Programs & Examples On #Oolong

Best way to resolve file path too long exception

Not mention so far and an update, there is a very well establish library for handling paths that are too long. AlphaFS is a .NET library providing more complete Win32 file system functionality to the .NET platform than the standard System.IO classes. The most notable deficiency of the standard .NET System.IO is the lack of support of advanced NTFS features, most notably extended length path support (eg. file/directory paths longer than 260 characters).

CSS3 selector :first-of-type with class name?

Simply :first works for me, why isn't this mentioned yet?

If input field is empty, disable submit button

For those that use coffeescript, I've put the code we use globally to disable the submit buttons on our most widely used form. An adaption of Adil's answer above.

$('#new_post button').prop 'disabled', true
$('#new_post #post_message').keyup ->
    $('#new_post button').prop 'disabled', if @value == '' then true else false
    return

Visual Studio: How to show Overloads in IntelliSense?

  • The command Edit.ParameterInfo (mapped to Ctrl+Shift+Space by default) will show the overload tooltip if it's invoked when the cursor is inside the parameter brackets of a method call.

  • The command Edit.QuickInfo (mapped to Ctrl+KCtrl+I by default) will show the tooltip that you'd see if you moused over the cursor location.

How to create and download a csv file from php script?

Try... csv download.

<?php 
mysql_connect('hostname', 'username', 'password');
mysql_select_db('dbname');
$qry = mysql_query("SELECT * FROM tablename");
$data = "";
while($row = mysql_fetch_array($qry)) {
  $data .= $row['field1'].",".$row['field2'].",".$row['field3'].",".$row['field4']."\n";
}

header('Content-Type: application/csv');
header('Content-Disposition: attachment; filename="filename.csv"');
echo $data; exit();
?>

Reactjs - Form input validation

import React from 'react';
import {sendFormData} from '../services/';

class Signup extends React.Component{
  constructor(props){
    super(props);
     this.state = {
       isDisabled:true
     }                                                                                                 
     this.submitForm = this.submitForm.bind(this);
  }
  validateEmail(email){
   const pattern = /[a-zA-Z0-9]+[\.]?([a-zA-Z0-9]+)?[\@][a-z]{3,9}[\.][a-z]{2,5}/g;
   const result = pattern.test(email);
   if(result===true){
     this.setState({
       emailError:false,
       email:email
     })
   } else{
     this.setState({
       emailError:true
     })
   }
 }
 handleChange(e){
  const target = e.target;
  const value = target.type === 'checkbox' ? target.checked : target.value;
  const name = target.name;
  this.setState({
    [name]: value
  });
  if(e.target.name==='firstname'){
    if(e.target.value==='' || e.target.value===null ){
      this.setState({
        firstnameError:true
      })
    } else {
      this.setState({
        firstnameError:false,     
        firstName:e.target.value
      })
    }
  }
  if(e.target.name==='lastname'){
    if(e.target.value==='' || e.target.value===null){
      this.setState({
        lastnameError:true
      })
    } else {
      this.setState({
        lastnameError:false,
        lastName:e.target.value
      })
    }
  }
  if(e.target.name==='email'){
   this.validateEmail(e.target.value);
  }
  if(e.target.name==='password'){
    if(e.target.value==='' || e.target.value===null){
      this.setState({
        passwordError:true
      })
    } else {
      this.setState({
        passwordError:false,
        password:e.target.value
      })
    }
 }
 if(this.state.firstnameError===false && this.state.lastnameError===false && 
  this.state.emailError===false && this.state.passwordError===false){
    this.setState({
      isDisabled:false
    })
 }
}
submitForm(e){
  e.preventDefault();
  const data = {
   firstName: this.state.firstName,
   lastName: this.state.lastName,
   email: this.state.email,
   password: this.state.password
  }
  sendFormData(data).then(res=>{
    if(res.status===200){
      alert(res.data);
      this.props.history.push('/');
    }else{

    } 
  });
 }
render(){
return(
  <div className="container">
    <div className="card card-login mx-auto mt-5">
      <div className="card-header">Register here</div>
        <div className="card-body">
            <form id="signup-form">
              <div className="form-group">
                <div className="form-label-group">
                  <input type="text" id="firstname" name="firstname" className="form-control" placeholder="Enter firstname" onChange={(e)=>{this.handleChange(e)}} />
                  <label htmlFor="firstname">firstname</label>
                  {this.state.firstnameError ? <span style={{color: "red"}}>Please Enter some value</span> : ''} 
                </div>
              </div>
              <div className="form-group">
                <div className="form-label-group">
                  <input type="text" id="lastname" name="lastname" className="form-control" placeholder="Enter lastname" onChange={(e)=>{this.handleChange(e)}} />
                  <label htmlFor="lastname">lastname</label>
                  {this.state.lastnameError ? <span style={{color: "red"}}>Please Enter some value</span> : ''}
                </div>
              </div>
              <div className="form-group">
                <div className="form-label-group">
                  <input type="email" id="email" name="email" className="form-control" placeholder="Enter your email" onChange={(e)=>{this.handleChange(e)}} />
                  <label htmlFor="email">email</label>
                  {this.state.emailError ? <span style={{color: "red"}}>Please Enter valid email address</span> : ''}
                </div>
              </div>                
              <div className="form-group">
                <div className="form-label-group">
                  <input type="password" id="password" name="password" className="form-control" placeholder="Password" onChange={(e)=>{this.handleChange(e)}} />
                  <label htmlFor="password">Password</label>
                  {this.state.passwordError ? <span style={{color: "red"}}>Please enter some   value</span> : ''}
                </div>
              </div>                
              <button className="btn btn-primary btn-block" disabled={this.state.isDisabled} onClick={this.submitForm}>Signup</button>
            </form>
        </div>
      </div>
    </div>
  );
 }
}
export default Signup;

How to read embedded resource text file

By all your powers combined I use this helper class for reading resources from any assembly and any namespace in a generic way.

public class ResourceReader
{
    public static IEnumerable<string> FindEmbededResources<TAssembly>(Func<string, bool> predicate)
    {
        if (predicate == null) throw new ArgumentNullException(nameof(predicate));

        return
            GetEmbededResourceNames<TAssembly>()
                .Where(predicate)
                .Select(name => ReadEmbededResource(typeof(TAssembly), name))
                .Where(x => !string.IsNullOrEmpty(x));
    }

    public static IEnumerable<string> GetEmbededResourceNames<TAssembly>()
    {
        var assembly = Assembly.GetAssembly(typeof(TAssembly));
        return assembly.GetManifestResourceNames();
    }

    public static string ReadEmbededResource<TAssembly, TNamespace>(string name)
    {
        if (string.IsNullOrEmpty(name)) throw new ArgumentNullException(nameof(name));
        return ReadEmbededResource(typeof(TAssembly), typeof(TNamespace), name);
    }

    public static string ReadEmbededResource(Type assemblyType, Type namespaceType, string name)
    {
        if (assemblyType == null) throw new ArgumentNullException(nameof(assemblyType));
        if (namespaceType == null) throw new ArgumentNullException(nameof(namespaceType));
        if (string.IsNullOrEmpty(name)) throw new ArgumentNullException(nameof(name));

        return ReadEmbededResource(assemblyType, $"{namespaceType.Namespace}.{name}");
    }

    public static string ReadEmbededResource(Type assemblyType, string name)
    {
        if (assemblyType == null) throw new ArgumentNullException(nameof(assemblyType));
        if (string.IsNullOrEmpty(name)) throw new ArgumentNullException(nameof(name));

        var assembly = Assembly.GetAssembly(assemblyType);
        using (var resourceStream = assembly.GetManifestResourceStream(name))
        {
            if (resourceStream == null) return null;
            using (var streamReader = new StreamReader(resourceStream))
            {
                return streamReader.ReadToEnd();
            }
        }
    }
}

What is the best data type to use for money in C#?

Another option (especially if you're rolling you own class) is to use an int or a int64, and designate the lower four digits (or possibly even 2) as "right of the decimal point". So "on the edges" you'll need some "* 10000" on the way in and some "/ 10000" on the way out. This is the storage mechanism used by Microsoft's SQL Server, see http://msdn.microsoft.com/en-au/library/ms179882.aspx

The nicity of this is that all your summation can be done using (fast) integer arithmetic.

ASP.NET Identity's default Password Hasher - How does it work and is it secure?

For those like me who are brand new to this, here is code with const and an actual way to compare the byte[]'s. I got all of this code from stackoverflow but defined consts so values could be changed and also

// 24 = 192 bits
    private const int SaltByteSize = 24;
    private const int HashByteSize = 24;
    private const int HasingIterationsCount = 10101;


    public static string HashPassword(string password)
    {
        // http://stackoverflow.com/questions/19957176/asp-net-identity-password-hashing

        byte[] salt;
        byte[] buffer2;
        if (password == null)
        {
            throw new ArgumentNullException("password");
        }
        using (Rfc2898DeriveBytes bytes = new Rfc2898DeriveBytes(password, SaltByteSize, HasingIterationsCount))
        {
            salt = bytes.Salt;
            buffer2 = bytes.GetBytes(HashByteSize);
        }
        byte[] dst = new byte[(SaltByteSize + HashByteSize) + 1];
        Buffer.BlockCopy(salt, 0, dst, 1, SaltByteSize);
        Buffer.BlockCopy(buffer2, 0, dst, SaltByteSize + 1, HashByteSize);
        return Convert.ToBase64String(dst);
    }

    public static bool VerifyHashedPassword(string hashedPassword, string password)
    {
        byte[] _passwordHashBytes;

        int _arrayLen = (SaltByteSize + HashByteSize) + 1;

        if (hashedPassword == null)
        {
            return false;
        }

        if (password == null)
        {
            throw new ArgumentNullException("password");
        }

        byte[] src = Convert.FromBase64String(hashedPassword);

        if ((src.Length != _arrayLen) || (src[0] != 0))
        {
            return false;
        }

        byte[] _currentSaltBytes = new byte[SaltByteSize];
        Buffer.BlockCopy(src, 1, _currentSaltBytes, 0, SaltByteSize);

        byte[] _currentHashBytes = new byte[HashByteSize];
        Buffer.BlockCopy(src, SaltByteSize + 1, _currentHashBytes, 0, HashByteSize);

        using (Rfc2898DeriveBytes bytes = new Rfc2898DeriveBytes(password, _currentSaltBytes, HasingIterationsCount))
        {
            _passwordHashBytes = bytes.GetBytes(SaltByteSize);
        }

        return AreHashesEqual(_currentHashBytes, _passwordHashBytes);

    }

    private static bool AreHashesEqual(byte[] firstHash, byte[] secondHash)
    {
        int _minHashLength = firstHash.Length <= secondHash.Length ? firstHash.Length : secondHash.Length;
        var xor = firstHash.Length ^ secondHash.Length;
        for (int i = 0; i < _minHashLength; i++)
            xor |= firstHash[i] ^ secondHash[i];
        return 0 == xor;
    }

In in your custom ApplicationUserManager, you set the PasswordHasher property the name of the class which contains the above code.

positional argument follows keyword argument

The grammar of the language specifies that positional arguments appear before keyword or starred arguments in calls:

argument_list        ::=  positional_arguments ["," starred_and_keywords]
                            ["," keywords_arguments]
                          | starred_and_keywords ["," keywords_arguments]
                          | keywords_arguments

Specifically, a keyword argument looks like this: tag='insider trading!' while a positional argument looks like this: ..., exchange, .... The problem lies in that you appear to have copy/pasted the parameter list, and left some of the default values in place, which makes them look like keyword arguments rather than positional ones. This is fine, except that you then go back to using positional arguments, which is a syntax error.

Also, when an argument has a default value, such as price=None, that means you don't have to provide it. If you don't provide it, it will use the default value instead.

To resolve this error, convert your later positional arguments into keyword arguments, or, if they have default values and you don't need to use them, simply don't specify them at all:

order_id = kite.order_place(self, exchange, tradingsymbol,
    transaction_type, quantity)

# Fully positional:
order_id = kite.order_place(self, exchange, tradingsymbol, transaction_type, quantity, price, product, order_type, validity, disclosed_quantity, trigger_price, squareoff_value, stoploss_value, trailing_stoploss, variety, tag)

# Some positional, some keyword (all keywords at end):

order_id = kite.order_place(self, exchange, tradingsymbol,
    transaction_type, quantity, tag='insider trading!')

Format a BigDecimal as String with max 2 decimal digits, removing 0 on decimal part

The below code may help you.

protected String getLocalizedBigDecimalValue(BigDecimal input, Locale locale) {
    final NumberFormat numberFormat = NumberFormat.getNumberInstance(locale);
    numberFormat.setGroupingUsed(true);
    numberFormat.setMaximumFractionDigits(2);
    numberFormat.setMinimumFractionDigits(2);
    return numberFormat.format(input);
}

Bash script to cd to directory with spaces in pathname

use double quotes

go () 
{ 
    cd "$*"
}

sql: check if entry in table A exists in table B

Or if "NOT EXISTS" are not implemented

SELECT *
FROM   B
WHERE (SELECT count(*)  FROM   A WHERE  A.ID = B.ID) < 1

Improve INSERT-per-second performance of SQLite

I coudn't get any gain from transactions until I raised cache_size to a higher value i.e. PRAGMA cache_size=10000;

laravel 5.3 new Auth::routes()

For Laravel 5.5.x

// Authentication Routes...
$this->get('login', 'Auth\LoginController@showLoginForm')->name('login');
$this->post('login', 'Auth\LoginController@login');
$this->post('logout', 'Auth\LoginController@logout')->name('logout');

// Registration Routes...
$this->get('register', 'Auth\RegisterController@showRegistrationForm')->name('register');
$this->post('register', 'Auth\RegisterController@register');

// Password Reset Routes...
$this->get('password/reset', 'Auth\ForgotPasswordController@showLinkRequestForm')->name('password.request');
$this->post('password/email', 'Auth\ForgotPasswordController@sendResetLinkEmail')->name('password.email');
$this->get('password/reset/{token}', 'Auth\ResetPasswordController@showResetForm')->name('password.reset');
$this->post('password/reset', 'Auth\ResetPasswordController@reset');

Check if a JavaScript string is a URL

I change the function to Match + make a change here with the slashes and its work: (http:// and https) both

function isValidUrl(userInput) {
    var res = userInput.match(/(http(s)?:\/\/.)?(www\.)?[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[a-z]{2,6}\b([-a-zA-Z0-9@:%_\+.~#?&//=]*)/g);
    if(res == null)
       return false;
    else
       return true;
}

"Insufficient Storage Available" even there is lot of free space in device memory

The first thing to do is to check the details of the error message. For this you could use the LogCat App.

