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What __init__ and self do on Python?
...
In this code:
class A(object):
def __init__(self):
self.x = 'Hello'
def method_a(self, foo):
print self.x + ' ' + foo
... the self variable represents the instance of the object itself. Most object-oriented languages pass this as a hidd...
Does python have an equivalent to Java Class.forName()?
...honic way of doing it.
Here's a function that does what you want:
def get_class( kls ):
parts = kls.split('.')
module = ".".join(parts[:-1])
m = __import__( module )
for comp in parts[1:]:
m = getattr(m, comp)
return m
You can use the return value of this ...
Scala how can I count the number of occurrences in a list
...", "banana", "apple", "oranges", "oranges")
s.groupBy(identity).mapValues(_.size)
giving a Map with a count for each item in the original sequence:
Map(banana -> 1, oranges -> 3, apple -> 3)
The question asks how to find the count of a specific item. With this approach, the solution w...
廉价共享存储解决方案2-drbd+cman+gfs2 - 更多技术 - 清泛网 - 专注C/C++及内核技术
... localhost.localdomain localhost6 localhost6.localdomain6
172.16.20.45 gfs_1
172.16.20.46 gfs_2
10.10.10.45 gfs_1
10.10.10.46 gfs_2
2、配置双机互信
[root@gfs_1 ~]# ssh-keygen -t rsa -P ''
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_r...
List all indexes on ElasticSearch server?
...ise list of all indices in your cluster, call
curl http://localhost:9200/_aliases
this will give you a list of indices and their aliases.
If you want it pretty-printed, add pretty=true:
curl http://localhost:9200/_aliases?pretty=true
The result will look something like this, if your indices ...
Removing multiple keys from a dictionary safely
...
Why not like this:
entries = ('a', 'b', 'c')
the_dict = {'b': 'foo'}
def entries_to_remove(entries, the_dict):
for key in entries:
if key in the_dict:
del the_dict[key]
A more compact version was provided by mattbornski using dict.pop()
...
Check if something is (not) in a list in Python
... @nightcracker That makes no sense as A not in B is reduced to doing not B.__contains__(A) which is the same as what not A in B is reduced to which is not B.__contains__(A).
– Dan D.
May 2 '12 at 0:33
...
pythonic way to do something N times without an index variable?
...ghtly faster approach than looping on xrange(N) is:
import itertools
for _ in itertools.repeat(None, N):
do_something()
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Why is “if not someobj:” better than “if someobj == None:” in Python?
...r not ? This is done using the following algorithm :
If the object has a __nonzero__ special method (as do numeric built-ins, int and float), it calls this method. It must either return a bool value which is then directly used, or an int value that is considered False if equal to zero.
Otherwise, ...
How do JavaScript closures work?
...ing
In the following code, function onClick closes over variable BACKGROUND_COLOR.
const $ = document.querySelector.bind(document)
const BACKGROUND_COLOR = 'rgba(200,200,242,1)'
function onClick() {
$('body').style.background = BACKGROUND_COLOR
}
$('button').addEventListener('click', onClick...
