CODEWITHSUNDEEP
arraysruby
marcamillion
marcamillion

Reputation: 33755

How do I check to see if an array of arrays has a value within the inner arrays?

Say I have an array of arrays that looks like this:

[[1830, 1], [1859, 1]]

What I want to do is quickly scan the internal arrays to see if any of them contain the number 1830. If it does, I want it to return the entire array that includes the number 1830, aka [1830, 1] from the above example.

I know for a normal array of values, I would just do array.include? 1830, but that doesn't work here, as can be seen here:

@add_lines_num_start
#=> [[1830, 1], [1859, 1]]
@add_lines_num_start.include? 1830
#=> false
@add_lines_num_start.first.include? 1830
#=> true

How do I do that?

Upvotes: 0

Views: 47

Answers (1)

Andrey Deineko
Andrey Deineko

Reputation: 52357

a = [[1830, 1], [1859, 1]]
a.find { |ar| ar.grep(1830) }
#=> [1830, 1]

References:

edit 1

As @Ilya mentioned in comment, instead of traversing the whole array with grep you could use the method to return the boolean once element that matches the condition is found:

a.find { |ar| ar.include?(1830) }

References:

edit 2 (shamelessly stolen from @Cary's comment under OP)

In case you'll have more than one matching array in your array, you can use Enumerable#find_all:

a = [[1830, 1], [1859, 1], [1893, 1830]]
a.find_all { |ar| ar.include?(1830) }
#=> [[1830, 1], [1893, 1830]]

Upvotes: 6

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