1 Clarkson University Google IgniteCS

2 Have you ever wanted… To know how to make a computer do tasks for you?To learn the basics of how google works? Have a secret way to talk to your friends?

3 Our Topics Intro to Python Intro to Algorithms Intro to Networking

4 First what is computer science?

5 First what is computer science?The study of meeting people’s needs with computers

6 First without computers…Partner up, tell each other your: Name. Tell them one fun fact. Favorite flavor of ice cream and why. We are going to lead our partner through a maze. One of you will be our computer One of you will be our programmer

7 So what were the challenges?

8 So what were the challenges?Programmer could give confusing directions. Computer does not know what the programmers goal is.

9 What are some extra challenges we have with computers?

10 What are some extra challenges we have with computers?They don’t speak English.

11 The way we will program. Our computer: Raspberry PI 3Very affordable Easy to use Our language with the Computer: Python Very powerful language and easy to use We can find online help very easily

12 First a little business:Reasons to choose a computer So you can buy one for yourselves if you are interested in pursuing some of these projects further

13 Reminders before the fun.These are fragile computers. General things to follow: Please handle all boards along their edges Please only handle something when explicitly told to do so

14 Now fun Your kit should include: Two Raspberry Pi 3’s Two ScreensTwo Screen Power Supplies Four MicroUSB cables A USB Hub (optional) Two HDMI Cables Two Ethernet Cables Two USB Power Adapters Another box of fun (Leave that for later)

15 Let us set up our computersRemove the cables from the box. Split all items not in the components box evenly.

16 Let us set up our computersConnect the HDMI cable to the monitor and the other end to the Raspberry Pi.

17 Let us set up our computersConnect the mouse and keyboard to the USB ports on the Raspberry Pi.

18 Let us set up our computers. Open the components box, and take out the two MicroSD cards, and carefully place them in the MicroSD slots in the bottom of the Raspberry Pi. Be VERY delicate with them. The top of the SD card should face down to the table.

19 Let us set up our computersConnect the Screen Power Cable to the power strip at the center of your table. Please do not place the monitor on the board.

20 Let us set up our computersConnect the Raspberry Pi’s MicroUSB cable to the USB Power Supply, and plug the USB power supply into the power strip at the center of your table.

21 Let us set up our computersPlease wait about 30 seconds for your Raspberry Pi to boot up. If it does not boot, please raise your hand now, and someone will come over and help you fix the problem.

22 Our Computer’s Operating SystemOur computer runs Rasbian, a operating system based off of Linux Linux is open source: meaning the code is open to anyone to change Windows and Apple are both proprietary operating systems

23 Power up your device and let us open PythonOpen the program python3(IDLE3)

24 What can this thing do… Calculate the summation of your two favorite numbers

25 What can this thing do… Calculate the summation of your two favorite numbers Calculate the product of your two favorite numbers

26 What can this thing do… Calculate the summation of your two favorite numbers Calculate the product of your two favorite numbers Calculate the quotient of your two favorite numbers

27 What can this thing do… Calculate the summation of your two favorite numbers Calculate the product of your two favorite numbers Calculate the quotient of your two favorite numbers

28 What can this thing do… Calculate the summation of your two favorite numbers Calculate the product of your two favorite numbers Calculate the quotient of your two favorite numbers See if your computer has the infamous answer to

29 What can this thing do… Calculate the summation of your two favorite numbers Calculate the product of your two favorite numbers Calculate the quotient of your two favorite numbers See if your computer has the infamous answer to See if your computer can take a product of two gigantic numbers!

30 Wow you just showed me the world’s most bulky calculator, what else can I do…Let us define variables… Let us define our favorite numbers as our name. Example: Ryan = 3 Now calculate the summation, product and quotient of your numbers using variables. Try to change your favorite number Ryan = 4

31 Wow you just showed me the world’s most bulky calculator, what else can I do…Let us define variables… Let us define our favorite numbers as our name. Example: Ryan = 3

32 Wow you just showed me the world’s most bulky calculator, what else can I do…Let us define variables… Let us define our favorite numbers as our name. Example: Ryan = 3 Now calculate the summation, product and quotient of your numbers using variables.

