Clever Geek Handbook

How do I create an indexed variable in sympy?

x,i,n = symbols("x i n")
summation(x,(i,1,n))

How do I do x

with the index i

?

+5


source to share


1 answer


Without a numeric upper limit, it won't do anything, but otherwise you can use a function expression or an indexed variable:



>>> Sum(Indexed('x',i),(i,1,3))
Sum(x[i], (i, 1, 3))
>>> _.doit()
x[1] + x[2] + x[3]

>>> x = Function('x')
>>> Sum(x(i),(i,1,3)).doit()
x(1) + x(2) + x(3)

>>> Sum(x(i),(i,1,n)).doit()
Sum(x(i), (i, 1, n))
+8


source






More articles:


All Articles