#Amfphp | Programs & Examples on Amfphp

What is simplest way to read a file into String?

Another alternative approach is:

How do I create a Java string from the contents of a file?

Other option is to use utilities provided open source libraries
http://commons.apache.org/io/api-1.4/index.html?org/apache/commons/io/IOUtils.html

Why java doesn't provide such a common util API ?
a) to keep the APIs generic so that encoding, buffering etc is handled by the programmer.
b) make programmers do some work and write/share opensource util libraries :D ;-)

how to format date in Component of angular 5

There is equally formatDate

const format = 'dd/MM/yyyy';
const myDate = '2019-06-29';
const locale = 'en-US';
const formattedDate = formatDate(myDate, format, locale);

According to the API it takes as param either a date string, a Date object, or a timestamp.

Gotcha: Out of the box, only en-US is supported.

If you need to add another locale, you need to add it and register it in you app.module, for example for Spanish:

import { registerLocaleData } from '@angular/common';
import localeES from "@angular/common/locales/es";
registerLocaleData(localeES, "es");

Don't forget to add corresponding import:

import { formatDate } from "@angular/common";

List changes unexpectedly after assignment. How do I clone or copy it to prevent this?

Python's idiom for doing this is newList = oldList[:]

Verify host key with pysftp

One option is to disable the host key requirement:

import pysftp
cnopts = pysftp.CnOpts()
cnopts.hostkeys = None   
with pysftp.Connection(host, username, password, cnopts=cnopts) as sftp:
    sftp.put(local_path, remote_path)

You can find more info about that here: https://stackoverflow.com/a/38355117/1060738

Important note:

By setting cnopts.hostkeys=None you'll lose the protection against Man-in-the-middle attacks by doing so. Use @martin-prikryl answer to avoid that.

ActionBarActivity is deprecated

According to this video of Android Developers you should only make two changes

enter image description here

How is length implemented in Java Arrays?

According to the Java Language Specification (specifically §10.7 Array Members) it is a field:

The public final field length, which contains the number of components of the array (length may be positive or zero).

Internally the value is probably stored somewhere in the object header, but that is an implementation detail and depends on the concrete JVM implementation.

The HotSpot VM (the one in the popular Oracle (formerly Sun) JRE/JDK) stores the size in the object-header:

[...] arrays have a third header field, for the array size.

Post to another page within a PHP script

index.php

$url = 'http://[host]/test.php';
$json = json_encode(['name' => 'Jhonn', 'phone' => '128000000000']);

$options = ['http' => [
    'method' => 'POST',
    'header' => 'Content-type:application/json',
    'content' => $json
]];

$context = stream_context_create($options);
$response = file_get_contents($url, false, $context);

test.php

$raw = file_get_contents('php://input');
$data = json_decode($raw, true);
echo $data['name']; // Jhonn

Javascript: Load an Image from url and display

When the button is clicked, get the value of the input and use it to create an image element which is appended to the body (or anywhere else) :

<html>
<body>
<form>
    <input type="text" id="imagename" value="" />
    <input type="button" id="btn" value="GO" />
</form>
    <script type="text/javascript">
        document.getElementById('btn').onclick = function() {
            var val = document.getElementById('imagename').value,
                src = 'http://webpage.com/images/' + val +'.png',
                img = document.createElement('img');

            img.src = src;
            document.body.appendChild(img);
        }
    </script>
</body>
</html>

FIDDLE

the same in jQuery:

$('#btn').on('click', function() {
    var img = $('<img />', {src : 'http://webpage.com/images/' + $('#imagename').val() +'.png'});
    img.appendTo('body');
});

var functionName = function() {} vs function functionName() {}

I use the variable approach in my code for a very specific reason, the theory of which has been covered in an abstract way above, but an example might help some people like me, with limited JavaScript expertise.

I have code that I need to run with 160 independently-designed brandings. Most of the code is in shared files, but branding-specific stuff is in a separate file, one for each branding.

Some brandings require specific functions, and some do not. Sometimes I have to add new functions to do new branding-specific things. I am happy to change the shared coded, but I don't want to have to change all 160 sets of branding files.

By using the variable syntax, I can declare the variable (a function pointer essentially) in the shared code and either assign a trivial stub function, or set to null.

The one or two brandings that need a specific implementation of the function can then define their version of the function and assign this to the variable if they want, and the rest do nothing. I can test for a null function before I execute it in the shared code.

From people's comments above, I gather it may be possible to redefine a static function too, but I think the variable solution is nice and clear.

Check if a String contains numbers Java

Below code snippet will tell whether the String contains digit or not

str.matches(".*\\d.*")
or
str.matches(.*[0-9].*)

For example

String str = "abhinav123";

str.matches(".*\\d.*") or str.matches(.*[0-9].*)  will return true 

str = "abhinav";

str.matches(".*\\d.*") or str.matches(.*[0-9].*)  will return false

How to timeout a thread

Indeed rather use ExecutorService instead of Timer, here's an SSCCE:

package com.stackoverflow.q2275443;

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

public class Test {
    public static void main(String[] args) throws Exception {
        ExecutorService executor = Executors.newSingleThreadExecutor();
        Future<String> future = executor.submit(new Task());

        try {
            System.out.println("Started..");
            System.out.println(future.get(3, TimeUnit.SECONDS));
            System.out.println("Finished!");
        } catch (TimeoutException e) {
            future.cancel(true);
            System.out.println("Terminated!");
        }

        executor.shutdownNow();
    }
}

class Task implements Callable<String> {
    @Override
    public String call() throws Exception {
        Thread.sleep(4000); // Just to demo a long running task of 4 seconds.
        return "Ready!";
    }
}

Play a bit with the timeout argument in Future#get() method, e.g. increase it to 5 and you'll see that the thread finishes. You can intercept the timeout in the catch (TimeoutException e) block.

Update: to clarify a conceptual misunderstanding, the sleep() is not required. It is just used for SSCCE/demonstration purposes. Just do your long running task right there in place of sleep(). Inside your long running task, you should be checking if the thread is not interrupted as follows:

while (!Thread.interrupted()) {
    // Do your long running task here.
}

Is it possible to modify a registry entry via a .bat/.cmd script?

You can use the REG command. From http://www.ss64.com/nt/reg.html:

Syntax:

   REG QUERY [ROOT\]RegKey /v ValueName [/s]
   REG QUERY [ROOT\]RegKey /ve  --This returns the (default) value

   REG ADD [ROOT\]RegKey /v ValueName [/t DataType] [/S Separator] [/d Data] [/f]
   REG ADD [ROOT\]RegKey /ve [/d Data] [/f]  -- Set the (default) value

   REG DELETE [ROOT\]RegKey /v ValueName [/f]
   REG DELETE [ROOT\]RegKey /ve [/f]  -- Remove the (default) value
   REG DELETE [ROOT\]RegKey /va [/f]  -- Delete all values under this key

   REG COPY  [\\SourceMachine\][ROOT\]RegKey [\\DestMachine\][ROOT\]RegKey

   REG EXPORT [ROOT\]RegKey FileName.reg
   REG IMPORT FileName.reg
   REG SAVE [ROOT\]RegKey FileName.hiv
   REG RESTORE \\MachineName\[ROOT]\KeyName FileName.hiv

   REG LOAD FileName KeyName
   REG UNLOAD KeyName

   REG COMPARE [ROOT\]RegKey [ROOT\]RegKey [/v ValueName] [Output] [/s]
   REG COMPARE [ROOT\]RegKey [ROOT\]RegKey [/ve] [Output] [/s]

Key:
   ROOT :
         HKLM = HKey_Local_machine (default)
         HKCU = HKey_current_user
         HKU  = HKey_users
         HKCR = HKey_classes_root

   ValueName : The value, under the selected RegKey, to edit.
               (default is all keys and values)

   /d Data   : The actual data to store as a "String", integer etc

   /f        : Force an update without prompting "Value exists, overwrite Y/N"

   \\Machine : Name of remote machine - omitting defaults to current machine.
                Only HKLM and HKU are available on remote machines.

   FileName  : The filename to save or restore a registry hive.

   KeyName   : A key name to load a hive file into. (Creating a new key)

   /S        : Query all subkeys and values.

   /S Separator : Character to use as the separator in REG_MULTI_SZ values
                  the default is "\0" 

   /t DataType  : REG_SZ (default) | REG_DWORD | REG_EXPAND_SZ | REG_MULTI_SZ

   Output    : /od (only differences) /os (only matches) /oa (all) /on (no output)

Does hosts file exist on the iPhone? How to change it?

Don't change the DNS on the phone. Instead, connect with wifi to the local network and you are all set.

At my office, we have internal servers with internal DNS that are not exposed to the Internet. I just connect with iPhone to the office wifi and can then access them fine.

YMMV, but instead of configuring the phone DNS, it feels to me that just setting up local internal DNS and wifi is a cleaner and easier solution.

How can I get a List from some class properties with Java 8 Stream?

You can use map :

List<String> names = 
    personList.stream()
              .map(Person::getName)
              .collect(Collectors.toList());

EDIT :

In order to combine the Lists of friend names, you need to use flatMap :

List<String> friendNames = 
    personList.stream()
              .flatMap(e->e.getFriends().stream())
              .collect(Collectors.toList());

Uncaught TypeError: Object #<Object> has no method 'movingBoxes'

I found that I was using a selector for my rendorTo div that I was using to render my column highcharts graph. Apparently it adds the selector for you so you just need to pass id.

renderTo: $('#myGraphDiv') to a string 'myGraphDiv' this fixed the error hope this helps someone else out as well.

How to update Pandas from Anaconda and is it possible to use eclipse with this last

Simply type conda update pandas in your preferred shell (on Windows, use cmd; if Anaconda is not added to your PATH use the Anaconda prompt). You can of course use Eclipse together with Anaconda, but you need to specify the Python-Path (the one in the Anaconda-Directory). See this document for a detailed instruction.

Read and write into a file using VBScript

Don't think so...you can only use openTextFile for reading (1), writing (2), or appending (8). Reference here.

If you were using VB6 instead of VBScript, you could do:

Open "Filename" [For Mode] [AccessRestriction] [LockType] As #FileNumber

Using the Random mode. For example:

Open "C:\New\maddy.txt" For Random As #1

How to change font-size of a tag using inline css?

use this attribute in style

font-size: 11px !important;//your font size

by !important it override your css

How can I parse a CSV string with JavaScript, which contains comma in data?

Adding one more to the list, because I find all of the above not quite "KISS" enough.

This one uses regex to find either commas or newlines while skipping over quoted items. Hopefully this is something noobies can read through on their own. The splitFinder regexp has three things it does (split by a |):

, - finds commas
\r?\n - finds new lines, (potentially with carriage return if the exporter was nice)
"(\\"|[^"])*?" - skips anynthing surrounded in quotes, because commas and newlines don't matter in there. If there is an escaped quote \\" in the quoted item, it will get captured before an end quote can be found.

_x000D_

const splitFinder = /,|\r?\n|"(\\"|[^"])*?"/g;_x000D_
_x000D_
function csvTo2dArray(parseMe) {_x000D_
  let currentRow = [];_x000D_
  const rowsOut = [currentRow];_x000D_
  let lastIndex = splitFinder.lastIndex = 0;_x000D_
  _x000D_
  // add text from lastIndex to before a found newline or comma_x000D_
  const pushCell = (endIndex) => {_x000D_
    endIndex = endIndex || parseMe.length;_x000D_
    const addMe = parseMe.substring(lastIndex, endIndex);_x000D_
    // remove quotes around the item_x000D_
    currentRow.push(addMe.replace(/^"|"$/g, ""));_x000D_
    lastIndex = splitFinder.lastIndex;_x000D_
  }_x000D_
_x000D_
_x000D_
  let regexResp;_x000D_
  // for each regexp match (either comma, newline, or quoted item)_x000D_
  while (regexResp = splitFinder.exec(parseMe)) {_x000D_
    const split = regexResp[0];_x000D_
_x000D_
    // if it's not a quote capture, add an item to the current row_x000D_
    // (quote captures will be pushed by the newline or comma following)_x000D_
    if (split.startsWith(`"`) === false) {_x000D_
      const splitStartIndex = splitFinder.lastIndex - split.length;_x000D_
      pushCell(splitStartIndex);_x000D_
_x000D_
      // then start a new row if newline_x000D_
      const isNewLine = /^\r?\n$/.test(split);_x000D_
      if (isNewLine) { rowsOut.push(currentRow = []); }_x000D_
    }_x000D_
  }_x000D_
  // make sure to add the trailing text (no commas or newlines after)_x000D_
  pushCell();_x000D_
  return rowsOut;_x000D_
}_x000D_
_x000D_
const rawCsv = `a,b,c\n"test\r\n","comma, test","\r\n",",",\nsecond,row,ends,with,empty\n"quote\"test"`_x000D_
const rows = csvTo2dArray(rawCsv);_x000D_
console.log(rows);

_x000D_

Append text to textarea with javascript

Tray to add text with html value to textarea but it wil not works

value :

$(document).on('click', '.edit_targets_btn', function() {
            $('#add_edit_targets').modal('show');
            $('#add_edit_targets_form')[0].reset();
            $('#targets_modal_title').text('Doel bijwerken');
            $('#action').val('targets_update');
            $('#targets_submit_btn').val('Opslaan');

            $('#callcenter_targets_id').val($(this).attr("callcenter_targets_id"));
            $('#targets_title').val($(this).attr("title"));
            $("#targets_content").append($(this).attr("content"));

            tinymce.init({
                selector: '#targets_content',
                setup: function (editor) {
                    editor.on('change', function () {
                        tinymce.triggerSave();
                    });
                },
                browser_spellcheck : true,
                plugins: ['advlist autolink lists image charmap print preview anchor', 'searchreplace visualblocks code fullscreen', 'insertdatetime media table paste code help wordcount', 'autoresize'],
                toolbar: 'undo redo | formatselect | ' + ' bold italic backcolor | alignleft aligncenter ' + ' alignright alignjustify | bullist numlist outdent indent |' + ' removeformat | image | help',
                relative_urls : false,
                remove_script_host : false,
                image_list: [<?php $stmt = $db->query('SELECT * FROM images WHERE users_id = ' . $get_user_users_id); foreach ($stmt as $row) { ?>{title: '<?=$row['name']?>', value: '<?=$imgurl?>/image_uploads/<?=$row['src']?>'},<?php } ?>],
                min_height: 250,
                branding: false
            });
        });

SQL Error: ORA-01861: literal does not match format string 01861

The format you use for the date doesn't match to Oracle's default date format.

A default installation of Oracle Database sets the DEFAULT DATE FORMAT to dd-MMM-yyyy.

Either use the function TO_DATE(dateStr, formatStr) or simply use dd-MMM-yyyy date format model.

Linq to Entities - SQL "IN" clause

I also tried to work with an SQL-IN-like thing - querying against an Entity Data Model. My approach is a string builder to compose a big OR-expression. That's terribly ugly, but I'm afraid it's the only way to go right now.

Now well, that looks like this:

Queue<Guid> productIds = new Queue<Guid>(Products.Select(p => p.Key));
if(productIds.Count > 0)
{
    StringBuilder sb = new StringBuilder();
    sb.AppendFormat("{0}.ProductId = Guid\'{1}\'", entities.Products.Name, productIds.Dequeue());
    while(productIds.Count > 0)
    {
        sb.AppendFormat(" OR {0}.ProductId = Guid\'{1}\'",
          entities.Products.Name, productIds.Dequeue());
    }
}

Working with GUIDs in this context: As you can see above, there is always the word "GUID" before the GUID ifself in the query string fragments. If you don't add this, ObjectQuery<T>.Where throws the following exception:

The argument types 'Edm.Guid' and 'Edm.String' are incompatible for this operation., near equals expression, line 6, column 14.

Found this in MSDN Forums, might be helpful to have in mind.

Matthias

... looking forward for the next version of .NET and Entity Framework, when everything get's better. :)

Javascript document.getElementById("id").value returning null instead of empty string when the element is an empty text box

Please check this fiddle and let me know if you get an alert of null value. I have copied your code there and added a couple of alerts. Just like others, I also dont see a null being returned, I get an empty string. Which browser are you using?

Delete topic in Kafka 0.8.1.1

bin/kafka-topics.sh –delete –zookeeper localhost:2181 –topic <topic-name>

Using .otf fonts on web browsers

From the Google Font Directory examples:

@font-face {
  font-family: 'Tangerine';
  font-style: normal;
  font-weight: normal;
  src: local('Tangerine'), url('http://example.com/tangerine.ttf') format('truetype');
}
body {
  font-family: 'Tangerine', serif;
  font-size: 48px;
}

This works cross browser with .ttf, I believe it may work with .otf. (Wikipedia says .otf is mostly backwards compatible with .ttf) If not, you can convert the .otf to .ttf

Here are some good sites:

Good primer:

http://www.alistapart.com/articles/cssatten
Other Info:

http://randsco.com/index.php/2009/07/04/p680

Getting time and date from timestamp with php

$timestamp='2014-11-21 16:38:00';

list($date,$time)=explode(' ',$timestamp);

// just time

preg_match("/ (\d\d:\d\d):\d\d$/",$timestamp,$match);
echo "\n<br>".$match[1];

Export tables to an excel spreadsheet in same directory

Lawrence has given you a good answer. But if you want more control over what gets exported to where in Excel see Modules: Sample Excel Automation - cell by cell which is slow and Modules: Transferring Records to Excel with Automation You can do things such as export the recordset starting in row 2 and insert custom text in row 1. As well as any custom formatting required.

Accessing value inside nested dictionaries

You can use the get() on each dict. Make sure that you have added the None check for each access.