For me the problem was an error like

Cannot rename native library directory /data/app-lib/vmdl-... to /data/app-lib/com.xyz

The solution was to activate the common sense function in my brain and look for the com.xyz folder in the app-lib folder with ES-Explorer. I recognized that this folder was already there. So removing it solved the renaming problem and the apps can now install properly.

Find a file with a certain extension in folder

Use this code for read file with all type of extension file.

string[] sDirectoryInfo = Directory.GetFiles(SourcePath, "*.*");

Call Activity method from adapter

In Kotlin there is now a cleaner way by using lambda functions, no need for interfaces:

class MyAdapter(val adapterOnClick: (Any) -> Unit) {
    fun setItem(item: Any) {
        myButton.setOnClickListener { adapterOnClick(item) }
    }
}

class MyActivity {
    override fun onCreate(savedInstanceState: Bundle?) {
        var myAdapter = MyAdapter { item -> doOnClick(item) }
    }


    fun doOnClick(item: Any) {

    }
}

How find out which process is using a file in Linux?

You can use the fuser command, like:

fuser file_name

You will receive a list of processes using the file.

You can use different flags with it, in order to receive a more detailed output.

You can find more info in the fuser's Wikipedia article, or in the man pages.

Wpf DataGrid Add new row

Just simply use this Style of DataGridRow:

<DataGrid.RowStyle>
        <Style TargetType="DataGridRow">
            <Setter Property="IsEnabled" Value="{Binding RelativeSource={RelativeSource Self},Path=IsNewItem,Mode=OneWay}" />
        </Style>
</DataGrid.RowStyle>

Can constructors be async?

Some of the answers involve creating a new public method. Without doing this, use the Lazy<T> class:

public class ViewModel
{
    private Lazy<ObservableCollection<TData>> Data;

    async public ViewModel()
    {
        Data = new Lazy<ObservableCollection<TData>>(GetDataTask);
    }

    public ObservableCollection<TData> GetDataTask()
    {
        Task<ObservableCollection<TData>> task;

        //Create a task which represents getting the data
        return task.GetAwaiter().GetResult();
    }
}

To use Data, use Data.Value.

How to read a file without newlines?

Try this:

u=open("url.txt","r")  
url=u.read().replace('\n','')  
print(url)  

How to get the last N rows of a pandas DataFrame?

This is because of using integer indices (ix selects those by label over -3 rather than position, and this is by design: see integer indexing in pandas "gotchas"*).

*In newer versions of pandas prefer loc or iloc to remove the ambiguity of ix as position or label:

df.iloc[-3:]

see the docs.

As Wes points out, in this specific case you should just use tail!

Get int from String, also containing letters, in Java

You can also use Scanner :

Scanner s = new Scanner(MyString);
s.nextInt();

Converting .NET DateTime to JSON

The previous answers all state that you can do the following:

var d = eval(net_datetime.slice(1, -1));

However, this doesn't work in either Chrome or FF because what's getting evaluated literally is:

// returns the current timestamp instead of the specified epoch timestamp
var d = Date([epoch timestamp]);

The correct way to do this is:

var d = eval("new " + net_datetime.slice(1, -1)); // which parses to

var d = new Date([epoch timestamp]); 

A Generic error occurred in GDI+ in Bitmap.Save method

    I used below logic while saving a .png format. This is to ensure the file is already existing or not.. if exist then saving it by adding 1 in the filename

Bitmap btImage = new Bitmap("D:\\Oldfoldername\\filename.png");
    string path="D:\\Newfoldername\\filename.png";
            int Count=0;
                if (System.IO.File.Exists(path))
                {
                    do
                    {
                        path = "D:\\Newfoldername\\filename"+"_"+ ++Count + ".png";                    
                    } while (System.IO.File.Exists(path));
                }

                btImage.Save(path, System.Drawing.Imaging.ImageFormat.Png);

Iterating through a Collection, avoiding ConcurrentModificationException when removing objects in a loop

Iterator.remove() is safe, you can use it like this:

List<String> list = new ArrayList<>();

// This is a clever way to create the iterator and call iterator.hasNext() like
// you would do in a while-loop. It would be the same as doing:
//     Iterator<String> iterator = list.iterator();
//     while (iterator.hasNext()) {
for (Iterator<String> iterator = list.iterator(); iterator.hasNext();) {
    String string = iterator.next();
    if (string.isEmpty()) {
        // Remove the current element from the iterator and the list.
        iterator.remove();
    }
}

Note that Iterator.remove() is the only safe way to modify a collection during iteration; the behavior is unspecified if the underlying collection is modified in any other way while the iteration is in progress.

Source: docs.oracle > The Collection Interface


And similarly, if you have a ListIterator and want to add items, you can use ListIterator#add, for the same reason you can use Iterator#remove — it's designed to allow it.


In your case you tried to remove from a list, but the same restriction applies if trying to put into a Map while iterating its content.

Maximum Length of Command Line String

In Windows 10, it's still 8191 characters...at least on my machine.

It just cuts off any text after 8191 characters. Well, actually, I got 8196 characters, and after 8196, then it just won't let me type any more.

Here's a script that will test how long of a statement you can use. Well, assuming you have gawk/awk installed.

echo rem this is a test of how long of a line that a .cmd script can generate >testbat.bat
gawk 'BEGIN {printf "echo -----";for (i=10;i^<=100000;i +=10) printf "%%06d----",i;print;print "pause";}' >>testbat.bat
testbat.bat

Sql query to insert datetime in SQL Server

No need to use convert. Simply list it as a quoted date in ISO 8601 format.
Like so:

select * from table1 where somedate between '2000/01/01' and '2099/12/31'

The separator needs to be a / and it needs to be surrounded by single ' quotes.

Echo a blank (empty) line to the console from a Windows batch file

There is often the tip to use 'echo.'

But that is slow, and it could fail with an error message, as cmd.exe will search first for a file named 'echo' (without extension) and only when the file doesn't exists it outputs an empty line.

You could use echo(. This is approximately 20 times faster, and it works always. The only drawback could be that it looks odd.

More about the different ECHO:/\ variants is at DOS tips: ECHO. FAILS to give text or blank line.

CSS submit button weird rendering on iPad/iPhone

The above answer for webkit appearance worked, but the button still looked kind pale/dull compared to the browser on other devices/desktop. I also had to set opacity to full (ranges from 0 to 1)

-webkit-appearance:none;
opacity: 1

After setting the opacity, the button looked the same on all the different devices/emulator/desktop.

jQuery AJAX form using mail() PHP script sends email, but POST data from HTML form is undefined

Leave your email.php code the same, but replace this JavaScript code:

 var name = $("#form_name").val();
        var email = $("#form_email").val();
        var text = $("#msg_text").val();
        var dataString = 'name='+ name + '&email=' + email + '&text=' + text;

        $.ajax({
            type: "POST",
            url: "email.php",
            data: dataString,
            success: function(){
            $('.success').fadeIn(1000);
            }
        });

with this:

    $.ajax({
        type: "POST",
        url: "email.php",
        data: $(form).serialize(),
        success: function(){
        $('.success').fadeIn(1000);
        }
    });

So that your form input names match up.

Ignoring NaNs with str.contains

df[df.col.str.contains("foo").fillna(False)]

WPF loading spinner

use an enum type to indicate your ViewModel's State

public enum ViewModeType
{
    Default, 
    Busy
    //etc.
}

then in your ViewModels Base class use a property

public ViewModeType ViewMode
{
    get { return this.viewMode; }
    set
    {
        if (this.viewMode != value)
        {
            this.viewMode = value;
                            //You should notify property changed here
        }
    }
}

and in view trigger the ViewMode and if it is busy show busyindicator:

<Trigger Property="ViewMode" Value="Busy">
    <!-- Show BusyIndicator -->
</Trigger>

2 "style" inline css img tags?

Do not use more than one style attribute. Just seperate styles in the style attribute with ; It is a block of inline CSS, so think of this as you would do CSS in a separate stylesheet.

So in this case its: style="height:100px;width:100px;"

You can use this for any CSS style, so if you wanted to change the colour of the text to white: style="height:100px;width:100px;color:#ffffff" and so on.

However, it is worth using inline CSS sparingly, as it can make code less manageable in future. Using an external stylesheet may be a better option for this. It depends really on your requirements. Inline CSS does make for quicker coding.

Express.js Response Timeout

In case you would like to use timeout middleware and exclude a specific route:

var timeout = require('connect-timeout');
app.use(timeout('5s')); //set 5s timeout for all requests

app.use('/my_route', function(req, res, next) {
    req.clearTimeout(); // clear request timeout
    req.setTimeout(20000); //set a 20s timeout for this request
    next();
}).get('/my_route', function(req, res) {
    //do something that takes a long time
});

Keep the order of the JSON keys during JSON conversion to CSV

JSONObject.java takes whatever map you pass. It may be LinkedHashMap or TreeMap and it will take hashmap only when the map is null .

Here is the constructor of JSONObject.java class that will do the checking of map.

 public JSONObject(Map paramMap)
  {
    this.map = (paramMap == null ? new HashMap() : paramMap);
  }

So before building a json object construct LinkedHashMap and then pass it to the constructor like this ,

LinkedHashMap<String, String> jsonOrderedMap = new LinkedHashMap<String, String>();

jsonOrderedMap.put("1","red");
jsonOrderedMap.put("2","blue");
jsonOrderedMap.put("3","green");

JSONObject orderedJson = new JSONObject(jsonOrderedMap);

JSONArray jsonArray = new JSONArray(Arrays.asList(orderedJson));

System.out.println("Ordered JSON Fianl CSV :: "+CDL.toString(jsonArray));

So there is no need to change the JSONObject.java class . Hope it helps somebody .

twitter bootstrap typeahead ajax example

All of the responses refer to BootStrap 2 typeahead, which is no longer present in BootStrap 3.

For anyone else directed here looking for an AJAX example using the new post-Bootstrap Twitter typeahead.js, here's a working example. The syntax is a little different:

$('#mytextquery').typeahead({
  hint: true,
  highlight: true,
  minLength: 1
},
{
  limit: 12,
  async: true,
  source: function (query, processSync, processAsync) {
    processSync(['This suggestion appears immediately', 'This one too']);
    return $.ajax({
      url: "/ajax/myfilter.php", 
      type: 'GET',
      data: {query: query},
      dataType: 'json',
      success: function (json) {
        // in this example, json is simply an array of strings
        return processAsync(json);
      }
    });
  }
});

This example uses both synchronous (the call to processSync) and asynchronous suggestion, so you'd see some options appear immediately, then others are added. You can just use one or the other.

There are lots of bindable events and some very powerful options, including working with objects rather than strings, in which case you'd use your own custom display function to render your items as text.

How to crop a CvMat in OpenCV?

To create a copy of the crop we want, we can do the following,

// Read img
cv::Mat img = cv::imread("imgFileName");
cv::Mat croppedImg;

// This line picks out the rectangle from the image
// and copies to a new Mat
img(cv::Rect(xMin,yMin,xMax-xMin,yMax-yMin)).copyTo(croppedImg);

// Display diff
cv::imshow( "Original Image",  img );
cv::imshow( "Cropped Image",  croppedImg);
cv::waitKey();

Python JSON dump / append to .txt with each variable on new line

To avoid confusion, paraphrasing both question and answer. I am assuming that user who posted this question wanted to save dictionary type object in JSON file format but when the user used json.dump, this method dumped all its content in one line. Instead, he wanted to record each dictionary entry on a new line. To achieve this use:

with g as outfile:
  json.dump(hostDict, outfile,indent=2)

Using indent = 2 helped me to dump each dictionary entry on a new line. Thank you @agf. Rewriting this answer to avoid confusion.

Validate Dynamically Added Input fields

You should have 'name' attribute for your inputs. You need to add the rules dynamically, one option is to add them when the form submits.

And here is my solution that I've tested and it works:

<script type="text/javascript">
   $(document).ready(function() {
        var numberIncr = 1; // used to increment the name for the inputs

        function addInput() {
            $('#inputs').append($('<input class="comment" name="name'+numberIncr+'" />'));
            numberIncr++;
        }

        $('form.commentForm').on('submit', function(event) {

            // adding rules for inputs with class 'comment'
            $('input.comment').each(function() {
                $(this).rules("add", 
                    {
                        required: true
                    })
            });            

            // prevent default submit action         
            event.preventDefault();

            // test if form is valid 
            if($('form.commentForm').validate().form()) {
                console.log("validates");
            } else {
                console.log("does not validate");
            }
        })

        // set handler for addInput button click
        $("#addInput").on('click', addInput);

        // initialize the validator
        $('form.commentForm').validate();

   });


</script>

And the html form part:

<form class="commentForm" method="get" action="">
    <div>

        <p id="inputs">    
            <input class="comment" name="name0" />
        </p>

    <input class="submit" type="submit" value="Submit" />
    <input type="button" value="add" id="addInput" />

    </div>
</form>

Good luck! Please approve answer if it suits you!

How to I say Is Not Null in VBA

you can do like follows. Remember, IsNull is a function which returns TRUE if the parameter passed to it is null, and false otherwise.

Not IsNull(Fields!W_O_Count.Value)

Java: parse int value from a char

Try Character.getNumericValue(char).

String element = "el5";
int x = Character.getNumericValue(element.charAt(2));
System.out.println("x=" + x);

produces:

x=5

The nice thing about getNumericValue(char) is that it also works with strings like "el?" and "el?" where ? and ? are the digits 5 in Eastern Arabic and Hindi/Sanskrit respectively.

How do you get the current text contents of a QComboBox?

PyQt4 can be forced to use a new API in which QString is automatically converted to and from a Python object:

import sip
sip.setapi('QString', 2)

With this API, QtCore.QString class is no longer available and self.ui.comboBox.currentText() will return a Python string or unicode object.

See Selecting Incompatible APIs from the doc.

Reinitialize Slick js after successful ajax call

After calling an request, set timeout to initialize slick slider.

var options = {
    arrows: false,
    slidesToShow: 1,
    variableWidth: true,
    centerPadding: '10px'
}

$.ajax({
    type: "GET",
    url: review_url+"?page="+page,
    success: function(result){
        setTimeout(function () {
            $(".reviews-page-carousel").slick(options)
        }, 500);
    }
})

Do not initialize slick slider at start. Just initialize after an AJAX with timeout. That should work for you.

