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iOS

Tuan Do
Tuan Do
3,495 Points
Posted by Tuan Do
Tuan Do
3,495 Points

Optional binding chaining

What's the difference between the two code snippets below or are they equivalent?

if let currentWeather = forecast?.currentWeather {
}

and

if let weatherForecast = forecast, let currentWeather = weatherForecast.currentWeather {
}

1 Answer

Jhoan Arango
Jhoan Arango
13,603 Points

Hello:

Yes, they are equivalent, it's just that one is shorter than the other. 

/* 
This one is going straight to the currentWeather,
by calling forecast?.currentWeather. This will return current weather
*/

if let currentWeather = forecast?.currentWeather {
}

and 

/*
This one is doing a second step by first getting forecast 
and assigning it to weatherForecast, and then we get
currentWeather with the dot notation. "weatherForecast.currentWeather"
*/

if let weatherForecast = forecast, let currentWeather = weatherForecast.currentWeather {
}

Anything you don't understand, let me know and I can clarify it better.

Good luck

Tuan Do
Tuan Do
3,495 Points
Tuan Do
Tuan Do
3,495 Points

That makes sense. Thanks!