Leading and trailing spaces for each line from textarea - ruby-on-rails

Question

ruby 2.1.3
rails 4.1.7
I want to generate a unordered list from textarea. So I have to preserve all line breaks for each item and remove leading and trailing spaces.
Well, I'm trying to remove all leading and trailing spaces from each line of textarea with no success.
I'm using a regex:
string_from_textarea.gsub(/^[ \t]+|[ \t]+$/, '')
I've tried strip and rstrip rails methods with no luck too (they are working with the same result as regex):
Leading spaces for each line are removed perfectly.
But with trailing spaces only the last space from string is removed. But I wanna for each line.
What am I missing here? What is the deal with textarea and trailing spaces for each line?
UPDATE
Some code example:
I'm using a callback to save formated data.
after_validation: format_ingredients
def format_ingredients
self.ingredients = #ingredients.gsub(/^[ \t]+|[ \t]+$/, "")
end
Form view:
= f.text_area :ingredients, class: 'fieldW-600 striped', rows: '10'

Answer 1

You can use String#strip
' test text with multiple spaces '.strip
#=> "test text with multiple spaces"
To apply this to each line:
str = " test \ntext with multiple \nspaces "
str = str.lines.map(&:strip).join("\n")
"test\ntext with multiple\nspaces"

Answer 2

This isn't a good use for a regexp. Instead use standard String processing methods.
If you have text that contains embedded LF ("\n") line-ends and spaces at the beginning and ends of the lines, then try this:
foo = "
line 1
line 2
line 3
"
foo # => "\n line 1 \n line 2\nline 3\n"
Here's how to clean the lines of leading/trailing white-space and re-add the line-ends:
bar = foo.each_line.map(&:strip).join("\n")
bar # => "\nline 1\nline 2\nline 3"
If you're dealing with CRLF line-ends, as a Windows system would generate text:
foo = "\r\n line 1 \r\n line 2\r\nline 3\r\n"
bar = foo.each_line.map(&:strip).join("\r\n")
bar # => "\r\nline 1\r\nline 2\r\nline 3"
If you're dealing with the potential of having white-space that contains other forms of white-space like non-breaking spaces, then switching to a regexp that uses the POSIX [[:space:]] character set, that contains white-space used in all character sets. I'd do something like:
s.sub(/^[[:space:]]+/, '').sub(/[[:space:]]+$/, '')

Answer 3

I think #sin probably intimated the problem in his/her first comment. Your file was probably produced on a Windows machine that puts a carriage return/life feed pair ("\r\n") at the end of each line other than (presumably) the last, where it just writes \n. (Check line[-2] on any line other than the last.) That would account for the result you are getting:
r = /^[ \t]+|[ \t]+$/
str = " testing 123 \r\n testing again \n"
str.gsub(r, '')
#=> "testing 123 \r\ntesting again\n"
If this theory is correct the fix should be just a slight tweak to your regex:
r = /^[ \t]+|[ \t\r]+$/
str.gsub(r, '')
#=> "testing 123\ntesting again\n"
You might be able to do this with your regex by changing the value of the global variable $/, which is the input record separator, a newline by default. That could be a problem for the end of the last line, however, if that only has a newline.

Answer 4

I think you might be looking for String#lstrip and String#rstrip methods:
str = %Q^this is a line
and so is this
all of the lines have two spaces at the beginning
and also at the end ^`
`> new_string = ""
> ""
str.each_line do |line|
new_string += line.rstrip.lstrip + "\n"
end
> "this is a line\n and so is this \n all of the lines have two spaces at the beginning \n and also at the end "
2.1.2 :034 > puts new_string
this is a line
and so is this
all of the lines have two spaces at the beginning
and also at the end
> new_string
`> "this is a line\nand so is this\nall of the lines have two spaces at the beginning\nand also at the end\n"`