正则表达式Java正则表达式从字符串中删除匹配项

Question

我正在尝试找出如何从字符串中删除找到的匹配项。因此，我的代码示例当前如下所示：

public void checkText() {
    String helper = "985, 913, 123, SomeotherText, MoreText, MoreText";
    Pattern pattern = Pattern.compile("\\b\\d{3}");
    Matcher matcher = pattern.matcher(helper);
    while (matcher.find()) {
        String newtext = "Number: " + matcher.group() + "\n"+ newtext;
        helper.replaceAll(matcher.group(),"");
    }
    newtext = newtext + "________________\n"+ helper;
    editText.setText(newtext);
}

所以我的输入字符串是：985, 913, 123, SomeotherText, MoreText, MoreText

运行代码后，我希望看到以下内容：

Number: 985
Number: 913
Number: 123
________________________
SomeotherText, MoreText, MoreText

任何人都能告诉我我现在的代码有什么问题吗

Answer 1

代码中有一些内容可以更新：

• 您应该将替换的返回设置为helper
• 如果只替换为空字符串，那么替换中的字符串将以, , ,开头，并留下逗号和后面的空格
• 您可以初始化变量String newtext = "";

见a Java demo

您的代码可能如下所示：

String helper = "985, 913, 123, SomeotherText, MoreText, MoreText";
Pattern pattern = Pattern.compile("\\b\\d{3}");
Matcher matcher = pattern.matcher(helper);
String newtext = "";

while (matcher.find()) {
    newtext = "Number: " + matcher.group() + "\n"+ newtext;
    helper = helper.replaceAll(matcher.group() + ", ","");
}
newtext = newtext + "________________\n"+ helper;
System.out.println(newtext);

结果：

Number: 123
Number: 913
Number: 985
________________
SomeotherText, MoreText, MoreText

Answer 2

由于您已经在使用Matcher类，因此也可以使用方法Matcher.appendReplacement进行替换：

public void checkText() {
    String helper = "985, 913, 123, SomeotherText, MoreText, MoreText";
    Pattern pattern = Pattern.compile("\\b\\d{3}, ");
    Matcher matcher = pattern.matcher(helper);
    StringBuffer sb = new StringBuffer();
    while (matcher.find()) {
        System.out.println("Number:"+matcher.group());
        matcher.appendReplacement(sb, "");
    }
    matcher.appendTail(sb);
    System.out.println(sb.toString());
}