String Manipulation

# Single or double quotes
name = "Alice"
name = 'Alice'  # Same thing

# Multi-line strings
message = """This is a
multi-line
string"""

# Escape characters
quote = "She said \"Hello\""  # She said "Hello"
newline = "Line 1\nLine 2"  # Two lines

# Using + operator
first = "Hello"
last = "World"
greeting = first + " " + last  # "Hello World"

# Using f-strings (recommended)
name = "Alice"
age = 25
message = f"My name is {name} and I'm {age} years old"

text = "  Hello World  "

# Case conversion
print(text.upper())      # "  HELLO WORLD  "
print(text.lower())      # "  hello world  "
print(text.title())      # "  Hello World  "
print(text.capitalize()) # "  hello world  "

# Stripping whitespace
print(text.strip())      # "Hello World" (removes spaces)
print(text.lstrip())     # "Hello World  " (left only)
print(text.rstrip())     # "  Hello World" (right only)

# Finding and replacing
text = "Hello World"
print(text.find("World"))        # 6 (index where found)
print(text.replace("World", "Python"))  # "Hello Python"

# Checking content
print(text.startswith("Hello"))  # True
print(text.endswith("World"))    # True
print("Hello" in text)           # True

text = "Python"

# Access characters by index
print(text[0])    # P (first character)
print(text[-1])   # n (last character)

# Slicing
print(text[0:3])  # Pyt (characters 0, 1, 2)
print(text[:3])   # Pyt (from start to index 3)
print(text[3:])   # hon (from index 3 to end)
print(text[::-1]) # nohtyP (reverse)

name = "Alice"
age = 25

# f-strings (Python 3.6+, recommended)
message = f"Name: {name}, Age: {age}"

# .format() method
message = "Name: {}, Age: {}".format(name, age)
message = "Name: {0}, Age: {1}".format(name, age)

# % formatting (older style)
message = "Name: %s, Age: %d" % (name, age)

text = "Hello World"

# Get length
print(len(text))  # 11

# Count occurrences
print(text.count("l"))  # 3

# Split into list
words = text.split()  # ["Hello", "World"]
words = text.split("l")  # ["He", "o Wor", "d"]

# Join list into string
words = ["Hello", "World"]
text = " ".join(words)  # "Hello World"

# Check if string is numeric
text = "123"
print(text.isdigit())  # True

# Check if alphabetic
text = "Hello"
print(text.isalpha())  # True

# Check if alphanumeric
text = "Hello123"
print(text.isalnum())  # True