Programs & Examples On #Fastercsv

Popular Ruby library/gem for working with CSV format files.

How to start rails server?

Make sure you're in the right directory when you start the server

sites>yoursite> rails s

Requested bean is currently in creation: Is there an unresolvable circular reference?

In my case, I was defining a bean and autowiring it in the constructor of the same class file.

@SpringBootApplication
public class MyApplication {
    private MyBean myBean;

    public MyApplication(MyBean myBean) {
        this.myBean = myBean;
    }

    @Bean
    public MyBean myBean() {
        return new MyBean();
    }
}

My solution was to move the bean definition to another class file.

@Configuration
public CustomConfig {
    @Bean
    public MyBean myBean() {
        return new MyBean();
    }
}

Read file As String

The code finally used is the following from:

http://www.java2s.com/Code/Java/File-Input-Output/ConvertInputStreamtoString.htm

public static String convertStreamToString(InputStream is) throws Exception {
    BufferedReader reader = new BufferedReader(new InputStreamReader(is));
    StringBuilder sb = new StringBuilder();
    String line = null;
    while ((line = reader.readLine()) != null) {
      sb.append(line).append("\n");
    }
    reader.close();
    return sb.toString();
}

public static String getStringFromFile (String filePath) throws Exception {
    File fl = new File(filePath);
    FileInputStream fin = new FileInputStream(fl);
    String ret = convertStreamToString(fin);
    //Make sure you close all streams.
    fin.close();        
    return ret;
}

Test if string begins with a string?

There are several ways to do this:

InStr

You can use the InStr build-in function to test if a String contains a substring. InStr will either return the index of the first match, or 0. So you can test if a String begins with a substring by doing the following:

If InStr(1, "Hello World", "Hello W") = 1 Then
    MsgBox "Yep, this string begins with Hello W!"
End If

If InStr returns 1, then the String ("Hello World"), begins with the substring ("Hello W").

Like

You can also use the like comparison operator along with some basic pattern matching:

If "Hello World" Like "Hello W*" Then
    MsgBox "Yep, this string begins with Hello W!"
End If

In this, we use an asterisk (*) to test if the String begins with our substring.

How to fire an event when v-model changes?

Just to add to the correct answer above, in Vue.JS v1.0 you can write

<a v-on:click="doSomething">

So in this example it would be

 v-on:change="foo"

See: http://v1.vuejs.org/guide/syntax.html#Arguments

How do I fix MSB3073 error in my post-build event?

In my case, the dll I was creating by building the project was still in use in the background. I killed the application and then xcopy worked fine as expected.

How to display a "busy" indicator with jQuery?

To extend Rodrigo's solution a little - for requests that are executed frequently, you may only want to display the loading image if the request takes more than a minimum time interval, otherwise the image will be continually popping up and quickly disappearing

var loading = false;

$.ajaxSetup({
    beforeSend: function () {
        // Display loading icon if AJAX call takes >1 second
        loading = true;
        setTimeout(function () {
            if (loading) {
                // show loading image
            }
        }, 1000);            
    },
    complete: function () {
        loading = false;
        // hide loading image
    }
});

What integer hash function are good that accepts an integer hash key?

  • 32-bits multiplicative method (very fast) see @rafal

    #define hash32(x) ((x)*2654435761)
    #define H_BITS 24 // Hashtable size
    #define H_SHIFT (32-H_BITS)
    unsigned hashtab[1<<H_BITS]  
    .... 
    unsigned slot = hash32(x) >> H_SHIFT
    
  • 32-bits and 64-bits (good distribution) at : MurmurHash

  • Integer Hash Function

What does "request for member '*******' in something not a structure or union" mean?

It may means that you forgot include a header file that define this struct/union. For example:

foo.h file:

typedef union
{
    struct
    {
        uint8_t FIFO_BYTES_AVAILABLE    : 4;
        uint8_t STATE                   : 3;
        uint8_t CHIP_RDY                : 1;
    };
    uint8_t status;
} RF_CHIP_STATUS_t;

RF_CHIP_STATUS_t getStatus();

main.c file:

.
.
.
if (getStatus().CHIP_RDY) /* This will generate the error, you must add the  #include "foo.h" */
.
.
.

Why should I use var instead of a type?

In this case it is just coding style.

Use of var is only necessary when dealing with anonymous types.
In other situations it's a matter of taste.

Eclipse error "ADB server didn't ACK, failed to start daemon"

This didn't start happening for me until I rooted my Samsung Galaxy S III phone (following the xda-developer forum guide).

It happens pretty randomly, but it's definitely occurring while running Eclipse.

Killing the adb.exe process and restarting it solves the problem.

Google Chromecast sender error if Chromecast extension is not installed or using incognito

Update: After several attempts, it looks like this may have been fixed in latest Chrome builds (per Paul Irish's comment below). That would suggest we will see this fixed in stable Chrome June-July 2016. Let's see ...

This is a known bug with the official Chromecast JavaScript library. Instead of failing silently, it dumps these error messages in all non-Chrome browsers as well as Chrome browsers where the Chromecast extension isn't present.

The Chromecast team have indicated they won't fix this bug.

If you are a developer shipping with this library, you can't do anything about it according to Chromecast team. You can only inform users to ignore the errors. (I believe Chromecast team is not entirely correct as the library could, at the least, avoid requesting the extension scipt if the browser is not Chrome. And I suspect it could be possible to suppress the error even if it is Chrome, but haven't tried anything.)

If you are a user annoyed by these console messages, you can switch to Chrome if not using it already. Within Chrome, either:

Update [Nov 13, 2014]: The problem has now been acknowledged by Google. A member of the Chromecast team seems to suggest the issue will be bypassed by a change the team is currently working on.

Update 2 [Feb 17, 2015]: The team claim there's nothing they can do to remove the error logs as it's a standard Chrome network error and they are still working on a long-term fix. Public comments on the bug tracker were closed with that update.

Update 3 [Dec 4, 2015]: This has finally been fixed! In the end, Chrome team simply added some code to block out this specific error. Hopefully some combination of devtools and extensions API will be improved in the future to make it possible to fix this kind of problem without patching the browser. Chrome Canary already has the patch, so it should roll out to all users around mid-January. Additionally, the team has confirmed the issue no longer affects other browsers as the SDK was updated to only activate if it's in Chrome.

Update 4 (April 30): Nope, not yet anyway. Thankfully Google's developer relations team are more aware than certain other stakeholders how badly this has affected developer experience. More whitelist updates have recently been made to clobber these log messages. Current status at top of the post.

java.net.SocketException: Connection reset by peer: socket write error When serving a file

This problem is usually caused by writing to a connection that had already been closed by the peer. In this case it could indicate that the user cancelled the download for example.

Setting default permissions for newly created files and sub-directories under a directory in Linux?

Here's how to do it using default ACLs, at least under Linux.

First, you might need to enable ACL support on your filesystem. If you are using ext4 then it is already enabled. Other filesystems (e.g., ext3) need to be mounted with the acl option. In that case, add the option to your /etc/fstab. For example, if the directory is located on your root filesystem:

/dev/mapper/qz-root   /    ext3    errors=remount-ro,acl   0  1

Then remount it:

mount -oremount /

Now, use the following command to set the default ACL:

setfacl -dm u::rwx,g::rwx,o::r /shared/directory

All new files in /shared/directory should now get the desired permissions. Of course, it also depends on the application creating the file. For example, most files won't be executable by anyone from the start (depending on the mode argument to the open(2) or creat(2) call), just like when using umask. Some utilities like cp, tar, and rsync will try to preserve the permissions of the source file(s) which will mask out your default ACL if the source file was not group-writable.

Hope this helps!

How to change the timeout on a .NET WebClient object

'CORRECTED VERSION OF LAST FUNCTION IN VISUAL BASIC BY GLENNG

Protected Overrides Function GetWebRequest(ByVal address As System.Uri) As System.Net.WebRequest
            Dim w As System.Net.WebRequest = MyBase.GetWebRequest(address)
            If _TimeoutMS <> 0 Then
                w.Timeout = _TimeoutMS
            End If
            Return w  '<<< NOTICE: MyBase.GetWebRequest(address) DOES NOT WORK >>>
        End Function

Killing a process using Java

If you start the process from with in your Java application (ex. by calling Runtime.exec() or ProcessBuilder.start()) then you have a valid Process reference to it, and you can invoke the destroy() method in Process class to kill that particular process.

But be aware that if the process that you invoke creates new sub-processes, those may not be terminated (see http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4770092).

On the other hand, if you want to kill external processes (which you did not spawn from your Java app), then one thing you can do is to call O/S utilities which allow you to do that. For example, you can try a Runtime.exec() on kill command under Unix / Linux and check for return values to ensure that the application was killed or not (0 means success, -1 means error). But that of course will make your application platform dependent.

Detect all changes to a <input type="text"> (immediately) using JQuery

This is the fastest& clean way to do that :

I'm using Jquery-->

$('selector').on('change', function () {
    console.log(this.id+": "+ this.value);
});

It is working pretty fine for me.

JavaScript - Get minutes between two dates

A simple function to perform this calculation:

function getMinutesBetweenDates(startDate, endDate) {
    var diff = endDate.getTime() - startDate.getTime();
    return (diff / 60000);
}

Java ArrayList replace at specific index

We can replace element in arraylist using ArrayList Set() method.We are a example for this as below.

Create Arraylist

 ArrayList<String> arr = new ArrayList<String>();
 arr.add("c");
 arr.add("php");
 arr.add("html");
 arr.add("java");

Now replcae Element on index 2

 arr.set(2,"Mysql");
 System.out.println("after replace arrayList is = " + arr);

OutPut :

 after replace arrayList is = [c, php, Mysql, java]

Reference :

Replace element in ArrayList

How to get out of while loop in java with Scanner method "hasNext" as condition?

Your condition is right (though you should drop the == true). What is happening is that the scanner will keep going until it reaches the end of the input. Try Ctrl+D, or pipe the input from a file (java myclass < input.txt).

Doctrine 2: Update query with query builder

I think you need to use Expr with ->set() (However THIS IS NOT SAFE and you shouldn't do it):

$qb = $this->em->createQueryBuilder();
$q = $qb->update('models\User', 'u')
        ->set('u.username', $qb->expr()->literal($username))
        ->set('u.email', $qb->expr()->literal($email))
        ->where('u.id = ?1')
        ->setParameter(1, $editId)
        ->getQuery();
$p = $q->execute();

It's much safer to make all your values parameters instead:

$qb = $this->em->createQueryBuilder();
$q = $qb->update('models\User', 'u')
        ->set('u.username', '?1')
        ->set('u.email', '?2')
        ->where('u.id = ?3')
        ->setParameter(1, $username)
        ->setParameter(2, $email)
        ->setParameter(3, $editId)
        ->getQuery();
$p = $q->execute();

php $_GET and undefined index

I always use a utility function/class for reading from the $_GET and $_POST arrays to avoid having to always check the index exists... Something like this will do the trick.

class Input {
function get($name) {
    return isset($_GET[$name]) ? $_GET[$name] : null;
}

function post($name) {
    return isset($_POST[$name]) ? $_POST[$name] : null;
}

function get_post($name) {
    return $this->get($name) ? $this->get($name) : $this->post($name);
}
}
$input = new Input;
$page = $input->get_post('page');

pandas: to_numeric for multiple columns

df[cols] = pd.to_numeric(df[cols].stack(), errors='coerce').unstack()

How to get min, seconds and milliseconds from datetime.now() in python?

Sorry to open an old thread but I'm posting just in case it helps someone. This seems to be the easiest way to do this in Python 3.

from datetime import datetime

Date = str(datetime.now())[:10]
Hour = str(datetime.now())[11:13]
Minute = str(datetime.now())[14:16]
Second = str(datetime.now())[17:19]
Millisecond = str(datetime.now())[20:]

If you need the values as a number just cast them as an int e.g

Hour = int(str(datetime.now())[11:13])

How do I add BundleConfig.cs to my project?

If you are using "MVC 5" you may not see the file, and you should follow these steps: http://www.techjunkieblog.com/2015/05/aspnet-mvc-empty-project-adding.html

If you are using "ASP.NET 5" it has stopped using "bundling and minification" instead was replaced by gulp, bower, and npm. More information see https://jeffreyfritz.com/2015/05/where-did-my-asp-net-bundles-go-in-asp-net-5/

Scala: what is the best way to append an element to an Array?

You can use :+ to append element to array and +: to prepend it:

0 +: array :+ 4

should produce:

res3: Array[Int] = Array(0, 1, 2, 3, 4)

It's the same as with any other implementation of Seq.

Measuring the distance between two coordinates in PHP

The multiplier is changed at every coordinate because of the great circle distance theory as written here :

http://en.wikipedia.org/wiki/Great-circle_distance

and you can calculate the nearest value using this formula described here:

http://en.wikipedia.org/wiki/Great-circle_distance#Worked_example

the key is converting each degree - minute - second value to all degree value:

N 36°7.2', W 86°40.2'  N = (+) , W = (-), S = (-), E = (+) 
referencing the Greenwich meridian and Equator parallel

(phi)     36.12° = 36° + 7.2'/60' 

(lambda)  -86.67° = 86° + 40.2'/60'

Set background colour of cell to RGB value of data in cell

Sub AddColor()
    For Each cell In Selection
        R = Round(cell.Value)
        G = Round(cell.Offset(0, 1).Value)
        B = Round(cell.Offset(0, 2).Value)
        Cells(cell.Row, 1).Resize(1, 4).Interior.Color = RGB(R, G, B)
    Next cell
End Sub

Assuming that there are 3 columns R, G and B (in this order). Select first column ie R. press alt+F11 and run the above code. We have to select the first column (containing R or red values) and run the code every time we change the values to reflect the changes.

I hope this simpler code helps !

Programmatically trigger "select file" dialog box

Make sure you are using binding to get component props in REACT

class FileUploader extends Component {
  constructor (props) {
    super(props);
    this.handleClick = this.handleClick.bind(this);
  }
   onChange=(e,props)=>{
    const files = e.target.files;
    const selectedFile = files[0];
    ProcessFileUpload(selectedFile,props.ProgressCallBack,props.ErrorCallBack,props.CompleatedCallBack,props.BaseURL,props.Location,props.FilesAllowed);
  }
   handleClick = () => {
    this.refs.fileUploader.click();
  }
  render()
  {
  return(
      <div>
        <button type="button" onClick={this.handleClick}>Select File</button>  
        <input type='file' onChange={(e)=>this.onChange(e,this.props)} ref="fileUploader" style={{display:"none"}} />
      </div>)
  }
}

ASP.NET document.getElementById('<%=Control.ClientID%>'); returns null

Gotcha!

You have to use RegisterStartupScript instead of RegisterClientScriptBlock

Here My Example.

MasterPage:

<%@ Master Language="C#" AutoEventWireup="true" CodeBehind="MasterPage.master.cs"
    Inherits="prueba.MasterPage" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>

    <script type="text/javascript">

        function confirmCallBack() {
            var a = document.getElementById('<%= Page.Master.FindControl("ContentPlaceHolder1").FindControl("Button1").ClientID %>');

            alert(a.value);

        }

    </script>

    <asp:ContentPlaceHolder ID="head" runat="server">
    </asp:ContentPlaceHolder>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:ContentPlaceHolder ID="ContentPlaceHolder1" runat="server">
        </asp:ContentPlaceHolder>
    </div>
    </form>
</body>
</html>

WebForm1.aspx

<%@ Page Title="" Language="C#" MasterPageFile="~/MasterPage.Master" AutoEventWireup="true"
    CodeBehind="WebForm1.aspx.cs" Inherits="prueba.WebForm1" %>

<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">

</asp:Content>

<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
<asp:Button ID="Button1" runat="server" Text="Button" />
</asp:Content>

WebForm1.aspx.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace prueba
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            ClientScript.RegisterStartupScript(this.GetType(), "js", "confirmCallBack();", true);

        }
    }
}

Passing by reference in C

Your example works because you are passing the address of your variable to a function that manipulates its value with the dereference operator.

