How to Transpose a string matrix in python without numpy

I was solving the problem GridChallenge on HackerRank. In hacker rank sometimes you are not allowed to import numpy. I wanted to transpose a square matrix nonetheless, so I came up with this method which I am happy to share.

#Transpose Function in Python
def get_i (somestringlist,i):   return somestringlist [i]
def get_col_i (grid,j)      :   return "".join (list (map (get_i , grid , [j for p in range ( len (grid) ) ] ) ))
def t_grid (grid):
    grid_list  =   [grid for i in range (len (grid[0]) )]
    index_list =   [i    for i in range (len (grid[0]))]
    return list (map (get_col_i , grid_list , index_list))

#Example test Case
from time import time 
start        = time ()
grid     = ["aepo",
          "poip",
          "iope"]
trans_grid   = t_grid(grid)     
end          = time ()
process_time = end - start
print (trans_grid , process_time  )
print (process_time * 1000000)

It would take about 17 seconds to transpose a 1 million rows matrix of 4 letters text.

Thank you for your interest and please leave in the comments if you would like any further elaboration on the code. I just tried to keep the solution compact but I can elaborate on its logic and implementation if required.