PHP 5 Recipes A Problem-Solution Approach PHẦN 4

Bây giờ chúng ta hãy mở rộng Bird để tạo ra một lớp Parrot. Bạn chỉ ra Parrot mở rộng chim bằng cách sử dụng kéo dài từ khóa như sau. Điều này có nghĩa là Parrot được thừa hưởng tất cả các thuộc tính và phương pháp của Bird. | 182 4-39 REVERSING AN ARRAY USING KRSORT 4-39. Reversing an Array Using krsort The krsort function sorts an array by key in reverse order. The Code php dogs array Lassie Collie Bud Sheepdog Rin-Tin-Tin Alsatian Snoopy Beagle krsort dogs printf pre s pre n var_export dogs TRUE array Snoopy Beagle Rin-Tin-Tin Alsatian Lassie Collie Bud Sheepdog As you can see krsort preserves the relationship between keys and values. 4-40. Reversing an Array Using array_reverse The array_reverse function does just what you would expect it reverses the order in which the elements of an array are listed. The Code php dogs array Lassie Collie Bud Sheepdog Rin-Tin-Tin Alsatian Snoopy Beagle array_reverse dogs printf pre s pre n var_export dogs TRUE nums array 15 -4 0 array_reverse nums printf pre s pre n var_export nums TRUE Like the array sorting functions array_reverse works on an array in place. It leaves all key value associations intact. array Lassie Collie Bud Sheepdog Rin-Tin-Tin Alsatian 4-41 RANDOMIZING AN ARRAY USING SHUFFLE KSHUFFLE AND ARRAY_RAND 183 Snoopy Beagle array 0 15 1 2 -4 3 4 0 4-41. Randomizing an Array Using shuffle kshuffle and array_rand To reorder an array s elements so they are in random order PHP provides the shuffle function. Like the sort functions shuffle acts on the array in place and can be called repeatedly without obtaining the same result over and over as shown in the next example. The Code php nums array 15 -4 0 shuffle nums printf pre s pre n var_export nums TRUE shuffle nums printf pre s pre n var_export nums TRUE shuffle nums printf pre s pre n var_export nums TRUE Some example output follows. You should keep in mind that if you run the same code on your own PHP installation the results will be similar but almost certainly not identical to this array 0 1 -4 2 0 3 4 15 array 0 0 1 -4 184 4-42 SORTING AN ARRAY USING COMPARISON FUNCTIONS 2 3 4 15 array 0 15 1 2 -4 3 4 0 4-42. Sorting an Array Using .