Golang function parameter validation and data type conversion

The Go language provides methods for parameter verification and data type conversion to ensure safety and maintainability: Parameter verification: Use assertions to check whether conditions are met, and trigger a panic if they are not met. Custom error types to indicate invalid arguments and return them. Data type conversion: Use the strconv package to explicitly convert strings to other types. Automatically perform implicit type conversions when types are compatible. These techniques help ensure the validity of function parameters and easily convert data types, thereby improving the reliability and maintainability of your code.

Go language function parameter verification and data type conversion

In the Go language, function parameter verification and data type conversion are important for safety and maintainability sexual measures. This tutorial will guide you on how to use built-in tools and custom methods to perform these operations efficiently.

Parameter validation

The Go language does not provide a native parameter validation mechanism, but there are two common alternatives:

• Use assertions: Assertions can be used to check whether a function parameter meets a specific condition and cause a panic if it does not.

func ValidateUser(name string, age int) {
  if name == "" {
    panic("name cannot be empty")
  }
  if age < 0 {
    panic("age cannot be negative")
  }
}

• Custom error types: You can create custom error types and return them to indicate invalid arguments.

type InvalidParameterError struct {
  param string
  msg string
}

func (e *InvalidParameterError) Error() string {
  return fmt.Sprintf("invalid parameter: %s - %s", e.param, e.msg)
}

func ValidateUser(name string, age int) error {
  if name == "" {
    return &InvalidParameterError{param: "name", msg: "cannot be empty"}
  }
  if age < 0 {
    return &InvalidParameterError{param: "age", msg: "cannot be negative"}
  }

  return nil
}

Data type conversion

Go language supports explicit and implicit data type conversion.

• Explicit conversion: Use the strconv package to convert strings to other types.

import "strconv"

func ConvertAgeToInt(age string) (int, error) {
  return strconv.Atoi(age)
}

• Implicit conversion: In some cases, implicit type conversion is automatically performed when the types are compatible.

func AddNumber(a, b int) int {
  // 隐式将 a 转换为 float64
  return a + float64(b)
}

Practical case

Case 1: Validating user input

In a web application, we may need to validate what is received from the form to the user input.

func ValidateUserInput(name string, email string) error {
  if name == "" {
    return &InvalidParameterError{param: "name", msg: "cannot be empty"}
  }

  if _, err := mail.ParseAddress(email); err != nil {
    return &InvalidParameterError{param: "email", msg: "invalid email format"}
  }

  return nil
}

Case 2: Data type conversion

The data retrieved from the database may be a string, but we may need to convert it to other types for processing.

func ConvertDuration(duration string) (time.Duration, error) {
  duration, err := strconv.ParseInt(duration, 10, 64)
  if err != nil {
    return 0, err
  }

  return time.Duration(duration)
}

By using these techniques, you can ensure the validity of function parameters and easily convert data to the required types, thereby improving the reliability and maintainability of your code.

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