Exception_Handling_&_Modules_and_Packages.ipynb

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      "name": "python3",
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      "name": "python"
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        "<a href=\"https://colab.research.google.com/github/AzadMehedi/Python/blob/main/Exception_Handling_%26_Modules_and_Packages.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>"
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      "metadata": {
        "id": "8tRXhnZrsxBs"
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    {
      "cell_type": "markdown",
      "source": [
        "### There are 2 stages where error may happen in a program\n",
        "\n",
        "- During compilation -> Syntax Error\n",
        "- During execution -> Exceptions"
      ],
      "metadata": {
        "id": "4UlrdHBss4dI"
      }
    },
    {
      "cell_type": "markdown",
      "source": [
        "### Syntax Error\n",
        "\n",
        "- Something in the program is not written according to the program grammar.\n",
        "- Error is raised by the interpreter/compiler\n",
        "- You can solve it by rectifying the program\n"
      ],
      "metadata": {
        "id": "GmGBDze2s8i0"
      }
    },
    {
      "cell_type": "code",
      "source": [
        "# examples of syntax error\n",
        "print 'Hello world'"
      ],
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        },
        "id": "6O2qR_7Ds5jt",
        "outputId": "09e8c1bd-8ce4-49c6-d991-83b6064772b3"
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      "execution_count": null,
      "outputs": [
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          "output_type": "error",
          "ename": "SyntaxError",
          "evalue": "ignored",
          "traceback": [
            "\u001b[0;36m  File \u001b[0;32m\"<ipython-input-1-0db6289d6639>\"\u001b[0;36m, line \u001b[0;32m2\u001b[0m\n\u001b[0;31m    print 'Hello world'\u001b[0m\n\u001b[0m          ^\u001b[0m\n\u001b[0;31mSyntaxError\u001b[0m\u001b[0;31m:\u001b[0m Missing parentheses in call to 'print'. Did you mean print('Hello world')?\n"
          ]
        }
      ]
    },
    {
      "cell_type": "markdown",
      "source": [
        "### Other examples of syntax error\n",
        "\n",
        "- Leaving symbols like colon,brackets\n",
        "- Misspelling a keyword\n",
        "- Incorrect indentation\n",
        "- empty if/else/loops/class/functions"
      ],
      "metadata": {
        "id": "S5f-myYrtBDA"
      }
    },
    {
      "cell_type": "code",
      "source": [
        "a =5\n",
        "iff a==3:\n",
        "  print('hello')"
      ],
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          "height": 132
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        "id": "22jQJZQrtCI-",
        "outputId": "bb47be54-3cf2-4ef4-d523-4b9439cbce7c"
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      "execution_count": null,
      "outputs": [
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          "output_type": "error",
          "ename": "SyntaxError",
          "evalue": "ignored",
          "traceback": [
            "\u001b[0;36m  File \u001b[0;32m\"<ipython-input-2-2b85c1bd3961>\"\u001b[0;36m, line \u001b[0;32m2\u001b[0m\n\u001b[0;31m    iff a==3:\u001b[0m\n\u001b[0m        ^\u001b[0m\n\u001b[0;31mSyntaxError\u001b[0m\u001b[0;31m:\u001b[0m invalid syntax\n"
          ]
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "a =5\n",
        "if a==3:\n",
        "print('hello')"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 132
        },
        "id": "ZJFX7qrfuzsy",
        "outputId": "9a27d863-efa8-45cb-8023-80c7f92e2024"
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      "execution_count": null,
      "outputs": [
        {
          "output_type": "error",
          "ename": "IndentationError",
          "evalue": "ignored",
          "traceback": [
            "\u001b[0;36m  File \u001b[0;32m\"<ipython-input-3-6d4f6e232395>\"\u001b[0;36m, line \u001b[0;32m3\u001b[0m\n\u001b[0;31m    print('hello')\u001b[0m\n\u001b[0m    ^\u001b[0m\n\u001b[0;31mIndentationError\u001b[0m\u001b[0;31m:\u001b[0m expected an indented block\n"
          ]
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "# IndexError\n",
        "# The IndexError is thrown when trying to access an item at an invalid index.\n",
        "L = [1,2,3,4]\n",
        "L[100]"
      ],
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        {
          "output_type": "error",
          "ename": "IndexError",
          "evalue": "ignored",
          "traceback": [
            "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
            "\u001b[0;31mIndexError\u001b[0m                                Traceback (most recent call last)",
