python - Why is __repr__ called in the code below? -


can please me why __repr__ method called q.pop() method in code below?

>>> class item: ...     def __init__(self, name): ...         self.name = name ...     def __repr__(self): ...         return 'item({!r})'.format(self.name) ... >>> q = priorityqueue() >>> q.push(item('foo'), 1) >>> q.push(item('bar'), 5) >>> q.push(item('spam'), 4) >>> q.push(item('grok'), 1) >>> q.pop() item('bar') >>> q.pop() item('spam') >>> q.pop() item('foo') >>> q.pop() item('grok')  >>>

the built-in __repr__ function used return printable format of object. in case, because item custom object/class, override in __repr__ allows instance of item displayed in terminal. see when call q.pop(), item printed screen, , printing done through override of __repr__ function.

q.pop() prints item('bar')because overridden __repr__ function item says print 'item({!r})'.format(self.name). prints word: item('') , format part fills in actual contents of item between single quotes, resulting in item('bar') being printed screen.

read more here: purpose of python's __repr__


Comments

Post a Comment

Popular posts from this blog

php - Vagrant up error - Uncaught Reflection Exception: Class DOMDocument does not exist -

i've set bento/ubuntu-16.04 vagrant box using php 5.6, , getting following error quite few times when try , run shell script: "uncaught reflection exception: class domdocument not exist". i've tried adding following top of script (not together), each no success: "sudo apt-get install php5.6-xml", "sudo apt-get install php5-xml", "sudo apt-get install php-dom" i've tried resetting server "sudo service apache2 restart". does have suggestions?
Read more

vue.js - Create hooks for automated testing -

Image
qa guys complained can't automate frontend testing. because our html looks same outside. lazy hack did this <template> <div :role="$options.name"> ... </div> </template> <script> export default { name: 'vmcomponentname' } </script> which takes name script , applies html. in browser get: <div role="vmcomponentname"> ... </div> line :role="$options.name" goes in every component. is there dry er solutions? please share. additional details i'll explain in details looking for. imagine have vmusercreate form creates user. test case can create user . to automatically test without role, have use following selector: .wrapper > .wrapper > .wrapper > .submit-button the test extremely brittle (will break lot). if use roles can use [role="vmusercreateform"] .submit-button selector. many folds less brittle. so basically, i'm ...
Read more

Add new key value to json node in java -

i have json file : { "id":1, "name":"abc", "addressdetails": { "city":"newyork" } } i wanted add 1 more key-value ("pincode" : "414141") node 'addressdetails'. i tried using : objectmapper mapper = new objectmapper(); jsonnode root = mapper.readtree(new file("d://test.json")); objectnode node = mapper.createobjectnode(); node.with("addressdetails").put("pincode", "414141"); but it's not getting added, there way can ? you can try you should modify file path objectmapper mapper = new objectmapper(); objectnode nodes = mapper.readvalue(new file("d:\\test.txt"), objectnode.class); nodes.with("addressdetails").put("pincode", "414141"); mapper.writer().writevalue(new file("d:\\test.txt"), nodes);
Read more