Programs & Examples On #Urbanairship.com

Urban Airship is an engine for mobile apps. It provides messaging and content delivery tools, including push notifications, rich media messaging, location targeting, and Digital Wallet services. You can also contact Urban Airship for help directly at [email protected] or visit their forums at http://support.urbanairship.com .

How to redirect to a route in laravel 5 by using href tag if I'm not using blade or any template?

In addition to @chanafdo answer, you can use route name

when working with laravel blade

<a href="{{route('login')}}">login here</a> with parameter in route name

when go to url like URI: profile/{id} <a href="{{route('profile', ['id' => 1])}}">login here</a>

without blade

<a href="<?php echo route('login')?>">login here</a>

with parameter in route name

when go to url like URI: profile/{id} <a href="<?php echo route('profile', ['id' => 1])?>">login here</a>

As of laravel 5.2 you can use @php @endphp to create as <?php ?> in laravel blade. Using blade your personal opinion but I suggest to use it. Learn it. It has many wonderful features as template inheritance, Components & Slots,subviews etc...

Multiline string literal in C#

You can use the @ symbol in front of a string to form a verbatim string literal:

string query = @"SELECT foo, bar
FROM table
WHERE id = 42";

You also do not have to escape special characters when you use this method, except for double quotes as shown in Jon Skeet's answer.

fatal error LNK1104: cannot open file 'libboost_system-vc110-mt-gd-1_51.lib'

Yet another solution:

I was stumped because I was including boost_regex-vc120-mt-gd-1_58.lib in my Link->Additional Dependencies property, but the link kept telling me it couldn't open libboost_regex-vc120-mt-gd-1_58.lib (note the lib prefix). I didn't specify libboost_regex-vc120-mt-gd-1_58.lib.

I was trying to use (and had built) the boost dynamic libraries (.dlls) but did not have the BOOST_ALL_DYN_LINK macro defined. Apparently there are hints in the compile to include a library, and without BOOST_ALL_DYN_LINK it looks for the static library (with the lib prefix), not the dynamic library (without a lib prefix).

How to iterate through property names of Javascript object?

Use for...in loop:

for (var key in obj) {
   console.log(' name=' + key + ' value=' + obj[key]);

   // do some more stuff with obj[key]
}

How to format LocalDate to string?

Could be short as:

LocalDate.now().format(DateTimeFormatter.ofPattern("dd/MM/yyyy"));

How can I extract the folder path from file path in Python?

Here is my little utility helper for splitting paths int file, path tokens:

import os    
# usage: file, path = splitPath(s)
def splitPath(s):
    f = os.path.basename(s)
    p = s[:-(len(f))-1]
    return f, p

Setting a checkbox as checked with Vue.js

I use both hidden and checkbox type input to ensure either 0 or 1 submitted to the form. Make sure the field name are the same so only one input will be sent to the server.

<input type="hidden" :name="fieldName" value="0">
<input type="checkbox" :name="fieldName" value="1" :checked="checked">

How do you grep a file and get the next 5 lines

Some awk version.

awk '/19:55/{c=5} c-->0'
awk '/19:55/{c=5} c && c--'

When pattern found, set c=5
If c is true, print and decrease number of c

JS: Failed to execute 'getComputedStyle' on 'Window': parameter is not of type 'Element'

I had the same error on my Angular6 project. none of those solutions seemed to work out for me. turned out that the problem was due to an element which was specified as dropdown but it didn't have dropdown options in it. take a look at code below:

<span class="nav-link" id="navbarDropdownMenuLink" data-toggle="dropdown"
                          aria-haspopup="true" aria-expanded="false">
                        <i class="material-icons "
                           style="font-size: 2rem">notifications</i>
                        <span class="notification"></span>
                        <p>
                            <span class="d-lg-none d-md-block">Some Actions</span>
                        </p>
                    </span>
                    <div class="dropdown-menu dropdown-menu-left"
                         *ngIf="global.localStorageItem('isInSadHich')"
                         aria-labelledby="navbarDropdownMenuLink">
                                        <a class="dropdown-item" href="#">You have 5 new tasks</a>
                                        <a class="dropdown-item" href="#">You're now friend with Andrew</a>
                                        <a class="dropdown-item" href="#">Another Notification</a>
                                        <a class="dropdown-item" href="#">Another One</a>
                    </div>

removing the code data-toggle="dropdown" aria-haspopup="true" aria-expanded="false" solved the problem.

I myself think that by each click on the first span element, the scope expected to set style for dropdown children which did not existed in the parent span, so it threw error.

How do you debug React Native?

For android app .Press Ctrl+M select debug js remotely it will open a new window in chrome with url http://localhost:8081/debugger-ui. You can now debug the app in chrome browser

How can I use a search engine to search for special characters?

duckduckgo.com doesn't ignore special characters, at least if the whole string is between ""

https://duckduckgo.com/?q=%22*222%23%22

Operator overloading ==, !=, Equals

As Selman22 said, you are overriding the default object.Equals method, which accepts an object obj and not a safe compile time type.

In order for that to happen, make your type implement IEquatable<Box>:

public class Box : IEquatable<Box>
{
    double height, length, breadth;

    public static bool operator ==(Box obj1, Box obj2)
    {
        if (ReferenceEquals(obj1, obj2))
        {
            return true;
        }
        if (ReferenceEquals(obj1, null))
        {
            return false;
        }
        if (ReferenceEquals(obj2, null))
        {
            return false;
        }

        return obj1.Equals(obj2);
    }

    public static bool operator !=(Box obj1, Box obj2)
    {
        return !(obj1 == obj2);
    }

    public bool Equals(Box other)
    {
        if (ReferenceEquals(other, null))
        {
            return false;
        }
        if (ReferenceEquals(this, other))
        {
            return true;
        }

        return height.Equals(other.height) 
               && length.Equals(other.length) 
               && breadth.Equals(other.breadth);
    }

    public override bool Equals(object obj)
    {
        return Equals(obj as Box);
    }

    public override int GetHashCode()
    {
        unchecked
        {
            int hashCode = height.GetHashCode();
            hashCode = (hashCode * 397) ^ length.GetHashCode();
            hashCode = (hashCode * 397) ^ breadth.GetHashCode();
            return hashCode;
        }
    }
}

Another thing to note is that you are making a floating point comparison using the equality operator and you might experience a loss of precision.

How to cast or convert an unsigned int to int in C?

If you have a variable unsigned int x;, you can convert it to an int using (int)x.

How do I get the directory of the PowerShell script I execute?

PowerShell 3 has the $PSScriptRoot automatic variable:

Contains the directory from which a script is being run.

In Windows PowerShell 2.0, this variable is valid only in script modules (.psm1). Beginning in Windows PowerShell 3.0, it is valid in all scripts.

Don't be fooled by the poor wording. PSScriptRoot is the directory of the current file.

In PowerShell 2, you can calculate the value of $PSScriptRoot yourself:

# PowerShell v2
$PSScriptRoot = Split-Path -Parent -Path $MyInvocation.MyCommand.Definition

Add floating point value to android resources/values

I used a style to solve this issue. The official link is here.

Pretty useful stuff. You make a file to hold your styles (like "styles.xml"), and define them inside it. You then reference the styles in your layout (like "main.xml").

Here's a sample style that does what you want:

<style name="text_line_spacing">
   <item name="android:lineSpacingMultiplier">1.4</item>
</style>

Let's say you want to alter a simple TextView with this. In your layout file you'd type:

<TextView
   style="@style/summary_text"
   ...
   android:text="This sentence has 1.4 times more spacing than normal."
/>

Try it--this is essentially how all the built-in UI is done on the android. And by using styles, you have the option to modify all sorts of other aspects of your Views as well.

Select SQL Server database size

SELECT
    DB_NAME (database_id) as [Database Name],
    name as [Database File Name],
    [Type] = CASE WHEN Type_Desc = 'ROWS' THEN 'Data File(s)'
            WHEN Type_Desc = 'LOG'  THEN 'Log File(s)'
            ELSE Type_Desc END,
    size*8/1024 as 'Size (MB)',
    physical_name as [Database_File_Location]
FROM sys.master_files
ORDER BY 1,3

Output

Database Name               Database File Name              Type                Size (MB)   Database_File_Location
--------------------------- ------------------------------- ------------------- ----------- ---------------------------------------------------------------
AdventureWorksDW2017        AdventureWorksDW2017            Data File(s)        136         E:\MSSQL14.MSSQLSERVER\MSSQL\DATA\AdventureWorksDW2017.mdf
AdventureWorksDW2017        AdventureWorksDW2017_log        Log File(s)         72          E:\MSSQL14.MSSQLSERVER\MSSQL\DATA\AdventureWorksDW2017_log.ldf
DBA_Admin                   DBA_Admin                       Data File(s)        8           E:\MSSQL14.MSSQLSERVER\MSSQL\DATA\DBA_Admin.mdf
DBA_Admin                   DBA_Admin_log                   Log File(s)         8           E:\MSSQL14.MSSQLSERVER\MSSQL\DATA\DBA_Admin_log.ldf
EventNotifications          EventNotifications              Data File(s)        8           E:\MSSQL14.MSSQLSERVER\MSSQL\DATA\EventNotifications.mdf
EventNotifications          EventNotifications_log          Log File(s)         8           E:\MSSQL14.MSSQLSERVER\MSSQL\DATA\EventNotifications_log.ldf
master                      master                          Data File(s)        4           E:\MSSQL14.MSSQLSERVER\MSSQL\DATA\master.mdf
master                      mastlog                         Log File(s)         2           E:\MSSQL14.MSSQLSERVER\MSSQL\DATA\mastlog.ldf
model                       modeldev                        Data File(s)        8           E:\MSSQL14.MSSQLSERVER\MSSQL\DATA\model.mdf
model                       modellog                        Log File(s)         8           E:\MSSQL14.MSSQLSERVER\MSSQL\DATA\modellog.ldf
msdb                        MSDBData                        Data File(s)        19          E:\MSSQL14.MSSQLSERVER\MSSQL\DATA\MSDBData.mdf
msdb                        MSDBLog                         Log File(s)         13          E:\MSSQL14.MSSQLSERVER\MSSQL\DATA\MSDBLog.ldf
tempdb                      temp2                           Data File(s)        8           E:\MSSQL14.MSSQLSERVER\MSSQL\DATA\tempdb_mssql_2.ndf
tempdb                      temp3                           Data File(s)        8           E:\MSSQL14.MSSQLSERVER\MSSQL\DATA\tempdb_mssql_3.ndf
tempdb                      temp4                           Data File(s)        8           E:\MSSQL14.MSSQLSERVER\MSSQL\DATA\tempdb_mssql_4.ndf
tempdb                      tempdev                         Data File(s)        8           E:\MSSQL14.MSSQLSERVER\MSSQL\DATA\tempdb.mdf
tempdb                      templog                         Log File(s)         8           E:\MSSQL14.MSSQLSERVER\MSSQL\DATA\templog.ldf

How does one create an InputStream from a String?

InputStream in = new ByteArrayInputStream(yourstring.getBytes());

Copy rows from one Datatable to another DataTable?

As a result of the other posts, this is the shortest I could get:

DataTable destTable = sourceTable.Clone();
sourceTable.AsEnumerable().Where(row => /* condition */ ).ToList().ForEach(row => destTable.ImportRow(row));

javascript - replace dash (hyphen) with a space

I think the problem you are facing is almost this: -

str = str.replace("-", ' ');

You need to re-assign the result of the replacement to str, to see the reflected change.

From MSDN Javascript reference: -

The result of the replace method is a copy of stringObj after the specified replacements have been made.

To replace all the -, you would need to use /g modifier with a regex parameter: -

str = str.replace(/-/g, ' ');

Mailbox unavailable. The server response was: 5.7.1 Unable to relay Error

The default configuration of most SMTP servers is not to relay from an untrusted source to outside domains. For example, imagine that you contact the SMTP server for foo.com and ask it to send a message to [email protected]. Because the SMTP server doesn't really know who you are, it will refuse to relay the message. If the server did do that for you, it would be considered an open relay, which is how spammers often do their thing.

If you contact the foo.com mail server and ask it to send mail to [email protected], it might let you do it. It depends on if they trust that you're who you say you are. Often, the server will try to do a reverse DNS lookup, and refuse to send mail if the IP you're sending from doesn't match the IP address of the MX record in DNS. So if you say that you're the bar.com mail server but your IP address doesn't match the MX record for bar.com, then it will refuse to deliver the message.

You'll need to talk to the administrator of that SMTP server to get the authentication information so that it will allow relay for you. You'll need to present those credentials when you contact the SMTP server. Usually it's either a user name/password, or it can use Windows permissions. Depends on the server and how it's configured.

See Unable to send emails to external domain using SMTP for an example of how to send the credentials.

How to fix error "Updating Maven Project". Unsupported IClasspathEntry kind=4?

Before importing the project, it should be converted into eclipse project mvn eclipse: eclipse Then i found the following error. An internal error occurred during: "Importing Maven projects".Unsupported IClasspathEntry kind=4

Where is the value kind = "var" that M2E does not recognize and therefore throws the error.

Now type this. mvn eclipse: clean

Now refresh the project in eclipse or re-import.

Printing with sed or awk a line following a matching pattern

I needed to print ALL lines after the pattern ( ok Ed, REGEX ), so I settled on this one:

sed -n '/pattern/,$p' # prints all lines after ( and including ) the pattern

But since I wanted to print all the lines AFTER ( and exclude the pattern )

sed -n '/pattern/,$p' | tail -n+2  # all lines after first occurrence of pattern

I suppose in your case you can add a head -1 at the end

sed -n '/pattern/,$p' | tail -n+2 | head -1 # prints line after pattern

Uncaught ReferenceError: $ is not defined

You have not referenced a jQuery library.

You'll need to include a line similar to this in your HTML:

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>

Difference Between One-to-Many, Many-to-One and Many-to-Many?

I would explain that way:

OneToOne - OneToOne relationship

@OneToOne
Person person;

@OneToOne
Nose nose;

OneToMany - ManyToOne relationship

@OneToMany
Shepherd> shepherd;

@ManyToOne
List<Sheep> sheeps;

ManyToMany - ManyToMany relationship

@ManyToMany
List<Traveler> travelers;

@ManyToMany
List<Destination> destinations;

Checking letter case (Upper/Lower) within a string in Java

A quick look through the documentation on regular expression sytanx should bring up ways to tell if it contains a lower/upper case character at some point.

import android packages cannot be resolved

May be you are using this checking :

if (Build.VERSION.SDK_INT < Build.VERSION_CODES.KITKAT) {
}

To resolve this you need to import android.provider.DocumentsContract class.

