Programs & Examples On #Lnk2001

error LNK2038: mismatch detected for '_MSC_VER': value '1600' doesn't match value '1700' in CppFile1.obj

for each project in your solution make sure that

Properties > Config. Properties > General > Platform Toolset

is one for all of them, v100 for visual studio 2010, v110 for visual studio 2012

you also may be working on v100 from visual studio 2012

error LNK2001: unresolved external symbol (C++)

Sounds like you are using Microsoft Visual C++. If that is the case, then the most possibility is that you don't compile your two.cpp with one.cpp (one.cpp is the implementation for one.h).

If you are from command line (cmd.exe), then try this first: cl -o two.exe one.cpp two.cpp

If you are from IDE, right click on the project name from Solution Explore. Then choose Add, Existing Item.... Add one.cpp into your project.

Unresolved external symbol in object files

POINTERS

I had this problem and solved it by using pointer. I see that this wasn't your issue but I thought I'd mention it because I sure wish it had been here when I saw this an hour ago. My issue was about declaring a static member variable without defining it (the definition needed to come after some other set ups) and of course a pointer doesn't need a definition. Equally elementary mistake :P

jquery equivalent for JSON.stringify

There is no such functionality in jQuery. Use JSON.stringify or alternatively any jQuery plugin with similar functionality (e.g jquery-json).

PHP Echo a large block of text

Heredoc syntax can be very useful:

// start the string with 3 <'s and then a word
// it doesn't have to be any particular string or length
// but it's common to make it in all caps.
echo <<< EOT
    in here is your string
    it has the same variable substitution rules
    as a double quoted string.
    when you end it, put the indicator word at the
    start of the line (no spaces before it)
    and put a semicolon after it
EOT;

How to check for registry value using VbScript

This should work for you:

Dim oShell
Dim iValue

Set oShell = CreateObject("WScript.Shell")

iValue = oShell.RegRead("HKLM\SOFTWARE\SOMETHINGSOMETHING")

Center a 'div' in the middle of the screen, even when the page is scrolled up or down?

Correct Method is

.PopupPanel
{
    border: solid 1px black;
    position: fixed;
    left: 50%;
    top: 50%;
    background-color: white;
    z-index: 100;
    height: 400px;
    margin-top: -200px;

    width: 600px;
    margin-left: -300px;
}

PHP foreach loop key value

As Pekka stated above

foreach ($array as $key => $value)

Also you might want to try a recursive function

displayRecursiveResults($site);

function displayRecursiveResults($arrayObject) {
    foreach($arrayObject as $key=>$data) {
        if(is_array($data)) {
            displayRecursiveResults($data);
        } elseif(is_object($data)) {
            displayRecursiveResults($data);
        } else {
            echo "Key: ".$key." Data: ".$data."<br />";
        }
    }
}

How can I get a web site's favicon?

You can use Getfv.co :

To retrieve a favicon you can hotlink it at... http://g.etfv.co/[URL]

Example for this page : http://g.etfv.co/https://stackoverflow.com/questions/5119041/how-can-i-get-a-web-sites-favicon

Download content and let's go !

Edit :

Getfv.co and fvicon.com look dead. If you want I found a non free alternative : grabicon.com.

Get local IP address

Pre requisites: you have to add System.Data.Linq reference and refer it

using System.Linq;
string ipAddress ="";
IPHostEntry ipHostInfo = Dns.GetHostEntry(Dns.GetHostName());
ipAddress = Convert.ToString(ipHostInfo.AddressList.FirstOrDefault(address => address.AddressFamily == AddressFamily.InterNetwork));

Regex to validate date format dd/mm/yyyy

Further extended the regex given by @AlokChaudhary to support:

1. dd mmm YYYY (in addition to dd-mmm-YYYY, dd/mmm/YYYY, dd.mmm.YYYY).

2. mmm in all CAPITAL LETTERS format (in addition to Title format)

dd mmm YYYY e.g. 30 Apr 2026 or 24 DEC 2028 are popular.

Extended regex:

(^(?:(?:(?:31(?:(?:([-.\/])(?:0?[13578]|1[02])\1)|(?:([-.\/ ])(?:Jan|JAN|Mar|MAR|May|MAY|Jul|JUL|Aug|AUG|Oct|OCT|Dec|DEC)\2)))|(?:(?:29|30)(?:(?:([-.\/])(?:0?[13-9]|1[0-2])\3)|(?:([-.\/ ])(?:Jan|JAN|Mar|MAR|Apr|APR|May|MAY|Jun|JUN|Jul|JUL|Aug|AUG|Sep|SEP|Oct|OCT|Nov|NOV|Dec|DEC)\4))))(?:(?:1[6-9]|[2-9]\d)?\d{2}))$|^(?:29(?:(?:([-.\/])(?:0?2)\5)|(?:([-.\/ ])(?:Feb|FEB)\6))(?:(?:1[6-9]|[2-9]\d)?(?:0[48]|[2468][048]|[13579][26])|(?:(?:16|[2468][048]|[3579][26])00)))$|^(?:(?:0?[1-9]|1\d|2[0-8])(?:(?:([-.\/])(?:(?:0?[1-9]|(?:1[0-2])))\7)|(?:([-.\/ ])(?:Jan|JAN|Feb|FEB|Mar|MAR|May|MAY|Jul|JUL|Aug|AUG|Oct|OCT|Dec|DEC)\8))(?:(?:1[6-9]|[2-9]\d)?\d{2}))$)

Test cases included in the Regex Demo

Features (retained):

  • Leap year checking (Feb 29 validation) includes the logics: (divisible by 4 but not divisible by 100) or (divisible by 400)
  • Supports years 1600 ~ 9999
  • Supports dd/mm/YYYY, dd-mm-YYYY, dd.mm.YYYY (but not dd mm YYYY)
  • Supports dd mmm YYYY, dd-mmm-YYYY, dd/mmm/YYYY, dd.mmm.YYYY (dd mmm YYYY newly added. mmm can be in CAPITAL e.g. DEC or Title format e.g. Dec)

Some additional minor touch-up as follows:

  1. Included the fix by Ofir Luzon on February 14th 2019 to remove a comma that was in the regex which allowed dates like 29-0,-11 [error replicated to Alok Chaudhary's regex]

  2. Replaced (\/|-|\.) by ([-.\/]) to minimize the use of backslash. \/ is still used in order to support some regex flavor e.g. PCRE(PHP) although some other regex flavor e.g. Python can simply use / inside the character class [ ]

  3. Added a pair of parenthesis () surrounding the whole regex to make it a capturing group for the whole matching string. This is useful for people using findAll type of functions to get a matching item list (e.g. re.findall in Python). This enable us to capture all the matching strings within a mult-line string with the following codes:

re.findall sample codes:

match_list = re.findall(regex, source_string)
for item in match_list:
    print(item[0])

Extended regex image: enter image description here

Credits should go to Ofir Luzon and Alok Chaudhary who created such excellent regexes for us all!

How to force JS to do math instead of putting two strings together

I'm adding this answer because I don't see it here.

One way is to put a '+' character in front of the value

example:

var x = +'11.5' + +'3.5'

x === 15

I have found this to be the simplest way

In this case, the line:

dots = document.getElementById("txt").value;

could be changed to

dots = +(document.getElementById("txt").value);

to force it to a number

NOTE:

+'' === 0
+[] === 0
+[5] === 5
+['5'] === 5

sorting a List of Map<String, String>

You should implement a Comparator<Map<String, String>> which basically extracts the "name" value from the two maps it's passed, and compares them.

Then use Collections.sort(list, comparator).

Are you sure a Map<String, String> is really the best element type for your list though? Perhaps you should have another class which contains a Map<String, String> but also has a getName() method?

PHP to search within txt file and echo the whole line

one way...

$needle = "blah";
$content = file_get_contents('file.txt');
preg_match('~^(.*'.$needle.'.*)$~',$content,$line);
echo $line[1];

though it would probably be better to read it line by line with fopen() and fread() and use strpos()

Redis command to get all available keys?

You can simply connect to your redis server using redis-cli, select your database and type KEYS *, please remember it will give you all the keys present in selected redis database.

How can I get a specific parameter from location.search?

The following uses regular expressions and searches only on the query string portion of the URL.

Most importantly, this method supports normal and array parameters as in http://localhost/?fiz=zip&foo[]=!!=&bar=7890#hashhashhash

function getQueryParam(param) {
    var result =  window.location.search.match(
        new RegExp("(\\?|&)" + param + "(\\[\\])?=([^&]*)")
    );

    return result ? result[3] : false;
}

console.log(getQueryParam("fiz"));
console.log(getQueryParam("foo"));
console.log(getQueryParam("bar"));
console.log(getQueryParam("zxcv"));

Output:

zip
!!=
7890
false

Xml Parsing in C#

First add an Enrty and Category class:

public class Entry {     public string Id { get; set; }     public string Title { get; set; }     public string Updated { get; set; }     public string Summary { get; set; }     public string GPoint { get; set; }     public string GElev { get; set; }     public List<string> Categories { get; set; } }  public class Category {     public string Label { get; set; }     public string Term { get; set; } } 

Then use LINQ to XML

XDocument xDoc = XDocument.Load("path");          List<Entry> entries = (from x in xDoc.Descendants("entry")             select new Entry()             {                 Id = (string) x.Element("id"),                 Title = (string)x.Element("title"),                 Updated = (string)x.Element("updated"),                 Summary = (string)x.Element("summary"),                 GPoint = (string)x.Element("georss:point"),                 GElev = (string)x.Element("georss:elev"),                 Categories = (from c in x.Elements("category")                                   select new Category                                   {                                       Label = (string)c.Attribute("label"),                                       Term = (string)c.Attribute("term")                                   }).ToList();             }).ToList(); 

Replacing values from a column using a condition in R

# reassign depth values under 10 to zero
df$depth[df$depth<10] <- 0

(For the columns that are factors, you can only assign values that are factor levels. If you wanted to assign a value that wasn't currently a factor level, you would need to create the additional level first:

levels(df$species) <- c(levels(df$species), "unknown") 
df$species[df$depth<10]  <- "unknown" 

How to resolve conflicts in EGit

To resolve the conflicts, use Git stash to save away your uncommitted changes; then pull down the remote repository change set; then pop your local stash to reapply your uncommitted changes.

In Eclipse v4.5 (Mars) to stash changes (a relatively recent addition, wasn't in previous EGit) I do this: right-click on a top-level Eclipse project that's in Git control, pick Team, pick Stashes, pick Stash Changes; a dialog opens to request a stash commit message.

You must use the context menu on a top level project! If I right click on a directory or file within a Git-controlled project I don't get the appropriate context menu.

How can I have grep not print out 'No such file or directory' errors?

I redirect stderr to stdout and then use grep's invert-match (-v) to exclude the warning/error string that I want to hide:

grep -r <pattern> * 2>&1 | grep -v "No such file or directory"

Disable validation of HTML5 form elements

Just use novalidate in your form.

<form name="myForm" role="form" novalidate class="form-horizontal" ng-hide="formMain">

Cheers!!!

How to remove single character from a String

To Remove a Single character from The Given String please find my method hope it will be usefull. i have used str.replaceAll to remove the string but their are many ways to remove a character from a given string but i prefer replaceall method.

Code For Remove Char:

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;


public class Removecharacter 
{

    public static void main(String[] args) 
    {
        String result = removeChar("Java", 'a');
        String result1 = removeChar("Edition", 'i');

         System.out.println(result + " " + result1);

    }


    public static String removeChar(String str, char c) {
        if (str == null)
        {
            return null;
        }
        else
        {   
        return str.replaceAll(Character.toString(c), "");
        }
    }


}

Console image :

please find The Attached image of console,

enter image description here

Thanks For Asking. :)

Windows CMD command for accessing usb?

Try this batch :

@echo off
Title List of connected external devices by Hackoo
Mode con cols=100 lines=20 & Color 9E
wmic LOGICALDISK where driveType=2 get deviceID > wmic.txt
for /f "skip=1" %%b IN ('type wmic.txt') DO (echo %%b & pause & Dir %%b)
Del wmic.txt
pause

Docker how to change repository name or rename image?

The accepted answer is great for single renames, but here is a way to rename multiple images that have the same repository all at once (and remove the old images).

If you have old images of the form:

$ docker images
REPOSITORY               TAG                 IMAGE ID            CREATED             SIZE
old_name/image_name_1    latest              abcdefghijk1        5 minutes ago      1.00GB
old_name/image_name_2    latest              abcdefghijk2        5 minutes ago      1.00GB

And you want:

new_name/image_name_1
new_name/image_name_2

Then you can use this (subbing in OLD_REPONAME, NEW_REPONAME, and TAG as appropriate):

OLD_REPONAME='old_name'
NEW_REPONAME='new_name'
TAG='latest'

# extract image name, e.g. "old_name/image_name_1"
for image in $(docker images | awk '{ if( FNR>1 ) { print $1 } }' | grep $OLD_REPONAME)
do \
  OLD_NAME="${image}:${TAG}" && \
  NEW_NAME="${NEW_REPONAME}${image:${#OLD_REPONAME}:${#image}}:${TAG}" && \
  docker image tag $OLD_NAME $NEW_NAME && \
  docker rmi $image:${TAG}  # omit this line if you want to keep the old image
done

Javascript loop through object array?

All the answers provided here uses normal function but these days most of our code uses arrow functions in ES6. I hope my answer will help readers on how to use arrow function when we do iteration over array of objects

let data = {
      "messages": [{
           "msgFrom": "13223821242",
           "msgBody": "Hi there"
       }, {
          "msgFrom": "Bill",
          "msgBody": "Hello!"
       }]
 }

Do .forEach on array using arrow function

 data.messages.forEach((obj, i) => {
     console.log("msgFrom", obj.msgFrom);
     console.log("msgBody", obj.msgBody);
 });

Do .map on array using arrow function

 data.messages.map((obj, i) => {
     console.log("msgFrom", obj.msgFrom);
     console.log("msgBody", obj.msgBody);
 });

Python Turtle, draw text with on screen with larger font

Use the optional font argument to turtle.write(), from the docs:

turtle.write(arg, move=False, align="left", font=("Arial", 8, "normal"))
 Parameters:

  • arg – object to be written to the TurtleScreen
  • move – True/False
  • align – one of the strings “left”, “center” or right”
  • font – a triple (fontname, fontsize, fonttype)

So you could do something like turtle.write("messi fan", font=("Arial", 16, "normal")) to change the font size to 16 (default is 8).

CSS checkbox input styling

Although CSS does provide a way for you to do the style specific to the checkbox type or another type, there are going to be problems with browsers that do not support this.

I think your only option in this case is going to be to apply classes to your checkboxes.

just add the class="checkbox" to your checkboxes.

Then create that style in your css code.

One thing you could do is this:

main.css

input[type="checkbox"] { /* css code here */ }

ie.css

.checkbox{ /* css code here for ie */ }

Then use the IE specific css include:

<!--[if lt IE 7]>
   <link rel="stylesheet" type="text/css" href="ie.css" />
<![endif]-->

You will still need to add the class for it to work in IE, and it will not work in other non-IE browsers that do not support IE. But it will make your website forward-thinking with css code and as IE gets support, you will be able to remove the ie specific css code and also the css classes from the checkboxes.

