java - 如何替换字符串中除某些字符之外的所有字符？

Question

public class HelloWorld {
    public static void main(String []args) {
        //replace all char to 1 other then c and g
        String str = "abcdefghijklmnopqrstuvwxyz";
        if (str == null || str.length() == 0) {
            return;
        }
        String answer = str.replaceAll("[^cg]+", "1");
        System.out.println(answer);
    }
}

• 当前输出:1c1g1
• 想要的输出:11c111g111111111111111111

Answer 1

Now here I am getting an output as 1c1g1, but what I want is 11c111g111111111111111111

删除+。这表示“匹配前面的一个或多个”，但您要将这一系列匹配字符替换为一个 1。

所以:

public class HelloWorld {

    public static void main(String []args){
        //replace all char to 1 other then c and g
        String str = "abcdefghijklmnopqrstuvwxyz";
        if (str == null || str.length() == 0) {
            return;
        }
        String answer = str.replaceAll("[^cg]", "1");
        // No + here ------------------------^
        System.out.println(answer);
    }
}

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