Input & Output

Test yourself

Input

There must be some mechanism for the user to input data to the computer.

What data can I input?

Data can be input from any device connected to the computer.
The keyboard is the most common data input device for command line programs.
We will only look at keyboard input in this course.

The input function

Python has a built in function (command) which allows us to take keyboard input.
We can use the code: input(“Prompt”) to take the input.
We can write any text for the “Prompt”, which will be displayed to the user before they type their response.
A prompt is a message that is displayed to the user before they type their response.

Data type of input

When data is entered from the keyboard, it is automatically a ‘string’.
A string is a sequence of character inputs from the keyboard, for example ‘Hello’.

Output

Output is necessary so that we can see the results of programs.

Why do we need outputs?

Outputs are important so that we can communicate the result of a program to the user.
Outputs are usually delivered as text onto the screen.

The print function

The output function in Python is called ‘print’.
The output function ‘prints’ data onto the screen.
- E.g. print(“Hello, world!”) would output the text “Hello, World!”.

What data can be outputted?

Output data must be a string before we can print it.
If we want to display data that is not a string, then we must first cast it to a string.

1Introduction to Python

1.1Python

1.1.1Python

1.2Input & Output

1.2.1Input & Output

1.3Data Types

1.3.1Data Types

1.4Variables & Constants

1.4.1Variables & Constants

1.5Operators

1.5.1Arithmetic & Relational Operators

1.5.2Boolean & Assignment Operators 2

1.6Program Flow

1.6.1Selection

1.6.2Iteration

2Data Structures

2.1Lists & Strings

2.1.1Lists

2.1.2Strings

2.2File Handling

2.2.1File Handling

3Modularity

3.1Subroutines

3.1.1Subroutines

3.2Data Flow

3.2.1Data Flow

4Good Practice

4.1Naming & Whitespace

4.1.1Identifiers

4.1.2Whitespace

4.2Comments

4.2.1Comments

4.3Exceptions

4.3.1Exceptions

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