Programs & Examples On #Sqlmail

Failed to install android-sdk: "java.lang.NoClassDefFoundError: javax/xml/bind/annotation/XmlSchema"

TLDR; Try setting JAVA_HOME worked fine for me on OSX

export JAVA_HOME=/Library/Java/JavaVirtualMachines/adoptopenjdk-8.jdk/Contents/Home

To install the JDKs 8 ( LTS ) from AdoptOpenJDK:

# brew tap adoptopenjdk/openjdk

brew cask install adoptopenjdk/openjdk/adoptopenjdk8

How do I efficiently iterate over each entry in a Java Map?

Map<String, String> map = ...
for (Map.Entry<String, String> entry : map.entrySet()) {
    System.out.println(entry.getKey() + "/" + entry.getValue());
}

How to terminate a window in tmux?

ctrl + d kills a window in linux terminal, also works in tmux.

This is kind of a approach.

For Restful API, can GET method use json data?

To answer your question, yes you may pass JSON in the URI as part of a GET request (provided you URL-encode). However, considering your reason for doing this is due to the length of the URI, using JSON will be self-defeating (introducing more characters than required).

I suggest you send your parameters in body of a POST request, either in regular CGI style (param1=val1&param2=val2) or JSON (parsed by your API upon receipt)

Convert pandas data frame to series

It's not smart enough to realize it's still a "vector" in math terms.

Say rather that it's smart enough to recognize a difference in dimensionality. :-)

I think the simplest thing you can do is select that row positionally using iloc, which gives you a Series with the columns as the new index and the values as the values:

>>> df = pd.DataFrame([list(range(5))], columns=["a{}".format(i) for i in range(5)])
>>> df
   a0  a1  a2  a3  a4
0   0   1   2   3   4
>>> df.iloc[0]
a0    0
a1    1
a2    2
a3    3
a4    4
Name: 0, dtype: int64
>>> type(_)
<class 'pandas.core.series.Series'>

How to center icon and text in a android button with width set to "fill parent"

This is my solution I wrote 3 years ago. Button has text and left icon and is in frame that is actual button here and can be stretched by fill_parent. I cannot test it again but it was working back then. Probably Button don't have to be used and can be replaced by TextView but I will not test it right now and it doesn't change functionality too much here.

<FrameLayout
    android:id="@+id/login_button_login"
    android:background="@drawable/apptheme_btn_default_holo_dark"
    android:layout_width="fill_parent"
    android:layout_gravity="center"
    android:layout_height="40dp">
    <Button
        android:clickable="false"
        android:drawablePadding="15dp"
        android:layout_gravity="center"
        style="@style/WhiteText.Small.Bold"
        android:drawableLeft="@drawable/lock"
        android:background="@color/transparent"
        android:text="LOGIN" />
</FrameLayout>

ActiveXObject is not defined and can't find variable: ActiveXObject

ActiveXObject is non-standard and only supported by Internet Explorer on Windows.

There is no native cross browser way to write to the file system without using plugins, even the draft File API gives read only access.

If you want to work cross platform, then you need to look at such things as signed Java applets (keeping in mind that that will only work on platforms for which the Java runtime is available).

How to get substring in C

If the task is only copying 4 characters, try for loops. If it's going to be more advanced and you're asking for a function, try strncpy. http://www.cplusplus.com/reference/clibrary/cstring/strncpy/

strncpy(sub1, baseString, 4);
strncpy(sub1, baseString+4, 4);
strncpy(sub1, baseString+8, 4);

or

for(int i=0; i<4; i++)
    sub1[i] = baseString[i];
sub1[4] = 0;
for(int i=0; i<4; i++)
    sub2[i] = baseString[i+4];
sub2[4] = 0;
for(int i=0; i<4; i++)
    sub3[i] = baseString[i+8];
sub3[4] = 0;

Prefer strncpy if possible.

Convert Go map to json

Since this question was asked/last answered, support for non string key types for maps for json Marshal/UnMarshal has been added through the use of TextMarshaler and TextUnmarshaler interfaces here. You could just implement these interfaces for your key types and then json.Marshal would work as expected.

package main

import (
    "encoding/json"
    "fmt"
    "strconv"
)

// Num wraps the int value so that we can implement the TextMarshaler and TextUnmarshaler 
type Num int

func (n *Num) UnmarshalText(text []byte) error {
    i, err := strconv.Atoi(string(text))
    if err != nil {
        return err
    }
    *n = Num(i)
    return nil
}

func (n Num) MarshalText() (text []byte, err error) {
    return []byte(strconv.Itoa(int(n))), nil
}

type Foo struct {
    Number Num    `json:"number"`
    Title  string `json:"title"`
}

func main() {
    datas := make(map[Num]Foo)

    for i := 0; i < 10; i++ {
        datas[Num(i)] = Foo{Number: 1, Title: "test"}
    }

    jsonString, err := json.Marshal(datas)
    if err != nil {
        panic(err)
    }

    fmt.Println(datas)
    fmt.Println(jsonString)

    m := make(map[Num]Foo)
    err = json.Unmarshal(jsonString, &m)
    if err != nil {
        panic(err)
    }

    fmt.Println(m)
}

Output:

map[1:{1 test} 2:{1 test} 4:{1 test} 7:{1 test} 8:{1 test} 9:{1 test} 0:{1 test} 3:{1 test} 5:{1 test} 6:{1 test}]
[123 34 48 34 58 123 34 110 117 109 98 101 114 34 58 34 49 34 44 34 116 105 116 108 101 34 58 34 116 101 115 116 34 125 44 34 49 34 58 123 34 110 117 109 98 101 114 34 58 34 49 34 44 34 116 105 116 108 101 34 58 34 116 101 115 116 34 125 44 34 50 34 58 123 34 110 117 109 98 101 114 34 58 34 49 34 44 34 116 105 116 108 101 34 58 34 116 101 115 116 34 125 44 34 51 34 58 123 34 110 117 109 98 101 114 34 58 34 49 34 44 34 116 105 116 108 101 34 58 34 116 101 115 116 34 125 44 34 52 34 58 123 34 110 117 109 98 101 114 34 58 34 49 34 44 34 116 105 116 108 101 34 58 34 116 101 115 116 34 125 44 34 53 34 58 123 34 110 117 109 98 101 114 34 58 34 49 34 44 34 116 105 116 108 101 34 58 34 116 101 115 116 34 125 44 34 54 34 58 123 34 110 117 109 98 101 114 34 58 34 49 34 44 34 116 105 116 108 101 34 58 34 116 101 115 116 34 125 44 34 55 34 58 123 34 110 117 109 98 101 114 34 58 34 49 34 44 34 116 105 116 108 101 34 58 34 116 101 115 116 34 125 44 34 56 34 58 123 34 110 117 109 98 101 114 34 58 34 49 34 44 34 116 105 116 108 101 34 58 34 116 101 115 116 34 125 44 34 57 34 58 123 34 110 117 109 98 101 114 34 58 34 49 34 44 34 116 105 116 108 101 34 58 34 116 101 115 116 34 125 125]
map[4:{1 test} 5:{1 test} 6:{1 test} 7:{1 test} 0:{1 test} 2:{1 test} 3:{1 test} 1:{1 test} 8:{1 test} 9:{1 test}]

mysqli::query(): Couldn't fetch mysqli

Probably somewhere you have DBconnection->close(); and then some queries try to execute .


Hint: It's sometimes mistake to insert ...->close(); in __destruct() (because __destruct is event, after which there will be a need for execution of queries)

Writing BMP image in pure c/c++ without other libraries

C++ answer, flexible API, assumes little-endian system to code-golf it a bit. Note this uses the bmp native y-axis (0 at the bottom).

#include <vector>
#include <fstream>

struct image
{   
    image(int width, int height)
    :   w(width), h(height), rgb(w * h * 3)
    {}
    uint8_t & r(int x, int y) { return rgb[(x + y*w)*3 + 2]; }
    uint8_t & g(int x, int y) { return rgb[(x + y*w)*3 + 1]; }
    uint8_t & b(int x, int y) { return rgb[(x + y*w)*3 + 0]; }

    int w, h;
    std::vector<uint8_t> rgb;
};

template<class Stream>
Stream & operator<<(Stream & out, image const& img)
{   
    uint32_t w = img.w, h = img.h;
    uint32_t pad = w * -3 & 3;
    uint32_t total = 54 + 3*w*h + pad*h;
    uint32_t head[13] = {total, 0, 54, 40, w, h, (24<<16)|1};
    char const* rgb = (char const*)img.rgb.data();

    out.write("BM", 2);
    out.write((char*)head, 52);
    for(uint32_t i=0 ; i<h ; i++)
    {   out.write(rgb + (3 * w * i), 3 * w);
        out.write((char*)&pad, pad);
    }
    return out;
}

int main()
{
    image img(100, 100);
    for(int x=0 ; x<100 ; x++)
    {   for(int y=0 ; y<100 ; y++)
        {   img.r(x,y) = x;
            img.g(x,y) = y;
            img.b(x,y) = 100-x;
        }
    }
    std::ofstream("/tmp/out.bmp") << img;
}

C#: How do you edit items and subitems in a listview?

I use a hidden textbox to edit all the listview items/subitems. The only problem is that the textbox needs to disappear as soon as any event takes place outside the textbox and the listview doesn't trigger the scroll event so if you scroll the listview the textbox will still be visible. To bypass this problem I created the Scroll event with this overrided listview.

Here is my code, I constantly reuse it so it might be help for someone:

ListViewItem.ListViewSubItem SelectedLSI;
private void listView2_MouseUp(object sender, MouseEventArgs e)
{
    ListViewHitTestInfo i = listView2.HitTest(e.X, e.Y);
    SelectedLSI = i.SubItem;
    if (SelectedLSI == null)
        return;

    int border = 0;
    switch (listView2.BorderStyle)
    {
        case BorderStyle.FixedSingle:
            border = 1;
            break;
        case BorderStyle.Fixed3D:
            border = 2;
            break;
    }

    int CellWidth = SelectedLSI.Bounds.Width;
    int CellHeight = SelectedLSI.Bounds.Height;
    int CellLeft = border + listView2.Left + i.SubItem.Bounds.Left;
    int CellTop =listView2.Top + i.SubItem.Bounds.Top;
    // First Column
    if (i.SubItem == i.Item.SubItems[0])
        CellWidth = listView2.Columns[0].Width;

    TxtEdit.Location = new Point(CellLeft, CellTop);
    TxtEdit.Size = new Size(CellWidth, CellHeight);
    TxtEdit.Visible = true;
    TxtEdit.BringToFront();
    TxtEdit.Text = i.SubItem.Text;
    TxtEdit.Select();
    TxtEdit.SelectAll();
}
private void listView2_MouseDown(object sender, MouseEventArgs e)
{
    HideTextEditor();
}
private void listView2_Scroll(object sender, EventArgs e)
{
    HideTextEditor();
}
private void TxtEdit_Leave(object sender, EventArgs e)
{
    HideTextEditor();
}
private void TxtEdit_KeyUp(object sender, KeyEventArgs e)
{
    if (e.KeyCode == Keys.Enter || e.KeyCode == Keys.Return)
        HideTextEditor();
}
private void HideTextEditor()
{
    TxtEdit.Visible = false;
    if (SelectedLSI != null)
        SelectedLSI.Text = TxtEdit.Text;
    SelectedLSI = null;
    TxtEdit.Text = "";
}

Swift Open Link in Safari

In Swift 2.0:

UIApplication.sharedApplication().openURL(NSURL(string: "http://stackoverflow.com")!)

How to delete object?

It sounds like you need to create a wrapper around an instance you can invalidate:

public class Ref<T> where T : class
{
    private T instance;
    public Ref(T instance)
    {
        this.instance = instance;
    }

    public static implicit operator Ref<T>(T inner)
    {
        return new Ref<T>(inner);
    }

    public void Delete()
    {
        this.instance = null;
    }

    public T Instance
    {
        get { return this.instance; }
    }
}

and you can use it like:

Ref<Car> carRef = new Car();
carRef.Delete();
var car = carRef.Instance;     //car is null

Be aware however that if any code saves the inner value in a variable, this will not be invalidated by calling Delete.

Json.net serialize/deserialize derived types?

If you are storing the type in your text (as you should be in this scenario), you can use the JsonSerializerSettings.

See: how to deserialize JSON into IEnumerable<BaseType> with Newtonsoft JSON.NET

Be careful, though. Using anything other than TypeNameHandling = TypeNameHandling.None could open yourself up to a security vulnerability.

How to solve 'Redirect has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header'?

Do specify @CrossOrigin(origins = "http://localhost:8081") in Controller class.

java.sql.SQLException: Incorrect string value: '\xF0\x9F\x91\xBD\xF0\x9F...'

All in all, to save symbols that require 4 bytes you need to update characher-set and collation for utf8mb4:

  1. database table/column: alter table <some_table> convert to character set utf8mb4 collate utf8mb4_unicode_ci
  2. database server connection (see)

On my development enviromnt for #2 I prefer to set parameters on command line when starting the server: mysqld --character-set-server=utf8mb4 --collation-server=utf8mb4_unicode_ci


btw, pay attention to Connector/J behavior with SET NAMES 'utf8mb4':

Do not issue the query set names with Connector/J, as the driver will not detect that the character set has changed, and will continue to use the character set detected during the initial connection setup.

And avoid setting characterEncoding parameter in connection url as it will override configured server encoding:

To override the automatically detected encoding on the client side, use the characterEncoding property in the URL used to connect to the server.

How can I decrypt a password hash in PHP?

Use the password_verify() function

if (password_vertify($inputpassword, $row['password'])) {
  print "Logged in";
else {
    print "Password Incorrect";
}

Controller 'ngModel', required by directive '...', can't be found

You can also remove the line

  require: 'ngModel',

if you don't need ngModel in this directive. Removing ngModel will allow you to make a directive without thatngModel error.

python ValueError: invalid literal for float()

I had a similar issue reading the serial output from a digital scale. I was reading [3:12] out of a 18 characters long output string.

In my case sometimes there is a null character "\x00" (NUL) which magically appears in the scale's reply string and is not printed.

I was getting the error:

> '     0.00'
> 3 0 fast loop, delta =  10.0 weight =  0.0 
> '     0.00'
> 1 800 fast loop, delta = 10.0 weight =  0.0 
> '     0.00'
> 6 0 fast loop, delta =  10.0 weight =  0.0
> '     0\x00.0' 
> Traceback (most recent call last):
>   File "measure_weight_speed.py", line 172, in start
>     valueScale = float(answer_string) 
>     ValueError: invalid literal for float(): 0

After some research I wrote few lines of code that work in my case.

replyScale = scale_port.read(18)
answer = replyScale[3:12]
answer_decode = answer.replace("\x00", "")
answer_strip = str(answer_decode.strip())
print(repr(answer_strip))
valueScale = float(answer_strip)

The answers in these posts helped:

  1. How to get rid of \x00 in my array of bytes?
  2. Invalid literal for float(): 0.000001, how to fix error?

Convert PDF to clean SVG?

I found that xfig did an excellent job:

pstoedit -f fig foo.pdf foo.fig
xfig foo.fig

export to svg

It did much better job than inkscape. Actually it was probably pdtoedit that did it.

How to get file creation & modification date/times in Python?

os.stat does include the creation time. There's just no definition of st_anything for the element of os.stat() that contains the time.

So try this:

os.stat('feedparser.py')[8]

Compare that with your create date on the file in ls -lah

They should be the same.

#1214 - The used table type doesn't support FULLTEXT indexes

From official reference

Full-text indexes can be used only with MyISAM tables. (In MySQL 5.6 and up, they can also be used with InnoDB tables.) Full-text indexes can be created only for CHAR, VARCHAR, or TEXT columns.

https://dev.mysql.com/doc/refman/5.5/en/fulltext-search.html

InnoDB with MySQL 5.5 does not support Full-text indexes.

Make Axios send cookies in its requests automatically

I had the same problem and fixed it by using the withCredentials property.

XMLHttpRequest from a different domain cannot set cookie values for their own domain unless withCredentials is set to true before making the request.

axios.get('some api url', {withCredentials: true});

Error creating bean with name 'entityManagerFactory' defined in class path resource : Invocation of init method failed

For me it was the name of the database on application.properties. When I provided the correct name it worked ok.

Failed to load resource: net::ERR_INSECURE_RESPONSE

This problem is because of your https that means SSL certification. Try on Localhost.

How to find out when a particular table was created in Oracle?

You copy and paste the following code. It will display all the tables with Name and Created Date

SELECT object_name,created FROM user_objects
WHERE object_name LIKE  '%table_name%'
AND object_type = 'TABLE'; 

Note: Replace '%table_name%' with the table name you are looking for.

MySQL fails on: mysql "ERROR 1524 (HY000): Plugin 'auth_socket' is not loaded"

For Ubuntu 18.04 and mysql 5.7

  • step 1: sudo mkdir /var/run/mysqld;

    step 2: sudo chown mysql /var/run/mysqld

    step 3: sudo mysqld_safe --skip-grant-tables & quit (use quit if its stuck )

login to mysql without password

  • step 4: sudo mysql --user=root mysql

    step 5: SELECT user,authentication_string,plugin,host FROM mysql.user;

    step 6: ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'root'

now login with

  • mysql -u root -p <root>

How to insert a new key value pair in array in php?

Try this:

foreach($array as $k => $obj) { 
    $obj->{'newKey'} = "value"; 
}

How to call a parent method from child class in javascript?

While you can call the parent method by the prototype of the parent, you will need to pass the current child instance for using call, apply, or bind method. The bind method will create a new function so I doesn't recommend that if you care for performance except it only called once.

As an alternative you can replace the child method and put the parent method on the instance while calling the original child method.

_x000D_
_x000D_
function proxy(context, parent){
  var proto = parent.prototype;
  var list = Object.getOwnPropertyNames(proto);
  
  for(var i=0; i < list.length; i++){
    var key = list[i];

    // Create only when child have similar method name
    if(context[key] !== proto[key]){
      let currentMethod = context[key];
      let parentMethod = proto[key];
      
      context[key] = function(){
        context.super = parentMethod;
        return currentMethod.apply(context, arguments);
      }
    }
  }
}

// ========= The usage would be like this ==========

class Parent {
  first = "Home";

  constructor(){
    console.log('Parent created');
  }

  add(arg){
    return this.first + ", Parent "+arg;
  }
}

class Child extends Parent{
  constructor(b){
    super();
    proxy(this, Parent);
    console.log('Child created');
  }

  // Comment this to call method from parent only
  add(arg){
    return super.add(arg) + ", Child "+arg;
  }
}

var family = new Child();
console.log(family.add('B'));
_x000D_
_x000D_
_x000D_

How can a add a row to a data frame in R?

Like @Khashaa and @Richard Scriven point out in comments, you have to set consistent column names for all the data frames you want to append.

Hence, you need to explicitly declare the columns names for the second data frame, de, then use rbind(). You only set column names for the first data frame, df:

df<-data.frame("hi","bye")
names(df)<-c("hello","goodbye")

de<-data.frame("hola","ciao")
names(de)<-c("hello","goodbye")

newdf <- rbind(df, de)

100% width background image with an 'auto' height

Add the css:

   html,body{
        height:100%;
        }
    .bg-img {
        background: url(image.jpg) no-repeat center top; 
        background-size: cover; 
        height:100%;     
    }

And html is:

<div class="bg-mg"></div>

CSS: stretching background image to 100% width and height of screen?

