sum up numbers in a list

[sharon kim]

hi all,

i have a list, for example;

 L=[]
 L.append('10')
 L.append('15')
 L.append('20')
 len(L)
3
 print L
['10', '15', '20']

is there a way to sum up all the numbers in a list?  the number of objects
in the list is vary, around 50 to 60. all objects are 1 to 3 digit positive
numbers.

all i can think of is check the length of the list (in the above example,
3), then L[0]+L[1]+L[2] ..

is there a better way to do the job? thanks.
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Re: sum up numbers in a list

[Fredrik Lundh]

sharon kim wrote:


i have a list, for example;

  L=[]
  L.append('10')
  L.append('15')
  L.append('20')
  len(L)
3
  print L
['10', '15', '20']

is there a way to sum up all the numbers in a list?  the number of 
objects in the list is vary, around 50 to 60. all objects are 1 to 3 
digit positive numbers.


the for-in statement is your friend:

S = 0
for item in L:
S += int(item)

it can also be used in-line (this is called a generator expression):

S = sum(int(v) for v in L)

or even hidden inside a built-in helper function:

S = sum(map(int, L))

/F

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Re: sum up numbers in a list

[c james]

 L=['10','15','20']
 sum(int(x) for x in L)
45

or
 sum(map(int,L))
45

sharon kim wrote:

hi all,

i have a list, for example;

  L=[]
  L.append('10')
  L.append('15')
  L.append('20')
  len(L)
3
  print L
['10', '15', '20']

is there a way to sum up all the numbers in a list?  the number of 
objects in the list is vary, around 50 to 60. all objects are 1 to 3 
digit positive numbers.


all i can think of is check the length of the list (in the above 
example, 3), then L[0]+L[1]+L[2] ..


is there a better way to do the job? thanks.


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http://mail.python.org/mailman/listinfo/python-list

Re: sum up numbers in a list

[sharon kim]

brilliant, thank you both of you, i will try that out later.

:)

On Wed, Aug 27, 2008 at 1:34 AM, c james [EMAIL PROTECTED] wrote:

  L=['10','15','20']
  sum(int(x) for x in L)
 45

 or
  sum(map(int,L))
 45


 sharon kim wrote:

 hi all,

 i have a list, for example;

   L=[]
   L.append('10')
   L.append('15')
   L.append('20')
   len(L)
 3
   print L
 ['10', '15', '20']

 is there a way to sum up all the numbers in a list?  the number of objects
 in the list is vary, around 50 to 60. all objects are 1 to 3 digit positive
 numbers.

 all i can think of is check the length of the list (in the above example,
 3), then L[0]+L[1]+L[2] ..

 is there a better way to do the job? thanks.


 --
 http://mail.python.org/mailman/listinfo/python-list

--
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Re: sum up numbers in a list

[Terry Reedy]

sharon kim wrote:


is there a way to sum up all the numbers in a list?


 help(sum)
sum(...)
sum(iterable[, start]) - value

Returns the sum of an iterable of numbers (NOT strings) plus the value
of parameter 'start' (which defaults to 0).  When the iterable is
empty, returns start.

 L=[28,39,20,78490,37373,22,2,33,4,5]
 sum(L)
116016

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