python之time模块

 

在我们学习的过程中,肯定会用到各种各样的模块。所以今天我们从time模块开始学习

首先我们在使用某个模块的时候,肯定要先导入这个模块

import time 

 而当我们想看看这个模块是干什么的,我们可以使用help函数来看

print(help(time)) # 打印帮助信息

python之time模块

  1 "E:\Program Files (x86)\python_3.8\python.exe" D:/Application/pycharm_works/_1/test/python模块之time模块.py
  2 Help on built-in module time:
  3 
  4 NAME
  5     time - This module provides various functions to manipulate time values.
  6 
  7 DESCRIPTION
  8     There are two standard representations of time.  One is the number
  9     of seconds since the Epoch, in UTC (a.k.a. GMT).  It may be an integer
 10     or a floating point number (to represent fractions of seconds).
 11     The Epoch is system-defined; on Unix, it is generally January 1st, 1970.
 12     The actual value can be retrieved by calling gmtime(0).
 13     
 14     The other representation is a tuple of 9 integers giving local time.
 15     The tuple items are:
 16       year (including century, e.g. 1998)
 17       month (1-12)
 18       day (1-31)
 19       hours (0-23)
 20       minutes (0-59)
 21       seconds (0-59)
 22       weekday (0-6, Monday is 0)
 23       Julian day (day in the year, 1-366)
 24       DST (Daylight Savings Time) flag (-1, 0 or 1)
 25     If the DST flag is 0, the time is given in the regular time zone;
 26     if it is 1, the time is given in the DST time zone;
 27     if it is -1, mktime() should guess based on the date and time.
 28 
 29 CLASSES
 30     builtins.tuple(builtins.object)
 31         struct_time
 32     
 33     class struct_time(builtins.tuple)
 34      |  struct_time(iterable=(), /)
 35      |  
 36      |  The time value as returned by gmtime(), localtime(), and strptime(), and
 37      |  accepted by asctime(), mktime() and strftime().  May be considered as a
 38      |  sequence of 9 integers.
 39      |  
 40      |  Note that several fields' values are not the same as those defined by
 41      |  the C language standard for struct tm.  For example, the value of the
 42      |  field tm_year is the actual year, not year - 1900.  See individual
 43      |  fields' descriptions for details.
 44      |  
 45      |  Method resolution order:
 46      |      struct_time
 47      |      builtins.tuple
 48      |      builtins.object
 49      |  
 50      |  Methods defined here:
 51      |  
 52      |  __reduce__(...)
 53      |      Helper for pickle.
 54      |  
 55      |  __repr__(self, /)
 56      |      Return repr(self).
 57      |  
 58      |  ----------------------------------------------------------------------
 59      |  Static methods defined here:
 60      |  
 61      |  __new__(*args, **kwargs) from builtins.type
 62      |      Create and return a new object.  See help(type) for accurate signature.
 63      |  
 64      |  ----------------------------------------------------------------------
 65      |  Data descriptors defined here:
 66      |  
 67      |  tm_gmtoff
 68      |      offset from UTC in seconds
 69      |  
 70      |  tm_hour
 71      |      hours, range [0, 23]
 72      |  
 73      |  tm_isdst
 74      |      1 if summer time is in effect, 0 if not, and -1 if unknown
 75      |  
 76      |  tm_mday
 77      |      day of month, range [1, 31]
 78      |  
 79      |  tm_min
 80      |      minutes, range [0, 59]
 81      |  
 82      |  tm_mon
 83      |      month of year, range [1, 12]
 84      |  
 85      |  tm_sec
 86      |      seconds, range [0, 61])
 87      |  
 88      |  tm_wday
 89      |      day of week, range [0, 6], Monday is 0
 90      |  
 91      |  tm_yday
 92      |      day of year, range [1, 366]
 93      |  
 94      |  tm_year
 95      |      year, for example, 1993
 96      |  
 97      |  tm_zone
 98      |      abbreviation of timezone name
 99      |  
100      |  ----------------------------------------------------------------------
101      |  Data and other attributes defined here:
102      |  
103      |  n_fields = 11
104      |  
105      |  n_sequence_fields = 9
106      |  
107      |  n_unnamed_fields = 0
108      |  
109      |  ----------------------------------------------------------------------
