Array operations (append, insert, remove) in Swift - Step-by-Step Execution

Concept Flow - Array operations (append, insert, remove)

Start with empty array

↓

Append element

→Array grows by 1 at end

↓

Insert element at index

→Shift elements right from index

↓

Remove element at index

→Shift elements left from index

↓

Array updated with changes

↓

End

This flow shows how an array starts empty, then elements are added at the end or inserted at a position, and elements can be removed by shifting others.

Execution Sample

Swift

var arr = [Int]()
arr.append(10)
arr.insert(5, at: 0)
arr.remove(at: 1)
print(arr)

This code creates an empty array, adds 10 at the end, inserts 5 at the start, removes the element at index 1, then prints the array.

Execution Table

Step	Operation	Array State	Index/Value	Action
1	Initialize	[]	-	Create empty array
2	Append	[10]	Value=10	Add 10 at end
3	Insert	[5, 10]	Value=5, Index=0	Insert 5 at index 0, shift 10 right
4	Remove	[5]	Index=1	Remove element at index 1 (10), shift left
5	Print	[5]	-	Output final array

💡 All operations done, array is [5]

Variable Tracker

Variable	Start	After Step 2	After Step 3	After Step 4	Final
arr	[]	[10]	[5, 10]	[5]	[5]

Key Moments - 3 Insights

Why does inserting at index 0 shift the existing elements?

Because arrays keep order, inserting at index 0 moves existing elements right to make space, as shown in step 3 of the execution_table.

What happens if we remove an element at an index?

The element at that index is removed and elements after it shift left to fill the gap, as seen in step 4 of the execution_table.

Why does append add the element at the end?

Append always adds to the end without shifting, growing the array size, shown in step 2 of the execution_table.

Visual Quiz - 3 Questions

Look at the execution_table, what is the array after step 3?

A [5]

B [10, 5]

C [5, 10]

D [10]

💡 Hint

Check the 'Array State' column at step 3 in the execution_table.

At which step does the array size decrease?

A Step 4

B Step 3

C Step 2

D Step 5

💡 Hint

Look for the step where an element is removed in the execution_table.

If we insert at index 1 instead of 0 in step 3, what would the array be?

A [5, 10]

B [10, 5]

C [10, 5, 10]

D [10]

💡 Hint

Think about where the new element goes and how existing elements shift.

Concept Snapshot

Array operations in Swift:
- append(value): adds value at the end
- insert(value, at: index): adds value at index, shifts right
- remove(at: index): removes element at index, shifts left
Arrays keep order and size changes accordingly.

Full Transcript

We start with an empty array. Append adds an element at the end, growing the array. Insert adds an element at a specific index and shifts existing elements right to keep order. Remove deletes an element at an index and shifts elements left to fill the gap. The final array reflects all these changes.