with .NET?

Here's a simple example that waits for a tread to finish, within the same class. It also makes a call to another class in the same namespace. I included the "using" statements so it can execute as a Windows Forms form as long as you create button1.

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Threading;

namespace ClassCrossCall
{

    public partial class Form1 : Form
    {
        int number = 0; // This is an intentional problem, included
                        // for demonstration purposes
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            button1.Text = "Initialized";
        }

        private void button1_Click(object sender, EventArgs e)
        {
            button1.Text = "Clicked";
            button1.Refresh();
            Thread.Sleep(400);
            List<Task> taskList = new List<Task>();
            taskList.Add(Task.Factory.StartNew(() => update_thread(2000)));
            taskList.Add(Task.Factory.StartNew(() => update_thread(4000)));
            Task.WaitAll(taskList.ToArray());
            worker.update_button(this, number);
        }

        public void update_thread(int ms)
        {
            // It's important to check the scope of all variables
            number = ms; // This could be either 2000 or 4000. Race condition.
            Thread.Sleep(ms);
        }
    }

    class worker
    {
        public static void update_button(Form1 form, int number)
        {
            form.button1.Text = $"{number}";
        }
    }
}

How to convert from java.sql.Timestamp to java.util.Date?

java.sql.ResultSet rs;
//fill rs somehow
java.sql.Timestamp timestamp = rs.getTimestamp(1); //get first column
long milliseconds = timestamp.getTime() + (timestamp.getNanos() / 1000000);
java.util.Date date = return new java.util.Date(milliseconds);

Eclipse will not start and I haven't changed anything

Definitely a network/proxy thing. I connect via wifi and a corporate gateway. Deleted workspace, reinstalled GGTS - still hangs. Turn off the network - launches fine.

Objective-C - Remove last character from string

The solutions given here actually do not take into account multi-byte Unicode characters ("composed characters"), and could result in invalid Unicode strings.

In fact, the iOS header file which contains the declaration of substringToIndex contains the following comment:

Hint: Use with rangeOfComposedCharacterSequencesForRange: to avoid breaking up composed characters

See how to use rangeOfComposedCharacterSequenceAtIndex: to delete the last character correctly.

How to set recurring schedule for xlsm file using Windows Task Scheduler

Better to use a as you indicated

  1. Create a simple vbs, which is a text file with a .vbs extension (see sample code below)
  2. Use the Task Scheduler to run the vbs
  3. Use the vbs to open the workbook at the scheduled time and then either:
    • use the Private Sub Workbook_Open() event in the ThisWorkbook module to run code when the file is opened
    • more robustly (as macros may be disabled on open), use Application.Run in the vbs to run the macro

See this example of the later approach at Running Excel on Windows Task Scheduler

sample vbs

Dim ObjExcel, ObjWB
Set ObjExcel = CreateObject("excel.application")
'vbs opens a file specified by the path below
Set ObjWB = ObjExcel.Workbooks.Open("C:\temp\rod.xlsm")
'either use the Workbook Open event (if macros are enabled), or Application.Run

ObjWB.Close False
ObjExcel.Quit
Set ObjExcel = Nothing

How to move a git repository into another directory and make that directory a git repository?

To do this without any headache:

  1. Check out what's the current branch in the gitrepo1 with git status, let's say branch "development".
  2. Change directory to the newrepo, then git clone the project from repository.
  3. Switch branch in newrepo to the previous one: git checkout development.
  4. Syncronize newrepo with the older one, gitrepo1 using rsync, excluding .git folder: rsync -azv --exclude '.git' gitrepo1 newrepo/gitrepo1. You don't have to do this with rsync of course, but it does it so smooth.

The benefit of this approach: you are good to continue exactly where you left off: your older branch, unstaged changes, etc.

Explain the different tiers of 2 tier & 3 tier architecture?

First, we must make a distinction between layers and tiers. Layers are the way to logically break code into components and tiers are the physical nodes to place the components on. This question explains it better: What's the difference between "Layers" and "Tiers"?

A two layer architecture is usually just a presentation layer and data store layer. These can be on 1 tier (1 machine) or 2 tiers (2 machines) to achieve better performance by distributing the work load.

A three layer architecture usually puts something between the presentation and data store layers such as a business logic layer or service layer. Again, you can put this into 1,2, or 3 tiers depending on how much money you have for hardware and how much load you expect.

Putting multiple machines in a tier will help with the robustness of the system by providing redundancy.

Below is a good example of a layered architecture:

alt text
(source: microsoft.com)

A good reference for all of this can be found here on MSDN: http://msdn.microsoft.com/en-us/library/ms978678.aspx

What does "for" attribute do in HTML <label> tag?

The <label> tag allows you to click on the label, and it will be treated like clicking on the associated input element. There are two ways to create this association:

One way is to wrap the label element around the input element:

<label>Input here:
    <input type='text' name='theinput' id='theinput'>
</label>

The other way is to use the for attribute, giving it the ID of the associated input:

<label for="theinput">Input here:</label>
<input type='text' name='whatever' id='theinput'>

This is especially useful for use with checkboxes and buttons, since it means you can check the box by clicking on the associated text instead of having to hit the box itself.

Read more about this element in MDN.

Simple way to sort strings in the (case sensitive) alphabetical order

If you don't want to add a dependency on Guava (per Michael's answer) then this comparator is equivalent:

private static Comparator<String> ALPHABETICAL_ORDER = new Comparator<String>() {
    public int compare(String str1, String str2) {
        int res = String.CASE_INSENSITIVE_ORDER.compare(str1, str2);
        if (res == 0) {
            res = str1.compareTo(str2);
        }
        return res;
    }
};

Collections.sort(list, ALPHABETICAL_ORDER);

And I think it is just as easy to understand and code ...

The last 4 lines of the method can written more concisely as follows:

        return (res != 0) ? res : str1.compareTo(str2);

How do I get a YouTube video thumbnail from the YouTube API?

You can get the Video Entry which contains the URL to the video's thumbnail. There's example code in the link. Or, if you want to parse XML, there's information here. The XML returned has a media:thumbnail element, which contains the thumbnail's URL.

Convert string to buffer Node

You can use Buffer.from() to convert a string to buffer. More information on this can be found here

var buf = Buffer.from('some string', 'encoding');

for example

var buf = Buffer.from(bStr, 'utf-8');

jQuery find element by data attribute value

Use Attribute Equals Selector

$('.slide-link[data-slide="0"]').addClass('active');

Fiddle Demo

.find()

it works down the tree

Get the descendants of each element in the current set of matched elements, filtered by a selector, jQuery object, or element.

How to backup MySQL database in PHP?

