Unescaping string in Ruby on Rails - ruby-on-rails

Google Book Search Give Output Something like this
Introducing Little Simon's new Baby Snoopy line, featuring Charles Schulz'scharacters as babies.
How do i convert this into normal readable string ?
I tried URI.unescape and searched it online , but couldn't find anything. I am a newbie in Ruby on Rails.

Maybe you need to tell Rails that it's HTML safe.....
controller
#str = get_str_from_google_book_search(ie.your.string)
view
<%= #str.html_safe %>

You don't need to escape that string. The following works just fine.
irb(main):001:0> s="Introducing Little Simon's new Baby Snoopy line, featuring Charles Schulz'scharacters as babies."
=> "Introducing Little Simon's new Baby Snoopy line, featuring Charles Schulz'scharacters as babies."
irb(main):002:0> s
=> "Introducing Little Simon's new Baby Snoopy line, featuring Charles Schulz'scharacters as babies."
If you had a character you needed to escape, such as ", you could escape it with a \ as so:
irb(main):008:0> s = "a\"b"
=> "a\"b"
irb(main):009:0> puts s
a"b
=> nil

The string is already HTML, and you are working in Rails, so I'm not sure that you really need to boil it down further. While the HTML numeric character references in your example string do have both ASCII and Unicode equivalents, anything more complicated like <p> will cause trouble.
However, for your example string, there is a way.
You can use an HTML parser to parse the string as a fragment.
require 'nokogiri'
s1 = 'How's life?'
s2 = Nokogiri::HTML.fragment(s1).to_s
puts s2

Related

Replace of forward slash to backslash in ruby from any path

After a lot of research and brainstorm finally i give up for it and need a help to convert the forwardslash to single backslash But I am not able to do.
Here is some steps which i followed but it does n't works
"C:/projects/test/code".gsub('/','\\') => "C:\\projects\\test\\code"
"C:/projects/test/code".gsub('/','\\\\') => "C:\\projects\\test\\code"
"C:/projects/test/code".gsub('/',"\'\\'") => "C:'projects/test/codeprojects'test/codetest'codecode"
The result which i expect to be should like:
=> "C:\projects\test\code"
Any help and suggestions accepted please help
You did it already with this:
"C:/projects/test/code".gsub('\', '\\') # => "C:\\projects\\test\\code"
Likely you are confused by \\ in output. It's normal. Just try to puts this:
puts "C:/projects/test/code".gsub(/\//, '\\') # => C:\projects\test\code
Updated:
\ is used in Ruby (and not only) for multiline string concatenation so when you just type it in irb, for example, it continues reading user's input.
Some notes about irb:
when you execute some command in irb it outputs the result for debugging purposes:
irb> "foo\r\nbar"
=> "foo\r\nba"
This line contains \r\n what means go to the beginning of the new new line. So if you want to see it in human mode just print it and it gives:
irb> puts "foo\r\nbar"
foo
bar
If you want to prevent output you can use semicolon:
irb> s = "foo\r\nbar";
irb* puts s
foo
bar
What you get in your first example is exactly what you need. In IRB/Pry the representation differs, because REPL is intended to support copy-paste, and the string you see is the exact string with single backward slashes, how one would type it inside double quotes. You might also note double quotes around the string in the REPL representation, which do not belong to the string itself either.
Here is another more explicit way to accomplish a task:
result = "C:/projects/test/code".split('/').join('\\')
#⇒ "C:\\projects\\test\\code"
See:
puts result
#⇒ C:\projects\test\code
result.count("\\")
#⇒ 3
As a matter of fact, Windows does indeed understand the path with forward slashes, so you probably don’t need this conversion at all.

Rails: join an array with a new line between each component

I am trying to make an app in Rails 4.
I have this method:
def full_address
[self.first_line, middle_line, last_line, country_name].compact.join("\n")
end
When I try this, it prints a space between components.
I've read several posts on here that say that single quotation marks are the problem (I've also tried those). I also tried:
def full_address
[self.first_line, middle_line, last_line, country_name].compact.join("<br>")
end
When I try this, it prints 'br' between components.
How do I do this? I've seen responses in several other languages that talk about '+' signs being the solution. I've tried them, it doesnt work. I need help in rails please.
I'm trying to use this in my views show page as:
<%= #address.full_address %>
irb(main):004:0> puts ["a", "b", "c", "d"].join("\n")
a
b
c
d
You didn't show that part of the code but I suspect that the problem is that you're trying to put the result string in an HTML page. HTML ignores whitespace and that is why you don't get the newlines. You can try the solution you proposed with the <br> and try to add .html_safe

