Strings

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Strings are a fundamental data type in most programming languages. They are sequences of characters, and they can include letters, numbers, symbols, and whitespace. Here’s a brief overview:

Definition:

• Strings: Ordered collections of characters, typically used to represent words, sentences, or any text.

Characteristics:

1. Immutable: In many languages like Python and Java, strings are immutable, meaning once a string is created, it cannot be modified. Instead, any operations that “modify” a string actually return a new string.
2. Indexable: Characters within a string can be accessed using an index.
3. Iterable: Strings can be looped over, one character at a time.

Common Operations:

1. Concatenation: Combining two or more strings.

   greeting = "Hello" + " " + "World"  # "Hello World"

2. Substring: Extracting a portion of a string.

   text = "Hello World"
   sub = text[0:5]  # "Hello"

3. Length: Finding the number of characters in a string.

   len("Hello")  # 5

4. Search: Finding the position of a substring within a string.

   "Hello World".index("World")  # 6

5. Replacement: Replacing a part of a string with another string.

   "Hello World".replace("World", "Universe")  # "Hello Universe"

6. Case Conversion: Changing the case of a string.

   "hello".upper()  # "HELLO"
   "HELLO".lower()  # "hello"

Escape Sequences:

In strings, certain characters are represented using escape sequences because they have special meanings. The most common escape sequences include:

• \n: Newline
• \t: Tab
• \": Double Quote
• \': Single Quote
• \\: Backslash

Example:

print("Hello\nWorld")  # prints Hello on one line and World on the next

String Interpolation:

Many modern languages support string interpolation, a way to embed variables directly within a string:

• Python (f-strings):

  name = "Alice"
  greeting = f"Hello, {name}!"

• JavaScript (template literals):

  let name = "Alice";
  let greeting = `Hello, ${name}!`;

Conclusion:

Strings are a foundational concept in programming, representing text data. Mastery of string manipulation is essential for tasks ranging from simple user interactions to data processing and beyond.

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