How to Iterate Over a Dictionary of Dictionaries in Swift

How to Iterate Over a Dictionary of Dictionaries in Swift ?

Answer

To iterate over a dictionary of dictionaries in Swift, you can use nested `for` loops to iterate through both the outer dictionary and the inner dictionaries. This allows you to access and process each key-value pair in the nested dictionaries.


✐ Examples

1 Iterating Over a Dictionary of Dictionaries Using Nested `for` Loops

We can iterate over a dictionary of dictionaries in Swift using nested `for` loops. This example demonstrates how to declare and initialize a dictionary of dictionaries, use nested `for` loops to iterate through the outer and inner dictionaries, and print each key-value pair.

For example,

  1. We start by declaring and initializing a dictionary of dictionaries named outerDict with string keys and integer values.
  2. We use nested `for` loops to iterate through the outer and inner dictionaries.
  3. We print each key-value pair.

Swift Program

var outerDict: [String: [String: Int]] = [
    "A": ["X": 1, "Y": 2],
    "B": ["Z": 3]
]

// Iterate over the dictionary of dictionaries using nested for loops
print("Iterating over dictionary of dictionaries:")
for (outerKey, innerDict) in outerDict {
    print("Outer Key: \(outerKey)")
    for (innerKey, value) in innerDict {
        print("  Inner Key: \(innerKey), Value: \(value)")
    }
}

Output

Iterating over dictionary of dictionaries:
Outer Key: A
  Inner Key: X, Value: 1
  Inner Key: Y, Value: 2
Outer Key: B
  Inner Key: Z, Value: 3

2 Iterating Over a Dynamically Created Dictionary of Dictionaries

We can iterate over a dynamically created dictionary of dictionaries in Swift using nested `for` loops. This example demonstrates how to declare a dictionary of dictionaries, add inner dictionaries dynamically, add key-value pairs to the inner dictionaries, use nested `for` loops to iterate through the outer and inner dictionaries, and print each key-value pair.

For example,

  1. We start by declaring a dictionary of dictionaries named outerDict.
  2. We add inner dictionaries dynamically and add key-value pairs to the inner dictionaries.
  3. We use nested `for` loops to iterate through the outer and inner dictionaries.
  4. We print each key-value pair.

Swift Program

var outerDict: [String: [String: Int]] = [:]

// Add inner dictionaries dynamically
outerDict["A"] = [:]
outerDict["B"] = [:]

// Add key-value pairs to the inner dictionaries
outerDict["A"]?["X"] = 1
outerDict["A"]?["Y"] = 2
outerDict["B"]?["Z"] = 3

// Iterate over the dictionary of dictionaries using nested for loops
print("Iterating over dictionary of dictionaries:")
for (outerKey, innerDict) in outerDict {
    print("Outer Key: \(outerKey)")
    for (innerKey, value) in innerDict {
        print("  Inner Key: \(innerKey), Value: \(value)")
    }
}

Output

Iterating over dictionary of dictionaries:
Outer Key: A
  Inner Key: X, Value: 1
  Inner Key: Y, Value: 2
Outer Key: B
  Inner Key: Z, Value: 3

Summary

In this tutorial, we learned How to Iterate Over a Dictionary of Dictionaries in Swift language with well detailed examples.


More Swift Dictionaries Tutorials

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  2. How to create a Dictionary with Initial Key-Value Pairs in Swift ?
  3. How to Print a Dictionary in Swift ?
  4. How to Add a Key-Value Pair to a Dictionary in Swift ?
  5. How to Set a Default Value for a Key in a Dictionary in Swift ?
  6. How to Update the Value for a Key in a Dictionary in Swift ?
  7. How to Check if a Dictionary is Empty in Swift ?
  8. How to Check if a Key Exists in a Dictionary in Swift ?
  9. How to Check if a Value Exists in a Dictionary in Swift ?
  10. How to Get the Value Associated with a Key in a Dictionary in Swift ?
  11. How to Remove a Key-Value Pair from a Dictionary in Swift ?
  12. How to Remove Key-Value Pairs from a Dictionary Based on Values in Swift ?
  13. How to Clear all Key-Value Pairs from a Dictionary in Swift ?
  14. How to Iterate over Keys in a Dictionary in Swift ?
  15. How to Iterate over Values in a Dictionary in Swift ?
  16. How to Iterate over Entries (Key-Value Pairs) in a Dictionary in Swift ?
  17. How to Get the Size (Number of Key-Value Pairs) of a Dictionary in Swift ?
  18. How to Convert a Dictionary to an Array of Keys in Swift ?
  19. How to Convert a Dictionary to an Array of Values in Swift ?
  20. How to Convert a Dictionary to an Array of Key-Value Pairs in Swift ?
  21. How to Merge Two Dictionaries in Swift ?
  22. How to Clone a Dictionary in Swift ?
  23. How to Check if Two Dictionaries are Equal in Swift ?
  24. How to Sort a Dictionary by Keys in Swift ?
  25. How to Sort a Dictionary by Values in Swift ?
  26. How to Filter a Dictionary Based on Keys in Swift ?
  27. How to Filter a Dictionary Based on Values in Swift ?
  28. How to Reduce Values in a Dictionary to a Single Value in Swift ?
  29. How to Convert an Array of Key-Value Pairs to a Dictionary in Swift ?
  30. How to Convert a Dictionary to a JSON String in Swift ?
  31. How to Convert a JSON String to a Dictionary in Swift ?
  32. How to Swap Keys and Values in a Dictionary in Swift ?
  33. How to Create a Dictionary of Dictionaries in Swift ?
  34. How to Iterate Over a Dictionary of Dictionaries in Swift ?