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Asked: 2020-03-30 19:40:44 +0800 CST 2020-03-30 19:40:44 +0800 CST

Problems getting a value in PHP

  • 772

In my PHP code I obtain the value of an input but what I want to do is give it a value in the event that said value does not exist, by default the inputs do not have any value and it correctly collects the data in the variables when I place something but I don't know how to check when there is nothing to give it another value, I did it this way but apparently it is not this way so I would like to know what I have to do.

if(is_null($nombre)) {
   $nombre = $lista['nombre'];
}
php

3 Answers

  1. Best Answer

    With PHP 7, you can use theNULL COALESCENCE OPERATOR

    $nombre = $lista['username'] ?? 'Sin valor asignado';

    Where:

    • The variable $nombreis equal to '$list['username']'
    • In case of not receiving the previous value, with the double sign of ??we assign a default value that is:Sin valor asignado
    • This operator is similar in function and length to the ternary operator
    • In this case you can avoid the use of the functionisset()

    EXAMPLE 1

    <?php

$lista['username'];

$nombre = $lista['username'] ?? 'Sin valor asignado';

echo $nombre;

    he's going to give me back

    no value assigned

    EXAMPLE 2

    <?php

$lista['username'] = "Pedro";

$nombre = $lista['username'] ?? 'Sin valor asignado';

echo $nombre;

    give me back

    Pedro

    Operator Reference

    • 3

  2. I leave you an example of how to add a simple name to the database:

    The first thing I use is issetthat it determines if a variable is defined, more in php.net and then I use emptythat it determines if a variable is empty, more info in php.net .

    You will not be able to enter anything to the database until you complete the name field and for more security I use PDO- Prepared Statements .

    <?php
if(isset($_POST['agregar'])){
    if(!empty($_POST['nombre'])){
        $add = $conn->prepare("INSERT INTO usuario (nombre) VALUES (:usuario)");
        $add->bindValue(':usuario', $_POST['nombre']);
        $add->execute();

        echo 'Usuario agregado con exito'; 
    }
    else{
        echo 'No se pudo agregar el usuario - campos vacios';
    }
}
?>

<form action="" method="post">
<input type="text" name="nombre" placeholder="Nombre">
<button name="agregar">Agregar</button>
</form>

    I hope I've helped!

    • 2 
  3. $variable = (isset($_GET['parametro']) ? $_GET['parametro'] : "algo por defecto" ;
    • 1