iteration in list with math operations

Question

i have test list

a = [1,2,3,4,5,6,7,8,9,10]

for example, i want to squared some of them and get sum of them. then i want to divide this sum to 2 . and then i want raise to the power 1/4

code is:

result = ((a[0]**2+a[1]**2)/2)**(1/4)

prolbem is that i define each value. in this example its a[0] and a[1]

i want just get some variable of number of iterable objects (in my case it's n = 2 )

for n = 3 its should be equal to:

((a[0]**2+a[1]**2+a[2]**2)/2)**(1/4)

i can get this values with

for i in range(3):
    print(a[i])

with output:

1
2
3

but idk how to add them to my math operation code

Answer 1

This should do it:

square=0
for i in range(3):
    square=square+a[i]**2
    if i==2:
        square=(square/2)**(1/4)
print(square)

This squares each number and adds it to the square variable. If it is on the last iteration of i, it divides square by 2 and raises it to the power of 1/4

Answer 2

You can create a dictionary of operations to perform and apply them on part of your list. this needs python 3.7+ to guarantee insert-order of rules in dict == order they get applied later:

a = [1,2,3,4,5,6,7,8,9,10]

# rules
ops = {"square_list" : lambda x: [a**2 for a in x], # creates list
       "sum_list"    : lambda x : sum(x),           # skalar
       "div_2"       : lambda x : x/2,              # skalar
       "**1/4"       : lambda x: x**(1/4)}          # skalar


n_min = 0
for m in range(1,len(a)): 
    # get list part to operate on 
    parts = a [n_min:m]
    print(parts)

    # apply rules
    for o in ops:
        parts = ops[o](parts)

    # print result
    print(parts)

Output:

[1]
0.8408964152537145
[1, 2]
1.2574334296829355
[1, 2, 3]
1.6265765616977856
[1, 2, 3, 4]
1.9679896712654303
[1, 2, 3, 4, 5]
2.2899878254809036
[1, 2, 3, 4, 5, 6]
2.597184780029334
[1, 2, 3, 4, 5, 6, 7]
2.892507608519078
[1, 2, 3, 4, 5, 6, 7, 8]
3.1779718278112656
[1, 2, 3, 4, 5, 6, 7, 8, 9]
3.4550450628484315