Programs & Examples On #Luke

Luke is a development and diagnostic tool, which accesses already existing Lucene indexes and allows you to display and modify their content.

use Lodash to sort array of object by value

You can use lodash sortBy (https://lodash.com/docs/4.17.4#sortBy).

Your code could be like:

const myArray = [  
   {  
      "id":25,
      "name":"Anakin Skywalker",
      "createdAt":"2017-04-12T12:48:55.000Z",
      "updatedAt":"2017-04-12T12:48:55.000Z"
   },
   {  
      "id":1,
      "name":"Luke Skywalker",
      "createdAt":"2017-04-12T11:25:03.000Z",
      "updatedAt":"2017-04-12T11:25:03.000Z"
   }
]

const myOrderedArray = _.sortBy(myArray, o => o.name)

Typescript: TS7006: Parameter 'xxx' implicitly has an 'any' type

Very sort cut and effective solution is below:-

Add the below rule in your tsconfig.json file:-

"noImplicitAny": false

Then restart your project.

Clone private git repo with dockerfile

There's no need to fiddle around with ssh configurations. Use a configuration file (not a Dockerfile) that contains environment variables, and have a shell script update your docker file at runtime. You keep tokens out of your Dockerfiles and you can clone over https (no need to generate or pass around ssh keys).

Go to Settings > Personal Access Tokens

  • Generate a personal access token with repo scope enabled.
  • Clone like this: git clone https://[email protected]/user-or-org/repo

Some commenters have noted that if you use a shared Dockerfile, this could expose your access key to other people on your project. While this may or may not be a concern for your specific use case, here are some ways you can deal with that:

  • Use a shell script to accept arguments which could contain your key as a variable. Replace a variable in your Dockerfile with sed or similar, i.e. calling the script with sh rundocker.sh MYTOKEN=foo which would replace on https://{{MY_TOKEN}}@github.com/user-or-org/repo. Note that you could also use a configuration file (in .yml or whatever format you want) to do the same thing but with environment variables.
  • Create a github user (and generate an access token for) for that project only

AngularJS : Factory and Service?

Factory and Service is a just wrapper of a provider.

Factory

Factory can return anything which can be a class(constructor function), instance of class, string, number or boolean. If you return a constructor function, you can instantiate in your controller.

 myApp.factory('myFactory', function () {

  // any logic here..

  // Return any thing. Here it is object
  return {
    name: 'Joe'
  }
}

Service

Service does not need to return anything. But you have to assign everything in this variable. Because service will create instance by default and use that as a base object.

myApp.service('myService', function () {

  // any logic here..

  this.name = 'Joe';
}

Actual angularjs code behind the service

function service(name, constructor) {
    return factory(name, ['$injector', function($injector) {
        return $injector.instantiate(constructor);
    }]);
}

It just a wrapper around the factory. If you return something from service, then it will behave like Factory.

IMPORTANT: The return result from Factory and Service will be cache and same will be returned for all controllers.

When should i use them?

Factory is mostly preferable in all cases. It can be used when you have constructor function which needs to be instantiated in different controllers.

Service is a kind of Singleton Object. The Object return from Service will be same for all controller. It can be used when you want to have single object for entire application. Eg: Authenticated user details.

For further understanding, read

http://iffycan.blogspot.in/2013/05/angular-service-or-factory.html

http://viralpatel.net/blogs/angularjs-service-factory-tutorial/

Python name 'os' is not defined

The problem is that you forgot to import os. Add this line of code:

import os

And everything should be fine. Hope this helps!

How to SUM parts of a column which have same text value in different column in the same row

This can be done by using SUMPRODUCT as well. Update the ranges as you see fit

=SUMPRODUCT(($A$2:$A$7=A2)*($B$2:$B$7=B2)*$C$2:$C$7)

A2:A7 = First name range

B2:B7 = Last Name Range

C2:C7 = Numbers Range

This will find all the names with the same first and last name and sum the numbers in your numbers column

Python: SyntaxError: non-keyword after keyword arg

To really get this clear, here's my for-beginners answer: You inputed the arguments in the wrong order.
A keyword argument has this style:

nullable=True, unique=False

A fixed parameter should be defined: True, False, etc. A non-keyword argument is different:

name="Ricardo", fruit="chontaduro" 

This syntax error asks you to first put name="Ricardo" and all of its kind (non-keyword) before those like nullable=True.

How to add color to Github's README.md file

Based on @AlecRust idea, I did an implementation of png text service.

The demo is here:

http://lingtalfi.com/services/pngtext?color=cc0000&size=10&text=Hello%20World

There are four parameters:

  • text: the string to display
  • font: not use because I only have Arial.ttf anyway on this demo.
  • fontSize: an integer (defaults to 12)
  • color: a 6 chars hexadecimal code

Please do not use this service directly (except for testing), but use the class I created that provides the service:

https://github.com/lingtalfi/WebBox/blob/master/Image/PngTextUtil.php

class PngTextUtil
{
    /**
     * Displays a png text.
     *
     * Note: this method is meant to be used as a webservice.
     *
     * Options:
     * ------------
     * - font: string = arial/Arial.ttf
     *          The font to use.
     *          If the path starts with a slash, it's an absolute path to the font file.
     *          Else if the path doesn't start with a slash, it's a relative path to the font directory provided
     *          by this class (the WebBox/assets/fonts directory in this repository).
     * - fontSize: int = 12
     *          The font size.
     * - color: string = 000000
     *          The color of the text in hexadecimal format (6 chars).
     *          This can optionally be prefixed with a pound symbol (#).
     *
     *
     *
     *
     *
     *
     * @param string $text
     * @param array $options
     * @throws \Bat\Exception\BatException
     * @throws WebBoxException
     */
    public static function displayPngText(string $text, array $options = []): void
    {
        if (false === extension_loaded("gd")) {
            throw new WebBoxException("The gd extension is not loaded!");
        }
        header("Content-type: image/png");
        $font = $options['font'] ?? "arial/Arial.ttf";
        $fontsize = $options['fontSize'] ?? 12;
        $hexColor = $options['color'] ?? "000000";
        if ('/' !== substr($font, 0, 1)) {
            $fontDir = __DIR__ . "/../assets/fonts";
            $font = $fontDir . "/" . $font;
        }
        $rgbColors = ConvertTool::convertHexColorToRgb($hexColor);
        //--------------------------------------------
        // GET THE TEXT BOX DIMENSIONS
        //--------------------------------------------
        $charWidth = $fontsize;
        $charFactor = 1;
        $textLen = mb_strlen($text);
        $imageWidth = $textLen * $charWidth * $charFactor;
        $imageHeight = $fontsize;
        $logoimg = imagecreatetruecolor($imageWidth, $imageHeight);
        imagealphablending($logoimg, false);
        imagesavealpha($logoimg, true);
        $col = imagecolorallocatealpha($logoimg, 255, 255, 255, 127);
        imagefill($logoimg, 0, 0, $col);
        $white = imagecolorallocate($logoimg, $rgbColors[0], $rgbColors[1], $rgbColors[2]); //for font color
        $x = 0;
        $y = $fontsize;
        $angle = 0;
        $bbox = imagettftext($logoimg, $fontsize, $angle, $x, $y, $white, $font, $text); //fill text in your image
        $boxWidth = $bbox[4] - $bbox[0];
        $boxHeight = $bbox[7] - $bbox[1];
        imagedestroy($logoimg);
        //--------------------------------------------
        // CREATE THE PNG
        //--------------------------------------------
        $imageWidth = abs($boxWidth);
        $imageHeight = abs($boxHeight);
        $logoimg = imagecreatetruecolor($imageWidth, $imageHeight);
        imagealphablending($logoimg, false);
        imagesavealpha($logoimg, true);
        $col = imagecolorallocatealpha($logoimg, 255, 255, 255, 127);
        imagefill($logoimg, 0, 0, $col);
        $white = imagecolorallocate($logoimg, $rgbColors[0], $rgbColors[1], $rgbColors[2]); //for font color
        $x = 0;
        $y = $fontsize;
        $angle = 0;
        imagettftext($logoimg, $fontsize, $angle, $x, $y, $white, $font, $text); //fill text in your image
        imagepng($logoimg); //save your image at new location $target
        imagedestroy($logoimg);
    }
}

Note: if you don't use the universe framework, you will need to replace this line:

$rgbColors = ConvertTool::convertHexColorToRgb($hexColor);

With this code:

$rgbColors = sscanf($hexColor, "%02x%02x%02x");

In which case your hex color must be exactly 6 chars long (don't put the hash symbol (#) in front of it).

Note: in the end, I did not use this service, because I found that the font was ugly and worse: it was not possible to select the text. But for the sake of this discussion I thought this code was worth sharing...

How do I access an access array item by index in handlebars?

Please try this, if you want to fetch first/last.

{{#each list}}

    {{#if @first}}
        <div class="active">
    {{else}}
        <div>
    {{/if}}

{{/each}}


{{#each list}}

    {{#if @last}}
        <div class="last-element">
    {{else}}
        <div>
    {{/if}}

{{/each}}

Fast and Lean PDF Viewer for iPhone / iPad / iOS - tips and hints?

For a simple and effective PDF viewer, when you require only limited functionality, you can now (iOS 4.0+) use the QuickLook framework:

First, you need to link against QuickLook.framework and #import <QuickLook/QuickLook.h>;

Afterwards, in either viewDidLoad or any of the lazy initialization methods:

QLPreviewController *previewController = [[QLPreviewController alloc] init];
previewController.dataSource = self;
previewController.delegate = self;
previewController.currentPreviewItemIndex = indexPath.row;
[self presentModalViewController:previewController animated:YES];
[previewController release];

WCF timeout exception detailed investigation

I'm having a very similar problem. In the past, this has been related to serialization problems. If you are still having this problem, can you verify that you can correctly serialize the objects you are returning. Specifically, if you are using Linq-To-Sql objects that have relationships, there are known serialization problems if you put a back reference on a child object to the parent object and mark that back reference as a DataMember.

You can verify serialization by writing a console app that serializes and deserializes your objects using the DataContractSerializer on the server side and whatever serialization methods your client uses. For example, in our current application, we have both WPF and Compact Framework clients. I wrote a console app to verify that I can serialize using a DataContractSerializer and deserialize using an XmlDesserializer. You might try that.

Also, if you are returning Linq-To-Sql objects that have child collections, you might try to ensure that you have eagerly loaded them on the server side. Sometimes, because of lazy loading, the objects being returned are not populated and may cause the behavior you are seeing where the request is sent to the service method multiple times.

If you have solved this problem, I'd love to hear how because I'm stuck with it too. I have verified that my issue is not serialization so I'm at a loss.

UPDATE: I'm not sure if it will help you any but the Service Trace Viewer Tool just solved my problem after 5 days of very similar experience to yours. By setting up tracing and then looking at the raw XML, I found the exceptions that were causing my serialization problems. It was related to Linq-to-SQL objects that occasionally had more child objects than could be successfully serialized. Adding the following to your web.config file should enable tracing:

<sharedListeners>
    <add name="sharedListener"
         type="System.Diagnostics.XmlWriterTraceListener"
         initializeData="c:\Temp\servicetrace.svclog" />
  </sharedListeners>
  <sources>
    <source name="System.ServiceModel" switchValue="Verbose, ActivityTracing" >
      <listeners>
        <add name="sharedListener" />
      </listeners>
    </source>
    <source name="System.ServiceModel.MessageLogging" switchValue="Verbose">
      <listeners>
        <add name="sharedListener" />
      </listeners>
    </source>
  </sources>

The resulting file can be opened with the Service Trace Viewer Tool or just in IE to examine the results.

At runtime, find all classes in a Java application that extend a base class

I use org.reflections:

Reflections reflections = new Reflections("com.mycompany");    
Set<Class<? extends MyInterface>> classes = reflections.getSubTypesOf(MyInterface.class);

Another example:

public static void main(String[] args) throws IllegalAccessException, InstantiationException {
    Reflections reflections = new Reflections("java.util");
    Set<Class<? extends List>> classes = reflections.getSubTypesOf(java.util.List.class);
    for (Class<? extends List> aClass : classes) {
        System.out.println(aClass.getName());
        if(aClass == ArrayList.class) {
            List list = aClass.newInstance();
            list.add("test");
            System.out.println(list.getClass().getName() + ": " + list.size());
        }
    }
}

How to easily duplicate a Windows Form in Visual Studio?

Its Really Easy. "In Design mode FORM" (form1.cs[Design]) copy the whole Form "ctrl A" then ctrl C. All objects at once. Then add a new windows form to the project. Change the size of the form to the size that you want then paste ctrl V all of the new objects will be copied to the new form. When they are all still picked double click on any of the objects. NOT THE FORM!!!..... This will create the code on the Form side matching the objects you just pasted. if it doesn't you can double click on each object and it will create the code one at a time. I use a text box area to double click in and it works almost every time. I use this method everyday WORKS GREAT.

Get value of a merged cell of an excel from its cell address in vba

Even if it is really discouraged to use merge cells in Excel (use Center Across Selection for instance if needed), the cell that "contains" the value is the one on the top left (at least, that's a way to express it).

Hence, you can get the value of merged cells in range B4:B11 in several ways:

  • Range("B4").Value
  • Range("B4:B11").Cells(1).Value
  • Range("B4:B11").Cells(1,1).Value

You can also note that all the other cells have no value in them. While debugging, you can see that the value is empty.

Also note that Range("B4:B11").Value won't work (raises an execution error number 13 if you try to Debug.Print it) because it returns an array.

Disable developer mode extensions pop up in Chrome

The official way to disable the popup is this:

  1. Pack your extension: go to chrome://extensions, check Developer mode and click Pack extension

  2. Install the extension by dragging and dropping the .crx file into the chrome://extensions page.

You'll get an "Unsupported extensions disabled" popup if you try restarting Chrome at this point.

Then for Windows 7 or Windows 8:

  1. Download Chrome group policy templates here
  2. Copy [zip]\windows\admx\chrome.admx to c:\windows\policydefinitions
  3. Copy [zip]\windows\admx\[yourlanguage]\chrome.adml to c:\windows\policydefinitions\[yourlanguage]\chrome.adml (not c:\windows\[yourlanguage])
  4. In Chrome, go to the Extensions page: chrome://extensions
  5. Check Developer Mode
  6. Scroll down the list of disabled extensions and note the ID(s) of the extensions you want to enable.
  7. Click Start > Run, type gpedit.msc and hit enter.
  8. Click User Configuration > Administrative Templates > Google Chrome > Extensions
  9. Double click Configure extension installation whitelist policy
  10. Select Enabled, and click Show
  11. In the list, enter the ID(s) of the extensions you noted in Step 7
  12. Click OK and restart Chrome.

That's it!

EDIT: As of July 2018, this approach no longer works: it seems Google has stopped honouring the "whitelist".

EDIT 2: As of December 2018, this approach works in Chrome Version 69.0.3497.100 (Official Build) (64-bit):

  1. Temporarily enable Developer mode in chrome://extensions

  2. Uninstall the extension that causes the popup using the Load unpacked.

  3. Click on Pack extension, and find and select the folder containing the extension files. Don't enter the private key file if you don't have it.

  4. Click Pack extension. A .crx and .pem file will be created near the root directory of the extension. Install the extension using the .crx file and keep the .pem file safe.

  5. Copy the .crx installed extension ID to the whitelist and restart Chrome.

The popup should be gone.

Change directory in PowerShell

Multiple posted answer here, but probably this can help who is newly using PowerShell

enter image description here

SO if any space is there in your directory path do not forgot to add double inverted commas "".

How do I watch a file for changes?

