修复php警告：偏移量类型错误

Question

I'm getting "illegal offset type" error for every iteration of this code. Here's the code in case anyone can help:

if ( ! empty( $display_args['allowed_tags'] ) ) {
    $allowed_tags = [];

    foreach ( $display_args['allowed_tags'] as $tag ) {
        $allowed_tags[ $tag ] = array();
    }

    print_r($allowed_tags);
}

Any ideas. Thanks in advance.

Answer 1

At some point of the iteration, $tag of $allowed_tags[ $tag ] is invalid for use as an array key.

For example, try executing:

<?php
$a[ array() ] = 'hello';

And you will get:

Warning: Illegal offset type in {{filepath}} line 2

So, you cannot blindly use $tag like that.

---

Update per comment:

For debugging you can use is_scalar() to see if a value is valid for use as an array key:

if ( ! empty( $display_args['allowed_tags'] ) ) {
    $allowed_tags = [];

    foreach ( $display_args['allowed_tags'] as $tag ) {
        if( is_scalar( $tag ) ) {
            $allowed_tags[ $tag ] = array();
        }
        else {
            echo 'cannot use!';
            var_dump( $tag );
            echo '<br>';
        }
    }

    print_r($allowed_tags);
}