Web Technology Experts Notes

Showing posts with label php problem solutions. Show all posts

Saturday, 18 April 2020

How to check if a number is prime?

Question: What is Prime Number
A prime number is a natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers.

Question: Give the example of Prime Number
2, 3, 5, 7, 11, 13, 17, 19, 23 and 29.

Question: Write an function that check the prime number OR Not?

function checkPrime($number){
    if($number < 0 ){
        return false;
    }
    $return=true;
    for($i=2; $i < $number; $i++){
        if($number % $i ==0){
            $return=false;
            break;
        }
    }
   return $return;
}

Question: How to check a number is prime Or Not?

echo checkPrime(2)?'Prime':'Not Prime'; //Prime
echo checkPrime(4)?'Prime':'Not Prime'; //Not Prime
echo checkPrime(6)?'Prime':'Not Prime'; //Not prime
echo checkPrime(7)?'Prime':'Not Prime';  //Prime

Question: What are the prime numbers between 1 to 100?

for( $i = 2; $i < 100; $i++ ){
    if( checkPrime( $i ) ){
        echo $i;
        echo ',';
    }
}

Sunday, 29 March 2020

General error: 1364 Field city_id doesn't have a default value

I have upgraded the MySQL from 5.5 to 5.6 and then getting below type of errors.
General error: 1364 Field 'city_id' doesn't have a default value

(I was not getting such type of error, it must come after upgrading my MySQL Version from 5.5 to 5.6)

Solution: It have 3 Solutions

In Your Code (PHP), always set a default value (if no value) before save.

$objSaveData->saveData(
    array(
        'id'=>111,
        'name'=>'New user',
        'city_id'=>0, //default value
    );
);

Create fields with default values set in datatable. It could be empty string, which is fine for MySQL server running in strict mode.
like below:
```
ALTER TABLE `users` CHANGE `city_id` `city_id` INT(10) UNSIGNED NOT NULL DEFAULT '0';
```
Disable MySQL Strict Mode (Most appropriate)
Disable it by setting your own SQL_MODE in the my.cnf file, then restart MySQL.

Look for the following line:
```
sql-mode = "STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION"
```
Change it to:
```
sql-mode="" 
```
Restart the MySQL Service.

Saturday, 21 December 2019

What are special characters? and how to remove special characters?

Question: What are special characters?
Special characters are selected punctuation characters present on standard US keyboard.

Question: Provide list of special characters?

Character	Name
	Space
!	Exclamation
"	Double quote
#	Number sign (hash)
$	Dollar sign
%	Percent
&	Ampersand
'	Single quote
(	Left parenthesis
)	Right parenthesis
*	Asterisk
+	Plus
,	Comma
-	Minus
.	Full stop
/	Slash
:	Colon
;	Semicolon
<	Less than
=	Equal sign
>	Greater than
?	Question mark
@	At sign
[	Left bracket
\	Backslash
]	Right bracket
^	Caret
_	Underscore
`	Grave accent (backtick)
{	Left brace
\|	Vertical bar
}	Right brace
~	Tilde

Question: How to remove special characters from string including space?

$string='test !@#ing';
echo preg_replace('/[^A-Za-z0-9\-]/', '', $string);

Question: How to remove special characters from string except space?

$string='test !@#ing';
echo preg_replace('/[^A-Za-z0-9\-\s]/', '', $string);

Question: How to replace special characters with hyphen?

$string='test !@#ing';
echo preg_replace('/[^A-Za-z0-9\-\s]/', '-', $string);

Question: How to replace multiple hyphen with single hyphen?

$string='test-----ing';
echo preg_replace('/-+/', '-',$string);

Question: How to remove special characters from array?

$array=array('test !@#ing','sdalkjsad','#$#33');
function cleanData($string){
return preg_replace('/[^A-Za-z0-9\-]/', '', $string);
}
$array = array_map('cleanData',$array);
print_r($array);

Question: How to remove all special characters from javascript?

var stringToReplace='test !@#ing';
stringToReplace=stringToReplace.replace(/[^\w\s]/gi, '')

Thursday, 12 December 2019

How to resize images in php

Function resizeImage

    
/**
 * 
 * @param type $width
 * @param type $height
 * @param type $mode
 * @param type $imageName
 * @param type $extension
 * @return string
 */
     function resizeImage($width, $height, $mode, $imageName,$extension) {
        $docRoot = getenv("DOCUMENT_ROOT");
        