33 Wow you just showed me the world’s most bulky calculator, what else can I do…Let us define variables… Let us define our favorite numbers as our name. Example: Ryan = 3 Now calculate the summation, product and quotient of your numbers using variables. Try to change your favorite number Ryan = 4

34 More complicated Functions.Ok so now let’s do something a little more interesting: Calculate Quadratic Equation. Recall, when we have 𝑦 𝑥 =𝑎 𝑥 2 +𝑏𝑥+𝑐 the roots of the equation are at 𝑥= −𝑏 ± 𝑏 2 −4𝑎𝑐 2𝑎 . Let us use Python get the larger root of 𝑦= 𝑥 2 +60𝑥+5.

35 Where is the Square Root Key?There is no square root key so how should we calculate it:

36 Where is the Square Root Key?There is no square root key so how should we calculate it: Use the keys we currently have and calculate square root another way, possibly newton’s method?

37 Where is the Square Root Key?There is no square root key so how should we calculate it: Use the keys we currently have and calculate square root another way, possibly newton’s method? Maybe someone else has had this problem, so python must have solved it

38 Where is the Square Root Key?There is no square root key so how should we calculate it: Use the keys we currently have and calculate square root another way, possibly newton’s method? Maybe someone else has had this problem, so python must have solved it Function calls: we will use pow(base, power)

39 Ok that is useful, but I don’t want to type this in every time I want to get a root.You can redefine your variables and use the up arrow to recall a command Let’s race to calculate the following: 𝑦= 𝑥 2 +2𝑥+3 𝑦=6 𝑥 2 +21𝑥+4 𝑦=−2 𝑥 2 −2

40 Wow that is still a little too much work, I feel really lazyLet us define a function! We can call it “find upper root”. Defining a function:

41 Wow that is still a little too much work, I feel really lazyLet us define a function! We can call it “find upper root”. Defining a function: def Keyword that defines a function

42 Wow that is still a little too much work, I feel really lazyLet us define a function! We can call it “find upper root”. Defining a function: def findUpperRoot Name of my function, note: No spaces, and starts with letters

43 Wow that is still a little too much work, I feel really lazyLet us define a function! We can call it “find upper root”. Defining a function: def findUpperRoot(a, b, c) My Parameters, I want to give my function the values of a, b, and c. Note: between parenthesis and comma separated.

44 Wow that is still a little too much work, I feel really lazyLet us define a function! We can call it “find upper root”. Defining a function: def findUpperRoot(a, b, c): Special Character to say that, what I want findUpperRoot to do follows.

45 Wow that is still a little too much work, I feel really lazyLet us define a function! We can call it “find upper root”. Defining a function: def findUpperRoot(a, b, c): return Tab to tell the computer that this line is in the function

46 Wow that is still a little too much work, I feel really lazyLet us define a function! We can call it “find upper root”. Defining a function: def findUpperRoot(a, b, c): return Keyword that tells the function that it is giving the following value back to me.

47 Wow that is still a little too much work, I feel really lazyLet us define a function! We can call it “find upper root”. Defining a function: def findUpperRoot(a, b, c): return (-b + pow( b*b – 4 * a * c, .5))/(2 * a) Value the computer will calculate to return. Using the parameters we defined in

48 Let’s test it out! We can now debug using the following input:y= x 2 +60x+5

49 I made this cool function but… is it saved?Type quit() to quit from python. Enter python again by the python command Try your function call again by findUpperRoots(1, 60, 5)

50 Do you mean I have to this every time I want code!No, we will write a .py file, which is essentially a memory of what commands we wrote. We will use a program called idle to write make this file.

51 Using Vim, getting into vimWe can get into vim using the following command: vim Name of the program

52 Using Vim, getting into vimWe can get into vim using the following command: vim myFirstFile Name of the file I would like to open, note: It does not need to exist yet.

