正则表达式仅用于字母数字而不是数字

^([0-9 A-Z]*[A-Z][0-9 A-Z]*[0-9][0-9 A-Z]*|[0-9 A-Z]*[0-9][0-9 A-Z]*[A-Z][0-9 A-Z]*)$

它匹配

> ^ – 字符串的开头
然后有两个选择.备选方案1：
> [0-9 A-Z] * – 0允许字符
> [A-Z] – 一个大写的ASCII字母(强制子模式)
> [0-9 A-Z] * – 0允许字符
> [0-9] – 一个数字
> [0-9 A-Z] * – 0允许字符
备选方案2与上面相同,但数字和大写字母字符类被交换以匹配1A或A1字符串.
> $ – 字符串结尾

因此,所需的最小字符串长度为2个字符.

见regex demo和IDEONE demo：

s <- c("3 T1F ROHITE01WMILWI16","3 T1F ROHITE01WMILwI16","3 T1F ROHITE01WMIL.I16","1234","aaaa","T1F ROHITH01WMILWI16")
grep("^[0-9 A-Z]*[A-Z][0-9 A-Z]*[0-9][0-9 A-Z]*$",s,value=TRUE)

如果您需要支持任何长度的字符串,请使用this PCRE regex：

^(?=[^A-Z]*[A-Z])(?=[^0-9]*[0-9])[0-9 A-Z]*$

(？= [^ A-Z] * [A-Z])预测需要至少一个大写字母,而(？= [^ 0-9] * [0-9])需要一个数字.

见IDEONE demo：

s <- c("3 T1F ROHITE01WMILWI16","T1F ROHITH01WMILWI16")
grep("^(?=[^A-Z]*[A-Z])(?=[^0-9]*[0-9])[0-9 A-Z]*$",perl=TRUE,value=TRUE)