Array Functions

Common Pseudocode provides various functions and operations for working with arrays and lists.

Array Properties

length - Get Array Length

Returns the number of elements in an array.

Syntax:

count = length of array
count = array.length

Example:

numbers = [1, 2, 3, 4, 5]
count = length of numbers  // 5
count = numbers.length     // 5

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Adding Elements

append/push - Add Element to End

Adds an element to the end of an array.

Syntax:

append element to array
array.append(element)
array.push(element)

Example:

numbers = [1, 2, 3]
append 4 to numbers  // [1, 2, 3, 4]

fruits = ["apple", "banana"]
fruits.push("orange")  // ["apple", "banana", "orange"]

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insert - Insert Element at Position

Inserts an element at a specific index in an array.

Syntax:

insert element at index position in array
array.insert(position, element)

Example:

fruits = ["apple", "orange"]
insert "banana" at index 1 in fruits  // ["apple", "banana", "orange"]

numbers = [1, 3, 4]
numbers.insert(1, 2)  // [1, 2, 3, 4]

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Removing Elements

remove - Remove Element at Index

Removes an element from an array at a specified index.

Syntax:

remove element at index position from array
array.remove(position)

Example:

numbers = [1, 2, 3, 4, 5]
remove element at index 2 from numbers  // [1, 2, 4, 5]

fruits = ["apple", "banana", "orange"]
fruits.remove(1)  // ["apple", "orange"]

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Searching

is in - Check if Element Exists

Checks whether an element exists in an array.

Syntax:

if element is in array

Example:

fruits = ["apple", "banana", "orange"]

if "apple" is in fruits
    output "We have apples!"

if "grape" is in fruits
    output "We have grapes!"
else
    output "No grapes available"

---

Sorting

sort - Sort Array

Sorts an array in ascending or descending order.

Syntax:

sort array in ascending order
sort array in descending order
array.sort()
array.sort(descending)

Example:

numbers = [5, 2, 8, 1, 9]
sort numbers in ascending order  // [1, 2, 5, 8, 9]

numbers = [5, 2, 8, 1, 9]
sort numbers in descending order  // [9, 8, 5, 2, 1]

fruits = ["orange", "apple", "banana"]
fruits.sort()  // ["apple", "banana", "orange"]

---

Array Access

Index Access

Access elements using zero-based indexing.

Syntax:

element = array[index]

Example:

fruits = ["apple", "banana", "orange"]
firstFruit = fruits[0]   // "apple"
secondFruit = fruits[1]  // "banana"
thirdFruit = fruits[2]   // "orange"

---

Modify Element

Change the value of an element at a specific index.

Syntax:

array[index] = newValue

Example:

fruits = ["apple", "banana", "orange"]
fruits[1] = "grape"  // ["apple", "grape", "orange"]

---

Iteration

for each - Loop Through Array

Iterate over each element in an array.

Syntax:

for each element in array
    // code block

Example:

fruits = ["apple", "banana", "orange"]
for each fruit in fruits
    output fruit

---

Index-based Loop

Loop through array using indices.

Syntax:

for i from 0 to length of array - 1
    // use array[i]

Example:

numbers = [10, 20, 30, 40]
for i from 0 to length of numbers - 1
    output "Index {i}: {numbers[i]}"

---

Multi-dimensional Arrays

Create 2D Array

Example:

grid = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]

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Access 2D Array Element

Syntax:

value = array[row][column]

Example:

grid = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
value = grid[1][2]  // 6 (row 1, column 2)
value = grid[0][0]  // 1 (row 0, column 0)

---

Loop Through 2D Array

Example:

grid = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]

for each row in grid {
    for each value in row {
        output value
    }
}

---

Common Array Operations Example

// Create an empty shopping list
shoppingList = []

// Add items
append "milk" to shoppingList
append "bread" to shoppingList
append "eggs" to shoppingList

// Display list
output "Shopping List:"
for each item in shoppingList {
    output "- {item}"
}

// Check if we need to buy milk
if "milk" is in shoppingList
    output "Don't forget the milk!"

// Remove an item
remove element at index 1 from shoppingList  // removes "bread"

// Sort alphabetically
sort shoppingList in ascending order

// Display final list
output "Final list ({length of shoppingList} items):"
for i from 0 to length of shoppingList - 1 {
    output "{i + 1}. {shoppingList[i]}"
}