How to sort by time.Time - go

Question

I am trying to sort struct in Go by its member which is of type time.Time.
the structure is as follows.
type reviews_data struct {
review_id string
date time.Time
score int
firstname string
anonymous bool
review_text string
title_text string
rating float64
upcount int
}
I have the below functions for sorting
type timeSlice []reviews_data
// Forward request for length
func (p timeSlice) Len() int {
return len(p)
}
// Define compare
func (p timeSlice) Less(i, j int) bool {
return p[i].date.Before(p[j].date)
}
// Define swap over an array
func (p timeSlice) Swap(i, j int) {
p[i], p[j] = p[j], p[i]
}
A map is defined as follows
var reviews_data_map = make(map[string]reviews_data)
After the map gets filled with values,sorting of the map by values is done as below
//Sort the map by date
date_sorted_reviews := make(timeSlice, 0, len(reviews_data_map))
for _, d := range reviews_data_map {
date_sorted_reviews = append(date_sorted_reviews, d)
}
sort.Sort(date_sorted_reviews)
The problem is that the result is not sorted.Can anyone tell me what the problem is.

Answer 1

Go 1.8 and above:
sort.Slice(timeSlice, func(i, j int) bool {
return timeSlice[i].date.Before(timeSlice[j].date)
})

Answer 2

It looks sorted to me:
package main
import (
"fmt"
"sort"
"time"
)
type reviews_data struct {
review_id string
date time.Time
score int
firstname string
anonymous bool
review_text string
title_text string
rating float64
upcount int
}
type timeSlice []reviews_data
func (p timeSlice) Len() int {
return len(p)
}
func (p timeSlice) Less(i, j int) bool {
return p[i].date.Before(p[j].date)
}
func (p timeSlice) Swap(i, j int) {
p[i], p[j] = p[j], p[i]
}
func main() {
var reviews_data_map = make(map[string]reviews_data)
reviews_data_map["1"] = reviews_data{date: time.Now().Add(12 * time.Hour)}
reviews_data_map["2"] = reviews_data{date: time.Now()}
reviews_data_map["3"] = reviews_data{date: time.Now().Add(24 * time.Hour)}
//Sort the map by date
date_sorted_reviews := make(timeSlice, 0, len(reviews_data_map))
for _, d := range reviews_data_map {
date_sorted_reviews = append(date_sorted_reviews, d)
}
fmt.Println(date_sorted_reviews)
sort.Sort(date_sorted_reviews)
fmt.Println(date_sorted_reviews)
}
Output:
[{ {63393534000 0 0x1ba3e0} 0 false 0 0} { {63393490800 0 0x1ba3e0} 0 false 0 0} { {63393577200 0 0x1ba3e0} 0 false 0 0}]
[{ {63393490800 0 0x1ba3e0} 0 false 0 0} { {63393534000 0 0x1ba3e0} 0 false 0 0} { {63393577200 0 0x1ba3e0} 0 false 0 0}]

Answer 3

This can be done below go 1.8 without the extra type and map in the accepted answer.
package main
import (
"fmt"
"time"
"sort"
)
type reviews_data struct {
review_id string
date time.Time
}
func main() {
fmt.Println("Sort Example")
var listOfReviews = make([]reviews_data, 0)
listOfReviews = append(listOfReviews, reviews_data{review_id: "1",date:time.Now()})
listOfReviews = append(listOfReviews, reviews_data{review_id: "2",date: time.Now().AddDate(0, 0, 7*1)})
listOfReviews = append(listOfReviews, reviews_data{review_id: "1",date: time.Now().AddDate(0, 0, 7*-1)})
sort.Slice(listOfReviews, func(i, j int) bool { return listOfReviews[i].date.Before(listOfReviews[j].date) })
}

Answer 4

sorting dates
type Location struct {
Lat float64 `json:"lat"`
Lng float64 `json:"lng"`
Thetime time.Time `json:"thetime"`
}
func sorttime(dat []Location) {
for i := 0; i < len(dat); i++ {
for j := i + 1; j < len(dat); j++ {
if dat[i].Thetime.Unix() < dat[j].Thetime.Unix() {
dat[i], dat[j] = dat[j], dat[i]
}
}
}
}