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Home Backend Development PHP Tutorial 今天看的视频里面有个例子不懂

今天看的视频里面有个例子不懂

Jun 23, 2016 pm 01:20 PM

是这样的  1. 下面的那个for循环的条件语句的$i在后面根本就没出现啊  那么这个条件有什么用呢
2.还有等号前面还有一个小点 不知道是干嘛用的  视频说是让它自身相加   这个里面让它自身相加有什么意义呢
就这两个问题 谢谢
for($i=0;$i{
   $nmsg.=dechex(mt_rand(0,15));
}


回复讨论(解决方案)

for($i=0;$i<4;$i++){   $nmsg.=dechex(mt_rand(0,15));}
Copy after login
Copy after login

上面的代码意思是:从0到15之间随机产生一个10进制的数,然后转化为16进制。总共循环产生4次($i的作用:控制循环次数),每一个16进制的数都用“点”连接(点的作用是连接字符串)。最后$nmsg的结果是由4个16进制数组成的字符串。

for($i=0;$i<4;$i++){   $nmsg.=dechex(mt_rand(0,15));}
Copy after login
Copy after login

上面的代码意思是:从0到15之间随机产生一个10进制的数,然后转化为16进制。总共循环产生4次($i的作用:控制循环次数),每一个16进制的数都用“点”连接(点的作用是连接字符串)。最后$nmsg的结果是由4个16进制数组成的字符串。



谢谢
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