Golang type fast conversion

Type conversion in golang is very common in programming. Type conversion allows us to convert one data type into another data type, so that we can use variables more flexibly. During the type conversion process, special attention needs to be paid when converting between different types. This article will introduce the basic operations and precautions of type conversion in golang.

Basic type conversion

In golang, basic types can be implemented through explicit type conversion. For example, to convert a variable of type int to a variable of type float64, you can use the following code:

var i int = 10
var f float64 = float64(i)

In this example, a float64() type conversion function is used to convert the value of i to type float64.

However, you need to pay attention when performing similar type conversions. If the conversion target is a smaller type, the conversion may cause data precision to be lost or overflowed.

For example, convert float64 to int type. If the value of the source variable is too large or too small, the data may suffer a loss of precision during the conversion process. This problem can be avoided by checking the data range before performing type conversion. For example:

var f float64 = 3.14
var i int64

if f > math.MaxInt64 || f < math.MinInt64 {
    fmt.Println("数据超出范围")
} else {
    i = int64(f)
}

When performing type conversion, we also need to handle situations that cannot be converted. For example, when converting a string to an int type, if the value of the string cannot be converted to an int type, the program will crash.

Type assertion

In golang, type assertion can be used to determine whether an interface type instance or a variable of value, pointer, slice, mapping, etc. type is an interface type. or an instance of a concrete type.

The basic syntax of type assertion is as follows:

value, ok := a.(type)

Among them, a is an interface type variable, instance, value, pointer, slice, mapping and other type variables; type represents a specific type, such as interface{ }, int, float64, etc.

Type assertion will return two values, one is a variable pointer pointing to the interface type value, and the other is a Boolean value. If the type assertion is successful, the returned Boolean value is true, otherwise it returns false. For example:

var a interface{} = 30
value, ok := a.(int)
if ok {
    fmt.Printf("a是int类型，值为%d
", value)
} else {
    fmt.Printf("a不是int类型")
}

In this example, convert the variable a to type int. If the conversion is successful, it will be output: a is of type int and the value is 30.

It should be noted that if the type assertion fails (the variable is not the target type), the program will throw a panic exception.

The difference between type conversion and type assertion

Although type conversion and type assertion are both used to process types, there are still some differences between them.

• Type conversion is to convert a variable of a certain type into a variable of another type by explicitly performing forced type conversion between different types. Type assertion is to determine whether an object belongs to an interface type or entity type.
• Type conversion is an explicit behavior, while type assertion is an implicit behavior.
• Type conversion only applies to primitive types, while type assertions apply to all interface types and entity types.
• Type conversion is a one-time constant, while type assertion needs to be used multiple times

Summary

In golang, type conversion and type assertion are very common operation. Type conversion converts a variable from one data type to another. However, you need to pay attention to problems such as data accuracy loss or overflow that may be caused by conversion. In addition, before performing type conversion, the data range should be checked to avoid problems.

Type assertions can be used to determine whether a variable belongs to an interface type or entity type. Although type conversion and type assertion are both operations for processing types, there are still some differences between them, and the choice needs to be based on the specific scenario.

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