Programs & Examples On #Qpixmap

The QPixmap class, part of the Qt framework, is an off-screen image representation that can be used as a paint device.

Qt: resizing a QLabel containing a QPixmap while keeping its aspect ratio

In order to change the label size you can select an appropriate size policy for the label like expanding or minimum expanding.

You can scale the pixmap by keeping its aspect ratio every time it changes:

QPixmap p; // load pixmap
// get label dimensions
int w = label->width();
int h = label->height();

// set a scaled pixmap to a w x h window keeping its aspect ratio 
label->setPixmap(p.scaled(w,h,Qt::KeepAspectRatio));

There are two places where you should add this code:

  • When the pixmap is updated
  • In the resizeEvent of the widget that contains the label

Angular and Typescript: Can't find names - Error: cannot find name

I am new to Angular but for me the solution was found by simply importing Input. Can't take credit for this one, found it on another board. This is a simple fix if you're having the same problem but if your issues are more complex I'd read the stuff above.

Mukesh:

you have to import input like this at top of child component

import { Directive, Component, OnInit, Input } from '@angular/core';

Convert JSON String To C# Object

Using dynamic object with JavaScriptSerializer.

JavaScriptSerializer serializer = new JavaScriptSerializer(); 
dynamic item = serializer.Deserialize<object>("{ \"test\":\"some data\" }");
string test= item["test"];

//test Result = "some data"

How to display a list inline using Twitter's Bootstrap

This solution works using Bootstrap v2, however in TBS3 the class INLINE. I haven't figured out what is the equivalent class (if there is one) in TBS3.

This gentleman had a pretty good article of the differences between v2 and v3.

http://mattduchek.com/differences-between-bootstrap-v2-3-and-v3-0/

EDIT - use CSS to target the li elements to solve your problem as below

    { display: inline-block; }

In my situation I was targeting the UL, instead of the LI

    nav ul li { display: inline-block; }

Replacing NULL and empty string within Select statement

Sounds like you want a view instead of altering actual table data.

Coalesce(NullIf(rtrim(Address.Country),''),'United States')

This will force your column to be null if it is actually an empty string (or blank string) and then the coalesce will have a null to work with.

FlutterError: Unable to load asset

I have the same issue. I've just run "$ flutter clean", then everything is OK.

More about this error

What is an .axd file?

An AXD file is a file used by ASP.NET applications for handling embedded resource requests. It contains instructions for retrieving embedded resources, such as images, JavaScript (.JS) files, and.CSS files. AXD files are used for injecting resources into the client-side webpage and access them on the server in a standard way.

Get year, month or day from numpy datetime64

As datetime is not stable in numpy I would use pandas for this:

In [52]: import pandas as pd

In [53]: dates = pd.DatetimeIndex(['2010-10-17', '2011-05-13', "2012-01-15"])

In [54]: dates.year
Out[54]: array([2010, 2011, 2012], dtype=int32)

Pandas uses numpy datetime internally, but seems to avoid the shortages, that numpy has up to now.

PHP shell_exec() vs exec()

shell_exec - Execute command via shell and return the complete output as a string

exec - Execute an external program.

The difference is that with shell_exec you get output as a return value.

Colouring plot by factor in R

The lattice library is another good option. Here I've added a legend on the right side and jittered the points because some of them overlapped.

xyplot(Sepal.Width ~ Sepal.Length, group=Species, data=iris, 
       auto.key=list(space="right"), 
       jitter.x=TRUE, jitter.y=TRUE)

example plot

Hot to get all form elements values using jQuery?

Try this for getting form input text value to JavaScript object...

var fieldPair = {};
$("#form :input").each(function() {
    if($(this).attr("name").length > 0) {
        fieldPair[$(this).attr("name")] = $(this).val();
    }
});

console.log(fieldPair);

DBMS_OUTPUT.PUT_LINE not printing

Set Query as below at first line

SET SERVEROUTPUT ON 

How to prevent buttons from submitting forms

Suppose your HTML form has id="form_id"

<form id="form_id">
<!--your HTML code-->
</form>

Add this jQuery snippet to your code to see result,

$("#form_id").submit(function(){
  return false;
});

How to check for an empty object in an AngularJS view

You have to just check that the object is null or not. AngularJs provide inbuilt directive ng-if. An example is given below.

<tr ng-repeat="key in object" ng-if="object != 'null'" >
    <td>{{object.key}}</td>
    <td>{{object.key}}</td>
</tr>

Mysql select distinct

You can use group by instead of distinct. Because when you use distinct, you'll get struggle to select all values from table. Unlike when you use group by, you can get distinct values and also all fields in table.

convert array into DataFrame in Python

In general you can use pandas rename function here. Given your dataframe you could change to a new name like this. If you had more columns you could also rename those in the dictionary. The 0 is the current name of your column

import pandas as pd    
import numpy as np   
e = np.random.normal(size=100)  
e_dataframe = pd.DataFrame(e)      

e_dataframe.rename(index=str, columns={0:'new_column_name'})

Using Chrome's Element Inspector in Print Preview Mode?

As of Chrome 48 (and perhaps a few versions earlier), the function seems to have moved yet again:

The first few steps are unchanged:

  1. Press F12 to bring up the developer tools

  2. Press ESC to open the console

According to the previous answers, the setting could then be found under the "Emulation" tab. As shown in the images below, it has now been moved to the "Rendering" tab, which can be brought up by clicking on the three dots to the left of the "Console" tab.

Tab selection

Setting selection

Best way to replace multiple characters in a string?

advanced way using regex

import re
text = "hello ,world!"
replaces = {"hello": "hi", "world":" 2020", "!":"."}
regex = re.sub("|".join(replaces.keys()), lambda match: replaces[match.string[match.start():match.end()]], text)
print(regex)

How to backup MySQL database in PHP?

Here is a pure PHP class to perform backups on MySQL databases not using mysqldump or mysql commands: Backing up MySQL databases with pure PHP

How do I plot list of tuples in Python?

As others have answered, scatter() or plot() will generate the plot you want. I suggest two refinements to answers that are already here:

  1. Use numpy to create the x-coordinate list and y-coordinate list. Working with large data sets is faster in numpy than using the iteration in Python suggested in other answers.

  2. Use pyplot to apply the logarithmic scale rather than operating directly on the data, unless you actually want to have the logs.

    import matplotlib.pyplot as plt
    import numpy as np
    
    data = [(2, 10), (3, 100), (4, 1000), (5, 100000)]
    data_in_array = np.array(data)
    '''
    That looks like array([[     2,     10],
                           [     3,    100],
                           [     4,   1000],
                           [     5, 100000]])
    '''
    
    transposed = data_in_array.T
    '''
    That looks like array([[     2,      3,      4,      5],
                           [    10,    100,   1000, 100000]])
    '''    
    
    x, y = transposed 
    
    # Here is the OO method
    # You could also the state-based methods of pyplot
    fig, ax = plt.subplots(1,1) # gets a handle for the AxesSubplot object
    ax.plot(x, y, 'ro')
    ax.plot(x, y, 'b-')
    ax.set_yscale('log')
    fig.show()
    

result

I've also used ax.set_xlim(1, 6) and ax.set_ylim(.1, 1e6) to make it pretty.

I've used the object-oriented interface to matplotlib. Because it offers greater flexibility and explicit clarity by using names of the objects created, the OO interface is preferred over the interactive state-based interface.

java.lang.IllegalStateException: Fragment not attached to Activity

This issue occurs whenever you call a context which is unavailable or null when you call it. This can be a situation when you are calling main activity thread's context on a background thread or background thread's context on main activity thread.

For instance , I updated my shared preference string like following.

editor.putString("penname",penNameEditeText.getText().toString());
editor.commit();
finish();

And called finish() right after it. Now what it does is that as commit runs on main thread and stops any other Async commits if coming until it finishes. So its context is alive until the write is completed. Hence previous context is live , causing the error to occur.

So make sure to have your code rechecked if there is some code having this context issue.

Call Jquery function

To call the function on click of some html element (control).

$('#controlID').click(myFunction);

You will need to ensure you bind the event when your html element is ready on which you binding the event. You can put the code in document.ready

$(document).ready(function(){
    $('#controlID').click(myFunction);
});

You can use anonymous function to bind the event to the html element.

$(document).ready(function(){
    $('#controlID').click(function(){
         $.messager.show({  
            title:'My Title',  
            msg:'The message content',  
            showType:'fade',  
            style:{  
                right:'',  
                bottom:''  
            }  
        });  
    });
});

If you want to bind click with many elements you can use class selector

$('.someclass').click(myFunction);

Edit based on comments by OP, If you want to call function under some condition

You can use if for conditional execution, for example,

if(a == 3)
     myFunction();

How to check if a string is numeric?

Here's how to check if the input contains a digit:

if (input.matches(".*\\d.*")) {
    // there's a digit somewhere in the input string 
}

How to extract base URL from a string in JavaScript?

I use a simple regex that extracts the host form the url:

function get_host(url){
    return url.replace(/^((\w+:)?\/\/[^\/]+\/?).*$/,'$1');
}

and use it like this

var url = 'http://www.sitename.com/article/2009/09/14/this-is-an-article/'
var host = get_host(url);

Note, if the url does not end with a / the host will not end in a /.

Here are some tests:

describe('get_host', function(){
    it('should return the host', function(){
        var url = 'http://www.sitename.com/article/2009/09/14/this-is-an-article/';
        assert.equal(get_host(url),'http://www.sitename.com/');
    });
    it('should not have a / if the url has no /', function(){
        var url = 'http://www.sitename.com';
        assert.equal(get_host(url),'http://www.sitename.com');
    });
    it('should deal with https', function(){
        var url = 'https://www.sitename.com/article/2009/09/14/this-is-an-article/';
        assert.equal(get_host(url),'https://www.sitename.com/');
    });
    it('should deal with no protocol urls', function(){
        var url = '//www.sitename.com/article/2009/09/14/this-is-an-article/';
        assert.equal(get_host(url),'//www.sitename.com/');
    });
    it('should deal with ports', function(){
        var url = 'http://www.sitename.com:8080/article/2009/09/14/this-is-an-article/';
        assert.equal(get_host(url),'http://www.sitename.com:8080/');
    });
    it('should deal with localhost', function(){
        var url = 'http://localhost/article/2009/09/14/this-is-an-article/';
        assert.equal(get_host(url),'http://localhost/');
    });
    it('should deal with numeric ip', function(){
        var url = 'http://192.168.18.1/article/2009/09/14/this-is-an-article/';
        assert.equal(get_host(url),'http://192.168.18.1/');
    });
});

Configuring so that pip install can work from github

You need the whole python package, with a setup.py file in it.

A package named foo would be:

foo # the installable package
+-- foo
¦   +-- __init__.py
¦   +-- bar.py
+-- setup.py

And install from github like:

$ pip install git+ssh://[email protected]/myuser/foo.git
or
$ pip install git+https://github.com/myuser/foo.git@v123
or
$ pip install git+https://github.com/myuser/foo.git@newbranch

More info at https://pip.pypa.io/en/stable/reference/pip_install/#vcs-support

"element.dispatchEvent is not a function" js error caught in firebug of FF3.0

You have to add

<script>jQuery.noConflict();</script>

after

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>

How to read a text file into a list or an array with Python

You can also use numpy loadtxt like

from numpy import loadtxt
lines = loadtxt("filename.dat", comments="#", delimiter=",", unpack=False)

Get the difference between two dates both In Months and days in sql

SELECT   (MONTHS_BETWEEN(date2,date1) +  (datediff(day,date2,date1))/30) as num_months,
datediff(day,date2,date1) as diff_in_days  FROM  dual;

// You should replace date2 with TO_DATE('2012/03/25', 'YYYY/MM/DD')
// You should replace date1 with TO_DATE('2012/01/01', 'YYYY/MM/DD')
// To get you results

How can I add additional PHP versions to MAMP

If you need to be able to switch between more than two versions at a time, you can use the following to change the version of PHP manually.

MAMP automatically rewrites the following line in your /Applications/MAMP/conf/apache/httpd.conf file when it restarts based on the settings in preferences. You can comment out this line and add the second one to the end of your file:

# Comment this out just under all the modules loaded
# LoadModule php5_module        /Applications/MAMP/bin/php/php5.x.x/modules/libphp5.so

At the bottom of the httpd.conf file, you'll see where additional configurations are loaded from the extra folder. Add this to the bottom of the httpd.conf file

# PHP Version Change
Include /Applications/MAMP/conf/apache/extra/httpd-php.conf

Then create a new file here: /Applications/MAMP/conf/apache/extra/httpd-php.conf

# Uncomment the version of PHP you want to run with MAMP
# LoadModule php5_module /Applications/MAMP/bin/php/php5.2.17/modules/libphp5.so
# LoadModule php5_module /Applications/MAMP/bin/php/php5.3.27/modules/libphp5.so
# LoadModule php5_module /Applications/MAMP/bin/php/php5.4.19/modules/libphp5.so
LoadModule php5_module /Applications/MAMP/bin/php/php5.5.3/modules/libphp5.so

After you have this setup, just uncomment the version of PHP you want to use and restart the servers!

Pass parameters in setInterval function

I know this topic is so old but here is my solution about passing parameters in setInterval function.

Html:

var fiveMinutes = 60 * 2;
var display = document.querySelector('#timer');
startTimer(fiveMinutes, display);

JavaScript:

function startTimer(duration, display) {
    var timer = duration,
        minutes, seconds;

    setInterval(function () {
        minutes = parseInt(timer / 60, 10);
        seconds = parseInt(timer % 60, 10);

        minutes = minutes < 10 ? "0" + minutes : minutes;
        seconds = seconds < 10 ? "0" + seconds : seconds;

        display.textContent = minutes + ":" + seconds;
        --timer; // put boolean value for minus values.

    }, 1000);
}

Round to 5 (or other number) in Python

I don't know of a standard function in Python, but this works for me:

Python 2

def myround(x, base=5):
    return int(base * round(float(x)/base))

Python3

def myround(x, base=5):
    return base * round(x/base)

It is easy to see why the above works. You want to make sure that your number divided by 5 is an integer, correctly rounded. So, we first do exactly that (round(float(x)/5) where float is only needed in Python2), and then since we divided by 5, we multiply by 5 as well. The final conversion to int is because round() returns a floating-point value in Python 2.

I made the function more generic by giving it a base parameter, defaulting to 5.

How to get pixel data from a UIImage (Cocoa Touch) or CGImage (Core Graphics)?

