Javascript 密码正则表达式：“至少 1 个字母、1 个数字、1 个特殊字符，并且不应以特殊字符开头”
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Regex for Password: "Atleast 1 letter, 1 number, 1 special character and SHOULD NOT start with a special character"
提问by adiga
I need a regular expression for a password field.
我需要一个密码字段的正则表达式。
The requirement is:
要求是：
The password Must be 8 to 20 characters in length
Must contain at least one letterand one numberand a special character from
!@#$%^&*()_+.Should not start with a special character
密码长度必须为 8 到 20 个字符
必须至少包含一个字母和一个数字以及一个来自
!@#$%^&*()_+.不应以特殊字符开头
I have tried
我试过了
^(?=.*[a-zA-Z])(?=.*\d)(?=.*[!@#$%^&*()_+])[A-Za-z\d!@#$%^&*()_+]{8,20}
It works but how do you restrict special characters from beginning the password? Also if you have a more efficient regex than the one mentioned above please suggest.
它有效，但是如何限制特殊字符从密码开始？此外，如果您有比上述更有效的正则表达式，请提出建议。
Thank you
谢谢
回答by nu11p01n73R
Its simple, just add one more character class at the begining
很简单，在开头多加一个字符类
^(?=.*[a-zA-Z])(?=.*\d)(?=.*[!@#$%^&*()_+])[A-Za-z\d][A-Za-z\d!@#$%^&*()_+]{7,19}$
[A-Za-z\d]Ensures that the first character is an alphabet or digit.[A-Za-z\d!@#$%^&*()_+]{7,19}will match minimum 7 maximum 19 character. This is required as he presceding character class would consume a single character making the total number of characters in the string as minimum 8 and maximum 20.$Anchors the regex at the end of the string. Ensures that there is nothing following our valid password
[A-Za-z\d]确保第一个字符是字母或数字。[A-Za-z\d!@#$%^&*()_+]{7,19}将匹配最少 7 个最多 19 个字符。这是必需的，因为他前面的字符类将消耗单个字符，使字符串中的字符总数最少为 8，最多为 20。$将正则表达式锚定在字符串的末尾。确保我们的有效密码后面没有任何内容
var pattern = new RegExp(/^(?=.*[a-zA-Z])(?=.*\d)(?=.*[!@#$%^&*()_+])[A-Za-z\d][A-Za-z\d!@#$%^&*()_+]{7,19}$/);
console.log(pattern.test("!@#123asdf!@#"));
console.log(pattern.test("123asdf!@#"));
console.log(pattern.test("12as#"));