tan-yuki tan-yuki

振り返り

import Data.List

numUniques :: (Eq a) => [a] -> Int
numUniques = length . nub

infixr 5 ++ -- infixr: 結合度
(++) :: [a] -> [a] -> [a]
[]     ++ ys = ys
(x:xs) ++ ys = x : (xs ++ ys)

下記がインストール済み

nvmのインストールの仕方くらいは自分で調べてね☆

map' :: (a -> b) -> [a] -> [b]
map' f xs = foldr (\x acc -> f x : acc) [] xs
-- acc
-- []
-- [6]

復習) 型と型クラス

Prelude> :t sum
sum :: Num a => [a] -> a
       ^^^
       型クラス

	String.prototype.toSnakeCase = function() {
	var upperChars = this.match(/([A-Z])/g);
	if (! upperChars) {
	return this;
	}

	var str = this.toString();
	for (var i = 0, n = upperChars.length; i < n; i++) {
	str = str.replace(new RegExp(upperChars[i]), '_' + upperChars[i].toLowerCase());
	}

	/**
	* Sanitizing string value.
	*
	* @require jQuery
	*/
	(function($) {
	var $div = $('<div/>');
	String.prototype.sanitize = function() {
	return $div.text(this)[0].innerHTML;
	};

	_.mixin({
	sum: function(list, callback) {
	return _.reduce(list, function(memo, item) {
	return memo + callback(item);
	}, 0);
	}
	});

	// == test ==
	// _.sum([{price:10}, {price:20}, {price:30}], function(item) { return item.price; });