如何在 Ruby 中打印行号 [英] How to print a line number in Ruby

问题描述

我试图通过一个文件来检查每一行以什么空格开头.我们想使用空格作为开始或制表符.如果一行以空格开头，另一行以制表符开头，我想通知用户空格不一致.还有一个例子，我想打印一行以空格开头和一行以制表符开头.我坚持获取行号部分.我试过 file.gets 来获得第一个空格，但它对我不起作用(所以我没有在下面的代码中包含它).帮助我如何打印行号.

I'm trying to go through a file to check every line with what white space it starts. we want to use space as a start or a tab. If one line starts with space and another line with tab I want to inform the user that the white spaces are not consistent. And an example I want to print one line that starts with space and one line that starts with tab. And Im stuck at the getting the line number part. I tried file.gets to get the first white space but it isnt working for me(so I didnt include it in my code below). Help how do I print the line number.

tabs = spaces = false

file = File.read("file_name")
file.each do |line|

  line =~ /^\t/ and tabs = true
  line =~ /^ / and spaces = true    

  if spaces and tabs
    puts  "The white spaces at the beginning of each line are not consistent.\n"
    break
  end
end

推荐答案

基于@zajn 的回答:

Based on @zajn's answer:

file = File.open("filename.txt")
file.each do |line|
  puts "#{file.lineno}: #{line}"
end

或者你可以使用'each with index':

Or you could use 'each with index':

File.open("another_file.txt").each_with_index do |line,i|
  puts "#{i}: #{line}"
end

看起来不那么神奇.

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