To access the raw RGB values of an UIImage in Swift 5 use the underlying CGImage and its dataProvider:

import UIKit

let image = UIImage(named: "example.png")!

guard let cgImage = image.cgImage,
    let data = cgImage.dataProvider?.data,
    let bytes = CFDataGetBytePtr(data) else {
    fatalError("Couldn't access image data")
}
assert(cgImage.colorSpace?.model == .rgb)

let bytesPerPixel = cgImage.bitsPerPixel / cgImage.bitsPerComponent
for y in 0 ..< cgImage.height {
    for x in 0 ..< cgImage.width {
        let offset = (y * cgImage.bytesPerRow) + (x * bytesPerPixel)
        let components = (r: bytes[offset], g: bytes[offset + 1], b: bytes[offset + 2])
        print("[x:\(x), y:\(y)] \(components)")
    }
    print("---")
}

https://www.ralfebert.de/ios/examples/image-processing/uiimage-raw-pixels/

How to check if String value is Boolean type in Java?

Actually, checking for a Boolean type in a String (which is a type) is impossible. Basically you're asking how to do a 'string compare'.

Like others stated. You need to define when you want to return "true" or "false" (under what conditions). Do you want it to be case(in)sensitive? What if the value is null?

I think Boolean.valueOf() is your friend, javadoc says:

Returns a Boolean with a value represented by the specified String. The Boolean returned represents the value true if the string argument is not null and is equal, ignoring case, to the string "true".

Example: Boolean.valueOf("True") returns true.
Example: Boolean.valueOf("yes") returns false.

Why does the C++ STL not provide any "tree" containers?

All STL containers can be used with iterators. You can't have an iterator an a tree, because you don't have ''one right'' way do go through the tree.

load scripts asynchronously

You can use LABJS or RequreJS

Script loaders like LABJS, RequireJS will improve the speed and quality of your code.

How to reset settings in Visual Studio Code?

The best easiest way I found to reset settings:

Open Settings page (Ctrl+Shift+P):

enter image description here

Go onto your desire setting section to reset, click on icon and then Reset Setting :

enter image description here

Running PowerShell as another user, and launching a script

In windows server 2012 or 2016 you can search for Windows PowerShell and then "Pin to Start". After this you will see "Run as different user" option on a right click on the start page tiles.

Extracting substrings in Go

WARNING: operating on strings alone will only work with ASCII and will count wrong when input is a non-ASCII UTF-8 encoded character, and will probably even corrupt characters since it cuts multibyte chars mid-sequence.

Here's a UTF-8-aware version:

// NOTE: this isn't multi-Unicode-codepoint aware, like specifying skintone or
//       gender of an emoji: https://unicode.org/emoji/charts/full-emoji-modifiers.html
func substr(input string, start int, length int) string {
    asRunes := []rune(input)
    
    if start >= len(asRunes) {
        return ""
    }
    
    if start+length > len(asRunes) {
        length = len(asRunes) - start
    }
    
    return string(asRunes[start : start+length])
}

Is there a Java equivalent or methodology for the typedef keyword in C++?

If this is what you mean, you can simply extend the class you would like to typedef, e.g.:

public class MyMap extends HashMap<String, String> {}

How to sort a data frame by alphabetic order of a character variable in R?

The order() function fails when the column has levels or factor. It works properly when stringsAsFactors=FALSE is used in data.frame creation.

Adding a public key to ~/.ssh/authorized_keys does not log me in automatically

Beware that SELinux can trigger this error as well, even if all permissions seem to be OK. Disabling it did the trick for me (insert usual disclaimers about disabling it).

How to select true/false based on column value?

At least in Postgres you can use the following statement:

SELECT EntityID, EntityName, EntityProfile IS NOT NULL AS HasProfile FROM Entity

List file names based on a filename pattern and file content?

Assume LMN2011* files are inside /home/me but skipping anything in /home/me/temp or below:

find /home/me -name 'LMN2011*' -not -path "/home/me/temp/*" -print | xargs grep 'LMN20113456'

Class 'DOMDocument' not found

For Centos 7 and php 7.1:
yum install php71w-xml
apachectl restart

Check if a file is executable

First you need to remember that in Unix and Linux, everything is a file, even directories. For a file to have the rights to be executed as a command, it needs to satisfy 3 conditions:

  1. It needs to be a regular file
  2. It needs to have read-permissions
  3. It needs to have execute-permissions

So this can be done simply with:

[ -f "${file}" ] && [ -r "${file}" ] && [ -x "${file}" ]

If your file is a symbolic link to a regular file, the test command will operate on the target and not the link-name. So the above command distinguishes if a file can be used as a command or not. So there is no need to pass the file first to realpath or readlink or any of those variants.

If the file can be executed on the current OS, that is a different question. Some answers above already pointed to some possibilities for that, so there is no need to repeat it here.

Group query results by month and year in postgresql

select to_char(date,'Mon') as mon,
       extract(year from date) as yyyy,
       sum("Sales") as "Sales"
from yourtable
group by 1,2

At the request of Radu, I will explain that query:

to_char(date,'Mon') as mon, : converts the "date" attribute into the defined format of the short form of month.

extract(year from date) as yyyy : Postgresql's "extract" function is used to extract the YYYY year from the "date" attribute.

sum("Sales") as "Sales" : The SUM() function adds up all the "Sales" values, and supplies a case-sensitive alias, with the case sensitivity maintained by using double-quotes.

group by 1,2 : The GROUP BY function must contain all columns from the SELECT list that are not part of the aggregate (aka, all columns not inside SUM/AVG/MIN/MAX etc functions). This tells the query that the SUM() should be applied for each unique combination of columns, which in this case are the month and year columns. The "1,2" part is a shorthand instead of using the column aliases, though it is probably best to use the full "to_char(...)" and "extract(...)" expressions for readability.

Java POI : How to read Excel cell value and not the formula computing it?

There is an alternative command where you can get the raw value of a cell where formula is put on. It's returns type is String. Use:

cell.getRawValue();

Vue JS mounted()

You can also move mounted out of the Vue instance and make it a function in the top-level scope. This is also a useful trick for server side rendering in Vue.

function init() {
  // Use `this` normally
}

new Vue({
  methods:{
    init
  },
  mounted(){
    init.call(this)
  }
})

Cannot install node modules that require compilation on Windows 7 x64/VS2012

Thanks to @felixrieseberg, you just need to install windows-build-tools npm package and you are good to go.

npm install --global --production windows-build-tools

You won't need to install Visual Studio.

You won't need to install Microsoft Build Tools.

From the repo:

After installation, npm will automatically execute this module, which downloads and installs Visual C++ Build Tools 2015, provided free of charge by Microsoft. These tools are required to compile popular native modules. It will also install Python 2.7, configuring your machine and npm appropriately.

Windows Vista / 7 requires .NET Framework 4.5.1 (Currently not installed automatically by this package)

Both installations are conflict-free, meaning that they do not mess with existing installations of Visual Studio, C++ Build Tools, or Python.

Django URL Redirect

In Django 1.8, this is how I did mine.

from django.views.generic.base import RedirectView

url(r'^$', views.comingSoon, name='homepage'),
# whatever urls you might have in here
# make sure the 'catch-all' url is placed last
url(r'^.*$', RedirectView.as_view(pattern_name='homepage', permanent=False))

Instead of using url, you can use the pattern_name, which is a bit un-DRY, and will ensure you change your url, you don't have to change the redirect too.

How to use TLS 1.2 in Java 6

You must create your own SSLSocketFactory based on Bouncy Castle. After to use it, pass to the common HttpsConnextion for using this customized SocketFactory.

1. First : Create a TLSConnectionFactory

Here one tips:

1.1 Extend SSLConnectionFactory

1.2 Override this method :

@Override 
public Socket createSocket(Socket socket, final String host, int port, boolean arg3)

This method will call the next internal method,

1.3 Implement an internal method _createSSLSocket(host, tlsClientProtocol);

Here you must create a Socket using TlsClientProtocol . The trick is override ...startHandshake() method calling TlsClientProtocol

 private SSLSocket _createSSLSocket(final String host , final TlsClientProtocol tlsClientProtocol) {
     return new SSLSocket() {    
       .... Override and implement SSLSocket methods,  particulary: 
            startHandshake() {
             }    
     }

     

Important : The full sample how to use TLS Client Protocol is well explained here: Using BouncyCastle for a simple HTTPS query

2. Second : Use this Customized SSLConnextionFactory on common HTTPSConnection.

This is important ! In other samples you can see into the web , u see hard-coded HTTP Commands....so with a customized SSLConnectionFactory u don't need nothing more...

  URL myurl = new URL( "http:// ...URL tha only Works in TLS 1.2);
  HttpsURLConnection  con = (HttpsURLConnection )myurl.openConnection();
  con.setSSLSocketFactory(new TSLSocketConnectionFactory());

Flatten List in LINQ

With query syntax:

var values =
from inner in outer
from value in inner
select value;

How to permanently export a variable in Linux?

A particular example: I have Java 7 and Java 6 installed, I need to run some builds with 6, others with 7. Therefore I need to dynamically alter JAVA_HOME so that maven picks up what I want for each build. I did the following:

  • created j6.sh script which simply does export JAVA_HOME=... path to j6 install...
  • then, as suggested by one of the comments above, whenever I need J6 for a build, I run source j6.sh in that respective command terminal. By default, my JAVA_HOME is set to J7.

Hope this helps.

Java - Convert int to Byte Array of 4 Bytes?

public static  byte[] my_int_to_bb_le(int myInteger){
    return ByteBuffer.allocate(4).order(ByteOrder.LITTLE_ENDIAN).putInt(myInteger).array();
}

public static int my_bb_to_int_le(byte [] byteBarray){
    return ByteBuffer.wrap(byteBarray).order(ByteOrder.LITTLE_ENDIAN).getInt();
}

public static  byte[] my_int_to_bb_be(int myInteger){
    return ByteBuffer.allocate(4).order(ByteOrder.BIG_ENDIAN).putInt(myInteger).array();
}

public static int my_bb_to_int_be(byte [] byteBarray){
    return ByteBuffer.wrap(byteBarray).order(ByteOrder.BIG_ENDIAN).getInt();
}

How can I get client information such as OS and browser

Your best bet is User-Agent header. You can get it like this in JSP or Servlet,

String userAgent = request.getHeader("User-Agent");

The header looks like this,

User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9.0.13) Gecko/2009073021 Firefox/3.0.13

It provides detailed information on browser. However, it's pretty much free format so it's very hard to decipher every single one. You just need to figure out which browsers you will support and write parser for each one. When you try to identify the version of browser, always check newer version first. For example, IE6 user-agent may contain IE5 for backward compatibility. If you check IE5 first, IE6 will be categorized as IE5 also.

You can get a full list of all user-agent values from this web site,

http://www.user-agents.org/

With User-Agent, you can tell the exact version of the browser. You can get a pretty good idea on OS but you may not be able to distinguish between different versions of the same OS, for example, Windows NT and 2000 may use same User-Agent.

There is nothing about resolution. However, you can get this with Javascript on an AJAX call.

Tkinter scrollbar for frame

Please note that the proposed code is only valid with Python 2

Here is an example:

from Tkinter import *   # from x import * is bad practice
from ttk import *

# http://tkinter.unpythonic.net/wiki/VerticalScrolledFrame

class VerticalScrolledFrame(Frame):
    """A pure Tkinter scrollable frame that actually works!
    * Use the 'interior' attribute to place widgets inside the scrollable frame
    * Construct and pack/place/grid normally
    * This frame only allows vertical scrolling

    """
    def __init__(self, parent, *args, **kw):
        Frame.__init__(self, parent, *args, **kw)            

        # create a canvas object and a vertical scrollbar for scrolling it
        vscrollbar = Scrollbar(self, orient=VERTICAL)
        vscrollbar.pack(fill=Y, side=RIGHT, expand=FALSE)
        canvas = Canvas(self, bd=0, highlightthickness=0,
                        yscrollcommand=vscrollbar.set)
        canvas.pack(side=LEFT, fill=BOTH, expand=TRUE)
        vscrollbar.config(command=canvas.yview)

        # reset the view
        canvas.xview_moveto(0)
        canvas.yview_moveto(0)

        # create a frame inside the canvas which will be scrolled with it
        self.interior = interior = Frame(canvas)
        interior_id = canvas.create_window(0, 0, window=interior,
                                           anchor=NW)

        # track changes to the canvas and frame width and sync them,
        # also updating the scrollbar
        def _configure_interior(event):
            # update the scrollbars to match the size of the inner frame
            size = (interior.winfo_reqwidth(), interior.winfo_reqheight())
            canvas.config(scrollregion="0 0 %s %s" % size)
            if interior.winfo_reqwidth() != canvas.winfo_width():
                # update the canvas's width to fit the inner frame
                canvas.config(width=interior.winfo_reqwidth())
        interior.bind('<Configure>', _configure_interior)

        def _configure_canvas(event):
            if interior.winfo_reqwidth() != canvas.winfo_width():
                # update the inner frame's width to fill the canvas
                canvas.itemconfigure(interior_id, width=canvas.winfo_width())
        canvas.bind('<Configure>', _configure_canvas)


if __name__ == "__main__":

    class SampleApp(Tk):
        def __init__(self, *args, **kwargs):
            root = Tk.__init__(self, *args, **kwargs)


            self.frame = VerticalScrolledFrame(root)
            self.frame.pack()
            self.label = Label(text="Shrink the window to activate the scrollbar.")
            self.label.pack()
            buttons = []
            for i in range(10):
                buttons.append(Button(self.frame.interior, text="Button " + str(i)))
                buttons[-1].pack()

    app = SampleApp()
    app.mainloop()

It does not yet have the mouse wheel bound to the scrollbar but it is possible. Scrolling with the wheel can get a bit bumpy, though.

edit:

to 1)
IMHO scrolling frames is somewhat tricky in Tkinter and does not seem to be done a lot. It seems there is no elegant way to do it.
One problem with your code is that you have to set the canvas size manually - that's what the example code I posted solves.

to 2)
You are talking about the data function? Place works for me, too. (In general I prefer grid).

to 3)
Well, it positions the window on the canvas.

One thing I noticed is that your example handles mouse wheel scrolling by default while the one I posted does not. Will have to look at that some time.

Powershell 2 copy-item which creates a folder if doesn't exist

Yes, add the -Force parameter.

copy-item $from $to -Recurse -Force

Disable time in bootstrap date time picker

Not as put off time and language at a time I put this and not work

$(function () {
    $('#datetimepicker2').datetimepicker({
              locale: 'es',
              pickTime: false
          });
});

Factorial in numpy and scipy

    from numpy import prod

    def factorial(n):
        print prod(range(1,n+1))

or with mul from operator:

    from operator import mul

    def factorial(n):
        print reduce(mul,range(1,n+1))

or completely without help:

    def factorial(n):
        print reduce((lambda x,y: x*y),range(1,n+1))

Howto: Clean a mysql InnoDB storage engine?

The InnoDB engine does not store deleted data. As you insert and delete rows, unused space is left allocated within the InnoDB storage files. Over time, the overall space will not decrease, but over time the 'deleted and freed' space will be automatically reused by the DB server.

You can further tune and manage the space used by the engine through an manual re-org of the tables. To do this, dump the data in the affected tables using mysqldump, drop the tables, restart the mysql service, and then recreate the tables from the dump files.

