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