Tofauti kati ya strings na symbols ni ipi?

Question

Accepted Answer

**Strings** ni mfululizo wa herufi unaobadilika (mutable); **symbols** (`:name`) ni vitambulisho visivyobadilika (immutable), vilivyo **interned** — symbol ileile ni object yaleyale halisi kwenye memory kila mahali. Symbols hutumika kama vitambulisho vyepesi na vyenye ufanisi (hasa hash keys), ilhali strings hushikilia data halisi ya maandishi.

## Tofauti ya msingi: utambulisho na ubadilikaji

```ruby
# strings — each is a NEW object (even with the same content)
"hello".object_id == "hello".object_id    # false — two different objects
"hello" << " world"                        # mutable — can be modified in place

# symbols — the SAME symbol is always the SAME object (interned)
:hello.object_id == :hello.object_id       # true — identical object every time
:hello.frozen?                              # true — symbols are immutable
```

Kila string literal inaunda object mpya, lakini symbol ni **interned** — `:hello` daima ni object yaleyale halisi kwenye memory, bila kujali inajitokeza mara ngapi. Symbols pia hazibadiliki.

## Faida za memory na utendaji za symbols

```text
Strings: each "name" allocates a new object → more memory, slower comparison (char by char)
Symbols: :name is ONE shared object → memory-efficient, fast comparison (by identity)
→ Symbols are ideal as identifiers used repeatedly (hash keys, method names, options).
```

## Lini kutumia ipi

```ruby
# SYMBOLS — for identifiers: hash keys, method names, options, fixed labels
user = { name: "Ann", role: :admin }       # symbol keys (the idiom)
send(:upcase)                               # method name as a symbol
status = :active                            # a fixed label/state

# STRINGS — for actual text DATA that you display, manipulate, or that varies
name = "Ann Smith"                          # real text content
message = "Hello, #{name}"                  # building/interpolating text
user_input = gets.chomp                     # data from outside
```

Tumia **symbols kwa vitambulisho** (hash keys, option names, states, method names — labels zilizosimama, zinazorudiwa) na **strings kwa data halisi ya maandishi** (maudhui unayoyaonyesha, kuyadhibiti, au yanayotoka kwa watumiaji).

## Kubadilisha kati yao

```ruby
"hello".to_sym    # :hello
:hello.to_s        # "hello"
```

## Kwa nini ni muhimu

Kuelewa tofauti ya string-dhidi-ya-symbol ni maarifa muhimu na ya kipekee ya Ruby, kwa kuwa symbols ni kipengele ambacho lugha nyingine nyingi hazina, na kuzitumia ipasavyo ni Ruby ya kiidiomu.

Tofauti muhimu ni kwamba **symbols ni interned na immutable** (`:name` daima ni object ileile moja kwenye memory, isiyobadilika), ilhali **strings zinabadilika na kila literal ni object mpya**.

Hii inawapa symbols **faida za memory na utendaji** kama vitambulisho: huwekwa mara moja na kushirikiwa (zenye ufanisi wa memory zikitumika mara kwa mara), na zinalinganishwa kwa utambulisho (haraka) badala ya herufi-kwa-herufi.

Mwongozo wa kivitendo — **tumia symbols kwa vitambulisho** (hash keys, method names, option labels, states zilizosimama — vitu vinavyotumika mara kwa mara kama labels) na **strings kwa data halisi ya maandishi** (maudhui unayoyaonyesha, kuyadhibiti, au kupokea kutoka kwa watumiaji) — ni Ruby muhimu ya kiidiomu inayoathiri utendaji na uwazi.

Symbol hash keys (`{ name: "Ann" }`) ni desturi katika Ruby na Rails, na kutumia symbols kwa vitambulisho vilivyosimama badala ya strings ni kwa ufanisi na kawaida.

Kuelewa lini kutumia kila moja, interning/immutability ya symbols, na ufanisi wao kama vitambulisho ni maarifa ya msingi, yanayotumika mara kwa mara ya Ruby — ni hoja ya kawaida ya mkanganyiko kwa wapya (kwa nini kuwa na vyote viwili?), na kufahamu tofauti (symbols kama vitambulisho vyenye ufanisi vilivyo interned, strings kama data ya maandishi inayobadilika) ni muhimu kwa kuandika Ruby ya kiidiomu, yenye ufanisi na mada ya mahojiano ya mara kwa mara inayoonyesha uelewa wa kipengele hiki cha kipekee cha Ruby.