Master Go language whitespace identifiers and improve code quality

The blank identifier (_) represents an identifier that does not assign a value and is used to skip variables or return values ​​that do not need to be processed. It can be used to ignore function return values, iterate over the keys in a collection and ignore values, or as a placeholder. Advantages include improved code readability, avoidance of unnecessary allocations, and reduced likelihood of errors.

Master the Go language whitespace identifier and improve code quality

The whitespace identifier is an identifier that does not assign any value, and is underlined in the Go language (_)express. Whitespace identifiers are often used to ignore variables or return values ​​that are not needed or do not want to be processed. It can significantly improve the quality and readability of your code.

When to use whitespace identifiers

You can use whitespace identifiers in the following situations:

• When you need to ignore the return of a function call value time. For example:

  _, err := os.Open("file.txt")
  if err != nil {
    // 处理错误
  }

• When you need to iterate over the keys in a collection and ignore the values. For example:

  for key, _ := range map[string]int{
    "a": 1,
    "b": 2,
  } {
    // 只处理 key
  }

• When you need a variable as a placeholder but don't care about its value. For example:

  for i := 0; i < 10; i++ {
    _, _ = fmt.Println(i)
  }

Practical case

Let us illustrate the use of blank identifiers through a specific scenario:

Suppose there is a function, using Used to read a file and return the file name and the contents of the file. If we are only interested in the file name, we can use a blank identifier to ignore the file content:

func readFile(filename string) (string, string) {
    data, err := ioutil.ReadFile(filename)
    if err != nil {
        return "", ""
    }
    return filename, string(data)
}

func main() {
    filename, _ := readFile("file.txt")
    fmt.Println(filename)
}

Advantages

Using a blank identifier has the following advantages:

• Improve Code readability: By eliminating unnecessary variables, whitespace identifiers make code cleaner and easier to understand.
• Avoid unnecessary allocations: When omitting a variable, use whitespace identifiers to avoid unnecessary allocation of space in memory.
• Reduce the possibility of errors: You can reduce the possibility of errors by using whitespace identifiers to explicitly ignore variables.

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