Programs & Examples On #Wxwidgets

wxWidgets is a cross-platform GUI framework. It is written in C++ and has bindings for Python, Perl, Ruby, PHP, Erlang and even .Net. It also supports several mobile platforms including Windows Mobile, iPhone SDK and embedded GTK+.

Python ImportError: No module named wx

Just open your terminal and run this command thats for windows users pip install -U wxPython

for Ubuntu user you can use this

pip install -U \
-f https://extras.wxpython.org/wxPython4/extras/linux/gtk3/ubuntu-16.04 \
wxPython

Is there any 'out-of-the-box' 2D/3D plotting library for C++?

OpenGL. It WILL be hard and possibly rewriting the wheel, though. Keep in mind that OpenGL is a general 3D library, and not a specific plot library, but you can implement plotting based on it.

How can I disable HREF if onclick is executed?

This might help. No JQuery needed

<a href="../some-relative-link/file" 
onclick="this.href = 'https://docs.google.com/viewer?url='+this.href; this.onclick = '';" 
target="_blank">

This code does the following: Pass the relative link to Google Docs Viewer

  1. Get the full link version of the anchor by this.href
  2. open the link the the new window.

So in your case this might work:

<a href="../some-relative-link/file" 
onclick="this.href = 'javascript:'+console.log('something has stopped the link'); " 
target="_blank">

How to switch from the default ConstraintLayout to RelativeLayout in Android Studio

  1. Right click on ConstraintLayout.
  2. Select convertview.
  3. select RelativeLayout

For more clarity refer below image

enter image description here

Embed ruby within URL : Middleman Blog

<%= link_to "http://www.facebook.com/sharer.php?u=" + article_url(article, :text => article.title), :class => "btn btn-primary" do %>   <i class="fa fa-facebook">     Facebook Share    </i> <%end%> 

I am assuming that current_article_url is http://0.0.0.0:4567/link_to_title

Template not provided using create-react-app

npx create-react-app@latest your-project-name

work for me after trying all the answers hope that can help someone in the future.

What is the difference between \r and \n?

In C and C++, \n is a concept, \r is a character, and \r\n is (almost always) a portability bug.

Think of an old teletype. The print head is positioned on some line and in some column. When you send a printable character to the teletype, it prints the character at the current position and moves the head to the next column. (This is conceptually the same as a typewriter, except that typewriters typically moved the paper with respect to the print head.)

When you wanted to finish the current line and start on the next line, you had to do two separate steps:

  1. move the print head back to the beginning of the line, then
  2. move it down to the next line.

ASCII encodes these actions as two distinct control characters:

  • \x0D (CR) moves the print head back to the beginning of the line. (Unicode encodes this as U+000D CARRIAGE RETURN.)
  • \x0A (LF) moves the print head down to the next line. (Unicode encodes this as U+000A LINE FEED.)

In the days of teletypes and early technology printers, people actually took advantage of the fact that these were two separate operations. By sending a CR without following it by a LF, you could print over the line you already printed. This allowed effects like accents, bold type, and underlining. Some systems overprinted several times to prevent passwords from being visible in hardcopy. On early serial CRT terminals, CR was one of the ways to control the cursor position in order to update text already on the screen.

But most of the time, you actually just wanted to go to the next line. Rather than requiring the pair of control characters, some systems allowed just one or the other. For example:

  • Unix variants (including modern versions of Mac) use just a LF character to indicate a newline.
  • Old (pre-OSX) Macintosh files used just a CR character to indicate a newline.
  • VMS, CP/M, DOS, Windows, and many network protocols still expect both: CR LF.
  • Old IBM systems that used EBCDIC standardized on NL--a character that doesn't even exist in the ASCII character set. In Unicode, NL is U+0085 NEXT LINE, but the actual EBCDIC value is 0x15.

Why did different systems choose different methods? Simply because there was no universal standard. Where your keyboard probably says "Enter", older keyboards used to say "Return", which was short for Carriage Return. In fact, on a serial terminal, pressing Return actually sends the CR character. If you were writing a text editor, it would be tempting to just use that character as it came in from the terminal. Perhaps that's why the older Macs used just CR.

Now that we have standards, there are more ways to represent line breaks. Although extremely rare in the wild, Unicode has new characters like:

  • U+2028 LINE SEPARATOR
  • U+2029 PARAGRAPH SEPARATOR

Even before Unicode came along, programmers wanted simple ways to represent some of the most useful control codes without worrying about the underlying character set. C has several escape sequences for representing control codes:

  • \a (for alert) which rings the teletype bell or makes the terminal beep
  • \f (for form feed) which moves to the beginning of the next page
  • \t (for tab) which moves the print head to the next horizontal tab position

(This list is intentionally incomplete.)

This mapping happens at compile-time--the compiler sees \a and puts whatever magic value is used to ring the bell.

Notice that most of these mnemonics have direct correlations to ASCII control codes. For example, \a would map to 0x07 BEL. A compiler could be written for a system that used something other than ASCII for the host character set (e.g., EBCDIC). Most of the control codes that had specific mnemonics could be mapped to control codes in other character sets.

Huzzah! Portability!

Well, almost. In C, I could write printf("\aHello, World!"); which rings the bell (or beeps) and outputs a message. But if I wanted to then print something on the next line, I'd still need to know what the host platform requires to move to the next line of output. CR LF? CR? LF? NL? Something else? So much for portability.

C has two modes for I/O: binary and text. In binary mode, whatever data is sent gets transmitted as-is. But in text mode, there's a run-time translation that converts a special character to whatever the host platform needs for a new line (and vice versa).

Great, so what's the special character?

Well, that's implementation dependent, too, but there's an implementation-independent way to specify it: \n. It's typically called the "newline character".

This is a subtle but important point: \n is mapped at compile time to an implementation-defined character value which (in text mode) is then mapped again at run time to the actual character (or sequence of characters) required by the underlying platform to move to the next line.

\n is different than all the other backslash literals because there are two mappings involved. This two-step mapping makes \n significantly different than even \r, which is simply a compile-time mapping to CR (or the most similar control code in whatever the underlying character set is).

This trips up many C and C++ programmers. If you were to poll 100 of them, at least 99 will tell you that \n means line feed. This is not entirely true. Most (perhaps all) C and C++ implementations use LF as the magic intermediate value for \n, but that's an implementation detail. It's feasible for a compiler to use a different value. In fact, if the host character set is not a superset of ASCII (e.g., if it's EBCDIC), then \n will almost certainly not be LF.

So, in C and C++:

  • \r is literally a carriage return.
  • \n is a magic value that gets translated (in text mode) at run-time to/from the host platform's newline semantics.
  • \r\n is almost always a portability bug. In text mode, this gets translated to CR followed by the platform's newline sequence--probably not what's intended. In binary mode, this gets translated to CR followed by some magic value that might not be LF--possibly not what's intended.
  • \x0A is the most portable way to indicate an ASCII LF, but you only want to do that in binary mode. Most text-mode implementations will treat that like \n.

Background color in input and text fields

The best solution is the attribute selector in CSS (input[type="text"]) as the others suggested.

But if you have to support Internet Explorer 6, you cannot use it (QuirksMode). Well, only if you have to and also are willing to support it.

In this case your only option seems to be to define classes on input elements.

<input type="text" class="input-box" ... />
<input type="submit" class="button" ... />
...

and target them with a class selector:

input.input-box, textarea { background: cyan; }

Remove the newline character in a list read from a file

str.strip() returns a string with leading+trailing whitespace removed, .lstrip and .rstrip for only leading and trailing respectively.

grades.append(lists[i].rstrip('\n').split(','))

xcopy file, rename, suppress "Does xxx specify a file name..." message

So, there is a simple fix for this. It is admittedly awkward, but it works. xcopy will not prompt to find out if the destination is a directory or file IF the new file(filename) already exists. If you precede your xcopy command with a simple echo to the new filename, it will overwrite the empty file. Example

echo.>newfile.txt
xcopy oldfile.txt newfile.txt /Y

How do I send a POST request with PHP?

The better way of sending GET or POST requests with PHP is as below:

<?php
    $r = new HttpRequest('http://example.com/form.php', HttpRequest::METH_POST);
    $r->setOptions(array('cookies' => array('lang' => 'de')));
    $r->addPostFields(array('user' => 'mike', 'pass' => 's3c|r3t'));

    try {
        echo $r->send()->getBody();
    } catch (HttpException $ex) {
        echo $ex;
    }
?>

The code is taken from official documentation here http://docs.php.net/manual/da/httprequest.send.php

How to change UINavigationBar background color from the AppDelegate

You can easily do this with Xcode 6.3.1. Select your NavigationBar in the Document outline. Select the Attributes Inspector. Uncheck Translucent. Set Bar Tint to your desired color. Done!

Abstract methods in Python

You can't, with language primitives. As has been called out, the abc package provides this functionality in Python 2.6 and later, but there are no options for Python 2.5 and earlier. The abc package is not a new feature of Python; instead, it adds functionality by adding explicit "does this class say it does this?" checks, with manually-implemented consistency checks to cause an error during initialization if such declarations are made falsely.

Python is a militantly dynamically-typed language. It does not specify language primitives to allow you to prevent a program from compiling because an object does not match type requirements; this can only be discovered at run time. If you require that a subclass implement a method, document that, and then just call the method in the blind hope that it will be there.

If it's there, fantastic, it simply works; this is called duck typing, and your object has quacked enough like a duck to satisfy the interface. This works just fine even if self is the object you're calling such a method on, for the purposes of mandatory overrides due to base methods that need specific implementations of features (generic functions), because self is a convention, not anything actually special.

The exception is in __init__, because when your initializer is being called, the derived type's initializer hasn't, so it hasn't had the opportunity to staple its own methods onto the object yet.

If the method was't implemented, you'll get an AttributeError (if it's not there at all) or a TypeError (if something by that name is there but it's not a function or it didn't have that signature). It's up to you how you handle that- either call it programmer error and let it crash the program (and it "should" be obvious to a python developer what causes that kind of error there- an unmet duck interface), or catch and handle those exceptions when you discover that your object didn't support what you wish it did. Catching AttributeError and TypeError is important in a lot of situations, actually.

What is the difference between Html.Hidden and Html.HiddenFor

Every method in HtmlHelper class has a twin with For suffix. Html.Hidden takes a string as an argument that you must provide but Html.HiddenFor takes an Expression that if you view is a strongly typed view you can benefit from this and feed that method a lambda expression like this

o=>o.SomeProperty 

instead of "SomeProperty" in the case of using Html.Hidden method.

Remove redundant paths from $PATH variable

Here is a one line code that cleans up the PATH

  • It does not disturb the order of the PATH, just removes duplicates
  • Treats : and empth PATH gracefully
  • No special characters used, so does not require escape
  • Uses /bin/awk so it works even when PATH is broken

    export PATH="$(echo "$PATH" |/bin/awk 'BEGIN{RS=":";}
    {sub(sprintf("%c$",10),"");if(A[$0]){}else{A[$0]=1;
    printf(((NR==1)?"":":")$0)}}')";
    

React Native Error: ENOSPC: System limit for number of file watchers reached

The meaning of this error is that the number of files monitored by the system has reached the limit!!

Result: The command executed failed! Or throw a warning (such as executing a react-native start VSCode)

Solution:

Modify the number of system monitoring files

Ubuntu

sudo gedit /etc/sysctl.conf

Add a line at the bottom

fs.inotify.max_user_watches=524288

Then save and exit!

sudo sysctl -p

to check it

Then it is solved!

Struct inheritance in C++

Yes, c++ struct is very similar to c++ class, except the fact that everything is publicly inherited, ( single / multilevel / hierarchical inheritance, but not hybrid and multiple inheritance ) here is a code for demonstration

_x000D_
_x000D_
#include<bits/stdc++.h>
using namespace std;

struct parent
{
    int data;
    parent() : data(3){};           // default constructor
    parent(int x) : data(x){};      // parameterized constructor
};
struct child : parent
{
    int a , b;
    child(): a(1) , b(2){};             // default constructor
    child(int x, int y) : a(x) , b(y){};// parameterized constructor
    child(int x, int y,int z)           // parameterized constructor
    {
        a = x;
        b = y;
        data = z;
    }
    child(const child &C)               // copy constructor
    {
        a = C.a;
        b = C.b;
        data = C.data;
    }
};
int main()
{
   child c1 ,
         c2(10 , 20),
         c3(10 , 20, 30),
         c4(c3);

    auto print = [](const child &c) { cout<<c.a<<"\t"<<c.b<<"\t"<<c.data<<endl; };

    print(c1);
    print(c2);
    print(c3);
    print(c4);
}
OUTPUT 
1       2       3
10      20      3
10      20      30
10      20      30
_x000D_
_x000D_
_x000D_

random number generator between 0 - 1000 in c#

Use this:

static int RandomNumber(int min, int max)
{
    Random random = new Random(); return random.Next(min, max);

}

This is example for you to modify and use in your application.

How do I upgrade PHP in Mac OS X?

Before I go on, I have the latest version (v5.0.15) of OS X Server (yes, horrible, I know...however, the web server seems to work A-OK). I searched high and low for days trying to update (or at least get Apache to point to) a new version of PHP. My mcrypt did not work, along with other extensions and I installed and reinstalled PHP countless times from http://php-osx.liip.ch/ and other tutorials until I finally noticed a tid-bit of information written in a comment in one of the many different .conf files OS X Server keeps which was that OS X Server loads it's own custom .conf file before it loads the Apache httpd.conf (located at /etc/apache2/httpd.conf). The server file is located:

/Library/Server/Web/Config/apache2/httpd_server_app.conf

When you open this file, you have to comment out this line like so:

#LoadModule php5_module libexec/apache2/libphp5.so

Then add in the correct path (which should already be installed if you have installed via the http://php-osx.liip.ch/ link):

LoadModule php5_module /usr/local/php5/libphp5.so

After this modification, my PHP finally loaded the correct PHP installation. That being said, if things go wonky, it may be because OS X is made to work off the native installation of PHP at the time of OS X installation. To revert, just undo the change above.

Anyway, hopefully this is helpful for anyone else spending countless hours on this.

