Programs & Examples On #Libdc1394

document.getElementById("test").style.display="hidden" not working

you can use something like this....div container

<script type="text/javascript">
function hide(){
document.getElementById("test").innerHTML.style.display="none";
}
</script>
<div id="test">
<form method="post" >

<table width="60%" border="0" cellspacing="2" cellpadding="2"  >
  <tr style="background:url(../images/nav.png) repeat-x; color:#fff; font-weight:bold" align="center">
    <td>Ample Id</td>
    <td>Find</td>
  </tr>

  <tr align="center" bgcolor="#E8F8FF" style="color:#006" >
    <td><input type="text" name="ampid" id="ampid" value="<?php echo $_POST['ampid'];?>" /></td>
   <td><input type="image" src="../images/btnFind.png" id="find" name="find" onclick="javascript:hide();"/></td>
   </tr>

</table>

</form>
</div>

What is an unhandled promise rejection?

In my case was Promise with no reject neither resolve, because my Promise function threw an exception. This mistake cause UnhandledPromiseRejectionWarning message.

How can I get a list of locally installed Python modules?

Solution

Do not use with pip > 10.0!

My 50 cents for getting a pip freeze-like list from a Python script:

import pip
installed_packages = pip.get_installed_distributions()
installed_packages_list = sorted(["%s==%s" % (i.key, i.version)
     for i in installed_packages])
print(installed_packages_list)

As a (too long) one liner:

sorted(["%s==%s" % (i.key, i.version) for i in pip.get_installed_distributions()])

Giving:

['behave==1.2.4', 'enum34==1.0', 'flask==0.10.1', 'itsdangerous==0.24', 
 'jinja2==2.7.2', 'jsonschema==2.3.0', 'markupsafe==0.23', 'nose==1.3.3', 
 'parse-type==0.3.4', 'parse==1.6.4', 'prettytable==0.7.2', 'requests==2.3.0',
 'six==1.6.1', 'vioozer-metadata==0.1', 'vioozer-users-server==0.1', 
 'werkzeug==0.9.4']

Scope

This solution applies to the system scope or to a virtual environment scope, and covers packages installed by setuptools, pip and (god forbid) easy_install.

My use case

I added the result of this call to my flask server, so when I call it with http://example.com/exampleServer/environment I get the list of packages installed on the server's virtualenv. It makes debugging a whole lot easier.

Caveats

I have noticed a strange behaviour of this technique - when the Python interpreter is invoked in the same directory as a setup.py file, it does not list the package installed by setup.py.

Steps to reproduce:

Create a virtual environment
$ cd /tmp
$ virtualenv test_env
New python executable in test_env/bin/python
Installing setuptools, pip...done.
$ source test_env/bin/activate
(test_env) $ 
Clone a git repo with setup.py
(test_env) $ git clone https://github.com/behave/behave.git
Cloning into 'behave'...
remote: Reusing existing pack: 4350, done.
remote: Total 4350 (delta 0), reused 0 (delta 0)
Receiving objects: 100% (4350/4350), 1.85 MiB | 418.00 KiB/s, done.
Resolving deltas: 100% (2388/2388), done.
Checking connectivity... done.

We have behave's setup.py in /tmp/behave:

(test_env) $ ls /tmp/behave/setup.py
/tmp/behave/setup.py
Install the python package from the git repo
(test_env) $ cd /tmp/behave && pip install . 
running install
...
Installed /private/tmp/test_env/lib/python2.7/site-packages/enum34-1.0-py2.7.egg
Finished processing dependencies for behave==1.2.5a1

If we run the aforementioned solution from /tmp

>>> import pip
>>> sorted(["%s==%s" % (i.key, i.version) for i in pip.get_installed_distributions()])
['behave==1.2.5a1', 'enum34==1.0', 'parse-type==0.3.4', 'parse==1.6.4', 'six==1.6.1']
>>> import os
>>> os.getcwd()
'/private/tmp'

If we run the aforementioned solution from /tmp/behave

>>> import pip
>>> sorted(["%s==%s" % (i.key, i.version) for i in pip.get_installed_distributions()])
['enum34==1.0', 'parse-type==0.3.4', 'parse==1.6.4', 'six==1.6.1']
>>> import os
>>> os.getcwd()
'/private/tmp/behave'

behave==1.2.5a1 is missing from the second example, because the working directory contains behave's setup.py file.

I could not find any reference to this issue in the documentation. Perhaps I shall open a bug for it.

ActiveXObject in Firefox or Chrome (not IE!)

ActiveX resolved in Chrome!
Hello all this is not the solution but the successful workaround and I have implemented as well.
This required some implementation on client machine as well that why is most suitable for intranet environment and not recommended for public sites. Even though one can implement it for public sites as well the only problem is end user has to download/implement solution.
Lets understand the key problem
Chrome cannot communicate with ActiceX
Solution: Since Chorme cannot communicate with ActiveX but still it can communicate with the API hosted on the client machine. So develop API using .Net MVC or any other technology so that through Ajax call it can communicate with the API and API communicate with the ActiveX object situated on the client machine. Since API also resides in Client machine that why there is no problem in communication. This API works as mediator between Chrome browser and ActiveX.
During API implementation you might encounter CORS issues, Use JSONP to deal with it.
Pictorial view of the solution Pictorial view of the solution


Other solution : Use URI Scheme like MailTo: or MS-Word to deal with outlook and word application. If your requirement is different then you can implement your customized URI Scheme.

How to insert default values in SQL table?

The best way is:

insert your_table
default values

How can I add an empty directory to a Git repository?

To extend Jamie Flournoy's solution to a directory tree, you can put this .gitignore in the top-level directory and touch .keepdir in each subdirectory that git should track. All other files are ignored. This is useful to ensure a consistent structure for build directories.

# Ignore files but not directories. * matches both files and directories
# but */ matches only directories. Both match at every directory level
# at or below this one.
*
!*/

# Git doesn't track empty directories, so track .keepdir files, which also 
# tracks the containing directory. 
!.keepdir

# Keep this file and the explanation of how this works
!.gitignore
!Readme.md

How to delete a localStorage item when the browser window/tab is closed?

localStorage.removeItem(key);  //item

localStorage.clear(); //all items

Postgresql SQL: How check boolean field with null and True,False Value?

I'm not expert enough in the inner workings of Postgres to know why your query with the double condition in the WHERE clause be not working. But one way to get around this would be to use a UNION of the two queries which you know do work:

SELECT * FROM table_name WHERE boolean_column IS NULL
UNION
SELECT * FROM table_name WHERE boolean_column = FALSE

You could also try using COALESCE:

SELECT * FROM table_name WHERE COALESCE(boolean_column, FALSE) = FALSE

This second query will replace all NULL values with FALSE and then compare against FALSE in the WHERE condition.

How to enable file upload on React's Material UI simple input?

Just the same as what should be but change the button component to be label like so

<form id='uploadForm'
      action='http://localhost:8000/upload'
      method='post'
      encType="multipart/form-data">
    <input type="file" id="sampleFile" style="display: none;" />
    <Button htmlFor="sampleFile" component="label" type={'submit'}>Upload</Button> 
</form>

jQuery not working with IE 11

Place this meta tag after head tag

<meta http-equiv="x-ua-compatible" content="IE=edge">

How to input a regex in string.replace?

The easiest way

import re

txt='this is a paragraph with<[1> in between</[1> and then there are cases ... where the<[99> number ranges from 1-100</[99>.  and there are many other lines in the txt files with<[3> such tags </[3>'

out = re.sub("(<[^>]+>)", '', txt)
print out

What is the difference between SQL and MySQL?

SQL is Structured Query Language

MySQL is a relational database management system. You can submit SQL queries to the MySQL database to store, retrieve, modify or delete data.

Capitalize first letter. MySQL

This is working nicely.

UPDATE state SET name = CONCAT(UCASE(LEFT(name, 1)), LCASE(SUBSTRING(name, 2)));

What is Java EE?

Java EE is actually a collection of technologies and APIs for the Java platform designed to support "Enterprise" Applications which can generally be classed as large-scale, distributed, transactional and highly-available applications designed to support mission-critical business requirements.

In terms of what an employee is looking for in specific techs, it is quite hard to say, because the playing field has kept changing over the last five years. It really is about the class of problems that are being solved more than anything else. Transactions and distribution are key.

How can I get the day of a specific date with PHP

$date = '2014-02-25';
date('D', strtotime($date));

Python - use list as function parameters

You can do this using the splat operator:

some_func(*params)

This causes the function to receive each list item as a separate parameter. There's a description here: http://docs.python.org/tutorial/controlflow.html#unpacking-argument-lists

In which case do you use the JPA @JoinTable annotation?

It's the only solution to map a ManyToMany association : you need a join table between the two entities tables to map the association.

It's also used for OneToMany (usually unidirectional) associations when you don't want to add a foreign key in the table of the many side and thus keep it independent of the one side.

Search for @JoinTable in the hibernate documentation for explanations and examples.

How to trigger a build only if changes happen on particular set of files

You can use Generic Webhook Trigger Plugin for this.

With a variable like changed_files and expression $.commits[*].['modified','added','removed'][*].

You can have a filter text like $changed_files and filter regexp like "folder/subfolder/[^"]+?" if folder/subfolder is the folder that should trigger builds.

How can I parse String to Int in an Angular expression?

You can use javascript Number method to parse it to an number,

var num=Number (num_str);

how to clear JTable

This is the fastest and easiest way that I have found;

while (tableModel.getRowCount()>0)
          {
             tableModel.removeRow(0);
          }

This clears the table lickety split and leaves it ready for new data.

Sticky and NON-Sticky sessions

I've made an answer with some more details here : https://stackoverflow.com/a/11045462/592477

Or you can read it there ==>

When you use loadbalancing it means you have several instances of tomcat and you need to divide loads.

  • If you're using session replication without sticky session : Imagine you have only one user using your web app, and you have 3 tomcat instances. This user sends several requests to your app, then the loadbalancer will send some of these requests to the first tomcat instance, and send some other of these requests to the secondth instance, and other to the third.
  • If you're using sticky session without replication : Imagine you have only one user using your web app, and you have 3 tomcat instances. This user sends several requests to your app, then the loadbalancer will send the first user request to one of the three tomcat instances, and all the other requests that are sent by this user during his session will be sent to the same tomcat instance. During these requests, if you shutdown or restart this tomcat instance (tomcat instance which is used) the loadbalancer sends the remaining requests to one other tomcat instance that is still running, BUT as you don't use session replication, the instance tomcat which receives the remaining requests doesn't have a copy of the user session then for this tomcat the user begin a session : the user loose his session and is disconnected from the web app although the web app is still running.
  • If you're using sticky session WITH session replication : Imagine you have only one user using your web app, and you have 3 tomcat instances. This user sends several requests to your app, then the loadbalancer will send the first user request to one of the three tomcat instances, and all the other requests that are sent by this user during his session will be sent to the same tomcat instance. During these requests, if you shutdown or restart this tomcat instance (tomcat instance which is used) the loadbalancer sends the remaining requests to one other tomcat instance that is still running, as you use session replication, the instance tomcat which receives the remaining requests has a copy of the user session then the user keeps on his session : the user continue to browse your web app without being disconnected, the shutdown of the tomcat instance doesn't impact the user navigation.

Convert Set to List without creating new List

Since it hasn't been mentioned so far, as of Java 10 you can use the new copyOf factory method:

List.copyOf(set);

From the Javadoc:

Returns an unmodifiable List containing the elements of the given Collection, in its iteration order.

Note that this creates a new list (ImmutableCollections$ListN to be precise) under the hood by

  1. calling Collection#toArray() on the given set and then
  2. putting these objects into a new array.

What is the simplest way to swap each pair of adjoining chars in a string with Python?

The usual way to swap two items in Python is:

a, b = b, a

So it would seem to me that you would just do the same with an extended slice. However, it is slightly complicated because strings aren't mutable; so you have to convert to a list and then back to a string.
Therefore, I would do the following:

>>> s = 'badcfe'
>>> t = list(s)
>>> t[::2], t[1::2] = t[1::2], t[::2]
>>> ''.join(t)
'abcdef'

phpmyadmin #1045 Cannot log in to the MySQL server. after installing mysql command line client

After like three (3) hours of google..ing.This is the solution to the problem: First, I run this command;

$mysqladmin -u root -p[your root password here] version Which outputs:

    Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.

    Oracle is a registered trademark of Oracle Corporation and/or its
    affiliates. Other names may be trademarks of their respective
    owners.

    Server version      5.5.49-0ubuntu0.14.04.1
    Protocol version    10
    Connection      Localhost via UNIX socket
    UNIX socket     /var/run/mysqld/mysqld.sock
    Uptime:         1 hour 54 min 3 sec

Finally, I changed the connect_type parameter from tcp to socket and added the parameter socket in config.inc.php:

    $cfg['Servers'][$i]['host'] = 'localhost';
    $cfg['Servers'][$i]['connect_type'] = 'socket';
    $cfg['Servers'][$i]['socket'] = '/var/run/mysqld/mysqld.sock';

All credit goes to this person: This is the correct solution

CMake complains "The CXX compiler identification is unknown"

I just had this problem setting up my new laptop. The issue for me was that my toolchain (CodeSourcery) is 32bit and I had not installed the 32bit libs.

sudo apt-get install ia32-libs

MySQL convert date string to Unix timestamp

For current date just use UNIX_TIMESTAMP() in your MySQL query.

How to append contents of multiple files into one file

If you want to append contents of 3 files into one file, then the following command will be a good choice:

cat file1 file2 file3 | tee -a file4 > /dev/null

It will combine the contents of all files into file4, throwing console output to /dev/null.

Check if current date is between two dates Oracle SQL

TSQL: Dates- need to look for gaps in dates between Two Date

select
distinct
e1.enddate,
e3.startdate,
DATEDIFF(DAY,e1.enddate,e3.startdate)-1 as [Datediff]
from #temp e1 
   join #temp e3 on e1.enddate < e3.startdate          
       /* Finds the next start Time */
and e3.startdate = (select min(startdate) from #temp e5
where e5.startdate > e1.enddate)
and not exists (select *  /* Eliminates e1 rows if it is overlapped */
from #temp e5 
where e5.startdate < e1.enddate and e5.enddate > e1.enddate);

Get the last 4 characters of a string

str = "aaaaabbbb"
newstr = str[-4:]

See : http://codepad.org/S3zjnKoD

Show Console in Windows Application?

Disclaimer

There is a way to achieve this which is quite simple, but I wouldn't suggest it is a good approach for an app you are going to let other people see. But if you had some developer need to show the console and windows forms at the same time, it can be done quite easily.

This method also supports showing only the Console window, but does not support showing only the Windows Form - i.e. the Console will always be shown. You can only interact (i.e. receive data - Console.ReadLine(), Console.Read()) with the console window if you do not show the windows forms; output to Console - Console.WriteLine() - works in both modes.

This is provided as is; no guarantees this won't do something horrible later on, but it does work.

Project steps

Start from a standard Console Application.

Mark the Main method as [STAThread]

Add a reference in your project to System.Windows.Forms

Add a Windows Form to your project.

Add the standard Windows start code to your Main method:

End Result

You will have an application that shows the Console and optionally windows forms.

Sample Code

Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace ConsoleApplication9 {
    class Program {

        [STAThread]
        static void Main(string[] args) {

            if (args.Length > 0 && args[0] == "console") {
                Console.WriteLine("Hello world!");
                Console.ReadLine();
            }
            else {
                Application.EnableVisualStyles(); 
                Application.SetCompatibleTextRenderingDefault(false); 
                Application.Run(new Form1());
            }
        }
    }
}

Form1.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace ConsoleApplication9 {
    public partial class Form1 : Form {
        public Form1() {
            InitializeComponent();
        }

        private void Form1_Click(object sender, EventArgs e) {
            Console.WriteLine("Clicked");
        }
    }
}

jQuery's .click - pass parameters to user function

      $imgReload.data('self', $self);
            $imgReload.click(function (e) {
                var $p = $(this).data('self');
                $p._reloadTable();
            });

Set javaScript object to onclick element:

 $imgReload.data('self', $self);

get Object from "this" element:

 var $p = $(this).data('self');

Python ValueError: too many values to unpack

Iterating over a dictionary object itself actually gives you an iterator over its keys. Python is trying to unpack keys, which you get from m.type + m.purity into (m, k).

