I'd like to write a python function which adds all its arguments, using + operator. Number of arguments are not specified:
def my_func(*args):
return arg1 + arg2 + arg3 + ...
How do I do it?
Best Regards
4 Answers
Just use the sum built-in function
>>> def my_func(*args):
... return sum(args)
...
>>> my_func(1,2,3,4)
10
>>>
Edit:
I don't know why you want to avoid sum, but here we go:
>>> def my_func(*args):
... return reduce((lambda x, y: x + y), args)
...
>>> my_func(1,2,3,4)
10
>>>
Instead of the lambda you could also use operator.add.
Edit2:
I had a look at your other questions, and it seems your problem is using sum as the key parameter for max when using a custom class. I answered your question and provided a way to use your class with sum in my answer.
7 Comments
alwbtc
But I don't want to use
sum function.
eumiro
@alwbtc - why don't you want to?
Henry Gomersall
@eumiro perhaps he wants to use the
+ operator for cases other than numbers.
sloth
@HenryGomersall In this case he should simply add the
__radd__ method to his class.
Sarien
I assume you could reduce with operator.add instead of (lambda (x, y): x + y) in the second case, correct? (Seems correct.)
|
How about this:
def my_func(*args):
my_sum = 0
for i in args:
my_sum += i
return my_sum
If you don't want to use the += operator, then
my_sum = my_sum + i
answered Jul 17, 2012 at 10:15
Some programmer dude
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3 Comments
Henry Gomersall
This is generalised to make it different to
sum() by replacing my_sum = 0 with my_sum = args[0] and the loop to be for i in args[1:]. This now works on any list of objects with a sensible __add__ method.sloth
You could also leave the method as it is and implement a sensible
__radd__ method in your class.Henry Gomersall
@BigYellowCactus If it's not one's own class, then it's likely to be easier to change the function (e.g. strings).
If you definitely won't be using sum, then something like:
def func(*args, default=None):
from operator import add
try:
return reduce(add, args)
except TypeError as e:
return default
or functools.reduce in Py3
Comments
def sumall(*args):
sum_ = 0
for num in args:
sum_ += num
return sum_
print(sumall(1,5,7))
The output is 13.
*argsthenargsis a list of all arguments passed.sum? That's precisely what it does.