How to set app icon for Electron / Atom Shell App

If you want to update the app icon in the taskbar, then Update following in main.js (if using typescript then main.ts)

win.setIcon(path.join(__dirname, '/src/assets/logo-small.png'));

__dirname points to the root directory (same directory as package.json) of your application.

Chmod 777 to a folder and all contents

for mac, should be a ‘superuser do’;

so first :

sudo -s 
password:

and then

chmod -R 777 directory_path

How to create localhost database using mysql?

See here for starting the service and here for how to make it permanent. In short to test it, open a "DOS" terminal with administrator privileges and write:

shell> "C:\Program Files\MySQL\[YOUR MYSQL VERSION PATH]\bin\mysqld"

Open File Dialog, One Filter for Multiple Excel Extensions?

Use a semicolon

OpenFileDialog of = new OpenFileDialog();
of.Filter = "Excel Files|*.xls;*.xlsx;*.xlsm";

how to open popup window using jsp or jquery?

<a href="javaScript:{openPopUp();}"></a>
<form action="actionName">
<div id="divId" style="display:none;">
UsreName:<input type="text" name="userName"/>
</div>
</form>

function openPopUp()
{
  $('#divId').css('display','block');
$('#divId').dialog();
}

How to get the selected date value while using Bootstrap Datepicker?

You can try this

$('#startdate').val()

or

$('#startdate').data('date')

Safest way to convert float to integer in python?

df['Column_Name']=df['Column_Name'].astype(int)

ORA-28040: No matching authentication protocol exception

This except for adding the following to sqlnet.ora

SQLNET.ALLOWED_LOGON_VERSION_CLIENT = 8
SQLNET.ALLOWED_LOGON_VERSION_SERVER = 8

If you get "ORA-01017: invalid username/password; logon denied" error, then you need to re-create your password.

Delete a row in Excel VBA

Something like this will do it:

Rows("12:12").Select
Selection.Delete

So in your code it would look like something like this:

Rows(CStr(rand) & ":" & CStr(rand)).Select
Selection.Delete

Field 'browser' doesn't contain a valid alias configuration

In my case, to the very end of the webpack.config.js, where I should exports the config, there was a typo: export(should be exports), which led to failure with loading webpack.config.js at all.

const path = require('path');

const config = {
    mode: 'development',
    entry: "./lib/components/Index.js",
    output: {
        path: path.resolve(__dirname, 'public'),
        filename: 'bundle.js'
    },
    module: {
        rules: [
            {
                test: /\.js$/,
                loader: 'babel-loader',
                exclude: path.resolve(__dirname, "node_modules")
            }
        ]
    }
}

// pay attention to "export!s!" here
module.exports = config;

Disable firefox same origin policy

In about:config add content.cors.disable (empty string).

Chrome not rendering SVG referenced via <img> tag

looks like a Chrome bug, i did something else as i almost got crazy because of this... using Chrom debugger if you change the css of the svg object it shows on the screen.

so what i did was: 1. check for screen size 2. listen to the "load" event of my SVG object 3. when the element is loaded i change its css using jQuery 4. it did the trick for me

_x000D_
_x000D_
if (jQuery(window).width() < 769) {_x000D_
_x000D_
  jQuery('object#mysvg-logo')[0].addEventListener('load', function() {_x000D_
       jQuery("object#mysvg-logo").css('width','181px');_x000D_
  }, true);_x000D_
_x000D_
}
_x000D_
width: 180px;
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>_x000D_
<object id="mysvg-logo" type="image/svg+xml" data="my svg logo url here">Your browser does not support SVG</object>
_x000D_
_x000D_
_x000D_

Can I get Unix's pthread.h to compile in Windows?

There are, as i recall, two distributions of the gnu toolchain for windows: mingw and cygwin.

I'd expect cygwin work - a lot of effort has been made to make that a "stadard" posix environment.

The mingw toolchain uses msvcrt.dll for its runtime and thus will probably expose msvcrt's "thread" api: _beginthread which is defined in <process.h>

Tomcat is web server or application server?

Apache Tomcat is an open source software implementation of the Java Servlet and JavaServer Pages technologies.

Since Tomcat does not implement the full Java EE specification for an application server, it can be considered as a web server.

Source: http://tomcat.apache.org

Set scroll position

... Or just replace body by documentElement:

document.documentElement.scrollTop = 0;

Make a bucket public in Amazon S3

Amazon provides a policy generator tool:

https://awspolicygen.s3.amazonaws.com/policygen.html

After that, you can enter the policy requirements for the bucket on the AWS console:

https://console.aws.amazon.com/s3/home

How to allow only numbers in textbox in mvc4 razor

@Html.TextBoxFor(x => x.MobileNo, new { @class = "digit" , @maxlength = "10"})

@section Scripts 
{
    @Scripts.Render("~/bundles/jqueryui")
    @Styles.Render("~/Content/cssjqryUi")

    <script type="text/javascript">
         $(".digit").keypress(function (e) {
            if (e.which != 8 && e.which != 0 && (e.which < 48 || e.which > 57)) 
            {
                $("#errormsg").html("Digits Only").show().fadeOut("slow");
                return false;
            }
         });
    </script>
}

remove kernel on jupyter notebook

Just for completeness, you can get a list of kernels with jupyter kernelspec list, but I ran into a case where one of the kernels did not show up in this list. You can find all kernel names by opening a Jupyter notebook and selecting Kernel -> Change kernel. If you do not see everything in this list when you run jupyter kernelspec list, try looking in common Jupyter folders:

ls ~/.local/share/jupyter/kernels  # usually where local kernels go
ls /usr/local/share/jupyter/kernels  # usually where system-wide kernels go
ls /usr/share/jupyter/kernels  # also where system-wide kernels can go

Also, you can delete a kernel with jupyter kernelspec remove or jupyter kernelspec uninstall. The latter is an alias for remove. From the in-line help text for the command:

uninstall
    Alias for remove
remove
    Remove one or more Jupyter kernelspecs by name.

How to set environment variables in Python?

It should be noted that if you try to set the environment variable to a bash evaluation it won't store what you expect. Example:

from os import environ

environ["JAVA_HOME"] = "$(/usr/libexec/java_home)"

This won't evaluate it like it does in a shell, so instead of getting /Library/Java/JavaVirtualMachines/jdk1.8.0_144.jdk/Contents/Home as a path you will get the literal expression $(/usr/libexec/java_home).

Make sure to evaluate it before setting the environment variable, like so:

from os import environ
from subprocess import Popen, PIPE

bash_variable = "$(/usr/libexec/java_home)"
capture = Popen(f"echo {bash_variable}", stdout=PIPE, shell=True)
std_out, std_err = capture.communicate()
return_code = capture.returncode

if return_code == 0:
    evaluated_env = std_out.decode().strip()
    environ["JAVA_HOME"] = evaluated_env
else:
    print(f"Error: Unable to find environment variable {bash_variable}")

How can I troubleshoot Python "Could not find platform independent libraries <prefix>"

If you made a virtual env, then deleted that python installation, you'll get the same error. Just rm -r your venv folder, then recreate it with a valid python location and do pip install -r requirements.txt and you'll be all set (assuming you got your requirements.txt right).

How to update gradle in android studio?

Open File > Project Structure > Project Tab

enter image description here

Android Studio has built in project structure menu to check and update gradle and plugin used in the current project.

Below Website gives a detailed explanation on how to update gradle and gradle plugin of Android Studio.

Update gradle plugin Android Studio

Rename multiple files in a folder, add a prefix (Windows)

The problem with the two Powershell answers here is that the prefix can end up being duplicated since the script will potentially run over the file both before and after it has been renamed, depending on the directory being resorted as the renaming process runs. To get around this, simply use the -Exclude option:

Get-ChildItem -Exclude "house chores-*" | rename-item -NewName { "house chores-" + $_.Name }

This will prevent the process from renaming any one file more than once.

Removing fields from struct or hiding them in JSON Response

I didn't have the same problem but similar. Below code solves your problem too, of course if you don't mind performance issue. Before implement that kind of solution to your system I recommend you to redesign your structure if you can. Sending variable structure response is over-engineering. I believe a response structure represents a contract between a request and resource and it should't be depend requests.(you can make un-wanted fields null, I do). In some cases we have to implement this design, if you believe you are in that cases here is the play link and code I use.

type User2 struct {
    ID       int    `groups:"id" json:"id,omitempty"`
    Username string `groups:"username" json:"username,omitempty"`
    Nickname string `groups:"nickname" json:"nickname,omitempty"`
}

type User struct {
    ID       int    `groups:"private,public" json:"id,omitempty"`
    Username string `groups:"private" json:"username,omitempty"`
    Nickname string `groups:"public" json:"nickname,omitempty"`
}

var (
    tagName = "groups"
)

//OmitFields sets fields nil by checking their tag group value and access control tags(acTags)
func OmitFields(obj interface{}, acTags []string) {
    //nilV := reflect.Value{}
    sv := reflect.ValueOf(obj).Elem()
    st := sv.Type()
    if sv.Kind() == reflect.Struct {
        for i := 0; i < st.NumField(); i++ {
            fieldVal := sv.Field(i)
            if fieldVal.CanSet() {
                tagStr := st.Field(i).Tag.Get(tagName)
                if len(tagStr) == 0 {
                    continue
                }
                tagList := strings.Split(strings.Replace(tagStr, " ", "", -1), ",")
                //fmt.Println(tagList)
                // ContainsCommonItem checks whether there is at least one common item in arrays
                if !ContainsCommonItem(tagList, acTags) {
                    fieldVal.Set(reflect.Zero(fieldVal.Type()))
                }
            }
        }
    }
}

//ContainsCommonItem checks if arrays have at least one equal item
func ContainsCommonItem(arr1 []string, arr2 []string) bool {
    for i := 0; i < len(arr1); i++ {
        for j := 0; j < len(arr2); j++ {
            if arr1[i] == arr2[j] {
                return true
            }
        }
    }
    return false
}
func main() {
    u := User{ID: 1, Username: "very secret", Nickname: "hinzir"}
    //assume authenticated user doesn't has permission to access private fields
    OmitFields(&u, []string{"public"}) 
    bytes, _ := json.Marshal(&u)
    fmt.Println(string(bytes))


    u2 := User2{ID: 1, Username: "very secret", Nickname: "hinzir"}
    //you want to filter fields by field names
    OmitFields(&u2, []string{"id", "nickname"}) 
    bytes, _ = json.Marshal(&u2)
    fmt.Println(string(bytes))

}

Subtract days from a DateTime

The object (i.e. destination variable) for the AddDays method can't be the same as the source.

Instead of:

DateTime today = DateTime.Today;
today.AddDays(-7);

Try this instead:

DateTime today = DateTime.Today;
DateTime sevenDaysEarlier = today.AddDays(-7);

Django set field value after a form is initialized

in widget use 'value' attr. Example:

username = forms.CharField(
    required=False,
    widget=forms.TextInput(attrs={'readonly': True, 'value': 'CONSTANT_VALUE'}),
)

Adding line break in C# Code behind page

Strings are immutable, so using

public string GenerateString()
{
    return
        "abc" +
        "def";
}

will slow you performance - each of those values is a string literal which must be concatenated at runtime - bad news if you reuse the method/property/whatever alot...

Store your string literals in resources is a good idea...

public string GenerateString()
{
    return Resources.MyString;
}

That way it is localisable and the code is tidy (although performance is pretty terrible).

Can dplyr join on multiple columns or composite key?

Updating to use tibble()

You can pass a named vector of length greater than 1 to the by argument of left_join():

library(dplyr)

d1 <- tibble(
  x = letters[1:3],
  y = LETTERS[1:3],
  a = rnorm(3)
  )

d2 <- tibble(
  x2 = letters[3:1],
  y2 = LETTERS[3:1],
  b = rnorm(3)
  )

left_join(d1, d2, by = c("x" = "x2", "y" = "y2"))

MySQL: Can't create/write to file '/tmp/#sql_3c6_0.MYI' (Errcode: 2) - What does it even mean?

I meet this error too when I run a wordpress on my Fedora system.

I googled it, and find a way to fix this.

Maybe this will help you too.

  1. check mysql config : my.cnf

     cat /etc/my.cnf | grep tmpdir
    

    I can't see anything in my my.cnf

  2. add tmpdir=/tmp to my.cnf under [mysqld]

  3. restart web/app and mysql server

    /etc/init.d/mysqld restart

In Perl, how to remove ^M from a file?

I prefer a more general solution that will work with either DOS or Unix input. Assuming the input is from STDIN:

while (defined(my $ln = <>))
  {
    chomp($ln);
    chop($ln) if ($ln =~ m/\r$/);

    # filter and write
  }

How to set a string's color

If you're printing to stdout, it depends on the terminal you're printing to. You can use ansi escape codes on xterms and other similar terminal emulators. Here's a bash code snippet that will print all 255 colors supported by xterm, putty and Konsole:

 for ((i=0;i<256;i++)); do echo -en "\e[38;5;"$i"m"$i" "; done

You can use these escape codes in any programming language. It's better to rely on a library that will decide which codes to use depending on architecture and the content of the TERM environment variable.

Maven 3 and JUnit 4 compilation problem: package org.junit does not exist

Add this dependency to your pom.xml file:

http://mvnrepository.com/artifact/junit/junit-dep/4.8.2

<!-- https://mvnrepository.com/artifact/junit/junit-dep -->
<dependency>
    <groupId>junit</groupId>
    <artifactId>junit-dep</artifactId>
    <version>4.8.2</version>
</dependency>

MySQL date format DD/MM/YYYY select query?

ORDER BY a date type does not depend on the date format, the date format is only for showing, in the database, they are same data.

Can I add background color only for padding?

There is no exact functionality to do this.

Without wrapping another element inside, you could replace the border by a box-shadow and the padding by the border. But remember the box-shadow does not add to the dimensions of the element.

jsfiddle is being really slow, otherwise I'd add an example.

google chrome extension :: console.log() from background page?

To answer your question directly, when you call console.log("something") from the background, this message is logged, to the background page's console. To view it, you may go to chrome://extensions/ and click on that inspect view under your extension.