From the answer of @DevWL, I got "Undefined offset ..." at

if ($j<($num_fields-1)) { $data.= ','; }

I made some changes to:

  • preserve relationships (foreign keys)
  • use Transactions
  • remove the uneedy $num_fields

class DBbackup {
 public $suffix;
 public $dirs;
 protected $dbInstance;
 public function __construct() {
   try{
    $this->dbInstance = new PDO("mysql:host=".$dbhost.";dbname=".$dbname, 
    $username, $password);
  } catch(Exception $e) {
    die("Error ".$e->getMessage());
  }
   $this->suffix = date('Ymd_His');
 }

 public function backup($tables = '*'){
   $output = "-- database backup - ".date('Y-m-d H:i:s').PHP_EOL;
   $output .= "SET NAMES utf8;".PHP_EOL;
   $output .= "SET sql_mode = 'NO_AUTO_VALUE_ON_ZERO';".PHP_EOL;
   $output .= "SET foreign_key_checks = 0;".PHP_EOL;
   $output .= "SET AUTOCOMMIT = 0;".PHP_EOL;
   $output .= "START TRANSACTION;".PHP_EOL;
   //get all table names
   if($tables == '*') {
     $tables = [];
     $query = $this->dbInstance->prepare('SHOW TABLES');
     $query->execute();
     while($row = $query->fetch(PDO::FETCH_NUM)) {
       $tables[] = $row[0];
     }
     $query->closeCursor();
   }
   else {
     $tables = is_array($tables) ? $tables : explode(',',$tables);
   }

   foreach($tables as $table) {

     $query = $this->dbInstance->prepare("SELECT * FROM `$table`");
     $query->execute();
     $output .= "DROP TABLE IF EXISTS `$table`;".PHP_EOL;

     $query2 = $this->dbInstance->prepare("SHOW CREATE TABLE `$table`");
     $query2->execute();
     $row2 = $query2->fetch(PDO::FETCH_NUM);
     $query2->closeCursor();
     $output .= PHP_EOL.$row2[1].";".PHP_EOL;

       while($row = $query->fetch(PDO::FETCH_NUM)) {
         $output .= "INSERT INTO `$table` VALUES(";
         for($j=0; $j<count($row); $j++) {
           $row[$j] = addslashes($row[$j]);
           $row[$j] = str_replace("\n","\\n",$row[$j]);
           if (isset($row[$j]))
             $output .= "'".$row[$j]."'";
           else $output .= "''";
           if ($j<(count($row)-1))
            $output .= ',';
         }
         $output .= ");".PHP_EOL;
       }
     }
     $output .= PHP_EOL.PHP_EOL;

   $output .= "COMMIT;";
   //save filename

   $filename = 'db_backup_'.$this->suffix.'.sql';
   $this->writeUTF8filename($filename,$output);
 }


 private function writeUTF8filename($fn,$c){  /* save as utf8 encoding */
   $f=fopen($fn,"w+");
   # Now UTF-8 - Add byte order mark
   fwrite($f, pack("CCC",0xef,0xbb,0xbf));
   fwrite($f,$c);
   fclose($f);
 }

}

And usage example:

$Backup = new DBbackup();
$Backup->backup();

This works great on MySQL 10.1.34-MariaDB , PHP : 7.2.7

get current page from url

Request.Url.Segments.Last()

Another option.

How to place a div below another div?

what about changing the position: relative on your #content #text div to position: absolute

#content #text {
   position:absolute;
   width:950px;
   height:215px;
   color:red;
}

http://jsfiddle.net/CaZY7/12/

then you can use the css properties left and top to position within the #content div

How to remove package using Angular CLI?

You can use npm uninstall <package-name> will remove it from your package.json file and from node_modules.

If you do ng help command, you will see that there is no ng remove/delete supported command. So, basically you cannot revert the ng add behavior yet.

Abort trap 6 error in C

Try this:

void drawInitialNim(int num1, int num2, int num3){
    int board[3][50] = {0}; // This is a local variable. It is not possible to use it after returning from this function. 

    int i, j, k;

    for(i=0; i<num1; i++)
        board[0][i] = 'O';
    for(i=0; i<num2; i++)
        board[1][i] = 'O';
    for(i=0; i<num3; i++)
        board[2][i] = 'O';

    for (j=0; j<3;j++) {
        for (k=0; k<50; k++) {
            if(board[j][k] != 0)
                printf("%c", board[j][k]);
        }
        printf("\n");
    }
}

How do you get a query string on Flask?

The full URL is available as request.url, and the query string is available as request.query_string.decode().

Here's an example:

from flask import request

@app.route('/adhoc_test/')
def adhoc_test():

    return request.query_string

To access an individual known param passed in the query string, you can use request.args.get('param'). This is the "right" way to do it, as far as I know.

ETA: Before you go further, you should ask yourself why you want the query string. I've never had to pull in the raw string - Flask has mechanisms for accessing it in an abstracted way. You should use those unless you have a compelling reason not to.

How to run html file using node js

Just install http-server globally

npm install -g http-server

where ever you need to run a html file run the command http-server For ex: your html file is in /home/project/index.html you can do /home/project/$ http-server

That will give you a link to accessyour webpages: http-server Starting up http-server, serving ./ Available on: http://127.0.0.1:8080 http://192.168.0.106:8080

Load HTML File Contents to Div [without the use of iframes]

Wow, from all the framework-promotional answers you'd think this was something JavaScript made incredibly difficult. It isn't really.

var xhr= new XMLHttpRequest();
xhr.open('GET', 'x.html', true);
xhr.onreadystatechange= function() {
    if (this.readyState!==4) return;
    if (this.status!==200) return; // or whatever error handling you want
    document.getElementById('y').innerHTML= this.responseText;
};
xhr.send();

If you need IE<8 compatibility, do this first to bring those browsers up to speed:

if (!window.XMLHttpRequest && 'ActiveXObject' in window) {
    window.XMLHttpRequest= function() {
        return new ActiveXObject('MSXML2.XMLHttp');
    };
}

Note that loading content into the page with scripts will make that content invisible to clients without JavaScript available, such as search engines. Use with care, and consider server-side includes if all you want is to put data in a common shared file.

XSLT equivalent for JSON

I wrote a dom adapter for my jackson based json processing framework long time ago. It uses the nu.xom library. The resulting dom tree works with the java xpath and xslt facilities. I made some implementation choices that are pretty straightforward. For example the root node is always called "root", arrays go into an ol node with li sub elements (like in html), and everything else is just a sub node with a primitive value or another object node.

JsonXmlConverter.java

Usage: JsonObject sampleJson = sampleJson(); org.w3c.dom.Document domNode = JsonXmlConverter.getW3cDocument(sampleJson, "root");

VS2010 How to include files in project, to copy them to build output directory automatically during build or publish

There is and it is not dependent on post build events.

