Iterate 2D arrays and assignment to variables of function in python

Question

I am new to Python. I have a 2D array (10,4) and need to iterate array elements by assigning four values of each row to four variables of function (x1, x2, x3, x4), and return function output. Please have a look at my code and give me suitable suggestions. Thanks

import pandas as pd
import numpy as np

nv = 4              
lb = [0, 0, 0, 0]
ub = [20, 17, 17, 15]
n = 10             

def random_population(nv,n,lb,ub):
    pop = np.zeros((n, nv)) 
    for i in range(n):
        pop[i,:] = np.random.uniform(lb,ub)
    return pop

population = random_population(nv, n, lb, ub)

i = 0 #row number
j = 0 # col number

rows = population.shape[0]
cols = population.shape[1]

x1 = population[i][j]
x2 = population[i][j+1]
x3 = population[i][j+2]
x4 = population[i][j+3]

def test(x1, x2, x3, x4):   
##Assignment statement
    y = x1+x2+x3+x4         
    return y
test(x1, x2, x3, x4)

Answer 1

The question is not clear, but if I got the goal correctly and the author needs just iterating based on the title (instead of vectorizing as mentioned by Michael Szczesny in the comments), the following loop will put each row of the population array into the test function:

for row in population:
    x1, x2, x3, x4 = row
    test(x1, x2, x3, x4)

or

for row in population:
    test(*row)