This Python String Methods Cheat Sheet provides a comprehensive list of built-in string methods in Python, organized by category for easy reference. Each method includes a brief description and a simple example to illustrate its usage. Whether you're formatting, searching, modifying, or analyzing strings, this cheat sheet offers quick access to the tools you need. Ideal for both beginners and experienced programmers, it serves as a handy guide for efficient string manipulation in Python.
Case Conversion
str.capitalize()
Capitalizes the first character.
"hello world".capitalize()Output: "Hello world"
str.lower()
Converts all characters to lowercase.
"Hello World".lower()Output: "hello world"
str.upper()
Converts all characters to uppercase.
"Hello World".upper()Output: "HELLO WORLD"
str.title()
Converts the first character of each word to uppercase.
"hello world".title()Output: "Hello World"
str.swapcase()
Swaps the case of all characters.
"Hello World".swapcase()Output: "hELLO wORLD"
str.casefold()
Converts the string to casefolded (lowercase) version for case-insensitive comparisons.
"Hello World".casefold()Output: "hello world"
String Formatting
str.center(width, fillchar=' ')
Centers the string.
"hello".center(10, '-')Output: "--hello---"
str.ljust(width, fillchar=' ')
Left-justifies the string.
"hello".ljust(10, '-')Output: "hello-----"
str.rjust(width, fillchar=' ')
Right-justifies the string.
"hello".rjust(10, '-')Output: "-----hello"
str.zfill(width)
Pads the string with zeros on the left.
"42".zfill(5)Output: "00042"
str.format(*args, **kwargs)
Formats the string.
"Hello, {}!".format("world")Output: "Hello, world!"
str.format_map(mapping)
Formats the string using a dictionary.
data = {"name": "world"}
"Hello, {name}!".format_map(data)Output: "Hello, world!"
Search and Replace
str.find(sub, start=0, end=len(str))
Returns the lowest index of the substring.
"hello world".find("world")Output: 6
str.rfind(sub, start=0, end=len(str))
Returns the highest index of the substring.
"hello world world".rfind("world")Output: 12
str.index(sub, start=0, end=len(str))
Same as find() but raises ValueError when the substring is not found.
"hello world".index("world")Output: 6
str.rindex(sub, start=0, end=len(str))
Same as rfind() but raises ValueError when the substring is not found.
"hello world world".rindex("world")Output: 12
str.replace(old, new, count=-1)
Replaces occurrences of a substring with another substring.
"hello world".replace("world", "Python")Output: "hello Python"
Splitting and Joining
str.split(sep=None, maxsplit=-1)
Splits the string into a list.
"hello world".split()Output: ["hello", "world"]
str.rsplit(sep=None, maxsplit=-1)
Splits the string into a list, starting from the right.
"hello world".rsplit()Output: ["hello", "world"]
str.splitlines(keepends=False)
Splits the string at line breaks.
"hello\nworld".splitlines()Output: ["hello", "world"]
str.join(iterable)
Joins an iterable of strings.
"-".join(["hello", "world"])Output: "hello-world"
Trimming and Stripping
str.strip(chars=None)
Removes leading and trailing characters.
" hello ".strip()Output: "hello"
str.lstrip(chars=None)
Removes leading characters.
" hello ".lstrip()Output: "hello "
str.rstrip(chars=None)
Removes trailing characters.
" hello ".rstrip()Output: " hello"
Character Classification
str.isalnum()
Returns True if all characters are alphanumeric.
"hello123".isalnum()Output: True
str.isalpha()
Returns True if all characters are alphabetic.
"hello".isalpha()Output: True
str.isdigit()
Returns True if all characters are digits.
"12345".isdigit()Output: True
str.isnumeric()
Returns True if all characters are numeric.
"12345".isnumeric()Output: True
str.isdecimal()
Returns True if all characters are decimals.
"12345".isdecimal()Output: True
str.islower()
Returns True if all characters are lowercase.
"hello".islower()Output: True
str.isupper()
Returns True if all characters are uppercase.
"HELLO".isupper()Output: True
str.isspace()
Returns True if all characters are whitespace.
" ".isspace()Output: True
str.istitle()
Returns True if the string is in title case.
"Hello World".istitle()Output: True
Encoding and Decoding
str.encode(encoding='utf-8', errors='strict')
Encodes the string to bytes.
"hello".encode()Output: b'hello'
bytes.decode(encoding='utf-8', errors='strict')
Decodes bytes to a string.
b'hello'.decode()Output: "hello"
String Testing
str.startswith(prefix, start=0, end=len(str))
Returns True if the string starts with the specified prefix.
"hello world".startswith("hello")Output: True
str.endswith(suffix, start=0, end=len(str))
Returns True if the string ends with the specified suffix.
"hello world".endswith("world")Output: True
Other Utility Methods
str.count(sub, start=0, end=len(str))
Counts the occurrences of a substring.
"hello world".count("o")Output: 2
str.expandtabs(tabsize=8)
Expands tabs into spaces.
"hello\tworld".expandtabs(4)Output: "hello world"
str.partition(sep)
Splits the string into three parts around a separator.
"hello world".partition(" ")Output: ('hello', ' ', 'world')
str.rpartition(sep)
Splits the string into three parts, starting from the right.
"hello world world".rpartition(" ")Output: ('hello world', ' ', 'world')
str.maketrans(x, y=None, z=None)
Creates a translation table.
table = str.maketrans("abc", "123")str.translate(table)
Translates the string using a translation table.
table = str.maketrans("abc", "123")
"abc".translate(table)Output: "123"