Rounding a double value (1.005) to (1.01)

Question

Problem with rounding the number 1.005 in swift

rounding 1.005 to two decimal places results in 1.0 instead of 1.01 how to solve it?

for i in 1..<11 {
    let value = Double(i) + 0.005
    let roundedValue = round(value * 100) / 100.0
    print(value, roundedValue)
}

Output:

1.005  -> 1.0
2.005  -> 2.01
3.005  -> 3.01
4.005  -> 4.01
5.005  -> 5.01
6.005  -> 6.01
7.005  -> 7.01
8.005  -> 8.01
9.005  -> 9.01
10.005  -> 10.01

Use String(format: ) and convert the string back into Double. — El Tomato, Apr 19 '21 at 13:21

score 1 · Accepted Answer · answered Apr 19 '21 at 13:26

Just use a NumberFormatter and set the roundingMode to halfUp:

extension Formatter {
    static let number: NumberFormatter = {
        let formatter = NumberFormatter()
        formatter.numberStyle = .decimal
        formatter.minimumFractionDigits = 2
        formatter.maximumFractionDigits = 2
        formatter.roundingMode = .halfUp
        return formatter
    }()
}

Formatter.number.string(for: 1.005)   // "1.01"
Formatter.number.string(for: 2.005)   // "1.01"
Formatter.number.string(for: 3.005)   // "1.01"
Formatter.number.string(for: 4.005)   // "1.01"
Formatter.number.string(for: 5.005)   // "1.01"
Formatter.number.string(for: 6.005)   // "1.01"
Formatter.number.string(for: 7.005)   // "1.01"
Formatter.number.string(for: 8.005)   // "1.01"
Formatter.number.string(for: 9.005)   // "1.01"
Formatter.number.string(for: 10.005)  // "1.01"

Rounding a double value (1.005) to (1.01)

1 Answers1