Question

目前我有以下正则表达式匹配8位数的字母数字，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。我怎么能这样做？

preg_match('/[A-Za-z0-9]{8}/', $bio)

Answer 1

怎么样：

/^(?=2.*\d)[a-zA-Z0-9]{8}$/

如果数字2计入所需的2个数字之一。

/^(?=2.*\d.*\d)[a-zA-Z0-9]{8}$/

如果数字2不计入2个所需数字之一。

<强>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
----------------------------------------------------------------------

Answer 2

以2开头很容易，只需在开头添加它：

preg_match('/2[A-Za-z0-9]{7}/', $bio)

然而，正则表达式不适合第二个要求 - 确保至少有2位数。您可以设计一个检查内部两位数的正则表达式，但是无法检查长度为8.因此您要么制作两个单独的正则表达式（一个用于长度，一个用于2个数字）或分析输入逐个字符地编码。

正则表达式匹配从数字2开始的8个字母数字，并且至少有两个数字

2 个答案: