Programs & Examples On #Httppostedfile

Better solution without exluding fields from Binding

You should not use your domain models in your views. ViewModels are the correct way to do it.

You need to map your domain model's necessary fields to viewmodel and then use this viewmodel in your controllers. This way you will have the necessery abstraction in your application.

If you never heard of viewmodels, take a look at this.

How to set up a Web API controller for multipart/form-data

Perhaps it is late for the party. But there is an alternative solution for this is to use ApiMultipartFormFormatter plugin.

This plugin helps you to receive the multipart/formdata content as ASP.NET Core does.

In the github page, demo is already provided.

ASP.Net MVC - Read File from HttpPostedFileBase without save

A slight change to Thangamani Palanisamy answer, which allows the Binary reader to be disposed and corrects the input length issue in his comments.

string result = string.Empty;

using (BinaryReader b = new BinaryReader(file.InputStream))
{
  byte[] binData = b.ReadBytes(file.ContentLength);
  result = System.Text.Encoding.UTF8.GetString(binData);
}

MVC 4 Razor File Upload

you just have to change the name of your input filed because same name is required in parameter and input field name just replace this line Your code working fine

 <input type="file" name="file" />

How To Accept a File POST

Here is a quick and dirty solution which takes uploaded file contents from the HTTP body and writes it to a file. I included a "bare bones" HTML/JS snippet for the file upload.

Web API Method:

[Route("api/myfileupload")]        
[HttpPost]
public string MyFileUpload()
{
    var request = HttpContext.Current.Request;
    var filePath = "C:\\temp\\" + request.Headers["filename"];
    using (var fs = new System.IO.FileStream(filePath, System.IO.FileMode.Create))
    {
        request.InputStream.CopyTo(fs);
    }
    return "uploaded";
}

HTML File Upload:

<form>
    <input type="file" id="myfile"/>  
    <input type="button" onclick="uploadFile();" value="Upload" />
</form>
<script type="text/javascript">
    function uploadFile() {        
        var xhr = new XMLHttpRequest();                 
        var file = document.getElementById('myfile').files[0];
        xhr.open("POST", "api/myfileupload");
        xhr.setRequestHeader("filename", file.name);
        xhr.send(file);
    }
</script>

Convert HttpPostedFileBase to byte[]

As Darin says, you can read from the input stream - but I'd avoid relying on all the data being available in a single go. If you're using .NET 4 this is simple:

MemoryStream target = new MemoryStream();
model.File.InputStream.CopyTo(target);
byte[] data = target.ToArray();

It's easy enough to write the equivalent of CopyTo in .NET 3.5 if you want. The important part is that you read from HttpPostedFileBase.InputStream.

For efficient purposes you could check whether the stream returned is already a MemoryStream:

byte[] data;
using (Stream inputStream = model.File.InputStream)
{
    MemoryStream memoryStream = inputStream as MemoryStream;
    if (memoryStream == null)
    {
        memoryStream = new MemoryStream();
        inputStream.CopyTo(memoryStream);
    }
    data = memoryStream.ToArray();
}

MVC 3 file upload and model binding

If you won't always have images posting to your action, you can do something like this:

[HttpPost]
public ActionResult Uploadfile(Container container, HttpPostedFileBase file) 
{
    //do container stuff

    if (Request.Files != null)
    {
        foreach (string requestFile in Request.Files)
        {
            HttpPostedFileBase file = Request.Files[requestFile]; 
            if (file.ContentLength > 0)
            {
                string fileName = Path.GetFileName(file.FileName);
                string directory = Server.MapPath("~/App_Data/uploads/");
                if (!Directory.Exists(directory))
                {
                    Directory.CreateDirectory(directory);
                }
                string path = Path.Combine(directory, fileName);
                file.SaveAs(path);
            }
        }
    }

} 

How to create byte array from HttpPostedFile

in your question, both buffer and byteArray seem to be byte[]. So:

ImageElement image = ImageElement.FromBinary(buffer);

Are these methods thread safe?

It follows the convention that static methods should be thread-safe, but actually in v2 that static api is a proxy to an instance method on a default instance: in the case protobuf-net, it internally minimises contention points, and synchronises the internal state when necessary. Basically the library goes out of its way to do things right so that you can have simple code.

How to add a custom Ribbon tab using VBA?

I was able to accomplish this with VBA in Excel 2013. No special editors needed. All you need is the Visual Basic code editor which can be accessed on the Developer tab. The Developer tab is not visible by default so it needs to be enabled in File>Options>Customize Ribbon. On the Developer tab, click the Visual Basic button. The code editor will launch. Right click in the Project Explorer pane on the left. Click the insert menu and choose module. Add both subs below to the new module.

Sub LoadCustRibbon()

Dim hFile As Long
Dim path As String, fileName As String, ribbonXML As String, user As String

hFile = FreeFile
user = Environ("Username")
path = "C:\Users\" & user & "\AppData\Local\Microsoft\Office\"
fileName = "Excel.officeUI"

ribbonXML = "<mso:customUI      xmlns:mso='http://schemas.microsoft.com/office/2009/07/customui'>" & vbNewLine
ribbonXML = ribbonXML + "  <mso:ribbon>" & vbNewLine
ribbonXML = ribbonXML + "    <mso:qat/>" & vbNewLine
ribbonXML = ribbonXML + "    <mso:tabs>" & vbNewLine
ribbonXML = ribbonXML + "      <mso:tab id='reportTab' label='Reports' insertBeforeQ='mso:TabFormat'>" & vbNewLine
ribbonXML = ribbonXML + "        <mso:group id='reportGroup' label='Reports' autoScale='true'>" & vbNewLine
ribbonXML = ribbonXML + "          <mso:button id='runReport' label='PTO' "   & vbNewLine
ribbonXML = ribbonXML + "imageMso='AppointmentColor3'      onAction='GenReport'/>" & vbNewLine
ribbonXML = ribbonXML + "        </mso:group>" & vbNewLine
ribbonXML = ribbonXML + "      </mso:tab>" & vbNewLine
ribbonXML = ribbonXML + "    </mso:tabs>" & vbNewLine
ribbonXML = ribbonXML + "  </mso:ribbon>" & vbNewLine
ribbonXML = ribbonXML + "</mso:customUI>"

ribbonXML = Replace(ribbonXML, """", "")

Open path & fileName For Output Access Write As hFile
Print #hFile, ribbonXML
Close hFile

End Sub

Sub ClearCustRibbon()

Dim hFile As Long
Dim path As String, fileName As String, ribbonXML As String, user As String

hFile = FreeFile
user = Environ("Username")
path = "C:\Users\" & user & "\AppData\Local\Microsoft\Office\"
fileName = "Excel.officeUI"

ribbonXML = "<mso:customUI           xmlns:mso=""http://schemas.microsoft.com/office/2009/07/customui"">" & _
"<mso:ribbon></mso:ribbon></mso:customUI>"

Open path & fileName For Output Access Write As hFile
Print #hFile, ribbonXML
Close hFile

End Sub

Call LoadCustRibbon sub in the Wookbook open even and call the ClearCustRibbon sub in the Before_Close Event of the ThisWorkbook code file.

Get Selected value from Multi-Value Select Boxes by jquery-select2?

I know its late but I think you can try like this

$("#multipledpdwn").on("select2:select select2:unselect", function (e) {

    //this returns all the selected item
    var items= $(this).val();       

    //Gets the last selected item
    var lastSelectedItem = e.params.data.id;

})

Hope it may help some one in future.

Click in OK button inside an Alert (Selenium IDE)

This is an answer from 2012, the question if from 2009, but people still look at it and there's only one correct (use WebDriver) and one almost useful (but not good enough) answer.


If you're using Selenium RC and can actually see an alert dialog, then it can't be done. Selenium should handle it for you. But, as stated in Selenium documentation:

Selenium tries to conceal those dialogs from you (by replacing window.alert, window.confirm and window.prompt) so they won’t stop the execution of your page. If you’re seeing an alert pop-up, it’s probably because it fired during the page load process, which is usually too early for us to protect the page.

It is a known limitation of Selenium RC (and, therefore, Selenium IDE, too) and one of the reasons why Selenium 2 (WebDriver) was developed. If you want to handle onload JS alerts, you need to use WebDriver alert handling.

That said, you can use Robot or selenium.keyPressNative() to fill in any text and press Enter and confirm the dialog blindly. It's not the cleanest way, but it could work. You won't be able to get the alert message, however.

Robot has all the useful keys mapped to constants, so that will be easy. With keyPressNative(), you want to use 10 as value for pressing Enter or 27 for Esc since it works with ASCII codes.

Check if string has space in between (or anywhere)

If indeed the goal is to see if a string contains the actual space character (as described in the title), as opposed to any other sort of whitespace characters, you can use:

string s = "Hello There";
bool fHasSpace = s.Contains(" ");

If you're looking for ways to detect whitespace, there's several great options below.

Delete all records in a table of MYSQL in phpMyAdmin

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

delete from tableName;

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

or

truncate tableName;

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

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

Easiest way to convert int to string in C++

It's rather easy to add some syntactical sugar that allows one to compose strings on the fly in a stream-like way

#include <string>
#include <sstream>

struct strmake {
    std::stringstream s;
    template <typename T> strmake& operator << (const T& x) {
        s << x; return *this;
    }   
    operator std::string() {return s.str();}
};

Now you may append whatever you want (provided that an operator << (std::ostream& ..) is defined for it) to strmake() and use it in place of an std::string.

Example:

#include <iostream>

int main() {
    std::string x =
      strmake() << "Current time is " << 5+5 << ":" << 5*5 << " GST";
    std::cout << x << std::endl;
}

Subversion stuck due to "previous operation has not finished"?

I had the same problem, and somehow found that I had a hidden .svn file at the c:\ level. Once I deleted this hidden folder (.svn), everything worked okay. I must have unintentionally created a working directory at the root drive.

CardView Corner Radius

NOTE: This here is a workaround if you want to achieve rounded corners at the bottom only and regular corners at the top. This will not work if you want to have different radius for all four corners of the cardview. You will have to use material cardview for it or use some third party library.

Here's what seemed to work for me:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:background="#F9F9F9">

    <androidx.cardview.widget.CardView
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="200dp"
            android:background="@drawable/profile_bg"/>

    </androidx.cardview.widget.CardView>

    <androidx.cardview.widget.CardView
        android:id="@+id/cvProfileHeader"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:cardCornerRadius="32dp">
    
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="280dp"
            android:orientation="vertical"
            android:background="@drawable/profile_bg"
            android:id="@+id/llProfileHeader"
            android:gravity="center_horizontal">

            <!--Enter your code here-->

        </LinearLayout>
    
    </androidx.cardview.widget.CardView>

</RelativeLayout>

There's two cardview's in all. The second cardview is the one that will have rounded corners (on all sides as usual) and will hold all other subviews under it. The first cardview above it is also at the same level (of elevation), and has the same background but is only about half the height of the second cardview and has no rounded corners (just the usual sharp corners). This way I was able to achieve partially rounded corners on the bottom and normal corners on the top. But for all four sides, you may have to use the material cardview.

You could do the reverse of this to get rounded corners at the top and regular ones at the bottom, i.e. let the first cardview have rounded corners and the second cardview have regular corners.

Making an svg image object clickable with onclick, avoiding absolute positioning

If you just use inline svg there is no problem.

_x000D_
_x000D_
<svg id="svg1" xmlns="http://www.w3.org/2000/svg" style="width: 3.5in; height: 1in">_x000D_
  <circle id="circle1" r="30" cx="34" cy="34" onclick="circle1.style.fill='yellow';"_x000D_
            style="fill: red; stroke: blue; stroke-width: 2"/>_x000D_
  </svg>_x000D_
  
_x000D_
_x000D_
_x000D_

How to send HTML-formatted email?

This works for me

msg.BodyFormat = MailFormat.Html;

and then you can use html in your body

msg.Body = "<em>It's great to use HTML in mail!!</em>"

OnChange event handler for radio button (INPUT type="radio") doesn't work as one value

<input type="radio" name="brd" onclick="javascript:brd();" value="IN">   
<input type="radio" name="brd" onclick="javascript:brd();" value="EX">` 
<script type="text/javascript">
  function brd() {alert($('[name="brd"]:checked').val());}
</script>

What are advantages of Artificial Neural Networks over Support Vector Machines?

One obvious advantage of artificial neural networks over support vector machines is that artificial neural networks may have any number of outputs, while support vector machines have only one. The most direct way to create an n-ary classifier with support vector machines is to create n support vector machines and train each of them one by one. On the other hand, an n-ary classifier with neural networks can be trained in one go. Additionally, the neural network will make more sense because it is one whole, whereas the support vector machines are isolated systems. This is especially useful if the outputs are inter-related.

For example, if the goal was to classify hand-written digits, ten support vector machines would do. Each support vector machine would recognize exactly one digit, and fail to recognize all others. Since each handwritten digit cannot be meant to hold more information than just its class, it makes no sense to try to solve this with an artificial neural network.

However, suppose the goal was to model a person's hormone balance (for several hormones) as a function of easily measured physiological factors such as time since last meal, heart rate, etc ... Since these factors are all inter-related, artificial neural network regression makes more sense than support vector machine regression.

Create a list from two object lists with linq

This can easily be done by using the Linq extension method Union. For example:

var mergedList = list1.Union(list2).ToList();

This will return a List in which the two lists are merged and doubles are removed. If you don't specify a comparer in the Union extension method like in my example, it will use the default Equals and GetHashCode methods in your Person class. If you for example want to compare persons by comparing their Name property, you must override these methods to perform the comparison yourself. Check the following code sample to accomplish that. You must add this code to your Person class.

/// <summary>
/// Checks if the provided object is equal to the current Person
/// </summary>
/// <param name="obj">Object to compare to the current Person</param>
/// <returns>True if equal, false if not</returns>
public override bool Equals(object obj)
{        
    // Try to cast the object to compare to to be a Person
    var person = obj as Person;

    return Equals(person);
}

/// <summary>
/// Returns an identifier for this instance
/// </summary>
public override int GetHashCode()
{
    return Name.GetHashCode();
}

/// <summary>
/// Checks if the provided Person is equal to the current Person
/// </summary>
/// <param name="personToCompareTo">Person to compare to the current person</param>
/// <returns>True if equal, false if not</returns>
public bool Equals(Person personToCompareTo)
{
    // Check if person is being compared to a non person. In that case always return false.
    if (personToCompareTo == null) return false;

    // If the person to compare to does not have a Name assigned yet, we can't define if it's the same. Return false.
    if (string.IsNullOrEmpty(personToCompareTo.Name) return false;

    // Check if both person objects contain the same Name. In that case they're assumed equal.
    return Name.Equals(personToCompareTo.Name);
}

If you don't want to set the default Equals method of your Person class to always use the Name to compare two objects, you can also write a comparer class which uses the IEqualityComparer interface. You can then provide this comparer as the second parameter in the Linq extension Union method. More information on how to write such a comparer method can be found on http://msdn.microsoft.com/en-us/library/system.collections.iequalitycomparer.aspx

remove table row with specific id

As bellow we can remove table rows with specific row id

<html>
<head>
    <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3.2/jquery.js" type="text/javascript"></script>
<script type="text/javascript">
function remove(id)
{
$('table#test tr#'+id).remove();
// or you can use bellow line also
//$('#test tr#'+id).remove();
}
</script>
    </head>
<body>
<table id="test">
 <tr id="1"><td>bla</td><td><input type="button" onclick="remove(1)"value="Remove"></td></tr>
 <tr id="2"><td>bla</td><td><input type="button" onclick="remove(2)" value="Remove"></td></tr>
 <tr id="3"><td>bla</td><td><input type="button" onclick="remove(3)" value="Remove"></td></tr>
 <tr id="4"><td>bla</td><td><input type="button" onclick="remove(4)" value="Remove"></td></tr>
</table>
</body></html>

How to check if Thread finished execution

For a thread you have the myThread.IsAlive property. It is false if the thread method returned or the thread was aborted.

Visually managing MongoDB documents and collections

If you're able to run PHP scripts you can give PHP MongoDB Admin a try. It's a single PHP script that gives you basic management and searching functionality.

Open file dialog and select a file using WPF controls and C#

var ofd = new Microsoft.Win32.OpenFileDialog() {Filter = "JPEG Files (*.jpeg)|*.jpeg|PNG Files (*.png)|*.png|JPG Files (*.jpg)|*.jpg|GIF Files (*.gif)|*.gif"}; 
var result = ofd.ShowDialog();
if (result == false) return;
textBox1.Text = ofd.FileName;

How is Perl's @INC constructed? (aka What are all the ways of affecting where Perl modules are searched for?)

As it was said already @INC is an array and you're free to add anything you want.

My CGI REST script looks like:

#!/usr/bin/perl
use strict;
use warnings;
BEGIN {
    push @INC, 'fully_qualified_path_to_module_wiht_our_REST.pm';
}
use Modules::Rest;
gone(@_);

Subroutine gone is exported by Rest.pm.

What is the best alternative IDE to Visual Studio

There's MonoDevelop, which I occasionally use when I want to do some light C# coding when in Linux. It's nothing close to VS.Net, but it works for small projects. I really don't think most of the alternatives people have listed come anywhere close to VS.Net.

Getting coordinates of marker in Google Maps API

One more alternative options

var map = new google.maps.Map(document.getElementById('map_canvas'), {
    zoom: 1,
    center: new google.maps.LatLng(35.137879, -82.836914),
    mapTypeId: google.maps.MapTypeId.ROADMAP
});

var myMarker = new google.maps.Marker({
    position: new google.maps.LatLng(47.651968, 9.478485),
    draggable: true
});

google.maps.event.addListener(myMarker, 'dragend', function (evt) {
    document.getElementById('current').innerHTML = '<p>Marker dropped: Current Lat: ' + evt.latLng.lat().toFixed(3) + ' Current Lng: ' + evt.latLng.lng().toFixed(3) + '</p>';
});

google.maps.event.addListener(myMarker, 'dragstart', function (evt) {
    document.getElementById('current').innerHTML = '<p>Currently dragging marker...</p>';
});

map.setCenter(myMarker.position);
myMarker.setMap(map);

and html file

<body>
    <section>
        <div id='map_canvas'></div>
        <div id="current">Nothing yet...</div>
    </section>
</body>

Remove all git files from a directory?

In case someone else stumbles onto this topic - here's a more "one size fits all" solution.

If you are using .git or .svn, you can use the --exclude-vcs option for tar. This will ignore many different files/folders required by different version control systems.

If you want to read more about it, check out: http://www.gnu.org/software/tar/manual/html_section/exclude.html

String concatenation in MySQL

Use concat() function instead of + like this:

select concat(firstname, lastname) as "Name" from test.student

How to set focus on an input field after rendering?

Focus on mount

If you just want to focus an element when it mounts (initially renders) a simple use of the autoFocus attribute will do.

<input type="text" autoFocus />

Dynamic focus

to control focus dynamically use a general function to hide implementation details from your components.

React 16.8 + Functional component - useFocus hook

const FocusDemo = () => {

    const [inputRef, setInputFocus] = useFocus()

    return (
        <> 
            <button onClick={setInputFocus} >
               FOCUS
            </button>
            <input ref={inputRef} />
        </>
    )
    
}

const useFocus = () => {
    const htmlElRef = useRef(null)
    const setFocus = () => {htmlElRef.current &&  htmlElRef.current.focus()}

    return [ htmlElRef, setFocus ] 
}

Full Demo

React 16.3 + Class Components - utilizeFocus

class App extends Component {
  constructor(props){
    super(props)
    this.inputFocus = utilizeFocus()
  }

  render(){
    return (
      <> 
          <button onClick={this.inputFocus.setFocus}>
             FOCUS
          </button>
          <input ref={this.inputFocus.ref}/>
      </>
    )
  } 
}
const utilizeFocus = () => {
    const ref = React.createRef()
    const setFocus = () => {ref.current &&  ref.current.focus()}

    return {setFocus, ref} 
}

Full Demo

How do you embed binary data in XML?

I had this problem just last week. I had to serialize a PDF file and send it, inside an XML file, to a server.

If you're using .NET, you can convert a binary file directly to a base64 string and stick it inside an XML element.

string base64 = Convert.ToBase64String(File.ReadAllBytes(fileName));

Or, there is a method built right into the XmlWriter object. In my particular case, I had to include Microsoft's datatype namespace:

StringBuilder sb = new StringBuilder();
System.Xml.XmlWriter xw = XmlWriter.Create(sb);
xw.WriteStartElement("doc");
xw.WriteStartElement("serialized_binary");
xw.WriteAttributeString("types", "dt", "urn:schemas-microsoft-com:datatypes", "bin.base64");
byte[] b = File.ReadAllBytes(fileName);
xw.WriteBase64(b, 0, b.Length);
xw.WriteEndElement();
xw.WriteEndElement();
string abc = sb.ToString();

The string abc looks something that looks like this:

<?xml version="1.0" encoding="utf-16"?>
<doc>
    <serialized_binary types:dt="bin.base64" xmlns:types="urn:schemas-microsoft-com:datatypes">
        JVBERi0xLjMKJaqrrK0KNCAwIG9iago8PCAvVHlwZSAvSW5mbw...(plus lots more)
    </serialized_binary>
</doc>

Cannot call getSupportFragmentManager() from activity

This worked for me. Running android API 19 and above.

FragmentManager fragMan = getFragmentManager();

How to get form input array into PHP array

Nonetheless, you can use below code as,

$a = array('name1','name2','name3');
$b = array('email1','email2','email3');

function f($a,$b){
    return "The name is $a and email is $b, thank you";
}

$c = array_map('f', $a, $b);

//echoing the result

foreach ($c as $val) {
    echo $val.'<br>';
}

How do I force my .NET application to run as administrator?

You can embed a manifest file in the EXE file, which will cause Windows (7 or higher) to always run the program as an administrator.

You can find more details in Step 6: Create and Embed an Application Manifest (UAC) (MSDN).

How to use "svn export" command to get a single file from the repository?

You don't have to do this locally either. You can do it through a remote repository, for example:

svn export http://<repo>/process/test.txt /path/to/code/

Selecting default item from Combobox C#

This means that your selectedindex is out of the range of the array of items in the combobox. The array of items in your combo box is zero-based, so if you have 2 items, it's item 0 and item 1.

How to import an existing X.509 certificate and private key in Java keystore to use in SSL?

If you have a PEM file (e.g. server.pem) containing:

  • the trusted certificate
  • the private key

then you can import the certificate and key into a JKS keystore like this:

1) Copy the private key from the PEM file into an ascii file (e.g. server.key)

2) Copy the cert from the PEM file into an ascii file (e.g. server.crt)

3) Export the cert and key into a PKCS12 file:

$ openssl pkcs12 -export -in server.crt -inkey server.key \
                 -out server.p12 -name [some-alias] -CAfile server.pem -caname root
  • the PEM file can be used as the argument to the -CAfile option.
  • you are prompted for an 'export' password.
  • if doing this in git bash then add winpty to the start of the command so the export password can be entered.

4) Convert the PKCS12 file to a JKS keystore:

$ keytool -importkeystore -deststorepass changeit -destkeypass changeit \
          -destkeystore keystore.jks  -srckeystore server.p12 -srcstoretype PKCS12 \
          -srcstorepass changeit
  • the srcstorepass password should match the export password from step 3)

How to add local .jar file dependency to build.gradle file?

The accepted answer is good, however, I would have needed various library configurations within my multi-project Gradle build to use the same 3rd-party Java library.

Adding '$rootProject.projectDir' to the 'dir' path element within my 'allprojects' closure meant each sub-project referenced the same 'libs' directory, and not a version local to that sub-project:

//gradle.build snippet
allprojects {
    ...

    repositories {
        //All sub-projects will now refer to the same 'libs' directory
        flatDir {
            dirs "$rootProject.projectDir/libs"
        }
        mavenCentral()
    }

    ...
}

EDIT by Quizzie: changed "${rootProject.projectDir}" to "$rootProject.projectDir" (works in the newest Gradle version).

Count cells that contain any text

You can pass "<>" (including the quotes) as the parameter for criteria. This basically says, as long as its not empty/blank, count it. I believe this is what you want.

=COUNTIF(A1:A10, "<>") 

Otherwise you can use CountA as Scott suggests

What is log4j's default log file dumping path

You have copy this sample code from Here,right?
now, as you can see there property file they have define, have you done same thing? if not then add below code in your project with property file for log4j

So the content of log4j.properties file would be as follows:

# Define the root logger with appender file
log = /usr/home/log4j
log4j.rootLogger = DEBUG, FILE

# Define the file appender
log4j.appender.FILE=org.apache.log4j.FileAppender
log4j.appender.FILE.File=${log}/log.out

# Define the layout for file appender
log4j.appender.FILE.layout=org.apache.log4j.PatternLayout
log4j.appender.FILE.layout.conversionPattern=%m%n

make changes as per your requirement like log path

How to make an AJAX call without jQuery?

HTML :

<!DOCTYPE html>
    <html>
    <head>
    <script>
    function loadXMLDoc()
    {
    var xmlhttp;
    if (window.XMLHttpRequest)
      {// code for IE7+, Firefox, Chrome, Opera, Safari
      xmlhttp=new XMLHttpRequest();
      }
    else
      {// code for IE6, IE5
      xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
      }
    xmlhttp.onreadystatechange=function()
      {
      if (xmlhttp.readyState==4 && xmlhttp.status==200)
        {
        document.getElementById("myDiv").innerHTML=xmlhttp.responseText;
        }
      }
    xmlhttp.open("GET","1.php?id=99freebies.blogspot.com",true);
    xmlhttp.send();
    }
    </script>
    </head>
    <body>

    <div id="myDiv"><h2>Let AJAX change this text</h2></div>
    <button type="button" onclick="loadXMLDoc()">Change Content</button>

    </body>
    </html>

PHP:

<?php

$id = $_GET[id];
print "$id";

?>

How to check for file existence

# file? will only return true for files
File.file?(filename)

and

# Will also return true for directories - watch out!
File.exist?(filename)

Python PDF library

The two that come to mind are:

JPA OneToMany and ManyToOne throw: Repeated column in mapping for entity column (should be mapped with insert="false" update="false")

I am not really sure about your question (the meaning of "empty table" etc, or how mappedBy and JoinColumn were not working).

I think you were trying to do a bi-directional relationships.

First, you need to decide which side "owns" the relationship. Hibernate is going to setup the relationship base on that side. For example, assume I make the Post side own the relationship (I am simplifying your example, just to keep things in point), the mapping will look like:

(Wish the syntax is correct. I am writing them just by memory. However the idea should be fine)

public class User{
    @OneToMany(fetch=FetchType.LAZY, cascade = CascadeType.ALL, mappedBy="user")
    private List<Post> posts;
}


public class Post {
    @ManyToOne(fetch=FetchType.LAZY)
    @JoinColumn(name="user_id")
    private User user;
}

By doing so, the table for Post will have a column user_id which store the relationship. Hibernate is getting the relationship by the user in Post (Instead of posts in User. You will notice the difference if you have Post's user but missing User's posts).

You have mentioned mappedBy and JoinColumn is not working. However, I believe this is in fact the correct way. Please tell if this approach is not working for you, and give us a bit more info on the problem. I believe the problem is due to something else.


Edit:

Just a bit extra information on the use of mappedBy as it is usually confusing at first. In mappedBy, we put the "property name" in the opposite side of the bidirectional relationship, not table column name.

C# create simple xml file

You could use XDocument:

new XDocument(
    new XElement("root", 
        new XElement("someNode", "someValue")    
    )
)
.Save("foo.xml");

If the file you want to create is very big and cannot fit into memory you might use XmlWriter.

HTTPS setup in Amazon EC2

Use Elastic Load Balacing, it supports SSL termination at the Load Balancer, including offloading SSL decryption from application instances and providing centralized management of SSL certificates.

How do I execute multiple SQL Statements in Access' Query Editor?

"I hoped (and still hope) that there is something like my beloved SQL*Plus for Oracle that can execute a file with all kinds of SQL Statements."

If you're looking for a simple program that can import a file and execute the SQL statements in it, take a look at DBWConsole (freeware). I have used it to process DDL scripts (table schema) as well as action queries. It does not return data sets so it's not useful for SELECT queries. It supports single line comments prefixed by -- but not multi-line comments wrapped in /* */. It supports command line parameters.

enter image description here

If you want an interactive UI like Oracle SQL Developer or SSMS for Access then Matthew Lock's reference to WinSQL is what you should try.

How to do SQL Like % in Linq?

I'm assuming you're using Linq-to-SQL* (see note below). If so, use string.Contains, string.StartsWith, and string.EndsWith to generate SQL that use the SQL LIKE operator.

from o in dc.Organization
join oh in dc.OrganizationsHierarchy on o.Id equals oh.OrganizationsId
where oh.Hierarchy.Contains(@"/12/")
select new { o.Id, o.Name }

or

from o in dc.Organization
where o.OrganizationsHierarchy.Hierarchy.Contains(@"/12/")
select new { o.Id, o.Name }

Note: * = if you are using the ADO.Net Entity Framework (EF / L2E) in .net 3.5, be aware that it will not do the same translation as Linq-to-SQL. Although L2S does a proper translation, L2E v1 (3.5) will translate into a t-sql expression that will force a full table scan on the table you're querying unless there is another better discriminator in your where clause or join filters.
Update: This is fixed in EF/L2E v4 (.net 4.0), so it will generate a SQL LIKE just like L2S does.

Remove multiple items from a Python list in just one statement

You Can use this -

Suppose we have a list, l = [1,2,3,4,5]

We want to delete last two items in a single statement

del l[3:]

We have output:

l = [1,2,3]

Keep it Simple

How to present popover properly in iOS 8

Actually it is much simpler than that. In the storyboard you should make the viewcontroller you want to use as popover and make a viewcontroller class for it as usual. Make a segue as shown below from the object you want to open the popover, in this case the UIBarButton named "Config".

enter image description here

In the "mother viewcontroller" implement the UIPopoverPresentationControllerDelegate and the delegate method:

func popoverPresentationControllerDidDismissPopover(popoverPresentationController: UIPopoverPresentationController) {
    //do som stuff from the popover
}

Override the prepareForSeque method like this:

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
     //segue for the popover configuration window
    if segue.identifier == "yourSegueIdentifierForPopOver" {
        if let controller = segue.destinationViewController as? UIViewController {
            controller.popoverPresentationController!.delegate = self
            controller.preferredContentSize = CGSize(width: 320, height: 186)
        }
    }
}

And you're done. And you can now treat the popover view as any other view, ie. add fields and what not! And you get hold of the the content controller by using the popoverPresentationController.presentedViewController method in the UIPopoverPresentationController.

Also on an iPhone you would have to overwrite

func adaptivePresentationStyle(for controller: UIPresentationController) -> UIModalPresentationStyle {

        return UIModalPresentationStyle.none
    } 

How to replace negative numbers in Pandas Data Frame by zero

If all your columns are numeric, you can use boolean indexing:

In [1]: import pandas as pd

In [2]: df = pd.DataFrame({'a': [0, -1, 2], 'b': [-3, 2, 1]})

In [3]: df
Out[3]: 
   a  b
0  0 -3
1 -1  2
2  2  1

In [4]: df[df < 0] = 0

In [5]: df
Out[5]: 
   a  b
0  0  0
1  0  2
2  2  1

For the more general case, this answer shows the private method _get_numeric_data:

In [1]: import pandas as pd

In [2]: df = pd.DataFrame({'a': [0, -1, 2], 'b': [-3, 2, 1],
                           'c': ['foo', 'goo', 'bar']})

In [3]: df
Out[3]: 
   a  b    c
0  0 -3  foo
1 -1  2  goo
2  2  1  bar

In [4]: num = df._get_numeric_data()

In [5]: num[num < 0] = 0

In [6]: df
Out[6]: 
   a  b    c
0  0  0  foo
1  0  2  goo
2  2  1  bar

With timedelta type, boolean indexing seems to work on separate columns, but not on the whole dataframe. So you can do:

In [1]: import pandas as pd

In [2]: df = pd.DataFrame({'a': pd.to_timedelta([0, -1, 2], 'd'),
   ...:                    'b': pd.to_timedelta([-3, 2, 1], 'd')})

In [3]: df
Out[3]: 
        a       b
0  0 days -3 days
1 -1 days  2 days
2  2 days  1 days

In [4]: for k, v in df.iteritems():
   ...:     v[v < 0] = 0
   ...:     

In [5]: df
Out[5]: 
       a      b
0 0 days 0 days
1 0 days 2 days
2 2 days 1 days

Update: comparison with a pd.Timedelta works on the whole DataFrame:

In [1]: import pandas as pd

In [2]: df = pd.DataFrame({'a': pd.to_timedelta([0, -1, 2], 'd'),
   ...:                    'b': pd.to_timedelta([-3, 2, 1], 'd')})

In [3]: df[df < pd.Timedelta(0)] = 0

In [4]: df
Out[4]: 
       a      b
0 0 days 0 days
1 0 days 2 days
2 2 days 1 days

ASP.NET Web API : Correct way to return a 401/unauthorised response

As an alternative to the other answers, you can also use this code if you want to return an IActionResult within an ASP.NET controller.

