java - 如何在 Java/Groovy 中获得最长的连续日和平均日？

Question

我在根据给定 map 计算最长连续天数和平均天数时遇到问题>。

代码片段如下:

def testData = [:] as Map<Long, List<String>>;
testData[1L] = [
   "2015-01-02", "2015-01-03", "2015-01-04", "2015-01-08", "2015-01-09",
   "2015-01-11", "2015-01-12", "2015-01-13", "2015-01-17"];
testData[2L] = [
   "2015-01-01", "2015-01-03", "2015-01-04", "2015-01-08",
   "2015-01-10", "2015-01-13", "2015-01-14"];

List results = [];
testData.each { kv ->

   // something to do here too..
   kv.value.each { dateInString ->
      // 1. convert string to date
      // 2. calculate average days
      // 3. calculate longest streak
   }

   results << [
     key: kv.key,
     longestStreak: 0 + " days",
     longestStreakDates: [
        [startDate: "", endDate: ""], [more..]
     ],
     averageDay: 0 + " days"
   ]
}

results.each { it ->
   println "${it.key} | Longest streak: ${it.longestStreak} | Average Day: ${it.averageDay}";
   println "Longest streak dates:";
   it.longestStreakDates.eachWithIndex { dateStreak, index ->
       println "\t\t${index}. ${dateStreak.startDate} - ${dateStreak.endDate}";
   }
}

first 键 ID 的平均天数计算: 1. 平均天数:(3 天 + 2 天 + 3 天 + 1 天)/4(连续天数)= 9 天/4 = 2.25 天

second 键 ID 的平均天数计算:2。平均天数:(1 天 + 2 天 + 1 天 + 1 天 + 2 天)/5(连续天数)= 7天/5 = 1.4 天

Longest Streak计算请看http://www.quora.com/What-is-your-longest-streak-on-GitHub

上面的代码片段最终会打印成这样:

1 | Longest streak: 3 days | Average Day: 2.25 days.
Longest streak dates:
     1. 2015-01-02 - 2015-01-04
2 | Longest streak: 2 days | Average Day: 1.4 days.
Longest streak dates:
     1. 2015-01-03 - 2015-01-04
     2. 2015-01-13 - 2015-01-14

谁能帮我在每个循环“这里也要做点什么……”中实现逻辑？我使用的数据模型是否过于复杂或难以实现？如果有人有更好、更有效的方法来解决这个问题，请告诉我。

此外，除了“平均”计算，我可能还需要“众数”和“中位数”计算。

谢谢。

Answer 1

给你:

import java.util.Calendar

def testData = [
    1L:[
       "2015-01-02", "2015-01-03", "2015-01-04", "2015-01-08", "2015-01-09",
       "2015-01-11", "2015-01-12", "2015-01-13", "2015-01-17"
    ],
    2L:[
       "2015-01-01", "2015-01-03", "2015-01-04", "2015-01-08",
       "2015-01-10", "2015-01-13", "2015-01-14"
    ]
]
testData.each { k, v ->
    def daysOfYear = v.collect { d -> Date.parse('yyyy-MM-dd', d) }.sort().collect { it[Calendar.DAY_OF_YEAR] }
    //println(daysOfYear)
    def streaks = [:]
    def streakIdx = 0
    def streakCnt = 1
    for(int i = 0; i < daysOfYear.size(); i++) {
        if(daysOfYear[i] + 1 == daysOfYear[i+1]) {
            streakCnt++
        } else {
           streaks[streakIdx++] = streakCnt
           streakCnt = 1 
        }
    }
    def max = streaks.values().max()
    def avg = streaks.values().sum() / streaks.values().size()
    println("Key: $k, max: $max, avg: $avg")
}