While C does not support reference data types, you can still simulate passing-by-reference by explicitly passing pointer values, as in your example.

The C++ reference data type is less powerful but considered safer than the pointer type inherited from C. This would be your example, adapted to use C++ references:

void f(int &j) {
  j++;
}

int main() {
  int i = 20;
  f(i);
  printf("i = %d\n", i);

  return 0;
}

typesafe select onChange event using reactjs and typescript

JSX:

<select value={ this.state.foo } onChange={this.handleFooChange}>
    <option value="A">A</option>
    <option value="B">B</option>
</select>

TypeScript:

private handleFooChange = (event: React.FormEvent<HTMLSelectElement>) => {
    const element = event.target as HTMLSelectElement;
    this.setState({ foo: element.value });
}

Css transition from display none to display block, navigation with subnav

You can do this with animation-keyframe rather than transition. Change your hover declaration and add the animation keyframe, you might also need to add browser prefixes for -moz- and -webkit-. See https://developer.mozilla.org/en/docs/Web/CSS/@keyframes for more detailed info.

_x000D_
_x000D_
nav.main ul ul {_x000D_
    position: absolute;_x000D_
    list-style: none;_x000D_
    display: none;_x000D_
    opacity: 0;_x000D_
    visibility: hidden;_x000D_
    padding: 10px;_x000D_
    background-color: rgba(92, 91, 87, 0.9);_x000D_
    -webkit-transition: opacity 600ms, visibility 600ms;_x000D_
            transition: opacity 600ms, visibility 600ms;_x000D_
}_x000D_
_x000D_
nav.main ul li:hover ul {_x000D_
    display: block;_x000D_
    visibility: visible;_x000D_
    opacity: 1;_x000D_
    animation: fade 1s;_x000D_
}_x000D_
_x000D_
@keyframes fade {_x000D_
    0% {_x000D_
        opacity: 0;_x000D_
    }_x000D_
_x000D_
    100% {_x000D_
        opacity: 1;_x000D_
    }_x000D_
}
_x000D_
<nav class="main">_x000D_
    <ul>_x000D_
        <li>_x000D_
            <a href="">Lorem</a>_x000D_
            <ul>_x000D_
                <li><a href="">Ipsum</a></li>_x000D_
                <li><a href="">Dolor</a></li>_x000D_
                <li><a href="">Sit</a></li>_x000D_
                <li><a href="">Amet</a></li>_x000D_
            </ul>_x000D_
        </li>_x000D_
    </ul>_x000D_
</nav>
_x000D_
_x000D_
_x000D_

Here is an update on your fiddle. https://jsfiddle.net/orax9d9u/1/

Delete column from SQLite table

For SQLite3 c++ :

void GetTableColNames( tstring sTableName , std::vector<tstring> *pvsCols )
{
    UASSERT(pvsCols);

    CppSQLite3Table table1;

    tstring sDML = StringOps::std_sprintf(_T("SELECT * FROM %s") , sTableName.c_str() );



    table1 = getTable( StringOps::tstringToUTF8string(sDML).c_str() );

    for ( int nCol = 0 ; nCol < table1.numFields() ; nCol++ )
    {
        const char* pch1 = table1.fieldName(nCol);  

        pvsCols->push_back( StringOps::UTF8charTo_tstring(pch1));
    }
}


bool ColExists( tstring sColName )
{
    bool bColExists = true;

    try
    {
        tstring sQuery = StringOps::std_sprintf(_T("SELECT %s FROM MyOriginalTable LIMIT 1;") , sColName.c_str() );

        ShowVerbalMessages(false);

        CppSQLite3Query q = execQuery( StringOps::tstringTo_stdString(sQuery).c_str() );

        ShowVerbalMessages(true);
    }
    catch (CppSQLite3Exception& e)
    {
        bColExists = false;
    }

    return bColExists;
}

void DeleteColumns( std::vector<tstring> *pvsColsToDelete )
{
    UASSERT(pvsColsToDelete);

    execDML( StringOps::tstringTo_stdString(_T("begin transaction;")).c_str() );


    std::vector<tstring> vsCols;
    GetTableColNames( _T("MyOriginalTable") , &vsCols );


    CreateFields( _T("TempTable1") , false );

    tstring sFieldNamesSeperatedByCommas;

    for ( int nCol = 0 ; nCol < vsCols.size() ; nCol++ )
    {

        tstring sColNameCurr = vsCols.at(nCol);

        bool bUseCol = true;

        for ( int nColsToDelete = 0; nColsToDelete < pvsColsToDelete->size() ; nColsToDelete++ )
        {
            if ( pvsColsToDelete->at(nColsToDelete) == sColNameCurr )
            {
                bUseCol = false;
                break;
            }
        }

        if ( bUseCol )
            sFieldNamesSeperatedByCommas+= (sColNameCurr + _T(","));

    }

    if ( sFieldNamesSeperatedByCommas.at( int(sFieldNamesSeperatedByCommas.size()) - 1) == _T(','))
        sFieldNamesSeperatedByCommas.erase( int(sFieldNamesSeperatedByCommas.size()) - 1 );

    tstring sDML;


    sDML = StringOps::std_sprintf(_T("insert into TempTable1 SELECT %s FROM MyOriginalTable;\n") , sFieldNamesSeperatedByCommas.c_str() );
    execDML( StringOps::tstringTo_stdString(sDML).c_str() );

    sDML = StringOps::std_sprintf(_T("ALTER TABLE MyOriginalTable RENAME TO MyOriginalTable_old\n") );
    execDML( StringOps::tstringTo_stdString(sDML).c_str() );

    sDML = StringOps::std_sprintf(_T("ALTER TABLE TempTable1 RENAME TO MyOriginalTable\n") );
    execDML( StringOps::tstringTo_stdString(sDML).c_str() );


    sDML = ( _T("DROP TABLE MyOriginalTable_old;") );   
    execDML( StringOps::tstringTo_stdString(sDML).c_str() );


    execDML( StringOps::tstringTo_stdString(_T("commit transaction;")).c_str() );   
}

What is the $$hashKey added to my JSON.stringify result

Update : From Angular v1.5, track by $index is now the standard syntax instead of using link as it gave me a ng-repeat dupes error.

I ran into this for a nested ng-repeat and the below worked.

<tbody>
    <tr ng-repeat="row in data track by $index">
    <td ng-repeat="field in headers track by $index">{{row[field.caption] }}</td>
</tr>

Stuck while installing Visual Studio 2015 (Update for Microsoft Windows (KB2999226))

I have the same problem today, stuck on the kb2999226 for over an hour. First, i thought it is because i am using a VM on my local machine. But decided to cancel the installation, then install kb2999226 first, then install the vs2015 community again, it works out much better, the installation move forward and progressing. thx.

How do I get the YouTube video ID from a URL?

Simple regex if you have the full URL, keep it simple.

results = url.match("v=([a-zA-Z0-9]+)&?")
videoId = results[1] // watch you need.

Check if not nil and not empty in Rails shortcut?

There's a method that does this for you:

def show
  @city = @user.city.present?
end

The present? method tests for not-nil plus has content. Empty strings, strings consisting of spaces or tabs, are considered not present.

Since this pattern is so common there's even a shortcut in ActiveRecord:

def show
  @city = @user.city?
end

This is roughly equivalent.

As a note, testing vs nil is almost always redundant. There are only two logically false values in Ruby: nil and false. Unless it's possible for a variable to be literal false, this would be sufficient:

if (variable)
  # ...
end

This is preferable to the usual if (!variable.nil?) or if (variable != nil) stuff that shows up occasionally. Ruby tends to wards a more reductionist type of expression.

One reason you'd want to compare vs. nil is if you have a tri-state variable that can be true, false or nil and you need to distinguish between the last two states.

Python using enumerate inside list comprehension

Just to be really clear, this has nothing to do with enumerate and everything to do with list comprehension syntax.

This list comprehension returns a list of tuples:

[(i,j) for i in range(3) for j in 'abc']

this a list of dicts:

[{i:j} for i in range(3) for j in 'abc']

a list of lists:

[[i,j] for i in range(3) for j in 'abc']

a syntax error:

[i,j for i in range(3) for j in 'abc']

Which is inconsistent (IMHO) and confusing with dictionary comprehensions syntax:

>>> {i:j for i,j in enumerate('abcdef')}
{0: 'a', 1: 'b', 2: 'c', 3: 'd', 4: 'e', 5: 'f'}

And a set of tuples:

>>> {(i,j) for i,j in enumerate('abcdef')}
set([(0, 'a'), (4, 'e'), (1, 'b'), (2, 'c'), (5, 'f'), (3, 'd')])

As Óscar López stated, you can just pass the enumerate tuple directly:

>>> [t for t in enumerate('abcdef') ] 
[(0, 'a'), (1, 'b'), (2, 'c'), (3, 'd'), (4, 'e'), (5, 'f')]

Find max and second max salary for a employee table MySQL

without nested query

select max(e.salary) as max_salary, max(e1.salary) as 2nd_max_salary 
from employee as e
left join employee as e1 on e.salary != e1.salary
group by e.salary desc limit 1;

What's the fastest way to do a bulk insert into Postgres?

I implemented very fast Postgresq data loader with native libpq methods. Try my package https://www.nuget.org/packages/NpgsqlBulkCopy/

Working copy locked error in tortoise svn while committing

No problem... try this:

  • Go to top level SVN folder.
  • Right click on folder (that has your svn files) > TortoiseSVN > CleanUp

This will surely solve your problem. I did this lots of time... :)

Note. Make sure "Break locks" option is selected in the Cleanup dialog.

git remote add with other SSH port

You need to edit your ~/.ssh/config file. Add something like the following:

Host example.com
    Port 1234

A quick google search shows a few different resources that explain it in more detail than me.

Rethrowing exceptions in Java without losing the stack trace

In Java is almost the same:

try
{
   ...
}
catch (Exception e)
{
   if (e instanceof FooException)
     throw e;
}

How do you round a floating point number in Perl?

Whilst not disagreeing with the complex answers about half-way marks and so on, for the more common (and possibly trivial) use-case:

my $rounded = int($float + 0.5);

UPDATE

If it's possible for your $float to be negative, the following variation will produce the correct result:

my $rounded = int($float + $float/abs($float*2 || 1));

With this calculation -1.4 is rounded to -1, and -1.6 to -2, and zero won't explode.

Is it possible to pass a flag to Gulp to have it run tasks in different ways?

There's a very simple way to do on/off flags without parsing the arguments. gulpfile.js is just a file that's executed like any other, so you can do:

var flags = {
  production: false
};

gulp.task('production', function () {
  flags.production = true;
});

And use something like gulp-if to conditionally execute a step

gulp.task('build', function () {
  gulp.src('*.html')
    .pipe(gulp_if(flags.production, minify_html()))
    .pipe(gulp.dest('build/'));
});

Executing gulp build will produce a nice html, while gulp production build will minify it.

Maven – Always download sources and javadocs

In my case the "settings.xml" solution didn't work so I use this command in order to download all the sources:

mvn dependency:sources

You also can use it with other maven commands, for example:

mvn clean install dependency:sources -Dmaven.test.skip=true

To download all documentation, use the following command:

mvn dependency:resolve -Dclassifier=javadoc

Why does C++ code for testing the Collatz conjecture run faster than hand-written assembly?

For more performance: A simple change is observing that after n = 3n+1, n will be even, so you can divide by 2 immediately. And n won't be 1, so you don't need to test for it. So you could save a few if statements and write:

while (n % 2 == 0) n /= 2;
if (n > 1) for (;;) {
    n = (3*n + 1) / 2;
    if (n % 2 == 0) {
        do n /= 2; while (n % 2 == 0);
        if (n == 1) break;
    }
}

Here's a big win: If you look at the lowest 8 bits of n, all the steps until you divided by 2 eight times are completely determined by those eight bits. For example, if the last eight bits are 0x01, that is in binary your number is ???? 0000 0001 then the next steps are:

3n+1 -> ???? 0000 0100
/ 2  -> ???? ?000 0010
/ 2  -> ???? ??00 0001
3n+1 -> ???? ??00 0100
/ 2  -> ???? ???0 0010
/ 2  -> ???? ???? 0001
3n+1 -> ???? ???? 0100
/ 2  -> ???? ???? ?010
/ 2  -> ???? ???? ??01
3n+1 -> ???? ???? ??00
/ 2  -> ???? ???? ???0
/ 2  -> ???? ???? ????

So all these steps can be predicted, and 256k + 1 is replaced with 81k + 1. Something similar will happen for all combinations. So you can make a loop with a big switch statement:

k = n / 256;
m = n % 256;

switch (m) {
    case 0: n = 1 * k + 0; break;
    case 1: n = 81 * k + 1; break; 
    case 2: n = 81 * k + 1; break; 
    ...
    case 155: n = 729 * k + 425; break;
    ...
}

Run the loop until n = 128, because at that point n could become 1 with fewer than eight divisions by 2, and doing eight or more steps at a time would make you miss the point where you reach 1 for the first time. Then continue the "normal" loop - or have a table prepared that tells you how many more steps are need to reach 1.

PS. I strongly suspect Peter Cordes' suggestion would make it even faster. There will be no conditional branches at all except one, and that one will be predicted correctly except when the loop actually ends. So the code would be something like

static const unsigned int multipliers [256] = { ... }
static const unsigned int adders [256] = { ... }

while (n > 128) {
    size_t lastBits = n % 256;
    n = (n >> 8) * multipliers [lastBits] + adders [lastBits];
}

In practice, you would measure whether processing the last 9, 10, 11, 12 bits of n at a time would be faster. For each bit, the number of entries in the table would double, and I excect a slowdown when the tables don't fit into L1 cache anymore.

PPS. If you need the number of operations: In each iteration we do exactly eight divisions by two, and a variable number of (3n + 1) operations, so an obvious method to count the operations would be another array. But we can actually calculate the number of steps (based on number of iterations of the loop).

We could redefine the problem slightly: Replace n with (3n + 1) / 2 if odd, and replace n with n / 2 if even. Then every iteration will do exactly 8 steps, but you could consider that cheating :-) So assume there were r operations n <- 3n+1 and s operations n <- n/2. The result will be quite exactly n' = n * 3^r / 2^s, because n <- 3n+1 means n <- 3n * (1 + 1/3n). Taking the logarithm we find r = (s + log2 (n' / n)) / log2 (3).

If we do the loop until n = 1,000,000 and have a precomputed table how many iterations are needed from any start point n = 1,000,000 then calculating r as above, rounded to the nearest integer, will give the right result unless s is truly large.

