How can I change the RGB channels from pointclouds.ply file with relative luminance?

Question

I have separated the rgb channel into a new dataframe from x,y, z coord. Now I am stuck at iterating thw conversion calculations over 800k rows within the rgb dataframe. I dont know how to go through each of the element and convert them.

I have tried creating a loop over the dataframe and calculate them accordingly, but it doesnt change the values idk.

I have used the formulas given here: https://stackoverflow.com/a/56678483/12059118

p.s: I am a rookie so I know how ugly&stupıd my code looks like but that's just my starting :P

from pyntcloud import PyntCloud
import numpy as np
import pandas as pd


cloud = PyntCloud.from_file("longdress_vox10_1051.ply")
#print(cloud)

#scene = cloud.plot(return_scene=True)
data = cloud.points

df1 = data.iloc[:, 3:6] 

df1= df1/255 


for index, row in df1.iterrows():    
    if row <= 0.04045:
        print(row)
        row = row/12.92
        print(row)
    else:
        row = ((row + 0.055)/1.055)**2.4
        print(row)
    print(row)


for i in range(len(df1)):
    print(i.type())
    
    if df1['red'][i] <= 0.04045:
        df1['red'][i]= df1['red']/12.92
    else:
        df1['red'][i] = ((df1['red'][i] + 0.055)/1.055)**2.4
          
            #print(df1.head(:3))






#df1['red'] = df1['red']*0.2126
#df1['green'] = df1['green']*0.7152
#df1['blue'] = df1['blue']*0.0722