Swift: Dictionary filtering

Swift: Dictionary filtering

Filtering dictionaries in Swift allows you to create a new dictionary containing only the key-value pairs that meet certain conditions. This is useful for extracting relevant data or cleaning up dictionaries based on your criteria.

Code

// Original dictionary with fruit names and their quantities
let fruitInventory = [
  "apple": 10,
  "banana": 5,
  "orange": 8,
  "pear": 0
]

// Filter dictionary to include only fruits with quantity greater than 0
let availableFruits = fruitInventory.filter { (key, value) in
  value > 0
}

// availableFruits is ["apple": 10, "banana": 5, "orange": 8]
print(availableFruits)

// You can also filter by keys, for example fruits starting with "a"
let fruitsStartingWithA = fruitInventory.filter { key, _ in
  key.hasPrefix("a")
}

// fruitsStartingWithA is ["apple": 10]
print(fruitsStartingWithA)

Key Points

• The filter method on dictionaries returns a dictionary containing only the key-value pairs that satisfy the given condition.
• You can filter based on keys, values, or both using a closure that takes (key, value) as parameters.
• Filtering does not modify the original dictionary but returns a new filtered dictionary.
• Use conditions like value comparisons or string methods on keys to customize filtering.