Reveal the Number

Reveal the Number


You are given a string of different characters (letters, digits and other symbols). The goal is to "extract" the number from the string: concatenate only digits, number sign and "." (if present) and return the result in number format. If no number can be extracted (no digits in the given string) - return null.

Expected behavior:

  • take into consideration the LAST number sign before the FIRST digit;
  • take into consideration the FIRST dot in the string (It's guaranteed, that it goes after at least one digit or has at least one digit after). If there is a dot, return as float, otherwise - integer.

Input: String (string).

Output: Number or null.


assert.strictEqual(revealNum("F0(t}"), 0);
assert.strictEqual(revealNum("Utc&g"), null);
assert.strictEqual(revealNum("-aB%|_-+2ADS.12+3.ADS1.2"), 2.12312);
assert.strictEqual(revealNum("-aB%|_+-2ADS.12+3.ADS1.2"), -2.12312);
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CheckiO Extensions

CheckiO Extensions allow you to use local files to solve missions. More info in a blog post.

In order to install CheckiO client you'll need installed Python (version at least 3.8)

Install CheckiO Client first:

pip3 install checkio_client

Configure your tool

checkio --domain=js config --key=

Sync solutions into your local folder

checkio sync

(in beta testing) Launch local server so your browser can use it and sync solution between local file end extension on the fly. (doesn't work for safari)

checkio serv -d

Alternatevly, you can install Chrome extension or FF addon

checkio install-plugin
checkio install-plugin --ff
checkio install-plugin --chromium

Read more here about other functionality that the checkio client provides. Feel free to submit an issue in case of any difficulties.

Pair Programming (Beta-version)

Welcome to Pair Programming! Engage in real-time collaboration on coding projects by starting a session and sharing the provided unique URL with friends or colleagues. This feature is perfect for joint project development, debugging, or learning new skills together. Simply click 'Start Session' to begin your collaborative coding journey!

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