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Replacing all non-alphanumeric characters with empty strings
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Use [^A-Za-z0-9].
Note: removed the space since that is not typically considered alphanumeric.
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Nullable Foreign Key bad practice?
... read.
Only if you know better than Chris Date "what first normal form really means". If x and y are both nullable, and indeed in some row x and y are both null, then WHERE x=y does not yield true. This proves beyond reasonable doubt that null is not a value (because any real value is always equ...
Changes in import statement python3
...a single function. In Python 2 you were permitted to be semi-lazy:
def sin_degrees(x):
from math import *
return sin(degrees(x))
Note that it already triggers a warning in Python 2:
a.py:1: SyntaxWarning: import * only allowed at module level
def sin_degrees(x):
In modern Python 2 co...
Haskell Type vs Data Constructor
...erstanding type constructors and data constructors. For example, I don't really understand the difference between this:
6 A...
Save bitmap to location
...my image in canvas it is very small. any reason?
– AZ_
Mar 18 '11 at 13:24
3
@Aizaz This will not...
What does the “@” symbol mean in reference to lists in Haskell?
...hout the @, you'd have to choose between (1) or (2):(3).
This syntax actually works for any constructor; if you have data Tree a = Tree a [Tree a], then t@(Tree _ kids) gives you access to both the tree and its children.
s...
How to read environment variables in Scala
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I would also prefer Properties. It allows to retrieve Optionals, and has names for commonly used properties.
– ppopoff
Dec 17 '15 at 14:46
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Adding Only Untracked Files
...where I've interactively added some updates to the index and I want to add all of the untracked files to that index before I commit.
...
Array include any value from another array?
....include?(food) }
=> true
Benchmark script:
require "benchmark"
N = 1_000_000
puts "ruby version: #{RUBY_VERSION}"
CHEESES = %w(chedder stilton brie mozzarella feta haloumi).freeze
FOODS = %w(pizza feta foods bread biscuits yoghurt bacon).freeze
Benchmark.bm(15) do |b|
b.report("&, emp...
Determine Whether Two Date Ranges Overlap
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Proof:
Let ConditionA Mean that DateRange A Completely After DateRange B
_ |---- DateRange A ------|
|---Date Range B -----| _
(True if StartA > EndB)
Let ConditionB Mean that DateRange A is Completely Before DateRange B
|---- DateRange A ...