            "\u001b[0;32m<ipython-input-5-8aae653875c4>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[1;32m      2\u001b[0m \u001b[0;31m# The IndexError is thrown when trying to access an item at an invalid index.\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m      3\u001b[0m \u001b[0mL\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0;34m[\u001b[0m\u001b[0;36m1\u001b[0m\u001b[0;34m,\u001b[0m\u001b[0;36m2\u001b[0m\u001b[0;34m,\u001b[0m\u001b[0;36m3\u001b[0m\u001b[0;34m,\u001b[0m\u001b[0;36m4\u001b[0m\u001b[0;34m]\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 4\u001b[0;31m \u001b[0mL\u001b[0m\u001b[0;34m[\u001b[0m\u001b[0;36m100\u001b[0m\u001b[0;34m]\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
            "\u001b[0;31mIndexError\u001b[0m: list index out of range"
          ]
        }
      ]
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    {
      "cell_type": "code",
      "source": [
        "# ModuleNotFoundError\n",
        "# The ModuleNotFoundError is thrown when a module could not be found.\n",
        "import mathe\n",
        "math.floor(5.3)"
      ],
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          "height": 358
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        "id": "XHrH3K2hvJje",
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        {
          "output_type": "error",
          "ename": "ModuleNotFoundError",
          "evalue": "ignored",
          "traceback": [
            "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
            "\u001b[0;31mModuleNotFoundError\u001b[0m                       Traceback (most recent call last)",
            "\u001b[0;32m<ipython-input-7-c22b280c5807>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[1;32m      1\u001b[0m \u001b[0;31m# ModuleNotFoundError\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[0;31m# The ModuleNotFoundError is thrown when a module could not be found.\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 3\u001b[0;31m \u001b[0;32mimport\u001b[0m \u001b[0mmathe\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m      4\u001b[0m \u001b[0mmath\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mfloor\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;36m5.3\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
            "\u001b[0;31mModuleNotFoundError\u001b[0m: No module named 'mathe'",
            "",
            "\u001b[0;31m---------------------------------------------------------------------------\u001b[0;32m\nNOTE: If your import is failing due to a missing package, you can\nmanually install dependencies using either !pip or !apt.\n\nTo view examples of installing some common dependencies, click the\n\"Open Examples\" button below.\n\u001b[0;31m---------------------------------------------------------------------------\u001b[0m\n"
          ],
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            "actions": [
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                "action": "open_url",
                "actionText": "Open Examples",
                "url": "/notebooks/snippets/importing_libraries.ipynb"
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    {
      "cell_type": "code",
      "source": [
        "# KeyError\n",
        "# The KeyError is thrown when a key is not found\n",
        "d = {\n",
        "    'name': 'Mehedi'\n",
        "}\n",
        "d['age']"
      ],
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          "height": 201
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        "id": "ZHXS9SRPvSWh",
        "outputId": "fa3c5a3a-8fb4-4653-bfee-d27a8b5a032d"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "error",
          "ename": "KeyError",
          "evalue": "ignored",
          "traceback": [
            "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
            "\u001b[0;31mKeyError\u001b[0m                                  Traceback (most recent call last)",
            "\u001b[0;32m<ipython-input-9-2b36b23d9d80>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[1;32m      4\u001b[0m     \u001b[0;34m'name'\u001b[0m\u001b[0;34m:\u001b[0m \u001b[0;34m'Mehedi'\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m      5\u001b[0m }\n\u001b[0;32m----> 6\u001b[0;31m \u001b[0md\u001b[0m\u001b[0;34m[\u001b[0m\u001b[0;34m'age'\u001b[0m\u001b[0;34m]\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
            "\u001b[0;31mKeyError\u001b[0m: 'age'"
          ]
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "# TypeError\n",
        "# The TypeError is thrown when an operation or function is applied to an object of an inappropriate type.\n",
        "1+'a'"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 201
        },
        "id": "arMmyvNPveRk",
        "outputId": "a86b5c67-f59c-4171-bc64-9132bbce1eae"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "error",
          "ename": "TypeError",
          "evalue": "ignored",
          "traceback": [
            "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
            "\u001b[0;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
