Replaces the first substring of this string that matches the given regular expression with the given replacement.

An invocation of this method of the form str .replaceFirst(regex , repl ) yields exactly the same result as the expression

java.util.regex.Pattern.compile(regex).matcher(str).replaceFirst(repl)

Note that backslashes ( \) and dollar signs ( $) in the replacement string may cause the results to be different than if it were being treated as a literal replacement string; see java.util.regex.Matcher.replaceFirst. Use java.util.regex.Matcher.quoteReplacement to suppress the special meaning of these characters, if desired.

Parameters:

regex the regular expression to which this string is to be matched

replacement the string to be substituted for the first match

Returns: The resulting String

Exceptions:

PatternSyntaxException if the regular expression's syntax is invalid

`regex`		the regular expression to which this string is to be matched
`replacement`		the string to be substituted for the first match