My crystal ball says m.type and m.purity are both strings, so your keys are also strings. Strings are iterable, so they can be unpacked; but iterating over the string gives you an iterator over its characters. So whenever m.type + m.purity is more than two characters long, you have too many values to unpack. (And whenever it's shorter, you have too few values to unpack.)

To fix this, you can iterate explicitly over the items of the dict, which are the (key, value) pairs that you seem to be expecting. But if you only want the values, then just use the values.

(In 2.x, itervalues, iterkeys, and iteritems are typically a better idea; the non-iter versions create a new list object containing the values/keys/items. For large dictionaries and trivial tasks within the iteration, this can be a lot slower than the iter versions which just set up an iterator.)

Show Image View from file path?

You can use:

ImageView imgView = new ImageView(this);
InputStream is = getClass().getResourceAsStream("/drawable/" + fileName);
imgView.setImageDrawable(Drawable.createFromStream(is, ""));

How to execute a program or call a system command from Python

To fetch the network id from the OpenStack Neutron:

#!/usr/bin/python
import os
netid = "nova net-list | awk '/ External / { print $2 }'"
temp = os.popen(netid).read()  /* Here temp also contains new line (\n) */
networkId = temp.rstrip()
print(networkId)

Output of nova net-list

+--------------------------------------+------------+------+
| ID                                   | Label      | CIDR |
+--------------------------------------+------------+------+
| 431c9014-5b5d-4b51-a357-66020ffbb123 | test1      | None |
| 27a74fcd-37c0-4789-9414-9531b7e3f126 | External   | None |
| 5a2712e9-70dc-4b0e-9281-17e02f4684c9 | management | None |
| 7aa697f5-0e60-4c15-b4cc-9cb659698512 | Internal   | None |
+--------------------------------------+------------+------+

Output of print(networkId)

27a74fcd-37c0-4789-9414-9531b7e3f126

LaTeX "\indent" creating paragraph indentation / tabbing package requirement?

This is kind of a hack but the best solution that I have found is to use a description tag with no \item. This will produce an error from the latex compiler; however, the error does not prevent the pdf from being generated.

\begin{description} 
     <YOUR TEXT HERE> 
\end{description}
  • This only worked on windows latex compiler

Select and display only duplicate records in MySQL

SELECT id, payer_email FROM paypal_ipn_orders
WHERE payer_email IN (
    SELECT payer_email FROM papypal_ipn_orders GROUP BY payer_email HAVING COUNT(*) > 1)

What does the "~" (tilde/squiggle/twiddle) CSS selector mean?

General sibling combinator

The general sibling combinator selector is very similar to the adjacent sibling combinator selector. The difference is that the element being selected doesn't need to immediately succeed the first element, but can appear anywhere after it.

More info

Use RSA private key to generate public key?

Seems to be a common feature of the prevalent asymmetric cryptography; the generation of public/private keys involves generating the private key, which contains the key pair:

openssl genrsa -out mykey.pem 1024

Then publish the public key:

openssl rsa -in mykey.pem -pubout > mykey.pub

or

openssl rsa -in mykey.pem -pubout -out mykey.pub

DSA & EC crypto keys have same feature: eg.

openssl genpkey -algorithm ed25519 -out pvt.pem

Then

openssl pkey -in pvt.pem -pubout > public.pem

or

openssl ec -in ecprivkey.pem -pubout -out ecpubkey.pem

The public component is involved in decryption, and keeping it as part of the private key makes decryption faster; it can be removed from the private key and calculated when needed (for decryption), as an alternative or complement to encrypting or protecting the private key with a password/key/phrase. eg.

openssl pkey -in key.pem -des3 -out keyout.pem

or

openssl ec -aes-128-cbc -in pk8file.pem -out tradfile.pem

You can replace the first argument "aes-128-cbc" with any other valid openssl cipher name

How to filter Android logcat by application?

The log cat output can be filtered to only display messages from your package by using these arguments.

adb com.your.package:I *:s

Edit - I spoke to soon.

adb com.your.package:v

Position: absolute and parent height?

If I understand what you're trying to do correctly, then I don't think this is possible with CSS while keeping the children absolutely positioned.

Absolutely positioned elements are completely removed from the document flow, and thus their dimensions cannot alter the dimensions of their parents.

If you really had to achieve this affect while keeping the children as position: absolute, you could do so with JavaScript by finding the height of the absolutely positioned children after they have rendered, and using that to set the height of the parent.

Alternatively, just use float: left/float:right and margins to get the same positioning effect while keeping the children in the document flow, you can then use overflow: hidden on the parent (or any other clearfix technique) to cause its height to expand to that of its children.

article {
    position: relative;
    overflow: hidden;
}

.one {
    position: relative;
    float: left;
    margin-top: 10px;
    margin-left: 10px;
    background: red;
    width: 30px;
    height: 30px;
}

.two {
    position: relative;
    float: right;
    margin-top: 10px;
    margin-right: 10px;
    background: blue;
    width: 30px;
    height: 30px;
}

VBA procedure to import csv file into access

Your file seems quite small (297 lines) so you can read and write them quite quickly. You refer to Excel CSV, which does not exists, and you show space delimited data in your example. Furthermore, Access is limited to 255 columns, and a CSV is not, so there is no guarantee this will work

Sub StripHeaderAndFooter()
Dim fs As Object ''FileSystemObject
Dim tsIn As Object, tsOut As Object ''TextStream
Dim sFileIn As String, sFileOut As String
Dim aryFile As Variant

    sFileIn = "z:\docs\FileName.csv"
    sFileOut = "z:\docs\FileOut.csv"

    Set fs = CreateObject("Scripting.FileSystemObject")
    Set tsIn = fs.OpenTextFile(sFileIn, 1) ''ForReading

    sTmp = tsIn.ReadAll

    Set tsOut = fs.CreateTextFile(sFileOut, True) ''Overwrite
    aryFile = Split(sTmp, vbCrLf)

    ''Start at line 3 and end at last line -1
    For i = 3 To UBound(aryFile) - 1
        tsOut.WriteLine aryFile(i)
    Next

    tsOut.Close

    DoCmd.TransferText acImportDelim, , "NewCSV", sFileOut, False
End Sub

Edit re various comments

It is possible to import a text file manually into MS Access and this will allow you to choose you own cell delimiters and text delimiters. You need to choose External data from the menu, select your file and step through the wizard.

About importing and linking data and database objects -- Applies to: Microsoft Office Access 2003

Introduction to importing and exporting data -- Applies to: Microsoft Access 2010

Once you get the import working using the wizards, you can save an import specification and use it for you next DoCmd.TransferText as outlined by @Olivier Jacot-Descombes. This will allow you to have non-standard delimiters such as semi colon and single-quoted text.

Why do you need ./ (dot-slash) before executable or script name to run it in bash?

Because on Unix, usually, the current directory is not in $PATH.

When you type a command the shell looks up a list of directories, as specified by the PATH variable. The current directory is not in that list.

The reason for not having the current directory on that list is security.

Let's say you're root and go into another user's directory and type sl instead of ls. If the current directory is in PATH, the shell will try to execute the sl program in that directory (since there is no other sl program). That sl program might be malicious.

It works with ./ because POSIX specifies that a command name that contain a / will be used as a filename directly, suppressing a search in $PATH. You could have used full path for the exact same effect, but ./ is shorter and easier to write.

EDIT

That sl part was just an example. The directories in PATH are searched sequentially and when a match is made that program is executed. So, depending on how PATH looks, typing a normal command may or may not be enough to run the program in the current directory.

Returning an array using C

In your case, you are creating an array on the stack and once you leave the function scope, the array will be deallocated. Instead, create a dynamically allocated array and return a pointer to it.

char * returnArray(char *arr, int size) {
    char *new_arr = malloc(sizeof(char) * size);
    for(int i = 0; i < size; ++i) {
        new_arr[i] = arr[i];
    }
    return new_arr;
}

int main() {

    char arr[7]= {1,0,0,0,0,1,1};
    char *new_arr = returnArray(arr, 7);

    // don't forget to free the memory after you're done with the array
    free(new_arr);

}

Angular window resize event

Assuming that < 600px means mobile to you, you can use this observable and subscribe to it:

First we need the current window size. So we create an observable which only emits a single value: the current window size.

initial$ = Observable.of(window.innerWidth > 599 ? false : true);

Then we need to create another observable, so that we know when the window size was changed. For this we can use the "fromEvent" operator. To learn more about rxjs`s operators please visit: rxjs

resize$ = Observable.fromEvent(window, 'resize').map((event: any) => {
  return event.target.innerWidth > 599 ? false : true;
 });

Merg these two streams to receive our observable:

mobile$ = Observable.merge(this.resize$, this.initial$).distinctUntilChanged();

Now you can subscribe to it like this:

mobile$.subscribe((event) => { console.log(event); });

Remember to unsubscribe :)

td widths, not working?

This problem is quite easily solved using min-width and max-width within a css rule.

HTML

<table>
  <tr>
    <td class="name">Peter</td>
    <td class="hobby">Photography</td>
    <td class="comment">A long comment about something...</td>
  </td>
</table>

CSS

.name {
  max-width: 80px;
  min-width: 80px;
}

This will force the first column to be 80px wide. Usually I only use max-width without min-width to reign in text that is very occasionally too long from creating a table that has a super wide column that is mostly empty. The OP's question was about setting to a fixed width though, hence both rules together. On many browsers width:80px; in CSS is ignored for table columns. Setting the width within the HTML does work, but is not the way you should do things.

I would recommend using min and max width rules, and not set them the same but rather set a range. This way the table can do it's thing, but you can give it some hints on what to do with overly long content.

If I want to keep the text from wrapping and increasing the height of a row - but still make it possible for a user to see the full text, I use white-space: nowrap; on the main rule, then apply a hover rule that removes the width and nowrap rules so that the user can see the full content when they over their mouse over it. Something like this:

CSS

.name {
  max-width: 80px;
  white-space: nowrap;
  overflow: hidden;
}
.name:hover {
  max-width: none;
  white-space: normal;
  overflow:auto;
}

It just depends on exactly what you are trying to achieve. I hope this helps someone. PS As an aside, for iOS there is a fix for hover not working - see CSS Hover Not Working on iOS Safari and Chrome

Java: how do I check if a Date is within a certain range?

boolean isWithinRange(Date testDate) {
   return !(testDate.before(startDate) || testDate.after(endDate));
}

Doesn't seem that awkward to me. Note that I wrote it that way instead of

return testDate.after(startDate) && testDate.before(endDate);

so it would work even if testDate was exactly equal to one of the end cases.

How can I shuffle an array?

Use the modern version of the Fisher–Yates shuffle algorithm:

/**
 * Shuffles array in place.
 * @param {Array} a items An array containing the items.
 */
function shuffle(a) {
    var j, x, i;
    for (i = a.length - 1; i > 0; i--) {
        j = Math.floor(Math.random() * (i + 1));
        x = a[i];
        a[i] = a[j];
        a[j] = x;
    }
    return a;
}

ES2015 (ES6) version

/**
 * Shuffles array in place. ES6 version
 * @param {Array} a items An array containing the items.
 */
function shuffle(a) {
    for (let i = a.length - 1; i > 0; i--) {
        const j = Math.floor(Math.random() * (i + 1));
        [a[i], a[j]] = [a[j], a[i]];
    }
    return a;
}

Note however, that swapping variables with destructuring assignment causes significant performance loss, as of October 2017.

Use

var myArray = ['1','2','3','4','5','6','7','8','9'];
shuffle(myArray);

Implementing prototype

Using Object.defineProperty (method taken from this SO answer) we can also implement this function as a prototype method for arrays, without having it show up in loops such as for (i in arr). The following will allow you to call arr.shuffle() to shuffle the array arr:

Object.defineProperty(Array.prototype, 'shuffle', {
    value: function() {
        for (let i = this.length - 1; i > 0; i--) {
            const j = Math.floor(Math.random() * (i + 1));
            [this[i], this[j]] = [this[j], this[i]];
        }
        return this;
    }
});

Changing button text onclick

Or more simple without having to name the element (with 'button' element):

<button onclick="toggleLog(this)">Stop logs</button>

and script :

var bWriteLog = true;

function toggleLog(elt) {

  bWriteLog = !bWriteLog;
  elt.innerHTML = bWriteLog ? 'Stop logs' : 'Watch logs';
}

Can someone explain Microsoft Unity?

I am covering most of the examples of Dependency Injection in ASP.NET Web API 2

public interface IShape
{
    string Name { get; set; }
}

public class NoShape : IShape
{
    public string Name { get; set; } = "I have No Shape";
}

public class Circle : IShape
{
    public string Name { get; set; } = "Circle";
}

public class Rectangle : IShape
{
    public Rectangle(string name)
    {
        this.Name = name;
    }

    public string Name { get; set; } = "Rectangle";
}

In DIAutoV2Controller.cs Auto Injection mechanism is used

[RoutePrefix("api/v2/DIAutoExample")]
public class DIAutoV2Controller : ApiController
{
    private string ConstructorInjected;
    private string MethodInjected1;
    private string MethodInjected2;
    private string MethodInjected3;

    [Dependency]
    public IShape NoShape { get; set; }

    [Dependency("Circle")]
    public IShape ShapeCircle { get; set; }

    [Dependency("Rectangle")]
    public IShape ShapeRectangle { get; set; }

    [Dependency("PiValueExample1")]
    public double PiValue { get; set; }

    [InjectionConstructor]
    public DIAutoV2Controller([Dependency("Circle")]IShape shape1, [Dependency("Rectangle")]IShape shape2, IShape shape3)
    {
        this.ConstructorInjected = shape1.Name + " & " + shape2.Name + " & " + shape3.Name;
    }

    [NonAction]
    [InjectionMethod]
    public void Initialize()
    {
        this.MethodInjected1 = "Default Initialize done";
    }

    [NonAction]
    [InjectionMethod]
    public void Initialize2([Dependency("Circle")]IShape shape1)
    {
        this.MethodInjected2 = shape1.Name;
    }

    [NonAction]
    [InjectionMethod]
    public void Initialize3(IShape shape1)
    {
        this.MethodInjected3 = shape1.Name;
    }

    [HttpGet]
    [Route("constructorinjection")]
    public string constructorinjection()
    {
        return "Constructor Injected: " + this.ConstructorInjected;
    }

    [HttpGet]
    [Route("GetNoShape")]
    public string GetNoShape()
    {
        return "Property Injected: " + this.NoShape.Name;
    }

    [HttpGet]
    [Route("GetShapeCircle")]
    public string GetShapeCircle()
    {
        return "Property Injected: " + this.ShapeCircle.Name;
    }

    [HttpGet]
    [Route("GetShapeRectangle")]
    public string GetShapeRectangle()
    {
        return "Property Injected: " + this.ShapeRectangle.Name;
    }

    [HttpGet]
    [Route("GetPiValue")]
    public string GetPiValue()
    {
        return "Property Injected: " + this.PiValue;
    }

    [HttpGet]
    [Route("MethodInjected1")]
    public string InjectionMethod1()
    {
        return "Method Injected: " + this.MethodInjected1;
    }

    [HttpGet]
    [Route("MethodInjected2")]
    public string InjectionMethod2()
    {
        return "Method Injected: " + this.MethodInjected2;
    }

    [HttpGet]
    [Route("MethodInjected3")]
    public string InjectionMethod3()
    {
        return "Method Injected: " + this.MethodInjected3;
    }
}

In DIV2Controller.cs everything will be injected from the Dependency Configuration Resolver class

