1、首先定义一个字符串:$str = 'apple';其次定义一个数组:$arr = array('apple', 'orange', 'strawberry')。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/b21c8701a18b87d673e42c1f080828381f30fd08?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
2、加入函数:in_array(),判断$arr中,是否存在$str。如果存在则在屏幕上打印出:$str的值;如果不存在,则在屏幕上打印:找不到。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/6c224f4a20a44623737122629722720e0cf3d773?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
3、将编写的PHP文件保存,并在浏览器运行,观察效果,成功返回了$str的值,表明$str存在于$arr数组中。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/8b13632762d0f703fddf12dc07fa513d2697c545?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
4、修改$str的值,参考代码如下:$str=pear。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/8ad4b31c8701a18bd47a954f912f07082838fe19?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
5、保存修改之后的PHP文件,再次在浏览器运行文件,此次,因为数组中不存在$str的值,所以屏幕上打印出:找不到。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/0df3d7ca7bcb0a4671f50f396463f6246a60afdf?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)