How to read and write into file using JavaScript?

There are two ways to read and write a file using JavaScript

  1. Using JavaScript extensions

  2. Using a web page and Active X objects

How to show "if" condition on a sequence diagram?

If you paste

A.do() {
  if (condition1) {
   X.doSomething
  } else if (condition2) {
   Y.doSomethingElse
  } else {
   donotDoAnything
  }
}

onto https://www.zenuml.com. It will generate a diagram for you.If/else sequence diagram

unexpected T_VARIABLE, expecting T_FUNCTION

check that you entered a variable as argument with the '$' symbol

show all tables in DB2 using the LIST command

To get a list of tables for the current database in DB2 -->

Connect to the database:

db2 connect to DATABASENAME user USER using PASSWORD

Run this query:

db2 LIST TABLES

This is the equivalent of SHOW TABLES in MySQL.

You may need to execute 'set schema myschema' to the correct schema before you run the list tables command. By default upon login your schema is the same as your username - which often won't contain any tables. You can use 'values current schema' to check what schema you're currently set to.

Google Maps API v3: Can I setZoom after fitBounds?

If 'bounds_changed' is not firing correctly (sometimes Google doesn't seem to accept coordinates perfectly), then consider using 'center_changed' instead.

The 'center_changed' event fires every time fitBounds() is called, although it runs immediately and not necessarily after the map has moved.

In normal cases, 'idle' is still the best event listener, but this may help a couple people running into weird issues with their fitBounds() calls.

See google maps fitBounds callback

Can there exist two main methods in a Java program?

The answer is Yes, but you should consider the following 3 points.

  1. No two main method parameter should be the same

    Eg.

    • public static void main(int i)
    • public static void main(int i, int j)
    • public static void main(double j)
    • public static void main(String[] args)
  2. Java’s actual main method is the one with (String[] args), So the Actual execution starts from public static void main(String[] args), so the main method with (String[] args) is must in a class unless if it is not a child class.

  3. In order for other main methods to execute you need to call them from inside the (String[] args) main method.

Here is a detailed video about the same: https://www.youtube.com/watch?v=Qlhslsluhg4&feature=youtu.be

How to sort a List of objects by their date (java collections, List<Object>)

You're using Comparators incorrectly.

 Collections.sort(movieItems, new Comparator<Movie>(){
           public int compare (Movie m1, Movie m2){
               return m1.getDate().compareTo(m2.getDate());
           }
       });

The Web Application Project [...] is configured to use IIS. The Web server [...] could not be found.

Cause: The IISURL inside project.csproj is not correctly reflected in the project setting, and the virtual directory was not created.

Solution: Change the Project URL to correct PORT and create the Virtual Directory to make the missing PORT available.


Follow Below Steps:

Step 1: Right click on the project file to Edit the project.csproj file. enter image description here

Step 2: Search IIS and modify from <UseIIS>True</UseIIS> to <UseIIS>False</UseIIS> enter image description here

Step 3: Right Click Project to Reload the Project. After Reload successfully, right click Project and select Properties. enter image description here

Step 4: Locate Project URL option under Properties => Web enter image description here

Step 5: Change the Project URL to IIS URL indicated both on the Error Message and on the <IISURL>http://localhost:8086 </IISURL> from project.csproj file. Then Click Create Virtual Directory. Save All enter image description here enter image description here

Step 6: Redo Step 2 so it doesn't impact the remote codebase and the server deployment settings.

Missing MVC template in Visual Studio 2015

I had the same issue with the MVC template not appearing in VS2015.

I checked Web Developer Tools when originally installing. It was still checked when trying to Modify the install. I tried unchecking and updating the install but next time I went back to Modify, it was still checked. And still no MVC template.

I got it working by uninstalling: Microsoft ASP.NET Web Frameworks and Tools 2015 via the Programs and Features windows and re-installing. Here's the link for those who don't have it.

SQL Query Where Field DOES NOT Contain $x

What kind of field is this? The IN operator cannot be used with a single field, but is meant to be used in subqueries or with predefined lists:

-- subquery
SELECT a FROM x WHERE x.b NOT IN (SELECT b FROM y);
-- predefined list
SELECT a FROM x WHERE x.b NOT IN (1, 2, 3, 6);

If you are searching a string, go for the LIKE operator (but this will be slow):

-- Finds all rows where a does not contain "text"
SELECT * FROM x WHERE x.a NOT LIKE '%text%';

If you restrict it so that the string you are searching for has to start with the given string, it can use indices (if there is an index on that field) and be reasonably fast:

-- Finds all rows where a does not start with "text"
SELECT * FROM x WHERE x.a NOT LIKE 'text%';

What is the difference/usage of homebrew, macports or other package installation tools?

Currently, Macports has many more packages (~18.6 K) than there are Homebrew formulae (~3.1K), owing to its maturity. Homebrew is slowly catching up though.

Macport packages tend to be maintained by a single person.

Macports can keep multiple versions of packages around, and you can enable or disable them to test things out. Sometimes this list can get corrupted and you have to manually edit it to get things back in order, although this is not too hard.

Both package managers will ask to be regularly updated. This can take some time.

Note: you can have both package managers on your system! It is not one or the other. Brew might complain but Macports won't.

Also, if you are dealing with python or ruby packages, use a virtual environment wherever possible.

ReactJS: "Uncaught SyntaxError: Unexpected token <"

JSTransform is deprecated , please use babel instead.

<script type="text/babel" src="./lander.js"></script>

What is meant by immutable?

"immutable" means you cannot change value. If you have an instance of String class, any method you call which seems to modify the value, will actually create another String.

String foo = "Hello";
foo.substring(3);
<-- foo here still has the same value "Hello"

To preserve changes you should do something like this foo = foo.sustring(3);

Immutable vs mutable can be funny when you work with collections. Think about what will happen if you use mutable object as a key for map and then change the value (tip: think about equals and hashCode).

How do I send email with JavaScript without opening the mail client?

Well, PHP can do this easily.

It can be done with the PHP mail() function. Here's what a simple function would look like:

<?php     
$to_email = '[email protected]';
$subject = 'Testing PHP Mail';
$message = 'This mail is sent using the PHP mail function';
$headers = 'From: [email protected]';
mail($to_email,$subject,$message,$headers);
?>

This will send a background e-mail to the recipient specified in the $to_email.

The above example uses hard coded values in the source code for the email address and other details for simplicity.

Let’s assume you have to create a contact us form for users fill in the details and then submit.

  1. Users can accidently or intentional inject code in the headers which can result in sending spam mail
  2. To protect your system from such attacks, you can create a custom function that sanitizes and validates the values before the mail is sent.

Let’s create a custom function that validates and sanitizes the email address using the filter_var() built in function.

Here's an example code:

<?php 
function sanitize_my_email($field) {
    $field = filter_var($field, FILTER_SANITIZE_EMAIL);
    if (filter_var($field, FILTER_VALIDATE_EMAIL)) {
        return true;
    } else {
        return false;
    }
}
$to_email = '[email protected]';
$subject = 'Testing PHP Mail';
$message = 'This mail is sent using the PHP mail ';
$headers = 'From: [email protected]';
//check if the email address is invalid $secure_check
$secure_check = sanitize_my_email($to_email);
if ($secure_check == false) {
    echo "Invalid input";
} else { //send email 
    mail($to_email, $subject, $message, $headers);
    echo "This email is sent using PHP Mail";
}
?>

We will now let this be a separate PHP file, for example sendmail.php.

Then, will use this file on form submission, using the action attribute of the form, like:

<form action="sendmail.php" method="post">
   <input type="text" value="Your Name: ">
   <input type="password" value="Set Up A Passworrd">
   <input type="submit" value="Signup">
   <input type="reset" value="Reset Form">
</form>

Hope I could help

Install Qt on Ubuntu

The ubuntu package name is qt5-default, not qt.

How to insert a character in a string at a certain position?

String.format("%0d.%02d", d / 100, d % 100);

How to truncate float values?

def precision(value, precision):
    """
    param: value: takes a float
    param: precision: int, number of decimal places
    returns a float
    """
    x = 10.0**precision
    num = int(value * x)/ x
    return num
precision(1.923328437452, 3)

1.923

Storing data into list with class

You are attempting to call

List<EmailData>.Add(string,string,string)
. Try this:

lstemail.add(new EmailData{ FirstName="John", LastName="Smith", Location="Los Angeles"});

Deserializing JSON data to C# using JSON.NET

I found my I had built my object incorrectly. I used http://json2csharp.com/ to generate me my object class from the JSON. Once I had the correct Oject I was able to cast without issue. Norbit, Noob mistake. Thought I'd add it in case you have the same issue.

How to get current location in Android

I'm using this tutorial and it works nicely for my application.

In my activity I put this code:

GPSTracker tracker = new GPSTracker(this);
    if (!tracker.canGetLocation()) {
        tracker.showSettingsAlert();
    } else {
        latitude = tracker.getLatitude();
        longitude = tracker.getLongitude();
    }

also check if your emulator runs with Google API

Updating an object with setState in React

I know there are a lot of answers here, but I'm surprised none of them create a copy of the new object outside of setState, and then simply setState({newObject}). Clean, concise and reliable. So in this case:

_x000D_
_x000D_
const jasper = { ...this.state.jasper, name: 'someothername' }_x000D_
this.setState(() => ({ jasper }))
_x000D_
_x000D_
_x000D_

Or for a dynamic property (very useful for forms)

_x000D_
_x000D_
const jasper = { ...this.state.jasper, [VarRepresentingPropertyName]: 'new value' }_x000D_
this.setState(() => ({ jasper }))
_x000D_
_x000D_
_x000D_

What is the $$hashKey added to my JSON.stringify result

It comes with the ng-repeat directive usually. To do dom manipulation AngularJS flags objects with special id.

This is common with Angular. For example if u get object with ngResource your object will embed all the resource API and you'll see methods like $save, etc. With cookies too AngularJS will add a property __ngDebug.

Array initializing in Scala

Can also do more dynamic inits with fill, e.g.

Array.fill(10){scala.util.Random.nextInt(5)} 

==>

Array[Int] = Array(0, 1, 0, 0, 3, 2, 4, 1, 4, 3)

Val and Var in Kotlin

In Kotlin we use var to declare a variable. It is mutable. We can change, reassign variables. Example,

fun main(args : Array<String>){
    var x = 10
    println(x)

    x = 100 // vars can reassign.
    println(x)
}

We use val to declare constants. They are immutable. Unable to change, reassign vals. val is something similar to final variables in java. Example,

fun main(args : Array<String>){
    val y = 10
    println(y)

    y = 100 // vals can't reassign (COMPILE ERROR!).
    println(y)
}

How to use a switch case 'or' in PHP

Match expression (PHP 8)

PHP 8 RFC introduced a new match expression that is similar to switch but with the shorter syntax:

  • doesn't require break statements
  • combine conditions using a comma
  • returns a value

Example:

match ($value) {
  0 => '0',
  1, 2 => "1 or 2",
  default => "3",
}

JS Client-Side Exif Orientation: Rotate and Mirror JPEG Images

Wunderbart's post worked for me combined with statler's improvements. Adding a few more comments and syntax cleanup, and also passing back the orientation value and I have the following code feel free to use. Just call readImageFile() function below and you get back the transformed image and the original orientation.

const JpegOrientation = [
    "NOT_JPEG",
    "NORMAL",
    "FLIP-HORIZ",
    "ROT180",
    "FLIP-HORIZ-ROT180",
    "FLIP-HORIZ-ROT270",
    "ROT270",
    "FLIP-HORIZ-ROT90",
    "ROT90"
];


//Provided a image file, determines the orientation of the file based on the EXIF information.
//Calls the "callback" function with an index into the JpegOrientation array. 
//If the image is not a JPEG, returns 0. If  the orientation value cannot be read (corrupted file?) return -1.
function getOrientation(file, callback) {
    
    const reader = new FileReader();
    reader.onload = (e) => {

        const view = new DataView(e.target.result);
        
        if (view.getUint16(0, false) !== 0xFFD8) {
            return callback(0);  //NOT A JPEG FILE
        }
        
        const length = view.byteLength;
        let offset = 2;
        while (offset < length) {
            
            if (view.getUint16(offset+2, false) <= 8)   //unknown?
                return callback(-1);
            
            const marker = view.getUint16(offset, false);
            offset += 2;
            if (marker === 0xFFE1) {
                
                if (view.getUint32(offset += 2, false) !== 0x45786966) 
                    return callback(-1); //unknown?
                

                const little = view.getUint16(offset += 6, false) === 0x4949;
                offset += view.getUint32(offset + 4, little);
                const tags = view.getUint16(offset, little);
                offset += 2;
                for (var i = 0; i < tags; i++) {
                    if (view.getUint16(offset + (i * 12), little) === 0x0112) {
                        return callback(view.getUint16(offset + (i * 12) + 8, little));   //found orientation code
                    }
                }
            }
            else if ((marker & 0xFF00) !== 0xFF00) {
                break;
            }
            else { 
                offset += view.getUint16(offset, false);
            }
        }
        
        return callback(-1); //unknown?
    };
    reader.readAsArrayBuffer(file);
}

//Takes a jpeg image file as base64 and transforms it back to original, providing the
//transformed image in callback.  If the image is not a jpeg or is already in normal orientation,
//just calls the callback directly with the source.
//Set type to the desired output type if transformed, default is image/jpeg for speed.
function resetOrientation(srcBase64, srcOrientation, callback, type = "image/jpeg") {
    
    if (srcOrientation <= 1) {  //no transform needed
        callback(srcBase64);
        return;
    }
    
    const img = new Image();    

    img.onload = () => {
        const width = img.width;
        const height = img.height;
        const canvas = document.createElement('canvas');
        const ctx = canvas.getContext("2d");

        // set proper canvas dimensions before transform & export
        if (4 < srcOrientation && srcOrientation < 9) {
            canvas.width = height;
            canvas.height = width;
        } else {
            canvas.width = width;
            canvas.height = height;
        }

        // transform context before drawing image
        switch (srcOrientation) {
              
              //case 1: normal, no transform needed
              
              case 2:  
                  ctx.transform(-1, 0, 0, 1, width, 0); 
                  break;
              case 3:
                  ctx.transform(-1, 0, 0, -1, width, height); 
                  break;
              case 4: 
                  ctx.transform(1, 0, 0, -1, 0, height); 
                  break;
              case 5: 
                  ctx.transform(0, 1, 1, 0, 0, 0); 
                  break;
              case 6: 
                  ctx.transform(0, 1, -1, 0, height, 0); 
                  break;
              case 7: 
                  ctx.transform(0, -1, -1, 0, height, width); 
                  break;
              case 8: 
                  ctx.transform(0, -1, 1, 0, 0, width); 
                  break;
              default: 
                  break;
        }

        // draw image
        ctx.drawImage(img, 0, 0);

        //export base64
        callback(canvas.toDataURL(type), srcOrientation);
    };

    img.src = srcBase64;
};


//Read an image file, providing the returned data to callback. If the image is jpeg
//and is transformed according to EXIF info, transform it first.
//The callback function receives the image data and the orientation value (index into JpegOrientation)
export function readImageFile(file, callback) {

    getOrientation(file, (orientation) => {

        console.log("Read file \"" + file.name + "\" with orientation: " + JpegOrientation[orientation]);

        const reader = new FileReader();
        reader.onload = () => {  //when reading complete

            const img = reader.result;
            resetOrientation(img, orientation, callback);
        };
        reader.readAsDataURL(file);  //start read
        
    });
}

How to inspect Javascript Objects

Use console.dir(object) and the Firebug plugin

HTML5 Canvas and Anti-aliasing

Here's a workaround that requires you to draw lines pixel by pixel, but will prevent anti aliasing.