ACTIONS = {
  1 : "Created",
  2 : "Deleted",
  3 : "Updated",
  4 : "Renamed from something",
  5 : "Renamed to something"
}
FILE_LIST_DIRECTORY = 0x0001

class myThread (threading.Thread):
    def __init__(self, threadID, fileName, directory, origin):
        threading.Thread.__init__(self)
        self.threadID = threadID
        self.fileName = fileName
        self.daemon = True
        self.dir = directory
        self.originalFile = origin
    def run(self):
        startMonitor(self.fileName, self.dir, self.originalFile)

def startMonitor(fileMonitoring,dirPath,originalFile):
    hDir = win32file.CreateFile (
        dirPath,
        FILE_LIST_DIRECTORY,
        win32con.FILE_SHARE_READ | win32con.FILE_SHARE_WRITE,
        None,
        win32con.OPEN_EXISTING,
        win32con.FILE_FLAG_BACKUP_SEMANTICS,
        None
    )
    # Wait for new data and call ProcessNewData for each new chunk that's
    # written
    while 1:
        # Wait for a change to occur
        results = win32file.ReadDirectoryChangesW (
            hDir,
            1024,
            False,
            win32con.FILE_NOTIFY_CHANGE_LAST_WRITE,
            None,
            None
        )
        # For each change, check to see if it's updating the file we're
        # interested in
        for action, file_M in results:
            full_filename = os.path.join (dirPath, file_M)
            #print file, ACTIONS.get (action, "Unknown")
            if len(full_filename) == len(fileMonitoring) and action == 3:
                #copy to main file
                ...

Sort tuples based on second parameter

You can use the key parameter to list.sort():

my_list.sort(key=lambda x: x[1])

or, slightly faster,

my_list.sort(key=operator.itemgetter(1))

(As with any module, you'll need to import operator to be able to use it.)

How to initialize a dict with keys from a list and empty value in Python?

default_keys = [1, "name"]

To get dictionary with None as values:

dict.fromkeys(default_keys)  

Output :

{1: None, 'name': None}

To get dictionary with default values:

dict.fromkeys(default_keys, [])  

Output :

{1: [], 'name': []}

Where is JAVA_HOME on macOS Mojave (10.14) to Lion (10.7)?

For Mac Yosemite,

JDK 1.7.0_xx is using

$ ls -ltar /usr/bin/java
/System/Library/Frameworks/JavaVM.framework/Versions/Current/Commands/java

JAVA_HOME

/Library/Java/JavaVirtualMachines/jdk1.7.0_xx.jdk/Contents/Home

Deleting a pointer in C++

I believe you're not fully understanding how pointers work.
When you have a pointer pointing to some memory there are three different things you must understand:
- there is "what is pointed" by the pointer (the memory)
- this memory address
- not all pointers need to have their memory deleted: you only need to delete memory that was dynamically allocated (used new operator).

Imagine:

int *ptr = new int; 
// ptr has the address of the memory.
// at this point, the actual memory doesn't have anything.
*ptr = 8;
// you're assigning the integer 8 into that memory.
delete ptr;
// you are only deleting the memory.
// at this point the pointer still has the same memory address (as you could
//   notice from your 2nd test) but what inside that memory is gone!

When you did

ptr = NULL;
// you didn't delete the memory
// you're only saying that this pointer is now pointing to "nowhere".
// the memory that was pointed by this pointer is now lost.

C++ allows that you try to delete a pointer that points to null but it doesn't actually do anything, just doesn't give any error.

Generate sql insert script from excel worksheet

I had to make SQL scripts often and add them to source control and send them to DBA. I used this ExcelIntoSQL App from windows store https://www.microsoft.com/store/apps/9NH0W51XXQRM It creates complete script with "CREATE TABLE" and INSERTS.

How do I add an integer value with javascript (jquery) to a value that's returning a string?

parseInt() will force it to be type integer, or will be NaN (not a number) if it cannot perform the conversion.

var currentValue = parseInt($("#replies").text(),10);

The second paramter (radix) makes sure it is parsed as a decimal number.

Difference between static memory allocation and dynamic memory allocation

Static memory allocation. Memory allocated will be in stack.

int a[10];

Dynamic memory allocation. Memory allocated will be in heap.

int *a = malloc(sizeof(int) * 10);

and the latter should be freed since there is no Garbage Collector(GC) in C.

free(a);

Single controller with multiple GET methods in ASP.NET Web API

Simple Alternative

Just use a query string.

Routing

config.Routes.MapHttpRoute(
    name: "DefaultApi",
    routeTemplate: "api/{controller}/{id}",
    defaults: new { id = RouteParameter.Optional }
);

Controller

public class TestController : ApiController
{
    public IEnumerable<SomeViewModel> Get()
    {
    }

    public SomeViewModel GetById(int objectId)
    {
    }
}

Requests

GET /Test
GET /Test?objectId=1

Note

Keep in mind that the query string param should not be "id" or whatever the parameter is in the configured route.

How to change the length of a column in a SQL Server table via T-SQL

So, let's say you have this table:

CREATE TABLE YourTable(Col1 VARCHAR(10))

And you want to change Col1 to VARCHAR(20). What you need to do is this:

ALTER TABLE YourTable
ALTER COLUMN Col1 VARCHAR(20)

That'll work without problems since the length of the column got bigger. If you wanted to change it to VARCHAR(5), then you'll first gonna need to make sure that there are not values with more chars on your column, otherwise that ALTER TABLE will fail.

Laravel 5 not finding css files

Simply you can put a back slash in front of your css link

How do I get information about an index and table owner in Oracle?

 select index_name, column_name
 from user_ind_columns
 where table_name = 'NAME';

OR use this:

select TABLE_NAME, OWNER 
from SYS.ALL_TABLES 
order by OWNER, TABLE_NAME 

And for Indexes:

select INDEX_NAME, TABLE_NAME, TABLE_OWNER 
from SYS.ALL_INDEXES 
order by TABLE_OWNER, TABLE_NAME, INDEX_NAME

Convert a float64 to an int in Go

package main
import "fmt"
func main() {
  var x float64 = 5.7
  var y int = int(x)
  fmt.Println(y)  // outputs "5"
}

How to stop creating .DS_Store on Mac?

Put following line into your ".profile" file.

Open .profile file and copy this line

find ~/ -name '.DS_Store' -delete

When you open terminal window it will automatically delete your .DS_Store file for you.

How to import js-modules into TypeScript file?

I've been facing this problem for long but what this solves my problem Go inside the tsconfig.json and add the following under compilerOptions

{
  "compilerOptions": {
      ...
      "allowJs": true
      ...
  }
}

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

Everyone knows (hopefully) its bad to terminate thread. The problem is when you don't own a piece of code you're calling. If this code is running in some do/while infinite loop , itself calling some native functions, etc. you're basically stuck. When this happens in your own code termination, stop or Dispose call, it's kinda ok to start shooting the bad guys (so you don't become a bad guy yourself).

So, for what it's worth, I've written those two blocking functions that use their own native thread, not a thread from the pool or some thread created by the CLR. They will stop the thread if a timeout occurs:

// returns true if the call went to completion successfully, false otherwise
public static bool RunWithAbort(this Action action, int milliseconds) => RunWithAbort(action, new TimeSpan(0, 0, 0, 0, milliseconds));
public static bool RunWithAbort(this Action action, TimeSpan delay)
{
    if (action == null)
        throw new ArgumentNullException(nameof(action));

    var source = new CancellationTokenSource(delay);
    var success = false;
    var handle = IntPtr.Zero;
    var fn = new Action(() =>
    {
        using (source.Token.Register(() => TerminateThread(handle, 0)))
        {
            action();
            success = true;
        }
    });

    handle = CreateThread(IntPtr.Zero, IntPtr.Zero, fn, IntPtr.Zero, 0, out var id);
    WaitForSingleObject(handle, 100 + (int)delay.TotalMilliseconds);
    CloseHandle(handle);
    return success;
}

// returns what's the function should return if the call went to completion successfully, default(T) otherwise
public static T RunWithAbort<T>(this Func<T> func, int milliseconds) => RunWithAbort(func, new TimeSpan(0, 0, 0, 0, milliseconds));
public static T RunWithAbort<T>(this Func<T> func, TimeSpan delay)
{
    if (func == null)
        throw new ArgumentNullException(nameof(func));

    var source = new CancellationTokenSource(delay);
    var item = default(T);
    var handle = IntPtr.Zero;
    var fn = new Action(() =>
    {
        using (source.Token.Register(() => TerminateThread(handle, 0)))
        {
            item = func();
        }
    });

    handle = CreateThread(IntPtr.Zero, IntPtr.Zero, fn, IntPtr.Zero, 0, out var id);
    WaitForSingleObject(handle, 100 + (int)delay.TotalMilliseconds);
    CloseHandle(handle);
    return item;
}

[DllImport("kernel32")]
private static extern bool TerminateThread(IntPtr hThread, int dwExitCode);

[DllImport("kernel32")]
private static extern IntPtr CreateThread(IntPtr lpThreadAttributes, IntPtr dwStackSize, Delegate lpStartAddress, IntPtr lpParameter, int dwCreationFlags, out int lpThreadId);

[DllImport("kernel32")]
private static extern bool CloseHandle(IntPtr hObject);

[DllImport("kernel32")]
private static extern int WaitForSingleObject(IntPtr hHandle, int dwMilliseconds);

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

You can see which version gets executed when you load the page with Google Chrome + developer tools (preinstalled) or Firefox + Firebug (add-on).

I use Google Chrome:

  1. Open Chrome and use Ctrl+Shift+I to open the developer tools.
  2. Go to the "Network" Tab
  3. Click on the small button at the bottom "Preserve log upon Navigation"
  4. Load any of your pages
  5. Click on the response header

It looks like this:

enter image description here

Why doesn't adding CORS headers to an OPTIONS route allow browsers to access my API?

The easiest answer is to just use the cors package.

const cors = require('cors');

const app = require('express')();
app.use(cors());

That will enable CORS across the board. If you want to learn how to enable CORS without outside modules, all you really need is some Express middleware that sets the 'Access-Control-Allow-Origin' header. That's the minimum you need to allow cross-request domains from a browser to your server.

app.options('*', (req, res) => {
  res.set('Access-Control-Allow-Origin', '*');
  res.send('ok');
});

app.use((req, res) => {
  res.set('Access-Control-Allow-Origin', '*');
});

Call static method with reflection

As the documentation for MethodInfo.Invoke states, the first argument is ignored for static methods so you can just pass null.

foreach (var tempClass in macroClasses)
{
   // using reflection I will be able to run the method as:
   tempClass.GetMethod("Run").Invoke(null, null);
}

As the comment points out, you may want to ensure the method is static when calling GetMethod:

tempClass.GetMethod("Run", BindingFlags.Public | BindingFlags.Static).Invoke(null, null);

Flutter command not found

Use the following steps for setup

  1. Download from Flutter SDK for Mac https://flutter.dev/docs/get-started/install/macos

  2. Extract the Flutter SDK zip (saved in Downloads) file using terminal. If you want to extract the Flutter SDK in fluttrerDevelopment folder

    $ cd ~/fluttrerDevelopment

    $ unzip ~/Downloads/flutter_macos_1.20.1-stable.zip

  3. Add the flutter tool to your path:

    $ export PATH=“$PATH:pwd/flutter/bin"

  4. If you have only Xcode setup in your machine then run

    $ flutter create my_first_flutter_app

    $ cd my_first_flutter_app

    $ flutter run

How to install a private NPM module without my own registry?

Npm now provides unlimited private hosted modules for $7/user/month used like so

cd private-project
npm login

in your package json set "name": " @username/private-project"

npm publish

then to require your project:

cd ../new-project
npm install --save @username/private-project

C# Public Enums in Classes

Just declare the enum outside the bounds of the class. Like this:

public enum card_suits
{
    Clubs,
    Hearts,
    Spades,
    Diamonds
}

public class Card
{
    ...
}

Remember that an enum is a type. You might also consider putting the enum in its own file if it's going to be used by other classes. (You're programming a card game and the suit is a very important attribute of the card that, in well-structured code, will need to be accessible by a number of classes.)

org.hibernate.QueryException: could not resolve property: filename

Hibernate queries are case sensitive with property names (because they end up relying on getter/setter methods on the @Entity).

Make sure you refer to the property as fileName in the Criteria query, not filename.

Specifically, Hibernate will call the getter method of the filename property when executing that Criteria query, so it will look for a method called getFilename(). But the property is called FileName and the getter getFileName().

So, change the projection like so:

criteria.setProjection(Projections.property("fileName"));

How do I write good/correct package __init__.py files

__all__ is very good - it helps guide import statements without automatically importing modules http://docs.python.org/tutorial/modules.html#importing-from-a-package

using __all__ and import * is redundant, only __all__ is needed

I think one of the most powerful reasons to use import * in an __init__.py to import packages is to be able to refactor a script that has grown into multiple scripts without breaking an existing application. But if you're designing a package from the start. I think it's best to leave __init__.py files empty.

for example:

foo.py - contains classes related to foo such as fooFactory, tallFoo, shortFoo

then the app grows and now it's a whole folder

foo/
    __init__.py
    foofactories.py
    tallFoos.py
    shortfoos.py
    mediumfoos.py
    santaslittlehelperfoo.py
    superawsomefoo.py
    anotherfoo.py

then the init script can say

__all__ = ['foofactories', 'tallFoos', 'shortfoos', 'medumfoos',
           'santaslittlehelperfoo', 'superawsomefoo', 'anotherfoo']
# deprecated to keep older scripts who import this from breaking
from foo.foofactories import fooFactory
from foo.tallfoos import tallFoo
from foo.shortfoos import shortFoo

so that a script written to do the following does not break during the change:

from foo import fooFactory, tallFoo, shortFoo

Plotting lines connecting points

I think you're going to need separate lines for each segment:

import numpy as np
import matplotlib.pyplot as plt

x, y = np.random.random(size=(2,10))

for i in range(0, len(x), 2):
    plt.plot(x[i:i+2], y[i:i+2], 'ro-')

plt.show()

(The numpy import is just to set up some random 2x10 sample data)

enter image description here

How to write a comment in a Razor view?

This comment syntax should work for you:

@* enter comments here *@

How to view the committed files you have not pushed yet?

Here you'll find your answer:

Using Git how do I find changes between local and remote

For the lazy:

  1. Use "git log origin..HEAD"
  2. Use "git fetch" followed by "git log HEAD..origin". You can cherry-pick individual commits using the listed commit ids.

The above assumes, of course, that "origin" is the name of your remote tracking branch (which it is if you've used clone with default options).

Xcode couldn't find any provisioning profiles matching

You can get this issue if Apple update their terms. Simply log into your dev account and accept any updated terms and you should be good (you will need to goto Xcode -> project->signing and capabilities and retry the certificate check. This should get you going if terms are the issue.

How do I ignore a directory with SVN?

Set the svn:ignore property of the parent directory:

svn propset svn:ignore dirname .

If you have multiple things to ignore, separate by newlines in the property value. In that case it's easier to edit the property value using an external editor:

svn propedit svn:ignore .

Numpy: Divide each row by a vector element

As has been mentioned, slicing with None or with np.newaxes is a great way to do this. Another alternative is to use transposes and broadcasting, as in

(data.T - vector).T

and

(data.T / vector).T

For higher dimensional arrays you may want to use the swapaxes method of NumPy arrays or the NumPy rollaxis function. There really are a lot of ways to do this.

For a fuller explanation of broadcasting, see http://docs.scipy.org/doc/numpy/user/basics.broadcasting.html

How to embed PDF file with responsive width

If you're using Bootstrap 3, you can use the embed-responsive class and set the padding bottom as the height divided by the width plus a little extra for toolbars. For example, to display an 8.5 by 11 PDF, use 130% (11/8.5) plus a little extra (20%).

