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MeguroLYAHFGG#2（すごいHaskell本を原書で読む会 )のノート。@nnm_techさんがまとめたものに実行結果と補足を追加したものです。
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| { | |
| "cells": [ | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "# An intro to lists" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 1, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[4,8,15,16,23,42]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "let lostNumbers = [4,8,15,16,23,42]\n", | |
| "lostNumbers" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- listは同じ型のデータをもつ\n", | |
| "- \"hello\"`は `['h','e','l','l','o']`のシンタックスシュガー、文字列はlistなので" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 2, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[4,8,15,16,23,42]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "lostNumbers' = [4,8,15,16,23,42]\n", | |
| "lostNumbers'" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "GHC 8からはghciでもletが不要になった。\n", | |
| "\n", | |
| "## リスト演算子" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 3, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[1,2,3,4,9,10,11,12]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "\"hello world\"" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "\"woot\"" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "[1,2,3,4] ++ [9,10,11,12]\n", | |
| "\"hello\" ++ \" \" ++ \"world\"\n", | |
| "['w','o'] ++ ['o','t']" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `++` list結合\n", | |
| " - ２つのリストを結合するとき、Haskellは内部で `++`の左側のリストを走査するので、大きなリストを扱うときは注意" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 4, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "\"ASMALL CAT\"" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[5,1,2,3,4,5]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "'A':\"SMALL CAT\"\n", | |
| "5:[1,2,3,4,5]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `:` 先頭に要素を追加\n", | |
| " - `[1,2,3]`は `1:2:3:[]`のシンタックスシュガー\n", | |
| " \n", | |
| " Note: `[]`, `[[]]`, `[[],[],[]]`は全て異なるものである最初は空リスト、２番目は空リストを含むリスト、最後は3つの空リストを含むリスト" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 5, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "'B'" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "33.2" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "\"Steve Buscemi\" !! 6\n", | |
| "[9.4,33.2,96.2,11.2,23.25] !! 1" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `!!` 特定のindexの要素を取りだす" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 6, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[[1,2,3,4],[5,3,3,3],[1,2,2,3,4],[1,2,3]]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[[1,2,3,4],[5,3,3,3],[1,2,2,3,4],[1,2,3],[1,1,1,1]]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[[6,6,6],[1,2,3,4],[5,3,3,3],[1,2,2,3,4],[1,2,3]]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[1,2,2,3,4]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "let b = [[1,2,3,4],[5,3,3,3],[1,2,2,3,4],[1,2,3]]\n", | |
| "b\n", | |
| "b ++ [[1,1,1,1]] \n", | |
| "[6,6,6]:b\n", | |
| "b !! 2" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- listは入れ子にすることもできる\n", | |
| "- list中に複数のリストを保持するとき、長さが異なってもいいが内包する各リストの型が異なることは許されない" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 7, | |
| "metadata": { | |
| "scrolled": false | |
| }, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "True" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "True" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "True" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "True" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "True" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "[3,2,1] > [2,1,0] \n", | |
| "[3,2,1] > [2,10,100]\n", | |
| "[3,4,2] > [3,4]\n", | |
| "[3,4,2] > [2,4]\n", | |
| "[3,4,2] == [3,4,2]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `<`, `<=`, `>` と `>=` 辞書的な比較\n", | |
| " - 先頭要素を比較していき、もし同じ値の場合次の要素の比較をする\n", | |
| "\n", | |
| "\n", | |