CSS @media print issues with background-color;

Best "solution" I have found is to provide a prominent "Print" button or link which pops up a small dialogue box explaining boldly, briefly and concisely that they need to adjust printer settings (with an ABC 123 bullet point instruction) to enable background and image printing. This has been very successful for me.

How to add click event to a iframe with JQuery

Try using this : iframeTracker jQuery Plugin, like that :

jQuery(document).ready(function($){
    $('.iframe_wrap iframe').iframeTracker({
        blurCallback: function(){
            // Do something when iframe is clicked (like firing an XHR request)
        }
    });
});

How to split and modify a string in NodeJS?

If you're using lodash and in the mood for a too-cute-for-its-own-good one-liner:

_.map(_.words('123, 124, 234,252'), _.add.bind(1, 1));

It's surprisingly robust thanks to lodash's powerful parsing capabilities.

If you want one that will also clean non-digit characters out of the string (and is easier to follow...and not quite so cutesy):

_.chain('123, 124, 234,252, n301')
   .replace(/[^\d,]/g, '')
   .words()
   .map(_.partial(_.add, 1))
   .value();

2017 edit:

I no longer recommend my previous solution. Besides being overkill and already easy to do without a third-party library, it makes use of _.chain, which has a variety of issues. Here's the solution I would now recommend:

const str = '123, 124, 234,252';
const arr = str.split(',').map(n => parseInt(n, 10) + 1);

My old answer is still correct, so I'll leave it for the record, but there's no need to use it nowadays.

$http get parameters does not work

The 2nd parameter in the get call is a config object. You want something like this:

$http
    .get('accept.php', {
        params: {
            source: link,
            category_id: category
        }
     })
     .success(function (data,status) {
          $scope.info_show = data
     });

See the Arguments section of http://docs.angularjs.org/api/ng.$http for more detail

How to retrieve a recursive directory and file list from PowerShell excluding some files and folders?

I like Keith Hill's answer except it has a bug that prevents it from recursing past two levels. These commands manifest the bug:

New-Item level1/level2/level3/level4/foobar.txt -Force -ItemType file
cd level1
GetFiles . xyz | % { $_.fullname }

With Hill's original code you get this:

...\level1\level2
...\level1\level2\level3

Here is a corrected, and slightly refactored, version:

function GetFiles($path = $pwd, [string[]]$exclude)
{
    foreach ($item in Get-ChildItem $path)
    {
        if ($exclude | Where {$item -like $_}) { continue }

        $item
        if (Test-Path $item.FullName -PathType Container)
        {
            GetFiles $item.FullName $exclude
        }
    }
} 

With that bug fix in place you get this corrected output:

...\level1\level2
...\level1\level2\level3
...\level1\level2\level3\level4
...\level1\level2\level3\level4\foobar.txt

I also like ajk's answer for conciseness though, as he points out, it is less efficient. The reason it is less efficient, by the way, is because Hill's algorithm stops traversing a subtree when it finds a prune target while ajk's continues. But ajk's answer also suffers from a flaw, one I call the ancestor trap. Consider a path such as this that includes the same path component (i.e. subdir2) twice:

\usr\testdir\subdir2\child\grandchild\subdir2\doc

Set your location somewhere in between, e.g. cd \usr\testdir\subdir2\child, then run ajk's algorithm to filter out the lower subdir2 and you will get no output at all, i.e. it filters out everything because of the presence of subdir2 higher in the path. This is a corner case, though, and not likely to be hit often, so I would not rule out ajk's solution due to this one issue.

Nonetheless, I offer here a third alternative, one that does not have either of the above two bugs. Here is the basic algorithm, complete with a convenience definition for the path or paths to prune--you need only modify $excludeList to your own set of targets to use it:

$excludeList = @("stuff","bin","obj*")
Get-ChildItem -Recurse | % {
    $pathParts = $_.FullName.substring($pwd.path.Length + 1).split("\");
    if ( ! ($excludeList | where { $pathParts -like $_ } ) ) { $_ }
}

My algorithm is reasonably concise but, like ajk's, it is less efficient than Hill's (for the same reason: it does not stop traversing subtrees at prune targets). However, my code has an important advantage over Hill's--it can pipeline! It is therefore amenable to fit into a filter chain to make a custom version of Get-ChildItem while Hill's recursive algorithm, through no fault of its own, cannot. ajk's algorithm can be adapted to pipeline use as well, but specifying the item or items to exclude is not as clean, being embedded in a regular expression rather than a simple list of items that I have used.

I have packaged my tree pruning code into an enhanced version of Get-ChildItem. Aside from my rather unimaginative name--Get-EnhancedChildItem--I am excited about it and have included it in my open source Powershell library. It includes several other new capabilities besides tree pruning. Furthermore, the code is designed to be extensible: if you want to add a new filtering capability, it is straightforward to do. Essentially, Get-ChildItem is called first, and pipelined into each successive filter that you activate via command parameters. Thus something like this...

Get-EnhancedChildItem –Recurse –Force –Svn
    –Exclude *.txt –ExcludeTree doc*,man -FullName -Verbose 

... is converted internally into this:

Get-ChildItem | FilterExcludeTree | FilterSvn | FilterFullName

Each filter must conform to certain rules: accepting FileInfo and DirectoryInfo objects as inputs, generating the same as outputs, and using stdin and stdout so it may be inserted in a pipeline. Here is the same code refactored to fit these rules:

filter FilterExcludeTree()
{
  $target = $_
  Coalesce-Args $Path "." | % {
    $canonicalPath = (Get-Item $_).FullName
    if ($target.FullName.StartsWith($canonicalPath)) {
      $pathParts = $target.FullName.substring($canonicalPath.Length + 1).split("\");
      if ( ! ($excludeList | where { $pathParts -like $_ } ) ) { $target }
    }
  }
} 

The only additional piece here is the Coalesce-Args function (found in this post by Keith Dahlby), which merely sends the current directory down the pipe in the event that the invocation did not specify any paths.

Because this answer is getting somewhat lengthy, rather than go into further detail about this filter, I refer the interested reader to my recently published article on Simple-Talk.com entitled Practical PowerShell: Pruning File Trees and Extending Cmdlets where I discuss Get-EnhancedChildItem at even greater length. One last thing I will mention, though, is another function in my open source library, New-FileTree, that lets you generate a dummy file tree for testing purposes so you can exercise any of the above algorithms. And when you are experimenting with any of these, I recommend piping to % { $_.fullname } as I did in the very first code fragment for more useful output to examine.

How to apply box-shadow on all four sides?

I found the http://css-tricks.com/forums/topic/how-to-add-shadows-on-all-4-sides-of-a-block-with-css/ site.

.allSides
{
    width:350px;height:200px;
    border: solid 1px #555;
    background-color: #eed;
    box-shadow: 0 0 10px rgba(0,0,0,0.6);
    -moz-box-shadow: 0 0 10px rgba(0,0,0,0.6);
    -webkit-box-shadow: 0 0 10px rgba(0,0,0,0.6);
    -o-box-shadow: 0 0 10px rgba(0,0,0,0.6);
}

python JSON only get keys in first level

A good way to check whether a python object is an instance of a type is to use isinstance() which is Python's 'built-in' function. For Python 3.6:

dct = {
       "1": "a", 
       "3": "b", 
       "8": {
            "12": "c", 
            "25": "d"
           }
      }

for key in dct.keys():
    if isinstance(dct[key], dict)== False:
       print(key, dct[key])
#shows:
# 1 a
# 3 b

How to get a index value from foreach loop in jstl

You can use the varStatus attribute like this:-

<c:forEach var="categoryName" items="${categoriesList}" varStatus="myIndex">

myIndex.index will give you the index. Here myIndex is a LoopTagStatus object.

Hence, you can send that to your javascript method like this:-

<a onclick="getCategoryIndex(${myIndex.index})" href="#">${categoryName}</a>

Access denied for user 'homestead'@'localhost' (using password: YES)

Check your ".env" file in the root folder. is it correct?

DB_CONNECTION=mysql
DB_HOST=127.0.0.1
DB_PORT=3306
DB_DATABASE=homestead
DB_USERNAME=homestead
DB_PASSWORD=secret

How can I extract a number from a string in JavaScript?

You need to add "(/\d+/g)" which will remove all non-number text, but it will still be a string at this point. If you create a variable and "parseInt" through the match, you can set the new variables to the array values. Here is an example of how I got it to work:

    var color = $( this ).css( "background-color" );
    var r = parseInt(color.match(/\d+/g)[0]);
    var g = parseInt(color.match(/\d+/g)[1]);
    var b = parseInt(color.match(/\d+/g)[2]);

How to check Oracle database for long running queries

Step 1:Execute the query

column username format 'a10'
column osuser format 'a10'
column module format 'a16'
column program_name format 'a20'
column program format 'a20'
column machine format 'a20'
column action format 'a20'
column sid format '9999'
column serial# format '99999'
column spid format '99999'
set linesize 200
set pagesize 30
select
a.sid,a.serial#,a.username,a.osuser,c.start_time,
b.spid,a.status,a.machine,
a.action,a.module,a.program
from
v$session a, v$process b, v$transaction c,
v$sqlarea s
Where
a.paddr = b.addr
and a.saddr = c.ses_addr
and a.sql_address = s.address (+)
and to_date(c.start_time,'mm/dd/yy hh24:mi:ss') <= sysdate - (15/1440) -- running for 15 minutes
order by c.start_time
/   

Step 2: desc v$session

Step 3:select sid, serial#,SQL_ADDRESS, status,PREV_SQL_ADDR from v$session where sid='xxxx' //(enter the sid value)

Step 4: select sql_text from v$sqltext where address='XXXXXXXX';

Step 5: select piece, sql_text from v$sqltext where address='XXXXXX' order by piece;

How to properly apply a lambda function into a pandas data frame column

You need mask:

sample['PR'] = sample['PR'].mask(sample['PR'] < 90, np.nan)

Another solution with loc and boolean indexing:

sample.loc[sample['PR'] < 90, 'PR'] = np.nan

Sample:

import pandas as pd
import numpy as np

sample = pd.DataFrame({'PR':[10,100,40] })
print (sample)
    PR
0   10
1  100
2   40

sample['PR'] = sample['PR'].mask(sample['PR'] < 90, np.nan)
print (sample)
      PR
0    NaN
1  100.0
2    NaN
sample.loc[sample['PR'] < 90, 'PR'] = np.nan
print (sample)
      PR
0    NaN
1  100.0
2    NaN

EDIT:

Solution with apply:

sample['PR'] = sample['PR'].apply(lambda x: np.nan if x < 90 else x)

Timings len(df)=300k:

sample = pd.concat([sample]*100000).reset_index(drop=True)

In [853]: %timeit sample['PR'].apply(lambda x: np.nan if x < 90 else x)
10 loops, best of 3: 102 ms per loop

In [854]: %timeit sample['PR'].mask(sample['PR'] < 90, np.nan)
The slowest run took 4.28 times longer than the fastest. This could mean that an intermediate result is being cached.
100 loops, best of 3: 3.71 ms per loop

End of File (EOF) in C

EOF is -1 because that's how it's defined. The name is provided by the standard library headers that you #include. They make it equal to -1 because it has to be something that can't be mistaken for an actual byte read by getchar(). getchar() reports the values of actual bytes using positive number (0 up to 255 inclusive), so -1 works fine for this.

The != operator means "not equal". 0 stands for false, and anything else stands for true. So what happens is, we call the getchar() function, and compare the result to -1 (EOF). If the result was not equal to EOF, then the result is true, because things that are not equal are not equal. If the result was equal to EOF, then the result is false, because things that are equal are not (not equal).

The call to getchar() returns EOF when you reach the "end of file". As far as C is concerned, the 'standard input' (the data you are giving to your program by typing in the command window) is just like a file. Of course, you can always type more, so you need an explicit way to say "I'm done". On Windows systems, this is control-Z. On Unix systems, this is control-D.

The example in the book is not "wrong". It depends on what you actually want to do. Reading until EOF means that you read everything, until the user says "I'm done", and then you can't read any more. Reading until '\n' means that you read a line of input. Reading until '\0' is a bad idea if you expect the user to type the input, because it is either hard or impossible to produce this byte with a keyboard at the command prompt :)

How do I change the UUID of a virtual disk?

The correct command is the following one.

VBoxManage internalcommands sethduuid "/home/user/VirtualBox VMs/drupal/drupal.vhd"

The path for the virtual disk contains a space, so it must be enclosed in double quotes to avoid it is parsed as two parameters.

Is "&#160;" a replacement of "&nbsp;"?

&#160; is the numeric reference for the entity reference &nbsp; — they are the exact same thing. It's likely your editor is simply inserting the numberic reference instead of the named one.

See the Wikipedia page for the non-breaking space.

Custom bullet symbol for <li> elements in <ul> that is a regular character, and not an image

_x000D_
_x000D_
.single-before {_x000D_
  list-style: "";_x000D_
  list-style-position: outside!important;_x000D_
}
_x000D_
<ul class="single-before">_x000D_
  <li> is to manifest perfection already in man.</li>_x000D_
  <li> is to bring out the best facets of our students personalities.</li>_x000D_
</ul>
_x000D_
_x000D_
_x000D_

How to format DateTime in Flutter , How to get current time in flutter?

With this approach, there is no need to import any library.

DateTime now = DateTime.now();

String convertedDateTime = "${now.year.toString()}-${now.month.toString().padLeft(2,'0')}-${now.day.toString().padLeft(2,'0')} ${now.hour.toString()}-${now.minute.toString()}";

Output

2020-12-05 14:57

Append text to file from command line without using io redirection

You can use the --append feature of tee:

cat file01.txt | tee --append bothFiles.txt 
cat file02.txt | tee --append bothFiles.txt 

Or shorter,

cat file01.txt file02.txt | tee --append bothFiles.txt 

I assume the request for no redirection (>>) comes from the need to use this in xargs or similar. So if that doesn't count, you can mute the output with >/dev/null.

What is a good practice to check if an environmental variable exists or not?

In case you want to check if multiple env variables are not set, you can do the following:

import os

MANDATORY_ENV_VARS = ["FOO", "BAR"]

for var in MANDATORY_ENV_VARS:
    if var not in os.environ:
        raise EnvironmentError("Failed because {} is not set.".format(var))

How do I get the App version and build number using Swift?

I also know this has already been answered but I wrapped up the previous answers:

(*)Updated for extensions

extension Bundle {
    var releaseVersionNumber: String? {
        return infoDictionary?["CFBundleShortVersionString"] as? String
    }
    var buildVersionNumber: String? {
        return infoDictionary?["CFBundleVersion"] as? String
    }
    var releaseVersionNumberPretty: String {
        return "v\(releaseVersionNumber ?? "1.0.0")"
    }
}

Usage:

someLabel.text = Bundle.main.releaseVersionNumberPretty

@Deprecated: Old answers

Swift 3.1:

class func getVersion() -> String {
    guard let version = Bundle.main.infoDictionary?["CFBundleShortVersionString"] as? String else {
        return "no version info"
    }
    return version
}

For older versions:

class func getVersion() -> String {
    if let version = NSBundle.mainBundle().infoDictionary?["CFBundleShortVersionString"] as? String {
        return version
    }
    return "no version info"
}

So if you want to set label text or want to use somewhere else;

self.labelVersion.text = getVersion()

How to replace blank (null ) values with 0 for all records?