Create a unique number with javascript time

function getUniqueNumber() {

    function shuffle(str) {
        var a = str.split("");
        var n = a.length;
        for(var i = n - 1; i > 0; i--) {
            var j = Math.floor(Math.random() * (i + 1));
            var tmp = a[i];
            a[i] = a[j];
            a[j] = tmp;
        }
        return a.join("");
    }
    var str = new Date().getTime() + (Math.random()*999 +1000).toFixed() //string
    return Number.parseInt(shuffle(str));   
}

How to fix error ::Format of the initialization string does not conform to specification starting at index 0::

I was facing the same problem and found out that my connection string had an extra double-quote character in the middle of the connection string.

Android button font size

Another programmatically approach;

final Button btn = (Button) findViewById(R.id.btnSize);

        final float[] size = {12};

        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                size[0] +=2;
                btn.setTextSize(size[0] +2);
            }
        });

Every time you click your button, Button text will be change (+2px size). You can add another button and change size -2px too. If you want to save size for another openings, you may use Shared Preference interface.

How do I calculate the date in JavaScript three months prior to today?

var d = new Date();
d.setMonth(d.getMonth() - 3);

This works for January. Run this snippet:

_x000D_
_x000D_
var d = new Date("January 14, 2012");_x000D_
console.log(d.toLocaleDateString());_x000D_
d.setMonth(d.getMonth() - 3);_x000D_
console.log(d.toLocaleDateString());
_x000D_
_x000D_
_x000D_


There are some caveats...

A month is a curious thing. How do you define 1 month? 30 days? Most people will say that one month ago means the same day of the month on the previous month citation needed. But more than half the time, that is 31 days ago, not 30. And if today is the 31st of the month (and it isn't August or Decemeber), that day of the month doesn't exist in the previous month.

Interestingly, Google agrees with JavaScript if you ask it what day is one month before another day:

Google search result for 'one month before March 31st' shows 'March 3rd'

It also says that one month is 30.4167 days long: Google search result for 'one month in days' shows '30.4167'

So, is one month before March 31st the same day as one month before March 28th, 3 days earlier? This all depends on what you mean by "one month before". Go have a conversation with your product owner.

If you want to do like momentjs does, and correct these last day of the month errors by moving to the last day of the month, you can do something like this:

_x000D_
_x000D_
const d = new Date("March 31, 2019");_x000D_
console.log(d.toLocaleDateString());_x000D_
const month = d.getMonth();_x000D_
d.setMonth(d.getMonth() - 1);_x000D_
while (d.getMonth() === month) {_x000D_
    d.setDate(d.getDate() - 1);_x000D_
}_x000D_
console.log(d.toLocaleDateString());
_x000D_
_x000D_
_x000D_

If your requirements are more complicated than that, use some math and write some code. You are a developer! You don't have to install a library! You don't have to copy and paste from stackoverflow! You can develop the code yourself to do precisely what you need!

How to set a JVM TimeZone Properly

You can pass the JVM this param

-Duser.timezone

For example

-Duser.timezone=Europe/Sofia

and this should do the trick. Setting the environment variable TZ also does the trick on Linux.

Login to Microsoft SQL Server Error: 18456

Another worked solution for me. serever->security->logins->new logins->General->create your user name as login name,Click sql server authentication add passwords

uncheck the password verification three checkboxes . This will work.

Remeber to change the server properties ->Security from Server authentication to SQL Server and Windows Authentication mode

Docker remove <none> TAG images

docker system prune will do the trick, it removes

- all stopped containers
- all networks not used by at least one container
- all dangling images
- all dangling build cache

But use it, with the caution!

How do you use math.random to generate random ints?

As an alternative, if there's not a specific reason to use Math.random(), use Random.nextInt():

import java.util.Random;

Random rnd = new Random();
int abc = rnd.nextInt(100); // +1 if you want 1-100, otherwise will be 0-99.

Multiple files upload (Array) with CodeIgniter 2.0

SO what I change is I load upload library each time

                $config = array();
                $config['upload_path'] = $filePath;
                $config['allowed_types'] = 'gif|jpg|png';
                $config['max_size']      = '0';
                $config['overwrite']     = FALSE;

                $files = $_FILES;
                $count = count($_FILES['nameUpload']['name']);


                for($i=0; $i<$count; $i++)
                {
                    $this->load->library('upload', $config);

                    $_FILES['nameUpload']['name']= $files['nameUpload']['name'][$i];
                    $_FILES['nameUpload']['type']= $files['nameUpload']['type'][$i];
                    $_FILES['nameUpload']['tmp_name']= $files['nameUpload']['tmp_name'][$i];
                    $_FILES['nameUpload']['error']= $files['nameUpload']['error'][$i];
                    $_FILES['nameUpload']['size']= $files['nameUpload']['size'][$i];

                    $this->upload->do_upload('nameUpload');
                }

And it work for me.

How to check ASP.NET Version loaded on a system?

You can use

<%
Response.Write("Version: " + System.Environment.Version.ToString());
%>

That will get the currently running version. You can check the registry for all installed versions at:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP

Use and meaning of "in" in an if statement?

Here raw_input is string, so if you wanted to check, if var>3 then you should convert next to double, ie float(next) and do as you would do if float(next)>3:, but in most cases

Reset ID autoincrement ? phpmyadmin

I agree with rpd, this is the answer and can be done on a regular basis to clean up your id column that is getting bigger with only a few hundred rows of data, but maybe an id of 34444543!, as the data is deleted out regularly but id is incremented automatically.

ALTER TABLE users DROP id

The above sql can be run via sql query or as php. This will delete the id column.

Then re add it again, via the code below:

ALTER TABLE  `users` ADD `id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY FIRST

Place this in a piece of code that may get run maybe in an admin panel, so when anyone enters that page it will run this script that auto cleans your database, and tidys it.

C# Select elements in list as List of string

List<string> empnames = emplist.Select(e => e.Ename).ToList();

This is an example of Projection in Linq. Followed by a ToList to resolve the IEnumerable<string> into a List<string>.

Alternatively in Linq syntax (head compiled):

var empnamesEnum = from emp in emplist 
                   select emp.Ename;
List<string> empnames = empnamesEnum.ToList();

Projection is basically representing the current type of the enumerable as a new type. You can project to anonymous types, another known type by calling constructors etc, or an enumerable of one of the properties (as in your case).

For example, you can project an enumerable of Employee to an enumerable of Tuple<int, string> like so:

var tuples = emplist.Select(e => new Tuple<int, string>(e.EID, e.Ename));

Update TensorFlow

For anaconda installation, first pick a channel which has the latest version of tensorflow binary. Usually, the latest versions are available at the channel conda-forge. Then simply do:

conda update -f -c conda-forge tensorflow

This will upgrade your existing tensorflow installation to the very latest version available. As of this writing, the latest version is 1.4.0-py36_0

How to parse data in JSON format?

For URL or file, use json.load(). For string with .json content, use json.loads().

#! /usr/bin/python

import json
# from pprint import pprint

json_file = 'my_cube.json'
cube = '1'

with open(json_file) as json_data:
    data = json.load(json_data)

# pprint(data)

print "Dimension: ", data['cubes'][cube]['dim']
print "Measures:  ", data['cubes'][cube]['meas']

Using Apache POI how to read a specific excel column

You could just loop the rows and read the same cell from each row (doesn't this comprise a column?).

TypeError: expected str, bytes or os.PathLike object, not _io.BufferedReader

I think it has to do with your second element in storbinary. You are trying to open file, but it is already a pointer to the file you opened in line file = open(local_path,'rb'). So, try to use ftp.storbinary("STOR " + i, file).

Fatal error: Call to undefined function socket_create()

I got this error when my .env file was not set up properly. Make sure you have a .env file with valid database login credentials.

C++ multiline string literal

Option 1. Using boost library, you can declare the string as below

const boost::string_view helpText = "This is very long help text.\n"
      "Also more text is here\n"
      "And here\n"

// Pass help text here
setHelpText(helpText);

Option 2. If boost is not available in your project, you can use std::string_view() in modern C++.

Importing a Maven project into Eclipse from Git

Direct answer: Go to Files>>Import>>Git>>Project From Git (you should have GIT installed on Eclips)

how to emulate "insert ignore" and "on duplicate key update" (sql merge) with postgresql?

On bulk, you can always delete the row before the insert. A deletion of a row that doesn't exist doesn't cause an error, so its safely skipped.

Best way to get the max value in a Spark dataframe column

First add the import line:

from pyspark.sql.functions import min, max

To find the min value of age in the dataframe:

df.agg(min("age")).show()

+--------+
|min(age)|
+--------+
|      29|
+--------+

To find the max value of age in the dataframe:

df.agg(max("age")).show()

+--------+
|max(age)|
+--------+
|      77|
+--------+

How to construct a WebSocket URI relative to the page URI?

easy:

location.href.replace(/^http/, 'ws') + '/to/ws'
// or if you hate regexp:
location.href.replace('http://', 'ws://').replace('https://', 'wss://') + '/to/ws'

How can I make visible an invisible control with jquery? (hide and show not work)

Here's some code I use to deal with this.

First we show the element, which will typically set the display type to "block" via .show() function, and then set the CSS rule to "visible":

jQuery( '.element' ).show().css( 'visibility', 'visible' );

Or, assuming that the class that is hiding the element is called hidden, such as in Twitter Bootstrap, toggleClass() can be useful:

jQuery( '.element' ).toggleClass( 'hidden' );

Lastly, if you want to chain functions, perhaps with fancy with a fading effect, you can do it like so:

jQuery( '.element' ).css( 'visibility', 'visible' ).fadeIn( 5000 );

Android Button click go to another xml page

Write below code in your MainActivity.java file instead of your code.

public class MainActivity extends Activity implements OnClickListener {

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

        Button mBtn1 = (Button) findViewById(R.id.mBtn1);
        mBtn1.setOnClickListener(this);
    }

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

    @Override
    public void onClick(View v) {
        Log.i("clicks","You Clicked B1");
        Intent i=new Intent(MainActivity.this, MainActivity2.class);
        startActivity(i);
    }
}

And Declare MainActivity2 into your Androidmanifest.xml file using below code.

<activity
    android:name=".MainActivity2"
    android:label="@string/title_activity_main">
</activity>

npm start error with create-react-app

I solve this issue by running following command

echo fs.inotify.max_user_watches=524288 | sudo tee -a /etc/sysctl.conf && sudo sysctl -p

hope it helps

How to find out when an Oracle table was updated the last time

If the auditing is enabled on the server, just simply use

SELECT *
FROM ALL_TAB_MODIFICATIONS
WHERE TABLE_NAME IN ()

Comparing Dates in Oracle SQL

You can use trunc and to_date as follows:

select TO_CHAR (g.FECHA, 'DD-MM-YYYY HH24:MI:SS') fecha_salida, g.NUMERO_GUIA, g.BOD_ORIGEN, g.TIPO_GUIA, dg.DOC_NUMERO, dg.* 
from ils_det_guia dg, ils_guia g
where dg.NUMERO_GUIA = g.NUMERO_GUIA and dg.TIPO_GUIA = g.TIPO_GUIA and dg.BOD_ORIGEN = g.BOD_ORIGEN
and dg.LAB_CODIGO = 56 
and trunc(g.FECHA) > to_date('01/02/15','DD/MM/YY')
order by g.FECHA;

Detecting Enter keypress on VB.NET

I see this has been answered, but it seems like you could avoid all of this 'remapping' of the enter key by simply hooking your validation into the AcceptButton on a form. ie. you have 3 textboxes (txtA,txtB,txtC) and an 'OK' button set to be AcceptButton (and TabOrder set properly). So, if in txtA and you hit enter, if the data is invalid, your focus will stay in txtA, but if it is valid, assuming the other txts need input, validation will just put you into the next txt that needs valid input thus simulating TAB behaviour... once all txts have valid input, pressing enter will fire a succsessful validation and close form (or whatever...) Make sense?

Do you use source control for your database items?

Wow, so many answers. For solid database versioning you need to version control the code that changes your database. Some CMS offer configuration management tools, such as the one in Drupal 8. Here is an overview with practical steps to arrange your workflow and ensure the database configuration is versioned, even in team environments:

Start service in Android

Probably you don't have the service in your manifest, or it does not have an <intent-filter> that matches your action. Examining LogCat (via adb logcat, DDMS, or the DDMS perspective in Eclipse) should turn up some warnings that may help.

More likely, you should start the service via:

startService(new Intent(this, UpdaterServiceManager.class));

In laymans terms, what does 'static' mean in Java?

Above points are correct and I want to add some more important points about Static keyword.

Internally what happening when you are using static keyword is it will store in permanent memory(that is in heap memory),we know that there are two types of memory they are stack memory(temporary memory) and heap memory(permanent memory),so if you are not using static key word then will store in temporary memory that is in stack memory(or you can call it as volatile memory).

so you will get a doubt that what is the use of this right???

example: static int a=10;(1 program)

just now I told if you use static keyword for variables or for method it will store in permanent memory right.

so I declared same variable with keyword static in other program with different value.

example: static int a=20;(2 program)

the variable 'a' is stored in heap memory by program 1.the same static variable 'a' is found in program 2 at that time it won`t create once again 'a' variable in heap memory instead of that it just replace value of a from 10 to 20.

In general it will create once again variable 'a' in stack memory(temporary memory) if you won`t declare 'a' as static variable.

overall i can say that,if we use static keyword
  1.we can save memory
  2.we can avoid duplicates
  3.No need of creating object in-order to access static variable with the help of class name you can access it.

Multiple lines of text in UILabel

In this function pass string that you want to assign in label and pass font size in place of self.activityFont and pass label width in place of 235, now you get label height according to your string. it will work fine.

-(float)calculateLabelStringHeight:(NSString *)answer
{
    CGRect textRect = [answer boundingRectWithSize: CGSizeMake(235, 10000000) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:self.activityFont} context:nil];
    return textRect.size.height;

}

Using CSS to align a button bottom of the screen using relative positions

<button style="position: absolute; left: 20%; right: 20%; bottom: 5%;"> Button </button>

SQL query to get most recent row for each instance of a given key

Try this:

Select u.[username]
      ,u.[ip]
      ,q.[time_stamp]
From [users] As u
Inner Join (
    Select [username]
          ,max(time_stamp) as [time_stamp]
    From [users]
    Group By [username]) As [q]
On u.username = q.username
And u.time_stamp = q.time_stamp

How to do logging in React Native?

If you are on osx and using an emulator, you can view your console.logs directly in safari web inspector.

Safari => Development => Simulator - [your simulator version here] => JSContext

Application Installation Failed in Android Studio

Try disabling the Instant run in Settings.

How to detect pressing Enter on keyboard using jQuery?

You can do this using the jquery 'keydown' event handle

   $( "#start" ).on( "keydown", function(event) {
      if(event.which == 13) 
         alert("Entered!");
    });

Fragment Inside Fragment

AFAIK, fragments cannot hold other fragments.


