In Ruby, how do I replace the question mark character in a string?

Question

In Ruby, I have:

require 'uri'
foo = "et tu, brutus?"
bar = URI.encode(foo)      # => "et%20tu,%20brutus?"

I'm trying to get bar to equal "et%20tu,%20brutus%3f" ("?" replaced with "%3F") When I try to add this:

bar["?"] = "%3f"

the "?" matches everything, and I get

=> "%3f"

I've tried

bar["\?"]
bar['?']
bar["/[?]"]
bar["/[\?]"]

And a few other things, none of which work.

Answer 1

require 'cgi'并调用CGI.escape

Answer 2

Here's a sample irb session:

irb(main):001:0> x = "geo?"

=> "geo?"

irb(main):002:0> x.sub!("?","a")

=> "geoa"

irb(main):003:0> 

However, sub will only replace the first character. If you want to replace all the question marks in a string, use the gsub method like this:

str.gsub!("?","replacement")

Answer 3

There is only one good way to do this right now in Ruby:

require "addressable/uri"
Addressable::URI.encode_component(
  "et tu, brutus?",
  Addressable::URI::CharacterClasses::PATH
)
# => "et%20tu,%20brutus%3F"

But if you're doing stuff with URIs you should really be using Addressable anyways.

sudo gem install addressable

Answer 4

If you know which characters you accept, you can remove those that don't match.

accepted_chars = 'A-z0-9\s,'
foo = "et tu, brutus?"
bar = foo.gsub(/[^#{accepted_chars}]/, '')

Answer 5

URI.escape accepts the optional parameter to tell which characters you want to escape. It overrides defaults so you'll have to call it twice.

> URI.escape URI.escape("et tu, brutus?"), "?"
=> "et%20tu,%20brutus%3F"