Question

Why isn’t my regular expression finding my string?

 Regex.Replace(" SCRIPT language=Javascript src=\"\"\r\ntype=text/javascript ",
    "^language=Javascript$",
    "language=\"Javascript\"",
    RegexOptions.Multiline | RegexOptions.Compiled
);

the ^language=Javascript$ isn’t working. if I remove it it works, but I want to make sure that a partially similar string doesn’t get replaced (it has happened in my tests). The strings are not constants, I actually using variables, but this is just 1 case that I am using. Any help?

Answer 1

Well, this is because ^ represents the start of the string and $ the end of the string. Your regex simply cannot match. You could use

\blanguage=Javascript\b

as a workaround if you just want to make sure that foolanguage=Javascript doesn’t match. But that depends a little on the data you expect and stuff into that method. A safer way would be

(?<= )language=Javascript(?= )

which would make sure that there is a space before and after the match. You can make it more complex (and reliable) from there, e.g.

(?<= )language=Javascript(?= |>)

to match even <script type='text/javascript' language=Javascript>.