To resolve this issue you'll need to set the build SDK version to 19 (4.4) or higher to have API level 19 symbols available while compiling.

First, use the SDK Manager to download API 19 if you don't have it yet. Then, configure your project to use API 19:

  • In Android Studio: File -> Project Structure -> General Settings -> Project SDK.
  • In Eclipse ADT: Project Properties -> Android -> Project Build Target

I found this answer from here

Thanks .

Why aren't Xcode breakpoints functioning?

This happens from time to time with an iOS project at least. To fix it, I had to reboot the iOS device, quit Xcode, and rebuild the project.

Where are Docker images stored on the host machine?

In Docker for Windows, the logs are here: %USERPROFILE%\AppData\Local\Docker

Replace whitespaces with tabs in linux

better tr command:

tr [:blank:] \\t

This will clean up the output of say, unzip -l , for further processing with grep, cut, etc.

e.g.,

unzip -l some-jars-and-textfiles.zip | tr [:blank:] \\t | cut -f 5 | grep jar

Easiest way to rotate by 90 degrees an image using OpenCV?

Here's my EmguCV (a C# port of OpenCV) solution:

public static Image<TColor, TDepth> Rotate90<TColor, TDepth>(this Image<TColor, TDepth> img)
    where TColor : struct, IColor
    where TDepth : new()
{
    var rot = new Image<TColor, TDepth>(img.Height, img.Width);
    CvInvoke.cvTranspose(img.Ptr, rot.Ptr);
    rot._Flip(FLIP.HORIZONTAL);
    return rot;
}

public static Image<TColor, TDepth> Rotate180<TColor, TDepth>(this Image<TColor, TDepth> img)
    where TColor : struct, IColor
    where TDepth : new()
{
    var rot = img.CopyBlank();
    rot = img.Flip(FLIP.VERTICAL);
    rot._Flip(FLIP.HORIZONTAL);
    return rot;
}

public static void _Rotate180<TColor, TDepth>(this Image<TColor, TDepth> img)
    where TColor : struct, IColor
    where TDepth : new()
{
    img._Flip(FLIP.VERTICAL);
    img._Flip(FLIP.HORIZONTAL);
}

public static Image<TColor, TDepth> Rotate270<TColor, TDepth>(this Image<TColor, TDepth> img)
    where TColor : struct, IColor
    where TDepth : new()
{
    var rot = new Image<TColor, TDepth>(img.Height, img.Width);
    CvInvoke.cvTranspose(img.Ptr, rot.Ptr);
    rot._Flip(FLIP.VERTICAL);
    return rot;
}

Shouldn't be too hard to translate it back into C++.

Determine direct shared object dependencies of a Linux binary?

You can use readelf to explore the ELF headers. readelf -d will list the direct dependencies as NEEDED sections.

 $ readelf -d elfbin

Dynamic section at offset 0xe30 contains 22 entries:
  Tag        Type                         Name/Value
 0x0000000000000001 (NEEDED)             Shared library: [libssl.so.1.0.0]
 0x0000000000000001 (NEEDED)             Shared library: [libc.so.6]
 0x000000000000000c (INIT)               0x400520
 0x000000000000000d (FINI)               0x400758
 ...

jQuery select2 get value of select tag?

To get Select element you can use $('#first').val();

To get the text of selected value - $('#first :selected').text();

Can you please post your select2() function code

Importing a long list of constants to a Python file

And ofcourse you can do:

# a.py
MY_CONSTANT = ...

# b.py
from a import *
print MY_CONSTANT

Why is Ant giving me a Unsupported major.minor version error

If you're getting this error because you're purposefully trying to build to Java 6, but you have Java 7 elsewhere in Eclipse, then it may be because you are referencing a Java 7 tools.jar in a Java 6 environment.

You'll need to install the JDK 6 (not JRE) and add the JRE 6 tools.jar as a User Entry in the Classpath of the build configuration, listed above the JRE 7 tools.jar.

Parse an HTML string with JS

The following function parseHTML will return either :


The code :

function parseHTML(markup) {
    if (markup.toLowerCase().trim().indexOf('<!doctype') === 0) {
        var doc = document.implementation.createHTMLDocument("");
        doc.documentElement.innerHTML = markup;
        return doc;
    } else if ('content' in document.createElement('template')) {
       // Template tag exists!
       var el = document.createElement('template');
       el.innerHTML = markup;
       return el.content;
    } else {
       // Template tag doesn't exist!
       var docfrag = document.createDocumentFragment();
       var el = document.createElement('body');
       el.innerHTML = markup;
       for (i = 0; 0 < el.childNodes.length;) {
           docfrag.appendChild(el.childNodes[i]);
       }
       return docfrag;
    }
}

How to use :

var links = parseHTML('<!doctype html><html><head></head><body><a>Link 1</a><a>Link 2</a></body></html>').getElementsByTagName('a');

How to check compiler log in sql developer?

To see your log in SQL Developer then press:

CTRL+SHIFT + L (or CTRL + CMD + L on macOS)

or

View -> Log

or by using mysql query

show errors;

Rails filtering array of objects by attribute value

If your attachments are

@attachments = Job.find(1).attachments

This will be array of attachment objects

Use select method to filter based on file_type.

@logos = @attachments.select { |attachment| attachment.file_type == 'logo' }
@images = @attachments.select { |attachment| attachment.file_type == 'image' }

This will not trigger any db query.

Shortcut to Apply a Formula to an Entire Column in Excel

Try double-clicking on the bottom right hand corner of the cell (ie on the box that you would otherwise drag).

Creating temporary files in bash

mktemp is probably the most versatile, especially if you plan to work with the file for a while.

You can also use a process substitution operator <() if you only need the file temporarily as input to another command, e.g.:

$ diff <(echo hello world) <(echo foo bar)

Discard all and get clean copy of latest revision?

If you're looking for a method that's easy, then you might want to try this.

I for myself can hardly remember commandlines for all of my tools, so I tend to do it using the UI:


1. First, select "commit"

Commit

2. Then, display ignored files. If you have uncommitted changes, hide them.

Show ignored files

3. Now, select all of them and click "Delete Unversioned".

Delete them

Done. It's a procedure that is far easier to remember than commandline stuff.

Carriage return and Line feed... Are both required in C#?

It depends on where you're displaying the text. On the console or a textbox for example, \n will suffice. On a RichTextBox I think you need both.

how to use DEXtoJar

Follow the below steps to do so_

  1. Rename your APK file(e.g., rename your APK file to .zip Ex- test.apk -> test.zip) & extract resultant zip file.
  2. Copy your .dex file in to dex2jar folder.
  3. Run setclasspath.bat. This should be run because this data is used in the next step.
  4. Go to Windows Command prompt, change the folder path to the path of your dex2jar folder and run the command as follows: d2j-dex2jar.bat classes.dex
  5. enjoy!! Your jar file will be ready in the same folder with name classes_dex2jar.jar.

Hope this helps you and All reading this... :)

LaTeX: remove blank page after a \part or \chapter

A solution that works:

Wrap the part of the document that needs this modified behavior with the code provided below. In my case the portion to wrap is a \part{} and some text following it.

\makeatletter\@openrightfalse
\part{Whatever}

Some text

\chapter{Foo}
\@openrighttrue\makeatother 

The wrapped portion should also include the chapter at the beginning of which this behavior needs to stop. Otherwise LaTeX may generate an empty page before this chapter.

Source: folks at the #latex IRC channel on irc.freenode.net

How do I redirect with JavaScript?

window.location.replace('http://sidanmor.com');

It's better than using window.location.href = 'http://sidanmor.com';

Using replace() is better because it does not keep the originating page in the session history, meaning the user won't get stuck in a never-ending back-button fiasco.

If you want to simulate someone clicking on a link, use window.location.href

If you want to simulate an HTTP redirect, use window.location.replace

For example:

// similar behavior as an HTTP redirect
window.location.replace("http://sidanmor.com");

// similar behavior as clicking on a link
window.location.href = "http://sidanmor.com";

Taken from here: How to redirect to another page in jQuery?

Ansible: how to get output to display

Every Ansible task when run can save its results into a variable. To do this, you have to specify which variable to save the results into. Do this with the register parameter, independently of the module used.

Once you save the results to a variable you can use it later in any of the subsequent tasks. So for example if you want to get the standard output of a specific task you can write the following:

---
- hosts: localhost
  tasks:
    - shell: ls
      register: shell_result

    - debug:
        var: shell_result.stdout_lines

Here register tells ansible to save the response of the module into the shell_result variable, and then we use the debug module to print the variable out.

An example run would look like the this:

PLAY [localhost] ***************************************************************

TASK [command] *****************************************************************
changed: [localhost]

TASK [debug] *******************************************************************
ok: [localhost] => {
    "shell_result.stdout_lines": [
        "play.yml"
    ]
}

Responses can contain multiple fields. stdout_lines is one of the default fields you can expect from a module's response.

Not all fields are available from all modules, for example for a module which doesn't return anything to the standard out you wouldn't expect anything in the stdout or stdout_lines values, however the msg field might be filled in this case. Also there are some modules where you might find something in a non-standard variable, for these you can try to consult the module's documentation for these non-standard return values.

Alternatively you can increase the verbosity level of ansible-playbook. You can choose between different verbosity levels: -v, -vvv and -vvvv. For example when running the playbook with verbosity (-vvv) you get this:

PLAY [localhost] ***************************************************************

TASK [command] *****************************************************************
(...)
changed: [localhost] => {
    "changed": true,
    "cmd": "ls",
    "delta": "0:00:00.007621",
    "end": "2017-02-17 23:04:41.912570",
    "invocation": {
        "module_args": {
            "_raw_params": "ls",
            "_uses_shell": true,
            "chdir": null,
            "creates": null,
            "executable": null,
            "removes": null,
            "warn": true
        },
        "module_name": "command"
    },
    "rc": 0,
    "start": "2017-02-17 23:04:41.904949",
    "stderr": "",
    "stdout": "play.retry\nplay.yml",
    "stdout_lines": [
        "play.retry",
        "play.yml"
    ],
    "warnings": []
}

As you can see this will print out the response of each of the modules, and all of the fields available. You can see that the stdout_lines is available, and its contents are what we expect.

To answer your main question about the jenkins_script module, if you check its documentation, you can see that it returns the output in the output field, so you might want to try the following:

tasks:
  - jenkins_script:
      script: (...)
    register: jenkins_result

  - debug:
      var: jenkins_result.output

window.close and self.close do not close the window in Chrome

I found a new way that works for me perfetly

var win = window.open("about:blank", "_self");
win.close();

C# ASP.NET MVC Return to Previous Page

For ASP.NET Core You can use asp-route-* attribute:

<form asp-action="Login" asp-route-previous="@Model.ReturnUrl">

An example: Imagine that you have a Vehicle Controller with actions

Index

Details

Edit

and you can edit any vehicle from Index or from Details, so if you clicked edit from index you must return to index after edit and if you clicked edit from details you must return to details after edit.

//In your viewmodel add the ReturnUrl Property
public class VehicleViewModel
{
     ..............
     ..............
     public string ReturnUrl {get;set;}
}



Details.cshtml
<a asp-action="Edit" asp-route-previous="Details" asp-route-id="@Model.CarId">Edit</a>

Index.cshtml
<a asp-action="Edit" asp-route-previous="Index" asp-route-id="@item.CarId">Edit</a>

Edit.cshtml
<form asp-action="Edit" asp-route-previous="@Model.ReturnUrl" class="form-horizontal">
        <div class="box-footer">
            <a asp-action="@Model.ReturnUrl" class="btn btn-default">Back to List</a>
            <button type="submit" value="Save" class="btn btn-warning pull-right">Save</button>
        </div>
    </form>

In your controller:

// GET: Vehicle/Edit/5
    public ActionResult Edit(int id,string previous)
    {
            var model = this.UnitOfWork.CarsRepository.GetAllByCarId(id).FirstOrDefault();
            var viewModel = this.Mapper.Map<VehicleViewModel>(model);//if you using automapper
    //or by this code if you are not use automapper
    var viewModel = new VehicleViewModel();

    if (!string.IsNullOrWhiteSpace(previous)
                viewModel.ReturnUrl = previous;
            else
                viewModel.ReturnUrl = "Index";
            return View(viewModel);
        }



[HttpPost]
    public IActionResult Edit(VehicleViewModel model, string previous)
    {
            if (!string.IsNullOrWhiteSpace(previous))
                model.ReturnUrl = previous;
            else
                model.ReturnUrl = "Index";
            ............. 
            .............
            return RedirectToAction(model.ReturnUrl);
    }

Moving matplotlib legend outside of the axis makes it cutoff by the figure box

Sorry EMS, but I actually just got another response from the matplotlib mailling list (Thanks goes out to Benjamin Root).

The code I am looking for is adjusting the savefig call to:

fig.savefig('samplefigure', bbox_extra_artists=(lgd,), bbox_inches='tight')
#Note that the bbox_extra_artists must be an iterable

This is apparently similar to calling tight_layout, but instead you allow savefig to consider extra artists in the calculation. This did in fact resize the figure box as desired.

import matplotlib.pyplot as plt
import numpy as np

plt.gcf().clear()
x = np.arange(-2*np.pi, 2*np.pi, 0.1)
fig = plt.figure(1)
ax = fig.add_subplot(111)
ax.plot(x, np.sin(x), label='Sine')
ax.plot(x, np.cos(x), label='Cosine')
ax.plot(x, np.arctan(x), label='Inverse tan')
handles, labels = ax.get_legend_handles_labels()
lgd = ax.legend(handles, labels, loc='upper center', bbox_to_anchor=(0.5,-0.1))
text = ax.text(-0.2,1.05, "Aribitrary text", transform=ax.transAxes)
ax.set_title("Trigonometry")
ax.grid('on')
fig.savefig('samplefigure', bbox_extra_artists=(lgd,text), bbox_inches='tight')

This produces:

[edit] The intent of this question was to completely avoid the use of arbitrary coordinate placements of arbitrary text as was the traditional solution to these problems. Despite this, numerous edits recently have insisted on putting these in, often in ways that led to the code raising an error. I have now fixed the issues and tidied the arbitrary text to show how these are also considered within the bbox_extra_artists algorithm.

How to convert data.frame column from Factor to numeric

This is FAQ 7.10. Others have shown how to apply this to a single column in a data frame, or to multiple columns in a data frame. But this is really treating the symptom, not curing the cause.

A better approach is to use the colClasses argument to read.table and related functions to tell R that the column should be numeric so that it never creates a factor and creates numeric. This will put in NA for any values that do not convert to numeric.

Another better option is to figure out why R does not recognize the column as numeric (usually a non numeric character somewhere in that column) and fix the original data so that it is read in properly without needing to create NAs.

Best is a combination of the last 2, make sure the data is correct before reading it in and specify colClasses so R does not need to guess (this can speed up reading as well).

How do I create a link using javascript?

Create links using JavaScript:

<script language="javascript">
<!--
document.write("<a href=\"www.example.com\">");
document.write("Your Title");
document.write("</a>");
//-->
</script>

OR

<script type="text/javascript">
document.write('Your Title'.link('http://www.example.com'));
</script>

OR

<script type="text/javascript">
newlink = document.createElement('a');
newlink.innerHTML = 'Google';
newlink.setAttribute('title', 'Google');
newlink.setAttribute('href', 'http://google.com');
document.body.appendChild(newlink);
</script>

Reading data from DataGridView in C#

Code Example : Reading data from DataGridView and storing it in an array

int[,] n = new int[3, 19];
for (int i = 0; i < (StartDataView.Rows.Count - 1); i++)
{
    for (int j = 0; j < StartDataView.Columns.Count; j++)
    {
        if(this.StartDataView.Rows[i].Cells[j].Value.ToString() != string.Empty)
        {
            try
            {
                n[i, j] = int.Parse(this.StartDataView.Rows[i].Cells[j].Value.ToString());
            }
            catch (Exception Ee)
            { //get exception of "null"
                MessageBox.Show(Ee.ToString());
            }
        }
    }
}

java: run a function after a specific number of seconds

All other unswers require to run your code inside a new thread. In some simple use cases you may just want to wait a bit and continue execution within the same thread/flow.

Code below demonstrates that technique. Keep in mind this is similar to what java.util.Timer does under the hood but more lightweight.

import java.util.concurrent.TimeUnit;
public class DelaySample {
    public static void main(String[] args) {
       DelayUtil d = new DelayUtil();
       System.out.println("started:"+ new Date());
       d.delay(500);
       System.out.println("half second after:"+ new Date());
       d.delay(1, TimeUnit.MINUTES); 
       System.out.println("1 minute after:"+ new Date());
    }
}

DelayUtil Implementation

import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;

public class DelayUtil {
    /** 
    *  Delays the current thread execution. 
    *  The thread loses ownership of any monitors. 
    *  Quits immediately if the thread is interrupted
    *  
    * @param duration the time duration in milliseconds
    */
   public void delay(final long durationInMillis) {
      delay(durationInMillis, TimeUnit.MILLISECONDS);
   }

   /** 
    * @param duration the time duration in the given {@code sourceUnit}
    * @param unit
    */
    public void delay(final long duration, final TimeUnit unit) {
        long currentTime = System.currentTimeMillis();
        long deadline = currentTime+unit.toMillis(duration);
        ReentrantLock lock = new ReentrantLock();
        Condition waitCondition = lock.newCondition();

        while ((deadline-currentTime)>0) {
            try {
                lock.lockInterruptibly();    
                waitCondition.await(deadline-currentTime, TimeUnit.MILLISECONDS);
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
                return;
            } finally {
                lock.unlock();
            }
            currentTime = System.currentTimeMillis();
        }
    }
}

Passing environment-dependent variables in webpack

I'm not a huge fan of...

new webpack.DefinePlugin({
  'process.env': envVars
}),

...as it does not provides any type of security. instead, you end up boosting your secret stuff, unless you add a webpack to gitignore ??? there is a better solution.

Basically with this config once you compile your code all the process env variables will be removed from the entire code, there is not going to be a single process.env.VAR up thanks to the babel plugin transform-inline-environment-variables PS if you do not want to end up with a whole bunch of undefines, make sure you call the env.js before webpack calls babel-loader, that's why it is the first thing webpack calls. the array of vars in babel.config.js file must match the object on env.js. now there is only one mow thing to do. add a .env file put all your env variables there, the file must be at the root of the project or feel free to add it where ever u want, just make sure to set the same location on the env.js file and also add it to gitignore

const dotFiles = ['.env'].filter(Boolean);

if (existsSync(dotFiles)) {
    require("dotenv-expand")(require("dotenv").config((dotFiles)));
}

If you want to see the whole babel + webpack + ts get it from heaw https://github.com/EnetoJara/Node-typescript-babel-webpack.git

and same logic applies to react and all the other

config
---webpack.js
---env.js
src
---source code world
.env
bunch of dotFiles

env.js

"use strict";
/***
I took the main idea from CRA, but mine is more cooler xD
*/
const {realpathSync, existsSync} = require('fs');
const {resolve, isAbsolute, delimiter} = require('path');

const NODE_ENV = process.env.NODE_ENV || "development";

const appDirectory = realpathSync(process.cwd());

if (typeof NODE_ENV !== "string") {
    throw new Error("falle and stuff");
}

const dotFiles = ['.env'].filter(Boolean);

if (existsSync(dotFiles)) {
    require("dotenv-expand")(require("dotenv").config((dotFiles)));
}

process.env.NODE_PATH = (process.env.NODE_PATH || "")
    .split(delimiter)
    .filter(folder => folder && isAbsolute(folder))
    .map(folder => resolve(appDirectory, folder))
    .join(delimiter);

const ENETO_APP = /^ENETO_APP_/i;

module.exports = (function () {
    const raw = Object.keys ( process.env )
        .filter ( key => ENETO_APP.test ( key ) )
        .reduce ( ( env, key ) => {
                env[ key ] = process.env[ key ];
                return env;
            },
            {
                BABEL_ENV: process.env.ENETO_APP_BABEL_ENV,
                ENETO_APP_DB_NAME: process.env.ENETO_APP_DB_NAME,
                ENETO_APP_DB_PASSWORD: process.env.ENETO_APP_DB_PASSWORD,
                ENETO_APP_DB_USER: process.env.ENETO_APP_DB_USER,
                GENERATE_SOURCEMAP: process.env.ENETO_APP_GENERATE_SOURCEMAP,
                NODE_ENV: process.env.ENETO_APP_NODE_ENV,
                PORT: process.env.ENETO_APP_PORT,
                PUBLIC_URL: "/"
            } );

    const stringyField = {
        "process.env": Object.keys(raw).reduce((env, key)=> {
            env[key]=JSON.stringify(raw[key]);
            return env;
        },{}),

    };

    return {
        raw, stringyField
    }
})();

webpack file with no plugins troll

"use strict";

require("core-js");
require("./env.js");

const path = require("path");
const nodeExternals = require("webpack-node-externals");

module.exports = env => {
    return {
        devtool: "source-map",
        entry: path.join(__dirname, '../src/dev.ts'),
        externals: [nodeExternals()],
        module: {
            rules: [
                {
                    exclude: /node_modules/,
                    test: /\.ts$/,
                    use: [
                        {
                            loader: "babel-loader",
                        },
                        {
                            loader: "ts-loader"
                        }
                    ],
                },
                {
                    test: /\.(png|jpg|gif)$/,
                    use: [
                        {
                            loader: "file-loader",
                        },
                    ],
                },
            ],
        },
        node: {
            __dirname: false,
            __filename: false,
        },
        optimization: {
            splitChunks: {
                automaticNameDelimiter: "_",
                cacheGroups: {
                    vendor: {
                        chunks: "initial",
                        minChunks: 2,
                        name: "vendor",
                        test: /[\\/]node_modules[\\/]/,
                    },
                },
            },
        },
        output: {
            chunkFilename: "main.chunk.js",
            filename: "name-bundle.js",
            libraryTarget: "commonjs2",
        },
        plugins: [],
        resolve: {
            extensions: ['.ts', '.js']
        }   ,
        target: "node"
    };
};

babel.config.js

module.exports = api => {

    api.cache(() => process.env.NODE_ENV);

    return {

        plugins: [
            ["@babel/plugin-proposal-decorators", { legacy: true }],
            ["@babel/plugin-transform-classes", {loose: true}],
            ["@babel/plugin-external-helpers"],
            ["@babel/plugin-transform-runtime"],
            ["@babel/plugin-transform-modules-commonjs"],
            ["transform-member-expression-literals"],
            ["transform-property-literals"],
            ["@babel/plugin-transform-reserved-words"],
            ["@babel/plugin-transform-property-mutators"],
            ["@babel/plugin-transform-arrow-functions"],
            ["@babel/plugin-transform-block-scoped-functions"],
            [
                "@babel/plugin-transform-async-to-generator",
                {
                    method: "coroutine",
                    module: "bluebird",
                },
            ],
            ["@babel/plugin-proposal-async-generator-functions"],
            ["@babel/plugin-transform-block-scoping"],
            ["@babel/plugin-transform-computed-properties"],
            ["@babel/plugin-transform-destructuring"],
            ["@babel/plugin-transform-duplicate-keys"],
            ["@babel/plugin-transform-for-of"],
            ["@babel/plugin-transform-function-name"],
            ["@babel/plugin-transform-literals"],
            ["@babel/plugin-transform-object-super"],
            ["@babel/plugin-transform-shorthand-properties"],
            ["@babel/plugin-transform-spread"],
            ["@babel/plugin-transform-template-literals"],
            ["@babel/plugin-transform-exponentiation-operator"],
            ["@babel/plugin-proposal-object-rest-spread"],
            ["@babel/plugin-proposal-do-expressions"],
            ["@babel/plugin-proposal-export-default-from"],
            ["@babel/plugin-proposal-export-namespace-from"],
            ["@babel/plugin-proposal-logical-assignment-operators"],
            ["@babel/plugin-proposal-throw-expressions"],
            [
                "transform-inline-environment-variables",
                {
                    include: [
                        "ENETO_APP_PORT",
                        "ENETO_APP_NODE_ENV",
                        "ENETO_APP_BABEL_ENV",
                        "ENETO_APP_DB_NAME",
                        "ENETO_APP_DB_USER",
                        "ENETO_APP_DB_PASSWORD",
                    ],
                },
            ],
        ],
        presets: [["@babel/preset-env",{
            targets: {
                node: "current",
                esmodules: true
            },
            useBuiltIns: 'entry',
            corejs: 2,
            modules: "cjs"
        }],"@babel/preset-typescript"],
    };
};

How to edit one specific row in Microsoft SQL Server Management Studio 2008?

Use the "Edit top 200" option, then click on "Show SQL panel", modify your query with your WHERE clause, and execute the query. You'll be able to edit the results.

Package php5 have no installation candidate (Ubuntu 16.04)

If you just want to install PHP no matter what version it is, try PHP7

sudo apt-get install php7.0 php7.0-mcrypt

Is there a way to get element by XPath using JavaScript in Selenium WebDriver?

For something like $x from chrome command line api (to select multiple elements) try:

var xpath = function(xpathToExecute){
  var result = [];
  var nodesSnapshot = document.evaluate(xpathToExecute, document, null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null );
  for ( var i=0 ; i < nodesSnapshot.snapshotLength; i++ ){
    result.push( nodesSnapshot.snapshotItem(i) );
  }
  return result;
}

This MDN overview helped: https://developer.mozilla.org/en-US/docs/Introduction_to_using_XPath_in_JavaScript

Missing include "bits/c++config.h" when cross compiling 64 bit program on 32 bit in Ubuntu

From my experience, sudo apt-get install gcc-multilib g++-multilib helps. But my another issue is that I FORGET to clean the directory so I still get the same error. It is the first time to use clang or cmake. So I just delete my original directory and re-compile and it works. Hope it helps someone like me.

Stop Visual Studio from launching a new browser window when starting debug?

Joao Costa answer also holds true for .Net core 2 projects.

launchsettings.json --> "launchBrowser": false

"profiles": {
    "IIS Express": {
      "commandName": "IISExpress",
      "launchBrowser": false,
      "environmentVariables": {
        "Hosting:Environment": "Development"
      }
    }
}

How do I implement interfaces in python?

Something like this (might not work as I don't have Python around):

class IInterface:
    def show(self): raise NotImplementedError

class MyClass(IInterface):
    def show(self): print "Hello World!"

How to rename a file using svn?

You can do it by following 3 steps:

 - svn rm old_file_name
 - svn add new_file_name
 - svn commit

Multiple conditions with CASE statements

It's not a cut and paste. The CASE expression must return a value, and you are returning a string containing SQL (which is technically a value but of a wrong type). This is what you wanted to write, I think:

SELECT * FROM [Purchasing].[Vendor] WHERE  
CASE
  WHEN @url IS null OR @url = '' OR @url = 'ALL'
    THEN PurchasingWebServiceURL LIKE '%'
  WHEN @url = 'blank'
    THEN PurchasingWebServiceURL = ''
  WHEN @url = 'fail'
    THEN PurchasingWebServiceURL NOT LIKE '%treyresearch%'
  ELSE PurchasingWebServiceURL = '%' + @url + '%' 
END

I also suspect that this might not work in some dialects, but can't test now (Oracle, I'm looking at you), due to not having booleans.

However, since @url is not dependent on the table values, why not make three different queries, and choose which to evaluate based on your parameter?

How does JPA orphanRemoval=true differ from the ON DELETE CASCADE DML clause

orphan removal has the same effect as ON DELETE CASCADE in the following scenario:- Lets say we have a simple many to one relationship between student entity and a guide entity, where many students can be mapped to the same guide and in database we have a foreign key relation between Student and Guide table such that student table has id_guide as FK.

    @Entity
    @Table(name = "student", catalog = "helloworld")
    public class Student implements java.io.Serializable {
     @Id
     @GeneratedValue(strategy = IDENTITY)
     @Column(name = "id")
     private Integer id;

    @ManyToOne(cascade={CascadeType.PERSIST,CascadeType.REMOVE})
    @JoinColumn(name = "id_guide")
    private Guide guide;

// The parent entity

    @Entity
    @Table(name = "guide", catalog = "helloworld")
    public class Guide implements java.io.Serializable {

/**
 * 
 */
private static final long serialVersionUID = 9017118664546491038L;

@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "id", unique = true, nullable = false)
private Integer id;

@Column(name = "name", length = 45)
private String name;

@Column(name = "salary", length = 45)
private String salary;


 @OneToMany(mappedBy = "guide", orphanRemoval=true) 
 private Set<Student> students = new  HashSet<Student>(0);

In this scenario, the relationship is such that student entity is the owner of the relationship and as such we need to save the student entity in order to persist the whole object graph e.g.