UPDATE

With current versions of the Android Support package -- or native fragments on API Level 17 and higher -- you can nest fragments, by means of getChildFragmentManager(). Note that this means that you need to use the Android Support package version of fragments on API Levels 11-16, because even though there is a native version of fragments on those devices, that version does not have getChildFragmentManager().

Eclipse java debugging: source not found

Remove the existing Debug Configuration and create a new one. That should resolve the problem.

Where to find "Microsoft.VisualStudio.TestTools.UnitTesting" missing dll?

There is also a nice nuget package. It will pull the dll to your packages folder. You will need to add the reference to the dll manually.

NOTE: This package is not an official Microsoft package.

How to fix corrupted git repository?

TL;DR

Git doesn't really store history the way you think it does. It calculates history at run-time based on an ancestor chain. If your ancestry is missing blobs, trees, or commits then you may not be able to fully recover your history.

Restore Missing Objects from Backups

The first thing you can try is to restore the missing items from backup. For example, see if you have a backup of the commit stored as .git/objects/98/4c11abfc9c2839b386f29c574d9e03383fa589. If so you can restore it.

You may also want to look into git-verify-pack and git-unpack-objects in the event that the commit has already been packed up and you want to return it to a loose object for the purposes of repository surgery.

Surgical Resection

If you can't replace the missing items from a backup, you may be able to excise the missing history. For example, you might examine your history or reflog to find an ancestor of commit 984c11abfc9c2839b386f29c574d9e03383fa589. If you find one intact, then:

  1. Copy your Git working directory to a temporary directory somewhere.
  2. Do a hard reset to the uncorrupted commit.
  3. Copy your current files back into the Git work tree, but make sure you don't copy the .git folder back!
  4. Commit the current work tree, and do your best to treat it as a squashed commit of all the missing history.

If it works, you will of course lose the intervening history. At this point, if you have a working history log, then it's a good idea to prune your history and reflogs of all unreachable commits and objects.

Full Restores and Re-Initialization

If your repository is still broken, then hopefully you have an uncorrupted backup or clone you can restore from. If not, but your current working directory contains valid files, then you can always re-initialize Git. For example:

rm -rf .git
git init
git add .
git commit -m 'Re-initialize repository without old history.'

It's drastic, but it may be your only option if your repository history is truly unrecoverable. YMMV.

Oracle query to fetch column names

You may try this : ( It works on 11g and it returns all column name from a table , here test_tbl is the table name and user_tab_columns are user permitted table's columns )

select  COLUMN_NAME  from user_tab_columns
where table_name='test_tbl'; 

Will #if RELEASE work like #if DEBUG does in C#?

I've never seen that before...but I have seen:

#if (DEBUG == FALSE)

and

#if (!DEBUG)

That work for ya?

Hide element by class in pure Javascript

var appBanners = document.getElementsByClassName('appBanner');

for (var i = 0; i < appBanners.length; i ++) {
    appBanners[i].style.display = 'none';
}

JSFiddle.

Read tab-separated file line into array

If you really want to split every word (bash meaning) into a different array index completely changing the array in every while loop iteration, @ruakh's answer is the correct approach. But you can use the read property to split every read word into different variables column1, column2, column3 like in this code snippet

while IFS=$'\t' read -r column1 column2 column3 ; do
  printf "%b\n" "column1<${column1}>"
  printf "%b\n" "column2<${column2}>"
  printf "%b\n" "column3<${column3}>"
done < "myfile"

to reach a similar result avoiding array index access and improving your code readability by using meaningful variable names (of course using columnN is not a good idea to do so).

How to fix request failed on channel 0

As you already found the -T flag that create a PTY, I will just respond to the second part:

shell request failed on channel 0

You should pass a command:

ssh [email protected] -p 22 help

After reading back the manual here: https://www.jenkins.io/doc/book/managing/cli/, I find it not really clear that it would not work without a command. But as stated by @U.V., the ssh interface is not a console interface, rather a connection utility. So you need to pass a command...

If someone from the "jenkins" team pass accross this post, it would be great that if we pass no command, the help would show up :-)

Linq Syntax - Selecting multiple columns

You can use anonymous types for example:

  var empData = from res in _db.EMPLOYEEs
                where res.EMAIL == givenInfo || res.USER_NAME == givenInfo
                select new { res.EMAIL, res.USER_NAME };

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

The biggest issue being missed by most solutions here is that an element's width is often changed by CSS based on where it is scoped in html.

If I was to determine offsetWidth of an element by appending a clone of it to body when it has styles that only apply in its current scope I would get the wrong width.

for example:

//css

.module-container .my-elem{ border: 60px solid black; }

now when I try to determine my-elem's width in context of body it will be out by 120px. You could clone the module container instead, but your JS shouldn't have to know these details.

I haven't tested it but essentially Soul_Master's solution appears to be the only one that could work properly. But unfortunately looking at the implementation it will likely be costly to use and bad for performance (as most of the solutions presented here are as well.)

If at all possible then use visibility: hidden instead. This will still render the element, allowing you to calculate width without all the fuss.

successful/fail message pop up box after submit?

You are echoing outside the body tag of your HTML. Put your echos there, and you should be fine.

Also, remove the onclick="alert()" from your submit. This is the cause for your first undefined message.

<?php
  $posted = false;
  if( $_POST ) {
    $posted = true;

    // Database stuff here...
    // $result = mysql_query( ... )
    $result = $_POST['name'] == "danny"; // Dummy result
  }
?>

<html>
  <head></head>
  <body>

  <?php
    if( $posted ) {
      if( $result ) 
        echo "<script type='text/javascript'>alert('submitted successfully!')</script>";
      else
        echo "<script type='text/javascript'>alert('failed!')</script>";
    }
  ?>
    <form action="" method="post">
      Name:<input type="text" id="name" name="name"/>
      <input type="submit" value="submit" name="submit"/>
    </form>
  </body>
</html>

The apk must be signed with the same certificates as the previous version

If you have previous apk file with you(backup) then use jarSigner to extract certificate from that that apk, then use that key or use keytool to clone that certificate, may be that will help... Helpful links are jarsigner docs and keytool docs.

Where can I download an offline installer of Cygwin?

If all you want is the UNIX command line tools I'd suggest not installing Cygwin. Cygwin wants to turn your Windows PC into a UNIX Workstation which is why it likes to install all its packages.

Have a look at GnuWin32 instead. It's Windows ports of the command line tools and nothing else. Here is the installer for the GnuWin32 diff.exe. There are offline installers for all the common tools.

(You asked for offline installers but in case you ever want one later there is a tool which will download and install everything for you.)

Method 2: make an offline install zip file for cygwin.

Don't mess with saving packages because the installed directory for cygwin can be canned in a zip file and expanded whenever you need it on any computer.

  1. Download Cygwin installer

  2. pick packages you want installed from gui.

  3. hit install and wait a really long time for everything to download.

  4. zip up the C:\Cygwin folder. Now you have your offline zip file for installing cygwin on any machine.

  5. Unzip this file on whatever computer you like. set cmd.exe paths appropriately to point to cygwin bin directory under windows control panel.

What does the 'Z' mean in Unix timestamp '120314170138Z'?

The Z stands for 'Zulu' - your times are in UTC. From Wikipedia:

The UTC time zone is sometimes denoted by the letter Z—a reference to the equivalent nautical time zone (GMT), which has been denoted by a Z since about 1950. The letter also refers to the "zone description" of zero hours, which has been used since 1920 (see time zone history). Since the NATO phonetic alphabet and amateur radio word for Z is "Zulu", UTC is sometimes known as Zulu time. This is especially true in aviation, where Zulu is the universal standard.

MAX(DATE) - SQL ORACLE

Try with:

select TO_CHAR(dates,'dd/MM/yyy hh24:mi') from (  SELECT min  (TO_DATE(a.PAYM_DATE)) as dates from user_payment a )

What does "zend_mm_heap corrupted" mean

I had this same issue and when I had an incorrect IP for session.save_path for memcached sessions. Changing it to the correct IP fixed the problem.

How to check empty DataTable

As from MSDN for GetChanges

A filtered copy of the DataTable that can have actions performed on it, and later be merged back in the DataTable using Merge. If no rows of the desired DataRowState are found, the method returns Nothing (null).

dataTable1 is null so just check before you iterate over it.

Convert String to Float in Swift

Using the accepted solution, I was finding that my "1.1" (when using the .floatValue conversion) would get converted to 1.10000002384186, which was not what I wanted. However, if I used the .doubleValue instead, I would get the 1.1 that I wanted.

So for example, instead of using the accepted solution, I used this instead:

var WageConversion = (Wage.text as NSString).doubleValue

In my case I did not need double-precision, but using the .floatValue was not giving me the proper result.

Just wanted to add this to the discussion in case someone else had been running into the same issue.

Freeing up a TCP/IP port?

If you really want to kill a process immediately, you send it a KILL signal instead of a TERM signal (the latter a request to stop, the first will take effect immediately without any cleanup). It is easy to do:

kill -KILL <pid>

Be aware however that depending on the program you are stopping, its state may get badly corrupted when doing so. You normally only want to send a KILL signal when normal termination does not work. I'm wondering what the underlying problem is that you try to solve and whether killing is the right solution.

java.lang.IllegalStateException: Only fullscreen opaque activities can request orientation

I had the same problem, and my solution was to eliminate the line

android:screenOrientation="portrait"

and then add this in the activity:

if (android.os.Build.VERSION.SDK_INT < Build.VERSION_CODES.O) {
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
}

Starting ssh-agent on Windows 10 fails: "unable to start ssh-agent service, error :1058"

Yeah, as others have suggested, this error seems to mean that ssh-agent is installed but its service (on windows) hasn't been started.

You can check this by running in Windows PowerShell:

> Get-Service ssh-agent

And then check the output of status is not running.

Status   Name               DisplayName
------   ----               -----------
Stopped  ssh-agent          OpenSSH Authentication Agent

Then check that the service has been disabled by running

> Get-Service ssh-agent | Select StartType

StartType
---------
Disabled

I suggest setting the service to start manually. This means that as soon as you run ssh-agent, it'll start the service. You can do this through the Services GUI or you can run the command in admin mode:

 > Get-Service -Name ssh-agent | Set-Service -StartupType Manual

Alternatively, you can set it through the GUI if you prefer.

services.msc showing the properties of the OpenSSH Agent

How can I check if a URL exists via PHP?

When figuring out if an url exists from php there are a few things to pay attention to:

  • Is the url itself valid (a string, not empty, good syntax), this is quick to check server side.
  • Waiting for a response might take time and block code execution.
  • Not all headers returned by get_headers() are well formed.
  • Use curl (if you can).
  • Prevent fetching the entire body/content, but only request the headers.
  • Consider redirecting urls:
  • Do you want the first code returned?
  • Or follow all redirects and return the last code?
  • You might end up with a 200, but it could redirect using meta tags or javascript. Figuring out what happens after is tough.

Keep in mind that whatever method you use, it takes time to wait for a response.
All code might (and probably will) halt untill you either know the result or the requests have timed out.

For example: the code below could take a LONG time to display the page if the urls are invalid or unreachable:

<?php
$urls = getUrls(); // some function getting say 10 or more external links

foreach($urls as $k=>$url){
  // this could potentially take 0-30 seconds each
  // (more or less depending on connection, target site, timeout settings...)
  if( ! isValidUrl($url) ){
    unset($urls[$k]);
  }
}

echo "yay all done! now show my site";
foreach($urls as $url){
  echo "<a href=\"{$url}\">{$url}</a><br/>";
}

The functions below could be helpfull, you probably want to modify them to suit your needs:

    function isValidUrl($url){
        // first do some quick sanity checks:
        if(!$url || !is_string($url)){
            return false;
        }
        // quick check url is roughly a valid http request: ( http://blah/... ) 
        if( ! preg_match('/^http(s)?:\/\/[a-z0-9-]+(\.[a-z0-9-]+)*(:[0-9]+)?(\/.*)?$/i', $url) ){
            return false;
        }
        // the next bit could be slow:
        if(getHttpResponseCode_using_curl($url) != 200){
//      if(getHttpResponseCode_using_getheaders($url) != 200){  // use this one if you cant use curl
            return false;
        }
        // all good!
        return true;
    }
    
    function getHttpResponseCode_using_curl($url, $followredirects = true){
        // returns int responsecode, or false (if url does not exist or connection timeout occurs)
        // NOTE: could potentially take up to 0-30 seconds , blocking further code execution (more or less depending on connection, target site, and local timeout settings))
        // if $followredirects == false: return the FIRST known httpcode (ignore redirects)
        // if $followredirects == true : return the LAST  known httpcode (when redirected)
        if(! $url || ! is_string($url)){
            return false;
        }
        $ch = @curl_init($url);
        if($ch === false){
            return false;
        }
        @curl_setopt($ch, CURLOPT_HEADER         ,true);    // we want headers
        @curl_setopt($ch, CURLOPT_NOBODY         ,true);    // dont need body
        @curl_setopt($ch, CURLOPT_RETURNTRANSFER ,true);    // catch output (do NOT print!)
        if($followredirects){
            @curl_setopt($ch, CURLOPT_FOLLOWLOCATION ,true);
            @curl_setopt($ch, CURLOPT_MAXREDIRS      ,10);  // fairly random number, but could prevent unwanted endless redirects with followlocation=true
        }else{
            @curl_setopt($ch, CURLOPT_FOLLOWLOCATION ,false);
        }
//      @curl_setopt($ch, CURLOPT_CONNECTTIMEOUT ,5);   // fairly random number (seconds)... but could prevent waiting forever to get a result
//      @curl_setopt($ch, CURLOPT_TIMEOUT        ,6);   // fairly random number (seconds)... but could prevent waiting forever to get a result
//      @curl_setopt($ch, CURLOPT_USERAGENT      ,"Mozilla/5.0 (Windows NT 6.0) AppleWebKit/537.1 (KHTML, like Gecko) Chrome/21.0.1180.89 Safari/537.1");   // pretend we're a regular browser
        @curl_exec($ch);
        if(@curl_errno($ch)){   // should be 0
            @curl_close($ch);
            return false;
        }
        $code = @curl_getinfo($ch, CURLINFO_HTTP_CODE); // note: php.net documentation shows this returns a string, but really it returns an int
        @curl_close($ch);
        return $code;
    }
    
    function getHttpResponseCode_using_getheaders($url, $followredirects = true){
        // returns string responsecode, or false if no responsecode found in headers (or url does not exist)
        // NOTE: could potentially take up to 0-30 seconds , blocking further code execution (more or less depending on connection, target site, and local timeout settings))
        // if $followredirects == false: return the FIRST known httpcode (ignore redirects)
        // if $followredirects == true : return the LAST  known httpcode (when redirected)
        if(! $url || ! is_string($url)){
            return false;
        }
        $headers = @get_headers($url);
        if($headers && is_array($headers)){
            if($followredirects){
                // we want the last errorcode, reverse array so we start at the end:
                $headers = array_reverse($headers);
            }
            foreach($headers as $hline){
                // search for things like "HTTP/1.1 200 OK" , "HTTP/1.0 200 OK" , "HTTP/1.1 301 PERMANENTLY MOVED" , "HTTP/1.1 400 Not Found" , etc.
                // note that the exact syntax/version/output differs, so there is some string magic involved here
                if(preg_match('/^HTTP\/\S+\s+([1-9][0-9][0-9])\s+.*/', $hline, $matches) ){// "HTTP/*** ### ***"
                    $code = $matches[1];
                    return $code;
                }
            }
            // no HTTP/xxx found in headers:
            return false;
        }
        // no headers :
        return false;
    }

Incompatible implicit declaration of built-in function ‘malloc’

You need to #include <stdlib.h>. Otherwise it's defined as int malloc() which is incompatible with the built-in type void *malloc(size_t).

