Programs & Examples On #Mini language

Error while installing json gem 'mkmf.rb can't find header files for ruby'

In case that you are using ruby 2.0 or 2.2 (thanks @patrick-davey) or 2.3 (thanks @juanitofatas).

sudo apt-get install ruby-dev
sudo apt-get install ruby2.0-dev
sudo apt-get install ruby2.2-dev
sudo apt-get install ruby2.3-dev

And you get the pattern here...

Get domain name from given url

One of the way I did and worked for all of the cases is using Guava Library and regex in combination.

public static String getDomainNameWithGuava(String url) throws MalformedURLException, 
  URISyntaxException {
    String host =new URL(url).getHost();
    String domainName="";
    try{
        domainName = InternetDomainName.from(host).topPrivateDomain().toString();
    }catch (IllegalStateException | IllegalArgumentException e){
        domainName= getDomain(url,true);
    }
    return domainName;
}

getDomain() can be any common method with regex.

"installation of package 'FILE_PATH' had non-zero exit status" in R

I had the same problem, but the answer from @little_chemist helped me sorting it out. When installing packages from a file in a unix OS (Ubuntu 18.04 for me), the file can not be zipped. You are using:

install.packages("/home/p/Research/14_bivpois-Rcode.zip", repos = NULL, type="source")

I noticed the solution was as simple as unzipping the package. Additionally, unzip all (installation related?) packages inside, as @little_chemist points out. Then use install.packages:

install.packages("/home/p/Research/14_bivpois-Rcode", repos = NULL, type="source")

Hope it helps!

What is the difference between Bower and npm?

My team moved away from Bower and migrated to npm because:

  • Programmatic usage was painful
  • Bower's interface kept changing
  • Some features, like the url shorthand, are entirely broken
  • Using both Bower and npm in the same project is painful
  • Keeping bower.json version field in sync with git tags is painful
  • Source control != package management
  • CommonJS support is not straightforward

For more details, see "Why my team uses npm instead of bower".

Cannot catch toolbar home button click event

I think the correct solution with support library 21 is the following

// action_bar is def resource of appcompat; 
// if you have not provided your own toolbar I mean  
Toolbar toolbar = (Toolbar) findViewById(R.id.action_bar);
if (toolbar != null) {
    // change home icon if you wish
    toolbar.setLogo(this.getResValues().homeIconDrawable());
    toolbar.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            //catch here title and home icon click                          
        }                       
    });                 
}

convert php date to mysql format

There is several options.

Either convert it to timestamp and use as instructed in other posts with strtotime() or use MySQL’s date parsing option

TypeError: ObjectId('') is not JSON serializable

You should define you own JSONEncoder and using it:

import json
from bson import ObjectId

class JSONEncoder(json.JSONEncoder):
    def default(self, o):
        if isinstance(o, ObjectId):
            return str(o)
        return json.JSONEncoder.default(self, o)

JSONEncoder().encode(analytics)

It's also possible to use it in the following way.

json.encode(analytics, cls=JSONEncoder)

How to retrieve a file from a server via SFTP?

A nice abstraction on top of Jsch is Apache commons-vfs which offers a virtual filesystem API that makes accessing and writing SFTP files almost transparent. Worked well for us.

PHP check if date between two dates

function get_format($df) {

    $str = '';
    $str .= ($df->invert == 1) ? ' - ' : '';
    if ($df->y > 0) {
        // years
        $str .= ($df->y > 1) ? $df->y . ' Years ' : $df->y . ' Year ';
    } if ($df->m > 0) {
        // month
        $str .= ($df->m > 1) ? $df->m . ' Months ' : $df->m . ' Month ';
    } if ($df->d > 0) {
        // days
        $str .= ($df->d > 1) ? $df->d . ' Days ' : $df->d . ' Day ';
    } 

    echo $str;
}

$yr=$year;
$dates=$dor;
$myyear='+'.$yr.' years';
$new_date = date('Y-m-d', strtotime($myyear, strtotime($dates)));
$date1 = new DateTime("$new_date");
$date2 = new DateTime("now");
$diff = $date2->diff($date1);

How to convert a number to string and vice versa in C++

Update for C++11

As of the C++11 standard, string-to-number conversion and vice-versa are built in into the standard library. All the following functions are present in <string> (as per paragraph 21.5).

string to numeric

float              stof(const string& str, size_t *idx = 0);
double             stod(const string& str, size_t *idx = 0);
long double        stold(const string& str, size_t *idx = 0);
int                stoi(const string& str, size_t *idx = 0, int base = 10);
long               stol(const string& str, size_t *idx = 0, int base = 10);
unsigned long      stoul(const string& str, size_t *idx = 0, int base = 10);
long long          stoll(const string& str, size_t *idx = 0, int base = 10);
unsigned long long stoull(const string& str, size_t *idx = 0, int base = 10);

Each of these take a string as input and will try to convert it to a number. If no valid number could be constructed, for example because there is no numeric data or the number is out-of-range for the type, an exception is thrown (std::invalid_argument or std::out_of_range).

If conversion succeeded and idx is not 0, idx will contain the index of the first character that was not used for decoding. This could be an index behind the last character.

Finally, the integral types allow to specify a base, for digits larger than 9, the alphabet is assumed (a=10 until z=35). You can find more information about the exact formatting that can parsed here for floating-point numbers, signed integers and unsigned integers.

Finally, for each function there is also an overload that accepts a std::wstring as it's first parameter.

numeric to string

string to_string(int val);
string to_string(unsigned val);
string to_string(long val);
string to_string(unsigned long val);
string to_string(long long val);
string to_string(unsigned long long val);
string to_string(float val);
string to_string(double val);
string to_string(long double val);

These are more straightforward, you pass the appropriate numeric type and you get a string back. For formatting options you should go back to the C++03 stringsream option and use stream manipulators, as explained in an other answer here.

As noted in the comments these functions fall back to a default mantissa precision that is likely not the maximum precision. If more precision is required for your application it's also best to go back to other string formatting procedures.

There are also similar functions defined that are named to_wstring, these will return a std::wstring.

Way to read first few lines for pandas dataframe

I think you can use the nrows parameter. From the docs:

nrows : int, default None

    Number of rows of file to read. Useful for reading pieces of large files

which seems to work. Using one of the standard large test files (988504479 bytes, 5344499 lines):

In [1]: import pandas as pd

In [2]: time z = pd.read_csv("P00000001-ALL.csv", nrows=20)
CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s
Wall time: 0.00 s

In [3]: len(z)
Out[3]: 20

In [4]: time z = pd.read_csv("P00000001-ALL.csv")
CPU times: user 27.63 s, sys: 1.92 s, total: 29.55 s
Wall time: 30.23 s

Is jQuery $.browser Deprecated?

Updated! 3/24/2015 (scroll below hr)

lonesomeday's answer is absolutely correct, I just thought I would add this tidbit. I had made a method a while back for getting browser in Vanilla JS and eventually curved it to replace jQuery.browser in later versions of jQuery. It does not interfere with any part of the new jQuery lib, but provides the same functionality of the traditional jQuery.browser object, as well as some other little features.


New Extended Version!

Is much more thorough for newer browser. Also, 90+% accuracy on mobile testing! I won't say 100%, as I haven't tested on every mobile browser, but new feature adds $.browser.mobile boolean/string. It's false if not mobile, else it will be a String name for the mobile device or browser (Best Guesss like: Android, RIM Tablet, iPod, etc...).

One possible caveat, may not work with some older (unsupported) browsers as it is completely reliant on userAgent string.

JS Minified

/* quick & easy cut & paste */
;;(function($){if(!$.browser&&1.9<=parseFloat($.fn.jquery)){var a={browser:void 0,version:void 0,mobile:!1};navigator&&navigator.userAgent&&(a.ua=navigator.userAgent,a.webkit=/WebKit/i.test(a.ua),a.browserArray="MSIE Chrome Opera Kindle Silk BlackBerry PlayBook Android Safari Mozilla Nokia".split(" "),/Sony[^ ]*/i.test(a.ua)?a.mobile="Sony":/RIM Tablet/i.test(a.ua)?a.mobile="RIM Tablet":/BlackBerry/i.test(a.ua)?a.mobile="BlackBerry":/iPhone/i.test(a.ua)?a.mobile="iPhone":/iPad/i.test(a.ua)?a.mobile="iPad":/iPod/i.test(a.ua)?a.mobile="iPod":/Opera Mini/i.test(a.ua)?a.mobile="Opera Mini":/IEMobile/i.test(a.ua)?a.mobile="IEMobile":/BB[0-9]{1,}; Touch/i.test(a.ua)?a.mobile="BlackBerry":/Nokia/i.test(a.ua)?a.mobile="Nokia":/Android/i.test(a.ua)&&(a.mobile="Android"),/MSIE|Trident/i.test(a.ua)?(a.browser="MSIE",a.version=/MSIE/i.test(navigator.userAgent)&&0<parseFloat(a.ua.split("MSIE")[1].replace(/[^0-9\.]/g,""))?parseFloat(a.ua.split("MSIE")[1].replace(/[^0-9\.]/g,"")):"Edge",/Trident/i.test(a.ua)&&/rv:([0-9]{1,}[\.0-9]{0,})/.test(a.ua)&&(a.version=parseFloat(a.ua.match(/rv:([0-9]{1,}[\.0-9]{0,})/)[1].replace(/[^0-9\.]/g,"")))):/Chrome/.test(a.ua)?(a.browser="Chrome",a.version=parseFloat(a.ua.split("Chrome/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Opera/.test(a.ua)?(a.browser="Opera",a.version=parseFloat(a.ua.split("Version/")[1].replace(/[^0-9\.]/g,""))):/Kindle|Silk|KFTT|KFOT|KFJWA|KFJWI|KFSOWI|KFTHWA|KFTHWI|KFAPWA|KFAPWI/i.test(a.ua)?(a.mobile="Kindle",/Silk/i.test(a.ua)?(a.browser="Silk",a.version=parseFloat(a.ua.split("Silk/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Kindle/i.test(a.ua)&&/Version/i.test(a.ua)&&(a.browser="Kindle",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,"")))):/BlackBerry/.test(a.ua)?(a.browser="BlackBerry",a.version=parseFloat(a.ua.split("/")[1].replace(/[^0-9\.]/g,""))):/PlayBook/.test(a.ua)?(a.browser="PlayBook",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/BB[0-9]{1,}; Touch/.test(a.ua)?(a.browser="Blackberry",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Android/.test(a.ua)?(a.browser="Android",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Safari/.test(a.ua)?(a.browser="Safari",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Firefox/.test(a.ua)?(a.browser="Mozilla",a.version=parseFloat(a.ua.split("Firefox/")[1].replace(/[^0-9\.]/g,""))):/Nokia/.test(a.ua)&&(a.browser="Nokia",a.version=parseFloat(a.ua.split("Browser")[1].replace(/[^0-9\.]/g,""))));if(a.browser)for(var b in a.browserArray)a[a.browserArray[b].toLowerCase()]=a.browser==a.browserArray[b];$.extend(!0,$.browser={},a)}})(jQuery);
/* quick & easy cut & paste */

jsFiddle "jQuery Plugin: Get Browser (Extended Alt Edition)"

_x000D_
_x000D_
/** jQuery.browser_x000D_
 * @author J.D. McKinstry (2014)_x000D_
 * @description Made to replicate older jQuery.browser command in jQuery versions 1.9+_x000D_
 * @see http://jsfiddle.net/SpYk3/wsqfbe4s/_x000D_
 *_x000D_
 * @extends jQuery_x000D_
 * @namespace jQuery.browser_x000D_
 * @example jQuery.browser.browser == 'browserNameInLowerCase'_x000D_
 * @example jQuery.browser.version_x000D_
 * @example jQuery.browser.mobile @returns BOOLEAN_x000D_
 * @example jQuery.browser['browserNameInLowerCase']_x000D_
 * @example jQuery.browser.chrome @returns BOOLEAN_x000D_
 * @example jQuery.browser.safari @returns BOOLEAN_x000D_
 * @example jQuery.browser.opera @returns BOOLEAN_x000D_
 * @example jQuery.browser.msie @returns BOOLEAN_x000D_
 * @example jQuery.browser.mozilla @returns BOOLEAN_x000D_
 * @example jQuery.browser.webkit @returns BOOLEAN_x000D_
 * @example jQuery.browser.ua @returns navigator.userAgent String_x000D_
 */_x000D_
;;(function($){if(!$.browser&&1.9<=parseFloat($.fn.jquery)){var a={browser:void 0,version:void 0,mobile:!1};navigator&&navigator.userAgent&&(a.ua=navigator.userAgent,a.webkit=/WebKit/i.test(a.ua),a.browserArray="MSIE Chrome Opera Kindle Silk BlackBerry PlayBook Android Safari Mozilla Nokia".split(" "),/Sony[^ ]*/i.test(a.ua)?a.mobile="Sony":/RIM Tablet/i.test(a.ua)?a.mobile="RIM Tablet":/BlackBerry/i.test(a.ua)?a.mobile="BlackBerry":/iPhone/i.test(a.ua)?a.mobile="iPhone":/iPad/i.test(a.ua)?a.mobile="iPad":/iPod/i.test(a.ua)?a.mobile="iPod":/Opera Mini/i.test(a.ua)?a.mobile="Opera Mini":/IEMobile/i.test(a.ua)?a.mobile="IEMobile":/BB[0-9]{1,}; Touch/i.test(a.ua)?a.mobile="BlackBerry":/Nokia/i.test(a.ua)?a.mobile="Nokia":/Android/i.test(a.ua)&&(a.mobile="Android"),/MSIE|Trident/i.test(a.ua)?(a.browser="MSIE",a.version=/MSIE/i.test(navigator.userAgent)&&0<parseFloat(a.ua.split("MSIE")[1].replace(/[^0-9\.]/g,""))?parseFloat(a.ua.split("MSIE")[1].replace(/[^0-9\.]/g,"")):"Edge",/Trident/i.test(a.ua)&&/rv:([0-9]{1,}[\.0-9]{0,})/.test(a.ua)&&(a.version=parseFloat(a.ua.match(/rv:([0-9]{1,}[\.0-9]{0,})/)[1].replace(/[^0-9\.]/g,"")))):/Chrome/.test(a.ua)?(a.browser="Chrome",a.version=parseFloat(a.ua.split("Chrome/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Opera/.test(a.ua)?(a.browser="Opera",a.version=parseFloat(a.ua.split("Version/")[1].replace(/[^0-9\.]/g,""))):/Kindle|Silk|KFTT|KFOT|KFJWA|KFJWI|KFSOWI|KFTHWA|KFTHWI|KFAPWA|KFAPWI/i.test(a.ua)?(a.mobile="Kindle",/Silk/i.test(a.ua)?(a.browser="Silk",a.version=parseFloat(a.ua.split("Silk/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Kindle/i.test(a.ua)&&/Version/i.test(a.ua)&&(a.browser="Kindle",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,"")))):/BlackBerry/.test(a.ua)?(a.browser="BlackBerry",a.version=parseFloat(a.ua.split("/")[1].replace(/[^0-9\.]/g,""))):/PlayBook/.test(a.ua)?(a.browser="PlayBook",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/BB[0-9]{1,}; Touch/.test(a.ua)?(a.browser="Blackberry",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Android/.test(a.ua)?(a.browser="Android",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Safari/.test(a.ua)?(a.browser="Safari",a.version=parseFloat(a.ua.split("Version/")[1].split("Safari")[0].replace(/[^0-9\.]/g,""))):/Firefox/.test(a.ua)?(a.browser="Mozilla",a.version=parseFloat(a.ua.split("Firefox/")[1].replace(/[^0-9\.]/g,""))):/Nokia/.test(a.ua)&&(a.browser="Nokia",a.version=parseFloat(a.ua.split("Browser")[1].replace(/[^0-9\.]/g,""))));if(a.browser)for(var b in a.browserArray)a[a.browserArray[b].toLowerCase()]=a.browser==a.browserArray[b];$.extend(!0,$.browser={},a)}})(jQuery);_x000D_
/* - - - - - - - - - - - - - - - - - - - */_x000D_
_x000D_
var b = $.browser;_x000D_
console.log($.browser);    //    see console, working example of jQuery Plugin_x000D_
console.log($.browser.chrome);_x000D_
_x000D_
for (var x in b) {_x000D_
    if (x != 'init')_x000D_
        $('<tr />').append(_x000D_
            $('<th />', { text: x }),_x000D_
            $('<td />', { text: b[x] })_x000D_
        ).appendTo($('table'));_x000D_
}
_x000D_
table { border-collapse: collapse; }_x000D_
th, td { border: 1px solid; padding: .25em .5em; vertical-align: top; }_x000D_
th { text-align: right; }_x000D_
_x000D_
textarea { height: 500px; width: 100%; }
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>_x000D_
<table></table>
_x000D_
_x000D_
_x000D_

Serializing to JSON in jQuery

I haven't used it but you might want to try the jQuery plugin written by Mark Gibson

It adds the two functions: $.toJSON(value), $.parseJSON(json_str, [safe]).

insert multiple rows into DB2 database

None of the above worked for me, the only one working was

insert into tableName  
select 11, 'BALOO' from sysibm.sysdummy1 union all
select 22, nullif('','') AS nullColumn from sysibm.sysdummy1

The nullif is used since it is not possible to pass null in the select statement otherwise.

error_log per Virtual Host?

