automatically split data in list and order list elements and send to function

I have recently created a GUI, which contents tables. User can insert values in cells. As shown figur below.

I want to use values to make some calculation based on values given by user. Rows can be added and removed based on choice of user. with other word, the data I get from user could come from just one row or several rows.

I manage to obtain all values from tables automatically and assign them to python list. Each row gives 5 elements in the list.

I have achieved that. Data in python list have to be processed and organised. This is exactly I want to have help. Because few dags I have been thinking, and I can not figure out, how to continue...

Python data as list from table. as an example.

data = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, '', 11, 12, 13, 14] 

What I want to achieve!

I want to split list into 3 times len(data).

I have also achieved this.

def split_seq(seq, num_pieces):
    start = 0
    for i in range(num_pieces):
        stop = start + len(seq[i::num_pieces])
        yield seq[start:stop]
        start = stop

for data in split_seq(data, int(len(data)/5)):
    print(data)

Output would be:

[1, 2, 3, 4, 5]
[6, 7, 8, 9, 10]
['', 11, 12, 13, 14]

The difficulty for me starts here.

I want to take each splitted list and throw them into a if condition and store values as variables and message those values to a external function.

Something like this below:

for i in range(len(splitted_list1)):
    if splitted_list1[0] == '':
       do nothing
    else:
       x_+str(i)= splitted_list1[i]
       externalfunc(x_1,x_2,x_3,x_4,x_5)

for i in range(len(splitted_list2)):
    if splitted_list2[0] == '':
       do nothing
    else:
       x_+str(i)= splitted_list2[i]
       externalfunc(x_1,x_2,x_3,x_4,x_5)

continues depending on number of splitted_lists

..............

I appreciate any help and you are welcome to come with another idea to come around this.