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Why can't I use the try? in swift
try, try! & try? what’s the difference, and when to use each?How to call Objective-C code from Swift#ifdef replacement in the Swift language@selector() in Swift?#pragma mark in Swift?How can I extend typed Arrays in Swift?Swift for loop: for index, element in array?Swift Beta performance: sorting arraysSwift do-try-catch syntaxSwift 2: Call can throw, but it is not marked with 'try' and the error is not handledexception handling with swift
.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty height:90px;width:728px;box-sizing:border-box;
Use try? to handling the error in the function
But it shows that "No calls to throwing functions occur within 'try' expression"
if let result:Double = try? finalformular.expression.expressionValue(with: nil, context: nil) as! Double
text = String(result)
else
text = "Error"
enter image description here
swift
asked Mar 23 at 7:34
Nick ShernNick Shern
11
add a comment |
Use try? to handling the error in the function
But it shows that "No calls to throwing functions occur within 'try' expression"
if let result:Double = try? finalformular.expression.expressionValue(with: nil, context: nil) as! Double
text = String(result)
else
text = "Error"
enter image description here
swift
asked Mar 23 at 7:34
Nick ShernNick Shern
11
1
expressionValue(with:, context:)really throws? What's its declaration? Seems to be developer.apple.com/documentation/foundation/nsexpression/… there is no "throws", so no reason to do a try.
– Larme
Mar 23 at 7:38
1
Possible duplicate of try, try! & try? what’s the difference, and when to use each?
– El Tomato
Mar 23 at 7:41
add a comment |
Use try? to handling the error in the function
But it shows that "No calls to throwing functions occur within 'try' expression"
if let result:Double = try? finalformular.expression.expressionValue(with: nil, context: nil) as! Double
text = String(result)
else
text = "Error"
enter image description here
swift
asked Mar 23 at 7:34
Nick ShernNick Shern
11
Use try? to handling the error in the function
But it shows that "No calls to throwing functions occur within 'try' expression"
if let result:Double = try? finalformular.expression.expressionValue(with: nil, context: nil) as! Double
text = String(result)
else
text = "Error"
enter image description here
swift
swift
asked Mar 23 at 7:34
Nick ShernNick Shern
11
asked Mar 23 at 7:34
Nick ShernNick Shern
11
asked Mar 23 at 7:34
Nick ShernNick Shern
11
asked Mar 23 at 7:34
Nick ShernNick Shern
11
asked Mar 23 at 7:34
Nick ShernNick Shern
11
11
1
expressionValue(with:, context:)really throws? What's its declaration? Seems to be developer.apple.com/documentation/foundation/nsexpression/… there is no "throws", so no reason to do a try.
– Larme
Mar 23 at 7:38
1
Possible duplicate of try, try! & try? what’s the difference, and when to use each?
– El Tomato
Mar 23 at 7:41
add a comment |
1
expressionValue(with:, context:)really throws? What's its declaration? Seems to be developer.apple.com/documentation/foundation/nsexpression/… there is no "throws", so no reason to do a try.
– Larme
Mar 23 at 7:38
1
Possible duplicate of try, try! & try? what’s the difference, and when to use each?
– El Tomato
Mar 23 at 7:41
1
1
expressionValue(with:, context:) really throws? What's its declaration? Seems to be developer.apple.com/documentation/foundation/nsexpression/… there is no "throws", so no reason to do a try.– Larme
Mar 23 at 7:38
expressionValue(with:, context:) really throws? What's its declaration? Seems to be developer.apple.com/documentation/foundation/nsexpression/… there is no "throws", so no reason to do a try.– Larme
Mar 23 at 7:38
1
1
Possible duplicate of try, try! & try? what’s the difference, and when to use each?
– El Tomato
Mar 23 at 7:41
Possible duplicate of try, try! & try? what’s the difference, and when to use each?
– El Tomato
Mar 23 at 7:41
add a comment |
1 Answer
1
active
oldest
votes
As error explains, there isn't any method which would throw. If you're using optional binding, you just need to use as? Double since you don't know if return type is Double and you need to downcast it
if let result = finalformular.expression.expressionValue(with: nil, context: nil) as? Double
text = String(result)
else
text = "Error"
answered Mar 23 at 7:53
Robert DreslerRobert Dresler
8,3652727
add a comment |
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1 Answer
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1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
As error explains, there isn't any method which would throw. If you're using optional binding, you just need to use as? Double since you don't know if return type is Double and you need to downcast it
if let result = finalformular.expression.expressionValue(with: nil, context: nil) as? Double
text = String(result)
else
text = "Error"
answered Mar 23 at 7:53
Robert DreslerRobert Dresler
8,3652727
add a comment |
As error explains, there isn't any method which would throw. If you're using optional binding, you just need to use as? Double since you don't know if return type is Double and you need to downcast it
if let result = finalformular.expression.expressionValue(with: nil, context: nil) as? Double
text = String(result)
else
text = "Error"
answered Mar 23 at 7:53
Robert DreslerRobert Dresler
8,3652727
add a comment |
As error explains, there isn't any method which would throw. If you're using optional binding, you just need to use as? Double since you don't know if return type is Double and you need to downcast it
if let result = finalformular.expression.expressionValue(with: nil, context: nil) as? Double
text = String(result)
else
text = "Error"
answered Mar 23 at 7:53
Robert DreslerRobert Dresler
8,3652727
As error explains, there isn't any method which would throw. If you're using optional binding, you just need to use as? Double since you don't know if return type is Double and you need to downcast it
if let result = finalformular.expression.expressionValue(with: nil, context: nil) as? Double
text = String(result)
else
text = "Error"
answered Mar 23 at 7:53
Robert DreslerRobert Dresler
8,3652727
edited Mar 23 at 8:34
answered Mar 23 at 7:53
Robert DreslerRobert Dresler
8,3652727
answered Mar 23 at 7:53
Robert DreslerRobert Dresler
8,3652727
answered Mar 23 at 7:53
Robert DreslerRobert Dresler
8,3652727
8,3652727
add a comment |
add a comment |
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1
expressionValue(with:, context:)really throws? What's its declaration? Seems to be developer.apple.com/documentation/foundation/nsexpression/… there is no "throws", so no reason to do a try.– Larme
Mar 23 at 7:38
1
Possible duplicate of try, try! & try? what’s the difference, and when to use each?
– El Tomato
Mar 23 at 7:41