#26001: mention in the tutorial that files in binary mode expect bytes, not str.

This commit is contained in:
Ezio Melotti 2016-01-12 11:27:30 +02:00
parent f418db2e8c
commit 397bb2486a
1 changed files with 8 additions and 7 deletions

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@ -271,10 +271,11 @@ The rest of the examples in this section will assume that a file object called
``f`` has already been created.
To read a file's contents, call ``f.read(size)``, which reads some quantity of
data and returns it as a string or bytes object. *size* is an optional numeric
argument. When *size* is omitted or negative, the entire contents of the file
will be read and returned; it's your problem if the file is twice as large as
your machine's memory. Otherwise, at most *size* bytes are read and returned.
data and returns it as a string (in text mode) or bytes object (in binary mode).
*size* is an optional numeric argument. When *size* is omitted or negative, the
entire contents of the file will be read and returned; it's your problem if the
file is twice as large as your machine's memory. Otherwise, at most *size* bytes
are read and returned.
If the end of the file has been reached, ``f.read()`` will return an empty
string (``''``). ::
@ -315,11 +316,11 @@ the number of characters written. ::
>>> f.write('This is a test\n')
15
To write something other than a string, it needs to be converted to a string
first::
Other types of objects need to be converted -- either to a string (in text mode)
or a bytes object (in binary mode) -- before writing them::
>>> value = ('the answer', 42)
>>> s = str(value)
>>> s = str(value) # convert the tuple to string
>>> f.write(s)
18