Checking the equality of two slices

Question

How can I check if two slices are equal

User · Answer

This is just example using reflect DeepEqual   that is given in  VictorDeryagin s answer   package main  import        fmt       reflect     func main         a      int  4 5 6      b      int  4 5 6      c      int  4 5 6 7       fmt Println reflect DeepEqual a  b       fmt Println reflect DeepEqual a  c        Result   true false   Try it in Go Playground

User · Answer

You need to loop over each of the elements in the slice and test  Equality for slices is not defined  However  there is a bytes Equal function if you are comparing values of type   byte   func testEq a  b   Type  bool           If one is nil  the other must also be nil      if  a    nil      b    nil             return false              if len a     len b            return false            for i    range a           if a i     b i                return false                      return true

User · Answer

If you have two   byte  compare them using bytes Equal  The Golang documentation says      Equal returns a boolean reporting whether a and b are the same length and contain the same bytes  A nil argument is equivalent to an empty slice    Usage   package main  import        fmt       bytes     func main         a      byte  1 2 3      b      byte  1 2 3      c      byte  1 2 2       fmt Println bytes Equal a  b       fmt Println bytes Equal a  c       This will print  true false

User · Answer

And for now  here is https   github com google go-cmp which     is intended to be a more powerful and safer alternative to reflect DeepEqual for comparing whether two values are semantically equal     package main  import        fmt        github com google go-cmp cmp     func main         a      byte 1  2  3      b      byte 1  2  3       fmt Println cmp Equal a  b      true

User · Answer

In case that you are interested in writing a test  then github com stretchr testify assert is your friend   Import the library at the very beginning of the file   import        github com stretchr testify assert      Then inside the test you do    func TestEquality SomeSlice  t   testing T        a      int 1  2      b      int 2  1      assert Equal t  a  b      The error prompted will be                   Diff                  --- Expected                     Actual                    -1 4  1 4                        int   len 2                       int  1                     int  2                  -  int  2                     int  1  Test            TestEquality SomeSlice

User · Answer

You should use reflect DeepEqual       DeepEqual is a recursive relaxation of Go s    operator       DeepEqual reports whether x and y are    deeply equal     defined as   follows  Two values of identical type are deeply equal if one of the   following cases applies  Values of distinct types are never deeply   equal       Array values are deeply equal when their corresponding elements are   deeply equal       Struct values are deeply equal if their corresponding fields  both   exported and unexported  are deeply equal       Func values are deeply equal if both are nil  otherwise they are not   deeply equal       Interface values are deeply equal if they hold deeply equal concrete   values       Map values are deeply equal if they are the same map object or if they   have the same length and their corresponding keys  matched using Go   equality  map to deeply equal values       Pointer values are deeply equal if they are equal using Go s      operator or if they point to deeply equal values       Slice values are deeply equal when all of the following are true  they   are both nil or both non-nil  they have the same length  and either   they point to the same initial entry of the same underlying array    that is   amp x 0      amp y 0   or their corresponding elements  up to   length  are deeply equal  Note that a non-nil empty slice and a nil   slice  for example    byte   and   byte nil   are not deeply equal       Other values - numbers  bools  strings  and channels - are deeply   equal if they are equal using Go s    operator

[go] Checking the equality of two slices

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