JFrame background image

This is a simple example for adding the background image in a JFrame:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class BackgroundImageJFrame extends JFrame
{
    JButton b1;
    JLabel l1;

    public BackgroundImageJFrame()
    {
        setTitle("Background Color for JFrame");
        setSize(400,400);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setVisible(true);

        /*
        One way
        -----------------
        setLayout(new BorderLayout());
        JLabel background=new JLabel(new ImageIcon("C:\\Users\\Computer\\Downloads\\colorful design.png"));
        add(background);
        background.setLayout(new FlowLayout());
        l1=new JLabel("Here is a button");
        b1=new JButton("I am a button");
        background.add(l1);
        background.add(b1);
        */

        // Another way
        setLayout(new BorderLayout());
        setContentPane(new JLabel(new ImageIcon("C:\\Users\\Computer\\Downloads\\colorful design.png")));
        setLayout(new FlowLayout());
        l1=new JLabel("Here is a button");
        b1=new JButton("I am a button");
        add(l1);
        add(b1);
        // Just for refresh :) Not optional!
        setSize(399,399);
        setSize(400,400);
    }

    public static void main(String args[])
    {
        new BackgroundImageJFrame();
    }
} 
  • Click here for more info

Decrementing for loops

You need to give the range a -1 step

 for i in range(10,0,-1):
    print i

How to reload a page using Angularjs?

$scope.rtGo = function(){
            $window.sessionStorage.removeItem('message');
            $window.sessionStorage.removeItem('status');
        }

CSS: Force float to do a whole new line

Well, if you really need to use float declarations, you have two options:

  1. Use clear: left on the leftmost items - the con is that you'll have a fixed number of columns
  2. Make the items equal in height - either by script or by hard-coding the height in the CSS

Both of these are limiting, because they work around how floats work. However, you may consider using display: inline-block instead of float, which will achieve the similar layout. You can then adjust their alignment using vertical-align.

How to remove button shadow (android)

the @Alt-Cat answer work for me!

R.attr.borderlessButtonStyle doesn't contain shadow.

and the document of button is great.

Also, you can set this style on your custom button, in second constructor.

    public CustomButton(Context context, AttributeSet attrs) {
        this(context, attrs, R.attr.borderlessButtonStyle);
    }

postgresql - add boolean column to table set default

If you are using postgresql then you have to use column type BOOLEAN in lower case as boolean.

ALTER TABLE users ADD "priv_user" boolean DEFAULT false;

Scala Doubles, and Precision

How about :

 val value = 1.4142135623730951

//3 decimal places
println((value * 1000).round / 1000.toDouble)

//4 decimal places
println((value * 10000).round / 10000.toDouble)

"Can't find Project or Library" for standard VBA functions

I've had this error on and off for around two years in a several XLSM files (which is most annoying as when it occurs there is nothing wrong with the file! - I suspect orphaned Excel processes are part of the problem)

The most efficient solution I had found has been to use Python with oletools https://github.com/decalage2/oletools/wiki/Install and extract the VBA code all the modules and save in a text file.

Then I simply rename the file to zip file (backup just in case!), open up this zip file and delete the xl/vbaProject.bin file. Rename back to XLSX and should be good to go.

Copy in the saved VBA code (which will need cleaning of line breaks, comments and other stuff. Will also need to add in missing libraries.

This has saved me when other methods haven't.

YMMV.

What causes a java.lang.StackOverflowError

I created a program with hibernate, in which I created two POJO classes, both with an object of each other as data members. When in the main method I tried to save them in the database I also got this error.

This happens because both of the classes are referring each other, hence creating a loop which causes this error.

So, check whether any such kind of relationships exist in your program.

Line break in SSRS expression

You Can Use This One

="Line 1" & "<br>" & "Line 2"

How to use PHP string in mySQL LIKE query?

You have the syntax wrong; there is no need to place a period inside a double-quoted string. Instead, it should be more like

$query = mysql_query("SELECT * FROM table WHERE the_number LIKE '$prefix%'");

You can confirm this by printing out the string to see that it turns out identical to the first case.

Of course it's not a good idea to simply inject variables into the query string like this because of the danger of SQL injection. At the very least you should manually escape the contents of the variable with mysql_real_escape_string, which would make it look perhaps like this:

$sql = sprintf("SELECT * FROM table WHERE the_number LIKE '%s%%'",
               mysql_real_escape_string($prefix));
$query = mysql_query($sql);

Note that inside the first argument of sprintf the percent sign needs to be doubled to end up appearing once in the result.

Choosing a jQuery datagrid plugin?

You should look here: https://stackoverflow.com/questions/159025/jquery-grid-recommendations

Update

The link above takes to a question that was closed and then deleted. Here are the original suggestions that were on the most voted answer:

MVC which submit button has been pressed

In Core 2.2 Razor pages this syntax works:

    <button type="submit" name="Submit">Save</button>
    <button type="submit" name="Cancel">Cancel</button>
public async Task<IActionResult> OnPostAsync()
{
    if (!ModelState.IsValid)
        return Page();
    var sub = Request.Form["Submit"];
    var can = Request.Form["Cancel"];
    if (sub.Count > 0)
       {
       .......

Removing whitespace from strings in Java

There are others space char too exists in strings.. So space char we may need to replace from strings.

Ex: NO-BREAK SPACE, THREE-PER-EM SPACE, PUNCTUATION SPACE

Here is the list of space char http://jkorpela.fi/chars/spaces.html

So we need to modify

\u2004 us for THREE-PER-EM SPACE

s.replaceAll("[\u0020\u2004]","")

How to get the range of occupied cells in excel sheet

Bit old question now, but if somebody is looking for solution this works for me.

using Excel = Microsoft.Office.Interop.Excel;

Excel.ApplicationClass excel = new Excel.ApplicationClass();
Excel.Application app = excel.Application;
Excel.Range all = app.get_Range("A1:H10", Type.Missing);

wampserver doesn't go green - stays orange

If you can't start Wamp anymore right after a Windows update, this is often caused because of Windows that has automatically re-turned on the World Wide Web Publishing Service.

To solve: Click on Start, type Services, click Services, find World Wide Web Publishing Service, double click it, set Startup type to Disabled and click Stop button, OK this dialog and try to restart Wamp.

mysql extract year from date format

try this code:

SELECT YEAR( str_to_date( subdateshow, '%m/%d/%Y' ) ) AS Mydate

How to indent/format a selection of code in Visual Studio Code with Ctrl + Shift + F

For me on windows it was Ctrl+¡ , indent line. It adds a tab at the beggining of each line.

How do I delete an exported environment variable?

Walkthrough of creating and deleting an environment variable in bash:

Test if the DUALCASE variable exists:

el@apollo:~$ env | grep DUALCASE
el@apollo:~$ 

It does not, so create the variable and export it:

el@apollo:~$ DUALCASE=1
el@apollo:~$ export DUALCASE

Check if it is there:

el@apollo:~$ env | grep DUALCASE
DUALCASE=1

It is there. So get rid of it:

el@apollo:~$ unset DUALCASE

Check if it's still there:

el@apollo:~$ env | grep DUALCASE
el@apollo:~$ 

The DUALCASE exported environment variable is deleted.

Extra commands to help clear your local and environment variables:

Unset all local variables back to default on login:

el@apollo:~$ CAN="chuck norris"
el@apollo:~$ set | grep CAN
CAN='chuck norris'
el@apollo:~$ env | grep CAN
el@apollo:~$
el@apollo:~$ exec bash
el@apollo:~$ set | grep CAN
el@apollo:~$ env | grep CAN
el@apollo:~$

exec bash command cleared all the local variables but not environment variables.

Unset all environment variables back to default on login:

el@apollo:~$ export DOGE="so wow"
el@apollo:~$ env | grep DOGE
DOGE=so wow
el@apollo:~$ env -i bash
el@apollo:~$ env | grep DOGE
el@apollo:~$

env -i bash command cleared all the environment variables to default on login.

Detecting touch screen devices with Javascript

if ("ontouchstart" in window || navigator.msMaxTouchPoints) {
    isTouch = true;
} else {
    isTouch = false;
}

Works every where !!

How do you extract a JAR in a UNIX filesystem with a single command and specify its target directory using the JAR command?

Can't you just change working directory within the python script using os.chdir(target)? I agree, I can't see any way of doing it from the jar command itself.

If you don't want to permanently change directory, then store the current directory (using os.getcwd())in a variable and change back afterwards.

Reload a DIV without reloading the whole page

try this

<script type="text/javascript">
window.onload = function(){


var auto_refresh = setInterval(
function ()
{
$('.View').html('');
$('.View').load('Small.php').fadeIn("slow");
}, 15000); // refresh every 15000 milliseconds

}
</script>

Click a button programmatically - JS

When using JavaScript to access an HTML element, there is a good chance that the element is not on the page and therefore not in the dom as far as JavaScript is concerned, when the code to access that element runs.

This problem can occur even though you can visually see the HTML element in the browser window or have the code set to be called in the onload method.

I ran into this problem after writing code to repopulate specific div elements on a page after retrieving the cookies.

What is apparently happening is that even though the HTML has loaded and is outputted by the browser, the JavaScript code is running before the page has completed loading.

The solution to this problem which just may be a JavaScript bug, is to place the code you want to run within a timer that delays the code run by 400 milliseconds or so. You will need to test it to determine how quick you can run the code.

I also made a point to test for the element before attempting to assign values to it.

window.setTimeout(function() { if( document.getElementById("book") ) { // Code goes here }, 400 /* but after 400 ms */);

This may or may not help you solve your problem, but keep this in mind and understand that browsers do not always function as expected.

IE 8: background-size fix

As posted by 'Dan' in a similar thread, there is a possible fix if you're not using a sprite:

How do I make background-size work in IE?

filter: progid:DXImageTransform.Microsoft.AlphaImageLoader(
src='images/logo.gif',
sizingMethod='scale');

-ms-filter: "progid:DXImageTransform.Microsoft.AlphaImageLoader(
src='images/logo.gif',
sizingMethod='scale')";

However, this scales the entire image to fit in the allocated area. So if your using a sprite, this may cause issues.

Caution
The filter has a flaw, any links inside the allocated area are no longer clickable.

"Fade" borders in CSS

How to fade borders with CSS:

<div style="border-style:solid;border-image:linear-gradient(red, transparent) 1;border-bottom:0;">Text</div>

Please excuse the inline styles for the sake of demonstration. The 1 property for the border-image is border-image-slice, and in this case defines the border as a single continuous region.

Source: Gradient Borders

How to add text at the end of each line in Vim?

I have <M-DOWN>(alt down arrow) mapped to <DOWN>. so that I can repeat the last command on a series of lines very quickly. with this mapping I can:

A,<ESC>

And then hold alt while pressing down repeatedly to append the comma to the end of each line.
This works well for me because it allows very good control over what lines do and do not get the change.
(I also have the other arrows mapped similarly to allow for easy repeating of .)

Here's the mapping line to paste into your vimrc:

map <M-DOWN> <DOWN>.

Download pdf file using jquery ajax

For those looking a more modern approach, you can use the fetch API. The following example shows how to download a PDF file. It is easily done with the following code.

fetch(url, {
    body: JSON.stringify(data),
    method: 'POST',
    headers: {
        'Content-Type': 'application/json; charset=utf-8'
    },
})
.then(response => response.blob())
.then(response => {
    const blob = new Blob([response], {type: 'application/pdf'});
    const downloadUrl = URL.createObjectURL(blob);
    const a = document.createElement("a");
    a.href = downloadUrl;
    a.download = "file.pdf";
    document.body.appendChild(a);
    a.click();
})

I believe this approach to be much easier to understand than other XMLHttpRequest solutions. Also, it has a similar syntax to the jQuery approach, without the need to add any additional libraries.

Of course, I would advise checking to which browser you are developing, since this new approach won't work on IE. You can find the full browser compatibility list on the following [link][1].

Important: In this example I am sending a JSON request to a server listening on the given url. This url must be set, on my example I am assuming you know this part. Also, consider the headers needed for your request to work. Since I am sending a JSON, I must add the Content-Type header and set it to application/json; charset=utf-8, as to let the server know the type of request it will receive.

How do I run a program with commandline arguments using GDB within a Bash script?

You could create a file with context:

run arg1 arg2 arg3 etc

program input

And call gdb like

gdb prog < file

Delete rows containing specific strings in R

You could use dplyr::filter() and negate a grepl() match:

library(dplyr)

df %>% 
  filter(!grepl('REVERSE', Name))

Or with dplyr::filter() and negating a stringr::str_detect() match:

library(stringr)

df %>% 
  filter(!str_detect(Name, 'REVERSE'))

Abstract Class vs Interface in C++

interface were primarily made popular by Java.
Below are the nature of interface and its C++ equivalents:

  1. interface can contain only body-less abstract methods; C++ equivalent is pure virtual methods, though they can/cannot have body
  2. interface can contain only static final data members; C++ equivalent is static const data members which are compile time constants
  3. Multiple interface can be implemented by a Java class, this facility is needed because a Java class can inherit only 1 class; C++ supports multiple inheritance straight away with help of virtual keyword when needed

Because of point 3 interface concept was never formally introduced in C++. Still one can have a flexibility to do that.

Besides this you can refer Bjarne's FAQ on this topic.

return SQL table as JSON in python

import sqlite3
import json

DB = "./the_database.db"

def get_all_users( json_str = False ):
    conn = sqlite3.connect( DB )
    conn.row_factory = sqlite3.Row # This enables column access by name: row['column_name'] 
    db = conn.cursor()

    rows = db.execute('''
    SELECT * from Users
    ''').fetchall()

    conn.commit()
    conn.close()

    if json_str:
        return json.dumps( [dict(ix) for ix in rows] ) #CREATE JSON

    return rows

Callin the method no json...

print get_all_users()

prints:

[(1, u'orvar', u'password123'), (2, u'kalle', u'password123')]

Callin the method with json...

print get_all_users( json_str = True )

prints:

[{"password": "password123", "id": 1, "name": "orvar"}, {"password": "password123", "id": 2, "name": "kalle"}]

When to use .First and when to use .FirstOrDefault with LINQ?

This type of the function belongs to element operators. Some useful element operators are defined below.

  1. First/FirstOrDefault
  2. Last/LastOrDefault
  3. Single/SingleOrDefault

We use element operators when we need to select a single element from a sequence based on a certain condition. Here is an example.

  List<int> items = new List<int>() { 8, 5, 2, 4, 2, 6, 9, 2, 10 };

First() operator returns the first element of a sequence after satisfied the condition. If no element is found then it will throw an exception.

int result = items.Where(item => item == 2).First();

FirstOrDefault() operator returns the first element of a sequence after satisfied the condition. If no element is found then it will return default value of that type.

int result1 = items.Where(item => item == 2).FirstOrDefault();

How to pass variable from jade template file to a script file?

#{} is for escaped string interpolation which automatically escapes the input and is thus more suitable for plain strings rather than JS objects:

script var data = #{JSON.stringify(data)}
<script>var data = {&quot;foo&quot;:&quot;bar&quot;} </script>

!{} is for unescaped code interpolation, which is more suitable for objects:

script var data = !{JSON.stringify(data)}
<script>var data = {"foo":"bar"} </script>

CAUTION: Unescaped code can be dangerous. You must be sure to sanitize any user inputs to avoid cross-site scripting (XSS).