How do I specify the exit code of a console application in .NET?

My 2 cents:

You can find the system error codes here: https://msdn.microsoft.com/en-us/library/windows/desktop/ms681382(v=vs.85).aspx

You will find the typical codes like 2 for "file not found" or 5 for "access denied".

And when you stumble on an unknown code, you can use this command to find out what it means:

net helpmsg decimal_code

e.g.

net helpmsg 1

returns

Incorrect function

How to set specific window (frame) size in java swing?

Well, you are using both frame.setSize() and frame.pack().

You should use one of them at one time.

Using setSize() you can give the size of frame you want but if you use pack(), it will automatically change the size of the frames according to the size of components in it. It will not consider the size you have mentioned earlier.

Try removing frame.pack() from your code or putting it before setting size and then run it.

How do I get the path of the Python script I am running in?

The accepted solution for this will not work if you are planning to compile your scripts using py2exe. If you're planning to do so, this is the functional equivalent:

os.path.dirname(sys.argv[0])

Py2exe does not provide an __file__ variable. For reference: http://www.py2exe.org/index.cgi/Py2exeEnvironment

Defining TypeScript callback type

If you want a generic function you can use the following. Although it doesn't seem to be documented anywhere.

class CallbackTest {
  myCallback: Function;
}   

IIS: Idle Timeout vs Recycle

Idle Timeout is if no action has been asked from your web app, it the process will drop and release everything from memory

Recycle is a forced action on the application where your processed is closed and started again, for memory leaking purposes and system health

The negative impact of both is usually the use of your Session and Application state is lost if you mess with Recycle to a faster time.(logged in users etc will be logged out, if they where about to "check out" all would have been lost" that's why recycle is at such a large time out value, idle timeout doesn't matter because nobody is logged in anyway and figure 20 minutes an no action they are not still "shopping"

The positive would be get rid of the idle time out as your website will respond faster on its "first" response if its not a highly active site where a user would have to wait for it to load if you have 1 user every 20 minutes lets say. So a website that get his less then 1 time in 20 minutes actually you would want to increase this value as the website has to load up again from scratch for each user. but if you set this to 0 over a long time, any memory leaks in code could over a certain amount of time, entirely take over the server.

Use placeholders in yaml

I suppose https://get-ytt.io/ would be an acceptable solution to your problem

What's the Android ADB shell "dumpsys" tool and what are its benefits?

According to official Android information about dumpsys:

The dumpsys tool runs on the device and provides information about the status of system services.

To get a list of available services use

adb shell dumpsys -l

How to get the range of occupied cells in excel sheet

I had a very similar issue as you had. What actually worked is this:

iTotalColumns = xlWorkSheet.UsedRange.Columns.Count;
iTotalRows = xlWorkSheet.UsedRange.Rows.Count;

//These two lines do the magic.
xlWorkSheet.Columns.ClearFormats();
xlWorkSheet.Rows.ClearFormats();

iTotalColumns = xlWorkSheet.UsedRange.Columns.Count;
iTotalRows = xlWorkSheet.UsedRange.Rows.Count;

IMHO what happens is that when you delete data from Excel, it keeps on thinking that there is data in those cells, though they are blank. When I cleared the formats, it removes the blank cells and hence returns actual counts.

How to loop through a collection that supports IEnumerable?

foreach (var element in instanceOfAClassThatImplelemntIEnumerable)
{

}

How do I convert a byte array to Base64 in Java?

Use:

byte[] data = Base64.encode(base64str);

Encoding converts to Base64

You would need to reference commons codec from your project in order for that code to work.

For java8:

import java.util.Base64

I forgot the password I entered during postgres installation

The pg_hba.conf (C:\Program Files\PostgreSQL\9.3\data) file has changed since these answers were given. What worked for me, in Windows, is to open the file and change the METHOD from md5 to trust:

# TYPE  DATABASE        USER            ADDRESS                 METHOD

# IPv4 local connections:
host    all             all             127.0.0.1/32            trust
# IPv6 local connections:
host    all             all             ::1/128                 trust

Then, using pgAdmin III, I logged in using no password and changed user postgres' password by going to File -> Change Password

Access-control-allow-origin with multiple domains

You can add this code to your asp.net webapi project

in file Global.asax

    protected void Application_BeginRequest()
{
    string origin = Request.Headers.Get("Origin");
    if (Request.HttpMethod == "OPTIONS")
    {
        Response.AddHeader("Access-Control-Allow-Origin", origin);
        Response.AddHeader("Access-Control-Allow-Headers", "*");
        Response.AddHeader("Access-Control-Allow-Methods", "GET,POST,PUT,OPTIONS,DELETE");
        Response.StatusCode = 200;
        Response.End();
    }
    else
    {
        Response.AddHeader("Access-Control-Allow-Origin", origin);
        Response.AddHeader("Access-Control-Allow-Headers", "*");
        Response.AddHeader("Access-Control-Allow-Methods", "GET,POST,PUT,OPTIONS,DELETE");
    }
}

Map and Reduce in .NET

Since I never can remember that LINQ calls it Where, Select and Aggregate instead of Filter, Map and Reduce so I created a few extension methods you can use:

IEnumerable<string> myStrings = new List<string>() { "1", "2", "3", "4", "5" };
IEnumerable<int> convertedToInts = myStrings.Map(s => int.Parse(s));
IEnumerable<int> filteredInts = convertedToInts.Filter(i => i <= 3); // Keep 1,2,3
int sumOfAllInts = filteredInts.Reduce((sum, i) => sum + i); // Sum up all ints
Assert.Equal(6, sumOfAllInts); // 1+2+3 is 6

Here are the 3 methods (from https://github.com/cs-util-com/cscore/blob/master/CsCore/PlainNetClassLib/src/Plugins/CsCore/com/csutil/collections/IEnumerableExtensions.cs ):

public static IEnumerable<R> Map<T, R>(this IEnumerable<T> self, Func<T, R> selector) {
    return self.Select(selector);
}

public static T Reduce<T>(this IEnumerable<T> self, Func<T, T, T> func) {
    return self.Aggregate(func);
}

public static IEnumerable<T> Filter<T>(this IEnumerable<T> self, Func<T, bool> predicate) {
    return self.Where(predicate);
}

Some more details from https://github.com/cs-util-com/cscore#ienumerable-extensions :

enter image description here

AngularJs - ng-model in a SELECT

try the following code :

In your controller :

 function myCtrl ($scope) {
      $scope.units = [
         {'id': 10, 'label': 'test1'},
         {'id': 27, 'label': 'test2'},
         {'id': 39, 'label': 'test3'},
      ];

   $scope.data= $scope.units[0]; // Set by default the value "test1"
 };

In your page :

 <select ng-model="data" ng-options="opt as opt.label for opt in units ">
                </select>

Working Fiddle

How are zlib, gzip and zip related? What do they have in common and how are they different?

Short form:

.zip is an archive format using, usually, the Deflate compression method. The .gz gzip format is for single files, also using the Deflate compression method. Often gzip is used in combination with tar to make a compressed archive format, .tar.gz. The zlib library provides Deflate compression and decompression code for use by zip, gzip, png (which uses the zlib wrapper on deflate data), and many other applications.

Long form:

The ZIP format was developed by Phil Katz as an open format with an open specification, where his implementation, PKZIP, was shareware. It is an archive format that stores files and their directory structure, where each file is individually compressed. The file type is .zip. The files, as well as the directory structure, can optionally be encrypted.

The ZIP format supports several compression methods:

    0 - The file is stored (no compression)
    1 - The file is Shrunk
    2 - The file is Reduced with compression factor 1
    3 - The file is Reduced with compression factor 2
    4 - The file is Reduced with compression factor 3
    5 - The file is Reduced with compression factor 4
    6 - The file is Imploded
    7 - Reserved for Tokenizing compression algorithm
    8 - The file is Deflated
    9 - Enhanced Deflating using Deflate64(tm)
   10 - PKWARE Data Compression Library Imploding (old IBM TERSE)
   11 - Reserved by PKWARE
   12 - File is compressed using BZIP2 algorithm
   13 - Reserved by PKWARE
   14 - LZMA
   15 - Reserved by PKWARE
   16 - IBM z/OS CMPSC Compression
   17 - Reserved by PKWARE
   18 - File is compressed using IBM TERSE (new)
   19 - IBM LZ77 z Architecture 
   20 - deprecated (use method 93 for zstd)
   93 - Zstandard (zstd) Compression 
   94 - MP3 Compression 
   95 - XZ Compression 
   96 - JPEG variant
   97 - WavPack compressed data
   98 - PPMd version I, Rev 1
   99 - AE-x encryption marker (see APPENDIX E)

Methods 1 to 7 are historical and are not in use. Methods 9 through 98 are relatively recent additions and are in varying, small amounts of use. The only method in truly widespread use in the ZIP format is method 8, Deflate, and to some smaller extent method 0, which is no compression at all. Virtually every .zip file that you will come across in the wild will use exclusively methods 8 and 0, likely just method 8. (Method 8 also has a means to effectively store the data with no compression and relatively little expansion, and Method 0 cannot be streamed whereas Method 8 can be.)

The ISO/IEC 21320-1:2015 standard for file containers is a restricted zip format, such as used in Java archive files (.jar), Office Open XML files (Microsoft Office .docx, .xlsx, .pptx), Office Document Format files (.odt, .ods, .odp), and EPUB files (.epub). That standard limits the compression methods to 0 and 8, as well as other constraints such as no encryption or signatures.

Around 1990, the Info-ZIP group wrote portable, free, open-source implementations of zip and unzip utilities, supporting compression with the Deflate format, and decompression of that and the earlier formats. This greatly expanded the use of the .zip format.

In the early '90s, the gzip format was developed as a replacement for the Unix compress utility, derived from the Deflate code in the Info-ZIP utilities. Unix compress was designed to compress a single file or stream, appending a .Z to the file name. compress uses the LZW compression algorithm, which at the time was under patent and its free use was in dispute by the patent holders. Though some specific implementations of Deflate were patented by Phil Katz, the format was not, and so it was possible to write a Deflate implementation that did not infringe on any patents. That implementation has not been so challenged in the last 20+ years. The Unix gzip utility was intended as a drop-in replacement for compress, and in fact is able to decompress compress-compressed data (assuming that you were able to parse that sentence). gzip appends a .gz to the file name. gzip uses the Deflate compressed data format, which compresses quite a bit better than Unix compress, has very fast decompression, and adds a CRC-32 as an integrity check for the data. The header format also permits the storage of more information than the compress format allowed, such as the original file name and the file modification time.

Though compress only compresses a single file, it was common to use the tar utility to create an archive of files, their attributes, and their directory structure into a single .tar file, and to then compress it with compress to make a .tar.Z file. In fact, the tar utility had and still has an option to do the compression at the same time, instead of having to pipe the output of tar to compress. This all carried forward to the gzip format, and tar has an option to compress directly to the .tar.gz format. The tar.gz format compresses better than the .zip approach, since the compression of a .tar can take advantage of redundancy across files, especially many small files. .tar.gz is the most common archive format in use on Unix due to its very high portability, but there are more effective compression methods in use as well, so you will often see .tar.bz2 and .tar.xz archives.

Unlike .tar, .zip has a central directory at the end, which provides a list of the contents. That and the separate compression provides random access to the individual entries in a .zip file. A .tar file would have to be decompressed and scanned from start to end in order to build a directory, which is how a .tar file is listed.

Shortly after the introduction of gzip, around the mid-1990s, the same patent dispute called into question the free use of the .gif image format, very widely used on bulletin boards and the World Wide Web (a new thing at the time). So a small group created the PNG losslessly compressed image format, with file type .png, to replace .gif. That format also uses the Deflate format for compression, which is applied after filters on the image data expose more of the redundancy. In order to promote widespread usage of the PNG format, two free code libraries were created. libpng and zlib. libpng handled all of the features of the PNG format, and zlib provided the compression and decompression code for use by libpng, as well as for other applications. zlib was adapted from the gzip code.

All of the mentioned patents have since expired.

The zlib library supports Deflate compression and decompression, and three kinds of wrapping around the deflate streams. Those are: no wrapping at all ("raw" deflate), zlib wrapping, which is used in the PNG format data blocks, and gzip wrapping, to provide gzip routines for the programmer. The main difference between zlib and gzip wrapping is that the zlib wrapping is more compact, six bytes vs. a minimum of 18 bytes for gzip, and the integrity check, Adler-32, runs faster than the CRC-32 that gzip uses. Raw deflate is used by programs that read and write the .zip format, which is another format that wraps around deflate compressed data.

zlib is now in wide use for data transmission and storage. For example, most HTTP transactions by servers and browsers compress and decompress the data using zlib, specifically HTTP header Content-Encoding: deflate means deflate compression method wrapped inside the zlib data format.

Different implementations of deflate can result in different compressed output for the same input data, as evidenced by the existence of selectable compression levels that allow trading off compression effectiveness for CPU time. zlib and PKZIP are not the only implementations of deflate compression and decompression. Both the 7-Zip archiving utility and Google's zopfli library have the ability to use much more CPU time than zlib in order to squeeze out the last few bits possible when using the deflate format, reducing compressed sizes by a few percent as compared to zlib's highest compression level. The pigz utility, a parallel implementation of gzip, includes the option to use zlib (compression levels 1-9) or zopfli (compression level 11), and somewhat mitigates the time impact of using zopfli by splitting the compression of large files over multiple processors and cores.

SVN Commit failed, access forbidden

Actually, I had this problem same as you. You can get the "Forbidden" error if your commit includes different directories ; Like external items.

And i solved in one step. Just commit external items in another case.

Additionally, I advise you to read articles on External Items in Subversion and VisualSVN Server:

VisualSVN Team's article about Daily Use Guide External Items. It explains the principles of External Items in SVN.

https://tortoisesvn.net/docs/release/TortoiseSVN_en/tsvn-dug-externals.html

Can I access constants in settings.py from templates in Django?

I improved chrisdew's answer (to create your own tag) a little bit.

First, create the file yourapp/templatetags/value_from_settings.py in which you define your own new tag value_from_settings:

from django.template import TemplateSyntaxError, Variable, Node, Variable, Library
from yourapp import settings

register = Library()
# I found some tricks in URLNode and url from defaulttags.py:
# https://code.djangoproject.com/browser/django/trunk/django/template/defaulttags.py
@register.tag
def value_from_settings(parser, token):
  bits = token.split_contents()
  if len(bits) < 2:
    raise TemplateSyntaxError("'%s' takes at least one " \
      "argument (settings constant to retrieve)" % bits[0])
  settingsvar = bits[1]
  settingsvar = settingsvar[1:-1] if settingsvar[0] == '"' else settingsvar
  asvar = None
  bits = bits[2:]
  if len(bits) >= 2 and bits[-2] == 'as':
    asvar = bits[-1]
    bits = bits[:-2]
  if len(bits):
    raise TemplateSyntaxError("'value_from_settings' didn't recognise " \
      "the arguments '%s'" % ", ".join(bits))
  return ValueFromSettings(settingsvar, asvar)

class ValueFromSettings(Node):
  def __init__(self, settingsvar, asvar):
    self.arg = Variable(settingsvar)
    self.asvar = asvar
  def render(self, context):
    ret_val = getattr(settings,str(self.arg))
    if self.asvar:
      context[self.asvar] = ret_val
      return ''
    else:
      return ret_val

You can use this tag in your Template via:

{% load value_from_settings %}
[...]
{% value_from_settings "FQDN" %}

or via

{% load value_from_settings %}
[...]
{% value_from_settings "FQDN" as my_fqdn %}

The advantage of the as ... notation is that this makes it easy to use in blocktrans blocks via a simple {{my_fqdn}}.

How can I get the URL of the current tab from a Google Chrome extension?

Other answers assume you want to know it from a popup or background script.

In case you want to know the current URL from a content script, the standard JS way applies:

window.location.toString()

You can use properties of window.location to access individual parts of the URL, such as host, protocol or path.

Automatically accept all SDK licences

I have encountered this with the alpha5 preview.

Jake Wharton pointed out to me that you can currently use

mkdir -p "$ANDROID_SDK/licenses"
echo -e "\n8933bad161af4178b1185d1a37fbf41ea5269c55" > "$ANDROID_SDK/licenses/android-sdk-license"
echo -e "\n84831b9409646a918e30573bab4c9c91346d8abd" > "$ANDROID_SDK/licenses/android-sdk-preview-license"

to recreate the current $ANDROID_HOME/license folder on you machine. This would have the same result as the process outlined in the link of the error msg (http://tools.android.com/tech-docs/new-build-system/license).

The hashes are sha1s of the licence text, which I imagine will be periodically updated, so this code will only work for so long :)

And install it manually, but it is the gradle's new feature purpose to do it.

I was surprised at first that this didnt work out of the box, even when I had accepted the licenses for the named components via the android tool, but it was pointed out to me its the SDK manager inside AS that creates the /licenses folder.

I guess that official tools would not want to skip this step for legal reasons.

Rereading the release notes it states

SDK auto-download: Gradle will attempt to download missing SDK packages that a project depends on.

Which does not mean it will work if you have not installed the android tools yet and have already accepted the latest license(s).

EDIT: Saying that, it still does not work on my test gubuntu box until I link the SDK up to AS. CI works fine though - not sure what the difference is...

How to display loading message when an iFrame is loading?

Yes, you could use a transparent div positioned over the iframe area, with a loader gif as only background.

Then you can attach an onload event to the iframe:

 $(document).ready(function() {

   $("iframe#id").load(function() {
      $("#loader-id").hide();
   });
});

PowerShell: Format-Table without headers

Try the -HideTableHeaders parameter to Format-Table:

gci | ft -HideTableHeaders

(I'm using PowerShell v2. I don't know if this was in v1.)

2D cross-platform game engine for Android and iOS?

Recently I used an AS3 engine: PushButton (now is dead, but it's still functional and you could use something else) to do this job. To make it works with Android and iOS, the project was compiled in AIR for both platforms and everything worked with no performance damage. Since Flash Builder is kinda expensive ($249), you could use FlashDevelop (there is some tutorials to compile in AIR with it).

Flash could be an option since is very easy to learn.

Laravel - Form Input - Multiple select for a one to many relationship

@SamMonk your technique is great. But you can use laravel form helper to do so. I have a customer and dogs relationship.

On your controller

$dogs = Dog::lists('name', 'id');

On customer create view you can use.

{{ Form::label('dogs', 'Dogs') }}
{{ Form::select('dogs[]', $dogs, null, ['id' => 'dogs', 'multiple' => 'multiple']) }}

Third parameter accepts a list of array a well. If you define a relationship on your model you can do this:

{{ Form::label('dogs', 'Dogs') }}
{{ Form::select('dogs[]', $dogs, $customer->dogs->lists('id'), ['id' => 'dogs', 'multiple' => 'multiple']) }}

Update For Laravel 5.1

The lists method now returns a Collection. Upgrading To 5.1.0

{!! Form::label('dogs', 'Dogs') !!}
{!! Form::select('dogs[]', $dogs, $customer->dogs->lists('id')->all(), ['id' => 'dogs', 'multiple' => 'multiple']) !!}

How can I stop a running MySQL query?

You need to run following command to kill the process. Find out the id of the process which you wanted to kill by

> show processlist;

Take the value from id column and fire below command

kill query <processId>;

Query parameter specifies that we need to kill query command process.

The syntax for kill process as follows

KILL [CONNECTION | QUERY] processlist_id

Please refer this link for more information.

VBA: Convert Text to Number

Using aLearningLady's answer above, you can make your selection range dynamic by looking for the last row with data in it instead of just selecting the entire column.

The below code worked for me.

Dim lastrow as Integer

lastrow = Cells(Rows.Count, 2).End(xlUp).Row

Range("C2:C" & lastrow).Select
With Selection
    .NumberFormat = "General"
    .Value = .Value
End With

Oracle date format picture ends before converting entire input string

I had this error today and discovered it was an incorrectly-formatted year...

select * from es_timeexpense where parsedate > to_date('12/3/2018', 'MM/dd/yyy')

Notice the year has only three 'y's. It should have 4.

Double-check your format.

Error:Execution failed for task ':app:compileDebugKotlin'. > Compilation error. See log for more details

I had a similar problem. The problem was that I incorrectly wrote the properties of the model in the attributes of the view:

<TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@{ferm.coin.value}"/> 

This part was wrong:

@{ferm.coin.value}

When I wrote the correct property, the error was resolved.

Select Top and Last rows in a table (SQL server)

You must sort your data according your needs (es. in reverse order) and use select top query

Why was the name 'let' chosen for block-scoped variable declarations in JavaScript?

I think JavaScript's indebtedness to Scheme is obvious here. Scheme not only has let, but has let*, let*-values, let-syntax, and let-values. (See, The Scheme Programming Language, 4th Ed.).

((The choice adds further credence to the notion that JavaScript is Lispy, but--before we get carried away--not homoiconic.))))

Changing website favicon dynamically

The favicon is declared in the head tag with something like:

<link rel="shortcut icon" type="image/ico" href="favicon.ico">

You should be able to just pass the name of the icon you want along in the view data and throw it into the head tag.

Simple CSS: Text won't center in a button

What about:

<input type="button" style="width:24px;" value="A"/>

Java: How to access methods from another class

Maybe you need some dependency injection

public class Alpha {

    private Beta cbeta;

    public Alpha(Beta beta) {
        this.cbeta = beta;
    }

    public void DoSomethingAlpha() {
        this.cbeta.DoSomethingBeta();
    }
}

and then

Alpha cAlpha = new Alpha(new Beta());   

How to set the margin or padding as percentage of height of parent container?

Here are two options to emulate the needed behavior. Not a general solution, but may help in some cases. The vertical spacing here is calculated on the basis of the size of the outer element, not its parent, but this size itself can be relative to the parent and this way the spacing will be relative too.

<div id="outer">
    <div id="inner">
        content
    </div>
</div>

First option: use pseudo-elements, here vertical and horizontal spacing are relative to the outer. Demo

#outer::before, #outer::after {
    display: block;
    content: "";
    height: 10%;
}
#inner {
    height: 80%;
    margin-left: 10%;
    margin-right: 10%;
}

Moving the horizontal spacing to the outer element makes it relative to the parent of the outer. Demo

#outer {
    padding-left: 10%;
    padding-right: 10%;
}

Second option: use absolute positioning. Demo

#outer {
    position: relative;
}
#inner {
    position: absolute;
    left: 10%;
    right: 10%;
    top: 10%;
    bottom: 10%;
}

Add timestamp column with default NOW() for new rows only

For example, I will create a table called users as below and give a column named date a default value NOW()

create table users_parent (
    user_id     varchar(50),
    full_name   varchar(240),
    login_id_1  varchar(50),
    date        timestamp NOT NULL DEFAULT NOW()
);

Thanks

Filter by Dates in SQL

WHERE dates BETWEEN (convert(datetime, '2012-12-12',110) AND (convert(datetime, '2012-12-12',110))

CryptographicException 'Keyset does not exist', but only through WCF

This is the only solution worked for me.

    // creates the CspParameters object and sets the key container name used to store the RSA key pair
    CspParameters cp = new CspParameters();
    cp.KeyContainerName = "MyKeyContainerName"; //Eg: Friendly name

    // instantiates the rsa instance accessing the key container MyKeyContainerName
    RSACryptoServiceProvider rsa = new RSACryptoServiceProvider(cp);
    // add the below line to delete the key entry in MyKeyContainerName
    // rsa.PersistKeyInCsp = false;

    //writes out the current key pair used in the rsa instance
    Console.WriteLine("Key is : \n" + rsa.ToXmlString(true));

Reference 1

Reference 2

python-pandas and databases like mysql

For Postgres users

import psycopg2
import pandas as pd

conn = psycopg2.connect("database='datawarehouse' user='user1' host='localhost' password='uberdba'")

customers = 'select * from customers'

customers_df = pd.read_sql(customers,conn)

customers_df

PHP + curl, HTTP POST sample code?

A simpler answer IF you are passing information to your own website is to use a SESSION variable. Begin php page with:

session_start();

If at some point there is information you want to generate in PHP and pass to the next page in the session, instead of using a POST variable, assign it to a SESSION variable. Example:

$_SESSION['message']='www.'.$_GET['school'].'.edu was not found.  Please try again.'

Then on the next page you simply reference this SESSION variable. NOTE: after you use it, be sure you destroy it, so it doesn't persist after it is used:

if (isset($_SESSION['message'])) {echo $_SESSION['message']; unset($_SESSION['message']);}

Android - SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length

Check if you have any element such as button or text view duplicated (copied twice) in the screen where this encounters. I did this unnoticed and had to face the same issue.

git recover deleted file where no commit was made after the delete

if you are looking for a deleted directory.

 git checkout ./pathToDir/*

How to find a number in a string using JavaScript?

I like @jesterjunk answer, however, a number is not always just digits. Consider those valid numbers: "123.5, 123,567.789, 12233234+E12"

So I just updated the regular expression:

var regex = /[\d|,|.|e|E|\+]+/g;

var string = "you can enter maximum 5,123.6 choices";
var matches = string.match(regex);  // creates array from matches

document.write(matches); //5,123.6

javax.net.ssl.SSLHandshakeException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found

After a some research i found the way to bypass ssl error Trust anchor for certification path not found. This might be not a good way to do but you can use it for a testing purpose.

 private HttpsURLConnection httpsUrlConnection( URL urlDownload) throws Exception {
  HttpsURLConnection connection=null;
        TrustManager[] trustAllCerts = new TrustManager[]{new X509TrustManager() {
            public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                return null;
            }

            @SuppressLint("TrustAllX509TrustManager")
            public void checkClientTrusted(X509Certificate[] certs, String authType) {
            }

            @SuppressLint("TrustAllX509TrustManager")
            public void checkServerTrusted(X509Certificate[] certs, String authType) {
            }
        }
        };
        SSLContext sc = SSLContext.getInstance("SSL"); // Add in try catch block if you get error.
        sc.init(null, trustAllCerts, new java.security.SecureRandom()); // Add in try catch block if you get error.
        HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());

        HostnameVerifier usnoHostnameVerifier = new HostnameVerifier() {
            @Override
            public boolean verify(String hostname, SSLSession session) {
                return true;
            }
        };

        SSLSocketFactory sslSocketFactory = sc.getSocketFactory();

        connection = (HttpsURLConnection) urlDownload.openConnection();
        connection.setHostnameVerifier(usnoHostnameVerifier);
        connection.setSSLSocketFactory(sslSocketFactory);

        return connection;
    }

eval command in Bash and its typical uses

The eval statement tells the shell to take eval’s arguments as command and run them through the command-line. It is useful in a situation like below:

In your script if you are defining a command into a variable and later on you want to use that command then you should use eval:

/home/user1 > a="ls | more"
/home/user1 > $a
bash: command not found: ls | more
/home/user1 > # Above command didn't work as ls tried to list file with name pipe (|) and more. But these files are not there
/home/user1 > eval $a
file.txt
mailids
remote_cmd.sh
sample.txt
tmp
/home/user1 >

Edit a text file on the console using Powershell

Well there are thousand ways to edit a Text file on windows 7. Usually people Install Sublime , Atom and Notepad++ as an editor. For command line , I think the Basic Edit command (by the way which does not work on 64 bit computers) is good;Alternatively I find type con > filename as a very Applaudable method.If windows is newly installed and One wants to avoid Notepad. This might be it!! The perfect usage of Type as an editor :)

reference of the Image:- https://www.codeproject.com/Articles/34280/How-to-Write-Applet-Code

How do I use installed packages in PyCharm?

For PyCharm Community Edition 2016.3.2 it is:

"Project Interpreter" -> Top right settings icon -> "More".

Then on the right side there should be a packages icon. When hovering over it it should say "Show paths for selected interpreter". Click it.

Then click the "Add" button or press "alt+insert" to add a new path.

How can I convert an image into a Base64 string?

Use this code:

byte[] decodedString = Base64.decode(Base64String.getBytes(), Base64.DEFAULT);

Bitmap decodedByte = BitmapFactory.decodeByteArray(decodedString, 0, decodedString.length);

phpmailer: Reply using only "Reply To" address

At least in the current versions of PHPMailers, there's a function clearReplyTos() to empty the reply-to array.

    $mail->ClearReplyTos();
    $mail->addReplyTo([email protected], 'EXAMPLE');

Gradient of n colors ranging from color 1 and color 2

colorRampPalette could be your friend here:

colfunc <- colorRampPalette(c("black", "white"))
colfunc(10)
# [1] "#000000" "#1C1C1C" "#383838" "#555555" "#717171" "#8D8D8D" "#AAAAAA"
# [8] "#C6C6C6" "#E2E2E2" "#FFFFFF"

And just to show it works:

plot(rep(1,10),col=colfunc(10),pch=19,cex=3)

enter image description here

Calculating powers of integers

No, there is not something as short as a**b

Here is a simple loop, if you want to avoid doubles:

long result = 1;
for (int i = 1; i <= b; i++) {
   result *= a;
}

If you want to use pow and convert the result in to integer, cast the result as follows:

int result = (int)Math.pow(a, b);

DateTimeFormat in TypeScript

This should work...

var displayDate = new Date().toLocaleDateString();

alert(displayDate);

But I suspect you are trying it on something else, for example:

var displayDate = Date.now.toLocaleDateString(); // No!

alert(displayDate);

Multiple simultaneous downloads using Wget?

Wget does not support multiple socket connections in order to speed up download of files.

I think we can do a bit better than gmarian answer.

The correct way is to use aria2.

aria2c -x 16 -s 16 [url]
#          |    |
#          |    |
#          |    |
#          ---------> the number of connections here

How to get html table td cell value by JavaScript?

Don't use in-line JavaScript, separate your behaviour from your data and it gets much easier to handle. I'd suggest the following:

var table = document.getElementById('tableID'),
    cells = table.getElementsByTagName('td');

for (var i=0,len=cells.length; i<len; i++){
    cells[i].onclick = function(){
        console.log(this.innerHTML);
        /* if you know it's going to be numeric:
        console.log(parseInt(this.innerHTML),10);
        */
    }
}

_x000D_
_x000D_
var table = document.getElementById('tableID'),_x000D_
  cells = table.getElementsByTagName('td');_x000D_
_x000D_
for (var i = 0, len = cells.length; i < len; i++) {_x000D_
  cells[i].onclick = function() {_x000D_
    console.log(this.innerHTML);_x000D_
  };_x000D_
}
_x000D_
th,_x000D_
td {_x000D_
  border: 1px solid #000;_x000D_
  padding: 0.2em 0.3em 0.1em 0.3em;_x000D_
}
_x000D_
<table id="tableID">_x000D_
  <thead>_x000D_
    <tr>_x000D_
      <th>Column heading 1</th>_x000D_
      <th>Column heading 2</th>_x000D_
      <th>Column heading 3</th>_x000D_
      <th>Column heading 4</th>_x000D_
    </tr>_x000D_
  </thead>_x000D_
  <tbody>_x000D_
    <tr>_x000D_
      <td>43</td>_x000D_
      <td>23</td>_x000D_
      <td>89</td>_x000D_
      <td>5</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>4</td>_x000D_
      <td>3</td>_x000D_
      <td>0</td>_x000D_
      <td>98</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>10</td>_x000D_
      <td>32</td>_x000D_
      <td>7</td>_x000D_
      <td>2</td>_x000D_
    </tr>_x000D_
  </tbody>_x000D_
</table>
_x000D_
_x000D_
_x000D_

JS Fiddle proof-of-concept.

A revised approach, in response to the comment (below):

You're missing a semicolon. Also, don't make functions within a loop.

This revision binds a (single) named function as the click event-handler of the multiple <td> elements, and avoids the unnecessary overhead of creating multiple anonymous functions within a loop (which is poor practice due to repetition and the impact on performance, due to memory usage):

function logText() {
  // 'this' is automatically passed to the named
  // function via the use of addEventListener()
  // (later):
  console.log(this.textContent);
}

// using a CSS Selector, with document.querySelectorAll()
// to get a NodeList of <td> elements within the #tableID element:
var cells = document.querySelectorAll('#tableID td');

// iterating over the array-like NodeList, using
// Array.prototype.forEach() and Function.prototype.call():
Array.prototype.forEach.call(cells, function(td) {
  // the first argument of the anonymous function (here: 'td')
  // is the element of the array over which we're iterating.

  // adding an event-handler (the function logText) to handle
  // the click events on the <td> elements:
  td.addEventListener('click', logText);
});

_x000D_
_x000D_
function logText() {_x000D_
  console.log(this.textContent);_x000D_
}_x000D_
_x000D_
var cells = document.querySelectorAll('#tableID td');_x000D_
_x000D_
Array.prototype.forEach.call(cells, function(td) {_x000D_
  td.addEventListener('click', logText);_x000D_
});
_x000D_
th,_x000D_
td {_x000D_
  border: 1px solid #000;_x000D_
  padding: 0.2em 0.3em 0.1em 0.3em;_x000D_
}
_x000D_
<table id="tableID">_x000D_
  <thead>_x000D_
    <tr>_x000D_
      <th>Column heading 1</th>_x000D_
      <th>Column heading 2</th>_x000D_
      <th>Column heading 3</th>_x000D_
      <th>Column heading 4</th>_x000D_
    </tr>_x000D_
  </thead>_x000D_
  <tbody>_x000D_
    <tr>_x000D_
      <td>43</td>_x000D_
      <td>23</td>_x000D_
      <td>89</td>_x000D_
      <td>5</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>4</td>_x000D_
      <td>3</td>_x000D_
      <td>0</td>_x000D_
      <td>98</td>_x000D_
    </tr>_x000D_
    <tr>_x000D_
      <td>10</td>_x000D_
      <td>32</td>_x000D_
      <td>7</td>_x000D_
      <td>2</td>_x000D_
    </tr>_x000D_
  </tbody>_x000D_
</table>
_x000D_
_x000D_
_x000D_

JS Fiddle proof-of-concept.

References:

How to remove part of a string?

My favourite way of doing this is "splitting and popping":

var str = "test_23";
alert(str.split("_").pop());
// -> 23

var str2 = "adifferenttest_153";
alert(str2.split("_").pop());
// -> 153

split() splits a string into an array of strings using a specified separator string.
pop() removes the last element from an array and returns that element.

how to remove css property using javascript?

You have two options:

OPTION 1:

You can use removeProperty method. It will remove a style from an element.

el.style.removeProperty('zoom');

OPTION 2:

You can set it to the default value:

el.style.zoom = "";

The effective zoom will now be whatever follows from the definitions set in the stylesheets (through link and style tags). So this syntax will only modify the local style of this element.

How to use the IEqualityComparer

If you want a generic solution without boxing:

public class KeyBasedEqualityComparer<T, TKey> : IEqualityComparer<T>
{
    private readonly Func<T, TKey> _keyGetter;

    public KeyBasedEqualityComparer(Func<T, TKey> keyGetter)
    {
        _keyGetter = keyGetter;
    }

    public bool Equals(T x, T y)
    {
        return EqualityComparer<TKey>.Default.Equals(_keyGetter(x), _keyGetter(y));
    }

    public int GetHashCode(T obj)
    {
        TKey key = _keyGetter(obj);

        return key == null ? 0 : key.GetHashCode();
    }
}

public static class KeyBasedEqualityComparer<T>
{
    public static KeyBasedEqualityComparer<T, TKey> Create<TKey>(Func<T, TKey> keyGetter)
    {
        return new KeyBasedEqualityComparer<T, TKey>(keyGetter);
    }
}

usage:

KeyBasedEqualityComparer<Class_reglement>.Create(x => x.Numf)

Does JavaScript pass by reference?

Primitives are passed by value. But in case you only need to read the value of a primitve (and value is not known at the time when function is called) you can pass function which retrieves the value at the moment you need it.

function test(value) {
  console.log('retrieve value');
  console.log(value());
}

// call the function like this
var value = 1;
test(() => value);

How to calculate age (in years) based on Date of Birth and getDate()

There are issues with leap year/days and the following method, see the update below:

try this:

DECLARE @dob  datetime
SET @dob='1992-01-09 00:00:00'

SELECT DATEDIFF(hour,@dob,GETDATE())/8766.0 AS AgeYearsDecimal
    ,CONVERT(int,ROUND(DATEDIFF(hour,@dob,GETDATE())/8766.0,0)) AS AgeYearsIntRound
    ,DATEDIFF(hour,@dob,GETDATE())/8766 AS AgeYearsIntTrunc

OUTPUT:

AgeYearsDecimal                         AgeYearsIntRound AgeYearsIntTrunc
--------------------------------------- ---------------- ----------------
17.767054                               18               17

(1 row(s) affected)

UPDATE here are some more accurate methods:

BEST METHOD FOR YEARS IN INT

DECLARE @Now  datetime, @Dob datetime
SELECT   @Now='1990-05-05', @Dob='1980-05-05'  --results in 10
--SELECT @Now='1990-05-04', @Dob='1980-05-05'  --results in  9
--SELECT @Now='1989-05-06', @Dob='1980-05-05'  --results in  9
--SELECT @Now='1990-05-06', @Dob='1980-05-05'  --results in 10
--SELECT @Now='1990-12-06', @Dob='1980-05-05'  --results in 10
--SELECT @Now='1991-05-04', @Dob='1980-05-05'  --results in 10

SELECT
    (CONVERT(int,CONVERT(char(8),@Now,112))-CONVERT(char(8),@Dob,112))/10000 AS AgeIntYears

you can change the above 10000 to 10000.0 and get decimals, but it will not be as accurate as the method below.

