Flutter map string dynamic example
Flutter map string dynamic example

Hi Guys, Welcome to Proto Coders Point, In this Article we will learn about map in dart programming language.

Dart Map

In Dart or any other programming language, A Map Object is a key-value pair to store string or any dynamic data.
Here, In dart map, A key & value can be of any datatype, It  means that we can store any data type because a map in dart language is a dynamic collection of data/information.

In Flutter Dart, A map can be declared in 2 ways : –

  • Using Map Literals.
  • Using Map Constructor.

Declaring a map using Map Literals

To declare a map in dart you need to enclose the key-value pair in a curly bracket “{}”

Syntax
var identifier = { ‘key1′:’value1’ , ‘key2′:’value2’ , ‘key3′:’value3’,  …….. };

Example

var usrMap = {"name": "Proto Coders Point ", 'Website': 'https://protocoderspoint.com/'}; 
   
print(usrMap);

output

map literal example

To get/print particular key value then you can do it like this print ( usrMap[‘name’] ) this will print the value = Proto Coders Point.

Declartion of Map using Map Construtor

Using map constructor, A Map can be declared in 2 steps:

  • Declare Map using it constructor
  • Initilalize the map

Syntax

var identifier = new Map();

then, to initialize to maps with some key-value

identifier[key] = value

Example

void main() { 
  
var logincred = new Map();
  
  logincred['username']='admin';
  logincred['password']='admin@12334#';
  
  print(logincred);

}

output

map constructor example

Properties of Map in dart

So, to us map you need to import dart.core package

  1. Keys : This will return all the key in map object.
  2. Values : Wiil return all the value in map object.
  3. length : Return the number of key-value pair length/size.
  4. isEmpty : Will return true if Map object is empty.
  5. IsNotEmpty : Will return true if map value is not empty.

Function of Map dart

There are some comman task performed with Map in dart:

  1. addAll() : Used to add all key-value of some other Map Object.
  2. clean() : Remove all data from pair.
  3. remove() : Remove Specific date of key.
  4. foreach : used to iterate and read alll map entires.

addAdd() :  Example

void main() { 
  
 var usrMap = {"name": "Proto Coders Point ", 'Website': 'https://protocoderspoint.com/'}; 
  
  
  var map2 = {'email': 'protocoders.come'};
  
  usrMap.addAll(map2);
  
  print(usrMap);


}

output

map add All

remove() : Example

Removes Specific data of key – values from map data, it accept a key which is  needed to be removed.

void main() { 
  
Map m  = { 'id': 01 ,'name': 'Rajat'};

  print("Before removing : ${m}");
  
  dynamic res = m.remove('name'); // here name is the key.
  
  print("removed data is : ${res}");
  
  
  print("After removing ${m}");

}

output

map remove function

foreach : Example

By using foreach function in Map you can easily iterate and read all the maps entries.

Syntax :  Map.forEach(void f(K key , V value));

void main() { 
  
var userdata = { 'name': 'Proto Coders Point', 'Website': 'https://protocoderspoint.com/'};
  
  userdata.forEach((k,v){
    print('  ${k} ${v}');
  });

}

output

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