Here is an example of variable:
names := []interface{}{"first", "second"}
How can it be initialized dynamically, from an array of strings?
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10That's not an array, it's a slice.newacct– newacct2014-01-07 01:46:49 +00:00Commented Jan 7, 2014 at 1:46
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5 Answers
strs := []string{"first", "second"}
names := make([]interface{}, len(strs))
for i, s := range strs {
names[i] = s
}
Would be the simplest
2 Comments
Kir
Thanks! BTW, I found another way without
make: ``` names := []interface{}{} string_names := []string{"first", "second"} for _, v := range string_names { names = append(names, v) } ```
val
Absolutely. Be aware however that
[]interface{}{} initializes the array with zero length, and the length is grown (possibly involving copies) when calling append. This is usually not a problem, if your arrays are not ridiculously large. If they are, make initializes it with full length and never copies it (as the size is known from the start).append initializes slices, if needed, so this method works:
var names []interface{}
names = append(names, "first")
names = append(names, "second")
And here is a variation of the same thing, passing more arguments to append:
var names []interface{}
names = append(names, "first", "second")
This one-liner also works:
names := append(make([]interface{}, 0), "first", "second")
For Go 1.18 or later, this is also possible:
names := append([]any{}, "first", "second")
Yet another option is to first convert the slice of strings to be added to a slice of interface{} or any.
Comments
You can use interface{} array to build it.
values := make([]interface{}, 0)
values = append(values, 1, 2, 3, nil, 4, "ok")
Then check the type when using the value.
for _, v := range values {
if v == nil {
fmt.Println("it is a nil")
} else {
switch v.(type) {
case int:
fmt.Println("it is a int")
case string:
fmt.Println("it is a string")
default:
fmt.Println("i don't know it")
}
}
}