BEST METHOD FOR YEARS IN DECIMAL

DECLARE @Now  datetime, @Dob datetime
SELECT   @Now='1990-05-05', @Dob='1980-05-05' --results in 10.000000000000
--SELECT @Now='1990-05-04', @Dob='1980-05-05' --results in  9.997260273973
--SELECT @Now='1989-05-06', @Dob='1980-05-05' --results in  9.002739726027
--SELECT @Now='1990-05-06', @Dob='1980-05-05' --results in 10.002739726027
--SELECT @Now='1990-12-06', @Dob='1980-05-05' --results in 10.589041095890
--SELECT @Now='1991-05-04', @Dob='1980-05-05' --results in 10.997260273973

SELECT 1.0* DateDiff(yy,@Dob,@Now) 
    +CASE 
         WHEN @Now >= DATEFROMPARTS(DATEPART(yyyy,@Now),DATEPART(m,@Dob),DATEPART(d,@Dob)) THEN  --birthday has happened for the @now year, so add some portion onto the year difference
           (  1.0   --force automatic conversions from int to decimal
              * DATEDIFF(day,DATEFROMPARTS(DATEPART(yyyy,@Now),DATEPART(m,@Dob),DATEPART(d,@Dob)),@Now) --number of days difference between the @Now year birthday and the @Now day
              / DATEDIFF(day,DATEFROMPARTS(DATEPART(yyyy,@Now),1,1),DATEFROMPARTS(DATEPART(yyyy,@Now)+1,1,1)) --number of days in the @Now year
           )
         ELSE  --birthday has not been reached for the last year, so remove some portion of the year difference
           -1 --remove this fractional difference onto the age
           * (  -1.0   --force automatic conversions from int to decimal
                * DATEDIFF(day,DATEFROMPARTS(DATEPART(yyyy,@Now),DATEPART(m,@Dob),DATEPART(d,@Dob)),@Now) --number of days difference between the @Now year birthday and the @Now day
                / DATEDIFF(day,DATEFROMPARTS(DATEPART(yyyy,@Now),1,1),DATEFROMPARTS(DATEPART(yyyy,@Now)+1,1,1)) --number of days in the @Now year
             )
     END AS AgeYearsDecimal

Why am I seeing "TypeError: string indices must be integers"?

As a rule of thumb, when I receive this error in Python I compare the function signature with the function execution.

For example:

def print_files(file_list, parent_id):
    for file in file_list:
        print(title: %s, id: %s' % (file['title'], file['id']

So if I'll call this function with parameters placed in the wrong order and pass the list as the 2nd argument and a string as the 1st argument:

print_files(parent_id, list_of_files) # <----- Accidentally switching arguments location

The function will try to iterate over the parent_id string instead of file_list and it will expect to see the index as an integer pointing to the specific character in string and not an index which is a string (title or id).

This will lead to the TypeError: string indices must be integers error.

Due to its dynamic nature (as opposed to languages like Java, C# or Typescript), Python will not inform you about this syntax error.

Creating a Shopping Cart using only HTML/JavaScript

Here's a one page cart written in Javascript with localStorage. Here's a full working pen. Previously found on Codebox

cart.js

var cart = {
  // (A) PROPERTIES
  hPdt : null, // HTML products list
  hItems : null, // HTML current cart
  items : {}, // Current items in cart

  // (B) LOCALSTORAGE CART
  // (B1) SAVE CURRENT CART INTO LOCALSTORAGE
  save : function () {
    localStorage.setItem("cart", JSON.stringify(cart.items));
  },

  // (B2) LOAD CART FROM LOCALSTORAGE
  load : function () {
    cart.items = localStorage.getItem("cart");
    if (cart.items == null) { cart.items = {}; }
    else { cart.items = JSON.parse(cart.items); }
  },

  // (B3) EMPTY ENTIRE CART
  nuke : function () {
    if (confirm("Empty cart?")) {
      cart.items = {};
      localStorage.removeItem("cart");
      cart.list();
    }
  },

  // (C) INITIALIZE
  init : function () {
    // (C1) GET HTML ELEMENTS
    cart.hPdt = document.getElementById("cart-products");
    cart.hItems = document.getElementById("cart-items");

    // (C2) DRAW PRODUCTS LIST
    cart.hPdt.innerHTML = "";
    let p, item, part;
    for (let id in products) {
      // WRAPPER
      p = products[id];
      item = document.createElement("div");
      item.className = "p-item";
      cart.hPdt.appendChild(item);

      // PRODUCT IMAGE
      part = document.createElement("img");
      part.src = "images/" +p.img;
      part.className = "p-img";
      item.appendChild(part);

      // PRODUCT NAME
      part = document.createElement("div");
      part.innerHTML = p.name;
      part.className = "p-name";
      item.appendChild(part);

      // PRODUCT DESCRIPTION
      part = document.createElement("div");
      part.innerHTML = p.desc;
      part.className = "p-desc";
      item.appendChild(part);

      // PRODUCT PRICE
      part = document.createElement("div");
      part.innerHTML = "$" + p.price;
      part.className = "p-price";
      item.appendChild(part);

      // ADD TO CART
      part = document.createElement("input");
      part.type = "button";
      part.value = "Add to Cart";
      part.className = "cart p-add";
      part.onclick = cart.add;
      part.dataset.id = id;
      item.appendChild(part);
    }

    // (C3) LOAD CART FROM PREVIOUS SESSION
    cart.load();

    // (C4) LIST CURRENT CART ITEMS
    cart.list();
  },

  // (D) LIST CURRENT CART ITEMS (IN HTML)
  list : function () {
    // (D1) RESET
    cart.hItems.innerHTML = "";
    let item, part, pdt;
    let empty = true;
    for (let key in cart.items) {
      if(cart.items.hasOwnProperty(key)) { empty = false; break; }
    }

    // (D2) CART IS EMPTY
    if (empty) {
      item = document.createElement("div");
      item.innerHTML = "Cart is empty";
      cart.hItems.appendChild(item);
    }

    // (D3) CART IS NOT EMPTY - LIST ITEMS
    else {
      let p, total = 0, subtotal = 0;
      for (let id in cart.items) {
        // ITEM
        p = products[id];
        item = document.createElement("div");
        item.className = "c-item";
        cart.hItems.appendChild(item);

        // NAME
        part = document.createElement("div");
        part.innerHTML = p.name;
        part.className = "c-name";
        item.appendChild(part);

        // REMOVE
        part = document.createElement("input");
        part.type = "button";
        part.value = "X";
        part.dataset.id = id;
        part.className = "c-del cart";
        part.addEventListener("click", cart.remove);
        item.appendChild(part);

        // QUANTITY
        part = document.createElement("input");
        part.type = "number";
        part.value = cart.items[id];
        part.dataset.id = id;
        part.className = "c-qty";
        part.addEventListener("change", cart.change);
        item.appendChild(part);

        // SUBTOTAL
        subtotal = cart.items[id] * p.price;
        total += subtotal;
      }

      // EMPTY BUTTONS
      item = document.createElement("input");
      item.type = "button";
      item.value = "Empty";
      item.addEventListener("click", cart.nuke);
      item.className = "c-empty cart";
      cart.hItems.appendChild(item);

      // CHECKOUT BUTTONS
      item = document.createElement("input");
      item.type = "button";
      item.value = "Checkout - " + "$" + total;
      item.addEventListener("click", cart.checkout);
      item.className = "c-checkout cart";
      cart.hItems.appendChild(item);
    }
  },

  // (E) ADD ITEM INTO CART
  add : function () {
    if (cart.items[this.dataset.id] == undefined) {
      cart.items[this.dataset.id] = 1;
    } else {
      cart.items[this.dataset.id]++;
    }
    cart.save();
    cart.list();
  },

  // (F) CHANGE QUANTITY
  change : function () {
    if (this.value == 0) {
      delete cart.items[this.dataset.id];
    } else {
      cart.items[this.dataset.id] = this.value;
    }
    cart.save();
    cart.list();
  },
  
  // (G) REMOVE ITEM FROM CART
  remove : function () {
    delete cart.items[this.dataset.id];
    cart.save();
    cart.list();
  },
  
  // (H) CHECKOUT
  checkout : function () {
    // SEND DATA TO SERVER
    // CHECKS
    // SEND AN EMAIL
    // RECORD TO DATABASE
    // PAYMENT
    // WHATEVER IS REQUIRED
    alert("TO DO");

    /*
    var data = new FormData();
    data.append('cart', JSON.stringify(cart.items));
    data.append('products', JSON.stringify(products));
    var xhr = new XMLHttpRequest();
    xhr.open("POST", "SERVER-SCRIPT");
    xhr.onload = function(){ ... };
    xhr.send(data);
    */
  }
};
window.addEventListener("DOMContentLoaded", cart.init);

How to reset or change the passphrase for a GitHub SSH key?

  1. Log in to your github account.
  2. Go to the "Settings" page (the "wrench and screwdriver" icon in the top right corner of the page).
  3. Go to "SSH keys" page.
  4. Generate a new SSH key (probably studying the links provided by github on that page).
  5. Add your new key using the "Add SSH key" link.
  6. Verify your new key works.
  7. Make gitub forget your old key by using the "Delete" link next to it in the list of known keys.

Calculating difference between two timestamps in Oracle in milliseconds

When you subtract two variables of type TIMESTAMP, you get an INTERVAL DAY TO SECOND which includes a number of milliseconds and/or microseconds depending on the platform. If the database is running on Windows, systimestamp will generally have milliseconds. If the database is running on Unix, systimestamp will generally have microseconds.

  1  select systimestamp - to_timestamp( '2012-07-23', 'yyyy-mm-dd' )
  2*   from dual
SQL> /

SYSTIMESTAMP-TO_TIMESTAMP('2012-07-23','YYYY-MM-DD')
---------------------------------------------------------------------------
+000000000 14:51:04.339000000

You can use the EXTRACT function to extract the individual elements of an INTERVAL DAY TO SECOND

SQL> ed
Wrote file afiedt.buf

  1  select extract( day from diff ) days,
  2         extract( hour from diff ) hours,
  3         extract( minute from diff ) minutes,
  4         extract( second from diff ) seconds
  5    from (select systimestamp - to_timestamp( '2012-07-23', 'yyyy-mm-dd' ) diff
  6*           from dual)
SQL> /

      DAYS      HOURS    MINUTES    SECONDS
---------- ---------- ---------- ----------
         0         14         55     37.936

You can then convert each of those components into milliseconds and add them up

SQL> ed
Wrote file afiedt.buf

  1  select extract( day from diff )*24*60*60*1000 +
  2         extract( hour from diff )*60*60*1000 +
  3         extract( minute from diff )*60*1000 +
  4         round(extract( second from diff )*1000) total_milliseconds
  5    from (select systimestamp - to_timestamp( '2012-07-23', 'yyyy-mm-dd' ) diff
  6*           from dual)
SQL> /

TOTAL_MILLISECONDS
------------------
          53831842

Normally, however, it is more useful to have either the INTERVAL DAY TO SECOND representation or to have separate columns for hours, minutes, seconds, etc. rather than computing the total number of milliseconds between two TIMESTAMP values.

Laravel - htmlspecialchars() expects parameter 1 to be string, object given

When you use a blade echo {{ $data }} it will automatically escape the output. It can only escape strings. In your data $data->ac is an array and $data is an object, neither of which can be echoed as is. You need to be more specific of how the data should be outputted. What exactly that looks like entirely depends on what you're trying to accomplish. For example to display the link you would need to do {{ $data->ac[0][0]['url'] }} (not sure why you have two nested arrays but I'm just following your data structure).

@foreach($data->ac['0'] as $link)
    <a href="{{ $link['url'] }}">This is a link</a>
@endforeach

Track a new remote branch created on GitHub

When the branch is no remote branch you can push your local branch direct to the remote.

git checkout master
git push origin master

or when you have a dev branch

git checkout dev
git push origin dev

or when the remote branch exists

git branch dev -t origin/dev

There are some other posibilites to push a remote branch.

How do I make a matrix from a list of vectors in R?

Not straightforward, but it works:

> t(sapply(a, unlist))
      [,1] [,2] [,3] [,4] [,5] [,6]
 [1,]    1    1    2    3    4    5
 [2,]    2    1    2    3    4    5
 [3,]    3    1    2    3    4    5
 [4,]    4    1    2    3    4    5
 [5,]    5    1    2    3    4    5
 [6,]    6    1    2    3    4    5
 [7,]    7    1    2    3    4    5
 [8,]    8    1    2    3    4    5
 [9,]    9    1    2    3    4    5
[10,]   10    1    2    3    4    5

Java - Abstract class to contain variables?

Sure.. Why not?
Abstract base classes are just a convenience to house behavior and data common to 2 or more classes in a single place for efficiency of storage and maintenance. Its an implementation detail.
Take care however that you are not using an abstract base class where you should be using an interface. Refer to Interface vs Base class

Is there an opposite to display:none?

I use display:block; It works for me

Console logging for react?

If you're just after console logging here's what I'd do:

export default class App extends Component {
  componentDidMount() {
    console.log('I was triggered during componentDidMount')
  }

  render() {
    console.log('I was triggered during render')
    return ( 
      <div> I am the App component </div>
    )
  }
}

Shouldn't be any need for those packages just to do console logging.

How to check that Request.QueryString has a specific value or not in ASP.NET?

What about a more direct approach?

if (Request.QueryString.AllKeys.Contains("mykey")

Get screen width and height in Android

Get the value of screen width and height.

Display display = getWindowManager().getDefaultDisplay();
Point size = new Point();
display.getSize(size);
width = size.x;
height = size.y;

Difference between framework vs Library vs IDE vs API vs SDK vs Toolkits?

In other words...

IDE Even your notepad is an IDE. Every software you write/compile code with is an IDE.

Library A bunch of code which simplifies functions/methods for quick use.

API A programming interface for functions/configuration which you work with, its usage is often documented.

SDK Extras and/or for development/testing purposes.

ToolKit Tiny apps for quick use, often GUIs.

GUI Apps with a graphical interface, requires no knowledge of programming unlike APIs.

Framework Bunch of APIs/huge Library/Snippets wrapped in a namespace/or encapsulated from outer scope for compact handling without conflicts with other code.

MVC A design pattern separated in Models, Views and Controllers for huge applications. They are not dependent on each other and can be changed/improved/replaced without to take care of other code.

Example:

Car (Model)
The object that is being presented.
Example in IT: A HTML form.


Camera (View)
Something that is able to see the object(car).
Example in IT: Browser that renders a website with the form.


Driver (Controller)
Someone who drives that car.
Example in IT: Functions which handle form data that's being submitted.

Snippets Small codes of only a few lines, may not be even complete but worth for a quick share.

Plug-ins Exclusive functions for specified frameworks/APIs/libraries only.

Add-ons Additional modules or services for specific GUIs.

Huge performance difference when using group by vs distinct

The two queries express the same question. Apparently the query optimizer chooses two different execution plans. My guess would be that the distinct approach is executed like:

  • Copy all business_key values to a temporary table
  • Sort the temporary table
  • Scan the temporary table, returning each item that is different from the one before it

The group by could be executed like:

  • Scan the full table, storing each value of business key in a hashtable
  • Return the keys of the hashtable

The first method optimizes for memory usage: it would still perform reasonably well when part of the temporary table has to be swapped out. The second method optimizes for speed, but potentially requires a large amount of memory if there are a lot of different keys.

Since you either have enough memory or few different keys, the second method outperforms the first. It's not unusual to see performance differences of 10x or even 100x between two execution plans.

How do I write a backslash (\) in a string?

Just escape the "\" by using + "\\Tasks" or use a verbatim string like @"\Tasks"

HttpWebRequest-The remote server returned an error: (400) Bad Request

Are you sure you should be using POST not PUT?

POST is usually used with application/x-www-urlencoded formats. If you are using a REST API, you should maybe be using PUT? If you are uploading a file you probably need to use multipart/form-data. Not always, but usually, that is the right thing to do..

Also you don't seem to be using the credentials to log in - you need to use the Credentials property of the HttpWebRequest object to send the username and password.

How to delete mysql database through shell command

You can remove database directly as:

$ mysqladmin -h [host] -u [user] -p drop [database_name]

[Enter Password]

Do you really want to drop the 'hairfree' database [y/N]: y

How does #include <bits/stdc++.h> work in C++?

Unfortunately that approach is not portable C++ (so far).

All standard names are in namespace std and moreover you cannot know which names are NOT defined by including and header (in other words it's perfectly legal for an implementation to declare the name std::string directly or indirectly when using #include <vector>).

Despite this however you are required by the language to know and tell the compiler which standard header includes which part of the standard library. This is a source of portability bugs because if you forget for example #include <map> but use std::map it's possible that the program compiles anyway silently and without warnings on a specific version of a specific compiler, and you may get errors only later when porting to another compiler or version.

In my opinion there are no valid technical excuses because this is necessary for the general user: the compiler binary could have all standard namespace built in and this could actually increase the performance even more than precompiled headers (e.g. using perfect hashing for lookups, removing standard headers parsing or loading/demarshalling and so on).

The use of standard headers simplifies the life of who builds compilers or standard libraries and that's all. It's not something to help users.

However this is the way the language is defined and you need to know which header defines which names so plan for some extra neurons to be burnt in pointless configurations to remember that (or try to find and IDE that automatically adds the standard headers you use and removes the ones you don't... a reasonable alternative).

How can I get a list of users from active directory?

If you are new to Active Directory, I suggest you should understand how Active Directory stores data first.

Active Directory is actually a LDAP server. Objects stored in LDAP server are stored hierarchically. It's very similar to you store your files in your file system. That's why it got the name Directory server and Active Directory

The containers and objects on Active Directory can be specified by a distinguished name. The distinguished name is like this CN=SomeName,CN=SomeDirectory,DC=yourdomain,DC=com. Like a traditional relational database, you can run query against a LDAP server. It's called LDAP query.

There are a number of ways to run a LDAP query in .NET. You can use DirectorySearcher from System.DirectoryServices or SearchRequest from System.DirectoryServices.Protocol.

For your question, since you are asking to find user principal object specifically, I think the most intuitive way is to use PrincipalSearcher from System.DirectoryServices.AccountManagement. You can easily find a lot of different examples from google. Here is a sample that is doing exactly what you are asking for.

using (var context = new PrincipalContext(ContextType.Domain, "yourdomain.com"))
{
    using (var searcher = new PrincipalSearcher(new UserPrincipal(context)))
    {
        foreach (var result in searcher.FindAll())
        {
            DirectoryEntry de = result.GetUnderlyingObject() as DirectoryEntry;
            Console.WriteLine("First Name: " + de.Properties["givenName"].Value);
            Console.WriteLine("Last Name : " + de.Properties["sn"].Value);
            Console.WriteLine("SAM account name   : " + de.Properties["samAccountName"].Value);
            Console.WriteLine("User principal name: " + de.Properties["userPrincipalName"].Value);
            Console.WriteLine();
        }
    }
}
Console.ReadLine();

Note that on the AD user object, there are a number of attributes. In particular, givenName will give you the First Name and sn will give you the Last Name. About the user name. I think you meant the user logon name. Note that there are two logon names on AD user object. One is samAccountName, which is also known as pre-Windows 2000 user logon name. userPrincipalName is generally used after Windows 2000.

Left Outer Join using + sign in Oracle 11g

LEFT OUTER JOIN

SELECT * FROM A, B WHERE A.column = B.column(+)

RIGHT OUTER JOIN

SELECT * FROM A, B WHERE A.column (+)= B.column

How to clear the logs properly for a Docker container?

