sample of Options that i have:
I have 2 List, the first one is named options:
List<String> _options = [
'Arts & entertainment',
'Biographies & memoirs',
...
];
and the other name _isOptionSelected:
List<bool> _isOptionSelected = [
false,
false,
..
];
im trying to generat a map form those 2 list.
what i have tryed is this:
Map<String, Map<String, dynamic>> _isOptionMap = {
'Arts & entertainment': {
'optionName': 'Arts & entertainment',
'isOptionSelected': false,
},
'Biographies & memoirs': {
'optionName': 'Biographies & memoirs',
'isOptionSelected': false,
},
..
};
and then print it:
for (int i = 0; i < _isChoiceChipSelected.length; i++) {
_isOptionMap[_options[i]]['isOptionSelected'].update(
_options[i],
(value) => _isOptionMap[_options[i]]
['isOptionSelected']);
}
print(_isOptionMap);
Is a logical problem? and what im I doing wong ?
Hello this code creates a map like the one you want.
Be aware that "_options" and "_isOptionSelected" lists must have the same lenght.
void main() {
List<String> _options = [
'Arts & entertainment',
'Biographies & memoirs',
];
List<bool> _isOptionSelected = [
false,
false,
];
Map m = {};
_options.asMap().entries.forEach((entry) {
int idx = entry.key;
String val = entry.value;
Map m1 = {
'optionName': val,
'isOptionSelected': _isOptionSelected[idx]
};
m[val] = m1;
});
print( m );
}
Related
I have a list of items containing unique and repeating IDs, I want to sum the prices and display the number of the repeating IDs
class Model{
int id,price,count;
Model(this.id,this.price,this.count);
}
List<Model> list1 = [
Model(1,5000,10),
Model(2,1000,20),
Model(1,5000,5),
Model(2,5000,10),
];
List<Model> list2 = [];
I need the second list to be like this
list2 = [
Model(1,10000,15),
Model(2,6000,30),
];
try this :
void main() {
int sum = 0;
List<Model> list1 = [
Model(1, 5000, 10),
Model(2, 1000, 20),
Model(1, 5000, 5),
Model(2, 5000, 10),
];
List<Model> list2 = modelsWithoutRepeatingIdsButSumOfPricesAndAmount(
list1); // [Model(1,10000,15), Model(2,6000,30),]
}
List<Model> modelsWithoutRepeatingIdsButSumOfPricesAndAmount(
List<Model> modelList) {
Map<int, Model> map = {};
for (int index = 0; index < modelList.length; index += 1) {
Model current = modelList[index];
map[current.id] ??= Model(current.id, 0, 0);
map[current.id]!.price += current.price;
map[current.id]!.count += current.count;
}
return map.values.toList();
}
class Model {
int id, price, count;
Model(this.id, this.price, this.count);
}
Use reduce method to get the sum of a list
var total = [1, 2, 3].reduce((a, b) => a + b);
If you don't want to use reduce method you can also use .fold() there are couple more you can get them by importing dart collections package.
I'm trying to create a copy/clone of a "List<List<Map'>>".
So far I tried:
dataFTY2 = dataFTY.map((element)=>element).toList();
dataFTY2 = json.decode(json.encode(dataFTY));
dataFTY2 = List.from(dataFTY);
Nothing seems to work. Whenever I change the copy "dataFTY2", dataFTY changes as well. I need this to be a completely independent copy. Please help. I cant seem to figure this out, its driving me crazy.
More code added for reference.
List failureDetails = [];
List trackIDs = [];
List dateTime = [];
var dataFTY2 = dataFTY.map((element) => element.map((ele) => Map.from(ele)).toList()).toList();
// get historyData for each one and sort through "F"s and put them into the table in a row?