    Guide guide = new Guide("John", "$1500");
    Student s1 = new Student(guide, "Roy","ECE");
    Student s2 = new Student(guide, "Nick", "ECE");
    em.persist(s1);
    em.persist(s2);

Here we are mapping the same guide with two different student objects and since the CASCADE.PERSIST is used , the object graph will be saved as below in the database table(MySql in my case)

STUDENT table:-

ID Name Dept Id_Guide

1     Roy     ECE    1

2    Nick    ECE    1

GUIDE Table:-

ID NAME Salary

1    John     $1500

and Now if I want to remove one of the students, using

      Student student1 = em.find(Student.class,1);
      em.remove(student1);

and when a student record is removed the corresponding guide record should also be removed, that's where CASCADE.REMOVE attribute in the Student entity comes into picture and what it does is ;it removes the student with identifier 1 as well the corresponding guide object(identifier 1). But in this example, there is one more student object which is mapped to the same guide record and unless we use the orphanRemoval=true attribute in the Guide Entity , the remove code above will not work.

Setting Oracle 11g Session Timeout

That's generally controlled by the profile associated with the user Tomcat is connecting as.

SQL> SELECT PROFILE, LIMIT FROM DBA_PROFILES WHERE RESOURCE_NAME = 'IDLE_TIME';

PROFILE                        LIMIT
------------------------------ ----------------------------------------
DEFAULT                        UNLIMITED

SQL> SELECT PROFILE FROM DBA_USERS WHERE USERNAME = USER;

PROFILE
------------------------------
DEFAULT

So the user I'm connected to has unlimited idle time - no time out.

EXCEL Multiple Ranges - need different answers for each range

Nested if's in Excel Are ugly:

=If(G2 < 1, .1, IF(G2 < 5,.15,if(G2 < 15,.2,if(G2 < 30,.5,if(G2 < 100,.1,1.3)))))

That should cover it.

Convert seconds into days, hours, minutes and seconds

This can be achieved with DateTime class

Function:

function secondsToTime($seconds) {
    $dtF = new \DateTime('@0');
    $dtT = new \DateTime("@$seconds");
    return $dtF->diff($dtT)->format('%a days, %h hours, %i minutes and %s seconds');
}

Use:

echo secondsToTime(1640467);
# 18 days, 23 hours, 41 minutes and 7 seconds

demo

How can I call PHP functions by JavaScript?

use document.write for example,

<script>
  document.write(' <?php add(1,2); ?> ');
  document.write(' <?php milt(1,2); ?> ');
  document.write(' <?php divide(1,2); ?> ');
</script>

Is there a query language for JSON?


I've just finished a releaseable version of a clientside JS-lib (defiant.js) that does what you're looking for. With defiant.js, you can query a JSON structure with the XPath expressions you're familiar with (no new syntax expressions as in JSONPath).

Example of how it works (see it in browser here http://defiantjs.com/defiant.js/demo/sum.avg.htm):

var data = [
       { "x": 2, "y": 0 },
       { "x": 3, "y": 1 },
       { "x": 4, "y": 1 },
       { "x": 2, "y": 1 }
    ],
    res = JSON.search( data, '//*[ y > 0 ]' );

console.log( res.sum('x') );
// 9
console.log( res.avg('x') );
// 3
console.log( res.min('x') );
// 2
console.log( res.max('x') );
// 4

As you can see, DefiantJS extends the global object JSON with a search function and the returned array is delivered with aggregate functions. DefiantJS contains a few other functionalities but those are out of the scope for this subject. Anywho, you can test the lib with a clientside XPath Evaluator. I think people not familiar with XPath will find this evaluator useful.
http://defiantjs.com/#xpath_evaluator

More information about defiant.js
http://defiantjs.com/
https://github.com/hbi99/defiant.js

I hope you find it useful... Regards

How do I limit the number of rows returned by an Oracle query after ordering?

If you are not on Oracle 12C, you can use TOP N query like below.

SELECT *
 FROM
   ( SELECT rownum rnum
          , a.*
       FROM sometable a 
   ORDER BY name
   )
WHERE rnum BETWEEN 10 AND 20;

You can even move this from clause in with clause as follows

WITH b AS
( SELECT rownum rnum
      , a.* 
   FROM sometable a ORDER BY name
) 
SELECT * FROM b 
WHERE rnum BETWEEN 10 AND 20;

Here actually we are creating a inline view and renaming rownum as rnum. You can use rnum in main query as filter criteria.

Select rows from a data frame based on values in a vector

Similar to above, using filter from dplyr:

filter(df, fct %in% vc)

Why doesn't indexOf work on an array IE8?

The problem

IE<=8 simply doesn't have an indexOf() method for arrays.


The solution

If you need indexOf in IE<=8, you should consider using the following polyfill, which is recommended at the MDN :

if (!Array.prototype.indexOf) {
    Array.prototype.indexOf = function(searchElement, fromIndex) {
        var k;
        if (this == null) {
            throw new TypeError('"this" is null or not defined');
        }
        var o = Object(this);
        var len = o.length >>> 0;
        if (len === 0) {
            return -1;
        }
        var n = +fromIndex || 0;
        if (Math.abs(n) === Infinity) {
            n = 0;
        }
        if (n >= len) {
            return -1;
        }
        k = Math.max(n >= 0 ? n : len - Math.abs(n), 0);
        while (k < len) {
            if (k in o && o[k] === searchElement) {
                return k;
            }
            k++;
        }
        return -1;
    };
}

Minified :

Array.prototype.indexOf||(Array.prototype.indexOf=function(r,t){var n;if(null==this)throw new TypeError('"this" is null or not defined');var e=Object(this),i=e.length>>>0;if(0===i)return-1;var a=+t||0;if(Math.abs(a)===1/0&&(a=0),a>=i)return-1;for(n=Math.max(a>=0?a:i-Math.abs(a),0);i>n;){if(n in e&&e[n]===r)return n;n++}return-1});

How to Make Laravel Eloquent "IN" Query?

If you are using Query builder then you may use a blow

DB::table(Newsletter Subscription)
->select('*')
->whereIn('id', $send_users_list)
->get()

If you are working with Eloquent then you can use as below

$sendUsersList = Newsletter Subscription:: select ('*')
                ->whereIn('id', $send_users_list)
                ->get();

Making HTTP Requests using Chrome Developer tools

Keeping it simple, if you want the request to use the same browsing context as the page you are already looking at then in the Chrome console just do:

window.location="https://www.example.com";

Git ignore file for Xcode projects

For Xcode 4 I also add:

YourProjectName.xcodeproj/xcuserdata/*
YourProjectName.xcodeproj/project.xcworkspace/xcuserdata/*

How to check postgres user and password?

You may change the pg_hba.conf and then reload the postgresql. something in the pg_hba.conf may be like below:

# "local" is for Unix domain socket connections only
local   all             all                                     trust
# IPv4 local connections:
host    all             all             127.0.0.1/32            trust

then you change your user to postgresql, you may login successfully.

su postgresql

C#: How do you edit items and subitems in a listview?

Sorry, don't have enough rep, or would have commented on CraigTP's answer.

I found the solution from the 1st link - C# Editable ListView, quite easy to use. The general idea is to:

  • identify the SubItem that was selected and overlay a TextBox with the SubItem's text over the SubItem
  • give this TextBox focus
  • change SubItem's text to that of TextBox's when TextBox loses focus

What a workaround for a seemingly simple operation :-|

How can I introduce multiple conditions in LIKE operator?

I also had the same requirement where I didn't have choice to pass like operator multiple times by either doing an OR or writing union query.

This worked for me in Oracle 11g:

REGEXP_LIKE (column, 'ABC.*|XYZ.*|PQR.*'); 

Remove the newline character in a list read from a file

You could actually put the newlines to good use by reading the entire file into memory as a single long string and then use them to split that into the list of grades.

with open("grades.dat") as input:
    grades = [line.split(",") for line in input.read().splitlines()]
etc...

How to prevent 'query timeout expired'? (SQLNCLI11 error '80040e31')

Turns out that the post (or rather the whole table) was locked by the very same connection that I tried to update the post with.

I had a opened record set of the post that was created by:

Set RecSet = Conn.Execute()

This type of recordset is supposed to be read-only and when I was using MS Access as database it did not lock anything. But apparently this type of record set did lock something on MS SQL Server 2012 because when I added these lines of code before executing the UPDATE SQL statement...

RecSet.Close
Set RecSet = Nothing

...everything worked just fine.

So bottom line is to be careful with opened record sets - even if they are read-only they could lock your table from updates.

Case insensitive access for generic dictionary

There is much simpler way:

using System;
using System.Collections.Generic;
....
var caseInsensitiveDictionary = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);

Interpreting segfault messages

This is a segfault due to following a null pointer trying to find code to run (that is, during an instruction fetch).

If this were a program, not a shared library

Run addr2line -e yourSegfaultingProgram 00007f9bebcca90d (and repeat for the other instruction pointer values given) to see where the error is happening. Better, get a debug-instrumented build, and reproduce the problem under a debugger such as gdb.

Since it's a shared library

You're hosed, unfortunately; it's not possible to know where the libraries were placed in memory by the dynamic linker after-the-fact. Reproduce the problem under gdb.

What the error means

Here's the breakdown of the fields:

  • address (after the at) - the location in memory the code is trying to access (it's likely that 10 and 11 are offsets from a pointer we expect to be set to a valid value but which is instead pointing to 0)
  • ip - instruction pointer, ie. where the code which is trying to do this lives
  • sp - stack pointer
  • error - An error code for page faults; see below for what this means on x86.

    /*
     * Page fault error code bits:
     *
     *   bit 0 ==    0: no page found       1: protection fault
     *   bit 1 ==    0: read access         1: write access
     *   bit 2 ==    0: kernel-mode access  1: user-mode access
     *   bit 3 ==                           1: use of reserved bit detected
     *   bit 4 ==                           1: fault was an instruction fetch
     */
    

wait until all threads finish their work in java

You can join to the threads. The join blocks until the thread completes.

for (Thread thread : threads) {
    thread.join();
}

Note that join throws an InterruptedException. You'll have to decide what to do if that happens (e.g. try to cancel the other threads to prevent unnecessary work being done).

Named parameters in JDBC

JDBC does not support named parameters. Unless you are bound to using plain JDBC (which causes pain, let me tell you that) I would suggest to use Springs Excellent JDBCTemplate which can be used without the whole IoC Container.

NamedParameterJDBCTemplate supports named parameters, you can use them like that:

 NamedParameterJdbcTemplate jdbcTemplate = new NamedParameterJdbcTemplate(dataSource);

 MapSqlParameterSource paramSource = new MapSqlParameterSource();
 paramSource.addValue("name", name);
 paramSource.addValue("city", city);
 jdbcTemplate.queryForRowSet("SELECT * FROM customers WHERE name = :name AND city = :city", paramSource);

Convert php array to Javascript

For a multidimensional array in PHP4 you can use the following addition to the code posted by Udo G:

function js_str($s) {
   return '"'.addcslashes($s, "\0..\37\"\\").'"';
}

function js_array($array, $keys_array) {
  foreach ($array as $key => $value) {
    $new_keys_array = $keys_array;
    $new_keys_array[] = $key;
    if(is_array($value)) {          
      echo 'javascript_array';
      foreach($new_keys_array as $key) {
        echo '["'.$key.'"]';
      }
      echo ' = new Array();';

      js_array($value, $new_keys_array);
    } else {
      echo 'javascript_array';
      foreach($new_keys_array as $key) {
        echo '["'.$key.'"]';
      }
      echo ' = '.js_str($value).";";                        
    }
  } 
}

echo 'var javascript_array = new Array();';
js_array($php_array, array());

If condition inside of map() React

You are using both ternary operator and if condition, use any one.

By ternary operator:

.map(id => {
    return this.props.schema.collectionName.length < 0 ?
        <Expandable>
            <ObjectDisplay
                key={id}
                parentDocumentId={id}
                schema={schema[this.props.schema.collectionName]}
                value={this.props.collection.documents[id]}
            />
        </Expandable>
    :
        <h1>hejsan</h1>
}

By if condition:

.map(id => {
    if(this.props.schema.collectionName.length < 0)
        return <Expandable>
                  <ObjectDisplay
                      key={id}
                      parentDocumentId={id}
                      schema={schema[this.props.schema.collectionName]}
                      value={this.props.collection.documents[id]}
                  />
              </Expandable>
    return <h1>hejsan</h1>
}

Print array elements on separate lines in Bash?

Try doing this :

$ printf '%s\n' "${my_array[@]}"

The difference between $@ and $*:

  • Unquoted, the results are unspecified. In Bash, both expand to separate args and then wordsplit and globbed.

  • Quoted, "$@" expands each element as a separate argument, while "$*" expands to the args merged into one argument: "$1c$2c..." (where c is the first char of IFS).

You almost always want "$@". Same goes for "${arr[@]}".

Always quote them!

How stable is the git plugin for eclipse?

I'm using if for day-to-day work and I find it stable. Lately the plugin has made good progress and has added:

  • merge support, including a in-Eclipse merge tool;
  • a basic synchronise view;
  • reading of .git/info/exclude and .gitignore files.
  • rebasing;
  • streamlined commands for pushing and pulling;
  • cherry-picking.

Git repositories view

Be sure to skim the EGit User Guide for a good overview of the current functionality.

I find that I only need to drop to the comand line for interactive rebases.

As an official Eclipse project I am confident that EGit will receive all the main features of the command-line client.

How to comment/uncomment in HTML code

My view templates are generally .php files. This is what I would be using for now.

<?php // Some comment here ?>

The solution is quite similar to what @Robert suggested, works for me. Is not very clean I guess.

Can someone explain mappedBy in JPA and Hibernate?

Table relationship vs. entity relationship

In a relational database system, a one-to-many table relationship looks as follows:

one-to-many table relationship

Note that the relationship is based on the Foreign Key column (e.g., post_id) in the child table.

So, there is a single source of truth when it comes to managing a one-to-many table relationship.

Now, if you take a bidirectional entity relationship that maps on the one-to-many table relationship we saw previously:

Bidirectional One-To-Many entity association

If you take a look at the diagram above, you can see that there are two ways to manage this relationship.

