Programs & Examples On #Name length

What is the maximum length of a table name in Oracle?

On Oracle 12.2, you can use built-in constant, ORA_MAX_NAME_LEN, set to 128 bytes (as per 12.2) Prior to Oracle 12.1 max size was 30 bytes.

Maximum filename length in NTFS (Windows XP and Windows Vista)?

255 chars, though the complete path should not be longer than that as well. There is a nice table over at Wikipedia about this: http://en.wikipedia.org/wiki/Filename.

Appending the same string to a list of strings in Python

list2 = ['%sbar' % (x,) for x in list]

And don't use list as a name; it shadows the built-in type.

Codeigniter displays a blank page instead of error messages

This happens to me whenever I do autoload stuff in autoload.php like the 'database'

To resolve this, If you're using Windows OS

  1. Open your php.ini. Search and uncomment this line - extension=php_mysql.dll

    (Please also check If the PHP directive points to where your extensions is located.
    Mine is extension_dir = "C:\php-5.4.8-Win32-VC9-x86\ext")

  2. Restart Apache and refresh your page

Pandas Replace NaN with blank/empty string

If you are converting DataFrame to JSON, NaN will give error so best solution is in this use case is to replace NaN with None.
Here is how:

df1 = df.where((pd.notnull(df)), None)

Node.js throws "btoa is not defined" error

export const universalBtoa = str => {
  try {
    return btoa(str);
  } catch (err) {
    return Buffer.from(str).toString('base64');
  }
};

export const universalAtob = b64Encoded => {
  try {
    return atob(b64Encoded);
  } catch (err) {
    return Buffer.from(b64Encoded, 'base64').toString();
  }
};

Submit button doesn't work

I ran into this on a friend's HTML code and in his case, he was missing quotes.

For example:

<form action="formHandler.php" name="yourForm" id="theForm" method="post">    
<input type="text" name="fname" id="fname" style="width:90;font-size:10>     
<input type="submit" value="submit"/>
</form>

In this example, a missing quote on the input text fname will simply render the submit button un-usable and the form will not submit.

Of course, this is a bad example because I should be using CSS in the first place ;) but anyways, check all your single and double quotes to see that they are closing properly.

Also, if you have any tags like center, move them out of the form.

<form action="formHandler.php" name="yourForm" id="theForm" method="post">  
<center> <-- bad

As strange it may seems, it can have an impact.

Masking password input from the console : Java

A full example ?. Run this code : (NB: This example is best run in the console and not from within an IDE, since the System.console() method might return null in that case.)

import java.io.Console;
public class Main {

    public void passwordExample() {        
        Console console = System.console();
        if (console == null) {
            System.out.println("Couldn't get Console instance");
            System.exit(0);
        }

        console.printf("Testing password%n");
        char[] passwordArray = console.readPassword("Enter your secret password: ");
        console.printf("Password entered was: %s%n", new String(passwordArray));

    }

    public static void main(String[] args) {
        new Main().passwordExample();
    }
}

Difference between "and" and && in Ruby?

and is the same as && but with lower precedence. They both use short-circuit evaluation.

WARNING: and even has lower precedence than = so you'll usually want to avoid and. An example when and should be used can be found in the Rails Guide under "Avoiding Double Render Errors".

Importing .py files in Google Colab

Below are the steps that worked for me

  1. Mount your google drive in google colab

    from google.colab import drive drive.mount('/content/drive')

  2. Insert the directory

    import sys sys.path.insert(0,’/content/drive/My Drive/ColabNotebooks’)

  3. check the current directory path

    %cd drive/MyDrive/ColabNotebooks %pwd

  4. Import your module or file

    import my_module

  5. If you get the following error 'Name Null is not defined' then do the following

    5.1 Download my_module.ipynb from colab as my_module.py file (file->Download .py)

    5.2 Upload the *.py file to drive/MyDrive/ColabNotebooks in Google drive

    5.3 import my_module will work now

Reference: https://medium.com/analytics-vidhya/importing-your-own-python-module-or-python-file-into-colab-3e365f0a35ec

https://github.com/googlecolab/colabtools/issues/1358

assembly to compare two numbers

input password program
.modle small
.stack 100h
.data
s pasword db 34
input pasword db "enter pasword","$"
valid db ?
invalid db?
.code
mov ax, @ data 
mov db, ax
mov ah,09h
mov dx, offest s pasword
int 21h
mov ah, 01h
cmp al, s pasword
je v
jmp nv
v:
mov ah, 09h
mov dx, offset valid 
int 21h
nv:
mov ah, 09h
mov dx, offset invalid 
int 21h
mov ah, 04ch 
int 21
end 

Who is listening on a given TCP port on Mac OS X?

On the latest macOS version you can use this command:

lsof -nP -i4TCP:$PORT | grep LISTEN

If you find it hard to remember then maybe you should create a bash function and export it with a friendlier name like so

vi ~/.bash_profile

and then add the following lines to that file and save it.

function listening_on() {
    lsof -nP -i4TCP:"$1" | grep LISTEN
}

Now you can type listening_on 80 in your Terminal and see which process is listening on port 80.

What is the difference between pull and clone in git?

git clone means you are making a copy of the repository in your system.

git fork means you are copying the repository to your Github account.

git pull means you are fetching the last modified repository.

git push means you are returning the repository after modifying it.

In layman's term:

git clone is downloading and git pull is refreshing.

A potentially dangerous Request.Form value was detected from the client

In ASP.NET MVC (starting in version 3), you can add the AllowHtml attribute to a property on your model.

It allows a request to include HTML markup during model binding by skipping request validation for the property.

[AllowHtml]
public string Description { get; set; }

What is the best/safest way to reinstall Homebrew?

The way to reinstall Homebrew is completely remove it and start over. The Homebrew FAQ has a link to a shell script to uninstall homebrew.

If the only thing you've installed in /usr/local is homebrew itself, you can just rm -rf /usr/local/* /usr/local/.git to clear it out. But /usr/local/ is the standard Unix directory for all extra binaries, not just Homebrew, so you may have other things installed there. In that case uninstall_homebrew.sh is a better bet. It is careful to only remove homebrew's files and leave the rest alone.

How to control font sizes in pgf/tikz graphics in latex?

\begin{tikzpicture}
    \tikzstyle{every node}=[font=\fontsize{30}{30}\selectfont]
\end{tikzpicture}

How to perform Unwind segue programmatically?

SWIFT 4:

1. Create an @IBAction with segue inside controller you want to unwind to:

    @IBAction func unwindToVC(segue: UIStoryboardSegue) {

    }

2. In the storyboard, from the controller you want to segue (unwind) from ctrl+drag from the controller sign to exit sign and choose method you created earlier:

enter image description here

3. Now you can notice that in document outline you have new line with title "Unwind segue....". Now you should click on this line and open attribute inspector to set identifier (in my case unwindSegueIdentifier).

enter image description here

4. You're almost done! Now you need to open view controller you wish to unwind from and create some method that will perform segue. For example you can add button, connect it with code with @IBAction, after that inside this IBAction add perfromSegue(withIdentifier:sender:) method:

     @IBAction func unwindToSomeVCWithSegue(_ sender: UIButton) {
         performSegue(withIdentifier: "unwindSegueIdentifier", sender: nil)
     }

So that is all you have to do!

Difference Between $.getJSON() and $.ajax() in jQuery

There is lots of confusion in some of the function of jquery like $.ajax, $.get, $.post, $.getScript, $.getJSON that what is the difference among them which is the best, which is the fast, which to use and when so below is the description of them to make them clear and to get rid of this type of confusions.

$.getJSON() function is a shorthand Ajax function (internally use $.get() with data type script), which is equivalent to below expression, Uses some limited criteria like Request type is GET and data Type is json.

Read More .. jquery-post-vs-get-vs-ajax

Change the location of the ~ directory in a Windows install of Git Bash

So, $HOME is what I need to modify.

However I have been unable to find where this mythical $HOME variable is set so I assumed it was a Linux system version of PATH or something.

Git 2.23 (Q3 2019) is quite explicit on how HOME is set.

See commit e12a955 (04 Jul 2019) by Karsten Blees (kblees).
(Merged by Junio C Hamano -- gitster -- in commit fc613d2, 19 Jul 2019)

mingw: initialize HOME on startup

HOME initialization was historically duplicated in many different places, including /etc/profile, launch scripts such as git-bash.vbs and gitk.cmd, and (although slightly broken) in the git-wrapper.

Even unrelated projects such as GitExtensions and TortoiseGit need to implement the same logic to be able to call git directly.

Initialize HOME in Git's own startup code so that we can eventually retire all the duplicate initialization code.

Now, mingw.c includes the following code:

/* calculate HOME if not set */
if (!getenv("HOME")) {
    /*
     * try $HOMEDRIVE$HOMEPATH - the home share may be a network
     * location, thus also check if the path exists (i.e. is not
     * disconnected)
     */
    if ((tmp = getenv("HOMEDRIVE"))) {
        struct strbuf buf = STRBUF_INIT;
        strbuf_addstr(&buf, tmp);
        if ((tmp = getenv("HOMEPATH"))) {
            strbuf_addstr(&buf, tmp);
            if (is_directory(buf.buf))
                setenv("HOME", buf.buf, 1);
            else
                tmp = NULL; /* use $USERPROFILE */
        }
        strbuf_release(&buf);
    }
    /* use $USERPROFILE if the home share is not available */
    if (!tmp && (tmp = getenv("USERPROFILE")))
        setenv("HOME", tmp, 1);
}

HTML iframe - disable scroll

It seems to work using

html, body { overflow: hidden; }

inside the IFrame

edit: Of course this is only working, if you have access to the Iframe's content (which I have in my case)

Difference between "@id/" and "@+id/" in Android

Android uses some files called resources where values are stored for the XML files.

Now when you use @id/ for an XML object, It is trying to refer to an id which is already registered in the values files. On the other hand, when you use @+id/ it registers a new id in the values files as implied by the '+' symbol.

Hope this helps :).

Setting graph figure size

 figure (1)
 hFig = figure(1);
 set(gcf,'PaperPositionMode','auto')
 set(hFig, 'Position', [0 0 xwidth ywidth])
 plot(x,y)
 print -depsc2 correlation.eps;       % for saving in eps, look up options for saving as png or other formats you may need

This saves the figure in the dimensions specified

What does the term "canonical form" or "canonical representation" in Java mean?

The word "canonical" is just a synonym for "standard" or "usual". It doesn`t have any Java-specific meaning.

Check difference in seconds between two times

This version always returns the number of seconds difference as a positive number (same result as @freedeveloper's solution):

var seconds = System.Math.Abs((date1 - date2).TotalSeconds);

Change the value in app.config file dynamically

 XmlReaderSettings _configsettings = new XmlReaderSettings();
 _configsettings.IgnoreComments = true;

 XmlReader _configreader = XmlReader.Create(ConfigFilePath, _configsettings);
 XmlDocument doc_config = new XmlDocument();
 doc_config.Load(_configreader);
 _configreader.Close();

 foreach (XmlNode RootName in doc_config.DocumentElement.ChildNodes)
 {
     if (RootName.LocalName == "appSettings")
     {
         if (RootName.HasChildNodes)
         {
             foreach (XmlNode _child in RootName.ChildNodes)
             {
                 if (_child.Attributes["key"].Value == "HostName")
                 {
                     if (_child.Attributes["value"].Value == "false")
                         _child.Attributes["value"].Value = "true";
                 }
             }
         }
     }
 }
 doc_config.Save(ConfigFilePath);

Entity Framework - Include Multiple Levels of Properties

For EF 6

using System.Data.Entity;

query.Include(x => x.Collection.Select(y => y.Property))

Make sure to add using System.Data.Entity; to get the version of Include that takes in a lambda.


For EF Core

Use the new method ThenInclude

query.Include(x => x.Collection)
     .ThenInclude(x => x.Property);

Pretty Printing a pandas dataframe

I used Ofer's answer for a while and found it great in most cases. Unfortunately, due to inconsistencies between pandas's to_csv and prettytable's from_csv, I had to use prettytable in a different way.

One failure case is a dataframe containing commas:

pd.DataFrame({'A': [1, 2], 'B': ['a,', 'b']})

Prettytable raises an error of the form:

Error: Could not determine delimiter

The following function handles this case:

def format_for_print(df):    
    table = PrettyTable([''] + list(df.columns))
    for row in df.itertuples():
        table.add_row(row)
    return str(table)

If you don't care about the index, use:

def format_for_print2(df):    
    table = PrettyTable(list(df.columns))
    for row in df.itertuples():
        table.add_row(row[1:])
    return str(table)

MySQL vs MySQLi when using PHP

If you have a look at MySQL Improved Extension Overview, it should tell you everything you need to know about the differences between the two.

The main useful features are:

  • an Object-oriented interface
  • support for prepared statements
  • support for multiple statements
  • support for transactions
  • enhanced debugging capabilities
  • embedded server support.

Check if string contains a value in array

You are not using the function in_array (http://php.net/manual/en/function.in-array.php) correctly:

bool in_array ( mixed $needle , array $haystack [, bool $strict = FALSE ] )

The $needle has to have a value in the array, so you first need to extract the url from the string (with a regular expression for example). Something like this:

$url = extrctUrl('my domain name is website3.com');
//$url will be 'website3.com'
in_array($url, $owned_urls)

Intellij reformat on file save

Ctrl + Alt + L is format file (includes the two below)

Ctrl + Alt + O is optimize imports

Ctrl + Alt + I will fix indentation on a particular line

I usually run Ctrl + Alt + L a few times before committing my work. I'd rather it do the cleanup/reformatting at my command instead of automatically.

How do I get a class instance of generic type T?

That is pretty straight forward. If you need from within the same class:

Class clazz = this.getClass();
ParameterizedType parameterizedType = (ParameterizedType) clazz.getGenericSuperclass();
try {
        Class typeClass = Class.forName( parameterizedType.getActualTypeArguments()[0].getTypeName() );
        // You have the instance of type 'T' in typeClass variable

        System.out.println( "Class instance name: "+  typeClass.getName() );
    } catch (ClassNotFoundException e) {
        System.out.println( "ClassNotFound!! Something wrong! "+ e.getMessage() );
    }

maven compilation failure

My guess is a wrong version of project A jar in your local maven repository. It seems that the dependency is resolved otherwise I think maven does not start compiling but usually these compiling error means that you have a version mix up. try to make a maven clean install of your project A and see if it changes something for the project B... Also a little more information on your setting could be useful:

  • How is maven launched? what command? on a shell, an IDE (using a plugin or not), on a CI server?
  • What maven command are you using?

Disable button in jQuery

For Jquery UI buttons this works :

$("#buttonId").button( "option", "disabled", true | false );

Tainted canvases may not be exported

Just as a build on @markE's answer—if you want to create a local server. You won't have this error on a local server.

