How to create a string with format? Not working on string

Question

Lots of details on this throughout SO and online. Unfortunately, I cannot get any of it to work to with my string. I have this string

 https://maps.googleapis.com/maps/api/directions/json?origin=%@,%@&destination=%@,%@&sensor=false&units=metric&mode=driving

And all I'm trying to do is insert the necessary values into the string by doing

 let url = String(format: Constants.GoogleDirectionsUrl, road.FromCoordinates.Latitude, road.FromCoordinates.Longitude, road.ToCoordinates.Latitude, road.ToCoordinates.Longitude)

The string though always prints out as

https://maps.googleapis.com/maps/api/directions/json?origin=(null),(null)&destination=(null),(null)&sensor=false&units=metric&mode=driving

Although all the coordinates are valid. When I do string interpolation I get the correct value to show up

print("coord -- \(road.FromCoordinates.Latitude)")

coord -- 29.613929

I've tried %l, %f and %@ in the string all with the same results. Anyone see what it is I'm doing incorrect here?

Update

For anyone else, here is what I ended up doing to overcome the above. I followed the answer below a bit and created a class func that I have in one of the global classes in the app. This allows me to call it from any where. Here is the function

 class func createUrlDrivingDiretions (sLat: Double, sLon: Double, eLat: Double, eLon: Double) -> String {
    return "https://maps.googleapis.com/maps/api/directions/json?origin=\(sLat),\(sLon)&destination=\(eLat),\(eLon)&sensor=false&units=metric&mode=driving"
}

Update your question with the declaration and setting of all variables involved in this question. — rmaddy
– rmaddy, Commented Nov 18, 2016 at 15:06

Sergio B. · Accepted Answer · 2016-11-18 15:40:00Z

3

Why don't you use the following syntax (use Swift... not legacy obj-c coding):

let var1 = "xxx"
let var2 = "yyy"
let var3 = "zzz"
let var4 = "www"
let var5 = "kkk"

let s = "https://maps.googleapis.com/maps/api/directions/json?origin=\(var1),\(var2)&destination=\(var4),\(var5)&sensor=false&units=metric&mode=driving"

Make sure var1... var5 are not optional otherwise you have to unwrap them or you'll get something like this in the output string: Optional(xxx)... instead of xxx

If you need special formatting use NumberFormatter (see this: Formatters)

edited Nov 18, 2016 at 15:40

answered Nov 18, 2016 at 15:13

Sergio B.

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2 Comments

Micah Montoya Over a year ago

Unfortunately, something like this wouldn't work. I'm not looking at including the url in the class considering it will be used in numerous places. This would require duplicating code which I generally avoid.

Micah Montoya Over a year ago

So, following this a bit I created a function in one of the global classes I have so that I can just call it from any where. Thanks for the tip.

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