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dart ?? operator

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namesaq answered on May 18, 2022 Popularity 8/10 Helpfulness 2/10

answer dart ?? operator

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dart ?? operator

Comment

??

Called also null operator. This operator returns expression on its left, except if it is null, and if so, it returns right expression:

void main() {
  print(0 ?? 1);  // <- 0
  print(1 ?? null);  // <- 1
  print(null ?? null); // <- null
  print(null ?? null ?? 2); // <- 2
}

Popularity 8/10 Helpfulness 2/10 Language dart

Source: jelenaaa.medium.com

Tags: dart

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Contributed on Aug 16 2022

namesaq

0 Answers Avg Quality 2/10

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operators in dart

Comment

Dart supports the following types of operators.

1.Arithmetic Operators
2.Assignment Operators
3.Relational Operators
4.Type test Operators
5.Logical Operators
6.Bitwise Operator
7.Conditional Operators
8.Casecade notation(..) Operators


1.Dart Arithmetic Operators

Example -
void main(){  
  print("Example of Assignment operators");  
  var n1 = 10;  
  var n2 = 5;  
    
  print("n1+n2 = ${n1+n2}");  
  print("n1-n2 = ${n1-n2}");  
  print("n1*n2 = ${n1*n2}");  
  print("n1/=n2 = ${n1/n2}");   
  print("n1%n2 = ${n1%n2}");     
} 

Output:
Example of Arithmetic operators 
n1+n2 = 15 
n1-n2 = 5 
n1*n2 = 50 
n1/=n2 = 2 
n1%n2 = 0

2. Unary Operators (post and pre)

Example -
void main() {   
   var x = 30;   
   print(x++);                  //The postfix value  
     
var y = 25;  
print(++y);                 //The prefix value,  
         
var z = 10;  
print(--z);                  //The prefix value  
  
var u = 12;                                           
   print(u--);     //The postfix value  
}          
   
Output:
30
26
9
12

3. Assignment Operator

Example -
void main(){  
 print("Example of Assignment operators");  
    
  var n1 = 10;  
  var n2 = 5;  
    
  n1+=n2;  
  print("n1+=n2 = ${n1}");  
    
  n1-=n2;  
  print("n1-=n2 = ${n1}");  
    
  n1*=n2;  
  print("n1*=n2 = ${n1}");  
    
  n1~/=n2;  
  print("n1~/=n2 = ${n1}");  
  n1%=n2;  
  print("n1%=n2 = ${n1}");    
}  

Output:
Example of Assignment operators 
n1+=n2 = 15 
n1-=n2 = 10 
n1*=n2 = 50 
n1~/=n2 = 10 
n1%=n2 = 0 

4. Relational Operator

Example -
void main() {   
var a = 30;  
var b = 20;  
  
print("The example of Relational Operator");  
  
var res = a>b;  
print("a is greater than b: "+res. toString());  // We will learn the toString in next tutorial  
  
var res0 = a<b;  
print("a is less than b: "+res0. toString());  
  
var res1 = a>=b;  
print("a is greater than or equal to b: "+res1. toString());  
  
var res2 = a<=b;  
print("a is less than and equal to b: "+res2. toString());  
  
var res3 = a!= b;  
print("a is not equal to  b: "+res3. toString());  
  
var res4 = a==b;  
print("a is  equal to  b: "+res4. toString());  
}  

Output:
The example of Relational Operator
a is greater than b: true
a is less than b: false
a is greater than or equal to b: true
a is less than and equal to b: false
a is not equal to  b: true
a is  equal to  b: false

5. Type Test Operators

Example:
void main()  
{  
  var num = 10;  
  var name = "JavaTpoint";  
  print(num is int);    
  print(name is! String );  
} 

Output:
true
false

6. Logical Operators

Example:
void main(){  
  bool bool_val1 = true, bool_val2 = false;   
  print("Example of the logical operators");  
    
  var val1 = bool_val1 && bool_val2;  
  print(val1);  
    
  var val2 = bool_val1 || bool_val2;  
  print(val2);  
    
  var val3 = !(bool_val1 || bool_val2);  
  print(val3);   
}  

Output:
false 
true 
false

7. Bitwise Operators

Example -
void main(){  
  print("Example of Bitwise operators");  
    
  var a  = 25;  
  var b = 20;  
  var c = 0;  
    
  // Bitwise AND Operator  
  print("a & b = ${a&b}");  
    
  // Bitwise OR Operator  
  print("a | b = ${a|b}");  
    
  // Bitwise XOR  
  print("a ^ b = ${a^b}");  
    