If you have PHP installed on your computer:

  1. Open up your terminal/cmd
  2. Navigate into the folder where your website files are
  3. While in this folder, run the command php -S localhost:3000 ? Notice the capital 'S'
  4. Open up your browser and in the URL bar go to localhost:3000. Your website should be running there.

or

If you have Node.js installed on your computer:

  1. Open up your terminal/cmd
  2. Navigate into the folder where your website files are
  3. While in this folder, run the command npm init -y
  4. Run npm install live-server -g or sudo npm install live-server -g on a mac
  5. Run live-server and it should automatically open up a new tab in the browser with your website open.

Note: remember to have an index.html file in the root of your folder or else you might have some issues.

Combine two or more columns in a dataframe into a new column with a new name

For inserting a separator:

df$x <- paste(df$n, "-", df$s)

Mocking HttpClient in unit tests

Inspired by PointZeroTwo's answer, here's a sample using NUnit and FakeItEasy.

SystemUnderTest in this example is the class that you want to test - no sample content given for it but I assume you have that already!

[TestFixture]
public class HttpClientTests
{
    private ISystemUnderTest _systemUnderTest;
    private HttpMessageHandler _mockMessageHandler;

    [SetUp]
    public void Setup()
    {
        _mockMessageHandler = A.Fake<HttpMessageHandler>();
        var httpClient = new HttpClient(_mockMessageHandler);

        _systemUnderTest = new SystemUnderTest(httpClient);
    }

    [Test]
    public void HttpError()
    {
        // Arrange
        A.CallTo(_mockMessageHandler)
            .Where(x => x.Method.Name == "SendAsync")
            .WithReturnType<Task<HttpResponseMessage>>()
            .Returns(Task.FromResult(new HttpResponseMessage
            {
                StatusCode = HttpStatusCode.InternalServerError,
                Content = new StringContent("abcd")
            }));

        // Act
        var result = _systemUnderTest.DoSomething();

        // Assert
        // Assert.AreEqual(...);
    }
}

Paste Excel range in Outlook

First off, RangeToHTML. The script calls it like a method, but it isn't. It's a popular function by MVP Ron de Bruin. Coincidentally, that links points to the exact source of the script you posted, before those few lines got b?u?t?c?h?e?r?e?d? modified.

On with Range.SpecialCells. This method operates on a range and returns only those cells that match the given criteria. In your case, you seem to be only interested in the visible text cells. Importantly, it operates on a Range, not on HTML text.

For completeness sake, I'll post a working version of the script below. I'd certainly advise to disregard it and revisit the excellent original by Ron the Bruin.

Sub Mail_Selection_Range_Outlook_Body()

Dim rng As Range
Dim OutApp As Object
Dim OutMail As Object

Set rng = Nothing
' Only send the visible cells in the selection.

Set rng = Sheets("Sheet1").Range("D4:D12").SpecialCells(xlCellTypeVisible)

If rng Is Nothing Then
    MsgBox "The selection is not a range or the sheet is protected. " & _
           vbNewLine & "Please correct and try again.", vbOKOnly
    Exit Sub
End If

With Application
    .EnableEvents = False
    .ScreenUpdating = False
End With

Set OutApp = CreateObject("Outlook.Application")
Set OutMail = OutApp.CreateItem(0)


With OutMail
    .To = ThisWorkbook.Sheets("Sheet2").Range("C1").Value
    .CC = ""
    .BCC = ""
    .Subject = "This is the Subject line"
    .HTMLBody = RangetoHTML(rng)
    ' In place of the following statement, you can use ".Display" to
    ' display the e-mail message.
    .Display
End With
On Error GoTo 0

With Application
    .EnableEvents = True
    .ScreenUpdating = True
End With

Set OutMail = Nothing
Set OutApp = Nothing
End Sub


Function RangetoHTML(rng As Range)
' By Ron de Bruin.
    Dim fso As Object
    Dim ts As Object
    Dim TempFile As String
    Dim TempWB As Workbook

    TempFile = Environ$("temp") & "/" & Format(Now, "dd-mm-yy h-mm-ss") & ".htm"

    'Copy the range and create a new workbook to past the data in
    rng.Copy
    Set TempWB = Workbooks.Add(1)
    With TempWB.Sheets(1)
        .Cells(1).PasteSpecial Paste:=8
        .Cells(1).PasteSpecial xlPasteValues, , False, False
        .Cells(1).PasteSpecial xlPasteFormats, , False, False
        .Cells(1).Select
        Application.CutCopyMode = False
        On Error Resume Next
        .DrawingObjects.Visible = True
        .DrawingObjects.Delete
        On Error GoTo 0
    End With

    'Publish the sheet to a htm file
    With TempWB.PublishObjects.Add( _
         SourceType:=xlSourceRange, _
         Filename:=TempFile, _
         Sheet:=TempWB.Sheets(1).Name, _
         Source:=TempWB.Sheets(1).UsedRange.Address, _
         HtmlType:=xlHtmlStatic)
        .Publish (True)
    End With

    'Read all data from the htm file into RangetoHTML
    Set fso = CreateObject("Scripting.FileSystemObject")
    Set ts = fso.GetFile(TempFile).OpenAsTextStream(1, -2)
    RangetoHTML = ts.ReadAll
    ts.Close
    RangetoHTML = Replace(RangetoHTML, "align=center x:publishsource=", _
                          "align=left x:publishsource=")

    'Close TempWB
    TempWB.Close savechanges:=False

    'Delete the htm file we used in this function
    Kill TempFile

    Set ts = Nothing
    Set fso = Nothing
    Set TempWB = Nothing
End Function

How to increase the Java stack size?

It is hard to give a sensible solution since you are keen to avoid all sane approaches. Refactoring one line of code is the senible solution.

Note: Using -Xss sets the stack size of every thread and is a very bad idea.

Another approach is byte code manipulation to change the code as follows;

public static long fact(int n) { 
    return n < 2 ? n : n > 127 ? 0 : n * fact(n - 1); 
}

given every answer for n > 127 is 0. This avoid changing the source code.

SQLite Query in Android to count rows

int nombr = 0;
Cursor cursor = sqlDatabase.rawQuery("SELECT column FROM table WHERE column = Value", null);
nombr = cursor.getCount();

PHP Parse error: syntax error, unexpected T_PUBLIC

The public keyword is used only when declaring a class method.

Since you're declaring a simple function and not a class you need to remove public from your code.

Change header text of columns in a GridView

You can do it with gridview's datarow bound event. try the following sample of code:

protected void grv_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.Header)
{
e.Row.Cells[0].Text = "TiTle";
}
}

For more details about the row databound event study Thsi....

Replace negative values in an numpy array

Try numpy.clip:

>>> import numpy
>>> a = numpy.arange(-10, 10)
>>> a
array([-10,  -9,  -8,  -7,  -6,  -5,  -4,  -3,  -2,  -1,   0,   1,   2,
         3,   4,   5,   6,   7,   8,   9])
>>> a.clip(0, 10)
array([0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9])

You can clip only the bottom half with clip(0).

>>> a = numpy.array([1, 2, 3, -4, 5])
>>> a.clip(0)
array([1, 2, 3, 0, 5])

You can clip only the top half with clip(max=n). (This is much better than my previous suggestion, which involved passing NaN to the first parameter and using out to coerce the type.):

>>> a.clip(max=2)
array([ 1,  2,  2, -4,  2])

Another interesting approach is to use where:

>>> numpy.where(a <= 2, a, 2)
array([ 1,  2,  2, -4,  2])

Finally, consider aix's answer. I prefer clip for simple operations because it's self-documenting, but his answer is preferable for more complex operations.

Enable vertical scrolling on textarea

Simply, change

<textarea rows="15" cols="50" id="aboutDescription"
style="resize: none;"></textarea>

to

<textarea rows="15" cols="50" id="aboutDescription"
style="resize: none;" data-role="none"></textarea>

ie, add:

data-role="none"

python: Change the scripts working directory to the script's own directory

Don't do this.

Your scripts and your data should not be mashed into one big directory. Put your code in some known location (site-packages or /var/opt/udi or something) separate from your data. Use good version control on your code to be sure that you have current and previous versions separated from each other so you can fall back to previous versions and test future versions.

Bottom line: Do not mingle code and data.

Data is precious. Code comes and goes.

Provide the working directory as a command-line argument value. You can provide a default as an environment variable. Don't deduce it (or guess at it)

Make it a required argument value and do this.

import sys
import os
working= os.environ.get("WORKING_DIRECTORY","/some/default")
if len(sys.argv) > 1: working = sys.argv[1]
os.chdir( working )

Do not "assume" a directory based on the location of your software. It will not work out well in the long run.

if condition in sql server update query

Something like this should work:

UPDATE
    table_Name
SET 
  column_A = CASE WHEN @flag = '1' THEN column_A + @new_value ELSE column_A END,
  column_B = CASE WHEN @flag = '0' THEN column_B + @new_value ELSE column_B END
WHERE
    ID = @ID

Changing the background color of a drop down list transparent in html

You can actualy fake the transparency of option DOMElements with the following CSS:

CSS

option { 
    /* Whatever color  you want */
    background-color: #82caff;
}

See Demo

The option tag does not support rgba colors yet.

"’" showing on page instead of " ' "

In DBeaver (or other editors) the script file you're working can prompt to save as UTF8 and that will change the char:

–

into

–

or

–

How to count the number of files in a directory using Python

If you want to count all files in the directory - including files in subdirectories, the most pythonic way is:

import os

file_count = sum(len(files) for _, _, files in os.walk(r'C:\Dropbox'))
print(file_count)

We use sum that is faster than explicitly adding the file counts (timings pending)

"cannot be used as a function error"

This line is the problem:

int estimatedPopulation (int currentPopulation,
                         float growthRate (birthRate, deathRate))

Make it:

int estimatedPopulation (int currentPopulation, float birthRate, float deathRate)

instead and invoke the function with three arguments like

estimatePopulation( currentPopulation, birthRate, deathRate );

OR declare it with two arguments like:

int estimatedPopulation (int currentPopulation, float growthrt ) { ... }

and call it as

estimatedPopulation( currentPopulation, growthRate (birthRate, deathRate));

Edit:

Probably more important here - C++ (and C) names have scope. You can have two things named the same but not at the same time. In your particular case your grouthRate variable in the main() hides the function with the same name. So within main() you can only access grouthRate as float. On the other hand, outside of the main() you can only access that name as a function, since that automatic variable is only visible within the scope of main().

Just hope I didn't confuse you further :)

Convert JavaScript String to be all lower case?

Opt 1: using toLowerCase()

var x = 'ABC';
x = x.toLowerCase();

Opt 2: Using your own function

function convertToLowerCase(str) {
  var result = '';

  for (var i = 0; i < str.length; i++) {
    var code = str.charCodeAt(i);
    if (code > 64 && code < 91) {
      result += String.fromCharCode(code + 32);
    } else {
      result += str.charAt(i);
    }
  }
  return result;
}

Call it as:

x = convertToLowerCase(x);

Why does only the first line of this Windows batch file execute but all three lines execute in a command shell?

Maven uses batch files to do its business. With any batch script, you must call another script using the call command so it knows to return back to your script after the called script completes. Try prepending call to all commands.

Another thing you could try is using the start command which should work similarly.

jQuery Datepicker onchange event issue

I think your problem may lie in how your datepicker is setup. Why don't you disconnect the input... do not use altField. Instead explicitly set the values when the onSelect fires. This will give you control of each interaction; the user text field, and the datepicker.

Note: Sometimes you have to call the routine on .change() and not .onSelect() because onSelect can be called on different interactions that you are not expecting.

Pseudo Code:

$('#date').datepicker({
    //altField: , //do not use
    onSelect: function(date){
        $('#date').val(date); //Set my textbox value
        //Do your search routine
    },
}).change(function(){
    //Or do it here...
});

$('#date').change(function(){
    var thisDate = $(this).val();
    if(isValidDate(thisDate)){
        $('#date').datepicker('setDate', thisDate); //Set my datepicker value
        //Do your search routine
    });
});

How to get Url Hash (#) from server side

RFC 2396 section 4.1:

When a URI reference is used to perform a retrieval action on the identified resource, the optional fragment identifier, separated from the URI by a crosshatch ("#") character, consists of additional reference information to be interpreted by the user agent after the retrieval action has been successfully completed. As such, it is not part of a URI, but is often used in conjunction with a URI.

(emphasis added)

Is there a way to remove unused imports and declarations from Angular 2+?

As of Visual Studio Code Release 1.22 this comes free without the need of an extension.

Shift+Alt+O will take care of you.

How do I shutdown, restart, or log off Windows via a bat file?

If you are on a remote machine, you may also want to add the -f option to force the reboot. Otherwise your session may close and a stubborn app can hang the system.

I use this whenever I want to force an immediate reboot:

shutdown -t 0 -r -f

For a more friendly "give them some time" option, you can use this:

shutdown -t 30 -r

As you can see in the comments, the -f is implied by the timeout.

Brutus 2006 is a utility that provides a GUI for these options.

Reading NFC Tags with iPhone 6 / iOS 8

I think it will be sometime before we get to see access to the NFC as the pure security side of it like for example being able to walk past somebody brush past them and & get your phone to the zap the card details or simply Wave your phone over someone's wallet which They left on the desk.

I think the first step is for Apple to talk to banks and find more ways of securing cards and NFC before This will be allowed

Calculate AUC in R?

Without any additional packages:

true_Y = c(1,1,1,1,2,1,2,1,2,2)
probs = c(1,0.999,0.999,0.973,0.568,0.421,0.382,0.377,0.146,0.11)

getROC_AUC = function(probs, true_Y){
    probsSort = sort(probs, decreasing = TRUE, index.return = TRUE)
    val = unlist(probsSort$x)
    idx = unlist(probsSort$ix)  

    roc_y = true_Y[idx];
    stack_x = cumsum(roc_y == 2)/sum(roc_y == 2)
    stack_y = cumsum(roc_y == 1)/sum(roc_y == 1)    

    auc = sum((stack_x[2:length(roc_y)]-stack_x[1:length(roc_y)-1])*stack_y[2:length(roc_y)])
    return(list(stack_x=stack_x, stack_y=stack_y, auc=auc))
}

aList = getROC_AUC(probs, true_Y) 

stack_x = unlist(aList$stack_x)
stack_y = unlist(aList$stack_y)
auc = unlist(aList$auc)

plot(stack_x, stack_y, type = "l", col = "blue", xlab = "False Positive Rate", ylab = "True Positive Rate", main = "ROC")
axis(1, seq(0.0,1.0,0.1))
axis(2, seq(0.0,1.0,0.1))
abline(h=seq(0.0,1.0,0.1), v=seq(0.0,1.0,0.1), col="gray", lty=3)
legend(0.7, 0.3, sprintf("%3.3f",auc), lty=c(1,1), lwd=c(2.5,2.5), col="blue", title = "AUC")

enter image description here

How to go from one page to another page using javascript?