ASP.NET

 return Content(HttpStatusCode.Unauthorized, "My error message");

Update: ASP.NET Core

Above code does not work in ASP.NET Core, you can use one of these instead:

 return StatusCode((int)System.Net.HttpStatusCode.Unauthorized, "My error message");
 return StatusCode(Microsoft.AspNetCore.Http.StatusCodes.Status401Unauthorized, "My error message");
 return StatusCode(401, "My error message");

Apparently the reason phrase is pretty optional (Can an HTTP response omit the Reason-Phrase?)

Difference between text and varchar (character varying)

Somewhat OT: If you're using Rails, the standard formatting of webpages may be different. For data entry forms text boxes are scrollable, but character varying (Rails string) boxes are one-line. Show views are as long as needed.

Add column to SQL Server

Of course! Just use the ALTER TABLE... syntax.

Example

ALTER TABLE YourTable
  ADD Foo INT NULL /*Adds a new int column existing rows will be 
                     given a NULL value for the new column*/

Or

ALTER TABLE YourTable
  ADD Bar INT NOT NULL DEFAULT(0) /*Adds a new int column existing rows will
                                    be given the value zero*/

In SQL Server 2008 the first one is a metadata only change. The second will update all rows.

In SQL Server 2012+ Enterprise edition the second one is a metadata only change too.

Can you disable tabs in Bootstrap?

As of 2.1, from bootstrap documentation at http://twitter.github.com/bootstrap/components.html#navs, you can.

Disabled state

For any nav component (tabs, pills, or list), add .disabled for gray links and no hover effects. Links will remain clickable, however, unless you remove the href attribute. Alternatively, you could implement custom JavaScript to prevent those clicks.

See https://github.com/twitter/bootstrap/issues/2764 for the feature add discussion.

Check if a string contains a number

You can use NLTK method for it.

This will find both '1' and 'One' in the text:

import nltk 

def existence_of_numeric_data(text):
    text=nltk.word_tokenize(text)
    pos = nltk.pos_tag(text)
    count = 0
    for i in range(len(pos)):
        word , pos_tag = pos[i]
        if pos_tag == 'CD':
            return True
    return False

existence_of_numeric_data('We are going out. Just five you and me.')

How to use private Github repo as npm dependency

I wasn't able to make the accepted answer work in a Docker container.

What worked for me was to set the Personal Access Token from github in a file .nextrc

ARG GITHUB_READ_TOKEN
RUN echo -e "machine github.com\n  login $GITHUB_READ_TOKEN" > ~/.netrc 
RUN npm install --only=production --force \
  && npm cache clean --force
RUN rm ~/.netrc

in package.json

"my-lib": "github:username/repo",

Removing Data From ElasticSearch

There are lots of good answers here, but there is also something i'd like to add:

  • If you are running on AWS ElasticSearch service, you can´t drop/delete indexes. Instead of delete indexes, you must reindex them.

Warning: date_format() expects parameter 1 to be DateTime

I've tried sean662's 3rd solution and worked with now() function stored in an INSERT sql an then it's value in the date_create() function. After that the variable is then passed through the date_format() function and you can have the date order that you like.

How to count the number of occurrences of a character in an Oracle varchar value?

Here you go:

select length('123-345-566') - length(replace('123-345-566','-',null)) 
from dual;

Technically, if the string you want to check contains only the character you want to count, the above query will return NULL; the following query will give the correct answer in all cases:

select coalesce(length('123-345-566') - length(replace('123-345-566','-',null)), length('123-345-566'), 0) 
from dual;

The final 0 in coalesce catches the case where you're counting in an empty string (i.e. NULL, because length(NULL) = NULL in ORACLE).

How do I configure the proxy settings so that Eclipse can download new plugins?

There is an eclipse.ini (sts.ini) parameter that can help:

-Djava.net.useSystemProxies=true

A lot of effort wasted on this trivial setting each time I change the work environment... See one of the related bugs on eclipse bugzilla.

How do I find the CPU and RAM usage using PowerShell?

You can also use the Get-Counter cmdlet (PowerShell 2.0):

Get-Counter '\Memory\Available MBytes'
Get-Counter '\Processor(_Total)\% Processor Time'

To get a list of memory counters:

Get-Counter -ListSet *memory* | Select-Object -ExpandProperty  Counter

How to get name of calling function/method in PHP?

You can also use the info provided by a php exception, it's an elegant solution:


function GetCallingMethodName(){
    $e = new Exception();
    $trace = $e->getTrace();
    //position 0 would be the line that called this function so we ignore it
    $last_call = $trace[1];
    print_r($last_call);
}

function firstCall($a, $b){
    theCall($a, $b);
}

function theCall($a, $b){
    GetCallingMethodName();
}

firstCall('lucia', 'php');

And you get this... (voilà!)

Array
(
    [file] => /home/lufigueroa/Desktop/test.php
    [line] => 12
    [function] => theCall
    [args] => Array
        (
            [0] => lucia
            [1] => php
        )

)

How to remove an item from an array in Vue.js

It is even funnier when you are doing it with inputs, because they should be bound. If you are interested in how to do it in Vue2 with options to insert and delete, please see an example:

please have a look an js fiddle

_x000D_
_x000D_
new Vue({_x000D_
  el: '#app',_x000D_
  data: {_x000D_
    finds: [] _x000D_
  },_x000D_
  methods: {_x000D_
    addFind: function () {_x000D_
      this.finds.push({ value: 'def' });_x000D_
    },_x000D_
    deleteFind: function (index) {_x000D_
      console.log(index);_x000D_
      console.log(this.finds);_x000D_
      this.finds.splice(index, 1);_x000D_
    }_x000D_
  }_x000D_
});
_x000D_
<script src="https://unpkg.com/[email protected]/dist/vue.js"></script>_x000D_
<div id="app">_x000D_
  <h1>Finds</h1>_x000D_
  <div v-for="(find, index) in finds">_x000D_
    <input v-model="find.value">_x000D_
    <button @click="deleteFind(index)">_x000D_
      delete_x000D_
    </button>_x000D_
  </div>_x000D_
  _x000D_
  <button @click="addFind">_x000D_
    New Find_x000D_
  </button>_x000D_
  _x000D_
  <pre>{{ $data }}</pre>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Git pushing to remote branch

Simply push this branch to a different branch name

 git push -u origin localBranch:remoteBranch

How to allow download of .json file with ASP.NET

Solution is you need to add json file extension type in MIME Types

Method 1

Go to IIS, Select your application and Find MIME Types

enter image description here

Click on Add from Right panel

File Name Extension = .json

MIME Type = application/json

enter image description here

After adding .json file type in MIME Types, Restart IIS and try to access json file


Method 2

Go to web.config of that application and add this lines in it

 <system.webServer>
   <staticContent>
     <mimeMap fileExtension=".json" mimeType="application/json" />
   </staticContent>
 </system.webServer>

Log record changes in SQL server in an audit table

Hey It's very simple see this

@OLD_GUEST_NAME = d.GUEST_NAME from deleted d;

this variable will store your old deleted value and then you can insert it where you want.

for example-

Create trigger testupdate on test for update, delete
  as
declare @tableid varchar(50);
declare @testid varchar(50);
declare @newdata varchar(50);
declare @olddata varchar(50);


select @tableid = count(*)+1 from audit_test
select @testid=d.tableid from inserted d;
select @olddata = d.data from deleted d;
select @newdata = i.data from inserted i;

insert into audit_test (tableid, testid, olddata, newdata) values (@tableid, @testid, @olddata, @newdata)

go

Wordpress plugin install: Could not create directory

I was on XAMPP for linux localhost and this worked for me:

sudo chown -R my-linux-username wp-content

Comparing two strings in C?

For comparing 2 strings, either use the built in function strcmp() using header file string.h

if(strcmp(a,b)==0)
    printf("Entered strings are equal");
else
    printf("Entered strings are not equal");

OR you can write your own function like this:

int string_compare(char str1[], char str2[])
{
    int ctr=0;

    while(str1[ctr]==str2[ctr])
    {
        if(str1[ctr]=='\0'||str2[ctr]=='\0')
            break;
        ctr++;
    }
    if(str1[ctr]=='\0' && str2[ctr]=='\0')
        return 0;
    else
        return -1;
}

Is there a way to get a list of column names in sqlite?

Assuming that you know the table name, and want the names of the data columns you can use the listed code will do it in a simple and elegant way to my taste:

import sqlite3

def get_col_names():
#this works beautifully given that you know the table name
    conn = sqlite3.connect("t.db")
    c = conn.cursor()
    c.execute("select * from tablename")
    return [member[0] for member in c.description]

Delete item from array and shrink array

Arrays are fixed in size, you cannot resize them after creating them. You can remove an existing item by setting it to null:

objects[4] = null;

But you won't be able to delete that entire slot off the array and reduce its size by 1.

If you need a dynamically-sized array, you can use an ArrayList. With it, you can add() and remove() objects, and it will grow and shrink as needed.

How to validate Google reCAPTCHA v3 on server side?

I liked Levit's answer and ended up using it. But I just wanted to point out, just in case, that there is an official Google PHP library for new reCAPTCHA: https://github.com/google/recaptcha

The latest version (right now 1.1.2) supports Composer and contains an example that you can run to see if you have configured everything correctly.

Below you can see part of the example that comes with this official library (with my minor modifications for clarity):

// Make the call to verify the response and also pass the user's IP address
    $resp = $recaptcha->verify($_POST['g-recaptcha-response'], $_SERVER['REMOTE_ADDR']);

    if ($resp->isSuccess()) {
// If the response is a success, that's it!
        ?>
        <h2>Success!</h2>
        <p>That's it. Everything is working. Go integrate this into your real project.</p>
        <p><a href="/">Try again</a></p>
        <?php
    } else {
// If it's not successful, then one or more error codes will be returned.
        ?>
        <h2>Something went wrong</h2>
        <p>The following error was returned: <?php
            foreach ($resp->getErrorCodes() as $code) {
                echo '<tt>' , $code , '</tt> ';
            }
            ?></p>
        <p>Check the error code reference at <tt><a href="https://developers.google.com/recaptcha/docs/verify#error-code-reference">https://developers.google.com/recaptcha/docs/verify#error-code-reference</a></tt>.
        <p><strong>Note:</strong> Error code <tt>missing-input-response</tt> may mean the user just didn't complete the reCAPTCHA.</p>
        <p><a href="/">Try again</a></p>
    <?php
    }

Hope it helps someone.

How to make Excel VBA variables available to multiple macros?

You may consider declaring the variables with moudule level scope. Module-level variable is available to all of the procedures in that module, but it is not available to procedures in other modules

For details on Scope of variables refer this link

Please copy the below code into any module, save the workbook and then run the code.

Here is what code does

  • The sample subroutine sets the folder path & later the file path. Kindly set them accordingly before you run the code.

  • I have added a function IsWorkBookOpen to check if workbook is already then set the workbook variable the workbook name else open the workbook which will be assigned to workbook variable accordingly.

Dim wbA As Workbook
Dim wbB As Workbook

Sub MySubRoutine()
    Dim folderPath As String, fileNm1 As String, fileNm2 As String, filePath1 As String, filePath2 As String

    folderPath = ThisWorkbook.Path & "\"
    fileNm1 = "file1.xlsx"
    fileNm2 = "file2.xlsx"

    filePath1 = folderPath & fileNm1
    filePath2 = folderPath & fileNm2

    If IsWorkBookOpen(filePath1) Then
        Set wbA = Workbooks(fileNm1)
    Else
        Set wbA = Workbooks.Open(filePath1)
    End If


    If IsWorkBookOpen(filePath2) Then
        Set wbB = Workbooks.Open(fileNm2)
    Else
        Set wbB = Workbooks.Open(filePath2)
    End If


    ' your code here
End Sub

Function IsWorkBookOpen(FileName As String)
    Dim ff As Long, ErrNo As Long

    On Error Resume Next
    ff = FreeFile()
    Open FileName For Input Lock Read As #ff
    Close ff
    ErrNo = Err
    On Error GoTo 0

    Select Case ErrNo
    Case 0: IsWorkBookOpen = False
    Case 70: IsWorkBookOpen = True
    Case Else: Error ErrNo
    End Select
End Function

Using Prompt to select the file use below code.

Dim wbA As Workbook
Dim wbB As Workbook

Sub MySubRoutine()
    Dim folderPath As String, fileNm1 As String, fileNm2 As String, filePath1 As String, filePath2 As String

    Dim filePath As String
    cmdBrowse_Click filePath, 1

    filePath1 = filePath

    'reset the variable
    filePath = vbNullString

    cmdBrowse_Click filePath, 2
    filePath2 = filePath

   fileNm1 = GetFileName(filePath1, "\")
   fileNm2 = GetFileName(filePath2, "\")

    If IsWorkBookOpen(filePath1) Then
        Set wbA = Workbooks(fileNm1)
    Else
        Set wbA = Workbooks.Open(filePath1)
    End If


    If IsWorkBookOpen(filePath2) Then
        Set wbB = Workbooks.Open(fileNm2)
    Else
        Set wbB = Workbooks.Open(filePath2)
    End If


    ' your code here
End Sub

Function IsWorkBookOpen(FileName As String)
    Dim ff As Long, ErrNo As Long

    On Error Resume Next
    ff = FreeFile()
    Open FileName For Input Lock Read As #ff
    Close ff
    ErrNo = Err
    On Error GoTo 0

    Select Case ErrNo
    Case 0: IsWorkBookOpen = False
    Case 70: IsWorkBookOpen = True
    Case Else: Error ErrNo
    End Select
End Function

Private Sub cmdBrowse_Click(ByRef filePath As String, num As Integer)

    Dim fd As FileDialog
    Set fd = Application.FileDialog(msoFileDialogFilePicker)
    fd.AllowMultiSelect = False
    fd.Title = "Select workbook " & num
    fd.InitialView = msoFileDialogViewSmallIcons

    Dim FileChosen As Integer

    FileChosen = fd.Show

    fd.Filters.Clear
    fd.Filters.Add "Excel macros", "*.xlsx"


    fd.FilterIndex = 1



    If FileChosen <> -1 Then
        MsgBox "You chose cancel"
        filePath = ""
    Else
        filePath = fd.SelectedItems(1)
    End If

End Sub

Function GetFileName(fullName As String, pathSeparator As String) As String

    Dim i As Integer
    Dim iFNLenght As Integer
    iFNLenght = Len(fullName)

    For i = iFNLenght To 1 Step -1
        If Mid(fullName, i, 1) = pathSeparator Then Exit For
    Next

    GetFileName = Right(fullName, iFNLenght - i)

End Function

How can I remove a button or make it invisible in Android?

First make the button invisible in xml file.Then set button visible in java code if needed.

Button resetButton=(Button)findViewById(R.id.my_button_del);
resetButton.setVisibility(View.VISIBLE); //To set visible

Xml:

<Button
android:text="Delete"
android:id="@+id/my_button_del"
android:layout_width="72dp" 
android:layout_height="40dp"
android:visibility="invisible"/>

JPA - Persisting a One to Many relationship

You have to set the associatedEmployee on the Vehicle before persisting the Employee.

Employee newEmployee = new Employee("matt");
vehicle1.setAssociatedEmployee(newEmployee);
vehicles.add(vehicle1);

newEmployee.setVehicles(vehicles);

Employee savedEmployee = employeeDao.persistOrMerge(newEmployee);

Permutation of array

This a 2-permutation for a list wrapped in an iterator

import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

/* all permutations of two objects 
 * 
 * for ABC: AB AC BA BC CA CB
 * 
 * */
public class ListPermutation<T> implements Iterator {

    int index = 0;
    int current = 0;
    List<T> list;

    public ListPermutation(List<T> e) {
        list = e;
    }

    public boolean hasNext() {
        return !(index == list.size() - 1 && current == list.size() - 1);
    }

    public List<T> next() {
        if(current == index) {
            current++;
        }
        if (current == list.size()) {
            current = 0;
            index++;
        }
        List<T> output = new LinkedList<T>();
        output.add(list.get(index));
        output.add(list.get(current));
        current++;
        return output;
    }

    public void remove() {
    }

}

How to use OpenFileDialog to select a folder?

There is a hackish solution using OpenFileDialog where ValidateNames and CheckFileExists are both set to false and FileName is given a mock value to indicate that a directory is selected.

I say hack because it is confusing to users about how to select a folder. They need to be in the desired folder and then just press Open while file name says "Folder Selection."

C# Folder selection dialog

This is based on Select file or folder from the same dialog by Denis Stankovski.

