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 β
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 β
| Sr.No. | Method & Description |
|---|---|
1 |
Capitalizes first letter of string |
2 |
Converts all uppercase letters in string to lowercase. Similar to lower(), but works on UNICODE characters alos |
3 |
Converts all uppercase letters in string to lowercase. |
4 |
Inverts case for all letters in string. |
5 |
Returns "titlecased" version of string, that is, all words begin with uppercase and the rest are lowercase. |
6 |
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 |
Returns a string padded with fillchar with the original string centered to a total of width columns. |
2 |
Returns a space-padded string with the original string left-justified to a total of width columns. |
3 |
Returns a space-padded string with the original string right-justified to a total of width columns. |
4 |
Expands tabs in string to multiple spaces; defaults to 8 spaces per tab if tabsize not provided. |
5 |
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 β
| Sr.No. | Method & Description |
|---|---|
1 |
Removes all leading whitespace in string. |
2 |
Removes all trailing whitespace of string. |
3 |
Performs both lstrip() and rstrip() on string |
4 |
Splits the string from the end and returns a list of substrings |
5 |
Splits string according to delimiter (space if not provided) and returns list of substrings. |
6 |
Splits string at NEWLINEs and returns a list of each line with NEWLINEs removed. |
7 |
Splits the string in three string tuple at the first occurrence of separator |
8 |
Splits the string in three string tuple at the ladt occurrence of separator |
9 |
Concatenates the string representations of elements in sequence into a string, with separator string. |
10 |
Returns a string after removing the prefix string |
11 |
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 |
Returns true if string has at least 1 character and all characters are alphanumeric and false otherwise. |
2 |
Returns true if string has at least 1 character and all characters are alphabetic and false otherwise. |
3 |
Returns true if the string contains only digits and false otherwise. |
4 |
Returns true if string has at least 1 cased character and all cased characters are in lowercase and false otherwise. |
5 |
Returns true if a unicode string contains only numeric characters and false otherwise. |
6 |
Returns true if string contains only whitespace characters and false otherwise. |
7 |
Returns true if string is properly "titlecased" and false otherwise. |
8 |
Returns true if string has at least one cased character and all cased characters are in uppercase and false otherwise. |
9 |
Returns True is all the characters in the string are from the ASCII character set |
10 |
Checks if all the characters are decimal characters |
11 |
Checks whether the string is a valid Python identifier |
12 |
Checks whether all the characters in the string are printable |
Find and Replace Methods
Following are the Find and Replace methods in Python β
| Sr.No. | Method & Description |
|---|---|
1 |
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 |
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 |
Same as find(), but raises an exception if str not found. |
4 |
Replaces all occurrences of old in string with new or at most max occurrences if max given. |
5 |
Same as find(), but search backwards in string. |
6 |
Same as index(), but search backwards in string. |
7 |
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 |
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 β
| Sr.No. | Method & Description |
|---|---|
1 |
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. |