for (var x in dataFTY2[4]) {
trackIDs.add(x["track_id"]);
dateTime.add(x["datetime"]);
}
List failuresOnly = List.filled(trackIDs.length, {}, growable: true);
for (var i = 0; i < trackIDs.length; i++) {
await fetchTrackIDTestDetails(context, trackIDs[i], dateTime[i], false);
failureDetails.add(MyGlobals().getTestCodeDetailsData());
}
//filter out only "F"s
for (var p = 0; p < failureDetails.length; p++) {
for (var t in failureDetails[p][0]) {
if (t["Status"] == "F") {
//add it to list, if pass do nothing
failuresOnly[p] = t;
}
}
}
//combine with FTY failure data, don't use new screen use old screen and toggle when pressed, add column on right side
//dataFTY2 = MyGlobals().getFTYFailureMoreDetails();
for (var i = 0; i < dataFTY2[4].length; i++) {
dataFTY2[4][i]["TestCode"] = failuresOnly[i]["TestCode"];
dataFTY2[4][i]["Status"] = failuresOnly[i]["Status"];
dataFTY2[4][i]["TestValue"] = failuresOnly[i]["TestValue"];
dataFTY2[4][i]["Lo_Limit"] = failuresOnly[i]["Lo_Limit"];
dataFTY2[4][i]["Up_Limit"] = failuresOnly[i]["Up_Limit"];
dataFTY2[4][i]["ProcTime"] = failuresOnly[i]["ProcTime"];
}
You can use Map.from named constructor to clone the Map like this,
dataFTY2 = dataFTY.map((element) => element.map((ele) => Map.from(ele)).toList()).toList();
I find it more straightforward to use collection-for and the spread (...) operator:
void main() {
var original = [
[
{'foo': 1, 'bar': 2},
{'foo': 3, 'bar': 4},
]
];
// Create a new List...
var copy = [
for (var sublist in original)
// ... where each element is a new List...
[
for (var map in sublist)
// ... where each element of the sublist is a new Map that
// copies all entries from `map`.
{...map},
],
];
original[0][0]['foo'] = -1;
print(original); // Prints: [[{foo: -1, bar: 2}, {foo: 3, bar: 4}]]
print(copy); // Prints: [[{foo: 1, bar: 2}, {foo: 3, bar: 4}]]
}
I have a list like this:
var orderedEvents = [
{
"realTime": "2021-07-28 12:00:02.000" // Flutter dateTime but saved as String
},
{
"realTime": "2021-07-28 12:00:00.000"
},
{
"realTime": "2021-07-28 12:00:01.000"
}
];
And I do:
orderedEvents.sort((a, b) {
final realTimeA = DateTime.parse(a["realTime"]);
final realTimeB = DateTime.parse(b["realTime"]);
return realTimeA.isBefore(realTimeB) ? -1 : 1;
});
But it's not ordered properly obtaining 0, 2 and 1.
First make sure to convert from Strings to DateTimes.
Afterward, simply use the following:
orderedEvents.sort((a,b) {
final realTimeA = DateTime.parse(a["realTime"]);
final realTimeB = DateTime.parse(b["realTime"]);
return realTimeA.compareTo(realTimeB);
});
After a few days it didn't work, I combined the data on the model initially
example: Samsung has a lot of data and I have combined it into an array, I want to ask how to make a search based on the brand name of the model?
#override
Widget build(BuildContext context) {
remoteModelId.clear();
isLoading = true;
final products = Provider.of<List<Brands>>(context);
return Scaffold(
...
body: products != null
? ListView.separated(
itemCount: products.length,
itemBuilder: (context, index) {
var lol = [];
var idModel = [];
var sublist = [].join();
var countList =[];
//var allList =[];
//var subLol = lol.indexOf(lol);
for(var ok in products){
lol.add(ok.brandName);
idModel.add(ok.ids);
countList.add(lol);
if(lol.contains(lol)){
sublist.compareTo(lol[index]);
break;
}
}
distinctIds = lol.toSet().toList();
hasilakhir = Set.of(distinctIds).toList();
newDataList = List.from(distinctIds);
templist.add(hasilakhir);
final myMap = Map();
lol.forEach((element) {
if(!myMap.containsKey(element)){
myMap[element] = 1;
return false;
}else{
myMap[element] += 1;
return false;
}
});
//newDataList = newDataList.map((brand)=>brand.toLowerCase()).toList();
return ListTile(
title: Text(hasilakhir[index]),
Thanks
I am not sure what you need, but here is some example code:
// Get products with a specific brandName
print(
'Number of Samsung=${products.where((p) => p.brandName == 'Samsung').length}');
// Count products by brandName - like your code
final map = Map();
products.forEach((product) {
if (!map.containsKey(product.brandName)) {
map[product.brandName] = 1;
} else {
map[product.brandName] += 1;
}
});
print('map=$map');
// Group products by brandName, with the count and list of ids
final map2 = Map();
products.forEach((product) {
if (!map2.containsKey(product.brandName)) {
map2[product.brandName] = {
'count': 1,
'ids': [product.ids]
};
} else {
var current = map2[product.brandName];
current['count']++;
current['ids'].add(product.ids);
}
});
print('map2=$map2');
The output with my test data is:
Number of Samsung=3
map={Samsung: 3, Apple: 3}
map2={Samsung: {count: 3, ids: [S1, S2, S3]}, Apple: {count: 3, ids: [iPhone1, iPhone2, iPhone3]}}
I do not know if it is helpful, but I have annotated some of your code below:
// Get list of distinct brandNames
var distinctIds = lol.toSet().toList();
// Get list of distinct brandNames - same as distinctIds
var hasilakhir = Set.of(distinctIds).toList();
// Copy list distinctIds
var newDataList = List.from(distinctIds);
List templist = [];
// Make a list with one element which is the list of brandNames
templist.add(hasilakhir);
I have a service which returns a list of dates, which the user can opt for a future payment.
