ruby 1.9 how to convert array to string without brackets

+8 votes
asked Oct 23, 2013 by chris

My question is about how to convert array elements to string in ruby 1.9 without getting the brackets and quotation marks. I've got an array (DB extract), from which I want to use to create a periodic report.

myArray = ["Apple", "Pear", "Banana", "2", "15", "12"]

In ruby 1.8 I had the following line

reportStr = "In the first quarter we sold " + myArray[3].to_s + " " + myArray[0].to_s + "(s)."
puts reportStr

Which produced the (wanted) output

In the first quarter we sold 2 Apple(s).

The same two lines in ruby 1.9 produce (not wanted)

In the first quarter we sold ["2"] ["Apple"] (s).

After reading in the documentation Ruby 1.9.3 doc#Array#slice I thought I could produce code like

reportStr = "In the first quarter we sold " + myArray[3] + " " + myArray[0] + "(s)."
puts reportStr

which returns a runtime error

/home/test/example.rb:450:in `+': can't convert Array into String (TypeError)

My current solution is to remove brackets and quotation marks with a temporary string, like

tempStr0 = myArray[0].to_s
myLength = tempStr0.length
tempStr0 = tempStr0[2..myLength-3]
tempStr3 = myArray[3].to_s
myLength = tempStr3.length
tempStr3 = tempStr3[2..myLength-3]
reportStr = "In the first quarter we sold " + tempStr3 + " " + tempStr0 + "(s)."
puts reportStr

which in general works.

However, what would be a more elegant "ruby" way how to do that?

4 Answers

+2 votes
answered Oct 23, 2013 by agis

Use interpolation instead of concatenation:

reportStr = "In the first quarter we sold #{myArray[3]} #{myArray[0]}(s)."

It's more idiomatic, more efficient, requires less typing and automatically calls to_s for you.

+1 vote
answered Oct 23, 2013 by hirolau

And if you need to do this for more than one fruit the best way is to transform the array and the use the each statement.

myArray = ["Apple", "Pear", "Banana", "2", "1", "12"]
num_of_products = 3

tranformed = myArray.each_slice(num_of_products).to_a.transpose
p tranformed #=> [["Apple", "2"], ["Pear", "1"], ["Banana", "12"]]

tranformed.each do |fruit, amount|
  puts "In the first quarter we sold #{amount} #{fruit}#{amount=='1' ? '':'s'}."
end 

#=>
#In the first quarter we sold 2 Apples.
#In the first quarter we sold 1 Pear.
#In the first quarter we sold 12 Bananas.
+17 votes
answered May 29, 2014 by santosh-sindham

You can use .join("") method For example the below array has three elements as

my_array = ["Apple", "Pear", "Banana"]

now

my_array.join(", ") #will return a string as below separating the elements with whatever is passed inside join

Apple, Pear, Banana

0 votes
answered Jun 6, 2017 by kayleefrye-ondeck

You can think of this as arrayToString()

array = array * " "

E.g.,

myArray = ["One.","_1_?! Really?!","Yes!"]

=> "One.","_1_?! Really?!","Yes!"

myArray = myArray * " "

=> "One. _1_?! Really?! Yes."

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