3_functions_stack_diagram.ipynb

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      "name": "Untitled10.ipynb",
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      "name": "python3",
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        "<a href=\"https://colab.research.google.com/github/ys7yoo/python_lab/blob/master/3_functions_stack_diagram.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>"
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    {
      "cell_type": "markdown",
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        "id": "FxJd9RIjy9XF",
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      "source": [
        "## Arguments and parameters"
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "jTL4eKh3y_5i",
        "colab_type": "code",
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      },
      "source": [
        "def print_twice(bruce):\n",
        "  print(bruce)\n",
        "  print(bruce)"
      ],
      "execution_count": 0,
      "outputs": []
    },
    {
      "cell_type": "code",
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        "outputId": "23e41bfa-56a2-4d72-d8e4-5de8facea10e"
      },
      "source": [
        "print_twice(\"spam\")"
      ],
      "execution_count": 19,
      "outputs": [
        {
          "output_type": "stream",
          "text": [
            "spam\n",
            "spam\n"
          ],
          "name": "stdout"
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "UWtY1-Yez8uW",
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        "outputId": "ab154140-91e7-40c2-b70b-c9b2ecfe9e71"
      },
      "source": [
        "print_twice(42)"
      ],
      "execution_count": 20,
      "outputs": [
        {
          "output_type": "stream",
          "text": [
            "42\n",
            "42\n"
          ],
          "name": "stdout"
        }
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "vaV7ktvLy9k9",
        "colab_type": "text"
      },
      "source": [
        "## Parameters and variables (in a function) are *local*"
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "7-JkbsUXzD7L",
        "colab_type": "code",
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      },
      "source": [
        "def cat_twice(part1, part2):\n",
        "  cat = part1 + part2 # when part1 and part2 are strings, then \"+\" means concatenate\n",
        "  print_twice(cat)"
      ],
      "execution_count": 0,
      "outputs": []
    },
    {
      "cell_type": "code",
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        "outputId": "9b3fbfc1-9f23-4f7a-ada5-94bceff1b479"
      },
      "source": [
        "line1 = \"Bing tiddle \"\n",
        "line2 = \"tiddle bang.\"\n",
        "cat_twice(line1, line2)"
      ],
      "execution_count": 22,
      "outputs": [
        {
          "output_type": "stream",
          "text": [
            "Bing tiddle tiddle bang.\n",
            "Bing tiddle tiddle bang.\n"
          ],
          "name": "stdout"
        }
      ]
    },
    {
      "cell_type": "code",
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        "id": "U8OKm6_o07jm",
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          "height": 167
        },
        "outputId": "790e206b-065d-41e1-c0d4-c0ca869c85be"
      },
      "source": [
        "print(cat)"
      ],
      "execution_count": 23,
      "outputs": [
        {
          "output_type": "error",
          "ename": "NameError",
          "evalue": "ignored",
          "traceback": [
            "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
            "\u001b[0;31mNameError\u001b[0m                                 Traceback (most recent call last)",
            "\u001b[0;32m<ipython-input-23-34599fba884e>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mcat\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
            "\u001b[0;31mNameError\u001b[0m: name 'cat' is not defined"
          ]
        }
      ]
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    {
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        "outputId": "cebff04c-53d2-4405-9ec8-4f960f298e7f"
      },
      "source": [
        "print(part1)"
      ],
      "execution_count": 24,
      "outputs": [
        {
          "output_type": "error",
          "ename": "NameError",
          "evalue": "ignored",
          "traceback": [
            "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
            "\u001b[0;31mNameError\u001b[0m                                 Traceback (most recent call last)",
            "\u001b[0;32m<ipython-input-24-5d1036bfc0b1>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mpart1\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
            "\u001b[0;31mNameError\u001b[0m: name 'part1' is not defined"
          ]
        }
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "oHPeYElH1q0G",
        "colab_type": "code",
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      },
      "source": [
        "def print_name(cat):\n",
        "  cat = cat + \".\"\n",
        "  print(cat + \".\")"
      ],
      "execution_count": 0,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "Jil1lKu7zEhr",
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      },
      "source": [
        "## Stack diagram and `Traceback`\n",
        "https://github.com/AllenDowney/ThinkPython2/blob/master/book/figs/stack.pdf"
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "8_3tMZopzLj8",
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      },
      "source": [
        "# modify the function to introduce an error!\n",
        "def print_twice(bruce):\n",
        "  print(cat)\n",
        "  print(bruce)\n",
        "  print(bruce)"
      ],
      "execution_count": 0,
      "outputs": []
    },
    {
      "cell_type": "code",
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        "id": "FG9_2ZCn3bar",
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          "height": 330
        },
        "outputId": "3c0b13e7-9172-41e7-92fa-87e885c036d8"
      },
      "source": [
        "line1 = \"Bing tiddle \"\n",
        "line2 = \"tiddle bang.\"\n",
        "cat_twice(line1, line2)"
      ],
      "execution_count": 27,
      "outputs": [
        {
          "output_type": "error",
          "ename": "NameError",
          "evalue": "ignored",
          "traceback": [
            "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
            "\u001b[0;31mNameError\u001b[0m                                 Traceback (most recent call last)",
            "\u001b[0;32m<ipython-input-27-9dbe65460850>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[1;32m      1\u001b[0m \u001b[0mline1\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0;34m\"Bing tiddle \"\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m      2\u001b[0m \u001b[0mline2\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0;34m\"tiddle bang.\"\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 3\u001b[0;31m \u001b[0mcat_twice\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mline1\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mline2\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
            "\u001b[0;32m<ipython-input-21-b8fbde3b645a>\u001b[0m in \u001b[0;36mcat_twice\u001b[0;34m(part1, part2)\u001b[0m\n\u001b[1;32m      1\u001b[0m \u001b[0;32mdef\u001b[0m \u001b[0mcat_twice\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mpart1\u001b[0m\u001b[0;34m,\u001b[0m \u001b[0mpart2\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m      2\u001b[0m   \u001b[0mcat\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mpart1\u001b[0m \u001b[0;34m+\u001b[0m \u001b[0mpart2\u001b[0m \u001b[0;31m# when part1 and part2 are strings, then \"+\" means concatenate\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 3\u001b[0;31m   \u001b[0mprint_twice\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mcat\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
            "\u001b[0;32m<ipython-input-26-7039fa0cd880>\u001b[0m in \u001b[0;36mprint_twice\u001b[0;34m(bruce)\u001b[0m\n\u001b[1;32m      1\u001b[0m \u001b[0;32mdef\u001b[0m \u001b[0mprint_twice\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mbruce\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 2\u001b[0;31m   \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mcat\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m      3\u001b[0m   \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mbruce\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m      4\u001b[0m   \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mbruce\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
            "\u001b[0;31mNameError\u001b[0m: name 'cat' is not defined"
          ]
        }
      ]
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        "id": "S4pfXDHA3hOl",
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      "source": [
        ""
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