[RoutePrefix("api/v2/DIExample")]
public class DIV2Controller : ApiController
{
    private string ConstructorInjected;
    private string MethodInjected1;
    private string MethodInjected2;
    public string MyPropertyName { get; set; }
    public double PiValue1 { get; set; }
    public double PiValue2 { get; set; }
    public IShape Shape { get; set; }

    // MethodInjected
    [NonAction]
    public void Initialize()
    {
        this.MethodInjected1 = "Default Initialize done";
    }

    // MethodInjected
    [NonAction]
    public void Initialize2(string myproperty1, IShape shape1, string myproperty2, IShape shape2)
    {
        this.MethodInjected2 = myproperty1 + " & " + shape1.Name + " & " + myproperty2 + " & " + shape2.Name;
    }

    public DIV2Controller(string myproperty1, IShape shape1, string myproperty2, IShape shape2)
    {
        this.ConstructorInjected = myproperty1 + " & " + shape1.Name + " & " + myproperty2 + " & " + shape2.Name;
    }

    [HttpGet]
    [Route("constructorinjection")]
    public string constructorinjection()
    {
        return "Constructor Injected: " + this.ConstructorInjected;
    }

    [HttpGet]
    [Route("PropertyInjected")]
    public string InjectionProperty()
    {
        return "Property Injected: " + this.MyPropertyName;
    }

    [HttpGet]
    [Route("GetPiValue1")]
    public string GetPiValue1()
    {
        return "Property Injected: " + this.PiValue1;
    }

    [HttpGet]
    [Route("GetPiValue2")]
    public string GetPiValue2()
    {
        return "Property Injected: " + this.PiValue2;
    }

    [HttpGet]
    [Route("GetShape")]
    public string GetShape()
    {
        return "Property Injected: " + this.Shape.Name;
    }

    [HttpGet]
    [Route("MethodInjected1")]
    public string InjectionMethod1()
    {
        return "Method Injected: " + this.MethodInjected1;
    }

    [HttpGet]
    [Route("MethodInjected2")]
    public string InjectionMethod2()
    {
        return "Method Injected: " + this.MethodInjected2;
    }
}

Configuring the Dependency Resolver

public static void Register(HttpConfiguration config)
{
    var container = new UnityContainer();
    RegisterInterfaces(container);
    config.DependencyResolver = new UnityResolver(container);

    // Other Web API configuration not shown.
}

private static void RegisterInterfaces(UnityContainer container)
{
    var dbContext = new SchoolDbContext();
    // Registration with constructor injection
    container.RegisterType<IStudentRepository, StudentRepository>(new InjectionConstructor(dbContext));
    container.RegisterType<ICourseRepository, CourseRepository>(new InjectionConstructor(dbContext));

    // Set constant/default value of Pi = 3.141 
    container.RegisterInstance<double>("PiValueExample1", 3.141);
    container.RegisterInstance<double>("PiValueExample2", 3.14);

    // without a name
    container.RegisterInstance<IShape>(new NoShape());

    // with circle name
    container.RegisterType<IShape, Circle>("Circle", new InjectionProperty("Name", "I am Circle"));

    // with rectangle name
    container.RegisterType<IShape, Rectangle>("Rectangle", new InjectionConstructor("I am Rectangle"));

    // Complex type like Constructor, Property and method injection
    container.RegisterType<DIV2Controller, DIV2Controller>(
        new InjectionConstructor("Constructor Value1", container.Resolve<IShape>("Circle"), "Constructor Value2", container.Resolve<IShape>()),
        new InjectionMethod("Initialize"),
        new InjectionMethod("Initialize2", "Value1", container.Resolve<IShape>("Circle"), "Value2", container.Resolve<IShape>()),
        new InjectionProperty("MyPropertyName", "Property Value"),
        new InjectionProperty("PiValue1", container.Resolve<double>("PiValueExample1")),
        new InjectionProperty("Shape", container.Resolve<IShape>("Rectangle")),
        new InjectionProperty("PiValue2", container.Resolve<double>("PiValueExample2")));
}

How to resolve the error "Unable to access jarfile ApacheJMeter.jar errorlevel=1" while initiating Jmeter?

If you are using linux and faced such problem during creating link, try to change jar file path of original jmeter file.

+ java -server -XX:+HeapDumpOnOutOfMemoryError -Xms512m -Xmx512m -XX:NewSize=128m -XX:MaxNewSize=128m -XX:MaxTenuringThreshold=2 -XX:PermSize=64m -XX:MaxPermSize=128m -XX:+CMSClassUnloadingEnabled -jar ./ApacheJMeter.jar -help

Change to:

java $ARGS $JVM_ARGS -jar "/opt/apache-jmeter-2.11/bin/ApacheJMeter.jar" "$@"

Creating csv file with php

Its blank because you are writing to file. you should write to output using php://output instead and also send header information to indicate that it's csv.

Example

header('Content-Type: text/csv');
header('Content-Disposition: attachment; filename="sample.csv"');
$data = array(
        'aaa,bbb,ccc,dddd',
        '123,456,789',
        '"aaa","bbb"'
);

$fp = fopen('php://output', 'wb');
foreach ( $data as $line ) {
    $val = explode(",", $line);
    fputcsv($fp, $val);
}
fclose($fp);

If statement in select (ORACLE)

In one line, answer is as below;

[ CASE WHEN COLUMN_NAME = 'VALUE' THEN 'SHOW_THIS' ELSE 'SHOW_OTHER' END as ALIAS ]

Is there a Python equivalent of the C# null-coalescing operator?

In addition to Juliano's answer about behavior of "or": it's "fast"

>>> 1 or 5/0
1

So sometimes it's might be a useful shortcut for things like

object = getCachedVersion() or getFromDB()

how to download file using AngularJS and calling MVC API?

per various post... you cannot trigger a download via XHR. I needed to implement condition for the download, so, My solution was:

//make the call to the api with the ID to validate
someResource.get( { id: someId }, function(data) {
     //confirm that the ID is validated
     if (data.isIdConfirmed) {
         //get the token from the validation and issue another call
         //to trigger the download
         window.open('someapi/print/:someId?token='+ data.token);
     }
});

I wish that somehow, or someday the download can be triggered using XHR to avoid the second call. // _e

Delete with Join in MySQL

Or the same thing, with a slightly different (IMO friendlier) syntax:

DELETE FROM posts 
USING posts, projects 
WHERE projects.project_id = posts.project_id AND projects.client_id = :client_id;

BTW, with mysql using joins is almost always a way faster than subqueries...

How can I convert a series of images to a PDF from the command line on linux?

Using imagemagick, you can try:

convert page.png page.pdf

Or for multiple images:

convert page*.png mydoc.pdf

How to change the name of an iOS app?

This is how I changed in Xcode 4:

  1. Click on your Target file (First Main file of the application).
  2. Go to Build Settings.
  3. Scroll down you will find a bar called "Packaging".
  4. Under Packaging you will see Product Name, you can change project name.

Reset par to the default values at startup

This is hacky, but:

resetPar <- function() {
    dev.new()
    op <- par(no.readonly = TRUE)
    dev.off()
    op
}

works after a fashion, but it does flash a new device on screen temporarily...

E.g.:

> par(mfrow = c(2,2)) ## some random par change
> par("mfrow")
[1] 2 2
> par(resetPar())     ## reset the pars to defaults
> par("mfrow")        ## back to default
[1] 1 1

How to align the checkbox and label in same line in html?

None of these suggestions above worked for me as-is. I had to use the following to center a checkbox with the label text displayed to the right of the box:

<style>
.checkboxes {
  display: flex;
  justify-content: center;
  align-items: center;
  vertical-align: middle;
  word-wrap: break-word;
}
</style>

<label for="checkbox1" class="checkboxes"><input type="checkbox" id="checkbox1" name="checked" value="yes" class="checkboxes"/>
Check the box.</label>

What is the equivalent to a JavaScript setInterval/setTimeout in Android/Java?

setInterval()

function that repeats itself in every n milliseconds

Javascript

 setInterval(function(){ Console.log("A Kiss every 5 seconds"); }, 5000);

Approximate java Equivalent

new Timer().scheduleAtFixedRate(new TimerTask(){
    @Override
    public void run(){
       Log.i("tag", "A Kiss every 5 seconds");
    }
},0,5000);

setTimeout()

function that works only after n milliseconds

Javascript

setTimeout(function(){ Console.log("A Kiss after 5 seconds"); },5000);

Approximate java Equivalent

new android.os.Handler().postDelayed(
    new Runnable() {
        public void run() {
            Log.i("tag","A Kiss after 5 seconds");
        }
}, 5000);

What are the differences between delegates and events?

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

Definitions:

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

Regarding the adjective protected:

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

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

Code Example:

with delegate:

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

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

with event:

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

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

Reference:

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

Side-by-side plots with ggplot2

You can use the following multiplot function from Winston Chang's R cookbook

multiplot(plot1, plot2, cols=2)

multiplot <- function(..., plotlist=NULL, cols) {
    require(grid)

    # Make a list from the ... arguments and plotlist
    plots <- c(list(...), plotlist)

    numPlots = length(plots)

    # Make the panel
    plotCols = cols                          # Number of columns of plots
    plotRows = ceiling(numPlots/plotCols) # Number of rows needed, calculated from # of cols

    # Set up the page
    grid.newpage()
    pushViewport(viewport(layout = grid.layout(plotRows, plotCols)))
    vplayout <- function(x, y)
        viewport(layout.pos.row = x, layout.pos.col = y)

    # Make each plot, in the correct location
    for (i in 1:numPlots) {
        curRow = ceiling(i/plotCols)
        curCol = (i-1) %% plotCols + 1
        print(plots[[i]], vp = vplayout(curRow, curCol ))
    }

}

Pass an array of integers to ASP.NET Web API?

You may try this code for you to take comma separated values / an array of values to get back a JSON from webAPI

 public class CategoryController : ApiController
 {
     public List<Category> Get(String categoryIDs)
     {
         List<Category> categoryRepo = new List<Category>();

         String[] idRepo = categoryIDs.Split(',');

         foreach (var id in idRepo)
         {
             categoryRepo.Add(new Category()
             {
                 CategoryID = id,
                 CategoryName = String.Format("Category_{0}", id)
             });
         }
         return categoryRepo;
     }
 }

 public class Category
 {
     public String CategoryID { get; set; }
     public String CategoryName { get; set; }
 } 

Output :

[
{"CategoryID":"4","CategoryName":"Category_4"}, 
{"CategoryID":"5","CategoryName":"Category_5"}, 
{"CategoryID":"3","CategoryName":"Category_3"} 
]

Why do I get "a label can only be part of a statement and a declaration is not a statement" if I have a variable that is initialized after a label?

This is a quirk of the C grammar. A label (Cleanup:) is not allowed to appear immediately before a declaration (such as char *str ...;), only before a statement (printf(...);). In C89 this was no great difficulty because declarations could only appear at the very beginning of a block, so you could always move the label down a bit and avoid the issue. In C99 you can mix declarations and code, but you still can't put a label immediately before a declaration.

You can put a semicolon immediately after the label's colon (as suggested by Renan) to make there be an empty statement there; this is what I would do in machine-generated code. Alternatively, hoist the declaration to the top of the function:

int main (void) 
{
    char *str;
    printf("Hello ");
    goto Cleanup;
Cleanup:
    str = "World\n";
    printf("%s\n", str);
    return 0;
}

Is it possible to execute multiple _addItem calls asynchronously using Google Analytics?

From the docs:

_trackTrans() Sends both the transaction and item data to the Google Analytics server. This method should be called after _trackPageview(), and used in conjunction with the _addItem() and addTrans() methods. It should be called after items and transaction elements have been set up.

So, according to the docs, the items get sent when you call trackTrans(). Until you do, you can add items, but the transaction will not be sent.

Edit: Further reading led me here:

http://www.analyticsmarket.com/blog/edit-ecommerce-data

Where it clearly says you can start another transaction with an existing ID. When you commit it, the new items you listed will be added to that transaction.

Global and local variables in R

Variables declared inside a function are local to that function. For instance:

foo <- function() {
    bar <- 1
}
foo()
bar

gives the following error: Error: object 'bar' not found.

If you want to make bar a global variable, you should do:

foo <- function() {
    bar <<- 1
}
foo()
bar

In this case bar is accessible from outside the function.

However, unlike C, C++ or many other languages, brackets do not determine the scope of variables. For instance, in the following code snippet:

if (x > 10) {
    y <- 0
}
else {
    y <- 1
}

y remains accessible after the if-else statement.

As you well say, you can also create nested environments. You can have a look at these two links for understanding how to use them:

  1. http://stat.ethz.ch/R-manual/R-devel/library/base/html/environment.html
  2. http://stat.ethz.ch/R-manual/R-devel/library/base/html/get.html

Here you have a small example:

test.env <- new.env()

assign('var', 100, envir=test.env)
# or simply
test.env$var <- 100

get('var') # var cannot be found since it is not defined in this environment
get('var', envir=test.env) # now it can be found

How to get the type of T from a member of a generic class or method?

If you want to know a property's underlying type, try this:

propInfo.PropertyType.UnderlyingSystemType.GenericTypeArguments[0]

Plot a bar using matplotlib using a dictionary

Why not just:

import seaborn as sns

sns.barplot(list(D.keys()), list(D.values()))

Uncaught (in promise): Error: StaticInjectorError(AppModule)[options]

Here is what worked for me (Angular 7):

First import HttpClientModule in your app.module.ts if you didn't:

import { HttpClientModule } from '@angular/common/http';
...
imports: [
        HttpClientModule
    ],

Then change your service

@Injectable()
export class FooService {

to

@Injectable({
    providedIn: 'root'
})
export class FooService {

Hope it helps.

Edit:

providedIn

Determines which injectors will provide the injectable, by either associating it with an @NgModule or other InjectorType, or by specifying that this injectable should be provided in one of the following injectors:

'root' : The application-level injector in most apps.

'platform' : A special singleton platform injector shared by all applications on the page.

'any' : Provides a unique instance in every module (including lazy modules) that injects the token.

Be careful platform is available only since Angular 9 (https://blog.angular.io/version-9-of-angular-now-available-project-ivy-has-arrived-23c97b63cfa3)

Read more about Injectable here: https://angular.io/api/core/Injectable

ArrayList or List declaration in Java

It is easy to change the implementation to List to Set:

Collection<String> stringList = new ArrayList<String>();
//Client side
stringList = new LinkedList<String>();

stringList = new HashSet<String>();
//stringList = new HashSet<>(); java 1.7 and 1.8

How to check if an object is a certain type

Some more details in relation with the response from Cody Gray. As it took me some time to digest it I though it might be usefull to others.

First, some definitions:

  1. There are TypeNames, which are string representations of the type of an object, interface, etc. For example, Bar is a TypeName in Public Class Bar, or in Dim Foo as Bar. TypeNames could be seen as "labels" used in the code to tell the compiler which type definition to look for in a dictionary where all available types would be described.
  2. There are System.Type objects which contain a value. This value indicates a type; just like a String would take some text or an Int would take a number, except we are storing types instead of text or numbers. Type objects contain the type definitions, as well as its corresponding TypeName.

Second, the theory:

  1. Foo.GetType() returns a Type object which contains the type for the variable Foo. In other words, it tells you what Foo is an instance of.
  2. GetType(Bar) returns a Type object which contains the type for the TypeName Bar.
  3. In some instances, the type an object has been Cast to is different from the type an object was first instantiated from. In the following example, MyObj is an Integer cast into an Object:

    Dim MyVal As Integer = 42 Dim MyObj As Object = CType(MyVal, Object)

So, is MyObj of type Object or of type Integer? MyObj.GetType() will tell you it is an Integer.

