Mining the PHP array function library array array creation and use

Mining the PHP array function library array array creation and use_PHP tutorial

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Release： 2016-07-15 13:27:07

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The function library in the array is the key point for us to learn arrays. Here we mainly introduce the PHP array function library array to create arrays. Let's share it with you. Fortunately, PHP is not difficult, and there are not many of these things. After learning a few lessons, we can start to use it to implement website functions one by one. By then, I believe you will become more and more energetic. Okay, let’s start today’s lesson. Today we are learning about arrays. Arrays are a data type that are used very frequently. Learning to handle arrays will make you more comfortable when building 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.

The PHP array function library creates a new array and uses array

<ol class="dp-xml"><li class="alt"><span><span>array array ( [mixed ...] ) </span></span></li></ol>

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to return an array created based on the parameters. Parameters can be indexed using the => operator. For information on what an array is please read the Arrays section. Note: array() is a language construct used to represent arrays literally, not a regular function. The syntax "index => values", separated by commas, defines the index and the value. The index can be a string or a number. If the index is omitted, an integer index starting from 0 is automatically generated. If the index is an integer, the next resulting index will be the largest integer index so far + 1. Note that if two identical indexes are defined, the latter one will overwrite the previous one. Although uncommon, adding a comma after the last defined array item is legal syntax.

The following example demonstrates how to create a two-dimensional array, how to assign keys to the corresponding array, and how to skip and continue numeric indexes in ordinary arrays.

PHP array function library example 1. array() example

<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>$</SPAN><SPAN class=attribute><FONT color=#ff0000>fruits</FONT></SPAN><SPAN> = </SPAN><SPAN class=attribute-value><FONT color=#0000ff>array</FONT></SPAN><SPAN> (  </SPAN></SPAN><LI class=alt><SPAN>"fruits"  =</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></span></font></strong></span><span> array("a" =</span><span class="tag"><strong><font color="#006699">></font></strong></span><span> "orange", "b" =</span><span class="tag"><strong><font color="#006699">></font></strong></span><span> "banana", "c" =</span><span class="tag"><strong><font color="#006699">></font></strong></span><span> "apple"),  </span>
</li>
<li class="">
<span>"numbers" =</span><span class="tag"><strong><font color="#006699">></font></strong></span><span> array(1, 2, 3, 4, 5, 6),  </span>
</li>
<li class="alt">
<span>"holes"   =</span><span class="tag"><strong><font color="#006699">></font></strong></span><span> array("first", </span><span class="attribute"><font color="#ff0000">5</font></span><span> =</span><span class="tag"><strong><font color="#006699">></font></strong></span><span> "second", "third")  </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>

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PHP array function library example 2. Automatic indexing of array()

<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>$</SPAN><SPAN class=attribute><FONT color=#ff0000>array</FONT></SPAN><SPAN class=attribute-value><FONT color=#0000ff>array</FONT></SPAN><SPAN> = array(1, 1, 1, 1,  1, </SPAN><SPAN class=attribute><FONT color=#ff0000>8</FONT></SPAN><SPAN> =</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></span></font></strong></span><span> 1,  </span><span class="attribute"><font color="#ff0000">4</font></span><span> =</span><span class="tag"><strong><font color="#006699">></font></strong></span><span> 1, 19, </span><span class="attribute"><font color="#ff0000">3</font></span><span> =</span><span class="tag"><strong><font color="#006699">></font></strong></span><span> 13);  </span>
</li>
<li class="alt"><span>print_r($array);  </span></li>
<li class="">
<span></span><span class="tag"><strong><font color="#006699">?></font></strong></span><span> </span>
</li>
</ol>

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The above example will output:

<ol class="dp-xml">
<li class="alt"><span><span>Array  </span></span></li>
<li class=""><span>(  </span></li>
<li class="alt">
<span>[0] =</span><span class="tag">></span><span> 1  </span>
</li>
<li class="">
<span>[1] =</span><span class="tag">></span><span> 1  </span>
</li>
<li class="alt">
<span>[2] =</span><span class="tag">></span><span> 1  </span>
</li>
<li class="">
<span>[3] =</span><span class="tag">></span><span> 13  </span>
</li>
<li class="alt">
<span>[4] =</span><span class="tag">></span><span> 1  </span>
</li>
<li class="">
<span>[8] =</span><span class="tag">></span><span> 1  </span>
</li>
<li class="alt">
<span>[9] =</span><span class="tag">></span><span> 19  </span>
</li>
<li class=""><span>) </span></li>
</ol>

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Note that index 3 is defined twice, retaining the last value of 13. Index 4 is defined after index 8, and the next automatically generated index (the one with value 19) is 9 because the largest index is 8.