OpenFileDialog folderBrowser = new OpenFileDialog();
// Set validate names and check file exists to false otherwise windows will
// not let you select "Folder Selection."
folderBrowser.ValidateNames = false;
folderBrowser.CheckFileExists = false;
folderBrowser.CheckPathExists = true;
// Always default to Folder Selection.
folderBrowser.FileName = "Folder Selection.";
if (folderBrowser.ShowDialog() == DialogResult.OK)
{
    string folderPath = Path.GetDirectoryName(folderBrowser.FileName);
    // ...
}

How can I see an the output of my C programs using Dev-C++?

You can open a command prompt (Start -> Run -> cmd, use the cd command to change directories) and call your program from there, or add a getchar() call at the end of the program, which will wait until you press Enter. In Windows, you can also use system("pause"), which will display a "Press enter to continue..." (or something like that) message.

Comma separated results in SQL

If you're stuck with SQL Server <2017, you can use GroupConcat. The syntax and the performance is far better than the FOR XML PATH sollution.

Installation:

-- https://codeplexarchive.blob.core.windows.net/archive/projects/groupconcat/groupconcat.zip
create assembly [GroupConcat] from 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with permission_set = safe;
create aggregate [dbo].[GROUP_CONCAT]    (@VALUE [nvarchar](4000))                                                      returns[nvarchar](max) external name [GroupConcat].[GroupConcat.GROUP_CONCAT];
create aggregate [dbo].[GROUP_CONCAT_D]  (@VALUE [nvarchar](4000), @DELIMITER [nvarchar](4))                            returns[nvarchar](max) external name [GroupConcat].[GroupConcat.GROUP_CONCAT_D];
create aggregate [dbo].[GROUP_CONCAT_DS] (@VALUE [nvarchar](4000), @DELIMITER [nvarchar](4), @SORT_ORDER [tinyint])     returns[nvarchar](max) external name [GroupConcat].[GroupConcat.GROUP_CONCAT_DS];
create aggregate [dbo].[GROUP_CONCAT_S]  (@VALUE [nvarchar](4000), @SORT_ORDER [tinyint])                               returns[nvarchar](max) external name [GroupConcat].[GroupConcat.GROUP_CONCAT_S];

go

Usage:

declare @liststr varchar(max)
select @liststr = dbo.group_concat_d(institutionname, ',')
from education
where studentnumber = '111'
group by studentnumber;
select @liststr

GroupConcat does not support ordering, though. You could use PIVOT, CTE's and windows functions if you need ordering:

drop table if exists #students;
create table #students (
    name        varchar(20),
    institution varchar(20),
    year        int -- order by year
)
go

insert into #students(name, institution, year)
values
    ('Simon', 'INSTITUTION1', 2005),
    ('Simon', 'INSTITUTION2', 2008);

with cte as (
    select name,
           institution,
           rn = row_number() over (partition by name order by year)
    from #students
)
select name,
       [1] +
       isnull((',' + [2]), '') +
       isnull((',' + [3]), '') +
       isnull((',' + [4]), '') +
       isnull((',' + [5]), '') +
       isnull((',' + [6]), '') +
       isnull((',' + [7]), '') +
       isnull((',' + [8]), '') +
       isnull((',' + [9]), '') +
       isnull((',' + [10]), '') +
       isnull((',' + [11]), '') +
       isnull((',' + [12]), '') +
       isnull((',' + [13]), '') +
       isnull((',' + [14]), '') +
       isnull((',' + [15]), '') +
       isnull((',' + [16]), '') +
       isnull((',' + [17]), '') +
       isnull((',' + [18]), '') +
       isnull((',' + [19]), '') +
       isnull((',' + [20]), '')
from cte
    pivot (
    max(institution)
    for rn in ([1], [2], [3], [4],[5],[6],[7],[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18],[19],[20])
    ) as piv

SecurityException: Permission denied (missing INTERNET permission?)

Well it's a very confusing kind of bug. There could be many reasons:

  1. You are not mentioning the permissions in right place. Like right above application.
  2. You are not using small letters.
  3. In some case you also have to add Network state permission.
  4. One which was my case there are some blank lines in manifest lines. Like there might be a blank line between permission tag and application line. Remove them and you are done. Hope it will help

How can I import a database with MySQL from terminal?

  1. Open the MySQL Command Line Client and type in your password

  2. Change to the database you want to use for importing the .sql file data into. Do this by typing:

    USE your_database_name
    
  3. Now locate the .sql file you want to execute.
    If the file is located in the main local C: drive directory and the .sql script file name is currentSqlTable.sql, you would type the following:

    \. C:\currentSqlTable.sql
    

    and press Enter to execute the SQL script file.

Pass multiple optional parameters to a C# function

Use a parameter array with the params modifier:

public static int AddUp(params int[] values)
{
    int sum = 0;
    foreach (int value in values)
    {
        sum += value;
    }
    return sum;
}

If you want to make sure there's at least one value (rather than a possibly empty array) then specify that separately:

public static int AddUp(int firstValue, params int[] values)

(Set sum to firstValue to start with in the implementation.)

Note that you should also check the array reference for nullity in the normal way. Within the method, the parameter is a perfectly ordinary array. The parameter array modifier only makes a difference when you call the method. Basically the compiler turns:

int x = AddUp(4, 5, 6);

into something like:

int[] tmp = new int[] { 4, 5, 6 };
int x = AddUp(tmp);

You can call it with a perfectly normal array though - so the latter syntax is valid in source code as well.

Convert seconds to hh:mm:ss in Python

Read up on the datetime module.

SilentGhost's answer has the details my answer leaves out and is reposted here:

>>> a = datetime.timedelta(seconds=65)
datetime.timedelta(0, 65)
>>> str(a)
'0:01:05'

Label word wrapping

If you want some dynamic sizing in conjunction with a word-wrapping label you can do the following:

  1. Put the label inside a panel
  2. Handle the ClientSizeChanged event for the panel, making the label fill the space:

    private void Panel2_ClientSizeChanged(object sender, EventArgs e)
    {
        label1.MaximumSize = new Size((sender as Control).ClientSize.Width - label1.Left, 10000);
    }
    
  3. Set Auto-Size for the label to true

  4. Set Dock for the label to Fill

Update Android SDK Tool to 22.0.4(Latest Version) from 22.0.1

I faced the same issue, I tried the below solution and it worked for me In Android SDK Manager Window, click on Tools->Options-> under "Others", check "Force https://... sources to be fetched using http://..."

Installing Python 2.7 on Windows 8

Type this in Windows PowerShell or CMD:

"[Environment]::SetEnvironmentVariable("Path", "$env:Path;C:\Python27", "User")"

After running the command, please restart PowerShell or CMD. If it still doesn't work, restart your PC.

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

You can use selectExpr to make it a little cleaner:

df.selectExpr("cast(year as int) as year", "upper(make) as make",
    "model", "comment", "blank")

How to convert a pandas DataFrame subset of columns AND rows into a numpy array?

Perhaps something like this for the first problem, you can simply access the columns by their names:

>>> df = pd.DataFrame(np.random.rand(4,5), columns = list('abcde'))
>>> df[df['c']>.5][['b','e']]
          b         e
1  0.071146  0.132145
2  0.495152  0.420219

For the second problem:

>>> df[df['c']>.5][['b','e']].values
array([[ 0.07114556,  0.13214495],
       [ 0.49515157,  0.42021946]])

How Do I Take a Screen Shot of a UIView?

I created this extension for save a screen shot from UIView

extension UIView {
func saveImageFromView(path path:String) {
    UIGraphicsBeginImageContextWithOptions(bounds.size, false, UIScreen.mainScreen().scale)
    drawViewHierarchyInRect(bounds, afterScreenUpdates: true)
    let image = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()
    UIImageJPEGRepresentation(image, 0.4)?.writeToFile(path, atomically: true)

}}

call:

let pathDocuments = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true).first!
let pathImage = "\(pathDocuments)/\(user!.usuarioID.integerValue).jpg"
reportView.saveImageFromView(path: pathImage)

If you want to create a png must change:

UIImageJPEGRepresentation(image, 0.4)?.writeToFile(path, atomically: true)

by

UIImagePNGRepresentation(image)?.writeToFile(path, atomically: true)

What is the proper way to comment functions in Python?

Use a docstring, as others have already written.

You can even go one step further and add a doctest to your docstring, making automated testing of your functions a snap.

Adding an image to a project in Visual Studio

You need to turn on Show All Files option on solution pane toolbar and include this file manually.

Maximum size of a varchar(max) variable

As far as I can tell there is no upper limit in 2008.

In SQL Server 2005 the code in your question fails on the assignment to the @GGMMsg variable with

Attempting to grow LOB beyond maximum allowed size of 2,147,483,647 bytes.

the code below fails with

REPLICATE: The length of the result exceeds the length limit (2GB) of the target large type.

However it appears these limitations have quietly been lifted. On 2008

DECLARE @y VARCHAR(MAX) = REPLICATE(CAST('X' AS VARCHAR(MAX)),92681); 

SET @y = REPLICATE(@y,92681);

SELECT LEN(@y) 

Returns

8589767761

I ran this on my 32 bit desktop machine so this 8GB string is way in excess of addressable memory

Running

select internal_objects_alloc_page_count
from sys.dm_db_task_space_usage
WHERE session_id = @@spid

Returned

internal_objects_alloc_page_co 
------------------------------ 
2144456    

so I presume this all just gets stored in LOB pages in tempdb with no validation on length. The page count growth was all associated with the SET @y = REPLICATE(@y,92681); statement. The initial variable assignment to @y and the LEN calculation did not increase this.

The reason for mentioning this is because the page count is hugely more than I was expecting. Assuming an 8KB page then this works out at 16.36 GB which is obviously more or less double what would seem to be necessary. I speculate that this is likely due to the inefficiency of the string concatenation operation needing to copy the entire huge string and append a chunk on to the end rather than being able to add to the end of the existing string. Unfortunately at the moment the .WRITE method isn't supported for varchar(max) variables.

Addition

I've also tested the behaviour with concatenating nvarchar(max) + nvarchar(max) and nvarchar(max) + varchar(max). Both of these allow the 2GB limit to be exceeded. Trying to then store the results of this in a table then fails however with the error message Attempting to grow LOB beyond maximum allowed size of 2147483647 bytes. again. The script for that is below (may take a long time to run).

DECLARE @y1 VARCHAR(MAX) = REPLICATE(CAST('X' AS VARCHAR(MAX)),2147483647); 
SET @y1 = @y1 + @y1;
SELECT LEN(@y1), DATALENGTH(@y1)  /*4294967294, 4294967292*/


DECLARE @y2 NVARCHAR(MAX) = REPLICATE(CAST('X' AS NVARCHAR(MAX)),1073741823); 
SET @y2 = @y2 + @y2;
SELECT LEN(@y2), DATALENGTH(@y2)  /*2147483646, 4294967292*/


DECLARE @y3 NVARCHAR(MAX) = @y2 + @y1
SELECT LEN(@y3), DATALENGTH(@y3)   /*6442450940, 12884901880*/

/*This attempt fails*/
SELECT @y1 y1, @y2 y2, @y3 y3
INTO Test

Regex allow a string to only contain numbers 0 - 9 and limit length to 45

A combination of both attempts is probably what you need:

^[0-9]{1,45}$

How do you use String.substringWithRange? (or, how do Ranges work in Swift?)

You can use any of the substring methods in a Swift String extension I wrote https://bit.ly/JString.

var string = "hello"
var sub = string.substringFrom(3) // or string[3...5]
println(sub)// "lo"

Host binding and Host listening

@HostListener is a decorator for the callback/event handler method, so remove the ; at the end of this line:

@HostListener('click', ['$event.target']);

Here's a working plunker that I generated by copying the code from the API docs, but I put the onClick() method on the same line for clarity:

import {Component, HostListener, Directive} from 'angular2/core';

@Directive({selector: 'button[counting]'})
class CountClicks {
  numberOfClicks = 0;
  @HostListener('click', ['$event.target']) onClick(btn) {
    console.log("button", btn, "number of clicks:", this.numberOfClicks++);
  }
}
@Component({
  selector: 'my-app',
  template: `<button counting>Increment</button>`,
  directives: [CountClicks]
})
export class AppComponent {
  constructor() { console.clear(); }
}

Host binding can also be used to listen to global events:

To listen to global events, a target must be added to the event name. The target can be window, document or body (reference)

@HostListener('document:keyup', ['$event'])
handleKeyboardEvent(kbdEvent: KeyboardEvent) { ... }

What is the best regular expression to check if a string is a valid URL?

I found the following Regex for URLs, tested successfully with 500+ URLs:

/\b(?:(?:https?|ftp):\/\/)(?:\S+(?::\S*)?@)?(?:(?!10(?:\.\d{1,3}){3})(?!127(?:\.\d{1,3}){3})(?!169\.254(?:\.\d{1,3}){2})(?!192\.168(?:\.\d{1,3}){2})(?!172\.(?:1[6-9]|2\d|3[0-1])(?:\.\d{1,3}){2})(?:[1-9]\d?|1\d\d|2[01]\d|22[0-3])(?:\.(?:1?\d{1,2}|2[0-4]\d|25[0-5])){2}(?:\.(?:[1-9]\d?|1\d\d|2[0-4]\d|25[0-4]))|(?:(?:[a-z\x{00a1}-\x{ffff}0-9]+-?)*[a-z\x{00a1}-\x{ffff}0-9]+)(?:\.(?:[a-z\x{00a1}-\x{ffff}0-9]+-?)*[a-z\x{00a1}-\x{ffff}0-9]+)*(?:\.(?:[a-z\x{00a1}-\x{ffff}]{2,})))(?::\d{2,5})?(?:\/[^\s]*)?\b/gi

I know it looks ugly, but the good thing is that it works. :)

Explanation and demo with 581 random URLs on regex101.

Source: In search of the perfect URL validation regex

Can anyone explain python's relative imports?

Checking it out in python3:

python -V
Python 3.6.5

Example1:

.
+-- parent.py
+-- start.py
+-- sub
    +-- relative.py

- start.py
import sub.relative

- parent.py
print('Hello from parent.py')

- sub/relative.py
from .. import parent

If we run it like this(just to make sure PYTHONPATH is empty):

PYTHONPATH='' python3 start.py

Output:

Traceback (most recent call last):
  File "start.py", line 1, in <module>
    import sub.relative
  File "/python-import-examples/so-example-v1/sub/relative.py", line 1, in <module>
    from .. import parent
ValueError: attempted relative import beyond top-level package

If we change import in sub/relative.py

- sub/relative.py
import parent

If we run it like this:

PYTHONPATH='' python3 start.py

Output:

Hello from parent.py

Example2:

.
+-- parent.py
+-- sub
    +-- relative.py
    +-- start.py

- parent.py
print('Hello from parent.py')

- sub/relative.py
print('Hello from relative.py')

- sub/start.py
import relative
from .. import parent

Run it like:

PYTHONPATH='' python3 sub/start.py

Output:

Hello from relative.py
Traceback (most recent call last):
  File "sub/start.py", line 2, in <module>
    from .. import parent
ValueError: attempted relative import beyond top-level package

If we change import in sub/start.py:

- sub/start.py
import relative
import parent

Run it like:

PYTHONPATH='' python3 sub/start.py

Output:

Hello from relative.py
Traceback (most recent call last):
  File "sub/start.py", line 3, in <module>
    import parent
ModuleNotFoundError: No module named 'parent'

Run it like:

PYTHONPATH='.' python3 sub/start.py

Output:

Hello from relative.py
Hello from parent.py

Also it's better to use import from root folder, i.e.:

- sub/start.py
import sub.relative
import parent

Run it like:

PYTHONPATH='.' python3 sub/start.py

Output:

Hello from relative.py
Hello from parent.py

How to access shared folder without giving username and password

I found one way to access the shared folder without giving the username and password.

We need to change the share folder protect settings in the machine where the folder has been shared.

Go to Control Panel > Network and sharing center > Change advanced sharing settings > Enable Turn Off password protect sharing option.

By doing the above settings we can access the shared folder without any username/password.

Laravel: Validation unique on update

My solution:

$rules = $user->isDirty('email') ? \User::$rules : array_except(\User::$rules, 'email');

Then in validation:

$validator = \Validator::make(\Input::all(), $rules, \User::$messages);

The logic is if the email address in the form is different, we need to validated it, if the email hasn't changed, we don't need to validate, so remove that rule from validation.

How to fix java.net.SocketException: Broken pipe?

In our case we experienced this while performing a load test on our app server. The issue turned out that we need to add additional memory to our JVM because it was running out. This resolved the issue.

Try increasing the memory available to the JVM and or monitor the memory usage when you get those errors.

How to remove \n from a list element?

If you want to remove \n from the last element only, use this:

t[-1] = t[-1].strip()

If you want to remove \n from all the elements, use this:

t = map(lambda s: s.strip(), t)

You might also consider removing \n before splitting the line:

line = line.strip()
# split line...

How to pass variables from one php page to another without form?

