给定特定的DateTime值,如何显示相对时间,例如:
2小时前3天前一个月前
给定特定的DateTime值,如何显示相对时间,例如:
2小时前3天前一个月前
当前回答
这是stackoverflow使用的算法,但使用了错误修复(没有“一小时前”)的perlish伪代码进行了更简洁的重写。该函数在秒前取一个(正数),并返回一个人类友好的字符串,如“3小时前”或“昨天”。
agoify($delta)
local($y, $mo, $d, $h, $m, $s);
$s = floor($delta);
if($s<=1) return "a second ago";
if($s<60) return "$s seconds ago";
$m = floor($s/60);
if($m==1) return "a minute ago";
if($m<45) return "$m minutes ago";
$h = floor($m/60);
if($h==1) return "an hour ago";
if($h<24) return "$h hours ago";
$d = floor($h/24);
if($d<2) return "yesterday";
if($d<30) return "$d days ago";
$mo = floor($d/30);
if($mo<=1) return "a month ago";
$y = floor($mo/12);
if($y<1) return "$mo months ago";
if($y==1) return "a year ago";
return "$y years ago";
其他回答
我的方法要简单得多。您可以根据需要调整返回字符串
public static string TimeLeft(DateTime utcDate)
{
TimeSpan timeLeft = DateTime.UtcNow - utcDate;
string timeLeftString = "";
if (timeLeft.Days > 0)
{
timeLeftString += timeLeft.Days == 1 ? timeLeft.Days + " day" : timeLeft.Days + " days";
}
else if (timeLeft.Hours > 0)
{
timeLeftString += timeLeft.Hours == 1 ? timeLeft.Hours + " hour" : timeLeft.Hours + " hours";
}
else
{
timeLeftString += timeLeft.Minutes == 1 ? timeLeft.Minutes+" minute" : timeLeft.Minutes + " minutes";
}
return timeLeftString;
}
在PHP中,我是这样做的:
<?php
function timesince($original) {
// array of time period chunks
$chunks = array(
array(60 * 60 * 24 * 365 , 'year'),
array(60 * 60 * 24 * 30 , 'month'),
array(60 * 60 * 24 * 7, 'week'),
array(60 * 60 * 24 , 'day'),
array(60 * 60 , 'hour'),
array(60 , 'minute'),
);
$today = time(); /* Current unix time */
$since = $today - $original;
if($since > 604800) {
$print = date("M jS", $original);
if($since > 31536000) {
$print .= ", " . date("Y", $original);
}
return $print;
}
// $j saves performing the count function each time around the loop
for ($i = 0, $j = count($chunks); $i < $j; $i++) {
$seconds = $chunks[$i][0];
$name = $chunks[$i][1];
// finding the biggest chunk (if the chunk fits, break)
if (($count = floor($since / $seconds)) != 0) {
break;
}
}
$print = ($count == 1) ? '1 '.$name : "$count {$name}s";
return $print . " ago";
} ?>
using System;
using System.Collections.Generic;
using System.Linq;
public static class RelativeDateHelper
{
private static Dictionary<double, Func<double, string>> sm_Dict = null;
private static Dictionary<double, Func<double, string>> DictionarySetup()
{
var dict = new Dictionary<double, Func<double, string>>();
dict.Add(0.75, (mins) => "less than a minute");
dict.Add(1.5, (mins) => "about a minute");
dict.Add(45, (mins) => string.Format("{0} minutes", Math.Round(mins)));
dict.Add(90, (mins) => "about an hour");
dict.Add(1440, (mins) => string.Format("about {0} hours", Math.Round(Math.Abs(mins / 60)))); // 60 * 24
dict.Add(2880, (mins) => "a day"); // 60 * 48
dict.Add(43200, (mins) => string.Format("{0} days", Math.Floor(Math.Abs(mins / 1440)))); // 60 * 24 * 30
dict.Add(86400, (mins) => "about a month"); // 60 * 24 * 60
dict.Add(525600, (mins) => string.Format("{0} months", Math.Floor(Math.Abs(mins / 43200)))); // 60 * 24 * 365
dict.Add(1051200, (mins) => "about a year"); // 60 * 24 * 365 * 2
dict.Add(double.MaxValue, (mins) => string.Format("{0} years", Math.Floor(Math.Abs(mins / 525600))));
return dict;
}
public static string ToRelativeDate(this DateTime input)
{
TimeSpan oSpan = DateTime.Now.Subtract(input);
double TotalMinutes = oSpan.TotalMinutes;
string Suffix = " ago";
if (TotalMinutes < 0.0)
{
TotalMinutes = Math.Abs(TotalMinutes);
Suffix = " from now";
}
if (null == sm_Dict)
sm_Dict = DictionarySetup();
return sm_Dict.First(n => TotalMinutes < n.Key).Value.Invoke(TotalMinutes) + Suffix;
}
}
与此问题的另一个答案相同,但作为静态字典的扩展方法。
public static string RelativeDate(DateTime theDate)
{
Dictionary<long, string> thresholds = new Dictionary<long, string>();
int minute = 60;
