convert samoa time to gmt in swift

To convert Samoa time (SST) to Greenwich Mean Time (GMT) in Swift, follow these steps:

1. Create instances of DateFormatter and Date classes.

2. Set the timeZone property of the DateFormatter instance to the Samoa timezone (Pacific/Apia).

3. Set the dateFormat property of the DateFormatter instance to the appropriate date format string that matches the input date's format.

4. Create a string that represents the Samoa time.

5. Use the date(from:) method of the DateFormatter instance to convert the string to a Date object.

6. Create a Calendar instance and set its timeZone property to the GMT timezone (GMT).

7. Use the dateComponents(in:) method of the Calendar instance to get the date and time components of the Samoa time in the GMT timezone.

8. Create a new string from the GMT time components using a DateFormatter instance with the appropriate date format string.

Here's the Swift code for this:

main.swift
let dateFormatter = DateFormatter()
dateFormatter.timeZone = TimeZone(identifier: "Pacific/Apia")
dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"

let samoaTimeStr = "2022-03-15 10:00:00"
guard let samoaTime = dateFormatter.date(from: samoaTimeStr) else { return }

let gmtCalendar = Calendar(identifier: .gregorian)
gmtCalendar.timeZone = TimeZone(identifier: "GMT")!

let gmtComponents = gmtCalendar.dateComponents(in: TimeZone(identifier: "GMT")!,
                                                 from: samoaTime)

let gmtDateFormatter = DateFormatter()
gmtDateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
let gmtTimeStr = gmtDateFormatter.string(from: gmtComponents.date!)

print("Samoa time: \(samoaTimeStr)")
print("GMT time: \(gmtTimeStr)")
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This code assumes that the input Samoa time is in the format "yyyy-MM-dd HH:mm:ss". You may need to adjust the dateFormat property of the DateFormatter instance to match your specific input format.