// some helper functions
// finds the distance between points
function DBP(x1,y1,x2,y2) {
    return Math.sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1));
}
// finds the angle of (x,y) on a plane from the origin
function getAngle(x,y) { return Math.atan(y/(x==0?0.01:x))+(x<0?Math.PI:0); }
// the function
function drawLineNoAliasing(ctx, sx, sy, tx, ty) {
    var dist = DBP(sx,sy,tx,ty); // length of line
    var ang = getAngle(tx-sx,ty-sy); // angle of line
    for(var i=0;i<dist;i++) {
        // for each point along the line
        ctx.fillRect(Math.round(sx + Math.cos(ang)*i), // round for perfect pixels
                     Math.round(sy + Math.sin(ang)*i), // thus no aliasing
                     1,1); // fill in one pixel, 1x1
    }
}

Basically, you find the length of the line, and step by step traverse that line, rounding each position, and filling in a pixel.

Call it with

var context = cv.getContext("2d");
drawLineNoAliasing(context, 20,30,20,50); // line from (20,30) to (20,50)

Can I redirect the stdout in python into some sort of string buffer?

Starting with Python 2.6 you can use anything implementing the TextIOBase API from the io module as a replacement. This solution also enables you to use sys.stdout.buffer.write() in Python 3 to write (already) encoded byte strings to stdout (see stdout in Python 3). Using StringIO wouldn't work then, because neither sys.stdout.encoding nor sys.stdout.buffer would be available.

A solution using TextIOWrapper:

import sys
from io import TextIOWrapper, BytesIO

# setup the environment
old_stdout = sys.stdout
sys.stdout = TextIOWrapper(BytesIO(), sys.stdout.encoding)

# do something that writes to stdout or stdout.buffer

# get output
sys.stdout.seek(0)      # jump to the start
out = sys.stdout.read() # read output

# restore stdout
sys.stdout.close()
sys.stdout = old_stdout

This solution works for Python 2 >= 2.6 and Python 3.

Please note that our new sys.stdout.write() only accepts unicode strings and sys.stdout.buffer.write() only accepts byte strings. This might not be the case for old code, but is often the case for code that is built to run on Python 2 and 3 without changes, which again often makes use of sys.stdout.buffer.

You can build a slight variation that accepts unicode and byte strings for write():

class StdoutBuffer(TextIOWrapper):
    def write(self, string):
        try:
            return super(StdoutBuffer, self).write(string)
        except TypeError:
            # redirect encoded byte strings directly to buffer
            return super(StdoutBuffer, self).buffer.write(string)

You don't have to set the encoding of the buffer the sys.stdout.encoding, but this helps when using this method for testing/comparing script output.

How to hide a div from code (c#)

if your div has the runat set to server, you surely can do a myDiv.Visible = false in your Page_PreRender event for example.

if you need help on using the session, have a look in msdn, it's very easy.

How to read a single char from the console in Java (as the user types it)?

There is no portable way to read raw characters from a Java console.

Some platform-dependent workarounds have been presented above. But to be really portable, you'd have to abandon console mode and use a windowing mode, e.g. AWT or Swing.

How to remove trailing and leading whitespace for user-provided input in a batch file?

You need to enable delayed expansion. Try this:

@echo off
setlocal enabledelayedexpansion
:blah
set /p input=:
echo."%input%"
for /f "tokens=* delims= " %%a in ("%input%") do set input=%%a
for /l %%a in (1,1,100) do if "!input:~-1!"==" " set input=!input:~0,-1!
echo."%input%"
pause
goto blah

How do I express "if value is not empty" in the VBA language?

I think the solution of this issue can be some how easier than we imagine. I have simply used the expression Not Null and it worked fine.

Browser("micclass").Page("micclass").WebElement("Test").CheckProperty "innertext", Not Null

How to assign string to bytes array

Arrays are values... slices are more like pointers. That is [n]type is not compatible with []type as they are fundamentally two different things. You can get a slice that points to an array by using arr[:] which returns a slice that has arr as it's backing storage.

One way to convert a slice of for example []byte to [20]byte is to actually allocate a [20]byte which you can do by using var [20]byte (as it's a value... no make needed) and then copy data into it:

buf := make([]byte, 10)
var arr [10]byte
copy(arr[:], buf)

Essentially what a lot of other answers get wrong is that []type is NOT an array.

[n]T and []T are completely different things!

When using reflect []T is not of kind Array but of kind Slice and [n]T is of kind Array.

You also can't use map[[]byte]T but you can use map[[n]byte]T.

This can sometimes be cumbersome because a lot of functions operate for example on []byte whereas some functions return [n]byte (most notably the hash functions in crypto/*). A sha256 hash for example is [32]byte and not []byte so when beginners try to write it to a file for example:

sum := sha256.Sum256(data)
w.Write(sum)

they will get an error. The correct way of is to use

w.Write(sum[:])

However, what is it that you want? Just accessing the string bytewise? You can easily convert a string to []byte using:

bytes := []byte(str)

but this isn't an array, it's a slice. Also, byte != rune. In case you want to operate on "characters" you need to use rune... not byte.

Convert an object to an XML string

This is my solution, for any list object you can use this code for convert to xml layout. KeyFather is your principal tag and KeySon is where start your Forech.

public string BuildXml<T>(ICollection<T> anyObject, string keyFather, string keySon)
    {
        var settings = new XmlWriterSettings
        {
            Indent = true
        };
        PropertyDescriptorCollection props = TypeDescriptor.GetProperties(typeof(T));
        StringBuilder builder = new StringBuilder();
        using (XmlWriter writer = XmlWriter.Create(builder, settings))
        {
            writer.WriteStartDocument();
            writer.WriteStartElement(keyFather);
            foreach (var objeto in anyObject)
            {
                writer.WriteStartElement(keySon);
                foreach (PropertyDescriptor item in props)
                {
                    writer.WriteStartElement(item.DisplayName);
                    writer.WriteString(props[item.DisplayName].GetValue(objeto).ToString());
                    writer.WriteEndElement();
                }
                writer.WriteEndElement();
            }
            writer.WriteFullEndElement();
            writer.WriteEndDocument();
            writer.Flush();
            return builder.ToString();
        }
    }

How can I install a package with go get?

Command go

Download and install packages and dependencies

Usage:

go get [-d] [-f] [-t] [-u] [-v] [-fix] [-insecure] [build flags] [packages]

Get downloads the packages named by the import paths, along with their dependencies. It then installs the named packages, like 'go install'.

The -d flag instructs get to stop after downloading the packages; that is, it instructs get not to install the packages.

The -f flag, valid only when -u is set, forces get -u not to verify that each package has been checked out from the source control repository implied by its import path. This can be useful if the source is a local fork of the original.

The -fix flag instructs get to run the fix tool on the downloaded packages before resolving dependencies or building the code.

The -insecure flag permits fetching from repositories and resolving custom domains using insecure schemes such as HTTP. Use with caution.

The -t flag instructs get to also download the packages required to build the tests for the specified packages.

The -u flag instructs get to use the network to update the named packages and their dependencies. By default, get uses the network to check out missing packages but does not use it to look for updates to existing packages.

The -v flag enables verbose progress and debug output.

Get also accepts build flags to control the installation. See 'go help build'.

When checking out a new package, get creates the target directory GOPATH/src/. If the GOPATH contains multiple entries, get uses the first one. For more details see: 'go help gopath'.

When checking out or updating a package, get looks for a branch or tag that matches the locally installed version of Go. The most important rule is that if the local installation is running version "go1", get searches for a branch or tag named "go1". If no such version exists it retrieves the default branch of the package.

When go get checks out or updates a Git repository, it also updates any git submodules referenced by the repository.

Get never checks out or updates code stored in vendor directories.

For more about specifying packages, see 'go help packages'.

For more about how 'go get' finds source code to download, see 'go help importpath'.

This text describes the behavior of get when using GOPATH to manage source code and dependencies. If instead the go command is running in module-aware mode, the details of get's flags and effects change, as does 'go help get'. See 'go help modules' and 'go help module-get'.

See also: go build, go install, go clean.


For example, showing verbose output,

$ go get -v github.com/capotej/groupcache-db-experiment/...
github.com/capotej/groupcache-db-experiment (download)
github.com/golang/groupcache (download)
github.com/golang/protobuf (download)
github.com/capotej/groupcache-db-experiment/api
github.com/capotej/groupcache-db-experiment/client
github.com/capotej/groupcache-db-experiment/slowdb
github.com/golang/groupcache/consistenthash
github.com/golang/protobuf/proto
github.com/golang/groupcache/lru
github.com/capotej/groupcache-db-experiment/dbserver
github.com/capotej/groupcache-db-experiment/cli
github.com/golang/groupcache/singleflight
github.com/golang/groupcache/groupcachepb
github.com/golang/groupcache
github.com/capotej/groupcache-db-experiment/frontend
$ 

Is there a function to split a string in PL/SQL?

There is apex_util.string_to_table - see my answer to this question.

Also, prior to the existence of the above function, I once posted a solution here on my blog.

Update

In later versions of APEX, apex_util.string_to_table is deprecated, and a similar function apex_string.split is preferred.

How to sort multidimensional array by column?

sorted(list, key=lambda x: x[1])

Note: this works on time variable too.

Get PostGIS version

Other way to get the minor version is:

SELECT extversion
FROM pg_catalog.pg_extension
WHERE extname='postgis'

Get value of multiselect box using jQuery or pure JS

var data=[];
var $el=$("#my-select");
$el.find('option:selected').each(function(){
    data.push({value:$(this).val(),text:$(this).text()});
});
console.log(data)

How can javascript upload a blob?

Try this

var fd = new FormData();
fd.append('fname', 'test.wav');
fd.append('data', soundBlob);
$.ajax({
    type: 'POST',
    url: '/upload.php',
    data: fd,
    processData: false,
    contentType: false
}).done(function(data) {
       console.log(data);
});

You need to use the FormData API and set the jQuery.ajax's processData and contentType to false.

LINQ Group By into a Dictionary Object

For @atari2600, this is what the answer would look like using ToLookup in lambda syntax:

var x = listOfCustomObjects
    .GroupBy(o => o.PropertyName)
    .ToLookup(customObject => customObject);

Basically, it takes the IGrouping and materializes it for you into a dictionary of lists, with the values of PropertyName as the key.

Escape regex special characters in a Python string

If you only want to replace some characters you could use this:

import re

print re.sub(r'([\.\\\+\*\?\[\^\]\$\(\)\{\}\!\<\>\|\:\-])', r'\\\1', "example string.")

Displaying the build date

I used Abdurrahim's suggestion. However, it seemed to give a weird time format and also added the abbreviation for the day as part of the build date; example: Sun 12/24/2017 13:21:05.43. I only needed just the date so I had to eliminate the rest using substring.

After adding the echo %date% %time% > "$(ProjectDir)\Resources\BuildDate.txt"to the pre-build event, I just did the following:

string strBuildDate = YourNamespace.Properties.Resources.BuildDate;
string strTrimBuildDate = strBuildDate.Substring(4).Remove(10);

The good news here is that it worked.

Python: SyntaxError: keyword can't be an expression

sum.up is not a valid keyword argument name. Keyword arguments must be valid identifiers. You should look in the documentation of the library you are using how this argument really is called – maybe sum_up?

Unioning two tables with different number of columns

I came here and followed above answer. But mismatch in the Order of data type caused an error. The below description from another answer will come handy.

Are the results above the same as the sequence of columns in your table? because oracle is strict in column orders. this example below produces an error:

create table test1_1790 (
col_a varchar2(30),
col_b number,
col_c date);

create table test2_1790 (
col_a varchar2(30),
col_c date,
col_b number);

select * from test1_1790
union all
select * from test2_1790;

ORA-01790: expression must have same datatype as corresponding expression

As you see the root cause of the error is in the mismatching column ordering that is implied by the use of * as column list specifier. This type of errors can be easily avoided by entering the column list explicitly:

select col_a, col_b, col_c from test1_1790 union all select col_a, col_b, col_c from test2_1790; A more frequent scenario for this error is when you inadvertently swap (or shift) two or more columns in the SELECT list:

select col_a, col_b, col_c from test1_1790
union all
select col_a, col_c, col_b from test2_1790;

OR if the above does not solve your problem, how about creating an ALIAS in the columns like this: (the query is not the same as yours but the point here is how to add alias in the column.)

SELECT id_table_a, 
       desc_table_a, 
       table_b.id_user as iUserID, 
       table_c.field as iField
UNION
SELECT id_table_a, 
       desc_table_a, 
       table_c.id_user as iUserID, 
       table_c.field as iField

Fragment MyFragment not attached to Activity

I faced similar issues when the application settings activity with the loaded preferences was visible. If I would change one of the preferences and then make the display content rotate and change the preference again, it would crash with a message that the fragment (my Preferences class) was not attached to an activity.

When debugging it looked like the onCreate() Method of the PreferencesFragment was being called twice when the display content rotated. That was strange enough already. Then I added the isAdded() check outside of the block where it would indicate the crash and it solved the issue.

Here is the code of the listener that updates the preferences summary to show the new entry. It is located in the onCreate() method of my Preferences class which extends the PreferenceFragment class:

public static class Preferences extends PreferenceFragment {
    SharedPreferences.OnSharedPreferenceChangeListener listener;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        // ...
        listener = new SharedPreferences.OnSharedPreferenceChangeListener() {
            @Override
            public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
                // check if the fragment has been added to the activity yet (necessary to avoid crashes)
                if (isAdded()) {
                    // for the preferences of type "list" set the summary to be the entry of the selected item
                    if (key.equals(getString(R.string.pref_fileviewer_textsize))) {
                        ListPreference listPref = (ListPreference) findPreference(key);
                        listPref.setSummary("Display file content with a text size of " + listPref.getEntry());
                    } else if (key.equals(getString(R.string.pref_fileviewer_segmentsize))) {
                        ListPreference listPref = (ListPreference) findPreference(key);
                        listPref.setSummary("Show " + listPref.getEntry() + " bytes of a file at once");
                    }
                }
            }
        };
        // ...
    }

I hope this will help others!

how to convert `content://media/external/images/media/Y` to `file:///storage/sdcard0/Pictures/X.jpg` in android?