You can pass via GET. So if you want to pass the value foobar from PageA.php to PageB.php, call it as PageB.php?value=foobar.

In PageB.php, you can access it this way:

$value = $_GET['value'];

What's the difference between Visual Studio Community and other, paid versions?

Visual Studio Community is same (almost) as professional edition. What differs is that VS community do not have TFS features, and the licensing is different. As stated by @Stefan.

The different versions on VS are compared here - https://www.visualstudio.com/en-us/products/compare-visual-studio-2015-products-vs

enter image description here

what is this value means 1.845E-07 in excel?

1.84E-07 is the exact value, represented using scientific notation, also known as exponential notation.

1.845E-07 is the same as 0.0000001845. Excel will display a number very close to 0 as 0, unless you modify the formatting of the cell to display more decimals.

C# however will get the actual value from the cell. The ToString method use the e-notation when converting small numbers to a string.

You can specify a format string if you don't want to use the e-notation.

Install a module using pip for specific python version

I had Python 2.7 installed via chocolatey on Windows and found pip2.7.exe in C:\tools\python2\Scripts.

Using this executable instead of the pip command installed the correct module for me (requests for Python 2.7).

Copy an entire worksheet to a new worksheet in Excel 2010

It is simpler just to run an exact copy like below to put the copy in as the last sheet

Sub Test()
Dim ws1 As Worksheet
Set ws1 = ThisWorkbook.Worksheets("Master")
ws1.Copy ThisWorkbook.Sheets(Sheets.Count)
End Sub

What is the difference between a symbolic link and a hard link?

Some nice intuition that might help, using any Linux(ish) console.

Create two files:

$ touch foo; touch bar

Enter some Data into them:

$ echo "Cat" > foo
$ echo "Dog" > bar

(Actually, I could have used echo in the first place, as it creates the files if they don't exist... but never mind that.)

And as expected:

$cat foo; cat bar
Cat
Dog

Let's create hard and soft links:

$ ln foo foo-hard
$ ln -s bar bar-soft

Let's see what just happened:

$ ls -l

foo
foo-hard
bar
bar-soft -> bar

Changing the name of foo does not matter:

$ mv foo foo-new
$ cat foo-hard
Cat

foo-hard points to the inode, the contents, of the file - that wasn't changed.

$ mv bar bar-new
$ ls bar-soft
bar-soft
$ cat bar-soft  
cat: bar-soft: No such file or directory

The contents of the file could not be found because the soft link points to the name, that was changed, and not to the contents.

Likewise, If foo is deleted, foo-hard still holds the contents; if bar is deleted, bar-soft is just a link to a non-existing file.

Cannot retrieve string(s) from preferences (settings)

All your exercise conditionals are separate and the else is only tied to the last if statement. Use else if to bind them all together in the way I believe you intend.

Which programming language for cloud computing?

Depends on which "cloud" you would want to use. If it is Google App Engine, you can use Java or Python. Groovy too is supported on Google App Engine which runs on jvm. If you are going with Amazon, you can pretty much install any OS (Amazon Machine Images) you would like with any application server and use any language depending on the application servers support for the language. But doing something like that would mean a lot of technical understanding of scalability concepts. Some of the services might be provided off the shelf like DB services, storage etc. I heard about ruby and Heroku (another cloud application platform). But dont have experience with it.

Personally I prefer Java/Groovy for such things because of the vast libraries and tools available.

Javascript: convert 24-hour time-of-day string to 12-hour time with AM/PM and no timezone

To get AM/PM, Check if the hour portion is less than 12, then it is AM, else PM.

To get the hour, do (hour % 12) || 12.

This should do it:

var timeString = "18:00:00";
var H = +timeString.substr(0, 2);
var h = H % 12 || 12;
var ampm = (H < 12 || H === 24) ? "AM" : "PM";
timeString = h + timeString.substr(2, 3) + ampm;

http://jsfiddle.net/Skwt7/4/

That assumes that AM times are formatted as, eg, 08:00:00. If they are formatted without the leading zero, you would have to test the position of the first colon:

var hourEnd = timeString.indexOf(":");
var H = +timeString.substr(0, hourEnd);
var h = H % 12 || 12;
var ampm = (H < 12 || H === 24) ? "AM" : "PM";
timeString = h + timeString.substr(hourEnd, 3) + ampm;

http://jsfiddle.net/Skwt7/3/

HQL ERROR: Path expected for join

select u from UserGroup ug inner join ug.user u 
where ug.group_id = :groupId 
order by u.lastname

As a named query:

@NamedQuery(
  name = "User.findByGroupId",
  query =
    "SELECT u FROM UserGroup ug " +
    "INNER JOIN ug.user u WHERE ug.group_id = :groupId ORDER BY u.lastname"
)

Use paths in the HQL statement, from one entity to the other. See the Hibernate documentation on HQL and joins for details.

Responsive Google Map?

My solution based on eugenemail response:

1. HTML - Google Maps API

Get API Key

<script src="https://maps.googleapis.com/maps/api/js?key=YOUR_API_KEY&callback=initMap"></script>

2. HTML - Canvas

<div id="map_canvas"></div>

3. CSS - Map canvas

#map_canvas {
    height: 400px;
}

4. JavaScript

function initialize() {
    var lat = 40.759300;
    var lng = -73.985712;
    var map_center = new google.maps.LatLng(lat, lng);
    var mapOptions = {
        center: map_center,
        zoom: 16,
        mapTypeId: google.maps.MapTypeId.ROADMAP
    };
    var mapCanvas = document.getElementById("map_canvas");
    var map = new google.maps.Map(mapCanvas, mapOptions);
    new google.maps.Marker({
        map: map,
        draggable: false,
        position: new google.maps.LatLng(lat, lng)
    });
    google.maps.event.addDomListener(window, 'resize', function() {
        map.setCenter(map_center);
    });
}
initialize();

How to check whether java is installed on the computer

Check the installation directories (typically C:\Program Files (x86) or C:\Program Files) for the java folder. If it contains the JRE you have java installed.

TypeError: 'in <string>' requires string as left operand, not int

You simply need to make cab a string:

cab = '6176'

As the error message states, you cannot do <int> in <string>:

>>> 1 in '123'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'in <string>' requires string as left operand, not int
>>> 

because integers and strings are two totally different things and Python does not embrace implicit type conversion ("Explicit is better than implicit.").

In fact, Python only allows you to use the in operator with a right operand of type string if the left operand is also of type string:

>>> '1' in '123'  # Works!
True
>>>
>>> [] in '123'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'in <string>' requires string as left operand, not list
>>>
>>> 1.0 in '123'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'in <string>' requires string as left operand, not float
>>>
>>> {} in '123'
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'in <string>' requires string as left operand, not dict
>>>

What is a reasonable code coverage % for unit tests (and why)?

In my opinion, the answer is "It depends on how much time you have". I try to achieve 100% but I don't make a fuss if I don't get it with the time I have.

When I write unit tests, I wear a different hat compared to the hat I wear when developing production code. I think about what the tested code claims to do and what are the situations that can possible break it.

I usually follow the following criteria or rules:

  1. That the Unit Test should be a form of documentation on what's the expected behavior of my codes, ie. the expected output given a certain input and the exceptions it may throw that clients may want to catch (What the users of my code should know?)

  2. That the Unit Test should help me discover the what if conditions that I may not yet have thought of. (How to make my code stable and robust?)

If these two rules doesn't produce 100% coverage then so be it. But once, I have the time, I analyze the uncovered blocks and lines and determine if there are still test cases without unit tests or if the code needs to be refactored to eliminate the unecessary codes.

Bootstrap - floating navbar button right

Create a separate ul.nav for just that list item and float that ul right.

jsFiddle

How to change an image on click using CSS alone?

You could use an <a> tag with different styles:

a:link    { }
a:visited { }
a:hover   { }
a:active  { }

I'd recommend using that in conjunction with CSS sprites: https://css-tricks.com/css-sprites/

Error:Unable to locate adb within SDK in Android Studio

The ADB is now located in the Android SDK platform-tools.

  1. Check your [sdk directory]/platform-tools directory and if it does not exist, then open the SDK manager in the Android Studio (a button somewhere in the top menu, android logo with a down arrow), switch to SDK tools tab and and select/install the Android SDK Platform-tools.

enter image description here enter image description here enter image description here

  1. Alternatively, you can try the standalone SDK Manager: Open the SDK manager and you should see a "Launch Standalone SDK manager" link somewhere at the bottom of the settings window. Click and open the standalone SDK manager, then install/update the

"Tools > Android SDK platform tools".

  1. If the above does not solve the problem, try reinstalling the tools: open the "Standalone SDK manager" and uninstall the Android SDK platform-tools, delete the [your sdk directory]/platform-tools directory completely and install it again using the SDK manager.

  2. Check your antivirus chest. Sometimes the Antivirus program thinks adb.exe is a virus. If you find it there please restore the file and it will start working. You can also put adb.exe as a safe file in you Antivirus program.

enter image description here enter image description here

Hope this helps!

AngularJS $resource RESTful example

you can just do $scope.todo = Todo.get({ id: 123 }). .get() and .query() on a Resource return an object immediately and fill it with the result of the promise later (to update your template). It's not a typical promise which is why you need to either use a callback or the $promise property if you have some special code you want executed after the call. But there is no need to assign it to your scope in a callback if you are only using it in the template.

Get pandas.read_csv to read empty values as empty string instead of nan

I added a ticket to add an option of some sort here:

https://github.com/pydata/pandas/issues/1450

In the meantime, result.fillna('') should do what you want

EDIT: in the development version (to be 0.8.0 final) if you specify an empty list of na_values, empty strings will stay empty strings in the result

How to remove all click event handlers using jQuery?

Is there a way to remove all previous click events that have been assigned to a button?

$('#saveBtn').unbind('click').click(function(){saveQuestion(id)});

Classes residing in App_Code is not accessible

Go to the page from where you want to access the App_code class, and then add the namespace of the app_code class. You need to provide a using statement, as follows:

using WebApplication3.App_Code;

After that, you will need to go to the app_code class property and set the 'Build Action' to 'Compile'.

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

The key "Transactional Resources" looks like you are talking to the database without a proper transaction. Make sure transaction management is configured properly and no invocation path to the DAO exists that doesn't run under a @Transactional annotation. This can easily happen when you configured transaction management on the Controller level but are invoking DAOs in a timer or are using @PostConstruct annotations. I wrote it up here http://georgovassilis.blogspot.nl/2014/01/tomcat-spring-and-memory-leaks-when.html

Edit: It looks like this is (also?) a bug with spring-data-jpa which has been fixed with v1.4.3. I looked it up in the spring-data-jpa sources of LockModeRepositoryPostProcessor which sets the "Transactional Resources" key. In 1.4.3 it also clears the key again.

Best practice: PHP Magic Methods __set and __get

I have been exactly in your case in the past. And I went for magic methods.

This was a mistake, the last part of your question says it all :

  • this is slower (than getters/setters)
  • there is no auto-completion (and this is a major problem actually), and type management by the IDE for refactoring and code-browsing (under Zend Studio/PhpStorm this can be handled with the @property phpdoc annotation but that requires to maintain them: quite a pain)
  • the documentation (phpdoc) doesn't match how your code is supposed to be used, and looking at your class doesn't bring much answers as well. This is confusing.
  • added after edit: having getters for properties is more consistent with "real" methods where getXXX() is not only returning a private property but doing real logic. You have the same naming. For example you have $user->getName() (returns private property) and $user->getToken($key) (computed). The day your getter gets more than a getter and needs to do some logic, everything is still consistent.

Finally, and this is the biggest problem IMO : this is magic. And magic is very very bad, because you have to know how the magic works to use it properly. That's a problem I've met in a team: everybody has to understand the magic, not just you.

Getters and setters are a pain to write (I hate them) but they are worth it.

Pass Model To Controller using Jquery/Ajax

Looks like your IndexPartial action method has an argument which is a complex object. If you are passing a a lot of data (complex object), It might be a good idea to convert your action method to a HttpPost action method and use jQuery post to post data to that. GET has limitation on the query string value.

[HttpPost]
public PartialViewResult IndexPartial(DashboardViewModel m)
{
   //May be you want to pass the posted model to the parial view?
   return PartialView("_IndexPartial");
}

Your script should be

var url = "@Url.Action("IndexPartial","YourControllerName")";

var model = { Name :"Shyju", Location:"Detroit"};

$.post(url, model, function(res){
   //res contains the markup returned by the partial view
   //You probably want to set that to some Div.
   $("#SomeDivToShowTheResult").html(res);
});

Assuming Name and Location are properties of your DashboardViewModel class and SomeDivToShowTheResult is the id of a div in your page where you want to load the content coming from the partialview.

Sending complex objects?

You can build more complex object in js if you want. Model binding will work as long as your structure matches with the viewmodel class

var model = { Name :"Shyju", 
              Location:"Detroit", 
              Interests : ["Code","Coffee","Stackoverflow"]
            };

$.ajax({
    type: "POST",
    data: JSON.stringify(model),
    url: url,
    contentType: "application/json"
}).done(function (res) {
    $("#SomeDivToShowTheResult").html(res);
});

For the above js model to be transformed to your method parameter, Your View Model should be like this.

public class DashboardViewModel
{
  public string Name {set;get;}
  public string Location {set;get;}
  public List<string> Interests {set;get;}
}

And in your action method, specify [FromBody]

[HttpPost]
public PartialViewResult IndexPartial([FromBody] DashboardViewModel m)
{
    return PartialView("_IndexPartial",m);
}

Getting Raw XML From SOAPMessage in Java

If you need formatting the xml string to xml, try this:

String xmlStr = "your-xml-string";
Source xmlInput = new StreamSource(new StringReader(xmlStr));
Transformer transformer = TransformerFactory.newInstance().newTransformer();
transformer.setOutputProperty(OutputKeys.INDENT, "yes");
transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
transformer.transform(xmlInput,
        new StreamResult(new FileOutputStream("response.xml")));

How do I start PowerShell from Windows Explorer?

In Windows Explorer, just go to the Address Bar at the top (keyboard shortcuts: Alt+D or Ctrl+L) and type powershell or powershell_ise and press Enter. A PowerShell command window opens with the current directory.

JavaScript console.log causes error: "Synchronous XMLHttpRequest on the main thread is deprecated..."

This happened to me when I was being lazy and included a script tag as part of the content that was being returned. As such:

Partial HTML Content:

<div> 
 SOME CONTENT HERE
</div>
<script src="/scripts/script.js"></script> 

It appears, at least in my case, that if you return HTML content like that via xhr, you will cause jQuery to make a call to get that script. That call happens with an async flag false since it assumes you need the script to continue loading.

In situations like this one you'd be better served by looking into a binding framework of some kind and just returning a JSON object, or depending on your backend and templating you could change how you load your scripts.

You could also use jQuery's getScript() to grab relevant scripts. Here is a fiddle, It's just a straight copy of the jQuery example, but I'm not seeing any warnings thrown when scripts are loaded that way.

Example

<script>
var url = "/scripts/script.js";
$.getScript(url);
</script>

http://jsfiddle.net/49tkL0qd/

Best practices for styling HTML emails

In addition to the answers posted here, make sure you read this article:

http://24ways.org/2009/rock-solid-html-emails

How to test the `Mosquitto` server?

Start the Mosquitto Broker
Open the terminal and type

mosquitto_sub -h 127.0.0.1 -t topic

Open another terminal and type
mosquitto_pub -h 127.0.0.1 -t topic -m "Hello"

Now you can switch to the previous terminal and there you can able to see the "Hello" Message.One terminal acts as publisher and another one subscriber.

JavaScript Promises - reject vs. throw

TLDR: A function is hard to use when it sometimes returns a promise and sometimes throws an exception. When writing an async function, prefer to signal failure by returning a rejected promise

Your particular example obfuscates some important distinctions between them:

Because you are error handling inside a promise chain, thrown exceptions get automatically converted to rejected promises. This may explain why they seem to be interchangeable - they are not.