I just had this same problem, and I ended up finding the simplest solution which works for my needs. In the table properties, I set the default value to 0 for the fields that I don't want to show nulls. Super easy.

Are there benefits of passing by pointer over passing by reference in C++?

Allen Holub's "Enough Rope to Shoot Yourself in the Foot" lists the following 2 rules:

120. Reference arguments should always be `const`
121. Never use references as outputs, use pointers

He lists several reasons why references were added to C++:

  • they are necessary to define copy constructors
  • they are necessary for operator overloads
  • const references allow you to have pass-by-value semantics while avoiding a copy

His main point is that references should not be used as 'output' parameters because at the call site there's no indication of whether the parameter is a reference or a value parameter. So his rule is to only use const references as arguments.

Personally, I think this is a good rule of thumb as it makes it more clear when a parameter is an output parameter or not. However, while I personally agree with this in general, I do allow myself to be swayed by the opinions of others on my team if they argue for output parameters as references (some developers like them immensely).

how to read all files inside particular folder

    using System.IO;
    string[] arr=Directory.GetFiles("folderpath","*.Fileextension");
      foreach(string file in arr)
       {

       }

Best way to Bulk Insert from a C# DataTable

Here's how I do it using a DataTable. This is a working piece of TEST code.

using (SqlConnection con = new SqlConnection(connStr))
{
    con.Open();

    // Create a table with some rows. 
    DataTable table = MakeTable();

    // Get a reference to a single row in the table. 
    DataRow[] rowArray = table.Select();

    using (SqlBulkCopy bulkCopy = new SqlBulkCopy(con))
    {
        bulkCopy.DestinationTableName = "dbo.CarlosBulkTestTable";

        try
        {
            // Write the array of rows to the destination.
            bulkCopy.WriteToServer(rowArray);
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }

    }

}//using

How to retrieve the last autoincremented ID from a SQLite table?

I've had issues with using SELECT last_insert_rowid() in a multithreaded environment. If another thread inserts into another table that has an autoinc, last_insert_rowid will return the autoinc value from the new table.

Here's where they state that in the doco:

If a separate thread performs a new INSERT on the same database connection while the sqlite3_last_insert_rowid() function is running and thus changes the last insert rowid, then the value returned by sqlite3_last_insert_rowid() is unpredictable and might not equal either the old or the new last insert rowid.

That's from sqlite.org doco

How to move table from one tablespace to another in oracle 11g

Try this:-

ALTER TABLE <TABLE NAME to be moved> MOVE TABLESPACE <destination TABLESPACE NAME>

Very nice suggestion from IVAN in comments so thought to add in my answer

Note: this will invalidate all table's indexes. So this command is usually followed by

alter index <owner>."<index_name>" rebuild;

Equivalent of Oracle's RowID in SQL Server

Several of the answers above will work around the lack of a direct reference to a specific row, but will not work if changes occur to the other rows in a table. That is my criteria for which answers fall technically short.

A common use of Oracle's ROWID is to provide a (somewhat) stable method of selecting rows and later returning to the row to process it (e.g., to UPDATE it). The method of finding a row (complex joins, full-text searching, or browsing row-by-row and applying procedural tests against the data) may not be easily or safely re-used to qualify the UPDATE statement.

The SQL Server RID seems to provide the same functionality, but does not provide the same performance. That is the only issue I see, and unfortunately the purpose of retaining a ROWID is to avoid repeating an expensive operation to find the row in, say, a very large table. Nonetheless, performance for many cases is acceptable. If Microsoft adjusts the optimizer in a future release, the performance issue could be addressed.

It is also possible to simply use FOR UPDATE and keep the CURSOR open in a procedural program. However, this could prove expensive in large or complex batch processing.

Caveat: Even Oracle's ROWID would not be stable if the DBA, between the SELECT and the UPDATE, for example, were to rebuild the database, because it is the physical row identifier. So the ROWID device should only be used within a well-scoped task.

How to save a spark DataFrame as csv on disk?

Apache Spark does not support native CSV output on disk.

You have four available solutions though:

  1. You can convert your Dataframe into an RDD :

    def convertToReadableString(r : Row) = ???
    df.rdd.map{ convertToReadableString }.saveAsTextFile(filepath)
    

    This will create a folder filepath. Under the file path, you'll find partitions files (e.g part-000*)

    What I usually do if I want to append all the partitions into a big CSV is

    cat filePath/part* > mycsvfile.csv
    

    Some will use coalesce(1,false) to create one partition from the RDD. It's usually a bad practice, since it may overwhelm the driver by pulling all the data you are collecting to it.

    Note that df.rdd will return an RDD[Row].

  2. With Spark <2, you can use databricks spark-csv library:

    • Spark 1.4+:

      df.write.format("com.databricks.spark.csv").save(filepath)
      
    • Spark 1.3:

      df.save(filepath,"com.databricks.spark.csv")
      
  3. With Spark 2.x the spark-csv package is not needed as it's included in Spark.

    df.write.format("csv").save(filepath)
    
  4. You can convert to local Pandas data frame and use to_csv method (PySpark only).

Note: Solutions 1, 2 and 3 will result in CSV format files (part-*) generated by the underlying Hadoop API that Spark calls when you invoke save. You will have one part- file per partition.

Kotlin Android start new Activity

You have to give the second argument of class type. You can also have it a little bit more tidy like below.

startActivity(Intent(this, Page2::class.java).apply {
    putExtra("extra_1", value1)
    putExtra("extra_2", value2)
    putExtra("extra_3", value3)
})

Android basics: running code in the UI thread

I like the one from HPP comment, it can be used anywhere without any parameter:

new Handler(Looper.getMainLooper()).post(new Runnable() {
    @Override
    public void run() {
        Log.d("UI thread", "I am the UI thread");
    }
});

Get a list of all the files in a directory (recursive)

This is what I came up with for a gradle build script:

task doLast {
    ext.FindFile = { list, curPath ->
        def files = file(curPath).listFiles().sort()

        files.each {  File file ->

            if (file.isFile()) {
                list << file
            }
            else {
                list << file  // If you want the directories in the list

                list = FindFile( list, file.path) 
            }
        }
        return list
    }

    def list = []
    def theFile = FindFile(list, "${project.projectDir}")

    list.each {
        println it.path
    }
}

How can I get an object's absolute position on the page in Javascript?

I would definitely suggest using element.getBoundingClientRect().

https://developer.mozilla.org/en-US/docs/Web/API/element.getBoundingClientRect

Summary

Returns a text rectangle object that encloses a group of text rectangles.

Syntax

var rectObject = object.getBoundingClientRect();

Returns

The returned value is a TextRectangle object which is the union of the rectangles returned by getClientRects() for the element, i.e., the CSS border-boxes associated with the element.

The returned value is a TextRectangle object, which contains read-only left, top, right and bottom properties describing the border-box, in pixels, with the top-left relative to the top-left of the viewport.

Here's a browser compatibility table taken from the linked MDN site:

+---------------+--------+-----------------+-------------------+-------+--------+
|    Feature    | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
+---------------+--------+-----------------+-------------------+-------+--------+
| Basic support | 1.0    | 3.0 (1.9)       | 4.0               | (Yes) | 4.0    |
+---------------+--------+-----------------+-------------------+-------+--------+

It's widely supported, and is really easy to use, not to mention that it's really fast. Here's a related article from John Resig: http://ejohn.org/blog/getboundingclientrect-is-awesome/

You can use it like this:

var logo = document.getElementById('hlogo');
var logoTextRectangle = logo.getBoundingClientRect();

console.log("logo's left pos.:", logoTextRectangle.left);
console.log("logo's right pos.:", logoTextRectangle.right);

Here's a really simple example: http://jsbin.com/awisom/2 (you can view and edit the code by clicking "Edit in JS Bin" in the upper right corner).

Or here's another one using Chrome's console: Using element.getBoundingClientRect() in Chrome

Note:

I have to mention that the width and height attributes of the getBoundingClientRect() method's return value are undefined in Internet Explorer 8. It works in Chrome 26.x, Firefox 20.x and Opera 12.x though. Workaround in IE8: for width, you could subtract the return value's right and left attributes, and for height, you could subtract bottom and top attributes (like this).

Programmatically shut down Spring Boot application

The simplest way would be to inject the following object where you need to initiate the shutdown

ShutdownManager.java

import org.springframework.context.ApplicationContext;
import org.springframework.boot.SpringApplication;

@Component
class ShutdownManager {

    @Autowired
    private ApplicationContext appContext;

    /*
     * Invoke with `0` to indicate no error or different code to indicate
     * abnormal exit. es: shutdownManager.initiateShutdown(0);
     **/
    public void initiateShutdown(int returnCode){
        SpringApplication.exit(appContext, () -> returnCode);
    }
}

invalid new-expression of abstract class type

Another possible cause for future Googlers

I had this issue because a method I was trying to implement required a std::unique_ptr<Queue>(myQueue) as a parameter, but the Queue class is abstract. I solved that by using a QueuePtr(myQueue) constructor like so:

using QueuePtr = std::unique_ptr<Queue>;

and used that in the parameter list instead. This fixes it because the initializer tries to create a copy of Queue when you make a std::unique_ptr of its type, which can't happen.

How to save .xlsx data to file as a blob

Solution for me.

Step: 1

<a onclick="exportAsExcel()">Export to excel</a>

Step: 2

I'm using file-saver lib.

Read more: https://www.npmjs.com/package/file-saver

npm i file-saver

Step: 3

let FileSaver = require('file-saver'); // path to file-saver

function exportAsExcel() {
    let dataBlob = '...kAAAAFAAIcmtzaGVldHMvc2hlZXQxLnhtbFBLBQYAAAAACQAJAD8CAADdGAAAAAA='; // If have ; You should be split get blob data only
    this.downloadFile(dataBlob);
}

function downloadFile(blobContent){
    let blob = new Blob([base64toBlob(blobContent, 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet')], {});
    FileSaver.saveAs(blob, 'report.xlsx');
}

function base64toBlob(base64Data, contentType) {
    contentType = contentType || '';
    let sliceSize = 1024;
    let byteCharacters = atob(base64Data);
    let bytesLength = byteCharacters.length;
    let slicesCount = Math.ceil(bytesLength / sliceSize);
    let byteArrays = new Array(slicesCount);
    for (let sliceIndex = 0; sliceIndex < slicesCount; ++sliceIndex) {
        let begin = sliceIndex * sliceSize;
        let end = Math.min(begin + sliceSize, bytesLength);

        let bytes = new Array(end - begin);
        for (var offset = begin, i = 0; offset < end; ++i, ++offset) {
            bytes[i] = byteCharacters[offset].charCodeAt(0);
        }
        byteArrays[sliceIndex] = new Uint8Array(bytes);
    }
    return new Blob(byteArrays, { type: contentType });
}

Work for me. ^^

Python & Matplotlib: Make 3D plot interactive in Jupyter Notebook

There is a new library called ipyvolume that may do what you want, the documentation shows live demos. The current version doesn't do meshes and lines, but master from the git repo does (as will version 0.4). (Disclaimer: I'm the author)

How to find a text inside SQL Server procedures / triggers?

This will work for you:

use [ANALYTICS]  ---> put your DB name here
GO
SELECT sm.object_id, OBJECT_NAME(sm.object_id) AS object_name, o.type, o.type_desc, sm.definition
FROM sys.sql_modules AS sm
JOIN sys.objects AS o ON sm.object_id = o.object_id
where sm.definition like '%SEARCH_WORD_HERE%' collate SQL_Latin1_General_CP1_CI_AS
ORDER BY o.type;
GO

css h1 - only as wide as the text

align-self-start, align-self-center... in flexbox

.centercol h1{
    background: #F2EFE9;
    border-left: 3px solid #C6C1B8;
    color: #006BB6;
    display: block;
    align-self: center;
    font-weight: normal;
    font-size: 18px;
    padding: 3px 3px 3px 6px;
}

Prevent direct access to a php include file

You can also try renaming the document you don't want people to be able to access. You could rename it to 47d8498d3w.php for instance. Just make something up that people most likely won't type as a http-request. If you include the file with SSI or PHP, the user won't be able to see the name of the document anyway.

Environment variables in Mac OS X

There's no need for duplication. You can set environment variables used by launchd (and child processes, i.e. anything you start from Spotlight) using launchctl setenv.

For example, if you want to mirror your current path in launchd after setting it up in .bashrc or wherever:

PATH=whatever:you:want
launchctl setenv PATH $PATH

Environment variables are not automatically updated in running applications. You will need to relaunch applications to get the updated environment variables (although you can just set variables in your shell, e.g. PATH=whatever:you:want; there's no need to relaunch the terminal).

Download and install an ipa from self hosted url on iOS

More simply you can utilize DropBox for this. The steps basically remain the same. You can do the following-:

1) upload your .ipa to dropBox, Share the link for this .ipa

2) Paste the shared link for .ipa in your manifest.plist file , Upload manifest file in DropBox again share the link for this .plist file

3)paste the link for this Plist in your index.html file with a suitable tag.

Share this index.html file with anybody who can tap on the URL and download. or you can directly hit the URL instead.

How to filter a dictionary according to an arbitrary condition function?

dict((k, v) for k, v in points.items() if all(x < 5 for x in v))

You could choose to call .iteritems() instead of .items() if you're in Python 2 and points may have a lot of entries.

all(x < 5 for x in v) may be overkill if you know for sure each point will always be 2D only (in that case you might express the same constraint with an and) but it will work fine;-).

How can I set the form action through JavaScript?

Setting form action after selection of option using JavaScript

<script>
    function onSelectedOption(sel) {
        if ((sel.selectedIndex) == 0) {
            document.getElementById("edit").action =
            "http://www.example.co.uk/index.php";
            document.getElementById("edit").submit();
        }
        else
        {
            document.getElementById("edit").action =
            "http://www.example.co.uk/different.php";
            document.getElementById("edit").submit();
        }
    }
</script>

<form name="edit" id="edit" action="" method="GET">
    <input type="hidden" name="id" value="{ID}" />
</form>

<select name="option" id="option" onchange="onSelectedOption(this);">
    <option name="contactBuyer">Edit item</option>
    <option name="relist">End listing</option>
</select>

fatal error C1083: Cannot open include file: 'xyz.h': No such file or directory?

This problem can be easily solved by installing the following Individual components:

enter image description here

Execute raw SQL using Doctrine 2

You can't, Doctrine 2 doesn't allow for raw queries. It may seem like you can but if you try something like this:

$sql = "SELECT DATE_FORMAT(whatever.createdAt, '%Y-%m-%d') FORM whatever...";
$em = $this->getDoctrine()->getManager();
$em->getConnection()->exec($sql);

Doctrine will spit an error saying that DATE_FORMAT is an unknown function.

But my database (mysql) does know that function, so basically what is hapening is Doctrine is parsing that query behind the scenes (and behind your back) and finding an expression that it doesn't understand, considering the query to be invalid.

So if like me you want to be able to simply send a string to the database and let it deal with it (and let the developer take full responsibility for security), forget it.

