Python 3 reference · 47 entries
Python String Methods
Every Python string method, from capitalize() to zfill(), with syntax, parameters and runnable examples. Strings are immutable, so every method returns a new string.
Call a method on any string with text.method(). Strings never change in place: methods such as replace()
and upper() return a new string, so assign the result (text = text.strip()).
| Name | Description | Since |
|---|---|---|
str.capitalize() |
Return a copy of the string with the first character in upper case and the rest in lower case. | 3.0 |
str.casefold() |
Return a case-folded copy for caseless comparison. Stronger than lower(): it also handles special cases like German ß. | 3.3 |
str.center() |
Return the string centred in a field of the given width, padded on both sides with a fill character (a space by default). | 3.0 |
str.count() |
Return the number of non-overlapping occurrences of a substring, optionally only between start and end positions. | 3.0 |
str.encode() |
Encode the string into bytes using a text encoding such as UTF-8 (the default), for files, networks and hashing. | 3.0 |
str.endswith() |
Return True if the string ends with the given suffix. Pass a tuple to check several suffixes at once. | 3.0 |
str.expandtabs() |
Return a copy where tab characters are replaced by spaces, aligning to tab stops every tabsize columns (8 by default). | 3.0 |
str.find() |
Return the lowest index where a substring is found, or -1 if it isn't. Optional start and end limit the search. | 3.0 |
str.format() |
Return a formatted string, filling {} placeholders with the arguments. f-strings are usually simpler. | 3.0 |
str.format_map() |
Like format(), but takes the values from a single mapping, which can be a dict or a dict subclass with defaults. | 3.2 |
str.index() |
Return the lowest index of a substring, like find(), but raise ValueError when it is not found. | 3.0 |
str.isalnum() |
Return True if every character is a letter or a digit and the string isn't empty. | 3.0 |
str.isalpha() |
Return True if every character is a letter (in any alphabet) and the string isn't empty. Spaces and digits return False. | 3.0 |
str.isascii() |
Return True if the string is empty or every character is ASCII (code points 0–127). | 3.7 |
str.isdecimal() |
Return True if every character is a decimal digit (0–9 and their equivalents in other scripts). The strictest digit check. | 3.0 |
str.isdigit() |
Return True if every character is a digit, including superscripts like ². Signs, spaces and decimal points return False. | 3.0 |
str.isidentifier() |
Return True if the string is a valid Python identifier: a name you could use for a variable, function or class. | 3.0 |
str.islower() |
Return True if all cased characters are lower case and there is at least one cased character. | 3.0 |
str.isnumeric() |
Return True if every character is numeric, including digits, fractions like ½ and numerals from other scripts. | 3.0 |
str.isprintable() |
Return True if every character is printable, or the string is empty. Newlines and tabs are not printable. | 3.0 |
str.isspace() |
Return True if every character is whitespace (spaces, tabs, newlines) and the string isn't empty. | 3.0 |
str.istitle() |
Return True if the string is title-cased: each word starts with an upper-case letter followed by lower-case letters. | 3.0 |
str.isupper() |
Return True if all cased characters are upper case and there is at least one cased character. | 3.0 |
str.join() |
Join the strings of an iterable into one string, with this string as the separator between them. | 3.0 |
str.ljust() |
Return the string left-justified in a field of the given width, padded on the right with a fill character. | 3.0 |
str.lower() |
Return a copy of the string with all cased characters converted to lower case. | 3.0 |
str.lstrip() |
Return a copy with leading characters removed: whitespace by default, or any of the characters you pass. | 3.0 |
str.maketrans() |
Create a translation table for translate(): map characters to replacements, or to None to delete them. | 3.0 |
str.partition() |
Split the string at the first occurrence of a separator into a 3-tuple: the part before, the separator, and the part after. | 3.0 |
str.removeprefix() |
Return the string without the given prefix if it starts with it; otherwise return it unchanged. | 3.9 |
str.removesuffix() |
Return the string without the given suffix if it ends with it; otherwise return it unchanged. | 3.9 |
str.replace() |
Return a copy with every occurrence of old replaced by new, or only the first count occurrences. | 3.0 |
str.rfind() |
Return the highest index where a substring is found, searching from the right, or -1 if it isn't found. | 3.0 |
str.rindex() |
Return the highest index of a substring, like rfind(), but raise ValueError when it is not found. | 3.0 |
str.rjust() |
Return the string right-justified in a field of the given width, padded on the left with a fill character. | 3.0 |
str.rpartition() |
Split the string at the last occurrence of a separator into a 3-tuple: before, separator and after. | 3.0 |
str.rsplit() |
Split the string into a list from the right. With maxsplit, only the last few splits are made. | 3.0 |
str.rstrip() |
Return a copy with trailing characters removed: whitespace by default, or any of the characters you pass. | 3.0 |
str.split() |
Split the string into a list of substrings at a separator. With no separator it splits on any whitespace. | 3.0 |
str.splitlines() |
Split the string into a list of lines at line boundaries (\n, \r\n and others), without the line endings. | 3.0 |
str.startswith() |
Return True if the string starts with the given prefix. Pass a tuple to check several prefixes at once. | 3.0 |
str.strip() |
Return a copy with leading and trailing characters removed: whitespace by default, or any of the characters you pass. | 3.0 |
str.swapcase() |
Return a copy with upper-case letters converted to lower case and vice versa. | 3.0 |
str.title() |
Return a title-cased copy: the first letter of each word upper case and the rest lower case. | 3.0 |
str.translate() |
Return a copy where each character is mapped through a translation table, replacing or deleting characters fast. | 3.0 |
str.upper() |
Return a copy of the string with all cased characters converted to upper case. | 3.0 |
str.zfill() |
Return the string padded on the left with zeros to the given width, keeping a leading + or - sign in front. | 3.0 |