Go Data Types

Go - Data Types

Data types in Go specify the kind of values a variable can hold and the operations that can be performed on those values. Go is a statically-typed language, meaning variable types are known at compile time.

Go’s data types can be broadly categorized as follows:

Category	Description and Examples
Boolean Types	bool: Represents a boolean value, either true or false. Example: var isActive bool = true
Numeric Types	Represent numbers. Subdivided into: - Integer Types: int8, int16, int32, int64, int (signed); uint8, uint16, uint32, uint64, uint (unsigned). byte is an alias for uint8. rune is an alias for int32 (represents a Unicode code point). Example: var age int = 30, var temperature int8 = -5, var unicodeChar rune = 'G' - Floating-Point Types: float32, float64 (IEEE-754 standard). Example: var price float64 = 19.99 - Complex Types: complex64 (float32 real and imaginary parts), complex128 (float64 real and imaginary parts). Example: var c complex128 = 3 + 4i
String Types	string: Represents a sequence of bytes, typically UTF-8 encoded text. Strings are immutable. Example: var name string = "Golang"
Derived/Composite Types	Constructed from basic types or other composite types: - Pointer Types: e.g., *int (a pointer to an integer). Holds a memory address. - Array Types: e.g., [5]int (an array of 5 integers). Fixed-size. - Slice Types: e.g., []int (a slice of integers). Dynamically-sized view of an array. - Structure Types (struct): e.g., type Point struct { X, Y int }. Groups fields. - Function Types: Represents the signature of a function. - Interface Types: Defines a set of method signatures. - Map Types: e.g., map[string]int. Unordered key-value pairs. - Channel Types: e.g., chan int. Used for goroutine communication.

Integer Types Detailed

Go provides architecture-independent integer types with fixed sizes, as well as implementation-dependent int and uint types.

Type	Size	Range (Approximate)
int8	8-bit	-128 to 127
uint8 (byte)	8-bit	0 to 255
int16	16-bit	-32,768 to 32,767
uint16	16-bit	0 to 65,535
int32 (rune)	32-bit	-2.1 billion to 2.1 billion
uint32	32-bit	0 to 4.2 billion
int64	64-bit	-9 quintillion to 9 quintillion
uint64	64-bit	0 to 18 quintillion
int	32 or 64 bits	Depends on system architecture
uint	32 or 64 bits	Depends on system architecture

Floating-Point Types Detailed

Go supports standard IEEE-754 floating-point numbers.

Type	Precision	Description
float32	Approx. 6-9 decimal digits	32-bit floating-point number
float64	Approx. 15-17 decimal digits	64-bit floating-point number (default for literals like 3.14)

Complex Types Detailed

For complex number arithmetic.

Type	Component Type	Description
complex64	float32	Real and imaginary parts are float32
complex128	float64	Real and imaginary parts are float64

Other Special Numeric Aliases:

• byte: Alias for uint8. Commonly used to represent byte data.
• rune: Alias for int32. Represents a Unicode code point, often used when working with characters and strings.

Additionally, uintptr is an unsigned integer type large enough to store the uninterpreted bits of a pointer value. Its use is typically confined to low-level programming with the unsafe package.

Choosing the right data type is important for memory efficiency and program correctness. For example, using int8 for a value that will never exceed 100 saves memory compared to int64.