diff options
| -rw-r--r-- | Doc/library/functions.rst | 15 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Documentation/2018-12-23-23-52-31.bpo-34764.DwOGeT.rst | 1 |
2 files changed, 9 insertions, 7 deletions
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst index 24a158f..b49d752 100644 --- a/Doc/library/functions.rst +++ b/Doc/library/functions.rst @@ -810,13 +810,14 @@ are always available. They are listed here in alphabetical order. See also :ref:`typeiter`. - One useful application of the second form of :func:`iter` is to read lines of - a file until a certain line is reached. The following example reads a file - until the :meth:`~io.TextIOBase.readline` method returns an empty string:: - - with open('mydata.txt') as fp: - for line in iter(fp.readline, ''): - process_line(line) + One useful application of the second form of :func:`iter` is to build a + block-reader. For example, reading fixed-width blocks from a binary + database file until the end of file is reached:: + + from functools import partial + with open('mydata.db', 'rb') as f: + for block in iter(partial(f.read, 64), ''): + process_block(block) .. function:: len(s) diff --git a/Misc/NEWS.d/next/Documentation/2018-12-23-23-52-31.bpo-34764.DwOGeT.rst b/Misc/NEWS.d/next/Documentation/2018-12-23-23-52-31.bpo-34764.DwOGeT.rst new file mode 100644 index 0000000..d2a7f1b --- /dev/null +++ b/Misc/NEWS.d/next/Documentation/2018-12-23-23-52-31.bpo-34764.DwOGeT.rst @@ -0,0 +1 @@ +Improve example of iter() with 2nd sentinel argument.
\ No newline at end of file |