If you just want the bitmap, This too works

InputStream inputStream = mContext.getContentResolver().openInputStream(uri);
Bitmap bmp = BitmapFactory.decodeStream(inputStream);
if( inputStream != null ) inputStream.close();

sample uri : content://media/external/images/media/12345

Bootstrap 4 - Inline List?

.list-inline class in bootstrap is a Inline Unordered List.

If you want to create a horizontal menu using ordered or unordered list you need to place all list items in a single line i.e. side by side. You can do this by simply applying the class

<div class="list-inline">
    <a href="#" class="list-inline-item">First item</a>
    <a href="#" class="list-inline-item">Secound item</a>
    <a href="#" class="list-inline-item">Third item</a>
  </div>

Background color on input type=button :hover state sticks in IE

You need to make sure images come first and put in a comma after the background image call. then it actually does work:

    background:url(egg.png) no-repeat 70px 2px #82d4fe; /* Old browsers */
background:url(egg.png) no-repeat 70px 2px, -moz-linear-gradient(top, #82d4fe 0%, #1db2ff 78%) ; /* FF3.6+ */
background:url(egg.png) no-repeat 70px 2px, -webkit-gradient(linear, left top, left bottom, color-stop(0%,#82d4fe), color-stop(78%,#1db2ff)); /* Chrome,Safari4+ */
background:url(egg.png) no-repeat 70px 2px, -webkit-linear-gradient(top, #82d4fe 0%,#1db2ff 78%); /* Chrome10+,Safari5.1+ */
background:url(egg.png) no-repeat 70px 2px, -o-linear-gradient(top, #82d4fe 0%,#1db2ff 78%); /* Opera11.10+ */
background:url(egg.png) no-repeat 70px 2px, -ms-linear-gradient(top, #82d4fe 0%,#1db2ff 78%); /* IE10+ */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#82d4fe', endColorstr='#1db2ff',GradientType=0 ); /* IE6-9 */
background:url(egg.png) no-repeat 70px 2px, linear-gradient(top, #82d4fe 0%,#1db2ff 78%); /* W3C */

Set auto height and width in CSS/HTML for different screen sizes

Using bootstrap with a little bit of customization, the following seems to work for me:

I need 3 partitions in my container and I tried this:

CSS:

.row.content {height: 100%; width:100%; position: fixed; }
.sidenav {
  padding-top: 20px;
  border: 1px solid #cecece;
  height: 100%;
}
.midnav {
  padding: 0px;
}

HTML:

  <div class="container-fluid text-center"> 
    <div class="row content">
    <div class="col-md-2 sidenav text-left">Some content 1</div>
    <div class="col-md-9 midnav text-left">Some content 2</div>
    <div class="col-md-1 sidenav text-center">Some content 3</div>
    </div>
  </div>

Randomize numbers with jQuery?

Others have answered the question, but just for the fun of it, here is a visual dice throwing example, using the Math.random javascript method, a background image and some recursive timeouts.

http://www.jsfiddle.net/zZUgF/3/

Declaring abstract method in TypeScript

No, no, no! Please do not try to make your own 'abstract' classes and methods when the language does not support that feature; the same goes for any language feature you wish a given language supported. There is no correct way to implement abstract methods in TypeScript. Just structure your code with naming conventions such that certain classes are never directly instantiated, but without explicitly enforcing this prohibition.

Also, the example above is only going to provide this enforcement at run time, NOT at compile time, as you would expect in Java/C#.

Specifying java version in maven - differences between properties and compiler plugin

How to specify the JDK version?

Use any of three ways: (1) Spring Boot feature, or use Maven compiler plugin with either (2) source & target or (3) with release.

Spring Boot

  1. <java.version> is not referenced in the Maven documentation.
    It is a Spring Boot specificity.
    It allows to set the source and the target java version with the same version such as this one to specify java 1.8 for both :

    1.8

Feel free to use it if you use Spring Boot.

maven-compiler-plugin with source & target

  1. Using maven-compiler-plugin or maven.compiler.source/maven.compiler.target properties are equivalent.

That is indeed :

<plugins>
    <plugin>    
        <artifactId>maven-compiler-plugin</artifactId>
        <configuration>
            <source>1.8</source>
            <target>1.8</target>
        </configuration>
    </plugin>
</plugins>

is equivalent to :

<properties>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
</properties>

according to the Maven documentation of the compiler plugin since the <source> and the <target> elements in the compiler configuration use the properties maven.compiler.source and maven.compiler.target if they are defined.

source

The -source argument for the Java compiler.
Default value is: 1.6.
User property is: maven.compiler.source.

target

The -target argument for the Java compiler.
Default value is: 1.6.
User property is: maven.compiler.target.

About the default values for source and target, note that since the 3.8.0 of the maven compiler, the default values have changed from 1.5 to 1.6.

maven-compiler-plugin with release instead of source & target

  1. The maven-compiler-plugin 3.6 and later versions provide a new way :

    org.apache.maven.plugins maven-compiler-plugin 3.8.0 9

You could also declare just :

<properties>
    <maven.compiler.release>9</maven.compiler.release>
</properties>

But at this time it will not work as the maven-compiler-plugin default version you use doesn't rely on a recent enough version.

The Maven release argument conveys release : a new JVM standard option that we could pass from Java 9 :

Compiles against the public, supported and documented API for a specific VM version.

This way provides a standard way to specify the same version for the source, the target and the bootstrap JVM options.
Note that specifying the bootstrap is a good practice for cross compilations and it will not hurt if you don't make cross compilations either.


Which is the best way to specify the JDK version?

The first way (<java.version>) is allowed only if you use Spring Boot.

For Java 8 and below :

About the two other ways : valuing the maven.compiler.source/maven.compiler.target properties or using the maven-compiler-plugin, you can use one or the other. It changes nothing in the facts since finally the two solutions rely on the same properties and the same mechanism : the maven core compiler plugin.

Well, if you don't need to specify other properties or behavior than Java versions in the compiler plugin, using this way makes more sense as this is more concise:

<properties>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
</properties>

From Java 9 :

The release argument (third point) is a way to strongly consider if you want to use the same version for the source and the target.

What happens if the version differs between the JDK in JAVA_HOME and which one specified in the pom.xml?

It is not a problem if the JDK referenced by the JAVA_HOME is compatible with the version specified in the pom but to ensure a better cross-compilation compatibility think about adding the bootstrap JVM option with as value the path of the rt.jar of the target version.

An important thing to consider is that the source and the target version in the Maven configuration should not be superior to the JDK version referenced by the JAVA_HOME.
A older version of the JDK cannot compile with a more recent version since it doesn't know its specification.

To get information about the source, target and release supported versions according to the used JDK, please refer to java compilation : source, target and release supported versions.


How handle the case of JDK referenced by the JAVA_HOME is not compatible with the java target and/or source versions specified in the pom?

For example, if your JAVA_HOME refers to a JDK 1.7 and you specify a JDK 1.8 as source and target in the compiler configuration of your pom.xml, it will be a problem because as explained, the JDK 1.7 doesn't know how to compile with.
From its point of view, it is an unknown JDK version since it was released after it.
In this case, you should configure the Maven compiler plugin to specify the JDK in this way :

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <configuration>
        <source>1.8</source>
        <target>1.8</target>
        <compilerVersion>1.8</compilerVersion>      
        <fork>true</fork>
        <executable>D:\jdk1.8\bin\javac</executable>                
    </configuration>
</plugin>

You could have more details in examples with maven compiler plugin.


It is not asked but cases where that may be more complicated is when you specify source but not target. It may use a different version in target according to the source version. Rules are particular : you can read about them in the Cross-Compilation Options part.


Why the compiler plugin is traced in the output at the execution of the Maven package goal even if you don't specify it in the pom.xml?

To compile your code and more generally to perform all tasks required for a maven goal, Maven needs tools. So, it uses core Maven plugins (you recognize a core Maven plugin by its groupId : org.apache.maven.plugins) to do the required tasks : compiler plugin for compiling classes, test plugin for executing tests, and so for... So, even if you don't declare these plugins, they are bound to the execution of the Maven lifecycle.
At the root dir of your Maven project, you can run the command : mvn help:effective-pom to get the final pom effectively used. You could see among other information, attached plugins by Maven (specified or not in your pom.xml), with the used version, their configuration and the executed goals for each phase of the lifecycle.

In the output of the mvn help:effective-pom command, you could see the declaration of these core plugins in the <build><plugins> element, for example :

...
<plugin>
   <artifactId>maven-clean-plugin</artifactId>
   <version>2.5</version>
   <executions>
     <execution>
       <id>default-clean</id>
       <phase>clean</phase>
       <goals>
         <goal>clean</goal>
       </goals>
     </execution>
   </executions>
 </plugin>
 <plugin>
   <artifactId>maven-resources-plugin</artifactId>
   <version>2.6</version>
   <executions>
     <execution>
       <id>default-testResources</id>
       <phase>process-test-resources</phase>
       <goals>
         <goal>testResources</goal>
       </goals>
     </execution>
     <execution>
       <id>default-resources</id>
       <phase>process-resources</phase>
       <goals>
         <goal>resources</goal>
       </goals>
     </execution>
   </executions>
 </plugin>
 <plugin>
   <artifactId>maven-compiler-plugin</artifactId>
   <version>3.1</version>
   <executions>
     <execution>
       <id>default-compile</id>
       <phase>compile</phase>
       <goals>
         <goal>compile</goal>
       </goals>
     </execution>
     <execution>
       <id>default-testCompile</id>
       <phase>test-compile</phase>
       <goals>
         <goal>testCompile</goal>
       </goals>
     </execution>
   </executions>
 </plugin>
  ...

You can have more information about it in the introduction of the Maven lifeycle in the Maven documentation.

Nevertheless, you can declare these plugins when you want to configure them with other values as default values (for example, you did it when you declared the maven-compiler plugin in your pom.xml to adjust the JDK version to use) or when you want to add some plugin executions not used by default in the Maven lifecycle.

How to show text on image when hovering?

HTML
<img id="close" className="fa fa-close" src="" alt="" title="Close Me" />

CSS
#close[title]:hover:after {
  color: red;
  content: attr(title);
  position: absolute;
  left: 50px;
}

Change bar plot colour in geom_bar with ggplot2 in r

If you want all the bars to get the same color (fill), you can easily add it inside geom_bar.

ggplot(data=df, aes(x=c1+c2/2, y=c3)) + 
geom_bar(stat="identity", width=c2, fill = "#FF6666")

enter image description here

Add fill = the_name_of_your_var inside aes to change the colors depending of the variable :

c4 = c("A", "B", "C")
df = cbind(df, c4)
ggplot(data=df, aes(x=c1+c2/2, y=c3, fill = c4)) + 
geom_bar(stat="identity", width=c2)

enter image description here

Use scale_fill_manual() if you want to manually the change of colors.

ggplot(data=df, aes(x=c1+c2/2, y=c3, fill = c4)) + 
geom_bar(stat="identity", width=c2) + 
scale_fill_manual("legend", values = c("A" = "black", "B" = "orange", "C" = "blue"))

enter image description here

Make xargs handle filenames that contain spaces

Dick.Guertin's answer [1] suggested that one could escape the spaces in a filename is a valuable alternative to other solutions suggested here (such as using a null character as a separator rather than whitespace). But it could be simpler - you don't really need a unique character. You can just have sed add the escaped spaces directly:

ls | grep ' ' | sed 's| |\\ |g' | xargs ...

Furthermore, the grep is only necessary if you only want files with spaces in the names. More generically (e.g., when processing a batch of files some of which have spaces, some not), just skip the grep:

ls | sed 's| |\\ |g' | xargs ...

Then, of course, the filename may have other whitespace than blanks (e.g., a tab):

ls | sed -r 's|[[:blank:]]|\\\1|g' | xargs ...

That assumes you have a sed that supports -r (extended regex) such as GNU sed or recent versions of bsd sed (e.g., FreeBSD which originally spelled the option "-E" before FreeBSD 8 and supports both -r & -E for compatibility through FreeBSD 11 at least). Otherwise you can use a basic regex character class bracket expression and manually enter the space and tab characters in the [] delimiters.

[1] This is perhaps more appropriate as a comment or an edit to that answer, but at the moment I do not have enough reputation to comment and can only suggest edits. Since the latter forms above (without the grep) alters the behavior of Dick.Guertin's original answer, a direct edit is perhaps not appropriate anyway.

What's the difference between all the Selection Segues?

For those who prefer a bit more practical learning, select the segue in dock, open the attribute inspector and switch between different kinds of segues (dropdown "Kind"). This will reveal options specific for each of them: for example you can see that "present modally" allows you to choose a transition type etc.

How to make ng-repeat filter out duplicate results

this code works for me.

app.filter('unique', function() {

  return function (arr, field) {
    var o = {}, i, l = arr.length, r = [];
    for(i=0; i<l;i+=1) {
      o[arr[i][field]] = arr[i];
    }
    for(i in o) {
      r.push(o[i]);
    }
    return r;
  };
})

and then

var colors=$filter('unique')(items,"color");

Very Simple Image Slider/Slideshow with left and right button. No autoplay

After reading your comment on my previous answer I thought I might put this as a separate answer.

Although I appreciate your approach of trying to do it manually to get a better grasp on jQuery I do still emphasise the merit in using existing frameworks.

That said, here is a solution. I've modified some of your css and and HTML just to make it easier for me to work with

WORKING JS FIDDLE - http://jsfiddle.net/HsEne/15/

This is the jQuery

$(document).ready(function(){
$('.sp').first().addClass('active');
$('.sp').hide();    
$('.active').show();

    $('#button-next').click(function(){

    $('.active').removeClass('active').addClass('oldActive');    
                   if ( $('.oldActive').is(':last-child')) {
        $('.sp').first().addClass('active');
        }
        else{
        $('.oldActive').next().addClass('active');
        }
    $('.oldActive').removeClass('oldActive');
    $('.sp').fadeOut();
    $('.active').fadeIn();


    });

       $('#button-previous').click(function(){
    $('.active').removeClass('active').addClass('oldActive');    
           if ( $('.oldActive').is(':first-child')) {
        $('.sp').last().addClass('active');
        }
           else{
    $('.oldActive').prev().addClass('active');
           }
    $('.oldActive').removeClass('oldActive');
    $('.sp').fadeOut();
    $('.active').fadeIn();
    });




});

So now the explanation.
Stage 1
1) Load the script on document ready.

2) Grab the first slide and add a class 'active' to it so we know which slide we are dealing with.

3) Hide all slides and show active slide. So now slide #1 is display block and all the rest are display:none;

Stage 2 Working with the button-next click event.
1) Remove the current active class from the slide that will be disappearing and give it the class oldActive so we know that it is on it's way out.

