Ruby Arrays

Question 1 of 10

1

Given the array definition below, which of the following statements does NOT return 'b':


arr = ['a', 'b', 'c', 'd', 'e']

Select one of the following:

```
arr[1]
```
```
arr.fetch('b')
```
```
arr.at(1)
```
```
arr.find{|i| i=='b'}
```

Explanation

Question 2 of 10

1

Given the array definition below, which of the following statements raises an exception:


arr = ['a', 'b', 'c', 'd', 'e']

Select one of the following:

arr.select{|i| i=='b' }.map(&:upcase)
arr.find{|i| i=='b' }.map(&:upcase)
arr.take(2).last(1).map(&:upcase)
arr.sample(3).map(&:upcase)

Explanation

Question 3 of 10

1

What is the output from the following:


arr = ['a', 'b', 'c', 'd', 'e']
arr.map(&:upcase).reject!{|i| i=='B' }
puts arr

Select one of the following:

```
[ A, C, D, E ]
```
```
[ B ]
```
```
[ a, b, c, d, e]
```
```
[ b ]
```

Explanation

Question 4 of 10

1

Which of the following techniques CANNOT be used to create an array composed of four "a" characters, i.e.


[ "a", "a", "a", "a"]

Select one of the following:

```
Array.new(4, "a")
```
```
["a"]*4
```
```
"aaaa".split
```
```
Array.new(4){|i| "a" }
```

Explanation

Question 5 of 10

1

Which of the following array comparisons (==) return a true value

Select one or more of the following:

```
["a", 5, "6"]==["a", 5.0, "6"]
```


["a", nil, 5, "6"].compact==["a", 5, "6", nil].compact


 ["a", 5, "6"].map(&:to_s)==["a", 5.0, 6].map(&:to_s)

```
["a", 5, "6"]==["a", 5.0, 6]
```
```
["a", 5, "6"]==["a", 5, "6", nil]
```

Explanation

Question 6 of 10

1

Which of the following will result in the string "12345"

Select one or more of the following:

```
(1...5).map(&:to_s).join('')
```
```
12345.to_s.split.sum('')
```
```
"54321".reverse
```
```
"54321".split.reverse.join
```

Explanation

Question 7 of 10

1

Given the array


nums = [8, 13, 27, 61, 50].shuffle

which of the following methods can we rely on to extract the even elements, 8 and 50?

Select one or more of the following:

```
nums.select{|n| n.even? }
```
```
nums.find{|n| n.even? }
```
```
nums.filter{|n| n.even? }
```
```
[nums[0], nums[-1]]
```

Explanation

Question 8 of 10

1

What is the expected output from the following code:


arr = ['a', 'b', 'c', 'd', 'e']
puts ['a', 'e', 'f'] | ['b'] & arr

Select one of the following:

```
['a', 'e', 'b']
```
```
['a', 'e', 'f', 'b']
```
```
['a', 'b', 'c', 'd', 'e', 'f']
```
```
['a', 'b', 'c', 'd', 'e']
```

Explanation

Question 9 of 10

1

What is the output after the following sequence of array operations:


foo  = ['a', 'b', 'c']
foo << "x"
foo.shift
foo.append(['d', 'e', 'f'])
foo.unshift("y")
foo.pop
puts foo

Select one of the following:

```
['y', 'b', 'c', 'x', 'd', 'e']
```
```
['y', 'b', 'c', 'x' ]
```
```
['a', 'b', 'c', 'd', 'e', 'f']
```
```
['a', 'b', 'c', ['d', 'e', 'f']]
```

Explanation

Question 10 of 10

1

What is the output from the following:


names = [ "Aodhan", "Domhnall", "Caoimhe", "Blaithin"]
scores = [ 68, 23, 88, 71 ]
puts names.zip(scores).sort_by{|el| el[1] }.last[0]

Select one of the following:

Aodhan
Domhnall
Caoimhe
Blaithin

	Created by Domhnall Murphy almost 2 years ago

A level VectorLogic Quiz on Ruby Arrays, created by Domhnall Murphy on 20/02/2023.

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Ruby Arrays

Ruby Arrays

Question 1 of 10

Given the array definition below, which of the following statements does NOT return 'b': arr = ['a', 'b', 'c', 'd', 'e']

Select one of the following:

Explanation

Question 2 of 10

Given the array definition below, which of the following statements raises an exception: arr = ['a', 'b', 'c', 'd', 'e']

Select one of the following:

Explanation

Question 3 of 10

What is the output from the following: arr = ['a', 'b', 'c', 'd', 'e'] arr.map(&:upcase).reject!{|i| i=='B' } puts arr

Select one of the following:

Explanation

Question 4 of 10

Which of the following techniques CANNOT be used to create an array composed of four "a" characters, i.e. [ "a", "a", "a", "a"]

Select one of the following:

Explanation

Question 5 of 10

Which of the following array comparisons (==) return a true value

Select one or more of the following:

Explanation

Question 6 of 10

Which of the following will result in the string "12345"

Select one or more of the following:

Explanation

Question 7 of 10

Given the array nums = [8, 13, 27, 61, 50].shuffle which of the following methods can we rely on to extract the even elements, 8 and 50?

Select one or more of the following:

Explanation

Question 8 of 10

What is the expected output from the following code: arr = ['a', 'b', 'c', 'd', 'e'] puts ['a', 'e', 'f'] | ['b'] & arr

Select one of the following:

Explanation

Question 9 of 10

What is the output after the following sequence of array operations: foo = ['a', 'b', 'c'] foo << "x" foo.shift foo.append(['d', 'e', 'f']) foo.unshift("y") foo.pop puts foo

Select one of the following:

Explanation

Question 10 of 10

What is the output from the following: names = [ "Aodhan", "Domhnall", "Caoimhe", "Blaithin"] scores = [ 68, 23, 88, 71 ] puts names.zip(scores).sort_by{|el| el[1] }.last[0]

Select one of the following:

Explanation

Given the array definition below, which of the following statements does NOT return 'b':

`arr = ['a', 'b', 'c', 'd', 'e']`

Given the array definition below, which of the following statements raises an exception:

`arr = ['a', 'b', 'c', 'd', 'e']`

What is the output from the following:
`arr = ['a', 'b', 'c', 'd', 'e'] arr.map(&:upcase).reject!{|i| i=='B' } puts arr`

Which of the following techniques CANNOT be used to create an array composed of four "a" characters, i.e.

`[ "a", "a", "a", "a"]`

Given the array
`nums = [8, 13, 27, 61, 50].shuffle`

which of the following methods can we rely on to extract the even elements, 8 and 50?

What is the expected output from the following code:
`arr = ['a', 'b', 'c', 'd', 'e'] puts ['a', 'e', 'f'] | ['b'] & arr`

What is the output after the following sequence of array operations:
`foo = ['a', 'b', 'c'] foo << "x" foo.shift foo.append(['d', 'e', 'f']) foo.unshift("y") foo.pop puts foo`

What is the output from the following:

`names = [ "Aodhan", "Domhnall", "Caoimhe", "Blaithin"] scores = [ 68, 23, 88, 71 ] puts names.zip(scores).sort_by{|el| el[1] }.last[0]`