            "\u001b[0;32m<ipython-input-13-b61f5a703a83>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[1;32m      1\u001b[0m \u001b[0;31m# TypeError\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[0;31m# The TypeError is thrown when an operation or function is applied to an object of an inappropriate type.\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 3\u001b[0;31m \u001b[0;36m1\u001b[0m\u001b[0;34m+\u001b[0m\u001b[0;34m'a'\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
            "\u001b[0;31mTypeError\u001b[0m: unsupported operand type(s) for +: 'int' and 'str'"
          ]
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "# ValueError\n",
        "# The ValueError is thrown when a function's argument is of an inappropriate type.\n",
        "int('a')"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 201
        },
        "id": "zsySgtB5vx2A",
        "outputId": "0aec57d9-d417-452b-e20d-2814b7a3c1b8"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "error",
          "ename": "ValueError",
          "evalue": "ignored",
          "traceback": [
            "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
            "\u001b[0;31mValueError\u001b[0m                                Traceback (most recent call last)",
            "\u001b[0;32m<ipython-input-11-e419d2a084b4>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[1;32m      1\u001b[0m \u001b[0;31m# ValueError\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[0;31m# The ValueError is thrown when a function's argument is of an inappropriate type.\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 3\u001b[0;31m \u001b[0mint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m'a'\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
            "\u001b[0;31mValueError\u001b[0m: invalid literal for int() with base 10: 'a'"
          ]
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "# NameError\n",
        "# The NameError is thrown when an object could not be found.\n",
        "print(i)"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 201
        },
        "id": "ZZ9jR5kbwD_i",
        "outputId": "7aca73dc-500a-487e-aa2b-bf27ba9beff1"
      },
      "execution_count": null,
      "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-14-9170b67c95b3>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[1;32m      1\u001b[0m \u001b[0;31m# NameError\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[0;31m# The NameError is thrown when an object could not be found.\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 3\u001b[0;31m \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mi\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 'i' is not defined"
          ]
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "# AttributeError\n",
        "L= [1,2,3]\n",
        "L.upper()"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 201
        },
        "id": "PXQO89qqwe7l",
        "outputId": "04e7f935-070b-4420-86d8-90731f8b0666"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "error",
          "ename": "AttributeError",
          "evalue": "ignored",
          "traceback": [
            "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
            "\u001b[0;31mAttributeError\u001b[0m                            Traceback (most recent call last)",
            "\u001b[0;32m<ipython-input-15-2385703bfd0c>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[1;32m      1\u001b[0m \u001b[0;31m# AttributeError\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[0mL\u001b[0m\u001b[0;34m=\u001b[0m \u001b[0;34m[\u001b[0m\u001b[0;36m1\u001b[0m\u001b[0;34m,\u001b[0m\u001b[0;36m2\u001b[0m\u001b[0;34m,\u001b[0m\u001b[0;36m3\u001b[0m\u001b[0;34m]\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 3\u001b[0;31m \u001b[0mL\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mupper\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[0m",
            "\u001b[0;31mAttributeError\u001b[0m: 'list' object has no attribute 'upper'"
          ]
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [],
      "metadata": {
        "id": "zEr6nq7YwqBX"
      },
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "source": [
        "### Exceptions\n",
        "\n",
        "If things go wrong during the execution of the program(runtime). It generally happens when something unforeseen has happened.\n",
        "\n",
        "- Exceptions are raised by python runtime\n",
        "- You have to takle is on the fly\n",
        "\n",
        "#### **Examples**\n",
        "\n",
        "- Memory overflow\n",
        "- Divide by 0 -> logical error\n",
        "- Database error"
      ],
      "metadata": {
        "id": "u8LYDskrwtcV"
      }
    },
    {
      "cell_type": "code",
      "source": [
        "# Why is it important to handle exceptions\n",
        "# how to handle exceptions\n",
        "# -> Try except block\n"
      ],
      "metadata": {
        "id": "YeAjcpvVwtsS"
      },
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "code",
      "source": [
        "# let's create a file\n",
        "with open('sample.txt','w') as f:\n",
        "  f.write('Hello world ')"
      ],
      "metadata": {
