JavaScript中数组函数array()的相关介绍-js教程-PHP中文网

JavaScript中数组函数array()的相关介绍

巴扎黑

发布： 2017-08-17 14:49:06

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在程序语言中数组的重要性不言而喻，javascript中数组也是最常使用的对象之一，数组是值的有序集合，由于弱类型的原因，javascript中数组十分灵活、强大，不像是java等强类型高级语言数组只能存放同一类型或其子类型元素，javascript在同一个数组中可以存放多种类型的元素，而且是长度也是可以动态调整的，可以随着数据增加或减少自动对数组长度做更改。

Array()是一个用来构建数组的内建构造器函数。数组主要由如下三种创建方式：

<span class="pln">array </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">Array</span><span class="pun">()</span><br/><span class="pln">array </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">Array</span><span class="pun">([</span><span class="pln">size</span><span class="pun">])</span><span class="pln">array </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">new</span><span class="pln"> </span><span class="typ">Array</span><span class="pun">(</span><span class="pln">element0</span><span class="pun">,</span><span class="pln"> element1</span><span class="pun">,</span><span class="pln"> </span><span class="pun">...,</span><span class="pln"> elementN</span><span class="pun">)</span>

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参数

参数 size 是期望的数组元素个数。返回的数组，length 字段将被设为 size 的值。

参数 element ..., elementn 是参数列表。当使用这些参数来调用构造函数 Array() 时，新创建的数组的元素就会被初始化为这些值。它的 length 字段也会被设置为参数的个数。

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返回值

返回新创建并被初始化了的数组。

如果调用构造函数 Array() 时没有使用参数，那么返回的数组为空，length 字段为 0。

当调用构造函数时只传递给它一个数字参数，该构造函数将返回具有指定个数、元素为 undefined 的数组。

当其他参数调用 Array() 时，该构造函数将用参数指定的值初始化数组。

当把构造函数作为函数调用，不使用 new 运算符时，它的行为与使用 new 运算符调用它时的行为完全一样。

Array 对象方法

Array 对象属性

PHP的使用技巧集

PHP 独特的语法混合了 C、Java、Perl 以及 PHP 自创新的语法。它可以比 CGI或者Perl更快速的执行动态网页。用PHP做出的动态页面与其他的编程语言相比，PHP是将程序嵌入到HTML文档中去执行，执行效率比完全生成HTML标记的CGI要高许多。下面介绍了十个PHP高级应用技巧。 1, 使用 ip2long() 和 long2ip() 函数来把 IP 地址转化成整型存储到数据库里

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concat()方法：

合并数组

[1,2]concat([3,4],[5,6]);//[1,2,3,4,5,6]

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join()方法：

<span class="tag"><script</span><span class="pln"> </span><span class="atn">type</span><span class="pun">=</span><span class="atv">"text/javascript"</span><span class="tag">></span><br/><span class="pln"> </span><span class="kwd">var</span><span class="pln"> a </span><span class="pun">=</span><span class="pln"> </span><span class="pun">[</span><span class="lit">1</span><span class="pun">,</span><span class="lit">2</span><span class="pun">,</span><span class="lit">3</span><span class="pun">];</span><br/><span class="pln"> a</span><span class="pun">.</span><span class="pln">join</span><span class="pun">(</span><span class="str">""</span><span class="pun">);</span><span class="com">// =>"123"</span><span class="tag"></script></span>

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pop()方法：

移除数组最后一个元素，并将其返回

<span class="tag"><script</span><span class="pln"> </span><span class="atn">type</span><span class="pun">=</span><span class="atv">"text/javascript"</span><span class="tag">></span><br/><span class="pln"> </span><span class="kwd">var</span><span class="pln"> fruits </span><span class="pun">=</span><span class="pln"> </span><span class="pun">[</span><span class="str">"apple"</span><span class="pun">,</span><span class="str">"banana"</span><span class="pun">,</span><span class="str">"pineapple"</span><span class="pun">];</span><br/><span class="pln"> fruits</span><span class="pun">.</span><span class="pln">pop</span><span class="pun">();</span><span class="com">// pineapple </span><br/><span class="pln"> console</span><span class="pun">.</span><span class="pln">log</span><span class="pun">(</span><span class="pln">fruits</span><span class="pun">);</span><span class="com">//["apple","banana"]</span><span class="tag"></script></span>