The correct solution that i get is

<html>
      <head>
        <script type="text/javascript" language="JavaScript">
                  function clickedButton()
            {

                window.location = 'new url'

            }
             </script>
      </head>

      <form name="login_form" method="post">
            ..................
            <input type="button" value="Login" onClick="clickedButton()"/>
      </form>
 </html>

Here the new url is given inside the single quote.

How to retrieve raw post data from HttpServletRequest in java

The request body is available as byte stream by HttpServletRequest#getInputStream():

InputStream body = request.getInputStream();
// ...

Or as character stream by HttpServletRequest#getReader():

Reader body = request.getReader();
// ...

Note that you can read it only once. The client ain't going to resend the same request multiple times. Calling getParameter() and so on will implicitly also read it. If you need to break down parameters later on, you've got to store the body somewhere and process yourself.

Java: Add elements to arraylist with FOR loop where element name has increasing number

why you need a for-loop for this? the solution is very obvious:

answers.add(answer1);
answers.add(answer2);
answers.add(answer3);

that's it. no for-loop needed.

Fatal error compiling: invalid target release: 1.8 -> [Help 1]

Put the value in the plugin:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.1</version>
    <configuration>
        <source>1.8</source>
        <target>1.8</target>
    </configuration>
</plugin>

The error was use:

<source>${java.version}</source>
<target>${java.version}</target>

java Arrays.sort 2d array

Java 8 is now very common nowadays.

Arrays.sort(myArr,(double[] a,double[] b)->{
                //here multiple lines of code can be placed
                return a[0]-b[0]; 
            });

Phone validation regex

Please refer to this SO Post

example of a regular expression in jquery for phone numbers

/\(?([0-9]{3})\)?([ .-]?)([0-9]{3})\2([0-9]{4})/
  • (123) 456 7899
  • (123).456.7899
  • (123)-456-7899
  • 123-456-7899
  • 123 456 7899
  • 1234567899

are supported

How to create a GUID/UUID in Python

I use GUIDs as random keys for database type operations.

The hexadecimal form, with the dashes and extra characters seem unnecessarily long to me. But I also like that strings representing hexadecimal numbers are very safe in that they do not contain characters that can cause problems in some situations such as '+','=', etc..

Instead of hexadecimal, I use a url-safe base64 string. The following does not conform to any UUID/GUID spec though (other than having the required amount of randomness).

import base64
import uuid

# get a UUID - URL safe, Base64
def get_a_uuid():
    r_uuid = base64.urlsafe_b64encode(uuid.uuid4().bytes)
    return r_uuid.replace('=', '')

How can I detect when the mouse leaves the window?

I tried one after other and found a best answer at the time:

https://stackoverflow.com/a/3187524/985399

I skip old browsers so I made the code shorter to work on modern browsers (IE9+)

_x000D_
_x000D_
    document.addEventListener("mouseout", function(e) {_x000D_
        let t = e.relatedTarget || e.toElement;_x000D_
        if (!t || t.nodeName == "HTML") {_x000D_
          console.log("left window");_x000D_
        }_x000D_
    });_x000D_
_x000D_
document.write("<br><br>PROBLEM<br><br><div>Mouseout trigg on HTML elements</div>")
_x000D_
_x000D_
_x000D_

Here you see the browser support

That was pretty short I thought

But a problem still remained because "mouseout" trigg on all elements in the document.

To prevent it from happen, use mouseleave (IE5.5+). See the good explanation in the link.

The following code works without triggering on elements inside the element to be inside or outside of. Try also drag-release outside the document.

_x000D_
_x000D_
var x = 0_x000D_
_x000D_
document.addEventListener("mouseleave", function(e) { console.log(x++) _x000D_
})_x000D_
_x000D_
document.write("<br><br>SOLUTION<br><br><div>Mouseleave do not trigg on HTML elements</div>")
_x000D_
_x000D_
_x000D_

You can set the event on any HTML element. Do not have the event on document.body though, because the windows scrollbar may shrink the body and fire when mouse pointer is abowe the scroll bar when you want to scroll but not want to trigg a mouseLeave event over it. Set it on document instead, as in the example.

Rendering React Components from Array of Objects

This is quite likely the simplest way to achieve what you are looking for.

In order to use this map function in this instance, we will have to pass a currentValue (always-required) parameter, as well an index (optional) parameter. In the below example, station is our currentValue, and x is our index.

station represents the current value of the object within the array as it is iterated over. x automatically increments; increasing by one each time a new object is mapped.

render () {
    return (
        <div>
            {stations.map((station, x) => (
                <div key={x}> {station} </div>
            ))}
        </div>
    );
}

What Thomas Valadez had answered, while it had provided the best/simplest method to render a component from an array of objects, it had failed to properly address the way in which you would assign a key during this process.

The preferred way of creating a new element with jQuery

If #box is empty, nothing, but if it's not these do very different things. The former will add a div as the last child node of #box. The latter completely replaces the contents of #box with a single empty div, text and all.

how to configuring a xampp web server for different root directory

You can change the port while you open your XAMP control panel, follow the steps:

  1. click on config net to the start button, and
  2. select httpd.conf, a text file will open
  3. check the file and file listen:80,
  4. once got listen:80 replace with listen:8080 and
  5. save in the same folder.

Once done that, you will be able to start your local server.

jQuery AJAX Call to PHP Script with JSON Return

I recommend you use:

var returnedData = JSON.parse(data);

to convert the JSON string (if it is just text) to a JavaScript object.

What is the significance of 1/1/1753 in SQL Server?

This is whole story how date problem was and how Big DBMSs handled these problems.

During the period between 1 A.D. and today, the Western world has actually used two main calendars: the Julian calendar of Julius Caesar and the Gregorian calendar of Pope Gregory XIII. The two calendars differ with respect to only one rule: the rule for deciding what a leap year is. In the Julian calendar, all years divisible by four are leap years. In the Gregorian calendar, all years divisible by four are leap years, except that years divisible by 100 (but not divisible by 400) are not leap years. Thus, the years 1700, 1800, and 1900 are leap years in the Julian calendar but not in the Gregorian calendar, while the years 1600 and 2000 are leap years in both calendars.

When Pope Gregory XIII introduced his calendar in 1582, he also directed that the days between October 4, 1582, and October 15, 1582, should be skipped—that is, he said that the day after October 4 should be October 15. Many countries delayed changing over, though. England and her colonies didn't switch from Julian to Gregorian reckoning until 1752, so for them, the skipped dates were between September 4 and September 14, 1752. Other countries switched at other times, but 1582 and 1752 are the relevant dates for the DBMSs that we're discussing.

Thus, two problems arise with date arithmetic when one goes back many years. The first is, should leap years before the switch be calculated according to the Julian or the Gregorian rules? The second problem is, when and how should the skipped days be handled?

This is how the Big DBMSs handle these questions:

  • Pretend there was no switch. This is what the SQL Standard seems to require, although the standard document is unclear: It just says that dates are "constrained by the natural rules for dates using the Gregorian calendar"—whatever "natural rules" are. This is the option that DB2 chose. When there is a pretence that a single calendar's rules have always applied even to times when nobody heard of the calendar, the technical term is that a "proleptic" calendar is in force. So, for example, we could say that DB2 follows a proleptic Gregorian calendar.
  • Avoid the problem entirely. Microsoft and Sybase set their minimum date values at January 1, 1753, safely past the time that America switched calendars. This is defendable, but from time to time complaints surface that these two DBMSs lack a useful functionality that the other DBMSs have and that the SQL Standard requires.
  • Pick 1582. This is what Oracle did. An Oracle user would find that the date-arithmetic expression October 15 1582 minus October 4 1582 yields a value of 1 day (because October 5–14 don't exist) and that the date February 29 1300 is valid (because the Julian leap-year rule applies). Why did Oracle go to extra trouble when the SQL Standard doesn't seem to require it? The answer is that users might require it. Historians and astronomers use this hybrid system instead of a proleptic Gregorian calendar. (This is also the default option that Sun picked when implementing the GregorianCalendar class for Java—despite the name, GregorianCalendar is a hybrid calendar.)

Source 1 and 2

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

def search(itemID,list):
     return[i for i in list if i.itemID==itemID]

Working with Enums in android

Where on earth did you find this syntax? Java Enums are very simple, you just specify the values.

public enum Gender {
   MALE,
   FEMALE
}

If you want them to be more complex, you can add values to them like this.

public enum Gender {
    MALE("Male", 0),
    FEMALE("Female", 1);

    private String stringValue;
    private int intValue;
    private Gender(String toString, int value) {
        stringValue = toString;
        intValue = value;
    }

    @Override
    public String toString() {
        return stringValue;
    }
}

Then to use the enum, you would do something like this:

Gender me = Gender.MALE

Adjust table column width to content size

maybe problem with margin?

width:auto;
padding: 0px;
margin: 0px

How to calculate time elapsed in bash script?

I realize this is an older post, but I came it across it today while working on a script that would take dates and times from a log file and compute the delta. The script below is certainly overkill, and I highly recommend checking my logic and maths.

#!/bin/bash

dTime=""
tmp=""

#firstEntry="$(head -n 1 "$LOG" | sed 's/.*] \([0-9: -]\+\).*/\1/')"
firstEntry="2013-01-16 01:56:37"
#lastEntry="$(tac "$LOG" | head -n 1 | sed 's/.*] \([0-9: -]\+\).*/\1/')"
lastEntry="2014-09-17 18:24:02"

# I like to make the variables easier to parse
firstEntry="${firstEntry//-/ }"
lastEntry="${lastEntry//-/ }"
firstEntry="${firstEntry//:/ }"
lastEntry="${lastEntry//:/ }"

# remove the following lines in production
echo "$lastEntry"
echo "$firstEntry"

# compute days in last entry
for i in `seq 1 $(echo $lastEntry|awk '{print $2}')`; do {
  case "$i" in
   1|3|5|7|8|10|12 )
    dTime=$(($dTime+31))
    ;;
   4|6|9|11 )
    dTime=$(($dTime+30))
    ;;
   2 )
    dTime=$(($dTime+28))
    ;;
  esac
} done

# do leap year calculations for all years between first and last entry
for i in `seq $(echo $firstEntry|awk '{print $1}') $(echo $lastEntry|awk '{print $1}')`; do {
  if [ $(($i%4)) -eq 0 ] && [ $(($i%100)) -eq 0 ] && [ $(($i%400)) -eq 0 ]; then {
    if [ "$i" = "$(echo $firstEntry|awk '{print $1}')" ] && [ $(echo $firstEntry|awk '{print $2}') -lt 2 ]; then {
      dTime=$(($dTime+1))
    } elif [ $(echo $firstEntry|awk '{print $2}') -eq 2 ] && [ $(echo $firstEntry|awk '{print $3}') -lt 29 ]; then {
      dTime=$(($dTime+1))
    } fi
  } elif [ $(($i%4)) -eq 0 ] && [ $(($i%100)) -ne 0 ]; then {
    if [ "$i" = "$(echo $lastEntry|awk '{print $1}')" ] && [ $(echo $lastEntry|awk '{print $2}') -gt 2 ]; then {
      dTime=$(($dTime+1))
    } elif [ $(echo $lastEntry|awk '{print $2}') -eq 2 ] && [ $(echo $lastEntry|awk '{print $3}') -ne 29 ]; then {
      dTime=$(($dTime+1))
    } fi
  } fi
} done

# substract days in first entry
for i in `seq 1 $(echo $firstEntry|awk '{print $2}')`; do {
  case "$i" in
   1|3|5|7|8|10|12 )
    dTime=$(($dTime-31))
    ;;
   4|6|9|11 )
    dTime=$(($dTime-30))
    ;;
   2 )
    dTime=$(($dTime-28))
    ;;
  esac
} done

dTime=$(($dTime+$(echo $lastEntry|awk '{print $3}')-$(echo $firstEntry|awk '{print $3}')))

# The above gives number of days for sample. Now we need hours, minutes, and seconds
# As a bit of hackery I just put the stuff in the best order for use in a for loop
dTime="$(($(echo $lastEntry|awk '{print $6}')-$(echo $firstEntry|awk '{print $6}'))) $(($(echo $lastEntry|awk '{print $5}')-$(echo $firstEntry|awk '{print $5}'))) $(($(echo $lastEntry|awk '{print $4}')-$(echo $firstEntry|awk '{print $4}'))) $dTime"
tmp=1
for i in $dTime; do {
  if [ $i -lt 0 ]; then {
    case "$tmp" in
     1 )
      tmp="$(($(echo $dTime|awk '{print $1}')+60)) $(($(echo $dTime|awk '{print $2}')-1))"
      dTime="$tmp $(echo $dTime|awk '{print $3" "$4}')"
      tmp=1
      ;;
     2 )
      tmp="$(($(echo $dTime|awk '{print $2}')+60)) $(($(echo $dTime|awk '{print $3}')-1))"
      dTime="$(echo $dTime|awk '{print $1}') $tmp $(echo $dTime|awk '{print $4}')"
      tmp=2
      ;;
     3 )
      tmp="$(($(echo $dTime|awk '{print $3}')+24)) $(($(echo $dTime|awk '{print $4}')-1))"
      dTime="$(echo $dTime|awk '{print $1" "$2}') $tmp"
      tmp=3
      ;;
    esac
  } fi
  tmp=$(($tmp+1))
} done

echo "The sample time is $(echo $dTime|awk '{print $4}') days, $(echo $dTime|awk '{print $3}') hours, $(echo $dTime|awk '{print $2}') minutes, and $(echo $dTime|awk '{print $1}') seconds."

You will get output as follows.

2012 10 16 01 56 37
2014 09 17 18 24 02
The sample time is 700 days, 16 hours, 27 minutes, and 25 seconds.

I modified the script a bit to make it standalone (ie. just set variable values), but maybe the general idea comes across as well. You'd might want some additional error checking for negative values.

Error: TypeError: $(...).dialog is not a function

I just experienced this with the line:

$('<div id="editor" />').dialogelfinder({

I got the error "dialogelfinder is not a function" because another component was inserting a call to load an older version of JQuery (1.7.2) after the newer version was loaded.

As soon as I commented out the second load, the error went away.

Read file from resources folder in Spring Boot

Below is my working code.

List<sampleObject> list = new ArrayList<>();
File file = new ClassPathResource("json/test.json").getFile();
ObjectMapper objectMapper = new ObjectMapper();
sampleObject = Arrays.asList(objectMapper.readValue(file, sampleObject[].class));

Hope it helps one!

Change the selected value of a drop-down list with jQuery

How are you loading the values into the drop down list or determining which value to select? If you are doing this using Ajax, then the reason you need the delay before the selection occurs could be because the values were not loaded in at the time that the line in question executed. This would also explain why it worked when you put an alert statement on the line before setting the status since the alert action would give enough of a delay for the data to load.

If you are using one of jQuery's Ajax methods, you can specify a callback function and then put $("._statusDDL").val(2); into your callback function.

This would be a more reliable way of handling the issue since you could be sure that the method executed when the data was ready, even if it took longer than 300 ms.

Spring Hibernate - Could not obtain transaction-synchronized Session for current thread

I encountered the same problem and finally found out that the <tx:annotaion-driven /> was not defined within the [dispatcher]-servlet.xml where component-scan element enabled @service annotated class.

Simply put <tx:annotaion-driven /> with component-scan element together, the problem disappeared.

Android Gradle Could not reserve enough space for object heap

Faced this issue on Android studio 4.1, windows 10.

The solution that worked for me:

1 - Go to gradle.properties file which is in the root directory of the project.

2 - Comment this line or similar one (org.gradle.jvmargs=-Xmx1536m) to let android studio decide on the best compatible option.

3 - Now close any open project from File -> close project.

4 - On the Welcome window, Go to Configure > Settings.

5 - Go to Build, Execution, Deployment > Compiler

6 - Change Build process heap size (Mbytes) to 1024 and VM Options to -Xmx512m.

Now close the android studio and restart it. The issue will be gone.

Binary numbers in Python

x = x + 1 print(x) a = x + 5 print(a)

Java: JSON -> Protobuf & back conversion

Here is my utility class, you may use:

package <removed>;
import com.google.protobuf.Message;
import com.google.protobuf.MessageOrBuilder;
import com.google.protobuf.util.JsonFormat;
/**
 * Author @espresso stackoverflow.
 * Sample use:
 *      Model.Person reqObj = ProtoUtil.toProto(reqJson, Model.Person.getDefaultInstance());
        Model.Person res = personSvc.update(reqObj);
        final String resJson = ProtoUtil.toJson(res);
 **/
public class ProtoUtil {
    public static <T extends Message> String toJson(T obj){
        try{
            return JsonFormat.printer().print(obj);
        }catch(Exception e){
            throw new RuntimeException("Error converting Proto to json", e);
        }
    }
   public static <T extends MessageOrBuilder> T toProto(String protoJsonStr, T message){
        try{
            Message.Builder builder = message.getDefaultInstanceForType().toBuilder();
            JsonFormat.parser().ignoringUnknownFields().merge(protoJsonStr,builder);
            T out = (T) builder.build();
            return out;
        }catch(Exception e){
            throw new RuntimeException(("Error converting Json to proto", e);
        }
    }
}

Pandas sort by group aggregate and column

Here's a more concise approach...

df['a_bsum'] = df.groupby('A')['B'].transform(sum)
df.sort(['a_bsum','C'], ascending=[True, False]).drop('a_bsum', axis=1)

The first line adds a column to the data frame with the groupwise sum. The second line performs the sort and then removes the extra column.

Result:

    A       B           C
5   baz     -2.301539   True
2   baz     -0.528172   False
1   bar     -0.611756   True
4   bar      0.865408   False
3   foo     -1.072969   True
0   foo      1.624345   False

NOTE: sort is deprecated, use sort_values instead

Twitter Bootstrap scrollable table rows and fixed header

Here is a jQuery plugin that does exactly that: http://fixedheadertable.com/

Usage:

$('selector').fixedHeaderTable({ fixedColumn: 1 });

Set the fixedColumn option if you want any number of columns to be also fixed for horizontal scrolling.

EDIT: This example http://www.datatables.net/examples/basic_init/scroll_y.html is much better in my opinion, although with DataTables you'll need to get a better understanding of how it works in general.

EDIT2: For Bootstrap to work with DataTables you need to follow the instructions here: http://datatables.net/blog/Twitter_Bootstrap_2 (I have tested this and it works)- For Bootstrap 3 there's a discussion here: http://datatables.net/forums/discussion/comment/53462 - (I haven't tested this)

How to fix "could not find a base address that matches schema http"... in WCF

If it is hosted in IIS, there is no need to specify a base address, it will be the address of the virtual directory.

How to make android listview scrollable?

I found a tricky solution... which works only in a RelativeLayout. We only need to put a View above a ListView and set clickable 'true' on View and false for the ListView

 <ListView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/listview
    android:clickable="false" />

<View
    android:layout_width="match_parent"
    android:background="@drawable/gradient_white"
    android:layout_height="match_parent"
    android:clickable="true"
    android:layout_centerHorizontal="true"
    android:layout_alignTop="@+id/listview" />

How to delete all files from a specific folder?

Add the following namespace,

using System.IO;

and use the Directory class to reach on the specific folder:

string[] fileNames = Directory.GetFiles(@"your directory path");
foreach (string fileName in fileNames)
    File.Delete(fileName);

Generic htaccess redirect www to non-www

RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} ^www\.(.*)$ [NC]
RewriteRule ^(.*)$ https://%1/$1 [R=301,L]

Same as Michael's except this one works :P

How do you simulate Mouse Click in C#?

I have combined several sources to produce the code below, which I am currently using. I have also removed the Windows.Forms references so I can use it from console and WPF applications without additional references.

using System;
using System.Runtime.InteropServices;

public class MouseOperations
{
    [Flags]
    public enum MouseEventFlags
    {
        LeftDown = 0x00000002,
        LeftUp = 0x00000004,
        MiddleDown = 0x00000020,
        MiddleUp = 0x00000040,
        Move = 0x00000001,
        Absolute = 0x00008000,
        RightDown = 0x00000008,
        RightUp = 0x00000010
    }

    [DllImport("user32.dll", EntryPoint = "SetCursorPos")]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool SetCursorPos(int x, int y);      

    [DllImport("user32.dll")]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool GetCursorPos(out MousePoint lpMousePoint);

    [DllImport("user32.dll")]
    private static extern void mouse_event(int dwFlags, int dx, int dy, int dwData, int dwExtraInfo);

    public static void SetCursorPosition(int x, int y) 
    {
        SetCursorPos(x, y);
    }

    public static void SetCursorPosition(MousePoint point)
    {
        SetCursorPos(point.X, point.Y);
    }

    public static MousePoint GetCursorPosition()
    {
        MousePoint currentMousePoint;
        var gotPoint = GetCursorPos(out currentMousePoint);
        if (!gotPoint) { currentMousePoint = new MousePoint(0, 0); }
        return currentMousePoint;
    }

    public static void MouseEvent(MouseEventFlags value)
    {
        MousePoint position = GetCursorPosition();

        mouse_event
            ((int)value,
             position.X,
             position.Y,
             0,
             0)
            ;
    }

    [StructLayout(LayoutKind.Sequential)]
    public struct MousePoint
    {
        public int X;
        public int Y;

        public MousePoint(int x, int y)
        {
            X = x;
            Y = y;
        }
    }
}

Serial Port (RS -232) Connection in C++

For the answer above, the default serial port is

        serialParams.BaudRate = 9600;
        serialParams.ByteSize = 8;
        serialParams.StopBits = TWOSTOPBITS;
        serialParams.Parity = NOPARITY;

1064 error in CREATE TABLE ... TYPE=MYISAM

SELECT Email, COUNT(*)
FROM user_log    
WHILE Email IS NOT NULL    
GROUP BY Email    
HAVING COUNT(*) > 1    
ORDER BY UpdateDate DESC 

MySQL said: Documentation #1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'TYPE=MyISAM' at line 36


Which correction below:

CREATE TABLE users_online (
  ip varchar(15) NOT NULL default '',
  time int(11) default NULL,
  PRIMARY KEY  (ip),
  UNIQUE KEY id (ip),
  KEY id_2 (ip)
  TYPE=MyISAM;
)
#                           
# Data untuk tabel `users_online`
#

INSERT INTO users_online VALUES ('127.0.0.1', 1158666872);

Linux error while loading shared libraries: cannot open shared object file: No such file or directory

cd /home/<user_name>/
sudo vi .bash_profile

add these lines at the end

LD_LIBRARY_PATH=/usr/local/lib:<any other paths you want>
export LD_LIBRARY_PATH

document.getElementById("remember").visibility = "hidden"; not working on a checkbox

There are two problems in your code:

  • The property is called visibility and not visiblity.
  • It is not a property of the element itself but of its .style property.

It's easy to fix. Simple replace this:

document.getElementById("remember").visiblity

with this:

document.getElementById("remember").style.visibility

Extend contigency table with proportions (percentages)

Your code doesn't seem so ugly to me...
however, an alternative (not much better) could be e.g. :

df <- data.frame(table(yn))
colnames(df) <- c('Smoker','Freq')
df$Perc <- df$Freq / sum(df$Freq) * 100

------------------
  Smoker Freq Perc
1     No   19 47.5
2    Yes   21 52.5

PHP - If variable is not empty, echo some html code

Your problem is in your use of the_field(), which is for Advanced Custom Fields, a wordpress plugin.

If you want to use a field in a variable you have to use this: $web = get_field('website');.

How do I select text nodes with jQuery?

For me, plain old .contents() appeared to work to return the text nodes, just have to be careful with your selectors so that you know they will be text nodes.

For example, this wrapped all the text content of the TDs in my table with pre tags and had no problems.

jQuery("#resultTable td").content().wrap("<pre/>")

Declaring and initializing a string array in VB.NET

I believe you need to specify "Option Infer On" for this to work.

Option Infer allows the compiler to make a guess at what is being represented by your code, thus it will guess that {"stuff"} is an array of strings. With "Option Infer Off", {"stuff"} won't have any type assigned to it, ever, and so it will always fail, without a type specifier.

Option Infer is, I think On by default in new projects, but Off by default when you migrate from earlier frameworks up to 3.5.

Opinion incoming:

Also, you mention that you've got "Option Explicit Off". Please don't do this.

Setting "Option Explicit Off" means that you don't ever have to declare variables. This means that the following code will silently and invisibly create the variable "Y":

Dim X as Integer
Y = 3

This is horrible, mad, and wrong. It creates variables when you make typos. I keep hoping that they'll remove it from the language.

How to send email from SQL Server?

In-order to make SQL server send email notification you need to create mail profile from Management, database mail.

1) User Right click to get the mail profile menu and choose configure database mail

2)choose the first open (set up a database mail by following the following tasks) and press next Note: if the SMTP is not configured please refer the the URL below

http://www.symantec.com/business/support/index?page=content&id=TECH86263

3) in the second screen fill the the profile name and add SMTP account, then press next

4) choose the type of mail account ( public or private ) then press next

5) change the parameters that related to the sending mail options, and press next 6) press finish

Now to make SQL server send an email if action X happened you can do that via trigger or job ( This is the common ways not the only ones).

1) you can create Job from SQL server agent, then right click on operators and check mails (fill the your email for example) and press OK after that right click Jobs and choose new job and fill the required info as well as the from steps, name, ...etc and from notification tab select the profile you made.

2) from triggers please refer to the example below.

AS
declare @results varchar(max)
declare @subjectText varchar(max)
declare @databaseName VARCHAR(255)
SET @subjectText = 'your subject'
SET @results = 'your results'
-- write the Trigger JOB
EXEC msdb.dbo.sp_send_dbmail
 @profile_name = 'SQLAlerts',
 @recipients = '[email protected]',
 @body = @results,
 @subject = @subjectText,
 @exclude_query_output = 1 --Suppress 'Mail Queued' message
GO

Unable to connect to mongodb Error: couldn't connect to server 127.0.0.1:27017 at src/mongo/shell/mongo.js:L112

I had the same issue until i close teamviewer running on my pc. Then it worked fine!

How do I test a website using XAMPP?

The webpages on an online server reside in a location which looks somewhat like this: http://www.somerandomsite.com/index.php

Since xampp is Offline, it sets up a local server whose address is like this http://localhost/

Basically, xampp sets up a server (apache and others) in your system. And all the files such as index.php, somethingelse.php, etc., reside in the xampp\htdocs\ folder.

The browser locates the server in localhost and will search through the above folder for any resources available in there.

So create any number of folders inside the "xampp\htdocs\" each folder thus forming a website (as you build it).

Sometimes apache won't even start. This is due to the clashing of ports with some applications. Some of them I commonly encounter is Skype. See to that it is killed completely and restart apache

How to replace list item in best way

Or, building on Rusian L.'s suggestion, if the item you're searching for can be in the list more than once::

[Extension()]
public void ReplaceAll<T>(List<T> input, T search, T replace)
{
    int i = 0;
    do {
        i = input.FindIndex(i, s => EqualityComparer<T>.Default.Equals(s, search));

        if (i > -1) {
            FileSystem.input(i) = replace;
            continue;
        }

        break;  
    } while (true);
}

How to read and write into file using JavaScript?

No. Browser-side javascript doesn't have permission to write to the client machine without a lot of security options having to be disabled

Maximize a window programmatically and prevent the user from changing the windows state

When your form is maximized, set its minimum size = max size, so user cannot resize it.

    this.WindowState = FormWindowState.Maximized;
    this.MinimumSize = this.Size;
    this.MaximumSize = this.Size;

What is the difference between Sprint and Iteration in Scrum and length of each Sprint?

Sprint as defined in pure Scrum has the duration 30 calendar days. However Iteration length could be anything as defined by the team.

How to use *ngIf else?

In Angular 4, 5 and 6

We can simply create a template reference variable [2] and link that to the else condition inside an *ngIf directive

The possible Syntaxes [1] are:

<!-- Only If condition -->
<div *ngIf="condition">...</div>
<!-- or -->
<ng-template [ngIf]="condition"><div>...</div></ng-template>


<!-- If and else conditions -->
<div *ngIf="condition; else elseBlock">...</div>
<!-- or -->
<ng-template #elseBlock>...</ng-template>

<!-- If-then-else -->
<div *ngIf="condition; then thenBlock else elseBlock"></div>
<ng-template #thenBlock>...</ng-template>
<ng-template #elseBlock>...</ng-template>


<!-- If and else conditions (storing condition value locally) -->
<div *ngIf="condition as value; else elseBlock">{{value}}</div>
<ng-template #elseBlock>...</ng-template>

DEMO: https://stackblitz.com/edit/angular-feumnt?embed=1&file=src/app/app.component.html

Sources:

  1. https://angular.io/api/common/NgIf#syntax
  2. https://angular.io/guide/template-syntax#template-reference-variables--var-

How does one output bold text in Bash?

This is an old post but regardless, you can also get boldface and italic characters by leveraging utf-32. There are even greek and math symbols that can be used as well as the roman alphabet.

What are the differences between delegates and events?

For people live in 2020, and want a clean answer...