        "id": "HUR0NznezWiB"
      },
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "code",
      "source": [
        "# try except demo\n",
        "try:\n",
        "  with open('sample1.txt','r') as f:\n",
        "    print(f.read())\n",
        "except:\n",
        "  print('Sorry fiel not found.')"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/"
        },
        "id": "G3jl5bJ9zvul",
        "outputId": "db6d5c6b-f8bc-4d3f-d3d1-6186ab1e1825"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "stream",
          "name": "stdout",
          "text": [
            "Sorry fiel not found.\n"
          ]
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "# catching specific exception\n",
        "try:\n",
        "  m=5\n",
        "  f = open('sample.txt','r')\n",
        "  print(f.read())\n",
        "  print(m)\n",
        "  print(5/2)\n",
        "  l=[1,2,3]\n",
        "  l[100]\n",
        "\n",
        "except FileNotFoundError:\n",
        "  print('File not found')\n",
        "\n",
        "except NameError:\n",
        "  print('Variable not defined.')\n",
        "\n",
        "except ZeroDivisionError:\n",
        "  print('cant divide by 0')\n",
        "\n",
        "except Exception as e:\n",
        "  print(e)\n"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/"
        },
        "id": "DBucM7w_0Up9",
        "outputId": "52745dab-6bb4-4b97-a7b8-4765d6cc5389"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "stream",
          "name": "stdout",
          "text": [
            "Hello world \n",
            "5\n",
            "2.5\n",
            "list index out of range\n"
          ]
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "# else   -> when you are sure about try will 100% execute.\n",
        "# except  -> when we know there is problem in try.\n",
        "\n",
        "try:\n",
        "  f = open('sample1.txt','r')\n",
        "except FileNotFoundError:\n",
        "  print('file is not found')\n",
        "except Exception:\n",
        "  print('There is somethig wrong')\n",
        "else:\n",
        "  print(f.read)"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/"
        },
        "id": "2-MbKuSC3OJK",
        "outputId": "25c5b490-aa73-489e-82c5-6c9310daa386"
      },
      "execution_count": null,
      "outputs": [
        {
          "output_type": "stream",
          "name": "stdout",
          "text": [
            "file is not found\n"
          ]
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "# finally    -> finally will execute anyhow.\n",
        "try:\n",
        "  f = open('sample1.txt','r')\n",
        "except FileNotFoundError:\n",
        "  print('file is not found')\n",
        "except Exception:\n",
        "  print('There is somethig wrong')\n",
        "else:\n",
        "  print(f.read)\n",
        "finally:\n",
        "  print('Must have print')"
      ],
      "metadata": {
        "id": "p-6SNNmUbs6l",
        "colab": {
          "base_uri": "https://localhost:8080/"
        },
        "outputId": "0007fec8-5e40-47cc-b8c2-9041852b9bb0"
      },
      "execution_count": 1,
      "outputs": [
        {
          "output_type": "stream",
          "name": "stdout",
          "text": [
            "file is not found\n",
            "Must have print\n"
          ]
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [],
      "metadata": {
        "id": "Y4tf24eniFGr"
      },
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "markdown",
      "source": [
        "# raise Exception\n",
        "- In Python programming, exceptions are raised when errors occur at runtime. \n",
        "- We can also manually raise exceptions using the raise keyword.\n",
        "- We can optionally pass values to the exception to clarify why that exception was raised"
      ],
      "metadata": {
        "id": "UktjRh51iHXO"
      }
    },
    {
      "cell_type": "code",
      "source": [
        "raise NameError ('trying to raise an error')"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 167
        },
        "id": "DySJxOrEiIR2",
        "outputId": "fb06842b-5bfd-45b3-e1be-d44f6038089a"
      },
      "execution_count": 4,
      "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-4-423169427d41>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0;32mraise\u001b[0m \u001b[0mNameError\u001b[0m \u001b[0;34m(\u001b[0m\u001b[0;34m'trying to raise an error'\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: trying to raise an error"
          ]
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "raise ZeroDivisionError('aise hi try kar raha hu')\n",
        "# Java\n",
        "# try -> try\n",
        "# except -> catch\n",
        "# raise -> throw"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/",
          "height": 236
        },
        "id": "dAZANj44iRmM",
        "outputId": "16d5bebf-ddec-4e4c-e077-95b6ea80a517"
      },
      "execution_count": 5,
      "outputs": [
        {
          "output_type": "error",
          "ename": "ZeroDivisionError",
