Programs & Examples On #Start process

Start-Process is a powershell cmdlet that starts one or more processes on the local computer.

Capturing standard out and error with Start-Process

That's how Start-Process was designed for some reason. Here's a way to get it without sending to file:

$pinfo = New-Object System.Diagnostics.ProcessStartInfo
$pinfo.FileName = "ping.exe"
$pinfo.RedirectStandardError = $true
$pinfo.RedirectStandardOutput = $true
$pinfo.UseShellExecute = $false
$pinfo.Arguments = "localhost"
$p = New-Object System.Diagnostics.Process
$p.StartInfo = $pinfo
$p.Start() | Out-Null
$p.WaitForExit()
$stdout = $p.StandardOutput.ReadToEnd()
$stderr = $p.StandardError.ReadToEnd()
Write-Host "stdout: $stdout"
Write-Host "stderr: $stderr"
Write-Host "exit code: " + $p.ExitCode

PowerShell - Start-Process and Cmdline Switches

Using explicit parameters, it would be:

$msbuild = 'C:\WINDOWS\Microsoft.NET\Framework\v3.5\MSBuild.exe'
start-Process -FilePath $msbuild -ArgumentList '/v:q','/nologo'

EDIT: quotes.

Git error: src refspec master does not match any

You've created a new repository and added some files to the index, but you haven't created your first commit yet. After you've done:

 git add a_text_file.txt 

... do:

 git commit -m "Initial commit."

... and those errors should go away.

Opening popup windows in HTML

I feel like this is the simplest way. (Feel free to change the width and height values).

<a href="http://www.google.com" 
target="popup" 
onclick="window.open('http://www.google.com','popup','width=600,height=600'); return false;">
Link Text goes here...
</a>

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

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

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

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

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

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

git status shows modifications, git checkout -- <file> doesn't remove them

For future people having this problem: Having filemode changes can also have the same symptoms. git config core.filemode false will fix it.

How can I change column types in Spark SQL's DataFrame?

This method will drop the old column and create new columns with same values and new datatype. My original datatypes when the DataFrame was created were:-

root
 |-- id: integer (nullable = true)
 |-- flag1: string (nullable = true)
 |-- flag2: string (nullable = true)
 |-- name: string (nullable = true)
 |-- flag3: string (nullable = true)

After this I ran following code to change the datatype:-

df=df.withColumnRenamed(<old column name>,<dummy column>) // This was done for both flag1 and flag3
df=df.withColumn(<old column name>,df.col(<dummy column>).cast(<datatype>)).drop(<dummy column>)

After this my result came out to be:-

root
 |-- id: integer (nullable = true)
 |-- flag2: string (nullable = true)
 |-- name: string (nullable = true)
 |-- flag1: boolean (nullable = true)
 |-- flag3: boolean (nullable = true)

What is a vertical tab?

I believe it's still being used, not sure exactly. There might be even a key combination of it.

As English is written Left to Right, Arabic Right to Left, there are languages in world that are also written top to bottom. In that case a vertical tab might be useful same as the horizontal tab is used for English text.

I tried searching, but couldn't find anything useful yet.

Convert interface{} to int

I wrote a library that can help with type convertions https://github.com/KromDaniel/jonson

js := jonson.New([]interface{}{55.6, 70.8, 10.4, 1, "48", "-90"})

js.SliceMap(func(jsn *jonson.JSON, index int) *jonson.JSON {
    jsn.MutateToInt()
    return jsn
}).SliceMap(func(jsn *jonson.JSON, index int) *jonson.JSON {
    if jsn.GetUnsafeInt() > 50{
        jsn.MutateToString()
    }
    return jsn
}) // ["55","70",10,1,48,-90]

Seaborn plots not showing up

My advice is just to give a

plt.figure() and give some sns plot. For example

sns.distplot(data).

Though it will look it doesnt show any plot, When you maximise the figure, you will be able to see the plot.

Is it bad practice to use break to exit a loop in Java?

It isn't bad practice, but it can make code less readable. One useful refactoring to work around this is to move the loop to a separate method, and then use a return statement instead of a break, for example this (example lifted from @Chris's answer):

String item;

for(int x = 0; x < 10; x++)
{
    // Linear search.
    if(array[x].equals("Item I am looking for"))
    {
        //you've found the item. Let's stop.
        item = array[x];
        break; 
    }
}

can be refactored (using extract method) to this:

public String searchForItem(String itemIamLookingFor)
{
    for(int x = 0; x < 10; x++)
    {
        if(array[x].equals(itemIamLookingFor))
        {
            return array[x];
        }
    }
}

Which when called from the surrounding code can prove to be more readable.

How to find Control in TemplateField of GridView?

If your GridView is databond, make an index column in the resultset you retrive like this:

select row_number() over(order by YourIdentityColumn asc)-1 as RowIndex, * from YourTable where [Expresion]

In the command control you want to use make the value of CommandArgument property equal to the row index of the DataSet table RowIndex like this:

<asp:LinkButton ID="lbnMsgSubj" runat="server" Text='<%# Eval("MsgSubj") %>' Font-Underline="false" CommandArgument='<%#Eval("RowIndex") %>' />

Use the OnRowCommand event to fire on clicking the link button like this:

<asp:GridView ID="gvwStuMsgBoard" runat="server" AutoGenerateColumns="false" GridLines="Horizontal" BorderColor="Transparent" Width="100%" OnRowCommand="gvwStuMsgBoard_RowCommand">

Finally the code behind you can then do whatever you like when the event is triggered like this:

protected void gvwStuMsgBoard_RowCommand(object sender, GridViewCommandEventArgs e)
{
    Panel pnlMsgBody = (Panel)gvwStuMsgBoard.Rows[Convert.ToInt32(e.CommandArgument)].FindControl("pnlMsgBody");
    if(pnlMsgBody.Visible == false)
    {
        pnlMsgBody.Visible = true;
    }
    else
    {
        pnlMsgBody.Visible = false;
    }
}

How do I list all the files in a directory and subdirectories in reverse chronological order?

try this:

ls -ltraR |egrep -v '\.$|\.\.|\.:|\.\/|total' |sed '/^$/d'

Where to find the complete definition of off_t type?

If you are writing portable code, the answer is "you can't tell", the good news is that you don't need to. Your protocol should involve writing the size as (eg) "8 octets, big-endian format" (Ideally with a check that the actual size fits in 8 octets.)

When do we need curly braces around shell variables?

The end of the variable name is usually signified by a space or newline. But what if we don't want a space or newline after printing the variable value? The curly braces tell the shell interpreter where the end of the variable name is.

Classic Example 1) - shell variable without trailing whitespace

TIME=10

# WRONG: no such variable called 'TIMEsecs'
echo "Time taken = $TIMEsecs"

# What we want is $TIME followed by "secs" with no whitespace between the two.
echo "Time taken = ${TIME}secs"

Example 2) Java classpath with versioned jars

# WRONG - no such variable LATESTVERSION_src
CLASSPATH=hibernate-$LATESTVERSION_src.zip:hibernate_$LATEST_VERSION.jar

# RIGHT
CLASSPATH=hibernate-${LATESTVERSION}_src.zip:hibernate_$LATEST_VERSION.jar

(Fred's answer already states this but his example is a bit too abstract)

How to create a dotted <hr/> tag?

The <hr> tag is just a short element with a border:

<hr style="border-style: dotted;" />

How to check if all of the following items are in a list?

What if your lists contain duplicates like this:

v1 = ['s', 'h', 'e', 'e', 'p']
v2 = ['s', 's', 'h']

Sets do not contain duplicates. So, the following line returns True.

set(v2).issubset(v1)

To count for duplicates, you can use the code:

v1 = sorted(v1)
v2 = sorted(v2)


def is_subseq(v2, v1):
    """Check whether v2 is a subsequence of v1."""
    it = iter(v1)
    return all(c in it for c in v2) 

So, the following line returns False.

is_subseq(v2, v1)

Reliable way for a Bash script to get the full path to itself

Use:

SCRIPT_PATH=$(dirname `which $0`)

which prints to standard output the full path of the executable that would have been executed when the passed argument had been entered at the shell prompt (which is what $0 contains)

dirname strips the non-directory suffix from a file name.

Hence you end up with the full path of the script, no matter if the path was specified or not.

Printing PDFs from Windows Command Line

I had the similar problem with printing multiple PDF files in a row and found only workaround by using 2Printer software. Command line example to print PDF files:

2Printer.exe -s "C:\In\*.PDF" -prn "HP LasetJet 1100"

It is free for non-commercial use at http://doc2prn.com/

Padding or margin value in pixels as integer using jQuery

Don't use string.replace("px", ""));

Use parseInt or parseFloat!

Read Excel sheet in Powershell

Sorry I know this is an old one but still felt like helping out ^_^

Maybe it's the way I read this but assuming the excel sheet 1 is called "London" and has this information; B5="Marleybone" B6="Paddington" B7="Victoria" B8="Hammersmith". And the excel sheet 2 is called "Nottingham" and has this information; C5="Alverton" C6="Annesley" C7="Arnold" C8="Askham". Then I think this code below would work. ^_^

$xlCellTypeLastCell = 11 
$startRow = 5

$excel = new-object -com excel.application
$wb = $excel.workbooks.open("C:\users\administrator\my_test.xls")

for ($i = 1; $i -le $wb.sheets.count; $i++)
    {
        $sh = $wb.Sheets.Item($i)
        $endRow = $sh.UsedRange.SpecialCells($xlCellTypeLastCell).Row
        $col = $col + $i - 1
        $city = $wb.Sheets.Item($i).name
        $rangeAddress = $sh.Cells.Item($startRow, $col).Address() + ":" + $sh.Cells.Item($endRow, $col).Address()
        $sh.Range($rangeAddress).Value2 | foreach{
            New-Object PSObject -Property @{City = $city; Area=$_}
        }
    }

$excel.Workbooks.Close()

This should be the output (without the commas):

City, Area
---- ----
London, Marleybone
London, Paddington
London, Victoria
London, Hammersmith
Nottingham, Alverton
Nottingham, Annesley
Nottingham, Arnold
Nottingham, Askham

How to use the addr2line command in Linux?

You need to specify an offset to addr2line, not a virtual address (VA). Presumably if you had address space randomization turned off, you could use a full VA, but in most modern OSes, address spaces are randomized for a new process.

Given the VA 0x4005BDC by valgrind, find the base address of your process or library in memory. Do this by examining the /proc/<PID>/maps file while your program is running. The line of interest is the text segment of your process, which is identifiable by the permissions r-xp and the name of your program or library.

Let's say that the base VA is 0x0x4005000. Then you would find the difference between the valgrind supplied VA and the base VA: 0xbdc. Then, supply that to add2line:

addr2line -e a.out -j .text 0xbdc

And see if that gets you your line number.

Jquery how to find an Object by attribute in an Array

No need for jQuery.

JavaScript arrays have a find method, so you can achieve that in one line:

array.find((o) => { return o[propertyName] === propertyValue }

Example


const purposeObjects = [
    {purpose: "daily"},
    {purpose: "weekly"},
    {purpose: "monthly"}
];

purposeObjects.find((o) => { return o["purpose"] === "weekly" }

// output -> {purpose: "weekly"}

If you need IE compatibility, import this polyfill in your code.

How to clear Facebook Sharer cache?

This answer is intended for developers.

Clearing the cache means that new shares of this webpage will show the new content which is provided in the OG tags. But only if the URL that you are working on has less than 50 interactions (likes + shares). It will also not affect old links to this webpage which have already been posted on Facebook. Only when sharing the URL on Facebook again will the way that Facebook shows the link be updated.

catandmouse's answer is correct but you can also make Facebook clear the OG (OpenGraph) cache by sending a post request to graph.facebook.com (works for both http and https as of the writing of this answer). You do not need an access token.

A post request to graph.facebook.com may look as follows:

POST / HTTP/1.1
Content-Type: application/x-www-form-urlencoded
Host: graph.facebook.com
Content-Length: 63
Accept-Encoding: gzip
User-Agent: Mojolicious (Perl)

id=<url_encoded_url>&scrape=true

In Perl, you can use the following code where the library Mojo::UserAgent is used to send and receive HTTP requests:

sub _clear_og_cache_on_facebook {
    my $fburl     = "http://graph.facebook.com";
    my $ua        = Mojo::UserAgent->new;
    my $clearurl  = <the url you want Facebook to forget>;
    my $post_body = {id => $clearurl, scrape => 'true'};
    my $res       = $ua->post($fburl => form => $post_body)->res;
    my $code      = $res->code;
    unless ($code eq '200') {
        Log->warn("Clearing cached OG data for $clearurl failed with code $code.");
        }
    }
}

Sending this post request through the terminal can be done with the following command:

curl -F id="<URL>" -F scrape=true graph.facebook.com

Curl : connection refused

Try curl -v http://localhost:8080/ instead of 127.0.0.1

How do I automatically set the $DISPLAY variable for my current session?

I'm guessing here, based on issues I've had in the past which I did solve:

  • you're connecting to a vnc server on machine B, displaying it using a VNC client on machine A
  • you're launching a console (xterm or equivalent) on machine B and using that to connect to machine C
  • you want to launch an X-based application on machine C, having it display to the VNC server on machine B, so you can see it on machine A.

I ended up with two solutions. My original solution was based on using rsh. Since then, most of our servers have had ssh installed, which has made this easier.

Using rsh, I put together a table of machines vs OS vs custom options which would guide this process in perl. Bourne shell wasn't sufficient, and we don't have bash on Sun or HP machines (and didn't have bash on AIX at the time - AIX 5L wasn't out yet). Korn shell wasn't much of an option, either, since most of our Linux boxes don't have pdksh installed. But, if you don't face these limitations, you can implement the idea in ksh or bash, I think.

Anyway, I would basically run 'rsh $machine -l $user "$cmd"' where $machine, of course, was the machine I was logging in to, $user, similarly obvious (though when I was going in as "root" this had some variance as we have multiple roots on some machines for reasons I don't fully understand), and $cmd was basically "DISPLAY=$DISPLAY xterm", though if I were launching konsole, for example, $cmd would be "konsole --display=$DISPLAY". Since $DISPLAY was being evaluated locally (where it's set properly), and not being passed literally across rsh, the display would always be set correctly.

I also had to make sure that no one did anything silly like reset DISPLAY if it was already set.

Now, I just use ssh, make sure that X11Forwarding is set to yes on the server (sshd_config), and then I can just ssh to the machine, let X commands go across the wire encrypted, and it'll always go back to the right place.

How can I check for Python version in a program that uses new language features?

I think the best way is to test for functionality rather than versions. In some cases, this is trivial, not so in others.

eg:

try :
    # Do stuff
except : # Features weren't found.
    # Do stuff for older versions.

As long as you're specific in enough in using the try/except blocks, you can cover most of your bases.

Javascript counting number of objects in object

The easiest way to do this, with excellent performance and compatibility with both old and new browsers, is to include either Lo-Dash or Underscore in your page.

Then you can use either _.size(object) or _.keys(object).length

For your obj.Data, you could test this with:

console.log( _.size(obj.Data) );

or:

console.log( _.keys(obj.Data).length );

Lo-Dash and Underscore are both excellent libraries; you would find either one very useful in your code. (They are rather similar to each other; Lo-Dash is a newer version with some advantanges.)

Alternatively, you could include this function in your code, which simply loops through the object's properties and counts them:

function ObjectLength( object ) {
    var length = 0;
    for( var key in object ) {
        if( object.hasOwnProperty(key) ) {
            ++length;
        }
    }
    return length;
};

You can test this with:

console.log( ObjectLength(obj.Data) );

That code is not as fast as it could be in modern browsers, though. For a version that's much faster in modern browsers and still works in old ones, you can use:

function ObjectLength_Modern( object ) {
    return Object.keys(object).length;
}

function ObjectLength_Legacy( object ) {
    var length = 0;
    for( var key in object ) {
        if( object.hasOwnProperty(key) ) {
            ++length;
        }
    }
    return length;
}

var ObjectLength =
    Object.keys ? ObjectLength_Modern : ObjectLength_Legacy;

and as before, test it with:

console.log( ObjectLength(obj.Data) );

This code uses Object.keys(object).length in modern browsers and falls back to counting in a loop for old browsers.

But if you're going to all this work, I would recommend using Lo-Dash or Underscore instead and get all the benefits those libraries offer.

I set up a jsPerf that compares the speed of these various approaches. Please run it in any browsers you have handy to add to the tests.

Thanks to Barmar for suggesting Object.keys for newer browsers in his answer.

