I have a string which is a function call. I want to parse it and obtain the parameters:
"add_location('http://abc.com/page/1/','This is the title, it is long',39.677765,-45.4343,34454,'http://abc.com/images/image_1.jpg')"
It has a total of 6 parameters and is a mixture of urls, integers and decimals. I can't figure out the regex for the split method which I will be using. Please help!
This is what I have come up with - which is wrong.
/('(.*\/[0-9]*)',)|([0-9]*,)/
Treating the string like a CSV might work:
require 'csv'
str = "add_location('http://abc.com/page/1/','This is the title, it is long',39.677765,-45.4343,34454,'http://abc.com/images/image_1.jpg')"
p CSV.parse(str[13..-2], :quote_char => "'").first
# => ["http://abc.com/page/1/", "This is the title, it is long", "39.677765", "-45.4343", "34454", "http://abc.com/images/image_1.jpg"]
Assuming all non-numeric parameters are enclosed in single quotes, as in your example
string.scan( /'.+?'|[-0-9.]+/ )
You really don't want to be parsing things this complex with a reg-ex; it just won't work in the long run. I'm not sure if you just want to parse this one string, or if there are lots of strings in this form which vary in exact contents. If you give a bit more info about your end goal, you might be able to get some more detailed help.
For parsing things this complex in the general case, you really want to perform proper tokenization (i.e. lexical analysis) of the string. In the past with Ruby, I've had good experiences doing this with Citrus. It's a nice gem for parsing complex tokens/languages like you're trying to do. You can find more about it here:
https://github.com/mjijackson/citrus
Related
I am trying to figure out regex/scripting logic to parse something out like this;
RAW DATA
{CLNDSDB=MedGen:OMIM:SNOMED_CT;CLNDSDBID=C0432243:271640:254100000}
Here, the value is;
MedGen = C0432243
OMIM = 271640
SNOMED_CT = 254100000
Result: 271640
I am envisaging a convoluted if-else loop to get the result. Just wanted to know if there any simple way of get the same result. Much appreciate your answers.
Perhaps something like this: (assuming there is always three fields)
(?<=[=:])(?<key>[^:;]+)(?=[:=;](?:[^:;=]+[=;:]){3}(?<val>[^:]+))
The idea is to capture the field values inside a lookahead assertion so as not to be interfering with overlapping substrings.
However, there is probably a cleaner way that uses successive split.
It's difficult to tell from the question whether the input string is two lines or one:
str = 'RAW DATA
{CLNDSDB=MedGen:OMIM:SNOMED_CT;CLNDSDBID=C0432243:271640:254100000}
'
or
str = '{CLNDSDB=MedGen:OMIM:SNOMED_CT;CLNDSDBID=C0432243:271640:254100000}'
but, in either case I'd use a simple pattern:
str = '{CLNDSDB=MedGen:OMIM:SNOMED_CT;CLNDSDBID=C0432243:271640:254100000}'
medgen, omim, snomed_ct = str.match(/(\w+):(\w+):(\w+)}/).captures
medgen # => "C0432243"
omim # => "271640"
snomed_ct # => "254100000"
Here's the pattern at Rubular.
I am envisaging a convoluted if-else loop to get the result.
Well, don't do that. Most programming solutions are surprisingly simple, so start simple. As you learn, your programming toolbox will grow as you become familiar with new ways of doing things, and you'll find certain tools are more useful for certain tasks. Still, always start from "simple", get the basics working, then carefully add to handle the corner cases.
In this case, when using a regular expression, it's important to look for landmarks in the string that you can use to locate your target text. In this case the trailing '}' is usable, so I wrote three simple captures to find \w strings separated by :.
I'm trying to decode the following string:
body = '{type:paragaph|class:red|content:[class:intro|body:This is the introduction paragraph.][body:This is the second paragraph.]}'
body << '{type:image|class:grid|content:[id:1|title:image1][id:2|title:image2][id:3|title:image3]}'
I need the string to split at the pipes but not where a pipe is contained with square brackets, to do this I think I need to perform a lookahead as described here: How to split string by ',' unless ',' is within brackets using Regex?
My attempt(still splits at every pipe):
x = self.body.scan(/\{(.*?)\}/).map {|m| m[0].split(/ *\|(?!\]) */)}
->
[
["type:paragaph", "class:red", "content:[class:intro", "body:This is the introduction paragraph.][body:This is the second paragraph.]"]
["type:image", "class:grid", "content:[id:1", "title:image1][id:2", "title:image2][id:3", "title:image3]"]
]
Expecting:
->
[
["type:paragaph", "class:red", "content:[class:intro|body:This is the introduction paragraph.][body:This is the second paragraph.]"]
["type:image", "class:grid", "content:[id:1|title:image1][id:2|title:image2][id:3|title:image3]"]
]
Does anyone know the regex required here?
Is it possible to match this regex? I can't seem to modify it correctly Regular Expression to match underscores not surrounded by brackets?
I modified the answer here Split string in Ruby, ignoring contents of parentheses? to get:
self.body.scan(/\{(.*?)\}/).map {|m| m[0].split(/\|\s*(?=[^\[\]]*(?:\[|$))/)}
Seems to do the trick. Though I'm sure if there's any shortfalls.
Dealing with nested structures that have identical syntax is going to make things difficult for you.
