Pfthb

i'm struggling to work out how to use a loop to run through a list which contains 4 array values being "a_value", "b_value", "c_value", "d_value". Each of my arrays in this list have 23 elements. the outcome im looking for is for a loop to run though the list adding all 23 elements of each array. E.G. total of "a_value" then total of "b_value" and so on. this is what i have so far.
Thank you guys.

class node():
 def __init__(self, dataval = None):
 self.dataval = dataval
 self.nextval = None

class linked_list():
 def __init__(self):
 self.headval = None

 def listprint(self):
 printval = self.headval
 while printval != None:
 print (printval.dataval)
 printval = printval.nextval 


arraylist = linked_list()
arraylist.headval = node(a_value) # each '""_value' has 23 integer values 
in them
e2 = node(b_value)
e3 = node(c_value)
e4 = node(d_value) 

arraylist.headval.nextval = e2
e2.nextval = e3
e3.nextval = e4

arraylist.listprint()

i = 1
x = 1
total_a = 0
total_b = 0
total_c = 0
total_d = 0

for n in arraylist:
 for z in range(len(n)-1)
 value_a = int(a_value[i])
 total_a+=value_a
 i+= 1
 x+=1 

you can try something like this:

 a_value = [1,2,3]
 b_value = [4,5,6]
 c_value = [7,8,9]
 d_value = [10,11,12]

 class node():
 def __init__(self, dataval = None):
 self.dataval = dataval
 self.nextval = None


 class linked_list():
 def __init__(self):
 self.headval = None

 def listprint(self):
 printval = self.headval
 while printval != None:
 print (printval.dataval)
 printval = printval.nextval


 arraylist = linked_list()
 arraylist.headval = node(a_value)
 e2 = node(b_value)
 e3 = node(c_value)
 e4 = node(d_value)

 arraylist.headval.nextval = e2
 e2.nextval = e3
 e3.nextval = e4

 node = arraylist.headval # fetch head node 
 nextval = node.nextval # fetch next to node
 list = 
 list.append(node.dataval) # enter all head list

 while nextval: # this loop will break as nextval is none
 node = node.nextval # node now becomes next and repeat
 if hasattr(node, 'nextval'):
 nextval = node.nextval
 else:
 nextval = None
 list.append(node.dataval)

 sum = 0

 for x in list: # sum in the end or break into 23 for all separate
 for y in x:
 sum+=y

 print(list, sum)

 #OUTPUT [[1, 2, 3], [4, 5, 6], [7, 8, 9], [10, 11, 12]] 78

Works fine :)