<div class='embed-responsive' style='padding-bottom:150%'>
    <object data='URL.pdf' type='application/pdf' width='100%' height='100%'></object>
</div>

Here's the Bootstrap CSS:

.embed-responsive {
    position: relative;
    display: block;
    height: 0;
    padding: 0;
    overflow: hidden;
}

Simulate string split function in Excel formula

Highlight the cell, use Dat => Text to Columns and the DELIMITER is space. Result will appear in as many columns as the split find the space.

Calculate a Running Total in SQL Server

SELECT TOP 25   amount, 
    (SELECT SUM(amount) 
    FROM time_detail b 
    WHERE b.time_detail_id <= a.time_detail_id) AS Total FROM time_detail a

You can also use the ROW_NUMBER() function and a temp table to create an arbitrary column to use in the comparison on the inner SELECT statement.

Docker: adding a file from a parent directory

With docker-compose, you could set context folder:

#docker-compose.yml
version: '3.3'    
services:
      yourservice:
        build:
          context: ./
          dockerfile: ./docker/yourservice/Dockerfile

How do you clear a slice in Go?

Setting the slice to nil is the best way to clear a slice. nil slices in go are perfectly well behaved and setting the slice to nil will release the underlying memory to the garbage collector.

See playground

package main

import (
    "fmt"
)

func dump(letters []string) {
    fmt.Println("letters = ", letters)
    fmt.Println(cap(letters))
    fmt.Println(len(letters))
    for i := range letters {
        fmt.Println(i, letters[i])
    }
}

func main() {
    letters := []string{"a", "b", "c", "d"}
    dump(letters)
    // clear the slice
    letters = nil
    dump(letters)
    // add stuff back to it
    letters = append(letters, "e")
    dump(letters)
}

Prints

letters =  [a b c d]
4
4
0 a
1 b
2 c
3 d
letters =  []
0
0
letters =  [e]
1
1
0 e

Note that slices can easily be aliased so that two slices point to the same underlying memory. The setting to nil will remove that aliasing.

This method changes the capacity to zero though.

How to count instances of character in SQL Column

In SQL Server:

SELECT LEN(REPLACE(myColumn, 'N', '')) 
FROM ...

Delete rows with foreign key in PostgreSQL

It means that in table kontakty you have a row referencing the row in osoby you want to delete. You have do delete that row first or set a cascade delete on the relation between tables.

Powodzenia!

How can I detect if Flash is installed and if not, display a hidden div that informs the user?

You can use navigator.mimeTypes.

if (navigator.mimeTypes ["application/x-shockwave-flash"] == undefined)
    $("#someDiv").show ();

Convert Unicode to ASCII without errors in Python

I think the answer is there but only in bits and pieces, which makes it difficult to quickly fix the problem such as

UnicodeDecodeError: 'ascii' codec can't decode byte 0xa0 in position 2818: ordinal not in range(128)

Let's take an example, Suppose I have file which has some data in the following form ( containing ascii and non-ascii chars )

1/10/17, 21:36 - Land : Welcome ��

and we want to ignore and preserve only ascii characters.

This code will do:

import unicodedata
fp  = open(<FILENAME>)
for line in fp:
    rline = line.strip()
    rline = unicode(rline, "utf-8")
    rline = unicodedata.normalize('NFKD', rline).encode('ascii','ignore')
    if len(rline) != 0:
        print rline

and type(rline) will give you

>type(rline) 
<type 'str'>

Formatting numbers (decimal places, thousands separators, etc) with CSS

I don't think you can. You could use number_format() if you're coding in PHP. And other programing languages have a function for formatting numbers too.

Electron: jQuery is not defined

Another way of writing <script>window.$ = window.jQuery = require('./path/to/jquery');</script> is :

<script src="./path/to/jquery" onload="window.$ = window.jQuery = module.exports;"></script>

VBA procedure to import csv file into access

The easiest way to do it is to link the CSV-file into the Access database as a table. Then you can work on this table as if it was an ordinary access table, for instance by creating an appropriate query based on this table that returns exactly what you want.

You can link the table either manually or with VBA like this

DoCmd.TransferText TransferType:=acLinkDelim, TableName:="tblImport", _
    FileName:="C:\MyData.csv", HasFieldNames:=true

UPDATE

Dim db As DAO.Database

' Re-link the CSV Table
Set db = CurrentDb
On Error Resume Next:   db.TableDefs.Delete "tblImport":   On Error GoTo 0
db.TableDefs.Refresh
DoCmd.TransferText TransferType:=acLinkDelim, TableName:="tblImport", _
    FileName:="C:\MyData.csv", HasFieldNames:=true
db.TableDefs.Refresh

' Perform the import
db.Execute "INSERT INTO someTable SELECT col1, col2, ... FROM tblImport " _
   & "WHERE NOT F1 IN ('A1', 'A2', 'A3')"
db.Close:   Set db = Nothing

OS X Framework Library not loaded: 'Image not found'

None of these issues solved this for me. The problem in the end was pretty easy. It looks like its a pretty major Xcode bug which I have logged the problem and fix under Apple bug: 29820370. If you are struggling (as it seems like there are several pages of problems similar to this ) then it would be great if you can raise a bug on bug reporter: https://bugreport.apple.com/ and reference the bug I raised to gain visibility. I want to make Xcode back into the pleasure that it was before - and this is something I am sure Xcode should have fixed itself.

Here is the fix: 1. Open Keychain - go to Apple Worldwide Developer Cert. 2. Double Click on it 3. Change the permission level from "always trust" to use System Defaults 4. Save and close it 5. Restart Xcode, Clean and build your project and it should be gone.

Screenshot below of the correct settings: Keychain access fixed Hope this helps!

How to get the real and total length of char * (char array)?

You can implement your own new and delete functions, as well as an additional get-size function:

#define CEIL_DIV(x,y) (((x)-1)/(y)+1)

void* my_new(int size)
{
    if (size > 0)
    {
        int* ptr = new int[1+CEIL_DIV(size,sizeof(int))];
        if (ptr)
        {
            ptr[0] = size;
            return ptr+1;
        }
    }
    return 0;
}

void my_delete(void* mem)
{
    int* ptr = (int*)mem-1;
    delete ptr;
}

int my_size(void* mem)
{
    int* ptr = (int*)mem-1;
    return ptr[0];
}

Alternatively, you can override the new and delete operators in a similar manner.

How to set-up a favicon?

Try put this in the head of the document: <link rel="shortcut icon" type="image/x-icon" href="/favicon.ico"/>

iPad browser WIDTH & HEIGHT standard

The pixel width and height of your page will depend on orientation as well as the meta viewport tag, if specified. Here are the results of running jquery's $(window).width() and $(window).height() on iPad 1 browser.

When page has no meta viewport tag:

  • Portrait: 980x1208
  • Landscape: 980x661

When page has either of these two meta tags:

<meta name="viewport" content="initial-scale=1,user-scalable=no,maximum-scale=1,width=device-width">

<meta name="viewport" content="initial-scale=1,user-scalable=no,maximum-scale=1">

  • Portrait: 768x946
  • Landscape: 1024x690

With <meta name="viewport" content="width=device-width">:

  • Portrait: 768x946
  • Landscape: 768x518

With <meta name="viewport" content="height=device-height">:

  • Portrait: 980x1024
  • Landscape: 980x1024

With <meta name="viewport" content="height=device-height,width=device-width">:

  • Portrait: 768x1024
  • Landscape: 768x1024

With <meta name="viewport" content="initial-scale=1,user-scalable=no,maximum-scale=1,width=device-width,height=device-height">

  • Portrait: 768x1024
  • Landscape: 1024x1024

With <meta name="viewport" content="initial-scale=1,user-scalable=no,maximum-scale=1,height=device-height">

  • Portrait: 831x1024
  • Landscape: 1520x1024

Difference between using gradlew and gradle

The difference lies in the fact that ./gradlew indicates you are using a gradle wrapper. The wrapper is generally part of a project and it facilitates installation of gradle. If you were using gradle without the wrapper you would have to manually install it - for example, on a mac brew install gradle and then invoke gradle using the gradle command. In both cases you are using gradle, but the former is more convenient and ensures version consistency across different machines.

Each Wrapper is tied to a specific version of Gradle, so when you first run one of the commands above for a given Gradle version, it will download the corresponding Gradle distribution and use it to execute the build.

Not only does this mean that you don’t have to manually install Gradle yourself, but you are also sure to use the version of Gradle that the build is designed for. This makes your historical builds more reliable

Read more here - https://docs.gradle.org/current/userguide/gradle_wrapper.html

Also, Udacity has a neat, high level video explaining the concept of the gradle wrapper - https://www.youtube.com/watch?v=1aA949H-shk

Shortcut for echo "<pre>";print_r($myarray);echo "</pre>";

I just add function pr() to the global scope of my project. For example, you can define the following function to global.inc (if you have) which will be included into your index.php of your site. Or you can directly define this function at the top of index.php of root directory.

   function pr($obj)
   {
      echo "<pre>";
      print_r ($obj);
      echo "</pre>";
   }

Catch error if iframe src fails to load . Error :-"Refused to display 'http://www.google.co.in/' in a frame.."

I think that you can bind the load event of the iframe, the event fires when the iframe content is fully loaded.

At the same time you can start a setTimeout, if the iFrame is loaded clear the timeout alternatively let the timeout fire.

Code:

var iframeError;

function change() {
    var url = $("#addr").val();
    $("#browse").attr("src", url);
    iframeError = setTimeout(error, 5000);
}

function load(e) {
    alert(e);
}

function error() {
    alert('error');
}

$(document).ready(function () {
    $('#browse').on('load', (function () {
        load('ok');
        clearTimeout(iframeError);
    }));

});

Demo: http://jsfiddle.net/IrvinDominin/QXc6P/

Second problem

It is because you miss the parens in the inline function call; try change this:

<iframe id="browse" style="width:100%;height:100%" onload="load" onerror="error"></iframe>

into this:

<iframe id="browse" style="width:100%;height:100%" onload="load('Done func');" onerror="error('failed function');"></iframe>

Demo: http://jsfiddle.net/IrvinDominin/ALBXR/4/

Install a module using pip for specific python version

Python 2

sudo pip2 install johnbonjovi  

Python 3

sudo pip3 install johnbonjovi

Anaconda-Navigator - Ubuntu16.04

Simply create a new text document called "anaconda-navigator.desktop" in your home directory by the terminal command:

gedit anaconda-navigator.desktop

Then enter the following in your text document:

#!/usr/bin/env xdg-open
[Desktop Entry]
Name=Anaconda
Version=2.0
Type=Application
Exec=/path/to/anaconda-navigator
Icon=/path/to/selected/icon
Comment=Open Anaconda Navigator
Terminal=false

Save the file, then move it to your local applications folder:

mv anaconda-navigator.desktop ~/.local/share/applications/

Once this is done, you will be able to search for "Anaconda" on your applications screen, right click, and add to favorites. This way you don't have to go through the terminal every time!

Finished Product

How do I add a simple onClick event handler to a canvas element?

Alex Answer is pretty neat but when using context rotate it can be hard to trace x,y coordinates, so I have made a Demo showing how to keep track of that.

Basically I am using this function & giving it the angle & the amount of distance traveled in that angel before drawing object.

function rotCor(angle, length){
    var cos = Math.cos(angle);
    var sin = Math.sin(angle);

    var newx = length*cos;
    var newy = length*sin;

    return {
        x : newx,
        y : newy
    };
}

How does Java resolve a relative path in new File()?

There is a concept of a working directory.
This directory is represented by a . (dot).
In relative paths, everything else is relative to it.

Simply put the . (the working directory) is where you run your program.
In some cases the working directory can be changed but in general this is
what the dot represents. I think this is C:\JavaForTesters\ in your case.

So test\..\test.txt means: the sub-directory test
in my working directory, then one level up, then the
file test.txt. This is basically the same as just test.txt.

For more details check here.

http://docs.oracle.com/javase/7/docs/api/java/io/File.html

http://docs.oracle.com/javase/tutorial/essential/io/pathOps.html

Difference between "or" and || in Ruby?

The way I use these operators:

||, && are for boolean logic. or, and are for control flow. E.g.

do_smth if may_be || may_be -- we evaluate the condition here

do_smth or do_smth_else -- we define the workflow, which is equivalent to do_smth_else unless do_smth

to give a simple example:

> puts "a" && "b"
b

> puts 'a' and 'b'
a

A well-known idiom in Rails is render and return. It's a shortcut for saying return if render, while render && return won't work. See "Avoiding Double Render Errors" in the Rails documentation for more information.

Set default heap size in Windows

Try setting a Windows System Environment variable called _JAVA_OPTIONS with the heap size you want. Java should be able to find it and act accordingly.

HttpRequest maximum allowable size in tomcat?

Although other answers include some of the following information, this is the absolute minimum that needs to be changed on EC2 instances, specifically regarding deployment of large WAR files, and is the least likely to cause issues during future updates. I've been running into these limits about every other year due to the ever-increasing size of the Jenkins WAR file (now ~72MB).

More specifically, this answer is applicable if you encounter a variant of the following error in catalina.out:

SEVERE [https-jsse-nio-8443-exec-17] org.apache.catalina.core.ApplicationContext.log HTMLManager:
FAIL - Deploy Upload Failed, Exception:
[org.apache.tomcat.util.http.fileupload.FileUploadBase$SizeLimitExceededException:
the request was rejected because its size (75333656) exceeds the configured maximum (52428800)]

On Amazon EC2 Linux instances, the only file that needs to be modified from the default installation of Tomcat (sudo yum install tomcat8) is:

/usr/share/tomcat8/webapps/manager/WEB-INF/web.xml

By default, the maximum upload size is exactly 50MB:

<multipart-config>
  <!-- 50MB max -->
  <max-file-size>52428800</max-file-size>
  <max-request-size>52428800</max-request-size>
  <file-size-threshold>0</file-size-threshold>
</multipart-config>

There are only two values that need to be modified (max-file-size and max-request-size):

<multipart-config>
  <!-- 100MB max -->
  <max-file-size>104857600</max-file-size>
  <max-request-size>104857600</max-request-size>
  <file-size-threshold>0</file-size-threshold>
</multipart-config>

When Tomcat is upgraded on these instances, the new version of the manager web.xml will be placed in web.xml.rpmnew, so any modifications to the original file will not be overwritten during future updates.

How to convert an array to a string in PHP?

I would turn it into CSV form, like so:

$string_version = implode(',', $original_array)

You can turn it back by doing:

$destination_array = explode(',', $string_version)

what's data-reactid attribute in html?

data attributes are commonly used for a variety of interactions. Typically via javascript. They do not affect anything regarding site behavior and stand as a convenient method to pass data for whatever purpose needed. Here is an article that may clear things up:

http://ejohn.org/blog/html-5-data-attributes/

You can create a data attribute by prefixing data- to any standard attribute safe string (alphanumeric with no spaces or special characters). For example, data-id or in this case data-reactid

Gradle Sync failed could not find constraint-layout:1.0.0-alpha2

gradle com.android.tools.build:gradle:2.2.0-alpha6

constraint layout dependency com.android.support.constraint:constraint-layout:1.0.0-alpha4

works for me

Selecting only numeric columns from a data frame

The dplyr package's select_if() function is an elegant solution:

library("dplyr")
select_if(x, is.numeric)

Resetting a multi-stage form with jQuery

this worked for me , pyrotex answer didn' reset select fields, took his, here' my edit:

// Use a whitelist of fields to minimize unintended side effects.
$(':text, :password, :file', '#myFormId').val('');  
// De-select any checkboxes, radios and drop-down menus
$(':input,select option', '#myFormId').removeAttr('checked').removeAttr('selected');
//this is for selecting the first entry of the select
$('select option:first', '#myFormId').attr('selected',true);

How to call a parent class function from derived class function?