trying to keep some escape characters.. but not others. ruby rails

I am having trouble formatting my string correctly. I am reading strings from a file and trying to use them as js code.
file_line = blah'blah"blah
string = line.gsub(/'/, "\\\'").gsub(/"/, "\\\"").dump
I want the output to be:
blah\'blah\"blah
But I cant seem to format it right. I have tried a bunch of things.
I'd use a single gsub matching both, ' and ", along with a block to prepend a \:
line = %q{blah'blah"blah}
string = line.gsub(/["']/) { |m| "\\#{m}" }
#=> "blah\\'blah\\\"blah"
puts string
Output:
blah\'blah\"blah
string = "blah'blah\"blah"
puts string.gsub(/'/,"\\\\'").gsub(/"/,'\"') # => blah\'blah\"blah
There's a whole lot of escaping going on here. To be honest I don't really understand the first one, but the second one is simple. I think in the first one we are escaping the backslash we want to add, and then escaping those two backslashes to avoid ruby interpretting them as a reference to the string. Or something. Trying to do a single level of escaping yields this:
puts string.gsub(/'/,"\\'").gsub(/"/,'\"') # => blahblah\"blahblah\"blah

Rails: truncate string after match

Say I've got a string like so:
"This belongs to that then there's this other keyword which does something else."
How would I truncate it so it'd find keyword and truncate keyword which does something else. to give me only:
"This belongs to that then there's this other "
Thanks!
1.9.3p327 > str = "This belongs to that then there's this other keyword which does something else."
=> "This belongs to that then there's this other keyword which does something else."
1.9.3p327 > str.sub(/keyword.*/, '')
=> "This belongs to that then there's this other "
Be careful though as this will also match on "keywordwithnotrailingspace". Look into \b for getting word boundaries...
A simple tool to add to your toolbelt is Rubular. You can test all sorts of awesome Regex right within your browser... Teach a man to fish ... you know the saying. :)
#emm - I think #Philip's answer is correct; however, I would use a combination of both answers and go with keyword[.|\s]*

Stripping the first character of a string

i have
string = "$575.00 "
string.to_f
// => 0.0
string = "575.00 "
string.to_f
// => 575.0
the value coming in is in this format and i need to insert into a database field that is decimal any suggestions
"$575.00 "
We did this so often we wrote an extension to String called cost_to_f:
class String
def cost_to_f
self.delete('$,').to_f
end
end
We store such extensions in config/initializers/extensions/string.rb.
You can then simply call:
"$5,425.55".cost_to_f #=> 5425.55
If you are using this method rarely, the best bet is to simply create a function, since adding functions to core classes is not exactly something I would recommend lightly:
def cost_to_f(string)
string.delete('$,').to_f
end
If you need it in more than one class, you can always put it in a module, then include that module wherever you need it.
One more tidbit. You mentioned that you need to process this string when it is being written to the database. With ActiveRecord, the best way to do this is:
class Item < ActiveRecord::Base
def price=(p)
p = p.cost_to_f if p.is_a?(String)
write_attribute(:price, p)
end
end
EDIT: Updated to use String#delete!
So many answers... i'll try to summarize all that are available now, before give own answer.
1. string.gsub(/[\$,]/, '')
string.gsub!(/^\$/, '')
2. string[1..-1]
3. string.slice(0) # => "ome string"
4. s/^.//
Why (g)sub and regexp Just for deleting a character? String#tr is faster and shorter. String#delete is even better.
Good, fast, simple. Power of reverse indexing.
Hm... looks like it returns "S". Because it is an alias to String#[]
Perl? /me is cheking question tags...
And my advice is:
What if you have not dollar, but yena? Or what if you don't even have anything before numbers?
So i'll prefer:
string[/\d.+/]
This will crop leading non-decimal symbols, that prevent to_f to work well.
P.S.: By the way. It's known, that float is bad practice for storing money amounts.
Use Float or Decimal for Accounting Application Dollar Amount?
You could try something like this.
string = string[1..-1] if string.match(/^\$/)
Or this.
string.gsub!(/^\$/, '')
Remember to put that backslash in your Regexp, it also means "end of string."
you can use regex for that:
s/^.//
As laways, this is PCRE syntax.
In Ruby, you can use the sub() method of the string class to replace the string:
result = string.sub(/^./,"")
This should work.
[EDIT]
Ok, someone asked what's the gsub() is for:
gsub() acts like sub() but with the /g modifier in PCRE (for global replacement):
s/a/b/
in PCRE is
string.sub(/a/, "b")
and
s/a/b/g
is
string.gsub(/a/, "b")
in Ruby
What I'd use (instead of regular expressions) is simply the built-in slice! method in the String class. For example,
s = "Some string"
s.slice!(0) # Deletes and returns the 0th character from the string.
s # => "ome string"
Documentation here.

Resources