lancet/docs/datetime.md

# Datetime
Package datetime supports date and time format and compare.

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## Source:

[https://github.com/duke-git/lancet/blob/main/datetime/datetime.go](https://github.com/duke-git/lancet/blob/main/datetime/datetime.go)

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## Usage:
```go
import (
    "github.com/duke-git/lancet/datetime"
)
```

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## Index
- [AddDay](#AddDay)
- [AddHour](#AddHour)
- [AddMinute](#AddMinute)
- [GetNowDate](#GetNowDate)
- [GetNowTime](#GetNowTime)
- [GetNowDateTime](#GetNowDateTime)
- [GetZeroHourTimestamp](#GetZeroHourTimestamp)
- [GetNightTimestamp](#GetNightTimestamp)
- [FormatTimeToStr](#FormatTimeToStr)

- [FormatStrToTime](#FormatStrToTime)

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## Documentation

## Note:
1. 'format' string param in func FormatTimeToStr and FormatStrToTime function should be one of flows:
- yyyy-mm-dd hh:mm:ss
- yyyy-mm-dd hh:mm
- yyyy-mm-dd hh
- yyyy-mm-dd
- yyyy-mm
- mm-dd
- dd-mm-yy hh:mm:ss
- yyyy/mm/dd hh:mm:ss
- yyyy/mm/dd hh:mm
- yyyy-mm-dd hh
- yyyy/mm/dd
- yyyy/mm
- mm/dd
- dd/mm/yy hh:mm:ss
- yyyy
- mm
- hh:mm:ss
- mm:ss


### <span id="AddDay">AddDay</span>
<p>Add or sub days to time.</p>

<b>Signature:</b>

```go
func AddDay(t time.Time, day int64) time.Time
```
<b>Example:</b>

```go
package main

import (
    "fmt"
    "time"
    "github.com/duke-git/lancet/datetime"
)

func main() {
    now := time.Now()
    after2Days := datetime.AddDay(now, 2)
    before2Days := datetime.AddDay(now, -2)

    fmt.Println(after2Days, before2Days)
}
```


### <span id="AddHour">AddHour</span>
<p>Add or sub hours to time.</p>

<b>Signature:</b>

```go
func AddHour(t time.Time, hour int64) time.Time
```
<b>Example:</b>

```go
package main

import (
    "fmt"
    "time"
    "github.com/duke-git/lancet/datetime"
)

func main() {
    now := time.Now()
    after2Hours := datetime.AddHour(now, 2)
    before2Hours := datetime.AddHour(now, -2)

    fmt.Println(after2Hours, after2Hours)
}
```

### <span id="AddMinute">AddMinute</span>
<p>Add or sub minutes to time.</p>

<b>Signature:</b>

```go
func AddMinute(t time.Time, minute int64) time.Time
```
<b>Example:</b>

```go
package main

import (
    "fmt"
    "time"
    "github.com/duke-git/lancet/datetime"
)

func main() {
    now := time.Now()
    after2Minute := datetime.AddMinute(now, 2)
    before2Minute := datetime.AddMinute(now, -2)

    fmt.Println(after2Minute, before2Minute)
}
```

### <span id="GetNowDate">GetNowDate</span>
<p>Get current date string, format is yyyy-mm-dd.</p>

<b>Signature:</b>

```go
func GetNowDate() string
```
<b>Example:</b>

```go
package main

import (
    "fmt"
    "time"
    "github.com/duke-git/lancet/datetime"
)

func main() {
    now := time.Now()
    currentDate := datetime.GetNowDate()
    fmt.Println(currentDate) // 2022-01-28
}
```


### <span id="GetNowTime">GetNowTime</span>
<p>Get current time string, format is hh:mm:ss.</p>

<b>Signature:</b>

```go
func GetNowTime() string
```
<b>Example:</b>

```go
package main

import (
    "fmt"
    "time"
    "github.com/duke-git/lancet/datetime"
)

func main() {
    now := time.Now()
    currentTime := datetime.GetNowTime()
    fmt.Println(currentDate) // 15:57:33
}
```


### <span id="GetNowDateTime">GetNowDateTime</span>
<p>Get current date time string, format is yyyy-mm-dd hh:mm:ss.</p>

<b>Signature:</b>

```go
func GetNowDateTime() string
```
<b>Example:</b>

```go
package main

import (
    "fmt"
    "time"
    "github.com/duke-git/lancet/datetime"
)

func main() {
    now := time.Now()
    current := datetime.GetNowDateTime()
    fmt.Println(current) // 2022-01-28 15:59:33
}
```


### <span id="GetZeroHourTimestamp">GetZeroHourTimestamp</span>
<p>Return timestamp of zero hour (timestamp of 00:00).</p>

<b>Signature:</b>

```go
func GetZeroHourTimestamp() int64
```
<b>Example:</b>

```go
package main

import (
    "fmt"
    "time"
    "github.com/duke-git/lancet/datetime"
)

func main() {
    now := time.Now()
    zeroTime := datetime.GetZeroHourTimestamp()
    fmt.Println(zeroTime) // 1643299200
}
```


### <span id="GetNightTimestamp">GetNightTimestamp</span>
<p>Return timestamp of zero hour (timestamp of 23:59).</p>

<b>Signature:</b>

```go
func GetNightTimestamp() int64
```
<b>Example:</b>

```go
package main

import (
    "fmt"
    "time"
    "github.com/duke-git/lancet/datetime"
)

func main() {
    now := time.Now()
    nightTime := datetime.GetNightTimestamp()
    fmt.Println(nightTime) // 1643385599
}
```

### <span id="FormatTimeToStr">FormatTimeToStr</span>
<p>Format time to string, `format` param specification see note 1.</p>

<b>Signature:</b>

```go
func FormatTimeToStr(t time.Time, format string) string
```
<b>Example:</b>

```go
package main

import (
    "fmt"
    "time"
    "github.com/duke-git/lancet/datetime"
)

func main() {
    now := time.Now()
    timeStr := datetime.FormatTimeToStr(now, "yyyy/mm/dd hh:mm:ss")
    fmt.Println(timeStr) //2022/01/28 16:07:44
}
```


### <span id="FormatStrToTime">FormatStrToTime</span>
<p>Format string to time, `format` param specification see note 1.</p>

<b>Signature:</b>

```go
func FormatStrToTime(str, format string) (time.Time, error)
```
<b>Example:</b>

```go
package main

import (
    "fmt"
    "github.com/duke-git/lancet/datetime"
)

func main() {
    time := datetime.FormatStrToTime("2006-01-02 15:04:05", "yyyy/mm/dd hh:mm:ss")
    fmt.Println(time)
}
```