53 Using Vim, getting into vimWe can get into vim using the following command: vim myFirstFile.py Tells the computer that this file is in the python language

54 Inside VIM Three modes:Viewing mode: Mode you enter when you first enter the program, can only view the document, use the arrow keys to navigate Insertion mode Command mode

55 Inside VIM Three modes: Viewing modeInsertion mode: Enter this mode from viewing mode by pressing the ‘i’ key. In this mode you can change the document like any other document, use the arrow keys to navigate. Leave insertion mode by ‘esc’ key on top left of your keyboard Command mode

56 Inside VIM Three modes: Viewing mode Insertion modeCommand mode: Enter the command mode by typing ‘:’ in viewing mode to run commands. Only a couple commands we will use: ‘w’ : Write/save your work ‘wq’ : Write/save and quit the file ‘q!’ : quit without saving ‘esc’ : return to viewing mode without running a command

57 Creating .py in IDLE Go File -> New FileWe then get a new file, before we start lets save Go File -> Save as

58 Our first line of every programAt the top of every python program we should add the following line: #!/usr/bin/env python3 This tells the computer that it is operating system level

59 Our first line of every programAt the top of every python program we should add the following line: #!/usr/bin/env python3 Location of the python program that interprets our python language

60 Our first line of every programAt the top of every python program we should add the following line: #!/usr/bin/env python3 Name of the python program, we are looking for python 3, another common one is python 2

61 Ok so now let us make this functionSo now in vim add the function as follows: def findUpperRoot(a, b, c): return (-b + pow( b*b – 4 * a ... * c, .5))/(2 * a) Tells the computer that the next line is a continuation of this line

62 So now let us test this Run the program by run -> run module

63 Axis of symmetry radius radius

64 Let us make this a little more fancyLet us define a variable inside of the function, make the following change def findUpperRoot(a, b, c): discrim = b*b – 4 * a * c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return axis + radius

65 Let us make this a little more fancyLet us define a variable inside of the function, make the following change def findUpperRoot(a, b, c): discrim = b*b – 4 * a * c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return axis + radius Note: Tabs before all the lines in the function

66 Let us make this a little more fancyLet us define a variable inside of the function, make the following change def findUpperRoot(a, b, c): discrim = b*b – 4 * a * c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return axis + radius Defining the variables, note that we can use the variables in the lines following the declaration

67 Let us make this a little more fancyLet us define a variable inside of the function, make the following change def findUpperRoot(a, b, c): discrim = b*b – 4 * a * c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return axis + radius Returns the value of val

68 Sidenote We can return multiple values (called tuples) by:return val1, val2, val3 We then save these values using: val1, val2, val3 = test()

69 Now we have an upper root, we want both roots.We can return a list, an ordered sequence of numbers. Each number goes into a indexed bin. example = [32, 23, 23, 68] 32 23 23 68 1 2 3

70 Retrieving elements in a listThen to get the element out of each bin we use example The name of the list

71 Retrieving elements in a listThen to get the element out of each bin we use example[ ] Brackets to denote that we want to get an element

72 Retrieving elements in a listThen to get the element out of each bin we use example[1] The element we would like.

73 Retrieving elements in a listThen to get the element out of each bin we use example[1] 32 23 23 68 1 2 3

74 So now let us make the code return a list instead of a single elementdef findRoots(a, b, c): discrim = b*b – 4 * a * c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return [axis – radius, axis + radius] Brackets to denote that we want to return a list

75 So now let us make the code return a list instead of a single elementdef findRoots(a, b, c): discrim = b*b – 4 * a * c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return [axis – radius, axis + radius] Value of our 0th element

76 So now let us make the code return a list instead of a single elementdef findRoots(a, b, c): discrim = b*b – 4 * a * c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return [axis – radius, axis + radius] Comma to delimit we will have another element

77 So now let us make the code return a list instead of a single elementdef findRoots(a, b, c): discrim = b*b – 4 * a * c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return [axis – radius, axis + radius] Value of our one-th element

78 Boundary Case Let us try the following command to test our function findRoots(0, 1, 1) This would be to find the root for y=𝑥+1 We get an error…

79 Fixing the error ideologicallyWe want the following function: If a=0: −𝑐 𝑏 else: −𝑏+ 𝑏 2 −4𝑎𝑐 2𝑎

80 Let us code this: Original function: def findRoots(a, b, c):discrim = b*b – 4 * a * c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return [axis – radius, axis + radius]

81 Let us code this: If a is 0 the computer will otherwiseOur new If statement: def findRoots (a, b, c): if a == 0: return [–c / b] else: discrim = b*b – 4 * a * c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return [axis – radius, axis + radius] If a is 0 the computer will otherwise

