To read some text file, in C or Pascal, I always use the following snippets to read the data until EOF:
while not eof do begin
readline(a);
do_something;
end;
Thus, I wonder how can I do this simple and fast in Python?
Loop over the file to read lines:
with open('somefile') as openfileobject:
for line in openfileobject:
do_something()
File objects are iterable and yield lines until EOF. Using the file object as an iterable uses a buffer to ensure performant reads.
You can do the same with the stdin (no need to use raw_input()
:
import sys
for line in sys.stdin:
do_something()
To complete the picture, binary reads can be done with:
from functools import partial
with open('somefile', 'rb') as openfileobject:
for chunk in iter(partial(openfileobject.read, 1024), b''):
do_something()
where chunk
will contain up to 1024 bytes at a time from the file, and iteration stops when openfileobject.read(1024)
starts returning empty byte strings.