Replace All Occurrences

Replace All Occurrences


This function should take three strings as input: the main text, the target substring, and the replacement substring. It should return a new string where all occurrences of the target substring within the main text are replaced with the replacement substring.


Input: Three strings (str).

Output: String (str).


assert replace_all("hello world", "world", "TypeScript") == "hello TypeScript"
assert (
    replace_all("hello world world", "world", "TypeScript")
    == "hello TypeScript TypeScript"
assert replace_all("TypeScript is fun", "fun", "awesome") == "TypeScript is awesome"
assert replace_all("aaa", "a", "b") == "bbb"

How it’s used:

  • in text editors for find-and-replace functionality;
  • in data transformation tools to standardize or clean data;
  • in website template systems to replace placeholders with actual content.


  • all inputs should be strings: mainText, target, replacement ∈ string;
  • the target should not be an empty string: length(target) > 0.

Invalid hot key. Each hot key should be unique and valid
Hot keys:
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=py 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.

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