How can I open a website in my web browser using Python?

I think it should be

import webbrowser

webbrowser.open('http://gatedin.com')

NOTE: make sure that you give http or https

if you give "www." instead of "http:" instead of opening a broser the interprete displays boolean OutPut TRUE. here you are importing webbrowser library

Is there an upper bound to BigInteger?

BigInteger would only be used if you know it will not be a decimal and there is a possibility of the long data type not being large enough. BigInteger has no cap on its max size (as large as the RAM on the computer can hold).

From here.

It is implemented using an int[]:

  110       /**
  111        * The magnitude of this BigInteger, in <i>big-endian</i> order: the
  112        * zeroth element of this array is the most-significant int of the
  113        * magnitude.  The magnitude must be "minimal" in that the most-significant
  114        * int ({@code mag[0]}) must be non-zero.  This is necessary to
  115        * ensure that there is exactly one representation for each BigInteger
  116        * value.  Note that this implies that the BigInteger zero has a
  117        * zero-length mag array.
  118        */
  119       final int[] mag;

From the source

From the Wikipedia article Arbitrary-precision arithmetic:

Several modern programming languages have built-in support for bignums, and others have libraries available for arbitrary-precision integer and floating-point math. Rather than store values as a fixed number of binary bits related to the size of the processor register, these implementations typically use variable-length arrays of digits.

What does 'stale file handle' in Linux mean?

When the directory is deleted, the inode for that directory (and the inodes for its contents) are recycled. The pointer your shell has to that directory's inode (and its contents's inodes) are now no longer valid. When the directory is restored from backup, the old inodes are not (necessarily) reused; the directory and its contents are stored on random inodes. The only thing that stays the same is that the parent directory reuses the same name for the restored directory (because you told it to).

Now if you attempt to access the contents of the directory that your original shell is still pointing to, it communicates that request to the file system as a request for the original inode, which has since been recycled (and may even be in use for something entirely different now). So you get a stale file handle message because you asked for some nonexistent data.

When you perform a cd operation, the shell reevaluates the inode location of whatever destination you give it. Now that your shell knows the new inode for the directory (and the new inodes for its contents), future requests for its contents will be valid.

Redeploy alternatives to JRebel

I have written an article about DCEVM: Spring-mvc + Velocity + DCEVM

I think it's worth it, since my environment is running without any problems.

#1130 - Host ‘localhost’ is not allowed to connect to this MySQL server

Use this in your my.ini under

[mysqldump]
    user=root
    password=anything

Can't access 127.0.0.1

Just one command did the work

netsh http add iplisten 127.0.0.1

How to tell Jackson to ignore a field during serialization if its value is null?

If in Spring Boot, you can customize the jackson ObjectMapper directly through property files.

Example application.yml:

spring:
  jackson:
    default-property-inclusion: non_null # only include props if non-null

Possible values are:

always|non_null|non_absent|non_default|non_empty

More: https://docs.spring.io/spring-boot/docs/current/reference/html/howto-spring-mvc.html#howto-customize-the-jackson-objectmapper

Excel VBA: AutoFill Multiple Cells with Formulas

Based on my Comment here is one way to get what you want done:

Start byt selecting any cell in your range and Press Ctrl + T

This will give you this pop up:

enter image description here

make sure the Where is your table text is correct and click ok you will now have:

enter image description here

Now If you add a column header in D it will automatically be added to the table all the way to the last row:

enter image description here

Now If you enter a formula into this column:

enter image description here

After you enter it, the formula will be auto filled all the way to last row:

enter image description here

Now if you add a new row at the next row under your table:

enter image description here

Once entered it will be resized to the width of your table and all columns with formulas will be added also:

enter image description here

Hope this solves your problem!

Why doesn't "System.out.println" work in Android?

Of course, to see the result in logcat, you should set the Log level at least to "Info" (Log level in logcat); otherwise, as it happened to me, you won't see your output.

Predicate in Java

You can view the java doc examples or the example of usage of Predicate here

Basically it is used to filter rows in the resultset based on any specific criteria that you may have and return true for those rows that are meeting your criteria:

 // the age column to be between 7 and 10
    AgeFilter filter = new AgeFilter(7, 10, 3);

    // set the filter.
    resultset.beforeFirst();
    resultset.setFilter(filter);

mongodb group values by multiple fields

Below query will provide exactly the same result as given in the desired response:

db.books.aggregate([
    {
        $group: {
            _id: { addresses: "$addr", books: "$book" },
            num: { $sum :1 }
        }
    },
    {
        $group: {
            _id: "$_id.addresses",
            bookCounts: { $push: { bookName: "$_id.books",count: "$num" } }
        }
    },
    {
        $project: {
            _id: 1,
            bookCounts:1,
            "totalBookAtAddress": {
                "$sum": "$bookCounts.count"
            }
        }
    }

])

The response will be looking like below:

/* 1 */
{
    "_id" : "address4",
    "bookCounts" : [
        {
            "bookName" : "book3",
            "count" : 1
        }
    ],
    "totalBookAtAddress" : 1
},

/* 2 */
{
    "_id" : "address90",
    "bookCounts" : [
        {
            "bookName" : "book33",
            "count" : 1
        }
    ],
    "totalBookAtAddress" : 1
},

/* 3 */
{
    "_id" : "address15",
    "bookCounts" : [
        {
            "bookName" : "book1",
            "count" : 1
        }
    ],
    "totalBookAtAddress" : 1
},

/* 4 */
{
    "_id" : "address3",
    "bookCounts" : [
        {
            "bookName" : "book9",
            "count" : 1
        }
    ],
    "totalBookAtAddress" : 1
},

/* 5 */
{
    "_id" : "address5",
    "bookCounts" : [
        {
            "bookName" : "book1",
            "count" : 1
        }
    ],
    "totalBookAtAddress" : 1
},

/* 6 */
{
    "_id" : "address1",
    "bookCounts" : [
        {
            "bookName" : "book1",
            "count" : 3
        },
        {
            "bookName" : "book5",
            "count" : 1
        }
    ],
    "totalBookAtAddress" : 4
},

/* 7 */
{
    "_id" : "address2",
    "bookCounts" : [
        {
            "bookName" : "book1",
            "count" : 2
        },
        {
            "bookName" : "book5",
            "count" : 1
        }
    ],
    "totalBookAtAddress" : 3
},

/* 8 */
{
    "_id" : "address77",
    "bookCounts" : [
        {
            "bookName" : "book11",
            "count" : 1
        }
    ],
    "totalBookAtAddress" : 1
},

/* 9 */
{
    "_id" : "address9",
    "bookCounts" : [
        {
            "bookName" : "book99",
            "count" : 1
        }
    ],
    "totalBookAtAddress" : 1
}

How to store a dataframe using Pandas

Arctic is a high performance datastore for Pandas, numpy and other numeric data. It sits on top of MongoDB. Perhaps overkill for the OP, but worth mentioning for other folks stumbling across this post

What are my options for storing data when using React Native? (iOS and Android)

We dont need redux-persist we can simply use redux for persistance.

react-redux + AsyncStorage = redux-persist

so inside createsotre file simply add these lines

store.subscribe(async()=> await AsyncStorage.setItem("store", JSON.stringify(store.getState())))

this will update the AsyncStorage whenever there are some changes in the redux store.

Then load the json converted store. when ever the app loads. and set the store again.

Because redux-persist creates issues when using wix react-native-navigation. If that's the case then I prefer to use simple redux with above subscriber function

jQuery scroll to element

If you are only handling scrolling to an input element, you can use focus(). For example, if you wanted to scroll to the first visible input:

$(':input:visible').first().focus();

Or the first visible input in an container with class .error:

$('.error :input:visible').first().focus();

Thanks to Tricia Ball for pointing this out!

How to use mongoose findOne

Use obj[0].nick and you will get desired result,

javascript - replace dash (hyphen) with a space

replace() returns an new string, and the original string is not modified. You need to do

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

openCV program compile error "libopencv_core.so.2.4: cannot open shared object file: No such file or directory" in ubuntu 12.04

You haven't put the shared library in a location where the loader can find it. look inside the /usr/local/opencv and /usr/local/opencv2 folders and see if either of them contains any shared libraries (files beginning in lib and usually ending in .so). when you find them, create a file called /etc/ld.so.conf.d/opencv.conf and write to it the paths to the folders where the libraries are stored, one per line.

for example, if the libraries were stored under /usr/local/opencv/libopencv_core.so.2.4 then I would write this to my opencv.conf file:

/usr/local/opencv/

Then run

sudo ldconfig -v

If you can't find the libraries, try running

sudo updatedb && locate libopencv_core.so.2.4

in a shell. You don't need to run updatedb if you've rebooted since compiling OpenCV.

References:

About shared libraries on Linux: http://www.eyrie.org/~eagle/notes/rpath.html

About adding the OpenCV shared libraries: http://opencv.willowgarage.com/wiki/InstallGuide_Linux

JavaScript: Global variables after Ajax requests

AJAX stands for Asynchronous JavaScript and XML. Thus, the post to the server happens out-of-sync with the rest of the function. Try some code like this instead (it just breaks the shorthand $.post out into the longer $.ajax call and adds the async option).

var it_works = false;

$.ajax({
  type: 'POST',
  async: false,
  url: "some_file.php",
  data: "",
  success: function() {it_works = true;}
});

alert(it_works);

Hope this helps!

JPA Criteria API - How to add JOIN clause (as general sentence as possible)

You don't need to learn JPA. You can use my easy-criteria for JPA2 (https://sourceforge.net/projects/easy-criteria/files/). Here is the example

CriteriaComposer<Pet> petCriteria CriteriaComposer.from(Pet.class).
where(Pet_.type, EQUAL, "Cat").join(Pet_.owner).where(Ower_.name,EQUAL, "foo");

List<Pet> result = CriteriaProcessor.findAllEntiry(petCriteria);

List<Tuple> result =  CriteriaProcessor.findAllTuple(petCriteria);

pandas: best way to select all columns whose names start with X

Just perform a list comprehension to create your columns:

In [28]:

filter_col = [col for col in df if col.startswith('foo')]
filter_col
Out[28]:
['foo.aa', 'foo.bars', 'foo.fighters', 'foo.fox', 'foo.manchu']
In [29]:

df[filter_col]
Out[29]:
   foo.aa  foo.bars  foo.fighters  foo.fox foo.manchu
0     1.0         0             0        2         NA
1     2.1         0             1        4          0
2     NaN         0           NaN        1          0
3     4.7         0             0        0          0
4     5.6         0             0        0          0
5     6.8         1             0        5          0

Another method is to create a series from the columns and use the vectorised str method startswith:

In [33]:

df[df.columns[pd.Series(df.columns).str.startswith('foo')]]
Out[33]:
   foo.aa  foo.bars  foo.fighters  foo.fox foo.manchu
0     1.0         0             0        2         NA
1     2.1         0             1        4          0
2     NaN         0           NaN        1          0
3     4.7         0             0        0          0
4     5.6         0             0        0          0
5     6.8         1             0        5          0

In order to achieve what you want you need to add the following to filter the values that don't meet your ==1 criteria:

In [36]:

df[df[df.columns[pd.Series(df.columns).str.startswith('foo')]]==1]
Out[36]:
   bar.baz  foo.aa  foo.bars  foo.fighters  foo.fox foo.manchu nas.foo
0      NaN       1       NaN           NaN      NaN        NaN     NaN
1      NaN     NaN       NaN             1      NaN        NaN     NaN
2      NaN     NaN       NaN           NaN        1        NaN     NaN
3      NaN     NaN       NaN           NaN      NaN        NaN     NaN
4      NaN     NaN       NaN           NaN      NaN        NaN     NaN
5      NaN     NaN         1           NaN      NaN        NaN     NaN

EDIT

OK after seeing what you want the convoluted answer is this:

In [72]:

df.loc[df[df[df.columns[pd.Series(df.columns).str.startswith('foo')]] == 1].dropna(how='all', axis=0).index]
Out[72]:
   bar.baz  foo.aa  foo.bars  foo.fighters  foo.fox foo.manchu nas.foo
0      5.0     1.0         0             0        2         NA      NA
1      5.0     2.1         0             1        4          0       0
2      6.0     NaN         0           NaN        1          0       1
5      6.8     6.8         1             0        5          0       0

How can I stop the browser back button using JavaScript?

<script>
    window.location.hash = "no-back-button";

    // Again because Google Chrome doesn't insert
    // the first hash into the history
    window.location.hash = "Again-No-back-button"; 

    window.onhashchange = function(){
        window.location.hash = "no-back-button";
    }
</script>

How to sum digits of an integer in java?

In Java 8,

public int sum(int number) {
  return (number + "").chars()
                      .map(digit -> digit % 48)
                      .sum();
}

Converts the number to a string and then each character is mapped to it's digit value by subtracting ascii value of '0' (48) and added to the final sum.

Bootstrap 4 img-circle class not working

In Bootstrap 4 it was renamed to .rounded-circle

Usage :

<div class="col-xs-7">
    <img src="img/gallery2.JPG" class="rounded-circle" alt="HelPic>
</div>

See migration docs from bootstrap.

Parsing Query String in node.js

There's also the QueryString module's parse() method:

var http = require('http'),
    queryString = require('querystring');

http.createServer(function (oRequest, oResponse) {

    var oQueryParams;

    // get query params as object
    if (oRequest.url.indexOf('?') >= 0) {
        oQueryParams = queryString.parse(oRequest.url.replace(/^.*\?/, ''));

        // do stuff
        console.log(oQueryParams);
    }

    oResponse.writeHead(200, {'Content-Type': 'text/plain'});
    oResponse.end('Hello world.');

}).listen(1337, '127.0.0.1');

Passing an array to a query using a WHERE clause

ints:

$query = "SELECT * FROM `$table` WHERE `$column` IN(".implode(',',$array).")";

strings:

$query = "SELECT * FROM `$table` WHERE `$column` IN('".implode("','",$array)."')";

Eclipse: How to install a plugin manually?

Download your plugin
Open Eclipse
From the menu choose: Help / Install New Software...
Click the Add button
In the Add Repository dialog that appears, click the Archive button next to the Location field
Select your plugin file, click OK

You could also just copy plugins to the eclipse/plugins directory, but it's not recommended.

XmlWriter to Write to a String Instead of to a File

Guys don't forget to call xmlWriter.Close() and xmlWriter.Dispose() or else your string won't finish creating. It will just be an empty string

How can I draw circle through XML Drawable - Android?

no need for the padding or the corners.

here's a sample:

<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="oval" >
    <gradient android:startColor="#FFFF0000" android:endColor="#80FF00FF"
        android:angle="270"/>
</shape>

based on :

https://stackoverflow.com/a/10104037/878126

Now() function with time trim

There is a Date function.

How to access command line arguments of the caller inside a function?

If you want to have your arguments C style (array of arguments + number of arguments) you can use $@ and $#.

$# gives you the number of arguments.
$@ gives you all arguments. You can turn this into an array by args=("$@").

So for example:

args=("$@")
echo $# arguments passed
echo ${args[0]} ${args[1]} ${args[2]}

Note that here ${args[0]} actually is the 1st argument and not the name of your script.

"No such file or directory" error when executing a binary

readelf -a xxx

 INTERP         
  0x0000000000000238 0x0000000000400238 0x0000000000400238           
  0x000000000000001c 0x000000000000001c  R      1
  [Requesting program interpreter: /lib64/ld-linux-x86-64.so.2]

Significance of ios_base::sync_with_stdio(false); cin.tie(NULL);

Using ios_base::sync_with_stdio(false); is sufficient to decouple the C and C++ streams. You can find a discussion of this in Standard C++ IOStreams and Locales, by Langer and Kreft. They note that how this works is implementation-defined.

The cin.tie(NULL) call seems to be requesting a decoupling between the activities on cin and cout. I can't explain why using this with the other optimization should cause a crash. As noted, the link you supplied is bad, so no speculation here.

Why is "1000000000000000 in range(1000000000000001)" so fast in Python 3?

It's all about a lazy approach to the evaluation and some extra optimization of range. Values in ranges don't need to be computed until real use, or even further due to extra optimization.

By the way, your integer is not such big, consider sys.maxsize

sys.maxsize in range(sys.maxsize) is pretty fast

due to optimization - it's easy to compare given integer just with min and max of range.

but:

Decimal(sys.maxsize) in range(sys.maxsize) is pretty slow.

(in this case, there is no optimization in range, so if python receives unexpected Decimal, python will compare all numbers)

You should be aware of an implementation detail but should not be relied upon, because this may change in the future.

Change Volley timeout duration

I ended up adding a method setCurrentTimeout(int timeout) to the RetryPolicy and it's implementation in DefaultRetryPolicy.

Then I added a setCurrentTimeout(int timeout) in the Request class and called it .

This seems to do the job.

Sorry for my laziness by the way and hooray for open source.

What is the SQL command to return the field names of a table?

For IBM DB2 (will double check this on Monday to be sure.)

SELECT TABNAME,COLNAME from SYSCAT.COLUMNS where TABNAME='MYTABLE'

How to extract a value from a string using regex and a shell?

It seems that you are asking multiple things. To answer them:

Yes, it is ok to extract data from a string using regular expressions, that's what they're there for
You get errors, which one and what shell tool do you use?
You can extract the numbers by catching them in capturing parentheses:
```
.*(\d+) rofl.*
```
and using $1 to get the string out (.* is for "the rest before and after on the same line)

With sed as example, the idea becomes this to replace all strings in a file with only the matching number:

sed -e 's/.*(\d+) rofl.*/$1/g' inputFileName > outputFileName

or:

echo "12 BBQ ,45 rofl, 89 lol" | sed -e 's/.*(\d+) rofl.*/$1/g'

What is the del method, How to call it?

