如何使用可变数量的项目转换[] string？

Question

I'm trying to parse log strings, where fields are glued with "|" char. All logs suppose to have 20 fields, but some logs have less. I don't want to discard them, but rather fill Log{} with whatever info was there in the log string.

type Log struct {
     Field1  string
     Field2  uint64
     Field3  string
     // ...
     Field20 string
}

Knowing that it's not possible to check if index exists within a slice, this looks suboptimal:

log := Log{}
c := len(fields)

if c > 0 {
    log.Field1 = fields[0]
}

if c > 1 {
    log.Field2, _ = strconv.ParseUint(fields[1], 0, 64)
}

if c > 3 {
    log.Field3 = fields[2]
}

//...

Any better ways doing this?

Thanks

Answer 1

One possibility would be to simply ensure that you always have 20 elements in your slice. Assuming you're populating fields with strings.Split, for example:

fields := make([]string, 20)
copy(fields, strings.Split(input, ","))

// Now `fields` has 20 elements, the first N of which are populated
// by your input, the remainder of which are empty strings (""), so
// you can easily set your struct fields now.

log := Log{
    Field1:  fields[0],
    Field2:  fields[1],
    // ...
    Field20: fields[19],
}