Python Development Lesson 1 - JM Lesson Obs

• LessonUp
• Lower Secondary (Key Stage 3)

Python Development Lesson 1

What is programming?

What is Syntax?

Common 'Syntax' Errors

The most common Syntax errors are:

• missing a comma, colon, quotation mark, or misspelling a word.

KO: To be-able to debug and fix errors in code.

All

•  To use the 'Syntax' of Python to identify errors in a line of code.

Most

• To explain what a 'Variable' is and how they are used in coding.
• To explain what a 'Selection' statement is and how they are used in coding.

Some 

• To demonstrate and use a 'Variable' in some code.
• To demonstrate and use a 'Selection' statement in some code.

Code that runs one line after another is known as coding in...

1. Sequence
2. Selection
3. Iteration
4. Recursion

Code that only runs when a condition is met is known as coding in...

1. Sequence
2. Selection
3. Iteration
4. Recursion

Code that repeats/loops is known as coding in...

1. Sequence
2. Selection
3. Iteration
4. Recursion

print statement

Think back to Year 7 and Year 8.

Can you remember how to create a print statement in Python?

If you're not sure, discuss with the person next to you...

Click here to code.

What is an output?

A message outputted to the user (like on screen).

Here are some examples of different outputs in Python:

print ("Dave")                - the word "Dave" would be output

print(6)                            - the number 6 would be output

print(name)                   - the value stored in the variable would be output

print(7*3)                       - would print out 21 as it performs the sum first

Point out that text needs quotes and number do not need them

What is a Variable?

An area in memory used to store a value the program will use.

The value can change.

Here are some examples of Variables in Python

name = "Dave"                      - Text 

health = 100                           - Integer

discount = False                  - Boolean  (True/False)

Inputs

We can use variables to store inputs from the user.

In Python we use input

input ("Question the user will see as a prompt")

So to store a name we would use:

name = input ("What is your name  ? -->  ")

Python Refresh STAGE 1

The simplest skill to refresh is outputs and variables

in python this is printing.

CLICK HERE to see the example

CLICK HERE to try a challenge

DO extra demos where necessary

Challenge

Using what we have learnt so far in pairs, I want you to create a sentence, using 2 variables. You must ask the user for their input.

You have written a program that stores a name in a variable and prints a greeting using that variable. Which is correct code for this

1. Print(Hello,"name")
2. print(Hello,"name")
3. print("Hello",name)
4. print("hello","name")

CORRECT

CAUSE AN ERROR

print = ("Hello")

Print("Yes!")

print("this one)

name = imput("what is your name")

name = input("what is your name")

print("this text")

fav colour = "Green"

age = 10

print("Hello", name)

print("Bye",name")

Python Refresh STAGE 2

Now we will refresh the conditional (selections) in coding

This is the use of IF/ELIF and ELSE

CLICK HERE to see some examples

CLICK HERE to try some challenges

In python you must write IF, ELIF and ELSE in capital letters

1. TRUE
2. FALSE

After every if, elif and else statement you put ...

1. ;
2. }
3. :
4. #

An elif part of the code will only run if the if part was not met

1. True
2. False

an if statement must always have an else component

1. True
2. False

which of the following if statements would cause an error

1. if name != "Fred":
2. if password == guess:
3. if name = "Bobby":
4. if age >= 18 :

In your own words: What is a 'Selection' statement?

Plenary 

To show me your understanding, I want you to create a short program. Click here

  You must:

• Ask the user for their input.
• Use selection statements with if, elif and else.
• You must use print statements.

CheckPoint

You should be happy with the following terms and how to code them in Python:

• printing outputs
• setting variables (with or without and input from user)
• using If, elif and else properly 
• can explain the difference in using if, elif and else
• IF YOU DO NOT understand these then tell your teacher

Looping code

Sometimes you need the computer to repeat steps until something happens (a condition being met)

In Python we can use either while or for loops

Lets look at each in turn

While loops

While loops will repeat until a condition is met

CLICK THIS to see some examples

CLICK THIS for a challenge use while loops

Which symbol will check is two values are the same in a while condition?

1. !=
2. ==
3. =
4. "="

Which symbol will check is two values DO NOT equal each other

1. !=
2. NOT=
3. ¬=
4. =/=

What would this code do when run:
x=1
while x != 10:
print(x)

1. Count to 10 on screen
2. Count to 9 on screen
3. print the value 1 over and over forever
4. produce a syntax error

For loops

For loops repeat code a set amount of times and are not waiting on a condition to be met.

CLICK THIS to see some examples and tweak it where asked.

What is the output of this for loop in python:
for i in range(3):
print(i)

1. 0 1 2
2. 0 1 2 3
3. 3
4. iii

When should you use a for loop instead of a while loop?

1. When the loop has to run indefinitely
2. When the loop involves complex logic
3. when we need a variable
4. When you know the number of iterations

Link Summary

CLICK HERE - Input/output recap

CLICK HERE - Input/output tasks

CLICK HERE - IF/ELIF/ELSE recap

CLICK HERE - IF/ELIF/ELSE tasks

CLICK HERE - While loop recap

CLICK HERE - While loop tasks

CLICK HERE - For loop recap and task

What is a variable?