I am trying to add a linebreak to a text object in rails.
Using rails 5.0 and postgres 9.4
some_text = "string sentence one"
some_text += #how do i add line break here
some_text = "string sentence two"
I've tried chr(10), '\n', \n, '/\n/' and /\n/
How would I add a line break to some_text?
tl;dr
Below is a loop that I am using in a controller to loop through attributes of an object and try to add a line break to it
#some_text ||= ""
object.attributes.each do |attr_name, attr_value|
#some_text << attr_value.to_s + "\n"
end
When I display the #some_text object in a view, it has no line breaks. If I save the #some_text object into postgres, it still has no line breaks.
It's "\n" (with double quotes):
some_text = "string sentence one"
some_text << "\n"
some_text << "string sentence two"
If you want to output multiline string in irb or der Rails console use puts. Whereas p doesn't work, because it shows control characters instead.
It is worth noting that line break in HTML are usually not displayed in the rendered document. To translate new line characters in strings (\n) into visible HTML line breaks (<br>) there a several options:
Translating the string (string_with_linebreaks.gsub("\n", '<br>')),
use Rails' simple_format text helper or a markdown parser,
place the string into a <pre> block that usually (unless the default css is changed) will preserves both spaces and line breaks or
declare a css rule like white-space: pre-line on the surrounding HTML tag.
Related
Let's say I have a string with the contents
local my_str = [[
line1
line2
line4
]]
I'd like to get the following table:
{"line1","line2","","line4"}
In other words, I'd like the blank line 3 to be included in my result. I've tried the following:
local result = {};
for line in string.gmatch(my_str, "[^\n]+") do
table.insert(result, line);
end
However, this produces a result which will not include the blank line 3.
How can I make sure the blank line is included? Am I just using the wrong regex?
Try this instead:
local result = {};
for line in string.gmatch(my_str .. "\n", "(.-)\n") do
table.insert(result, line);
end
If you don't want the empty fifth element that gives you, then get rid of the blank line at the end of my_str, like this:
local my_str = [[
line1
line2
line4]]
(Note that a newline at the beginning of a long literal is ignored, but a newline at the end is not.)
You can replace the + with *, but that won't work in all Lua versions; LuaJIT will add random empty strings to your result (which isn't even technically wrong).
If your string always includes a newline character at the end of the last line like in your example, you can just do something like "([^\n]*)\n" to prevent random empty strings and the last empty string.
In Lua 5.2+ you can also just use a frontier pattern to check for either a newline or the end of the string: [^\n]*%f[\n\0], but that won't work in LuaJIT either.
If you need to support LuaJIT and don't have the trailing newline in your actual string, then you could just add it manually:
string.gmatch(my_str .. "\n", "([^\n]*)\n")
I am using Smarter CSV to and have encountered a csv that has blank lines. Is there anyway to ignore these? Smarter CSV is taking the blank line as a header and not processing the file correctly. Is there any way I can bastardize the comment_regexp?
mail.attachments.each do | attachment |
filename = attachment.filename
#filedata = attachment.decoded
puts filename
begin
tmp = Tempfile.new(filename)
tmp.write attachment.decoded
tmp.close
puts tmp.path
f = File.open(tmp.path, "r:bom|utf-8")
options = {
:comment_regexp => /^#/
}
data = SmarterCSV.process(f, options)
f.close
puts data
Sample File:
[
output
Let's first construct your file.
str = <<~_
#
# Report
#---------------
Date header1 header2 header3 header4
20200 jdk;df 4543 $8333 4387
20200 jdk 5004 $945876 67
_
fin_name = 'in'
File.write(fin_name, str)
#=> 223
Two problems must be addressed to read this file using the method SmarterCSV::process. The first is that comments--lines beginning with an octothorpe ('#')--and blank lines must be skipped. The second is that the field separator is not a fixed-length string.
The first of these problems can be dealt with by setting the value of process' :comment_regexp option key to a regular expression:
:comment_regexp => /\A#|\A\s*\z/
which reads, "match an octothorpe at the beginning of the string (\A being the beginning-of-string anchor) or (|) match a string containing zero or more whitespace characters (\s being a whitespace character and \z being the end-of-string anchor)".
Unfortunately, SmarterCSV is not capable of dealing with variable-length field separators. It does have an option :col_sep, but it's value must be a string, not a regular expression.