Definitions:

  • delegate: defines a function pointer.
  • event: defines
    • (1) protected interfaces, and
    • (2) operations(+=, -=), and
    • (3) advantage: you don't need to use new keyword anymore.

Regarding the adjective protected:

// eventTest.SomeoneSay = null;              // Compile Error.
// eventTest.SomeoneSay = new Say(SayHello); // Compile Error.

Also notice this section from Microsoft: https://docs.microsoft.com/en-us/dotnet/standard/events/#raising-multiple-events

Code Example:

with delegate:

public class DelegateTest
{
    public delegate void Say(); // Define a pointer type "void <- ()" named "Say".
    private Say say;

    public DelegateTest() {
        say  = new Say(SayHello);     // Setup the field, Say say, first.
        say += new Say(SayGoodBye);
        
        say.Invoke();
    }
    
    public void SayHello() { /* display "Hello World!" to your GUI. */ }
    public void SayGoodBye() { /* display "Good bye!" to your GUI. */ }
}

with event:

public class EventTest
{
    public delegate void Say();
    public event Say SomeoneSay;  // Use the type "Say" to define event, an 
                                  // auto-setup-everything-good field for you.
    public EventTest() {
         SomeoneSay += SayHello;
         SomeoneSay += SayGoodBye;

         SomeoneSay();
    }
    
    public void SayHello() { /* display "Hello World!" to your GUI. */ }
    public void SayGoodBye() { /* display "Good bye!" to your GUI. */ }
}

Reference:

Event vs. Delegate - Explaining the important differences between the Event and Delegate patterns in C# and why they're useful.: https://dzone.com/articles/event-vs-delegate

How to complete the RUNAS command in one line

The runas command does not allow a password on its command line. This is by design (and also the reason you cannot pipe a password to it as input). Raymond Chen says it nicely:

The RunAs program demands that you type the password manually. Why doesn't it accept a password on the command line?

This was a conscious decision. If it were possible to pass the password on the command line, people would start embedding passwords into batch files and logon scripts, which is laughably insecure.

In other words, the feature is missing to remove the temptation to use the feature insecurely.

Executing an EXE file using a PowerShell script

& "C:\Program Files\Automated QA\TestExecute 8\Bin\TestExecute.exe" C:\temp\TestProject1\TestProject1.pjs /run /exit /SilentMode

or

[System.Diagnostics.Process]::Start("C:\Program Files\Automated QA\TestExecute 8\Bin\TestExecute.exe", "C:\temp\TestProject1\TestProject1.pjs /run /exit /SilentMode")

UPDATE: sorry I missed "(I invoked the command using the "&" operator)" sentence. I had this problem when I was evaluating the path dynamically. Try Invoke-Expression construction:

Invoke-Expression "& `"C:\Program Files\Automated QA\TestExecute 8\Bin\TestExecute.exe`" C:\temp\TestProject1\TestProject1.pjs /run /exit /SilentMode"

Can not run Java Applets in Internet Explorer 11 using JRE 7u51

I had the same problem with Java 7 u51. Only after I reset Internet Explorer it work again, Java was enabled in browser etc.

Internet options -> Advanced -> Reset...

How to access the local Django webserver from outside world

For AWS users.

I had to use the following steps to get there.

1) Ensure that pip and django are installed at the sudo level

  • sudo apt-get install python-pip
  • sudo pip install django

2) Ensure that security group in-bound rules includ http on port 80 for 0.0.0.0/0

  • configured through AWS console

3) Add Public IP and DNS to ALLOWED_HOSTS

  • ALLOWED_HOSTS is a list object that you can find in settings.py
  • ALLOWED_HOSTS = ["75.254.65.19","ec2-54-528-27-21.compute-1.amazonaws.com"]

4) Launch development server with sudo on port 80

  • sudo python manage.py runserver 0:80

Site now available at either of the following (no need for :80 as that is default for http):

  • [Public DNS] i.e. ec2-54-528-27-21.compute-1.amazonaws.com
  • [Public IP] i.e 75.254.65.19

What does flex: 1 mean?

flex: 1 means the following:

flex-grow : 1;    ? The div will grow in same proportion as the window-size       
flex-shrink : 1;  ? The div will shrink in same proportion as the window-size 
flex-basis : 0;   ? The div does not have a starting value as such and will 
                     take up screen as per the screen size available for
                     e.g:- if 3 divs are in the wrapper then each div will take 33%.

How to check if spark dataframe is empty?

If you do df.count > 0. It takes the counts of all partitions across all executors and add them up at Driver. This take a while when you are dealing with millions of rows.

The best way to do this is to perform df.take(1) and check if its null. This will return java.util.NoSuchElementException so better to put a try around df.take(1).

The dataframe return an error when take(1) is done instead of an empty row. I have highlighted the specific code lines where it throws the error.

enter image description here

How to remove from a map while iterating it?

Assuming C++11, here is a one-liner loop body, if this is consistent with your programming style:

using Map = std::map<K,V>;
Map map;

// Erase members that satisfy needs_removing(itr)
for (Map::const_iterator itr = map.cbegin() ; itr != map.cend() ; )
  itr = needs_removing(itr) ? map.erase(itr) : std::next(itr);

A couple of other minor style changes:

  • Show declared type (Map::const_iterator) when possible/convenient, over using auto.
  • Use using for template types, to make ancillary types (Map::const_iterator) easier to read/maintain.

Java, Check if integer is multiple of a number

//More Efficiently
public class Multiples {
    public static void main(String[]args) {

        int j = 5;

        System.out.println(j % 4 == 0);

    }
}

C++, copy set to vector

You need to use a back_inserter:

std::copy(input.begin(), input.end(), std::back_inserter(output));

std::copy doesn't add elements to the container into which you are inserting: it can't; it only has an iterator into the container. Because of this, if you pass an output iterator directly to std::copy, you must make sure it points to a range that is at least large enough to hold the input range.

std::back_inserter creates an output iterator that calls push_back on a container for each element, so each element is inserted into the container. Alternatively, you could have created a sufficient number of elements in the std::vector to hold the range being copied:

std::vector<double> output(input.size());
std::copy(input.begin(), input.end(), output.begin());

Or, you could use the std::vector range constructor:

std::vector<double> output(input.begin(), input.end()); 

How do I compare strings in Java?

I agree with the answer from zacherates.

But what you can do is to call intern() on your non-literal strings.

From zacherates example:

// ... but they are not the same object
new String("test") == "test" ==> false 

If you intern the non-literal String equality is true:

new String("test").intern() == "test" ==> true 

iPhone and WireShark

I have successfully captured HTTP traffic using Fiddler2 as a proxy, which can be installed on any Windows PC on your network.

  1. In Fiddler, Tools -> Fiddler Options -> Connections -> [x] Allow remote computers to connect.
  2. Make sure your windows firewall is disabled.
  3. On the iphone/ipod, go to your wireless settings, use a manual proxy server, enter the fiddler machine's ip address and the same port (defaults to 8888).

How can I use Google's Roboto font on a website?

it's easy

every folder of those you downloaded has a different kind of roboto font, means they are different fonts

example: "roboto_regular_macroman"

to use any of them:

1- extract the folder of the font you want to use

2- upload it near the css file

3- now include it in the css file

example for including the font which called "roboto_regular_macroman":

@font-face {
font-family: 'Roboto';
src: url('roboto_regular_macroman/Roboto-Regular-webfont.eot');
src: url('roboto_regular_macroman/Roboto-Regular-webfont.eot?#iefix') format('embedded-opentype'),
     url('roboto_regular_macroman/Roboto-Regular-webfont.woff') format('woff'),
     url('roboto_regular_macroman/Roboto-Regular-webfont.ttf') format('truetype'),
     url('roboto_regular_macroman/Roboto-Regular-webfont.svg#RobotoRegular') format('svg');
font-weight: normal;
font-style: normal;
}

watch for the path of the files, here i uploaded the folder called "roboto_regular_macroman" in the same folder where the css is

then you can now simply use the font by typing font-family: 'Roboto';

How to do a redirect to another route with react-router?

1) react-router > V5 useHistory hook:

If you have React >= 16.8 and functional components you can use the useHistory hook from react-router.

import React from 'react';
import { useHistory } from 'react-router-dom';

const YourComponent = () => {
    const history = useHistory();

    const handleClick = () => {
        history.push("/path/to/push");
    }

    return (
        <div>
            <button onClick={handleClick} type="button" />
        </div>
    );
}

export default YourComponent;

2) react-router > V4 withRouter HOC:

As @ambar mentioned in the comments, React-router has changed their code base since their V4. Here are the documentations - official, withRouter

import React, { Component } from 'react';
import { withRouter } from "react-router-dom";

class YourComponent extends Component {
    handleClick = () => {
        this.props.history.push("path/to/push");
    }

    render() {
        return (
            <div>
                <button onClick={this.handleClick} type="button">
            </div>
        );
    };
}

export default withRouter(YourComponent);

3) React-router < V4 with browserHistory

You can achieve this functionality using react-router BrowserHistory. Code below:

import React, { Component } from 'react';
import { browserHistory } from 'react-router';

export default class YourComponent extends Component {
    handleClick = () => {
        browserHistory.push('/login');
    };

    render() {
        return (
            <div>
                <button onClick={this.handleClick} type="button">
            </div>
        );
    };
}

4) Redux connected-react-router

If you have connected your component with redux, and have configured connected-react-router all you have to do is this.props.history.push("/new/url"); ie, you don't need withRouter HOC to inject history to the component props.

// reducers.js
import { combineReducers } from 'redux';
import { connectRouter } from 'connected-react-router';

export default (history) => combineReducers({
    router: connectRouter(history),
    ... // rest of your reducers
});


// configureStore.js
import { createBrowserHistory } from 'history';
import { applyMiddleware, compose, createStore } from 'redux';
import { routerMiddleware } from 'connected-react-router';
import createRootReducer from './reducers';
...
export const history = createBrowserHistory();

export default function configureStore(preloadedState) {
    const store = createStore(
        createRootReducer(history), // root reducer with router state
        preloadedState,
        compose(
            applyMiddleware(
                routerMiddleware(history), // for dispatching history actions
                // ... other middlewares ...
            ),
        ),
    );

    return store;
}


// set up other redux requirements like for eg. in index.js
import { Provider } from 'react-redux';
import { Route, Switch } from 'react-router';
import { ConnectedRouter } from 'connected-react-router';
import configureStore, { history } from './configureStore';
...
const store = configureStore(/* provide initial state if any */)

ReactDOM.render(
    <Provider store={store}>
        <ConnectedRouter history={history}>
            <> { /* your usual react-router v4/v5 routing */ }
                <Switch>
                    <Route exact path="/yourPath" component={YourComponent} />
                </Switch>
            </>
        </ConnectedRouter>
    </Provider>,
    document.getElementById('root')
);


// YourComponent.js
import React, { Component } from 'react';
import { connect } from 'react-redux';
...

class YourComponent extends Component {
    handleClick = () => {
        this.props.history.push("path/to/push");
    }

    render() {
        return (
          <div>
            <button onClick={this.handleClick} type="button">
          </div>
        );
      }
    };

}

export default connect(mapStateToProps = {}, mapDispatchToProps = {})(YourComponent);

Programmatically select a row in JTable

You can do it calling setRowSelectionInterval :

table.setRowSelectionInterval(0, 0);

to select the first row.

Spring MVC - How to get all request params in a map in Spring controller?

Use org.springframework.web.context.request.WebRequest as a parameter in your controller method, it provides the method getParameterMap(), the advantage is that you do not tight your application to the Servlet API, the WebRequest is a example of JavaEE pattern Context Object.

finished with non zero exit value

BuildToolsVersion & Dependencies must be same with Base API version.

buildToolsVersion '23.0.2' & compile 

&

com.android.support:appcompat-v7:24.0.0-alpha1

can not match with base API level.

It should be

compile 'com.android.support:appcompat-v7:21.0.3'

Done

Android 'Unable to add window -- token null is not for an application' exception

You can continue to use getApplicationContext(), but before use, you should add this flag: dialog.getWindow().setType(WindowManager.LayoutParams.TYPE_SYSTEM_ALERT), and the error will not show.

And don't forget to add permission:

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

SQLAlchemy insert or update example

I try lots of ways and finally try this:

def db_persist(func):
    def persist(*args, **kwargs):
        func(*args, **kwargs)
        try:
            session.commit()
            logger.info("success calling db func: " + func.__name__)
            return True
        except SQLAlchemyError as e:
            logger.error(e.args)
            session.rollback()
            return False

    return persist

and :

@db_persist
def insert_or_update(table_object):
    return session.merge(table_object)

Finishing current activity from a fragment

Very simple...

1- just grab activity by getActivity() in the fragment

2- then call finish();

So just getActivity().finish(); will finish the parent activity.

Execute action when back bar button of UINavigationController is pressed

If you are using navigationController then add the UINavigationControllerDelegate protocol to class and add the delegate method as follows:

class ViewController:UINavigationControllerDelegate {

    func navigationController(navigationController: UINavigationController, willShowViewController viewController: UIViewController,
animated: Bool) {
        if viewController === self {
            // do here what you want
        }
    }
}

This method is called whenever the navigation controller will slide to a new screen. If the back button was pressed, the new view controller is ViewController itself.

how to increase sqlplus column output length?

Actually, even that didn't work for me. When I executed "select dbms_metadata.get_ddl('TABLESPACE','TABLESPACE_NAME') from dual;" I again got only the first three lines, but this time each line was padded out to 15,000 characters. I was able to work around this with:

select substr(dbms_metadata.get_ddl('TABLESPACE','LM_THIN_DATA'),80) from dual;
select substr(dbms_metadata.get_ddl('TABLESPACE','LM_THIN_DATA'),160) from dual;
select substr(dbms_metadata.get_ddl('TABLESPACE','LM_THIN_DATA'),240) from dual;

It sure seemed like there ought to be an easier way, but I couldn't seem to find it.

Checking the form field values before submitting that page

You can simply make the start_date required using

<input type="submit" value="Submit" required />

You don't even need the checkform() then.

Thanks

how to use a like with a join in sql?

In MySQL you could try:

SELECT * FROM A INNER JOIN B ON B.MYCOL LIKE CONCAT('%', A.MYCOL, '%');

Of course this would be a massively inefficient query because it would do a full table scan.

Update: Here's a proof


create table A (MYCOL varchar(255));
create table B (MYCOL varchar(255));
insert into A (MYCOL) values ('foo'), ('bar'), ('baz');
insert into B (MYCOL) values ('fooblah'), ('somethingfooblah'), ('foo');
insert into B (MYCOL) values ('barblah'), ('somethingbarblah'), ('bar');
SELECT * FROM A INNER JOIN B ON B.MYCOL LIKE CONCAT('%', A.MYCOL, '%');
+-------+------------------+
| MYCOL | MYCOL            |
+-------+------------------+
| foo   | fooblah          |
| foo   | somethingfooblah |
| foo   | foo              |
| bar   | barblah          |
| bar   | somethingbarblah |
| bar   | bar              |
+-------+------------------+
6 rows in set (0.38 sec)

What is a Memory Heap?