Of course you could code an extension to allow that in some way or another, but you just as well off using mysqli to do it and leave Doctrine to it's ORM buisness.

What is difference between png8 and png24

While making image with fully transparent background in PNG-8, the outline of the image looks prominent with little white bits. But in PNG-24 the outline is gone and looks perfect. Transparency in PNG-24 is greater and cleaner than PNG-8.

PNG-8 contains 256 colors, while PNG-24 contains 16 million colors.

File size is almost double in PNG-24 than PNG-8.

Establish a VPN connection in cmd

I know this is a very old thread but I was looking for a solution to the same problem and I came across this before eventually finding the answer and I wanted to just post it here so somebody else in my shoes would have a shorter trek across the internet.

****Note that you probably have to run cmd.exe as an administrator for this to work**

So here we go, open up the prompt (as an adminstrator) and go to your System32 directory. Then run

C:\Windows\System32>cd ras

Now you'll be in the ras directory. Now it's time to create a temporary file with our connection info that we will then append onto the rasphone.pbk file that will allow us to use the rasdial command.

So to create our temp file run:

C:\Windows\System32\ras>copy con temp.txt

Now it will let you type the contents of the file, which should look like this:

[CONNECTION NAME]
MEDIA=rastapi
Port=VPN2-0
Device=WAN Miniport (IKEv2)
DEVICE=vpn
PhoneNumber=vpn.server.address.com

So replace CONNECTION NAME and vpn.server.address.com with the desired connection name and the vpn server address you want.

Make a new line and press Ctrl+Z to finish and save.

Now we will append this onto the rasphone.pbk file that may or may not exist depending on if you already have network connections configured or not. To do this we will run the following command:

C:\Windows\System32\ras>type temp.txt >> rasphone.pbk

This will append the contents of temp.txt to the end of rasphone.pbk, or if rasphone.pbk doesn't exist it will be created. Now we might as well delete our temp file:

C:\Windows\System32\ras>del temp.txt

Now we can connect to our newly configured VPN server with the following command:

C:\Windows\System32\ras>rasdial "CONNECTION NAME" myUsername myPassword

When we want to disconnect we can run:

C:\Windows\System32\ras>rasdial /DISCONNECT

That should cover it! I've included a direct copy and past from the command line of me setting up a connection for and connecting to a canadian vpn server with this method:

Microsoft Windows [Version 6.2.9200]
(c) 2012 Microsoft Corporation. All rights reserved.

C:\Windows\system32>cd ras

C:\Windows\System32\ras>copy con temp.txt
[Canada VPN Connection]
MEDIA=rastapi
Port=VPN2-0
Device=WAN Miniport (IKEv2)
DEVICE=vpn
PhoneNumber=ca.justfreevpn.com
^Z
        1 file(s) copied.

C:\Windows\System32\ras>type temp.txt >> rasphone.pbk

C:\Windows\System32\ras>del temp.txt

C:\Windows\System32\ras>rasdial "Canada VPN Connection" justfreevpn 2932
Connecting to Canada VPN Connection...
Verifying username and password...
Connecting to Canada VPN Connection...
Connecting to Canada VPN Connection...
Verifying username and password...
Registering your computer on the network...
Successfully connected to Canada VPN Connection.
Command completed successfully.

C:\Windows\System32\ras>rasdial /DISCONNECT
Command completed successfully.

C:\Windows\System32\ras>

Hope this helps.

java.lang.NoSuchMethodError: javax.servlet.ServletContext.getContextPath()Ljava/lang/String;

java.lang.NoSuchMethodError: javax.servlet.ServletContext.getContextPath()Ljava/lang/String;

That method was added in Servlet 2.5.

So this problem can have at least 3 causes:

  1. The servlet container does not support Servlet 2.5.
  2. The web.xml is not declared conform Servlet 2.5 or newer.
  3. The webapp's runtime classpath is littered with servlet container specific JAR files of a different servlet container make/version which does not support Servlet 2.5.

To solve it,

  1. Make sure that your servlet container supports at least Servlet 2.5. That are at least Tomcat 6, Glassfish 2, JBoss AS 4.1, etcetera. Tomcat 5.5 for example supports at highest Servlet 2.4. If you can't upgrade Tomcat, then you'd need to downgrade Spring to a Servlet 2.4 compatible version.
  2. Make sure that the root declaration of web.xml complies Servlet 2.5 (or newer, at least the highest whatever your target runtime supports). For an example, see also somewhere halfway our servlets wiki page.
  3. Make sure that you don't have any servlet container specific libraries like servlet-api.jar or j2ee.jar in /WEB-INF/lib or even worse, the JRE/lib or JRE/lib/ext. They do not belong there. This is a pretty common beginner's mistake in an attempt to circumvent compilation errors in an IDE, see also How do I import the javax.servlet API in my Eclipse project?.

How to encode the plus (+) symbol in a URL

Is you want a plus (+) symbol in the body you have to encode it as 2B.

For example: Try this

Angular2 @Input to a property with get/set

@Paul Cavacas, I had the same issue and I solved by setting the Input() decorator above the getter.

  @Input('allowDays')
  get in(): any {
    return this._allowDays;
  }

  //@Input('allowDays')
  // not working
  set in(val) {
    console.log('allowDays = '+val);
    this._allowDays = val;
  }

See this plunker: https://plnkr.co/edit/6miSutgTe9sfEMCb8N4p?p=preview

jQuery get the name of a select option

 $(this).attr("name") 

means the name of the select tag not option name.

To get option name

 $("#band_type_choices option:selected").attr('name');

php is null or empty?

NULL stands for a variable without value. To check if a variable is NULL you can either use is_null($var) or the comparison (===) with NULL. Both ways, however, generate a warning if the variable is not defined. Similar to isset($var) and empty($var), which can be used as functions.

var_dump(is_null($var)); // true
var_dump($var === null); // true
var_dump(empty($var)); // true

Read more in How to check if a variable is NULL in PHP?

How to calculate number of days between two given dates?

There is also a datetime.toordinal() method that was not mentioned yet:

import datetime
print(datetime.date(2008,9,26).toordinal() - datetime.date(2008,8,18).toordinal())  # 39

https://docs.python.org/3/library/datetime.html#datetime.date.toordinal

date.toordinal()

Return the proleptic Gregorian ordinal of the date, where January 1 of year 1 has ordinal 1. For any date object d, date.fromordinal(d.toordinal()) == d.

Seems well suited for calculating days difference, though not as readable as timedelta.days.

Is there a rule-of-thumb for how to divide a dataset into training and validation sets?

Suppose you have less data, I suggest to try 70%, 80% and 90% and test which is giving better result. In case of 90% there are chances that for 10% test you get poor accuracy.

tsc is not recognized as internal or external command

For me, by running Visual Studio Code as Administrator, the problem is resolved.

Replace transparency in PNG images with white background

It's -alpha off, NOT -alpha remove! iOS app store upload fails when there is an alpha channel in any icon!!

Here's how to do it: mogrify -alpha off *.png

Converting user input string to regular expression

Try using the following function:

const stringToRegex = str => {
    // Main regex
    const main = str.match(/\/(.+)\/.*/)[1]
    
    // Regex options
    const options = str.match(/\/.+\/(.*)/)[1]
    
    // Compiled regex
    return new RegExp(main, options)
}

You can use it like so:

"abc".match(stringToRegex("/a/g"))
//=> ["a"]

Python naming conventions for modules

I know my solution is not very popular from the pythonic point of view, but I prefer to use the Java approach of one module->one class, with the module named as the class. I do understand the reason behind the python style, but I am not too fond of having a very large file containing a lot of classes. I find it difficult to browse, despite folding.

Another reason is version control: having a large file means that your commits tend to concentrate on that file. This can potentially lead to a higher quantity of conflicts to be resolved. You also loose the additional log information that your commit modifies specific files (therefore involving specific classes). Instead you see a modification to the module file, with only the commit comment to understand what modification has been done.

Summing up, if you prefer the python philosophy, go for the suggestions of the other posts. If you instead prefer the java-like philosophy, create a Nib.py containing class Nib.

Blocking device rotation on mobile web pages

New API's are developing (and are currently available)!

screen.orientation.lock();   // webkit only

and

screen.lockOrientation("orientation");

Where "orientation" can be any of the following:

portrait-primary - It represents the orientation of the screen when it is in its primary portrait mode. A screen is considered in its primary portrait mode if the device is held in its normal position and that position is in portrait, or if the normal position of the device is in landscape and the device held turned by 90° clockwise. The normal position is device dependant.

portrait-secondary - It represents the orientation of the screen when it is in its secondary portrait mode. A screen is considered in its secondary portrait mode if the device is held 180° from its normal position and that position is in portrait, or if the normal position of the device is in landscape and the device held is turned by 90° anticlockwise. The normal position is device dependant.

landscape-primary - It represents the orientation of the screen when it is in its primary landscape mode. A screen is considered in its primary landscape mode if the device is held in its normal position and that position is in landscape, or if the normal position of the device is in portrait and the device held is turned by 90° clockwise. The normal position is device dependant.

landscape-secondary - It represents the orientation of the screen when it is in its secondary landscape mode. A screen is considered in its secondary landscape mode if the device held is 180° from its normal position and that position is in landscape, or if the normal position of the device is in portrait and the device held is turned by 90° anticlockwise. The normal position is device dependant.

portrait - It represents both portrait-primary and portrait-secondary.

landscape - It represents both landscape-primary and landscape-secondary.

default - It represents either portrait-primary and landscape-primary depends on natural orientation of devices. For example, if the panel resolution is 1280*800, default will make it landscape, if the resolution is 800*1280, default will make it to portrait.

Mozilla recommends adding a lockOrientationUniversal to screen to make it more cross-browser compatible.

screen.lockOrientationUniversal = screen.lockOrientation || screen.mozLockOrientation || screen.msLockOrientation;

Go here for more info: https://developer.mozilla.org/en-US/docs/Web/API/Screen/lockOrientation

No numeric types to aggregate - change in groupby() behaviour?

I got this error generating a data frame consisting of timestamps and data:

df = pd.DataFrame({'data':value}, index=pd.DatetimeIndex(timestamp))

Adding the suggested solution works for me:

df = pd.DataFrame({'data':value}, index=pd.DatetimeIndex(timestamp), dtype=float))

Thanks Chang She!

Example:

                     data
2005-01-01 00:10:00  7.53
2005-01-01 00:20:00  7.54
2005-01-01 00:30:00  7.62
2005-01-01 00:40:00  7.68
2005-01-01 00:50:00  7.81
2005-01-01 01:00:00  7.95
2005-01-01 01:10:00  7.96
2005-01-01 01:20:00  7.95
2005-01-01 01:30:00  7.98
2005-01-01 01:40:00  8.06
2005-01-01 01:50:00  8.04
2005-01-01 02:00:00  8.06
2005-01-01 02:10:00  8.12
2005-01-01 02:20:00  8.12
2005-01-01 02:30:00  8.25
2005-01-01 02:40:00  8.27
2005-01-01 02:50:00  8.17
2005-01-01 03:00:00  8.21
2005-01-01 03:10:00  8.29
2005-01-01 03:20:00  8.31
2005-01-01 03:30:00  8.25
2005-01-01 03:40:00  8.19
2005-01-01 03:50:00  8.17
2005-01-01 04:00:00  8.18
                     data
2005-01-01 00:00:00  7.636000
2005-01-01 01:00:00  7.990000
2005-01-01 02:00:00  8.165000
2005-01-01 03:00:00  8.236667
2005-01-01 04:00:00  8.180000

PHP, get file name without file extension

@fire incase the filename uses dots, you could get the wrong output. I would use @Gordon method but get the extension too, so the basename function works with all extensions, like this:

$path = "/home/httpd/html/index.php";
$ext = pathinfo($path, PATHINFO_EXTENSION);

$file = basename($path, ".".$ext); // $file is set to "index"

How to copy an object by value, not by reference

Can't you just make a copy constructor? By the way Java always passes references by value, so you keep pointing to the same object.

Ineligible Devices section appeared in Xcode 6.x.x

What worked for me is to install XCode 6.1 (compatible with iOS 8.1)

How to comment and uncomment blocks of code in the Office VBA Editor

With MZ-Tools installed, I comment/uncomment blocks in VBE by using the keyboard shortcut
Ctrl+Alt+C (MZ-Tools default)

ReactJS SyntheticEvent stopPropagation() only works with React events?

Worth noting (from this issue) that if you're attaching events to document, e.stopPropagation() isn't going to help. As a workaround, you can use window.addEventListener() instead of document.addEventListener, then event.stopPropagation() will stop event from propagating to the window.

Set TextView text from html-formatted string resource in XML

I have another case when I have no chance to put CDATA into the xml as I receive the string HTML from a server.

Here is what I get from a server:

<p>The quick brown&nbsp;<br />
fox jumps&nbsp;<br />
 over the lazy dog<br />
</p>

It seems to be more complicated but the solution is much simpler.

private TextView textView;

protected void onCreate(Bundle savedInstanceState) { 
.....
textView = (TextView) findViewById(R.id.text); //need to define in your layout
String htmlFromServer = getHTMLContentFromAServer(); 
textView.setText(Html.fromHtml(htmlFromServer).toString());

}

Hope it helps!
Linh

The smallest difference between 2 Angles

If your two angles are x and y, then one of the angles between them is abs(x - y). The other angle is (2 * PI) - abs(x - y). So the value of the smallest of the 2 angles is:

min((2 * PI) - abs(x - y), abs(x - y))

This gives you the absolute value of the angle, and it assumes the inputs are normalized (ie: within the range [0, 2p)).

If you want to preserve the sign (ie: direction) of the angle and also accept angles outside the range [0, 2p) you can generalize the above. Here's Python code for the generalized version:

PI = math.pi
TAU = 2*PI
def smallestSignedAngleBetween(x, y):
    a = (x - y) % TAU
    b = (y - x) % TAU
    return -a if a < b else b

Note that the % operator does not behave the same in all languages, particularly when negative values are involved, so if porting some sign adjustments may be necessary.

How to get the server path to the web directory in Symfony2 from inside the controller?

My solution is to add this code to the app.php

define('WEB_DIRECTORY', __DIR__);

The problem is that in command line code that uses the constant will break. You can also add the constant to app/console file and the other environment front controllers

Another solution may be add an static method at AppKernel that returns DIR.'/../web/' So you can access everywhere

Unable to read data from the transport connection : An existing connection was forcibly closed by the remote host

The reason this was happening to me was I had a recursive dependency in my DI provider. In my case I had:

services.AddScoped(provider => new CfDbContext(builder.Options));
services.AddScoped(provider => provider.GetService<CfDbContext>());

Fix was to just remove the second scoped service registration

services.AddScoped(provider => new CfDbContext(builder.Options));

Fixing slow initial load for IIS

Options A, B and D seem to be in the same category since they only influence the initial start time, they do warmup of the website like compilation and loading of libraries in memory.

Using C, setting the idle timeout, should be enough so that subsequent requests to the server are served fast (restarting the app pool takes quite some time - in the order of seconds).

As far as I know, the timeout exists to save memory that other websites running in parallel on that machine might need. The price being that one time slow load time.

Besides the fact that the app pool gets shutdown in case of user inactivity, the app pool will also recycle by default every 1740 minutes (29 hours).