E.g.:

{ foo: 'bar </script><script> alert("xss") //' }

will become:

<script>var data = {"foo":"bar </script><script> alert("xss") //"}</script>

Possible solution: Use .replace(/<\//g, '<\\/')

script var data = !{JSON.stringify(data).replace(/<\//g, '<\\/')}
<script>var data = {"foo":"bar<\/script><script>alert(\"xss\")//"}</script>

The idea is to prevent the attacker to:

  1. Break out of the variable: JSON.stringify escapes the quotes
  2. Break out of the script tag: if the variable contents (which you might not be able to control if comes from the database for ex.) has a </script> string, the replace statement will take care of it

https://github.com/pugjs/pug/blob/355d3dae/examples/dynamicscript.pug

How to scanf only integer and repeat reading if the user enters non-numeric characters?

char check1[10], check2[10];
int foo;

do{
  printf(">> ");
  scanf(" %s", check1);
  foo = strtol(check1, NULL, 10); // convert the string to decimal number
  sprintf(check2, "%d", foo); // re-convert "foo" to string for comparison
} while (!(strcmp(check1, check2) == 0 && 0 < foo && foo < 24)); // repeat if the input is not number

If the input is number, you can use foo as your input.

How to check if type of a variable is string?

you can do:

var = 1
if type(var) == int:
   print('your variable is an integer')

or:

var2 = 'this is variable #2'
if type(var2) == str:
    print('your variable is a string')
else:
    print('your variable IS NOT a string')

hope this helps!

Scrollview vertical and horizontal in android

since the Two Dimensional Scrollview link is dead I could not get it so I created my own component. It handles flinging and works properly for me. The only restriction is that wrap_content might not work properly for that component.

https://gist.github.com/androidseb/9902093

How do I convert an enum to a list in C#?

Language[] result = (Language[])Enum.GetValues(typeof(Language))

Android: failed to convert @drawable/picture into a drawable

It can be even more trivial than what the other posters suggested: if you have multiple projects make sure you did not create the xml layout file in the wrong project.

After creation, the file will open automatically so this might go unnoticed and you assume it is in the correct project. Obviously any references to drawables or other resources will be invalid.

And yes, I am that stupid. I'll close any unused projects from now on :)

Hadoop/Hive : Loading data from .csv on a local machine

You can load local CSV file to Hive only if:

  1. You are doing it from one of the Hive cluster nodes.
  2. You installed Hive client on non-cluster node and using hive or beeline for upload.

Spring Boot: Unable to start EmbeddedWebApplicationContext due to missing EmbeddedServletContainerFactory bean

This should be caused by dependency issue, in general, you need to check the dependency.

Returning a file to View/Download in ASP.NET MVC

Darin Dimitrov's answer is correct. Just an addition:

Response.AppendHeader("Content-Disposition", cd.ToString()); may cause the browser to fail rendering the file if your response already contains a "Content-Disposition" header. In that case, you may want to use:

Response.Headers.Add("Content-Disposition", cd.ToString());

What's the best way to determine which version of Oracle client I'm running?

In Windows -> use Command Promt:

tnsping localhost

It show the version and if is installed 32 o 64 bit client, for example:

TNS Ping Utility for 64-bit Windows: Version 10.2.0.4.0 - Production on 03-MAR-2015 16:47:26

Source: https://decipherinfosys.wordpress.com/2007/02/10/checking-for-oracle-client-version-on-windows/

SQL Server - INNER JOIN WITH DISTINCT

add "distinct" after "select".

select distinct a.FirstName, a.LastName, v.District , v.LastName
from AddTbl a 
inner join ValTbl v  where a.LastName = v.LastName  order by Firstname

jQuery validation: change default error message

I never thought this would be so easy , I was working on a project to handle such validation.

The below answer will of great help to one who want to change validation message without much effort.

The below approaches uses the "Placeholder name" in place of "This Field".

You can easily modify things

   // Jquery Validation   
   $('.js-validation').each(function(){

       //Validation Error Messages 

       var validationObjectArray = [];

       var validationMessages = {};

       $(this).find('input,select').each(function(){  // add more type hear

          var singleElementMessages = {};

          var fieldName = $(this).attr('name');

          if(!fieldName){  //field Name is not defined continue ;
              return true;
          }


          // If attr data-error-field-name is given give it a priority , and then to placeholder and lastly a simple text

          var fieldPlaceholderName = $(this).data('error-field-name') || $(this).attr('placeholder') || "This Field";

          if( $( this ).prop( 'required' )){

              singleElementMessages['required'] = $(this).data('error-required-message') || $(this).data('error-message')  || fieldPlaceholderName + " is required";

          }

          if( $( this ).attr( 'type' ) == 'email' ){

              singleElementMessages['email'] = $(this).data('error-email-message') || $(this).data('error-message')  || "Enter valid email in "+fieldPlaceholderName;

          }       



          validationMessages[fieldName] = singleElementMessages;

       });


       $(this).validate({
          errorClass   : "error-message",
          errorElement : "div",
          messages     : validationMessages  
       });  
   });  

Jenkins - how to build a specific branch

I can see many good answers to the question, but I still would like to share this method, by using Git parameter as follows:

Add Git parameter

When building the pipeline you will be asked to choose the branch: Choose branch to build

After that through the groovy code you could specify the branch you want to clone:

git branch:BRANCH[7..-1], url: 'https://github.com/YourName/YourRepo.git' , credentialsId: 'github' 

Note that I'm using a slice from 7 to the last character to shrink "origin/" and get the branch name.

Also in case you configured a webhooks trigger it still work and it will take the default branch you specified(master in our case).

Cannot read property 'push' of undefined when combining arrays

I fixed in the below way with typescript

  1. Define and initialize firest

pageNumbers: number[] = [];

  1. than populate it

    for (let i = 1; i < 201; i++) {
        this.pageNumbers.push(i);
    }
    

How to read a list of files from a folder using PHP?

Check in many folders :

Folder_1 and folder_2 are name of folders, from which we have to select files.

$format is required format.

<?php
$arr = array("folder_1","folder_2");
$format  = ".csv";

for($x=0;$x<count($arr);$x++){
    $mm = $arr[$x];

    foreach (glob("$mm/*$format") as $filename) {
        echo "$filename size " . filesize($filename) . "<br>";
    }
}
?>

How to execute Python code from within Visual Studio Code

There is a much easier way to run Python, and it doesn't need any configuration:

  1. Install the Code Runner Extension.
  2. Open the Python code file in Text Editor.
  3. To run Python code:
  • use shortcut Ctrl + Alt + N
  • or press F1 and then select/type Run Code,
  • or right click the Text Editor and then click Run Code in the editor context menu
  • or click the Run Code button in the editor title menu
  • or click Run Code button in the context menu of file explorer
  1. To stop the running code:
  • use shortcut Ctrl + Alt + M
  • or press F1 and then select/type Stop Code Run
  • or right click the Output Channel and then click Stop Code Run in the context menu

Run Python

If you want to add the Python path, you could go to File ? Preference ? Settings, and add the Python path like below:

"code-runner.executorMap":
{
  "python": "\"C:\\Program Files\\Python35\\python.exe\" -u"
}

In case you have installed the Python extension and manually set your interpreter already, you could configure your settings.json file as follows:

{
    "python.pythonPath": "C:\\\\python36\\\\python36.exe",
    "code-runner.executorMap":
    {
        "python": "$pythonPath -u $fullFileName"
    }
}

What is the strict aliasing rule?

Type punning via pointer casts (as opposed to using a union) is a major example of breaking strict aliasing.

Is this very likely to create a memory leak in Tomcat?

I added the following to @PreDestroy method in my CDI @ApplicationScoped bean, and when I shutdown TomEE 1.6.0 (tomcat7.0.39, as of today), it clears the thread locals.

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package pf;

import java.lang.ref.WeakReference;
import java.lang.reflect.Array;
import java.lang.reflect.Field;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 *
 * @author Administrator
 * 
 * google-gson issue # 402: Memory Leak in web application; comment # 25
 * https://code.google.com/p/google-gson/issues/detail?id=402
 */
public class ThreadLocalImmolater {

    final Logger logger = LoggerFactory.getLogger(ThreadLocalImmolater.class);

    Boolean debug;

    public ThreadLocalImmolater() {
        debug = true;
    }

    public Integer immolate() {
        int count = 0;
        try {
            final Field threadLocalsField = Thread.class.getDeclaredField("threadLocals");
            threadLocalsField.setAccessible(true);
            final Field inheritableThreadLocalsField = Thread.class.getDeclaredField("inheritableThreadLocals");
            inheritableThreadLocalsField.setAccessible(true);
            for (final Thread thread : Thread.getAllStackTraces().keySet()) {
                    count += clear(threadLocalsField.get(thread));
                    count += clear(inheritableThreadLocalsField.get(thread));
            }
            logger.info("immolated " + count + " values in ThreadLocals");
        } catch (Exception e) {
            throw new Error("ThreadLocalImmolater.immolate()", e);
        }
        return count;
    }

    private int clear(final Object threadLocalMap) throws Exception {
        if (threadLocalMap == null)
                return 0;
        int count = 0;
        final Field tableField = threadLocalMap.getClass().getDeclaredField("table");
        tableField.setAccessible(true);
        final Object table = tableField.get(threadLocalMap);
        for (int i = 0, length = Array.getLength(table); i < length; ++i) {
            final Object entry = Array.get(table, i);
            if (entry != null) {
                final Object threadLocal = ((WeakReference)entry).get();
                if (threadLocal != null) {
                    log(i, threadLocal);
                    Array.set(table, i, null);
                    ++count;
                }
            }
        }
        return count;
    }

    private void log(int i, final Object threadLocal) {
        if (!debug) {
            return;
        }
        if (threadLocal.getClass() != null &&
            threadLocal.getClass().getEnclosingClass() != null &&
            threadLocal.getClass().getEnclosingClass().getName() != null) {

            logger.info("threadLocalMap(" + i + "): " +
                        threadLocal.getClass().getEnclosingClass().getName());
        }
        else if (threadLocal.getClass() != null &&
                 threadLocal.getClass().getName() != null) {
            logger.info("threadLocalMap(" + i + "): " + threadLocal.getClass().getName());
        }
        else {
            logger.info("threadLocalMap(" + i + "): cannot identify threadlocal class name");
        }
    }

}

Calling async method synchronously

Microsoft Identity has extension methods which call async methods synchronously. For example there is GenerateUserIdentityAsync() method and equal CreateIdentity()

If you look at UserManagerExtensions.CreateIdentity() it look like this:

 public static ClaimsIdentity CreateIdentity<TUser, TKey>(this UserManager<TUser, TKey> manager, TUser user,
        string authenticationType)
        where TKey : IEquatable<TKey>
        where TUser : class, IUser<TKey>
    {
        if (manager == null)
        {
            throw new ArgumentNullException("manager");
        }
        return AsyncHelper.RunSync(() => manager.CreateIdentityAsync(user, authenticationType));
    }

Now lets see what AsyncHelper.RunSync does

  public static TResult RunSync<TResult>(Func<Task<TResult>> func)
    {
        var cultureUi = CultureInfo.CurrentUICulture;
        var culture = CultureInfo.CurrentCulture;
        return _myTaskFactory.StartNew(() =>
        {
            Thread.CurrentThread.CurrentCulture = culture;
            Thread.CurrentThread.CurrentUICulture = cultureUi;
            return func();
        }).Unwrap().GetAwaiter().GetResult();
    }

So, this is your wrapper for async method. And please don't read data from Result - it will potentially block your code in ASP.

There is another way - which is suspicious for me, but you can consider it too

  Result r = null;

            YourAsyncMethod()
                .ContinueWith(t =>
                {
                    r = t.Result;
                })
                .Wait();

MySQL: Set user variable from result of query

First lets take a look at how can we define a variable in mysql

To define a varible in mysql it should start with '@' like @{variable_name} and this '{variable_name}', we can replace it with our variable name.

Now, how to assign a value in a variable in mysql. For this we have many ways to do that

  1. Using keyword 'SET'.

Example :-

mysql >  SET @a = 1;
  1. Without using keyword 'SET' and using ':='.

Example:-

mysql > @a:=1;
  1. By using 'SELECT' statement.

Example:-

mysql > select 1 into @a;

Here @a is user defined variable and 1 is going to be assigned in @a.

Now how to get or select the value of @{variable_name}.

we can use select statement like

Example :-

mysql > select @a;

it will show the output and show the value of @a.

Now how to assign a value from a table in a variable.

For this we can use two statement like :-

1.

@a := (select emp_name from employee where emp_id = 1);
select emp_name into @a from employee where emp_id = 1;

Always be careful emp_name must return single value otherwise it will throw you a error in this type statements.

refer this:- http://www.easysolutionweb.com/sql-pl-sql/how-to-assign-a-value-in-a-variable-in-mysql

How to set column header text for specific column in Datagridview C#

private void datagrid_ColumnHeaderMouseClick(object sender, DataGridViewCellMouseEventArgs e)
{
    string test = this.datagrid.Columns[e.ColumnIndex].HeaderText;
}

This code will get the HeaderText value.

How do I get a HttpServletRequest in my spring beans?

@eeezyy's answer didn't work for me, although I'm using Spring Boot (2.0.4) and it may differ, but a variation here in 2018 works thus:

@Autowired
private HttpServletRequest request;

Hide Twitter Bootstrap nav collapse on click

I just replicate the 2 attributes of the btn-navbar (data-toggle="collapse" data-target=".nav-collapse.in") on each link like this:

<div class="nav-collapse">
  <ul class="nav" >
    <li class="active"><a href="#home" data-toggle="collapse" data-target=".nav-collapse.in">Home</a></li>
    <li><a href="#about" data-toggle="collapse" data-target=".nav-collapse.in">About</a></li>
    <li><a href="#portfolio" data-toggle="collapse" data-target=".nav-collapse.in">Portfolio</a></li>
    <li><a href="#services" data-toggle="collapse" data-target=".nav-collapse.in">Services</a></li>
    <li><a href="#contact" data-toggle="collapse" data-target=".nav-collapse.in">Contact</a></li>
  </ul>
</div>

In the Bootstrap 4 Navbar, in has changed to show so the syntax would be:

data-toggle="collapse" data-target=".navbar-collapse.show"

How to open Atom editor from command line in OS X?

Iv'e noticed this recently with all new macs here at my office. Atom will be installed via an image for the developers but we found the Atom is never in the Application folder.

When doing a ls on the /usr/local/bin folder the path for atom will show something like "/private/var/folders/cs" . To resolve this, we just located atom.app and copied it into the application folder, then ran the system link commands provided by nwinkler which resoled the issue. Developers can now open atom from the command line with "atom" or open the current projects from their working director with "atom ."

python 2 instead of python 3 as the (temporary) default python?

mkdir ~/bin
PATH=~/bin:$PATH
ln -s /usr/bin/python2 ~/bin/python

To stop using python2, exit or rm ~/bin/python.

how to kill the tty in unix

The simplest way is with the pkill command. In your case:

pkill -9 -t pts/6
pkill -9 -t pts/9
pkill -9 -t pts/10

Regarding tty sessions, the commands below are always useful:

w - shows active terminal sessions

tty - shows your current terminal session (so you won't close it by accident)

last | grep logged - shows currently logged users

Sometimes we want to close all sessions of an idle user (ie. when connections are lost abruptly).

pkill -u username - kills all sessions of 'username' user.

And sometimes when we want to kill all our own sessions except the current one, so I made a script for it. There are some cosmetics and some interactivity (to avoid accidental running on the script).

