Best practices in web development: use of empty

The empty() function in PHP is used to check if a variable exists and if its value is considered empty. It’s a good practice to make your code not break when you receive variable values that you have to secure

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Return true if the variable does not exist or if its value is one of the following:

• “” (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)

Since empty checks that the variable exists, it would save us this statement:

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if ( isset( $order['client_name'] ) && '' !== $order['client_name'] )

To this one which is much more abbreviated:

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if ( ! empty( $order['client_name'] )

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if ( isset( $order( $order['client_name'] ) && ! empty( $order['client_name'] ) )

For an array we should also add the check if it's an array:

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if ( ! empty( $order ) && is_array( $order ) )

And you could also use it in a ternary:

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$client_name = ! empty( $order['client_name'] ) ? $order['client_name'] : '';

But in these cases, it is customary to use isset:

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$client_name = isset( $order['client_name'] ) ? $order['client_name'] : '';

The empty() function is commonly used in control flow structures, such as if and while, to check if a variable has a valid value before performing an action or making a decision based on that value. It can also be used in web forms to check whether or not a field has been filled in before processing the data submitted by the user.