Comparing Arrays of Objects in JavaScript

As serialization doesn't work generally (only when the order of properties matches: JSON.stringify({a:1,b:2}) !== JSON.stringify({b:2,a:1})) you have to check the count of properties and compare each property as well:

_x000D_
_x000D_
const objectsEqual = (o1, o2) =>_x000D_
    Object.keys(o1).length === Object.keys(o2).length _x000D_
        && Object.keys(o1).every(p => o1[p] === o2[p]);_x000D_
_x000D_
const obj1 = { name: 'John', age: 33};_x000D_
const obj2 = { age: 33, name: 'John' };_x000D_
const obj3 = { name: 'John', age: 45 };_x000D_
        _x000D_
console.log(objectsEqual(obj1, obj2)); // true_x000D_
console.log(objectsEqual(obj1, obj3)); // false
_x000D_
_x000D_
_x000D_

If you need a deep comparison, you can call the function recursively:

_x000D_
_x000D_
const obj1 = { name: 'John', age: 33, info: { married: true, hobbies: ['sport', 'art'] } };_x000D_
const obj2 = { age: 33, name: 'John', info: { hobbies: ['sport', 'art'], married: true } };_x000D_
const obj3 = { name: 'John', age: 33 };_x000D_
_x000D_
const objectsEqual = (o1, o2) => _x000D_
    typeof o1 === 'object' && Object.keys(o1).length > 0 _x000D_
        ? Object.keys(o1).length === Object.keys(o2).length _x000D_
            && Object.keys(o1).every(p => objectsEqual(o1[p], o2[p]))_x000D_
        : o1 === o2;_x000D_
        _x000D_
console.log(objectsEqual(obj1, obj2)); // true_x000D_
console.log(objectsEqual(obj1, obj3)); // false
_x000D_
_x000D_
_x000D_

Then it's easy to use this function to compare objects in arrays:

const arr1 = [obj1, obj1];
const arr2 = [obj1, obj2];
const arr3 = [obj1, obj3];

const arraysEqual = (a1, a2) => 
   a1.length === a2.length && a1.every((o, idx) => objectsEqual(o, a2[idx]));

console.log(arraysEqual(arr1, arr2)); // true
console.log(arraysEqual(arr1, arr3)); // false

Why does the JFrame setSize() method not set the size correctly?

JFrame SetSize() contains the the Area + Border.

I think you have to set the size of ContentPane of that

jFrame.getContentPane().setSize(800,400);

So I would advise you to use JPanel embedded in a JFrame and you draw on that JPanel. This would minimize your problem.

JFrame jf = new JFrame();
JPanel jp = new JPanel();
jp.setPreferredSize(new Dimension(400,800));// changed it to preferredSize, Thanks!
jf.getContentPane().add( jp );// adding to content pane will work here. Please read the comment bellow.
jf.pack();

I am reading this from Javadoc

The JFrame class is slightly incompatible with Frame. Like all other JFC/Swing top-level containers, a JFrame contains a JRootPane as its only child. The content pane provided by the root pane should, as a rule, contain all the non-menu components displayed by the JFrame. This is different from the AWT Frame case. For example, to add a child to an AWT frame you'd write:

frame.add(child);

However using JFrame you need to add the child to the JFrame's content pane instead:

frame.getContentPane().add(child);

Could not open a connection to your authentication agent

In Windows 10, using the Command Prompt terminal, the following works for me:

ssh-agent cmd 
ssh-add

You should then be asked for a passphrase after this:

Enter passphrase for /c/Users/username/.ssh/id_rsa:

How to create my json string by using C#?

To convert any object or object list into JSON, we have to use the function JsonConvert.SerializeObject.

The below code demonstrates the use of JSON in an ASP.NET environment:

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using Newtonsoft.Json;
using System.Collections.Generic;

namespace JSONFromCS
{
    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e1)
        {
            List<Employee> eList = new List<Employee>();
            Employee e = new Employee();
            e.Name = "Minal";
            e.Age = 24;

            eList.Add(e);

            e = new Employee();
            e.Name = "Santosh";
            e.Age = 24;

            eList.Add(e);

            string ans = JsonConvert.SerializeObject(eList, Formatting.Indented);

            string script = "var employeeList = {\"Employee\": " + ans+"};";
            script += "for(i = 0;i<employeeList.Employee.length;i++)";
            script += "{";
            script += "alert ('Name : ='+employeeList.Employee[i].Name+' 
            Age : = '+employeeList.Employee[i].Age);";
            script += "}";

            ClientScriptManager cs = Page.ClientScript;
            cs.RegisterStartupScript(Page.GetType(), "JSON", script, true);
        }
    }
    public class Employee
    {
        public string Name;
        public int Age;
    }
}  

After running this program, you will get two alerts

In the above example, we have created a list of Employee object and passed it to function "JsonConvert.SerializeObject". This function (JSON library) will convert the object list into JSON format. The actual format of JSON can be viewed in the below code snippet:

{ "Maths" : [ {"Name"     : "Minal",        // First element
                             "Marks"     : 84,
                             "age"       : 23 },
                             {
                             "Name"      : "Santosh",    // Second element
                             "Marks"     : 91,
                             "age"       : 24 }
                           ],                       
              "Science" :  [ 
                             {
                             "Name"      : "Sahoo",     // First Element
                             "Marks"     : 74,
                             "age"       : 27 }, 
                             {                           
                             "Name"      : "Santosh",    // Second Element
                             "Marks"     : 78,
                             "age"       : 41 }
                           ] 
            } 

Syntax:

  • {} - acts as 'containers'

  • [] - holds arrays

  • : - Names and values are separated by a colon

  • , - Array elements are separated by commas

This code is meant for intermediate programmers, who want to use C# 2.0 to create JSON and use in ASPX pages.

You can create JSON from JavaScript end, but what would you do to convert the list of object into equivalent JSON string from C#. That's why I have written this article.

In C# 3.5, there is an inbuilt class used to create JSON named JavaScriptSerializer.

The following code demonstrates how to use that class to convert into JSON in C#3.5.

JavaScriptSerializer serializer = new JavaScriptSerializer()
return serializer.Serialize(YOURLIST);   

So, try to create a List of arrays with Questions and then serialize this list into JSON

SQL Server : error converting data type varchar to numeric

I think the problem is not in sub-query but in WHERE clause of outer query. When you use

WHERE account_code between 503100 and 503105

SQL server will try to convert every value in your Account_code field to integer to test it in provided condition. Obviously it will fail to do so if there will be non-integer characters in some rows.

POI setting Cell Background to a Custom Color

Don't forget to call this.

style.setFillPattern(CellStyle.Align_Fill);

Parameter may differ according to your need. Maybe CellStyle.FINE_DOTS or so.

Add content to a new open window

in parent.html:

<script type="text/javascript">
    $(document).ready(function () {
        var output = "data";
        var OpenWindow = window.open("child.html", "mywin", '');
        OpenWindow.dataFromParent = output; // dataFromParent is a variable in child.html
        OpenWindow.init();
    });
</script>

in child.html:

<script type="text/javascript">
    var dataFromParent;    
    function init() {
        document.write(dataFromParent);
    }
</script>

SQLSTATE[HY000] [1045] Access denied for user 'username'@'localhost' using CakePHP

I want to add to the answers posted on above that none of the solutions proposed here worked for me. My WAMP, is working on port 3308 instead of 3306 which is what it is installed by default. I found out that when working in a local environment, if you are using mysqladmin in your computer (for testing environment), and if you are working with port other than 3306, you must define your variable DB_SERVER with the value localhost:NumberOfThePort, so it will look like the following: define("DB_SERVER", "localhost:3308"). You can obtain this value by right-clicking on the WAMP icon in your taskbar (on the hidden icons section) and select Tools. You will see the section: "Port used by MySQL: NumberOfThePort"

This will fix your connection to your database.

This was the error I got: Error: SQLSTATE[HY1045] Access denied for user 'username'@'localhost' on line X.

I hope this helps you out.

:)

Can't access Tomcat using IP address

Very strange because the firewall caused the issue.

What is the Maximum Size that an Array can hold?

Since Length is an int I'd say Int.MaxValue

What is the best way to check for Internet connectivity using .NET?

Instead of checking, just perform the action (web request, mail, ftp, etc.) and be prepared for the request to fail, which you have to do anyway, even if your check was successful.

Consider the following:

1 - check, and it is OK
2 - start to perform action 
3 - network goes down
4 - action fails
5 - lot of good your check did

If the network is down your action will fail just as rapidly as a ping, etc.

1 - start to perform action
2 - if the net is down(or goes down) the action will fail

How to delete the top 1000 rows from a table using Sql Server 2008?

The code you tried is in fact two statements. A DELETE followed by a SELECT.

You don't define TOP as ordered by what.

For a specific ordering criteria deleting from a CTE or similar table expression is the most efficient way.

;WITH CTE AS
(
SELECT TOP 1000 *
FROM [mytab]
ORDER BY a1
)
DELETE FROM CTE

How can I run a program from a batch file without leaving the console open after the program starts?

You should try this. It starts the program with no window. It actually flashes up for a second but goes away fairly quickly.

start "name" /B myprogram.exe param1

How do I concatenate two strings in C?

In C, you don't really have strings, as a generic first-class object. You have to manage them as arrays of characters, which mean that you have to determine how you would like to manage your arrays. One way is to normal variables, e.g. placed on the stack. Another way is to allocate them dynamically using malloc.

Once you have that sorted, you can copy the content of one array to another, to concatenate two strings using strcpy or strcat.

Having said that, C do have the concept of "string literals", which are strings known at compile time. When used, they will be a character array placed in read-only memory. It is, however, possible to concatenate two string literals by writing them next to each other, as in "foo" "bar", which will create the string literal "foobar".

IIS: Idle Timeout vs Recycle

IIS now has

Idle Time-out Action : Suspend setting

Suspending is just freezes the process and it is much more efficient than the destroying the process.

Copy or rsync command

if you are using cp doesn't save existing files when copying folders of the same name. Lets say you have this folders:

/myFolder
  someTextFile.txt

/someOtherFolder
  /myFolder
    wellHelloThere.txt

Then you copy one over the other:

cp /someOtherFolder/myFolder /myFolder

result:

/myFolder
  wellHelloThere.txt

This is at least what happens on macOS and I wanted to preserve the diff files so I used rsync.

Manifest Merger failed with multiple errors in Android Studio

This is because you are using the new Material library with the legacy Support Library.

You have to migrate android.support to androidx in order to use com.google.android.material.

If you are using android studio v 3.2 or above, simply

go to refactor ---> MIGRATE TO ANDROID X.

Do make a backup of your project.

What does 'x packages are looking for funding' mean when running `npm install`?

npm install --silent

Seems to suppress the funding issue.

Compile c++14-code with g++

Follow the instructions at https://gist.github.com/application2000/73fd6f4bf1be6600a2cf9f56315a2d91 to set up the gcc version you need - gcc 5 or gcc 6 - on Ubuntu 14.04. The instructions include configuring update-alternatives to allow you to switch between versions as you need to.

How do I get the currently-logged username from a Windows service in .NET?

Modified code of Tapas's answer:

Dim searcher As New ManagementObjectSearcher("SELECT UserName FROM Win32_ComputerSystem")
Dim collection As ManagementObjectCollection = searcher.[Get]()
Dim username As String
For Each oReturn As ManagementObject In collection
    username = oReturn("UserName")
Next

Changing file extension in Python

import os
thisFile = "mysequence.fasta"
base = os.path.splitext(thisFile)[0]
os.rename(thisFile, base + ".aln")

Where thisFile = the absolute path of the file you are changing

The server encountered an internal error or misconfiguration and was unable to complete your request

Check your servers error log, typically /var/log/apache2/error.log.

Can not deserialize instance of java.lang.String out of START_OBJECT token

If you do not want to define a separate class for nested json , Defining nested json object as JsonNode should work ,for example :

{"id":2,"socket":"0c317829-69bf-43d6-b598-7c0c550635bb","type":"getDashboard","data":{"workstationUuid":"ddec1caa-a97f-4922-833f-632da07ffc11"},"reply":true}

@JsonProperty("data")
    private JsonNode data;

How do I write a compareTo method which compares objects?

The compareTo method is described as follows:

Compares this object with the specified object for order. Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object.

Let's say we would like to compare Jedis by their age:

class Jedi implements Comparable<Jedi> {

    private final String name;
    private final int age;
        //...
}

Then if our Jedi is older than the provided one, you must return a positive, if they are the same age, you return 0, and if our Jedi is younger you return a negative.

public int compareTo(Jedi jedi){
    return this.age > jedi.age ? 1 : this.age < jedi.age ? -1 : 0;
}

By implementing the compareTo method (coming from the Comparable interface) your are defining what is called a natural order. All sorting methods in JDK will use this ordering by default.

There are ocassions in which you may want to base your comparision in other objects, and not on a primitive type. For instance, copare Jedis based on their names. In this case, if the objects being compared already implement Comparable then you can do the comparison using its compareTo method.

public int compareTo(Jedi jedi){
    return this.name.compareTo(jedi.getName());
}

It would be simpler in this case.

Now, if you inted to use both name and age as the comparison criteria then you have to decide your oder of comparison, what has precedence. For instance, if two Jedis are named the same, then you can use their age to decide which goes first and which goes second.

public int compareTo(Jedi jedi){
    int result = this.name.compareTo(jedi.getName());
    if(result == 0){
        result = this.age > jedi.age ? 1 : this.age < jedi.age ? -1 : 0;
    }
    return result;
}

If you had an array of Jedis

Jedi[] jediAcademy = {new Jedi("Obiwan",80), new Jedi("Anakin", 30), ..}

All you have to do is to ask to the class java.util.Arrays to use its sort method.

Arrays.sort(jediAcademy);

This Arrays.sort method will use your compareTo method to sort the objects one by one.

Ignoring NaNs with str.contains

In addition to the above answers, I would say for columns having no single word name, you may use:-

df[df['Product ID'].str.contains("foo") == True]

Hope this helps.

PHP - iterate on string characters

// Unicode Codepoint Escape Syntax in PHP 7.0
$str = "cat!\u{1F431}";

// IIFE (Immediately Invoked Function Expression) in PHP 7.0
$gen = (function(string $str) {
    for ($i = 0, $len = mb_strlen($str); $i < $len; ++$i) {
        yield mb_substr($str, $i, 1);
    }
})($str);

var_dump(
    true === $gen instanceof Traversable,
    // PHP 7.1
    true === is_iterable($gen)
);

foreach ($gen as $char) {
    echo $char, PHP_EOL;
}

How can I make all images of different height and width the same via CSS?

Go to your CSS file and resize all your images as follows

img {
  width:  100px;
  height: 100px;
}

Why is 22 the default port number for SFTP?

From Wikipedia:

Applications implementing common services often use specifically reserved, well-known port numbers for receiving service requests from client hosts. This process is known as listening and involves the receipt of a request on the well-known port and reestablishing one-to-one server-client communications on another private port, so that other clients may also contact the well-known service port. The well-known ports are defined by convention overseen by the Internet Assigned Numbers Authority (IANA).

Source

So as others mentioned, it's a convention.

How to capture a JFrame's close button click event?

This is what I put as a menu option where I made a button on a JFrame to display another JFrame. I wanted only the new frame to be visible, and not to destroy the one behind it. I initially hid the first JFrame, while the new one became visible. Upon closing of the new JFrame, I disposed of it followed by an action of making the old one visible again.

Note: The following code expands off of Ravinda's answer and ng is a JButton:

ng.addActionListener((ActionEvent e) -> {
    setVisible(false);
    JFrame j = new JFrame("NAME");
    j.setVisible(true);
    j.addWindowListener(new java.awt.event.WindowAdapter() {
        @Override
        public void windowClosing(java.awt.event.WindowEvent windowEvent) {
            setVisible(true);
        }
    });
});

Default value to a parameter while passing by reference in C++

It has been said in one of the direct comments to your answer already, but just to state it officially. What you want to use is an overload:

virtual const ULONG Write(ULONG &State, bool sequence);
inline const ULONG Write()
{
  ULONG state;
  bool sequence = true;
  Write (state, sequence);
}

Using function overloads also have additional benefits. Firstly you can default any argument you wish:

class A {}; 
class B {}; 
class C {};

void foo (A const &, B const &, C const &);
void foo (B const &, C const &); // A defaulted
void foo (A const &, C const &); // B defaulted
void foo (C const &); // A & B defaulted etc...