        /* Get original image x y */
        $tmpNM = $_FILES['files']['tmp_name'];
        
        list($w, $h) = getimagesize($_FILES['files']['tmp_name']);
        /* calculate new image size with ratio */
        $ratio = max($width / $w, $height / $h);
        $h = ceil($height / $ratio);
        $x = ($w - $width / $ratio) / 2;
        $w = ceil($width / $ratio);
        /* new file name */
        if ($mode == 'userphoto') {
                $path = $docRoot . '/upload/userphoto/' . $imageName;
        } 
        
 
        /* read binary data from image file */
        $imgString = file_get_contents($_FILES['files']['tmp_name']);
        /* create image from string */
        $image = imagecreatefromstring($imgString);
        $tmp = imagecreatetruecolor($width, $height);
        imagecopyresampled($tmp, $image, 0, 0, $x, 0, $width, $height, $w, $h);
        $fileTypes = array('jpg', 'jpeg', 'jpe', 'png', 'bmp', 'gif'); // File extensions
        /* Save image */
        $extension = strtolower($extension);
        switch ($extension) {
            case 'jpg':
            case 'jpeg':
            case 'jpe':
                imagejpeg($tmp, $path, 100);
                break;
            case 'png':
                imagepng($tmp, $path,0);
                break;
            case 'gif':
                imagegif($tmp, $path, 100);
                break;
            case 'bmp':
                imagewbmp($tmp, $path);
                break;
            default:
                
                exit;
                break;
        }
        return $path;
        /* cleanup memory */
        imagedestroy($image);
       imagedestroy($tmp);
    }

How to use Code
HTML Code

<form action="upload.php" enctype="multipart/form-data" method="post">
<input id="image upload" name="files" type="file" />
<input name="submit" type="submit" value="Upload Image" />

PHP Code

  
//List of thumbnails
$sizes = array(200 => 200, 150 => 150);

$files=array();
if (!empty($_FILES)) {
    //Clean the image name
    $_FILES['files']['name'] = preg_replace('/[^a-zA-Z0-9_.-]/', '', strtolower(trim($_FILES['files']['name'])));    
    
    //Temporary file, type, name
    $tmpNM = $_FILES['files']['tmp_name'];
    $imageType = $_FILES['files']['type'];
    $imageName = $_FILES['files']['name'];
    
    //Get image extension
    $imageNameType = explode(".", $_FILES['files']['name']);
    
    //Type of images support for uploading
    $fileMimeTypes = array('image/jpeg', 'image/png', 'image/bmp', 'image/gif'); // mime  extensions
    $fileTypes = array('jpg', 'jpeg', 'jpe', 'png', 'bmp', 'gif'); // File extensions
    
    if (in_array(strtolower($imageNameType[1]), $fileTypes)) {
        $fullImageName = time('his') . '_' . $_FILES['files']['name'];
        foreach ($sizes as $w => $h) {
            $files[] = $this->resizeImage($w, $h, 'userphoto', "{$w}_{$fullImageName}", $imageNameType[1]);
        }

    } 
}

Saturday, 7 December 2019

How to Validate email address in PHP?

Following are in built PHP function to validate the email address and Ip Address.

Validate Email - Example 1

$email='helo@gmail.com';
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
  echo $email. ' - Invalid'; 
}else{
echo $email. ' - Valid';     
}

helo@gmail.com - Valid

Validate Email - Example 2

$email='464646@gmail.com';
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
  echo $email. '- Invalid'; 
}else{
echo $email. ' - Valid';     
}

464646@gmail.com - Valid

Validate Email - Example 3

$email='arunkumar.com';
if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
  echo $email. ' - Invalid'; 
}else{
echo $email. ' - Valid';     
}

arunkumar.com - Invalid

Validate IP Address - Example 1
Question: How to Validate IP Address?

$ipAddress = '127.0.0.1';
if (!filter_var($ipAddress, FILTER_VALIDATE_IP)) {
    echo "$ipAddress is In-valid.";
}else{
    echo "$ipAddress is Valid.";
}

127.0.0.1 is Valid

Validate IP Address - Example 2

$ipAddress = '127.test.0.0.1';
if (!filter_var($ipAddress, FILTER_VALIDATE_IP)) {
    echo "$ipAddress is In-valid.";
}else{
    echo "$ipAddress is In-Valid.";
}

127.test.0.0.1 is Valid

Validate URL - Example 1

$ipAddress = '127.test.0.0.1';
$website = 'https://www.web-technology-experts-notes.in';
if (!preg_match("/\b(?:(?:https?|ftp):\/\/|www\.)[-a-z0-9+&@#\/%?=~_|!:,.;]*[-a-z0-9+&@#\/%=~_|]/i",$website)) {
  echo   "Invalid URL";
}else{
echo   "Valid URL";
}

Valid URL