Convert numbers between string, float, double, decimal

This code demonstrates the convertion of a float number string to various numeric data types, including Float, Double, Decimal, NSDecimalNumber in Swift Language.

The resulting values are then printed so you can see the precision loss of different data types.

swift

var str = "0.99999999"

if let f = Float(str) {
    print("str:\(str) Float:\(f)")
}
if let d = Double(str) {
    print("str:\(str) Double:\(d)")
}
if let dec = Decimal(string: str) {
    print("str:\(str) Decimal:\(dec)" )
    
}
let nsdec = NSDecimalNumber(string: str)
print("str:\(str) NSDecimalNumber:\(nsdec) NSDecimalNumber.floatValue:\(nsdec.floatValue) NSDecimalNumber.doubleValue:\(nsdec.doubleValue)")

var str = "0.99999999"

if let f = Float(str) {
    print("str:\(str) Float:\(f)")
}
if let d = Double(str) {
    print("str:\(str) Double:\(d)")
}
if let dec = Decimal(string: str) {
    print("str:\(str) Decimal:\(dec)" )
    
}
let nsdec = NSDecimalNumber(string: str)
print("str:\(str) NSDecimalNumber:\(nsdec) NSDecimalNumber.floatValue:\(nsdec.floatValue) NSDecimalNumber.doubleValue:\(nsdec.doubleValue)")

Results:

String	Float	Double	Decimal	NSDecimalNumber	.floatValue	.doubleValue
0.9	0.9	0.9	0.9	0.9	0.9	0.9
0.99	0.99	0.99	0.99	0.99	0.99	0.99
0.999	0.999	0.999	0.999	0.999	0.999	0.999
0.9999	0.9999	0.9999	0.9999	0.9999	0.9999	0.9998999999999999
0.99999	0.99999	0.99999	0.99999	0.99999	0.99999	0.99999
0.999999	0.999999	0.999999	0.999999	0.999999	0.999999	0.9999990000000001
0.9999999	0.9999999	0.9999999	0.9999999	0.9999999	0.9999999	0.9999998999999999
0.99999999	1.0	0.99999999	0.99999999	0.99999999	1.0	0.9999999899999998
0.999999999	1.0	0.999999999	0.999999999	0.999999999	1.0	0.9999999990000001
0.9999999999	1.0	0.9999999999	0.9999999999	0.9999999999	1.0	0.9999999999
0.99999999999	1.0	0.99999999999	0.99999999999	0.99999999999	1.0	0.9999999999900002
0.999999999999	1.0	0.999999999999	0.999999999999	0.999999999999	1.0	0.9999999999989999
0.9999999999999	1.0	0.9999999999999	0.9999999999999	0.9999999999999	1.0	0.0.9999999999999002
0.99999999999999	1.0	0.99999999999999	0.99999999999999	0.99999999999999	1.0	0.99999999999999
0.999999999999999	1.0	0.999999999999999	0.999999999999999	0.999999999999999	1.0	0.9999999999999991
0.9999999999999999	1.0	0.9999999999999999	0.9999999999999999	0.9999999999999999	1.0	1.0
0.99999999999999999	1.0	1.0	0.99999999999999999	0.99999999999999999	1.0	1.0
0.999999999999999999	1.0	1.0	0.999999999999999999	0.999999999999999999	1.0	1.0

Convert numbers between string, float, double, decimal ​

Convert numbers between string, float, double, decimal