Don't set error_log to where your syslog stuff goes, eg /var/log/apache2, because they errors will get intercepted by ErrorLog. Instead, create a subdir in your project folder for logs and do php_value error_log "/path/to/project/logs". This goes for both .htaccess files and vhosts. Also make sure you put php_flag log_errors on

C non-blocking keyboard input

Here's a function to do this for you. You need termios.h which comes with POSIX systems.

#include <termios.h>
void stdin_set(int cmd)
{
    struct termios t;
    tcgetattr(1,&t);
    switch (cmd) {
    case 1:
            t.c_lflag &= ~ICANON;
            break;
    default:
            t.c_lflag |= ICANON;
            break;
    }
    tcsetattr(1,0,&t);
}

Breaking this down: tcgetattr gets the current terminal information and stores it in t. If cmd is 1, the local input flag in t is set to non-blocking input. Otherwise it is reset. Then tcsetattr changes standard input to t.

If you don't reset standard input at the end of your program you will have problems in your shell.

Unable to load DLL (Module could not be found HRESULT: 0x8007007E)

Try to enter the full-path of the dll. If it doesn't work, try to copy the dll into the system32 folder.

C Programming: How to read the whole file contents into a buffer

Here is what I would recommend.

It should conform to C89, and be completely portable. In particular, it works also on pipes and sockets on POSIXy systems.

The idea is that we read the input in large-ish chunks (READALL_CHUNK), dynamically reallocating the buffer as we need it. We only use realloc(), fread(), ferror(), and free():

#include <stdlib.h>
#include <stdio.h>
#include <errno.h>

/* Size of each input chunk to be
   read and allocate for. */
#ifndef  READALL_CHUNK
#define  READALL_CHUNK  262144
#endif

#define  READALL_OK          0  /* Success */
#define  READALL_INVALID    -1  /* Invalid parameters */
#define  READALL_ERROR      -2  /* Stream error */
#define  READALL_TOOMUCH    -3  /* Too much input */
#define  READALL_NOMEM      -4  /* Out of memory */

/* This function returns one of the READALL_ constants above.
   If the return value is zero == READALL_OK, then:
     (*dataptr) points to a dynamically allocated buffer, with
     (*sizeptr) chars read from the file.
     The buffer is allocated for one extra char, which is NUL,
     and automatically appended after the data.
   Initial values of (*dataptr) and (*sizeptr) are ignored.
*/
int readall(FILE *in, char **dataptr, size_t *sizeptr)
{
    char  *data = NULL, *temp;
    size_t size = 0;
    size_t used = 0;
    size_t n;

    /* None of the parameters can be NULL. */
    if (in == NULL || dataptr == NULL || sizeptr == NULL)
        return READALL_INVALID;

    /* A read error already occurred? */
    if (ferror(in))
        return READALL_ERROR;

    while (1) {

        if (used + READALL_CHUNK + 1 > size) {
            size = used + READALL_CHUNK + 1;

            /* Overflow check. Some ANSI C compilers
               may optimize this away, though. */
            if (size <= used) {
                free(data);
                return READALL_TOOMUCH;
            }

            temp = realloc(data, size);
            if (temp == NULL) {
                free(data);
                return READALL_NOMEM;
            }
            data = temp;
        }

        n = fread(data + used, 1, READALL_CHUNK, in);
        if (n == 0)
            break;

        used += n;
    }

    if (ferror(in)) {
        free(data);
        return READALL_ERROR;
    }

    temp = realloc(data, used + 1);
    if (temp == NULL) {
        free(data);
        return READALL_NOMEM;
    }
    data = temp;
    data[used] = '\0';

    *dataptr = data;
    *sizeptr = used;

    return READALL_OK;
}

Above, I've used a constant chunk size, READALL_CHUNK == 262144 (256*1024). This means that in the worst case, up to 262145 chars are wasted (allocated but not used), but only temporarily. At the end, the function reallocates the buffer to the optimal size. Also, this means that we do four reallocations per megabyte of data read.

The 262144-byte default in the code above is a conservative value; it works well for even old minilaptops and Raspberry Pis and most embedded devices with at least a few megabytes of RAM available for the process. Yet, it is not so small that it slows down the operation (due to many read calls, and many buffer reallocations) on most systems.

For desktop machines at this time (2017), I recommend a much larger READALL_CHUNK, perhaps #define READALL_CHUNK 2097152 (2 MiB).

Because the definition of READALL_CHUNK is guarded (i.e., it is defined only if it is at that point in the code still undefined), you can override the default value at compile time, by using (in most C compilers) -DREADALL_CHUNK=2097152 command-line option -- but do check your compiler options for defining a preprocessor macro using command-line options.

Error 5 : Access Denied when starting windows service

After banging my had against my desk for a few hours trying to figure this out, somehow my "Main" method got emptied of it's code!

ServiceBase[] ServicesToRun;
ServicesToRun = new ServiceBase[] 
{ 
    new DMTestService()
};
ServiceBase.Run(ServicesToRun);

Other solutions I found:

  • Updating the .NET framework to 4.0
  • Making sure the service name inside the InitializeComponent() matches the installer service name property

    private void InitializeComponent()
    ...
    this.ServiceName = "DMTestService";
    
  • And a nice server restart doesn't hurt

Szhlopp

How to solve "Could not establish trust relationship for the SSL/TLS secure channel with authority"

Just fixed a similar issue.

I realized I had an application pool that was running under an account that only had reading permission over the certificate that it was used.

The .NET application could correctly retrieve the certificate but that exception was thrown only when GetRequestStream() was called.

Certificates permissions can be managed via MMC console

Parse date string and change format

>>> from_date="Mon Feb 15 2010"
>>> import time                
>>> conv=time.strptime(from_date,"%a %b %d %Y")
>>> time.strftime("%d/%m/%Y",conv)
'15/02/2010'

CSS - Syntax to select a class within an id

This will also work and you don't need the extra class:

#navigation li li {}

If you have a third level of LI's you may have to reset/override some of the styles they will inherit from the above selector. You can target the third level like so:

#navigation li li li {}

Regex lookahead, lookbehind and atomic groups

Grokking lookaround rapidly.
How to distinguish lookahead and lookbehind? Take 2 minutes tour with me:

(?=) - positive lookahead
(?<=) - positive lookbehind

Suppose

    A  B  C #in a line

Now, we ask B, Where are you?
B has two solutions to declare it location:

One, B has A ahead and has C bebind
Two, B is ahead(lookahead) of C and behind (lookhehind) A.

As we can see, the behind and ahead are opposite in the two solutions.
Regex is solution Two.

Finding elements not in a list

list1 = [1,2,3,4]; list2 = [0,3,3,6]

print set(list2) - set(list1)

How to render a DateTime object in a Twig template

Although you can use the

{{ game.gameDate|date('Y-m-d') }}

approach, keep in mind that this version does not honor the user locale, which should not be a problem with a site used by only users of one nationality. International users should display the game date totally different, like extending the \DateTime class, and adding a __toString() method to it that checks the locale and acts accordingly.

Edit:

As pointed out by @Nic in a comment, if you use the Intl extension of Twig, you will have a localizeddate filter available, which shows the date in the user’s locale. This way you can drop my previous idea of extending \DateTime.

pythonic way to do something N times without an index variable?

Use the _ variable, as I learned when I asked this question, for example:

# A long way to do integer exponentiation
num = 2
power = 3
product = 1
for _ in xrange(power):
    product *= num
print product

How to scroll to an element?

If you want to do it on page load you can use useLayoutEffect, and useRef.

import React, { useRef, useLayoutEffect } from 'react'

const ScrollDemo = () => {

   const myRef = useRef(null)

   useLayoutEffect(() => {
      window.scrollTo({
        behavior: "smooth",
        top: myRef.current.offsetTop,
      });
    }, [myRef.current]);

   return (
      <> 
         <div ref={myRef}>I wanna be seen</div>
      </>
   )
}

Can a unit test project load the target application's app.config file?

This is very easy.

  • Right click on your test project
  • Add-->Existing item
  • You can see a small arrow just beside the Add button
  • Select the config file click on "Add As Link"

How to calculate UILabel width based on text length?

CGSize expectedLabelSize = [yourString sizeWithFont:yourLabel.font 
                        constrainedToSize:maximumLabelSize 
                        lineBreakMode:yourLabel.lineBreakMode]; 

What is -[NSString sizeWithFont:forWidth:lineBreakMode:] good for?

this question might have your answer, it worked for me.


For 2014, I edited in this new version, based on the ultra-handy comment by Norbert below! This does everything. Cheers

// yourLabel is your UILabel.

float widthIs = 
 [self.yourLabel.text
  boundingRectWithSize:self.yourLabel.frame.size                                           
  options:NSStringDrawingUsesLineFragmentOrigin
  attributes:@{ NSFontAttributeName:self.yourLabel.font }
  context:nil]
   .size.width;

NSLog(@"the width of yourLabel is %f", widthIs);

Setting a PHP $_SESSION['var'] using jQuery

I also designed a "php session value setter" solution by myself (similar to Luke Dennis' solution. No big deal here), but after setting my session value, my needs were "jumping onto another .php file". Ok, I did it, inside my jquery code... But something didn't quite work...

My problem was kind of easy:

-After you "$.post" your values onto the small .php file, you should wait for some "success/failure" return value, and ONLY AFTER READING THIS SUCCESS VALUE, perform the jump. If you just immediately jump onto the next big .php file, your session value might have not become set onto the php sessions runtime engine, and will you probably read "empty" when doing $_SESSION["my_var"]; from the destination .php file.

In my case, to correct that situation, I changed my jQuery $.post code this way:

$.post('set_session_value.php', { key: 'keyname', value: 'myvalue'}, function(ret){
    if(ret==0){
        window.alert("success!");
        location.replace("next_page.php");
    }
    else{
        window.alert("error!");
    }
});

Of course, your "set_session_value.php" file, should return 'echo "0"; ' or 'echo "1"; ' (or whatever success values you might need).

Greetings.

How to add a “readonly” attribute to an <input>?

Use the setAttribute property. Note in example that if select 1 apply the readonly attribute on textbox, otherwise remove the attribute readonly.

http://jsfiddle.net/baqxz7ym/2/

document.getElementById("box1").onchange = function(){
  if(document.getElementById("box1").value == 1) {
    document.getElementById("codigo").setAttribute("readonly", true);
  } else {
    document.getElementById("codigo").removeAttribute("readonly");
  }
};

<input type="text" name="codigo" id="codigo"/>

<select id="box1">
<option value="0" >0</option>
<option value="1" >1</option>
<option value="2" >2</option>
</select>

Fatal error: Class 'SoapClient' not found

For XAMPP users, open php.ini file located in C:/xampp/php and remove the ; from the beginning of extension=soap. Then restart Apache and that's it!

Entity Framework is Too Slow. What are my options?

I have found the answer by @Slauma here very useful for speeding things up. I used the same sort of pattern for both inserts and updates - and performance rocketed.

Confirm postback OnClientClick button ASP.NET

This is a simple way to do client-side validation BEFORE the confirmation. It makes use of the built in ASP.NET validation javascript.

<script type="text/javascript">
    function validateAndConfirm() {
        Page_ClientValidate("GroupName");  //'GroupName' is the ValidationGroup
        if (Page_IsValid) {
            return confirm("Are you sure?");
        }
        return false;
    }
</script>

<asp:TextBox ID="IntegerTextBox" runat="server" Width="100px" MaxLength="6" />
<asp:RequiredFieldValidator ID="reqIntegerTextBox" runat="server" ErrorMessage="Required"
    ValidationGroup="GroupName"  ControlToValidate="IntegerTextBox" />
<asp:RangeValidator ID="rangeTextBox" runat="server" ErrorMessage="Invalid"
    ValidationGroup="GroupName" Type="Integer" ControlToValidate="IntegerTextBox" />
<asp:Button ID="SubmitButton" runat="server" Text="Submit"  ValidationGroup="GroupName"
    OnClick="SubmitButton_OnClick" OnClientClick="return validateAndConfirm();" />

Source: Client Side Validation using ASP.Net Validator Controls from Javascript

Auto generate function documentation in Visual Studio

Make that "three single comment-markers"

In C# it's ///

which as default spits out:

/// <summary>
/// 
/// </summary>
/// <returns></returns>

Here's some tips on editing VS templates.

How to prevent Screen Capture in Android

Just add this line:

getWindow().setFlags(LayoutParams.FLAG_SECURE, LayoutParams.FLAG_SECURE);

Before your setContentView() method.

Text-decoration: none not working

if you want a nav bar do

ul{ list-style-type: none; } li{text-decoration: none;
  • This will make it want to make the style of the list type to None or nothing

with the < a > tag:

a:link {text-decoration: none}

What is a Subclass

It is a class that extends another class.

example taken from https://www.java-tips.org/java-se-tips-100019/24-java-lang/784-what-is-a-java-subclass.html, Cat is a sub class of Animal :-)

public class Animal {

    public static void hide() {
        System.out.println("The hide method in Animal.");
    }

    public void override() {
        System.out.println("The override method in Animal.");
    }
}

public class Cat extends Animal {

    public static void hide() {
        System.out.println("The hide method in Cat.");
    }

    public void override() {
        System.out.println("The override method in Cat.");
    }

    public static void main(String[] args) {
        Cat myCat = new Cat();
        Animal myAnimal = (Animal)myCat;
        myAnimal.hide();
        myAnimal.override();
    }
}

Equivalent VB keyword for 'break'

In case you're inside a Sub of Function and you want to exit it, you can use :

Exit Sub

or

Exit Function 

Checking session if empty or not

You need to check that Session["emp_num"] is not null before trying to convert it to a string otherwise you will get a null reference exception.

I'd go with your first example - but you could make it slightly more "elegant".

There are a couple of ways, but the ones that springs to mind are:

if (Session["emp_num"] is string)
{
}

or

if (!string.IsNullOrEmpty(Session["emp_num"] as string))
{
}

This will return null if the variable doesn't exist or isn't a string.

How to convert upper case letters to lower case

You can find more methods and functions related to Python strings in section 5.6.1. String Methods of the documentation.

w.strip(',.').lower()

BeautifulSoup getText from between <p>, not picking up subsequent paragraphs

You are getting close!

# Find all of the text between paragraph tags and strip out the html
page = soup.find('p').getText()

Using find (as you've noticed) stops after finding one result. You need find_all if you want all the paragraphs. If the pages are formatted consistently ( just looked over one), you could also use something like

soup.find('div',{'id':'ctl00_PlaceHolderMain_RichHtmlField1__ControlWrapper_RichHtmlField'})

to zero in on the body of the article.

Select rows having 2 columns equal value

Actually this would go faster in most of cases:

SELECT *
FROM table ta1
JOIN table ta2 on ta1.id != ta2.id
WHERE ta1.c2 = ta2.c2 and ta1.c3 = ta2.c3 and ta1.c4 = ta2.c4

You join on different rows which have the same values. I think it should work. Correct me if I'm wrong.

Where can I download Spring Framework jars without using Maven?

Please edit to keep this list of mirrors current

I found this maven repo where you could download from directly a zip file containing all the jars you need.

Alternate solution: Maven

The solution I prefer is using Maven, it is easy and you don't have to download each jar alone. You can do it with the following steps:

  1. Create an empty folder anywhere with any name you prefer, for example spring-source

  2. Create a new file named pom.xml

  3. Copy the xml below into this file

  4. Open the spring-source folder in your console

  5. Run mvn install

  6. After download finished, you'll find spring jars in /spring-source/target/dependencies

    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <groupId>spring-source-download</groupId>
      <artifactId>SpringDependencies</artifactId>
      <version>1.0</version>
      <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
      </properties>
      <dependencies>
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-context</artifactId>
          <version>3.2.4.RELEASE</version>
        </dependency>
      </dependencies>
      <build>
        <plugins>
          <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-dependency-plugin</artifactId>
            <version>2.8</version>
            <executions>
              <execution>
                <id>download-dependencies</id>
                <phase>generate-resources</phase>
                <goals>
                  <goal>copy-dependencies</goal>
                </goals>
                <configuration>
                  <outputDirectory>${project.build.directory}/dependencies</outputDirectory>
                </configuration>
              </execution>
            </executions>
          </plugin>
        </plugins>
      </build>
    </project>
    

Also, if you need to download any other spring project, just copy the dependency configuration from its corresponding web page.

For example, if you want to download Spring Web Flow jars, go to its web page, and add its dependency configuration to the pom.xml dependencies, then run mvn install again.

