NumberFormatter

NumberFormatter is a class that provides a flexible and easy way to convert numbers into strings and vice versa.
It is a part of the Foundation framework and is available on all Apple platforms.
In this post, we will explore the various ways in which we can use NumberFormatter to format numbers in Swift.

What Styles does NumberFormatter have?

Force a specific locale

By default, NumberFormatter uses the current locale of the device.
You can force a specific locale by setting the locale property of the NumberFormatter class.

let numberFormatter = NumberFormatter()
numberFormatter.locale = Locale(identifier: "nl_NL")
print(numberFormatter.string(from: 1000)!) // prints "1000" in the Dutch locale

Use Cases

Formatting Numbers

One of the most common use cases for NumberFormatter is to format numbers.
This can be done using the numberStyle property of the NumberFormatter class.

let numberFormatter = NumberFormatter()
numberFormatter.numberStyle = .decimal
print(numberFormatter.string(from: 1000)!) // prints "1,000" in the US locale, "1000" in the Dutch locale

Number to Words (Spell Out)

Another case for NumberFormatter is to convert a number into a string.
This can be done using the string(from: Number) function.

let numberFormatter = NumberFormatter()
numberFormatter.numberStyle = .spellOut
print(numberFormatter.string(from: 1990)!) // prints "one thousand nine hundred ninety"

Currency

Another use case for NumberFormatter is to format numbers as currency. .
This can be done using the currencySymbol and currencyCode properties of the NumberFormatter class.

let numberFormatter = NumberFormatter()
numberFormatter.numberStyle = .currency
numberFormatter.currencyCode = "EUR"
print(numberFormatter.string(from: 10)!) // prints "€10.00"

Conclusion

NumberFormatter is a powerful class that provides a flexible and easy way to convert numbers into strings and vice versa.
It supports a wide range of styles and locales, making it suitable for a variety of use cases.
Whether you need to format numbers, convert numbers to words, or display numbers as currency, NumberFormatter has you covered.

Resources:

• https://developer.apple.com/documentation/foundation/numberformatter

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