It's a chunk of memory allocated from the operating system by the memory manager in use by a process. Calls to malloc() et alia then take memory from this heap instead of having to deal with the operating system directly.

Find unique lines

uniq should do fine if you're file is/can be sorted, if you can't sort the file for some reason you can use awk:

awk '{a[$0]++}END{for(i in a)if(a[i]<2)print i}'

How to rename a file using svn?

Using TortoiseSVN worked easily on Windows for me.

http://tortoisesvn.net/

Right click file -> TortoiseSVN menu -> Repo-browser -> right click file in repository -> rename -> press Enter -> click Ok

Using SVN 1.8.8 TortoiseSVN version 1.8.5

Limit on the WHERE col IN (...) condition

For MS SQL 2016, passing ints into the in, it looks like it can handle close to 38,000 records.

select * from user where userId in (1,2,3,etc)

jQuery Selector: Id Ends With?

If you know the element type then: (eg: replace 'element' with 'div')

$("element[id$='txtTitle']")

If you don't know the element type:

$("[id$='txtTitle']")

More information available


_x000D_
_x000D_
// the old way, needs exact ID: document.getElementById("hi").value = "kk";_x000D_
$(function() {_x000D_
  $("[id$='txtTitle']").val("zz");_x000D_
});
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<input id="ctl_blabla_txtTitle" type="text" />
_x000D_
_x000D_
_x000D_

JQuery datepicker not working

Datepicker is not part of jQuery. You have to get jQuery UI to use the datepicker.

Index of element in NumPy array

You can convert a numpy array to list and get its index .

for example:

tmp = [1,2,3,4,5] #python list
a = numpy.array(tmp) #numpy array
i = list(a).index(2) # i will return index of 2, which is 1

this is just what you wanted.

Check whether an array is empty

I can't replicate that (php 5.3.6):

php > $error = array();
php > $error['something'] = false;
php > $error['somethingelse'] = false;
php > var_dump(empty($error));
bool(false)

php > $error = array();
php > var_dump(empty($error));
bool(true)
php >

exactly where are you doing the empty() call that returns true?

Replace Default Null Values Returned From Left Outer Join

MySQL

COALESCE(field, 'default')

For example:

  SELECT
    t.id,
    COALESCE(d.field, 'default')
  FROM
     test t
  LEFT JOIN
     detail d ON t.id = d.item

Also, you can use multiple columns to check their NULL by COALESCE function. For example:

mysql> SELECT COALESCE(NULL, 1, NULL);
        -> 1
mysql> SELECT COALESCE(0, 1, NULL);
        -> 0
mysql> SELECT COALESCE(NULL, NULL, NULL);
        -> NULL

Get list of all input objects using JavaScript, without accessing a form object

(See update at end of answer.)

You can get a NodeList of all of the input elements via getElementsByTagName (DOM specification, MDC, MSDN), then simply loop through it:

var inputs, index;

inputs = document.getElementsByTagName('input');
for (index = 0; index < inputs.length; ++index) {
    // deal with inputs[index] element.
}

There I've used it on the document, which will search the entire document. It also exists on individual elements (DOM specification), allowing you to search only their descendants rather than the whole document, e.g.:

var container, inputs, index;

// Get the container element
container = document.getElementById('container');

// Find its child `input` elements
inputs = container.getElementsByTagName('input');
for (index = 0; index < inputs.length; ++index) {
    // deal with inputs[index] element.
}

...but you've said you don't want to use the parent form, so the first example is more applicable to your question (the second is just there for completeness, in case someone else finding this answer needs to know).


Update: getElementsByTagName is an absolutely fine way to do the above, but what if you want to do something slightly more complicated, like just finding all of the checkboxes instead of all of the input elements?

That's where the useful querySelectorAll comes in: It lets us get a list of elements that match any CSS selector we want. So for our checkboxes example:

var checkboxes = document.querySelectorAll("input[type=checkbox]");

You can also use it at the element level. For instance, if we have a div element in our element variable, we can find all of the spans with the class foo that are inside that div like this:

var fooSpans = element.querySelectorAll("span.foo");

querySelectorAll and its cousin querySelector (which just finds the first matching element instead of giving you a list) are supported by all modern browsers, and also IE8.

True/False vs 0/1 in MySQL

In MySQL TRUE and FALSE are synonyms for TINYINT(1).

So therefore its basically the same thing, but MySQL is converting to 0/1 - so just use a TINYINT if that's easier for you

P.S.
The performance is likely to be so minuscule (if at all), that if you need to ask on StackOverflow, then it won't affect your database :)

Create SQLite Database and table

The next link will bring you to a great tutorial, that helped me a lot!

How to SQLITE in C#

I nearly used everything in that article to create the SQLite database for my own C# Application.

Don't forget to download the SQLite.dll, and add it as a reference to your project. This can be done using NuGet and by adding the dll manually.

After you added the reference, refer to the dll from your code using the following line on top of your class:

using System.Data.SQLite;

You can find the dll's here:

SQLite DLL's

You can find the NuGet way here:

NuGet

Up next is the create script. Creating a database file:

SQLiteConnection.CreateFile("MyDatabase.sqlite");

SQLiteConnection m_dbConnection = new SQLiteConnection("Data Source=MyDatabase.sqlite;Version=3;");
m_dbConnection.Open();

string sql = "create table highscores (name varchar(20), score int)";

SQLiteCommand command = new SQLiteCommand(sql, m_dbConnection);
command.ExecuteNonQuery();

sql = "insert into highscores (name, score) values ('Me', 9001)";

command = new SQLiteCommand(sql, m_dbConnection);
command.ExecuteNonQuery();

m_dbConnection.Close();

After you created a create script in C#, I think you might want to add rollback transactions, it is safer and it will keep your database from failing, because the data will be committed at the end in one big piece as an atomic operation to the database and not in little pieces, where it could fail at 5th of 10 queries for example.

Example on how to use transactions:

 using (TransactionScope tran = new TransactionScope())
 {
     //Insert create script here.

     //Indicates that creating the SQLiteDatabase went succesfully, so the database can be committed.
     tran.Complete();
 }

Can you 'exit' a loop in PHP?

break; leaves your loop.

continue; skips any code for the remainder of that loop and goes on to the next loop, so long as the condition is still true.

'list' object has no attribute 'shape'

import numpy
X = numpy.array(the_big_nested_list_you_had)

It's still not going to do what you want; you have more bugs, like trying to unpack a 3-dimensional shape into two target variables in test.

HTML select dropdown list

Have <option value="">- Please select a name -</option> as the first option and use JavaScript (and backend validation) to ensure the user has selected something other than an empty value.

How to crop an image using PIL?

You need to import PIL (Pillow) for this. Suppose you have an image of size 1200, 1600. We will crop image from 400, 400 to 800, 800

from PIL import Image
img = Image.open("ImageName.jpg")
area = (400, 400, 800, 800)
cropped_img = img.crop(area)
cropped_img.show()

java.lang.ClassNotFoundException: org.apache.jsp.index_jsp

I had to delete Tomcat's work directory as it had cached previously generated files. To do this:

  1. Stop Tomcat
  2. Delete the 'work' directory
  3. Start Tomcat

This will cause the work directory to be newly generated.

C++ IDE for Linux?

And then I noticed that this simply isn't how you work there*, and I threw everything out, spent a few days reading manuals, set up my shell (bash), set up a GVIM environment, learned the GCC/binutils toolchain, make and gdb and lived happily ever after.

I'd mostly agree, but the problem is also one of perception: we forget how difficult it was to become productive in any chose IDE (or other environment). I find IDE's (Visual Studio, NetBeans, Eclipse) amazingly cumbersome in so many ways.

As an old-time UNIX guy, I always use Emacs. But that has a pretty steep and long learning curve, so I'm not sure I can recommend it to newcomers.

I'd second that; use Emacs as my primary editor on both Linux and on MSW (XP2,W2K). I would disagree that it has a steep learning curve, but would say that because of the huge number of features it has a long learning curve. You can be productive within a short time, but if you want you can learn new features of it for years to come.

However -- don't expect all the features of Emacs to be available on drop-down menus, there is just too much functionality to find it there.

As I metioned, I've used GNU Emacs on MSW for years. And it's always worked well with Visual Studio until I "upgraded" to 2008; now it sometimes delays many seconds before refreshing files from disk. The main reason for editing in the VS window is the "Intellisense" code completion feature.

Automatically resize jQuery UI dialog to the width of the content loaded by ajax

Had the same problem and thanks to you mentioning that the real problem was related to CSS I found the issue:

Having position:relative instead of position:absolute in your .ui-dialog CSS rule makes the dialog and width:'auto' behave strangely.

.ui-dialog { position: absolute;}

differences between using wmode="transparent", "opaque", or "window" for an embedded object on a webpage

Opaque will cause less system strain since 'transparent' will still attempt to apply alpha. The reason you see transparent used instead is because most web authors don't pay attention to detail (ie, just copy-pasted some embed code they found).

BTW, you are correct about it being undocumented. The best I've ever seen is a blog by a guy who claims to have talked to a Macromedia developer about it. Unfortunaetly I can't find the link.

EDIT: I think it was this one: http://www.communitymx.com/content/article.cfm?cid=e5141

Execute method on startup in Spring

Attention, this is only advised if your runOnceOnStartup method depends on a fully initialized spring context. For example: you wan to call a dao with transaction demarcation

You can also use a scheduled method with fixedDelay set very high

@Scheduled(fixedDelay = Long.MAX_VALUE)
public void runOnceOnStartup() {
    dosomething();
}

This has the advantage that the whole application is wired up (Transactions, Dao, ...)

seen in Scheduling tasks to run once, using the Spring task namespace

Error 330 (net::ERR_CONTENT_DECODING_FAILED):

One more idea for anyone else getting this...

I had some gzipped svg, but it had a php error in the output, which caused this error message. (Because there was text in the middle of gzip binary.) Fixing the php error solved it.

MySQL table is marked as crashed and last (automatic?) repair failed

I tried the options in the existing answers, mainly the one marked correct which did not work in my scenario. However, what did work was using phpMyAdmin. Select the database and then select the table, from the bottom drop down menu select "Repair table".

  • Server type: MySQL
  • Server version: 5.7.23 - MySQL Community Server (GPL)
  • phpMyAdmin: Version information: 4.7.7

The specified type member 'Date' is not supported in LINQ to Entities. Only initializers, entity members, and entity navigation properties

Simplified:

DateTime time = System.DateTime.Now;
ModelName m = context.TableName.Where(x=> DbFunctions.TruncateTime(x.Date) == time.Date)).FirstOrDefault();

Text was truncated or one or more characters had no match in the target code page including the primary key in an unpivot

Not really a technical solution, but SQL Server 2017 flat file import is totally revamped, and imported my large-ish file with 5 clicks, handled encoding / field length issues without any input from me

enter image description here

How do I protect Python code?

The reliable only way to protect code is to run it on a server you control and provide your clients with a client which interfaces with that server.

PHP string "contains"

You can use these string functions,

strstr — Find the first occurrence of a string

stristr — Case-insensitive strstr()

strrchr — Find the last occurrence of a character in a string

strpos — Find the position of the first occurrence of a substring in a string

strpbrk — Search a string for any of a set of characters

If that doesn't help then you should use preg regular expression

preg_match — Perform a regular expression match

How do I add a resources folder to my Java project in Eclipse

Try To Give Full path for reading image.

Example image = ImageIO.read(new File("D:/work1/Jan14Stackoverflow/src/Strawberry.jpg"));

your code is not producing any exception after giving the full path. If you want to just read an image file in java code. Refer the following - http://docs.oracle.com/javase/tutorial/2d/images/examples/LoadImageApp.java

If the object of your class is created at end your code works fine for me and displays the image

// PracticeFrame pframe = new PracticeFrame();//comment this

new PracticeFrame().add(panel);

php - insert a variable in an echo string

echo '<p class="paragrah"' . $i . '">'

regex string replace

Your character class (the part in the square brackets) is saying that you want to match anything except 0-9 and a-z and +. You aren't explicit about how many a-z or 0-9 you want to match, but I assume the + means you want to replace strings of at least one alphanumeric character. It should read instead:

str = str.replace(/[^-a-z0-9]+/g, "");

Also, if you need to match upper-case letters along with lower case, you should use:

str = str.replace(/[^-a-zA-Z0-9]+/g, "");

How to do a case sensitive search in WHERE clause (I'm using SQL Server)?

You can make the query using convert to varbinary – it’s very easy. Example:

Select * from your_table where convert(varbinary, your_column) = convert(varbinary, 'aBcD') 

MySQL Alter Table Add Field Before or After a field already present

$query = "ALTER TABLE `" . $table_prefix . "posts_to_bookmark` 
          ADD COLUMN `ping_status` INT(1) NOT NULL 
          AFTER `<TABLE COLUMN BEFORE THIS COLUMN>`";

I believe you need to have ADD COLUMN and use AFTER, not BEFORE.

In case you want to place column at the beginning of a table, use the FIRST statement:

$query = "ALTER TABLE `" . $table_prefix . "posts_to_bookmark`
          ADD COLUMN `ping_status` INT(1) NOT NULL 
          FIRST";

http://dev.mysql.com/doc/refman/5.1/en/alter-table.html

How to create a notification with NotificationCompat.Builder?

The NotificationCompat.Builder is the most easy way to create Notifications on all Android versions. You can even use features that are available with Android 4.1. If your app runs on devices with Android >=4.1 the new features will be used, if run on Android <4.1 the notification will be an simple old notification.

To create a simple Notification just do (see Android API Guide on Notifications):

NotificationCompat.Builder mBuilder =
    new NotificationCompat.Builder(this)
    .setSmallIcon(R.drawable.notification_icon)
    .setContentTitle("My notification")
    .setContentText("Hello World!")
    .setContentIntent(pendingIntent); //Required on Gingerbread and below

You have to set at least smallIcon, contentTitle and contentText. If you miss one the Notification will not show.

Beware: On Gingerbread and below you have to set the content intent, otherwise a IllegalArgumentException will be thrown.

