Veteran talks about PHP array sorting_PHP tutorial

PHP is still relatively commonly used, so I studied PHP array sorting and shared it with you here. I hope it will be useful to everyone. After understanding usort custom sorting, let's take a look at sort(). This function can be said to be the originator of sorting functions in arrays. You must have found that all PHP array sorting functions have sort as the suffix. Function prototype: bool sort (array &array [, int sort_flags]) Description: Basically every function has an optional parameter, and sort is no exception. A convention specified by this optional parameter.

The optional types are as follows:
◆SORT_REGULAR - Normal comparison unit (does not change type) // Sort by ASCII value (B is greater than a)
◆SORT_NUMERIC - Unit is treated as a number Comparison //This parameter is commonly used for integers and floating point numbers
◆SORT_STRING – units are compared as strings
◆SORT_LOCALE_STRING – units are compared as strings according to the current locale settings

Let’s look at an example, from the help manual:

<ol class="dp-xml">
<li class="alt"><span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">php</span></font></strong><span> </span></span></li>
<li class="">
<span>$</span><span class="attribute"><font color="#ff0000">fruits</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">array</font></span><span>("lemon", "orange", "banana", "apple");  </span>
</li>
<li class="alt"><span>sort($fruits);  </span></li>
<li class="">
<span>foreach ($fruits as $</span><span class="attribute"><font color="#ff0000">key</font></span><span> =</span><span class="tag"><strong><font color="#006699">></font></strong></span><span> $val) {  </span>
</li>
<li class="alt"><span>echo "fruits[".$key."] = " . $val . "n";  </span></li>
<li class=""><span>}  </span></li>
<li class="alt">
<span></span><span class="tag"><strong><font color="#006699">?></font></strong></span><span> </span>
</li>
</ol>

The result of this PHP array sorting is as follows:

<ol class="dp-xml">
<li class="alt"><span><span>fruits[0] = apple  </span></span></li>
<li class=""><span>fruits[1] = banana  </span></li>
<li class="alt"><span>fruits[2] = lemon  </span></li>
<li class=""><span>fruits[3] = orange </span></li>
</ol>

You can find that it turns out to be lemon with index 0. After sorting again, it becomes apple. In order to keep the original keys/values ​​unchanged, you can replace sort() with asort(). In addition, these two functions arrange the keys in ascending order (a is in front of b). If you want to make it in descending order, just use rsort() instead. The corresponding arsort() maintains the original key/value correlation.

The following is a brief introduction to the ksort() function

This function is mainly used to sort associative arrays. , its "sister" function uksort() uses a custom function for comparison. In a word: ksort() for associative series, sorts the keys and preserves the association of key names to data. Natural sorting of arrays. The sorting functions we know so far either use the default way or sort in a custom way. Then natsort() uses a humanized sorting method to sort the array. I won’t go into details here. You can check the manual for examples. If you don’t have the PHP help manual on hand, you can check it out by browsing the online help manual on this site

<ol class="dp-xml">
<li class="alt"><span><span>shuffle（）//函数的使用  </span></span></li>
<li class=""><span>Shuffle()//用来对一个数组进行随机排序，这个有点像抽签，其他的就不多说了。到用的时候再看吧。  </span></li>
<li class="alt"><span>array_rand()//函数的使用  </span></li>
<li class=""><span>array_rand()//函数和shuffle（）差不多，也是随机返回数组中的元素，如下调用：  </span></li>
<li class="alt"><span>array_rand ( array [, int num_req] ) //可选参数指出你要返回的个数。 </span></li>
</ol>

At this point I think we have sorted the array. Now that I understand, if there are any "leftovers", I'll make up for it later.

http://www.bkjia.com/PHPjc/446529.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/446529.htmlTechArticlePHP is still relatively commonly used, so I studied PHP array sorting and shared it with you here. Hope it's useful to everyone. After understanding usort custom sorting, let’s...