freeCodeCamp/part-016.md at e8b6a9e5dd2a43f1c392656acdf257bff77ff098

chore(learn): Remove remaining isHidden keys from frontmatter (English and Chinese challenges) (#39809 )

* fix: remove isHidden key from tool template

* fix: removed isHidden key from English challenges

* fix: remove isHidden key from Chinese challenges

2020-10-08 14:18:47 +02:00

2.0 KiB

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id, title, challengeType

id	title	challengeType
5d792533bb38fab70b27f527	Part 16	0

Description

arg1 and arg2 are the numbers input by the user in a string such as "1+3".

Pass parseFloat(arg1) and parseFloat(arg2) as the arguments to infixToFunction[fn] (remember infixToFunction[fn] is a function).

Instructions

Tests

tests:
  - text: See description above for instructions.
    testString: const regex = /([0-9.]+)([+-\/*])([0-9.]+)/; assert(infixEval("23+35", regex) === "58" && infixEval("100-20", regex) === "80" && infixEval("10*10", regex) === "100" && infixEval("120/6", regex) === "20");

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, (match, arg1, fn, arg2) =>
    infixToFunction[fn]
  );


</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, (match, arg1, fn, arg2) =>
    infixToFunction[fn](parseFloat(arg1), parseFloat(arg2))
  );
</script>

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