2) Next is an if statement to check if we are at the end of the slideshow and need to return to the start again. It checks if oldActive (i.e. the outgoing slide) is the last child. If it is, then go back to the first child and make it 'active'. If it's not the last child, then just grab the next element (using .next() ) and give it class active.

3) We remove the class oldActive because it's no longer needed.

4) fadeOut all of the slides

5) fade In the active slides

Step 3

Same as in step two but using some reverse logic for traversing through the elements backwards.

It's important to note there are thousands of ways you can achieve this. This is merely my take on the situation.

Entity Framework and SQL Server View

If you do not want to mess with what should be the primary key, I recommend:

  1. Incorporate ROW_NUMBER into your selection
  2. Set it as primary key
  3. Set all other columns/members as non-primary in the model

CSS: Auto resize div to fit container width

#wrapper
{
    min-width:960px;
    margin-left:auto;
    margin-right:auto;
    position-relative;
}
#left
{
    width:200px;
    position: absolute;
    background-color:antiquewhite;
    margin-left:10px;
    z-index: 2;
}
#content
{
    padding-left:210px;
    width:100%;
    background-color:AppWorkspace;
    position: relative;
    z-index: 1;
}

If you need the whitespace on the right of #left, then add a border-right: 10px solid #FFF; to #left and add 10px to the padding-left in #content

Base64 encoding and decoding in oracle

All the previous posts are correct. There's more than one way to skin a cat. Here is another way to do the same thing: (just replace "what_ever_you_want_to_convert" with your string and run it in Oracle:

    set serveroutput on;
    DECLARE
    v_str VARCHAR2(1000);
    BEGIN
    --Create encoded value
    v_str := utl_encode.text_encode
    ('what_ever_you_want_to_convert','WE8ISO8859P1', UTL_ENCODE.BASE64);
    dbms_output.put_line(v_str);
    --Decode the value..
    v_str := utl_encode.text_decode
    (v_str,'WE8ISO8859P1', UTL_ENCODE.BASE64);
    dbms_output.put_line(v_str);
    END;
    /

source

How can I change a file's encoding with vim?

Just like your steps, setting fileencoding should work. However, I'd like to add one "set bomb" to help editor consider the file as UTF8.

$ vim file
:set bomb
:set fileencoding=utf-8
:wq

Appending values to dictionary in Python

Just use append:

list1 = [1, 2, 3, 4, 5]
list2 = [123, 234, 456]
d = {'a': [], 'b': []}
d['a'].append(list1)
d['a'].append(list2)
print d['a']

TypeError: Object of type 'bytes' is not JSON serializable

I guess the answer you need is referenced here Python sets are not json serializable

Not all datatypes can be json serialized . I guess pickle module will serve your purpose.

Export Postgresql table data using pgAdmin

Just right click on a table and select "backup". The popup will show various options, including "Format", select "plain" and you get plain SQL.

pgAdmin is just using pg_dump to create the dump, also when you want plain SQL.

It uses something like this:

pg_dump --user user --password --format=plain --table=tablename --inserts --attribute-inserts etc.

MySQLi count(*) always returns 1

You have to fetch that one record, it will contain the result of Count()

$result = $db->query("SELECT COUNT(*) FROM `table`");
$row = $result->fetch_row();
echo '#: ', $row[0];

Perform a Shapiro-Wilk Normality Test

Set the data as a vector and then place in the function.

iOS Remote Debugging

Adobe Edge Inspect (https://creative.adobe.com/products/inspect) is another way to debug all your mobile devices IOS and Android (no Windows Phone though). It uses weinre for remote DOM inspection/changing. It's not the fastest of methods, but it works on Windows.

in linux terminal, how do I show the folder's last modification date, taking its content into consideration?

If I could, I would vote for the answer by Paulo. I tested it and understood the concept. I can confirm it works. The find command can output many parameters. For example, add the following to the --printf clause:

%a for attributes in the octal format
%n for the file name including a complete path

Example:

find Desktop/ -exec stat \{} --printf="%y %n\n" \; | sort -n -r | head -1
2011-02-14 22:57:39.000000000 +0100 Desktop/new file

Let me raise this question as well: Does the author of this question want to solve his problem using Bash or PHP? That should be specified.

How to use gitignore command in git

So based on what you said, these files are libraries/documentation you don't want to delete but also don't want to push to github. Let say you have your project in folder your_project and a doc directory: your_project/doc.

  1. Remove it from the project directory (without actually deleting it): git rm --cached doc/*
  2. If you don't already have a .gitignore, you can make one right inside of your project folder: project/.gitignore.
  3. Put doc/* in the .gitignore
  4. Stage the file to commit: git add project/.gitignore
  5. Commit: git commit -m "message".
  6. Push your change to github.

WCF Exception: Could not find a base address that matches scheme http for the endpoint

My issue was also caused by missing https binding in IIS: Selected default website > On the far right pane selected Bindings > add > https

Choose 'IIS Express Development Certificate' and set port to 443

Android Studio - UNEXPECTED TOP-LEVEL EXCEPTION:

I solved my problem with adding these in build gradle:

   defaultConfig {
   multiDexEnabled true


 dependencies {
 compile 'com.android.support:multidex:1.0.0'

another solution can be removing unnecessary libraries

How to merge two arrays in JavaScript and de-duplicate items

Here is my solution https://gist.github.com/4692150 with deep equals and easy to use result:

function merge_arrays(arr1,arr2)
{
   ... 
   return {first:firstPart,common:commonString,second:secondPart,full:finalString}; 
}

console.log(merge_arrays(
[
[1,"10:55"] ,
[2,"10:55"] ,
[3,"10:55"]
],[
[3,"10:55"] ,
[4,"10:55"] ,
[5,"10:55"]
]).second);

result:
[
[4,"10:55"] ,
[5,"10:55"]
]

Error: Generic Array Creation

You can't create arrays with a generic component type.

Create an array of an explicit type, like Object[], instead. You can then cast this to PCB[] if you want, but I don't recommend it in most cases.

PCB[] res = (PCB[]) new Object[list.size()]; /* Not type-safe. */

If you want type safety, use a collection like java.util.List<PCB> instead of an array.

By the way, if list is already a java.util.List, you should use one of its toArray() methods, instead of duplicating them in your code. This doesn't get your around the type-safety problem though.

Change hover color on a button with Bootstrap customization

or can do this...
set all btn ( class name like : .btn- + $theme-colors: map-merge ) styles at one time :

@each $color, $value in $theme-colors {
  .btn-#{$color} {
    @include button-variant($value, $value,
    // modify
    $hover-background: lighten($value, 7.5%),
    $hover-border: lighten($value, 10%),
    $active-background: lighten($value, 10%),
    $active-border: lighten($value, 12.5%)
    // /modify
    );
  }
}

// code from "node_modules/bootstrap/scss/_buttons.scss"

should add into your customization scss file.

Editing specific line in text file in Python

def replace_line(file_name, line_num, text):
    lines = open(file_name, 'r').readlines()
    lines[line_num] = text
    out = open(file_name, 'w')
    out.writelines(lines)
    out.close()

And then:

replace_line('stats.txt', 0, 'Mage')

Why do people say that Ruby is slow?

Why is Ruby considered slow?

Because if you run typical benchmarks between Ruby and other languages, Ruby loses.

I do not find Ruby to be slow but then again, I'm just using it to make simple CRUD apps and company blogs. What sort of projects would I need to be doing before I find Ruby becoming slow? Or is this slowness just something that affects all programming languages?

Ruby probably wouldn't serve you well in writing a real-time digital signal processing application, or any kind of real-time control system. Ruby (with today's VMs) would probably choke on a resource-constrained computer such as smartphones.

Remember that a lot of the processing on your web applications is actually done by software developed in C. e.g. Apache, Thin, Nginx, SQLite, MySQL, PostgreSQL, many parsing libraries, RMagick, TCP/IP, etc are C programs used by Ruby. Ruby provides the glue and the business logic.

What are your options as a Ruby programmer if you want to deal with this "slowness"?

Switch to a faster language. But that carries a cost. It is a cost that may be worth it. But for most web applications, language choice is not a relevant factor because there is just not enough traffic justify using a faster language that costs much more to develop for.

Which version of Ruby would best suit an application like Stack Overflow where speed is critical and traffic is intense?

Other folks have answered this - JRuby, IronRuby, REE will make the Ruby part of your application run faster on platforms that can afford the VMs. And since it is often not Ruby that causes slowness, but your computer system architecture and application architecture, you can do stuff like database replication, multiple application servers, loadbalancing with reverse proxies, HTTP caching, memcache, Ajax, client-side caching, etc. None of this stuff is Ruby.

Finally, I can't find much news on Ruby 2.0 - I take it we're a good few years away from that then?

Most folks are waiting for Ruby 1.9.1. I myself am waiting for Rails 3.1 on Ruby 1.9.1 on JRuby.

Finally, please remember that a lot of developers choose Ruby because it makes programming a more joyful experience compared to other languages, and because Ruby with Rails enables skilled web developers to develop applications very quickly.

org.hibernate.MappingException: Could not determine type for: java.util.Set

Adding the @ElementCollection to the List field solved this issue:

@Column
@ElementCollection(targetClass=Integer.class)
private List<Integer> countries;

What is a "callback" in C and how are they implemented?

Usually this can be done by using a function pointer, that is a special variable that points to the memory location of a function. You can then use this to call the function with specific arguments. So there will probably be a function that sets the callback function. This will accept a function pointer and then store that address somewhere where it can be used. After that when the specified event is triggered, it will call that function.

What does `set -x` do?

-u: disabled by default. When activated, an error message is displayed when using an unconfigured variable.

-v: inactive by default. After activation, the original content of the information will be displayed (without variable resolution) before the information is output.

-x: inactive by default. If activated, the command content will be displayed before the command is run (after variable resolution, there is a ++ symbol).

Compare the following differences:

/ # set -v && echo $HOME
/root
/ # set +v && echo $HOME
set +v && echo $HOME
/root

/ # set -x && echo $HOME
+ echo /root
/root
/ # set +x && echo $HOME
+ set +x
/root

/ # set -u && echo $NOSET
/bin/sh: NOSET: parameter not set
/ # set +u && echo $NOSET

oracle varchar to number

Since the column is of type VARCHAR, you should convert the input parameter to a string rather than converting the column value to a number:

select * from exception where exception_value = to_char(105);

imagecreatefromjpeg and similar functions are not working in PHP

After installing php5-gd apache restart is needed.

Reporting Services permissions on SQL Server R2 SSRS

In my case after running IE as an administrator, i had to add the url of the report manager to the Local Internet Zones in Internet Explorer, not Trusted Sites.

How to get old Value with onchange() event in text box

You can do this: add oldvalue attribute to html element, add set oldvalue when user click. Then onchange event use oldvalue.

<input type="text" id="test" value ="ABS" onchange="onChangeTest(this)" onclick="setoldvalue(this)" oldvalue="">

<script>
function setoldvalue(element){
   element.setAttribute("oldvalue",this.value);
}

function onChangeTest(element){
   element.setAttribute("value",this.getAttribute("oldvalue"));
}
</script>

How do I execute a Shell built-in command with a C function?

If you just want to execute the shell command in your c program, you could use,

   #include <stdlib.h>

   int system(const char *command);

In your case,

system("pwd");

The issue is that there isn't an executable file called "pwd" and I'm unable to execute "echo $PWD", since echo is also a built-in command with no executable to be found.

What do you mean by this? You should be able to find the mentioned packages in /bin/

sudo find / -executable -name pwd
sudo find / -executable -name echo

Set a thin border using .css() in javascript

After a few futile hours battling with a 'SyntaxError: missing : after property id' message I can now expand on this topic:

border-width is a valid css property but it is not included in the jQuery css oject definition, so .css({border-width: '2px'}) will cause an error, but it's quite happy with .css({'border-width': '2px'}), presumably property names in quotes are just passed on as received.

How to properly override clone method?

Just because java's implementation of Cloneable is broken it doesn't mean you can't create one of your own.

If OP real purpose was to create a deep clone, i think that it is possible to create an interface like this:

public interface Cloneable<T> {
    public T getClone();
}

then use the prototype constructor mentioned before to implement it:

public class AClass implements Cloneable<AClass> {
    private int value;
    public AClass(int value) {
        this.vaue = value;
    }

    protected AClass(AClass p) {
        this(p.getValue());
    }

    public int getValue() {
        return value;
    }

    public AClass getClone() {
         return new AClass(this);
    }
}

and another class with an AClass object field:

public class BClass implements Cloneable<BClass> {
    private int value;
    private AClass a;

    public BClass(int value, AClass a) {
         this.value = value;
         this.a = a;
    }

    protected BClass(BClass p) {
        this(p.getValue(), p.getA().getClone());
    }

    public int getValue() {
        return value;
    }

    public AClass getA() {
        return a;
    }

    public BClass getClone() {
         return new BClass(this);
    }
}

In this way you can easely deep clone an object of class BClass without need for @SuppressWarnings or other gimmicky code.

Getting a list of all subdirectories in the current directory

Implemented this using python-os-walk. (http://www.pythonforbeginners.com/code-snippets-source-code/python-os-walk/)

import os

print("root prints out directories only from what you specified")
print("dirs prints out sub-directories from root")
print("files prints out all files from root and directories")
print("*" * 20)

for root, dirs, files in os.walk("/var/log"):
    print(root)
    print(dirs)
    print(files)

Git copy changes from one branch to another

If you are using tortoise git.

please follow the below steps.

  1. Checkout BranchB
  2. Open project folder, go to TortoiseGit --> Pull
  3. In pull screen, Change the remote branch "BranchA" and click ok.
  4. Then right click again, go to TortoiseGit --> Push.

Now your changes moved from BranchA to BranchB

Align image to left of text on same line - Twitter Bootstrap3

You can use floating:

<div class="paragraphs">
  <div class="row">
    <div class="span4">
      <img style="float:left" src="../site/img/success32.png"/>
      <div class="content-heading"><h3>Experience &nbsp </h3></div>
      <p style="clear:both">Donec id elit non mi porta gravida at eget metus. Etiam porta sem malesuada magna mollis euismod. Donec sed odio dui.</p>
    </div>
  </div>
</div>

If you want the following <p> to stay at the same line too, remove its

style="clear:both"

but then you should add

<div style="clear:both"></div>

after it.

How to embed a video into GitHub README.md?

just to extend @GabLeRoux's answer:

[<img src="https://img.youtube.com/vi/<VIDEO ID>/maxresdefault.jpg" width="50%">](https://youtu.be/<VIDEO ID>)

this way you will be able to adjust the size of the thumbnail image in the README.md file on you Github repo.

PHP 7 RC3: How to install missing MySQL PDO

If you are on windows, and your php folder is not in your PATH, you have set the absolute directory in your php.ini

for example:

extension_dir = "C:/php7/ext"

and uncomment

extension=php_mysqli.dll
extension=php_pdo_mysql.dll

Restart apache2.4 and it should work.

