Bool, Equality and Relational Operators
Bool
We already know:
bool is a data type that can have two values: true or false. It is used to store logical values.
Here we have created a variable
of data type bool with value true.
Here we have created a variable of data type bool with value false.
Equality and Relational Operators
In the this section, you will use these operators in conditional expressions to make decisions in the program. For example, you can check whether the user has entered the correct password using the equality operator, or determine if a person has access to a specific resource based on their age (as in the example with user age >= 18 ). In such cases, the result of the comparison becomes a bool value, which helps you make decisions in your program based on conditions.
| Operator | Meaning |
== | equal |
!= | Not equal |
> | Greater than |
< | Less than |
>= | Greater than or equal to |
<= | Less than or equal to |
In this сhapter, we will learn how to store a bool value that will be computed based on whether the condition is true or false.
Examples
main.dart
10 > 2 is a true statement, so we see the result as true.
main.dart
The variables day1 and day8 store the same values, so we get true as a result of the comparison.
Note
There are two equal (
==) signs here because a single equal sign (=) has a completely different meaning. It is used for assignment and cannot (and does not make sense) to be used in if blocks.
Data Type Checking
The following operators do not check the value of the variable. They check the data type of the value.
| Operator | Meaning |
is | true if the value has the specified type |
is! | false if the value has the specified type |
main.dart
We get false because 4.2 is of the double type.
Tasks
Все було зрозуміло?
Зміст курсу
Introduction to Dart
1. First Acquaintance with Dart
2. Variables and Data Types
3. Conditional Statements
4. List and String
Introduction to Dart
Bool, Equality and Relational Operators
Bool
We already know:
bool is a data type that can have two values: true or false. It is used to store logical values.
Here we have created a variable
of data type bool with value true.
Here we have created a variable of data type bool with value false.
Equality and Relational Operators
In the this section, you will use these operators in conditional expressions to make decisions in the program. For example, you can check whether the user has entered the correct password using the equality operator, or determine if a person has access to a specific resource based on their age (as in the example with user age >= 18 ). In such cases, the result of the comparison becomes a bool value, which helps you make decisions in your program based on conditions.
| Operator | Meaning |
== | equal |
!= | Not equal |
> | Greater than |
< | Less than |
>= | Greater than or equal to |
<= | Less than or equal to |
In this сhapter, we will learn how to store a bool value that will be computed based on whether the condition is true or false.
Examples
main.dart
10 > 2 is a true statement, so we see the result as true.
main.dart
The variables day1 and day8 store the same values, so we get true as a result of the comparison.
Note
There are two equal (
==) signs here because a single equal sign (=) has a completely different meaning. It is used for assignment and cannot (and does not make sense) to be used in if blocks.
Data Type Checking
The following operators do not check the value of the variable. They check the data type of the value.
| Operator | Meaning |
is | true if the value has the specified type |
is! | false if the value has the specified type |
main.dart
We get false because 4.2 is of the double type.
Tasks
Все було зрозуміло?