<dependency>
  <groupId>org.springframework.webflow</groupId>
  <artifactId>spring-webflow</artifactId>
  <version>2.3.2.RELEASE</version>
</dependency>

Returning boolean if set is empty

If you want to return True for an empty set, then I think it would be clearer to do:

return c == set()

i.e. "c is equal to an empty set".

(Or, for the other way around, return c != set()).

In my opinion, this is more explicit (though less idiomatic) than relying on Python's interpretation of an empty set as False in a boolean context.

Java default constructor

Java provides a default constructor which takes no arguments and performs no special actions or initializations, when no explicit constructors are provided.

The only action taken by the implicit default constructor is to call the superclass constructor using the super() call. Constructor arguments provide you with a way to provide parameters for the initialization of an object.

Below is an example of a cube class containing 2 constructors. (one default and one parameterized constructor).

public class Cube1 {
    int length;
    int breadth;
    int height;
    public int getVolume() {
        return (length * breadth * height);
    }

    Cube1() {
        length = 10;
        breadth = 10;
        height = 10;
    }

    Cube1(int l, int b, int h) {
        length = l;
        breadth = b;
        height = h;
    }

    public static void main(String[] args) {
        Cube1 cubeObj1, cubeObj2;
        cubeObj1 = new Cube1();
        cubeObj2 = new Cube1(10, 20, 30);
        System.out.println("Volume of Cube1 is : " + cubeObj1.getVolume());
        System.out.println("Volume of Cube1 is : " + cubeObj2.getVolume());
    }
}

Quickly create large file on a Windows system

... 1 MB file dummy.txt within few seconds.

echo "This is just a sample line appended to create a big file.. " > dummy.txt for /L %i in (1,1,14) do type dummy.txt >> dummy.txt

See here : http://www.windows-commandline.com/how-to-create-large-dummy-file/

java.lang.OutOfMemoryError: Java heap space

  1. In most of the cases, the code is not optimized. Release those objects which you think shall not be needed further. Avoid creation of objects in your loop each time. Try to use caches. I don't know how your application is doing. But In programming, one rule of normal life applies as well

    Prevention is better than cure. "Don't create unnecessary objects"

ImportError: No module named request

from @Zzmilanzz's answer I used

try: #python3
    from urllib.request import urlopen
except: #python2
    from urllib2 import urlopen

Bootstrap Responsive Text Size

Simplest way is to use dimensions in % or em. Just change the base font size everything will change.

Less

@media (max-width: @screen-xs) {
    body{font-size: 10px;}
}

@media (max-width: @screen-sm) {
    body{font-size: 14px;}
}


h5{
    font-size: 1.4rem;
}       

Look at all the ways at https://stackoverflow.com/a/21981859/406659

You could use viewport units (vh,vw...) but they dont work on Android < 4.4

How to change the color of a button?

Through Programming:

btn.setBackgroundColor(getResources().getColor(R.color.colorOffWhite));

and your colors.xml must contain...

<?xml version="1.0" encoding="utf-8"?>
<resources>
 <color name="colorOffWhite">#80ffffff</color>
</resources>

AngularJS : When to use service instead of factory

Services

Syntax: module.service( 'serviceName', function ); Result: When declaring serviceName as an injectable argument you will be provided the actual function reference passed to module.service.

Usage: Could be useful for sharing utility functions that are useful to invoke by simply appending () to the injected function reference. Could also be run with injectedArg.call( this ) or similar.

Factories

Syntax: module.factory( 'factoryName', function );

Result: When declaring factoryName as an injectable argument you will be provided the value that is returned by invoking the function reference passed to module.factory.

Usage: Could be useful for returning a 'class' function that can then be new'ed to create instances.

Providers

Syntax: module.provider( 'providerName', function );

Result: When declaring providerName as an injectable argument you will be provided the value that is returned by invoking the $get method of the function reference passed to module.provider.

Usage: Could be useful for returning a 'class' function that can then be new'ed to create instances but that requires some sort of configuration before being injected. Perhaps useful for classes that are reusable across projects? Still kind of hazy on this one.

Brew install docker does not include docker engine?

The following steps work fine on macOS Sierra 10.12.4. Note that after brew installs Docker, the docker command (symbolic link) is not available at /usr/local/bin. Running the Docker app for the first time creates this symbolic link. See the detailed steps below.

  1. Install Docker.

    brew cask install docker
    
  2. Launch Docker.

    • Press ? + Space to bring up Spotlight Search and enter Docker to launch Docker.
    • In the Docker needs privileged access dialog box, click OK.
    • Enter password and click OK.

    When Docker is launched in this manner, a Docker whale icon appears in the status menu. As soon as the whale icon appears, the symbolic links for docker, docker-compose, docker-credential-osxkeychain and docker-machine are created in /usr/local/bin.

    $ ls -l /usr/local/bin/docker*
    lrwxr-xr-x  1 susam  domain Users  67 Apr 12 14:14 /usr/local/bin/docker -> /Users/susam/Library/Group Containers/group.com.docker/bin/docker
    lrwxr-xr-x  1 susam  domain Users  75 Apr 12 14:14 /usr/local/bin/docker-compose -> /Users/susam/Library/Group Containers/group.com.docker/bin/docker-compose
    lrwxr-xr-x  1 susam  domain Users  90 Apr 12 14:14 /usr/local/bin/docker-credential-osxkeychain -> /Users/susam/Library/Group Containers/group.com.docker/bin/docker-credential-osxkeychain
    lrwxr-xr-x  1 susam  domain Users  75 Apr 12 14:14 /usr/local/bin/docker-machine -> /Users/susam/Library/Group Containers/group.com.docker/bin/docker-machine
    
  3. Click on the docker whale icon in the status menu and wait for it to show Docker is running.

    enter image description here enter image description here

  4. Test that docker works fine.

    $ docker run hello-world
    Unable to find image 'hello-world:latest' locally
    latest: Pulling from library/hello-world
    78445dd45222: Pull complete
    Digest: sha256:c5515758d4c5e1e838e9cd307f6c6a0d620b5e07e6f927b07d05f6d12a1ac8d7
    Status: Downloaded newer image for hello-world:latest
    
    Hello from Docker!
    This message shows that your installation appears to be working correctly.
    
    To generate this message, Docker took the following steps:
     1. The Docker client contacted the Docker daemon.
     2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
     3. The Docker daemon created a new container from that image which runs the
        executable that produces the output you are currently reading.
     4. The Docker daemon streamed that output to the Docker client, which sent it
        to your terminal.
    
    To try something more ambitious, you can run an Ubuntu container with:
     $ docker run -it ubuntu bash
    
    Share images, automate workflows, and more with a free Docker ID:
     https://cloud.docker.com/
    
    For more examples and ideas, visit:
     https://docs.docker.com/engine/userguide/
    
    $ docker version
    Client:
     Version:      17.03.1-ce
     API version:  1.27
     Go version:   go1.7.5
     Git commit:   c6d412e
     Built:        Tue Mar 28 00:40:02 2017
     OS/Arch:      darwin/amd64
    
    Server:
     Version:      17.03.1-ce
     API version:  1.27 (minimum version 1.12)
     Go version:   go1.7.5
     Git commit:   c6d412e
     Built:        Fri Mar 24 00:00:50 2017
     OS/Arch:      linux/amd64
     Experimental: true
    
  5. If you are going to use docker-machine to create virtual machines, install VirtualBox.

    brew cask install virtualbox
    

    Note that if VirtualBox is not installed, then docker-machine fails with the following error.

    $ docker-machine create manager
    Running pre-create checks...
    Error with pre-create check: "VBoxManage not found. Make sure VirtualBox is installed and VBoxManage is in the path"
    

Spring,Request method 'POST' not supported

You are missimg @ModelAttribute annotation for UserProfessionalForm professionalForm parameter in forgotPassword method.

@RequestMapping(value = "proffessional", method = RequestMethod.POST)
public @ResponseBody
String forgotPassword(@ModelAttribute UserProfessionalForm professionalForm,
        BindingResult result, Model model) {

    UserProfileVO userProfileVO = new UserProfileVO();
    userProfileVO.setUser(sessionData.getUser());
    userService.saveUserProfile(userProfileVO);
    model.addAttribute("professional", professionalForm);
    return "Your Professional Details Updated";
}

How to add column to numpy array

I think that your problem is that you are expecting np.append to add the column in-place, but what it does, because of how numpy data is stored, is create a copy of the joined arrays

Returns
-------
append : ndarray
    A copy of `arr` with `values` appended to `axis`.  Note that `append`
    does not occur in-place: a new array is allocated and filled.  If
    `axis` is None, `out` is a flattened array.

so you need to save the output all_data = np.append(...):

my_data = np.random.random((210,8)) #recfromcsv('LIAB.ST.csv', delimiter='\t')
new_col = my_data.sum(1)[...,None] # None keeps (n, 1) shape
new_col.shape
#(210,1)
all_data = np.append(my_data, new_col, 1)
all_data.shape
#(210,9)

Alternative ways:

all_data = np.hstack((my_data, new_col))
#or
all_data = np.concatenate((my_data, new_col), 1)

I believe that the only difference between these three functions (as well as np.vstack) are their default behaviors for when axis is unspecified:

  • concatenate assumes axis = 0
  • hstack assumes axis = 1 unless inputs are 1d, then axis = 0
  • vstack assumes axis = 0 after adding an axis if inputs are 1d
  • append flattens array

Based on your comment, and looking more closely at your example code, I now believe that what you are probably looking to do is add a field to a record array. You imported both genfromtxt which returns a structured array and recfromcsv which returns the subtly different record array (recarray). You used the recfromcsv so right now my_data is actually a recarray, which means that most likely my_data.shape = (210,) since recarrays are 1d arrays of records, where each record is a tuple with the given dtype.

So you could try this:

import numpy as np
from numpy.lib.recfunctions import append_fields
x = np.random.random(10)
y = np.random.random(10)
z = np.random.random(10)
data = np.array( list(zip(x,y,z)), dtype=[('x',float),('y',float),('z',float)])
data = np.recarray(data.shape, data.dtype, buf=data)
data.shape
#(10,)
tot = data['x'] + data['y'] + data['z'] # sum(axis=1) won't work on recarray
tot.shape
#(10,)
all_data = append_fields(data, 'total', tot, usemask=False)
all_data
#array([(0.4374783740738456 , 0.04307289878861764, 0.021176067323686598, 0.5017273401861498),
#       (0.07622262416466963, 0.3962146058689695 , 0.27912715826653534 , 0.7515643883001745),
#       (0.30878532523061153, 0.8553768789387086 , 0.9577415585116588  , 2.121903762680979 ),
#       (0.5288343561208022 , 0.17048864443625933, 0.07915689716226904 , 0.7784798977193306),
#       (0.8804269791375121 , 0.45517504750917714, 0.1601389248542675  , 1.4957409515009568),
#       (0.9556552723429782 , 0.8884504475901043 , 0.6412854758843308  , 2.4853911958174133),
#       (0.0227638618687922 , 0.9295332854783015 , 0.3234597575660103  , 1.275756904913104 ),
#       (0.684075052174589  , 0.6654774682866273 , 0.5246593820025259  , 1.8742119024637423),
#       (0.9841793718333871 , 0.5813955915551511 , 0.39577520705133684 , 1.961350170439875 ),
#       (0.9889343795296571 , 0.22830104497714432, 0.20011292764078448 , 1.4173483521475858)], 
#      dtype=[('x', '<f8'), ('y', '<f8'), ('z', '<f8'), ('total', '<f8')])
all_data.shape
#(10,)
all_data.dtype.names
#('x', 'y', 'z', 'total')

Getting only Month and Year from SQL DATE

Query :- Select datename(m,GETDATE())+'-'+cast(datepart(yyyy,GETDATE()) as varchar) as FieldName

Output :- January-2019

general datefield we can use

datename(m,<DateField>)+' '+cast(datepart(yyyy,<DateField>) as varchar) as FieldName

Retrieve specific commit from a remote Git repository

I think 'git ls-remote' ( http://git-scm.com/docs/git-ls-remote ) should do what you want. Without force fetch or pull.

Using Node.js require vs. ES6 import/export

Not sure why (probably optimization - lazy loading?) is it working like that, but I have noticed that import may not parse code if imported modules are not used.
Which may not be expected behaviour in some cases.

Take hated Foo class as our sample dependency.

foo.ts

export default class Foo {}
console.log('Foo loaded');

For example:

index.ts

import Foo from './foo'
// prints nothing

index.ts

const Foo = require('./foo').default;
// prints "Foo loaded"

index.ts

(async () => {
    const FooPack = await import('./foo');
    // prints "Foo loaded"
})();

On the other hand:

index.ts

import Foo from './foo'
typeof Foo; // any use case
// prints "Foo loaded"

Direct download from Google Drive using Google Drive API

https://github.com/google/skicka

I used this command line tool to download files from Google Drive. Just follow the instructions in Getting Started section and you should download files from Google Drive in minutes.

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

I found that this works really well in Chrome.

Right click on the element that you'd like to inspect, then click Force Element State > Hover. Screenshot attached.

Force element state

npm ERR! network getaddrinfo ENOTFOUND

Instead of setting the proxy usingnpm config set http_proxy=http://address:8080 go to ~/.npmrc and remove the proxy config. This resolved my issue.

Get exit code of a background process

Another solution is to monitor processes via the proc filesystem (safer than ps/grep combo); when you start a process it has a corresponding folder in /proc/$pid, so the solution could be

#!/bin/bash
....
doSomething &
local pid=$!
while [ -d /proc/$pid ]; do # While directory exists, the process is running
    doSomethingElse
    ....
else # when directory is removed from /proc, process has ended
    wait $pid
    local exit_status=$?
done
....

Now you can use the $exit_status variable however you like.

How to use session in JSP pages to get information?

JSP implicit objects likes session, request etc. are not available inside JSP declaration <%! %> tags.

You could use it directly in your expression as

<td>Username: </td>
<td><input type="text" value="<%= session.getAttribute("username") %>" /></td>

On other note, using scriptlets in JSP has been long deprecated. Use of EL (expression language) and JSTL tags is highly recommended. For example, here you could use EL as

<td>Username: </td>
<td><input type="text" value="${username}" /></td>

The best part is that scope resolution is done automatically. So, here username could come from page, or request, or session, or application scopes in that order. If for a particular instance you need to override this because of a name collision you can explicitly specify the scope as

<td><input type="text" value="${requestScope.username}" /></td> or,
<td><input type="text" value="${sessionScope.username}" /></td> or,
<td><input type="text" value="${applicationScope.username}" /></td>

sed: print only matching group

And for yet another option, I'd go with awk!

echo "foo bar <foo> bla 1 2 3.4" | awk '{ print $(NF-1), $NF; }'

This will split the input (I'm using STDIN here, but your input could easily be a file) on spaces, and then print out the last-but-one field, and then the last field. The $NF variables hold the number of fields found after exploding on spaces.

The benefit of this is that it doesn't matter if what precedes the last two fields changes, as long as you only ever want the last two it'll continue to work.

jQuery send HTML data through POST

I don't see why you shouldn't be able to send html content via a post.

if you encounter any issues, you could perhaps use some kind of encoding / decoding - but I don't see that you will.

Python class input argument

How about this?


class name(str):
    def __init__(self, name):
        print (name)
# ------
person1 = name("jean")
person2 = name("dean")
print('===')
print(person1)
print(person2)

Output:

jean
dean
===
jean
dean

Can't bind to 'dataSource' since it isn't a known property of 'table'

Thanx to @Jota.Toledo, I got the solution for my table creation. Please find the working code below:

component.html

<mat-table #table [dataSource]="dataSource" matSort>
  <ng-container matColumnDef="{{column.id}}" *ngFor="let column of columnNames">
    <mat-header-cell *matHeaderCellDef mat-sort-header> {{column.value}}</mat-header-cell>
    <mat-cell *matCellDef="let element"> {{element[column.id]}}</mat-cell>
  </ng-container>

  <mat-header-row *matHeaderRowDef="displayedColumns"></mat-header-row>
  <mat-row *matRowDef="let row; columns: displayedColumns;"></mat-row>
</mat-table>

component.ts

import { Component, OnInit, ViewChild } from '@angular/core';
import { MatTableDataSource, MatSort } from '@angular/material';
import { DataSource } from '@angular/cdk/table';

@Component({
  selector: 'app-m',
  templateUrl: './m.component.html',
  styleUrls: ['./m.component.css'],
})
export class MComponent implements OnInit {

  dataSource;
  displayedColumns = [];
  @ViewChild(MatSort) sort: MatSort;

  /**
   * Pre-defined columns list for user table
   */
  columnNames = [{
    id: 'position',
    value: 'No.',

  }, {
    id: 'name',
    value: 'Name',
  },
    {
      id: 'weight',
      value: 'Weight',
    },
    {
      id: 'symbol',
      value: 'Symbol',
    }];

  ngOnInit() {
    this.displayedColumns = this.columnNames.map(x => x.id);
    this.createTable();
  }

  createTable() {
    let tableArr: Element[] = [{ position: 1, name: 'Hydrogen', weight: 1.0079, symbol: 'H' },
      { position: 2, name: 'Helium', weight: 4.0026, symbol: 'He' },
      { position: 3, name: 'Lithium', weight: 6.941, symbol: 'Li' },
      { position: 4, name: 'Beryllium', weight: 9.0122, symbol: 'Be' },
      { position: 5, name: 'Boron', weight: 10.811, symbol: 'B' },
      { position: 6, name: 'Carbon', weight: 12.0107, symbol: 'C' },
    ];
    this.dataSource = new MatTableDataSource(tableArr);
    this.dataSource.sort = this.sort;
  }
}

export interface Element {
  position: number,
  name: string,
  weight: number,
  symbol: string
}

app.module.ts

imports: [
  MatSortModule,
  MatTableModule,
],

Using continue in a switch statement

This might be a megabit to late but you can use continue 2.