In the Post entity, you have the comments collection:

@OneToMany(
    mappedBy = "post",
    cascade = CascadeType.ALL,
    orphanRemoval = true
)
private List<PostComment> comments = new ArrayList<>();

And, in the PostComment, the post association is mapped as follows:

@ManyToOne(
    fetch = FetchType.LAZY
)
@JoinColumn(name = "post_id")
private Post post;

Because there are two ways to represent the Foreign Key column, you must define which is the source of truth when it comes to translating the association state change into its equivalent Foreign Key column value modification.

MappedBy

The mappedBy attribute tells that the @ManyToOne side is in charge of managing the Foreign Key column, and the collection is used only to fetch the child entities and to cascade parent entity state changes to children (e.g., removing the parent should also remove the child entities).

Synchronize both sides of a bidirectional association

Now, even if you defined the mappedBy attribute and the child-side @ManyToOne association manages the Foreign Key column, you still need to synchronize both sides of the bidirectional association.

The best way to do that is to add these two utility methods:

public void addComment(PostComment comment) {
    comments.add(comment);
    comment.setPost(this);
}

public void removeComment(PostComment comment) {
    comments.remove(comment);
    comment.setPost(null);
}

The addComment and removeComment methods ensure that both sides are synchronized. So, if we add a child entity, the child entity needs to point to the parent and the parent entity should have the child contained in the child collection.

check if a file is open in Python

if myfile.closed == False:
   print("File is still open ################")

How do you find the sum of all the numbers in an array in Java?

You can make your code look better like this:

public void someMethod(){
    List<Integer> numbers = new ArrayList<Integer>();
    numbers.addAll(db.findNumbers());
    ...
    System.out.println("Result is " + sumOfNumbers(numbers));
}

private int sumOfNumbers(List<Integer> numbers){
    int sum = 0;
    for (Integer i : numbers){
      sum += i;
    }
    return sum;
}

Process to convert simple Python script into Windows executable

You could create an installer for you EXE file by:
1. Press WinKey + R
2. Type "iexpress" (without quotes) into the run window
3. Complete the wizard for creating the installation program.
4. Distribute the completed EXE.

How to force Hibernate to return dates as java.util.Date instead of Timestamp?

Approaches 1 and 2 obviously don't work, because you get java.sql.Date objects, per JPA/Hibernate spec, and not java.util.Date. From approaches 3 and 4, I would rather choose the latter one, because it's more declarative, and will work with both field and getter annotations.

You have already laid out the solution 4 in your referenced blog post, as @tscho was kind to point out. Maybe defaultForType (see below) should give you the centralized solution you were looking for. Of course will will still need to differentiate between date (without time) and timestamp fields.

For future reference I will leave the summary of using your own Hibernate UserType here:

To make Hibernate give you java.util.Date instances, you can use the @Type and @TypeDef annotations to define a different mapping of your java.util.Date java types to and from the database.

See the examples in the core reference manual here.

  1. Implement a UserType to do the actual plumbing (conversion to/from java.util.Date), named e.g. TimestampAsJavaUtilDateType
  2. Add a @TypeDef annotation on one entity or in a package-info.java - both will be available globally for the session factory (see manual link above). You can use defaultForType to apply the type conversion on all mapped fields of type java.util.Date.

    @TypeDef
      name = "timestampAsJavaUtilDate",
      defaultForType = java.util.Date.class, /* applied globally */
      typeClass = TimestampAsJavaUtilDateType.class
    )
    
  3. Optionally, instead of defaultForType, you can annotate your fields/getters with @Type individually:

    @Entity
    public class MyEntity {
       [...]
       @Type(type="timestampAsJavaUtilDate")
       private java.util.Date myDate;
       [...]
    }
    

P.S. To suggest a totally different approach: we usually just don't compare Date objects using equals() anyway. Instead we use a utility class with methods to compare e.g. only the calendar date of two Date instances (or another resolution such as seconds), regardless of the exact implementation type. That as worked well for us.

Finding out the name of the original repository you cloned from in Git

git remote show origin -n | ruby -ne 'puts /^\s*Fetch.*(:|\/){1}([^\/]+\/[^\/]+).git/.match($_)[2] rescue nil'

It was tested with three different URL styles:

echo "Fetch URL: http://user@pass:gitservice.org:20080/owner/repo.git" | ruby -ne 'puts /^\s*Fetch.*(:|\/){1}([^\/]+\/[^\/]+).git/.match($_)[2] rescue nil'
echo "Fetch URL: Fetch URL: [email protected]:home1-oss/oss-build.git" | ruby -ne 'puts /^\s*Fetch.*(:|\/){1}([^\/]+\/[^\/]+).git/.match($_)[2] rescue nil'
echo "Fetch URL: https://github.com/owner/repo.git" | ruby -ne 'puts /^\s*Fetch.*(:|\/){1}([^\/]+\/[^\/]+).git/.match($_)[2] rescue nil'

Inline comments for Bash?

$(: ...) is a little less ugly, but still not good.

Check if current directory is a Git repository

Why not using exit codes? If a git repository exists in the current directory, then git branch and git tag commands return exit code of 0; otherwise, a non-zero exit code will be returned. This way, you can determine if a git repository exist or not. Simply, you can run:

git tag > /dev/null 2>&1 && [ $? -eq 0 ]

Advantage: Flexibe. It works for both bare and non-bare repositories, and in sh, zsh and bash.

Explanation

  1. git tag: Getting tags of the repository to determine if exists or not.
  2. > /dev/null 2>&1: Preventing from printing anything, including normal and error outputs.
  3. [ $? -eq 0 ]: Check if the previous command returned with exit code 0 or not. As you may know, every non-zero exit means something bad happened. $? gets the exit code of the previous command, and [, -eq and ] perform the comparison.

As an example, you can create a file named check-git-repo with the following contents, make it executable and run it:

#!/bin/sh

if git tag > /dev/null 2>&1 && [ $? -eq 0 ]; then
    echo "Repository exists!";
else
    echo "No repository here.";
fi

What does the Visual Studio "Any CPU" target mean?

"Any CPU" means that when the program is started, the .NET Framework will figure out, based on the OS bitness, whether to run your program in 32 bits or 64 bits.

There is a difference between x86 and Any CPU: on a x64 system, your executable compiled for X86 will run as a 32-bit executable.

As far as your suspicions go, just go to the Visual Studio 2008 command line and run the following.

dumpbin YourProgram.exe /headers

It will tell you the bitness of your program, plus a whole lot more.

Polymorphism vs Overriding vs Overloading

overriding is more like hiding an inherited method by declaring a method with the same name and signature as the upper level method (super method), this adds a polymorphic behaviour to the class . in other words the decision to choose wich level method to be called will be made at run time not on compile time . this leads to the concept of interface and implementation .

Split a python list into other "sublists" i.e smaller lists

chunks = [data[100*i:100*(i+1)] for i in range(len(data)/100 + 1)]

This is equivalent to the accepted answer. For example, shortening to batches of 10 for readability:

data = range(35)
print [data[x:x+10] for x in xrange(0, len(data), 10)]
print [data[10*i:10*(i+1)] for i in range(len(data)/10 + 1)]

Outputs:

[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [10, 11, 12, 13, 14, 15, 16, 17, 18, 19], [20, 21, 22, 23, 24, 25, 26, 27, 28, 29], [30, 31, 32, 33, 34]]
[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9], [10, 11, 12, 13, 14, 15, 16, 17, 18, 19], [20, 21, 22, 23, 24, 25, 26, 27, 28, 29], [30, 31, 32, 33, 34]]

Entity Framework code first unique column

In Entity Framework 6.1+ you can use this attribute on your model:

[Index(IsUnique=true)]

You can find it in this namespace:

using System.ComponentModel.DataAnnotations.Schema;

If your model field is a string, make sure it is not set to nvarchar(MAX) in SQL Server or you will see this error with Entity Framework Code First:

Column 'x' in table 'dbo.y' is of a type that is invalid for use as a key column in an index.

The reason is because of this:

SQL Server retains the 900-byte limit for the maximum total size of all index key columns."

(from: http://msdn.microsoft.com/en-us/library/ms191241.aspx )

You can solve this by setting a maximum string length on your model:

[StringLength(450)]

Your model will look like this now in EF CF 6.1+:

public class User
{
   public int UserId{get;set;}
   [StringLength(450)]
   [Index(IsUnique=true)]
   public string UserName{get;set;}
}

Update:

if you use Fluent:

  public class UserMap : EntityTypeConfiguration<User>
  {
    public UserMap()
    {
      // ....
      Property(x => x.Name).IsRequired().HasMaxLength(450).HasColumnAnnotation("Index", new IndexAnnotation(new[] { new IndexAttribute("Index") { IsUnique = true } }));
    }
  }

and use in your modelBuilder:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
  // ...
  modelBuilder.Configurations.Add(new UserMap());
  // ...
}

Update 2

for EntityFrameworkCore see also this topic: https://github.com/aspnet/EntityFrameworkCore/issues/1698

Update 3

for EF6.2 see: https://github.com/aspnet/EntityFramework6/issues/274

Update 4

ASP.NET Core Mvc 2.2 with EF Core:

[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public Guid Unique { get; set; }

How to connect to LocalDB in Visual Studio Server Explorer?

Fix doesn't work.

Exactly as in the example illustration, all these steps only provide access to "system" databases, and no option to select existing user databases that you want to access.

The solution to access a local (not Express Edition) Microsoft SQL server instance resides on the SQL Server side:

  1. Open the Run dialog (WinKey + R)
  2. Type: "services.msc"
  3. Select SQL Server Browser
  4. Click Properties
  5. Change "disabled" to either "Manual" or "Automatic"
  6. When the "Start" service button gets enable, click on it.

Done! Now you can select your local SQL Server from the Server Name list in Connection Properties.

Way to go from recursion to iteration

Just killing time... A recursive function

void foo(Node* node)
{
    if(node == NULL)
       return;
    // Do something with node...
    foo(node->left);
    foo(node->right);
}

can be converted to

void foo(Node* node)
{
    if(node == NULL)
       return;

    // Do something with node...

    stack.push(node->right);
    stack.push(node->left);

    while(!stack.empty()) {
         node1 = stack.pop();
         if(node1 == NULL)
            continue;
         // Do something with node1...
         stack.push(node1->right);             
         stack.push(node1->left);
    }

}

MySQL COUNT DISTINCT

You need to use a group by clause.

SELECT  site_id, MAX(ts) as TIME, count(*) group by site_id

Find all files with name containing string

If the string is at the beginning of the name, you can do this

$ compgen -f .bash
.bashrc
.bash_profile
.bash_prompt

Any way to write a Windows .bat file to kill processes?

taskkill /f /im "devenv.exe"

this will forcibly kill the pid with the exe name "devenv.exe"

equivalent to -9 on the nix'y kill command

Max or Default?

int max = list.Any() ? list.Max(i => i.MyCounter) : 0;

If the list has any elements (ie. not empty), it will take the max of the MyCounter field, else will return 0.

I can't find my git.exe file in my Github folder

I found git here

C:\Users\<User>\AppData\Local\GitHubDesktop\app-0.5.8\resources\app\git\cmd\git.exe

You have to write file name (git.exe) in the end of path otherwise it will give an error=5enter image description here


Or you can check here also.

C:\Program Files\Git\bin\git.exe

enter image description here

Object of class DateTime could not be converted to string

Check to make sure there is a film release date; if the date is missing you will not be able to format on a non-object.

if ($info['Film_Release']){ //check if the date exists
   $dateFromDB = $info['Film_Release'];
   $newDate = DateTime::createFromFormat("l dS F Y", $dateFromDB);
   $newDate = $newDate->format('d/m/Y'); 
} else {
   $newDate = "none"; 
}

or

 $newDate = ($info['Film_Release']) ? DateTime::createFromFormat("l dS F Y", $info['Film_Release'])->format('d/m/Y'): "none" 

How to obtain the total numbers of rows from a CSV file in Python?

Use "list" to fit a more workably object.

You can then count, skip, mutate till your heart's desire:

list(fileObject) #list values

len(list(fileObject)) # get length of file lines

list(fileObject)[10:] # skip first 10 lines

How to break/exit from a each() function in JQuery?

You can use return false;

+----------------------------------------+
| JavaScript              | PHP          |
+-------------------------+--------------+
|                         |              |
| return false;           | break;       |
|                         |              |
| return true; or return; | continue;    |
+-------------------------+--------------+

Plot smooth line with PyPlot

Here is a simple solution for dates:

from scipy.interpolate import make_interp_spline
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.dates as dates
from datetime import datetime

data = {
    datetime(2016, 9, 26, 0, 0): 26060, datetime(2016, 9, 27, 0, 0): 23243,
    datetime(2016, 9, 28, 0, 0): 22534, datetime(2016, 9, 29, 0, 0): 22841,
    datetime(2016, 9, 30, 0, 0): 22441, datetime(2016, 10, 1, 0, 0): 23248 
}
#create data
date_np = np.array(list(data.keys()))
value_np = np.array(list(data.values()))
date_num = dates.date2num(date_np)
# smooth
date_num_smooth = np.linspace(date_num.min(), date_num.max(), 100) 
spl = make_interp_spline(date_num, value_np, k=3)
value_np_smooth = spl(date_num_smooth)
# print
plt.plot(date_np, value_np)
plt.plot(dates.num2date(date_num_smooth), value_np_smooth)
plt.show()

example

python list in sql query as parameter

placeholders= ', '.join("'{"+str(i)+"}'" for i in range(len(l)))
query="select name from students where id (%s)"%placeholders
query=query.format(*l)
cursor.execute(query)

This should solve your problem.

How to modify WooCommerce cart, checkout pages (main theme portion)

I've found this works well as a conditional within page.php that includes the WooCommerce cart and checkout screens.

!is_page(array('cart', 'checkout'))

Change the background color of CardView programmatically

The way it's set in the initialize method uses the protected RoundRectDrawable class, like so:

RoundRectDrawable backgroundDrawable = new RoundRectDrawable(backgroundColor, cardView.getRadius());
cardView.setBackgroundDrawable(backgroundDrawable);

It's not pretty, but you can extend that class. Something like:

package android.support.v7.widget;

public class MyRoundRectDrawable extends RoundRectDrawable {

    public MyRoundRectDrawable(int backgroundColor, float radius) {
        super(backgroundColor, radius);
    }

}

then:

final MyRoundRectDrawable backgroundDrawable = new MyRoundRectDrawable(bgColor,
            mCardView.getRadius());
mCardView.setBackgroundDrawable(backgroundDrawable);

EDIT

This won't give you the shadow on < API 21, so you'd have to do the same with RoundRectDrawableWithShadow.

