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samber
Reverse mutating?
method Reverse is mutating the original collection, is this expected?
collection := []int64{1, 2, 3, 4, 5}
fmt.Println(lo.Reverse(collection))
fmt.Println(collection)
output:
[5 4 3 2 1]
[5 4 3 2 1]
@xyluet I guess they know it because almost all methods here mutating the inputs
func Reverse[T any](collection []T) []T {
length := len(collection)
half := length / 2
for i := 0; i < half; i = i + 1 {
j := length - 1 - i
collection[i], collection[j] = collection[j], collection[i]
}
return collection
}
@xyluet I've found out this lib www.github.com/thoas/go-funk, not sure if it is much better, but at least "reverse" func isn't mutate an input array)
Good catch @xyluet !
I doubt that's expected.
I had a quick look and it looks like only Shuffle and Reverse have this issue.
I had the same problem. And I think it will be more apparent if the Reverse method has no returned value. When it returns a slice, I will believe this is a new slice instead of the original one.
Many libraries have used the following method to convert String to []byte. If the method modifies the original data, panic will occur.
func StringToBytes(s string) []byte {
return unsafe.Slice(unsafe.StringData(s), len(s))
}
Just like this kind of code, panic will appear：lo.Shuffle(StringToBytes("xxx"))
