003_Python_if_elif_else_statement .ipynb

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    "<small><small><i>\n",
    "All the IPython Notebooks in this lecture series by Dr. Milan Parmar are available @ **[GitHub](https://github.com/milaan9/03_Python_Flow_Control)**\n",
    "</i></small></small>"
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    "# Python `if-elif-else` statement\n",
    "\n",
    "So far, we have presented a Boolean option for conditional statements, with each **[if statement](https://github.com/milaan9/03_Python_Flow_Control/blob/main/001_Python_if_statement.ipynb)** evaluating to either **`True`** or **`False`**. In Python, the **`if-elif-else`** condition statement has an **`elif`** keyword used to chain multiple conditions one after another."
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    "### Syntax:\n",
    "\n",
    "```python\n",
    "if condition-1:  \n",
    "     statement 1 \n",
    "elif condition-2:\n",
    "     stetement 2 \n",
    "elif condition-3:\n",
    "     stetement 3 \n",
    "     ...         \n",
    "else:            \n",
    "     statement  \n",
    "```\n",
    "\n",
    "1. The **`elif`** is short for else if. It allows us to check for multiple expressions.\n",
    "\n",
    "2. If the condition for **`if`** is **`False`**, it checks the condition of the next **`elif`** block and so on.\n",
    "\n",
    "3. If all the conditions are **`False`**, the body of **`else`** is executed.\n",
    "\n",
    "4. Only one block among the several **`if-elif-else`** blocks is executed according to the condition.\n",
    "\n",
    "5. The **`if`** block can have only one **`else`** block. But it can have multiple **`elif`** blocks.\n",
    "\n",
    "<div>\n",
    "<img src=\"img/eif0.png\" width=\"500\"/>\n",
    "</div>"
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      "Zero\n"
     ]
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   "source": [
    "# Example 1:\n",
    "\n",
    "'''In this program, we check if the number is positive or negative or zero and \n",
    "display an appropriate message'''\n",
    "\n",
    "num = 0\n",
    "\n",
    "# Try these two variations as well:\n",
    "# num = 0\n",
    "# num = -4.5\n",
    "\n",
    "if num > 0:\n",
    "    print(\"Positive number\")\n",
    "elif num == 0:\n",
    "    print(\"Zero\")\n",
    "else:\n",
    "    print(\"Negative number\")"
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    "**Explanation:**\n",
    "\n",
    "When variable **`num`** is positive, **`Positive number`** is printed.\n",
    "\n",
    "If **`num`** is equal to 0, **`Zero`** is printed.\n",
    "\n",
    "If **`num`** is negative, **`Negative number`** is printed.    "
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     "text": [
      "num1 is equal to num2\n"
     ]
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   "source": [
    "# Example 2:\n",
    "\n",
    "num1, num2 = 5, 5\n",
    "if(num1 > num2):\n",
    "    print(\"num1 is greater than num2\")\n",
    "elif(num1 == num2):\n",
    "    print(\"num1 is equal to num2\")\n",
    "else:\n",
    "    print(\"num1 is less than num2\")"
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     "text": [
      "x<y\n"
     ]
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   "source": [
    "# Example 3:\n",
    "\n",
    "x = 10\n",
    "y = 12\n",
    "if x > y:\n",
    "    print(\"x>y\")\n",
    "elif x < y:\n",
    "    print(\"x<y\")\n",
    "else:\n",
    "    print(\"x=y\")"
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      "A grade\n"
     ]
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   "source": [
    "# Example 4:\n",
    "\n",
    "grade = 96\n",
    "\n",
    "if grade >= 90:\n",
    "    print(\"A grade\")\n",
    "elif grade >=80:\n",
    "    print(\"B grade\")\n",
    "elif grade >=70:\n",
    "    print(\"C grade\")\n",
    "elif grade >= 65:\n",
    "    print(\"D grade\")\n",
    "else:\n",
    "    print(\"Failing grade\")"
   ]
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     "text": [
      "Admin\n",
      "Editor\n",
      "Guest\n",
      "Wrong entry\n"
     ]
    }
   ],
   "source": [
    "# Example 5:\n",
    "\n",
    "def user_check(choice):\n",
    "    if choice == 1:\n",
    "        print(\"Admin\")\n",
    "    elif choice == 2:\n",
    "        print(\"Editor\")\n",
    "    elif choice == 3:\n",
    "        print(\"Guest\")\n",
    "    else:\n",
    "        print(\"Wrong entry\")\n",
    "\n",
    "user_check(1)  # Admin\n",
    "user_check(2)  # Editor\n",
    "user_check(3)  # Guest\n",
    "user_check(4)  # Wrong entry"
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