int hour = 60 * minute;
int day = 24 * hour;
thresholds.Add(60, "{0} seconds ago");
thresholds.Add(minute * 2, "a minute ago");
thresholds.Add(45 * minute, "{0} minutes ago");
thresholds.Add(120 * minute, "an hour ago");
thresholds.Add(day, "{0} hours ago");
thresholds.Add(day * 2, "yesterday");
thresholds.Add(day * 30, "{0} days ago");
thresholds.Add(day * 365, "{0} months ago");
thresholds.Add(long.MaxValue, "{0} years ago");
long since = (DateTime.Now.Ticks - theDate.Ticks) / 10000000;
foreach (long threshold in thresholds.Keys)
{
if (since < threshold)
{
TimeSpan t = new TimeSpan((DateTime.Now.Ticks - theDate.Ticks));
return string.Format(thresholds[threshold], (t.Days > 365 ? t.Days / 365 : (t.Days > 0 ? t.Days : (t.Hours > 0 ? t.Hours : (t.Minutes > 0 ? t.Minutes : (t.Seconds > 0 ? t.Seconds : 0))))).ToString());
}
}
return "";
}
我更喜欢这个版本,因为它简洁,并且能够添加新的刻度点。这可以用Timespan的Latest()扩展来封装,而不是长的1行,但为了发布的简洁,这可以。这修复了一小时前、一小时前的问题,提供了一个小时直到两小时过去
我想我应该用类和多态性来尝试一下。我以前的迭代使用了子类,结果开销太大。我已经切换到一个更灵活的委托/公共属性对象模型,这明显更好。我的代码稍微准确一点,我希望我能想出一种更好的方法来生成“几个月前”的代码,而这种方法看起来并没有过度设计。
我想我还是会坚持Jeff的if-then-cascade,因为它的代码更少,而且更简单(肯定更容易确保它按预期工作)。
对于以下代码,PrintRelativeTime.GetRelativeTime message(TimeSpan ago)返回相对时间消息(例如“昨天”)。
public class RelativeTimeRange : IComparable
{
public TimeSpan UpperBound { get; set; }
public delegate string RelativeTimeTextDelegate(TimeSpan timeDelta);
public RelativeTimeTextDelegate MessageCreator { get; set; }
public int CompareTo(object obj)
{
if (!(obj is RelativeTimeRange))
{
return 1;
}
// note that this sorts in reverse order to the way you'd expect,
// this saves having to reverse a list later
return (obj as RelativeTimeRange).UpperBound.CompareTo(UpperBound);
}
}
public class PrintRelativeTime
{
private static List<RelativeTimeRange> timeRanges;
static PrintRelativeTime()
{
timeRanges = new List<RelativeTimeRange>{
new RelativeTimeRange
{
UpperBound = TimeSpan.FromSeconds(1),
MessageCreator = (delta) =>
{ return "one second ago"; }
},
new RelativeTimeRange
{
UpperBound = TimeSpan.FromSeconds(60),
MessageCreator = (delta) =>
{ return delta.Seconds + " seconds ago"; }
},
new RelativeTimeRange
{
UpperBound = TimeSpan.FromMinutes(2),
MessageCreator = (delta) =>
{ return "one minute ago"; }
},
new RelativeTimeRange
{
UpperBound = TimeSpan.FromMinutes(60),
MessageCreator = (delta) =>
{ return delta.Minutes + " minutes ago"; }
},
new RelativeTimeRange
{
UpperBound = TimeSpan.FromHours(2),
MessageCreator = (delta) =>
{ return "one hour ago"; }
},
new RelativeTimeRange
{
UpperBound = TimeSpan.FromHours(24),
MessageCreator = (delta) =>
{ return delta.Hours + " hours ago"; }
},
new RelativeTimeRange
{
UpperBound = TimeSpan.FromDays(2),
MessageCreator = (delta) =>
{ return "yesterday"; }
},
new RelativeTimeRange
{
UpperBound = DateTime.Now.Subtract(DateTime.Now.AddMonths(-1)),
MessageCreator = (delta) =>
{ return delta.Days + " days ago"; }
},
new RelativeTimeRange
{
UpperBound = DateTime.Now.Subtract(DateTime.Now.AddMonths(-2)),
MessageCreator = (delta) =>
{ return "one month ago"; }
},
new RelativeTimeRange
{
UpperBound = DateTime.Now.Subtract(DateTime.Now.AddYears(-1)),
MessageCreator = (delta) =>
{ return (int)Math.Floor(delta.TotalDays / 30) + " months ago"; }
},
new RelativeTimeRange
{
UpperBound = DateTime.Now.Subtract(DateTime.Now.AddYears(-2)),
MessageCreator = (delta) =>
{ return "one year ago"; }
},
new RelativeTimeRange
{
UpperBound = TimeSpan.MaxValue,
MessageCreator = (delta) =>
{ return (int)Math.Floor(delta.TotalDays / 365.24D) + " years ago"; }
}
};
timeRanges.Sort();
}
public static string GetRelativeTimeMessage(TimeSpan ago)
{
RelativeTimeRange postRelativeDateRange = timeRanges[0];
foreach (var timeRange in timeRanges)
{
if (ago.CompareTo(timeRange.UpperBound) <= 0)
{
postRelativeDateRange = timeRange;
}
}
return postRelativeDateRange.MessageCreator(ago);
}
}