From: Mark Sparshatt <msparshatt@...>
Date: 2004-07-24T20:22:06+09:00
Subject: Re: The number of lines of a file?

polarpolar wrote:

>Hi, Ruby Fans :
>
>I would like to write a simple program, which can read random line:
>( file.txt has 7 lines )
>
>1:  srand 5269
>2:  f = File.new( "file.txt", "r" )
>3:  print f.readlines[ rand(6) ]
>
>Thus I can get one line in file.txt by random. ( of course easily. )
>Still, the "file.txt" will not only be a 7-lines file, right ? ;)
>How can I get the number of lines of a file ?
>So that I can get one line in file.txt by random
>more flexibly just like:
>
>1:  srand 5269
>2:  f = File.new( "file.txt", "r" )
>3:  print f.readlines[ rand( lines_of_file-1 ) ]
>
>  
>
this way should work

srand 5269
lines = File.readlines("file.txt")
print lines[rand(lines.length)]

it reads the file into an array and then uses the length of the array

HTH

--
Mark Sparshatt