I'll take the risk of stating the obvious: You call the function, if it's defined in the base class it's automatically available in the derived class (unless it's private).

If there is a function with the same signature in the derived class you can disambiguate it by adding the base class's name followed by two colons base_class::foo(...). You should note that unlike Java and C#, C++ does not have a keyword for "the base class" (super or base) since C++ supports multiple inheritance which may lead to ambiguity.

class left {
public:
    void foo();
};

class right {
public:
    void foo();
};

class bottom : public left, public right {
public:
    void foo()
    {
        //base::foo();// ambiguous
        left::foo();
        right::foo();

        // and when foo() is not called for 'this':
        bottom b;
        b.left::foo();  // calls b.foo() from 'left'
        b.right::foo();  // call b.foo() from 'right'
    }
};

Incidentally, you can't derive directly from the same class twice since there will be no way to refer to one of the base classes over the other.

class bottom : public left, public left { // Illegal
};

SQLite DateTime comparison

The following is working fine for me using SQLite:

SELECT * 
    FROM ingresosgastos 
    WHERE fecharegistro BETWEEN "2010-01-01" AND "2013-01-01"

How can I get the active screen dimensions?

This debugging code should do the trick well:

You can explore the properties of the Screen Class

Put all displays in an array or list using Screen.AllScreens then capture the index of the current display and its properties.

enter image description here

C# (Converted from VB by Telerik - Please double check)

        {
    List<Screen> arrAvailableDisplays = new List<Screen>();
    List<string> arrDisplayNames = new List<string>();

    foreach (Screen Display in Screen.AllScreens)
    {
        arrAvailableDisplays.Add(Display);
        arrDisplayNames.Add(Display.DeviceName);
    }

    Screen scrCurrentDisplayInfo = Screen.FromControl(this);
    string strDeviceName = Screen.FromControl(this).DeviceName;
    int idxDevice = arrDisplayNames.IndexOf(strDeviceName);

    MessageBox.Show(this, "Number of Displays Found: " + arrAvailableDisplays.Count.ToString() + Constants.vbCrLf + "ID: " + idxDevice.ToString() + Constants.vbCrLf + "Device Name: " + scrCurrentDisplayInfo.DeviceName.ToString + Constants.vbCrLf + "Primary: " + scrCurrentDisplayInfo.Primary.ToString + Constants.vbCrLf + "Bounds: " + scrCurrentDisplayInfo.Bounds.ToString + Constants.vbCrLf + "Working Area: " + scrCurrentDisplayInfo.WorkingArea.ToString + Constants.vbCrLf + "Bits per Pixel: " + scrCurrentDisplayInfo.BitsPerPixel.ToString + Constants.vbCrLf + "Width: " + scrCurrentDisplayInfo.Bounds.Width.ToString + Constants.vbCrLf + "Height: " + scrCurrentDisplayInfo.Bounds.Height.ToString + Constants.vbCrLf + "Work Area Width: " + scrCurrentDisplayInfo.WorkingArea.Width.ToString + Constants.vbCrLf + "Work Area Height: " + scrCurrentDisplayInfo.WorkingArea.Height.ToString, "Current Info for Display '" + scrCurrentDisplayInfo.DeviceName.ToString + "' - ID: " + idxDevice.ToString(), MessageBoxButtons.OK, MessageBoxIcon.Information);
}

VB (Original code)

 Dim arrAvailableDisplays As New List(Of Screen)()
    Dim arrDisplayNames As New List(Of String)()

    For Each Display As Screen In Screen.AllScreens
        arrAvailableDisplays.Add(Display)
        arrDisplayNames.Add(Display.DeviceName)
    Next

    Dim scrCurrentDisplayInfo As Screen = Screen.FromControl(Me)
    Dim strDeviceName As String = Screen.FromControl(Me).DeviceName
    Dim idxDevice As Integer = arrDisplayNames.IndexOf(strDeviceName)

    MessageBox.Show(Me,
                    "Number of Displays Found: " + arrAvailableDisplays.Count.ToString & vbCrLf &
                    "ID: " & idxDevice.ToString + vbCrLf &
                    "Device Name: " & scrCurrentDisplayInfo.DeviceName.ToString + vbCrLf &
                    "Primary: " & scrCurrentDisplayInfo.Primary.ToString + vbCrLf &
                    "Bounds: " & scrCurrentDisplayInfo.Bounds.ToString + vbCrLf &
                    "Working Area: " & scrCurrentDisplayInfo.WorkingArea.ToString + vbCrLf &
                    "Bits per Pixel: " & scrCurrentDisplayInfo.BitsPerPixel.ToString + vbCrLf &
                    "Width: " & scrCurrentDisplayInfo.Bounds.Width.ToString + vbCrLf &
                    "Height: " & scrCurrentDisplayInfo.Bounds.Height.ToString + vbCrLf &
                    "Work Area Width: " & scrCurrentDisplayInfo.WorkingArea.Width.ToString + vbCrLf &
                    "Work Area Height: " & scrCurrentDisplayInfo.WorkingArea.Height.ToString,
                    "Current Info for Display '" & scrCurrentDisplayInfo.DeviceName.ToString & "' - ID: " & idxDevice.ToString, MessageBoxButtons.OK, MessageBoxIcon.Information)

Screens List

Difference between webdriver.Dispose(), .Close() and .Quit()

My understanding is driver.close(); will close the current browser, and driver.quit(); will terminate all the browser that.

Oracle's default date format is YYYY-MM-DD, WHY?

It's never wise to rely on defaults being set to a particular value, IMHO, whether it's for date formats, currency formats, optimiser modes or whatever. You should always set the value of date format that you need, in the server, the client, or the application.

In particular, never rely on defaults when converting date or numeric data types for display purposes, because a single change to the database can break your application. Always use an explicit conversion format. For years I worked on Oracle systems where the out of the box default date display format was MM/DD/RR, which drove me nuts but at least forced me to always use an explicit conversion.

How to close the current fragment by using Button like the back button?

If you need to handle the action more specifically with the back button you can use the following method:

view.setFocusableInTouchMode(true);
view.requestFocus();
view.setOnKeyListener(new View.OnKeyListener() {
    @Override
    public boolean onKey(View v, int keyCode, KeyEvent event) {
        if( keyCode == KeyEvent.KEYCODE_BACK )
        {
            onCloseFragment();
            return true;
        } else {
            return false;
        }
    }
});

Using import fs from 'fs'

For default exports you should use:

import * as fs from 'fs';

Or in case the module has named exports:

import {fs} from 'fs';

Example:

//module1.js

export function function1() {
  console.log('f1')
}

export function function2() {
  console.log('f2')
}

export default function1;

And then:

import defaultExport, { function1, function2 } from './module1'

defaultExport();  // This calls function1
function1();
function2();

Additionally, you should use Webpack or something similar to be able to use ES6 import

Receiving "fatal: Not a git repository" when attempting to remote add a Git repo

In my case the file .git/HEAD was corrupted (contained only dots). So I edited it and replaced its content with:

ref: refs/heads/master

and it started working again.

How to escape a JSON string to have it in a URL?

I was looking to do the same thing. problem for me was my url was getting way too long. I found a solution today using Bruno Jouhier's jsUrl.js library.

I haven't tested it very thoroughly yet. However, here is an example showing character lengths of the string output after encoding the same large object using 3 different methods:

  • 2651 characters using jQuery.param
  • 1691 characters using JSON.stringify + encodeURIComponent
  • 821 characters using JSURL.stringify

clearly JSURL has the most optimized format for urlEncoding a js object.

the thread at https://groups.google.com/forum/?fromgroups=#!topic/nodejs/ivdZuGCF86Q shows benchmarks for encoding and parsing.

Note: After testing, it looks like jsurl.js library uses ECMAScript 5 functions such as Object.keys, Array.map, and Array.filter. Therefore, it will only work on modern browsers (no ie 8 and under). However, are polyfills for these functions that would make it compatible with more browsers.

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).

Where should I put <script> tags in HTML markup?

If you are using JQuery then put the javascript wherever you find it best and use $(document).ready() to ensure that things are loaded properly before executing any functions.

On a side note: I like all my script tags in the <head> section as that seems to be the cleanest place.

How to loop over directories in Linux?

The technique I use most often is find | xargs. For example, if you want to make every file in this directory and all of its subdirectories world-readable, you can do:

find . -type f -print0 | xargs -0 chmod go+r
find . -type d -print0 | xargs -0 chmod go+rx

The -print0 option terminates with a NULL character instead of a space. The -0 option splits its input the same way. So this is the combination to use on files with spaces.

You can picture this chain of commands as taking every line output by find and sticking it on the end of a chmod command.

If the command you want to run as its argument in the middle instead of on the end, you have to be a bit creative. For instance, I needed to change into every subdirectory and run the command latemk -c. So I used (from Wikipedia):

find . -type d -depth 1 -print0 | \
    xargs -0 sh -c 'for dir; do pushd "$dir" && latexmk -c && popd; done' fnord

This has the effect of for dir $(subdirs); do stuff; done, but is safe for directories with spaces in their names. Also, the separate calls to stuff are made in the same shell, which is why in my command we have to return back to the current directory with popd.

How can I convert IPV6 address to IPV4 address?

The IPAddress Java library can accomplish what you are describing here.

IPv6 addresses are 16 bytes. Using that library, if you are starting with a 16-byte array you can construct the IPv6 address object:

IPv6Address addr = new IPv6Address(bytes); //bytes is byte[16]

From there you can check if the address is IPv4 mapped, IPv4 compatible, IPv4 translated, and so on (there are many possible ways IPv6 represents IPv4 addresses). In most cases, if an IPv6 address represents an IPv4 address, the ipv4 address is in the lower 4 bytes, and so you can get the derived IPv4 address as follows. Afterwards, you can convert back to bytes, which will be just 4 bytes for IPv4.

    if(addr.isIPv4Compatible() || addr.isIPv4Mapped()) {
        IPv4Address derivedIpv4Address = addr.getEmbeddedIPv4Address();
        byte ipv4Bytes[] = derivedIpv4Address.getBytes();
        ...
     }

The javadoc is available at the link.

How to concatenate two numbers in javascript?

// enter code here
var a = 9821099923;
var b = 91;
alert ("" + b + a); 
// after concating , result is 919821099923 but its is now converted into string  

console.log(Number.isInteger("" + b + a))  // false

// you have to do something like this

var c= parseInt("" + b + a)
console.log(c); // 919821099923
console.log(Number.isInteger(c)) // true

Should CSS always preceed Javascript?

Here is a SUMMARY of all the major answers above (or maybe below later :)

For modern browsers, put css wherever you like it. They would analyze your html file (which they call speculative parsing) and start downloading css in parallel with html parsing.

For old browsers keep putting css on top (if you don't want to show a naked but interactive page first).

For all browsers, put javascript as farther down on the page as possible, since it will halt parsing of your html. Preferably, download it asynchronously (i.e., ajax call)

There are also, some experimental results for a particular case which claims putting javascript first (as opposed to traditional wisdom of putting CSS first) gives better performance but there is no logical reasoning given for it, and lacks validation regarding widespread applicability, so you can ignore it for now.

So, to answer the question: Yes. The recommendation to include the CSS before JS is invalid for the modern browsers. Put CSS wherever you like, and put JS towards the end, as possible.

How to get input text length and validate user in javascript

JavaScript validation is not secure as anybody can change what your script does in the browser. Using it for enhancing the visual experience is ok though.

var textBox = document.getElementById("myTextBox");
var textLength = textBox.value.length;
if(textLength > 5)
{
    //red
    textBox.style.backgroundColor = "#FF0000";
}
else
{
    //green
    textBox.style.backgroundColor = "#00FF00";
}

"Series objects are mutable and cannot be hashed" error

gene_name = no_headers.iloc[1:,[1]]

This creates a DataFrame because you passed a list of columns (single, but still a list). When you later do this:

gene_name[x]

you now have a Series object with a single value. You can't hash the Series.

The solution is to create Series from the start.

gene_type = no_headers.iloc[1:,0]
gene_name = no_headers.iloc[1:,1]
disease_name = no_headers.iloc[1:,2]

Also, where you have orph_dict[gene_name[x]] =+ 1, I'm guessing that's a typo and you really mean orph_dict[gene_name[x]] += 1 to increment the counter.

How to write a PHP ternary operator

You wouldn’t: it’s messy and hard to read.

You’re looking for the switch statement in the first case. The second is fine as it is but still could be converted for consistency

Ternary statements are much more suited to boolean values and alternating logic.

How to prevent a browser from storing passwords

< input type="password" style='pointer-event: none' onInput= (e) => handleInput(e) />
function handleInput(e) {
  e.preventDefault();
  e.stopPropagation();
  e.target.setAttribute('readonly', true);
  setTimeout(() => {
    e.target.focus();
    e.target.removeAttribute('readonly');
  });
}

What does the "static" modifier after "import" mean?

Say you have static fields and methods inside a class called MyClass inside a package called myPackage and you want to access them directly by typing myStaticField or myStaticMethod without typing each time MyClass.myStaticField or MyClass.myStaticMethod.

Note : you need to do an import myPackage.MyClass or myPackage.* for accessing the other resources

Error : Index was outside the bounds of the array.

//if i input 9 it should go to 8?

You still have to work with the elements of the array. You will count 8 elements when looping through the array, but they are still going to be array(0) - array(7).

Function to convert timestamp to human date in javascript

formatDate is the function you can call it and pass the date you want to format to dd/mm/yyyy

_x000D_
_x000D_
var unformatedDate = new Date("2017-08-10 18:30:00");_x000D_
 _x000D_
$("#hello").append(formatDate(unformatedDate));_x000D_
function formatDate(nowDate) {_x000D_
 return nowDate.getDate() +"/"+ (nowDate.getMonth() + 1) + '/'+ nowDate.getFullYear();_x000D_
}
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<div id="hello">_x000D_
_x000D_
_x000D_
</div>
_x000D_
_x000D_
_x000D_

Android ImageView Animation

Use a RotateAnimation, setting the pivot point to the centre of your image.

RotateAnimation anim = new RotateAnimation(0f, 350f, 15f, 15f);
anim.setInterpolator(new LinearInterpolator());
anim.setRepeatCount(Animation.INFINITE);
anim.setDuration(700);

// Start animating the image
final ImageView splash = (ImageView) findViewById(R.id.splash);
splash.startAnimation(anim);

// Later.. stop the animation
splash.setAnimation(null);

Select current date by default in ASP.Net Calendar control

I was trying to make the calendar selects a date by default and highlights it for the user. However, i tried using all the options above but i only managed to set the calendar's selected date.

protected void Page_Load(object sender, EventArgs e)
    Calendar1.SelectedDate = DateTime.Today;
}

the previous code did NOT highlight the selection, although it set the SelectedDate to today.

However, to select and highlight the following code will work properly.

protected void Page_Load(object sender, EventArgs e)
{
    DateTime today = DateTime.Today;
    Calendar1.TodaysDate = today;
    Calendar1.SelectedDate = Calendar1.TodaysDate;
}

check this link: http://msdn.microsoft.com/en-us/library/8k0f6h1h(v=VS.85).aspx

Get first key in a (possibly) associative array?

You can play with your array

$daysArray = array('Monday', 'Tuesday', 'Sunday');
$day = current($transport); // $day = 'Monday';
$day = next($transport);    // $day = 'Tuesday';
$day = current($transport); // $day = 'Tuesday';
$day = prev($transport);    // $day = 'Monday';
$day = end($transport);     // $day = 'Sunday';
$day = current($transport); // $day = 'Sunday';

To get the first element of array you can use current and for last element you can use end

Edit

Just for the sake for not getting any more down votes for the answer you can convert you key to value using array_keys and use as shown above.

