How to handle json error in loop or stop it - ios

Question

I have the following code that populates a UITableView. The end var holds the number of items in the JSON response. I concatenate variable n with the counter i. My problem is that in this case the JSON response carries only two items, Request1 and Request2. When the counter reaches 3 the app crashes because there is no Request3. How can I change my loop to stop when the condition counter > end is met?
let jsonData = try NSJSONSerialization.JSONObjectWithData(urlData!, options: .MutableContainers) as? NSDictionary
var end = jsonData!["num"]!
var i = 0
var n = "Request"
for item in jsonData! {
i++
n = "Request"+String(i)
var result = jsonData![n] as? NSDictionary
if let Name = result!["Name"] as? String
{
Names.append(Name)
print(Name)
}
if let Date = result!["Request_Id"] as? String
{
Dates.append(Date)
print(Date)
}
}

Answer 1

Try the following:
let jsonData = try NSJSONSerialization.JSONObjectWithData(urlData!, options: .MutableContainers) as? NSDictionary
var end = jsonData!["num"]!
var i = 0
var n = "Request"
for item in jsonData! {
i++
// This should do it
if i == end {
break;
}
n = "Request"+String(i)
var result = jsonData![n] as? NSDictionary
if let Name = result!["Name"] as? String
{
Names.append(Name)
print(Name)
}
if let Date = result!["Request_Id"] as? String
{
Dates.append(Date)
print(Date)
}
}
I'm assuming that by counter > end you mean i > end, as it's what seems to make sense to me.

Answer 2

Try starting your counter i with 1 rather than 0 incrementing it at the end of the loop like this:
let jsonData = try NSJSONSerialization.JSONObjectWithData(urlData!, options: .MutableContainers) as? NSDictionary
var end = jsonData!["num"]!
var i = 0
var n = "Request"
for item in jsonData! {
i++;
if(i==end)break;
n = "Request"+String(i)
var result = jsonData![n] as? NSDictionary
if let Name = result!["Name"] as? String
{
Names.append(Name)
print(Name)
}
if let Date = result!["Request_Id"] as? String
{
Dates.append(Date)
print(Date)
}
}
Also you can consider the following way of doing it
let jsonData = try NSJSONSerialization.JSONObjectWithData(urlData!, options: .MutableContainers) as? NSDictionary
var end = jsonData!["num"]!
var i = 0
var n = "Request"
while(i<end) { //since we are iterating on the basis on the number and specific hardcoded keys of jsondata (and not item) we can just use a normal while loop
i++;
n = "Request"+String(i)
var result = jsonData![n] as? NSDictionary
if let Name = result!["Name"] as? String
{
Names.append(Name)
print(Name)
}
if let Date = result!["Request_Id"] as? String
{
Dates.append(Date)
print(Date)
}
}