Category: National 4

Incrementing Counter

This is a programming statement which increases by a known amount, each time it is called.

  • Score=Score+1
  • One=One+1
  • Bonus=Bonus+10

Incrementing counters are often used inside loops to keep track of the number of iterations.

counter

In the example above the tries=tries+1 line is keeping track of how many times the loop has been iterated.

Python Selection – if:

diceToday we investigated the use of the if statement, this is a selection statement which allows Python to make choices.

We have updated our dice roll program from last time to include a for loop and multiple if statements. The program now displays a summary of the results of 1000 dice rolls.

For homework the class were asked to TRACS the program and we will discuss how efficient it is next time.

3G JPEG Investigation

Today the class carried out an investigation into the JPEG image compression technique.  The pupils were tasked with finding out.

  • Why we use JPEG compression on images?
  • How does JPEG compression work?
  • What is JPEG good at?
  • What is JPEG bad at?
  • When would we use JPEG compression?

The Pupils had to report on a powerpoint slide and include an example of a good and bad use of JPEG.

Read more

Python Functions

A function is a predefined block of code which is used then programming. It often contains a number of commands and steps.

Here are some of the functions we have met

print()

This function displays the string that is contained in it parenthesis ().

print(‘Hi there, how are you?)

input()

This function displays the string in its parenthesis but allows the user to enter a string that is then returned and assigned to a variable.

age=input(‘What is your age?’)

str()

Converts the contents of its parenthesis to a string

check=input(‘Is your age ‘+str(age))

len()

Outputs the length (number of characters) of a string or the size (number of elements) in an array

print(‘The length of your name is’,len(name))

float()

Converts a value to a floating point number

weight=float(input(‘How many KG do you weight’))

int()

Converts a value to an integer

age=int(input(‘What is your age?’))

 

Python – Input()

Python input() function returns a string to the assigned variable. This can cause us problems when we want to store integers or floats.

We can use the int() function to convert the string to a integer or the float() function to convert it to a floating point. It is better to do this when you get the input or initialise the variable as you may forget later in the program.

InputInt
The first block of code shows Python returning a string. The second block of code uses a int() to return an Integer

 

Scratch – Calculations using a loop

Today we recapped performing calculation within and using a loop. We started off redoing the 6 times table task, before improving it to display all the times tables from 1 to 10.

TimesTable

We then created a program that took in 4 ages and displayed the total only using one user created variable

Age

These two programs make use of loops to reduce the number of programming lines, this making the program more efficient.