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Programming can not be separated from time, time management, strictly speaking divided into two pieces, one is the current moment, corresponding to a point, there is a period of time interval, this article simply talk about the time-related programming of go, relatively simple.

Golang support for time is what the package does, and there are a lot of functions in it.

Familiarity with Linux under C programming is the return value of the time function:

#include

time_t now = time (NULL);

One of the most important representations in Golang is time, which is basically three member variables sec, nsec,location, and the detailed meaning can be noted in the comments.

Type Time struct {

SEC gives the number of seconds elapsed since

January 1, Year 1 00:00:00 UTC.

SEC Int64

NSEC Specifies a non-negative nanosecond

Offset within the second named by Seconds.

It must is in the range [0, 999999999].

nsec int32

LOC Specifies the location that should is used to

Determine the minute, hour, month, day, and year

That correspond to this time.

Only the zero time have a nil location.

In this case it's interpreted to mean UTC.

Loc *location

}

OK, how to access the Unix epoch time.

Now: = time. Now ()

The now () function is very important to get the current time information by using the Today () function in the Times package, which is the starting point for all subsequent conversions. From now () we get to time, from the type we take calmly to the Unix epoch time, which naturally gets to year, month, Day,weekday, Hour,minute,second,nanosecond.

Get the Unix epoch time:

var epoch_seconds int64 = Now. Unix ()

Get year

Func (T time) year () int

Cur_year: = Now. Year ()

Get month

Func (t time) month () month

Cur_month: = Now. Month ()

if Cur_month = = time. November {

...

}

Month is the int type, FMT. Printf ("%v") or FMT. Println can print out the November, and the month type has a string () function, which outputs "November" such as strings

Const (

January Month = 1 + Iota

February

March

April

May

June

July

August

September

October

November

December

)

Year Mon day, which can all be returned in the DATE function:

Func (t time) Date () (year int, month month, day int)

Year,mon,day = Now. Date ()

Get Hour

Func (t time) Hour () int

Cur_hour: = Now. Hour ()

Minute can be returned by minute (), second can be returned by second ().

Time also provides the simultaneous return of clock () Hour,minute,second = Now. Clock ().

The version of Golang is:

Package Main

Import "FMT"

Import "Time"

Func Main () {

Now: = time. Now ()

Year,mon,day: = Now. UTC (). Date ()

Hour,min,sec: = Now. UTC (). Clock ()

Zone,_: = Now. UTC (). Zone ()

Fmt. Printf ("UTC time is%d-%d-%d%02d:%02d:%02d%s\n",

Year,mon,day,hour,min,sec,zone)

Year,mon,day = Now. Date ()

Hour,min,sec = Now. Clock ()

Zone,_ = Now. Zone ()

Fmt. Printf ("local time is%d-%d-%d%02d:%02d:%02d%s\n",

Year,mon,day,hour,min,sec,zone)

}

Go version of output

---------------------

UTC time is 2013-11-22 15:51:22 UTC

local time is 2013-11-22 23:51:22 CST

--------------------------------------------------------------------------------------------------------------- ----------------------------------------------

Another topic of concern to us is the time interval, for example, we profile a very time-consuming function, we will write down the time value before the function starts, after the function is finished, record the time value again, and then the difference between the two is the function run time.

This shows that time can be subtracted,

Start_time: = time. Now ()

Expensive_function

End_time: =time. Now ()

var duration duration = End_time. Sub (start_time)

Duration is a data type that is actually a int64 type, characterizing the number of nanoseconds between two moments.

Type Duration Int64

Const (

nanosecond Duration = 1

microsecond = + * nanosecond

Millisecond = + * microsecond

Second = + * Millisecond

Minute = * Second

Hour = * Minute

)

The duration type has minutes ()/second ()/nanoseconds (), which translates duration into minutes per second/nanosecond.

Now: = time. Now ()

Time. Sleep (3*time. Second);

End_time: = time. Now ()

var dur_time time. Duration = End_time. Sub (now)

var elapsed_min float64 = Dur_time. Minutes ()

var elapsed_sec float64 = Dur_time. Seconds ()

var Elapsed_nano int64 = Dur_time. Nanoseconds ()

Fmt. Printf ("elasped%f minutes or \nelapsed%f seconds or \nelapsed%d nanoseconds\n",

Elapsed_min,elapsed_sec,elapsed_nano)

The output is as follows:

elasped 0.050005 minutes or

Elapsed 3.000292 seconds or

Elapsed 3000292435 nanoseconds

--------------------------------------------------------------------------------------------------------------- ---------------------------------

The second section describes duration's apparent use of the sleep () function, which is in nanoseconds, equivalent to the Nanosleep () in C language.

#include

Nanosleep (): _posix_c_source >= 199309L

int nanosleep (const struct TIMESPEC *req, struct timespec *rem);

#include

unsigned int sleep (unsigned int seconds);

The time.sleep in Go are in nanoseconds, of course the duration type:

If you need to write in sleep for 3 seconds:

Time. Sleep (3000000000)

This is too inconvenient, so, Golang can write

Time. Sleep (3*time. Second);

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