Why are symbols typically used as hash keys instead of strings?

Symbols are typically used as hash keys in Ruby for several reasons related to performance, immutability, and memory usage:

1. Immutability: Symbols are immutable, meaning once they are created, they cannot be altered. This immutability is beneficial for hash keys because it ensures that the key remains constant, and the integrity of the hash structure is maintained throughout the lifecycle of the application[1][2].

2. Memory Efficiency: When a symbol is created, it is stored in memory only once, and all subsequent uses of the symbol refer to the same memory address. This is unlike strings, where each new string—even if it has the same value—occupies a new memory location. Therefore, using symbols as hash keys can lead to significant memory savings, especially in applications where certain keys are repeatedly used[1][2][3].

3. Performance: The immutability and single storage location of symbols also contribute to faster performance when compared to strings. Since symbols are singleton objects (i.e., only one instance exists), comparing two symbols is very fast and is done by comparing their object IDs rather than their content. This is more efficient than comparing strings, which involves a character-by-character comparison[1][2][3].

4. Consistency and Safety: Using symbols as hash keys can prevent accidental modifications to keys. Since symbols are immutable, they cannot be changed inadvertently in the program, thus avoiding potential bugs and maintaining the consistency of hash keys[1][2].

5. Symbolic Representation: Symbols in Ruby are often semantically meaningful and represent names or labels within code. This makes them syntactically convenient for use as keys in hashes, where keys often serve as identifiers for values[1][2].

Despite these advantages, it's important to note that in recent Ruby versi...