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List comprehension: Returning two (or more) items for each item
...bda x: x + 2
>>> g = lambda x: x ** 2
>>> list(chain.from_iterable((f(x), g(x)) for x in range(3)))
[2, 0, 3, 1, 4, 4]
Timings:
from timeit import timeit
f = lambda x: x + 2
g = lambda x: x ** 2
def fg(x):
yield f(x)
yield g(x)
print timeit(stmt='list(chain.from_itera...
How to create a MySQL hierarchical recursive query
... parent_id
from products
where parent_id = 19
union all
select p.id,
p.name,
p.parent_id
from products p
inner join cte
on p.parent_id = cte.id
)
select * from cte;
The value specified in parent_id = 19 should be set to the...
Python date string to date object
...<stdin>", line 1, in <module>
File "/usr/local/lib/python2.7/_strptime.py", line 308, in _strptime
format_regex = _TimeRE_cache.compile(format)
File "/usr/local/lib/python2.7/_strptime.py", line 265, in compile
return re_compile(self.pattern(format), IGNORECASE)
File "/usr/...
Select columns from result set of stored procedure
...
Here's a link to a pretty good document explaining all the different ways to solve your problem (although a lot of them can't be used since you can't modify the existing stored procedure.)
How to Share Data Between Stored Procedures
Gulzar's answer will work (it is document...
Undoing a 'git push'
... highly dangerous if you are working in a shared repo. As a best practice, all commits pushed to a remote repo that is shared should be considered 'immutable'. Use 'git revert' instead: kernel.org/pub/software/scm/git/docs/…
– Saboosh
Jan 13 '12 at 20:47
...
Performance surprise with “as” and nullable types
...lable types, and I'm adding a section about using the "as" operator, which allows you to write:
10 Answers
...
iphone Core Data Unresolved error while saving
...conflict with the old model implementation.
Edit:
I almost forgot here's all the error codes that Core Data spits out:
Core Data Constants Reference
I had trouble with this before and I realised I unchecked the correct optional box. Such trouble finding out the problem. Good luck.
...
What is the best way to find the users home directory in Java?
... variants. I am looking for a snippet of code that can accomplish this for all platforms, and a way to detect the platform.
...
YouTube API to fetch all videos on a channel
...rly because it only spends 2 quota points instead of 100 (that the search call would spend).
– JP de la Torre
Nov 12 '16 at 10:28
1
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What does it mean for a data structure to be “intrusive”?
...to know about the list it is in, and inform it of changes.
ORM-systems usually revolve around intrusive data structures, to minimize iteration over large lists of objects. For instance, if you retrieve a list of all the employees in the database, then change the name of one of them, and want to sav...