From technet:

Internet Information Services (IIS) application pools can be periodically recycled to avoid unstable states that can lead to application crashes, hangs, or memory leaks.

As long as app pool recycling is left on, it should be enough. But if you really want top notch performance for most components, you should also use something like the Application Initialization Module you mentioned.

Get a specific bit from byte

another way of doing it :)

return ((b >> bitNumber) & 1) != 0;

vertical alignment of text element in SVG

The alignment-baseline property is what you're looking for it can take the following values

auto | baseline | before-edge | text-before-edge | 
middle | central | after-edge | text-after-edge | 
ideographic | alphabetic | hanging | mathematical | 
inherit

Description from w3c

This property specifies how an object is aligned with respect to its parent. This property specifies which baseline of this element is to be aligned with the corresponding baseline of the parent. For example, this allows alphabetic baselines in Roman text to stay aligned across font size changes. It defaults to the baseline with the same name as the computed value of the alignment-baseline property. That is, the position of "ideographic" alignment-point in the block-progression-direction is the position of the "ideographic" baseline in the baseline-table of the object being aligned.

W3C Source

Unfortunately, although this is the "correct" way of achieving what you're after it would appear Firefox have not implemented a lot of the presentation attributes for the SVG Text Module ('SVG in Firefox' MDN Documentation)

TextFX menu is missing in Notepad++

It should usually work using the method Dave described in his answer. (I can confirm seeing "TextFX Characters" in the Available tab in Plugin Manager.)

If it does not, you can try downloading the zip file from here and put its contents (it's one file called NppTextFX.dll) inside the plugins folder where Notepad++ is installed. I suggest doing this while Notepad++ itself is not running.

Unprotect workbook without password

No longer works for spreadsheets Protected with Excel 2013 or later -- they improved the pw hash. So now need to unzip .xlsx and hack the internals.

Understanding offsetWidth, clientWidth, scrollWidth and -Height, respectively

The CSS box model is rather complicated, particularly when it comes to scrolling content. While the browser uses the values from your CSS to draw boxes, determining all the dimensions using JS is not straight-forward if you only have the CSS.

That's why each element has six DOM properties for your convenience: offsetWidth, offsetHeight, clientWidth, clientHeight, scrollWidth and scrollHeight. These are read-only attributes representing the current visual layout, and all of them are integers (thus possibly subject to rounding errors).

Let's go through them in detail:

  • offsetWidth, offsetHeight: The size of the visual box incuding all borders. Can be calculated by adding width/height and paddings and borders, if the element has display: block
  • clientWidth, clientHeight: The visual portion of the box content, not including borders or scroll bars , but includes padding . Can not be calculated directly from CSS, depends on the system's scroll bar size.
  • scrollWidth, scrollHeight: The size of all of the box's content, including the parts that are currently hidden outside the scrolling area. Can not be calculated directly from CSS, depends on the content.

CSS2 Box Model

Try it out: jsFiddle


Since offsetWidth takes the scroll bar width into account, we can use it to calculate the scroll bar width via the formula

scrollbarWidth = offsetWidth - clientWidth - getComputedStyle().borderLeftWidth - getComputedStyle().borderRightWidth

Unfortunately, we may get rounding errors, since offsetWidth and clientWidth are always integers, while the actual sizes may be fractional with zoom levels other than 1.

Note that this

scrollbarWidth = getComputedStyle().width + getComputedStyle().paddingLeft + getComputedStyle().paddingRight - clientWidth

does not work reliably in Chrome, since Chrome returns width with scrollbar already substracted. (Also, Chrome renders paddingBottom to the bottom of the scroll content, while other browsers don't)

Access to the requested object is only available from the local network phpmyadmin

On Xampp 5.6.3 Windows Path C:\xampp\apache\conf\extra\httpd-xampp.conf comment in this: #Require local

New XAMPP security concept ... #Require local ...

Initialize a string in C to empty string

calloc allocates the requested memory and returns a pointer to it. It also sets allocated memory to zero.

In case you are planning to use your string as empty string all the time:

char *string = NULL;
string = (char*)calloc(1, sizeof(char));

In case you are planning to store some value in your string later:

char *string = NULL;
int numberOfChars = 50; // you can use as many as you need
string = (char*)calloc(numberOfChars + 1, sizeof(char));

Making text background transparent but not text itself

opacity will make both text and background transparent. Use a semi-transparent background-color instead, by using a rgba() value for example. Works on IE8+

System.currentTimeMillis vs System.nanoTime

Yes, if such precision is required use System.nanoTime(), but be aware that you are then requiring a Java 5+ JVM.

On my XP systems, I see system time reported to at least 100 microseconds 278 nanoseconds using the following code:

private void test() {
    System.out.println("currentTimeMillis: "+System.currentTimeMillis());
    System.out.println("nanoTime         : "+System.nanoTime());
    System.out.println();

    testNano(false);                                                            // to sync with currentTimeMillis() timer tick
    for(int xa=0; xa<10; xa++) {
        testNano(true);
        }
    }

private void testNano(boolean shw) {
    long strMS=System.currentTimeMillis();
    long strNS=System.nanoTime();
    long curMS;
    while((curMS=System.currentTimeMillis()) == strMS) {
        if(shw) { System.out.println("Nano: "+(System.nanoTime()-strNS)); }
        }
    if(shw) { System.out.println("Nano: "+(System.nanoTime()-strNS)+", Milli: "+(curMS-strMS)); }
    }

Accessing dictionary value by index in python

Let us take an example of dictionary:

numbers = {'first':0, 'second':1, 'third':3}

When I did

numbers.values()[index]

I got an error:'dict_values' object does not support indexing

When I did

numbers.itervalues()

to iterate and extract the values it is also giving an error:'dict' object has no attribute 'iteritems'

Hence I came up with new way of accessing dictionary elements by index just by converting them to tuples.

tuple(numbers.items())[key_index][value_index]

for example:

tuple(numbers.items())[0][0] gives 'first'

if u want to edit the values or sort the values the tuple object does not allow the item assignment. In this case you can use

list(list(numbers.items())[index])

Parsing JSON string in Java

you have an extra "}" in each object, you may write the json string like this:

public class ShowActivity {   
    private final static String  jString = "{" 
    + "    \"geodata\": [" 
    + "        {" 
    + "                \"id\": \"1\"," 
    + "                \"name\": \"Julie Sherman\","                  
    + "                \"gender\" : \"female\"," 
    + "                \"latitude\" : \"37.33774833333334\"," 
    + "                \"longitude\" : \"-121.88670166666667\""            
    + "                }" 
    + "        }," 
    + "        {" 
    + "                \"id\": \"2\"," 
    + "                \"name\": \"Johnny Depp\","          
    + "                \"gender\" : \"male\"," 
    + "                \"latitude\" : \"37.336453\"," 
    + "                \"longitude\" : \"-121.884985\""            
    + "                }" 
    + "        }" 
    + "    ]" 
    + "}"; 
}

How to align footer (div) to the bottom of the page?

I am a newbie and these methods are not working for me. However, I tried a margin-top property in css and simply added the value of content pixels +5.

Example: my content layout had a height of 1000px so I put a margin-top value of 1005px in the footer css which gave me a 5px border and a footer that sits delightfully at the bottom of my site.

Probably an amateur way of doing it, but EFFECTIVE!!!

Run a string as a command within a Bash script

Here is my gradle build script that executes strings stored in heredocs:

current_directory=$( realpath "." )
GENERATED=${current_directory}/"GENERATED"
build_gradle=$( realpath build.gradle )

## touch because .gitignore ignores this folder:
touch $GENERATED

COPY_BUILD_FILE=$( cat <<COPY_BUILD_FILE_HEREDOC

    cp 
        $build_gradle 
        $GENERATED/build.gradle

COPY_BUILD_FILE_HEREDOC
)
$COPY_BUILD_FILE

GRADLE_COMMAND=$( cat <<GRADLE_COMMAND_HEREDOC

    gradle run

        --build-file       
            $GENERATED/build.gradle

        --gradle-user-home 
            $GENERATED  

        --no-daemon

GRADLE_COMMAND_HEREDOC
)
$GRADLE_COMMAND

The lone ")" are kind of ugly. But I have no clue how to fix that asthetic aspect.

How do I send a file as an email attachment using Linux command line?

metamail has the tool metasend

metasend -f mysqlbackup.sql.gz -t [email protected] -s Backup -m application/x-gzip -b

How to switch back to 'master' with git?

For deleting the branch you have to stash the changes made on the branch or you need to commit the changes you made on the branch. Follow the below steps if you made any changes in the current branch.

  1. git stash or git commit -m "XXX"
  2. git checkout master
  3. git branch -D merchantApi

Note: Above steps will delete the branch locally.

Static Initialization Blocks

There are a few actual reasons that it is required to exist:

  1. initializing static final members whose initialization might throw an exception
  2. initializing static final members with calculated values

People tend to use static {} blocks as a convenient way to initialize things that the class depends on within the runtime as well - such as ensuring that particular class is loaded (e.g., JDBC drivers). That can be done in other ways; however, the two things that I mention above can only be done with a construct like the static {} block.

Interface extends another interface but implements its methods

Why does it implement its methods? How can it implement its methods when an interface can't contain method body? How can it implement the methods when it extends the other interface and not implement it? What is the purpose of an interface implementing another interface?

Interface does not implement the methods of another interface but just extends them. One example where the interface extension is needed is: consider that you have a vehicle interface with two methods moveForward and moveBack but also you need to incorporate the Aircraft which is a vehicle but with some addition methods like moveUp, moveDown so in the end you have:

public interface IVehicle {
  bool moveForward(int x);
  bool moveBack(int x);
};

and airplane:

public interface IAirplane extends IVehicle {
  bool moveDown(int x);
  bool moveUp(int x);
};

What is the Simplest Way to Reverse an ArrayList?

ArrayList<Integer> myArray = new ArrayList<Integer>();

myArray.add(1);
myArray.add(2);
myArray.add(3);

int reverseArrayCounter = myArray.size() - 1;

for (int i = reverseArrayCounter; i >= 0; i--) {
    System.out.println(myArray.get(i));
}

How can I run a PHP script in the background after a form is submitted?

And why not making a HTTP Request on the script and ignoring the response ?

http://php.net/manual/en/function.httprequest-send.php

If you make your request on the script you need to call your webserver will run it in background and you can (in your main script) show a message telling the user that the script is running.

How to check if an app is installed from a web-page on an iPhone?

iOS Safari has a feature that allows you to add a "smart" banner to your webpage that will link either to your app, if it is installed, or to the App Store.

You do this by adding a meta tag to the page. You can even specify a detailed app URL if you want the app to do something special when it loads.

Details are at Apple's Promoting Apps with Smart App Banners page.

The mechanism has the advantages of being easy and presenting a standardized banner. The downside is that you don't have much control over the look or location. Also, all bets are off if the page is viewed in a browser other than Safari.

querySelector and querySelectorAll vs getElementsByClassName and getElementById in JavaScript

The main difference between querySelector and getlementbyID(Claassname,Tagname etc) is if there is more than one elements which satifies the condition querySelector will return only one output whereas getElementBy* will return all the elements.

Lets consider an example to make it more clear.

 <nav id="primary" class="menu">
                            <a class="link" href="#">For Business</a>
                            <a class="link" href="#">Become an Instructor</a>
                            <a class="link" href="#">Mobile Applications</a>
                            <a class="link" href="#">Support</a>
                            <a class="link" href="#">Help</a>
   </nav> 

Below code will explain the difference

**QUERY SELECTOR**
document.querySelector('.link'); // Output : For Business (element)

document.querySelectorAll('.link'); //Out All the element with class link

**GET ELEMENT**
document.getElementsByClassName('link') // Output : will return all the element with a class "link" but whereas in query selector it will return only one element which encounters first.

Inshort if we want to select single element go for queryslector or if we want multiple element go for getElement

Sending HTML Code Through JSON

Just to expand on @T.J. Crowder's answer.

json_encode does well with simple html strings, in my experience however json_encode often becomes confused by, (or it becomes quite difficult to properly escape) longer complex nested html mixed with php. Two options to consider if you are in this position are: encoding/decoding the markup first with something like [base64_encode][1]/ decode (quite a bit of a performance hit), or (and perhaps preferably) be more selective in what you are passing via json, and generate the necessary markup on the client side instead.

Changing an AIX password via script?

In addition to the other suggestions, you can also achieve this using a HEREDOC.

In your immediate case, this might look like:

$ /usr/bin/passwd root <<EOF
test
test
EOF

How to customize the configuration file of the official PostgreSQL Docker image?

My solution is for colleagues who needs to make changes in config before launching docker-entrypoint-initdb.d

I was needed to change 'shared_preload_libraries' setting so during it's work postgres already has new library preloaded and code in docker-entrypoint-initdb.d can use it.

So I just patched postgresql.conf.sample file in Dockerfile:

RUN echo "shared_preload_libraries='citus,pg_cron'" >> /usr/share/postgresql/postgresql.conf.sample
RUN echo "cron.database_name='newbie'" >> /usr/share/postgresql/postgresql.conf.sample

And with this patch it become possible to add extension in .sql file in docker-entrypoint-initdb.d/:

CREATE EXTENSION pg_cron;

How to get every first element in 2 dimensional list

You could use this:

a = ((4.0, 4, 4.0), (3.0, 3, 3.6), (3.5, 6, 4.8))
a = np.array(a)
a[:,0]
returns >>> array([4. , 3. , 3.5])

How to create a numeric vector of zero length in R

Simply:

x <- vector(mode="numeric", length=0)

How to get label text value form a html page?

This will get what you want in plain JS.

var el = document.getElementById('*spaM4');
text = (el.innerText || el.textContent);

FIDDLE

WCF timeout exception detailed investigation

Looks like this exception message is quite generic and can be received due to a variety of reasons. We ran into this while deploying the client on Windows 8.1 machines. Our WCF client runs inside of a windows service and continuously polls the WCF service. The windows service runs under a non-admin user. The issue was fixed by setting the clientCredentialType to "Windows" in the WCF configuration to allow the authentication to pass-through, as in the following:

      <security mode="None">
        <transport clientCredentialType="Windows" proxyCredentialType="None"
          realm="" />
        <message clientCredentialType="UserName" algorithmSuite="Default" />
      </security>

Using Mysql WHERE IN clause in codeigniter

$data = $this->db->get_where('columnname',array('code' => 'B'));
$this->db->where_in('columnname',$data);
$this->db->where('code !=','B');
$query =  $this->db->get();
return $query->result_array();

How to set specific Java version to Maven

Adding my two cents and explicitly providing the solution.

I have two JDKs installed on my Windows Machine - JDK 1.5 and JDK 1.6.

My default (and set to windows system environment variable) JAVA_HOME is set to JDK 1.5.

However, I have a maven project that I need to build (i.e., JBehave Tutorial's Etsy.com) using JDK 1.6.

My solution in this scenario (which worked!), is as suggested by @DanielBarbarian to set it in mvn.bat.

