Haskell - Printing Multiple Non-String Variables

Question

I am writing a program that reads two integers from the command line, doubles them, and then prints them back out. So my program reads in the Args, casts them to Ints, and then doubles them. My question is about outputting: in Python, I could just write:

>>>a = 9
>>>b = 10
>>>print a,b
9 10

which gives me satisfactory output. In Haskell, there is a similar print statement to print a given variable - e.g.

Prelude> let a = 10
Prelude> print a
10

I am wondering if there is a Haskell equivalent to python print a,b, so I can print multiple variables at once. Otherwise, I've had to do is convert the doubled Ints back to strings, and then write:
putStrLn (doubledint1 ++ " " ++ doubledint2)

Is there a way to print multiple variables that is more effective than the laborious method of manually converting to strings, and then calling putStrLn on their concatenation?

Answer 1

You can use mapM_, either over print or putStr.show:

Prelude> mapM_ print [a, b]
9
10

mapM_ (putStr . show) [a, b]
910Prelude>

See input-output section of learn you a haskell.

You could get the spaces and new line:

Prelude> let pylike_print ints = mapM_ (\x -> putStr $ (show x) ++ " ") ints >> putStr "\n"
Prelude> pylike_print [9, 10]
9 10