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我有一个这种格式的日期：Wdy, DD-Mon-YY HH:MM:SS GMT我需要对其进行解析并将其转换为struct std.date.Date或等价于。我通过使用split()s 调用编写了一个非常简单的函数（请查看我的代码下方）。

问题在于性能——我正在寻找一种更快的算法来做到这一点。拆分令牌后，我使用to!int(tok)转换为int并放入结构中。有没有最好的方法呢？如果不太复杂，请建议内置 D 函数或一些外部模块。

注意：我是一名 C 程序员，从 D 编程语言开始。因此，您将看到一些 C-way 解决方案。

struct MyDate {
  int day;
  int month;
  int year;
  int hour;
  int minute;
  int second;
  //int ms;

};

int index_of_month(string mont) 
{

  immutable string[] months = ["jan", "feb", "mar", "apr", "may", "jun", "jul", "aug", "sep", "oct", "nov", "dec"];

  for(int i = 0, len = months.length; i < len; ++i)
    if(months[i] == mont) 
      return i;

  return -1;
}

void main()
{
  //date format Wdy, DD-Mon-YY HH:MM:SS GMT
  string d = "Sun, 24-Aug-2014 15:00:24 GMT";
  string[] parts = split(d, " ");
  string[] _date = split(parts[1], "-");
  string[] _hour = split(parts[2], ":");

  debug { 
    for(int i = 0; i < parts.length; ++i)
      writefln("[%d]: %s", i, parts[i]);

  } else {

    //Handling erros goes here
    //...

    //I write my onw date struct because
    // std.date.Date cannot be compiled 
    // even by using -d flag; and std.datetime.Date is not equivalent to.
    // NOTE: I think that I will have problems when try to compare it 
    // to Clock.currTime()..
    MyDate date;

    //as you can seed below, I did a lot of 
    // string to integer conversion;
    // I don't know much aboud D, but I think
    // that it's so slow. I'm looking for a best 
    // solution(in perfomance questions).
    date.day    =  to!int(_date[0]); // 0 .. 31 min/max 2 digits.

    //I know about enum Month from std.datatime;
    // but there is no(as far as I know) equivalent to Enum.GetValues()/Enum.GetNames()
    // of C#.NET and .indexOf(), so I write my onw implemantation...
    date.month  =  index_of_month(toLower(_date[1])); // 1 .. 12 min/max 2 digits.

    //maybe do it by using e.g(C-way), 
    // int n = 0; n = (n * 10) + (_date[2][0] - '0'); n = (n * 10) + (_date[2][0] - '0'); and so..
    // and lave the compiler do promotion 
    // can be better?
    date.year   =  to!int(_date[2]); // min 2, max 4 digits. 
    date.hour   =  to!int(_hour[0]); // 0 .. 23 min/max 2 digits.
    date.minute =  to!int(_hour[1]); // 0 .. 59 min/max 2 digits.
    date.second =  to!int(_hour[2]); // 0 .. 59 min/max 2 digits.

    writefln("date.day = %d\n"
         "date.month = %d\n"
         "date.year = %d\n"
         "date.hour = %d\n"
         "date.minute = %d\n"
         "date.second = %d\n",
         date.day, date.month,
         date.year, date.hour,
         date.minute, date.second);


  }

}
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1 回答 1

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这就是我想出的：

import std.stdio;
import std.format;
import std.string;
import std.datetime;
import std.algorithm;

enum MONTHS = ["jan", "feb", "mar", "apr", "may", "jun", "jul", "aug", "sep", "oct", "nov", "dec"];

int month_to_index(string month) {
    return cast(int)MONTHS.countUntil(month.toLower());
}

void main() {
    string date = "Sun, 24-Aug-2014 15:00:24 GMT";

    string a;
    int day;
    string month;
    int year;
    int hour;
    int minute;
    int second;
    string tz;

    date.formattedRead("%s, %d-%s-%d %d:%d:%d %s", &a, &day, &month, &year, &hour, &minute, &second, &tz);

    DateTime dt = DateTime(year, month.month_to_index(), day, hour, minute, second);

    writeln(dt);
}

std.datetime真的需要某种strptimeand strftime。

于 2012-08-25T12:51:35.580 回答