1 import time
  2
  3 # 2种表示时间的方法：
  4 # (1)时间戳，从1970.1.1开始
  5 # (2)一个9个整数的元组
  6 #    这个元组内容：
  7 #       year (including century, e.g. 1998)
  8 #       month (1-12)
  9 #       day (1-31)
 10 #       hours (0-23)
 11 #       minutes (0-59)
 12 #       seconds (0-59)
 13 #       weekday (0-6, Monday is 0)
 14 #       Julian day (day in the year, 1-366)
 15 #       DST (Daylight Savings Time) flag (-1, 0 or 1)
 16 #          1 if summer time is in effect, 0 if not, and -1 if unknown
 17
 18
 19 # FUNCTIONS
 20 """
 21     time(...)
 22         time() -> floating point number
 23
 24         Return the current time in seconds since the Epoch.
 25         Fractions of a second may be present if the system clock provides them.
 26         本地的当前时间的时间戳
 27 """
 28 print(time.time())
 29
 30 """
 31     localtime(...)
 32         localtime([seconds]) -> (tm_year,tm_mon,tm_mday,tm_hour,tm_min,
 33                                   tm_sec,tm_wday,tm_yday,tm_isdst)
 34
 35         Convert seconds since the Epoch to a time tuple expressing local time.
 36         When 'seconds' is not passed in, convert the current time instead.
 37         没有参数时本地的当前时间的元组形式
 38 """
 39 print(time.localtime())
 40
 41 """
 42     gmtime(...)
 43         gmtime([seconds]) -> (tm_year, tm_mon, tm_mday, tm_hour, tm_min,
 44                                tm_sec, tm_wday, tm_yday, tm_isdst)
 45
 46         Convert seconds since the Epoch to a time tuple expressing UTC (a.k.a.
 47         GMT).  When 'seconds' is not passed in, convert the current time instead.
 48
 49         If the platform supports the tm_gmtoff and tm_zone, they are available as
 50         attributes only.
 51 """
 52 print(time.gmtime(time.time()))
 53
 54
 55 """
 56     mktime(...)
 57         mktime(tuple) -> floating point number
 58
 59         Convert a time tuple in local time to seconds since the Epoch.
 60         Note that mktime(gmtime(0)) will not generally return zero for most
 61         time zones; instead the returned value will either be equal to that
 62         of the timezone or altzone attributes on the time module.
 63 """
 64 print(time.mktime(time.localtime()))
 65
 66
 67 """
 68     asctime(...)
 69         asctime([tuple]) -> string
 70
 71         Convert a time tuple to a string, e.g. 'Sat Jun 06 16:26:11 1998'.
 72         When the time tuple is not present, current time as returned by localtime()
 73         is used.
 74         tuple转字符串，默认是当前时间
 75 """
 76 print(time.asctime())   # Thu Jan 18 16:36:07 2018
 77
 78 """
 79     ctime(...)
 80         ctime(seconds) -> string
 81
 82         Convert a time in seconds since the Epoch to a string in local time.
 83         This is equivalent to asctime(localtime(seconds)). When the time tuple is
 84         not present, current time as returned by localtime() is used.
 85         时间戳转字符串，默认是当前时间
 86 """
 87 print(time.ctime())
 88
 89 """
 90     strftime(...)
 91         strftime(format[, tuple]) -> string
 92
 93         Convert a time tuple to a string according to a format specification.
 94         See the library reference manual for formatting codes. When the time tuple
 95         is not present, current time as returned by localtime() is used.
 96
 97         Commonly used format codes:
 98
 99         %Y  Year with century as a decimal number.
100         %m  Month as a decimal number [01,12].
101         %d  Day of the month as a decimal number [01,31].
102         %H  Hour (24-hour clock) as a decimal number [00,23].
103         %M  Minute as a decimal number [00,59].
104         %S  Second as a decimal number [00,61].
