Flutter how to link arrays by ids - flutter

Question

I have data like this
var sendlocal = [
{
"firstName": "tree",
"lastName": "tree",
"relativeEmail": "tree#gmail.com",
"relativeType": 0,
"subid": 1,
"subRelatives": [
{
"firstName": "julia2",
"lastName": "Michle",
"relativeEmail": "test#hotmail.com3",
"relativeType": 2,
"subid": 2,
"subRelatives": [
{
"firstName": "john",
"lastName": "bravo",
"relativeEmail": "johny#gmail.com",
"relativeType": 1,
"subRelatives": [],
"subid": 3,
},
{
"firstName": "simith",
"lastName": "bravo",
"relativeEmail": "johny#gmail.com",
"relativeType": 1,
"subRelatives": [],
"subid": 4,
},
],
},
{
"firstName": "julia3",
"lastName": "Michle",
"relativeEmail": "test3#hotmail.com",
"relativeType": 2,
"subRelatives": [],
"subid": 5,
},
],
},
];
And as per below answer(Thanks) I create a function like this
getIndexFromNestedList(List<dynamic> mapValue) {
if (mapValue != null) {
for (var relation in mapValue) {
print(relation['subid']);
print(relation['relativeEmail']);
if (relation['subRelatives'] != null) {
for (var subRelation in relation['subRelatives']) {
print({relation['subid'], subRelation['subid']});
// graph.addEdge(relation['subid'], subRelation['subid']); //like this
Future.delayed(Duration(milliseconds: 1), () {
getIndexFromNestedList(relation['subRelatives']);
});
}
}
}
}
}
and pass data like this
var check = getIndexFromNestedList(relatives);
And I getting responses like this
flutter: {1, 2}
flutter: {1, 3}
4flutter: {2, null}
What Expected is {2,3} {2,4} and so on if sub relative also have sub relative. But it's showing null don't know why when it's going to sub relatives.

Answer 1

You can use a nested for loop to get those values like the following and resend the loop to the method to get the nested values
getIndexFromNestedList(List<dynamic> mapValue) {
for (var relation in mapValue) {
if (relation['sub'] != null) {
for (var subRelation in relation['sub']) {
print({relation['id'], subRelation['id']});//you can add it directly to the map here.
graph.addEdge(relation['id'], subRelation['id']);//like this
Future.delayed(Duration(milliseconds:1), (){//future is added to finish the first loop then to enter into the inner loops.
getIndexFromNestedList(relation['sub']);
});
}
}
}
}
//OUTPUT
{1, 2}
{1, 6}
{2, 3}
{2, 5}
{2, 3}
{2, 5}
{3, 4}
{3, 4}
{3, 4}
{3, 4}
you can use this method to set the values into the graph
getIndexFromNestedList(reList);
EDIT
for the current structure you can check if the first value is not null before you access its children like the following
getIndexFromNestedList(List<dynamic> mapValue) {
if (mapValue != null) {
for (var relation in mapValue) {
print(relation['subid']);
print(relation['relativeEmail']);
if (relation['subRelatives'] != null) {
for (var subRelation in relation['subRelatives']) {
print({relation['subid'], subRelation['subid']});
// graph.addEdge(relation['subid'], subRelation['subid']); //like this
Future.delayed(Duration(milliseconds: 1), () {
getIndexFromNestedList(relation['subRelatives']);
});
}
}
}
}
}
Edit on 7AUG
In the question again you missed to check if its a null value and if length is greater than 0. also you are passing relatives to the method.. The list name wassendlocal
Here is the updated method with length check too
getIndexFromNestedList(List mapValue) {
if (mapValue != null) {
for (int i = 0; i < mapValue.length; i++) {
for (int j = 0; j < mapValue[i]['subRelatives'].length; j++) {
Map subList = mapValue[i]['subRelatives'][j];
print({mapValue[i]['subid'], subList['subid']});
if (subList['subRelatives'].length > 0) {
Future.delayed(Duration(milliseconds: 10), () {
getIndexFromNestedList(mapValue[i]['subRelatives']);
});
}
}
}
}
}
//Output
flutter: {1, 2}
flutter: {1, 5}
flutter: {2, 3}
flutter: {2, 4}
Tested this multiple times and removed all duplicates too.

Answer 2

I got your answer as per your requirement, maybe this helpful for you
void main(){
var check =getIndexFromList(sendlocal);
}
getIndexFromList(List sendlocal) {
if (sendlocal != null) {
for (var relation in sendlocal) {
print('subid:- ${relation['subid']}');
print('relativeEmail:- ${relation['relativeEmail']}');
if (relation['subRelatives'] != null && relation['subRelatives'].length > 0) {
for (var subRelation in relation['subRelatives']) {
//its your required response
print({relation['subid'], subRelation['subid']});
Future.delayed(Duration(milliseconds: 2), () {
getIndexFromList(relation['subRelatives']);
});
}
}
}
}
}
var sendlocal = [
{
"firstName": "tree",
"lastName": "tree",
"relativeEmail": "tree#gmail.com",
"relativeType": 0,
"subid": 1,
"subRelatives": [
{
"firstName": "julia2",
"lastName": "Michle",
"relativeEmail": "test#hotmail.com3",
"relativeType": 2,
"subid": 2,
"subRelatives": [
{
"firstName": "john",
"lastName": "bravo",
"relativeEmail": "johny#gmail.com",
"relativeType": 1,
"subRelatives": [],
"subid": 3,
},
{
"firstName": "simith",
"lastName": "bravo",
"relativeEmail": "johny#gmail.com",
"relativeType": 1,
"subRelatives": [],
"subid": 4,
},
],
},
{
"firstName": "julia3",
"lastName": "Michle",
"relativeEmail": "test3#hotmail.com",
"relativeType": 2,
"subRelatives": [],
"subid": 5,
},
],
},
];
The response is something like that,
subid:- 1
relativeEmail:- tree#gmail.com
{1, 2}
{1, 5}
subid:- 2
relativeEmail:- test#hotmail.com3
{2, 3}
{2, 4}
subid:- 5
relativeEmail:- test3#hotmail.com
subid:- 2
relativeEmail:- test#hotmail.com3
{2, 3}
{2, 4}
subid:- 5
.............
.............