Compact for removing nil values in Ruby - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to remove nil values from the array.

Ruby

array = [1, nil, 2, nil, 3]
clean_array = array.[1]

Drag options to blanks, or click blank then click option'

Acompact

Bflatten

Cuniq

Dsort

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'flatten' which changes nested arrays instead of removing nils.

Using 'uniq' which removes duplicates but keeps nils.

Using 'sort' which orders elements but does not remove nils.

The compact method removes all nil values from an array.

2fill in blank

medium

Complete the code to remove nil values from the hash values.

Ruby

hash = {a: 1, b: nil, c: 3, d: nil}
clean_hash = hash.select { |_, v| v [1] }

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A>= 0

B== nil

C!= nil

D< 3

Attempts:

3 left

💡 Hint

Common Mistakes

Using '== nil' which keeps only nil values.

Using comparison operators that don't relate to nil.

The block keeps pairs where the value is not nil, effectively removing nil values.

3fill in blank

hard

Fix the error in the code to remove nil values from the array.

Ruby

numbers = [5, nil, 7, nil, 9]
numbers = numbers.[1]()

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Acompact!

Bcompact

Ccompacted

Dremove_nil

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'compact!' without parentheses which can cause syntax errors.

Using non-existent methods like 'compacted' or 'remove_nil'.

The method compact returns a new array without nils. compact! modifies in place but requires parentheses.

4fill in blank

hard

Complete the code to create a hash with word lengths, excluding nil words.

Ruby

words = ["apple", nil, "pear", nil, "plum"]
lengths = {word => 0: word.{BLANK_2}}

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A =>

B:

Clength

Dsize

Attempts:

3 left

💡 Hint

Common Mistakes

Using colon ':' instead of '=>', which is invalid in this context.

Using 'length' instead of 'size' (both work but only one is correct here).

The hash uses word => 0 syntax and size method to get word length.

5fill in blank

hard

Fill all three blanks to create a hash of uppercase words and their lengths, excluding nils.

Ruby

words = ["dog", nil, "cat", "bird"]
result = { [1]: [2] for word in words if word [3] nil }

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Aword.upcase()

Blen(word)

C!=

Dword.length

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'len(word)' which is Python syntax, not Ruby.

Using '==' instead of '!=' to exclude nil values.

The key is the uppercase word, the value is its length, and the condition excludes nils.