Question 194476 in Flutter Question posted in
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How to update any List<Map<String,dynamic>> in flutter

I am new to Flutter. I am facing some issues while updating a list.

Currently, I have a list with some keys and values as follows:

[
  {filename: aa}, 
  {filename: bb.txt}, 
  {filename: cc.txt}
]

And I want to update the above list by adding one more parameter called isPresent and update it as follows by doing some process on current data:

[
  {filename: aa,
   isPresent: false}, 
  {filename: bb.txt,
   isPresent: true}, 
  {filename: cc.txt,
  isPresent: false}
]

How to do that any idea?

To achieve the above updated list I am using the following code

final List<Map<String, dynamic>> list = [...fetchJsonData['data']];
list.asMap().forEach((key, value) async {
  Directory? directory;
  directory = await getExternalStorageDirectory();
  File file = File("${directory!.path}/${list[key]['filename']}");
  await io.File(file.path).exists();
  bool isExists = io.File(file.path).existsSync();
  print(isExists);
  list[key]['isPresent'] = isExists;
});
fileList = list;
print(fileList);

but does not work with Await I think. Let me know if I am missing something.

Tags:

3

Answers


  1. 0

    You can do this for example

    main() {
  List<Map<String, dynamic>> data = [
    {'filename': 'aa'},
    {'filename': 'bb.txt'},
    {'filename': 'cc.txt'}
  ];

  data[0]['isPresent'] = false;
  data[1]['isPresent'] = true;
  data[2]['isPresent'] = false;

  print(data);
  //[{filename: aa, isPresent: false}, {filename: bb.txt, isPresent: true}, {filename: cc.txt, isPresent: false}]
}
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  2. 0

    can you try below code and check :

    List<Map<String, dynamic>> originalList = [
  {"filename": "aa"},
  {"filename": "bb.txt"},
  {"filename": "cc.txt"}
];

List<Map<String, dynamic>> updatedList = originalList.map((item) {
  String filename = item["filename"];
  bool isPresent = /* Perform your process here based on the filename */;
  
  return {
    "filename": filename,
    "isPresent": isPresent,
  };
}).toList();
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  3. 0

    Sure,

    void updateList() {
  
  List<Map<String, dynamic>> data = [
    {"filename": "aa"},
    {"filename": "bb.txt"},
    {"filename": "cc.txt"}
  ];

  for (var file in data) {
    file["isPresent"] = file["filename"].endsWith(".txt");
  }
  print(data);
}
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