How to split string in ruby

Question

I have a string:

"1 chocolate bar at 25"

and I want to split this string into:

 [1, "chocolate bar", 25]

I don't know how to write a regex for this split. And I wanted to know whether there are any other functions to accomplish it.

Answer 1

You could use scan with a regex:

"1 chocolate bar at 25".scan(/^(\d+) ([\w ]+) at (\d+)$/).first

The above method doesn't work if item_name has special characters.

If you want a more robust solution, you can use split:

number1, *words, at, number2 = "1 chocolate bar at 25".split
p [number1, words.join(' '), number2]
# ["1", "chocolate bar", "25"]

number1 is the first part, number2 is the last one, at the second to last, and *words is an array with everything in-between. number2 is guaranteed to be the last word.

This method has the advantage of working even if there are numbers in the middle, " at " somewhere in the string or if prices are given as floats.

Answer 2

It is not necessary to use a regular expression.

str = "1 chocolate bar, 3 donuts and a 7up at 25"

i1 = str.index(' ')
  #=> 1
i2 = str.rindex(' at ')
  #=> 35
[str[0,i1].to_i, str[i1+1..i2-1], str[i2+3..-1].to_i]
  #=> [1, "chocolate bar, 3 donuts and a 7up", 25]

Answer 3

I would do:

> s="1 chocolate bar at 25"
> s.scan(/[\d ]+|[[:alpha:] ]+/)
=> ["1 ", "chocolate bar at ", "25"]

Then to get the integers and the stripped string:

> s.scan(/[\d ]+|[[:alpha:] ]+/).map {|s| Integer(s) rescue s.strip}
=> [1, "chocolate bar at", 25]

And to remove the " at":

> s.scan(/[\d ]+|[[:alpha:] ]+/).map {|s| Integer(s) rescue s[/.*(?=\s+at\s*)/]}
=> [1, "chocolate bar", 25]

Answer 4

You may try returning captures property of match method on regex (\d+) ([\w ]+) at (\d+):

string.match(/(\d+) +(\D+) +at +(\d+)/).captures

Live demo

Validating input string

If you didn't validate your input string to be within desired format already, then there may be a better approach in validating and capturing data. This solution also brings the idea of accepting any type of character in item_name field and decimal prices at the end:

string.match(/^(\d+) +(.*) +at +(\d+(?:\.\d+)?)$/).captures

Answer 5

You can also do something like this:

"1 chocolate bar at 25"
  .split()
  .reject {|string| string == "at" }
  .map {|string| string.scan(/^\D+$/).empty? ? string.to_i : string }

Code Example: http://ideone.com/s8OvlC

Answer 6

I live in the country where prices might be float, hence the more sophisticated matcher for the price.

"1 chocolate bar at 25".
  match(/\A(\d+)\s+(.*?)\s+at\s+(\d[.\d]*)\z/).
  captures
#⇒ ["1", "chocolate bar", "25"]