6位正则表达式 [英] 6 digits regular expression

问题描述

我需要一个至少需要一位数字和最多六位数字的正则表达式.

I need a regular expression that requires at least ONE digits and SIX maximum.

我已经解决了这个问题，但它们似乎都不起作用.

I've worked out this, but neither of them seems to work.

^[0-9][0-9]\?[0-9]\?[0-9]\?[0-9]\?[0-9]\?$

^[0-999999]$

还有什么建议吗?

推荐答案

您可以使用范围量词 {min,max} 指定最小 1 位和最大 6 位为:

You can use range quantifier {min,max} to specify minimum of 1 digit and maximum of 6 digits as:

^[0-9]{1,6}$

说明:

^     : Start anchor
[0-9] : Character class to match one of the 10 digits
{1,6} : Range quantifier. Minimum 1 repetition and maximum 6.
$     : End anchor

为什么你的正则表达式不起作用?

您几乎接近正则表达式:

You were almost close on the regex:

^[0-9][0-9]\?[0-9]\?[0-9]\?[0-9]\?[0-9]\?$

由于您通过在 \ 前面对 ? 进行转义，? 不再充当正则表达式元字符 (0 或 1 重复)，但按字面处理.

Since you had escaped the ? by preceding it with the \, the ? was no more acting as a regex meta-character ( for 0 or 1 repetitions) but was being treated literally.

要修复它，只需删除 \ 即可.

To fix it just remove the \ and you are there.

在 rubular 上查看.

基于量词的正则表达式更短、更易读并且可以轻松扩展到任意数量的数字.

The quantifier based regex is shorter, more readable and can easily be extended to any number of digits.

你的第二个正则表达式:

Your second regex:

^[0-999999]$

相当于:

^[0-9]$

只匹配一位数字的字符串.它们是等价的，因为字符类 [aaaab] 与 [ab] 相同.

which matches strings with exactly one digit. They are equivalent because a character class [aaaab] is same as [ab].

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