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# sum(List) -- sum the elements of a list

- Function: sum

## Description

sum v yields the sum of the elements in the list v.

    i1 : sum {1,2,3,4,5}

    o1 = 15

The sum of an empty list is the integer 0.

    i2 : sum {}

    o2 = 0

    i3 : class oo

    o3 = ZZ

    o3 : Ring

When summing a possibly empty list of elements from a ring, one may use promote to ensure the result is always in the same ring.

    i4 : R = QQ[x_1 .. x_10];

    i5 : f = n -> sum for i from 1 to n list x_i;

    i6 : f 4

    o6 = x  + x  + x  + x
          1    2    3    4

    o6 : R

    i7 : f 0

    o7 = 0

    i8 : class oo

    o8 = ZZ

    o8 : Ring

    i9 : g = n -> promote(sum for i from 1 to n list x_i, R);

    i10 : g 10

    o10 = x  + x  + x  + x  + x  + x  + x  + x  + x  + x
           1    2    3    4    5    6    7    8    9    10

    o10 : R

    i11 : g 0

    o11 = 0

    o11 : R

    i12 : class oo

    o12 = R

    o12 : PolynomialRing

## See also

- sum -- compute the sum

## Ways to use this method:

- sum(List) -- sum the elements of a list

The source of this document is in /build/macaulay2-88fgJW/macaulay2-1.25.11+ds/M2/Macaulay2/packages/Macaulay2Doc/functions/sum-doc.m2:44:0.