JAVA 去掉字符串最后一个“*”

Question

I want to remove ONLY the last * in the string. For example, abc* should become abc . abc*d*d should become abc*dd .

I checked other solutions, I found:

parameter.replaceAll("a$", "b")

This will replace the last "a" by "b". However, when I change it to this it shows an error:

parameter.replaceAll("*$", "b")

I also tried:

parameter.replaceAll("\\*$", "b")

Answer 1

parameter = parameter.replaceFirst("\\*$", "b");  // "aaa*" to "aaab"
parameter = parameter.replaceFirst("\\*([^*]*)$", "b$1"); // "aa*aa*aa" to "aa*aabaa"

Answer 2

Instead of a performance-heavy regex, you can use lastIndexOf() and substring() , for better performance when used inside a tight loop.

int idx = parameter.lastIndexOf('*');
if (idx != -1)
    parameter = parameter.substring(0, idx).concat(parameter.substring(idx + 1));

Answer 3

Here you could use a greedy (.+) up to the (last occurrence of) * and it should remove what you want. For example:

(.+)\\* (click to see it on regex101)

Answer 4

parameter.replaceAll("[*]([^*]*)$", "$1")
//                    ^^^
//                     A ^^^^^^^
//                          B

Match an asterisk (A) followed by 0 or more non-asterisks (B). The parentheses surrounding B mean that string is captured as $1 . The replacement string only contains $1 , which means that effectively, the asterisk is erased.

Make sure to assign the result to a variable, or print it. replaceAll() doesn't modify parameter in place; it returns the modified string.