Check your understanding of the previous reading: recognising function and method calls, and predicting the results of calling functions and methods with arguments.

Question 1

Mark all of the following that are valid function or method calls. Do not worry about whether a variable actually exists — only determine whether 1) this is a function or method call, and 2) the syntax is valid.

Select every one that qualifies, then check.

list.pop()
Correct. A value, then a dot, then a name, then parentheses — that is a valid method call.
.open()
Not quite. A line cannot start with a bare dot — there is no value in front of it to call the method on, so this is not valid syntax at all.
fire
Not quite. Without parentheses this is just a name being referenced, not called.
build(1, 2, 3)
Correct. A name followed by parentheses is a valid function call, here with three arguments.
a = 0
Not quite. This is an assignment statement — no parentheses, so no call is happening.
print()
Correct. A name followed by parentheses, this time with zero arguments — still a valid function call.
"help"()
Correct, by the question's own rule: a value followed by parentheses is call syntax, and the syntax here is valid. (It would actually crash if you ran it, since a string is not something you can call — but the question asks you to ignore that and judge the syntax.)
"harry potter".title()
Correct. A string literal, a dot, a method name, and parentheses — a valid method call.

Question 2

Identify whether each of the following is a method call or a function call.

list.append()

Method call — it has a calling value (list), a dot, then the name and parentheses.

print()

function.call()

Method call — despite the confusing names, the dot makes this a method call on the value function.

method()

"function".method()

Question 3

How would you call a function named openDoor? Assume it takes no arguments.

Show worked solution

A function call needs the function's name immediately followed by parentheses. Since openDoor takes no arguments, the parentheses stay empty: openDoor().

Question 4

The function makeCat below returns the string "Cat". What value will the variable x hold after this line runs?

x = makeCat() + makeCat() + makeCat()

Show worked solution

Each call to makeCat() is replaced by the string "Cat". The + operator on strings concatenates them, so "Cat" + "Cat" + "Cat" evaluates to "CatCatCat".

Question 5

The function add5 below returns the number 5 added to its argument. What value will the variable x hold after this line runs?

x = add5(10) * add5(2)

Show worked solution

add5(10) returns 15, and add5(2) returns 7. Multiplying them: 15 * 7 = 105.

Question 6

True or False: Functions are reusable chunks of code that have inputs and outputs.

Select one answer, then check.

True
Correct. Functions take arguments as input, process them, and can return a value as output — and once written, they can be reused wherever they're needed.
False
Not quite. This is exactly what a function is: a reusable chunk of code with inputs (arguments) and outputs (a return value).