There doesn't appear to be a better way to do this.

Firebase (FCM) how to get token

Try this. Why are you using RegistrationIntentService ?

public class FirebaseInstanceIDService extends FirebaseInstanceIdService {    
    @Override
    public void onTokenRefresh() {    
        String token = FirebaseInstanceId.getInstance().getToken();    
        registerToken(token);
    }

    private void registerToken(String token) {

    }
}

How do I print the content of httprequest request?

This should be more helpful for debug. Answer from @Juned Ahsan will not specify full URL and will not print multiple headers/parameters.

private String httpServletRequestToString(HttpServletRequest request) {
    StringBuilder sb = new StringBuilder();

    sb.append("Request Method = [" + request.getMethod() + "], ");
    sb.append("Request URL Path = [" + request.getRequestURL() + "], ");

    String headers =
        Collections.list(request.getHeaderNames()).stream()
            .map(headerName -> headerName + " : " + Collections.list(request.getHeaders(headerName)) )
            .collect(Collectors.joining(", "));

    if (headers.isEmpty()) {
        sb.append("Request headers: NONE,");
    } else {
        sb.append("Request headers: ["+headers+"],");
    }

    String parameters =
        Collections.list(request.getParameterNames()).stream()
            .map(p -> p + " : " + Arrays.asList( request.getParameterValues(p)) )
            .collect(Collectors.joining(", "));             

    if (parameters.isEmpty()) {
        sb.append("Request parameters: NONE.");
    } else {
        sb.append("Request parameters: [" + parameters + "].");
    }

    return sb.toString();
}

Credentials for the SQL Server Agent service are invalid

I've had this error as a result of trying to use a cloned VM that had the same SID as the domain. The two options to fix it were: sysprep (or rebuild) the database server OR dcpromo the DC down and back up to change the domain SID.

How to show only next line after the matched one?

I don't know of any way to do this with grep, but it is possible to use awk to achieve the same result:

awk '/blah/ {getline;print}' < logfile

How to copy Docker images from one host to another without using a repository

You may use sshfs:

$ sshfs user@ip:/<remote-path> <local-mount-path>
$ docker save <image-id> > <local-mount-path>/myImage.tar

How to set background color of a View

// set the background to green
v.setBackgroundColor(0x0000FF00 );
v.invalidate();

The code does not set the button to green. Instead, it makes the button totally invisible.

Explanation: the hex value of the color is wrong. With an Alpha value of zero, the color will be invisible.

The correct hex value is 0xFF00FF00 for full opacity green. Any Alpha value between 00 and FF would cause transparency.

How to add a custom CA Root certificate to the CA Store used by pip in Windows?

I think nt86's solution is the most appropriate because it leverages the underlying Windows infrastructure (certificate store). But it doesn't explain how to install python-certifi-win32 to start with since pip is non functional.

The trick is to use --trustedhost to install python-certifi-win32 and then after that, pip will automatically use the windows certificate store to load the certificate used by the proxy.

So in a nutshell, you should do:

pip install python-certifi-win32 -trustedhost pypi.org

and after that you should be good to go

What does .pack() do?

The pack() method is defined in Window class in Java and it sizes the frame so that all its contents are at or above their preferred sizes.

Why use Gradle instead of Ant or Maven?

I don't use Gradle in anger myself (just a toy project so far) [author means they have used Gradle on only a toy project so far, not that Gradle is a toy project - see comments], but I'd say that the reasons one would consider using it would be because of the frustrations of Ant and Maven.

In my experience Ant is often write-only (yes I know it is possible to write beautifully modular, elegant builds, but the fact is most people don't). For any non-trivial projects it becomes mind-bending, and takes great care to ensure that complex builds are truly portable. Its imperative nature can lead to replication of configuration between builds (though macros can help here).

Maven takes the opposite approach and expects you to completely integrate with the Maven lifecycle. Experienced Ant users find this particularly jarring as Maven removes many of the freedoms you have in Ant. For example there's a Sonatype blog that enumerates many of the Maven criticisms and their responses.

The Maven plugin mechanism allows for very powerful build configurations, and the inheritance model means you can define a small set of parent POMs encapsulating your build configurations for the whole enterprise and individual projects can inherit those configurations, leaving them lightweight. Maven configuration is very verbose (though Maven 3 promises to address this), and if you want to do anything that is "not the Maven way" you have to write a plugin or use the hacky Ant integration. Note I happen to like writing Maven plugins but appreciate that many will object to the effort involved.

Gradle promises to hit the sweet spot between Ant and Maven. It uses Ivy's approach for dependency resolution. It allows for convention over configuration but also includes Ant tasks as first class citizens. It also wisely allows you to use existing Maven/Ivy repositories.

So if you've hit and got stuck with any of the Ant/Maven pain points, it is probably worth trying Gradle out, though in my opinion it remains to be seen if you wouldn't just be trading known problems for unknown ones. The proof of the pudding is in the eating though so I would reserve judgment until the product is a little more mature and others have ironed out any kinks (they call it bleeding edge for a reason). I'll still be using it in my toy projects though, It's always good to be aware of the options.

Facebook Like-Button - hide count?

this worked for me:

.fb-like.fb_edge_widget_with_comment.fb_iframe_widget {
    height: 26px;
    overflow: hidden;
    width: 138px;
}

.NET HashTable Vs Dictionary - Can the Dictionary be as fast?

Another important difference is that the Hashtable type supports lock-free multiple readers and a single writer at the same time, while Dictionary does not.

What is the difference between bindParam and bindValue?

The simplest way to put this into perspective for memorization by behavior (in terms of PHP):

  • bindParam: reference
  • bindValue: variable

How to get local server host and port in Spring Boot?

One solution mentioned in a reply by @M. Deinum is one that I've used in a number of Akka apps:

object Localhost {

  /**
   * @return String for the local hostname
   */
  def hostname(): String = InetAddress.getLocalHost.getHostName

  /**
   * @return String for the host IP address
   */
  def ip(): String = InetAddress.getLocalHost.getHostAddress

}

I've used this method when building a callback URL for Oozie REST so that Oozie could callback to my REST service and it's worked like a charm

IF Statement multiple conditions, same statement

if (checkbox.checked && columnname != a && columnname != b && columnname != c)
    {
      "statement 1"
    }
else if (columnname != a && columnname != b && columnname != c 
        && columnname != A2)
    {
      "statement 1"
    }

is one way to simplify a little.

Keep values selected after form submission

<form method="get" action="">
 <select name="name" value="<?php echo $_GET['name'];?>">
   <option value="a">a</option>
   <option value="b">b</option>
 </select>
 <select name="location" value="<?php echo $_GET['location'];?>">
   <option value="x">x</option>
   <option value="y">y</option>
 </select>
   <input type="submit" value="Submit" class="submit" />
</form>

HTML 5 input type="number" element for floating point numbers on Chrome

Note: If you're using AngularJS, then in addition to changing the step value, you may have to set ng-model-options="{updateOn: 'blur change'}" on the html input.

The reason for this is in order to have the validators run less often, as they are preventing the user from entering a decimal point. This way, the user can type in a decimal point and the validators go into effect after the user blurs.

How to properly express JPQL "join fetch" with "where" clause as JPA 2 CriteriaQuery?

I will show visually the problem, using the great example from James answer and adding the alternative solution.

When you do the follow query, without the FETCH:

Select e from Employee e 
join e.phones p 
where p.areaCode = '613'

You will have the follow results from Employee as you expected:

EmployeeId EmployeeName PhoneId PhoneAreaCode
1 James 5 613
1 James 6 416

But when you add the FETCH word on JOIN, this is what happens:

EmployeeId EmployeeName PhoneId PhoneAreaCode
1 James 5 613

The generated SQL is the same for the two queries, but the Hibernate removes on memory the 416 register when you use WHERE on the FETCH join.

So, to bring all phones and apply the WHERE correctly, you need to have two JOINs: one for the WHERE and another for the FETCH. Like:

Select e from Employee e 
join e.phones p 
join fetch e.phones      //no alias, to not commit the mistake
where p.areaCode = '613'

Omit rows containing specific column of NA

Use 'subset'

DF <- data.frame(x = c(1, 2, 3), y = c(0, 10, NA), z=c(NA, 33, 22))
subset(DF, !is.na(y))

How do I Set Background image in Flutter?

body: Container(
    decoration: BoxDecoration(
      image: DecorationImage(
        image: AssetImage('images/background.png'),fit:BoxFit.cover
      )
    ),
);

How to change Label Value using javascript

Try

use an id for hidden field and use id of checkbox in javascript.

and change the ClientIDMode="static" too

<input type="hidden" ClientIDMode="static" id="label1" name="label206451" value="0" />

   <script type="text/javascript"> 
    var cb = document.getElementById('txt206451');
    var label = document.getElementById('label1');
    cb.addEventListener('click',function(evt){
    if(cb.checked){
        label.value='Thanks'
    }else{
        label.value='0'
    }
    },false);
    </script>

How to combine two lists in R

I was looking to do the same thing, but to preserve the list as a just an array of strings so I wrote a new code, which from what I've been reading may not be the most efficient but worked for what i needed to do:

combineListsAsOne <-function(list1, list2){
  n <- c()
  for(x in list1){
    n<-c(n, x)
  }
  for(y in list2){
    n<-c(n, y)
  }
  return(n)
}

It just creates a new list and adds items from two supplied lists to create one.

Python pandas: how to specify data types when reading an Excel file?

You just specify converters. I created an excel spreadsheet of the following structure:

names   ages
bob     05
tom     4
suzy    3

Where the "ages" column is formatted as strings. To load:

import pandas as pd

df = pd.read_excel('Book1.xlsx',sheetname='Sheet1',header=0,converters={'names':str,'ages':str})
>>> df
       names ages
   0   bob   05
   1   tom   4
   2   suzy  3

mySQL convert varchar to date

select date_format(str_to_date('31/12/2010', '%d/%m/%Y'), '%Y%m'); 

or

select date_format(str_to_date('12/31/2011', '%m/%d/%Y'), '%Y%m'); 

hard to tell from your example

Dropping connected users in Oracle database

I had the same problem, Oracle config in default affects letter register. In exact my Scheme_Name was written all Capital letters. You can see your Scheme_Name on "Other Users" tab, if you are using Oracle S

Releasing memory in Python

I'm guessing the question you really care about here is:

Is there a way to force Python to release all the memory that was used (if you know you won't be using that much memory again)?

No, there is not. But there is an easy workaround: child processes.

If you need 500MB of temporary storage for 5 minutes, but after that you need to run for another 2 hours and won't touch that much memory ever again, spawn a child process to do the memory-intensive work. When the child process goes away, the memory gets released.

This isn't completely trivial and free, but it's pretty easy and cheap, which is usually good enough for the trade to be worthwhile.

First, the easiest way to create a child process is with concurrent.futures (or, for 3.1 and earlier, the futures backport on PyPI):

with concurrent.futures.ProcessPoolExecutor(max_workers=1) as executor:
    result = executor.submit(func, *args, **kwargs).result()

If you need a little more control, use the multiprocessing module.

The costs are:

  • Process startup is kind of slow on some platforms, notably Windows. We're talking milliseconds here, not minutes, and if you're spinning up one child to do 300 seconds' worth of work, you won't even notice it. But it's not free.
  • If the large amount of temporary memory you use really is large, doing this can cause your main program to get swapped out. Of course you're saving time in the long run, because that if that memory hung around forever it would have to lead to swapping at some point. But this can turn gradual slowness into very noticeable all-at-once (and early) delays in some use cases.
  • Sending large amounts of data between processes can be slow. Again, if you're talking about sending over 2K of arguments and getting back 64K of results, you won't even notice it, but if you're sending and receiving large amounts of data, you'll want to use some other mechanism (a file, mmapped or otherwise; the shared-memory APIs in multiprocessing; etc.).
  • Sending large amounts of data between processes means the data have to be pickleable (or, if you stick them in a file or shared memory, struct-able or ideally ctypes-able).

Is there "\n" equivalent in VBscript?

I had to use vbLf only in an ASP script where the original data was POSTed from a PHP script on a cPanel box over to ASP on a win server

(VBScript)

EmailText = Replace(EmailText, vbLf, "<br>")

How to delete columns in pyspark dataframe

An easy way to do this is to user "select" and realize you can get a list of all columns for the dataframe, df, with df.columns

drop_list = ['a column', 'another column', ...]

df.select([column for column in df.columns if column not in drop_list])

Find a value anywhere in a database

If you need to run such search only once then you can probably go with any of the scripts already shown in other answers. But otherwise, I’d recommend using ApexSQL Search for this. It’s a free SSMS addin and it really saved me a lot of time.

Before running any of the scripts you should customize it based on the data type you want to search. If you know you are searching for datetime column then there is no need to search through nvarchar columns. This will speed up all of the queries above.

How to create jar file with package structure?

From the directory containing the com folder:

$ jar cvf asd.jar com
added manifest
adding: com/(in = 0) (out= 0)(stored 0%)
adding: com/cdy/(in = 0) (out= 0)(stored 0%)
adding: com/cdy/ws/(in = 0) (out= 0)(stored 0%)
adding: com/cdy/ws/a.class(in = 0) (out= 0)(stored 0%)
adding: com/cdy/ws/b.class(in = 0) (out= 0)(stored 0%)
adding: com/cdy/ws/c.class(in = 0) (out= 0)(stored 0%)

$ jar -tf asd.jar 
META-INF/
META-INF/MANIFEST.MF
com/
com/cdy/
com/cdy/ws/
com/cdy/ws/a.class
com/cdy/ws/b.class
com/cdy/ws/c.class

Disable single warning error

In certain situations you must have a named parameter but you don't use it directly.
For example, I ran into it on VS2010, when 'e' is used only inside a decltype statement, the compiler complains but you must have the named varible e.

All the above non-#pragma suggestions all boil down to just adding a single statement:

bool f(int e)
{ 
   // code not using e
   return true;
   e; // use without doing anything
}

How to mock location on device?

The Google tutorial for doing this can be found here, it provides code examples and explains the process.

http://developer.android.com/training/location/location-testing.html#SendMockLocations

Getting the error "Java.lang.IllegalStateException Activity has been destroyed" when using tabs with ViewPager

I encountered the same issue and lateron found out that, I have missed call to super.onCreate( savedInstanceState ); in onCreate() of FragmentActivity.