I wrote up the answer for another question, though this is a more accurate question for it.

How do constructors and destructors work?

Here is a slightly opinionated answer.

Don't use __del__. This is not C++ or a language built for destructors. The __del__ method really should be gone in Python 3.x, though I'm sure someone will find a use case that makes sense. If you need to use __del__, be aware of the basic limitations per http://docs.python.org/reference/datamodel.html:

__del__ is called when the garbage collector happens to be collecting the objects, not when you lose the last reference to an object and not when you execute del object.
__del__ is responsible for calling any __del__ in a superclass, though it is not clear if this is in method resolution order (MRO) or just calling each superclass.
Having a __del__ means that the garbage collector gives up on detecting and cleaning any cyclic links, such as losing the last reference to a linked list. You can get a list of the objects ignored from gc.garbage. You can sometimes use weak references to avoid the cycle altogether. This gets debated now and then: see http://mail.python.org/pipermail/python-ideas/2009-October/006194.html.
The __del__ function can cheat, saving a reference to an object, and stopping the garbage collection.
Exceptions explicitly raised in __del__ are ignored.
__del__ complements __new__ far more than __init__. This gets confusing. See http://www.algorithm.co.il/blogs/programming/python-gotchas-1-del-is-not-the-opposite-of-init/ for an explanation and gotchas.
__del__ is not a "well-loved" child in Python. You will notice that sys.exit() documentation does not specify if garbage is collected before exiting, and there are lots of odd issues. Calling the __del__ on globals causes odd ordering issues, e.g., http://bugs.python.org/issue5099. Should __del__ called even if the __init__ fails? See http://mail.python.org/pipermail/python-dev/2000-March/thread.html#2423 for a long thread.

But, on the other hand:

__del__ means you do not forget to call a close statement. See http://eli.thegreenplace.net/2009/06/12/safely-using-destructors-in-python/ for a pro __del__ viewpoint. This is usually about freeing ctypes or some other special resource.

And my pesonal reason for not liking the __del__ function.

Everytime someone brings up __del__ it devolves into thirty messages of confusion.
It breaks these items in the Zen of Python:
- Simple is better than complicated.
- Special cases aren't special enough to break the rules.
- Errors should never pass silently.
- In the face of ambiguity, refuse the temptation to guess.
- There should be one – and preferably only one – obvious way to do it.
- If the implementation is hard to explain, it's a bad idea.

So, find a reason not to use __del__.

Android dex gives a BufferOverflowException when building

For the ones facing issue with IntelliJ IDEA 13, uninstall Build Tools 19.

What are the dark corners of Vim your mom never told you about?

I'd like to arrange some of my own config files in after-directory. It's especially useful for ftplugin.

You can avoid to write a long list of augroup in your .vimrc file instead of separate files for each type.

But, obviously, .vim/ftplugin directory do the same thing as .vim/after/ftplugin, but I'd prefer to leave .vim directory to vim plugins.

Playing .mp3 and .wav in Java?

It's been a while since I used it, but JavaLayer is great for MP3 playback

android.view.InflateException: Binary XML file line #12: Error inflating class <unknown>

In my case I've to specify the complete package name of library UI component that I use in my layout file.

How to find whether a number belongs to a particular range in Python?

print 'yes' if 0 < x < 0.5 else 'no'

range() is for generating arrays of consecutive integers

HTML img align="middle" doesn't align an image

Change 'middle' to 'center'. Like so:

<img align="center" ....>

DropDownList in MVC 4 with Razor

You can use this:

@Html.DropDownListFor(x => x.Tipo, new List<SelectListItem>
    {
                        new SelectListItem() {Text = "Exemplo1", Value="Exemplo1"},
                        new SelectListItem() {Text = "Exemplo2", Value="Exemplo2"},
                        new SelectListItem() {Text = "Exemplo3", Value="Exemplo3"}
    })

Get key from a HashMap using the value

We can get KEY from VALUE. Below is a sample code_

 public class Main {
  public static void main(String[] args) {
    Map map = new HashMap();
    map.put("key_1","one");
    map.put("key_2","two");
    map.put("key_3","three");
    map.put("key_4","four");

    System.out.println(getKeyFromValue(map,"four"));
  }
  public static Object getKeyFromValue(Map hm, Object value) {
    for (Object o : hm.keySet()) {
      if (hm.get(o).equals(value)) {
        return o;
      }
    }
    return null;
  }
}

I hope this will help everyone.

Tkinter module not found on Ubuntu

What worked for me in Ubuntu was actually just:

sudo apt-get install python3-tk

For python 3.6:

sudo apt-get install python3.6-tk

I didn't read anywhere, I simply tried it, as onteria_'s method didn't seem to work for me.

How do I get a python program to do nothing?

You could use a pass statement:

if condition:
    pass

Python 2.x documentation

Python 3.x documentation

However I doubt you want to do this, unless you just need to put something in as a placeholder until you come back and write the actual code for the if statement.

If you have something like this:

if condition:        # condition in your case being `num2 == num5`
    pass
else:
    do_something()

You can in general change it to this:

if not condition:
    do_something()

But in this specific case you could (and should) do this:

if num2 != num5:        # != is the not-equal-to operator
    do_something()

How can I extract a good quality JPEG image from a video file with ffmpeg?

Output the images in a lossless format such as PNG:

ffmpeg.exe -i 10fps.h264 -r 10 -f image2 10fps.h264_%03d.png

Edit/Update: Not quite sure why I originally gave a strange filename example (with a possibly made-up extension).

I have since found that -vsync 0 is simpler than -r 10 because it avoids needing to know the frame rate.

This is something like what I currently use:
mkdir stills
ffmpeg -i my-film.mp4 -vsync 0 -f image2 stills/my-film-%06d.png
To extract only the key frames (which are likely to be of higher quality post-edit):
ffmpeg -skip_frame nokey -i my-film.mp4 -vsync 0 -f image2 stills/my-film-%06d.png

Then use another program (where you can more precisely specify quality, subsampling and DCT method – e.g. GIMP) to convert the PNGs you want to JPEG.

It is possible to obtain slightly sharper images in JPEG format this way than is possible with -qmin 1 -q:v 1 and outputting as JPEG directly from ffmpeg.

How to display an alert box from C# in ASP.NET?

After insertion code,

ScriptManager.RegisterClientScriptBlock(this, this.GetType(), "alertMessage", "alert('Record Inserted Successfully')", true);

Is there a way to use use text as the background with CSS?

Ciro's solution about an SVG Data URI background containing the text is very clever.

However, it won't work in IE if you just add the plain SVG source to the data URI.

In order to get around this and make it work in IE9 and up, encode the SVG to base64. This is a great tool.

So this:

background:url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg"><text x="5%" y="5%" font-size="30" fill="red">I love SVG!</text></svg>');

Becomes this:

background:url('data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjx0ZXh0IHg9IjUlIiB5PSI1JSIgZm9udC1zaXplPSIzMCIgZmlsbD0icmVkIj5JIGxvdmUgU1ZHITwvdGV4dD48L3N2Zz4=');

Tested and it works in IE9-10-11, WebKit (Chrome 37, Opera 23) and Gecko (Firefox 31).

http://jsfiddle.net/qapp5dLn/

What is the difference between persist() and merge() in JPA and Hibernate?

Persist should be called only on new entities, while merge is meant to reattach detached entities.

If you're using the assigned generator, using merge instead of persist can cause a redundant SQL statement.

Also, calling merge for managed entities is also a mistake since managed entities are automatically managed by Hibernate, and their state is synchronized with the database record by the dirty checking mechanism upon flushing the Persistence Context.

How to create and write to a txt file using VBA

To elaborate on Ben's answer:

If you add a reference to Microsoft Scripting Runtime and correctly type the variable fso you can take advantage of autocompletion (Intellisense) and discover the other great features of FileSystemObject.

Here is a complete example module:

Option Explicit

' Go to Tools -> References... and check "Microsoft Scripting Runtime" to be able to use
' the FileSystemObject which has many useful features for handling files and folders
Public Sub SaveTextToFile()

    Dim filePath As String
    filePath = "C:\temp\MyTestFile.txt"

    ' The advantage of correctly typing fso as FileSystemObject is to make autocompletion
    ' (Intellisense) work, which helps you avoid typos and lets you discover other useful
    ' methods of the FileSystemObject
    Dim fso As FileSystemObject
    Set fso = New FileSystemObject
    Dim fileStream As TextStream

    ' Here the actual file is created and opened for write access
    Set fileStream = fso.CreateTextFile(filePath)

    ' Write something to the file
    fileStream.WriteLine "something"

    ' Close it, so it is not locked anymore
    fileStream.Close

    ' Here is another great method of the FileSystemObject that checks if a file exists
    If fso.FileExists(filePath) Then
        MsgBox "Yay! The file was created! :D"
    End If

    ' Explicitly setting objects to Nothing should not be necessary in most cases, but if
    ' you're writing macros for Microsoft Access, you may want to uncomment the following
    ' two lines (see https://stackoverflow.com/a/517202/2822719 for details):
    'Set fileStream = Nothing
    'Set fso = Nothing

End Sub

How to check in Javascript if one element is contained within another

I came across a wonderful piece of code to check whether or not an element is a child of another element. I have to use this because IE doesn't support the .contains element method. Hope this will help others as well.

Below is the function:

function isChildOf(childObject, containerObject) {
  var returnValue = false;
  var currentObject;

  if (typeof containerObject === 'string') {
    containerObject = document.getElementById(containerObject);
  }
  if (typeof childObject === 'string') {
    childObject = document.getElementById(childObject);
  }

  currentObject = childObject.parentNode;

  while (currentObject !== undefined) {
    if (currentObject === document.body) {
      break;
    }

    if (currentObject.id == containerObject.id) {
      returnValue = true;
      break;
    }

    // Move up the hierarchy
    currentObject = currentObject.parentNode;
  }

  return returnValue;
}

How to list active / open connections in Oracle?

Select count(1) From V$session
where status='ACTIVE'
/

Random shuffling of an array

Look at the Collections class, specifically shuffle(...).

Android-Studio upgraded from 0.1.9 to 0.2.0 causing gradle build errors now

Basically if you follow the issues in this link for 0.2 you'll likely get yourself fixed, I had the same problems with 0.2

jQuery - Trigger event when an element is removed from the DOM

The "remove" event from jQuery works fine, without addition. It might be more reliable in time to use a simple trick, instead of patching jQuery.

Just modify or add an attribute in the element you are about to remove from the DOM. Thus, you can trigger any update function, that will just ignore elements on way to be destroyed, with the attribute "do_not_count_it".

Suppose we have a table with cells corresponding to prices, and that you need to show only the last price: This is the selector to trigger when a price cell is deleted (we have a button in each line of the table doing that, not shown here)

$('td[validity="count_it"]').on("remove", function () {
    $(this).attr("validity","do_not_count_it");
    update_prices();
});

And here is a function that finds the last price in the table, not taking account of the last one, if it was the one that was removed. Indeed, when the "remove" event is triggered, and when this function is called, the element is not removed yet.

function update_prices(){
      var mytable=$("#pricestable");
      var lastpricecell = mytable.find('td[validity="count_it"]').last();
}

In the end, the update_prices() function works fine, and after that, the DOM element is removed.

How do you get the list of targets in a makefile?

Plenty of workable solutions here, but as I like saying, "if it's worth doing once, it's worth doing again." I did upvote the sugestion to use (tab)(tab), but as some have noted, you may not have completion support, or, if you have many include files, you may want an easier way to know where a target is defined.

I have not tested the below with sub-makes...I think it wouldn't work. As we know, recursive makes considered harmful.

.PHONY: list ls
ls list :
    @# search all include files for targets.
    @# ... excluding special targets, and output dynamic rule definitions unresolved.
    @for inc in $(MAKEFILE_LIST); do \
    echo ' =' $$inc '= '; \
    grep -Eo '^[^\.#[:blank:]]+.*:.*' $$inc | grep -v ':=' | \
    cut -f 1 | sort | sed 's/.*/  &/' | sed -n 's/:.*$$//p' | \
    tr $$ \\\ | tr $(open_paren) % | tr $(close_paren) % \
; done

# to get around escaping limitations:
open_paren := \(
close_paren := \)

Which I like because:

list targets by include file.
output raw dynamic target definitions (replaces variable delimiters with modulo)
output each target on a new line
seems clearer (subjective opinion)

Explanation:

foreach file in the MAKEFILE_LIST
output the name of the file
grep lines containing a colon, that are not indented, not comments, and don't start with a period
exclude immediate assignment expressions (:=)
cut, sort, indent, and chop rule-dependencies (after colon)
munge variable delimiters to prevent expansion

Sample Output:

 = Makefile = 
  includes
  ls list
 = util/kiss/snapshots.mk = 
  rotate-db-snapshots
  rotate-file-snapshots
  snap-db
  snap-files
  snapshot
 = util/kiss/main.mk = 
  dirs
  install
   %MK_DIR_PREFIX%env-config.php
   %MK_DIR_PREFIX%../srdb

Performance of Arrays vs. Lists

Since I had a similar question this got me a fast start.

My question is a bit more specific, 'what is the fastest method for a reflexive array implementation'

The testing done by Marc Gravell shows a lot, but not exactly access timing. His timing include the looping over the array's and lists as well. Since I also came up with a third method that I wanted to test, a 'Dictionary', just to compare, I extended hist test code.

Firts, I do a test using a constant, which gives me a certain timing including the loop. This is a 'bare' timing, excluding the actual access. Then I do a test with accessing the subject structure, this gives me and 'overhead included' timing, looping and actual access.

The difference between 'bare' timing and 'overhead indluded' timing gives me an indication of the 'structure access' timing.

But how accurate is this timing? During the test windows will do some time slicing for shure. I have no information about the time slicing but I asume it is evenly distributed during the test and in the order of tens of msec which means that the accuracy for the timing should be in the order of +/- 100 msec or so. A bit rough estimate? Anyway a source of a systematic mearure error.

Also, the tests were done in 'Debug' mode with no optimalisation. Otherwise the compiler might change the actual test code.

So, I get two results, one for a constant, marked '(c)', and one for access marked '(n)' and the difference 'dt' tells me how much time the actual access takes.

And this are the results:

          Dictionary(c)/for: 1205ms (600000000)
          Dictionary(n)/for: 8046ms (589725196)
 dt = 6841

                List(c)/for: 1186ms (1189725196)
                List(n)/for: 2475ms (1779450392)
 dt = 1289

               Array(c)/for: 1019ms (600000000)
               Array(n)/for: 1266ms (589725196)
 dt = 247

 Dictionary[key](c)/foreach: 2738ms (600000000)
 Dictionary[key](n)/foreach: 10017ms (589725196)
 dt = 7279

            List(c)/foreach: 2480ms (600000000)
            List(n)/foreach: 2658ms (589725196)
 dt = 178

           Array(c)/foreach: 1300ms (600000000)
           Array(n)/foreach: 1592ms (589725196)
 dt = 292


 dt +/-.1 sec   for    foreach
 Dictionary     6.8       7.3
 List           1.3       0.2
 Array          0.2       0.3

 Same test, different system:
 dt +/- .1 sec  for    foreach
 Dictionary     14.4   12.0
       List      1.7    0.1
      Array      0.5    0.7

With better estimates on the timing errors (how to remove the systematic measurement error due to time slicing?) more could be said about the results.

It looks like List/foreach has the fastest access but the overhead is killing it.

The difference between List/for and List/foreach is stange. Maybe some cashing is involved?

Further, for access to an array it does not matter if you use a for loop or a foreach loop. The timing results and its accuracity makes the results 'comparible'.

Using a dictionary is by far the slowest, I only considered it because on the left side (the indexer) I have a sparse list of integers and not a range as is used in this tests.

Here is the modified test code.

