In-depth understanding of data type conversion in Go language

In daily programming, data type conversion is an essential operation, and the Golang language also provides a powerful data type conversion mechanism. In this article, we will take an in-depth look at data type conversion in Go language and some common usage scenarios.

1. Basic concepts of type conversion

In Golang, data types are divided into two types: basic types and composite types. Among them, basic types include integers, floating point types, Boolean types, string types, character types, etc.; composite types include arrays, slices, maps, structures, etc. When performing type conversion, we need to convert a value of a certain type into a value of another type. Conversion between basic types is relatively simple, while conversion of composite types requires more processing.

TYPES is one of the built-in types in Golang, which represents the type itself. In Golang, type conversion is to change the value of one type to the value of another type. This can be achieved with a type conversion operator such as T(x), where T represents the target type and x represents the value to be converted.

For example, the syntax for converting a string to an integer is as follows:

s := "123"
i, err := strconv.Atoi(s)

In the above code, the strconv.Atoi() function converts the value s of string type to the value i of integer type . In addition, this function will also check whether the format of s conforms to the integer specification during the conversion process. If it does not comply, an error will be returned. This requires us to handle error messages carefully when performing type conversion operations.

2. Conversion between basic types

1. Conversion between integer types

In Golang, integer types include signed integer types (int, int8, int16, int32, int64) and unsigned integers (uint, uint8, uint16, uint32, uint64). When converting between integers, if the number of bits of the source type is less than or equal to the number of bits of the target type, the conversion can be performed directly. For example, convert a value of type int32 to a value of type int16:

var i int32 = 100
var j int16 = int16(i)

If the number of bits of the source type is greater than the number of bits of the target type, you need to decide how to perform the conversion based on specific business requirements. Typically, we can truncate or modulo the source value to achieve the conversion.

var i int32 = 10000
var j int16 = int16(i % (1 << 16))

2. Conversion between floating point types

When converting between floating point types, you need to consider the accuracy of floating point numbers. Usually, the precision of floating point numbers is lost during the type conversion process, so we need to choose the conversion method reasonably.

For example, convert a float64 type value to a float32 type value:

var f1 float64 = 1.23456
var f2 float32 = float32(f1)

When performing type conversion of floating point numbers, we need to pay attention to the issue of retaining the number of digits and precision. This is important for Engineering applications are of great significance.

3. Conversion between Boolean and string types

In Golang, you can convert a Boolean value to a string type or a string type value Convert to boolean type. When performing this type of conversion, we can directly use the tools provided by the language:

var b bool = true
var s string = strconv.FormatBool(b)
var b2 bool = strconv.ParseBool(s)

ParseBool() function can parse string type values ​​into corresponding Boolean values.

3. Conversion between composite types

1. Conversion between arrays and slices

In Golang, we can convert values ​​of array types Convert to a slice type value, but not the other way around. This is because a slice type is essentially a pointer to an array, so a slice type can be used instead of an array type. When converting between arrays and slices, we can directly use the tools provided by the Go language:

a := [3]int{1, 2, 3}
s := a[:]

In the above code, we convert the array a into a slice type value s. Note that this conversion does not create new data, it just changes the reference to the data.

2. Conversion between mapping and structure

In Golang, we can convert the value of the structure type to the value of the mapping type, but not the other way around. of. This is because a map type is essentially a collection of key-value pairs, while a structure type is an ordered set of data types.

When converting between mapping and structure, we need to pay attention to the correspondence between the elements between the mapping type and the structure type. Normally, we can use the built-in json package in Golang for conversion.

type Person struct {
    Name string `json:"name"`
    Age  int    `json:"age"`
}
p := Person{"Tom", 18}
m, err := json.Marshal(p) // 结构体 => 映射
var p2 Person
err := json.Unmarshal(m, &p2) // 映射 => 结构体

In the above code, we convert a value p of a structure type into a value m of a mapping type, and then convert the value m of this mapping type into a value p2 of another structure type.

4. Summary

In daily programming, we need to frequently perform data type conversion operations, and the Golang language provides a rich type conversion mechanism. When performing type conversion, we need to pay attention to the difference between the source type and the target type, as well as how to deal with the number of bits and precision issues. When converting composite types, we also need to pay attention to the correspondence between elements.

Through an in-depth understanding of the type conversion mechanism, we can use the Golang language for programming more flexibly and handle common data type operations more efficiently.

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