Hello World

In this chapter you will:

area	topic
🚀	write a Hello World program in Python
💡	use the string data type
💡	call the functions print() and input()
⚙	store text in a string variable
🔧	enter Python commands
🔧	modify Python commands
🐞	find SyntaxErrors

Exercise 1: Your first Program

Create a new file in the editor window and enter the following instructions:

name = input("What is your name? ")
print("Hello", name)

Execute the program by pressing the “Execute” button or pressing F5 in Spyder. What happens?

Exercise 2: Break the program

When programming, it is inevitable that you make mistakes. Errors can be simple typos or complicated errors in the logical structure. One of the most important skills in programming is to find the cause of a bug in a program and fix it. You can practice this by intentionally breaking the program and seeing what happens.

Try the following programs with errors one by one and try to understand the error message:

name = input("What is your name? ")
pront("Hello", name)

name = input("What is your name? "
print("Hello", name)

name = input("What is your name? ")
print(Hello , name)

x = input("What is your name? ")
print("Hello", x)

How can you find out what is going on?

Exercise 3: input

Which of the following input commands work? Try them one by one.

name input("enter your name: ")

name = input("enter a number: ")

name = input(enter your name)

name = input()

Exercise 4: print

Which of the following print commands work? Try them one by one.

print "Hello"

print("Hello", name, name)

print("Hello" + name)

print("Hello name")

print(name)

Exercise 5: Variable names

Try which of the following names of Python variables can be used:

YODA = 'jedi'

darth vader = 'sith'

luke99 = 'jedi' = 'sith'

2000imperator = 'sith'

obi_wan_kenobi = 'jedi'

darth.maul = 'sith'

Exercise 6: Three little bugs

The following program should output a song by Bob Marley. It contains three bugs. Copy the code into your editor. Then find and fix the bugs.

part1 = "Don't worry about a thing"
part2 = "Cause every little thing"
part3 = gonna be all right

text = "part1 + part2 + part3"
print(text

Exercise 7

Write a program that asks for your first and last name and outputs both.

Reflection questions

• What is a function in Python?

• How can you recognize a function?

• What can you put inside the brackets of the print() function?

• What are legal/illegal variable names?

• What can you do if your program does not work?