I need to reuse a textfile that is filled with one-liners such:
export NODE_CODE="mio12"
How can I do that in my Ruby program the var is created and assign as it is in the text file?
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Read the file and for each (matching) line create a variable and assign the value. (or maybe put them in a hash)Stefan– Stefan2022-07-09 21:03:36 +00:00Commented Jul 9, 2022 at 21:03
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Maybe the question then is how can I create that var name and assign it into that value in dynamically?Juanse Cora– Juanse Cora2022-07-09 21:32:42 +00:00Commented Jul 9, 2022 at 21:32
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1Possibly worth reading: stackoverflow.com/questions/16419767/ruby-dynamic-variable-name And the right answer is probably a hash.Chris– Chris2022-07-09 22:53:55 +00:00Commented Jul 9, 2022 at 22:53
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Is it bash executable script?mechnicov– mechnicov2022-07-09 23:18:20 +00:00Commented Jul 9, 2022 at 23:18
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2 Answers
If the file were a Ruby file, you could require it and be able to access the variables after that:
# variables.rb
VAR1 = "variable 1"
VAR2 = 2
# ruby.rb
require "variables"
puts VAR1
If you're not so lucky, you could read the file and then loop through the lines, looking for lines that match your criteria (Rubular is great here) and making use of Ruby's instance_variable_set method. The gsub is to deal with extra quotes when the matcher grabs a variable set as a string.
# variables.txt
export VAR1="variable 1"
export VAR2=2
# ruby.rb
variable_line = Regexp.new('export\s(\w*)=(.*)')
File.readlines("variables.txt").each do |line|
if match = variable_line.match(line)
instance_variable_set("@#{match[1].downcase}", match[2].gsub("\"", ""))
end
end
puts @var1
puts @var2
1 Comment
Juanse Cora
Thanks. That was the answer I was looking. Never heard about the method instance_variable_set
Creating a hash from this file can be a fairly simple thing.
For var.txt:
export BLAH=42
export WOOBLE=67
File.readlines("var.txt").each_with_object({}) { |line, h|
h[$1] = $2 if line =~ /^ export \s+ (.+?) \s* \= \s* (.+) $/x
}
# => {"BLAH"=>"42", "WOOBLE"=>"67"}
2 Comments
Juanse Cora
I don't see the line within the loop that simple.
Chris
The regular expression looks for an export line, with the name and the value matched as
$1 and $2. If the regex matches, and entry is put into the hash.