105         %z  Time zone offset from UTC.      +0800
106         %a  Locale's abbreviated weekday name.      Thu
107         %A  Locale's full weekday name.      Thursday
108         %b  Locale's abbreviated month name.     Jan
109         %B  Locale's full month name.     January
110         %c  Locale's appropriate date and time representation. Thu Jan 18 16:53:35 2018
111         %I  Hour (12-hour clock) as a decimal number [01,12].  04
112         %p  Locale's equivalent of either AM or PM.            PM
113
114         Other codes may be available on your platform.  See documentation for
115         the C library strftime function.
116         格式化元组到字符串
117 """
118 print(time.strftime('%Y-%m-%d %H:%M:%S', time.localtime()))
119
120 """
121     strptime(...)
122         strptime(string, format) -> struct_time
123
124         Parse a string to a time tuple according to a format specification.
125         See the library reference manual for formatting codes (same as
126         strftime()).
127
128         Commonly used format codes:
129
130         %Y  Year with century as a decimal number.
131         %m  Month as a decimal number [01,12].
132         %d  Day of the month as a decimal number [01,31].
133         %H  Hour (24-hour clock) as a decimal number [00,23].
134         %M  Minute as a decimal number [00,59].
135         %S  Second as a decimal number [00,61].
136         %z  Time zone offset from UTC.
137         %a  Locale's abbreviated weekday name.
138         %A  Locale's full weekday name.
139         %b  Locale's abbreviated month name.
140         %B  Locale's full month name.
141         %c  Locale's appropriate date and time representation.
142         %I  Hour (12-hour clock) as a decimal number [01,12].
143         %p  Locale's equivalent of either AM or PM.
144
145         Other codes may be available on your platform.  See documentation for
146         the C library strftime function.
147         字符串到元组
148 """
149 #
150 print(time.strptime('2018-01-18 16:55:01', '%Y-%m-%d %H:%M:%S'))
151 print(time.strptime('Thu Jan 18 16:55:56 2018', '%c'))
152
153 """
154     sleep(...)
155         sleep(seconds)
156
157         Delay execution for a given number of seconds.  The argument may be
158         a floating point number for subsecond precision.
159 """
160 """
161     clock(...)
162         clock() -> floating point number
163
164         Return the CPU time or real time since the start of the process or since
165         the first call to clock().  This has as much precision as the system
166         records.
167 """
168 def func():
169     sum = 0
170     for i in range(1000):
171         sum = sum + 1
172         time.sleep(0.01)
173
174 t0 = time.clock()
175 p0 = time.time()
176 print(t0, p0)
177 func()
178 t1 = time.clock()
179 p1 = time.time()
180 print(t1, p1)
181 print(t1-t0, p1-p0)   # 0.08869099999999999 10.986821174621582
182 # linux端，clock只统计cpu运行的时间，执行语句，sleep不统计。windows不一样
183
184 """
185     get_clock_info(...)
186         get_clock_info(name: str) -> dict
187
188         Get information of the specified clock.
189 """
190 print(time.get_clock_info('clock'))
191 print(time.get_clock_info('monotonic'))
192 print(time.get_clock_info('perf_counter'))
193 print(time.get_clock_info('process_time'))
194 print(time.get_clock_info('time'))
195
196
197 """
198     monotonic(...)
199         monotonic() -> float
200
201         Monotonic clock, cannot go backward.
202         系统启动，开启的一个时钟，也就是系统开启时间
203 """
204
205
206 """
207     perf_counter(...)
208         perf_counter() -> float
209
210         Performance counter for benchmarking.
211         系统运行时间
212 """
213
214
215 """
216     process_time(...)
217         process_time() -> float
218
219         Process time for profiling: sum of the kernel and user-space CPU time.
220 """
221 def func():
222     sum = 0
223     for i in range(1000):
224         sum = sum + 1
225         time.sleep(0.01)
226
227 t0 = time.process_time()
228 p0 = time.time()
229 print(t0, p0)
230 func()
231 t1 = time.process_time()
232 p1 = time.time()
233 print(t1, p1)
234 print(t1-t0, p1-p0)   # 0.08869099999999999 10.986821174621582
235 # 统计内核和用户空间占用cpu的时间