In <[EMAIL PROTECTED]>, 7stud wrote:
> On Apr 13, 3:36 am, "7stud" <[EMAIL PROTECTED]> wrote:
>>
>> > It is if the file is smaller than the buffer size.
>>
>> How is that relevant?
>>
>
> If I put 100 lines of text in a file with each line having 50
> characters, and I run this code:
>
> import sys
>
> lst = []
> for line in open("aaa.txt"):
> print "an iteration"
> lst.append(line)
> break
>
> print lst
>
>
> The output is:
>
> $ python test1.py
>
> an iteration
> ['helleo haljdfladj ahdflasdjf ds hdljfalsdjfdsljfds \n']
>
> It seems clear to me that the whole file wasn't first read into a
> buffer before the code started processing the data.
How is that clear to you? Why do you think the file was not loaded
completely into a buffer and only the first line from this buffer ends up
in `lst`?
Let's try this:
def main():
test_file = open('test.txt', 'w')
for i in xrange(100):
test_file.write('%d %s\n' % (i, 'x' * 50))
test_file.close()
test_file = open('test.txt', 'r')
for line in test_file:
print line
break
print '>%s<' % test_file.read(75)
test_file.close()
Output:
0 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
><
You see the read after the loop doesn't read anything because the file
content is in the buffer of the iterator. If the test file has more
lines, I tested it with 1000, the output looks like this:
0 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>xx
151 xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
152 xxxxxxxxxxxxx<
Ciao,
Marc 'BlackJack' Rintsch
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