Input & Output
Coding: Introduction to Python v3, topic 1.2.1
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 combine non-string data with text, we must first cast it to a string.
- Otherwise, print() can display non-string data directly.
Test yourself on Input & Output
What is the most common input device for command line programs?
What data type is keyboard input?
Data can only be input from a keyboard. True or false?
How are outputs usually delivered in a command line program?
Why are output statements used?