When you click the popup, it's loaded into the current page, thus the console.log should show log message in the current page.

How to check if a json key exists?

JSONObject class has a method named "has":

http://developer.android.com/reference/org/json/JSONObject.html#has(java.lang.String)

Returns true if this object has a mapping for name. The mapping may be NULL.

How to iterate through SparseArray?

Simple as Pie. Just make sure you fetch array size before actually performing the loop.

for(int i = 0, arraySize= mySparseArray.size(); i < arraySize; i++) {
   Object obj = mySparseArray.get(/* int key = */ mySparseArray.keyAt(i));
}

Hope this helps.

How can I "disable" zoom on a mobile web page?

<script type="text/javascript">
document.addEventListener('touchmove', function (event) {
  if (event.scale !== 1) { event.preventDefault(); }
}, { passive: false });
</script>

Please Add the Script to Disable pinch, tap, focus Zoom

How can I do factory reset using adb in android?

You can send intent MASTER_CLEAR in adb:

adb shell am broadcast -a android.intent.action.MASTER_CLEAR

or as root

adb shell  "su -c 'am broadcast -a android.intent.action.MASTER_CLEAR'"

Passing multiple parameters to pool.map() function in Python

You can use functools.partial for this (as you suspected):

from functools import partial

def target(lock, iterable_item):
    for item in iterable_item:
        # Do cool stuff
        if (... some condition here ...):
            lock.acquire()
            # Write to stdout or logfile, etc.
            lock.release()

def main():
    iterable = [1, 2, 3, 4, 5]
    pool = multiprocessing.Pool()
    l = multiprocessing.Lock()
    func = partial(target, l)
    pool.map(func, iterable)
    pool.close()
    pool.join()

Example:

def f(a, b, c):
    print("{} {} {}".format(a, b, c))

def main():
    iterable = [1, 2, 3, 4, 5]
    pool = multiprocessing.Pool()
    a = "hi"
    b = "there"
    func = partial(f, a, b)
    pool.map(func, iterable)
    pool.close()
    pool.join()

if __name__ == "__main__":
    main()

Output:

hi there 1
hi there 2
hi there 3
hi there 4
hi there 5

HTML: how to force links to open in a new tab, not new window

Simply using "target=_blank" will respect the user/browser preference of whether to use a tab or a new window, which in most cases is "doing the right thing".

If you specify the dimensions of the new window, some browsers will use this as an indicator that a certain size is needed, in which case a new window will always be used. Stack overflow code example Stack Overflow

Am I trying to connect to a TLS-enabled daemon without TLS?

On Ubuntu after installing lxc-docker you need to add your user to the docker user group:

sudo usermod -a -G docker myusername

This is because of the socket file permissions:

srw-rw---- 1 root docker 0 Mar 20 07:43 /var/run/docker.sock

DO NOT RUN usermod WITHOUT "-a" as suggested in one of the other comments or it will wipe your additional groups setting and will just leave the "docker" group

This is what will happen:

?  ~  id pawel
uid=1000(pawel) gid=1000(pawel) groups=1000(pawel),4(adm),24(cdrom),27(sudo),30(dip),46(plugdev),108(lpadmin),124(sambashare),998(docker)
?  ~  usermod -G docker pawel
?  ~  id pawel               
uid=1000(pawel) gid=1000(pawel) groups=1000(pawel),998(docker)

OnClick Send To Ajax

Tried and working. you are using,

<textarea name='Status'> </textarea>
<input type='button' onclick='UpdateStatus()' value='Status Update'>

I am using javascript , (don't know about php), use id ="status" in textarea like

<textarea name='Status' id="status"> </textarea>
<input type='button' onclick='UpdateStatus()' value='Status Update'>

then make a call to servlet sending the status to backend for updating using whatever strutucre(like MVC in java or anyother) you like, like this in your UI in script tag

<srcipt>
function UpdateStatus(){

//make an ajax call and get status value using the same 'id'
var var1= document.getElementById("status").value;
$.ajax({

        type:"GET",//or POST
        url:'http://localhost:7080/ajaxforjson/Testajax',
                           //  (or whatever your url is)
        data:{data1:var1},
        //can send multipledata like {data1:var1,data2:var2,data3:var3
        //can use dataType:'text/html' or 'json' if response type expected 
        success:function(responsedata){
               // process on data
               alert("got response as "+"'"+responsedata+"'");

        }
     })

}
</script>

and jsp is like

the servlet will look like:   //webservlet("/zcvdzv") is just for url annotation
@WebServlet("/Testajax")

public class Testajax extends HttpServlet {
private static final long serialVersionUID = 1L;
public Testajax() {
    super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
    String data1=request.getParameter("data1");
    //do processing on datas pass in other java class to add to DB
    // i am adding or concatenate
    String data="i Got : "+"'"+data1+"' ";
    System.out.println(" data1 : "+data1+"\n data "+data);
    response.getWriter().write(data);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // TODO Auto-generated method stub
    doGet(request, response);
}

}

IF formula to compare a date with current date and return result

The formula provided by Blake doesn't seem to work for me. For past dates it returns due in xx days and for future dates, it returns overdue. Also, it will only return 15 days overdue, when it could actually be 30, 60 90+.

I created this, which seems to work and provides 'Due in xx days', 'Overdue xx days' and 'Due Today'.

=IF(ISBLANK(O10),"",IF(DAYS(TODAY(),O10)<0,CONCATENATE("Due in ",-DAYS(TODAY(),O10)," Days"),IF(DAYS(TODAY(),O10)>0,CONCATENATE("Overdue ",DAYS(TODAY(),O10)," Days"),"Due Today")))

How can I make my website's background transparent without making the content (images & text) transparent too?

I would agree with @evillinux, It would be best to make your background image semi transparent so it supports < ie8

The other suggestions of using another div are also a great option, and it's the way to go if you want to do this in css. For example if the site had such features as selecting your own background color. I would suggest using a filter for older IE. eg:

filter:Alpha(opacity=50)

JSONObject - How to get a value?

If it's a deeper key/value you're after and you're not dealing with arrays of keys/values at each level, you could recursively search the tree:

public static String recurseKeys(JSONObject jObj, String findKey) throws JSONException {
    String finalValue = "";
    if (jObj == null) {
        return "";
    }

    Iterator<String> keyItr = jObj.keys();
    Map<String, String> map = new HashMap<>();

    while(keyItr.hasNext()) {
        String key = keyItr.next();
        map.put(key, jObj.getString(key));
    }

    for (Map.Entry<String, String> e : (map).entrySet()) {
        String key = e.getKey();
        if (key.equalsIgnoreCase(findKey)) {
            return jObj.getString(key);
        }

        // read value
        Object value = jObj.get(key);

        if (value instanceof JSONObject) {
            finalValue = recurseKeys((JSONObject)value, findKey);
        }
    }

    // key is not found
    return finalValue;
}

Usage:

JSONObject jObj = new JSONObject(jsonString);
String extract = recurseKeys(jObj, "extract");

Using Map code from https://stackoverflow.com/a/4149555/2301224

Laravel, sync() - how to sync an array and also pass additional pivot fields?

In order to sync multiple models along with custom pivot data, you need this:

$user->roles()->sync([ 
    1 => ['expires' => true],
    2 => ['expires' => false],
    ...
]);

Ie.

sync([
    related_id => ['pivot_field' => value],
    ...
]);

edit

Answering the comment:

$speakers  = (array) Input::get('speakers'); // related ids
$pivotData = array_fill(0, count($speakers), ['is_speaker' => true]);
$syncData  = array_combine($speakers, $pivotData);

$user->roles()->sync($syncData);

How do I bind onchange event of a TextBox using JQuery?

You must change the event name from "change" to "onchange":

$(document).ready(function(){
        $("input#tags").bind("onchange", autoFill);
          });

or use the shortcut binder method change:

$(document).ready(function(){
        $("input#tags").change(autoFill);
          });

Note that the onchange event usually fires when the user leave the input, so for auto-complete you better use the keydown event.

ASP.NET MVC - Extract parameter of an URL

I'm not familiar with ASP.NET but I guess you could use a split function to split it in an array using the / as delimiter, then grab the last element in the array (usually the array length -1) to get the extract you want.

Ok this does not seem to work for all the examples.

What about a regex?

.*(/|[a-zA-Z]+\?)(.*)

then get that last subexpression (.*), I believe it's $+ in .Net, I'm not sure

Only detect click event on pseudo-element

This is edited answer by Fasoeu with latest CSS3 and JS ES6

Edited demo without using JQuery.

Shortest example of code:

<p><span>Some text</span></p>
p {
    position: relative;
    pointer-events: none;
}
p::before {
    content: "";
    position: absolute;
    pointer-events: auto;
}
p span {
    display: contents;
    pointer-events: auto;
}
const all_p = Array.from(document.querySelectorAll('p'));

for (let p of all_p) {
    p.addEventListener("click", listener, false);
};

Explanation:

pointer-events control detection of events, removing receiving events from target, but keep receiving from pseudo-elements make possible to click on ::before and ::after and you will always know what you are clicking on pseudo-element, however if you still need to click, you put all content in nested element (span in example), but because we don't want to apply any additional styles, display: contents; become very handy solution and it supported by most browsers. pointer-events: none; as already mentioned in original post also widely supported.

The JavaScript part also used widely supported Array.from and for...of, however they are not necessary to use in code.

SQL, Postgres OIDs, What are they and why are they useful?

OIDs basically give you a built-in id for every row, contained in a system column (as opposed to a user-space column). That's handy for tables where you don't have a primary key, have duplicate rows, etc. For example, if you have a table with two identical rows, and you want to delete the oldest of the two, you could do that using the oid column.

OIDs are implemented using 4-byte unsigned integers. They are not unique–OID counter will wrap around at 2³²-1. OID are also used to identify data types (see /usr/include/postgresql/server/catalog/pg_type_d.h).

In my experience, the feature is generally unused in most postgres-backed applications (probably in part because they're non-standard), and their use is essentially deprecated:

In PostgreSQL 8.1 default_with_oids is off by default; in prior versions of PostgreSQL, it was on by default.

The use of OIDs in user tables is considered deprecated, so most installations should leave this variable disabled. Applications that require OIDs for a particular table should specify WITH OIDS when creating the table. This variable can be enabled for compatibility with old applications that do not follow this behavior.

In Maven how to exclude resources from the generated jar?

Put those properties files in src/test/resources. Files in src/test/resources are available within Eclipse automatically via eclipse:eclipse but will not be included in the packaged JAR by Maven.

How to compare oldValues and newValues on React Hooks useEffect?

Using Ref will introduce a new kind of bug into the app.

Let's see this case using usePrevious that someone commented before:

  1. prop.minTime: 5 ==> ref.current = 5 | set ref.current
  2. prop.minTime: 5 ==> ref.current = 5 | new value is equal to ref.current
  3. prop.minTime: 8 ==> ref.current = 5 | new value is NOT equal to ref.current
  4. prop.minTime: 5 ==> ref.current = 5 | new value is equal to ref.current

As we can see here, we are not updating the internal ref because we are using useEffect

Get url parameters from a string in .NET

I used it and it run perfectly

<%=Request.QueryString["id"] %>

How do you Make A Repeat-Until Loop in C++?

do
{
  //  whatever
} while ( !condition );

How to run a function when the page is loaded?

window.onload will work like this:

_x000D_
_x000D_
function codeAddress() {_x000D_
 document.getElementById("test").innerHTML=Date();_x000D_
}_x000D_
window.onload = codeAddress;
_x000D_
<!DOCTYPE html>_x000D_
<html>_x000D_
<head>_x000D_
 <title>learning java script</title>_x000D_
 <script src="custom.js"></script>_x000D_
</head>_x000D_
<body>_x000D_
 <p id="test"></p>_x000D_
 <li>abcd</li>_x000D_
</body>_x000D_
</html>
_x000D_
_x000D_
_x000D_

Use getElementById on HTMLElement instead of HTMLDocument

Thanks to dee for the answer above with the Scrape() subroutine. The code worked perfectly as written, and I was able to then convert the code to work with the specific website I am trying to scrape.

I do not have enough reputation to upvote or to comment, but I do actually have some minor improvements to add to dee's answer:

  1. You will need to add the VBA Reference via "Tools\References" to "Microsoft HTML Object Library in order for the code to compile.

  2. I commented out the Browser.Visible line and added the comment as follows

    'if you need to debug the browser page, uncomment this line:
    'Browser.Visible = True
    
  3. And I added a line to close the browser before Set Browser = Nothing:

    Browser.Quit
    

Thanks again dee!

ETA: this works on machines with IE9, but not machines with IE8. Anyone have a fix?

Found the fix myself, so came back here to post it. The ClassName function is available in IE9. For this to work in IE8, you use querySelectorAll, with a dot preceding the class name of the object you are looking for:

'Set repList = doc.getElementsByClassName("reportList") 'only works in IE9, not in IE8
Set repList = doc.querySelectorAll(".reportList")       'this works in IE8+

Can Linux apps be run in Android?

Yes, they can. If you do not have a rooted phone/tablet, then you could download c4droid here to compile your apps. Then, you could download Kevin Boone's KBOX here to run the program.

How to escape special characters of a string with single backslashes

Simply using re.sub might also work instead of str.maketrans. And this would also work in python 2.x

>>> print(re.sub(r'(\-|\]|\^|\$|\*|\.|\\)',lambda m:{'-':'\-',']':'\]','\\':'\\\\','^':'\^','$':'\$','*':'\*','.':'\.'}[m.group()],"^stack.*/overflo\w$arr=1"))
\^stack\.\*/overflo\\w\$arr=1

Usage of the backtick character (`) in JavaScript

You can make a template of templates too, and reach private variable.

var a= {e:10, gy:'sfdsad'}; //global object

console.log(`e is ${a.e} and gy is ${a.gy}`); 
//e is 10 and gy is sfdsad

var b = "e is ${a.e} and gy is ${a.gy}" // template string
console.log( `${b}` );
//e is ${a.e} and gy is ${a.gy}

console.log( eval(`\`${b}\``) ); // convert template string to template
//e is 10 and gy is sfdsad

backtick( b );   // use fonction's variable
//e is 20 and gy is fghj

function backtick( temp ) {
  var a= {e:20, gy:'fghj'}; // local object
  console.log( eval(`\`${temp}\``) );
}

Change priorityQueue to max priorityqueue

You can use lambda expression since Java 8.

