how to add user input to file and print

[newbieinpython]

Here are my code below, i have two issues: 1) user input was overwritten. 2)i don't see the line is printed. What did i miss? please help.
------------------------------------------------

#!usr/local/bin/python3
f = open('python1/inputter.txt', 'w')
while True:
    i = input("Write a sentence:")
    f.write(i)
    if i == "":
        break
f = open('python1/inputter.txt', 'r')
f.read()
for line in f:
    print(line)

[zmbd]

line 2, file opened for write not append.
http://docs.python.org/library/functions.html.
Also between 7 and 8 you do not explicitly close the file... this is highly recommended to do (section 7.2.1 just before 7.2.2): http://docs.python.org/tutorial/inputoutput.html

[newbieinpython]

@zmbd
Thanks for reponse. But I still don't see you are helping with my problem.

[zmbd]

read the documentation I linked for you.

[dwblas]

Note that
f.write(i)
sends the data to the buffer to be written to file at some future time as it is more efficient to read or write a group of records at once. Also, the file will have zero length (no data) when you read it because the end-of-file pointer is generally updated when the file is closed and you never close the file. So you have to explicitly close the file which will flush the buffers and update to the correct length. Also, to print the contents you should use
print f.read()
A link to an on-line book on file handling and the use of readlines() plus iterating over the file. [edited to remove off-topic comments]