  // Complement Operator  
  print("~a = ${(~a)}");  
    
  // Binary left shift Operator  
  c = a <<2;  
  print("c<<1= ${c}");  
    
  // Binary right shift Operator  
  c = a >>2;  
  print("c>>1= ${c}");  
}  

Output:
a & b = 16
 a | b = 29
 a ^ b = 13
 ~a = 4294967270
 c<<1= 100
 c>>1= 6

8. Conditional Operators (?:)

Example -
void main() {   
   var x = null;   
   var y = 20;   
   var val = x ?? y;   
   print(val);   
}  

Output:
20

Popularity 9/10 Helpfulness 5/10 Language dart

Source: Grepper

Tags: dart

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Contributed on Nov 10 2022

Ravin Laheri

0 Answers Avg Quality 2/10

or operator in dart

Comment

var a = 10 
var result = ( a>5 || a<10)

Popularity 10/10 Helpfulness 5/10 Language dart

Source: Grepper

Tags: dart

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Contributed on May 24 2022

Vel

0 Answers Avg Quality 2/10

dart operators

Comments(3)

// first individual use

void main() {
  int x = 5;
  int y = 2;
  int z = x + y; // collection operator
  int z = x - y; // extraction operator
  int z = x * y; // impact operator
  int z = x / y; // divide operator
  
}

// seconds if else operators

void main() {
   int x = 2;
   int y = 5;
   if(x == y) {} // equality operator
   if(x < y) {} // less than sign operator
   if(x > y) {} // greater operator
   if(x <= y) {} // less than sign or equality operator
   if(x >= y) {} // greater or equality operator
}

// I guess that's enough for now, good coding <3

Popularity 10/10 Helpfulness 5/10 Language cpp

Source: Grepper

Tags: c++

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Contributed on Aug 15 2022

Marijuana

0 Answers Avg Quality 2/10

dart .. operator

Comment

Cascades (..)

Basically its like then() for objects

To perform a sequence of operations on the same object, use cascades (..). We’ve all seen an expression like this:

// code

myObject.someMethod()

It invokes someMethod() on myObject, and the result of the expression is the return value of someMethod().

Here’s the same expression with a cascade:

// code

myObject..someMethod()

Example

var button = querySelector('#confirm');

button?.text = 'Confirm';

button?.classes.add('important');

button?.onClick.listen((e) => window.alert('Confirmed!'));

button?.scrollIntoView();

With cascade

querySelector('#confirm')

?..text = 'Confirm'

..classes.add('important')

..onClick.listen((e) => window.alert('Confirmed!'))

..scrollIntoView();

Popularity 9/10 Helpfulness 5/10 Language whatever

Source: dart.dev

Tags: dart whatever w

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Contributed on Mar 09 2023

Zion

0 Answers Avg Quality 2/10

dart .. operator

Comment

void main() {
  Person()
    ..name = "John"
    ..age = 30
    ..sex = "Male"
    ..describeMyself();
}

class Person {
  String? name;
  int? age;
  String? sex;

  Person({this.name, this.age, this.sex});

  void describeMyself() {
    print('Hello my name is $name, I am $age years old');
  }
}

Popularity 9/10 Helpfulness 3/10 Language dart

Source: Grepper

Tags: cascade

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Contributed on Jul 08 2022

Wilson Toribio

0 Answers Avg Quality 2/10

dart ?? operator

Comment

String? foo = null;

print(foo ?? " its empty");//output: ' its empty'

foo = "foo";

print(foo ?? " its empty");//output: "foo"

Popularity 9/10 Helpfulness 3/10 Language dart

Source: Grepper

Tags: dart

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Contributed on May 18 2022

Adorable Alpaca

0 Answers Avg Quality 2/10

dart operator ??

Comment

String? foo = null;

print(foo ?? " its empty");//output: ' its empty'

foo = "foo";

print(foo ?? " its empty");//output: "foo"

Popularity 8/10 Helpfulness 2/10 Language dart

Source: Grepper

Tags: dart

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Contributed on Aug 13 2022

Shah Solayman Sinha

0 Answers Avg Quality 2/10

dart is operator

Comment

void main() {
  
  dynamic variable = "hello";
  
  if(variable is String) {
    print("is a String");
  } else {
    print("is not String");
  }
 
  if(variable is int) {
    print("is a int");
  } else {
    print("is not int");
  }
    
}

Popularity 9/10 Helpfulness 1/10 Language dart

Source: Grepper

Tags: dart

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Contributed on Jul 06 2022

Wilson Toribio

0 Answers Avg Quality 2/10

dart ?? operator

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