Add the file to your project, then in the file properties select under "Copy to Output Directory" either "Copy Always" or "Copy if Newer".

See MSDN.

Bootstrap: Collapse other sections when one is expanded

Bootstrap 3 example with side by side buttons below the content

_x000D_
_x000D_
.panel-heading {_x000D_
  display: inline-block;_x000D_
}_x000D_
_x000D_
.panel-group .panel+.panel {_x000D_
  margin: 0;_x000D_
  border: 0;_x000D_
}_x000D_
_x000D_
.panel {_x000D_
  border: 0 !important;_x000D_
  -webkit-box-shadow: none !important;_x000D_
  box-shadow: none !important;_x000D_
  background-color: transparent !important;_x000D_
}
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>_x000D_
_x000D_
<!-- Latest compiled and minified CSS -->_x000D_
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">_x000D_
_x000D_
<!-- Latest compiled and minified JavaScript -->_x000D_
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>_x000D_
_x000D_
_x000D_
<div class="panel-group" id="accordion">_x000D_
    <div class="panel panel-default">_x000D_
        <div id="collapse1" class="panel-collapse collapse in">_x000D_
            <div class="panel-body">Lorem ipsum dolor sit amet, consectetur adipisicing elit,_x000D_
        sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam,_x000D_
        quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.</div>_x000D_
        </div>_x000D_
    </div>_x000D_
    <div class="panel panel-default">_x000D_
        <div id="collapse2" class="panel-collapse collapse">_x000D_
            <div class="panel-body">Lorem ipsum dolor sit amet, consectetur adipisicing elit,_x000D_
        sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam,_x000D_
        quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.</div>_x000D_
        </div>_x000D_
    </div>_x000D_
    <div class="panel panel-default">_x000D_
        <div id="collapse3" class="panel-collapse collapse">_x000D_
            <div class="panel-body">Lorem ipsum dolor sit amet, consectetur adipisicing elit,_x000D_
        sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam,_x000D_
        quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.</div>_x000D_
        </div>_x000D_
    </div>_x000D_
</div>_x000D_
<div class="panel-heading">_x000D_
    <h4 class="panel-title">_x000D_
        <a data-toggle="collapse" data-parent="#accordion" href="#collapse1">Collapsible Group 1</a>_x000D_
    </h4>_x000D_
</div>_x000D_
<div class="panel-heading">_x000D_
    <h4 class="panel-title">_x000D_
        <a data-toggle="collapse" data-parent="#accordion" href="#collapse2">Collapsible Group 2</a>_x000D_
    </h4>_x000D_
</div>_x000D_
<div class="panel-heading">_x000D_
    <h4 class="panel-title">_x000D_
        <a data-toggle="collapse" data-parent="#accordion" href="#collapse3">Collaple Group 3</a>_x000D_
    </h4>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Bootstrap 3 example with side by side buttons above the content

_x000D_
_x000D_
.panel-heading {_x000D_
  display: inline-block;_x000D_
}_x000D_
_x000D_
.panel-group .panel+.panel {_x000D_
  margin: 0;_x000D_
  border: 0;_x000D_
}_x000D_
_x000D_
.panel {_x000D_
  border: 0 !important;_x000D_
  -webkit-box-shadow: none !important;_x000D_
  box-shadow: none !important;_x000D_
  background-color: transparent !important;_x000D_
}
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>_x000D_
_x000D_
<!-- Latest compiled and minified CSS -->_x000D_
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">_x000D_
_x000D_
<!-- Latest compiled and minified JavaScript -->_x000D_
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>_x000D_
_x000D_
<div class="panel-heading">_x000D_
    <h4 class="panel-title">_x000D_
        <a data-toggle="collapse" data-parent="#accordion" href="#collapse1">Collapsible Group 1</a>_x000D_
    </h4>_x000D_
</div>_x000D_
<div class="panel-heading">_x000D_
    <h4 class="panel-title">_x000D_
        <a data-toggle="collapse" data-parent="#accordion" href="#collapse2">Collapsible Group 2</a>_x000D_
    </h4>_x000D_
</div>_x000D_
<div class="panel-heading">_x000D_
    <h4 class="panel-title">_x000D_
        <a data-toggle="collapse" data-parent="#accordion" href="#collapse3">Collaple Group 3</a>_x000D_
    </h4>_x000D_
</div>_x000D_
<div class="panel-group" id="accordion">_x000D_
    <div class="panel panel-default">_x000D_
        <div id="collapse1" class="panel-collapse collapse in">_x000D_
            <div class="panel-body">Lorem ipsum dolor sit amet, consectetur adipisicing elit,_x000D_
        sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam,_x000D_
        quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.</div>_x000D_
        </div>_x000D_
    </div>_x000D_
    <div class="panel panel-default">_x000D_
        <div id="collapse2" class="panel-collapse collapse">_x000D_
            <div class="panel-body">Lorem ipsum dolor sit amet, consectetur adipisicing elit,_x000D_
        sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam,_x000D_
        quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.</div>_x000D_
        </div>_x000D_
    </div>_x000D_
    <div class="panel panel-default">_x000D_
        <div id="collapse3" class="panel-collapse collapse">_x000D_
            <div class="panel-body">Lorem ipsum dolor sit amet, consectetur adipisicing elit,_x000D_
        sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam,_x000D_
        quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.</div>_x000D_
        </div>_x000D_
    </div>_x000D_
</div>
_x000D_
_x000D_
_x000D_

SVN upgrade working copy

If you're getting this error from Netbeans (7.2+) then it means that your separately installed version of Subversion is higher than the version in netbeans. In my case Netbeans (v7.3.1) had SVN v1.7 and I'd just upgraded my SVN to v1.8.

If you look in Tools > Options > Miscellaneous (tab) > Versioning (tab) > Subversion (pane), set the Preferred Client = CLI, then you can set the path the the installed SVN which for me was C:\Program Files\TortoiseSVN\bin.

More can be found on the Netbeans Subversion Clients FAQ.

Grep characters before and after match?

3 characters before and 4 characters after

$> echo "some123_string_and_another" | grep -o -P '.{0,3}string.{0,4}'
23_string_and

Fast way to discover the row count of a table in PostgreSQL

How wide is the text column?

With a GROUP BY there's not much you can do to avoid a data scan (at least an index scan).

I'd recommend:

  1. If possible, changing the schema to remove duplication of text data. This way the count will happen on a narrow foreign key field in the 'many' table.