The following code will print 10, the larger.

// There is overflow problem when using simple lambda as comparator, as pointed out by ???? ?????.
// PriorityQueue<Integer> pq = new PriorityQueue<>((x, y) -> y - x);

PriorityQueue<Integer> pq =new PriorityQueue<>((x, y) -> Integer.compare(y, x));

pq.add(10);
pq.add(5);
System.out.println(pq.peek());

The lambda function will take two Integers as input parameters, subtract them from each other, and return the arithmetic result. The lambda function implements the Functional Interface, Comparator<T>. (This is used in place, as opposed to an anonymous class or a discrete implementation.)

PANIC: Cannot find AVD system path. Please define ANDROID_SDK_ROOT (in windows 10)

Try to use the argument: -sysdir <Your_SDK_DIR> and then check whether the error message displayed.

See also: https://android.googlesource.com/platform/external/qemu/+/1a15692cded92d66dea1a51389a3c4b9e3b3631a/android/emulator/main-emulator.cpp

Check out these clip you will find out the reason:

// Sanity checks.
if (avdName) {
    if (!isCpuArchSupportedByRanchu(avdArch)) {
        APANIC("CPU Architecture '%s' is not supported by the QEMU2 emulator, (the classic engine is deprecated!)",
               avdArch);
    }
    std::string systemPath = getAvdSystemPath(avdName, sysDir);
    if (systemPath.empty()) {
        const char* env = getenv("ANDROID_SDK_ROOT");
        if (!env || !env[0]) {
            APANIC("Cannot find AVD system path. Please define "
                   "ANDROID_SDK_ROOT\n");
        } else {
            APANIC("Broken AVD system path. Check your ANDROID_SDK_ROOT "
                   "value [%s]!\n",
                   env);
        }
    }
}

Then if you see emulator: ERROR: can't find SDK installation directory, please check this solution. Android emulator errors with "emulator: ERROR: can't find SDK installation directory"

Get the contents of a table row with a button click

Find element with id in row using jquery

$(document).ready(function () {
$("button").click(function() {
    //find content of different elements inside a row.
    var nameTxt = $(this).closest('tr').find('.name').text();
    var emailTxt = $(this).closest('tr').find('.email').text();
    //assign above variables text1,text2 values to other elements.
    $("#name").val( nameTxt );
    $("#email").val( emailTxt );
    });
});

Linux: is there a read or recv from socket with timeout?

LINUX

struct timeval tv;
tv.tv_sec = 30;        // 30 Secs Timeout
tv.tv_usec = 0;        // Not init'ing this can cause strange errors
setsockopt(sockfd, SOL_SOCKET, SO_RCVTIMEO, (const char*)&tv,sizeof(struct timeval));

WINDOWS

DWORD timeout = SOCKET_READ_TIMEOUT_SEC * 1000;
setsockopt(socket, SOL_SOCKET, SO_RCVTIMEO, (const char*)&timeout, sizeof(timeout));

NOTE: You have put this setting before bind() function call for proper run

Can’t delete docker image with dependent child images

When i want to remove some unused image with name "<none>" in docker i face with the problem unable to delete a354bbc7c9b7 (cannot be forced) - image has dependent child images.So for solving this problem:

sudo docker ps -a

CONTAINER ID        IMAGE                       COMMAND                  CREATED             STATUS                         PORTS                                              NAMES
01ee1276bbe0        lizard:1                    "/bin/sh -c 'java ..."   About an hour ago   Exited (1) About an hour ago                                                      objective_lewin
49d73d8fb023        javaapp:latest              "/usr/bin/java -ja..."   19 hours ago        Up 19 hours                    0.0.0.0:8091->8091/tcp                             pedantic_bell
405fd452c788        javaapp:latest              "/usr/bin/java -ja..."   19 hours ago        Created                                                                           infallible_varahamihira
532257a8b705        javaapp:latest              "/usr/bin/java -ja..."   19 hours ago        Created                                                                           demo-default
9807158b3fd5        javaapp:latest              "/usr/bin/java -ja..."   19 hours ago        Created                                                                           xenodochial_kilby
474930241afa        jenkins                     "/bin/tini -- /usr..."   13 days ago         Up 4 days                      0.0.0.0:8080->8080/tcp, 0.0.0.0:50000->50000/tcp   myjenkins
563d8c34682f        mysql/mysql-server:latest   "/entrypoint.sh my..."   3 weeks ago         Up 4 days (healthy)            0.0.0.0:3306->3306/tcp, 33060/tcp                  mymysql
b4ca73d45d20        phpmyadmin/phpmyadmin       "/run.sh phpmyadmin"     4 weeks ago         Exited (0) 3 weeks ago                                                            phpmyadmin

you can see that i have several Images with name javaapp:latest and different container name. So, i killed and remove all container of "javaapp:latest" container with:

sudo docker stop "containerName"

sudo docker rm "containrName"

Then

sudo docker rmi -f "imageId"

So i can remove all the images with name "<none>"

goodluck

How to read a line from the console in C?

A very simple but unsafe implementation to read line for static allocation:

char line[1024];

scanf("%[^\n]", line);

A safer implementation, without the possibility of buffer overflow, but with the possibility of not reading the whole line, is:

char line[1024];

scanf("%1023[^\n]", line);

Not the 'difference by one' between the length specified declaring the variable and the length specified in the format string. It is a historical artefact.

Difference between Grunt, NPM and Bower ( package.json vs bower.json )

Npm and Bower are both dependency management tools. But the main difference between both is npm is used for installing Node js modules but bower js is used for managing front end components like html, css, js etc.

A fact that makes this more confusing is that npm provides some packages which can be used in front-end development as well, like grunt and jshint.

These lines add more meaning

Bower, unlike npm, can have multiple files (e.g. .js, .css, .html, .png, .ttf) which are considered the main file(s). Bower semantically considers these main files, when packaged together, a component.

Edit: Grunt is quite different from Npm and Bower. Grunt is a javascript task runner tool. You can do a lot of things using grunt which you had to do manually otherwise. Highlighting some of the uses of Grunt:

  1. Zipping some files (e.g. zipup plugin)
  2. Linting on js files (jshint)
  3. Compiling less files (grunt-contrib-less)

There are grunt plugins for sass compilation, uglifying your javascript, copy files/folders, minifying javascript etc.

Please Note that grunt plugin is also an npm package.

Question-1

When I want to add a package (and check in the dependency into git), where does it belong - into package.json or into bower.json

It really depends where does this package belong to. If it is a node module(like grunt,request) then it will go in package.json otherwise into bower json.

Question-2

When should I ever install packages explicitly like that without adding them to the file that manages dependencies

It does not matter whether you are installing packages explicitly or mentioning the dependency in .json file. Suppose you are in the middle of working on a node project and you need another project, say request, then you have two options:

  • Edit the package.json file and add a dependency on 'request'
  • npm install

OR

  • Use commandline: npm install --save request

--save options adds the dependency to package.json file as well. If you don't specify --save option, it will only download the package but the json file will be unaffected.

You can do this either way, there will not be a substantial difference.

"Gradle Version 2.10 is required." Error

Important:

If you are getting this when you run:
gradle build
from command line you have to use:
gradlew build
instead so that you will use gradle wrapper to downloaded the appropriate gradle version needed by the app.

When you execute gradle build you are using the global gradle installed on your system.

How do you test running time of VBA code?

The Timer function in VBA gives you the number of seconds elapsed since midnight, to 1/100 of a second.

Dim t as single
t = Timer
'code
MsgBox Timer - t

excel VBA run macro automatically whenever a cell is changed

Yes, this is possible by using worksheet events:

In the Visual Basic Editor open the worksheet you're interested in (i.e. "BigBoard") by double clicking on the name of the worksheet in the tree at the top left. Place the following code in the module:

Private Sub Worksheet_Change(ByVal Target As Range)
    If Intersect(Target, Me.Range("D2")) Is Nothing Then Exit Sub
        Application.EnableEvents = False 'to prevent endless loop
        On Error Goto Finalize 'to re-enable the events      
        MsgBox "You changed THE CELL!"
    End If
Finalize:        
    Application.EnableEvents = True
End Sub

git - Server host key not cached

I have tried all the methods above but none of them could fix the same issue on my laptop. Finally instead of pushing the branch to origin in git bash, I trun to use TortoiseGit's push option to do the pushing, then a window pops-up to ask me to add the new host key to cache, after clicking the yes button, everything goes fine now.

Hope it helps to you all.

How to get JSON Key and Value?

First, I see you're using an explicit $.parseJSON(). If that's because you're manually serializing JSON on the server-side, don't. ASP.NET will automatically JSON-serialize your method's return value and jQuery will automatically deserialize it for you too.

To iterate through the first item in the array you've got there, use code like this:

var firstItem = response.d[0];

for(key in firstItem) {
  console.log(key + ':' + firstItem[key]);
}

If there's more than one item (it's hard to tell from that screenshot), then you can loop over response.d and then use this code inside that outer loop.

How can I execute Shell script in Jenkinsfile?

Previous answers are correct but here is one more way of doing this and some tips:

Option #1 Go to you Jenkins job and search for "add build step" and then just copy and paste your script there

Option #2 Go to Jenkins and do the same again "add build step" but this time put the fully qualified path for your script in there example : ./usr/somewhere/helloWorld.sh

enter image description here enter image description here

things to watch for /tips:

  • Environment variables, if your job is running at the same time then you need to worry about concurrency issues. One job may be setting the value of environment variables and the next may use the value or take some action based on that incorrectly.
  • Make sure all paths are fully qualified
  • Think about logging /var/log or somewhere so you would also have something to go to on the server (optional)
  • thing about space issue and permissions, running out of space and permission issues are very common in linux environment
  • Alerting and make sure your script/job fails the jenkin jobs when your script fails

Trigger css hover with JS

You can't. It's not a trusted event.

Events that are generated by the user agent, either as a result of user interaction, or as a direct result of changes to the DOM, are trusted by the user agent with privileges that are not afforded to events generated by script through the DocumentEvent.createEvent("Event") method, modified using the Event.initEvent() method, or dispatched via the EventTarget.dispatchEvent() method. The isTrusted attribute of trusted events has a value of true, while untrusted events have a isTrusted attribute value of false.

Most untrusted events should not trigger default actions, with the exception of click or DOMActivate events.

You have to add a class and add/remove that on the mouseover/mouseout events manually.


Side note, I'm answering this here after I marked this as a duplicate since no answer here really covers the issue from what I see. Hopefully, one day it'll be merged.

How to place a div on the right side with absolute position

For top right corner try this:

position: absolute;
top: 0;
right: 0;

How to upgrade OpenSSL in CentOS 6.5 / Linux / Unix from source?

To manually compile OpenSSL, do as follows:

$ cd /usr/src

$ wget https://www.openssl.org/source/openssl-1.0.1g.tar.gz -O openssl-1.0.1g.tar.gz

$ tar -zxf openssl-1.0.1g.tar.gz

$ cd openssl-1.0.1g

$ ./config

$ make

$ make test

$ make install

$ openssl version

If it shows the old version, do the steps below.

$ mv /usr/bin/openssl /root/

$ ln -s /usr/local/ssl/bin/openssl /usr/bin/openssl
openssl version
OpenSSL 1.0.1g 7 Apr 2014

http://olaitanmayowa.com/heartbleed-how-to-upgrade-openssl-in-centos/

$_SERVER["REMOTE_ADDR"] gives server IP rather than visitor IP

When using $_SERVER["REMOTE_ADDR"], I get the server's IP address rather than the visitor's.

Then something is wrong, or odd, with your configuration.

  • Are you using some sort of reverse proxy? In that case, @simshaun's suggestion may work.

  • Do you have anything else out of the ordinary in your web server config?

  • Can you show the PHP code you are using?

  • Can you show what the address looks like. Is it a local one, or a Internet address?

How to change the icon of an Android app in Eclipse?

Rob R.'s answer was definitely the way to go. I tried copying the ic_launcher.png files from another project and Eclipse still wouldn't read them. Going through the manifest is much quicker and easier.

Creating a triangle with for loops

First think of a solution without code. The idea is to print an odd number of *, increasing by line. Then center the * by using spaces. Knowing the max number of * in the last line, will give you the initial number of spaces to center the first *. Now write it in code.

Cannot access a disposed object - How to fix?

Stopping the timer doesn't mean that it won't be called again, depending on when you stop the timer, the timer_tick may still be queued on the message loop for the form. What will happen is that you'll get one more tick that you may not be expecting. What you can do is in your timer_tick, check the Enabled property of your timer before executing the Timer_Tick method.

Instantly detect client disconnection from server socket

Since there are no events available to signal when the socket is disconnected, you will have to poll it at a frequency that is acceptable to you.

Using this extension method, you can have a reliable method to detect if a socket is disconnected.

static class SocketExtensions
{
  public static bool IsConnected(this Socket socket)
  {
    try
    {
      return !(socket.Poll(1, SelectMode.SelectRead) && socket.Available == 0);
    }
    catch (SocketException) { return false; }
  }
}

Keeping session alive with Curl and PHP

This is how you do CURL with sessions

//initial request with login data

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'http://www.example.com/login.php');
curl_setopt($ch, CURLOPT_USERAGENT,'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/32.0.1700.107 Chrome/32.0.1700.107 Safari/537.36');
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, "username=XXXXX&password=XXXXX");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_COOKIESESSION, true);
curl_setopt($ch, CURLOPT_COOKIEJAR, 'cookie-name');  //could be empty, but cause problems on some hosts
curl_setopt($ch, CURLOPT_COOKIEFILE, '/var/www/ip4.x/file/tmp');  //could be empty, but cause problems on some hosts
$answer = curl_exec($ch);
if (curl_error($ch)) {
    echo curl_error($ch);
}

//another request preserving the session

curl_setopt($ch, CURLOPT_URL, 'http://www.example.com/profile');
curl_setopt($ch, CURLOPT_POST, false);
curl_setopt($ch, CURLOPT_POSTFIELDS, "");
$answer = curl_exec($ch);
if (curl_error($ch)) {
    echo curl_error($ch);
}

I've seen this on ImpressPages

HTML Table cell background image alignment

use like this your inline css

<td width="178" rowspan="3" valign="top" 
align="right" background="images/left.jpg" 
style="background-repeat:background-position: right top;">
</td>

How to remove items from a list while iterating?

