Python Knowledge Check

What is the main version of Python currently supported?

• Python 1

• Python 2

• Python 3

Answer explanation

The currently supported version of Python is Python 3.

What Python function is used to display information on the screen?

• len

• print

• open

Answer explanation

len() = Returns the length of an object.
E.g. If the object is a string, len() will return the number of characters in the string.

If the object is a list, len() will return the number of items in the list.

print() = Displays the information on the screen.

open() = Opens a file and returns a file object.

What file extension is typically used for Python files?

• python

• p

• py

To show a string on the console, what code would you enter?

• print(my message)

• println("my message")

• print("my message")

Answer explanation

Use the print function with double quotation marks to show strings.

If you invoke a program with program.py 1 2, what does the code sys.argv[0] contain?

• It contains the program.py, the name of the program

• It contains 1, the first command-line argument.

• It contains 2, the second command-line argument.

Answer explanation

Position 0 (in sys.argv[0] is always the name of the program.

What will happen if you run the statement "1" + 2 ?

• It will evaluate to 3.

• It will give an error.

• It will become "12".

Answer explanation

It will show the error message "can only concatenate str (not "int") to str".

Under what conditions does a test expression that uses the and operator evaluate to True?

• A test expression that uses the and operator evaluates to True when both subexpressions are true.

• A test expression that uses the and operator evaluates to True when one subexpression is true and the other is false.

• A test expression that uses the and operator evaluates to True when both subexpressions are false.

Answer explanation

Both conditions in the test expression must be true for the entire test expression to evaluate to true.

What is the keyword elif short for in Python?

• else if

• only if

• else

Answer explanation

You can use the elif keyword to add multiple test expressions to your program.

What values in a test expression are always interpreted as false?

• Any non-zero values

• Empty

• None and 0

Answer explanation

None and 0 are interpreted as false in Python.

Are strings immutable?

• No, because they can be modified.

• Yes, because you can't modify them.

• No, because you can split them.

Answer explanation

The .split(' ') method, which includes the newline character, breaks strings into separate lines.