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Haskell Type vs Data Constructor
...erstanding type constructors and data constructors. For example, I don't really understand the difference between this:
6 A...
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
...
I would also prefer Properties. It allows to retrieve Optionals, and has names for commonly used properties.
– ppopoff
Dec 17 '15 at 14:46
...
Determine Whether Two Date Ranges Overlap
...
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 ...
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...
Configuring so that pip install can work from github
...oo would be:
foo # the installable package
├── foo
│ ├── __init__.py
│ └── bar.py
└── setup.py
And install from github like:
$ pip install git+ssh://git@github.com/myuser/foo.git
or
$ pip install git+https://github.com/myuser/foo.git@v123
or
$ pip install git+htt...
Combine --user with --prefix error with setup.py install
...me workaround:
pip install --user --install-option="--prefix=" <package_name>
or
python setup.py install --user --prefix=
Note that there is no text (not even whitespace) after the =.
Do not forget the --user flag.
Installing multiple packages:
Create ~/.pydistutils.cfg (or equivalent...
Using multiple delimiters in awk
...n the input field separator.
See another example:
$ cat file
hello#how_are_you
i#am_very#well_thank#you
This file has two fields separators, # and _. If we want to print the second field regardless of the separator being one or the other, let's make both be separators!
$ awk -F"#|_" '{print ...
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.
...
reference assignment is atomic so why is Interlocked.Exchange(ref Object, Object) needed?
In my multithreaded asmx web service I had a class field _allData of my own type SystemData which consists of few List<T> and Dictionary<T> marked as volatile . The system data ( _allData ) is refreshed once in a while and I do it by creating another object called newData and fill...