CODEWITHSUNDEEP
rubystringintegertype-conversion
FOXintheBOX
FOXintheBOX

Reputation: 49

converting an array of strings to an array of integers in Ruby

Running the following:

print ['1','2','3'].each { |j| j.to_i }

generates the output:

["1", "2", "3"]

I'd like to understand why it doesn't generate:

[1,2,3]

Thanks!

Upvotes: 2

Views: 60

Answers (3)

owade
owade

Reputation: 306

Another way could be :

print ['1','2','3'].collect(&method(:Integer))

But note this can bring a downside to performance if you were to use in production..

Upvotes: 0

Zoran
Zoran

Reputation: 4226

Calling #each on an applicable object will return that object after the function has finished looping, which is why you're getting the original array.

If you're looking to modify the values in the array, according to some rule, and return the result as a new array, you can use #map:

arr = ['1', '2', '3']
arr.map {|j| j.to_i}
# => [1, 2, 3]

If you'd like to directly affect the original array, you can substitute the above with #map!, which would mutate the original array.

Hope this helps!

Upvotes: 1

Arsen
Arsen

Reputation: 10951

Because .each returns an original array. You have to use .map

['1','2','3'].map(&:to_i)
=> [1, 2, 3]

each definition:

rb_ary_each(VALUE array)
{
    long i;
    volatile VALUE ary = array;

    RETURN_SIZED_ENUMERATOR(ary, 0, 0, ary_enum_length);
    for (i=0; i<RARRAY_LEN(ary); i++) {
        rb_yield(RARRAY_AREF(ary, i));
    }
    return ary; # returns original array
}

Upvotes: 2

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