For some not familiar with window's batch file, I just basically added the set JAVA_HOME=<path_to_other_jdk> line after @REM ==== START VALIDATION ==== in mvn.bat (i.e., %MAVEN_HOME%\bin\mvn.bat):

@REM ==== START VALIDATION ====
set JAVA_HOME=C:\Program Files\Java\jdk1.6.0_45\jre
if not "%JAVA_HOME%" == "" goto OkJHome

Where does error CS0433 "Type 'X' already exists in both A.dll and B.dll " come from?

Shut down w3svc and delete everything from c:\Windows\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\root\

added

  • on Windows 7

    c:\Users\{username}\AppData\Local\Temp\Temporary ASP.NET Files\root\

  • on IIS servers (64 bit) this can also occur. Look for:

    C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Temporary ASP.NET Files\root

    (replace v4.0.30319 by the framework version you're using if newer on your server)

Click event on select option element in chrome

I've had simmilar issue. change event was not good for me because i've needed to refresh some data when user clicks on option. After few trials i've got this solution:

$('select').on('click',function(ev){
    if(ev.offsetY < 0){
      //user click on option  
    }else{
      //dropdown is shown
    }
});

I agree that this is very ugly and you should stick with change event where you can, but this solved my problem.

Update TextView Every Second

This Code work for me..

//Get Time and Date
private String getTimeMethod(String formate)
{
    Date date = new Date();
    SimpleDateFormat dateFormat = new SimpleDateFormat(formate);
    String formattedDate= dateFormat.format(date);
    return formattedDate;
}

//this method is used to refresh Time every Second
private void refreshTime() //Call this method to refresh time
{
    new Timer().schedule(new TimerTask() {
        @Override
        public void run() {
            runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    txtV_Time.setText(getTimeMethod("hh:mm:ss a")); //hours,Min and Second with am/pm
                    txtV_Date.setText(getTimeMethod("dd-MMM-yy")); //You have to pass your DateFormate in getTimeMethod()          
                };
            });
        }
    }, 0, 1000);//1000 is a Refreshing Time (1second)
}

Python: Maximum recursion depth exceeded

You can increment the stack depth allowed - with this, deeper recursive calls will be possible, like this:

import sys
sys.setrecursionlimit(10000) # 10000 is an example, try with different values

... But I'd advise you to first try to optimize your code, for instance, using iteration instead of recursion.

How to initialize an array's length in JavaScript?

[...Array(6)].map(x => 0);
// [0, 0, 0, 0, 0, 0]

OR

Array(6).fill(0);
// [0, 0, 0, 0, 0, 0]

Note: you can't loop empty slots i.e. Array(4).forEach(() => …)


OR

( typescript safe )

Array(6).fill(null).map((_, i) => i);
// [0, 1, 2, 3, 4, 5]

OR

Classic method using a function ( works in any browser )

function NewArray(size) {
    var x = [];
    for (var i = 0; i < size; ++i) {
        x[i] = i;
    }
    return x;
}

var a = NewArray(10);
// [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

Creating nested arrays

When creating a 2D array with the fill intuitively should create new instances. But what actually going to happen is the same array will be stored as a reference.

var a = Array(3).fill([6]);
// [  [6], [6], [6]  ]

a[0].push(9);
// [  [6, 9], [6, 9], [6, 9]  ]

Solution

var a = [...Array(3)].map(x => []);

a[0].push(4, 2);
// [  [4, 2], [], []  ]

So a 3x2 Array will look something like this:

[...Array(3)].map(x => Array(2).fill(0));
// [  [0, 0], [0, 0], [0, 0]  ]

N-dimensional array

function NArray(...dimensions) {
    var index = 0;
    function NArrayRec(dims) {
        var first = dims[0], next = dims.slice().splice(1); 
        if(dims.length > 1) 
            return Array(dims[0]).fill(null).map((x, i) => NArrayRec(next ));
        return Array(dims[0]).fill(null).map((x, i) => (index++));
    }
    return NArrayRec(dimensions);
}

var arr = NArray(3, 2, 4);
// [   [  [ 0,  1,  2,  3 ] , [  4,  5,  6,  7]  ],
//     [  [ 8,  9,  10, 11] , [ 12, 13, 14, 15]  ],
//     [  [ 16, 17, 18, 19] , [ 20, 21, 22, 23]  ]   ]

Initialize a chessboard

var Chessboard = [...Array(8)].map((x, j) => {
    return Array(8).fill(null).map((y, i) => {
        return `${String.fromCharCode(65 + i)}${8 - j}`;
    });
});

// [ [A8, B8, C8, D8, E8, F8, G8, H8],
//   [A7, B7, C7, D7, E7, F7, G7, H7],
//   [A6, B6, C6, D6, E6, F6, G6, H6],
//   [A5, B5, C5, D5, E5, F5, G5, H5],
//   [A4, B4, C4, D4, E4, F4, G4, H4],
//   [A3, B3, C3, D3, E3, F3, G3, H3],
//   [A2, B2, C2, D2, E2, F2, G2, H2],
//   [A1, B1, C1, D1, E1, F1, G1, H1] ]

Math filled values

handy little method overload when working with math


function NewArray( size , method, linear )
{
    method = method || ( i => i ); 
    linear = linear || false;
    var x = [];
    for( var i = 0; i < size; ++i )
        x[ i ] = method( linear ? i / (size-1) : i );
    return x;
}

NewArray( 4 ); 
// [ 0, 1, 2, 3 ]

NewArray( 4, Math.sin ); 
// [ 0, 0.841, 0.909, 0.141 ]

NewArray( 4, Math.sin, true );
// [ 0, 0.327, 0.618, 0.841 ]

var pow2 = ( x ) => x * x;

NewArray( 4, pow2 ); 
// [ 0, 1, 4, 9 ]

NewArray( 4, pow2, true ); 
// [ 0, 0.111, 0.444, 1 ]

What is the significance of load factor in HashMap?

The documentation explains it pretty well:

An instance of HashMap has two parameters that affect its performance: initial capacity and load factor. The capacity is the number of buckets in the hash table, and the initial capacity is simply the capacity at the time the hash table is created. The load factor is a measure of how full the hash table is allowed to get before its capacity is automatically increased. When the number of entries in the hash table exceeds the product of the load factor and the current capacity, the hash table is rehashed (that is, internal data structures are rebuilt) so that the hash table has approximately twice the number of buckets.

As a general rule, the default load factor (.75) offers a good tradeoff between time and space costs. Higher values decrease the space overhead but increase the lookup cost (reflected in most of the operations of the HashMap class, including get and put). The expected number of entries in the map and its load factor should be taken into account when setting its initial capacity, so as to minimize the number of rehash operations. If the initial capacity is greater than the maximum number of entries divided by the load factor, no rehash operations will ever occur.

As with all performance optimizations, it is a good idea to avoid optimizing things prematurely (i.e. without hard data on where the bottlenecks are).

Bootstrap 3: How to get two form inputs on one line and other inputs on individual lines?

I resorted to creating 2 style cascades using inline-block for input that pretty much override the field:

.input-sm {
    height: 2.1em;
    display: inline-block;
}

and a series of fixed sizes as opposed to %

.input-10 {
    width: 10em;
}

.input-32 {
    width: 32em;
}

Two statements next to curly brace in an equation

Or this:

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

HTML Display Current date

This helped me:

<p>Date/Time: <span id="datetime"></span></p><script>var dt = new Date();
document.getElementById("datetime").innerHTML=dt.toLocaleString();</script>    

Removing all script tags from html with JS Regular Expression

Try this:

var text = text.replace(/<script[^>]*>(?:(?!<\/script>)[^])*<\/script>/g, "")

How to store an array into mysql?

You can always serialize the array and store that in the database.
PHP Serialize

You can then unserialize the array when needed.

Freeze screen in chrome debugger / DevTools panel for popover inspection?

Got it working. Here was my procedure:

  1. Browse to the desired page
  2. Open the dev console - F12 on Windows/Linux or option + ? + J on macOS
  3. Select the Sources tab in chrome inspector
  4. In the web browser window, hover over the desired element to initiate the popover
  5. Hit F8 on Windows/Linux (or fn + F8 on macOS) while the popover is showing. If you have clicked anywhere on the actual page F8 will do nothing. Your last click needs to be somewhere in the inspector, like the sources tab
  6. Go to the Elements tab in inspector
  7. Find your popover (it will be nested in the trigger element's HTML)
  8. Have fun modifying the CSS

mailto link multiple body lines

You can use URL encoding to encode the newline as %0A.

mailto:[email protected]?subject=test&body=type%20your%0Amessage%20here

While the above appears to work in many cases, user olibre points out that the RFC governing the mailto URI scheme specifies that %0D%0A (carriage return + line feed) should be used instead of %0A (line feed). See also: Newline Representations.

How to specify table's height such that a vertical scroll bar appears?

to set the height of table, you need to first set css property "display: block" then you can add "width/height" properties. I find this Mozilla Article a very good resource to learn how to style tables : Link

Passing variables in remote ssh command

The list of accepted environment variables on SSHD by default includes LC_*. Thus:

LC_MY_BUILDN="1.2.3" ssh -o "SendEnv LC_MY_BUILDN" ssh-host 'echo $LC_MY_BUILDN'
1.2.3

What is System, out, println in System.out.println() in Java

System is a final class from the java.lang package.

out is a class variable of type PrintStream declared in the System class.

println is a method of the PrintStream class.

BehaviorSubject vs Observable?

Observable and subject both are observable's means an observer can track them. but both of them have some unique characteristics. Further there are total 3 type of subjects each of them again have unique characteristics. lets try to to understand each of them.

you can find the practical example here on stackblitz. (You need to check the console to see the actual output)

enter image description here

Observables

They are cold: Code gets executed when they have at least a single observer.

Creates copy of data: Observable creates copy of data for each observer.

Uni-directional: Observer can not assign value to observable(origin/master).

Subject

They are hot: code gets executed and value gets broadcast even if there is no observer.

Shares data: Same data get shared between all observers.

bi-directional: Observer can assign value to observable(origin/master).

If are using using subject then you miss all the values that are broadcast before creation of observer. So here comes Replay Subject

ReplaySubject

They are hot: code gets executed and value get broadcast even if there is no observer.

Shares data: Same data get shared between all observers.

bi-directional: Observer can assign value to observable(origin/master). plus

Replay the message stream: No matter when you subscribe the replay subject you will receive all the broadcasted messages.

In subject and replay subject you can not set the initial value to observable. So here comes Behavioral Subject

BehaviorSubject

They are hot: code gets executed and value get broadcast even if there is no observer.

Shares data: Same data get shared between all observers.

bi-directional: Observer can assign value to observable(origin/master). plus

Replay the message stream: No matter when you subscribe the replay subject you will receive all the broadcasted messages.

You can set initial value: You can initialize the observable with default value.

How to get the index of an element in an IEnumerable?

The way I'm currently doing this is a bit shorter than those already suggested and as far as I can tell gives the desired result:

 var index = haystack.ToList().IndexOf(needle);

It's a bit clunky, but it does the job and is fairly concise.

How can I render a list select box (dropdown) with bootstrap?

Another option could be using bootstrap select. On their own words:

A custom select / multiselect for Bootstrap using button dropdown, designed to behave like regular Bootstrap selects.

here-document gives 'unexpected end of file' error

Along with the other answers mentioned by Barmar and Joni, I've noticed that I sometimes have to leave a blank line before and after my EOF when using <<-EOF.

In CSS how do you change font size of h1 and h2

What have you tried? This should work.

h1 { font-size: 20pt; }
h2 { font-size: 16pt; }

How to pass data in the ajax DELETE request other than headers

Read this Bug Issue: http://bugs.jquery.com/ticket/11586

Quoting the RFC 2616 Fielding

The DELETE method requests that the origin server delete the resource identified by the Request-URI.

So you need to pass the data in the URI

$.ajax({
    url: urlCall + '?' + $.param({"Id": Id, "bolDeleteReq" : bolDeleteReq}),
    type: 'DELETE',
    success: callback || $.noop,
    error: errorCallback || $.noop
});

Merge unequal dataframes and replace missing rows with 0

Or, as an alternative to @Chase's code, being a recent plyr fan with a background in databases:

require(plyr)
zz<-join(df1, df2, type="left")
zz[is.na(zz)] <- 0

Get ID of element that called a function

Pass a reference to the element into the function when it is called:

<area id="nose" onmouseover="zoom(this);" />

<script>
  function zoom(ele) {
    var id = ele.id;

    console.log('area element id = ' + id);
  }
</script>

How to create multiple page app using react

Preface

This answer uses the dynamic routing approach embraced in react-router v4+. Other answers may reference the previously-used "static routing" approach that has been abandoned by react-router.

Solution

react-router is a great solution. You create your pages as Components and the router swaps out the pages according to the current URL. In other words, it replaces your original page with your new page dynamically instead of asking the server for a new page.

For web apps I recommend you read these two things first:

Summary of the general approach:

1 - Add react-router-dom to your project:

Yarn

yarn add react-router-dom

or NPM

npm install react-router-dom

2 - Update your index.js file to something like:

import { BrowserRouter } from 'react-router-dom';

ReactDOM.render((
  <BrowserRouter>
    <App /> {/* The various pages will be displayed by the `Main` component. */}
  </BrowserRouter>
  ), document.getElementById('root')
);

3 - Create a Main component that will show your pages according to the current URL:

import React from 'react';
import { Switch, Route } from 'react-router-dom';

import Home from '../pages/Home';
import Signup from '../pages/Signup';

const Main = () => {
  return (
    <Switch> {/* The Switch decides which component to show based on the current URL.*/}
      <Route exact path='/' component={Home}></Route>
      <Route exact path='/signup' component={Signup}></Route>
    </Switch>
  );
}

export default Main;

4 - Add the Main component inside of the App.js file:

function App() {
  return (
    <div className="App">
      <Navbar />
      <Main />
    </div>
  );
}

5 - Add Links to your pages.

(You must use Link from react-router-dom instead of just a plain old <a> in order for the router to work properly.)

import { Link } from "react-router-dom";
...
<Link to="/signup">
  <button variant="outlined">
    Sign up
  </button>
</Link>

Pandas aggregate count distinct

Just adding to the answers already given, the solution using the string "nunique" seems much faster, tested here on ~21M rows dataframe, then grouped to ~2M

%time _=g.agg({"id": lambda x: x.nunique()})
CPU times: user 3min 3s, sys: 2.94 s, total: 3min 6s
Wall time: 3min 20s

%time _=g.agg({"id": pd.Series.nunique})
CPU times: user 3min 2s, sys: 2.44 s, total: 3min 4s
Wall time: 3min 18s

%time _=g.agg({"id": "nunique"})
CPU times: user 14 s, sys: 4.76 s, total: 18.8 s
Wall time: 24.4 s

Chrome - ERR_CACHE_MISS

Yes, this is a current issue in Chrome. There is an issue report here.

The fix will appear in 40.x.y.z versions.

Until then? I don't think you can resolve the issue yourself. But you can ignore it. The shown error is only related to the dev tools and does not influence the behavior of your website. If you have any other problems they are not related to this error.

Why are unnamed namespaces used and what are their benefits?

Unnamed namespaces are a utility to make an identifier translation unit local. They behave as if you would choose a unique name per translation unit for a namespace:

namespace unique { /* empty */ }
using namespace unique;
namespace unique { /* namespace body. stuff in here */ }

The extra step using the empty body is important, so you can already refer within the namespace body to identifiers like ::name that are defined in that namespace, since the using directive already took place.

