Dev Blog

Summary ​

Conclusions ​

An array stores a fixed number of elements of one type, accessed by zero-based indices; indices from the end ^n and ranges a[x..y] simplify working with the end and portions of an array. An array is a reference type, so assignment copies the reference; use Clone or Array.Copy to create an independent copy. The Array class provides methods for sorting, searching, filling, and resizing. Store tabular data in rectangular arrays T[,] and rows of different lengths in jagged arrays T[][]. A string is an immutable sequence of char characters: its methods return new strings, comparisons use the selected StringComparison, and StringBuilder is used to build large strings in loops. For Ukrainian text, consider culture when sorting and normalize apostrophes.

Self-check questions ​

  1. What is an array? How do you create one using a collection expression and the new operator?
  2. What values do array elements have after new double[10]?
  3. What do a[^1], a[1..^1], and a[..3] mean?
  4. Why does b = a not copy the array? How do you create a copy?
  5. How does == compare arrays?
  6. Which Array class methods do you know? What is required to use BinarySearch?
  7. How does Array.Resize work? Does it change the length of the existing array?
  8. How does a rectangular array differ from a jagged array? How do you find their dimensions?
  9. What does string immutability mean? What are its consequences?
  10. How do Ordinal, OrdinalIgnoreCase, and CurrentCulture comparisons differ?
  11. How do you split a string into parts and discard empty parts?
  12. How do regular, verbatim, interpolated, and raw string literals differ?
  13. What is the StringBuilder class for? When should you use it?
  14. Why does sorting Ukrainian words by character codes produce the wrong order?
  15. What are regular expressions used for?