Clear all fields in a form upon going back with browser back button

If you need to compatible with older browsers as well "pageshow" option might not work. Following code worked for me.

$(window).load(function() {
    $('form').get(0).reset(); //clear form data on page load
});

How do I break out of a loop in Scala?

Here is a tail recursive version. Compared to the for-comprehensions it is a bit cryptic, admittedly, but I'd say its functional :)

def run(start:Int) = {
  @tailrec
  def tr(i:Int, largest:Int):Int = tr1(i, i, largest) match {
    case x if i > 1 => tr(i-1, x)
    case _ => largest
  }

  @tailrec
  def tr1(i:Int,j:Int, largest:Int):Int = i*j match {
    case x if x < largest || j < 2 => largest
    case x if x.toString.equals(x.toString.reverse) => tr1(i, j-1, x)
    case _ => tr1(i, j-1, largest)
  }

  tr(start, 0)
}

As you can see, the tr function is the counterpart of the outer for-comprehensions, and tr1 of the inner one. You're welcome if you know a way to optimize my version.

sudo in php exec()

It sounds like you need to set up passwordless sudo. Try:

%admin ALL=(ALL) NOPASSWD: osascript myscript.scpt

Also comment out the following line (in /etc/sudoers via visudo), if it is there:

Defaults    requiretty

How can I send JSON response in symfony2 controller

Symfony 2.1

$response = new Response(json_encode(array('name' => $name)));
$response->headers->set('Content-Type', 'application/json');

return $response;

Symfony 2.2 and higher

You have special JsonResponse class, which serialises array to JSON:

return new JsonResponse(array('name' => $name));

But if your problem is How to serialize entity then you should have a look at JMSSerializerBundle

Assuming that you have it installed, you'll have simply to do

$serializedEntity = $this->container->get('serializer')->serialize($entity, 'json');

return new Response($serializedEntity);

You should also check for similar problems on StackOverflow:

What does .shape[] do in "for i in range(Y.shape[0])"?

The shape attribute for numpy arrays returns the dimensions of the array. If Y has n rows and m columns, then Y.shape is (n,m). So Y.shape[0] is n.

In [46]: Y = np.arange(12).reshape(3,4)

In [47]: Y
Out[47]: 
array([[ 0,  1,  2,  3],
       [ 4,  5,  6,  7],
       [ 8,  9, 10, 11]])

In [48]: Y.shape
Out[48]: (3, 4)

In [49]: Y.shape[0]
Out[49]: 3

what is the difference between ajax and jquery and which one is better?

Ajax is a technology / paradigm, whereas jquery is a library (which provides - besides other nice functionality - a convenient wrapper around ajax) - thus you can't compare them.

How do I protect Python code?

The best you can do with Python is to obscure things.

  • Strip out all docstrings
  • Distribute only the .pyc compiled files.
  • freeze it
  • Obscure your constants inside a class/module so that help(config) doesn't show everything

You may be able to add some additional obscurity by encrypting part of it and decrypting it on the fly and passing it to eval(). But no matter what you do someone can break it.

None of this will stop a determined attacker from disassembling the bytecode or digging through your api with help, dir, etc.

How to select an element with 2 classes

You can chain class selectors without a space between them:

.a.b {
     color: #666;
}

Note that, if it matters to you, IE6 treats .a.b as .b, so in that browser both div.a.b and div.b will have gray text. See this answer for a comparison between proper browsers and IE6.

Check if a number is odd or even in python

It shouldn't matter if the word has an even or odd amount fo letters:

def is_palindrome(word):
    if word == word[::-1]:
        return True
    else:
        return False

How to access URL segment(s) in blade in Laravel 5?

BASED ON LARAVEL 5.7 & ABOVE

To get all segments of current URL:

$current_uri = request()->segments();

To get segment posts from http://example.com/users/posts/latest/

NOTE: Segments are an array that starts at index 0. The first element of array starts after the TLD part of the url. So in the above url, segment(0) will be users and segment(1) will be posts.

//get segment 0
$segment_users = request()->segment(0); //returns 'users'
//get segment 1
$segment_posts = request()->segment(1); //returns 'posts'

You may have noted that the segment method only works with the current URL ( url()->current() ). So I designed a method to work with previous URL too by cloning the segment() method:

public function index()
{
    $prev_uri_segments = $this->prev_segments(url()->previous());
}

 /**
 * Get all of the segments for the previous uri.
 *
 * @return array
 */
public function prev_segments($uri)
{
    $segments = explode('/', str_replace(''.url('').'', '', $uri));

    return array_values(array_filter($segments, function ($value) {
        return $value !== '';
    }));
}

Empty set literal?

Just to extend the accepted answer:

From version 2.7 and 3.1 python has got set literal {} in form of usage {1,2,3}, but {} itself still used for empty dict.

Python 2.7 (first line is invalid in Python <2.7)

>>> {1,2,3}.__class__
<type 'set'>
>>> {}.__class__
<type 'dict'>

Python 3.x

>>> {1,2,3}.__class__
<class 'set'>
>>> {}.__class__
<class 'dict'>

More here: https://docs.python.org/3/whatsnew/2.7.html#other-language-changes

How to copy data to clipboard in C#

Clip.exe is an executable in Windows to set the clipboard. Note that this does not work for other operating systems other than Windows, which still sucks.

        /// <summary>
        /// Sets clipboard to value.
        /// </summary>
        /// <param name="value">String to set the clipboard to.</param>
        public static void SetClipboard(string value)
        {
            if (value == null)
                throw new ArgumentNullException("Attempt to set clipboard with null");

            Process clipboardExecutable = new Process(); 
            clipboardExecutable.StartInfo = new ProcessStartInfo // Creates the process
            {
                RedirectStandardInput = true,
                FileName = @"clip", 
            };
            clipboardExecutable.Start();

            clipboardExecutable.StandardInput.Write(value); // CLIP uses STDIN as input.
            // When we are done writing all the string, close it so clip doesn't wait and get stuck
            clipboardExecutable.StandardInput.Close(); 

            return;
        }

For loop in Objective-C

You mean fast enumeration? You question is very unclear.

A normal for loop would look a bit like this:

unsigned int i, cnt = [someArray count];
for(i = 0; i < cnt; i++)
{ 
   // do loop stuff
   id someObject = [someArray objectAtIndex:i];
}

And a loop with fast enumeration, which is optimized by the compiler, would look like this:

for(id someObject in someArray)
{
   // do stuff with object
}

Keep in mind that you cannot change the array you are using in fast enumeration, thus no deleting nor adding when using fast enumeration

Detect if the device is iPhone X

You shall perform different detections of iPhone X depending on the actual need.

for dealing with the top notch (statusbar, navbar), etc.

class var hasTopNotch: Bool {
    if #available(iOS 11.0, tvOS 11.0, *) {
        // with notch: 44.0 on iPhone X, XS, XS Max, XR.
        // without notch: 24.0 on iPad Pro 12.9" 3rd generation, 20.0 on iPhone 8 on iOS 12+.
        return UIApplication.shared.delegate?.window??.safeAreaInsets.top ?? 0 > 24
    }
    return false
}

for dealing with the bottom home indicator (tabbar), etc.

class var hasBottomSafeAreaInsets: Bool {
    if #available(iOS 11.0, tvOS 11.0, *) {
        // with home indicator: 34.0 on iPhone X, XS, XS Max, XR.
        // with home indicator: 20.0 on iPad Pro 12.9" 3rd generation.
        return UIApplication.shared.delegate?.window??.safeAreaInsets.bottom ?? 0 > 0
    }
    return false
}

for backgrounds size, fullscreen features, etc.

class var isIphoneXOrBigger: Bool {
    // 812.0 on iPhone X, XS.
    // 896.0 on iPhone XS Max, XR.
    return UIScreen.main.bounds.height >= 812
}

Note: eventually mix it with UIDevice.current.userInterfaceIdiom == .phone
Note: this method requires to have a LaunchScreen storyboard or proper LaunchImages

for backgrounds ratio, scrolling features, etc.

class var isIphoneXOrLonger: Bool {
    // 812.0 / 375.0 on iPhone X, XS.
    // 896.0 / 414.0 on iPhone XS Max, XR.
    return UIScreen.main.bounds.height / UIScreen.main.bounds.width >= 896.0 / 414.0
}

Note: this method requires to have a LaunchScreen storyboard or proper LaunchImages

for analytics, stats, tracking, etc.

Get the machine identifier and compare it to documented values:

class var isIphoneX: Bool {
    var size = 0
    sysctlbyname("hw.machine", nil, &size, nil, 0)
    var machine = [CChar](repeating: 0, count: size)
    sysctlbyname("hw.machine", &machine, &size, nil, 0)
    let model = String(cString: machine)
    return model == "iPhone10,3" || model == "iPhone10,6"
}

To include the simulator as a valid iPhone X in your analytics:

class var isIphoneX: Bool {
    let model: String
    if TARGET_OS_SIMULATOR != 0 {
        model = ProcessInfo.processInfo.environment["SIMULATOR_MODEL_IDENTIFIER"] ?? ""
    } else {
        var size = 0
        sysctlbyname("hw.machine", nil, &size, nil, 0)
        var machine = [CChar](repeating: 0, count: size)
        sysctlbyname("hw.machine", &machine, &size, nil, 0)
        model = String(cString: machine)
    }
    return model == "iPhone10,3" || model == "iPhone10,6"
}

To include iPhone XS, XS Max and XR, simply look for models starting with "iPhone11,":

return model == "iPhone10,3" || model == "iPhone10,6" || model.starts(with: "iPhone11,")

for faceID support

import LocalAuthentication
/// will fail if user denies canEvaluatePolicy(_:error:)
class var canUseFaceID: Bool {
    if #available(iOS 11.0, *) {
        return LAContext().biometryType == .typeFaceID
    }
    return false
}

How to change TextField's height and width?

You can try the margin property in the Container. Wrap the TextField inside a Container and adjust the margin property.

new Container(
  margin: const EdgeInsets.only(right: 10, left: 10),
  child: new TextField( 
    decoration: new InputDecoration(
      hintText: 'username',
      icon: new Icon(Icons.person)),
  )
),

how to change the dist-folder path in angular-cli after 'ng build'

Another option would be to set the webroot path to the angular cli dist folder. In your Program.cs when configuring the WebHostBuilder just say

.UseWebRoot(Directory.GetCurrentDirectory() + "\\Frontend\\dist")

or whatever the path to your dist dir is.

MySQL does not start when upgrading OSX to Yosemite or El Capitan

Long story short you need to create a launch file. So, from Terminal:

sudo vi /Library/LaunchDaemons/com.mysql.mysql.plist

(If you are not familiar with vi, then press i to start inserting text)

This should be the content of your file:

<?xml version="1.0" encoding="UTF-8"?> 
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
  <dict>
    <key>KeepAlive</key>
    <true />
    <key>Label</key>
    <string>com.mysql.mysqld</string>
    <key>ProgramArguments</key>
    <array>
      <string>/usr/local/mysql/bin/mysqld_safe</string>
      <string>--user=mysql</string>
    </array>
  </dict>
</plist>

press esc then : wq!enter

Then you need to give the file the right permissions and set it to load on startup.

sudo chown root:wheel /Library/LaunchDaemons/com.mysql.mysql.plist 
sudo chmod 644 /Library/LaunchDaemons/com.mysql.mysql.plist 
sudo launchctl load -w /Library/LaunchDaemons/com.mysql.mysql.plist

And that is it.

Squash the first two commits in Git?

This will squash second commit into the first one:

A-B-C-... -> AB-C-...

git filter-branch --commit-filter '
    if [ "$GIT_COMMIT" = <sha1ofA> ];
    then
        skip_commit "$@";
    else
        git commit-tree "$@";
    fi
' HEAD

Commit message for AB will be taken from B (although I'd prefer from A).

Has the same effect as Uwe Kleine-König's answer, but works for non-initial A as well.

Debugging Stored Procedure in SQL Server 2008

One requirement for remote debugging is that the windows account used to run SSMS be part of the sysadmin role. See this MSDN link: http://msdn.microsoft.com/en-us/library/cc646024%28v=sql.105%29.aspx

No Hibernate Session bound to thread, and configuration does not allow creation of non-transactional one here

I resolved this by adding @Transactional to the base/generic Hibernate DAO implementation class (the parent class which implements the saveOrUpdate() method inherited by the DAO I use in the main program), i.e. the @Transactional needs to be specified on the actual class which implements the method. My assumption was instead that if I declared @Transactional on the child class then it included all of the methods that were inherited by the child class. However it seems that the @Transactional annotation only applies to methods implemented within a class and not to methods inherited by a class.

How to concatenate items in a list to a single string?

def eggs(someParameter):
    del spam[3]
    someParameter.insert(3, ' and cats.')


spam = ['apples', 'bananas', 'tofu', 'cats']
eggs(spam)
spam =(','.join(spam))
print(spam)

Remove an array element and shift the remaining ones

If you are most concerned about code size and/or performance (also for WCET analysis, if you need one), I think this is probably going to be one of the more transparent solutions (for finding and removing elements):

unsigned int l=0, removed=0;

for( unsigned int i=0; i<count; i++ ) {
    if( array[i] != to_remove )
        array[l++] = array[i];
    else
        removed++;
}

count -= removed;

Select a Dictionary<T1, T2> with LINQ

A more explicit option is to project collection to an IEnumerable of KeyValuePair and then convert it to a Dictionary.