Consider the situation below:

checkCredentials = () => {
    let idToken = localStorage.getItem('some token');
    if ( idToken ) {
      return fetch(`https://someValidateEndpoint`, {
        headers: {
          Authorization: `Bearer ${idToken}`
        }
      })
    } else {
      throw new Error('No Token Found In Local Storage')
    }
  }

This would be an anti-pattern because you would then need to support both async and sync error cases. It might look something like:

try {
  function onFulfilled() { ... do the rest of your logic }
  function onRejected() { // handle async failure - like network timeout }
  checkCredentials(x).then(onFulfilled, onRejected);
} catch (e) {
  // Error('No Token Found In Local Storage')
  // handle synchronous failure
} 

Not good and here is exactly where Promise.reject ( available in the global scope ) comes to the rescue and effectively differentiates itself from throw. The refactor now becomes:

checkCredentials = () => {
  let idToken = localStorage.getItem('some_token');
  if (!idToken) {
    return Promise.reject('No Token Found In Local Storage')
  }
  return fetch(`https://someValidateEndpoint`, {
    headers: {
      Authorization: `Bearer ${idToken}`
    }
  })
}

This now lets you use just one catch() for network failures and the synchronous error check for lack of tokens:

checkCredentials()
      .catch((error) => if ( error == 'No Token' ) {
      // do no token modal
      } else if ( error === 400 ) {
      // do not authorized modal. etc.
      }

Pass a string parameter in an onclick function

I am guessing, you are creating a button using JavaScript itself. So, the error in your code is that, it will render in this form

<input type="button" onClick="gotoNode(add)" />'

At this current state, add will be considered as an identifier like variables or function calls. You should escape the value like this

'<input type="button" onClick="gotoNode(\'' + result.name + '\')" />'

How to increase maximum execution time in php

You can try to set_time_limit(n). However, if your PHP setup is running in safe mode, you can only change it from the php.ini file.

How do I get the Session Object in Spring?

Indeed you can access the information from the session even when the session is being destroyed on an HttpSessionLisener by doing:

public void sessionDestroyed(HttpSessionEvent hse) {
    SecurityContextImpl sci = (SecurityContextImpl) hse.getSession().getAttribute("SPRING_SECURITY_CONTEXT");
    // be sure to check is not null since for users who just get into the home page but never get authenticated it will be
    if (sci != null) {
        UserDetails cud = (UserDetails) sci.getAuthentication().getPrincipal();
        // do whatever you need here with the UserDetails
    }
 }

or you could also access the information anywhere you have the HttpSession object available like:

SecurityContextImpl sci = (SecurityContextImpl) session().getAttribute("SPRING_SECURITY_CONTEXT");

the last assuming you have something like:

HttpSession sesssion = ...; // can come from request.getSession(false);

Is there a method that tells my program to quit?

The actual way to end a program, is to call

raise SystemExit

It's what sys.exit does, anyway.

A plain SystemExit, or with None as a single argument, sets the process' exit code to zero. Any non-integer exception value (raise SystemExit("some message")) prints the exception value to sys.stderr and sets the exit code to 1. An integer value sets the process' exit code to the value:

$ python -c "raise SystemExit(4)"; echo $?
4

Best way to clear a PHP array's values

How about $array_name = array(); ?

Iteration ng-repeat only X times in AngularJs

You can use slice method in javascript array object

<div ng-repeat="item in items.slice(0, 4)">{{item}}</div>

Short n sweet

SQL Count for each date

It is most efficient to do your aggregation by integer and then convert back to datetime for presentation.

select 
    cast(daybucket - 1 as datetime) as count_date,
    counted_leads
from 
    (select 
         cast(created_date as int) as DayBucket,
         count(*) as counted_leads
     from mytable
     group by cast(created_date as int) ) as countByDay

Color theme for VS Code integrated terminal

The best colors I've found --which aside from being so beautiful, are very easy to look at too and do not boil my eyes-- are the ones I've found listed in this GitHub repository: VSCode Snazzy

Very Easy Installation:

Copy the contents of snazzy.json into your VS Code "settings.json" file.

(In case you don't know how to open the "settings.json" file, first hit Ctrl+Shift+P and then write Preferences: open settings(JSON) and hit enter).


Notice: For those who have tried ColorTool and it works outside VSCode but not inside VSCode, you've made no mistakes in implementing it, that's just a decision of VSCode developers for the VSCode's terminal to be colored independently.

How to search JSON data in MySQL?

for MySQL all (and 5.7)

SELECT LOWER(TRIM(BOTH 0x22 FROM TRIM(BOTH 0x20 FROM SUBSTRING(SUBSTRING(json_filed,LOCATE('\"ArrayItem\"',json_filed)+LENGTH('\"ArrayItem\"'),LOCATE(0x2C,SUBSTRING(json_filed,LOCATE('\"ArrayItem\"',json_filed)+LENGTH('\"ArrayItem\"')+1,LENGTH(json_filed)))),LOCATE(0x22,SUBSTRING(json_filed,LOCATE('\"ArrayItem\"',json_filed)+LENGTH('\"ArrayItem\"'),LOCATE(0x2C,SUBSTRING(json_filed,LOCATE('\"ArrayItem\"',json_filed)+LENGTH('\"ArrayItem\"')+1,LENGTH(json_filed))))),LENGTH(json_filed))))) AS result FROM `table`;

Unable to find the requested .Net Framework Data Provider. It may not be installed. - when following mvc3 asp.net tutorial

I had the same when following MvcMusicStore Tutorial in Part 4 and replaced the given connection String with this:

add name="MusicStoreEntities" connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;database=MvcMusicStore;User ID=sa;password=" providerName="System.Data.SqlClient"/>

It worked for me.

How to check if a file exists in Documents folder?

Swift 2.0

This is how to check if the file exists using Swift

func isFileExistsInDirectory() -> Bool {
    let paths = NSSearchPathForDirectoriesInDomains(NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true)
    let documentsDirectory: AnyObject = paths[0]
    let dataPath = documentsDirectory.stringByAppendingPathComponent("/YourFileName")

    return NSFileManager.defaultManager().fileExistsAtPath(dataPath)
}

How to save and load numpy.array() data properly?

np.fromfile() has a sep= keyword argument:

Separator between items if file is a text file. Empty (“”) separator means the file should be treated as binary. Spaces (” ”) in the separator match zero or more whitespace characters. A separator consisting only of spaces must match at least one whitespace.

The default value of sep="" means that np.fromfile() tries to read it as a binary file rather than a space-separated text file, so you get nonsense values back. If you use np.fromfile('markers.txt', sep=" ") you will get the result you are looking for.

However, as others have pointed out, np.loadtxt() is the preferred way to convert text files to numpy arrays, and unless the file needs to be human-readable it is usually better to use binary formats instead (e.g. np.load()/np.save()).

Using Vim's tabs like buffers

If you want buffers to work like tabs, check out the tabline plugin.

That uses a single window, and adds a line on the top to simulate the tabs (just showing the list of buffers). This came out a long time ago when tabs were only supported in GVim but not in the command line vim. Since it is only operating with buffers, everything integrates well with the rest of vim.

getting exception "IllegalStateException: Can not perform this action after onSaveInstanceState"

I solved the issue with onconfigurationchanged. The trick is that according to android activity life cycle, when you explicitly called an intent(camera intent, or any other one); the activity is paused and onsavedInstance is called in that case. When rotating the device to a different position other than the one during which the activity was active; doing fragment operations such as fragment commit causes Illegal state exception. There are lots of complains about it. It's something about android activity lifecycle management and proper method calls. To solve it I did this: 1-Override the onsavedInstance method of your activity, and determine the current screen orientation(portrait or landscape) then set your screen orientation to it before your activity is paused. that way the activity you lock the screen rotation for your activity in case it has been rotated by another one. 2-then , override onresume method of activity, and set your orientation mode now to sensor so that after onsaved method is called it will call one more time onconfiguration to deal with the rotation properly.

You can copy/paste this code into your activity to deal with it:

@Override
protected void onSaveInstanceState(Bundle outState) {       
    super.onSaveInstanceState(outState);

    Toast.makeText(this, "Activity OnResume(): Lock Screen Orientation ", Toast.LENGTH_LONG).show();
    int orientation =this.getDisplayOrientation();
    //Lock the screen orientation to the current display orientation : Landscape or Potrait
    this.setRequestedOrientation(orientation);
}

//A method found in stackOverflow, don't remember the author, to determine the right screen orientation independently of the phone or tablet device 
public int getDisplayOrientation() {
    Display getOrient = getWindowManager().getDefaultDisplay();

    int orientation = getOrient.getOrientation();

    // Sometimes you may get undefined orientation Value is 0
    // simple logic solves the problem compare the screen
    // X,Y Co-ordinates and determine the Orientation in such cases
    if (orientation == Configuration.ORIENTATION_UNDEFINED) {
        Configuration config = getResources().getConfiguration();
        orientation = config.orientation;

        if (orientation == Configuration.ORIENTATION_UNDEFINED) {
        // if height and widht of screen are equal then
        // it is square orientation
            if (getOrient.getWidth() == getOrient.getHeight()) {
                orientation = Configuration.ORIENTATION_SQUARE;
            } else { //if widht is less than height than it is portrait
                if (getOrient.getWidth() < getOrient.getHeight()) {
                    orientation = Configuration.ORIENTATION_PORTRAIT;
                } else { // if it is not any of the above it will defineitly be landscape
                    orientation = Configuration.ORIENTATION_LANDSCAPE;
                }
            }
        }
    }
    return orientation; // return value 1 is portrait and 2 is Landscape Mode
}

@Override
public void onResume() {
    super.onResume();
    Toast.makeText(this, "Activity OnResume(): Unlock Screen Orientation ", Toast.LENGTH_LONG).show();
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_SENSOR);
} 

XPath using starts-with function

Use:

//REVENUE_YEAR[starts-with(.,'2552')]/../REGION/text() 

Initializing select with AngularJS and ng-repeat

Thanks to TheSharpieOne for pointing out the ng-selected option. If that had been posted as an answer rather than as a comment, I would have made that the correct answer.

Here's a working JSFiddle: http://jsfiddle.net/coverbeck/FxM3B/5/.

I also updated the fiddle to use the title attribute, which I had left out in my original post, since it wasn't the cause of the problem (but it is the reason I want to use ng-repeat instead of ng-options).

HTML:

<body ng-app ng-controller="AppCtrl">
<div>Operator is: {{filterCondition.operator}}</div>
<select ng-model="filterCondition.operator">
   <option ng-repeat="operator in operators" title="{{operator.title}}" ng-selected="{{operator.value == filterCondition.operator}}" value="{{operator.value}}">{{operator.displayName}}</option>
</select>
</body>

JS:

function AppCtrl($scope) {

    $scope.filterCondition={
        operator: 'eq'
    }

    $scope.operators = [
        {value: 'eq', displayName: 'equals', title: 'The equals operator does blah, blah'},
        {value: 'neq', displayName: 'not equal', title: 'The not equals operator does yada yada'}
     ]
}

Modifying local variable from inside lambda

I know that's an old question, but if you are comfortable with a workaround, considering the fact that the external variable should be final, you can simply do this:

final int[] ordinal = new int[1];
list.forEach(s -> {
    s.setOrdinal(ordinal[0]);
    ordinal[0]++;
});

Maybe not the most elegant, or even the most correct, but it will do.

Getting the computer name in Java

I agree with peterh's answer, so for those of you who like to copy and paste instead of 60 more seconds of Googling:

private String getComputerName()
{
    Map<String, String> env = System.getenv();
    if (env.containsKey("COMPUTERNAME"))
        return env.get("COMPUTERNAME");
    else if (env.containsKey("HOSTNAME"))
        return env.get("HOSTNAME");
    else
        return "Unknown Computer";
}

I have tested this in Windows 7 and it works. If peterh was right the else if should take care of Mac and Linux. Maybe someone can test this? You could also implement Brian Roach's answer inside the else if you wanted extra robustness.

Get month name from number

This is not so helpful if you need to just know the month name for a given number (1 - 12), as the current day doesn't matter.

calendar.month_name[i]

or

calendar.month_abbr[i]

are more useful here.

Here is an example:

import calendar

for month_idx in range(1, 13):
    print (calendar.month_name[month_idx])
    print (calendar.month_abbr[month_idx])
    print ("")

Sample output:

January
Jan

February
Feb

March
Mar

...

Keep CMD open after BAT file executes

Just add @pause at the end.

Example:

@echo off
ipconfig
@pause

Or you can also use:

cmd /k ipconfig

git push >> fatal: no configured push destination

I have faced this error, Previous I had push in root directory, and now I have push another directory, so I could be remove this error and run below commands.

git add .
git commit -m "some comments"
git push --set-upstream origin master

Import Excel spreadsheet columns into SQL Server database

Microsoft Access is another option. You could have a Access database locally on your machine that you import the excel spreadsheets into (wizards available) and link to the the SQL Server database tables via ODBC.

You could then design a query in access that appends data from the Excel spreadsheet to the SQL Server Tables.

How do you display JavaScript datetime in 12 hour AM/PM format?

_x000D_
_x000D_
function formatAMPM(date) {
  var hours = date.getHours();
  var minutes = date.getMinutes();
  var ampm = hours >= 12 ? 'pm' : 'am';
  hours = hours % 12;
  hours = hours ? hours : 12; // the hour '0' should be '12'
  minutes = minutes < 10 ? '0'+minutes : minutes;
  var strTime = hours + ':' + minutes + ' ' + ampm;
  return strTime;
}

console.log(formatAMPM(new Date));
_x000D_
_x000D_
_x000D_

Async always WaitingForActivation

I overcome this issue with if anybody interested. In myMain method i called my readasync method like

Dispatcher.BeginInvoke(new ThreadStart(() => ReadData()));

Everything is fine for me now.

How can I create a UIColor from a hex string?

Several above solutions involve somewhat unnecessary use of NSStrings. This UIColor class extension is bit simpler & faster:

+ colorWithHex:(UInt32)hex alpha:(CGFloat)alpha
{
    return [UIColor colorWithRed:((hex & 0xFF0000) >> 16)/255.0
                           green:((hex & 0x00FF00) >> 8)/255.0
                            blue:( hex & 0x0000FF)/255.0
                           alpha:alpha];
}

and to use it simply:

return [UIColor colorWithHex:0x006400 alpha:1.0]; // HTML darkgreen

Does a favicon have to be 32x32 or 16x16?

I am not sure if/how browsers scale large icons, but The W3C suggests the following1:

The format for the image you have chosen must be 16x16 pixels or 32x32 pixels, using either 8-bit or 24-bit colors. The format of the image must be one of PNG (a W3C standard), GIF, or ICO.


1 w3c.org: How to Add a Favicon to your Site (Draft in development).

How to read from input until newline is found using scanf()?

#include <stdio.h>
#include <conio.h>
#include <stdlib.h>

int main(void)
{
  int i = 0;
  char *a = (char *) malloc(sizeof(char) * 1024);
  while (1) {
    scanf("%c", &a[i]);
    if (a[i] == '\n') {
      break;
    }
    else {
      i++;
    }
  }
  a[i] = '\0';
  i = 0;
  printf("\n");
  while (a[i] != '\0') {
    printf("%c", a[i]);
    i++;
  }
  free(a);
  getch();
  return 0;
}

Convert wchar_t to char

Technically, 'char' could have the same range as either 'signed char' or 'unsigned char'. For the unsigned characters, your range is correct; theoretically, for signed characters, your condition is wrong. In practice, very few compilers will object - and the result will be the same.

Nitpick: the last && in the assert is a syntax error.

Whether the assertion is appropriate depends on whether you can afford to crash when the code gets to the customer, and what you could or should do if the assertion condition is violated but the assertion is not compiled into the code. For debug work, it seems fine, but you might want an active test after it for run-time checking too.

Global keyboard capture in C# application

Here's my code that works:

using System;
using System.ComponentModel;
using System.Diagnostics;
using System.Runtime.InteropServices;

namespace SnagFree.TrayApp.Core
{
    class GlobalKeyboardHookEventArgs : HandledEventArgs
    {
        public GlobalKeyboardHook.KeyboardState KeyboardState { get; private set; }
        public GlobalKeyboardHook.LowLevelKeyboardInputEvent KeyboardData { get; private set; }

        public GlobalKeyboardHookEventArgs(
            GlobalKeyboardHook.LowLevelKeyboardInputEvent keyboardData,
            GlobalKeyboardHook.KeyboardState keyboardState)
        {
            KeyboardData = keyboardData;
            KeyboardState = keyboardState;
        }
    }

    //Based on https://gist.github.com/Stasonix
    class GlobalKeyboardHook : IDisposable
    {
        public event EventHandler<GlobalKeyboardHookEventArgs> KeyboardPressed;

        public GlobalKeyboardHook()
        {
            _windowsHookHandle = IntPtr.Zero;
            _user32LibraryHandle = IntPtr.Zero;
            _hookProc = LowLevelKeyboardProc; // we must keep alive _hookProc, because GC is not aware about SetWindowsHookEx behaviour.

