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Django select only rows with duplicate field values
... syntax is also how Django interprets you wanting to do a join. So, essentially when you try to filter on that, Django thinks you're trying to do a join with count which obviously doesn't exist. The fix is to specify a name for your annotation result, i.e. annotate(mycount=Count('id')) and then filt...
How to avoid circular imports in Python? [duplicate]
....py
Types of circular import problems
Circular import dependencies typically fall into two categories depending
on what you're trying to import and where you're using it inside each
module. (And whether you're using python 2 or 3).
1. Errors importing modules with circular imports
In some cases...
What is the most efficient string concatenation method in python?
... idiomatic and thus easier for other python programmers to understand.
Finally, the golden rule of optimization: don't optimize unless you know you need to, and measure rather than guessing.
You can measure different methods using the timeit module. That can tell you which is fastest, instead of r...
Printf width specifier to maintain precision of floating-point value
...ier which can be applied to a floating point specifier that would automatically format the output to the necessary number of significant digits such that when scanning the string back in, the original floating point value is acquired?
...
How to fix “Attempted relative import in non-package” even with __init__.py
...ry to execute the above shell command, the fact that you need __init__.pys all the way down, and the __package__-modifying trickery (described below by BrenBarn) needed to allow these imports for executable scripts (e.g. when using a shebang and doing ./my_script.py at the Unix shell) would all be u...
What's the bad magic number error?
...the pyc file or trying to run a pyc from a different version of python (usually later) than your interpreter.
If they are your pyc files, just delete them and let the interpreter re-compile the py files. On UNIX type systems, that could be something as simple as:
rm *.pyc
or:
find . -name '*.py...
Installing Google Protocol Buffers on mac
I would like to install the older version of Google Protocol Buffers (protobuf-2.4.1) on mac using Terminal command line. I tried with brew install protobuf , but the latest version 2.5.0 has been installed. Is it possible to install the older version from terminal.
...
Underscore: sortBy() based on multiple attributes
... said, that's pretty hacky. To do this properly you'd probably want to actually use the core JavaScript sort method:
patients.sort(function(x, y) {
var roomX = x[0].roomNumber;
var roomY = y[0].roomNumber;
if (roomX !== roomY) {
return compare(roomX, roomY);
}
return compare(x[0].name...
Is 'switch' faster than 'if'?
Is a switch statement actually faster than an if statement?
12 Answers
12
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Why does the expression 0 < 0 == 0 return False in Python?
...o say 0 &lt; x &lt;= 5 than to say (0 &lt; x) and (x &lt;= 5).
These are called chained comparisons. And that's a link to the documentation for them.
With the other cases you talk about, the parenthesis force one relational operator to be applied before the other, and so they are no longer chained...