python read file line by line

with open("file.txt") as file_in:
    lines = []
    for line in file_in:
        lines.append(line)

with open(filename) as f:
    content = f.readlines()
# you may also want to remove whitespace characters like `\n` at the end of each line
content = [x.strip() for x in content] 

# Open the file with read only permit
f = open('my_text_file.txt')
# use readline() to read the first line 
line = f.readline()
# use the read line to read further.
# If the file is not empty keep reading one line
# at a time, till the file is empty
while line:
    # in python 2+
    # print line
    # in python 3 print is a builtin function, so
    print(line)
    # use realine() to read next line
    line = f.readline()
f.close()

# Python code to 
# demonstrate readlines() 
  
L = ["Geeks\n", "for\n", "Geeks\n"] 
  
# writing to file 
file1 = open('myfile.txt', 'w') 
file1.writelines(L) 
file1.close() 
  
# Using readlines() 
file1 = open('myfile.txt', 'r') 
Lines = file1.readlines() 
  
count = 0
# Strips the newline character 
for line in Lines: 
    print("Line{}: {}".format(count, line.strip())) 

with open('yourfile.txt','r') as f:
    lines = f.readlines()
    f.close()

from os import path
if path.exists(file):
	for f in open(file):
  		print(f)

# Using readlines() 
file1 = open('myfile.txt', 'r') 
Lines = file1.readlines()