Clojure:获取正则表达式匹配列表

Question

也许我说这一切都错了,但我正在尝试将字符串中的所有匹配项用于特定的正则表达式模式.我正在使用re-matcherMatch对象,我传递给它re-find,给我(full-string-match,grouped-text)对.我如何得到Match对象产生的所有匹配序列？

在Clojuresque Python中,它看起来像:

pairs = []
match = re-matcher(regex, line)

while True:
    pair = re-find(match)
    if not pair: break
    pairs.append(pair)

有什么建议？

Answer 1

您可能希望使用内置的re-seq和Clojure内置的正则表达式文字.除非你真的有,否则不要乱用底层的java对象.

(doc re-seq)

clojure.core/re-seq
([re s])
  Returns a lazy sequence of successive matches of pattern in string,
  using java.util.regex.Matcher.find(), each such match processed with
  re-groups. 

For example:

user> (re-seq #"the \w+" "the cat sat on the mat")
("the cat" "the mat")

In answer to the follow-up comment, group captures will result in a vector of strings with an element for each part of the group in a match:

user> (re-seq #"the (\w+(t))" "the cat sat on the mat")
(["the cat" "cat" "t"] ["the mat" "mat" "t"])

You can extract a specific element by taking advantage of the elegant fact that vectors are functions of their indices.

user> (defn extract-group [n] (fn [group] (group n)))
#'user/extract-group
user> (let [matches (re-seq #"the (\w+(t))" "the cat sat on the mat")]
       (map (extract-group 1) matches))
("cat" "mat")

Or you can destructure the matches (here using a for宏来遍历所有匹配,但这也可以在一个let或函数参数绑定中完成):

user> (dorun 
        (for [[m1 m2 m3] (re-seq #"the (\w+(t))" "the cat sat on the mat")]  
          (do (println "m1:" m1) 
              (println "m2:" m2) 
              (println "m3:" m3))))
m1: the cat
m2: cat
m3: t
m1: the mat
m2: mat
m3: t