fmt API Reference

Go fmt package — formatted I/O with C-style verbs.

By EZ4Code TeamLast updated: 2026-08-01

fmt

Package fmt implements formatted I/O with functions analogous to C's printf and scanf.

fmt.Print(a ...any) (n int, err error)

Print using default formats for each operand. Spaces added between operands when neither is a string.

Returns: (int, error)

fmt.Println(a ...any) (n int, err error)

Print using default formats, with spaces between operands and a newline at the end.

Returns: (int, error)

fmt.Printf(format string, a ...any) (n int, err error)

Print according to a format specifier.

Returns: (int, error)

fmt.Sprintf(format string, a ...any) string

Return a string (instead of printing) according to a format specifier.

Returns: string

fmt.Fprintf(w io.Writer, format string, a ...any) (n int, err error)

Write to w according to a format specifier.

Returns: (int, error)

fmt.Scanf(format string, a ...any) (n int, err error)

Scan text read from standard input, storing successive space-separated values into successive arguments.

Returns: (int, error)

fmt.Errorf(format string, a ...any) error

Return an error that formats according to a format specifier. Wraps with %w.

Returns: error