do something here if 'keyShouldBeSet' is not set This behavior is more problematic than it might appear at first and is a common source of problems.Ĭonsider the following: $data = fetchRecordFromStorage($storage, $identifier) Unset($value) // $value no longer references $arrĬommon Mistake #2: Misunderstanding isset() behaviorĭespite its name, isset() not only returns false if an item does not exist, but also returns false for null values. To still get the benefit of using references in foreach loops without running the risk of these kinds of problems, call unset() on the variable, immediately after the foreach loop, to remove the reference e.g.: $arr = array(1, 2, 3, 4) Pass 3: Copies $array (which now equals “2”) into $value (which is a reference to $array), so $array still equals 2.Pass 2: Copies $array (i.e., “2”) into $value (which is a reference to $array), so $array now equals 2.Pass 1: Copies $array (i.e., “1”) into $value (which is a reference to $array), so $array now equals 1.As a result, here’s what happens during each step of the second foreach loop: Specifically, since $value is now being accessed by value (i.e., by copy), foreach copies each sequential $array element into $value in each step of the loop. The last value on the last line is indeed a 2, not a 3.Īfter going through the first foreach loop, $array remains unchanged but, as explained above, $value is left as a dangling reference to the last element in $array (since that foreach loop accessed $value by reference).Īs a result, when we go through the second foreach loop, “weird stuff” appears to happen. The above code will output the following: 1,2,3 Here’s an example of the kind of evasive and confusing bugs that this can lead to: $array = įoreach ($array as &$value) // by value (i.e., copy) After the loop completes, therefore, $value still points to the last element of $array and remains in scope. On each iteration foreach sets the reference to point to the next element of $array. Thus, $value in the above example is a reference within the top scope of the script. The main thing to remember is that foreach does not create a scope. Subsequent operations involving $value could therefore unintentionally end up modifying the last element in the array. Specifically, in the above example, after the code is executed, $value will remain in scope and will hold a reference to the last element in the array. The problem is that, if you’re not careful, this can also have some undesirable side effects and consequences. Not sure how to use foreach loops in PHP? Using references in foreach loops can be useful if you want to operate on each element in the array that you are iterating over. Common Mistake #1: Leaving dangling array references after foreach loops This article highlights ten of the more common mistakes that PHP developers need to beware of. But its ease of use notwithstanding, PHP has evolved into quite a sophisticated language with many frameworks, nuances, and subtleties that can bite developers, leading to hours of hair-pulling debugging. DeSantis called the course, which included lessons on Black queer theory and the prison abolition movement, "indoctrination.PHP makes it relatively easy to build a web-based system, which is much of the reason for its popularity. "It is disappointing, but nevertheless unsurprising, that critics would reduce months of work to create Florida's first ever stand-alone strand of African American History Standards to a few isolated expressions without context," the pair said.Įarlier this year, Florida rejected a proposed advanced placement course that would have focused on African American studies. Florida students deserve to learn how slaves took advantage of whatever circumstances they were in to benefit themselves and the community of African descendants."Īllen and Rice said that the curriculum provides "comprehensive and rigorous instruction on African American History." "Any attempt to reduce slaves to just victims of oppression fails to recognize their strength, courage and resiliency during a difficult time in American history. Frances Presley Rice, members of the group, before listing examples like Crispus Attucks and Booker T. This is factual and well documented," said Dr. "The intent of this particular benchmark clarification is to show that some slaves developed highly specialized trades from which they benefitted. Democrats like Kamala Harris have to lie about Florida's educational standards to cover for their agenda of indoctrinating students and pushing sexual topics onto children.įlorida stands in their way and we will continue to expose their agenda and their lies.- Ron DeSantis July 21, 2023
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