Assigning Values

Getting Help
1

hi!.. I wanted to know the difference in the ways of assignign values to a variable

a := 42
and
var a = 42

1 Like
2

a := 42 mean create new variable named a and assign value 42. a = 42 assign value 42 to an existing variable named a. also look here to understand variable declarations.

3

Yes, those ways are equivalent.
a :=42 is a short form for var a = 42.

1 Like
4

nope. first form always create a new variable.the second form assume that the variable already exist and assign a new value. the second form won’t work without explicit declaration (with := or var).

5

There is a var in the second form. They are equivalent.

One difference between them is that the short form declaration is valid in a couple of places where the long form is not; for example

if foo, err := somefunc(); err != nil {
  // ...
}

cannot be written as

if var foo, err = somefunc(); err != nil {
  // ...
}

Of course,

var foo, err = somefunc()
if err != nil {
  // ...
}

is valid but different (the scope of foo and err is larger).

Also, the short form allows redeclaring variables, as long something new is introduced. That is,

foo := 42
foo, bar := 43, 44

is valid, while

foo := 42
var foo, bar = 43, 44

is not.

1 Like
7

Try this:
https://play.golang.org/p/0tj0JVPO0v

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8

the second form won’t work without explicit declaration (with := or var).

mean that only var a = 42 is the same with a := 42. just a = 42 is not the same with a := 42.

9

Nobody said it was. :wink:

1 Like
10

i guess you’re right, i missed var… :slight_smile:

1 Like
11

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