Commatizing numbers: Difference between revisions

</pre>

=={{header|Haskell}}==

{{Works with|GHC|7.8.3}}

<lang haskell>#!/usr/bin/env runhaskell

import Control.Monad

import Data.Char

import Data.List

import Data.Maybe

{-

I use the suffix "2" in identifiers in place of the more conventional

prime (single quote character), because Rosetta Code's syntax highlighter

still doesn't handle primes in identifiers correctly.

-}

isDigitOrPeriod :: Char -> Bool

isDigitOrPeriod '.' = True

isDigitOrPeriod c = isDigit c

chopUp :: Int -> String -> [String]

chopUp _ [] = []

chopUp by str

| by < 1 = [str] -- invalid argument, leave string unchanged

| otherwise = let (pfx, sfx) = splitAt by str

in pfx : chopUp by sfx

addSeps :: String -> Char -> Int -> (String -> String) -> String

addSeps str sep by rev =

let (leading, number) = span (== '0') str

number2 = rev $ intercalate [sep] $ chopUp by $ rev number

in leading ++ number2

processNumber :: String -> Char -> Int -> String

processNumber str sep by =

let (beforeDecimal, rest) = span isDigit str

(decimal, afterDecimal) = splitAt 1 rest

beforeDecimal2 = addSeps beforeDecimal sep by reverse

afterDecimal2 = addSeps afterDecimal sep by id

in beforeDecimal2 ++ decimal ++ afterDecimal2

commatize2 :: String -> Char -> Int -> String

commatize2 [] _ _ = []

commatize2 str sep by =

let (pfx, sfx) = span (not . isDigitOrPeriod) str

(number, sfx2) = span isDigitOrPeriod sfx

in pfx ++ processNumber number sep by ++ sfx2

commatize :: String -> Maybe Char -> Maybe Int -> String

commatize str sep by = commatize2 str (fromMaybe ',' sep) (fromMaybe 3 by)

input :: [(String, Maybe Char, Maybe Int)]

input =

[ ("pi=3.14159265358979323846264338327950288419716939937510582097494459231", Just ' ', Just 5)

, ("The author has two Z$100000000000000 Zimbabwe notes (100 trillion).", Just '.', Nothing)

, ("\"-in Aus$+1411.8millions\"", Nothing, Nothing)

, ("===US$0017440 millions=== (in 2000 dollars)", Nothing, Nothing)

, ("123.e8000 is pretty big.", Nothing, Nothing)

, ("The land area of the earth is 57268900(29% of the surface) square miles.", Nothing, Nothing)

, ("Ain't no numbers in this here words, nohow, no way, Jose.", Nothing, Nothing)

, ("James was never known as 0000000007", Nothing, Nothing)

, ("Arthur Eddington wrote: I believe there are 15747724136275002577605653961181555468044717914527116709366231425076185631031296 protons in the universe.", Nothing, Nothing)

, (" $-140000±100 millions.", Nothing, Nothing)

, ("6/9/1946 was a good year for some.", Nothing, Nothing)

]

main = do

forM_ input $ \(str, by, sep) -> do

putStrLn str

putStrLn $ commatize str by sep

putStrLn ""

</lang>

{{out}}

<pre>

pi=3.14159265358979323846264338327950288419716939937510582097494459231

pi=3.14159 26535 89793 23846 26433 83279 50288 41971 69399 37510 58209 74944 59231

The author has two Z$100000000000000 Zimbabwe notes (100 trillion).

The author has two Z$100.000.000.000.000 Zimbabwe notes (100 trillion).

"-in Aus$+1411.8millions"

"-in Aus$+1,411.8millions"

===US$0017440 millions=== (in 2000 dollars)

===US$0017,440 millions=== (in 2000 dollars)

123.e8000 is pretty big.

123.e8000 is pretty big.

The land area of the earth is 57268900(29% of the surface) square miles.

The land area of the earth is 57,268,900(29% of the surface) square miles.

Ain't no numbers in this here words, nohow, no way, Jose.

Ain't no numbers in this here words, nohow, no way, Jose.

James was never known as 0000000007

James was never known as 0000000007

Arthur Eddington wrote: I believe there are 15747724136275002577605653961181555468044717914527116709366231425076185631031296 protons in the universe.

Arthur Eddington wrote: I believe there are 15,747,724,136,275,002,577,605,653,961,181,555,468,044,717,914,527,116,709,366,231,425,076,185,631,031,296 protons in the universe.

$-140000±100 millions.

$-140,000±100 millions.

6/9/1946 was a good year for some.

6/9/1946 was a good year for some.