Python’s built-in str class defines different methods. They help in manipulating strings. Since string is an immutable object, these methods return a copy of the original string, performing the respective processing on it. The string methods can be classified in following categories −
Case Conversion Methods
This category of built-in methods of Python’s str class deal with the conversion of alphabet characters in the string object. Following methods fall in this category −
| Sr.No. | Method & Description |
|---|---|
| 1 | capitalize()Capitalizes first letter of string |
| 2 | casefold()Converts all uppercase letters in string to lowercase. Similar to lower(), but works on UNICODE characters alos |
| 3 | lower()Converts all uppercase letters in string to lowercase. |
| 4 | swapcase()Inverts case for all letters in string. |
| 5 | title()Returns “titlecased” version of string, that is, all words begin with uppercase and the rest are lowercase. |
| 6 | upper()Converts lowercase letters in string to uppercase. |
Alignment Methods
Following methods in the str class control the alignment of characters within the string object.
| Sr.No. | Methods & Description |
|---|---|
| 1 | center(width, fillchar)Returns a string padded with fillchar with the original string centered to a total of width columns. |
| 2 | ljust(width[, fillchar])Returns a space-padded string with the original string left-justified to a total of width columns. |
| 3 | rjust(width,[, fillchar])Returns a space-padded string with the original string right-justified to a total of width columns. |
| 4 | expandtabs(tabsize = 8)Expands tabs in string to multiple spaces; defaults to 8 spaces per tab if tabsize not provided. |
| 5 | zfill (width)Returns original string leftpadded with zeros to a total of width characters; intended for numbers, zfill() retains any sign given (less one zero). |
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Split and Join Methods
Python has the following methods to perform split and join operations −
| Sr.No. | Method & Description |
|---|---|
| 1 | lstrip()Removes all leading whitespace in string. |
| 2 | rstrip()Removes all trailing whitespace of string. |
| 3 | strip()Performs both lstrip() and rstrip() on string |
| 4 | rsplit()Splits the string from the end and returns a list of substrings |
| 5 | split()Splits string according to delimiter (space if not provided) and returns list of substrings. |
| 6 | splitlines()Splits string at NEWLINEs and returns a list of each line with NEWLINEs removed. |
| 7 | partition()Splits the string in three string tuple at the first occurrence of separator |
| 8 | rpartition()Splits the string in three string tuple at the ladt occurrence of separator |
| 9 | join()Concatenates the string representations of elements in sequence into a string, with separator string. |
| 10 | removeprefix()Returns a string after removing the prefix string |
| 11 | removesuffix()Returns a string after removing the suffix string |
Boolean String Methods
Following methods in str class return True or False.
| Sr.No. | Methods & Description |
|---|---|
| 1 | isalnum()Returns true if string has at least 1 character and all characters are alphanumeric and false otherwise. |
| 2 | isalpha()Returns true if string has at least 1 character and all characters are alphabetic and false otherwise. |
| 3 | isdigit()Returns true if the string contains only digits and false otherwise. |
| 4 | islower()Returns true if string has at least 1 cased character and all cased characters are in lowercase and false otherwise. |
| 5 | isnumeric()Returns true if a unicode string contains only numeric characters and false otherwise. |
| 6 | isspace()Returns true if string contains only whitespace characters and false otherwise. |
| 7 | istitle()Returns true if string is properly “titlecased” and false otherwise. |
| 8 | isupper()Returns true if string has at least one cased character and all cased characters are in uppercase and false otherwise. |
| 9 | isascii()Returns True is all the characters in the string are from the ASCII character set |
| 10 | isdecimal()Checks if all the characters are decimal characters |
| 11 | isidentifier()Checks whether the string is a valid Python identifier |
| 12 | isprintable()Checks whether all the characters in the string are printable |
Find and Replace Methods
Following are the Find and Replace methods in Python −
| Sr.No. | Method & Description |
|---|---|
| 1 | count(sub, beg ,end)Counts how many times sub occurs in string or in a substring of string if starting index beg and ending index end are given. |
| 2 | find(sub, beg, end)Determine if sub occurs in string or in a substring of string if starting index beg and ending index end are given returns index if found and -1 otherwise. |
| 3 | index(sub, beg, end)Same as find(), but raises an exception if str not found. |
| 4 | replace(old, new [, max])Replaces all occurrences of old in string with new or at most max occurrences if max given. |
| 5 | rfind(sub, beg, end)Same as find(), but search backwards in string. |
| 6 | rindex( sub, beg, end)Same as index(), but search backwards in string. |
| 7 | startswith(sub, beg, end)Determines if string or a substring of string (if starting index beg and ending index end are given) starts with substring sub; returns true if so and false otherwise. |
| 8 | endswith(suffix, beg, end)Determines if string or a substring of string (if starting index beg and ending index end are given) ends with suffix; returns true if so and false otherwise. |
Translation Methods
Following are the Translation methods of the string −
| Sr.No. | Method & Description |
|---|---|
| 1 | maketrans()Returns a translation table to be used in translate function. |
| 2 | translate(table, deletechars=””)Translates string according to translation table str(256 chars), removing those in the del string. |
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