It is also possible to redefine default arguments to virtual functions in derived class, which overloading avoids:

class Base {
public:
  virtual void f1 (int i = 0);  // default '0'

  virtual void f2 (int);
  inline void f2 () {
    f2(0);                      // equivalent to default of '0'
  }
};

class Derived : public Base{
public:
  virtual void f1 (int i = 10);  // default '10'

  using Base::f2;
  virtual void f2 (int);
};

void bar ()
{
  Derived d;
  Base & b (d);
  d.f1 ();   // '10' used
  b.f1 ();   // '0' used

  d.f2 ();   // f1(int) called with '0' 
  b.f2 ();   // f1(int) called with '0
}

There is only one situation where a default really needs to be used, and that is on a constructor. It is not possible to call one constructor from another, and so this technique does not work in that case.

No module named serial

  1. Firstly uninstall pyserial using the command pip uninstall pyserial
  2. Then go to https://www.lfd.uci.edu/~gohlke/pythonlibs/
  3. download the suitable pyserial version and then go to the directory where the file is downloaded and open cmd there
  4. then type pip install "filename"(without quotes)

MySQL match() against() - order by relevance and column?

I have never done so, but it seems like

MATCH (head, head, body) AGAINST ('some words' IN BOOLEAN MODE)

Should give a double weight to matches found in the head.


Just read this comment on the docs page, Thought it might be of value to you:

Posted by Patrick O'Lone on December 9 2002 6:51am

It should be noted in the documentation that IN BOOLEAN MODE will almost always return a relevance of 1.0. In order to get a relevance that is meaningful, you'll need to:

SELECT MATCH('Content') AGAINST ('keyword1 keyword2') as Relevance 
FROM table 
WHERE MATCH ('Content') AGAINST('+keyword1+keyword2' IN BOOLEAN MODE) 
HAVING Relevance > 0.2 
ORDER BY Relevance DESC 

Notice that you are doing a regular relevance query to obtain relevance factors combined with a WHERE clause that uses BOOLEAN MODE. The BOOLEAN MODE gives you the subset that fulfills the requirements of the BOOLEAN search, the relevance query fulfills the relevance factor, and the HAVING clause (in this case) ensures that the document is relevant to the search (i.e. documents that score less than 0.2 are considered irrelevant). This also allows you to order by relevance.

This may or may not be a bug in the way that IN BOOLEAN MODE operates, although the comments I've read on the mailing list suggest that IN BOOLEAN MODE's relevance ranking is not very complicated, thus lending itself poorly for actually providing relevant documents. BTW - I didn't notice a performance loss for doing this, since it appears MySQL only performs the FULLTEXT search once, even though the two MATCH clauses are different. Use EXPLAIN to prove this.

So it would seem you may not need to worry about calling the fulltext search twice, though you still should "use EXPLAIN to prove this"

Create hive table using "as select" or "like" and also specify delimiter

Let's say we have an external table called employee

hive> SHOW CREATE TABLE employee;
OK
CREATE EXTERNAL TABLE employee(
  id string,
  fname string,
  lname string, 
  salary double)
ROW FORMAT SERDE
  'org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe'
WITH SERDEPROPERTIES (
  'colelction.delim'=':',
  'field.delim'=',',
  'line.delim'='\n',
  'serialization.format'=',')
STORED AS INPUTFORMAT
  'org.apache.hadoop.mapred.TextInputFormat'
OUTPUTFORMAT
  'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat'
LOCATION
  'maprfs:/user/hadoop/data/employee'
TBLPROPERTIES (
  'COLUMN_STATS_ACCURATE'='false',
  'numFiles'='0',
  'numRows'='-1',
  'rawDataSize'='-1',
  'totalSize'='0',
  'transient_lastDdlTime'='1487884795')
  1. To create a person table like employee

    CREATE TABLE person LIKE employee;

  2. To create a person external table like employee

    CREATE TABLE person LIKE employee LOCATION 'maprfs:/user/hadoop/data/person';

  3. then use DESC person; to see the newly created table schema.

Alter MySQL table to add comments on columns

try:

 ALTER TABLE `user` CHANGE `id` `id` INT( 11 ) COMMENT 'id of user'  

SQL SERVER DATETIME FORMAT

Compatibility Supports Says that Under compatibility level 110, the default style for CAST and CONVERT operations on time and datetime2 data types is always 121. If your query relies on the old behavior, use a compatibility level less than 110, or explicitly specify the 0 style in the affected query.

That means by default datetime2 is CAST as varchar to 121 format. For ex; col1 and col2 formats (below) are same (other than the 0s at the end)

SELECT CONVERT(varchar, GETDATE(), 121) col1,
       CAST(convert(datetime2,GETDATE()) as varchar) col2,
       CAST(GETDATE() as varchar) col3

SQL FIDDLE DEMO

--Results
COL1                    | COL2                          | COL3
2013-02-08 09:53:56.223 | 2013-02-08 09:53:56.2230000   | Feb 8 2013 9:53AM

FYI, if you use CONVERT instead of CAST you can use a third parameter to specify certain formats as listed here on MSDN

Node.js console.log() not logging anything

This can be confusing for anyone using nodejs for the first time. It is actually possible to pipe your node console output to the browser console. Take a look at connect-browser-logger on github

UPDATE: As pointed out by Yan, connect-browser-logger appears to be defunct. I would recommend NodeMonkey as detailed here : Output to Chrome console from Node.js

Using multiple IF statements in a batch file

You can structurize your batch file by using goto

IF EXIST somefile.txt goto somefileexists
goto exit

:somefileexists
IF EXIST someotherfile.txt SET var=...

:exit

Python Pylab scatter plot error bars (the error on each point is unique)

>>> import matplotlib.pyplot as plt
>>> a = [1,3,5,7]
>>> b = [11,-2,4,19]
>>> plt.pyplot.scatter(a,b)
>>> plt.scatter(a,b)
<matplotlib.collections.PathCollection object at 0x00000000057E2CF8>
>>> plt.show()
>>> c = [1,3,2,1]
>>> plt.errorbar(a,b,yerr=c, linestyle="None")
<Container object of 3 artists>
>>> plt.show()

where a is your x data b is your y data c is your y error if any

note that c is the error in each direction already

How to pass a list from Python, by Jinja2 to JavaScript

I can suggest you a javascript oriented approach which makes it easy to work with javascript files in your project.

Create a javascript section in your jinja template file and place all variables you want to use in your javascript files in a window object:

Start.html

...
{% block scripts %}
<script type="text/javascript">
window.appConfig = {
    debug: {% if env == 'development' %}true{% else %}false{% endif %},
    facebook_app_id: {{ facebook_app_id }},
    accountkit_api_version: '{{ accountkit_api_version }}',
    csrf_token: '{{ csrf_token }}'
}
</script>
<script type="text/javascript" src="{{ url_for('static', filename='app.js') }}"></script>
{% endblock %}

Jinja will replace values and our appConfig object will be reachable from our other script files:

App.js

var AccountKit_OnInteractive = function(){
    AccountKit.init({
        appId: appConfig.facebook_app_id,
        debug: appConfig.debug,
        state: appConfig.csrf_token,
        version: appConfig.accountkit_api_version
    })
}

I have seperated javascript code from html documents with this way which is easier to manage and seo friendly.

onchange equivalent in angular2

You can use:

<input (input)="saverange()>

What does API level mean?

An API is ready-made source code library.

In Java for example APIs are a set of related classes and interfaces that come in packages. This picture illustrates the libraries included in the Java Standard Edition API. Packages are denoted by their color.

This pictures illustrates the libraries included in the Java Standard Edition API

Run git pull over all subdirectories

Run the following from the parent directory, plugins in this case:

find . -type d -depth 1 -exec git --git-dir={}/.git --work-tree=$PWD/{} pull origin master \;

To clarify:

  • find . searches the current directory
  • -type d to find directories, not files
  • -depth 1 for a maximum depth of one sub-directory
  • -exec {} \; runs a custom command for every find
  • git --git-dir={}/.git --work-tree=$PWD/{} pull git pulls the individual directories

To play around with find, I recommend using echo after -exec to preview, e.g.:

find . -type d -depth 1 -exec echo git --git-dir={}/.git --work-tree=$PWD/{} status \;

Note: if the -depth 1 option is not available, try -mindepth 1 -maxdepth 1.

How do I use the new computeIfAbsent function?

multi-map

This is really helpful if you want to create a multimap without resorting to the Google Guava library for its implementation of MultiMap.

For example, suppose you want to store a list of students who enrolled for a particular subject.

The normal solution for this using JDK library is:

Map<String,List<String>> studentListSubjectWise = new TreeMap<>();
List<String>lis = studentListSubjectWise.get("a");
if(lis == null) {
    lis = new ArrayList<>();
}
lis.add("John");

//continue....

Since it have some boilerplate code, people tend to use Guava Mutltimap.

Using Map.computeIfAbsent, we can write in a single line without guava Multimap as follows.

studentListSubjectWise.computeIfAbsent("a", (x -> new ArrayList<>())).add("John");

Stuart Marks & Brian Goetz did a good talk about this https://www.youtube.com/watch?v=9uTVXxJjuco

How to log Apache CXF Soap Request and Soap Response using Log4j?

Another easy way is to set the logger like this- ensure that you do it before you load the cxf web service related classes. You can use it in some static blocks.

YourClientConstructor() {

  LogUtils.setLoggerClass(org.apache.cxf.common.logging.Log4jLogger.class);

  URL wsdlURL = YOurURL;//

  //create the service
  YourService = new YourService(wsdlURL, SERVICE_NAME);
  port = yourService.getServicePort(); 

  Client client = ClientProxy.getClient(port);
  client.getInInterceptors().add(new LoggingInInterceptor());
  client.getOutInterceptors().add(new LoggingOutInterceptor());
}

Then the inbound and outbound messages will be printed to Log4j file instead of the console. Make sure your log4j is configured properly

Copy multiple files in Python

Here is another example of a recursive copy function that lets you copy the contents of the directory (including sub-directories) one file at a time, which I used to solve this problem.

import os
import shutil

def recursive_copy(src, dest):
    """
    Copy each file from src dir to dest dir, including sub-directories.
    """
    for item in os.listdir(src):
        file_path = os.path.join(src, item)

        # if item is a file, copy it
        if os.path.isfile(file_path):
            shutil.copy(file_path, dest)

        # else if item is a folder, recurse 
        elif os.path.isdir(file_path):
            new_dest = os.path.join(dest, item)
            os.mkdir(new_dest)
            recursive_copy(file_path, new_dest)

EDIT: If you can, definitely just use shutil.copytree(src, dest). This requires that that destination folder does not already exist though. If you need to copy files into an existing folder, the above method works well!

How to detect reliably Mac OS X, iOS, Linux, Windows in C preprocessor?

As Jake points out, TARGET_IPHONE_SIMULATOR is a subset of TARGET_OS_IPHONE.

Also, TARGET_OS_IPHONE is a subset of TARGET_OS_MAC.

So a better approach might be:

#ifdef _WIN64
   //define something for Windows (64-bit)
#elif _WIN32
   //define something for Windows (32-bit)
#elif __APPLE__
    #include "TargetConditionals.h"
    #if TARGET_OS_IPHONE && TARGET_IPHONE_SIMULATOR
        // define something for simulator   
    #elif TARGET_OS_IPHONE
        // define something for iphone  
    #else
        #define TARGET_OS_OSX 1
        // define something for OSX
    #endif
#elif __linux
    // linux
#elif __unix // all unices not caught above
    // Unix
#elif __posix
    // POSIX
#endif

Solutions for INSERT OR UPDATE on SQL Server

don't forget about transactions. Performance is good, but simple (IF EXISTS..) approach is very dangerous.
When multiple threads will try to perform Insert-or-update you can easily get primary key violation.

Solutions provided by @Beau Crawford & @Esteban show general idea but error-prone.

To avoid deadlocks and PK violations you can use something like this:

begin tran
if exists (select * from table with (updlock,serializable) where key = @key)
begin
   update table set ...
   where key = @key
end
else
begin
   insert into table (key, ...)
   values (@key, ...)
end
commit tran

or

begin tran
   update table with (serializable) set ...
   where key = @key

   if @@rowcount = 0
   begin
      insert into table (key, ...) values (@key,..)
   end
commit tran

XSL xsl:template match="/"

The value of the match attribute of the <xsl:template> instruction must be a match pattern.

Match patterns form a subset of the set of all possible XPath expressions. The first, natural, limitation is that a match pattern must select a set of nodes. There are also other limitations. In particular, reverse axes are not allowed in the location steps (but can be specified within the predicates). Also, no variable or parameter references are allowed in XSLT 1.0, but using these is legal in XSLT 2.x.

/ in XPath denotes the root or document node. In XPath 2.0 (and hence XSLT 2.x) this can also be written as document-node().

A match pattern can contain the // abbreviation.

Examples of match patterns:

<xsl:template match="table">

can be applied on any element named table.

<xsl:template match="x/y">

can be applied on any element named y whose parent is an element named x.

<xsl:template match="*">

can be applied to any element.

<xsl:template match="/*">

can be applied only to the top element of an XML document.

<xsl:template match="@*">

can be applied to any attribute.

<xsl:template match="text()">

can be applied to any text node.

<xsl:template match="comment()">

can be applied to any comment node.

<xsl:template match="processing-instruction()">

can be applied to any processing instruction node.

<xsl:template match="node()">

can be applied to any node: element, text, comment or processing instructon.

How can I create a dynamic button click event on a dynamic button?

The easier one for newbies:

Button button = new Button();
button.Click += new EventHandler(button_Click);

protected void button_Click (object sender, EventArgs e)
{
    Button button = sender as Button;
    // identify which button was clicked and perform necessary actions
}

Send Message in C#

Building on Mark Byers's answer.

The 3rd project could be a WCF project, hosted as a Windows Service. If all programs listened to that service, one application could call the service. The service passes the message on to all listening clients and they can perform an action if suitable.

Good WCF videos here - http://msdn.microsoft.com/en-us/netframework/dd728059

How do I get logs from all pods of a Kubernetes replication controller?

In this example, you can replace the <namespace> and <app-name> to get the logs when there are multiple Containers defined in a Pod.

kubectl -n <namespace> logs -f deployment/<app-name> \
    --all-containers=true --since=10m

Checking if a key exists in a JavaScript object?

A fast and easy solution is to convert your object to json then you will be able to do this easy task:

const allowed = {
    '/login' : '',
    '/register': '',
    '/resetpsw': ''
};
console.log('/login' in allowed); //returns true

If you use an array the object key will be converted to integers ex 0,1,2,3 etc. therefore, it will always be false

Java - Convert image to Base64

The line

base64String = Base64.encode(byteArray);

converts the full array (102400 bytes) to Base64, not just the number of bytes you have read. You need to pass it the numbers of bytes.

Vue.js img src concatenate variable and text

For me, it said Module did not found and not worked. Finally, I found this solution and worked.

<img v-bind:src="require('@' + baseUrl + 'path/path' + obj.key +'.png')"/>

Needed to add '@' at the beginning of the local path.

Map and Reduce in .NET

Linq equivalents of Map and Reduce: If you’re lucky enough to have linq then you don’t need to write your own map and reduce functions. C# 3.5 and Linq already has it albeit under different names.

  • Map is Select:

    Enumerable.Range(1, 10).Select(x => x + 2);
    
  • Reduce is Aggregate:

    Enumerable.Range(1, 10).Aggregate(0, (acc, x) => acc + x);
    
  • Filter is Where:

    Enumerable.Range(1, 10).Where(x => x % 2 == 0);
    

https://www.justinshield.com/2011/06/mapreduce-in-c/

convert a JavaScript string variable to decimal/money

I made a little helper function to do this and catch all malformed data

function convertToPounds(str) { 
    var n = Number.parseFloat(str);
    if(!str || isNaN(n) || n < 0) return 0;
    return n.toFixed(2);
}

Demo is here

Python Flask, how to set content type

You can try the following method(python3.6.2):

case one:

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

    headers={ 'content-type':'text/plain' ,'location':'http://www.stackoverflow'}
    response = make_response('<h1>hello world</h1>',301)
    response.headers = headers
    return response

case two:

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

    headers={ 'content-type':'text/plain' ,'location':'http://www.stackoverflow.com'}
    return '<h1>hello world</h1>',301,headers

I am using Flask .And if you want to return json,you can write this:

import json # 
@app.route('/search/<keyword>')
def search(keyword):

    result = Book.search_by_keyword(keyword)
    return json.dumps(result),200,{'content-type':'application/json'}


from flask import jsonify
@app.route('/search/<keyword>')
def search(keyword):

    result = Book.search_by_keyword(keyword)
    return jsonify(result)

Set adb vendor keys

I had the same problem running Ubuntu 18.04. I tried multiple solutions but my device (OnePlus 5T) was always unauthorized.

Solution

  1. Configure udev rules on Ubuntu. To do this, just follow the official documentation: https://developer.android.com/studio/run/device

    The idVendor of my device (OnePlus) is not listed. To get it, just connect your device and use lsusb:

    Bus 003 Device 008: ID 2a70:4ee7

    In this example, 2a70 is the idVendor.

