Table of Contents

• Read a file line by line

Read a file line by line howto

• reader.ReadLine() exclude the end-of-line bytes, such as \n and \r.
• reader.ReadString('\n') will not exclude the end-of-line bytes.
• Using scanner.Scan() followed by scanner.Text() would also be possible.

reader.ReadString('\n') isn't fully equivalent to ReadLine because ReadString is unable to handle the case when the last line of a file does not end with the newline character.

The upshot:

reader.ReadString('\n')

• If you don't mind that the line could be very long (i.e. use a lot of RAM)
• It keeps the \n at the end of the string returned.

reader.ReadLine()

• If you care about limiting RAM consumption
• If you don't mind the extra work of handling the case where the line is greater than the reader's buffer size.
• For reader, the defaultBufSize is 4096 bytes.

scanner.Scan(); scanner.Text()

• It does not handle long lines. (Just returns ErrTooLong)
• For scanner, the MaxScanTokenSize is 64 * 1024 bytes.