2fbafda167
* Add meta.json for spreadsheet * Add spreadsheet files * Close code tags for tests in 2 files * Add solution section * Add index file * Add javascript-spreadsheet to stringifier * Move index to step * Rename steps in meta.json * Rename step numbers in files * Add index file to proper location * Remove inappropriate files from spreadsheet dir * Fix typo in first step * Fix test sections * Rename files to correct step * Fix broken tests * Add newline between sections * Change challengeType from 1 to 0 * Add missng ) in step-079.md * test -> tests in step-079 * Simplify test in step-103 * Fix step-137 test * Remove last step * Added solutions and adjusted some tests * Fix some challenges * Remove wrong spaces * Fix more tests * Add missing semicolon * Fix more tests * Fix type: lastttwo * Fix all remaining tests
7.6 KiB
7.6 KiB
id, title, challengeType, isBeta
| id | title | challengeType | isBeta |
|---|---|---|---|
| 5d79253949802f8587c8bbd3 | Step 118 | 0 | true |
Description
The filter method keeps only the elements of an array that satisfy the function passed to it:
[1, 10, 8, 3, 4, 5].filter(x > 3); // [10, 8, 4, 5]
Use filter to add a function called even to spreadsheetFunctions, which returns all the even elements of an array, nums.
Instructions
Tests
tests:
- text: See description above for instructions.
testString: assert(JSON.stringify(spreadsheetFunctions.even([2,3,5,6,9,4])) === "[2,6,4]" && code.includes("filter"));
Challenge Seed
<script>
const infixToFunction = {
"+": (x, y) => x + y,
"-": (x, y) => x - y,
"*": (x, y) => x * y,
"/": (x, y) => x / y
};
const infixEval = (str, regex) =>
str.replace(regex, (_, arg1, fn, arg2) =>
infixToFunction[fn](parseFloat(arg1), parseFloat(arg2))
);
const highPrecedence = str => {
const regex = /([0-9.]+)([*\/])([0-9.]+)/;
const str2 = infixEval(str, regex);
return str === str2 ? str : highPrecedence(str2);
};
const isEven = num => num % 2 === 0;
const spreadsheetFunctions = {
"": x => x,
random: ([x, y]) => Math.floor(Math.random() * y + x),
increment: nums => nums.map(x => x + 1),
firsttwo: arr => arr.slice(0, 2),
lasttwo: arr => arr.slice(-2)
};
const applyFn = str => {
const noHigh = highPrecedence(str);
const infix = /([0-9.]+)([+-])([0-9.]+)/;
const str2 = infixEval(noHigh, infix);
const regex = /([a-z]*)\(([0-9., ]*)\)(?!.*\()/i;
const toNumberList = args => args.split(",").map(parseFloat);
const applyFunction = (fn, args) =>
spreadsheetFunctions[fn.toLowerCase()](toNumberList(args));
return str2.replace(
regex,
(match, fn, args) =>
spreadsheetFunctions.hasOwnProperty(fn.toLowerCase()) ? applyFunction(fn, args) : match
);
};
const range = (start, end) =>
start > end ? [] : [start].concat(range(start + 1, end));
const charRange = (start, end) =>
range(start.charCodeAt(0), end.charCodeAt(0)).map(x =>
String.fromCharCode(x)
);
const evalFormula = (x, cells) => {
const idToText = id => cells.find(cell => cell.id === id).value;
const rangeRegex = /([A-J])([1-9][0-9]?):([A-J])([1-9][0-9]?)/gi;
const rangeFromString = (n1, n2) => range(parseInt(n1), parseInt(n2));
const elemValue = n => c => idToText(c + n);
const addChars = c1 => c2 => n => charRange(c1, c2).map(elemValue(n));
const varRangeExpanded = x.replace(rangeRegex, (_, c1, n1, c2, n2) =>
rangeFromString(n1, n2).map(addChars(c1)(c2))
);
const varRegex = /[A-J][1-9][0-9]?/gi;
const varExpanded = varRangeExpanded.replace(
varRegex,
match => idToText(match.toUpperCase())
);
const functionExpanded = applyFn(varExpanded);
return functionExpanded === x
? functionExpanded
: evalFormula(functionExpanded, cells);
};
window.onload = () => {
const container = document.getElementById("container");
const createLabel = name => {
const label = document.createElement("div");
label.className = "label";
label.textContent = name;
container.appendChild(label);
};
const letters = charRange("A", "J");
