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MySQL indexes - what are the best practices?
...or selecting using a WHERE clause but sometimes it doesn't seem so black and white.
7 Answers
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Django admin: how to sort by one of the custom list_display fields that has no database field
...ustom manager for Customer which includes the number of orders aggregated, and then setting admin_order_field to that aggregate, ie
from django.db import models
class CustomerManager(models.Manager):
def get_query_set(self):
return super(CustomerManager, self).get_query_set().annotat...
What's the fastest way to loop through an array in JavaScript?
...dern browsers:
https://jsben.ch/wY5fo
Currently, the fastest form of loop (and in my opinion the most syntactically obvious).
A standard for-loop with length caching
var i = 0, len = myArray.length;
while (i < len) {
// your code
i++
}
I would say, this is definitely ...
How does zip(*[iter(s)]*n) work in Python?
...unction call. Therefore you're passing the same iterator 3 times to zip(), and it pulls an item from the iterator each time.
x = iter([1,2,3,4,5,6,7,8,9])
print zip(x, x, x)
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Should I use static_cast or reinterpret_cast when casting a void* to whatever
Both static_cast and reinterpret_cast seem to work fine for casting void* to another pointer type. Is there a good reason to favor one over the other?
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Does async(launch::async) in C++11 make thread pools obsolete for avoiding expensive thread creation
...rong. I was under the impression that Linux thread creation was very cheap and after testing I determined that the overhead of function call in a new thread vs. a normal one is enormous. The overhead for creating a thread to handle a function call is something like 10000 or more times slower than a ...
Script parameters in Bash
...arguments that you provide to a bashscript will appear in the variables $1 and $2 and $3 where the number refers to the argument. $0 is the command itself.
The arguments are seperated by spaces, so if you would provide the -from and -to in the command, they will end up in these variables too, so fo...
Process all arguments except the first one (in a bash script)
...ave a simple script where the first argument is reserved for the filename, and all other optional arguments should be passed to other parts of the script.
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String.IsNullOrWhiteSpace in LINQ Expression
...NOT (([t0].[Diameter] IS NULL) OR (LTRIM(RTRIM([t0].[Diameter])) = @p0))
and for Linq to SQL almost but not quite the same
DECLARE @p0 NVarChar(1000) = ''
...
WHERE NOT (LTRIM(RTRIM([t0].[TypeName])) = @p0)
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Sorting Python list based on the length of the string
... such that cmp(x, y) returns -1 if x is less than y, 0 if x is equal to y, and 1 if x is greater than y.
Of course, you can instead use the key parameter:
xs.sort(key=lambda s: len(s))
This tells the sort method to order based on whatever the key function returns.
EDIT: Thanks to balpha and Ruslan ...