Clojure中的正则表达式

Question

我希望捕获的日期格式属于"word/DD/YYYY"模式的排列,其中单词对应于月份,即

(def months ["january" "January" "february" "February" "march" "March" "April" "april" "may" "May" "june" "June" "july" "July" "august" "August" "september" "September" "october" "October" "november" "November" "december" "December"])

因此,上述模式的可能排列将是"DD/word/YYYY""YYYY/word/DD"和"YYYY/DD/word"

我尝试了一些方法

(def months-match (clojure.string/join "|" months))
(def months-str (str "(\\s*(" months-match ")")) 
(def moster (re-pattern  months-str))

(defn foomonths [s]
(map first (re-seq moster s)))

计划在几天和几年内添加正则表达式

|[- /.](0[1-9]|[12][0-9]|3[01])[- /.](19|20)\d\d

置换正则表达式不是问题.相反,它是将数月的单词制定成正则表达式结构的过程,其中日期和年份以数字表示.

Answer 1

我看到你的问题是关于正则表达式的,所以如果这个答案不合适,我很抱歉,但如果我可能建议采用略有不同的方法,clj-time包括一个时间格式化程序,它可以处理大多数开箱即用的情况:

project.clj:

 (defproject hello "0.1.0-SNAPSHOT"
  :description "FIXME: write description"
  :url "http://example.com/FIXME"
  :license {:name "Eclipse Public License"
            :url "http://www.eclipse.org/legal/epl-v10.html"}
  :dependencies [[org.clojure/clojure "1.5.1"]
              [clj-time "0.6.0"]]
  :source-paths ["dev"]) 

user> (def custom-formatter (formatter "dd/MMMMMMMMM/YYYY"))
#'user/custom-formatter

user> (parse custom-formatter "14/June/2014")
#<DateTime 2014-06-14T00:00:00.000Z>

user> (parse custom-formatter "14/september/2014")
#<DateTime 2014-09-14T00:00:00.000Z> 

因此,您可以为每个排列编写一个时间格式字符串,然后尝试每个字符串直到您获得匹配