#!/bin/bash
MYUSER=`whoami`
MYSESSION=`tty | cut -d"/" -f3-`
OTHERSESSIONS=`w $MYUSER | grep "^$MYUSER" | grep -v "$MYSESSION" | cut -d" " -f2`
printf "\e[33mCurrent session\e[0m: $MYUSER[$MYSESSION]\n"

if [[ ! -z $OTHERSESSIONS ]]; then
  printf "\e[33mOther sessions:\e[0m\n"
  w $MYUSER | egrep "LOGIN@|^$MYUSER" | grep -v "$MYSESSION" | column -t
  echo ----------
  read -p "Do you want to force close all your other sessions? [Y]Yes/[N]No: " answer
  answer=`echo $answer | tr A-Z a-z`
  confirm=("y" "yes")

  if [[ "${confirm[@]}" =~ "$answer" ]]; then
  for SESSION in $OTHERSESSIONS
    do
         pkill -9 -t $SESSION
         echo Session $SESSION closed.
    done
  fi
else
        echo "There are no other sessions for the user '$MYUSER'".
fi

Mysql service is missing

I came across the same problem. I properly installed the MYSQL Workbench 6.x, but faced the connection as below:

enter image description here

I did a bit R&D on this and found that MySQL service in service.msc is not present. To achieve this I created a new connection in MySQL Workbench then manually configured the MySQL Database Server in "System Profile" (see the below picture).

You also need to install MySQL Database Server and set a configuration file path for my.ini. Now at last test the connection (make sure MySQL service is running in services.msc).

enter image description here

Unable to start MySQL server

I solved it by open a command prompt as an administrator and point to mysql folder -> bin -> mysql.exe. it works

How to check if input date is equal to today's date?

Date.js is a handy library for manipulating and formatting dates. It can help in this situation.

Why do we use $rootScope.$broadcast in AngularJS?

  1. What does $rootScope.$broadcast do?

    $rootScope.$broadcast is sending an event through the application scope. Any children scope of that app can catch it using a simple: $scope.$on().

    It is especially useful to send events when you want to reach a scope that is not a direct parent (A branch of a parent for example)

    !!! One thing to not do however is to use $rootScope.$on from a controller. $rootScope is the application, when your controller is destroyed that event listener will still exist, and when your controller will be created again, it will just pile up more event listeners. (So one broadcast will be caught multiple times). Use $scope.$on() instead, and the listeners will also get destroyed.

  2. What is the difference between $rootScope.$broadcast & $rootScope.$broadcast.apply?

    Sometimes you have to use apply(), especially when working with directives and other JS libraries. However since I don't know that code base, I wouldn't be able to tell if that's the case here.

Make an html number input always display 2 decimal places

an inline solution combines Groot and Ivaylo suggestions in the format below:

onchange="(function(el){el.value=parseFloat(el.value).toFixed(2);})(this)"

Priority queue in .Net

class PriorityQueue<T>
{
    IComparer<T> comparer;
    T[] heap;
    public int Count { get; private set; }
    public PriorityQueue() : this(null) { }
    public PriorityQueue(int capacity) : this(capacity, null) { }
    public PriorityQueue(IComparer<T> comparer) : this(16, comparer) { }
    public PriorityQueue(int capacity, IComparer<T> comparer)
    {
        this.comparer = (comparer == null) ? Comparer<T>.Default : comparer;
        this.heap = new T[capacity];
    }
    public void push(T v)
    {
        if (Count >= heap.Length) Array.Resize(ref heap, Count * 2);
        heap[Count] = v;
        SiftUp(Count++);
    }
    public T pop()
    {
        var v = top();
        heap[0] = heap[--Count];
        if (Count > 0) SiftDown(0);
        return v;
    }
    public T top()
    {
        if (Count > 0) return heap[0];
        throw new InvalidOperationException("??????");
    }
    void SiftUp(int n)
    {
        var v = heap[n];
        for (var n2 = n / 2; n > 0 && comparer.Compare(v, heap[n2]) > 0; n = n2, n2 /= 2) heap[n] = heap[n2];
        heap[n] = v;
    }
    void SiftDown(int n)
    {
        var v = heap[n];
        for (var n2 = n * 2; n2 < Count; n = n2, n2 *= 2)
        {
            if (n2 + 1 < Count && comparer.Compare(heap[n2 + 1], heap[n2]) > 0) n2++;
            if (comparer.Compare(v, heap[n2]) >= 0) break;
            heap[n] = heap[n2];
        }
        heap[n] = v;
    }
}

easy.

html div onclick event

Try out this example, the onclick is still called from your HTML, and event bubbling is stopped.

<div class="expandable-panel-heading">
<h2>
  <a id="ancherComplaint" href="#addComplaint" onclick="markActiveLink(this);event.stopPropagation();">ABC</a>
</h2>
</div>

http://jsfiddle.net/NXML7/1/

count number of rows in a data frame in R based on group

Using the example data set that Ananda dummied up, here's an example using aggregate(), which is part of core R. aggregate() just needs something to count as function of the different values of MONTH-YEAR. In this case, I used VALUE as the thing to count:

aggregate(cbind(count = VALUE) ~ MONTH.YEAR, 
          data = mydf, 
          FUN = function(x){NROW(x)})

which gives you..

  MONTH.YEAR count
1  FEB. 2012     2
2  JAN. 2012     2
3  MAR. 2012     1

How do I set specific environment variables when debugging in Visual Studio?

Starting with NUnit 2.5 you can use /framework switch e.g.:

nunit-console myassembly.dll /framework:net-1.1

This is from NUnit's help pages.

ADB Shell Input Events

By adb shell input keyevent, either an event_code or a string will be sent to the device.

usage: input [text|keyevent]
  input text <string>
  input keyevent <event_code>

Some possible values for event_code are:

0 -->  "KEYCODE_UNKNOWN" 
1 -->  "KEYCODE_MENU" 
2 -->  "KEYCODE_SOFT_RIGHT" 
3 -->  "KEYCODE_HOME" 
4 -->  "KEYCODE_BACK" 
5 -->  "KEYCODE_CALL" 
6 -->  "KEYCODE_ENDCALL" 
7 -->  "KEYCODE_0" 
8 -->  "KEYCODE_1" 
9 -->  "KEYCODE_2" 
10 -->  "KEYCODE_3" 
11 -->  "KEYCODE_4" 
12 -->  "KEYCODE_5" 
13 -->  "KEYCODE_6" 
14 -->  "KEYCODE_7" 
15 -->  "KEYCODE_8" 
16 -->  "KEYCODE_9" 
17 -->  "KEYCODE_STAR" 
18 -->  "KEYCODE_POUND" 
19 -->  "KEYCODE_DPAD_UP" 
20 -->  "KEYCODE_DPAD_DOWN" 
21 -->  "KEYCODE_DPAD_LEFT" 
22 -->  "KEYCODE_DPAD_RIGHT" 
23 -->  "KEYCODE_DPAD_CENTER" 
24 -->  "KEYCODE_VOLUME_UP" 
25 -->  "KEYCODE_VOLUME_DOWN" 
26 -->  "KEYCODE_POWER" 
27 -->  "KEYCODE_CAMERA" 
28 -->  "KEYCODE_CLEAR" 
29 -->  "KEYCODE_A" 
30 -->  "KEYCODE_B" 
31 -->  "KEYCODE_C" 
32 -->  "KEYCODE_D" 
33 -->  "KEYCODE_E" 
34 -->  "KEYCODE_F" 
35 -->  "KEYCODE_G" 
36 -->  "KEYCODE_H" 
37 -->  "KEYCODE_I" 
38 -->  "KEYCODE_J" 
39 -->  "KEYCODE_K" 
40 -->  "KEYCODE_L" 
41 -->  "KEYCODE_M" 
42 -->  "KEYCODE_N" 
43 -->  "KEYCODE_O" 
44 -->  "KEYCODE_P" 
45 -->  "KEYCODE_Q" 
46 -->  "KEYCODE_R" 
47 -->  "KEYCODE_S" 
48 -->  "KEYCODE_T" 
49 -->  "KEYCODE_U" 
50 -->  "KEYCODE_V" 
51 -->  "KEYCODE_W" 
52 -->  "KEYCODE_X" 
53 -->  "KEYCODE_Y" 
54 -->  "KEYCODE_Z" 
55 -->  "KEYCODE_COMMA" 
56 -->  "KEYCODE_PERIOD" 
57 -->  "KEYCODE_ALT_LEFT" 
58 -->  "KEYCODE_ALT_RIGHT" 
59 -->  "KEYCODE_SHIFT_LEFT" 
60 -->  "KEYCODE_SHIFT_RIGHT" 
61 -->  "KEYCODE_TAB" 
62 -->  "KEYCODE_SPACE" 
63 -->  "KEYCODE_SYM" 
64 -->  "KEYCODE_EXPLORER" 
65 -->  "KEYCODE_ENVELOPE" 
66 -->  "KEYCODE_ENTER" 
67 -->  "KEYCODE_DEL" 
68 -->  "KEYCODE_GRAVE" 
69 -->  "KEYCODE_MINUS" 
70 -->  "KEYCODE_EQUALS" 
71 -->  "KEYCODE_LEFT_BRACKET" 
72 -->  "KEYCODE_RIGHT_BRACKET" 
73 -->  "KEYCODE_BACKSLASH" 
74 -->  "KEYCODE_SEMICOLON" 
75 -->  "KEYCODE_APOSTROPHE" 
76 -->  "KEYCODE_SLASH" 
77 -->  "KEYCODE_AT" 
78 -->  "KEYCODE_NUM" 
79 -->  "KEYCODE_HEADSETHOOK" 
80 -->  "KEYCODE_FOCUS" 
81 -->  "KEYCODE_PLUS" 
82 -->  "KEYCODE_MENU" 
83 -->  "KEYCODE_NOTIFICATION" 
84 -->  "KEYCODE_SEARCH" 
85 -->  "TAG_LAST_KEYCODE"

The sendevent utility sends touch or keyboard events, as well as other events for simulating the hardware events. Refer to this article for details: Android, low level shell click on screen.

Convert pandas.Series from dtype object to float, and errors to nans

Use pd.to_numeric with errors='coerce'

# Setup
s = pd.Series(['1', '2', '3', '4', '.'])
s

0    1
1    2
2    3
3    4
4    .
dtype: object

pd.to_numeric(s, errors='coerce')

0    1.0
1    2.0
2    3.0
3    4.0
4    NaN
dtype: float64

If you need the NaNs filled in, use Series.fillna.

pd.to_numeric(s, errors='coerce').fillna(0, downcast='infer')

0    1
1    2
2    3
3    4
4    0
dtype: float64

Note, downcast='infer' will attempt to downcast floats to integers where possible. Remove the argument if you don't want that.

From v0.24+, pandas introduces a Nullable Integer type, which allows integers to coexist with NaNs. If you have integers in your column, you can use

pd.__version__
# '0.24.1'

pd.to_numeric(s, errors='coerce').astype('Int32')

0      1
1      2
2      3
3      4
4    NaN
dtype: Int32

There are other options to choose from as well, read the docs for more.


Extension for DataFrames

If you need to extend this to DataFrames, you will need to apply it to each row. You can do this using DataFrame.apply.

# Setup.
np.random.seed(0)
df = pd.DataFrame({
    'A' : np.random.choice(10, 5), 
    'C' : np.random.choice(10, 5), 
    'B' : ['1', '###', '...', 50, '234'], 
    'D' : ['23', '1', '...', '268', '$$']}
)[list('ABCD')]
df

   A    B  C    D
0  5    1  9   23
1  0  ###  3    1
2  3  ...  5  ...
3  3   50  2  268
4  7  234  4   $$

df.dtypes

A     int64
B    object
C     int64
D    object
dtype: object

df2 = df.apply(pd.to_numeric, errors='coerce')
df2

   A      B  C      D
0  5    1.0  9   23.0
1  0    NaN  3    1.0
2  3    NaN  5    NaN
3  3   50.0  2  268.0
4  7  234.0  4    NaN

df2.dtypes

A      int64
B    float64
C      int64
D    float64
dtype: object

You can also do this with DataFrame.transform; although my tests indicate this is marginally slower:

df.transform(pd.to_numeric, errors='coerce')

   A      B  C      D
0  5    1.0  9   23.0
1  0    NaN  3    1.0
2  3    NaN  5    NaN
3  3   50.0  2  268.0
4  7  234.0  4    NaN

If you have many columns (numeric; non-numeric), you can make this a little more performant by applying pd.to_numeric on the non-numeric columns only.

df.dtypes.eq(object)

A    False
B     True
C    False
D     True
dtype: bool

cols = df.columns[df.dtypes.eq(object)]
# Actually, `cols` can be any list of columns you need to convert.
cols
# Index(['B', 'D'], dtype='object')

df[cols] = df[cols].apply(pd.to_numeric, errors='coerce')
# Alternatively,
# for c in cols:
#     df[c] = pd.to_numeric(df[c], errors='coerce')

df

   A      B  C      D
0  5    1.0  9   23.0
1  0    NaN  3    1.0
2  3    NaN  5    NaN
3  3   50.0  2  268.0
4  7  234.0  4    NaN

Applying pd.to_numeric along the columns (i.e., axis=0, the default) should be slightly faster for long DataFrames.

Pointers, smart pointers or shared pointers?

Smart pointers will clean themselves up after they go out of scope (thereby removing fear of most memory leaks). Shared pointers are smart pointers that keep a count of how many instances of the pointer exist, and only clean up the memory when the count reaches zero. In general, only use shared pointers (but be sure to use the correct kind--there is a different one for arrays). They have a lot to do with RAII.

How can I change the size of a Bootstrap checkbox?

It is possible in css, but not for all the browsers.

The effect on all browsers:

http://www.456bereastreet.com/lab/form_controls/checkboxes/

A possibility is a custom checkbox with javascript:

http://ryanfait.com/resources/custom-checkboxes-and-radio-buttons/

How to return an array from an AJAX call?

Php has a super sexy function for this, just pass the array to it:

$json = json_encode($var);

$.ajax({
url:"Example.php",
type:"POST",
dataType : "json",
success:function(msg){
    console.info(msg);
}
});

simples :)

Changing website favicon dynamically

Here’s some code that works in Firefox, Opera, and Chrome (unlike every other answer posted here). Here is a different demo of code that works in IE11 too. The following example might not work in Safari or Internet Explorer.

/*!
 * Dynamically changing favicons with JavaScript
 * Works in all A-grade browsers except Safari and Internet Explorer
 * Demo: http://mathiasbynens.be/demo/dynamic-favicons
 */

// HTML5™, baby! http://mathiasbynens.be/notes/document-head
document.head = document.head || document.getElementsByTagName('head')[0];

function changeFavicon(src) {
 var link = document.createElement('link'),
     oldLink = document.getElementById('dynamic-favicon');
 link.id = 'dynamic-favicon';
 link.rel = 'shortcut icon';
 link.href = src;
 if (oldLink) {
  document.head.removeChild(oldLink);
 }
 document.head.appendChild(link);
}

You would then use it as follows:

var btn = document.getElementsByTagName('button')[0];
btn.onclick = function() {
 changeFavicon('http://www.google.com/favicon.ico');
};

Fork away or view a demo.

Fixed width buttons with Bootstrap

A block width button could easily become responsive button if the parent container is responsive. I think that using a combination of a fixed width and a more detailed selector path instead of !important because:

1) Its not a hack (setting min-width and max-width the same is however hacky)

2) Does not use the !important tag which is bad practice

3) Uses width so will be very readable and anyone who understands how cascading works in CSS will see whats going on (maybe leave a CSS comment for this?)

4) Combine your selectors that apply to your targeted node for increased accuracy

.parent_element .btn.btn-primary.save-button {
    width: 80px;
}

Parse JSON String to JSON Object in C#.NET

Since you mentioned that you are using Newtonsoft.dll you can convert a JSON string to an object by using its facilities:

MyClass myClass = JsonConvert.DeserializeObject<MyClass>(your_json_string);

[Serializable]
public class MyClass
{
    public string myVar {get; set;}
    etc.
}

Can I force a UITableView to hide the separator between empty cells?