82 Let us code this: This statement is a conditional statementOur new If statement: def findRoots (a, b, c): if a == 0: return [-c / b] else: discrim = b*b – 4 * a * c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return [axis – radius, axis + radius] This statement is a conditional statement

83 Other conditional statementsSyntax What is does == Checks if the values are equal < If the first value is less than the second > Likewise <= If the first value is less than or equal the second >=

84 Let us code this: Our new If statement: def findRoots(a, b, c): if a == 0: return [-c / b] else: discrim = b*b – 4 * a * c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return [axis – radius, axis + radius] Keyword says we will do the next block if we don’t do the previous block

85 Another boundary case Now try the call findRoots(0, 0, 3)We need to make a condition for b equaling 0

86 We can account for this with another if statementdef findRoots(a, b, c): if a == 0: if b == 0: if c == 0: return [float("inf")] else: return [] return [-c / b] discrim = b*b - 4*a*c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return [axis - radius, axis + radius] The code to handle b being 0

87 The actions of a nested ifdef findRoots(a, b, c): if a == 0: if b == 0: if c == 0: return [float("inf")] else: return [] return [-c / b] discrim = b*b - 4*a*c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return [axis - radius, axis + radius] If b is 0 the computer will otherwise

88 The actions of a nested ifdef findRoots(a, b, c): if a == 0: if b == 0: if c == 0: return [float("inf")] else: return [] return [-c / b] discrim = b*b - 4*a*c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return [axis - radius, axis + radius] If c is 0 the computer will otherwise

89 The actions of a nested ifdef findRoots(a, b, c): if a == 0: if b == 0: if c == 0: return [float("inf")] else: return [] return [-c / b] discrim = b*b - 4*a*c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return [axis - radius, axis + radius] The return value is a list of one element

90 The actions of a nested ifdef findRoots(a, b, c): if a == 0: if b == 0: if c == 0: return [float("inf")] else: return [] return [-c / b] discrim = b*b - 4*a*c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return [axis - radius, axis + radius] The value of the element is of type float

91 The actions of a nested ifdef findRoots(a, b, c): if a == 0: if b == 0: if c == 0: return [float("inf")] else: return [] return [-c / b] discrim = b*b - 4*a*c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return [axis - radius, axis + radius] The value of the element is infinity

92 The actions of a nested ifdef findRoots(a, b, c): if a == 0: if b == 0: if c == 0: return [float("inf")] else: return [] return [-c / b] discrim = b*b - 4*a*c denom = 2 * a axis = -b / denom radius = pow(discrim, .5) / denom return [axis - radius, axis + radius] The return value is an empty list

93 Testing time Now test on the following inputs:𝑦= 𝑥 2 +2𝑥+1 𝑦=5 𝑥 𝑥−4 𝑦= 𝑥 2 𝑦=3 𝑦=−2𝑥+4

94 Defining a new functionOur prompting function def prompt(): We will define a function prompt with no arguments

95 Creating a variable to hold user inputOur prompting function def prompt(): a = It will create a variable a

96 Creating a variable to hold user inputOur prompting function def prompt(): a = float( The value of a will be of type float

97 Creating a variable to hold user inputOur prompting function def prompt(): a = float(input( The value of a will be an input from the console

98 Creating a variable to hold user inputOur prompting function def prompt(): a = float(input(‘Number of x squared\’s:’)) The user will be prompted with the string Number of x squared’s

99 Creating a variable to hold user inputOur prompting function def prompt(): a = float(input(‘Number of x squared\’s:’)) The apostrophe will denote the beginning of the string

100 Creating a variable to hold user inputOur prompting function def prompt(): a = float(input(‘Number of x squared\’s:’)) The value of the string is inside

101 Creating a variable to hold user inputOur prompting function def prompt(): a = float(input(‘Number of x squared\’s:’)) The \ character is a special character telling the computer we want a ‘ character and don’t want to end the string

102 Special Characters in a stringCharacter sequence Value \\ \ \’ ‘ \n New Line \t Tab

103 Creating a variable to hold user inputOur prompting function def prompt(): a = float(input(‘Number of x squared\’s: ’)) b = float(input(‘Number of x\’s: ’)) c = float(input(‘Number of one\’s: ’)) We will do likewise for the values of a, b and c