| "## list関数" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 8, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "5" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "head [5,4,3,2,1]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `head` 先頭要素を返す" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 9, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[4,3,2,1]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "tail [5,4,3,2,1]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `tail` 先頭要素以外のリストを返す" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 10, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "1" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "last [5,4,3,2,1]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `last` 末尾要素を返す" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 11, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[5,4,3,2]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "init [5,4,3,2,1]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `init` 末尾要素以外のリストを返す" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 12, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/html": [ | |
| "<style>/* Styles used for the Hoogle display in the pager */\n", | |
| ".hoogle-doc {\n", | |
| "display: block;\n", | |
| "padding-bottom: 1.3em;\n", | |
| "padding-left: 0.4em;\n", | |
| "}\n", | |
| ".hoogle-code {\n", | |
| "display: block;\n", | |
| "font-family: monospace;\n", | |
| "white-space: pre;\n", | |
| "}\n", | |
| ".hoogle-text {\n", | |
| "display: block;\n", | |
| "}\n", | |
| ".hoogle-name {\n", | |
| "color: green;\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".hoogle-head {\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".hoogle-sub {\n", | |
| "display: block;\n", | |
| "margin-left: 0.4em;\n", | |
| "}\n", | |
| ".hoogle-package {\n", | |
| "font-weight: bold;\n", | |
| "font-style: italic;\n", | |
| "}\n", | |
| ".hoogle-module {\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".hoogle-class {\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".get-type {\n", | |
| "color: green;\n", | |
| "font-weight: bold;\n", | |
| "font-family: monospace;\n", | |
| "display: block;\n", | |
| "white-space: pre-wrap;\n", | |
| "}\n", | |
| ".show-type {\n", | |
| "color: green;\n", | |
| "font-weight: bold;\n", | |
| "font-family: monospace;\n", | |
| "margin-left: 1em;\n", | |
| "}\n", | |
| ".mono {\n", | |
| "font-family: monospace;\n", | |
| "display: block;\n", | |
| "}\n", | |
| ".err-msg {\n", | |
| "color: red;\n", | |
| "font-style: italic;\n", | |
| "font-family: monospace;\n", | |
| "white-space: pre;\n", | |
| "display: block;\n", | |
| "}\n", | |
| "#unshowable {\n", | |
| "color: red;\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".err-msg.in.collapse {\n", | |
| "padding-top: 0.7em;\n", | |
| "}\n", | |
| ".highlight-code {\n", | |
| "white-space: pre;\n", | |
| "font-family: monospace;\n", | |
| "}\n", | |
| ".suggestion-warning { \n", | |
| "font-weight: bold;\n", | |
| "color: rgb(200, 130, 0);\n", | |
| "}\n", | |
| ".suggestion-error { \n", | |
| "font-weight: bold;\n", | |
| "color: red;\n", | |
| "}\n", | |
| ".suggestion-name {\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| "</style><span class='err-msg'>Prelude.head: empty list</span>" | |
| ], | |
| "text/plain": [ | |
| "Prelude.head: empty list" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "head []\n", | |
| "tail []\n", | |
| "last []\n", | |
| "init []" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- 上記関数、空リストのときにエラーが起きる点注意" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 13, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "5" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "length [5,4,3,2,1]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `length` リストの長さを返す" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 14, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/html": [ | |
| "<style>/* Styles used for the Hoogle display in the pager */\n", | |
| ".hoogle-doc {\n", | |
| "display: block;\n", | |
| "padding-bottom: 1.3em;\n", | |
| "padding-left: 0.4em;\n", | |
| "}\n", | |
| ".hoogle-code {\n", | |
| "display: block;\n", | |
| "font-family: monospace;\n", | |
| "white-space: pre;\n", | |
| "}\n", | |
| ".hoogle-text {\n", | |
| "display: block;\n", | |
| "}\n", | |
| ".hoogle-name {\n", | |
| "color: green;\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".hoogle-head {\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".hoogle-sub {\n", | |
| "display: block;\n", | |
| "margin-left: 0.4em;\n", | |
| "}\n", | |
| ".hoogle-package {\n", | |
| "font-weight: bold;\n", | |
| "font-style: italic;\n", | |
| "}\n", | |
