Introduction - If you have any usage issues, please Google them yourself
A self-read text file data function, you can read the entire document, read the first N lines, M reads the first line to the first N lines, M reads the first line to the penultimate N line, read the first M sub- (can also be the last, the penultimate meeting M) of the line str string start (or end) of the data, and so on. I hope everyone can help!