104 Calculating our roots Our prompting functiondef prompt(): a = float(input(‘Number of x squared\’s: ’)) b = float(input(‘Number of x\’s: ’)) c = float(input(‘Number of one\’s: ’)) roots = findRoots(a, b, c) We will call our function to find our roots, and store the list as roots

105 Printing our results to the userOur prompting function def prompt(): a = float(input(‘Number of x squared\’s: ’)) b = float(input(‘Number of x\’s: ’)) c = float(input(‘Number of one\’s: ’)) roots = findRoots(a, b, c) print(roots) Finally print the value of the roots we found

106 Let us make it look a little betterLet’s make the output for each root a little nicer looking Let us make it so that for each root we print A root is ________

107 Properties of a for loopWe will add for root in roots: print(‘A root is {0:.3f}.’.format(root)) Keyword for to start a for loop

108 Properties of a for loopWe will add for root in roots: print(‘A root is {0:.3f}.’.format(root)) Creating a variable call root that will sequentially take all the value for each element in root

109 Properties of a for loopWe will add for root in roots: print(‘A root is {0:.3f}.’.format(root)) Keyword in

110 Properties of a for loopWe will add for root in roots: print(‘A root is {0:.3f}.’.format(root)) Specifying the list we will iterate on

111 Properties of a for loopWe will add for root in roots: print(‘A root is {0:.3f}.’.format(root)) Body of the for loop

112 Properties of a for loopWe will add for root in roots: print(‘A root is {0:.3f}.’.format(root)) We are going to print

113 Properties of a for loopWe will add for root in roots: print(‘A root is {0:.3f}.’.format(root)) The string we are going to print

114 Formatting a string We will addfor root in roots: print(‘A root is {0:.3f}.’.format(root)) We are going to format the string, by putting root into it.

115 Formatting a string We will add The bracket begins the replacementfor root in roots: print(‘A root is {0:.3f}.’.format(root)) The bracket begins the replacement

116 Formatting a string We will addfor root in roots: print(‘A root is {0:.3f}.’.format(root)) The 0th parameter passed into the format method will be placed here

117 Formatting a string We will addfor root in roots: print(‘A root is {0:.3f}.’.format(root)) The colon begins the format part of the replacement

118 Formatting a string We will addfor root in roots: print(‘A root is {0:.3f}.’.format(root)) The format is, any number of numbers in front of the decimal point, and at most 3 after the decimal point

119 Formatting a string We will add It is expecting to format a float.for root in roots: print(‘A root is {0:.3f}.’.format(root)) It is expecting to format a float.

120 Final Product Our new function: def prompt():a = float(input(‘Number of x squared\’s: ’)) b = float(input(‘Number of x\’s: ’)) c = float(input(‘Number of one\’s: ’)) roots = findRoots(a, b, c) for root in roots: print(‘A root is {0:.3f}.’.format(root))

121 More Testing Let us test on the following input− 𝑥 2 +3𝑥+4 4 𝑥 2 +5𝑥−3

122 Let us try a more complex polynomialNow let us try 𝑥 2 +1

123 Let us try a linear equation𝑥=1

124 Let us make the boundary cases have better print outsLet us print, There are no roots. If there are no roots, that is the size of roots is 0

125 Checking if we have a boundary caseThe new addition of code if Beginning of the if statement.

126 Checking if we have a boundary caseThe new addition of code if len(roots) == 0: The length of the list roots.

127 Checking if we have a boundary caseThe new addition of code if len(roots) == 0: Equals 0

128 Printing we have no rootsThe new addition of code if len(roots) == 0: print(‘There are no roots.’) We will print ‘There are no roots.’

129 Our new function Our whole function now: def prompt():a = float(input(‘Number of x squared\’s: ’)) b = float(input(‘Number of x\’s: ’)) c = float(input(‘Number of one\’s: ’)) roots = findRoots(a, b, c) if len(roots) == 0: print(‘There are no roots’) else: for root in roots: print(‘A root is {0:.3f}.’.format(root))

130 Let us try these Now let us try to solve 0=3 0=0

131 Infinite case When we have infinite solutions we want to print:There are infinite solutions.

132 Checking and printing infinite caseWe could make the change if len(roots) == 0: print(‘There are no roots’) else: if roots[0] == float(‘inf’): print(‘There are infinite solutions’) for root in roots: print(‘A root is {0:.3f}.’.format(root)) If the roots 0th element is infinity, we print ‘there are infinite roots

133 Checking and printing infinite caseBut we can make this simpler if len(roots) == 0: print(‘There are no roots’) elif roots[0] == float(‘inf’): print(‘There are infinite solutions’) else: for root in roots: print(‘A root is {0:.3f}.’.format(root)) The elif keyword is equivalent to an if statement in an else statement.

