Golang从文件中读取数据并指示缺少值

Question

I am parsing a csv file which contains integer values, some of them might be missing:

1,2,3
1,2,
1,2,3

In my code I'm populating a struct with the data:

type Line struct {
    One   *int
    Two   *int
    Three *int
}

My current guess to handle missing values would be to use a pointer to an int in order to show whether the value is missing:

// if nil, then no value in file
l := &Line{}
// read and parse...
l.Three = nil

However, using this approach makes assingment to *int cumbersome:

l := &Line{}
// NOT POSSIBLE, NOT COMPILING (cannot use 5 (type int) as type *int in assignment)
l.One = 5
// FEELS WRONG, BUT WORKS
tmpInt := 5
l.One = &tmpInt

How to handle missing integer values?

Answer 1

You could use a function to build your Line{} from a []string, a simple example:

func NewLine(s []string) (l *Line) {
    fmt.Println(len(s))
    if len(s) < 2 {
        return
    }
    l = &Line{}
    if i, err := strconv.Atoi(s[0]); err == nil {
        l.One = &i
    }
    if i, err := strconv.Atoi(s[1]); err == nil {
        l.Two = &i
    }
    if len(s) == 3 {
        if i, err := strconv.Atoi(s[2]); err == nil {
            l.Three = &i
        }

    }
    return
}