This means you can have free functions called (for example) help that can exist in multiple translation units, and they won't clash at link time. The effect is almost identical to using the static keyword used in C which you can put in in the declaration of identifiers. Unnamed namespaces are a superior alternative, being able to even make a type translation unit local.

namespace { int a1; }
static int a2;

Both a's are translation unit local and won't clash at link time. But the difference is that the a1 in the anonymous namespace gets a unique name.

Read the excellent article at comeau-computing Why is an unnamed namespace used instead of static? (Archive.org mirror).

Multiplication on command line terminal

Internal Methods

Bash supports arithmetic expansion with $(( expression )). For example:

$ echo $(( 5 * 5 ))
25

External Methods

A number of utilities provide arithmetic, including bc and expr.

$ echo '5 * 5' | /usr/bin/bc
25

$ /usr/bin/expr 5 \* 5
25

How can I get the CheckBoxList selected values, what I have doesn't seem to work C#.NET/VisualWebPart

An elegant way to implement this would be to make an extension method, like this:

public static class Extensions
{
    public static List<string> GetSelectedItems(this CheckBoxList cbl)
    {
        var result = new List<string>();

        foreach (ListItem item in cbl.Items)
            if (item.Selected)
                result.Add(item.Value);

        return result;
    }
}

I can then use something like this to compose a string will all values separated by ';':

string.Join(";", cbl.GetSelectedItems());

MySQL: how to get the difference between two timestamps in seconds

How about "TIMESTAMPDIFF":

SELECT TIMESTAMPDIFF(SECOND,'2009-05-18','2009-07-29') from `post_statistics`

https://dev.mysql.com/doc/refman/5.7/en/date-and-time-functions.html#function_timestampdiff

Get the Selected value from the Drop down box in PHP

Posting it from my project.

<select name="parent" id="parent"><option value="0">None</option>
<?php
 $select="select=selected";
 $allparent=mysql_query("select * from tbl_page_content where parent='0'");
 while($parent=mysql_fetch_array($allparent))
   {?>
   <option value="<?= $parent['id']; ?>" <?php if( $pageDetail['parent']==$parent['id'] ) { echo($select); }?>><?= $parent['name']; ?></option>
  <?php 
   }
  ?></select>

How to change the plot line color from blue to black?

If you get the object after creation (for instance after "seasonal_decompose"), you can always access and edit the properties of the plot; for instance, changing the color of the first subplot from blue to black:

plt.axes[0].get_lines()[0].set_color('black')

HTML for the Pause symbol in audio and video control

I'm using ▐ ▌

HTML: &#9616;&nbsp;&#9612;

CSS: \2590\A0\258C

Reverse Contents in Array

Both answers look correct to me.

  1. The first arr[i] = temp; should be removed

  2. You should do a second loop to print all elements, not just half the array. The loop that does the reverse doesn't need to print it.

ORA-00904: invalid identifier

FYI, in this case the cause was found to be mixed case column name in the DDL for table creation.

However, if you are mixing "old style" and ANSI joins you could get the same error message even when the DDL was done properly with uppercase table name. This happened to me, and google sent me to this stackoverflow page so I thought I'd share since I was here.

--NO PROBLEM: ANSI syntax
SELECT A.EMPLID, B.FIRST_NAME, C.LAST_NAME
FROM PS_PERSON A
INNER JOIN PS_NAME_PWD_VW B ON B.EMPLID = A.EMPLID
INNER JOIN PS_HCR_PERSON_NM_I C ON C.EMPLID = A.EMPLID
WHERE 
    LENGTH(A.EMPLID) = 9
    AND LENGTH(B.LAST_NAME) > 5
    AND LENGTH(C.LAST_NAME) > 5
ORDER BY 1, 2, 3
/

--NO PROBLEM: OLD STYLE/deprecated/traditional oracle proprietary join syntax
SELECT A.EMPLID, B.FIRST_NAME, C.LAST_NAME
FROM PS_PERSON A
, PS_NAME_PWD_VW B 
, PS_HCR_PERSON_NM_I C 
WHERE 
    B.EMPLID = A.EMPLID
    and C.EMPLID = A.EMPLID
    and LENGTH(A.EMPLID) = 9
    AND LENGTH(B.LAST_NAME) > 5
    AND LENGTH(C.LAST_NAME) > 5
ORDER BY 1, 2, 3
/

The two SQL statements above are equivalent and produce no error.

When you try to mix them you can get lucky, or you can get an Oracle has a ORA-00904 error.

--LUCKY: mixed syntax (ANSI joins appear before OLD STYLE)
SELECT A.EMPLID, B.FIRST_NAME, C.LAST_NAME
FROM 
    PS_PERSON A
    inner join PS_HCR_PERSON_NM_I C on C.EMPLID = A.EMPLID
    , PS_NAME_PWD_VW B
WHERE 
    B.EMPLID = A.EMPLID
    and LENGTH(A.EMPLID) = 9
    AND LENGTH(B.FIRST_NAME) > 5
    AND LENGTH(C.LAST_NAME) > 5
/

--PROBLEM: mixed syntax (OLD STYLE joins appear before ANSI)
--http://sqlfascination.com/2013/08/17/oracle-ansi-vs-old-style-joins/
SELECT A.EMPLID, B.FIRST_NAME, C.LAST_NAME
FROM 
    PS_PERSON A
    , PS_NAME_PWD_VW B
    inner join PS_HCR_PERSON_NM_I C on C.EMPLID = A.EMPLID
WHERE 
    B.EMPLID = A.EMPLID
    and LENGTH(A.EMPLID) = 9
    AND LENGTH(B.FIRST_NAME) > 5
    AND LENGTH(C.LAST_NAME) > 5
/

And the unhelpful error message that doesn't really describe the problem at all:

>[Error] Script lines: 1-12 -------------------------
ORA-00904: "A"."EMPLID": invalid identifier  Script line 6, statement line 6,
column 51 

I was able to find some research on this in the following blog post:

In my case, I was attempting to manually convert from old style to ANSI style joins, and was doing so incrementally, one table at a time. This appears to have been a bad idea. Instead, it's probably better to convert all tables at once, or comment out a table and its where conditions in the original query in order to compare with the new ANSI query you are writing.

Send push to Android by C# using FCM (Firebase Cloud Messaging)

Try to send a json object. Replace this:

tRequest.ContentType = " application/x-www-form-urlencoded;charset=UTF-8";    
string postData = "collapse_key=score_update&time_to_live=108&delay_while_idle=1&data.message=" + value + "&data.time=" + System.DateTime.Now.ToString() + "&registration_id=" + deviceId + "";
        Console.WriteLine(postData);
        Byte[] byteArray = Encoding.UTF8.GetBytes(postData);

For this:

tRequest.ContentType = "application/json"; 
    var data = new
        {
            to = deviceId,
            notification = new
            {
                body = "This is the message",
                title = "This is the title",
                icon = "myicon"
            }
        };

        var serializer = new JavaScriptSerializer();
        var json = serializer.Serialize(data);

        Byte[] byteArray = Encoding.UTF8.GetBytes(json);

Using Eloquent ORM in Laravel to perform search of database using LIKE

Use double quotes instead of single quote eg :

where('customer.name', 'LIKE', "%$findcustomer%")

Below is my code:

public function searchCustomer($findcustomer)
{
    $customer = DB::table('customer')
                  ->where('customer.name', 'LIKE', "%$findcustomer%")
                  ->orWhere('customer.phone', 'LIKE', "%$findcustomer%")
                  ->get();

    return View::make("your view here");
}

Linear regression with matplotlib / numpy

This code:

from scipy.stats import linregress

linregress(x,y) #x and y are arrays or lists.

gives out a list with the following:

slope : float
slope of the regression line
intercept : float
intercept of the regression line
r-value : float
correlation coefficient
p-value : float
two-sided p-value for a hypothesis test whose null hypothesis is that the slope is zero
stderr : float
Standard error of the estimate

Source

forEach() in React JSX does not output any HTML

You need to pass an array of element to jsx. The problem is that forEach does not return anything (i.e it returns undefined). So it's better to use map because map returns an array:

class QuestionSet extends Component {
render(){ 
    <div className="container">
       <h1>{this.props.question.text}</h1>
       {this.props.question.answers.map((answer, i) => {     
           console.log("Entered");                 
           // Return the element. Also pass key     
           return (<Answer key={answer} answer={answer} />) 
        })}
}

export default QuestionSet;

The static keyword and its various uses in C++

I'm not a C programmer so I can't give you information on the uses of static in a C program properly, but when it comes to Object Oriented programming static basically declares a variable, or a function or a class to be the same throughout the life of the program. Take for example.

class A
{
public:
    A();
    ~A();
    void somePublicMethod();
private:
    void somePrivateMethod();
};

When you instantiate this class in your Main you do something like this.

int main()
{
   A a1;
   //do something on a1
   A a2;
   //do something on a2
}

These two class instances are completely different from each other and operate independently from one another. But if you were to recreate the class A like this.

class A
{
public:
    A();
    ~A();
    void somePublicMethod();
    static int x;
private:
    void somePrivateMethod();
};

Lets go back to the main again.

int main()
{
   A a1;
   a1.x = 1;
   //do something on a1
   A a2;
   a2.x++;
   //do something on a2
}

Then a1 and a2 would share the same copy of int x whereby any operations on x in a1 would directly influence the operations of x in a2. So if I was to do this

int main()
{
   A a1;
   a1.x = 1;
   //do something on a1
   cout << a1.x << endl; //this would be 1
   A a2;
   a2.x++;
   cout << a2.x << endl; //this would be 2 
   //do something on a2
}

Both instances of the class A share static variables and functions. Hope this answers your question. My limited knowledge of C allows me to say that defining a function or variable as static means it is only visible to the file that the function or variable is defined as static in. But this would be better answered by a C guy and not me. C++ allows both C and C++ ways of declaring your variables as static because its completely backwards compatible with C.

How to reduce the image file size using PIL

A built-in parameter for saving JPEGs and PNGs is optimize.

 >>> from PIL import Image
 # My image is a 200x374 jpeg that is 102kb large
 >>> foo = Image.open("path\\to\\image.jpg")
 >>> foo.size
  (200,374)
 # I downsize the image with an ANTIALIAS filter (gives the highest quality)
 >>> foo = foo.resize((160,300),Image.ANTIALIAS)
 >>> foo.save("path\\to\\save\\image_scaled.jpg",quality=95)
 # The saved downsized image size is 24.8kb
 >>> foo.save("path\\to\\save\\image_scaled_opt.jpg",optimize=True,quality=95)
 # The saved downsized image size is 22.9kb

The optimize flag will do an extra pass on the image to find a way to reduce its size as much as possible. 1.9kb might not seem like much, but over hundreds/thousands of pictures, it can add up.

Now to try and get it down to 5kb to 10 kb, you can change the quality value in the save options. Using a quality of 85 instead of 95 in this case would yield: Unoptimized: 15.1kb Optimized : 14.3kb Using a quality of 75 (default if argument is left out) would yield: Unoptimized: 11.8kb Optimized : 11.2kb

I prefer quality 85 with optimize because the quality isn't affected much, and the file size is much smaller.

SQL subquery with COUNT help

SELECT e.*,
       cnt.colCount 
FROM eventsTable e
INNER JOIN (
           select columnName,count(columnName) as colCount
           from eventsTable e2 
          group by columnName
           ) as cnt on cnt.columnName = e.columnName
WHERE e.columnName='Business'

-- Added space

Sort a list of tuples by 2nd item (integer value)

The fact that the sort values in the OP are integers isn't relevant to the question per se. In other words, the accepted answer would work if the sort value was text. I bring this up to also point out that the sort can be modified during the sort (for example, to account for upper and lower case).

>>> sorted([(121, 'abc'), (231, 'def'), (148, 'ABC'), (221, 'DEF')], key=lambda x: x[1])
[(148, 'ABC'), (221, 'DEF'), (121, 'abc'), (231, 'def')]
>>> sorted([(121, 'abc'), (231, 'def'), (148, 'ABC'), (221, 'DEF')], key=lambda x: str.lower(x[1]))
[(121, 'abc'), (148, 'ABC'), (231, 'def'), (221, 'DEF')]

Why is there still a row limit in Microsoft Excel?

In a word - speed. An index for up to a million rows fits in a 32-bit word, so it can be used efficiently on 32-bit processors. Function arguments that fit in a CPU register are extremely efficient, while ones that are larger require accessing memory on each function call, a far slower operation. Updating a spreadsheet can be an intensive operation involving many cell references, so speed is important. Besides, the Excel team expects that anyone dealing with more than a million rows will be using a database rather than a spreadsheet.

Regex select all text between tags

<pre>([\r\n\s]*(?!<\w+.*[\/]*>).*[\r\n\s]*|\s*[\r\n\s]*)<code\s+(?:class="(\w+|\w+\s*.+)")>(((?!<\/code>)[\s\S])*)<\/code>[\r\n\s]*((?!<\w+.*[\/]*>).*|\s*)[\r\n\s]*<\/pre>

How can jQuery deferred be used?

Another example using Deferreds to implement a cache for any kind of computation (typically some performance-intensive or long-running tasks):

var ResultsCache = function(computationFunction, cacheKeyGenerator) {
    this._cache = {};
    this._computationFunction = computationFunction;
    if (cacheKeyGenerator)
        this._cacheKeyGenerator = cacheKeyGenerator;
};

ResultsCache.prototype.compute = function() {
    // try to retrieve computation from cache
    var cacheKey = this._cacheKeyGenerator.apply(this, arguments);
    var promise = this._cache[cacheKey];

    // if not yet cached: start computation and store promise in cache 
    if (!promise) {
        var deferred = $.Deferred();
        promise = deferred.promise();
        this._cache[cacheKey] = promise;

        // perform the computation
        var args = Array.prototype.slice.call(arguments);
        args.push(deferred.resolve);
        this._computationFunction.apply(null, args);
    }

    return promise;
};

// Default cache key generator (works with Booleans, Strings, Numbers and Dates)
// You will need to create your own key generator if you work with Arrays etc.
ResultsCache.prototype._cacheKeyGenerator = function(args) {
    return Array.prototype.slice.call(arguments).join("|");
};

Here is an example of using this class to perform some (simulated heavy) calculation:

// The addingMachine will add two numbers
var addingMachine = new ResultsCache(function(a, b, resultHandler) {
    console.log("Performing computation: adding " + a + " and " + b);
    // simulate rather long calculation time by using a 1s timeout
    setTimeout(function() {
        var result = a + b;
        resultHandler(result);
    }, 1000);
});

addingMachine.compute(2, 4).then(function(result) {
    console.log("result: " + result);
});

addingMachine.compute(1, 1).then(function(result) {
    console.log("result: " + result);
});

// cached result will be used
addingMachine.compute(2, 4).then(function(result) {
    console.log("result: " + result);
});

The same underlying cache could be used to cache Ajax requests:

var ajaxCache = new ResultsCache(function(id, resultHandler) {
    console.log("Performing Ajax request for id '" + id + "'");
    $.getJSON('http://jsfiddle.net/echo/jsonp/?callback=?', {value: id}, function(data) {
        resultHandler(data.value);
    });
});

ajaxCache.compute("anID").then(function(result) {
    console.log("result: " + result);
});

ajaxCache.compute("anotherID").then(function(result) {
    console.log("result: " + result);
});

// cached result will be used
ajaxCache.compute("anID").then(function(result) {
    console.log("result: " + result);
});

You can play with the above code in this jsFiddle.