You could try a recursive descent parser (a quick Google turned up https://github.com/Ragmaanir/grammy - not sure if any good)
Personally, I'd go for something really hacky - some gsubs that convert your string into JSON, then parse with a JSON parser :-). That's not particularly easy either, though, but here goes:
require 'json'
b1 = body.gsub(/([^\[\|\]\:\}\{]+)/,'"\1"').gsub(':[',':[{').gsub('][','},{').gsub(']','}]').gsub('}{','},{').gsub('|',',')
JSON.parse('[' + b1 + ']')
It wasn't easy because the string format apparently uses [foo:bar][baz:bam] to represent an array of hashes. If you have a chance to modify the serialised format to make it easier, I would take it.
I modified the answer here Split string in Ruby, ignoring contents of parentheses? to get:
self.body.scan(/\{(.*?)\}/).map {|m| m[0].split(/\|\s*(?=[^\[\]]*(?:\[|$))/)}
Seems to do the trick. If it has any shortfalls please suggest something better.
I have a string of images' URLs and I need to convert it into an array.
http://rubular.com/r/E2a5v2hYnJ
How do I do this?
URI.extract(your_string)
That's all you need if you already have it in a string. I can't remember, but you may have to put require 'uri' in there first. Gotta love that standard library!
Here's the link to the docs URI#extract
Scan returns an array
myarray = mystring.scan(/regex/)
See here on regular-expressions.info
The best answer will depend very much on exactly what input string you expect.
If your test string is accurate then I would not use a regex, do this instead (as suggested by Marnen Laibow-Koser):
mystring.split('?v=3')
If you really don't have constant fluff between your useful strings then regex might be better. Your regex is greedy. This will get you part way:
mystring.scan(/https?:\/\/[\w.-\/]*?\.(jpe?g|gif|png)/)
Note the '?' after the '*' in the part capturing the server and path pieces of the URL, this makes the regex non-greedy.
The problem with this is that if your server name or path contains any of .jpg, .jpeg, .gif or .png then the result will be wrong in that instance.
Figuring out what is best needs more information about your input string. You might for example find it better to pattern match the fluff between your desired URLs.
Use String#split (see the docs for details).
Part of the problem is in rubular you are using https instead of http.. this gets you closer to what you want if the other answers don't work for you:
http://rubular.com/r/cIjmjxIfz5
I'm having a problem getting my RegEx to work with my Ruby script.
Here is what I'm trying to match:
http://my.test.website.com/{GUID}/{GUID}/
Here is the RegEx that I've tested and should be matching the string as shown above:
/([-a-zA-Z0-9#:%_\+.~#?&\/\/=]{2,256}\.[a-z]{2,4}\b(\/[-a-zA-Z0-9#:%_\+.~#?&\/\/=]*)([\/\/[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}\/\/[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}\/\/])*?\/)/
3 capturing groups:
group 1: ([-a-zA-Z0-9#:%_\+.~#?&\/\/=]{2,256}\.[a-z]{2,4}\b(\/[-a-zA-Z0-9#:%_\+.~#?&\/\/=]*)([\/\/[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}\/\/[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}\/\/])*?\/)
group 2: (\/[-a-zA-Z0-9#:%_\+.~#?&\/\/=]*)
group 3: ([\/\/[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}\/\/[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}\/\/])
Ruby is giving me an error when trying to validate a match against this regex:
empty range in char class: (My RegEx goes here) (SyntaxError)
I appreciate any thoughts or suggestions on this.
You could simplify things a bit by using URI to deal parsing the URL, \h in the regex, and scan to pull out the GUIDs:
uri = URI.parse(your_url)
path = uri.path
guids = path.scan(/\h{8}-\h{4}-\h{4}-\h{4}-\h{12}/)
If you need any of the non-path components of the URL the you can easily pull them out of uri.
You might need to tighten things up a bit depending on your data or it might be sufficient to check that guids has two elements.
You have several errors in your RegEx. I am very sleepy now, so I'll just give you a hint instead of a solution:
...[\/\/[0-9a-fA-F]....
the first [ does not belong there. Also, having \/\/ inside [] is unnecessary - you only need each character once inside []. Also,
...[-a-zA-Z0-9#:%_\+.~#?&\/\/=]{2,256}...
is greedy, and includes a period - indeed, includes all chars (AFAICS) that can come after it, effectively swallowing the whole string (when you get rid of other bugs). Consider {2,256}? instead.
In Ruby I have an arbitrary string, and I'd like to convert it to something that is a valid Unix/Linux filename. It doesn't matter what it looks like in its final form, as long as it is visually recognizable as the string it started as. Some possible examples:
"Here's my string!" => "Heres_my_string"
"* is an asterisk, you see" => "is_an_asterisk_you_see"
Is there anything built-in (maybe in the file libraries) that will accomplish this (or close to this)?
By your specifications, you could accomplish this with a regex replacement. This regex will match all characters other than basic letters and digits:
s/[^\w\s_-]+//g
This will remove any extra whitespace in between words, as shown in your examples:
s/(^|\b\s)\s+($|\s?\b)/\\1\\2/g
And lastly, replace the remaining spaces with underscores:
s/\s+/_/g
Here it is in Ruby:
def friendly_filename(filename)
filename.gsub(/[^\w\s_-]+/, '')
.gsub(/(^|\b\s)\s+($|\s?\b)/, '\\1\\2')
.gsub(/\s+/, '_')
end
First, I see that it was asked purely in ruby, and second that it's not the same purpose (*nix filename compatible), but if you are using Rails, there is a method called parameterize that should help.
In rails console:
"Here's my string!".parameterize => "here-s-my-string"
"* is an asterisk, you see".parameterize => "is-an-asterisk-you-see"
I think that parameterize, as being compliant with URL specifications, may work as well with filenames :)
You can see more about here:
http://api.rubyonrails.org/classes/ActiveSupport/Inflector.html#method-i-parameterize
There's also a whole lot of another helpful methods.