Some php builds / configs will output this warning:

PHP Warning: "continue" targeting switch is equivalent to "break". Did you mean to use "continue 2"?

For example:

$i = 1;

while ($i <= 10) {
    $mod = $i % 4;
    echo "\r\n out $i";
    $i++;
    switch($mod)
    {
        case 0:
            break;
        case 2:
            continue;
            break;
        default:
            continue 2;
            break;
    }
    echo " is even";
}

This will output:

out 1
out 2 is even
out 3
out 4 is even
out 5
out 6 is even
out 7
out 8 is even
out 9
out 10 is even

Tested with PHP 5.5 and higher.

Random float number generation

Take a look at Boost.Random. You could do something like this:

float gen_random_float(float min, float max)
{
    boost::mt19937 rng;
    boost::uniform_real<float> u(min, max);
    boost::variate_generator<boost::mt19937&, boost::uniform_real<float> > gen(rng, u);
    return gen();
}

Play around, you might do better passing the same mt19937 object around instead of constructing a new one every time, but hopefully you get the idea.

Better way to Format Currency Input editText?

After looking at most of the StackOverflow posts on different ways to achieve this using a TextWatcher, InputFilter, or library like CurrencyEditText I've settled on this simple solution using an OnFocusChangeListener.

The logic is to parse the EditText to a number when it is focused and to format it back when it loses focus.

amount.setOnFocusChangeListener(new View.OnFocusChangeListener() {
        @Override
        public void onFocusChange(View view, boolean hasFocus) {
            Number numberAmount = 0f;
            try {
                numberAmount = Float.valueOf(amount.getText().toString());
            } catch (NumberFormatException e1) {
                e1.printStackTrace();
                try {
                    numberAmount = NumberFormat.getCurrencyInstance().parse(amount.getText().toString());
                } catch (ParseException e2) {
                    e2.printStackTrace();
                }
            }
            if (hasFocus) {
                amount.setText(numberAmount.toString());
            } else {
                amount.setText(NumberFormat.getCurrencyInstance().format(numberAmount));
            }
        }
    });

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

OID's are still in use for Postgres with large objects (though some people would argue large objects are not generally useful anyway). They are also used extensively by system tables. They are used for instance by TOAST which stores larger than 8KB BYTEA's (etc.) off to a separate storage area (transparently) which is used by default by all tables. Their direct use associated with "normal" user tables is basically deprecated.

The oid type is currently implemented as an unsigned four-byte integer. Therefore, it is not large enough to provide database-wide uniqueness in large databases, or even in large individual tables. So, using a user-created table's OID column as a primary key is discouraged. OIDs are best used only for references to system tables.

Apparently the OID sequence "does" wrap if it exceeds 4B 6. So in essence it's a global counter that can wrap. If it does wrap, some slowdown may start occurring when it's used and "searched" for unique values, etc.

See also https://wiki.postgresql.org/wiki/FAQ#What_is_an_OID.3F

How to to send mail using gmail in Laravel?

Using a G Suite account

If you are using a G Suite account, anything you try will fail. At least at the time, this answer is being typed. You must use @gmail.com account, anything else like @example.com will not work.

After you use the gmail.com address. You just need to update .env as most of the people already mentioned.

MAIL_MAILER=smtp
MAIL_HOST=smtp.gmail.com
MAIL_PORT=587
MAIL_USERNAME=****@gmail.com
MAIL_PASSWORD=16digitapppassword
MAIL_ENCRYPTION=tls
MAIL_FROM_ADDRESS=****@gmail.com
MAIL_FROM_NAME="${APP_NAME}"

Don't forget to create an App password, if you don't see the option probably your 2-factor authentication is not enabled. And there is no need to allow less secure apps if you follow this approach.

How do I find the install time and date of Windows?

Very simple way from PowerShell:

(Get-CimInstance -Class Win32_OperatingSystem).InstallDate

Extracted from: https://www.sysadmit.com/2019/10/windows-cuando-fue-instalado.html

How can I mock an ES6 module import using Jest?

I've been able to solve this by using a hack involving import *. It even works for both named and default exports!

For a named export:

// dependency.js
export const doSomething = (y) => console.log(y)

// myModule.js
import { doSomething } from './dependency';

export default (x) => {
  doSomething(x * 2);
}

// myModule-test.js
import myModule from '../myModule';
import * as dependency from '../dependency';

describe('myModule', () => {
  it('calls the dependency with double the input', () => {
    dependency.doSomething = jest.fn(); // Mutate the named export

    myModule(2);

    expect(dependency.doSomething).toBeCalledWith(4);
  });
});

Or for a default export:

// dependency.js
export default (y) => console.log(y)

// myModule.js
import dependency from './dependency'; // Note lack of curlies

export default (x) => {
  dependency(x * 2);
}

// myModule-test.js
import myModule from '../myModule';
import * as dependency from '../dependency';

describe('myModule', () => {
  it('calls the dependency with double the input', () => {
    dependency.default = jest.fn(); // Mutate the default export

    myModule(2);

    expect(dependency.default).toBeCalledWith(4); // Assert against the default
  });
});

As Mihai Damian quite rightly pointed out below, this is mutating the module object of dependency, and so it will 'leak' across to other tests. So if you use this approach you should store the original value and then set it back again after each test.

To do this easily with Jest, use the spyOn() method instead of jest.fn(), because it supports easily restoring its original value, therefore avoiding before mentioned 'leaking'.

Moment JS - check if a date is today or in the future

Update

moment().isSame('2010-02-01', 'day'); // Return true if we are the 2010-02-01

I have since found the isSame function, which in I believe is the correct function to use for figuring out if a date is today.

Original answer

Just in case someone else needs this, just do this:

const isToday = moment(0, "HH").diff(date, "days") == 0;

or if you want a function:

isToday = date => moment(0,"HH").diff(date, "days") == 0;

Where date is the date you want to check for.

Explanation

moment(0, "HH") returns today's day at midnight.

date1.diff(date2, "days") returns the number of days between the date1 and date2.

How to represent a DateTime in Excel

dd-mm-yyyy hh:mm:ss.000 Universal sortable date/time pattern

Adding an onclick function to go to url in JavaScript?

If you would like to open link in a new tab, you can:

$("a#thing_to_click").on('click',function(){
    window.open('https://yoururl.com', '_blank');
});

ThreadStart with parameters

class Program
{
    static void Main(string[] args)
    {
        Thread t = new Thread(new ParameterizedThreadStart(ThreadMethod));

        t.Start("My Parameter");
    }

    static void ThreadMethod(object parameter)
    {
        // parameter equals to "My Parameter"
    }
}

The application may be doing too much work on its main thread

I had the same problem. Android Emulator worked perfectly on Android < 6.0. When I used emulator Nexus 5 (Android 6.0), the app worked very slow with I/Choreographer: Skipped frames in the logs.

So, I solved this problem by changing in Manifest file hardwareAccelerated option to true like this:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.myapplication">

    <application android:hardwareAccelerated="true">
        ...
    </application>
</manifest>

Jquery: how to trigger click event on pressing enter key

$('#txtSearchProdAssign').keypress(function (e) {
  if (e.which == 13) {
    $('input[name = butAssignProd]').click();
    return false;  
  }
});

I also just found Submitting a form on 'Enter' which covers most of the issues comprehensively.

Remove characters before character "."

A couple of methods that, if the char does not exists, return the original string.

This one cuts the string after the first occurrence of the pivot:

public static string truncateStringAfterChar(string input, char pivot){         
    int index = input.IndexOf(pivot);   
    if(index >= 0) {
        return input.Substring(index + 1);          
    }           
    return input;       
}

This one instead cuts the string after the last occurrence of the pivot:

public static string truncateStringAfterLastChar(string input, char pivot){         
    return input.Split(pivot).Last();   
}

Is it possible in Java to access private fields via reflection

Yes.

  Field f = Test.class.getDeclaredField("str");
  f.setAccessible(true);//Very important, this allows the setting to work.
  String value = (String) f.get(object);

Then you use the field object to get the value on an instance of the class.

Note that get method is often confusing for people. You have the field, but you don't have an instance of the object. You have to pass that to the get method

How can I alter a primary key constraint using SQL syntax?

you can rename constraint objects using sp_rename (as described in this answer)

for example:

EXEC sp_rename N'schema.MyIOldConstraint', N'MyNewConstraint'

php implode (101) with quotes

$array = array('lastname', 'email', 'phone');


echo "'" . implode("','", $array) . "'";

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'demoRestController'

Your DemoApplication class is in the com.ag.digital.demo.boot package and your LoginBean class is in the com.ag.digital.demo.bean package. By default components (classes annotated with @Component) are found if they are in the same package or a sub-package of your main application class DemoApplication. This means that LoginBean isn't being found so dependency injection fails.

There are a couple of ways to solve your problem:

  1. Move LoginBean into com.ag.digital.demo.boot or a sub-package.
  2. Configure the packages that are scanned for components using the scanBasePackages attribute of @SpringBootApplication that should be on DemoApplication.

A few of other things that aren't causing a problem, but are not quite right with the code you've posted:

  • @Service is a specialisation of @Component so you don't need both on LoginBean
  • Similarly, @RestController is a specialisation of @Component so you don't need both on DemoRestController
  • DemoRestController is an unusual place for @EnableAutoConfiguration. That annotation is typically found on your main application class (DemoApplication) either directly or via @SpringBootApplication which is a combination of @ComponentScan, @Configuration, and @EnableAutoConfiguration.

deny directory listing with htaccess

Options -Indexes returns a 403 forbidden error for a protected directory. The same behaviour can be achived by using the following Redirect in htaccess :

RedirectMatch 403 ^/folder/?$ 

This will return a forbidden error for example.com/folder/ .

You can also use mod-rewrite to forbid a request for folder.

RewriteEngine on

RewriteRule ^folder/?$ - [F]

If your htaccess is in the folder that you are going to forbid , change RewriteRule's pattern from ^folder/?$ to ^$ .

Highlight a word with jQuery

You need to get the content of the p tag and replace all the dolors in it with the highlighted version.

You don't even need to have jQuery for this. :-)

Circular (or cyclic) imports in Python

I completely agree with pythoneer's answer here. But I have stumbled on some code that was flawed with circular imports and caused issues when trying to add unit tests. So to quickly patch it without changing everything you can resolve the issue by doing a dynamic import.

# Hack to import something without circular import issue
def load_module(name):
    """Load module using imp.find_module"""
    names = name.split(".")
    path = None
    for name in names:
        f, path, info = imp.find_module(name, path)
        path = [path]
    return imp.load_module(name, f, path[0], info)
constants = load_module("app.constants")

Again, this isn't a permanent fix but may help someone that wants to fix an import error without changing too much of the code.

Cheers!

How to compare arrays in C#?

You're comparing the object references, and they are not the same. You need to compare the array contents.

.NET2 solution

An option is iterating through the array elements and call Equals() for each element. Remember that you need to override the Equals() method for the array elements, if they are not the same object reference.

An alternative is using this generic method to compare two generic arrays:

static bool ArraysEqual<T>(T[] a1, T[] a2)
{
    if (ReferenceEquals(a1, a2))
        return true;

    if (a1 == null || a2 == null)
        return false;

    if (a1.Length != a2.Length)
        return false;

    var comparer = EqualityComparer<T>.Default;
    for (int i = 0; i < a1.Length; i++)
    {
        if (!comparer.Equals(a1[i], a2[i])) return false;
    }
    return true;
}

.NET 3.5 or higher solution

Or use SequenceEqual if Linq is available for you (.NET Framework >= 3.5)

Apache 13 permission denied in user's home directory

Turns out... we had to also chmod 755 the parent directory, user, in addition to xxx.

How to get row data by clicking a button in a row in an ASP.NET gridview

 protected void btnS10_click(object sender, EventArgs e)
    {
        foreach (GridViewRow row in Grd.Rows)
        {
            CheckBox chk_Single = (CheckBox)row.FindControl("ChkSendOne");
            if (row.RowType == DataControlRowType.DataRow)
            {
                string id = (row.Cells[0].FindControl("lblSNo") as Label).Text;
                if (Convert.ToInt32(id) <= 10)
                {
                   
                    chk_Single.Checked = true;
                    if (chk_Single.Checked == true)
                    {
                        lblSelectedRecord.InnerText = (Convert.ToInt32(lblSelectedRecord.InnerText) + 1).ToString();
                    }
                }
            }
        }
    }

Comparing date part only without comparing time in JavaScript

After reading this question quite same time after it is posted I have decided to post another solution, as I didn't find it that quite satisfactory, at least to my needs:

I have used something like this:

var currentDate= new Date().setHours(0,0,0,0);

var startDay = new Date(currentDate - 86400000 * 2);
var finalDay = new Date(currentDate + 86400000 * 2);

In that way I could have used the dates in the format I wanted for processing afterwards. But this was only for my need, but I have decided to post it anyway, maybe it will help someone

Spring JPA selecting specific columns

It is possible to specify null as field value in native sql.

@Query(value = "select p.id, p.uid, p.title, null as documentation, p.ptype " +
            " from projects p " +
            "where p.uid = (:uid)" +
            "  and p.ptype = 'P'", nativeQuery = true)
Project findInfoByUid(@Param("uid") String uid);

What's a .sh file?

What is a file with extension .sh?

It is a Bourne shell script. They are used in many variations of UNIX-like operating systems. They have no "language" and are interpreted by your shell (interpreter of terminal commands) or if the first line is in the form

#!/path/to/interpreter

they will use that particular interpreter. Your file has the first line:

#!/bin/bash

and that means that it uses Bourne Again Shell, so called bash. It is for all practical purposes a replacement for good old sh.

Depending upon the interpreter you will have different language in which the file is written.

Keep in mind, that in UNIX world, it is not the extension of the file that determines what the file is (see How to execute a shell script).

If you come from the world of DOS/Windows, you will be familiar with files that have .bat or .cmd extensions (batch files). They are not similar in content, but are akin in design.

How to execute a shell script

Unlike some silly operating systems, *nix does not rely exclusively on extensions to determine what to do with a file. Permissions are also used. This means that if you attempt to run the shell script after downloading it, it will be the same as trying to "run" any text file. The ".sh" extension is there only for your convenience to recognize that file.

You will need to make the file executable. Let's assume that you have downloaded your file as file.sh, you can then run in your terminal:

chmod +x file.sh

chmod is a command for changing file's permissions, +x sets execute permissions (in this case for everybody) and finally you have your file name.

You can also do it in GUI. Most of the time you can right click on the file and select properties, in XUbuntu the permissions options look like this:

File permissions in XUbuntu

If you do not wish to change the permissions. You can also force the shell to run the command. In the terminal you can run:

bash file.sh

The shell should be the same as in the first line of your script.

How safe is it?

You may find it weird that you must perform another task manually in order to execute a file. But this is partially because of strong need for security.

Basically when you download and run a bash script, it is the same thing as somebody telling you "run all these commands in sequence on your computer, I promise that the results will be good and safe". Ask yourself if you trust the party that has supplied this file, ask yourself if you are sure that have downloaded the file from the same place as you thought, maybe even have a glance inside to see if something looks out of place (although that requires that you know something about *nix commands and bash programming).

Unfortunately apart from the warning above I cannot give a step-by-step description of what you should do to prevent evil things from happening with your computer; so just keep in mind that any time you get and run an executable file from someone you're actually saying, "Sure, you can use my computer to do something".

How To Save Canvas As An Image With canvas.toDataURL()?

I created a small library that does this (along with some other handy conversions). It's called reimg, and it's really simple to use.

ReImg.fromCanvas(yourCanvasElement).toPng()

GridView - Show headers on empty data source

Add this property to your grid-view : ShowHeaderWhenEmpty="True" it might help just check

Vue template or render function not defined yet I am using neither?

I got same error before I forgot to enclose component content in template element.