For iOS 7.* and iOS 6.1

The easiest method is to set the tableFooterView property:

- (void)viewDidLoad 
{
    [super viewDidLoad];

    // This will remove extra separators from tableview
    self.tableView.tableFooterView = [[UIView alloc] initWithFrame:CGRectZero];
}

For previous versions

You could add this to your TableViewController (this will work for any number of sections):

- (CGFloat)tableView:(UITableView *)tableView heightForFooterInSection:(NSInteger)section {
     // This will create a "invisible" footer
     return 0.01f;
 }

and if it is not enough, add the following code too:

- (UIView *)tableView:(UITableView *)tableView viewForFooterInSection:(NSInteger)section
{        
    return [UIView new];

    // If you are not using ARC:
    // return [[UIView new] autorelease];
}

Automatically plot different colored lines

You could use a colormap such as HSV to generate a set of colors. For example:

cc=hsv(12);
figure; 
hold on;
for i=1:12
    plot([0 1],[0 i],'color',cc(i,:));
end

MATLAB has 13 different named colormaps ('doc colormap' lists them all).

Another option for plotting lines in different colors is to use the LineStyleOrder property; see Defining the Color of Lines for Plotting in the MATLAB documentation for more information.

Uncaught ReferenceError: $ is not defined

Bitten by this once again, missing library source links. Google Hosted Libraries Similar link

How do I consume the JSON POST data in an Express application

For Express v4+

install body-parser from the npm.

$ npm install body-parser

https://www.npmjs.org/package/body-parser#installation

var express    = require('express')
var bodyParser = require('body-parser')

var app = express()

// parse application/json
app.use(bodyParser.json())

app.use(function (req, res, next) {
  console.log(req.body) // populated!
  next()
})

Is it possible to see more than 65536 rows in Excel 2007?

According to this MSDN entry, the limit is 1 million rows. You could be running in compatibility mode, which would limit you to the old standard of 65k. Does your excel say compatibility mode in the title? If so, you can save the file as a new style file under the "save as" menu, or change your default to always use the 2007 file standard.

Start service in Android

I like to make it more dynamic

Class<?> serviceMonitor = MyService.class; 


private void startMyService() { context.startService(new Intent(context, serviceMonitor)); }
private void stopMyService()  { context.stopService(new Intent(context, serviceMonitor));  }

do not forget the Manifest

<service android:enabled="true" android:name=".MyService.class" />

Jackson how to transform JsonNode to ArrayNode without casting?

In Java 8 you can do it like this:

import java.util.*;
import java.util.stream.*;

List<JsonNode> datasets = StreamSupport
    .stream(datasets.get("datasets").spliterator(), false)
    .collect(Collectors.toList())

PHP mkdir: Permission denied problem

I know that this thread is old, but perhaps this will help someone, one day.

The problem why PHP says "Permission denied" for mkdir() - wrong url path. So, to fix it, all you need it's to obtain correct path. I did it this way:

<?php

$root = $_SERVER["DOCUMENT_ROOT"];
$dir = $root . '/somefolder/';

if( !file_exists($dir) ) {
    mkdir($dir, 0755, true);
}

?>

Determine path of the executing script

I've made a package for this as of 2020-12-03 available on CRAN called "this.path".

Install it using:

install.packages("this.path")

and then use it by:

this.path::this.path()

or

library(this.path)

this.path()

I still have my original answer below, though it is less functional than the version in the package. On a Unix-alike OS, strange characters (such as " ") in the 'Rscript' command-line argument 'file' are replaced (such as "~+~"). R does this so that it is easier to use that filename for other system commands, but this isn't what we want. Given that we want a path usable in R, any such strange character sequences must be replaced.

Original Answer:

My answer is an improvement upon Jerry T's answer. The issue I found is that he is guessing whether a source call was made by checking if variable ofile is found in the first frame on the stack. This will not work with nested source calls, nor source calls made from a non-global environment. Additionally, a source call must be looked for before checking the command-line arguments, that has also been fixed. Here is my solution:

this.path <- function (verbose = getOption("verbose"))
{
    where <- function(x) if (verbose)
        cat("Source: ", x, "\n", sep = "")


    # loop through functions that lead here from most recent to earliest looking
    #     for an appropriate source call (a call to function base::source or base::sys.source)
    # an appropriate source call is a source call in which
    #     argument 'file' has been evaluated (forced)
    # this means, for example, the following is an inappropriate source call:
    #     source(this.path())
    # the argument 'file' is stored as a promise
    #     containing the expression "this.path()"
    # when the value of 'file' is requested, it assigns the value
    #     returned by evaluating "this.path()" to variable 'file'
    # there are two functions on the calling stack at
    #     this point being 'source' and 'this.path'
    # clearly, you don't want to request the 'file' argument from that source
    #     call because the value of 'file' is under evaluation right now!
    # the trick is to ask if variable ('ofile' for base::source, 'exprs' for base::sys.source)
    #     exists in that function's evaluation environment. this is because that
    #     variable is created AFTER argument 'file' has been forced
    # if that variable does exist, then argument 'file' has been forced and the
    #     source call is deemed appropriate. For base::source, the filename we want
    #     is the variable 'ofile' from that function's evaluation environment. For
    #     base::sys.source, the filename we want is the variable 'file' from that
    #     function's evaluation environment.
    # if that variable does NOT exist, then argument 'file' hasn't been forced and
    #     the source call is deemed inappropriate. The 'for' loop moves to the next
    #     function up the calling stack (if available)
    #
    # unfortunately, there is no way to check the argument 'fileName' has been forced
    #     for 'debugSource' since all the work is done internally in C. Instead,
    #     we have to use a 'tryCatch' statement. When we ask for an object by name
    #     using 'get', R is capable of realizing if a variable is asking for its
    #     own definition (a recursive definition). The exact error is "promise already
    #     under evaluation" which indicates that the promise evaluation is requesting
    #     its own value. So we use the 'tryCatch' to get the argument 'fileName'
    #     from the evaluation environment of 'debugSource', and if it does not raise
    #     an error, then we are safe to return that value. If not, the condition
    #     returns false and the 'for' loop moves to the next function up the calling
    #     stack (if available)


    if (.Platform$GUI == "RStudio")
        dbs <- get("debugSource", mode = "function", "tools:rstudio",
            inherits = FALSE)
    for (n in seq.int(sys.nframe(), 1L)[-1L]) {
        if (identical(sys.function(n), base::source) &&
            exists("ofile", envir = sys.frame(n), inherits = FALSE)) {
            path <- get("ofile", envir = sys.frame(n), inherits = FALSE)
            if (!is.character(path))
                path <- summary.connection(path)$description
            where("call to function source")
            return(normalizePath(path, mustWork = TRUE))
        }
        else if (identical(sys.function(n), base::sys.source) &&
            exists("exprs", envir = sys.frame(n), inherits = FALSE)) {
            path <- get("file", envir = sys.frame(n), inherits = FALSE)
            where("call to function sys.source")
            return(normalizePath(path, mustWork = TRUE))
        }
        else if (.Platform$GUI == "RStudio" && identical(sys.function(n), dbs) &&
            tryCatch({
                path <- get("fileName", envir = sys.frame(n), inherits = FALSE)
                TRUE
            }, error = function(c) {
                FALSE
            })) {
            where("call to function debugSource in RStudio")
            return(normalizePath(path, mustWork = TRUE))
        }
    }


    # if the for loop is passed, no appropriate
    #     source call was found up the calling stack
    # next, check if the user is running R from the command-line
    #     on a Windows OS, the GUI is "RTerm"
    #     on a Unix    OS, the GUI is "X11"


    if (.Platform$OS.type == "windows" && .Platform$GUI == "RTerm" ||  # running from Windows command-line
        .Platform$OS.type == "unix" && .Platform$GUI == "X11") {       # running from Unix command-line


        # get all command-line arguments that start with "--file="
        # check the number of command-line arguments starting with "--file="
        #     in case more or less than one were supplied


        path <- grep("^--file=", commandArgs(), value = TRUE)
        if (length(path) == 1L) {
            path <- sub("^--file=", "", path)
            where("Command-line argument 'file'")
            return(normalizePath(path, mustWork = TRUE))
        }
        else if (length(path)) {
            stop("'this.path' used in an inappropriate fashion\n",
                "* no appropriate source call was found up the calling stack\n",
                "* R is being run from the command-line and formal argument \"--file=\" matched by multiple actual arguments\n")
        }
        else stop("'this.path' used in an inappropriate fashion\n",
            "* no appropriate source call was found up the calling stack\n",
            "* R is being run from the command-line and argument \"--file=\" is missing\n")
    }
    else if (.Platform$GUI == "RStudio") {  # running R from 'RStudio'


        # function ".rs.api.getActiveDocumentContext" from the environment "tools:rstudio"
        #     returns a list of information about the document where your cursor is located
        #
        # function ".rs.api.getSourceEditorContext" from the environment "tools:rstudio"
        #     returns a list of information about the document open in the current tab
        #
        # element 'id' is a character string, an identification for the document
        # element 'path' is a character string, the path of the document


        adc <- get(".rs.api.getActiveDocumentContext",
            mode = "function", "tools:rstudio", inherits = FALSE)()
        if (adc$id != "#console") {
            path <- adc$path
            if (nzchar(path)) {
                where("active document in RStudio")
                return(normalizePath(path, mustWork = TRUE))
            }
            else stop("'this.path' used in an inappropriate fashion\n",
                "* no appropriate source call was found up the calling stack\n",
                "* active document in RStudio does not exist\n")
        }


        sec <- get(".rs.api.getSourceEditorContext", mode = "function",
            "tools:rstudio", inherits = FALSE)()
        if (!is.null(sec)) {
            path <- sec$path
            if (nzchar(path)) {
                where("source document in RStudio")
                return(normalizePath(path, mustWork = TRUE))
            }
            else stop("'this.path' used in an inappropriate fashion\n",
                "* no appropriate source call was found up the calling stack\n",
                "* source document in RStudio does not exist\n")
        }
        else stop("'this.path' used in an inappropriate fashion\n",
            "* no appropriate source call was found up the calling stack\n",
            "* R is being run from RStudio with no documents open\n")
    }
    else if (.Platform$OS.type == "windows" && .Platform$GUI == "Rgui") {  # running R from 'RGui' on Windows


        # on a Windows OS only, the function "getWindowsHandles" from the base
        # package "utils" returns a list of external pointers containing the windows
        # handles. The thing of interest are the names of this list, these should
        # be the names of the windows belonging to the current R process. Since
        # RGui can have files besides R scripts open (such as images), a regular
        # expression is used to subset only windows handles with names that exactly
        # match the string "R Console" or end with " - R Editor". I highly suggest
        # that you NEVER end a document's filename with " - R Editor". From there,
        # similar checks are done as in the above section for 'RStudio'


        wh <- names(utils::getWindowsHandles(pattern = "^R Console$| - R Editor$",
            minimized = TRUE))


        if (!length(wh))
            stop("this error SHOULD be unreachable, as far as I know it's impossible to have an R\n",
                "  process running without the R Console open. If you reached this error, please\n",
                "  send a bug report to the package maintainer")


        path <- wh[1L]
        if (path != "R Console") {
            path <- sub(" - R Editor$", "", path)
            if (path != "Untitled") {
                where("active document in RGui")
                return(normalizePath(path, mustWork = TRUE))
            }
            else stop("'this.path' used in an inappropriate fashion\n",
                "* no appropriate source call was found up the calling stack\n",
                "* active document in RGui does not exist\n")
        }


        path <- wh[2L]
        if (!is.na(path)) {
            path <- sub(" - R Editor$", "", path)
            if (path != "Untitled") {
                where("source document in RGui")
                return(normalizePath(path, mustWork = TRUE))
            }
            else stop("'this.path' used in an inappropriate fashion\n",
                "* no appropriate source call was found up the calling stack\n",
                "* source document in RGui does not exist\n")
        }
        else stop("'this.path' used in an inappropriate fashion\n",
            "* no appropriate source call was found up the calling stack\n",
            "* R is being run from RGui with no documents open\n")
    }
    else if (.Platform$OS.type == "unix" && .Platform$GUI == "AQUA") {  # running R from 'RGui' on Unix
        stop("'this.path' used in an inappropriate fashion\n",
            "* no appropriate source call was found up the calling stack\n",
            "* R is being run from AQUA which requires a source call on the calling stack\n")
    }
    else stop("'this.path' used in an inappropriate fashion\n",
        "* no appropriate source call was found up the calling stack\n",
        "* R is being run in an unrecognized manner\n")
}

How merge two objects array in angularjs?

$scope.actions.data.concat is not a function 

same problem with me but i solve the problem by

 $scope.actions.data = [].concat($scope.actions.data , data)

Log4j2 configuration - No log4j2 configuration file found

In my case I had to put it in the bin folder of my project even the fact that my classpath is set to the src folder. I have no idea why, but it's worth a try.

Request Permission for Camera and Library in iOS 10 - Info.plist

You can also request for access programmatically, which I prefer because in most cases you need to know if you took the access or not.

Swift 4 update:

    //Camera
    AVCaptureDevice.requestAccess(for: AVMediaType.video) { response in
        if response {
            //access granted
        } else {

        }
    }

    //Photos
    let photos = PHPhotoLibrary.authorizationStatus()
    if photos == .notDetermined {
        PHPhotoLibrary.requestAuthorization({status in
            if status == .authorized{
                ...
            } else {}
        })
    }

You do not share code so I cannot be sure if this would be useful for you, but general speaking use it as a best practice.

How to detect incoming calls, in an Android device?

Please use the below code. It will help you to get the incoming number with other call details.

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >

<TextView
    android:id="@+id/call"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true"
    android:text="@string/hello_world" />

</RelativeLayout>

MainActivity.java

public class MainActivity extends Activity {

private static final int MISSED_CALL_TYPE = 0;
private TextView txtcall;

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

    txtcall = (TextView) findViewById(R.id.call);

    StringBuffer sb = new StringBuffer();
    Cursor managedCursor = managedQuery(CallLog.Calls.CONTENT_URI, null,
            null, null, null);
    int number = managedCursor.getColumnIndex(CallLog.Calls.NUMBER);
    int type = managedCursor.getColumnIndex(CallLog.Calls.TYPE);
    int date = managedCursor.getColumnIndex(CallLog.Calls.DATE);
    int duration = managedCursor.getColumnIndex(CallLog.Calls.DURATION);
    sb.append("Call Details :");
    while (managedCursor.moveToNext()) {
        String phNumber = managedCursor.getString(number);
        String callType = managedCursor.getString(type);
        String callDate = managedCursor.getString(date);
        Date callDayTime = new Date(Long.valueOf(callDate));
        String callDuration = managedCursor.getString(duration);
        String dir = null;
        int dircode = Integer.parseInt(callType);
        switch (dircode) {

        case CallLog.Calls.OUTGOING_TYPE:
            dir = "OUTGOING";
            break;

        case CallLog.Calls.INCOMING_TYPE:
            dir = "INCOMING";
            break;

        case CallLog.Calls.MISSED_TYPE:
            dir = "MISSED";
            break;
        }
        sb.append("\nPhone Number:--- " + phNumber + " \nCall Type:--- "
                + dir + " \nCall Date:--- " + callDayTime
                + " \nCall duration in sec :--- " + callDuration);
        sb.append("\n----------------------------------");
    }
    managedCursor.close();
    txtcall.setText(sb);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;
}

} 

and in your manifest request for following permissions:

<uses-permission android:name="android.permission.READ_CONTACTS"/>
<uses-permission android:name="android.permission.READ_LOGS"/>

is there a css hack for safari only NOT chrome?

