File I/O
Learn to implement and utilize the io.Reader and io.Writer interfaces for file input and output in Go. Understand buffered and unbuffered I/O using the bufio package and avoid deprecated ioutil usage. This lesson provides practical coding examples that demonstrate reading from and writing to files, helping you master Go's core file I/O capabilities.
We shall now discuss file I/O in Go, which includes the use of the io.Reader and io.Writer interfaces, buffered and unbuffered I/O, as well as the bufio package.
Note: The
io/ioutilpackage is deprecated in Go version 1.16. Existing Go code that uses the functionality ofio/ioutilwill continue to work, but it is better to stop using that package.
The io.Reader and io.Writer interfaces
This lesson presents the definitions of the popular io.Reader and io.Writer interfaces because these two interfaces are the basis of file I/O in Go—the former allows us to read from a file whereas the latter allows us to write to a file.
Definition of the io.Reader interface
The definition of the io.Reader interface is the following:
This definition, which should be revisited when we want one of our data types to satisfy the io.Reader interface, tells us the following:
The
Readerinterface requires the implementation of a single methodThe parameter of
Read()is a byte sliceThe return values of
Read()are an integer and an error ...