letters.forEach(createLabel);
range(1, 99).forEach(x => {
createLabel(x);
letters.forEach(y => {
const input = document.createElement("input");
input.type = "text";
input.id = y + x;
input.onchange = update;
container.appendChild(input);
});
});
};
const update = event => {
const element = event.target;
const value = element.value.replace(/\s/g, "");
if (!value.includes(element.id) && value[0] === "=") {
element.value = evalFormula(
value.slice(1),
Array.from(document.getElementById("container").children)
);
}
};
</script>
Before Test
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Spreadsheet</title>
<style>
#container {
display: grid;
grid-template-columns: 50px repeat(10, 200px);
grid-template-rows: repeat(11, 30px);
}
.label {
background-color: lightgray;
text-align: center;
vertical-align: middle;
line-height: 30px;
}
</style>
</head>
<body>
<div id="container">
<div></div>
</div>
After Test
</body>
</html>
Solution
<script>
const infixToFunction = {
"+": (x, y) => x + y,
"-": (x, y) => x - y,
"*": (x, y) => x * y,
"/": (x, y) => x / y
};
const infixEval = (str, regex) =>
str.replace(regex, (_, arg1, fn, arg2) =>
infixToFunction[fn](parseFloat(arg1), parseFloat(arg2))
);
const highPrecedence = str => {
const regex = /([0-9.]+)([*\/])([0-9.]+)/;
const str2 = infixEval(str, regex);
return str === str2 ? str : highPrecedence(str2);
};
const isEven = num => num % 2 === 0;
const spreadsheetFunctions = {
"": x => x,
random: ([x, y]) => Math.floor(Math.random() * y + x),
increment: nums => nums.map(x => x + 1),
firsttwo: arr => arr.slice(0, 2),
lasttwo: arr => arr.slice(-2),
even: nums => nums.filter(isEven)
};
const applyFn = str => {
const noHigh = highPrecedence(str);
const infix = /([0-9.]+)([+-])([0-9.]+)/;
const str2 = infixEval(noHigh, infix);
const regex = /([a-z]*)\(([0-9., ]*)\)(?!.*\()/i;
const toNumberList = args => args.split(",").map(parseFloat);
const applyFunction = (fn, args) =>
spreadsheetFunctions[fn.toLowerCase()](toNumberList(args));
return str2.replace(
regex,
(match, fn, args) =>
spreadsheetFunctions.hasOwnProperty(fn.toLowerCase()) ? applyFunction(fn, args) : match
);
};
const range = (start, end) =>
start > end ? [] : [start].concat(range(start + 1, end));
const charRange = (start, end) =>
range(start.charCodeAt(0), end.charCodeAt(0)).map(x =>
String.fromCharCode(x)
);
const evalFormula = (x, cells) => {
const idToText = id => cells.find(cell => cell.id === id).value;
const rangeRegex = /([A-J])([1-9][0-9]?):([A-J])([1-9][0-9]?)/gi;
const rangeFromString = (n1, n2) => range(parseInt(n1), parseInt(n2));
const elemValue = n => c => idToText(c + n);
const addChars = c1 => c2 => n => charRange(c1, c2).map(elemValue(n));
const varRangeExpanded = x.replace(rangeRegex, (_, c1, n1, c2, n2) =>
rangeFromString(n1, n2).map(addChars(c1)(c2))
);
const varRegex = /[A-J][1-9][0-9]?/gi;
const varExpanded = varRangeExpanded.replace(
varRegex,
match => idToText(match.toUpperCase())
);
const functionExpanded = applyFn(varExpanded);
return functionExpanded === x
? functionExpanded
: evalFormula(functionExpanded, cells);
};
window.onload = () => {
const container = document.getElementById("container");
const createLabel = name => {
const label = document.createElement("div");
label.className = "label";
label.textContent = name;
container.appendChild(label);
};
const letters = charRange("A", "J");
letters.forEach(createLabel);
range(1, 99).forEach(x => {
createLabel(x);
letters.forEach(y => {
const input = document.createElement("input");
input.type = "text";
input.id = y + x;
input.onchange = update;
container.appendChild(input);
});
});
};
const update = event => {
const element = event.target;
const value = element.value.replace(/\s/g, "");
if (!value.includes(element.id) && value[0] === "=") {
element.value = evalFormula(
value.slice(1),
Array.from(document.getElementById("container").children)
);
}
};
</script>