upper(),lower(),casefold(),find() in Python (2025)
1.upper()
Converts all characters of the string to uppercase.
Returns a new string with all uppercase letters.
2. lower()
Converts all characters of the string to lowercase.
Returns a new string with all lowercase letters
3. casefold()
Similar to lower(), but it is more aggressive. It is used for case-insensitive 4. 4.find()
If the substring is not found, it returns -1.
This method is case-sensitivecomparison