August 2006
Intermediate to advanced
1600 pages
51h 46m
English
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Standard Streams
The sys module is also the
place where the standard input, output, and error streams of your Python programs live:
>>>for f in (sys.stdin, sys.stdout, sys.stderr): print f
...
<open file '<stdin>', mode 'r' at 762210>
<open file '<stdout>', mode 'w' at 762270>
<open file '<stderr>', mode 'w' at 7622d0>The standard streams are simply preopened Python file objects
that are automatically connected to your program’s standard streams
when Python starts up. By default, all of them are tied to the console
window where Python (or a Python program) was started. Because the
print statement and raw_input functions are really nothing more
than user-friendly interfaces to the standard output and input
streams, they are similar to using stdout and stdin in sys directly:
>>>print 'hello stdout world'hello stdout world >>>sys.stdout.write('hello stdout world' + '\n')hello stdout world >>>raw_input('hello stdin world>')hello stdin world>spam'spam' >>>print 'hello stdin world>',; sys.stdin.readline( )[:-1]hello stdin world>eggs'eggs'