在Scala中的给定索引之后在字符串中查找正则表达式匹配 [英] Find regular expression match in string after a given index in Scala

问题描述

我想为字符串上的正则表达式找到匹配项(如果有)，但只在给定索引之后进行测试.例如:

I want to find a match (if any) for a regular expression on a string, but only testing after a given index. For example:

val p = "[a-zA-Z_][a-zA-Z0-9_]*".r
val t = "const pi = 3.141592"
val m = p.findFirstMatchIn(t, start=5) // not real syntax

也就是说，我想忽略字符串的前 n = 5 个字符.有没有办法做到这一点?

That is, I want to ignore the first n = 5 characters of the string. Is there any way to do that?

推荐答案

Scala 的 .r 语法是原始 java.util.regex.{Pattern, Matcher} API.原始 API 提供更多控制.使用 <代码>Matcher.region:

Scala's .r syntax is a thin wrapper around the original java.util.regex.{Pattern, Matcher} API. The original API provides more control. Use Matcher.region:

scala> val m = Pattern.compile("[a-zA-Z_][a-zA-Z0-9_]*").matcher(t)
scala> m.region(5, t.size)
scala> m.find()
scala> m.group(0)
res6: String = pi

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