[英]replace last dot in a string with a dollar sign
I would like to replace the last dot in the following string with a dollar sign, how can I do that?我想用美元符号替换以下字符串中的最后一个点,我该怎么做?
de.java_chess.javaChess.game.GameImpl.GameStatus
I would like to have de.java_chess.javaChess.game.GameImpl$GameStatus
instead.我想
de.java_chess.javaChess.game.GameImpl$GameStatus
。
I am using the following line of code to do so:我正在使用以下代码行来执行此操作:
invokedMeth = invokedMeth.replaceAll("(.*)\\.(\\d+)$","$1$$2");
However, this doesn't work and I end up with the same original string that I had as an input.但是,这不起作用,我最终得到了与输入相同的原始字符串。 How can I fix this?
我怎样才能解决这个问题?
For this requirement, I would use a non-regex solution that can be easier to understand as well as more efficient.对于这个要求,我会使用一个非正则表达式的解决方案,它更容易理解并且效率更高。
StringBuilder invokedMethSb = new StringBuilder(invokedMeth);
invokedMethSb.setCharAt(invokedMethSb.lastIndexOf("."), '$');
invokedMeth = invokedMethSb.toString();
/*de.java_chess.javaChess.game.GameImpl$GameStatus*/
StringBuilder has some good utils for these operations, such as setCharAt
. StringBuilder对这些操作有一些很好的工具,例如
setCharAt
。
As a personal opinion, I prefer the following one:作为个人意见,我更喜欢以下一个:
char[] invokedArray = invokedMeth.toCharArray();
invokedArray[invokedMeth.lastIndexOf(".")]='$';
invokedMeth = new String(invokedArray);
/*de.java_chess.javaChess.game.GameImpl$GameStatus*/
Regex solution:正则表达式解决方案:
You can use the Positive Lookahead , (?=([^.]*)$)
where ([^.]*)
matches any number of non-dot (ie [^.]
) character and $
asserts position at the end of a line.您可以使用Positive Lookahead ,
(?=([^.]*)$)
其中([^.]*)
匹配任意数量的非点(即[^.]
)字符和$
在末尾断言 position一条线。 You can check regex101.com for more explanation.您可以查看regex101.com以获得更多说明。
public class Main {
public static void main(String[] args) {
String str = "de.java_chess.javaChess.game.GameImpl.GameStatus";
str = str.replaceAll("\\.(?=([^.]*)$)", "\\$");
System.out.println(str);
}
}
Output: Output:
de.java_chess.javaChess.game.GameImpl$GameStatus
A proper regular expression can also help with this replacement:适当的正则表达式也可以帮助进行这种替换:
String withDot = "de.java_chess.javaChess.game.GameImpl.GameStatus";
String with$ = withDot.replaceFirst("(\\w+(\\.\\w+)*)(\\.(\\w+))", "$1\\$$4");
System.out.println(with$);
Output online demo : Output在线演示:
de.java_chess.javaChess.game.GameImpl$GameStatus
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