Piye carane yield bisa gumana ing metode?

Question

IT Interview Practice · Accepted Answer

**`yield`** ngedhot **block** sing dipassake menyang metode — iku mindahake kontrol menyang block, opsional ngandhut nilai menyang iku, banjur mulai maneh metode. Iku carane metode ngedhot block sing wis diwenehake menyang iku, lan mekanisme konco ruby iteration lan akeh pola sing cakep.

## Dasar yield — ngedhot block sing wis diwenehake

```ruby
def greet
  puts "before"
  yield                    # calls the block passed to greet
  puts "after"
end

greet { puts "hello" }
# Output: before / hello / after
```

Yen metode ngedhot `yield`, iku njalani block sing wis dipassake menyang iku (ing `{ }` utawa `do...end`). Metode ngontrol *kapan* (lan sapirang kali) block njalani.

## yield karo argument — ngandhut nilai menyang parameter block

```ruby
def each_pair
  yield("a", 1)          # pass values to the block's parameters
  yield("b", 2)
end

each_pair { |key, value| puts "#{key}: #{value}" }
# Output: a: 1 / b: 2
```

`yield(args)` ngandhut nilai menyang parameter block (`|key, value|`) — iku carane method iterasi menehi saben elemen menyang block.

## Ngleksanani iterasi karo yield

```ruby
def my_each(array)
  i = 0
  while i < array.length
    yield(array[i])        # yield each element to the block
    i += 1
  end
end

my_each([1, 2, 3]) { |n| puts n * 2 }   # 2, 4, 6
# this is essentially how Array#each works internally!
```

Iku nuduhake carane method ruby iterasi (`each`, `map`, etc.) bisa gumana jero — iku `yield` saben elemen menyang block.

## block_given? lan ngagal block

```ruby
def maybe_yield
  if block_given?          # check whether a block was passed (avoid an error)
    yield
  else
    "no block"
  end
end

# explicitly capture the block as a parameter (with &)
def run(&block)            # &block captures the block as a Proc object
  block.call               # call it explicitly
end
```

`block_given?` nandani yen block wis dipassake (ngehindhari `LocalJumpError`), lan `&block` ngagal block minangka Proc obyek sing bisa disimpen utawa dipassake maneh.

## Kenapa iku penting

Paham `yield` iku ilmu ruby sing penting — iku mekanisme carane metode ngedhot block, sing dadi fondasi ruby signature iterasi lan akeh pola cakep, dadi nanggepi iku ndadangi carane akeh ruby bisa gumana. `yield` ngedhot block sing dipassake menyang metode (mindahake kontrol menyang iku, opsional ngandhut nilai), sing presise carane method ruby iterasi (`each`, `map`, `select`) bisa gumana jero — iku `yield` saben elemen menyang block.

Paham iki nggolehake misteri ruby iterasi blok lan nglidhake sampeyan **nulis metode sampeyan kang nggatari block** — kapabilitas kuat kanggo nggawe API sing ekspresif, iterator khusus, metode manajemen sumber daya (persiapan/pembersihan konco block), lan DSL.

Ngerti `yield` (ngedhot block, ngandhut argument menyang iku), `block_given?` (aman nandani apa block wis dipassake, ngehindhari kesalahan), lan `&block` (eksplisit ngagal block minangka Proc) penting kanggo paham carane ruby iterasi lan metode katanggap-blok bisa gumana lan kanggo nulis metode blok sampeyan.

Sukung block iku pusat ruby lan `yield` iku carane metode ngunakake iku, paham `yield` ndadangi pangerten deep carane ruby paling khas fitur (block) lan nglidhake sampeyan nulis jenis metode katanggap-blok cakep sing golekake ruby ekspresif — katrampilan berharga kanggo mbangun API resik lan topik interview umum sing menehi kuwat pangerten carane ruby mekanisme blok bisa gumana jero ilmu.

Dasar yield — ngedhot block sing wis diwenehake

yield karo argument — ngandhut nilai menyang parameter block

Ngleksanani iterasi karo yield

block_given? lan ngagal block

Kenapa iku penting

Pitakon sing gegandhengan