Format data in string to array? - ruby

Question

I need to convert data from a string to an array. The string looks like this:
{a,b,c{1,2,3},d,e,f{11,22,33},g}
The array that I want to receive should look like this:
[a, b, c1, c2, c3, d, e, f11, f22, f33, g]
I tried to use the split method but it works poorly.
arr = str.split(' ');
keys = arr[0][2..-2]
keys = keys.split(',')
Do you have any ideas how it could be implemented?

Answer 1

Here's what I'd use:
string = '{a,b,c{1,2,3},d,e,f{11,22,33},g}'
array = string.scan(/[a-z](?:{.+?})?/).flat_map{ |s|
if s['{']
prefix = s[0]
values = s.scan(/\d+/)
([prefix] * values.size).zip(values).map(&:join)
else
s
end
}
array # => ["a", "b", "c1", "c2", "c3", "d", "e", "f11", "f22", "f33", "g"]
Here's how it works:
string.scan(/[a-z](?:{.+?})?/) # => ["a", "b", "c{1,2,3}", "d", "e", "f{11,22,33}", "g"]
returns the string broken into chunks, looking for a single letter followed by an optional string of { with some text then }.
values = s.scan(/\d+/) # => ["1", "2", "3"], ["11", "22", "33"]
As it's running in flat_map, if { is found, the numbers are scanned out.
([prefix] * values.size).zip(values).map(&:join) # => ["c1", "c2", "c3"], ["f11", "f22", "f33"]
And then an array of the prefix, with the same number of elements as there are values is created and zipped together, resulting in:
[["c", "1"], ["c", "2"], ["c", "3"]], [["f", "11"], ["f", "22"], ["f", "33"]]
The join glues those sub-arrays together. And flat_map flattens any subarrays created so the resulting output is a single array.

Answer 2

You need to arr = str.split(',') in the first step, because there is no whitespace between the values.
Also keep in mind you have {} to handle too.

Answer 3

This worked for me with simple regex and gsubing (though Tin Man's solution is better ruby):
def my_string_to_array(input_string)
groups = input_string.scan(/\w+\{.*?\}/)
groups.each do |group|
modified = group.gsub(',', ",#{group.match(/\w+/)[0]}").delete("{}")
input_string.gsub!(group, modified)
end
created_array = input_string.delete("{}").split(',')
end
string = '{a,b,c{1,2,3},d,e,f{11,22,33},g}'
my_string_to_array(string)
=> ["a", "b", "c1", "c2", "c3", "d", "e", "f11", "f22", "f33", "g"]
The way it works is that it first finds the groups having alphabets followed by braces and digits (like c{1,2,3})
For each such group, it modifies it by gsubing ',' with ',<alphabet>' and removing the braces.
Next, it replaces these groups with the modified ones in the original string.
And finally it removes the starting and ending braces in the original string, and converts it into an array.