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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: '...
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...
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...
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...
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...
How do I compare two hashes?
...
163
You can compare hashes directly for equality:
hash1 = {'a' => 1, 'b' => 2}
hash2 = {'a' =...
Uninitialized constant ActiveSupport::Dependencies::Mutex (NameError)
...
137
This is an incompatibility between Rails 2.3.8 and recent versions of RubyGems. Upgrade to the ...
pandas GroupBy columns with NaN (missing) values
...
138
This is mentioned in the Missing Data section of the docs:
NA groups in GroupBy are automatica...
What is the difference between Ruby 1.8 and Ruby 1.9
...
Array.to_s Now Contains Punctuation
Ruby 1.9
irb(main):001:0> [1,2,3].to_s
=> "[1, 2, 3]"
Ruby 1.8.6
irb(main):001:0> [1,2,3].to_s
=> "123"
Action: Use .join instead
Colon No Longer Valid In When Statements
Ruby 1.9
irb(main):001:0> case 'a'; when /\w/: puts 'word'; end...
Reverse Range in Swift
...
Update For latest Swift 3 (still works in Swift 4)
You can use the reversed() method on a range
for i in (1...5).reversed() { print(i) } // 5 4 3 2 1
Or stride(from:through:by:) method
for i in stride(from:5,through:1,by:-1) { print(i) } // 5 4...