  2. Alternatively, creating a generated column with a HASH of the text, then GROUP BY the hash column. Again, this is to decrease the workload (scan through a narrow column index)

Edit:

Your original question did not quite match your edit. I'm not sure if you're aware that the COUNT, when used with a GROUP BY, will return the count of items per group and not the count of items in the entire table.

Why do we use arrays instead of other data structures?

For O(1) random access, which can not be beaten.

Java JDBC - How to connect to Oracle using Service Name instead of SID

When using dag instead of thin, the syntax below pointing to service name worked for me. The jdbc:thin solutions above did not work.

jdbc:dag:oracle://HOSTNAME:1521;ServiceName=SERVICE_NAME

Reverting single file in SVN to a particular revision

If it's only a couple of files, and if you're using Tortoise SVN, you can use the following approach:

  1. Right click on your source file, and select "TortoiseSVN" -> "Show log".
  2. Right click on a revision in the log, and select "Save revision to...".
  3. Let the old revision overwrite your current file.
  4. Commit the overwritten source file.

c++ "Incomplete type not allowed" error accessing class reference information (Circular dependency with forward declaration)

Player.cpp require the definition of Ball class. So simply add #include "Ball.h"

Player.cpp:

#include "Player.h"
#include "Ball.h"

void Player::doSomething(Ball& ball) {
    ball.ballPosX += 10;                   // incomplete type error occurs here.
}

'App not Installed' Error on Android

My problem was that I have multiple user accounts on the device. I deleted the app on 1 account, but it still was installed on the other account. Thus the namespace collided and did not install. Uninstalling the app from all user fixed it for me.

How do I specify C:\Program Files without a space in it for programs that can't handle spaces in file paths?

you should be able to use

  • "c:\Program Files" (note the quotes)
  • c:\PROGRA~1 (the short name notation)

Try c:\> dir /x (in dos shell)

This displays the short names generated for non-8dot3 file names. The format is that of /N with the short name inserted before the long name. If no short name is present, blanks are displayed in its place.

Strip off URL parameter with PHP

Here is the actual code for what's described above as the "the safest 'correct' method"...

function reduce_query($uri = '') {
    $kill_params = array('gclid');

    $uri_array = parse_url($uri);
    if (isset($uri_array['query'])) {
        // Do the chopping.
        $params = array();
        foreach (explode('&', $uri_array['query']) as $param) {
          $item = explode('=', $param);
          if (!in_array($item[0], $kill_params)) {
            $params[$item[0]] = isset($item[1]) ? $item[1] : '';
          }
        }
        // Sort the parameter array to maximize cache hits.
        ksort($params);
        // Build new URL (no hosts, domains, or fragments involved).
        $new_uri = '';
        if ($uri_array['path']) {
          $new_uri = $uri_array['path'];
        }
        if (count($params) > 0) {
          // Wish there was a more elegant option.
          $new_uri .= '?' . urldecode(http_build_query($params));
        }
        return $new_uri;
    }
    return $uri;
}

$_SERVER['REQUEST_URI'] = reduce_query($_SERVER['REQUEST_URI']);

However, since this will likely exist prior to the bootstrap of your application, you should probably put it into an anonymous function. Like this...

call_user_func(function($uri) {
    $kill_params = array('gclid');

    $uri_array = parse_url($uri);
    if (isset($uri_array['query'])) {
        // Do the chopping.
        $params = array();
        foreach (explode('&', $uri_array['query']) as $param) {
          $item = explode('=', $param);
          if (!in_array($item[0], $kill_params)) {
            $params[$item[0]] = isset($item[1]) ? $item[1] : '';
          }
        }
        // Sort the parameter array to maximize cache hits.
        ksort($params);
        // Build new URL (no hosts, domains, or fragments involved).
        $new_uri = '';
        if ($uri_array['path']) {
          $new_uri = $uri_array['path'];
        }
        if (count($params) > 0) {
          // Wish there was a more elegant option.
          $new_uri .= '?' . urldecode(http_build_query($params));
        }
        // Update server variable.
        $_SERVER['REQUEST_URI'] = $new_uri;

    }
}, $_SERVER['REQUEST_URI']);

NOTE: Updated with urldecode() to avoid double encoding via http_build_query() function. NOTE: Updated with ksort() to allow params with no value without an error.

How to combine two lists in R

We can use append

append(l1, l2)

It also has arguments to insert element at a particular location.

Using the Underscore module with Node.js

The name _ used by the node.js REPL to hold the previous input. Choose another name.

How to Set/Update State of StatefulWidget from other StatefulWidget in Flutter?

Here is the solution which worked for me.

OUTPUT: State of Cart Widget is updated, upon addition of items.

enter image description here

Create a globalKey for the widget you want to update by calling the trigger from anywhere

final GlobalKey<CartWidgetState> cartKey = GlobalKey();

Make sure it's saved in a file have global access such that, it can be accessed from anywhere. I save it in globalClass where is save commonly used variables through the app's state.

class CartWidget extends StatefulWidget {

  CartWidget({Key key}) : super(key: key);
  @override
  CartWidgetState createState() => CartWidgetState();
}

class CartWidgetState extends State<CartWidget> {
  @override
  Widget build(BuildContext context) {
    //return your widget
    return Container();
  }
}

Call your widget from some other class.

class HomeScreen extends StatefulWidget {

  HomeScreen ({Key key}) : super(key: key);
  @override
  HomeScreenState createState() => HomeScreen State();
}

class HomeScreen State extends State<HomeScreen> {
  @override
  Widget build(BuildContext context) {
    return ListView(
              children:[
                 ChildScreen(), 
                 CartWidget(key:cartKey)
              ]
            );
  }
}



class ChildScreen extends StatefulWidget {

  ChildScreen ({Key key}) : super(key: key);
  @override
  ChildScreenState createState() => ChildScreen State();
}

class ChildScreen State extends State<ChildScreen> {
  @override
  Widget build(BuildContext context) {
    return InkWell(
              onTap: (){
                // This will update the state of your inherited widget/ class
                if (cartKey.currentState != null)
                    cartKey.currentState.setState(() {});
              },
              child: Text("Update The State of external Widget"),
           );
  }
}

ArithmeticException: "Non-terminating decimal expansion; no exact representable decimal result"

I had this same problem, because my line of code was:

txtTotalInvoice.setText(var1.divide(var2).doubleValue() + "");

I change to this, reading previous Answer, because I was not writing decimal precision:

txtTotalInvoice.setText(var1.divide(var2,4, RoundingMode.HALF_UP).doubleValue() + "");

4 is Decimal Precison

AND RoundingMode are Enum constants, you could choose any of this UP, DOWN, CEILING, FLOOR, HALF_DOWN, HALF_EVEN, HALF_UP

In this Case HALF_UP, will have this result:

2.4 = 2   
2.5 = 3   
2.7 = 3

You can check the RoundingMode information here: http://www.javabeat.net/precise-rounding-of-decimals-using-rounding-mode-enumeration/

Getting a link to go to a specific section on another page

I believe the example you've posted is using HTML5, which allows you to jump to any DOM element with the matching ID attribute. To support older browsers, you'll need to change:

<div id="timeline" name="timeline" ...>

To the old format:

<a name="timeline" />

You'll then be able to navigate to /academics/page.html#timeline and jump right to that section.