            _user32LibraryHandle = LoadLibrary("User32");
            if (_user32LibraryHandle == IntPtr.Zero)
            {
                int errorCode = Marshal.GetLastWin32Error();
                throw new Win32Exception(errorCode, $"Failed to load library 'User32.dll'. Error {errorCode}: {new Win32Exception(Marshal.GetLastWin32Error()).Message}.");
            }



            _windowsHookHandle = SetWindowsHookEx(WH_KEYBOARD_LL, _hookProc, _user32LibraryHandle, 0);
            if (_windowsHookHandle == IntPtr.Zero)
            {
                int errorCode = Marshal.GetLastWin32Error();
                throw new Win32Exception(errorCode, $"Failed to adjust keyboard hooks for '{Process.GetCurrentProcess().ProcessName}'. Error {errorCode}: {new Win32Exception(Marshal.GetLastWin32Error()).Message}.");
            }
        }

        protected virtual void Dispose(bool disposing)
        {
            if (disposing)
            {
                // because we can unhook only in the same thread, not in garbage collector thread
                if (_windowsHookHandle != IntPtr.Zero)
                {
                    if (!UnhookWindowsHookEx(_windowsHookHandle))
                    {
                        int errorCode = Marshal.GetLastWin32Error();
                        throw new Win32Exception(errorCode, $"Failed to remove keyboard hooks for '{Process.GetCurrentProcess().ProcessName}'. Error {errorCode}: {new Win32Exception(Marshal.GetLastWin32Error()).Message}.");
                    }
                    _windowsHookHandle = IntPtr.Zero;

                    // ReSharper disable once DelegateSubtraction
                    _hookProc -= LowLevelKeyboardProc;
                }
            }

            if (_user32LibraryHandle != IntPtr.Zero)
            {
                if (!FreeLibrary(_user32LibraryHandle)) // reduces reference to library by 1.
                {
                    int errorCode = Marshal.GetLastWin32Error();
                    throw new Win32Exception(errorCode, $"Failed to unload library 'User32.dll'. Error {errorCode}: {new Win32Exception(Marshal.GetLastWin32Error()).Message}.");
                }
                _user32LibraryHandle = IntPtr.Zero;
            }
        }

        ~GlobalKeyboardHook()
        {
            Dispose(false);
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        private IntPtr _windowsHookHandle;
        private IntPtr _user32LibraryHandle;
        private HookProc _hookProc;

        delegate IntPtr HookProc(int nCode, IntPtr wParam, IntPtr lParam);

        [DllImport("kernel32.dll")]
        private static extern IntPtr LoadLibrary(string lpFileName);

        [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
        private static extern bool FreeLibrary(IntPtr hModule);

        /// <summary>
        /// The SetWindowsHookEx function installs an application-defined hook procedure into a hook chain.
        /// You would install a hook procedure to monitor the system for certain types of events. These events are
        /// associated either with a specific thread or with all threads in the same desktop as the calling thread.
        /// </summary>
        /// <param name="idHook">hook type</param>
        /// <param name="lpfn">hook procedure</param>
        /// <param name="hMod">handle to application instance</param>
        /// <param name="dwThreadId">thread identifier</param>
        /// <returns>If the function succeeds, the return value is the handle to the hook procedure.</returns>
        [DllImport("USER32", SetLastError = true)]
        static extern IntPtr SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hMod, int dwThreadId);

        /// <summary>
        /// The UnhookWindowsHookEx function removes a hook procedure installed in a hook chain by the SetWindowsHookEx function.
        /// </summary>
        /// <param name="hhk">handle to hook procedure</param>
        /// <returns>If the function succeeds, the return value is true.</returns>
        [DllImport("USER32", SetLastError = true)]
        public static extern bool UnhookWindowsHookEx(IntPtr hHook);

        /// <summary>
        /// The CallNextHookEx function passes the hook information to the next hook procedure in the current hook chain.
        /// A hook procedure can call this function either before or after processing the hook information.
        /// </summary>
        /// <param name="hHook">handle to current hook</param>
        /// <param name="code">hook code passed to hook procedure</param>
        /// <param name="wParam">value passed to hook procedure</param>
        /// <param name="lParam">value passed to hook procedure</param>
        /// <returns>If the function succeeds, the return value is true.</returns>
        [DllImport("USER32", SetLastError = true)]
        static extern IntPtr CallNextHookEx(IntPtr hHook, int code, IntPtr wParam, IntPtr lParam);

        [StructLayout(LayoutKind.Sequential)]
        public struct LowLevelKeyboardInputEvent
        {
            /// <summary>
            /// A virtual-key code. The code must be a value in the range 1 to 254.
            /// </summary>
            public int VirtualCode;

            /// <summary>
            /// A hardware scan code for the key. 
            /// </summary>
            public int HardwareScanCode;

            /// <summary>
            /// The extended-key flag, event-injected Flags, context code, and transition-state flag. This member is specified as follows. An application can use the following values to test the keystroke Flags. Testing LLKHF_INJECTED (bit 4) will tell you whether the event was injected. If it was, then testing LLKHF_LOWER_IL_INJECTED (bit 1) will tell you whether or not the event was injected from a process running at lower integrity level.
            /// </summary>
            public int Flags;

            /// <summary>
            /// The time stamp stamp for this message, equivalent to what GetMessageTime would return for this message.
            /// </summary>
            public int TimeStamp;

            /// <summary>
            /// Additional information associated with the message. 
            /// </summary>
            public IntPtr AdditionalInformation;
        }

        public const int WH_KEYBOARD_LL = 13;
        //const int HC_ACTION = 0;

        public enum KeyboardState
        {
            KeyDown = 0x0100,
            KeyUp = 0x0101,
            SysKeyDown = 0x0104,
            SysKeyUp = 0x0105
        }

        public const int VkSnapshot = 0x2c;
        //const int VkLwin = 0x5b;
        //const int VkRwin = 0x5c;
        //const int VkTab = 0x09;
        //const int VkEscape = 0x18;
        //const int VkControl = 0x11;
        const int KfAltdown = 0x2000;
        public const int LlkhfAltdown = (KfAltdown >> 8);

        public IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam)
        {
            bool fEatKeyStroke = false;

            var wparamTyped = wParam.ToInt32();
            if (Enum.IsDefined(typeof(KeyboardState), wparamTyped))
            {
                object o = Marshal.PtrToStructure(lParam, typeof(LowLevelKeyboardInputEvent));
                LowLevelKeyboardInputEvent p = (LowLevelKeyboardInputEvent)o;

                var eventArguments = new GlobalKeyboardHookEventArgs(p, (KeyboardState)wparamTyped);

                EventHandler<GlobalKeyboardHookEventArgs> handler = KeyboardPressed;
                handler?.Invoke(this, eventArguments);

                fEatKeyStroke = eventArguments.Handled;
            }

            return fEatKeyStroke ? (IntPtr)1 : CallNextHookEx(IntPtr.Zero, nCode, wParam, lParam);
        }
    }
}

Usage:

using System;
using System.Windows.Forms;

namespace SnagFree.TrayApp.Core
{
    internal class Controller : IDisposable
    {
        private GlobalKeyboardHook _globalKeyboardHook;

        public void SetupKeyboardHooks()
        {
            _globalKeyboardHook = new GlobalKeyboardHook();
            _globalKeyboardHook.KeyboardPressed += OnKeyPressed;
        }

        private void OnKeyPressed(object sender, GlobalKeyboardHookEventArgs e)
        {
            //Debug.WriteLine(e.KeyboardData.VirtualCode);

            if (e.KeyboardData.VirtualCode != GlobalKeyboardHook.VkSnapshot)
                return;

            // seems, not needed in the life.
            //if (e.KeyboardState == GlobalKeyboardHook.KeyboardState.SysKeyDown &&
            //    e.KeyboardData.Flags == GlobalKeyboardHook.LlkhfAltdown)
            //{
            //    MessageBox.Show("Alt + Print Screen");
            //    e.Handled = true;
            //}
            //else

            if (e.KeyboardState == GlobalKeyboardHook.KeyboardState.KeyDown)
            {
                MessageBox.Show("Print Screen");
                e.Handled = true;
            }
        }

        public void Dispose()
        {
            _globalKeyboardHook?.Dispose();
        }
    }
}

Send email with PHPMailer - embed image in body

I found the answer:

$mail->AddEmbeddedImage('img/2u_cs_mini.jpg', 'logo_2u');

and on the <img> tag put src='cid:logo_2u'

What is the difference between exit and return?

  • return returns from the current function; it's a language keyword like for or break.
  • exit() terminates the whole program, wherever you call it from. (After flushing stdio buffers and so on).

The only case when both do (nearly) the same thing is in the main() function, as a return from main performs an exit().

In most C implementations, main is a real function called by some startup code that does something like int ret = main(argc, argv); exit(ret);. The C standard guarantees that something equivalent to this happens if main returns, however the implementation handles it.

Example with return:

#include <stdio.h>

void f(){
    printf("Executing f\n");
    return;
}

int main(){
    f();
    printf("Back from f\n");
}

If you execute this program it prints:

Executing f
Back from f

Another example for exit():

#include <stdio.h>
#include <stdlib.h>

void f(){
    printf("Executing f\n");
    exit(0);
}

int main(){
    f();
    printf("Back from f\n");
}

If you execute this program it prints:

Executing f

You never get "Back from f". Also notice the #include <stdlib.h> necessary to call the library function exit().

Also notice that the parameter of exit() is an integer (it's the return status of the process that the launcher process can get; the conventional usage is 0 for success or any other value for an error).

The parameter of the return statement is whatever the return type of the function is. If the function returns void, you can omit the return at the end of the function.

Last point, exit() come in two flavors _exit() and exit(). The difference between the forms is that exit() (and return from main) calls functions registered using atexit() or on_exit() before really terminating the process while _exit() (from #include <unistd.h>, or its synonymous _Exit from #include <stdlib.h>) terminates the process immediately.

Now there are also issues that are specific to C++.

C++ performs much more work than C when it is exiting from functions (return-ing). Specifically it calls destructors of local objects going out of scope. In most cases programmers won't care much of the state of a program after the processus stopped, hence it wouldn't make much difference: allocated memory will be freed, file ressource closed and so on. But it may matter if your destructor performs IOs. For instance automatic C++ OStream locally created won't be flushed on a call to exit and you may lose some unflushed data (on the other hand static OStream will be flushed).

This won't happen if you are using the good old C FILE* streams. These will be flushed on exit(). Actually, the rule is the same that for registered exit functions, FILE* will be flushed on all normal terminations, which includes exit(), but not calls to _exit() or abort().

You should also keep in mind that C++ provide a third way to get out of a function: throwing an exception. This way of going out of a function will call destructor. If it is not catched anywhere in the chain of callers, the exception can go up to the main() function and terminate the process.

Destructors of static C++ objects (globals) will be called if you call either return from main() or exit() anywhere in your program. They wont be called if the program is terminated using _exit() or abort(). abort() is mostly useful in debug mode with the purpose to immediately stop the program and get a stack trace (for post mortem analysis). It is usually hidden behind the assert() macro only active in debug mode.

When is exit() useful ?

exit() means you want to immediately stops the current process. It can be of some use for error management when we encounter some kind of irrecoverable issue that won't allow for your code to do anything useful anymore. It is often handy when the control flow is complicated and error codes has to be propagated all way up. But be aware that this is bad coding practice. Silently ending the process is in most case the worse behavior and actual error management should be preferred (or in C++ using exceptions).

Direct calls to exit() are especially bad if done in libraries as it will doom the library user and it should be a library user's choice to implement some kind of error recovery or not. If you want an example of why calling exit() from a library is bad, it leads for instance people to ask this question.

There is an undisputed legitimate use of exit() as the way to end a child process started by fork() on Operating Systems supporting it. Going back to the code before fork() is usually a bad idea. This is the rationale explaining why functions of the exec() family will never return to the caller.

Batch Script to Run as Administrator

As I have not found any simple script so far, here's my two cents:

set ELEVATE_APP=Full command line without parameters for the app to run
set ELEVATE_PARMS=The actual parameters for the app
echo Set objShell = CreateObject("Shell.Application") >elevatedapp.vbs
echo Set objWshShell = WScript.CreateObject("WScript.Shell") >>elevatedapp.vbs
echo Set objWshProcessEnv = objWshShell.Environment("PROCESS") >>elevatedapp.vbs
echo objShell.ShellExecute "%ELEVATE_APP%", "%ELEVATE_PARMS%", "", "runas" >>elevatedapp.vbs
DEL elevatedapp.vbs

How to grep a text file which contains some binary data?

You can force grep to look at binary files with:

grep --binary-files=text

You might also want to add -o (--only-matching) so you don't get tons of binary gibberish that will bork your terminal.

JPanel setBackground(Color.BLACK) does nothing

setOpaque(false); 

CHANGED to

setOpaque(true);

Rails: Check output of path helper from console

Remember if your route is name-spaced, Like:

product GET  /products/:id(.:format)  spree/products#show

Then try :

helper.link_to("test", app.spree.product_path(Spree::Product.first), method: :get)

output

Spree::Product Load (0.4ms)  SELECT  "spree_products".* FROM "spree_products"  WHERE "spree_products"."deleted_at" IS NULL  ORDER BY "spree_products"."id" ASC LIMIT 1
=> "<a data-method=\"get\" href=\"/products/this-is-the-title\">test</a>" 

crop text too long inside div

Why not use relative units?

.cropText {
    max-width: 20em;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

jQuery object equality

Since jQuery 1.6, you can use .is. Below is the answer from over a year ago...

var a = $('#foo');
var b = a;


if (a.is(b)) {
    // the same object!
}

If you want to see if two variables are actually the same object, eg:

var a = $('#foo');
var b = a;

...then you can check their unique IDs. Every time you create a new jQuery object it gets an id.

if ($.data(a) == $.data(b)) {
    // the same object!
}

Though, the same could be achieved with a simple a === b, the above might at least show the next developer exactly what you're testing for.

In any case, that's probably not what you're after. If you wanted to check if two different jQuery objects contain the same set of elements, the you could use this:

$.fn.equals = function(compareTo) {
  if (!compareTo || this.length != compareTo.length) {
    return false;
  }
  for (var i = 0; i < this.length; ++i) {
    if (this[i] !== compareTo[i]) {
      return false;
    }
  }
  return true;
};

Source

var a = $('p');
var b = $('p');
if (a.equals(b)) {
    // same set
}

SSRS expression to format two decimal places does not show zeros

If you want to always display some value after decimal for example "12.00" or "12.23" Then use just like below , it worked for me

FormatNumber("145.231000",2) Which will display 145.23

FormatNumber("145",2) Which will display 145.00

Placing a textview on top of imageview in android

As you mentioned in OP, you need to overlay Text on ImageView programmatically way. You can get ImageView drawable and write on it with the help of putting it on Canvas and Paint.

 private BitmapDrawable writeTextOnDrawable(int drawableId, String text) 
 {
 Bitmap bm = BitmapFactory.decodeResource(getResources(), drawableId).copy(Bitmap.Config.ARGB_8888, true);
 Typeface tf = Typeface.create("Helvetica", Typeface.BOLD);
 Paint paint = new Paint();
 paint.setStyle(Style.FILL);
 paint.setColor(Color.WHITE);
 paint.setTypeface(tf);
 paint.setTextAlign(Align.CENTER);
 paint.setTextSize(11);
 Rect textRect = new Rect();
 paint.getTextBounds(text, 0, text.length(), textRect);
 Canvas canvas = new Canvas(bm);
 canvas.drawText(text, xPos, yPos, paint);
 return new BitmapDrawable(getResources(), bm);
 }

Java Code for calculating Leap Year

java.time.Year::isLeap

I'd like to add the new java.time way of doing this with the Year class and isLeap method:

java.time.Year.of(year).isLeap();

Comparing Arrays of Objects in JavaScript

EDIT: You cannot overload operators in current, common browser-based implementations of JavaScript interpreters.

To answer the original question, one way you could do this, and mind you, this is a bit of a hack, simply serialize the two arrays to JSON and then compare the two JSON strings. That would simply tell you if the arrays are different, obviously you could do this to each of the objects within the arrays as well to see which ones were different.

Another option is to use a library which has some nice facilities for comparing objects - I use and recommend MochiKit.


EDIT: The answer kamens gave deserves consideration as well, since a single function to compare two given objects would be much smaller than any library to do what I suggest (although my suggestion would certainly work well enough).

Here is a naïve implemenation that may do just enough for you - be aware that there are potential problems with this implementation:

function objectsAreSame(x, y) {
   var objectsAreSame = true;
   for(var propertyName in x) {
      if(x[propertyName] !== y[propertyName]) {
         objectsAreSame = false;
         break;
      }
   }
   return objectsAreSame;
}

The assumption is that both objects have the same exact list of properties.

