{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "###
San Jose State University
Department of Applied Data Science

**DATA 200
Computational Programming for Data Analytics**

Spring 2023
Instructor: Ron Mak
" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# 4.3 Functions with Multiple Parameters" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "### Functions with Multiple Paraemters.\n", "#### A function can have any number of parameters, including no parameters. For example:" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "def maximum(value1, value2, value3):\n", " \"\"\"Return the maximum of three values.\"\"\"\n", " max_value = value1\n", " \n", " if value2 > max_value:\n", " max_value = value2\n", " if value3 > max_value:\n", " max_value = value3\n", " \n", " return max_value" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "maximum(12, 27, 36)" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "maximum(12.3, 45.6, 9.7)" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "maximum('yellow', 'red', 'orange')" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "maximum(13.5, -3, 7)" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Local Variables\n", "#### Inside our custom `maximum()` function, we introduced the variable `max_value`. This variable is **local** to the function. We cannot access it outside of the function:" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "max_value" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "#### If there were a variable also named `max_value` defined outside the function, it would be a totally different variable, as if it had a different name." ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Multiple Return Values\n", "\n", "#### A function can return more than one return value. We can optionally parenthesize the values, and they are implicitly packed into a **tuple**. After calling such a function, **unpack** the returned tuple by assigning the returned values to multiple variables at once (as many variables as there are values in the tuple)." ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "def square_and_cube(n):\n", " \"\"\"\n", " Return the square and the cube of the value of parameter n.\n", " \"\"\"\n", " return n*n, n*n*n" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "x = 3.14159\n", "square, cube = square_and_cube(x)\n", "\n", "print(f'The square and cube of {x} are {square:6.4f} and {cube:6.4f}')" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Python’s Built-In max and min Functions" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "max('yellow', 'red', 'orange', 'blue', 'green')" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "min(15, 9, 27, 14)" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "#### **EXERCISE:** Call function `max()` with the list `[14, 27, 5, 3]` as an argument. What is the result?" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "#### **EXERCISE:** Call function `min()` with the string `'orange'` as an argument. What is the result?" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Function Terminology from Computer Science\n", "#### In computer science literature, several terms refer to the parameters listed in parentheses in the function header, such as `value1`, `value2`, and `value3` of our custom `maximum()` function:\n", "- parameters\n", "- formal parameters\n", "- formal arguments\n", "\n", "#### When we call a function, the arguments we list in parentheses such as `15`, `9`, `27`, and `14` after the name of a function are refered to by several terms:\n", "- arguments\n", "- actual arguments\n", "- actual parameters\n", "\n", "#### Not to be overly pedantic and to avoid unnecessary confusion, let's simply use the term **parameters** in the function definition and **arguments** in the function call." ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "##########################################################################\n", "# (C) Copyright 2019 by Deitel & Associates, Inc. and #\n", "# Pearson Education, Inc. All Rights Reserved. #\n", "# #\n", "# DISCLAIMER: The authors and publisher of this book have used their #\n", "# best efforts in preparing the book. These efforts include the #\n", "# development, research, and testing of the theories and programs #\n", "# to determine their effectiveness. The authors and publisher make #\n", "# no warranty of any kind, expressed or implied, with regard to these #\n", "# programs or to the documentation contained in these books. The authors #\n", "# and publisher shall not be liable in any event for incidental or #\n", "# consequential damages in connection with, or arising out of, the #\n", "# furnishing, performance, or use of these programs. #\n", "##########################################################################\n" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [ "# Additional material (C) Copyright 2023 by Ronald Mak" ] } ], "metadata": { "kernelspec": { "display_name": "Python 3 (ipykernel)", "language": "python", "name": "python3" }, "language_info": { "codemirror_mode": { "name": "ipython", "version": 3 }, "file_extension": ".py", "mimetype": "text/x-python", "name": "python", "nbconvert_exporter": "python", "pygments_lexer": "ipython3", "version": "3.9.13" } }, "nbformat": 4, "nbformat_minor": 4 }