How do I remove blank elements from an array?

Question

I have the following array

cities = [\"Kathmandu\", \"Pokhara\", \"\", \"Dharan\", \"Butwal\"]

I want to remove blank elements from the ar

Answer 1

Shortest way cities.select(&:present?)

Answer 2

compact_blank (Rails 6.1+)

If you are using Rails (or a standalone ActiveSupport), starting from version 6.1, there is a compact_blank method which removes blank values from arrays.

It uses Object#blank? under the hood for determining if an item is blank.

["Kathmandu", "Pokhara", "", "Dharan", nil, "Butwal"].compact_blank
# => ["Kathmandu", "Pokhara", "Dharan", "Butwal"]

[1, "", nil, 2, " ", [], {}, false, true].compact_blank
# => [1, 2, true]

Here is a link to the docs and a link to the relative PR.

A destructive variant is also available. See Array#compact_blank!.

---

If you need to remove only nil values,

please, consider using Ruby build-in Array#compact and Array#compact! methods.

["a", nil, "b", nil, "c", nil].compact
# => ["a", "b", "c"]

Answer 3

Try this:

puts ["Kathmandu", "Pokhara", "", "Dharan", "Butwal"] - [""]

Answer 4

Use reject:

>> cities = ["Kathmandu", "Pokhara", "", "Dharan", "Butwal"].reject{ |e| e.empty? }
=> ["Kathmandu", "Pokhara", "Dharan", "Butwal"]

Answer 5

Update with a strict with join & split

cities = ["Kathmandu", "Pokhara", "", "Dharan", "Butwal"]
cities.join(' ').split

Result will be:

["Kathmandu", "Pokhara", "Dharan", "Butwal"]

Note that: this doesn't work with a city with spaces

Answer 6

When I want to tidy up an array like this I use:

["Kathmandu", "Pokhara", "", "Dharan", "Butwal"] - ["", nil]

This will remove all blank or nil elements.