Print instance of class python
When I try to Show
How can I can define the printing behaviour (or the string representation) of a class and its instances? For example, referring to the above code, how can I modify the
asked Oct 8, 2009 at 2:35
Ashwin NanjappaAshwin Nanjappa 73.5k78 gold badges206 silver badges291 bronze badges 0
The If no
answered Oct 8, 2009 at 2:39
Chris LutzChris Lutz 71k16 gold badges125 silver badges182 bronze badges 7 As Chris Lutz explains, this is defined by the From the documentation of
Given the following class Test:
..it will act the following way in the Python shell:
If no If no
answered Oct 8, 2009 at 2:55
7 A generic way that can be applied to any class without specific formatting could be done as follows:
And then,
produces
answered Sep 17, 2015 at 16:35
user394430user394430 2,6052 gold badges25 silver badges27 bronze badges 0 If you're in a situation like @Keith you could try:
It goes against what I would consider good style but if you're just trying to debug then it should do what you want. answered Oct 25, 2018 at 22:25
JohnJohn 1,5397 silver badges11 bronze badges 4 A prettier version of response by @user394430
Produces visually nice list of the names and values.
An even fancier version (thanks Ruud) sorts the items:
answered Mar 14, 2018 at 15:44
1 For Python 3: If the specific format isn't important (e.g. for debugging) just inherit from the Printable class below. No need to write code for every object. Inspired by this answer
answered May 20, 2016 at 14:26
PeterMPeterM 2,16224 silver badges35 bronze badges 1 Just to add my two cents to @dbr's answer, following is an example of how to implement this sentence from the official documentation he's cited:
Given this class definition:
Now, is easy to serialize
instance of
So, running last piece of code, we'll get:
But, as I said in my last comment: more info is just here!
answered Dec 20, 2012 at 11:27
tnotstartnotstar 1,3011 gold badge15 silver badges25 bronze badges Simple. In the print, do:
as long as the constructor is
answered Jan 27, 2021 at 17:01
AlonAlon 1511 silver badge7 bronze badges 1 You need to use
Robᵩ 157k17 gold badges224 silver badges300 bronze badges answered Jan 16, 2013 at 9:04
flow_chartflow_chart 1551 silver badge4 bronze badges 1
The output is like
answered Mar 13, 2021 at 0:59
minkerminker 3523 silver badges3 bronze badges There are already a lot of answers in this thread but none of them particularly helped me, I had to work it out myself, so I hope this one is a little more informative. You just have to make sure you have parentheses at the end of your class, e.g:
Here's an example of code from a project I was working on:
To print my Hydrogen class, I used the following:
Please note, this will not work without the parentheses at the end of Hydrogen. They are necessary. Hope this helps, let me know if you have anymore questions. answered Aug 4, 2015 at 4:52
Even though this is an older post, there is also a very convenient method introduced in dataclasses (as of Python 3.7). Besides other special functions such as
If you want to
hide a certain attribute from being outputted, you can set the field decorator parameter
answered Aug 24 at 14:54
dheinzdheinz 7848 silver badges14 bronze badges Not the answer you're looking for? Browse other questions tagged python class printing object or ask your own question.How do you print an instance of a class in Python?Print an Object in Python Using the __repr__() Method
It, by default, returns the name of the object's class and the address of the object. When we print an object in Python using the print() function, the object's __str__() method is called.
How do I print all instances of a class?To print all instances of a class with Python, we can use the gc module. We have the A class and we create 2 instances of it, which we assigned to a1 and a2 . Then we loop through the objects in memory with gc. get_objects with a for loop.
How do I find my instance of Python?Using isinstance() function, we can test whether an object/variable is an instance of the specified type or class such as int or list. In the case of inheritance, we can checks if the specified class is the parent class of an object. For example, isinstance(x, int) to check if x is an instance of a class int .
What is the __ str __ method in Python?Python __str__()
This method returns the string representation of the object. This method is called when print() or str() function is invoked on an object. This method must return the String object.
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