  1. But here comes the Type Of Foo Is Bar feature, which allows you to ascertain a variable Foo is compatible with a TypeName Bar. Type Of MyObj Is Integer and Type Of MyObj Is Object will both return True. For most cases, TypeOf will indicate a variable is compatible with a TypeName if the variable is of that Type or a Type that derives from it. More info here: https://docs.microsoft.com/en-us/dotnet/visual-basic/language-reference/operators/typeof-operator#remarks

The test below illustrate quite well the behaviour and usage of each of the mentionned keywords and properties.

Public Sub TestMethod1()

    Dim MyValInt As Integer = 42
    Dim MyValDble As Double = CType(MyValInt, Double)
    Dim MyObj As Object = CType(MyValDble, Object)

    Debug.Print(MyValInt.GetType.ToString) 'Returns System.Int32
    Debug.Print(MyValDble.GetType.ToString) 'Returns System.Double
    Debug.Print(MyObj.GetType.ToString) 'Returns System.Double

    Debug.Print(MyValInt.GetType.GetType.ToString) 'Returns System.RuntimeType
    Debug.Print(MyValDble.GetType.GetType.ToString) 'Returns System.RuntimeType
    Debug.Print(MyObj.GetType.GetType.ToString) 'Returns System.RuntimeType

    Debug.Print(GetType(Integer).GetType.ToString) 'Returns System.RuntimeType
    Debug.Print(GetType(Double).GetType.ToString) 'Returns System.RuntimeType
    Debug.Print(GetType(Object).GetType.ToString) 'Returns System.RuntimeType

    Debug.Print(MyValInt.GetType = GetType(Integer)) '# Returns True
    Debug.Print(MyValInt.GetType = GetType(Double)) 'Returns False
    Debug.Print(MyValInt.GetType = GetType(Object)) 'Returns False

    Debug.Print(MyValDble.GetType = GetType(Integer)) 'Returns False
    Debug.Print(MyValDble.GetType = GetType(Double)) '# Returns True
    Debug.Print(MyValDble.GetType = GetType(Object)) 'Returns False

    Debug.Print(MyObj.GetType = GetType(Integer)) 'Returns False
    Debug.Print(MyObj.GetType = GetType(Double)) '# Returns True
    Debug.Print(MyObj.GetType = GetType(Object)) 'Returns False

    Debug.Print(TypeOf MyObj Is Integer) 'Returns False
    Debug.Print(TypeOf MyObj Is Double) '# Returns True
    Debug.Print(TypeOf MyObj Is Object) '# Returns True


End Sub

EDIT

You can also use Information.TypeName(Object) to get the TypeName of a given object. For example,

Dim Foo as Bar
Dim Result as String
Result = TypeName(Foo)
Debug.Print(Result) 'Will display "Bar"

How to create correct JSONArray in Java using JSONObject

Here is some code using java 6 to get you started:

JSONObject jo = new JSONObject();
jo.put("firstName", "John");
jo.put("lastName", "Doe");

JSONArray ja = new JSONArray();
ja.put(jo);

JSONObject mainObj = new JSONObject();
mainObj.put("employees", ja);

Edit: Since there has been a lot of confusion about put vs add here I will attempt to explain the difference. In java 6 org.json.JSONArray contains the put method and in java 7 javax.json contains the add method.

An example of this using the builder pattern in java 7 looks something like this:

JsonObject jo = Json.createObjectBuilder()
  .add("employees", Json.createArrayBuilder()
    .add(Json.createObjectBuilder()
      .add("firstName", "John")
      .add("lastName", "Doe")))
  .build();

how to get the first and last days of a given month

$month = 10; // october

$firstday = date('01-' . $month . '-Y');
$lastday = date(date('t', strtotime($firstday)) .'-' . $month . '-Y');

How can I get relative path of the folders in my android project?

In Android, application-level meta data is accessed through the Context reference, which an activity is a descendant of.

For example, you can get the source directory via the getApplicationInfo().sourceDir property. There are methods for other folders as well (assets directory, data dir, database dir, etc.).

Correct way to import lodash

Import specific methods inside of curly brackets

import { map, tail, times, uniq } from 'lodash';

Pros:

  • Only one import line(for a decent amount of functions)
  • More readable usage: map() instead of _.map() later in the javascript code.

Cons:

  • Every time we want to use a new function or stop using another - it needs to be maintained and managed

Copied from:The Correct Way to Import Lodash Libraries - A Benchmark article written by Alexander Chertkov.

How do I format my oracle queries so the columns don't wrap?

I use a generic query I call "dump" (why? I don't know) that looks like this:

SET NEWPAGE NONE
SET PAGESIZE 0
SET SPACE 0
SET LINESIZE 16000
SET ECHO OFF
SET FEEDBACK OFF
SET VERIFY OFF
SET HEADING OFF
SET TERMOUT OFF
SET TRIMOUT ON
SET TRIMSPOOL ON
SET COLSEP |

spool &1..txt

@@&1

spool off
exit

I then call SQL*Plus passing the actual SQL script I want to run as an argument:

sqlplus -S user/password@database @dump.sql my_real_query.sql

The result is written to a file

my_real_query.sql.txt

.

Linq Syntax - Selecting multiple columns

You can use anonymous types for example:

  var empData = from res in _db.EMPLOYEEs
                where res.EMAIL == givenInfo || res.USER_NAME == givenInfo
                select new { res.EMAIL, res.USER_NAME };

Run an exe from C# code

Example:

Process process = Process.Start(@"Data\myApp.exe");
int id = process.Id;
Process tempProc = Process.GetProcessById(id);
this.Visible = false;
tempProc.WaitForExit();
this.Visible = true;

C# Example of AES256 encryption using System.Security.Cryptography.Aes

Maybe this example listed here can help you out. Statement from the author

about 24 lines of code to encrypt, 23 to decrypt

Due to the fact that the link in the original posting is dead - here the needed code parts (c&p without any change to the original source)

  /*
  Copyright (c) 2010 <a href="http://www.gutgames.com">James Craig</a>
  
  Permission is hereby granted, free of charge, to any person obtaining a copy
  of this software and associated documentation files (the "Software"), to deal
  in the Software without restriction, including without limitation the rights
  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  copies of the Software, and to permit persons to whom the Software is
  furnished to do so, subject to the following conditions:
  
  The above copyright notice and this permission notice shall be included in
  all copies or substantial portions of the Software.
  
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  THE SOFTWARE.*/
   
  #region Usings
  using System;
  using System.IO;
  using System.Security.Cryptography;
  using System.Text;
  #endregion
   
  namespace Utilities.Encryption
  {
      /// <summary>
      /// Utility class that handles encryption
      /// </summary>
      public static class AESEncryption
      {
          #region Static Functions
   
          /// <summary>
          /// Encrypts a string
          /// </summary>
          /// <param name="PlainText">Text to be encrypted</param>
          /// <param name="Password">Password to encrypt with</param>
          /// <param name="Salt">Salt to encrypt with</param>
          /// <param name="HashAlgorithm">Can be either SHA1 or MD5</param>
          /// <param name="PasswordIterations">Number of iterations to do</param>
          /// <param name="InitialVector">Needs to be 16 ASCII characters long</param>
          /// <param name="KeySize">Can be 128, 192, or 256</param>
          /// <returns>An encrypted string</returns>
          public static string Encrypt(string PlainText, string Password,
              string Salt = "Kosher", string HashAlgorithm = "SHA1",
              int PasswordIterations = 2, string InitialVector = "OFRna73m*aze01xY",
              int KeySize = 256)
          {
              if (string.IsNullOrEmpty(PlainText))
                  return "";
              byte[] InitialVectorBytes = Encoding.ASCII.GetBytes(InitialVector);
              byte[] SaltValueBytes = Encoding.ASCII.GetBytes(Salt);
              byte[] PlainTextBytes = Encoding.UTF8.GetBytes(PlainText);
              PasswordDeriveBytes DerivedPassword = new PasswordDeriveBytes(Password, SaltValueBytes, HashAlgorithm, PasswordIterations);
              byte[] KeyBytes = DerivedPassword.GetBytes(KeySize / 8);
              RijndaelManaged SymmetricKey = new RijndaelManaged();
              SymmetricKey.Mode = CipherMode.CBC;
              byte[] CipherTextBytes = null;
              using (ICryptoTransform Encryptor = SymmetricKey.CreateEncryptor(KeyBytes, InitialVectorBytes))
              {
                  using (MemoryStream MemStream = new MemoryStream())
                  {
                      using (CryptoStream CryptoStream = new CryptoStream(MemStream, Encryptor, CryptoStreamMode.Write))
                      {
                          CryptoStream.Write(PlainTextBytes, 0, PlainTextBytes.Length);
                          CryptoStream.FlushFinalBlock();
                          CipherTextBytes = MemStream.ToArray();
                          MemStream.Close();
                          CryptoStream.Close();
                      }
                  }
              }
              SymmetricKey.Clear();
              return Convert.ToBase64String(CipherTextBytes);
          }
   
          /// <summary>
          /// Decrypts a string
          /// </summary>
          /// <param name="CipherText">Text to be decrypted</param>
          /// <param name="Password">Password to decrypt with</param>
          /// <param name="Salt">Salt to decrypt with</param>
          /// <param name="HashAlgorithm">Can be either SHA1 or MD5</param>
          /// <param name="PasswordIterations">Number of iterations to do</param>
          /// <param name="InitialVector">Needs to be 16 ASCII characters long</param>
          /// <param name="KeySize">Can be 128, 192, or 256</param>
          /// <returns>A decrypted string</returns>
          public static string Decrypt(string CipherText, string Password,
              string Salt = "Kosher", string HashAlgorithm = "SHA1",
              int PasswordIterations = 2, string InitialVector = "OFRna73m*aze01xY",
              int KeySize = 256)
          {
              if (string.IsNullOrEmpty(CipherText))
                  return "";
              byte[] InitialVectorBytes = Encoding.ASCII.GetBytes(InitialVector);
              byte[] SaltValueBytes = Encoding.ASCII.GetBytes(Salt);
              byte[] CipherTextBytes = Convert.FromBase64String(CipherText);
              PasswordDeriveBytes DerivedPassword = new PasswordDeriveBytes(Password, SaltValueBytes, HashAlgorithm, PasswordIterations);
              byte[] KeyBytes = DerivedPassword.GetBytes(KeySize / 8);
              RijndaelManaged SymmetricKey = new RijndaelManaged();
              SymmetricKey.Mode = CipherMode.CBC;
              byte[] PlainTextBytes = new byte[CipherTextBytes.Length];
              int ByteCount = 0;
              using (ICryptoTransform Decryptor = SymmetricKey.CreateDecryptor(KeyBytes, InitialVectorBytes))
              {
                  using (MemoryStream MemStream = new MemoryStream(CipherTextBytes))
                  {
                      using (CryptoStream CryptoStream = new CryptoStream(MemStream, Decryptor, CryptoStreamMode.Read))
                      {
   
                          ByteCount = CryptoStream.Read(PlainTextBytes, 0, PlainTextBytes.Length);
                          MemStream.Close();
                          CryptoStream.Close();
                      }
                  }
              }
              SymmetricKey.Clear();
              return Encoding.UTF8.GetString(PlainTextBytes, 0, ByteCount);
          }
   
          #endregion
      }
  }

mysql datetime comparison

...this is obviously performing a 'string' comparison

No - if the date/time format matches the supported format, MySQL performs implicit conversion to convert the value to a DATETIME, based on the column it is being compared to. Same thing happens with:

WHERE int_column = '1'

...where the string value of "1" is converted to an INTeger because int_column's data type is INT, not CHAR/VARCHAR/TEXT.

If you want to explicitly convert the string to a DATETIME, the STR_TO_DATE function would be the best choice:

WHERE expires_at <= STR_TO_DATE('2010-10-15 10:00:00', '%Y-%m-%d %H:%i:%s')

Why does the JFrame setSize() method not set the size correctly?

I know that this question is about 6+ years old, but the answer by @Kyle doesn't work.

Using this

setSize(width - (getInsets().left + getInsets().right), height - (getInsets().top + getInsets().bottom));

But this always work in any size:

setSize(width + 14, height + 7);

If you don't want the border to border, and only want the white area, here:

setSize(width + 16, height + 39);

Also this only works on Windows 10, for MacOS users, use @ben's answer.

Is there a simple way to delete a list element by value?

You can do

a=[1,2,3,4]
if 6 in a:
    a.remove(6)

but above need to search 6 in list a 2 times, so try except would be faster

try:
    a.remove(6)
except:
    pass

SQL Joins Vs SQL Subqueries (Performance)?

I would EXPECT the first query to be quicker, mainly because you have an equivalence and an explicit JOIN. In my experience IN is a very slow operator, since SQL normally evaluates it as a series of WHERE clauses separated by "OR" (WHERE x=Y OR x=Z OR...).

As with ALL THINGS SQL though, your mileage may vary. The speed will depend a lot on indexes (do you have indexes on both ID columns? That will help a lot...) among other things.

The only REAL way to tell with 100% certainty which is faster is to turn on performance tracking (IO Statistics is especially useful) and run them both. Make sure to clear your cache between runs!

How to pass parameters to a partial view in ASP.NET MVC?

make sure you add {} around Html.RenderPartial, as:

@{Html.RenderPartial("FullName", new { firstName = model.FirstName, lastName = model.LastName});}

not

@Html.RenderPartial("FullName", new { firstName = model.FirstName, lastName = model.LastName});

Bootstrap Modal before form Submit

You can use browser default prompt window. Instead of basic <input type="submit" (...) > try:

<button onClick="if(confirm(\'are you sure ?\')){ this.form.submit() }">Save</button>

Python: Assign print output to a variable

The print statement in Python converts its arguments to strings, and outputs those strings to stdout. To save the string to a variable instead, only convert it to a string:

a = str(tag.getArtist())

How to make an Android Spinner with initial text "Select One"?

For those using Xamarin, here is the C# equivalent to aaronvargas's answer above.

using Android.Content;
using Android.Database;
using Android.Views;
using Android.Widget;
using Java.Lang;

namespace MyNamespace.Droid
{ 
  public class NothingSelectedSpinnerAdapter : BaseAdapter, ISpinnerAdapter, IListAdapter
  {
    protected static readonly int EXTRA = 1;
    protected ISpinnerAdapter adapter;
    protected Context context;
    protected int nothingSelectedLayout;
    protected int nothingSelectedDropdownLayout;
    protected LayoutInflater layoutInflater;

    public NothingSelectedSpinnerAdapter(ISpinnerAdapter spinnerAdapter, int nothingSelectedLayout, Context context) : this(spinnerAdapter, nothingSelectedLayout, -1, context)
    {
    }

    public NothingSelectedSpinnerAdapter(ISpinnerAdapter spinnerAdapter, int nothingSelectedLayout, int nothingSelectedDropdownLayout, Context context)
    {
      this.adapter = spinnerAdapter;
      this.context = context;
      this.nothingSelectedLayout = nothingSelectedLayout;
      this.nothingSelectedDropdownLayout = nothingSelectedDropdownLayout;
      layoutInflater = LayoutInflater.From(context);
    }

    protected View GetNothingSelectedView(ViewGroup parent)
    {
      return layoutInflater.Inflate(nothingSelectedLayout, parent, false);
    }

    protected View GetNothingSelectedDropdownView(ViewGroup parent)
    {
      return layoutInflater.Inflate(nothingSelectedDropdownLayout, parent, false);
    }

    public override Object GetItem(int position)
    {
      return position == 0 ? null : adapter.GetItem(position - EXTRA);
    }

    public override long GetItemId(int position)
    {
      return position >= EXTRA ? adapter.GetItemId(position - EXTRA) : position - EXTRA;
    }

    public override View GetView(int position, View convertView, ViewGroup parent)
    {
      // This provides the View for the Selected Item in the Spinner, not
      // the dropdown (unless dropdownView is not set).
      if (position == 0)
      {
        return GetNothingSelectedView(parent);
      }

      // Could re-use the convertView if possible.
      return this.adapter.GetView(position - EXTRA, null, parent);
    }

    public override int Count
    {
      get
      {
        int count = this.adapter.Count;
        return count == 0 ? 0 : count + EXTRA;
      }
    }

    public override View GetDropDownView(int position, View convertView, ViewGroup parent)
    {
      // Android BUG! http://code.google.com/p/android/issues/detail?id=17128 -
      // Spinner does not support multiple view types
      if (position == 0)
      {
        return nothingSelectedDropdownLayout == -1 ?
          new View(context) :
          GetNothingSelectedDropdownView(parent);
      }

      // Could re-use the convertView if possible, use setTag...
      return adapter.GetDropDownView(position - EXTRA, null, parent);
    }

    public override int GetItemViewType(int position)
    {
      return 0;
    }

    public override int ViewTypeCount => 1;

    public override bool HasStableIds => this.adapter.HasStableIds;

    public override bool IsEmpty => this.adapter.IsEmpty;

    public override void RegisterDataSetObserver(DataSetObserver observer)
    {
      adapter.RegisterDataSetObserver(observer);
    }

    public override void UnregisterDataSetObserver(DataSetObserver observer)
    {
      adapter.UnregisterDataSetObserver(observer);
    }

    public override bool AreAllItemsEnabled()
    {
      return false;
    }

    public override bool IsEnabled(int position)
    {
      return position > 0;
    }
  }
}

How to handle floats and decimal separators with html5 input type number

I think what's missing in the answers above is the need to specify a different value for the step attribute, which has a default value of 1. If you want the input's validation algorithm to allow floating-point values, specify a step accordingly.

