CODEWITHSUNDEEP
pythonpython-3.x
user1870662
user1870662

Reputation: 13

How to read from a file using only readline()

The code i have right now is this 

f = open(SINGLE_FILENAME)
lines = [i for i in f.readlines()]

but my proffessor demands that

You may use readline(). You may not use read(), readlines() or iterate over the open file using for.

any suggestions? thanks

Upvotes: 0

Views: 135

Answers (2)

jfs
jfs

Reputation: 414215

You could use a two-argument iter() version:

lines = iter(f.readline, "")

If you need a list of lines:

lines = list(lines)

Upvotes: 4

Joshua D. Boyd
Joshua D. Boyd

Reputation: 4856

First draft:

lines = []
with open(SINGLE_FILENAME) as f:
    while True:
        line = f.readline()
        if line:
            lines.append(line)
        else:
            break

I feel fairly certain there is a better way to do it, but that does avoid iterating with for, using read, or using readlines.

You could write a generator function to keep calling readline() until the file was empty, but that doesn't really seem like a large improvement here.

Upvotes: 3

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