How do I force "git pull" to overwrite local files?

I used this command to get rid of the local files preventing me from doing a pull/merge. But be careful! Run git merge … first to see whether there are only those files you really want to remove.

git merge origin/master 2>&1 >/dev/null | grep ^[[:space:]] | sed s/^[[:space:]]//g | xargs -L1 rm
  • git merge lists among other things all those files. They are prepended by some white-space.
  • 2>&1 >/dev/null redirects the error output to the standard one so it is picked up by grep.
  • grep ^[[:space:]] filters only the lines with file names.
  • sed s/^[[:space:]]//g trims the white-space from the beginning.
  • xargs -L1 rm calls rm on each of those files, deleting them.

Handle with care: Whatever git merge outputs, the rm will be called for every line beginning with a white-space.

How can I disable all views inside the layout?

Details

  • Android studio 3.1.4
  • Kotlin 1.2.70
  • checked in minSdkVersion 19

Solution

fun View.forEachChildView(closure: (View) -> Unit) {
    closure(this)
    val groupView = this as? ViewGroup ?: return
    val size = groupView.childCount - 1
    for (i in 0..size) {
        groupView.getChildAt(i).forEachChildView(closure)
    }
}

Usage

val layout = LinearLayout(context!!)
layout.forEachChildView {  it.isEnabled = false  }

val view = View(context!!)
view.forEachChildView {  it.isEnabled = false  }

val fragment = Fragment.instantiate(context, "fragment_id")
fragment.view?.forEachChildView {  it.isEnabled = false  }

Delete rows containing specific strings in R

Actually I would use:

df[ grep("REVERSE", df$Name, invert = TRUE) , ]

This will avoid deleting all of the records if the desired search word is not contained in any of the rows.

Are vectors passed to functions by value or by reference in C++

when we pass vector by value in a function as an argument,it simply creates the copy of vector and no any effect happens on the vector which is defined in main function when we call that particular function. while when we pass vector by reference whatever is written in that particular function, every action will going to perform on the vector which is defined in main or other function when we call that particular function.

How can I select all options of multi-select select box on click?

Working Demo

$('#select_all').click( function() {
    $('select#countries > option').prop('selected', 'selected');
});

If you use jQuery older than 1.6:

$('#select_all').click( function() {
    $('select#countries > option').attr('selected', 'selected');
});

Ignore fields from Java object dynamically while sending as JSON from Spring MVC

I've solved using only @JsonIgnore like @kryger has suggested. So your getter will become:

@JsonIgnore
public String getEncryptedPwd() {
    return this.encryptedPwd;
}

You can set @JsonIgnore of course on field, setter or getter like described here.

And, if you want to protect encrypted password only on serialization side (e.g. when you need to login your users), add this @JsonProperty annotation to your field:

@JsonProperty(access = Access.WRITE_ONLY)
private String encryptedPwd;

More info here.

How to get current domain name in ASP.NET

Here is a screenshot of Request.RequestUri and all its properties for everyone's reference.

enter image description here

Should Gemfile.lock be included in .gitignore?

No Gemfile.lock means:

  • new contributors cannot run tests because weird things fail, so they won't contribute or get failing PRs ... bad first experience.
  • you cannot go back to a x year old project and fix a bug without having to update/rewrite the project if you lost your local Gemfile.lock

-> Always check in Gemfile.lock, make travis delete it if you want to be extra thorough https://grosser.it/2015/08/14/check-in-your-gemfile-lock/

Is there a label/goto in Python?

No, Python does not support labels and goto, if that is what you're after. It's a (highly) structured programming language.

VSCode regex find & replace submatch math?

Another simple example:

Search: style="(.+?)"
Replace: css={css`$1`}

Useful for converting HTML to JSX with emotion/css!

Break string into list of characters in Python

python >= 3.5

Version 3.5 onwards allows the use of PEP 448 - Extended Unpacking Generalizations:

>>> string = 'hello'
>>> [*string]
['h', 'e', 'l', 'l', 'o']

This is a specification of the language syntax, so it is faster than calling list:

>>> from timeit import timeit
>>> timeit("list('hello')")
0.3042821969866054
>>> timeit("[*'hello']")
0.1582647830073256

How to select and change value of table cell with jQuery?

I wanted to change the column value in a specific row. Thanks to above answers and after some serching able to come up with below,

var dataTable = $("#yourtableid");
var rowNumber = 0;  
var columnNumber= 2;   
dataTable[0].rows[rowNumber].cells[columnNumber].innerHTML = 'New Content';

`IF` statement with 3 possible answers each based on 3 different ranges

Your formula should be of the form =IF(X2 >= 85,0.559,IF(X2 >= 80,0.327,IF(X2 >=75,0.255,0))). This simulates the ELSE-IF operand Excel lacks. Your formulas were using two conditions in each, but the second parameter of the IF formula is the value to use if the condition evaluates to true. You can't chain conditions in that manner.

How to declare and initialize a static const array as a class member?

// in foo.h
class Foo {
    static const unsigned char* Msg;
};

// in foo.cpp
static const unsigned char Foo_Msg_data[] = {0x00,0x01};
const unsigned char* Foo::Msg = Foo_Msg_data;

Is there a git-merge --dry-run option?

I use git log to see what has changed on a feature branch from master branch

git log does_this_branch..contain_this_branch_changes

e.g. - to see what commits are in a feature branch that has/not been merged to master:

git log master..feature_branch

Is there a way to remove the separator line from a UITableView?

You can do this with the UITableView property separatorStyle. Make sure the property is set to UITableViewCellSeparatorStyleNone and you're set.

Objective-C

self.tableView.separatorStyle = UITableViewCellSeparatorStyleNone;

In Swift (prior to 3)

tableView.separatorStyle = .None

In Swift 3/4/5

tableView.separatorStyle = .none

Forcing to download a file using PHP

To force download you may use Content-Type: application/force-download header, which is supported by most browsers:

function downloadFile($filePath)
{
    header("Content-type: application/octet-stream");
    header('Content-Disposition: attachment; filename="' . basename($filePath) . '"');
    header('Content-Length: ' . filesize($filePath));
    readfile($filePath);
}

A BETTER WAY

Downloading files this way is not the best idea especially for large files. PHP will require extra CPU / Memory to read and output file contents and when dealing with large files may reach time / memory limits.

A better way would be to use PHP to authenticate and grant access to a file, and actual file serving should be delegated to a web server using X-SENDFILE method (requires some web server configuration):

After configuring web server to handle X-SENDFILE, just replace readfile($filePath) with header('X-SENDFILE: ' . $filePath) and web server will take care of file serving, which will require less resources than using PHP readfile.

(For Nginx use X-Accel-Redirect header instead of X-SENDFILE)

Note: If you end up downloading empty files, it means you didn't configure your web server to handle X-SENDFILE header. Check the links above to see how to correctly configure your web server.

Why doesn't list have safe "get" method like dictionary?

Ultimately it probably doesn't have a safe .get method because a dict is an associative collection (values are associated with names) where it is inefficient to check if a key is present (and return its value) without throwing an exception, while it is super trivial to avoid exceptions accessing list elements (as the len method is very fast). The .get method allows you to query the value associated with a name, not directly access the 37th item in the dictionary (which would be more like what you're asking of your list).

Of course, you can easily implement this yourself:

def safe_list_get (l, idx, default):
  try:
    return l[idx]
  except IndexError:
    return default

You could even monkeypatch it onto the __builtins__.list constructor in __main__, but that would be a less pervasive change since most code doesn't use it. If you just wanted to use this with lists created by your own code you could simply subclass list and add the get method.

Find and copy files

for i in $(ls); do cp -r "$i" "$i"_dev; done;

What is the purpose of nameof?

The most common use case I can think of is when working with the INotifyPropertyChanged interface. (Basically everything related to WPF and bindings uses this interface)

Take a look at this example:

public class Model : INotifyPropertyChanged
{
    // From the INotifyPropertyChanged interface
    public event PropertyChangedEventHandler PropertyChanged;

    private string foo;
    public String Foo
    {
        get { return this.foo; }
        set
        {
            this.foo = value;
            // Old code:
            PropertyChanged(this, new PropertyChangedEventArgs("Foo"));

            // New Code:
            PropertyChanged(this, new PropertyChangedEventArgs(nameof(Foo)));           
        }
    }
}

As you can see in the old way we have to pass a string to indicate which property has changed. With nameof we can use the name of the property directly. This might not seem like a big deal. But image what happens when somebody changes the name of the property Foo. When using a string the binding will stop working, but the compiler will not warn you. When using nameof you get a compiler error that there is no property/argument with the name Foo.

Note that some frameworks use some reflection magic to get the name of the property, but now we have nameof this is no longer neccesary.

Disable a Button

The boolean value for NO in Swift is false.

button.isEnabled = false

should do it.

Here is the Swift documentation for UIControl's isEnabled property.

What .NET collection provides the fastest search

If you're using .Net 3.5, you can make cleaner code using:

foreach (Record item in LookupCollection.Intersect(LargeCollection))
{
  //dostuff
}

I don't have .Net 3.5 here and so this is untested. It relies on an extension method. Not that LookupCollection.Intersect(LargeCollection) is probably not the same as LargeCollection.Intersect(LookupCollection) ... the latter is probably much slower.

This assumes LookupCollection is a HashSet

Giving a border to an HTML table row, <tr>

You can use the box-shadow property on a tr element as a subtitute for a border. As a plus, any border-radius property on the same element will also apply to the box shadow.

box-shadow: 0px 0px 0px 1px rgb(0, 0, 0);

The number of method references in a .dex file cannot exceed 64k API 17

I got this error message because while coding my project auto update compile version in my build.gradle file :

android {
    ...
    buildToolsVersion "23.0.2"
    ...
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.4.0'
    compile 'com.android.support:design:23.4.0' }

Solve it by correcting the version:

android {
        ...
        buildToolsVersion "23.0.2"
        ...
    }

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.0.1'
    compile 'com.android.support:design:23.0.1'
}

Fiddler not capturing traffic from browsers

For it was betternet extension was causing issue. I think any kind of proxy extension installed on Chrome causing issue.

How to render an array of objects in React?

import React from 'react';

class RentalHome extends React.Component{
    constructor(){
        super();
        this.state = {
            rentals:[{
                _id: 1,
                title: "Nice Shahghouse Biryani",
                city: "Hyderabad",
                category: "condo",
                image: "http://via.placeholder.com/350x250",
                numOfRooms: 4,
                shared: true,
                description: "Very nice apartment in center of the city.",
                dailyPrice: 43
              },
              {
                _id: 2,
                title: "Modern apartment in center",
                city: "Bangalore",
                category: "apartment",
                image: "http://via.placeholder.com/350x250",
                numOfRooms: 1,
                shared: false,
                description: "Very nice apartment in center of the city.",
                dailyPrice: 11
              },
              {
                _id: 3,
                title: "Old house in nature",
                city: "Patna",
                category: "house",
                image: "http://via.placeholder.com/350x250",
                numOfRooms: 5,
                shared: true,
                description: "Very nice apartment in center of the city.",
                dailyPrice: 23
              }]
        }
    }
    render(){
        const {rentals} = this.state;
        return(
            <div className="card-list">
                <div className="container">
                    <h1 className="page-title">Your Home All Around the World</h1>
                    <div className="row">
                        {
                            rentals.map((rental)=>{
                                return(
                                    <div key={rental._id} className="col-md-3">
                                        <div className="card bwm-card">
                                        <img 
                                        className="card-img-top" 
                                        src={rental.image}
                                        alt={rental.title} />
                                        <div className="card-body">
                                        <h6 className="card-subtitle mb-0 text-muted">
                                            {rental.shared} {rental.category} {rental.city}
                                        </h6>
                                        <h5 className="card-title big-font">
                                            {rental.title}
                                        </h5>
                                        <p className="card-text">
                                            ${rental.dailyPrice} per Night &#183; Free Cancelation
                                        </p>
                                        </div>
                                        </div>
                                    </div>
                                )
                            })
                        }
                        
                    </div>
                </div>
            </div>
        )
    }
}

export default RentalHome;

How to loop through an array containing objects and access their properties

Array object iteration, using jQuery, (use the second parameter to print the string).

$.each(array, function(index, item) {
       console.log(index, item);
});

Passing enum or object through an intent (the best solution)

I like simple.

  • The Fred activity has two modes -- HAPPY and SAD.
  • Create a static IntentFactory that creates your Intent for you. Pass it the Mode you want.
  • The IntentFactory uses the name of the Mode class as the name of the extra.
  • The IntentFactory converts the Mode to a String using name()
  • Upon entry into onCreate use this info to convert back to a Mode.
  • You could use ordinal() and Mode.values() as well. I like strings because I can see them in the debugger.

    public class Fred extends Activity {
    
        public static enum Mode {
            HAPPY,
            SAD,
            ;
        }
    
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.betting);
            Intent intent = getIntent();
            Mode mode = Mode.valueOf(getIntent().getStringExtra(Mode.class.getName()));
            Toast.makeText(this, "mode="+mode.toString(), Toast.LENGTH_LONG).show();
        }
    
        public static Intent IntentFactory(Context context, Mode mode){
            Intent intent = new Intent();
            intent.setClass(context,Fred.class);
            intent.putExtra(Mode.class.getName(),mode.name());
    
            return intent;
        }
    }
    

Understanding the Gemfile.lock file

in regards to the exclamation mark I just found out it's on gems fetched via :git, e.g.

gem "foo", :git => "[email protected]:company/foo.git"

How to increase Maximum Upload size in cPanel?

The solution is to create the php.ini file under your root directory. If the site is the wordpress installation then create the php.ini under your/path/to/wordpress/wp-admin/php.ini and add the following line of codes

[PHP]
post_max_size=120M
upload_max_filesize=132M

PHP with MySQL 8.0+ error: The server requested authentication method unknown to the client

In my.cnf file check below 2 steps.

  • check this value -

    old_passwords=0;

    it should be 0.

  • check this also-

    [mysqld] default_authentication_plugin= mysql_native_password Another value to check is to make sure

    [mysqld] section should be like this.

What is the different between RESTful and RESTless

Here are summarized the key differences between RESTful and RESTless web services:

1. Protocol

  • RESTful services use REST architectural style,
  • RESTless services use SOAP protocol.

2. Business logic / Functionality

  • RESTful services use URL to expose business logic,
  • RESTless services use the service interface to expose business logic.

3. Security

  • RESTful inherits security from the underlying transport protocols,
  • RESTless defines its own security layer, thus it is considered as more secure.

4. Data format

  • RESTful supports various data formats such as HTML, JSON, text, etc,
  • RESTless supports XML format.

5. Flexibility

  • RESTful is easier and flexible,
  • RESTless is not as easy and flexible.

6. Bandwidth

  • RESTful services consume less bandwidth and resource,
  • RESTless services consume more bandwidth and resources.

Getting char from string at specified index

If s is your string than you could do it this way:

Mid(s, index, 1)

Edit based on comment below question.

It seems that you need a bit different approach which should be easier. Try in this way:

Dim character As String 'Integer if for numbers
's = ActiveDocument.Content.Text - we don't need it
character = Activedocument.Characters(index)

JavaScript OOP in NodeJS: how?

I suggest to use the inherits helper that comes with the standard util module: http://nodejs.org/api/util.html#util_util_inherits_constructor_superconstructor

There is an example of how to use it on the linked page.

