使用Regex从HTML /文本文件中提取字符串的一部分

Question

I have a C# regular expression to match author names in a text document that is written as:

"author":"AUTHOR'S NAME"

The regex is as follows:

new Regex("\"author\":\"[A-Za-z0-9]*\\s?[A-Za-z0-9]*")

This returns "author":"AUTHOR'S NAME . However, I don't want the quotation marks or the word Author before. I just want the name.

Could anyone help me get the expected value please?

Answer 1

Use regex groups to get a part of the string. ( ) acts as a capture group and can be accessed by the .Groups field.

.Groups[0] matches the whole string

.Groups[1] matches the first group (and so on)

string pattern = "\"author\":\"([A-Za-z0-9]*\\s?[A-Za-z0-9]*)\"";
var match = Regex.Match("\"author\":\"Name123\"", pattern);
string authorName = match.Groups[1];

Answer 2

You can also use look-around approach to only get a match value:

var txt = "\"author\":\"AUTHOR'S NAME\"";
var rgx = new Regex(@"(?<=""author"":"")[^""]+(?="")");
var result = rgx.Match(txt).Value;

My regex yields 555,020 iterations per second speed with this input string, which should suffice.

result will be AUTHOR'S NAME .

(?<="author":") checks if we have "author":" before the match, [^"]+ looks safe since you only want to match alphanumerics and space between the quotes, and (?=") is checking the trailing quote.