| ".hoogle-module {\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".hoogle-class {\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".get-type {\n", | |
| "color: green;\n", | |
| "font-weight: bold;\n", | |
| "font-family: monospace;\n", | |
| "display: block;\n", | |
| "white-space: pre-wrap;\n", | |
| "}\n", | |
| ".show-type {\n", | |
| "color: green;\n", | |
| "font-weight: bold;\n", | |
| "font-family: monospace;\n", | |
| "margin-left: 1em;\n", | |
| "}\n", | |
| ".mono {\n", | |
| "font-family: monospace;\n", | |
| "display: block;\n", | |
| "}\n", | |
| ".err-msg {\n", | |
| "color: red;\n", | |
| "font-style: italic;\n", | |
| "font-family: monospace;\n", | |
| "white-space: pre;\n", | |
| "display: block;\n", | |
| "}\n", | |
| "#unshowable {\n", | |
| "color: red;\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".err-msg.in.collapse {\n", | |
| "padding-top: 0.7em;\n", | |
| "}\n", | |
| ".highlight-code {\n", | |
| "white-space: pre;\n", | |
| "font-family: monospace;\n", | |
| "}\n", | |
| ".suggestion-warning { \n", | |
| "font-weight: bold;\n", | |
| "color: rgb(200, 130, 0);\n", | |
| "}\n", | |
| ".suggestion-error { \n", | |
| "font-weight: bold;\n", | |
| "color: red;\n", | |
| "}\n", | |
| ".suggestion-name {\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| "</style><div class=\"suggestion-name\" style=\"clear:both;\">Evaluate</div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Found:</div><div class=\"highlight-code\" id=\"haskell\">null []</div></div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Why Not:</div><div class=\"highlight-code\" id=\"haskell\">True</div></div>" | |
| ], | |
| "text/plain": [ | |
| "Line 1: Evaluate\n", | |
| "Found:\n", | |
| "null []\n", | |
| "Why not:\n", | |
| "True" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "False" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "True" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "null [1,2,3]\n", | |
| "null []" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `null` リストが空リストの場合 `True`を返し、そうで無い場合 `False` を返" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 15, | |
| "metadata": { | |
| "scrolled": true | |
| }, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[1,2,3,4,5]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "reverse [5,4,3,2,1]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `reverse` リストの要素を逆順にして返す" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 16, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/html": [ | |
| "<style>/* Styles used for the Hoogle display in the pager */\n", | |
| ".hoogle-doc {\n", | |
| "display: block;\n", | |
| "padding-bottom: 1.3em;\n", | |
| "padding-left: 0.4em;\n", | |
| "}\n", | |
| ".hoogle-code {\n", | |
| "display: block;\n", | |
| "font-family: monospace;\n", | |
| "white-space: pre;\n", | |
| "}\n", | |
| ".hoogle-text {\n", | |
| "display: block;\n", | |
| "}\n", | |
| ".hoogle-name {\n", | |
| "color: green;\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".hoogle-head {\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".hoogle-sub {\n", | |
| "display: block;\n", | |
| "margin-left: 0.4em;\n", | |
| "}\n", | |
| ".hoogle-package {\n", | |
| "font-weight: bold;\n", | |
| "font-style: italic;\n", | |
| "}\n", | |
| ".hoogle-module {\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".hoogle-class {\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".get-type {\n", | |
| "color: green;\n", | |
| "font-weight: bold;\n", | |
| "font-family: monospace;\n", | |
| "display: block;\n", | |
| "white-space: pre-wrap;\n", | |
| "}\n", | |
| ".show-type {\n", | |
| "color: green;\n", | |
| "font-weight: bold;\n", | |
| "font-family: monospace;\n", | |
| "margin-left: 1em;\n", | |
| "}\n", | |
| ".mono {\n", | |
| "font-family: monospace;\n", | |
| "display: block;\n", | |
| "}\n", | |
| ".err-msg {\n", | |
| "color: red;\n", | |
| "font-style: italic;\n", | |
| "font-family: monospace;\n", | |
| "white-space: pre;\n", | |
| "display: block;\n", | |
| "}\n", | |
| "#unshowable {\n", | |
| "color: red;\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".err-msg.in.collapse {\n", | |
| "padding-top: 0.7em;\n", | |
| "}\n", | |
| ".highlight-code {\n", | |
| "white-space: pre;\n", | |
| "font-family: monospace;\n", | |
| "}\n", | |
| ".suggestion-warning { \n", | |
| "font-weight: bold;\n", | |
| "color: rgb(200, 130, 0);\n", | |
