Easily master PHP logical operator syntax and usage techniques_PHP Tutorial

There is a lot worth learning in PHP. Here we mainly introduce PHP logical operators, including bitwise operators, comparison operators, etc. Bitwise operators allow setting specified bits in an integer. If the left and right parameters are both strings, the bitwise operators will operate on the characters in this string.

1. Bitwise operators of PHP logical operators :

<ol class="dp-xml">
<li class="alt"><span><span>&：$a & $b And（按位与） 将在 $a 和 $b 中都为 1 的位设为 1。  </span></span></li>
<li class=""><span>|：$a | $b Or（按位或） 将在 $a 或者 $b 中为 1 的位设为 1。  </span></li>
<li class="alt"><span>^：$a ^ $b Xor（按位异或） 将在 $a 和 $b 中不同的位设为 1。  </span></li>
<li class=""><span>~：~ $a Not（按位非） 将 $a 中为 0 的位设为 1，反之亦然。  </span></li>
<li class="alt">
<span></span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag><</SPAN></FONT></STRONG><SPAN>：$a </SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag><</SPAN></FONT></STRONG><SPAN> $b Shift left（左移） 将 $a 中的位向左移动 $b 次（每一次移动都表示“乘以 2”）。  </SPAN></SPAN><LI class=""><SPAN>$a </SPAN><STRONG><FONT color=#006699><SPAN class=tag>></span><span class="tag">></span></font></strong><span> $b Shift right（右移） 将 $a 中的位向右移动 $b 次（每一次移动都表示“除以 2”）。 </span>
</li>
</ol>

Bitwise operation symbols involve microscopic bit changes. For example, 5&3 then the storage of 5 The binary code is 0110 and the stored binary code of 3 is 0100. Then the logical AND budget of 5 and 3 is

<ol class="dp-xml">
<li class="alt"><span><span>0101  </span></span></li>
<li class=""><span>0011  </span></li>
<li class="alt"><span>0001 （结果为1） </span></li>
</ol>

. Then the result is still 1. The example is as follows:

<ol class="dp-xml">
<li class="alt"><span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag-name>html</SPAN><SPAN class=tag>></span></font></strong><span> </span></span></li>
<li class="">
<span></span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag-name>head</SPAN><SPAN class=tag>></span></font></strong><span> </span>
</li>
<li class="alt">
<span></span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag-name>title</SPAN><SPAN class=tag>></span></font></strong><span>php常量定义--阿涛随笔</span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>title</SPAN><SPAN class=tag>></span></font></strong><span> </span>
</li>
<li class="">
<span></span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>head</SPAN><SPAN class=tag>></span></font></strong><span> </span>
</li>
<li class="alt">
<span></span><strong><font color="#006699"><span class="tag"><</SPAN><SPAN class=tag-name>body</SPAN><SPAN class=tag>></span></font></strong><span> </span>
</li>
<li class="">
<span></span><strong><font color="#006699"><span class="tag"><?</SPAN><SPAN class=tag-name>php</SPAN></FONT></STRONG><SPAN> </SPAN></SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>a</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>5</FONT></SPAN><SPAN>;  </SPAN></SPAN><LI class=""><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>b</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>3</FONT></SPAN><SPAN>;  </SPAN></SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>c</FONT></SPAN><SPAN>=$a&$b;  </SPAN></SPAN><LI class=""><SPAN>echo $c."</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>echo 5&3;  </span></li>
<li class="">
<span></span><span class="tag"><strong><font color="#006699">?></font></strong></span><span> </span>
</li>
<li class="alt">
<span></span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>body</SPAN><SPAN class=tag>></span></font></strong><span> </span>
</li>
<li class="">
<span></span><strong><font color="#006699"><span class="tag"></</SPAN><SPAN class=tag-name>html</SPAN><SPAN class=tag>></span></font></strong><span> </span>
</li>
</ol>

is required for operation. Binary knowledge generally does not use bit operations.

2. PHP Logical Operators Comparison Operators :

Comparison operators, as their names suggest, allow you to compare two values ​​

<ol class="dp-xml">
<li class="alt"><span><span>==：等于 返回值 true or </span><span class="attribute">falsh</span><span> </span></span></li>
<li class=""><span>===：全等 返回值 true or falsh (PHP 4 only)  </span></li>
<li class="alt"><span>!=：不等 返回值 true or falsh  </span></li>
<li class="">
<span></span><span class="tag"><</SPAN><SPAN class=tag>></span><span>：不等 返回值 true or falsh 。  </span>
</li>
<li class="alt"><span>!==：非全等 返回值 true or falsh 。PHP 4 only)。  </span></li>
<li class="">
<span></span><span class="tag"><</SPAN><SPAN>：小与 非全等 返回值 true or falsh。  </SPAN></SPAN><LI class=alt><SPAN></SPAN><SPAN class=tag>></span><span>：大于 非全等 返回值 true or falsh。  </span>
</li>
<li class="">
<span></span><span class="tag"><</SPAN><SPAN>=：非全等 返回值 true or falsh 。  </SPAN></SPAN><LI class=alt><SPAN></SPAN><SPAN class=tag>></span><span>= ：非全等 返回值 true or falsh 。 </span>
</li>
</ol>

After comparison, a Boolean value is returned == and ===. The difference is that the former only compares values ​​and does not compare types. For example, 1 and '1' are They are considered to be the same, and === compares both values ​​and types. Error Control Operator (@) PHP supports one error control operator: @. When placed before a PHP expression, any error message that expression may produce is ignored. If the track_errors feature is enabled, any error messages generated by the expression are stored in the variable $php_errormsg. This variable is overwritten on every error, so check it as early as possible if you want to use it. The above is a brief introduction to PHP logical operators, I hope it will be helpful to everyone.

http://www.bkjia.com/PHPjc/446485.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/446485.htmlTechArticleThere is a lot worth learning about PHP. Here we mainly introduce PHP logical operators, including bitwise operators and comparisons. operators, etc. Bitwise operators allow carrying of specified bits in an integer...