Python Course 9: File Objects

Write to Disk

my_file = open("sample.txt","w")
my_file.write("Sausage\n")
my_file.write("Egg\n")
my_file.write("Chips\n")

my_file.close()

my_file = open("hello.txt","w") 
lines_of_text = ["Sausage\n","Egg\n","Chips\n"] 
my_file.writelines(lines_of_text) 
my_file.close() 

Read from Disk

Read One Line from Disk

my_file = open("sample.txt","r")
print(my_file.readline())
my_file.close()

Read all Lines and Strip Line Breaks

file = open("sample.txt", "r") 
for line in file: 
    print(line.rstrip('\n'))

or

file = open("sample.txt", "r") 
for line in file: 
    print(line, end = "")

Read Lines into a List

my_file = open("sample.txt","r")
print(my_file.readlines())

my_file.close()

Exercise

1. In Python, open a file object with write access to a file called “people.txt”.
   1. Write the following three names to the file: George, Alison, Jasprit.
   2. Close the file object
   3. Open the file in Notepad and check the names were written correctly.
2. Use Notepad to create a text file called “shopping.txt”. Add the following items, one item per line: milk, sugar, flour, 6 eggs, butter, raisins, raspberry jam
   1. In Python, open a file object with read access to shopping.txt
   2. Use a for loop to print out the items in your shopping list
3. In Python, open a file object with write access to a file called “todo list.txt”
   • Write a question loop that will prompt the user “Add another item”
   • If the user enters “N” the loop will terminate and the file object will be closed.
   • Otherwise, the item entered will be written to the file object
   • Run your program and check that the todo list is created.