  2. Remove existing adb keys on Ubuntu:

    rm -v ~/.android/adbkey* ~/.android/adbkey ~/.android/adbkey.pub

  3. 'Revoke USB debugging authorizations' on your device configuration (developer options).

  4. Finally, restart the adb server to create a new key:

    sudo adb kill-server sudo adb devices

After that, I got the authorization prompt on my device and I authorized it.

How can I check if a string contains a character in C#?

Use the function String.Contains();

an example call,

abs.Contains("s"); // to look for lower case s

here is more from MSDN.

How to prevent errno 32 broken pipe?

The broken pipe error usually occurs if your request is blocked or takes too long and after request-side timeout, it'll close the connection and then, when the respond-side (server) tries to write to the socket, it will throw a pipe broken error.

phpmyadmin "no data received to import" error, how to fix?

No data was received to import. Either no file name was submitted, or the file size exceeded the maximum size permitted by your PHP configuration. See FAQ 1.16.

These are my upload settings from php.ini
upload_tmp_dir = "D:\xampp\xampp\tmp"       ;//set these for temp file storing

; Maximum allowed size for uploaded files.
; http://php.net/upload-max-filesize
upload_max_filesize = 10M    ;//change it according to max file upload size

I am sure your problem will be short out using this instructions.

 upload_tmp_dir = "D:\xampp\xampp\tmp"

Here you can set any directory that can hold temp file, I have installed in D: drive xampp so I set it "D:\xampp\xampp\tmp".

Fatal error: iostream: No such file or directory in compiling C program using GCC

Neither <iostream> nor <iostream.h> are standard C header files. Your code is meant to be C++, where <iostream> is a valid header. Use g++ (and a .cpp file extension) for C++ code.

Alternatively, this program uses mostly constructs that are available in C anyway. It's easy enough to convert the entire program to compile using a C compiler. Simply remove #include <iostream> and using namespace std;, and replace cout << endl; with putchar('\n');... I advise compiling using C99 (eg. gcc -std=c99)

How to set image width to be 100% and height to be auto in react native?

I've found a solution for width: "100%", height: "auto" if you know the aspectRatio (width / height) of the image.

Here's the code:

import { Image, StyleSheet, View } from 'react-native';

const image = () => (
    <View style={styles.imgContainer}>
        <Image style={styles.image} source={require('assets/images/image.png')} />
    </View>
);

const style = StyleSheet.create({
    imgContainer: {
        flexDirection: 'row'
    },
    image: {
        resizeMode: 'contain',
        flex: 1,
        aspectRatio: 1 // Your aspect ratio
    }
});

This is the most simplest way I could get it to work without using onLayout or Dimension calculations. You can even wrap it in a simple reusable component if needed. Give it a shot if anyone is looking for a simple implementation.

Alternate background colors for list items

If you use the jQuery solution it will work on IE8:

jQuery

$(document).ready(function(){
$('#myList li:nth-child(odd)').addClass('alternate');
});

CSS

.alternate {
background: black;
}

If you use the CSS soloution it won't work on IE8:

li:nth-child(odd) {
    background: black;
}

Combine two columns of text in pandas dataframe

Let us suppose your dataframe is df with columns Year and Quarter.

import pandas as pd
df = pd.DataFrame({'Quarter':'q1 q2 q3 q4'.split(), 'Year':'2000'})

Suppose we want to see the dataframe;

df
>>>  Quarter    Year
   0    q1      2000
   1    q2      2000
   2    q3      2000
   3    q4      2000

Finally, concatenate the Year and the Quarter as follows.

df['Period'] = df['Year'] + ' ' + df['Quarter']

You can now print df to see the resulting dataframe.

df
>>>  Quarter    Year    Period
    0   q1      2000    2000 q1
    1   q2      2000    2000 q2
    2   q3      2000    2000 q3
    3   q4      2000    2000 q4

If you do not want the space between the year and quarter, simply remove it by doing;

df['Period'] = df['Year'] + df['Quarter']

EntityType has no key defined error

Additionally Remember, Don't forget to add public keyword like this

[Key] 
int RoleId { get; set; } //wrong method

you must use Public keyword like this

[Key] 
public int RoleId { get; set; } //correct method

Setting values of input fields with Angular 6

You should use the following:

       <td><input id="priceInput-{{orderLine.id}}" type="number" [(ngModel)]="orderLine.price"></td>

You will need to add the FormsModule to your app.module in the inputs section as follows:

import { FormsModule } from '@angular/forms';

@NgModule({
  declarations: [
    ...
  ],
  imports: [
    BrowserModule,
    FormsModule
  ],
  ..

The use of the brackets around the ngModel are as follows:

  • The [] show that it is taking an input from your TS file. This input should be a public member variable. A one way binding from TS to HTML.

  • The () show that it is taking output from your HTML file to a variable in the TS file. A one way binding from HTML to TS.

  • The [()] are both (e.g. a two way binding)

See here for more information: https://angular.io/guide/template-syntax

I would also suggest replacing id="priceInput-{{orderLine.id}}" with something like this [id]="getElementId(orderLine)" where getElementId(orderLine) returns the element Id in the TS file and can be used anywere you need to reference the element (to avoid simple bugs like calling it priceInput1 in one place and priceInput-1 in another. (if you still need to access the input by it's Id somewhere else)

How do I convert a long to a string in C++?

   #include <sstream>


   ....

    std::stringstream ss;
    ss << a_long_int;  // or any other type
    std::string result=ss.str();   // use .str() to get a string back

What is the difference between .text, .value, and .value2?

Except first answer form Bathsheba, except MSDN information for:

.Value
.Value2
.Text

you could analyse these tables for better understanding of differences between analysed properties.

enter image description here

How can I detect when an Android application is running in the emulator?

I tried several techniques, but settled on a slightly revised version of checking the Build.PRODUCT as below. This seems to vary quite a bit from emulator to emulator, that's why I have the 3 checks I currently have. I guess I could have just checked if product.contains("sdk") but thought the check below was a bit safer.

public static boolean isAndroidEmulator() {
    String model = Build.MODEL;
    Log.d(TAG, "model=" + model);
    String product = Build.PRODUCT;
    Log.d(TAG, "product=" + product);
    boolean isEmulator = false;
    if (product != null) {
        isEmulator = product.equals("sdk") || product.contains("_sdk") || product.contains("sdk_");
    }
    Log.d(TAG, "isEmulator=" + isEmulator);
    return isEmulator;
}

FYI - I found that my Kindle Fire had Build.BRAND = "generic", and some of the emulators didn't have "Android" for the network operator.

How to validate Google reCAPTCHA v3 on server side?

this is solution

index.html

<html>
  <head>
    <title>Google recapcha demo - Codeforgeek</title>
    <script src='https://www.google.com/recaptcha/api.js'></script>
  </head>
  <body>
    <h1>Google reCAPTHA Demo</h1>
    <form id="comment_form" action="form.php" method="post">
      <input type="email" placeholder="Type your email" size="40"><br><br>
      <textarea name="comment" rows="8" cols="39"></textarea><br><br>
      <input type="submit" name="submit" value="Post comment"><br><br>
      <div class="g-recaptcha" data-sitekey="=== Your site key ==="></div>
    </form>
  </body>
</html>

verify.php

<?php
    $email; $comment; $captcha;

    if(isset($_POST['email']))
        $email=$_POST['email'];
    if(isset($_POST['comment']))
        $comment=$_POST['comment'];
    if(isset($_POST['g-recaptcha-response']))
        $captcha=$_POST['g-recaptcha-response'];

    if(!$captcha){
        echo '<h2>Please check the the captcha form.</h2>';
        exit;
    }

    $response = json_decode(file_get_contents("https://www.google.com/recaptcha/api/siteverify?secret=YOUR SECRET KEY&response=".$captcha."&remoteip=".$_SERVER['REMOTE_ADDR']), true);
    if($response['success'] == false)
    {
        echo '<h2>You are spammer ! Get the @$%K out</h2>';
    }
    else
    {
        echo '<h2>Thanks for posting comment.</h2>';
    }
?>

http://codeforgeek.com/2014/12/google-recaptcha-tutorial/

Font awesome is not showing icon

I was trying to add fa 5.0.13 to drupal 8 with scss. The styles are not included by default in the main fa.scss had to add them manually.

@import "libraries/fontawesome/fa-brands";
@import "libraries/fontawesome/fa-light";
@import "libraries/fontawesome/fa-regular";
@import "libraries/fontawesome/fa-solid";

Declare and initialize a Dictionary in Typescript

For using dictionary object in typescript you can use interface as below:

interface Dictionary<T> {
    [Key: string]: T;
}

and, use this for your class property type.

export class SearchParameters {
    SearchFor: Dictionary<string> = {};
}

to use and initialize this class,

getUsers(): Observable<any> {
        var searchParams = new SearchParameters();
        searchParams.SearchFor['userId'] = '1';
        searchParams.SearchFor['userName'] = 'xyz';

        return this.http.post(searchParams, 'users/search')
            .map(res => {
                return res;
            })
            .catch(this.handleError.bind(this));
    }

How to set initial value and auto increment in MySQL?

Use this:

ALTER TABLE users AUTO_INCREMENT=1001;

or if you haven't already added an id column, also add it

ALTER TABLE users ADD id INT UNSIGNED NOT NULL AUTO_INCREMENT,
    ADD INDEX (id);

Change the borderColor of the TextBox

You can handle WM_NCPAINT message of TextBox and draw a border on the non-client area of control if the control has focus. You can use any color to draw border:

using System;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;
public class ExTextBox : TextBox
{
    [DllImport("user32")]
    private static extern IntPtr GetWindowDC(IntPtr hwnd);
    private const int WM_NCPAINT = 0x85;
    protected override void WndProc(ref Message m)
    {
        base.WndProc(ref m);
        if (m.Msg == WM_NCPAINT && this.Focused)
        {
            var dc = GetWindowDC(Handle);
            using (Graphics g = Graphics.FromHdc(dc))
            {
                g.DrawRectangle(Pens.Red, 0, 0, Width - 1, Height - 1);
            }
        }
    }
}

Result

The painting of borders while the control is focused is completely flicker-free:

Change TextBox border color on focus

BorderColor property for TextBox

In the current post I just change the border color on focus. You can also add a BorderColor property to the control. Then you can change border-color based on your requirement at design-time or run-time. I've posted a more completed version of TextBox which has BorderColor property: in the following post:

Change Textbox border color

How to call a method in another class in Java?

You should capitalize names of your classes. After doing that do this in your school class,

Classroom cls = new Classroom();
cls.setTeacherName(newTeacherName);

Also I'd recommend you use some kind of IDE such as eclipse, which can help you with your code for instance generate getters and setters for you. Ex: right click Source -> Generate getters and setters

Webdriver findElements By xpath

Instead of

css=#container

use

css=div.container:nth-of-type(1),css=div.container:nth-of-type(2)

How to remove new line characters from data rows in mysql?

For new line characters

UPDATE table_name SET field_name = TRIM(TRAILING '\n' FROM field_name);
UPDATE table_name SET field_name = TRIM(TRAILING '\r' FROM field_name);
UPDATE table_name SET field_name = TRIM(TRAILING '\r\n' FROM field_name);

For all white space characters

UPDATE table_name SET field_name = TRIM(field_name);
UPDATE table_name SET field_name = TRIM(TRAILING '\n' FROM field_name);
UPDATE table_name SET field_name = TRIM(TRAILING '\r' FROM field_name);
UPDATE table_name SET field_name = TRIM(TRAILING '\r\n' FROM field_name);
UPDATE table_name SET field_name = TRIM(TRAILING '\t' FROM field_name);

Read more: MySQL TRIM Function

Aborting a stash pop in Git

Simple one-liner

I have always used

git reset --merge

I can't remember it ever failing.

PHP case-insensitive in_array function

  • in_array accepts these parameters : in_array(search,array,type)
  • if the search parameter is a string and the type parameter is set to TRUE, the search is case-sensitive.
  • so in order to make the search ignore the case, it would be enough to use it like this :

$a = array( 'one', 'two', 'three', 'four' );

$b = in_array( 'ONE', $a, false );

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

Looking at the source code for dumpsys and service, you can get the list of services available by executing the following:

adb shell service -l

You can then supply the service name you are interested in to dumpsys to get the specific information. For example (note that not all services provide dump info):

adb shell dumpsys activity
adb shell dumpsys cpuinfo
adb shell dumpsys battery

As you can see in the code (and in K_Anas's answer), if you call dumpsys without any service name, it will dump the info on all services in one big dump:

adb shell dumpsys

Some services can receive additional arguments on what to show which normally is explained if you supplied a -h argument, for example:

adb shell dumpsys activity -h
adb shell dumpsys window -h
adb shell dumpsys meminfo -h
adb shell dumpsys package -h
adb shell dumpsys batteryinfo -h

Why must wait() always be in synchronized block

This basically has to do with the hardware architecture (i.e. RAM and caches).

If you don't use synchronized together with wait() or notify(), another thread could enter the same block instead of waiting for the monitor to enter it. Moreover, when e.g. accessing an array without a synchronized block, another thread may not see the changement to it...actually another thread will not see any changements to it when it already has a copy of the array in the x-level cache (a.k.a. 1st/2nd/3rd-level caches) of the thread handling CPU core.

But synchronized blocks are only one side of the medal: If you actually access an object within a synchronized context from a non-synchronized context, the object still won't be synchronized even within a synchronized block, because it holds an own copy of the object in its cache. I wrote about this issues here: https://stackoverflow.com/a/21462631 and When a lock holds a non-final object, can the object's reference still be changed by another thread?

Furthermore, I'm convinced that the x-level caches are responsible for most non-reproducible runtime errors. That's because the developers usually don't learn the low-level stuff, like how CPU's work or how the memory hierarchy affects the running of applications: http://en.wikipedia.org/wiki/Memory_hierarchy

It remains a riddle why programming classes don't start with memory hierarchy and CPU architecture first. "Hello world" won't help here. ;)

DD/MM/YYYY Date format in Moment.js

You can use this

moment().format("DD/MM/YYYY");

However, this returns a date string in the specified format for today, not a moment date object. Doing the following will make it a moment date object in the format you want.

var someDateString = moment().format("DD/MM/YYYY");
var someDate = moment(someDateString, "DD/MM/YYYY");

Laravel 5.5 ajax call 419 (unknown status)

This worked for me:

$.ajaxSetup({
  headers: {
    'X-CSRF-TOKEN': "{{ csrf_token() }}"
  }
});

After this set regular AJAX call. Example:

    $.ajax({
       type:'POST',
       url:'custom_url',

       data:{name: "some name", password: "pass", email: "[email protected]"},

       success:function(response){

          // Log response
          console.log(response);

       }

    });

How to set cornerRadius for only top-left and top-right corner of a UIView?

This would be the simplest answer:

yourView.layer.cornerRadius = 8
yourView.layer.masksToBounds = true
yourView.layer.maskedCorners = [.layerMinXMinYCorner, .layerMaxXMinYCorner]

what does it mean "(include_path='.:/usr/share/pear:/usr/share/php')"?

I had a similar problem. Just to help out someone with the same issue:

My error was the user file attribute for the files in /var/www. After changing them back to the user "www-data", the problem was gone.

