Try typing the following in the Python shell and press return after each calculation. Write the answer the program displays next to the sums below.

Transcription

1 Name: Date: Instructions: PYTHON - INTRODUCTORY TASKS Open Idle (the program we will be using to write our Python codes). We can use the following code in Python to work out numeracy calculations. Try typing the following in the Python shell and press return after each calculation. Write the answer the program displays next to the sums below *9 30/6 Tick here if you managed to do it Instructions: Next, select File > New Window to create a window which you can code into and save Click File > Save and name the file helloworld.py (make sure you ve saved it to an appropriate location - ask your teacher if you are unsure). Practice task - when using the statement print programs will display the text within the quotation marks. Try this by writing the following code:

2 print ( Hello world! ) TIP: Python is case sensitive so check you have used a lower case letter p! If using version of Python 3.3 or later you must use brackets after the print command. Run a simple hello world program by selecting Run then Run Module. TIP: Remember to run a program you must first save the changes you ve made to your file. NOTE: The program will run in the outer Python window we used earlier (the Python shell). If you have typed the code correctly the program will display the words Hello World! Tick here if you managed to do it Well done you have written your first Python program! Can you write a program which displays longer text and on different lines? For example: Hello, how are you today? I hope you are enjoying this lesson. What shall we code next in Python? TIP: Use the print statement on each new line to display text over several lines Tick here if you managed to do it

3 Name: Date: Instructions - Declaring variables: Variables may be thought of as boxes within our program where we can place data (numbers or text). We can then use the contents of the boxes within our program and the values assigned to our variable may change as our program runs. When we create a variable and assign data (get a box and put something in it) it is called declaring a variable. To declare a variable we use the following code for example: variable1 = 6 In this example above we have created a variable called variable1 and given it the value of 6. We can create more than one variable and we can assign text as well as numbers to variables e.g. name = John score = 6 PYTHON - TASK SHEET 2 Q. What are the 2 variables that I have created using the code above? Q. What is the value of each variable? Your teacher will now reveal the two answers. Tick here if you got them correct Instructions - Assigning variables: Now create a new Python file called variables.py a) Create a variable called dogs with a value of 12 and a variable called

4 biscuits with a value of 3. We will be using these variables to write a program that calculates the total number of biscuits required to give x number of biscuits to x number of dogs. Your teacher will now reveal what you should have typed. Tick here if you got it correct Instructions - Comments A comment is a line of code that isn t part of the program but is there to explain to the programmer what parts of the code are doing. We write comments in regular English (or whatever language we as programmers may speak) as opposed to the language of Python. Comments are important as when we write longer pieces of code we may forget the function of different parts, or we may work on code with others and therefore we need to explain what we are doing. However, the trouble with writing in regular English within our program is that our computer thinks we are still writing in Python and may try and interpret commands from what we have said. As such, we need to indicate when we are writing a comment and we do that by using #. The computer will ignore any line starting with # as it knows this is a comment to the programmer and not part of the code. b) Can you now add a comment, using the # symbol for the player and points variables you have created to add an explanation about what we are coding? Your teacher will now reveal what you should have typed. Tick here if you got it correct Instructions - Using mathematical operations and print statement with variables: Task: The purpose of this program is to work out the total number of biscuits required based on the two variables we have declared: the number of dogs and the number of biscuits they each get. To write the program to calculate this, add the following code beneath your variables and comments total = dogs*biscuits print total c) Q. What new variable is being declared? Q. What is the name of this new variable? Q. What mathematical operation can you see here? Q. How would you explain this section of code, what is it asking the computer to do? Q. What do you expect the output of this program to be?

