'Type the name of an object in python interpreter - what method is it called?
What method is it called when I type the name of the object?
I always thought that it was calling either repr
or str
but that doesn't hold in case of the PageObject of PyPDF2. As you can see, the output of __repr__
or __str__
is different to the one we get when we type the name of the variable in the interactive console.
>>> reader = PdfFileReader(f)
>>> page = reader.pages[0]
>>> page
'/Encoding': {'/Differences': [32,
'/space',
40,
'/parenleft',
'/parenright',
46,
'/period',
'/slash',
'/zero',
'/one',
'/two',
'/three',
'/four',
'/five',
'/six',
56,
'/eight',
'/nine',
69,
...
>>> page.__str__()
"{'/Annots': [], '/Contents': IndirectObject(12, 0), '/Group': {'/CS': '/DeviceRGB', '/S': '/Transparency', '/Type': '/Group'}, '/MediaBox': RectangleObject([0, 0, 460.8, 345.6]), '/Parent': IndirectObject(2, 0), '/Resources': IndirectObject(8, 0), '/Type': '/Page', '/ArtBox': RectangleObject([0, 0, 460.8, 345.6]), '/BleedBox': RectangleObject([0, 0, 460.8, 345.6]), '/CropBox': RectangleObject([0, 0, 460.8, 345.6]), '/TrimBox': RectangleObject([0, 0, 460.8, 345.6])}"
```
>>> page.__repr__()
<same-as-above>
P.S. Probably there's an answer out there for this question and it's just that I haven't typed my query correctly.
UPDATE I observe this behavior in IPython (version 5.5.0). Running with the builtin REPL the output I get when typing the variable name matches the repr
output.
Solution 1:[1]
Using a variable name (like x
) in the standard Python REPL is equivalent to print(repr(x))
. You can convince yourself of that (and that it is not simply print(x)
) by implementing __repr__
and __str__
yourself:
>>> class Test:
... def __repr__(self):
... return 'using repr\nmagic, isn\'t it?'
... def __str__(self):
... return 'using str'
...
>>> Test()
using repr
magic, isn't it?
>>> repr(Test())
"using repr\nmagic, isn't it?"
>>> print(Test())
using str
>>> print(repr(Test()))
using repr
magic, isn't it?
But you are using IPython, which features rich outputs; which means that some objects get special treatment when being displayed. Dicts are such objects; and since your page
is a special kind of dict
:
Help on PageObject in module PyPDF2.pdf object:
class PageObject(PyPDF2.generic.DictionaryObject)
| PageObject(pdf=None, indirectRef=None)
|
| This class represents a single page within a PDF file. Typically this
| object will be created by accessing the
| :meth:`getPage()<PyPDF2.PdfFileReader.getPage>` method of the
| :class:`PdfFileReader<PyPDF2.PdfFileReader>` class, but it is
| also possible to create an empty page with the
| :meth:`createBlankPage()<PageObject.createBlankPage>` static method.
|
| :param pdf: PDF file the page belongs to.
| :param indirectRef: Stores the original indirect reference to
| this object in its source PDF
|
| Method resolution order:
| PageObject
| PyPDF2.generic.DictionaryObject
| builtins.dict
| PyPDF2.generic.PdfObject
| builtins.object
[…snip…]
Then you get the special dict
display; which is akin to using pprint.pprint
:
>>> import pprint
>>> from PyPDF2 import PdfFileReader
>>> PDF = PdfFileReader('…')
>>> page = PDF.pages[0]
>>> pprint.pprint(page)
{'/Contents': IndirectObject(2, 0),
'/Group': {'/CS': '/DeviceRGB',
'/I': <PyPDF2.generic.BooleanObject object at 0x7faa67639310>,
'/S': '/Transparency'},
'/MediaBox': [0, 0, 842, 595],
'/Parent': IndirectObject(6, 0),
'/Resources': IndirectObject(23, 0),
'/Rotate': 0,
'/Type': '/Page'}
Sources
This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.
Source: Stack Overflow
Solution | Source |
---|---|
Solution 1 | 301_Moved_Permanently |