The other answers are correct that it is usually a bad idea to delete from a list that you're iterating. Reverse iterating avoids the pitfalls, but it is much more difficult to follow code that does that, so usually you're better off using a list comprehension or filter.

There is, however, one case where it is safe to remove elements from a sequence that you are iterating: if you're only removing one item while you're iterating. This can be ensured using a return or a break. For example:

for i, item in enumerate(lst):
    if item % 4 == 0:
        foo(item)
        del lst[i]
        break

This is often easier to understand than a list comprehension when you're doing some operations with side effects on the first item in a list that meets some condition and then removing that item from the list immediately after.

Get a specific bit from byte

[Flags]
enum Relays : byte
{
    relay0 = 1 << 0,
    relay1 = 1 << 1,
    relay2 = 1 << 2,
    relay3 = 1 << 3,
    relay4 = 1 << 4,
    relay5 = 1 << 5,
    relay6 = 1 << 6,
    relay7 = 1 << 7
}

public static bool GetRelay(byte b, Relays relay)
{
    return (Relays)b.HasFlag(relay);
}

Send POST data via raw json with postman

Unlike jQuery in order to read raw JSON you will need to decode it in PHP.

print_r(json_decode(file_get_contents("php://input"), true));

php://input is a read-only stream that allows you to read raw data from the request body.

$_POST is form variables, you will need to switch to form radiobutton in postman then use:

foo=bar&foo2=bar2

To post raw json with jquery:

$.ajax({
    "url": "/rest/index.php",
    'data': JSON.stringify({foo:'bar'}),
    'type': 'POST',
    'contentType': 'application/json'
});

Laravel Eloquent update just if changes have been made

You're already doing it!

save() will check if something in the model has changed. If it hasn't it won't run a db query.

Here's the relevant part of code in Illuminate\Database\Eloquent\Model@performUpdate:

protected function performUpdate(Builder $query, array $options = [])
{
    $dirty = $this->getDirty();

    if (count($dirty) > 0)
    {
        // runs update query
    }

    return true;
}

The getDirty() method simply compares the current attributes with a copy saved in original when the model is created. This is done in the syncOriginal() method:

public function __construct(array $attributes = array())
{
    $this->bootIfNotBooted();

    $this->syncOriginal();

    $this->fill($attributes);
}

public function syncOriginal()
{
    $this->original = $this->attributes;

    return $this;
}

If you want to check if the model is dirty just call isDirty():

if($product->isDirty()){
    // changes have been made
}

Or if you want to check a certain attribute:

if($product->isDirty('price')){
    // price has changed
}

[] and {} vs list() and dict(), which is better?

In terms of speed, it's no competition for empty lists/dicts:

>>> from timeit import timeit
>>> timeit("[]")
0.040084982867934334
>>> timeit("list()")
0.17704233359267718
>>> timeit("{}")
0.033620194745424214
>>> timeit("dict()")
0.1821558326547077

and for non-empty:

>>> timeit("[1,2,3]")
0.24316302770330367
>>> timeit("list((1,2,3))")
0.44744206316727286
>>> timeit("list(foo)", setup="foo=(1,2,3)")
0.446036018543964
>>> timeit("{'a':1, 'b':2, 'c':3}")
0.20868602015059423
>>> timeit("dict(a=1, b=2, c=3)")
0.47635635255323905
>>> timeit("dict(bar)", setup="bar=[('a', 1), ('b', 2), ('c', 3)]")
0.9028228448029267

Also, using the bracket notation lets you use list and dictionary comprehensions, which may be reason enough.

Display animated GIF in iOS

If you are targeting iOS7 and already have the image split into frames you can use animatedImageNamed:duration:.

Let's say you are animating a spinner. Copy all of your frames into the project and name them as follows:

  • spinner-1.png
  • spinner-2.png
  • spinner-3.png
  • etc.,

Then create the image via:

[UIImage animatedImageNamed:@"spinner-" duration:1.0f];

From the docs:

This method loads a series of files by appending a series of numbers to the base file name provided in the name parameter. For example, if the name parameter had ‘image’ as its contents, this method would attempt to load images from files with the names ‘image0’, ‘image1’ and so on all the way up to ‘image1024’. All images included in the animated image should share the same size and scale.

Algorithm: efficient way to remove duplicate integers from an array

Insert all the elements in a binary tree the disregards duplicates - O(nlog(n)). Then extract all of them back in the array by doing a traversal - O(n). I am assuming that you don't need order preservation.

How do I download a file with Angular2 or greater

For those using Redux Pattern

I added in the file-saver as @Hector Cuevas named in his answer. Using Angular2 v. 2.3.1, I didn't need to add in the @types/file-saver.

The following example is to download a journal as PDF.

The journal actions

public static DOWNLOAD_JOURNALS = '[Journals] Download as PDF';
public downloadJournals(referenceId: string): Action {
 return {
   type: JournalActions.DOWNLOAD_JOURNALS,
   payload: { referenceId: referenceId }
 };
}

public static DOWNLOAD_JOURNALS_SUCCESS = '[Journals] Download as PDF Success';
public downloadJournalsSuccess(blob: Blob): Action {
 return {
   type: JournalActions.DOWNLOAD_JOURNALS_SUCCESS,
   payload: { blob: blob }
 };
}

The journal effects

@Effect() download$ = this.actions$
    .ofType(JournalActions.DOWNLOAD_JOURNALS)
    .switchMap(({payload}) =>
        this._journalApiService.downloadJournal(payload.referenceId)
        .map((blob) => this._actions.downloadJournalsSuccess(blob))
        .catch((err) => handleError(err, this._actions.downloadJournalsFail(err)))
    );

@Effect() downloadJournalSuccess$ = this.actions$
    .ofType(JournalActions.DOWNLOAD_JOURNALS_SUCCESS)
    .map(({payload}) => saveBlobAs(payload.blob, 'journal.pdf'))

The journal service

public downloadJournal(referenceId: string): Observable<any> {
    const url = `${this._config.momentumApi}/api/journals/${referenceId}/download`;
    return this._http.getBlob(url);
}

The HTTP service

public getBlob = (url: string): Observable<any> => {
    return this.request({
        method: RequestMethod.Get,
        url: url,
        responseType: ResponseContentType.Blob
    });
};

The journal reducer Though this only sets the correct states used in our application I still wanted to add it in to show the complete pattern.

case JournalActions.DOWNLOAD_JOURNALS: {
  return Object.assign({}, state, <IJournalState>{ downloading: true, hasValidationErrors: false, errors: [] });
}

case JournalActions.DOWNLOAD_JOURNALS_SUCCESS: {
  return Object.assign({}, state, <IJournalState>{ downloading: false, hasValidationErrors: false, errors: [] });
}

I hope this is helpful.

Terminating idle mysql connections

Manual cleanup:

You can KILL the processid.

mysql> show full processlist;
+---------+------------+-------------------+------+---------+-------+-------+-----------------------+
| Id      | User       | Host              | db   | Command | Time  | State | Info                  |
+---------+------------+-------------------+------+---------+-------+-------+-----------------------+
| 1193777 | TestUser12 | 192.168.1.11:3775 | www  | Sleep   | 25946 |       | NULL                  |
+---------+------------+-------------------+------+---------+-------+-------+-----------------------+

mysql> kill 1193777;

But:

  • the php application might report errors (or the webserver, check the error logs)
  • don't fix what is not broken - if you're not short on connections, just leave them be.

Automatic cleaner service ;)

Or you configure your mysql-server by setting a shorter timeout on wait_timeout and interactive_timeout

mysql> show variables like "%timeout%";
+--------------------------+-------+
| Variable_name            | Value |
+--------------------------+-------+
| connect_timeout          | 5     |
| delayed_insert_timeout   | 300   |
| innodb_lock_wait_timeout | 50    |
| interactive_timeout      | 28800 |
| net_read_timeout         | 30    |
| net_write_timeout        | 60    |
| slave_net_timeout        | 3600  |
| table_lock_wait_timeout  | 50    |
| wait_timeout             | 28800 |
+--------------------------+-------+
9 rows in set (0.00 sec)

Set with:

set global wait_timeout=3;
set global interactive_timeout=3;

(and also set in your configuration file, for when your server restarts)

But you're treating the symptoms instead of the underlying cause - why are the connections open? If the PHP script finished, shouldn't they close? Make sure your webserver is not using connection pooling...

Integer expression expected error in shell script

Try this:

If [ $a -lt 4 ] || [ $a -gt 64 ] ; then \n
     Something something \n
elif [ $a -gt 4 ] || [ $a -lt 64 ] ; then \n
     Something something \n
else \n
    Yes it works for me :) \n

Is `shouldOverrideUrlLoading` really deprecated? What can I use instead?

Use

public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
    return shouldOverrideUrlLoading(view, request.getUrl().toString());
}

Using Auto Layout in UITableView for dynamic cell layouts & variable row heights

In my case, the padding was because of the sectionHeader and sectionFooter heights, where storyboard allowed me to change it to minimum 1. So in viewDidLoad method:

tableView.sectionHeaderHeight = 0
tableView.sectionFooterHeight = 0

Why does C++ code for testing the Collatz conjecture run faster than hand-written assembly?

From comments:

But, this code never stops (because of integer overflow) !?! Yves Daoust

For many numbers it will not overflow.

If it will overflow - for one of those unlucky initial seeds, the overflown number will very likely converge toward 1 without another overflow.

Still this poses interesting question, is there some overflow-cyclic seed number?

Any simple final converging series starts with power of two value (obvious enough?).

2^64 will overflow to zero, which is undefined infinite loop according to algorithm (ends only with 1), but the most optimal solution in answer will finish due to shr rax producing ZF=1.

Can we produce 2^64? If the starting number is 0x5555555555555555, it's odd number, next number is then 3n+1, which is 0xFFFFFFFFFFFFFFFF + 1 = 0. Theoretically in undefined state of algorithm, but the optimized answer of johnfound will recover by exiting on ZF=1. The cmp rax,1 of Peter Cordes will end in infinite loop (QED variant 1, "cheapo" through undefined 0 number).

How about some more complex number, which will create cycle without 0? Frankly, I'm not sure, my Math theory is too hazy to get any serious idea, how to deal with it in serious way. But intuitively I would say the series will converge to 1 for every number : 0 < number, as the 3n+1 formula will slowly turn every non-2 prime factor of original number (or intermediate) into some power of 2, sooner or later. So we don't need to worry about infinite loop for original series, only overflow can hamper us.

So I just put few numbers into sheet and took a look on 8 bit truncated numbers.

There are three values overflowing to 0: 227, 170 and 85 (85 going directly to 0, other two progressing toward 85).

But there's no value creating cyclic overflow seed.

Funnily enough I did a check, which is the first number to suffer from 8 bit truncation, and already 27 is affected! It does reach value 9232 in proper non-truncated series (first truncated value is 322 in 12th step), and the maximum value reached for any of the 2-255 input numbers in non-truncated way is 13120 (for the 255 itself), maximum number of steps to converge to 1 is about 128 (+-2, not sure if "1" is to count, etc...).

Interestingly enough (for me) the number 9232 is maximum for many other source numbers, what's so special about it? :-O 9232 = 0x2410 ... hmmm.. no idea.

Unfortunately I can't get any deep grasp of this series, why does it converge and what are the implications of truncating them to k bits, but with cmp number,1 terminating condition it's certainly possible to put the algorithm into infinite loop with particular input value ending as 0 after truncation.

But the value 27 overflowing for 8 bit case is sort of alerting, this looks like if you count the number of steps to reach value 1, you will get wrong result for majority of numbers from the total k-bit set of integers. For the 8 bit integers the 146 numbers out of 256 have affected series by truncation (some of them may still hit the correct number of steps by accident maybe, I'm too lazy to check).

What is the difference between <section> and <div>?

The section tag provides a more semantic syntax for html. div is a generic tag for a section. When you use section tag for appropriate content, it can be used for search engine optimization also. section tag also makes it easy for html parsing. for more info, refer. http://blog.whatwg.org/is-not-just-a-semantic

How to Toggle a div's visibility by using a button click

Bootstrap 4 provides the Collapse component for that. It's using JavaScript behind the scenes, but you don't have to write any JavaScript yourself.

This feature works for <button> and <a>.

If you use a <button>, you must set the data-toggle and data-target attributes:

<button type="button" data-toggle="collapse" data-target="#collapseExample">
  Toggle
</button>
<div class="collapse" id="collapseExample">
  Lorem ipsum
</div>

If you use a <a>, you must use set href and data-toggle:

<a data-toggle="collapse" href="#collapseExample">
  Toggle
</a>
<div class="collapse" id="collapseExample">
  Lorem ipsum
</div>

Opening a CHM file produces: "navigation to the webpage was canceled"

I fixed this programmatically in my software, using C++ Builder.

Before I assign the CHM help file, Application->HelpFile = HelpFileName, I check to see if it contains the "Zone.Identifier" stream, and when it does, I simply remove it.

String ZIStream(HelpFileName + ":Zone.Identifier") ;

if (FileExists(ZIStream))
    { DeleteFile(ZIStream) ; }

String to LocalDate

As you use Joda Time, you should use DateTimeFormatter:

final DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyy-MMM-dd");
final LocalDate dt = dtf.parseLocalDate(yourinput);

If using Java 8 or later, then refer to hertzi's answer

How to save final model using keras?

you can save the model in json and weights in a hdf5 file format.

