Resolving "Cannot assign []byte to z (type string) in multiple assignment" Error

When attempting to iterate through files in a folder and read their contents, you might encounter the error: "cannot assign []byte to z (type string) in multiple assignment." Let's examine the code and the reason behind this error.

In the provided code snippet, the ReadFile() function is used to read the content of a file and returns two values: a slice of bytes ([]byte) containing the file content and an error, if any. The code tries to assign both values to the same variable z, which is of type string. However, this assignment is invalid because you cannot assign a []byte value to a string variable in a multiple assignment.

To resolve this issue, you need to separate the assignment of the two values returned by ReadFile():

buf, err := ioutil.ReadFile(z)
if err != nil {
        log.Fatal(err)
}

Here, buf is of type []byte, and err is of type error, so the assignment is valid. Once you have read the file content, you can convert it to a string if necessary:

z = string(buf)

Alternatively, you can work directly with buf, which represents the raw bytes of the file content, without converting it to a string. This can improve performance and avoid potential conversion issues.