In the UI, there are three drop down boxes, one each for year, month and date.
Now when the user selects a particular year, then the months shown in the next drop down should only contain months corresponding to that particular selected year and similarly when the month is selected only the corresponding dates to that particular selected month should be shown.
The service response is something like below :
[
{
"availableDate":"03/13/2020"
},
{
"availableDate":"04/14/2020"
},
{
"availableDate":"01/15/2020"
},
{
"availableDate":"01/16/2020"
},
{
"availableDate":"02/17/2020"
},
{
"availableDate":"02/18/2020"
},
{
"availableDate":"02/22/2021"
}
]
I was able to split out the dates,months and years and when I tried to change values using onChange, didn't get the desired result. Could some one please help me with the logic or maybe give me a link to get started?
I have found out a solution.
First initialize the variables :
List _serviceData = [];
List _yearList = [];
List _monthList = [];
List _dateList = [];
List<SchedulerYear> _yearData = new List<SchedulerYear>();
List<SchedulerMonth> _monthData = new List<SchedulerMonth>();
List<SchedulerDate> _dateData = new List<SchedulerDate>();
var yearData = [];
var monthData = [];
var _loadData, _year, _month, _date;
Models used :
class SchedulerYear {
String year;
String month;
String date;
SchedulerYear({this.year,this.month,this.date});
#override
String toString() {
return '$year $month $date';
}
}
class SchedulerMonth {
String month;
String date;
SchedulerMonth({this.month,this.date});
#override
String toString() {
return '$month $date';
}
}
class SchedulerDate {
String date;
SchedulerDate({this.date});
#override
String toString() {
return '$date';
}
}
And finally the functions :
List<DropdownMenuItem<String>> getMenuItems(List options) {
List<DropdownMenuItem<String>> items = List();
for (String n in options) {
items.add(DropdownMenuItem(value: n, child: Text(n)));
}
return items;
}
_getYears() async {
_serviceData = await serviceHandler.fadfj; // the service response as a List
_yearData = [];
_yearList = [];
_yearItems = [];
for (int i = 0; i < _serviceData.length; i++) {
_loadData = _serviceData[i].toString();
_month = _loadData.split('/')[0];
_date = _loadData.split('/')[1];
_year = _loadData.split('/')[2];
_yearData.add(SchedulerYear(year: _year, month: _month, date: _date));
_yearList.add(_year);
}
_yearList = _yearList.toSet().toList();
_yearItems = getMenuItems(_yearList);
_selectedYear = _yearItems[0].value;
yearData = _yearData;
}
_getMonths(selectedYear) {
_dateItems = [];
_dateItems = getMenuItems(_initialDate);
_selectedDate = _dateItems[0].value;
_yearData = yearData;
_monthData = [];
_monthList = [];
_monthItems = [];
for (int i = 0; i < _yearData.length; i++) {
if (_yearData[i].year == selectedYear) {
_monthData.add(SchedulerMonth(month: _yearData[i].month, date: _yearData[i].date));
_monthList.add(_yearData[i].month);
}
}
monthData = _monthData;
_monthList = _monthList.toSet().toList();
_monthItems = getMenuItems(_monthList);
_selectedMonth = _monthItems[0].value;
}
_getDates(selectedMonth) {
_monthData = monthData;
_dateData = [];
_dateList = [];
_dateItems = [];
for (int i = 0; i < _monthData.length; i++) {
if (_monthData[i].month == selectedMonth) {
_dateData.add(SchedulerDate(date: _monthData[i].date));
_dateList.add(_monthData[i].date);
}
}
_dateList = _dateList.toSet().toList();
_dateItems = getMenuItems(_dateList);
_selectedDate = _dateItems[0].value;
}
_getYears() is called inside init() and the _getMonths(selectedYear) is called onChange of years dropdown button and _getDates(selectedMonth) on the months dropdown button