Parse a string of 4 numbers into a CGRect [closed] - ios

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I have this string (325, 140, 739, 979) . I want to parse it and take the four numbers separately.
This string represents a CGRect. I want to take the first number as x the second as y the third as width and the last as height.
What is the best way to achieve this ?

Answer 1

Given your string, you can fetch the numbers as an array of optional Int like this:
let str = "(325, 140, 739, 979)"
let nums = split(str) { contains("(), ", $0) }.map { $0.toInt() }
That split will remove any of the characters in the string passed to contains. You now have an array of optionals, which you can check for the correct contents:
let rect: CGRect
if nums.count == 4,
let x = nums[0], y = nums[1],
w = nums[2], h = nums[3]
{
rect = CGRect(x: x, y: y, width: w, height: h)
}
else {
// report an error, or default the values if you prefer
fatalError("Malformed input string")
}
Any extraneous characters in your input string will result in nil for one of the integers, or the wrong count in the array, so this should be safe against any garbage input.
For convenience, you could put all this in a failable initializer for CGRect:
extension CGRect {
init?(string: String) {
// note, since CGRect also has a contains method, need to specify Swift.contains
let nums = split(string) { Swift.contains("(), ", $0) }.map { $0.toInt() }
if nums.count == 4,
let x = nums[0], y = nums[1],
w = nums[2], h = nums[3]
{
self = CGRect(x: x, y: y, width: w, height: h)
}
else {
return nil
}
}
}
let rectangles = [
"(325, -140, 739, 979)", // valid
"(1,2,3,asdadaf)", // invalid (non-integer)
"1,2,3,4,", // valid
"(1,2,3,4,5)", // invalid (wrong count)
]
// returns an array of 2 valid CGRect and 2 nil
let cgrects = rectangles.map { CGRect(string: $0) }
Obviously there’s lots you could tweak here if you wanted to be more or less permissive in terms of the kind of input you’re willing to convert.

Answer 2

Here is my solution for your case:
func parse(str : String) -> [Int] {
var firstStepStr = str.stringByTrimmingCharactersInSet(NSCharacterSet(charactersInString: "()")) //remove ( and )
var secondStepArray = firstStepStr.componentsSeparatedByCharactersInSet(NSCharacterSet(charactersInString: ", ")).filter{$0 != ""} //separated by , and ignore ""
return secondStepArray.map{$0.toInt() ?? 0} //convert to [Int], if cannot convert to Int, return 0
}
let cgrectString = "(325, 140, 739, 979)"
let intArray = parse(cgrectString)

Answer 3

First, we could get rid of the parentheses
let myString = "(325, 140, 739, 979)"
let myReplacementString = String(map(myString.generate()) {
$0 == "(" || $0 == ")" ? "-" : $0
})
You could also take a substring, which doesn't seem to be any nicer.
Then we could split the string into array
var myArray = myReplacementString.componentsSeparatedByString(", ")
And then use a loop to cast string to int
for item in myArray {
item.toInt()
}
or just use myArray[i].toInt() to give them straight to constructor etc.

Answer 4

This will get you an array of the four CGFloat values you are looking for:
func stringToCGFloatArray(string: String) -> [CGFloat] {
return string.componentsSeparatedByCharactersInSet(
NSCharacterSet(charactersInString: "(), ")).reduce([CGFloat]()) {
if let x = $1.toInt() {
return $0 + [CGFloat(x)]
} else {
return $0
}
}
}
You can then convert it to an optional tuple that can be provided directly to CGMakeRect:
func arrayToRectParameters(array: [CGFloat]) -> (CGFloat, CGFloat, CGFloat, CGFloat)? {
switch array.count {
case 4:
return (array[0], array[1], array[2], array[3])
default:
return nil
}
}
Now you can create a CGRect like this:
let str = "(325, 140, 739, 979)"
if let rectParameters = arrayToRectParameters(stringToCGFloatArray(str)) {
let myCGRect = CGRectMake(rectParameters)
println(myCGRect) // prints (325.0,140.0,739.0,979.0)
}