Use built-in functions to solve PHP multi-dimensional array sorting problems

Use built-in functions to solve PHP multi-dimensional array sorting problems_PHP tutorial

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Release： 2016-07-15 13:27:29

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When learning PHP, you may encounter the problem of sorting multi-dimensional arrays in PHP. Here we will introduce the solution to the problem of sorting multi-dimensional arrays in PHP. I will share it with you here. I hope it will be helpful to everyone.

Compare the size and sort according to the keys of the array. Needless to say, PHP has many convenient built-in functions, krsort(), ksort() If you compare the size based on the value of the array, it will be more troublesome. If there are no duplicate values, you can first use array_flip() to exchange keys and values; then krsort(), and then exchange them back in array_flip() to compare the sizes. If there are duplicate values, some sorting algorithms must be used. However, PHP has a very convenient callback function uasort() that will maintain the original index and usort() that will rebuild the index. PHP multidimensional array sorting code:

<ol class="dp-xml">
<li class="alt"><span><span class="tag"></span><span class="tag-name">php</span><span> </span></span></li>
<li class=""><span>functioncmp($a,$b){  </span></li>
<li class="alt"><span>if($a[”nums”]==$b[”nums”]){  </span></li>
<li class=""><span>return0;  </span></li>
<li class="alt"><span>}  </span></li>
<li class="">
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</li>
<li class="">
<span>“username”=</span><span class="tag">></span><span>owen,  </span>
</li>
<li class="alt">
<span>“nums”=</span><span class="tag">></span><span>2,  </span>
</li>
<li class=""><span>),  </span></li>
<li class="alt">
<span></span><span class="attribute">1</span><span>=</span><span class="tag">></span><span>Array(  </span>
</li>
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<span>“username”=</span><span class="tag">></span><span>d5s,  </span>
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<span>“nums”=</span><span class="tag">></span><span>5,  </span>
</li>
<li class=""><span>),  </span></li>
<li class="alt">
<span></span><span class="attribute">2</span><span>=</span><span class="tag">></span><span>Array(  </span>
</li>
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</li>
<li class="alt">
<span>“nums”=</span><span class="tag">></span><span>3,  </span>
</li>
<li class=""><span>),  </span></li>
<li class="alt"><span>);  </span></li>
<li class=""><span>uasort($arr,“cmp”);  </span></li>
<li class="alt">
<span>echo‘</span><span class="tag"><</SPAN><SPAN class=attribute>prestyle</SPAN><SPAN class=tag-name>prestyle</SPAN><SPAN>=”text-align:left”</SPAN><SPAN class=tag>></span><span>’;  </span>
</li>
<li class=""><span>print_r($arr);  </span></li>
<li class="alt">
<span>echo‘</span><span class="tag"><span class="tag-name">pre</span><span class="tag">></span><span>’;  </span></span>
</li>
<li class="">
<span></span><span class="tag">?></span><span> </span>
</li>
<li class="alt"><span> </span></li>
<li class=""><span>Array  </span></li>
<li class="alt"><span>(  </span></li>
<li class="">
<span>[0]=</span><span class="tag">></span><span>Array  </span>
</li>
<li class="alt"><span>(  </span></li>
<li class="">
<span>[username]=</span><span class="tag">></span><span>owen  </span>
</li>
<li class="alt">
<span>[nums]=</span><span class="tag">></span><span>2  </span>
</li>
<li class=""><span>)  </span></li>
<li class="alt"><span> </span></li>
<li class="">
<span>[2]=</span><span class="tag">></span><span>Array  </span>
</li>
<li class="alt"><span>(  </span></li>
<li class="">
<span>[username]=</span><span class="tag">></span><span>pt  </span>
</li>
<li class="alt">
<span>[nums]=</span><span class="tag">></span><span>3  </span>
</li>
<li class=""><span>)  </span></li>
<li class="alt"><span> </span></li>
<li class="">
<span>[1]=</span><span class="tag">></span><span>Array  </span>
</li>
<li class="alt"><span>(  </span></li>
<li class="">
<span>[username]=</span><span class="tag">></span><span>d5s  </span>
</li>
<li class="alt">
<span>[nums]=</span><span class="tag">></span><span>5  </span>
</li>
<li class=""><span>)  </span></li>
<li class="alt"><span> </span></li>
<li class=""><span>) </span></li>
</ol>

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