Question

string = "Jack and Jill went up the hill to fetch a pail of water. Jack fell down and broke his crown. And Jill came tumbling after. "
d = string.match(/(jack|jill)/i) # -> MatchData "Jill" 1:"Jill"
d.size # -> 1

这只匹配它出现的第一次出现。
string.scan部分完成了这项工作，但它没有说明匹配模式的索引。

如何获得模式及其索引（位置）的所有匹配实例的列表？

Answer 1

您可以使用.scan和$`全局变量，这意味着上一次成功匹配项左侧的字符串，但它在通常{{}内部不起作用1}}，所以你需要这个 hack （从this answer偷来）：

.scan

输出：

string = "Jack and Jill went up the hill to fetch a pail of water. Jack fell down and broke his crown. And Jill came tumbling after. "  
string.to_enum(:scan, /(jack|jill)/i).map do |m,|
  p [$`.size, m]
end

<强> UPD：

注意lookbehind的行为 - 你得到真正匹配的部分的索引，而不是看起来一个：

[0, "Jack"]
[9, "Jill"]
[57, "Jack"]
[97, "Jill"]

Answer 2

如果您只想提供＆＃34; Jack＆＃34;的位置，那么这是对Nakilon答案的修改。成阵列

location_array = Array.new

string = "Jack and Jack went up the hill to fetch a pail of Jack..."  
string.to_enum(:scan,/(jack)/i).map do |m,|
    location_array.push [$`.size]
end

如何获取字符串中所有出现的模式的索引

2 个答案: