[英]How to verify a string in Javascript using regular expression?
I am pretty noob at JavaScript RegExp. 我在JavaScript RegExp上很菜鸟。 I just need to verify whether a string is 4 characters long and contains only caps letters (AZ). 我只需要验证字符串是否为4个字符长并且仅包含大写字母(AZ)。 Any help, highly appreciated. 任何帮助,高度赞赏。
Quick and dirty way, you can easily do it using: 快速而肮脏的方式,您可以使用以下方法轻松完成此操作:
^[A-Z][A-Z][A-Z][A-Z]$
Snippet 片段
<input id="text" /> <input type="button" onclick="return check();" value="Check" /> <script> function check() { var value = document.getElementById("text").value; if (/^[AZ][AZ][AZ][AZ]$/.test(value)) alert("Passes"); else alert("Failed"); } </script>
Shorter Version 短版
^[A-Z]{4}$
This uses the quantifiers {4}
. 这使用了量词{4}
。
You could use a quantifier as well with a range from A
to Z
and start and end position of the line. 您也可以使用范围从A
到Z
以及行的开始和结束位置的量词。
/^[A-Z]{4}$/
Explanation 说明
/^[AZ]{4}$/
^
asserts position at start of the string ^
在字符串开头声明位置
Match a single character present in the list below 匹配以下列表中存在的单个字符
[AZ]{4}
{4}
Quantifier — Matches exactly 4 times {4}
量词 -精确匹配4次
AZ
a single character in the range between A (ASCII 65) and Z (ASCII 90) (case sensitive) AZ
是介于A(ASCII 65)和Z(ASCII 90)之间的单个字符(区分大小写)
$
asserts position at the end of the string, or before the line terminator right at the end of the string (if any) $
声明位置在字符串末尾,或者在行终止符之前在字符串末尾(如果有)
You could use this: 您可以使用此:
/^[AZ]{4}$/.test('your_string')
Example: 例:
var str = 'YEAH';
if(/^[A-Z]{4}$/.test(str)) {
//true
}
else {
//false
}
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