You can set up logrotate to clear the logs periodically.

Example file in /etc/logrotate.d/docker-logs

/var/lib/docker/containers/*/*.log {
 rotate 7
 daily
 compress
 size=50M
 missingok
 delaycompress
 copytruncate
}

Setting default values for columns in JPA

You can define the default value in the database designer, or when you create the table. For instance in SQL Server you can set the default vault of a Date field to (getDate()). Use insertable=false as mentioned in your column definition. JPA will not specify that column on inserts and the database will generate the value for you.

Difference between onLoad and ng-init in angular

Works for me.

<div ng-show="$scope.showme === true">Hello World</div>
<div ng-repeat="a in $scope.bigdata" ng-init="$scope.showme = true">{{ a.title }}</div>

How to call a function from another controller in angularjs?

Communication between controllers is done though $emit + $on / $broadcast + $on methods.

So in your case you want to call a method of Controller "One" inside Controller "Two", the correct way to do this is:

app.controller('One', ['$scope', '$rootScope'
    function($scope) {
        $rootScope.$on("CallParentMethod", function(){
           $scope.parentmethod();
        });

        $scope.parentmethod = function() {
            // task
        }
    }
]);
app.controller('two', ['$scope', '$rootScope'
    function($scope) {
        $scope.childmethod = function() {
            $rootScope.$emit("CallParentMethod", {});
        }
    }
]);

While $rootScope.$emit is called, you can send any data as second parameter.

update package.json version automatically

As an addition to npm version you can use the --no-git-tag-version flag if you want a version bump but no tag or a new commit:

npm --no-git-tag-version version patch

https://docs.npmjs.com/cli/version

Count number of 1's in binary representation

There's only one way I can think of to accomplish this task in O(1)... that is to 'cheat' and use a physical device (with linear or even parallel programming I think the limit is O(log(k)) where k represents the number of bytes of the number).

However you could very easily imagine a physical device that connects each bit an to output line with a 0/1 voltage. Then you could just electronically read of the total voltage on a 'summation' line in O(1). It would be quite easy to make this basic idea more elegant with some basic circuit elements to produce the output in whatever form you want (e.g. a binary encoded output), but the essential idea is the same and the electronic circuit would produce the correct output state in fixed time.

I imagine there are also possible quantum computing possibilities, but if we're allowed to do that, I would think a simple electronic circuit is the easier solution.

Git status ignore line endings / identical files / windows & linux environment / dropbox / mled

Issue related to git commands on Windows operating system:

$ git add --all

warning: LF will be replaced by CRLF in ...

The file will have its original line endings in your working directory.

Resolution:

$ git config --global core.autocrlf false     
$ git add --all 

No any warning messages come up.

Adding ASP.NET MVC5 Identity Authentication to an existing project

Configuring Identity to your existing project is not hard thing. You must install some NuGet package and do some small configuration.

First install these NuGet packages with Package Manager Console:

PM> Install-Package Microsoft.AspNet.Identity.Owin 
PM> Install-Package Microsoft.AspNet.Identity.EntityFramework
PM> Install-Package Microsoft.Owin.Host.SystemWeb 

Add a user class and with IdentityUser inheritance:

public class AppUser : IdentityUser
{
    //add your custom properties which have not included in IdentityUser before
    public string MyExtraProperty { get; set; }  
}

Do same thing for role:

public class AppRole : IdentityRole
{
    public AppRole() : base() { }
    public AppRole(string name) : base(name) { }
    // extra properties here 
}

Change your DbContext parent from DbContext to IdentityDbContext<AppUser> like this:

public class MyDbContext : IdentityDbContext<AppUser>
{
    // Other part of codes still same 
    // You don't need to add AppUser and AppRole 
    // since automatically added by inheriting form IdentityDbContext<AppUser>
}

If you use the same connection string and enabled migration, EF will create necessary tables for you.

Optionally, you could extend UserManager to add your desired configuration and customization:

public class AppUserManager : UserManager<AppUser>
{
    public AppUserManager(IUserStore<AppUser> store)
        : base(store)
    {
    }

    // this method is called by Owin therefore this is the best place to configure your User Manager
    public static AppUserManager Create(
        IdentityFactoryOptions<AppUserManager> options, IOwinContext context)
    {
        var manager = new AppUserManager(
            new UserStore<AppUser>(context.Get<MyDbContext>()));

        // optionally configure your manager
        // ...

        return manager;
    }
}

Since Identity is based on OWIN you need to configure OWIN too:

Add a class to App_Start folder (or anywhere else if you want). This class is used by OWIN. This will be your startup class.

namespace MyAppNamespace
{
    public class IdentityConfig
    {
        public void Configuration(IAppBuilder app)
        {
            app.CreatePerOwinContext(() => new MyDbContext());
            app.CreatePerOwinContext<AppUserManager>(AppUserManager.Create);
            app.CreatePerOwinContext<RoleManager<AppRole>>((options, context) =>
                new RoleManager<AppRole>(
                    new RoleStore<AppRole>(context.Get<MyDbContext>())));

            app.UseCookieAuthentication(new CookieAuthenticationOptions
            {
                AuthenticationType = DefaultAuthenticationTypes.ApplicationCookie,
                LoginPath = new PathString("/Home/Login"),
            });
        }
    }
}

Almost done just add this line of code to your web.config file so OWIN could find your startup class.

<appSettings>
    <!-- other setting here -->
    <add key="owin:AppStartup" value="MyAppNamespace.IdentityConfig" />
</appSettings>

Now in entire project you could use Identity just like any new project had already installed by VS. Consider login action for example

[HttpPost]
public ActionResult Login(LoginViewModel login)
{
    if (ModelState.IsValid)
    {
        var userManager = HttpContext.GetOwinContext().GetUserManager<AppUserManager>();
        var authManager = HttpContext.GetOwinContext().Authentication;

        AppUser user = userManager.Find(login.UserName, login.Password);
        if (user != null)
        {
            var ident = userManager.CreateIdentity(user, 
                DefaultAuthenticationTypes.ApplicationCookie);
            //use the instance that has been created. 
            authManager.SignIn(
                new AuthenticationProperties { IsPersistent = false }, ident);
            return Redirect(login.ReturnUrl ?? Url.Action("Index", "Home"));
        }
    }
    ModelState.AddModelError("", "Invalid username or password");
    return View(login);
}

You could make roles and add to your users:

public ActionResult CreateRole(string roleName)
{
    var roleManager=HttpContext.GetOwinContext().GetUserManager<RoleManager<AppRole>>();

    if (!roleManager.RoleExists(roleName))
        roleManager.Create(new AppRole(roleName));
    // rest of code
} 

You could also add a role to a user, like this:

UserManager.AddToRole(UserManager.FindByName("username").Id, "roleName");

By using Authorize you could guard your actions or controllers:

[Authorize]
public ActionResult MySecretAction() {}

or

[Authorize(Roles = "Admin")]]
public ActionResult MySecretAction() {}

You can also install additional packages and configure them to meet your requirement like Microsoft.Owin.Security.Facebook or whichever you want.

Note: Don't forget to add relevant namespaces to your files:

using Microsoft.AspNet.Identity;
using Microsoft.Owin.Security;
using Microsoft.AspNet.Identity.Owin;
using Microsoft.AspNet.Identity.EntityFramework;
using Microsoft.Owin;
using Microsoft.Owin.Security.Cookies;
using Owin;

You could also see my other answers like this and this for advanced use of Identity.

Notepad++ Regular expression find and delete a line

Combining the best from all the answers

enter image description here

How to suppress "error TS2533: Object is possibly 'null' or 'undefined'"?

If you know the type will never be null or undefined, you should declare it as foo: Bar without the ?. Declaring a type with the ? Bar syntax means it could potentially be undefined, which is something you need to check for.

In other words, the compiler is doing exactly what you're asking it to. If you want it to be optional, you'll need to the check later.

500 internal server error, how to debug

Try writing all the errors to a file.

error_reporting(-1); // reports all errors
ini_set("display_errors", "1"); // shows all errors
ini_set("log_errors", 1);
ini_set("error_log", "/tmp/php-error.log");

Something like that.

Running an executable in Mac Terminal

Unix will only run commands if they are available on the system path, as you can view by the $PATH variable

echo $PATH

Executables located in directories that are not on the path cannot be run unless you specify their full location. So in your case, assuming the executable is in the current directory you are working with, then you can execute it as such

./my-exec

Where my-exec is the name of your program.

Sql query to insert datetime in SQL Server

A more language-independent choice for string literals is the international standard ISO 8601 format "YYYY-MM-DDThh:mm:ss". I used the SQL query below to test the format, and it does indeed work in all SQL languages in sys.syslanguages:

declare @sql nvarchar(4000)

declare @LangID smallint
declare @Alias sysname

declare @MaxLangID smallint
select @MaxLangID = max(langid) from sys.syslanguages

set @LangID = 0

while @LangID <= @MaxLangID
begin

    select @Alias = alias
    from sys.syslanguages
    where langid = @LangID

    if @Alias is not null
    begin

        begin try
            set @sql = N'declare @TestLang table (langdate datetime)
    set language ''' + @alias + N''';
    insert into @TestLang (langdate)
    values (''2012-06-18T10:34:09'')'
            print 'Testing ' + @Alias

            exec sp_executesql @sql
        end try
        begin catch
            print 'Error in language ' + @Alias
            print ERROR_MESSAGE()
        end catch
    end

    select @LangID = min(langid)
    from sys.syslanguages
    where langid > @LangID
end

According to the String Literal Date and Time Formats section in Microsoft TechNet, the standard ANSI Standard SQL date format "YYYY-MM-DD hh:mm:ss" is supposed to be "multi-language". However, using the same query, the ANSI format does not work in all SQL languages.

For example, in Danish, you will many errors like the following:

Error in language Danish The conversion of a varchar data type to a datetime data type resulted in an out-of-range value.

If you want to build a query in C# to run on SQL Server, and you need to pass a date in the ISO 8601 format, use the Sortable "s" format specifier:

string.Format("select convert(datetime2, '{0:s}'", DateTime.Now);

C++ printing boolean, what is displayed?

0 will get printed.

As in C++ true refers to 1 and false refers to 0.

In case, you want to print false instead of 0,then you have to sets the boolalpha format flag for the str stream.

When the boolalpha format flag is set, bool values are inserted/extracted by their textual representation: either true or false, instead of integral values.

#include <iostream>
int main()
{
  std::cout << std::boolalpha << false << std::endl;
}

output:

false

IDEONE

PHP date time greater than today

You are not comparing dates. You are comparing strings. In the world of string comparisons, 09/17/2015 > 01/02/2016 because 09 > 01. You need to either put your date in a comparable string format or compare DateTime objects which are comparable.

<?php
 $date_now = date("Y-m-d"); // this format is string comparable

if ($date_now > '2016-01-02') {
    echo 'greater than';
}else{
    echo 'Less than';
}

Demo

Or

<?php
 $date_now = new DateTime();
 $date2    = new DateTime("01/02/2016");

if ($date_now > $date2) {
    echo 'greater than';
}else{
    echo 'Less than';
}

Demo

What is the difference between Session.Abandon() and Session.Clear()

this code works and dont throw any exception:

Session.Abandon();  
Session["tempKey1"] = "tempValue1";

It's because when the Abandon method is called, the current Session object is queued for deletion but is not actually deleted until all of the script commands on the current page have been processed. This means that you can access variables stored in the Session object on the same page as the call to the Abandon method but not in any subsequent Web pages.

For example, in the following script, the third line prints the value Mary. This is because the Session object is not destroyed until the server has finished processing the script.

<% 
  Session.Abandon  
  Session("MyName") = "Mary" 
  Reponse.Write(Session("MyName")) 
%>

If you access the variable MyName on a subsequent Web page, it is empty. This is because MyName was destroyed with the previous Session object when the page containing the previous example finished processing.

from MSDN Session.Abandon

How to disable Google Chrome auto update?

For linux systems officially Google offers solution in Manage Chrome Browser updates (Linux)

and also I wrote a script below to make it for me:

   #!/bin/sh
   # stop chrome update from repository file
   sudo -s<<END
   touch /etc/default/google-chrome
   echo "repo_add_once=false" > /etc/default/google-chrome
   END

Also Disable Chromium Auto Update in Linux page states the same procedure.

Creating a list of dictionaries results in a list of copies of the same dictionary

You have misunderstood the Python list object. It is similar to a C pointer-array. It does not actually "copy" the object which you append to it. Instead, it just store a "pointer" to that object.

Try the following code:

>>> d={}
>>> dlist=[]
>>> for i in xrange(0,3):
    d['data']=i
    dlist.append(d)
    print(d)

{'data': 0}
{'data': 1}
{'data': 2}
>>> print(dlist)
[{'data': 2}, {'data': 2}, {'data': 2}]

So why is print(dlist) not the same as print(d)?

The following code shows you the reason:

>>> for i in dlist:
    print "the list item point to object:", id(i)

the list item point to object: 47472232
the list item point to object: 47472232
the list item point to object: 47472232

So you can see all the items in the dlist is actually pointing to the same dict object.

The real answer to this question will be to append the "copy" of the target item, by using d.copy().

>>> dlist=[]
>>> for i in xrange(0,3):
    d['data']=i
    dlist.append(d.copy())
    print(d)

{'data': 0}
{'data': 1}
{'data': 2}
>>> print dlist
[{'data': 0}, {'data': 1}, {'data': 2}]

Try the id() trick, you can see the list items actually point to completely different objects.

>>> for i in dlist:
    print "the list item points to object:", id(i)

the list item points to object: 33861576
the list item points to object: 47472520
the list item points to object: 47458120

Trying to handle "back" navigation button action in iOS

Swift

override func didMoveToParentViewController(parent: UIViewController?) {
    if parent == nil {
        //"Back pressed"
    }
}

How do I properly compare strings in C?

You can't compare arrays directly like this

array1==array2

You should compare them char-by-char; for this you can use a function and return a boolean (True:1, False:0) value. Then you can use it in the test condition of the while loop.

Try this:

#include <stdio.h>
int checker(char input[],char check[]);
int main()
{
    char input[40];
    char check[40];
    int i=0;
    printf("Hello!\nPlease enter a word or character:\n");
    scanf("%s",input);
    printf("I will now repeat this until you type it back to me.\n");
    scanf("%s",check);

    while (!checker(input,check))
    {
        printf("%s\n", input);
        scanf("%s",check);
    }

    printf("Good bye!");

    return 0;
}

int checker(char input[],char check[])
{
    int i,result=1;
    for(i=0; input[i]!='\0' || check[i]!='\0'; i++) {
        if(input[i] != check[i]) {
            result=0;
            break;
        }
    }
    return result;
}

The iOS Simulator deployment targets is set to 7.0, but the range of supported deployment target version for this platform is 8.0 to 12.1

in my case i have used both npm install and yarn install that is why i got this issue so to solve this i have removed package-lock.json and node_modules and then i did

yarn install
cd ios
pod install

it worked for me

How to push to History in React Router v4?

this.context.history.push will not work.

I managed to get push working like this:

static contextTypes = {
    router: PropTypes.object
}

handleSubmit(e) {
    e.preventDefault();

    if (this.props.auth.success) {
        this.context.router.history.push("/some/Path")
    }

}

CHECK constraint in MySQL is not working

Unfortunately MySQL does not support SQL check constraints. You can define them in your DDL query for compatibility reasons but they are just ignored.

There is a simple alternative

You can create BEFORE INSERT and BEFORE UPDATE triggers which either cause an error or set the field to its default value when the requirements of the data are not met.

Example for BEFORE INSERT working after MySQL 5.5

DELIMITER $$
CREATE TRIGGER `test_before_insert` BEFORE INSERT ON `Test`
FOR EACH ROW
BEGIN
    IF CHAR_LENGTH( NEW.ID ) < 4 THEN
        SIGNAL SQLSTATE '12345'
            SET MESSAGE_TEXT := 'check constraint on Test.ID failed';
    END IF;
END$$   
DELIMITER ;  

Prior to MySQL 5.5 you had to cause an error, e.g. call a undefined procedure.

In both cases this causes an implicit transaction rollback. MySQL does not allow the ROLLBACK statement itself within procedures and triggers.

If you don't want to rollback the transaction ( INSERT / UPDATE should pass even with a failed "check constraint" you can overwrite the value using SET NEW.ID = NULL which will set the id to the fields default value, doesn't really make sense for an id tho

Edit: Removed the stray quote.

Concerning the := operator:

Unlike =, the := operator is never interpreted as a comparison operator. This means you can use := in any valid SQL statement (not just in SET statements) to assign a value to a variable.

https://dev.mysql.com/doc/refman/5.6/en/assignment-operators.html

Concerning backtick identifier quotes:

The identifier quote character is the backtick (“`”)

If the ANSI_QUOTES SQL mode is enabled, it is also permissible to quote identifiers within double quotation marks

http://dev.mysql.com/doc/refman/5.6/en/identifiers.html

How can I list all cookies for the current page with Javascript?

For just quickly viewing the cookies on any particular page, I keep a favorites-bar "Cookies" shortcut with the URL set to:

javascript:window.alert(document.cookie.split(';').join(';\r\n'));

Python Library Path

You can also make additions to this path with the PYTHONPATH environment variable at runtime, in addition to:

import sys
sys.path.append('/home/user/python-libs')

What is the point of "final class" in Java?

One scenario where final is important, when you want to prevent inheritance of a class, for security reasons. This allows you to make sure that code you are running cannot be overridden by someone.

Another scenario is for optimization: I seem to remember that the Java compiler inlines some function calls from final classes. So, if you call a.x() and a is declared final, we know at compile-time what the code will be and can inline into the calling function. I have no idea whether this is actually done, but with final it is a possibility.

How to style child components from parent component's CSS file?

Update - Newest Way

Don't do it, if you can avoid it. As Devon Sans points out in the comments: This feature will most likely be deprecated.

#Update - Newer Way From Angular 4.3.0, all piercing css combinators were deprecated. Angular team introduced a new combinator ::ng-deep (still it is experimental and not the full and final way) as shown below,

DEMO : https://plnkr.co/edit/RBJIszu14o4svHLQt563?p=preview

styles: [
    `
     :host { color: red; }
     
     :host ::ng-deep parent {
       color:blue;
     }
     :host ::ng-deep child{
       color:orange;
     }
     :host ::ng-deep child.class1 {
       color:yellow;
     }
     :host ::ng-deep child.class2{
       color:pink;
     }
    `
],



template: `
      Angular2                                //red
      <parent>                                //blue
          <child></child>                     //orange
          <child class="class1"></child>      //yellow
          <child class="class2"></child>      //pink
      </parent>      
    `

# Old way

You can use encapsulation mode and/or piercing CSS combinators >>>, /deep/ and ::shadow

working example : http://plnkr.co/edit/1RBDGQ?p=preview

styles: [
    `
     :host { color: red; }
     :host >>> parent {
       color:blue;
     }
     :host >>> child{
       color:orange;
     }
     :host >>> child.class1 {
       color:yellow;
     }
     :host >>> child.class2{
       color:pink;
     }
    `
    ],

template: `
  Angular2                                //red
  <parent>                                //blue
      <child></child>                     //orange
      <child class="class1"></child>      //yellow
      <child class="class2"></child>      //pink
  </parent>      
`

How can I check if a key exists in a dictionary?

if key in array:
  # do something

Associative arrays are called dictionaries in Python and you can learn more about them in the stdtypes documentation.

Importing a Maven project into Eclipse from Git

I have a maven project with three submodules that is managed in git. I set them up in eclipse as follows:

  1. I registered the git repository with eclipse using EGit
  2. I imported the projects as existing Maven Projects
  3. For each project, I went Team | Share Project.

What is the largest Safe UDP Packet Size on the Internet

576 is the minimum maximum reassembly buffer size, i.e. each implementation must be able to reassemble packets of at least that size. See IETF RFC 1122 for details.

Sublime 3 - Set Key map for function Goto Definition

On a mac you have to set keybinding yourself. Simply go to

Sublime --> Preference --> Key Binding - User  

and input the following:

{ "keys": ["shift+command+m"], "command": "goto_definition" }

This will enable keybinding of Shift + Command + M to enable goto definition. You can set the keybinding to anything you would like of course.

How to do a PUT request with curl?

Using the -X flag with whatever HTTP verb you want:

curl -X PUT -d arg=val -d arg2=val2 localhost:8080

This example also uses the -d flag to provide arguments with your PUT request.

Running script upon login mac

tl;dr: use OSX's native process launcher and manager, launchd.

To do so, make a launchctl daemon. You'll have full control over all aspects of the script. You can run once or keep alive as a daemon. In most cases, this is the way to go.

  1. Create a .plist file according to the instructions in the Apple Dev docs here or more detail below.
  2. Place in ~/Library/LaunchAgents
  3. Log in (or run manually via launchctl load [filename.plist])

For more on launchd, the wikipedia article is quite good and describes the system and its advantages over other older systems.


Here's the specific plist file to run a script at login.

Updated 2017/09/25 for OSX El Capitan and newer (credit to José Messias Jr):

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
   <key>Label</key>
   <string>com.user.loginscript</string>
   <key>ProgramArguments</key>
   <array><string>/path/to/executable/script.sh</string></array>
   <key>RunAtLoad</key>
   <true/>
</dict>
</plist>

Replace the <string> after the Program key with your desired command (note that any script referenced by that command must be executable: chmod a+x /path/to/executable/script.sh to ensure it is for all users).

Save as ~/Library/LaunchAgents/com.user.loginscript.plist

Run launchctl load ~/Library/LaunchAgents/com.user.loginscript.plist and log out/in to test (or to test directly, run launchctl start com.user.loginscript)

Tail /var/log/system.log for error messages.

The key is that this is a User-specific launchd entry, so it will be run on login for the given user. System-specific launch daemons (placed in /Library/LaunchDaemons) are run on boot.

If you want a script to run on login for all users, I believe LoginHook is your only option, and that's probably the reason it exists.

Interface type check with Typescript

It's now possible, I just released an enhanced version of the TypeScript compiler that provides full reflection capabilities. You can instantiate classes from their metadata objects, retrieve metadata from class constructors and inspect interface/classes at runtime. You can check it out here

Usage example:

In one of your typescript files, create an interface and a class that implements it like the following:

interface MyInterface {
    doSomething(what: string): number;
}

class MyClass implements MyInterface {
    counter = 0;

    doSomething(what: string): number {
        console.log('Doing ' + what);
        return this.counter++;
    }
}

now let's print some the list of implemented interfaces.

for (let classInterface of MyClass.getClass().implements) {
    console.log('Implemented interface: ' + classInterface.name)
}

compile with reflec-ts and launch it:

$ node main.js
Implemented interface: MyInterface
Member name: counter - member kind: number
Member name: doSomething - member kind: function

See reflection.d.ts for Interface meta-type details.

UPDATE: You can find a full working example here

java.io.FileNotFoundException: /storage/emulated/0/New file.txt: open failed: EACCES (Permission denied)

If you are running in Android 29 then you have to use scoped storage or for now, you can bypass this issue by using:

android:requestLegacyExternalStorage="true"

in manifest in the application tag.

Maven version with a property

If you have a parent project you can set the version in the parent pom and in the children you can reference sibling libs with the ${project.version} or ${version} properties.

If you want to avoid to repeat the version of the parent in each children: you can do this:

<modelVersion>4.0.0</modelVersion>
<groupId>company</groupId>
<artifactId>build.parent</artifactId>
<version>${my.version}</version>
<packaging>pom</packaging>

<properties>
<my.version>1.1.2-SNAPSHOT</my.version>
</properties>

And then in your children pom you have to do:

    <parent>
      <artifactId>build.parent</artifactId>
      <groupId>company</groupId>
      <relativePath>../build.parent/pom.xml</relativePath>
      <version>${my.version}</version>
    </parent>

    <modelVersion>4.0.0</modelVersion>
    <groupId>company</groupId>
    <artifactId>artifact</artifactId>
    <packaging>eclipse-plugin</packaging>

    <dependencies>
        <dependency> 
           <groupId>company</groupId>
           <artifactId>otherartifact</artifactId>   
           <version>${my.version}</version>
or
           <version>${project.version}</version>
        </dependency>
    </dependencies>

hth

What's the difference between an Angular component and module

Angular Component

A component is one of the basic building blocks of an Angular app. An app can have more than one component. In a normal app, a component contains an HTML view page class file, a class file that controls the behaviour of the HTML page and the CSS/scss file to style your HTML view. A component can be created using @Component decorator that is part of @angular/core module.

import { Component } from '@angular/core';

and to create a component

@Component({selector: 'greet', template: 'Hello {{name}}!'})
class Greet {
  name: string = 'World';
}

To create a component or angular app here is the tutorial

Angular Module

An angular module is set of angular basic building blocks like component, directives, services etc. An app can have more than one module.

A module can be created using @NgModule decorator.

@NgModule({
  imports:      [ BrowserModule ],
  declarations: [ AppComponent ],
  bootstrap:    [ AppComponent ]
})
export class AppModule { }

Tomcat Server Error - Port 8080 already in use

You can solve this in two steps:

STEP 1: Open the Command prompt and type netstat -a -o -f and press enter (the above command will show all the processes running on your machine) https://i.stack.imgur.com/m66JN.png

STEP 2: Type TASKILL /F /PID 4036 (where F stands for force and PID stands for parent Id and 4036 stands for process id of 8080, here I am using some random number) https://i.stack.imgur.com/Co5Tg.png

Few times when you are trying to kill process it will throw an exception telling that access is denied as shown in the above screenshot, at that point of time you are supposed to open command prompt as run as administrator https://i.stack.imgur.com/JwZTv.png

Then come back to eclipse clean the project and then try to run the project

*ngIf else if in template

Another alternative is to nest conditions

<ng-container *ngIf="foo === 1;else second"></ng-container>
<ng-template #second>
    <ng-container *ngIf="foo === 2;else third"></ng-container>
</ng-template>
<ng-template #third></ng-template>

Array vs. Object efficiency in JavaScript

I tried to take this to the next dimension, literally.

Given a 2 dimensional array, in which the x and y axes are always the same length, is it faster to:

a) look up the cell by creating a two dimensional array and looking up the first index, followed by the second index, i.e:

var arr=[][]    
var cell=[x][y]    

or

b) create an object with a string representation of the x and y coordinates, and then do a single lookup on that obj, i.e:

var obj={}    
var cell = obj['x,y']    

Result:
Turns out that it's much faster to do two numeric index lookups on the arrays, than one property lookup on the object.

Results here:

http://jsperf.com/arr-vs-obj-lookup-2

How to Reload ReCaptcha using JavaScript?

Important: Version 1.0 of the reCAPTCHA API is no longer supported, please upgrade to Version 2.0.

You can use grecaptcha.reset(); to reset the captcha.

Source : https://developers.google.com/recaptcha/docs/verify#api-request

How to format numbers?

Due to the bugs found by JasperV — good points! — I have rewritten my old code. I guess I only ever used this for positive values with two decimal places.

Depending on what you are trying to achieve, you may want rounding or not, so here are two versions split across that divide.

First up, with rounding.

I've introduced the toFixed() method as it better handles rounding to specific decimal places accurately and is well support. It does slow things down however.

This version still detaches the decimal, but using a different method than before. The w|0 part removes the decimal. For more information on that, this is a good answer. This then leaves the remaining integer, stores it in k and then subtracts it again from the original number, leaving the decimal by itself.

Also, if we're to take negative numbers into account, we need to while loop (skipping three digits) until we hit b. This has been calculated to be 1 when dealing with negative numbers to avoid putting something like -,100.00

The rest of the loop is the same as before.

function formatThousandsWithRounding(n, dp){
  var w = n.toFixed(dp), k = w|0, b = n < 0 ? 1 : 0,
      u = Math.abs(w-k), d = (''+u.toFixed(dp)).substr(2, dp),
      s = ''+k, i = s.length, r = '';
  while ( (i-=3) > b ) { r = ',' + s.substr(i, 3) + r; }
  return s.substr(0, i + 3) + r + (d ? '.'+d: '');
};

In the snippet below you can edit the numbers to test yourself.

_x000D_
_x000D_
function formatThousandsWithRounding(n, dp){_x000D_
  var w = n.toFixed(dp), k = w|0, b = n < 0 ? 1 : 0,_x000D_
      u = Math.abs(w-k), d = (''+u.toFixed(dp)).substr(2, dp),_x000D_
      s = ''+k, i = s.length, r = '';_x000D_
  while ( (i-=3) > b ) { r = ',' + s.substr(i, 3) + r; }_x000D_
  return s.substr(0, i + 3) + r + (d ? '.'+d: '');_x000D_
};_x000D_
_x000D_
var dp;_x000D_
var createInput = function(v){_x000D_
  var inp = jQuery('<input class="input" />').val(v);_x000D_
  var eql = jQuery('<span>&nbsp;=&nbsp;</span>');_x000D_
  var out = jQuery('<div class="output" />').css('display', 'inline-block');_x000D_
  var row = jQuery('<div class="row" />');_x000D_
  row.append(inp).append(eql).append(out);_x000D_
  inp.keyup(function(){_x000D_
    out.text(formatThousandsWithRounding(Number(inp.val()), Number(dp.val())));_x000D_
  });_x000D_
  inp.keyup();_x000D_
  jQuery('body').append(row);_x000D_
  return inp;_x000D_
};_x000D_
_x000D_
jQuery(function(){_x000D_
  var numbers = [_x000D_
    0, 99.999, -1000, -1000000, 1000000.42, -1000000.57, -1000000.999_x000D_
  ], inputs = $();_x000D_
  dp = jQuery('#dp');_x000D_
  for ( var i=0; i<numbers.length; i++ ) {_x000D_
    inputs = inputs.add(createInput(numbers[i]));_x000D_
  }_x000D_
  dp.on('input change', function(){_x000D_
    inputs.keyup();_x000D_
  });_x000D_
});
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<input id="dp" type="range" min="0" max="5" step="1" value="2" title="number of decimal places?" />
_x000D_
_x000D_
_x000D_

Now the other version, without rounding.

This takes a different route and attempts to avoid mathematical calculation (as this can introduce rounding, or rounding errors). If you don't want rounding, then you are only dealing with things as a string i.e. 1000.999 converted to two decimal places will only ever be 1000.99 and not 1001.00.

This method avoids using .split() and RegExp() however, both of which are very slow in comparison. And whilst I learned something new from Michael's answer about toLocaleString, I also was surprised to learn that it is — by quite a way — the slowest method out of them all (at least in Firefox and Chrome; Mac OSX).

Using lastIndexOf() we find the possibly existent decimal point, and from there everything else is pretty much the same. Save for the padding with extra 0s where needed. This code is limited to 5 decimal places. Out of my test this was the faster method.

var formatThousandsNoRounding = function(n, dp){
  var e = '', s = e+n, l = s.length, b = n < 0 ? 1 : 0,
      i = s.lastIndexOf('.'), j = i == -1 ? l : i,
      r = e, d = s.substr(j+1, dp);
  while ( (j-=3) > b ) { r = ',' + s.substr(j, 3) + r; }
  return s.substr(0, j + 3) + r + 
    (dp ? '.' + d + ( d.length < dp ? 
        ('00000').substr(0, dp - d.length):e):e);
};

_x000D_
_x000D_
var formatThousandsNoRounding = function(n, dp){_x000D_
  var e = '', s = e+n, l = s.length, b = n < 0 ? 1 : 0,_x000D_
      i = s.lastIndexOf('.'), j = i == -1 ? l : i,_x000D_
      r = e, d = s.substr(j+1, dp);_x000D_
  while ( (j-=3) > b ) { r = ',' + s.substr(j, 3) + r; }_x000D_
  return s.substr(0, j + 3) + r + _x000D_
   (dp ? '.' + d + ( d.length < dp ? _x000D_
     ('00000').substr(0, dp - d.length):e):e);_x000D_
};_x000D_
_x000D_
var dp;_x000D_
var createInput = function(v){_x000D_
  var inp = jQuery('<input class="input" />').val(v);_x000D_
  var eql = jQuery('<span>&nbsp;=&nbsp;</span>');_x000D_
  var out = jQuery('<div class="output" />').css('display', 'inline-block');_x000D_
  var row = jQuery('<div class="row" />');_x000D_
  row.append(inp).append(eql).append(out);_x000D_
  inp.keyup(function(){_x000D_
    out.text(formatThousandsNoRounding(Number(inp.val()), Number(dp.val())));_x000D_
  });_x000D_
  inp.keyup();_x000D_
  jQuery('body').append(row);_x000D_
  return inp;_x000D_
};_x000D_
_x000D_
jQuery(function(){_x000D_
  var numbers = [_x000D_
    0, 99.999, -1000, -1000000, 1000000.42, -1000000.57, -1000000.999_x000D_
  ], inputs = $();_x000D_
  dp = jQuery('#dp');_x000D_
  for ( var i=0; i<numbers.length; i++ ) {_x000D_
    inputs = inputs.add(createInput(numbers[i]));_x000D_
  }_x000D_
  dp.on('input change', function(){_x000D_
    inputs.keyup();_x000D_
  });_x000D_
});
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<input id="dp" type="range" min="0" max="5" step="1" value="2" title="number of decimal places?" />
_x000D_
_x000D_
_x000D_

I'll update with an in-page snippet demo shortly, but for now here is a fiddle:

https://jsfiddle.net/bv2ort0a/2/



Old Method

Why use RegExp for this? — don't use a hammer when a toothpick will do i.e. use string manipulation:

var formatThousands = function(n, dp){
  var s = ''+(Math.floor(n)), d = n % 1, i = s.length, r = '';
  while ( (i -= 3) > 0 ) { r = ',' + s.substr(i, 3) + r; }
  return s.substr(0, i + 3) + r + 
    (d ? '.' + Math.round(d * Math.pow(10, dp || 2)) : '');
};

walk through

formatThousands( 1000000.42 );

First strip off decimal:

s = '1000000', d = ~ 0.42

Work backwards from the end of the string:

',' + '000'
',' + '000' + ',000'

Finalise by adding the leftover prefix and the decimal suffix (with rounding to dp no. decimal points):

'1' + ',000,000' + '.42'

fiddlesticks

http://jsfiddle.net/XC3sS/

What does the 'b' character do in front of a string literal?

Here's an example where the absence of b would throw a TypeError exception in Python 3.x

>>> f=open("new", "wb")
>>> f.write("Hello Python!")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'str' does not support the buffer interface

Adding a b prefix would fix the problem.

angular2: how to copy object into another object

Object.assign will only work in single level of object reference.

To do a copy in any depth use as below:

let x = {'a':'a','b':{'c':'c'}};
let y = JSON.parse(JSON.stringify(x));

If want to use any library instead then go with the loadash.js library.

ERROR Android emulator gets killed

Please check your free space on your disk also. I had a same problem and finally I got I need to free up space to fix this.

Efficient way to return a std::vector in c++

   vector<string> func1() const
   {
      vector<string> parts;
      return vector<string>(parts.begin(),parts.end()) ;
   } 

How to deploy a Java Web Application (.war) on tomcat?

As others pointed out, the most straightforward way to deploy a WAR is to copy it to the webapps of the Tomcat install. Another option would be to use the manager application if it is installed (this is not always the case), if it's properly configured (i.e. if you have the credentials of a user assigned to the appropriate group) and if it you can access it over an insecure network like Internet (but this is very unlikely and you didn't mention any VPN access). So this leaves you with the webappdirectory.

Now, if Tomcat is installed and running on bilgin.ath.cx (as this is the machine where you uploaded the files), I noticed that Apache is listening to port 80 on that machien so I would bet that Tomcat is not directly exposed and that requests have to go through Apache. In that case, I think that deploying a new webapp and making it visible to the Internet will involve the edit of Apache configuration files (mod_jk?, mod_proxy?). You should either give us more details or discuss this with your hosting provider.

Update: As expected, the bilgin.ath.cx is using Apache Tomcat + Apache HTTPD + mod_jk. The configuration usually involves two files: the worker.properties file to configure the workers and the httpd.conf for Apache. Now, without seeing the current configuration, it's not easy to give a definitive answer but, basically, you may have to add a JkMount directive in Apache httpd.conf for your new webapp1. Refer to the mod_jk documentation, it has a simple configuration example. Note that modifying httpd.conf will require access to (obviously) and proper rights and that you'll have to restart Apache after the modifications.

1 I don't think you'll need to define a new worker if you are deploying to an already used Tomcat instance, especially if this sounds like Chinese for you :)

JS file gets a net::ERR_ABORTED 404 (Not Found)

As mentionned in comments: you need a way to send your static files to the client. This can be achieved with a reverse proxy like Nginx, or simply using express.static().

Put all your "static" (css, js, images) files in a folder dedicated to it, different from where you put your "views" (html files in your case). I'll call it static for the example. Once it's done, add this line in your server code:

app.use("/static", express.static('./static/'));

This will effectively serve every file in your "static" folder via the /static route.

Querying your index.js file in the client thus becomes:

<script src="static/index.js"></script>

List<object>.RemoveAll - How to create an appropriate Predicate

Little bit off topic but say i want to remove all 2s from a list. Here's a very elegant way to do that.

void RemoveAll<T>(T item,List<T> list)
{
    while(list.Contains(item)) list.Remove(item);
}

With predicate:

void RemoveAll<T>(Func<T,bool> predicate,List<T> list)
{
    while(list.Any(predicate)) list.Remove(list.First(predicate));
}

+1 only to encourage you to leave your answer here for learning purposes. You're also right about it being off-topic, but I won't ding you for that because of there is significant value in leaving your examples here, again, strictly for learning purposes. I'm posting this response as an edit because posting it as a series of comments would be unruly.

Though your examples are short & compact, neither is elegant in terms of efficiency; the first is bad at O(n2), the second, absolutely abysmal at O(n3). Algorithmic efficiency of O(n2) is bad and should be avoided whenever possible, especially in general-purpose code; efficiency of O(n3) is horrible and should be avoided in all cases except when you know n will always be very small. Some might fling out their "premature optimization is the root of all evil" battle axes, but they do so naïvely because they do not truly understand the consequences of quadratic growth since they've never coded algorithms that have to process large datasets. As a result, their small-dataset-handling algorithms just run generally slower than they could, and they have no idea that they could run faster. The difference between an efficient algorithm and an inefficient algorithm is often subtle, but the performance difference can be dramatic. The key to understanding the performance of your algorithm is to understand the performance characteristics of the primitives you choose to use.