I hope it helps.

Get Element value with minidom with Python

I had a similar case, what worked for me was:

name.firstChild.childNodes[0].data

XML is supposed to be simple and it really is and I don't know why python's minidom did it so complicated... but it's how it's made

How to use the 'og' (Open Graph) meta tag for Facebook share

I built a tool for meta generation. It pre-configures entries for Facebook, Google+ and Twitter, and you can use it free here: http://www.groovymeta.com

To answer the question a bit more, OG tags (Open Graph) tags work similarly to meta tags, and should be placed in the HEAD section of your HTML file. See Facebook's best practises for more information on how to use OG tags effectively.

What is the best IDE for C Development / Why use Emacs over an IDE?

I've moved from a terminal text-editor+make environment to Eclipse for most of my projects. Spanning from C and C++, to Java and Python to name few languages I am currently working with.

The reason was simply productivity. I could not afford spending time and effort on keeping all projects "in my head" as other things got more important.

There are benefits of using the "hardcore" approach (terminal) - such as that you have a much thinner layer between yourself and the code which allows you to be a bit more productive when you're all "inside" the project and everything is on the top of your head. But I don't think it is possible to defend that way of working just for it's own sake when your mind is needed elsewhere.

Usually when you work with command line tools you will frequently have to solve a lot of boilerplate problems that will keep you from being productive. You will need to know the tools in detail to fully leverage their potentials. Also maintaining a project will take a lot more effort. Refactoring will lead to updates in make-files, etc.

To summarize: If you only work on one or two projects, preferably full-time without too much distractions, "terminal based coding" can be more productive than a full blown IDE. However, if you need to spend your thinking energy on something more important an IDE is definitely the way to go in order to keep productivity.

Make your choice accordingly.

Number of times a particular character appears in a string

You may do this completely in-line by replacing the desired character with an empty string, calling LENGTH function and substracting from the original string's length.

SELECT 
  CustomerName, 
  LENGTH(CustomerName) -
  LENGTH(REPLACE(CustomerName, ' ', '')) AS NumberOfSpaces
FROM Customers;

how to implement Pagination in reactJs

A ReactJS dumb component to render pagination. You can also use this Library:

https://www.npmjs.com/package/react-js-pagination

Some Examples are Here:

http://vayser.github.io/react-js-pagination/

OR

You can also Use this https://codepen.io/PiotrBerebecki/pen/pEYPbY

failed to push some refs to [email protected]

Also, make sure your branch is clean and there is nothing unstaged you can check with git status stash or commit the changes then run the comand

javascript - Create Simple Dynamic Array

updated = > june 2020

if are you using node js you can create or append a string value with " ," operator then inside the loop you can

for (var j = 0; j <= data.legth -1; j++) {
                    lang += data.lang  +", " ;

                }

 var langs = lang.split(',')
 console.log("Languages =>",  lang, typeof(lang), typeof(langs), langs) 
 console.log(lang[0]) // here access arrary by index value
            

you can see the type of string and object

Vba macro to copy row from table if value in table meets condition

you are describing a Problem, which I would try to solve with the VLOOKUP function rather than using VBA.

You should always consider a non-vba solution first.

Here are some application examples of VLOOKUP (or SVERWEIS in German, as i know it):

http://www.youtube.com/watch?v=RCLUM0UMLXo

http://office.microsoft.com/en-us/excel-help/vlookup-HP005209335.aspx


If you have to make it as a macro, you could use VLOOKUP as an application function - a quick solution with slow performance - or you will have to make a simillar function yourself.

If it has to be the latter, then there is need for more details on your specification, regarding performance questions.

You could copy any range to an array, loop through this array and check for your value, then copy this value to any other range. This is how i would solve this as a vba-function.

This would look something like that:

Public Sub CopyFilter()

  Dim wks As Worksheet
  Dim avarTemp() As Variant
  'go through each worksheet
  For Each wks In ThisWorkbook.Worksheets
        avarTemp = wks.UsedRange
        For i = LBound(avarTemp, 1) To UBound(avarTemp, 1)
          'check in the first column in each row
          If avarTemp(i, LBound(avarTemp, 2)) = "XYZ" Then
            'copy cell
             targetWks.Cells(1, 1) = avarTemp(i, LBound(avarTemp, 2))
          End If
        Next i
  Next wks
End Sub

Ok, now i have something nice which could come in handy for myself:

Public Function FILTER(ByRef rng As Range, ByRef lngIndex As Long) As Variant
  Dim avarTemp() As Variant
  Dim avarResult() As Variant
  Dim i As Long
  avarTemp = rng

  ReDim avarResult(0)

  For i = LBound(avarTemp, 1) To UBound(avarTemp, 1)
      If avarTemp(i, 1) = "active" Then
        avarResult(UBound(avarResult)) = avarTemp(i, lngIndex)
        'expand our result array
        ReDim Preserve avarResult(UBound(avarResult) + 1)
      End If
  Next i

  FILTER = avarResult
End Function

You can use it in your Worksheet like this =FILTER(Tabelle1!A:C;2) or with =INDEX(FILTER(Tabelle1!A:C;2);3) to specify the result row. I am sure someone could extend this to include the index functionality into FILTER or knows how to return a range like object - maybe I could too, but not today ;)

How to annotate MYSQL autoincrement field with JPA annotations

Using MySQL, only this approach was working for me:

@Id @GeneratedValue(strategy=GenerationType.IDENTITY)
private Long id;

The other 2 approaches stated by Pascal in his answer were not working for me.

Is there a concise way to iterate over a stream with indices in Java 8?

The cleanest way is to start from a stream of indices:

String[] names = {"Sam", "Pamela", "Dave", "Pascal", "Erik"};
IntStream.range(0, names.length)
         .filter(i -> names[i].length() <= i)
         .mapToObj(i -> names[i])
         .collect(Collectors.toList());

The resulting list contains "Erik" only.


One alternative which looks more familiar when you are used to for loops would be to maintain an ad hoc counter using a mutable object, for example an AtomicInteger:

String[] names = {"Sam", "Pamela", "Dave", "Pascal", "Erik"};
AtomicInteger index = new AtomicInteger();
List<String> list = Arrays.stream(names)
                          .filter(n -> n.length() <= index.incrementAndGet())
                          .collect(Collectors.toList());

Note that using the latter method on a parallel stream could break as the items would not necesarily be processed "in order".

Copying formula to the next row when inserting a new row

One other key thing that I found regarding copying rows within a table, is that the worksheet you are working on needs to be activated. If you have a workbook with multiple sheets, you need to save the sheet you called the macro from, and then activate the sheet with the table. Once you are done, you can re-activate the original sheet.

You can use Application.ScreenUpdating = False to make sure the user doesn't see that you are switching worksheets within your macro.

If you don't have the worksheet activated, the copy doesn't seem to work properly, i.e. some stuff seem to work, and other stuff doesn't ??

MySQL Check if username and password matches in Database

Instead of selecting all the columns in count count(*) you can limit count for one column count(UserName).

You can limit the whole search to one row by using Limit 0,1

SELECT COUNT(UserName)
  FROM TableName
 WHERE UserName = 'User' AND
       Password = 'Pass'
 LIMIT 0, 1

curl: (6) Could not resolve host: application

I was getting this error too. I resolved it by installing: https://git-scm.com/

and running the command from the Git Bash window.

Display a loading bar before the entire page is loaded

Whenever you try to load any data in this window this gif will load.

HTML

Make a Div

<div class="loader"></div>

CSS .

.loader {
    position: fixed;
    left: 0px;
    top: 0px;
    width: 100%;
    height: 100%;
    z-index: 9999;
    background: url('https://lkp.dispendik.surabaya.go.id/assets/loading.gif') 50% 50% no-repeat rgb(249,249,249);

jQuery

$(window).load(function() {
        $(".loader").fadeOut("slow");
});
<script src="https://code.jquery.com/jquery-1.9.1.min.js"></script>

enter image description here

Subset of rows containing NA (missing) values in a chosen column of a data frame

NA is a special value in R, do not mix up the NA value with the "NA" string. Depending on the way the data was imported, your "NA" and "NULL" cells may be of various type (the default behavior is to convert "NA" strings to NA values, and let "NULL" strings as is).

If using read.table() or read.csv(), you should consider the "na.strings" argument to do clean data import, and always work with real R NA values.

An example, working in both cases "NULL" and "NA" cells :

DF <- read.csv("file.csv", na.strings=c("NA", "NULL"))
new_DF <- subset(DF, is.na(DF$Var2))

how to put image in a bundle and pass it to another activity

So you can do it like this, but the limitation with the Parcelables is that the payload between activities has to be less than 1MB total. It's usually better to save the Bitmap to a file and pass the URI to the image to the next activity.

 protected void onCreate(Bundle savedInstanceState) {     setContentView(R.layout.my_layout);     Bitmap bitmap = getIntent().getParcelableExtra("image");     ImageView imageView = (ImageView) findViewById(R.id.imageview);     imageView.setImageBitmap(bitmap);  } 

Java 8 lambdas, Function.identity() or t->t

From the JDK source:

static <T> Function<T, T> identity() {
    return t -> t;
}

So, no, as long as it is syntactically correct.

Align two divs horizontally side by side center to the page using bootstrap css

Alternative which I did programming Angular:

    <div class="form-row">
        <div class="form-group col-md-7">
             Left
        </div>
        <div class="form-group col-md-5">
             Right
        </div>
    </div>

How to ignore user's time zone and force Date() use specific time zone

I have a suspicion, that the Answer doesn't give the correct result. In the question the asker wants to convert timestamp from server to current time in Hellsinki disregarding current time zone of the user.

It's the fact that the user's timezone can be what ever so we cannot trust to it.

If eg. timestamp is 1270544790922 and we have a function:

var _date = new Date();
_date.setTime(1270544790922);
var _helsenkiOffset = 2*60*60;//maybe 3
var _userOffset = _date.getTimezoneOffset()*60*60; 
var _helsenkiTime = new Date(_date.getTime()+_helsenkiOffset+_userOffset);

When a New Yorker visits the page, alert(_helsenkiTime) prints:

Tue Apr 06 2010 05:21:02 GMT-0400 (EDT)

And when a Finlander visits the page, alert(_helsenkiTime) prints:

Tue Apr 06 2010 11:55:50 GMT+0300 (EEST)

So the function is correct only if the page visitor has the target timezone (Europe/Helsinki) in his computer, but fails in nearly every other part of the world. And because the server timestamp is usually UNIX timestamp, which is by definition in UTC, the number of seconds since the Unix Epoch (January 1 1970 00:00:00 GMT), we cannot determine DST or non-DST from timestamp.

So the solution is to DISREGARD the current time zone of the user and implement some way to calculate UTC offset whether the date is in DST or not. Javascript has not native method to determine DST transition history of other timezone than the current timezone of user. We can achieve this most simply using server side script, because we have easy access to server's timezone database with the whole transition history of all timezones.

But if you have no access to the server's (or any other server's) timezone database AND the timestamp is in UTC, you can get the similar functionality by hard coding the DST rules in Javascript.

To cover dates in years 1998 - 2099 in Europe/Helsinki you can use the following function (jsfiddled):

function timestampToHellsinki(server_timestamp) {
    function pad(num) {
        num = num.toString();
        if (num.length == 1) return "0" + num;
        return num;
    }

    var _date = new Date();
    _date.setTime(server_timestamp);

    var _year = _date.getUTCFullYear();

    // Return false, if DST rules have been different than nowadays:
    if (_year<=1998 && _year>2099) return false;

    // Calculate DST start day, it is the last sunday of March
    var start_day = (31 - ((((5 * _year) / 4) + 4) % 7));
    var SUMMER_start = new Date(Date.UTC(_year, 2, start_day, 1, 0, 0));

    // Calculate DST end day, it is the last sunday of October
    var end_day = (31 - ((((5 * _year) / 4) + 1) % 7))
    var SUMMER_end = new Date(Date.UTC(_year, 9, end_day, 1, 0, 0));

    // Check if the time is between SUMMER_start and SUMMER_end
    // If the time is in summer, the offset is 2 hours
    // else offset is 3 hours
    var hellsinkiOffset = 2 * 60 * 60 * 1000;
    if (_date > SUMMER_start && _date < SUMMER_end) hellsinkiOffset = 
    3 * 60 * 60 * 1000;

    // Add server timestamp to midnight January 1, 1970
    // Add Hellsinki offset to that
    _date.setTime(server_timestamp + hellsinkiOffset);
    var hellsinkiTime = pad(_date.getUTCDate()) + "." + 
    pad(_date.getUTCMonth()) + "." + _date.getUTCFullYear() + 
    " " + pad(_date.getUTCHours()) + ":" +
    pad(_date.getUTCMinutes()) + ":" + pad(_date.getUTCSeconds());

    return hellsinkiTime;
}

Examples of usage:

var server_timestamp = 1270544790922;
document.getElementById("time").innerHTML = "The timestamp " + 
server_timestamp + " is in Hellsinki " + 
timestampToHellsinki(server_timestamp);

server_timestamp = 1349841923 * 1000;
document.getElementById("time").innerHTML += "<br><br>The timestamp " + 
server_timestamp + " is in Hellsinki " + timestampToHellsinki(server_timestamp);

var now = new Date();
server_timestamp = now.getTime();
document.getElementById("time").innerHTML += "<br><br>The timestamp is now " +
server_timestamp + " and the current local time in Hellsinki is " +
timestampToHellsinki(server_timestamp);?

And this print the following regardless of user timezone:

The timestamp 1270544790922 is in Hellsinki 06.03.2010 12:06:30

The timestamp 1349841923000 is in Hellsinki 10.09.2012 07:05:23

The timestamp is now 1349853751034 and the current local time in Hellsinki is 10.09.2012 10:22:31

Of course if you can return timestamp in a form that the offset (DST or non-DST one) is already added to timestamp on server, you don't have to calculate it clientside and you can simplify the function a lot. BUT remember to NOT use timezoneOffset(), because then you have to deal with user timezone and this is not the wanted behaviour.

How to center cards in bootstrap 4?

Put the elements which you want to shift to the centre within this div tag.

<div class="col d-flex justify-content-center">
</div>

Editor does not contain a main type in Eclipse

Ideally, the source code file should go within the src/default package even if you haven't provided any package name. For some reason, the source file might be outside src folder. Create within the scr folder it will work!

Is there a RegExp.escape function in JavaScript?

There has only ever been and ever will be 12 meta characters that need to be escaped to be considered a literal.

It doesn't matter what is done with the escaped string, inserted into a balanced regex wrapper or appended. It doesn't matter.

Do a string replace using this

var escaped_string = oldstring.replace(/[\\^$.|?*+()[{]/g, '\\$&');

Retrieve Button value with jQuery

Button does not have a value attribute. To get the text of button try:

$('.my_button').click(function() {
     alert($(this).html());
});

Way to create multiline comments in Bash?

