目前我有以下与 8 位字母数字匹配的正则表达式,我想修改它,使其必须以数字 2 开头,并且在这 8 位数字中至少包含 2 个数字。我该怎么做?
preg_match('/[A-Za-z0-9]{8}/', $bio)
怎么样:
/^(?=2.*'d)[a-zA-Z0-9]{8}$/
如果数字2
计入 2 个所需数字之一。
/^(?=2.*'d.*'d)[a-zA-Z0-9]{8}$/
如果数字2
不计入 2 个所需数字之一。
解释:
The regular expression:
(?-imsx:^(?=2.*'d)[a-zA-Z0-9]{8}$)
matches as follows:
NODE EXPLANATION
----------------------------------------------------------------------
(?-imsx: group, but do not capture (case-sensitive)
(with ^ and $ matching normally) (with . not
matching 'n) (matching whitespace and #
normally):
----------------------------------------------------------------------
^ the beginning of the string
----------------------------------------------------------------------
(?= look ahead to see if there is:
----------------------------------------------------------------------
2 '2'
----------------------------------------------------------------------
.* any character except 'n (0 or more times
(matching the most amount possible))
----------------------------------------------------------------------
'd digits (0-9)
----------------------------------------------------------------------
) end of look-ahead
----------------------------------------------------------------------
[a-zA-Z0-9]{8} any character of: 'a' to 'z', 'A' to 'Z',
'0' to '9' (8 times)
----------------------------------------------------------------------
$ before an optional 'n, and the end of the
string
----------------------------------------------------------------------
) end of grouping
----------------------------------------------------------------------
很容易让它以 2 开头,只需在开头添加它:
preg_match('/2[A-Za-z0-9]{7}/', $bio)
但是,正则表达式不适合第二个要求 - 确保至少有 2 位数字。您可以设计一个正则表达式来检查内部的两位数,但无法检查长度是否为 8。因此,您可以制作两个单独的正则表达式(一个用于长度,一个用于 2 位数字),或者逐个字符分别分析代码中的输入。