CODEWITHSUNDEEP
rubystringeval
Marisa
Marisa

Reputation: 25

How to convert a statement in a string into a format that can be evaluated (Ruby)

I am writing a quiz program where I need to store boolean statements as strings in an array and output them to the terminal as part of a question. I then want to evaluate the contents of these strings and return the value so that I can test whether I answered the question correctly. Here is what I'm trying to do:

questions = ["!true", "!false", "true || true", "true && false"...]
puts "Answer true or false"
puts questions[0]
answer = gets.chomp
# evaluate value of questions[0] and compare to answer
...

Storing just the statements doesn't work the way I need it to:

questions = [!true, !false, true || true, true && false...]
puts questions[3].to_s

It returns the evaluated statement, ie "false", not "true && false". Any ideas of how to approach this?

Upvotes: 0

Views: 215

Answers (1)

shivam
shivam

Reputation: 16506

You are looking for eval. Here:

a = "true && false"
eval a
# => false

a = "true && true"
eval a
# => true

eval will let you "convert a boolean statement stored in a string into a format that can be evaluated". You will need to change your logic accordingly to use it.

Upvotes: 2

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