Play with PHP numerical functions_PHP tutorial-PHP Tutorial-php.cn

Play with PHP numerical functions_PHP tutorial

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Release： 2016-07-15 13:27:27

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There is a lot worth learning in PHP. Here we mainly introduce PHP array functions. Let’s briefly summarize PHP first. For ordinary computer enthusiasts, PHP may be an unfamiliar name. Friends who pay more attention to the Internet, especially those who pay attention to website construction technology, may have heard of PHP. PHP is a simple yet powerful programming language designed for dynamically creating HTML content.

PHP itself is a simple yet powerful language. The PHP language has core features such as powerful string and array processing capabilities, and has greatly improved support for object-oriented programming (PHP5 and above). By using standard and optional extension modules, PHP applications can connect to more than a dozen databases such as MySQL or Oracle, draw, create PDF files, and create and parse XML files. You can also use C language to write your own PHP extension module. For example, provide a PHP interface function in an existing code base. You can also run PHP under Windows, use COM to control other Windows applications such as Word and Excel, or use ODBC to connect to a database. The above is a brief introduction to PHP. Let’s take a look at the relevant knowledge of PHP array functions.

1. Return the function key() of the key of the current array value, and return false at the end

<ol class="dp-xml">
<li class="alt"><span><span>$</span><span class="attribute"><font color="#ff0000">a</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">array</font></span><span>("tom"=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>"21","jim"=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>"22","andy"=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>"25");  </span></span></li>
<li class=""><span>//配置key函数循环读取$a的键并赋值$key，直到读取完毕  </span></li>
<li class="alt">
<span>while($</span><span class="attribute"><font color="#ff0000">key</font></span><span class="attribute-value"><font color="#0000ff">key</font></span><span>=key($a)){  </span>
</li>
<li class=""><span>echo $key;  </span></li>
<li class="alt"><span>//next负责将数组指针移向下一个  </span></li>
<li class=""><span>next($a);  </span></li>
<li class="alt"><span>} </span></li>
</ol>

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2. Get the PHP value of the current pointer Function current returns false at the end

<ol class="dp-xml">
<li class="alt"><span><span>$</span><span class="attribute"><font color="#ff0000">a</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">array</font></span><span>("tom"=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>"21","jim"=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>"22","andy"=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>"25");  </span></span></li>
<li class=""><span>//配置key函数循环读取$a的数组值并赋值$key，直到读取完毕  </span></li>
<li class="alt">
<span>while($</span><span class="attribute"><font color="#ff0000">key</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">current</font></span><span>($a)){  </span>
</li>
<li class=""><span>echo $key;  </span></li>
<li class="alt"><span>next($a);  </span></li>
<li class=""><span>} </span></li>
</ol>

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3. The combined version of each() of the above two examples returns an array, Can be read with the help of list.

and next can be omitted because it automatically jumps to

<ol class="dp-xml">
<li class="alt"><span><span>$</span><span class="attribute"><font color="#ff0000">a</font></span><span>=</span><span class="attribute-value"><font color="#0000ff">array</font></span><span>("tom"=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>"21","jim"=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>"22","andy"=</span><span class="tag"><strong><font color="#006699">></font></strong></span><span>"25");  </span></span></li>
<li class=""><span>//配置循环读取$a的数组值与键并分别赋值，直到读取完毕  </span></li>
<li class="alt"><span>while(list($key, $val)=each($a)){  </span></li>
<li class="">
<span>echo $key,$val,"</span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag-name>br</SPAN><SPAN class=tag>></span></font></strong><span>";  </span>
</li>
<li class="alt"><span>} </span></li>
</ol>

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4. Remember in particular, the function that moves the pointer

(1)next statement, as the name suggests, means moving to the next one

<ol class="dp-xml">
<li class="alt"><span><span>$</span><span class="attribute">a</span><span>=</span><span class="attribute-value">array</span><span>("tom","jim","andy");  </span></span></li>
<li class=""><span>echo next($a);//输出jim  </span></li>
<li class="alt"><span>echo next($a);//输出andy </span></li>
</ol>

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(2)prev statement, a statement that moves the pointer forward. I will not give an example for the

(3) reset statement as above, and return to the first position. I will not give an example for the

(4) end statement as above, but I will not give an example for the last one! !