PHP中"or"、"||"与赋值运算符的优先级
2013-09-29 16:30
190 查看
初学PHP,起初以为||与or是相同的,在PHP的manual中看到||与or优先级差别。
url:http://www.php.net/manual/zh/language.types.boolean.php
View Code
输出结果:
![](data:image/png;base64,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)
可以看出:
OR的优先级低于=
|| 的优先级高于=
url:http://www.php.net/manual/zh/language.types.boolean.php
<?php $x = false; $y = true; $z = $x or $y; var_dump($z); $z = ($x or $y); var_dump($z); $z = $x || $y; var_dump($z); $z = ($x || $y); var_dump($z); ?>
View Code
输出结果:
可以看出:
OR的优先级低于=
|| 的优先级高于=
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