Why the 'replace' function of Python 3 is not working? I have been trying out this code: str.replace (str [I],str [I+1]) , where str is a string in python. After executing this
![replace Function in Python | Python String - replace ( ) method | replace a letter in python - YouTube replace Function in Python | Python String - replace ( ) method | replace a letter in python - YouTube](https://i.ytimg.com/vi/3M70DmbAh4A/hq720.jpg?sqp=-oaymwE7CK4FEIIDSFryq4qpAy0IARUAAAAAGAElAADIQj0AgKJD8AEB-AHmCIAC0AWKAgwIABABGGUgZShlMA8=&rs=AOn4CLDXjloofVOOAdgq3vlgO8Y6ajxZsw)
replace Function in Python | Python String - replace ( ) method | replace a letter in python - YouTube
![Python: Find the first appearance of the substring 'not' and 'poor' from a given string, if 'not' follows the 'poor', replace the whole 'not'...'poor' substring with 'good'. Return the resulting string - Python: Find the first appearance of the substring 'not' and 'poor' from a given string, if 'not' follows the 'poor', replace the whole 'not'...'poor' substring with 'good'. Return the resulting string -](https://www.w3resource.com/w3r_images/python-data-type-string-exercise-7.png)