Dictionary<int, int> dict = new Dictionary<int, int>(6000000);
List<int> list = new List<int>(6000000);
Random rand = new Random(12345);
for (int i = 0; i < 6000000; i++)
{
    int n = rand.Next(5000);
    dict.Add(i, n);
    list.Add(n);
}
int[] arr = list.ToArray();

int chk = 0;
Stopwatch watch = Stopwatch.StartNew();
for (int rpt = 0; rpt < 100; rpt++)
{
    int len = dict.Count;
    for (int i = 0; i < len; i++)
    {
        chk += 1; // dict[i];
    }
}
watch.Stop();
long c_dt = watch.ElapsedMilliseconds;
Console.WriteLine("         Dictionary(c)/for: {0}ms ({1})", c_dt, chk);

chk = 0;
watch = Stopwatch.StartNew();
for (int rpt = 0; rpt < 100; rpt++)
{
    int len = dict.Count;
    for (int i = 0; i < len; i++)
    {
        chk += dict[i];
    }
}
watch.Stop();
long n_dt = watch.ElapsedMilliseconds;
Console.WriteLine("         Dictionary(n)/for: {0}ms ({1})", n_dt, chk);
Console.WriteLine("dt = {0}", n_dt - c_dt);

watch = Stopwatch.StartNew();
for (int rpt = 0; rpt < 100; rpt++)
{
    int len = list.Count;
    for (int i = 0; i < len; i++)
    {
        chk += 1; // list[i];
    }
}
watch.Stop();
c_dt = watch.ElapsedMilliseconds;
Console.WriteLine("               List(c)/for: {0}ms ({1})", c_dt, chk);

watch = Stopwatch.StartNew();
for (int rpt = 0; rpt < 100; rpt++)
{
    int len = list.Count;
    for (int i = 0; i < len; i++)
    {
        chk += list[i];
    }
}
watch.Stop();
n_dt = watch.ElapsedMilliseconds;
Console.WriteLine("               List(n)/for: {0}ms ({1})", n_dt, chk);
Console.WriteLine("dt = {0}", n_dt - c_dt);

chk = 0;
watch = Stopwatch.StartNew();
for (int rpt = 0; rpt < 100; rpt++)
{
    for (int i = 0; i < arr.Length; i++)
    {
        chk += 1; // arr[i];
    }
}
watch.Stop();
c_dt = watch.ElapsedMilliseconds;
Console.WriteLine("              Array(c)/for: {0}ms ({1})", c_dt, chk);

chk = 0;
watch = Stopwatch.StartNew();
for (int rpt = 0; rpt < 100; rpt++)
{
    for (int i = 0; i < arr.Length; i++)
    {
        chk += arr[i];
    }
}
watch.Stop();
n_dt = watch.ElapsedMilliseconds;
Console.WriteLine("Array(n)/for: {0}ms ({1})", n_dt, chk);
Console.WriteLine("dt = {0}", n_dt - c_dt);

chk = 0;
watch = Stopwatch.StartNew();
for (int rpt = 0; rpt < 100; rpt++)
{
    foreach (int i in dict.Keys)
    {
        chk += 1; // dict[i]; ;
    }
}
watch.Stop();
c_dt = watch.ElapsedMilliseconds;
Console.WriteLine("Dictionary[key](c)/foreach: {0}ms ({1})", c_dt, chk);

chk = 0;
watch = Stopwatch.StartNew();
for (int rpt = 0; rpt < 100; rpt++)
{
    foreach (int i in dict.Keys)
    {
        chk += dict[i]; ;
    }
}
watch.Stop();
n_dt = watch.ElapsedMilliseconds;
Console.WriteLine("Dictionary[key](n)/foreach: {0}ms ({1})", n_dt, chk);
Console.WriteLine("dt = {0}", n_dt - c_dt);

chk = 0;
watch = Stopwatch.StartNew();
for (int rpt = 0; rpt < 100; rpt++)
{
    foreach (int i in list)
    {
        chk += 1; // i;
    }
}
watch.Stop();
c_dt = watch.ElapsedMilliseconds;
Console.WriteLine("           List(c)/foreach: {0}ms ({1})", c_dt, chk);

chk = 0;
watch = Stopwatch.StartNew();
for (int rpt = 0; rpt < 100; rpt++)
{
    foreach (int i in list)
    {
        chk += i;
    }
}
watch.Stop();
n_dt = watch.ElapsedMilliseconds;
Console.WriteLine("           List(n)/foreach: {0}ms ({1})", n_dt, chk);
Console.WriteLine("dt = {0}", n_dt - c_dt);

chk = 0;
watch = Stopwatch.StartNew();
for (int rpt = 0; rpt < 100; rpt++)
{
    foreach (int i in arr)
    {
        chk += 1; // i;
    }
}
watch.Stop();
c_dt = watch.ElapsedMilliseconds;
Console.WriteLine("          Array(c)/foreach: {0}ms ({1})", c_dt, chk);

chk = 0;
watch = Stopwatch.StartNew();
for (int rpt = 0; rpt < 100; rpt++)
{
    foreach (int i in arr)
    {
        chk += i;
    }
}
watch.Stop();
n_dt = watch.ElapsedMilliseconds;
Console.WriteLine("Array(n)/foreach: {0}ms ({1})", n_dt, chk);
Console.WriteLine("dt = {0}", n_dt - c_dt);

Django development IDE

Ulipad is a good one. http://code.google.com/p/ulipad/

How to detect if numpy is installed

In the numpy README.txt file, it says

After installation, tests can be run with:

python -c 'import numpy; numpy.test()'

This should be a sufficient test for proper installation.

Git: How to check if a local repo is up to date?

you can use git status -uno to check if your local branch is up-to-date with the origin one.

How to escape double quotes in JSON

Try this:

"maingame": {
  "day1": {
    "text1": "Tag 1",
     "text2": "Heute startet unsere Rundreise \" Example text\". Jeden Tag wird ein neues Reiseziel angesteuert bis wir.</strong> "
  }
}

(just one backslash (\) in front of quotes).

C - determine if a number is prime

After reading this question, I was intrigued by the fact that some answers offered optimization by running a loop with multiples of 2*3=6.

So I create a new function with the same idea, but with multiples of 2*3*5=30.

int check235(unsigned long n)
{
    unsigned long sq, i;

    if(n<=3||n==5)
        return n>1;

    if(n%2==0 || n%3==0 || n%5==0)
        return 0;

    if(n<=30)
        return checkprime(n); /* use another simplified function */

    sq=ceil(sqrt(n));
    for(i=7; i<=sq; i+=30)
        if (n%i==0 || n%(i+4)==0 || n%(i+6)==0 || n%(i+10)==0 || n%(i+12)==0 
           || n%(i+16)==0 || n%(i+22)==0 || n%(i+24)==0)
            return 0;

        return 1;
}

By running both functions and checking times I could state that this function is really faster. Lets see 2 tests with 2 different primes:

$ time ./testprimebool.x 18446744069414584321 0
f(2,3)
Yes, its prime.    
real    0m14.090s
user    0m14.096s
sys     0m0.000s

$ time ./testprimebool.x 18446744069414584321 1
f(2,3,5)
Yes, its prime.    
real    0m9.961s
user    0m9.964s
sys     0m0.000s

$ time ./testprimebool.x 18446744065119617029 0
f(2,3)
Yes, its prime.    
real    0m13.990s
user    0m13.996s
sys     0m0.004s

$ time ./testprimebool.x 18446744065119617029 1
f(2,3,5)
Yes, its prime.    
real    0m10.077s
user    0m10.068s
sys     0m0.004s

So I thought, would someone gain too much if generalized? I came up with a function that will do a siege first to clean a given list of primordial primes, and then use this list to calculate the bigger one.

int checkn(unsigned long n, unsigned long *p, unsigned long t)
{
    unsigned long sq, i, j, qt=1, rt=0;
    unsigned long *q, *r;

    if(n<2)
        return 0;

    for(i=0; i<t; i++)
    {
        if(n%p[i]==0)
            return 0;
        qt*=p[i];
    }
    qt--;

    if(n<=qt)
        return checkprime(n); /* use another simplified function */

    if((q=calloc(qt, sizeof(unsigned long)))==NULL)
    {
        perror("q=calloc()");
        exit(1);
    }
    for(i=0; i<t; i++)
        for(j=p[i]-2; j<qt; j+=p[i])
            q[j]=1;

    for(j=0; j<qt; j++)
        if(q[j])
            rt++;

    rt=qt-rt;
    if((r=malloc(sizeof(unsigned long)*rt))==NULL)
    {
        perror("r=malloc()");
        exit(1);
    }
    i=0;
    for(j=0; j<qt; j++)
        if(!q[j])
            r[i++]=j+1;

    free(q);

    sq=ceil(sqrt(n));
    for(i=1; i<=sq; i+=qt+1)
    {
        if(i!=1 && n%i==0)
            return 0;
        for(j=0; j<rt; j++)
            if(n%(i+r[j])==0)
                return 0;
    }
    return 1;
}

I assume I did not optimize the code, but it's fair. Now, the tests. Because so many dynamic memory, I expected the list 2 3 5 to be a little slower than the 2 3 5 hard-coded. But it was ok as you can see bellow. After that, time got smaller and smaller, culminating the best list to be:

2 3 5 7 11 13 17 19

With 8.6 seconds. So if someone would create a hardcoded program that makes use of such technique I would suggest use the list 2 3 and 5, because the gain is not that big. But also, if willing to code, this list is ok. Problem is you cannot state all cases without a loop, or your code would be very big (There would be 1658879 ORs, that is || in the respective internal if). The next list:

2 3 5 7 11 13 17 19 23

time started to get bigger, with 13 seconds. Here the whole test:

$ time ./testprimebool.x 18446744065119617029 2 3 5
f(2,3,5)
Yes, its prime.
real    0m12.668s
user    0m12.680s
sys     0m0.000s

$ time ./testprimebool.x 18446744065119617029 2 3 5 7
f(2,3,5,7)
Yes, its prime.
real    0m10.889s
user    0m10.900s
sys     0m0.000s

$ time ./testprimebool.x 18446744065119617029 2 3 5 7 11
f(2,3,5,7,11)
Yes, its prime.
real    0m10.021s
user    0m10.028s
sys     0m0.000s

$ time ./testprimebool.x 18446744065119617029 2 3 5 7 11 13
f(2,3,5,7,11,13)
Yes, its prime.
real    0m9.351s
user    0m9.356s
sys     0m0.004s

$ time ./testprimebool.x 18446744065119617029 2 3 5 7 11 13 17
f(2,3,5,7,11,13,17)
Yes, its prime.
real    0m8.802s
user    0m8.800s
sys     0m0.008s

$ time ./testprimebool.x 18446744065119617029 2 3 5 7 11 13 17 19
f(2,3,5,7,11,13,17,19)
Yes, its prime.
real    0m8.614s
user    0m8.564s
sys     0m0.052s

$ time ./testprimebool.x 18446744065119617029 2 3 5 7 11 13 17 19 23
f(2,3,5,7,11,13,17,19,23)
Yes, its prime.
real    0m13.013s
user    0m12.520s
sys     0m0.504s

$ time ./testprimebool.x 18446744065119617029 2 3 5 7 11 13 17 19 23 29
f(2,3,5,7,11,13,17,19,23,29)                                                                                                                         
q=calloc(): Cannot allocate memory

PS. I did not free(r) intentionally, giving this task to the OS, as the memory would be freed as soon as the program exited, to gain some time. But it would be wise to free it if you intend to keep running your code after the calculation.

BONUS

int check2357(unsigned long n)
{
    unsigned long sq, i;

    if(n<=3||n==5||n==7)
        return n>1;

    if(n%2==0 || n%3==0 || n%5==0 || n%7==0)
        return 0;

    if(n<=210)
        return checkprime(n); /* use another simplified function */

    sq=ceil(sqrt(n));
    for(i=11; i<=sq; i+=210)
    {    
        if(n%i==0 || n%(i+2)==0 || n%(i+6)==0 || n%(i+8)==0 || n%(i+12)==0 || 
   n%(i+18)==0 || n%(i+20)==0 || n%(i+26)==0 || n%(i+30)==0 || n%(i+32)==0 || 
   n%(i+36)==0 || n%(i+42)==0 || n%(i+48)==0 || n%(i+50)==0 || n%(i+56)==0 || 
   n%(i+60)==0 || n%(i+62)==0 || n%(i+68)==0 || n%(i+72)==0 || n%(i+78)==0 || 
   n%(i+86)==0 || n%(i+90)==0 || n%(i+92)==0 || n%(i+96)==0 || n%(i+98)==0 || 
   n%(i+102)==0 || n%(i+110)==0 || n%(i+116)==0 || n%(i+120)==0 || n%(i+126)==0 || 
   n%(i+128)==0 || n%(i+132)==0 || n%(i+138)==0 || n%(i+140)==0 || n%(i+146)==0 || 
   n%(i+152)==0 || n%(i+156)==0 || n%(i+158)==0 || n%(i+162)==0 || n%(i+168)==0 || 
   n%(i+170)==0 || n%(i+176)==0 || n%(i+180)==0 || n%(i+182)==0 || n%(i+186)==0 || 
   n%(i+188)==0 || n%(i+198)==0)
            return 0;
    }
    return 1;
}

Time:

$ time ./testprimebool.x 18446744065119617029 7
h(2,3,5,7)
Yes, its prime.
real    0m9.123s
user    0m9.132s
sys     0m0.000s

preg_match(); - Unknown modifier '+'

You need to use delimiters with regexes in PHP. You can use the often used /, but PHP lets you use any matching characters, so @ and # are popular.

Can you pass parameters to an AngularJS controller on creation?

Like @akonsu and Nigel Findlater suggest, you can read the url where url is index.html#/user/:id with $routeParams.id and use it inside the controller.

your app:

var app = angular.module('myApp', [ 'ngResource' ]);

app.config(['$routeProvider', function($routeProvider) {
    $routeProvider.when('/:type/:id', {templateUrl: 'myView.html', controller: 'myCtrl'});
}]);

the resource service

app.factory('MyElements', ['$resource', function($resource) {
     return $resource('url/to/json/:type/:id', { type:'@type', id:'@id' });
}]);

the controller

app.controller('MyCtrl', ['$scope', '$routeParams', 'MyElements', function($scope, $routeParams, MyElements) {
    MyElements.get({'type': $routeParams.type, "id": $routeParams.id }, function(elm) {
        $scope.elm = elm;
    })
}]);

then, elm is accessible in the view depending on the id.

How to update one file in a zip archive

From zip(1):

When given the name of an existing zip archive, zip will replace identically named entries in the zip archive or add entries for new names.

So just use the zip command as you normally would to create a new .zip file containing only that one file, except the .zip filename you specify will be the existing archive.

How to parse XML and count instances of a particular node attribute?

A new lib, I fell in love with it after I used it. I recommend it to you.

from simplified_scrapy import SimplifiedDoc
xml = '''
<foo>
   <bar>
      <type foobar="1"/>
      <type foobar="2"/>
   </bar>
</foo>
'''

doc = SimplifiedDoc(xml)
types = doc.selects('bar>type')
print (len(types)) # 2
print (types.foobar) # ['1', '2']
print (doc.selects('bar>type>foobar()')) # ['1', '2']

Here are more examples. This lib is easy to use.

Why is String immutable in Java?

String class is FINAL it mean you can't create any class to inherit it and change the basic structure and make the Sting mutable.

Another thing instance variable and methods of String class that are provided are such that you can't change String object once created.

The reason what you have added doesn't make the String immutable at all.This all says how the String is stored in heap.Also string pool make the huge difference in performance

Firefox "ssl_error_no_cypher_overlap" error

"Error code: ssl_error_no_cypher_overlap" error message after login, when Welcome screen expected--using Firefox browser

Solution

Enable support for 40-bit RSA encryption in the Firefox Browser: 1: enter 'about:config' in Browser Address bar 2: find/select "security.ssl3.rsa_rc4_40_md5" 3: set boolean to TRUE

jQuery date formatting

Simply we can format the date like,

var month = date.getMonth() + 1;
var day = date.getDate();
var date1 = (('' + day).length < 2 ? '0' : '') + day + '/' + (('' + month).length < 2 ? '0' : '') + month + '/' + date.getFullYear();
$("#txtDate").val($.datepicker.formatDate('dd/mm/yy', new Date(date1)));

Where "date" is a date in any format.

Program to find largest and smallest among 5 numbers without using array

You could use list (or vector), which is not an array:

#include<list>
#include<algorithm>
#include<iostream>
using namespace std;
int main()
{
    list<int> l;
    l.push_back(3); 
    l.push_back(9); 
    l.push_back(30);    
    l.push_back(0); 
    l.push_back(5); 

    list<int>::iterator it_max = max_element(l.begin(), l.end());
    list<int>::iterator it_min = min_element(l.begin(), l.end());

    cout << "Max: " << *it_max << endl;
    cout << "Min: " << *it_min << endl;
}

How does the @property decorator work in Python?

A property can be declared in two ways.

Creating the getter, setter methods for an attribute and then passing these as argument to property function
Using the @property decorator.

You can have a look at few examples I have written about properties in python.

Can't connect to local MySQL server through socket '/tmp/mysql.sock

For me the problem was I wasn't running MySQL Server. Run server first and then execute mysql.

$ mysql.server start
$ mysql -h localhost -u root -p

How to reverse MD5 to get the original string?