| "}\n", | |
| ".suggestion-error { \n", | |
| "font-weight: bold;\n", | |
| "color: red;\n", | |
| "}\n", | |
| ".suggestion-name {\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| "</style><div class=\"suggestion-name\" style=\"clear:both;\">Take on a non-positive</div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Found:</div><div class=\"highlight-code\" id=\"haskell\">take 0 [6, 6, 6]</div></div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Why Not:</div><div class=\"highlight-code\" id=\"haskell\">[]</div></div>" | |
| ], | |
| "text/plain": [ | |
| "Line 1: Take on a non-positive\n", | |
| "Found:\n", | |
| "take 0 [6, 6, 6]\n", | |
| "Why not:\n", | |
| "[]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[5,4,3]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[3]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[1,2]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "take 3 [5,4,3,2,1]\n", | |
| "take 1 [3,9,3]\n", | |
| "take 5 [1,2]\n", | |
| "take 0 [6,6,6]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `take` 先頭から指定した数の要素数のリストを返す。0のときは空リストを返す" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 17, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[1,5,6]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[1,2,3,4]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "drop 3 [8,4,2,1,5,6]\n", | |
| "drop 0 [1,2,3,4]\n", | |
| "drop 100 [1,2,3,4]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `drop` 先頭から指定した数の要素数を取り除いたリストを返す。指定した数がリストの長さ以上の場合は空リストを返す" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 18, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "1" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "minimum [8,4,2,1,5,6]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `minimum` リストの最小値を返す" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 19, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "9" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "maximum [1,9,2,3,4]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `maximum` リストの最大値を返す" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 20, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "31" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "sum [5,2,1,6,3,2,5,7] " | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `sum` リストの要素の和を返す" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 21, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "24" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "0" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "product [6,2,1,2]\n", | |
| "product [1,2,5,6,7,9,2,0]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| " `product` リストの要素の積を返す" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 22, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "True" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "False" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "4 `elem` [3,4,5,6]\n", | |
| "10 `elem` [3,4,5,6]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `elem` リストに指定した値が入っている場合 `True`を返し、そうで無い場合 `False` を返す\n", | |
| " - よく *infix* functionとして呼ばれる" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "## Texas ranges" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 23, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "\"abcdefghijklmnopqrstuvwxyz\"" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "\"ABCDEFGHIJKLMNOPQRSTUVWXYZ\"" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "\"ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\\\]^_`abcdefghijklmnopqrstuvwxyz\"" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "[1..20]\n", | |
| "['a'..'z']\n", | |
| "['A'..'Z']\n", | |
| "['A'..'z']" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- rangeは等差数列で要素が列挙可能なlistを作成する一つの方法" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 24, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[2,4,6,8,10,12,14,16,18,20]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[3,6,9,12,15,18]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "[2,4..20]\n", | |
| "[3,6..20]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- rangeはstepを指定することもできる\n", | |
| "- 2のべき乗みたいな等比数列はうまく生成できない" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 25, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[0.1,0.3,0.5,0.7,0.8999999999999999,1.0999999999999999]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "[0.1, 0.3..1]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- 浮動小数点のrangeは丸め誤差がでるので使わない方がよい" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "## 無限リスト\n", | |
