Ruby – Checking for nil string before concatenating

code formattingruby

This question is similar to a LOT of questions, but in no such way is it anything of a duplicate. This question is about string concatenation and writing better code less than it is for checking nil/zero.

Currently I have:

file.puts "cn: " + (var1.nil? ? "UNKNOWN" : var1)

Which works fine, but doesn't look good. What is a better way to write this in ruby so that I am checking for nil and not concatenating it

Best Answer

You can do this:

file.puts "cn: " + (var1 || "UNKNOWN")

or, identically if you prefer:

file.puts "cn: " + (var1 or "UNKNOWN")

or my favourite, which I think is the most idiomatic ruby:

file.puts "cn: #{var1 or 'unknown'}"

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Ruby – How to generate a random string in Ruby

(0...8).map { (65 + rand(26)).chr }.join

I spend too much time golfing.

(0...50).map { ('a'..'z').to_a[rand(26)] }.join

And a last one that's even more confusing, but more flexible and wastes fewer cycles:

o = [('a'..'z'), ('A'..'Z')].map(&:to_a).flatten
string = (0...50).map { o[rand(o.length)] }.join

If you want to generate some random text then use the following:

50.times.map { (0...(rand(10))).map { ('a'..'z').to_a[rand(26)] }.join }.join(" ")

this code generates 50 random word string with words length less than 10 characters and then join with space

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

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

Best Answer

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