Question

使用Ruby的Enumerable#grep方法获取匹配行与行号的最佳方法是什么？（因为我们使用-n或--line-number使用grep命令切换。）

Answer 1

Enumerable＃grep不允许你这样做，至少在默认情况下是这样。相反，我提出了：

text = 'now is the time
for all good men
to come to the aid
of their country'

regex = /aid/

hits = text.lines.with_index(1).inject([]) { |m,i| m << i if (i[0][regex]); m }
hits # => [["to come to the aid\n", 3]]

Answer 2

可能是这样的：

module Enumerable
  def lgrep(pattern)
    map.with_index.select{|e,| e =~ pattern}
  end
end

Answer 3

这不优雅或高效，但为什么不在grepping之前对行进行编号？

Answer 4

你可以像Ruby那样在Ruby 1.8.6中使用它：

require 'enumerator'
class Array
  def grep_with_index(regex)
    self.enum_for(:each_with_index).select {|x,i| x =~ regex}
  end
end
arr = ['Foo', 'Bar', 'Gah']
arr.grep_with_index(/o/) # => [[0, 'Foo']]
arr.grep_with_index(/a/) # => [[1, 'Bar'], [2, 'Gah']]

或者，如果您正在寻找有关在Ruby中编写类似grep的实用程序的技巧。这样的事情应该有效：

def greplines(filename, regex)
  lineno = 0
  File.open(filename) do |file|
    file.each_line do |line|
      puts "#{lineno += 1}: #{line}" if line =~ regex
    end
  end
end

Answer 5

>> lines=["one", "two", "tests"]
=> ["one", "two", "tests"]
>> lines.grep(/test/){|x| puts "#{lines.index(x)+1}, #{x}" }
3, tests

Answer 6

将Tin Man和ghostdog74的答案混为一谈

text = 'now is the time
for all good men
to come to the aid
of their country'

regex = /aid/

text.lines.grep(/aid/){|x| puts "#{text.lines.find_index(x)+1}, #{x}" }
# => 3, to come to the aid

Answer 7

Tin Man给出的解决方案的修改。此代码段将返回一个散列，其中行号作为键，匹配行作为值。这个也适用于ruby 1.8.7。

text = 'now is the time
for all good men
to come to the aid
of their country'

regex = /aid/


hits = text.lines.each_with_index.inject({}) { |m, i| m.merge!({(i[1]+1) => i[0].chomp}) if (i[0][regex]); m}

hits #=> {3=>"to come to the aid"}

Answer 8

将文字放入档案

test.log中

 now is the time
 for all good men
 to come to the aid
 of their country

命令行（替代grep或awk命令）

ruby -ne ' puts $_  if $_=~/to the/' test.log

试试这个

ruby -na -e ' puts $F[2] if $_=~/the/' test.log

同样

ruby -na -e ' puts $_.split[2] if $_=~/the/' test.log

这与awk命令类似。

Answer 9

另一个建议：

lines.find_index{ |l| l=~ regex }。

Ruby grep与行号

9 个答案:

test.log中