英文:
Add Flutter Iterable map result into List Array
问题
我们有这个可迭代对象：
Iterable<void> intoarray = listaMap.interests!.map((f) => f['id']);print(intoarray); <--- 结果：flutter: (1, 3, 4)
我想将结果添加到这个数组中：
List<int?> arrayValues = [];arrayValues.add(intoarray 中的元素结果)
我应该对其进行整数解析吗？如何将这些结果放入数组中？一次一个还是一次性全部放入？
英文:
We have this iterable:
Iterable<void> intoarray = listaMap.interests!.map((f) => f['id']);print(intoarray); <--- result: flutter: (1, 3, 4)
And I want add the result into this array:
List<int?> arrayValues = [];arrayValues.add(intoarray result elements)
Should I parse to int for this? How can I put this results int Array? One by One or everything at once?
答案1
得分: 0
这是你问题的一个可能解决方案。void main(){final List<Map<String, dynamic>> listaMap = [{"id":1,},{"id":2,},{"id":3,}];// 你的代码//Iterable<void> intoArray = listaMap.map((f) => f['id']);//print(intoArray);//解决方案// // 如果id总是int// List<int> arrayValues = listaMap.map((f) => f['id'] as int).toList();// // 如果id可为空// List<int?> arrayValues = listaMap.map((f) => f['id'] as int?).toList();// 如果id是String// List<int?> arrayValues = listaMap.map((f) => int.tryParse(f['id'])).toList();// print(arrayValues);// 如果id是动态的List<int?> arrayValues = listaMap.map((f) {final id = f['id'];if (id is int){return id;}else if (id is String){return int.tryParse(id);}return null;}).toList();print(arrayValues);}
英文:
Heres a posible solution for your question.
void main(){final List<Map<String, dynamic>> listaMap = [{"id":1,},{"id":2,},{"id":3,}];// Your code//Iterable<void> intoArray = listaMap.map((f) => f['id']);//print(intoArray);//Solution// // if id is always int// List<int> arrayValues = listaMap.map((f) => f['id'] as int).toList();// // if id is nullable// List<int?> arrayValues = listaMap.map((f) => f['id'] as int?).toList();// if id is String// List<int?> arrayValues = listaMap.map((f) => int.tryParse(f['id'])).toList();// print(arrayValues);// if id is dynamicList<int?> arrayValues = listaMap.map((f) {final id = f['id'];if (id is int){return id;}else if (id is String){return int.tryParse(id);}return null;}).toList();print(arrayValues);}
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