In your first example, list.Contains() and Remove() are both O(n), so a while() loop with one in the predicate & the other in the body is O(n2); well, technically O(m*n), but it approaches O(n2) as the number of elements being removed (m) approaches the length of the list (n).

Your second example is even worse: O(n3), because for every time you call Remove(), you also call First(predicate), which is also O(n). Think about it: Any(predicate) loops over the list looking for any element for which predicate() returns true. Once it finds the first such element, it returns true. In the body of the while() loop, you then call list.First(predicate) which loops over the list a second time looking for the same element that had already been found by list.Any(predicate). Once First() has found it, it returns that element which is passed to list.Remove(), which loops over the list a third time to yet once again find that same element that was previously found by Any() and First(), in order to finally remove it. Once removed, the whole process starts over at the beginning with a slightly shorter list, doing all the looping over and over and over again starting at the beginning every time until finally no more elements matching the predicate remain. So the performance of your second example is O(m*m*n), or O(n3) as m approaches n.

Your best bet for removing all items from a list that match some predicate is to use the generic list's own List<T>.RemoveAll(predicate) method, which is O(n) as long as your predicate is O(1). A for() loop technique that passes over the list only once, calling list.RemoveAt() for each element to be removed, may seem to be O(n) since it appears to pass over the loop only once. Such a solution is more efficient than your first example, but only by a constant factor, which in terms of algorithmic efficiency is negligible. Even a for() loop implementation is O(m*n) since each call to Remove() is O(n). Since the for() loop itself is O(n), and it calls Remove() m times, the for() loop's growth is O(n2) as m approaches n.

What MIME type should I use for CSV?

For anyone struggling with Google API mimeType for *.csv files. I have found the list of MIME types for google api docs files (look at snipped result)

_x000D_
_x000D_
<table border="1"><thead><tr><th>Google Doc Format</th><th>Conversion Format</th><th>Corresponding MIME type</th></tr></thead><tbody><tr><td>Documents</td><td>HTML</td><td>text/html</td></tr><tr></tr><tr><td></td><td>HTML (zipped)</td><td>application/zip</td></tr><tr><td></td><td>Plain text</td><td>text/plain</td></tr><tr><td></td><td>Rich text</td><td>application/rtf</td></tr><tr><td></td><td>Open Office doc</td><td>application/vnd.oasis.opendocument.text</td></tr><tr><td></td><td>PDF</td><td>application/pdf</td></tr><tr><td></td><td>MS Word document</td><td>application/vnd.openxmlformats-officedocument.wordprocessingml.document</td></tr><tr><td></td><td>EPUB</td><td>application/epub+zip</td></tr><tr><td>Spreadsheets</td><td>MS Excel</td><td>application/vnd.openxmlformats-officedocument.spreadsheetml.sheet</td></tr><tr><td></td><td>Open Office sheet</td><td>application/x-vnd.oasis.opendocument.spreadsheet</td></tr><tr><td></td><td>PDF</td><td>application/pdf</td></tr><tr><td></td><td>CSV (first sheet only)</td><td>text/csv</td></tr><tr><td></td><td>TSV (first sheet only)</td><td>text/tab-separated-values</td></tr><tr><td></td><td>HTML (zipped)</td><td>application/zip</td></tr><tr></tr><tr><td>Drawings</td><td>JPEG</td><td>image/jpeg</td></tr><tr><td></td><td>PNG</td><td>image/png</td></tr><tr><td></td><td>SVG</td><td>image/svg+xml</td></tr><tr><td></td><td>PDF</td><td>application/pdf</td></tr><tr><td>Presentations</td><td>MS PowerPoint</td><td>application/vnd.openxmlformats-officedocument.presentationml.presentation</td></tr><tr><td></td><td>Open Office presentation</td><td>application/vnd.oasis.opendocument.presentation</td></tr><tr></tr><tr><td></td><td>PDF</td><td>application/pdf</td></tr><tr><td></td><td>Plain text</td><td>text/plain</td></tr><tr><td>Apps Scripts</td><td>JSON</td><td>application/vnd.google-apps.script+json</td></tr></tbody></table>
_x000D_
_x000D_
_x000D_

Source here: https://developers.google.com/drive/v3/web/manage-downloads#downloading_google_documents the table under: "Google Doc formats and supported export MIME types map to each other as follows"

There is also another list

_x000D_
_x000D_
<table border="1"><thead><tr><th>MIME Type</th><th>Description</th></tr></thead><tbody><tr><td><code><span>application/vnd.<wbr>google-apps.<wbr>audio</span></code></td><td></td></tr><tr><td><code><span>application/vnd.<wbr>google-apps.<wbr>document</span></code></td><td>Google Docs</td></tr><tr><td><code><span>application/vnd.<wbr>google-apps.<wbr>drawing</span></code></td><td>Google Drawing</td></tr><tr><td><code><span>application/vnd.<wbr>google-apps.<wbr>file</span></code></td><td>Google Drive file</td></tr><tr><td><code><span>application/vnd.<wbr>google-apps.<wbr>folder</span></code></td><td>Google Drive folder</td></tr><tr><td><code><span>application/vnd.<wbr>google-apps.<wbr>form</span></code></td><td>Google Forms</td></tr><tr><td><code><span>application/vnd.<wbr>google-apps.<wbr>fusiontable</span></code></td><td>Google Fusion Tables</td></tr><tr><td><code><span>application/vnd.<wbr>google-apps.<wbr>map</span></code></td><td>Google My Maps</td></tr><tr><td><code><span>application/vnd.<wbr>google-apps.<wbr>photo</span></code></td><td></td></tr><tr><td><code><span>application/vnd.<wbr>google-apps.<wbr>presentation</span></code></td><td>Google Slides</td></tr><tr><td><code><span>application/vnd.<wbr>google-apps.<wbr>script</span></code></td><td>Google Apps Scripts</td></tr><tr><td><code><span>application/vnd.<wbr>google-apps.<wbr>site</span></code></td><td>Google Sites</td></tr><tr><td><code><span>application/vnd.<wbr>google-apps.<wbr>spreadsheet</span></code></td><td>Google Sheets</td></tr><tr><td><code><span>application/vnd.<wbr>google-apps.<wbr>unknown</span></code></td><td></td></tr><tr><td><code><span>application/vnd.<wbr>google-apps.<wbr>video</span></code></td><td></td></tr><tr><td><code><span>application/vnd.<wbr>google-apps.<wbr>drive-sdk</span></code></td><td>3rd party shortcut</td></tr></tbody></table>
_x000D_
_x000D_
_x000D_

Source here: https://developers.google.com/drive/v3/web/mime-types

But the first one was more helpful for my use case..

Happy coding ;)

Clear screen in shell

If you are using linux terminal to access python, then cntrl+l is the best solution to clear screen

How to compare a local git branch with its remote branch?

In android studio, it is possible to see the difference between branches using graphical interface. Select your remote branch and and "Compare with current" from the list. From then you can select the files tab to see if there are any files that have content difference between both branches. If no file is seen, then both branches are up-to-date with each other.

Why isn't .ico file defined when setting window's icon?

Both codes are working fine with me on python 3.7..... hope will work for u as well

import tkinter as tk
m=tk.Tk()
m.iconbitmap("myfavicon.ico")
m.title("SALAH Tutorials")
m.mainloop()

and do not forget to keep "myfavicon.ico" in the same folder where your project script file is present

Another method

from tkinter import *
m=Tk()
m.iconbitmap("myfavicon.ico")
m.title("SALAH Tutorials")
m.mainloop()

[*NOTE:- python version-3 works with tkinter and below version-3 i.e version-2 works with Tkinter]

g++ ld: symbol(s) not found for architecture x86_64

finally solved my problem.

I created a new project in XCode with the sources and changed the C++ Standard Library from the default libc++ to libstdc++ as in this and this.

A function to convert null to string

You can use Convert.ToString((object)value). You need to cast your value to an object first, otherwise the conversion will result in a null.

using System;

public class Program
{
    public static void Main()
    {
        string format = "    Convert.ToString({0,-20}) == null? {1,-5},  == empty? {2,-5}";
        object nullObject = null;
        string nullString = null;

        string convertedString = Convert.ToString(nullObject);
        Console.WriteLine(format, "nullObject", convertedString == null, convertedString == "");

        convertedString = Convert.ToString(nullString);
        Console.WriteLine(format, "nullString", convertedString == null, convertedString == "");

        convertedString = Convert.ToString((object)nullString);
        Console.WriteLine(format, "(object)nullString", convertedString == null, convertedString == "");

    }
}

Gives:

Convert.ToString(nullObject          ) == null? False,  == empty? True 
Convert.ToString(nullString          ) == null? True ,  == empty? False
Convert.ToString((object)nullString  ) == null? False,  == empty? True

If you pass a System.DBNull.Value to Convert.ToString() it will be converted to an empty string too.

Groovy / grails how to determine a data type?

To determine the class of an object simply call:

someObject.getClass()

You can abbreviate this to someObject.class in most cases. However, if you use this on a Map it will try to retrieve the value with key 'class'. Because of this, I always use getClass() even though it's a little longer.

If you want to check if an object implements a particular interface or extends a particular class (e.g. Date) use:

(somObject instanceof Date)

or to check if the class of an object is exactly a particular class (not a subclass of it), use:

(somObject.getClass() == Date)

How to clear all data in a listBox?

In C# Core DataSource does not exist, but this work fine:

listbox.ItemsSource = null;
listbox.Items.Clear();

Jenkins Slave port number for firewall

We had a similar situation, but in our case Infosec agreed to allow any to 1, so we didnt had to fix the slave port, rather fixing the master to high level JNLP port 49187 worked ("Configure Global Security" -> "TCP port for JNLP slave agents").

TCP
49187 - Fixed jnlp port
8080 - jenkins http port

Other ports needed to launch slave as a windows service

TCP
135 
139 
445

UDP
137
138

How to make the first option of <select> selected with jQuery

// remove "selected" from any options that might already be selected
$('#target option[selected="selected"]').each(
    function() {
        $(this).removeAttr('selected');
    }
);


// mark the first option as selected
$("#target option:first").attr('selected','selected');

Pass variables from servlet to jsp

This is an servlet code which contain a string variable a. the value for a is getting from an html page with form. then set the variable into the request object. then pass it to jsp using forward and requestdispatcher methods.

String a=req.getParameter("username");
req.setAttribute("name", a);
RequestDispatcher rd=req.getRequestDispatcher("/login.jsp");
rd.forward(req, resp);

in jsp follow these steps shown below in the program

<%String name=(String)request.getAttribute("name");
out.print("your name"+name);%>

What is lazy loading in Hibernate?

Lazy loading is a design pattern commonly used in computer programming to defer initialization of an object until the point at which it is needed. It can contribute to efficiency in the program's operation if properly and appropriately used

Wikipedia

Link of Lazy Loading from hibernate.org

How to determine the current iPhone/device model?

Dealing with c structs is painful in swift. Especially if they have some kind of c arrays in it. Here is my solution: Continue to use objective-c. Just create a wrapper objective-c class that does this job and then use that class in swift. Here is a sample class that does exactly this:

@interface DeviceInfo : NSObject

+ (NSString *)model;

@end

#import "DeviceInfo.h"
#import <sys/utsname.h>

@implementation DeviceInfo

+ (NSString *)model
{
    struct utsname systemInfo;
    uname(&systemInfo);

    return [NSString stringWithCString: systemInfo.machine encoding: NSUTF8StringEncoding];
}

@end

In swift side:

let deviceModel = DeviceInfo.model()

Spring @PropertySource using YAML

This is not an answer to the original question, but an alternative solution for a need to have a different configuration in a test...

Instead of @PropertySource you can use -Dspring.config.additional-location=classpath:application-tests.yml.

Be aware, that suffix tests does not mean profile...

In that one YAML file one can specify multiple profiles, that can kind of inherit from each other, read more here - Property resolving for multiple Spring profiles (yaml configuration)

Then, you can specify in your test, that active profiles (using @ActiveProfiles("profile1,profile2")) are profile1,profile2 where profile2 will simply override (some, one does not need to override all) properties from profile1.

Function pointer as parameter

The correct way to do this is:

typedef void (*callback_function)(void); // type for conciseness

callback_function disconnectFunc; // variable to store function pointer type

void D::setDisconnectFunc(callback_function pFunc)
{
    disconnectFunc = pFunc; // store
}

void D::disconnected()
{
    disconnectFunc(); // call
    connected = false;
}

How to make UIButton's text alignment center? Using IB

For ios 8 and Swift

btn.titleLabel.textAlignment = NSTextAlignment.Center

or

btn.titleLabel.textAlignment = .Center

How can I produce an effect similar to the iOS 7 blur view?

This is a solution that you can see in the vidios of the WWDC. You have to do a Gaussian Blur, so the first thing you have to do is to add a new .m and .h file with the code i'm writing here, then you have to make and screen shoot, use the desired effect and add it to your view, then your UITable UIView or what ever has to be transparent, you can play with applyBlurWithRadius, to archive the desired effect, this call works with any UIImage.

At the end the blured image will be the background and the rest of the controls above has to be transparent.

For this to work you have to add the next libraries:

Acelerate.framework,UIKit.framework,CoreGraphics.framework

I hope you like it.

Happy coding.

    //Screen capture.
    UIGraphicsBeginImageContext(self.view.bounds.size);

    CGContextRef c = UIGraphicsGetCurrentContext();
    CGContextTranslateCTM(c, 0, 0);
    [self.view.layer renderInContext:c];

    UIImage* viewImage = UIGraphicsGetImageFromCurrentImageContext();
    viewImage = [viewImage applyLightEffect];

    UIGraphicsEndImageContext();

    //.h FILE
    #import <UIKit/UIKit.h>

    @interface UIImage (ImageEffects)

   - (UIImage *)applyLightEffect;
   - (UIImage *)applyExtraLightEffect;
   - (UIImage *)applyDarkEffect;
   - (UIImage *)applyTintEffectWithColor:(UIColor *)tintColor;

   - (UIImage *)applyBlurWithRadius:(CGFloat)blurRadius tintColor:(UIColor *)tintColor saturationDeltaFactor:(CGFloat)saturationDeltaFactor maskImage:(UIImage *)maskImage;

   @end

    //.m FILE
    #import "cGaussianEffect.h"
    #import <Accelerate/Accelerate.h>
    #import <float.h>


     @implementation UIImage (ImageEffects)


    - (UIImage *)applyLightEffect
    {
        UIColor *tintColor = [UIColor colorWithWhite:1.0 alpha:0.3];
        return [self applyBlurWithRadius:1 tintColor:tintColor saturationDeltaFactor:1.8 maskImage:nil];
    }


    - (UIImage *)applyExtraLightEffect
    {
        UIColor *tintColor = [UIColor colorWithWhite:0.97 alpha:0.82];
        return [self applyBlurWithRadius:1 tintColor:tintColor saturationDeltaFactor:1.8 maskImage:nil];
    }


    - (UIImage *)applyDarkEffect
    {
        UIColor *tintColor = [UIColor colorWithWhite:0.11 alpha:0.73];
        return [self applyBlurWithRadius:1 tintColor:tintColor saturationDeltaFactor:1.8 maskImage:nil];
    }


    - (UIImage *)applyTintEffectWithColor:(UIColor *)tintColor
    {
        const CGFloat EffectColorAlpha = 0.6;
        UIColor *effectColor = tintColor;
        int componentCount = CGColorGetNumberOfComponents(tintColor.CGColor);
        if (componentCount == 2) {
            CGFloat b;
            if ([tintColor getWhite:&b alpha:NULL]) {
                effectColor = [UIColor colorWithWhite:b alpha:EffectColorAlpha];
            }
        }
        else {
            CGFloat r, g, b;
            if ([tintColor getRed:&r green:&g blue:&b alpha:NULL]) {
                effectColor = [UIColor colorWithRed:r green:g blue:b alpha:EffectColorAlpha];
            }
        }
        return [self applyBlurWithRadius:10 tintColor:effectColor saturationDeltaFactor:-1.0 maskImage:nil];
    }


    - (UIImage *)applyBlurWithRadius:(CGFloat)blurRadius tintColor:(UIColor *)tintColor saturationDeltaFactor:(CGFloat)saturationDeltaFactor maskImage:(UIImage *)maskImage
    {
        if (self.size.width < 1 || self.size.height < 1) {
            NSLog (@"*** error: invalid size: (%.2f x %.2f). Both dimensions must be >= 1: %@", self.size.width, self.size.height, self);
            return nil;
        }
        if (!self.CGImage) {
            NSLog (@"*** error: image must be backed by a CGImage: %@", self);
            return nil;
        }
        if (maskImage && !maskImage.CGImage) {
            NSLog (@"*** error: maskImage must be backed by a CGImage: %@", maskImage);
            return nil;
        }

        CGRect imageRect = { CGPointZero, self.size };
        UIImage *effectImage = self;

        BOOL hasBlur = blurRadius > __FLT_EPSILON__;
        BOOL hasSaturationChange = fabs(saturationDeltaFactor - 1.) > __FLT_EPSILON__;
        if (hasBlur || hasSaturationChange) {
            UIGraphicsBeginImageContextWithOptions(self.size, NO, [[UIScreen mainScreen] scale]);
            CGContextRef effectInContext = UIGraphicsGetCurrentContext();
            CGContextScaleCTM(effectInContext, 1.0, -1.0);
            CGContextTranslateCTM(effectInContext, 0, -self.size.height);
            CGContextDrawImage(effectInContext, imageRect, self.CGImage);

            vImage_Buffer effectInBuffer;
            effectInBuffer.data     = CGBitmapContextGetData(effectInContext);
            effectInBuffer.width    = CGBitmapContextGetWidth(effectInContext);
            effectInBuffer.height   = CGBitmapContextGetHeight(effectInContext);
            effectInBuffer.rowBytes = CGBitmapContextGetBytesPerRow(effectInContext);

