StringIO
— 按文件方式读写字符串
¶
This module implements a file-like class,
StringIO
, that reads and writes a string buffer (also known as
memory files
). See the description of file objects for operations (section
文件对象
). (For standard strings, see
str
and
unicode
)。
StringIO.
StringIO
(
[
buffer
]
)
¶
当
StringIO
object is created, it can be initialized to an existing string by passing the string to the constructor. If no string is given, the
StringIO
will start empty. In both cases, the initial file position starts at zero.
The
StringIO
object can accept either Unicode or 8-bit strings, but mixing the two may take some care. If both are used, 8-bit strings that cannot be interpreted as 7-bit ASCII (that use the 8th bit) will cause a
UnicodeError
to be raised when
getvalue()
被调用。
下列方法对于
StringIO
objects require special mention:
StringIO.
getvalue
(
)
¶
Retrieve the entire contents of the “file” at any time before the
StringIO
对象的
close()
method is called. See the note above for information about mixing Unicode and 8-bit strings; such mixing can cause this method to raise
UnicodeError
.
StringIO.
close
(
)
¶
Free the memory buffer. Attempting to do further operations with a closed
StringIO
object will raise a
ValueError
.
用法范例：
import StringIO output = StringIO.StringIO() output.write('First line.\n') print >>output, 'Second line.' # Retrieve file contents -- this will be # 'First line.\nSecond line.\n' contents = output.getvalue() # Close object and discard memory buffer -- # .getvalue() will now raise an exception. output.close()
cStringIO
— 更快版本的
StringIO
¶
模块
cStringIO
provides an interface similar to that of the
StringIO
module. Heavy use of
StringIO.StringIO
objects can be made more efficient by using the function
StringIO()
from this module instead.
cStringIO.
StringIO
(
[
s
]
)
¶
Return a StringIO-like stream for reading or writing.
Since this is a factory function which returns objects of built-in types, there’s no way to build your own version using subclassing. It’s not possible to set attributes on it. Use the original
StringIO
module in those cases.
不像
StringIO
module, this module is not able to accept Unicode strings that cannot be encoded as plain ASCII strings.
Another difference from the
StringIO
module is that calling
StringIO()
with a string parameter creates a read-only object. Unlike an object created without a string parameter, it does not have write methods. These objects are not generally visible. They turn up in tracebacks as
StringI
and
StringO
.
The following data objects are provided as well:
cStringIO.
InputType
¶
The type object of the objects created by calling
StringIO()
with a string parameter.
cStringIO.
OutputType
¶
The type object of the objects returned by calling
StringIO()
with no parameters.
There is a C API to the module as well; refer to the module source for more information.
用法范例：
import cStringIO output = cStringIO.StringIO() output.write('First line.\n') print >>output, 'Second line.' # Retrieve file contents -- this will be # 'First line.\nSecond line.\n' contents = output.getvalue() # Close object and discard memory buffer -- # .getvalue() will now raise an exception. output.close()