Shulou(Shulou.com)06/02 Report--

Editor to share with you how to use the core interface of the io package in the Go language, I believe most people do not know much about it, so share this article for your reference. I hope you will learn a lot after reading this article. Let's learn about it together.

Reader

The io.Reader interface defines a Read method that is used to read data into a byte array:

Input parameter: byte array p, which reads the data into p

Return value: the number of bytes read this time, and the error err encountered

Type Reader interface {Read (p [] byte) (n int, err error)}

Detailed explanation of method function

Method is written to the byte array p, which reads at most len (p) bytes at a time because p has a size

Method returns the number of bytes of data read n (0 0). You should process the data before considering whether err is nil. Because as pointed out in the previous point, if you encounter error after reading n > 0 bytes, you will return both n > 0 and erratically retrievnil, so you need to process the data before considering err.

Attention should be paid to the implementation and call of the method

If you want to implement this method, it is not recommended to return both len 0 and err=nil unless len (p) = 0

If you call this method and return nail0 and err=nil, you can assume that nothing has happened and cannot be considered as reading to the end of the file (end-of-file).

After implementing this method, be sure not to hold the byte array p (keep the address for other use)

Writer

The io.Writer interface defines a Write method for writing data to a file.

Input parameter: byte array p, which writes the data in p to the file

Return value: number of bytes successfully written and completed, and error err encountered

Type Writer interface {Write (p [] byte) (n int, err error)}

Detailed explanation of method function

This method writes the data in p to a file

Method returns the number of bytes successfully written n (0)

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