Generating Fibonacci Sequence

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
        <title>fibonacci series</title>
        <script type="text/javascript">
                function generateseries(){
                    var fno = document.getElementById("firstno").value;
                    var sno = document.getElementById("secondno").value;
                    var a = parseInt(fno);
                    var result = new Array();
                    result[0] = a;
                    var b = ++fno;
                    var c = b;
                    while (b <= sno) {  
                    result.push(c);
                    document.getElementById("maindiv").innerHTML = "Fibonacci Series between "+fno+ " and " +sno+ " is " +result;
                        c = a + b;
                        a = b;
                        b = c;
                    }
                }
                function numeric(evt){
                    var theEvent = evt || window.event;
                    var key = theEvent.keyCode || theEvent.which;
                    key = String.fromCharCode(key);
                    var regex = /[0-9]|\./;
                    if (!regex.test(key)) {
                        theEvent.returnValue = false;
                        if (theEvent.preventDefault) 
                            theEvent.preventDefault();
                    }
                }

            </script>
        <h1 align="center">Fibonacci Series</h1>
    </head>
    <body>
        <div id="resultdiv" align="center">
        <input type="text" name="firstno" id="firstno" onkeypress="numeric(event)"><br>
        <input type="text" name="secondno" id="secondno" onkeypress="numeric(event)"><br>
        <input type="button" id="result" value="Result" onclick="generateseries();">
        <div id="maindiv"></div>
        </div>
    </body>
</html>

Usage of \b and \r in C

The characters are exactly as documented - \b equates to a character code of 0x08 and \r equates to 0x0d. The thing that varies is how your OS reacts to those characters. Back when displays were trying to emulate an old teletype those actions were standardized, but they are less useful in modern environments and compatibility is not guaranteed.

PHP multiline string with PHP

Use the show_source(); function of PHP. Check for more details in show_source. This is a better method I guess.

How do I fix 'Invalid character value for cast specification' on a date column in flat file?

In order to simulate the issue that you are facing, I created the following sample using SSIS 2008 R2 with SQL Server 2008 R2 backend. The example is based on what I gathered from your question. This example doesn't provide a solution but it might help you to identify where the problem could be in your case.

Created a simple CSV file with two columns namely order number and order date. As you had mentioned in your question, values of both the columns are qualified with double quotes (") and also the lines end with Line Feed (\n) with the date being the last column. The below screenshot was taken using Notepad++, which can display the special characters in a file. LF in the screenshot denotes Line Feed.

Orders file

Created a simple table named dbo.Destination in the SQL Server database to populate the CSV file data using SSIS package. Create script for the table is given below.

CREATE TABLE [dbo].[Destination](
    [OrderNumber] [varchar](50) NULL,
    [OrderDate] [date] NULL
) ON [PRIMARY]
GO

On the SSIS package, I created two connection managers. SQLServer was created using the OLE DB Connection to connect to the SQL Server database. FlatFile is a flat file connection manager.

Connections

Flat file connection manager was configured to read the CSV file and the settings are shown below. The red arrows indicate the changes made.

Provided a name to the flat file connection manager. Browsed to the location of the CSV file and selected the file path. Entered the double quote (") as the text qualifier. Changed the Header row delimiter from {CR}{LF} to {LF}. This header row delimiter change also reflects on the Columns section.

Flat File General

No changes were made in the Columns section.

Flat File Columns

Changed the column name from Column0 to OrderNumber.

Advanced column OrderNumber

Changed the column name from Column1 to OrderDate and also changed the data type to date [DT_DATE]

Advanced column OrderDate

Preview of the data within the flat file connection manager looks good.

Data Preview

On the Control Flow tab of the SSIS package, placed a Data Flow Task.

Control Flow

Within the Data Flow Task, placed a Flat File Source and an OLE DB Destination.

Data Flow Task

The Flat File Source was configured to read the CSV file data using the FlatFile connection manager. Below three screenshots show how the flat file source component was configured.

Flat File Source Connection Manager

Flat File Source Columns

Flat File Source Error Output

The OLE DB Destination component was configured to accept the data from Flat File Source and insert it into SQL Server database table named dbo.Destination. Below three screenshots show how the OLE DB Destination component was configured.

OLE DB Destination Connection Manager

OLE DB Destination Mappings

OLE DB Destination Error Output

Using the steps mentioned in the below 5 screenshots, I added a data viewer on the flow between the Flat File Source and OLE DB Destination.

Right click

Data Flow Path Editor New

Configure Data Viewer

Data Flow Path Editor Added

Data Viewer visible

Before running the package, I verified the initial data present in the table. It is currently empty because I created this using the script provided at the beginning of this post.

Empty Table

Executed the package and the package execution temporarily paused to display the data flowing from Flat File Source to OLE DB Destination in the data viewer. I clicked on the run button to proceed with the execution.

Data Viewer Pause

The package executed successfully.

Successful execution

Flat file source data was inserted successfully into the table dbo.Destination.

Data in table

Here is the layout of the table dbo.Destination. As you can see, the field OrderDate is of data type date and the package still continued to insert the data correctly.

Destination layout

This post even though is not a solution. Hopefully helps you to find out where the problem could be in your scenario.

Tests not running in Test Explorer

Try removing the [Ignore] attribute from above the test method.

Create a new txt file using VB.NET

open C:\myfile.txt for append as #1
write #1, text1.text, text2.text
close()

This is the code I use in Visual Basic 6.0. It helps me to create a txt file on my drive, write two pieces of data into it, and then close the file... Give it a try...

What is the best open XML parser for C++?

pugixml - Light-weight, simple and fast XML parser for C++ Very small (comparable to RapidXML), very fast (comparable to RapidXML), very easy to use (better than RapidXML).

How to generate all permutations of a list?

def permuteArray (arr):

    arraySize = len(arr)

    permutedList = []

    if arraySize == 1:
        return [arr]

    i = 0

    for item in arr:

        for elem in permuteArray(arr[:i] + arr[i + 1:]):
            permutedList.append([item] + elem)

        i = i + 1    

    return permutedList

I intended to not exhaust every possibility in a new line to make it somewhat unique.

How to set the Default Page in ASP.NET?

If using IIS 7 or IIS 7.5 you can use

<system.webServer>
    <defaultDocument>
        <files>
            <clear />
            <add value="CreateThing.aspx" />
        </files>
    </defaultDocument>
</system.webServer>

https://docs.microsoft.com/en-us/iis/configuration/system.webServer/defaultDocument/

How can I find out a file's MIME type (Content-Type)?

file version < 5 : file -i -b /path/to/file
file version >=5 : file --mime-type -b /path/to/file

Best way to update an element in a generic List

If the list is sorted (as happens to be in the example) a binary search on index certainly works.

    public static Dog Find(List<Dog> AllDogs, string Id)
    {
        int p = 0;
        int n = AllDogs.Count;
        while (true)
        {
            int m = (n + p) / 2;
            Dog d = AllDogs[m];
            int r = string.Compare(Id, d.Id);
            if (r == 0)
                return d;
            if (m == p)
                return null;
            if (r < 0)
                n = m;
            if (r > 0)
                p = m;
        }
    }

Not sure what the LINQ version of this would be.

Regex: ignore case sensitivity

The i flag is normally used for case insensitivity. You don't give a language here, but it'll probably be something like /G[ab].*/i or /(?i)G[ab].*/.

Java: get greatest common divisor

/*
import scanner and instantiate scanner class;
declare your method with two parameters
declare a third variable;
set condition;
swap the parameter values if condition is met;
set second conditon based on result of first condition;
divide and assign remainder to the third variable;
swap the result;
in the main method, allow for user input;
Call the method;

*/
public class gcf {
    public static void main (String[]args){//start of main method
        Scanner input = new Scanner (System.in);//allow for user input
        System.out.println("Please enter the first integer: ");//prompt
        int a = input.nextInt();//initial user input
        System.out.println("Please enter a second interger: ");//prompt
        int b = input.nextInt();//second user input


       Divide(a,b);//call method
    }
   public static void Divide(int a, int b) {//start of your method

    int temp;
    // making a greater than b
    if (b > a) {
         temp = a;
         a = b;
         b = temp;
    }

    while (b !=0) {
        // gcd of b and a%b
        temp = a%b;
        // always make a greater than b
        a =b;
        b =temp;

    }
    System.out.println(a);//print to console
  }
}

How to combine two or more querysets in a Django view?

DATE_FIELD_MAPPING = {
    Model1: 'date',
    Model2: 'pubdate',
}

def my_key_func(obj):
    return getattr(obj, DATE_FIELD_MAPPING[type(obj)])

And then sorted(chain(Model1.objects.all(), Model2.objects.all()), key=my_key_func)

Quoted from https://groups.google.com/forum/#!topic/django-users/6wUNuJa4jVw. See Alex Gaynor

What version of JBoss I am running?

Just found another way to know the jboss version, so pointing out here:

In Linux/Windows use --version parameter along with Jboss executable to know the Jboss Version

eg:

[immo@g012 bin]$  ./run.sh --version
========================================================================

  JBoss Bootstrap Environment

  JBOSS_HOME: /programs/jboss4.2-AES2.3Cert

  JAVA: /programs/java/jdk1.7.0_09/bin/java

  JAVA_OPTS: -server -Xms128m -Xmx512m -Dsun.rmi.dgc.client.gcInterval=3600000 

  CLASSPATH: /programs/jboss4.2-AES2.3Cert/bin/run.jar:/programs/java/jdk1.7.0_09/lib/tools.jar

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

Listening for transport dt_socket at address: 8787
JBoss 4.0.4.GA (build: CVSTag=JBoss_4_0_4_GA date=200605151000)

Here JBoss 4.0.4.GA is the Jboss version

in windows this could be

run.bat --version

Also, in new versions of jboss the executable is standalone.sh / standalone.bat

How does origin/HEAD get set?

It is your setting as the owner of your local repo. Change it like this:

git remote set-head origin some_branch

And origin/HEAD will point to your branch instead of master. This would then apply to your repo only and not for others. By default, it will point to master, unless something else has been configured on the remote repo.

Manual entry for remote set-head provides some good information on this.

Edit: to emphasize: without you telling it to, the only way it would "move" would be a case like renaming the master branch, which I don't think is considered "organic". So, I would say organically it does not move.

Programmatically get the version number of a DLL

var versionAttrib = new AssemblyName(Assembly.GetExecutingAssembly().FullName);

proper way to sudo over ssh

Another way is to use the -t switch to ssh:

ssh -t user@server "sudo script"

See man ssh:

 -t      Force pseudo-tty allocation.  This can be used to execute arbi-
         trary screen-based programs on a remote machine, which can be
         very useful, e.g., when implementing menu services.  Multiple -t
         options force tty allocation, even if ssh has no local tty.

Regex - Does not contain certain Characters

^[^<>]+$

The caret in the character class ([^) means match anything but, so this means, beginning of string, then one or more of anything except < and >, then the end of the string.

How to disable EditText in Android

According to me...if you have already declared the edittext in the XML file and set the property in the XML file "android:enabled=false" and disable at runtime to it at that time in java file adding only 2 or 3 lines

  1. First create the object
  2. Declare EditText et1;
  3. Get by id

    et1 = (EditText) FindViewById(R.id.edittext1);
    et1.setEnabled(false);

You can do enable or disable to every control at run time by java file and design time by XML file.

What in the world are Spring beans?

In Spring, those objects that form the backbone of your application and that are managed by the Spring IoC container are referred to as beans. A bean is simply an object that is instantiated, assembled and otherwise managed by a Spring IoC container;

Understanding SQL Server LOCKS on SELECT queries

A SELECT in SQL Server will place a shared lock on a table row - and a second SELECT would also require a shared lock, and those are compatible with one another.

So no - one SELECT cannot block another SELECT.

What the WITH (NOLOCK) query hint is used for is to be able to read data that's in the process of being inserted (by another connection) and that hasn't been committed yet.

Without that query hint, a SELECT might be blocked reading a table by an ongoing INSERT (or UPDATE) statement that places an exclusive lock on rows (or possibly a whole table), until that operation's transaction has been committed (or rolled back).

Problem of the WITH (NOLOCK) hint is: you might be reading data rows that aren't going to be inserted at all, in the end (if the INSERT transaction is rolled back) - so your e.g. report might show data that's never really been committed to the database.

There's another query hint that might be useful - WITH (READPAST). This instructs the SELECT command to just skip any rows that it attempts to read and that are locked exclusively. The SELECT will not block, and it will not read any "dirty" un-committed data - but it might skip some rows, e.g. not show all your rows in the table.

How to update the constant height constraint of a UIView programmatically?

Select the height constraint from the Interface builder and take an outlet of it. So, when you want to change the height of the view you can use the below code.

yourHeightConstraintOutlet.constant = someValue
yourView.layoutIfNeeded()

Method updateConstraints() is an instance method of UIView. It is helpful when you are setting the constraints programmatically. It updates constraints for the view. For more detail click here.

Fatal error: Call to a member function prepare() on null

In ---- model: Add use Jenssegers\Mongodb\Eloquent\Model as Eloquent;

Change the class ----- extends Model to class ----- extends Eloquent

How to use Checkbox inside Select Option

You cannot place checkbox inside select element but you can get the same functionality by using HTML, CSS and JavaScript. Here is a possible working solution. The explanation follows.

enter image description here


Code:

_x000D_
_x000D_
var expanded = false;_x000D_
_x000D_
function showCheckboxes() {_x000D_
  var checkboxes = document.getElementById("checkboxes");_x000D_
  if (!expanded) {_x000D_
    checkboxes.style.display = "block";_x000D_
    expanded = true;_x000D_
  } else {_x000D_
    checkboxes.style.display = "none";_x000D_
    expanded = false;_x000D_
  }_x000D_
}
_x000D_
.multiselect {_x000D_
  width: 200px;_x000D_
}_x000D_
_x000D_
.selectBox {_x000D_
  position: relative;_x000D_
}_x000D_
_x000D_
.selectBox select {_x000D_
  width: 100%;_x000D_
  font-weight: bold;_x000D_
}_x000D_
_x000D_
.overSelect {_x000D_
  position: absolute;_x000D_
  left: 0;_x000D_
  right: 0;_x000D_
  top: 0;_x000D_
  bottom: 0;_x000D_
}_x000D_
_x000D_
#checkboxes {_x000D_
  display: none;_x000D_
  border: 1px #dadada solid;_x000D_
}_x000D_
_x000D_
#checkboxes label {_x000D_
  display: block;_x000D_
}_x000D_
_x000D_
#checkboxes label:hover {_x000D_
  background-color: #1e90ff;_x000D_
}
_x000D_
<form>_x000D_
  <div class="multiselect">_x000D_
    <div class="selectBox" onclick="showCheckboxes()">_x000D_
      <select>_x000D_
        <option>Select an option</option>_x000D_
      </select>_x000D_
      <div class="overSelect"></div>_x000D_
    </div>_x000D_
    <div id="checkboxes">_x000D_
      <label for="one">_x000D_
        <input type="checkbox" id="one" />First checkbox</label>_x000D_
      <label for="two">_x000D_
        <input type="checkbox" id="two" />Second checkbox</label>_x000D_
      <label for="three">_x000D_
        <input type="checkbox" id="three" />Third checkbox</label>_x000D_
    </div>_x000D_
  </div>_x000D_
</form>
_x000D_
_x000D_
_x000D_

Explanation:

At first we create a select element that shows text "Select an option", and empty element that covers (overlaps) the select element (<div class="overSelect">). We do not want the user to click on the select element - it would show an empty options. To overlap the element with other element we use CSS position property with value relative | absolute.

To add the functionality we specify a JavaScript function that is called when the user clicks on the div that contains our select element (<div class="selectBox" onclick="showCheckboxes()">).

We also create div that contains our checkboxes and style it using CSS. The above mentioned JavaScript function just changes <div id="checkboxes"> value of CSS display property from "none" to "block" and vice versa.

