[英]C# - UK Postcode Regex Expression not working as expected?
I looked at many questions on this website such as this one for Regex Expression to validate UK Postcodes: 我看着这个网站上的许多问题,如这一次的正则表达式表达式验证英国的邮政编码:
I have the following examples: 我有以下示例:
FA4 5SC [Valid] FA4 5SC [有效]
FA45SC [Valid] FA45SC [有效]
1FA4 5SC [Invalid] 1FA4 5SC [无效]
I have the following code: 我有以下代码:
static void Main(string[] args)
{
string[] postcodes = { "FA4 5SC", "FA45SC",
"1FA4 5SC"};
Regex rgx = new Regex("^([Gg][Ii][Rr] 0[Aa]{2})|((([A-Za-z][0-9]{1,2})|(([A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2})|(([A-Za-z][0-9][A-Za-z])|([A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z])))) [0-9][A-Za-z]{2})$");
foreach (string postcode in postcodes)
Console.WriteLine("{0} {1} a valid postcode number.",
postcode,
rgx.IsMatch(postcode) ? "is" : "is not");
Console.ReadKey();
}
I get the following output: 我得到以下输出:
FA4 5SC is a valid postcode number.
FA45SC is not a valid postcode number.
1FA4 5SC is a valid postcode number.
What do I need to amend in my regex so it invalidates the last two postcodes. 我需要在正则表达式中进行哪些修改,以使后两个邮政编码无效。 Meaning if a postcode starts with a number it should be invalid.
这意味着如果邮政编码以数字开头,则应该无效。
如果您还希望此FA45SC
有效,请尝试以下操作:
Regex rgx = new Regex("^([Gg][Ii][Rr] 0[Aa]{2}|([A-Za-z][0-9]{1,2}|[A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2}|[A-Za-z][0-9][A-Za-z]|[A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z]) {0,1}[0-9][A-Za-z]{2})$");
I believe the regular expression has a precedence error - the alternation after the first parentheses group has lower precedence than the caret, so it only tests if it find that group at the beginning of the string. 我相信正则表达式有一个优先级错误-第一个括号组之后的交替优先级比插入符号低,因此它仅测试是否在字符串开头找到该组。 Also, it has a lot of unneeded parenthesis for the alternation options otherwise, which makes it pretty hard to follow.
另外,对于其他选项,它还有很多不需要的括号,这使得很难理解。
Try this: 尝试这个:
Regex rgx = new Regex("^([Gg][Ii][Rr] 0[Aa]{2}|([A-Za-z][0-9]{1,2}|[A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2}|[A-Za-z][0-9][A-Za-z]|[A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z]) [0-9][A-Za-z]{2})$");
To make the space optional, 为了使空间可选,
Regex rgx = new Regex("^([Gg][Ii][Rr] 0[Aa]{2}|([A-Za-z][0-9]{1,2}|[A-Za-z][A-Ha-hJ-Yj-y][0-9]{1,2}|[A-Za-z][0-9][A-Za-z]|[A-Za-z][A-Ha-hJ-Yj-y][0-9]?[A-Za-z]) ?[0-9][A-Za-z]{2})$");
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