I have this initially

import Vue from 'vue';
import VueRouter from 'vue-router';
import Home from './com/Home.vue';

Vue.use(VueRouter);

Vue.router = new VueRouter({
    mode: 'history',
    routes: [
        {
            path: '/',
            name: 'home',
            component: Home
        },
    ]
});

Then in Home.vue I have:

<h1>Hello Vue</h1>

Hence the error:

Failed to mount component: template or render function not defined.

found in

---> <Home> at resources/js/com/Home.vue
       <Root>

Enclosing in element fixed the error:

<template>
   <h1>Hello Vue</h1>
</template>

Where do I download JDBC drivers for DB2 that are compatible with JDK 1.5?

you can download and install db2client and looking for - db2jcc.jar - db2jcc_license_cisuz.jar - db2jcc_license_cu.jar - and etc. at C:\Program Files (x86)\IBM\SQLLIB\java

How to view the SQL queries issued by JPA?

In order to view all the SQL and parameters in OpenJPA, put these two parameters in the persistence.xml:

<property name="openjpa.Log" value="DefaultLevel=WARN, Runtime=INFO, Tool=INFO, SQL=TRACE"/>
<property name="openjpa.ConnectionFactoryProperties" value="PrintParameters=true" />

How to round up with excel VBA round()?

Used the function "RDown" and "RUp" from ShamBhagwat and created another function that will return the round part (without the need to give "digits" for input)

Function RoundDown(a As Double, digits As Integer) As Double
    RoundDown = Int((a + (1 / (10 ^ (digits + 1)))) * (10 ^ digits)) / (10 ^ digits)
End Function

Function RoundUp(a As Double, digits As Integer) As Double
    RoundUp = RoundDown(a + (5 / (10 ^ (digits + 1))), digits)
End Function

Function RDownAuto(a As Double) As Double
    Dim i As Integer
    For i = 0 To 17
        If Abs(a * 10) > WorksheetFunction.Power(10, -(i - 1)) Then
            If a > 0 Then
                RDownAuto = RoundDown(a, i)
            Else
                RDownAuto = RoundUp(a, i)
            End If
        Exit Function
        End If
    Next
End Function

the output will be:

RDownAuto(458.067)=458
RDownAuto(10.11)=10
RDownAuto(0.85)=0.8
RDownAuto(0.0052)=0.005
RDownAuto(-458.067)=-458
RDownAuto(-10.11)=-10
RDownAuto(-0.85)=-0.8
RDownAuto(-0.0052)=-0.005

Simplest way to detect keypresses in javascript

Don't over complicate.

  document.addEventListener('keydown', logKey);
    function logKey(e) {
      if (`${e.code}` == "ArrowRight") {
        //code here
      }
          if (`${e.code}` == "ArrowLeft") {
        //code here
      }
          if (`${e.code}` == "ArrowDown") {
        //code here
      }
          if (`${e.code}` == "ArrowUp") {
        //code here
      }
    }

Get the year from specified date php

$date = DateTime::createFromFormat("Y-m-d", "2068-06-15");
echo $date->format("Y");

The DateTime class does not use an unix timestamp internally, so it han handle dates before 1970 or after 2038.

How to select the first row of each group?

Window functions:

Something like this should do the trick:

import org.apache.spark.sql.functions.{row_number, max, broadcast}
import org.apache.spark.sql.expressions.Window

val df = sc.parallelize(Seq(
  (0,"cat26",30.9), (0,"cat13",22.1), (0,"cat95",19.6), (0,"cat105",1.3),
  (1,"cat67",28.5), (1,"cat4",26.8), (1,"cat13",12.6), (1,"cat23",5.3),
  (2,"cat56",39.6), (2,"cat40",29.7), (2,"cat187",27.9), (2,"cat68",9.8),
  (3,"cat8",35.6))).toDF("Hour", "Category", "TotalValue")

val w = Window.partitionBy($"hour").orderBy($"TotalValue".desc)

val dfTop = df.withColumn("rn", row_number.over(w)).where($"rn" === 1).drop("rn")

dfTop.show
// +----+--------+----------+
// |Hour|Category|TotalValue|
// +----+--------+----------+
// |   0|   cat26|      30.9|
// |   1|   cat67|      28.5|
// |   2|   cat56|      39.6|
// |   3|    cat8|      35.6|
// +----+--------+----------+

This method will be inefficient in case of significant data skew.

Plain SQL aggregation followed by join:

Alternatively you can join with aggregated data frame:

val dfMax = df.groupBy($"hour".as("max_hour")).agg(max($"TotalValue").as("max_value"))

val dfTopByJoin = df.join(broadcast(dfMax),
    ($"hour" === $"max_hour") && ($"TotalValue" === $"max_value"))
  .drop("max_hour")
  .drop("max_value")

dfTopByJoin.show

// +----+--------+----------+
// |Hour|Category|TotalValue|
// +----+--------+----------+
// |   0|   cat26|      30.9|
// |   1|   cat67|      28.5|
// |   2|   cat56|      39.6|
// |   3|    cat8|      35.6|
// +----+--------+----------+

It will keep duplicate values (if there is more than one category per hour with the same total value). You can remove these as follows:

dfTopByJoin
  .groupBy($"hour")
  .agg(
    first("category").alias("category"),
    first("TotalValue").alias("TotalValue"))

Using ordering over structs:

Neat, although not very well tested, trick which doesn't require joins or window functions:

val dfTop = df.select($"Hour", struct($"TotalValue", $"Category").alias("vs"))
  .groupBy($"hour")
  .agg(max("vs").alias("vs"))
  .select($"Hour", $"vs.Category", $"vs.TotalValue")

dfTop.show
// +----+--------+----------+
// |Hour|Category|TotalValue|
// +----+--------+----------+
// |   0|   cat26|      30.9|
// |   1|   cat67|      28.5|
// |   2|   cat56|      39.6|
// |   3|    cat8|      35.6|
// +----+--------+----------+

With DataSet API (Spark 1.6+, 2.0+):

Spark 1.6:

case class Record(Hour: Integer, Category: String, TotalValue: Double)

df.as[Record]
  .groupBy($"hour")
  .reduce((x, y) => if (x.TotalValue > y.TotalValue) x else y)
  .show

// +---+--------------+
// | _1|            _2|
// +---+--------------+
// |[0]|[0,cat26,30.9]|
// |[1]|[1,cat67,28.5]|
// |[2]|[2,cat56,39.6]|
// |[3]| [3,cat8,35.6]|
// +---+--------------+

Spark 2.0 or later:

df.as[Record]
  .groupByKey(_.Hour)
  .reduceGroups((x, y) => if (x.TotalValue > y.TotalValue) x else y)

The last two methods can leverage map side combine and don't require full shuffle so most of the time should exhibit a better performance compared to window functions and joins. These cane be also used with Structured Streaming in completed output mode.

Don't use:

df.orderBy(...).groupBy(...).agg(first(...), ...)

It may seem to work (especially in the local mode) but it is unreliable (see SPARK-16207, credits to Tzach Zohar for linking relevant JIRA issue, and SPARK-30335).

The same note applies to

df.orderBy(...).dropDuplicates(...)

which internally uses equivalent execution plan.

How to open a new HTML page using jQuery?

Use window.open("file2.html");

Syntax

var windowObjectReference = window.open(strUrl, strWindowName[, strWindowFeatures]);

Return value and parameters

windowObjectReference 

A reference to the newly created window. If the call failed, it will be null. The reference can be used to access properties and methods of the new window provided it complies with Same origin policy security requirements.

strUrl 

The URL to be loaded in the newly opened window. strUrl can be an HTML document on the web, image file or any resource supported by the browser.

strWindowName 

A string name for the new window. The name can be used as the target of links and forms using the target attribute of an <a> or <form> element. The name should not contain any blank space. Note that strWindowName does not specify the title of the new window.

strWindowFeatures 

Optional parameter listing the features (size, position, scrollbars, etc.) of the new window. The string must not contain any blank space, each feature name and value must be separated by a comma.

Switch statement fall-through...should it be allowed?

It is powerful and dangerous. The biggest problem with fall-through is that it's not explicit. For example, if you come across frequently-edited code that has a switch with fall-throughs, how do you know that's intentional and not a bug?

Anywhere I use it, I ensure that it's properly commented:

switch($var) {
    case 'first':
        // Fall-through
    case 'second':
        i++;
        break;
 }

Show a number to two decimal places

Here's another solution with strtok and str_pad:

$num = 520.00
strtok(round($num, 2), '.') . '.' . str_pad(strtok('.'), 2, '0')

How do you take a git diff file, and apply it to a local branch that is a copy of the same repository?

Copy the diff file to the root of your repository, and then do:

git apply yourcoworkers.diff

More information about the apply command is available on its man page.

By the way: A better way to exchange whole commits by file is the combination of the commands git format-patch on the sender and then git am on the receiver, because it also transfers the authorship info and the commit message.

If the patch application fails and if the commits the diff was generated from are actually in your repo, you can use the -3 option of apply that tries to merge in the changes.

It also works with Unix pipe as follows:

git diff d892531 815a3b5 | git apply

Is there any way to debug chrome in any IOS device

If you don't need full debugging support, you can now view JavaScript console logs directly within Chrome for iOS at chrome://inspect.

https://blog.chromium.org/2019/03/debugging-websites-in-chrome-for-ios.html

Chrome for iOS Console

Eclipse error: indirectly referenced from required .class files?

Point the JRE in the Build path to a JDK. That worked for me.

Getting View's coordinates relative to the root layout

The Android API already provides a method to achieve that. Try this:

Rect offsetViewBounds = new Rect();
//returns the visible bounds
childView.getDrawingRect(offsetViewBounds);
// calculates the relative coordinates to the parent
parentViewGroup.offsetDescendantRectToMyCoords(childView, offsetViewBounds); 

int relativeTop = offsetViewBounds.top;
int relativeLeft = offsetViewBounds.left;

Here is the doc

How can I check if a file exists in Perl?

You might want a variant of exists ... perldoc -f "-f"

      -X FILEHANDLE
       -X EXPR
       -X DIRHANDLE
       -X      A file test, where X is one of the letters listed below.  This unary operator takes one argument,
               either a filename, a filehandle, or a dirhandle, and tests the associated file to see if something is
               true about it.  If the argument is omitted, tests $_, except for "-t", which tests STDIN.  Unless
               otherwise documented, it returns 1 for true and '' for false, or the undefined value if the file
               doesn’t exist.  Despite the funny names, precedence is the same as any other named unary operator.
               The operator may be any of:

                   -r  File is readable by effective uid/gid.
                   -w  File is writable by effective uid/gid.
                   -x  File is executable by effective uid/gid.
                   -o  File is owned by effective uid.

                   -R  File is readable by real uid/gid.
                   -W  File is writable by real uid/gid.
                   -X  File is executable by real uid/gid.
                   -O  File is owned by real uid.

                   -e  File exists.
                   -z  File has zero size (is empty).
                   -s  File has nonzero size (returns size in bytes).

                   -f  File is a plain file.
                   -d  File is a directory.
                   -l  File is a symbolic link.
                   -p  File is a named pipe (FIFO), or Filehandle is a pipe.
                   -S  File is a socket.
                   -b  File is a block special file.
                   -c  File is a character special file.
                   -t  Filehandle is opened to a tty.

                   -u  File has setuid bit set.
                   -g  File has setgid bit set.
                   -k  File has sticky bit set.

                   -T  File is an ASCII text file (heuristic guess).
                   -B  File is a "binary" file (opposite of -T).

                   -M  Script start time minus file modification time, in days.

What's the difference between a 302 and a 307 redirect?

302 is temporary redirect, which is generated by the server whereas 307 is internal redirect response generated by the browser. Internal redirect means that redirect is done automatically by browser internally, basically the browser alters the entered url from http to https in get request by itself before making the request so request for unsecured connection is never made to the internet. Whether browser will alter the url to https or not depends upon the hsts preload list that comes preinstalled with the browser. You can also add any site which support https to the list by entering the domain in the hsts preload list of your own browser which is at chrome://net-internals/#hsts.One more thing website domains can be added by their owners to preload list by filling up the form at https://hstspreload.org/ so that it comes preinstalled in browsers for every user even though I mention you can do particularly for yourself also.


Let me explain with an example:
I made a get request to http://www.pentesteracademy.com which supports only https and I don't have that domain in my hsts preload list on my browser as site owner has not registered for it to come with preinstalled hsts preload list. request and response headers
GET request for unsecure version of the site is redirected to secure version(see http header named location for that in response in above image).
Now I add the site to my own browser preload list by adding its domain in Add hsts domain form at chrome://net-internals/#hsts, which modifies my personal preload list on my chrome browser.Be sure to select include subdomains for STS option there.
Let's see the request and response for the same website now after adding it to hsts preload list.
request and response headers
you can see the internal redirect 307 there in response headers, actually this response is generated by your browser not by server.
Also HSTS preload list can help prevent users reach the unsecure version of site as 302 redirect are prone to mitm attacks.
Hope I somewhat helped you understand more about redirects.

No resource found that matches the given name '@style/ Theme.Holo.Light.DarkActionBar'

If you use android studio, this might be useful for you.

I had a similar problem and i solved it by changing the skd path from the default C:\Program Files (x86)\Android\android-studio\sdk to C:\Program Files (x86)\Android\android-sdk .

It seems the problem came from the compiler version (gradle sets it automatically to the highest one available in the sdk folder) which doesn't support this theme, and since android studio had only the api 7 in its sdk folder, it gave me this error.

For more information on how to change Android sdk path in Android Studio: Android Studio - How to Change Android SDK Path

Haskell: Converting Int to String

The opposite of read is show.

Prelude> show 3
"3"

Prelude> read $ show 3 :: Int
3

Jenkins: Is there any way to cleanup Jenkins workspace?

If you want to just remove one dir (or file) you can use Groovy and Manage Jenkins ? Scripts Console run a script which removes it.

For example, you can look at the files with:

dh = new File('./bitnami/jenkins/jenkins_home/workspace/jobname/folder')
dh.eachFile {
  println(it)
}

And then, when you have the folder you want to delete in dh, you could simply append the next code:

dh.deleteDir()

And it will be deleted.

Note: The path shown in the example is for a Bitnami Jenkins installation, yours could be different.

Help with packages in java - import does not work

It sounds like you are on the right track with your directory structure. When you compile the dependent code, specify the -classpath argument of javac. Use the parent directory of the com directory, where com, in turn, contains company/thing/YourClass.class

So, when you do this:

javac -classpath <parent> client.java

The <parent> should be referring to the parent of com. If you are in com, it would be ../.

How to navigate through a vector using iterators? (C++)

You need to make use of the begin and end method of the vector class, which return the iterator referring to the first and the last element respectively.

using namespace std;  

vector<string> myvector;  // a vector of stings.


// push some strings in the vector.
myvector.push_back("a");
myvector.push_back("b");
myvector.push_back("c");
myvector.push_back("d");


vector<string>::iterator it;  // declare an iterator to a vector of strings
int n = 3;  // nth element to be found.
int i = 0;  // counter.

// now start at from the beginning
// and keep iterating over the element till you find
// nth element...or reach the end of vector.
for(it = myvector.begin(); it != myvector.end(); it++,i++ )    {
    // found nth element..print and break.
    if(i == n) {
        cout<< *it << endl;  // prints d.
        break;
    }
}

// other easier ways of doing the same.
// using operator[]
cout<<myvector[n]<<endl;  // prints d.

// using the at method
cout << myvector.at(n) << endl;  // prints d.

How can I recover a lost commit in Git?

Before answering, let's add some background, explaining what this HEAD is.

First of all what is HEAD?

HEAD is simply a reference to the current commit (latest) on the current branch.
There can only be a single HEAD at any given time (excluding git worktree).

The content of HEAD is stored inside .git/HEAD and it contains the 40 bytes SHA-1 of the current commit.


detached HEAD

If you are not on the latest commit - meaning that HEAD is pointing to a prior commit in history it's called detached HEAD.

Enter image description here

On the command line, it will look like this - SHA-1 instead of the branch name since the HEAD is not pointing to the tip of the current branch:

Enter image description here

Enter image description here


A few options on how to recover from a detached HEAD:


git checkout

git checkout <commit_id>
git checkout -b <new branch> <commit_id>
git checkout HEAD~X // x is the number of commits t go back

This will checkout new branch pointing to the desired commit.
This command will checkout to a given commit.
At this point, you can create a branch and start to work from this point on.

# Checkout a given commit.
# Doing so will result in a `detached HEAD` which mean that the `HEAD`
# is not pointing to the latest so you will need to checkout branch
# in order to be able to update the code.
git checkout <commit-id>

# Create a new branch forked to the given commit
git checkout -b <branch name>

git reflog

You can always use the reflog as well.
git reflog will display any change which updated the HEAD and checking out the desired reflog entry will set the HEAD back to this commit.

Every time the HEAD is modified there will be a new entry in the reflog

git reflog
git checkout HEAD@{...}

This will get you back to your desired commit

Enter image description here


git reset --hard <commit_id>

"Move" your HEAD back to the desired commit.

