搜搜做题作业网PYTHON round
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PYTHON round
For
this problem,we'll round an int value up to the next multiple of 10 if
its rightmost digit is 5 or more,so 15 rounds up to 20.Alternately,
round down to the previous multiple of 10 if its rightmost digit is less
than 5,so 12 rounds down to 10.Given 3 ints,a b c,return the sum of
their rounded values.To avoid code repetition,write a separate helper
"def round10(num):" and call it 3 times.
Example Output:round_sum(16,17,18) → 60round_sum(12,13,14) → 30round_sum(6,4,4) → 10
For
this problem,we'll round an int value up to the next multiple of 10 if
its rightmost digit is 5 or more,so 15 rounds up to 20.Alternately,
round down to the previous multiple of 10 if its rightmost digit is less
than 5,so 12 rounds down to 10.Given 3 ints,a b c,return the sum of
their rounded values.To avoid code repetition,write a separate helper
"def round10(num):" and call it 3 times.
Example Output:round_sum(16,17,18) → 60round_sum(12,13,14) → 30round_sum(6,4,4) → 10
$ python
Python 2.7.3 (default, Jan 2 2013, 16:53:07)
[GCC 4.7.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> def round_sum(*args):
... return sum(map(lambda x: round(x, -1), args))
...
>>> round_sum(16, 17, 18)
60.0
>>> round_sum(12, 13, 14)
30.0
>>> round_sum(6, 4, 4)
10.0
>>>
再问： 能不能解析下。我刚刚接触对于语法不太熟悉。
再答： map(func, iterable) 对iterable里的每个元素调用func函数, 返回值组成新的列表
再问： 这个我当学习样本了。如果我用loop来解决这个问题的话你能不能给我个大概，在loop里我如何round作为数学白痴的我实在是太难了。
再答： # usage loop
summary = 0
for item in iterable:
summary += round(item, -1)
Python 2.7.3 (default, Jan 2 2013, 16:53:07)
[GCC 4.7.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> def round_sum(*args):
... return sum(map(lambda x: round(x, -1), args))
...
>>> round_sum(16, 17, 18)
60.0
>>> round_sum(12, 13, 14)
30.0
>>> round_sum(6, 4, 4)
10.0
>>>
再问： 能不能解析下。我刚刚接触对于语法不太熟悉。
再答： map(func, iterable) 对iterable里的每个元素调用func函数, 返回值组成新的列表
再问： 这个我当学习样本了。如果我用loop来解决这个问题的话你能不能给我个大概，在loop里我如何round作为数学白痴的我实在是太难了。
再答： # usage loop
summary = 0
for item in iterable:
summary += round(item, -1)