process a python function on windows of rows in a file code example

Example: python 3 text file leng

f = open("filename", "r") #Load file in any mode that's able to read, ie r, r+, w+ etc

#to get length
len(f.readlines())

#To iterate over each line
for line in f.readlines(): #file.readlines(), splits the file into a list, where each element is a seperate line
  print(line)