Trigger a button click with JavaScript on the Enter key in a text box

document.onkeypress = function (e) {
 e = e || window.event;
 var charCode = (typeof e.which == "number") ? e.which : e.keyCode;
 if (charCode == 13) {

        // Do something here
        printResult();
    }
};

Heres my two cents. I am working on an app for Windows 8 and want the button to register a click event when I press the Enter button. I am doing this in JS. I tried a couple of suggestions, but had issues. This works just fine.

Oracle - What TNS Names file am I using?

Shouldn't it always be "$ORACLE_ HOME/network/admin/tnsnames.ora"? Then you can just do "echo $oracle_ home" or the *nix equivalent.

@Pete Holberton You are entirely correct. Which reminds me, there's another monkey wrench in the works called TWO_ TASK

According http://www.orafaq.com/wiki/TNS_ADMIN
TNS_ADMIN is an environment variable that points to the directory where the SQL*Net configuration files (like sqlnet.ora and tnsnames.ora) are located.

How to get a value from a Pandas DataFrame and not the index and object type

import pandas as pd

dataset = pd.read_csv("data.csv")
values = list(x for x in dataset["column name"])

>>> values[0]
'item_0'

edit:

actually, you can just index the dataset like any old array.

import pandas as pd

dataset = pd.read_csv("data.csv")
first_value = dataset["column name"][0]

>>> print(first_value)
'item_0'

open program minimized via command prompt

The answer is simple. Just look at the image.

enter image description here

Find OpenCV Version Installed on Ubuntu

You can look at the headers or libs installed. pkg-config can tell you where they are:

pkg-config --cflags opencv
pkg-config --libs opencv

Alternatively you can write a simple program and print the following defs:

CV_MAJOR_VERSION
CV_MINOR_VERSION

A similar question has been also asked here:

MassAssignmentException in Laravel

Just add Eloquent::unguard(); in the top of the run method when you do a seed, no need to create an $fillable array in all the models you have to seed.

Normally this is already specified in the DatabaseSeeder class. However because you're calling the UsersTableSeeder directly:

php artisan db:seed --class="UsersTableSeeder"

Eloquent::unguard(); isn't being called and gives the error.

Java web start - Unable to load resource

I'm not sure exactly what the problem is, but I have looked at one of my jnlp files and I have put in the full path to each of my jar files. (I have a velocity template that generates the app.jnlp file which places it in all the correct places when my maven build runs)

One thing I have seen happen is that the jnlp file is re-downloaded by the by the webstart runtime, and it uses the href attribute (which is left blank in your jnlp file) to re-download the file. I would start there, and try adding the full path into the jnlp files too...I've found webstart to be a fickle mistress!

Logout button php

When you want to destroy a session completely, you need to do more then just

session_destroy();

First, you should unset any session variables. Then you should destroy the session followed by closing the write of the session. This can be done by the following:

<?php
session_start();
unset($_SESSION);
session_destroy();
session_write_close();
header('Location: /');
die;
?>

The reason you want have a separate script for a logout is so that you do not accidently execute it on the page. So make a link to your logout script, then the header will redirect to the root of your site.

Edit:

You need to remove the () from your exit code near the top of your script. it should just be

exit;

Angular - POST uploaded file

Looking onto this issue Github - Request/Upload progress handling via @angular/http, angular2 http does not support file upload yet.

For very basic file upload I created such service function as a workaround (using ???????'s answer):

  uploadFile(file:File):Promise<MyEntity> {
    return new Promise((resolve, reject) => {

        let xhr:XMLHttpRequest = new XMLHttpRequest();
        xhr.onreadystatechange = () => {
            if (xhr.readyState === 4) {
                if (xhr.status === 200) {
                    resolve(<MyEntity>JSON.parse(xhr.response));
                } else {
                    reject(xhr.response);
                }
            }
        };

        xhr.open('POST', this.getServiceUrl(), true);

        let formData = new FormData();
        formData.append("file", file, file.name);
        xhr.send(formData);
    });
}

Received fatal alert: handshake_failure through SSLHandshakeException

I found an HTTPS server which failed in this way if my Java client process was configured with

-Djsse.enableSNIExtension=false

The connection failed with handshake_failure after the ServerHello had finished successfully but before the data stream started.

There was no clear error message that identified the problem, the error just looked like

main, READ: TLSv1.2 Alert, length = 2
main, RECV TLSv1.2 ALERT:  fatal, handshake_failure
%% Invalidated:  [Session-3, TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384]
main, called closeSocket()
main, handling exception: javax.net.ssl.SSLHandshakeException: Received fatal alert: handshake_failure

I isolated the issue by trying with and without the "-Djsse.enableSNIExtension=false" option

Getting "cannot find Symbol" in Java project in Intellij

This is likely to be your ../src folder is not marked as a "source" folder in Intellij IDEA, so it doesn't know to look there to find your class. You can right click the folder in the project explorer and choose "mark as source folder" to fix this.

How to get single value of List<object>

You can access the fields by indexing the object array:

foreach (object[] item in selectedValues)
{
  idTextBox.Text = item[0];
  titleTextBox.Text = item[1];
  contentTextBox.Text = item[2];
}

That said, you'd be better off storing the fields in a small class of your own if the number of items is not dynamic:

public class MyObject
{
    public int Id { get; set; }
    public string Title { get; set; }
    public string Content { get; set; }
}

Then you can do:

foreach (MyObject item in selectedValues)
{
  idTextBox.Text = item.Id;
  titleTextBox.Text = item.Title;
  contentTextBox.Text = item.Content;
}

Autoplay an audio with HTML5 embed tag while the player is invisible

Alternatively you can try the basic thing to get your need,

<audio autoplay loop>
      <source src="johann_sebastian_bach_air.mp3">
</audio>

For further reference click here

.htaccess, order allow, deny, deny from all: confused?

This is a quite confusing way of using Apache configuration directives.

Technically, the first bit is equivalent to

Allow From All

This is because Order Deny,Allow makes the Deny directive evaluated before the Allow Directives. In this case, Deny and Allow conflict with each other, but Allow, being the last evaluated will match any user, and access will be granted.

Now, just to make things clear, this kind of configuration is BAD and should be avoided at all cost, because it borders undefined behaviour.

The Limit sections define which HTTP methods have access to the directory containing the .htaccess file.

Here, GET and POST methods are allowed access, and PUT and DELETE methods are denied access. Here's a link explaining what the various HTTP methods are: http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html

However, it's more than often useless to use these limitations as long as you don't have custom CGI scripts or Apache modules that directly handle the non-standard methods (PUT and DELETE), since by default, Apache does not handle them at all.

It must also be noted that a few other methods exist that can also be handled by Limit, namely CONNECT, OPTIONS, PATCH, PROPFIND, PROPPATCH, MKCOL, COPY, MOVE, LOCK, and UNLOCK.

The last bit is also most certainly useless, since any correctly configured Apache installation contains the following piece of configuration (for Apache 2.2 and earlier):

#
# The following lines prevent .htaccess and .htpasswd files from being 
# viewed by Web clients. 
#
<Files ~ "^\.ht">
    Order allow,deny
    Deny from all
    Satisfy all
</Files>

which forbids access to any file beginning by ".ht".

The equivalent Apache 2.4 configuration should look like:

<Files ~ "^\.ht">
    Require all denied
</Files>

How to delete all rows from all tables in a SQL Server database?

You could delete all the rows from all tables using an approach like Rubens suggested, or you could just drop and recreate all the tables. Always a good idea to have the full db creation scripts anyway so that may be the easiest/quickest method.

Build .NET Core console application to output an EXE

The following will produce, in the output directory,

  • all the package references
  • the output assembly
  • the bootstrapping exe

But it does not contain all .NET Core runtime assemblies.

<PropertyGroup>
  <Temp>$(SolutionDir)\packaging\</Temp>
</PropertyGroup>

<ItemGroup>
  <BootStrapFiles Include="$(Temp)hostpolicy.dll;$(Temp)$(ProjectName).exe;$(Temp)hostfxr.dll;"/>
</ItemGroup>

<Target Name="GenerateNetcoreExe"
        AfterTargets="Build"
        Condition="'$(IsNestedBuild)' != 'true'">
  <RemoveDir Directories="$(Temp)" />
  <Exec
    ConsoleToMSBuild="true"
    Command="dotnet build $(ProjectPath) -r win-x64 /p:CopyLocalLockFileAssemblies=false;IsNestedBuild=true --output $(Temp)" >
    <Output TaskParameter="ConsoleOutput" PropertyName="OutputOfExec" />
  </Exec>
  <Copy
    SourceFiles="@(BootStrapFiles)"
    DestinationFolder="$(OutputPath)"
  />

</Target>

I wrapped it up in a sample here: https://github.com/SimonCropp/NetCoreConsole

How to slice a Pandas Data Frame by position?

You can also do as a convenience:

df[:10]

How do I get the name of the active user via the command line in OS X?

I'm pretty sure the terminal in OS X is just like unix, so the command would be:

whoami

I don't have a mac on me at the moment so someone correct me if I'm wrong.

NOTE - The whoami utility has been obsoleted, and is equivalent to id -un. It will give you the current user

The type or namespace name could not be found

PrjForm was set to ".Net Framework 4 Client Profile" I changed it to ".Net Framework 4", and now I have a successful build.

This worked for me too. Thanks a lot. I was trying an RDF example for dotNet where in I downloaded kit from dotnetrdf.

NET4 Client Profile: Always target NET4 Client Profile for all your client desktop applications (including Windows Forms and WPF apps).

NET4 Full framework: Target NET4 Full only if the features or assemblies that your app need are not included in the Client Profile. This includes: If you are building Server apps, Such as:

  • ASP.Net apps
  • Server-side ASMX based web services

If you use legacy client scenarios, Such as: o Use System.Data.OracleClient.dll which is deprecated in NET4 and not included in the Client Profile.

  • Use legacy Windows Workflow Foundation 3.0 or 3.5 (WF3.0 , WF3.5)

If you targeting developer scenarios and need tool such as MSBuild or need access to design assemblies such as System.Design.dll

Consistency of hashCode() on a Java string

The hashcode will be calculated based on the ASCII values of the characters in the String.

This is the implementation in the String Class is as follows

public int hashCode() {
    int h = hash;
    if (h == 0 && value.length > 0) {
        hash = h = isLatin1() ? StringLatin1.hashCode(value)
                              : StringUTF16.hashCode(value);
    }
    return h;
}

Collisions in hashcode are unavoidable. For example, the strings "Ea" and "FB" give the same hashcode as 2236

JavaScript Number Split into individual digits

A functional approach in order to get digits from a number would be to get a string from your number, split it into an array (of characters) and map each element back into a number.

For example:

var number = 123456;

var array = number.toString()
.split('')
.map(function(item, index) {
   return parseInt(item);
});

console.log(array); // returns [1, 2, 3, 4, 5, 6]

If you also need to sum all digits, you can append the reduce() method to the previous code:

var num = 123456;

var array = num.toString()
.split('')
.map(function(item, index) {
   return parseInt(item);
})
.reduce(function(previousValue, currentValue, index, array) {
  return previousValue + currentValue;
}, 0);

console.log(array); // returns 21

As an alternative, with ECMAScript 2015 (6th Edition), you can use arrow functions:

var number = 123456;
var array = number.toString().split('').map((item, index) => parseInt(item));
console.log(array); // returns [1, 2, 3, 4, 5, 6]

If you need to sum all digits, you can append the reduce() method to the previous code:

var num = 123456;

var result = num.toString()
.split('')
.map((item, index) => parseInt(item))
.reduce((previousValue, currentValue) => previousValue + currentValue, 0);

console.log(result); // returns 21

How can I make Bootstrap 4 columns all the same height?

You just have to use class="row-eq-height" with your class="row" to get equal height columns for previous bootstrap versions.

but with bootstrap 4 this comes natively.

check this link --http://getbootstrap.com.vn/examples/equal-height-columns/

Keras, How to get the output of each layer?

Following looks very simple to me:

model.layers[idx].output

Above is a tensor object, so you can modify it using operations that can be applied to a tensor object.

For example, to get the shape model.layers[idx].output.get_shape()

idx is the index of the layer and you can find it from model.summary()

How to generate Javadoc from command line

You can refer the javadoc 8 documentation

I think what you are looking at is something like this:

javadoc -d C:\javadoc\test com.test

How to get the fields in an Object via reflection?

Here's a quick and dirty method that does what you want in a generic way. You'll need to add exception handling and you'll probably want to cache the BeanInfo types in a weakhashmap.

public Map<String, Object> getNonNullProperties(final Object thingy) {
    final Map<String, Object> nonNullProperties = new TreeMap<String, Object>();
    try {
        final BeanInfo beanInfo = Introspector.getBeanInfo(thingy
                .getClass());
        for (final PropertyDescriptor descriptor : beanInfo
                .getPropertyDescriptors()) {
            try {
                final Object propertyValue = descriptor.getReadMethod()
                        .invoke(thingy);
                if (propertyValue != null) {
                    nonNullProperties.put(descriptor.getName(),
                            propertyValue);
                }
            } catch (final IllegalArgumentException e) {
                // handle this please
            } catch (final IllegalAccessException e) {
                // and this also
            } catch (final InvocationTargetException e) {
                // and this, too
            }
        }
    } catch (final IntrospectionException e) {
        // do something sensible here
    }
    return nonNullProperties;
}

See these references:

How can I use UIColorFromRGB in Swift?

import Cocoa
class ViewController: NSViewController{
     override func viewDidLoad() {
            super.viewDidLoad()
    self.view.wantsLayer = true
    self.view.layer?.backgroundColor = NSColor(hexString: "#4d9b48").cgColor

}
extension NSColor {

            convenience init(hexString: String, alpha: CGFloat = 1.0) {
                  let hexString: String = hexString.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)
                  let scanner = Scanner(string: hexString)
                  if (hexString.hasPrefix("#")) {
                      scanner.scanLocation = 1
                  }
                  var color: UInt32 = 0
                  scanner.scanHexInt32(&color)
                  let mask = 0x000000FF
                  let r = Int(color >> 16) & mask
                  let g = Int(color >> 8) & mask
                  let b = Int(color) & mask
                  let red   = CGFloat(r) / 255.0
                  let green = CGFloat(g) / 255.0
                  let blue  = CGFloat(b) / 255.0
                  self.init(red:red, green:green, blue:blue, alpha:alpha)
              }
              func toHexString() -> String {
                  var r:CGFloat = 0
                  var g:CGFloat = 0
                  var b:CGFloat = 0
                  var a:CGFloat = 0
                  getRed(&r, green: &g, blue: &b, alpha: &a)
                  let rgb:Int = (Int)(r*255)<<16 | (Int)(g*255)<<8 | (Int)(b*255)<<0
                  return String(format:"#%06x", rgb)

            }
        }