The solution was tested in the following browsers: Internet Explorer 10, Firefox 34, Chrome 39. The browser needs to have JavaScript enabled.


More information:

CSS positioning

How to overlay one div over another div

http://www.w3schools.com/css/css_positioning.asp

CSS display property

http://www.w3schools.com/cssref/pr_class_display.asp

Checking images for similarity with OpenCV

If for matching identical images ( same size/orientation )

// Compare two images by getting the L2 error (square-root of sum of squared error).
double getSimilarity( const Mat A, const Mat B ) {
if ( A.rows > 0 && A.rows == B.rows && A.cols > 0 && A.cols == B.cols ) {
    // Calculate the L2 relative error between images.
    double errorL2 = norm( A, B, CV_L2 );
    // Convert to a reasonable scale, since L2 error is summed across all pixels of the image.
    double similarity = errorL2 / (double)( A.rows * A.cols );
    return similarity;
}
else {
    //Images have a different size
    return 100000000.0;  // Return a bad value
}

Source

Why do I get "'property cannot be assigned" when sending an SMTP email?

 //Hope you find it useful, it contain too many things

    string smtpAddress = "smtp.xyz.com";
    int portNumber = 587;
    bool enableSSL = true;
    string m_userName = "[email protected]";
    string m_UserpassWord = "56436578";

    public void SendEmail(Customer _customers)
    {
        string emailID = [email protected];
        string userName = DemoUser;

        string emailFrom = "[email protected]";
        string password = "qwerty";
        string emailTo = emailID;

        // Here you can put subject of the mail
        string subject = "Registration";
        // Body of the mail
        string body = "<div style='border: medium solid grey; width: 500px; height: 266px;font-family: arial,sans-serif; font-size: 17px;'>";
        body += "<h3 style='background-color: blueviolet; margin-top:0px;'>Aspen Reporting Tool</h3>";
        body += "<br />";
        body += "Dear " + userName + ",";
        body += "<br />";
        body += "<p>";
        body += "Thank you for registering </p>";            
        body += "<p><a href='"+ sURL +"'>Click Here</a>To finalize the registration process</p>";
        body += " <br />";
        body += "Thanks,";
        body += "<br />";
        body += "<b>The Team</b>";
        body += "</div>";
       // this is done using  using System.Net.Mail; & using System.Net; 
        using (MailMessage mail = new MailMessage())
        {
            mail.From = new MailAddress(emailFrom);
            mail.To.Add(emailTo);
            mail.Subject = subject;
            mail.Body = body;
            mail.IsBodyHtml = true;
            // Can set to false, if you are sending pure text.

            using (SmtpClient smtp = new SmtpClient(smtpAddress, portNumber))
            {
                smtp.Credentials = new NetworkCredential(emailFrom, password);
                smtp.EnableSsl = enableSSL;
                smtp.Send(mail);
            }
        }
    }

How to select <td> of the <table> with javascript?

There are a lot of ways to accomplish this, and this is but one of them.

$("table").find("tbody td").eq(0).children().first()

How do I select text nodes with jQuery?

I was getting a lot of empty text nodes with the accepted filter function. If you're only interested in selecting text nodes that contain non-whitespace, try adding a nodeValue conditional to your filter function, like a simple $.trim(this.nodevalue) !== '':

$('element')
    .contents()
    .filter(function(){
        return this.nodeType === 3 && $.trim(this.nodeValue) !== '';
    });

http://jsfiddle.net/ptp6m97v/

Or to avoid strange situations where the content looks like whitespace, but is not (e.g. the soft hyphen &shy; character, newlines \n, tabs, etc.), you can try using a Regular Expression. For example, \S will match any non-whitespace characters:

$('element')
        .contents()
        .filter(function(){
            return this.nodeType === 3 && /\S/.test(this.nodeValue);
        });

How to apply style classes to td classes?

If I remember well, some CSS properties you apply to table are not inherited as expected. So you should indeed apply the style directly to td,tr and th elements.

If you need to add styling to each column, use the <col> element in your table.

See an example here: http://jsfiddle.net/GlauberRocha/xkuRA/2/

NB: You can't have a margin in a td. Use padding instead.

How to produce a range with step n in bash? (generate a sequence of numbers with increments)

Pure Bash, without an extra process:

for (( COUNTER=0; COUNTER<=10; COUNTER+=2 )); do
    echo $COUNTER
done

simple vba code gives me run time error 91 object variable or with block not set

Check the version of the excel, if you are using older version then Value2 is not available for you and thus it is showing an error, while it will work with 2007+ version. Or the other way, the object is not getting created and thus the Value2 property is not available for the object.

Python readlines() usage and efficient practice for reading

The short version is: The efficient way to use readlines() is to not use it. Ever.


I read some doc notes on readlines(), where people has claimed that this readlines() reads whole file content into memory and hence generally consumes more memory compared to readline() or read().

The documentation for readlines() explicitly guarantees that it reads the whole file into memory, and parses it into lines, and builds a list full of strings out of those lines.

But the documentation for read() likewise guarantees that it reads the whole file into memory, and builds a string, so that doesn't help.


On top of using more memory, this also means you can't do any work until the whole thing is read. If you alternate reading and processing in even the most naive way, you will benefit from at least some pipelining (thanks to the OS disk cache, DMA, CPU pipeline, etc.), so you will be working on one batch while the next batch is being read. But if you force the computer to read the whole file in, then parse the whole file, then run your code, you only get one region of overlapping work for the entire file, instead of one region of overlapping work per read.


You can work around this in three ways:

  1. Write a loop around readlines(sizehint), read(size), or readline().
  2. Just use the file as a lazy iterator without calling any of these.
  3. mmap the file, which allows you to treat it as a giant string without first reading it in.

For example, this has to read all of foo at once:

with open('foo') as f:
    lines = f.readlines()
    for line in lines:
        pass

But this only reads about 8K at a time:

with open('foo') as f:
    while True:
        lines = f.readlines(8192)
        if not lines:
            break
        for line in lines:
            pass

And this only reads one line at a time—although Python is allowed to (and will) pick a nice buffer size to make things faster.

with open('foo') as f:
    while True:
        line = f.readline()
        if not line:
            break
        pass

And this will do the exact same thing as the previous:

with open('foo') as f:
    for line in f:
        pass

Meanwhile:

but should the garbage collector automatically clear that loaded content from memory at the end of my loop, hence at any instant my memory should have only the contents of my currently processed file right ?

Python doesn't make any such guarantees about garbage collection.

The CPython implementation happens to use refcounting for GC, which means that in your code, as soon as file_content gets rebound or goes away, the giant list of strings, and all of the strings within it, will be freed to the freelist, meaning the same memory can be reused again for your next pass.

However, all those allocations, copies, and deallocations aren't free—it's much faster to not do them than to do them.

On top of that, having your strings scattered across a large swath of memory instead of reusing the same small chunk of memory over and over hurts your cache behavior.

Plus, while the memory usage may be constant (or, rather, linear in the size of your largest file, rather than in the sum of your file sizes), that rush of mallocs to expand it the first time will be one of the slowest things you do (which also makes it much harder to do performance comparisons).


Putting it all together, here's how I'd write your program:

for filename in os.listdir(input_dir):
    with open(filename, 'rb') as f:
        if filename.endswith(".gz"):
            f = gzip.open(fileobj=f)
        words = (line.split(delimiter) for line in f)
        ... my logic ...  

Or, maybe:

for filename in os.listdir(input_dir):
    if filename.endswith(".gz"):
        f = gzip.open(filename, 'rb')
    else:
        f = open(filename, 'rb')
    with contextlib.closing(f):
        words = (line.split(delimiter) for line in f)
        ... my logic ...

ORA-12528: TNS Listener: all appropriate instances are blocking new connections. Instance "CLRExtProc", status UNKNOWN

I had this problem on my developent environment with Visual Studio.

What helped me was to Clean Solution in Visual Studio and then do a rebuild.

'NoneType' object is not subscriptable?

list1 = ["name1", "info1", 10]
list2 = ["name2", "info2", 30]
list3 = ["name3", "info3", 50]

def printer(*lists):
    for _list in lists:
        for ele in _list:
            print(ele, end = ", ")
        print()

printer(list1, list2, list3)

Python error when trying to access list by index - "List indices must be integers, not str"

player['score'] is your problem. player is apparently a list which means that there is no 'score' element. Instead you would do something like:

name, score = player[0], player[1]
return name + ' ' + str(score)

Of course, you would have to know the list indices (those are the 0 and 1 in my example).

Something like player['score'] is allowed in python, but player would have to be a dict.

You can read more about both lists and dicts in the python documentation.

Format number to 2 decimal places

Show as decimal Select ifnull(format(100.00, 1, 'en_US'), 0) 100.0

Show as Percentage Select concat(ifnull(format(100.00, 0, 'en_US'), 0), '%') 100%

How to get my activity context?

The best and easy way to get the activity context is putting .this after the name of the Activity. For example: If your Activity's name is SecondActivity, its context will be SecondActivity.this

How to re-render flatlist?

For quick and simple solution Try:

  1. set extra data to a boolean value.

    extraData={this.state.refresh}

  2. Toggle the value of boolean state when you want to re-render/refresh list

    this.setState({ 
        refresh: !this.state.refresh
    })
    

How to display an activity indicator with text on iOS 8 with Swift?

You can create your own. For example:

Create a view with white background and rounded corners:

var view = UIView(frame: CGRect(x: 0, y: 0, width: 300, height: 50))
view.backgroundColor = UIColor.whiteColor()
view.layer.cornerRadius = 10

Add two subviews, a UIActivityIndicatorView and a UILabel:

var wait = UIActivityIndicatorView(frame: CGRect(x: 0, y: 0, width: 50, height: 50))
wait.color = UIColor.blackColor()
wait.hidesWhenStopped = false


var text = UILabel(frame: CGRect(x: 60, y: 0, width: 200, height: 50))
text.text = "Processing..."

view.addSubview(wait)
view.addSubview(text)

IN vs OR in the SQL WHERE Clause

OR makes sense (from readability point of view), when there are less values to be compared. IN is useful esp. when you have a dynamic source, with which you want values to be compared.

Another alternative is to use a JOIN with a temporary table.
I don't think performance should be a problem, provided you have necessary indexes.

How to Add Date Picker To VBA UserForm

You could try the "Microsoft Date and Time Picker Control". To use it, in the Toolbox, you right-click and choose "Additional Controls...". Then you check "Microsoft Date and Time Picker Control 6.0" and OK. You will have a new control in the Toolbox to do what you need.

I just found some printscreen of this on : http://www.logicwurks.com/CodeExamplePages/EDatePickerControl.html Forget the procedures, just check the printscreens.

How to select a drop-down menu value with Selenium using Python?

In this way you can select all the options in any dropdowns.

driver.get("https://www.spectrapremium.com/en/aftermarket/north-america")

print( "The title is  : " + driver.title)

inputs = Select(driver.find_element_by_css_selector('#year'))

input1 = len(inputs.options)

for items in range(input1):

    inputs.select_by_index(items)
    time.sleep(1)

Read a HTML file into a string variable in memory

What kind of processing are you trying to do? You can do XmlDocument doc = new XmlDocument(); followed by doc.Load(filename). Then the XML document can be parsed in memory.

Read here for more information on XmlDocument:

Set max-height on inner div so scroll bars appear, but not on parent div

This would work just fine, set the height to desired pixel

#inner-right{
            height: 100px;
            overflow:auto;
            }

Web.Config Debug/Release

To make the transform work in development (using F5 or CTRL + F5) I drop ctt.exe (https://ctt.codeplex.com/) in the packages folder (packages\ConfigTransform\ctt.exe).

Then I register a pre- or post-build event in Visual Studio...

$(SolutionDir)packages\ConfigTransform\ctt.exe source:"$(ProjectDir)connectionStrings.config" transform:"$(ProjectDir)connectionStrings.$(ConfigurationName).config" destination:"$(ProjectDir)connectionStrings.config"
$(SolutionDir)packages\ConfigTransform\ctt.exe source:"$(ProjectDir)web.config" transform:"$(ProjectDir)web.$(ConfigurationName).config" destination:"$(ProjectDir)web.config"

For the transforms I use SlowCheeta VS extension (https://visualstudiogallery.msdn.microsoft.com/69023d00-a4f9-4a34-a6cd-7e854ba318b5).

Display last git commit comment

To start with git log -1 --pretty='%s'

But the below one covers all the cases,

git log --pretty='format:%Creset%s' --no-merges -1

  • No unwanted white spaces
  • Discards merge commits
  • No commit id, date, Displays only the messages.

Paste & see for yourself

Python error: "IndexError: string index out of range"

This error would happen when the number of guesses (so_far) is less than the length of the word. Did you miss an initialization for the variable so_far somewhere, that sets it to something like

so_far = " " * len(word)

?

Edit:

try something like

print "%d / %d" % (new, so_far)

before the line that throws the error, so you can see exactly what goes wrong. The only thing I can think of is that so_far is in a different scope, and you're not actually using the instance you think.

Finding which process was killed by Linux OOM killer

Now dstat provides the feature to find out in your running system which process is candidate for getting killed by oom mechanism

dstat --top-oom
 --out-of-memory---
  kill score
 java           77
 java           77
 java           77

and as per man page

  --top-oom
          show process that will be killed by OOM the first

CSS scrollbar style cross browser

Scrollbar CSS styles are an oddity invented by Microsoft developers. They are not part of the W3C standard for CSS and therefore most browsers just ignore them.

"Error 404 Not Found" in Magento Admin Login Page

Finally, I found the solution to my problem.

I looked into the Magento system log file (var/log/system.log). There I saw the exact error.

The error is as below:-

Recoverable Error: Argument 1 passed to Mage_Core_Model_Store::setWebsite() must be an instance of Mage_Core_Model_Website, null given, called in YOUR_PATH\app\code\core\Mage\Core\Model\App.php on line 555 and defined in YOUR_PATH\app\code\core\Mage\Core\Model\Store.php on line 285

Recoverable Error: Argument 1 passed to Mage_Core_Model_Store_Group::setWebsite() must be an instance of Mage_Core_Model_Website, null given, called in YOUR_PATH\app\code\core\Mage\Core\Model\App.php on line 575 and defined in YOUR_PATH\app\code\core\Mage\Core\Model\Store\Group.php on line 227

Actually, I had this error before. But, error display message like Error: 404 Not Found was new to me.

The reason for this error is that store_id and website_id for admin should be set to 0 (zero). But, when you import database to new server, somehow these values are not set to 0.

Open PhpMyAdmin and run the following query in your database:-

SET FOREIGN_KEY_CHECKS=0;
UPDATE `core_store` SET store_id = 0 WHERE code='admin';
UPDATE `core_store_group` SET group_id = 0 WHERE name='Default';
UPDATE `core_website` SET website_id = 0 WHERE code='admin';
UPDATE `customer_group` SET customer_group_id = 0 WHERE customer_group_code='NOT LOGGED IN';
SET FOREIGN_KEY_CHECKS=1;

I have written about this problem and solution over here:-

Magento: Solution to "Error: 404 Not Found" in Admin Login Page

JQuery - Get select value

val() returns the value of the <select> element, i.e. the value attribute of the selected <option> element.

Since you actually want the inner text of the selected <option> element, you should match that element and use text() instead:

var nationality = $("#dancerCountry option:selected").text();

C#: How to make pressing enter in a text box trigger a button, yet still allow shortcuts such as "Ctrl+A" to get through?

https://stackoverflow.com/a/16350929/11860907

If you add e.SuppressKeyPress = true; as shown in the answer in this link you will suppress the annoying ding sound that occurs.

