How can I chomp every line in an array at once?

Question

In the interest of writing cleaner code...

IO.popen("Generate a list of files").readlines.each{ |line|
   chomped_line = line.chomp
   # ...
}

score 25 · Accepted Answer · answered Sep 20 '10 at 10:55

25

IO.popen("Generate a list of files").readlines.map(&:chomp)

answered Sep 20 '10 at 10:55

buru

3,190
25
35

score 4 · Answer 2 · answered Sep 18 '14 at 20:26

4

# Example 1
File.readlines("file.txt").each{|line| line.chomp!}

# Example 2
File.readlines("file.txt").map(&:chomp)

# Example 3
File.open("file.txt", "r"){|file| file.readlines.collect{|line| line.chomp}}

answered Sep 18 '14 at 20:26

Alexandre

141
1
1
5

score 3 · Answer 3 · answered Sep 20 '10 at 14:07

3

IO.read("something").split($/)

$/ is the separator string. IO.read closes the file after reading.

answered Sep 20 '10 at 14:07

steenslag

79,051
16
138
171

1

Just a note that `$/` matches `\n` newlines strictly while chomp handles `\r\n` as well. If you know that you will only ever have `\n` newlines this solution is _much_ faster than the map/chomp option. – Matt Sanders Aug 16 '16 at 23:35

score 1 · Answer 4 · answered Nov 14 '13 at 15:09

I would make it faster and consuming less memory:

use "each_line" rather than "readlines.each". Why read the whole output at once?
use "chomp!" (exclamation mark) to change the string in-place.

Then it is:

IO.popen( "generate_lines").each_line { |line|
    line.chomp!
    do_something_with line
}

How can I chomp every line in an array at once?

4 Answers4