Parse CSV different patterns

Question

The regular expression I am looking for have to be able to deal with different patterns.

Those are the 3 different patterns.

"10.1234/altetric55,Awesome Steel Chair,1011-2513"
"\"Sporer, Kihn and Turner\",2885-6503"
"Bartell-Collins,1167-8230"

I will have to pass this regular expression to a ruby split method.

line.split(/regular_expression/)

The idea is to split the test when there is a comma except (like in the second expression) if the comma is part of the text

thanks

See Regex to pick commas outside of quotes. It should solve your issue. — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Nov 2, 2015 at 21:09
Please show your desired output for each of the three strings. — Cary Swoveland
– Cary Swoveland, Commented Nov 2, 2015 at 21:17
What is wrong with CSV parser? See this IDEONE demo or this one. — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Nov 2, 2015 at 21:33
@stribizhev the expected output is ["10.1234/altetric55", "Awesome Steel Chair", "1011-2513] ["Sporer, Kihn and Turner", "2885-6503"] ["Bartell-Collins", "1167-8230"] — Gerard Morera
– Gerard Morera, Commented Nov 2, 2015 at 21:34
Using Ruby's built-in CSV class is my recommendation. It's designed to handle the sort of comma-separated-values you show, including those with embedded commas inside quotes. Don't try to do it with a regex, instead rely on the pre-written, well-tested code. — the Tin Man
– the Tin Man, Commented Nov 2, 2015 at 21:57

Casimir et Hippolyte · Accepted Answer · 2015-11-02 22:04:39Z

2

In this case, don't try to split on each commas that is not enclosed between quotes. Try to find all that is not a comma or content between quotes with this pattern:

"10.1234/altetric55,Awesome Steel Chair,1011-2513".scan(/[^,"]*(?:"[^"\\]*(?:\\.[^"\\]*)*"[^,"]*)*/)

or to avoid empty items:

"10.1234/altetric55,Awesome Steel Chair,1011-2513".scan(/[^,"]+(?:"[^"\\]*(?:\\.[^"\\]*)*"[^,"]*)*|(?:"[^"\\]*(?:\\.[^"\\]*)*")+/)

But you can avoid these complex questions using the CSV class:

require 'csv'
CSV.parse("\"Sporer, Kihn and Turner\",2885-6503")
=> [["Sporer, Kihn and Turner", "2885-6503"]]

edited Nov 2, 2015 at 22:04

answered Nov 2, 2015 at 21:07

Casimir et Hippolyte

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10 Comments

Wiktor Stribiżew Over a year ago

Did you reopen the question? Why?

Casimir et Hippolyte Over a year ago

@stribizhev: Yes I do, because all solutions in the answers of the linked question are ,(?=stupid pattern to know if I am not between quotes until the end of the string) (that stops to work if the string is a bit long).

Wiktor Stribiżew Over a year ago

You have answered almost the same question a day or two ago, why not link to YOUR answer? The questions like this are annoying, there must be a good duplicate original.

Gerard Morera Over a year ago

@CasimiretHippolyte

("10.1234/altetric55,Awesome Steel Chair,1011-2513").split(/[^,"]*(?:"[^"\\]*(?:\\.[^"\\]*)*"[^,"]*)*/ => /[^,"]*(?:"[^"\\]*(?:\\.[^"\\]*)*"[^,"]*)*/  pry(#<FileProcessor::Csv>)>  => ["", ",", ","]

Do I miss something?

Wiktor Stribiżew Over a year ago

Using CSV parser is my suggestion.

|

Cary Swoveland · Accepted Answer · 2015-11-03 03:31:22Z

0

Here's another way, using recursion:

def split_it(str)
  outside_quotes = true
  pos = str.size.times.find do |i|
    case str[i]
    when '"'
      outside_quotes = !outside_quotes
      false
    when ','
      outside_quotes
    else false
    end
  end
  ret = pos ? [str[0,pos], *split_it(str[pos+1..-1])] : [str]
end

["10.1234/altetric55,Awesome Steel Chair,1011-2513",
"\"Sporer, Kihn and Turner\",2885-6503\",,,3\"",
"Bartell-Collins,1167-8230"].map { |s| split_it(s) }
  #=> [["10.1234/altetric55", "Awesome Steel Chair", "1011-2513"],
  #    ["\"Sporer, Kihn and Turner\"", "2885-6503\",,,3\""],
  #    ["Bartell-Collins", "1167-8230"]]

answered Nov 3, 2015 at 3:31

Cary Swoveland

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