# This will destroy any local modifications.
# Don't do it if you have uncommitted work you want to keep.
git reset --hard 0d1d7fc32

# Alternatively, if there's work to keep:
git stash
git reset --hard 0d1d7fc32
git stash pop
# This saves the modifications, then reapplies that patch after resetting.
# You could get merge conflicts if you've modified things which were
# changed since the commit you reset to.
  • Note: (Since Git 2.7) you can also use the git rebase --no-autostash as well.

git revert <sha-1>

"Undo" the given commit or commit range.
The reset command will "undo" any changes made in the given commit.
A new commit with the undo patch will be committed while the original commit will remain in the history as well.

# Add a new commit with the undo of the original one.
# The <sha-1> can be any commit(s) or commit range
git revert <sha-1>

This schema illustrates which command does what.
As you can see there, reset && checkout modify the HEAD.

Enter image description here

EXEC sp_executesql with multiple parameters

maybe this help :

declare 
@statement AS NVARCHAR(MAX)
,@text1 varchar(50)='hello'
,@text2 varchar(50)='world'

set @statement = '
select '''+@text1+''' + '' beautifull '' + ''' + @text2 + ''' 
'
exec sp_executesql @statement;

this is same as below :

select @text1 + ' beautifull ' + @text2

Move top 1000 lines from text file to a new file using Unix shell commands

head -1000 input > output && sed -i '1,+999d' input

For example:

$ cat input 
1
2
3
4
5
6
$ head -3 input > output && sed -i '1,+2d' input
$ cat input 
4
5
6
$ cat output 
1
2
3

Sort array by firstname (alphabetically) in Javascript

Nice little ES6 one liner:

users.sort((a, b) => a.firstname !== b.firstname ? a.firstname < b.firstname ? -1 : 1 : 0);

IntelliJ IDEA 13 uses Java 1.5 despite setting to 1.7

Please check your project/module language levels (Project Structure | Project; Project Structure | Modules | module-name | Sources). You might also want to take a look at Settings | Compiler | Java Compiler | Per-module bytecode version.

Set also this:

File -> Project Structure -> Modules :: Sources (next to Paths and Dependencies) and that has a "Language level" option which also needs to be set correctly.

Can I do Android Programming in C++, C?

You can take a look also at C++ Builder XE6, and XE7 supports android in c++ code, and with Firemonkey library.

http://www.embarcadero.com/products/cbuilder

Pretty easy way to start, and native code. But the binaries have a big size.

How to run function in AngularJS controller on document ready?

We can use the angular.element(document).ready() method to attach callbacks for when the document is ready. We can simply attach the callback in the controller like so:

angular.module('MyApp', [])

.controller('MyCtrl', [function() {
    angular.element(document).ready(function () {
        document.getElementById('msg').innerHTML = 'Hello';
    });
}]);

http://jsfiddle.net/jgentes/stwyvq38/1/

Bash script and /bin/bash^M: bad interpreter: No such file or directory

Run following command in terminal

sed -i -e 's/\r$//' scriptname.sh

Then try

./scriptname.sh

It should work.

Understanding the Linux oom-killer's logs

This webpage have an explanation and a solution.

The solution is:

To fix this problem the behavior of the kernel has to be changed, so it will no longer overcommit the memory for application requests. Finally I have included those mentioned values into the /etc/sysctl.conf file, so they get automatically applied on start-up:

vm.overcommit_memory = 2

vm.overcommit_ratio = 80

Dictionary returning a default value if the key does not exist

TryGetValue will already assign the default value for the type to the dictionary, so you can just use:

dictionary.TryGetValue(key, out value);

and just ignore the return value. However, that really will just return default(TValue), not some custom default value (nor, more usefully, the result of executing a delegate). There's nothing more powerful built into the framework. I would suggest two extension methods:

public static TValue GetValueOrDefault<TKey, TValue>
    (this IDictionary<TKey, TValue> dictionary, 
     TKey key,
     TValue defaultValue)
{
    TValue value;
    return dictionary.TryGetValue(key, out value) ? value : defaultValue;
}

public static TValue GetValueOrDefault<TKey, TValue>
    (this IDictionary<TKey, TValue> dictionary,
     TKey key,
     Func<TValue> defaultValueProvider)
{
    TValue value;
    return dictionary.TryGetValue(key, out value) ? value
         : defaultValueProvider();
}

(You may want to put argument checking in, of course :)

Display encoded html with razor

You can also simply use the HtmlString class

    @(new HtmlString(Model.Content))

Laravel: getting a a single value from a MySQL query

On laravel 5.6 it has a very simple solution:

User::where('username', $username)->first()->groupName;

It will return groupName as a string.

Ajax success event not working

I was returning valid JSON, getting a response of 200 in my "complete" callback, and could see it in the chrome network console... BUT I hadn't specified

dataType: "json"

once I did, unlike the "accepted answer", that actually fixed the problem.

excel delete row if column contains value from to-remove-list

Given sheet 2:

ColumnA
-------
apple
orange

You can flag the rows in sheet 1 where a value exists in sheet 2:

ColumnA  ColumnB
-------  --------------
pear     =IF(ISERROR(VLOOKUP(A1,Sheet2!A:A,1,FALSE)),"Keep","Delete")
apple    =IF(ISERROR(VLOOKUP(A2,Sheet2!A:A,1,FALSE)),"Keep","Delete")
cherry   =IF(ISERROR(VLOOKUP(A3,Sheet2!A:A,1,FALSE)),"Keep","Delete")
orange   =IF(ISERROR(VLOOKUP(A4,Sheet2!A:A,1,FALSE)),"Keep","Delete")
plum     =IF(ISERROR(VLOOKUP(A5,Sheet2!A:A,1,FALSE)),"Keep","Delete")

The resulting data looks like this:

ColumnA  ColumnB
-------  --------------
pear     Keep
apple    Delete
cherry   Keep
orange   Delete
plum     Keep

You can then easily filter or sort sheet 1 and delete the rows flagged with 'Delete'.

How to read text files with ANSI encoding and non-English letters?

You get the question-mark-diamond characters when your textfile uses high-ANSI encoding -- meaning it uses characters between 127 and 255. Those characters have the eighth (i.e. the most significant) bit set. When ASP.NET reads the textfile it assumes UTF-8 encoding, and that most significant bit has a special meaning.

You must force ASP.NET to interpret the textfile as high-ANSI encoding, by telling it the codepage is 1252:

String textFilePhysicalPath = System.Web.HttpContext.Current.Server.MapPath("~/textfiles/MyInputFile.txt");
String contents = File.ReadAllText(textFilePhysicalPath, System.Text.Encoding.GetEncoding(1252));
lblContents.Text = contents.Replace("\n", "<br />");  // change linebreaks to HTML

Typescript: difference between String and string

In JavaScript strings can be either string primitive type or string objects. The following code shows the distinction:

var a: string = 'test'; // string literal
var b: String = new String('another test'); // string wrapper object

console.log(typeof a); // string
console.log(typeof b); // object

Your error:

Type 'String' is not assignable to type 'string'. 'string' is a primitive, but 'String' is a wrapper object. Prefer using 'string' when possible.

Is thrown by the TS compiler because you tried to assign the type string to a string object type (created via new keyword). The compiler is telling you that you should use the type string only for strings primitive types and you can't use this type to describe string object types.

Declaring a xsl variable and assigning value to it

No, unlike in a lot of other languages, XSLT variables cannot change their values after they are created. You can however, avoid extraneous code with a technique like this:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:output method="xml" indent="yes" omit-xml-declaration="yes"/>

  <xsl:variable name="mapping">
    <item key="1" v1="A" v2="B" />
    <item key="2" v1="X" v2="Y" />
  </xsl:variable>
  <xsl:variable name="mappingNode"
                select="document('')//xsl:variable[@name = 'mapping']" />

  <xsl:template match="....">
    <xsl:variable name="testVariable" select="'1'" />

    <xsl:variable name="values" select="$mappingNode/item[@key = $testVariable]" />

    <xsl:variable name="variable1" select="$values/@v1" />
    <xsl:variable name="variable2" select="$values/@v2" />
  </xsl:template>
</xsl:stylesheet>

In fact, once you've got the values variable, you may not even need separate variable1 and variable2 variables. You could just use $values/@v1 and $values/@v2 instead.

android.content.Context.getPackageName()' on a null object reference

For me the problem was that I was passing Activity to the constructor, not Context

public Adapter(Activity activity, List<MediaItem> items, boolean can) {
    mItems = items;
    canEdit = can;
    mActivity = activity;
}

and using this activity to getDefaultSharedPreferences(), so I changed the Activity to Context and I was still calling the Adapter constructor with MainActivity.this

VBA Go to last empty row

This does it:

Do
   c = c + 1
Loop While Cells(c, "A").Value <> ""

'prints the last empty row
Debug.Print c

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

Using <section> may be neater, help screen readers and SEO while <div> is smaller in bytes and quicker to type

Overall very little difference.

Also, would not recommend putting <section> in a <section>, instead place a <div> inside a <section>

Sorting arraylist in alphabetical order (case insensitive)

KOTLIN DEVELOPERS

For Custome List, if you want to sort based on one String then you can use this:

phoneContactArrayList.sortWith(Comparator { item, t1 ->
        val s1: String = item.phoneContactUserName
        val s2: String = t1.phoneContactUserName
        s1.compareTo(s2, ignoreCase = true)
    })

How to increase font size in NeatBeans IDE?

You can create your own shortcut for increase/Decrease Netbeans Fonts size

just goto Tools > Options > Keymaps than search zoom

click on three (...) dot and click Edit

press your_shortcut_keys ( what ever shortcut you want to set)

How to store values from foreach loop into an array?

this question seem quite old but incase you come pass it, you can use the PHP inbuilt function array_push() to push data in an array using the example below.

<?php
    $item = array();
    foreach($group_membership as $i => $username) {
        array_push($item, $username);
    }
    print_r($items);
?>

What is the PHP syntax to check "is not null" or an empty string?

Use empty(). It checks for both empty strings and null.

if (!empty($_POST['user'])) {
  // do stuff
}

From the manual:

The following things are considered to be empty:

"" (an empty string)  
0 (0 as an integer)  
0.0 (0 as a float)  
"0" (0 as a string)    
NULL  
FALSE  
array() (an empty array)  
var $var; (a variable declared, but without a value in a class)  

SQL: capitalize first letter only

select replace(wm_concat(new),',','-') exp_res from (select distinct initcap(substr(name,decode(level,1,1,instr(name,'-',1,level-1)+1),decode(level,(length(name)-length(replace(name,'-','')))+1,9999,instr(name,'-',1,level)-1-decode(level,1,0,instr(name,'-',1,level-1))))) new from table;
connect by level<= (select (length(name)-length(replace(name,'-','')))+1 from table));

JPA or JDBC, how are they different?

JDBC is a much lower-level (and older) specification than JPA. In it's bare essentials, JDBC is an API for interacting with a database using pure SQL - sending queries and retrieving results. It has no notion of objects or hierarchies. When using JDBC, it's up to you to translate a result set (essentially a row/column matrix of values from one or more database tables, returned by your SQL query) into Java objects.

Now, to understand and use JDBC it's essential that you have some understanding and working knowledge of SQL. With that also comes a required insight into what a relational database is, how you work with it and concepts such as tables, columns, keys and relationships. Unless you have at least a basic understanding of databases, SQL and data modelling you will not be able to make much use of JDBC since it's really only a thin abstraction on top of these things.

How to set opacity to the background color of a div?

I would say that the easiest way is to use transparent background image.

http://jsfiddle.net/m48nH/

background: url("http://musescore.org/sites/musescore.org/files/blue-translucent.png") repeat top left;

How to enable CORS in ASP.NET Core

Got this working with .Net Core 3.1 as follows

1.Make sure you place the UseCors code between app.UseRouting(); and app.UseAuthentication();

        app.UseHttpsRedirection();

        app.UseRouting();
        app.UseCors("CorsApi");

        app.UseAuthentication();
        app.UseAuthorization();

        app.UseEndpoints(endpoints => {
            endpoints.MapControllers();
        });

2.Then place this code in the ConfigureServices method

services.AddCors(options =>
        {
            options.AddPolicy("CorsApi",
                builder => builder.WithOrigins("http://localhost:4200", "http://mywebsite.com")
            .AllowAnyHeader()
            .AllowAnyMethod());
        });

3.And above the base controller I placed this

[EnableCors("CorsApi")]
[Route("api/[controller]")]
[ApiController]
public class BaseController : ControllerBase

Now all my controllers will inherit from the BaseController and will have CORS enabled

Add all files to a commit except a single file?

To keep the change in file but not to commit I did this

git add .

git reset -- main/dontcheckmein.txt

git commit -m "commit message"

to verify the file is excluded do

git status

NGINX: upstream timed out (110: Connection timed out) while reading response header from upstream

Hopefully it helps someone: I ran into this error and the cause was wrong permission on the log folder for phpfpm, after changing it so phpfpm could write to it, everything was fine.

Explanation on Integer.MAX_VALUE and Integer.MIN_VALUE to find min and max value in an array

but as for this method, I don't understand the purpose of Integer.MAX_VALUE and Integer.MIN_VALUE.

By starting out with smallest set to Integer.MAX_VALUE and largest set to Integer.MIN_VALUE, they don't have to worry later about the special case where smallest and largest don't have a value yet. If the data I'm looking through has a 10 as the first value, then numbers[i]<smallest will be true (because 10 is < Integer.MAX_VALUE) and we'll update smallest to be 10. Similarly, numbers[i]>largest will be true because 10 is > Integer.MIN_VALUE and we'll update largest. And so on.

Of course, when doing this, you must ensure that you have at least one value in the data you're looking at. Otherwise, you end up with apocryphal numbers in smallest and largest.


Note the point Onome Sotu makes in the comments:

...if the first item in the array is larger than the rest, then the largest item will always be Integer.MIN_VALUE because of the else-if statement.

Which is true; here's a simpler example demonstrating the problem (live copy):

public class Example
{
    public static void main(String[] args) throws Exception {
        int[] values = {5, 1, 2};
        int smallest = Integer.MAX_VALUE;
        int largest  = Integer.MIN_VALUE;
        for (int value : values) {
            if (value < smallest) {
                smallest = value;
            } else if (value > largest) {
                largest = value;
            }
        }
        System.out.println(smallest + ", " + largest); // 1, 2 -- WRONG
    }
}

To fix it, either:

  1. Don't use else, or

  2. Start with smallest and largest equal to the first element, and then loop the remaining elements, keeping the else if.

Here's an example of that second one (live copy):

public class Example
{
    public static void main(String[] args) throws Exception {
        int[] values = {5, 1, 2};
        int smallest = values[0];
        int largest  = values[0];
        for (int n = 1; n < values.length; ++n) {
            int value = values[n];
            if (value < smallest) {
                smallest = value;
            } else if (value > largest) {
                largest = value;
            }
        }
        System.out.println(smallest + ", " + largest); // 1, 5
    }
}

Android: Color To Int conversion

Paint DOES have set color function.

/**
 * Set the paint's color. Note that the color is an int containing alpha
 * as well as r,g,b. This 32bit value is not premultiplied, meaning that
 * its alpha can be any value, regardless of the values of r,g,b.
 * See the Color class for more details.
 *
 * @param color The new color (including alpha) to set in the paint.
 */
public native void setColor(@ColorInt int color);

As an Android developer, I set paint color like this...

paint.setColor(getResources().getColor(R.color.xxx));

I define the color value on color.xml something like...

<color name="xxx">#008fd2</color>

By the way if you want to the hex RGB value of specific color value, then you can check website like this: http://www.rapidtables.com/web/color/RGB_Color.htm

I hope this helps ! Enjoy coding!

Enabling SSL with XAMPP

For XAMPP, do the following steps:

  1. G:\xampp\apache\conf\extra\httpd-ssl.conf"

  2. Search 'DocumentRoot' text.

  3. Change DocumentRoot DocumentRoot "G:/xampp/htdocs" to DocumentRoot "G:/xampp/htdocs/project name".

Responsive iframe using Bootstrap

Please, Check this out, I hope it's help

<div class="row">
 <iframe class="col-lg-12 col-md-12 col-sm-12" src="http://www.w3schools.com">
 </iframe>
</div>

Simple search MySQL database using php

Just with the above answer I hope it was the problem.

$_POST['search'] instead of $_post['search']

And again use LIKE '%$name%' instead of LIKE '%{$name}%'

Best way to test for a variable's existence in PHP; isset() is clearly broken

Attempting to give an overview of the various discussions and answers:

There is no single answer to the question which can replace all the ways isset can be used. Some use cases are addressed by other functions, while others do not stand up to scrutiny, or have dubious value beyond code golf. Far from being "broken" or "inconsistent", other use cases demonstrate why isset's reaction to null is the logical behaviour.

Real use cases (with solutions)

1. Array keys

Arrays can be treated like collections of variables, with unset and isset treating them as though they were. However, since they can be iterated, counted, etc, a missing value is not the same as one whose value is null.

The answer in this case, is to use array_key_exists() instead of isset().