Dictionary<int, string> dictionary = objects
    .Select(x=> new KeyValuePair<int, string>(x.Id, x.Name))
    .ToDictionary(x=>x.Key, x=>x.Value);

Manually Triggering Form Validation using jQuery

For input field

<input id="PrimaryPhNumber" type="text" name="mobile"  required
                                       pattern="^[789]\d{9}$" minlenght="10" maxLength="10" placeholder="Eg: 9444400000"
                                       class="inputBoxCss"/>
$('#PrimaryPhNumber').keyup(function (e) {
        console.log(e)
        let field=$(this)
        if(Number(field.val()).toString()=="NaN"){
            field.val('');
            field.focus();
            field[0].setCustomValidity('Please enter a valid phone number');
            field[0].reportValidity()
            $(":focus").css("border", "2px solid red");
        }
    })

How can I call a method in Objective-C?

[self score]; instead of @selector(score)

How do I check that a number is float or integer?

For integers I use this

function integer_or_null(value) {
    if ((undefined === value) || (null === value)) {
        return null;
    }
    if(value % 1 != 0) {
        return null;
    }
    return value;
}

TypeError: Can't convert 'int' object to str implicitly

def attributeSelection():
balance = 25
print("Your SP balance is currently 25.")
strength = input("How much SP do you want to put into strength?")
balanceAfterStrength = balance - int(strength)
if balanceAfterStrength == 0:
    print("Your SP balance is now 0.")
    attributeConfirmation()
elif strength < 0:
    print("That is an invalid input. Restarting attribute selection. Keep an eye on your balance this time!")
    attributeSelection()
elif strength > balance:
    print("That is an invalid input. Restarting attribute selection. Keep an eye on your balance this time!")
    attributeSelection()
elif balanceAfterStrength > 0 and balanceAfterStrength < 26:
    print("Ok. You're balance is now at " + str(balanceAfterStrength) + " skill points.")
else:
    print("That is an invalid input. Restarting attribute selection.")
    attributeSelection()

How to convert image to byte array

To be convert the image to byte array.The code is give below.

public byte[] ImageToByteArray(System.Drawing.Image images)
{
   using (var _memorystream = new MemoryStream())
   {
      images.Save(_memorystream ,images.RawFormat);
      return  _memorystream .ToArray();
   }
}

To be convert the Byte array to Image.The code is given below.The code is handle A Generic error occurred in GDI+ in Image Save.

public void SaveImage(string base64String, string filepath)
{
    // image convert to base64string is base64String 
    //File path is which path to save the image.
    var bytess = Convert.FromBase64String(base64String);
    using (var imageFile = new FileStream(filepath, FileMode.Create))
    {
        imageFile.Write(bytess, 0, bytess.Length);
        imageFile.Flush();
    }
}

How to stop default link click behavior with jQuery

$('.update-cart').click(function(e) {
    updateCartWidget();
    e.stopPropagation();
    e.preventDefault();
});

$('.update-cart').click(function() {
    updateCartWidget();
    return false;
});

The following methods achieve the exact same thing.

How to round up integer division and have int result in Java?

To round up an integer division you can use

import static java.lang.Math.abs;

public static long roundUp(long num, long divisor) {
    int sign = (num > 0 ? 1 : -1) * (divisor > 0 ? 1 : -1);
    return sign * (abs(num) + abs(divisor) - 1) / abs(divisor);
}

or if both numbers are positive

public static long roundUp(long num, long divisor) {
    return (num + divisor - 1) / divisor;
}

Timing a command's execution in PowerShell

Just a word on drawing (incorrect) conclusions from any of the performance measurement commands referred to in the answers. There are a number of pitfalls that should taken in consideration aside from looking to the bare invocation time of a (custom) function or command.

Sjoemelsoftware

'Sjoemelsoftware' voted Dutch word of the year 2015
Sjoemelen means cheating, and the word sjoemelsoftware came into being due to the Volkswagen emissions scandal. The official definition is "software used to influence test results".

Personally, I think that "Sjoemelsoftware" is not always deliberately created to cheat test results but might originate from accommodating practical situation that are similar to test cases as shown below.

As an example, using the listed performance measurement commands, Language Integrated Query (LINQ)(1), is often qualified as the fasted way to get something done and it often is, but certainly not always! Anybody who measures a speed increase of a factor 40 or more in comparison with native PowerShell commands, is probably incorrectly measuring or drawing an incorrect conclusion.

The point is that some .Net classes (like LINQ) using a lazy evaluation (also referred to as deferred execution(2)). Meaning that when assign an expression to a variable, it almost immediately appears to be done but in fact it didn't process anything yet!

Let presume that you dot-source your . .\Dosomething.ps1 command which has either a PowerShell or a more sophisticated Linq expression (for the ease of explanation, I have directly embedded the expressions directly into the Measure-Command):

$Data = @(1..100000).ForEach{[PSCustomObject]@{Index=$_;Property=(Get-Random)}}

(Measure-Command {
    $PowerShell = $Data.Where{$_.Index -eq 12345}
}).totalmilliseconds
864.5237

(Measure-Command {
    $Linq = [Linq.Enumerable]::Where($Data, [Func[object,bool]] { param($Item); Return $Item.Index -eq 12345})
}).totalmilliseconds
24.5949

The result appears obvious, the later Linq command is a about 40 times faster than the first PowerShell command. Unfortunately, it is not that simple...

Let's display the results:

PS C:\> $PowerShell

Index  Property
-----  --------
12345 104123841

PS C:\> $Linq

Index  Property
-----  --------
12345 104123841

As expected, the results are the same but if you have paid close attention, you will have noticed that it took a lot longer to display the $Linq results then the $PowerShell results.
Let's specifically measure that by just retrieving a property of the resulted object:

PS C:\> (Measure-Command {$PowerShell.Property}).totalmilliseconds
14.8798
PS C:\> (Measure-Command {$Linq.Property}).totalmilliseconds
1360.9435

It took about a factor 90 longer to retrieve a property of the $Linq object then the $PowerShell object and that was just a single object!

Also notice an other pitfall that if you do it again, certain steps might appear a lot faster then before, this is because some of the expressions have been cached.

Bottom line, if you want to compare the performance between two functions, you will need to implement them in your used case, start with a fresh PowerShell session and base your conclusion on the actual performance of the complete solution.

(1) For more background and examples on PowerShell and LINQ, I recommend tihis site: High Performance PowerShell with LINQ
(2) I think there is a minor difference between the two concepts as with lazy evaluation the result is calculated when needed as apposed to deferred execution were the result is calculated when the system is idle

MySQL error 1241: Operand should contain 1 column(s)

Just remove the ( and the ) on your SELECT statement:

insert into table2 (Name, Subject, student_id, result)
select Name, Subject, student_id, result
from table1;

JavaScript Chart.js - Custom data formatting to display on tooltip

You need to make use of Label Callback. A common example to round data values, the following example rounds the data to two decimal places.

var chart = new Chart(ctx, {
    type: 'line',
    data: data,
    options: {
        tooltips: {
            callbacks: {
                label: function(tooltipItem, data) {
                    var label = data.datasets[tooltipItem.datasetIndex].label || '';

                    if (label) {
                        label += ': ';
                    }
                    label += Math.round(tooltipItem.yLabel * 100) / 100;
                    return label;
                }
            }
        }
    }
});

Now let me write the scenario where I used the label callback functionality.

Let's start with logging the arguments of Label Callback function, you will see structure similar to this here datasets, array comprises of different lines you want to plot in the chart. In my case it's 4, that's why length of datasets array is 4.

enter image description here

In my case, I had to perform some calculations on each dataset and have to identify the correct line, every-time I hover upon a line in a chart.

To differentiate different lines and manipulate the data of hovered tooltip based on the data of other lines I had to write this logic.

  callbacks: {
    label: function (tooltipItem, data) {
      console.log('data', data);
      console.log('tooltipItem', tooltipItem);
      let updatedToolTip: number;
      if (tooltipItem.datasetIndex == 0) {
        updatedToolTip = tooltipItem.yLabel;
      }
      if (tooltipItem.datasetIndex == 1) {
        updatedToolTip = tooltipItem.yLabel - data.datasets[0].data[tooltipItem.index];
      }
      if (tooltipItem.datasetIndex == 2) {
        updatedToolTip = tooltipItem.yLabel - data.datasets[1].data[tooltipItem.index];
      }
      if (tooltipItem.datasetIndex == 3) {
        updatedToolTip = tooltipItem.yLabel - data.datasets[2].data[tooltipItem.index]
      }
      return updatedToolTip;
    }
  } 

Above mentioned scenario will come handy, when you have to plot different lines in line-chart and manipulate tooltip of the hovered point of a line, based on the data of other point belonging to different line in the chart at the same index.

Error message Strict standards: Non-static method should not be called statically in php

If scope resolution :: had to be used outside the class then the respective function or variable should be declared as static

class Foo { 
        //Static variable 
        public static $static_var = 'static variable'; 
        //Static function 
        static function staticValue() { return 'static function'; } 

        //function 
        function Value() { return 'Object'; } 
} 



 echo Foo::$static_var . "<br/>"; echo Foo::staticValue(). "<br/>"; $foo = new Foo(); echo $foo->Value();

server error:405 - HTTP verb used to access this page is not allowed

In the Facebook app control panel make sure you have a forward slash on the end of any specified URL if you are only specifying a folder name

i.e.

Page Tab URL: http://mypagetabserver.com/custom_tab/

How do you do natural logs (e.g. "ln()") with numpy in Python?

from numpy.lib.scimath import logn
from math import e

#using: x - var
logn(e, x)

Referenced Project gets "lost" at Compile Time

Make sure that both projects have same target framework version here: right click on project -> properties -> application (tab) -> target framework

Also, make sure that the project "logger" (which you want to include in the main project) has the output type "Class Library" in: right click on project -> properties -> application (tab) -> output type

Finally, Rebuild the solution.

Merging Cells in Excel using C#

This solves the issue in the appropriate way

// Merge a row
            ws.Cell("B2").Value = "Merged Row(1) of Range (B2:D3)";
            ws.Range("B2:D3").Row(1).Merge();

Ruby combining an array into one string

While a bit more cryptic than join, you can also multiply the array by a string.

@arr * " "

New warnings in iOS 9: "all bitcode will be dropped"

In my case for avoiding that problem:

  1. Be sure that you are dealing with Xcode 7, NOT lower versions. In lower version this flag does not exist.

  2. Setup: Project>Build Settings>All>Build Options>Enable Bitcode = NO

enter image description here

How to prevent Browser cache for php site

Prevent browser cache is not a good idea depending on the case. Looking for a solution I found solutions like this:

<link rel="stylesheet" type="text/css" href="meu.css?v=<?=filemtime($file);?>">

the problem here is that if the file is overwritten during an update on the server, which is my scenario, the cache is ignored because timestamp is modified even the content of the file is the same.

I use this solution to force browser to download assets only if its content is modified:

<link rel="stylesheet" type="text/css" href="meu.css?v=<?=hash_file('md5', $file);?>">

How to get the function name from within that function?

This might work for you:

function foo() { bar(); }

function bar() { console.log(bar.caller.name); }

running foo() will output "foo" or undefined if you call from an anonymous function.

It works with constructors too, in which case it would output the name of the calling constructor (eg "Foo").

More info here: https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Function/Caller

They claim it's non-standard, but also that it's supported by all major browsers: Firefox, Safari, Chrome, Opera and IE.

Python, compute list difference

You can do a

list(set(A)-set(B))

and

list(set(B)-set(A))

What is the correct way to declare a boolean variable in Java?

In your example, You don't need to. As a standard programming practice, all variables being referred to inside some code block, say for example try{} catch(){}, and being referred to outside the block as well, you need to declare the variables outside the try block first e.g.

This is helpful when your equals method call throws some exception e.g. NullPointerException;

     boolean isMatch = false;

     try{
         isMatch = email1.equals (email2);
      }catch(NullPointerException npe){
         .....
      }
      System.out.print("Match=="+isMatch);
      if(isMatch){
        ......
      }

Find the index of a dict within a list, by matching the dict's value

It won't be efficient, as you need to walk the list checking every item in it (O(n)). If you want efficiency, you can use dict of dicts. On the question, here's one possible way to find it (though, if you want to stick to this data structure, it's actually more efficient to use a generator as Brent Newey has written in the comments; see also tokland's answer):

>>> L = [{'id':'1234','name':'Jason'},
...         {'id':'2345','name':'Tom'},
...         {'id':'3456','name':'Art'}]
>>> [i for i,_ in enumerate(L) if _['name'] == 'Tom'][0]
1

How to reload page the page with pagination in Angular 2?

This should technically be achievable using window.location.reload():

HTML:

<button (click)="refresh()">Refresh</button>

TS:

refresh(): void {
    window.location.reload();
}

Update:

Here is a basic StackBlitz example showing the refresh in action. Notice the URL on "/hello" path is retained when window.location.reload() is executed.

How can I convert ArrayList<Object> to ArrayList<String>?

You can use wildcard to do this as following

ArrayList<String> strList = (ArrayList<String>)(ArrayList<?>)(list);

How do you print in a Go test using the "testing" package?

For testing sometimes I do

fmt.Fprintln(os.Stdout, "hello")

Also, you can print to:

fmt.Fprintln(os.Stderr, "hello)

C# equivalent of C++ map<string,double>

Dictionary is the most common, but you can use other types of collections, e.g. System.Collections.Generic.SynchronizedKeyedCollection, System.Collections.Hashtable, or any KeyValuePair collection

How to parse JSON in Scala using standard Scala classes?

val jsonString =
  """
    |{
    | "languages": [{
    |     "name": "English",
    |     "is_active": true,
    |     "completeness": 2.5
    | }, {
    |     "name": "Latin",
    |     "is_active": false,
    |     "completeness": 0.9
    | }]
    |}
  """.stripMargin

val result = JSON.parseFull(jsonString).map {
  case json: Map[String, List[Map[String, Any]]] =>
    json("languages").map(l => (l("name"), l("is_active"), l("completeness")))
}.get

println(result)

assert( result == List(("English", true, 2.5), ("Latin", false, 0.9)) )

Calling a function in jQuery with click()

$("#closeLink").click(closeIt);

Let's say you want to call your function passing some args to it i.e., closeIt(1, false). Then, you should build an anonymous function and call closeIt from it.

$("#closeLink").click(function() {
    closeIt(1, false);
});

What's a good, free serial port monitor for reverse-engineering?

I'd get a logic analyzer and wire it up to the serial port. I think there are probably only two lines you need (Tx/Rx), so there should be plenty of cheap logic analyzers available. You don't have a clock line handy though, so that could get tricky.

