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Parse dynamic as int or fallback to a default value

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0

I have a map with dynamic values, one of which can be an int, string or null (i.e. non-existing key).

I want to store this value in an int variable. The parsing I came up with ended up being quite cumbersome:

Map<String, dynamic> map = 'maxposts': null; // or 23 or '42'

// Try to parse an int value or fall back to 0
int maxposts = (map['maxposts'] is int) 
 ? map['maxposts'] 
 : int.tryParse(map['maxposts'] ?? '0') ?? 0;

Is there a nicer way of doing such a "try-fallback" parsing?

dart flutter dynamic-typing

share|improve this question

asked Mar 8 at 8:40

Magnus WMagnus W

4,37553164

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  I don't think there is.
  
  – Günter Zöchbauer
  Mar 8 at 8:43
  

  
  
  
  

add a comment | 

0

I have a map with dynamic values, one of which can be an int, string or null (i.e. non-existing key).

I want to store this value in an int variable. The parsing I came up with ended up being quite cumbersome:

Map<String, dynamic> map = 'maxposts': null; // or 23 or '42'

// Try to parse an int value or fall back to 0
int maxposts = (map['maxposts'] is int) 
 ? map['maxposts'] 
 : int.tryParse(map['maxposts'] ?? '0') ?? 0;

Is there a nicer way of doing such a "try-fallback" parsing?

dart flutter dynamic-typing

share|improve this question

asked Mar 8 at 8:40

Magnus WMagnus W

4,37553164

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  I don't think there is.
  
  – Günter Zöchbauer
  Mar 8 at 8:43
  

  
  
  
  

add a comment | 

I have a map with dynamic values, one of which can be an int, string or null (i.e. non-existing key).

I want to store this value in an int variable. The parsing I came up with ended up being quite cumbersome:

Map<String, dynamic> map = 'maxposts': null; // or 23 or '42'

// Try to parse an int value or fall back to 0
int maxposts = (map['maxposts'] is int) 
 ? map['maxposts'] 
 : int.tryParse(map['maxposts'] ?? '0') ?? 0;

Is there a nicer way of doing such a "try-fallback" parsing?

dart flutter dynamic-typing

share|improve this question

asked Mar 8 at 8:40

Magnus WMagnus W

4,37553164

Map<String, dynamic> map = 'maxposts': null; // or 23 or '42'

// Try to parse an int value or fall back to 0
int maxposts = (map['maxposts'] is int) 
 ? map['maxposts'] 
 : int.tryParse(map['maxposts'] ?? '0') ?? 0;

dart flutter dynamic-typing

dart flutter dynamic-typing

share|improve this question

asked Mar 8 at 8:40

Magnus WMagnus W

4,37553164

share|improve this question

asked Mar 8 at 8:40

Magnus WMagnus W

4,37553164

asked Mar 8 at 8:40

Magnus WMagnus W

4,37553164

asked Mar 8 at 8:40

Magnus WMagnus W

4,37553164

1 Answer
1

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0

You can abstract the operation into a function like

int intOrStringValue(dynamic o) 
 if (o is String) o = int.tryParse(o);
 return o ?? 0;

or

int intOrStringValue(dynamic o) =>
 (o is String ? int.tryParse(o) : o) ?? 0;

It gets more readable when you don't repeat the map['maxposts'] expression throughout the logic.

share|improve this answer

answered Mar 8 at 9:43

lrnlrn

11.3k1527

add a comment | 

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0

You can abstract the operation into a function like

int intOrStringValue(dynamic o) 
 if (o is String) o = int.tryParse(o);
 return o ?? 0;

or

int intOrStringValue(dynamic o) =>
 (o is String ? int.tryParse(o) : o) ?? 0;

It gets more readable when you don't repeat the map['maxposts'] expression throughout the logic.

share|improve this answer

answered Mar 8 at 9:43

lrnlrn

11.3k1527

add a comment | 

0

You can abstract the operation into a function like

int intOrStringValue(dynamic o) 
 if (o is String) o = int.tryParse(o);
 return o ?? 0;

or

int intOrStringValue(dynamic o) =>
 (o is String ? int.tryParse(o) : o) ?? 0;

It gets more readable when you don't repeat the map['maxposts'] expression throughout the logic.

share|improve this answer

answered Mar 8 at 9:43

lrnlrn

11.3k1527

add a comment | 

You can abstract the operation into a function like

int intOrStringValue(dynamic o) 
 if (o is String) o = int.tryParse(o);
 return o ?? 0;

or

int intOrStringValue(dynamic o) =>
 (o is String ? int.tryParse(o) : o) ?? 0;

It gets more readable when you don't repeat the map['maxposts'] expression throughout the logic.

share|improve this answer

answered Mar 8 at 9:43

lrnlrn

11.3k1527

int intOrStringValue(dynamic o) 
 if (o is String) o = int.tryParse(o);
 return o ?? 0;

int intOrStringValue(dynamic o) =>
 (o is String ? int.tryParse(o) : o) ?? 0;

share|improve this answer

answered Mar 8 at 9:43

lrnlrn

11.3k1527

answered Mar 8 at 9:43

lrnlrn

11.3k1527

answered Mar 8 at 9:43

lrnlrn

11.3k1527