问题
I am trying to format milliseconds to formatted string preserving the milliseconds part. Here's my code:
import time
time.strftime('%Y-%m-%d %H:%M:%S:%f', time.gmtime(1515694048121/1000.0))
where 1515694048121 is a time in milliseconds. It returns me:
2018-01-11 18:07:28:f
As we can see, the millisecond portion of time is not returned.
What is correct format to include millisecond portion of time? Is '%Y-%m-%d %H:%M:%S:%f' not correct ?
回答1:
There is the no directive mentioned in time.strftime(...) that will return you the milliseconds. Not sure from where you got the reference to use %f. In fact time.gmtime(...) holds the precision only upto seconds.
As a hack, in order to achieve this, you may explicitly format your string by preserving your milli second value as:
>>> import time
>>> time_in_ms = 1515694048121
>>> time.strftime('%Y-%m-%d %H:%M:%S:{}'.format(time_in_ms%1000), time.gmtime(time_in_ms/1000.0))
'2018-01-11 18:07:28:121'
Here's the list of valid directives:
+-----------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------+
| Directive | Meaning | Notes |
+-----------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------+
| %a | Locale’s abbreviated weekday name. | |
| %A | Locale’s full weekday name. | |
| %b | Locale’s abbreviated month name. | |
| %B | Locale’s full month name. | |
| %c | Locale’s appropriate date and time representation. | |
| %d | Day of the month as a decimal number [01,31]. | |
| %H | Hour (24-hour clock) as a decimal number [00,23]. | |
| %I | Hour (12-hour clock) as a decimal number [01,12]. | |
| %j | Day of the year as a decimal number [001,366]. | |
| %m | Month as a decimal number [01,12]. | |
| %M | Minute as a decimal number [00,59]. | |
| %p | Locale’s equivalent of either AM or PM. | (1) |
| %S | Second as a decimal number [00,61]. | (2) |
| %U | Week number of the year (Sunday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Sunday are considered to be in week 0. | (3) |
| %w | Weekday as a decimal number [0(Sunday),6]. | |
| %W | Week number of the year (Monday as the first day of the week) as a decimal number [00,53]. All days in a new year preceding the first Monday are considered to be in week 0. | (3) |
| %x | Locale’s appropriate date representation. | |
| %X | Locale’s appropriate time representation. | |
| %y | Year without century as a decimal number [00,99]. | |
| %Y | Year with century as a decimal number. | |
| %z | Time zone offset indicating a positive or negative time difference from UTC/GMT of the form +HHMM or -HHMM, where H represents decimal hour digits and M represents decimal minute digits [-23:59, +23:59]. | |
| %Z | Time zone name (no characters if no time zone exists). | |
| %% | | |
+-----------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------+
回答2:
In fact time.gmtime gets a number of seconds as input parameter. As a consequence, the milliseconds are not taken into account:
>>> import time
>>> time.gmtime(1515694048121/1000.0) == time.gmtime(1515694048000/1000.0)
True
The function documentation clearly mentions it:
Fractions of a second are ignored.
来源：https://stackoverflow.com/questions/48215948/python-display-milliseconds-in-formatted-string-using-time-strftime