110      |  Methods inherited from builtins.tuple:
111      |  
112      |  __add__(self, value, /)
113      |      Return self+value.
114      |  
115      |  __contains__(self, key, /)
116      |      Return key in self.
117      |  
118      |  __eq__(self, value, /)
119      |      Return self==value.
120      |  
121      |  __ge__(self, value, /)
122      |      Return self>=value.
123      |  
124      |  __getattribute__(self, name, /)
125      |      Return getattr(self, name).
126      |  
127      |  __getitem__(self, key, /)
128      |      Return self[key].
129      |  
130      |  __getnewargs__(self, /)
131      |  
132      |  __gt__(self, value, /)
133      |      Return self>value.
134      |  
135      |  __hash__(self, /)
136      |      Return hash(self).
137      |  
138      |  __iter__(self, /)
139      |      Implement iter(self).
140      |  
141      |  __le__(self, value, /)
142      |      Return self<=value.
143      |  
144      |  __len__(self, /)
145      |      Return len(self).
146      |  
147      |  __lt__(self, value, /)
148      |      Return self<value.
149      |  
150      |  __mul__(self, value, /)
151      |      Return self*value.
152      |  
153      |  __ne__(self, value, /)
154      |      Return self!=value.
155      |  
156      |  __rmul__(self, value, /)
157      |      Return value*self.
158      |  
159      |  count(self, value, /)
160      |      Return number of occurrences of value.
161      |  
162      |  index(self, value, start=0, stop=9223372036854775807, /)
163      |      Return first index of value.
164      |      
165      |      Raises ValueError if the value is not present.
166 
167 FUNCTIONS
168     asctime(...)
169         asctime([tuple]) -> string
170         
171         Convert a time tuple to a string, e.g. 'Sat Jun 06 16:26:11 1998'.
172         When the time tuple is not present, current time as returned by localtime()
173         is used.
174     
175     ctime(...)
176         ctime(seconds) -> string
177         
178         Convert a time in seconds since the Epoch to a string in local time.
179         This is equivalent to asctime(localtime(seconds)). When the time tuple is
180         not present, current time as returned by localtime() is used.
181     
182     get_clock_info(...)
183         get_clock_info(name: str) -> dict
184         
185         Get information of the specified clock.
186     
187     gmtime(...)
188         gmtime([seconds]) -> (tm_year, tm_mon, tm_mday, tm_hour, tm_min,
189                                tm_sec, tm_wday, tm_yday, tm_isdst)
190         
191         Convert seconds since the Epoch to a time tuple expressing UTC (a.k.a.
192         GMT).  When 'seconds' is not passed in, convert the current time instead.
193         
194         If the platform supports the tm_gmtoff and tm_zone, they are available as
195         attributes only.
196     
197     localtime(...)
198         localtime([seconds]) -> (tm_year,tm_mon,tm_mday,tm_hour,tm_min,
199                                   tm_sec,tm_wday,tm_yday,tm_isdst)
200         
201         Convert seconds since the Epoch to a time tuple expressing local time.
202         When 'seconds' is not passed in, convert the current time instead.
203     
204     mktime(...)
205         mktime(tuple) -> floating point number
206         
207         Convert a time tuple in local time to seconds since the Epoch.
208         Note that mktime(gmtime(0)) will not generally return zero for most
209         time zones; instead the returned value will either be equal to that
210         of the timezone or altzone attributes on the time module.
211     
212     monotonic(...)
213         monotonic() -> float
214         
215         Monotonic clock, cannot go backward.
216     
217     monotonic_ns(...)
218         monotonic_ns() -> int
219         
220         Monotonic clock, cannot go backward, as nanoseconds.
221     
222     perf_counter(...)
223         perf_counter() -> float
224         
225         Performance counter for benchmarking.
226     
227     perf_counter_ns(...)
228         perf_counter_ns() -> int
