String vs. []byte in Go: When to Use Which and Why?

Understanding the Differences Between Strings and []byte in Go

Strings and []byte are distinct types in Go, yet they can be conveniently interconverted.

Key Differences:

• Strings are immutable sequences of Unicode code points, providing support for various character sets.

  • Constant: Expression len(s) remains constant for string literals.
• []byte is a mutable slice of bytes, allowing for modifications to the underlying data.

When to Use Each Type:

The choice between string and []byte depends on specific requirements:

Use Strings:

• When immutability is crucial to avoid unexpected changes.
• When working with Unicode characters, including characters with non-ASCII values.
• When using code that expects strings as parameters (e.g., standard library functions).

Use []byte:

• When byte-level manipulation is necessary, such as reading/writing byte streams.
• When performance is a concern, as strings can incur overhead due to Unicode encoding.
• When code requires a mutable data structure for byte operations.

Conversion:

• To convert a string to []byte, use the []byte(s) constructor.
• To convert a []byte to a string, use the string(b) constructor.

Example:

Consider the following code:

bb := []byte{'h','e','l','l','o',127}
ss := string(bb)
fmt.Println(ss)

Output:

hello

When you convert a []byte to a string, it produces the characters corresponding to the byte values. In this case, the byte 127 is a non-printable character, hence its exclusion from the output.

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