Arrays – Mutating Methods
Name:
Date:
Class:
A
Quick Questions
Shade in the A or B circle for each question.
1. Does push() add an element to the end of an array?
2. Does pop() remove the first element of an array?
3. Does unshift() add an element to the start of an array?
4. Does shift() remove the first element of an array?
5. Do these methods change the original array?
B
Match the Pairs
Draw a line connecting each item on the left to its match on the right.
| Left column | Right column | |
|---|---|---|
| 1nums.push(4) | Anums.unshift(1) | |
| 2nums.pop() | Bnums.shift() | |
| 3Adds an element to the start of an array | CAdds 4 to the end of the nums array | |
| 4Removes the first element from an array | DWrong - use pop(), not remove(), to remove the last element | |
| 5a.add(3); | EWrong - use push(), not add(), to add to the end | |
| 6b.remove(); | FRemoves the last element from the nums array |
C
Definitions
push()
D
Fill in the Blanks
Complete each line of code by filling in the missing parts.
1.
nums.____(4);
2.
nums.___();
3.
nums._______(1);
4.
let first = nums._____();
5.
scores.____(90);
E
Spot the Error
Shade in the letter of the line that contains an error.
Question 1
A
a.add(3);
B
let a = [1, 2];
C
console.log(a);
Question 2
A
let b = [1, 2, 3];
B
b.remove();
C
console.log(b);
Question 3
A
let c = [2, 3];
B
console.log(c);
C
c.push;
Question 4
A
let d = [1, 2, 3];
B
console.log(d);
C
let e2 = 5;
D
d.Pop();
Question 5
A
let e = [2, 3];
B
console.log(e);
C
let f2 = 1;
D
console.log(f2);
E
e.Push(1);
Answer Key
Arrays – Mutating Methods
Section A: Quick Questions
Q1
A — Yes
Q2
A — No
Q3
B — Yes
Q4
B — Yes
Q5
A — Yes
Section B: Match the Pairs
Q1
nums.push(4) → Adds 4 to the end of the nums array
Q2
nums.pop() → Removes the last element from the nums array
Q3
Adds an element to the start of an array → nums.unshift(1)
Q4
Removes the first element from an array → nums.shift()
Q5
a.add(3); → Wrong - use push(), not add(), to add to the end
Q6
b.remove(); → Wrong - use pop(), not remove(), to remove the last element
Section C: Definitions
Q1
push() — Adds one or more elements to the end of an array, changing the original array.Section D: Fill in the Blanks
Q1
nums.push(4);Q2
nums.pop();Q3
nums.unshift(1);Q4
let first = nums.shift();Q5
scores.push(90);Section E: Spot the Error
Q1
A — Use push(), not add(), to add to the end of an array.
Q2
B — Use pop(), not remove(), to remove the last element.
Q3
C — push() needs parentheses to actually call the method.
Q4
D — 'pop' must be lowercase - a capital P causes an error.
Q5
E — 'push' must be lowercase - a capital P causes an error.