Elixir:
Deleting characters matching a pattern

How to:

In Elixir, use the String.replace/4 function to delete characters matching a pattern. Check out these samples:

# Delete digits from a string
original_string = "Elixir2023Rocks!"
clean_string = String.replace(original_string, ~r/\d/, "")
IO.puts(clean_string) # Output: "ElixirRocks!"

# Remove punctuation
punctuationless_string = String.replace(original_string, ~r/[[:punct:]]/, "")
IO.puts(punctuationless_string) # Output: "Elixir2023Rocks"

# Strip out whitespace
no_whitespace_string = String.replace(original_string, ~r/\s/, "")
IO.puts(no_whitespace_string) # Output: "Elixir2023Rocks!"

Deep Dive

The use of pattern matching to delete characters in strings is not unique to Elixir; it’s a common feature in nearly all programming languages, evolved from regular expression (regex) capabilities in early Unix tools like sed and grep. Alternatives to String.replace/4 could be using pattern matching and recursion to manually traverse and modify a string, but this method is generally more verbose and complex, making built-in regex functions a go-to. Under the hood, String.replace/4 leverages Elixir’s Erlang heritage, utilizing the powerful pattern matching and string manipulation abilities of the BEAM virtual machine.

See Also:

• Elixir String module documentation: https://hexdocs.pm/elixir/String.html
• Regex in Elixir: https://hexdocs.pm/elixir/Regex.html
• ‘Learn Regular Expressions’: https://www.regular-expressions.info/tutorial.html
• Elixir School’s take on strings and pattern matching: https://elixirschool.com/en/lessons/basics/strings/