How to split text in Ruby without creating empty strings?

Question

Splitting on whitespace, period, comma or double quotes, and not on single quotes:

str = %Q{this is the.string    to's split,real "ok" nice-like.}
str.split(/\s|\.|,|"/)
=> ["this", "is", "the", "string", "", "", "", "to's", "split", "real", "", "ok", "", "nice-like"]

How to eloquently remove empty strings?

How to eloquently remove strings that are shorter than MIN_LENGTH?

Answer 1

The idea of using split is not right in this case. You should be using scan.

str = %Q{this is the.string    to's split,real "ok" nice-like.}
str.scan(/[\w'-]+/)
# => ["this", "is", "the", "string", "to's", "split", "real", "ok", "nice-like"]

In order to match strings that are MIN_LENGTH or longer, do like this:

MIN_LENGTH = 3
str.scan(/[\w'-]{#{MIN_LENGTH},}/)
# => ["this", "the", "string", "to's", "split", "real", "nice-like"]

When to use split, when to use scan

• When the delimiters are messy and making a regex match them is difficult, use scan.
• When the substrings to extract are messy and making a regex match them is difficult, use split.
• When you want to impose conditions on the form of the substrings to be extracted, you scan.
• When you want to impose conditions on the form of the delimiters, use split.

Answer 2

I'm not entirely clear on the problem domain, but if you just want to avoid the empty strings, why not split on one or more occurrences of your separators?

str.split /[\s\.,"]+/

Answer 3

I would think a simple way to do that is as follows:

str.split(/\s|\.|,|"/).select{|s| s.length >= MIN_LENGTH}