oi. gostaria muito de saber porque usa esse trecho de códiog? para que ele serve? matcher.replaceFirst("$1");

Dúvida basica sobre REGEX - expressao regular

1 Resposta

AndreSorge 24 de jan. de 2013

Boa Tarde!

Estou colocando o link da documentação de java, é bem fácil e rápido procurar alguma coisa quando se tem uma dúvida em relação a algum método ou o que ele faz.

http://docs.oracle.com/javase/6/docs/api/

Segue o trecho que diz a respeito do replaceFirst:

replaceFirst

public String replaceFirst(String regex,
String replacement)

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

    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 Matcher.replaceFirst(java.lang.String). Use Matcher.quoteReplacement(java.lang.String) 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 
Throws:
    PatternSyntaxException - if the regular expression's syntax is invalid
Since:
    1.4
See Also:
    Pattern

1 Resposta

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