How to concatenate two integers in Haskell

Haskell is a statically typed, functional, and concurrent programming language with a dynamic range of packages.

We might come across situations entailing the concatenation of two integer values. In this scenario, we can use the following methods:

  • Concatenating integers as strings

  • Concatenating integers as integers

To concatenate two integer values in Haskell, the easiest way will be to convert both values to a string and then concatenate them using the Haskell concatenation operators.

This process involves:

  • The method show used to convert an int value to string.
    The syntax of this method is: show n, where n represents the integer value to be converted.

  • The operator (<> or ++) used for concatenating the converted string values, as follows: result = s1 <> s2 or result = s1 ++ s2

Let's go through the following examples for a better understanding of these methods:

Concatenating integers as strings

This example illustrates how to concatenate two integer values and return a string output:

concatTwoIntToStr :: Int -> Int -> String
concatTwoIntToStr n1 n2 = ((show n1) ++ (show n2))
main :: IO ()
main = do
   let a = 42
       b = 45
   putStr "The result is: "
   let result = concatTwoIntToStr a b
   putStr (result)

Let's go over the code widget above:

  • Lines 1–2: Define a function that accepts two integer parameters, convert them to a string using the show method, then concatenate them and return back the concatenated value.

  • Lines 6–7: Declare two integer values.

  • Line 9: Invoke the function concatTwoIntToStr previously defined and store the result in a variable named result.

  • Line 10: Print out the string result.

Concatenating integers as integers

This example illustrates how to concatenate two integer values and return an integer value as output:

concatTwoIntToInt :: Int -> Int -> Int
concatTwoIntToInt n1 n2 = read ((show n1) ++ (show n2))
main :: IO ()
main = do
   let a = 42
       b = 45
   putStr "The result is: "
   let result = concatTwoIntToInt a b
   putStr (show result)

Let's go over the code widget above:

  • Lines 1–2: Define a function that accepts two integer parameters, convert them to a string using the show method, then concatenate them and return back the concatenated value. The read function is applied to convert the result from a string to a number.

  • Lines 6–7: Declare two integer values.

  • Line 9: Invoke the function concatTwoIntToInt previously defined and store the result in a variable named result.

  • Line 10: Print out the result while using the show method to convert the integer result to a string.

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