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I'm looking for a good way to avoid checking for nil at each level in deeply nested hashes. For example:
name = params[:company][:owner][:name] if params[:company] && params[:company][:owner] && params[:company][:owner][:name] This requires three checks, and makes for very ugly code. Any way to get around this?
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Nested hashes allow us to further group, or associate, the data we are working with. They help us to deal with situations in which a category or piece of data is associated not just to one discrete value, but to a collection of values.
Iterating over a HashYou can use the each method to iterate over all the elements in a Hash. However unlike Array#each , when you iterate over a Hash using each , it passes two values to the block: the key and the value of each element.
In Ruby you can create a Hash by assigning a key to a value with => , separate these key/value pairs with commas, and enclose the whole thing with curly braces.
Entries in a hash are often referred to as key-value pairs. This creates an associative representation of data. Most commonly, a hash is created using symbols as keys and any data types as values. All key-value pairs in a hash are surrounded by curly braces {} and comma separated.
Ruby 2.3.0 introduced a new method called dig on both Hash and Array that solves this problem entirely.
name = params.dig(:company, :owner, :name) It returns nil if the key is missing at any level.
If you are using a version of Ruby older than 2.3, you can use the ruby_dig gem or implement it yourself:
module RubyDig def dig(key, *rest) if value = (self[key] rescue nil) if rest.empty? value elsif value.respond_to?(:dig) value.dig(*rest) end end end end if RUBY_VERSION < '2.3' Array.send(:include, RubyDig) Hash.send(:include, RubyDig) end If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
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