golang type conversion package

In recent years, Golang (Go language) has been widely used in various fields, especially in back-end development, where its efficiency, concurrency, security and other features are highly favored. In Golang, type conversion involves many aspects, including type conversion functions, type aliases, interface type assertions, etc. Among them, type conversion function is one of the most commonly used type conversion methods. Below we will introduce in detail the related functions of type conversion in Golang.

1. Type conversion function

Type conversion functions are often called type converters. They are used to convert values ​​of one type to another type. The most common type conversion functions in Golang include string(), int(), float32(), float64(), etc. Below we will introduce the use of these conversion functions one by one.

1. string() function

string() function is used to convert other types to string type. The syntax is:

func string(v interface{}) string

The implementation is very simple:

func string(v interface{}) string {
    switch v := v.(type) {
    case string:
        return v
    case int:
        return strconv.Itoa(v)
    case float64:
        return strconv.FormatFloat(v, 'g', -1, 64)
    // ...
    default:
        return fmt.Sprintf("%v", v)
    }
}

In the above code, v is any type. When v itself is already of type string, just return it directly. When v is of type int, use the strconv.Itoa() function to convert it to a string type. Similarly, when v is a float64 type, use the strconv.FormatFloat() function to convert it to a string type. Finally, if v is of another type, it is converted to string type using the fmt.Sprintf() function.

2. int() function

int() function is used to convert other types to int type. The syntax is:

func int(v interface{}) int

The implementation is as follows:

func int(v interface{}) int {
    switch v := v.(type) {
    case string:
        i, err := strconv.Atoi(v)
        if err != nil {
            return 0
        }
        return i
    case int:
        return v
    case float64:
        return int(v)
    // ...
    default:
        return 0
    }
}

In the above code, v is any type. When v is of string type, use the strconv.Atoi() function to convert it to int type and return the converted result. When v is of type int, the value of v is returned directly. When v is of type float64, use the int() function to convert it to type int, and finally return the converted result. When v is of other types, a value of 0 is returned.

3. float32() function

The float32() function is used to convert other types to float32 type. The syntax is:

func float32(v interface{}) float32

The implementation is as follows:

func float32(v interface{}) float32 {
    switch v := v.(type) {
    case string:
        f, err := strconv.ParseFloat(v, 32)
        if err != nil {
            return 0
        }
        return float32(f)
    case float32:
        return v
    case float64:
        return float32(v)
    // ...
    default:
        return 0
    }
}

In the above code, v is any type. When v is of type string, use the strconv.ParseFloat() function to convert it to type float64, and convert it to type float32 before returning it. When v is of float32 type, the value of v is returned directly. When v is of type float64, use the float32() function to convert it to type float32 and return the converted result. When v is of other types, a value of 0 is returned.

4. float64() function

The float64() function is used to convert other types to float64 type. The syntax is:

func float64(v interface{}) float64

The implementation is as follows:

func float64(v interface{}) float64 {
    switch v := v.(type) {
    case string:
        f, err := strconv.ParseFloat(v, 64)
        if err != nil {
            return 0
        }
        return f
    case float32:
        return float64(v)
    case float64:
        return v
    // ...
    default:
        return 0
    }
}

In the above code, v is any type. When v is of type string, use the strconv.ParseFloat() function to convert it to type float64 and return the converted result. When v is of type float32, use the float64() function to convert it to type float64 and return the converted result. When v is of type float64, the value of v is returned directly. When v is of other types, a value of 0 is returned.

2. Type alias

Type alias is another common type conversion method in Golang. It refers to the way a type is defined as another name, for example:

type MyInt int

In the above example, the int type is defined as the MyInt type. This will allow us to use the MyInt type directly for type conversion.

3. Interface type assertion

Interface type assertion is a way to convert interface types to other types. The syntax is:

v.(T)

where v is the interface type variable and T is the target type to be converted. The following is an example:

var v interface{}
v = 42
if i, ok := v.(int); ok {
    fmt.Println(i)
}

In the above code, an empty interface variable v is first defined and assigned a value of 42. Secondly, convert v to int type through interface type assertion, and assign the converted value to i variable. Finally, use the ok variable to determine whether the conversion is successful.

Summary

Type conversion in Golang includes many methods, among which type conversion function is the most commonly used method. We have introduced four commonly used conversion functions. In addition, type aliases and interface type assertions are also commonly used type conversion methods in Golang. Mastering the use of these type conversions will help us better develop Golang.

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