How to link to part of the same document in Markdown?

Using kramdown, it seems like this works well:

[I want this to link to foo](#foo)
....
....
{: id="foo"}
### Foo are you?

I see it's been mentioned that

[foo][#foo]
....
#Foo

works efficiently, but the former might be a good alternative for elements besides headers or else headers with multiple words.

SELECT * WHERE NOT EXISTS

You can also have a look at this related question. That user reported that using a join provided better performance than using a sub query.

scp from Linux to Windows

I know this is old but I was struggling with the same. I haven't found a way to change directories, but if you just want to work with the C drive, scp defaults to C. To scp from Ubuntu to Windows, I ended up having to use (notice the double back-slashes):

scp /local/file/path [email protected]:Users\\Anshul\\Desktop

Hope this helps someone.

How do I get the current date and time in PHP?

You can either use the $_SERVER['REQUEST_TIME'] variable (available since PHP 5.1.0) or the time() function to get the current Unix timestamp.

How to "pull" from a local branch into another one?

What you are looking for is merging.

git merge master

With pull you fetch changes from a remote repository and merge them into the current branch.

How to put two divs on the same line with CSS in simple_form in rails?

why not use flexbox ? so wrap them into another div like that

_x000D_
_x000D_
.flexContainer { _x000D_
   _x000D_
  margin: 2px 10px;_x000D_
  display: flex;_x000D_
} _x000D_
_x000D_
.left {_x000D_
  flex-basis : 30%;_x000D_
}_x000D_
_x000D_
.right {_x000D_
  flex-basis : 30%;_x000D_
}
_x000D_
<form id="new_production" class="simple_form new_production" novalidate="novalidate" method="post" action="/projects/1/productions" accept-charset="UTF-8">_x000D_
    <div style="margin:0;padding:0;display:inline">_x000D_
        <input type="hidden" value="?" name="utf8">_x000D_
        <input type="hidden" value="2UQCUU+tKiKKtEiDtLLNeDrfBDoHTUmz5Sl9+JRVjALat3hFM=" name="authenticity_token">_x000D_
    </div>_x000D_
    <div class="flexContainer">_x000D_
      <div class="left">Proj Name:</div>_x000D_
      <div class="right">must have a name</div>_x000D_
    </div>_x000D_
    <div class="input string required"> </div>_x000D_
 </form>
_x000D_
_x000D_
_x000D_

feel free to play with flex-basis percentage to get more customized space.

How to temporarily exit Vim and go back

Just put in fg and go back to your most recently suspended program.

Deleting Row in SQLite in Android

To delete rows from a table, you need to provide selection criteria that identify the rows to the delete() method. The mechanism works the same as the selection arguments to the query() method. It divides the selection specification into a selection clause(where clause) and selection arguments.

    SQLiteDatabase db  = this.getWritableDatabase();
     // Define 'where' part of query.
    String selection = Contract.COLUMN_COMPANY_ID + " =?  and "
                       + Contract.CLOUMN_TYPE +" =? ";
   // Specify arguments in placeholder order.
    String[] selectionArgs = { cid,mode };
    // Issue SQL statement.
    int deletedRows = db.delete(Contract.TABLE_NAME, 
                       selection, selectionArgs);
    return deletedRows;// no.of rows deleted.

The return value for the delete() method indicates the number of rows that were deleted from the database.

java.sql.SQLException: No suitable driver found for jdbc:microsoft:sqlserver

Following is a simple code to read from SQL database. Database names is "database1". Table name is "table1". It contain two columns "uname" and "pass". Dont forget to add "sqljdbc4.jar" to your project. Download sqljdbc4.jar

public class NewClass {

    public static void main(String[] args) {

        Connection conn = null;
        String dbName = "database1";
        String serverip="192.168.100.100";
        String serverport="1433";
        String url = "jdbc:sqlserver://"+serverip+"\\SQLEXPRESS:"+serverport+";databaseName="+dbName+"";
        Statement stmt = null;
        ResultSet result = null;
        String driver = "com.microsoft.sqlserver.jdbc.SQLServerDriver";
        String databaseUserName = "admin";
        String databasePassword = "root";
        try {
            Class.forName(driver).newInstance();
            conn = DriverManager.getConnection(url, databaseUserName, databasePassword);
            stmt = conn.createStatement();
            result = null;
            String pa,us;
            result = stmt.executeQuery("select * from table1 ");

            while (result.next()) {
                us=result.getString("uname");
                pa = result.getString("pass");              
                System.out.println(us+"  "+pa);
            }

            conn.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Password Protect a SQLite DB. Is it possible?

You can password protect a SQLite3 DB. Before doing any operations, set the password as follows.

SQLiteConnection conn = new SQLiteConnection("Data Source=MyDatabase.sqlite;Version=3;");
conn.SetPassword("password");
conn.Open();

then next time you can access it like

conn = new SQLiteConnection("Data Source=MyDatabase.sqlite;Version=3;Password=password;");
conn.Open();

This wont allow any GUI editor to view your data. Some editors can decrypt the DB if you provide the password. The algorithm used is RSA.

Later if you wish to change the password, use

conn.ChangePassword("new_password");

To reset or remove password, use

conn.ChangePassword(String.Empty);

release Selenium chromedriver.exe from memory

//Calling close and then quit will kill the driver running process.


driver.close();

driver.quit();

How to get child element by ID in JavaScript?

Here is a pure JavaScript solution (without jQuery)

var _Utils = function ()
{
    this.findChildById = function (element, childID, isSearchInnerDescendant) // isSearchInnerDescendant <= true for search in inner childern 
    {
        var retElement = null;
        var lstChildren = isSearchInnerDescendant ? Utils.getAllDescendant(element) : element.childNodes;

        for (var i = 0; i < lstChildren.length; i++)
        {
            if (lstChildren[i].id == childID)
            {
                retElement = lstChildren[i];
                break;
            }
        }

        return retElement;
    }

    this.getAllDescendant = function (element, lstChildrenNodes)
    {
        lstChildrenNodes = lstChildrenNodes ? lstChildrenNodes : [];

        var lstChildren = element.childNodes;

        for (var i = 0; i < lstChildren.length; i++) 
        {
            if (lstChildren[i].nodeType == 1) // 1 is 'ELEMENT_NODE'
            {
                lstChildrenNodes.push(lstChildren[i]);
                lstChildrenNodes = Utils.getAllDescendant(lstChildren[i], lstChildrenNodes);
            }
        }

        return lstChildrenNodes;
    }        
}
var Utils = new _Utils;

Example of use:

var myDiv = document.createElement("div");
myDiv.innerHTML = "<table id='tableToolbar'>" +
                        "<tr>" +
                            "<td>" +
                                "<div id='divIdToSearch'>" +
                                "</div>" +
                            "</td>" +
                        "</tr>" +
                    "</table>";

var divToSearch = Utils.findChildById(myDiv, "divIdToSearch", true);

Understanding the difference between Object.create() and new SomeFunction()

The difference is the so-called "pseudoclassical vs. prototypal inheritance". The suggestion is to use only one type in your code, not mixing the two.

In pseudoclassical inheritance (with "new" operator), imagine that you first define a pseudo-class, and then create objects from that class. For example, define a pseudo-class "Person", and then create "Alice" and "Bob" from "Person".

In prototypal inheritance (using Object.create), you directly create a specific person "Alice", and then create another person "Bob" using "Alice" as a prototype. There is no "class" here; all are objects.

Internally, JavaScript uses "prototypal inheritance"; the "pseudoclassical" way is just some sugar.

See this link for a comparison of the two ways.

How to make a back-to-top button using CSS and HTML only?

Hope this helps somebody!

<style> html { scroll-behavior: smooth;} </style>
<a id="top"></>
<!--content here-->
<a href="#top">Back to top..</a>

To prevent a memory leak, the JDBC Driver has been forcibly unregistered

I was having a similar problem, but additionally I was getting a Java Heap Space error anytime I modified/saved JSP pages with Tomcat server running, therefore the context were not fully recharged.

My versions were Apache Tomcat 6.0.29 and JDK 6u12.

Upgrading JDK to 6u21 as suggested in References section of URL http://wiki.apache.org/tomcat/MemoryLeakProtection solved the Java Heap Space problem (context now reloads OK) although JDBC Driver error still appears.

Adding click event handler to iframe

You can use closures to pass parameters:

iframe.document.addEventListener('click', function(event) {clic(this.id);}, false);

However, I recommend that you use a better approach to access your frame (I can only assume that you are using the DOM0 way of accessing frame windows by their name - something that is only kept around for backwards compatibility):

document.getElementById("myFrame").contentDocument.addEventListener(...);

Java Replace Character At Specific Position Of String?

To replace a character at a specified position :

public static String replaceCharAt(String s, int pos, char c) {
   return s.substring(0,pos) + c + s.substring(pos+1);
}

Eclipse Optimize Imports to Include Static Imports

I'm using Eclipse Europa, which also has the Favorite preference section:

Window > Preferences > Java > Editor > Content Assist > Favorites

In mine, I have the following entries (when adding, use "New Type" and omit the .*):

org.hamcrest.Matchers.*
org.hamcrest.CoreMatchers.*
org.junit.*
org.junit.Assert.*
org.junit.Assume.*
org.junit.matchers.JUnitMatchers.*

All but the third of those are static imports. By having those as favorites, if I type "assertT" and hit Ctrl+Space, Eclipse offers up assertThat as a suggestion, and if I pick it, it will add the proper static import to the file.

How do I rotate the Android emulator display?

You can use Numpad-9 and Numpad-7 to rotate on Windows and Ubuntu.

Create File If File Does Not Exist

private List<Url> AddURLToFile(Urls urls, Url url)
{
    string filePath = @"D:\test\file.json";
    urls.UrlList.Add(url);

    //if (!System.IO.File.Exists(filePath))
    //    using (System.IO.File.Delete(filePath));

    System.IO.File.WriteAllText(filePath, JsonConvert.SerializeObject(urls.UrlList));

    //using (StreamWriter sw = (System.IO.File.Exists(filePath)) ? System.IO.File.AppendText(filePath) : System.IO.File.CreateText(filePath))
    //{
    //    sw.WriteLine(JsonConvert.SerializeObject(urls.UrlList));
    //}
    return urls.UrlList;
}

private List<Url> ReadURLToFile()
{
    //  string filePath = Path.Combine(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location), @"App_Data\file.json");
    string filePath = @"D:\test\file.json";

    List<Url> result = new List<Url>(); ;
    if (!System.IO.File.Exists(filePath))
        using (System.IO.File.CreateText(filePath)) ;



    using (StreamReader file = new StreamReader(filePath))
    {
        result = JsonConvert.DeserializeObject<List<Url>>(file.ReadToEnd());
        file.Close();
    }
    if (result == null)
        result = new List<Url>();

    return result;

}

Dynamic SQL - EXEC(@SQL) versus EXEC SP_EXECUTESQL(@SQL)

sp_executesql is more likely to promote query plan reuse. When using sp_executesql, parameters are explicitly identified in the calling signature. This excellent article descibes this process.

The oft cited reference for many aspects of dynamic sql is Erland Sommarskog's must read: "The Curse and Blessings of Dynamic SQL".

How do I set the icon for my application in visual studio 2008?

The important thing is that the icon you want to be displayed as the application icon ( in the title bar and in the task bar ) must be the FIRST icon in the resource script file

The file is in the res folder and is named (applicationName).rc

/////////////////////////////////////////////////////////////////////////////
//
// Icon
//

// Icon with lowest ID value placed first to ensure application icon
// remains consistent on all systems.
(icon ID )          ICON                    "res\\filename.ico"

Get screen width and height in Android

I found weigan's answer best one in this page, here is how you can use that in Xamarin.Android:

public int GetScreenWidth()
{
    return Resources.System.DisplayMetrics.WidthPixels;
}

public int GetScreenHeight()
{
    return Resources.System.DisplayMetrics.HeightPixels;
}

String.equals versus ==

If you are going to compare any assigned value of the string i.e. primitive string, both "==" and .equals will work, but for the new string object you should use only .equals, and here "==" will not work.

Example:

String a = "name";

String b = "name";

if(a == b) and (a.equals(b)) will return true.

But

String a = new String("a");

In this case if(a == b) will return false

So it's better to use the .equals operator...

How can I modify a saved Microsoft Access 2007 or 2010 Import Specification?

Why so complicated?

Just check System Objects in Access-Options/Current Database/Navigation Options/Show System Objects

Open Table "MSysIMEXSpecs" and change according to your needs - its easy to read...

Dynamic array in C#

Use the array list which is actually implement array. It takes initially array of size 4 and when it gets full, a new array is created with its double size and the data of first array get copied into second array, now the new item is inserted into new array. Also the name of second array creates an alias of first so that it can be accessed by the same name as previous and the first array gets disposed

What does \0 stand for?

It means '\0' is a NULL character in C, don't know about Objective-C but its probably the same.

What is the difference between .NET Core and .NET Standard Class Library project types?

A .NET Core Class Library is built upon the .NET Standard. If you want to implement a library that is portable to the .NET Framework, .NET Core and Xamarin, choose a .NET Standard Library

.NET Core will ultimately implement .NET Standard 2 (as will Xamarin and .NET Framework)

.NET Core, Xamarin and .NET Framework can, therefore, be identified as flavours of .NET Standard

To future-proof your applications for code sharing and reuse, you would rather implement .NET Standard libraries.

Microsoft also recommends that you use .NET Standard instead of Portable Class Libraries.

To quote MSDN as an authoritative source, .NET Standard is intended to be One Library to Rule Them All. As pictures are worth a thousand words, the following will make things very clear:

1. Your current application scenario (fragmented)

Like most of us, you are probably in the situation below: (.NET Framework, Xamarin and now .NET Core flavoured applications)

Enter image description here

2. What the .NET Standard Library will enable for you (cross-framework compatibility)

Implementing a .NET Standard Library allows code sharing across all these different flavours:

One Library to Rule them All

For the impatient:

  1. .NET Standard solves the code sharing problem for .NET developers across all platforms by bringing all the APIs that you expect and love across the environments that you need: desktop applications, mobile apps & games, and cloud services:
  2. .NET Standard is a set of APIs that all .NET platforms have to implement. This unifies the .NET platforms and prevents future fragmentation.
  3. .NET Standard 2.0 will be implemented by .NET Framework, .NET Core, and Xamarin. For .NET Core, this will add many of the existing APIs that have been requested.
  4. .NET Standard 2.0 includes a compatibility shim for .NET Framework binaries, significantly increasing the set of libraries that you can reference from your .NET Standard libraries.
  5. .NET Standard will replace Portable Class Libraries (PCLs) as the tooling story for building multi-platform .NET libraries.

