CODEWITHSUNDEEP
arraysstringgoslice
harryz
harryz

Reputation: 5260

DeepEqual treats array initialized with back tick differently?

My question is quite simple, I use back tick to initiate a string array, but I found that golang treats this array differently: 

import (
    "fmt"
    "reflect"
)

func main() {
    x := []string{`hello world`, "me"}
    y := []string{"hello", "world", "me"}
    fmt.Println(x)
    fmt.Println(y)
    fmt.Println(reflect.DeepEqual(x, y))
}

The output is:

[hello world me]
[hello world me]
false

This makes me confused: should I make sure all string arrays are initiated in the same way?

Upvotes: 0

Views: 50

Answers (1)

icza
icza

Reputation: 417592

Those are slices, not arrays, and your first slice has 2 elements, and the second has 3 elements, so how could they be equal?

Try printing them like this:

fmt.Printf("%d %q\n", len(x), x)
fmt.Printf("%d %q\n", len(y), y)

Output:

2 ["hello world" "me"]
3 ["hello" "world" "me"]

fmt.Prinln() will print all values of the passed slice, printing a space between elements. And first element of x is a string which equals to the first 2 elements of y joined with a space, that's why you see equal printed content for the slices.

When you use the same 3 strings to initialize your first slice with backticks, they will be equal:

x = []string{`hello`, `world`, "me"}
y = []string{"hello", "world", "me"}
fmt.Printf("%d %q\n", len(x), x)
fmt.Printf("%d %q\n", len(y), y)
fmt.Println(reflect.DeepEqual(x, y))

Output:

3 ["hello" "world" "me"]
3 ["hello" "world" "me"]
true

Try these on the Go Playground.

Upvotes: 5

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