5 d) Now save your program and select Run then Run Module. Remember, the window you have been coding in will close and your program will run in the outer Python window we used earlier. If you have entered the code correctly your program will display the total number of biscuits required for all dogs - 36 Tick here if you have achieved this Extension: Practice editing your program by changing the values for the two variables. TIP: To modify your program you should return to the window it was written in and make changes before selecting Save then Run then Run Module.. a) Can you write a program to calculate the number of biscuits needed for a children s party if there are 30 children and they each get 4 biscuits each? Tick here if you have achieved this b) Can you write a program to calculate the total number of points 4 teams got in a tournament. Choose your own numbers for how many points each team got! Tick here if you have achieved this c) 5 students make 420 by selling their products. Their total costs were 100. Write a program to calculate how much money they make each after they have paid their costs. Tick here if you have achieved this

6 Name: PYTHON - TASK SHEET 3 Date: Python has statements, which can be used to accept an input of data from the user. The data which is entered can be used to declare variables. So in other words, rather than saying what the value of the variable is, we can ask the user to enter the data instead. For example, you could type in the following code: name = input ("hello, please enter your name: ) print ("hello, nice to meet you " +name) (Tip: I ve left a space before the last quotation mark to give the user space to enter their name). Q. What do expect to happen when this program is run? Now try running the program and see what happens. Q. What happens? Was your prediction correct? YES/NO TASK: Now try programming a different question which requires the user to input text data, such as the one below. age = input ("how old are you? ") print ("wow you are " +age) Write your own similar code below. Then when you are happy with it type it into Idle and select Save (you could save it as input.py) then select - Run - Run Module. TIP: Just like the example above, make sure; a) The question is inside quotation marks b) The question is also inside brackets Tick here if your program ran correctly

7 Inputs and mathematical operations: You are now going to write a program which will: 1. Allow the user to enter the number of children in a class 2. Allow the user to enter the number of house points they require each 3. Output the total number of house points required. TASK: Jot down below how you could tackle this coding problem. TIP 1: When typing in the maths calculation you want Python to do, you will need to declare that these are numbers (intergers), otherwise it will recognise them as text (a string) and it won t work. Here is an example children = input ("how many children are there?") sweets = input ("how many sweets do they want?") total= int(children)*int(sweets) print (total, is the number of sweets you will need ) TIP 2: Remember if you want the user to type something in you must use the code =Input ( ) TIP 3: Remember to use # symbol for comment lines (this is to help you or others and doesn t form part of the program). IDEAS - jot your solution ideas below Now try running the program. Q. Is the user asked for the number of children and the number of house points each child requires before the program then outputs the total number of house points required? YES/NO TASK 1: Can you write a program which asks the user to enter how many children are in a class and how many children are in each group? The program should then output how many whole groups there will be. TASK 2: Can you write a program that asks the user how many days there are until half term. You will need to input the right code so that the program output displays this in seconds?

8 Name: Date: PYTHON - TASK SHEET 4 Conditional statements What the code does sometimes depends on a condition being met or not met. These are called conditional statements (similar to using an if, else block in Scratch). The table below shows the syntax (python language) for comparison operators (what we are comparing the condition to). We will require these to work with our conditional statements. The short piece of code below uses conditional statements and comparison operators. Try inputting the code below into Idle and then save your program and select Run then Run Module #Declare name variable using input from user name = input ( Hi, What is your name? ) print ( It is lovely to meet you, +name) # Declare feeling variable using number input from user feeling = int (input ( How are you feeling today? Excited = 1, Happy = 2, Sad = 3 )) # Use conditional statement with equal to comparison to determine which response is given if feeling == 1: print ( Fantastic. I wonder what you re excited about? ) elif feeling == 2: print ( I am happy too. It s a great day! ) elif feeling == 3: print ( I am sorry to hear that you are miserable. How can I cheer you up?

9 TASK: In your own words, can you explain below how the above code works? Programming a calculator: Here is a second example which uses a range of comparison operators. In this example the user s inputs also cause the program to perform mathematical operations on the variables declared, like a calculator. Try inputting and running the following code in Idle num1 = input ( Please enter a number ) num2 = input ( Please enter a second number ) if num1 > 100: else: print ( Your first number is greater than 100 ) print ( Your first number is less than 100 ) if num2 > 100: else: print ( Your second number is greater than 100 ) print ( Your second number is less than 100 ) op = input ( Select an operation: 1. Add 2. Subtract 3. Multiply ) if op == 1: add = num1 + num2 print add elif op == 2: sub = num1 num2 print sub elif op == 3: mul = num1*num2 print mul

10 TASK: In your own, words write an explanation below of what is happening in this piece of code. TASK: Can you program a French dictionary that provides the user with a range of English words to choose from and returns the translation in French? Plan it out below.