通过正则表达式采摘范围百分比

Question

我正在接受用户输入的字符串并尝试确定它是否与正则表达式匹配。如果是这样，我需要从输入中提取某些匹配的组并处理它们。

有效的字符串必须是以下形式：

1个可以由整数或浮点数（小数点）组成的数字
后跟一个连字符 ("-")
后跟另一个数字（与第一个相同）
可选以百分号结尾（“%”）

有效字符串输入示例：

"6-9"
"6.5-9"
"6-9.24"
“6-9%”
“6.5-9%”
"6.24-9.23%"

我最好的尝试：

String numRange = getFromUser();
Pattern pattern = Pattern.compile("([0-9]{1,2}\.[0-9]{1,2})-([0-9]{1,2}\.[0-9]{1,2})[%]*");
Matcher matcher = pattern.matcher(numRange);
if (matcher.matches()) {
    String lowRangeVal = matcher.group(1);
    String highRangeVal = matcher.group(2);

    // continue processing here
}

无效。谁能发现我哪里出错了？

Answer 1

我修改了您的模式以满足您的要求，如下所示。

([0-9]{1,2}(\.[0-9]{1,2})*)-([0-9]{1,2}(\.[0-9]{1,2})*)[%]*

我只在小数点和第二个数字部分添加了可选的（*）。而且我假设小数点前后的数字限制为1到2的长度，虽然你没有这么说

https://regex101.com/r/5fpUB2/1

Answer 2

使用

Pattern pattern = Pattern.compile("(\d+(?:\.\d+)?)-(\d+(?:\.\d+)?)%*");

参见regex proof。

解释

--------------------------------------------------------------------------------
  (                        group and capture to :
--------------------------------------------------------------------------------
    \d+                      digits (0-9) (1 or more times (matching
                             the most amount possible))
--------------------------------------------------------------------------------
    (?:                      group, but do not capture (optional
                             (matching the most amount possible)):
--------------------------------------------------------------------------------
      \.                       '.'
--------------------------------------------------------------------------------
      \d+                      digits (0-9) (1 or more times
                               (matching the most amount possible))
--------------------------------------------------------------------------------
    )?                       end of grouping
--------------------------------------------------------------------------------
  )                        end of 
--------------------------------------------------------------------------------
  -                        '-'
--------------------------------------------------------------------------------
  (                        group and capture to :
--------------------------------------------------------------------------------
    \d+                      digits (0-9) (1 or more times (matching
                             the most amount possible))
--------------------------------------------------------------------------------
    (?:                      group, but do not capture (optional
                             (matching the most amount possible)):
--------------------------------------------------------------------------------
      \.                       '.'
--------------------------------------------------------------------------------
      \d+                      digits (0-9) (1 or more times
                               (matching the most amount possible))
--------------------------------------------------------------------------------
    )?                       end of grouping
--------------------------------------------------------------------------------
  )                        end of 
--------------------------------------------------------------------------------
  %*                       '%' (0 or more times (matching the most
                           amount possible))

通过正则表达式采摘范围百分比

Plucking ranged percentages via regex

java

regex

java-8