Here's how I do multiline comments in bash.

This mechanism has two advantages that I appreciate. One is that comments can be nested. The other is that blocks can be enabled by simply commenting out the initiating line.

#!/bin/bash
# : <<'####.block.A'
echo "foo {" 1>&2
fn data1
echo "foo }" 1>&2
: <<'####.block.B'
fn data2 || exit
exit 1
####.block.B
echo "can't happen" 1>&2
####.block.A

In the example above the "B" block is commented out, but the parts of the "A" block that are not the "B" block are not commented out.

Running that example will produce this output:

foo {
./example: line 5: fn: command not found
foo }
can't happen

How I can check if an object is null in ruby on rails 2?

You can use the simple not flag to validate that. Example

if !@objectname

This will return true if @objectname is nil. You should not use dot operator or a nil value, else it will throw

*** NoMethodError Exception: undefined method `isNil?' for nil:NilClass

An ideal nil check would be like:

!@objectname || @objectname.nil? || @objectname.empty?

CSS '>' selector; what is it?

It means parent/child

example:

html>body

that's saying that body is a child of html

Check out: Selectors

Where is Xcode's build folder?

enter image description here

enter image description here

Configure XCode project settings, it can solve your problem.

Identifying country by IP address

Yes, countries have specific IP address ranges as you mentioned.

For example, Australia is between 16777216 - 16777471. China is between 16777472 - 16778239. But one country may have multiple ranges. For example, Australia also has this range between 16778240 - 16779263

(These are numerical conversions of IP addresses. It depends whether you use IPv4 or IPv6)

More information about these ranges can be seen here: http://software77.net/cidr-101.html

We get the ip addresses of our website visitors and sometimes want to make relevant campaign for a specific country. We were using bulk conversion tools but later on decided to define the rules in an Excel file and convert it in the tool. And we have built this Excel template: https://www.someka.net/excel-template/ip-to-country-converter/

Now we use this for our own needs and also sell it. I don't want it to be a sales pitch but for those who are looking for an easy solution can benefit from this.

How to remove numbers from string using Regex.Replace?

You can do it with a LINQ like solution instead of a regular expression:

string input = "123- abcd33";
string chars = new String(input.Where(c => c != '-' && (c < '0' || c > '9')).ToArray());

A quick performance test shows that this is about five times faster than using a regular expression.

How to use java.Set

The first thing you need to study is the java.util.Set API.

Here's a small example of how to use its methods:

    Set<Integer> numbers = new TreeSet<Integer>();

    numbers.add(2);
    numbers.add(5);

    System.out.println(numbers); // "[2, 5]"
    System.out.println(numbers.contains(7)); // "false"

    System.out.println(numbers.add(5)); // "false"
    System.out.println(numbers.size()); // "2"

    int sum = 0;
    for (int n : numbers) {
        sum += n;
    }
    System.out.println("Sum = " + sum); // "Sum = 7"

    numbers.addAll(Arrays.asList(1,2,3,4,5));
    System.out.println(numbers); // "[1, 2, 3, 4, 5]"

    numbers.removeAll(Arrays.asList(4,5,6,7));
    System.out.println(numbers); // "[1, 2, 3]"

    numbers.retainAll(Arrays.asList(2,3,4,5));
    System.out.println(numbers); // "[2, 3]"

Once you're familiar with the API, you can use it to contain more interesting objects. If you haven't familiarized yourself with the equals and hashCode contract, already, now is a good time to start.

In a nutshell:

  • @Override both or none; never just one. (very important, because it must satisfied property: a.equals(b) == true --> a.hashCode() == b.hashCode()
    • Be careful with writing boolean equals(Thing other) instead; this is not a proper @Override.
  • For non-null references x, y, z, equals must be:
    • reflexive: x.equals(x).
    • symmetric: x.equals(y) if and only if y.equals(x)
    • transitive: if x.equals(y) && y.equals(z), then x.equals(z)
    • consistent: x.equals(y) must not change unless the objects have mutated
    • x.equals(null) == false
  • The general contract for hashCode is:
    • consistent: return the same number unless mutation happened
    • consistent with equals: if x.equals(y), then x.hashCode() == y.hashCode()
      • strictly speaking, object inequality does not require hash code inequality
      • but hash code inequality necessarily requires object inequality
  • What counts as mutation should be consistent between equals and hashCode.

Next, you may want to impose an ordering of your objects. You can do this by making your type implements Comparable, or by providing a separate Comparator.

Having either makes it easy to sort your objects (Arrays.sort, Collections.sort(List)). It also allows you to use SortedSet, such as TreeSet.


Further readings on stackoverflow:

How do I use CREATE OR REPLACE?

If this is for MS SQL.. The following code will always run no matter what if the table exist already or not.

if object_id('mytablename') is not null //has the table been created already in the db
Begin
     drop table mytablename
End

Create table mytablename (...

Is there an easy way to attach source in Eclipse?

Just click on attach source and select folder path ... name will be same as folder name (in my case). Remember one thing you need to select path upto project folder base location with "\" at suffix ex D:\MyProject\

How to get the changes on a branch in Git

In the context of a revision list, A...B is how git-rev-parse defines it. git-log takes a revision list. git-diff does not take a list of revisions - it takes one or two revisions, and has defined the A...B syntax to mean how it's defined in the git-diff manpage. If git-diff did not explicitly define A...B, then that syntax would be invalid. Note that the git-rev-parse manpage describes A...B in the "Specifying Ranges" section, and everything in that section is only valid in situations where a revision range is valid (i.e. when a revision list is desired).

To get a log containing just x, y, and z, try git log HEAD..branch (two dots, not three). This is identical to git log branch --not HEAD, and means all commits on branch that aren't on HEAD.

How to save a figure in MATLAB from the command line?

Use saveas:

h=figure;
plot(x,y,'-bs','Linewidth',1.4,'Markersize',10);
% ...
saveas(h,name,'fig')
saveas(h,name,'jpg')

This way, the figure is plotted, and automatically saved to '.jpg' and '.fig'. You don't need to wait for the plot to appear and click 'save as' in the menu. Way to go if you need to plot/save a lot of figures.

If you really do not want to let the plot appear (it has to be loaded anyway, can't avoid that, else there is also nothing to save), you can hide it:

h=figure('visible','off')

JavaScript alert box with timer

If you are looking for an alert that dissapears after an interval you could try the jQuery UI Dialog widget.

resource error in android studio after update: No Resource Found

in your projects build.gradle file... write as below.. i have solved that error by change the appcompat version from v7.23.0.0 to v7.22.2.1..

dependencies

{

compile fileTree(dir: 'libs', include: ['*.jar'])
compile 'com.android.support:appcompat-v7:22.2.1'

}

Below screen shot is for better understanding.

Types in Objective-C on iOS

Update for the new 64bit arch

Ranges:
CHAR_MIN:   -128
CHAR_MAX:   127
SHRT_MIN:   -32768
SHRT_MAX:   32767
INT_MIN:    -2147483648
INT_MAX:    2147483647
LONG_MIN:   -9223372036854775808
LONG_MAX:   9223372036854775807
ULONG_MAX:  18446744073709551615
LLONG_MIN:  -9223372036854775808
LLONG_MAX:  9223372036854775807
ULLONG_MAX: 18446744073709551615

Work with a time span in Javascript

a simple timestamp formatter in pure JS with custom patterns support and locale-aware, using Intl.RelativeTimeFormat

some formatting examples

/** delta: 1234567890, @locale: 'en-US', @style: 'long' */

/* D~ h~ m~ s~ */
14 days 6 hours 56 minutes 7 seconds

/* D~ h~ m~ s~ f~ */
14 days 6 hours 56 minutes 7 seconds 890

/* D#"d" h#"h" m#"m" s#"s" f#"ms" */
14d 6h 56m 7s 890ms

/* D,h:m:s.f */
14,06:56:07.890

/* D~, h:m:s.f */
14 days, 06:56:07.890

/* h~ m~ s~ */
342 hours 56 minutes 7 seconds

/* s~ m~ h~ D~ */
7 seconds 56 minutes 6 hours 14 days

/* up D~, h:m */
up 14 days, 06:56

the code & test

_x000D_
_x000D_
/**
    Init locale formatter:
    
        timespan.locale(@locale, @style)
    
    Example:

        timespan.locale('en-US', 'long');
        timespan.locale('es', 'narrow');

    Format time delta:
    
        timespan.format(@pattern, @milliseconds)

        @pattern tokens:
            D: days, h: hours, m: minutes, s: seconds, f: millis

        @pattern token extension:
            h  => '0'-padded value, 
            h# => raw value,
            h~ => locale formatted value

    Example:

        timespan.format('D~ h~ m~ s~ f "millis"', 1234567890);
        
        output: 14 days 6 hours 56 minutes 7 seconds 890 millis

    NOTES:

    * milliseconds unit have no locale translation
    * may encounter declension issues for some locales
    * use quoted text for raw inserts
            
*/

const timespan = (() => {
    let rtf, tokensRtf;
    const
    tokens = /[Dhmsf][#~]?|"[^"]*"|'[^']*'/g,
    map = [
        {t: [['D', 1], ['D#'], ['D~', 'day']], u: 86400000},
        {t: [['h', 2], ['h#'], ['h~', 'hour']], u: 3600000},
        {t: [['m', 2], ['m#'], ['m~', 'minute']], u: 60000},
        {t: [['s', 2], ['s#'], ['s~', 'second']], u: 1000},
        {t: [['f', 3], ['f#'], ['f~']], u: 1}
    ],
    locale = (value, style = 'long') => {
        try {
            rtf = new Intl.RelativeTimeFormat(value, {style});
        } catch (e) {
            if (rtf) throw e;
            return;
        }
        const h = rtf.format(1, 'hour').split(' ');
        tokensRtf = new Set(rtf.format(1, 'day').split(' ')
            .filter(t => t != 1 && h.indexOf(t) > -1));
        return true;
    },
    fallback = (t, u) => u + ' ' + t.fmt + (u == 1 ? '' : 's'),
    mapper = {
        number: (t, u) => (u + '').padStart(t.fmt, '0'),
        string: (t, u) => rtf ? rtf.format(u, t.fmt).split(' ')
            .filter(t => !tokensRtf.has(t)).join(' ')
            .trim().replace(/[+-]/g, '') : fallback(t, u),
    },
    replace = (out, t) => out[t] || t.slice(1, t.length - 1),
    format = (pattern, value) => {
        if (typeof pattern !== 'string')
            throw Error('invalid pattern');
        if (!Number.isFinite(value))
            throw Error('invalid value');
        if (!pattern)
            return '';
        const out = {};
        value = Math.abs(value);
        pattern.match(tokens)?.forEach(t => out[t] = null);
        map.forEach(m => {
            let u = null;
            m.t.forEach(t => {
                if (out[t.token] !== null)
                    return;
                if (u === null) {
                    u = Math.floor(value / m.u);
                    value %= m.u;
                }
                out[t.token] = '' + (t.fn ? t.fn(t, u) : u);
            })
        });
        return pattern.replace(tokens, replace.bind(null, out));
    };
    map.forEach(m => m.t = m.t.map(t => ({
        token: t[0], fmt: t[1], fn: mapper[typeof t[1]]
    })));
    locale('en');
    return {format, locale};
})();


/************************** test below *************************/

const
cfg = {
  locale: 'en,de,nl,fr,it,es,pt,ro,ru,ja,kor,zh,th,hi',
  style: 'long,narrow'
},
el = id => document.getElementById(id),
locale = el('locale'), loc = el('loc'), style = el('style'),
fd = new Date(), td = el('td'), fmt = el('fmt'),
run = el('run'), out = el('out'),
test = () => {
  try {
      const tv = new Date(td.value);
      if (isNaN(tv)) throw Error('invalid "datetime2" value');
      timespan.locale(loc.value || locale.value, style.value);
      const delta = fd.getTime() - tv.getTime();
      out.innerHTML = timespan.format(fmt.value, delta);
  } catch (e) { out.innerHTML = e.message; }
};
el('fd').innerText = el('td').value = fd.toISOString();
el('fmt').value = 'D~ h~ m~ s~ f~ "ms"';
for (const [id, value] of Object.entries(cfg)) {
  const elm = el(id);
  value.split(',').forEach(i => elm.innerHTML += `<option>${i}</option>`);
}
_x000D_
i {color:green}
_x000D_
locale: <select id="locale"></select>
custom: <input id="loc" style="width:8em"><br>
style: <select id="style"></select><br>
datetime1: <i id="fd"></i><br>
datetime2: <input id="td"><br>
pattern: <input id="fmt">
<button id="run" onclick="test()">test</button><br><br>
<i id="out"></i>
_x000D_
_x000D_
_x000D_

Recursive search and replace in text files on Mac and Linux

OS X uses a mix of BSD and GNU tools, so best always check the documentation (although I had it that less didn't even conform to the OS X manpage):

https://web.archive.org/web/20170808213955/https://developer.apple.com/legacy/library/documentation/Darwin/Reference/ManPages/man1/sed.1.html

sed takes the argument after -i as the extension for backups. Provide an empty string (-i '') for no backups.

The following should do:

LC_ALL=C find . -type f -name '*.txt' -exec sed -i '' s/this/that/ {} +

The -type f is just good practice; sed will complain if you give it a directory or so. -exec is preferred over xargs; you needn't bother with -print0 or anything. The {} + at the end means that find will append all results as arguments to one instance of the called command, instead of re-running it for each result. (One exception is when the maximal number of command-line arguments allowed by the OS is breached; in that case find will run more than one instance.)

fastest MD5 Implementation in JavaScript

You could also check my md5 implementation. It should be approx. the same as the other posted above. Unfortunately, the performance is limited by the inner loop which is impossible to optimize more.

Non-recursive depth first search algorithm

You would use a stack that holds the nodes that were not visited yet:

stack.push(root)
while !stack.isEmpty() do
    node = stack.pop()
    for each node.childNodes do
        stack.push(stack)
    endfor
    // …
endwhile

How to drop a PostgreSQL database if there are active connections to it?

Depending on your version of postgresql you might run into a bug, that makes pg_stat_activity to omit active connections from dropped users. These connections are also not shown inside pgAdminIII.

If you are doing automatic testing (in which you also create users) this might be a probable scenario.

In this case you need to revert to queries like:

 SELECT pg_terminate_backend(procpid) 
 FROM pg_stat_get_activity(NULL::integer) 
 WHERE datid=(SELECT oid from pg_database where datname = 'your_database');

NOTE: In 9.2+ you'll have change procpid to pid.

Checking if sys.argv[x] is defined

A solution working with map built-in fonction !

arg_names = ['command' ,'operation', 'parameter']
args = map(None, arg_names, sys.argv)
args = {k:v for (k,v) in args}

Then you just have to call your parameters like this:

if args['operation'] == "division":
    if not args['parameter']:
        ...
    if args['parameter'] == "euclidian":
        ...