Text Processing Chapter 9 Quiz

Wrapper Classes

• Wrapper classes are classes that encapsulate primitive data types, allowing the creation of objects instead of just variables.
• They provide methods to perform operations related to the encapsulated primitive type and are immutable.
• Java defines wrapper classes for each primitive data type, including Byte, Double, Float, Integer, Long, and Short.

Primitive Data Types

• Primitive data types are basic data types that are not objects and do not possess attributes or methods.
• These types include byte, double, float, int, long, and short.

Character Class

• The Character Class serves as a wrapper for the char data type and offers methods for character testing and conversion.

Character Testing Methods

• isDigit(char ch): Checks if the character is a digit (0-9).
• isLetter(char ch): Verifies if the character is an alphabetic letter.
• isLetterOrDigit(char ch): Returns true for characters that are either digits or letters.
• isLowerCase(char ch): Checks if the character is a lowercase letter.
• isUpperCase(char ch): Checks if the character is an uppercase letter.
• isSpaceChar(char ch): Identifies if the character is a space character.
• isWhiteSpace(char ch): Identifies if the character is any whitespace character (space, tab, newline).

String Manipulation Methods

• substring(int start): Extracts a substring from a specified starting index to the end of the string.
• substring(int start, int end): Returns a substring from start to end (end is exclusive).
• concat(String str): Combines the contents of the calling string with another string.
• trim(): Eliminates leading and trailing whitespace characters.

String Search Methods

• indexOf(char ch): Locates the first occurrence of a character within the string, returning its index or -1 if not found.
• lastIndexOf(char ch): Finds the last occurrence of a character, searching from the end of the string.

String Comparison Methods

• startsWith(String str): Verifies if the string begins with the specified prefix.
• endsWith(String str): Confirms if the string ends with the specified suffix.
• regionMatches(...): Compares specific regions of two strings for equality.

StringBuilder and StringBuffer

• The StringBuilder class allows modification of string contents and provides additional methods compared to String.
• StringBuffer methods are synchronized for thread safety, while StringBuilder methods are not.

Tokenization

• Tokenizing is the act of breaking a string into components called tokens, often using the String class's split method.
• The delimiter is a character that separates tokens.

Regular Expressions

• Regular expressions specify patterns of characters and can be used to search for those patterns within strings and other text collections.

Autoboxing and Unboxing

• Autoboxing is the automatic conversion of primitive values into their corresponding wrapper objects.
• Unboxing is the reverse process, converting wrapper objects back into their primitive types.

Static Members and Constants

• MIN_VALUE and MAX_VALUE are static final variables representing the minimum and maximum values for respective data types.

CSV File Format

• Comma Separated Value (CSV) format is used when exporting data from Excel, where rows correspond to lines and cell values are delineated by commas.
• Files saved in this format use the .csv extension.