CODEWITHSUNDEEP
pythonfile
peonicles
peonicles

Reputation: 1637

Read from file after write, before closing

I'm trying to read from an originally empty file, after a write, before closing it. Is this possible in Python?

with open("outfile1.txt", 'r+') as f:
    f.write("foobar")
    f.flush()
    print("File contents:", f.read())

Flushing with f.flush() doesn't seem to work, as the final f.read() still returns nothing.

Is there any way to read the "foobar" from the file besides re-opening it?

Upvotes: 13

Views: 10331

Answers (3)

zmo
zmo

Reputation: 24812

You need to reset the file object's index to the first position, using seek():

with open("outfile1.txt", 'r+') as f:
    f.write("foobar")
    f.flush()

    # "reset" fd to the beginning of the file
    f.seek(0)
    print("File contents:", f.read())

which will make the file available for reading from it.

Upvotes: 14

user2357112
user2357112

Reputation: 280236

Seek back to the start of the file before reading:

f.seek(0)
print f.read()

Upvotes: 2

Pavel Anossov
Pavel Anossov

Reputation: 62868

File objects keep track of current position in the file. You can get it with f.tell() and set it with f.seek(position).

To start reading from the beginning again, you have to set the position to the beginning with f.seek(0).

http://docs.python.org/2/library/stdtypes.html#file.seek

Upvotes: 3

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