Its not possible thats the whole point of hashing. You can however bruteforce by going through all possibilities (using all possible digits characters in every possible order) and hashing them and checking for a collision.

for more information on hashing and MD5 etc see: http://en.wikipedia.org/wiki/MD5 , http://en.wikipedia.org/wiki/Hash_function , http://en.wikipedia.org/wiki/Cryptographic_hash_function and http://onin.com/hhh/hhhexpl.html

I myself created my own app to do this, its open source you can check the link: http://sourceforge.net/projects/jpassrecovery/ and of course the source. Here is the source for easy access it has a basic implementation in the comments:

Bruter.java:

import java.util.ArrayList;

public class Bruter {

    public ArrayList<String> characters = new ArrayList<>();
    public boolean found = false;
    public int maxLength;
    public int minLength;
    public int count;
    long starttime, endtime;
    public int minutes, seconds, hours, days;
    public char[] specialCharacters = {'~', '`', '!', '@', '#', '$', '%', '^',
        '&', '*', '(', ')', '_', '-', '+', '=', '{', '}', '[', ']', '|', '\\',
        ';', ':', '\'', '"', '<', '.', ',', '>', '/', '?', ' '};
    public boolean done = false;
    public boolean paused = false;

    public boolean isFound() {
        return found;
    }

    public void setPaused(boolean paused) {
        this.paused = paused;
    }

    public boolean isPaused() {
        return paused;
    }

    public void setFound(boolean found) {
        this.found = found;
    }

    public synchronized void setEndtime(long endtime) {
        this.endtime = endtime;
    }

    public int getCounter() {
        return count;
    }

    public long getRemainder() {
        return getNumberOfPossibilities() - count;
    }

    public long getNumberOfPossibilities() {
        long possibilities = 0;
        for (int i = minLength; i <= maxLength; i++) {
            possibilities += (long) Math.pow(characters.size(), i);
        }
        return possibilities;
    }

    public void addExtendedSet() {
        for (char c = (char) 0; c <= (char) 31; c++) {
            characters.add(String.valueOf(c));
        }
    }

    public void addStandardCharacterSet() {
        for (char c = (char) 32; c <= (char) 127; c++) {
            characters.add(String.valueOf(c));
        }
    }

    public void addLowerCaseLetters() {
        for (char c = 'a'; c <= 'z'; c++) {
            characters.add(String.valueOf(c));
        }
    }

    public void addDigits() {
        for (int c = 0; c <= 9; c++) {
            characters.add(String.valueOf(c));
        }
    }

    public void addUpperCaseLetters() {
        for (char c = 'A'; c <= 'Z'; c++) {
            characters.add(String.valueOf(c));
        }
    }

    public void addSpecialCharacters() {
        for (char c : specialCharacters) {
            characters.add(String.valueOf(c));
        }
    }

    public void setMaxLength(int i) {
        maxLength = i;
    }

    public void setMinLength(int i) {
        minLength = i;
    }

    public int getPerSecond() {
        int i;
        try {
            i = (int) (getCounter() / calculateTimeDifference());
        } catch (Exception ex) {
            return 0;
        }
        return i;

    }

    public String calculateTimeElapsed() {
        long timeTaken = calculateTimeDifference();
        seconds = (int) timeTaken;
        if (seconds > 60) {
            minutes = (int) (seconds / 60);
            if (minutes * 60 > seconds) {
                minutes = minutes - 1;
            }

            if (minutes > 60) {
                hours = (int) minutes / 60;
                if (hours * 60 > minutes) {
                    hours = hours - 1;
                }
            }

            if (hours > 24) {
                days = (int) hours / 24;
                if (days * 24 > hours) {
                    days = days - 1;
                }
            }
            seconds -= (minutes * 60);
            minutes -= (hours * 60);
            hours -= (days * 24);
            days -= (hours * 24);
        }
        return "Time elapsed: " + days + "days " + hours + "h " + minutes + "min " + seconds + "s";
    }

    private long calculateTimeDifference() {
        long timeTaken = (long) ((endtime - starttime) * (1 * Math.pow(10, -9)));
        return timeTaken;
    }

    public boolean excludeChars(String s) {
        char[] arrayChars = s.toCharArray();
        for (int i = 0; i < arrayChars.length; i++) {
            characters.remove(arrayChars[i] + "");
        }
        if (characters.size() < maxLength) {
            return false;
        } else {
            return true;

        }
    }

    public int getMaxLength() {
        return maxLength;
    }

    public int getMinLength() {
        return minLength;
    }

    public void setIsDone(Boolean b) {
        done = b;
    }

    public boolean isDone() {
        return done;
    }
}

HashBruter.java:

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.zip.Adler32;
import java.util.zip.CRC32;
import java.util.zip.Checksum;
import javax.swing.JOptionPane;

public class HashBruter extends Bruter {
    /*
     * public static void main(String[] args) {
     *
     * final HashBruter hb = new HashBruter();
     *
     * hb.setMaxLength(5); hb.setMinLength(1);
     *
     * hb.addSpecialCharacters(); hb.addUpperCaseLetters();
     * hb.addLowerCaseLetters(); hb.addDigits();
     *
     * hb.setType("sha-512");
     *
     * hb.setHash("282154720ABD4FA76AD7CD5F8806AA8A19AEFB6D10042B0D57A311B86087DE4DE3186A92019D6EE51035106EE088DC6007BEB7BE46994D1463999968FBE9760E");
     *
     * Thread thread = new Thread(new Runnable() {
     *
     * @Override public void run() { hb.tryBruteForce(); } });
     *
     * thread.start();
     *
     * while (!hb.isFound()) { System.out.println("Hash: " +
     * hb.getGeneratedHash()); System.out.println("Number of Possibilities: " +
     * hb.getNumberOfPossibilities()); System.out.println("Checked hashes: " +
     * hb.getCounter()); System.out.println("Estimated hashes left: " +
     * hb.getRemainder()); }
     *
     * System.out.println("Found " + hb.getType() + " hash collision: " +
     * hb.getGeneratedHash() + " password is: " + hb.getPassword());
     *
     * }
     */

    public String hash, generatedHash, password;
    public String type;

    public String getType() {
        return type;
    }

    public String getPassword() {
        return password;
    }

    public void setHash(String p) {
        hash = p;
    }

    public void setType(String digestType) {
        type = digestType;
    }

    public String getGeneratedHash() {
        return generatedHash;
    }

    public void tryBruteForce() {
        starttime = System.nanoTime();
        for (int size = minLength; size <= maxLength; size++) {
            if (found == true || done == true) {
                break;
            } else {
                while (paused) {
                    try {
                        Thread.sleep(500);
                    } catch (InterruptedException ex) {
                        ex.printStackTrace();
                    }
                }
                generateAllPossibleCombinations("", size);
            }
        }
        done = true;
    }

    private void generateAllPossibleCombinations(String baseString, int length) {
        while (paused) {
            try {
                Thread.sleep(500);
            } catch (InterruptedException ex) {
                ex.printStackTrace();
            }
        }
        if (found == false || done == false) {
            if (baseString.length() == length) {
                if(type.equalsIgnoreCase("crc32")) {
                generatedHash = generateCRC32(baseString);
                } else if(type.equalsIgnoreCase("adler32")) {
                generatedHash = generateAdler32(baseString);
                } else if(type.equalsIgnoreCase("crc16")) {
                    generatedHash=generateCRC16(baseString);
                } else if(type.equalsIgnoreCase("crc64")) {
                    generatedHash=generateCRC64(baseString.getBytes());
                }
                else {
                generatedHash = generateHash(baseString.toCharArray());
                }
                    password = baseString;
                if (hash.equals(generatedHash)) {
                    password = baseString;
                    found = true;
                    done = true;
                }
                count++;
            } else if (baseString.length() < length) {
                for (int n = 0; n < characters.size(); n++) {
                    generateAllPossibleCombinations(baseString + characters.get(n), length);
                }
            }
        }
    }

    private String generateHash(char[] passwordChar) {
        MessageDigest md = null;
        try {
            md = MessageDigest.getInstance(type);
        } catch (NoSuchAlgorithmException e1) {
            JOptionPane.showMessageDialog(null, "No such algorithm for hashes exists", "Error", JOptionPane.ERROR_MESSAGE);
        }
        String passwordString = new String(passwordChar);
        byte[] passwordByte = passwordString.getBytes();
        md.update(passwordByte, 0, passwordByte.length);
        byte[] encodedPassword = md.digest();
        String encodedPasswordInString = toHexString(encodedPassword);
        return encodedPasswordInString;
    }

    private void byte2hex(byte b, StringBuffer buf) {
        char[] hexChars = {'0', '1', '2', '3', '4', '5', '6', '7', '8',
            '9', 'A', 'B', 'C', 'D', 'E', 'F'};
        int high = ((b & 0xf0) >> 4);
        int low = (b & 0x0f);
        buf.append(hexChars[high]);
        buf.append(hexChars[low]);
    }

    private String toHexString(byte[] block) {
        StringBuffer buf = new StringBuffer();
        int len = block.length;
        for (int i = 0; i < len; i++) {
            byte2hex(block[i], buf);
        }
        return buf.toString();
    }

    private String generateCRC32(String baseString) {

                //Convert string to bytes
                byte bytes[] = baseString.getBytes();

                Checksum checksum = new CRC32();

                /*
                 * To compute the CRC32 checksum for byte array, use
                 *
                 * void update(bytes[] b, int start, int length)
                 * method of CRC32 class.
                 */

                checksum.update(bytes,0,bytes.length);

                /*
                 * Get the generated checksum using
                 * getValue method of CRC32 class.
                 */
                return String.valueOf(checksum.getValue());
    }   
    private String generateAdler32(String baseString) {

                //Convert string to bytes
                byte bytes[] = baseString.getBytes();

                Checksum checksum = new Adler32();

                /*
                 * To compute the CRC32 checksum for byte array, use
                 *
                 * void update(bytes[] b, int start, int length)
                 * method of CRC32 class.
                 */

                checksum.update(bytes,0,bytes.length);

                /*
                 * Get the generated checksum using
                 * getValue method of CRC32 class.
                 */
                return String.valueOf(checksum.getValue());
    }
/*************************************************************************
 *  Compilation:  javac CRC16.java
 *  Execution:    java CRC16 s
 *  
 *  Reads in a string s as a command-line argument, and prints out
 *  its 16-bit Cyclic Redundancy Check (CRC16). Uses a lookup table.
 *
 *  Reference:  http://www.gelato.unsw.edu.au/lxr/source/lib/crc16.c
 *
 *  % java CRC16 123456789
 *  CRC16 = bb3d
 *
 * Uses irreducible polynomial:  1 + x^2 + x^15 + x^16
 *
 *
 *************************************************************************/
    private String generateCRC16(String baseString) {
                int[] table = {
            0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241,
            0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440,
            0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40,
            0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841,
            0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40,
            0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41,
            0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641,
            0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040,
            0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240,
            0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441,
            0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41,
            0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840,
            0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41,
            0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40,
            0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640,
            0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041,
            0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240,
            0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441,
            0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41,
            0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840,
            0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41,
            0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40,
            0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640,
            0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041,
            0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241,
            0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440,
            0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40,
            0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841,
            0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40,
            0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41,
            0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641,
            0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040,
        };


        byte[] bytes = baseString.getBytes();
        int crc = 0x0000;
        for (byte b : bytes) {
            crc = (crc >>> 8) ^ table[(crc ^ b) & 0xff];
        }

        return Integer.toHexString(crc);
    }
    /*******************************************************************************
 * Copyright (c) 2009, 2012 Mountainminds GmbH & Co. KG and Contributors
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Marc R. Hoffmann - initial API and implementation
 *    
 *******************************************************************************/

/**
 * CRC64 checksum calculator based on the polynom specified in ISO 3309. The
 * implementation is based on the following publications:
 * 
 * <ul>
 * <li>http://en.wikipedia.org/wiki/Cyclic_redundancy_check</li>
 * <li>http://www.geocities.com/SiliconValley/Pines/8659/crc.htm</li>
 * </ul>
 */
    private static final long POLY64REV = 0xd800000000000000L;

    private static final long[] LOOKUPTABLE;

    static {
        LOOKUPTABLE = new long[0x100];
        for (int i = 0; i < 0x100; i++) {
            long v = i;
            for (int j = 0; j < 8; j++) {
                if ((v & 1) == 1) {
                    v = (v >>> 1) ^ POLY64REV;
                } else {
                    v = (v >>> 1);
                }
            }
            LOOKUPTABLE[i] = v;
        }
    }

    /**
     * Calculates the CRC64 checksum for the given data array.
     * 
     * @param data
     *            data to calculate checksum for
     * @return checksum value
     */
    public static String generateCRC64(final byte[] data) {
        long sum = 0;
        for (int i = 0; i < data.length; i++) {
            final int lookupidx = ((int) sum ^ data[i]) & 0xff;
            sum = (sum >>> 8) ^ LOOKUPTABLE[lookupidx];
        }
        return String.valueOf(sum);
    }
}

you would use it like:

      final HashBruter hb = new HashBruter();

      hb.setMaxLength(5); hb.setMinLength(1);

     hb.addSpecialCharacters(); hb.addUpperCaseLetters();
     hb.addLowerCaseLetters(); hb.addDigits();

      hb.setType("sha-512");

                   hb.setHash("282154720ABD4FA76AD7CD5F8806AA8A19AEFB6D10042B0D57A311B86087DE4DE3186A92019D6EE51035106EE088DC6007BEB7BE46994D1463999968FBE9760E");

      Thread thread = new Thread(new Runnable() {

      @Override public void run() { hb.tryBruteForce(); } });

      thread.start();

      while (!hb.isFound()) { System.out.println("Hash: " +
      hb.getGeneratedHash()); System.out.println("Number of Possibilities: " +
      hb.getNumberOfPossibilities()); System.out.println("Checked hashes: " +
     hb.getCounter()); System.out.println("Estimated hashes left: " +
     hb.getRemainder()); }

     System.out.println("Found " + hb.getType() + " hash collision: " +
     hb.getGeneratedHash() + " password is: " + hb.getPassword());

Changing datagridview cell color dynamically

If you want every cell in the grid to have the same background color, you can just do this:

dataGridView1.DefaultCellStyle.BackColor = Color.Green;

Clear ComboBox selected text

Try specifying the actual index of the item you want erase the text from and set it's Text equal to "".

myComboBox[this.SelectedIndex].Text = ""

myComboBox.selectedIndex.Text = ""

I don't remember the exact syntax but it's something along those lines.

Is it possible to find out the users who have checked out my project on GitHub?

Go to the traffic section inside graphs. Here you can find how many unique visitors you have. Other than this there is no other way to know who exactly viewed your account.

Windows error 2 occured while loading the Java VM

I had same mistake, it was produced because i had disabled the creation of "_jvm" in the InstallAnywhere (project - JVM settings - Installer Settings - Bundled/Downloaded Virtual Machine), then into file "Uninstall $PRODUCT_NAME$.lax" into uninstall folder, the variable "lax.nl.current.vm" is empty.

If you don't need jvm is disabled check "Install Bundled / Downloaded Virtual Machine" option in the checkbox (project - JVM settings - Installer Settings - Bundled/Downloaded Virtual Machine).

If you need jvm is disabled because you create it manually, then you can do the following: create an action "Modify Text File" to append variable with the value of the _jvm folder.

(Existing File)
$USER_INSTALL_DIR$\Uninstall_$PRODUCT_NAME$ \Uninstall $PRODUCT_NAME$.lax

(Append)

lax.nl.current.vm=..\_jvm\bin\java.exe

Find value in an array

I know this question has already been answered, but I came here looking for a way to filter elements in an Array based on some criteria. So here is my solution example: using select, I find all constants in Class that start with "RUBY_"

Class.constants.select {|c| c.to_s =~ /^RUBY_/ }

UPDATE: In the meantime I have discovered that Array#grep works much better. For the above example,

Class.constants.grep /^RUBY_/

did the trick.

Spring Boot - Handle to Hibernate SessionFactory

If it's really required to access SessionFactory through @Autowire, I'd rather configure another EntityManagerFactory and then use it to configure the SessionFactory bean, like following:

@Configuration
public class SessionFactoryConfig {

@Autowired 
DataSource dataSource;

@Autowired
JpaVendorAdapter jpaVendorAdapter;

@Bean
@Primary
public EntityManagerFactory entityManagerFactory() {
    LocalContainerEntityManagerFactoryBean emf = new LocalContainerEntityManagerFactoryBean();
    emf.setDataSource(dataSource);
    emf.setJpaVendorAdapter(jpaVendorAdapter);
    emf.setPackagesToScan("com.hibernateLearning");
    emf.setPersistenceUnitName("default");
    emf.afterPropertiesSet();
    return emf.getObject();
}

@Bean
public SessionFactory setSessionFactory(EntityManagerFactory entityManagerFactory) {
    return entityManagerFactory.unwrap(SessionFactory.class);
} }

pythonw.exe or python.exe?

If you don't want a terminal window to pop up when you run your program, use pythonw.exe;
Otherwise, use python.exe

Regarding the syntax error: print is now a function in 3.x
So use instead:

print("a")

SQL LEFT-JOIN on 2 fields for MySQL

select a.ip, a.os, a.hostname, a.port, a.protocol,
       b.state
from a
left join b on a.ip = b.ip 
           and a.port = b.port

sklearn plot confusion matrix with labels

UPDATE:

In scikit-learn 0.22, there's a new feature to plot the confusion matrix directly.

See the documentation: sklearn.metrics.plot_confusion_matrix

OLD ANSWER:

I think it's worth mentioning the use of seaborn.heatmap here.

import seaborn as sns
import matplotlib.pyplot as plt     

ax= plt.subplot()
sns.heatmap(cm, annot=True, ax = ax); #annot=True to annotate cells

# labels, title and ticks
ax.set_xlabel('Predicted labels');ax.set_ylabel('True labels'); 
ax.set_title('Confusion Matrix'); 
ax.xaxis.set_ticklabels(['business', 'health']); ax.yaxis.set_ticklabels(['health', 'business']);

How to reload page every 5 seconds?

There's an automatic refresh-on-change tool for IE. It's called ReloadIt, and is available at http://reloadit.codeplex.com . Free.

You choose a URL that you'd like to auto-reload, and specify one or more directory paths to monitor for changes. Press F12 to start monitoring.

enter image description here

After you set it, minimize it. Then edit your content files. When you save any change, the page gets reloaded. like this:

enter image description here

Simple. easy.

How do I check in python if an element of a list is empty?

I got around this with len() and a simple if/else statement.

List elements will come back as an integer when wrapped in len() (1 for present, 0 for absent)

l = []

print(len(l)) # Prints 0

if len(l) == 0:
    print("Element is empty")
else:
    print("Element is NOT empty")

Output:

Element is empty

Best way to check if a URL is valid

You can use a native Filter Validator

filter_var($url, FILTER_VALIDATE_URL);

Validates value as URL (according to » http://www.faqs.org/rfcs/rfc2396), optionally with required components. Beware a valid URL may not specify the HTTP protocol http:// so further validation may be required to determine the URL uses an expected protocol, e.g. ssh:// or mailto:. Note that the function will only find ASCII URLs to be valid; internationalized domain names (containing non-ASCII characters) will fail.