To create an intent that does nothing, use:

final Intent emptyIntent = new Intent();
PendingIntent pendingIntent = PendingIntent.getActivity(ctx, NOT_USED, emptyIntent, PendingIntent.FLAG_UPDATE_CURRENT);

You can add sound through the builder, i.e. a sound from the RingtoneManager:

mBuilder.setSound(RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION))

The Notification is added to the bar through the NotificationManager:

NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
notificationManager.notify(mId, mBuilder.build());

Enable 'xp_cmdshell' SQL Server

You can also hide again advanced option after reconfigure:

-- show advanced options
EXEC sp_configure 'show advanced options', 1
GO
RECONFIGURE
GO
-- enable xp_cmdshell
EXEC sp_configure 'xp_cmdshell', 1
GO
RECONFIGURE
GO
-- hide advanced options
EXEC sp_configure 'show advanced options', 0
GO
RECONFIGURE
GO

The specified DSN contains an architecture mismatch between the Driver and Application. JAVA

If you are using netbeans go to tools-> java Platform, change jdk_home which points to c:/programfiles/java/jdk1_7 to c:programFiles(x86)/java/jdk1_6_21

if not editable find netbeans.cnf and make change as stated abouve for jdk_home. restart neatbeans and how it works I had the same problem , but i worked .

How to Kill A Session or Session ID (ASP.NET/C#)

Session.Abandon(); did not work for me either.

The way I had to write it to get it to work was like this. Might work for you too.

HttpContext.Current.Session.Abandon();

Getting indices of True values in a boolean list

Simply do this:

def which_index(self):
    return [
        i for i in range(len(self.states))
        if self.states[i] == True
    ]

Create a data.frame with m columns and 2 rows

For completeness:

Along the lines of Chase's answer, I usually use as.data.frame to coerce the matrix to a data.frame:

m <- as.data.frame(matrix(0, ncol = 30, nrow = 2))

EDIT: speed test data.frame vs. as.data.frame

system.time(replicate(10000, data.frame(matrix(0, ncol = 30, nrow = 2))))
   user  system elapsed 
  8.005   0.108   8.165 

system.time(replicate(10000, as.data.frame(matrix(0, ncol = 30, nrow = 2))))
   user  system elapsed 
  3.759   0.048   3.802 

Yes, it appears to be faster (by about 2 times).

Resetting MySQL Root Password with XAMPP on Localhost

Follow the following steps:

  1. Open the XAMPP control panel and click on the shell and open the shell.
  2. In the shell run the following : mysql -h localhost -u root -p and press enter. It will as for a password, by default the password is blank so just press enter
  3. Then just run the following query SET PASSWORD FOR 'root'@'localhost' = PASSWORD('newpassword'); and press enter and your password is updated for root user on localhost

MySQL timestamp select date range

This SQL query will extract the data for you. It is easy and fast.

SELECT *
  FROM table_name
  WHERE extract( YEAR_MONTH from timestamp)="201010";

What is the syntax for an inner join in LINQ to SQL?

try instead this,

var dealer = from d in Dealer
             join dc in DealerContact on d.DealerID equals dc.DealerID
             select d;

Asp.net Validation of viewstate MAC failed

I had this problem, and for me the answer was different than the other answers to this question.

I have an application with a lot of customers. I catch all error in the application_error in global.asax and I send myself an email with the error detail. After I published a new version of my apps, I began receiving a lot of Validation of viewstate MAC failed error message.

After a day of searching I realized that I have a timer in my apps, that refresh an update panel every minute. So when I published a new version of my apps, and some customer have left her computer open on my website. I receive an error message every time that the timer refresh because the actual viewstate does not match with the new one. I received this message until all customers closed the website or refresh their browser to get the new version.

I'm sorry for my English, and I know that my case is very specific, but if it can help someone to save a day, I think that it is a good thing.

Change placeholder text

Try accessing the placeholder attribute of the input and change its value like the following:

$('#some_input_id').attr('placeholder','New Text Here');

Can also clear the placeholder if required like:

$('#some_input_id').attr('placeholder','');

Sending POST parameters with Postman doesn't work, but sending GET parameters does

I was having the same problem. To fix it I added the following headers:

Content-Type: application/json

I had to manually add the content type even though I also had the type of "json" in the raw post field parameters.

How to remove certain characters from a string in C++?

   string str("(555) 555-5555");

   char chars[] = "()-";

   for (unsigned int i = 0; i < strlen(chars); ++i)
   {
      // you need include <algorithm> to use general algorithms like std::remove()
      str.erase (std::remove(str.begin(), str.end(), chars[i]), str.end());
   }

   // output: 555 5555555
   cout << str << endl;

To use as function:

void removeCharsFromString( string &str, char* charsToRemove ) {
   for ( unsigned int i = 0; i < strlen(charsToRemove); ++i ) {
      str.erase( remove(str.begin(), str.end(), charsToRemove[i]), str.end() );
   }
}
//example of usage:
removeCharsFromString( str, "()-" );

How to succinctly write a formula with many variables from a data frame?

I build this solution, reformulate does not take care if variable names have white spaces.

add_backticks = function(x) {
    paste0("`", x, "`")
}

x_lm_formula = function(x) {
    paste(add_backticks(x), collapse = " + ")
}

build_lm_formula = function(x, y){
    if (length(y)>1){
        stop("y needs to be just one variable")
    }
    as.formula(        
        paste0("`",y,"`", " ~ ", x_lm_formula(x))
    )
}

# Example
df <- data.frame(
    y = c(1,4,6), 
    x1 = c(4,-1,3), 
    x2 = c(3,9,8), 
    x3 = c(4,-4,-2)
    )

# Model Specification
columns = colnames(df)
y_cols = columns[1]
x_cols = columns[2:length(columns)]
formula = build_lm_formula(x_cols, y_cols)
formula
# output
# "`y` ~ `x1` + `x2` + `x3`"

