Python String

1. Creating Strings

single_quote = 'Hello'
double_quote = "World"
multi_line = """This is
a multi-line
string"""

print(single_quote)
print(double_quote)
print(multi_line)

Strings can be defined using single, double, or triple quotes.

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2. Accessing String Characters (Indexing)

text = "Python"

print(text[0])    # P
print(text[-1])   # n

Strings support positive and negative indexing.

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3. String Slicing

word = "Programming"

print(word[0:6])   # Output: Progra
print(word[:4])    # Output: Prog
print(word[4:])    # Output: ramming

Extracts substrings without modifying the original string.

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4. String Immutability

name = "Python"

# name[0] = "J"  # Raises TypeError
print(name)

Strings cannot be changed once created.

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5. String Concatenation and Repetition

first = "Hello"
second = "World"

print(first + " " + second)  # Hello World
print(first * 3)             # HelloHelloHello

Used to combine or duplicate strings.

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6. String Length and Membership

message = "Data Science"

print(len(message))         # Output: 12
print("Data" in message)    # True
print("AI" not in message)  # True

Performs validation and search checks.

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7. Common String Methods

text = "  python programming  "

print(text.upper())     # PYTHON PROGRAMMING
print(text.lower())     # python programming
print(text.strip())     # python programming
print(text.replace("python", "Java"))  # Java programming

Used for formatting and transformation.

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8. Splitting and Joining Strings

sentence = "Python is powerful"

words = sentence.split(" ")
print(words)  # ['Python', 'is', 'powerful']

joined = "-".join(words)
print(joined)  # Python-is-powerful

Essential for text processing and parsing.

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9. String Formatting

name = "Alice"
score = 95

print(f"{name} scored {score} marks.")                # f-string
print("{} scored {} marks.".format(name, score))      # format method

Dynamic and readable string construction techniques.

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10. Iterating Through a String

word = "Code"

for char in word:
    print(char)

Strings are iterable character by character.

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