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
|