Since this is takes the array to check as a function argument, PHP will still raise "notices" if the array itself doesn't exist. In some cases, it can validly be argued that each dimension should have been initialised first, so the notice is doing its job. For other cases, a "recursive" array_key_exists function, which checked each dimension of the array in turn, would avoid this, but would basically be the same as @array_key_exists. It is also somewhat tangential to the handling of null values.

2. Object properties

In the traditional theory of "Object-Oriented Programming", encapsulation and polymorphism are key properties of objects; in a class-based OOP implementation like PHP's, the encapsulated properties are declared as part of the class definition, and given access levels (public, protected, or private).

However, PHP also allows you to dynamically add properties to an object, like you would keys to an array, and some people use class-less objects (technically, instances of the built in stdClass, which has no methods or private functionality) in a similar way to associative arrays. This leads to situations where a function may want to know if a particular property has been added to the object given to it.

As with array keys, a solution for checking object properties is included in the language, called, reasonably enough, property_exists.

Non-justifiable use cases, with discussion

3. register_globals, and other pollution of the global namespace

The register_globals feature added variables to the global scope whose names were determined by aspects of the HTTP request (GET and POST parameters, and cookies). This can lead to buggy and insecure code, which is why it has been disabled by default since PHP 4.2, released Aug 2000 and removed completely in PHP 5.4, released Mar 2012. However, it's possible that some systems are still running with this feature enabled or emulated. It's also possible to "pollute" the global namespace in other ways, using the global keyword, or $GLOBALS array.

Firstly, register_globals itself is unlikely to unexpectedly produce a null variable, since the GET, POST, and cookie values will always be strings (with '' still returning true from isset), and variables in the session should be entirely under the programmer's control.

Secondly, pollution of a variable with the value null is only an issue if this over-writes some previous initialization. "Over-writing" an uninitialized variable with null would only be problematic if code somewhere else was distinguishing between the two states, so on its own this possibility is an argument against making such a distinction.

4. get_defined_vars and compact

A few rarely-used functions in PHP, such as get_defined_vars and compact, allow you to treat variable names as though they were keys in an array. For global variables, the super-global array $GLOBALS allows similar access, and is more common. These methods of access will behave differently if a variable is not defined in the relevant scope.

Once you've decided to treat a set of variables as an array using one of these mechanisms, you can do all the same operations on it as on any normal array. Consequently, see 1.

Functionality that existed only to predict how these functions are about to behave (e.g. "will there be a key 'foo' in the array returned by get_defined_vars?") is superfluous, since you can simply run the function and find out with no ill effects.

4a. Variable variables ($$foo)

While not quite the same as functions which turn a set of variables into an associative array, most cases using "variable variables" ("assign to a variable named based on this other variable") can and should be changed to use an associative array instead.

A variable name, fundamentally, is the label given to a value by the programmer; if you're determining it at run-time, it's not really a label but a key in some key-value store. More practically, by not using an array, you are losing the ability to count, iterate, etc; it can also become impossible to have a variable "outside" the key-value store, since it might be over-written by $$foo.

Once changed to use an associative array, the code will be amenable to solution 1. Indirect object property access (e.g. $foo->$property_name) can be addressed with solution 2.

5. isset is so much easier to type than array_key_exists

I'm not sure this is really relevant, but yes, PHP's function names can be pretty long-winded and inconsistent sometimes. Apparently, pre-historic versions of PHP used a function name's length as a hash key, so Rasmus deliberately made up function names like htmlspecialchars so they would have an unusual number of characters...

Still, at least we're not writing Java, eh? ;)

6. Uninitialized variables have a type

The manual page on variable basics includes this statement:

Uninitialized variables have a default value of their type depending on the context in which they are used

I'm not sure whether there is some notion in the Zend Engine of "uninitialized but known type" or whether this is reading too much into the statement.

What is clear is that it makes no practical difference to their behaviour, since the behaviours described on that page for uninitialized variables are identical to the behaviour of a variable whose value is null. To pick one example, both $a and $b in this code will end up as the integer 42:

unset($a);
$a += 42;

$b = null;
$b += 42;

(The first will raise a notice about an undeclared variable, in an attempt to make you write better code, but it won't make any difference to how the code actually runs.)

99. Detecting if a function has run

(Keeping this one last, as it's much longer than the others. Maybe I'll edit it down later...)

Consider the following code:

$test_value = 'hello';
foreach ( $list_of_things as $thing ) {
    if ( some_test($thing, $test_value) ) {
        $result = some_function($thing);
    }
}
if ( isset($result) ) {
    echo 'The test passed at least once!';
}

If some_function can return null, there's a possibility that the echo won't be reached even though some_test returned true. The programmer's intention was to detect when $result had never been set, but PHP does not allow them to do so.

However, there are other problems with this approach, which become clear if you add an outer loop:

foreach ( $list_of_tests as $test_value ) {
    // something's missing here...
    foreach ( $list_of_things as $thing ) {
        if ( some_test($thing, $test_value) ) {
            $result = some_function($thing);
        }
    }
    if ( isset($result) ) {
        echo 'The test passed at least once!';
    }
}

Because $result is never initialized explicitly, it will take on a value when the very first test passes, making it impossible to tell whether subsequent tests passed or not. This is actually an extremely common bug when variables aren't initialised properly.

To fix this, we need to do something on the line where I've commented that something's missing. The most obvious solution is to set $result to a "terminal value" that some_function can never return; if this is null, then the rest of the code will work fine. If there is no natural candidate for a terminal value because some_function has an extremely unpredictable return type (which is probably a bad sign in itself), then an additional boolean value, e.g. $found, could be used instead.

Thought experiment one: the very_null constant

PHP could theoretically provide a special constant - as well as null - for use as a terminal value here; presumably, it would be illegal to return this from a function, or it would be coerced to null, and the same would probably apply to passing it in as a function argument. That would make this very specific case slightly simpler, but as soon as you decided to re-factor the code - for instance, to put the inner loop into a separate function - it would become useless. If the constant could be passed between functions, you could not guarantee that some_function would not return it, so it would no longer be useful as a universal terminal value.

The argument for detecting uninitialised variables in this case boils down to the argument for that special constant: if you replace the comment with unset($result), and treat that differently from $result = null, you are introducing a "value" for $result that cannot be passed around, and can only be detected by specific built-in functions.

Thought experiment two: assignment counter

Another way of thinking about what the last if is asking is "has anything made an assignment to $result?" Rather than considering it to be a special value of $result, you could maybe think of this as "metadata" about the variable, a bit like Perl's "variable tainting". So rather than isset you might call it has_been_assigned_to, and rather than unset, reset_assignment_state.

But if so, why stop at a boolean? What if you want to know how many times the test passed; you could simply extend your metadata to an integer and have get_assignment_count and reset_assignment_count...

Obviously, adding such a feature would have a trade-off in complexity and performance of the language, so it would need to be carefully weighed against its expected usefulness. As with a very_null constant, it would be useful only in very narrow circumstances, and would be similarly resistant to re-factoring.

The hopefully-obvious question is why the PHP runtime engine should assume in advance that you want to keep track of such things, rather than leaving you to do it explicitly, using normal code.

Why is document.write considered a "bad practice"?

It can block your page

document.write only works while the page is loading; If you call it after the page is done loading, it will overwrite the whole page.

This effectively means you have to call it from an inline script block - And that will prevent the browser from processing parts of the page that follow. Scripts and Images will not be downloaded until the writing block is finished.

How do I get the domain originating the request in express.js?

Recently faced a problem with fetching 'Origin' request header, then I found this question. But pretty confused with the results, req.get('host') is deprecated, that's why giving Undefined. Use,

    req.header('Origin');
    req.header('Host');
    // this method can be used to access other request headers like, 'Referer', 'User-Agent' etc.

How to call getResources() from a class which has no context?

It can easily be done if u had declared a class that extends from Application

This class will be like a singleton, so when u need a context u can get it just like this:

I think this is the better answer and the cleaner

Here is my code from Utilities package:

 public static String getAppNAme(){
     return MyOwnApplication.getInstance().getString(R.string.app_name);
 }

Java Regex to Validate Full Name allow only Spaces and Letters

This works for me with validation of bootstrap

$(document).ready(function() {
$("#fname").keypress(function(e) {
var regex = new RegExp("^[a-zA-Z ]+$");
var str = String.fromCharCode(!e.charCode ? e.which : e.charCode);
if (regex.test(str)) {
 return true;
}

.setAttribute("disabled", false); changes editable attribute to false

Using method set and remove attribute

_x000D_
_x000D_
function radioButton(o) {_x000D_
_x000D_
  var text = document.querySelector("textarea");_x000D_
_x000D_
  if (o.value == "on") {_x000D_
    text.removeAttribute("disabled", "");_x000D_
    text.setAttribute("enabled", "");_x000D_
  } else {_x000D_
    text.removeAttribute("enabled", "");_x000D_
    text.setAttribute("disabled", "");_x000D_
  }_x000D_
  _x000D_
}
_x000D_
<input type="radio" name="radioButton" value="on" onclick = "radioButton(this)" />Enable_x000D_
<input type="radio" name="radioButton" value="off" onclick = "radioButton(this)" />Disabled<hr/>_x000D_
_x000D_
<textarea disabled ></textarea>
_x000D_
_x000D_
_x000D_

Replacing a character from a certain index

You can't replace a letter in a string. Convert the string to a list, replace the letter, and convert it back to a string.

>>> s = list("Hello world")
>>> s
['H', 'e', 'l', 'l', 'o', ' ', 'W', 'o', 'r', 'l', 'd']
>>> s[int(len(s) / 2)] = '-'
>>> s
['H', 'e', 'l', 'l', 'o', '-', 'W', 'o', 'r', 'l', 'd']
>>> "".join(s)
'Hello-World'

How to concatenate items in a list to a single string?

This will help for sure -

arr=['a','b','h','i']     # let this be the list
s=""                      # creating a empty string
for i in arr:
   s+=i                   # to form string without using any function
print(s) 


       

Customize Bootstrap checkboxes

You have to use Bootstrap version 4 with the custom-* classes to get this style:

_x000D_
_x000D_
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/css/bootstrap.min.css" integrity="sha384-/Y6pD6FV/Vv2HJnA6t+vslU6fwYXjCFtcEpHbNJ0lyAFsXTsjBbfaDjzALeQsN6M" crossorigin="anonymous">_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
_x000D_
<!-- example code of the bootstrap website -->_x000D_
<label class="custom-control custom-checkbox">_x000D_
  <input type="checkbox" class="custom-control-input">_x000D_
  <span class="custom-control-indicator"></span>_x000D_
  <span class="custom-control-description">Check this custom checkbox</span>_x000D_
</label>_x000D_
_x000D_
<!-- your code with the custom classes of version 4 -->_x000D_
<div class="checkbox">_x000D_
  <label class="custom-control custom-checkbox">_x000D_
    <input type="checkbox" [(ngModel)]="rememberMe" name="rememberme" class="custom-control-input">_x000D_
    <span class="custom-control-indicator"></span>_x000D_
    <span class="custom-control-description">Remember me</span>_x000D_
  </label>_x000D_
</div>
_x000D_
_x000D_
_x000D_

Documentation: https://getbootstrap.com/docs/4.0/components/forms/#checkboxes-and-radios-1


Custom checkbox style on Bootstrap version 3?
Bootstrap version 3 doesn't have custom checkbox styles, but you can use your own. In this case: How to style a checkbox using CSS?

These custom styles are only available since version 4.

'dispatch' is not a function when argument to mapToDispatchToProps() in Redux

I solved it by interchanging the arguments, I was using

export default connect(mapDispatchToProps, mapStateToProps)(Checkbox)

which is wrong. The mapStateToProps has to be the first argument:

export default connect(mapStateToProps, mapDispatchToProps)(Checkbox)

It sounds obvious now, but might help someone.

Find out a Git branch creator

Assuming:

  1. branch was made from master
  2. hasn't been merged to master yet

 git log --format="%ae %an" master..<HERE_COMES_THE_BRANCH_NAME> | tail -1

Execution failed for task ':app:compileDebugJavaWithJavac' Android Studio 3.1 Update

This problem is commonly related to compiler errors in the Java code. Sometimes Android Studio does not show these errors in the Project explorer. However, when a problematic .java file is opened, errors are shown. Try to resolve errors and rebuild the project.

Batch file to restart a service. Windows

net stop <your service> && net start <your service>

No net restart, unfortunately.

How to change background color in android app

you can try with this way

android:background="@color/white"

How to write a file or data to an S3 object using boto3

You may use the below code to write, for example an image to S3 in 2019. To be able to connect to S3 you will have to install AWS CLI using command pip install awscli, then enter few credentials using command aws configure:

import urllib3
import uuid
from pathlib import Path
from io import BytesIO
from errors import custom_exceptions as cex

BUCKET_NAME = "xxx.yyy.zzz"
POSTERS_BASE_PATH = "assets/wallcontent"
CLOUDFRONT_BASE_URL = "https://xxx.cloudfront.net/"


class S3(object):
    def __init__(self):
        self.client = boto3.client('s3')
        self.bucket_name = BUCKET_NAME
        self.posters_base_path = POSTERS_BASE_PATH

    def __download_image(self, url):
        manager = urllib3.PoolManager()
        try:
            res = manager.request('GET', url)
        except Exception:
            print("Could not download the image from URL: ", url)
            raise cex.ImageDownloadFailed
        return BytesIO(res.data)  # any file-like object that implements read()

    def upload_image(self, url):
        try:
            image_file = self.__download_image(url)
        except cex.ImageDownloadFailed:
            raise cex.ImageUploadFailed

        extension = Path(url).suffix
        id = uuid.uuid1().hex + extension
        final_path = self.posters_base_path + "/" + id
        try:
            self.client.upload_fileobj(image_file,
                                       self.bucket_name,
                                       final_path
                                       )
        except Exception:
            print("Image Upload Error for URL: ", url)
            raise cex.ImageUploadFailed

        return CLOUDFRONT_BASE_URL + id

Get column index from column name in python pandas

To modify DSM's answer a bit, get_loc has some weird properties depending on the type of index in the current version of Pandas (1.1.5) so depending on your Index type you might get back an index, a mask, or a slice. This is somewhat frustrating for me because I don't want to modify the entire columns just to extract one variable's index. Much simpler is to avoid the function altogether:

list(df.columns).index('pear')

Very straightforward and probably fairly quick.

Vertical line using XML drawable

add this in your styles.xml

        <style name="Divider">
            <item name="android:layout_width">1dip</item>
            <item name="android:layout_height">match_parent</item>
            <item name="android:background">@color/divider_color</item>
        </style>

        <style name="Divider_invisible">
            <item name="android:layout_width">1dip</item>
            <item name="android:layout_height">match_parent</item>
        </style>

then wrap this style in a linear layout where you want the vertical line, I used the vertical line as a column divider in my table. 

     <TableLayout
                android:id="@+id/table"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                android:stretchColumns="*" >

                <TableRow
                    android:id="@+id/tableRow1"
                    android:layout_width="fill_parent"
                    android:layout_height="match_parent"
                    android:background="#92C94A" >

                    <TextView
                        android:id="@+id/textView11"
                        android:paddingBottom="10dp"
                        android:paddingLeft="5dp"
                        android:paddingRight="5dp"
                        android:paddingTop="10dp" />
    //...................................................................    

                    <LinearLayout
                        android:layout_width="1dp"
                        android:layout_height="match_parent" >

                        <View style="@style/Divider_invisible" />
                    </LinearLayout>
        //...................................................................
                    <TextView
                        android:id="@+id/textView12"
                        android:paddingBottom="10dp"
                        android:paddingLeft="5dp"
                        android:paddingRight="5dp"
                        android:paddingTop="10dp"
                        android:text="@string/main_wo_colon"
                        android:textColor="@color/white"
                        android:textSize="16sp" />
  //...............................................................  
                    <LinearLayout
                        android:layout_width="1dp"
                        android:layout_height="match_parent" >

                        <View style="@style/Divider" />
                    </LinearLayout>

    //...................................................................
                    <TextView
                        android:id="@+id/textView13"
                        android:paddingBottom="10dp"
                        android:paddingLeft="5dp"
                        android:paddingRight="5dp"
                        android:paddingTop="10dp"
                        android:text="@string/side_wo_colon"
                        android:textColor="@color/white"
                        android:textSize="16sp" />

                    <LinearLayout
                        android:layout_width="1dp"
                        android:layout_height="match_parent" >

                        <View style="@style/Divider" />
                    </LinearLayout>

                    <TextView
                        android:id="@+id/textView14"
                        android:paddingBottom="10dp"
                        android:paddingLeft="5dp"
                        android:paddingRight="5dp"
                        android:paddingTop="10dp"
                        android:text="@string/total"
                        android:textColor="@color/white"
                        android:textSize="16sp" />
                </TableRow>

                <!-- display this button in 3rd column via layout_column(zero based) -->

                <TableRow
                    android:id="@+id/tableRow2"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:background="#6F9C33" >

                    <TextView
                        android:id="@+id/textView21"
                        android:padding="5dp"
                        android:text="@string/servings"
                        android:textColor="@color/white"
                        android:textSize="16sp" />

                    <LinearLayout
                        android:layout_width="1dp"
                        android:layout_height="match_parent" >

                        <View style="@style/Divider" />
                    </LinearLayout>

    ..........
    .......
    ......