229         
230         Performance counter for benchmarking as nanoseconds.
231     
232     process_time(...)
233         process_time() -> float
234         
235         Process time for profiling: sum of the kernel and user-space CPU time.
236     
237     process_time_ns(...)
238         process_time() -> int
239         
240         Process time for profiling as nanoseconds:
241         sum of the kernel and user-space CPU time.
242     
243     sleep(...)
244         sleep(seconds)
245         
246         Delay execution for a given number of seconds.  The argument may be
247         a floating point number for subsecond precision.
248     
249     strftime(...)
250         strftime(format[, tuple]) -> string
251         
252         Convert a time tuple to a string according to a format specification.
253         See the library reference manual for formatting codes. When the time tuple
254         is not present, current time as returned by localtime() is used.
255         
256         Commonly used format codes:
257         
258         %Y  Year with century as a decimal number.
259         %m  Month as a decimal number [01,12].
260         %d  Day of the month as a decimal number [01,31].
261         %H  Hour (24-hour clock) as a decimal number [00,23].
262         %M  Minute as a decimal number [00,59].
263         %S  Second as a decimal number [00,61].
264         %z  Time zone offset from UTC.
265         %a  Locale's abbreviated weekday name.
266         %A  Locale's full weekday name.
267         %b  Locale's abbreviated month name.
268         %B  Locale's full month name.
269         %c  Locale's appropriate date and time representation.
270         %I  Hour (12-hour clock) as a decimal number [01,12].
271         %p  Locale's equivalent of either AM or PM.
272         
273         Other codes may be available on your platform.  See documentation for
274         the C library strftime function.
275     
276     strptime(...)
277         strptime(string, format) -> struct_time
278         
279         Parse a string to a time tuple according to a format specification.
280         See the library reference manual for formatting codes (same as
281         strftime()).
282         
283         Commonly used format codes:
284         
285         %Y  Year with century as a decimal number.
286         %m  Month as a decimal number [01,12].
287         %d  Day of the month as a decimal number [01,31].
288         %H  Hour (24-hour clock) as a decimal number [00,23].
289         %M  Minute as a decimal number [00,59].
290         %S  Second as a decimal number [00,61].
291         %z  Time zone offset from UTC.
292         %a  Locale's abbreviated weekday name.
293         %A  Locale's full weekday name.
294         %b  Locale's abbreviated month name.
295         %B  Locale's full month name.
296         %c  Locale's appropriate date and time representation.
297         %I  Hour (12-hour clock) as a decimal number [01,12].
298         %p  Locale's equivalent of either AM or PM.
299         
300         Other codes may be available on your platform.  See documentation for
301         the C library strftime function.
302     
303     thread_time(...)
304         thread_time() -> float
305         
306         Thread time for profiling: sum of the kernel and user-space CPU time.
307     
308     thread_time_ns(...)
309         thread_time() -> int
310         
311         Thread time for profiling as nanoseconds:
312         sum of the kernel and user-space CPU time.
313     
314     time(...)
315         time() -> floating point number
316         
317         Return the current time in seconds since the Epoch.
318         Fractions of a second may be present if the system clock provides them.
319     
320     time_ns(...)
321         time_ns() -> int
322         
323         Return the current time in nanoseconds since the Epoch.
324 
325 DATA
326     altzone = -32400
327     daylight = 0
328     timezone = -28800
329     tzname = ('中国标准时间', '中国夏令时')
330 
331 FILE
332     (built-in)
333 
334 
335 None
336 
337 Process finished with exit code 0