For example, I wanted dollar amounts, so I specified a step like this:

 <input type="number" name="price"
           pattern="[0-9]+([\.,][0-9]+)?" step="0.01"
            title="This should be a number with up to 2 decimal places.">

There's nothing wrong with using jQuery to retrieve the value, but you will find it useful to use the DOM API directly to get the elements's validity.valid property.

I had a similar issue with the decimal point, but the reason I realized there was an issue was because of the styling that Twitter Bootstrap adds to a number input with an invalid value.

Here's a fiddle demonstrating that the adding of the step attribute makes it work, and also testing whether the current value is valid:

TL;DR: Set the a step attribute to a floating-point value, because it defaults to 1.

NOTE: The comma doesn't validate for me, but I suspect that if I set my OS language/region settings to somewhere that uses a comma as the decimal separator, it would work. *note in note*: that was not the case for OS language/keyboard settings *German* in Ubuntu/Gnome 14.04.

Rotating a two-dimensional array in Python

def ruota_orario(matrix):
   ruota=list(zip(*reversed(matrix)))
   return[list(elemento) for elemento in ruota]
def ruota_antiorario(matrix):
   ruota=list(zip(*reversed(matrix)))
   return[list(elemento)[::-1] for elemento in ruota][::-1]

Creating self signed certificate for domain and subdomains - NET::ERR_CERT_COMMON_NAME_INVALID

I think it may be a bug in chrome. There was a similar issue long back: See this.

Try in a different browser. I think it should work fine.

How to read and write INI file with Python3?

Use nested dictionaries. Take a look:

INI File: example.ini

[Section]
Key = Value

Code:

class IniOpen:
    def __init__(self, file):
        self.parse = {}
        self.file = file
        self.open = open(file, "r")
        self.f_read = self.open.read()
        split_content = self.f_read.split("\n")

        section = ""
        pairs = ""

        for i in range(len(split_content)):
            if split_content[i].find("[") != -1:
                section = split_content[i]
                section = string_between(section, "[", "]")  # define your own function
                self.parse.update({section: {}})
            elif split_content[i].find("[") == -1 and split_content[i].find("="):
                pairs = split_content[i]
                split_pairs = pairs.split("=")
                key = split_pairs[0].trim()
                value = split_pairs[1].trim()
                self.parse[section].update({key: value})

    def read(self, section, key):
        try:
            return self.parse[section][key]
        except KeyError:
            return "Sepcified Key Not Found!"

    def write(self, section, key, value):
        if self.parse.get(section) is  None:
            self.parse.update({section: {}})
        elif self.parse.get(section) is not None:
            if self.parse[section].get(key) is None:
                self.parse[section].update({key: value})
            elif self.parse[section].get(key) is not None:
                return "Content Already Exists"

Apply code like so:

ini_file = IniOpen("example.ini")
print(ini_file.parse) # prints the entire nested dictionary
print(ini_file.read("Section", "Key") # >> Returns Value
ini_file.write("NewSection", "NewKey", "New Value"

Detecting Windows or Linux?

apache commons lang has a class SystemUtils.java you can use :

SystemUtils.IS_OS_LINUX
SystemUtils.IS_OS_WINDOWS

What is the difference between ArrayList.clear() and ArrayList.removeAll()?

The time complexity of ArrayList.clear() is O(n) and of removeAll is O(n^2).

So yes, ArrayList.clear is much faster.

Creating JSON on the fly with JObject

Simple way of creating newtonsoft JObject from Properties.

This is a Sample User Properties

public class User
{
    public string Name;
    public string MobileNo;
    public string Address;
}

and i want this property in newtonsoft JObject is:

JObject obj = JObject.FromObject(new User()
{
    Name = "Manjunath",
    MobileNo = "9876543210",
    Address = "Mumbai, Maharashtra, India",
});

Output will be like this:

{"Name":"Manjunath","MobileNo":"9876543210","Address":"Mumbai, Maharashtra, India"}

C++ calling base class constructors

The default class constructor is called unless you explicitly call another constructor in the derived class. the language specifies this.

Rectangle(int h,int w):
   Shape(h,w)
  {...}

Will call the other base class constructor.

What is the difference between JSF, Servlet and JSP?

JSP stands for JAVA SERVER PAGE........ jsp is not a servlet. Jsp uses code and HTML tag both in itself you dont need to make a HTML and a servlet seprately.Jsp are playing magnificent role in web application. Servlet is a java class plays an role to make your HTML page from static to dynamic .

How to change progress bar's progress color in Android

Here is the code for changing the color of ProgressBar by programatically.

ProgressBar progressBar = (ProgressBar) findViewById(R.id.pb_listProgressBar);
int colorCodeDark = Color.parseColor("#F44336");
progressBar.setIndeterminateTintList(ColorStateList.valueOf(colorCodeDark));

Remove empty array elements

You can just do

array_filter($array)

array_filter: "If no callback is supplied, all entries of input equal to FALSE will be removed." This means that elements with values NULL, 0, '0', '', FALSE, array() will be removed too.

The other option is doing

array_diff($array, array(''))

which will remove elements with values NULL, '' and FALSE.

Hope this helps :)

UPDATE

Here is an example.

$a = array(0, '0', NULL, FALSE, '', array());

var_dump(array_filter($a));
// array()

var_dump(array_diff($a, array(0))) // 0 / '0'
// array(NULL, FALSE, '', array());

var_dump(array_diff($a, array(NULL))) // NULL / FALSE / ''
// array(0, '0', array())

To sum up:

  • 0 or '0' will remove 0 and '0'
  • NULL, FALSE or '' will remove NULL, FALSE and ''

Insert image after each list item

For IE8 support, the "content" property cannot be empty.

To get around this I've done the following :

.ul li:after {
    content:"icon";
    text-indent:-999em;
    display:block;
    width:32px;
    height:32px;
    background:url(../img/icons/spritesheet.png) 0 -620px no-repeat;
    margin:5% 0 0 45%;
}

Note : This works with image sprites too

List vs tuple, when to use each?

There's a strong culture of tuples being for heterogeneous collections, similar to what you'd use structs for in C, and lists being for homogeneous collections, similar to what you'd use arrays for. But I've never quite squared this with the mutability issue mentioned in the other answers. Mutability has teeth to it (you actually can't change a tuple), while homogeneity is not enforced, and so seems to be a much less interesting distinction.

How to trigger ngClick programmatically

The syntax is the following:

function clickOnUpload() {
  $timeout(function() {
    angular.element('#myselector').triggerHandler('click');
  });
};

// Using Angular Extend
angular.extend($scope, {
  clickOnUpload: clickOnUpload
});

// OR Using scope directly
$scope.clickOnUpload = clickOnUpload;

More info on Angular Extend way here.

If you are using old versions of angular, you should use trigger instead of triggerHandler.

If you need to apply stop propagation you can use this method as follows:

<a id="myselector" ng-click="clickOnUpload(); $event.stopPropagation();">
  Something
</a>

How to get ID of the last updated row in MySQL?

If you are only doing insertions, and want one from the same session, do as per peirix's answer. If you are doing modifications, you will need to modify your database schema to store which entry was most recently updated.

If you want the id from the last modification, which may have been from a different session (i.e. not the one that was just done by the PHP code running at present, but one done in response to a different request), you can add a TIMESTAMP column to your table called last_modified (see http://dev.mysql.com/doc/refman/5.1/en/datetime.html for information), and then when you update, set last_modified=CURRENT_TIME.

Having set this, you can then use a query like: SELECT id FROM table ORDER BY last_modified DESC LIMIT 1; to get the most recently modified row.

Can I hide/show asp:Menu items based on role?

You just have to remove the parent menu in the page init event.

    Protected Sub navMenu_Init(sender As Object, e As System.EventArgs) Handles navMenu.Init
    'Remove the admin menu for the norms
    Dim cUser As Boolean = HttpContext.Current.User.IsInRole("Admin")

    'If user is not in the Admin role removes the 1st menu at index 0
    If cUser = False Then
        navMenu.Items.RemoveAt(0)
    End If
End Sub

How to convert UTC timestamp to device local time in android

I have do something like this to get date in local device timezone from UTC time stamp.

private long UTC_TIMEZONE=1470960000;
private String OUTPUT_DATE_FORMATE="dd-MM-yyyy - hh:mm a"

getDateFromUTCTimestamp(UTC_TIMEZONE,OUTPUT_DATE_FORMATE);

Here is the function

 public String getDateFromUTCTimestamp(long mTimestamp, String mDateFormate) {
        String date = null;
        try {
            Calendar cal = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
            cal.setTimeInMillis(mTimestamp * 1000L);
            date = DateFormat.format(mDateFormate, cal.getTimeInMillis()).toString();

            SimpleDateFormat formatter = new SimpleDateFormat(mDateFormate);
            formatter.setTimeZone(TimeZone.getTimeZone("UTC"));
            Date value = formatter.parse(date);

            SimpleDateFormat dateFormatter = new SimpleDateFormat(mDateFormate);
            dateFormatter.setTimeZone(TimeZone.getDefault());
            date = dateFormatter.format(value);
            return date;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return date;
    }

Result :

12-08-2016 - 04:30 PM 

Hope this will work for others.

Visual Studio Code: format is not using indent settings

For myself, this problem was caused by using the prettier VSCode plugin without having a prettier config file in the workspace.

Disabling the plugin fixed the problem. It could have also probably been fixed by relying on the prettier config.

Android 1.6: "android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application"

As it's said, you need an Activity as context for the dialog, use "YourActivity.this" for a static context or check here for how to use a dynamic one in a safe mode

Selecting multiple columns in a Pandas dataframe

In the latest version of Pandas there is an easy way to do exactly this. Column names (which are strings) can be sliced in whatever manner you like.

columns = ['b', 'c']
df1 = pd.DataFrame(df, columns=columns)

Two statements next to curly brace in an equation

Or this:

f(x)=\begin{cases}
0, & -\pi\leqslant x <0\\
\pi, & 0 \leqslant x \leqslant +\pi
\end{cases}

How to completely uninstall python 2.7.13 on Ubuntu 16.04

try following to see all instances of python

whereis python
which python

Then remove all instances using:

sudo apt autoremove python

repeat sudo apt autoremove python(for all versions) that should do it, then install Anaconda and manage Pythons however you like if you need to reinstall it.

Random row selection in Pandas dataframe

Below line will randomly select n number of rows out of the total existing row numbers from the dataframe df without replacement.

df=df.take(np.random.permutation(len(df))[:n])

HttpServletRequest - Get query string parameters, no form data

As the other answers state there is no way getting query string parameters using servlet api.

So, I think the best way to get query parameters is parsing the query string yourself. ( It is more complicated iterating over parameters and checking if query string contains the parameter)

I wrote below code to get query string parameters. Using apache StringUtils and ArrayUtils which supports CSV separated query param values as well.

Example: username=james&username=smith&password=pwd1,pwd2 will return

password : [pwd1, pwd2] (length = 2)

username : [james, smith] (length = 2)

public static Map<String, String[]> getQueryParameters(HttpServletRequest request) throws UnsupportedEncodingException {
    Map<String, String[]> queryParameters = new HashMap<>();
    String queryString = request.getQueryString();
    if (StringUtils.isNotEmpty(queryString)) {
        queryString = URLDecoder.decode(queryString, StandardCharsets.UTF_8.toString());
        String[] parameters = queryString.split("&");
        for (String parameter : parameters) {
            String[] keyValuePair = parameter.split("=");
            String[] values = queryParameters.get(keyValuePair[0]);
            //length is one if no value is available.
            values = keyValuePair.length == 1 ? ArrayUtils.add(values, "") :
                    ArrayUtils.addAll(values, keyValuePair[1].split(",")); //handles CSV separated query param values.
            queryParameters.put(keyValuePair[0], values);
        }
    }
    return queryParameters;
}

Regular expression to find two strings anywhere in input

You can try:

\bcat\b.*\bmat\b

\b is an anchor and matches a word boundary. It will look for words cat and mat anywhere in the string with mat following cat. It will not match:

Therez caterpillar on the mat.

but will match

The cat slept on the mat in front of the fire

If you want to match strings which have letters cat followed by mat, you can try:

cat.*mat

This will match both the above example strings.

What is size_t in C?

From Wikipedia:

According to the 1999 ISO C standard (C99), size_t is an unsigned integer type of at least 16 bit (see sections 7.17 and 7.18.3).

size_tis an unsigned data type defined by several C/C++ standards, e.g. the C99 ISO/IEC 9899 standard, that is defined in stddef.h.1 It can be further imported by inclusion of stdlib.h as this file internally sub includes stddef.h.

This type is used to represent the size of an object. Library functions that take or return sizes expect them to be of type or have the return type of size_t. Further, the most frequently used compiler-based operator sizeof should evaluate to a constant value that is compatible with size_t.

As an implication, size_t is a type guaranteed to hold any array index.

mailto using javascript

No need for jQuery. And it isn't necessary to open a new window. Protocols which doesn't return HTTP data to the browser (mailto:, irc://, magnet:, ftp:// (<- it depends how it is implemented, normally the browser has an FTP client built in)) can be queried in the same window without losing the current content. In your case:

function redirect()
{
    window.location.href = "mailto:[email protected]";
}
<body onload="javascript: redirect();">

Or just directly

<body onload="javascript: window.location.href='mailto:[email protected]';">

Meaning of "[: too many arguments" error from if [] (square brackets)

I have had same problem with my scripts. But when I did some modifications it worked for me. I did like this :-

export k=$(date "+%k");
if [ $k -ge 16 ] 
    then exit 0; 
else 
    echo "good job for nothing"; 
fi;

that way I resolved my problem. Hope that will help for you too.

Transpose a matrix in Python

If we wanted to return the same matrix we would write:

return [[ m[row][col] for col in range(0,width) ] for row in range(0,height) ]

What this does is it iterates over a matrix m by going through each row and returning each element in each column. So the order would be like:

[[1,2,3],
[4,5,6],
[7,8,9]]

Now for question 3, we instead want to go column by column, returning each element in each row. So the order would be like:

[[1,4,7],
[2,5,8],
[3,6,9]]

Therefore just switch the order in which we iterate:

return [[ m[row][col] for row in range(0,height) ] for col in range(0,width) ]

JavaScript function in href vs. onclick

This works

<a href="#" id="sampleApp" onclick="myFunction(); return false;">Click Here</a>

How to put spacing between floating divs?

You can do the following:

Assuming your container div has a class "yellow".

