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Home Backend Development PHP Tutorial UTF-8编码时如何把中文和各种特殊标点符号当作长度为2

UTF-8编码时如何把中文和各种特殊标点符号当作长度为2

Jun 06, 2016 pm 08:49 PM
php utf-8 form validation

这标题有点二。。。不知道怎么描述,将就着看吧。

注册用户时 经常见到的长度限制是:
中文的话可以输入12个,英文的话可以输入24个。
这在PHP要怎么验证呢?

UTF-8编码时
用strlen一个中文的长度是3。
用mb_strlen一个中文的长度是1。

回复内容:

这标题有点二。。。不知道怎么描述,将就着看吧。

注册用户时 经常见到的长度限制是:
中文的话可以输入12个,英文的话可以输入24个。
这在PHP要怎么验证呢?

UTF-8编码时
用strlen一个中文的长度是3。
用mb_strlen一个中文的长度是1。

看来你们都不知道 有个函数名叫 mb_strwidth

UTF-8 编码的字符可能由 1~3个 字节组成,具体数目可以由第一个字节判断出来。(理论上可能更长,但这里假设不超过3个字节)

UTF-8的编码方式

  1. 第一个字节大于224的,它与它之后的2个字节一起组成一个UTF-8字符
  2. 第一个字节大于192小于224的,它与它之后的1个字节组成一个UTF-8字符
  3. 否则第一个字节本身就是一个英文字符(包括数字和一小部分标点符号)。

获取长度可以指定编码:

mb_strlen($str,'gb2312')
Copy after login

很简单,转换成cp936编码,然后再直接strlen就行了。

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