Is There a Better Way of Checking Nil or Length == 0 of a String in Ruby

Is There a Better Way of Checking Nil or Length == 0 of a String in Ruby?

When I'm not worried about performance, I'll often use this:

if my_string.to_s == ''
  # It's nil or empty
end

There are various variations, of course...

if my_string.to_s.strip.length == 0
  # It's nil, empty, or just whitespace
end

Testing for empty or nil-value string

The second clause does not need a !variable.nil? check—if evaluation reaches that point, variable.nil is guaranteed to be false (because of short-circuiting).

This should be sufficient:

variable = id if variable.nil? || variable.empty?

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If you're working with Ruby on Rails, Object.blank? solves this exact problem:

An object is blank if it’s false, empty, or a whitespace string. For example, "", " ", nil, [], and {} are all blank.

Best ruby idiom for nil or zero

Objects have a nil? method.

if val.nil? || val == 0
  [do something]
end

Or, for just one instruction:

[do something] if val.nil? || val == 0

Ruby way to check if a string is not blank?

string = ""

unless string.to_s.strip.empty?
  # ...
end

Checking if a variable is not nil and not zero in ruby

unless discount.nil? || discount == 0
  # ...
end

What is a better way to check for a nil object before calling a method on it?

Personally, I would use the or operator/keyword:

(financial_document.assets or []).length

Either way, .length is called on an array, giving you 0 if nil.

Rails Model method check if field nil, if so return empty string

You can, although this might not be what you wanted, simply remove any nil objects from the address Array using the #compact method, so that #empty? will work...:

def full_address
    [self.address1, self.address2, self.address3,
        self.city, self.state, self.zipcode].compact.reject!(&:empty?).join(', ')
end

You should be aware that this WILL return a partial address if SOME of the fields exist.

I would probably void any fault addresses (in this example I require just the first address line and the city fields):

def full_address
    return "" unless self.address1 && self.city && !self.address1.empty? && !self.city.empty? 
    [self.address1, self.address2, self.address3,
        self.city, self.state, self.zipcode].compact.reject!(&:empty?).join(', ')
end

Disregarding the few edits I made to the code, I would probably go with @Joseph's #present? together with the validation, since you're using Rails:

def full_address
    return "" unless self.address1 && self.city && self.address1.present? && self.city.present? 
    [self.address1, self.address2, self.address3,
        self.city, self.state, self.zipcode].reject!(&:present?).join(', ')
end

How to check if controller action variable is empty

I would just go with

if @post.url.nil? 

which returns true when @post.url is nil but false when @post.url is an empty string.

Alternatively, you can use

if @post.url.blank?

which returns true in both cases when @post.url is nil or an empty string.

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