Oh, I was thinking of proper subexpressions. sage: def subexpressions(e): ....: res = [e] ....: if not hasattr(e, '_operands'): ....: return res ....: for op in e._operands: ....: res += subexpressions(op) ....: return res ....: sage: subexpressions(exp(x)+1) [e^x + 1, e^x, exp, x, 1] sage: exp(x) in subexpressions(exp(x)+1) True sage: exp(x) in subexpressions(exp(x)) True
--Mike On 10/1/07, Ondrej Certik <[EMAIL PROTECTED]> wrote: > > > Here is some code that I think will do the trick. > > > > sage: def subexpressions(e): > > ....: res = [] > > ....: if not hasattr(e, '_operands'): > > ....: return [] > > ....: for op in e._operands: > > ....: res.append(op) > > ....: res += subexpressions(op) > > ....: return res > > ....: > > sage: e = exp(x)+1 > > sage: f = exp(x) > > sage: subexpressions(e) > > [e^x, exp, x, 1] > > sage: f in subexpressions(e) > > True > > Thanks for a quick response. It doesn't work well though: > > sage: exp(x) in subexpressions(exp(x)+1) > True > sage: exp(x) in subexpressions(exp(x)) > False > > But both should return True. Unfortunately I need this to work > reliably, otherwise the algorithm will not work. > > Ondrej > > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://sage.scipy.org/sage/ and http://modular.math.washington.edu/sage/ -~----------~----~----~----~------~----~------~--~---
