PHP函数array_merge()与加号运算符的不同之处

PHP函数array_merge()与加号运算符的不同之处_PHP教程

php中文网

发布： 2016-07-15 13:29:05

原创

1056人浏览过

我们今天为大家介绍的是array_merge在参考手册中的说明如下：

PHP函数array_merge()将两个或多个数组的单元合并起来，一个数组中的值附加在前一个数组的后面。返回作为结果的数组。

如果输入的数组中有相同的字符串键名，则该键名后面的值将覆盖前一个值。然而，如果数组包含数字键名，后面的值将不会覆盖原来的值，而是附加到后面。

PHP函数array_merge()与加号运算符两个的区别是：

1.数组键名为数字键名时，要合并的两个数组中有同名数字KEY的时候，使用array_merge()不会覆盖掉原来的值，而使用“＋”合并数组则会把最先出现的值作为最终结果返回，而把后面的数组拥有相同键名的那些值“抛弃”掉（注意：不是覆盖而是保留最先出现的那个值）。例子：

立即学习“PHP免费学习笔记（深入）”；

<OL class=dp-xml><LI class=alt><SPAN><SPAN>$</SPAN><SPAN class=attribute-value><FONT color=#0000ff>array</FONT></SPAN><SPAN class=attribute><FONT color=#ff0000>array1</FONT></SPAN><SPAN> = array(</SPAN><SPAN class=attribute><FONT color=#ff0000>1</FONT></SPAN><SPAN>=</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN>'0');  </SPAN></SPAN><LI class=""><SPAN>$</SPAN><SPAN class=attribute-value><FONT color=#0000ff>array</FONT></SPAN><SPAN class=attribute><FONT color=#ff0000>array2</FONT></SPAN><SPAN> = array(</SPAN><SPAN class=attribute><FONT color=#ff0000>1</FONT></SPAN><SPAN>=</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> "data");  </SPAN></SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>result1</FONT></SPAN><SPAN> = $array2 + $array1;/*结果为$array2的值*/  </SPAN></SPAN><LI class=""><SPAN>print_r($result);  </SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>result</FONT></SPAN><SPAN> = $array1 + $array2 ;/*结果为$array1的值*/  </SPAN></SPAN><LI class=""><SPAN>print_r($result);  </SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>result3</FONT></SPAN><SPAN> = </SPAN><SPAN class=attribute-value><FONT color=#0000ff>array_merge</FONT></SPAN><SPAN>($array2,$array1);/*结果为$array2和$array1的值，键名被重新分配*/  </SPAN></SPAN><LI class=""><SPAN>print_r($result3);  </SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>result4</FONT></SPAN><SPAN> = </SPAN><SPAN class=attribute-value><FONT color=#0000ff>array_merge</FONT></SPAN><SPAN>($array1,$array2);/*结果为$array1和$array2的值，键名被重新分配*/  </SPAN></SPAN><LI class=""><SPAN>print_r($result4);  </SPAN></LI></OL>

登录后复制

输出结果为：

<OL class=dp-xml><LI class=alt><SPAN><SPAN>Array ( [1] =</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> data )  </SPAN></SPAN><LI class=""><SPAN>Array ( [1] =</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> 0 )  </SPAN></SPAN><LI class=alt><SPAN>Array (  </SPAN><LI class=""><SPAN>[0] =</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> data  </SPAN></SPAN><LI class=alt><SPAN>[1] =</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> 0  </SPAN></SPAN><LI class=""><SPAN>)  </SPAN><LI class=alt><SPAN>Array  </SPAN><LI class=""><SPAN>(  </SPAN><LI class=alt><SPAN>[0] =</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> 0  </SPAN></SPAN><LI class=""><SPAN>[1] =</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> data  </SPAN></SPAN><LI class=alt><SPAN>)  </SPAN></LI></OL>

登录后复制

2.当相同数组键名为字符时，“＋”运算符与键名为数字时一样，但PHP函数array_merge()此时会覆盖掉前面相同键名的值。

例子：

算家云

高效、便捷的人工智能算力服务平台

查看详情

<OL class=dp-xml><LI class=alt><SPAN><SPAN>$</SPAN><SPAN class=attribute-value><FONT color=#0000ff>array</FONT></SPAN><SPAN class=attribute><FONT color=#ff0000>array1</FONT></SPAN><SPAN> = array('asd'=</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN>'0');  </SPAN></SPAN><LI class=""><SPAN>$</SPAN><SPAN class=attribute-value><FONT color=#0000ff>array</FONT></SPAN><SPAN class=attribute><FONT color=#ff0000>array2</FONT></SPAN><SPAN> = array('asd' =</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> "data");  </SPAN></SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>result1</FONT></SPAN><SPAN> = $array2 + $array1;/*结果为$array2的值*/  </SPAN></SPAN><LI class=""><SPAN>print_r($result);  </SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>result</FONT></SPAN><SPAN> = $array1 + $array2 ;/*结果为$array1的值*/  </SPAN></SPAN><LI class=""><SPAN>print_r($result);  </SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>result3</FONT></SPAN><SPAN> = </SPAN><SPAN class=attribute-value><FONT color=#0000ff>array_merge</FONT></SPAN><SPAN>($array2,$array1);/*结果为$array1*/  </SPAN></SPAN><LI class=""><SPAN>print_r($result3);  </SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>result4</FONT></SPAN><SPAN> = </SPAN><SPAN class=attribute-value><FONT color=#0000ff>array_merge</FONT></SPAN><SPAN>($array1,$array2);/*结果为$array2*/  </SPAN></SPAN><LI class=""><SPAN>print_r($result4);  </SPAN></LI></OL>

登录后复制

输出结果为：

<OL class=dp-xml><LI class=alt><SPAN><SPAN>Array ( [asd] =</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> data )  </SPAN></SPAN><LI class=""><SPAN>Array ( [asd] =</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> 0 )  </SPAN></SPAN><LI class=alt><SPAN>Array ( [asd] =</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> 0 )  </SPAN></SPAN><LI class=""><SPAN>Array ( [asd] =</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> data )  </SPAN></SPAN></LI></OL>

登录后复制

以上就是PHP函数array_merge()与加号运算符在实际使用中的不同之处。