# keras library import  for Saving and loading model and weights

from keras.models import model_from_json
from keras.models import load_model

# serialize model to JSON
#  the keras model which is trained is defined as 'model' in this example
model_json = model.to_json()


with open("model_num.json", "w") as json_file:
    json_file.write(model_json)

# serialize weights to HDF5
model.save_weights("model_num.h5")

files "model_num.h5" and "model_num.json" are created which contain our model and weights

To use the same trained model for further testing you can simply load the hdf5 file and use it for the prediction of different data. here's how to load the model from saved files.

# load json and create model
json_file = open('model_num.json', 'r')

loaded_model_json = json_file.read()
json_file.close()
loaded_model = model_from_json(loaded_model_json)

# load weights into new model
loaded_model.load_weights("model_num.h5")
print("Loaded model from disk")

loaded_model.save('model_num.hdf5')
loaded_model=load_model('model_num.hdf5')

To predict for different data you can use this

loaded_model.predict_classes("your_test_data here")

Genymotion, "Unable to load VirtualBox engine." on Mavericks. VBox is setup correctly

I had the same problem and solved it by running the following command:

sudo /Library/StartupItems/VirtualBox/VirtualBox restart

In later versions, the command is

sudo /Library/Application\ Support/VirtualBox/LaunchDaemons/VirtualBoxStartup.sh restart

Make sure you've unblocked VirtualBox's kernel extensions in System Preferences->Security and Privacy->General (You'll get a popup when you install VirtualBox).

Where can I download english dictionary database in a text format?

The Gutenberg Project hosts Webster's Unabridged English Dictionary plus many other public domain literary works. Actually it looks like they've got several versions of the dictionary hosted with copyright from different years. The one I linked has a 2009 copyright. You may want to poke around the site and investigate the different versions of Webster's dictionary.

VB.Net: Dynamically Select Image from My.Resources

Make sure you don't include extension of the resource, nor path to it. It's only the resource file name.

PictureBoxName.Image = My.Resources.ResourceManager.GetObject("object_name") 

DateTime "null" value

Just be warned - When using a Nullable its obviously no longer a 'pure' datetime object, as such you cannot access the DateTime members directly. I'll try and explain.

By using Nullable<> you're basically wrapping DateTime in a container (thank you generics) of which is nullable - obviously its purpose. This container has its own properties which you can call that will provide access to the aforementioned DateTime object; after using the correct property - in this case Nullable.Value - you then have access to the standard DateTime members, properties etc.

So - now the issue comes to mind as to the best way to access the DateTime object. There are a few ways, number 1 is by FAR the best and 2 is "dude why".

  1. Using the Nullable.Value property,

    DateTime date = myNullableObject.Value.ToUniversalTime(); //Works

    DateTime date = myNullableObject.ToUniversalTime(); //Not a datetime object, fails

  2. Converting the nullable object to datetime using Convert.ToDateTime(),

    DateTime date = Convert.ToDateTime(myNullableObject).ToUniversalTime(); //works but why...

Although the answer is well documented at this point, I believe the usage of Nullable was probably worth posting about. Sorry if you disagree.

edit: Removed a third option as it was a bit overly specific and case dependent.

Using File.listFiles with FileNameExtensionFilter

The FileNameExtensionFilter class is intended for Swing to be used in a JFileChooser.

Try using a FilenameFilter instead. For example:

File dir = new File("/users/blah/dirname");
File[] files = dir.listFiles(new FilenameFilter() {
    public boolean accept(File dir, String name) {
        return name.toLowerCase().endsWith(".txt");
    }
});

How to change the interval time on bootstrap carousel?

The best way to get rid on it is adding or modifying the data-interval attribute like this:

<div data-ride="carousel" class="carousel slide" data-interval="10000" id="myCarousel">

It's specified on ms like it's usually on js, so 1000 = 1s, 3000 = 3s... 10000 = 10s.

By the way you can also specify it at 0 for not sliding automatically. It's useful when showing product images on mobile for example.

<div data-ride="carousel" class="carousel slide" data-interval="0" id="myCarousel">

XPath to get all child nodes (elements, comments, and text) without parent

From the documentation of XPath ( http://www.w3.org/TR/xpath/#location-paths ):

child::* selects all element children of the context node

child::text() selects all text node children of the context node

child::node() selects all the children of the context node, whatever their node type

So I guess your answer is:

$doc/PRESENTEDIN/X/child::node()

And if you want a flatten array of all nested nodes:

$doc/PRESENTEDIN/X/descendant::node()

How to recover just deleted rows in mysql?

As Mitch mentioned, backing data up is the best method.

However, it maybe possible to extract the lost data partially depending on the situation or DB server used. For most part, you are out of luck if you don't have any backup.

What svn command would list all the files modified on a branch?

This will list only modified files:

svn status -u | grep M

Running code in main thread from another thread

I know this is an old question, but I came across a main thread one-liner that I use in both Kotlin and Java. This may not be the best solution for a service, but for calling something that will change the UI inside of a fragment this is extremely simple and obvious.

Java (8):

 getActivity().runOnUiThread(()->{
      //your main thread code
 });

Kotlin:

this.runOnUiThread {
     //your main thread code
}

Can't use modulus on doubles?

The % operator is for integers. You're looking for the fmod() function.

#include <cmath>

int main()
{
    double x = 6.3;
    double y = 2.0;
    double z = std::fmod(x,y);

}

javax.net.ssl.SSLException: Received fatal alert: protocol_version

I ran into this issue while trying to install a PySpark package. I got around the issue by changing the TLS version with an environment variable:

echo 'export JAVA_TOOL_OPTIONS="-Dhttps.protocols=TLSv1.2"' >> ~/.bashrc
source ~/.bashrc

no overload for matches delegate 'system.eventhandler'

Change the klik method as follows:

public void klik(object pea, EventArgs e)
{
    Bitmap c = this.DrawMandel();
    Button btn = pea as Button;
    Graphics gr = btn.CreateGraphics();
    gr.DrawImage(b, 150, 200);
}

Update using LINQ to SQL

 DataClassesDataContext dc = new DataClassesDataContext();

 FamilyDetail fd = dc.FamilyDetails.Single(p => p.UserId == 1);

 fd.FatherName=txtFatherName.Text;
        fd.FatherMobile=txtMobile.Text;
        fd.FatherOccupation=txtFatherOccu.Text;
        fd.MotherName=txtMotherName.Text;
        fd.MotherOccupation=txtMotherOccu.Text;
        fd.Phone=txtPhoneNo.Text;
        fd.Address=txtAddress.Text;
        fd.GuardianName=txtGardianName.Text;

        dc.SubmitChanges();

Retrieve specific commit from a remote Git repository

If the requested commit is in the pull requests of the remote repo, you can get it by its ID:

# Add the remote repo path, let's call it 'upstream':
git remote add upstream https://github.com/repo/project.git

# checkout the pull ID, for example ID '60':
git fetch upstream pull/60/head && git checkout FETCH_HEAD

Way to run Excel macros from command line or batch file?

Instead of directly comparing the strings (VB won't find them equal since GetEnvironmentVariable returns a string of length 255) write this:

Private Sub Workbook_Open()     
    If InStr(1, GetEnvironmentVariable("InBatch"), "TRUE", vbTextCompare) Then
        Debug.Print "Batch"  
        Call Macro
    Else    
        Debug.Print "Normal"     
    End If 

End Sub 

Limiting number of displayed results when using ngRepeat

Use limitTo filter to display a limited number of results in ng-repeat.

<ul class="phones">
      <li ng-repeat="phone in phones | limitTo:5">
        {{phone.name}}
        <p>{{phone.snippet}}</p>
      </li>
</ul>

How to get a .csv file into R?

You need read.csv("C:/somedirectory/some/file.csv") and in general it doesn't hurt to actually look at the help page including its example section at the bottom.

Why isn't ProjectName-Prefix.pch created automatically in Xcode 6?

You need to create own PCH file
Add New file -> Other-> PCH file

Then add the path of this PCH file to your build setting->prefix header->path

($(SRCROOT)/filename.pch)

enter image description here

Restricting JTextField input to Integers

I used to use the Key Listener for this but I failed big time with that approach. Best approach as recommended already is to use a DocumentFilter. Below is a utility method I created for building textfields with only number input. Just beware that it'll also take single '.' character as well since it's usable for decimal input.

public static void installNumberCharacters(AbstractDocument document) {
        document.setDocumentFilter(new DocumentFilter() {
            @Override
            public void insertString(FilterBypass fb, int offset,
                    String string, AttributeSet attr)
                    throws BadLocationException {
                try {
                    if (string.equals(".")
                            && !fb.getDocument()
                                    .getText(0, fb.getDocument().getLength())
                                    .contains(".")) {
                        super.insertString(fb, offset, string, attr);
                        return;
                    }
                    Double.parseDouble(string);
                    super.insertString(fb, offset, string, attr);
                } catch (Exception e) {
                    Toolkit.getDefaultToolkit().beep();
                }

            }

            @Override
            public void replace(FilterBypass fb, int offset, int length,
                    String text, AttributeSet attrs)
                    throws BadLocationException {
                try {
                    if (text.equals(".")
                            && !fb.getDocument()
                                    .getText(0, fb.getDocument().getLength())
                                    .contains(".")) {
                        super.insertString(fb, offset, text, attrs);
                        return;
                    }
                    Double.parseDouble(text);
                    super.replace(fb, offset, length, text, attrs);
                } catch (Exception e) {
                    Toolkit.getDefaultToolkit().beep();
                }
            }
        });
    }

How can I check if an InputStream is empty without reading from it?

How about using inputStreamReader.ready() to find out?

import java.io.InputStreamReader;

/// ...

InputStreamReader reader = new InputStreamReader(inputStream);
if (reader.ready()) {
    // do something
}

// ...

Is there a bash command which counts files?

You can use the -R option to find the files along with those inside the recursive directories

ls -R | wc -l // to find all the files

ls -R | grep log | wc -l // to find the files which contains the word log

you can use patterns on the grep

Histogram using gnuplot?

I have found this discussion extremely useful, but I have experienced some "rounding off" problems.

More precisely, using a binwidth of 0.05, I have noticed that, with the techniques presented here above, data points which read 0.1 and 0.15 fall in the same bin. This (obviously unwanted behaviour) is most likely due to the "floor" function.

Hereafter is my small contribution to try to circumvent this.

bin(x,width,n)=x<=n*width? width*(n-1) + 0.5*binwidth:bin(x,width,n+1)
binwidth = 0.05
set boxwidth binwidth
plot "data.dat" u (bin($1,binwidth,1)):(1.0) smooth freq with boxes

This recursive method is for x >=0; one could generalise this with more conditional statements to obtain something even more general.

Get Multiple Values in SQL Server Cursor

This should work:

DECLARE db_cursor CURSOR FOR SELECT name, age, color FROM table; 
DECLARE @myName VARCHAR(256);
DECLARE @myAge INT;
DECLARE @myFavoriteColor VARCHAR(40);
OPEN db_cursor;
FETCH NEXT FROM db_cursor INTO @myName, @myAge, @myFavoriteColor;
WHILE @@FETCH_STATUS = 0  
BEGIN  

       --Do stuff with scalar values

       FETCH NEXT FROM db_cursor INTO @myName, @myAge, @myFavoriteColor;
END;
CLOSE db_cursor;
DEALLOCATE db_cursor;

What are the performance characteristics of sqlite with very large database files?

We are using DBS of 50 GB+ on our platform. no complains works great. Make sure you are doing everything right! Are you using predefined statements ? *SQLITE 3.7.3

  1. Transactions
  2. Pre made statements
  3. Apply these settings (right after you create the DB)

    PRAGMA main.page_size = 4096;
    PRAGMA main.cache_size=10000;
    PRAGMA main.locking_mode=EXCLUSIVE;
    PRAGMA main.synchronous=NORMAL;
    PRAGMA main.journal_mode=WAL;
    PRAGMA main.cache_size=5000;
    

Hope this will help others, works great here

How to concatenate characters in java?

System.out.print(a + "" + b + "" + c);

"inconsistent use of tabs and spaces in indentation"

If you use ATOM:

Go to Menu: Packages --> WhiteSpace --> Convert all Tabs to Spaces

Most efficient method to groupby on an array of objects

Posting because even though this question is 7 years old, I have yet to see an answer that satisfies the original criteria:

I don’t want them “split up” but “merged”, more like the SQL group by method.

I originally came to this post because I wanted to find a method of reducing an array of objects (i.e., the data structure created when you read from a csv, for example) and aggregate by given indices to produce the same data structure. The return value I was looking for was another array of objects, not a nested object or map like I've seen proposed here.

The following function takes a dataset (array of objects), a list of indices (array), and a reducer function, and returns the result of applying the reducer function on the indices as an array of objects.

function agg(data, indices, reducer) {

  // helper to create unique index as an array
  function getUniqueIndexHash(row, indices) {
    return indices.reduce((acc, curr) => acc + row[curr], "");
  }

  // reduce data to single object, whose values will be each of the new rows
  // structure is an object whose values are arrays
  // [{}] -> {{}}
  // no operation performed, simply grouping
  let groupedObj = data.reduce((acc, curr) => {
    let currIndex = getUniqueIndexHash(curr, indices);

    // if key does not exist, create array with current row
    if (!Object.keys(acc).includes(currIndex)) {
      acc = {...acc, [currIndex]: [curr]}
    // otherwise, extend the array at currIndex
    } else {
      acc = {...acc, [currIndex]: acc[currIndex].concat(curr)};
    }

    return acc;
  }, {})

  // reduce the array into a single object by applying the reducer
  let reduced = Object.values(groupedObj).map(arr => {
    // for each sub-array, reduce into single object using the reducer function
    let reduceValues = arr.reduce(reducer, {});

    // reducer returns simply the aggregates - add in the indices here
    // each of the objects in "arr" has the same indices, so we take the first
    let indexObj = indices.reduce((acc, curr) => {
      acc = {...acc, [curr]: arr[0][curr]};
      return acc;
    }, {});

    reduceValues = {...indexObj, ...reduceValues};


    return reduceValues;
  });


  return reduced;
}

I'll create a reducer that returns count(*) and sum(Value):

reducer = (acc, curr) => {
  acc.count = 1 + (acc.count || 0);
  acc.value = +curr.Value + (acc.value|| 0);
  return acc;
}

finally, applying the agg function with our reducer to the original dataset yields an array of objects with the appropriate aggregations applied:

agg(tasks, ["Phase"], reducer);
// yields:
Array(2) [
  0: Object {Phase: "Phase 1", count: 4, value: 50}
  1: Object {Phase: "Phase 2", count: 4, value: 130}
]

agg(tasks, ["Phase", "Step"], reducer);
// yields:
Array(4) [
  0: Object {Phase: "Phase 1", Step: "Step 1", count: 2, value: 15}
  1: Object {Phase: "Phase 1", Step: "Step 2", count: 2, value: 35}
  2: Object {Phase: "Phase 2", Step: "Step 1", count: 2, value: 55}
  3: Object {Phase: "Phase 2", Step: "Step 2", count: 2, value: 75}
]

Android Webview - Completely Clear the Cache

context.deleteDatabase("webview.db");
context.deleteDatabase("webviewCache.db")

Did the trick

How to get position of a certain element in strings vector, to use it as an index in ints vector?