# Run Model
lm(formula = formula, data = df)
# output
Call:
    lm(formula = formula, data = df)

Coefficients:
    (Intercept)           x1           x2           x3  
        -5.6316       0.7895       1.1579           NA  

```

How can I check if char* variable points to empty string?

My preferred method:

if (*ptr == 0) // empty string

Probably more common:

if (strlen(ptr) == 0) // empty string

Changing the tmp folder of mysql

Here is an example to move the mysqld tmpdir from /tmp to /run/mysqld which already exists on Ubuntu 13.04 and is a tmpfs (memory/ram):

sudo vim /etc/mysql/conf.d/local.cnf

Add:

[mysqld]
tmpdir = /run/mysqld

Then:

sudo service mysql restart

Verify:

SHOW VARIABLES LIKE 'tmpdir';

==================================================================

If you get an error on MySQL restart, you may have AppArmor enabled:

sudo vim /etc/apparmor.d/local/usr.sbin.mysqld

Add:

# Site-specific additions and overrides for usr.sbin.mysqld.
# For more details, please see /etc/apparmor.d/local/README.
/run/mysqld/ r,
/run/mysqld/** rwk,

Then:

sudo service apparmor reload 

sources: http://2bits.com/articles/reduce-your-servers-resource-usage-moving-mysql-temporary-directory-ram-disk.html, https://blogs.oracle.com/jsmyth/entry/apparmor_and_mysql

JQuery Validate Dropdown list

I have modified your code a little. Here's a working version (for me):

    <select name="dd1" id="dd1">
       <option value="none">None</option>
       <option value="o1">option 1</option>
       <option value="o2">option 2</option>
       <option value="o3">option 3</option>
    </select>  
    <div style="color:red;" id="msg_id"></div>

<script>
    $('#everything').submit(function(e){ 
        var department = $("#msg_id");
        var msg = "Please select Department";
            if ($('#dd1').val() == "") {
                department.append(msg);
                e.preventDefault();
                return false;
            }
        });
 </script>

Delete files older than 10 days using shell script in Unix

If you can afford working via the file data, you can do

find -mmin +14400 -delete

How to initialize all the elements of an array to any specific value in java

Evidently you can use Arrays.fill(), The way you have it done also works though.

How to remove an element from the flow?

I know this question is several years old, but what I think you're trying to do is get it so where a large element, like an image doesn't interfere with the height of a div?

I just ran into something similar, where I wanted an image to overflow a div, but I wanted it to be at the end of a string of text, so I didn't know where it would end up being.

A solution I figured out was to put the margin-bottom: -element's height, so if the image is 20px hight,

margin-bottom: -20px; vertical-align: top;

for example.

That way it floated over the outside of the div, and stayed next to the last word in the string.

How to write some data to excel file(.xlsx)

Try this code

Microsoft.Office.Interop.Excel.Application oXL;
Microsoft.Office.Interop.Excel._Workbook oWB;
Microsoft.Office.Interop.Excel._Worksheet oSheet;
Microsoft.Office.Interop.Excel.Range oRng;
object misvalue = System.Reflection.Missing.Value;
try
{
    //Start Excel and get Application object.
    oXL = new Microsoft.Office.Interop.Excel.Application();
    oXL.Visible = true;

    //Get a new workbook.
    oWB = (Microsoft.Office.Interop.Excel._Workbook)(oXL.Workbooks.Add(""));
    oSheet = (Microsoft.Office.Interop.Excel._Worksheet)oWB.ActiveSheet;

    //Add table headers going cell by cell.
    oSheet.Cells[1, 1] = "First Name";
    oSheet.Cells[1, 2] = "Last Name";
    oSheet.Cells[1, 3] = "Full Name";
    oSheet.Cells[1, 4] = "Salary";

    //Format A1:D1 as bold, vertical alignment = center.
    oSheet.get_Range("A1", "D1").Font.Bold = true;
    oSheet.get_Range("A1", "D1").VerticalAlignment =
        Microsoft.Office.Interop.Excel.XlVAlign.xlVAlignCenter;

    // Create an array to multiple values at once.
    string[,] saNames = new string[5, 2];

    saNames[0, 0] = "John";
    saNames[0, 1] = "Smith";
    saNames[1, 0] = "Tom";

    saNames[4, 1] = "Johnson";

    //Fill A2:B6 with an array of values (First and Last Names).
    oSheet.get_Range("A2", "B6").Value2 = saNames;

    //Fill C2:C6 with a relative formula (=A2 & " " & B2).
    oRng = oSheet.get_Range("C2", "C6");
    oRng.Formula = "=A2 & \" \" & B2";

    //Fill D2:D6 with a formula(=RAND()*100000) and apply format.
    oRng = oSheet.get_Range("D2", "D6");
    oRng.Formula = "=RAND()*100000";
    oRng.NumberFormat = "$0.00";

    //AutoFit columns A:D.
    oRng = oSheet.get_Range("A1", "D1");
    oRng.EntireColumn.AutoFit();

    oXL.Visible = false;
    oXL.UserControl = false;
    oWB.SaveAs("c:\\test\\test505.xls", Microsoft.Office.Interop.Excel.XlFileFormat.xlWorkbookDefault, Type.Missing, Type.Missing,
        false, false, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlNoChange,
        Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);

    oWB.Close();
    oXL.Quit();

    //...

Remove ALL styling/formatting from hyperlinks

if you state a.redLink{color:red;} then to keep this on hover and such add a.redLink:hover{color:red;} This will make sure no other hover states will change the color of your links

Why do some functions have underscores "__" before and after the function name?

This convention is used for special variables or methods (so-called “magic method”) such as __init__ and __len__. These methods provides special syntactic features or do special things.

For example, __file__ indicates the location of Python file, __eq__ is executed when a == b expression is executed.

A user of course can make a custom special method, which is a very rare case, but often might modify some of the built-in special methods (e.g. you should initialize the class with __init__ that will be executed at first when an instance of a class is created).

class A:
    def __init__(self, a):  # use special method '__init__' for initializing
        self.a = a
    def __custom__(self):  # custom special method. you might almost do not use it
        pass

How to clear basic authentication details in chrome

You should be able to clear your credentials from your browser via "Clear Browsing Data..." in chrome://settings/advanced

Keep only first n characters in a string?

Use the string.substring(from, to) API. In your case, use string.substring(0,8).

onchange event for html.dropdownlist

If you don't want jquery then you can do it with javascript :-

@Html.DropDownList("Sortby", new SelectListItem[] 
{ 
     new SelectListItem() { Text = "Newest to Oldest", Value = "0" }, 
     new SelectListItem() { Text = "Oldest to Newest", Value = "1" }},
     new { @onchange="callChangefunc(this.value)" 
});

<script>
    function callChangefunc(val){
        window.location.href = "/Controller/ActionMethod?value=" + val;
    }
</script>

How do I programmatically get the GUID of an application in .NET 2.0

To get the appID you could use the following line of code:

var applicationId = ((GuidAttribute)typeof(Program).Assembly.GetCustomAttributes(typeof(GuidAttribute), true)[0]).Value;

For this you need to include the System.Runtime.InteropServices;

What does "Fatal error: Unexpectedly found nil while unwrapping an Optional value" mean?

This answer is community wiki. If you feel it could be made better, feel free to edit it!

Background: What’s an Optional?

In Swift, Optional<Wrapped> is an option type: it can contain any value from the original ("Wrapped") type, or no value at all (the special value nil). An optional value must be unwrapped before it can be used.

Optional is a generic type, which means that Optional<Int> and Optional<String> are distinct types — the type inside <> is called the Wrapped type. Under the hood, an Optional is an enum with two cases: .some(Wrapped) and .none, where .none is equivalent to nil.

Optionals can be declared using the named type Optional<T>, or (most commonly) as a shorthand with a ? suffix.

var anInt: Int = 42
var anOptionalInt: Int? = 42
var anotherOptionalInt: Int?  // `nil` is the default when no value is provided
var aVerboseOptionalInt: Optional<Int>  // equivalent to `Int?`

anOptionalInt = nil // now this variable contains nil instead of an integer

Optionals are a simple yet powerful tool to express your assumptions while writing code. The compiler can use this information to prevent you from making mistakes. From The Swift Programming Language:

Swift is a type-safe language, which means the language helps you to be clear about the types of values your code can work with. If part of your code requires a String, type safety prevents you from passing it an Int by mistake. Likewise, type safety prevents you from accidentally passing an optional String to a piece of code that requires a non-optional String. Type safety helps you catch and fix errors as early as possible in the development process.

Some other programming languages also have generic option types: for example, Maybe in Haskell, option in Rust, and optional in C++17.

In programming languages without option types, a particular "sentinel" value is often used to indicate the absence of a valid value. In Objective-C, for example, nil (the null pointer) represents the lack of an object. For primitive types such as int, a null pointer can't be used, so you would need either a separate variable (such as value: Int and isValid: Bool) or a designated sentinel value (such as -1 or INT_MIN). These approaches are error-prone because it's easy to forget to check isValid or to check for the sentinel value. Also, if a particular value is chosen as the sentinel, that means it can no longer be treated as a valid value.

Option types such as Swift's Optional solve these problems by introducing a special, separate nil value (so you don't have to designate a sentinel value), and by leveraging the strong type system so the compiler can help you remember to check for nil when necessary.


Why did I get “fatal error: unexpectedly found nil while unwrapping an Optional value”?

In order to access an optional’s value (if it has one at all), you need to unwrap it. An optional value can be unwrapped safely or forcibly. If you force-unwrap an optional, and it didn't have a value, your program will crash with the above message.

Xcode will show you the crash by highlighting a line of code. The problem occurs on this line.

crashed line

This crash can occur with two different kinds of force-unwrap:

1. Explicit Force Unwrapping

This is done with the ! operator on an optional. For example:

let anOptionalString: String?
print(anOptionalString!) // <- CRASH

Fatal error: Unexpectedly found nil while unwrapping an Optional value

As anOptionalString is nil here, you will get a crash on the line where you force unwrap it.

2. Implicitly Unwrapped Optionals

These are defined with a !, rather than a ? after the type.

var optionalDouble: Double!   // this value is implicitly unwrapped wherever it's used

These optionals are assumed to contain a value. Therefore whenever you access an implicitly unwrapped optional, it will automatically be force unwrapped for you. If it doesn’t contain a value, it will crash.

print(optionalDouble) // <- CRASH

Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value

In order to work out which variable caused the crash, you can hold ? while clicking to show the definition, where you might find the optional type.

IBOutlets, in particular, are usually implicitly unwrapped optionals. This is because your xib or storyboard will link up the outlets at runtime, after initialization. You should therefore ensure that you’re not accessing outlets before they're loaded in. You also should check that the connections are correct in your storyboard/xib file, otherwise the values will be nil at runtime, and therefore crash when they are implicitly unwrapped. When fixing connections, try deleting the lines of code that define your outlets, then reconnect them.


When should I ever force unwrap an Optional?

Explicit Force Unwrapping

As a general rule, you should never explicitly force unwrap an optional with the ! operator. There may be cases where using ! is acceptable – but you should only ever be using it if you are 100% sure that the optional contains a value.

While there may be an occasion where you can use force unwrapping, as you know for a fact that an optional contains a value – there is not a single place where you cannot safely unwrap that optional instead.

Implicitly Unwrapped Optionals

These variables are designed so that you can defer their assignment until later in your code. It is your responsibility to ensure they have a value before you access them. However, because they involve force unwrapping, they are still inherently unsafe – as they assume your value is non-nil, even though assigning nil is valid.

You should only be using implicitly unwrapped optionals as a last resort. If you can use a lazy variable, or provide a default value for a variable – you should do so instead of using an implicitly unwrapped optional.

However, there are a few scenarios where implicitly unwrapped optionals are beneficial, and you are still able to use various ways of safely unwrapping them as listed below – but you should always use them with due caution.


How can I safely deal with Optionals?

The simplest way to check whether an optional contains a value, is to compare it to nil.

if anOptionalInt != nil {
    print("Contains a value!")
} else {
    print("Doesn’t contain a value.")
}

However, 99.9% of the time when working with optionals, you’ll actually want to access the value it contains, if it contains one at all. To do this, you can use Optional Binding.

Optional Binding

Optional Binding allows you to check if an optional contains a value – and allows you to assign the unwrapped value to a new variable or constant. It uses the syntax if let x = anOptional {...} or if var x = anOptional {...}, depending if you need to modify the value of the new variable after binding it.

For example:

if let number = anOptionalInt {
    print("Contains a value! It is \(number)!")
} else {
    print("Doesn’t contain a number")
}

What this does is first check that the optional contains a value. If it does, then the ‘unwrapped’ value is assigned to a new variable (number) – which you can then freely use as if it were non-optional. If the optional doesn’t contain a value, then the else clause will be invoked, as you would expect.

What’s neat about optional binding, is you can unwrap multiple optionals at the same time. You can just separate the statements with a comma. The statement will succeed if all the optionals were unwrapped.

var anOptionalInt : Int?
var anOptionalString : String?

if let number = anOptionalInt, let text = anOptionalString {
    print("anOptionalInt contains a value: \(number). And so does anOptionalString, it’s: \(text)")
} else {
    print("One or more of the optionals don’t contain a value")
}

Another neat trick is that you can also use commas to check for a certain condition on the value, after unwrapping it.

if let number = anOptionalInt, number > 0 {
    print("anOptionalInt contains a value: \(number), and it’s greater than zero!")
}

The only catch with using optional binding within an if statement, is that you can only access the unwrapped value from within the scope of the statement. If you need access to the value from outside of the scope of the statement, you can use a guard statement.

A guard statement allows you to define a condition for success – and the current scope will only continue executing if that condition is met. They are defined with the syntax guard condition else {...}.

So, to use them with an optional binding, you can do this:

guard let number = anOptionalInt else {
    return
}

(Note that within the guard body, you must use one of the control transfer statements in order to exit the scope of the currently executing code).

If anOptionalInt contains a value, it will be unwrapped and assigned to the new number constant. The code after the guard will then continue executing. If it doesn’t contain a value – the guard will execute the code within the brackets, which will lead to transfer of control, so that the code immediately after will not be executed.

The real neat thing about guard statements is the unwrapped value is now available to use in code that follows the statement (as we know that future code can only execute if the optional has a value). This is a great for eliminating ‘pyramids of doom’ created by nesting multiple if statements.

For example:

guard let number = anOptionalInt else {
    return
}

print("anOptionalInt contains a value, and it’s: \(number)!")

Guards also support the same neat tricks that the if statement supported, such as unwrapping multiple optionals at the same time and using the where clause.

Whether you use an if or guard statement completely depends on whether any future code requires the optional to contain a value.

Nil Coalescing Operator

The Nil Coalescing Operator is a nifty shorthand version of the ternary conditional operator, primarily designed to convert optionals to non-optionals. It has the syntax a ?? b, where a is an optional type and b is the same type as a (although usually non-optional).

It essentially lets you say “If a contains a value, unwrap it. If it doesn’t then return b instead”. For example, you could use it like this:

let number = anOptionalInt ?? 0

This will define a number constant of Int type, that will either contain the value of anOptionalInt, if it contains a value, or 0 otherwise.

It’s just shorthand for:

let number = anOptionalInt != nil ? anOptionalInt! : 0

Optional Chaining

You can use Optional Chaining in order to call a method or access a property on an optional. This is simply done by suffixing the variable name with a ? when using it.

For example, say we have a variable foo, of type an optional Foo instance.

var foo : Foo?

If we wanted to call a method on foo that doesn’t return anything, we can simply do:

foo?.doSomethingInteresting()

If foo contains a value, this method will be called on it. If it doesn’t, nothing bad will happen – the code will simply continue executing.

(This is similar behaviour to sending messages to nil in Objective-C)

This can therefore also be used to set properties as well as call methods. For example:

foo?.bar = Bar()

Again, nothing bad will happen here if foo is nil. Your code will simply continue executing.

Another neat trick that optional chaining lets you do is check whether setting a property or calling a method was successful. You can do this by comparing the return value to nil.

(This is because an optional value will return Void? rather than Void on a method that doesn’t return anything)

For example:

if (foo?.bar = Bar()) != nil {
    print("bar was set successfully")
} else {
    print("bar wasn’t set successfully")
}

However, things become a little bit more tricky when trying to access properties or call methods that return a value. Because foo is optional, anything returned from it will also be optional. To deal with this, you can either unwrap the optionals that get returned using one of the above methods – or unwrap foo itself before accessing methods or calling methods that return values.

Also, as the name suggests, you can ‘chain’ these statements together. This means that if foo has an optional property baz, which has a property qux – you could write the following:

let optionalQux = foo?.baz?.qux

Again, because foo and baz are optional, the value returned from qux will always be an optional regardless of whether qux itself is optional.

map and flatMap

An often underused feature with optionals is the ability to use the map and flatMap functions. These allow you to apply non-optional transforms to optional variables. If an optional has a value, you can apply a given transformation to it. If it doesn’t have a value, it will remain nil.

For example, let’s say you have an optional string:

let anOptionalString:String?

By applying the map function to it – we can use the stringByAppendingString function in order to concatenate it to another string.

Because stringByAppendingString takes a non-optional string argument, we cannot input our optional string directly. However, by using map, we can use allow stringByAppendingString to be used if anOptionalString has a value.

For example:

var anOptionalString:String? = "bar"

anOptionalString = anOptionalString.map {unwrappedString in
    return "foo".stringByAppendingString(unwrappedString)
}

print(anOptionalString) // Optional("foobar")

However, if anOptionalString doesn’t have a value, map will return nil. For example:

var anOptionalString:String?

anOptionalString = anOptionalString.map {unwrappedString in
    return "foo".stringByAppendingString(unwrappedString)
}

print(anOptionalString) // nil

flatMap works similarly to map, except it allows you to return another optional from within the closure body. This means you can input an optional into a process that requires a non-optional input, but can output an optional itself.

try!

Swift's error handling system can be safely used with Do-Try-Catch:

do {
    let result = try someThrowingFunc() 
} catch {
    print(error)
}

If someThrowingFunc() throws an error, the error will be safely caught in the catch block.

The error constant you see in the catch block has not been declared by us - it's automatically generated by catch.

You can also declare error yourself, it has the advantage of being able to cast it to a useful format, for example:

do {
    let result = try someThrowingFunc()    
} catch let error as NSError {
    print(error.debugDescription)
}

Using try this way is the proper way to try, catch and handle errors coming from throwing functions.

There's also try? which absorbs the error:

if let result = try? someThrowingFunc() {
    // cool
} else {
    // handle the failure, but there's no error information available
}

But Swift's error handling system also provides a way to "force try" with try!:

let result = try! someThrowingFunc()

The concepts explained in this post also apply here: if an error is thrown, the application will crash.

You should only ever use try! if you can prove that its result will never fail in your context - and this is very rare.

Most of the time you will use the complete Do-Try-Catch system - and the optional one, try?, in the rare cases where handling the error is not important.


Resources

Calling one Activity from another in Android

I used following code on my sample application to start new activity.

Button next = (Button) findViewById(R.id.TEST);
next.setOnClickListener(new View.OnClickListener() {
    public void onClick(View view) {
        Intent myIntent = new Intent( view.getContext(), MyActivity.class);
        startActivityForResult(myIntent, 0);
    }
});

How to iterate over the file in python

You should learn about EAFP vs LBYL.

from sys import stdin, stdout
def main(infile=stdin, outfile=stdout):
    if isinstance(infile, basestring):
        infile=open(infile,'r')
    if isinstance(outfile, basestring):
        outfile=open(outfile,'w')
    for lineno, line in enumerate(infile, 1):
        line = line.strip()
         try:
             print >>outfile, int(line,16)
         except ValueError:
             return "Bad value at line %i: %r" % (lineno, line)

if __name__ == "__main__":
    from sys import argv, exit
    exit(main(*argv[1:]))

SQL Server convert select a column and convert it to a string

+------+----------------------+
| type |        names         |
+------+----------------------+
| cat  | Felon                |
| cat  | Purz                 |
| dog  | Fido                 |
| dog  | Beethoven            |
| dog  | Buddy                |
| bird | Tweety               |
+------+----------------------+

select group_concat(name) from Pets
group by type

Here you can easily get the answer in single SQL and by using group by in your SQL you can separate the result based on that column value. Also you can use your own custom separator for splitting values

Result:

+------+----------------------+
| type |        names         |
+------+----------------------+
| cat  | Felon,Purz           |
| dog  | Fido,Beethoven,Buddy |
| bird | Tweety               |
+------+----------------------+

How do I handle too long index names in a Ruby on Rails ActiveRecord migration?

In PostgreSQL, the default limit is 63 characters. Because index names must be unique it's nice to have a little convention. I use (I tweaked the example to explain more complex constructions):

def change
  add_index :studies, [:professor_id, :user_id], name: :idx_study_professor_user
end

The normal index would have been:

:index_studies_on_professor_id_and_user_id

The logic would be:

  • index becomes idx
  • Singular table name
  • No joining words
  • No _id
  • Alphabetical order

Which usually does the job.

Connect to SQL Server database from Node.js

There is a module on npm called mssqlhelper

You can install it to your project by npm i mssqlhelper

Example of connecting and performing a query:

var db = require('./index');

db.config({
    host: '192.168.1.100'
    ,port: 1433
    ,userName: 'sa'
    ,password: '123'
    ,database:'testdb'
});

db.query(
    'select @Param1 Param1,@Param2 Param2'
    ,{
         Param1: { type : 'NVarChar', size: 7,value : 'myvalue' }
         ,Param2: { type : 'Int',value : 321 }
    }
    ,function(res){
        if(res.err)throw new Error('database error:'+res.err.msg);
        var rows = res.tables[0].rows;
        for (var i = 0; i < rows.length; i++) {
            console.log(rows[i].getValue(0),rows[i].getValue('Param2'));
        }
    }
);

You can read more about it here: https://github.com/play175/mssqlhelper

:o)

Convert string to symbol-able in ruby

This is not answering the question itself, but I found this question searching for the solution to convert a string to symbol and use it on a hash.

hsh = Hash.new
str_to_symbol = "Book Author Title".downcase.gsub(/\s+/, "_").to_sym
hsh[str_to_symbol] = 10
p hsh
# => {book_author_title: 10}

Hope it helps someone like me!

Bootstrap 3 - How to load content in modal body via AJAX?

This is actually super simple with just a little bit of added javascript. The link's href is used as the ajax content source. Note that for Bootstrap 3.* we set data-remote="false" to disable the deprecated Bootstrap load function.

JavaScript:

// Fill modal with content from link href
$("#myModal").on("show.bs.modal", function(e) {
    var link = $(e.relatedTarget);
    $(this).find(".modal-body").load(link.attr("href"));
});

Html (based on the official example):

<!-- Link trigger modal -->
<a href="remoteContent.html" data-remote="false" data-toggle="modal" data-target="#myModal" class="btn btn-default">
    Launch Modal
</a>

<!-- Default bootstrap modal example -->
<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header">
        <button type="button" class="close" data-dismiss="modal" aria-label="Close"><span aria-hidden="true">&times;</span></button>
        <h4 class="modal-title" id="myModalLabel">Modal title</h4>
      </div>
      <div class="modal-body">
        ...
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
        <button type="button" class="btn btn-primary">Save changes</button>
      </div>
    </div>
  </div>
</div>

Try it yourself: https://jsfiddle.net/ednon5d1/

How to add leading zeros for for-loop in shell?

why not printf '%02d' $num? See help printf for this internal bash command.

How to check permissions of a specific directory?

In addition to the above posts, i'd like to point out that "man ls" will give you a nice manual about the "ls" ( List " command.

Also, using ls -la myFile will list & show all the facts about that file.

Origin http://localhost is not allowed by Access-Control-Allow-Origin

If you are making the fetch call to your localhost which I'm guessing is run by node.js in the same directory as your backbone code, than it will most likely be on http://localhost:3000 or something like that. Than this should be your model:

var model = Backbone.Model.extend({
    url: '/item'
});

And in your node.js you now have to accept that call like this:

app.get('/item', function(req, res){
    res.send('some info here');
});