You can use a media-query hack to select Safari 6.1-7.0 from other browsers.

@media \\0 screen {}

Disclaimer: This hack also targets old Chrome versions (before July 2013).

How do I plot only a table in Matplotlib?

You can di this:

#axs[1].plot(clust_data[:,0],clust_data[:,1]) # Remove this if you don't need it
axs[1].axis("off")  # This will leave the table alone in the window 

List file names based on a filename pattern and file content?

It can be done without find as well by using grep's "--include" option.

grep man page says:

--include=GLOB
Search only files whose base name matches GLOB (using wildcard matching as described under --exclude).

So to do a recursive search for a string in a file matching a specific pattern, it will look something like this:

grep -r --include=<pattern> <string> <directory>

For example, to recursively search for string "mytarget" in all Makefiles:

grep -r --include="Makefile" "mytarget" ./

Or to search in all files starting with "Make" in filename:

grep -r --include="Make*" "mytarget" ./

Angular 2 Hover event

yes there is on-mouseover in angular2 instead of ng-Mouseover like in angular 1.x so you have to write this :-

<div on-mouseover='over()' style="height:100px; width:100px; background:#e2e2e2">hello mouseover</div>

over(){
    console.log("Mouseover called");
  }

As @Gunter Suggested in comment there is alternate of on-mouseover we can use this too. Some people prefer the on- prefix alternative, known as the canonical form.

Update

HTML Code -

<div (mouseover)='over()' (mouseout)='out()' style="height:100px; width:100px; background:#e2e2e2">hello mouseover</div>

Controller/.TS Code -

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

@Component({
  selector: 'my-app',
  templateUrl: './app.component.html',
  styleUrls: [ './app.component.css' ]
})
export class AppComponent  {
  name = 'Angular';

  over(){
    console.log("Mouseover called");
  }

  out(){
    console.log("Mouseout called");
  }
}

Working Example

Some other Mouse events can be used in Angular -

(mouseenter)="myMethod()"
(mousedown)="myMethod()"
(mouseup)="myMethod()"

C# Timer or Thread.Sleep

A timer is a better idea, IMO. That way, if your service is asked to stop, it can respond to that very quickly, and just not call the timer tick handler again... if you're sleeping, the service manager will either have to wait 50 seconds or kill your thread, neither of which is terribly nice.

Read values into a shell variable from a pipe

How about this:

echo "hello world" | echo test=$(cat)

What's the best way to store co-ordinates (longitude/latitude, from Google Maps) in SQL Server?

Store both as float, and use unique key words on them.i.em

create table coordinates(
coord_uid counter primary key,
latitude float,
longitude float,
constraint la_long unique(latitude, longitude)
);

Passing multiple variables to another page in url

Your first variable declartion must start with a ? while any additional must be concatenated with a &

How to return a custom object from a Spring Data JPA GROUP BY query

    //in Service      
      `
                public List<DevicesPerCustomer> findDevicesPerCustomer() {
                    LOGGER.info(TAG_NAME + " :: inside findDevicesPerCustomer : ");
                    List<Object[]> list = iDeviceRegistrationRepo.findDevicesPerCustomer();
                    List<DevicesPerCustomer> out = new ArrayList<>();
                    if (list != null && !list.isEmpty()) {
                        DevicesPerCustomer mDevicesPerCustomer = null;
                        for (Object[] object : list) {
                            mDevicesPerCustomer = new DevicesPerCustomer();
mDevicesPerCustomer.setCustomerId(object[0].toString());
                            mDevicesPerCustomer.setCount(Integer.parseInt(object[1].toString()));
                            
                            out.add(mDevicesPerCustomer);
                        }
                    }
            
                    return out;
                }`
        
    //In Repo
        `   @Query(value = "SELECT d.customerId,count(*) FROM senseer.DEVICE_REGISTRATION d  where d.customerId is not null group by d.customerId", nativeQuery=true)
            List<Object[]> findDevicesPerCustomer();`

How do I activate a specific workbook and a specific sheet?

You have to set a reference to the workbook you're opening. Then you can do anything you want with that workbook by using its reference.

Dim wkb As Workbook
Set wkb = Workbooks.Open("Tire.xls") ' open workbook and set reference!

wkb.Sheets("Sheet1").Activate
wkb.Sheets("Sheet1").Cells(2, 1).Value = 123

Could even set a reference to the sheet, which will make life easier later:

Dim wkb As Workbook
Dim sht As Worksheet

Set wkb = Workbooks.Open("Tire.xls")
Set sht = wkb.Sheets("Sheet2")

sht.Activate
sht.Cells(2, 1) = 123

Others have pointed out that .Activate may be superfluous in your case. You don't strictly need to activate a sheet before editing its cells. But, if that's what you want to do, it does no harm to activate -- except for a small hit to performance which should not be noticeable as long as you do it only once or a few times. However, if you activate many times e.g. in a loop, it will slow things down significantly, so activate should be avoided.

How can I convert an HTML table to CSV?

Here's a ruby script that uses nokogiri -- http://nokogiri.rubyforge.org/nokogiri/

require 'nokogiri'

doc = Nokogiri::HTML(table_string)

doc.xpath('//table//tr').each do |row|
  row.xpath('td').each do |cell|
    print '"', cell.text.gsub("\n", ' ').gsub('"', '\"').gsub(/(\s){2,}/m, '\1'), "\", "
  end
  print "\n"
end

Worked for my basic test case.

How can I get the behavior of GNU's readlink -f on a Mac?

A simple one-liner in perl that's sure to work almost everywhere without any external dependencies:

perl -MCwd -e 'print Cwd::abs_path shift' ~/non-absolute/file

Will dereference symlinks.

Usage in a script could be like this:

readlinkf(){ perl -MCwd -e 'print Cwd::abs_path shift' "$1";}
ABSPATH="$(readlinkf ./non-absolute/file)"

How to detect Safari, Chrome, IE, Firefox and Opera browser?

There is also a less "hacky" method which works for all popular browsers. Google has included a browser-check in their Closure Library. In particular, have a look at goog.userAgent and goog.userAgent.product. In this way, you are also up to date if something changes in the way the browsers present themselves (given that you always run the latest version of the closure compiler.)

Git is not working after macOS Update (xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools)

If you created a new Applications folder in an external drive and installed Xcode there:

sudo xcode-select --switch /Volumes/MyExternalStorageName/Applications/Xcode.app/Contents/Developer

Why is it said that "HTTP is a stateless protocol"?

Modern HTTP is stateful. Old timey HTTP was stateless.

Before Netscape invented cookies and HTTPS in 1994 http could be considered stateless. As time progressed more and more stateful aspects were added for a myriad of reasons, including performance and security.

While HTTP 1 originally sought out to be stateless many HTTP/2 components are the very definition of stateful. HTTP/2 abandoned stateless goals.

No reasonable person can read the HTTP/2 RFC and think it is stateless. The errant "HTTP is stateless" old time dogma is false and far from the current reality of stateful HTTP.

Here's a limited, and not exhaustive list, of stateful HTTP/1 and HTTP/2 components:

  • Cookies, named "HTTP State Management Mechanism" by the RFC.
  • HTTPS, which stores keys thus state.
  • HTTP authentication requires state.
  • Web Storage.
  • HTTP caching is stateful.
  • The very purpose of the stream identifier is state. It's even in the name of the RFC section, "Stream States".
  • Header blocks, which establish stream identifiers, are stateful.
  • Frames which reference stream identifiers are stateful.
  • Header Compression, which the HTTP RFC explicitly says is stateful, is stateful.
  • Opportunistic encryption is stateful.

Section 5.1 of the HTTP/2 RFC is a great example of stateful mechanisms defined by the HTTP/2 standard.

Is it safe for web applications to consider HTTP/2 as a stateless protocol?

HTTP/2 is a stateful protocol, but that doesn't mean your HTTP/2 application can't be stateless. You can choose to not use certain stateful features for stateless HTTP/2 applications by using only a subset of HTTP/2 features.

Cookies and some other stateful mechanisms, or less obvious stateful mechanisms, are later HTTP additions. HTTP 1 is said to be stateless although in practice we use standardized stateful mechanisms, like cookies, TLS, and caching. Unlike HTTP/1, HTTP/2 defines stateful components in its standard from the very beginning. A particular HTTP/2 application can use a subset of HTTP/2 features to maintain statelessness, but the protocol itself anticipate state to be the norm, not the exception.

Existing applications, even HTTP 1 applications, needing state will break if trying to use them statelessly. It can be impossible to log into some HTTP/1.1 websites if cookies are disabled, thus breaking the application. It may not be safe to assume that a particular HTTP 1 application does not use state. This is no different for HTTP/2.

Say it with me one last time:

HTTP/2 is a stateful protocol.

How do I copy a version of a single file from one git branch to another?

Run this from the branch where you want the file to end up:

git checkout otherbranch myfile.txt

General formulas:

git checkout <commit_hash> <relative_path_to_file_or_dir>
git checkout <remote_name>/<branch_name> <file_or_dir>

Some notes (from comments):

  • Using the commit hash you can pull files from any commit
  • This works for files and directories
  • overwrites the file myfile.txt and mydir
  • Wildcards don't work, but relative paths do
  • Multiple paths can be specified

an alternative:

git show commit_id:path/to/file > path/to/file

Set color of text in a Textbox/Label to Red and make it bold in asp.net C#

TextBox1.ForeColor = Color.Red;
TextBox1.Font.Bold = True;

Or this can be done using a CssClass (recommended):

.highlight
{
  color:red;
  font-weight:bold;
}

TextBox1.CssClass = "highlight";

Or the styles can be added inline:

TextBox1.Attributes["style"] = "color:red; font-weight:bold;";

Depend on a branch or tag using a git URL in a package.json?

per @dantheta's comment:

As of npm 1.1.65, Github URL can be more concise user/project. npmjs.org/doc/files/package.json.html You can attach the branch like user/project#branch

So

"babel-eslint": "babel/babel-eslint",

Or for tag v1.12.0 on jscs:

"jscs": "jscs-dev/node-jscs#v1.12.0",

Note, if you use npm --save, you'll get the longer git

From https://docs.npmjs.com/cli/v6/configuring-npm/package-json#git-urls-as-dependencies

Git URLs as Dependencies

Git urls are of the form:

git+ssh://[email protected]:npm/cli.git#v1.0.27 git+ssh://[email protected]:npm/cli#semver:^5.0 git+https://[email protected]/npm/cli.git
git://github.com/npm/cli.git#v1.0.27

If #<commit-ish> is provided, it will be used to clone exactly that commit. If > the commit-ish has the format #semver:<semver>, <semver> can be any valid semver range or exact version, and npm will look for any tags or refs matching that range in the remote repository, much as it would for a registry dependency. If neither #<commit-ish> or #semver:<semver> is specified, then master is used.

GitHub URLs

As of version 1.1.65, you can refer to GitHub urls as just "foo": "user/foo-project". Just as with git URLs, a commit-ish suffix can be included. For example:

{
 "name": "foo",
 "version": "0.0.0",
 "dependencies": {
   "express": "expressjs/express",
   "mocha": "mochajs/mocha#4727d357ea",
   "module": "user/repo#feature\/branch"
 }
}```

Put search icon near textbox using bootstrap

<input type="text" name="whatever" id="funkystyling" />

Here's the CSS for the image on the left:

#funkystyling {
    background: white url(/path/to/icon.png) left no-repeat;
    padding-left: 17px;
}

And here's the CSS for the image on the right:

#funkystyling {
    background: white url(/path/to/icon.png) right no-repeat;
    padding-right: 17px;
}

How do I write a custom init for a UIView subclass in Swift?

The init(frame:) version is the default initializer. You must call it only after initializing your instance variables. If this view is being reconstituted from a Nib then your custom initializer will not be called, and instead the init?(coder:) version will be called. Since Swift now requires an implementation of the required init?(coder:), I have updated the example below and changed the let variable declarations to var and optional. In this case, you would initialize them in awakeFromNib() or at some later time.

class TestView : UIView {
    var s: String?
    var i: Int?
    init(s: String, i: Int) {
        self.s = s
        self.i = i
        super.init(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }
}

DropdownList DataSource

protected void Page_Load(object sender, EventArgs e)
{
    if (!Page.IsPostBack)
    {
        drpCategory.DataSource = CategoryHelper.Categories;
        drpCategory.DataTextField = "Name";
        drpCategory.DataValueField = "Id";
        drpCategory.DataBind();
    }
}

getting the screen density programmatically in android?

In Android you can get the screen density like this:

public static String getScreenDensity(Context context)
{
    String density;
    switch (context.getResources().getDisplayMetrics().densityDpi)
    {
        case DisplayMetrics.DENSITY_LOW:
            density = "LDPI";
            break;
        case DisplayMetrics.DENSITY_140:
            density = "LDPI - MDPI";
            break;
        case DisplayMetrics.DENSITY_MEDIUM:
            density = "MDPI";
            break;
        case DisplayMetrics.DENSITY_180:
        case DisplayMetrics.DENSITY_200:
        case DisplayMetrics.DENSITY_220:
            density = "MDPI - HDPI";
            break;
        case DisplayMetrics.DENSITY_HIGH:
            density = "HDPI";
            break;
        case DisplayMetrics.DENSITY_260:
        case DisplayMetrics.DENSITY_280:
        case DisplayMetrics.DENSITY_300:
            density = "HDPI - XHDPI";
            break;
        case DisplayMetrics.DENSITY_XHIGH:
            density = "XHDPI";
            break;
        case DisplayMetrics.DENSITY_340:
        case DisplayMetrics.DENSITY_360:
        case DisplayMetrics.DENSITY_400:
        case DisplayMetrics.DENSITY_420:
        case DisplayMetrics.DENSITY_440:
            density = "XHDPI - XXHDPI";
            break;
        case DisplayMetrics.DENSITY_XXHIGH:
            density = "XXHDPI";
            break;
        case DisplayMetrics.DENSITY_560:
        case DisplayMetrics.DENSITY_600:
            density = "XXHDPI - XXXHDPI";
            break;
        case DisplayMetrics.DENSITY_XXXHIGH:
            density = "XXXHDPI";
            break;
        case DisplayMetrics.DENSITY_TV:
            density = "TVDPI";
            break;
        default:
            density = "UNKNOWN";
            break;
    }

    return density;
}

And in Kotlin like this:

fun getScreenDensity(context: Context): String {
    val density: String
    when (context.resources.displayMetrics.densityDpi) {
        DisplayMetrics.DENSITY_LOW -> density = "LDPI"
        DisplayMetrics.DENSITY_140 -> density = "LDPI - MDPI"
        DisplayMetrics.DENSITY_MEDIUM -> density = "MDPI"
        DisplayMetrics.DENSITY_180, DisplayMetrics.DENSITY_200, DisplayMetrics.DENSITY_220 -> density = "MDPI - HDPI"
        DisplayMetrics.DENSITY_HIGH -> density = "HDPI"
        DisplayMetrics.DENSITY_260, DisplayMetrics.DENSITY_280, DisplayMetrics.DENSITY_300 -> density = "HDPI - XHDPI"
        DisplayMetrics.DENSITY_XHIGH -> density = "XHDPI"
        DisplayMetrics.DENSITY_340, DisplayMetrics.DENSITY_360, DisplayMetrics.DENSITY_400, DisplayMetrics.DENSITY_420, DisplayMetrics.DENSITY_440 -> density =
            "XHDPI - XXHDPI"
        DisplayMetrics.DENSITY_XXHIGH -> density = "XXHDPI"
        DisplayMetrics.DENSITY_560, DisplayMetrics.DENSITY_600 -> density = "XXHDPI - XXXHDPI"
        DisplayMetrics.DENSITY_XXXHIGH -> density = "XXXHDPI"
        DisplayMetrics.DENSITY_TV -> density = "TVDPI"
        else -> density = "UNKNOWN"
    }

    return density
}

Make sure to regularly check if new densities are added.