Also, check out this similar question.

Accessing members of items in a JSONArray with Java

In case it helps someone else, I was able to convert to an array by doing something like this,

JSONObject jsonObject = (JSONObject)new JSONParser().parse(jsonString);
((JSONArray) jsonObject).toArray()

...or you should be able to get the length

((JSONArray) myJsonArray).toArray().length

What is the difference between Nexus and Maven?

This has a good general description: https://gephi.wordpress.com/tag/maven/

Let me make a few statement that can put the difference in focus:

  1. We migrated our code base from Ant to Maven

  2. All 3rd party librairies have been uploaded to Nexus. Maven is using Nexus as a source for libraries.

  3. Basic functionalities of a repository manager like Sonatype are:

    • Managing project dependencies,
    • Artifacts & Metadata,
    • Proxying external repositories
    • and deployment of packaged binaries and JARs to share those artifacts with other developers and end-users.

Temporarily change current working directory in bash to run a command

You can run the cd and the executable in a subshell by enclosing the command line in a pair of parentheses:

(cd SOME_PATH && exec_some_command)

Demo:

$ pwd
/home/abhijit
$ (cd /tmp && pwd)  # directory changed in the subshell
/tmp 
$ pwd               # parent shell's pwd is still the same
/home/abhijit

How to select count with Laravel's fluent query builder?

You can use an array in the select() to define more columns and you can use the DB::raw() there with aliasing it to followers. Should look like this:

$query = DB::table('category_issue')
    ->select(array('issues.*', DB::raw('COUNT(issue_subscriptions.issue_id) as followers')))
    ->where('category_id', '=', 1)
    ->join('issues', 'category_issue.issue_id', '=', 'issues.id')
    ->left_join('issue_subscriptions', 'issues.id', '=', 'issue_subscriptions.issue_id')
    ->group_by('issues.id')
    ->order_by('followers', 'desc')
    ->get();

What exactly is std::atomic?

Each instantiation and full specialization of std::atomic<> represents a type that different threads can simultaneously operate on (their instances), without raising undefined behavior:

Objects of atomic types are the only C++ objects that are free from data races; that is, if one thread writes to an atomic object while another thread reads from it, the behavior is well-defined.

In addition, accesses to atomic objects may establish inter-thread synchronization and order non-atomic memory accesses as specified by std::memory_order.

std::atomic<> wraps operations that, in pre-C++ 11 times, had to be performed using (for example) interlocked functions with MSVC or atomic bultins in case of GCC.

Also, std::atomic<> gives you more control by allowing various memory orders that specify synchronization and ordering constraints. If you want to read more about C++ 11 atomics and memory model, these links may be useful:

Note that, for typical use cases, you would probably use overloaded arithmetic operators or another set of them:

std::atomic<long> value(0);
value++; //This is an atomic op
value += 5; //And so is this

Because operator syntax does not allow you to specify the memory order, these operations will be performed with std::memory_order_seq_cst, as this is the default order for all atomic operations in C++ 11. It guarantees sequential consistency (total global ordering) between all atomic operations.

In some cases, however, this may not be required (and nothing comes for free), so you may want to use more explicit form:

std::atomic<long> value {0};
value.fetch_add(1, std::memory_order_relaxed); // Atomic, but there are no synchronization or ordering constraints
value.fetch_add(5, std::memory_order_release); // Atomic, performs 'release' operation

Now, your example:

a = a + 12;

will not evaluate to a single atomic op: it will result in a.load() (which is atomic itself), then addition between this value and 12 and a.store() (also atomic) of final result. As I noted earlier, std::memory_order_seq_cst will be used here.

However, if you write a += 12, it will be an atomic operation (as I noted before) and is roughly equivalent to a.fetch_add(12, std::memory_order_seq_cst).

As for your comment:

A regular int has atomic loads and stores. Whats the point of wrapping it with atomic<>?

Your statement is only true for architectures that provide such guarantee of atomicity for stores and/or loads. There are architectures that do not do this. Also, it is usually required that operations must be performed on word-/dword-aligned address to be atomic std::atomic<> is something that is guaranteed to be atomic on every platform, without additional requirements. Moreover, it allows you to write code like this:

void* sharedData = nullptr;
std::atomic<int> ready_flag = 0;

// Thread 1
void produce()
{
    sharedData = generateData();
    ready_flag.store(1, std::memory_order_release);
}

// Thread 2
void consume()
{
    while (ready_flag.load(std::memory_order_acquire) == 0)
    {
        std::this_thread::yield();
    }

    assert(sharedData != nullptr); // will never trigger
    processData(sharedData);
}

Note that assertion condition will always be true (and thus, will never trigger), so you can always be sure that data is ready after while loop exits. That is because:

  • store() to the flag is performed after sharedData is set (we assume that generateData() always returns something useful, in particular, never returns NULL) and uses std::memory_order_release order:

memory_order_release

A store operation with this memory order performs the release operation: no reads or writes in the current thread can be reordered after this store. All writes in the current thread are visible in other threads that acquire the same atomic variable

  • sharedData is used after while loop exits, and thus after load() from flag will return a non-zero value. load() uses std::memory_order_acquire order:

std::memory_order_acquire

A load operation with this memory order performs the acquire operation on the affected memory location: no reads or writes in the current thread can be reordered before this load. All writes in other threads that release the same atomic variable are visible in the current thread.

This gives you precise control over the synchronization and allows you to explicitly specify how your code may/may not/will/will not behave. This would not be possible if only guarantee was the atomicity itself. Especially when it comes to very interesting sync models like the release-consume ordering.

How to use su command over adb shell?

The su command does not execute anything, it just raise your privileges.

Try adb shell su -c YOUR_COMMAND.

Warning: implode() [function.implode]: Invalid arguments passed

You are getting the error because $ret is not an array.

To get rid of the error, at the start of your function, define it with this line: $ret = array();

It appears that the get_tags() call is returning nothing, so the foreach is not run, which means that $ret isn't defined.

Common CSS Media Queries Break Points

I can tell you I am using just a single breakpoint at 768 - that is min-width: 768px to serve tablets and desktops, and max-width: 767px to serve phones.

