在time.Now（）到达时进行循环

问题描述：

Is it possible in Golang to increment a date in a for loop by a given date variable till it reached the current date/ time.Now()

// Start date
t, _ := time.Parse(time.RFC3339, "2018-07-19T12:25:10.8584224+02:00")

// Current date
ct := time.Now()

for d := t; d.Day() == ct.Day(); d = d.AddDate(0, 0, 1) {
    // Print all days between start date and current date 
    fmt.Println(d)
}

I expect that variable d prints out all dates (with time etc.) till it reached the current date

在Golang中是否有可能通过给定的日期变量将for循环中的日期递增，直到达到当前日期 / time.Now（） p>

  //开始日期
t，_：= time.Parse（time.RFC3339，“ 2018-07-19T12：25：10.8584224 + 02  ：00“）
 
 //当前日期
ct：=时间。Now（）
 
 for d：= t;  d.Day（）== ct.Day（）;  d = d.AddDate（0，0，1）{
 //打印开始日期和当前日期之间的所有日期
 fmt.Println（d）
} 
  code>  pre> 
 \  n 我希望变量d打印出所有日期（包括时间等），直到达到当前日期为止 p> 
  div>

答

according to godoc: https://golang.org/pkg/time/#Time.Day

func (t Time) Day() int

Day returns the day of the month specified by t.

So comparing d.Day() and ct.Day() is not the right approaches. What if today is "2019-01-01",and you start time is "2018-12-23"?

The right way to compare two time.Time is https://golang.org/pkg/time/#Time.After

func (t Time) After(u Time) bool
func (t Time) Before(u Time) bool

After reports whether the time instant t is after u. Before reports whether the time instant t is before u.

So @Alex Pliutau's solution is more in common use. But need more careful with today.

package main

import (
    "fmt"
    "time"
)

func main() {
    t, _ := time.Parse(time.RFC3339, "2009-11-02T12:25:10.8584224+02:00")

    // truncate to 0:0:0
    t = t.Truncate(24 * time.Hour)
    fmt.Println("start time is:", t)

    // Current date truncate to 0:0:0
    ct := time.Now().Truncate(24 * time.Hour)
    fmt.Println("now is:", ct)
    fmt.Println("---------------")

    // for t.Before(ct) {  //if you don't want to print the date of today
    for !t.After(ct) {
        // Print all days between start date and current date
        fmt.Println(t.Format("2006-01-02 15:04:05"))
        t = t.AddDate(0, 0, 1)
    }
}

Output:

start time is: 2009-11-02 02:00:00 +0200 +0200
now is: 2009-11-10 00:00:00 +0000 UTC
---------------
2009-11-02 02:00:00
2009-11-03 02:00:00
2009-11-04 02:00:00
2009-11-05 02:00:00
2009-11-06 02:00:00
2009-11-07 02:00:00
2009-11-08 02:00:00
2009-11-09 02:00:00
2009-11-10 02:00:00

https://play.golang.org/p/iMr7M5W9K4N

答

get the loop condition right and..

package main

import (
    "fmt"
    "time"
)

func main() {
    fmt.Println("Hello, playground")
    t, _ := time.Parse(time.RFC3339, "2018-07-19T12:25:10.8584224+02:00")

    // Current date
    ct := time.Now()

    for d := t; d.Day() >= ct.Day(); d = d.AddDate(0, 0, 1) {
        // Print all days between start date and current date
        fmt.Println(d)
    }
}

Hello, playground
2018-07-19 12:25:10.8584224 +0200 +0200
2018-07-20 12:25:10.8584224 +0200 +0200
2018-07-21 12:25:10.8584224 +0200 +0200
2018-07-22 12:25:10.8584224 +0200 +0200
2018-07-23 12:25:10.8584224 +0200 +0200
2018-07-24 12:25:10.8584224 +0200 +0200
2018-07-25 12:25:10.8584224 +0200 +0200
2018-07-26 12:25:10.8584224 +0200 +0200
2018-07-27 12:25:10.8584224 +0200 +0200
2018-07-28 12:25:10.8584224 +0200 +0200
2018-07-29 12:25:10.8584224 +0200 +0200
2018-07-30 12:25:10.8584224 +0200 +0200
2018-07-31 12:25:10.8584224 +0200 +0200

https://play.golang.org/p/yRBTUZKfseG

答

Based on your comments, you need to actually tell it to Format the date to something of value:

package main

import (
    "fmt"
    "log"
    "time"
)

func main() {
    start, err := time.Parse("2006-1-2", "2018-1-1")
    if err != nil {
        log.Fatal(err)
    }

    for d := start; d.Month() == start.Month(); d = d.AddDate(0, 0, 1) {
        fmt.Println(d.Format("2006-1-2"))
    }
}

Here's a simpler version of your code (I used a custom time format, cause I didn't wanna edit the RFC syntax, but ultimately it's the same thing) = I'm also iterating Month for brevity.

答

package main

import (
    "fmt"
    "time"
)

func main() {
    t, _ := time.Parse(time.RFC3339, "2018-07-19T12:25:10.8584224+02:00")

    ct := time.Now()

    for t.Before(ct) {
        fmt.Println(t)
        t.AddDate(0, 0, 1)
    }
}

在time.Now（）到达时进行循环

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