[英]Regex to match 1 or 2 alphabets followed by 1 or 2 digits
I need help forming a regular expression to check if the input string is ONLY of the pattern 1 or 2 alphabets (can be lower or uppercase) followed by 1 or 2 digits. 我需要形成正则表达式的帮助,以检查输入的字符串是否仅是模式1或2个字母(可以是小写或大写),然后是1或2个数字。 Valid strings would be d1,d15,ha1,ha20 so on.
有效字符串为d1,d15,ha1,ha20,依此类推。
The following should do what you want: 以下应该做您想要的:
\A[a-zA-Z]{1,2}\d{1,2}\z
[a-zA-Z]
is a character class that matches any letter, \\d
is equivalent to [0-9]
and matches any digit, and {1,2}
means "repeat the previous element 1 or 2 times". [a-zA-Z]
是与任何字母匹配的字符类, \\d
等效于[0-9]
并且与任何数字匹配,并且{1,2}
意思是“将前一个元素重复1或2次”。
\\A
and \\z
are anchors, and they only match at the beginning and end of a string respectively (they don't match any characters, they just require the string to start or end at them to allow a match). \\A
和\\z
是锚点,它们分别仅在字符串的开头和结尾匹配(它们不匹配任何字符,它们只需要在字符串的开头或结尾进行匹配即可)。
You will also commonly see the anchors ^
and $
, I used \\A
and \\z
because $
will match just before a newline at the end of the string and can have its behavior modified by options, whereas \\z
always means the very end of the string. 您通常还会看到锚点
^
和$
,我使用了\\A
和\\z
因为$
会在字符串末尾的换行符之前匹配,并且可以通过options修改其行为,而\\z
始终表示末尾字符串。
The following page gives a nice summary on regular expression syntax: 下一页对正则表达式语法进行了很好的总结:
http://www.regular-expressions.info/reference.html http://www.regular-expressions.info/reference.html
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