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Python - abs vs fabs
...(-2))
Out[7]: int
In [8]: type(abs(-2.0))
Out[8]: float
In [9]: type(abs(3+4j))
Out[9]: float
In [10]: type(math.fabs(-2))
Out[10]: float
In [11]: type(math.fabs(-2.0))
Out[11]: float
In [12]: type(math.fabs(3+4j))
---------------------------------------------------------------------------
Type...
Python multiprocessing pool.map for multiple arguments
...
388
The answer to this is version- and situation-dependent. The most general answer for recent ver...
Immutable vs Mutable types
...
233
What? Floats are immutable? But can't I do
x = 5.0
x += 7.0
print x # 12.0
Doesn't that "mut...
Swapping column values in MySQL
...t. This method doesn't swap the values if one of them is NULL. Use method #3 that doesn't have this limitation.
UPDATE swap_test SET x=y, y=@temp WHERE (@temp:=x) IS NOT NULL;
This method was offered by Dipin in, yet again, the comments of http://beerpla.net/2009/02/17/swapping-column-values-in-mys...
What's the difference between lists enclosed by square brackets and parentheses in Python?
...you can change its contents:
>>> x = [1,2]
>>> x.append(3)
>>> x
[1, 2, 3]
while tuples are not:
>>> x = (1,2)
>>> x
(1, 2)
>>> x.append(3)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: '...
Algorithm for Determining Tic Tac Toe Game Over
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133
You know a winning move can only happen after X or O has made their most recent move, so you ca...
Does Python have an ordered set?
...ferred to from the Python 2 Documentation. This runs on Py2.6 or later and 3.0 or later without any modifications. The interface is almost exactly the same as a normal set, except that initialisation should be done with a list.
OrderedSet([1, 2, 3])
This is a MutableSet, so the signature for .uni...
Uninitialized constant ActiveSupport::Dependencies::Mutex (NameError)
...
137
This is an incompatibility between Rails 2.3.8 and recent versions of RubyGems. Upgrade to the ...
What is the bower (and npm) version syntax?
...
342
In a nutshell, the syntax for Bower version numbers (and NPM's) is called SemVer, which is sho...
How to get row from R data.frame
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130
x[r,]
where r is the row you're interested in. Try this, for example:
#Add your data
x <...