Letter frequency: Difference between revisions

Content added Content deleted
(→‎{{header|JavaScript}}: Added an ES6 variant, using the macOS 'Automation' lib for file access)
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=={{header|JavaScript}}==
=={{header|JavaScript}}==
===ES5===

JavaScript is no longer used only in environments which are carefully isolated from file systems, but JavaScript standards still do not specify standard file-system functions.
JavaScript is no longer used only in environments which are carefully isolated from file systems, but JavaScript standards still do not specify standard file-system functions.
Leaving aside the particular and variable details of how files will be opened and read in environments like Node.js and OS X JavaScript for Automation etc.,
Leaving aside the particular and variable details of how files will be opened and read in environments like Node.js and OS X JavaScript for Automation etc.,
Line 2,115: Line 2,115:
["i", 44], ["j", 1], ["k", 3], ["l", 34], ["m", 11], ["n", 41], ["o", 40], ["p", 8],
["i", 44], ["j", 1], ["k", 3], ["l", 34], ["m", 11], ["n", 41], ["o", 40], ["p", 8],
["q", 2], ["r", 35], ["s", 39], ["t", 55], ["u", 20], ["v", 7], ["w", 17], ["x", 2], ["y", 16]]</lang>
["q", 2], ["r", 35], ["s", 39], ["t", 55], ["u", 20], ["v", 7], ["w", 17], ["x", 2], ["y", 16]]</lang>

===ES6===

Using the 'JavaScript for Automation' embedding of a JSContext on macOS, for access to the file system:

<lang javascript>(() => {
'use strict';


// charCounts :: String -> [(Char, Int)]
const charCounts = s =>
sortBy(flip(comparing(snd)))(
Object.entries(
chars(s).reduce(
(a, c) => (
a[c] = 1 + (a[c] || 0),
a
), {}
)
)
);


// ----------------------- TEST -----------------------
// main :: IO ()
const main = () =>
either(msg => msg)(
compose(unlines, map(JSON.stringify), charCounts)
)(readFileLR('~/Code/charCount/miserables.txt'));


// -----------------GENERIC FUNCTIONS -----------------

// Left :: a -> Either a b
const Left = x => ({
type: 'Either',
Left: x
});


// Right :: b -> Either a b
const Right = x => ({
type: 'Either',
Right: x
});


// chars :: String -> [Char]
const chars = s =>
s.split('');


// comparing :: (a -> b) -> (a -> a -> Ordering)
const comparing = f =>
x => y => {
const
a = f(x),
b = f(y);
return a < b ? -1 : (a > b ? 1 : 0);
};

// compose (<<<) :: (b -> c) -> (a -> b) -> a -> c
const compose = (...fs) =>
fs.reduce(
(f, g) => x => f(g(x)),
x => x
);

// either :: (a -> c) -> (b -> c) -> Either a b -> c
const either = fl =>
fr => e => 'Either' === e.type ? (
undefined !== e.Left ? (
fl(e.Left)
) : fr(e.Right)
) : undefined;


// flip :: (a -> b -> c) -> b -> a -> c
const flip = f =>
1 < f.length ? (
(a, b) => f(b, a)
) : (x => y => f(y)(x));


// map :: (a -> b) -> [a] -> [b]
const map = f =>
// The list obtained by applying f
// to each element of xs.
// (The image of xs under f).
xs => (
Array.isArray(xs) ? (
xs
) : xs.split('')
).map(f);


// readFileLR :: FilePath -> Either String IO String
const readFileLR = fp => {
const
e = $(),
ns = $.NSString
.stringWithContentsOfFileEncodingError(
$(fp).stringByStandardizingPath,
$.NSUTF8StringEncoding,
e
);
return ns.isNil() ? (
Left(ObjC.unwrap(e.localizedDescription))
) : Right(ObjC.unwrap(ns));
};


// snd :: (a, b) -> b
const snd = tpl => tpl[1];


// sortBy :: (a -> a -> Ordering) -> [a] -> [a]
const sortBy = f =>
xs => xs.slice()
.sort((a, b) => f(a)(b));


// unlines :: [String] -> String
const unlines = xs =>
// A single string formed by the intercalation
// of a list of strings with the newline character.
xs.join('\n');

// MAIN ---
return main();
})();</lang>
{{Out}}
<pre>[" ",516452]
["e",325769]
["t",222955]
["a",199774]
["o",180987]
["h",170234]
["n",166901]
["i",165221]
["s",157643]
["r",145136]
["d",106989]
["l",97091]
["\n",73828]
["u",67370]
["c",62760]
["m",56011]
["f",53438]
["w",53332]
[",",48784]
["g",46086]
["p",39958]
["y",37945]
["b",34313]
[".",30487]
["v",24058]
["€",21159]
["â",21155]
["k",14110]
["T",12571]
["I",10067]
["A",7359]
["œ",7121]
["",7033]
["H",6605]
["M",6208]
[";",5885]
["E",4969]
["-",4775]
["C",4594]
["S",4404]
["x",3694]
["™",3633]
["!",3539]
["R",3535]
["P",3429]
["O",3401]
["j",3392]
["B",3193]
["W",3181]
["”",3071]
["N",3053]
["?",2976]
["F",2768]
["G",2512]
[":",2463]
["L",2452]
["J",2448]
["q",2398]
["Ã",2296]
["V",2210]
["_",2068]
["z",1847]
["D",1758]
["©",1328]
["Y",1238]
["U",900]
["1",732]
["8",412]
["X",333]
["K",323]
["˜",298]
["¨",294]
["3",254]
["2",242]
["0",212]
["5",208]
["*",179]
["(",172]
[")",172]
["4",170]
["‰",146]
["6",143]
["7",140]
["Q",135]
["[",122]
["]",122]
["9",118]
["¦",107]
["ª",74]
["Z",59]
["¢",56]
["§",48]
["®",39]
["Å",38]
["¼",37]
["\"",37]
["“",35]
["´",34]
["|",24]
["¯",18]
["¹",18]
["/",12]
["†",10]
["»",9]
["'",8]
["ˆ",5]
["«",5]
["+",5]
["’",3]
["±",2]
["‡",2]
["$",2]
["#",1]
["&",1]
["Â",1]
["½",1]
["{",1]
["}",1]
["%",1]
["@",1]</pre>


=={{header|jq}}==
=={{header|jq}}==
Retrieved from "https://rosettacode.org/wiki/Letter_frequency"