PHP simple array sorting method-PHP Tutorial-php.cn

PHP simple array sorting method

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Release： 2016-07-25 09:04:10

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$arr = array('100', '200', '300');

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The above code creates an array and contains 3 values. Numeric indexing of PHP arrays starts from 0. So the value of $arr[0] is 100. Values from one array can be copied to another array using a simple "=" sign. If you need to save numbers in ascending order into an array, you can use the range() function to automatically create the array. The following code will create an array of numbers from 1 to 10:

$nums = range(1,10);

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This function also has a third parameter, which can set the step size of the number increase. For example: range(1,10,2) is an odd number between 1 and 10. PHP also supports associative arrays, which can associate variable values with keywords. like:

$arr = array('one'=>100, 'two'=>200, 'three'=>300);

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2. Array sorting 1. sort() function: Sort the array value in ascending alphabetical or numerical order. The sort() function is case-sensitive, all uppercase letters precede lowercase letters. This function also has a second parameter, which can be passed SORT_NUMERIC or SORT_STRING or SORT_REGULAR (default value). Specifying a sorting function is very useful. For example, when comparing the numbers 12 and 2, 12 is less than 2 from a string perspective, but the opposite is true from a numeric perspective.

2. asort() function, ksort() function: If an associative array is used, the ordering of keys and values must remain consistent after sorting. These two functions are needed. ksort is to sort by key (keyword), and asort is to sort by value (both in ascending order). For example, there is an array: $price = array('apple'=5,'banana'=6,'lychee'=7); We use ksort($price); the results after sorting are: lychees--7, apples--5, bananas--6 Using asort($price); the result after sorting is: Apple--5, Banana--6, Lychee--7 The corresponding reverse sorting is to add an 'r' in front of sort. That is, rsort(), arsort(), krsort()

3. Sorting of multi-dimensional arrays PHP knows how to compare two numbers or strings, but each element of a multidimensional array is an array. PHP doesn't know how to compare two arrays, so it needs to create a method to compare them.

>>> For more information, please view the complete list of php array sorting methods