I haven't looked back since. It makes the responsive development easy and not a chore, and provides a reasonable experience on all devices at minimal cost to development time without the need to fear a new Android device with a new resolution you haven't factored in.

How to add Options Menu to Fragment in Android

If you want to add your menu custom

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setHasOptionsMenu(true);
}

@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
    inflater.inflate(R.menu.menu_custom, menu);
}

MySQL count occurrences greater than 2

To get a list of the words that appear more than once together with how often they occur, use a combination of GROUP BY and HAVING:

SELECT word, COUNT(*) AS cnt
FROM words
GROUP BY word
HAVING cnt > 1

To find the number of words in the above result set, use that as a subquery and count the rows in an outer query:

SELECT COUNT(*)
FROM
(
    SELECT NULL
    FROM words
    GROUP BY word
    HAVING COUNT(*) > 1
) T1

How to use systemctl in Ubuntu 14.04

Ubuntu 14 and lower does not have "systemctl" Source: https://docs.docker.com/install/linux/linux-postinstall/#configure-docker-to-start-on-boot

Configure Docker to start on boot:

Most current Linux distributions (RHEL, CentOS, Fedora, Ubuntu 16.04 and higher) use systemd to manage which services start when the system boots. Ubuntu 14.10 and below use upstart.

1) systemd (Ubuntu 16 and above):

$ sudo systemctl enable docker

To disable this behavior, use disable instead.

$ sudo systemctl disable docker

2) upstart (Ubuntu 14 and below):

Docker is automatically configured to start on boot using upstart. To disable this behavior, use the following command:

$ echo manual | sudo tee /etc/init/docker.override
chkconfig

$ sudo chkconfig docker on

Done.

MySQL - Meaning of "PRIMARY KEY", "UNIQUE KEY" and "KEY" when used together while creating a table

A key is just a normal index. A way over simplification is to think of it like a card catalog at a library. It points MySQL in the right direction.

A unique key is also used for improved searching speed, but it has the constraint that there can be no duplicated items (there are no two x and y where x is not y and x == y).

The manual explains it as follows:

A UNIQUE index creates a constraint such that all values in the index must be distinct. An error occurs if you try to add a new row with a key value that matches an existing row. This constraint does not apply to NULL values except for the BDB storage engine. For other engines, a UNIQUE index permits multiple NULL values for columns that can contain NULL. If you specify a prefix value for a column in a UNIQUE index, the column values must be unique within the prefix.

A primary key is a 'special' unique key. It basically is a unique key, except that it's used to identify something.

The manual explains how indexes are used in general: here.

In MSSQL, the concepts are similar. There are indexes, unique constraints and primary keys.

Untested, but I believe the MSSQL equivalent is:

CREATE TABLE tmp (
  id int NOT NULL PRIMARY KEY IDENTITY,
  uid varchar(255) NOT NULL CONSTRAINT uid_unique UNIQUE,
  name varchar(255) NOT NULL,
  tag int NOT NULL DEFAULT 0,
  description varchar(255),
);

CREATE INDEX idx_name ON tmp (name);
CREATE INDEX idx_tag ON tmp (tag);

Edit: the code above is tested to be correct; however, I suspect that there's a much better syntax for doing it. Been a while since I've used SQL server, and apparently I've forgotten quite a bit :).

Opening new window in HTML for target="_blank"

You can't influence neither type (tab/window) nor dimensions that way. You'll have to use JavaScript's window.open() for that.

SQL Server: Invalid Column Name

Could also happen if putting string in double quotes instead of single.

Git will not init/sync/update new submodules

I had the same problem today and figured out that because I typed git submodule init then I had those line in my .git/config:

[submodule]
   active = .

I removed that and typed:

git submodule update --init --remote

And everything was back to normal, my submodule updated in its subdirectory as usual.

Insert HTML from CSS

No. The only you can do is to add content (and not an element) using :before or :after pseudo-element.

More information: http://www.w3.org/TR/CSS2/generate.html#before-after-content

How do I download a binary file over HTTP?

The simplest way is the platform-specific solution:

 #!/usr/bin/env ruby
`wget http://somedomain.net/flv/sample/sample.flv`

Probably you are searching for:

require 'net/http'
# Must be somedomain.net instead of somedomain.net/, otherwise, it will throw exception.
Net::HTTP.start("somedomain.net") do |http|
    resp = http.get("/flv/sample/sample.flv")
    open("sample.flv", "wb") do |file|
        file.write(resp.body)
    end
end
puts "Done."

Edit: Changed. Thank You.

Edit2: The solution which saves part of a file while downloading:

# instead of http.get
f = open('sample.flv')
begin
    http.request_get('/sample.flv') do |resp|
        resp.read_body do |segment|
            f.write(segment)
        end
    end
ensure
    f.close()
end

How does MySQL process ORDER BY and LIMIT in a query?

Just as @James says, it will order all records, then get the first 20 rows.

As it is so, you are guaranteed to get the 20 first published articles, the newer ones will not be shown.

In your situation, I recommend that you add desc to order by publish_date, if you want the newest articles, then the newest article will be first.

If you need to keep the result in ascending order, and still only want the 10 newest articles you can ask mysql to sort your result two times.

This query below will sort the result descending and limit the result to 10 (that is the query inside the parenthesis). It will still be sorted in descending order, and we are not satisfied with that, so we ask mysql to sort it one more time. Now we have the newest result on the last row.

select t.article 
from 
    (select article, publish_date 
     from table1
     order by publish_date desc limit 10) t 

order by t.publish_date asc;

If you need all columns, it is done this way:

select t.* 
from 
    (select * 
     from table1  
     order by publish_date desc limit 10) t 

order by t.publish_date asc;

I use this technique when I manually write queries to examine the database for various things. I have not used it in a production environment, but now when I bench marked it, the extra sorting does not impact the performance.

Use of #pragma in C

This is a preprocessor directive that can be used to turn on or off certain features.

It is of two types #pragma startup, #pragma exit and #pragma warn.

#pragma startup allows us to specify functions called upon program startup.

#pragma exit allows us to specify functions called upon program exit.

#pragma warn tells the computer to suppress any warning or not.

Many other #pragma styles can be used to control the compiler.

How do I fix "Expected to return a value at the end of arrow function" warning?

The easiest way only if you don't need return something it'ts just return null

Finding height in Binary Search Tree

The height of a binary search tree is equal to number of layers - 1.

See the diagram at http://en.wikipedia.org/wiki/Binary_tree

Your recursion is good, so just subtract one at the root level.

Also note, you can clean up the function a bit by handling null nodes:

int findHeight(node) {
  if (node == null) return 0;
  return 1 + max(findHeight(node.left), findHeight(node.right));
}

concatenate two strings

You need to use the string concatenation operator +

String both = name + "-" + dest;

C++ unordered_map using a custom class type as the key

check the following link https://www.geeksforgeeks.org/how-to-create-an-unordered_map-of-user-defined-class-in-cpp/ for more details.

