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PHP

Posted by Daniele Vicinanzo
Daniele Vicinanzo
21,277 Points

php basics, some things that i lost

i would understand better some things that in the videos i don't understood very well

1: stripos

2: isset

3: $_POST, GET and SERVER (SERVER REQUEST, i don't remember well)

4: trim

5: the difference between include, include_once, require, require_once

6: how to use -> (not => i got the array key)

7: where i need to use exit; because in general in js you use break for exemple in the infinite loops but i saw in some videos here of php basics that exit is used also outside of a loop to break something, i'm a bit confused because i guess that a function or a statement stop if it is not an infinite loop and i need the exit only where it needs

1 Answer

Codin - Codesmite
Codin - Codesmite
8,600 Points
Codin - Codesmite
Codin - Codesmite
8,600 Points

stripos()

The stripos() function finds the position of the first occurrence of a string inside another string.

For example: 

<?php
echo stripos("This is an example!, example");
?>

This will return 11 as the string "example" starts at the 11th character in the string (The "T" in "This" is position 0).

You also have;

strripos() - Finds the position of the last occurrence of a string inside another string.

strpos() - Finds the position of the first occurrence of a string inside another string.

strrpos() - Finds the position of the last occurrence of a string inside another string.

strpos(), strrpos() and striipos() are case-sensitive whereas stripos() is case-insensitive.

isset()

The isset() function checks to see if a variable is set and is not NULL.

For example:

<?php
$test = 10;
if (isset($test)){
  echo "Test1 is set to " . $test;
}
else {
  echo "Test1 Is not set";
}


if (isset($test2)){
  echo " Test 2 is set to " . $test2;
}
else {
  echo " Test2 is not set";
}
?>

This will return "Test1 is set to 10 Test2 is not set" as Test1 is set to 10 and test2 has not been set.

$_POST, $_GET, $_SERVER

PHP superglobals $_POST and $_GET are used to collect form data.

For example:

Your Form

<html>
<body>

<form action="welcome.php" method="post">
Name: <input type="text" name="name"><br>
E-mail: <input type="text" name="email"><br>
<input type="submit">
</form>

</body>
</html>

The data submitted in your form can be called from welcome.php like so:

<html>
<body>

Welcome <?php echo $_POST["name"]; ?><br>
Your email address is: <?php echo $_POST["email"]; ?>

</body>
</html>

$_GET is an array of variables passed to the current script via the URL parameters.

$_POST is an array of variables passed to the current script via the HTTP POST method.

$_SERVER is an array containing information such as headers, paths, and script locations. The entries in this array are created by the web server.

<?php echo var_dump($_SERVER); ?>

Will return the information contained in the array but not all webservers will return information or all of the information due to security settings.

trim()

trim() is a function used to remove whitespace from both sides of a string.

For example:

<?php
$example ="  This example contains white space at the start and end!  ";
echo trim($example);
?>

Will return "This example contains white space at the start and end!" rather than " This example contains white space at the start and end! " as trim() removed the white space from the start and end.

include, include_once, require, require_once

include and include_once will continue running the code if the include file is missing, where as requrie and require_once will exit if the file is missing as it is required to run the application.

require_once and include_once will only allow the file to be included or required once where as include and require allow you to include and require the file multiple times.

->

"->" Is used when reffering to a member of a PHP object.

exit()

exit() function is an alias for die() both stop the current script and can have a message returned.

For example:

<?php
echo "First String, ";
exit("The Second String will not be displayed as the script has been stopped!");
echo "Second String";
?>

Will display "First String, The Second String will not be displayed as the script has been stopped!".

Hope this helps :)

Daniele Vicinanzo
Daniele Vicinanzo
21,277 Points

Thanks :)