| "- 上限を指定しないことで無限listを作成することができる\n", | |
| "- Haskellは遅延評価と無限listを利用してlist生成のスマートな書き方ができる\n", | |
| " - not smart `[13,26..24*13]`\n", | |
| " - smart `take 24 [13,26..]`\n", | |
| " - Haskellは即時に無限リストを評価することはない\n", | |
| "\n", | |
| "### 無限listを生成する関" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 26, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[1,2,3,1,2,3,1,2,3,1]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "\"LOL LOL LOL \"" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "take 10 (cycle [1,2,3])\n", | |
| "take 12 (cycle \"LOL \")" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `cycle` 指定したリストの要素を繰り返す無限listを返す" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 27, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/html": [ | |
| "<style>/* Styles used for the Hoogle display in the pager */\n", | |
| ".hoogle-doc {\n", | |
| "display: block;\n", | |
| "padding-bottom: 1.3em;\n", | |
| "padding-left: 0.4em;\n", | |
| "}\n", | |
| ".hoogle-code {\n", | |
| "display: block;\n", | |
| "font-family: monospace;\n", | |
| "white-space: pre;\n", | |
| "}\n", | |
| ".hoogle-text {\n", | |
| "display: block;\n", | |
| "}\n", | |
| ".hoogle-name {\n", | |
| "color: green;\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".hoogle-head {\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".hoogle-sub {\n", | |
| "display: block;\n", | |
| "margin-left: 0.4em;\n", | |
| "}\n", | |
| ".hoogle-package {\n", | |
| "font-weight: bold;\n", | |
| "font-style: italic;\n", | |
| "}\n", | |
| ".hoogle-module {\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".hoogle-class {\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".get-type {\n", | |
| "color: green;\n", | |
| "font-weight: bold;\n", | |
| "font-family: monospace;\n", | |
| "display: block;\n", | |
| "white-space: pre-wrap;\n", | |
| "}\n", | |
| ".show-type {\n", | |
| "color: green;\n", | |
| "font-weight: bold;\n", | |
| "font-family: monospace;\n", | |
| "margin-left: 1em;\n", | |
| "}\n", | |
| ".mono {\n", | |
| "font-family: monospace;\n", | |
| "display: block;\n", | |
| "}\n", | |
| ".err-msg {\n", | |
| "color: red;\n", | |
| "font-style: italic;\n", | |
| "font-family: monospace;\n", | |
| "white-space: pre;\n", | |
| "display: block;\n", | |
| "}\n", | |
| "#unshowable {\n", | |
| "color: red;\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| ".err-msg.in.collapse {\n", | |
| "padding-top: 0.7em;\n", | |
| "}\n", | |
| ".highlight-code {\n", | |
| "white-space: pre;\n", | |
| "font-family: monospace;\n", | |
| "}\n", | |
| ".suggestion-warning { \n", | |
| "font-weight: bold;\n", | |
| "color: rgb(200, 130, 0);\n", | |
| "}\n", | |
| ".suggestion-error { \n", | |
| "font-weight: bold;\n", | |
| "color: red;\n", | |
| "}\n", | |
| ".suggestion-name {\n", | |
| "font-weight: bold;\n", | |
| "}\n", | |
| "</style><div class=\"suggestion-name\" style=\"clear:both;\">Use replicate</div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Found:</div><div class=\"highlight-code\" id=\"haskell\">take 10 (repeat 5)</div></div><div class=\"suggestion-row\" style=\"float: left;\"><div class=\"suggestion-warning\">Why Not:</div><div class=\"highlight-code\" id=\"haskell\">replicate 10 5</div></div>" | |
| ], | |
| "text/plain": [ | |
| "Line 1: Use replicate\n", | |
| "Found:\n", | |
| "take 10 (repeat 5)\n", | |
| "Why not:\n", | |
| "replicate 10 5" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[5,5,5,5,5,5,5,5,5,5]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "take 10 (repeat 5)" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `repeat` 指定した値を繰り返す無限listを返す" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 28, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[5,5,5,5,5,5,5,5,5,5]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "replicate 10 5" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- `take`と `repeat`を使う場合、 `replicate`関数を用いて簡単に書ける" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "## I'm a list comprehension" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 29, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[2,4,6,8,10,12,14,16,18,20]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "[x*2 | x <- [1..10]]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- listだけでは表現しにくい複雑な集合を取りたい場合にリスト内包表記を記述する" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 30, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[12,14,16,18,20]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "[x*2 | x <- [1..10], x >= 6]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 31, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[52,59,66,73,80,87,94]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "[ x | x <- [50..100], x `mod` 7 == 3]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- 述語によって`filtering`できる" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 32, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[\"BOOM!\",\"BOOM!\",\"BANG!\",\"BANG!\"]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "boomBangs xs = [ if x < 10 then \"BOOM!\" else \"BANG!\" | x <- xs, odd x]\n", | |
| "boomBangs [7..13]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 33, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[10,11,12,14,16,17,18,20]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "[ x | x <- [10..20], x /= 13, x /= 15, x /= 19]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- 述語はカンマ区切りで複数指定できる" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 34, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[16,20,22,40,50,55,80,100,110]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "[ x*y | x <- [2,5,10], y <- [8,10,11]]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 35, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[55,80,100,110]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "[ x*y | x <- [2,5,10], y <- [8,10,11], x*y > 50]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 36, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[\"lazy hobo\",\"lazy frog\",\"lazy pope\",\"grouchy hobo\",\"grouchy frog\",\"grouchy pope\",\"scheming hobo\",\"scheming frog\",\"scheming pope\"]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "let nouns = [\"hobo\",\"frog\",\"pope\"]\n", | |
| "let adjectives = [\"lazy\",\"grouchy\",\"scheming\"]\n", | |
| "[adjective ++ \" \" ++ noun | adjective <- adjectives, noun <- nouns]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- ソースとなるリストも複数指定可能" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 37, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "4" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "5" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "length' xs = sum [1 | _ <- xs]\n", | |
| "length' [5,4,2,1]\n", | |
| "length' \"hello\"" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- リストからとってきた変数を利用しないときは `_`と書く" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 38, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "\"HA\"" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| }, | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "\"ILIKEFROGS\"" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "removeNonUppercase st = [ c | c <- st, c `elem` ['A'..'Z']]\n", | |
| "removeNonUppercase \"Hahaha! Ahahaha!\"\n", | |
| "removeNonUppercase \"IdontLIKEFROGS\"" | |
| ] | |
| }, | |
| { | |
| "cell_type": "code", | |
| "execution_count": 39, | |
| "metadata": {}, | |
| "outputs": [ | |
| { | |
| "data": { | |
| "text/plain": [ | |
| "[[2,2,4],[2,4,6,8],[2,4,2,6,2,6]]" | |
| ] | |
| }, | |
| "metadata": {}, | |
| "output_type": "display_data" | |
| } | |
| ], | |
| "source": [ | |
| "let xxs = [[1,3,5,2,3,1,2,4,5],[1,2,3,4,5,6,7,8,9],[1,2,4,2,1,6,3,1,3,2,3,6]]\n", | |
| "[ [ x | x <- xs, even x ] | xs <- xxs]" | |
| ] | |
| }, | |
| { | |
| "cell_type": "markdown", | |
| "metadata": {}, | |
| "source": [ | |
| "- [集合 - Wikipedia](https://ja.wikipedia.org/wiki/%E9%9B%86%E5%90%88#%E8%A8%98%E6%B3%95)\n", | |
| "\n", | |
| "- [補足]Pythonにもリスト内包表記がある(Haskellを参考にした）" | |
| ] | |
| } | |
| ], | |
| "metadata": { | |
| "kernelspec": { | |
| "display_name": "Haskell", | |
| "language": "haskell", | |
| "name": "haskell" | |
| }, | |
| "language_info": { | |
| "codemirror_mode": "ihaskell", | |
| "file_extension": ".hs", | |
| "name": "haskell", | |
| "pygments_lexer": "Haskell", | |
| "version": "8.6.3" | |
| } | |
| }, | |
| "nbformat": 4, | |
| "nbformat_minor": 2 | |
| } |
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