  • the custom class must implement the == operator
  • must create a hash function for the class (for primitive types like int and also types like string the hash function is predefined)

Delete all records in a table of MYSQL in phpMyAdmin

Go to the Sql tab run one of the below query:

delete from tableName;

Delete: will delete all rows from your table. Next insert will take next auto increment id.

or

truncate tableName;

Truncate: will also delete the rows from your table but it will start from new row with 1.

A detailed blog with example: http://sforsuresh.in/phpmyadmin-deleting-rows-mysql-table/

Auto height div with overflow and scroll when needed

You can do this assignment easily by using jquery. In this way, you can define number of row limitation. Furthermore, you can regular breakpoints height that want adding vertical scrolling. I must say that more than 3 rows get modify class and also height is 76px.

_x000D_
_x000D_
$(document).ready(function() {_x000D_
  var length = $(this).find('li').length;_x000D_
  if (length > 3) {_x000D_
    $(".parent").addClass('modify');_x000D_
  }_x000D_
})
_x000D_
/*for beauty*/_x000D_
_x000D_
ul {_x000D_
  margin: 0 auto;_x000D_
  width: 50%;_x000D_
  border: 1px solid #ccc;_x000D_
  padding: 3px;_x000D_
}_x000D_
_x000D_
ul li {_x000D_
  padding: 3px;_x000D_
  background: #ccc;_x000D_
  margin: 2px 0;_x000D_
  list-style: none;_x000D_
}_x000D_
_x000D_
/*main class*/_x000D_
_x000D_
.modify {_x000D_
  overflow-y: scroll;_x000D_
  height: 76px;_x000D_
}
_x000D_
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
_x000D_
<ul class="parent">_x000D_
  <li>item 1</li>_x000D_
  <li>item 2</li>_x000D_
  <li>item 3</li>_x000D_
  <li>item 4</li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

Find Number of CPUs and Cores per CPU using Command Prompt

In order to check the absence of physical sockets run:

wmic cpu get SocketDesignation

How to implement the Softmax function in Python

Based on all the responses and CS231n notes, allow me to summarise:

def softmax(x, axis):
    x -= np.max(x, axis=axis, keepdims=True)
    return np.exp(x) / np.exp(x).sum(axis=axis, keepdims=True)

Usage:

x = np.array([[1, 0, 2,-1],
              [2, 4, 6, 8], 
              [3, 2, 1, 0]])
softmax(x, axis=1).round(2)

Output:

array([[0.24, 0.09, 0.64, 0.03],
       [0.  , 0.02, 0.12, 0.86],
       [0.64, 0.24, 0.09, 0.03]])

WAMP 403 Forbidden message on Windows 7

I tried the configs above and only this worked for my WAMP Apache 2.4.2 config. For multiple root site without named domains in your Windows hosts file, use http://locahost:8080, http://localhost:8081, http://localhost:8082 and this configuration:

#ServerName localhost:80
ServerName localhost

Listen 8080
Listen 8081
Listen 8082
#..... 
<VirtualHost *:8080>
    DocumentRoot "c:\www"
    ServerName localhost
    <Directory "c:/www/">
        Options Indexes FollowSymLinks
        AllowOverride all
        Require local
    </Directory>
</VirtualHost>
<VirtualHost *:8081>
    DocumentRoot "C:\www\directory abc\svn_abc\trunk\httpdocs"
    ServerName localhost
    <Directory "C:\www\directory abc\svn_abc\trunk\httpdocs">
        Options Indexes FollowSymLinks
        AllowOverride all
        Require local
    </Directory>
</VirtualHost>
#<VirtualHost *:8082></VirtualHost>.......

Pandas join issue: columns overlap but no suffix specified

Mainly join is used exclusively to join based on the index,not on the attribute names,so change the attributes names in two different dataframes,then try to join,they will be joined,else this error is raised

Why does Node.js' fs.readFile() return a buffer instead of string?

The data variable contains a Buffer object. Convert it into ASCII encoding using the following syntax:

data.toString('ascii', 0, data.length)

Asynchronously:

fs.readFile('test.txt', 'utf8', function (error, data) {
    if (error) throw error;
    console.log(data.toString());
});

Reading string by char till end of line C/C++

A text file does not have \0 at the end of lines. It has \n. \n is a character, not a string, so it must be enclosed in single quotes

if (c == '\n')

How to automatically update your docker containers, if base-images are updated

Premise to my answer:

  1. Containers are run with tags.
  2. The same tag can be pointed to different image UUID as we please/ feel appropriate.
  3. Updates done to an image can be committed to a new image layer

Approach

  1. Build all the containers in the first place with a security-patch update script
  2. Build an automated process for the following
    • Run an existing image to new container with security patch script as the command
    • Commit changes to the image as
      • existing tag -> followed by restarting the containers one by one
      • new version tag -> replace few containers with new tag -> validate -> move all containers to new tag

Additionally, the base image can be upgraded/ the container with a complete new base image can be built at regular intervals, as the maintainer feels necessary

Advantages

  1. We are preserving the old version of the image while creating the new security patched image, hence we can rollback to previous running image if necessary
  2. We are preserving the docker cache, hence less network transfer (only the changed layer gets on the wire)
  3. The upgrade process can be validated in staging before moving to prod
  4. This can be a controlled process, hence the security patches only when necessary/ deemed important can be pushed.

Can I get the name of the current controller in the view?

Use controller.controller_name

In the Rails Guides, it says:

The params hash will always contain the :controller and :action keys, but you should use the methods controller_name and action_name instead to access these values

ActionController Parameters

So let's say you have a CSS class active , that should be inserted in any link whose page is currently open (maybe so that you can style differently) . If you have a static_pages controller with an about action, you can then highlight the link like so in your view:

<li>
  <a class='button <% if controller.controller_name == "static_pages" && controller.action_name == "about" %>active<%end%>' href="/about">
      About Us
  </a>
</li>

SQL Server: Importing database from .mdf?

If you do not have an LDF file then:

1) put the MDF in the C:\Program Files\Microsoft SQL Server\MSSQL13.SQLEXPRESS\MSSQL\DATA\

2) In ssms, go to Databases -> Attach and add the MDF file. It will not let you add it this way but it will tell you the database name contained within.

3) Make sure the user you are running ssms.exe as has acccess to this MDF file.