Example:

if (filter_var($url, FILTER_VALIDATE_URL) === FALSE) {
    die('Not a valid URL');
}

Can't Autowire @Repository annotated interface in Spring Boot

Here is the mistake: as someone said before, you are using org.pharmacy insted of com.pharmacy in componentscan

    package **com**.pharmacy.config;

    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.ComponentScan;


    @SpringBootApplication
    @ComponentScan("**org**.pharmacy")
    public class SpringBootRunner {

SQL Server Text type vs. varchar data type

In SQL server 2005 new datatypes were introduced: varchar(max) and nvarchar(max) They have the advantages of the old text type: they can contain op to 2GB of data, but they also have most of the advantages of varchar and nvarchar. Among these advantages are the ability to use string manipulation functions such as substring().

Also, varchar(max) is stored in the table's (disk/memory) space while the size is below 8Kb. Only when you place more data in the field, it's is stored out of the table's space. Data stored in the table's space is (usually) retrieved quicker.

In short, never use Text, as there is a better alternative: (n)varchar(max). And only use varchar(max) when a regular varchar is not big enough, ie if you expect teh string that you're going to store will exceed 8000 characters.

As was noted, you can use SUBSTRING on the TEXT datatype,but only as long the TEXT fields contains less than 8000 characters.

Nested routes with react router v4 / v5

React Router v6

allows to use both nested routes (like in v3) and separate, splitted routes (v4, v5).

Nested Routes

Keep all routes in one place for small/medium size apps:

<Routes>
  <Route path="/" element={<Home />} >
    <Route path="user" element={<User />} /> 
    <Route path="dash" element={<Dashboard />} /> 
  </Route>
</Routes>

_x000D_

const App = () => {
  return (
    <BrowserRouter>
      <Routes>
        // /js is start path of stack snippet
        <Route path="/js" element={<Home />} >
          <Route path="user" element={<User />} />
          <Route path="dash" element={<Dashboard />} />
        </Route>
      </Routes>
    </BrowserRouter>
  );
}

const Home = () => {
  const location = useLocation()
  return (
    <div>
      <p>URL path: {location.pathname}</p>
      <Outlet />
      <p>
        <Link to="user" style={{paddingRight: "10px"}}>user</Link>
        <Link to="dash">dashboard</Link>
      </p>
    </div>
  )
}

const User = () => <div>User profile</div>
const Dashboard = () => <div>Dashboard</div>

ReactDOM.render(<App />, document.getElementById("root"));

_x000D_

<div id="root"></div>
    <script src="https://unpkg.com/[email protected]/umd/react.production.min.js"></script>
    <script src="https://unpkg.com/[email protected]/umd/react-dom.production.min.js"></script>
    <script src="https://unpkg.com/[email protected]/umd/history.production.min.js"></script>
    <script src="https://unpkg.com/[email protected]/umd/react-router.production.min.js"></script>
    <script src="https://unpkg.com/[email protected]/umd/react-router-dom.production.min.js"></script>
    <script>var { BrowserRouter, Routes, Route, Link, Outlet, useNavigate, useLocation } = window.ReactRouterDOM;</script>

_x000D_

Alternative: Define your routes as plain JavaScript objects via useRoutes.

Separate Routes

You can use separates routes to meet requirements of larger apps like code splitting:

// inside App.jsx:
<Routes>
  <Route path="/*" element={<Home />} />
</Routes>

// inside Home.jsx:
<Routes>
  <Route path="user" element={<User />} />
  <Route path="dash" element={<Dashboard />} />
</Routes>

_x000D_

const App = () => {
  return (
    <BrowserRouter>
      <Routes>
        // /js is start path of stack snippet
        <Route path="/js/*" element={<Home />} />
      </Routes>
    </BrowserRouter>
  );
}

const Home = () => {
  const location = useLocation()
  return (
    <div>
      <p>URL path: {location.pathname}</p>
      <Routes>
        <Route path="user" element={<User />} />
        <Route path="dash" element={<Dashboard />} />
      </Routes>
      <p>
        <Link to="user" style={{paddingRight: "5px"}}>user</Link>
        <Link to="dash">dashboard</Link>
      </p>
    </div>
  )
}

const User = () => <div>User profile</div>
const Dashboard = () => <div>Dashboard</div>

ReactDOM.render(<App />, document.getElementById("root"));

_x000D_

<div id="root"></div>
    <script src="https://unpkg.com/[email protected]/umd/react.production.min.js"></script>
    <script src="https://unpkg.com/[email protected]/umd/react-dom.production.min.js"></script>
    <script src="https://unpkg.com/[email protected]/umd/history.production.min.js"></script>
    <script src="https://unpkg.com/[email protected]/umd/react-router.production.min.js"></script>
    <script src="https://unpkg.com/[email protected]/umd/react-router-dom.production.min.js"></script>
    <script>var { BrowserRouter, Routes, Route, Link, Outlet, useNavigate, useLocation } = window.ReactRouterDOM;</script>

_x000D_

Regular Expression to get all characters before "-"

This is something like the regular expression you need:

([^-]*)-

Quick tests in JavaScript:

/([^-]*)-/.exec('text-1')[1] // 'text'

/([^-]*)-/.exec('foo-bar-1')[1] // 'foo'

/([^-]*)-/.exec('-1')[1] // ''

/([^-]*)-/.exec('quux')[1] // explodes

How to cache Google map tiles for offline usage?

update:

I found the terms of use from Google Map:

Section 10.5

No caching or storage. You will not pre-fetch, cache, index, or store any Content to be used outside the Service, except that you may store limited amounts of Content solely for the purpose of improving the performance of your Maps API Implementation due to network latency (and not for the purpose of preventing Google from accurately tracking usage), and only if such storage: is temporary (and in no event more than 30 calendar days); is secure; does not manipulate or aggregate any part of the Content or Service; and does not modify attribution in any way.

It means we can cache for limited time actually

How to detect input type=file "change" for the same file?

I got this to work by clearing the file input value onClick and then posting the file onChange. This allows the user to select the same file twice in a row and still have the change event fire to post to the server. My example uses the the jQuery form plugin.

$('input[type=file]').click(function(){
    $(this).attr("value", "");
})  
$('input[type=file]').change(function(){
    $('#my-form').ajaxSubmit(options);      
})

Excel VBA Copy a Range into a New Workbook

Modify to suit your specifics, or make more generic as needed:

Private Sub CopyItOver()
  Set NewBook = Workbooks.Add
  Workbooks("Whatever.xlsx").Worksheets("output").Range("A1:K10").Copy
  NewBook.Worksheets("Sheet1").Range("A1").PasteSpecial (xlPasteValues)
  NewBook.SaveAs FileName:=NewBook.Worksheets("Sheet1").Range("E3").Value
End Sub

Creating an empty bitmap and drawing though canvas in Android

This is probably simpler than you're thinking:

int w = WIDTH_PX, h = HEIGHT_PX;

Bitmap.Config conf = Bitmap.Config.ARGB_8888; // see other conf types
Bitmap bmp = Bitmap.createBitmap(w, h, conf); // this creates a MUTABLE bitmap
Canvas canvas = new Canvas(bmp);

// ready to draw on that bitmap through that canvas

Here's a series of tutorials I've found on the topic: Drawing with Canvas Series

dyld: Library not loaded: /usr/local/opt/openssl/lib/libssl.1.0.0.dylib

brew switch openssl 1.0.2t

catalina this is ok.

Search File And Find Exact Match And Print Line?

It's very easy:

numb = raw_input('Input Line: ')
fiIn = open('file.txt').readlines()
for lines in fiIn:
   if numb == lines[0]:
      print lines

How to dump a dict to a json file?

Combine the answer of @mgilson and @gnibbler, I found what I need was this:


d = {"name":"interpolator",
     "children":[{'name':key,"size":value} for key,value in sample.items()]}
j = json.dumps(d, indent=4)
f = open('sample.json', 'w')
print >> f, j
f.close()

It this way, I got a pretty-print json file. The tricks print >> f, j is found from here: http://www.anthonydebarros.com/2012/03/11/generate-json-from-sql-using-python/

What is the best IDE for PHP?

Eclipse with PDT.

Android Preventing Double Click On A Button

you can also use rx bindings by jake wharton to accomplish this. here is a sample that pads 2 seconds between successive clicks:

RxView.clicks(btnSave)
                .throttleFirst(2000, TimeUnit.MILLISECONDS, AndroidSchedulers.mainThread())
                .subscribe(new Consumer<Object>() {
                    @Override
                    public void accept( Object v) throws Exception {
//handle onclick event here
                });

//note: ignore the Object v in this case and i think always.

jQuery find events handlers registered with an object

I combined some of the answers above and created this crazy looking but functional script that lists hopefully most of the event listeners on the given element. Feel free to optimize it here.

_x000D_

var element = $("#some-element");_x000D_
_x000D_
// sample event handlers_x000D_
element.on("mouseover", function () {_x000D_
  alert("foo");_x000D_
});_x000D_
_x000D_
$(".parent-element").on("mousedown", "span", function () {_x000D_
  alert("bar");_x000D_
});_x000D_
_x000D_
$(document).on("click", "span", function () {_x000D_
  alert("xyz");_x000D_
});_x000D_
_x000D_
var collection = element.parents()_x000D_
  .add(element)_x000D_
  .add($(document));_x000D_
collection.each(function() {_x000D_
  var currentEl = $(this) ? $(this) : $(document);_x000D_
  var tagName = $(this)[0].tagName ? $(this)[0].tagName : "DOCUMENT";_x000D_
  var events = $._data($(this)[0], "events");_x000D_
  var isItself = $(this)[0] === element[0]_x000D_
  if (!events) return;_x000D_
  $.each(events, function(i, event) {_x000D_
    if (!event) return;_x000D_
    $.each(event, function(j, h) {_x000D_
      var found = false;        _x000D_
      if (h.selector && h.selector.length > 0) {_x000D_
        currentEl.find(h.selector).each(function () {_x000D_
          if ($(this)[0] === element[0]) {_x000D_
            found = true;_x000D_
          }_x000D_
        });_x000D_
      } else if (!h.selector && isItself) {_x000D_
        found = true;_x000D_
      }_x000D_
_x000D_
      if (found) {_x000D_
        console.log("################ " + tagName);_x000D_
        console.log("event: " + i);_x000D_
        console.log("selector: '" + h.selector + "'");_x000D_
        console.log(h.handler);_x000D_
      }_x000D_
    });_x000D_
  });_x000D_
});

_x000D_

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>_x000D_
_x000D_
<div class="parent-element">_x000D_
  <span id="some-element"></span>_x000D_
</div>

_x000D_

Removing duplicates from a String in Java

This is improvement on solution suggested by @Dave. Here, I am implementing in single loop only.

Let's reuse the return of set.add(T item) method and add it simultaneously in StringBuffer if add is successfull

This is just O(n). No need to make a loop again.

String string = "aabbccdefatafaz";

char[] chars = string.toCharArray();
StringBuilder sb = new StringBuilder();
Set<Character> charSet = new LinkedHashSet<Character>();
for (char c : chars) {
    if(charSet.add(c) ){
        sb.append(c);
    }

}
System.out.println(sb.toString()); // abcdeftz

How to copy from CSV file to PostgreSQL table with headers in CSV file?

You can use d6tstack which creates the table for you and is faster than pd.to_sql() because it uses native DB import commands. It supports Postgres as well as MYSQL and MS SQL.

import pandas as pd
df = pd.read_csv('table.csv')
uri_psql = 'postgresql+psycopg2://usr:pwd@localhost/db'
d6tstack.utils.pd_to_psql(df, uri_psql, 'table')

It is also useful for importing multiple CSVs, solving data schema changes and/or preprocess with pandas (eg for dates) before writing to db, see further down in examples notebook

d6tstack.combine_csv.CombinerCSV(glob.glob('*.csv'), 
    apply_after_read=apply_fun).to_psql_combine(uri_psql, 'table')

Run a shell script with an html button

This is really just an expansion of BBB's answer which lead to to get my experiment working.

This script will simply create a file /tmp/testfile when you click on the button that says "Open Script".

This requires 3 files.

The actual HTML Website with a button.
A php script which executes the script
A Script

The File Tree:

root@test:/var/www/html# tree testscript/
testscript/
+-- index.html
+-- testexec.php
+-- test.sh

1. The main WebPage:

root@test:/var/www/html# cat testscript/index.html
<form action="/testscript/testexec.php">
    <input type="submit" value="Open Script">
</form>

2. The PHP Page that runs the script and redirects back to the main page:

root@test:/var/www/html# cat testscript/testexec.php
<?php
shell_exec("/var/www/html/testscript/test.sh");
header('Location: http://192.168.1.222/testscript/index.html?success=true');
?>

3. The Script :

root@test:/var/www/html# cat testscript/test.sh

#!/bin/bash

touch /tmp/testfile

jQuery/JavaScript to replace broken images

$(window).bind('load', function() {
  $('img').each(function() {
    if( (typeof this.naturalWidth != "undefined" && this.naturalWidth == 0) 
    ||  this.readyState == 'uninitialized'                                  ) {
        $(this).attr('src', 'missing.jpg');
    }
  });
});

Source: http://www.developria.com/2009/03/jquery-quickie---broken-images.html

Save array in mysql database

You can store the array using serialize/unserialize. With that solution they cannot easily be used from other programming languages, so you may consider using json_encode/json_decode instead (which gives you a widely supported format). Avoid using implode/explode for this since you'll probably end up with bugs or security flaws.

Note that this makes your table non-normalized, which may be a bad idea since you cannot easily query the data. Therefore consider this carefully before going forward. May you need to query the data for statistics or otherwise? Are there other reasons to normalize the data?

Also, don't save the raw $_POST array. Someone can easily make their own web form and post data to your site, thereby sending a really large form which takes up lots of space. Save those fields you want and make sure to validate the data before saving it (so you won't get invalid values).

Get values from an object in JavaScript

I am sorry that your concluding question is not that clear but you are wrong from the very first line. The variable data is an Object not an Array

To access the attributes of an object is pretty easy:

alert(data.second);

But, if this does not completely answer your question, please clarify it and post back.

Thanks !

How do I remove the passphrase for the SSH key without having to create a new key?

Short answer:

$ ssh-keygen -p

This will then prompt you to enter the keyfile location, the old passphrase, and the new passphrase (which can be left blank to have no passphrase).

If you would like to do it all on one line without prompts do:

$ ssh-keygen -p [-P old_passphrase] [-N new_passphrase] [-f keyfile]

Important: Beware that when executing commands they will typically be logged in your ~/.bash_history file (or similar) in plain text including all arguments provided (i.e. the passphrases in this case). It is, therefore, is recommended that you use the first option unless you have a specific reason to do otherwise.

Notice though that you can still use -f keyfile without having to specify -P nor -N, and that the keyfile defaults to ~/.ssh/id_rsa, so in many cases, it's not even needed.

You might want to consider using ssh-agent, which can cache the passphrase for a time. The latest versions of gpg-agent also support the protocol that is used by ssh-agent.

How can I generate a tsconfig.json file?

You need to have typescript library installed and then you can use

npx tsc --init

If the response is error TS5023: Unknown compiler option 'init'. that means the library is not installed

yarn add --dev typescript

and run npx command again

How can I use console logging in Internet Explorer?

In his book, "Secrets of Javascript Ninja", John Resig (creator of jQuery) has a really simple code which will handle cross-browser console.log issues. He explains that he would like to have a log message which works with all browsers and here is how he coded it:

function log() {
  try {
    console.log.apply(console, arguments);
  } catch(e) {
  try {
    opera.postError.apply(opera, arguments);
  }
  catch(e) {
    alert(Array.prototype.join.call( arguments, " "));
  }
}

What is the difference between ( for... in ) and ( for... of ) statements?

When I first started out learning the for in and of loop, I was confused with my output too, but with a couple of research and understanding you can think of the individual loop like the following : The

for...in loop returns the indexes of the individual property and has no effect of impact on the property's value, it loops and returns information on the property and not the value. E.g

let profile = { name : "Naphtali", age : 24, favCar : "Mustang", favDrink : "Baileys" }

The above code is just creating an object called profile, we'll use it for both our examples, so, don't be confused when you see the profile object on an example, just know it was created.

So now let us use the for...in loop below

for(let myIndex in profile){
    console.log(`The index of my object property is ${myIndex}`)
}
 // Outputs : 
        The index of my object property is 0
        The index of my object property is 1
        The index of my object property is 2
        The index of my object property is 3

Now Reason for the output being that we have Four(4) properties in our profile object and indexing as we all know starts from 0...n, so, we get the index of properties 0,1,2,3 since we are working with the for..in loop.

for...of loop* can return either the property, value or both, Let's take a look at how. In javaScript, we can't loop through objects normally as we would on arrays, so, there are a few elements we can use to access either of our choices from an object.
- Object.keys(object-name-goes-here) >>> Returns the keys or properties of an object.
- Object.values(object-name-goes-here) >>> Returns the values of an object.
- Object.entries(object-name-goes-here) >>> Returns both the keys and values of an object.

Below are examples of their usage, pay attention to Object.entries() :

Step One: Convert the object to get either its key, value, or both.
Step Two: loop through.


// Getting the keys/property

   Step One: let myKeys = ***Object.keys(profile)***
   Step Two: for(let keys of myKeys){
             console.log(`The key of my object property is ${keys}`)
           }

// Getting the values of the property

    Step One: let myValues = ***Object.values(profile)***
    Step Two : for(let values of myValues){
                 console.log(`The value of my object property is ${values}`)
               }

When using Object.entries() have it that you are calling two entries on the object, i.e the keys and values. You can call both by either of the entry. Example Below.

Step One: Convert the object to entries, using ***Object.entries(object-name)***
Step Two: **Destructure** the ***entries object which carries the keys and values*** 
like so **[keys, values]**, by so doing, you have access to either or both content.