Choosing the correct upper and lower HSV boundaries for color detection with`cv::inRange` (OpenCV)

Here's a simple HSV color thresholder script to determine the lower/upper color ranges using trackbars for any image on the disk. Simply change the image path in cv2.imread()

enter image description here

import cv2
import numpy as np

def nothing(x):
    pass

# Load image
image = cv2.imread('1.jpg')

# Create a window
cv2.namedWindow('image')

# Create trackbars for color change
# Hue is from 0-179 for Opencv
cv2.createTrackbar('HMin', 'image', 0, 179, nothing)
cv2.createTrackbar('SMin', 'image', 0, 255, nothing)
cv2.createTrackbar('VMin', 'image', 0, 255, nothing)
cv2.createTrackbar('HMax', 'image', 0, 179, nothing)
cv2.createTrackbar('SMax', 'image', 0, 255, nothing)
cv2.createTrackbar('VMax', 'image', 0, 255, nothing)

# Set default value for Max HSV trackbars
cv2.setTrackbarPos('HMax', 'image', 179)
cv2.setTrackbarPos('SMax', 'image', 255)
cv2.setTrackbarPos('VMax', 'image', 255)

# Initialize HSV min/max values
hMin = sMin = vMin = hMax = sMax = vMax = 0
phMin = psMin = pvMin = phMax = psMax = pvMax = 0

while(1):
    # Get current positions of all trackbars
    hMin = cv2.getTrackbarPos('HMin', 'image')
    sMin = cv2.getTrackbarPos('SMin', 'image')
    vMin = cv2.getTrackbarPos('VMin', 'image')
    hMax = cv2.getTrackbarPos('HMax', 'image')
    sMax = cv2.getTrackbarPos('SMax', 'image')
    vMax = cv2.getTrackbarPos('VMax', 'image')

    # Set minimum and maximum HSV values to display
    lower = np.array([hMin, sMin, vMin])
    upper = np.array([hMax, sMax, vMax])

    # Convert to HSV format and color threshold
    hsv = cv2.cvtColor(image, cv2.COLOR_BGR2HSV)
    mask = cv2.inRange(hsv, lower, upper)
    result = cv2.bitwise_and(image, image, mask=mask)

    # Print if there is a change in HSV value
    if((phMin != hMin) | (psMin != sMin) | (pvMin != vMin) | (phMax != hMax) | (psMax != sMax) | (pvMax != vMax) ):
        print("(hMin = %d , sMin = %d, vMin = %d), (hMax = %d , sMax = %d, vMax = %d)" % (hMin , sMin , vMin, hMax, sMax , vMax))
        phMin = hMin
        psMin = sMin
        pvMin = vMin
        phMax = hMax
        psMax = sMax
        pvMax = vMax

    # Display result image
    cv2.imshow('image', result)
    if cv2.waitKey(10) & 0xFF == ord('q'):
        break

cv2.destroyAllWindows()

How do I style appcompat-v7 Toolbar like Theme.AppCompat.Light.DarkActionBar?

The cleanest way I found to do this is create a child of 'ThemeOverlay.AppCompat.Dark.ActionBar'. In the example, I set the Toolbar's background color to RED and text's color to BLUE.

<style name="MyToolbar" parent="ThemeOverlay.AppCompat.Dark.ActionBar">
    <item name="android:background">#FF0000</item>
    <item name="android:textColorPrimary">#0000FF</item>
</style>

You can then apply your theme to the toolbar:

<android.support.v7.widget.Toolbar
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_height="wrap_content"
    android:layout_width="match_parent"
    app:theme="@style/MyToolbar"
    android:minHeight="?attr/actionBarSize"/>

Xcode error "Could not find Developer Disk Image"

For iOS 10 beta 7, add the following link on the command line:

sudo ln -s /Applications/Xcode-beta.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport/10.0\ \(14A5339a\) /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport

How to convert Varchar to Double in sql?

use DECIMAL() or NUMERIC() as they are fixed precision and scale numbers.

SELECT fullName, 
       CAST(totalBal as DECIMAL(9,2)) _totalBal
FROM client_info 
ORDER BY _totalBal DESC

Swift 3 URLSession.shared() Ambiguous reference to member 'dataTask(with:completionHandler:) error (bug)

You have init'd myRequest as NSMutableURLRequest, you need this:

var URLRequest

Swift is ditching both the NSMutable... thing. Just use var for the new classes.

How to delete multiple values from a vector?

There is also subset which might be useful sometimes:

a <- sample(1:10)
bad <- c(2, 3, 5)

> subset(a, !(a %in% bad))
[1]  9  7 10  6  8  1  4

How to delete row in gridview using rowdeleting event?

     protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)
    {
        int index = GridView1.SelectedIndex;
        int id = Convert.ToInt32(GridView1.DataKeys[index].Value);
        SqlConnection con = new SqlConnection(str);
        SqlCommand com = new SqlCommand("spDelete", con);
        com.Parameters.AddWithValue("@PatientId", id);
        con.Open();
        com.ExecuteNonQuery();

Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index

What is the difference between _tmain() and main() in C++?

Ok, the question seems to have been answered fairly well, the UNICODE overload should take a wide character array as its second parameter. So if the command line parameter is "Hello" that would probably end up as "H\0e\0l\0l\0o\0\0\0" and your program would only print the 'H' before it sees what it thinks is a null terminator.

So now you may wonder why it even compiles and links.

Well it compiles because you are allowed to define an overload to a function.

Linking is a slightly more complex issue. In C, there is no decorated symbol information so it just finds a function called main. The argc and argv are probably always there as call-stack parameters just in case even if your function is defined with that signature, even if your function happens to ignore them.

Even though C++ does have decorated symbols, it almost certainly uses C-linkage for main, rather than a clever linker that looks for each one in turn. So it found your wmain and put the parameters onto the call-stack in case it is the int wmain(int, wchar_t*[]) version.

Difference between array_push() and $array[] =

When you call a function in PHP (such as array_push()), there are overheads to the call, as PHP has to look up the function reference, find its position in memory and execute whatever code it defines.

Using $arr[] = 'some value'; does not require a function call, and implements the addition straight into the data structure. Thus, when adding a lot of data it is a lot quicker and resource-efficient to use $arr[].

Abstraction vs Encapsulation in Java

Abstraction is about identifying commonalities and reducing features that you have to work with at different levels of your code.

e.g. I may have a Vehicle class. A Car would derive from a Vehicle, as would a Motorbike. I can ask each Vehicle for the number of wheels, passengers etc. and that info has been abstracted and identified as common from Cars and Motorbikes.

In my code I can often just deal with Vehicles via common methods go(), stop() etc. When I add a new Vehicle type later (e.g. Scooter) the majority of my code would remain oblivious to this fact, and the implementation of Scooter alone worries about Scooter particularities.

What is the difference between git pull and git fetch + git rebase?

It should be pretty obvious from your question that you're actually just asking about the difference between git merge and git rebase.

So let's suppose you're in the common case - you've done some work on your master branch, and you pull from origin's, which also has done some work. After the fetch, things look like this:

- o - o - o - H - A - B - C (master)
               \
                P - Q - R (origin/master)

If you merge at this point (the default behavior of git pull), assuming there aren't any conflicts, you end up with this:

- o - o - o - H - A - B - C - X (master)
               \             /
                P - Q - R --- (origin/master)

If on the other hand you did the appropriate rebase, you'd end up with this:

- o - o - o - H - P - Q - R - A' - B' - C' (master)
                          |
                          (origin/master)

The content of your work tree should end up the same in both cases; you've just created a different history leading up to it. The rebase rewrites your history, making it look as if you had committed on top of origin's new master branch (R), instead of where you originally committed (H). You should never use the rebase approach if someone else has already pulled from your master branch.

Finally, note that you can actually set up git pull for a given branch to use rebase instead of merge by setting the config parameter branch.<name>.rebase to true. You can also do this for a single pull using git pull --rebase.

JavaScript OR (||) variable assignment explanation

According to the Bill Higgins' Blog post; the Javascript logical OR assignment idiom (Feb. 2007), this behavior is true as of v1.2 (at least)

He also suggests another use for it (quoted): "lightweight normalization of cross-browser differences"

// determine upon which element a Javascript event (e) occurred
var target = /*w3c*/ e.target || /*IE*/ e.srcElement;

Get css top value as number not as string?

A slightly more practical/efficient plugin based on Ivan Castellanos' answer (which was based on M4N's answer). Using || 0 will convert Nan to 0 without the testing step.

I've also provided float and int variations to suit the intended use:

jQuery.fn.cssInt = function (prop) {
    return parseInt(this.css(prop), 10) || 0;
};

jQuery.fn.cssFloat = function (prop) {
    return parseFloat(this.css(prop)) || 0;
};

Usage:

$('#elem').cssInt('top');    // e.g. returns 123 as an int
$('#elem').cssFloat('top');  // e.g. Returns 123.45 as a float

Test fiddle on http://jsfiddle.net/TrueBlueAussie/E5LTu/

For files in directory, only echo filename (no path)

Use basename:

echo $(basename /foo/bar/stuff)

PHP Converting Integer to Date, reverse of strtotime

I guess you are asking why is 1388516401 equal to 2014-01-01...?

There is an historical reason for that. There is a 32-bit integer variable, called time_t, that keeps the count of the time elapsed since 1970-01-01 00:00:00. Its value expresses time in seconds. This means that in 2014-01-01 00:00:01 time_t will be equal to 1388516401.

This leads us for sure to another interesting fact... In 2038-01-19 03:14:07 time_t will reach 2147485547, the maximum value for a 32-bit number. Ever heard about John Titor and the Year 2038 problem? :D

Best way to integrate Python and JavaScript?

there are two projects that allow an "obvious" transition between python objects and javascript objects, with "obvious" translations from int or float to Number and str or unicode to String: PyV8 and, as one writer has already mentioned: python-spidermonkey.

there are actually two implementations of pyv8 - the original experiment was by sebastien louisel, and the second one (in active development) is by flier liu.

my interest in these projects has been to link them to pyjamas, a python-to-javascript compiler, to create a JIT python accelerator.

so there is plenty out there - it just depends what you want to do.

Spring @PropertySource using YAML

I needed to read some properties into my code and this works with spring-boot 1.3.0.RELEASE

@Autowired
private ConfigurableListableBeanFactory beanFactory;

// access a properties.yml file like properties
@Bean
public PropertySource properties() {
    PropertySourcesPlaceholderConfigurer propertySourcesPlaceholderConfigurer = new PropertySourcesPlaceholderConfigurer();
    YamlPropertiesFactoryBean yaml = new YamlPropertiesFactoryBean();
    yaml.setResources(new ClassPathResource("properties.yml"));
    propertySourcesPlaceholderConfigurer.setProperties(yaml.getObject());
    // properties need to be processed by beanfactory to be accessible after
    propertySourcesPlaceholderConfigurer.postProcessBeanFactory(beanFactory);
    return propertySourcesPlaceholderConfigurer.getAppliedPropertySources().get(PropertySourcesPlaceholderConfigurer.LOCAL_PROPERTIES_PROPERTY_SOURCE_NAME);
}

jQuery - Get Width of Element when Not Visible (Display: None)

function realWidth(obj){
    var clone = obj.clone();
    clone.css("visibility","hidden");
    $('body').append(clone);
    var width = clone.outerWidth();
    clone.remove();
    return width;
}
realWidth($("#parent").find("table:first"));

What do these operators mean (** , ^ , %, //)?

You can find all of those operators in the Python language reference, though you'll have to scroll around a bit to find them all. As other answers have said:

  • The ** operator does exponentiation. a ** b is a raised to the b power. The same ** symbol is also used in function argument and calling notations, with a different meaning (passing and receiving arbitrary keyword arguments).
  • The ^ operator does a binary xor. a ^ b will return a value with only the bits set in a or in b but not both. This one is simple!
  • The % operator is mostly to find the modulus of two integers. a % b returns the remainder after dividing a by b. Unlike the modulus operators in some other programming languages (such as C), in Python a modulus it will have the same sign as b, rather than the same sign as a. The same operator is also used for the "old" style of string formatting, so a % b can return a string if a is a format string and b is a value (or tuple of values) which can be inserted into a.
  • The // operator does Python's version of integer division. Python's integer division is not exactly the same as the integer division offered by some other languages (like C), since it rounds towards negative infinity, rather than towards zero. Together with the modulus operator, you can say that a == (a // b)*b + (a % b). In Python 2, floor division is the default behavior when you divide two integers (using the normal division operator /). Since this can be unexpected (especially when you're not picky about what types of numbers you get as arguments to a function), Python 3 has changed to make "true" (floating point) division the norm for division that would be rounded off otherwise, and it will do "floor" division only when explicitly requested. (You can also get the new behavior in Python 2 by putting from __future__ import division at the top of your files. I strongly recommend it!)

How to check for an empty object in an AngularJS view

Create a $scope function that check it and returns true or false, like a "isEmpty" function and use in your view on ng-if statement like

ng-if="isEmpty(object)"

How to get current working directory using vba?

If you really mean pure working Directory, this should suit for you.

Solution A:

Dim ParentPath As String: ParentPath = "\"
Dim ThisWorkbookPath As String
Dim ThisWorkbookPathParts, Part As Variant
Dim Count, Parts As Long

ThisWorkbookPath = ThisWorkbook.Path
ThisWorkbookPathParts = Split(ThisWorkbookPath, _
                        Application.PathSeparator)

Parts = UBound(ThisWorkbookPathParts)
Count = 0
For Each Part In ThisWorkbookPathParts
    If Count > 0 Then
        ParentPath = ParentPath & Part & "\"
    End If
    Count = Count + 1
    If Count = Parts Then Exit For
Next

MsgBox "File-Drive = " & ThisWorkbookPathParts _
       (LBound(ThisWorkbookPathParts))
MsgBox "Parent-Path = " & ParentPath

But if don't, this should be enough.

Solution B:

Dim ThisWorkbookPath As String

ThisWorkbookPath = ThisWorkbook.Path
MsgBox "Working-Directory = " & ThisWorkbookPath 

Where does PHP store the error log? (php5, apache, fastcgi, cpanel)

When configuring your error log file in php.ini, you can use an absolute path or a relative path. A relative path will be resolved based on the location of the generating script, and you'll get a log file in each directory you have scripts in. If you want all your error messages to go to the same file, use an absolute path to the file.

See more here: http://www.php.net/manual/en/ref.errorfunc.php#53025

Convert a file path to Uri in Android

Below code works fine before 18 API :-

public String getRealPathFromURI(Uri contentUri) {

        // can post image
        String [] proj={MediaStore.Images.Media.DATA};
        Cursor cursor = managedQuery( contentUri,
                        proj, // Which columns to return
                        null,       // WHERE clause; which rows to return (all rows)
                        null,       // WHERE clause selection arguments (none)
                        null); // Order-by clause (ascending by name)
        int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
        cursor.moveToFirst();

        return cursor.getString(column_index);
}

below code use on kitkat :-

public static String getPath(final Context context, final Uri uri) {

    final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;

    // DocumentProvider
    if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
        // ExternalStorageProvider
        if (isExternalStorageDocument(uri)) {
            final String docId = DocumentsContract.getDocumentId(uri);
            final String[] split = docId.split(":");
            final String type = split[0];

            if ("primary".equalsIgnoreCase(type)) {
                return Environment.getExternalStorageDirectory() + "/" + split[1];
            }

            // TODO handle non-primary volumes
        }
        // DownloadsProvider
        else if (isDownloadsDocument(uri)) {

            final String id = DocumentsContract.getDocumentId(uri);
            final Uri contentUri = ContentUris.withAppendedId(
                    Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));

            return getDataColumn(context, contentUri, null, null);
        }
        // MediaProvider
        else if (isMediaDocument(uri)) {
            final String docId = DocumentsContract.getDocumentId(uri);
            final String[] split = docId.split(":");
            final String type = split[0];

            Uri contentUri = null;
            if ("image".equals(type)) {
                contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
            } else if ("video".equals(type)) {
                contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
            } else if ("audio".equals(type)) {
                contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
            }

            final String selection = "_id=?";
            final String[] selectionArgs = new String[] {
                    split[1]
            };

            return getDataColumn(context, contentUri, selection, selectionArgs);
        }
    }
    // MediaStore (and general)
    else if ("content".equalsIgnoreCase(uri.getScheme())) {
        return getDataColumn(context, uri, null, null);
    }
    // File
    else if ("file".equalsIgnoreCase(uri.getScheme())) {
        return uri.getPath();
    }

    return null;
}

/**
 * Get the value of the data column for this Uri. This is useful for
 * MediaStore Uris, and other file-based ContentProviders.
 *
 * @param context The context.
 * @param uri The Uri to query.
 * @param selection (Optional) Filter used in the query.
 * @param selectionArgs (Optional) Selection arguments used in the query.
 * @return The value of the _data column, which is typically a file path.
 */
public static String getDataColumn(Context context, Uri uri, String selection,
        String[] selectionArgs) {

    Cursor cursor = null;
    final String column = "_data";
    final String[] projection = {
            column
    };

    try {
        cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs,
                null);
        if (cursor != null && cursor.moveToFirst()) {
            final int column_index = cursor.getColumnIndexOrThrow(column);
            return cursor.getString(column_index);
        }
    } finally {
        if (cursor != null)
            cursor.close();
    }
    return null;
}


/**
 * @param uri The Uri to check.
 * @return Whether the Uri authority is ExternalStorageProvider.
 */
public static boolean isExternalStorageDocument(Uri uri) {
    return "com.android.externalstorage.documents".equals(uri.getAuthority());
}

/**
 * @param uri The Uri to check.
 * @return Whether the Uri authority is DownloadsProvider.
 */
public static boolean isDownloadsDocument(Uri uri) {
    return "com.android.providers.downloads.documents".equals(uri.getAuthority());
}

/**
 * @param uri The Uri to check.
 * @return Whether the Uri authority is MediaProvider.
 */
public static boolean isMediaDocument(Uri uri) {
    return "com.android.providers.media.documents".equals(uri.getAuthority());
}

see below link for more info:-

https://github.com/iPaulPro/aFileChooser/blob/master/aFileChooser/src/com/ipaulpro/afilechooser/utils/FileUtils.java

INFO: No Spring WebApplicationInitializer types detected on classpath

I had this info message "No Spring WebApplicationInitializer types detected on classpath" while deploying a WAR with spring integration beans in WebLogic server. Actually, I could observe that the servlet URL returned 404 Not Found and beside that info message with a negative tone "No Spring ...etc" in Server logs, nothing else was seemingly in error in my spring config; no build or deployment errors, no complaints. Indeed, I suspected that the beans.xml (spring context XML) was actually not picked up at all and that was bound to the very specific organizing of artefacts in Oracle's jDeveloper. The solution is to play carefully with the 'contributors' and 'filters' for the WEB-INF/classes category when you edit your deployment profile under the 'deployment' topic in project properties.

