Delete elements by name from JSON?

Question

I am trying to drop elements from JSON. Here is my code:

String test = '[{
                 "type":"new",
                 "color":"red", 
                 "items": ["aa","bb", "cc"]
                }]';
var myJson = jsonDecode(test);
var result = myJson.where((a)=> a != 'items');
print(result);

It does not work. I need to drop items and get: [{"type":"new","color":"red"}]

Eriks Klotins · Accepted Answer · 2019-08-19T10:12:42.130

0

In the JSON, test array contains one object item with a property items. Thus, filtering is not caching it. To remove items, you need to map over items and remove the items key from each.

UPDATED:

var result = myJson.map((a)=> {a.remove('items'); return a;} );

edited Aug 19 '19 at 10:12

answered Aug 19 '19 at 07:55

Eriks Klotins

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It should maybe also be added that the JSON is actually a list containing a Map. – julemand101 Aug 19 '19 at 07:59
@Eriks I am not sure about proper answer. Maybe it was small misunderstanding. I updated example to show what I need. Your current code print `([aa, bb, cc])` – Dmitry Bubnenkov Aug 19 '19 at 08:01
@Eriks, that should be `m..remove`, not `m.remove`. Please add mention why. – Dmitry Bubnenkov Aug 19 '19 at 08:52
@Eriks, but `myJson.map( (m) => m..remove('items') );` works too Could you explain difference between both approach? – Dmitry Bubnenkov Aug 19 '19 at 10:30
Look at https://stackoverflow.com/questions/49447736/list-use-of-double-dot-in-dart two dots allow chaining of methods. In this case . and .. should be equivalent – Eriks Klotins Aug 19 '19 at 10:49

Delete elements by name from JSON?

1 Answers1