Comparison in reading lines from file

Question

There are multiple ways to read lines from a file. Here are three:

# 1
File.open("temp.txt", "r") do |f|
  f.each_line { |l| puts l }
end

# 2
File.open("temp.txt", "r").each_line { |l| puts l }.close

# 3
File.readlines("temp.txt").each { |l| puts l }

1. Do those three methods correctly handle the file (ie, close the file successfully afterwards)?
2. Is there a scenario in which one method surpasses the others (ie, the given file is relatively large)? If so, what's the best practice?

Answer 1

您显示的第一种方式即使在发生错误时也将关闭文件，而其他两种则不会。