So let's say I have a string, '$3,444.11'. How do I convert that to a float 3,444.11? I have a form field. The user can insert "3,444.11", "3444.11", or "$3,444.11" or "€3,444.11". What I need is 3,444.11 as a float. Will I have to resort to regex? Or, is there a function already that I'm overlooking?
I don't think there's anything in the standard library that does this for you. Here's a quick one-liner:
'$3,444.11'.gsub(/[^\d\.]/, '').to_f
# => 3444.11
However, you might want to take a look at the money gem for advanced processing of currency strings.
Related
I don't know if it can be called an algorithm but i think its close.
I will be pulling data from an API that will have certain words in the title, eg:
Great Software 2.0 Download Now
Buy Great Software for just $10
Great Software Torrent Download
So, i want to do different things based on the presence of certain words such as Download, Buy etc. For eg, if it has the word 'buy' in it, i would like to extract the word buy and the amount value that is present in the title and show it in another div, so in this case it would be "Buy for $10" or "Buy $10" etc. I can do if/else as well but I don't want to use if else because there could be more such conditions in the future. So what i am thinking about is using the send method. eg:
def buy(string)
'Buy for just' + string.scan(/\$\d+/).first
end
def whichkeyword(title)
send (title.scan(/(download|buy)/i)[0][0]).downcase.to_sym, title
end
whichkeyword('Buy this software for $10 now')
is there a better way to do this? Or is this even a good way to do it? Any help would be appreciated
First of all, use send if and only you are to call private method, use public_send otherwise.
In this particular case metaprogramming is an overkill. It requires too much redundant code, plus it requires the code to be changed for new items. I would go with building a hash like:
#hash = { 'buy' => { text: 'Buy for just %{placeholder}', re: /\$\d+/ } }
This hash might be places somewhere outside of the code, e. g. it might be stored in yml file near the code and loaded in advance. That way you might be able to change a behaviour without modifying the code, that is handy for instance in gem.
As we have a hash defined/loaded, I would call the method:
def format string
key = string[/#{Regexp.union(#hash.keys).source}/i].downcase
puts #hash[key][:text] % { placeholder: string[#hash[key][:re]] }
end
Yielding:
▶ format("Buy this software for $10 now")
#⇒ Buy for just $10
There are many advantages over declaring methods, e. g. now matches might contain spaces, you might easily add/remove matchers etc.
First of all, your algorithm can work, but has some troubles in it, like what if no keyword is applied.
I have two solutions for you:
NLP
If you want to do it much more dynamic, you can use NLP - Natural language Processing. NLP will find main words in you sentence and then you can find the good solution for each.
A good gem for that is Treat that you can use with stanford-core-nlp. After processing the data you can find the verbs and even synonyms in the sentence and figure out what to do.
sentence('Buy this software for $10 now').verbs # ['buy']
Simple Hash
This solution is less dynamic, but much more simple. Like you did with the scan, just use Constant to manage your keywords, and the output from them(I would do it with lambdas). you can also add default to the hash
KEYWORDS = Hash.new('Default Title').merge(
buy: -> { },
download: -> { }
)
KEYWORDS[sentence[/(#{KEYWORDS.keys.join('|')})/i].downcase]
I think this solution is good enough.
The only thing that looks strange is scan(/(download|buy)/i)[0][0].
As for me I don't very much like using [] syntax in Ruby.
I think using scan here is not necessary.
What about
def whichkeyword(title)
title =~ /(download|buy)/i
send $1.downcase.to_sym, title unless $1.nil?
end
UPDATE
def whichkeyword(title)
action = title[/(download|buy)/i]
public_send action.downcase.to_sym, title if action
end
Given a filename, I would like to know if there is a ruby way to obtain the constant name for it.
e.g:
"lib/myproject/connect.rb" => MyProject::Connect
p.s: I know I can create a script for this.
EDIT: consider only the first one at the top.
You may wanna take a look at the implementation of Inflector#camelize in ActiveSupport, see: http://api.rubyonrails.org/classes/ActiveSupport/Inflector.html#method-i-camelize
I have a general idea of how I can do this, but can't pinpoint how exactly to get it done. I am sure it can be done with a regex of some sort. Wondering if anyone here can point me in the right direction.
If I have a string of html such as this
some_html = '<div><b>This is some BOLD text</b></div>'
I want to to divide it into logical pieces, and then put those pieces into an array so I end with a result like this
html_array = ["<div>", "<b>", "This is some BOLD text", "</b>","</div>" ]
Rather than use regex I'd use the nokogiri gem (a gem for parsing html written by Aaron Patterson - contributor to Rails and Ruby). Here's a sample of how to use it:
html_doc = Nokogiri::HTML("<html><body><h1>Mr. Belvedere Fan Club</h1></body></html>")
You can then call html_doc.children to get a nodeset and work your way from there
html_doc.children # returns a nodeset
Use an HTML parser, for instance, Nokogiri. Using SAX you can add tags/elements to the array as events are triggered.