Convert UTC datetime string to local datetime

import datetime

def utc_str_to_local_str(utc_str: str, utc_format: str, local_format: str):
    """
    :param utc_str: UTC time string
    :param utc_format: format of UTC time string
    :param local_format: format of local time string
    :return: local time string
    """
    temp1 = datetime.datetime.strptime(utc_str, utc_format)
    temp2 = temp1.replace(tzinfo=datetime.timezone.utc)
    local_time = temp2.astimezone()
    return local_time.strftime(local_format)

utc = '2018-10-17T00:00:00.111Z'
utc_fmt = '%Y-%m-%dT%H:%M:%S.%fZ'
local_fmt = '%Y-%m-%dT%H:%M:%S+08:00'
local_string = utc_str_to_local_str(utc, utc_fmt, local_fmt)
print(local_string)   # 2018-10-17T08:00:00+08:00

for example, my timezone is '+08:00'. input utc = 2018-10-17T00:00:00.111Z, then I will get output = 2018-10-17T08:00:00+08:00

How to scroll to the bottom of a RecyclerView? scrollToPosition doesn't work

this code will give you latest post first, i think this answer is helpful.

    mInstaList=(RecyclerView)findViewById(R.id.insta_list);
    mInstaList.setHasFixedSize(true);

    LinearLayoutManager layoutManager = new LinearLayoutManager(this);
    layoutManager.setOrientation(LinearLayoutManager.VERTICAL);

    mInstaList.setLayoutManager(layoutManager);
    layoutManager.setStackFromEnd(true);
    layoutManager.setReverseLayout(true);

Can Windows Containers be hosted on linux?

Containers use the OS kernel. Windows Container utilize processes in order to run. So theoretically speaking Windows Containers cannot run on Linux.

However there are workarounds utilizing VMstyle solutions.

I Have found this solution which uses Vagrant and Packer on Mac, so it should work for Linux as well: https://github.com/StefanScherer/windows-docker-machine

This Vagrant environment creates a Docker Machine to work on your MacBook with Windows containers. You can easily switch between Docker for Mac Linux containers and the Windows containers.

Running bash commands enter image description here

building the headless Vagrant box

$ git clone https://github.com/StefanScherer/packer-windows
$ cd packer-windows

$ packer build --only=vmware-iso windows_2019_docker.json
$ vagrant box add windows_2019_docker windows_2019_docker_vmware.box

Create the Docker Machine

$ git clone https://github.com/StefanScherer/windows-docker-machine
$ cd windows-docker-machine
$ vagrant up --provider vmware_fusion 2019

Switch to Windows containers

$ eval $(docker-machine env 2019)

PageSpeed Insights 99/100 because of Google Analytics - How can I cache GA?

In the Google docs, they've identified a pagespeed filter that will load the script asynchronously:

ModPagespeedEnableFilters make_google_analytics_async

You can find the documentation here: https://developers.google.com/speed/pagespeed/module/filter-make-google-analytics-async

One thing to highlight is that the filter is considered high risk. From the docs:

The make_google_analytics_async filter is experimental and has not had extensive real-world testing. One case where a rewrite would cause errors is if the filter misses calls to Google Analytics methods that return values. If such methods are found, the rewrite is skipped. However, the disqualifying methods will be missed if they come before the load, are in attributes such as "onclick", or if they are in external resources. Those cases are expected to be rare.

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

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

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

Combine Regexp?

Will the conditions be ORed or ANDed together?

Starts with: abc
Ends with: xyz
Contains: 123
Doesn't contain: 456

The OR version is fairly simple; as you said, it's mostly a matter of inserting pipes between individual conditions. The regex simply stops looking for a match as soon as one of the alternatives matches.

/^abc|xyz$|123|^(?:(?!456).)*$/

That fourth alternative may look bizarre, but that's how you express "doesn't contain" in a regex. By the way, the order of the alternatives doesn't matter; this is effectively the same regex:

/xyz$|^(?:(?!456).)*$|123|^abc/

The AND version is more complicated. After each individual regex matches, the match position has to be reset to zero so the next regex has access to the whole input. That means all of the conditions have to be expressed as lookaheads (technically, one of them doesn't have to be a lookahead, I think it expresses the intent more clearly this way). A final .*$ consummates the match.

/^(?=^abc)(?=.*xyz$)(?=.*123)(?=^(?:(?!456).)*$).*$/

And then there's the possibility of combined AND and OR conditions--that's where the real fun starts. :D

How to fix missing dependency warning when using useEffect React Hook?

./src/components/BusinessesList.js
Line 51:  React Hook useEffect has a missing dependency: 'fetchBusinesses'.
Either include it or remove the dependency array  react-hooks/exhaustive-deps

It's not JS/React error but eslint (eslint-plugin-react-hooks) warning.

It's telling you that hook depends on function fetchBusinesses, so you should pass it as dependency.

useEffect(() => {
  fetchBusinesses();
}, [fetchBusinesses]);

It could result in invoking function every render if function is declared in component like:

const Component = () => {
  /*...*/

  //new function declaration every render
  const fetchBusinesses = () => {
    fetch('/api/businesses/')
      .then(...)
  }

  useEffect(() => {
    fetchBusinesses();
  }, [fetchBusinesses]);

  /*...*/
}

because every time function is redeclared with new reference

Correct way of doing this stuff is:

const Component = () => {
  /*...*/

  // keep function reference
  const fetchBusinesses = useCallback(() => {
    fetch('/api/businesses/')
      .then(...)
  }, [/* additional dependencies */]) 

  useEffect(() => {
    fetchBusinesses();
  }, [fetchBusinesses]);

  /*...*/
}

or just defining function in useEffect

More: https://github.com/facebook/react/issues/14920

Django 1.7 - "No migrations to apply" when run migrate after makemigrations

  1. In MySQL Database delete row 'profiles' from the table 'django_migrations'.
  2. Delete all migration files in migrations folder.
  3. Try again python manage.py makemigrations and python manage.py migrate command.

Is it possible to display inline images from html in an Android TextView?

I faced the same problem and I've found a pretty clean solution: After Html.fromHtml() you can run an AsyncTask that iterates over all the tags, fetches the images and then displays them.

Here you can find some code that you can use (but it needs some customization): https://gist.github.com/1190397

Purge or recreate a Ruby on Rails database

I know two ways to do this:

This will reset your database and reload your current schema with all:

rake db:reset db:migrate

This will destroy your db and then create it and then migrate your current schema:

rake db:drop db:create db:migrate

All data will be lost in both scenarios.

Find all special characters in a column in SQL Server 2008

Negatives are your friend here:

SELECT Col1
FROM TABLE
WHERE Col1 like '%[^a-Z0-9]%'

Which says that you want any rows where Col1 consists of any number of characters, then one character not in the set a-Z0-9, and then any number of characters.

If you have a case sensitive collation, it's important that you use a range that includes both upper and lower case A, a, Z and z, which is what I've given (originally I had it the wrong way around. a comes before A. Z comes after z)


Or, to put it another way, you could have written your original WHERE as:

Col1 LIKE '[!@#$%]'

But, as you observed, you'd need to know all of the characters to include in the [].

PowerShell and the -contains operator

The -Contains operator doesn't do substring comparisons and the match must be on a complete string and is used to search collections.

From the documentation you linked to:

-Contains Description: Containment operator. Tells whether a collection of reference values includes a single test value.

In the example you provided you're working with a collection containing just one string item.

If you read the documentation you linked to you'll see an example that demonstrates this behaviour:

Examples:

PS C:\> "abc", "def" -Contains "def"
True

PS C:\> "Windows", "PowerShell" -Contains "Shell"
False  #Not an exact match

I think what you want is the -Match operator:

"12-18" -Match "-"

Which returns True.

Important: As pointed out in the comments and in the linked documentation, it should be noted that the -Match operator uses regular expressions to perform text matching.

How do I use setsockopt(SO_REUSEADDR)?

I think you should use SO_LINGER options (with timeout 0). In this case, you connection will close immediately after closing your program; and next restart will be able to bind again.

example:

linger lin;
lin.l_onoff = 0;
lin.l_linger = 0;
setsockopt(fd, SOL_SOCKET, SO_LINGER, (const char *)&lin, sizeof(int));

see definition: http://man7.org/linux/man-pages/man7/socket.7.html

SO_LINGER
          Sets or gets the SO_LINGER option.  The argument is a linger
          structure.

              struct linger {
                  int l_onoff;    /* linger active */
                  int l_linger;   /* how many seconds to linger for */
              };

          When enabled, a close(2) or shutdown(2) will not return until
          all queued messages for the socket have been successfully sent
          or the linger timeout has been reached.  Otherwise, the call
          returns immediately and the closing is done in the background.
          When the socket is closed as part of exit(2), it always
          lingers in the background.

More about SO_LINGER: TCP option SO_LINGER (zero) - when it's required

Regular Expression for any number greater than 0?

I Tried this one and it worked for me for all decimal/integer numbers greater than zero

Allows white space: ^\s*(?=.*[1-9])\d*(?:\.\d{1,2})?\s*$

No white space: ^(?=.*[1-9])\d*(?:\.\d{1,2})?$

Reference: Regex greater than zero with 2 decimal places

How to avoid java.util.ConcurrentModificationException when iterating through and removing elements from an ArrayList

Do the loop in the normal way, the java.util.ConcurrentModificationException is an error related to the elements that are accessed.

So try:

for(int i = 0; i < list.size(); i++){
    lista.get(i).action();
}

How to implement one-to-one, one-to-many and many-to-many relationships while designing tables?

Here are some real-world examples of the types of relationships:

One-to-one (1:1)

A relationship is one-to-one if and only if one record from table A is related to a maximum of one record in table B.

To establish a one-to-one relationship, the primary key of table B (with no orphan record) must be the secondary key of table A (with orphan records).

For example:

CREATE TABLE Gov(
    GID number(6) PRIMARY KEY, 
    Name varchar2(25), 
    Address varchar2(30), 
    TermBegin date,
    TermEnd date
); 

CREATE TABLE State(
    SID number(3) PRIMARY KEY,
    StateName varchar2(15),
    Population number(10),
    SGID Number(4) REFERENCES Gov(GID), 
    CONSTRAINT GOV_SDID UNIQUE (SGID)
);

INSERT INTO gov(GID, Name, Address, TermBegin) 
values(110, 'Bob', '123 Any St', '1-Jan-2009');

INSERT INTO STATE values(111, 'Virginia', 2000000, 110);

One-to-many (1:M)

A relationship is one-to-many if and only if one record from table A is related to one or more records in table B. However, one record in table B cannot be related to more than one record in table A.

To establish a one-to-many relationship, the primary key of table A (the "one" table) must be the secondary key of table B (the "many" table).

For example:

CREATE TABLE Vendor(
    VendorNumber number(4) PRIMARY KEY,
    Name varchar2(20),
    Address varchar2(20),
    City varchar2(15),
    Street varchar2(2),
    ZipCode varchar2(10),
    Contact varchar2(16),
    PhoneNumber varchar2(12),
    Status varchar2(8),
    StampDate date
);

CREATE TABLE Inventory(
    Item varchar2(6) PRIMARY KEY,
    Description varchar2(30),
    CurrentQuantity number(4) NOT NULL,
    VendorNumber number(2) REFERENCES Vendor(VendorNumber),
    ReorderQuantity number(3) NOT NULL
);

Many-to-many (M:M)

A relationship is many-to-many if and only if one record from table A is related to one or more records in table B and vice-versa.

To establish a many-to-many relationship, create a third table called "ClassStudentRelation" which will have the primary keys of both table A and table B.

CREATE TABLE Class(
    ClassID varchar2(10) PRIMARY KEY, 
    Title varchar2(30),
    Instructor varchar2(30), 
    Day varchar2(15), 
    Time varchar2(10)
);

CREATE TABLE Student(
    StudentID varchar2(15) PRIMARY KEY, 
    Name varchar2(35),
    Major varchar2(35), 
    ClassYear varchar2(10), 
    Status varchar2(10)
);  

CREATE TABLE ClassStudentRelation(
    StudentID varchar2(15) NOT NULL,
    ClassID varchar2(14) NOT NULL,
    FOREIGN KEY (StudentID) REFERENCES Student(StudentID), 
    FOREIGN KEY (ClassID) REFERENCES Class(ClassID),
    UNIQUE (StudentID, ClassID)
);

C - casting int to char and append char to char

Casting int to char involves losing data and the compiler will probably warn you.

Extracting a particular byte from an int sounds more reasonable and can be done like this:

number & 0x000000ff; /* first byte */
(number & 0x0000ff00) >> 8; /* second byte */
(number & 0x00ff0000) >> 16; /* third byte */
(number & 0xff000000) >> 24; /* fourth byte */

Using FFmpeg in .net?

A solution that is viable for both Linux and Windows is to just get used to using console ffmpeg in your code. I stack up threads, write a simple thread controller class, then you can easily make use of what ever functionality of ffmpeg you want to use.

As an example, this contains sections use ffmpeg to create a thumbnail from a time that I specify.

In the thread controller you have something like

List<ThrdFfmpeg> threads = new List<ThrdFfmpeg>();

Which is the list of threads that you are running, I make use of a timer to Pole these threads, you can also set up an event if Pole'ing is not suitable for your application. In this case thw class Thrdffmpeg contains,

public class ThrdFfmpeg
{
    public FfmpegStuff ffm { get; set; }
    public Thread thrd { get; set; }
}

FFmpegStuff contains the various ffmpeg functionality, thrd is obviously the thread.

A property in FfmpegStuff is the class FilesToProcess, which is used to pass information to the called process, and receive information once the thread has stopped.

public class FileToProcess
{
    public int videoID { get; set; }
    public string fname { get; set; }
    public int durationSeconds { get; set; }
    public List<string> imgFiles { get; set; }
}

VideoID (I use a database) tells the threaded process which video to use taken from the database. fname is used in other parts of my functions that use FilesToProcess, but not used here. durationSeconds - is filled in by the threads that just collect video duration. imgFiles is used to return any thumbnails that were created.

I do not want to get bogged down in my code when the purpose of this is to encourage the use of ffmpeg in easily controlled threads.

