String Manipulation

Understanding String Manipulation

String Basics

  • A string is a sequence of characters; it can include letters, numbers, and other types of characters.
  • Strings in most programming languages are enclosed in quotes. Single (' ') or double (" ") quotes are commonly used.

String Concatenation

  • String concatenation is the operation of joining two or more strings end-to-end.
  • In many languages, the + operator is used for string concatenation.

String Length

  • The length of a string is the number of characters it contains.
  • Many languages provide a built-in function (often called len or length) to return the number of characters in a string.

Substrings

  • A substring is a sequence of characters within a string.
  • Substrings can be accessed using indices, which specify positions of characters within the string.

String Methods

  • String methods are built-in functions that perform operations on strings.
  • Some commonly used methods include toUpperCase, toLowerCase, trim etc. which respectively convert string to all upper case, all lower case, and removes leading and trailing spaces.

String Comparison

  • Strings can be compared in programming languages to evaluate their similarity or difference.
  • Equal operator == is commonly used to check if two strings are identical, and != to check if they are not identical.
  • Comparison operators, such as <, >, <=, and >=, can be used to compare strings lexicographically, i.e., based on the alphabetical order of their characters.

String Immutability

  • Strings are usually immutable, meaning that once a string is created, it cannot be changed.
  • In practice, when a string appears to be modified, a new string is actually created to reflect the change.

Escaping Characters

  • Special characters in strings, such as quotes and backslashes, can be preceded by a backslash (\) to escape them, i.e., to indicate that they should be interpreted literally rather than as special characters.
  • For instance, to include a double quote within a string that is enclosed with double quotes, you would write it as \".

Key Takeaway

  • String manipulation is an essential aspect of programming that involves working with text. Understanding how to manipulate, compare, and evaluate strings is vital for tasks like input validation, data parsing, and more.