We must therefore pre-process the file before using SmarterCSV, though that is not difficult. While are are at, we may as well remove the dollar signs and use commas for field separators.1
fout_name = 'out.csv'
fout = File.new(fout_name, 'w')
File.foreach(fin_name) do |line|
fout.puts(line.strip.gsub(/\s+\$?/, ',')) unless
line.match?(/\A#|\A\s*\z/)
end
fout.close
Let's look at the file produced.
puts File.read(fout_name)
displays
Date,header1,header2,header3,header4
20200,jdk;df,4543,8333,4387
20200,jdk,5004,945876,67
Now that's what a CSV file should look like! We may now use SmarterCSV on this file with no options specified:
SmarterCSV.process(fout_name)
#=> [{:date=>20200, :header1=>"jdk;df", :header2=>4543,
# :header3=>8333, :header4=>4387},
# {:date=>20200, :header1=>"jdk", :header2=>5004,
# :header3=>945876, :header4=>67}]
1. I used IO::foreach to read the file line-by-line and then write each manipulated line that is neither a comment nor a blank line to the output file. If the file is not huge we could instead gulp it into a string, modify the string and then write the resulting string to the output file: File.write(fout_name, File.read(fin_name).gsub(/^#.*?\n|^[ \t]*\n|^[ \t]+|[ \t]+$|\$/, '').gsub(/[ \t]+/, ',')). The first regular expression reads, "match lines beginning with an octothorpe or lines containing only spaces and tabs or spaces and tabs at the beginning of a line or spaces and tabs at the end of a line or a dollar sign". The second gsub merely converts multiple tabs and spaces to a comma.
File.new(fout_name, 'w')
File.foreach(fin_name) do |line|
fout.puts(line.strip.gsub(/\s+\$?/, ',')) unless
line.match?(/\A#|\A\s*\z/)
end
fout.close
I have JSON strings that may contain \n, \t, which I don't want to save into database. strip_tags helps only with simple strings. I am using gsub(/(\\n)|(\\t)/, "").
I wonder if there is another Rails helper method or a better way to achieve this.
e.g
"[{\"type\":\"checkbox-group\",\"label\":\"\\n\\n\\n\\n\\n\\n\\n\\n\\n\\n\\n\\n\\n\\n\\nFill in\\nthe Gap (Please\\nfill in the blank box with correct wor\",\"name\":\"checkbox-group-1527245153706\",\"values\":[{\"label\":\"Option 1\",\"value\":\"option-1\",\"selected\":true}]},{\"type\":\"text\",\"label\":\"\\n\\t\\t\\n\\t\\n\\t\\n\\t\\t\\n\\t\\t\\t\\n\\t\\t\\t\\t\\n\\t\\t\\t\\t\\t\\n\\t\\t\\t\\t\\t\\t\\n\\t\\t\\t\\t\\t\\t\\t\\n\\t\\t\\t\\t\\t\\t\\t\\tWhat are the unique features of\\ne-commerce, digital markets, and\\ndigital goods? \\n\\t\\t\\t\\t\\t\\t\\t\\n\\t\\t\\t\\t\\t\\t\\n\\t\\t\\t\\t\\t\\n\\t\\t\\t\\t\\n\\t\\t\\t\\n\\t\\t\",\"className\":\"form-control\",\"name\":\"text-1527245426509\",\"subtype\":\"text\"}]"
You can make use of squish or squish!
" Some text \n\n and a tab \t\t with new line \n\n ".squish
#=> "Some text and a tab with new line"
Squish removes all the whitespace chars on both ends and grouping remaining whitespace chars (\n, \t, space) in one space
I think this one may help you,
JSON.parse(string).map{ |a| a['label'] = a['label'].squish; a}
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'
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"
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:]]+$/, '')
I think #sin probably intimated the problem in his/her first comment. Your file was probably produced on a Windows machine that puts a carriage return/life feed pair ("\r\n") at the end of each line other than (presumably) the last, where it just writes \n. (Check line[-2] on any line other than the last.) That would account for the result you are getting:
r = /^[ \t]+|[ \t]+$/
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.
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"`
Data stored in the database is like this:
This is a line
This is another line
How about this line
When I output it to the view, I want to convert that to:
This is a line\n\nThis is another line\n\nHow about this line
with no new lines and the actual \n characters printed out. How can I do that?
> s = "hi\nthere"
> puts s
hi
there
> puts s.gsub(/\n/, "\\n")
hi\nthere
I would personally use gsub if you only want newlines specifically converted. However, if you want to generally inspect the contents of the string, do this:
str = "This is a line\n\nThis is another line\n\nHow about this line"
puts str.inspect[1..-2]
#=> This is a line\n\nThis is another line\n\nHow about this line
The String#inspect method escapes various 'control' characters in your string. It also wraps the string with ", which I've stripped off above. Note that this may produce undesirable results, e.g. the string My name is "Phrogz" will come out as My name is \"Phrogz\".
> s = "line 1\n\nline2"
=> "line 1\n\nline2"
> puts s
line 1
line2
> puts s.gsub("\n", "\\n")
line 1\n\nline2
The key is to escape the single backslash.