PHP object property from class variable? [duplicate]

Question

Why does this work

foreach ($items as $i) {
    $dataTitle = $this->dataTitle;
    $title = $i->$dataTitle;
}

when this doesn't?

foreach ($items as $i) {
    $title = $i->$this->dataTitle;
}

Is there a better way to do this?

Answer 1

Try this:

$title = $i->{$this->dataTitle};

Your expression is being parsed as:

$title = ($i->$this)->dataTitle;

Answer 2

$this referes to current object parsed in not obvious order. You need to use {expr} notation, to dynamicly evaluate property name.

Try to use {} around $this->dataTitle:

$title = $i->{$this->dataTitle};

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Look at bottom part of last example in variable variables section of manual.