            UIGraphicsBeginImageContextWithOptions(self.size, NO, [[UIScreen mainScreen] scale]);
            CGContextRef effectOutContext = UIGraphicsGetCurrentContext();
            vImage_Buffer effectOutBuffer;
            effectOutBuffer.data     = CGBitmapContextGetData(effectOutContext);
            effectOutBuffer.width    = CGBitmapContextGetWidth(effectOutContext);
            effectOutBuffer.height   = CGBitmapContextGetHeight(effectOutContext);
            effectOutBuffer.rowBytes = CGBitmapContextGetBytesPerRow(effectOutContext);

            if (hasBlur) {
                CGFloat inputRadius = blurRadius * [[UIScreen mainScreen] scale];
                NSUInteger radius = floor(inputRadius * 3. * sqrt(2 * M_PI) / 4 + 0.5);
                if (radius % 2 != 1) {
                    radius += 1;
                }
                vImageBoxConvolve_ARGB8888(&effectInBuffer, &effectOutBuffer, NULL, 0, 0, radius, radius, 0, kvImageEdgeExtend);
                vImageBoxConvolve_ARGB8888(&effectOutBuffer, &effectInBuffer, NULL, 0, 0, radius, radius, 0, kvImageEdgeExtend);
                vImageBoxConvolve_ARGB8888(&effectInBuffer, &effectOutBuffer, NULL, 0, 0, radius, radius, 0, kvImageEdgeExtend);
            }
            BOOL effectImageBuffersAreSwapped = NO;
            if (hasSaturationChange) {
                CGFloat s = saturationDeltaFactor;
                CGFloat floatingPointSaturationMatrix[] = {
                    0.0722 + 0.9278 * s,  0.0722 - 0.0722 * s,  0.0722 - 0.0722 * s,  0,
                    0.7152 - 0.7152 * s,  0.7152 + 0.2848 * s,  0.7152 - 0.7152 * s,  0,
                    0.2126 - 0.2126 * s,  0.2126 - 0.2126 * s,  0.2126 + 0.7873 * s,  0,
                                  0,                    0,                    0,  1,
                };
                const int32_t divisor = 256;
                NSUInteger matrixSize = sizeof(floatingPointSaturationMatrix)/sizeof(floatingPointSaturationMatrix[0]);
                int16_t saturationMatrix[matrixSize];
                for (NSUInteger i = 0; i < matrixSize; ++i) {
                    saturationMatrix[i] = (int16_t)roundf(floatingPointSaturationMatrix[i] * divisor);
                }
                if (hasBlur) {
                    vImageMatrixMultiply_ARGB8888(&effectOutBuffer, &effectInBuffer, saturationMatrix, divisor, NULL, NULL, kvImageNoFlags);
                    effectImageBuffersAreSwapped = YES;
                }
                else {
                    vImageMatrixMultiply_ARGB8888(&effectInBuffer, &effectOutBuffer, saturationMatrix, divisor, NULL, NULL, kvImageNoFlags);
                }
            }
            if (!effectImageBuffersAreSwapped)
                effectImage = UIGraphicsGetImageFromCurrentImageContext();
            UIGraphicsEndImageContext();

            if (effectImageBuffersAreSwapped)
                effectImage = UIGraphicsGetImageFromCurrentImageContext();
            UIGraphicsEndImageContext();
        }

        UIGraphicsBeginImageContextWithOptions(self.size, NO, [[UIScreen mainScreen] scale]);
        CGContextRef outputContext = UIGraphicsGetCurrentContext();
        CGContextScaleCTM(outputContext, 1.0, -1.0);
        CGContextTranslateCTM(outputContext, 0, -self.size.height);

        CGContextDrawImage(outputContext, imageRect, self.CGImage);

        if (hasBlur) {
            CGContextSaveGState(outputContext);
            if (maskImage) {
                CGContextClipToMask(outputContext, imageRect, maskImage.CGImage);
            }
            CGContextDrawImage(outputContext, imageRect, effectImage.CGImage);
            CGContextRestoreGState(outputContext);
        }

        if (tintColor) {
            CGContextSaveGState(outputContext);
            CGContextSetFillColorWithColor(outputContext, tintColor.CGColor);
            CGContextFillRect(outputContext, imageRect);
            CGContextRestoreGState(outputContext);
        }

        UIImage *outputImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();

        return outputImage;
    }

How to put data containing double-quotes in string variable?

You can escape (this is how this principle is called) the double quotes by prefixing them with another double quote. You can put them in a string as follows:

Dim MyVar as string = "some text ""hello"" "

This will give the MyVar variable a value of some text "hello".

Linq: GroupBy, Sum and Count

sometimes you need to select some fields by FirstOrDefault() or singleOrDefault() you can use the below query:

List<ResultLine> result = Lines
    .GroupBy(l => l.ProductCode)
    .Select(cl => new Models.ResultLine
            {
                ProductName = cl.select(x=>x.Name).FirstOrDefault(),
                Quantity = cl.Count().ToString(),
                Price = cl.Sum(c => c.Price).ToString(),
            }).ToList();

How to create windows service from java jar?

The easiest solution I found for this so far is the Non-Sucking Service Manager

Usage would be

nssm install <servicename> "C:\Program Files\Java\jre7\java.exe" "-jar <path-to-jar-file>"

iPhone Debugging: How to resolve 'failed to get the task for process'?

I received this error when I tried to launch app from Xcode as I figured I had selected distribution profile only. Build was successful so I created .ipa file. I used testflightapp.com to run the app. You can use iTunes as well.

Python NLTK: SyntaxError: Non-ASCII character '\xc3' in file (Sentiment Analysis -NLP)

Add the following to the top of your file # coding=utf-8

If you go to the link in the error you can seen the reason why:

Defining the Encoding

Python will default to ASCII as standard encoding if no other encoding hints are given. To define a source code encoding, a magic comment must be placed into the source files either as first or second line in the file, such as: # coding=

Calling class staticmethod within the class body?

If the "core problem" is assigning class variables using functions, an alternative is to use a metaclass (it's kind of "annoying" and "magical" and I agree that the static method should be callable inside the class, but unfortunately it isn't). This way, we can refactor the behavior into a standalone function and don't clutter the class.

class KlassMetaClass(type(object)):
    @staticmethod
    def _stat_func():
        return 42

    def __new__(cls, clsname, bases, attrs):
        # Call the __new__ method from the Object metaclass
        super_new = super().__new__(cls, clsname, bases, attrs)
        # Modify class variable "_ANS"
        super_new._ANS = cls._stat_func()
        return super_new

class Klass(object, metaclass=KlassMetaClass):
    """
    Class that will have class variables set pseudo-dynamically by the metaclass
    """
    pass

print(Klass._ANS) # prints 42

Using this alternative "in the real world" may be problematic. I had to use it to override class variables in Django classes, but in other circumstances maybe it's better to go with one of the alternatives from the other answers.

Comparing two arrays of objects, and exclude the elements who match values into new array in JS

Here is another solution using Lodash:

var _ = require('lodash');

var result1 = [
    {id:1, name:'Sandra', type:'user', username:'sandra'},
    {id:2, name:'John', type:'admin', username:'johnny2'},
    {id:3, name:'Peter', type:'user', username:'pete'},
    {id:4, name:'Bobby', type:'user', username:'be_bob'}
];

var result2 = [
    {id:2, name:'John', email:'[email protected]'},
    {id:4, name:'Bobby', email:'[email protected]'}
];

// filter all those that do not match
var result = types1.filter(function(o1){
    // if match found return false
    return _.findIndex(types2, {'id': o1.id, 'name': o1.name}) !== -1 ? false : true;
});

console.log(result);

HTML.ActionLink method

Use named parameters for readability and to avoid confusions.

@Html.ActionLink(
            linkText: "Click Here",
            actionName: "Action",
            controllerName: "Home",
            routeValues: new { Identity = 2577 },
            htmlAttributes: null)

Using Mysql in the command line in osx - command not found?

That means /usr/local/mysql/bin/mysql is not in the PATH variable..

Either execute /usr/local/mysql/bin/mysql to get your mysql shell,

or type this in your terminal:

PATH=$PATH:/usr/local/mysql/bin

to add that to your PATH variable so you can just run mysql without specifying the path

"Fatal error: Cannot redeclare <function>"

I had this pop up recently where a function was being called prior to its definition in the same file, and it didnt have the returned value assigned to a variable. Adding a var for the return value to be assigned to made the error go away.

"A connection attempt failed because the connected party did not properly respond after a period of time" using WebClient

I know this post was posted 5 years ago, but I had this problem recently. It may be cause by corporate network limitations. So my solution is letting WebClient go through proxy server to make the call. Here is the code which worked for me. Hope it helps.

        using (WebClient client = new WebClient())
        {
            client.Encoding = Encoding.UTF8;
            WebProxy proxy = new WebProxy("your proxy host IP", port);
            client.Proxy = proxy;
            string sourceUrl = "xxxxxx";
            try
            {
                using (Stream stream = client.OpenRead(new Uri(noaaSourceUrl)))
                {
                    //......
                }
            }
            catch (Exception ex)
            {
                throw;
            }
        }

How to pad a string to a fixed length with spaces in Python?

If you have python version 3.6 or higher you can use f strings

>>> string = "John"
>>> f"{string:<15}"
'John           '

Or if you'd like it to the left

>>> f"{string:>15}"
'          John'

Centered

>>> f"{string:^15}"
'     John      '

For more variations, feel free to check out the docs: https://docs.python.org/3/library/string.html#format-string-syntax

Find the index of a char in string?

Contanis occur if using the method of the present letter, and store the corresponding number using the IndexOf method, see example below.

    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
    Dim myString As String = "abcdef"
    Dim numberString As String = String.Empty

    If myString.Contains("d") Then
        numberString = myString.IndexOf("d")
    End If
End Sub

Another sample with TextBox

  Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
    Dim myString As String = "abcdef"
    Dim numberString As String = String.Empty

    If myString.Contains(me.TextBox1.Text) Then
        numberString = myString.IndexOf(Me.TextBox1.Text)
    End If
End Sub

Regards

Use superscripts in R axis labels

The other option in this particular case would be to type the degree symbol: °

R seems to handle it fine. Type Option-k on a Mac to get it. Not sure about other platforms.

How do I reference a cell within excel named range?

Add a column to the left so that B10 to B20 is your named range Age.

Set A10 to A20 so that A10 = 1, A11= 2,... A20 = 11 and give the range A10 to A20 a name e.g. AgeIndex.

The 5th element can be then found by using an array formula:

=sum( Age * (1 * (AgeIndex = 5) )

As it's an array formula you'll need to press Ctrl + Shift + Return to make it work and not just return. Doing that, the formula will be turned into an array formula:

{=sum( Age * (1 * (AgeIndex = 5) )}

Simple prime number generator in Python

Here's a simple (Python 2.6.2) solution... which is in-line with the OP's original request (now six-months old); and should be a perfectly acceptable solution in any "programming 101" course... Hence this post.

import math

def isPrime(n):
    for i in range(2, int(math.sqrt(n)+1)):
        if n % i == 0: 
            return False;
    return n>1;

print 2
for n in range(3, 50):
    if isPrime(n):
        print n

This simple "brute force" method is "fast enough" for numbers upto about about 16,000 on modern PC's (took about 8 seconds on my 2GHz box).

Obviously, this could be done much more efficiently, by not recalculating the primeness of every even number, or every multiple of 3, 5, 7, etc for every single number... See the Sieve of Eratosthenes (see eliben's implementation above), or even the Sieve of Atkin if you're feeling particularly brave and/or crazy.

Caveat Emptor: I'm a python noob. Please don't take anything I say as gospel.

.mp4 file not playing in chrome

Encountering the same problem, I solved this by reconverting the file with default mp4 settings in iMovie.

A simple explanation of Naive Bayes Classification

I realize that this is an old question, with an established answer. The reason I'm posting is that is the accepted answer has many elements of k-NN (k-nearest neighbors), a different algorithm.

Both k-NN and NaiveBayes are classification algorithms. Conceptually, k-NN uses the idea of "nearness" to classify new entities. In k-NN 'nearness' is modeled with ideas such as Euclidean Distance or Cosine Distance. By contrast, in NaiveBayes, the concept of 'probability' is used to classify new entities.

Since the question is about Naive Bayes, here's how I'd describe the ideas and steps to someone. I'll try to do it with as few equations and in plain English as much as possible.

First, Conditional Probability & Bayes' Rule

Before someone can understand and appreciate the nuances of Naive Bayes', they need to know a couple of related concepts first, namely, the idea of Conditional Probability, and Bayes' Rule. (If you are familiar with these concepts, skip to the section titled Getting to Naive Bayes')

Conditional Probability in plain English: What is the probability that something will happen, given that something else has already happened.

Let's say that there is some Outcome O. And some Evidence E. From the way these probabilities are defined: The Probability of having both the Outcome O and Evidence E is: (Probability of O occurring) multiplied by the (Prob of E given that O happened)

One Example to understand Conditional Probability:

Let say we have a collection of US Senators. Senators could be Democrats or Republicans. They are also either male or female.

If we select one senator completely randomly, what is the probability that this person is a female Democrat? Conditional Probability can help us answer that.

Probability of (Democrat and Female Senator)= Prob(Senator is Democrat) multiplied by Conditional Probability of Being Female given that they are a Democrat.

  P(Democrat & Female) = P(Democrat) * P(Female | Democrat) 

We could compute the exact same thing, the reverse way:

  P(Democrat & Female) = P(Female) * P(Democrat | Female) 

Understanding Bayes Rule

Conceptually, this is a way to go from P(Evidence| Known Outcome) to P(Outcome|Known Evidence). Often, we know how frequently some particular evidence is observed, given a known outcome. We have to use this known fact to compute the reverse, to compute the chance of that outcome happening, given the evidence.

P(Outcome given that we know some Evidence) = P(Evidence given that we know the Outcome) times Prob(Outcome), scaled by the P(Evidence)

The classic example to understand Bayes' Rule:

Probability of Disease D given Test-positive = 

               P(Test is positive|Disease) * P(Disease)
     _______________________________________________________________
     (scaled by) P(Testing Positive, with or without the disease)

Now, all this was just preamble, to get to Naive Bayes.

Getting to Naive Bayes'

So far, we have talked only about one piece of evidence. In reality, we have to predict an outcome given multiple evidence. In that case, the math gets very complicated. To get around that complication, one approach is to 'uncouple' multiple pieces of evidence, and to treat each of piece of evidence as independent. This approach is why this is called naive Bayes.

P(Outcome|Multiple Evidence) = 
P(Evidence1|Outcome) * P(Evidence2|outcome) * ... * P(EvidenceN|outcome) * P(Outcome)
scaled by P(Multiple Evidence)

Many people choose to remember this as:

                      P(Likelihood of Evidence) * Prior prob of outcome
P(outcome|evidence) = _________________________________________________
                                         P(Evidence)

Notice a few things about this equation:

  • If the Prob(evidence|outcome) is 1, then we are just multiplying by 1.
  • If the Prob(some particular evidence|outcome) is 0, then the whole prob. becomes 0. If you see contradicting evidence, we can rule out that outcome.
  • Since we divide everything by P(Evidence), we can even get away without calculating it.
  • The intuition behind multiplying by the prior is so that we give high probability to more common outcomes, and low probabilities to unlikely outcomes. These are also called base rates and they are a way to scale our predicted probabilities.

How to Apply NaiveBayes to Predict an Outcome?

Just run the formula above for each possible outcome. Since we are trying to classify, each outcome is called a class and it has a class label. Our job is to look at the evidence, to consider how likely it is to be this class or that class, and assign a label to each entity. Again, we take a very simple approach: The class that has the highest probability is declared the "winner" and that class label gets assigned to that combination of evidences.

Fruit Example

Let's try it out on an example to increase our understanding: The OP asked for a 'fruit' identification example.

Let's say that we have data on 1000 pieces of fruit. They happen to be Banana, Orange or some Other Fruit. We know 3 characteristics about each fruit:

  1. Whether it is Long
  2. Whether it is Sweet and
  3. If its color is Yellow.

This is our 'training set.' We will use this to predict the type of any new fruit we encounter.

Type           Long | Not Long || Sweet | Not Sweet || Yellow |Not Yellow|Total
             ___________________________________________________________________
Banana      |  400  |    100   || 350   |    150    ||  450   |  50      |  500
Orange      |    0  |    300   || 150   |    150    ||  300   |   0      |  300
Other Fruit |  100  |    100   || 150   |     50    ||   50   | 150      |  200
            ____________________________________________________________________
Total       |  500  |    500   || 650   |    350    ||  800   | 200      | 1000
             ___________________________________________________________________

We can pre-compute a lot of things about our fruit collection.

The so-called "Prior" probabilities. (If we didn't know any of the fruit attributes, this would be our guess.) These are our base rates.

 P(Banana)      = 0.5 (500/1000)
 P(Orange)      = 0.3
 P(Other Fruit) = 0.2

Probability of "Evidence"

p(Long)   = 0.5
P(Sweet)  = 0.65
P(Yellow) = 0.8

Probability of "Likelihood"

P(Long|Banana) = 0.8
P(Long|Orange) = 0  [Oranges are never long in all the fruit we have seen.]
 ....

P(Yellow|Other Fruit)     =  50/200 = 0.25
P(Not Yellow|Other Fruit) = 0.75

Given a Fruit, how to classify it?

Let's say that we are given the properties of an unknown fruit, and asked to classify it. We are told that the fruit is Long, Sweet and Yellow. Is it a Banana? Is it an Orange? Or Is it some Other Fruit?

We can simply run the numbers for each of the 3 outcomes, one by one. Then we choose the highest probability and 'classify' our unknown fruit as belonging to the class that had the highest probability based on our prior evidence (our 1000 fruit training set):

P(Banana|Long, Sweet and Yellow) 
      P(Long|Banana) * P(Sweet|Banana) * P(Yellow|Banana) * P(banana)
    = _______________________________________________________________
                      P(Long) * P(Sweet) * P(Yellow)
                      
    = 0.8 * 0.7 * 0.9 * 0.5 / P(evidence)

    = 0.252 / P(evidence)


P(Orange|Long, Sweet and Yellow) = 0


P(Other Fruit|Long, Sweet and Yellow)
      P(Long|Other fruit) * P(Sweet|Other fruit) * P(Yellow|Other fruit) * P(Other Fruit)
    = ____________________________________________________________________________________
                                          P(evidence)

    = (100/200 * 150/200 * 50/200 * 200/1000) / P(evidence)

    = 0.01875 / P(evidence)

By an overwhelming margin (0.252 >> 0.01875), we classify this Sweet/Long/Yellow fruit as likely to be a Banana.

Why is Bayes Classifier so popular?

Look at what it eventually comes down to. Just some counting and multiplication. We can pre-compute all these terms, and so classifying becomes easy, quick and efficient.

Let z = 1 / P(evidence). Now we quickly compute the following three quantities.

P(Banana|evidence) = z * Prob(Banana) * Prob(Evidence1|Banana) * Prob(Evidence2|Banana) ...
P(Orange|Evidence) = z * Prob(Orange) * Prob(Evidence1|Orange) * Prob(Evidence2|Orange) ...
P(Other|Evidence)  = z * Prob(Other)  * Prob(Evidence1|Other)  * Prob(Evidence2|Other)  ...

Assign the class label of whichever is the highest number, and you are done.

Despite the name, Naive Bayes turns out to be excellent in certain applications. Text classification is one area where it really shines.

Hope that helps in understanding the concepts behind the Naive Bayes algorithm.

Smooth scrolling when clicking an anchor link

I did this for both "/xxxxx#asdf" and "#asdf" href anchors

$("a[href*=#]").on('click', function(event){
    var href = $(this).attr("href");
    if ( /(#.*)/.test(href) ){
      var hash = href.match(/(#.*)/)[0];
      var path = href.match(/([^#]*)/)[0];

      if (window.location.pathname == path || path.length == 0){
        event.preventDefault();
        $('html,body').animate({scrollTop:$(this.hash).offset().top}, 1000);
        window.location.hash = hash;
      }
    }
});