[Golang Base] local variable initialization: =

a basic usage

Action: = can only be used inside a method, declaring and initializing a new variable

3

But cannot be used to assign values to declared variables, the following procedure compiler will report the error "No new variables on the left side of: ="

var int 0 V: 1

Through the error can be learned that: = operation must have a new variable on the left, then the initialization of multiple variables only need to meet the left at least one new variable can be

ERR: = errors. New ("error1") ret, err:= Test_fun ()

This is legal, because RET is a new variable, which is convenient because the Go method often returns error err, so within the same method

Just declare an ERR variable to

Two: = Trap

Since: = can only be used for local variables, what happens to the following code?

var  out int 1 func Test () {    outof23      }

The scope of the variable out contains test (), but in fact: the operation creates a new local variable out, which you should remember!!!

So a similar scenario:

func test1 () {    V:1    {        V:1    }    }

Will the compiler report "No new variables on the left side of: ="? The compiler does not have an error, so two V is a different variable

If for switch in go can produce a special scoped local variable, you need to be aware of the variable assignment in the IF for switch: =

Conclusion:

1: = local variable on the left side of the same scope, only assignment operation, no newly generated local variable

2: The local variable with the upper scope appears on the left, and a new local variable with the same name is generated and assigned

3: = left non-local variable, generating local variable with the same name as the non-local variable

[Golang Base] local variable initialization: =