Python string methods

1. capitalize()

• Converts the first character of the string to uppercase.
• Example: 'hello'.capitalize() → 'Hello'

2. casefold()

• Converts the string to lowercase, more aggressive than lower().
• Example: 'HELLO'.casefold() → 'hello'

3. center(width, [fillchar])

• Centers the string within the specified width and fills the rest with the optional fill character.
• Example: 'hello'.center(10, '-') → '--hello---'

4. count(substring, [start, end])

• Counts occurrences of the substring within the string.
• Example: 'hello world'.count('o') → 2

5. encode(encoding, [errors])

• Encodes the string into the specified encoding.
• Example: 'hello'.encode('utf-8') → b'hello'

6. endswith(suffix, [start, end])

• Returns True if the string ends with the specified suffix.
• Example: 'hello'.endswith('lo') → True

7. expandtabs(tabsize)

• Expands tabs in a string to multiple spaces.
• Example: 'hello\tworld'.expandtabs(4) → 'hello world'

8. find(substring, [start, end])

• Returns the lowest index of the substring if found, else -1.
• Example: 'hello'.find('l') → 2

9. format(*args, **kwargs)

• Formats the string with the specified arguments.
• Example: 'Hello, {}'.format('world') → 'Hello, world'

10. format_map(mapping)

• Formats the string using a dictionary mapping.
• Example: '{name} is {age}'.format_map({'name': 'Alice', 'age': 30}) → 'Alice is 30'

11. index(substring, [start, end])

• Like find(), but raises ValueError if the substring is not found.
• Example: 'hello'.index('l') → 2

12. isalnum()

• Returns True if the string is alphanumeric (contains only letters and numbers).
• Example: 'hello123'.isalnum() → True

13. isalpha()

• Returns True if the string contains only letters.
• Example: 'hello'.isalpha() → True

14. isascii()

• Returns True if all characters in the string are ASCII.
• Example: 'hello'.isascii() → True

15. isdecimal()

• Returns True if the string contains only decimal characters.
• Example: '123'.isdecimal() → True

16. isdigit()

• Returns True if the string contains only digits.
• Example: '123'.isdigit() → True

17. isidentifier()

• Returns True if the string is a valid Python identifier.
• Example: 'hello'.isidentifier() → True

18. islower()

• Returns True if all characters in the string are lowercase.
• Example: 'hello'.islower() → True

19. isnumeric()

• Returns True if the string contains only numeric characters.
• Example: '123'.isnumeric() → True

20. isprintable()

• Returns True if all characters are printable.
• Example: 'hello\n'.isprintable() → False

21. isspace()

• Returns True if the string contains only whitespace.
• Example: ' '.isspace() → True

22. istitle()

• Returns True if the string follows title case.
• Example: 'Hello World'.istitle() → True

23. isupper()

• Returns True if all characters are uppercase.
• Example: 'HELLO'.isupper() → True

24. join(iterable)

• Joins elements of an iterable with the string as a separator.
• Example: '-'.join(['hello', 'world']) → 'hello-world'

25. ljust(width, [fillchar])

• Left-justifies the string within the given width and fills the rest with the optional fill character.
• Example: 'hello'.ljust(10, '-') → 'hello-----'

26. lower()

• Converts all characters to lowercase.
• Example: 'HELLO'.lower() → 'hello'

27. lstrip([chars])

• Removes leading whitespace (or specified characters).
• Example: ' hello'.lstrip() → 'hello'

28. maketrans(x[, y[, z]])

• Returns a translation table usable by translate().
• Example: str.maketrans('a', 'b')

29. partition(sep)

• Splits the string into three parts: before the separator, the separator, and after the separator.
• Example: 'hello world'.partition(' ') → ('hello', ' ', 'world')

30. replace(old, new[, count])

• Replaces occurrences of a substring with another.
• Example: 'hello'.replace('l', 'x') → 'hexxo'

31. rfind(substring, [start, end])

• Returns the highest index of the substring if found, else -1.
• Example: 'hello'.rfind('l') → 3

32. rindex(substring, [start, end])

• Like rfind(), but raises ValueError if the substring is not found.
• Example: 'hello'.rindex('l') → 3

33. rjust(width, [fillchar])

• Right-justifies the string and fills the rest with the optional fill character.
• Example: 'hello'.rjust(10, '-') → '-----hello'

34. rpartition(sep)

• Like partition(), but splits into three parts using the last occurrence of the separator.
• Example: 'hello world'.rpartition(' ') → ('hello', ' ', 'world')

35. rsplit([sep[, maxsplit]])

• Splits the string from the right by the separator.
• Example: 'a,b,c'.rsplit(',', 1) → ['a,b', 'c']

36. rstrip([chars])

• Removes trailing whitespace (or specified characters).
• Example: 'hello '.rstrip() → 'hello'

37. split([sep[, maxsplit]])

• Splits the string at each separator.
• Example: 'a,b,c'.split(',') → ['a', 'b', 'c']

38. splitlines([keepends])

• Splits the string at line breaks.
• Example: 'hello\nworld'.splitlines() → ['hello', 'world']

39. startswith(prefix, [start, end])

• Returns True if the string starts with the specified prefix.
• Example: 'hello'.startswith('he') → True

40. strip([chars])

• Removes leading and trailing whitespace (or specified characters).
• Example: ' hello '.strip() → 'hello'

41. swapcase()

• Swaps the case of all characters.
• Example: 'Hello'.swapcase() → 'hELLO'

42. title()

• Converts the first letter of each word to uppercase.
• Example: 'hello world'.title() → 'Hello World'

43. translate(table)

• Translates the string using a translation table.
• Example: 'abc'.translate(str.maketrans('a', 'b')) → 'bbc'

44. upper()

• Converts all characters to uppercase.
• Example: 'hello'.upper() → 'HELLO'

45. zfill(width)

• Pads the string with leading zeros until it reaches the specified width.
• Example: '42'.zfill(5) → '00042'