I'd like to generate a random timestamp within the last relative 3 years and have it be printed out with this format: %d/%b/%Y:%H:%M:%S %z
Here is what I have right now:
package main
import (
"strconv"
"time"
"math/rand"
"fmt"
)
func randomTimestamp() time.Time {
randomTime := rand.Int63n(time.Now().Unix() - 94608000) + 94608000
randomNow, err := time.Parse("10/Oct/2000:13:55:36 -0700", strconv.FormatInt(randomTime, 10))
if err != nil {
panic(err)
}
return randomNow
}
func main() {
fmt.Println(randomTimestamp().String())
}
This always throws: panic: parsing time "...": month out of range. How can I generate a random timestamp for a given range, then convert it to the string format I want with the standard library?
Don't use time.Parse. You have a Unix time, not a time string. Use the Unix() method instead. https://golang.org/pkg/time/#Unix. You can also choose a minimum time value, say 1/1/1900 and add a random Duration of seconds to the time using the Add method on Time and passing a Duration you made with the Ticks() method. https://golang.org/pkg/time/#Duration
Here's a Go Playground link. Just remember that the Go Playground doesn't support actual randomness. https://play.golang.org/p/qYTpnbml_N
package main
import (
"time"
"math/rand"
"fmt"
)
func randomTimestamp() time.Time {
randomTime := rand.Int63n(time.Now().Unix() - 94608000) + 94608000
randomNow := time.Unix(randomTime, 0)
return randomNow
}
func main() {
fmt.Println(randomTimestamp().String())
}
Related
This question already has answers here:
Convert time.Time to string
(6 answers)
Closed 2 years ago.
I want to get a timestamp as string. If I use string conversion I got no error but the output is not readable.
Later, I want us it as a part of a filename.
It looks like a question mark for e.g. �
I found some examples like this: https://play.golang.org/p/bq2h3h0YKp
not solves completely me problem. thanks
now := time.Now() // current local time
sec := now.Unix() // number of seconds since January 1, 1970 UTC
fmt.Println(string(sec))
How could I get the timestamp as string?
Something like this works for me
package main
import (
"fmt"
"strconv"
"time"
)
func main() {
now := time.Now()
unix := now.Unix()
fmt.Println(strconv.FormatInt(unix, 10))
}
Here are two examples of how you can convert a unix timestamp to a string.
The first example (s1) uses the strconv package and its function FormatInt. The second example (s2) uses the fmt package (documentation) and its function Sprintf.
Personally, I like the Sprintf option more from an aesthetic point of view. I did not check the performance yet.
package main
import "fmt"
import "time"
import "strconv"
func main() {
t := time.Now().Unix() // t is of type int64
// use strconv and FormatInt with base 10 to convert the int64 to string
s1 := strconv.FormatInt(t, 10)
fmt.Println(s1)
// Use Sprintf to create a string with format:
s2 := fmt.Sprintf("%d", t)
fmt.Println(s2)
}
Golang Playground: https://play.golang.org/p/jk_xHYK_5Vu
I'm trying to get the day as a string from a time.Now() instance.
now := time.Now() // .String() would give me the entire date as a string which I don't need
day := now.Day()) // is what I want but as a String.
So string(day) tells me "can not convert day to string".
For me now.Day().String() would be nice but there is no such method...
I could now try to take time.Now().String() and manipulate until the day is left over. But there should be a easier way to do it...
Use strconv to convert int to string
strconv.Itoa(day)
You can import and use strconv as KibGzr mentioned. Just to give a complete example:
package main
import (
"fmt"
"time"
"strconv"
)
func main() {
now := time.Now()
day := now.Day()
fmt.Printf("%T\n",(day))
fmt.Println(strconv.Itoa(day))
dayString := strconv.Itoa(day)
fmt.Printf("%T",(dayString))
}
https://play.golang.org/p/Mqs24FJhCoi
Why does it output false? I was expecting true...
package main
import (
"fmt"
"time"
"gopkg.in/mgo.v2/bson"
)
type S struct {
T time.Time
}
func main() {
t := S{time.Now()}
bytes, _ := bson.Marshal(t)
var dt S
bson.Unmarshal(bytes, &dt)
fmt.Println(dt.T.Equal(t.T))
}
go run the above will output false, why Marshal/Unmarshal doesn't preserve the original value?
Bson stores time with lower precision than a time.Time, the value returned from Bson may not equal the value you stored.
You need to use bson.Now():
package main
import (
"fmt"
"gopkg.in/mgo.v2/bson"
"time"
)
type S struct {
T time.Time
}
func main() {
t := S{bson.Now()}
bytes, _ := bson.Marshal(t)
var dt S
bson.Unmarshal(bytes, &dt)
fmt.Println(dt.T)
fmt.Println(t.T)
fmt.Println(dt.T.Equal(t.T))
}
Output:
$> go run main.go
2018-09-08 10:48:42.45 +0300 MSK
2018-09-08 10:48:42.45 +0300 MSK
true
Is there a way to convert a string (which is essentially a huge number) from string to Big int in Go?
I tried to first convert it into bytes array
array := []byte(string)
Then converting the array into BigInt.
I thought that worked, however, the output was different than the original input. So I'm guessing the conversion didn't do the right thing for some reason.
The numbers I'm dealing with are more than 300 digits long, so I don't think I can use regular int.
Any suggestions of what is the best approach for this?
Package big
import "math/big"
func (*Int) SetString
func (z *Int) SetString(s string, base int) (*Int, bool)
SetString sets z to the value of s, interpreted in the given base, and
returns z and a boolean indicating success. The entire string (not
just a prefix) must be valid for success. If SetString fails, the
value of z is undefined but the returned value is nil.
The base argument must be 0 or a value between 2 and MaxBase. If the
base is 0, the string prefix determines the actual conversion base. A
prefix of “0x” or “0X” selects base 16; the “0” prefix selects base 8,
and a “0b” or “0B” prefix selects base 2. Otherwise the selected base
is 10.
For example,
package main
import (
"fmt"
"math/big"
)
func main() {
n := new(big.Int)
n, ok := n.SetString("314159265358979323846264338327950288419716939937510582097494459", 10)
if !ok {
fmt.Println("SetString: error")
return
}
fmt.Println(n)
}
Playground: https://play.golang.org/p/ZaSOQoqZB_
Output:
314159265358979323846264338327950288419716939937510582097494459
See Example for string to big int conversion.
package main
import (
"fmt"
"log"
"math/big"
)
func main() {
i := new(big.Int)
_, err := fmt.Sscan("18446744073709551617", i)
if err != nil {
log.Println("error scanning value:", err)
} else {
fmt.Println(i)
}
}
Output:
18446744073709551617
How to add 1 sec to the date in golang ? I have:
t := time.Now().Format("2006/02/01 03:04:05")
and want something like below but so far getting mismatched types string and time.Duration error
t1, t2, t3 = t + 1*time.Second, t+3*time.Second, t+2*time.Second
func (t Time) Add(d Duration) Time
https://golang.org/pkg/time/#Time.Add
You are asigning a string to t (the result of calling Format) instead of a Time (the result of calling Now). Here's an working example:
package main
import (
"fmt"
"time"
)
func main() {
t := time.Now()
fmt.Println(t.Format(time.RFC3339))
t = t.Add(time.Second)
fmt.Println(t.Format(time.RFC3339))
}
// prints
// 2017-01-21T16:51:31-05:00
// 2017-01-21T16:51:32-05:00