.yellow div {
    // Apply margin to every child in this container
    margin: 10px;
}

.yellow div:first-child, .yellow div:nth-child(3n+1) {
    // Remove the margin on the left side on the very first and then every fourth element (for example)
    margin-left: 0;
}

.yellow div:last-child {
    // Remove the right side margin on the last element
    margin-right: 0;
}

The number 3n+1 equals every fourth element outputted and will clearly only work if you know how many will be displayed in a row, but it should illustrate the example. More details regarding nth-child here.

Note: For :first-child to work in IE8 and earlier, a <!DOCTYPE> must be declared.

Note2: The :nth-child() selector is supported in all major browsers, except IE8 and earlier.

How to move a marker in Google Maps API

use panTo(x,y).This will help u

Escaping backslash in string - javascript

I think this is closer to the answer you're looking for:

<input type="file">

$file = $(file);
var filename = fileElement[0].files[0].name;

HttpClient not supporting PostAsJsonAsync method C#

I know this reply is too late, I had the same issue and i was adding the System.Net.Http.Formatting.Extension Nuget, after checking here and there I found that the Nuget is added but the System.Net.Http.Formatting.dll was not added to the references, I just reinstalled the Nuget

Set keyboard caret position in html textbox

Excerpted from Josh Stodola's Setting keyboard caret Position in a Textbox or TextArea with Javascript

A generic function that will allow you to insert the caret at any position of a textbox or textarea that you wish:

function setCaretPosition(elemId, caretPos) {
    var elem = document.getElementById(elemId);

    if(elem != null) {
        if(elem.createTextRange) {
            var range = elem.createTextRange();
            range.move('character', caretPos);
            range.select();
        }
        else {
            if(elem.selectionStart) {
                elem.focus();
                elem.setSelectionRange(caretPos, caretPos);
            }
            else
                elem.focus();
        }
    }
}

The first expected parameter is the ID of the element you wish to insert the keyboard caret on. If the element is unable to be found, nothing will happen (obviously). The second parameter is the caret positon index. Zero will put the keyboard caret at the beginning. If you pass a number larger than the number of characters in the elements value, it will put the keyboard caret at the end.

Tested on IE6 and up, Firefox 2, Opera 8, Netscape 9, SeaMonkey, and Safari. Unfortunately on Safari it does not work in combination with the onfocus event).

An example of using the above function to force the keyboard caret to jump to the end of all textareas on the page when they receive focus:

function addLoadEvent(func) {
    if(typeof window.onload != 'function') {
        window.onload = func;
    }
    else {
        if(func) {
            var oldLoad = window.onload;

            window.onload = function() {
                if(oldLoad)
                        oldLoad();

                func();
            }
        }
    }
}

// The setCaretPosition function belongs right here!

function setTextAreasOnFocus() {
/***
 * This function will force the keyboard caret to be positioned
 * at the end of all textareas when they receive focus.
 */
    var textAreas = document.getElementsByTagName('textarea');

    for(var i = 0; i < textAreas.length; i++) {
        textAreas[i].onfocus = function() {
            setCaretPosition(this.id, this.value.length);
        }
    }

    textAreas = null;
}

addLoadEvent(setTextAreasOnFocus);

How can I get last characters of a string

Performance

Today 2020.12.31 I perform tests on MacOs HighSierra 10.13.6 on Chrome v87, Safari v13.1.2 and Firefox v84 for chosen solutions for getting last character case (last N letters case results, for clarity I present in separate answer).

Results

For all browsers

  • solutions D,E,F are quite-fast or fastest
  • solutions G,H are slowest

enter image description here

Details

I perform 2 tests cases:

  • when string has 10 chars - you can run it HERE
  • when string has 1M chars - you can run it HERE

Below snippet presents solutions A B C D E F G (my), H (my)

_x000D_
_x000D_
//https://stackoverflow.com/questions/5873810/how-can-i-get-last-characters-of-a-string

// https://stackoverflow.com/a/30916653/860099
function A(s) {
  return s.substr(-1)
}

// https://stackoverflow.com/a/5873890/860099
function B(s) {
  return s.substr(s.length - 1)
}

// https://stackoverflow.com/a/17489443/860099
function C(s) {
  return s.substring(s.length - 1, s.length);
}

// https://stackoverflow.com/a/50395190/860099
function D(s) {
  return s.slice(-1);
}

// https://stackoverflow.com/a/50374396/860099
function E(s) {  
  return s.charAt(s.length-1);
}

// https://stackoverflow.com/a/17489443/860099
function F(s) {  
  return s[s.length-1];
}

// my
function G(s) {
  return s.match(/.$/);
}

// my
function H(s) {
  return [...s].pop();
}

// --------------------
// TEST
// --------------------

[A,B,C,D,E,F,G,H].map(f=> {  
  console.log(
    f.name + ' ' + f('ctl03_Tabs1')
  )})
_x000D_
This shippet only presents functions used in performance tests - it not perform tests itself!
_x000D_
_x000D_
_x000D_

And here are example results for chrome

enter image description here

Save a subplot in matplotlib

Applying the full_extent() function in an answer by @Joe 3 years later from here, you can get exactly what the OP was looking for. Alternatively, you can use Axes.get_tightbbox() which gives a little tighter bounding box

import matplotlib.pyplot as plt
import matplotlib as mpl
import numpy as np
from matplotlib.transforms import Bbox

def full_extent(ax, pad=0.0):
    """Get the full extent of an axes, including axes labels, tick labels, and
    titles."""
    # For text objects, we need to draw the figure first, otherwise the extents
    # are undefined.
    ax.figure.canvas.draw()
    items = ax.get_xticklabels() + ax.get_yticklabels() 
#    items += [ax, ax.title, ax.xaxis.label, ax.yaxis.label]
    items += [ax, ax.title]
    bbox = Bbox.union([item.get_window_extent() for item in items])

    return bbox.expanded(1.0 + pad, 1.0 + pad)

# Make an example plot with two subplots...
fig = plt.figure()
ax1 = fig.add_subplot(2,1,1)
ax1.plot(range(10), 'b-')

ax2 = fig.add_subplot(2,1,2)
ax2.plot(range(20), 'r^')

# Save the full figure...
fig.savefig('full_figure.png')

# Save just the portion _inside_ the second axis's boundaries
extent = full_extent(ax2).transformed(fig.dpi_scale_trans.inverted())
# Alternatively,
# extent = ax.get_tightbbox(fig.canvas.renderer).transformed(fig.dpi_scale_trans.inverted())
fig.savefig('ax2_figure.png', bbox_inches=extent)

I'd post a pic but I lack the reputation points

Google Android USB Driver and ADB

instead of modifying adb_usb.ini file I made changes on the file android_winusb.inf under directory android-sdk\extras\google\usb_driver\ alone and it worked for the tablet MID Q88 but i copied both sections [Google.NTamd64] and [Google.NTx86]

;Google MID Q88
%SingleAdbInterface%        = USB_INSTALL, USB\VID_18D1&PID_0003&MI_01
%CompositeAdbInterface%     = USB_INSTALL, USB\VID_18D1&PID_0003&REV_0230&MI_01

List an Array of Strings in alphabetical order

You can use Arrays.sort() method. Here's the example,

import java.util.Arrays;

public class Test 
{
    public static void main(String[] args) 
    {
        String arrString[] = { "peter", "taylor", "brooke", "frederick", "cameron" };
        orderedGuests(arrString);
    }

    public static void orderedGuests(String[] hotel)
    {
        Arrays.sort(hotel);
        System.out.println(Arrays.toString(hotel));
    }
}

Output

[brooke, cameron, frederick, peter, taylor]

Spring cron expression for every day 1:01:am

One thing i've noticed is: spring CronTrigger is not cron. You may end up with 7 parameters in a valid cron expression (wich you can validate on cronmaker.com) and then spring not accept it. Most of cases you just delete the last parameter and everything works fine.

PDO's query vs execute

Gilean's answer is great, but I just wanted to add that sometimes there are rare exceptions to best practices, and you might want to test your environment both ways to see what will work best.

In one case, I found that query worked faster for my purposes because I was bulk transferring trusted data from an Ubuntu Linux box running PHP7 with the poorly supported Microsoft ODBC driver for MS SQL Server.

I arrived at this question because I had a long running script for an ETL that I was trying to squeeze for speed. It seemed intuitive to me that query could be faster than prepare & execute because it was calling only one function instead of two. The parameter binding operation provides excellent protection, but it might be expensive and possibly avoided if unnecessary.

Given a couple rare conditions:

  1. If you can't reuse a prepared statement because it's not supported by the Microsoft ODBC driver.

  2. If you're not worried about sanitizing input and simple escaping is acceptable. This may be the case because binding certain datatypes isn't supported by the Microsoft ODBC driver.

  3. PDO::lastInsertId is not supported by the Microsoft ODBC driver.

Here's a method I used to test my environment, and hopefully you can replicate it or something better in yours:

To start, I've created a basic table in Microsoft SQL Server

CREATE TABLE performancetest (
    sid INT IDENTITY PRIMARY KEY,
    id INT,
    val VARCHAR(100)
);

And now a basic timed test for performance metrics.

$logs = [];

$test = function (String $type, Int $count = 3000) use ($pdo, &$logs) {
    $start = microtime(true);
    $i = 0;
    while ($i < $count) {
        $sql = "INSERT INTO performancetest (id, val) OUTPUT INSERTED.sid VALUES ($i,'value $i')";
        if ($type === 'query') {
            $smt = $pdo->query($sql);
        } else {
            $smt = $pdo->prepare($sql);
            $smt ->execute();
        }
        $sid = $smt->fetch(PDO::FETCH_ASSOC)['sid'];
        $i++;
    }
    $total = (microtime(true) - $start);
    $logs[$type] []= $total;
    echo "$total $type\n";
};

$trials = 15;
$i = 0;
while ($i < $trials) {
    if (random_int(0,1) === 0) {
        $test('query');
    } else {
        $test('prepare');
    }
    $i++;
}

foreach ($logs as $type => $log) {
    $total = 0;
    foreach ($log as $record) {
        $total += $record;
    }
    $count = count($log);
    echo "($count) $type Average: ".$total/$count.PHP_EOL;
}

I've played with multiple different trial and counts in my specific environment, and consistently get between 20-30% faster results with query than prepare/execute

5.8128969669342 prepare
5.8688418865204 prepare
4.2948560714722 query
4.9533629417419 query
5.9051351547241 prepare
4.332102060318 query
5.9672858715057 prepare
5.0667371749878 query
3.8260300159454 query
4.0791549682617 query
4.3775160312653 query
3.6910600662231 query
5.2708210945129 prepare
6.2671611309052 prepare
7.3791449069977 prepare
(7) prepare Average: 6.0673267160143
(8) query Average: 4.3276024162769

I'm curious to see how this test compares in other environments, like MySQL.

Hidden features of Python

Python 2.x ignores commas if found after the last element of the sequence:

>>> a_tuple_for_instance = (0,1,2,3,)
>>> another_tuple = (0,1,2,3)
>>> a_tuple_for_instance == another_tuple
True

A trailing comma causes a single parenthesized element to be treated as a sequence:

>>> a_tuple_with_one_element = (8,)

Initializing a member array in constructor initializer

You want to init an array of ints in your constructor? Point it to a static array.

class C 
{
public:
    int *cArray;

};

C::C {
    static int c_init[]{1,2,3};
    cArray = c_init;
}

Ubuntu apt-get unable to fetch packages

Ran into issues like, while running sudo apt-get install python3-env on Ubuntu WSL:

Err:1 http://security.ubuntu.com/ubuntu xenial-security/universe amd64 python3.5-venv amd64 3.5.2-2ubuntu0~16.04.9 
404  Not Found [IP: 2001:67c:1360:8001::23 80]

Running

sudo apt-get update

fixed those issues.

How to fetch all Git branches

Just these three commands will get all the branches:

git clone --mirror repo.git  .git     (gets just .git  - bare repository)

git config --bool core.bare false

git reset --hard

Android list view inside a scroll view

The answer is simple and I am surprised it has yet to be answered here.

Use a Header View or/and Footer View on the list itself. Don't mix a ScrollView with a ListView or anything that can scroll. It's meant to be used with headers and footers :)

Essentially, take all the content above your ListView, put it in another .xml file as a layout and then in code inflate it and add it to the list as a header view.

i.e.

View header = getLayoutInflater().inflate(R.layout.header, null);
View footer = getLayoutInflater().inflate(R.layout.footer, null);
listView.addHeaderView(header);
listView.addFooterView(footer);

Spring RequestMapping for controllers that produce and consume JSON

The simple answer to your question is that there is no Annotation-Inheritance in Java. However, there is a way to use the Spring annotations in a way that I think will help solve your problem.

@RequestMapping is supported at both the type level and at the method level.

When you put @RequestMapping at the type level, most of the attributes are 'inherited' for each method in that class. This is mentioned in the Spring reference documentation. Look at the api docs for details on how each attribute is handled when adding @RequestMapping to a type. I've summarized this for each attribute below:

  • name: Value at Type level is concatenated with value at method level using '#' as a separator.
  • value: Value at Type level is inherited by method.
  • path: Value at Type level is inherited by method.
  • method: Value at Type level is inherited by method.
  • params: Value at Type level is inherited by method.
  • headers: Value at Type level is inherited by method.
  • consumes: Value at Type level is overridden by method.
  • produces: Value at Type level is overridden by method.

Here is a brief example Controller that showcases how you could use this:

package com.example;

import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping(path = "/", 
        consumes = MediaType.APPLICATION_JSON_VALUE, 
        produces = MediaType.APPLICATION_JSON_VALUE, 
        method = {RequestMethod.GET, RequestMethod.POST})
public class JsonProducingEndpoint {

    private FooService fooService;

    @RequestMapping(path = "/foo", method = RequestMethod.POST)
    public String postAFoo(@RequestBody ThisIsAFoo theFoo) {
        fooService.saveTheFoo(theFoo);
        return "http://myservice.com/foo/1";
    }

    @RequestMapping(path = "/foo/{id}", method = RequestMethod.GET)
    public ThisIsAFoo getAFoo(@PathVariable String id) {
        ThisIsAFoo foo = fooService.getAFoo(id);
        return foo;
    }

    @RequestMapping(path = "/foo/{id}", produces = MediaType.APPLICATION_XML_VALUE, method = RequestMethod.GET)
    public ThisIsAFooXML getAFooXml(@PathVariable String id) {
        ThisIsAFooXML foo = fooService.getAFoo(id);
        return foo;
    }
}

Convert String To date in PHP

Try this:

$new_date=date('d-m-Y', strtotime($date));

Heroku deployment error H10 (App crashed)

I had the same issue (same error on heroku, working on local machine) and I tried all the solutions listed here including heroku run rails console which ran without error messages. I tried heroku run rake db:migrate and heroku run rake db:migrate:reset a few times. None of this solved the problem. On going through some files that are used in production but not in dev environment, I found some whitespace in the puma.rb file to be the culprit. Hope this helps someone who has the same issue. Changing this made it work

  ActiveRecord::Base.establish_connection
  End

to

  ActiveRecord::Base.establish_connection
end

What's the best practice for primary keys in tables?

I avoid using natural keys for one simple reason -- human error. Although natural unique identifiers are often available (SSN, VIN, Account Number, etc.), they require a human to enter them correctly. If you're using SSNs as a primary key, someone transposes a couple of numbers during data entry, and the error isn't discovered immediately, then you're faced with changing your primary key.

My primary keys are all handled by the database program in the background and the user is never aware of them.

Terminal Multiplexer for Microsoft Windows - Installers for GNU Screen or tmux

Look. This is way old, but on the off chance that someone from Google finds this, absolutely the best solution to this - (and it is AWESOME) - is to use ConEmu (or a package that includes and is built on top of ConEmu called cmder) and then either use plink or putty itself to connect to a specific machine, or, even better, set up a development environment as a local VM using Vagrant.

This is the only way I can ever see myself developing from a Windows box again.

