read and write to file python

with open('filename', 'a') as f: # able to append data to file
	f.write(var1) # Were var1 is some variable you have set previously
	f.write('data') 
	f.close() # You can add this but it is not mandatory 

with open('filename', 'r') as f: # able to read data from file ( also is the default mode when opening a file in python)

with open('filename', 'x') as f: # Creates new file, if it already exists it will cause it to fail

with open('filename', 't') as f: # opens the file in text mode (also is defualt)

with open('filename', 'b') as f: # Use if your file will contain binary data
  
with open('filename', 'w') as f: # Open file with ability to write, will also create the file if it does not exist (if it exists will cause it to fail)
  
with open('filename', '+') as f: # Opens file with reading and writing

# You can combine these as you like with the + for reading and writing

# "with" closes file for you after use, even if error encountered
# r - read, w - write, rb - read binary, wb - write binary

with open('dog_breeds.txt', 'r') as reader:
     # Read and print the entire file line by line
     for line in reader:
         print(line, end='')

file = open(“testfile.txt”, “r+”) 

f = open("demofile2.txt", "a")
f.write("Now the file has more content!")
f.close()

with open('pagehead.section.htm','r') as f:
    output = f.read()

for i in range(10):
     f.write("This is line %d\r\n" % (i+1))