View Code

 那么接下来我们挨个来看看

1. time.time()当前时间戳,从1900年开始到当前时间的秒数

print(help(time.time)) # 打印帮助信息
print(time.time()) #1610720236.653394 # 打印当前时间戳

python之time模块

 1 Help on built-in function time in module time:
 2 
 3 time(...)
 4     time() -> floating point number
 5     
 6     Return the current time in seconds since the Epoch.
 7     Fractions of a second may be present if the system clock provides them.
 8 
 9 None
10 1610727247.1696546

View Code

2. time.sleep(secs) 让程序暂停secs

1 print(help(time.sleep)) # 打印帮助信息
2 time.sleep(3) # 暂停3秒

python之time模块

1 Help on built-in function sleep in module time:
2 
3 sleep(...)
4     sleep(seconds)
5     
6     Delay execution for a given number of seconds.  The argument may be
7     a floating point number for subsecond precision.
8 
9 None

View Code

 

3.time.gmtime() 结构化时间,不过要注意的一点是这个时间是世界标准时间(格林尼治时间)

1 print(help(time.gmtime)) # 打印帮助信息
2 print(time.gmtime()) # 结构化时间 time.struct_time(tm_year=2021, tm_mon=1, tm_mday=15, tm_hour=14, tm_min=22, tm_sec=30, tm_wday=4, tm_yday=15, tm_isdst=0)

python之time模块

 1 Help on built-in function gmtime in module time:
 2 
 3 gmtime(...)
 4     gmtime([seconds]) -> (tm_year, tm_mon, tm_mday, tm_hour, tm_min,
 5                            tm_sec, tm_wday, tm_yday, tm_isdst)
 6     
 7     Convert seconds since the Epoch to a time tuple expressing UTC (a.k.a.
 8     GMT).  When 'seconds' is not passed in, convert the current time instead.
 9     
10     If the platform supports the tm_gmtoff and tm_zone, they are available as
11     attributes only.
12 
13 None
14 time.struct_time(tm_year=2021, tm_mon=1, tm_mday=15, tm_hour=16, tm_min=16, tm_sec=39, tm_wday=4, tm_yday=15, tm_isdst=0)

View Code

不过这时肯定有人该问了,那我们的当地时间怎么表示呢,所以我们来介绍下一个

4.time.localtime()结构化时间,当前时间

1 print(help(time.localtime)) # 打印帮助信息
2 print(time.localtime()) # 当前结构化时间

python之time模块

 1 Help on built-in function localtime in module time:
 2 
 3 localtime(...)
 4     localtime([seconds]) -> (tm_year,tm_mon,tm_mday,tm_hour,tm_min,
 5                               tm_sec,tm_wday,tm_yday,tm_isdst)
 6     
 7     Convert seconds since the Epoch to a time tuple expressing local time.
 8     When 'seconds' is not passed in, convert the current time instead.
 9 
10 None
11 time.struct_time(tm_year=2021, tm_mon=1, tm_mday=16, tm_hour=0, tm_min=17, tm_sec=49, tm_wday=5, tm_yday=16, tm_isdst=0)

View Code

 

总说结构化时间,那结构化时间是什么呢,我们来看看里面的参数

 1 我们来拿上面这个例子来解释:
 2 
 3 tm_year=2021     当前所在年
 4 tm_mon=1         当前所在月
 5 tm_mday=15       当前所在天
 6 tm_hour=23       当前所在时
 7 tm_min=18        当前所在分
 8 tm_sec=57        当前所在秒
 9 tm_wday=4        当前周的第几天
10 tm_yday=15       当前年的第几天

但是有时候我们需要的并不是结构化时间,而是类似于 2021-01-15 23:28:26 这样的格式化时间,那我们应该怎么做呢?

6. time.strftime() 将结构话时间化为格式化时间

1 print(help(time.strftime)) # 打印帮助信息
2 struct_time=time.localtime()
3 print(time.strftime("%Y-%m-%d %H:%M:%S",struct_time)) # 格式化时间

python之time模块

 1 Help on built-in function strftime in module time:
 2 
 3 strftime(...)
 4     strftime(format[, tuple]) -> string
 5     
 6     Convert a time tuple to a string according to a format specification.
 7     See the library reference manual for formatting codes. When the time tuple
 8     is not present, current time as returned by localtime() is used.
 9     
10     Commonly used format codes:
11     
12     %Y  Year with century as a decimal number.
13     %m  Month as a decimal number [01,12].
14     %d  Day of the month as a decimal number [01,31].
15     %H  Hour (24-hour clock) as a decimal number [00,23].
16     %M  Minute as a decimal number [00,59].
17     %S  Second as a decimal number [00,61].
18     %z  Time zone offset from UTC.
19     %a  Locale's abbreviated weekday name.
20     %A  Locale's full weekday name.
21     %b  Locale's abbreviated month name.
22     %B  Locale's full month name.
23     %c  Locale's appropriate date and time representation.
24     %I  Hour (12-hour clock) as a decimal number [01,12].
25     %p  Locale's equivalent of either AM or PM.
26     
27     Other codes may be available on your platform.  See documentation for
28     the C library strftime function.
29 
30 None
31 2021-01-16 00:18:38

View Code

同样这里为什么要写成 "%Y-%m-%d %H:%M:%S" 呢,就是为了控制时间的格式。

那这些都表示什么呢,我们来看看

 1     %Y  Year with century as a decimal number.
 2     %m  Month as a decimal number [01,12].
 3     %d  Day of the month as a decimal number [01,31].
 4     %H  Hour (24-hour clock) as a decimal number [00,23].
 5     %M  Minute as a decimal number [00,59].
 6     %S  Second as a decimal number [00,61].
 7     %z  Time zone offset from UTC.
 8     %a  Locale's abbreviated weekday name.
 9     %A  Locale's full weekday name.
10     %b  Locale's abbreviated month name.
11     %B  Locale's full month name.
12     %c  Locale's appropriate date and time representation.
13     %I  Hour (12-hour clock) as a decimal number [01,12].
14     %p  Locale's equivalent of either AM or PM.

