Python provides powerful and flexible string manipulation capabilities. Strings in Python are sequences of characters enclosed in either single ('), double ("), or triple (''' """) quotes.
Creating Strings
Strings can be created in multiple ways:
string1 = 'Hello' string2 = "World" string3 = '''This is a multiline string''' print(string1) # Hello print(string2) # World print(string3) # This is # a multiline string
Special Characters: Escape Sequences
Python supports special characters using escape sequences:
text = "Hello\nWorld\tPython\\Programming" print(text) # Hello # World Python\Programming
String Indexing & Slicing
- Indexing: Accessing Characters
Python allows access to individual characters in a string using indexing:
word = "Python" print(word[0]) # P print(word[-1]) # n (last character)
- Slicing: Extracting Substrings
You can extract parts of a string using slicing:
word = "Programming" print(word[0:4]) # Prog print(word[:6]) # Progra (start from 0) print(word[3:]) # gramming (start from index 3 to end) print(word[-3:]) # ing (last 3 characters) print(word[::2]) # Pormig (every 2nd character)
String Concatenation & Repetition
Python allows concatenating (joining) strings using + and repeating strings using *:
str1 = "Hello" str2 = "World" print(str1 + " " + str2) # Hello World print(str1 * 3) # HelloHelloHello
Modifying Strings
- Uppercase, Lowercase, Title Case
text = "python programming" print(text.upper()) # PYTHON PROGRAMMING print(text.lower()) # python programming print(text.title()) # Python Programming
- Stripping Whitespace
text = " Hello World " print(text.strip()) # "Hello World" print(text.lstrip()) # "Hello World " print(text.rstrip()) # " Hello World"
s = "hello world"
print(s.capitalize()) # Hello world
s = "HeLLo WoRLd"
print(s.swapcase()) # hEllO wOrlD
s = "Python is great"
print(s.startswith("Python")) # True
s = "Python is great"
print(s.endswith("great")) # True
s = "hello world"
print(s.find("o")) # 4
Checking Substrings
text = "Python is awesome"
print("Python" in text) # True
print("Java" not in text) # True
- Finding & Counting
text = "Python programming is fun"
print(text.find("programming")) # 7 (index where it starts)
print(text.count("n")) # 3 (number of occurrences)
Replacing & Splitting Strings
- Replacing Substrings
text = "I love Java"
new_text = text.replace("Java", "Python")
print(new_text) # I love Python
- Splitting and Joining Strings
text = "apple,banana,grape"
words = text.split(",")
print(words) # ['apple', 'banana', 'grape']
joined = " - ".join(words)
print(joined) # apple - banana - grape
String Formatting
Python provides multiple ways to format strings.
- Old-style Formatting (%)
name = "Alice"
age = 25
print("Name: %s, Age: %d" % (name, age))
# Name: Alice, Age: 25
- format() Method
name = "Alice"
age = 25
print("Name: {}, Age: {}".format(name, age))
# Name: Alice, Age: 25
print("Name: {1}, Age: {0}".format(age, name))
# Name: Alice, Age: 25
- f-Strings (Python 3.6+)
f-Strings provide a more concise way to format strings:
name = "Alice"
age = 25
print(f"Name: {name}, Age: {age}")
# Name: Alice, Age: 25
- Using expressions inside f-Strings:
a = 5
b = 10
print(f"Sum: {a + b}") # Sum: 15
- Formatting Numbers:
pi = 3.14159
print(f"Pi: {pi:.2f}") # Pi: 3.14
Raw Strings (r prefix)
Raw strings ignore escape sequences:
path = r"C:\Users\Name\Documents" print(path) # C:\Users\Name\Documents
Multi-line Strings & Docstrings
text = """This is a
multi-line string"""
def greet():
"""This is a docstring.
It describes the function."""
return "Hello"
Checking String Properties
text = "Hello123"
print(text.isalpha()) # False (contains numbers)
print(text.isdigit()) # False (contains letters)
print(text.isalnum()) # True (letters + numbers)
print(text.isspace()) # False (not just spaces)
print("hello".islower()) # True
print("HELLO".isupper()) # True
print("Title Case".istitle()) # True
Length of String
s = "Python" print(len(s)) # 6
Reversing a String
text = "Python" print(text[::-1]) # nohtyP
Iterating Over a String
text = "Python"
for char in text:
print(char)
Converting Between Strings and Lists
# Convert string to list text = "Hello" char_list = list(text) print(char_list) # ['H', 'e', 'l', 'l', 'o'] # Convert list to string char_list = ['H', 'e', 'l', 'l', 'o'] text = "".join(char_list) print(text) # Hello
Python provides a rich set of string manipulation features, including indexing, slicing, formatting, escape sequences, and built-in methods. Using these efficiently can help you process and format text in various applications.