2019-11-05 02:09:40 -01:00
---
id: 5d792537b6cadae0f4b0cda1
2020-08-25 02:19:45 -07:00
title: Part 94
2019-11-05 02:09:40 -01:00
challengeType: 0
---
## Description
< section id = 'description' >
2019-12-09 19:37:02 +09:00
The `slice` method takes two arguments. It extracts characters from the string from the index specified by the first argument up to (but not including) the second argument. The index starts at 0.
2019-11-05 02:09:40 -01:00
Use the `slice` method to log the first two letters of `value` to the console.
< / section >
## Instructions
< section id = 'instructions' >
< / section >
## Tests
< section id = 'tests' >
```yml
tests:
- text: See description above for instructions.
testString: assert(code.replace(/\s/g, "").includes("console.log(value.slice(0,2))"));
```
< / section >
## Challenge Seed
< section id = 'challengeSeed' >
< div id = 'html-seed' >
```html
< 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 spreadsheetFunctions = {
"": x => x
};
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 => {
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 => document.getElementById(c + n).value;
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 => document.getElementById(match.toUpperCase()).value
);
const functionExpanded = applyFn(varExpanded);
return functionExpanded === x
? functionExpanded
: evalFormula(functionExpanded);
};
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] === "=") {}
};
< / script >
```
< / div >
### Before Test
< div id = 'html-setup' >
```html
<!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 >
```
< / div >
### After Test
< div id = 'html-teardown' >
```html
< / body >
< / html >
```
< / div >
< / section >
## Solution
< section id = 'solution' >
```html
< 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 spreadsheetFunctions = {
"": x => x
};
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 => {
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 => document.getElementById(c + n).value;
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 => document.getElementById(match.toUpperCase()).value
);
const functionExpanded = applyFn(varExpanded);
return functionExpanded === x
? functionExpanded
: evalFormula(functionExpanded);
};
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] === "=") {
console.log(value.slice(0, 2));
}
};
< / script >
```
< / section >
