{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Действия со списками\n",
    "Списки можно изменять, они умеют намного больше, чем другие последовательности.\n",
    "\n",
    "Создание списка:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[]\n",
      "[5, 6, 7]\n",
      "[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]\n",
      "['a', 'b', 'c']\n",
      "[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]\n"
     ]
    }
   ],
   "source": [
    "a = [10, 20, 30]   # перечисление\n",
    "# list() от любой последовательности\n",
    "print(list())  # пустой\n",
    "tup = 5, 6, 7  # кортеж\n",
    "print(list(tup))\n",
    "print(list(range(10)))\n",
    "print(list(\"abc\"))\n",
    "# еще есть генераторы списков, см. позже\n",
    "print([x ** 2 for x in range(10)])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "[Все действия со списками](https://docs.python.org/3/library/stdtypes.html#mutable-sequence-types)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "a\n",
      "a\n",
      "['x', 'b', 'c']\n"
     ]
    }
   ],
   "source": [
    "s = \"abc\"\n",
    "l = ['a', 'b', 'c']\n",
    "print(s[0])\n",
    "print(l[0])\n",
    "#s[0] = 'x'  # строки неизменяемые\n",
    "l[0] = 'x'  # так можно\n",
    "print(l)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['a', 'b']\n",
      "['A', 'B', 'C', 'c']\n"
     ]
    }
   ],
   "source": [
    "l = ['a', 'b', 'c']\n",
    "print(l[0:2])\n",
    "l[0:2] = ['A', 'B', 'C']\n",
    "print(l)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[10, 20, 30, 42]\n"
     ]
    }
   ],
   "source": [
    "l = [10, 20, 30]\n",
    "l.append(42)  # добавить в конец\n",
    "print(l)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Копирование:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[1000, 20, 30]\n",
      "[1000, 20, 30]\n",
      "[10, 20, 30]\n"
     ]
    }
   ],
   "source": [
    "l1 = [10, 20, 30]\n",
    "l2 = l1\n",
    "l3 = l1.copy()  # l1[:] эквиваленто, слайс создает новое\n",
    "l1[0] = 1000\n",
    "print(l1)\n",
    "print(l2)\n",
    "print(l3)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Дописывание в конец списка:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[10, 20, 30, 40, 50]\n",
      "[10, 20, 30]\n"
     ]
    }
   ],
   "source": [
    "l = [10, 20, 30]\n",
    "r = l\n",
    "l = l + [40, 50]\n",
    "print(l)\n",
    "print(r)  # l был присовоен новый список из l из [40, 50]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[10, 20, 30, 40, 50]\n",
      "[10, 20, 30, 40, 50]\n"
     ]
    }
   ],
   "source": [
    "l = [10, 20, 30]\n",
    "r = l\n",
    "l += [40, 50]  # или l.extend([40, 50])\n",
    "print(l)\n",
    "print(r)  # l изменен"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Сортировка, пока будем сортировать только в естественном поряке, т.е. числа по возрастанию, строки в алфавитном порядке"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[14, 52, 84, 3, 40, 22]\n",
      "[3, 14, 22, 40, 52, 84]\n",
      "[3, 14, 22, 40, 52, 84]\n",
      "['aaasdfasdf', 'aab', 'ooo', 'z']\n"
     ]
    }
   ],
   "source": [
    "l = [14, 52, 84, 3, 40, 22]\n",
    "# создает отсортированный список из любого перечисления\n",
    "r = sorted(l)\n",
    "print(l)  # sorted не изменяет l\n",
    "print(r)\n",
    "\n",
    "l.sort()  # сортировать сам l, т.е. l изменится\n",
    "print(l)\n",
    "\n",
    "# у строк алфавитный порядок, как в словаре\n",
    "print(sorted([\"aab\", \"aaasdfasdf\", \"ooo\", \"z\"]))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Функция `join` для соединения списка строк через указанный разделитель:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 50,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "10+20+30\n",
      "a b c\n"
     ]
    }
   ],
   "source": [
    "print(\"+\".join(['10', '20', '30']))\n",
    "print(\" \".join('abc'))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "## Генераторы списков (List comprehension)\n",
    "Это еще один способ создавать списки. Вы берете какую-то последовательность (список, кортеж, range, строка, ...), преобразуете каждый элемент по какому-то правилу и отфильтровываете часть элементов:\n",
    "\n",
    "`[_выражание_с_x_ for x in _последовательность_]`\n",
    "\n",
    "`[_выражание_с_x_ for x in _последовательность_ if _условие_на_x_]`\n",
    "\n",
    "Примеры:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[11, 21, 31]\n"
     ]
    }
   ],
   "source": [
    "L = [10, 20, 30]\n",
    "print([x + 1 for x in L])"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "переменная `x` перебрала все элементы последовательности, для каждого элемента вычислила `x + 1` и собрала все результаты в новый список."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[100, 400, 900]\n",
      "['10', '20', '30']\n",
      "[11, 21]\n"
     ]
    }
   ],
   "source": [
    "L = [10, 20, 30]\n",
    "print([x ** 2 for x in L])\n",
    "print([str(x) for x in L])  # будет список строк\n",
    "\n",
    "# теперь при переборе избавимся от всех x >= 25\n",
    "print([x + 1 for x in L if x < 25])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 30,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['a', 'b', 'c', 'd', 'e']\n",
      "['aa', 'bb', 'cc', 'dd', 'ee']\n"
     ]
    }
   ],
   "source": [
    "# строки тоже последовательности\n",
    "print([c for c in \"abcde\"])  # аналогично list(\"abcde\")\n",
    "print([c * 2 for c in \"abcde\"])  # аналогично list(\"abcde\")"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "Вложенные циклы в генераторе списков:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 37,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['ABC', 'XYZ', 'PQR']\n",
      "['a', 'b', 'c', 'x', 'y', 'z', 'p', 'q', 'r']\n",
      "['a from abc', 'b from abc', 'c from abc', 'x from xyz', 'y from xyz', 'z from xyz', 'p from pqr', 'q from pqr', 'r from pqr']\n",
      "['a from abc', 'b from abc', 'c from abc', 'x from xyz', 'z from xyz']\n"
     ]
    }
   ],
   "source": [
    "L = [\"abc\", \"xyz\", \"pqr\"]\n",
    "print([word.upper() for word in L])\n",
    "print([c for word in L for c in word])\n",
    "print([f'{c} from {word}' for word in L for c in word])\n",
    "print([f'{c} from {word}'\n",
    "       for word in L\n",
    "       if word[0] != 'p'\n",
    "       for c in word\n",
    "       if c != 'y'\n",
    "      ])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 49,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "[30, 90, 77]\n",
      "[11, 21, 41, 51, 34, 45]\n"
     ]
    }
   ],
   "source": [
    "L = [[10, 20], [40, 50], [33, 44]]\n",
    "print([sum(line) for line in L])\n",
    "print([num + 1 for line in L for num in line])"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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