Go arrays in the language can store the same type of data, but in structures we can define different data types for different items.
A structure is a collection of data that consists of a series of data of thesame type or different types.
A structure represents a record, such as keeping a record of a book in a library, and each book has the following attributes:
Title
Author
Subject
ID
2.36.1. Define the structure #
The structure definition needs to use the type and struct statement. struct statement defines a new data type with one or more members in the structure. type statement sets the name of the structure. The format of the structure is as follows:
type struct_variable_type struct { member definition member definition ... member definition } Once the structure type is defined, it can be used for variable declaration,and the syntax format is as follows:
variable_name := structure_variable_type {value1, value2...valuen} or variable_name := structure_variable_type { key1: value1, key2: value2..., keyn: valuen} Examples are as follows:
2.36.2. Example #
package main import "fmt" type Books struct { title string author string subject string book_id int } func main() { // Create a new structure fmt.Println(Books{"Go language", "www.runoob.com", "Go Language Tutorial", 6495407}) // You can also use the key=>value format fmt.Println(Books{title: "Go language", author: "www.runoob.com", subject: "Go Language Tutorial", book_id: 6495407}) // Ignored field is 0 or empty fmt.Println(Books{title: "Go language", author: "www.runoob.com"}) } The output is as follows:
{Go Language www.runoob.com Go Language Tutorial 6495407} {Go Language www.runoob.com Go Language Tutorial 6495407} {Go Language www.runoob.com 0} 2.36.3. Access structure members #
If you want to access structure members, you need to use a period . operator in the format:
Structure.Member name“ Structure type variables use the The execution result of the above example is: struct keyword definition. An example is as follows:Example #
package main import "fmt" type Books struct { title string author string subject string book_id int } func main() { var Book1 Books /* Declare Book1 as a Book type */ var Book2 Books /* Declare Book2 as a Book type */ /* book 1 describe */ Book1.title = "Go Language" Book1.author = "www.runoob.com" Book1.subject = "Go Language Tutorial" Book1.book_id = 6495407 /* book 2 describe */ Book2.title = "Python Tutorial" Book2.author = "www.runoob.com" Book2.subject = "Python Language Tutorial" Book2.book_id = 6495700 /* Print Book1 information */ fmt.Printf( "Book 1 title : %s\\n", Book1.title) fmt.Printf( "Book 1 author : %s\\n", Book1.author) fmt.Printf( "Book 1 subject : %s\\n", Book1.subject) fmt.Printf( "Book 1 book_id : %d\\n", Book1.book_id) /* Print Book2 information */ fmt.Printf( "Book 2 title : %s\\n", Book2.title) fmt.Printf( "Book 2 author : %s\\n", Book2.author) fmt.Printf( "Book 2 subject : %s\\n", Book2.subject) fmt.Printf( "Book 2 book_id : %d\\n", Book2.book_id) }
Book 1 title : Go Language Book 1 author : www.runoob.com Book 1 subject : Go Language Tutorial Book 1 book_id : 6495407 Book 2 title : Python Tutorial Book 2 author : www.runoob.com Book 2 subject : Python Language Tutorial Book 2 book_id : 6495700
2.36.4. Structure as a function parameter #
You can pass the structure type as an argument to the function like any other data type. And access the structure variables as shown in the above example: The execution result of the above example is:Example #
package main import "fmt" type Books struct { title string author string subject string book_id int } func main() { var Book1 Books /* Declare Book1 as a Book type */ var Book2 Books /* Declare Book2 as a Book type */ /* book 1 describe */ Book1.title = "Go language" Book1.author = "www.runoob.com" Book1.subject = "Go Language Tutorial" Book1.book_id = 6495407 /* book 2 describe */ Book2.title = "Python Tutorial" Book2.author = "www.runoob.com" Book2.subject = "Python Language Tutorial" Book2.book_id = 6495700 /* Print Book1 information */ printBook(Book1) /* Print Book2 information */ printBook(Book2) } func printBook( book Books ) { fmt.Printf( "Book title : %s\\n", book.title) fmt.Printf( "Book author : %s\\n", book.author) fmt.Printf( "Book subject : %s\\n", book.subject) fmt.Printf( "Book book_id : %d\\n", book.book_id) }
Book title : Go Language Book author : www.runoob.com Book subject : Go Language Tutorial Book book_id : 6495407 Book title : Python Tutorial Book author : www.runoob.com Book subject : Python Language Tutorial Book book_id : 6495700
2.36.5. Structure pointer #
You can define pointers to structures that are similar to other pointer variables in the following format:
var struct_pointer *Books The pointer variable defined above can store the address of the structure variable. To view the address of the structure variable, you can set the & symbol is placed in front of the structural variable:
struct_pointer = &Book1 Use structure pointers to access structure members, using the "." operator:
struct_pointer.title Next, let’s rewrite the above example with a structure pointer, as follows: The execution result of the above example is:Example #
package main import "fmt" type Books struct { title string author string subject string book_id int } func main() { var Book1 Books /* Declare Book1 as a Book type */ var Book2 Books /* Declare Book2 as a Book type */ /* book 1 describe */ Book1.title = "Go language" Book1.author = "www.runoob.com" Book1.subject = "Go Language Tutorials" Book1.book_id = 6495407 /* book 2 describe */ Book2.title = "Python Tutorials" Book2.author = "www.runoob.com" Book2.subject = "Python Language Tutorials" Book2.book_id = 6495700 /* Print Book1 information */ printBook(&Book1) /* Print Book2 information */ printBook(&Book2) } func printBook( book *Books ) { fmt.Printf( "Book title : %s\\n", book.title) fmt.Printf( "Book author : %s\\n", book.author) fmt.Printf( "Book subject : %s\\n", book.subject) fmt.Printf( "Book book_id : %d\\n", book.book_id) }
Book title : Go Language Book author : www.runoob.com Book subject : Go Language Tutorial Book book_id : 6495407 Book title : Python Tutorial Book author : www.runoob.com Book subject : Python Language Tutorial Book book_id : 6495700