I am confident enough to say that every other answer - while not necessarily bad answers - offer garbage solutions compared to this.

Update: As Of 1/8/2020 not all other solutions are garbage - Windows Terminal is getting there and WSL exists.

How do I get an element to scroll into view, using jQuery?

Simple 2 steps for scrolling down to end or bottom.

Step1: get the full height of scrollable(conversation) div.

Step2: apply scrollTop on that scrollable(conversation) div using the value obtained in step1.

var fullHeight = $('#conversation')[0].scrollHeight;

$('#conversation').scrollTop(fullHeight);

Above steps must be applied for every append on the conversation div.

How do I fix a compilation error for unhandled exception on call to Thread.sleep()?

Thread.sleep can throw an InterruptedException which is a checked exception. All checked exceptions must either be caught and handled or else you must declare that your method can throw it. You need to do this whether or not the exception actually will be thrown. Not declaring a checked exception that your method can throw is a compile error.

You either need to catch it:

try {
    Thread.sleep(1000);
} catch (InterruptedException e) {
    e.printStackTrace();
    // handle the exception...        
    // For example consider calling Thread.currentThread().interrupt(); here.
}

Or declare that your method can throw an InterruptedException:

public static void main(String[]args) throws InterruptedException

Related

How to properly and completely close/reset a TcpClient connection?

Closes a socket connection and allows for re-use of the socket:

tcpClient.Client.Disconnect(false);

List comprehension vs map

I tried the code by @alex-martelli but found some discrepancies

python -mtimeit -s "xs=range(123456)" "map(hex, xs)"
1000000 loops, best of 5: 218 nsec per loop
python -mtimeit -s "xs=range(123456)" "[hex(x) for x in xs]"
10 loops, best of 5: 19.4 msec per loop

map takes the same amount of time even for very large ranges while using list comprehension takes a lot of time as is evident from my code. So apart from being considered "unpythonic", I have not faced any performance issues relating to usage of map.

How to clear the logs properly for a Docker container?

To remove/clear docker container logs we can use below command

$(docker inspect container_id|grep "LogPath"|cut -d """ -f4) or $(docker inspect container_name|grep "LogPath"|cut -d """ -f4)

form serialize javascript (no framework)

The miniature from-serialize library doesn't rely on a framework. Other than something like that, you'll need to implement the serialization function yourself. (though at a weight of 1.2 kilobytes, why not use it?)

How to trim whitespace from a Bash variable?

You can trim simply with echo:

foo=" qsdqsd qsdqs q qs   "

# Not trimmed
echo \'$foo\'

# Trim
foo=`echo $foo`

# Trimmed
echo \'$foo\'

Setting width as a percentage using jQuery

Hemnath

If your variable is the percentage:

var myWidth = 70;
$('div#somediv').width(myWidth + '%');

If your variable is in pixels, and you want the percentage it take up of the parent:

var myWidth = 140;
var myPercentage = (myWidth / $('div#somediv').parent().width()) * 100;
$('div#somediv').width(myPercentage + '%');

Maximum Java heap size of a 32-bit JVM on a 64-bit OS

On Solaris the limit has been about 3.5 GB since Solaris 2.5. (about 10 years ago)

How do I write outputs to the Log in Android?

Please see the logs as this way,

Log.e("ApiUrl = ", "MyApiUrl") (error)
Log.w("ApiUrl = ", "MyApiUrl") (warning)
Log.i("ApiUrl = ", "MyApiUrl") (information)
Log.d("ApiUrl = ", "MyApiUrl") (debug)
Log.v("ApiUrl = ", "MyApiUrl") (verbose)

Get the index of a certain value in an array in PHP

$find="Topsite";
$list=array("Tope","Ajayi","Topsite","Infotech");
$list_count=count($list);
sort($list);
for($i=0;$i<$list_count;$i++)
{
    if($list[$i]==$find){
         $position=$i;
    }

}
echo $position;

Python csv string to array

Simple - the csv module works with lists, too:

>>> a=["1,2,3","4,5,6"]  # or a = "1,2,3\n4,5,6".split('\n')
>>> import csv
>>> x = csv.reader(a)
>>> list(x)
[['1', '2', '3'], ['4', '5', '6']]

When to use virtual destructors?

Virtual destructors are useful when you might potentially delete an instance of a derived class through a pointer to base class:

class Base 
{
    // some virtual methods
};

class Derived : public Base
{
    ~Derived()
    {
        // Do some important cleanup
    }
};

Here, you'll notice that I didn't declare Base's destructor to be virtual. Now, let's have a look at the following snippet:

Base *b = new Derived();
// use b
delete b; // Here's the problem!

Since Base's destructor is not virtual and b is a Base* pointing to a Derived object, delete b has undefined behaviour:

[In delete b], if the static type of the object to be deleted is different from its dynamic type, the static type shall be a base class of the dynamic type of the object to be deleted and the static type shall have a virtual destructor or the behavior is undefined.

In most implementations, the call to the destructor will be resolved like any non-virtual code, meaning that the destructor of the base class will be called but not the one of the derived class, resulting in a resources leak.

To sum up, always make base classes' destructors virtual when they're meant to be manipulated polymorphically.

If you want to prevent the deletion of an instance through a base class pointer, you can make the base class destructor protected and nonvirtual; by doing so, the compiler won't let you call delete on a base class pointer.

You can learn more about virtuality and virtual base class destructor in this article from Herb Sutter.

How to increase Heap size of JVM

Following are few options available to change Heap Size.

-Xms<size>        set initial Java heap size
-Xmx<size>        set maximum Java heap size
-Xss<size>        set java thread stack size


java -Xmx256m TestData.java

Difference between Math.Floor() and Math.Truncate()

Math.Floor(): Returns the largest integer less than or equal to the specified double-precision floating-point number.

Math.Round(): Rounds a value to the nearest integer or to the specified number of fractional digits.

Oracle: SQL select date with timestamp

You can specify the whole day by doing a range, like so:

WHERE bk_date >= TO_DATE('2012-03-18', 'YYYY-MM-DD')
AND bk_date <  TO_DATE('2012-03-19', 'YYYY-MM-DD')

More simply you can use TRUNC:

WHERE TRUNC(bk_date) = TO_DATE('2012-03-18', 'YYYY-MM-DD')

TRUNC without parameter removes hours, minutes and seconds from a DATE.

PHP fwrite new line

You append a newline to both the username and the password, i.e. the output would be something like

Sebastian
password
John
hfsjaijn

use fwrite($fh,$user." ".$password."\n"); instead to have them both on one line.
Or use fputcsv() to write the data and fgetcsv() to fetch it. This way you would at least avoid encoding problems like e.g. with $username='Charles, III';

...i.e. setting aside all the things that are wrong about storing plain passwords in plain files and using _GET for this type of operation (use _POST instead) ;-)

Adding script tag to React/JSX

You can also use react helmet

import React from "react";
import {Helmet} from "react-helmet";

class Application extends React.Component {
  render () {
    return (
        <div className="application">
            <Helmet>
                <meta charSet="utf-8" />
                <title>My Title</title>
                <link rel="canonical" href="http://example.com/example" />
                <script src="/path/to/resource.js" type="text/javascript" />
            </Helmet>
            ...
        </div>
    );
  }
};

Helmet takes plain HTML tags and outputs plain HTML tags. It's dead simple, and React beginner friendly.

How can I validate a string to only allow alphanumeric characters in it?

While I think the regex-based solution is probably the way I'd go, I'd be tempted to encapsulate this in a type.

public class AlphaNumericString
{
    public AlphaNumericString(string s)
    {
        Regex r = new Regex("^[a-zA-Z0-9]*$");
        if (r.IsMatch(s))
        {
            value = s;                
        }
        else
        {
            throw new ArgumentException("Only alphanumeric characters may be used");
        }
    }

    private string value;
    static public implicit operator string(AlphaNumericString s)
    {
        return s.value;
    }
}

Now, when you need a validated string, you can have the method signature require an AlphaNumericString, and know that if you get one, it is valid (apart from nulls). If someone attempts to pass in a non-validated string, it will generate a compiler error.

You can get fancier and implement all of the equality operators, or an explicit cast to AlphaNumericString from plain ol' string, if you care.

Inserting into Oracle and retrieving the generated sequence ID

Expanding a bit on the answers from @Guru and @Ronnis, you can hide the sequence and make it look more like an auto-increment using a trigger, and have a procedure that does the insert for you and returns the generated ID as an out parameter.

create table batch(batchid number,
    batchname varchar2(30),
    batchtype char(1),
    source char(1),
    intarea number)
/

create sequence batch_seq start with 1
/

create trigger batch_bi
before insert on batch
for each row
begin
    select batch_seq.nextval into :new.batchid from dual;
end;
/

create procedure insert_batch(v_batchname batch.batchname%TYPE,
    v_batchtype batch.batchtype%TYPE,
    v_source batch.source%TYPE,
    v_intarea batch.intarea%TYPE,
    v_batchid out batch.batchid%TYPE)
as
begin
    insert into batch(batchname, batchtype, source, intarea)
    values(v_batchname, v_batchtype, v_source, v_intarea)
    returning batchid into v_batchid;
end;
/

You can then call the procedure instead of doing a plain insert, e.g. from an anoymous block:

declare
    l_batchid batch.batchid%TYPE;
begin
    insert_batch(v_batchname => 'Batch 1',
        v_batchtype => 'A',
        v_source => 'Z',
        v_intarea => 1,
        v_batchid => l_batchid);
    dbms_output.put_line('Generated id: ' || l_batchid);

    insert_batch(v_batchname => 'Batch 99',
        v_batchtype => 'B',
        v_source => 'Y',
        v_intarea => 9,
        v_batchid => l_batchid);
    dbms_output.put_line('Generated id: ' || l_batchid);
end;
/

Generated id: 1
Generated id: 2

You can make the call without an explicit anonymous block, e.g. from SQL*Plus:

variable l_batchid number;
exec insert_batch('Batch 21', 'C', 'X', 7, :l_batchid);

... and use the bind variable :l_batchid to refer to the generated value afterwards:

print l_batchid;
insert into some_table values(:l_batch_id, ...);

Open file in a relative location in Python

This code works fine:

import os


def readFile(filename):
    filehandle = open(filename)
    print filehandle.read()
    filehandle.close()



fileDir = os.path.dirname(os.path.realpath('__file__'))
print fileDir

#For accessing the file in the same folder
filename = "same.txt"
readFile(filename)

#For accessing the file in a folder contained in the current folder
filename = os.path.join(fileDir, 'Folder1.1/same.txt')
readFile(filename)

#For accessing the file in the parent folder of the current folder
filename = os.path.join(fileDir, '../same.txt')
readFile(filename)

#For accessing the file inside a sibling folder.
filename = os.path.join(fileDir, '../Folder2/same.txt')
filename = os.path.abspath(os.path.realpath(filename))
print filename
readFile(filename)

Getting char from string at specified index

char = split_string_to_char(text)(index)

------

Function split_string_to_char(text) As String()

   Dim chars() As String
   For char_count = 1 To Len(text)
      ReDim Preserve chars(char_count - 1)
      chars(char_count - 1) = Mid(text, char_count, 1)
   Next
   split_string_to_char = chars
End Function

How to set JAVA_HOME path on Ubuntu?

add JAVA_HOME to the file:

/etc/environment

for it to be available to the entire system (you would need to restart Ubuntu though)

MATLAB - multiple return values from a function?

Matlab allows you to return multiple values as well as receive them inline.

When you call it, receive individual variables inline:

[array, listp, freep] = initialize(size)

How to listen for a WebView finishing loading a URL?

I found one elegant solution as well, have not tested it rigorously though:

public void onPageFinished(WebView view, String url) {
            super.onPageFinished(view, url);
            if (m_webView.getProgress() == 100) {
                progressBar.setVisibility(View.GONE);
                m_webView.setVisibility(View.VISIBLE);
            }
        } 

When do I have to use interfaces instead of abstract classes?

From The Java™ Tutorials - Abstract Classes Compared to Interfaces

Which should you use, abstract classes or interfaces?

  • Consider using abstract classes if any of these statements apply to your situation:
    • You want to share code among several closely related classes.
    • You expect that classes that extend your abstract class have many common methods or fields, or require access modifiers other than public (such as protected and private).
    • You want to declare non-static or non-final fields. This enables you to define methods that can access and modify the state of the object to which they belong.
  • Consider using interfaces if any of these statements apply to your situation:
    • You expect that unrelated classes would implement your interface. For example, the interfaces Comparable and Cloneable are implemented by many unrelated classes.
    • You want to specify the behavior of a particular data type, but not concerned about who implements its behavior.
    • You want to take advantage of multiple inheritance of type.

An example of an abstract class in the JDK is AbstractMap, which is part of the Collections Framework. Its subclasses (which include HashMap, TreeMap, and ConcurrentHashMap) share many methods (including get, put, isEmpty, containsKey, and containsValue) that AbstractMap defines.

AngularJS : ng-click not working

It just happend to me. I solved the problem by tracing backward from the point ng-click is coded. Found out that an extra

</div> 

was placed in the html to prematurely close the div block that contains the ng-click.

Removed the extra

</div> 

then everything is working fine.

Stopping a CSS3 Animation on last frame

-webkit-animation-fill-mode: forwards; /* Safari 4.0 - 8.0 */
animation-fill-mode: forwards;

Browser Support

  • Chrome 43.0 (4.0 -webkit-)
  • IE 10.0
  • Mozilla 16.0 ( 5.0 -moz-)
  • Shafari 4.0 -webkit-
  • Opera 15.0 -webkit- (12.112.0 -o-)

Usage:-

.fadeIn {
  animation-name: fadeIn;
    -webkit-animation-name: fadeIn;

    animation-duration: 1.5s;
    -webkit-animation-duration: 1.5s;

    animation-timing-function: ease;
    -webkit-animation-timing-function: ease;

     animation-fill-mode: forwards;
    -webkit-animation-fill-mode: forwards;
}


@keyframes fadeIn {
  from {
    opacity: 0;
  }

  to {
    opacity: 1;
  }
}

@-webkit-keyframes fadeIn {
  from {
    opacity: 0;
  }

  to {
    opacity: 1;
  }
}

Get the position of a div/span tag

You can call the method getBoundingClientRect() on a reference to the element. Then you can examine the top, left, right and/or bottom properties...

var offsets = document.getElementById('11a').getBoundingClientRect();
var top = offsets.top;
var left = offsets.left;

If using jQuery, you can use the more succinct code...

var offsets = $('#11a').offset();
var top = offsets.top;
var left = offsets.left;

C# refresh DataGridView when updating or inserted on another form

for refresh data gridview in any where you just need this code:

datagridview1.DataSource = "your DataSource";
datagridview1.Refresh();

How to get HTTP Response Code using Selenium WebDriver

You could try Mobilenium (https://github.com/rafpyprog/Mobilenium), a python package that binds BrowserMob Proxy and Selenium.

An usage example:

>>> from mobilenium import mobidriver
>>>
>>> browsermob_path = 'path/to/browsermob-proxy'
>>> mob = mobidriver.Firefox(browsermob_binary=browsermob_path)
>>> mob.get('http://python-requests.org')
301
>>> mob.response['redirectURL']
'http://docs.python-requests.org'
>>> mob.headers['Content-Type']
'application/json; charset=utf8'
>>> mob.title
'Requests: HTTP for Humans \u2014 Requests 2.13.0 documentation'
>>> mob.find_elements_by_tag_name('strong')[1].text
'Behold, the power of Requests'

Can I delete a git commit but keep the changes?

Using git 2.9 (precisely 2.9.2.windows.1) git reset HEAD^ prompts for more; not sure what is expected input here. Please refer below screenshot

enter image description here

Found other solution git reset HEAD~#numberOfCommits using which we can choose to select number of local commits you want to reset by keeping your changes intact. Hence, we get an opportunity to throw away all local commits as well as limited number of local commits.