How to compute the sum and average of elements in an array?

One sneaky way you could do it although it does require the use of (the much hated) eval().

var sum = eval(elmt.join('+')), avg = sum / elmt.length;
document.write("The sum of all the elements is: " + sum + " The average of all the elements is: " + avg + "<br/>");

Just thought I'd post this as one of those 'outside the box' options. You never know, the slyness might grant you (or taketh away) a point.

A regular expression to exclude a word/string

This should do it:

^/\b([a-z0-9]+)\b(?<!ignoreme|ignoreme2|ignoreme3)

You can add as much ignored words as you like, here is a simple PHP implementation:

$ignoredWords = array('ignoreme', 'ignoreme2', 'ignoreme...');

preg_match('~^/\b([a-z0-9]+)\b(?<!' . implode('|', array_map('preg_quote', $ignoredWords)) . ')~i', $string);

error LNK2005: xxx already defined in MSVCRT.lib(MSVCR100.dll) C:\something\LIBCMT.lib(setlocal.obj)

If you VS solution contains several projects, select all of them in the right pane, and press "properties". Then go to C++ -> Code Generation and chose one Run Time library option for all of them

PHP Unset Array value effect on other indexes

Test it yourself, but here's the output.

php -r '$a=array("a","b","c"); print_r($a); unset($a[1]); print_r($a);'
Array
(
    [0] => a
    [1] => b
    [2] => c
)
Array
(
    [0] => a
    [2] => c
)

Switch on Enum in Java

You might be using the enums incorrectly in the switch cases. In comparison with the above example by CoolBeans.. you might be doing the following:

switch(day) {
    case Day.MONDAY:
        // Something..
        break;
    case Day.FRIDAY:
        // Something friday
        break;
}

Make sure that you use the actual enum values instead of EnumType.EnumValue

Eclipse points out this mistake though..

SVN change username

I believe you could create you own branch (using your own credential) from the same trunk as your workmate's branch, merge from your workmate's branch to your working copy and then merge from your branch. All future commit should be marked as coming from you.

Command to change the default home directory of a user

You can do it with:

/etc/passwd

Edit the user home directory and then move the required files and directories to it:

cp/mv -r /home/$user/.bash* /home/newdir

.bash_profile
.ssh/ 

Set the correct permission

chmod -R $user:$user /home/newdir/.bash*

How to update/refresh specific item in RecyclerView

Update single item

  1. Update the data item
  2. Notify the adapter of the change with notifyItemChanged(updateIndex)

Example

Change the "Sheep" item so that it says "I like sheep."

Update single item

String newValue = "I like sheep.";
int updateIndex = 3;
data.set(updateIndex, newValue);
adapter.notifyItemChanged(updateIndex);

My full answer with more examples is here.

MySQL DROP all tables, ignoring foreign keys

I found the generated set of drop statements useful, and recommend these tweaks:

  1. Limit the generated drops to your database like this:
SELECT concat('DROP TABLE IF EXISTS `', table_name, '`;')
FROM information_schema.tables
WHERE table_schema = 'MyDatabaseName';

Note 1: This does not execute the DROP statements, it just gives you a list of them. You will need to cut and paste the output into your SQL engine to execute them.

Note 2: If you have VIEWs, you'll have to correct each DROP TABLE `VIEW_NAME` statement to DROP VIEW `VIEW_NAME` manually.

  1. Note, per http://dev.mysql.com/doc/refman/5.5/en/drop-table.html, dropping with cascade is pointless / misleading:

"RESTRICT and CASCADE are permitted to make porting easier. In MySQL 5.5, they do nothing."

Therefore, in order for the drop statements to work if you need:

SET FOREIGN_KEY_CHECKS = 0

This will disable referential integrity checks - so when you are done performing the drops you need, you will want to reset key checking with

SET FOREIGN_KEY_CHECKS = 1
  1. The final execution should look like:
SET FOREIGN_KEY_CHECKS = 0;
-- Your semicolon separated list of DROP statements here
SET FOREIGN_KEY_CHECKS = 1;

NB: to use output of SELECT easier, mysql -B option can help.

assign function return value to some variable using javascript

The only way to retrieve the correct value in your context is to run $.ajax() function synchronously (what actually contradicts to main AJAX idea). There is the special configuration attribute async you should set to false. In that case the main scope which actually contains $.ajax() function call is paused until the synchronous function is done, so, the return is called only after $.ajax().

function doSomething() {
    var status = 0;
    $.ajax({
        url: 'action.php',
        type: 'POST',
        data: dataString,
        async: false,
        success: function (txtBack) {
            if (txtBack == 1)
                status = 1;
        }
    });

    return status;
}

var response = doSomething();

What does "if (rs.next())" mean?

The next() moves the cursor froward one row from its current position in the resultset. so its evident that if(rs.next()) means that if the next row is not null (means if it exist), Go Ahead.

Now w.r.t your problem,

ResultSet rs = stmt.executeQuery(sql);  //This is wrong
                                  ^       

note that executeQuery(String) is used in case you use a sql-query as string.

Whereas when you use a PreparedStatement, use executeQuery() which executes the SQL query in this PreparedStatement object and returns the ResultSet object generated by the query.

Solution :

Use : ResultSet rs = stmt.executeQuery();

Convert character to ASCII numeric value in java

Convert the char to int.

    String name = "admin";
    int ascii = name.toCharArray()[0];

Also :

int ascii = name.charAt(0);

"Connect failed: Access denied for user 'root'@'localhost' (using password: YES)" from php function

Most likely it is not identifying your user properly. root@localhost. Select the Mysql version your MAMP is using.

/Applications/MAMP/Library/bin/mysqldump -uroot -p db_name > test_db_dump.sql

I actually wrote an alias on my computer so I don't have to remember how to get to the bin directory.

alias mysqldumpMAMP='/Applications/MAMP/Library/bin/mysqldump'

Which allows me to run this:

mysqldumpMAMP -uroot -p db_name > test_db_dump.sql

You can save an alias in your bash profile ~/.bash_profile or ~/.bash_rc

TypeError: 'undefined' is not a function (evaluating '$(document)')

wrap all the script between this...

<script>
    $.noConflict();
    jQuery( document ).ready(function( $ ) {
      // Code that uses jQuery's $ can follow here.
    });
</script>

Many JavaScript libraries use $ as a function or variable name, just as jQuery does. In jQuery's case, $ is just an alias for jQuery, so all functionality is available without using $. If you need to use another JavaScript library alongside jQuery, return control of $ back to the other library with a call to $.noConflict(). Old references of $ are saved during jQuery initialization; noConflict() simply restores them.

What does ON [PRIMARY] mean?

When you create a database in Microsoft SQL Server you can have multiple file groups, where storage is created in multiple places, directories or disks. Each file group can be named. The PRIMARY file group is the default one, which is always created, and so the SQL you've given creates your table ON the PRIMARY file group.

See MSDN for the full syntax.

Finding the number of non-blank columns in an Excel sheet using VBA

Your example code gets the row number of the last non-blank cell in the current column, and can be rewritten as follows:

Dim lastRow As Long
lastRow = Sheet1.Cells(Rows.Count, 1).End(xlUp).Row
MsgBox lastRow

It is then easy to see that the equivalent code to get the column number of the last non-blank cell in the current row is:

Dim lastColumn As Long
lastColumn = Sheet1.Cells(1, Columns.Count).End(xlToLeft).Column
MsgBox lastColumn

This may also be of use to you:

With Sheet1.UsedRange
    MsgBox .Rows.Count & " rows and " & .Columns.Count & " columns"
End With

but be aware that if column A and/or row 1 are blank, then this will not yield the same result as the other examples above. For more, read up on the UsedRange property.

What is an NP-complete in computer science?

NP-Complete is a class of problems.

The class P consists of those problems that are solvable in polynomial time. For example, they could be solved in O(nk) for some constant k, where n is the size of the input. Simply put, you can write a program that will run in reasonable time.

The class NP consists of those problems that are verifiable in polynomial time. That is, if we are given a potential solution, then we could check if the given solution is correct in polynomial time.

Some examples are the Boolean Satisfiability (or SAT) problem, or the Hamiltonian-cycle problem. There are many problems that are known to be in the class NP.

NP-Complete means the problem is at least as hard as any problem in NP.

It is important to computer science because it has been proven that any problem in NP can be transformed into another problem in NP-complete. That means that a solution to any one NP-complete problem is a solution to all NP problems.

Many algorithms in security depends on the fact that no known solutions exist for NP hard problems. It would definitely have a significant impact on computing if a solution were found.

Passing an array to a query using a WHERE clause

Below is the method I have used, using PDO with named placeholders for other data. To overcome SQL injection I am filtering the array to accept only the values that are integers and rejecting all others.

$owner_id = 123;
$galleries = array(1,2,5,'abc');

$good_galleries = array_filter($chapter_arr, 'is_numeric');

$sql = "SELECT * FROM galleries WHERE owner=:OWNER_ID AND id IN ($good_galleries)";
$stmt = $dbh->prepare($sql);
$stmt->execute(array(
    "OWNER_ID" => $owner_id,
));

$data = $stmt->fetchAll(PDO::FETCH_ASSOC);

How to listen for 'props' changes

For me this is a polite solution to get one specific prop(s) changes and create logic with it

I would use props and variables computed properties to create logic after to receive the changes

export default {
name: 'getObjectDetail',
filters: {},
components: {},
props: {
  objectDetail: { // <--- we could access to this value with this.objectDetail
    type: Object,
    required: true
  }
},
computed: {
  _objectDetail: {
    let value = false
    // ...
    // if || do || while -- whatever logic
    // insert validation logic with this.objectDetail (prop value)
    value = true
    // ...
    return value 
  }
}

So, we could use _objectDetail on html render

<span>
  {{ _objectDetail }}
</span>

or in some method:

literallySomeMethod: function() {
   if (this._objectDetail) {
   ....
   }
}

How to use MySQLdb with Python and Django in OSX 10.6?

Run this command

sudo pip install mysql-python;

now you can run your command.

python manage.py startapp filename;

ActiveXObject is not defined and can't find variable: ActiveXObject

ActiveXObject is available only on IE browser. So every other useragent will throw an error

On modern browser you could use instead File API or File writer API (currently implemented only on Chrome)

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

I'm not sure there is an event handle for this, so you would have to keep a copy of the DOM and compare to the existing DOM in some kind of polling loop - which could be quite nasty. Firebug does this though - if you inspect the HTML and run some DOM-changes, it highlights the changes in yellow in the Firebug console for a short time.

Alternatively, you could create a remove function...

var removeElements = function(selector) {
    var elems = jQuery(selector);

    // Your code to notify the removal of the element here...
    alert(elems.length + " elements removed");

    jQuery(selector).remove();
};

// Sample usage
removeElements("#some-element");
removeElements("p");
removeElements(".myclass");

Maven Run Project

See the exec maven plugin. You can run Java classes using:

mvn exec:java -Dexec.mainClass="com.example.Main" [-Dexec.args="argument1"] ...

The invocation can be as simple as mvn exec:java if the plugin configuration is in your pom.xml. The plugin site on Mojohaus has a more detailed example.

<project>
    <build>
        <plugins>
            <plugin>
                <groupId>org.codehaus.mojo</groupId>
                <artifactId>exec-maven-plugin</artifactId>
                <version>1.2.1</version>
                <configuration>
                    <mainClass>com.example.Main</mainClass>
                    <arguments>
                        <argument>argument1</argument>
                    </arguments>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

How do I make an input field accept only letters in javaScript?

Try this:

var alphaExp = /^[a-zA-Z]+$/;
            if(document.myForm.name.match(alphaExp))
            {
                //Your logice will be here.
            }
            else{
                alert("Please enter only alphabets");
            }

Thanks.

How to set a parameter in a HttpServletRequest?

From your question, I think what you are trying to do is to store something (an object, a string...) to foward it then to another servlet, using RequestDispatcher(). To do this you don't need to set a paramater but an attribute using

void setAttribute(String name, Object o);

and then

Object getAttribute(String name);

How to align entire html body to the center?

If I have one thing that I love to share with respect to CSS, it's MY FAVE WAY OF CENTERING THINGS ALONG BOTH AXES!!!

Advantages of this method:

  1. Full compatibility with browsers that people actually use
  2. No tables required
  3. Highly reusable for centering any other elements inside their parent
  4. Accomodates parents and children with dynamic (changing) dimensions!

I always do this by using 2 classes: One to specify the parent element, whose content will be centered (.centered-wrapper), and the 2nd one to specify which child of the parent is centered (.centered-content). This 2nd class is useful in the case where the parent has multiple children, but only 1 needs to be centered). In this case, body will be the .centered-wrapper, and an inner div will be .centered-content.

<html>
    <head>...</head>
    <body class="centered-wrapper">
        <div class="centered-content">...</div>
    </body>
</html>

The idea for centering will now be to make .centered-content an inline-block. This will easily facilitate horizontal centering, through text-align: center;, and also allows for vertical centering as you shall see.

.centered-wrapper {
    position: relative;
    text-align: center;
}
.centered-wrapper:before {
    content: "";
    position: relative;
    display: inline-block;
    width: 0; height: 100%;
    vertical-align: middle;
}
.centered-content {
    display: inline-block;
    vertical-align: middle;
}

This gives you 2 really reusable classes for centering any child inside of any parent! Just add the .centered-wrapper and .centered-content classes.

So, what's up with that :before element? It facilitates vertical-align: middle; and is necessary because vertical alignment isn't relative to the height of the parent - vertical alignment is relative to the height of the tallest sibling!!!. Therefore, by ensuring that there is a sibling whose height is the parent's height (100% height, 0 width to make it invisible), we know that vertical alignment will be with respect to the parent's height.

One last thing: You need to ensure that your html and body tags are the size of the window so that centering to them is the same as centering to the browser!

html, body {
    width: 100%;
    height: 100%;
    padding: 0;
    margin: 0;
}

Fiddle: https://jsfiddle.net/gershy/g121g72a/

Primitive type 'short' - casting in Java

Given that the "why int by default" question hasn't been answered ...

First, "default" is not really the right term (although close enough). As noted by VonC, an expression composed of ints and longs will have a long result. And an operation consisting of ints/logs and doubles will have a double result. The compiler promotes the terms of an expression to whatever type provides a greater range and/or precision in the result (floating point types are presumed to have greater range and precision than integral, although you do lose precision converting large longs to double).

One caveat is that this promotion happens only for the terms that need it. So in the following example, the subexpression 5/4 uses only integral values and is performed using integer math, even though the overall expression involves a double. The result isn't what you might expect...

(5/4) * 1000.0

OK, so why are byte and short promoted to int? Without any references to back me up, it's due to practicality: there are a limited number of bytecodes.

"Bytecode," as its name implies, uses a single byte to specify an operation. For example iadd, which adds two ints. Currently, 205 opcodes are defined, and integer math takes 18 for each type (ie, 36 total between integer and long), not counting conversion operators.

If short, and byte each got their own set of opcodes, you'd be at 241, limiting the ability of the JVM to expand. As I said, no references to back me up on this, but I suspect that Gosling et al said "how often do people actually use shorts?" On the other hand, promoting byte to int leads to this not-so-wonderful effect (the expected answer is 96, the actual is -16):

byte x = (byte)0xC0;
System.out.println(x >> 2);

Deprecated Gradle features were used in this build, making it incompatible with Gradle 5.0

Solution for the issue: deprecated gradle features were used in this build making it incompatible with gradle 6.0. android studio This provided solution worked for me.

First change the classpath in dependencies of build.gradle of your project From: classpath 'com.android.tools.build:gradle:3.3.1' To: classpath 'com.android.tools.build:gradle:3.6.1'

Then make changes in the gradle-wrapper.properties file this file exists in the Project's gradle>wrapper folder From: distributionUrl=https\://services.gradle.org/distributions/gradle-5.4.1-all.zip To: distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.4-all.zip

Then Sync your gradle.

Selecting text in an element (akin to highlighting with your mouse)

You can use the following function to select content of any element:

jQuery.fn.selectText = function(){
    this.find('input').each(function() {
        if($(this).prev().length == 0 || !$(this).prev().hasClass('p_copy')) { 
            $('<p class="p_copy" style="position: absolute; z-index: -1;"></p>').insertBefore($(this));
        }
        $(this).prev().html($(this).val());
    });
    var doc = document;
    var element = this[0];
    console.log(this, element);
    if (doc.body.createTextRange) {
        var range = document.body.createTextRange();
        range.moveToElementText(element);
        range.select();
    } else if (window.getSelection) {
        var selection = window.getSelection();        
        var range = document.createRange();
        range.selectNodeContents(element);
        selection.removeAllRanges();
        selection.addRange(range);
    }
};

This function can be called as follows:

$('#selectme').selectText();