CODEWITHSUNDEEP
flutterdart
user13677862
user13677862

Reputation:

How to access single value from this type of List?

I have a List Like this:

final List _subcoll=[
    {'name':'Java','pdfurl':'pdf1','thumbnail':'1'},
    {'name':'Dart','pdfurl':'pd2','thumbnail':'2'},
    {'name':'JavaScript','pdfurl':'pdf3','thumbnail':'3'},
    {'name':'PHP','pdfurl':'pdf4','thumbnail':'4'},
    {'name':'Python','pdfurl':'pdf5','thumbnail':'5'},
  ];

How Can I Access a Single value such as name= java, and pdffile=pdf1?`

Upvotes: 0

Views: 147

Answers (2)

scrimau
scrimau

Reputation: 1385

If you want to access an element of a list by index just use square brackets [ ]:

final e = _subcoll[idx];

Dart will guess the type (at compile-time) here, for non-final variables you can use var.

In your case, an element is probably of type Map<String, String>, you can be explicit and specify it:

final Map<String, String> e = _subcoll[idx];

You can get the index of the first matching item with:

final int i = _subcoll.indexWhere((e)=>e["name"]=="java" && e["pdffile"]="pdf1");

The first matching item with:

final e = _subcoll.firstWhere((e)=>e["name"]=="java" && e["pdffile"]="pdf1");

Or an Iterable with all matching items with:

for(final e in _subcoll.where((e)=>e["name"]=="java" && e["pdffile"]="pdf1"){
    doSmth();
}

Upvotes: 1

Alok
Alok

Reputation: 8978

I don't know whether you have found an answer to that, but here is the solution [more basic precisely] which you want to do in order to get the desired result.

Basically, it is just looping through the array, and then fetching the data like this: array[index][dictionary_key_name]

Dictionary_key is nothing but {} data

// In this case we have keys like 'name', 'pdfurl' and value like 'Java', and 'thumbnail'
// Every key is connected to the value in dictionary or hashmap/hashmap
dictionary = {key: value}

void main(){
  final List _subcoll=[
    {'name':'Java','pdfurl':'pdf1','thumbnail':'1'},
    {'name':'Dart','pdfurl':'pd2','thumbnail':'2'},
    {'name':'JavaScript','pdfurl':'pdf3','thumbnail':'3'},
    {'name':'PHP','pdfurl':'pdf4','thumbnail':'4'},
    {'name':'Python','pdfurl':'pdf5','thumbnail':'5'},
  ];

  /* 
     You can do whatever in the output you want
     My output is to just show you how it is working

    Just focus on how I got the result, _subscoll[index][hashkey]
  */
  for(int i=0; i<_subcoll.length; i++){
    print('name => ${_subcoll[i]['name']}, pdfurl => ${_subcoll[i]['pdfurl']}');
  }
}

OUTPUT

name => Java, pdfurl => pdf1
name => Dart, pdfurl => pd2
name => JavaScript, pdfurl => pdf3
name => PHP, pdfurl => pdf4
name => Python, pdfurl => pdf5

Play around with that more, and let me know if you have any doubts with the result.

Upvotes: 0

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