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List comprehension on a nested list?
... Super useful! Makes it clear that loops (top-to-bottom) are ordered left to right in the generator. This not obvious since in (f(x) for x in l) places the second line of the for-loop equivalent on the left.
– user48956
Jan 11 '18 at 18:11
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How to avoid long nesting of asynchronous functions in Node.js
... look at flow-js, step and async and it seems that they only deal with the order of function execution. In my case there is access to inline closure variables in every indentation. So for example the functions work like this: get HTTP req/res, get userid from DB for cookie, get email for the later u...
When should iteritems() be used instead of items()?
... more like a set (which you'd expect from a dict).
Simple example:
common_keys = list(dict_a.viewkeys() & dict_b.viewkeys())
Will give you a list of the common keys, but again, in Python 3.x - just use .keys() instead.
Python 3.x has generally been made to be more "lazy" - i.e. map is now e...
Get last result in interactive Python shell
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Underscore.
>>> 5+5
10
>>> _
10
>>> _ + 5
15
>>> _
15
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How can I add reflection to a C++ application?
...re are some handy macros to help with typed expressions:
#define REM(...) __VA_ARGS__
#define EAT(...)
// Retrieve the type
#define TYPEOF(x) DETAIL_TYPEOF(DETAIL_TYPEOF_PROBE x,)
#define DETAIL_TYPEOF(...) DETAIL_TYPEOF_HEAD(__VA_ARGS__)
#define DETAIL_TYPEOF_HEAD(x, ...) REM x
#define DETAIL_TYP...
Javascript replace with reference to matched group?
I have a string, such as hello _there_ . I'd like to replace the two underscores with <div> and </div> respectively, using JavaScript . The output would (therefore) look like hello <div>there</div> . The string might contain multiple pairs of underscores.
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Repeat string to certain length
...
def repeat_to_length(string_to_expand, length):
return (string_to_expand * ((length/len(string_to_expand))+1))[:length]
For python3:
def repeat_to_length(string_to_expand, length):
return (string_to_expand * (int(length/len(s...
Bootstrap 3: pull-right for col-lg only
...to create your own class with media queries. Bootstrap 3 already has float ordering for media breakpoints under Column Ordering: http://getbootstrap.com/css/#grid-column-ordering
The syntax for the class is col-<#grid-size>-(push|pull)-<#cols> where <#grid-size> is xs, sm, md or l...
Django ManyToMany filter()
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Just restating what Tomasz said.
There are many examples of FOO__in=... style filters in the many-to-many and many-to-one tests. Here is syntax for your specific problem:
users_in_1zone = User.objects.filter(zones__id=<id1>)
# same thing but using in
users_in_1zone = User.object...
What's the difference between django OneToOneField and ForeignKey?
...)
>>> e2 = Engine2.objects.get(name='Wankel')
>>> e2.car2_set.all()
[<Car2: Mazda>]
Model Code
from django.db import models
class Engine(models.Model):
name = models.CharField(max_length=25)
def __unicode__(self):
return self.name
class Car(models.Model)...