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Is there any advantage of using map over unordered_map in case of trivial keys?
A recent talk about unordered_map in C++ made me realize that I should use unordered_map for most cases where I used map before, because of the efficiency of lookup ( amortized O(1) vs. O(log n) ). Most times I use a map, I use either int or std::string as the key type; hence, I've got...
Reusable library to get human readable version of file size?
...came up with a version that avoids loops, using log2 to determine the size order which doubles as a shift and an index into the suffix list:
from math import log2
_suffixes = ['bytes', 'KiB', 'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 'ZiB', 'YiB']
def file_size(size):
# determine binary order in ste...
What optimizations can GHC be expected to perform reliably?
... also explains the passes fairly well. This page explains the optimization ordering, though, like the majority of the Trac Wiki, it is out of date.
For specifics, the best thing to do is probably to look at how a specific program is compiled. The best way to see which optimizations are being perfor...
How to pass anonymous types as parameters?
...passed around, a more structured way may / should normally be preferred in order to not introduce hard to find bugs (you're sidestepping the type system). However, if you want to find a compromise, another way is to simply pass a generic Dictionary. C# dictionary initializers are pretty convenient t...
MySQL INNER JOIN select only one row from second table
... = (
SELECT id
FROM payments AS p2
WHERE p2.user_id = u.id
ORDER BY date DESC
LIMIT 1
)
Or
SELECT u.*, p.*
FROM users AS u
INNER JOIN payments AS p ON p.user_id = u.id
WHERE NOT EXISTS (
SELECT 1
FROM payments AS p2
WHERE
p2.user_id = p.user_id AND
(p...
How to urlencode a querystring in Python?
... not always do the trick. The problem is that some services care about the order of arguments, which gets lost when you create the dictionary. For such cases, urllib.quote_plus is better, as Ricky suggested."
– Blairg23
Aug 17 '15 at 21:35
...
View's SELECT contains a subquery in the FROM clause
...y client_id
create view view_credit_status as
select
credit_orders.client_id,
sum(credit_orders.number_of_credits) as purchased,
ifnull(t1.credits_used,0) as used
from credit_orders
left outer join view_clients_credit_usage as t1 on t1.client_id = credit_ord...
Python Logging (function name, file name, line number) using a single file
...all calls to a single log file or other output target: they will be in the order they occurred in the process.
Next up: (2). locals() provides a dict of the current scope. Thus, in a method that has no other arguments, you have self in scope, which contains a reference to the current instance. The ...
Volatile Vs Atomic [duplicate]
... This is only half the truth, you are missing the very important order-of-execution problem. See my explanation below.
– TwoThe
Nov 2 '13 at 18:05
23
...
When/Why to use Cascading in SQL Server?
...onship can involve an exclusive "is part of" description. For example, an OrderLine record is part of its parent order, and OrderLines will never be shared between multiple orders. If the Order were to vanish, the OrderLine should as well, and a line without an Order would be a problem.
The canonic...