How to Sort Array in Ruby: Simple Syntax and Examples

In Ruby, you can sort an array using the sort method, which returns a new sorted array. To sort the original array in place, use sort!. Both methods work on arrays of numbers, strings, or any objects that can be compared.

Syntax

The basic syntax to sort an array is using array.sort, which returns a new sorted array without changing the original. To sort the array itself, use array.sort!. You can also provide a block to customize sorting order.

• array.sort: returns a new sorted array.
• array.sort!: sorts the array in place.
• array.sort { |a, b| ... }: custom sorting logic.

ruby

array = [3, 1, 4, 2]
sorted_array = array.sort
array.sort! # sorts in place

Example

This example shows how to sort an array of numbers and an array of strings. It also demonstrates sorting in ascending and descending order.

ruby

numbers = [5, 2, 9, 1]
strings = ["banana", "apple", "cherry"]

# Sort numbers ascending
sorted_numbers = numbers.sort
puts sorted_numbers.inspect

# Sort strings ascending
sorted_strings = strings.sort
puts sorted_strings.inspect

# Sort numbers descending using block
descending_numbers = numbers.sort { |a, b| b <=> a }
puts descending_numbers.inspect

Output

[1, 2, 5, 9]
["apple", "banana", "cherry"]
[9, 5, 2, 1]

Common Pitfalls

One common mistake is expecting sort to change the original array, but it returns a new sorted array instead. Use sort! to sort in place. Another pitfall is forgetting that sorting strings is case-sensitive by default, which can lead to unexpected order.

ruby

arr = ["b", "A", "c"]

# Wrong: expecting original array to change
arr.sort
puts arr.inspect  # Output: ["b", "A", "c"] (unchanged)

# Right: sort in place
arr.sort!
puts arr.inspect  # Output: ["A", "b", "c"]

# Case-insensitive sort
arr = ["b", "A", "c"]
sorted_case_insensitive = arr.sort { |a, b| a.downcase <=> b.downcase }
puts sorted_case_insensitive.inspect  # Output: ["A", "b", "c"]

Output

["b", "A", "c"]
["A", "b", "c"]
["A", "b", "c"]

Quick Reference

Here is a quick summary of Ruby array sorting methods:

Method	Description
array.sort	Returns a new sorted array, original unchanged.
array.sort!	Sorts the array in place, modifying the original.
array.sort { |a, b| ... }	Sorts with custom comparison logic.
array.sort_by { |item| ... }	Sorts by computed values for each item.

Key Takeaways

Use sort to get a new sorted array without changing the original.

Use sort! to sort the array itself and modify it.

Provide a block to sort for custom sorting rules.

Sorting strings is case-sensitive by default; use downcase for case-insensitive sorting.

Remember sort returns a new array, so assign it if you want to keep the sorted result.