134 More Testing Test by solving 0=0

135 I wish we could have more mathLet us now make this program prompt for more equations while the user still has more things to enter. We will make a new method.

136 A new function This new function will be called run def run():The function run will have no parameters

137 Creating a flag This new function will be called run def run(): cWe will define a variable c that will represent the character the user enters

138 Checking if the user wants to run againThis new function will be called run def run(): c while c == ‘y’: The keyword while will start a while loop, which runs the body while the conditional is true

139 Initializing our flag This new function will be called run def run():c = ‘y’ while c == ‘y’: We want to evaluate the loop atleast once so we will initialize c as ‘y’

140 Prompting the user This new function will be called run def run():c = ‘y’ while c == ‘y’: prompt() We first want to prompt the user for an equation and solve it

141 Asking the user if they would like to go againThis new function will be called run def run(): c = ‘y’ while c == ‘y’: prompt() c = input(‘Would you like to\ enter another input? Enter y or n: ‘) Then we want to ask the user if they would like to enter another equation. Setting c to ‘y’ or ‘n’

142 This line is pretty long…This new function will be called run def run(): c = ‘y’ while c == ‘y’: prompt() c = input(‘Would you like to\ enter another input? Enter y or n: ‘) Notice that the single line of code is on two lines. Use the ‘\’ to line break a long line of code.

143 Our new function This new function will be called run def run():c = ‘y’ while c == ‘y’: prompt() c = input(‘Would you like to\ enter another input? Enter y or n: ‘)

144 MORE TESTING! Let us test our new function.

145 What if we have a cheeky userNote that we do not check to make sure the user only enter y or n. Let us continue asking until the user does that.

146 A new form of while loop This new function will be called run def run(): c = ‘y’ while c == ‘y’: prompt() while True: c = input(‘Would you like to\ enter another input? Enter y or n: ‘) if c == ‘y’ or c == ‘n’: break We add an infinite loop with the following body

147 A new form of while loop This new function will be called run def run(): c = ‘y’ while c == ‘y’: prompt() while True: c = input(‘Would you like to\ enter another input? Enter y or n: ‘) if c == ‘y’ or c == ‘n’: break First ask the user for their input just as before

148 A new form of while loop This new function will be called run def run(): c = ‘y’ while c == ‘y’: prompt() while True: c = input(‘Would you like to\ enter another input? Enter y or n: ‘) if c == ‘y’ or c == ‘n’: break Then if c equals y or n, we break out of infinite loop using the break keyword

149 Making our computer talkLet us make this so that the raspberry pi talks to us. We do not know how to directly do this but I bet someone else has figured it out We are going to use both what is in the operating system and import other code to make our code a lot better.

150 Importing other programsWe will add the following line to the top of our file to tell the computer to import other files import os, time

151 Running other program We will now make a function that makes the operating system speak a string, and print it out to the operating system.

152 Creating a function to make the computer talkOur speak function def speak(str): os.system(‘espeak \‘ ‘ + str + ‘ \‘ ‘) The function speak will have one parameter, our string

153 Running a command Our speak function def speak(str): os.system(‘espeak \‘ ‘ + str + ‘ \‘ ‘) First we call the os, to run a command, which is passed as a string

154 Running a command We are running the program espeak on the string, strOur speak function def speak(str): os.system(‘espeak \‘ ‘ + str + ‘ \‘ ‘) We are running the program espeak on the string, str

155 Running a command We then make the computer speak by adding the command speak, with the same parameters, before all our print and input function calls.

156 Free Resources If you wanted to continue your studies try these three free resources: https://www.codecademy.com/ https://docs.python.org/3/tutorial/index.html https://www.raspberrypi.org/resources/ https://repl.it/ https://www.python.org/