Ruby get numerals from a string

Question

I have the following string from which I want to extract numerals into an array

b="yesterday: 136.00. current: *143.00*. change: *-7.00*. change_2: *5.15%*. high: 143.00. low: 143.00" 

So I first did,

c = b.split(". ")
d = c.map{ |x| x.scan(/[\d\.-]+/)[0] }.map(&:to_f)

However d returns:

[136.0, 143.0, -7.0, 2.0, 143.0, 143.0]

Instead of

[136.0, 143.0, -7.0, 5.15, 143.0, 143.0]

Answer 1

Try just:

b.scan(/(?<=[ *])-?\d[\d.]+/).map(&:to_f)
# => [136.0, 143.0, -7.0, 5.15, 143.0, 143.0]

Answer 2

b.scan(/-?\d+.\d{2}[%*.]?/).map(&:to_f)
#=> [136.0, 143.0, -7.0, 5.15, 143.0, 143.0]

Answer 3

For something this complex I think you should use a regex, so something like this

/^yesterday: ([0-9+]) .. / =~ b

you can use rubular to help figure out the regex

Since it appears like you are trying to parse a fairly complex string and get a specific set of numbers from the "fields" in that string, a good way to do this is with a regex.

One of the best tools to determine exactly what that regex needs to be is Rubular.

If you are unfamiliar with parsing a string using regex , please see the Regex class in the docs http://www.ruby-doc.org/core-2.1.1/Regexp.html

For example the following regex would get each of those numbers into a corresponding variable. The reqex method is a little more complex but also shows what you are intending to do.

^yesterday: (?<yesterday>[-]*\d+\.\d+)\. current: \*(?<current>[-]*\d+\.\d+)\*\. change: \*(?<change>[-]*\d+\.\d+)\*\. change_2: \*(?<change_2>[-]*\d+\.\d+)%\*\. high: (?<high>[-]*\d+\.\d+)\. low: (?<low>[-]*\d+\.\d+)$