Python - String Methods
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). |
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. |
