Re: Newbie question, list comprehension
Johannes Bauer [EMAIL PROTECTED] wrote:
import time
localtime = time.localtime(1234567890)
fmttime = %04d-%02d-%02d %02d:%02d:%02d % (localtime[0], localtime[1],
localtime[2], localtime[3], localtime[4], localtime[5])
print fmttime
fmttime = %04d-%02d-%02d %02d:%02d:%02d % ([localtime[i] for i in
range(0, 5)])
To reduce typing, set
format = '%04d-%02d-%02d %02d:%02d:%02d'
Two problems.
* Firstly, range(0, 5) == [0, 1, 2, 3, 4], so it's not big enough.
Python tends to do this half-open-interval thing. Once you get used
to it, you'll find that it actually reduces the number of off-by-one
errors you make.
* Secondly, the result of a list comprehension is a list;
(Unsurprising, really, I know.) But the `%' operator only extracts
multiple arguments from a tuple, so you'd need to convert:
format % tuple(localtime[i] for i in xrange(6)]
(I've replaced range by xrange, which avoids building an intermediate
list, and the first argument to range or xrange defaults to zero
anyway.)
Another poster claimed that localtime returns a tuple. This isn't
correct: it returns a time.struct_time, which is not a tuple as you can
tell:
'%s' % localtime
'(2009, 2, 13, 23, 31, 30, 4, 44, 0)'
This is one of those times when Python's duck typing fails -- string
formatting really wants a tuple of arguments, and nothing else will do.
But you can slice a time.struct_time, and the result /is/ a genuine
tuple:
type(localtime[:6])
type 'tuple'
which is nice:
format % localtime[:6]
'2009-02-13 23:31:30'
But really what you wanted was probably
time.strftime('%Y-%m-%d %H:%M:%S', localtime)
'2009-02-13 23:31:30'
-- [mdw]
--
http://mail.python.org/mailman/listinfo/python-list
Re: Newbie question, list comprehension
Johannes Bauer wrote: Hello group, I'm currently doing something like this: import time localtime = time.localtime(1234567890) fmttime = %04d-%02d-%02d %02d:%02d:%02d % (localtime[0], localtime[1], localtime[2], localtime[3], localtime[4], localtime[5]) print fmttime For the third line there is, I suppose, some awesome python magic I could use with list comprehensions. I tried: fmttime = %04d-%02d-%02d %02d:%02d:%02d % ([localtime[i] for i in range(0, 5)]) But that didn't work: Traceback (most recent call last): File ./test.py, line 8, in ? fmttime = %04d-%02d-%02d %02d:%02d:%02d % ([localtime[i] for i in range(0, 5)]) TypeError: int argument required As it appearently passed the while list [2009, 02, 14, 0, 31, 30] as the first parameter which is supposed to be substituted by %04d. Is there some other way of doing it? Thanks a lot, Regards, Johannes You should look at time.strftime. It will do the formatting for you so you don't have to do it manually as you have. -Larry -- http://mail.python.org/mailman/listinfo/python-list
Newbie question, list comprehension
Hello group, I'm currently doing something like this: import time localtime = time.localtime(1234567890) fmttime = %04d-%02d-%02d %02d:%02d:%02d % (localtime[0], localtime[1], localtime[2], localtime[3], localtime[4], localtime[5]) print fmttime For the third line there is, I suppose, some awesome python magic I could use with list comprehensions. I tried: fmttime = %04d-%02d-%02d %02d:%02d:%02d % ([localtime[i] for i in range(0, 5)]) But that didn't work: Traceback (most recent call last): File ./test.py, line 8, in ? fmttime = %04d-%02d-%02d %02d:%02d:%02d % ([localtime[i] for i in range(0, 5)]) TypeError: int argument required As it appearently passed the while list [2009, 02, 14, 0, 31, 30] as the first parameter which is supposed to be substituted by %04d. Is there some other way of doing it? Thanks a lot, Regards, Johannes -- Wer etwas kritisiert muss es noch lange nicht selber besser können. Es reicht zu wissen, daß andere es besser können und andere es auch besser machen um einen Vergleich zu bringen. - Wolfgang Gerber in de.sci.electronics [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie question, list comprehension
Johannes Bauer wrote: Hello group, I'm currently doing something like this: import time localtime = time.localtime(1234567890) fmttime = %04d-%02d-%02d %02d:%02d:%02d % (localtime[0], localtime[1], localtime[2], localtime[3], localtime[4], localtime[5]) print fmttime For the third line there is, I suppose, some awesome python magic I could use with list comprehensions. I tried: fmttime = %04d-%02d-%02d %02d:%02d:%02d % ([localtime[i] for i in range(0, 5)]) The % operator here wants a tuple with six arguments that are integers, not a list. Try: fmttime = %04d-%02d-%02d %02d:%02d:%02d % tuple(localtime[i] for i in range(6)) As it appearently passed the while list [2009, 02, 14, 0, 31, 30] as the first parameter which is supposed to be substituted by %04d. Is there some other way of doing it? In this case, you can just use a slice, as localtime is a tuple: fmttime = %04d-%02d-%02d %02d:%02d:%02d % localtime[:6] Hope this helps! ^_^ -- Hans Nowak (zephyrfalcon at gmail dot com) http://4.flowsnake.org/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie question, list comprehension
Hans Nowak schrieb: In this case, you can just use a slice, as localtime is a tuple: fmttime = %04d-%02d-%02d %02d:%02d:%02d % localtime[:6] Hope this helps! ^_^ Ahh, how cool! That's *exactly* what I meant with awesome Python magic :-) Amazing language, I have to admit. Regards, Johannes -- Wer etwas kritisiert muss es noch lange nicht selber besser können. Es reicht zu wissen, daß andere es besser können und andere es auch besser machen um einen Vergleich zu bringen. - Wolfgang Gerber in de.sci.electronics [EMAIL PROTECTED] -- http://mail.python.org/mailman/listinfo/python-list
