Include apostrophe with .split() - ruby-on-rails

Question

I'm trying to display an array of words from a user's post. However the method I'm using treats an apostrophe like whitespace.
<%= var = Post.pluck(:body) %>
<%= var.join.downcase.split(/\W+/) %>
So if the input text was: The baby's foot
it would output the baby s foot,
but it should be the baby's foot.
How do I accomplish that?

Answer 1

Accepted answer is too naïve:
▶ "It’s naïve approach".split(/[^'\w]+/)
#⇒ [
# [0] "It",
# [1] "s",
# [2] "nai",
# [3] "ve",
# [4] "approach"
# ]
this is because nowadays there is almost 2016 and many users might want to use their normal names, like, you know, José Østergaard. Punctuation is not only the apostroph, as you might notice.
▶ "It’s naïve approach".split(/[^'’\p{L}\p{M}]+/)
#⇒ [
# [0] "It’s",
# [1] "naïve",
# [2] "approach"
# ]
Further reading: Character Properties.

Answer 2

Along the lines of mudasobwa's answer, here's what \w and \W bring to the party:
chars = [*' ' .. "\x7e"].join
# => " !\"\#$%&'()*+,-./0123456789:;<=>?#ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~"
That's the usual visible lower-ASCII characters we'd see in code. See the Regexp documentation for more information.
Grabbing the characters that match \w returns:
chars.scan(/\w+/)
# => ["0123456789",
# "ABCDEFGHIJKLMNOPQRSTUVWXYZ",
# "_",
# "abcdefghijklmnopqrstuvwxyz"]
Conversely, grabbing the characters that don't match \w, or that match \W:
chars.scan(/\W+/)
# => [" !\"\#$%&'()*+,-./", ":;<=>?#", "[\\]^", "`", "{|}~"]
\w is defined as [a-zA-Z0-9_] which is not what you want to normally call "word" characters. Instead they're typically the characters we use to define variable names.
If you're dealing with only lower-ASCII characters, use the character-class
[a-zA-Z]
For instance:
chars = [*' ' .. "\x7e"].join
lower_ascii_chars = '[a-zA-Z]'
not_lower_ascii_chars = '[^a-zA-Z]'
chars.scan(/#{lower_ascii_chars}+/)
# => ["ABCDEFGHIJKLMNOPQRSTUVWXYZ", "abcdefghijklmnopqrstuvwxyz"]
chars.scan(/#{not_lower_ascii_chars}+/)
# => [" !\"\#$%&'()*+,-./0123456789:;<=>?#", "[\\]^_`", "{|}~"]
Instead of defining your own, you can take advantage of the POSIX definitions and character properties:
chars.scan(/[[:alpha:]]+/)
# => ["ABCDEFGHIJKLMNOPQRSTUVWXYZ", "abcdefghijklmnopqrstuvwxyz"]
chars.scan(/\p{Alpha}+/)
# => ["ABCDEFGHIJKLMNOPQRSTUVWXYZ", "abcdefghijklmnopqrstuvwxyz"]
Regular expressions always seem like a wonderful new wand to wave when extracting information from a string, but, like the Sorcerer's Apprentice found out, they can create havoc when misused or not understood.
Knowing this should help you write a bit more intelligent patterns. Apply that to what the documentation shows and you should be able to easily figure out a pattern that does what you want.

Answer 3

You can use below RegEx instead of /\W+/
var.join.downcase.split(/[^'\w]+/)
/\W/ refers to all non-word characters, apostrophe is one such non-word character.
To keep the code as close to original intent, we can use /[^'\w]/ - this means that all characters that are not apostrophe and word character.

Answer 4

Running that string through irb with the same split call that you wrote in your comment gets this:
irb(main):008:0> "The baby's foot".split(/\W+/)
=> ["The", "baby", "s", "foot"]
However, if you use split without an explicit delimiter, you get the split you're looking for:
irb(main):009:0> "The baby's foot".split
=> ["The", "baby's", "foot"]
Does that get you what you're looking for?