How to invoke function from external .c file in C?

use #include "ClasseAusiliaria.c" [Dont use angle brackets (< >) ]

and I prefer save file with .h extension in the same Directory/folder.

#include "ClasseAusiliaria.h"

What is referencedColumnName used for in JPA?

  • name attribute points to the column containing the asociation, i.e. column name of the foreign key
  • referencedColumnName attribute points to the related column in asociated/referenced entity, i.e. column name of the primary key

You are not required to fill the referencedColumnName if the referenced entity has single column as PK, because there is no doubt what column it references (i.e. the Address single column ID).

@ManyToOne
@JoinColumn(name="ADDR_ID")
public Address getAddress() { return address; }

However if the referenced entity has PK that spans multiple columns the order in which you specify @JoinColumn annotations has significance. It might work without the referencedColumnName specified, but that is just by luck. So you should map it like this:

@ManyToOne
@JoinColumns({
    @JoinColumn(name="ADDR_ID", referencedColumnName="ID"),
    @JoinColumn(name="ADDR_ZIP", referencedColumnName="ZIP")
})
public Address getAddress() { return address; }

or in case of ManyToMany:

@ManyToMany
@JoinTable(
    name="CUST_ADDR",
    joinColumns=
        @JoinColumn(name="CUST_ID"),
    inverseJoinColumns={
        @JoinColumn(name="ADDR_ID", referencedColumnName="ID"),
        @JoinColumn(name="ADDR_ZIP", referencedColumnName="ZIP")
    }
)

Real life example

Two queries generated by Hibernate of the same join table mapping, both without referenced column specified. Only the order of @JoinColumn annotations were changed.

/* load collection Client.emails */ 
select 
emails0_.id_client as id1_18_1_,
emails0_.rev as rev18_1_,
emails0_.id_email as id3_1_,
email1_.id_email as id1_6_0_

from client_email emails0_ 
inner join email email1_ on emails0_.id_email=email1_.id_email 

where emails0_.id_client='2' and 
emails0_.rev='18'
/* load collection Client.emails */ 
select
emails0_.rev as rev18_1_,
emails0_.id_client as id2_18_1_,
emails0_.id_email as id3_1_, 
email1_.id_email as id1_6_0_

from client_email emails0_ 
inner join email email1_ on emails0_.id_email=email1_.id_email 

where emails0_.rev='2' and 
emails0_.id_client='18'

We are querying a join table to get client's emails. The {2, 18} is composite ID of Client. The order of column names is determined by your order of @JoinColumn annotations. The order of both integers is always the same, probably sorted by hibernate and that's why proper alignment with join table columns is required and we can't or should rely on mapping order.

The interesting thing is the order of the integers does not match the order in which they are mapped in the entity - in that case I would expect {18, 2}. So it seems the Hibernate is sorting the column names before it use them in query. If this is true and you would order your @JoinColumn in the same way you would not need referencedColumnName, but I say this only for illustration.

Properly filled referencedColumnName attributes result in exactly same query without the ambiguity, in my case the second query (rev = 2, id_client = 18).

Android ADB stop application command like "force-stop" for non rooted device

If you have a rooted device you can use kill command

Connect to your device with adb:

adb shell

Once the session is established, you have to escalade privileges:

su

Then

ps

will list running processes. Note down the PID of the process you want to terminate. Then get rid of it

kill PID

How to create a zip file in Java

public static void zipFromTxt(String zipFilePath, String txtFilePath) {
    Assert.notNull(zipFilePath, "Zip file path is required");
    Assert.notNull(txtFilePath, "Txt file path is required");
    zipFromTxt(new File(zipFilePath), new File(txtFilePath));
}

public static void zipFromTxt(File zipFile, File txtFile) {
    ZipOutputStream out = null;
    FileInputStream in = null;
    try {
        Assert.notNull(zipFile, "Zip file is required");
        Assert.notNull(txtFile, "Txt file is required");
        out = new ZipOutputStream(new FileOutputStream(zipFile));
        in = new FileInputStream(txtFile);
        out.putNextEntry(new ZipEntry(txtFile.getName()));
        int len;
        byte[] buffer = new byte[1024];
        while ((len = in.read(buffer)) > 0) {
            out.write(buffer, 0, len);
            out.flush();
        }
    } catch (Exception e) {
        log.info("Zip from txt occur error,Detail message:{}", e.toString());
    } finally {
        try {
            if (in != null) in.close();
            if (out != null) {
                out.closeEntry();
                out.close();
            }
        } catch (Exception e) {
            log.info("Zip from txt close error,Detail message:{}", e.toString());
        }
    }
}

select a value where it doesn't exist in another table

This would select 4 in your case

SELECT ID FROM TableA WHERE ID NOT IN (SELECT ID FROM TableB)

This would delete them

DELETE FROM TableA WHERE ID NOT IN (SELECT ID FROM TableB)

Regex matching in a Bash if statement

There are a couple of important things to know about bash's [[ ]] construction. The first:

Word splitting and pathname expansion are not performed on the words between the [[ and ]]; tilde expansion, parameter and variable expansion, arithmetic expansion, command substitution, process substitution, and quote removal are performed.

The second thing:

An additional binary operator, ‘=~’, is available,... the string to the right of the operator is considered an extended regular expression and matched accordingly... Any part of the pattern may be quoted to force it to be matched as a string.

Consequently, $v on either side of the =~ will be expanded to the value of that variable, but the result will not be word-split or pathname-expanded. In other words, it's perfectly safe to leave variable expansions unquoted on the left-hand side, but you need to know that variable expansions will happen on the right-hand side.

So if you write: [[ $x =~ [$0-9a-zA-Z] ]], the $0 inside the regex on the right will be expanded before the regex is interpreted, which will probably cause the regex to fail to compile (unless the expansion of $0 ends with a digit or punctuation symbol whose ascii value is less than a digit). If you quote the right-hand side like-so [[ $x =~ "[$0-9a-zA-Z]" ]], then the right-hand side will be treated as an ordinary string, not a regex (and $0 will still be expanded). What you really want in this case is [[ $x =~ [\$0-9a-zA-Z] ]]

Similarly, the expression between the [[ and ]] is split into words before the regex is interpreted. So spaces in the regex need to be escaped or quoted. If you wanted to match letters, digits or spaces you could use: [[ $x =~ [0-9a-zA-Z\ ] ]]. Other characters similarly need to be escaped, like #, which would start a comment if not quoted. Of course, you can put the pattern into a variable:

pat="[0-9a-zA-Z ]"
if [[ $x =~ $pat ]]; then ...

For regexes which contain lots of characters which would need to be escaped or quoted to pass through bash's lexer, many people prefer this style. But beware: In this case, you cannot quote the variable expansion:

# This doesn't work:
if [[ $x =~ "$pat" ]]; then ...

Finally, I think what you are trying to do is to verify that the variable only contains valid characters. The easiest way to do this check is to make sure that it does not contain an invalid character. In other words, an expression like this:

valid='0-9a-zA-Z $%&#' # add almost whatever else you want to allow to the list
if [[ ! $x =~ [^$valid] ]]; then ...

! negates the test, turning it into a "does not match" operator, and a [^...] regex character class means "any character other than ...".

The combination of parameter expansion and regex operators can make bash regular expression syntax "almost readable", but there are still some gotchas. (Aren't there always?) One is that you could not put ] into $valid, even if $valid were quoted, except at the very beginning. (That's a Posix regex rule: if you want to include ] in a character class, it needs to go at the beginning. - can go at the beginning or the end, so if you need both ] and -, you need to start with ] and end with -, leading to the regex "I know what I'm doing" emoticon: [][-])

Python class inherits object

The syntax of the class creation statement:

class <ClassName>(superclass):
    #code follows

In the absence of any other superclasses that you specifically want to inherit from, the superclass should always be object, which is the root of all classes in Python.

object is technically the root of "new-style" classes in Python. But the new-style classes today are as good as being the only style of classes.

But, if you don't explicitly use the word object when creating classes, then as others mentioned, Python 3.x implicitly inherits from the object superclass. But I guess explicit is always better than implicit (hell)

Reference

What's the difference between primitive and reference types?

Primitive data type

The primitive data type is a basic type provided by a programming language as a basic building block. So it's predefined data types. A primitive type has always a value. It storing simple value.

It specifies the size and type of variable values, so the size of a primitive type depends on the data type and it has no additional methods.

And these are reserved keywords in the language. So we can't use these names as variable, class or method name. A primitive type starts with a lowercase letter. When declaring the primitive types we don't need to allocate memory. (memory is allocated and released by JRE-Java Runtime Environment in Java)

8 primitive data types in Java

+================+=========+===================================================================================+
| Primitive type | Size    | Description                                                                       |
+================+=========+===================================================================================+
| byte           | 1 byte  | Stores whole numbers from -128 to 127                                             |
+----------------+---------+-----------------------------------------------------------------------------------+
| short          | 2 bytes | Stores whole numbers from -32,768 to 32,767                                       |
+----------------+---------+-----------------------------------------------------------------------------------+
| int            | 4 bytes | Stores whole numbers from -2,147,483,648 to 2,147,483,647                         |
+----------------+---------+-----------------------------------------------------------------------------------+
| long           | 8 bytes | Stores whole numbers from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 |
+----------------+---------+-----------------------------------------------------------------------------------+
| float          | 4 bytes | Stores fractional numbers. Sufficient for storing 6 to 7 decimal digits           |
+----------------+---------+-----------------------------------------------------------------------------------+
| double         | 8 bytes | Stores fractional numbers. Sufficient for storing 15 decimal digits               |
+----------------+---------+-----------------------------------------------------------------------------------+
| char           | 2 bytes | Stores a single character/letter or ASCII values                                  |
+----------------+---------+-----------------------------------------------------------------------------------+
| boolean        | 1 bit   | Stores true or false values                                                       |
+----------------+---------+-----------------------------------------------------------------------------------+

Reference data type

Reference data type refers to objects. Most of these types are not defined by programming language(except for String, arrays in JAVA). Reference types of value can be null. It storing an address of the object it refers to. Reference or non-primitive data types have all the same size. and reference types can be used to call methods to perform certain operations.

when declaring the reference type need to allocate memory. In Java, we used new keyword to allocate memory, or alternatively, call a factory method.

Example:

List< String > strings = new ArrayList<>() ;  // Calling `new`  to instantiate an object and thereby allocate memory.

Point point = Point(1,2) ;           // Calling a factory method.

Write to custom log file from a Bash script

@chepner make a good point that logger is dedicated to logging messages.

I do need to mention that @Thomas Haratyk simply inquired why I didn't simply use echo.

At the time, I didn't know about echo, as I'm learning shell-scripting, but he was right.

My simple solution is now this:

#!/bin/bash
echo "This logs to where I want, but using echo" > /var/log/mycustomlog

The example above will overwrite the file after the >

So, I can append to that file with this:

#!/bin/bash
echo "I will just append to my custom log file" >> /var/log/customlog

Thanks guys!

  • on a side note, it's simply my personal preference to keep my personal logs in /var/log/, but I'm sure there are other good ideas out there. And since I didn't create a daemon, /var/log/ probably isn't the best place for my custom log file. (just saying)

Return value using String result=Command.ExecuteScalar() error occurs when result returns null

Value is not null, but DBNull.Value.

object value = cmd.ExecuteScalar();
if(value == DBNull.Value)

rsync: how can I configure it to create target directory on server?

Assuming you are using ssh to connect rsync, what about to send a ssh command before:

ssh user@server mkdir -p existingdir/newdir

if it already exists, nothing happens

Regular Expression: Allow letters, numbers, and spaces (with at least one letter or number)

You can use a lookaround:

^(?=.*[A-Za-z0-9])[A-Za-z0-9 _]*$

It will check ahead that the string has a letter or number, if it does it will check that the rest of the chars meet your requirements. This can probably be improved upon, but it seems to work with my tests.

UPDATE:

Adding modifications suggested by Chris Lutz:

^(?=.*[^\W_])[\w ]*$/

Convert to binary and keep leading zeros in Python

Use the format() function:

>>> format(14, '#010b')
'0b00001110'

The format() function simply formats the input following the Format Specification mini language. The # makes the format include the 0b prefix, and the 010 size formats the output to fit in 10 characters width, with 0 padding; 2 characters for the 0b prefix, the other 8 for the binary digits.

This is the most compact and direct option.

If you are putting the result in a larger string, use an formatted string literal (3.6+) or use str.format() and put the second argument for the format() function after the colon of the placeholder {:..}:

>>> value = 14
>>> f'The produced output, in binary, is: {value:#010b}'
'The produced output, in binary, is: 0b00001110'
>>> 'The produced output, in binary, is: {:#010b}'.format(value)
'The produced output, in binary, is: 0b00001110'

As it happens, even for just formatting a single value (so without putting the result in a larger string), using a formatted string literal is faster than using format():

>>> import timeit
>>> timeit.timeit("f_(v, '#010b')", "v = 14; f_ = format")  # use a local for performance
0.40298633499332936
>>> timeit.timeit("f'{v:#010b}'", "v = 14")
0.2850222919951193

But I'd use that only if performance in a tight loop matters, as format(...) communicates the intent better.

If you did not want the 0b prefix, simply drop the # and adjust the length of the field:

>>> format(14, '08b')
'00001110'

CORS: credentials mode is 'include'

Just add Axios.defaults.withCredentials=true instead of ({credentials: true}) in client side, and change app.use(cors()) to

app.use(cors(
  {origin: ['your client side server'],
  methods: ['GET', 'POST'],
  credentials:true,
}
))

linux find regex

You should have a look on the -regextype argument of find, see manpage:

      -regextype type
          Changes the regular expression syntax understood by -regex and -iregex 
          tests which occur later on the command line.  Currently-implemented  
          types  are  emacs (this is the default), posix-awk, posix-basic, 
          posix-egrep and posix-extended. 

I guess the emacs type doesn't support the [[:digit:]] construct. I tried it with posix-extended and it worked as expected:

find -regextype posix-extended -regex '.*[1234567890]'
find -regextype posix-extended -regex '.*[[:digit:]]'

Shorthand for if-else statement

You can use an object as a map:

  var hasName = ({
        "true"  : "Y",
        "false" : "N"
  })[name];

This also scales nicely for many options

  var hasName = ({
        "true"          : "Y",
        "false"         : "N",
        "fileNotFound"  : "O"
  })[name];

(Bonus point for people getting the reference)

Note: you should use actual booleans instead of the string value "true" for your variables indicating truth values.

Execute JavaScript code stored as a string

Not sure if this is cheating or not:

window.say = function(a) { alert(a); };

var a = "say('hello')";

var p = /^([^(]*)\('([^']*)'\).*$/;                 // ["say('hello')","say","hello"]

var fn = window[p.exec(a)[1]];                      // get function reference by name

if( typeof(fn) === "function") 
    fn.apply(null, [p.exec(a)[2]]);                 // call it with params

Launch Bootstrap Modal on page load

You can activate the modal without writing any JavaScript simply via data attributes.

The option "show" set to true shows the modal when initialized:

<div class="modal fade" tabindex="-1" role="dialog" data-show="true"></div>

How do I find the MySQL my.cnf location

For Ubuntu 16: /etc/mysql/mysql.conf.d/mysqld.cnf

How do I check if the mouse is over an element in jQuery?

You can use jQuery's mouseenter and mouseleave events. You can set a flag when the mouse enters the desired area and unset the flag when it leaves the area.

Javascript array search and remove string?

Simple solution (ES6)

If you don't have duplicate element

Array.prototype.remove = function(elem) {
  var indexElement = this.findIndex(el => el === elem);
  if (indexElement != -1)
    this.splice(indexElement, 1);
  return this;
};   

Online demo (fiddle)