Using ffmpeg to encode a high quality video

You need to specify the -vb option to increase the video bitrate, otherwise you get the default which produces smaller videos but with more artifacts.

Try something like this:

ffmpeg -r 25 -i %4d.png -vb 20M myvideo.mpg

Pass Method as Parameter using C#

If you want the ability to change which method is called at run time I would recommend using a delegate: http://www.codeproject.com/KB/cs/delegates_step1.aspx

It will allow you to create an object to store the method to call and you can pass that to your other methods when it's needed.

Python - Dimension of Data Frame

df.shape, where df is your DataFrame.

What is the best IDE for C Development / Why use Emacs over an IDE?

How come nobody mentions Bloodshed Devc++? Havent used it in a while, but i learnt c/c++ on it. very similar to MS Visual c++.

Oracle DB: How can I write query ignoring case?

Select * from table where upper(table.name) like upper('IgNoreCaSe');

Alternatively, substitute lower for upper.

Java Multiple Inheritance

May I suggest the concept of Duck-typing?

Most likely you would tend to make the Pegasus extend a Bird and a Horse interface but duck typing actually suggests that you should rather inherit behaviour. As already stated in the comments, a pegasus is not a bird but it can fly. So your Pegasus should rather inherit a Flyable-interface and lets say a Gallopable-interface.

This kind of concept is utilized in the Strategy Pattern. The given example actually shows you how a duck inherits the FlyBehaviour and QuackBehaviour and still there can be ducks, e.g. the RubberDuck, which can't fly. They could have also made the Duck extend a Bird-class but then they would have given up some flexibility, because every Duck would be able to fly, even the poor RubberDuck.

Link error "undefined reference to `__gxx_personality_v0'" and g++

It sounds like you're trying to link with your resulting object file with gcc instead of g++:

Note that programs using C++ object files must always be linked with g++, in order to supply the appropriate C++ libraries. Attempting to link a C++ object file with the C compiler gcc will cause "undefined reference" errors for C++ standard library functions:

$ g++ -Wall -c hello.cc
$ gcc hello.o       (should use g++)
hello.o: In function `main':
hello.o(.text+0x1b): undefined reference to `std::cout'
.....
hello.o(.eh_frame+0x11):
  undefined reference to `__gxx_personality_v0'

Source: An Introduction to GCC - for the GNU compilers gcc and g++

Difference between Select Unique and Select Distinct

Only In Oracle =>

SELECT DISTINCT and SELECT UNIQUE behave the same way. While DISTINCT is ANSI SQL standard, UNIQUE is an Oracle specific statement.

In other databases (like sql-server in your case) =>

SELECT UNIQUE is invalid syntax. UNIQUE is keyword for adding unique constraint on the column.

SELECT DISTINCT

Not Able To Debug App In Android Studio

I also randomly had this problem even after debugging many times in Android Studio. One day the debugger just wouldn't attach. I just had to quit Android Studio and reopen it and the debugger started working again.

django order_by query set, ascending and descending

If for some reason you have null values you can use the F function like this:

from django.db.models import F

Reserved.objects.all().filter(client=client_id).order_by(F('check_in').desc(nulls_last=True))

So it will put last the null values. Documentation by Django: https://docs.djangoproject.com/en/stable/ref/models/expressions/#using-f-to-sort-null-values

How to filter a data frame

You are missing a comma in your statement.

Try this:

data[data[, "Var1"]>10, ]

Or:

data[data$Var1>10, ]

Or:

subset(data, Var1>10)

As an example, try it on the built-in dataset, mtcars

data(mtcars)

mtcars[mtcars[, "mpg"]>25, ]

                mpg cyl  disp  hp drat    wt  qsec vs am gear carb
Fiat 128       32.4   4  78.7  66 4.08 2.200 19.47  1  1    4    1
Honda Civic    30.4   4  75.7  52 4.93 1.615 18.52  1  1    4    2
Toyota Corolla 33.9   4  71.1  65 4.22 1.835 19.90  1  1    4    1
Fiat X1-9      27.3   4  79.0  66 4.08 1.935 18.90  1  1    4    1
Porsche 914-2  26.0   4 120.3  91 4.43 2.140 16.70  0  1    5    2
Lotus Europa   30.4   4  95.1 113 3.77 1.513 16.90  1  1    5    2


mtcars[mtcars$mpg>25, ]

                mpg cyl  disp  hp drat    wt  qsec vs am gear carb
Fiat 128       32.4   4  78.7  66 4.08 2.200 19.47  1  1    4    1
Honda Civic    30.4   4  75.7  52 4.93 1.615 18.52  1  1    4    2
Toyota Corolla 33.9   4  71.1  65 4.22 1.835 19.90  1  1    4    1
Fiat X1-9      27.3   4  79.0  66 4.08 1.935 18.90  1  1    4    1
Porsche 914-2  26.0   4 120.3  91 4.43 2.140 16.70  0  1    5    2
Lotus Europa   30.4   4  95.1 113 3.77 1.513 16.90  1  1    5    2

subset(mtcars, mpg>25)

                mpg cyl  disp  hp drat    wt  qsec vs am gear carb
Fiat 128       32.4   4  78.7  66 4.08 2.200 19.47  1  1    4    1
Honda Civic    30.4   4  75.7  52 4.93 1.615 18.52  1  1    4    2
Toyota Corolla 33.9   4  71.1  65 4.22 1.835 19.90  1  1    4    1
Fiat X1-9      27.3   4  79.0  66 4.08 1.935 18.90  1  1    4    1
Porsche 914-2  26.0   4 120.3  91 4.43 2.140 16.70  0  1    5    2
Lotus Europa   30.4   4  95.1 113 3.77 1.513 16.90  1  1    5    2

How to do select from where x is equal to multiple values?

And even simpler using IN:

SELECT ads.*, location.county 
  FROM ads
  LEFT JOIN location ON location.county = ads.county_id
  WHERE ads.published = 1 
        AND ads.type = 13
        AND ads.county_id IN (2,5,7,9)

Convert float to std::string in C++

This tutorial gives a simple, yet elegant, solution, which i transcribe:

#include <sstream>
#include <string>
#include <stdexcept>

class BadConversion : public std::runtime_error {
public:
  BadConversion(std::string const& s)
    : std::runtime_error(s)
    { }
};

inline std::string stringify(double x)
{
  std::ostringstream o;
  if (!(o << x))
    throw BadConversion("stringify(double)");
  return o.str();
}
...
std::string my_val = stringify(val);

Can I install the "app store" in an IOS simulator?

This is NOT possible

The Simulator does not run ARM code, ONLY x86 code. Unless you have the raw source code from Apple, you won't see the App Store on the Simulator.

The app you write you will be able to test in the Simulator by running it directly from Xcode even if you don't have a developer account. To test your app on an actual device, you will need to be apart of the Apple Developer program.

UnicodeDecodeError: 'ascii' codec can't decode byte 0xd1 in position 2: ordinal not in range(128)

for Python 3 users. you can do

with open(csv_name_here, 'r', encoding="utf-8") as f:
    #some codes

it works with flask too :)

How to measure height, width and distance of object using camera?

If you know the viewport angle of the camera, you can use the height in pixels to determine the angle from the top to bottom of the object. Then, using the distance and arctangent calculate the height:

height = arctan(angle) * distance

To find the viewport angle, point the camera at something which is of known height, and make it exactly fill the screen. For example, point it at a ruler, and make it just far enough away that you can only barely see the ends of the ruler. Measure the distance from the camera, and then your total viewport angle is

viewportAngle = tan(ruler_length / distance)

Then, suppose your camera is 480px tall (cheap webcam), and the view angle is 20°. If you have an object onscreen which is 240px tall, then its angle is 10°. If you know it's 2 feet away, you would say 2 feet * arctan(10°) = ~4.1 inches tall. (I think... it's 2am so this may be a little off)

Center text in div?

Will this work for you?

div { text-align: center; }

Assign null to a SqlParameter

You need pass DBNull.Value as a null parameter within SQLCommand, unless a default value is specified within stored procedure (if you are using stored procedure). The best approach is to assign DBNull.Value for any missing parameter before query execution, and following foreach will do the job.

foreach (SqlParameter parameter in sqlCmd.Parameters)
{
    if (parameter.Value == null)
    {
        parameter.Value = DBNull.Value;
    }
}

Otherwise change this line:

planIndexParameter.Value = (AgeItem.AgeIndex== null) ? DBNull.Value : AgeItem.AgeIndex;

As follows:

if (AgeItem.AgeIndex== null)
    planIndexParameter.Value = DBNull.Value;
else
    planIndexParameter.Value = AgeItem.AgeIndex;

Because you can't use different type of values in conditional statement, as DBNull and int are different from each other. Hope this will help.

Meaning of ${project.basedir} in pom.xml

There are a set of available properties to all Maven projects.

From Introduction to the POM:

project.basedir: The directory that the current project resides in.

This means this points to where your Maven projects resides on your system. It corresponds to the location of the pom.xml file. If your POM is located inside /path/to/project/pom.xml then this property will evaluate to /path/to/project.

Some properties are also inherited from the Super POM, which is the case for project.build.directory. It is the value inside the <project><build><directory> element of the POM. You can get a description of all those values by looking at the Maven model. For project.build.directory, it is:

The directory where all files generated by the build are placed. The default value is target.

This is the directory that will hold every generated file by the build.

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

sleep(3) is in unistd.h, not stdlib.h. Type man 3 sleep on your command line to confirm for your machine, but I presume you're on a Mac since you're learning Objective-C, and on a Mac, you need unistd.h.

Read the package name of an Android APK

A very simple method is to use apkanalyzer.

apkanalyzer manifest application-id "${_path_to_apk}"

javac: invalid target release: 1.8

Just do this. Then invalidate IntelliJ caches (File -> Invalidate Caches)

What is an .inc and why use it?

In my opinion, these were used as a way to quickly find include files when developing. Really these have been made obsolete with conventions and framework designs.

Change the encoding of a file in Visual Studio Code

Apart from the settings explained in the answer by @DarkNeuron:

"files.encoding": "any encoding"

you can also specify settings for a specific language like so:

"[language id]": {
  "files.encoding": "any encoding"
}

For example, I use this when I need to edit PowerShell files previously created with ISE (which are created in ANSI format):

"[powershell]": {
    "files.encoding": "windows1252"
}

You can get a list of identifiers of well-known languages here.

What does bundle exec rake mean?

When you directly run the rake task or execute any binary file of a gem, there is no guarantee that the command will behave as expected. Because it might happen that you already have the same gem installed on your system which have a version say 1.0 but in your project you have higher version say 2.0. In this case you can not predict which one will be used.

To enforce the desired gem version you take the help of bundle exec command which would execute the binary in context of current bundle. That means when you use bundle exec, bundler checks the gem version configured for the current project and use that to perform the task.

I have also written a post about it which also shows how we can avoid using it using bin stubs.

Fastest way(s) to move the cursor on a terminal command line?

One option is to use M-x shell in emacs. That provides all editing facilities and keystrokes that emacs has, so C-s can be used to search the text option25, for example.

(But I'd still prefer to be in the real terminal shell instead if someone can point me to good search and edit facilities.)

How can I include null values in a MIN or MAX?

Use IsNull

SELECT recordid, MIN(startdate), MAX(IsNull(enddate, Getdate()))
FROM tmp 
GROUP BY recordid

I've modified MIN in the second instruction to MAX

jQuery Screen Resolution Height Adjustment

Here is an example on how to center an object vertically with jQuery:

var div= $('#div_SomeDivYouWantToAdjust');
div.css("top", ($(window).height() - div.height())/2  + 'px');

But you could easily change that to whatever your needs are.

how to set start value as "0" in chartjs?

Please add this option:

//Boolean - Whether the scale should start at zero, or an order of magnitude down from the lowest value
scaleBeginAtZero : true,

(Reference: Chart.js)

N.B: The original solution I posted was for Highcharts, if you are not using Highcharts then please remove the tag to avoid confusion

How do I view an older version of an SVN file?

It is also interesting to compare the file of the current working revision with the same file of another revision.

You can do as follows:

$ svn diff -r34 file

What are the uses of "using" in C#?

In conclusion, when you use a local variable of a type that implements IDisposable, always, without exception, use using1.

If you use nonlocal IDisposable variables, then always implement the IDisposable pattern.

Two simple rules, no exception1. Preventing resource leaks otherwise is a real pain in the *ss.


1): The only exception is – when you're handling exceptions. It might then be less code to call Dispose explicitly in the finally block.

Show/hide image with JavaScript

HTML

<img id="theImage" src="yourImage.png">
<a id="showImage">Show image</a>

JavaScript:

document.getElementById("showImage").onclick = function() {
    document.getElementById("theImage").style.display = "block";
}

CSS:

#theImage { display:none; }

Difference between using Throwable and Exception in a try catch

The first one catches all subclasses of Throwable (this includes Exception and Error), the second one catches all subclasses of Exception.

Error is programmatically unrecoverable in any way and is usually not to be caught, except for logging purposes (which passes it through again). Exception is programmatically recoverable. Its subclass RuntimeException indicates a programming error and is usually not to be caught as well.

Python Hexadecimal

I think this is what you want:

>>> def twoDigitHex( number ):
...     return '%02x' % number
... 
>>> twoDigitHex( 2 )
'02'
>>> twoDigitHex( 255 )
'ff'

Best way to find os name and version in Unix/Linux platform

this command gives you a description of your operating system

cat /etc/os-release

How to connect Android app to MySQL database?

Can i use pHp to develop an android app?
Yes . for web development you can use Phonegap. "PHP , HTML"etc.
What are the ways this can be done:?
you can check couple of examples on the internet here is one of them "an easy way" Connect Android To MySQL

iptables v1.4.14: can't initialize iptables table `nat': Table does not exist (do you need to insmod?)

iptalbes tool relies on a kernel module interacting with netfilter to control network traffic.

This error happens while iptalbes cannot found that module in kernel, so iptables suggest you to upgrade it :)

Perhaps iptables or your kernel needs to be upgraded.

However in most cases it's just the module not added to kernel or being banned, try this command to check whether be banned:

cd /etc/modprobe.d/ && grep -nr iptable_nat

if the command shows any rule matched, such as blacklist iptable_nat or install iptable_nat /bin/true, delete it. Since iptalbes will cost some performance, it's not strange to ban it while not necessary.

If nothing found in blacklist, try add iptable-nat to the kernal manual:

modprobe iptable-nat

If all of above not works, you can consider really upgrade your kernal...

Android: Align button to bottom-right of screen using FrameLayout?

It can be achieved using RelativeLayout

<RelativeLayout 
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">

   <ImageView 
      android:src="@drawable/icon"
      android:layout_height="wrap_content"
      android:layout_width="wrap_content"
      android:layout_alignParentRight="true"
      android:layout_alignParentBottom="true" />

</RelativeLayout>