 # Predefined functions

## Learning Intentions

• Understand the term 'predefined function'

• Identify and use appropriate predefined functions

## Success Criteria

• Be able to explain the term predefined function
• Be able to identify and describe the predefined functions specified at National 5 level

## Predefined functions

• A pre-defined function carries out an operation or calculation using the data we give (pass) it and returns a single value.  The functions listed below are relevant to the course content for National 5:
• Round
• Length
• Random
• The SQA sometimes refers to built-in object functions as predefined functions, when in actual fact they are not. If you want to find out more about this, look up object methods in Python.

## National 5

• At National 5 you looked at the following predefined function:

• Random

• Round

• Length

## Random

• The random predefined function generates a random number between a range in Python:

``````import random

#Generates a number between 10 and 100
print(random.randint(10, 100))``````

## Round

• The round function rounds a number to a specified number of decimal places.

``````x = 3.145

#Will give us 3.15
print(round(x, 2))

#Will give us 3.0
print(round(x, 0))``````

## Length

• The length function is used to calculate the length of an array.

``````fib = [1, 2, 3, 5, 8, 13, 21, 34, 55, 89]
#Should print 10
print (len(fib))``````

## lower and upper

• The lower and upper functions turn a string to lowercase or uppercase.

``````x = "John"
y = x.lower()
z = x.upper()

print(y)
print(z)``````

In your jotter, write down an example of how each of the predefined function shown before could be used in Python

Presentation Overview
National 5 Computer Science :: Software Design and Development :: Predefined Functions