I want to get delete_if to delete empty strings from an array. With the solution below, the array still contains many empty strings.
products = my_text.split(/\t+/)
products.delete_if {|element| element == " " || "" || element.nil?}
Is there anything missing?
The problem with your code is explained by Ed S.
Otherwise, you can do
products.reject! { |s| s.nil? || s.strip.empty? }
Why do you need to test nil? first? Let's check few lines.
nil.strip
# NoMethodError: undefined method `strip' for nil:NilClass
" ".strip
# => ""
Now, with a different order, what the code does if the object is a string, and then if it is nil.
" ".strip || " ".nil?
# => ""
nil.strip || nil.nil?
# NoMethodError: undefined method `strip' for nil:NilClass
# Oh you don't want that to happen, do you?
This means you don't want to call strip.empty? when your object is nil.
And as you know, when you have a || b, if a is truthy (i.e. not nil nor false), b will never be called.
You test first if the string is nil ; if it is, you don't need to check the right part (so you won't get a undefined method error) and the object will be removed from your products list.
nil: products.reject! { |s| s&.strip&.empty? }As per Rails 6.1, You can use compact_blank,
https://apidock.com/rails/v6.1.3.1/ActionController/Parameters/compact_blank
["a", "", " "].compact_blank
=> ["a"]
Well this is wrong:
element == " " || "" || element.nil?
Should be
products = products.delete_if {|element| element == " " || element == "" || element.nil?
Note that you had a || "" || in there. You weren't comparing element to "", you were testing the "truthiness" of "" (which evaluates to true btw, screwing up your empty string check).
This of course assumes your definition of an "empty string" is either nil, " ", or "". What about
" "
or even
" "
?
contains, it's a comparison against the value, no more. Use @oldergod's suggestion in the comments.I'm maybe a bit last here (where were you 6 years ago ?), but here is my suggestion,to handle nil , "" and " "
arr.compact.map(&:strip).reject(&:empty?)
For example:
["", nil, "toto", " "].compact.map(&:strip).reject(&:empty?)
# => ["toto"]
Happy Covid lock-down !
So if you have an array of strings could easily remove empty values using reject function:
Having an array of string like this one:
array = ["", "ABC", "DEF", ... , "", "ZXY"]
If you use reject:
array.reject(&:empty?)
Will output a clean array of string:
=> ["ABC", "DEF", "ZXY"]
String#strip each element then reject empty elements:
arr.map!(&:strip).reject!{|s| s.empty?}
products.reject! { |s| s.strip.empty? || s.nil? }products.reject! { |product| product.nil? || product.strip.empty? }otherwise you'll try tostripnilstriptosbefore evaluating whether or notswasnil. This should have raisedNoMethodError: undefined method 'strip' for nil:NilClass. By reversing the order, you can avoid that situation.