On Mon, Feb 29, 2016 at 9:39 AM, Mark Lawrence <breamore...@yahoo.co.uk> wrote:
> On 29/02/2016 13:45, jonas.thornv...@gmail.com wrote: > >> I have a problem programming uniform networks, "x nodes with y links" >> that turn out to be really hairy to solve for me and i feel i really lack >> the programming features >> >> "Actually i program in javascript" but the problem seem general for all >> programming languages including Pyhton. >> >> For a beautiful solution it would require "If in list/array return >> boolean" "If not in list/array return boolean". >> >> But there is no such feature Python nor Javascript, so instead i set >> boolean value "inlist" to false and loop thru, to see if it is already in >> list. If not it is added to list. >> >> So if the current node i generate links for is x and i try to generate a >> link to node z, and z's links exhausted i will add it to exhausted list. >> >> And if there is node-x exhausted entries in list, well then script should >> break because it will lock into a cycle. The cyclic lockup is due to only a >> subset of the networks on the form (links*deep)+1=nodes is possible. >> >> So what i need is to know howto write "if list/array ***empty*** do >> {something}" >> >> I sure know howto check if an array have 1 element 2,3,4 but how do you >> check for empty. >> >> I think it is crazy that you can not do general comparissons of the type >> If in list/array >> If not in list/array >> >> But it is even more crazy that you can not check if list/array is empty, >> that is just madness. >> >> > Please see > https://docs.python.org/3/library/stdtypes.html#truth-value-testing > > -- > My fellow Pythonistas, ask not what our language can do for you, ask > what you can do for our language. > > Mark Lawrence > > -- > https://mail.python.org/mailman/listinfo/python-list > >>> l = [] >>> l [] >>> if l: ... print 'not empty' ... >>> -- Joel Goldstick http://joelgoldstick.com/ <http://joelgoldstick.com/stats/birthdays> http://cc-baseballstats.info/ -- https://mail.python.org/mailman/listinfo/python-list