    // Getting the keys/property

       Step One: let myKeysEntry = ***Object.entries(profile)***
       Step Two: for(let [keys, values] of myKeysEntry){
                 console.log(`The key of my object property is ${keys}`)
               }

    // Getting the values of the property

        Step One: let myValuesEntry = ***Object.entries(profile)***
        Step Two : for(let [keys, values] of myValuesEntry){
                     console.log(`The value of my object property is ${values}`)
                   }

    // Getting both keys and values

        Step One: let myBothEntry = ***Object.entries(profile)***
        Step Two : for(let [keys, values] of myBothEntry){
                     console.log(`The keys of my object is ${keys} and its value 
is ${values}`)
                   }

Make comments on unclear parts section(s).

Plotting time-series with Date labels on x-axis

I like using the ggplot2 for this sort of thing:

df$Date <- as.Date( df$Date, '%m/%d/%Y')
require(ggplot2)
ggplot( data = df, aes( Date, Visits )) + geom_line()

enter image description here

Node.js vs .Net performance

How do I apply a diff patch on Windows?

I made pure Python tool just for that. It has predictable cross-platform behavior. Although it doesn't create new files (at the time of writing this) and lacks a GUI, it can be used as a library to create graphic tool.

UPDATE: It should be more convenient to use it if you have Python installed.

pip install patch
python -m patch

is the + operator less performant than StringBuffer.append()

Try this:

var s = ["<a href='", url, "'>click here</a>"].join("");

How should I read a file line-by-line in Python?

f = open('test.txt','r')
for line in f.xreadlines():
    print line
f.close()

Looping over a list in Python

Do this instead:

values = [[1,2,3],[4,5]]
for x in values:
    if len(x) == 3:
       print(x)

How to download Google Play Services in an Android emulator?

If your emulator x86 this method works your me.

Download and install http://opengapps.org/app/opengapps-app-v16.apk. And select nano pack

More info http://opengapps.org/app/

How do you discover model attributes in Rails?

There is a rails plugin called Annotate models, that will generate your model attributes on the top of your model files here is the link:

https://github.com/ctran/annotate_models

to keep the annotation in sync, you can write a task to re-generate annotate models after each deploy.

Threads vs Processes in Linux

I'd have to agree with what you've been hearing. When we benchmark our cluster (xhpl and such), we always get significantly better performance with processes over threads. </anecdote>

How can I change all input values to uppercase using Jquery?

$('#id-submit').click(function () {
    $("input").val(function(i,val) {
        return val.toUpperCase();
    });
});

FIDDLE

Place API key in Headers or URL

It is better to use API Key in header, not in URL.

URLs are saved in browser's history if it is tried from browser. It is very rare scenario. But problem comes when the backend server logs all URLs. It might expose the API key.

In two ways, you can use API Key in header

Basic Authorization:

Example from stripe:

curl https://api.stripe.com/v1/charges -u sk_test_BQokikJOvBiI2HlWgH4olfQ2:

curl uses the -u flag to pass basic auth credentials (adding a colon after your API key will prevent it from asking you for a password).

Custom Header

curl -H "X-API-KEY: 6fa741de1bdd1d91830ba" https://api.mydomain.com/v1/users

ToString() function in Go

Attach a String() string method to any named type and enjoy any custom "ToString" functionality:

package main

import "fmt"

type bin int

func (b bin) String() string {
        return fmt.Sprintf("%b", b)
}

func main() {
        fmt.Println(bin(42))
}

Playground: http://play.golang.org/p/Azql7_pDAA

Output

Learning Ruby on Rails

I came from a Java background to Ruby to. I found this tutorial helpful http://www.ruby-lang.org/en/documentation/ruby-from-other-languages/to-ruby-from-java/. When it comes to learning rails I cannot say how much I use script\console. It allows you to play with the code and learn how to do things that you are not sure about.

The only book I ever bought was Agile Web Development with Rails, Third Edition http://www.pragprog.com/titles/rails3/agile-web-development-with-rails-third-edition. It was quite useful and provided a good overview of the Rails framework. In addition to that I regular watch Railscasts(http://railscasts.com), which is a great screen casting blog that covers all kinds of Rails topics.

I personally prefer using Linux (because git works better). But, I have also used windows and besides git I do not think the OS choice will impact your programming.

I use netbeans for my IDE and occasionally vim (with the rails plugin). I like netbeans but, I find that it can still be a little flaky when it comes to the Rails support (not all the features work all the time).

How do I set a fixed background image for a PHP file?

It's not a good coding to put PHP code into CSS

body
{
    background-image:url('bg.png');
}

that's it

ETag vs Header Expires

Another summary:

You need to use both. ETags are a "server side" information. Expires are a "Client side" caching.

Use ETags except if you have a load-balanced server. They are safe and will let clients know they should get new versions of your server files every time you change something on your side.
Expires must be used with caution, as if you set a expiration date far in the future but want to change one of the files immediatelly (a JS file for instance), some users may not get the modified version until a long time!

prevent refresh of page when button inside form clicked

The problem is that it triggers the form submission. If you make the getData function return false then it should stop the form from submitting.

Alternatively, you could also use the preventDefault method of the event object:

function getData(e) {
    e.preventDefault();
}

Check if String / Record exists in DataTable

Something like this

 string find = "item_manuf_id = 'some value'";
 DataRow[] foundRows = table.Select(find);

How to iterate through table in Lua?

If you want to refer to a nested table by multiple keys you can just assign them to separate keys. The tables are not duplicated, and still reference the same values.

arr = {}
apples = {'a', "red", 5 }
arr.apples = apples
arr[1] = apples

This code block lets you iterate through all the key-value pairs in a table (http://lua-users.org/wiki/TablesTutorial):

for k,v in pairs(t) do
 print(k,v)
end

How can I inspect the file system of a failed `docker build`?

Everytime docker successfully executes a RUN command from a Dockerfile, a new layer in the image filesystem is committed. Conveniently you can use those layers ids as images to start a new container.

Take the following Dockerfile:

FROM busybox
RUN echo 'foo' > /tmp/foo.txt
RUN echo 'bar' >> /tmp/foo.txt

and build it:

$ docker build -t so-2622957 .
Sending build context to Docker daemon 47.62 kB
Step 1/3 : FROM busybox
 ---> 00f017a8c2a6
Step 2/3 : RUN echo 'foo' > /tmp/foo.txt
 ---> Running in 4dbd01ebf27f
 ---> 044e1532c690
Removing intermediate container 4dbd01ebf27f
Step 3/3 : RUN echo 'bar' >> /tmp/foo.txt
 ---> Running in 74d81cb9d2b1
 ---> 5bd8172529c1
Removing intermediate container 74d81cb9d2b1
Successfully built 5bd8172529c1

You can now start a new container from 00f017a8c2a6, 044e1532c690 and 5bd8172529c1:

$ docker run --rm 00f017a8c2a6 cat /tmp/foo.txt
cat: /tmp/foo.txt: No such file or directory

$ docker run --rm 044e1532c690 cat /tmp/foo.txt
foo

$ docker run --rm 5bd8172529c1 cat /tmp/foo.txt
foo
bar

of course you might want to start a shell to explore the filesystem and try out commands:

$ docker run --rm -it 044e1532c690 sh      
/ # ls -l /tmp
total 4
-rw-r--r--    1 root     root             4 Mar  9 19:09 foo.txt
/ # cat /tmp/foo.txt 
foo

When one of the Dockerfile command fails, what you need to do is to look for the id of the preceding layer and run a shell in a container created from that id:

docker run --rm -it <id_last_working_layer> bash -il

Once in the container:

try the command that failed, and reproduce the issue
then fix the command and test it
finally update your Dockerfile with the fixed command

If you really need to experiment in the actual layer that failed instead of working from the last working layer, see Drew's answer.

ASP.NET MVC Bundle not rendering script files on staging server. It works on development server

By adding following code of line in bundle to config it works for me

bundles.IgnoreList.Clear();

Follow the link for more explanation

Can I use VARCHAR as the PRIMARY KEY?

A blanket "no you shouldn't" is terrible advice. This is perfectly reasonable in many situations depending on your use case, workload, data entropy, hardware, etc.. What you shouldn't do is make assumptions.

It should be noted that you can specify a prefix which will limit MySQL's indexing, thereby giving you some help in narrowing down the results before scanning the rest. This may, however, become less useful over time as your prefix "fills up" and becomes less unique.

It's very simple to do, e.g.:

CREATE TABLE IF NOT EXISTS `foo` (
  `id` varchar(128),
  PRIMARY KEY (`id`(4))
)

Also note that the prefix (4) appears after the column quotes. Where the 4 means that it should use the first 4 characters of the 128 possible characters that can exist as the id.

Lastly, you should read how index prefixes work and their limitations before using them: https://dev.mysql.com/doc/refman/8.0/en/create-index.html

How to loop over grouped Pandas dataframe?

df.groupby('l_customer_id_i').agg(lambda x: ','.join(x)) does already return a dataframe, so you cannot loop over the groups anymore.

In general:

df.groupby(...) returns a GroupBy object (a DataFrameGroupBy or SeriesGroupBy), and with this, you can iterate through the groups (as explained in the docs here). You can do something like:
```
grouped = df.groupby('A')

for name, group in grouped:
    ...
```
When you apply a function on the groupby, in your example df.groupby(...).agg(...) (but this can also be transform, apply, mean, ...), you combine the result of applying the function to the different groups together in one dataframe (the apply and combine step of the 'split-apply-combine' paradigm of groupby). So the result of this will always be again a DataFrame (or a Series depending on the applied function).

How to remove folders with a certain name

I ended up here looking to delete my node_modules folders before doing a backup of my work in progress using rsync. A key requirements is that the node_modules folder can be nested, so you need the -prune option.

First I ran this to visually verify the folders to be deleted:

find -type d -name node_modules -prune

Then I ran this to delete them all:

find -type d -name node_modules -prune -exec rm -rf {} \;

Thanks to pistache

How do I pass an object from one activity to another on Android?

This answer is specific to situations where the objects to be passed has nested class structure. With nested class structure, making it Parcelable or Serializeable is a bit tedious. And, the process of serialising an object is not efficient on Android. Consider the example below,

class Myclass    {
  int a;
  class SubClass    {
       int b;
  }
}

With Google's GSON library, you can directly parse an object into a JSON formatted String and convert it back to the object format after usage. For example,

MyClass src = new MyClass();
Gson gS = new Gson();
String target = gS.toJson(src); // Converts the object to a JSON String

Now you can pass this String across activities as a StringExtra with the activity intent.

Intent i = new Intent(FromActivity.this, ToActivity.class);
i.putExtra("MyObjectAsString", target);

Then in the receiving activity, create the original object from the string representation.

String target = getIntent().getStringExtra("MyObjectAsString");
MyClass src = gS.fromJson(target, MyClass.class); // Converts the JSON String to an Object

It keeps the original classes clean and reusable. Above of all, if these class objects are created from the web as JSON objects, then this solution is very efficient and time saving.

UPDATE

While the above explained method works for most situations, for obvious performance reasons, do not rely on Android's bundled-extra system to pass objects around. There are a number of solutions makes this process flexible and efficient, here are a few. Each has its own pros and cons.

Javascript/DOM: How to remove all events of a DOM object?

var div = getElementsByTagName('div')[0]; /* first div found; you can use getElementById for more specific element */
div.onclick = null; // OR:
div.onclick = function(){};

//edit

I didn't knew what method are you using for attaching events. For addEventListener you can use this:

div.removeEventListener('click',functionName,false); // functionName is the name of your callback function

more details

lambda expression join multiple tables with select and where clause

If I understand your questions correctly, all you need to do is add the .Where(m => m.r.u.UserId == 1):

    var UserInRole = db.UserProfiles.
        Join(db.UsersInRoles, u => u.UserId, uir => uir.UserId,
        (u, uir) => new { u, uir }).
        Join(db.Roles, r => r.uir.RoleId, ro => ro.RoleId, (r, ro) => new { r, ro })
        .Where(m => m.r.u.UserId == 1)
        .Select (m => new AddUserToRole
        {
            UserName = m.r.u.UserName,
            RoleName = m.ro.RoleName
        });

Hope that helps.

Why is quicksort better than mergesort?

While they're both in the same complexity class, that doesn't mean they both have the same runtime. Quicksort is usually faster than mergesort, just because it's easier to code a tight implementation and the operations it does can go faster. It's because that quicksort is generally faster that people use it instead of mergesort.

However! I personally often will use mergesort or a quicksort variant that degrades to mergesort when quicksort does poorly. Remember. Quicksort is only O(n log n) on average. It's worst case is O(n^2)! Mergesort is always O(n log n). In cases where realtime performance or responsiveness is a must and your input data could be coming from a malicious source, you should not use plain quicksort.

What does the error "JSX element type '...' does not have any construct or call signatures" mean?

In my case I was missing new inside the type definition.

some-js-component.d.ts file:

import * as React from "react";

export default class SomeJSXComponent extends React.Component<any, any> {
    new (props: any, context?: any)
}

and inside the tsx file where I was trying to import the untyped component:

import SomeJSXComponent from 'some-js-component'

const NewComp = ({ asdf }: NewProps) => <SomeJSXComponent withProps={asdf} />

How to cast List<Object> to List<MyClass>

Your best bet is to create a new List<Customer>, iterate through the List<Object>, add each item to the new list, and return that.

Determine if two rectangles overlap each other?

bool Square::IsOverlappig(Square &other)
{
    bool result1 = other.x >= x && other.y >= y && other.x <= (x + width) && other.y <= (y + height); // other's top left falls within this area
    bool result2 = other.x >= x && other.y <= y && other.x <= (x + width) && (other.y + other.height) <= (y + height); // other's bottom left falls within this area
    bool result3 = other.x <= x && other.y >= y && (other.x + other.width) <= (x + width) && other.y <= (y + height); // other's top right falls within this area
    bool result4 = other.x <= x && other.y <= y && (other.x + other.width) >= x && (other.y + other.height) >= y; // other's bottom right falls within this area
    return result1 | result2 | result3 | result4;
}

How to make overlay control above all other controls?

This is a common function of Adorners in WPF. Adorners typically appear above all other controls, but the other answers that mention z-order may fit your case better.

TS1086: An accessor cannot be declared in ambient context

Setting "skipLibCheck": true in tsconfig.json solved my problem

"compilerOptions": {
    "skipLibCheck": true
}

Oracle SQL : timestamps in where clause

For everyone coming to this thread with fractional seconds in your timestamp use:

to_timestamp('2018-11-03 12:35:20.419000', 'YYYY-MM-DD HH24:MI:SS.FF')

What is the difference between const int, const int const, and int const *?

Constant reference:

A reference to a variable (here int), which is constant. We pass the variable as a reference mainly, because references are smaller in size than the actual value, but there is a side effect and that is because it is like an alias to the actual variable. We may accidentally change the main variable through our full access to the alias, so we make it constant to prevent this side effect.
```
int var0 = 0;
const int &ptr1 = var0;
ptr1 = 8; // Error
var0 = 6; // OK
```
Constant pointers

Once a constant pointer points to a variable then it cannot point to any other variable.
```
int var1 = 1;
int var2 = 0;

int *const ptr2 = &var1;
ptr2 = &var2; // Error
```
Pointer to constant

A pointer through which one cannot change the value of a variable it points is known as a pointer to constant.
```
int const * ptr3 = &var2;
*ptr3 = 4; // Error
```
Constant pointer to a constant

A constant pointer to a constant is a pointer that can neither change the address it's pointing to and nor can it change the value kept at that address.
```
int var3 = 0;
int var4 = 0;
const int * const ptr4 = &var3;
*ptr4 = 1;     // Error
 ptr4 = &var4; // Error
```

Android Call an method from another class

And, if you don't want to instantiate Class2, declare UpdateEmployee as static and call it like this:

Class2.UpdateEmployee();

However, you'll normally want to do what @parag said.

Maintain model of scope when changing between views in AngularJS

Angular doesn't really provide what you are looking for out of the box. What i would do to accomplish what you're after is use the following add ons

UI Router & UI Router Extras

These two will provide you with state based routing and sticky states, you can tab between states and all information will be saved as the scope "stays alive" so to speak.

Check the documentation on both as it's pretty straight forward, ui router extras also has a good demonstration of how sticky states works.

Post form data using HttpWebRequest

Use this code:

internal void SomeFunction() {
    Dictionary<string, string> formField = new Dictionary<string, string>();
    
    formField.Add("Name", "Henry");
    formField.Add("Age", "21");
    
    string body = GetBodyStringFromDictionary(formField);
    // output : Name=Henry&Age=21
}

internal string GetBodyStringFromDictionary(Dictionary<string, string> formField)
{
    string body = string.Empty;
    foreach (var pair in formField)
    {
        body += $"{pair.Key}={pair.Value}&";   
    }

    // delete last "&"
    body = body.Substring(0, body.Length - 1);

    return body;
}

Using LINQ to concatenate strings

You can use StringBuilder in Aggregate:

  List<string> strings = new List<string>() { "one", "two", "three" };

  StringBuilder sb = strings
    .Select(s => s)
    .Aggregate(new StringBuilder(), (ag, n) => ag.Append(n).Append(", "));

  if (sb.Length > 0) { sb.Remove(sb.Length - 2, 2); }

  Console.WriteLine(sb.ToString());

(The Select is in there just to show you can do more LINQ stuff.)

Sticky and NON-Sticky sessions

When your website is served by only one web server, for each client-server pair, a session object is created and remains in the memory of the web server. All the requests from the client go to this web server and update this session object. If some data needs to be stored in the session object over the period of interaction, it is stored in this session object and stays there as long as the session exists.

