8 Ways to Use Colon in Go

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In Go, compared to other languages like Python, the use of a colon (:) is limited. Here are the common use cases of a colon in Go:

1. Declaration and Assignment:

A colon is used for short variable declaration and assignment.

x := 42 // short variable declaration and assignment

2. Type Assertion:

A colon is used for type assertion to assert the type of an interface value.

value, ok := myInterface.(int) // Type assertion

3. Map Literal:

A colon is used in map literals to separate keys and values.

myMap := map[string]int{"a": 1, "b": 2}

4. Struct Field Initialization:

A colon is used to initialize struct fields in composite literals.

type Point struct {
    X int
    Y int
}
p := Point{X: 1, Y: 2}

5. Case statements in switch:

The colon is used for case statements in a switch block.

switch value {
case 1:
    // Code block
default:
    // Code block
}

6. Label Statements:

The colon is used for label statements.

Loop:
for i := 0; i < 3; i++ {
    // Code block
    break Loop
}

7. Struct Tag:

The colon is used for struct tags, which provide metadata for struct fields.

type Person struct {
    Name string `json:"name"`
    Age  int    `json:"age"`
}

These are some common uses of colons in Go. Unlike some other languages, Go does not heavily use colons for control flow or other purposes. The usage of colons is relatively simple and consistent in different contexts.

Reference: https://www.jdon.com/70671.html

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