I have a list of lists:
x = [[1,2,3], [4,5,6], [7,8,9], [2,2,0]]
I want to get the list whose sum of its elements is the greatest in the list. In this case [7,8,9].
I'd rather have a fancy map or lambda or list comprehension method than a for/while/if loop.
Best Regards
max takes a key argument, with it you can tell max how to calculate the value for each item in an iterable. sum will do nicely here:
max(x, key=sum)
Demo:
>>> x = [[1,2,3], [4,5,6], [7,8,9], [2,2,0]]
>>> max(x, key=sum)
[7, 8, 9]
If you need to use a different method of summing your items, you can specify your own functions too; this is not limited to the python built-in functions:
>>> def mymaxfunction(item):
... return sum(map(int, item))
...
>>> max([['1', '2', '3'], ['7', '8', '9']], key=mymaxfunction)
['7', '8', '9']
key, isn't it? If you have trouble with that, post a new question here on SO and we can help you again.sum with your own function, either max(x, key=lambda x: some expression) or define a new function (def foobar(x): return some calculation) and use that for the key (max(x, key=foobar)).For completeness and as @Martijn beat me to the most elegant answer - I'll just throw in the option before the key= parameter was available in Python (but if you're using < 2.5 - you should really upgrade) and how ugly it use to be:
x = [[1,2,3], [4,5,6], [7,8,9], [2,2,0]]
with_idx = ( (sum(v), i) for i,v in enumerate(x))
print x[max(with_idx)[1]]
num = [[1, 2, 3], [4, 5, 6], [10, 11, 12], [7, 8, 9]]
index = 0
max_index = 0
sum_max = 0
for list in num:
>>>>sum_list = 0
>>>>for x in list:
>>>>>>>>sum_list += x
>>>>if sum_list > sum_max:
>>>>>>>>sum_max = sum_list
>>>>>>>>max_index = index
>>>>index += 1
print(num[max_index])`enter code here`