For a table to help understand what the highest version of .NET Standard that you can target, based on which .NET platforms you intend to run on, head over here.

Sources: MSDN: Introducing .NET Standard

Bootstrap 4 File Input

In case, if you need a no jquery solution

<label class="custom-file">
      <input type="file" id="myfile" class="custom-file-input" onchange="this.nextElementSibling.innerText = this.files[0].name">
      <span class="custom-file-control"></span>
</label>

Passing route control with optional parameter after root in express?

Express version:

"dependencies": {
    "body-parser": "^1.19.0",
    "express": "^4.17.1"
  }

Optional parameter are very much handy, you can declare and use them easily using express:

app.get('/api/v1/tours/:cId/:pId/:batchNo?', (req, res)=>{
    console.log("category Id: "+req.params.cId);
    console.log("product ID: "+req.params.pId);
    if (req.params.batchNo){
        console.log("Batch No: "+req.params.batchNo);
    }
});

In the above code batchNo is optional. Express will count it optional because after in URL construction, I gave a '?' symbol after batchNo '/:batchNo?'

Now I can call with only categoryId and productId or with all three-parameter.

http://127.0.0.1:3000/api/v1/tours/5/10
//or
http://127.0.0.1:3000/api/v1/tours/5/10/8987

enter image description here enter image description here

byte[] to hex string

Well I don't convert bytes to hex often so I have to say I don't know if there is a better way then this, but here is a way to do it.

StringBuilder sb = new StringBuilder();
foreach (byte b in myByteArray)
    sb.Append(b.ToString("X2"));

string hexString = sb.ToString();

Android Log.v(), Log.d(), Log.i(), Log.w(), Log.e() - When to use each one?

Let's go in reverse order:

  • Log.e: This is for when bad stuff happens. Use this tag in places like inside a catch statement. You know that an error has occurred and therefore you're logging an error.

  • Log.w: Use this when you suspect something shady is going on. You may not be completely in full on error mode, but maybe you recovered from some unexpected behavior. Basically, use this to log stuff you didn't expect to happen but isn't necessarily an error. Kind of like a "hey, this happened, and it's weird, we should look into it."

  • Log.i: Use this to post useful information to the log. For example: that you have successfully connected to a server. Basically use it to report successes.

  • Log.d: Use this for debugging purposes. If you want to print out a bunch of messages so you can log the exact flow of your program, use this. If you want to keep a log of variable values, use this.

  • Log.v: Use this when you want to go absolutely nuts with your logging. If for some reason you've decided to log every little thing in a particular part of your app, use the Log.v tag.

And as a bonus...

  • Log.wtf: Use this when stuff goes absolutely, horribly, holy-crap wrong. You know those catch blocks where you're catching errors that you never should get...yeah, if you wanna log them use Log.wtf

How to measure height, width and distance of object using camera?

If you know the viewport angle of the camera, you can use the height in pixels to determine the angle from the top to bottom of the object. Then, using the distance and arctangent calculate the height:

height = arctan(angle) * distance

To find the viewport angle, point the camera at something which is of known height, and make it exactly fill the screen. For example, point it at a ruler, and make it just far enough away that you can only barely see the ends of the ruler. Measure the distance from the camera, and then your total viewport angle is

viewportAngle = tan(ruler_length / distance)

Then, suppose your camera is 480px tall (cheap webcam), and the view angle is 20°. If you have an object onscreen which is 240px tall, then its angle is 10°. If you know it's 2 feet away, you would say 2 feet * arctan(10°) = ~4.1 inches tall. (I think... it's 2am so this may be a little off)

Python vs Bash - In which kind of tasks each one outruns the other performance-wise?

There are 2 scenario's where Bash performance is at least equal I believe:

  • Scripting of command line utilities
  • Scripts which take only a short time to execute; where starting the Python interpreter takes more time than the operation itself

That said, I usually don't really concern myself with performance of the scripting language itself. If performance is a real issue you don't script but program (possibly in Python).

Get Bitmap attached to ImageView

try this code:

Bitmap bitmap;
bitmap = ((BitmapDrawable)image.getDrawable()).getBitmap();

Get Maven artifact version at runtime

A simple solution which is Maven compatible and works for any (thus also third party) class:

    private static Optional<String> getVersionFromManifest(Class<?> clazz) {
        try {
            File file = new File(clazz.getProtectionDomain().getCodeSource().getLocation().toURI());
            if (file.isFile()) {
                JarFile jarFile = new JarFile(file);
                Manifest manifest = jarFile.getManifest();
                Attributes attributes = manifest.getMainAttributes();
                final String version = attributes.getValue("Bundle-Version");
                return Optional.of(version);
            }
        } catch (Exception e) {
            // ignore
        }
        return Optional.empty();
    }

An efficient way to Base64 encode a byte array?

byte[] base64EncodedStringBytes = Encoding.ASCII.GetBytes(Convert.ToBase64String(binaryData))

What is the difference between Numpy's array() and asarray() functions?

The definition of asarray is:

def asarray(a, dtype=None, order=None):
    return array(a, dtype, copy=False, order=order)

So it is like array, except it has fewer options, and copy=False. array has copy=True by default.

The main difference is that array (by default) will make a copy of the object, while asarray will not unless necessary.

REST API - Bulk Create or Update in single request

PUT ing

PUT /binders/{id}/docs Create or update, and relate a single document to a binder

e.g.:

PUT /binders/1/docs HTTP/1.1
{
  "docNumber" : 1
}

PATCH ing

PATCH /docs Create docs if they do not exist and relate them to binders

e.g.:

PATCH /docs HTTP/1.1
[
    { "op" : "add", "path" : "/binder/1/docs", "value" : { "doc_number" : 1 } },
    { "op" : "add", "path" : "/binder/8/docs", "value" : { "doc_number" : 8 } },
    { "op" : "add", "path" : "/binder/3/docs", "value" : { "doc_number" : 6 } }
] 

I'll include additional insights later, but in the meantime if you want to, have a look at RFC 5789, RFC 6902 and William Durand's Please. Don't Patch Like an Idiot blog entry.

How to use Macro argument as string literal?

Perhaps you try this solution:

#define QUANTIDISCHI 6
#define QUDI(x) #x
#define QUdi(x) QUDI(x)
. . . 
. . .
unsigned char TheNumber[] = "QUANTIDISCHI = " QUdi(QUANTIDISCHI) "\n";

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

I justed faced very similar problem... BUT RegExp_Count couldn't resolved it. How many times string '16,124,3,3,1,0,' contains ',3,'? As we see 2 times, but RegExp_Count returns just 1. Same thing is with ''bbaaaacc' and when looking in it 'aa' - should be 3 times and RegExp_Count returns just 2.

select REGEXP_COUNT('336,14,3,3,11,0,' , ',3,') from dual;
select REGEXP_COUNT('bbaaaacc' , 'aa') from dual;

I lost some time to research solution on web. Couldn't' find... so i wrote my own function that returns TRUE number of occurance. Hope it will be usefull.

CREATE OR REPLACE FUNCTION EXPRESSION_COUNT( pEXPRESSION VARCHAR2, pPHRASE VARCHAR2 ) RETURN NUMBER AS
  vRET NUMBER := 0;
  vPHRASE_LENGTH NUMBER := 0;
  vCOUNTER NUMBER := 0;
  vEXPRESSION VARCHAR2(4000);
  vTEMP VARCHAR2(4000);
BEGIN
  vEXPRESSION := pEXPRESSION;
  vPHRASE_LENGTH := LENGTH( pPHRASE );
  LOOP
    vCOUNTER := vCOUNTER + 1;
    vTEMP := SUBSTR( vEXPRESSION, 1, vPHRASE_LENGTH);
    IF (vTEMP = pPHRASE) THEN        
        vRET := vRET + 1;
    END IF;
    vEXPRESSION := SUBSTR( vEXPRESSION, 2, LENGTH( vEXPRESSION ) - 1);
  EXIT WHEN ( LENGTH( vEXPRESSION ) = 0 ) OR (vEXPRESSION IS NULL);
  END LOOP;
  RETURN vRET;
END;

How long is the SHA256 hash?

Encoding options for SHA256's 256 bits:

  1. Base64: 6 bits per char = CHAR(44) including padding character
  2. Hex: 4 bits per char = CHAR(64)
  3. Binary: 8 bits per byte = BINARY(32)

How to make use of ng-if , ng-else in angularJS

You can write as:

<div class="case" ng-if="mydata.id === '5' ">
    <p> this will execute </p>
</div>
<div class="case" ng-if="mydata.id !== '5' ">
    <p> this will execute </p>
</div> 

How to comment multiple lines with space or indent

Pressing Ctrl+K+C or Ctrl+E+C After selecting the lines you want to comment will not give space after slashes. you can use multiline select to provide space as suggested by Habib

Perhaps, you can use /* before the lines you want to comment and after */ in that case you might not need to provide spaces.

/*
  First Line to Comment
  Second Line to Comment
  Third Line to Comment      
*/

Detect the Internet connection is offline?

You can determine that the connection is lost by making failed XHR requests.

The standard approach is to retry the request a few times. If it doesn't go through, alert the user to check the connection, and fail gracefully.

Sidenote: To put the entire application in an "offline" state may lead to a lot of error-prone work of handling state.. wireless connections may come and go, etc. So your best bet may be to just fail gracefully, preserve the data, and alert the user.. allowing them to eventually fix the connection problem if there is one, and to continue using your app with a fair amount of forgiveness.

Sidenote: You could check a reliable site like google for connectivity, but this may not be entirely useful as just trying to make your own request, because while Google may be available, your own application may not be, and you're still going to have to handle your own connection problem. Trying to send a ping to google would be a good way to confirm that the internet connection itself is down, so if that information is useful to you, then it might be worth the trouble.

Sidenote: Sending a Ping could be achieved in the same way that you would make any kind of two-way ajax request, but sending a ping to google, in this case, would pose some challenges. First, we'd have the same cross-domain issues that are typically encountered in making Ajax communications. One option is to set up a server-side proxy, wherein we actually ping google (or whatever site), and return the results of the ping to the app. This is a catch-22 because if the internet connection is actually the problem, we won't be able to get to the server, and if the connection problem is only on our own domain, we won't be able to tell the difference. Other cross-domain techniques could be tried, for example, embedding an iframe in your page which points to google.com, and then polling the iframe for success/failure (examine the contents, etc). Embedding an image may not really tell us anything, because we need a useful response from the communication mechanism in order to draw a good conclusion about what's going on. So again, determining the state of the internet connection as a whole may be more trouble than it's worth. You'll have to weight these options out for your specific app.

How do I include a JavaScript script file in Angular and call a function from that script?

You can either

import * as abc from './abc';
abc.xyz();

or

import { xyz } from './abc';
xyz()

Implementing INotifyPropertyChanged - does a better way exist?

Based on the answer by Thomas which was adapted from an answer by Marc I've turned the reflecting property changed code into a base class:

public abstract class PropertyChangedBase : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    protected void OnPropertyChanged(string propertyName)
    {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (handler != null) 
            handler(this, new PropertyChangedEventArgs(propertyName));
    }

    protected void OnPropertyChanged<T>(Expression<Func<T>> selectorExpression)
    {
        if (selectorExpression == null)
            throw new ArgumentNullException("selectorExpression");
        var me = selectorExpression.Body as MemberExpression;

        // Nullable properties can be nested inside of a convert function
        if (me == null)
        {
            var ue = selectorExpression.Body as UnaryExpression;
            if (ue != null)
                me = ue.Operand as MemberExpression;
        }

        if (me == null)
            throw new ArgumentException("The body must be a member expression");

        OnPropertyChanged(me.Member.Name);
    }

    protected void SetField<T>(ref T field, T value, Expression<Func<T>> selectorExpression, params Expression<Func<object>>[] additonal)
    {
        if (EqualityComparer<T>.Default.Equals(field, value)) return;
        field = value;
        OnPropertyChanged(selectorExpression);
        foreach (var item in additonal)
            OnPropertyChanged(item);
    }
}

Usage is the same as Thomas' answer except that you can pass additional properties to notify for. This was necessary to handle calculated columns which need to be refreshed in a grid.

private int _quantity;
private int _price;

public int Quantity 
{ 
    get { return _quantity; } 
    set { SetField(ref _quantity, value, () => Quantity, () => Total); } 
}
public int Price 
{ 
    get { return _price; } 
    set { SetField(ref _price, value, () => Price, () => Total); } 
}
public int Total { get { return _price * _quantity; } }

I have this driving a collection of items stored in a BindingList exposed via a DataGridView. It has eliminated the need for me to do manual Refresh() calls to the grid.

npm - how to show the latest version of a package

If you're looking for the current and the latest versions of all your installed packages, you can also use:

npm outdated

mySQL Error 1040: Too Many Connection

In your program you would have opened the connections and left open without closing it.

I faced a same problem and finally identified.

I added this code, after try catch.

finally{
    try {
        rs.close();
        p.close();
        conn.close();
    } catch (SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

How to parse a string in JavaScript?

Use split on string:

var array = coolVar.split(/-/);

Get Category name from Post ID

echo '<p>'. get_the_category( $id )[0]->name .'</p>';

is what you maybe looking for.

ImportError: No module named 'Tkinter'

I think you should try this:

from tkinter import *

or

from Tkinter import *

It really depends on what type of computer you use, or what version of python you have.

Chrome hangs after certain amount of data transfered - waiting for available socket

Chrome is a Chromium-based browser and Chromium-based browsers only allow maximum 6 open socket connections at a time, when the 7th connection starts up it will just sit idle and wait for one of the 6 which are running to stop and then it will start running. Hence the error code ‘waiting for available sockets’, the 7th one will wait for one of those 6 sockets to become available and then it will start running.

You can either

Difference between Select Unique and Select Distinct

select unique is not valid syntax for what you are trying to do

you want to use either select distinct or select distinctrow

And actually, you don't even need distinct/distinctrow in what you are trying to do. You can eliminate duplicates by choosing the appropriate union statement parameters.

the below query by itself will only provide distinct values

select col from table1 
union 
select col from table2

if you did want duplicates you would have to do

select col from table1 
union all
select col from table2