Now we have our pieces we can add to our threads list, so in our controller we do something like,

        AddThread()
        {
        ThrdFfmpeg thrd;
        FileToProcess ftp;

        foreach(FileToProcess ff in  `dbhelper.GetFileNames(txtCategory.Text))`
        {
            //make a thread for each
            ftp = new FileToProcess();
            ftp = ff;
            ftp.imgFiles = new List<string>();
            thrd = new ThrdFfmpeg();
            thrd.ffm = new FfmpegStuff();
            thrd.ffm.filetoprocess = ftp;
            thrd.thrd = new   `System.Threading.Thread(thrd.ffm.CollectVideoLength);`

         threads.Add(thrd);
        }
        if(timerNotStarted)
             StartThreadTimer();
        }

Now Pole'ing our threads becomes a simple task,

private void timerThreads_Tick(object sender, EventArgs e)
    {
        int runningCount = 0;
        int finishedThreads = 0;
        foreach(ThrdFfmpeg thrd in threads)
        {
            switch (thrd.thrd.ThreadState)
            {
                case System.Threading.ThreadState.Running:
                    ++runningCount;


 //Note that you can still view data progress here,
    //but remember that you must use your safety checks
    //here more than anywhere else in your code, make sure the data
    //is readable and of the right sort, before you read it.
                    break;
                case System.Threading.ThreadState.StopRequested:
                    break;
                case System.Threading.ThreadState.SuspendRequested:
                    break;
                case System.Threading.ThreadState.Background:
                    break;
                case System.Threading.ThreadState.Unstarted:


//Any threads that have been added but not yet started, start now
                    thrd.thrd.Start();
                    ++runningCount;
                    break;
                case System.Threading.ThreadState.Stopped:
                    ++finishedThreads;


//You can now safely read the results, in this case the
   //data contained in FilesToProcess
   //Such as
                    ThumbnailsReadyEvent( thrd.ffm );
                    break;
                case System.Threading.ThreadState.WaitSleepJoin:
                    break;
                case System.Threading.ThreadState.Suspended:
                    break;
                case System.Threading.ThreadState.AbortRequested:
                    break;
                case System.Threading.ThreadState.Aborted:
                    break;
                default:
                    break;
            }
        }


        if(flash)
        {//just a simple indicator so that I can see
         //that at least one thread is still running
            lbThreadStatus.BackColor = Color.White;
            flash = false;
        }
        else
        {
            lbThreadStatus.BackColor = this.BackColor;
            flash = true;
        }
        if(finishedThreads >= threads.Count())
        {

            StopThreadTimer();
            ShowSample();
            MakeJoinedThumb();
        }
    }

Putting your own events onto into the controller class works well, but in video work, when my own code is not actually doing any of the video file processing, poling then invoking an event in the controlling class works just as well.

Using this method I have slowly built up just about every video and stills function I think I will ever use, all contained in the one class, and that class as a text file is useable on the Lunux and Windows version, with just a small number of pre-process directives.

Pandas group-by and sum

A variation on the .agg() function; provides the ability to (1) persist type DataFrame, (2) apply averages, counts, summations, etc. and (3) enables groupby on multiple columns while maintaining legibility.

df.groupby(['att1', 'att2']).agg({'att1': "count", 'att3': "sum",'att4': 'mean'})

using your values...

df.groupby(['Name', 'Fruit']).agg({'Number': "sum"})

How to convert int to NSString?

If this string is for presentation to the end user, you should use NSNumberFormatter. This will add thousands separators, and will honor the localization settings for the user:

NSInteger n = 10000;
NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
formatter.numberStyle = NSNumberFormatterDecimalStyle;
NSString *string = [formatter stringFromNumber:@(n)];

In the US, for example, that would create a string 10,000, but in Germany, that would be 10.000.

How to convert String object to Boolean Object?

you can directly set boolean value equivalent to any string by System class and access it anywhere..

System.setProperty("n","false");
System.setProperty("y","true");

System.setProperty("yes","true");     
System.setProperty("no","false");

System.out.println(Boolean.getBoolean("n"));   //false
System.out.println(Boolean.getBoolean("y"));   //true   
 System.out.println(Boolean.getBoolean("no"));  //false
System.out.println(Boolean.getBoolean("yes"));  //true

How to reload current page?

private router: Router

this.router.navigateByUrl(url)

It will redirect to any pages without data lost (even current page). Data will remain as is.

Update query with PDO and MySQL

This has nothing to do with using PDO, it's just that you are confusing INSERT and UPDATE.

Here's the difference:

  • INSERT creates a new row. I'm guessing that you really want to create a new row.
  • UPDATE changes the values in an existing row, but if this is what you're doing you probably should use a WHERE clause to restrict the change to a specific row, because the default is that it applies to every row.

So this will probably do what you want:

$sql = "INSERT INTO `access_users`   
  (`contact_first_name`,`contact_surname`,`contact_email`,`telephone`) 
  VALUES (:firstname, :surname, :email, :telephone);
  ";

Note that I've also changed the order of columns; the order of your columns must match the order of values in your VALUES clause.

MySQL also supports an alternative syntax for INSERT:

$sql = "INSERT INTO `access_users`   
  SET `contact_first_name` = :firstname,
    `contact_surname` = :surname,
    `contact_email` = :email,
    `telephone` = :telephone
  ";

This alternative syntax looks a bit more like an UPDATE statement, but it creates a new row like INSERT. The advantage is that it's easier to match up the columns to the correct parameters.

How to read GET data from a URL using JavaScript?

Iv'e fixed/improved Tomalak's answer with:

  • Make an Array only if needed.
  • If there's another equation symbol in the value it gets inside the value
  • It now uses the location.search value instead of a url.
  • Empty search string results in an empty object.

Code:

function getSearchObject() {
    if (location.search === "") return {};

    var o = {},
        nvPairs = location.search.substr(1).replace(/\+/g, " ").split("&");

    nvPairs.forEach( function (pair) {
        var e = pair.indexOf('=');
        var n = decodeURIComponent(e < 0 ? pair : pair.substr(0,e)),
            v = (e < 0 || e + 1 == pair.length) 
                ? null : 
                decodeURIComponent(pair.substr(e + 1,pair.length - e));
        if (!(n in o))
            o[n] = v;
        else if (o[n] instanceof Array)
            o[n].push(v);
        else
            o[n] = [o[n] , v];
    });
    return o;
}

How to use Python to execute a cURL command?

My answer is WRT python 2.6.2.

import commands

status, output = commands.getstatusoutput("curl -H \"Content-Type:application/json\" -k -u (few other parameters required) -X GET https://example.org -s")

print output

I apologize for not providing the required parameters 'coz it's confidential.

Getting Http Status code number (200, 301, 404, etc.) from HttpWebRequest and HttpWebResponse

As per 'dtb' you need to use HttpStatusCode, but following 'zeldi' you need to be extra careful with code responses >= 400.

This has worked for me:

HttpWebResponse response = null;
HttpStatusCode statusCode;
try
{
    response = (HttpWebResponse)request.GetResponse();
}
catch (WebException we)
{
    response = (HttpWebResponse)we.Response;
}

statusCode = response.StatusCode;
Stream dataStream = response.GetResponseStream();
StreamReader reader = new StreamReader(dataStream);
sResponse = reader.ReadToEnd();
Console.WriteLine(sResponse);
Console.WriteLine("Response Code: " + (int)statusCode + " - " + statusCode.ToString());

Remove scrollbars from textarea

Hide scroll bar for Mozilla.

  overflow: -moz-hidden-unscrollable;

How to create a generic array?

Problem is that while runtime generic type is erased so new E[10] would be equivalent to new Object[10].

This would be dangerous because it would be possible to put in array other data than of E type. That is why you need to explicitly say that type you want by either

How to abort a Task like aborting a Thread (Thread.Abort method)?

  1. You shouldn't use Thread.Abort()
  2. Tasks can be Cancelled but not aborted.

The Thread.Abort() method is (severely) deprecated.

Both Threads and Tasks should cooperate when being stopped, otherwise you run the risk of leaving the system in a unstable/undefined state.

If you do need to run a Process and kill it from the outside, the only safe option is to run it in a separate AppDomain.


This answer is about .net 3.5 and earlier.

Thread-abort handling has been improved since then, a.o. by changing the way finally blocks work.

But Thread.Abort is still a suspect solution that you should always try to avoid.

Reading CSV file and storing values into an array

My favourite CSV parser is one built into .NET library. This is a hidden treasure inside Microsoft.VisualBasic namespace. Below is a sample code:

using Microsoft.VisualBasic.FileIO;

var path = @"C:\Person.csv"; // Habeeb, "Dubai Media City, Dubai"
using (TextFieldParser csvParser = new TextFieldParser(path))
{
 csvParser.CommentTokens = new string[] { "#" };
 csvParser.SetDelimiters(new string[] { "," });
 csvParser.HasFieldsEnclosedInQuotes = true;

 // Skip the row with the column names
 csvParser.ReadLine();

 while (!csvParser.EndOfData)
 {
  // Read current line fields, pointer moves to the next line.
  string[] fields = csvParser.ReadFields();
  string Name = fields[0];
  string Address = fields[1];
 }
}

Remember to add reference to Microsoft.VisualBasic

More details about the parser is given here: http://codeskaters.blogspot.ae/2015/11/c-easiest-csv-parser-built-in-net.html

How do I fix the error "Only one usage of each socket address (protocol/network address/port) is normally permitted"?

You are debugging two or more times. so the application may run more at a time. Then only this issue will occur. You should close all debugging applications using task-manager, Then debug again.

How to create a remote Git repository from a local one?

There is an interesting difference between the two popular solutions above:

  1. If you create the bare repository like this:

    cd     /outside_of_any_repo
    mkdir  my_remote.git
    cd     my_remote.git
    git init --bare
    

and then

cd  /your_path/original_repo
git remote add origin /outside_of_any_repo/my_remote.git
git push --set-upstream origin master

Then git sets up the configuration in 'original_repo' with this relationship:

original_repo origin --> /outside_of_any_repo/my_remote.git/

with the latter as the upstream remote. And the upstream remote doesn't have any other remotes in its configuration.

  1. However, if you do it the other way around:

    (from in directory original_repo)
    cd ..
    git clone --bare original_repo  /outside_of_any_repo/my_remote.git
    

then 'my_remote.git' winds up with its configuration having 'origin' pointing back to 'original_repo' as a remote, with a remote.origin.url equating to local directory path, which might not be appropriate if it is going to be moved to a server.

While that "remote" reference is easy to get rid of later if it isn't appropriate, 'original_repo' still has to be set up to point to 'my_remote.git' as an up-stream remote (or to wherever it is going to be shared from). So technically, you can arrive at the same result with a few more steps with approach #2. But #1 seems a more direct approach to creating a "central bare shared repo" originating from a local one, appropriate for moving to a server, with fewer steps involved. I think it depends on the role you want the remote repo to play. (And yes, this is in conflict with the documentation here.)

Caveat: I learned the above (at this writing in early August 2019) by doing a test on my local system with a real repo, and then doing a file-by-file comparison between the results. But! I am still learning, so there could be a more correct way. But my tests have helped me conclude that #1 is my currently-preferred method.

System.MissingMethodException: Method not found?

Check your References!

Be sure that you are consistently pointing to the same 3rd party libraries (don't just trust versions, look at the path) across your solutions projects.

For example, If you use iTextSharp v.1.00.101 in one project and you NuGet or reference iTextSharp v1.00.102 somewhere else you will get these types of runtime errors that somehow trickle up into your code.

I changed my reference to iTextSharp in all 3 projects to point to the same DLL and everything worked.

C pointers and arrays: [Warning] assignment makes pointer from integer without a cast

What are you doing: (I am using bytes instead of in for better reading)

You start with int *ap and so on, so your (your computers) memory looks like this:

-------------- memory used by some one else --------
000: ?
001: ?
...
098: ?
099: ?
-------------- your memory  --------
100: something          <- here is *ap
101: 41                 <- here starts a[] 
102: 42
103: 43
104: 44
105: 45
106: something          <- here waits x

lets take a look waht happens when (print short cut for ...print("$d", ...)

print a[0]  -> 41   //no surprise
print a     -> 101  // because a points to the start of the array
print *a    -> 41   // again the first element of array
print a+1   -> guess? 102
print *(a+1)    -> whats behind 102? 42 (we all love this number)

and so on, so a[0] is the same as *a, a[1] = *(a+1), ....

a[n] just reads easier.

now, what happens at line 9?

ap=a[4] // we know a[4]=*(a+4) somehow *105 ==>  45 
// warning! converting int to pointer!
-------------- your memory  --------
100: 45         <- here is *ap now 45

x = *ap;   // wow ap is 45 -> where is 45 pointing to?
-------------- memory used by some one else --------
bang!      // dont touch neighbours garden

So the "warning" is not just a warning it's a severe error.

How to write multiple conditions in Makefile.am with "else if"

ifdef $(HAVE_CLIENT)
libtest_LIBS = \
    $(top_builddir)/libclient.la
else
ifdef $(HAVE_SERVER)
libtest_LIBS = \
    $(top_builddir)/libserver.la
else
libtest_LIBS = 
endif
endif

NOTE: DO NOT indent the if then it don't work!

Static array vs. dynamic array in C++

It's important to have clear definitions of what terms mean. Unfortunately there appears to be multiple definitions of what static and dynamic arrays mean.

Static variables are variables defined using static memory allocation. This is a general concept independent of C/C++. In C/C++ we can create static variables with global, file, or local scope like this:

int x[10]; //static array with global scope
static int y[10]; //static array with file scope
foo() {
    static int z[10]; //static array with local scope

Automatic variables are usually implemented using stack-based memory allocation. An automatic array can be created in C/C++ like this:

foo() {
    int w[10]; //automatic array

What these arrays , x, y, z, and w have in common is that the size for each of them is fixed and is defined at compile time.

One of the reasons that it's important to understand the distinction between an automatic array and a static array is that static storage is usually implemented in the data section (or BSS section) of an object file and the compiler can use absolute addresses to access the arrays which is impossible with stack-based storage.

What's usually meant by a dynamic array is not one that is resizeable but one implemented using dynamic memory allocation with a fixed size determined at run-time. In C++ this is done using the new operator.

foo() {
   int *d = new int[n]; //dynamically allocated array with size n     

But it's possible to create an automatic array with a fixes size defined at runtime using alloca:

foo() {
    int *s = (int*)alloca(n*sizeof(int))

For a true dynamic array one should use something like std::vector in C++ (or a variable length array in C).

What was meant for the assignment in the OP's question? I think it's clear that what was wanted was not a static or automatic array but one that either used dynamic memory allocation using the new operator or a non-fixed sized array using e.g. std::vector.

Define static method in source-file with declaration in header-file in C++

You don't need to have static in function definition

What does /p mean in set /p?

The /P switch allows you to set the value of a variable to a line of input entered by the user. Displays the specified promptString before reading the line of input. The promptString can be empty.

Two ways I've used it... first:

SET /P variable=

When batch file reaches this point (when left blank) it will halt and wait for user input. Input then becomes variable.

And second:

SET /P variable=<%temp%\filename.txt

Will set variable to contents (the first line) of the txt file. This method won't work unless the /P is included. Both tested on Windows 8.1 Pro, but it's the same on 7 and 10.