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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...
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...
enum - getting value of enum on string conversion
...;>> member.name
'red'
>>> member.value
1
You could add a __str__ method to your enum, if all you wanted was to provide a custom string representation:
class D(Enum):
def __str__(self):
return str(self.value)
x = 1
y = 2
Demo:
>>> from enum import E...
代码块超过1.2w编译apk报错问题 - App Inventor 2 中文网 - 清泛IT社区，为创新赋能！
...ng.api.ApiProxy$RequestTooLargeException: The request to API call datastore_v3.Put() was too large.
at com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure(RPC.java:416)
at com.google.gwt.user.server.rpc.RPC.invokeAnd...
Get Root Directory Path of a PHP project
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For PHP >= 5.3.0 try
PHP magic constants.
__DIR__
And make your path relative.
For PHP < 5.3.0 try
dirname(__FILE__)
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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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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...
When to use Comparable and Comparator
... | Comparable | Comparator
._______________________________________________________________________________
Is used to allow Collections.sort to work | yes | yes
Can compare multiple fields | yes ...
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...