Refer below screenshots showing git reset HEAD~1 in action: enter image description here

enter image description here

scikit-learn random state in splitting dataset

For multiple times of execution of our model, random state make sure that data values will be same for training and testing data sets. It fixes the order of data for train_test_split

What is token-based authentication?

From Auth0.com

Token-Based Authentication, relies on a signed token that is sent to the server on each request.

What are the benefits of using a token-based approach?

  • Cross-domain / CORS: cookies + CORS don't play well across different domains. A token-based approach allows you to make AJAX calls to any server, on any domain because you use an HTTP header to transmit the user information.

  • Stateless (a.k.a. Server side scalability): there is no need to keep a session store, the token is a self-contained entity that conveys all the user information. The rest of the state lives in cookies or local storage on the client side.

  • CDN: you can serve all the assets of your app from a CDN (e.g. javascript, HTML, images, etc.), and your server side is just the API.

  • Decoupling: you are not tied to any particular authentication scheme. The token might be generated anywhere, hence your API can be called from anywhere with a single way of authenticating those calls.

  • Mobile ready: when you start working on a native platform (iOS, Android, Windows 8, etc.) cookies are not ideal when consuming a token-based approach simplifies this a lot.

  • CSRF: since you are not relying on cookies, you don't need to protect against cross site requests (e.g. it would not be possible to sib your site, generate a POST request and re-use the existing authentication cookie because there will be none).

  • Performance: we are not presenting any hard perf benchmarks here, but a network roundtrip (e.g. finding a session on database) is likely to take more time than calculating an HMACSHA256 to validate a token and parsing its contents.

The right way of setting <a href=""> when it's a local file

By definition, file: URLs are system-dependent, and they have little use. A URL as in your example works when used locally, i.e. the linking page itself is in the user’s computer. But browsers generally refuse to follow file: links on a page that it has fetched with the HTTP protocol, so that the page's own URL is an http: URL. When you click on such a link, nothing happens. The purpose is presumably security: to prevent a remote page from accessing files in the visitor’s computer. (I think this feature was first implemented in Mozilla, then copied to other browsers.)

So if you work with HTML documents in your computer, the file: URLs should work, though there are system-dependent issues in their syntax (how you write path names and file names in such a URL).

If you really need to work with an HTML document on your computers and another HTML document on a web server, the way to make links work is to use the local file as primary and, if needed, use client-side scripting to fetch the document from the server,

How to make (link)button function as hyperlink?

This can be done very easily using a PostBackUrl and a regular button.

<asp:Button ID="Button1" runat="server" Text="Name of web location" PostBackUrl="web address" />

Hide/Show Column in an HTML Table

I would like to do this without attaching a class to every td

Personally, I would go with the the class-on-each-td/th/col approach. Then you can switch columns on and off using a single write to className on the container, assuming style rules like:

table.hide1 .col1 { display: none; }
table.hide2 .col2 { display: none; }
...

This is going to be faster than any JS loop approach; for really long tables it can make a significant difference to responsiveness.

If you can get away with not supporting IE6, you could use adjacency selectors to avoid having to add the class attributes to tds. Or alternatively, if your concern is making the markup cleaner, you could add them from JavaScript automatically in an initialisation step.

Why so red? IntelliJ seems to think every declaration/method cannot be found/resolved

For 2020.1.4 Ultimate edition, I had to do the following

View -> Maven -> Generate Sources and Update Folders For all Projects

The issue for me was the libraries were not getting populated with mvn -U clean install from the terminal.

enter image description here

What is AndroidX?

Just some bits addition from my side to all available answers

Need of AndroidX

  1. As said in amazing answer by @KhemRaj,

With the current naming convention, it isn’t clear which packages are bundled with the Android operating system, and which are packaged with your application’s APK (Android Package Kit). To clear up this confusion, all the unbundled libraries will be moved to AndroidX’s androidx.* namespace, while the android.* package hierarchy will be reserved for packages that ship with the Android operating system.

  1. Other than this,

    Initially, the name of each package indicated the minimum API level supported by that package, for example support-v4. However, version 26.0.0 of the Support Library increased the minimum API to 14, so today many of the package names have nothing to do with the minimum supported API level. When support-v4 and the support-v7 packages both have a minimum API of 14, it’s easy to see why people get confused!. So now with AndroidX, there is no dependence on the API level.

Another important change is that the AndroidX artifacts will update independently, so you’ll be able to update individual AndroidX libraries in your project, rather than having to change every dependency at once. Those frustrating “All com.android.support libraries must use the exact same version specification” messages should become a thing of the past!

xlsxwriter: is there a way to open an existing worksheet in my workbook?

You can use the workbook.get_worksheet_by_name() feature: https://xlsxwriter.readthedocs.io/workbook.html#get_worksheet_by_name

According to https://xlsxwriter.readthedocs.io/changes.html the feature has been added on May 13, 2016.

"Release 0.8.7 - May 13 2016

-Fix for issue when inserting read-only images on Windows. Issue #352.

-Added get_worksheet_by_name() method to allow the retrieval of a worksheet from a workbook via its name.

-Fixed issue where internal file creation and modification dates were in the local timezone instead of UTC."

How to calculate moving average without keeping the count and data-total?

New average = old average * (n-1)/n + new value /n

This is assuming the count only changed by one value. In case it is changed by M values then:

new average = old average * (n-len(M))/n + (sum of values in M)/n).

This is the mathematical formula (I believe the most efficient one), believe you can do further code by yourselves

how to replace characters in hive?

You can also use translate(). If the third argument is too short, the corresponding characters from the second argument are deleted. Unlike regexp_replace() you don't need to worry about special characters. Source code.

https://cwiki.apache.org/confluence/display/Hive/LanguageManual+UDF#LanguageManualUDF-StringFunctions

How to search contents of multiple pdf files?

First convert all your pdf files to text files:

for file in *.pdf;do pdftotext "$file"; done

Then use grep as normal. This is especially good as it is fast when you have multiple queries and a lot of PDF files.

What is the "right" JSON date format?

The prefered way is using 2018-04-23T18:25:43.511Z...

The picture below shows why this is the prefered way:

JSON Date

So as you see Date has a native Method toJSON, which return in this format and can be easily converted to Date again...

fastest way to export blobs from table into individual files

For me what worked by combining all the posts I have read is:

1.Enable OLE automation - if not enabled

sp_configure 'show advanced options', 1;  
GO  
RECONFIGURE;  
GO  
sp_configure 'Ole Automation Procedures', 1;  
GO  
RECONFIGURE;  
GO

2.Create a folder where the generated files will be stored:

C:\GREGTESTING

3.Create DocTable that will be used for file generation and store there the blobs in Doc_Content
enter image description here

CREATE TABLE [dbo].[Document](
    [Doc_Num] [numeric](18, 0) IDENTITY(1,1) NOT NULL,
    [Extension] [varchar](50) NULL,
    [FileName] [varchar](200) NULL,
    [Doc_Content] [varbinary](max) NULL   
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY] 

INSERT [dbo].[Document] ([Extension] ,[FileName] , [Doc_Content] )
    SELECT 'pdf', 'SHTP Notional hire - January 2019.pdf', 0x....(varbinary blob)

Important note!

Don't forget to add in Doc_Content column the varbinary of file you want to generate!

4.Run the below script

DECLARE @outPutPath varchar(50) = 'C:\GREGTESTING'
, @i bigint
, @init int
, @data varbinary(max) 
, @fPath varchar(max)  
, @folderPath  varchar(max)

--Get Data into temp Table variable so that we can iterate over it 
DECLARE @Doctable TABLE (id int identity(1,1), [Doc_Num]  varchar(100) , [FileName]  varchar(100), [Doc_Content] varBinary(max) )



INSERT INTO @Doctable([Doc_Num] , [FileName],[Doc_Content])
Select [Doc_Num] , [FileName],[Doc_Content] FROM  [dbo].[Document]



SELECT @i = COUNT(1) FROM @Doctable   

WHILE @i >= 1   

BEGIN    

SELECT 
    @data = [Doc_Content],
    @fPath = @outPutPath + '\' + [Doc_Num] +'_' +[FileName],
    @folderPath = @outPutPath + '\'+ [Doc_Num]
FROM @Doctable WHERE id = @i

EXEC sp_OACreate 'ADODB.Stream', @init OUTPUT; -- An instace created
EXEC sp_OASetProperty @init, 'Type', 1;  
EXEC sp_OAMethod @init, 'Open'; -- Calling a method
EXEC sp_OAMethod @init, 'Write', NULL, @data; -- Calling a method
EXEC sp_OAMethod @init, 'SaveToFile', NULL, @fPath, 2; -- Calling a method
EXEC sp_OAMethod @init, 'Close'; -- Calling a method
EXEC sp_OADestroy @init; -- Closed the resources
print 'Document Generated at - '+  @fPath   

--Reset the variables for next use
SELECT @data = NULL  
, @init = NULL
, @fPath = NULL  
, @folderPath = NULL
SET @i -= 1
END   

5.The results is shown below: enter image description here

WPF Data Binding and Validation Rules Best Practices

If your business class is directly used by your UI is preferrable to use IDataErrorInfo because it put logic closer to their owner.

If your business class is a stub class created by a reference to an WCF/XmlWeb service then you can not/must not use IDataErrorInfo nor throw Exception for use with ExceptionValidationRule. Instead you can:

  • Use custom ValidationRule.
  • Define a partial class in your WPF UI project and implements IDataErrorInfo.

How to place Text and an Image next to each other in HTML?

You want to use css float for this, you can put it directly in your code.

<body>
<img src="website_art.png" height= "75" width="235" style="float:left;"/>
<h3 style="float:right;">The Art of Gaming</h3>
</body>

But I would really suggest learning the basics of css and splitting all your styling out to a separate style sheet, and use classes. It will help you in the future. A good place to start is w3schools or, perhaps later down the path, Mozzila Dev. Network (MDN).

HTML:

<body>
  <img src="website_art.png" class="myImage"/>
  <h3 class="heading">The Art of Gaming</h3>
</body>

CSS:

.myImage {
  float: left;
  height: 75px;
  width: 235px;
  font-family: Veranda;
}
.heading {
  float:right;
}

maximum value of int

#include <climits>
#include <iostream>
using namespace std;

int main() {
  cout << INT_MAX << endl;
}

Showing which files have changed between two revisions

There are two branches lets say

  • A (Branch on which you are working)
  • B (Another branch with which you want to compare)

Being in branch A you can type

git diff --color B

then this will give you a output of

enter image description here

The important point about this is

  1. Text in green is inside present in Branch A

  2. Text in red is present in Branch B

Right way to split an std::string into a vector<string>

Tweaked version from Techie Delight:

#include <string>
#include <vector>

std::vector<std::string> split(const std::string& str, char delim) {
    std::vector<std::string> strings;
    size_t start;
    size_t end = 0;
    while ((start = str.find_first_not_of(delim, end)) != std::string::npos) {
        end = str.find(delim, start);
        strings.push_back(str.substr(start, end - start));
    }
    return strings;
}

How can I loop through a C++ map of maps?

With C++17 (or later), you can use the "structured bindings" feature, which lets you define multiple variables, with different names, using a single tuple/pair. Example:

for (const auto& [name, description] : planet_descriptions) {
    std::cout << "Planet " << name << ":\n" << description << "\n\n";
}

The original proposal (by luminaries Bjarne Stroustrup, Herb Sutter and Gabriel Dos Reis) is fun to read (and the suggested syntax is more intuitive IMHO); there's also the proposed wording for the standard which is boring to read but is closer to what will actually go in.

How to use RecyclerView inside NestedScrollView?

I used RecyclerView inside a NestedScrollView and it worked for me. The only gotcha I had to keep in mind was that a NestedScrollView takes only one child view. So in my case I used of LienearLayout viewgroup which was housing my RecyclerView plus a number of other views that I needed.

I experience one issue putting my RecyclerView inside the NestedScrollView. I realized that scrolling the content of my RecyclerView slacked.

I later realized that my RecyclerView was receiving the scrolling event and therefore was conflicting with the scrolling behavior of the NestedScrollView.

So to solve that problem, I had to disable the scroll functionality of my RecyclerView with this method movieListNewRecyclerView.setNestedScrollingEnabled(false);

You can checkout my Instagram for a short video of what I actually did. This is my instagram handle ofelix03

Click this image to see what I did

How to Correctly Check if a Process is running and Stop it

If you don't need to display exact result "running" / "not runnuning", you could simply:

ps notepad -ErrorAction SilentlyContinue | kill -PassThru

If the process was not running, you'll get no results. If it was running, you'll receive get-process output, and the process will be stopped.

Unknown Column In Where Clause

May be it helps.

You can

SET @somevar := '';
SELECT @somevar AS user_name FROM users WHERE (@somevar := `u_name`) = "john";

It works.

BUT MAKE SURE WHAT YOU DO!

  • Indexes are NOT USED here
  • There will be scanned FULL TABLE - you hasn't specified the LIMIT 1 part
  • So, - THIS QUERY WILL BE SLLLOOOOOOW on huge tables.

But, may be it helps in some cases

What is the copy-and-swap idiom?

This answer is more like an addition and a slight modification to the answers above.

In some versions of Visual Studio (and possibly other compilers) there is a bug that is really annoying and doesn't make sense. So if you declare/define your swap function like this:

friend void swap(A& first, A& second) {

    std::swap(first.size, second.size);
    std::swap(first.arr, second.arr);

}

... the compiler will yell at you when you call the swap function:

enter image description here

This has something to do with a friend function being called and this object being passed as a parameter.


A way around this is to not use friend keyword and redefine the swap function:

void swap(A& other) {

    std::swap(size, other.size);
    std::swap(arr, other.arr);

}

This time, you can just call swap and pass in other, thus making the compiler happy:

enter image description here


After all, you don't need to use a friend function to swap 2 objects. It makes just as much sense to make swap a member function that has one other object as a parameter.

You already have access to this object, so passing it in as a parameter is technically redundant.

Is there a color code for transparent in HTML?

Yeah I think the best way to transparent the background colour (make opacity only for the background) is using

.style{
        background-color: rgba(100, 100, 100, 0.5);
}

Above statement 0.5 is the opacity value.

It only apply the opacity changes to the background colour (not all elements')

The "opacity" attribute in the CSS will transparent all the elements in the block.

C - freeing structs

This way you only need to free the structure because the fields are arrays with static sizes which will be allocated as part of the structure. This is also the reason that the addresses you see match: the array is the first thing in that structure. If you declared the fields as char * you would have to manually malloc and free them as well.

sorting and paging with gridview asp.net

Save your sorting order in a ViewState.

private const string ASCENDING = " ASC";
private const string DESCENDING = " DESC";

public SortDirection GridViewSortDirection
{
    get
    {
        if (ViewState["sortDirection"] == null)
            ViewState["sortDirection"] = SortDirection.Ascending;

        return (SortDirection) ViewState["sortDirection"];                
    }
    set { ViewState["sortDirection"] = value; } 
}

protected void GridView_Sorting(object sender, GridViewSortEventArgs e)
{
    string sortExpression = e.SortExpression;

    if (GridViewSortDirection == SortDirection.Ascending)
    {
        GridViewSortDirection = SortDirection.Descending;
        SortGridView(sortExpression, DESCENDING);
    }
    else
    {
        GridViewSortDirection = SortDirection.Ascending;
        SortGridView(sortExpression, ASCENDING); 
    }   

}

private void SortGridView(string sortExpression,string direction)
{
    //  You can cache the DataTable for improving performance
    DataTable dt = GetData().Tables[0]; 

    DataView dv = new DataView(dt); 
    dv.Sort = sortExpression + direction;         

    GridView1.DataSource = dv;
    GridView1.DataBind();         
}

Why you don't want to use existing sorting functionality? You can always customize it.

Sorting Data in a GridView Web Server Control at MSDN

Here is an example with customization:

http://www.netomatix.com/development/GridViewSorting.aspx

Find text string using jQuery?

Take a look at highlight (jQuery plugin).