|
Go’s
structs
are typed collections of fields.
They’re useful for grouping data together to form
records.
|
|
|
|
 
package
main
|
|
|
import
"fmt"
|
|
This
person
struct type has
name
and
age
fields.
|
type
person
struct
{
name
string
age
int
}
|
|
newPerson
constructs a new person struct with the given name.
|
func
newPerson
(
name
string
)
*
person
{
|
|
You can safely return a pointer to local variable
as a local variable will survive the scope of the function.
|
p
:=
person
{
name
:
name
}
p
.
age
=
42
return
&
p
}
|
|
|
func
main
()
{
|
|
This syntax creates a new struct.
|
fmt
.
Println
(
person
{
"Bob"
,
20
})
|
|
You can name the fields when initializing a struct.
|
fmt
.
Println
(
person
{
name
:
"Alice"
,
age
:
30
})
|
|
Omitted fields will be zero-valued.
|
fmt
.
Println
(
person
{
name
:
"Fred"
})
|
|
An
&
prefix yields a pointer to the struct.
|
fmt
.
Println
(
&
person
{
name
:
"Ann"
,
age
:
40
})
|
|
It’s idiomatic to encapsulate new struct creation in constructor functions
|
fmt
.
Println
(
newPerson
(
"Jon"
))
|
|
Access struct fields with a dot.
|
s
:=
person
{
name
:
"Sean"
,
age
:
50
}
fmt
.
Println
(
s
.
name
)
|
|
You can also use dots with struct pointers - the
pointers are automatically dereferenced.
|
sp
:=
&
s
fmt
.
Println
(
sp
.
age
)
|
|
Structs are mutable.
|
sp
.
age
=
51
fmt
.
Println
(
sp
.
age
)
|
|
If a struct type is only used for a single value, we don’t
have to give it a name. The value can have an anonymous
struct type. This technique is commonly used for
table-driven tests
.
|
dog
:=
struct
{
name
string
isGood
bool
}{
"Rex"
,
true
,
}
fmt
.
Println
(
dog
)
}
|
