On Sun, Nov 18, 2012 at 3:03 PM, Shriramana Sharma <samj...@gmail.com> wrote: > I'll be back with more queries later. :-)
OK so here's my next query on the same thread: In [1]: from sympy import * ...: i,j=symbols('i j',integer=True) ...: lamb=list(symbols('lamb:4')) ...: n=3 ...: summation(lamb[i]*(-1)**(n-j)*binomial(i,n-j),(i,n-j,n)) ...: --------------------------------------------------------------------------- TypeError Traceback (most recent call last) /mnt/sda7/samjnaa-precise/<ipython-input-1-0af017dc9283> in <module>() 3 lamb=list(symbols('lamb:4')) 4 n=3 ----> 5 summation(lamb[i]*(-1)**(n-j)*binomial(i,n-j),(i,n-j,n)) 6 TypeError: list indices must be integers, not Symbol OK so since lamb is a Python list and not a SymPy list (is there such a thing?) Python tries to dereference it using i and throws the error. Basically I want to do a summation of lamb0 ... lamb3 with the appropriate coefficients. What to do? Thanks! -- Shriramana Sharma -- You received this message because you are subscribed to the Google Groups "sympy" group. To post to this group, send email to sympy@googlegroups.com. To unsubscribe from this group, send email to sympy+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.