I am a beginner so here is a beginners answer. The if in the for loop gives i which can then be used however needed such as Numbers[i] in another vector. Most is fluff for examples sake, the for/if really says it all.

int main(){
vector<string>names{"Sara", "Harold", "Frank", "Taylor", "Sasha", "Seymore"};
string req_name;
cout<<"Enter search name: "<<'\n';
cin>>req_name;
    for(int i=0; i<=names.size()-1; ++i) {
        if(names[i]==req_name){
            cout<<"The index number for "<<req_name<<" is "<<i<<'\n';
            return 0;
        }
        else if(names[i]!=req_name && i==names.size()-1) {
            cout<<"That name is not an element in this vector"<<'\n';
        } else {
            continue;
        }
    }

Remove/ truncate leading zeros by javascript/jquery

Maybe a little late, but I want to add my 2 cents.

if your string ALWAYS represents a number, with possible leading zeros, you can simply cast the string to a number by using the '+' operator.

e.g.

x= "00005";
alert(typeof x); //"string"
alert(x);// "00005"

x = +x ; //or x= +"00005"; //do NOT confuse with x+=x, which will only concatenate the value
alert(typeof x); //number , voila!
alert(x); // 5 (as number)

if your string doesn't represent a number and you only need to remove the 0's use the other solutions, but if you only need them as number, this is the shortest way.

and FYI you can do the opposite, force numbers to act as strings if you concatenate an empty string to them, like:

x = 5;
alert(typeof x); //number
x = x+"";
alert(typeof x); //string

hope it helps somebody

When would you use the different git merge strategies?

I'm not familiar with resolve, but I've used the others:

Recursive

Recursive is the default for non-fast-forward merges. We're all familiar with that one.

Octopus

I've used octopus when I've had several trees that needed to be merged. You see this in larger projects where many branches have had independent development and it's all ready to come together into a single head.

An octopus branch merges multiple heads in one commit as long as it can do it cleanly.

For illustration, imagine you have a project that has a master, and then three branches to merge in (call them a, b, and c).

A series of recursive merges would look like this (note that the first merge was a fast-forward, as I didn't force recursion):

series of recursive merges

However, a single octopus merge would look like this:

commit ae632e99ba0ccd0e9e06d09e8647659220d043b9
Merge: f51262e... c9ce629... aa0f25d...

octopus merge

Ours

Ours == I want to pull in another head, but throw away all of the changes that head introduces.

This keeps the history of a branch without any of the effects of the branch.

(Read: It is not even looked at the changes between those branches. The branches are just merged and nothing is done to the files. If you want to merge in the other branch and every time there is the question "our file version or their version" you can use git merge -X ours)

Subtree

Subtree is useful when you want to merge in another project into a subdirectory of your current project. Useful when you have a library you don't want to include as a submodule.

Animate element transform rotate

I stumbled upon this post, looking to use CSS transform in jQuery for an infinite loop animation. This one worked fine for me. I don't know how professional it is though.

function progressAnim(e) {
    var ang = 0;

    setInterval(function () {
        ang += 3;
        e.css({'transition': 'all 0.01s linear',
        'transform': 'rotate(' + ang + 'deg)'});
    }, 10);
}

Example of using:

var animated = $('#elem');
progressAnim(animated)

visual c++: #include files from other projects in the same solution

Settings for compiler

In the project where you want to #include the header file from another project, you will need to add the path of the header file into the Additional Include Directories section in the project configuration.

To access the project configuration:

  1. Right-click on the project, and select Properties.
  2. Select Configuration Properties->C/C++->General.
  3. Set the path under Additional Include Directories.

How to include

To include the header file, simply write the following in your code:

#include "filename.h"

Note that you don't need to specify the path here, because you include the directory in the Additional Include Directories already, so Visual Studio will know where to look for it.

If you don't want to add every header file location in the project settings, you could just include a directory up to a point, and then #include relative to that point:

// In project settings
Additional Include Directories    ..\..\libroot

// In code
#include "lib1/lib1.h"    // path is relative to libroot
#include "lib2/lib2.h"    // path is relative to libroot

Setting for linker

If using static libraries (i.e. .lib file), you will also need to add the library to the linker input, so that at linkage time the symbols can be linked against (otherwise you'll get an unresolved symbol):

  1. Right-click on the project, and select Properties.
  2. Select Configuration Properties->Linker->Input
  3. Enter the library under Additional Dependencies.

Eclipse Intellisense?

You don't have to press CTRL * space but maybe the delay is too big or you don't like the trigger (default is '.'). Go to

Window -> Preferences -> Java/Editor/Content Assist

And change the settings under Auto Activation to your likings.

If this does not work for windows users then see this answer.

How to execute command stored in a variable?

Unix shells operate a series of transformations on each line of input before executing them. For most shells it looks something like this (taken from the bash manpage):

  • initial word splitting
  • brace expansion
  • tilde expansion
  • parameter, variable and arithmetic expansion
  • command substitution
  • secondary word splitting
  • path expansion (aka globbing)
  • quote removal

Using $cmd directly gets it replaced by your command during the parameter expansion phase, and it then undergoes all following transformations.

Using eval "$cmd" does nothing until the quote removal phase, where $cmd is returned as is, and passed as a parameter to eval, whose function is to run the whole chain again before executing.

So basically, they're the same in most cases, and differ when your command makes use of the transformation steps up to parameter expansion. For example, using brace expansion:

$ cmd="echo foo{bar,baz}"
$ $cmd
foo{bar,baz}
$ eval "$cmd"
foobar foobaz

Ruby on Rails 3 Can't connect to local MySQL server through socket '/tmp/mysql.sock' on OSX

"/tmp/mysql.sock" will be created automatically when you start the MySQL server. So remember to do that before starting the rails server.

Convert Python dictionary to JSON array

If you are fine with non-printable symbols in your json, then add ensure_ascii=False to dumps call.

>>> json.dumps(your_data, ensure_ascii=False)

If ensure_ascii is false, then the return value will be a unicode instance subject to normal Python str to unicode coercion rules instead of being escaped to an ASCII str.

Does Android support near real time push notification?

As GTalk is gone from the SDK, it might be a good idea to make a 'standard' push messaging system. That way, only one service has to run, only one extra tcp connection needs to be open. Applications should talk to this service using Intents and should first request permission to send and receive notification from the service. The service should then notify the user a new application wants to send and receive messages. The user will then grant or deny permission, so he stays in control. The application will then register an action + category to the service, so the service knows how to deliver the pushed message.

Would the a good idea or not?

Flutter: RenderBox was not laid out

I had a simmilar problem, but in my case I was put a row in the leading of the Listview, and it was consumming all the space, of course. I just had to take the Row out of the leading, and it was solved. I would recomend to check if the problem is a widget larger than its containner can have.

How do I set GIT_SSL_NO_VERIFY for specific repos only?

This works for me:

git init
git config --global http.sslVerify false
git clone https://myurl/myrepo.git

Dynamic height for DIV

calculate the height of each link no do this

document.getElementById("products").style.height= height_of_each_link* no_of_link

Chrome blocks different origin requests

This is a security update. If an attacker can modify some file in the web server (the JS one, for example), he can make every loaded pages to download another script (for example to keylog your password or steal your SessionID and send it to his own server).

To avoid it, the browser check the Same-origin policy

Your problem is that the browser is trying to load something with your script (with an Ajax request) that is on another domain (or subdomain). To avoid it (if it is on your own website) you can:

TypeScript typed array usage

You could try either of these. They are not giving me errors.

It is also the suggested method from typescript for array declaration.

By using the Array<Thing> it is making use of the generics in typescript. It is similar to asking for a List<T> in c# code.

// Declare with default value
private _possessions: Array<Thing> = new Array<Thing>();
// or
private _possessions: Array<Thing> = [];
// or -> prefered by ts-lint
private _possessions: Thing[] = [];

or

// declare
private _possessions: Array<Thing>;
// or -> preferd by ts-lint
private _possessions: Thing[];

constructor(){
    //assign
    this._possessions = new Array<Thing>();
    //or
    this._possessions = [];
}

Run a Python script from another Python script, passing in arguments

This is inherently the wrong thing to do. If you are running a Python script from another Python script, you should communicate through Python instead of through the OS:

import script1

In an ideal world, you will be able to call a function inside script1 directly:

for i in range(whatever):
    script1.some_function(i)

If necessary, you can hack sys.argv. There's a neat way of doing this using a context manager to ensure that you don't make any permanent changes.

import contextlib
@contextlib.contextmanager
def redirect_argv(num):
    sys._argv = sys.argv[:]
    sys.argv=[str(num)]
    yield
    sys.argv = sys._argv

with redirect_argv(1):
    print(sys.argv)

I think this is preferable to passing all your data to the OS and back; that's just silly.

How do I run Python code from Sublime Text 2?

Cool U guys, I just found this:

http://ptomato.wordpress.com/2012/02/09/geek-tip-running-python-guis-in-sublime-text-2/

It explains (like one of the answers above) how to edit this exec.py in the default directory.

I had the problem that my PYTHON UI APPLICATION would not start. I commented out the last line from the following snipped:

    # Hide the console window on Windows
    startupinfo = None
    if os.name == "nt":
        startupinfo = subprocess.STARTUPINFO()
        #startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW

and, taaadaaaa, I could start my app by pressing Ctrl+B. Funny line anyways, uh? And a big thank you to whoever wrote that article ;-)

Getting checkbox values on submit

It's very simple.

The checkbox field is like an input text. If you don't write anything in the field, it will say the field doesn't exist.

<form method="post">
    <input type="checkbox" name="check">This is how it works!<br>
    <button type="submit" name="submit">Submit</button>
</form>
<?php
if(isset($_POST['submit'])) {
    if(!isset($_POST['check'])) {
        echo "Not selected!";
    }else{
        echo "Selected!";
    }
}
?>

Moment.js transform to date object

let dateVar = moment('any date value');
let newDateVar = dateVar.utc().format();

nice and clean!!!!

C read file line by line

//open and get the file handle
FILE* fh;
fopen_s(&fh, filename, "r");

//check if file exists
if (fh == NULL){
    printf("file does not exists %s", filename);
    return 0;
}


//read line by line
const size_t line_size = 300;
char* line = malloc(line_size);
while (fgets(line, line_size, fh) != NULL)  {
    printf(line);
}
free(line);    // dont forget to free heap memory

Why shouldn't I use "Hungarian Notation"?

I tend to use Hungarian Notation with ASP.NET server controls only, otherwise I find it too hard to work out what controls are what on the form.

Take this code snippet:

<asp:Label ID="lblFirstName" runat="server" Text="First Name" />
<asp:TextBox ID="txtFirstName" runat="server" />
<asp:RequiredFieldValidator ID="rfvFirstName" runat="server" ... />

If someone can show a better way of having that set of control names without Hungarian I'd be tempted to move to it.

How to count the number of columns in a table using SQL?

select count(*) 
from user_tab_columns
where table_name='MYTABLE' --use upper case

Instead of uppercase you can use lower function. Ex: select count(*) from user_tab_columns where lower(table_name)='table_name';

Filtering a list based on a list of booleans

With numpy:

In [128]: list_a = np.array([1, 2, 4, 6])
In [129]: filter = np.array([True, False, True, False])
In [130]: list_a[filter]

Out[130]: array([1, 4])

or see Alex Szatmary's answer if list_a can be a numpy array but not filter

Numpy usually gives you a big speed boost as well

In [133]: list_a = [1, 2, 4, 6]*10000
In [134]: fil = [True, False, True, False]*10000
In [135]: list_a_np = np.array(list_a)
In [136]: fil_np = np.array(fil)

In [139]: %timeit list(itertools.compress(list_a, fil))
1000 loops, best of 3: 625 us per loop

In [140]: %timeit list_a_np[fil_np]
10000 loops, best of 3: 173 us per loop

Can Android do peer-to-peer ad-hoc networking?

you can connect your android device to a known ad-hoc network.

edit /system/etc/wifi/tiwlan.ini

WiFiAdhoc = 1
dot11DesiredSSID = <your_network_ssid>
dot11DesiredBSSType = 0 

edit /data/misc/wifi/wpa_supplicant.conf

ctrl_interface=tiwlan0
update_config=1
eapol_version=1
ap_scan=2

if that is too simplistic, see these instructions.

Running Groovy script from the command line

It will work on Linux kernel 2.6.28 (confirmed on 4.9.x). It won't work on FreeBSD and other Unix flavors.

Your /usr/local/bin/groovy is a shell script wrapping the Java runtime running Groovy.

See the Interpreter Scripts section of EXECVE(2) and EXECVE(2).

Bash script to check running process

A simple script version of one of Andor's above suggestions:

!/bin/bash

pgrep $1 && echo Running

If the above script is called test.sh then, in order to test, type: test.sh NameOfProcessToCheck

e.g. test.sh php

How to convert a time string to seconds?