4) Now that you know the DbName, run

EXEC sp_attach_single_file_db @dbname = 'DbName', 
@physname = N'C:\Program Files\Microsoft SQL Server\MSSQL13.SQLEXPRESS\MSSQL\DATA\yourfile.mdf';

Reference: https://dba.stackexchange.com/questions/12089/attaching-mdf-without-ldf

Entity Framework The underlying provider failed on Open

Always check for Inner Exception if any. In my case Inner Exception turned out to be really helpful in figuring out the issue.

My site was working fine in Dev Environment. But after i deployed to production, it started giving out this exception, but the Inner Exception was saying that Login failed for the particular user.
So i figured out it was something to do with the connection itself. Hence tried logging in using SSMS and even that failed.

Eventually figured out that exception showed up for the simple reason that the SQL server had only Windows Authentication enabled and SQL Authentication was failing which was what i was using for Authentication.

In short, changing Authentication to Mixed(SQL and Windows), fixed the issue for me. :)

In jQuery how can I set "top,left" properties of an element with position values relative to the parent and not the document?

To set the position relative to the parent you need to set the position:relative of parent and position:absolute of the element

$("#mydiv").parent().css({position: 'relative'});
$("#mydiv").css({top: 200, left: 200, position:'absolute'});

This works because position: absolute; positions relatively to the closest positioned parent (i.e., the closest parent with any position property other than the default static).

Find an object in SQL Server (cross-database)

select db_name(), * From sysobjects where xtype in ('U', 'P') And name = 'OBJECT_name'

First column will display name of database where object is located at.

Setting a spinner onClickListener() in Android

First of all, a spinner does not support item click events. Calling this method will raise an exception.

You can use setOnItemSelectedListener:

Spinner s1;
s1 = (Spinner)findViewById(R.id.s1);
int selectionCurrent = s1.getSelectedItemPosition();

spinner.setOnItemSelectedListener(new OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {
            if (selectionCurrent != position){
                // Your code here
            }
            selectionCurrent= position;
        }
    }

    @Override
    public void onNothingSelected(AdapterView<?> parentView) {
        // Your code here
    }
});

Why is the time complexity of both DFS and BFS O( V + E )

Very simplified without much formality: every edge is considered exactly twice, and every node is processed exactly once, so the complexity has to be a constant multiple of the number of edges as well as the number of vertices.

Email address validation using ASP.NET MVC data type attributes

If you are using .NET Framework 4.5, the solution is to use EmailAddressAttribute which resides inside System.ComponentModel.DataAnnotations.

Your code should look similar to this:

[Display(Name = "Email address")]
[Required(ErrorMessage = "The email address is required")]
[EmailAddress(ErrorMessage = "Invalid Email Address")]
public string Email { get; set; }

How to display an unordered list in two columns?

Modern Browsers

leverage the css3 columns module to support what you are looking for.

http://www.w3schools.com/cssref/css3_pr_columns.asp

CSS:

ul {
  columns: 2;
  -webkit-columns: 2;
  -moz-columns: 2;
}

http://jsfiddle.net/HP85j/8/

Legacy Browsers

Unfortunately for IE support you will need a code solution that involves JavaScript and dom manipulation. This means that anytime the contents of the list changes you will need to perform the operation for reordering the list into columns and reprinting. The solution below uses jQuery for brevity.

http://jsfiddle.net/HP85j/19/

HTML:

<div>
    <ul class="columns" data-columns="2">
        <li>A</li>
        <li>B</li>
        <li>C</li>
        <li>D</li>
        <li>E</li>
        <li>F</li>
        <li>G</li>
    </ul>
</div>

JavaScript:

(function($){
    var initialContainer = $('.columns'),
        columnItems = $('.columns li'),
        columns = null,
        column = 1; // account for initial column
    function updateColumns(){
        column = 0;
        columnItems.each(function(idx, el){
            if (idx !== 0 && idx > (columnItems.length / columns.length) + (column * idx)){
                column += 1;
            }
            $(columns.get(column)).append(el);
        });
    }
    function setupColumns(){
        columnItems.detach();
        while (column++ < initialContainer.data('columns')){
            initialContainer.clone().insertBefore(initialContainer);
            column++;
        }
        columns = $('.columns');
    }

    $(function(){
        setupColumns();
        updateColumns();
    });
})(jQuery);

CSS:

.columns{
    float: left;
    position: relative;
    margin-right: 20px;
}

EDIT:

As pointed out below this will order the columns as follows:

A  E
B  F
C  G
D

while the OP asked for a variant matching the following:

A  B
C  D
E  F
G

To accomplish the variant you simply change the code to the following:

function updateColumns(){
    column = 0;
    columnItems.each(function(idx, el){
        if (column > columns.length){
            column = 0;
        }
        $(columns.get(column)).append(el);
        column += 1;
    });
}

How to choose an AWS profile when using boto3 to connect to CloudFront

Just add profile to session configuration before client call. boto3.session.Session(profile_name='YOUR_PROFILE_NAME').client('cloudwatch')

The maximum value for an int type in Go

I would use math package for getting the maximal value and minimal value :

func printMinMaxValue() {
    // integer max
    fmt.Printf("max int64 = %+v\n", math.MaxInt64)
    fmt.Printf("max int32 = %+v\n", math.MaxInt32)
    fmt.Printf("max int16 = %+v\n", math.MaxInt16)

    // integer min
    fmt.Printf("min int64 = %+v\n", math.MinInt64)
    fmt.Printf("min int32 = %+v\n", math.MinInt32)

    fmt.Printf("max flloat64= %+v\n", math.MaxFloat64)
    fmt.Printf("max float32= %+v\n", math.MaxFloat32)

    // etc you can see more int the `math`package
}

Ouput :

max int64 = 9223372036854775807
max int32 = 2147483647
max int16 = 32767
min int64 = -9223372036854775808
min int32 = -2147483648
max flloat64= 1.7976931348623157e+308
max float32= 3.4028234663852886e+38

Dynamically updating plot in matplotlib

Here is a way which allows to remove points after a certain number of points plotted:

import matplotlib.pyplot as plt
# generate axes object
ax = plt.axes()

# set limits
plt.xlim(0,10) 
plt.ylim(0,10)

for i in range(10):        
     # add something to axes    
     ax.scatter([i], [i]) 
     ax.plot([i], [i+1], 'rx')

     # draw the plot
     plt.draw() 
     plt.pause(0.01) #is necessary for the plot to update for some reason

     # start removing points if you don't want all shown
     if i>2:
         ax.lines[0].remove()
         ax.collections[0].remove()

PHP salt and hash SHA256 for login password

You couldn't login because you did't get proper solt text at login time. There are two options, first is define static salt, second is if you want create dynamic salt than you have to store the salt somewhere (means in database) with associate with user. Than you concatenate user solt+password_hash string now with this you fire query with username in your database table.