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John McErlain
12,508 PointsList not accepting *args
The following code returns the correct answer for a variety of different lists and tuples (for float types) on my computer. However, in the code challenge, there is an error message stating the list only takes one argument and I do not understand 'why'.
Thank-you
# If you need help, look up datetime.datetime.fromtimestamp()
# Also, remember that you *will not* know how many timestamps
# are coming in.
import datetime
def timestamp_oldest(*args):
timestamps = list(*args)
timestamps.sort()
conversion = datetime.datetime.fromtimestamp(timestamps[len(timestamps)-1], tz = None)
return conversion
3 Answers
Chris Freeman
Treehouse Moderator 68,441 PointsYour very close. When using *args as a parameter, you then reference it without the "*":
import datetime
def timestamp_oldest(*args):
timestamps = list(args) #<-- removed "*"
timestamps.sort()
#conversion = datetime.datetime.fromtimestamp(timestamps[len(timestamps)-1], tz = None)
conversion = datetime.datetime.fromtimestamp(timestamps[0]) #<-- "oldest" is lowest number
return conversion
John McErlain
12,508 PointsI appreciate your response Chris.
I have a follow-up question to this regarding the type of arguments passed into the function. When I test the function with: args = 999999,34,543267843,344565,894,9000873,32505000000,9872, I get a type error that "an integer is required". Does this have something to do with unpacking a tuple?
Chris Freeman
Treehouse Moderator 68,441 PointsWhen calling a function with a arguments in a tuple, you also have to unpack the tuple on the call. The *-expand can be used on the call as well as in the function definition.
# define arguments as tuple
In [78]: args = 999999,34,543267843,344565,894,9000873,32505000000,9872
# try calling function with tuple (single argument that is a tuple)
In [79]: timestamp_oldest(args)
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-79-1986d3f6ae1b> in <module>()
----> 1 timestamp_oldest(args)
<ipython-input-77-4b4cf9b1e3a2> in timestamp_oldest(*args)
3 timestamps.sort()
4 #conversion = datetime.datetime.fromtimestamp(timestamps[len(timestamps)-1], tz = None)
----> 5 conversion = datetime.datetime.fromtimestamp(timestamps[0]) #<-- "oldest" is lowest number
6 return conversion
7
TypeError: an integer is required (got type tuple)
# call function with * expanded tuple
In [82]: timestamp_oldest(*args)
Out[82]: datetime.datetime(1969, 12, 31, 16, 0, 34)
# call function with expanded arguments
In [83]: timestamp_oldest(999999,34,543267843,344565,894,9000873,32505000000,9872)
Out[83]: datetime.datetime(1969, 12, 31, 16, 0, 34)
John McErlain
12,508 PointsThis was very helpful. Thank-you Chris!