However, if your website is served by multiple web servers which sit behind a load balancer, the load balancer decides which actual (physical) web-server should each request go to. For example, if there are 3 web servers A, B and C behind the load balancer, it is possible that www.mywebsite.com/index.jsp is served from server A, www.mywebsite.com/login.jsp is served from server B and www.mywebsite.com/accoutdetails.php are served from server C.

Now, if the requests are being served from (physically) 3 different servers, each server has created a session object for you and because these session objects sit on three independent boxes, there's no direct way of one knowing what is there in the session object of the other. In order to synchronize between these server sessions, you may have to write/read the session data into a layer which is common to all - like a DB. Now writing and reading data to/from a db for this use-case may not be a good idea. Now, here comes the role of sticky-session.

If the load balancer is instructed to use sticky sessions, all of your interactions will happen with the same physical server, even though other servers are present. Thus, your session object will be the same throughout your entire interaction with this website.

To summarize, In case of Sticky Sessions, all your requests will be directed to the same physical web server while in case of a non-sticky loadbalancer may choose any webserver to serve your requests.

As an example, you may read about Amazon's Elastic Load Balancer and sticky sessions here : http://aws.typepad.com/aws/2010/04/new-elastic-load-balancing-feature-sticky-sessions.html

HTML button to NOT submit form

return false; at the end of the onclick handler will do the job. However, it's be better to simply add type="button" to the <button> - that way it behaves properly even without any JavaScript.

Converting list to numpy array

If you have a list of lists, you only needed to use ...

import numpy as np
...
npa = np.asarray(someListOfLists, dtype=np.float32)

per this LINK in the scipy / numpy documentation. You just needed to define dtype inside the call to asarray.

Port 80 is being used by SYSTEM (PID 4), what is that?

This wouldn't explain the PID side of things, but if you run Skype, it likes to use Port 80 for some reason.

C#: Assign same value to multiple variables in single statement

Your example would be:

int num1 = 1;
int num2 = 1;

num1 = num2 = 5;

Convert array of JSON object strings to array of JS objects

If you really have:

var s = ['{"Select":"11", "PhotoCount":"12"}','{"Select":"21", "PhotoCount":"22"}'];

then simply:

var objs = $.map(s, $.parseJSON);

Here's a demo.

Error: org.testng.TestNGException: Cannot find class in classpath: EmpClass

This issue can be resolved by adding TestNG.class package to OnlineStore package as below

Step 1: Build Path > Configure Build Path > Java Build Path > Select "Project" tab
Step 2: Click "add" button and select the project with contains the TestNG source.
Step 3 select TestNG.xml run as "TestNG Suite"

Android: upgrading DB version and adding new table

Your code looks correct. My suggestion is that the database already thinks it's upgraded. If you executed the project after incrementing the version number, but before adding the execSQL call, the database on your test device/emulator may already believe it's at version 2.

A quick way to verify this would be to change the version number to 3 -- if it upgrades after that, you know it was just because your device believed it was already upgraded.

How to run multiple SQL commands in a single SQL connection?

Here you can find Postgre example, this code run multiple sql commands (update 2 columns) within single SQL connection

public static class SQLTest
    {
        public static void NpgsqlCommand()
        {
            using (NpgsqlConnection connection = new NpgsqlConnection("Server = ; Port = ; User Id = ; " + "Password = ; Database = ;"))
            {
                NpgsqlCommand command1 = new NpgsqlCommand("update xy set xw = 'a' WHERE aa='bb'", connection);
                NpgsqlCommand command2 = new NpgsqlCommand("update xy set xw = 'b' where bb = 'cc'", connection);
                command1.Connection.Open();
                command1.ExecuteNonQuery();
                command2.ExecuteNonQuery();
                command2.Connection.Close();
            }
        }
    }

How to use JavaScript to change div backgroundColor

<script type="text/javascript">
 function enter(elem){
     elem.style.backgroundColor = '#FF0000';
 }

 function leave(elem){
     elem.style.backgroundColor = '#FFFFFF';
 }
</script>
 <div onmouseover="enter(this)" onmouseout="leave(this)">
       Some Text
 </div>

Safe Area of Xcode 9

I want to mention something that caught me first when I was trying to adapt a SpriteKit-based app to avoid the round edges and "notch" of the new iPhone X, as suggested by the latest Human Interface Guidelines: The new property safeAreaLayoutGuide of UIView needs to be queried after the view has been added to the hierarchy (for example, on -viewDidAppear:) in order to report a meaningful layout frame (otherwise, it just returns the full screen size).

From the property's documentation:

The layout guide representing the portion of your view that is unobscured by bars and other content. When the view is visible onscreen, this guide reflects the portion of the view that is not covered by navigation bars, tab bars, toolbars, and other ancestor views. (In tvOS, the safe area reflects the area not covered the screen's bezel.) If the view is not currently installed in a view hierarchy, or is not yet visible onscreen, the layout guide edges are equal to the edges of the view.

(emphasis mine)

If you read it as early as -viewDidLoad:, the layoutFrame of the guide will be {{0, 0}, {375, 812}} instead of the expected {{0, 44}, {375, 734}}

Difference between `Optional.orElse()` and `Optional.orElseGet()`

First of all check the declaration of both the methods.

1) OrElse: Execute logic and pass result as argument.

public T orElse(T other) {    
 return value != null ? value : other;
}

2) OrElseGet: Execute logic if value inside the optional is null

public T orElseGet(Supplier<? extends T> other) {
  return value != null ? value : other.get(); 
}

Some explanation on above declaration: The argument of “Optional.orElse” always gets executed irrespective of the value of the object in optional (null, empty or with value). Always consider the above-mentioned point in mind while using “Optional.orElse”, otherwise use of “Optional.orElse” can be very risky in the following situation.

Risk-1) Logging Issue: If content inside orElse contains any log statement: In this case, you will end up logging it every time.

Optional.of(getModel())
   .map(x -> {
      //some logic
   })
  .orElse(getDefaultAndLogError());

getDefaultAndLogError() {
  log.error("No Data found, Returning default");
  return defaultValue;
}

Risk-2) Performance Issue: If content inside orElse is time-intensive: Time intensive content can be any i/o operations DB call, API call, file reading. If we put such content in orElse(), the system will end up executing a code of no use.

Optional.of(getModel())
   .map(x -> //some logic)
   .orElse(getDefaultFromDb());

getDefaultFromDb() {
   return dataBaseServe.getDefaultValue(); //api call, db call.
}

Risk-3) Illegal State or Bug Issue: If content inside orElse is mutating some object state: We might be using the same object at another place let say inside Optional.map function and it can put us in a critical bug.

List<Model> list = new ArrayList<>();
Optional.of(getModel())
  .map(x -> {
  })
  .orElse(get(list));

get(List < String > list) {
   log.error("No Data found, Returning default");
   list.add(defaultValue);
   return defaultValue;
}

Then, When can we go with orElse()? Prefer using orElse when the default value is some constant object, enum. In all above cases we can go with Optional.orElseGet() (which only executes when Optional contains non empty value)instead of Optional.orElse(). Why?? In orElse, we pass default result value, but in orElseGet we pass Supplier and method of Supplier only executes if the value in Optional is null.

Key takeaways from this:

Do not use “Optional.orElse” if it contains any log statement.
Do not use “Optional.orElse” if it contains time-intensive logic.
Do not use “Optional.orElse” if it is mutating some object state.
Use “Optional.orElse” if we have to return a constant, enum.
Prefer “Optional.orElseGet” in the situations mentioned in 1,2 and 3rd points.

I have explained this in point-2 (“Optional.map/Optional.orElse” != “if/else”) my medium blog. Use Java8 as a programmer not as a coder

How do I set default value of select box in angularjs

  <select ng-model="selectedCar" ><option ng-repeat="car in cars "  value="{{car.model}}">{{car.model}}</option></select>
<script>var app = angular.module('myApp', []);app.controller('myCtrl', function($scope) { $scope.cars = [{model : "Ford Mustang", color : "red"}, {model : "Fiat 500", color : "white"},{model : "Volvo XC90", color : "black"}];
$scope.selectedCar=$scope.cars[0].model ;});

Signed to unsigned conversion in C - is it always safe?

As was previously answered, you can cast back and forth between signed and unsigned without a problem. The border case for signed integers is -1 (0xFFFFFFFF). Try adding and subtracting from that and you'll find that you can cast back and have it be correct.

However, if you are going to be casting back and forth, I would strongly advise naming your variables such that it is clear what type they are, eg:

int iValue, iResult;
unsigned int uValue, uResult;

It is far too easy to get distracted by more important issues and forget which variable is what type if they are named without a hint. You don't want to cast to an unsigned and then use that as an array index.

Error: Could not find or load main class

This solved the issue for me today:

cd /path/to/project
cd build
rm -r classes

Then clean&build it and run the individual files you need.

How can I define an interface for an array of objects with Typescript?

Use like this!

interface Iinput {
  label: string
  placeholder: string
  register: any
  type?: string
  required: boolean
}


// This is how it can be done

const inputs: Array<Iinput> = [
  {
    label: "Title",
    placeholder: "Bought something",
    register: register,
    required: true,
  },
]

Error importing SQL dump into MySQL: Unknown database / Can't create database

It sounds like your database dump includes the information for creating the database. So don't give the MySQL command line a database name. It will create the new database and switch to it to do the import.

Installing packages in Sublime Text 2

Enabling a previously-installed Sublime Text package

If you have a subdirectory under Sublime Text 2\Packages for a package that isn't working, you may need to enable it.

Follow these steps to enable an installed package:

Preferences > Package Control > Enable Package
Select the package you want to enable from the list

Getting list of tables, and fields in each, in a database

Your other inbuilt friend here is the system sproc SP_HELP.

sample usage ::

sp_help <MyTableName>

It returns a lot more info than you will really need, but at least 90% of your possible requirements will be catered for.

How to add a reference programmatically

Ommit

There are two ways to add references via VBA to your projects

1) Using GUID

2) Directly referencing the dll.

Let me cover both.

But first these are 3 things you need to take care of

a) Macros should be enabled

b) In Security settings, ensure that "Trust Access To Visual Basic Project" is checked

enter image description here

c) You have manually set a reference to `Microsoft Visual Basic for Applications Extensibility" object

enter image description here

Way 1 (Using GUID)

I usually avoid this way as I have to search for the GUID in the registry... which I hate LOL. More on GUID here.

Topic: Add a VBA Reference Library via code

Link: http://www.vbaexpress.com/kb/getarticle.php?kb_id=267

'Credits: Ken Puls
Sub AddReference()
     'Macro purpose:  To add a reference to the project using the GUID for the
     'reference library

    Dim strGUID As String, theRef As Variant, i As Long

     'Update the GUID you need below.
    strGUID = "{00020905-0000-0000-C000-000000000046}"

     'Set to continue in case of error
    On Error Resume Next

     'Remove any missing references
    For i = ThisWorkbook.VBProject.References.Count To 1 Step -1
        Set theRef = ThisWorkbook.VBProject.References.Item(i)
        If theRef.isbroken = True Then
            ThisWorkbook.VBProject.References.Remove theRef
        End If
    Next i

     'Clear any errors so that error trapping for GUID additions can be evaluated
    Err.Clear

     'Add the reference
    ThisWorkbook.VBProject.References.AddFromGuid _
    GUID:=strGUID, Major:=1, Minor:=0

     'If an error was encountered, inform the user
    Select Case Err.Number
    Case Is = 32813
         'Reference already in use.  No action necessary
    Case Is = vbNullString
         'Reference added without issue
    Case Else
         'An unknown error was encountered, so alert the user
        MsgBox "A problem was encountered trying to" & vbNewLine _
        & "add or remove a reference in this file" & vbNewLine & "Please check the " _
        & "references in your VBA project!", vbCritical + vbOKOnly, "Error!"
    End Select
    On Error GoTo 0
End Sub

Way 2 (Directly referencing the dll)

This code adds a reference to Microsoft VBScript Regular Expressions 5.5

Option Explicit

Sub AddReference()
    Dim VBAEditor As VBIDE.VBE
    Dim vbProj As VBIDE.VBProject
    Dim chkRef As VBIDE.Reference
    Dim BoolExists As Boolean

    Set VBAEditor = Application.VBE
    Set vbProj = ActiveWorkbook.VBProject

    '~~> Check if "Microsoft VBScript Regular Expressions 5.5" is already added
    For Each chkRef In vbProj.References
        If chkRef.Name = "VBScript_RegExp_55" Then
            BoolExists = True
            GoTo CleanUp
        End If
    Next

    vbProj.References.AddFromFile "C:\WINDOWS\system32\vbscript.dll\3"

CleanUp:
    If BoolExists = True Then
        MsgBox "Reference already exists"
    Else
        MsgBox "Reference Added Successfully"
    End If

    Set vbProj = Nothing
    Set VBAEditor = Nothing
End Sub

Note: I have not added Error Handling. It is recommended that in your actual code, do use it :)

EDIT Beaten by mischab1 :)

Excel: Search for a list of strings within a particular string using array formulas?

In case others may find this useful: I found that by adding an initial empty cell to my list of search terms, a zero value will be returned instead of error.

={INDEX(SearchTerms!$A$1:$A$38,MAX(IF(ISERROR(SEARCH(SearchTerms!$A$1:$A$38,SearchCell)),0,1)*((SearchTerms!$B$1:$B$38)+1)))}

NB: Column A has the search terms, B is the row number index.

How do I get my accordion to load with all the menus closed?

How to implement the Android ActionBar back button?

Following Steps are much enough to back button:

Step 1: This code should be in Manifest.xml

<activity android:name=".activity.ChildActivity"
        android:parentActivityName=".activity.ParentActivity"
        android:screenOrientation="portrait">
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value=".activity.ParentActivity" /></activity>

Step 2: You won't give

finish();

in your Parent Activity while starting Child Activity.

Step 3: If you need to come back to Parent Activity from Child Activity, Then you just give this code for Child Activity.

startActivity(new Intent(ParentActivity.this, ChildActivity.class));

Programs & Examples On #Amfphp

What is simplest way to read a file into String?

how to format date in Component of angular 5

List changes unexpectedly after assignment. How do I clone or copy it to prevent this?

Verify host key with pysftp

ActionBarActivity is deprecated

How is length implemented in Java Arrays?

Post to another page within a PHP script

Javascript: Load an Image from url and display

var functionName = function() {} vs function functionName() {}

Check if a String contains numbers Java

How to timeout a thread

Is it possible to modify a registry entry via a .bat/.cmd script?

Does hosts file exist on the iPhone? How to change it?

How can I get a List from some class properties with Java 8 Stream?

Uncaught TypeError: Object #<Object> has no method 'movingBoxes'

How to update Pandas from Anaconda and is it possible to use eclipse with this last

Read and write into a file using VBScript

How to change font-size of a tag using inline css?

How can I parse a CSV string with JavaScript, which contains comma in data?

Append text to textarea with javascript

SQL Error: ORA-01861: literal does not match format string 01861

Linq to Entities - SQL "IN" clause

Javascript document.getElementById("id").value returning null instead of empty string when the element is an empty text box

Delete topic in Kafka 0.8.1.1

Using .otf fonts on web browsers

Getting time and date from timestamp with php

Export tables to an excel spreadsheet in same directory

Accessing value inside nested dictionaries

How can I open a website in my web browser using Python?

Is there an upper bound to BigInteger?

What does 'stale file handle' in Linux mean?

Redeploy alternatives to JRebel

#1130 - Host ‘localhost’ is not allowed to connect to this MySQL server

Can't access 127.0.0.1

How to tell Jackson to ignore a field during serialization if its value is null?

Excel VBA: AutoFill Multiple Cells with Formulas

Why doesn't "System.out.println" work in Android?

Predicate in Java

mongodb group values by multiple fields

How to store a dataframe using Pandas

What are my options for storing data when using React Native? (iOS and Android)

jQuery scroll to element

How to use mongoose findOne

javascript - replace dash (hyphen) with a space

openCV program compile error "libopencv_core.so.2.4: cannot open shared object file: No such file or directory" in ubuntu 12.04

JavaScript: Global variables after Ajax requests

JPA Criteria API - How to add JOIN clause (as general sentence as possible)

pandas: best way to select all columns whose names start with X

How can I stop the browser back button using JavaScript?

How to sum digits of an integer in java?

Bootstrap 4 img-circle class not working

Parsing Query String in node.js

Passing an array to a query using a WHERE clause

Eclipse: How to install a plugin manually?

XmlWriter to Write to a String Instead of to a File

How can I draw circle through XML Drawable - Android?

Now() function with time trim

How to access command line arguments of the caller inside a function?

"No such file or directory" error when executing a binary

Significance of ios_base::sync_with_stdio(false); cin.tie(NULL);

Why is "1000000000000000 in range(1000000000000001)" so fast in Python 3?

Change Volley timeout duration

What is the SQL command to return the field names of a table?

How to extract a value from a string using regex and a shell?

What is the __del__ method, How to call it?

Android dex gives a BufferOverflowException when building

What are the dark corners of Vim your mom never told you about?

Playing .mp3 and .wav in Java?

android.view.InflateException: Binary XML file line #12: Error inflating class <unknown>

How to find whether a number belongs to a particular range in Python?

HTML img align="middle" doesn't align an image

DropDownList in MVC 4 with Razor

Get key from a HashMap using the value

Tkinter module not found on Ubuntu

How do I get a python program to do nothing?

How can I extract a good quality JPEG image from a video file with ffmpeg?

How to display an alert box from C# in ASP.NET?

Is there a way to use use text as the background with CSS?

What is the difference between persist() and merge() in JPA and Hibernate?

What is the del method, How to call it?