正则表达式，匹配“\\”和“\\”之间长4或5位的字符串

Question

I need to build a regex. the string i want to match always starts with \\ then 4 or 5 numbers then another \\

For example.

1. Welcome Home<\\217.163.24.49\\7778\\False,
2. Euro Server\\217.163.26.20\\7778\\False,
3. Instagib!)\\85.236.100.115\\8278\\False,

in first example i need "7778". In second example i need "7778". In third example i need "8278".

these 4 digit numbers is actually a port number, and its the only time on each line that this series of characters (eg, \\7778\\ ) would appear. sometimes the port number is 4 digits long, sometimes its 5.

I already know how to keep the string for later use using Regex.Match.Success, its just the actual regex pattern I am looking for here.

thanks

Answer 1

var match=Regex.Match(@"\1234\",@"\\(?<num>\d{4,5})\\"); 


if(match.Success)
{
    var numString=match.Groups["num"].Value;
}

or (if you don't like using groups) you can use lookbehind and lookahead assertions to ensure your 4-5 digit match is surrounded by slashes:

var match=Regex.Match(@"\1234\",@"(?<=\\)\d{4,5}(?=\\)");
if(match.Success)
{
    var numString=match.Value;
}

Answer 2

@"\\(\d{4,5})\\"

\\\\ to match a backslash, \\d to match digits, {4,5} for "4 to 5". The parentheses around \\d{4,5} make it so that you can access the number part with .Groups[1] .

Answer 3

试试(\\\\[\\d]{4,5}\\\\)

Answer 4

I've developed a simple tool to verify regexes against example strings; this is a valid string for your samples in C#, it however is not 'strict'!

(?<name>.+?)\\\\(?<ip>[0-9.]+)\\\\(?<port>[0-9]{4,5})\\\\(?<boolean>[False|True]+)

Answer 5

\\[0-9]{4,5}\\

\\ It should start with \\ (another \\ is to escape)
[0-9] It could be any of the number mentioned in set (0,1,2,3...9)
{4,5} previous set can appear 4 to 5 times
\\ It should end with \\ (another \\ is to escape)