![]() 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. In Example 1.PHP makes it relatively easy to build a web-based system, which is much of the reason for its popularity. Let us look at how we may use this modifier in our Antlers templates. This will let us structure our inserted content differently within our template.įinally, on line 42, we return all items, including all inserted content. The vital thing to note on line 36 is that we are assigning a different type value for our inserted content. ![]() We use the splice method to perform the actual insertion of our additional content. On line 31, we calculate a random index to insert our other content. The actual insertion of our additional content happens between lines 28 and 40. We are using another Statamic collection here, but the source of our additional content could be anything from multiple collections to the results of some external API. We account for this between lines 21 and 23.īetween lines 25 and 27, we are retrieving random entries from our pages collection up to our total number of items to insert. For example, if we had four blog posts, this logic would ensure we only insert one piece of supplementary content.īecause our total number of items to insert is dynamic, it may be zero. Our example will limit the number of inserted posts to 25% of the total number of blog posts. This logic can be adjusted to suit your project's specific needs. On line 19, we are calculating the total amount of random items we want to insert into our list of blog posts. ![]() This will behave similarly to the as modifier and allow us to differentiate between our original blog posts and our inserted content. Between lines 12 and 17, we convert all our blog posts into a nested array. In total, there are nine variables that Antlers will make available to us for every array that we loop over:īefore we look at the Antlers template, let us spend some time discussing what our modifier is accomplishing in Example 1.78. These variables can help us determine our position within the array, whether or not the current element is the first or last element, quickly access neighboring elements and more. In addition to the value variable, Antlers will add several additional variables for us automatically. This behavior means we do not have to introduce unnecessary boilerplate code or temporary variables to render a list of items on our site. The critical thing to notice when iterating Antlers arrays is that, by default, all the content that appears between our opening and closing tag repeats for each element in the array. We do this within our template on line 3 to produce the three elements in our output. When we have simple arrays, such as the one in Example 1.1, that contain no key/value pairs, we can use the variable named value to retrieve the contents of each element in the list. For example, on line 2, we have, which closes our tag pair. The template in Example 1.2 contains our variable "tag pair." When we want to iterate over an array, our tag pair will have the variable name as both the opening and closing tag names. Our data in Example 1.1 contains an array named items which includes a list of three strings.
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