📜  Ruby-日期和时间

📅  最后修改于: 2020-10-16 05:54:02             🧑  作者: Mango


Time类表示Ruby中的日期和时间。它是操作系统提供的系统日期和时间功能的薄薄一层。此类在您的系统上可能无法表示1970年之前或2038年之后的日期。

本章使您熟悉所有最想要的日期和时间概念。

获取当前日期和时间

以下是获取当前日期和时间的简单示例-

#!/usr/bin/ruby -w

time1 = Time.new
puts "Current Time : " + time1.inspect

# Time.now is a synonym:
time2 = Time.now
puts "Current Time : " + time2.inspect

这将产生以下结果-

Current Time : Mon Jun 02 12:02:39 -0700 2008
Current Time : Mon Jun 02 12:02:39 -0700 2008

获取日期和时间的组成部分

我们可以使用Time对象来获取日期和时间的各个组成部分。以下是显示相同内容的示例-

#!/usr/bin/ruby -w

time = Time.new

# Components of a Time
puts "Current Time : " + time.inspect
puts time.year    # => Year of the date 
puts time.month   # => Month of the date (1 to 12)
puts time.day     # => Day of the date (1 to 31 )
puts time.wday    # => 0: Day of week: 0 is Sunday
puts time.yday    # => 365: Day of year
puts time.hour    # => 23: 24-hour clock
puts time.min     # => 59
puts time.sec     # => 59
puts time.usec    # => 999999: microseconds
puts time.zone    # => "UTC": timezone name

这将产生以下结果-

Current Time : Mon Jun 02 12:03:08 -0700 2008
2008
6
2
1
154
12
3
8
247476
UTC

Time.utc,Time.gm和Time.local函数

这两个功能可用于以以下标准格式格式化日期-

# July 8, 2008
Time.local(2008, 7, 8)  
# July 8, 2008, 09:10am, local time
Time.local(2008, 7, 8, 9, 10)   
# July 8, 2008, 09:10 UTC
Time.utc(2008, 7, 8, 9, 10)  
# July 8, 2008, 09:10:11 GMT (same as UTC)
Time.gm(2008, 7, 8, 9, 10, 11)  

以下是以以下格式获取数组中所有组件的示例-

[sec,min,hour,day,month,year,wday,yday,isdst,zone]

尝试以下-

#!/usr/bin/ruby -w

time = Time.new
values = time.to_a
p values

这将产生以下结果-

[26, 10, 12, 2, 6, 2008, 1, 154, false, "MST"]

该数组可以传递给Time.utcTime.local函数以获取不同的日期格式,如下所示:

#!/usr/bin/ruby -w

time = Time.new
values = time.to_a
puts Time.utc(*values)

这将产生以下结果-

Mon Jun 02 12:15:36 UTC 2008

以下是获取自(平台相关的)时代以来内部以秒表示的时间的方法-

# Returns number of seconds since epoch
time = Time.now.to_i  

# Convert number of seconds into Time object.
Time.at(time)

# Returns second since epoch which includes microseconds
time = Time.now.to_f

时区和夏时制

您可以使用Time对象来获取与时区和夏令时相关的所有信息,如下所示:

time = Time.new

# Here is the interpretation
time.zone       # => "UTC": return the timezone
time.utc_offset # => 0: UTC is 0 seconds offset from UTC
time.zone       # => "PST" (or whatever your timezone is)
time.isdst      # => false: If UTC does not have DST.
time.utc?       # => true: if t is in UTC time zone
time.localtime  # Convert to local timezone.
time.gmtime     # Convert back to UTC.
time.getlocal   # Return a new Time object in local zone
time.getutc     # Return a new Time object in UTC

格式化时间和日期

有多种格式化日期和时间的方法。这是一个显示几个例子-

#!/usr/bin/ruby -w

time = Time.new
puts time.to_s
puts time.ctime
puts time.localtime
puts time.strftime("%Y-%m-%d %H:%M:%S")

这将产生以下结果-

Mon Jun 02 12:35:19 -0700 2008
Mon Jun  2 12:35:19 2008
Mon Jun 02 12:35:19 -0700 2008
2008-06-02 12:35:19

时间格式指令

下表中的这些指令与Time.strftime方法一起使用

Sr.No. Directive & Description
1

%a

The abbreviated weekday name (Sun).

2

%A

The full weekday name (Sunday).

3

%b

The abbreviated month name (Jan).

4

%B

The full month name (January).

5

%c

The preferred local date and time representation.

6

%d

Day of the month (01 to 31).

7

%H

Hour of the day, 24-hour clock (00 to 23).

8

%I

Hour of the day, 12-hour clock (01 to 12).

9

%j

Day of the year (001 to 366).

10

%m

Month of the year (01 to 12).

11

%M

Minute of the hour (00 to 59).

12

%p

Meridian indicator (AM or PM).

13

%S

Second of the minute (00 to 60).

14

%U

Week number of the current year, starting with the first Sunday as the first day of the first week (00 to 53).

15

%W

Week number of the current year, starting with the first Monday as the first day of the first week (00 to 53).

16

%w

Day of the week (Sunday is 0, 0 to 6).

17

%x

Preferred representation for the date alone, no time.

18

%X

Preferred representation for the time alone, no date.

19

%y

Year without a century (00 to 99).

20

%Y

Year with century.

21

%Z

Time zone name.

22

%%

Literal % character.

时间算术

您可以按时间执行简单的算术,如下所示:

now = Time.now          # Current time
puts now

past = now - 10         # 10 seconds ago. Time - number => Time
puts past

future = now + 10  # 10 seconds from now Time + number => Time
puts future

diff = future - past     # => 10  Time - Time => number of seconds
puts diff

这将产生以下结果-

Thu Aug 01 20:57:05 -0700 2013
Thu Aug 01 20:56:55 -0700 2013
Thu Aug 01 20:57:15 -0700 2013
20.0