          "evalue": "ignored",
          "traceback": [
            "\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
            "\u001b[0;31mZeroDivisionError\u001b[0m                         Traceback (most recent call last)",
            "\u001b[0;32m<ipython-input-5-449a2aa7046e>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0;32mraise\u001b[0m \u001b[0mZeroDivisionError\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m'aise hi try kar raha hu'\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      2\u001b[0m \u001b[0;31m# Java\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m      3\u001b[0m \u001b[0;31m# try -> try\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[0;31m# except -> catch\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m      5\u001b[0m \u001b[0;31m# raise -> throw\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
            "\u001b[0;31mZeroDivisionError\u001b[0m: aise hi try kar raha hu"
          ]
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "class MyException(Exception):\n",
        "  def __init__(self, message):\n",
        "    print(message)\n",
        "\n",
        "\n",
        "class Bank:\n",
        "  def __init__(self, balance):\n",
        "    self.balance = balance\n",
        "\n",
        "  def withdraw(self, amount):\n",
        "    if amount < 0:\n",
        "      raise MyException('Amount can not be -ve')\n",
        "    if self.balance < amount:\n",
        "      raise MyException('Not enougn money')\n",
        "    self.balance = self.balance - amount\n",
        "    self.amount = self.balance - amount\n",
        "\n",
        "obj = Bank(10000)\n",
        "try:\n",
        "  obj.withdraw(15000)\n",
        "except MyException as e:\n",
        "  pass\n",
        "else:\n",
        "  print(obj.balance)\n"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/"
        },
        "id": "GB3T0RTGjJ3Z",
        "outputId": "0048f7cd-c879-4bba-af47-b0373b01bcb1"
      },
      "execution_count": 10,
      "outputs": [
        {
          "output_type": "stream",
          "name": "stdout",
          "text": [
            "Not enougn money\n"
          ]
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [
        "# custom exception class\n",
        "\n",
        "class Bank:\n",
        "  def __init__(self, balance):\n",
        "    self.balance = balance\n",
        "\n",
        "  def withdraw(self, amount):\n",
        "    if amount < 0:\n",
        "      raise Exception('Amount can not be -ve')\n",
        "    if self.balance < amount:\n",
        "      raise Exception('Not enougn money')\n",
        "    self.balance = self.balance - amount\n",
        "    self.amount = self.balance - amount\n",
        "\n",
        "obj = Bank(10000)\n",
        "try:\n",
        "  obj.withdraw(15000)\n",
        "except Exception as e:\n",
        "  print(e)\n",
        "else:\n",
        "  print(obj.balance)\n"
      ],
      "metadata": {
        "id": "g5j7NvoTlZB6"
      },
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "code",
      "source": [
        "# from IPython.lib import security\n",
        "# why we create our own exception class\n",
        "\n",
        "class SecurityError(Exception):\n",
        "  def __init__(self, message):\n",
        "    print(message)\n",
        "\n",
        "  def logout(self):\n",
        "    print('logout')\n",
        "  \n",
        "\n",
        "class Google:\n",
        "  def __init__(self, name, email, password, device):\n",
        "    self.name = name\n",
        "    self.email = email\n",
        "    self.password = password\n",
        "    self.device = device\n",
        "\n",
        "  def login(self, email, password, device):\n",
        "    if device != self.device:\n",
        "      raise SecurityError('You are in danger.')\n",
        "    if email == self.email and password == self.password:\n",
        "      print('welcome')\n",
        "    else:\n",
        "      print('Login error')\n",
        "\n",
        "obj = Google('Evan','abc@gmail.com', '1234', 'android')\n",
        "\n",
        "try:\n",
        "  obj.login('abc@gmail.com', '1234', 'windows')\n",
        "except SecurityError as e:\n",
        "  e.logout()\n",
        "else:\n",
        "  print(obj.name)\n",
        "finally:\n",
        "  print('Database connection closed.')\n",
        "\n"
      ],
      "metadata": {
        "colab": {
          "base_uri": "https://localhost:8080/"
        },
        "id": "bHzb_Lsetv-r",
        "outputId": "96f3f40b-2658-4ce2-d5e8-99cb694ede82"
      },
      "execution_count": 17,
      "outputs": [
        {
          "output_type": "stream",
          "name": "stdout",
          "text": [
            "You are in danger.\n",
            "logout\n",
            "Database connection closed.\n"
          ]
        }
      ]
    },
    {
      "cell_type": "code",
      "source": [],
      "metadata": {
        "id": "IjKy6Ks17JUM"
      },
      "execution_count": null,
      "outputs": []
    }
  ]
}