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Learn more about how to use PHP array functions_PHP Tutorial

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Release： 2016-07-15 13:27:13
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PHP array functions are quite commonly used, so I studied the PHP array functions and shared them with you here. I hope it will be useful to everyone. Today we are learning about PHP array functions. Arrays are a data type that are used very frequently. Learning how to handle arrays will make it easier for you to build a website.

For example: Your website database contains Dali articles. Now you want to display 20 entertainment news titles on a page. These 20 After the article title is taken out from the database, do you want to use 20 variables to represent it? I don’t think you are that stupid, so what variables can be used to completely receive these 20 pieces of data? This requires the use of array variables. What is an array? An array is actually a data collection, which is equivalent to a data container. A lot of data is stored in it. We can save it in or take it out according to certain methods. We can also sort the data in it and other operations. We can also check whether there is any data in it. There is no data we want and so on.

1.array_multisort() to sort multiple arrays or multi-dimensional arrays can be used to sort multiple arrays at one time or to sort multi-dimensional arrays according to a certain dimension. The original key name association is retained during sorting, and the function implemented is similar to ORDERBY in SQL. 

<ol class="dp-xml">
<li class="alt"><span><span>$</span><span class="attribute"><font color="#ff0000">ar1</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">array</font></span><span>("10",100,100,"a");  </span></span></li>
<li class="">
<span>$</span><span class="attribute"><font color="#ff0000">ar2</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">array</font></span><span>(1,3,"2",1);  </span>
</li>
<li class="alt"><span>array_multisort($ar1,$ar2);  </span></li>
<li class="">
<span></span><span class="tag"><strong><font color="#006699">?></font></strong></span><span> </span>
</li>
<li class="alt"><span>//返回结果（保持了原来数组的关联性）  </span></li>
<li class="">
<span>$</span><span class="attribute"><font color="#ff0000">ar1</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">Array</font></span><span>([0]=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>10[1]=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>a[2]=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>100[3]=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>100)  </span>
</li>
<li class="alt">
<span>$</span><span class="attribute"><font color="#ff0000">ar2</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">Array</font></span><span>([0]=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>1[1]=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>1[2]=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>2[3]=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>3)  </span>
</li>
<li class=""><span> </span></li>
<li class="alt"><span>//实现学生成绩排名  </span></li>
<li class="">
<span>$</span><span class="attribute"><font color="#ff0000">grade</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">array</font></span><span>("score"=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>array(70,95,70.0,60,"70"),  </span>
</li>
<li class="alt">
<span>"name"=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>array("ZhangSan","LiSi","WangWu",  </span>
</li>
<li class=""><span>"ZhaoLiu","LiuQi"));  </span></li>
<li class="alt"><span>array_multisort($grade["score"],SORT_NUMERIC,SORT_DESC,  </span></li>
<li class=""><span>//将分数作为数值，由高到低排序  </span></li>
<li class="alt"><span>$grade["name"],SORT_STRING,SORT_ASC);  </span></li>
<li class=""><span>//将名字作为字符串，由小到大排序  </span></li>
<li class="alt">
<span></span><span class="tag"><strong><font color="#006699">?></font></strong></span><span> </span>
</li>
<li class=""><span>//输出结果  </span></li>
<li class="alt"><span> </span></li>
<li class=""><span>array(  </span></li>
<li class="alt">
<span>'score'=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span> </span>
</li>
<li class=""><span>array(  </span></li>
<li class="alt">
<span></span><span class="attribute"><font color="#ff0000">0</font></span><span>=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>95,  </span>
</li>
<li class="">
<span></span><span class="attribute"><font color="#ff0000">1</font></span><span>=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>'70',  </span>
</li>
<li class="alt">
<span></span><span class="attribute"><font color="#ff0000">2</font></span><span>=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>70,  </span>
</li>
<li class="">
<span></span><span class="attribute"><font color="#ff0000">3</font></span><span>=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>70,  </span>
</li>
<li class="alt">
<span></span><span class="attribute"><font color="#ff0000">4</font></span><span>=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>60,  </span>
</li>
<li class=""><span>),  </span></li>
<li class="alt">
<span>'name'=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span> </span>
</li>
<li class=""><span>array(  </span></li>
<li class="alt">
<span></span><span class="attribute"><font color="#ff0000">0</font></span><span>=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>'LiSi',  </span>
</li>
<li class="">
<span></span><span class="attribute"><font color="#ff0000">1</font></span><span>=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>'LiuQi',  </span>
</li>
<li class="alt">
<span></span><span class="attribute"><font color="#ff0000">2</font></span><span>=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>'WangWu',  </span>
</li>
<li class="">
<span></span><span class="attribute"><font color="#ff0000">3</font></span><span>=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>'ZhangSan',  </span>
</li>
<li class="alt">
<span></span><span class="attribute"><font color="#ff0000">4</font></span><span>=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>'ZhaoLiu',  </span>
</li>
<li class=""><span>),  </span></li>
<li class="alt"><span>)  </span></li>
</ol>
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2.array_rand() and shuffle(), one is to randomly take out one or more values ​​​​from the array, the other is to disrupt the order of the values ​​​​in the array, and then you can Retrieve values, they all implement the function of randomly extracting data from the array, and can be used to implement functions such as lottery.

3.array_reduce() iteratively applies the callback function function to each unit in the input array, thereby reducing the array to a single value. If the optional initial parameter is specified, it will be treated as the first value in the array, or as the final return value if the array is empty. 

<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 class=""><SPAN>functionrsum($v,$w){  </SPAN><LI class=alt><SPAN>$v+=$w;  </SPAN><LI class=""><SPAN>return$v;  </SPAN><LI class=alt><SPAN>}  </SPAN><LI class=""><SPAN> </SPAN><LI class=alt><SPAN>functionrmul($v,$w){  </SPAN><LI class=""><SPAN>$v*=$w;  </SPAN><LI class=alt><SPAN>return$v;  </SPAN><LI class=""><SPAN>}  </SPAN><LI class=alt><SPAN> </SPAN><LI class=""><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>a</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>array</FONT></SPAN><SPAN>(1,2,3,4,5);  </SPAN></SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>x</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>array</FONT></SPAN><SPAN>();  </SPAN></SPAN><LI class=""><SPAN>//实现array_sum()功能  </SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>b</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>array_reduce</FONT></SPAN><SPAN>($a,"rsum");//</SPAN><SPAN class=attribute-value><FONT color=#0000ff>1</FONT></SPAN><SPAN class=attribute><FONT color=#ff0000>15</FONT></SPAN><SPAN>=1+2+3+4+5  </SPAN></SPAN><LI class=""><SPAN> </SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>c</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>array_reduce</FONT></SPAN><SPAN>($a,"rmul",10);//</SPAN><SPAN class=attribute-value><FONT color=#0000ff>1</FONT></SPAN><SPAN class=attribute><FONT color=#ff0000>1200</FONT></SPAN><SPAN>=1*2*3*4*5*10  </SPAN></SPAN><LI class=""><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>d</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>array_reduce</FONT></SPAN><SPAN>($x,"rsum",1);//1  </SPAN></SPAN><LI class=alt><SPAN></SPAN><SPAN class=tag><STRONG><FONT color=#006699>?></span></font></strong></span><span> </span>
</li></ol>
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This function can realize the sum of an array (product, difference, etc. functions)


www.bkjia.comtruehttp: //www.bkjia.com/PHPjc/446540.htmlTechArticlePHP array functions are quite commonly used, so I studied PHP array functions and shared them with you here. Here's a look, hope it's useful to everyone. Today we learn PHP array functions,...
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