Inspired by sverrir-sigmundarson's comment:

def time_to_sec(time_str):
    return sum(x * int(t) for x, t in zip([1, 60, 3600], reversed(time_str.split(":"))))

How to use Fiddler to monitor WCF service

Standard WCF Tracing/Diagnostics

If for some reason you are unable to get Fiddler to work, or would rather log the requests another way, another option is to use the standard WCF tracing functionality. This will produce a file that has a nice viewer.

Docs

See https://docs.microsoft.com/en-us/dotnet/framework/wcf/samples/tracing-and-message-logging

Configuration

Add the following to your config, make sure c:\logs exists, rebuild, and make requests:

  <system.serviceModel>
    <diagnostics>
      <!-- Enable Message Logging here. -->
      <!-- log all messages received or sent at the transport or service model levels -->
      <messageLogging logEntireMessage="true"
                      maxMessagesToLog="300"
                      logMessagesAtServiceLevel="true"
                      logMalformedMessages="true"
                      logMessagesAtTransportLevel="true" />
    </diagnostics>
  </system.serviceModel>

  <system.diagnostics>
    <sources>
      <source name="System.ServiceModel" switchValue="Information,ActivityTracing"
        propagateActivity="true">
        <listeners>
          <add name="xml" />
        </listeners>
      </source>
      <source name="System.ServiceModel.MessageLogging">
        <listeners>
          <add name="xml" />
        </listeners>
      </source>
    </sources>
    <sharedListeners>
      <add initializeData="C:\logs\TracingAndLogging-client.svclog" type="System.Diagnostics.XmlWriterTraceListener"
        name="xml" />
    </sharedListeners>
    <trace autoflush="true" />
  </system.diagnostics>

Apache Server (xampp) doesn't run on Windows 10 (Port 80)

This fixed node.js not running on port 80 under Windows 10 as well, I was getting a listen eacces error. Start > Services, find "World Wide Web Publish Service" and disable it, exactly as paaacman described.

Transparent CSS background color

To achieve it, you have to modify the background-color of the element.

Ways to create a (semi-) transparent color:

  • The CSS color name transparent creates a completely transparent color.

    Usage:

      .transparent{
        background-color: transparent;
      }
    
  • Using rgba or hsla color functions, that allow you to add the alpha channel (opacity) to the rgb and hsl functions. Their alpha values range from 0 - 1.

    Usage:

      .semi-transparent-yellow{
        background-color: rgba(255, 255, 0, 0.5);
      }
      .transparent{
        background-color:  hsla(0, 0%, 0%, 0);
      }
    
  • Besides the already mentioned solutions, you can also use the HEX format with alpha value (#RRGGBBAA or #RGBA notation).

    That's pretty new (contained by CSS Color Module Level 4), but already implemented in larger browsers (sorry, no IE).

    This differs from the other solutions, as this treats the alpha channel (opacity) as a hexadecimal value as well, making it range from 0 - 255 (FF).

    Usage:

      .semi-transparent-yellow{
        background-color: #FFFF0080;
      }
      .transparent{
        background-color: #0000;
      }
    

You can try them out as well:

  • transparent:

_x000D_
_x000D_
div {
  position: absolute;
  top: 50px;
  left: 100px;
  height: 100px;
  width: 200px;
  text-align: center;
  line-height: 100px;
  border: 1px dashed grey;
  
  background-color: transparent;
}
_x000D_
<img src="https://via.placeholder.com/200x100">
<div>
  Using `transparent`
</div>
_x000D_
_x000D_
_x000D_

  • rgba():

_x000D_
_x000D_
div {
  position: absolute;
  top: 50px;
  left: 100px;
  height: 100px;
  width: 200px;
  text-align: center;
  line-height: 100px;
  border: 1px dashed grey;
  
  background-color: rgba(0, 255, 0, 0.3);
}
_x000D_
<img src="https://via.placeholder.com/200x100">
<div>
  Using `rgba()`
</div>
_x000D_
_x000D_
_x000D_

  • #RRGGBBAA:

_x000D_
_x000D_
div {
  position: absolute;
  top: 50px;
  left: 100px;
  height: 100px;
  width: 200px;
  text-align: center;
  line-height: 100px;
  border: 1px dashed grey;
  
  background-color: #FF000060
}
_x000D_
<img src="https://via.placeholder.com/200x100">
<div>
  Using `#RRGGBBAA`
</div>
_x000D_
_x000D_
_x000D_

Escape dot in a regex range

The dot operator . does not need to be escaped inside of a character class [].

How to access child's state in React?

Its 2020 and lots of you will come here looking for a similar solution but with Hooks ( They are great! ) and with latest approaches in terms of code cleanliness and syntax.

So as previous answers had stated, the best approach to this kind of problem is to hold the state outside of child component fieldEditor. You could do that in multiple ways.

The most "complex" is with global context (state) that both parent and children could access and modify. Its a great solution when components are very deep in the tree hierarchy and so its costly to send props in each level.

In this case I think its not worth it, and more simple approach will bring us the results we want, just using the powerful React.useState().

Approach with React.useState() hook, way simpler than with Class components

As said we will deal with changes and store the data of our child component fieldEditor in our parent fieldForm. To do that we will send a reference to the function that will deal and apply the changes to the fieldForm state, you could do that with:

function FieldForm({ fields }) {
  const [fieldsValues, setFieldsValues] = React.useState({});
  const handleChange = (event, fieldId) => {
    let newFields = { ...fieldsValues };
    newFields[fieldId] = event.target.value;

    setFieldsValues(newFields);
  };

  return (
    <div>
      {fields.map(field => (
        <FieldEditor
          key={field}
          id={field}
          handleChange={handleChange}
          value={fieldsValues[field]}
        />
      ))}
      <div>{JSON.stringify(fieldsValues)}</div>
    </div>
  );
}

Note that React.useState({}) will return an array with position 0 being the value specified on call (Empty object in this case), and position 1 being the reference to the function that modifies the value.

Now with the child component, FieldEditor, you don't even need to create a function with a return statement, a lean constant with an arrow function will do!

const FieldEditor = ({ id, value, handleChange }) => (
  <div className="field-editor">
    <input onChange={event => handleChange(event, id)} value={value} />
  </div>
);

Aaaaand we are done, nothing more, with just these two slime functional components we have our end goal "access" our child FieldEditor value and show it off in our parent.

You could check the accepted answer from 5 years ago and see how Hooks made React code leaner (By a lot!).

Hope my answer helps you learn and understand more about Hooks, and if you want to check a working example here it is.

Add JsonArray to JsonObject

Just try below a simple solution:

JsonObject body=new JsonObject();
body.add("orders", (JsonElement) orders);

whenever my JSON request is like:

{
      "role": "RT",
      "orders": [
        {
          "order_id": "ORDER201908aPq9Gs",
          "cart_id": 164444,
          "affiliate_id": 0,
          "orm_order_status": 9,
          "status_comments": "IC DUE - Auto moved to Instruction Call Due after 48hrs",
          "status_date": "2020-04-15",
        }
      ]
    }

Generate a random letter in Python

def create_key(key_len):
    key = ''
    valid_characters_list = string.letters + string.digits
    for i in range(key_len):
        character = choice(valid_characters_list)
        key = key + character
    return key

def create_key_list(key_num):
    keys = []
    for i in range(key_num):
        key = create_key(key_len)
        if key not in keys:
            keys.append(key)
    return keys

java.lang.ClassNotFoundException: javax.servlet.jsp.jstl.core.Config

Just a quick comment: sometimes Maven does not copy the jstl-.jar to the WEB-INF folder even if the pom.xml has the entry for it.

I had to manually copy the JSTL jar to /WEB-INF/lib on the file system. That resolved the problem. The issue may be related to Maven war packaging plugin.

Change x axes scale in matplotlib

This is not so much an answer to your original question as to one of the queries you had in the body of your question.

A little preamble, so that my naming doesn't seem strange:

import matplotlib
from matplotlib import rc
from matplotlib.figure import Figure
ax = self.figure.add_subplot( 111 )

As has been mentioned you can use ticklabel_format to specify that matplotlib should use scientific notation for large or small values:

ax.ticklabel_format(style='sci',scilimits=(-3,4),axis='both')

You can affect the way that this is displayed using the flags in rcParams (from matplotlib import rcParams) or by setting them directly. I haven't found a more elegant way of changing between '1e' and 'x10^' scientific notation than:

ax.xaxis.major.formatter._useMathText = True

This should give you the more Matlab-esc, and indeed arguably better appearance. I think the following should do the same:

rc('text', usetex=True)

Genymotion Android emulator - adb access?

Just Go To the Genymotion Installation Directory and then in folder tools you will see adb.exe there open command prompt here and run adb commands

How to comment out a block of code in Python

The only way you can do this without triple quotes is to add an:

if False:

And then indent all your code. Note that the code will still need to have proper syntax.


Many Python IDEs can add # for you on each selected line, and remove them when un-commenting too. Likewise, if you use vi or Emacs you can create a macro to do this for you for a block of code.

Java time-based map/cache with expiring keys

Yes. Google Collections, or Guava as it is named now has something called MapMaker which can do exactly that.

ConcurrentMap<Key, Graph> graphs = new MapMaker()
   .concurrencyLevel(4)
   .softKeys()
   .weakValues()
   .maximumSize(10000)
   .expiration(10, TimeUnit.MINUTES)
   .makeComputingMap(
       new Function<Key, Graph>() {
         public Graph apply(Key key) {
           return createExpensiveGraph(key);
         }
       });

Update:

As of guava 10.0 (released September 28, 2011) many of these MapMaker methods have been deprecated in favour of the new CacheBuilder:

LoadingCache<Key, Graph> graphs = CacheBuilder.newBuilder()
    .maximumSize(10000)
    .expireAfterWrite(10, TimeUnit.MINUTES)
    .build(
        new CacheLoader<Key, Graph>() {
          public Graph load(Key key) throws AnyException {
            return createExpensiveGraph(key);
          }
        });

Add a scrollbar to a <textarea>

textarea {
    overflow-y: scroll; /* Vertical scrollbar */
    overflow: scroll; /* Horizontal and vertical scrollbar*/
}

Understanding events and event handlers in C#

To understand event handlers, you need to understand delegates. In C#, you can think of a delegate as a pointer (or a reference) to a method. This is useful because the pointer can be passed around as a value.

The central concept of a delegate is its signature, or shape. That is (1) the return type and (2) the input arguments. For example, if we create a delegate void MyDelegate(object sender, EventArgs e), it can only point to methods which return void, and take an object and EventArgs. Kind of like a square hole and a square peg. So we say these methods have the same signature, or shape, as the delegate.

So knowing how to create a reference to a method, let's think about the purpose of events: we want to cause some code to be executed when something happens elsewhere in the system - or "handle the event". To do this, we create specific methods for the code we want to be executed. The glue between the event and the methods to be executed are the delegates. The event must internally store a "list" of pointers to the methods to call when the event is raised.* Of course, to be able to call a method, we need to know what arguments to pass to it! We use the delegate as the "contract" between the event and all the specific methods that will be called.

So the default EventHandler (and many like it) represents a specific shape of method (again, void/object-EventArgs). When you declare an event, you are saying which shape of method (EventHandler) that event will invoke, by specifying a delegate:

//This delegate can be used to point to methods
//which return void and take a string.
public delegate void MyEventHandler(string foo);

//This event can cause any method which conforms
//to MyEventHandler to be called.
public event MyEventHandler SomethingHappened;

//Here is some code I want to be executed
//when SomethingHappened fires.
void HandleSomethingHappened(string foo)
{
    //Do some stuff
}

//I am creating a delegate (pointer) to HandleSomethingHappened
//and adding it to SomethingHappened's list of "Event Handlers".
myObj.SomethingHappened += new MyEventHandler(HandleSomethingHappened);

//To raise the event within a method.
SomethingHappened("bar");

(*This is the key to events in .NET and peels away the "magic" - an event is really, under the covers, just a list of methods of the same "shape". The list is stored where the event lives. When the event is "raised", it's really just "go through this list of methods and call each one, using these values as the parameters". Assigning an event handler is just a prettier, easier way of adding your method to this list of methods to be called).

creating json object with variables

It's called on Object Literal

I'm not sure what you want your structure to be, but according to what you have above, where you put the values in variables try this.

var formObject =  {"formObject": [
                {"firstName": firstName, "lastName": lastName},
                {"phoneNumber": phone},
                {"address": address},
                ]}

Although this seems to make more sense (Why do you have an array in the above literal?):

var formObject = {
   firstName: firstName
   ...
}

Data access object (DAO) in Java

Pojo also consider as Model class in Java where we can create getter and setter for particular variable defined in private . Remember all variables are here declared with private modifier

PHP - remove all non-numeric characters from a string

Use \D to match non-digit characters.

preg_replace('~\D~', '', $str);

Java Set retain order?

From the javadoc for Set.iterator():

Returns an iterator over the elements in this set. The elements are returned in no particular order (unless this set is an instance of some class that provides a guarantee).

And, as already stated by shuuchan, a TreeSet is an implemention of Set that has a guaranteed order:

The elements are ordered using their natural ordering, or by a Comparator provided at set creation time, depending on which constructor is used.

How to create own dynamic type or dynamic object in C#?

dynamic myDynamic = new { PropertyOne = true, PropertyTwo = false};

Counting in a FOR loop using Windows Batch script

Here is a batch file that generates all 10.x.x.x addresses

@echo off

SET /A X=0
SET /A Y=0
SET /A Z=0

:loop
SET /A X+=1
echo 10.%X%.%Y%.%Z%
IF "%X%" == "256" (
 GOTO end
 ) ELSE (
 GOTO loop2
 GOTO loop
 )


:loop2
SET /A Y+=1
echo 10.%X%.%Y%.%Z%
IF "%Y%" == "256" (
  SET /A Y=0
  GOTO loop
  ) ELSE (
   GOTO loop3
   GOTO loop2
 )


:loop3

SET /A Z+=1
echo 10.%X%.%Y%.%Z%
IF "%Z%" == "255" (
  SET /A Z=0
  GOTO loop2
 ) ELSE (
   GOTO loop3
 )

:end

MacOSX homebrew mysql root password

I stumbled across this too and the solution was unironically to simply run this:

mysql