Chapter 6 - Functions.ipynb

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   "source": [
    "# Python - Functions"
   ]
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   "metadata": {},
   "source": [
    "A function is a block of organized, reusable code that is used to perform a single, related action. Functions provide better modularity for your application and a high degree of code reusing.\n",
    "\n",
    "As you already know, Python gives you many built-in functions like print(), etc. but you can also create your own functions. These functions are called user-defined functions."
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    "## Defining a Function\n",
    "\n",
    "You can define functions to provide the required functionality. Here are simple rules to define a function in Python.\n",
    "\n",
    "* Function blocks begin with the keyword def followed by the function name and parentheses ( ( ) ).\n",
    "\n",
    "* Any input parameters or arguments should be placed within these parentheses. You can also define parameters inside these parentheses.\n",
    "\n",
    "* The first statement of a function can be an optional statement - the documentation string of the function or docstring.\n",
    "\n",
    "* The code block within every function starts with a colon (:) and is indented.\n",
    "\n",
    "* The statement return [expression] exits a function, optionally passing back an expression to the caller. A return statement with no arguments is the same as return None."
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   "source": [
    "## Syntax"
   ]
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   "source": [
    "def function_name(parameters):\n",
    "   \"function_docstring\"\n",
    "   function_suite\n",
    "   return [expression]"
   ]
  },
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   "cell_type": "markdown",
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    "## Example\n",
    "\n",
    "The function below takes in a name as a string and print a hello statement"
   ]
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     "text": [
      "Hello Roberto!\n"
     ]
    }
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   "source": [
    "def hello_world(name):\n",
    "    print(f'Hello {name}!')\n",
    "\n",
    "hello_world('Roberto')"
   ]
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   "cell_type": "markdown",
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    "## Calling a Function\n",
    "\n",
    "Defining a function only gives it a name, specifies the parameters that are to be included in the function and structures the blocks of code.\n",
    "\n",
    "Once the basic structure of a function is finalized, you can execute it by calling it from another function or directly from the Python prompt. Following is the example to call printme() function −"
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    "## The return Statement\n",
    "\n",
    "The statement return [expression] exits a function, optionally passing back an expression to the caller. A return statement with no arguments is the same as return None.\n",
    "\n",
    "All the above examples are not returning any value. You can return a value from a function as follows −"
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   "source": [
    "# Exercises"
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    "### Define a function that accepts 2 values and prints its sum, subtraction and multiplication.\n",
    "\n",
    "Input:\n",
    "* Enter value of a = 7\n",
    "* Enter value of b = 5\n",
    "\n",
    "Expected output \n",
    "* Sum is = 12\n",
    "* Sub is = 2\n",
    "* Multiplication is = 35"
   ]
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  {
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   "execution_count": 8,
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   "source": [
    "# Type your code here"
   ]
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   "source": [
    "### Define a function that accepts lowercase words and returns uppercase words.\n",
    "\n",
    "* Input: roberto\n",
    "* Output: ROBERTO"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Type you code below"
   ]
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   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Write a Python function to sum all the numbers in a list.\n",
    "\n",
    "* sample list = [8, 2, 3, 0, 7]\n",
    "* Output: 20"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Type your code below"
   ]
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   "cell_type": "markdown",
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   "source": [
    "### Write a Python function to check whether a number falls in a given range. The function should take three parameters:\n",
    "\n",
    "* Number\n",
    "* Min or range\n",
    "* Max of range"
   ]
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  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [],
   "source": [
    "# Type your code below"
   ]
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   "cell_type": "markdown",
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   "source": [
    "### Write a program to fetch only even values from a dictionary. The function should take in a dictionary of values as input and output a list of the **keys** that have even values\n",
    "\n",
    "Output: ['val1', 'val2', 'val4', 'val6', 'val7', 'val9', 'val10']"
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    "values =  {'val1':10, \n",
    "           'val2':20, \n",
    "           'val3':23, \n",
    "           'val4':22,\n",
    "           'val5':25,\n",
    "           'val6':30,\n",
    "           'val7':48,\n",
    "           'val8':51,\n",
    "           'val9':54,\n",
    "           'val10':60}\n",
    "\n",
    "# Type your code here"
   ]
  }
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