Go - Data Types

Variables can be of different types like int, float, struct, slice or it can be of the interface.

The general form for declaring a variable uses the keyword var:

Syntax:-

1. var identifier type  

Example

1. var a int  
2. var b bool  
3. var str string  

when a variable is declared with var it automatically initializes it to the zero-value defined for its type. A type defines the set of values and the set of operations that can take place on those values.

GO Simple Data Type Example

1. package main  
2. import "fmt"  
3. func main() {  
4.    var i int  
5.    var f float64  
6.    var b bool  
7.    var s string  
8.    fmt.Printf("%T %T %T %T\n",i,f,b,s) // Prints type of the variable  
9.    fmt.Printf("%v   %v      %v  %q     \n", i, f, b, s) //prints initial value of the variable  
10. }  

Output:

int float64 bool string
0   0           false  ""    

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Go Construct and Data Types

The Go source code is stored in .go file. The name of the file consists of lowercase letters. If the file name has several parts, it should be separated by underscore "_" .

Go file has a name or an identifier which is case sensitive like C.

For example: a, ax123, i etc.

The _ identifier is special. It is called blank identifier. It may be used in variable declarations.

It is like normal identifiers but its value is discarded, so it cannot be used anymore in the code.

It may happen that the variable, type, or function has no name and even enhance flexibility so it is called anonymous.

These are the 25 keywords for Go-code:

break	default	func	interface	select
case	defer	go	map	struct
chan	else	goto	package	switch
const	fallthrough	If	range	type
continue	for	import	return	var

Programs consist of keywords, constants, variables, operators, types and functions.

The following delimiters are used in constructs such as parentheses ( ), brackets [ ] and braces { }.

The following punctuation characters . , ; : and ... are used.

append	bool	byte	cap	close	complex	complex64	complex128	uint16
copy	false	float32	float64	imag	int	int8	int16	uint32
int32	int64	iota	len	make	new	nil	panic	uint64
print	println	real	recover	string	true	uint	uint8	Uintptr