Precisely, I would advise to name your spring context by the jDeveloper default "beans.xml" and place it side by side to the WEB-INF subdirectory itself (under your web Apllication source path, e.g. like <...your project path>/public_html/). Then in the WEB-INF/classes category (when editing the deployment profile) your can check the Project HTML root directory in the 'contributor' list, and then select the beans.xml in filters, and then ensure your web.xml features a context-param value like classpath:beans.xml.

Once that was fixed, I was able to progress and after some more bean config changes and implementations, the message "No Spring WebApplicationInitializer types detected on classpath" came back! Actually, I did not notice when and why exactly it came back. This second time, I added a

public class HttpGatewayInit implements WebApplicationInitializer { ... }

which implements empty inherited methods, and the whole application works fine!

...If you feel that java EE development has been getting a bit too crazy with cascades of XML configuration files (some edited manually, others through wizards) intepreted by cascades of variant initializers, let me insist that I fully share your point.

Using LIKE in an Oracle IN clause

Yes, you can use this query (Instead of 'Specialist' and 'Developer', type any strings you want separated by comma and change employees table with your table)

SELECT * FROM employees em
    WHERE EXISTS (select 1 from table(sys.dbms_debug_vc2coll('Specialist', 'Developer')) mt where em.job like ('%' || mt.column_value || '%'));

Why my query is better than the accepted answer: You don't need a CREATE TABLE permission to run it. This can be executed with just SELECT permissions.

IF EXIST C:\directory\ goto a else goto b problems windows XP batch files

@echo off

:START
rmdir temporary
cls
IF EXIST "temporary\." (echo The temporary directory exists) else echo The temporary directory doesn't exist
echo.
dir temporary /A:D
pause

echo.
echo.
echo Note the directory is not found
echo.
echo Press any key to make a temporary directory, cls, and test again
pause

Mkdir temporary
cls
IF EXIST "temporary\." (echo The temporary directory exists) else echo The temporary directory doesn't exist
echo.
dir temporary /A:D
pause
echo.
echo press any key to goto START and remove temporary directory 
pause 

goto START

How can I return the difference between two lists?

If you only want find missing values in b, you can do:

List toReturn = new ArrayList(a);
toReturn.removeAll(b);

return toReturn;

If you want to find out values which are present in either list you can execute upper code twice. With changed lists.

How to get all child inputs of a div element (jQuery)

You need

var i = $("#panel input"); 

or, depending on what exactly you want (see below)

var i = $("#panel :input"); 

the > will restrict to children, you want all descendants.

EDIT: As Nick pointed out, there's a subtle difference between $("#panel input") and $("#panel :input).

The first one will only retrieve elements of type input, that is <input type="...">, but not <textarea>, <button> and <select> elements. Thanks Nick, didn't know this myself and corrected my post accordingly. Left both options, because I guess the OP wasn't aware of that either and -technically- asked for inputs... :-)

Change Name of Import in Java, or import two classes with the same name

As the other answers already stated, Java does not provide this feature.

Implementation of this feature has been requested multiple times, e.g. as JDK-4194542: class name aliasing or JDK-4214789: Extend import to allow renaming of imported type.

From the comments:

This is not an unreasonable request, though hardly essential. The occasional use of fully qualified names is not an undue burden (unless the library really reuses the same simple names right and left, which is bad style).

In any event, it doesn't pass the bar of price/performance for a language change.

So I guess we will not see this feature in Java anytime soon :-P

The condition has length > 1 and only the first element will be used

You get the error because if can only evaluate a logical vector of length 1.

Maybe you miss the difference between & (|) and && (||). The shorter version works element-wise and the longer version uses only the first element of each vector, e.g.:

c(TRUE, TRUE) & c(TRUE, FALSE)
# [1] TRUE FALSE

# c(TRUE, TRUE) && c(TRUE, FALSE)
[1] TRUE

You don't need the if statement at all:

mut1 <- trip$Ref.y=='G' & trip$Variant.y=='T'|trip$Ref.y=='C' & trip$Variant.y=='A'
trip[mut1, "mutType"] <- "G:C to T:A"

SQL subquery with COUNT help

Assuming there is a column named business:

SELECT Business, COUNT(*) FROM eventsTable GROUP BY Business

TypeError: unhashable type: 'list' when using built-in set function

Sets require their items to be hashable. Out of types predefined by Python only the immutable ones, such as strings, numbers, and tuples, are hashable. Mutable types, such as lists and dicts, are not hashable because a change of their contents would change the hash and break the lookup code.

Since you're sorting the list anyway, just place the duplicate removal after the list is already sorted. This is easy to implement, doesn't increase algorithmic complexity of the operation, and doesn't require changing sublists to tuples:

def uniq(lst):
    last = object()
    for item in lst:
        if item == last:
            continue
        yield item
        last = item

def sort_and_deduplicate(l):
    return list(uniq(sorted(l, reverse=True)))

How to center an iframe horizontally?

According to http://www.w3schools.com/css/css_align.asp, setting the left and right margins to auto specifies that they should split the available margin equally. The result is a centered element:

margin-left: auto;margin-right: auto;

Node.js Error: connect ECONNREFUSED

The Unhandled 'error' event is referring not providing a function to the request to pass errors. Without this event the node process ends with the error instead of failing gracefully and providing actual feedback. You can set the event just before the request.write line to catch any issues:

request.on('error', function(err)
{
    console.log(err);
});

More examples below:

https://nodejs.org/api/http.html#http_http_request_options_callback

Convert Json string to Json object in Swift 4

The problem is that you thought your jsonString is a dictionary. It's not.

It's an array of dictionaries. In raw json strings, arrays begin with [ and dictionaries begin with {.


I used your json string with below code :

let string = "[{\"form_id\":3465,\"canonical_name\":\"df_SAWERQ\",\"form_name\":\"Activity 4 with Images\",\"form_desc\":null}]"
let data = string.data(using: .utf8)!
do {
    if let jsonArray = try JSONSerialization.jsonObject(with: data, options : .allowFragments) as? [Dictionary<String,Any>]
    {
       print(jsonArray) // use the json here     
    } else {
        print("bad json")
    }
} catch let error as NSError {
    print(error)
}

and I am getting the output :

[["form_desc": <null>, "form_name": Activity 4 with Images, "canonical_name": df_SAWERQ, "form_id": 3465]]

CSS: How to align vertically a "label" and "input" inside a "div"?

Wrap the label and input in another div with a defined height. This may not work in IE versions lower than 8.

position:absolute; 
top:0; bottom:0; left:0; right:0;
margin:auto;

How to submit an HTML form on loading the page?

You can try also using below script

<html>
<head>
<script>
function load()
{
document.frm1.submit()
}
</script>
</head>

<body onload="load()">
<form action="http://www.google.com" id="frm1" name="frm1">
<input type="text" value="" />
</form>
</body>
</html> 

Spring MVC Multipart Request with JSON

We've seen in our projects that a post request with JSON and files is creating a lot of confusion between the frontend and backend developers, leading to unnecessary wastage of time.

Here's a better approach: convert file bytes array to Base64 string and send it in the JSON.

public Class UserDTO {
    private String firstName;
    private String lastName;
    private FileDTO profilePic; 
}

public class FileDTO {
    private String base64;
    // just base64 string is enough. If you want, send additional details
    private String name;
    private String type;
    private String lastModified;
}

@PostMapping("/user")
public String saveUser(@RequestBody UserDTO user) {
    byte[] fileBytes = Base64Utils.decodeFromString(user.getProfilePic().getBase64());
    ....
}

JS code to convert file to base64 string:

var reader = new FileReader();
reader.readAsDataURL(file);
reader.onload = function () {

  const userDTO = {
    firstName: "John",
    lastName: "Wick",
    profilePic: {
      base64: reader.result,
      name: file.name,
      lastModified: file.lastModified,
      type: file.type
    }
  }
  
  // post userDTO
};
reader.onerror = function (error) {
  console.log('Error: ', error);
};

How to Initialize char array from a string

Weird error.

Can you test this?

const char* const S = "ABCD";
char t[] = { S[0], S[1], S[2], S[3] };
char u[] = { S[3], S[2], S[1], S[0] };

How do I obtain crash-data from my Android application?

We use our home-grown system inside the company and it serves us very well. It's an android library that send crash reports to server and server that receives reports and makes some analytics. Server groups exceptions by exception name, stacktrace, message. It helps to identify most critical issues that need to be fixed. Our service is in public beta now so everyone can try it. You can create account at http://watchcat.co or you can just take a look how it works using demo access http://watchcat.co/reports/index.php?demo.

How do you define a class of constants in Java?

My suggestions (in decreasing order of preference):

1) Don't do it. Create the constants in the actual class where they are most relevant. Having a 'bag of constants' class/interface isn't really following OO best practices.

I, and everyone else, ignore #1 from time to time. If you're going to do that then:

2) final class with private constructor This will at least prevent anyone from abusing your 'bag of constants' by extending/implementing it to get easy access to the constants. (I know you said you wouldn't do this -- but that doesn't mean someone coming along after you won't)

3) interface This will work, but not my preference giving the possible abuse mention in #2.

In general, just because these are constants doesn't mean you shouldn't still apply normal oo principles to them. If no one but one class cares about a constant - it should be private and in that class. If only tests care about a constant - it should be in a test class, not production code. If a constant is defined in multiple places (not just accidentally the same) - refactor to eliminate duplication. And so on - treat them like you would a method.

How to get "wc -l" to print just the number of lines without file name?

Obviously, there are a lot of solutions to this. Here is another one though:

wc -l somefile | tr -d "[:alpha:][:blank:][:punct:]"

This only outputs the number of lines, but the trailing newline character (\n) is present, if you don't want that either, replace [:blank:] with [:space:].

Angular 2 Sibling Component Communication

Updated to rc.4: When trying to get data passed between sibling components in angular 2, The simplest way right now (angular.rc.4) is to take advantage of angular2's hierarchal dependency injection and create a shared service.

Here would be the service:

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

@Injectable()
export class SharedService {
    dataArray: string[] = [];

    insertData(data: string){
        this.dataArray.unshift(data);
    }
}

Now, here would be the PARENT component

import {Component} from '@angular/core';
import {SharedService} from './shared.service';
import {ChildComponent} from './child.component';
import {ChildSiblingComponent} from './child-sibling.component';
@Component({
    selector: 'parent-component',
    template: `
        <h1>Parent</h1>
        <div>
            <child-component></child-component>
            <child-sibling-component></child-sibling-component>
        </div>
    `,
    providers: [SharedService],
    directives: [ChildComponent, ChildSiblingComponent]
})
export class parentComponent{

} 

and its two children

child 1

import {Component, OnInit} from '@angular/core';
import {SharedService} from './shared.service'

@Component({
    selector: 'child-component',
    template: `
        <h1>I am a child</h1>
        <div>
            <ul *ngFor="#data in data">
                <li>{{data}}</li>
            </ul>
        </div>
    `
})
export class ChildComponent implements OnInit{
    data: string[] = [];
    constructor(
        private _sharedService: SharedService) { }
    ngOnInit():any {
        this.data = this._sharedService.dataArray;
    }
}

child 2 (It's sibling)

import {Component} from 'angular2/core';
import {SharedService} from './shared.service'

@Component({
    selector: 'child-sibling-component',
    template: `
        <h1>I am a child</h1>
        <input type="text" [(ngModel)]="data"/>
        <button (click)="addData()"></button>
    `
})
export class ChildSiblingComponent{
    data: string = 'Testing data';
    constructor(
        private _sharedService: SharedService){}
    addData(){
        this._sharedService.insertData(this.data);
        this.data = '';
    }
}

NOW: Things to take note of when using this method.

  1. Only include the service provider for the shared service in the PARENT component and NOT the children.
  2. You still have to include constructors and import the service in the children
  3. This answer was originally answered for an early angular 2 beta version. All that has changed though are the import statements, so that is all you need to update if you used the original version by chance.

Elegant solution for line-breaks (PHP)

\n didn't work for me. the \n appear in the bodytext of the email I was sending.. this is how I resolved it.

str_pad($input, 990); //so that the spaces will pad out to the 990 cut off.

Using 'sudo apt-get install build-essentials'

Try

sudo apt-get update
sudo apt-get install build-essential

(If I recall correctly the package name is without the extra s at the end).

Equal height rows in a flex container

you can do it by fixing the height of "P" tag or fixing the height of "list-item".

I have done by fixing the height of "P"

and overflow should be hidden.

_x000D_
_x000D_
.list{_x000D_
  display: flex;_x000D_
  flex-wrap: wrap;_x000D_
  max-width: 500px;_x000D_
}_x000D_
_x000D_
.list-item{_x000D_
  background-color: #ccc;_x000D_
  display: flex;_x000D_
  padding: 0.5em;_x000D_
  width: 25%;_x000D_
  margin-right: 1%;_x000D_
  margin-bottom: 20px;_x000D_
}_x000D_
.list-content{_x000D_
  width: 100%;_x000D_
}_x000D_
p{height:100px;overflow:hidden;}
_x000D_
<ul class="list">_x000D_
  <li class="list-item">_x000D_
    <div class="list-content">_x000D_
    <h2>box 1</h2>_x000D_
    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. </p>_x000D_
    </div>_x000D_
  </li>_x000D_
  <li class="list-item">_x000D_
    <div class="list-content">_x000D_
    <h3>box 2</h3>_x000D_
    <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit.</p>_x000D_
    </div>_x000D_
  </li>_x000D_
  _x000D_
    <li class="list-item">_x000D_
    <div class="list-content">_x000D_
    <h3>box 2</h3>_x000D_
    <p>Lorem ipsum dolor</p>_x000D_
    </div>_x000D_
  </li>_x000D_
  _x000D_
    <li class="list-item">_x000D_
    <div class="list-content">_x000D_
    <h3>box 2</h3>_x000D_
    <p>Lorem ipsum dolor</p>_x000D_
    </div>_x000D_
  </li>_x000D_
  <li class="list-item">_x000D_
    <div class="list-content">_x000D_
      <h1>h1</h1>_x000D_
    </div>_x000D_
  </li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

Browser can't access/find relative resources like CSS, images and links when calling a Servlet which forwards to a JSP

If you are using Spring MVC, then you need to declare default action servlet for static contents. Add the following entries in spring-action-servlet.xml. It worked for me.

NOTE: keep all the static contents outside WEB-INF.

<!-- Enable annotation-based controllers using @Controller annotations -->
<bean id="annotationUrlMapping" class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping">
    <property name="order" value="0" />
</bean>

<bean id="controllerClassNameHandlerMapping" class="org.springframework.web.servlet.mvc.support.ControllerClassNameHandlerMapping">
    <property name="order" value="1" />
</bean>

<bean id="annotationMethodHandlerAdapter" class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter"/>

How do I get SUM function in MySQL to return '0' if no values are found?

Use IFNULL or COALESCE:

SELECT IFNULL(SUM(Column1), 0) AS total FROM...

SELECT COALESCE(SUM(Column1), 0) AS total FROM...

The difference between them is that IFNULL is a MySQL extension that takes two arguments, and COALESCE is a standard SQL function that can take one or more arguments. When you only have two arguments using IFNULL is slightly faster, though here the difference is insignificant since it is only called once.

hasNext in Python iterators?

In addition to all the mentions of StopIteration, the Python "for" loop simply does what you want:

>>> it = iter("hello")
>>> for i in it:
...     print i
...
h
e
l
l
o

Scroll Element into View with Selenium

You may want to visit page Scroll Web elements and Web page- Selenium WebDriver using Javascript:

public static void main(String[] args) throws Exception {

    // TODO Auto-generated method stub
    FirefoxDriver ff = new FirefoxDriver();
    ff.get("http://toolsqa.com");
    Thread.sleep(5000);
    ff.executeScript("document.getElementById('text-8').scrollIntoView(true);");
}

New lines inside paragraph in README.md

Interpreting newlines as <br /> used to be a feature of Github-flavored markdown, but the most recent help document no longer lists this feature.

