How to Remove Key-Value Pairs from a Dictionary Based on Values in Swift - Step by Step Examples

How to Remove Key-Value Pairs from a Dictionary Based on Values in Swift ?

Answer

To remove key-value pairs from a dictionary based on values in Swift, you can use the `filter` method to create a new dictionary without the pairs that match the specified value or iterate through the dictionary to remove the pairs directly.

✐ Examples

1 Removing Key-Value Pairs Based on Values Using the `filter` Method

We can remove key-value pairs from a dictionary in Swift based on their values using the `filter` method to create a new dictionary without the pairs that match the specified value. This example demonstrates how to achieve this and print the dictionary contents before and after the removal.

For example,

We start by declaring and initializing a dictionary named myDictionary with integer keys and string values.
We print the dictionary contents before removing key-value pairs.
We use the `filter` method to create a new dictionary without the pairs that match the specified value.
We print the dictionary contents after removing the key-value pairs.

Swift Program

var myDictionary: [Int: String] = [
    1: "One",
    2: "Two",
    3: "Three",
    4: "Two"
]

// Print the dictionary contents before removal
print("Dictionary contents before removal:")
for (key, value) in myDictionary {
    print("Key: \(key), Value: \(value)")
}

// Value to remove
let valueToRemove = "Two"

// Remove key-value pairs based on value using the filter method
myDictionary = myDictionary.filter { $0.value != valueToRemove }

// Print the dictionary contents after removal
print("Dictionary contents after removal:")
for (key, value) in myDictionary {
    print("Key: \(key), Value: \(value)")
}

Output

Dictionary contents before removal:
Key: 1, Value: One
Key: 2, Value: Two
Key: 3, Value: Three
Key: 4, Value: Two
Dictionary contents after removal:
Key: 1, Value: One
Key: 3, Value: Three

2 Removing Key-Value Pairs Based on Values Using Iteration

We can remove key-value pairs from a dictionary in Swift based on their values using iteration to identify and remove pairs that match the specified value. This example demonstrates how to achieve this and print the dictionary contents before and after the removal.

For example,

We start by declaring and initializing a dictionary named myDictionary with integer keys and string values.
We print the dictionary contents before removing key-value pairs.
We use iteration to identify and remove pairs that match the specified value.
We print the dictionary contents after removing the key-value pairs.

Swift Program

var myDictionary: [Int: String] = [
    1: "One",
    2: "Two",
    3: "Three",
    4: "Two"
]

// Print the dictionary contents before removal
print("Dictionary contents before removal:")
for (key, value) in myDictionary {
    print("Key: \(key), Value: \(value)")
}

// Value to remove
let valueToRemove = "Two"

// Identify keys to remove
let keysToRemove = myDictionary.filter { $0.value == valueToRemove }.map { $0.key }

// Remove identified keys
for key in keysToRemove {
    myDictionary.removeValue(forKey: key)
}

// Print the dictionary contents after removal
print("Dictionary contents after removal:")
for (key, value) in myDictionary {
    print("Key: \(key), Value: \(value)")
}

Output

Dictionary contents before removal:
Key: 1, Value: One
Key: 2, Value: Two
Key: 3, Value: Three
Key: 4, Value: Two
Dictionary contents after removal:
Key: 1, Value: One
Key: 3, Value: Three

Summary

In this tutorial, we learned How to Remove Key-Value Pairs from a Dictionary Based on Values in Swift language with well detailed examples.

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How to Remove Key-Value Pairs from a Dictionary Based on Values in Swift - Step by Step Examples