Converting a string to lower case

Haskell:
Converting a string to lower case

How to:

Haskell uses the Data.Char module to manipulate characters. The toLower function specifically changes a single character to lower case. You’ll map this function over a string to convert it entirely to lower case. Check out the code:

import Data.Char (toLower)

-- Convert a string to lower case
lowercaseString :: String -> String
lowercaseString = map toLower

-- Usage
main :: IO ()
main = putStrLn $ lowercaseString "Hello, Haskell!"

Sample output:

hello, haskell!

Deep Dive

Historically, the concept of letter cases comes from the era of manual typesetting when uppercase and lowercase letters were kept in separate cases. In programming, case conversion ensures uniformity, especially in case-insensitive operations.

Here’s the DL on Haskell particulars. The Data.Char module, housing toLower, debuted in the Haskell 98 standard. It’s been the go-to for character manipulations ever since. Other languages have their own methods, like .toLowerCase() in JavaScript or .lower() in Python, but in Haskell, map and toLower do the trick neatly.

Under the hood, toLower considers Unicode, meaning it can handle a vast repertoire of characters and scripts beyond the basic ASCII range – helpful for internationalization.

Alternatives? Sure, you could roll out your own function mimicking toLower, but why reinvent the wheel? Stick to Data.Char for readability and reliability. Plus, libraries like text and bytestring offer more performance-tuned approaches if you’re working with large datasets or aiming for performance.

Haskell:Converting a string to lower case

How to:

Deep Dive

See Also

Haskell:
Converting a string to lower case