不过似乎也可以单独使用   time.strftime(),我们来看看结果,但是我们必须要把格式加上,如下所示:

print(time.strftime("%Y-%m-%d %H:%M:%S")) # 格式化时间  
# 2021-01-15 23:36:49

那么,有时候我们也需要把格式化时间转化为结构化时间来使用,这时我们仅仅需要看看接下来的知识就能掌握

7. time.strptime() 将格式化时间(字符串)转化为结构化时间

print(help(time.strftime))
print
(time.strftime("%Y-%m-%d %H:%M:%S")) # 格式化时间 # 2021-01-15 23:36:49

python之time模块

 1 Help on built-in function strftime in module time:
 2 
 3 strftime(...)
 4     strftime(format[, tuple]) -> string
 5     
 6     Convert a time tuple to a string according to a format specification.
 7     See the library reference manual for formatting codes. When the time tuple
 8     is not present, current time as returned by localtime() is used.
 9     
10     Commonly used format codes:
11     
12     %Y  Year with century as a decimal number.
13     %m  Month as a decimal number [01,12].
14     %d  Day of the month as a decimal number [01,31].
15     %H  Hour (24-hour clock) as a decimal number [00,23].
16     %M  Minute as a decimal number [00,59].
17     %S  Second as a decimal number [00,61].
18     %z  Time zone offset from UTC.
19     %a  Locale's abbreviated weekday name.
20     %A  Locale's full weekday name.
21     %b  Locale's abbreviated month name.
22     %B  Locale's full month name.
23     %c  Locale's appropriate date and time representation.
24     %I  Hour (12-hour clock) as a decimal number [01,12].
25     %p  Locale's equivalent of either AM or PM.
26     
27     Other codes may be available on your platform.  See documentation for
28     the C library strftime function.
29 
30 None
31 2021-01-16 00:20:46

View Code

当然以上只是一个举例,具体我们可以采用如下方式:

a=time.strptime("2021-01-15 22:26:28","%Y-%m-%d %H:%M:%S")
print(a.tm_yday)   # 15
print(a.tm_wday)   # 4

最后,我们快接近了尾声,最后我们再介绍两个就结束了

8. time.ctime() 将所给时间戳转变为一个格式化时间

1 print(help(time.ctime))  # 将时间戳转变为一个格式化时间
2 print(time.ctime())   # 如果不带参数则默认为当前时间戳
3 print(time.ctime(12412415))

python之time模块

 1 Help on built-in function ctime in module time:
 2 
 3 ctime(...)
 4     ctime(seconds) -> string
 5     
 6     Convert a time in seconds since the Epoch to a string in local time.
 7     This is equivalent to asctime(localtime(seconds)). When the time tuple is
 8     not present, current time as returned by localtime() is used.
 9 
10 None
11 Sat Jan 16 00:21:56 2021
12 Sun May 24 23:53:35 1970

View Code

9.time.mktime()  将所给结构化时间转化为时间戳

1 print(help(time.ctime))  # 打印帮助信息
2 print(time.mktime(time.localtime())) # 将结构化时间转化为时间戳

python之time模块

 1 Help on built-in function ctime in module time:
 2 
 3 ctime(...)
 4     ctime(seconds) -> string
 5     
 6     Convert a time in seconds since the Epoch to a string in local time.
 7     This is equivalent to asctime(localtime(seconds)). When the time tuple is
 8     not present, current time as returned by localtime() is used.
 9 
10 None
11 1610727764.0

View Code

不过值得一提的是,这种方式得到的时间戳精度要比time.time()低的多

最后,在提供一种其他求当前时间的方法

import datetime

print(datetime.datetime.now())  # 2021-01-15 23:55:48.985808

本次time模块便到此结束,其他模块下次讲解

 

发表评论

评论已关闭。

相关文章