在 Go 中进行日期比较有什么选择吗?我必须根据日期和时间对数据进行排序 - 独立。所以我可能允许一个对象出现在一个日期范围内,只要它也出现在一个时间范围内。在这个模型中,我不能简单地选择最早的日期、最年轻的时间/最晚日期、最晚时间和 Unix() 秒来比较它们。我真的很感激任何建议。
最终,我编写了一个时间解析字符串比较模块来检查时间是否在一个范围内。然而,这并不顺利。我有一些悬而未决的问题。我会在这里发布它只是为了好玩,但我希望有更好的时间比较方法。
package main
import (
"strconv"
"strings"
)
func tryIndex(arr []string, index int, def string) string {
if index <= len(arr)-1 {
return arr[index]
}
return def
}
/*
* Takes two strings of format "hh:mm:ss" and compares them.
* Takes a function to compare individual sections (split by ":").
* Note: strings can actually be formatted like "h", "hh", "hh:m",
* "hh:mm", etc. Any missing parts will be added lazily.
*/
func timeCompare(a, b string, compare func(int, int) (bool, bool)) bool {
aArr := strings.Split(a, ":")
bArr := strings.Split(b, ":")
// Catches margins.
if (b == a) {
return true
}
for i := range aArr {
aI, _ := strconv.Atoi(tryIndex(aArr, i, "00"))
bI, _ := strconv.Atoi(tryIndex(bArr, i, "00"))
res, flag := compare(aI, bI)
if res {
return true
} else if flag { // Needed to catch case where a > b and a is the lower limit
return false
}
}
return false
}
func timeGreaterEqual(a, b int) (bool, bool) {return a > b, a < b}
func timeLesserEqual(a, b int) (bool, bool) {return a < b, a > b}
/*
* Returns true for two strings formmated "hh:mm:ss".
* Note: strings can actually be formatted like "h", "hh", "hh:m",
* "hh:mm", etc. Any missing parts will be added lazily.
*/
func withinTime(timeRange, time string) bool {
rArr := strings.Split(timeRange, "-")
if timeCompare(rArr[0], rArr[1], timeLesserEqual) {
afterStart := timeCompare(rArr[0], time, timeLesserEqual)
beforeEnd := timeCompare(rArr[1], time, timeGreaterEqual)
return afterStart && beforeEnd
}
// Catch things like `timeRange := "22:00:00-04:59:59"` which will happen
// with UTC conversions from local time.
// THIS IS THE BROKEN PART I BELIEVE
afterStart := timeCompare(rArr[0], time, timeLesserEqual)
beforeEnd := timeCompare(rArr[1], time, timeGreaterEqual)
return afterStart || beforeEnd
}
所以 TLDR,我写了一个 withinTimeRange(range, time) 函数,但它不能完全正常工作。(事实上,大多数情况下,时间范围跨越几天的情况被破坏了。原始部分有效,我刚刚意识到在从本地转换为 UTC 时需要考虑这一点。)
如果有更好的(最好是内置的)方式,我很想听听!
注意:作为一个例子,我用这个函数在 Javascript 中解决了这个问题:
function withinTime(start, end, time) {
var s = Date.parse("01/01/2011 "+start);
var e = Date.parse("01/0"+(end=="24:00:00"?"2":"1")+"/2011 "+(end=="24:00:00"?"00:00:00":end));
var t = Date.parse("01/01/2011 "+time);
return s <= t && e >= t;
}
但是我真的很想在服务器端做这个过滤器。