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Python __call__ special method practical example
I know that __call__ method in a class is triggered when the instance of a class is called. However, I have no idea when I can use this special method, because one can simply create a new method and perform the same operation done in __call__ method and instead of calling the instance, you can c...
Explaining Python's '__enter__' and '__exit__'
...
Using these magic methods (__enter__, __exit__) allows you to implement objects which can be used easily with the with statement.
The idea is that it makes it easy to build code which needs some 'cleandown' code executed (think of it as a try-finally...
Delete column from pandas DataFrame
...
As you've guessed, the right syntax is
del df['column_name']
It's difficult to make del df.column_name work simply as the result of syntactic limitations in Python. del df[name] gets translated to df.__delitem__(name) under the covers by Python.
...
Stop Mongoose from creating _id property for sub-document array items
...ose");
var subSchema = mongoose.Schema({
//your subschema content
},{ _id : false });
var schema = mongoose.Schema({
// schema content
subSchemaCollection : [subSchema]
});
var model = mongoose.model('tablename', schema);
...
Best practices for circular shift (rotate) operations in C++
... it to rotate by the width of the type (using fixed-width types like uint32_t).
#include <stdint.h> // for uint32_t
#include <limits.h> // for CHAR_BIT
// #define NDEBUG
#include <assert.h>
static inline uint32_t rotl32 (uint32_t n, unsigned int c)
{
const unsigned int mask...
How to read data From *.CSV file using javascript?
... newlines:
data.txt:
heading1,heading2,heading3,heading4,heading5,value1_1,...,value5_2
javascript:
$(document).ready(function() {
$.ajax({
type: "GET",
url: "data.txt",
dataType: "text",
success: function(data) {processData(data);}
});
});
function pr...
Is False == 0 and True == 1 an implementation detail or is it guaranteed by the language?
..., because list indexing only works with integers, or objects that define a __index__ method (thanks mark-dickinson).
Edit:
It is true of the current python version, and of that of Python 3. The docs for python 2.6 and the docs for Python 3 both say:
There are two types of integers: [...] Integ...
When to use Comparable and Comparator
... | Comparable | Comparator
._______________________________________________________________________________
Is used to allow Collections.sort to work | yes | yes
Can compare multiple fields | yes ...
Using property() on classmethods
...te the property on the metaclass.
>>> class foo(object):
... _var = 5
... class __metaclass__(type): # Python 2 syntax for metaclasses
... pass
... @classmethod
... def getvar(cls):
... return cls._var
... @classmethod
... def setvar(cls, value):
.....
What's a correct and good way to implement __hash__()?
What's a correct and good way to implement __hash__() ?
6 Answers
6
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