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Why is NaN not equal to NaN? [duplicate]
The relevant IEEE standard defines a numeric constant NaN (not a number) and prescribes that NaN should compare as not equal to itself. Why is that?
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What is the difference between the GNU Makefile variable assignments =, ?=, := and +=?
Can anybody give a clear explanation of how variable assignment really works in Makefiles.
6 Answers
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If a DOM Element is removed, are its listeners also removed from memory?
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Modern browsers
Plain JavaScript
If a DOM element which is removed is reference-free (no references pointing to it) then yes - the element itself is picked up by the garbage collector as well as any event handlers/listeners associ...
How do I split a string so I can access item x?
...|8765'
Declare @individual varchar(20) = null
WHILE LEN(@products) > 0
BEGIN
IF PATINDEX('%|%', @products) > 0
BEGIN
SET @individual = SUBSTRING(@products,
0,
PATINDEX('%|%', @products))
SELECT @in...
.append(), prepend(), .after() and .before()
I am pretty proficient with coding, but now and then I come across code that seems to do basically the same thing. My main question here is, why would you use .append() rather then .after() or vice verses?
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Access nested dictionary items via a list of keys?
...to traverse the dictionary:
from functools import reduce # forward compatibility for Python 3
import operator
def getFromDict(dataDict, mapList):
return reduce(operator.getitem, mapList, dataDict)
and reuse getFromDict to find the location to store the value for setInDict():
def setInDict(dat...
Convert base class to derived class [duplicate]
Is it possible in C# to explicitly convert a base class object to one of it's derived classes? Currently thinking I have to create a constructor for my derived classes that accept a base class object as a parameter and copy over the property values. I don't really like this idea, so I'd like to avoi...
How do you set, clear, and toggle a single bit?
How do you set, clear, and toggle a bit?
30 Answers
30
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Mysql: Select rows from a table that are not in another
How to select all rows in one table that do not appear on another?
8 Answers
8
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Strange, unexpected behavior (disappearing/changing values) when using Hash default value, e.g. Hash
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First, note that this behavior applies to any default value that is subsequently mutated (e.g. hashes and strings), not just arrays.
TL;DR: Use Hash.new { |h, k| h[k] = [] } if you want the most idiomatic solution and don’t care why.
What do...