Fortunately, you can do it manually. The easiest way is to ensure that each line ends with two spaces. So, change

a
b
c

into

a__
b__
c

(where _ is a blank space).

Or, you can add explicit <br /> tags.

a <br />
b <br />
c

Setting an environment variable before a command in Bash is not working for the second command in a pipe

Use env.

For example, env FOO=BAR command. Note that the environment variables will be restored/unchanged again when command finishes executing.

Just be careful about about shell substitution happening, i.e. if you want to reference $FOO explicitly on the same command line, you may need to escape it so that your shell interpreter doesn't perform the substitution before it runs env.

$ export FOO=BAR
$ env FOO=FUBAR bash -c 'echo $FOO'
FUBAR
$ echo $FOO
BAR

Automatically pass $event with ng-click?

Add a $event to the ng-click, for example:

<button type="button" ng-click="saveOffer($event)" accesskey="S"></button>

Then the jQuery.Event was passed to the callback:

enter image description here

How to get number of video views with YouTube API?

Here is a small code snippet to get Youtube video views from URL using Javascript

Demo of below code

    function videoViews() {
var rex = /[a-zA-Z0-9\-\_]{11}/,
    videoUrl = $('input').val() === '' ? alert('Enter a valid Url'):$('input').val(),
    videoId = videoUrl.match(rex),
    jsonUrl = 'http://gdata.youtube.com/feeds/api/videos/' + videoId + '?v=2&alt=json',
   embedUrl = '//www.youtube.com/embed/' + videoId,
   embedCode = '<iframe width="350" height="197" src="' + embedUrl + '" frameborder="0" allowfullscreen></iframe>'


//Get Views from JSON
$.getJSON(jsonUrl, function (videoData) {
    var videoJson = JSON.stringify(videoData),
        vidJson = JSON.parse(videoJson),
        views = vidJson.entry.yt$statistics.viewCount;
    $('.views').text(views);
});

//Embed Video
$('.videoembed').html(embedCode);}

How to test Spring Data repositories?

With JUnit5 and @DataJpaTest test will look like (kotlin code):

@DataJpaTest
@ExtendWith(value = [SpringExtension::class])
class ActivityJpaTest {

    @Autowired
    lateinit var entityManager: TestEntityManager

    @Autowired
    lateinit var myEntityRepository: MyEntityRepository

    @Test
    fun shouldSaveEntity() {
        // when
        val savedEntity = myEntityRepository.save(MyEntity(1, "test")

        // then 
        Assertions.assertNotNull(entityManager.find(MyEntity::class.java, savedEntity.id))
    }
}

You could use TestEntityManager from org.springframework.boot.test.autoconfigure.orm.jpa.TestEntityManager package in order to validate entity state.

Pandas read_sql with parameters

The read_sql docs say this params argument can be a list, tuple or dict (see docs).

To pass the values in the sql query, there are different syntaxes possible: ?, :1, :name, %s, %(name)s (see PEP249).
But not all of these possibilities are supported by all database drivers, which syntax is supported depends on the driver you are using (psycopg2 in your case I suppose).

In your second case, when using a dict, you are using 'named arguments', and according to the psycopg2 documentation, they support the %(name)s style (and so not the :name I suppose), see http://initd.org/psycopg/docs/usage.html#query-parameters.
So using that style should work:

df = psql.read_sql(('select "Timestamp","Value" from "MyTable" '
                     'where "Timestamp" BETWEEN %(dstart)s AND %(dfinish)s'),
                   db,params={"dstart":datetime(2014,6,24,16,0),"dfinish":datetime(2014,6,24,17,0)},
                   index_col=['Timestamp'])

How to run a C# application at Windows startup?

Try this code:

private void RegisterInStartup(bool isChecked)
{
    RegistryKey registryKey = Registry.CurrentUser.OpenSubKey
            ("SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run", true);
    if (isChecked)
    {
        registryKey.SetValue("ApplicationName", Application.ExecutablePath);
    }
    else
    {
        registryKey.DeleteValue("ApplicationName");
    }
}

Source (dead): http://www.dotnetthoughts.net/2010/09/26/run-the-application-at-windows-startup/

Archived link: https://web.archive.org/web/20110104113608/http://www.dotnetthoughts.net/2010/09/26/run-the-application-at-windows-startup/

base64 encoded images in email signatures

Important

My answer below shows how to embed images using data URIs. This is useful for the web, but will not work reliably for most email clients. For email purposes be sure to read Shadow2531's answer.


Base-64 data is legal in an img tag and I believe your question is how to properly insert such an image tag.

You can use an online tool or a few lines of code to generate the base 64 string.

The syntax to source the image from inline data is:

<img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUA
AAAFCAYAAACNbyblAAAAHElEQVQI12P4//8/w38GIAXDIBKE0DHxgljNBAAO
9TXL0Y4OHwAAAABJRU5ErkJggg==" alt="Red dot">

http://en.wikipedia.org/wiki/Data_URI_scheme

"Proxy server connection failed" in google chrome

Internet explorer has a reset to factory button and luckily so does chrome! try the link below and let us know. the other option is to stop chrome and delete the c:\users\%username%\appdata\local\google folder entirely then reinstall chrome but this will loose all you local settings and data.

Google doc on how to factory reset: https://support.google.com/chrome/answer/3296214?hl=en

What's the safest way to iterate through the keys of a Perl hash?

A few miscellaneous thoughts on this topic:

  1. There is nothing unsafe about any of the hash iterators themselves. What is unsafe is modifying the keys of a hash while you're iterating over it. (It's perfectly safe to modify the values.) The only potential side-effect I can think of is that values returns aliases which means that modifying them will modify the contents of the hash. This is by design but may not be what you want in some circumstances.
  2. John's accepted answer is good with one exception: the documentation is clear that it is not safe to add keys while iterating over a hash. It may work for some data sets but will fail for others depending on the hash order.
  3. As already noted, it is safe to delete the last key returned by each. This is not true for keys as each is an iterator while keys returns a list.

jQuery select2 get value of select tag?

Solution :

var my_veriable = $('#your_select2_id').select2().val();
var my_last_veriable = my_veriable.toString();

Java JSON serialization - best practice

Are you tied to this library? Google Gson is very popular. I have myself not used it with Generics but their front page says Gson considers support for Generics very important.

Can't include C++ headers like vector in Android NDK

Let me add a little to Sebastian Roth's answer.

Your project can be compiled by using ndk-build in the command line after adding the code Sebastian had posted. But as for me, there were syntax errors in Eclipse, and I didn't have code completion.

Note that your project must be converted to a C/C++ project.

How to convert a C/C++ project

To fix this issue right-click on your project, click Properties

Choose C/C++ General -> Paths and Symbols and include the ${ANDROID_NDK}/sources/cxx-stl/stlport/stlport to Include directories

Click Yes when a dialog shows up.

Dialog

Before

Before

After

After

Update #1

GNU C. Add directories, rebuild. There won't be any errors in C source files
GNU C++. Add directories, rebuild. There won't be any errors in CPP source files.

To check if string contains particular word

.contains() is perfectly valid and a good way to check.

(http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/String.html#contains(java.lang.CharSequence))

Since you didn't post the error, I guess d is either null or you are getting the "Cannot refer to a non-final variable inside an inner class defined in a different method" error.

To make sure it's not null, first check for null in the if statement. If it's the other error, make sure d is declared as final or is a member variable of your class. Ditto for c.

How to resolve "Server Error in '/' Application" error?

You may get this error when trying to browse an ASP.NET application.

The debug information shows that "This error can be caused by a virtual directory not being configured as an application in IIS."

However, this error occurs primarily out of two scenarios.

  1. When you create an new web application using Visual Studio .NET, it automatically creates the virtual directory and configures it as an application. However, if you manually create the virtual directory and it is not configured as an application, then you will not be able to browse the application and may get the above error. The debug information you get as mentioned above, is applicable to this scenario.

To resolve it, right click on the virtual directory - select properties and then click on "Create" next to the "Application" Label and the text box. It will automatically create the "application" using the virtual directory's name. Now the application can be accessed.

  1. When you have sub-directories in your application, you can have web.config file for the sub-directory. However, there are certain properties which cannot be set in the web.config of the sub-directory such as authentication, session state (you may see that the error message shows the line number where the authentication or session state is declared in the web.config of the sub-directory). The reason is, these settings cannot be overridden at the sub-directory level unless the sub-directory is also configured as an application (as mentioned in the above point).

Mostly, we have the practice of adding web.config in the sub-directory if we want to protect access to the sub-directory files (say, the directory is admin and we wish to protect the admin pages from unauthorized users).

Where to download visual studio express 2005?

For somebody like me who lands onto this page from Google ages after this question had been posted, you can find VS2005 here: http://apdubey.blogspot.com/2009/04/microsoft-visual-studio-2005-express.html

EDIT: In case that blog dies, here are the links from the blog.

All the bellow files are more them 400MB.

Visual Web Developer 2005 Express Edition
449,848 KB
.IMG File | .ISO File

Visual Basic 2005 Express Edition
445,282 KB
.IMG File | .ISO File

Visual C# 2005 Express Edition
445,282 KB
.IMG File | .ISO File

Visual C++ 2005 Express Edition
474,686 KB
.IMG File | .ISO File

Visual J# 2005 Express Edition
448,702 KB
.IMG File | .ISO File

Detect when browser receives file download

The question is to have a ‘waiting’ indicator while a file is generated and then return to normal once the file is downloading. The way I like todo this is using a hidden iFrame and hook the frame’s onload event to let my page know when download starts. BUT onload does not fire in IE for file downloads (like with the attachment header token). Polling the server works, but I dislike the extra complexity. So here is what I do:

  • Target the hidden iFrame as usual.
  • Generate the content. Cache it with an absolute timeout in 2 minutes.
  • Send a javascript redirect back to the calling client, essentially calling the generator page a second time. NOTE: this will cause the onload event to fire in IE because it's acting like a regular page.
  • Remove the content from the cache and send it to the client.

Disclaimer, don’t do this on a busy site, because of the caching could add up. But really, if your sites that busy the long running process will starve you of threads anyways.

Here is what the codebehind looks like, which is all you really need.

public partial class Download : System.Web.UI.Page
{
    protected System.Web.UI.HtmlControls.HtmlControl Body;

    protected void Page_Load( object sender, EventArgs e )
    {
        byte[ ] data;
        string reportKey = Session.SessionID + "_Report";

        // Check is this page request to generate the content
        //    or return the content (data query string defined)
        if ( Request.QueryString[ "data" ] != null )
        {
            // Get the data and remove the cache
            data = Cache[ reportKey ] as byte[ ];
            Cache.Remove( reportKey );

            if ( data == null )                    
                // send the user some information
                Response.Write( "Javascript to tell user there was a problem." );                    
            else
            {
                Response.CacheControl = "no-cache";
                Response.AppendHeader( "Pragma", "no-cache" );
                Response.Buffer = true;

                Response.AppendHeader( "content-disposition", "attachment; filename=Report.pdf" );
                Response.AppendHeader( "content-size", data.Length.ToString( ) );
                Response.BinaryWrite( data );
            }
            Response.End();                
        }
        else
        {
            // Generate the data here. I am loading a file just for an example
            using ( System.IO.FileStream stream = new System.IO.FileStream( @"C:\1.pdf", System.IO.FileMode.Open ) )
                using ( System.IO.BinaryReader reader = new System.IO.BinaryReader( stream ) )
                {
                    data = new byte[ reader.BaseStream.Length ];
                    reader.Read( data, 0, data.Length );
                }

            // Store the content for retrieval              
            Cache.Insert( reportKey, data, null, DateTime.Now.AddMinutes( 5 ), TimeSpan.Zero );

            // This is the key bit that tells the frame to reload this page 
            //   and start downloading the content. NOTE: Url has a query string 
            //   value, so that the content isn't generated again.
            Body.Attributes.Add("onload", "window.location = 'binary.aspx?data=t'");
        }
    }

Address already in use: JVM_Bind java

Address already in use: JVM_Bind

means that some other application is already listening on the port your current application is trying to bind.

what you need to do is, either change the port for your current application or better; just find out the already running application and kill it.

on Linux you can find the application pid by using,

netstat -tulpn

How can I generate a 6 digit unique number?

$characters = '123456789';
$charactersLength = strlen($characters);
$randomString = '';
for ($i = 0; $i < 6; $i++) {
    $randomString .= $characters[rand(0, $charactersLength - 1)];
}
$pin=$randomString; 

Undefined reference to `sin`

You have compiled your code with references to the correct math.h header file, but when you attempted to link it, you forgot the option to include the math library. As a result, you can compile your .o object files, but not build your executable.

As Paul has already mentioned add "-lm" to link with the math library in the step where you are attempting to generate your executable.

In the comment, linuxD asks:

Why for sin() in <math.h>, do we need -lm option explicitly; but, not for printf() in <stdio.h>?

Because both these functions are implemented as part of the "Single UNIX Specification". This history of this standard is interesting, and is known by many names (IEEE Std 1003.1, X/Open Portability Guide, POSIX, Spec 1170).

This standard, specifically separates out the "Standard C library" routines from the "Standard C Mathematical Library" routines (page 277). The pertinent passage is copied below:

Standard C Library

The Standard C library is automatically searched by cc to resolve external references. This library supports all of the interfaces of the Base System, as defined in Volume 1, except for the Math Routines.

Standard C Mathematical Library

This library supports the Base System math routines, as defined in Volume 1. The cc option -lm is used to search this library.

The reasoning behind this separation was influenced by a number of factors:

  1. The UNIX wars led to increasing divergence from the original AT&T UNIX offering.
  2. The number of UNIX platforms added difficulty in developing software for the operating system.
  3. An attempt to define the lowest common denominator for software developers was launched, called 1988 POSIX.
  4. Software developers programmed against the POSIX standard to provide their software on "POSIX compliant systems" in order to reach more platforms.
  5. UNIX customers demanded "POSIX compliant" UNIX systems to run the software.

The pressures that fed into the decision to put -lm in a different library probably included, but are not limited to:

  1. It seems like a good way to keep the size of libc down, as many applications don't use functions embedded in the math library.
  2. It provides flexibility in math library implementation, where some math libraries rely on larger embedded lookup tables while others may rely on smaller lookup tables (computing solutions).
  3. For truly size constrained applications, it permits reimplementations of the math library in a non-standard way (like pulling out just sin() and putting it in a custom built library.

In any case, it is now part of the standard to not be automatically included as part of the C language, and that's why you must add -lm.

How to use java.net.URLConnection to fire and handle HTTP requests?

First a disclaimer beforehand: the posted code snippets are all basic examples. You'll need to handle trivial IOExceptions and RuntimeExceptions like NullPointerException, ArrayIndexOutOfBoundsException and consorts yourself.


Preparing

We first need to know at least the URL and the charset. The parameters are optional and depend on the functional requirements.

String url = "http://example.com";
String charset = "UTF-8";  // Or in Java 7 and later, use the constant: java.nio.charset.StandardCharsets.UTF_8.name()
String param1 = "value1";
String param2 = "value2";
// ...

String query = String.format("param1=%s&param2=%s", 
     URLEncoder.encode(param1, charset), 
     URLEncoder.encode(param2, charset));

The query parameters must be in name=value format and be concatenated by &. You would normally also URL-encode the query parameters with the specified charset using URLEncoder#encode().

The String#format() is just for convenience. I prefer it when I would need the String concatenation operator + more than twice.


Firing an HTTP GET request with (optionally) query parameters

It's a trivial task. It's the default request method.

URLConnection connection = new URL(url + "?" + query).openConnection();
connection.setRequestProperty("Accept-Charset", charset);
InputStream response = connection.getInputStream();
// ...

Any query string should be concatenated to the URL using ?. The Accept-Charset header may hint the server what encoding the parameters are in. If you don't send any query string, then you can leave the Accept-Charset header away. If you don't need to set any headers, then you can even use the URL#openStream() shortcut method.

InputStream response = new URL(url).openStream();
// ...

Either way, if the other side is an HttpServlet, then its doGet() method will be called and the parameters will be available by HttpServletRequest#getParameter().

For testing purposes, you can print the response body to stdout as below:

try (Scanner scanner = new Scanner(response)) {
    String responseBody = scanner.useDelimiter("\\A").next();
    System.out.println(responseBody);
}

Firing an HTTP POST request with query parameters

Setting the URLConnection#setDoOutput() to true implicitly sets the request method to POST. The standard HTTP POST as web forms do is of type application/x-www-form-urlencoded wherein the query string is written to the request body.