Oh, and it is probably obvious that, for better or worse, I belong to the only-one-return-point camp. :)

Creating a constant Dictionary in C#

If using 4.5+ Framework I would use ReadOnlyDictionary (also ReadOnly Collection for lists) to do readonly mappings/constants. It's implemented in the following way.

static class SomeClass
{
    static readonly ReadOnlyDictionary<string,int> SOME_MAPPING 
        = new ReadOnlyDictionary<string,int>(
            new Dictionary<string,int>()
            {
                { "One", 1 },
                { "Two", 2 }
            }
        )
}        

Loading basic HTML in Node.js

try this one:

var http = require('http');
var fs = require('fs');
var PORT = 8080;

http.createServer((req, res) => {
    fs.readFile('./' + req.url, (err, data) => {
        if (!err) {
            var dotoffset = req.url.lastIndexOf('.');
            var mimetype = dotoffset == -1 ? 'text/plaint' : {
                '.html': 'text/html',
                '.css': 'text/css',
                '.js': 'text/javascript',
                '.jpg': 'image/jpeg',
                '.png': 'image/png',
                '.ico': 'image/x-icon',
                '.gif': 'image/gif'
            }[ req.url.substr(dotoffset) ];
            res.setHeader('Content-Type', mimetype);
            res.end(data);
            console.log(req.url, mimetype);
        } else {
            console.log('File not fount: ' + req.url);
            res.writeHead(404, "Not Found");
            res.end();
        }
    });
 }).listen(PORT);

With this, you can include js, css source-codes when linking them and you can load icons, imgs, gifs. And if you want, you can add more if you need.

Replace invalid values with None in Pandas DataFrame

df.replace('-', np.nan).astype("object")

This will ensure that you can use isnull() later on your dataframe

Using StringWriter for XML Serialization

It may have been covered elsewhere but simply changing the encoding line of the XML source to 'utf-16' allows the XML to be inserted into a SQL Server 'xml'data type.

using (DataSetTableAdapters.SQSTableAdapter tbl_SQS = new DataSetTableAdapters.SQSTableAdapter())
{
    try
    {
        bodyXML = @"<?xml version="1.0" encoding="UTF-8" standalone="yes"?><test></test>";
        bodyXMLutf16 = bodyXML.Replace("UTF-8", "UTF-16");
        tbl_SQS.Insert(messageID, receiptHandle, md5OfBody, bodyXMLutf16, sourceType);
    }
    catch (System.Data.SqlClient.SqlException ex)
    {
        Console.WriteLine(ex.Message);
        Console.ReadLine();
    }
}

The result is all of the XML text is inserted into the 'xml' data type field but the 'header' line is removed. What you see in the resulting record is just

<test></test>

Using the serialization method described in the "Answered" entry is a way of including the original header in the target field but the result is that the remaining XML text is enclosed in an XML <string></string> tag.

The table adapter in the code is a class automatically built using the Visual Studio 2013 "Add New Data Source: wizard. The five parameters to the Insert method map to fields in a SQL Server table.

How to get list of all installed packages along with version in composer?

If you only want to check version for only one, you can do

composer show -- twig/twig

Note that only installed packages are shown by default now, and installed option is now deprecated.

Reading numbers from a text file into an array in C

for (i = 0; i < 16; i++)
{
    fscanf(myFile, "%d", &numberArray[i]);
}

This is attempting to read the whole string, "5623125698541159" into &numArray[0]. You need spaces between the numbers:

5 6 2 3 ...

Error handling in AngularJS http get then construct

You need to add an additional parameter:

$http.get(url).then(
    function(response) {
        console.log('get',response)
    },
    function(data) {
        // Handle error here
    })

Javascript window.open pass values using POST

The code helped me to fulfill my requirement.

I have made some modifications and using a form I completed this. Here is my code-

Need a 'target' attribute for 'form' -- that's it!

Form

<form id="view_form" name="view_form" method="post" action="view_report.php"  target="Map" >
  <input type="text" value="<?php echo $sale->myvalue1; ?>" name="my_value1"/>
  <input type="text" value="<?php echo $sale->myvalue2; ?>" name="my_value2"/>
  <input type="button" id="download" name="download" value="View report" onclick="view_my_report();"   /> 
</form>

JavaScript

function view_my_report() {     
   var mapForm = document.getElementById("view_form");
   map=window.open("","Map","status=0,title=0,height=600,width=800,scrollbars=1");

   if (map) {
      mapForm.submit();
   } else {
      alert('You must allow popups for this map to work.');
   }
}

Full code is explained showing normal form and form elements.

Error Domain=NSURLErrorDomain Code=-1005 "The network connection was lost."

Whenever got error -1005 then need to call API Again.

AFHTTPRequestOperationManager *manager = 
[AFHTTPRequestOperationManager manager];
[manager setSecurityPolicy:policy];
manager.requestSerializer = [AFHTTPRequestSerializer serializer];
manager.responseSerializer = [AFHTTPResponseSerializer serializer];

[manager POST:<example-url>
   parameters:<parameteres>
    success:^(AFHTTPRequestOperation *operation, id responseObject) {
      NSLog(@“Success: %@", responseObject);
  } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
      NSLog(@"Error: %@", error);
      if (error.code == -1005) {
          // Call method again... 
       }
  }];

You need to Add your code to call function again. MakeSure that you were call method once otherwise its call recursive loop.

How to update Xcode from command line

xCode version 11.2.1 is necessary for building app in iPad 13.2.3, When I directly try to upgrade from xcode 11.1 to 11.2.1 through App Store it get struck, So after some research , I found a solution to upgrade by removing the existing xcode from the system

So here I am adding the steps to upgrade after uninstalling existing xcode.

  1. Go to Applications and identify Xcode and drag it to trash.
  2. Empty trash to permenently delete Xcode.
  3. Now go to ~/Library/Developer/ folder and remove the contents completely Use sudo rm -rf ~/Library/Developer/ to avoid any permission issue while deleting
  4. Lastly remove any cache directory associated with xcode in the path ~/Library/Caches/com.apple.dt.Xcode sudo rm -rf ~/Library/Caches/com.apple.dt.Xcode/*
  5. After completing the above steps you can easly install xcode from App Store, which will install the current latest version of xcode

Note: Please take a backup of your existing projects before making the above changes

center image in div with overflow hidden

For me flex-box worked perfect to center the image.

this is my html-code:

<div class="img-wrapper">
  <img src="..." >
</div>

and this i used for css: I wanted the Image same wide as the wrapper-element, but if the height is greater than the height of the wrapper-element it should be "cropped"/not displayed.

.img-wrapper{
  width: 100%;
  height: 50%;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center; 
}
img {
  height: auto;
  width: 100%;
}

Structs in Javascript

I always use object literals

{id: 1, speaker:"john", country: "au"}

Routing for custom ASP.NET MVC 404 Error page

I will talk about some specific cases,

if you are using 'PageNotFound method' in HomeController like below

[Route("~/404")]
public ActionResult PageNotFound()
{
  return MyView();
}

it wouldn't work this. But you must clear Route tags like below,

//[Route("~/404")]
public ActionResult PageNotFound()
{
  return MyView();
}

And if you change it as method Name in web.config it works. However don't forget to do code like below in web.config

<customErrors mode="On">
  <error statusCode="404" redirect="~/PageNotFound" /> 
 *// it is not "~/404" because it is not accepted url in Route Tag like [Route("404")]*
</customErrors>

How to create a secure random AES key in Java?

I would use your suggested code, but with a slight simplification:

KeyGenerator keyGen = KeyGenerator.getInstance("AES");
keyGen.init(256); // for example
SecretKey secretKey = keyGen.generateKey();

Let the provider select how it plans to obtain randomness - don't define something that may not be as good as what the provider has already selected.

This code example assumes (as Maarten points out below) that you've configured your java.security file to include your preferred provider at the top of the list. If you want to manually specify the provider, just call KeyGenerator.getInstance("AES", "providerName");.

For a truly secure key, you need to be using a hardware security module (HSM) to generate and protect the key. HSM manufacturers will typically supply a JCE provider that will do all the key generation for you, using the code above.

OrderBy pipe issue

Please see https://angular.io/guide/pipes#appendix-no-filterpipe-or-orderbypipe for the full discussion. This quote is most relevant. Basically, for large scale apps that should be minified aggressively the filtering and sorting logic should move to the component itself.

"Some of us may not care to minify this aggressively. That's our choice. But the Angular product should not prevent someone else from minifying aggressively. Therefore, the Angular team decided that everything shipped in Angular will minify safely.

The Angular team and many experienced Angular developers strongly recommend that you move filtering and sorting logic into the component itself. The component can expose a filteredHeroes or sortedHeroes property and take control over when and how often to execute the supporting logic. Any capabilities that you would have put in a pipe and shared across the app can be written in a filtering/sorting service and injected into the component."

How to copy a string of std::string type in C++?

strcpy is only for C strings. For std::string you copy it like any C++ object.

std::string a = "text";
std::string b = a; // copy a into b

If you want to concatenate strings you can use the + operator:

std::string a = "text";
std::string b = "image";
a = a + b; // or a += b;

You can even do many at once:

std::string c = a + " " + b + "hello";

Although "hello" + " world" doesn't work as you might expect. You need an explicit std::string to be in there: std::string("Hello") + "world"

Python - TypeError: 'int' object is not iterable

If the case is:

n=int(input())

Instead of -> for i in n: -> gives error- 'int' object is not iterable

Use -> for i in range(0,n): -> works fine..!

Exception thrown inside catch block - will it be caught again?

The Java Language Specification says in section 14.19.1:

If execution of the try block completes abruptly because of a throw of a value V, then there is a choice:

  • If the run-time type of V is assignable to the Parameter of any catch clause of the try statement, then the first (leftmost) such catch clause is selected. The value V is assigned to the parameter of the selected catch clause, and the Block of that catch clause is executed. If that block completes normally, then the try statement completes normally; if that block completes abruptly for any reason, then the try statement completes abruptly for the same reason.

Reference: http://java.sun.com/docs/books/jls/second_edition/html/statements.doc.html#24134

In other words, the first enclosing catch that can handle the exception does, and if an exception is thrown out of that catch, that's not in the scope of any other catch for the original try, so they will not try to handle it.

One related and confusing thing to know is that in a try-[catch]-finally structure, a finally block may throw an exception and if so, any exception thrown by the try or catch block is lost. That can be confusing the first time you see it.

DateTime2 vs DateTime in SQL Server

I concurr with @marc_s and @Adam_Poward -- DateTime2 is the preferred method moving forward. It has a wider range of dates, higher precision, and uses equal or less storage (depending on precision).

One thing the discussion missed, however...
@Marc_s states: Both types map to System.DateTime in .NET - no difference there. This is correct, however, the inverse is not true...and it matters when doing date range searches (e.g. "find me all records modified on 5/5/2010").

.NET's version of Datetime has similar range and precision to DateTime2. When mapping a .net Datetime down to the old SQL DateTime an implicit rounding occurs. The old SQL DateTime is accurate to 3 milliseconds. This means that 11:59:59.997 is as close as you can get to the end of the day. Anything higher is rounded up to the following day.

Try this :

declare @d1 datetime   = '5/5/2010 23:59:59.999'
declare @d2 datetime2  = '5/5/2010 23:59:59.999'
declare @d3 datetime   = '5/5/2010 23:59:59.997'
select @d1 as 'IAmMay6BecauseOfRounding', @d2 'May5', @d3 'StillMay5Because2msEarlier'

Avoiding this implicit rounding is a significant reason to move to DateTime2. Implicit rounding of dates clearly causes confusion:

WCF Service Client: The content type text/html; charset=utf-8 of the response message does not match the content type of the binding

As with many, in my situation I was also getting this because of an error. And sadly I could just read the CSS of the html error page.

The source of my problem was also a rewrite rule on the server. It was rewriting http to https.

What is the unix command to see how much disk space there is and how much is remaining?

su -sm ./*

You can see every file and folder size (-sm=Mb ; -sk=Kb) in the current directory like a list. This way runs in all Unix/Linux environment.

Update date + one year in mysql

You could use DATE_ADD : (or ADDDATE with INTERVAL)

UPDATE table SET date = DATE_ADD(date, INTERVAL 1 YEAR) 

Access IP Camera in Python OpenCV

In pycharm I wrote the code for accessing the IP Camera like:

import cv2

cap=VideoCapture("rtsp://user_name:password@IP_address:port_number")

ret, frame=cap.read()

You will need to replace user_name, password, IP and port with suitable values

How can I go back/route-back on vue-router?

If you're using Vuex you can use https://github.com/vuejs/vuex-router-sync

Just initialize it in your main file with:

import VuexRouterSync from 'vuex-router-sync';
VuexRouterSync.sync(store, router);

Each route change will update route state object in Vuex. You can next create getter to use the from Object in route state or just use the state (better is to use getters, but it's other story https://vuex.vuejs.org/en/getters.html), so in short it would be (inside components methods/values):

this.$store.state.route.from.fullPath

You can also just place it in <router-link> component:

<router-link :to="{ path: $store.state.route.from.fullPath }"> 
  Back 
</router-link>

So when you use code above, link to previous path would be dynamically generated.

Display two fields side by side in a Bootstrap Form

did you check boostrap website? search for "forms"

<div class="form-row">
<div class="col">
  <input type="text" class="form-control" placeholder="First name">
</div>
<div class="col">
  <input type="text" class="form-control" placeholder="Last name">
</div>

How to export data as CSV format from SQL Server using sqlcmd?

This answer builds on the solution from @iain-elder, which works well except for the large database case (as pointed out in his solution). The entire table needs to fit in your system's memory, and for me this was not an option. I suspect the best solution would use the System.Data.SqlClient.SqlDataReader and a custom CSV serializer (see here for an example) or another language with an MS SQL driver and CSV serialization. In the spirit of the original question which was probably looking for a no dependency solution, the PowerShell code below worked for me. It is very slow and inefficient especially in instantiating the $data array and calling Export-Csv in append mode for every $chunk_size lines.

$chunk_size = 10000
$command = New-Object System.Data.SqlClient.SqlCommand
$command.CommandText = "SELECT * FROM <TABLENAME>"
$command.Connection = $connection
$connection.open()
$reader = $command.ExecuteReader()

$read = $TRUE
while($read){
    $counter=0
    $DataTable = New-Object System.Data.DataTable
    $first=$TRUE;
    try {
        while($read = $reader.Read()){

            $count = $reader.FieldCount
            if ($first){
                for($i=0; $i -lt $count; $i++){
                    $col = New-Object System.Data.DataColumn $reader.GetName($i)
                    $DataTable.Columns.Add($col)
                }
                $first=$FALSE;
            }

            # Better way to do this?
            $data=@()
            $emptyObj = New-Object System.Object
            for($i=1; $i -le $count; $i++){
                $data +=  $emptyObj
            }

            $reader.GetValues($data) | out-null
            $DataRow = $DataTable.NewRow()
            $DataRow.ItemArray = $data
            $DataTable.Rows.Add($DataRow)
            $counter += 1
            if ($counter -eq $chunk_size){
                break
            }
        }
        $DataTable | Export-Csv "output.csv" -NoTypeInformation -Append
    }catch{
        $ErrorMessage = $_.Exception.Message
        Write-Output $ErrorMessage
        $read=$FALSE
        $connection.Close()
        exit
    }
}
$connection.close()

AccessDenied for ListObjects for S3 bucket when permissions are s3:*

You have given permission to perform commands on objects inside the S3 bucket, but you have not given permission to perform any actions on the bucket itself.

Slightly modifying your policy would look like this:

{
  "Version": "version_id",
  "Statement": [
    {
        "Sid": "some_id",
        "Effect": "Allow",
        "Action": [
            "s3:*"
        ],
        "Resource": [
            "arn:aws:s3:::bucketname",
            "arn:aws:s3:::bucketname/*"
        ]
    }
  ] 
}

However, that probably gives more permission than is needed. Following the AWS IAM best practice of Granting Least Privilege would look something like this:

{
  "Version": "2012-10-17",
  "Statement": [
      {
          "Effect": "Allow",
          "Action": [
              "s3:ListBucket"
          ],
          "Resource": [
              "arn:aws:s3:::bucketname"
          ]
      },
      {
          "Effect": "Allow",
          "Action": [
              "s3:GetObject"
          ],
          "Resource": [
              "arn:aws:s3:::bucketname/*"
          ]
      }
  ]
}

Using Predicate in Swift

Working with predicate for pretty long time. Here is my conclusion (SWIFT)

//Customizable! (for me was just important if at least one)
request.fetchLimit = 1


//IF IS EQUAL

//1 OBJECT
request.predicate = NSPredicate(format: "name = %@", txtFieldName.text)

//ARRAY
request.predicate = NSPredicate(format: "name = %@ AND nickName = %@", argumentArray: [name, nickname])


// IF CONTAINS

//1 OBJECT
request.predicate = NSPredicate(format: "name contains[c] %@", txtFieldName.text)

//ARRAY
request.predicate = NSPredicate(format: "name contains[c] %@ AND nickName contains[c] %@", argumentArray: [name, nickname])