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shift()方法：

删除并返回数组的第一个元素。

<span class="tag"><script</span><span class="pln"> </span><span class="atn">type</span><span class="pun">=</span><span class="atv">"text/javascript"</span><span class="tag">></span><br/><span class="pln"> </span><span class="kwd">var</span><span class="pln"> a </span><span class="pun">=</span><span class="pln"> </span><span class="pun">[</span><span class="lit">1</span><span class="pun">,</span><span class="lit">2</span><span class="pun">,</span><span class="lit">3</span><span class="pun">];</span><br/><span class="pln"> a</span><span class="pun">.</span><span class="pln">shift</span><span class="pun">();</span><span class="com">//1</span><br/><span class="pln"> console</span><span class="pun">.</span><span class="pln">log</span><span class="pun">(</span><span class="pln">a</span><span class="pun">);</span><span class="com">//[2,3]</span><span class="tag"></script></span>

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slice(start,end)

方法：截取数组的某一部分，不会对原数组进行任何修改。

<span class="tag"><script</span><span class="pln"> </span><span class="atn">type</span><span class="pun">=</span><span class="atv">"text/javascript"</span><span class="tag">></span><br/><span class="pln">  </span><span class="kwd">var</span><span class="pln"> num </span><span class="pun">=</span><span class="pln"> </span><span class="pun">[</span><span class="str">"a"</span><span class="pun">,</span><span class="str">"b"</span><span class="pun">,</span><span class="str">"c"</span><span class="pun">,</span><span class="str">"d"</span><span class="pun">,</span><span class="str">"e"</span><span class="pun">];</span><br/><span class="pln">  console</span><span class="pun">.</span><span class="pln">log</span><span class="pun">(</span><span class="pln">num</span><span class="pun">.</span><span class="pln">slice</span><span class="pun">(</span><span class="lit">1</span><span class="pun">,</span><span class="lit">4</span><span class="pun">));</span><span class="com">//["b","c","d"]</span><br/><span class="pln">  console</span><span class="pun">.</span><span class="pln">log</span><span class="pun">(</span><span class="pln">num</span><span class="pun">);</span><span class="com">//["a","b","c","d","e"]</span><span class="tag"></script></span>

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splice(start,delete_count,i1,i2…)

方法：删除数组元素的同时添加新的元素。i1,i2为要插入的新元素

<span class="tag"><script</span><span class="pln"> </span><span class="atn">type</span><span class="pun">=</span><span class="atv">"text/javascript"</span><span class="tag">></span><br/><span class="pln"> </span><span class="kwd">var</span><span class="pln"> arr </span><span class="pun">=</span><span class="pln"> </span><span class="pun">[</span><span class="str">"js"</span><span class="pun">,</span><span class="str">"css"</span><span class="pun">,</span><span class="str">"html"</span><span class="pun">,</span><span class="str">"php"</span><span class="pun">,</span><span class="str">"c"</span><span class="pun">];</span><br/><span class="pln"> arr</span><span class="pun">.</span><span class="pln">splice</span><span class="pun">(</span><span class="lit">1</span><span class="pun">,</span><span class="pln"> </span><span class="lit">2</span><span class="pun">,</span><span class="str">"python"</span><span class="pun">,</span><span class="str">"jquery"</span><span class="pun">);</span><span class="com">//["css","html"]</span><br/><span class="pln"> console</span><span class="pun">.</span><span class="pln">log</span><span class="pun">(</span><span class="pln">arr</span><span class="pun">);</span><span class="com">//["js","python","jquery""php","c"]</span><span class="tag"></script</span>

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