URLConnection connection = new URL(url).openConnection();
connection.setDoOutput(true); // Triggers POST.
connection.setRequestProperty("Accept-Charset", charset);
connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=" + charset);

try (OutputStream output = connection.getOutputStream()) {
    output.write(query.getBytes(charset));
}

InputStream response = connection.getInputStream();
// ...

Note: whenever you'd like to submit a HTML form programmatically, don't forget to take the name=value pairs of any <input type="hidden"> elements into the query string and of course also the name=value pair of the <input type="submit"> element which you'd like to "press" programmatically (because that's usually been used in the server side to distinguish if a button was pressed and if so, which one).

You can also cast the obtained URLConnection to HttpURLConnection and use its HttpURLConnection#setRequestMethod() instead. But if you're trying to use the connection for output you still need to set URLConnection#setDoOutput() to true.

HttpURLConnection httpConnection = (HttpURLConnection) new URL(url).openConnection();
httpConnection.setRequestMethod("POST");
// ...

Either way, if the other side is an HttpServlet, then its doPost() method will be called and the parameters will be available by HttpServletRequest#getParameter().


Actually firing the HTTP request

You can fire the HTTP request explicitly with URLConnection#connect(), but the request will automatically be fired on demand when you want to get any information about the HTTP response, such as the response body using URLConnection#getInputStream() and so on. The above examples does exactly that, so the connect() call is in fact superfluous.


Gathering HTTP response information

  1. HTTP response status:

You need an HttpURLConnection here. Cast it first if necessary.

    int status = httpConnection.getResponseCode();
  1. HTTP response headers:

     for (Entry<String, List<String>> header : connection.getHeaderFields().entrySet()) {
         System.out.println(header.getKey() + "=" + header.getValue());
     }
    
  2. HTTP response encoding:

When the Content-Type contains a charset parameter, then the response body is likely text based and we'd like to process the response body with the server-side specified character encoding then.

    String contentType = connection.getHeaderField("Content-Type");
    String charset = null;

    for (String param : contentType.replace(" ", "").split(";")) {
        if (param.startsWith("charset=")) {
            charset = param.split("=", 2)[1];
            break;
        }
    }

    if (charset != null) {
        try (BufferedReader reader = new BufferedReader(new InputStreamReader(response, charset))) {
            for (String line; (line = reader.readLine()) != null;) {
                // ... System.out.println(line) ?
            }
        }
    } else {
        // It's likely binary content, use InputStream/OutputStream.
    }

Maintaining the session

The server side session is usually backed by a cookie. Some web forms require that you're logged in and/or are tracked by a session. You can use the CookieHandler API to maintain cookies. You need to prepare a CookieManager with a CookiePolicy of ACCEPT_ALL before sending all HTTP requests.

// First set the default cookie manager.
CookieHandler.setDefault(new CookieManager(null, CookiePolicy.ACCEPT_ALL));

// All the following subsequent URLConnections will use the same cookie manager.
URLConnection connection = new URL(url).openConnection();
// ...

connection = new URL(url).openConnection();
// ...

connection = new URL(url).openConnection();
// ...

Note that this is known to not always work properly in all circumstances. If it fails for you, then best is to manually gather and set the cookie headers. You basically need to grab all Set-Cookie headers from the response of the login or the first GET request and then pass this through the subsequent requests.

// Gather all cookies on the first request.
URLConnection connection = new URL(url).openConnection();
List<String> cookies = connection.getHeaderFields().get("Set-Cookie");
// ...

// Then use the same cookies on all subsequent requests.
connection = new URL(url).openConnection();
for (String cookie : cookies) {
    connection.addRequestProperty("Cookie", cookie.split(";", 2)[0]);
}
// ...

The split(";", 2)[0] is there to get rid of cookie attributes which are irrelevant for the server side like expires, path, etc. Alternatively, you could also use cookie.substring(0, cookie.indexOf(';')) instead of split().


Streaming mode

The HttpURLConnection will by default buffer the entire request body before actually sending it, regardless of whether you've set a fixed content length yourself using connection.setRequestProperty("Content-Length", contentLength);. This may cause OutOfMemoryExceptions whenever you concurrently send large POST requests (e.g. uploading files). To avoid this, you would like to set the HttpURLConnection#setFixedLengthStreamingMode().

httpConnection.setFixedLengthStreamingMode(contentLength);

But if the content length is really not known beforehand, then you can make use of chunked streaming mode by setting the HttpURLConnection#setChunkedStreamingMode() accordingly. This will set the HTTP Transfer-Encoding header to chunked which will force the request body being sent in chunks. The below example will send the body in chunks of 1KB.

httpConnection.setChunkedStreamingMode(1024);

User-Agent

It can happen that a request returns an unexpected response, while it works fine with a real web browser. The server side is probably blocking requests based on the User-Agent request header. The URLConnection will by default set it to Java/1.6.0_19 where the last part is obviously the JRE version. You can override this as follows:

connection.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/41.0.2228.0 Safari/537.36"); // Do as if you're using Chrome 41 on Windows 7.

Use the User-Agent string from a recent browser.


Error handling

If the HTTP response code is 4nn (Client Error) or 5nn (Server Error), then you may want to read the HttpURLConnection#getErrorStream() to see if the server has sent any useful error information.

InputStream error = ((HttpURLConnection) connection).getErrorStream();

If the HTTP response code is -1, then something went wrong with connection and response handling. The HttpURLConnection implementation is in older JREs somewhat buggy with keeping connections alive. You may want to turn it off by setting the http.keepAlive system property to false. You can do this programmatically in the beginning of your application by:

System.setProperty("http.keepAlive", "false");

Uploading files

You'd normally use multipart/form-data encoding for mixed POST content (binary and character data). The encoding is in more detail described in RFC2388.

String param = "value";
File textFile = new File("/path/to/file.txt");
File binaryFile = new File("/path/to/file.bin");
String boundary = Long.toHexString(System.currentTimeMillis()); // Just generate some unique random value.
String CRLF = "\r\n"; // Line separator required by multipart/form-data.
URLConnection connection = new URL(url).openConnection();
connection.setDoOutput(true);
connection.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);

try (
    OutputStream output = connection.getOutputStream();
    PrintWriter writer = new PrintWriter(new OutputStreamWriter(output, charset), true);
) {
    // Send normal param.
    writer.append("--" + boundary).append(CRLF);
    writer.append("Content-Disposition: form-data; name=\"param\"").append(CRLF);
    writer.append("Content-Type: text/plain; charset=" + charset).append(CRLF);
    writer.append(CRLF).append(param).append(CRLF).flush();

    // Send text file.
    writer.append("--" + boundary).append(CRLF);
    writer.append("Content-Disposition: form-data; name=\"textFile\"; filename=\"" + textFile.getName() + "\"").append(CRLF);
    writer.append("Content-Type: text/plain; charset=" + charset).append(CRLF); // Text file itself must be saved in this charset!
    writer.append(CRLF).flush();
    Files.copy(textFile.toPath(), output);
    output.flush(); // Important before continuing with writer!
    writer.append(CRLF).flush(); // CRLF is important! It indicates end of boundary.

    // Send binary file.
    writer.append("--" + boundary).append(CRLF);
    writer.append("Content-Disposition: form-data; name=\"binaryFile\"; filename=\"" + binaryFile.getName() + "\"").append(CRLF);
    writer.append("Content-Type: " + URLConnection.guessContentTypeFromName(binaryFile.getName())).append(CRLF);
    writer.append("Content-Transfer-Encoding: binary").append(CRLF);
    writer.append(CRLF).flush();
    Files.copy(binaryFile.toPath(), output);
    output.flush(); // Important before continuing with writer!
    writer.append(CRLF).flush(); // CRLF is important! It indicates end of boundary.

    // End of multipart/form-data.
    writer.append("--" + boundary + "--").append(CRLF).flush();
}

If the other side is an HttpServlet, then its doPost() method will be called and the parts will be available by HttpServletRequest#getPart() (note, thus not getParameter() and so on!). The getPart() method is however relatively new, it's introduced in Servlet 3.0 (Glassfish 3, Tomcat 7, etc). Prior to Servlet 3.0, your best choice is using Apache Commons FileUpload to parse a multipart/form-data request. Also see this answer for examples of both the FileUpload and the Servelt 3.0 approaches.


Dealing with untrusted or misconfigured HTTPS sites

Sometimes you need to connect an HTTPS URL, perhaps because you're writing a web scraper. In that case, you may likely face a javax.net.ssl.SSLException: Not trusted server certificate on some HTTPS sites who doesn't keep their SSL certificates up to date, or a java.security.cert.CertificateException: No subject alternative DNS name matching [hostname] found or javax.net.ssl.SSLProtocolException: handshake alert: unrecognized_name on some misconfigured HTTPS sites.

The following one-time-run static initializer in your web scraper class should make HttpsURLConnection more lenient as to those HTTPS sites and thus not throw those exceptions anymore.

static {
    TrustManager[] trustAllCertificates = new TrustManager[] {
        new X509TrustManager() {
            @Override
            public X509Certificate[] getAcceptedIssuers() {
                return null; // Not relevant.
            }
            @Override
            public void checkClientTrusted(X509Certificate[] certs, String authType) {
                // Do nothing. Just allow them all.
            }
            @Override
            public void checkServerTrusted(X509Certificate[] certs, String authType) {
                // Do nothing. Just allow them all.
            }
        }
    };

    HostnameVerifier trustAllHostnames = new HostnameVerifier() {
        @Override
        public boolean verify(String hostname, SSLSession session) {
            return true; // Just allow them all.
        }
    };

    try {
        System.setProperty("jsse.enableSNIExtension", "false");
        SSLContext sc = SSLContext.getInstance("SSL");
        sc.init(null, trustAllCertificates, new SecureRandom());
        HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());
        HttpsURLConnection.setDefaultHostnameVerifier(trustAllHostnames);
    }
    catch (GeneralSecurityException e) {
        throw new ExceptionInInitializerError(e);
    }
}

Last words

The Apache HttpComponents HttpClient is much more convenient in this all :)


Parsing and extracting HTML

If all you want is parsing and extracting data from HTML, then better use a HTML parser like Jsoup

Should I use SVN or Git?

I would opt for SVN since it is more widely spread and better known.

I guess, Git would be better for Linux user.

What happens when a duplicate key is put into a HashMap?

Associates the specified value with the specified key in this map. If the map previously contained a mapping for the key, the old value is replaced.

What does "if (rs.next())" mean?

Since Result Set is an interface, When you obtain a reference to a ResultSet through a JDBC call, you are getting an instance of a class that implements the ResultSet interface. This class provides concrete implementations of all of the ResultSet methods.

Interfaces are used to divorce implementation from, well, interface. This allows the creation of generic algorithms and the abstraction of object creation. For example, JDBC drivers for different databases will return different ResultSet implementations, but you don't have to change your code to make it work with the different drivers

In very short, if your ResultSet contains result, then using rs.next return true if you have recordset else it returns false.

Append text to textarea with javascript

Tray to add text with html value to textarea but it wil not works

value :

$(document).on('click', '.edit_targets_btn', function() {
            $('#add_edit_targets').modal('show');
            $('#add_edit_targets_form')[0].reset();
            $('#targets_modal_title').text('Doel bijwerken');
            $('#action').val('targets_update');
            $('#targets_submit_btn').val('Opslaan');

            $('#callcenter_targets_id').val($(this).attr("callcenter_targets_id"));
            $('#targets_title').val($(this).attr("title"));
            $("#targets_content").append($(this).attr("content"));

            tinymce.init({
                selector: '#targets_content',
                setup: function (editor) {
                    editor.on('change', function () {
                        tinymce.triggerSave();
                    });
                },
                browser_spellcheck : true,
                plugins: ['advlist autolink lists image charmap print preview anchor', 'searchreplace visualblocks code fullscreen', 'insertdatetime media table paste code help wordcount', 'autoresize'],
                toolbar: 'undo redo | formatselect | ' + ' bold italic backcolor | alignleft aligncenter ' + ' alignright alignjustify | bullist numlist outdent indent |' + ' removeformat | image | help',
                relative_urls : false,
                remove_script_host : false,
                image_list: [<?php $stmt = $db->query('SELECT * FROM images WHERE users_id = ' . $get_user_users_id); foreach ($stmt as $row) { ?>{title: '<?=$row['name']?>', value: '<?=$imgurl?>/image_uploads/<?=$row['src']?>'},<?php } ?>],
                min_height: 250,
                branding: false
            });
        });

Which loop is faster, while or for?

In C#, the For loop is slightly faster.

For loop average about 2.95 to 3.02 ms.

The While loop averaged about 3.05 to 3.37 ms.

Quick little console app to prove:

 class Program
    {
        static void Main(string[] args)
        {
            int max = 1000000000;
            Stopwatch stopWatch = new Stopwatch();

            if (args.Length == 1 && args[0].ToString() == "While")
            {
                Console.WriteLine("While Loop: ");
                stopWatch.Start();
                WhileLoop(max);
                stopWatch.Stop();
                DisplayElapsedTime(stopWatch.Elapsed);
            }
            else
            {
                Console.WriteLine("For Loop: ");
                stopWatch.Start();
                ForLoop(max);
                stopWatch.Stop();
                DisplayElapsedTime(stopWatch.Elapsed);
            }
        }

        private static void WhileLoop(int max)
        {
            int i = 0;
            while (i <= max)
            {
                //Console.WriteLine(i);
                i++;
            };
        }

        private static void ForLoop(int max)
        {
            for (int i = 0; i <= max; i++)
            {
                //Console.WriteLine(i);
            }
        }

        private static void DisplayElapsedTime(TimeSpan ts)
        {
            // Format and display the TimeSpan value.
            string elapsedTime = String.Format("{0:00}:{1:00}:{2:00}.{3:00}",
                ts.Hours, ts.Minutes, ts.Seconds,
                ts.Milliseconds / 10);
            Console.WriteLine(elapsedTime, "RunTime");
        }
    }

When to use the !important property in CSS

!important is somewhat like eval. It isn't a good solution to any problem, and there are very few problems that can't be solved without it.

Regex lookahead, lookbehind and atomic groups

Grokking lookaround rapidly.
How to distinguish lookahead and lookbehind? Take 2 minutes tour with me:

(?=) - positive lookahead
(?<=) - positive lookbehind

Suppose

    A  B  C #in a line

Now, we ask B, Where are you?
B has two solutions to declare it location:

One, B has A ahead and has C bebind
Two, B is ahead(lookahead) of C and behind (lookhehind) A.

As we can see, the behind and ahead are opposite in the two solutions.
Regex is solution Two.

How to close existing connections to a DB

in restore wizard click "close existing connections to destination database"

in Detach Database wizard click "Drop connection" item.

Best practices to test protected methods with PHPUnit

I'm going to throw my hat into the ring here:

I've used the __call hack with mixed degrees of success. The alternative I came up with was to use the Visitor pattern:

1: generate a stdClass or custom class (to enforce type)

2: prime that with the required method and arguments

3: ensure that your SUT has an acceptVisitor method which will execute the method with the arguments specified in the visiting class

4: inject it into the class you wish to test

5: SUT injects the result of operation into the visitor

6: apply your test conditions to the Visitor's result attribute

How to convert JSON to CSV format and store in a variable

Personally I would use d3-dsv library to do this. Why to reinvent the wheel?


import { csvFormat } from 'd3-dsv';
/**
 * Based on input data convert it to csv formatted string
 * @param (Array) columnsToBeIncluded array of column names (strings)
 *                which needs to be included in the formated csv
 * @param {Array} input array of object which need to be transformed to string
 */
export function convertDataToCSVFormatString(input, columnsToBeIncluded = []) {
  if (columnsToBeIncluded.length === 0) {
    return csvFormat(input);
  }
  return csvFormat(input, columnsToBeIncluded);
}

With tree-shaking you can just import that particular function from d3-dsv library

How can I join multiple SQL tables using the IDs?

You have not joined TableD, merely selected the TableD FIELD (dID) from one of the tables.

The application has stopped unexpectedly: How to Debug?

I'm an Eclipse/Android beginner as well, but hopefully my simple debugging process can help...

You set breakpoints in Eclipse by right-clicking next to the line you want to break at and selecting "Toggle Breakpoint". From there you'll want to select "Debug" rather than the standard "Run", which will allow you to step through and so on. Use the filters provided by LogCat (referenced in your tutorial) so you can target the messages you want rather than wading through all the output. That will (hopefully) go a long way in helping you make sense of your errors.

As for other good tutorials, I was searching around for a few myself, but didn't manage to find any gems yet.