In practice, however, you will find foreach loops and list()/ each() loops in about equal proportions, despite the latter option being slower. There are times where its ok to have a foreach within a while, but this isnt one of them. Generally speaking, using foreach loops is the most optimised way to loop through an array, and is also the easiest to read.
There is a lot more detail on array cursors later. The meaning of that first line is "get the current element in the array, and assign its key to $var and its value to $val, then advance the array cursor. To start with, each() will return the first element, then the second element, then the third, and so on, until it finds there are no elements left, in which case it will return false and end the loop. All arrays have a cursor, and you can freely move it around - it is used in the while loop above, where we need to iterate through an array.
I need the while loop to continue looping. Because the foreach loop does leaves the block when values have been iterated. "Array cursor" is the technical term for the element of an array that is currently being read. convert foreach into while loop Ask Question Asked 12 years ago Modified 12 years ago Viewed 4k times 2 Hi guys i need to convert a foreach loop into a while loop. Each() takes an array as its parameter, and returns the current key and value in that array before advancing the array cursor. List() is a function that does the opposite of array() - it takes an array, and converts it into individual variables. The second way to use foreach does allow you to extract keys, and looks like this:Īnother commonly used way to loop over arrays is using the list() and each() functions, like this: In this situation, the array keys are ignored completely, which usually makes most sense when they have been auto-generated (i.e. Here the array $array is looped through and its values are extracted into $val. The easiest way to use foreach looks like this: However, there is a quick and easy way to accomplish the same thing: a foreach loop, which itself has two versions.
While loop in foreach php code#
As a result, code like this should generally be avoided: That is, it can have its keys out of order or entirely missing. The first part of the code in the while () loop is defining some variables. I think the problem is not the foreach ()/while () but in what you are doing with the. Theres a site that has a lot of performance tests on various functions in PHP that do similar things, such as for vs. For example, an array may have keys 0, 1, 2, 5, 3, 6, 7. You simply put a foreach () within a while () loop. However, these numbers cannot be guaranteed to exist within the array in any given order, or even to exist at all - they are just key values themselves. Why We Need Loops: A Simple ExampleĬonsider the following need: “I want to write a function that prints out integers in sequence, beginning with 0 and going up to any number.If you do not specify a key, as in the first example, PHP will just assign incrementing numbers starting with 0. To code these sorts of repeated tasks in PHP, loops are pretty much the only game in town. In programming, this might be “for each user in the WordPress database: retrieve that user’s username, continuing until all usernames have been retrieved.” Or literally zillions of other examples. In life, this might be “for each dish in the sink: soap, scrub, and rinse the dish, then put it in the drying rack, continuing until the sink is empty.” Or literally zillions of other examples. In programming, as in life, an extremely common need is to do a similar thing over and over again. A common need in programming is to repeat a similar action multiple times.
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