It's not a good idea to try to regex HTML, unless you're planning to treat only a small determined subset of it.
some_html.split(/(<[^>]*>)/).reject{|x| '' == x}
I have a xml file, which i need to modify from my ruby script and save it. xml file looks something like
`
<mtn:messages>
<mtn:message correlation-key="0x" sequence="4">
<mtn:header>
<mtn:protocol-version>0x4</mtn:protocol-version>
<mtn:message-type>0x0F04</mtn:message-type>
<mtn:ttl>4</mtn:ttl>
<mtn:qos-class-of-service>0</mtn:qos-class-of-service>
<mtn:qos-priority>2</mtn:qos-priority>
</mtn:header>
</mtn:message>
</mtn:messages>
</mtn:test-case>
<mtn:test-case title="Train-Consist-Message">
<mtn:messages>
<mtn:message correlation-key="0x" sequence="4">
<mtn:header>
<mtn:protocol-version>0x4</mtn:protocol-version>
<mtn:message-type>0x0F04</mtn:message-type>
<mtn:ttl>4</mtn:ttl>
<mtn:qos-class-of-service>0</mtn:qos-class-of-service>
<mtn:qos-priority>2</mtn:qos-priority>
</mtn:header>
</mtn:message>
</mtn:messages>
</mtn:test-case>`
I need to replace <mtn:ttl>4</mtn:ttl> with <mtn:ttl>some other value</mtn:ttl> which comes under <mtn:test-case title="Train-Consist-Message"> and save it.
I have written below code, but its replacing all occurances of <mtn:ttl>4</mtn:ttl>.
`doc = IO.read(ENV['CadPath1']+ "conf\\cad-mtn-config.xml")
doc.gsub!(pattern, str)
File.open("File path", "w"){|fh| fh.write(doc)}`
Please help me with this. Waiting for your early reply...
String#gsub! modifies the string in-place, replacing all instances with the replacement specified. If you only want to replace the first instance, use String#sub or String.sub!.
The suggestion from Mike about using sub instead of gsub is good. But parsing XML (and HTML) with regular expression is usually frowned upon.
From your question I assume that you locate the to-be-modified element in terms of parent-child relations, not in terms of the source code order (i.e. you will not be able to say: "modify the second occurrence of this pattern"), so inventing a reliable regular expressions may be very, very hard.
You should use a parser library to find the element you want to change. There is a pretty large collection of those. See some of them at http://ruby-toolbox.com/categories/html_parsing.html and pick one, or use a built-in REXML library.
Alternatively, you could use a very simple 'html-scanner' module, which is included in Rails' ActionController (action_controller/vendor/html-scanner.rb), but if you do not use Rails, I am not sure whether extracting it is worth your time.
The exact code will depend on the parser you choose. Usually they have pretty good documentation/tutorials, so I am sure you will be able to handle it.
Still new to Ruby - I apologize in advance if this has been asked.
I am using HTTParty to get data from an API, and it is returning an array of JSON data that I can't quite figure out how to parse.
#<Net::HTTPOK:0x1017fb8c0>
{"ERRORARRAY":[],"DATA":[{"ALERT":1,"LABEL":"hello","WATCHDOG":1},{"LABEL":"goodbye","WATCHDOG":1}
I guess the first question is that I don't really know what I am looking at. When I do response.class I get HTTParty::Response. It appears to be a Hash inside an array? I am not sure. Anyway, I want a way to just grab the "LABEL" for every separate array, so the result would be "hello", "goodbye". How would I go about doing so?
you don't need to parse it per say. what you could do is replace ':' with '=>' and evaluate it.
example: say you have ["one":"a","two":"b"], you could set s to equal that string and do eval s.gsub(/^\[/, '{').gsub(/\]$/, '}').gsub('":', '"=>') will yield a ruby hash (with inspect showing {"one"=>"a", "two"=>"b"})
alternatively, you could do something like this
require 'json'
string_to_parse = "{\"one\":\"a\",\"two\":\"b\"}"
parsed_and_a_hash = JSON.parse(string_to_parse)
parsed_and_a_hash is a hash!
If that's JSON, then your best bet is to install a library that handles the JSON format. There's really no point in reinventing the wheel (although it is fun). Have a look at this article.
If you know that the JSON data will always, always be in exactly the same format, then you might manage something relatively simple without a JSON gem. But I'm not sure that it's worth the hassle.
If you're struggling with the json gem, consider using the Crack gem. It has the added benefit of also parsing xml.
require 'crack'
my_hash_array = Crack::JSON.parse(my_json_string)
my_hash_array = Crack::XML.parse(my_xml_string)